JPH11106576A - Polypropylene resin composition, preexpanded particle prepared therefrom, and production of the particle - Google Patents
Polypropylene resin composition, preexpanded particle prepared therefrom, and production of the particleInfo
- Publication number
- JPH11106576A JPH11106576A JP26873797A JP26873797A JPH11106576A JP H11106576 A JPH11106576 A JP H11106576A JP 26873797 A JP26873797 A JP 26873797A JP 26873797 A JP26873797 A JP 26873797A JP H11106576 A JPH11106576 A JP H11106576A
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- Prior art keywords
- particles
- ethylene
- random copolymer
- propylene random
- resin composition
- 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.)
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- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、含水率が向上した
ポリプロピレン系樹脂組成物、それからなる予備発泡粒
子およびその製法に関する。さらに詳しくは、たとえば
型内発泡成形品の原料として好ましく用いられうるポリ
プロピレン系樹脂組成物からの予備発泡粒子およびその
製法、ならびにそれに用いられる高含水性ポリプロピレ
ン系樹脂組成物に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition having an improved water content, pre-expanded particles comprising the same, and a method for producing the same. More specifically, the present invention relates to, for example, pre-expanded particles from a polypropylene resin composition which can be preferably used as a raw material of an in-mold foam molded article, a method for producing the same, and a highly water-containing polypropylene resin composition used for the same.
【0002】[0002]
【従来の技術および発明が解決しようとする課題】従
来、発泡剤を含有するポリプロピレン系樹脂粒子を水系
分散媒に分散させ、容器内の圧力を発泡剤の蒸気圧以上
に保持しながら樹脂の軟化温度以上に加熱したのち、加
圧容器内より低圧雰囲気中に放出して発泡させる方法が
知られている(たとえば特開昭52−77174号公
報)。2. Description of the Related Art Conventionally, polypropylene resin particles containing a foaming agent are dispersed in an aqueous dispersion medium, and the resin is softened while maintaining the pressure in the container at or above the vapor pressure of the foaming agent. There is known a method in which a material is heated to a temperature or higher and then discharged from a pressurized container into a low-pressure atmosphere and foamed (for example, JP-A-52-77174).
【0003】一般に、ポリプロピレン系樹脂の融点およ
びその温度における水蒸気圧下での含水率は1%(重量
%、以下同様)未満と低く、含水粒子にして予備発泡さ
せることができるようなものではなく、予備発泡粒子の
製造の際には、揮発性有機発泡剤や炭酸ガスなどの発泡
剤が必要とされてきている。[0003] In general, the melting point of a polypropylene resin and the water content under a water vapor pressure at that temperature are as low as less than 1% (wt%, the same applies hereinafter). In the production of pre-expanded particles, a foaming agent such as a volatile organic foaming agent or carbon dioxide has been required.
【0004】しかしながら、揮発性有機発泡剤は、プロ
パン、ブタンなどについては毒性や可燃性など安全性に
問題があり、フロンなどについてはオゾン層破壊といっ
た環境面の問題があり好ましくない。さらに、揮発性発
泡剤を使用すると、発泡倍率のコントロールが困難であ
り、揮発性発泡剤そのものが高価であるためコスト高に
なるという欠点があることも知られている。However, volatile organic foaming agents are not preferred because propane and butane have safety problems such as toxicity and flammability, and chlorofluorocarbons have environmental problems such as destruction of the ozone layer. Further, it is also known that when a volatile foaming agent is used, it is difficult to control the expansion ratio, and the volatile foaming agent itself is expensive, so that there is a disadvantage that the cost is increased.
【0005】一方、炭酸ガスについては、地球温暖化の
原因となるため使用しない方が好ましく、さらに予備発
泡粒子製造時に高圧にしなければならないため、大がか
りな設備を必要とし、設備費が高価になるという欠点が
ある。On the other hand, it is preferable not to use carbon dioxide because it causes global warming. Further, since the pressure must be increased during the production of pre-expanded particles, large equipment is required and the equipment cost is high. There is a disadvantage that.
【0006】前記のごとき欠点を解決する方法として、
無機フィラーを30〜50%含有するポリプロピレン樹
脂粒子を分散媒である水を発泡剤として発泡させる方法
が提案されている(特公昭49−2183号公報)。[0006] As a method of solving the above disadvantages,
A method has been proposed in which polypropylene resin particles containing 30 to 50% of an inorganic filler are foamed using water as a dispersion medium as a foaming agent (Japanese Patent Publication No. 49-2183).
【0007】しかし、この方法では大量の無機フィラー
を使用しているため、型内成形時の粒子同士の融着性が
わるく、またえられる成形体の機械的強度や柔軟性が損
われるといった問題がある。However, in this method, since a large amount of inorganic filler is used, the fusion property between particles during in-mold molding is deteriorated, and the mechanical strength and flexibility of the obtained molded body are impaired. There is.
【0008】一方、同様に分散媒である水を発泡剤とし
てポリプロピレン系樹脂予備発泡粒子をうる方法とし
て、炭素数12〜22の高級脂肪酸金属塩、たとえばA
l塩やZn塩を0.4〜10%含有するエチレン含有率
4〜10%のエチレン−プロピレンランダム共重合体を
基材樹脂として使用する方法(特開昭60−18843
5号公報)、エチレン含有率2〜10%のエチレン−プ
ロピレンランダム共重合体を基材樹脂とし、加熱前初期
容器内圧を無機ガスで5kg/cm2Gとする方法(特
開昭60−221440号公報)が提案されている。On the other hand, similarly, a method of obtaining pre-expanded particles of a polypropylene resin by using water as a dispersing medium as a blowing agent is described as a metal salt of a higher fatty acid having 12 to 22 carbon atoms, for example, A
A method using an ethylene-propylene random copolymer having an ethylene content of 4 to 10% containing 0.4 to 10% of a 1 salt or a Zn salt as a base resin (Japanese Patent Application Laid-Open No. 60-18843)
No. 5), a method in which an ethylene-propylene random copolymer having an ethylene content of 2 to 10% is used as a base resin, and the internal pressure of the initial vessel before heating is adjusted to 5 kg / cm 2 G with an inorganic gas (Japanese Patent Application Laid-Open No. 60-221440) Publication).
【0009】しかしながら、これらの方法で高発泡倍率
の予備発泡粒子をうるには、エチレン−プロピレンラン
ダム共重合体のエチレン含有率を4%以上とし、かつ、
160℃、10時間以上の加熱条件を必要とする。この
ような高温、長時間の加熱を行なうと分散媒中での粒子
同士の融着が起こりやすいうえに、生産性がわるく、経
済的でない。However, in order to obtain pre-expanded particles having a high expansion ratio by these methods, the ethylene content of the ethylene-propylene random copolymer must be 4% or more, and
Heating conditions of 160 ° C. and 10 hours or more are required. When heating is performed at such a high temperature for a long time, fusion of particles in a dispersion medium is likely to occur, and further, productivity is poor and it is not economical.
【0010】したがって、近年、従来必要とされてきた
揮発性有機発泡剤や炭酸ガスなどの発泡剤を使用しなく
ても所望の物性を有するポリプロピレン系樹脂予備発泡
粒子を経済的に製造しうる方法の開発が望まれている。Accordingly, a method for economically producing pre-expanded polypropylene resin particles having desired physical properties without using a volatile organic foaming agent or a foaming agent such as carbon dioxide, which has been conventionally required in recent years, is not required. The development of is desired.
