JPH07116410B2 - Adhesive film for surface protection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is such that the surface of a plate-like article such as a metal plate, a glass plate, a synthetic resin plate or the like is releasably adhered to the article so that the surface of the article may be damaged. The present invention relates to an adhesive film for surface protection which prevents dust and the like from adhering. More specifically, the present invention relates to an adhesive film for surface protection which is adhered to a plate-like article and has little change with time in adhesive strength even when left for a relatively long time, and which can maintain an adhesive strength that can be easily peeled and removed at all times. .

[Prior art]

Conventionally, as a pressure-sensitive adhesive for an adhesive film for surface protection, an acrylic pressure-sensitive adhesive, a natural rubber, a rubber-based pressure-sensitive adhesive mainly composed of rubber such as polyisobutylene has been widely used, but these are solvent-based. Therefore, there are problems in safety and hygiene, pollution, economy, etc. during the production of the surface protection adhesive film. In recent years, solvent-free adhesives have been demanded in order to improve these problems, and as one of the effective means, a method of producing an adhesive layer and a support film (polyolefin resin film) by coextrusion Are being studied. However, in this manufacturing method by co-extrusion, polyethylene, which is a representative of difficult-to-adhesive materials, corona treatment, which is a powerful means for increasing the adhesiveness (anchoring property) between an olefin resin film such as polypropylene and polypropylene and an adhesive layer, Since alkali treatment, flame treatment, etc. cannot be performed, it is extremely difficult to obtain a coextruded film having good anchoring properties. Therefore, when the film is temporarily attached to a metal plate or the like and subjected to sheet metal processing, the anchoring force is small, so that there is a problem that interface destruction occurs between the support layer film and the adhesive layer, and adhesive residue occurs. .

In order to solve this problem, a copolymer containing ethylene as a main component, which has a high affinity with a polyolefin resin film, for example, a coextrusion film having EVA as an adhesive layer has been proposed. Those having an extremely low value can obtain sufficient anchoring force, but have a problem in that they have almost no tackiness and cannot be highly adhered. On the other hand, coextrusion of a block polymer such as SBB.SIS and a polyolefin resin film has been proposed, and although these systems have relatively excellent anchoring power, they tend to deteriorate when stored for a long period of time, and the pseudo-aggregation force tends to occur. However, there is a problem that adhesive residue is generated due to the decrease in the adhesiveness, and in any case, no satisfactory adhesive residue is found.

[Problems to be solved by the invention]

An object of the present invention is to provide a surface protective film that has an excellent anchoring force, does not cause adhesive residue even after long-term storage, and can be manufactured by coextrusion.

[Means for solving problems]

The present inventors have studied various materials in order to solve the above-mentioned difficult problems, and as a result, A-B-A (however, A
Is a styrene polymer block, B is a polymer block of ethylene and butylene) as a main component, and an adhesive layer is formed on the polyolefin resin film by adding a tackifying resin in a specific amount or less. The present invention has been completed by finding that the adhesive film for surface protection formed as described above can solve the above object. That is, the present invention provides an adhesive layer comprising a composition containing 100 parts by weight of the general formula, A-B-A (where A and B have the same meanings as described above), and 0 to 80 parts by weight of a tackifying resin. Is formed on a polyolefin resin film, and is formed of an adhesive film for surface protection.

A in A-B-A used in the present invention is a styrene polymer block whose preferred molecular weight is 2000-
It is about 100000, and its preferable glass transition temperature is 20 ° C. or higher. Also, B in A-B-A is
Although it is a copolymer block of ethylene and butylene, its preferred molecular weight is about 10,000 to 300,000, and its preferred glass transition temperature is -20 ° C or lower. The preferred weight ratio of A and B is A / B = 5/95 to 50/50.
Preferable examples of ABA include Kraton G-1650 and Kraton G-1652 manufactured by Shell Chemical Co., Ltd.

In the present invention, in addition to A-B-A, further A-B
You may mix | blend.

The definitions of A and B in AB are the same as above,
The weight ratio of A and B is preferably A / B = 5/95 to 50/50. A-
As an example of the mixture of BA and AB, for example, Shel
Examples include Kraton G-1657 manufactured by Kagaku.

