JPH0762301A - Pressure-sensitive adhesive film - Google Patents

Abstract

PURPOSE:To improve the adhesion of a pressure-sensitive adhesive composed mainly of a polyisobutylene homopolymer or a butyl rubber obtained by copolymerizing a polyisobutylene with a small amount of isoprene to a support having high polarity and comprising, e.g. a flexible vinyl chloride resin. CONSTITUTION:This film consists of: a support comprising a flexible vinyl chloride resin film; an undercoating layer formed on the support and consisting of 0.1-10 pts.wt. cross-linking agent and 100 pts.wt. composition of 90-5wt.% ethylene/vinyl acetate copolymer and 10-95wt.% reactive ethylene/vinyl acetate copolymer having 0.1-10wt.% functional groups; and a pressure-sensitive adhesive layer formed on the undercoating layer and composed mainly of a polyisobutylene or butyl rubber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive film having improved adhesion between an adhesive containing polyisobutylene or butyl rubber as a main component and a support made of a soft vinyl chloride resin film.

[0002]

2. Description of the Related Art Metal plates such as aluminum and stainless steel,
In order to protect the surfaces of acrylic, polycarbonate and other resin plates, glass plates and their coated plates from scratches, stains, etc. during processing, transportation and storage,
An adhesive film is used in which a soft vinyl chloride-based or polyolefin-based resin film is used as a support and an adhesive is provided on one surface thereof.

[0003] Among them, an adhesive film having a soft vinyl chloride resin film as a support has excellent curved surface followability, so that it is an adherend such as a flexible film or sheet, or a surface with irregularities or irregularities. Widely used for wearing. Examples of the pressure-sensitive adhesive used in the pressure-sensitive adhesive film having such a soft vinyl chloride resin film as a support include acrylic acid ester copolymers and pressure-sensitive adhesives containing natural rubber as a main component.

The pressure-sensitive adhesive containing an acrylic acid ester copolymer as a main component contains a large amount of low molecular weight substances such as an organic solvent and a plasticizer, which has a large polarity and therefore has a large increase in the adhesive force with time after sticking the pressure-sensitive adhesive film. When it is attached to an adherend, the cohesive force of the pressure-sensitive adhesive decreases due to the low molecular weight substance, and when the adhesive film is peeled from the adherend, there is a problem that adhesive remains.

A pressure-sensitive adhesive containing natural rubber as a main component is also mixed with a tackifier for imparting tackiness due to its constitution, and therefore it is applied to an adherend containing a large amount of low molecular weight substances such as organic solvents and plasticizers. If it is attached, there will be a problem such as adhesive residue.

Therefore, a pressure sensitive adhesive containing butyl rubber as a main component, which is obtained by copolymerizing a small amount of polyisobutylene or polyisobutylene with isoprene, has been used. Polyisobutylene simple substance or a pressure-sensitive adhesive containing butyl rubber as a main component obtained by copolymerizing a small amount of isoprene with polyisobutylene has extremely low polarity in its molecular structure, so that there is little change with time in the adhesive force after sticking an adhesive film, Even when it is attached to an adherend containing a large amount of low-molecular weight substances such as organic solvents and plasticizers, the low-molecular weight substances are hardly transferred to the pressure-sensitive adhesive, and the suspicion power is unlikely to decrease.

[0007]

However, a pressure-sensitive adhesive containing butyl rubber as a main component, which is obtained by copolymerizing polyisobutylene alone or a small amount of polyisobutylene with isoprene, is
Poor adhesion to highly polar supports such as soft vinyl chloride resins. The present invention improves the adhesion between a polyisobutylene simple substance or a pressure sensitive adhesive containing butyl rubber as a main component obtained by copolymerizing polyisobutylene with isoprene in a small amount, and a highly polar support such as a soft vinyl chloride resin. The purpose is to

[0008]

That is, the present invention provides a support comprising a soft vinyl chloride resin film with 0.1 to 20 parts.
Crosslinking agent 0.1 to 100 parts by weight of a mixture of 10 to 95% by weight of a reactive ethylene-vinyl acetate copolymer having 90% by weight of a functional group and 90 to 5% by weight of an ethylene-vinyl acetate copolymer. The present invention relates to an adhesive film formed by forming an undercoat layer containing 10 parts by weight and an adhesive layer containing polyisobutylene or butyl rubber as a main component.

The soft vinyl chloride resin film used as a support is a vinyl chloride resin film containing a plasticizer that imparts flexibility, a film of a resin copolymerized with vinyl chloride and a component that imparts plasticity, or a chloride. An example of the resin film is a blend of a vinyl resin and another resin. The thickness of the support is not particularly limited, but is about 50-
It is preferably 300 μm. When it is necessary to impart or improve weather resistance, heat resistance, processability and workability to the support, an antioxidant, an ultraviolet absorber, a lubricant and the like are added as necessary.