【0011】[0011]
【課題を解決するための手段】本発明は、前記従来の技
術に鑑み、揮発性発泡剤や炭酸ガスなどの従来の発泡剤
を使用しなくても所望の特性を有するポリプロピレン系
樹脂の予備発泡粒子を経済的にうる方法、該方法に用い
ることができる高含水性ポリプロピレン系樹脂組成物お
よび該組成物からなる予備発泡粒子を提供するためにな
されたものであり、(A)エチレン−プロピレンランダ
ム共重合体100部(重量部、以下同様)、(B)エチ
レン−(メタ)アクリル酸共重合体をアルカリ金属イオ
ンで中和してなるアイオノマー樹脂0.05〜20部、
(C)無機充填剤および(または)有機充填剤0〜10
部からなり、該エチレン−プロピレンランダム共重合体
の融点およびその温度における水蒸気圧下での含水率
((A)成分および(B)成分の合計量に対する割合、
以下単に含水率という)が1〜50%であることを特徴
とするポリプロピレン系樹脂組成物(請求項1)、エチ
レン−プロピレンランダム共重合体のエチレン含有率が
0.05〜8%である請求項1記載のポリプロピレン系
樹脂組成物(請求項2)、無機充填剤がタルクである請
求項1記載のポリプロピレン系樹脂組成物(請求項
3)、請求項1記載のポリプロピレン系樹脂組成物から
の粒子を予備発泡させた予備発泡粒子であって、発泡倍
率5〜50倍、独立気泡率80〜100%および平均気
泡率50〜500μmであることを特徴とする予備発泡
粒子(請求項4)、示差走査熱量測定によってえられる
DSC曲線に、エチレン−プロピレンランダム共重合体
の固有ピークより高温側にピークを有する請求項4記載
の予備発泡粒子(請求項5)、ならびに請求項1記載の
ポリプロピレン系樹脂組成物からなる粒子を、密閉容器
内で水系分散媒に分散させ、前記粒子を前記エチレン−
プロピレンランダム共重合体の融点以上、融解終了温度
未満の温度に加熱して、含水率が1〜50%の含水粒子
としたのち、前記密閉容器の一端を解放し、前記含水粒
子および水系分散媒を前記密閉容器の内圧よりも低圧の
雰囲気中に放出させ、前記含水粒子を発泡させることを
特徴とする予備発泡粒子の製法(請求項6)に関する。SUMMARY OF THE INVENTION In view of the above-mentioned prior art, the present invention relates to a pre-expansion of a polypropylene resin having desired characteristics without using a conventional foaming agent such as a volatile foaming agent or carbon dioxide gas. The present invention has been made to provide a method for economically producing particles, a highly water-containing polypropylene resin composition which can be used in the method, and a pre-expanded particle comprising the composition. 100 parts of a copolymer (parts by weight, hereinafter the same), (B) 0.05 to 20 parts of an ionomer resin obtained by neutralizing an ethylene- (meth) acrylic acid copolymer with an alkali metal ion,
(C) inorganic and / or organic fillers 0-10
And the melting point of the ethylene-propylene random copolymer and the water content under steam pressure at that temperature (ratio to the total amount of the components (A) and (B),
(Hereinafter simply referred to as water content) is 1 to 50%, wherein the ethylene content of the ethylene-propylene random copolymer is 0.05 to 8%. The polypropylene resin composition according to claim 1 (claim 2), wherein the inorganic filler is talc; the polypropylene resin composition according to claim 1 (claim 3); Pre-expanded particles obtained by pre-expanding particles, wherein the expansion ratio is 5 to 50 times, the closed cell ratio is 80 to 100%, and the average cell ratio is 50 to 500 μm. The pre-expanded particles according to claim 4, wherein the DSC curve obtained by differential scanning calorimetry has a peak on a higher temperature side than an intrinsic peak of the ethylene-propylene random copolymer. 5), as well as particles made of claims 1 polypropylene resin composition according, dispersed in an aqueous dispersion medium in a closed vessel, the particles of the ethylene -
After heating to a temperature equal to or higher than the melting point of the propylene random copolymer and lower than the melting end temperature to obtain water-containing particles having a water content of 1 to 50%, one end of the closed container is opened, and the water-containing particles and the aqueous dispersion medium are released. Is released into an atmosphere at a pressure lower than the internal pressure of the closed vessel, and the water-containing particles are foamed (claim 6).
【0012】[0012]
【発明の実施の形態】本発明のポリプロピレン系樹脂組
成物には、エチレン−プロピレンランダム共重合体10
0部、エチレン(メタ)アクリル酸共重合体をアルカリ
金属イオンで中和されてなるアイオノマー樹脂0.05
〜20部、ならびに無機充填剤および(または)有機充
填剤0〜10部が含まれる。DESCRIPTION OF THE PREFERRED EMBODIMENTS The polypropylene resin composition of the present invention contains an ethylene-propylene random copolymer 10
0 parts, an ionomer resin obtained by neutralizing an ethylene (meth) acrylic acid copolymer with an alkali metal ion 0.05
-20 parts, and 0-10 parts of inorganic and / or organic fillers.
【0013】前記エチレン−プロピレンランダム共重合
体は、発泡性、成形性、えられる成形体の機械的強度、
耐熱性、柔軟性のバランスにすぐれた予備発泡粒子をう
るために使用される成分であり、また、前記アイオノマ
ー樹脂はポリプロピレン系樹脂組成物の含水率を高める
ために使用される成分であり、さらに、前記無機充填剤
および(または)有機充填剤は、予備発泡時にさらに均
一な気泡を有し、高発泡倍率の予備発泡粒子をうるため
に使用される成分である。The ethylene-propylene random copolymer has foaming properties, moldability, mechanical strength of the obtained molded article,
Heat resistance, a component used to obtain pre-expanded particles having an excellent balance of flexibility, and the ionomer resin is a component used to increase the water content of the polypropylene-based resin composition. The inorganic filler and / or the organic filler are components used for obtaining pre-expanded particles having higher uniform expansion ratio and having more uniform cells at the time of pre-expansion.
【0014】前記エチレン−プロピレンランダム共重合
体中のエチレン含有率は、0.05〜8%、さらには
0.1〜3.8%が好ましい。エチレン含有率が0.0
5%未満のばあいには、融点および結晶化度が高くなり
すぎて予備発泡粒子の発泡性、成形時の融着性が充分で
なくなり、えられる成形体の柔軟性も充分でなくなる傾
向にある。また、8%をこえると、成形体の機械的強
度、耐熱性が充分でなくなる傾向にある。The ethylene content in the ethylene-propylene random copolymer is preferably 0.05 to 8%, more preferably 0.1 to 3.8%. Ethylene content 0.0
If it is less than 5%, the melting point and the degree of crystallinity become too high, so that the foamability of the pre-expanded particles and the fusion property at the time of molding become insufficient, and the flexibility of the obtained molded article tends to be insufficient. is there. If it exceeds 8%, the mechanical strength and heat resistance of the molded article tend to be insufficient.
【0015】また、前記エチレン−プロピレンランダム
共重合体には、接着性、透明性、耐衝撃性、ガスバリア
性、帯電防止性、成形性の改良のために、その他の共重
合可能な共重合成分、たとえば酢酸ビニル、メチルメタ
クリレート、ビニルアルコール、メタクリル酸、塩化ビ
ニルなどが含まれていてもよい。前記その他の共重合成
分の共重合割合は、使用することによる効果をうるため
には2%以上であるのが好ましい。上限は30%であ
る。The ethylene-propylene random copolymer may contain other copolymerizable copolymer components for improving adhesiveness, transparency, impact resistance, gas barrier properties, antistatic properties and moldability. For example, vinyl acetate, methyl methacrylate, vinyl alcohol, methacrylic acid, vinyl chloride and the like may be contained. The copolymerization ratio of the other copolymerization components is preferably 2% or more in order to obtain an effect by using the copolymerization component. The upper limit is 30%.
