JP5254103B2 - Carbon-containing modified polystyrene resin foamed particles and method for producing the same, carbon-containing modified polystyrene resin foamed article and method for producing the same - Google Patents
Carbon-containing modified polystyrene resin foamed particles and method for producing the same, carbon-containing modified polystyrene resin foamed article and method for producing the same Download PDFInfo
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本発明は、カーボンを含有したポリプロピレン系樹脂を核にして、スチレンを重合させることで得られるカーボン含有改質ポリスチレン系樹脂粒子に発泡剤を含浸させ、さらに予備発泡させて得られたカーボン含有改質ポリスチレン系樹脂発泡粒子、該発泡粒子を型内発泡成形して得られたカーボン含有改質ポリスチレン系樹脂発泡成形体、およびこれらの製造方法に関する。 The present invention provides a carbon-containing modified polymer obtained by impregnating a carbon-containing modified polystyrene-based resin particle obtained by polymerizing styrene using a carbon-containing polypropylene-based resin as a core, and further pre-foaming. The present invention relates to expanded polystyrene-based resin expanded particles, carbon-containing modified polystyrene-based resin expanded molded products obtained by in-mold foam molding of the expanded particles, and methods for producing the same.
従来、ポリスチレン系樹脂予備発泡粒子を型内に充填して加熱、発泡させて得られるポリスチレン系樹脂発泡成形体は、剛性、断熱性、軽量性、耐水性および発泡成形性に優れていることが知られている。そのためこの発泡成形体は、緩衝材や建材用断熱材として広く用いられている。しかし、この発泡成形体は、耐薬品性および耐衝撃性に劣るといった問題点があった。
一方、ポリプロピレン系樹脂からなる発泡成形体は、耐薬品性および耐衝撃性に優れていることが知られている。そのためこの発泡成形体は、自動車関連部品に用いられている。しかし、ポリプロピレン系樹脂は発泡ガスの保持性に劣ることから、発泡成形条件を精密に制御する必要があるため、製造コストが高くつくという問題点がある。加えて、ポリスチレン系樹脂発泡成形体に比して剛性が劣る問題点もある。
前記ポリスチレン系樹脂とポリプロピレン系樹脂の問題点を解決するために、剛性および発泡成形性の良好なポリスチレン系樹脂と、耐薬品性および耐衝撃性の良好なポリプロピレン系樹脂とを複合化した発泡成形体が提案されている。
加えて、発泡成形体の用途によっては、黒色で着色されることが望まれる場合があり、黒色の着色剤としては、カーボンが知られている。
本発明に関係する従来技術としては、例えば、特許文献１〜５が挙げられる。
Conventionally, polystyrene resin foam moldings obtained by filling polystyrene resin pre-expanded particles in a mold and heating and foaming are excellent in rigidity, heat insulation, light weight, water resistance and foam moldability. Are known. Therefore, this foaming molding is widely used as a buffer material or a heat insulating material for building materials. However, this foam molded article has a problem that it is inferior in chemical resistance and impact resistance.
On the other hand, it is known that a foam molded article made of a polypropylene resin is excellent in chemical resistance and impact resistance. Therefore, this foaming molding is used for automobile-related parts. However, since the polypropylene-based resin is inferior in foaming gas retention, it is necessary to precisely control the foam molding conditions, and there is a problem that the manufacturing cost is high. In addition, there is a problem that the rigidity is inferior to that of the polystyrene-based resin foam molding.
In order to solve the problems of the polystyrene resin and the polypropylene resin, a foam molding in which a polystyrene resin having a good rigidity and foam moldability and a polypropylene resin having a good chemical resistance and impact resistance are combined. The body has been proposed.
In addition, depending on the use of the foamed molded product, it may be desired to be colored in black, and carbon is known as a black colorant.
Examples of conventional techniques related to the present invention include Patent Documents 1 to 5.
特許文献１には、ポリプロピレン系樹脂１００質量部に対して、１００〜４００質量部のポリスチレン系樹脂が含まれたポリスチレン改質ポリプロピレン系樹脂粒子であって、前記樹脂粒子にトリス（２，３−ジブロモプロピル）イソシアヌレートが主成分である難燃剤が前記樹脂粒子１００質量部に対して１．５〜８．０質量部含まれることを特徴とするスチレン改質ポリプロピレン系樹脂粒子が開示されている。
特許文献１の段落００７１には、水蒸気圧０．０５〜０．４０ＭＰａの雰囲気下、発泡性カーボン含有改質ポリスチレン系樹脂粒子を加熱することによってカーボン含有改質ポリスチレン系樹脂発泡粒子（以下、予備発泡粒子ともいう）を得ることが記載されている。しかし、実施例中には「嵩発泡倍数３０倍に予備発泡」との記載しかなく、予備発泡時の具体的な水蒸気圧及び温度等の予備発泡に関する記載はない。
また、得られる予備発泡粒子の最表層膜厚及び最表層に接する気泡の平均気泡径に関する記載もない。
Patent Document 1 discloses polystyrene-modified polypropylene resin particles containing 100 to 400 parts by mass of polystyrene resin with respect to 100 parts by mass of polypropylene resin, and tris (2,3- Disclosed is a styrene-modified polypropylene-based resin particle characterized in that a flame retardant containing dibromopropyl) isocyanurate as a main component is contained in an amount of 1.5 to 8.0 parts by mass with respect to 100 parts by mass of the resin particles. .
In Paragraph 0071 of Patent Document 1, carbon-containing modified polystyrene resin expanded particles (hereinafter referred to as “preliminary”) are prepared by heating the expandable carbon-containing modified polystyrene resin particles in an atmosphere having a water vapor pressure of 0.05 to 0.40 MPa. (Also referred to as expanded particles). However, in the examples, there is only a description of “pre-foaming at a bulk foaming ratio of 30 times”, and there is no description regarding pre-foaming such as specific water vapor pressure and temperature at the time of prefoaming.
Moreover, there is no description regarding the outermost layer thickness of the pre-expanded particles to be obtained and the average bubble diameter of the bubbles in contact with the outermost layer.
特許文献２には、カーボン含有ポリプロピレン系樹脂１００質量部に対して、ポリスチレン系樹脂を１００質量部以上４００質量部未満含有し、かつ、ＡＴＲ法赤外分光分析により測定された粒子中心部の赤外線吸収スペクトルから得られる６９８ｃｍ−１および１３７６ｃｍ−１における吸光度比（Ｄ６９８／Ｄ１３７６）より算出される粒子中心部のポリスチレン系樹脂比率が、粒子全体のポリスチレン系樹脂比率に対して１．２倍以上であるカーボン含有改質ポリスチレン系樹脂粒子１００質量部に対して、難燃剤を１．５質量部以上６質量部未満含有し、かつ、難燃助剤を０．１質量部以上３質量部未満含有することを特徴とする自己消火性カーボン含有改質ポリスチレン系樹脂粒子が開示されている。
この特許文献２についても、予備発泡時の具体的な水蒸気圧及び温度等の予備発泡に関する記載はない。
また、得られる予備発泡粒子の最表層膜厚及び最表層に接する気泡の平均気泡径に関する記載もない。
Patent Document 2 contains 100 parts by mass or more and less than 400 parts by mass of a polystyrene-based resin with respect to 100 parts by mass of a carbon-containing polypropylene-based resin, and infrared rays at the center of the particle measured by ATR infrared spectroscopy. absorption absorbance ratio at 698cm -1 and 1376cm -1 are obtained from the spectra (D698 / D1376) polystyrene type resin ratio of particles center is calculated from the 1.2 times or more relative to the polystyrene type resin ratio of total particles The flame retardant is contained in an amount of 1.5 parts by mass or more and less than 6 parts by mass and the flame retardant aid is contained in an amount of 0.1 part by mass or more and less than 3 parts by mass with respect to 100 parts by mass of the carbon-containing modified polystyrene resin particles. Self-extinguishing carbon-containing modified polystyrene resin particles are disclosed.
Also in this patent document 2, there is no description regarding pre-foaming such as specific water vapor pressure and temperature at the time of pre-foaming.
Moreover, there is no description regarding the outermost layer thickness of the pre-expanded particles to be obtained and the average bubble diameter of the bubbles in contact with the outermost layer.
特許文献３には、ポリプロピレン系樹脂１００質量部に対して、ポリスチレン系樹脂を１００質量部以上４００質量部未満含有し、かつ、ＡＴＲ法赤外分光分析により測定された粒子中心部の赤外線吸収スペクトルから得られる６９８ｃｍ−１および１３７６ｃｍ−１における吸光度比（Ｄ６９８／Ｄ１３７６）より算出される粒子中心部のポリスチレン系樹脂比率が、粒子全体のポリスチレン系樹脂比率に対して１．２倍以上であることを特徴とする改質ポリスチレン系樹脂粒子が開示されている。
この特許文献３についても、予備発泡時の具体的な水蒸気圧及び温度等の予備発泡に関する記載はない。
また、得られる予備発泡粒子の最表層膜厚及び最表層に接する気泡の平均気泡径に関する記載もない。
Patent Document 3 contains 100 parts by mass of polypropylene resin and 100 parts by mass or more and less than 400 parts by mass of a polystyrene resin, and the infrared absorption spectrum of the particle center measured by ATR infrared spectroscopy. polystyrene type resin ratio of particles center calculated from the absorbance ratio (D698 / D1376) in 698cm -1 and 1376cm -1 are obtained from and not less than 1.2 times the polystyrene-based resin ratio of total particles Modified polystyrene-based resin particles characterized by the above are disclosed.
Also in this patent document 3, there is no description regarding pre-foaming such as specific water vapor pressure and temperature at the time of pre-foaming.
Moreover, there is no description regarding the outermost layer thickness of the pre-expanded particles to be obtained and the average bubble diameter of the bubbles in contact with the outermost layer.
特許文献４には、カーボン含有ポリプロピレン系樹脂を含有し、前記カーボン含有ポリプロピレン系樹脂１００質量部に対して、ポリスチレン系樹脂を１００質量部以上４００質量部未満含有し、かつ、ＡＴＲ法赤外分光分析により測定された粒子中心部の赤外線吸収スペクトルから得られる６９８ｃｍ−１および１３７６ｃｍ−１における吸光度比（Ｄ６９８／Ｄ１３７６）より算出される粒子中心部のポリスチレン系樹脂比率が、粒子全体のポリスチレン系樹脂比率に対して１．２倍以上であるカーボン含有改質ポリスチレン系樹脂粒子が開示されている。
この特許文献４についても、予備発泡時の具体的な水蒸気圧及び温度等の予備発泡に関する記載はない。
また、得られる予備発泡粒子の最表層膜厚及び最表層に接する気泡の平均気泡径に関する記載もない。
また、特許文献４の実施例中には、カーボンの配合量１．８％未満でＬ値２０以下を満たすものは無く、Ｌ値２０以下の黒色度を達成するためにはカーボンの配合量を多くする必要がある。
Patent Document 4 contains a carbon-containing polypropylene resin, and contains 100 parts by mass or more and less than 400 parts by mass of a polystyrene resin with respect to 100 parts by mass of the carbon-containing polypropylene resin, and ATR infrared spectroscopy. polystyrene type resin ratio of particles center calculated from the absorbance ratio (D698 / D1376) in 698cm -1 and 1376cm -1 obtained from an infrared absorption spectrum of the measured particle center by analysis, the entire particle polystyrene resin Carbon-containing modified polystyrene resin particles that are 1.2 times or more of the ratio are disclosed.
Also in this patent document 4, there is no description regarding pre-foaming such as specific water vapor pressure and temperature at the time of pre-foaming.
Moreover, there is no description regarding the outermost layer thickness of the pre-expanded particles to be obtained and the average bubble diameter of the bubbles in contact with the outermost layer.
In addition, in the examples of Patent Document 4, there is no carbon content of less than 1.8% and satisfying an L value of 20 or less, and in order to achieve blackness with an L value of 20 or less, the amount of carbon is There is a need to do more.
特許文献５には、ポリエチレンを１〜１０質量％含有するポリプロピレンとポリエチレンとのランダム共重合体粒子２０〜７０質量％およびビニル芳香族モノマー３０〜８０質量％を水性媒体中に懸濁せしめ、これに重合触媒を加えて重合せしめて、グラフト重合した熱可塑性樹脂粒子を得、これを水性懸濁液中で発泡剤を圧入して発泡性熱可塑性樹脂粒子を得ることを特徴とする製造方法が開示されている。
この特許文献５には、予備発泡工程に「１１０℃ないし１５０℃の水蒸気又はオイルバスにて加熱」との記述があり、実施例の表中にも、発泡蒸気圧についての記述があるが、この特許文献５で製造される樹脂粒子は、前記の特許文献２及び４に開示されるような「カーボン含有ポリプロピレン系樹脂粒子の融点をＴ℃としたとき、（Ｔ−１０）℃〜（Ｔ＋２０）℃の温度で、前記スチレン系単量体の第１の重合を行う工程と、前記第１の重合工程に続いて、スチレン系単量体と、重合開始剤とを加え、かつ、（Ｔ−２５）℃〜（Ｔ＋１０）℃の温度とすることにより、前記カーボン含有ポリプロピレン系樹脂粒子への前記スチレン系単量体の含浸および第２の重合を行う工程とを有することを特徴とするカーボン含有改質ポリスチレン系樹脂粒子の製造方法。」とは異なり「押出機にて１ｍｍ〜３ｍｍの径を有するペレット化したポリエチレンを１％含有するポリプロピレンとポリエチレンとのランダム共重合体樹脂４０部を水１５０部、複分解法ピロリン酸マグネシウム０．２部、ドデシルベンゼンスルフォン酸ソーダ０．０２部の系に分散させ、系内を８５℃に維持しながら、スチレンモノマー６０部に過酸化ベンゾイル０．３部、ジクミルパーオキサイド及び架橋助剤を溶解した混合液を７時間を要して滴下せしめ、滴下終了後、更に１４０℃で４時間反応させた後、重合体粒子を得た」と記述されているため（つまり、製造方法が異なる）、本発明の樹脂粒子とはモルフォロジーで異なるものであるといえる。
また、特許文献２及び４に開示されるような「カーボン含有ポリプロピレン系樹脂１００質量部に対して、ポリスチレン系樹脂を１００質量部以上４００質量部未満含有し、かつ、ＡＴＲ法赤外分光分析により測定された粒子中心部の赤外線吸収スペクトルから得られる６９８ｃｍ−１および１３７６ｃｍ−１における吸光度比（Ｄ６９８／Ｄ１３７６）より算出される粒子中心部のポリスチレン系樹脂比率が、粒子全体のポリスチレン系樹脂比率に対して１．２倍以上であることを特徴とするカーボン含有改質ポリスチレン系樹脂粒子」との記載は無く、従って表層にポリプロピレン系樹脂が多く、中心にポリスチレン系樹脂が多い構造とはならない。
In Patent Document 5, 20 to 70% by mass of random copolymer particles of polypropylene and polyethylene containing 1 to 10% by mass of polyethylene and 30 to 80% by mass of vinyl aromatic monomer are suspended in an aqueous medium. And a polymerization catalyst is added to the polymer to obtain graft-polymerized thermoplastic resin particles, and a foaming thermoplastic resin particle is obtained by press-fitting a foaming agent in an aqueous suspension. It is disclosed.
In this Patent Document 5, there is a description of “heating in steam or oil bath at 110 ° C. to 150 ° C.” in the preliminary foaming step, and there is also a description of foaming vapor pressure in the table of Examples. The resin particles produced in Patent Document 5 are disclosed in the above-mentioned Patent Documents 2 and 4, “(T−10) ° C. to (T + 20, where T ° C. is the melting point of the carbon-containing polypropylene resin particles). ) At a temperature of ° C., the step of performing the first polymerization of the styrenic monomer, the styrenic monomer and the polymerization initiator are added following the first polymerization step, and (T And a step of impregnating the carbon-containing polypropylene resin particles with the styrenic monomer and performing a second polymerization by setting the temperature to −25) ° C. to (T + 10) ° C. Containing modified polystyrene tree Unlike the “particle manufacturing method.” 40 parts of a random copolymer resin of polypropylene and polyethylene containing 1% of pelletized polyethylene having a diameter of 1 mm to 3 mm in an extruder by 150 parts of water, metathesis pyrroline Disperse in a system of 0.2 parts of magnesium oxide and 0.02 parts of sodium dodecylbenzene sulfonate, and maintain the system at 85 ° C., while adding 60 parts of styrene monomer to 0.3 parts of benzoyl peroxide, dicumyl peroxide and The mixture solution in which the crosslinking aid was dissolved was dropped over 7 hours, and after completion of the dropwise addition, the mixture was further reacted at 140 ° C. for 4 hours to obtain polymer particles ”. It can be said that the resin particles of the present invention are different in morphology.
Further, as disclosed in Patent Documents 2 and 4, “100 parts by mass of the carbon-containing polypropylene resin is contained in a polystyrene resin of 100 parts by mass or more and less than 400 parts by mass, and by ATR infrared spectroscopy. absorbance ratio at 698cm -1 and 1376cm -1 obtained from an infrared absorption spectrum of the measured particle center (D698 / D1376) polystyrene type resin ratio of particles center calculated from the found the polystyrene-based resin ratio of total particles On the other hand, there is no description of “carbon-containing modified polystyrene resin particles characterized by being 1.2 times or more”, and therefore, a structure having a large amount of polypropylene resin in the surface layer and a large amount of polystyrene resin in the center is not obtained.
特許文献１〜４に開示された方法で得られたカーボン含有改質ポリスチレン系樹脂粒子は、表層にポリプロピレン系樹脂成分が多く、中心部にポリスチレン系樹脂成分が多い構造となる。この樹脂粒子に発泡剤を含浸させ、水蒸気圧０．０５〜０．４０ＭＰａの水蒸気を導入して加熱することによって予備発泡して得られる予備発泡粒子を型内発泡成形して得られた発泡成形体は、従来の自動車用内装材などの要求基準を十分に満たし得る黒色度及び耐熱性を有していた。 The carbon-containing modified polystyrene resin particles obtained by the methods disclosed in Patent Documents 1 to 4 have a structure in which the surface layer has a large amount of the polypropylene resin component and the center portion has a large amount of the polystyrene resin component. Foam molding obtained by in-mold foam molding of pre-foamed particles obtained by pre-foaming by impregnating the resin particles with a foaming agent, introducing steam with a steam pressure of 0.05 to 0.40 MPa, and heating. The body has blackness and heat resistance that can sufficiently satisfy the required standards such as conventional automotive interior materials.
しかしながら、自動車製造等の分野では、使用する内装材等の耐熱性や外観に関して、要求基準が益々厳しくなっており、前述した従来技術により製造されたカーボン含有改質ポリスチレン系樹脂発泡成形体では、今後の要求基準を十分に満足し得なくなることが予想される。 However, in the field of automobile production and the like, the required standards have become increasingly strict regarding the heat resistance and appearance of the interior materials used, etc. In the carbon-containing modified polystyrene resin foam molded article produced by the above-described conventional technology, It is expected that future requirements will not be fully satisfied.
本発明は、前記事情に鑑みてなされ、従来のカーボン含有改質ポリスチレン系樹脂発泡成形体よりも耐熱性及び黒色度をより改善させたカーボン含有改質ポリスチレン系樹脂発泡成形体の提供を目的とする。 The present invention was made in view of the above circumstances, and an object thereof is to provide a carbon-containing modified polystyrene resin foam molded article having improved heat resistance and blackness more than conventional carbon-containing modified polystyrene resin foam molded articles. To do.
