JPH0739500B2 - Pre-expanded polypropylene resin particles - Google Patents
Pre-expanded polypropylene resin particlesInfo
- Publication number
- JPH0739500B2 JPH0739500B2 JP9395487A JP9395487A JPH0739500B2 JP H0739500 B2 JPH0739500 B2 JP H0739500B2 JP 9395487 A JP9395487 A JP 9395487A JP 9395487 A JP9395487 A JP 9395487A JP H0739500 B2 JPH0739500 B2 JP H0739500B2
- Authority
- JP
- Japan
- Prior art keywords
- peak
- expanded particles
- particles
- resin
- high temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は型内発泡成型用に用いられるポリプロピレン系
樹脂予備発泡粒子に関し、更に詳しくは予備発泡粒子を
成型用型に充填して加熱発泡せしめて成型体とするに際
し、型に充填する予備発泡粒子の内圧が大気圧と略等し
い場合でも、粒子に内圧付与の前処理を行わずとも良好
に成型することができるポリプロピレン系樹脂予備発泡
粒子に関する。TECHNICAL FIELD The present invention relates to polypropylene resin pre-expanded particles used for in-mold foam molding, and more specifically, the pre-expanded particles are filled in a molding die for heat expansion. A polypropylene-based resin pre-expanded particle which can be favorably molded without performing a pretreatment of applying an internal pressure to the particle even when the internal pressure of the pre-expanded particle to be filled in the mold is approximately equal to the atmospheric pressure when forming a molded article .
ポリオレフィン系樹脂の予備発泡粒子を型内に充填して
加熱発泡せしめ、型通りの成型体を得る方法は広く知ら
れている（例えば特開昭47−34458号公報、特開昭49−8
5158号公報、特開昭49−128065号公報等）が、ポリオレ
フィン系樹脂はポリスチレン系樹脂に比べて気体の透過
性や溶融時の粘弾性、流動特性等が著しく異なるため、
気泡内の発泡用ガスが予備発泡粒子製造後すぐに粒子内
より逃散して発泡能の低下をきたし、得られる成型体に
収縮を生じたり、粒子間の融着が不充分となったりする
問題があり、これを防止するために上記従来の方法では
成型に先だって予備発泡粒子に発泡剤ガスや空気等の無
機ガスを追添して内圧を付与する方法を採用している。
しかしながら予備発泡粒子に発泡用ガスや無機ガスを追
添することは、設備上及び経費上で多大な出費がかさ
み、成型体の製造コストが高くつくという問題があっ
た。しかもポリオレフィン系樹脂予備発泡粒子は、無機
ガス等を追添して内圧を高めることによって発泡能を付
与しても、粒子内ガスが抜け易いために発泡能を長時間
維持することが困難であり、これら従来の方法において
優れた成型体を得るには内圧付与後、予備発泡粒子を短
時間で消費しなければならず、成型業者が予備発泡粒子
製造業者から予備発泡粒子の供給を受けるだけで、容易
に成型体を製造することができるというものではなかっ
た。A method for filling a pre-expanded particle of a polyolefin resin in a mold and heat-foaming it to obtain a molded product as a mold is widely known (for example, JP-A-47-34458 and JP-A-49-8).
5158, JP-A-49-128065, etc.), the polyolefin resin is significantly different from polystyrene resin in gas permeability, viscoelasticity during melting, flow characteristics, etc.,
The problem that the foaming gas in the bubbles escapes from the inside of the particles immediately after the production of pre-expanded particles and causes a decrease in the foaming ability, resulting in shrinkage of the molded body or insufficient fusion between particles. In order to prevent this, the above-mentioned conventional method employs a method in which an inorganic gas such as a blowing agent gas or air is added to the pre-expanded particles to give an internal pressure prior to molding.
However, adding a foaming gas or an inorganic gas to the pre-expanded particles involves a large amount of expense in terms of equipment and cost, and there is a problem that the manufacturing cost of the molded body is high. Moreover, the polyolefin resin pre-expanded particles are difficult to maintain the foaming ability for a long time because the gas inside the particles easily escapes even when the foaming ability is imparted by adding an inorganic gas or the like to increase the internal pressure. In order to obtain an excellent molded product in these conventional methods, the pre-expanded particles have to be consumed in a short time after the internal pressure is applied, and the molder only needs to be supplied with the pre-expanded particles from the pre-expanded particle manufacturer. However, it has not been that a molded body can be easily manufactured.
