JPH0584729B2 - - Google Patents
Info
- Publication number
- JPH0584729B2 JPH0584729B2 JP17083088A JP17083088A JPH0584729B2 JP H0584729 B2 JPH0584729 B2 JP H0584729B2 JP 17083088 A JP17083088 A JP 17083088A JP 17083088 A JP17083088 A JP 17083088A JP H0584729 B2 JPH0584729 B2 JP H0584729B2
- Authority
- JP
- Japan
- Prior art keywords
- sheet
- heating
- mold
- vacuum forming
- laminated
- 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
- -1 polypropylene Polymers 0.000 claims description 32
- 239000004743 Polypropylene Substances 0.000 claims description 29
- 238000010438 heat treatment Methods 0.000 claims description 29
- 229920001155 polypropylene Polymers 0.000 claims description 29
- 238000000034 method Methods 0.000 claims description 26
- 238000007666 vacuum forming Methods 0.000 claims description 25
- 239000006260 foam Substances 0.000 claims description 22
- 238000005187 foaming Methods 0.000 claims description 22
- 229920005989 resin Polymers 0.000 claims description 20
- 239000011347 resin Substances 0.000 claims description 20
- 229920005992 thermoplastic resin Polymers 0.000 claims description 8
- 239000004744 fabric Substances 0.000 description 16
- 238000000465 moulding Methods 0.000 description 11
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 7
- 229920001169 thermoplastic Polymers 0.000 description 6
- 239000004416 thermosoftening plastic Substances 0.000 description 6
- 230000007423 decrease Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000004793 Polystyrene Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229920002223 polystyrene Polymers 0.000 description 3
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 239000011256 inorganic filler Substances 0.000 description 2
- 229910003475 inorganic filler Inorganic materials 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 229910052570 clay Inorganic materials 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920001707 polybutylene terephthalate Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 229920000306 polymethylpentene Polymers 0.000 description 1
- 239000011116 polymethylpentene Substances 0.000 description 1
- 229920005990 polystyrene resin Polymers 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
- 239000004408 titanium dioxide Substances 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
- B29C44/56—After-treatment of articles, e.g. for altering the shape
- B29C44/5627—After-treatment of articles, e.g. for altering the shape by mechanical deformation, e.g. crushing, embossing, stretching
- B29C44/5636—After-treatment of articles, e.g. for altering the shape by mechanical deformation, e.g. crushing, embossing, stretching with the addition of heat
-
- 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
- B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
- B29C51/08—Deep drawing or matched-mould forming, i.e. using mechanical means only
-
- 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
- B29C2791/00—Shaping characteristics in general
- B29C2791/004—Shaping under special conditions
- B29C2791/006—Using vacuum
-
- 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
- B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
- B29C51/10—Forming by pressure difference, e.g. vacuum
-
- 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
- B29K2023/10—Polymers of propylene
- B29K2023/12—PP, i.e. polypropylene
-
- 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
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/04—Condition, form or state of moulded material or of the material to be shaped cellular or porous
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、ポリプロピレン系樹脂発泡シートを
中心層とし、その両面に熱可塑性樹脂フイルムを
積層、接着した発泡ポリプロピレン系樹脂シート
（以下、このシートを原反シートという）の両面
真空成形方法に関するものであり、特に短時間に
加熱して成形できるようにした原反シートの両面
真空成形方法に関するものである。Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a foamed polypropylene resin sheet (hereinafter referred to as this sheet) which has a foamed polypropylene resin sheet as the central layer and thermoplastic resin films laminated and bonded to both sides of the foamed polypropylene resin sheet. The present invention relates to a double-sided vacuum forming method for a raw sheet (referred to as a raw sheet), and particularly to a double-sided vacuum forming method for a raw sheet that can be heated and molded in a short time.
