JP3281904B2 - Expanded polypropylene resin particles and molded article thereof - Google Patents
Expanded polypropylene resin particles and molded article thereofInfo
- Publication number
- JP3281904B2 JP3281904B2 JP36036791A JP36036791A JP3281904B2 JP 3281904 B2 JP3281904 B2 JP 3281904B2 JP 36036791 A JP36036791 A JP 36036791A JP 36036791 A JP36036791 A JP 36036791A JP 3281904 B2 JP3281904 B2 JP 3281904B2
- Authority
- JP
- Japan
- Prior art keywords
- resin
- temperature
- particles
- polypropylene resin
- expanded
- 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
【０００１】[0001]
【産業上の利用分野】本発明は、高い剛性を持つポリプ
ロピレン系樹脂発泡粒子及びその成形体に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to expanded polypropylene resin particles having high rigidity and molded articles thereof.
【０００２】[0002]
【従来技術及びその課題】従来、ポリプロピレン系樹脂
発泡粒子の融着集合体である型内発泡成形体（以下、Ｐ
Ｐ成形体と称する）は衝撃吸収部材、断熱材、構造材、
浮揚材等の広い分野で使用されている。特にＰＰ成形体
は、本品が出現する以前の発泡体に比べ、安価で軽量、
且つ衝撃吸収性に優れていると共に衝撃を受けた後の回
復性に優れることから、自動車のバンパー用芯材として
広く採用されている。一方、昨今の軽量化と安全性重視
の方向もあって、自動車のバンパー用芯材には軽量で剛
性の高い素材が強く求められている。それゆえ、軽量性
を維持したまま剛性のみを高めたＰＰ成形体の出現が自
動車業界で待たれているが、発泡成形体で剛性を高める
為には発泡倍率を低くする必要があり、そうすると軽量
性を維持することが難しくなるという相反する大きな問
題があり、その解決が切望されるところであった。2. Description of the Related Art Conventionally, in-mold foam molded articles (hereinafter referred to as P
P molded body) is a shock absorbing member, a heat insulating material, a structural material,
It is used in a wide range of fields such as floating materials. In particular, PP moldings are cheaper and lighter than foams before this product appeared,
In addition, it is widely used as a core material for automobile bumpers because of its excellent shock absorbing properties and excellent recoverability after receiving a shock. On the other hand, light weight and high rigidity are strongly demanded for the core material for the bumper of automobiles in light of the recent trend toward weight reduction and safety. Therefore, the appearance of a PP molded article that has increased rigidity while maintaining lightness is expected in the automobile industry. However, in order to increase rigidity in a foam molded article, it is necessary to lower the expansion ratio, and if this is the case, the lightweight There was a contradictory big problem that it was difficult to maintain the sexuality, and a solution to this problem was awaited.
【０００３】[0003]
【発明が解決しようとする課題】本発明は、従来技術に
見られる前記問題を解決し、軽量性を損なわず、剛性を
高めたポリプロピレン系樹脂発泡粒子及びその型内成形
体を提供することを課題とする。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and to provide expanded polypropylene resin particles having increased rigidity without impairing the lightness and a molded article thereof. Make it an issue.
【０００４】[0004]
【課題を解決するための手段】本発明者らは前記課題を
解決するために鋭意研究した結果、特定の引張降伏点強
度を持つポリプロピレン系樹脂に特定の結晶核剤を含有
させ、これを発泡させて形成した発泡粒子を金型内で加
熱融着させることにより、軽量性にすぐれかつ剛性の高
められた発泡粒子成形体が得られることを見出し、本発
明を完成するに至った。即ち、本発明によれば、ポリプ
ロピレン系樹脂を基材樹脂とする発泡粒子において、該
基材樹脂の引張降伏点強度が２５０〜３５０Ｋｇ／ｃｍ
2であり、且つ該基材樹脂に有機アルミニウム系造核剤
を含有させたことを特徴とするポリプロピレン系樹脂発
泡粒子が提供される。また、本発明によれば、請求項１
〜３のいずれかに記載のポリプロピレン系樹脂発泡粒子
を金型内で加熱融着させてなる密度０．０６ｇ／ｃｍ3
以上のポリプロピレン系樹脂発泡粒子成形体が提供され
る。Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a polypropylene resin having a specific tensile yield point strength is mixed with a specific crystal nucleating agent, and this is foamed. The present inventors have found that a foamed molded article having excellent lightness and increased rigidity can be obtained by heating and fusing the foamed particles formed in the mold, and the present invention has been completed. That is, according to the present invention, in a foamed particle using a polypropylene-based resin as a base resin, the base resin has a tensile yield point strength of 250 to 350 kg / cm.
2. Foamed polypropylene-based resin particles are provided, wherein the base resin contains an organic aluminum-based nucleating agent. Also, according to the present invention, claim 1
A density of 0.06 g / cm 3, which is obtained by heat-fusing the expanded polypropylene resin particles according to any one of Items 1 to 3 in a mold.
The above-mentioned molded article of expanded polypropylene resin particles is provided.
【０００５】本発明の基材樹脂となるポリプロピレン系
樹脂は、引張降伏点強度２５０〜３５０Ｋｇ／ｃｍ2の
ものであれば良く、プロピレン単独重合体、プロピレン
−エチレンランダム共重合体、プロピレン−エチレンブ
ロック共重合体、プロピレン−ブテンランダム共重合
体、プロピレン−エチレン−ブテンランダム共重合体等
が使用可能である。無架橋のプロピレン−エチレンラン
ダム共重合体、特にエチレン分１〜１０重量％のものが
発泡性の点で好適である。プロピレンとエチレンを含む
共重合体の場合、剛性面ではエチレン分が少ない方が好
ましい。引張降伏点強度２５０〜３５０Ｋｇ／ｃｍ2の
ポリプロピレン系樹脂は、更に架橋等の方法でその剛性
を向上させると、その樹脂により得られる発泡粒子及び
成形体の剛性も向上する。なお、架橋ポリプロピレン系
樹脂としては、実質的に架橋を有するもの、すなわち、
ゲル分率０．１％以上のものが用いられる。The polypropylene resin used as the base resin in the present invention may have a tensile yield point strength of 250 to 350 kg / cm 2 , and may be a propylene homopolymer, a propylene-ethylene random copolymer, or a propylene-ethylene block. Copolymers, propylene-butene random copolymers, propylene-ethylene-butene random copolymers, and the like can be used. A non-crosslinked propylene-ethylene random copolymer, particularly one having an ethylene content of 1 to 10% by weight, is suitable from the viewpoint of foamability. In the case of a copolymer containing propylene and ethylene, it is preferable that the ethylene content is small in terms of rigidity. When the rigidity of the polypropylene resin having a tensile yield point strength of 250 to 350 Kg / cm 2 is further improved by a method such as crosslinking, the rigidity of expanded particles and molded articles obtained from the resin is also improved. In addition, as the crosslinked polypropylene-based resin, those having substantially crosslinked, that is,
A gel fraction of 0.1% or more is used.