一方、特公昭55−7816号公報にはポリエチレン系樹脂予
備発泡粒子に無機ガス等を追添して内圧を付与する前処
理を行わずに成型し、次いで樹脂の軟化温度以下〜常温
まで冷却した後、樹脂の軟化温度以下〜軟化温度から40
℃低い温度に昇温し、その後徐冷し成型体を得る方法が
開示されているが、ポリエチレン系樹脂とポリプロピレ
ン系樹脂とでは樹脂物性が異なり、ポリエチレン系樹脂
予備発泡粒子の技術を単純にポリプロピレン系予備発泡
粒子に適用しても、ポリエチレン系樹脂予備発泡粒子の
場合と同様な効果を得ることはできなかった。On the other hand, Japanese Patent Publication No. 55-7816 discloses that polyethylene-based resin pre-expanded particles are molded without pretreatment of adding an internal pressure by adding an inorganic gas or the like, and then cooled to a temperature below the softening temperature of the resin to room temperature. After the softening temperature of the resin ~ 40 from the softening temperature
A method of obtaining a molded product by raising the temperature to a low temperature of ℃ and then gradually cooling is disclosed. However, the resin physical properties are different between polyethylene resin and polypropylene resin, and the technique of polyethylene resin pre-expanded particles is simply polypropylene. Even when applied to the system pre-expanded particles, the same effect as that of the polyethylene resin pre-expanded particles could not be obtained.
本発明者らは上記の点に鑑み鋭意研究した結果、予備発
泡粒子の示差走査熱量測定によって得られるDSC曲線に
ポリプロピレン系樹脂に固有の固有ピークと、該固有ピ
ークの温度より高温側の高温ピークとが現れる結晶構造
を有し、嵩密度が0.04g/cm3以上においては高温ピーク
の融解エネルギーが８〜12J/gであり、嵩密度が0.04g/c
m3未満においては高温ピークの融解エネルギーが8J以上
であるポリプロピレン系樹脂予備発泡粒子が成型のため
の内圧付与の前処理を行わずとも成型できることを見出
し、先に先願を行った（特願昭60−268869号((特開昭62
−128709))）。しかしながらこの発明では嵩密度0.04g/
cm3以上の粒子では、高温ピークの融解エネルギーが８
〜12J/gのものしか内圧付与の前処理を行わずに成型す
ることができず、この点を改良すべき本発明者らは鋭意
研究した結果、気泡径が3mm以下であると、本発明者ら
の先願発明において内圧付与の前処理を行わずに成型す
ることが困難であった嵩密度0.04g/cm3以上であって高
温ピークの融解エネルギーが12J/gを超える予備発泡粒
子でも、12〜20J/gの融解エネルギーを有していれば内
圧付与の前処理を行わずとも成型ができ、更に融解エネ
ルギーが上記特願昭60−268869号の範囲にある場合に
は、気泡径が3mm以下であると成型蒸気圧を低くしても
良好な成型体を得ることができ、成型サイクルの短縮
（冷却時間の短縮）を図れることを見出したが、嵩密度
が0.04g/cm3以上の粒子の場合、気泡径が3mmを超えると
融解エネルギーが12J/gを超える粒子では内圧付与の前
処理を行わずに成型することが困難となるという問題も
あった。そこで本発明者らは更に鋭意研究した結果、粒
子の重量が3mg以上であると気泡径が3mmを超えても嵩密
度0.04g/cm3以上で高温ピークの融解エネルギーが12〜2
0J/gのものも内圧付与の前処理なしに成型することがで
きるとともに、成型蒸気圧を更に低くしても良好な成型
体を得ることができ、なお一層成型サイクルの短縮及び
コスト低減化を図れることを見出し本発明を完成するに
至った。As a result of intensive studies conducted by the present inventors in view of the above points, a unique peak specific to polypropylene resin in a DSC curve obtained by differential scanning calorimetry of pre-expanded particles, and a high temperature peak on a higher temperature side than the temperature of the unique peak. When the bulk density is 0.04 g / cm 3 or more, the melting energy of the high temperature peak is 8 to 12 J / g, and the bulk density is 0.04 g / c.
We found that polypropylene-based resin pre-expanded particles whose melting energy at the high temperature peak is 8 J or more at m 3 or less can be molded without performing pretreatment of applying internal pressure for molding, and first filed a patent application (Patent application Sho 60-268869 ((JP 62
−128709))). However, in this invention, the bulk density is 0.04 g /
For particles of cm 3 and above, the melting energy of the high temperature peak is 8
Only those having ~ 12 J / g can be molded without pretreatment of applying internal pressure, and the inventors of the present invention who should improve this point have diligently studied and found that the bubble diameter is 3 mm or less. Even in pre-expanded particles having a high-temperature peak melting energy of more than 12 J / g and having a bulk density of 0.04 g / cm 3 or more, which was difficult to mold without performing pretreatment of applying internal pressure in the inventors' prior invention. , As long as it has a melting energy of 12 to 20 J / g, it can be molded without pretreatment of applying internal pressure, and if the melting energy is in the range of Japanese Patent Application No. 60-268869, the cell diameter It was found that when the value is 3 mm or less, a good molded product can be obtained even if the molding vapor pressure is lowered, and the molding cycle can be shortened (cooling time shortened), but the bulk density is 0.04 g / cm 3 In the case of the above particles, if the bubble diameter exceeds 3 mm, the melting energy exceeds 12 J / g. It was also of pre-treating the problem that it is difficult to mold without. Therefore, as a result of further intensive studies by the present inventors, when the weight of the particles was 3 mg or more, the melting energy of the high temperature peak was 12 to 2 at a bulk density of 0.04 g / cm 3 or more even if the bubble diameter exceeded 3 mm.