【0016】前記エチレン−プロピレンランダム共重合
体は、エチレン含有率や測定試料の調整方法などによっ
て異なるが、メルトインデックス(MI)としては、2
30℃において0.5〜30g/10分、さらには2〜
20g/10分のものが好ましく、また曲げ弾性率(J
IS K 7203)としては5000〜20000k
gf/cm2、さらに8000〜16000kgf/c
m2、融点としては125〜165℃、さらには135
〜155℃のものが好ましい。前記MIが0.5g/1
0分未満のばあい、溶融粘度が高すぎて高発泡倍率の予
備発泡粒子がえられにくく、30g/10分をこえるば
あい、発泡時の樹脂の伸びに対する溶融粘度が低く破泡
しやすくなり、予備発泡粒子の連泡率が高くなる傾向に
ある。また、前記曲げ強度が5000kgf/cm2未
満のばあい、機械的強度や耐熱性が不充分となり、20
000kgf/cm2をこえるばあい、えられる発泡成
形体の柔軟性、緩衝特性が不充分となる傾向にある。さ
らに融点が165℃をこえるばあい、成形時の融着性、
緩衝特性が不充分となり、125℃未満のばあい耐熱性
が不充分となる傾向にある。Although the ethylene-propylene random copolymer varies depending on the ethylene content and the method of preparing the measurement sample, the melt index (MI) is 2%.
0.5-30 g / 10 min at 30 ° C.
20 g / 10 min is preferable, and the flexural modulus (J
5,000k to 20,000k for IS K 7203)
gf / cm 2 , and 8000 to 16000 kgf / c
m 2 , melting point of 125 to 165 ° C., and further 135
~ 155 ° C is preferred. The MI is 0.5 g / 1
If it is less than 0 minutes, the melt viscosity is too high to obtain pre-expanded particles having a high expansion ratio, and if it exceeds 30 g / 10 minutes, the melt viscosity with respect to the elongation of the resin at the time of foaming is low and the foam is easily broken. , The open cell ratio of the pre-expanded particles tends to increase. If the bending strength is less than 5000 kgf / cm 2 , the mechanical strength and heat resistance become insufficient,
If it exceeds 000 kgf / cm 2 , the obtained foamed molded article tends to have insufficient flexibility and cushioning properties. Further, when the melting point exceeds 165 ° C, the fusion property at the time of molding,
The buffer characteristics are insufficient, and if the temperature is lower than 125 ° C., the heat resistance tends to be insufficient.
【0017】前記エチレン−プロピレンランダム共重合
体は無架橋の状態で用いてもよく、パーオキサイドや放
射線などにより架橋させて用いてもよい。これらは単独
で用いてもよく、2種以上を併用してもよい。これらの
エチレン−プロピレンランダム共重合体を用いることに
より、高発泡倍率で成形性のよい予備発泡粒子がえられ
やすく、また、えられた予備発泡粒子から製造された成
形体の機械的強度や耐熱性、柔軟性のバランスが良好に
なる点から好ましい。The ethylene-propylene random copolymer may be used in a non-crosslinked state, or may be used after being crosslinked by a peroxide or radiation. These may be used alone or in combination of two or more. By using these ethylene-propylene random copolymers, pre-expanded particles having a high expansion ratio and good moldability can be easily obtained, and the mechanical strength and heat resistance of a molded article manufactured from the obtained pre-expanded particles can be improved. This is preferable because the balance between the properties and the flexibility is improved.
【0018】前記アイオノマー樹脂は、エチレン−(メ
タ)アクリル酸共重合体をアルカリ金属イオンで中和し
たものである。The ionomer resin is obtained by neutralizing an ethylene- (meth) acrylic acid copolymer with an alkali metal ion.
【0019】前記アイオノマー樹脂のベース樹脂となる
エチレン−(メタ)アクリル酸共重合体中のエチレン含
有率は25〜99%、さらには50〜90%が好まし
い。エチレン含有率が25%未満のばあい、エチレン−
プロピレンランダム共重合体中での分散性が充分でなく
なり、予備発泡粒子製造時に容器内で粒子同士の融着が
生じやすくなる。エチレン含有率が99%をこえると、
所定の含水率をうるために大量のアイオノマー樹脂を含
有させなければならず、えられる成形体の機械的強度、
耐熱性、吸水時の寸法安定性が低下する傾向にある。The ethylene- (meth) acrylic acid copolymer serving as the base resin of the ionomer resin has an ethylene content of preferably 25 to 99%, more preferably 50 to 90%. When the ethylene content is less than 25%, ethylene-
Dispersibility in the propylene random copolymer is not sufficient, and particles are likely to fuse together in the container during production of pre-expanded particles. When the ethylene content exceeds 99%,
In order to obtain a predetermined moisture content, a large amount of ionomer resin must be contained, and the mechanical strength of the obtained molded body,
Heat resistance and dimensional stability during water absorption tend to decrease.
【0020】前記エチレン−(メタ)アクリル酸共重合
体には、エチレンおよび(メタ)アクリル酸以外の共重
合成分として(メタ)アクリル酸エステルなどを柔軟
性、低温脆性、成形性改良などのために共重合させても
よい。前記(メタ)アクリル酸エステルの具体例として
は、アクリル酸イソブチル、メタクリル酸メチル、アク
リル酸エチル、メタクリル酸2−エチルヘキシルなどが
あげられる。これらは単独で用いてもよく2種以上を併
用してもよい。The ethylene- (meth) acrylic acid copolymer may contain (meth) acrylic ester as a copolymer component other than ethylene and (meth) acrylic acid to improve flexibility, low-temperature brittleness, and moldability. May be copolymerized. Specific examples of the (meth) acrylate include isobutyl acrylate, methyl methacrylate, ethyl acrylate, 2-ethylhexyl methacrylate, and the like. These may be used alone or in combination of two or more.
【0021】前記の効果をうるためには5%以上用いる
のがよく、20%をこえると所定の含水率をうるために
大量のアイオノマー樹脂を含有させなければならず、え
られる成形体の機械的強度、耐熱性が不充分となりやす
い。In order to obtain the above-mentioned effects, it is preferable to use 5% or more. If it exceeds 20%, a large amount of ionomer resin must be contained in order to obtain a predetermined water content. Strength and heat resistance tend to be insufficient.
【0022】前記エチレン−(メタ)アクリル酸共重合
体の製法についてはとくに制限はなく、高圧ラジカル重
合法などの通常の方法で行なえばよい。The method for producing the ethylene- (meth) acrylic acid copolymer is not particularly limited, and may be a conventional method such as a high-pressure radical polymerization method.
【0023】前記アイオノマー樹脂は、エチレン−(メ
タ)アクリル酸共重合体をアルカリ金属イオンによって
部分的または完全に中和することにより製造される。The ionomer resin is produced by partially or completely neutralizing an ethylene- (meth) acrylic acid copolymer with an alkali metal ion.
【0024】前記アルカリ金属イオンとしては、元素周
期律表Ia族に属するLi、Na、Kのイオンが好まし
い。金属イオン源としては、アルカリ金属の水酸化物、
酸化物、炭酸塩、重炭酸塩、酢酸塩などが使用されう
る。The alkali metal ions are preferably ions of Li, Na and K belonging to Group Ia of the periodic table. As metal ion sources, hydroxides of alkali metals,
Oxides, carbonates, bicarbonates, acetates and the like may be used.