【０００６】ポリプロピレン系樹脂の架橋は、密閉容器
にポリプロピレン系樹脂粒子と水性媒体と架橋剤とジビ
ニルベンゼンを配合し、架橋剤とジビニルベンゼンを樹
脂粒子中に含浸させた後、架橋剤の分解温度に昇温させ
ることによって行うことができる。この場合、架橋剤と
しては、１，１−ビス（ｔ−ブチルパーオキシ）−３，
３，５−トリメチルシクロヘキサン、ジクミルパーオキ
サイド、ｔ−ブチルクミルパーオキサイド、ｎ−ブチル
−４，４−ビス（ｔ−ブチルパーオキシ）バレート、
α，α′−ビス（ｔ−ブチルパーオキシ）−ｍ−ジイソ
プロピルベンゼン、２，５−ジメチル−２，５−ジ（ｔ
−ブチルパーオキシ）ヘキサン等が挙げられる。このよ
うな架橋剤は、樹脂粒子１００重量部に対し０．０５〜
５重量部、好ましくは０．１〜２重量部である。また、
前記ジビニルベンゼンの使用量は、樹脂粒子１００重量
部に対して通常０．０５〜５重量部程度である。[0006] The crosslinking of the polypropylene resin is carried out by blending the polypropylene resin particles, an aqueous medium, a crosslinking agent and divinylbenzene in a closed container, impregnating the crosslinking agent and divinylbenzene into the resin particles, and then decomposing the crosslinking agent. The temperature can be increased by raising the temperature. In this case, as the crosslinking agent, 1,1-bis (t-butylperoxy) -3,
3,5-trimethylcyclohexane, dicumyl peroxide, t-butylcumyl peroxide, n-butyl-4,4-bis (t-butylperoxy) valate,
α, α'-bis (t-butylperoxy) -m-diisopropylbenzene, 2,5-dimethyl-2,5-di (t
-Butylperoxy) hexane and the like. Such a crosslinking agent is used in an amount of 0.05 to 100 parts by weight of the resin particles.
5 parts by weight, preferably 0.1 to 2 parts by weight. Also,
The amount of the divinylbenzene used is usually about 0.05 to 5 parts by weight based on 100 parts by weight of the resin particles.
【０００７】本発明で発泡原料として用いるポリプロピ
レン系樹脂粒子は、従来公知の方法に従ってポリプロピ
レン系樹脂を粒子状に成形することにより得られるが、
本発明では成形時に結晶核剤を添加する。この場合の結
晶核剤の添加方法としては、樹脂粒子中に結晶核剤を含
有させ得る方法であれば任意の方法が採用できるが、一
般には樹脂と結晶核剤とを溶融混練して粒子状に成形す
る方法、あらかじめ多量の結晶核剤を含有させた樹脂ペ
レット（マスターバッチ）と結晶核剤を含まない樹脂ペ
レットを、溶融混練して粒子状にペレット化する方法等
が挙げられる。The polypropylene resin particles used as a foaming raw material in the present invention can be obtained by molding a polypropylene resin into particles according to a conventionally known method.
In the present invention, a nucleating agent is added during molding. As a method of adding the nucleating agent in this case, any method can be adopted as long as the nucleating agent can be contained in the resin particles. And a method in which a resin pellet (master batch) containing a large amount of a crystal nucleating agent in advance and a resin pellet not containing a crystal nucleating agent are melt-kneaded and formed into particles.
【０００８】本発明で用いる有機アルミニウム系造核剤
のうち安息香酸アルミニウム系が特に有効であり、その
具体例としては、例えば、ヒドロキシ−ジ（ｔｅｒｔ−
ブチル安息香酸）アルミニウムが挙げられる。このヒド
ロキシ−ジ（ｔｅｒｔ−ブチル安息香酸）アルミニウム
は、基材樹脂への経晶核剤添加量の調整により剛性をコ
ントロールできる点で特に好ましい。本発明で用いる結
晶核剤添加量は樹脂粒子に対して、一般に０．０５〜
０．５重量％、好ましくは０．１〜０．３重量％であ
り、添加量が過少では本発明の効果が得られず、前記範
囲より大量に加えても添加効果は格別向上しないうえ、
得られる発泡粒子の気泡が微細になりすぎて好ましくな
い。本発明で用いる前記結晶核剤の粒径は、一般的には
０．０１〜５０μｍ、好ましくは０．０１〜１５μｍ程
度である。Among the organoaluminum nucleating agents used in the present invention, aluminum benzoate is particularly effective, and specific examples thereof include, for example, hydroxy-di (tert-
Aluminum butylbenzoate). This aluminum hydroxy-di (tert-butylbenzoate) is particularly preferred in that the rigidity can be controlled by adjusting the amount of the eutectic nucleating agent added to the base resin. The amount of the nucleating agent used in the present invention is generally from 0.05 to
It is 0.5% by weight, preferably 0.1 to 0.3% by weight. If the addition amount is too small, the effect of the present invention cannot be obtained.
It is not preferable because the cells of the obtained expanded particles are too fine. The particle size of the nucleating agent used in the present invention is generally about 0.01 to 50 μm, preferably about 0.01 to 15 μm.