It is possible to mold even 0 J / g without pretreatment of applying internal pressure, and it is possible to obtain a good molded body even if the molding vapor pressure is further lowered, further shortening the molding cycle and cost reduction. The inventors have found that it can be achieved and completed the present invention.
即ち本発明はポリプロピレン系樹脂を基材樹脂とする予
備発泡粒子であって、示差走査熱量測定によって得られ
るDSC曲線（但し、予備発泡粒子１〜3mgを示差走査熱量
計によって10℃／分の昇温速度で220℃まで昇温して測
定したときに得られるDSC曲線）に、ポリプロピレン系
樹脂固有の固有ピークと、該固有ピークの温度より高温
側の高温ピークとが現れる結晶構造を有し、かつ重量が
3mg以上であるとともに、嵩密度が0.04g/cm3以上におい
ては前記高温ピークの融解エネルギーが８〜20J/gであ
り、嵩密度が0.04g/cm3未満においては高温ピークの融
解エネルギーが8J/g以上であることを特徴とする成型の
ための内圧付与の前処理を要しないポリプロピレン系樹
脂予備発泡粒子を要しとするものである。That is, the present invention is a pre-expanded particles using a polypropylene resin as a base resin, DSC curve obtained by differential scanning calorimetry (however, pre-expanded particles 1-3 mg 10 ° C. / min increase by differential scanning calorimeter. The DSC curve obtained when the temperature is increased to 220 ° C. at the time of measurement, and has a crystal structure in which a characteristic peak peculiar to a polypropylene resin and a high temperature peak on the higher temperature side than the temperature of the characteristic peak appear. And the weight
The melting energy of the high temperature peak is 8 to 20 J / g when the bulk density is 0.04 g / cm 3 or more and the melting energy of the high temperature peak is 8 J when the bulk density is less than 0.04 g / cm 3. A polypropylene resin pre-expanded particle which does not require a pretreatment for applying an internal pressure for molding, which is characterized by having a content of at least 1 g / g.
本発明において用いるポリプロピレン系樹脂としてはエ
チレン−プロピレンランダム共重合体、エチレン−プロ
ピレンブロック共重合体、プロピレン単独共重合体、プ
ロピレン−ブテンランダム共重合体等が挙げられ、共重
合体の場合、プロピレン成分が50重量％以上のものが好
ましい。上記樹脂のなかでもエチレン−プロピレンラン
ダム共重合体が好ましく、特にエチレン成分１〜10重量
％のエチレン−プロピレンランダム共重合体が好まし
い。Examples of the polypropylene resin used in the present invention include ethylene-propylene random copolymers, ethylene-propylene block copolymers, propylene homocopolymers, propylene-butene random copolymers, and the like. It is preferable that the components are 50% by weight or more. Among the above resins, an ethylene-propylene random copolymer is preferable, and an ethylene-propylene random copolymer having an ethylene component of 1 to 10% by weight is particularly preferable.
本発明においてポリプロピレン系樹脂予備発泡粒子の示
差走査熱量測定によって得られるDSC曲線とは、予備発
泡粒子１〜3mgを示差走査熱量計によって10℃／分の昇
温速度で220℃まで昇温して測定した時に得られるDSC曲
線であり、DSC曲線における固有ピークと高温ピークと
は例えば試料を室温から220℃まで10℃／分で昇温測定
した時に得られるDSC曲線（第１回目のDSC曲線）と、22
0℃まで昇温後、10℃／分で40℃付近まで降温し、再度1
0℃／分で220℃まで昇温測定して得られたDSC曲線（第
２回目のDSC曲線）とから求めることができる。The DSC curve obtained by the differential scanning calorimetry of polypropylene resin pre-expanded particles in the present invention means that the pre-expanded particles 1 to 3 mg are heated to 220 ° C. at a heating rate of 10 ° C./min by a differential scanning calorimeter. It is a DSC curve obtained at the time of measurement, and the specific peak and the high temperature peak in the DSC curve are, for example, the DSC curve obtained at the time of measuring the temperature of the sample from room temperature to 220 ° C at 10 ° C / min (the first DSC curve). And 22
After raising the temperature to 0 ° C, lower the temperature at 10 ° C / min to around 40 ° C.
It can be determined from the DSC curve (second DSC curve) obtained by measuring the temperature at 0 ° C./minute up to 220 ° C.
