JPS58124646A - Composite resin layer - 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 composite resin layer made of a resin that firmly adheres to a vinyl chloride IJ resin and a resin.

Polyvinylidene chloride resin film (PVDC film) has a high barrier property against moisture and gas, so it is widely used as a food packaging film, but it is expensive, has low temperature flexibility, heat sealability,
゛Also, there was a drawback in oil resistance. In order to compensate for this drawback, several types of resins are laminated.

Methods of laminating two or several types of resin include 1)
A method of bonding two types of films that have already been formed,
2)! There are two methods: 3) a method in which each layer is adhered in a molten state to form a film on a molded product by applying it in a liquid or emulsion form; The third method is an ideal method for obtaining a laminate in terms of cost and time, since several types of synthetic resins are directly laminated in a molten state and extruded. However, PVDC thread resin has poor adhesion with other resins, and there is little lamination flexibility in such a molten state.

Conventionally, ethylene vinyl acetate copolymer resins, ethylene acrylic ester copolymer resins, and styrene-butadiene copolymer resins are known as resins that can be bonded to PVDC resins, but all of these resins have adhesive properties due to their oil and fat content. It is easily eroded, and peeling from the PVDC resin is likely to occur particularly when the operating temperature is high or when the article is heat-killed while packaged. In addition, these resins have poor solvent resistance,
Due to their low strength, films combined with these resins had limited uses.

As a result of extensive research, the present inventors have discovered a resin in which a material selected from the group of polyurethane, vinyl chloride-ethylene vinyl acetate grafted product, and polybutadiene is mixed with ethylene vinyl acetate copolymer or ethylene acrylate copolymer. The inventors have also discovered that the film has improved oil resistance, solvent resistance, and strength compared to single-m resin films, and that the resin also has excellent adhesion to PVDC resins.

The PVDC resin referred to in the present invention mainly consists of vinylidene chloride, vinyl chloride, alkyl acrylate,
It is a binary or multi-component copolymer made by copolymerizing acrylic acid, acrylonitrile, and other copolymer components.

The polyurethane used in the present invention refers to a polyurethane that has thermoplasticity and is prepared so that it can be processed by a thermoplastic resin processing machine. 30-5% of ethylene vinyl acetate
Contains 0 electric charge.

The composite resin layer Fi of the present invention is obtained by a coextrusion method, and various blend ratios of the mixed resins are appropriately selected depending on the required performance.

Examples of the present invention will be explained below, but the present invention is not limited thereto.

In addition, parts in examples and reference examples, and rice cakes are tt parts by weight, respectively.
*Decrease m%.

Example 1 By using an extruder at a blend ratio of 19% vinyl-containing ethylene-vinyl acetate and thermoplastic polyurethane, each mixed resin pellet was extruded at 180°C using an extruder. Obtained.

The mixed pellets and PVDC thread resin were melted in a separate extruder and fed to a coextrusion film forming apparatus with a 3NI T-die (7) in which the center layer was PVI (C thread balance layer). 30
μ, both outer layers are mixed resin layers, each 1υ/'tt Br 5
(A three-layer film of Jμ was molded. A sample of this film with a width of 15 cm and a length of 1 eas was cut out and one end of one side of the film was forcibly peeled off to measure the peel strength.
Shown in 1.

REFERENCE EXAMPLE T II Theory A Sifilm was formed using the ethylene vinyl acetate and PVI resin used in Example 1 using the same film forming method as in Example 1, and the peel strength was measured using the same measuring method. The result is the first
9.

Table 1 Example 2 Reference Example 2 The film used in Example 1 and Reference Example 1 was treated with animal oil (
The laminate was soaked into pork fat (1jLc) for 30 minutes and changes in appearance were observed. As a result, in a film using an adhesive resin that does not contain thermoplastic polyurethane, the adhesive resin layer swells significantly, wrinkles appear in the film, and the film is easily peeled off with a small amount of force. In place of the plastic polyurethane, a composition in which vinyl chloride was grafted onto ethylene vinyl acetate was used and melt-kneaded in the same manner as in Example 1 to produce various resin compositions. Laminated films were formed using these compositions and their peel strengths were measured. The result is the second
Shown in the table.

Example 4 In the same manner as in Example 1.3, a similar film was prepared using a composition prepared by melt-mixing ethylene vinyl acetate and polybutadiene, and its peel strength was measured. The results are shown in Table 3.

Example 5 Using the laminated films of Example 4 and Reference Example 1, an abuse resistance test was conducted. In the abuse resistance test, the contents are packaged, heat-treated, stored at a specified temperature for a certain period of time, and the package is dropped over a distance of 30 seconds under the same temperature conditions. 1.5 m
Do a drop test. If there is no breakage or pinhole in the package even if it is dropped, repeat the test up to three times, and if there are no abnormalities, it will be passed.

As a result of this test, the failure rate of the film of Example 4 was O~
296 and tl have no problems in practical use. 'Furthermore, the rejection rate of the film of Reference Example 1 was higher than Filo%, and it could not be put to practical use.

As shown in the Examples and Comparative Examples above, the composite resin layer of the present invention exhibits excellent adhesion to PVDC resin, while
This is a composite resin layer that compensates for the drawbacks of DC resin.

Claims (1)

[Claims] It is not a composite resin layer of a vinylidene chloride resin layer and a resin that firmly adheres to the resin layer, and the adhesive resin is an ethylene vinyl acetate copolymer or an ethylene acrylic acid ester copolymer, polyurethane, polybutadiene, or vinyl chloride. A composite resin layer comprising a mixed resin selected from the group of grafted products of ethylene vinyl acetate and ethylene vinyl acetate.