【0025】前記エチレン−(メタ)アクリル酸共重合
体をアイオノマー樹脂にする方法については種々知られ
ているが、代表的な方法としては、押出機などを用いて
溶融混練により前記エチレン−(メタ)アクリル酸共重
合体と前記金属イオン源とを反応させる方法があげられ
る。エチレン−(メタ)アクリル酸共重合体に含まれる
カルボキシル基の中和度としては、30〜90%、さら
には40〜80%の範囲が好ましい。中和度が30%未
満のばあい、所定の含水率をうるためには大量のアイオ
ノマー樹脂を含有させなければならず、えられる成形体
の機械的強度、耐熱性、吸水時の寸法安定性が充分でな
くなる傾向にある。また、中和度が90%をこえるばあ
いには、アイオノマー樹脂の製造が困難になる。Various methods are known for converting the ethylene- (meth) acrylic acid copolymer into an ionomer resin. A typical method is melt kneading using an extruder or the like. ) A method of reacting the acrylic acid copolymer with the metal ion source. The degree of neutralization of the carboxyl group contained in the ethylene- (meth) acrylic acid copolymer is preferably from 30 to 90%, more preferably from 40 to 80%. When the degree of neutralization is less than 30%, a large amount of ionomer resin must be contained in order to obtain a predetermined water content, and the obtained molded article has mechanical strength, heat resistance, and dimensional stability upon water absorption. Tends to be insufficient. When the degree of neutralization exceeds 90%, it becomes difficult to produce an ionomer resin.
【0026】前記アイオノマー樹脂の使用量は、アイオ
ノマー樹脂中の(メタ)アクリル酸含有率、金属イオン
種、中和度などによっても異なるが、通常、所定の含水
率を有するポリプロピレン系樹脂組成物をうるために
は、エチレン−プロピレンランダム共重合体100部に
対して0.05部以上、好ましくは0.5部以上であ
り、また、予備発泡粒子の製造時の生産安定性や発泡特
性を良好にし、えられる成形体にすぐれた成形性、機械
的強度、耐熱性、吸水寸法安定性を付与するためには、
20部以下、好ましくは10部以下である。The amount of the ionomer resin used depends on the (meth) acrylic acid content in the ionomer resin, the type of metal ions, the degree of neutralization, and the like. Usually, a polypropylene resin composition having a predetermined water content is used. In order to obtain, the amount is 0.05 part or more, preferably 0.5 part or more with respect to 100 parts of the ethylene-propylene random copolymer, and has good production stability and foaming characteristics during the production of the pre-expanded particles. In order to impart excellent moldability, mechanical strength, heat resistance and water absorption dimensional stability to the obtained molded body,
It is 20 parts or less, preferably 10 parts or less.
【0027】前記無機充填剤および(または)有機充填
剤のうちの無機充填剤の具体例としては、たとえばタル
ク、炭酸カルシウム、水酸化カルシウムなどがあげられ
る。これらの無機充填剤は、単独で用いてもよく2種以
上を併用してもよい。これらの無機充填剤のなかでは、
タルクが、気泡が均一で高発泡倍率を有する予備発泡粒
子がえられる点から好ましい。Specific examples of the inorganic filler among the inorganic filler and / or the organic filler include talc, calcium carbonate, calcium hydroxide and the like. These inorganic fillers may be used alone or in combination of two or more. Among these inorganic fillers,
Talc is preferred because pre-expanded particles having uniform cells and a high expansion ratio can be obtained.
【0028】前記無機充填剤および(または)有機充填
剤のうちの有機充填剤としては、前記エチレン−プロピ
レンランダム共重合体の融点以上の温度で固体状のもの
であればよく、とくに限定はない。前記有機充填剤の具
体例としては、たとえばフッ素樹脂粉末、シリコーン樹
脂粉末、熱可塑性ポリエステル樹脂粉末などがあげられ
る。これらの有機充填剤は、単独で用いてもよく2種以
上を併用してもよい。The organic filler among the inorganic filler and / or the organic filler is not particularly limited as long as it is solid at a temperature not lower than the melting point of the ethylene-propylene random copolymer. . Specific examples of the organic filler include a fluororesin powder, a silicone resin powder, and a thermoplastic polyester resin powder. These organic fillers may be used alone or in combination of two or more.
【0029】前記充填剤(無機充填剤および有機充填剤
の両方を含む概念である)の平均粒径としては、気泡が
均一で高発泡倍率を有する予備発泡粒子をつくり、また
該予備発泡粒子から機械的強度や柔軟性などにすぐれた
成形体をうる点から0.1〜50μm、さらには0.5
〜10μmであるのが好ましい。前記平均粒子径が50
μmをこえるばあいには、気泡径が大きくなりすぎる傾
向があり、0.1μm未満のばあいには、発泡核点にな
りにくく、成形性が低下する傾向にある。The average particle diameter of the filler (including both an inorganic filler and an organic filler) is determined by preparing pre-expanded particles having uniform cells and a high expansion ratio, and from the pre-expanded particles. 0.1 to 50 μm, and more preferably 0.5 to 50 μm, from the viewpoint of obtaining a molded body having excellent mechanical strength and flexibility.
It is preferably from 10 to 10 μm. The average particle diameter is 50
If it exceeds μm, the cell diameter tends to be too large, and if it is less than 0.1 μm, it tends to be less likely to be a foam nucleus point, and the moldability tends to decrease.
【0030】前記充填剤は必ず使用しなければならない
ものではないが、使用することによる効果、すなわち高
発泡倍率の予備発泡粒子をうるためには、エチレン−プ
ロピレンランダム共重合体100部に対して0.01部
以上、さらには0.1部以上にするのが好ましく、また
予備発泡粒子を成形する際に、すぐれた融着性を発現さ
せ、該予備発泡粒子から機械的強度や柔軟性などにすぐ
れた成形体をうるためには、10部以下、好ましくは5
部以下である。The filler is not necessarily used. However, in order to obtain the effect of using the filler, that is, to obtain pre-expanded particles having a high expansion ratio, 100 parts of the ethylene-propylene random copolymer is used. It is preferably at least 0.01 part, more preferably at least 0.1 part, and when forming the pre-expanded particles, develop excellent fusion properties, and obtain mechanical strength, flexibility, etc. from the pre-expanded particles. 10 parts or less, preferably 5 parts
Part or less.
【0031】前記エチレン−プロピレンランダム共重合
体、アイオノマー樹脂、必要により充填剤などを含有す
る本発明のポリプロピレン系樹脂組成物は、該エチレン
−プロピレンランダム共重合体の融点における水蒸気圧
下での含水率が1〜50%、好ましくは2〜20%とな
るものである。The polypropylene resin composition of the present invention containing the above-mentioned ethylene-propylene random copolymer, ionomer resin, and if necessary, a filler, has a water content under the water vapor pressure at the melting point of the ethylene-propylene random copolymer. Is 1 to 50%, preferably 2 to 20%.
【0032】前記エチレン−プロピレンランダム共重合
体の融点における水蒸気圧下での含水率が1〜50%で
あるため、揮発性発泡剤や炭酸ガスなどの従来の発泡剤
を使用せずとも所望の特性を有する高発泡倍率の予備発
泡粒子がえられる。Since the ethylene-propylene random copolymer has a water content of 1 to 50% under the steam pressure at the melting point, desired characteristics can be obtained without using a conventional blowing agent such as a volatile blowing agent or carbon dioxide gas. Thus, pre-expanded particles having a high expansion ratio and having a high expansion ratio are obtained.
【0033】前記含水率が1%未満のばあい、みかけの
発泡倍率が5倍未満となり、また50%をこえると、粒
子の水系分散媒に対する分散性が低下し、予備発泡粒子
製造時に密閉容器内で粒子が塊状になり、均一な予備発
泡粒子をうることが困難になる。When the water content is less than 1%, the apparent expansion ratio is less than 5 times, and when it exceeds 50%, the dispersibility of the particles in the aqueous dispersion medium is reduced, and the closed container is used during the production of the pre-expanded particles. In this case, the particles are aggregated, and it is difficult to obtain uniform pre-expanded particles.
【0034】なお、前記エチレン−プロピレンランダム
共重合体の融点は、DSCによって10℃/分の昇温速
度で測定したときの融解ピークの頂点の温度から求めら
れ、その温度における水蒸気圧下での含水率は、以下の
ようにして求められる。The melting point of the ethylene-propylene random copolymer is determined from the temperature at the top of the melting peak as measured by DSC at a rate of 10 ° C./min. The rate is determined as follows.