即ち固有ピークとは予備発泡粒子を構成するポリプロピ
レン系樹脂に固有の吸熱ピークであり、樹脂の所謂融解
時の吸熱によるものと考えられる。固有ピークは第１回
目のDSC曲線にも第２回目のDSC曲線にも現れ、ピークの
頂点の温度は第１回目と第２回目で多少異なる場合があ
るが、その差は５℃未満、通常は２℃未満である。一
方、高温ピークとは第１回目のDSC曲線で上記固有ピー
クより高温側に現れる吸熱ピークであり、この高温ピー
クは固有ピークとして現れる構造とは異なる結晶構造の
存在によるものと考えられ、高温ピークは、第１回目の
DSC曲線と同一条件で昇温測定を行った第２回目のDSC曲
線には現れない。従って高温ピークは基材樹脂自体の結
晶構造等に起因するものではなく、予備発泡粒子として
の形態における結晶構造等に起因するものと考えられ
る。第１回目のDSC曲線に現れる高温ピークの頂点の温
度と、第２回目のDSC曲線に現れる固有ピークの頂点の
温度との差は大きいことが好ましく、両者の差は５℃以
上、特に10℃以上であることが好ましい。第１回目のDS
C曲線にこの高温ピークの現れない結晶構造のポリプロ
ピレン系樹脂予備発泡粒子は成型性が悪く、良好な成型
体を得ることが困難となる。That is, the unique peak is an endothermic peak specific to the polypropylene resin that constitutes the pre-expanded particles, and is considered to be due to the so-called endotherm when the resin is melted. The peculiar peak appears in both the first DSC curve and the second DSC curve, and the temperature at the peak apex may be slightly different between the first and second times, but the difference is less than 5 ° C, usually. Is less than 2 ° C. On the other hand, the high temperature peak is an endothermic peak that appears on the higher temperature side than the above-mentioned specific peak in the first DSC curve, and it is considered that this high temperature peak is due to the existence of a crystal structure different from the structure that appears as the specific peak. Is the first
It does not appear in the second DSC curve that was measured under the same conditions as the DSC curve. Therefore, it is considered that the high temperature peak is not caused by the crystal structure of the base resin itself, but by the crystal structure in the form of pre-expanded particles. It is preferable that the difference between the temperature at the apex of the high temperature peak appearing on the first DSC curve and the temperature at the apex of the unique peak appearing on the second DSC curve is large. The difference between the two is 5 ° C or more, especially 10 ° C. The above is preferable. 1st DS
The polypropylene resin pre-expanded particles having a crystal structure in which the high temperature peak does not appear on the C curve have poor moldability, and it is difficult to obtain a good molded product.
本発明予備発泡粒子は内圧付与の前処理を行わずとも良
好な成型体を得ることができるという目的を達するため
には予備発泡粒子の嵩密度と、上記高温ピークの融解エ
ネルギー（高温ピークの面積）とが特定の値を有し、更
に特定以上の重量を有することが必要である。本発明の
予備発泡粒子における上記高温ピークの融解エネルギー
は、嵩密度が0.04g/cm3以上の粒子では８〜20J/gである
ことが必要であり、嵩密度が0.04g/cm3未満の予備発泡
粒子では8J/g以上であることが必要である。また本発明
の予備発泡粒子は重量3mg以上であることが必要であ
り、特に３〜6mgであることが好ましい。粒子重量が3mg
未満の場合、粒子の気泡径が3mmを超えるものである
と、嵩密度0.04g/cm3以上の粒子では高温ピークの融解
エネルギーが８〜12J/gのものでないと、内圧付与の前
処理を行わずに良好な成型体を得ることができず、12J/
gを超えるものは内圧付与の前処理を行わなければ事実
上成型を行うことはがきない。The pre-expanded particles of the present invention have the bulk density of the pre-expanded particles and the melting energy of the above-mentioned high temperature peak (area of the high temperature peak) in order to achieve the object that a good molded product can be obtained without performing pretreatment of applying internal pressure. ) And have specific values, and moreover have a specific weight or more. The melting energy of the above-mentioned high temperature peak in the pre-expanded particles of the present invention needs to be 8 to 20 J / g for particles having a bulk density of 0.04 g / cm 3 or more, and a bulk density of less than 0.04 g / cm 3 . For pre-expanded particles, it is necessary to be 8 J / g or more. Further, the pre-expanded particles of the present invention need to have a weight of 3 mg or more, and particularly preferably 3 to 6 mg. Particle weight is 3 mg
When the bubble diameter of the particles is more than 3 mm, the high temperature peak melting energy of particles with a bulk density of 0.04 g / cm 3 or more must be 8 to 12 J / g. 12J /
If it exceeds g, it cannot be practically molded without the pretreatment of applying internal pressure.
