JPS6324616B2 - - Google Patents
Info
- Publication number
- JPS6324616B2 JPS6324616B2 JP57093099A JP9309982A JPS6324616B2 JP S6324616 B2 JPS6324616 B2 JP S6324616B2 JP 57093099 A JP57093099 A JP 57093099A JP 9309982 A JP9309982 A JP 9309982A JP S6324616 B2 JPS6324616 B2 JP S6324616B2
- Authority
- JP
- Japan
- Prior art keywords
- ethylene
- particles
- propylene copolymer
- dispersion medium
- 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
Links
- 239000002245 particle Substances 0.000 claims description 43
- 229920001577 copolymer Polymers 0.000 claims description 26
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 14
- 239000002612 dispersion medium Substances 0.000 claims description 14
- 239000004604 Blowing Agent Substances 0.000 claims description 9
- 239000000377 silicon dioxide Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 5
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 4
- 239000005977 Ethylene Substances 0.000 claims description 4
- 239000006260 foam Substances 0.000 claims description 4
- 239000002904 solvent Substances 0.000 claims description 4
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 claims description 2
- 229920005989 resin Polymers 0.000 description 15
- 239000011347 resin Substances 0.000 description 15
- 238000010438 heat treatment Methods 0.000 description 11
- 239000000047 product Substances 0.000 description 11
- 238000000034 method Methods 0.000 description 7
- 238000000465 moulding Methods 0.000 description 5
- 238000005187 foaming Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000002270 dispersing agent Substances 0.000 description 3
- 230000004927 fusion Effects 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- RGSFGYAAUTVSQA-UHFFFAOYSA-N Cyclopentane Chemical compound C1CCCC1 RGSFGYAAUTVSQA-UHFFFAOYSA-N 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 229920001400 block copolymer Polymers 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- PXBRQCKWGAHEHS-UHFFFAOYSA-N dichlorodifluoromethane Chemical compound FC(F)(Cl)Cl PXBRQCKWGAHEHS-UHFFFAOYSA-N 0.000 description 2
- 235000019404 dichlorodifluoromethane Nutrition 0.000 description 2
- 239000004088 foaming agent Substances 0.000 description 2
- 229910001872 inorganic gas Inorganic materials 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 229920005990 polystyrene resin Polymers 0.000 description 2
- DDMOUSALMHHKOS-UHFFFAOYSA-N 1,2-dichloro-1,1,2,2-tetrafluoroethane Chemical compound FC(F)(Cl)C(F)(F)Cl DDMOUSALMHHKOS-UHFFFAOYSA-N 0.000 description 1
- PMPVIKIVABFJJI-UHFFFAOYSA-N Cyclobutane Chemical compound C1CCC1 PMPVIKIVABFJJI-UHFFFAOYSA-N 0.000 description 1
- 239000004338 Dichlorodifluoromethane Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 238000010793 Steam injection (oil industry) Methods 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- NEHMKBQYUWJMIP-NJFSPNSNSA-N chloro(114C)methane Chemical compound [14CH3]Cl NEHMKBQYUWJMIP-NJFSPNSNSA-N 0.000 description 1
- HRYZWHHZPQKTII-UHFFFAOYSA-N chloroethane Chemical compound CCCl HRYZWHHZPQKTII-UHFFFAOYSA-N 0.000 description 1
- 238000007334 copolymerization reaction Methods 0.000 description 1