【０００９】本発明では、基材樹脂として、引張降伏点
強度２５０〜３５０Ｋｇ／ｃｍ2のポリプロピレン系樹
脂に有機アルミニウム系結晶核剤を添加したものを使用
するが、基材樹脂の引張降伏点強度が２５０Ｋｇ／ｃｍ
2未満の場合は、圧縮強度等の剛性は向上するもののあ
まりにも基材樹脂の剛性が乏しい為、得られる発泡体の
剛性は通常のものの程度しか期待できない。また、引張
降伏点強度が３５０Ｋｇ／ｃｍ2を越える場合は、有機
アルミニウム系結晶核剤の剛性向上の特別な効果を得る
ことができない。本発明で使用する有機アルミニウム系
結晶核剤は、ポリプロピレン系樹脂中で比較的引張降伏
点強度が小さいものに効果的に作用する。In the present invention, as the base resin, a polypropylene resin having a tensile yield point strength of 250 to 350 kg / cm 2 and an organoaluminum crystal nucleating agent added thereto is used. Is 250Kg / cm
If it is less than 2, although the rigidity such as the compressive strength is improved, the rigidity of the base resin is too low, and the rigidity of the obtained foam can be expected to be only the ordinary rigidity. On the other hand, when the tensile yield point strength exceeds 350 kg / cm 2 , a special effect of improving the rigidity of the organoaluminum-based crystal nucleating agent cannot be obtained. The organoaluminum-based crystal nucleating agent used in the present invention effectively acts on a polypropylene-based resin having relatively low tensile yield strength.
【００１０】本発明における発泡剤としては、揮発性有
機発泡剤及び無機ガス発泡剤が用いられ、また両者の発
泡剤を併用することもできる。この場合、揮発性有機発
泡剤としては従来公知のもの、例えばプロパン、ブタ
ン、ペンタン、ジクロロジフロロメタン、トリクロロフ
ロロメタン等が挙げられ、無機ガス発泡剤としては、窒
素、空気、炭酸ガス、アルゴン、ヘリウム等、種々の常
温ガス状無機物質が挙げられる。本発明で用いる発泡剤
において、揮発性有機発泡剤の使用量は、樹脂１００重
量部に対し２〜２５重量部、好ましくは３〜２０重量部
の割合である。無機ガスを発泡剤とする場合、その容器
内圧力は高圧程好ましいが、一般には１００ｋｇ／ｃｍ
2Ｇ以下の圧力で加圧するのが発泡時の粒子の変形防止
などの面で好ましく、通常は７０ｋｇ／ｃｍ2Ｇ以下の
加圧で行なわれる。また、この無機ガスによる加圧は、
少なくとも１５ｋｇ／ｃｍ2Ｇ、好ましくは２０ｋｇ／
ｃｍ2Ｇ以上である。無機ガスで加圧する時間は、加圧
する圧力によっても変るが樹脂の融点以上では数秒〜１
時間程度であり、通常は５〜３０分程度で十分である。
この無機ガスによる容器内容物の加圧は任意の時期に行
うことができ、容器内容物の充填直後や昇温中、あるい
は発泡温度に達した時期に行うことができる。なお、加
熱による容器内容物の昇温速度は、通常１〜１０℃／
分、好ましくは２〜５℃／分である。As the blowing agent in the present invention, a volatile organic blowing agent and an inorganic gas blowing agent are used, and both blowing agents can be used in combination. In this case, as the volatile organic foaming agent, conventionally known ones, for example, propane, butane, pentane, dichlorodifluoromethane, trichlorofluoromethane and the like can be mentioned, and as the inorganic gas foaming agent, nitrogen, air, carbon dioxide, argon And various normal temperature gaseous inorganic substances such as helium and helium. In the blowing agent used in the present invention, the volatile organic blowing agent is used in an amount of 2 to 25 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the resin. When the inorganic gas is used as the blowing agent, the pressure in the container is preferably as high as possible, but is generally 100 kg / cm.
Pressing at a pressure of 2 G or less is preferable from the viewpoint of preventing deformation of the particles at the time of foaming, and is usually performed at a pressure of 70 kg / cm 2 G or less. Also, pressurization with this inorganic gas
At least 15 kg / cm 2 G, preferably 20 kg / cm 2 G
cm 2 G or more. The time for pressurizing with an inorganic gas varies depending on the pressure to be applied, but is several seconds to 1 at or above the melting point of the resin.
It is about an hour, and usually about 5 to 30 minutes is sufficient.
The pressurization of the contents of the container with the inorganic gas can be performed at any time, and can be performed immediately after filling the contents of the container, during the temperature rise, or at the time when the foaming temperature is reached. The heating rate of the contents of the container by heating is usually 1 to 10 ° C /
Min, preferably 2-5 ° C / min.