【0035】すなわち、300cc耐圧アンプル中に前
記ポリプロピレン系樹脂組成物の粒子50g、水150
g、分散剤としてパウダー状塩基性第三リン酸カルシウ
ム0.5g、n−パラフィンスルホン酸ソーダ0.03
gを入れ、密閉後に前記エチレン−プロピレンランダム
共重合体の融点に設定した油浴中で3時間加熱処理す
る。さらに室温まで冷却後、取り出し、充分水洗して分
散剤を除去したのち、えられたポリプロピレン系樹脂組
成物の含水粒子の表面の付着水分を除去したものの重量
(X)を求め、ついでその樹脂の融点よりも20℃高い
温度に設定されたオーブン中で3時間乾燥させ、デシケ
ータ中で室温まで冷却させたあとの重量(Y)を求め、
式(I):That is, 50 g of the polypropylene resin composition particles and 150 g of water were placed in a 300 cc pressure-resistant ampoule.
g, 0.5 g of powdery basic tribasic calcium phosphate as a dispersant, 0.03 of sodium n-paraffin sulfonate
g, and after sealing, heat-treat for 3 hours in an oil bath set to the melting point of the ethylene-propylene random copolymer. Further, after cooling to room temperature, it was taken out, washed sufficiently with water to remove the dispersant, and the weight (X) of the obtained water-containing particles of the polypropylene resin composition obtained by removing the adhering water on the surface was determined. The weight (Y) after drying for 3 hours in an oven set at a temperature 20 ° C. higher than the melting point and cooling to room temperature in a desiccator was determined,
Formula (I):
【0036】[0036]
【数1】 (Equation 1)
【0037】にしたがって求められた値をいう。ただ
し、含水率はエチレン−プロピレンランダム共重合体お
よびアイオノマー樹脂に対する割合であるため、充填剤
を用いるばあいには補正する必要がある。Means a value obtained in accordance with However, since the water content is a ratio to the ethylene-propylene random copolymer and the ionomer resin, it is necessary to correct the water content when a filler is used.
【0038】前記エチレン−プロピレンランダム共重合
体、アイオノマー樹脂、必要により充填剤などを含有す
る本発明のポリプロピレン系樹脂組成物は、通常、押出
機、ニーダー、バンバリーミキサー、ロールなどを用い
て溶融混練し、ついで円柱状、楕円柱状、球状、立方体
状、直方体状など予備発泡に利用しやすい所望の粒子形
状に成形するのが好ましい。えられる粒子は通常0.5
〜5mg/粒である。The polypropylene resin composition of the present invention containing the ethylene-propylene random copolymer, the ionomer resin, and, if necessary, a filler is usually melt-kneaded using an extruder, kneader, Banbury mixer, roll, or the like. Then, it is preferable to form the particles into a desired particle shape that can be easily used for preliminary foaming, such as a columnar shape, an elliptical columnar shape, a spherical shape, a cubic shape, and a rectangular parallelepiped shape. The particles obtained are usually 0.5
55 mg / particle.
【0039】前記ポリプロピレン系樹脂組成物からの粒
子は、予備発泡させる際に、密閉容器内で水系分散媒に
分散せしめられ、エチレン−プロピレンランダム共重合
体の軟化温度以上の温度に加熱することにより含水せし
められる。The particles from the polypropylene resin composition are dispersed in an aqueous dispersion medium in a closed vessel during prefoaming, and heated to a temperature equal to or higher than the softening temperature of the ethylene-propylene random copolymer. It is hydrated.
【0040】前記エチレン−プロピレンランダム共重合
体の融点における水蒸気圧下での本発明のポリプロピレ
ン系樹脂組成物の含水率は、1〜50%、好ましくは2
〜20%であるため、粒子の含水率も1〜50%、好ま
しくは2〜20%となる。The water content of the polypropylene resin composition of the present invention under the steam pressure at the melting point of the ethylene-propylene random copolymer is 1 to 50%, preferably 2 to 50%.
Since it is 2020%, the water content of the particles is also 1 to 50%, preferably 2 to 20%.
【0041】前記ポリプロピレン系樹脂組成物からの予
備発泡粒子は、たとえば前記エチレン−プロピレンラン
ダム共重合体、アイオノマー樹脂、必要により使用され
る充填剤などを含有するポリプロピレン系樹脂組成物か
らの粒子を密閉容器内で水系分散媒に分散させ、該粒子
を前記エチレン−プロピレンランダム共重合体の融点以
上、好ましくは融点+5℃以上、融解終了温度未満、好
ましくは融解終了温度−2℃以下の温度に加熱して、含
水率が1〜50%、好ましくは2〜20%のポリプロピ
レン系樹脂組成物の粒子(含水粒子)にしたのち、前記
密閉容器の一端を解放し、前記含水粒子および水系分散
媒を前記密閉容器の内圧よりも低圧の雰囲気中、通常、
大気圧下に放出させ、前記含水粒子を発泡させることに
よりえられる。The pre-expanded particles from the polypropylene-based resin composition are sealed with particles from the polypropylene-based resin composition containing, for example, the above-mentioned ethylene-propylene random copolymer, ionomer resin, and optionally used filler. The particles are dispersed in an aqueous dispersion medium in a vessel, and the particles are heated to a temperature equal to or higher than the melting point of the ethylene-propylene random copolymer, preferably equal to or higher than the melting point + 5 ° C, and lower than the melting end temperature, preferably lower than the melting end temperature -2 ° C. Then, after a water content of 1 to 50%, preferably 2 to 20% of the particles of the polypropylene resin composition (water-containing particles), one end of the closed container is released, and the water-containing particles and the aqueous dispersion medium are In an atmosphere at a lower pressure than the internal pressure of the closed container, usually,
It is obtained by releasing the particles under atmospheric pressure and foaming the water-containing particles.
【0042】なお、前記融解終了温度とは、該粒子3〜
7mg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、ついで10℃/分の降温速度で
40℃付近まで降温したのち、再度10℃/分の昇温速
度で220℃まで昇温し、第2回目の昇温によってえら
れたDSC曲線の吸熱ピークのすそが高温側でベースラ
インの位置に戻ったときの温度のことである。The term "melting end temperature" refers to the temperature of the particles 3 to
7 mg was heated to 220 ° C. at a rate of 10 ° C./min by a differential scanning calorimeter, and then to about 40 ° C. at a rate of 10 ° C./min, and then again at a rate of 10 ° C./min. This is the temperature when the temperature rises to 220 ° C. and the end of the endothermic peak of the DSC curve obtained by the second temperature rise returns to the baseline position on the high temperature side.
【0043】前記密閉容器内で前記粒子を水系分散媒に
分散させる際に、分散剤として、第三リン酸カルシウ
ム、塩基性炭酸マグネシウム、塩基性炭酸亜鉛、炭酸カ
ルシウムなどや、少量の界面活性剤、たとえばドデシル
ベンゼンスルホン酸ソーダ、n−パラフィンスルホン酸
ソーダ、α−オレフィンスルホン酸ソーダなどを使用し
うる。前記分散剤および界面活性剤の使用量については
特別な限定はなく、一般に使用される量使用すればよ
い。When dispersing the particles in an aqueous dispersion medium in the closed container, as a dispersant, tribasic calcium phosphate, basic magnesium carbonate, basic zinc carbonate, calcium carbonate, a small amount of a surfactant, for example, Sodium dodecylbenzene sulfonate, sodium n-paraffin sulfonate, sodium α-olefin sulfonate and the like can be used. There are no particular restrictions on the amounts of the dispersant and surfactant used, and any commonly used amounts may be used.
