JP2000345124A - Production of adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an adhesive sheet having excellent adhesivity between an olefinic substrate and an adhesive mass layer, capable of simplifying facilities and improving production efficiency by omitting a part of a conventional production processes. SOLUTION: An adhesive mass comprising an olefinic resin and an uncrosslinked thermoplastic resin is co-extrusion molded to one side of a release paper so that the adhesive mass exists at the release paper side and a colored coating film is laminated to the surface of the olefinic resin layer. An olefinic substrate resin having cutting properties, flexibility and strength required for a marking sheet can be used as the olefinic substrate resin. For example, a polyethylene, a polypropylene, a copolymer of ethylene and propylene, or the like, may be cited as the resin. Especially, a polyethylene and a polypropylene having the same flexibility as that of vinyl chloride resin and low crystallizability and a blend of a copolymer of propylene and ethylene having excellent stress relaxation as that of vinyl chloride are preferable as the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pressure-sensitive adhesive sheet used for outdoor and indoor advertisements and display stickers.

[0002]

2. Description of the Related Art As a signboard or an advertisement used outdoors or the like, a marking sheet is used in which an adhesive sheet made of a colored vinyl chloride resin sheet as a base material is cut out into a pattern or character instead of the conventional painting, and is pasted. . Many of such pressure-sensitive adhesive sheets are manufactured by casting a colored vinyl chloride resin sol on process paper, or forming a sheet by calendering, and laminating a pressure-sensitive adhesive layer and release paper on the sheet.

[0003] To prepare a sheet by casting a vinyl chloride resin sol, a step of drying and curing the cast sol and a step of laminating an adhesive layer are required. Is required.
In recent years, awareness of environmental problems caused by disposal after use has increased, and there has been a demand for dechlorination.

Therefore, as an alternative to the vinyl chloride resin as the base material, the applicant has proposed a pressure-sensitive adhesive sheet in which an ink-receiving layer is laminated on one surface of an olefin-based resin substrate sheet and a pressure-sensitive adhesive layer is laminated on the other surface. . This pressure-sensitive adhesive sheet is obtained by extruding an olefin-based resin with a T-die to produce a sheet, and separately applying an acrylic pressure-sensitive adhesive solution to release paper and drying, and laminating the pressure-sensitive adhesive layer formed on the sheet. is there.

[0005] However, the production of this pressure-sensitive adhesive sheet requires a process of once forming the sheet and then laminating the formed pressure-sensitive adhesive layer, and there is a problem that the equipment becomes large and the production efficiency is low. Furthermore, since the olefin resin has low polarity, it has poor adhesion to the pressure-sensitive adhesive layer, and there is a problem that peeling from the pressure-sensitive adhesive layer often occurs.

[0006]

SUMMARY OF THE INVENTION The present invention simplifies equipment and improves production efficiency by omitting a part of the conventional manufacturing process, and achieves excellent adhesion between an olefin-based substrate and an adhesive layer. An object of the present invention is to provide a method for producing an adhesive sheet.

[0007]

The method for producing a pressure-sensitive adhesive sheet according to the present invention is characterized in that an olefin-based resin and a pressure-sensitive adhesive made of an uncrosslinked thermoplastic resin are mixed with a release paper so that the pressure-sensitive adhesive is on the release paper side. After co-extrusion molding on one side, a colored coating film is laminated on the surface of the olefin-based resin layer.

The olefin base resin used in the present invention may be any resin having cutting properties, flexibility and strength required for a marking sheet.
Examples include polyethylene, polypropylene, and a copolymer of ethylene and propylene. In particular, polyethylene or polypropylene having low flexibility and similar flexibility to vinyl chloride, and a blend of a copolymer of propylene and ethylene having excellent stress relaxation properties such as vinyl chloride are preferable.

The uncrosslinked thermoplastic resin is not particularly limited as long as it has adhesiveness by itself and has a fluidity capable of being extruded by an extruder. However, in view of the required weather resistance and adhesive properties, Adhesive materials such as rubber and acrylics from which double bonds have been removed by hydrogenation, such as SEBS, are preferred.

[0010] By co-extrusion of an olefin resin and an uncrosslinked thermoplastic resin, it is possible to obtain a laminate in which both are firmly adhered.

The release paper may be any paper as long as it has stable releasability from the thermoplastic resin, and may be coated paper, polyethylene laminated paper, PET film or the like coated with a silicone resin or a fluorine resin.

[0012] The paint is used to exhibit the function of the marking sheet, and has good adhesion to the surface of the olefin resin as the base material. Examples of such paints include acrylic, urethane, melamine, and polyester one-component types that form a film by drying and curing, and two-component curable types. Commonly used paints can be used.