【００１１】本発明のポリプロピレン系樹脂発泡粒を得
るには、耐圧容器内に前記した結晶核剤含有ポリプロピ
レン系樹脂粒子、融着防止剤、及び水性媒体（通常は
水）を配合し、発泡剤の存在下で発泡温度まで加熱した
後、容器内容物をその加圧帯域から低圧帯域（通常は大
気圧）に放出させ、発泡剤を含有する樹脂粒子を発泡さ
せる。上記樹脂粒子融着防止剤は、実質的に非水溶性で
かつ加熱時において非溶融性のものであれば、有機及び
無機系を問わず使用可能であるが、一般には無機系のも
のの使用が好ましい。代表的な融着防止剤の例を示す
と、酸化アルミニウム、酸化チタン、水酸化アルミニウ
ム、塩基性炭酸マグネシウム、塩基性炭酸亜鉛、炭酸カ
ルシウム等が挙げられる。このような融着防止剤は、通
常、粒径０．００１〜１００μｍ、好ましくは０．００
１〜３０μｍの微粒子状で用いられる。この融着防止剤
の添加量は、樹脂粒子１００重量部に対し、通常０．０
１〜１０重量部の範囲である。また、耐圧容器を用いて
樹脂粒子を発泡させ発泡粒子を得る場合の発泡温度は、
樹脂の軟化点以上の温度とするのが普通である。なお、
本明細書でいう樹脂の軟化点とは、ＡＳＴＭ−Ｄ６４８
において荷重４．６ｋｇ／ｃｍ2の条件で求められたも
のである。In order to obtain expanded polypropylene resin particles of the present invention, the above-mentioned polypropylene resin particles containing a nucleating agent, a fusion inhibitor, and an aqueous medium (usually water) are blended in a pressure-resistant container. After heating to the foaming temperature in the presence of, the contents of the container are released from its pressurized zone to a low pressure zone (typically atmospheric pressure) to foam the resin particles containing the blowing agent. The resin particle anti-fusing agent can be used regardless of whether it is organic or inorganic, as long as it is substantially water-insoluble and is non-meltable at the time of heating. preferable. Typical examples of the anti-fusing agent include aluminum oxide, titanium oxide, aluminum hydroxide, basic magnesium carbonate, basic zinc carbonate, calcium carbonate and the like. Such an anti-fusion agent usually has a particle size of 0.001 to 100 μm, preferably 0.00
Used in the form of fine particles of 1 to 30 μm. The amount of the anti-fusing agent is usually 0.0% based on 100 parts by weight of the resin particles.
It is in the range of 1 to 10 parts by weight. The foaming temperature when foaming resin particles using a pressure-resistant container to obtain foamed particles,
The temperature is usually higher than the softening point of the resin. In addition,
As used herein, the softening point of the resin refers to ASTM-D648.
In this case, the load was determined under the condition of a load of 4.6 kg / cm 2 .
【００１２】本発明において、容器内容物を高圧帯域か
ら低圧帯域へ放出させる場合の内容物に含まれる発泡性
樹脂粒子中には、二次結晶を含有させるのが好ましい。
この二次結晶の存在する発泡性樹脂粒子は、成形性の良
好な発泡粒子を与える。原料樹脂として無架橋ポリプロ
ピレン系樹脂を用いる場合、この発泡性樹脂粒子中に二
次結晶を存在させることは特に有利である。なお、発泡
性樹脂粒子中における二次結晶の存在は、樹脂発泡粒子
の示差走査熱量測定によって得られるＤＳＣ曲線によっ
て判定することができる。この場合、樹脂発泡粒子の示
差走査熱量測定によって得られるＤＳＣ曲線とは、ポリ
プロピレン系樹脂発泡粒子１〜３ｍｇを示差走査熱量計
によって１０℃／分の昇温速度で２２０℃まで昇温した
ときに得られるＤＳＣ曲線であり、例えば、試料を室温
から２２０℃まで１０℃／分の昇温速度で昇温した時に
得られるＤＳＣ曲線を第１回のＤＳＣ曲線とし、次いで
２２０℃から１０℃／分の降温速度で４０℃付近まで降
温し、再度１０℃／分の昇温速度で２２０℃まで昇温し
た時に得られるＤＳＣ曲線を第２回のＤＳＣ曲線とし、
これらのＤＳＣ曲線から固有ピーク、高温ピークを求め
ることができる。また、この場合、固有ピークとは、発
泡粒子を構成するポリプロピレン系樹脂の、いわゆる融
解時の吸熱によるものであると考えられる。この固有ピ
ークは第１回目のＤＳＣ曲線にも第２回目のＤＳＣ曲線
にも現われ、ピーク頂点の温度は第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ＤＳ
Ｃ曲線で上記固有ピークより高温側に現われる吸熱ピー
クである。発泡性樹脂粒子中における二次結晶の存在
は、樹脂発泡粒子のＤＳＣ曲線にこの高温ピークが現わ
れるか否かで判定され、実質的な高温ピークが現われな
い場合には、樹脂中に二次結晶が存在しないものと判定
される。本発明の場合、前記第２回目のＤＳＣ曲線に現
われる固有ピークの温度と第１回目のＤＳＣ曲線に現わ
れる高温ピークの温度との差は大きいことが望ましく、
第２回目のＤＳＣ曲線の固有ピークの頂点の温度と高温
ピークの頂点の温度との差は５℃以上、好ましくは１０
℃以上である。In the present invention, it is preferable that the expandable resin particles contained in the contents when the contents of the container are discharged from the high pressure zone to the low pressure zone contain secondary crystals.
The expandable resin particles in which the secondary crystals are present give expanded particles having good moldability. When a non-crosslinked polypropylene-based resin is used as a raw material resin, it is particularly advantageous that secondary crystals are present in the expandable resin particles. The presence of the secondary crystals in the expandable resin particles can be determined by a DSC curve obtained by differential scanning calorimetry of the expandable resin particles. In this case, the DSC curve obtained by differential scanning calorimetry of the foamed resin particles refers to the case where 1-3 mg of foamed polypropylene resin particles are heated to 220 ° C at a rate of 10 ° C / min by a differential scanning calorimeter. The DSC curve obtained is, for example, a DSC curve obtained when a sample is heated from room temperature to 220 ° C. at a rate of 10 ° C./min as a first DSC curve, and then from 220 ° C. to 10 ° C./min. The DSC curve obtained when the temperature was lowered to around 40 ° C. at a temperature lowering rate and the temperature was raised to 220 ° C. again at a rate of 10 ° C./min as a second DSC curve,
An intrinsic peak and a high-temperature peak can be obtained from these DSC curves. Also, in this case, the intrinsic peak is considered to be due to the so-called endothermic during melting of the polypropylene resin constituting the expanded particles. This characteristic 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 2
It is below ° C. On the other hand, the high temperature peak is the first DS
This is an endothermic peak appearing on the higher temperature side than the above-mentioned inherent peak in the C curve. The presence of the secondary crystals in the expandable resin particles is determined by whether or not this high-temperature peak appears in the DSC curve of the resin-expanded particles, and when the substantial high-temperature peak does not appear, the secondary crystals are present in the resin. Is determined not to exist. In the case of the present invention, it is desirable that the difference between the temperature of the unique peak appearing in the second DSC curve and the temperature of the high temperature peak appearing in the first DSC curve is large,
The difference between the temperature of the peak of the unique peak of the second DSC curve and the temperature of the peak of the high-temperature peak is 5 ° C. or more, preferably 10 ° C.