上記高温ピークの融解エネルギーが8J/g未満の場合、こ
の予備発泡粒子を用いて成型した成型体を型より取出し
た時の成型体の収縮が大きいという問題がある。その理
由は高温ピークの融解エネルギーが小さい予備発泡粒子
ではそれを構成する膜（セル）の強度が小さいためと考
えられる。また嵩密度が0.04g/cm3以上の粒子では高温
ピークの融解エネルギーが20J/gを超えると二次発泡性
が悪く、ボイドの少ない成型体を得ることができない。
本発明の予備発泡粒子は重量が3mg以上であることによ
って、嵩密度が0.04g/cm3以上で、高温ピークの融解エ
ネルギーが12J/gを超える粒子において、該粒子の気泡
径が3mmを超える場合でも内圧付与の前処理を行わずに
成型が可能であり、嵩密度が0.04g/cm3以上の粒子は融
解エネルギーが８〜20J/gのものまで内圧付与の前処理
を行わずに良好な成型体を得ることができる。これは粒
子の重量が3mg以上であると、同一嵩密度かつ同一高温
ピークの融解エネルギーのもので粒子重量が3mg未満の
ものに比べ、金型内に発泡粒子を充填し加熱発泡させる
際に発泡粒子内のガスが逃げにくく、この結果二次発泡
し易くなるためと考えられる。本発明において上記粒子
の重量とは予備発泡粒子をランダムに10個抜取ってその
重量を測定した結果を平均して求めた値である。When the melting energy of the above-mentioned high temperature peak is less than 8 J / g, there is a problem that the molded product formed by using the pre-expanded particles has a large shrinkage when taken out from the mold. It is considered that the reason is that the pre-expanded particles having a low melting energy of the high temperature peak have a low strength of the film (cell) constituting them. Further, in the case of particles having a bulk density of 0.04 g / cm 3 or more, if the melting energy of the high temperature peak exceeds 20 J / g, the secondary foaming property is poor and a molded product with few voids cannot be obtained.
The pre-expanded particles of the present invention have a weight of 3 mg or more, so that the bulk density is 0.04 g / cm 3 or more, and the melting energy of the high temperature peak exceeds 12 J / g, and the bubble diameter of the particles exceeds 3 mm. Even if it is possible to mold without performing pretreatment of applying internal pressure, particles with a bulk density of 0.04 g / cm 3 or more have good melting energy up to 8-20 J / g without pretreatment of applying internal pressure. It is possible to obtain such a molded body. This is because when the weight of the particles is 3 mg or more, foaming occurs when the foamed particles are filled in the mold and heated and foamed, as compared with those with the same bulk density and the same high temperature peak melting energy and particle weight of less than 3 mg. It is considered that the gas in the particles is hard to escape, and as a result, secondary foaming is likely to occur. In the present invention, the weight of the particles is a value obtained by averaging the results obtained by randomly extracting 10 pre-expanded particles and measuring the weight.
本発明の予備発泡粒子は必要に応じて気泡調整剤を配合
したポリプロピレン系樹脂粒子を密閉容器内で例えばジ
クロロジフロロメタン等の発泡剤及び必要により微粒状
の酸化アルミニウム等の分散剤とともに水等の分散媒に
分散させて撹拌下に加熱して発泡剤を樹脂粒子に含浸さ
せた後、樹脂粒子と分散媒とを容器内より低圧の雰囲気
下に放出して樹脂粒子を発泡せしめる方法等により得ら
れるが、このとき樹脂粒子100重量部当たり発泡剤５〜3
0重量部とし、容器内で融解終了温度:TE以上に昇温する
ことなく、樹脂の融点:Tm付近で一旦５〜20分程度の時
間保持した後、発泡温度（通常Tm−５〜Tm＋10℃）に昇
温して容器の一端を開放し、樹脂粒子と水とを放出する
方法を採用することによって高温ピークの融解エネルギ
ーが特定の値を有する予備発泡粒子が得られ、Tm付近で
一旦保持することにより高温ピークの融解エネルギーの
値を調整することができる。しかしながら一旦TE以上に
昇温した場合は高温ピークの存在しない予備発泡粒子し
か得られない。The pre-expanded particles of the present invention include polypropylene resin particles mixed with a cell adjuster as necessary in a closed container together with a foaming agent such as dichlorodifluoromethane and optionally a dispersant such as finely divided aluminum oxide and water. After the resin particles are dispersed in the dispersion medium and heated under stirring to impregnate the resin particles with the foaming agent, the resin particles and the dispersion medium are discharged from the container under a low pressure atmosphere to foam the resin particles. A foaming agent of 5 to 3 is obtained per 100 parts by weight of resin particles.
The melting point of the resin is 0 part by weight, and the melting point of the resin is not raised to T E or more, and the melting point of the resin is kept at around Tm for about 5 to 20 minutes, and then the foaming temperature (usually Tm-5 to Tm + 10 (° C) to open one end of the container and release the resin particles and water to obtain pre-expanded particles having a high temperature peak melting energy with a specific value. By holding the value, the melting energy value of the high temperature peak can be adjusted. However, once the temperature is raised above T E, only pre-expanded particles without a high temperature peak can be obtained.
本発明において上記した気泡調整剤としてはタルク、シ
リカ、炭酸塩、酸化亜鉛、ステアリン酸塩等が挙げら
れ、これらの配合量は通常樹脂100重量部に対して0.01
〜１重量部であり、配合量を変えることにより得られる
予備発泡粒子の気泡径を任意に変えることができる。ま
た気泡調整剤以外で気泡径を変化させる因子としては、
発泡温度、加熱保持時間が挙げられ、これらの設定によ
っても容易に気泡径を変化させることができる。Examples of the above-mentioned foam control agent in the present invention include talc, silica, carbonates, zinc oxide, stearates and the like, and the compounding amount thereof is usually 0.01 with respect to 100 parts by weight of the resin.