- 229940042935 dichlorodifluoromethane Drugs 0.000 description 1
- UMNKXPULIDJLSU-UHFFFAOYSA-N dichlorofluoromethane Chemical compound FC(Cl)Cl UMNKXPULIDJLSU-UHFFFAOYSA-N 0.000 description 1
- 229940099364 dichlorofluoromethane Drugs 0.000 description 1
- 229940087091 dichlorotetrafluoroethane Drugs 0.000 description 1
- HQQADJVZYDDRJT-UHFFFAOYSA-N ethene;prop-1-ene Chemical group C=C.CC=C HQQADJVZYDDRJT-UHFFFAOYSA-N 0.000 description 1
- 229960003750 ethyl chloride Drugs 0.000 description 1
- 229920005674 ethylene-propylene random copolymer Polymers 0.000 description 1
- 238000010097 foam moulding Methods 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- 150000008282 halocarbons Chemical class 0.000 description 1
- DMEGYFMYUHOHGS-UHFFFAOYSA-N heptamethylene Natural products C1CCCCCC1 DMEGYFMYUHOHGS-UHFFFAOYSA-N 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229940073584 methylene chloride Drugs 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- 150000002894 organic compounds Chemical group 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- UOURRHZRLGCVDA-UHFFFAOYSA-D pentazinc;dicarbonate;hexahydroxide Chemical compound [OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[Zn+2].[Zn+2].[Zn+2].[Zn+2].[Zn+2].[O-]C([O-])=O.[O-]C([O-])=O UOURRHZRLGCVDA-UHFFFAOYSA-D 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 229920005672 polyolefin resin Polymers 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 229920005604 random copolymer Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000005070 ripening Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- CYRMSUTZVYGINF-UHFFFAOYSA-N trichlorofluoromethane Chemical compound FC(Cl)(Cl)Cl CYRMSUTZVYGINF-UHFFFAOYSA-N 0.000 description 1
- 229940029284 trichlorofluoromethane Drugs 0.000 description 1
Description
本発明はエチレン−プロピレン共重合体予備発
泡粒子の製造法に関するものである。
エチレン−プロピレン共重合体からなる発泡成
形体は、ポリスチレン系樹脂の発泡成形体と比べ
ると柔軟かつしなやかで、低温特性や耐薬品性も
すぐれているという特徴があるため、最近ポリス
チレン系のものにかわつて多くの分野で利用され
るようになつた。しかしながら、この共重合体に
限らずポリオレフイン系樹脂に共通の欠点である
が、ポリスチレン系樹脂の場合よりも発泡成形が
やや困難であるため、そのすぐれた特性を十分に
発揮させるのが難しいという問題点が指摘されて
いる。
たとえば、発泡成形体の有利な製造法の一つと
して特公昭56−1344号の発明による予備発泡粒子
を経由する方法、すなわち樹脂粒子に揮発性溶剤
型発泡剤を吸収させ、更に分散媒と共に密閉容器
中で加圧下に加熱したのち分散媒と共に容器内よ
りも低圧の雰囲気に放出して発泡させることによ
り得られる予備発泡粒子を、次いで成形用型内に
充填し、水蒸気吹込み等の手段により加熱して再
発泡させるとともに発泡粒子同士を融着させて成
形する方法があるが、この方法によつてエチレン
−プロピレン共重合体の発泡成形体を製造する
と、成形時に収縮が大きいため、得られる成形体
は発泡倍率から期待されるほどの柔軟性を示さな
いし、他の物性においても十分なものではない。
本発明者らは上述のようなエチレン−プロピレ
ン共重合体の成形困難性につき種々検討した結
果、その原因が、エチレン−プロピレン共重合体
の予備発泡粒子に特有の微細な気泡にあることを
知つた。そして更に研究を重ねた結果、エチレン
−プロピレン共重合体の場合に気泡径が小さくな
るのは必ずしもエチレン−プロピレン共重合体固
有の性質に基づくものではなくて、この共重合体
に普通に添加されている無機質添加物、特にシリ
カに起因するものであることを知つた。
本発明は上記知見に基づき完成されたものであ
つて、シリカ含有量が0.1％未満であるエチレン
−プロピレン共重合体粒子に揮発性溶剤型発泡剤
を吸収させて分散媒と共に密閉容器中で軟化温度
以上の温度に加熱し、次いでこれを分散媒と共に
容器内よりも低圧の雰囲気に放出して発泡させる
ことを特徴とする粗大気泡を有するエチレン−プ
ロピレン共重合体予備発泡粒子の製造法を提供す
るものである。
ここで「粗大気泡を有するエチレン−プロピレ
ン共重合体予備発泡粒子」とは発泡倍率が３倍以
上でありかつそのほぼ中心を通る切断面を観察す
るとき気泡数が平均150個／mm2以下であるような、
比較的大きな直径の気泡を有するエチレン−プロ
ピレン共重合体予備発泡粒子である。このような
予備発泡粒子は、前述の微細な気泡を有するエチ
レン−プロピレン共重合体予備発泡粒子（平均気
泡数は150個／mm2を越え、通常300個／mm2以上であ
る）に比べると多くの点ですぐれた性質の発泡成
形体を与える。
本発明で用いるエチレン−プロピレン共重合体
は、ランダム共重合体でもブロツク共重合体でも
よく、またこれらの架橋したものであつてもよ
い。しかしながら、特に好ましいエチレン−プロ
ピレン共重合体は、エチレン成分の共重合比が10
重量％以下で、かつ無架橋のものである。そして