【0044】なお、前記水系分散媒としては、その代表
的なものとして水があげられるが、水に、必要によりエ
チレングリコール、エチルアルコール、グリセリンなど
の1種以上が含有されているものであってもよい。The water-based dispersion medium is, for example, water. The water contains at least one of ethylene glycol, ethyl alcohol, glycerin and the like, if necessary. Is also good.
【0045】本発明においては、前記含水粒子および水
系分散媒を前記密閉容器の内圧よりも低圧の雰囲気中、
通常、大気圧下に放出させ、前記含水粒子を発泡させる
という手段がとられる。内容物を放出させる際には、容
器内圧を一定範囲に保持するようにチッ素、空気などの
無機ガス(炭酸ガスを除く)などを導入するのがよい。In the present invention, the water-containing particles and the aqueous dispersion medium are mixed in an atmosphere at a pressure lower than the internal pressure of the closed vessel.
Usually, a means is employed in which the hydrated particles are released under atmospheric pressure to foam the hydrated particles. When releasing the contents, it is preferable to introduce an inorganic gas (excluding carbon dioxide gas) such as nitrogen or air so as to keep the internal pressure of the container within a certain range.
【0046】かくしてえられるポリプロピレン系樹脂組
成物を用いた予備発泡粒子は、発泡倍率5〜50倍、好
ましくは7〜30倍、独立気泡率80〜100%、好ま
しくは85〜100%、および平均気泡径50〜500
μm、好ましくは100〜300μmを有する。The pre-expanded particles using the polypropylene resin composition thus obtained have an expansion ratio of 5 to 50 times, preferably 7 to 30 times, a closed cell ratio of 80 to 100%, preferably 85 to 100%, and an average Bubble diameter 50-500
μm, preferably 100-300 μm.
【0047】前記発泡倍率が5倍未満のばあい、えられ
る成形体の柔軟性、緩衝特性などが不充分となり、また
50倍をこえるばあい、えられる成形体の機械的強度、
耐熱性などが不充分となる。また、前記独立気泡率が8
0%未満のばあい、2次発泡力が不足するため、成形時
に融着不良が発生し、えられる成形体の機械的強度など
が低下する。また、前記平均気泡径が50μm未満のば
あい、えられる成形体の形状が歪むなどの問題が生じ、
500μmをこえるばあい、えられる成形体の機械的強
度が低下する。When the expansion ratio is less than 5 times, the flexibility and cushioning properties of the obtained molded article become insufficient, and when it exceeds 50 times, the mechanical strength of the obtained molded article decreases.
Heat resistance becomes insufficient. Further, the closed cell rate is 8
If it is less than 0%, the secondary foaming power is insufficient, so that poor fusion occurs at the time of molding, and the mechanical strength of the obtained molded article is reduced. Further, when the average cell diameter is less than 50 μm, there arises a problem that the shape of the obtained molded article is distorted,
If it exceeds 500 μm, the mechanical strength of the obtained molded article will decrease.
【0048】なお、本発明の予備発泡粒子の示差走査熱
量測定によってえられるDSC曲線には、エチレン−プ
ロピレンランダム共重合体の固有ピークより高温側にピ
ークが存在するのが好ましい。エチレン−プロピレンラ
ンダム共重合体の固有ピークより高温側にピークが存在
するばあいには、えられたポリプロピレン系樹脂予備発
泡粒子の型内成形性がよく、機械的強度や耐熱性の良好
な成形体がえられる。The DSC curve obtained by differential scanning calorimetry of the pre-expanded particles of the present invention preferably has a peak at a higher temperature than the intrinsic peak of the ethylene-propylene random copolymer. When there is a peak on the higher temperature side than the intrinsic peak of the ethylene-propylene random copolymer, the obtained polypropylene-based resin pre-expanded particles have good in-mold moldability, and have good mechanical strength and heat resistance. I can get my body.
【0049】前記予備発泡粒子の示差走査熱量測定によ
ってえられるDSC曲線とは、該予備発泡粒子3〜7m
gを示差走査熱量計によって10℃/分の昇温速度で2
20℃まで昇温したときにえられるDSC曲線のことで
ある。The DSC curve obtained by differential scanning calorimetry of the pre-expanded particles is 3 to 7 m
g at a heating rate of 10 ° C./min by a differential scanning calorimeter.
This is a DSC curve obtained when the temperature is raised to 20 ° C.
【0050】また、前記エチレン−プロピレンランダム
共重合体の固有ピークとは、予備発泡粒子の基材樹脂で
あるエチレン−プロピレンランダム共重合体についての
DSC曲線を求めたばあいにえられる固有の吸熱ピーク
であり、いわゆる融解時の吸熱によるピークと考えられ
ている。一方、高温側のピークとは、前記固有ピークよ
り高温側に現れる吸熱ピークであり、予備発泡粒子製造
時に生じた二次結晶の存在に基づくものと解釈されてい
る。一般に、予備発泡粒子製造時にエチレン−プロピレ
ンランダム共重合体の融点以上、融解終了温度未満の温
度域に加熱、保持することで二次結晶が生成する。前記
固有ピークと高温側のピークとの温度差が大きいことが
望ましく、5℃以上、さらには10℃以上であるのが好
ましい。また、高温側のピークの大きさは5〜60J/
g、さらには15〜35J/gであるのが好ましく、固
有ピークの大きさに対する高温側のピークの大きさの割
合が10〜50%さらには20〜40%であるのが好ま
しい。The intrinsic peak of the ethylene-propylene random copolymer is defined as the intrinsic endotherm obtained when a DSC curve of the ethylene-propylene random copolymer as the base resin of the pre-expanded particles is obtained. This is considered to be a peak, which is a so-called peak due to endotherm during melting. On the other hand, the peak on the high temperature side is an endothermic peak appearing on the higher temperature side than the intrinsic peak, and is interpreted as being based on the presence of secondary crystals generated during the production of the pre-expanded particles. In general, a secondary crystal is generated by heating and maintaining the temperature of the ethylene-propylene random copolymer at or above the melting point and below the melting end temperature during the production of the pre-expanded particles. It is desirable that the temperature difference between the intrinsic peak and the peak on the high temperature side is large, and it is preferably 5 ° C or more, more preferably 10 ° C or more. The peak size on the high temperature side is 5 to 60 J /.
g, more preferably 15 to 35 J / g, and the ratio of the size of the peak on the high temperature side to the size of the intrinsic peak is preferably 10 to 50%, more preferably 20 to 40%.
【0051】本発明のポリプロピレン系樹脂組成物から
の予備発泡粒子は、80%以上の独立気泡率を有するの
で、さらに要すればこの予備発泡粒子を耐圧容器中で加
熱加圧下、一定時間処理することによって空気含浸を行
なったのちに成形用金型に充填し、たとえば蒸気加熱に
より、加熱発泡成形して金型どおりの発泡成形体を製造
してもよい。Since the pre-expanded particles from the polypropylene resin composition of the present invention have a closed cell ratio of 80% or more, if necessary, the pre-expanded particles are treated in a pressure vessel under heat and pressure for a certain period of time. Then, after air impregnation, the mixture may be filled in a molding die, and may be foamed by heating, for example, by steam heating, to produce a foamed molded product according to the mold.
【0052】かくしてえられた発泡成形体は、寸法収縮
率が小さく、形状変形が小さいので、きわめて商品価値
の高いものとなる。The foam molded article thus obtained has a small dimensional shrinkage and a small shape deformation, and therefore has a very high commercial value.
【0053】[0053]
【実施例】つぎに本発明を実施例および比較例に基づい
て説明するが、本発明はこれらの実施例のみに限定され
るものではない。EXAMPLES Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to only these examples.
