JPS639975B2 - - Google Patents
Info
- Publication number
- JPS639975B2 JPS639975B2 JP58132552A JP13255283A JPS639975B2 JP S639975 B2 JPS639975 B2 JP S639975B2 JP 58132552 A JP58132552 A JP 58132552A JP 13255283 A JP13255283 A JP 13255283A JP S639975 B2 JPS639975 B2 JP S639975B2
- Authority
- JP
- Japan
- Prior art keywords
- internal pressure
- expanded particles
- pressure
- container
- particles
- 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 64
- 238000000034 method Methods 0.000 claims description 9
- 238000001816 cooling Methods 0.000 claims description 4
- 238000011282 treatment Methods 0.000 description 19
- 238000000465 moulding Methods 0.000 description 10
- 239000007789 gas Substances 0.000 description 7
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- 229910001872 inorganic gas Inorganic materials 0.000 description 6
- 238000010583 slow cooling Methods 0.000 description 6
- 230000003247 decreasing effect Effects 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000004604 Blowing Agent Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting 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
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- RGSFGYAAUTVSQA-UHFFFAOYSA-N Cyclopentane Chemical compound C1CCCC1 RGSFGYAAUTVSQA-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
- 210000002421 cell wall Anatomy 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 230000004927 fusion Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 230000037303 wrinkles Effects 0.000 description 2
- LVGUZGTVOIAKKC-UHFFFAOYSA-N 1,1,1,2-tetrafluoroethane Chemical compound FCC(F)(F)F LVGUZGTVOIAKKC-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
- 239000004677 Nylon Substances 0.000 description 1
- -1 Polypropylene Polymers 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 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
- 229920003020 cross-linked polyethylene Polymers 0.000 description 1
- 239000004703 cross-linked polyethylene Substances 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- PXBRQCKWGAHEHS-UHFFFAOYSA-N dichlorodifluoromethane Chemical compound FC(F)(Cl)Cl PXBRQCKWGAHEHS-UHFFFAOYSA-N 0.000 description 1
- 235000019404 dichlorodifluoromethane Nutrition 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 229960003750 ethyl chloride Drugs 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 150000008282 halocarbons Chemical class 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 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
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229940073584 methylene chloride Drugs 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- 229910052754 neon Inorganic materials 0.000 description 1
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920005672 polyolefin resin Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920005629 polypropylene homopolymer Polymers 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 230000001502 supplementing effect Effects 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
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/34—Auxiliary operations
- B29C44/3461—Making or treating expandable particles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2067/00—Use of polyesters or derivatives thereof, as moulding material