シリカの含有率は0.1％未満でなければならない。
シリカ含有率が0.1％以上のものからは、租大気
泡を有するものを得ることができない。シリカが
0.05％以下のものは気泡数が100個／mm2以下のも
のを容易に与えるので特に好ましい。
原料の樹脂が上述のように限定されることを除
けば、本発明の方法は前記特公昭56−1344号公報
に記載されている予備発泡粒子の製造法と本質的
に異なるものではないが、以下にその概要を説明
する。
エチレン−プロピレン共重合体に吸収させる揮
発性溶剤型発泡剤としては、エチレン−プロピレ
ン共重合体粒子に浸透することのできる低沸点の
有機化合物（通常−50〜110℃程度の沸点を有す
るもの）が適当である。その具体例としては次の
ようなものがある：プロパン、ブタン、ペンタ
ン、ヘキサン、ヘプタン等の脂肪族炭化水素類；
シクロブタン、シクロペンタン等の環式脂肪族炭
化水素類；トリクロロフルオロメタン、ジクロロ
フルオロメタン、ジクロロジフルオロメタン、ジ
クロロテトラフルオロエタン、メチルクロライ
ド、エチルクロライド、メチレンクロライド等の
ハロゲン化炭化水素類。
発泡剤をエチレン−プロピレン共重合体粒子に
吸収させるには、常温で、または加熱下に、両者
を接触させればよいが、この工程は、独立に行う
ほか樹脂粒子を分散媒と共に密閉容器中で加熱す
る工程と同時に行なつてもよい。その場合は、未
処理の樹脂粒子、発泡剤および分散媒を密閉容器
に仕込み、攪拌しながら昇温する。あるいは密閉
容器内で未処理樹脂粒子および分散媒を加熱し、
所定の温度に達するまでの任意の段階で発泡剤を
密閉容器内に注入し混合する。
分散媒としてはエチレン−プロピレン共重合体
を溶解しない有機溶媒、たとえばエチレングリコ
ール、グリセリン、メタノール、エタノール等の
ほか、水を用いることができる。
分散媒に樹脂粒子を分散させて密閉容器中で加
熱するに当り、分散媒にはほかに分散剤たとえば
酸化アルミニウム、酸化チタン、塩基性炭酸マグ
ネシウム、塩基性炭酸亜鉛、炭酸カルシウム等の
微粉末を添加して樹脂粒子の融着を防止してもよ
い。分散剤の添加量は、樹脂粒子100重量部当り
通常0.01〜10重量部程度にすることが望ましい。
加熱工程における加熱温度は、樹脂の軟化温度
以上、樹脂粒子間の融着が起こらない程度の温度
であればよい。好ましい温度はもちろんエチレン
−プロピレン共重合体の種類により異なるが、通
常90〜170℃である。この温度が高すぎると粒子
同士の融着により次の発泡工程に移すことが困難
になるばかりでなく、気泡の破壊が起こつて独立
気泡率の低い発泡粒子となつてしまう。また加熱
時間は特に限定されないが、この加熱中に発泡剤
を吸収させる場合は、発泡剤が粒子中に均一に吸
収されるまで処理する必要があること、いうまで
もない。
このあと、密閉容器の内容物を容器内圧よりも
低い圧力の雰囲気に放出して発泡剤を気化させる
ことにより樹脂粒子を発泡させる。分散媒として
水を用いた場合、上記のようにして発泡させる雰
囲気はふつう常圧の大気でよい。
以上のような本発明の方法によれば、見掛けの
発泡倍率が３〜60倍で平均気泡数が150個／mm2以
下の、粗大気泡を夢するエチレン−プロピレン共
重合体予備発泡粒子を容易に製造することができ
る。そしてこのエチレン−プロピレン共重合体予
備発泡粒子は、従来の予備発泡粒子と全く同様に
して型内成形することができ、その際、気泡が粗
大であることに基づき、次のような有利な性質を
示す。
(イ) 収縮が少なく、したがつて粒子の融着が確実
に行われるから、得られる発泡成形体の物性お
よび表面の平滑性がすぐれたものとなる。
(ロ) 成形に先立つて空気その他の無機ガス中に加
圧下に保存して無機ガスを予備発泡粒子中に導
入するいわゆる加圧熟成工程においてガスが粒
子中に導入され易く、したがつて熟成に要する
時間を短縮することができる。
次に実施例および比較例を示して本発明を説明
する。
実施例・比較例
エチレン−プロピレン共重合体として下記のも
のを用い、第１表に示す配合および条件で予備発
泡粒子を製造した。
Ａ：エチレン成分含有量が2.5重量％のエチレン
−プロピレンランダム共重合体
Ｂ：エチレン成分含有量が15重量％のエチレン−
プロピレンブロツク共重合体
但し第１表におけるシリカは、あらかじめ上記
樹脂に均一に混合されたものである。また比較例
で用いた樹脂はフイルム・シート製造用に市販さ
れているものである。
なお分散媒としては水300重量部を用い、また
すべての例において酸化アルミニウム0.3重量部
を分散剤として用いた。発泡剤はフレオン−12で
ある。
得られた予備発泡粒子の性状を第１表に併せて
示す。
次にこの予備発泡粒子を常温・常圧下で50時間
熟成し、更に20℃・４Kg／cm2(G)の空気により100
時間加圧熟成を行なつたのち厚さ50mm、長さ300
mm、幅300mmのキヤビテイを持つ金型に充填し、
樹脂Ａの場合は3.2Kg／cm2(G)、樹脂Ｂの場合は5.3
Kg／cm2(G)の水蒸気により加熱して成形した。得ら
れた発泡成形体の性状を第２表に示す。
なお「柔軟性試験」はNDS Z0503により行な
つた結果を示す。また「収縮率」は、成形後60℃
で24時間養生した後の発泡成形体の寸法の金型寸
法に対する比率（％）を示す。
The present invention relates to a method for producing pre-expanded ethylene-propylene copolymer particles. Foamed molded products made of ethylene-propylene copolymer are softer and more pliable than foamed molded products made of polystyrene resin, and have excellent low-temperature properties and chemical resistance, so they have recently been replaced by polystyrene-based products. It has come to be used in many fields. However, a drawback not limited to this copolymer but common to polyolefin resins is that foam molding is somewhat more difficult than in the case of polystyrene resins, making it difficult to fully demonstrate its excellent properties. points are pointed out. For example, one of the advantageous manufacturing methods for foamed molded products is the method using pre-expanded particles according to the invention of Japanese Patent