JPH0453883A - Surface protective film - Google Patents

Abstract

PURPOSE:To improve initial self-bonding properties and weatherability and to decrease change with time and increase in self-bonding properties at high temp. by laminating a pressure-sensitive adhesive layer consisting of an ehtylene- n-butyl acrylate copolymer on a base material layer consisting of a polyolefin resin. CONSTITUTION:A material (A) forming a base material layer is obtd. by compounding a polyolefin resin and, if necessary, a photostabilizer, a UV absorbing agent, an anti-oxidant, etc. Separately, a material (B) forming a pressure- sensitive adhesive layer is obtd. by compounding an ethylene-n-butyl acrylate copolymer and, if necessary, a softening agent, a UV absorber, an anti-oxidant, etc. The components A and B are co-extruded to laminate the base material layer and the pressure-sensitive adhesive layer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is for temporarily adhering to the surface of a synthetic resin board, decorative plywood, metal plate, etc. to protect the surface from dust and damage. The present invention relates to a surface protection film used for, and more specifically, to a surface protection film having an adhesive layer with excellent heat resistance, weather resistance, extrusion suitability, film formability, etc.

[Conventional technology]

Various surface protection films are commonly used to prevent scratches and stains on the surfaces of synthetic resin boards, decorative plywood, metal plates, etc. during processing or transportation.

A surface protection film generally has a structure in which an adhesive layer is laminated on one side of a base film made of a thermoplastic resin such as a polyolefin resin, and has good adhesion (temporary adhesion). After use, the adhesive must not contaminate various surfaces (it must be easy to remove).

In addition, in the production of surface protection films, from the viewpoint of moldability and productivity, a coextrusion method is often adopted in which the adhesive component and the thermoplastic resin of the base film are extruded together and laminated. (Therefore, it is desired that the adhesive component be suitable for melt extrusion.

Conventionally, various synthetic rubbers, ethylene-vinyl acetate copolymers, or combinations of these polymers and tackifiers have been used as adhesive components for surface protection films (Japanese Patent Laid-Open No. 46-22359, Special Public Service 1986-3
0911 etc.).

However, although the conventional surface protection film has good tackiness at the initial stage of application, the tackiness significantly increases after the film changes over time. Therefore, the surface protection film cannot be easily peeled off from the protected article after use, requiring time and effort to remove the film, and the surface after peeling may be contaminated by the adhesive layer (adhesive residue), and the When peeled off, there were problems such as the base film stretching and breaking.

In particular, if an article with a surface protection film affixed has a surface protection film of 100 to 180
When exposed to high temperatures such as 0.degree. C. or stored at intermediate temperatures of 40 to 60.degree. C. for long periods of time, tackiness tends to increase rapidly.

Furthermore, when an ethylene-vinyl acetate copolymer is used as the main component of the adhesive layer, it is severely degraded by light, and when used outdoors, the adhesiveness increases and it becomes impossible to peel it off from the protected article. This results in adhesive residue.

Therefore, it is desired to improve the adhesive layer, particularly with respect to the adhesiveness when pasting it on various articles and the ability to leave adhesive residue when peeling it off from the article.

[Problem to be solved by the invention]

An object of the present invention is to provide a surface protection film that has good initial tackiness (temporary adhesion), is less likely to change over time or increase in tackiness at high temperatures, and has excellent weather resistance.

As a result of intensive research in order to overcome the problems of the prior art, the present inventor discovered that ethylene-
It has been found that the above object can be achieved by using an n-butyl acrylate copolymer.

Moreover, the ethylene-n-butyl acrylate copolymer has good melt extrusion characteristics and film forming properties, and can be easily formed into a laminated film by coextrusion with the polyolefin resin of the base layer.

The present invention has been completed based on these findings.

[Means for Solving the Problems] According to the present invention, a base material layer made of a polyolefin resin and an adhesive layer made of an ethylene-n-butyl acrylate copolymer are laminated. A surface protection film is provided which is characterized by:

Hereinafter, the configuration of the present invention will be explained in detail.

