JPH0333492B2 - - Google Patents
Info
- Publication number
- JPH0333492B2 JPH0333492B2 JP57160517A JP16051782A JPH0333492B2 JP H0333492 B2 JPH0333492 B2 JP H0333492B2 JP 57160517 A JP57160517 A JP 57160517A JP 16051782 A JP16051782 A JP 16051782A JP H0333492 B2 JPH0333492 B2 JP H0333492B2
- Authority
- JP
- Japan
- Prior art keywords
- mold
- molten resin
- sheet
- molded product
- molding
- 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 - Lifetime
Links
- 238000000465 moulding Methods 0.000 claims description 12
- 229920005992 thermoplastic resin Polymers 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 2
- 229920005989 resin Polymers 0.000 description 25
- 239000011347 resin Substances 0.000 description 25
- 229920005629 polypropylene homopolymer Polymers 0.000 description 3
- 230000037303 wrinkles Effects 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 238000003825 pressing Methods 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
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C45/14778—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles the article consisting of a material with particular properties, e.g. porous, brittle
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Laminated Bodies (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Description
【発明の詳細な説明】
本発明は熱可塑性樹脂のプレス成形に関するも
のである。熱可塑性樹脂（以下樹脂という）を押
出機などで溶融可塑化し、これをプレス用雌雄金
型間に供給し、プレスで加圧冷却して得た成形品
は射出成形品に較べ、金型にゲートを設ける必要
がなく、プレス中に溶融樹脂が金型内を一様に流
れるため、樹脂の配向が少ないこと、成形品にゲ
ート近傍の弱点部がなく、ウエルド部もない（又
は少なく出来る）ため、物性面でよい成形品が得
られるばかりでなく配向や、残留歪がないため、
成形品にねじれ、変形などのトラブルのない成形
品が得られる。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to press molding of thermoplastic resin. Molded products obtained by melting and plasticizing thermoplastic resin (hereinafter referred to as resin) using an extruder, supplying it between male and female press molds, and cooling it under pressure in the press are faster than injection molded products. There is no need to provide a gate, and the molten resin flows uniformly within the mold during pressing, so there is little orientation of the resin, there is no weak point near the gate in the molded product, and there is no weld (or can be reduced). Therefore, not only can molded products with good physical properties be obtained, but there is no orientation or residual strain, so
Molded products can be obtained without problems such as twisting and deformation.
しかしながらこの方法で成形する場合、金型面
に置かれた溶融樹脂は、プレス圧力により流動し
金型キヤビテイの隅々まで充満し、成形品となる
が、かくして得られる成形品の最初に溶融樹脂が
金型に接した部分は他の部分に較べ、著しく光沢
が悪くなつたり、小さなシワが発生するなどのト
ラブル（以下にコールドマークと呼ぶ）が生じ、
外観の良好なる成形品を得ることが出来ない。 However, when molding with this method, the molten resin placed on the mold surface flows due to the press pressure and fills every corner of the mold cavity, forming a molded product. The parts that come into contact with the mold are noticeably less glossy than other parts, and problems such as small wrinkles (hereinafter referred to as cold marks) occur.
It is not possible to obtain a molded product with a good appearance.
この様なコールドマークが発生するのは、溶融
樹脂が金型面に置かれてから、プレス圧力が作用
して溶融樹脂が金型内を流動し始めるまでの間、
金型面に置かれた溶融樹脂の金型に接している部
分は金型から熱を奪われるために、その周辺部の
プレス圧による流動して成形される樹脂温度より
も、温度が低下するためと考えられる。 These cold marks occur from the time the molten resin is placed on the mold surface until the molten resin begins to flow inside the mold due to press pressure.
The part of the molten resin placed on the mold surface that is in contact with the mold receives heat from the mold, so the temperature of the resin flowing and molding due to the press pressure in the surrounding area is lower than that of the part that is in contact with the mold. It is thought that this is because of this.