˜1 part by weight, and the bubble diameter of the pre-expanded particles obtained by changing the blending amount can be arbitrarily changed. In addition, as factors that change the bubble diameter other than the bubble regulator,
The foaming temperature and the heating and holding time are mentioned, and the bubble diameter can be easily changed by these settings.
本発明の予備発泡粒子は型内に充填して加熱発泡せしめ
て型通りの成型体とする、所謂型内発泡用原料として用
いられるが、本発明予備発泡粒子はたとえ粒子内圧が大
気圧と略等しい状態であったとしても、成型に先だって
内圧付与の前処理を行わずとも良好な成型体を得ること
ができる。The pre-expanded particles of the present invention are used as a so-called in-mold foaming raw material which is filled in a mold and heat-foamed to obtain a molded product as a mold, but the pre-expanded particles of the present invention have a particle internal pressure substantially equal to atmospheric pressure. Even if they are in the same state, a good molded product can be obtained without performing a pretreatment of applying internal pressure prior to molding.
以下実施例を挙げて本発明を更に詳細に説明する。 Hereinafter, the present invention will be described in more detail with reference to examples.
実施例１〜６、比較例１〜７ 密閉容器にタルクを含有する（但し実施例５、６、比較
例７は含有せず）エチレン−プロピレンランダム共重合
体粒子（エチレン成分2.8重量％、Tm＝142℃、TE＝152
℃）100重量部、水300重量部、微粒状の酸化アルミニウ
ム0.3重量部及び第１表に示す量のジクロロジフロロメ
タンを配合し、撹拌しながら第１表に示す温度まで加熱
して同表に示す時間保持し、次いで第１表に示す発泡温
度まで昇温して同表に示す時間保持した後、容器内圧を
窒素ガスにて40kg/cm2・Ｇに保ちながら容器の一端を開
放し、樹脂粒子と水とを同時に大気圧下に放出して予備
発泡粒子を得た。樹脂粒子が容器内にある間の容器内最
高温度及び、得られた各予備発泡の性状を第２表に示
す。尚、予備発泡粒子の高温ピークの融解エネルギーは
以下の式より求めた。Examples 1 to 6 and Comparative Examples 1 to 7 Ethylene-propylene random copolymer particles containing talc in a closed container (however, not containing Examples 5, 6 and Comparative Example 7) (ethylene component: 2.8% by weight, Tm) = 142 ° C, T E = 152
100 parts by weight, 300 parts by weight of water, 0.3 parts by weight of finely divided aluminum oxide and the amount of dichlorodifluoromethane shown in Table 1 are mixed and heated to the temperature shown in Table 1 with stirring. After holding for the time shown in Table 1, then raising the temperature to the foaming temperature shown in Table 1 and holding it for the time shown in the same table, open one end of the container while keeping the internal pressure of the container at 40 kg / cm 2 · G with nitrogen gas. , Resin particles and water were simultaneously released under atmospheric pressure to obtain pre-expanded particles. Table 2 shows the maximum temperature inside the container while the resin particles were inside the container, and the properties of each pre-foaming obtained. The melting energy of the high temperature peak of the pre-expanded particles was calculated by the following formula.
融解エネルギー（J/g） ＝〔高温ピークのチャート上の面積（cm2）〕 ×〔チャート1cm2当たりの熱量（J/cm2）〕 ÷〔測定サンプル重量（ｇ）〕 高温ピークの面積は第１図に示すように高温ピークｂの
融解終了温度T1より低温側に向かって水平に引いた直線
と、第２回目のDSC曲線（点線）の固有ピークa2におけ
る融解終了温度T2を通って垂直に引いた直線と、第１回
目のDSC曲線（実線）とによって囲まれた部分である。Melting energy (J / g) = [area of high temperature peak on chart (cm 2 )] x [calorie per 1 cm 2 of chart (J / cm 2 )] ÷ [measured sample weight (g)] Area of high temperature peak is As shown in FIG. 1, a straight line drawn horizontally from the melting end temperature T 1 of the high temperature peak b toward the lower temperature side and the melting end temperature T 2 at the unique peak a 2 of the second DSC curve (dotted line) are shown. It is the part surrounded by a straight line drawn vertically through it and the first DSC curve (solid line).
尚、図中a1は第１回目のDSC曲線における固有ピークを
示す。In the figure, a 1 indicates a unique peak in the first DSC curve.