前記目的を達成するため、本発明は、カーボン含有ポリプロピレン系樹脂１００質量部に対して、１００〜４００質量部のポリスチレン系樹脂を含むカーボン含有改質ポリスチレン系樹脂粒子に発泡剤を含浸させたカーボン含有発泡性改質ポリスチレン系樹脂粒子を嵩発泡倍数２０〜４５倍に予備発泡させて得られ、走査型電子顕微鏡を用いて観察された画像から算出した発泡粒子の最表層膜厚が５〜２５μｍであり、かつ走査型電子顕微鏡を用いて観察された画像から算出した発泡粒子の最表層に接している気泡の平均気泡径が１００〜６００μｍであることを特徴とするカーボン含有改質ポリスチレン系樹脂発泡粒子を提供する。 In order to achieve the above-mentioned object, the present invention provides carbon obtained by impregnating a foaming agent with carbon-containing modified polystyrene resin particles containing 100 to 400 parts by mass of polystyrene resin with respect to 100 parts by mass of carbon-containing polypropylene resin. The outermost layer film thickness of the expanded particles calculated from the images obtained by pre-expanding the expanded foam-modified polystyrene-based resin particles to a bulk expansion ratio of 20 to 45 times and observed using a scanning electron microscope is 5 to 25 μm. And an average cell diameter of bubbles in contact with the outermost layer of the expanded particles calculated from an image observed using a scanning electron microscope is 100 to 600 μm Provide expanded particles.
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子において、前記カーボン含有改質ポリスチレン系樹脂発泡粒子は、ＡＴＲ法赤外分光分析により測定された粒子表面の赤外線吸収スペクトルから得られる６９８ｃｍ−１および１３７６ｃｍ−１における吸光度比（Ｄ６９８／Ｄ１３７６）より算出される粒子表面のポリスチレン系樹脂比率が、粒子全体のポリスチレン系樹脂比率に対して０．５倍以下であることが好ましい。 In the carbon-containing modified polystyrene resin foamed particles of the present invention, the carbon-containing modified polystyrene resin foamed particles are 698 cm −1 and 1376 cm obtained from an infrared absorption spectrum of the particle surface measured by ATR infrared spectroscopy. The polystyrene resin ratio on the particle surface calculated from the absorbance ratio at -1 (D698 / D1376) is preferably 0.5 times or less with respect to the polystyrene resin ratio of the entire particle.
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子において、前記カーボン含有発泡性改質ポリスチレン系樹脂粒子をゲージ圧力０．００５〜０．０９ＭＰａの水蒸気を導入して加熱することによって予備発泡して得られたものであることが好ましい。 In the carbon-containing modified polystyrene resin foamed particles of the present invention, the carbon-containing foamed modified polystyrene resin particles are pre-foamed by introducing water vapor with a gauge pressure of 0.005 to 0.09 MPa and heating. It is preferable that
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子において、前記カーボン含有改質ポリスチレン系樹脂発泡粒子のカーボン含有量が１．０〜３．２％の範囲であることが好ましい。 In the carbon-containing modified polystyrene resin foamed particles of the present invention, the carbon content of the carbon-containing modified polystyrene resin foamed particles is preferably in the range of 1.0 to 3.2%.
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子において、前記カーボン含有改質ポリスチレン系樹脂１００質量部に対して、難燃剤を１．５質量部以上６質量部未満含有することが好ましい。
前記難燃剤としてはトリ（２，３−ジブロモプロピル）イソシアネートが好ましい。
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子において、前記カーボン含有改質ポリスチレン系樹脂１００質量部に対して、難燃助剤を０．１〜３質量部有することが好ましい。
前記難燃助剤としては２，３−ジメチル−２，３−ジフェニルブタンが好ましい。
In the carbon-containing modified polystyrene resin foamed particles of the present invention, it is preferable that the flame retardant is contained in an amount of 1.5 parts by mass or more and less than 6 parts by mass with respect to 100 parts by mass of the carbon-containing modified polystyrene resin.
The flame retardant is preferably tri (2,3-dibromopropyl) isocyanate.
In the carbon-containing modified polystyrene resin foamed particles of the present invention, it is preferable to have 0.1 to 3 parts by mass of a flame retardant aid with respect to 100 parts by mass of the carbon-containing modified polystyrene resin.
As the flame retardant aid, 2,3-dimethyl-2,3-diphenylbutane is preferable.
また本発明は、前記カーボン含有改質ポリスチレン系樹脂発泡粒子を型内に充填し発泡成形させてなるカーボン含有改質ポリスチレン系樹脂発泡成形体を提供する。 The present invention also provides a carbon-containing modified polystyrene resin foamed molded article obtained by filling the above-mentioned carbon-containing modified polystyrene resin foamed particles in a mold and foam-molding the mold.
また本発明は、分散剤を含む水性懸濁中に、カーボン含有ポリプロピレン系樹脂粒子１００質量部と、スチレン系単量体１００質量部以上４００質量部未満と、重合開始剤とを分散させる工程と、
得られた分散液を前記スチレン系単量体が実質的に重合しない温度に加熱して前記スチレン系単量体を前記カーボン含有ポリプロピレン系樹脂粒子に含浸させる工程と、
前記カーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点をＴ℃としたとき、（Ｔ−１０）℃〜（Ｔ＋２０）℃の温度で、前記スチレン系単量体の第１の重合を行う工程と、
前記第１の重合工程に続いて、スチレン系単量体と、重合開始剤とを加え、かつ、（Ｔ−２５）℃〜（Ｔ＋１０）℃の温度とすることにより、前記カーボン含有ポリプロピレン系樹脂粒子への前記スチレン系単量体の含浸および第２の重合を行ってカーボン含有改質ポリスチレン系樹脂粒子を得る工程と、
次いで、得られたカーボン含有改質ポリスチレン系樹脂粒子に発泡剤を含浸させて発泡性カーボン含有改質ポリスチレン系樹脂粒子を得る工程と、
次いで、得られた発泡性カーボン含有改質ポリスチレン系樹脂粒子を、ゲージ圧力０．００５〜０．０９ＭＰａの水蒸気を導入して加熱することによって予備発泡させて前述した本発明に係るカーボン含有改質ポリスチレン系樹脂発泡粒子を得ることを特徴とするカーボン含有改質ポリスチレン系樹脂発泡粒子の製造方法を提供する。
The present invention also includes a step of dispersing 100 parts by mass of carbon-containing polypropylene resin particles, 100 parts by mass or more and less than 400 parts by mass of a styrene monomer, and a polymerization initiator in an aqueous suspension containing a dispersant. ,
Heating the obtained dispersion to a temperature at which the styrenic monomer is not substantially polymerized to impregnate the carbon-containing polypropylene resin particles with the styrenic monomer;
The step of performing the first polymerization of the styrene monomer at a temperature of (T-10) ° C. to (T + 20) ° C., where T ° C. is the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles. When,
Subsequent to the first polymerization step, a styrene monomer and a polymerization initiator are added, and the temperature is set to (T-25) ° C. to (T + 10) ° C. Performing impregnation of the styrenic monomer into particles and second polymerization to obtain carbon-containing modified polystyrene resin particles;
Next, a step of impregnating the obtained carbon-containing modified polystyrene resin particles with a foaming agent to obtain expandable carbon-containing modified polystyrene resin particles;
Next, the obtained expandable carbon-containing modified polystyrene resin particles were pre-expanded by introducing water vapor with a gauge pressure of 0.005 to 0.09 MPa and heated, and the carbon-containing modified according to the present invention described above. Provided is a method for producing a carbon-containing modified polystyrene resin expanded particle, which is characterized by obtaining expanded polystyrene resin particles.
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子の製造方法において、前記第２の重合中の樹脂粒子、もしくは、前記第２の重合終了後の樹脂粒子に、難燃剤を含浸させる工程を有することが好ましい。 In the method for producing a carbon-containing modified polystyrene resin foamed particle of the present invention, the method includes a step of impregnating the resin particle during the second polymerization or the resin particle after the completion of the second polymerization with a flame retardant. Is preferred.
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子の製造方法において、前記カーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点が１２０℃〜１４５℃であることが好ましい。
また、前記カーボン含有ポリプロピレン系樹脂中のポリプロピレン系樹脂が、プロピレン−エチレン共重合体であることが好ましい。
In the method for producing carbon-containing modified polystyrene resin expanded particles of the present invention, the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles is preferably 120 ° C to 145 ° C.
Moreover, it is preferable that the polypropylene resin in the carbon-containing polypropylene resin is a propylene-ethylene copolymer.
また本発明は、前記製造方法により得られたカーボン含有改質ポリスチレン系樹脂発泡粒子を成形型のキャビティ内に充填し、次いで型内発泡成形し、次いで成形体を成形型から離型するカーボン含有改質ポリスチレン系樹脂発泡成形体の製造方法を提供する。 The present invention also includes a carbon-containing modified polystyrene-based resin expanded particle obtained by the above production method, filled in a cavity of a mold, then subjected to in-mold foam molding, and then released from the mold. A method for producing a modified polystyrene-based resin foam molding is provided.
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子は、カーボン含有ポリプロピレン系樹脂１００質量部に対して、１００〜４００質量部のポリスチレン系樹脂を含むカーボン含有改質ポリスチレン系樹脂粒子に発泡剤を含浸させたカーボン含有発泡性改質ポリスチレン系樹脂粒子を嵩発泡倍数２０〜４５倍に予備発泡させて得られ、走査型電子顕微鏡を用いて観察された画像から算出した発泡粒子の最表層膜厚が５〜２５μｍであり、かつ走査型電子顕微鏡を用いて観察された画像から算出した発泡粒子の最表層に接している気泡の平均気泡径が１００〜６００μｍである構成としたことにより、これを型内発泡成形して得られる発泡成形体は、従来品と比べて耐熱性及び黒色度を高めることができる。 The carbon-containing modified polystyrene resin foam particles of the present invention impregnate carbon-containing modified polystyrene resin particles containing 100 to 400 parts by mass of polystyrene resin with a foaming agent for 100 parts by mass of carbon-containing polypropylene resin. The outermost layer film thickness of the expanded particles calculated from the image obtained by pre-expanding the carbon-containing expandable modified polystyrene resin particles having a bulk expansion ratio of 20 to 45 times and observed using a scanning electron microscope By setting the average bubble diameter of the bubbles in contact with the outermost layer of the foamed particles calculated from an image observed using an electron microscope of 5 to 25 μm to 100 to 600 μm, this is the mold. The foamed molded product obtained by inner foam molding can improve heat resistance and blackness as compared with conventional products.
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子は、カーボン含有ポリプロピレン系樹脂１００質量部に対して、１００〜４００質量部のポリスチレン系樹脂を含むカーボン含有改質ポリスチレン系樹脂粒子に発泡剤を含浸させたカーボン含有発泡性改質ポリスチレン系樹脂粒子を嵩発泡倍数２０〜４５倍に予備発泡させて得られ、走査型電子顕微鏡を用いて観察された画像から算出した発泡粒子の最表層膜厚が５〜２５μｍであり、かつ走査型電子顕微鏡を用いて観察された画像から算出した発泡粒子の最表層に接している気泡の平均気泡径が１００〜６００μｍであることを特徴としている。 The carbon-containing modified polystyrene resin foam particles of the present invention impregnate carbon-containing modified polystyrene resin particles containing 100 to 400 parts by mass of polystyrene resin with a foaming agent for 100 parts by mass of carbon-containing polypropylene resin. The outermost layer film thickness of the expanded particles calculated from the image obtained by pre-expanding the carbon-containing expandable modified polystyrene resin particles having a bulk expansion ratio of 20 to 45 times and observed using a scanning electron microscope The average bubble diameter of the bubbles in contact with the outermost layer of the expanded particles, which is 5 to 25 μm and calculated from the image observed using a scanning electron microscope, is 100 to 600 μm.
本発明の改質ポリスチレン系樹脂発泡粒子の樹脂材料の一つである、ポリプロピレン系樹脂としては、特に限定されず、公知の重合方法で得られた樹脂を使用できるが、例えば、プロピレン−エチレン共重合体が用いられる。このプロピレン−エチレン共重合体は、エチレンとプロピレンの共重合体を主成分とするものであるが、エチレンまたはプロピレンと共重合し得る他の単量体を分子内に含有するものであってもよい。そのような単量体としては、α−オレフィン、環状オレフィン、ジエン系単量体から選択された一種または二種以上のものが挙げられる。 The polypropylene resin, which is one of the resin materials of the modified polystyrene resin foamed particles of the present invention, is not particularly limited, and a resin obtained by a known polymerization method can be used. A polymer is used. This propylene-ethylene copolymer is mainly composed of a copolymer of ethylene and propylene, but may contain ethylene or another monomer that can be copolymerized with propylene in the molecule. Good. Examples of such a monomer include one or more selected from α-olefins, cyclic olefins, and diene monomers.
本発明の好適な実施形態において、ポリプロピレン系樹脂として、１２０℃〜１４５℃の範囲の融点を有するものが用いられる。ポリプロピレン系樹脂の融点が、１２０℃より低いと耐熱性が乏しく、カーボン含有改質ポリスチレン系樹脂粒子を用いて製造されるカーボン含有改質ポリスチレン系樹脂発泡成形体の耐熱性が低くなってしまう。また、融点が１４５℃より高いと、重合温度が高くなり、良好な重合ができなくなる。 In a preferred embodiment of the present invention, a polypropylene resin having a melting point in the range of 120 ° C. to 145 ° C. is used. When the melting point of the polypropylene resin is lower than 120 ° C., the heat resistance is poor, and the heat resistance of the carbon-containing modified polystyrene resin foam molded article produced using the carbon-containing modified polystyrene resin particles is lowered. On the other hand, when the melting point is higher than 145 ° C., the polymerization temperature becomes high and good polymerization cannot be performed.
本発明の好適な実施形態において、カーボン含有ポリプロピレン系樹脂発泡粒子中のカーボンは、例えば、ファーネスブラック、ケッチェンブラック、チャンネルブラック、サーマルブラック、アセチレンブラック、黒鉛、炭素繊維などが挙げられる。
ポリプロピレン系樹脂に含有させる前において、カーボン（原料カーボン）は、粒子状であることが好ましく、原料カーボンの平均粒径は、通常、５ｎｍ〜１００ｎｍが好適であり、さらに好ましくは、１５ｎｍ〜３５ｎｍである。なお、原料カーボンの粒径は、平均粒子径を意味し、平均粒子径は、電子顕微鏡による算術平均である。本発明に用いられるカーボンブラックを特徴づける平均粒子径は、カーボンブラックの集合体を構成する小さな球状（微結晶による輪郭を有し、分離できない）成分を電子顕微鏡写真にて測定、算出した粒子の直径の平均のことである。
In a preferred embodiment of the present invention, examples of carbon in the carbon-containing polypropylene-based resin expanded particles include furnace black, ketjen black, channel black, thermal black, acetylene black, graphite, and carbon fiber.
Before being included in the polypropylene resin, the carbon (raw material carbon) is preferably in the form of particles, and the average particle size of the raw material carbon is usually preferably 5 nm to 100 nm, and more preferably 15 nm to 35 nm. is there. In addition, the particle diameter of raw material carbon means an average particle diameter, and an average particle diameter is an arithmetic average by an electron microscope. The average particle size that characterizes the carbon black used in the present invention is the particle size measured and calculated by electron micrographs of small spherical components (contained by microcrystals that cannot be separated) constituting the carbon black aggregate. It is the average diameter.
また、本発明においてカーボンは、カーボン含有改質ポリスチレン系樹脂発泡粒子中に１．２〜３．２質量％含まれていることが好ましい。
カーボン含有改質ポリスチレン系樹脂発泡粒子中のカーボンの配合量が１．２質量％未満であれば、得られる発泡成形体が十分な黒色を呈することができないため好ましくない。一方、カーボンの配合量が３．２質量％を超えると、カーボン含有改質ポリスチレン系樹脂発泡粒子から得られる発泡成形体の燃焼速度が大きくなるため好ましくない。
In the present invention, carbon is preferably contained in the carbon-containing modified polystyrene-based resin expanded particles in an amount of 1.2 to 3.2% by mass.
If the amount of carbon in the carbon-containing modified polystyrene resin expanded particles is less than 1.2% by mass, the resulting expanded molded article cannot exhibit a sufficient black color, which is not preferable. On the other hand, if the amount of carbon exceeds 3.2% by mass, it is not preferable because the burning rate of the foamed molded article obtained from the carbon-containing modified polystyrene resin expanded particles becomes large.
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子は、嵩密度０．０２２〜０．０５０ｇ／ｃｍ３を有する。嵩密度が０．０２２ｇ／ｃｍ３より小さいと、予備発泡粒子を発泡させて得られる発泡成形体の黒色度が低下するため好ましくない。一方、嵩密度が０．０５０ｇ／ｃｍ３より大きいと、予備発泡粒子を発泡させて得られる発泡成形体の質量が増加するので好ましくない。
また、この嵩密度を嵩発泡倍数で表すと、嵩発泡倍数（倍）＝１／嵩密度（ｇ／ｃｍ３）であることから、この予備発泡粒子は２０〜４５（倍）の嵩発泡倍数を有する。
The carbon-containing modified polystyrene resin foamed particles of the present invention have a bulk density of 0.022 to 0.050 g / cm 3 . When the bulk density is less than 0.022 g / cm 3, the blackness of the foamed molded product obtained by foaming the pre-foamed particles is unfavorable. On the other hand, if the bulk density is larger than 0.050 g / cm 3 , the mass of the foamed molded product obtained by foaming the pre-foamed particles is not preferable.
Moreover, when this bulk density is expressed by a bulk foaming factor, it is bulk foaming factor (times) = 1 / bulk density (g / cm 3 ), so this pre-expanded particle has a bulk foaming factor of 20 to 45 (times). Have
前記ポリプロピレン系樹脂には、必要に応じて、難燃剤、難燃助剤、酸化防止剤、紫外線吸収剤、顔料、着色剤などの添加物が含まれていてもよい。 The polypropylene-based resin may contain additives such as a flame retardant, a flame retardant aid, an antioxidant, an ultraviolet absorber, a pigment, and a colorant as necessary.
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子において、難燃剤としては、有機系難燃剤及び無機系難燃剤の中から適宜選択して使用でき、例えば、トリ（２，３−ジブロモプロピル）イソシアネートが挙げられる。この難燃剤は、カーボン含有ポリプロピレン系樹脂１００質量部に対して、難燃剤を１．５質量部以上６質量部未満含有することが好ましく、２．０質量部以上５質量部未満含有することが更に好ましい。カーボン含有ポリプロピレン系樹脂１００質量部に対して、難燃剤を１．５質量部以上６質量部未満含有させることで、本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子の効果、すなわち、ポリスチレン系樹脂発泡体とポリプロピレン系樹脂発泡成形体のそれぞれの長所が生かされ、剛性、発泡成形性、耐薬品性、耐熱性および黒色度に優れた発泡成形体を得ることができるという効果を損なうことなく、発泡成形体に難燃性を付与することができる。 In the carbon-containing modified polystyrene resin foamed particles of the present invention, the flame retardant can be appropriately selected from organic flame retardants and inorganic flame retardants. For example, tri (2,3-dibromopropyl) isocyanate Is mentioned. This flame retardant preferably contains 1.5 parts by mass or more and less than 6 parts by mass, preferably 2.0 parts by mass or more and less than 5 parts by mass with respect to 100 parts by mass of the carbon-containing polypropylene resin. Further preferred. The effect of the carbon-containing modified polystyrene-based resin expanded particles of the present invention, that is, the polystyrene-based resin, by containing a flame retardant of 1.5 to 6 parts by mass with respect to 100 parts by mass of the carbon-containing polypropylene-based resin. The advantages of each of the foam and the polypropylene resin foam molded article are utilized, without impairing the effect that a foam molded article excellent in rigidity, foam moldability, chemical resistance, heat resistance and blackness can be obtained. Flame retardancy can be imparted to the foamed molded product.