（従来の技術）
従来、熱可塑性発泡樹脂よりなるシートの成形
方法としては、一次発泡した発泡シートを加熱し
て二次発泡させると共に可塑状態とし、同時に雌
型、または雄型の一方を減圧にして発泡シートを
型に密着させる方法（通常、片面真空成形方法と
いう）が知られている。しかし、通常、一次発泡
した発泡シートは経時変化により二次発泡力は低
下する。又、一次発泡シートのシート製造時の条
件変化により二次発泡力にバラツキが発生する。
このため、従来の成形方法では、成形品の肉厚が
バラツキ、引いては成形品の薄肉化よる強度不
足、あるいは成形品間の嵌合性が不良となつて良
品の収得率が低下する。殊に、発泡ポリプロピレ
ンシートは発泡力が弱いためにこの片面真空成形
ではポリプロピレン発泡シートは潰れ成形後、厚
みが著しく減少するのである。この片面真空成形
方法の問題点を解決する方法として、例えば雌雄
両金型の間に所定の空隙を有し、金型外周部分に
クランプを設け、且つ50〜60℃に温調した雄金型
を用いて加熱可塑化された熱可塑性発泡樹脂シー
トを型締めしたのち、雌雄両型より真空度−500
mmHg（ゲージ圧）以上で真空減圧してシートを空
隙内いつぱいに断熱膨張させて所定の形状に成形
したのち冷却し、金型内に気体を導入して常圧に
戻し、次いで型を開いて成形品を取り出すことを
特徴とする熱可塑性発泡樹脂シートの両面真空成
形方法が知られている（特公昭59−1184号参照）。
そして、この両面真空成形方法によつてポリスチ
レン、スチレンを主体とし、スチレンと共重合し
得るブタジエン、メチルメタアクリレート等の発
泡成形品を成形することができる。しかし、この
方法によつてポリプロピレンの一次発泡シートを
両面真空成形した場合、ポリスチレンまたはスチ
レンを主体としたスチレン共重合体のような二次
発泡成形品が得られない。その理由としては、ポ
リプロピレンの一次発泡シートは、気泡がシート
の厚み方向に並び易いために連通化しやすく、そ
のため二次発泡の際に気泡が連通化すると共に発
泡ガスが表面より散逸し、二次発泡により目的と
する発泡倍率の成形品が得られない欠点があつ
た。(Prior art) Conventionally, the method of molding sheets made of thermoplastic foam resin involves heating a primarily foamed sheet to cause secondary foaming and making it plastic, and at the same time reducing the pressure in either the female mold or the male mold. A method is known in which a foamed sheet is brought into close contact with a mold (usually referred to as a one-sided vacuum forming method). However, the secondary foaming power of a foamed sheet that has undergone primary foaming usually decreases due to changes over time. Moreover, variations in the secondary foaming force occur due to changes in conditions during the production of the primary foam sheet.
For this reason, in the conventional molding method, the thickness of the molded product varies, which leads to insufficient strength due to thinning of the molded product, or poor fit between the molded products, resulting in a decrease in the yield of non-defective products. In particular, since the foaming power of the foamed polypropylene sheet is weak, the thickness of the foamed polypropylene sheet is significantly reduced after the single-sided vacuum forming process collapses the sheet. As a method to solve the problems of this one-sided vacuum forming method, for example, the male mold has a predetermined gap between the male and female molds, a clamp is provided on the outer periphery of the mold, and the temperature is controlled at 50 to 60°C. After mold-clamping the thermoplastic foamed resin sheet heated and plasticized using
The sheet is vacuum-depressurized at mmHg (gauge pressure) or above to adiabatically expand the sheet into the cavity, molded into a predetermined shape, cooled, and returned to normal pressure by introducing gas into the mold.Then, the mold is opened. A double-sided vacuum forming method for a thermoplastic foamed resin sheet is known, which is characterized by removing the molded product (see Japanese Patent Publication No. 1184/1984).
By this double-sided vacuum forming method, it is possible to form a foam molded product mainly composed of polystyrene or styrene, butadiene, methyl methacrylate, etc. that can be copolymerized with styrene. However, when a primary foamed sheet of polypropylene is vacuum-formed on both sides by this method, a secondary foamed molded product such as polystyrene or a styrene copolymer mainly composed of styrene cannot be obtained. The reason for this is that in the primary foamed polypropylene sheet, the air bubbles tend to line up in the thickness direction of the sheet, making them easy to communicate with each other. Therefore, during secondary foaming, the air bubbles become interconnected and the foaming gas dissipates from the surface. There was a drawback that molded products with the desired expansion ratio could not be obtained due to foaming.