° C or higher.
【００１３】次に、樹脂発泡粒子に関し、示差走査熱量
測定によって得られるそのＤＳＣ曲線を図面に示す。図
１は二次結晶を含有する発泡粒子に関するもので、図２
は二次結晶を含有しない発泡粒子に関するものである。
図１及び図２において、曲線１及び曲線２は、試料とし
ての発泡粒子を測定（第１回目の測定）することによっ
て得られたＤＳＣ曲線を示し、曲線１′及び２′は第１
回目の測定後の試料を再び測定（第２回目の測定）する
ことによって得られたＤＳＣ曲線を示す。図１と図２を
対比してわかるように、二次結晶を含有する発泡粒子の
場合、第１回目の測定結果を示す曲線１においては、固
有ピークＢの他に高温ピークＡが現われ、この高温ピー
クＡの存在により発泡粒子に二次結晶が存在することが
確認される。一方、二次結晶を含有しない発砲粒子の場
合、第１回目の測定結果を示す曲線２においては、固有
ピークｂが現われるのみで高温ピークは現われず、発泡
粒子には二次結晶が含まれないことが確認される。図２
の発泡粒子に二次結晶が存在しない理由は、原料未発泡
樹脂粒子が二次結晶化促進温度（融点〜融解終了温度未
満）において十分な時間熱処理を受けず、融解終了温度
以上の温度で発泡されたことによる。なお、２回目の測
定においては図１及び図２の発泡粒子にも高温ピークは
現われず、固有ピークＢ′、ｂ′のみ現われる。Next, the DSC curve of the resin expanded particles obtained by differential scanning calorimetry is shown in the drawing. FIG. 1 relates to expanded particles containing secondary crystals.
Relates to expanded particles containing no secondary crystals.
1 and 2, curves 1 and 2 show DSC curves obtained by measuring (first measurement) the expanded particles as a sample, and curves 1 'and 2' show the first and second curves, respectively.
9 shows a DSC curve obtained by measuring the sample after the second measurement again (second measurement). As can be seen by comparing FIGS. 1 and 2, in the case of the expanded particles containing the secondary crystals, in the curve 1 showing the first measurement result, a high-temperature peak A appears in addition to the intrinsic peak B, The presence of the high temperature peak A confirms that secondary crystals are present in the expanded particles. On the other hand, in the case of the foamed particles containing no secondary crystal, in the curve 2 showing the first measurement result, only the characteristic peak b appears but no high-temperature peak appears, and the expanded particles do not contain the secondary crystal. It is confirmed that. FIG.
The reason why secondary crystals do not exist in the foamed particles is that the raw material unfoamed resin particles do not undergo heat treatment at the secondary crystallization accelerating temperature (melting point to lower than the melting end temperature) for a sufficient time, and foam at a temperature higher than the melting end temperature. It depends. In the second measurement, the high-temperature peak does not appear in the expanded particles of FIGS. 1 and 2, but only the intrinsic peaks B ′ and b ′ appear.
【００１４】本発明において、二次結晶を含む発泡性樹
脂粒子を得る一般的な方法は、耐圧容器内において樹脂
粒子をその融解終了温度以上に昇温することなく、融点
より約２０℃低い温度（融点−２０℃）以上、融解終了
温度未満の温度に充分な時間、通常５〜９０分間、好ま
しくは１５〜６０分間程度保持すればよい。また、この
ようにして二次結晶化した発泡性樹脂粒子を発泡させる
場合、発泡温度は固有ピークの融解終了温度以上であっ
ても、前記高温ピーク以下の温度であれば成形性の良好
な発泡粒子を得ることができる。本発明における発泡温
度は、前記のように、通常、樹脂の軟化点以上の温度で
あるが、好ましい発泡温度は発泡剤の種類によっても変
化し、発泡剤として揮発性有機発泡剤を単独で用いる場
合、その発泡温度は樹脂の融点より約１０℃低い温度以
上、樹脂融点より約５℃高い温度以下、好ましくは樹脂
の融点より約５℃低い温度以上、樹脂の融点より約３℃
高い温度以下である。発泡剤として無機ガスを単独で用
いる場合は、樹脂の融点以上、樹脂の融点より約２０℃
高い温度以下、好ましくは樹脂の融点以上、樹脂の融点
より約１８℃高い温度以下である。揮発性有機発泡剤と
無機ガスを併用する場合は、樹脂の融点より約５℃低い
温度以上、樹脂の融点より約１８℃高い温度以下、好ま
しくは樹脂の融点より約３℃低い温度以上、樹脂の融点
より約１６℃高い温度以下である。In the present invention, a general method for obtaining expandable resin particles containing secondary crystals is to raise the temperature of the resin particles in the pressure vessel to about 20 ° C. lower than the melting point without raising the temperature above the melting end temperature. (Melting point −20 ° C.) or more and lower than the melting end temperature may be maintained for a sufficient time, usually 5 to 90 minutes, preferably about 15 to 60 minutes. When the secondary crystallized foamable resin particles are foamed in this manner, even if the foaming temperature is equal to or higher than the melting end temperature of the intrinsic peak, if the temperature is equal to or lower than the high-temperature peak, foaming with good moldability is performed. Particles can be obtained. The foaming temperature in the present invention is, as described above, usually a temperature equal to or higher than the softening point of the resin, but the preferred foaming temperature varies depending on the type of the foaming agent, and a volatile organic foaming agent is used alone as the foaming agent. In this case, the foaming temperature is not less than about 10 ° C. lower than the melting point of the resin and not more than about 5 ° C. higher than the melting point of the resin, preferably not less than about 5 ° C. lower than the melting point of the resin, and about 3 ° C. below the melting point of the resin.
Below high temperature. When an inorganic gas is used alone as a foaming agent, the melting point of the resin is about 20 ° C. or higher than the melting point of the resin.