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子において、難燃助剤としては、２，３−ジメチル−２，３−ジフェニルブタン、３，４−ジメチル−３，４−ジフェニルヘキサン、ジクミルパーオキサイド、クメンヒドロパーオキサイドの有機過酸化物の群から選択された１種または２種以上が挙げられる。
難燃剤助は、カーボン含有改質ポリスチレン系樹脂粒子１００質量部に対して、０．１〜３質量部の範囲とされる。好ましい難燃助剤の配合量は、０．５〜２．５質量部であり、１〜２質量部がより好ましい。難燃助剤の配合量が０．１質量部より少ないと、予備発泡粒子を二次発泡させて得られる発泡成形体の自己消火性が低下するため好ましくない。一方、難燃助剤の配合量が３質量部より多いと、予備発泡粒子を二次発泡させて得られる発泡成形体の加熱寸法変化が大きくなるため好ましくない。
In the carbon-containing modified polystyrene resin foamed particles of the present invention, as the flame retardant aid, 2,3-dimethyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane, dicumylper One type or two or more types selected from the group of organic peroxides of oxide and cumene hydroperoxide are mentioned.
The flame retardant assistant is in the range of 0.1 to 3 parts by mass with respect to 100 parts by mass of the carbon-containing modified polystyrene resin particles. The compounding quantity of a preferable flame retardant adjuvant is 0.5-2.5 mass parts, and 1-2 mass parts is more preferable. When the blending amount of the flame retardant aid is less than 0.1 parts by mass, the self-extinguishing property of the foamed molded article obtained by secondary foaming of the pre-foamed particles is not preferable. On the other hand, when the blending amount of the flame retardant aid is more than 3 parts by mass, the change in the heating dimension of the foamed molded product obtained by secondary foaming of the pre-foamed particles is not preferable.
また、本発明のカーボン含有改質ポリスチレン系樹脂粒子において、難燃剤および難燃助剤を添加する場合は、粒子表面に多く存在していることが好ましいが、粒子中心部に偏在していてもよい。 In addition, in the carbon-containing modified polystyrene resin particles of the present invention, when a flame retardant and a flame retardant aid are added, it is preferable that the flame retardant and the flame retardant aid are present in a large amount on the particle surface. Good.
本発明のカーボン含有改質ポリスチレン系樹脂粒子において、カーボン以外にも着色剤を加えることができ、このような着色剤は、無機系の顔料であっても、有機系の顔料であってもよい。
無機系の顔料としては、例えば、黄鉛、亜鉛黄、バリウム黄などのクロム酸塩、紺青などのフェロシアン化物、カドミウムイエロー、カドミウムレッドなどの硫化物、鉄黒、紅殻などの酸化物、群青などのケイ酸塩、酸化チタンなどが挙げられる。
また、有機系の顔料としては、例えば、モノアゾ顔料、ジスアゾ顔料、アゾレーキ、縮合アゾ顔料、キレートアゾ顔料などのアゾ顔料、フタロシアニン系、アントラキノン系、ペリレン系、ペリノン系、チオインジゴ系、キナクリドン系、ジオキサジン系、イソインドリノン系、キノフタロン系などの多環式顔料などが挙げられる。
In the carbon-containing modified polystyrene resin particles of the present invention, a colorant can be added in addition to carbon, and such a colorant may be an inorganic pigment or an organic pigment. .
Examples of inorganic pigments include chromates such as chrome yellow, zinc yellow and barium yellow, ferrocyanides such as bitumen, sulfides such as cadmium yellow and cadmium red, oxides such as iron black and red husk, and ultramarine blue. And silicates such as titanium oxide.
Examples of organic pigments include azo pigments such as monoazo pigments, disazo pigments, azo lakes, condensed azo pigments, chelate azo pigments, phthalocyanine-based, anthraquinone-based, perylene-based, perinone-based, thioindigo-based, quinacridone-based, and dioxazine-based pigments. And polycyclic pigments such as isoindolinone and quinophthalone.
本発明のカーボン含有改質ポリスチレン系樹脂粒子のもう一つの樹脂材料である、ポリスチレン系樹脂としては、例えば、スチレン、α−メチルスチレン、ｐ−メチルスチレン、ｔ−ブチルスチレンなどのスチレン系単量体を重合させて得られる樹脂が挙げられる。さらに、ポリスチレン系樹脂は、スチレン系単量体と、該スチレン系単量体と共重合可能な他の単量体との共重合体であってもよい。他の単量体としては、ジビニルベンゼンのような多官能性単量体や、（メタ）アクリル酸ブチルのような構造中にベンゼン環を含まない（メタ）アクリル酸アルキルエステルなどが例示される。これら他の単量体は、実質的にポリスチレン系樹脂に対して５質量％を超えない範囲で使用してもよい。なお、本明細書では、スチレンおよびスチレンと共重合可能な単量体もスチレン系単量体と称している。 Examples of the polystyrene resin, which is another resin material of the carbon-containing modified polystyrene resin particles of the present invention, include a styrene-based monomer such as styrene, α-methylstyrene, p-methylstyrene, and t-butylstyrene. Examples thereof include resins obtained by polymerizing the body. Furthermore, the polystyrene resin may be a copolymer of a styrene monomer and another monomer copolymerizable with the styrene monomer. Examples of other monomers include polyfunctional monomers such as divinylbenzene, and (meth) acrylic acid alkyl esters that do not contain a benzene ring in the structure such as butyl (meth) acrylate. . You may use these other monomers in the range which does not exceed 5 mass% substantially with respect to a polystyrene-type resin. In the present specification, styrene and a monomer copolymerizable with styrene are also referred to as a styrene monomer.
ポリスチレン系樹脂は、カーボン含有ポリプロピレン系樹脂１００質量部に対して１００〜４００質量部の範囲の量とされる。好ましいポリスチレン系樹脂の配合量は、１２０〜３００質量部であり、１５０〜２５０質量部がより好ましい。
このポリスチレン系の樹脂の比率が４００質量部より多いと、予備発泡粒子を二次発泡させて得られる発泡成形体の耐薬品性および耐熱性が低下するため好ましくない。一方、配合量が１００質量部より少ないと、予備発泡粒子を二次発泡させて得られる発泡成形体の剛性が低下するため好ましくない。
The polystyrene resin is used in an amount in the range of 100 to 400 parts by mass with respect to 100 parts by mass of the carbon-containing polypropylene resin. The compounding quantity of a preferable polystyrene-type resin is 120-300 mass parts, and 150-250 mass parts is more preferable.
When the ratio of this polystyrene resin is more than 400 parts by mass, the chemical resistance and heat resistance of the foamed molded product obtained by secondary foaming of the pre-expanded particles are not preferable. On the other hand, when the blending amount is less than 100 parts by mass, the rigidity of the foamed molded product obtained by secondary foaming of the pre-foamed particles is unfavorable.
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子は、ＡＴＲ法赤外分光分析により測定された粒子表面の赤外線吸収スペクトルから得られる６９８ｃｍ−１および１３７６ｃｍ−１における吸光度比（Ｄ６９８／Ｄ１３７６）より算出される粒子表面のポリスチレン系樹脂比率が、粒子全体のポリスチレン系樹脂比率に対して０．５倍以下であることが好ましい。
なお、「粒子表面」とは、表面から深さ数μｍまでの領域を含む「表層」のことである。
Carbon-containing modified polystyrene resin foamed beads of the present invention, calculated from the absorbance ratio at 698cm -1 and 1376cm -1 obtained from an infrared absorption spectrum of the measured particle surface by ATR method infrared spectroscopy (D698 / D1376) It is preferable that the ratio of the polystyrene resin on the particle surface is 0.5 times or less with respect to the polystyrene resin ratio of the entire particle.
The “particle surface” is a “surface layer” including a region from the surface to a depth of several μm.
粒子表面のポリスチレン系樹脂比率が、粒子全体のポリスチレン系樹脂比率に対して０．５倍以下であれば、表層にポリプロピレン系樹脂が多くなっており、得られる発泡成形体の加熱寸法変化率、耐薬品性および黒色度がより向上する。 If the polystyrene resin ratio on the particle surface is 0.5 times or less of the polystyrene resin ratio of the entire particle, the surface layer has an increased amount of polypropylene resin, and the heating dimensional change rate of the resulting foam molded article, Improved chemical resistance and blackness.
さらに、本発明のカーボン含有改質ポリスチレン系樹脂粒子は、ＡＴＲ法赤外分光分析により測定された粒子表面の赤外線吸収スペクトルから得られる６９８ｃｍ−１および１３７６ｃｍ−１における吸光度比（Ｄ６９８／Ｄ１３７６）が０．１〜２．５の範囲であることが好ましく、より好ましくは０．８〜２．０の範囲であり、特に好ましくは１．０〜１．５の範囲である。
なお、粒子の表面とは、表面から深さ数μｍまでの領域を含む「表層」のことである。
Further, the carbon-containing modified polystyrene resin particles of the present invention, the absorbance ratio at 698cm -1 and 1376cm -1 obtained from an infrared absorption spectrum of the measured particle surface by ATR method infrared spectroscopy (D698 / D1376) is The range is preferably from 0.1 to 2.5, more preferably from 0.8 to 2.0, and particularly preferably from 1.0 to 1.5.
The surface of the particle is a “surface layer” including a region from the surface to a depth of several μm.
吸光度比が２．５より高いと、予備発泡粒子の表面におけるポリオレフィン系樹脂の比率が低下する。その結果、予備発泡粒子を発泡成形して得られる発泡成形体の耐薬品性および耐衝撃性が低下するので好ましくない。一方、吸光度比が０．１より低いと、予備発泡粒子表面からの発泡剤の散逸が顕著になることにより、型内での成形において粒子同士の融着が悪くなって耐衝撃性が逆に低下したり、収縮などによる発泡成形体の外観の仕上がり状態が悪くなったりする傾向があるので好ましくない。加えて、予備発泡粒子を製造する際に、スチレン系単量体のポリオレフィン系樹脂粒子への含浸、重合に要する時間が長くなって製造効率が低下するので好ましくない。 When the absorbance ratio is higher than 2.5, the ratio of the polyolefin resin on the surface of the pre-foamed particles is lowered. As a result, the chemical resistance and impact resistance of the foamed molded article obtained by foaming the pre-expanded particles are unfavorable. On the other hand, if the absorbance ratio is lower than 0.1, the dissipation of the foaming agent from the surface of the pre-foamed particles becomes significant, resulting in poor fusion between the particles during molding in the mold, and the impact resistance is reversed. This is not preferable because it tends to be lowered or the finished appearance of the foamed molded product is deteriorated due to shrinkage or the like. In addition, when pre-expanded particles are produced, the time required for the impregnation and polymerization of the styrene monomer into the polyolefin resin particles becomes longer, which is not preferable.
さらに、本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子は、発泡前の樹脂粒子の状態でＡＴＲ法赤外分光分析により測定された粒子中心部の赤外線吸収スペクトルから得られる６９８ｃｍ−１および１３７６ｃｍ−１における吸光度比（Ｄ６９８／Ｄ１３７６）より算出される粒子中心部のポリスチレン系樹脂比率が、粒子全体のポリスチレン系樹脂比率に対して１．２倍以上であり、好ましくは１．３５倍以上であり、特に好ましくは１．４倍以上である。
ここで「粒子中心部」とは、粒子の中心を通る断面において、粒子の中心から、その粒子の直径（粒径）の１／４までの範囲の部分のことであり、例えば、粒径が１ｍｍの球状の粒子における粒子中心部とは、この粒子の中心から、半径１２５μｍの範囲の部分のことである。
算出された粒子中心部のポリスチレン系樹脂比率が、粒子全体のポリスチレン系樹脂比率に対して１．２倍以下の場合、表層から内部にかけてポリスチレン系樹脂比率の傾斜の勾配が小さくなる。その結果、予備発泡粒子を発泡成形して得られる発泡成形体の発泡倍数および耐熱性が低下するので好ましくない。また、粒子中心部のポリスチレン系樹脂比率が、粒子全体のポリスチレン系樹脂比率に対して１．２倍以下の場合、粒子表面におけるポリスチレン系樹脂比率が高くなり、予備発泡粒子を発泡成形して得られる発泡成形体は十分な黒色度が得られなくなる。
Furthermore, the carbon-containing modified polystyrene resin foamed particles of the present invention are 698 cm −1 and 1376 cm − obtained from the infrared absorption spectrum of the particle center measured by ATR infrared spectroscopy in the state of the resin particles before foaming. The polystyrene resin ratio at the center of the particle calculated from the absorbance ratio at 1 (D698 / D1376) is 1.2 times or more, preferably 1.35 times or more with respect to the polystyrene resin ratio of the whole particle. Especially preferably, it is 1.4 times or more.
Here, the “particle central part” is a part in a cross section passing through the center of the particle, ranging from the center of the particle to ¼ of the diameter (particle diameter) of the particle. The particle central portion in a 1 mm spherical particle is a portion having a radius of 125 μm from the center of the particle.
When the calculated polystyrene resin ratio in the center of the particle is 1.2 times or less than the polystyrene resin ratio of the whole particle, the gradient of the gradient of the polystyrene resin ratio decreases from the surface layer to the inside. As a result, the expansion ratio and heat resistance of the foamed molded product obtained by foaming the pre-expanded particles are unfavorable. In addition, when the polystyrene resin ratio in the center of the particle is 1.2 times or less than the polystyrene resin ratio of the entire particle, the polystyrene resin ratio on the particle surface is increased, and the pre-expanded particles are obtained by foam molding. The resulting foamed molded article cannot obtain sufficient blackness.
ここで、本発明におけるＡＴＲ（Ａｔｔｅｎｕａｔｅｄ Ｔｏｔａｌ Ｒｅｆｌｅｃｔａｎｃｅ）法赤外分光分析とは、全反射吸収（Ａｔｔｅｎｕａｔｅｄ Ｔｏｔａｌ Ｒｅｆｌｅｃｔａｎｃｅ）を利用する一回反射型ＡＴＲ法により赤外吸収スペクトルを測定する分析方法である。この分析方法は、高い屈折率を持つＡＴＲプリズムを試料に密着させ、ＡＴＲプリズムを通して赤外線を試料に照射し、ＡＴＲプリズムからの反射光を分光分析する方法である。 Here, the ATR (Attenuated Total Reflectance) method infrared spectroscopic analysis in the present invention is an analysis method for measuring an infrared absorption spectrum by a single reflection type ATR method using total reflection absorption (Attenuated Total Reflectance). This analysis method is a method in which an ATR prism having a high refractive index is closely attached to a sample, infrared light is irradiated to the sample through the ATR prism, and the reflected light from the ATR prism is spectrally analyzed.
ＡＴＲ法赤外分光分析は、試料とＡＴＲプリズムとを密着させるだけでスペクトルを測定できるという簡便さ、深さ数μｍまでの表面分析が可能であるなどの理由で高分子材料などの有機物をはじめ、種々の物質の表面分析に広く利用されている。
なお、赤外吸収スペクトルから得られる６９８ｃｍ−１における吸光度Ｄ６９８は、ポリスチレン系樹脂に主に含まれるベンゼン環の面外変角振動に由来する６９８ｃｍ−１付近に現われるピークの高さをいう。
また、赤外吸収スペクトルから得られる１３７６ｃｍ−１における吸光度Ｄ１３７６は、ポリプロピレン系樹脂に含まれる−Ｃ−ＣＨ３炭化水素のＣＨ３の対称変角振動に由来する１３７６ｃｍ−１付近に現われるピークの高さをいう。
ATR infrared spectroscopic analysis is not limited to organic materials such as polymer materials because the spectrum can be measured simply by bringing the sample into close contact with the ATR prism and surface analysis up to a depth of several μm is possible. It is widely used for surface analysis of various substances.
In addition, the light absorbency D698 in 698cm < -1 > obtained from an infrared absorption spectrum says the height of the peak which appears in 698 cm < -1 > vicinity derived from the out-of-plane bending vibration of the benzene ring mainly contained in a polystyrene-type resin.
In addition, the absorbance D1376 at 1376 cm −1 obtained from the infrared absorption spectrum is a high peak appearing in the vicinity of 1376 cm −1 derived from the symmetrical bending vibration of CH 3 of —C—CH 3 hydrocarbon contained in the polypropylene resin. Say it.
吸光度比からポリスチレン系樹脂とポリプロピレン系樹脂の組成割合を求める方法としては、ポリスチレン系樹脂とポリプロピレン系樹脂とを所定の組成割合に均一に混合してなる複数種類の標準試料を後述の要領で作製し、各標準試料についてＡＴＲ法赤外分光分析により粒子表面分析を行なって赤外線吸収スペクトルを得る。得られた赤外吸収スペクトルのそれぞれから吸光度比を算出する。そして、縦軸に組成割合（標準試料中のポリスチレン系樹脂比率（質量％））を、横軸に吸光度比（Ｄ６９８／Ｄ１３７６）をとることで、検量線を描く。この検量線に基づいて、本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子の吸光度比から、本発明のカーボン含有改質ポリスチレン系樹脂粒子におけるポリスチレン系樹脂とポリプロピレン系樹脂の組成割合を求めることができる。
なお、前記検量線の作成に関しては、例えば、特許文献２〜４にも記載されている通り、従来周知である。
As a method for obtaining the composition ratio of polystyrene resin and polypropylene resin from the absorbance ratio, a plurality of types of standard samples prepared by uniformly mixing polystyrene resin and polypropylene resin at a predetermined composition ratio are prepared as described below. Then, each standard sample is subjected to particle surface analysis by ATR infrared spectroscopy to obtain an infrared absorption spectrum. The absorbance ratio is calculated from each of the obtained infrared absorption spectra. A calibration curve is drawn by taking the composition ratio (polystyrene resin ratio (% by mass) in the standard sample) on the vertical axis and the absorbance ratio (D698 / D1376) on the horizontal axis. Based on this calibration curve, the composition ratio of the polystyrene resin and the polypropylene resin in the carbon-containing modified polystyrene resin particles of the present invention can be obtained from the absorbance ratio of the carbon-containing modified polystyrene resin expanded particles of the present invention. it can.
The preparation of the calibration curve is conventionally known as described in, for example, Patent Documents 2 to 4.
本発明のカーボン含有改質ポリスチレン系樹脂発泡粒子は、カーボン含有ポリプロピレン系樹脂１００質量部に対して、１００〜４００質量部のポリスチレン系樹脂を含むカーボン含有改質ポリスチレン系樹脂粒子に発泡剤を含浸させたカーボン含有発泡性改質ポリスチレン系樹脂粒子を嵩発泡倍数２０〜４５倍に予備発泡させて得られ、走査型電子顕微鏡を用いて観察された画像から算出した発泡粒子の最表層膜厚が５〜２５μｍであり、かつ走査型電子顕微鏡を用いて観察された画像から算出した発泡粒子の最表層に接している気泡の平均気泡径が１００〜６００μｍである構成としたことにより、これを型内発泡成形して得られる発泡成形体は、従来品と比べて耐熱性及び黒色度を高めることができる。 The carbon-containing modified polystyrene resin foam particles of the present invention impregnate carbon-containing modified polystyrene resin particles containing 100 to 400 parts by mass of polystyrene resin with a foaming agent for 100 parts by mass of carbon-containing polypropylene resin. The outermost layer film thickness of the expanded particles calculated from the image obtained by pre-expanding the carbon-containing expandable modified polystyrene resin particles having a bulk expansion ratio of 20 to 45 times and observed using a scanning electron microscope By setting the average bubble diameter of the bubbles in contact with the outermost layer of the foamed particles calculated from an image observed using an electron microscope of 5 to 25 μm to 100 to 600 μm, this is the mold. The foamed molded product obtained by inner foam molding can improve heat resistance and blackness as compared with conventional products.