【0054】実施例1〜7および比較例1〜5 エチレン−プロピレンランダム共重合体(密度0.90
g/cm3、エチレン含有量3%、融点145℃、融解
終了温度160℃、MI=6g/10分)100部に対
し、表1に示すアイオノマー樹脂およびタルク(平均粒
径9.5μm)を表1に示す量添加し、50mmφ単軸
押出機に供給し、溶融混練したのち、直径2.2mmφ
の円筒ダイより押し出し、水冷後カッターで切断し、円
柱状の含水性ポリプロピレン系樹脂組成物からの粒子
(ペレット)(1.8mg/粒)をえた。Examples 1 to 7 and Comparative Examples 1 to 5 Ethylene-propylene random copolymer (density 0.90
g / cm 3 , ethylene content 3%, melting point 145 ° C., melting end temperature 160 ° C., MI = 6 g / 10 min) and 100 parts of the ionomer resin and talc (average particle size 9.5 μm) shown in Table 1. The amount shown in Table 1 was added, and the mixture was supplied to a 50 mmφ single screw extruder, melt-kneaded, and then 2.2 mm in diameter.
Of water-cooled polypropylene-based resin composition to obtain particles (pellets) (1.8 mg / particle).
【0055】つぎに、えられた粒子100部、分散剤と
してパウダー状塩基性第三リン酸カルシウム1部および
n−パラフィンスルホン酸ソーダ0.05部を水300
部とともに密閉容器内に仕込み、容器内容物を約90分
間かけて表1に示す温度まで加熱し、さらに同温度で3
0分間保持した。このときの圧力は、約5.6kg/c
m2Gであった。Next, 100 parts of the obtained particles, 1 part of powdery basic calcium triphosphate as a dispersant and 0.05 part of sodium n-paraffinsulfonic acid were added to 300 parts of water.
And the contents of the container were heated to the temperature shown in Table 1 over about 90 minutes.
Hold for 0 minutes. The pressure at this time is about 5.6 kg / c
m 2 G.
【0056】そののち、容器内の圧力を圧縮空気で表1
に示す圧力まで上昇させ、ただちにこの圧力を保持しつ
つ、密閉容器下部のバルブを開いて水分散物(含水粒子
および水系分散媒)を大気圧下に放出して予備発泡を行
なった。After that, the pressure in the container was adjusted with compressed air as shown in Table 1.
, And while maintaining this pressure, the valve at the bottom of the closed vessel was opened to release the aqueous dispersion (hydrous particles and aqueous dispersion medium) under atmospheric pressure to perform prefoaming.
【0057】つぎに、えられたポリプロピレン系樹脂組
成物からの粒子および予備発泡粒子の物性として、含水
率、発泡倍率、独立気泡率、平均気泡径および気泡のバ
ラツキおよびDSC曲線の固有ピーク温度、高温側ピー
ク温度を以下の方法にしたがって調べた。結果を表1に
示す。Next, the physical properties of the particles and the pre-expanded particles obtained from the polypropylene-based resin composition are as follows: water content, expansion ratio, closed cell ratio, average cell diameter and cell variation, inherent peak temperature of DSC curve, The high temperature side peak temperature was determined according to the following method. Table 1 shows the results.
【0058】(エチレン−プロピレンランダム共重合体
の融点における水蒸気圧下での樹脂組成物の含水率)前
記実施の形態中に示した方法により求めた。(Moisture content of the resin composition under the steam pressure at the melting point of the ethylene-propylene random copolymer) was determined by the method described in the above embodiment.
【0059】(発泡倍率)予備発泡粒子の重量を測定
後、100ccのメスシリンダー中でエタノールに浸漬
し、浸漬前後のメニスカスから発泡粒子の容積を測定し
て真の密度を求め、それで基材粒子の密度を除して算出
した。(Expansion ratio) After measuring the weight of the pre-expanded particles, the particles were immersed in ethanol in a 100 cc measuring cylinder, and the volume of the expanded particles was measured from the meniscus before and after the immersion to determine the true density. Was calculated by dividing the density.
【0060】(独立気泡率)空気比較式比重計(ベック
マン(BECKMAN)社製、930型)を用いて、え
られた予備発泡粒子の独立気泡体積を求め、かかる独立
気泡体積を別途水没法で求めたみかけ体積で除すること
によって独立気泡率を算出した。(Closed cell ratio) The closed cell volume of the obtained pre-expanded particles was determined using an air comparison specific gravity meter (manufactured by BECKMAN, Model 930), and the closed cell volume was separately measured by a submerged method. The closed cell ratio was calculated by dividing by the obtained apparent volume.
【0061】(平均気泡径)えられた予備発泡粒子の中
から任意に30個の予備発泡粒子を取り出し、JIS
K 6402に準拠して気泡径を測定し、平均気泡径
(d)を算出した。(Average cell diameter) From the obtained pre-expanded particles, 30 pre-expanded particles were arbitrarily taken out, and JIS
The cell diameter was measured according to K6402, and the average cell diameter (d) was calculated.
【0062】(気泡のバラツキ)平均気泡径(d)と気
泡径のバラツキを表わす標準偏差(σ)との比(以下、
Uという)を U(%)=(σ/d)×100 で算出した。(Variation of Bubble) The ratio of the average bubble diameter (d) to the standard deviation (σ) representing the variation of the bubble diameter (hereinafter, referred to as “σ”)
U) was calculated by U (%) = (σ / d) × 100.
【0063】Uが小さいほど気泡が均一であることを示
す。The smaller U is, the more uniform the bubbles are.
【0064】Uの値を以下の基準にしたがって分類し、
評価した。The values of U are classified according to the following criteria:
evaluated.
【0065】○:Uの値が35%未満 △:Uの値が35〜45% ×:Uの値が45%をこえる:: The value of U is less than 35% Δ: The value of U is 35 to 45% ×: The value of U exceeds 45%
【0066】(DSC曲線による固有ピーク温度および
高温側ピーク温度)えられた予備発泡粒子5mgを示差
走査熱量計(セイコー電子工業(株)製SSC520
0)によって10℃/分の昇温速度で220℃まで昇温
してDSC曲線を求めた。えられたDSC曲線の低温側
吸熱ピーク(140〜141℃)の頂点の温度を固有ピ
ーク温度とした。(Intrinsic Peak Temperature and Higher Temperature Peak Temperature Based on DSC Curve) 5 mg of the obtained pre-expanded particles were subjected to a differential scanning calorimeter (SSC520 manufactured by Seiko Instruments Inc.).
According to 0), the temperature was raised to 220 ° C. at a rate of 10 ° C./min to obtain a DSC curve. The temperature at the top of the low-temperature endothermic peak (140 to 141 ° C.) of the obtained DSC curve was defined as the intrinsic peak temperature.
【0067】それに対し、高温側吸熱ピーク(160〜
161℃)の頂点の温度を高温側ピーク温度とした。On the other hand, the endothermic peak on the high temperature side (160 to
161 ° C.) was taken as the peak temperature on the high temperature side.
【0068】[0068]
【表1】 [Table 1]
【0069】表1の結果から、実施例1〜7でえられた
予備発泡粒子はいずれも高発泡倍率で、均一微細気泡を
有する独立気泡率の高い予備発泡粒子であることがわか
る。From the results shown in Table 1, it can be seen that all of the pre-expanded particles obtained in Examples 1 to 7 are pre-expanded particles having a high expansion ratio, uniform fine cells, and a high closed cell ratio.
【0070】一方、比較例1〜5でえられた予備発泡粒
子は倍率が5倍未満で気泡バラツキの大きいものである
ことがわかる。On the other hand, it can be seen that the pre-expanded particles obtained in Comparative Examples 1 to 5 have a magnification of less than 5 times and a large cell variation.