The temperature is not higher than the high temperature, preferably not lower than the melting point of the resin and not higher than about 18 ° C. higher than the melting point of the resin. When a volatile organic foaming agent and an inorganic gas are used in combination, the temperature is at least about 5 ° C lower than the melting point of the resin, at most about 18 ° C higher than the melting point of the resin, preferably at least about 3 ° C lower than the melting point of the resin. Below about 16 ° C. higher than the melting point.
【００１５】本発明の発泡粒子及び成形体は、高温ピー
クのエネルギーが１５〜３５Ｊ／ｇ、好ましくは２０〜
３０Ｊ／ｇである結晶構造を持つものが特に好ましい剛
性を示す。この理由は、まだ明確ではないが、高温ピー
クの調整で得られる結晶構造の結晶弾性が発泡体剛性に
多大な寄与をしているためと考えられる。なお、前記高
温ピークのエネルギーは次式によって求めることができ
る。 高温ピークのエネルギー(Ｊ／ｇ)＝高温ピークのチャー
ト上の面積（ｃｍ2）×チャート１ｃｍ2当りのエネルギ
ー(Ｊ／ｃｍ2)÷測定サンプル重量(ｇ) ここで、高温ピークのチャート上の面積とは、例えば図
１において斜線で示すイ、ロ、（ニ）の各点と、高温ピ
ークＡを表すＤＳＣ曲線とによって囲まれる部分の面積
である。但し、イは融解終了後、ロはＤＳＣ曲線におけ
る完全融解部分Ｃ（１７０℃〜２００℃の部分）から低
温側に直接外挿した直線と、２回目のＤＳＣ曲線におけ
る（実線で示す）融解終了温度(二)を垂直に通る直線と
の交点（図１においてニ、ロは重なっている）を示す。
また、本明細書でいう樹脂の融点とは、ＤＳＣ法で約６
ｍｇのサンプルを１０℃／分の速度で２２０℃まで昇温
し、その後１０℃／分で約５０℃まで降温し、再度２２
０℃まで昇温した時に得られるＤＳＣ曲線のピークの温
度であり、また、樹脂の融解終了温度とは、その第２回
目のＤＳＣ曲線の終了温度を意味する。The expanded particles and the molded article of the present invention have a high temperature peak energy of 15 to 35 J / g, preferably 20 to 35 J / g.
Those having a crystal structure of 30 J / g show particularly preferable rigidity. Although the reason is not clear yet, it is considered that the crystal elasticity of the crystal structure obtained by adjusting the high-temperature peak greatly contributes to the foam rigidity. The energy of the high-temperature peak can be obtained by the following equation. Energy of high-temperature peak (J / g) = area on chart of high-temperature peak (cm 2 ) × energy per cm 2 of chart (J / cm 2 ) ÷ weight of measured sample (g) Here, on the chart of high-temperature peak The area is, for example, the area of a portion surrounded by the points A, B, and (D) indicated by oblique lines in FIG. 1 and the DSC curve representing the high temperature peak A. However, a is a line after extrapolation, and b is a straight line extrapolated directly from the complete melting portion C (170 ° C. to 200 ° C.) in the DSC curve to the low temperature side, and is a fusion end (shown by a solid line) in the second DSC curve. The point of intersection with a straight line that passes through the temperature (2) perpendicularly (in FIG. 1, D and B overlap).
Further, the melting point of the resin referred to in this specification is about 6 by the DSC method.
mg sample at a rate of 10 ° C./min to 220 ° C., then at 10 ° C./min to about 50 ° C.
This is the peak temperature of the DSC curve obtained when the temperature is raised to 0 ° C., and the melting end temperature of the resin means the end temperature of the second DSC curve.
【００１６】本発明のポリプロピレン系樹脂発泡粒子成
形体は、密度０．０６ｇ/ｃｍ3以上のものである。その
剛性に関しては、例えば密度０．０８２ｇ／ｃｍ3の成
形体においては、従来のポリプロピレン系樹脂発泡粒子
成形体は５０％圧縮時の圧縮応力が８．５Ｋｇ／ｃｍ2
程度なのに対し、本発明のものは１０．０Ｋｇ／ｃｍ2
以上の値を示し、また、圧縮永久歪も小さくなってい
る。本発明の成型体の密度は０．０６ｇ／ｃｍ3以上で
あるが、これは、密度が０．０６ｇ／ｃｍ3未満の場
合、剛性向上の効果が発揮されなくなることを意味する
のではなく、密度が小さくなればなるほど剛性向上の確
認が難しくなり、密度０．２０ｇ／ｃｍ3未満になると
従来品と剛性面での差が見分けられなくなってしまう為
である。本発明のポリプロピレン系樹脂発泡粒子成形体
の従来公知の発泡粒子型内成形法（ビーズ成形法）に従
って、金型内にその樹脂発泡粒子を充填し、その粒子を
加熱融着させることにより得ることができる。The molded article of expanded polypropylene resin particles according to the present invention has a density of 0.06 g / cm 3 or more. Regarding its rigidity, for example, in a molded article having a density of 0.082 g / cm 3 , the conventional polypropylene resin foamed particle molded article has a compressive stress at the time of 50% compression of 8.5 kg / cm 2.
On the contrary, in the case of the present invention, 10.0 kg / cm 2
The above values are shown, and the compression set is also small. Although the density of the molded article of the present invention is 0.06 g / cm 3 or more, this does not mean that the effect of improving the rigidity is not exhibited when the density is less than 0.06 g / cm 3 , This is because the lower the density, the more difficult it is to confirm the improvement in rigidity. If the density is less than 0.20 g / cm 3 , the difference in rigidity from the conventional product cannot be distinguished. According to a conventionally known method of forming a foamed article of a polypropylene-based resin expanded particle of the present invention into a foamed particle in a mold (bead molding), the resin foamed particles are filled in a mold, and the particles are heated and fused to obtain a molded article. Can be.