As the tackifying resin used in the present invention, various resins can be used depending on the purpose, but generally,
A material having a good compatibility and a property capable of improving the adhesive strength is used. Specifically, for example, phenol resin, rosin, pinene resin, petroleum resin, styrene resin, coumarone resin and the like are suitable. The addition amount is A-B-A (A-
(Including B-A and A-B mixture) 0 to 8 per 100 parts by weight
The amount is 0 part by weight, preferably 20 to 60 parts by weight. If the tackifying resin exceeds 80 parts by weight, the adhesive strength after a long-term sticking will remarkably increase, and adhesive residue tends to occur during peeling.

The polyolefin resin film used in the present invention is preferably composed of a material that can be melt-extruded to serve as a support for the surface protection film. As an example of such a material, a material made of polyethylene, polypropylene or the like is preferable in terms of cost.

For the adhesive layer, various materials such as various rubbers, softeners, fillers, ultraviolet absorbers, and antioxidants that are commonly used may be used according to the purpose within the range not departing from the gist of the present invention. .

The thickness of each layer of the adhesive film for surface protection of the present invention is preferably as follows. That is, the adhesive layer is preferably
200μ or less, more preferably 5 to 50μ, the polyolefin resin film layer is 300μ or less, preferably 10 to 1
It is 00μ.

The surface protective adhesive film of the present invention is produced, for example, as follows. That is, the adhesive component and the thermoplastic synthetic resin are made into two streams by a melt co-extrusion device, that is, the support film forming fluid and the adhesive layer forming fluid are combined in a die opening to form a single stream. It is manufactured by forming one fluid, extruding, and compounding the adhesive layer and the polyolefin resin film layer. Of course, it can be easily produced by applying the adhesive layer constituent composition to the polyolefin resin film.

[Action / effect]

The surface protective film obtained by the method of the present invention is excellent in anchoring force to the polyolefin resin film of the adhesive layer, and is temporarily attached to the surface protective film metal plate or the like for sheet metal processing, or may be left as it is for a long time. However, it has a remarkable characteristic that adhesive residue does not occur. More specifically, as is clear from the experimental examples described below, the surface protective adhesive film of the present invention has an anchoring force of 2000 g / 20 mm or more,
No glue residue is observed after processing. Further, even when the pieces are laminated and stored for a long period of time, the adhesive layer is hardly deteriorated, and no adhesive residue is observed at all, which is a remarkable effect.

[Examples and experimental examples]

Examples of the present invention will be shown below, but the present invention is not limited to these examples. Examples 1-3
Comparative Examples 1-2 Using the adhesive components and polyolefin resin (for forming polyolefin resin) shown in Table 1, under the conditions shown in Table 1, adhesive films for surface protection having the respective layer thicknesses shown in Table 1 were prepared. Obtained.

Experimental Example 1 Anchoring force of each surface protection adhesive film obtained above,
Examine the adhesive residue after pasting, adhesive strength and adhesive residue after processing,
The results are shown in Table 1.

Evaluation method in Table 1 Anchoring force: Measured by performing a 180 degree peeling test in 20 ° C x 65% relative humidity (RH) after storing the sample pieces for one hour after bonding them to each other with glue surfaces .

The peeling speed is 300 mm / min.

Adhesion: A sample piece was attached to a SUS304 stainless steel plate, and a 180 degree peeling test was performed to measure. Peeling speed is 30
It is 0 mm / min.

Adhesive residue after application: A sample piece was attached to a SUS304 stainless steel plate, left at 40 ° C for 6 months, and then observed for adhesive residue at 20 ° C x 65% relative humidity (RH).

Adhesive residue after processing: Stick a sample piece on a SUS304 stainless steel plate with a thickness of 0.4 mm, set it in the mold so that the sample piece will be on the die side, and squeeze it to a depth of 20 mm with a punch of 50 mmΦ Stainless steel plate The adhesive residue on the surface was observed.

Claims (1)

[Claims] 1. ABA containing 100 parts by weight (where A is a styrene polymer block and B is a copolymer block of ethylene and butylene) and 0 to 80 parts by weight of a tackifying resin. An adhesive film for surface protection, which is formed by forming an adhesive layer made of the composition described above on a polyolefin resin film.