そこで、本発明者は、先に、上記の欠点を解決
する手段として、原反シートを加熱、軟化させた
後、金型間隙を加熱軟化した原反シートの厚みの
1.0〜2.5倍に調整した真空成形金型で両面より真
空に減圧にしながら成形する方法を発明し、一応
の成果を得た。この方法では、原反の加熱軟化手
段として遠赤外線ヒーターオーヴンによる輻射加
熱であるため、炉内加熱時間が45〜50秒という長
時間を要するという欠点があつた。 Therefore, as a means to solve the above-mentioned drawbacks, the present inventor first heated and softened the original fabric sheet, and then changed the thickness of the heated and softened original fabric sheet into the mold gap.
We invented a method of molding while reducing the pressure from both sides using a vacuum molding mold adjusted to 1.0 to 2.5 times, and achieved some results. In this method, radiation heating using a far-infrared heater oven is used as a means for heating and softening the original fabric, so there is a drawback that heating time in the oven is long, 45 to 50 seconds.
（解決すべき課題）
本発明者は、更に、上記の欠点を解決するた
め、原反シートより強度及び耐熱性の良い寸法及
び形状の安定した成形品を短時間で成形する方法
を種々検討した結果、本発明を完成するに至つた
もので、本発明の目的は原反シートより強度、寸
法及び形状の安定した成形品を短時間で成形する
ための積層シートの両面真空成形方法を提供する
にある。(Problems to be Solved) In order to solve the above-mentioned drawbacks, the present inventor further investigated various methods of molding a molded product with stable dimensions and shape that has better strength and heat resistance than the original sheet in a short time. As a result, the present invention has been completed, and the purpose of the present invention is to provide a method for double-sided vacuum forming of laminated sheets for forming molded products with more stable strength, dimensions, and shape than original sheets in a short time. It is in.
（課題を解決するための手段）
すなわち、本発明は真空成形可能な雌雄型の金
型による発泡ポリプロピレン系樹脂シートの両面
真空成形方法であつて、前記発泡ポリプロピレン
系樹脂シートとして発泡倍率が1.2〜5.5倍の範囲
にあるポリプロピレン系樹脂発泡シートを中心層
とし、その両面に熱可塑性樹脂フイルムをそれぞ
れ積層、接着した積層発泡シートを使用し、160
℃以上190℃以下の範囲の温度に加熱した一対の
熱板にて、熱板間の距離が前記積層発泡シートの
厚みの５％〜30％圧縮した条件下で前記積層発泡
シートを圧縮加熱して軟化せしめた後、間隙を該
積層発泡シートの加熱軟化後の厚みの1.0〜2.5倍
に調整した真空成形可能な雌雄型の金型を使用
し、両面より真空に減圧しながら成形することを
特徴とする積層シートの両面真空成形方法であ
る。(Means for Solving the Problems) That is, the present invention is a method for double-sided vacuum forming of a foamed polypropylene resin sheet using male and female molds capable of vacuum forming, wherein the foamed polypropylene resin sheet has an expansion ratio of 1.2 to 1.2. Using a laminated foam sheet with a polypropylene resin foam sheet in the range of 5.5 times as the center layer and thermoplastic resin films laminated and bonded on both sides, the 160
The laminated foam sheet is compressed and heated using a pair of hot plates heated to a temperature in the range of not less than 190 degrees Celsius, and the distance between the hot plates is compressed by 5% to 30% of the thickness of the laminated foam sheet. After softening, the laminated foam sheet is molded using vacuum-formable male and female molds with a gap adjusted to 1.0 to 2.5 times the thickness of the laminated foam sheet after heating and softening, while reducing the pressure to vacuum from both sides. This is a double-sided vacuum forming method for laminated sheets.
本発明について更に詳細に説明する。 The present invention will be explained in more detail.