Publication No. 56-1344, in which resin particles are made to absorb a volatile solvent-based foaming agent, and then sealed together with a dispersion medium. The pre-expanded particles obtained by heating under pressure in a container and then releasing them together with a dispersion medium into an atmosphere at a lower pressure than the inside of the container to cause foaming are then filled into a mold, and then heated by means such as steam injection. There is a method of molding by heating to re-foam and fuse the foamed particles to each other, but if a foamed molded product of ethylene-propylene copolymer is produced by this method, there will be a large shrinkage during molding, so it will be difficult to obtain The molded product does not exhibit the flexibility expected from the expansion ratio, and other physical properties are also not satisfactory. As a result of various studies on the molding difficulty of ethylene-propylene copolymers as described above, the present inventors discovered that the cause of the difficulty lies in the fine air bubbles peculiar to the pre-expanded particles of ethylene-propylene copolymers. Ivy. As a result of further research, it was discovered that the reason why the cell diameter becomes smaller in the case of ethylene-propylene copolymer is not necessarily due to the inherent properties of ethylene-propylene copolymer, but rather because it is commonly added to this copolymer. I learned that this is caused by inorganic additives, especially silica. The present invention was completed based on the above findings, and consists of absorbing a volatile solvent-based blowing agent into ethylene-propylene copolymer particles with a silica content of less than 0.1%, and softening the particles together with a dispersion medium in a closed container. Provided is a method for producing pre-expanded ethylene-propylene copolymer particles having coarse bubbles, the method comprising heating the pre-expanded particles to a temperature higher than that temperature, and then releasing the pre-expanded particles together with a dispersion medium into an atmosphere at a lower pressure than in the container to cause foaming. It is something to do. Here, "pre-expanded ethylene-propylene copolymer particles with coarse cells" are those whose expansion ratio is 3 times or more and whose average number of cells is 150 cells/mm2 or less when observed on a cut surface passing through the center of the particles. It seems like there is
Pre-expanded ethylene-propylene copolymer particles having relatively large diameter cells. These pre-expanded particles have a higher density compared to the aforementioned pre-expanded ethylene-propylene copolymer particles having fine cells (the average number of cells exceeds 150 cells/mm 2 and is usually 300 cells/mm 2 or more). Provides a foam molded product with excellent properties in many respects. The ethylene-propylene copolymer used in the present invention may be a random copolymer or a block copolymer, or may be a crosslinked product thereof. However, particularly preferred ethylene-propylene copolymers have a copolymerization ratio of ethylene component of 10.