As the thermoplastic resin constituting the base layer, olefin resins such as polyethylene and polypropylene are preferably used. Depending on the purpose and use, the base material layer may be composed of two or more layers.

Examples of the ethylene-n-butyl acrylate copolymer constituting the adhesive layer include the product name rEnathene.
EA 720-009J, rEnathene E
A 719-009J rEnathene EA 7
05-009J (Phantom Chemical (Quan)
tum Chemical Corporation
) can be suitably used.

The thickness of the base material layer and the adhesive layer may be appropriately determined depending on the application, but the thickness of the base film is generally 10 to 80 mm.
The thickness of the adhesive layer is generally 5 to 30 μm.
It is about μm.

In addition, a softener, an ultraviolet absorber, an antioxidant, etc. may be added to the adhesive layer, and a light stabilizer, an ultraviolet absorber, an antioxidant, etc. may be added to the base material layer as necessary.

The surface protection film of the present invention can be generally produced by coextruding materials forming the base layer and the adhesive layer by an inflation method, a T-die method, or other methods.

[For Use] The adhesive layer of the surface protection film of the present invention is made of an ethylene-n-butyl acrylate copolymer, and due to the molecular structure of the copolymer, it has excellent heat resistance and weather resistance. The copolymer also has good melt extrusion properties and is suitable for coextrusion with polyolefin resins.

[Examples] The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Example 1] Medium-density polyethylene (trade name: "Neozex 3510FJ, manufactured by Mitsui Petrochemical Industries, Ltd.") was used as a base material layer with a thickness of 70 μm, and an ethylene-n-butyl acrylate copolymer (trade name: rEnathaeneEA 720-0) was used as an adhesive layer.
09J Quantum Chemical Corp
oration n-butyl acrylic notebook content = 2
0%, MI=6.0) to a thickness of 10 μm using a T-die method to obtain a surface protection film.

[Comparative Example 1] Medium density polyethylene (trade name [Neozex 3510FJ, manufactured by Mitsui Petrochemical Industries, Ltd.) was used as the base material layer with a thickness of 70 μm, and ethylene vinyl acetate copolymer (vinyl acetate content 28%) was used as the adhesive layer. A surface protection film was obtained by coextrusion using a T-die method to a thickness of 10 μm.

The results of Example 1 and Comparative Example 1 are shown in Table 1.

The physical properties were measured as follows.

<Initial adhesion strength> Two surface protective films are attached to the acrylic board using a laminator, and after 30 minutes at 23°C, 300mm
The force required when peeling off at an angle of 180° at a speed of /min is expressed as a value converted to a width of 50 mm.

<Adhesion strength over time>: The surface protection film was attached to an acrylic board using a laminator, and after curing for 60 days at 23°C,
The force required when peeling off at an angle of 180° at a speed of mm/min is expressed in terms of g/50 mm width.

Heat-resistant adhesive strength〉The two-surface protective film was attached to the acrylic board using a laminator, and after curing at 60℃ for 10 days,
The force required when peeling off at an angle of 180° at a speed of mm/min is expressed in terms of g/50 mm width.

<Weather-resistant adhesive strength>: After conducting a test for 120 hours using an accelerated exposure tester WS type (using a sunshine carbon arc lamp) specified in JIS A1415,
The force required when peeling off at an angle of 180° at a speed of 300 mm/min is expressed in terms of g/50 mm width.

(The following is a blank space) Table 1 [Effects of the Invention 1 According to the present invention, the present invention has good adhesion (temporary adhesion) and little increase in adhesion over time or at high temperatures (in addition, it has excellent weather resistance). A surface protection film is provided with good moldability.

Claims (1)

[Claims] (1) A surface protection film comprising a base layer made of a polyolefin resin and an adhesive layer made of an ethylene-n-butyl acrylate copolymer.