本発明に係るカーボン含有改質ポリスチレン系樹脂発泡粒子は、次の（Ａ）〜（Ｆ）の各工程を備えた、本発明に係るカーボン含有改質ポリスチレン系樹脂発泡粒子の製造方法により、効率よく、また歩留まりよく製造することができる。
（Ａ）分散剤を含む水性懸濁中に、カーボン含有ポリプロピレン系樹脂粒子１００質量部と、スチレン系単量体１００質量部以上４００質量部未満と、重合開始剤とを分散させる工程、
（Ｂ）得られた分散液を前記スチレン系単量体が実質的に重合しない温度に加熱して前記スチレン系単量体を前記カーボン含有ポリプロピレン系樹脂粒子に含浸させる工程、
（Ｃ）前記カーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点をＴ℃としたとき、（Ｔ−１０）℃〜（Ｔ＋２０）℃の温度で、前記スチレン系単量体の第１の重合を行う工程、
（Ｄ）前記第１の重合工程に続いて、スチレン系単量体と、重合開始剤とを加え、かつ、前記カーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点をＴ℃としたとき、（Ｔ−２５）℃〜（Ｔ＋１０）℃の温度とすることにより、前記カーボン含有ポリプロピレン系樹脂粒子への前記スチレン系単量体の含浸および第２の重合を行って、発泡性カーボン含有改質ポリスチレン系樹脂粒子を得る工程、
（Ｅ）次いで、得られたカーボン含有改質ポリスチレン系樹脂粒子に発泡剤を含浸させて発泡性カーボン含有改質ポリスチレン系樹脂粒子を得る工程、
（Ｆ）次いで、得られた発泡性カーボン含有改質ポリスチレン系樹脂粒子を、ゲージ圧０．００５ＭＰａ〜０．０９ＭＰａの範囲の圧力の水蒸気で加熱し予備発泡させて、前述した本発明に係るカーボン含有改質ポリスチレン系樹脂発泡粒子を得る工程。
なお、この（Ａ）〜（Ｄ）の各工程は、スチレン系単量体を原料としてビーズ状のポリスチレン系樹脂粒子を製造するポリスチレン系樹脂の懸濁重合法またはシード重合法などの周知の重合方法を実施する際に用いられるオートクレーブ重合装置などを用いて実施できるが、使用する製造装置はこれに限定されない。
The carbon-containing modified polystyrene resin foamed particles according to the present invention have the following steps (A) to (F), and the method for producing the carbon-containing modified polystyrene resin foamed particles according to the present invention is efficient. It can be manufactured with good and high yield.
(A) Dispersing 100 parts by mass of carbon-containing polypropylene resin particles, 100 parts by mass or more and less than 400 parts by mass of a styrene monomer, and a polymerization initiator in an aqueous suspension containing a dispersant;
(B) heating the obtained dispersion to a temperature at which the styrenic monomer is not substantially polymerized to impregnate the carbon-containing polypropylene resin particles with the styrenic monomer;
(C) When the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles is T ° C., the first polymerization of the styrene monomer at a temperature of (T−10) ° C. to (T + 20) ° C. The process of performing,
(D) When the styrene monomer and the polymerization initiator are added following the first polymerization step, and the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles is T ° C, By setting the temperature to (T-25) ° C. to (T + 10) ° C., the carbon-containing polypropylene resin particles are impregnated with the styrenic monomer and subjected to the second polymerization, and the expandable carbon-containing modification is performed. Obtaining polystyrene resin particles;
(E) Next, a step of impregnating the obtained carbon-containing modified polystyrene resin particles with a foaming agent to obtain expandable carbon-containing modified polystyrene resin particles,
(F) Next, the foamable carbon-containing modified polystyrene resin particles obtained are heated with water vapor having a gauge pressure in the range of 0.005 MPa to 0.09 MPa to be pre-foamed, and the carbon according to the present invention described above. A step of obtaining expanded polystyrene-based resin-containing particles.
In addition, each process of (A)-(D) is a well-known polymerization method such as a suspension polymerization method or a seed polymerization method of a polystyrene resin for producing beaded polystyrene resin particles using a styrene monomer as a raw material. Although it can implement using the autoclave polymerization apparatus etc. which are used when implementing a method, the manufacturing apparatus to be used is not limited to this.
前記（Ａ）工程において、カーボン含有ポリプロピレン系樹脂粒子は、例えば、前記のカーボン含有ポリプロピレン系樹脂を押出機で溶融し、ストランドカット、水中カット、ホットカットなどにより造粒ペレット化したり、また粉砕機にて直接樹脂粒子を粉砕しペレット化することにより得られる。また、その形状は、真球状、楕円球状（卵状）、円柱状、角柱状などが挙げられる。このカーボン含有ポリプロピレン系樹脂粒子の好ましい樹脂粒径は、０．５ｍｍ〜１．５ｍｍの範囲であり、より好ましくは、０．６ｍｍ〜１．０ｍｍの範囲がより好ましい。
また、前記（Ａ）工程において、カーボン含有ポリプロピレン系樹脂中のポリプロピレン系樹脂としては、融点が１２０℃〜１４５℃であるものが好適である。
In the step (A), for example, the carbon-containing polypropylene-based resin particles are obtained by melting the carbon-containing polypropylene-based resin with an extruder and granulating and pelletizing by strand cutting, underwater cutting, hot cutting, or the like. It can be obtained by directly pulverizing and pelletizing resin particles. In addition, examples of the shape include a true spherical shape, an elliptical spherical shape (egg shape), a cylindrical shape, and a prismatic shape. The preferred resin particle size of the carbon-containing polypropylene resin particles is in the range of 0.5 mm to 1.5 mm, more preferably in the range of 0.6 mm to 1.0 mm.
In the step (A), the polypropylene resin in the carbon-containing polypropylene resin preferably has a melting point of 120 ° C. to 145 ° C.
前記（Ａ）工程で用いられる分散剤としては、例えば、部分ケン化ポリビニルアルコール、ポリアクリル酸塩、ポリビニルピロリドン、カルボキシメチルセルロース、メチルセルロースなどの有機系分散剤、ピロリン酸マグネシウム、ピロリン酸カルシウム、リン酸カルシウム、炭酸カルシウム、リン酸マグネシウム、炭酸マグネシウム、酸化マグネシウムなどの無機系分散剤が挙げられる。この内、無機系分散剤が好ましい。無機系分散剤を用いる場合、界面活性剤を併用することが好ましい。このような界面活性剤としては、例えば、ドデシルベンゼンスルホン酸ソーダ、α−オレフィンスルホン酸ソーダなどが挙げられる。 Examples of the dispersant used in the step (A) include organic dispersants such as partially saponified polyvinyl alcohol, polyacrylate, polyvinyl pyrrolidone, carboxymethyl cellulose, and methyl cellulose, magnesium pyrophosphate, calcium pyrophosphate, calcium phosphate, and carbonic acid. Examples thereof include inorganic dispersants such as calcium, magnesium phosphate, magnesium carbonate, and magnesium oxide. Of these, inorganic dispersants are preferred. When using an inorganic dispersant, it is preferable to use a surfactant in combination. Examples of such a surfactant include sodium dodecylbenzene sulfonate and α-olefin sulfonic acid sodium.
また、重合開始剤としては、スチレン系単量体の重合に汎用されている従来周知の重合開始剤を使用できる。例えば、ベンゾイルパーオキサイド、ラウロイルパーオキサイド、ｔ−アミルパーオキシオクトエート、ｔ−ブチルパーオキシベンゾエート、ｔ−アミルパーオキシベンゾエート、ｔ−ブチルパーオキシビバレート、ｔ−ブチルパーオキシイソプロピルカーボネート、ｔ−ブチルパーオキシアセテート、ｔ−ブチルパーオキシ−３，３，５−トリメチルシクロヘキサノエート、ジ−ｔ−ブチルパーオキシヘキサハイドロテレフタレート、２，２−ジ−ｔ−ブチルパーオキシブタン、ジクミルパーオキサイドなどの有機過酸化物、アゾビスイソブチロニトリル、アゾビスジメチルバレロニトリルなどのアゾ化合物が挙げられる。なお、重合開始剤は、単独で用いられても併用されてもよい。 Moreover, as a polymerization initiator, the conventionally well-known polymerization initiator currently used widely for superposition | polymerization of a styrene-type monomer can be used. For example, benzoyl peroxide, lauroyl peroxide, t-amyl peroxy octoate, t-butyl peroxybenzoate, t-amyl peroxybenzoate, t-butyl peroxybivalate, t-butyl peroxyisopropyl carbonate, t- Butyl peroxyacetate, t-butylperoxy-3,3,5-trimethylcyclohexanoate, di-t-butylperoxyhexahydroterephthalate, 2,2-di-t-butylperoxybutane, dicumyl peroxide And azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile. In addition, a polymerization initiator may be used independently or may be used together.
また、架橋剤を添加する場合、その添加方法としては、例えば、架橋剤をカーボン含有ポリプロピレン系樹脂に直接添加する方法、溶剤、可塑剤またはスチレン系単量体に架橋剤を溶解させた上で添加する方法、架橋剤を水に分散させた上で添加する方法などが挙げられる。この内、スチレン系単量体に架橋剤を溶解させた上で添加する方法が好ましい。 In addition, when adding a crosslinking agent, for example, a method of directly adding the crosslinking agent to the carbon-containing polypropylene resin, or after dissolving the crosslinking agent in a solvent, a plasticizer or a styrene monomer. The method of adding, the method of adding after dispersing a crosslinking agent in water, etc. are mentioned. Among these, a method of adding a crosslinking agent after dissolving it in a styrene monomer is preferable.
スチレン系単量体は、カーボン含有ポリプロピレン系樹脂粒子に含浸させるために、水性媒体に、連続的にあるいは断続的に添加できる。スチレン系単量体は、水性媒体中に徐々に添加していくのが好ましい。水性媒体としては、水、水と水溶性媒体（例えば、アルコール）との混合媒体が挙げられる。 The styrenic monomer can be continuously or intermittently added to the aqueous medium in order to impregnate the carbon-containing polypropylene resin particles. The styrenic monomer is preferably added gradually to the aqueous medium. Examples of the aqueous medium include water and a mixed medium of water and a water-soluble medium (for example, alcohol).
前記（Ｂ）工程において、（Ａ）工程で得られた分散液を、スチレン系単量体が実質的に重合しない温度に加熱し、スチレン系単量体をカーボン含有ポリプロピレン系樹脂粒子に含浸させる際の温度は、４５℃〜７０℃の範囲、好ましくは５０℃〜６５℃の範囲とする。
この含浸温度が前記範囲未満であると、スチレン系単量体の含浸が不十分となってポリスチレンの重合粉末が生成されるので、好ましくない。一方、含浸温度が前記範囲を超えると、スチレン系単量体がカーボン含有ポリプロピレン系樹脂粒子に十分含浸される前に重合してしまうので、好ましくない。
In the step (B), the dispersion obtained in the step (A) is heated to a temperature at which the styrene monomer is not substantially polymerized, and the carbon-containing polypropylene resin particles are impregnated with the styrene monomer. The temperature at that time is in the range of 45 ° C to 70 ° C, preferably in the range of 50 ° C to 65 ° C.
When the impregnation temperature is less than the above range, the impregnation of the styrene monomer is insufficient and a polymerized polystyrene powder is generated, which is not preferable. On the other hand, when the impregnation temperature exceeds the above range, it is not preferable because the styrene monomer is polymerized before being sufficiently impregnated with the carbon-containing polypropylene resin particles.
前記（Ｃ）工程、および（Ｄ）工程において、重合温度は重要な要因であり、カーボン含有ポリプロピレン系樹脂中のポリプロピレン系樹脂の融点をＴ℃としたとき、（Ｃ）工程（第１の重合）では、（Ｔ−１０）℃〜（Ｔ＋２０）℃の温度範囲とし、（Ｄ）工程（第２の重合）では、（Ｔ−２５）℃〜（Ｔ＋１０）℃の温度範囲とする。
前記温度範囲で重合を行うことにより、樹脂粒子中心部は、ポリスチレン系樹脂の存在量が多く（つまり、表層にカーボン含有ポリプロピレン系樹脂の存在量が多い）、その結果として、ポリプロピレン系樹脂とポリスチレン系樹脂のそれぞれの長所が生かされ、剛性、発泡成形性、耐薬品性、耐熱性および黒色度に優れたカーボン含有改質ポリスチレン系樹脂粒子を提供することができる。
重合温度が前記温度範囲より低くなると、得られる樹脂粒子中心部にポリスチレン系樹脂の存在量が少なく、良好な物性を示す樹脂粒子や発泡成形体が得られない。また、重合温度が前記温度範囲より高くなると、スチレン系単量体がカーボン含有ポリプロピレン系樹脂粒子に十分含浸される前に重合が開始してしまうので、良好な物性を示す樹脂粒子や発泡成形体が得られない。また、耐熱性に優れた高価格の重合設備が必要になる。
In the steps (C) and (D), the polymerization temperature is an important factor. When the melting point of the polypropylene resin in the carbon-containing polypropylene resin is T ° C., the step (C) (first polymerization) ) In the temperature range of (T-10) ° C to (T + 20) ° C, and in the step (D) (second polymerization), the temperature range is in the range of (T-25) ° C to (T + 10) ° C.
By carrying out the polymerization in the temperature range, the resin particle center has a large amount of polystyrene resin (that is, a large amount of carbon-containing polypropylene resin in the surface layer), and as a result, the polypropylene resin and polystyrene. The advantages of each of the resin-based resins can be utilized to provide carbon-containing modified polystyrene-based resin particles having excellent rigidity, foam moldability, chemical resistance, heat resistance and blackness.
When the polymerization temperature is lower than the above temperature range, the abundance of the polystyrene-based resin is small at the center of the obtained resin particles, and resin particles and foamed molded articles exhibiting good physical properties cannot be obtained. In addition, when the polymerization temperature is higher than the above temperature range, the polymerization starts before the styrene monomer is sufficiently impregnated with the carbon-containing polypropylene resin particles. Cannot be obtained. In addition, an expensive polymerization facility with excellent heat resistance is required.
また、カーボン含有ポリプロピレン系樹脂粒子に含浸させたスチレン系単量体の重合する工程を、（Ｃ）工程（第１の重合）と、（Ｄ）工程（第２の重合）との二段階に分ける理由は、一度に多くのスチレン系単量体をカーボン含有ポリプロピレン系樹脂に含浸させようとすると、スチレン系単量体がカーボン含有ポリプロピレン系樹脂に十分に含浸されず、カーボン含有ポリプロピレン系樹脂の表面に残るからである。そこで、本発明に係る改質ポリスチレン系樹脂発泡粒子の製造方法のように、（Ｃ）工程と、（Ｄ）工程との二段階に分けることにより、（Ｃ）工程においてスチレン系単量体が確実にカーボン含有ポリプロピレン系樹脂の中心部に含浸され、（Ｄ）工程においてもスチレン系単量体がカーボン含有ポリプロピレン系樹脂の中心部に向かって含浸される。
また、前記（Ｄ）工程（第２の重合）において、前記第２の重合中の樹脂粒子、もしくは、前記第２の重合終了後の樹脂粒子に、難燃剤を含浸させることが好ましい。難燃剤を投入する際の投入温度は、３０℃〜９０℃の範囲が好ましく、５０℃〜７０℃の範囲がより好ましい。投入した後、難燃剤を含浸させる際の含浸温度は、難燃剤の融点をｔ℃としたとき、ｔ℃〜（ｔ＋３０）℃の範囲が好ましい。ｔ℃より低いと難燃剤がカーボン含有改質ポリスチレン系樹脂粒子に十分含浸されないおそれがあり、（ｔ＋３０）℃より高いと耐熱性に優れた高価格の重合設備が必要となる。
In addition, the step of polymerizing the styrene monomer impregnated in the carbon-containing polypropylene resin particles is divided into two steps, (C) step (first polymerization) and (D) step (second polymerization). The reason for the division is that if a carbon-containing polypropylene resin is impregnated with many styrene monomers at once, the styrene monomer is not sufficiently impregnated in the carbon-containing polypropylene resin, and the carbon-containing polypropylene resin This is because it remains on the surface. Then, like the manufacturing method of the modified polystyrene type resin expanded particles according to the present invention, the styrene monomer is separated in the (C) step by dividing into two steps of (C) step and (D) step. The carbon-containing polypropylene resin is surely impregnated in the center, and the styrene monomer is impregnated toward the center of the carbon-containing polypropylene resin also in the step (D).
In the step (D) (second polymerization), it is preferable to impregnate the resin particles during the second polymerization or the resin particles after the completion of the second polymerization with a flame retardant. The input temperature when adding the flame retardant is preferably in the range of 30 ° C to 90 ° C, more preferably in the range of 50 ° C to 70 ° C. After the addition, the impregnation temperature when impregnating the flame retardant is preferably in the range of t ° C. to (t + 30) ° C. when the melting point of the flame retardant is t ° C. If the temperature is lower than t ° C, the flame retardant may not be sufficiently impregnated into the carbon-containing modified polystyrene resin particles. If the temperature is higher than (t + 30) ° C, an expensive polymerization facility having excellent heat resistance is required.
前記（Ｄ）工程の重合を行った後、反応槽を冷却し、形成されたカーボン含有改質ポリスチレン系樹脂粒子を水性媒体と分離することで、カーボン含有ポリプロピレン系樹脂１００質量部に対して、ポリスチレン系樹脂を１００質量部以上４００質量部未満含有し、ＡＴＲ法赤外分光分析により測定された粒子表面の赤外線吸収スペクトルから得られる６９８ｃｍ−１および１３７６ｃｍ−１における吸光度比（Ｄ６９８／Ｄ１３７６）より算出される粒子表面のポリスチレン系樹脂比率が、粒子全体のポリスチレン系樹脂比率に対して０．５倍以下であるカーボン含有改質ポリスチレン系樹脂粒子が得られる。 After performing the polymerization in the step (D), the reaction vessel is cooled, and the formed carbon-containing modified polystyrene resin particles are separated from the aqueous medium, whereby 100 parts by mass of the carbon-containing polypropylene resin is obtained. the polystyrene resin contains less than 400 parts by mass or more to 100 parts by mass, from the absorbance ratio at 698cm -1 and 1376cm -1 obtained from an infrared absorption spectrum of the measured particle surface by ATR method infrared spectroscopy (D698 / D1376) Carbon-containing modified polystyrene resin particles in which the calculated polystyrene resin ratio on the particle surface is 0.5 times or less than the polystyrene resin ratio of the entire particles are obtained.
次に、（Ｅ）工程を行って発泡性カーボン含有改質ポリスチレン系樹脂粒子を得る。
前記（Ｅ）工程において、カーボン含有改質ポリスチレン系樹脂粒子に含浸させる発泡剤、好ましくは易揮発性発泡剤としては、沸点が重合体の軟化温度以下であり易揮発性を有するもの、例えば、プロパン、ｎ−ブタン、ｉ−ブタン、ｎ−ペンタン、ｉ−ペンタン、シクロペンタン、炭酸ガス、窒素が挙げられ、これらの発泡剤は、単独もしくは２種以上を併用して用いることができる。易揮発性発泡剤の使用量は、カーボン含有改質ポリスチレン系樹脂粒子１００質量部に対して５〜２５質量部の範囲とすることが好ましい。
Next, the step (E) is performed to obtain expandable carbon-containing modified polystyrene resin particles.
In the step (E), the foaming agent impregnated into the carbon-containing modified polystyrene resin particles, preferably a readily volatile foaming agent, has a boiling point that is lower than the softening temperature of the polymer and is easily volatile, for example, Examples include propane, n-butane, i-butane, n-pentane, i-pentane, cyclopentane, carbon dioxide gas, and nitrogen. These blowing agents can be used alone or in combination of two or more. The amount of the readily volatile foaming agent used is preferably in the range of 5 to 25 parts by mass with respect to 100 parts by mass of the carbon-containing modified polystyrene resin particles.