先ず、本発明で使用できる原反シートの発泡ポ
リプロピレン系樹脂は、ポリプロピレンを主成分
とするが、これと混和可能な熱可塑性樹脂又は無
機充填剤を含有したものも含まれる。そして、こ
の発泡ポリプロピレン系樹脂と混和可能な熱可塑
性樹脂としては耐熱性ポリスチレン、ポリメチル
メタアクリレートなどがある。また、無機充填剤
としてはタルク、二酸化チタン、クレー、シリカ
及びアルミナなどである。 First, the foamed polypropylene resin of the raw sheet that can be used in the present invention has polypropylene as its main component, but it also includes those containing thermoplastic resins or inorganic fillers that are miscible with polypropylene. Thermoplastic resins that can be mixed with this foamed polypropylene resin include heat-resistant polystyrene, polymethyl methacrylate, and the like. Inorganic fillers include talc, titanium dioxide, clay, silica, and alumina.
そして、本発明における原反シートにおける発
泡ポリプロピレン系樹脂シートの発泡倍率は1.2
〜5.5である。その理由は、この発泡ポリプロピ
レン系樹脂シートは押出し成形によつて得るので
あるが、発泡倍率が5.5以上のものは、押出し成
形時に波縞模様が発生し、伸びにバラツキが生
じ、成形品の厚さが不均一になり、又亀裂が生ず
るからである。また、発泡倍率が1.2以下のもの
は、発泡力が殆どなく、型内で両面真空成形を行
なつても所定の肉厚のものが得られない。好適に
は発泡率1.5倍以上2.5倍以下である。 The foaming ratio of the foamed polypropylene resin sheet in the raw sheet in the present invention is 1.2.
~5.5. The reason for this is that this foamed polypropylene resin sheet is obtained by extrusion molding, but if the foaming ratio is 5.5 or more, a wave striped pattern will occur during extrusion molding, and the elongation will vary, resulting in the thickness of the molded product. This is because the coating becomes uneven and cracks occur. Moreover, if the foaming ratio is 1.2 or less, there is almost no foaming power, and even if double-sided vacuum forming is performed in a mold, a product with a predetermined thickness cannot be obtained. The foaming ratio is preferably 1.5 times or more and 2.5 times or less.
本発明においては原反シートが低倍率で薄いた
めに、これを輸送する際の輸送効率がよく、成形
品において所望の発泡倍率を有する成形品を得る
ことができる。 In the present invention, since the original fabric sheet has a low magnification and is thin, the transportation efficiency when transporting it is good, and a molded article having a desired expansion ratio can be obtained.
本発明における原反シートは、低発泡ポリプロ
ピレン系樹脂シートの両面には熱可塑性樹脂シー
トを積層、接着されている。先に述べたように、
ポリプロピレン系樹脂発泡シートの気泡は連通化
しており、その為二次加熱において、気体が表面
より既に散逸しているので、所望の発泡倍率の成
形品が得られない。そこで、この発泡シートの両
面に熱可塑性フイルムを接着することと、両面真
空による減圧発泡によつて、所望の発泡倍率の成
形品が得られるようにしたのである。 In the raw sheet of the present invention, thermoplastic resin sheets are laminated and adhered to both sides of a low-foaming polypropylene resin sheet. As mentioned earlier,
The cells in the foamed polypropylene resin sheet are interconnected, and therefore, during secondary heating, gas has already dissipated from the surface, making it impossible to obtain a molded product with the desired expansion ratio. Therefore, by adhering thermoplastic films to both sides of this foamed sheet and performing vacuum foaming using vacuum on both sides, it was possible to obtain a molded product with a desired expansion ratio.
この発泡ポリプロピレン系樹脂シートの両面に
接着する熱可塑性樹脂としては、ポリエチレン、
ポリプロピレン、ポリメチルペンテン、ポリエチ
レンテレフタレート、ポリブチレンテレフタレー
ト等であり、接着手段としては一次発泡シートと
熱可塑性樹脂フイルムとを熱接着したり、或は接
着剤により接着したりする等何れの方法でも良
い。そして、この熱可塑性フイルムの厚さは通常
40〜80ミクロン程度であり、両面のフイルムの厚
さは、同じであつても、また異なつていてもよ
い。 The thermoplastic resin to be bonded to both sides of this foamed polypropylene resin sheet includes polyethylene,
Polypropylene, polymethylpentene, polyethylene terephthalate, polybutylene terephthalate, etc., and any method of adhesion may be used, such as thermal adhesion of the primary foam sheet and thermoplastic resin film, or adhesion with an adhesive. . And the thickness of this thermoplastic film is usually
The thickness of the film on both sides may be the same or different.