Landscapes
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
Description
本発明は予備発泡粒子の加圧処理方法に関す
る。
一般に、予備発泡粒子を金型に充填し型内成型
を行なうに当り、該粒子に成型に適した内圧を付
与するため成型工程前に加圧処理を行なうことは
知られている。通常、加圧処理は加圧容器内に前
記粒子を入れ且つ該容器内に空気、窒素等の無機
ガスを供給して加圧し、前記粒子内に無機ガスを
浸透圧入して一定のガス圧力を付与するものであ
る。
従来の加圧処理方法は、予備発泡粒子をある一
定の圧力雰囲気下で、ある一定時間加圧すること
によつて行なわれている。また、前記粒子を８
Kg／cm2(G)以下の圧力雰囲気下に保持した後、0.5
〜３Kg／cm2(G)の範囲であつて前記圧力よりも低い
圧力雰囲気下に保持する２段階加圧処理方法も知
られている（特公昭52−30304号）。
しかしながら、従来方法はいずれも前記粒子を
加圧容器内に入れた後、急激に加圧し、所定の高
い圧力に保持するものであるため、粒子は高い加
圧圧力の影響を受けて著しく収縮して該粒子の気
泡壁が破壊され、この結果粒子の物理的強度の低
下や粒子表面にシワ、傷等を生じる欠点がある。
また粒子が収縮すると粒子内気泡の体積が減少し
て粒子内圧が増大するため、該内圧と加圧雰囲気
圧との間における圧力差が小さくなり、そのた
め、加圧気体が粒子内に浸透圧入され難くなり、
その結果、加圧雰囲気が除去されて元の体積に回
復したときの予備発泡粒子の内圧を成型に必要な
値まで高めることができないという欠点がある。
このため従来の方法により加圧処理を行なつた予
備発泡粒子を用いて成型を行なつても、得られた
成型品に収縮、ヒケ現象が起こつたり、融着不良
を生じたりして、良好な発泡成型体を得ることが
できなかつた。
本発明者らは上記の点に鑑み鋭意研究した結
果、予備発泡粒子を収縮させることなく加圧が行
なえ、該予備発泡粒子に短時間で成型に必要な内
圧を付与することができる加圧処理方法を見い出
し本発明を完成するに至つた。
即ち本発明は予備発泡粒子を密閉容器内に入
れ、該容器内圧を予備発泡粒子内圧と略同一圧に
調整した後、予備発泡粒子に融着、収縮を生じさ
せない温度まで、密閉状態で徐々に昇温して容器
内圧を上昇せしめ、しかる後、高められた容器内
圧を維持した状態で徐冷することを特徴とする予
備発泡粒子の加圧処理方法を要旨とする。
本発明は、いかなる種類の予備発泡粒子にも適
用し得るが、ポリプロピレン単独重合体、エチレ
ン―プロピレン共重合体、エチレン―酢酸ビニル
共重合体、エチレン―ブテン共重合体等のポリオ
レフイン系樹脂を基材とする予備発泡粒子あるい
はナイロン、ポリエステル系エラストマーを基材
とする予備発泡粒子等圧力により収縮を生じやす
い予備発泡粒子の加圧処理に特に好適である。
本発明においてはまず予備発泡粒子を密閉容器
内に入れ、容器内圧を予備発泡粒子内圧と略同一
圧に調整する。容器内圧の調整は例えば空気、窒
素、アルゴン、ヘリウム、ネオン、二酸化炭素等
の無機ガスまたは上記無機ガスと揮発性発泡剤と
の混合ガスが用いられる。揮発性発泡剤として
は、例えばプロパン、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あ
るいは、トリクロロフロロメタン、ジクロロジフ
ロロメタン、ジクロロテトラフロロエタン、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が挙げられる。
上記無機ガスあるいは無機ガスと揮発性発泡剤
との混合ガス（通常は空気を用いることが経済的
にも好ましい。）により容器内圧力を予備発泡粒
子の内圧〜該内圧＋0.5Kg／cm2の圧力に調整する
ことが好ましい。
上記容器内圧の調整を行なつた後、予備発泡粒
子に融着、収縮を生じさせない温度まで密閉状態
で徐々に昇温する。この昇温終了時の温度は基材
樹脂の種類等によつても異なるが通常50℃〜130
℃であり、また昇温速度は0.5℃／分〜５℃／分
が好ましい。このときの容器内圧：P2（atm）は、
昇温前の温度をT1(K)、容器内圧をP1（atm）と
し、昇温終了時の温度をT2(K)とすると、
P2＝T2／T1・P1
で与えられる圧力まで昇圧せしめられる。
次に本発明においては上記高められた容器内
圧：P2を維持した状態で予備発泡粒子を徐冷す
すが、このとき、温度低下に伴なう容器内圧の減
少分を容器内に前述の無機ガスあるいは無気ガス
と揮発性発泡剤との混合ガスを供給して補うこと
により徐冷終了まで容器内圧をP2に維持する。
上記徐冷工程における降温速度は0.01℃／分〜２
℃／分が好ましい。予備発泡粒子を室温まで徐冷
した後、容器内圧を常圧まで降下させて得た予備
発泡粒子は、元の予備発泡粒子の内圧の1.2倍〜
1.6倍程度の内圧を有する。また上記加圧処理に
要する時間は通常２時間〜24時間程度である。
本発明において上記徐冷は一定の降温速度で行
なつてもよく、また降温につれて段階的に降温速
度を変化させて行なつてもよい。また本発明にお
ける加圧処理は１回に限らず、複数回繰り返して
行なつてもよい。
以上説明したように本発明の加圧処理方法は予
備発泡粒子に収縮を生じさせないよう加圧処理し
て、粒子に成型に必要な内圧を付与するものであ
るから、加圧処理後の予備発泡粒子は、気泡壁破
壊による物性低下や、粒子表面にシワ、傷等を生
じる虞れはない。また加圧処理により粒子が収縮
しない結果、粒子に成型に必要な内圧を確実かつ
短時間で付与することができる。しかして本発明
により加圧処理を行なつた予備発泡粒子を成型用
型に充填して加熱発泡せしめることにより、粒子
の融着性に優れ、収縮、ヒケ現象の生じることが
ない等優れた成型体を得ることができる。
以下実施例、比較例を挙げて本発明を更に詳細
に説明する。尚、圧力は特に明記しない場合は絶
対圧を示す。
実施例 １
20℃（室温）において内圧1.6Kg／cm2の発泡倍
率20倍のポリプロピレン予備発泡粒子（融点148
℃）800ｇを20のオートクレーブに入れて密閉
し、オートクレーブ内圧を空気にて1.6Kg／cm2に
調整した後、密閉状態を維持して１℃／分の昇温
速度で127℃（400K）まで昇温した。この時のオ
ートクレーブ内圧は2.18Kg／cm2であつた。オート
クレーブのガラス窓より予備発泡粒子の状態を観
察した結果、予備発泡粒子に収縮は認められなか
つた。次にオートクレーブ内に空気を供給してオ
ートクレーブ内圧を2.18Kg／cm2に保持しつつ127
℃〜77℃までは１℃／分、77℃〜52℃までは0.3
℃／分、52℃〜20℃（室温）までは0.1℃／分の
降温速度で徐冷を行なつた。上記徐冷終了までの
間予備発泡粒子に収縮は認められなかつた。上記
加圧処理に要した時間は10時間であつた。処理後
の予備発泡粒子の表面状態、内圧を測定した。結
果を第１表に示す。また上記予備発泡粒子を30mm
×300mm×300mm（内径）の金型に充填し、3.5
Kg／cm2(G)の水蒸気により加熱して成型を行なつ
た。得られた成型体を50℃のオーブン内で20時間
乾燥後、成型体の収縮率を測定した。結果を第１
表にあわせて示す。
比較例 １