次に得られた各予備発泡粒子を室温にて大気圧下で24時
間放置して熟成後、それぞれ300mm×300mm×60mmの金型
に充填し、金型内を560mm Hgに減圧した後、蒸気で加熱
して成型した。冷却後、成型体を型から取出して60℃で
24時間養生し、次いで室温で24時間放置した後に成型体
の性状を評価した。成型は実施例１〜６、比較例１、６
では第２表に示す最低成型蒸気圧で行い、比較例２〜
５、７では成型装置にかけ得る蒸気圧の上限に近い4.0k
g/cm2（Ｇ）で行った。また成型後の成型体を冷却する
に必要な冷却時間を測定した。これらの結果を第２表に
あわせて示す。Next, each pre-expanded particle obtained is left to stand at room temperature under atmospheric pressure for 24 hours, aged, and then filled in a mold of 300 mm × 300 mm × 60 mm, and the pressure inside the mold is reduced to 560 mm Hg, and then steamed. It was heated in and molded. After cooling, remove the molded body from the mold at 60 ° C
After being cured for 24 hours and then left at room temperature for 24 hours, the properties of the molded body were evaluated. Molding was performed in Examples 1 to 6 and Comparative Examples 1 and 6.
Then, the minimum forming vapor pressure shown in Table 2 was used, and Comparative Example 2
In 5 and 7, 4.0k is close to the upper limit of vapor pressure that can be applied to the molding equipment.
It was performed at g / cm 2 (G). Also, the cooling time required to cool the molded body after molding was measured. These results are also shown in Table 2.
※１二次発泡性は、成型体表面を観察し、 表面が平滑で融着良好 ……○ ボイドがやや有るが融着良好 ……△ ボイドが多い ……× として評価した。 * 1 The secondary foaming property was evaluated by observing the surface of the molded product and observing the surface being smooth and having good fusion ・ ・ ・ ○ Good fusion, although there are some voids ・ ・ ・ △ Many voids ・ ・ ・ ×
※２面方向収縮率は、成型直後の成型体を60℃で24時間
養生し、次いで室温で24時間放置した後の寸法を測定
し、 収縮率３％未満 ……○ 収縮率３〜５％ ……△ 収縮率５％を超える ……× として評価した。* 2 In-plane shrinkage is measured by aging the molded body immediately after molding at 60 ° C for 24 hours and then leaving it at room temperature for 24 hours, and then measuring the dimensions. Shrinkage is less than 3% …… ○ Shrinkage is 3 to 5% …… △ Shrinkage rate exceeded 5% ・ ・ ・ It was evaluated as ×.
※３厚さ方向収縮率は、成型直後の成型体を60℃で24時
間養生し、次いで室温で24時間放置した後の成型体中心
部の寸法を測定し、 収縮率３％未満 ……○ 収縮率３〜５％ ……△ 収縮率５％を超える ……× として評価した。* 3 The shrinkage in the thickness direction is less than 3% by measuring the size of the center of the molded body after curing the molded body immediately after molding at 60 ° C for 24 hours and then leaving it at room temperature for 24 hours. Shrinkage rate of 3 to 5% …… △ Shrinkage rate of more than 5% was evaluated as ×.
※４最低成型蒸気圧（kg/cm2（Ｇ））は二次発泡性、面
方向及び厚さ方向収縮率の評価の全てを○とするに必要
な成型時の最低蒸気圧を意味する。* 4 Minimum molding vapor pressure (kg / cm 2 (G)) means the minimum vapor pressure during molding required for all evaluations of secondary foamability, shrinkage in the surface and thickness directions to be ○.
※５冷却時間は、最低成型蒸気圧にて成型した後の水冷
時間である。* 5 Cooling time is the water cooling time after molding with the minimum molding vapor pressure.
以上説明したように本発明ポリプロピレン系樹脂予備発
泡粒子は、示差走査熱量測定によって得られるDSC曲線
に、ポリプロピレン系樹脂固有の固有ピークと、該固有
ピークの温度より高温側の高温ピークとが現れる結晶構
造を有し、かつ重量が3mg以上であるとともに、粒子の
嵩密度が0.04g/cm3以上においては前記高温ピークの融
解エネルギーが８〜20J/gであり、嵩密度が0.04g/cm3未
満においては高温ピークの融解エネルギーが8J/g以上で
ある構成を有することにより、この予備発泡粒子を成型
する場合、たとえ予備発泡粒子の粒子内圧が大気圧と略
等しいような状態であっても、内圧付与の前処理を行わ
ずとも優れた成型体を得ることができ、予備発泡粒子に
内圧を付与するための設備や内圧付与工程にかかる経費
を削減することができ、成型体の製造コストの大幅な低
廉化を果たすことができる。また予備発泡粒子の内圧付
与を行わないことによって、成型業者は予備発泡粒子製
造業者から提供され、在庫している予備発泡粒子を必要
なときにいつでも取出して直ちに成型することができる
から成型業者はきわめて効率のよい成型体製造を行うこ
とができる。更に本発明の予備発泡粒子は重量が3mg以
上であることによって、嵩密度が0.04g/cm3以上の粒子
の場合、粒子の気泡径が3mmを超えても高温ピークの融
解エネルギーが12J/gを超え、20J/gのものまで内圧付与
の前処理を行わずとも成型できるようになったととも
に、本発明者らの先願発明に比べて成型時の蒸気圧が低
くて済み、蒸気にかかるコストを少なくすることがで
き、更に冷却時間を短縮できるため成型体の製造コスト
低減化を図れる等の種々の効果を有するものである。As described above, the polypropylene resin pre-expanded particles of the present invention have a DSC curve obtained by differential scanning calorimetry, a characteristic peak specific to the polypropylene resin, and a high temperature peak on a higher temperature side than the temperature of the characteristic peak are crystals. It has a structure and a weight of 3 mg or more, and when the bulk density of the particles is 0.04 g / cm 3 or more, the melting energy of the high temperature peak is 8 to 20 J / g, and the bulk density is 0.04 g / cm 3. By having a constitution in which the melting energy of the high temperature peak is 8 J / g or more in the case of molding the pre-expanded particles, even if the internal pressure of the pre-expanded particles is substantially