次に、この原反シートを成形するに先だつて、
加熱軟化させなければならない。加熱軟化する手
段としては、一対の熱板にて圧縮加熱して軟化さ
せる。熱板の温度は、160℃以上190℃以下の範囲
の温度で、熱板間の距離は前記積層発泡シートの
厚みの５％―０％圧縮した条件下で圧縮加熱して
軟化させるのが好ましい。熱板の温度が、160℃
以下では、成形時に充分な可塑性が得られず、ま
た190℃以上では発泡層が融着破壊してしまう。 Next, before forming this raw sheet,
Must be heated and softened. As a means for heating and softening, the material is compressed and heated using a pair of hot plates to soften it. The temperature of the hot plates is preferably in the range of 160°C or more and 190°C or less, and the distance between the hot plates is preferably compressed and heated by 5% to 0% of the thickness of the laminated foam sheet to soften it. . The temperature of the hot plate is 160℃
If the temperature is below 190° C., sufficient plasticity will not be obtained during molding, and if the temperature exceeds 190° C., the foam layer will melt and fail.
例えば、発泡倍率2.25倍の厚さ0.95ミリメート
ルの原反シートを外層フイルム側の熱板温度を
182℃、内層の熱板温度を174℃に加熱した熱板を
使用して６秒間加熱した。その際、熱板間の間隙
の値を種々変えて圧縮加熱し、その後、軟化した
原反を24℃の金型で両面真空成形したところ、第
１図に示すような傾向の有ることが判明した。こ
こで、使用した金型は、横120mm、縦100mm、深さ
25mmのの容器の型内形状であつて、側部1.5mm、
底部２mmの間隙をもつている。これらのことから
原反シートの厚みの５％以上、30％以下に熱板間
の距離を圧縮した場合に両面真空成形時に発泡
し、所望の成形品が得られるのであつて、10％〜
20％の圧縮の場合が好適であつた。発泡倍率の低
いシートは当然大きくは圧縮出来ない。30％以上
に圧縮した場合には原反の厚みが縮小変形して肉
厚にバラツキが生じて良好な成形品が得られな
い。 For example, when using a 0.95 mm thick raw sheet with a foaming ratio of 2.25 times, the heating plate temperature on the outer film side is
Heating was performed for 6 seconds using a hot plate heated to 182°C and an inner layer heated to 174°C. At that time, we compressed and heated the material by varying the gap between the hot plates, and then vacuum-formed the softened material on both sides in a mold at 24°C, and it was found that there was a tendency as shown in Figure 1. did. Here, the mold used was 120mm wide, 100mm long, and deep.
The shape of the container inside the mold is 25 mm, and the sides are 1.5 mm.
It has a 2mm gap at the bottom. From these facts, if the distance between the hot plates is compressed to 5% or more and 30% or less of the thickness of the raw sheet, foaming will occur during double-sided vacuum forming, and the desired molded product will be obtained.
A compression of 20% was preferred. Naturally, a sheet with a low expansion ratio cannot be compressed to a large extent. When compressed to 30% or more, the thickness of the original fabric is reduced and deformed, causing variations in wall thickness and making it impossible to obtain a good molded product.
成形条件について述べる。本発明で使用する金
型は、通常の雌型及び雄型よりなる金型である
が、両型に真空減圧でるように細孔を設ける必要
がある。細孔の孔径としては0.6mm程度で、これ
を真空吸引装置に接続する。 The molding conditions will be described. The mold used in the present invention is a conventional mold consisting of a female mold and a male mold, and it is necessary to provide pores in both molds so that a vacuum can be released. The pores have a diameter of about 0.6 mm and are connected to a vacuum suction device.
雌型及び雄型の型の間隙は、加熱軟後の原反シ
ートの厚さの1.0〜2.5倍に調整する。この間隙
は、二次発泡後の成形品の強度に影響し、2.5倍
を越えると発泡層の倍率が上がり、極端に曲げ強
度が低下する。また、1.0倍未満では曲げ強度の
向上に寄与しない。 The gap between the female and male molds is adjusted to 1.0 to 2.5 times the thickness of the original sheet after being heated and softened. This gap affects the strength of the molded product after secondary foaming, and if it exceeds 2.5 times, the magnification of the foam layer will increase and the bending strength will extremely decrease. Moreover, if it is less than 1.0 times, it does not contribute to improvement in bending strength.