The plasticizer is not particularly limited, and examples thereof include diethyl phthalate, dibutyl phthalate,
Dioctyl phthalate, phthalates such as di-2-ethylhexyl phthalate, sebacates such as di-2-ethylhexyl sebacate, dibutyl sebacate, di-2-ethylhexyl azelate, diisooctyl azelate, Of azelaic acid esters such as dibutyl azelate, tri- (2-ethylhexyl) trimellitate, trimellitic acid esters such as triisodecyl trimellitate, di- (2-ethylhexyl) adipate, diisodecyl adipate, dibutyl adipate Adipates, tricresyl phosphate, phosphates such as trixylenyl phosphate, epoxidized soybean oil, epoxidized castor oil, epoxidized fatty acid esters such as epoxidized linseed oil, Shin acid, azelaic acid, polyesters of phthalic acid, liquid urethane resins.

Polyisobutylene used as the main component of the pressure-sensitive adhesive is a polymer of isobutylene, and butyl rubber is a copolymer of isobutylene and isoprene. It may be a copolymerized, chlorinated or brominated monomer having a functional group such as a carboxylic acid group or a hydroxyl group. Further, a tackifier, an antioxidant, an ultraviolet absorber or the like may be added to improve the tackiness, weather resistance and the like.

The ethylene-vinyl acetate copolymer having a functional group used in the undercoating agent is a monomer having a functional group which reacts with a crosslinking agent when copolymerizing ethylene and vinyl acetate. The copolymer obtained by adding 0.1 to 20% by weight and copolymerizing it, or the one obtained by chemically introducing a functional group that reacts with a crosslinking agent into an ethylene-ethyl acetate copolymer, etc. Can be mentioned.

This functional group is added to the copolymer for the purpose of improving the pseudo-collecting power of the undercoating agent itself by reacting with the crosslinking agent and ensuring high adhesion to the support. Therefore, when the amount of the functional group is less than 0.1% by weight, the pseudo-collecting force of the undercoating agent and the adhesion with the support are deteriorated, and the content of 20% by weight is increased.
If it exceeds, the polarity of the undercoating agent becomes high and the adhesive strength with the adhesive is lowered.

As this functional group,

[Chemical 2] Such a functional group is preferably used. Especially good reactivity with isocyanate compounds,

[Chemical 3] Such functional groups are more preferably used.

The content of vinyl acetate in each of the ethylene-vinyl acetate copolymer and the reactive ethylene-vinyl acetate copolymer is preferably 5 to 50% by weight. If the amount is less than 5% by weight, the adhesive force between the support and the undercoating agent is lowered, and the workability is lowered due to the high crystallinity, and if it exceeds 50% by weight, the adhesive force between the adhesive agent and the undercoating agent is lowered.

The undercoating agent is composed of 10-95% by weight of a reactive ethylene-vinyl acetate copolymer having a functional group and ethylene-
Used in a mixed system with 90 to 5% by weight of vinyl acetate copolymer. When the content of the reactive ethylene-vinyl acetate copolymer having a functional group is less than 10% by weight, the adhesion between the support and the undercoating agent is lowered. Further, if the ethylene-vinyl acetate copolymer is less than 5% by weight, the adhesive strength between the pressure-sensitive adhesive and the undercoating agent is lowered.

Examples of the crosslinking agent added to the undercoating agent include sulfur compounds, peroxides, metal oxides, polyfunctional amines, quinone dioximes, methylol resins, chlorine compounds, azo compounds, isocyanate compounds, organosilicon compounds and the like. To be A highly reactive polyfunctional isocyanate compound is preferably used, and a trifunctional aromatic isocyanate compound is more preferably used.

The amount of the cross-linking agent added to the undercoating agent is 0.1 to 10 parts by weight based on 100 parts by weight of the blend of the reactive ethylene-vinyl acetate copolymer having a functional group and the ethylene-vinyl acetate copolymer. Used in the department. If the amount of the cross-linking agent added is less than 0.1 part by weight, the cohesive force of the undercoating agent will be lowered, and if it exceeds 10 parts by weight, the adhesion between the undercoating agent and the support will be lowered.

[0019]

The technical point of the pressure-sensitive adhesive film of the present invention is to develop a remarkable adhesive force between the pressure-sensitive adhesive containing polyisobutylene or butyl rubber as a main component and the soft vinyl chloride resin film. For this purpose, 0.1 part of a cross-linking agent is added to 100 parts by weight of a mixture composed of 10 to 95% by weight of a reactive ethylene-vinyl acetate copolymer having a functional group and 90 to 5% by weight of an ethylene-vinyl acetate copolymer. Sufficient adhesion can be obtained by using an undercoating agent containing 10 to 10 parts by weight. The undercoating agent layer has a functional group and thus has a good affinity with the soft vinyl chloride resin, and since it has a polyethylene skeleton, it has a good affinity with the adhesive agent.

