JPH10102014A5 - - Google Patents

Description

[0001]
[Technical Field to which the Invention Belongs]
The present invention relates to an adhesive laminate comprising a substrate layer and an adhesive layer formed on one side of the substrate layer, the adhesive layer having good adhesion to metal surfaces, glass surfaces, painted surfaces, etc. and good releasability.

[0002]
2. Description of the Related Art
Conventionally, acrylic adhesives and rubber-based adhesives mainly made of rubber such as natural rubber and polyisobutylene have been widely used as adhesives for adhesive laminates . These adhesives often require the use of solvents during production, which poses problems such as fire hazards and pollution during production, as well as economical issues due to the large number of manufacturing steps.
In recent years, in order to solve such problems, a method has been used in which a hot-melt adhesive is used to produce an adhesive laminate by co-extrusion molding a base layer and an adhesive layer.
An example of an adhesive laminate produced by coextrusion is a surface protection film. Surface protection films are used to prevent the surfaces of coated and painted steel plates, metal plates, synthetic resin plates, glass plates, decorative panels, etc. from being scratched or soiled during processing and transportation. Surface protection films have a structure in which an adhesive layer is formed on one side of a substrate layer made of thermoplastic resin or paper, and must have appropriate adhesion to the adherend and good releasability, i.e., be able to be easily peeled off after use without contaminating the surface of various adherends with the adhesive.
Known examples of this type of surface protection film include a substrate layer made of a polyolefin resin and a pressure-sensitive adhesive layer formed on one side thereof using an ethylene-based adhesive, such as EVA, but these films do not adhere well to the adherend unless a tackifier resin is used in combination. Furthermore, when the film is left attached to the adherend for a long period of time, the adhesive strength increases, making it difficult to obtain sufficient releasability.

[0004]
[Means for solving the problem]
That is, the present invention provides an adhesive laminate comprising a base layer (A) and an adhesive layer (B) formed on one side of the base layer, characterized in that the adhesive layer (B) contains at least one kind of vinyl aromatic compound polymer block (A), a random copolymer block of a vinyl aromatic compound and a conjugated diene compound or a conjugated diene compound polymer block (B), and a hydrogenated diene copolymer ( 1 ) obtained by hydrogenating the conjugated diene portion of a block copolymer comprising a polybutadiene block (C) containing 30% by weight or less of butadiene units having 1,2-vinyl bonds.

[0008]
The hydrogenated diene copolymer (1) of the present invention is obtained by hydrogenating the conjugated diene portion of a block copolymer consisting of blocks (A), (B), and (C), which will be described in detail below, and the hydrogenation rate is preferably 80% or more. If the hydrogenation rate is less than 80%, the heat resistance and weather resistance of the composition will be inferior, which is undesirable.
The (A) block is a vinyl aromatic compound polymer, preferably a polystyrene block. The (A) block content of the (1) hydrogenated diene copolymer is preferably 2 to 20% by weight, more preferably 2 to 10% by weight. If it exceeds 20% by weight, the adhesiveness tends to be poor, which is not preferred.
The (B) block is a random copolymer of a vinyl aromatic compound and a conjugated diene compound , or a conjugated diene compound polymer. The random copolymer of a vinyl aromatic compound and a conjugated diene compound is preferably a copolymer of butadiene and styrene, a copolymer of isoprene and styrene, or a copolymer of butadiene, isoprene, and styrene. The conjugated diene compound polymer is preferably a butadiene polymer, an isoprene polymer, or a copolymer of butadiene and isoprene. The content of the (B) block in the (1) component is preferably 30 to 90% by weight.
The (C) block is a polybutadiene containing 30% by weight or less of butadiene units having 1,2- vinyl bonds. If the butadiene units having 1,2- vinyl bonds exceed 30% by weight, the adhesiveness becomes poor, which is undesirable. The content of the (C) block in the (1) component is preferably 2 to 50% by weight, more preferably 10 to 40% by weight. If it exceeds 50% by weight, the adhesiveness tends to become poor, which is undesirable.
Furthermore, the blocks (A), (B), and (C) are preferably bonded in the order of (A), (B), and (C) in a block form.

[0013]
[Example]
The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples as long as it does not depart from the gist of the invention.
Various evaluations in the examples and comparative examples were carried out as follows.
Amount of vinyl aromatic compound bound (wt%)
It was measured by infrared analysis using the absorption of the phenyl group at 679 cm ^-1 .
1,2-vinyl bond content of conjugated diene moiety (%)
Infrared analysis was used and calculation was performed by the Hampton method.
Hydrogenation rate (%)
Ethylene tetrachloride was used as a solvent and the calculation was carried out by 1H-NMR spectroscopy at 100 MHz.
Number average molecular weight of hydrogenated diene copolymer : Calculated in terms of polystyrene by gel permeation chromatography (GPC) at 135°C using trichlorobenzene as a solvent.
Molding processability : An adhesive laminate was molded and visually evaluated.
Good: No uneven thickness or rough surface, and good molding processability. Poor: Poor molding processability due to uneven thickness and rough surface.
Adhesion <br/>Adhesion to painted surfaces, stainless steel plates, and glass plates was evaluated.
○: Good adhesion ×: Poor adhesion
Removability The samples evaluated for adhesion were also evaluated for removability.
○; Good re-peelability ×; Poor re-peelability
The surface of the adherend was visually evaluated after peeling .
◯: No trace of application x: Trace of application The components used in the formulations of the Examples and Comparative Examples are as follows.

[0015]
[Table 1]

[0019]
[Effects of the Invention]
The adhesive laminate of the present invention can be produced by extrusion molding, has excellent weather resistance and moldability, has appropriate adhesive strength, and good releasability , and is usable for surface protection films to prevent scratches on steel plates, painted steel plates, decorative steel plates, glass plates, resin plates, etc., adhesive tapes, adhesive labels, adhesive sheets, assemblies , etc., and is of great industrial value.

Claims (6)

An adhesive laminate comprising a base layer (a) and an adhesive layer (b) formed on one side of the base layer,
The pressure-sensitive adhesive layer (ii) comprises at least one of a vinyl aromatic compound polymer block (A), a random copolymer block of a vinyl aromatic compound and a conjugated diene compound or a conjugated diene compound polymer block (B), and a polybutadiene block (C) containing 30% by weight or less of butadiene units having 1,2- vinyl bonds. 2. The adhesive laminate according to claim 1, wherein the adhesive layer (b) comprises 50 to 100% by weight of the hydrogenated diene copolymer (1) and 0 to 50% by weight of the olefin resin (2). 3. The adhesive laminate according to claim 1, wherein the hydrogenated diene copolymer (1) comprises 2 to 20% by weight of the block (A), 30 to 90% by weight of the block (B), and 2 to 50% by weight of the block (C). 4. The adhesive laminate according to claim 1, wherein the substrate layer (a) is made of a thermoplastic resin, paper, or a foam. The adhesive laminate according to any one of claims 1 to 4, wherein the adhesive laminate has a thickness of 10 µm or more. 6. The adhesive laminate according to claim 1, wherein the base layer (a) and the adhesive layer (b) are laminated by extrusion molding.