さらに、発泡助剤を発泡剤と共に用いてもよい。このような発泡助剤としては、例えば、トルエン、キシレン、エチルベンゼン、シクロヘキサン、Ｄ−リモネンなどの溶剤、ジイソブチルアジペート、ジアセチル化モノラウレート、やし油などの可塑剤（高沸点溶剤）が挙げられる。なお、発泡助剤の添加量としては、カーボン含有改質ポリスチレン系樹脂粒子１００質量部に対して０．１〜２．５質量部が好ましい。 Furthermore, you may use a foaming adjuvant with a foaming agent. Examples of such foaming aids include solvents such as toluene, xylene, ethylbenzene, cyclohexane, and D-limonene, and plasticizers (high-boiling solvents) such as diisobutyl adipate, diacetylated monolaurate, and palm oil. . In addition, as addition amount of a foaming adjuvant, 0.1-2.5 mass parts is preferable with respect to 100 mass parts of carbon containing modified polystyrene resin particles.
また、発泡性カーボン含有改質ポリスチレン系樹脂粒子には、結合防止剤、融着促進剤、帯電防止剤、展着剤などの表面処理剤を添加してもよい。 Further, a surface treatment agent such as a binding inhibitor, a fusion accelerator, an antistatic agent, or a spreading agent may be added to the expandable carbon-containing modified polystyrene resin particles.
結合防止剤は、発泡性カーボン含有改質ポリスチレン系樹脂粒子を予備発泡させる際の予備発泡粒子同士の合着を防止する役割を果たす。ここで、合着とは、予備発泡粒子の複数個が合一して一体化することをいう。具体例としては、タルク、炭酸カルシウム、ステアリン酸亜鉛、水酸化アルミニウム、エチレンビスステアリン酸アミド、第三リン酸カルシウム、ジメチルポリシロキサンなどが挙げられる。 The anti-bonding agent plays a role of preventing coalescence of the pre-expanded particles when pre-expanding the expandable carbon-containing modified polystyrene resin particles. Here, coalescence means that a plurality of pre-expanded particles are united and integrated. Specific examples include talc, calcium carbonate, zinc stearate, aluminum hydroxide, ethylene bis stearamide, tricalcium phosphate, dimethylpolysiloxane, and the like.
融着促進剤は、予備発泡粒子を二次発泡成形する際の予備発泡粒子同士の融着を促進させる役割を果たす。具体例としては、ステアリン酸、ステアリン酸トリグリセリド、ヒドロキシステアリン酸トリグリセリド、ステアリン酸ソルビタンエステルなどが挙げられる。
帯電防止剤としては、ポリオキシエチレンアルキルフェノールエーテル、ステアリン酸モノグリセリドなどが挙げられる。展着剤としては、ポリブテン、ポリエチレングリコール、シリコンオイルなどが挙げられる。なお、前記表面処理剤の総添加量は、改質ポリスチレン系樹脂粒子１００質量部に対して０．０１〜２．０質量部が好ましい。
The fusion accelerator plays a role of promoting fusion between the pre-foamed particles when the pre-foamed particles are subjected to secondary foam molding. Specific examples include stearic acid, stearic acid triglyceride, hydroxystearic acid triglyceride, sorbitan stearate, and the like.
Examples of the antistatic agent include polyoxyethylene alkylphenol ether and stearic acid monoglyceride. Examples of the spreading agent include polybutene, polyethylene glycol, and silicone oil. In addition, as for the total addition amount of the said surface treating agent, 0.01-2.0 mass parts is preferable with respect to 100 mass parts of modified polystyrene resin particles.
カーボン含有改質ポリスチレン系樹脂粒子中に発泡剤を含浸させる方法は、発泡剤の種類に応じて適宜変更可能である。例えば、カーボン含有改質ポリスチレン系樹脂粒子が分散している水性媒体中に発泡剤を圧入して、該樹脂中に発泡剤を含浸させる方法、カーボン含有改質ポリスチレン系樹脂粒子を回転混合機に供給し、この回転混合機内に発泡剤を圧入して該樹脂粒子に発泡剤を含浸させる方法などが挙げられる。なお、カーボン含有改質ポリスチレン系樹脂粒子に発泡剤を含浸させる温度は、通常、５０℃〜１４０℃とすることが好ましい。 The method of impregnating the carbon-containing modified polystyrene resin particles with the foaming agent can be appropriately changed according to the type of the foaming agent. For example, a method in which a foaming agent is pressed into an aqueous medium in which carbon-containing modified polystyrene resin particles are dispersed, and the foaming agent is impregnated in the resin, and the carbon-containing modified polystyrene resin particles are placed in a rotary mixer. Examples thereof include a method in which a foaming agent is pressed into the rotary mixer and the resin particles are impregnated with the foaming agent. The temperature at which the carbon-containing modified polystyrene resin particles are impregnated with the foaming agent is usually preferably 50 ° C to 140 ° C.
次に、（Ｆ）工程において、発泡性カーボン含有改質ポリスチレン系樹脂粒子を、予備発泡機缶内にゲージ圧０．００５ＭＰａ〜０．０９ＭＰａの範囲の水蒸気を導入して加熱することによって予備発泡させて、本発明に係るカーボン含有改質ポリスチレン系樹脂発泡粒子を得る。 Next, in the step (F), the expanded carbon-containing modified polystyrene resin particles are pre-expanded by introducing water vapor with a gauge pressure in the range of 0.005 MPa to 0.09 MPa into the preliminary foaming machine can and heating it. Thus, the carbon-containing modified polystyrene resin expanded particles according to the present invention are obtained.
本発明の製造方法では、この予備発泡において、ゲージ圧力０．００５〜０．０９ＭＰａの蒸気圧で加熱し、嵩発泡倍数２０〜４５倍に予備発泡させて前述した本発明に係る予備発泡粒子を得ることを特徴とする。
この予備発泡に用いる装置は、従来のポリスチレン系樹脂予備発泡粒子の製造の場合と異なり、高圧予備発泡機（例えば、笠原工業株式会社製、ＰＳＸ４０予備発泡機）などを用いる。
In the production method of the present invention, in this prefoaming, the prefoamed particles according to the present invention are heated by a vapor pressure of a gauge pressure of 0.005 to 0.09 MPa and prefoamed to a bulk foaming factor of 20 to 45 times. It is characterized by obtaining.
The apparatus used for this pre-foaming is different from the conventional production of polystyrene resin pre-foamed particles, and uses a high-pressure pre-foaming machine (for example, PSX40 pre-foaming machine manufactured by Kasahara Kogyo Co., Ltd.).
この予備発泡において、ゲージ圧力０．００５〜０．０９ＭＰａの蒸気圧で加熱し嵩発泡倍数２０〜４５倍に予備発泡させることで、前述したように、走査型電子顕微鏡を用いて観察された画像から算出した発泡粒子の最表層膜厚が５〜２５μｍであり、かつ走査型電子顕微鏡を用いて観察された画像から算出した発泡粒子の最表層に接している気泡の平均気泡径が１００〜６００μｍである構造の予備発泡粒子が得られる。加熱時間は一般に２０〜１２０秒程度である。 In this preliminary foaming, an image observed using a scanning electron microscope as described above by heating with a vapor pressure of a gauge pressure of 0.005 to 0.09 MPa and prefoaming to a bulk foaming factor of 20 to 45 times. The thickness of the outermost layer of the foamed particles calculated from the above is 5 to 25 μm, and the average bubble diameter of the bubbles in contact with the outermost layer of the foamed particles calculated from the image observed using a scanning electron microscope is 100 to 600 μm. Thus, pre-expanded particles having the following structure are obtained. The heating time is generally about 20 to 120 seconds.
この予備発泡粒子は、嵩密度０．０２２〜０．０５０ｇ／ｃｍ３（嵩発泡倍数で２０倍〜４５倍）を有する。嵩密度が０．０２２ｇ／ｃｍ３より小さいと、予備発泡粒子を発泡させて得られる発泡成形体の黒色度が低下するため好ましくない。一方、嵩密度が０．０５０ｇ／ｃｍ３より大きいと、予備発泡粒子を発泡させて得られる発泡成形体の質量が増加するので好ましくない。
予備発泡粒子の形態は、その後の型内発泡成形に影響を与えないものであれば、特に限定されない。例えば、真球状、楕円球状（卵状）、円柱状、角柱状などが挙げられる。この内、成形型のキャビティ内への充填が容易である真球状、楕円球状が好ましい。
The pre-expanded particles have a bulk density of 0.022 to 0.050 g / cm 3 (20 to 45 times as a bulk expansion factor). When the bulk density is less than 0.022 g / cm 3, the blackness of the foamed molded product obtained by foaming the pre-foamed particles is unfavorable. On the other hand, if the bulk density is larger than 0.050 g / cm 3 , the mass of the foamed molded product obtained by foaming the pre-foamed particles is not preferable.
The form of the pre-expanded particles is not particularly limited as long as it does not affect the subsequent in-mold foam molding. For example, a true spherical shape, an elliptical spherical shape (egg shape), a cylindrical shape, a prismatic shape, and the like can be given. Of these, a true spherical shape and an elliptical spherical shape, which can be easily filled into the cavity of the mold, are preferable.
本発明は、前述した予備発泡粒子を型内発泡成形して得られたカーボン含有改質ポリスチレン系樹脂発泡成形体（以下、発泡成形体ともいう。）とその製造方法を提供する。
前述した予備発泡粒子を発泡成形体とするには、前述した予備発泡粒子を通常２４時間程度保持して熟成させ、その後、予備発泡粒子を成形型のキャビティ内に充填し、加熱して型内発泡成形させ、該発泡粒子同士を融着一体化させることによって所望形状を有する発泡成形体を得ることができる。この型内発泡成形は、例えば、蒸気圧０．５〜４．５ｋｇ／ｃｍ２Ｇ程度（約０．０５〜０．４５ＭＰａ）の水蒸気を成形型内に導入することによって行うことができる。
The present invention provides a carbon-containing modified polystyrene resin foam molded article (hereinafter also referred to as a foam molded article) obtained by in-mold foam molding of the above pre-expanded particles and a method for producing the same.
In order to make the above-mentioned pre-expanded particles into a foam-molded product, the above-mentioned pre-expanded particles are usually held for about 24 hours and aged, and then the pre-expanded particles are filled into the mold cavity and heated to be heated in the mold. A foam-molded article having a desired shape can be obtained by foam-molding and fusing and integrating the foamed particles. This in-mold foam molding can be performed, for example, by introducing water vapor having a vapor pressure of about 0.5 to 4.5 kg / cm 2 G (about 0.05 to 0.45 MPa) into the mold.
本発明の発泡成形体は、密度が０．０２２〜０．０５ｇ／ｃｍ３の範囲である。
該発泡成形体の密度が０．０２２ｇ／ｃｍ３より小さいと、予備発泡粒子を発泡させて得られる発泡成形体の黒色度が低下するため好ましくない。一方、発泡成形体の密度が０．０５ｇ／ｃｍ３より大きいと、予備発泡粒子を発泡させて得られる発泡成形体の質量が増加するので好ましくない。また、この密度を発泡倍数で示すと、発泡倍数（倍）＝１／密度（ｇ／ｃｍ３）であることから、この発泡成形体は２０〜４５（倍）の発泡倍数を有する。
The foamed molded product of the present invention has a density in the range of 0.022 to 0.05 g / cm 3 .
When the density of the foamed molded product is smaller than 0.022 g / cm 3, the blackness of the foamed molded product obtained by foaming the pre-foamed particles is not preferable. On the other hand, if the density of the foamed molded product is larger than 0.05 g / cm 3 , the mass of the foamed molded product obtained by foaming the pre-expanded particles is not preferable. Moreover, when this density is expressed by a foaming multiple, since the foaming multiple (times) = 1 / density (g / cm 3 ), this foamed molded product has a foaming multiple of 20 to 45 (times).
また、本発明の発泡成形体は、ＪＩＳ Ｋ ６７６７に準拠した８５℃の条件下にて寸法変化測定における発泡成形体の加熱寸法変化率が絶対値で（以下、単に加熱寸法変化率と記す。）１．０％以下であることが望ましい。この加熱寸法変化率が１．０％を超えると、寸法の安定性に欠け好ましくない。
なお、加熱寸法変化率は小さい程望ましいので、その下限値を特に設ける必要はない。例えば、加熱寸法変化率の下限値は０であることが望ましい。
In the foamed molded product of the present invention, the heating dimensional change rate of the foamed molded product in a dimensional change measurement under the condition of 85 ° C. based on JIS K 6767 is an absolute value (hereinafter, simply referred to as a heated dimensional change rate). ) 1.0% or less is desirable. When the heating dimensional change rate exceeds 1.0%, the dimensional stability is not preferable.
In addition, since a heating dimensional change rate is so preferable that it is small, it is not necessary to provide the minimum in particular. For example, the lower limit value of the heating dimensional change rate is desirably 0.
本発明の発泡成形体は、前述した予備発泡粒子を型内発泡成形したものなので、剛性、発泡成形性、耐薬品性に優れ、特に耐熱性および黒色度に優れた発泡成形体を提供することができる。 Since the foamed molded article of the present invention is obtained by in-mold foam-molding the above-mentioned pre-expanded particles, the foamed molded article is excellent in rigidity, foam moldability, chemical resistance, and particularly excellent in heat resistance and blackness. Can do.
前述のように得られた発泡成形体は、自動車内装材（ツールボックス）、車輛用バンパーの芯材、ドア内装緩衝材などの車輛用緩衝材、電子部品、各種工業資材、食品などの搬送容器などの各種用途に用いることができる。 The foamed molded body obtained as described above is used for transporting automobile interior materials (tool boxes), vehicle bumper core materials, vehicle interior cushioning materials such as door interior cushioning materials, electronic parts, various industrial materials, foods, etc. It can be used for various applications such as.
以下、実施例により本発明を具体的に説明するが、本発明はこれに限定されるものではない。なお、以下の実施例における融点、嵩密度、密度、加熱寸法変化率、耐薬品性、黒色度、吸光度比、燃焼速度、予備発泡粒子の発泡性評価、予備発泡粒子の最表層膜厚の測定、予備発泡粒子最表層の気泡径の測定及びカーボンの配合量の測定法を下記する。 EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the following examples, melting point, bulk density, density, heating dimensional change rate, chemical resistance, blackness, absorbance ratio, burning rate, foamability evaluation of pre-foamed particles, measurement of outermost layer thickness of pre-foamed particles The method for measuring the bubble diameter of the outermost layer of the pre-expanded particles and the method for measuring the blending amount of carbon are described below.
＜融点＞
ＪＩＳ Ｋ７１２２：１９８７「プラスチックの転移熱測定方法」記載の方法により測定した。すなわち、示差走査熱量計装置ＤＳＣ２２０型（セイコー電子工業社製）を用い、測定容器に試料を７ｍｇ充填して、窒素ガス流量３０ｍｌ／ｍｉｎのもと、室温から２２０℃の間で１０℃／ｍｉｎの昇・降温スピードにより昇温、降温、昇温を繰り返し、２回目の昇温時のＤＳＣ曲線の融解ピーク温度を融点とした。また、融解ピークが２つ以上ある場合は、低い側のピーク温度を融点とした。
<Melting point>
Measured by the method described in JIS K7122: 1987 "Method for measuring the transition heat of plastic". That is, using a differential scanning calorimeter DSC220 type (manufactured by Seiko Denshi Kogyo Co., Ltd.), 7 mg of a sample was filled in a measurement container, and a nitrogen gas flow rate of 30 ml / min was used at a temperature between room temperature and 220 ° C. to 10 ° C./min. The temperature was raised, lowered, and raised repeatedly at the speed of raising and lowering the temperature, and the melting peak temperature of the DSC curve at the second temperature raising was defined as the melting point. When there are two or more melting peaks, the lower peak temperature is taken as the melting point.
＜嵩密度＞
予備発泡粒子の嵩密度は下記の要領で測定した。
まず、予備発泡粒子を５００ｃｍ３、メスシリンダ内に５００ｃｍ３の目盛りまで充填した。なお、メスシリンダを水平方向から目視し、予備発泡粒子が一粒でも５００ｃｍ３の目盛りに達しているものがあれば、その時点で予備発泡粒子のメスシリンダ内への充填を終了した。
次に、メスシリンダ内に充填した予備発泡粒子の質量を小数点以下２位の有効数字で秤量し、その質量をＷ（ｇ）とした。
そして、下記の式により予備発泡粒子の嵩密度を算出した。
嵩密度（ｇ／ｃｍ３）＝Ｗ／５００
＜嵩発泡倍数＞
予備発泡粒子の嵩発泡倍数は、次式により算出した。
嵩発泡倍数（倍）＝１／密度（ｇ／ｃｍ３）
<Bulk density>
The bulk density of the pre-expanded particles was measured as follows.
First, pre-expanded particles were filled up to 500 cm 3 and a graduation of 500 cm 3 in a measuring cylinder. When the graduated cylinder was visually observed from the horizontal direction and any pre-expanded particles reached the scale of 500 cm 3 , the filling of the pre-expanded particles into the graduated cylinder was completed at that point.
Next, the mass of the pre-expanded particles filled in the measuring cylinder was weighed with two significant figures after the decimal point, and the mass was defined as W (g).
And the bulk density of the pre-expanded particles was calculated by the following formula.
Bulk density (g / cm 3 ) = W / 500
<Bulk foam multiple>
The bulk expansion ratio of the pre-expanded particles was calculated by the following formula.
Bulk foam multiple (times) = 1 / density (g / cm 3 )
＜密度＞
発泡成形体の密度は下記の要領で測定した。
ＪＩＳ Ｋ７１２２：１９９９「発泡プラスチック及びゴム−見掛け密度の測定」記載の方法で測定した。
５０ｃｍ３以上（半硬質および軟質材料の場合は１００ｃｍ３以上）の試験片を材料の元のセル構造を変えない様に切断し、その質量を測定し、次式により算出した。
密度（ｇ／ｃｍ３）＝試験片質量（ｇ）／試験片体積（ｃｍ３）
試験片状態調節、測定用試験片は、成形後７２時間以上経過した試料から切り取り、２３℃±２℃×５０％±５％または２７℃±２℃×６５％±５％の雰囲気条件に１６時間以上放置したものである。
＜発泡倍数＞
発泡成形体の発泡倍数は、次式により算出した。
発泡倍数（倍）＝１／密度（ｇ／ｃｍ３）
<Density>
The density of the foamed molded product was measured as follows.
It was measured by the method described in JIS K7122: 1999 “Foamed Plastics and Rubbers—Measurement of Apparent Density”.
A test piece of 50 cm 3 or more (100 cm 3 or more in the case of semi-rigid and soft materials) was cut so as not to change the original cell structure of the material, its mass was measured, and calculated by the following formula.
Density (g / cm 3 ) = Test piece mass (g) / Test piece volume (cm 3 )
Test piece condition adjustment and measurement test pieces were cut out from samples that had passed 72 hours or more after molding, and were subjected to atmospheric conditions of 23 ° C. ± 2 ° C. × 50% ± 5% or 27 ° C. ± 2 ° C. × 65% ± 5%. It has been left for more than an hour.
<Foaming multiple>
The expansion ratio of the foamed molded product was calculated by the following formula.
Foaming multiple (times) = 1 / density (g / cm 3 )
＜加熱寸法変化率＞
加熱寸法変化率はＪＩＳ Ｋ ６７６７：１９９９Ｋ「発泡プラスチック−ポリエチレン−試験方法」記載のＢ法にて測定した。
試験片は１５０×１５０×原厚み（ｍｍ）として、その中央部に縦および横方向にそれぞれ互いに平行に３本の直線を５０ｍｍ間隔になるよう記入し、８５℃の熱風循環式乾燥機の中に１６８時間置いた後に取出し、標準状態の場所に１時間放置後、縦および横線の寸法を下記式によって測定した。
Ｓ＝（Ｌ１−Ｌ０）／Ｌ０×１００
式中、Ｓは加熱寸法変化率（％）、Ｌ１は加熱後の平均寸法（ｍｍ）、Ｌ０は初めの平均寸法（ｍｍ）をそれぞれ表す。
加熱寸法変化率Ｓの評価基準は、絶対値で１％以下が○、１％より大きい場合を×とする。
<Heating dimensional change rate>
The heating dimensional change rate was measured by the method B described in JIS K 6767: 1999K “foamed plastic-polyethylene test method”.