本発明者らは鋭意研究の結果、以下に説明する
方法により、このトラブルを解決した。即ち、成
形用溶融樹脂を金型面に置く前に、前以つて成形
用溶融樹脂と同類であつて、成形用溶融樹脂と強
固に融着可能な樹脂からなるシート或いはフイル
ム（以下単にシートと呼ぶ）を、少なくとも、成
形用溶融樹脂を供給する金型面に前以つて設置し
ておき、プレス圧力で溶融樹脂が金型内を流動し
て賦形されると同時に、シートを成形品表面に溶
着一体化するもので、かくすことにより、コール
ドマークのトラブルは解消することが出来る。 As a result of intensive research, the present inventors solved this problem by the method described below. That is, before placing the molten resin for molding on the mold surface, a sheet or film (hereinafter simply referred to as "sheet") made of a resin that is similar to the molten resin for molding and can be firmly fused to the molten resin for molding is prepared. The sheet is placed in advance on at least the surface of the mold that supplies molten resin for molding, and at the same time as the molten resin flows through the mold under press pressure and is shaped, the sheet is placed on the surface of the molded product. The cold mark problem can be solved by hiding it.
ここに用いるシートは成形用溶融樹脂と実用上
十分に溶着するものであればよく、これと同類の
ものであればよい。例えば、シートとして、プロ
ピレンのみから重合して得たホモポリプロピレン
を用いる場合、成形用溶融樹脂としてはホモポリ
プロピレンを用いた場合、及び、プロピレンにエ
チレンを共重合させたエチレン−プロピレン共重
合体を用いる場合も、共に十分な溶着強度が得ら
れ有効であるが、成形用樹脂としてポリエチレン
を用いる場合は実用上十分な溶着強度が得られ
ず、適当でない。即ち、この場合はシートとして
ポリエチレンを用いるべきである。 The sheet used here may be of the same type as long as it can be practically sufficiently welded to the molten resin for molding. For example, when using homopolypropylene obtained by polymerizing only propylene for the sheet, when using homopolypropylene as the molten resin for molding, and when using an ethylene-propylene copolymer obtained by copolymerizing propylene with ethylene. In both cases, sufficient welding strength can be obtained and it is effective; however, when polyethylene is used as the molding resin, practically sufficient welding strength cannot be obtained and it is not suitable. That is, in this case, polyethylene should be used as the sheet.
次にシートの厚みについてであるが、これは状
況に応じて適宜選択すべきである。一般的に云え
ば、あまり厚みが小さすぎると溶融樹脂の熱で、
特に溶融樹脂の温度が高い場合、溶けることがあ
り、またシワなく金型面に設置することが困難と
なり、又厚みが大きすぎると、金型内の溶融樹脂
が流動する空間が少なくなるので望ましくない。
このようにシート厚みは成形品の形状、大きさ、
溶融樹脂の温度、溶融樹脂の金型面への置き方な
どで、適宜選択すべきであるが、一般的には70μ
〜500μのものを用いるのが便利である。 Next, regarding the thickness of the sheet, this should be selected appropriately depending on the situation. Generally speaking, if the thickness is too small, the heat of the molten resin will cause
In particular, if the temperature of the molten resin is high, it may melt and it will be difficult to install it on the mold surface without wrinkles, and if it is too thick, there will be less space for the molten resin to flow in the mold, so this is not desirable. do not have.
In this way, the sheet thickness depends on the shape and size of the molded product.
It should be selected appropriately depending on the temperature of the molten resin, how the molten resin is placed on the mold surface, etc., but generally 70μ
It is convenient to use one with a diameter of ~500μ.
以下に実施例につき説明する。 Examples will be explained below.