% by weight or less and is non-crosslinked. And the silica content must be less than 0.1%.
If the silica content is 0.1% or more, it is not possible to obtain a material having small bubbles. Silica
A content of 0.05% or less is particularly preferred because it easily provides a cell count of 100 cells/mm 2 or less. The method of the present invention is not essentially different from the method for producing pre-expanded particles described in Japanese Patent Publication No. 56-1344, except that the raw material resin is limited as described above. The outline is explained below. The volatile solvent-based blowing agent to be absorbed into the ethylene-propylene copolymer is an organic compound with a low boiling point that can permeate the ethylene-propylene copolymer particles (usually having a boiling point of about -50 to 110°C). is appropriate. Specific examples include: aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane;
Cycloaliphatic hydrocarbons such as cyclobutane and cyclopentane; halogenated hydrocarbons such as trichlorofluoromethane, dichlorofluoromethane, dichlorodifluoromethane, dichlorotetrafluoroethane, methyl chloride, ethyl chloride, and methylene chloride. In order to absorb the blowing agent into the ethylene-propylene copolymer particles, the two may be brought into contact at room temperature or under heating, but this step can be carried out independently or by placing the resin particles together with the dispersion medium in a closed container. It may be performed simultaneously with the heating step. In that case, untreated resin particles, a blowing agent, and a dispersion medium are placed in a closed container, and the temperature is raised while stirring. Alternatively, heat the untreated resin particles and dispersion medium in a closed container,
A blowing agent is injected into a closed container and mixed at any stage until a predetermined temperature is reached. As the dispersion medium, water can be used as well as organic solvents that do not dissolve the ethylene-propylene copolymer, such as ethylene glycol, glycerin, methanol, and ethanol. When dispersing resin particles in a dispersion medium and heating it in a closed container, the dispersion medium also contains fine powders of dispersants such as aluminum oxide, titanium oxide, basic magnesium carbonate, basic zinc carbonate, calcium carbonate, etc. It may be added to prevent fusion of resin particles. The amount of the dispersant added is preferably about 0.01 to 10 parts by weight per 100 parts by weight of the resin particles. The heating temperature in the heating step may be any temperature that is higher than the softening temperature of the resin and does not cause fusion between resin particles. The preferred temperature naturally varies depending on the type of ethylene-propylene copolymer, but is usually 90 to 170°C. If this temperature is too high, not only will it be difficult to proceed to the next foaming step due to fusion of the particles, but also the bubbles will be destroyed, resulting in foamed particles with a low closed cell ratio. Although the heating time is not particularly limited, it goes without saying that if the blowing agent is to be absorbed during this heating, the treatment must be carried out until the blowing agent is uniformly absorbed into the particles. Thereafter, the resin particles are foamed by releasing the contents of the sealed container into an atmosphere having a pressure lower than the internal pressure of the container to vaporize the foaming agent. When water is used as a dispersion medium, the atmosphere in which foaming is carried out as described above may generally be atmospheric pressure. According to the method of the present invention as described above, it is possible to easily produce pre-expanded ethylene-propylene copolymer particles with coarse bubbles having an apparent expansion ratio of 3 to 60 times and an average number of cells of 150 cells/mm 2 or less. can be manufactured. These ethylene-propylene copolymer pre-expanded particles can be molded in a mold in exactly the same manner as conventional pre-expanded particles, and due to the coarseness of the cells, they have the following advantageous properties: shows. (a) Since there is little shrinkage and therefore the particles are reliably fused, the resulting