The test piece is 150 x 150 x original thickness (mm), and three straight lines are written in the center in parallel with each other in the vertical and horizontal directions at intervals of 50 mm. The sample was taken out after 168 hours and left in a standard state for 1 hour, and the vertical and horizontal line dimensions were measured by the following formulas.
S = (L1-L0) / L0 × 100
In the formula, S represents a heating dimensional change rate (%), L1 represents an average dimension (mm) after heating, and L0 represents an initial average dimension (mm).
The evaluation standard of the heating dimensional change rate S is ◯ when 1% or less in absolute value is greater than 1%.
＜耐薬品性＞
発泡成形体から縦１００ｍｍ×横１００ｍｍ×厚み２０ｍｍの平面長方形状の板状試験片を切り出し、２３℃、湿度５０％の条件下で２４時間放置した。なお、試験片の上面全面が発泡成形体の表面から形成されるように試験片を発泡成形体から切り出した。
次に、薬品としてガソリン１ｇを均一に塗布し、２３℃、湿度５０％の条件で６０分放置した。
その後、試験片の上面から薬品を拭き取り、試験片の上面を目視観察して下記基準に基づいて判断した。
○：良好 変化なし
△：やや悪い 表面軟化
×：悪い 表面陥没（収縮）
<Chemical resistance>
A flat rectangular plate-shaped test piece having a length of 100 mm, a width of 100 mm, and a thickness of 20 mm was cut out from the foamed molded article and allowed to stand at 23 ° C. and a humidity of 50% for 24 hours. The test piece was cut out from the foam molded body so that the entire upper surface of the test piece was formed from the surface of the foam molded body.
Next, 1 g of gasoline as a chemical was uniformly applied and left for 60 minutes at 23 ° C. and 50% humidity.
Then, the chemical | medical agent was wiped off from the upper surface of the test piece, the upper surface of the test piece was observed visually, and it judged based on the following reference | standard.
○: Good No change
Δ: Slightly poor surface softening
×: Bad surface depression (shrinkage)
＜黒色度＞
色合いの評価として、成形体表面層のＬ値を、ＪＩＳ Ｚ８７２２「色の測定方法‐反射及び透過物体色」に準拠した反射法にて、分光式色彩計（日本電色工業社製）を用いて測定した。
なお、測定面積を３０ｍｍφ（ＪＩＳは５０ｍｍΦ）とした。
上記Ｌ値の測定結果より、黒色度の評価を以下のようにして行った。
○：Ｌ値が０以上２０以下である。
△：Ｌ値が２０を超え２５以下である。
×：Ｌ値が２５を超え１００以下である。
<Blackness>
For the evaluation of hue, the spectroscopic colorimeter (manufactured by Nippon Denshoku Industries Co., Ltd.) was used for the L value of the surface layer of the molded product by a reflection method in accordance with JIS Z8722 “Color Measurement Method-Reflection and Transmission Object Color”. Measured.
The measurement area was 30 mmφ (JIS is 50 mmφ).
From the measurement result of the L value, the blackness was evaluated as follows.
A: L value is 0 or more and 20 or less.
(Triangle | delta): L value exceeds 20 and is 25 or less.
X: L value exceeds 25 and is 100 or less.
＜粒子中心部または表層の吸光度比とポリスチレン系樹脂比率＞
吸光度比（Ｄ６９８／Ｄ１３７６）は下記の要領で測定した。
すなわち、無作為に選択した１０個の各予備発泡粒子の粒子中心部または表面を、ＡＴＲ法赤外分光分析を行なって赤外線吸収スペクトルを得た。
ここで、粒子中心部の測定では、各予備発泡粒子を二等分（例えば、粒径５ｍｍの予備発泡粒子を２．５±０．５ｍｍに切断する。）し、さらにその切断面の中心（少なくとも円の中心から１／４より内側）にＡＴＲプリズムを密着させて測定した。
また、表面の測定では、各予備発泡粒子の表面にＡＴＲプリズムを密着させて測定する。
各赤外線吸収スペクトルから吸光度比（Ｄ６９８／Ｄ１３７６）をそれぞれ算出し、最小の吸光度比と最大の吸光度比を除外した。そして、残余の８個の吸光度比の相加平均を吸光度比（Ｄ６９８／Ｄ１３７６）とした。なお、吸光度比（Ｄ６９８／Ｄ１３７６）は、例えば、Ｎｉｃｏｌｅｔ社（現在の社名：Ｔｈｅｒｍｏｆｉｓｈｅｒ社）から商品名「フーリエ変換赤外分光光度計 ＭＡＧＭＡ５６０」で販売されている測定装置を用いて測定した。
ポリスチレン系樹脂比率（質量％）は、既知混合比の標準品を用いて予め作成した検量線に基づいて、吸光度比（Ｄ６９８／Ｄ１３７６）から算出した。
<Absorbance ratio of the particle center or surface layer and polystyrene resin ratio>
The absorbance ratio (D698 / D1376) was measured as follows.
That is, an infrared absorption spectrum was obtained by performing ATR infrared spectroscopic analysis on the particle central part or surface of each of 10 randomly selected pre-expanded particles.
Here, in the measurement of the particle center, each pre-expanded particle is divided into two equal parts (for example, pre-expanded particles having a particle size of 5 mm are cut into 2.5 ± 0.5 mm), and the center of the cut surface ( The measurement was performed with the ATR prism in close contact with at least the inner side of the circle from the center of the circle.
In the measurement of the surface, the ATR prism is closely attached to the surface of each pre-expanded particle.
The absorbance ratio (D698 / D1376) was calculated from each infrared absorption spectrum, and the minimum absorbance ratio and the maximum absorbance ratio were excluded. The arithmetic average of the remaining 8 absorbance ratios was taken as the absorbance ratio (D698 / D1376). The absorbance ratio (D698 / D1376) was measured, for example, using a measuring apparatus sold under the trade name “Fourier transform infrared spectrophotometer MAGMA 560” from Nicolet (current name: Thermofisher).
The polystyrene resin ratio (% by mass) was calculated from the absorbance ratio (D698 / D1376) based on a calibration curve prepared in advance using a standard product having a known mixing ratio.
＜粒子全体の吸光度比とポリスチレン系樹脂比率＞
吸光度比（Ｄ６９８／Ｄ１３７６）は下記の要領で測定した。
すなわち、予備発泡粒子を加熱温度２００℃〜２５０℃で加熱減容し、冷却した後に粉砕し、粉砕物を２ｇ精秤した。
この粉砕物を小型射出成形機にて下記条件下に加熱混練して、直径が２５ｍｍでかつ高さが２ｍｍの円柱状に成形することによって測定試料を得た。
なお、小型射出成形機としては、例えば、ＣＳＩ社から商品名「ＣＳ−１８３」で販売されているものを用いた。
射出成形条件：加熱温度２００℃〜２５０℃、混練時間１０分
測定試料の表面を、ＡＴＲ法赤外分光分析を行なって赤外吸収スペクトルを得た。
各赤外吸収スペクトルから吸光度比（Ｄ６９８／Ｄ１３７６）を算出した。なお、吸光度比（Ｄ６９８／Ｄ１３７６）は、例えば、Ｎｉｃｏｌｅｔ社（現在の社名：Ｔｈｅｒｍｏｆｉｓｈｅｒ社）から商品名「フーリエ変換赤外分光光度計 ＭＡＧＭＡ５６０」で販売されている測定装置を用いて測定した。
ポリスチレン系樹脂比率（質量％）は、既知混合比の標準品を用いて予め作成した検量線に基づいて、吸光度比（Ｄ６９８／Ｄ１３７６）から算出した。
<Absorbance ratio of whole particles and polystyrene resin ratio>
The absorbance ratio (D698 / D1376) was measured as follows.
That is, the pre-expanded particles were heated and reduced at a heating temperature of 200 ° C. to 250 ° C., cooled and pulverized, and 2 g of the pulverized product was precisely weighed.
This pulverized product was heated and kneaded under the following conditions with a small injection molding machine, and formed into a cylindrical shape having a diameter of 25 mm and a height of 2 mm to obtain a measurement sample.
As the small injection molding machine, for example, a machine sold by CSI under the trade name “CS-183” was used.
Injection molding conditions: heating temperature 200 ° C. to 250 ° C., kneading time 10 minutes
The surface of the measurement sample was subjected to ATR infrared spectroscopic analysis to obtain an infrared absorption spectrum.
The absorbance ratio (D698 / D1376) was calculated from each infrared absorption spectrum. The absorbance ratio (D698 / D1376) was measured, for example, using a measuring apparatus sold under the trade name “Fourier transform infrared spectrophotometer MAGMA 560” from Nicolet (current name: Thermofisher).
The polystyrene resin ratio (% by mass) was calculated from the absorbance ratio (D698 / D1376) based on a calibration curve prepared in advance using a standard product having a known mixing ratio.
＜燃焼速度＞
燃焼速度は、米国自動車安全基準ＦＭＶＳＳ ３０２に準拠した方法で測定した。
試験片は、発泡倍数３０倍、３５０ｍｍ×１００ｍｍ×１２ｍｍ（厚み）とし、少なくとも３５０ｍｍ×１００ｍｍの二面には表皮が存在するものとした。
発泡倍数３０倍の発泡成形体において燃焼速度が８０ｍｍ／ｍｉｎ以下であれば自動車室内の構造部材として良好に用いることができるので、燃焼速度は、以下の基準で評価した。
○：燃焼速度８０ｍｍ／ｍｉｎ以下であり良好である。
×：燃焼速度８０ｍｍ／ｍｉｎを超えており不良である。
<Burning rate>
The burning rate was measured by a method in accordance with US automobile safety standard FMVSS 302.
The test piece had an expansion ratio of 30 times, 350 mm × 100 mm × 12 mm (thickness), and a skin was present on at least two sides of 350 mm × 100 mm.
In a foamed molded article having a foaming ratio of 30 times, if the combustion rate is 80 mm / min or less, it can be satisfactorily used as a structural member in an automobile interior. Therefore, the combustion rate was evaluated according to the following criteria.
○: The combustion speed is 80 mm / min or less, which is good.
X: The combustion speed exceeds 80 mm / min, which is defective.
＜予備発泡粒子の発泡性評価＞
予備発泡工程において嵩発泡倍数３０倍に予備発泡するまでの加熱時間から、予備発泡機缶内に導入する水蒸気のゲージ圧力における予備発泡粒子の発泡性の評価を行った。発泡性は以下の基準で評価した。
○：予備発泡工程における加熱時間：２０〜１８０秒以下
×：予備発泡工程における加熱時間：１８０秒より長い、または嵩発泡倍数３０倍まで発泡しない
<Evaluation of foamability of pre-expanded particles>
The foaming property of the pre-foamed particles at the gauge pressure of water vapor introduced into the pre-foaming machine can was evaluated from the heating time until the pre-foaming step was performed to 30 times the bulk foaming ratio. The foamability was evaluated according to the following criteria.
○: Heating time in the pre-foaming step: 20 to 180 seconds or less X: Heating time in the pre-foaming step: longer than 180 seconds or not foaming up to 30 times the bulk foaming ratio
＜予備発泡粒子の最表層膜厚の測定＞
測定装置として走査電子顕微鏡ＪＳＭ−６３６０ＬＶ（日本電気社製）を用いた。
予備発泡粒子の中から任意に選択した１０個について、剃刀刃を用いて、それぞれ粒子の中心を通る平面で二等分し、その一方の切断面の最表層部を走査型電子顕微鏡を用いて、５００倍に拡大した画像を作成した（図１、図３及び図５参照）。その後、測長機能を用いて最外にある非発泡層に任意に１５点線を引き、厚みを測定した。各画像について、同様に測定し、計１０画像分の平均値を最表層膜厚とした。
<Measurement of outermost layer thickness of pre-expanded particles>
A scanning electron microscope JSM-6360LV (manufactured by NEC Corporation) was used as a measuring device.
About 10 arbitrarily selected from the pre-expanded particles, razor blades are used to bisect each of the planes passing through the center of each particle, and the outermost layer portion of one of the cut surfaces is scanned using a scanning electron microscope. An image magnified 500 times was created (see FIGS. 1, 3 and 5). Thereafter, a 15-dot line was arbitrarily drawn on the outermost non-foamed layer using the length measurement function, and the thickness was measured. Each image was measured in the same manner, and the average value for a total of 10 images was defined as the outermost layer thickness.
＜予備発泡粒子最表層の気泡径の測定＞
測定装置として走査電子顕微鏡ＪＳＭ−６３６０ＬＶ（日本電気社製）を用いた。
予備発泡粒子の中から任意に選択した１０個について、剃刀刃を用いて、それぞれ粒子の中心を通る平面で二等分し、その一方の切断面の表層部を走査型電子顕微鏡を用いて、２０倍（場合により１００倍）に拡大した画像を撮影した。
次に、撮影した画像をＡ４用紙上に１画像づつ印刷した。印刷された画像から、最表層に接している気泡を通る曲線の長さ（線長）と最表層に接している気泡数を計測した。
計測結果から下記式により気泡の平均弦長（t）を算出した。
平均弦長 ｔ＝線長／（気泡数×写真の倍率）
また、２０倍に拡大した写真から気泡数を計測することが困難な場合は、前記と同様に予備発泡粒子を二等分し、その一方の切断面を切断面の中心を通る直線で等しく四分割（場合により八分割）した箇所で１００倍にした画像を撮影し、前記と同様にそれぞれ最表層に接している気泡を通る曲線の長さ（線長）と最表層に接している気泡数を計測し、計四分割（場合により八分割）分の画像の平均値を算出した。そして、前記と同様に気泡の平均弦長（t）を算出した。
そして平均弦長（t）を用いて、次式により予備発泡粒子の断面の最表層に接している気泡の気泡径（Ｄ）を算出した。
Ｄ＝ｔ／０.６１６
さらにそれらの算術平均を予備発泡粒子の断面の最表層に接している気泡の平均気泡径とした。
<Measurement of bubble diameter of outermost layer of pre-expanded particles>
A scanning electron microscope JSM-6360LV (manufactured by NEC Corporation) was used as a measuring device.
About 10 arbitrarily selected from the pre-foamed particles, using a razor blade, each bisected by a plane passing through the center of the particle, the surface layer portion of one of the cut surfaces using a scanning electron microscope, Images magnified 20 times (in some cases 100 times) were taken.
Next, the captured images were printed one by one on A4 paper. From the printed image, the length (line length) of the curve passing through the bubbles in contact with the outermost layer and the number of bubbles in contact with the outermost layer were measured.
From the measurement result, the average chord length (t) of the bubbles was calculated by the following formula.
Average chord length t = Line length / (Number of bubbles x Photo magnification)
If it is difficult to measure the number of bubbles from a photograph magnified 20 times, the pre-expanded particles are divided into two equal parts as described above, and one of the cut surfaces is equally divided by four straight lines passing through the center of the cut surface. Take a 100x image at the divided (in some cases divided into eight) parts, and in the same way as above, the length of the curve (line length) passing through the bubbles in contact with the outermost layer and the number of bubbles in contact with the outermost layer Was measured, and the average value of the image for a total of four divisions (in some cases eight divisions) was calculated. Then, the average chord length (t) of the bubbles was calculated in the same manner as described above.
Then, using the average chord length (t), the bubble diameter (D) of the bubbles in contact with the outermost layer of the cross-section of the pre-expanded particles was calculated by the following formula.
D = t / 0.616
Furthermore, the arithmetic average of them was defined as the average bubble diameter of bubbles in contact with the outermost surface layer of the cross-section of the pre-expanded particles.
＜カーボンの配合量＞
測定装置として、示差熱・熱量同時測定装置 ＴＧ／ＤＴＡ６２００型（エスアイアイ・ナノテクノロジー社製）を用い、ＪＩＳ Ｋ７０７５「炭素繊維強化プラスチックの繊維含有率及び空洞率試験方法（燃焼法）」に準拠して測定を行った。
測定試料量を１５ｍｇとして、５２０℃〜８００℃昇温時（加熱速度１０℃／ｍｉｎ）の減量分をカーボン量として算術計算した。
<Carbon content>
TG / DTA6200 type (manufactured by SII Nanotechnology Co., Ltd.) is used as the measuring device, and conforms to JIS K7075 “Testing method for fiber content and void ratio of carbon fiber reinforced plastic (combustion method)” And measured.
The amount of the sample to be measured was 15 mg, and the amount of decrease during heating at 520 ° C. to 800 ° C. (heating rate 10 ° C./min) was calculated as the amount of carbon.
［実施例１］
ポリプロピレン系樹脂（プライムポリマー社製、商品名「Ｆ−７４４ＮＰ」、融点：１４０℃）１９２０ｇと、ファーネスブラック（三菱化学社製、商品名「＃９００」）８０ｇを混合し、この混合物を押出機に供給して溶融混練してストランドカットにより造粒ペレット化することにより、ポリプロピレン系樹脂に、ファーネスブラックを４質量％含有させた球状（卵状）のカーボン含有ポリプロピレン系樹脂粒子を得た。
このときのカーボン含有ポリプロピレン系樹脂粒子を１００粒あたり８０ｍｇ、平均粒子径約１ｍｍに調整した。
次に、撹拌機付５Ｌオートクレーブに、前記カーボン含有ポリプロピレン系樹脂粒子８００ｇを入れ、水性媒体として純水２ｋｇ、ピロリン酸マグネシウム２０ｇ、ドデシルベンゼンスルホン酸ソーダ０．５ｇを加え、撹拌して水性媒体中に懸濁させ、１０分間保持し、その後６０℃に昇温して水系懸濁液とした。
次に、この懸濁液中にジクミルパーオキサイド０．７ｇを溶解させたスチレン単量体３４０ｇを３０分で滴下した。滴下後３０分保持し、カーボン含有ポリプロピレン系樹脂粒子にスチレン単量体を吸収させた。
次に、反応系の温度をカーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点と同じ１４０℃に昇温して２時間保持し、スチレン単量体をカーボン含有ポリプロピレン系樹脂粒子中で重合（第１の重合）させた。
次に、第１の重合の反応液をカーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点より２０℃低い１２０℃にして、この懸濁液中に、ドデシルベンゼンスルホン酸ソーダ１．５ｇを加えた後、重合開始剤としてジクミルパーオキサイド３．６ｇを溶解したスチレン単量体８６０ｇを４時間かけて滴下し、カーボン含有ポリプロピレン系樹脂粒子に吸収させながら重合（第２の重合）を行った。
この滴下終了後、１２０℃で１時間保持した後に１４０℃に昇温し３時間保持して重合を完結し、カーボン含有改質ポリスチレン系樹脂粒子を得た。
その後、反応系の温度を６０℃にして、この懸濁液中に、難燃剤としてトリ（２，３−ジブロモプロピル）イソシアネート（日本化成社製）６０ｇと、難燃助剤として２，３−ジメチル−２，３−ジフェニルブタン（化薬アクゾ社製）３０ｇとを投入し、投入後、反応系の温度を１４０℃に昇温し、４時間攪拌を続け、カーボン含有改質ポリスチレン系樹脂粒子を得た。
次に、常温まで冷却し、カーボン含有改質ポリスチレン系樹脂粒子を５Ｌオートクレーブから取り出した。取り出し後のカーボン含有改質ポリスチレン系樹脂粒子２ｋｇと水２Ｌを再び撹拌機付５Ｌオートクレーブに投入し、発泡剤としてブタン３００ｇを撹拌機付５Ｌオートクレーブに注入した。注入後、７０℃に昇温し、４時間撹拌を続けた。
その後、常温まで冷却して５Ｌオートクレーブから取り出し、脱水乾燥した後に発泡性カーボン含有改質ポリスチレン系樹脂粒子を得た。
次に、得られた発泡性カーボン含有改質ポリスチレン系樹脂粒子を笠原工業株式会社製ＰＳＸ４０予備発泡機に１０００ｇ投入し、ＰＳＸ４０予備発泡機缶内にゲージ圧力０．００５ＭＰａの水蒸気を導入して加熱し、嵩発泡倍数３０倍に予備発泡させ、予備発泡粒子を得た。
そして、得られた予備発泡粒子を用いて、吸光度の測定を行い、ポリスチレン系樹脂比率を算出した。また、得られた予備発泡粒子を用いて、走査型電子顕微鏡にて最表層の平均膜厚および最表層の平均気泡径の測定を行った。
さらに、得られた予備発泡粒子を１日間室温に放置した後、４００ｍｍ×３００ｍｍ×５０ｍｍの大きさのキャビティを有する成形型の該キャビティ内に充填し、成形型に０．２５ＭＰａの水蒸気を５０秒間導入して加熱し、その後、発泡成形体の最高面圧が０．００１ＭＰａに低下するまで冷却して、発泡成形体を得た。
この成形条件により外観、融着とも良好な発泡成形体を得た。
そして、得られたカーボン含有改質ポリスチレン系樹脂発泡成形体を用いて、発泡倍数、加熱寸法変化率、耐薬品性、黒色度の測定を行った。
[Example 1]
Polypropylene resin (manufactured by Prime Polymer Co., Ltd., trade name “F-744NP”, melting point: 140 ° C.) 1920 g and furnace black (Mitsubishi Chemical Co., Ltd., trade name “# 900”) 80 g were mixed, and this mixture was extruded. , Melt-kneaded, and pelletized by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene resin particles containing 4% by mass of furnace black in polypropylene resin.