Adhesives containing polyisobutylene or butyl rubber as a main component have good properties such that the adhesive strength is unlikely to increase due to their low polarity and chemically stable structure, and that they are less susceptible to low molecular weight substances such as solvents and plasticizers. However, because of this, the adhesiveness with the highly polar vinyl chloride resin film was poor and it could not be utilized.

[0021]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Example 50 parts of ethylene-vinyl acetate copolymer (EV-45X manufactured by Mitsui DuPont Polychemical Co., Ltd., VA% = 45),
50 parts reactive ethylene-vinyl acetate copolymer (HPR VR-105 maleic anhydride 1% modified by DuPont Mitsui Polychemical Co., Ltd., VA% = 46) 50 parts trifunctional aromatic isocyanate (Coronate L manufactured by Nippon Polyurethane Co., Ltd.) An undercoat solution consisting of a 1 wt% toluene solution of a composition consisting of 1 part was applied to a soft vinyl chloride resin film containing 40 wt% of DOP (dioctyl phthalate) having a thickness of 100 μm and a thickness after drying of 0.1 μm. To form an undercoat layer, and polyisobutylene (Vitanex MM manufactured by Tonex Co., Ltd.
L-100) was applied to a thickness of 5 μm to prepare an adhesive film.

Comparative Example 1 A film was prepared in the same manner as in Example 1 except that the undercoating agent was not used.

Comparative Example 2 An ethylene-vinyl acetate copolymer (EV-550 manufactured by Mitsui DuPont Polychemical Co., Ltd., VA% = 2) was used as an undercoating agent.
It was prepared in the same manner as in Example except that the undercoating agent solution consisting of 1% by weight toluene solution of 8) was used.

Comparative Example 3 An adhesive film was prepared in the same manner as in Example 1 except that the trifunctional isocyanate compound added to the undercoating agent was omitted.

Comparative Example 4 85 parts of butyl acrylate, 10 parts of acrylonitrile,
Acrylic ester copolymer 100 obtained by pearl polymerization of 5 parts of hydroxyethyl methacrylate in the presence of a catalyst
To 3 parts of a trifunctional aromatic isocyanate (Coronate L manufactured by Nippon Polyurethane Co., Ltd.),
DOP (dioctyl phthalate) 40 with a thickness of 100 μm
A soft vinyl chloride resin film containing 5 parts by weight has a thickness of 5
An adhesive film was prepared by coating and drying so that the thickness became μm.

Polyester resin ink was screen-printed on a soft vinyl chloride resin sheet, dried at 45 ° C. for 90 minutes and left at room temperature for 12 hours, and then the adhesive films obtained in Examples and Comparative Examples were rolled. Pasted in. Then, peeling was performed at a peeling speed of 200 mm / min and a peeling angle of 90 degrees, and the resistance value at this time was measured. The results are shown in Table 1. In the table, the initial adhesive strength is 3 after sticking the adhesive film.
The adhesive strength after being left at room temperature for 0 minutes and after aging is measured after the test piece to which the adhesive film is attached is kept at 80 ° C. for 24 hours and then left at room temperature for 30 minutes.

[0027]

[Table 1]

According to the present invention, the adhesion between a pressure sensitive adhesive containing polyisobutylene or butyl rubber as a main component and a support such as a highly polar vinyl chloride resin film is improved, and solvent resistance and plasticizer resistance are improved. It is possible to obtain a pressure-sensitive adhesive film that is excellent in properties and curved surface followability, and that makes use of the characteristics of a pressure-sensitive adhesive containing polyisobutylene or butyl rubber as a main component.

Claims (4)

[Claims] 1. A support comprising a soft vinyl chloride resin film, and a reactive ethylene-vinyl acetate copolymer 10 formed on the support and having 0.1 to 10% by weight of a functional group.
~ 95 wt% and ethylene-vinyl acetate copolymer 90-5
The cross-linking agent is added to 100 parts by weight of the compound consisting of 0.1% by weight.
An adhesive film comprising an undercoat layer consisting of 1 to 10 parts by weight, and an adhesive layer formed on the undercoat layer and containing polyisobutylene or butyl rubber as a main component. 2. The pressure-sensitive adhesive film according to claim 1, wherein the crosslinking agent is a polyfunctional isocyanate. 3. The functional group of the reactive ethylene-vinyl acetate copolymer is represented by: The pressure-sensitive adhesive film according to claim 1 or 2. 4. The pressure-sensitive adhesive film according to claim 1, 2 or 3, wherein the reactive ethylene-vinyl acetate copolymer and the ethylene-vinyl acetate copolymer having a functional group have a vinyl acetate content of 5 to 50% by weight. .