金型の温度は５℃〜40℃が好ましい。先に述べ
たポリスチレン系樹脂の両面真空成形法では、金
型両面より真空減圧して三次発泡させるために可
塑化状態を維持する必要上、50〜60℃に加熱保持
するのであるが、本発明では、原反シートはポリ
プロピレン系発泡シートの両面に熱可塑性フイル
ムを積層しているが、ポリプロピレン系樹脂は比
熱が大きく、冷却が悪いので金型の温度を50℃以
上にすると変形する傾向がある。ただ、金型の温
度があまり低温になると加熱軟化した原反シート
を冷却することとなり、可塑性が失われて充分な
真空成形ができないこととなる。また、両面金型
における真空度としては、真空度−500mmHg以上
が用いられる。 The temperature of the mold is preferably 5°C to 40°C. In the double-sided vacuum forming method for polystyrene resin mentioned above, the pressure is reduced from both sides of the mold to maintain the plasticized state in order to perform tertiary foaming, so the temperature is maintained at 50 to 60°C. In this case, the original fabric sheet is made by laminating thermoplastic films on both sides of a polypropylene foam sheet, but polypropylene resin has a large specific heat and is difficult to cool, so it tends to deform when the mold temperature is raised to 50°C or higher. . However, if the temperature of the mold becomes too low, the raw sheet that has been softened by heating will have to be cooled down, resulting in loss of plasticity and insufficient vacuum forming. Further, the degree of vacuum in the double-sided mold is −500 mmHg or more.
本発明の成形方法を図面について説明する。第
２図は本発明の両面真空成形過程の一例を示した
説明図であり、第３図はその際の加熱工程につい
ての説明図である。第２図に示すように、本発明
において使用する装置は、加熱部分Ａと両面真空
成形部分Ｂとからなる。加熱部分Ａに使用する加
熱装置の一例を第３図に示す。加熱装置として使
用する加熱プレスは、通常の加熱プレスであつ
て、加熱ヒーター３上に加熱板２を設けてあり、
これが原反シート１に接する。更に、両熱板の間
隙を所定の間隔になるようにストツパー４が設け
られている。先づ、発泡ポリプロピレンシートの
両面にポリプロピレンフイルムを接着した原反シ
ート１を加熱プレスの間に置く（ａ図参照）。加
熱プレスは、ストツパー４によつて規制される位
置迄、シリンダ―５を作動させることによつて熱
板２を降下させ、原反シート１の両面に接触させ
て圧縮加熱させる（ｂ図参照）。加熱された原反
シートは軟化し、所望の可塑性を有する。次に、
加熱板の圧縮を開き、続いて、この加熱軟化した
可塑性を有する原反シート１を両面真空成形機に
移動させる。両面真空成形機は真空吸引孔６を有
する雌型７及び雄型８からなるプレス機である。
上記の加熱軟化した可塑性を有する原反シート１
を雌型７と雄型８の間に挿入し、型を閉じ、型内
を減圧にして成形する。ここで、原反シート１の
中心層は発泡し、所望の成形品９が得られる。 The molding method of the present invention will be explained with reference to the drawings. FIG. 2 is an explanatory diagram showing an example of the double-sided vacuum forming process of the present invention, and FIG. 3 is an explanatory diagram of the heating process at that time. As shown in FIG. 2, the apparatus used in the present invention consists of a heating section A and a double-sided vacuum forming section B. An example of a heating device used in heating portion A is shown in FIG. The heating press used as a heating device is a normal heating press, and a heating plate 2 is provided on a heating heater 3.
This contacts the original fabric sheet 1. Further, a stopper 4 is provided to maintain a predetermined gap between the two hot plates. First, an original fabric sheet 1 with polypropylene films adhered to both sides of a foamed polypropylene sheet is placed in a heated press (see figure a). The heating press lowers the hot plate 2 by operating the cylinder 5 to the position regulated by the stopper 4, brings it into contact with both sides of the original fabric sheet 1, and compresses and heats it (see figure b). . The heated raw sheet softens and has desired plasticity. next,
The heating plate is compressed, and then the heated and softened raw sheet 1 having plasticity is transferred to a double-sided vacuum forming machine. The double-sided vacuum forming machine is a press machine consisting of a female die 7 and a male die 8 having vacuum suction holes 6.