実施例１と同一の予備発泡粒子をオートクレー
ブ内に入れ、室温（20℃）で空気により10Kg／cm2
にオートクレーブ内圧を調整して20時間加圧処理
を行なつた。処理後の予備発泡粒子の表面状態、
内圧を測定した。結果を第１表に示す。また上記
予備発泡粒子を実施例１と同様にして成型した。
得られた成型体の収縮率を測定した結果を第１表
に示す。
実施例 ２
ゲル分率60％の架橋ポリエチレンからなる発泡
倍率20倍、22℃（室温）において内圧1.24Kg／cm2
を有する予備発泡粒子800ｇを20のオートクレ
ーブに入れ、密閉してオートクレーブ内圧を空気
にて1.24Kg／cm2に調整した。次いで密閉状態で１
℃／分の速度で97℃（370K）まで昇温した。こ
の時のオートクレーブ内圧は、1.56Kg／cm2であつ
た。またオートクレーブのガラス窓より予備発泡
粒子の状態を観察した結果、該粒子に収縮は認め
られなかつた。次にオートクレーブ内に空気を供
給してオートクレーブ内圧を、1.56Kg／cm2に保持
しつつ一定の降温速度で８時間かけて室温まで徐
冷した。この予備発泡粒子は22℃（室温）におい
て1.56Kg／cm2の内圧を有していた。更にこの予備
発泡粒子をオートクレーブに入れたままオートク
レーブを再び密閉し、オートクレーブ内圧を空気
にて1.56Kg／cm2に調整した後、上記と同様の昇
温、徐冷を行なつた（97℃に昇温したときのオー
トクレーブ内圧は1.94Kg／cm2であり、徐冷時には
空気にてオートクレーブ内圧を1.94Kg／cm2に保持
した。）２回の加圧処理に要した時間は18時間で
あつた。上記２回の加圧処理を行なつた後の予備
発泡粒子の表面状態、および内圧を測定した。結
果を第１表に示す。また上記予備発泡粒子を実施
例１と同様にして成型を行ない（但し、2.5Kg／
cm2(G)の水蒸気により加熱した。）得られた成型体
の収縮率を測定した。結果を第１表にあわせて示
す。
比較例 ２
実施例２と同一の予備発泡粒子をオートクレー
ブに入れ、室温（22℃）でオートクレーブ内圧を
空気により３Kg／cm2に調整して32時間加圧処理を
行なつた。処理後の予備発泡粒子の表面状態、お
よび内圧を測定した。結果を第１表に示す。また
この予備発泡粒子を用いて実施例２と同様にして
成型して得た成型体の収縮率を測定した。結果を
第１表に示す。
The present invention relates to a method for pressurizing pre-expanded particles. It is generally known that when pre-expanded particles are filled into a mold and molded in the mold, pressure treatment is performed before the molding process in order to apply an internal pressure suitable for molding to the particles. Usually, in pressurization treatment, the particles are placed in a pressurized container, and an inorganic gas such as air or nitrogen is supplied into the container to increase the pressure, and the inorganic gas is osmoticly injected into the particles to maintain a constant gas pressure. It is something that is given. Conventional pressure treatment methods are carried out by pressurizing pre-expanded particles under a certain pressure atmosphere for a certain period of time. In addition, the particles were added to 8
Kg/cm 2 (G) or less after being maintained in a pressure atmosphere of 0.5
A two-step pressure treatment method is also known in which the pressure is maintained in a pressure atmosphere in the range of ~3 Kg/cm 2 (G) and lower than the above pressure (Japanese Patent Publication No. 30304/1983). However, in all conventional methods, after the particles are placed in a pressurized container, they are rapidly pressurized and held at a predetermined high pressure, so the particles shrink significantly under the influence of the high pressurizing pressure. The cell walls of the particles are destroyed, resulting in a disadvantage that the physical strength of the particles decreases and wrinkles, scratches, etc. occur on the particle surfaces.
Furthermore, when particles contract, the volume of intraparticle air bubbles decreases and the internal pressure of the particles increases, so the pressure difference between the internal pressure and the pressurized atmospheric pressure becomes smaller, so that pressurized gas is osmotically injected into the particles. It becomes difficult,
As a result, there is a drawback that the internal pressure of the pre-expanded particles cannot be increased to a value necessary for molding when the pressurized atmosphere is removed and the original volume is restored.