【００１７】[0017]
【実施例】次に、本発明を実施例によってさらに詳細に
説明するが、本発明はこの実施例によって限定されるも
のではない。Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
【００１８】実施例１〜５、比較例１〜４ 表１に示す性状の無架橋エチレン−プロピレンランダム
共重合体を使用し、表２に示す結晶核剤を含有させたマ
スターバッチを同表に示す配合となるよう押出機により
練り込み、ストランド状に押出して樹脂ペレットを作成
した。この樹脂ペレット１００重量部に対して水３００
重量部、水酸化アルミニウム０．２重量部、リン酸三カ
ルシウム１５重量部、ドデシルベンゼンスルホン酸ナト
リウム０．２重量部、発泡剤として二酸化炭素（ドライ
アイス）４重量部を配合し、５リットル内での耐圧容器
で撹拌しながら昇温し、１４０℃で３０分間保持し、そ
の後、表２に示す発泡温度で３０分間保持した。次に、
容器内を空気で４５Ｋｇ／ｃｍ2Ｇに保ちながら、内容
物を容器の一端から大気中に放出して発泡粒子を得た。
この時の発泡粒子の嵩倍率を表２に示す。次に、この発
泡粒子を２Ｋｇ／ｃｍ2の空気で２４時間加圧処理して
発泡粒子の内圧を高めた後、５０×３００×３００ｍｍ
の内寸法を持つ成形用金型に充填し、３．２ｋｇ／ｃｍ
2Ｇの蒸気で加熱して発泡粒子成型体を得た。得られた
成形体を６０℃のオーブンで２４時間乾燥し、常温まで
徐冷した後、各発泡粒子成形体の５０％圧縮時の圧縮強
度を測定した結果を表２に併せて示す。また、発泡粒子
及びその成型体の示差走査熱量測定によって得られたＤ
ＳＣ曲線の高温ピークエネルギー、圧縮永久歪率、成型
体の発泡倍率を表２に併せて示す。Examples 1 to 5 and Comparative Examples 1 to 4 Master batches containing a non-crosslinked ethylene-propylene random copolymer having the properties shown in Table 1 and containing a nucleating agent shown in Table 2 are shown in the table. The mixture was kneaded with an extruder so as to have the composition shown, and extruded into strands to prepare resin pellets. Water 300 per 100 parts by weight of this resin pellet
5 parts by weight, 0.2 parts by weight of aluminum hydroxide, 15 parts by weight of tricalcium phosphate, 0.2 parts by weight of sodium dodecylbenzenesulfonate, and 4 parts by weight of carbon dioxide (dry ice) as a blowing agent The mixture was heated at 140 ° C. for 30 minutes while being stirred in a pressure vessel at, and then kept at the foaming temperature shown in Table 2 for 30 minutes. next,
While maintaining the inside of the container at 45 Kg / cm 2 G with air, the contents were discharged into the atmosphere from one end of the container to obtain expanded particles.
Table 2 shows the bulk ratio of the expanded particles at this time. Next, the foamed particles were subjected to a pressure treatment with 2 kg / cm 2 air for 24 hours to increase the internal pressure of the foamed particles.
3.2kg / cm
The mixture was heated with 2 G steam to obtain a foamed particle molded body. The obtained molded body was dried in an oven at 60 ° C. for 24 hours and gradually cooled to room temperature, and the results of measuring the compressive strength of each foamed particle molded body at 50% compression are also shown in Table 2. In addition, D obtained by differential scanning calorimetry of the expanded particles and the molded product thereof
Table 2 also shows the high-temperature peak energy of the SC curve, the compression set, and the expansion ratio of the molded product.
【００１９】[0019]
【表１】 [Table 1]
【００２０】[0020]
【表２】 [Table 2]
【００２１】なお、前記に示したヒドロキシージ（ｔｅ
ｒｔ−ブチル安息香酸）アルミニウムは、次の構造式で
表わされる。 Incidentally, the hydroxy di (te
Aluminum (rt-butylbenzoate) is represented by the following structural formula.
【００２２】[0022]
【発明の効果】本発明のポリプロピレン系樹脂発泡粒子
及びその成形体は、その基材樹脂として引張り降伏点強
度２５０〜３５０ｋｇ／ｃｍ2を示すポリプロピレン系
樹脂に有機アルミニウム系造核剤を添加したものを用い
たことから、軽量性にすぐれるとともに、高い剛性を有
する。また、本発明のポリプロピレン系樹脂粒子におい
て、その樹脂に二次結晶を含有させたものは、その剛性
において一層すぐれたものである。The foamed polypropylene resin particles and the molded article of the present invention are obtained by adding an organic aluminum nucleating agent to a polypropylene resin having a tensile yield point strength of 250 to 350 kg / cm 2 as a base resin. Since it is used, it has excellent lightness and high rigidity. In the polypropylene-based resin particles of the present invention, those containing secondary crystals in the resin are more excellent in rigidity.
【図１】二次結晶の存在する発泡粒子について示差走査
熱量測定して得られたＤＳＣ曲線を示し、曲線１は第１
回目のＤＳＣ曲線を、曲線１′は第２回目のＤＳＣ曲線
を示している。FIG. 1 shows a DSC curve obtained by performing differential scanning calorimetry on expanded particles in which secondary crystals are present.
The first DSC curve is shown, and the curve 1 'is the second DSC curve.
【図２】二次結晶の存在しない発泡粒子について示差走
査熱量測定して得られたＤＳＣ曲線を示し、曲線２は第
１回目のＤＳＣ曲線を、曲線２′は第２回目のＤＳＣ曲
線を示している。FIG. 2 shows a DSC curve obtained by differential scanning calorimetry of expanded particles having no secondary crystals, curve 2 shows a first DSC curve, and curve 2 ′ shows a second DSC curve. ing.
Ａ 高温ピーク Ｂ，Ｂ′、ｂ，ｂ′ 固有ピーク A High temperature peak B, B ', b, b' Specific peak
フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) C08J 9/16,9/232 Continuation of front page (58) Field surveyed (Int. Cl. 7 , DB name) C08J 9/16, 9/232
Claims (4)
発泡粒子において、該基材樹脂の引張降伏点強度が２５
０〜３５０Ｋｇ／ｃｍ2であり、且つ該基材樹脂に有機
アルミニウム系造核剤を含有させたことを特徴とするポ
リプロピレン系樹脂発泡粒子。1. A foamed particle comprising a polypropylene resin as a base resin, wherein the base resin has a tensile yield point strength of 25%.