The raw sheet 1 having heat-softened plasticity as described above
is inserted between the female mold 7 and the male mold 8, the mold is closed, and the pressure inside the mold is reduced to perform molding. Here, the center layer of the original fabric sheet 1 is foamed, and a desired molded product 9 is obtained.
更に、実施例をもつて本発明を具体的に説明す
る。 Further, the present invention will be specifically explained using examples.
実施例
厚さ875ミクロンのポリプロピレン発泡シート
（発泡シートの坪量405g／m2、発泡倍率2.25倍）
を中心層とし、外側に厚さ80μ、内側に厚さ55μ
のそれぞれのポリプロピレンフイルムを接着し、
全坪量526.5g／m2、全肉厚1010μからなる積層発
泡シートを原反シートとして使用した。Example: Polypropylene foam sheet with a thickness of 875 microns (basis weight of foam sheet 405 g/m 2 , foaming ratio 2.25 times)
The center layer is 80μ thick on the outside and 55μ thick on the inside.
Glue each polypropylene film,
A laminated foam sheet having a total basis weight of 526.5 g/m 2 and a total wall thickness of 1010 μm was used as the original fabric sheet.
一方、原反の外層フイルム側の熱板の表面温度
を182℃に、内層フイルム側の熱板の表面温度を
174℃にそれぞれ調整し、且つ、両熱板間のクリ
アランスが0.8mmである一対の熱板間の前記原反
を挟持し、６秒間加熱、加圧して原反を軟化させ
た。 On the other hand, the surface temperature of the hot plate on the outer film side of the original fabric was set to 182℃, and the surface temperature of the hot plate on the inner layer film side was set to 182℃.
The original fabric was held between a pair of hot plates each adjusted to 174°C and with a clearance of 0.8 mm, and heated and pressurized for 6 seconds to soften the original fabric.
続いて、この軟化した原反をマツチモールド式
両面真空成形金型を使用して、横120mm、縦00mm、
深さ25mmの容器形状をした成型品に成形した。す
なわち、24℃の温度にある雌雄金型間に前記軟化
した原反を挿入し、両面真空に減縮し、金型内で
発泡させて成型品を得た。 Next, this softened original fabric was molded into a mold with a width of 120 mm, a height of 00 mm, and
It was molded into a container-shaped product with a depth of 25 mm. That is, the softened original fabric was inserted between male and female molds at a temperature of 24°C, vacuum was applied on both sides, and foaming was performed within the molds to obtain a molded product.
得られた成型品の側面の肉厚は1.4mm、底面の
肉厚は2.2mmで、この成形品を得るための１シヨ
ツトに要した時間は、６秒であつた。 The side wall thickness of the obtained molded product was 1.4 mm, and the bottom wall thickness was 2.2 mm, and the time required for one shot to obtain this molded product was 6 seconds.
（効 果）
以上述べたように、本発明により原反としてポ
リプロピレン系樹脂積層発泡シートを使用し、こ
れを圧縮加熱して軟化させ、両面真空成型するこ
とにより、成形に要する時間が、従来１シヨツト
に45〜50秒であるのが、４〜６秒と極めて短縮で
きので生産性が高められ、また、従来の片面真空
成型の場合のように成形後の厚みの減少が無く、
得られた成形品の性質は強度、耐熱性等の点にお
いて優れている等の効果を奏するのである。(Effects) As described above, according to the present invention, by using a polypropylene resin laminated foam sheet as the raw material, compressing and heating it to soften it, and vacuum forming it on both sides, the time required for molding is reduced compared to the conventional method. The shot time can be reduced from 45 to 50 seconds to 4 to 6 seconds, increasing productivity, and there is no decrease in thickness after molding, unlike in the case of conventional single-sided vacuum forming.
The properties of the obtained molded product are excellent in terms of strength, heat resistance, etc.