For this reason, even when molding is performed using pre-expanded particles that have been subjected to pressure treatment using the conventional method, shrinkage, sink marks, or poor fusion may occur in the resulting molded product. It was not possible to obtain a good foam molded product. The inventors of the present invention have conducted extensive research in view of the above points, and have found that pressurization can be performed without shrinking the pre-expanded particles, and that the internal pressure necessary for molding can be applied to the pre-expanded particles in a short time. They found a method and completed the present invention. That is, in the present invention, pre-expanded particles are placed in a closed container, and after adjusting the internal pressure of the container to approximately the same pressure as the internal pressure of the pre-expanded particles, the pre-expanded particles are gradually heated in a closed state to a temperature that does not cause melting or shrinkage of the pre-expanded particles. The gist of the present invention is a method for pressurizing pre-expanded particles, which is characterized by raising the temperature to increase the internal pressure of the container, and then gradually cooling while maintaining the increased internal pressure of the container. The present invention is applicable to any type of pre-expanded particles, but is based on polyolefin resins such as polypropylene homopolymers, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ethylene-butene copolymers, etc. It is particularly suitable for pressure treatment of pre-expanded particles that tend to shrink due to pressure, such as pre-expanded particles made of nylon or polyester elastomer as a base material. In the present invention, first, the pre-expanded particles are placed in a closed container, and the internal pressure of the container is adjusted to approximately the same pressure as the internal pressure of the pre-expanded particles. To adjust the internal pressure of the container, for example, an inorganic gas such as air, nitrogen, argon, helium, neon, carbon dioxide, or a mixed gas of the above-mentioned inorganic gas and a volatile blowing agent is used. Examples of volatile blowing agents include aliphatic hydrocarbons such as propane, butane, pentane, hexane, and heptane, cycloaliphatic hydrocarbons such as cyclobutane and cyclopentane, or trichlorofluoromethane, dichlorodifluoromethane, and dichloromethane. Examples include halogenated hydrocarbons such as tetrafluoroethane, methyl chloride, ethyl chloride, and methylene chloride. The pressure inside the container is adjusted from the internal pressure of the pre-expanded particles to the internal pressure + 0.5 kg/cm 2 using the above inorganic gas or a mixed gas of an inorganic gas and a volatile blowing agent (usually, it is economically preferable to use air). Preferably, the pressure is adjusted. After adjusting the internal pressure of the container, the temperature is gradually raised in a closed state to a temperature that does not cause melting or shrinkage of the pre-expanded particles. The temperature at the end of this heating process varies depending on the type of base resin, etc., but is usually 50℃ to 130℃.