実施例
底面が250mm口、高さ30mm、厚さ２mmの箱を成
形する金型を用い、金型温度は40℃とした。この
雌金型をプレス機の上プラテンが油圧で上下運動
し、下プラテンが固定のプレス機の下プラテンに
取付け、この雌金型に大きさ249mm口、厚さ300μ
のホモポリプロピレンシートを置き、この上の中
心部にMFRが20のエチレン−ブロピレン共重合
体を押出機で可塑化した樹脂温度240℃の溶融樹
脂置き、この上から上プラテンに取付けた雄金型
でプレスし、箱成形品を得た。得られた成形品の
外側底面全面に強固にシートが溶着されており、
シート自体の表面がそのまま成形品に現われてい
るので、外観のよい成形品を得た。Example A mold for forming a box with a bottom opening of 250 mm, a height of 30 mm, and a thickness of 2 mm was used, and the mold temperature was set at 40°C. This female mold is attached to the lower platen of a press machine, where the upper platen moves up and down using hydraulic pressure and the lower platen is fixed.
A homopolypropylene sheet is placed, and in the center of this is placed a molten resin made by plasticizing an ethylene-propylene copolymer with an MFR of 20 in an extruder at a resin temperature of 240℃, and a male mold is attached to the upper platen from above. A box molded product was obtained. A sheet is firmly welded to the entire outer bottom surface of the resulting molded product.
Since the surface of the sheet itself appeared on the molded product as it was, a molded product with a good appearance was obtained.
比較例
前記実施例で大きな249mm口、厚さ300μのシー
トを用いなかつた以外は実施例と全く同様にして
成形した。ここで得られた成形品の外側底中心部
がほぼ円型に小ジワが多数発生した外観の悪い成
形品となつた。この部分は押出機から溶融樹脂を
雌金型に置いた時に、溶融樹脂が、金型に接した
部分である。Comparative Example Molding was carried out in exactly the same manner as in the Example except that the sheet with a large opening of 249 mm and a thickness of 300 μm was not used in the Example. The molded product thus obtained had a generally circular shape at the center of the outer bottom and had many small wrinkles, resulting in a molded product with a poor appearance. This part is the part where the molten resin comes into contact with the female mold when it is placed from the extruder into the female mold.
Claims (1)
冷却して成形品を得るに際し、少なくとも溶融熱
可塑性樹脂を供給する金型面に、前記溶融熱可塑
性樹脂と同類のシート又はフイルムを前以つて設
置しておき、プレス圧力で溶融熱可塑性樹脂が金
型内を流動して賦形されると同時に、該シート又
はフイルムを成形品表面に溶着一体化することを
特徴とする熱可塑性樹脂のプレス成形方法。1 Place the molten thermoplastic resin on the mold surface, press,
When cooling to obtain a molded product, a sheet or film similar to the molten thermoplastic resin is placed in advance on at least the surface of the mold to which the molten thermoplastic resin is supplied, and the molten thermoplastic resin is heated by press pressure. A method for press-molding a thermoplastic resin, characterized in that the sheet or film is integrally welded to the surface of a molded product while flowing in a mold and being shaped.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57160517A JPS5949916A (en) | 1982-09-14 | 1982-09-14 | Press molding method of thermoplastic resin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57160517A JPS5949916A (en) | 1982-09-14 | 1982-09-14 | Press molding method of thermoplastic resin |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5949916A JPS5949916A (en) | 1984-03-22 |
| JPH0333492B2 true JPH0333492B2 (en) | 1991-05-17 |
Family
ID=15716664
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57160517A Granted JPS5949916A (en) | 1982-09-14 | 1982-09-14 | Press molding method of thermoplastic resin |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5949916A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62172045U (en) * | 1986-04-23 | 1987-10-31 | ||
| US5795526A (en) * | 1993-02-19 | 1998-08-18 | Sumitomo Chemical Company, Limited | Process for producing multilayer molded article |
| WO1994019164A1 (en) * | 1993-02-19 | 1994-09-01 | Sumitomo Chemical Company, Limited | Method for producing multi-layered molded pieces |
| JP2521639B2 (en) * | 1993-06-17 | 1996-08-07 | 株式会社細川製作所 | Manufacturing method of plastic molding integrated with shapeable material |
-
1982
- 1982-09-14 JP JP57160517A patent/JPS5949916A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5949916A (en) | 1984-03-22 |
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