JPS5920664A - Deep-drawing molding sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel deep-drawn sheet most suitable for producing packaging containers with particularly excellent oxygen barrier properties (gas barrier properties).

BACKGROUND ART Vacuum-formed plastic films or sheets are increasingly being used for packaging containers, especially food packaging containers. These deep drawing materials used for vacuum forming etc.
In addition to being vacuum-formable, various other properties are required depending on the requirements of the material to be packaged. For example, mechanical strength, heat resistance, hygiene, gas barrier properties, etc. are particularly important, and gas barrier properties are particularly important in preventing deterioration in the quality of packaged foods.

Conventionally, sheets made by laminating a sealant film onto the main plastic film have been used as deep-drawn materials, but the gas barrier properties of conventional plastic films are still insufficient, so there is a need for better gas barrier properties. There was a demand for a deep-drawn sheet with

In view of the above, as a result of intensive research, the present inventors have discovered a deep-drawn material with unprecedented excellent gas barrier properties, and have achieved the present invention. % or more of acrylonitrile, and has a uniaxial elongation stress F2φ (0, 7k) at 20% elongation at 100°C.
The present invention relates to a deep-drawn sheet characterized in that it is a laminate consisting of a biaxially stretched film and a sealant film that have an average molecular weight of less than g,/mA.

Further, the present invention comprises a thermoplastic film, an acrylic polymer containing ffj% by weight or more of acrylonitrile,
and a three-layer laminate consisting of a biaxially stretched film having a uniaxial stretching stress horse ◎ at 2 (7% elongation) of 0.,?kp/rrrtJ or less at 700°C, and a sealant film. The present invention relates to deep drawing sheets.

The deep-drawn sheet of the present invention has much better gas barrier properties than conventionally known sheets, and also has excellent deep-drawability.

A method for producing an acrylic polymer film with a high AN content and an acrylonitrile content of gS weight M % or more is disclosed in Japanese Patent Publication No. 6-7 Da S6, Japanese Patent Publication No. Sho Sku/,! Although it is already known from fO & No. 9, etc., it has not been produced industrially so far, and the films produced by these methods all have high -axial elongation stress, and the deep drawing of the present invention It is difficult to use for forming sheets. In order to meet the purpose of the present invention, the present inventors have repeatedly studied the characteristics of the film and its manufacturing method, and have determined that the uniaxial elongation stress at 700°C (,
It has been found that a film having an F1a of 0.3 kg/yd (at 20% elongation) can have sufficient deep drawability.

This high AN-containing film with an F2° value of 03,
crow. >Q,,7 kqAyl at a relatively low stretching temperature compared to the production of conventional films, λ, r x , 20.
By biaxially stretching at a low stretching ratio of less than 200%, or by shrinking it by using ordinary biaxially stretched bales, dry heat or moist heat heating, and further adding a number of plasticizers such as ethylene carbonate, dimethylformamide, glycerin, etc. It can be obtained by a method such as zeshinuru contained in a % film. Particularly effective are a method in which a film stretched at a high draw ratio is subjected to wet heating to increase free shrinkage or limited shrinkage, and a method in which a small amount of plasticizer is added.

Here, the crow. To be more precise, Karasu 0 is l
A sample with a width of Qtnm and a length of '7Qmm was gripped with a gripping length of zotrrm, and the sample was 000%/mt in air at 100''C.
Elongation at a tensile speed of R1. It refers to the force at 20% elongation (It She).

The thickness of the AN film in the present invention is not particularly limited and is appropriately selected depending on the intended use of the deep-drawn product, but a film having a thickness of approximately 5-SOμ, particularly 10 to 30μ, is used.

Sealant film is a film that is used by laminating the deep drawing sheet to the main film to heat and adhere it to the base sheet etc. in order to manufacture containers, and is usually made of polyethylene, polypropylene, ionomer, polyvinyl chloride, polypropylene, etc. tenhabori (ethylene-vinyl acetate),
Polystyrene, poly(ethylene-propylene), poly(
Films such as ethylene-acrylic acid ester) and polycarbonate can be obtained.

As the thermoplastic film used in the present invention, 6, polyester, polyamide Fino X-mukami, etc.
Among the sealant films mentioned above, films of polypropylene, polyvinyl chloride, polystyrene, polycarbonate, etc. can also be used.

Lamination of the acrylic film and the sealant film, or the acrylic film and the thermoplastic film, can be carried out by a commonly used film lamination method, such as an extrusion lamination method, a wet lamination method, a dry lamination method, or a hot melt lamination method. At this time, in order to improve adhesiveness, the surface of the film can be previously subjected to corona discharge treatment, flame treatment, chemical treatment with an oxidizing agent, acid, alkali, etc., or coating with a base agent. Furthermore, various adhesives can be used. for example,
Thermosetting resins such as phenol-based, furan-based, urea-based, melamine-based, polyester-based, polyurethane-based, epoxy-based, silicone-based, etc., vinyl acetate, ethylene-vinyl acetate copolymer, and its partial hydrolyzate, ethylene- Acrylic acid copolymer, polyvinyl butyral, acrylic, thermoplastic resin such as polyamide, butadiene-acrylonitrile rubber, neoprene, other rubber conductors, etc.
Adhesives whose main components are glue, casein, natural resin, gum arabic, etc. or 21 WI or more can be mentioned.

The laminated sheet molding method includes free blow molding method,
A vacuum forming method, a plug forming method, a pressure forming method, etc. can be used, but deep drawing with a large curvature or depth is not preferred.

Next, examples will be shown.

Example: After wet film forming of an acrylonitrile copolymer (molecules jEt 10,000) consisting of % acrylonitrile qF and methyl acrylate, the F2B value was changed by biaxially stretching the stretching ratio. film (approximately 20μ)
using a urethane adhesive to attach a polystyrene film (i
oop) and vacuum forming test M (drape forming method 2 radius of curvature Jw, depth jWrM, 10!; °C, convex top surface acrylic p-nitrile film) was performed. The results are shown in Table/.

Table 7 Example/Example/Sample Na: Unstretched polypropylene film (50μ) on both sides of the r polyacrylonitrile film
were bonded together using an ester-urethane adhesive to produce a three-layer laminate sheet. When a vacuum forming test (710° C., depth 10 rtrm) similar to Example 1 was conducted, good forming was possible to a depth of 10 m without any twitching or cracking.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] (]), ff &heavy'! a, consisting of an acrylic polymer containing % or more of acrylonitrile, and at 700°C,
Uniaxial elongation stress at 0% elongation. A deep drawing sheet, characterized in that it is a laminate consisting of a biaxially stretched film and a sealant film, each of which has a 0.03 Yutsukuda or less, and a sealant film. (2), a thermoplastic film, consisting of an acrylic polymer containing gz weight % or more of acrylonitrile;
At ``C, the uniaxial elongation stress F20 at 20% elongation is 0
1. A deep-drawn sheet characterized by being a three-layer laminate comprising a biaxially stretched film having a thickness of 3 or less and a sealant film.