The heating rate is preferably 0.5°C/min to 5°C/min. The internal pressure of the container at this time: P 2 (atm) is
If the temperature before heating is T 1 (K), the internal pressure of the container is P 1 (atm), and the temperature at the end of heating is T 2 (K), then P 2 = T 2 /T 1・P 1 is given. The pressure is increased to the pressure that is reached. Next, in the present invention, the pre-expanded particles are slowly cooled while maintaining the increased container internal pressure: P 2. At this time, the decrease in the container internal pressure due to the temperature drop is absorbed into the container by the above-mentioned inorganic material. By supplying and supplementing gas or a mixed gas of an airless gas and a volatile blowing agent, the internal pressure of the container is maintained at P 2 until the slow cooling is completed.
The temperature decreasing rate in the above slow cooling process is 0.01℃/min ~ 2
C/min is preferred. After slowly cooling the pre-expanded particles to room temperature, the internal pressure of the container is lowered to normal pressure.
It has an internal pressure of about 1.6 times. Further, the time required for the above-mentioned pressure treatment is usually about 2 hours to 24 hours. In the present invention, the above-mentioned slow cooling may be performed at a constant temperature decreasing rate, or may be performed by changing the temperature decreasing rate in stages as the temperature decreases. Further, the pressure treatment in the present invention is not limited to one time, but may be repeated multiple times. As explained above, the pressure treatment method of the present invention applies pressure treatment to the pre-expanded particles so as not to cause shrinkage, and gives the particles the internal pressure necessary for molding. There is no possibility that the particles will deteriorate in physical properties due to cell wall destruction or that wrinkles, scratches, etc. will occur on the particle surface. Further, since the particles do not shrink due to the pressure treatment, the internal pressure necessary for molding can be applied to the particles reliably and in a short time. However, by filling a mold with pre-expanded particles that have been subjected to pressure treatment according to the present invention and heating and foaming them, excellent molding can be achieved, such as excellent particle fusion properties and no shrinkage or sink phenomenon. You can get a body. The present invention will be explained in more detail below by giving Examples and Comparative Examples. It should be noted that pressure indicates absolute pressure unless otherwise specified. Example 1 Polypropylene pre - expanded particles (melting point 148
℃) 800g was placed in a 20 degree autoclave and sealed, and the internal pressure of the autoclave was adjusted to 1.6Kg/ cm2 with air.Then, the airtight condition was maintained and the temperature was raised to 127℃ (400K) at a temperature increase rate of 1℃/min. The temperature rose. The internal pressure of the autoclave at this time was 2.18 Kg/cm 2 . As a result of observing the state of the pre-expanded particles through the glass window of the autoclave, no shrinkage was observed in the pre-expanded particles. Next, air was supplied into the autoclave to maintain the autoclave internal pressure at 2.18Kg/ cm2 .
1℃/min from ℃ to 77℃, 0.3 from 77℃ to 52℃
°C/min, and slow cooling was performed at a temperature decreasing rate of 0.1 °C/min from 52 °C to 20 °C (room temperature). No shrinkage was observed in the pre-expanded particles until the end of the slow cooling. The time required for the above pressure treatment was 10 hours. The surface condition and internal pressure of the pre-expanded particles after treatment were measured. The results are shown in Table 1. In addition, the above pre-expanded particles were added to 30mm
Fill a mold with ×300mm×300mm (inner diameter) and 3.5
Molding was carried out by heating with water vapor of Kg/cm 2 (G). After drying the obtained molded product in an oven at 50° C. for 20 hours, the shrinkage rate of the molded product was measured. Results first
Also shown in the table. Comparative Example 1 The same pre-expanded particles as in Example 1 were placed in an autoclave and heated to 10 kg/cm 2 with air at room temperature (20°C).