equal to the atmospheric pressure. It is possible to obtain an excellent molded product without performing pretreatment of applying internal pressure, and it is possible to reduce the cost required for the equipment for applying the internal pressure to the pre-expanded particles and the internal pressure applying process. It can play a significant cost reduction in manufacturing cost. Also, by not applying internal pressure to the pre-expanded particles, the molder is provided by the pre-expanded particle manufacturer, and the pre-expanded particles in stock can be taken out at any time and molded immediately, It is possible to manufacture a molded body with extremely high efficiency. Further, the pre-expanded particles of the present invention have a weight of 3 mg or more, so that when the bulk density is 0.04 g / cm 3 or more, the melting energy of the high temperature peak is 12 J / g even if the bubble diameter of the particles exceeds 3 mm. Over 20 J / g, it became possible to mold even without performing pretreatment of applying internal pressure, and the vapor pressure at the time of molding was lower than that of the inventors' prior invention, and the steam was applied. Since the cost can be reduced and the cooling time can be further shortened, various effects such as reduction of the manufacturing cost of the molded body can be achieved.
第１図は予備発泡粒子の示差走査熱量測定によって得ら
れるDSC曲線である。FIG. 1 is a DSC curve obtained by differential scanning calorimetry of pre-expanded particles.
Claims (2)
備発泡粒子であって、示差走査熱量測定によって得られ
るDSC曲線（但し、予備発泡粒子１〜3mgを示差走査熱量
計によって10℃／分の昇温速度で220℃まで昇温して測
定したときに得られるDSC曲線）に、ポリプロピレン系
樹脂固有の固有ピークと、該固有ピークの温度より高温
側の高温ピークとが現れる結晶構造を有し、かつ重量が
3mg以上であるとともに、嵩密度が0.04g/cm3以上におい
ては前記高温ピークの融解エネルギーが８〜20J/gであ
り、嵩密度が0.04g/cm3未満においては高温ピークの融
解エネルギーが8J/g以上であることを特徴とする成型の
ための内圧付与の前処理を要しないポリプロピレン系樹
脂予備発泡粒子。1. Pre-expanded particles using a polypropylene resin as a base resin, which is a DSC curve obtained by differential scanning calorimetry (however, 1 to 3 mg of pre-expanded particles is 10 ° C./min by a differential scanning calorimeter). The DSC curve obtained when the temperature is raised to 220 ° C. at the heating rate), and has a crystal structure in which a peculiar peak peculiar to polypropylene resin and a high-temperature peak on the higher temperature side than the temperature of the peculiar peak appear. , And the weight
The melting energy of the high temperature peak is 8 to 20 J / g when the bulk density is 0.04 g / cm 3 or more and the melting energy of the high temperature peak is 8 J when the bulk density is less than 0.04 g / cm 3. / g or more, polypropylene-based resin pre-expanded particles which do not require pretreatment for imparting internal pressure for molding.
レンランダム共重合体である特許請求の範囲第１項記載
のポリプロピレン系樹脂予備発泡粒子。2. The polypropylene resin pre-expanded particles according to claim 1, wherein the polypropylene resin is an ethylene-propylene random copolymer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9395487A JPH0739500B2 (en) | 1987-04-16 | 1987-04-16 | Pre-expanded polypropylene resin particles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9395487A JPH0739500B2 (en) | 1987-04-16 | 1987-04-16 | Pre-expanded polypropylene resin particles |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63258939A JPS63258939A (en) | 1988-10-26 |
| JPH0739500B2 true JPH0739500B2 (en) | 1995-05-01 |
Family
ID=14096820
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9395487A Expired - Fee Related JPH0739500B2 (en) | 1987-04-16 | 1987-04-16 | Pre-expanded polypropylene resin particles |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0739500B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0325492U (en) * | 1989-07-24 | 1991-03-15 | ||
| US6887639B2 (en) * | 2002-02-22 | 2005-05-03 | Xeikon International N.V. | Liquid toner composition |
| US6924075B2 (en) | 2002-02-22 | 2005-08-02 | Xeikon International N.V. | Dry toner composition |
| JP5910626B2 (en) | 2011-03-17 | 2016-04-27 | 株式会社カネカ | Polypropylene-based resin pre-expanded particles, polypropylene-based in-mold foam-molded article, and method for producing the same |
-
1987
- 1987-04-16 JP JP9395487A patent/JPH0739500B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63258939A (en) | 1988-10-26 |
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