Foamed polypropylene resin particles having a weight of 0 to 350 kg / cm 2 and an organic aluminum nucleating agent contained in the base resin.
脂が、示差走査熱量測定によって得られるＤＳＣ曲線
（ただし、ポリプロピレン系樹脂発泡粒子を、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、且つ前記高温ピークのエネ
ルギーが１５〜３５Ｊ／ｇである結晶構造を持つことを
特徴とする請求項１記載のポリプロピレン系樹脂発泡粒
子。2. A DSC curve obtained by differential scanning calorimetry (provided that the polypropylene-based resin constituting the expanded particles has a DSC curve obtained by differential scanning calorimetry (provided that the polypropylene-based resin expanded particles are measured at a temperature rising rate of 10 ° C./min by a differential scanning calorimeter at 220 ° C.). (A DSC curve obtained when the temperature is raised to the maximum), a unique peak unique to the polypropylene resin and a high temperature peak higher than the temperature of the unique peak appear, and the energy of the high temperature peak is 15 to 35 J / g. 2. The expanded polypropylene resin particles according to claim 1, having a certain crystal structure.
−ジ（ｔｅｒｔ−ブチル安息香酸）アルミニウムである
ことを特徴とする請求項１または２記載のポリプロピレ
ン系樹脂発泡粒子。3. The expanded polypropylene resin particles according to claim 1, wherein the organoaluminum nucleating agent is aluminum hydroxy-di (tert-butylbenzoate).
ロピレン系樹脂発泡粒子を金型内で加熱融着させてなる
密度０．０６ｇ／ｃｍ3以上のポリプロピレン系樹脂発
泡粒子成形体。4. A molded article of expanded polypropylene resin particles having a density of 0.06 g / cm 3 or more obtained by heat-fusing the expanded polypropylene resin particles according to claim 1 in a mold.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP36036791A JP3281904B2 (en) | 1991-12-28 | 1991-12-28 | Expanded polypropylene resin particles and molded article thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP36036791A JP3281904B2 (en) | 1991-12-28 | 1991-12-28 | Expanded polypropylene resin particles and molded article thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05179049A JPH05179049A (en) | 1993-07-20 |
| JP3281904B2 true JP3281904B2 (en) | 2002-05-13 |
Family
ID=18469105
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP36036791A Expired - Fee Related JP3281904B2 (en) | 1991-12-28 | 1991-12-28 | Expanded polypropylene resin particles and molded article thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3281904B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110128700A (en) * | 2019-05-31 | 2019-08-16 | 上海欣鑫化工有限公司 | A kind of organic carboxyl acid salt nucleating agent and its preparation process |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08277340A (en) * | 1995-04-05 | 1996-10-22 | Jsp Corp | Foam grain of polypropylene homopolymer and molded product using the same |
| JP4083807B2 (en) * | 1996-08-12 | 2008-04-30 | 株式会社ジェイエスピー | Automotive bumper core |
| JP4519335B2 (en) | 2001-02-01 | 2010-08-04 | 株式会社カネカ | Polyolefin resin pre-expanded particles and method for producing the same |
| JP4907118B2 (en) * | 2005-07-19 | 2012-03-28 | 株式会社カネカ | Method for producing polypropylene resin pre-expanded particles |
-
1991
- 1991-12-28 JP JP36036791A patent/JP3281904B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110128700A (en) * | 2019-05-31 | 2019-08-16 | 上海欣鑫化工有限公司 | A kind of organic carboxyl acid salt nucleating agent and its preparation process |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05179049A (en) | 1993-07-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4777000A (en) | Production method of expansion-molded article of polypropylene resin | |
| US4626555A (en) | Polypropylene foamed particles | |
| JP2887291B2 (en) | Method for producing expanded polyolefin resin particles | |
| EP0071981B1 (en) | Foamed molded articles of polypropylene resin | |
| US4695593A (en) | Prefoamed propylene polymer-base particles, expansion-molded article produced from said particles and production process of said article | |
| US5032620A (en) | Propylene resin foamed particles and foamed mold article | |
| JP3692760B2 (en) | Method for producing foamed molded product in polypropylene resin mold | |
| JP3281904B2 (en) | Expanded polypropylene resin particles and molded article thereof | |
| JP3171272B2 (en) | Method for producing expanded polymer particles | |
| JPS614738A (en) | Preparation of foamed polypropylene resin particle | |
| JPS6259642A (en) | Pre-expanded particle of modified polyethylene resin and production thereof | |
| JPH0510374B2 (en) | ||
| JPH0386737A (en) | Production of foamed polyolefin resin particle | |
| JP2880834B2 (en) | Expanded polypropylene resin particles, in-mold molded product, energy absorbing material, and core material for automobile bumpers | |
| JP2603858B2 (en) | Method for producing spherical polyethylene expanded particles | |
| JPH02158441A (en) | Core material for automobile bumper | |
| JP3218333B2 (en) | Expanded polyolefin resin particles and method for producing the same | |
| JP3195675B2 (en) | Method for producing expanded polyolefin resin particles | |
| EP0337584B1 (en) | Process for the production of expanded particles of a polypropylene resin | |
| JP2000219766A (en) | Foamed polypropylene resin molding and automotive interior furnishing material | |
| JPH08113667A (en) | Molded linear low-density polyethylene resin foam and its production | |
| JPS625455B2 (en) | ||
| JP2826769B2 (en) | Method for producing expanded polymer particles | |
| JPS6344778B2 (en) | ||
| JPS6341942B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 6 Free format text: PAYMENT UNTIL: 20080301 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090301 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090301 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100301 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Year of fee payment: 8 Free format text: PAYMENT UNTIL: 20100301 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110301 Year of fee payment: 9 |
|
| LAPS | Cancellation because of no payment of annual fees |