The internal pressure of the autoclave was adjusted to perform pressure treatment for 20 hours. Surface condition of pre-expanded particles after treatment,
The internal pressure was measured. The results are shown in Table 1. Further, the pre-expanded particles were molded in the same manner as in Example 1.
Table 1 shows the results of measuring the shrinkage rate of the molded product obtained. Example 2 Made of cross-linked polyethylene with a gel fraction of 60%, expansion ratio 20 times, internal pressure 1.24 Kg/cm 2 at 22°C (room temperature)
800 g of pre-expanded particles having the following properties were placed in a 20 autoclave, the autoclave was sealed, and the internal pressure of the autoclave was adjusted to 1.24 Kg/cm 2 with air. Then 1 in a closed state
The temperature was increased to 97°C (370K) at a rate of °C/min. The internal pressure of the autoclave at this time was 1.56 Kg/cm 2 . Further, as a result of observing the state of the pre-expanded particles through the glass window of the autoclave, no shrinkage was observed in the particles. Next, air was supplied into the autoclave to maintain the autoclave internal pressure at 1.56 Kg/cm 2 while slowly cooling the autoclave to room temperature over 8 hours at a constant temperature decreasing rate. The pre-expanded particles had an internal pressure of 1.56 Kg/cm 2 at 22°C (room temperature). Furthermore, the autoclave was sealed again while the pre-expanded particles were still in the autoclave, and the internal pressure of the autoclave was adjusted to 1.56 Kg/ cm2 with air, and then the temperature was raised and slowly cooled in the same manner as above (to 97°C). The internal pressure of the autoclave was 1.94 Kg/cm 2 when the temperature was raised, and the internal pressure of the autoclave was maintained at 1.94 Kg/cm 2 with air during slow cooling.) The time required for the two pressurization treatments was 18 hours. Ta. The surface condition and internal pressure of the pre-expanded particles after the two pressurization treatments were measured. The results are shown in Table 1. Further, the above pre-expanded particles were molded in the same manner as in Example 1 (however, 2.5 kg/
Heated with cm 2 (G) of water vapor. ) The shrinkage rate of the obtained molded body was measured. The results are also shown in Table 1. Comparative Example 2 The same pre-expanded particles as in Example 2 were placed in an autoclave, and pressurized for 32 hours at room temperature (22°C) with the autoclave internal pressure adjusted to 3 kg/cm 2 with air. The surface condition and internal pressure of the pre-expanded particles after treatment were measured. The results are shown in Table 1. Further, the shrinkage rate of a molded product obtained by molding the pre-expanded particles in the same manner as in Example 2 was measured. The results are shown in Table 1.
【表】【table】
【表】【table】
Claims (1)
圧を予備発泡粒子内圧と略同一圧に調整した後、
予備発泡粒子に融着、収縮を生じさせない温度ま
で、密閉状態で徐々に昇温して容器内圧を上昇せ
しめ、しかる後、高められた容器内圧を維持した
状態で徐冷することを特徴とする予備発泡粒子の
加圧処理方法。1. After putting the pre-expanded particles into a closed container and adjusting the internal pressure of the container to approximately the same pressure as the internal pressure of the pre-expanded particles,
It is characterized by gradually increasing the temperature in a closed state to a temperature that does not cause the pre-expanded particles to fuse or shrink, thereby increasing the internal pressure of the container, and then slowly cooling while maintaining the increased internal pressure of the container. A method for pressurizing pre-expanded particles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58132552A JPS6024933A (en) | 1983-07-20 | 1983-07-20 | Pressurizing treatment of pre-expanded particle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58132552A JPS6024933A (en) | 1983-07-20 | 1983-07-20 | Pressurizing treatment of pre-expanded particle |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6024933A JPS6024933A (en) | 1985-02-07 |
| JPS639975B2 true JPS639975B2 (en) | 1988-03-03 |
Family
ID=15083953
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58132552A Granted JPS6024933A (en) | 1983-07-20 | 1983-07-20 | Pressurizing treatment of pre-expanded particle |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6024933A (en) |
-
1983
- 1983-07-20 JP JP58132552A patent/JPS6024933A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6024933A (en) | 1985-02-07 |
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