foamed molded product has excellent physical properties and surface smoothness. (b) In the so-called pressure ripening process, in which the particles are stored under pressure in air or other inorganic gas and the inorganic gas is introduced into the pre-expanded particles prior to molding, gas is easily introduced into the particles, and therefore the particles are not ripened. The time required can be shortened. Next, the present invention will be explained by showing examples and comparative examples. Examples/Comparative Examples Pre-expanded particles were produced using the following ethylene-propylene copolymers under the formulation and conditions shown in Table 1. A: Ethylene-propylene random copolymer with an ethylene content of 2.5% by weight B: Ethylene-propylene with an ethylene content of 15% by weight
Propylene block copolymer However, the silica in Table 1 was uniformly mixed with the above resin in advance. Further, the resin used in the comparative example is one that is commercially available for producing films and sheets. Note that 300 parts by weight of water was used as a dispersion medium, and 0.3 parts by weight of aluminum oxide was used as a dispersant in all examples. The blowing agent is Freon-12. The properties of the obtained pre-expanded particles are also shown in Table 1. Next, these pre-expanded particles were aged for 50 hours at room temperature and pressure, and then aged for 100 hours at 20℃ and 4Kg/cm 2 (G) of air.
After being aged under pressure for hours, the thickness is 50mm and the length is 30mm.
Fill a mold with a cavity of 300mm wide and 300mm wide.
3.2Kg/cm 2 (G) for resin A, 5.3 for resin B
It was molded by heating with water vapor of Kg/cm 2 (G). Table 2 shows the properties of the foamed molded product obtained. The "flexibility test" shows the results conducted using NDS Z0503. In addition, the "shrinkage rate" is 60℃ after molding.
The ratio (%) of the dimensions of the foam molded product to the mold dimensions after curing for 24 hours is shown.
【表】【table】
【表】【table】
Claims (1)
プロピレン共重合体粒子に揮発性溶剤型発泡剤を
吸収させて分散媒と共に密閉容器中で軟化温度以
上の温度に加熱し、次いでこれを分散媒と共に容
器内よりも低圧の雰囲気に放出して発泡させるこ
とを特徴とする粗大気泡を有するエチレン−プロ
ピレン共重合体予備発泡粒子の製造法。1 Ethylene with a silica content of less than 0.1%
A volatile solvent-based blowing agent is absorbed into propylene copolymer particles and heated to a temperature above the softening temperature in a closed container together with a dispersion medium, and then released together with the dispersion medium into an atmosphere at a lower pressure than the inside of the container to form foam. 1. A method for producing pre-expanded ethylene-propylene copolymer particles having coarse cells.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9309982A JPS58210933A (en) | 1982-06-02 | 1982-06-02 | Preparation of pre-expanded granule of ethylene-propylene copolymer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9309982A JPS58210933A (en) | 1982-06-02 | 1982-06-02 | Preparation of pre-expanded granule of ethylene-propylene copolymer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58210933A JPS58210933A (en) | 1983-12-08 |
| JPS6324616B2 true JPS6324616B2 (en) | 1988-05-21 |
Family
ID=14073069
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9309982A Granted JPS58210933A (en) | 1982-06-02 | 1982-06-02 | Preparation of pre-expanded granule of ethylene-propylene copolymer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58210933A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS614738A (en) * | 1984-06-19 | 1986-01-10 | Japan Styrene Paper Co Ltd | Preparation of foamed polypropylene resin particle |
| US20160319095A1 (en) | 2013-12-27 | 2016-11-03 | Kaneka Corporation | Polyolefin resin foam particles, and polyolefin resin in-mold expansion molded article |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58199125A (en) * | 1982-05-14 | 1983-11-19 | Kanegafuchi Chem Ind Co Ltd | Prefoaming of expandable thermoplastic resin particles |
-
1982
- 1982-06-02 JP JP9309982A patent/JPS58210933A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58199125A (en) * | 1982-05-14 | 1983-11-19 | Kanegafuchi Chem Ind Co Ltd | Prefoaming of expandable thermoplastic resin particles |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58210933A (en) | 1983-12-08 |
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