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
Next, 800 g of the carbon-containing polypropylene resin particles are put into a 5 L autoclave with a stirrer, and 2 kg of pure water, 20 g of magnesium pyrophosphate, and 0.5 g of sodium dodecylbenzenesulfonate are added as an aqueous medium, and the mixture is stirred and mixed in an aqueous medium. And then kept for 10 minutes, and then heated to 60 ° C. to obtain an aqueous suspension.
Next, 340 g of a styrene monomer in which 0.7 g of dicumyl peroxide was dissolved in this suspension was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 140 ° C. which is the same as the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles and held for 2 hours, and the styrene monomer is polymerized in the carbon-containing polypropylene resin particles ( First polymerization).
Next, the reaction liquid of the first polymerization is set to 120 ° C. which is 20 ° C. lower than the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles, and 1.5 g of sodium dodecylbenzenesulfonate is added to this suspension. Then, 860 g of a styrene monomer in which 3.6 g of dicumyl peroxide was dissolved as a polymerization initiator was dropped over 4 hours, and polymerization (second polymerization) was performed while absorbing the carbon-containing polypropylene resin particles. .
After completion of the dropping, the mixture was held at 120 ° C. for 1 hour, then heated to 140 ° C. and held for 3 hours to complete the polymerization, thereby obtaining carbon-containing modified polystyrene resin particles.
Thereafter, the temperature of the reaction system was set to 60 ° C., and 60 g of tri (2,3-dibromopropyl) isocyanate (manufactured by Nippon Kasei Co., Ltd.) as a flame retardant and 2,3- 30 g of dimethyl-2,3-diphenylbutane (manufactured by Kayaku Akzo) was added. After the addition, the temperature of the reaction system was raised to 140 ° C., and stirring was continued for 4 hours. Got.
Next, it was cooled to room temperature, and the carbon-containing modified polystyrene resin particles were taken out from the 5 L autoclave. 2 kg of carbon-containing modified polystyrene resin particles and 2 L of water after taking out were again put into a 5 L autoclave with a stirrer, and 300 g of butane as a blowing agent was injected into a 5 L autoclave with a stirrer. After the injection, the temperature was raised to 70 ° C. and stirring was continued for 4 hours.
Then, it cooled to normal temperature, took out from the 5L autoclave, dehydrated and dried, and then obtained expandable carbon-containing modified polystyrene resin particles.
Next, 1000 g of the obtained expandable carbon-containing modified polystyrene resin particles obtained is put into a PSX40 pre-foaming machine manufactured by Kasahara Kogyo Co., Ltd., and steam is introduced into the PSX40 pre-foaming machine can by introducing water vapor with a gauge pressure of 0.005 MPa. And pre-expanded to a bulk expansion ratio of 30 times to obtain pre-expanded particles.
And the light absorbency was measured using the obtained pre-expanded particle | grains, and the polystyrene-type resin ratio was computed. Moreover, the average film thickness of the outermost layer and the average cell diameter of the outermost layer were measured with a scanning electron microscope using the obtained pre-expanded particles.
Further, the pre-expanded particles obtained were left at room temperature for 1 day, and then filled in the cavity of a mold having a size of 400 mm × 300 mm × 50 mm, and 0.25 MPa of water vapor was added to the mold for 50 seconds. It was introduced and heated, and then cooled until the maximum surface pressure of the foamed molded product was reduced to 0.001 MPa to obtain a foamed molded product.
Under these molding conditions, a foamed molded article having good appearance and fusion was obtained.
Then, using the obtained carbon-containing modified polystyrene resin foam molded article, the expansion ratio, the heating dimensional change rate, the chemical resistance, and the blackness were measured.
［実施例２］
実施例１と同様にして形成した発泡性カーボン含有改質ポリスチレン系樹脂粒子を、ゲージ圧力０．０４ＭＰａの水蒸気で予備発泡したこと以外は実施例１と同様にして、発泡成形体を作製した。
[Example 2]
A foamed molded article was produced in the same manner as in Example 1 except that foamable carbon-containing modified polystyrene resin particles formed in the same manner as in Example 1 were pre-foamed with water vapor having a gauge pressure of 0.04 MPa.
［実施例３］
実施例１と同様にして形成した発泡性カーボン含有改質ポリスチレン系樹脂粒子を、ゲージ圧力０．０９ＭＰａの水蒸気で予備発泡したこと以外は実施例１と同様にして、発泡成形体を作製した。
[Example 3]
A foamed molded article was produced in the same manner as in Example 1 except that foamable carbon-containing modified polystyrene resin particles formed in the same manner as in Example 1 were pre-foamed with water vapor having a gauge pressure of 0.09 MPa.
［実施例４］
難燃剤としてトリ（２，３−ジブロモプロピル）イソシアネート（日本化成社製）５０ｇと、難燃助剤として２，３−ジメチル−２，３−ジフェニルブタン（化薬アクゾ社製）１０ｇとを投入したこと以外は、実施例２と同様にして、発泡成形体を作製した。
[Example 4]
50 g of tri (2,3-dibromopropyl) isocyanate (manufactured by Nippon Kasei Co., Ltd.) as a flame retardant and 10 g of 2,3-dimethyl-2,3-diphenylbutane (made by Kayaku Akzo) as a flame retardant aid A foamed molded article was produced in the same manner as in Example 2 except that.
［実施例５］
嵩発泡倍数２０倍の予備発泡粒子を得たこと以外は、実施例４と同様にして、発泡成形体を作製した。
[Example 5]
A foamed molded article was produced in the same manner as in Example 4 except that the pre-expanded particles having a bulk expansion ratio of 20 times were obtained.
［実施例６］
嵩発泡倍数４０倍の予備発泡粒子を得たこと以外は、実施例４と同様にして、発泡成形体を作製した。
[Example 6]
A foamed molded article was produced in the same manner as in Example 4 except that the pre-expanded particles having a bulk expansion ratio of 40 times were obtained.
［実施例７］
ポリプロピレン系樹脂（プライムポリマー社製、商品名「Ｆ−７４４ＮＰ」、融点：１４０℃）１８９４ｇと、ファーネスブラック（三菱化学社製、商品名「＃９００」）１０６ｇを混合し、この混合物を押出機に供給して溶融混練してストランドカットにより造粒ペレット化することにより、ポリプロピレン系樹脂に、ファーネスブラックを５．３質量％含有させた球状（卵状）のカーボン含有ポリプロピレン系樹脂粒子を得た。
このときのカーボン含有ポリプロピレン系樹脂粒子を１００粒あたり８０ｍｇ、平均粒子径約１ｍｍに調整した。
前記カーボン含有ポリプロピレン系樹脂粒子６００ｇを攪拌機付５Ｌオートクレーブに入れ、水性媒体として純水２ｋｇ、前記分散剤２０ｇ、前記界面活性剤０．５ｇを加え、攪拌して水性媒体中に懸濁させ、１０分間保持し、その後６０℃に昇温して水系懸濁液とした。
この懸濁液中に、前記重合開始剤０．５ｇを溶解させたスチレン単量体２５０ｇを３０分で滴下した。滴下後３０分保持し、カーボン含有ポリプロピレン系樹脂粒子にスチレン単量体を吸収させた。
次に、反応系の温度をカーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点と同じ１４０℃に昇温して２時間保持し、スチレン単量体をカーボン含有ポリプロピレン系樹脂粒子中で重合（第１の重合）させた。
第１重合段階の反応液をカーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点より２０℃低い１２０℃にして、この懸濁液中に、前記界面活性剤１．５ｇを加えた後、重合開始剤４．２ｇを溶解したスチレン単量体１１５０ｇを５．５時間かけて滴下し、カーボン含有ポリプロピレン系樹脂粒子に吸収させながら重合を行った。
この滴下終了後、１２０℃で１時間保持した後に１４０℃に昇温し３時間保持して重合を完結し（第２重合段階）、カーボン含有改質ポリスチレン系樹脂粒子を得た。
その後、反応系の温度を６０℃にして、この懸濁液中に、前記難燃剤６０ｇと、前記難燃助剤３０ｇを投入し、投入後、反応系の温度を１４０℃に昇温し、４時間攪拌を続け、カーボン含有改質ポリスチレン系樹脂粒子を得た。
このカーボン含有改質ポリスチレン系樹脂粒子を用いたこと以外は、実施例２と同様にして、発泡成形体を作製した。
[Example 7]
1894 g of polypropylene resin (manufactured by Prime Polymer, trade name “F-744NP”, melting point: 140 ° C.) and 106 g of furnace black (trade name “# 900”, manufactured by Mitsubishi Chemical Corporation) were mixed, and this mixture was extruded , Melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-shaped) carbon-containing polypropylene resin particles containing 5.3% by mass of furnace black in polypropylene resin. .
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
600 g of the carbon-containing polypropylene resin particles are placed in a 5 L autoclave with a stirrer, 2 kg of pure water, 20 g of the dispersant, and 0.5 g of the surfactant are added as an aqueous medium, and the mixture is stirred and suspended in the aqueous medium. The mixture was held for 1 minute, and then heated to 60 ° C. to obtain an aqueous suspension.
In this suspension, 250 g of a styrene monomer in which 0.5 g of the polymerization initiator was dissolved was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 140 ° C. which is the same as the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles and held for 2 hours, and the styrene monomer is polymerized in the carbon-containing polypropylene resin particles ( First polymerization).
The reaction liquid in the first polymerization stage is set to 120 ° C., which is 20 ° C. lower than the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles, and 1.5 g of the surfactant is added to the suspension, followed by polymerization. Polymerization was performed while 1150 g of a styrene monomer in which 4.2 g of an initiator was dissolved was dropped over 5.5 hours and absorbed in carbon-containing polypropylene resin particles.
After completion of the dropping, the temperature was maintained at 120 ° C. for 1 hour, then heated to 140 ° C. and maintained for 3 hours to complete the polymerization (second polymerization stage), and carbon-containing modified polystyrene resin particles were obtained.
Thereafter, the temperature of the reaction system was set to 60 ° C., 60 g of the flame retardant and 30 g of the flame retardant aid were added to this suspension, and after the addition, the temperature of the reaction system was increased to 140 ° C. Stirring was continued for 4 hours to obtain carbon-containing modified polystyrene resin particles.
A foam molded article was produced in the same manner as in Example 2 except that the carbon-containing modified polystyrene resin particles were used.
［実施例８］
ポリプロピレン系樹脂（プライムポリマー社製、商品名「Ｆ−７４４ＮＰ」、融点：１４０℃）１９３６ｇと、ファーネスブラック（三菱化学社製、商品名「＃９００」）６４ｇを混合し、この混合物を押出機に供給して溶融混練してストランドカットにより造粒ペレット化することにより、ポリプロピレン系樹脂に、ファーネスブラックを３．２質量％含有させた球状（卵状）のカーボン含有ポリプロピレン系樹脂粒子を得た。
このときのカーボン含有ポリプロピレン系樹脂粒子を１００粒あたり８０ｍｇ、平均粒子径約１ｍｍに調整した。
前記カーボン含有ポリプロピレン系樹脂粒子１０００ｇを攪拌機付５Ｌオートクレーブに入れ、水性媒体として純水２ｋｇ、前記分散剤２０ｇ、前記界面活性剤０．５ｇを加え、攪拌して水性媒体中に懸濁させ、１０分間保持し、その後６０℃に昇温して水系懸濁液とした。
この懸濁液中に、前記重合開始剤０．８ｇを溶解させたスチレン単量体４２０ｇを３０分で滴下した。滴下後３０分保持し、カーボン含有ポリプロピレン系樹脂粒子にスチレン単量体を吸収させた。
次に、反応系の温度をカーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点と同じ１４０℃に昇温して２時間保持し、スチレン単量体をカーボン含有ポリプロピレン系樹脂粒子中で重合（第１の重合）させた。
第１重合段階の反応液をカーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点より２０℃低い１２０℃にして、この懸濁液中に、前記界面活性剤１．５ｇを加えた後、重合開始剤３ｇを溶解したスチレン単量体５８０ｇを２．７５時間かけて滴下し、カーボン含有ポリプロピレン系樹脂粒子に吸収させながら重合を行った。
この滴下終了後、１２０℃で１時間保持した後に１４０℃に昇温し３時間保持して重合を完結し（第２重合段階）、カーボン含有改質ポリスチレン系樹脂粒子を得た。
その後、反応系の温度を６０℃にして、この懸濁液中に、前記難燃剤６０ｇと、前記難燃助剤３０ｇを投入し、投入後、反応系の温度を１４０℃に昇温し、４時間攪拌を続け、カーボン含有改質ポリスチレン系樹脂粒子を得た。
このカーボン含有改質ポリスチレン系樹脂粒子を用いたこと以外は、実施例２と同様にして、発泡成形体を作製した。
[Example 8]
1936 g of polypropylene resin (manufactured by Prime Polymer, trade name “F-744NP”, melting point: 140 ° C.) and 64 g of furnace black (trade name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. , Melt-kneaded and granulated pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene resin particles containing 3.2% by mass of furnace black in polypropylene resin. .
The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
1000 g of the carbon-containing polypropylene resin particles are placed in a 5 L autoclave with a stirrer, 2 kg of pure water, 20 g of the dispersant, and 0.5 g of the surfactant are added as an aqueous medium, and the mixture is stirred and suspended in the aqueous medium. The mixture was held for 1 minute, and then heated to 60 ° C. to obtain an aqueous suspension.
In this suspension, 420 g of a styrene monomer in which 0.8 g of the polymerization initiator was dissolved was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 140 ° C. which is the same as the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles and held for 2 hours, and the styrene monomer is polymerized in the carbon-containing polypropylene resin particles ( First polymerization).
The reaction liquid in the first polymerization stage is set to 120 ° C., which is 20 ° C. lower than the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles, and 1.5 g of the surfactant is added to the suspension, followed by polymerization. Polymerization was performed while 580 g of a styrene monomer in which 3 g of an initiator had been dissolved was dropped over 2.75 hours and absorbed in carbon-containing polypropylene resin particles.
After completion of the dropping, the temperature was maintained at 120 ° C. for 1 hour, then heated to 140 ° C. and maintained for 3 hours to complete the polymerization (second polymerization stage), and carbon-containing modified polystyrene resin particles were obtained.
Thereafter, the temperature of the reaction system was set to 60 ° C., 60 g of the flame retardant and 30 g of the flame retardant aid were added to this suspension, and after the addition, the temperature of the reaction system was increased to 140 ° C. Stirring was continued for 4 hours to obtain carbon-containing modified polystyrene resin particles.
A foam molded article was produced in the same manner as in Example 2 except that the carbon-containing modified polystyrene resin particles were used.
［実施例９］
ポリプロピレン系樹脂（プライムポリマー社製、商品名「Ｆ−７４４ＮＰ」、融点：１４０℃）１９４０ｇと、ファーネスブラック（三菱化学社製、商品名「＃９００」）６０ｇを混合し、この混合物を押出機に供給して溶融混練してストランドカットにより造粒ペレット化することにより、ポリプロピレン系樹脂に、ファーネスブラックを３質量％含有させた球状（卵状）のカーボン含有ポリプロピレン系樹脂粒子を得たこと以外は、実施例２と同様にして、発泡成形体を作製した。
[Example 9]
1940 g of polypropylene resin (manufactured by Prime Polymer, trade name “F-744NP”, melting point: 140 ° C.) and 60 g of furnace black (trade name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. Except for obtaining spherical (egg-like) carbon-containing polypropylene-based resin particles containing 3% by mass of furnace black in polypropylene-based resin by feeding and melting and kneading into pellets by strand cutting Produced a foamed molded article in the same manner as in Example 2.
［実施例１０］
ポリプロピレン系樹脂（プライムポリマー社製、商品名「Ｆ−７４４ＮＰ」、融点：１４０℃）１８４０ｇと、ファーネスブラック（三菱化学社製、商品名「＃９００」）１６０ｇを混合し、この混合物を押出機に供給して溶融混練してストランドカットにより造粒ペレット化することにより、ポリプロピレン系樹脂に、ファーネスブラックを８質量％含有させた球状（卵状）のカーボン含有ポリプロピレン系樹脂粒子を得たこと以外は、実施例２と同様にして、発泡成形体を作製した。
[Example 10]
1840 g of a polypropylene resin (manufactured by Prime Polymer, trade name “F-744NP”, melting point: 140 ° C.) and 160 g of furnace black (trade name “# 900”, manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. Except for obtaining spherical (egg-like) carbon-containing polypropylene-based resin particles containing 8% by mass of furnace black in a polypropylene-based resin by melt-kneading, and kneading into pellets by strand cutting. Produced a foamed molded article in the same manner as in Example 2.
［比較例１］
実施例１と同様にして形成した発泡性カーボン含有改質ポリスチレン系樹脂粒子を、ゲージ圧力０.００１ＭＰａの水蒸気で予備発泡し、嵩発泡倍数１５倍の予備発泡粒子を得たこと以外は実施例１と同様にして、発泡成形体を作製した。
[Comparative Example 1]
Except that foamed carbon-containing modified polystyrene resin particles formed in the same manner as in Example 1 were pre-foamed with water vapor at a gauge pressure of 0.001 MPa to obtain pre-foamed particles with a bulk foaming factor of 15 times. In the same manner as in Example 1, a foam molded article was produced.
［比較例２］
実施例１と同様にして形成した発泡性カーボン含有改質ポリスチレン系樹脂粒子を、ゲージ圧力０．１１ＭＰａの水蒸気で予備発泡したこと以外は実施例１と同様にして、発泡成形体を作製した。
[Comparative Example 2]
A foamed molded article was produced in the same manner as in Example 1 except that foamable carbon-containing modified polystyrene resin particles formed in the same manner as in Example 1 were pre-foamed with water vapor having a gauge pressure of 0.11 MPa.
［比較例３］
嵩発泡倍数５０倍の予備発泡粒子を得たこと以外は、実施例４と同様にして、発泡成形体を作製した。
[Comparative Example 3]
A foamed molded article was produced in the same manner as in Example 4 except that pre-expanded particles having a bulk expansion ratio of 50 times were obtained.