In order to uniformly apply the paint to the surface of the olefin resin layer as the base material, it is preferable to use a solvent-based paint having good wettability with the base material surface. For applications requiring weather resistance, acrylic urethane-based or melamine-based paints such as those used for automobiles and building materials are preferred. When higher weather resistance is required, it is preferable to use an inorganic fired pigment, a silicone-based, or a fluorine-based resin.

In order to improve the adhesion between the paint and the olefin-based resin substrate, it is preferable to subject the substrate surface to a corona discharge treatment, a flame treatment, a base treatment with chlorinated polypropylene or the like. Any method such as spray coating and roll coating can be adopted.

[0015]

Embodiments of the present invention will be described below. Example 1 20 parts by weight of a rutile-type titanium oxide masterbatch (containing 60% by weight of a pigment) as a white pigment was mixed with 100 parts by weight of a low-density polyethylene (manufactured by Mitsubishi Chemical Corporation, trade name "LC500") as an olefin resin. did. As an uncrosslinked thermoplastic resin, 50 parts by weight of a tackifier resin (trade name "Alcon P70", manufactured by Arakawa Chemical Co., Ltd.) was blended with 100 parts by weight of SEBS (trade name "Toughtec" manufactured by Asahi Kasei Corporation). The low-density polyethylene and the thermoplastic resin are co-extruded with a two-layer co-extrusion molding machine from a T-die so that the polyethylene layer has a thickness of 60 μm and the thermoplastic resin layer has a thickness of 25 μm. It was laminated on the above release paper, and was once wound up. Next, a corona discharge treatment was applied to the surface of the polyethylene layer, and 100 parts by weight of an acrylic paint (trade name "Auto V Top Monarch Blue" manufactured by Dainippon Paint Co., Ltd.) was added to an isocyanate-based curing agent (trade name "Coronate 2094" manufactured by Nippon Polyurethane Co., Ltd.) "1
0 part by weight)) was applied and cured to form a coating layer.

Comparative Example 1 The same low-density polyethylene as that used in Example 1 was extruded from a T-die to a thickness of 60
μm polyethylene sheet. 100 parts by weight of SEBS (trade name "Toughtec" manufactured by Asahi Kasei Corporation) and 50 parts by weight of tackifying resin (trade name "Alcon P70" manufactured by Arakawa Chemical Co., Ltd.) are dissolved in 850 parts by weight of toluene and coated on a release paper. It dried and the adhesive layer was formed. One surface of the polyethylene sheet was subjected to corona discharge treatment, and the pressure-sensitive adhesive layer was laminated on the treated surface and wound up. Further, the other surface of the polyethylene sheet was subjected to a corona discharge treatment, and the same acrylic paint as in Example 1 was applied to this surface and cured to form a coating layer.

Comparative Example 2 The toluene solution of the pressure-sensitive adhesive used in Comparative Example 1 was directly applied to the surface of the polyethylene sheet on which the pressure-sensitive adhesive layer was laminated without performing corona discharge treatment, and dried. As a result, wrinkles occurred and no pressure-sensitive adhesive sheet was obtained.

Comparative Example 3 An adhesive sheet having a coating layer was obtained in the same manner as in Comparative Example 1, except that the surface of the polyethylene sheet on which the adhesive layer was laminated was not subjected to corona discharge treatment.

The pressure-sensitive adhesive sheets of Example 1 and Comparative Examples 1 to 3 were evaluated according to the items shown in Table 1, and the results are shown in Table 1.

[0020]

[Table 1] * To evaluate the adhesion between the polyethylene layer and the adhesive layer, attach an adhesive sheet to a stainless steel plate and
After leaving it for 4 hours, it was peeled off and the adhesive residue was observed. ：: no adhesive residue △: partial adhesive residue ×: many adhesive residues

[0021]

According to the method for producing a pressure-sensitive adhesive sheet of the present invention, the step of laminating a pressure-sensitive adhesive on an olefin-based resin substrate can be omitted, so that the equipment can be simplified and the production efficiency can be improved. In addition, it is possible to obtain a pressure-sensitive adhesive sheet having excellent adhesion to the pressure-sensitive adhesive layer while the base material is an olefin-based resin.

 ──────────────────────────────────────────────────の Continued on the front page F-term (reference) 4F100 AA21H AK01C AK03C AK04 AK06 AL05C BA03 BA07 BA10A BA10C BA31 CA13 DG10B EA061 EH152 EH232 EJ192 GB90 HB00A JB16C JB20C JL02 JL10AJA14 CD05 JL11 JB13A02 AJL14 DA05 DB02 DB04 FA01 GA01

Claims (1)

[Claims] 1. An olefin-based resin and a pressure-sensitive adhesive made of an uncrosslinked thermoplastic resin are co-extruded on one surface of release paper so that the pressure-sensitive adhesive is on the release paper side. A method for producing a pressure-sensitive adhesive sheet, comprising laminating a colored coating film on the adhesive sheet.