第１図は原反シートを加熱軟化する際の熱板間
隙と得られる成形品の厚さとの関係図、第２図は
本発明方法の工程を示した説明図、第３図は本発
明方法における加熱工程を示した説明図である。
Ａ…加熱部分、Ｂ…両面真空成形部分、１…原
反シート、２…加熱板、３…加熱ヒーター、４…
ストツパー、５…シリンダー、６…真空吸収孔、
７…雌型、８…雄型、９…成形品。
Fig. 1 is a diagram showing the relationship between the gap between the hot plates when heating and softening the raw sheet and the thickness of the molded product obtained, Fig. 2 is an explanatory diagram showing the steps of the method of the present invention, and Fig. 3 is the method of the present invention. It is an explanatory view showing a heating process in. A... Heating part, B... Double-sided vacuum forming part, 1... Raw sheet, 2... Heating plate, 3... Heating heater, 4...
Stopper, 5...Cylinder, 6...Vacuum absorption hole,
7... Female mold, 8... Male mold, 9... Molded product.
Claims (1)
プロピレン系樹脂シートの両面真空成形方法であ
つて、前記発泡ポリプロピレン系樹脂シートとし
て発泡倍率が‘1.2〜5.5倍の範囲にあるポリプロ
ピレン系樹脂発泡シートを中心層とし、その両面
に熱可塑性樹脂フイルムをそれぞれ積層、接着し
た積層発泡シートを使用し、160℃以上190℃以下
の範囲の温度に加熱した一対の熱板にて、前記積
層発泡シートを圧縮加熱して軟化せしめた後、金
型の間〓を該積層発泡シートの加熱軟化後の厚み
の1.0〜2.5倍に調整した真空成形可能な雌雄型の
金型を使用し、両面より真空に減圧しながら成形
することを特徴とする積層シートの両面真空成形
方法。1. A method for double-sided vacuum forming of a foamed polypropylene resin sheet using male and female molds capable of vacuum forming, wherein the foamed polypropylene resin sheet has a foaming ratio of 1.2 to 5.5 times. A laminated foam sheet is used as the center layer, and thermoplastic resin films are laminated and bonded on both sides of the laminated foam sheet, and the laminated foam sheet is compressed using a pair of hot plates heated to a temperature in the range of 160°C to 190°C. After heating and softening, the pressure is reduced to vacuum from both sides using a vacuum-formable male and female mold with a space between the molds adjusted to 1.0 to 2.5 times the thickness of the laminated foam sheet after heating and softening. A double-sided vacuum forming method for laminated sheets, characterized by forming the sheets while forming the sheets.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17083088A JPH0222031A (en) | 1988-07-11 | 1988-07-11 | Vacuum molding of both sides of laminated sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17083088A JPH0222031A (en) | 1988-07-11 | 1988-07-11 | Vacuum molding of both sides of laminated sheet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0222031A JPH0222031A (en) | 1990-01-24 |
| JPH0584729B2 true JPH0584729B2 (en) | 1993-12-03 |
Family
ID=15912118
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17083088A Granted JPH0222031A (en) | 1988-07-11 | 1988-07-11 | Vacuum molding of both sides of laminated sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0222031A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007237735A (en) * | 2006-02-10 | 2007-09-20 | Sumitomo Chemical Co Ltd | Manufacturing method for expanded molded article made of thermoplastic resin |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5116881A (en) * | 1990-03-14 | 1992-05-26 | James River Corporation Of Virginia | Polypropylene foam sheets |
| JP2002018887A (en) | 2000-07-12 | 2002-01-22 | Chisso Corp | Foamed molded body of polypropylene resin |
| JP2002331572A (en) | 2001-05-08 | 2002-11-19 | Chisso Corp | Molding method for foamed polypropylene resin sheet, and foamed molded body |
| GB2458333B (en) | 2008-04-15 | 2013-11-13 | Gurit Uk Ltd | Structural foam and manufacture thereof |
-
1988
- 1988-07-11 JP JP17083088A patent/JPH0222031A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007237735A (en) * | 2006-02-10 | 2007-09-20 | Sumitomo Chemical Co Ltd | Manufacturing method for expanded molded article made of thermoplastic resin |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0222031A (en) | 1990-01-24 |
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