［比較例４］
ポリプロピレン系樹脂（プライムポリマー社製、商品名「Ｆ−７４４ＮＰ」、融点：１４０℃）１６８０ｇと、ファーネスブラック（三菱化学社製、商品名「＃９００」）３２０ｇを混合し、この混合物を押出機に供給して溶融混練してストランドカットにより造粒ペレット化することにより、ポリプロピレン系樹脂に、ファーネスブラックを１６質量％含有させた球状（卵状）のカーボン含有ポリプロピレン系樹脂粒子を得た。このときのカーボン含有ポリプロピレン系樹脂粒子を１００粒あたり８０ｍｇ、平均粒子径約１ｍｍに調整した。
前記カーボン含有ポリプロピレン系樹脂粒子２００ｇを攪拌機付５Ｌオートクレーブに入れ、水性媒体として純水２ｋｇ、前記分散剤２０ｇ、前記界面活性剤０．５ｇを加え、攪拌して水性媒体中に懸濁させ、１０分間保持し、その後６０℃に昇温して水系懸濁液とした。
この懸濁液中に、前記重合開始剤０．２ｇを溶解させたスチレン単量体８０ｇを３０分で滴下した。滴下後３０分保持し、カーボン含有ポリプロピレン系樹脂粒子にスチレン単量体を吸収させた。
次に、反応系の温度をカーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点と同じ１４０℃に昇温して２時間保持し、スチレン単量体をカーボン含有ポリプロピレン系樹脂粒子中で重合（第１の重合）させた。
第１重合段階の反応液をカーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点より２０℃低い１２０℃にして、この懸濁液中に、前記界面活性剤１．５ｇを加えた後、重合開始剤５．４ｇを溶解したスチレン単量体１７２０ｇを８時間かけて滴下し、カーボン含有ポリプロピレン系樹脂粒子に吸収させながら重合を行った。
この滴下終了後、１２０℃で１時間保持した後に１４０℃に昇温し３時間保持して重合を完結し（第２重合段階）、カーボン含有改質ポリスチレン系樹脂粒子を得た。
その後、反応系の温度を６０℃にして、この懸濁液中に、前記難燃剤６０ｇと、前記難燃助剤３０ｇを投入し、投入後、反応系の温度を１４０℃に昇温し、４時間攪拌を続け、カーボン含有改質ポリスチレン系樹脂粒子を得た。
このカーボン含有改質ポリスチレン系樹脂粒子を用いたこと以外は、実施例２と同様にして、発泡成形体を作製した。
[Comparative Example 4]
1680 g of polypropylene resin (product name “F-744NP”, melting point: 140 ° C.) manufactured by Prime Polymer Co., Ltd. and 320 g of furnace black (product name “# 900” manufactured by Mitsubishi Chemical Corporation) are mixed, and this mixture is extruded. , Melt-kneaded and granulated into pellets by strand cutting to obtain spherical (egg-like) carbon-containing polypropylene resin particles containing 16% by mass of furnace black in polypropylene resin. The carbon-containing polypropylene resin particles at this time were adjusted to 80 mg per 100 particles and an average particle diameter of about 1 mm.
200 g of the carbon-containing polypropylene resin particles are placed in a 5 L autoclave with a stirrer, 2 kg of pure water, 20 g of the dispersant, and 0.5 g of the surfactant are added as an aqueous medium, and the mixture is stirred and suspended in the aqueous medium. The mixture was held for 1 minute, and then heated to 60 ° C. to obtain an aqueous suspension.
In this suspension, 80 g of a styrene monomer in which 0.2 g of the polymerization initiator was dissolved was dropped in 30 minutes. After dropping, the mixture was held for 30 minutes, and the styrene monomer was absorbed by the carbon-containing polypropylene resin particles.
Next, the temperature of the reaction system is raised to 140 ° C. which is the same as the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles and held for 2 hours, and the styrene monomer is polymerized in the carbon-containing polypropylene resin particles ( First polymerization).
The reaction liquid in the first polymerization stage is set to 120 ° C., which is 20 ° C. lower than the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles, and 1.5 g of the surfactant is added to the suspension, followed by polymerization. Polymerization was carried out while 1720 g of a styrene monomer in which 5.4 g of an initiator had been dissolved was dropped over 8 hours and absorbed in carbon-containing polypropylene resin particles.
After completion of the dropping, the temperature was maintained at 120 ° C. for 1 hour, then heated to 140 ° C. and maintained for 3 hours to complete the polymerization (second polymerization stage), and carbon-containing modified polystyrene resin particles were obtained.
Thereafter, the temperature of the reaction system was set to 60 ° C., 60 g of the flame retardant and 30 g of the flame retardant aid were added to this suspension, and after the addition, the temperature of the reaction system was increased to 140 ° C. Stirring was continued for 4 hours to obtain carbon-containing modified polystyrene resin particles.
A foam molded article was produced in the same manner as in Example 2 except that the carbon-containing modified polystyrene resin particles were used.
［比較例５］
ポリプロピレン系樹脂（プライムポリマー社製、商品名「Ｆ−７４４ＮＰ」、融点：１４０℃）１８００ｇと、ファーネスブラック（三菱化学社製、商品名「＃９００」）２００ｇを混合し、この混合物を押出機に供給して溶融混練してストランドカットにより造粒ペレット化することにより、ポリプロピレン系樹脂に、ファーネスブラックを１０質量％含有させた球状（卵状）のカーボン含有ポリプロピレン系樹脂粒子を得たこと以外は、実施例２と同様にして、発泡成形体を作製した。
[Comparative Example 5]
1800 g of polypropylene resin (product name “F-744NP”, melting point: 140 ° C., manufactured by Prime Polymer Co., Ltd.) and 200 g of furnace black (product name “# 900”, manufactured by Mitsubishi Chemical Corporation) were mixed, and this mixture was extruded. Except for obtaining spherical (egg-like) carbon-containing polypropylene-based resin particles containing 10% by mass of furnace black in a polypropylene-based resin by melting and kneading and then granulating pellets by strand cutting. Produced a foamed molded article in the same manner as in Example 2.
実施例１〜１０及び比較例１〜５の製造条件と得られたカーボン含有改質ポリスチレン系樹脂発泡粒子の各部のポリスチレン樹脂の比率（以下、ＰＳ比率と記す）の測定結果とを表１にまとめて記す。 Table 1 shows the production conditions of Examples 1 to 10 and Comparative Examples 1 to 5 and the measurement results of the ratio of polystyrene resin in each part of the obtained carbon-containing modified polystyrene resin expanded particles (hereinafter referred to as PS ratio). Put it together.
［試験１］
予備発泡工程における水蒸気のゲージ圧力が異なる予備発泡粒子を用いた発泡成形体（実施例１〜３及び比較例１，２）について、予備発泡粒子の発泡性評価、予備発泡粒子の最表層平均膜厚、予備発泡粒子の最表層の平均気泡径、カーボンの配合量、発泡成形体の黒色度及び加熱寸法変化率を測定した。結果を表２に示す。
[Test 1]
For foamed molded articles (Examples 1 to 3 and Comparative Examples 1 and 2) using prefoamed particles having different water vapor gauge pressures in the prefoaming step, evaluation of foamability of the prefoamed particles, average surface layer film of prefoamed particles The thickness, the average cell diameter of the outermost layer of the pre-expanded particles, the blending amount of carbon, the blackness of the foamed molded product, and the heating dimensional change rate were measured. The results are shown in Table 2.
表２に記した結果から、予備発泡時にゲージ圧力０．００５〜０．０９０ＭＰａの範囲で蒸気加熱した本発明に係る実施例１〜３は、良好な発泡成形体を得ることができ、得られた発泡成形体の黒色度及び加熱寸法変化率ともに良好な結果が得られた。
一方、予備発泡時のゲージ圧力を低くした比較例１は、発泡倍数１５倍以上の予備発泡粒子を得られず、またゲージ圧力を高くした比較例２は、予備発泡粒子の最表層の平均膜厚が薄く、かつ最表層の平均気泡径が小さくなり、得られた発泡成形体の黒色度が劣り、加熱寸法変化率も大きくなった。
また、本発明における所定の範囲より予備発泡粒子の最表層平均膜厚および予備発泡粒子最表層の平均気泡径が大きいものは、現段階では作製できなかった。
From the results described in Table 2, Examples 1 to 3 according to the present invention, which were steam-heated in the range of a gauge pressure of 0.005 to 0.090 MPa at the time of preliminary foaming, were able to obtain a good foamed molded product. Good results were obtained for both the blackness and the heating dimensional change rate of the foamed molded product.
On the other hand, Comparative Example 1 in which the gauge pressure at the time of pre-foaming is low cannot obtain pre-foamed particles having a foaming ratio of 15 times or more, and Comparative Example 2 in which the gauge pressure is increased is an average film of the outermost layer of the pre-foamed particles. The thickness was thin, the average cell diameter of the outermost layer was small, the blackness of the obtained foamed molded product was inferior, and the heating dimensional change rate was also large.
In addition, the outermost layer average film thickness of the pre-expanded particles and the average cell diameter of the outermost layer of the pre-expanded particles could not be produced at this stage in the present invention.
図１は、実施例１で作製した予備発泡粒子の表層の電子顕微鏡画像である。
図２は、実施例１で作製した予備発泡粒子全体の電子顕微鏡画像である。
図３は、実施例２で作製した予備発泡粒子の表層の電子顕微鏡画像である。
図４は、実施例２で作製した予備発泡粒子全体の電子顕微鏡画像である。
図５は、比較例２で作製した予備発泡粒子の表層の電子顕微鏡画像である。
図６は、比較例２で作製した予備発泡粒子全体の電子顕微鏡画像である。
これらの図１〜図６から分かるように、本発明に係る実施例１，２で作製した予備発泡粒子は、最表層の平均膜厚が５〜２５μｍの範囲に入っており、かつ最表層に接している気泡の平均気泡径が１００〜６００μｍの範囲に入っている。
一方、比較例２の予備発泡粒子は、最表層の平均膜厚が４．０μｍ程度と薄くなり、また最表層に接している気泡が小さい（平均気泡径８４μｍ）構造になっていることが分かる。
FIG. 1 is an electron microscopic image of the surface layer of pre-expanded particles produced in Example 1.
FIG. 2 is an electron microscopic image of the entire pre-expanded particles produced in Example 1.
FIG. 3 is an electron microscope image of the surface layer of the pre-expanded particles produced in Example 2.
4 is an electron microscopic image of the entire pre-expanded particles produced in Example 2. FIG.
FIG. 5 is an electron microscopic image of the surface layer of the pre-expanded particles produced in Comparative Example 2.
FIG. 6 is an electron microscope image of the entire pre-expanded particles produced in Comparative Example 2.
As can be seen from FIG. 1 to FIG. 6, the pre-expanded particles produced in Examples 1 and 2 according to the present invention have an average film thickness of the outermost layer in the range of 5 to 25 μm and The average bubble diameter of the bubbles in contact is in the range of 100 to 600 μm.
On the other hand, the pre-expanded particles of Comparative Example 2 have a structure in which the average film thickness of the outermost layer is as thin as about 4.0 μm and the air bubbles in contact with the outermost layer are small (average cell diameter 84 μm). .
［試験２］
予備発泡粒子の嵩密度の違いにおける、発泡成形体の評価試験の結果を表３に示す。
[Test 2]
Table 3 shows the results of the evaluation test of the foamed molded product in the difference in the bulk density of the pre-expanded particles.
表３に記した通り、密度０．０２４〜０．０５０ｇ／ｃｍ３の範囲とした実施例４〜６は、黒色度及び加熱寸法変化率について良好な発泡成形体が得られた。
一方、密度０．０１９ｇ／ｃｍ３（発泡倍数５２．６倍）とした比較例３は、良好な発泡成形体が得られなかった。
さらに、本発明の所定の範囲（嵩発泡倍数２０〜４５倍）より小さい発泡倍数では、自動車内装材用途（例えば、ツールボックス、ティビアパッド）において、コスト面で受け入れられない。
As described in Table 3, in Examples 4 to 6 having a density in the range of 0.024 to 0.050 g / cm 3 , good foamed molded articles were obtained with respect to blackness and heating dimensional change rate.
On the other hand, in Comparative Example 3 having a density of 0.019 g / cm 3 (foaming factor: 52.6 times), a good foamed molded article could not be obtained.
Furthermore, a foaming factor smaller than the predetermined range (bulk foaming factor 20 to 45 times) of the present invention is not acceptable in terms of cost in automotive interior material applications (for example, tool boxes and tibia pads).
［試験３］
カーボンとポリポリプロピレン系樹脂（ＰＰ）との合計量１００質量部に対するポリスチレン系樹脂（ＰＳ）の量の違いにおける、発泡成形体の評価試験の結果を表４に示す。
[Test 3]
Table 4 shows the results of the evaluation test of the foam molded article in the difference in the amount of polystyrene resin (PS) with respect to 100 parts by mass of the total amount of carbon and polypolypropylene resin (PP).
表４に記した通り、ＰＰ樹脂／ＰＳ樹脂の割合が本発明の範囲内である実施例２，７及び８は、黒色度、加熱寸法変化率及び耐薬品性について良好な発泡成形体が得られた。
一方、ＰＰ樹脂／ＰＳ樹脂の割合が本発明の範囲外である比較例４は、黒色度、加熱寸法変化率及び耐薬品性の良好な発泡成形体が得られなかった。
As described in Table 4, Examples 2, 7 and 8 in which the ratio of PP resin / PS resin is within the scope of the present invention provide a foam molded article having good blackness, heating dimensional change rate and chemical resistance. It was.
On the other hand, in Comparative Example 4 in which the ratio of PP resin / PS resin was outside the range of the present invention, a foamed molded article having good blackness, heating dimensional change rate, and chemical resistance could not be obtained.
［試験４］
予備発泡粒子に対するカーボンの含有率の違いにおける、発泡成形体の評価試験結果を表５に示す。
[Test 4]
Table 5 shows the evaluation test results of the foamed molded product in the difference in the carbon content relative to the pre-expanded particles.
表５に記した通り、本発明に係る実施例２，９，１０は黒色度、加熱寸法変化率及び燃焼速度（遅燃性）について良好な発泡成形体が得られた。また、実施例２では、カーボン配合量１．６質量％と低い配合量で良好な黒色度が得られた。
一方、予備発泡粒子のカーボン配合量が本発明の範囲外である比較例５は、燃焼速度が８０ｍｍ／ｍｉｎより大きくなり遅燃性の良好な発泡成形体が得られなかった。
As shown in Table 5, in Examples 2, 9, and 10 according to the present invention, good foamed molded articles were obtained with respect to blackness, heating dimensional change rate, and burning rate (slow flammability). In Example 2, good blackness was obtained with a carbon content as low as 1.6 mass%.
On the other hand, in Comparative Example 5 in which the amount of carbon contained in the pre-expanded particles was outside the range of the present invention, the combustion rate was larger than 80 mm / min, and a foamed molded article having good slow-flammability was not obtained.
本発明の予備発泡粒子は、型内発泡成形して耐熱性及び黒色度に優れた発泡成形体を製造することができる。この発泡成形体は、自動車内装材（ツールボックス）、車輛用バンパーの芯材、ドア内装緩衝材などの車輛用緩衝材、電子部品、各種工業資材、食品などの搬送容器などの各種用途に用いることができる。 The pre-expanded particles of the present invention can be produced by in-mold foam molding to produce a foam molded article having excellent heat resistance and blackness. This foamed molded product is used in various applications such as automobile interior materials (tool boxes), vehicle bumper core materials, vehicle interior cushioning materials such as door interior cushioning materials, electronic parts, various industrial materials, and food containers. be able to.
Claims (14)
得られた分散液を前記スチレン系単量体が実質的に重合しない温度に加熱して前記スチレン系単量体を前記カーボン含有ポリプロピレン系樹脂粒子に含浸させる工程と、
前記カーボン含有ポリプロピレン系樹脂粒子中のポリプロピレン系樹脂の融点をＴ℃としたとき、（Ｔ−１０）℃〜（Ｔ＋２０）℃の温度で、前記スチレン系単量体の第１の重合を行う工程と、
前記第１の重合工程に続いて、スチレン系単量体と、重合開始剤とを加え、かつ、（Ｔ−２５）℃〜（Ｔ＋１０）℃の温度とすることにより、前記カーボン含有ポリプロピレン系樹脂粒子への前記スチレン系単量体の含浸および第２の重合を行ってカーボン含有改質ポリスチレン系樹脂粒子を得る工程と、
次いで、得られたカーボン含有改質ポリスチレン系樹脂粒子に発泡剤を含浸させて発泡性カーボン含有改質ポリスチレン系樹脂粒子を得る工程と、
次いで、得られた発泡性カーボン含有改質ポリスチレン系樹脂粒子を、ゲージ圧力０．００５〜０．０９ＭＰａの水蒸気を導入して加熱することによって予備発泡させて請求項１〜８のいずれか１項に記載のカーボン含有改質ポリスチレン系樹脂発泡粒子を得ることを特徴とするカーボン含有改質ポリスチレン系樹脂発泡粒子の製造方法。 A step of dispersing 100 parts by mass of carbon-containing polypropylene resin particles, 100 parts by mass or more and less than 400 parts by mass of a styrene monomer, and a polymerization initiator in an aqueous suspension containing a dispersant;
Heating the obtained dispersion to a temperature at which the styrenic monomer is not substantially polymerized to impregnate the carbon-containing polypropylene resin particles with the styrenic monomer;
The step of performing the first polymerization of the styrene monomer at a temperature of (T-10) ° C. to (T + 20) ° C., where T ° C. is the melting point of the polypropylene resin in the carbon-containing polypropylene resin particles. When,
Subsequent to the first polymerization step, a styrene monomer and a polymerization initiator are added, and the temperature is set to (T-25) ° C. to (T + 10) ° C. Performing impregnation of the styrenic monomer into particles and second polymerization to obtain carbon-containing modified polystyrene resin particles;
Next, a step of impregnating the obtained carbon-containing modified polystyrene resin particles with a foaming agent to obtain expandable carbon-containing modified polystyrene resin particles;
Next, the obtained expandable carbon-containing modified polystyrene resin particles are pre-expanded by introducing water vapor with a gauge pressure of 0.005 to 0.09 MPa and heating, to thereby expand any one of claims 1-8. A method for producing a carbon-containing modified polystyrene resin expanded particle, comprising obtaining the carbon-containing modified polystyrene resin expanded particle described in 1.
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| US7901602B2 (en) * | 2003-04-04 | 2011-03-08 | Sekisui Plastics Co., Ltd. | Expandable styrene-modified olefin resin particle, pre-expanded particle, and process for producing molded foam |
| JP4732822B2 (en) * | 2004-09-15 | 2011-07-27 | 積水化成品工業株式会社 | Black styrene-modified polyethylene resin particles and expandable resin particles thereof, methods for producing them, pre-expanded particles, and expanded molded article |
| CN101636423B (en) * | 2007-03-27 | 2013-03-27 | 积水化成品工业株式会社 | Particle of carbon-containing modified polystyrene resin, expandable particle of carbon-containing modified polystyrene resin, expanded particle of carbon-containing modified polystyrene resin, molded |
| JP5138254B2 (en) * | 2007-03-27 | 2013-02-06 | 積水化成品工業株式会社 | Modified polystyrene resin particles containing self-extinguishing carbon, Modified polystyrene resin particles containing foam, self-extinguishing carbon, Modified polystyrene resin foam particles containing self-extinguishing carbon, Modified polystyrene resin foam containing self-extinguishing carbon Molded body and method for producing the same |
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| CN109906242A (en) * | 2016-11-11 | 2019-06-18 | 株式会社Jsp | Expanded particle and expanded particle formed body |
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