【0071】なお、比較例5のものは、収縮が著しくて
独立気泡率、平均気泡径、気泡のバラツキが測定でき
ず、DSC曲線に高温ピークが現れなかった。In Comparative Example 5, the shrinkage was so remarkable that the closed cell ratio, the average cell diameter and the cell dispersion could not be measured, and no high-temperature peak appeared on the DSC curve.
【0072】[0072]
【発明の効果】本発明のポリオレフィン系樹脂組成物を
用いれば、従来の発泡剤を使用しなくても、発泡倍率5
〜50倍、独立気泡率80〜100%および平均気泡径
50〜500μmという、すぐれた性質を有する予備発
泡粒子がえられる。According to the polyolefin resin composition of the present invention, an expansion ratio of 5 can be obtained without using a conventional blowing agent.
Pre-expanded particles having excellent properties of up to 50 times, closed cell ratio of 80 to 100% and average cell diameter of 50 to 500 μm are obtained.
【0073】したがって、本発明の予備発泡粒子を用い
たばあい、えられる型内発泡成形体の収縮率が小さく、
またその成形品の歪みも小さいので、外観にすぐれ、し
かも成形体の生産効率が向上するようになる。したがっ
て、本発明の予備発泡粒子は、寸法精度を要求される車
両用衝撃吸収体などの構造部材、断熱建材などに好まし
く用いられうるものであり、また緩衝包材などの用途に
も有用である。Therefore, when the pre-expanded particles of the present invention are used, the obtained in-mold expanded molded article has a small shrinkage,
Further, since the distortion of the molded product is small, the appearance is excellent, and the production efficiency of the molded product is improved. Therefore, the pre-expanded particles of the present invention can be preferably used for structural members such as shock absorbers for vehicles that require dimensional accuracy, heat-insulating building materials, etc., and are also useful for applications such as cushioning packaging materials. .
Claims (6)
重合体100重量部、(B)エチレン−(メタ)アクリ
ル酸共重合体をアルカリ金属イオンで中和してなるアイ
オノマー樹脂0.05〜20重量部、(C)無機充填剤
および(または)有機充填剤0〜10重量部からなり、
該エチレン−プロピレンランダム共重合体の融点におけ
る水蒸気圧下での含水率((A)成分および(B)成分
の合計量に対する割合)が1〜50重量%であることを
特徴とするポリプロピレン系樹脂組成物。1. An ionomer resin obtained by neutralizing (A) 100 parts by weight of an ethylene-propylene random copolymer and (B) an ethylene- (meth) acrylic acid copolymer with an alkali metal ion. Parts by weight, (C) 0 to 10 parts by weight of an inorganic filler and / or an organic filler,
A polypropylene resin composition, wherein the ethylene-propylene random copolymer has a water content (ratio to the total amount of the components (A) and (B)) at a melting point of 1 to 50% by weight at a melting point. Stuff.
のエチレン含有率が0.05〜8重量%である請求項1
記載のポリプロピレン系樹脂組成物。2. The ethylene-propylene random copolymer has an ethylene content of 0.05 to 8% by weight.
The polypropylene-based resin composition as described in the above.
のポリプロピレン系樹脂組成物。3. The polypropylene resin composition according to claim 1, wherein the inorganic filler is talc.
成物からの粒子を予備発泡させた予備発泡粒子であっ
て、発泡倍率5〜50倍、独立気泡率80〜100%お
よび平均気泡率50〜500μmであることを特徴とす
る予備発泡粒子。4. Pre-expanded particles obtained by pre-expanding particles from the polypropylene resin composition according to claim 1, wherein the expansion ratio is 5 to 50 times, the closed cell ratio is 80 to 100%, and the average cell ratio is 50 to 50. Pre-expanded particles having a size of 500 μm.
C曲線に、エチレン−プロピレンランダム共重合体の固
有ピークより高温側にピークを有する請求項4記載の予
備発泡粒子。5. DS obtained by differential scanning calorimetry
The pre-expanded particles according to claim 4, wherein the C curve has a peak on a higher temperature side than an intrinsic peak of the ethylene-propylene random copolymer.
成物からなる粒子を、密閉容器内で水系分散媒に分散さ
せ、前記粒子を前記エチレン−プロピレンランダム共重
合体の融点以上、融解終了温度未満の温度に加熱して、
含水率((A)成分および(B)成分の合計量に対する
割合)が1〜50重量%の含水粒子としたのち、前記密
閉容器の一端を解放し、前記含水粒子および水系分散媒
を前記密閉容器の内圧よりも低圧の雰囲気中に放出さ
せ、前記含水粒子を発泡させることを特徴とする予備発
泡粒子の製法。6. The particles comprising the polypropylene resin composition according to claim 1 are dispersed in an aqueous dispersion medium in a closed container, and the particles are at or above the melting point of the ethylene-propylene random copolymer but below the melting end temperature. Heated to the temperature of
After making the water-containing particles have a water content (ratio to the total amount of the components (A) and (B)) of 1 to 50% by weight, one end of the closed container is opened, and the water-containing particles and the aqueous dispersion medium are sealed. A method for producing pre-expanded particles, characterized in that the particles are released into an atmosphere at a pressure lower than the internal pressure of the container and the water-containing particles are expanded.
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JP26873797A JP3618525B2 (en) | 1997-10-01 | 1997-10-01 | Pre-expanded particles comprising a polypropylene resin composition and process for producing the same |
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Cited By (4)
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---|---|---|---|---|
BE1013721A3 (en) * | 1999-02-04 | 2002-07-02 | Kaneka Corp | Pre-expanded particle propylene resin, method and device production flow restriction. |
KR100375663B1 (en) * | 2000-12-18 | 2003-03-15 | 삼성종합화학주식회사 | Polypropylene resin composition for extrusion coating |
JP2007514027A (en) * | 2003-12-12 | 2007-05-31 | ビーエーエスエフ アクチェンゲゼルシャフト | Foam molding for molding composed of pelletized foaming filler-containing thermoplastic polymer material |
WO2009075208A1 (en) | 2007-12-11 | 2009-06-18 | Kaneka Corporation | Process for producing expanded polyolefin resin bead and expanded polyolefin resin bead |
-
1997
- 1997-10-01 JP JP26873797A patent/JP3618525B2/en not_active Expired - Fee Related
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE1013721A3 (en) * | 1999-02-04 | 2002-07-02 | Kaneka Corp | Pre-expanded particle propylene resin, method and device production flow restriction. |
KR100375663B1 (en) * | 2000-12-18 | 2003-03-15 | 삼성종합화학주식회사 | Polypropylene resin composition for extrusion coating |
JP2007514027A (en) * | 2003-12-12 | 2007-05-31 | ビーエーエスエフ アクチェンゲゼルシャフト | Foam molding for molding composed of pelletized foaming filler-containing thermoplastic polymer material |
US9018269B2 (en) | 2007-11-12 | 2015-04-28 | Kaneka Corporation | Process for producing expanded polyolefin resin particles and expanded polyolefin resin particles |
WO2009075208A1 (en) | 2007-12-11 | 2009-06-18 | Kaneka Corporation | Process for producing expanded polyolefin resin bead and expanded polyolefin resin bead |
US8513317B2 (en) | 2007-12-11 | 2013-08-20 | Kaneka Corporation | Process for producing expanded polyolefin resin particles and expanded polyolefin resin particles |
EP2754687A1 (en) | 2007-12-11 | 2014-07-16 | Kaneka Corporation | Process for producing expanded polyolefin resin particles and expanded polyolefin resin particles |
US8901182B2 (en) | 2007-12-11 | 2014-12-02 | Kaneka Corporation | Process for producing expanded polyolefin resin particles and expanded polyolefin resin particles |
US9216525B2 (en) | 2007-12-11 | 2015-12-22 | Kaneka Corporation | Process for producing expanded polyolefin resin particles and expanded polyolefin resin particles |
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