JP2995909B2 - Removable pressure-sensitive adhesive sheet and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a metal plate such as a stainless steel plate, an aluminum plate and a steel plate and a coated metal plate,
Affixed to non-metallic plates such as BS plate, acrylic plate, PVC plate and glass plate, and paper-based adherends such as high quality paper and cardboard,
The present invention relates to a removable pressure-sensitive adhesive sheet that can be easily peeled off even after a long time has passed, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, pressure-sensitive adhesive sheets have been used for commercial, office,
It is used for labels, stickers, patches and the like in a very wide range of fields such as home use. The general configuration of this pressure-sensitive adhesive sheet is a state in which a pressure-sensitive adhesive is sandwiched between a surface substrate and a release sheet.

[0003] Paper, synthetic paper, film, metal foil, etc. are used as the surface base material. A release sheet is coated with a release agent such as a silicone compound or a fluorine compound on glassine paper, clay-coated paper, or polylaminate base paper. Is used. In addition, rubber-based, acrylic-based,
Emulsions such as vinyl ethers and silicones and various adhesives of solvent or non-solvent type are used.

[0004] Such an adhesive sheet is a permanent adhesive type which is permanently used after being attached to a product or the like while being adhered to an adherend, and after a display purpose is achieved in relation to a product or the like. There is a re-peel type which is peeled and discarded. Among the above-mentioned pressure-sensitive adhesive sheets, a removable pressure-sensitive adhesive sheet that is currently in practical use is mainly composed of a carboxyl group and / or a hydroxyl group-containing acrylic copolymer as a pressure-sensitive adhesive,
Add a polyepoxide compound as a crosslinking agent to this,
A two-part crosslinkable pressure-sensitive adhesive in which a carboxyl group and / or a hydroxyl group is crosslinked with an epoxy group has been used.

[0005] When such an adhesive sheet is adhered to a paper-based adherend and a long time has passed, when the adhesive sheet is peeled off, the surface substrate or the adherend surface is destroyed, or the adhesive adheres to the adherend. There is a disadvantage that it remains. In recent years, a pressure-sensitive adhesive sheet of a type in which pressure-sensitive adhesive microspheres are directly applied to a surface substrate has attracted attention as a re-peelable pressure-sensitive adhesive sheet that can be repeatedly adhered to and peeled off from various adherends. However, such a pressure-sensitive adhesive sheet, when the pressure-sensitive adhesive is applied by a transfer method, since sufficient anchoring force and adhesion between the surface substrate and the pressure-sensitive adhesive cannot be obtained, the pressure-sensitive adhesive sheet is directly applied to the surface substrate. It is manufactured by coating. In the production by this direct coating method, if the surface substrate is special paper such as heat-sensitive paper or cast coated paper, there are problems such as unnecessary color development and gloss reduction. Is currently limited to high quality paper.

[0006]

SUMMARY OF THE INVENTION The present invention provides a pressure-sensitive adhesive sheet excellent in removability and a method for producing the pressure-sensitive adhesive sheet by a transfer method.

[0007]

Means for Solving the Problems A first invention of the present application is a release sheet, a coating layer mainly composed of sticky microspheres having an average particle diameter of 30 to 200 μm, measured by a method according to JIS K6301. An adhesive layer having an elongation of at least 600% and a surface substrate are sequentially laminated, and the second invention is based on the surface substrate, JIS K6301. The release sheet was peeled off from the pressure-sensitive adhesive layer obtained by laminating the pressure-sensitive adhesive layer having an elongation percentage of 600% or more and the release sheet, and the exposed pressure-sensitive adhesive layer was separately separated from the pressure-sensitive adhesive layer by an average particle diameter. A method for producing a re-peelable pressure-sensitive adhesive sheet, characterized in that the surface is provided with a coating layer of a release sheet provided with a pressure-sensitive adhesive microsphere having a thickness of 30 to 200 μm as a main component, and the coated layer is finished. Further, in the third invention, the average particle diameter is
JIS K6301 is applied to the surface of the coating layer of the release sheet provided with a coating layer mainly composed of adhesive microspheres having a thickness of 30 to 200 μm.
An adhesive having an elongation of at least 600% as measured by a method conforming to the standard is coated and dried to form an adhesive layer, and a surface substrate is bonded to the surface of the adhesive layer for finishing. This is a method for producing a peelable pressure-sensitive adhesive sheet.

[0008]

As described above, the removable pressure-sensitive adhesive sheet using pressure-sensitive adhesive microspheres as the pressure-sensitive adhesive has excellent removability on metal, non-metal, and paper adherends. Since the agent must be applied directly to the surface substrate and manufactured, for example, when the surface substrate is a thermal paper,
Unnecessary coloring of the surface substrate during heating and drying of the adhesive layer,
In addition, when the surface base material is a high gloss paper such as cast coated paper, the surface base material is coated with a curl correction liquid to correct the curl of the pressure-sensitive adhesive sheet, and the surface base material has a reduced gloss when dried by heat. There are problems such as unevenness. For this reason, the materials that are currently in practical use are currently limited to high-quality papers that do not cause such problems even when direct coating is performed as a surface substrate.

The method of the present invention proposes a method for producing a removable pressure-sensitive adhesive sheet using a pressure-sensitive adhesive containing pressure-sensitive adhesive microspheres as a main component by transfer coating. Even in the case of special paper such as heat-sensitive paper and cast-coated paper, an excellent removable adhesive sheet can be obtained without any abnormality.

The method for producing the pressure-sensitive adhesive sheet according to the present invention is as follows. A first pressure-sensitive adhesive sheet is obtained by applying a pressure-sensitive adhesive having an elongation of at least 600% as measured by a method in accordance with JIS K6301 on a release sheet, drying and bonding a surface substrate with a nip roll. Next, separately, a coating liquid containing an adhesive microsphere having an average particle diameter of 30 to 200 μm as a main component is separately applied to the release sheet, dried, and an adhesive microsphere layer is formed. The desired re-peelable pressure-sensitive adhesive sheet is obtained by peeling off the release sheet from the sheet, bringing the exposed first pressure-sensitive adhesive layer surface into contact with the pressure-sensitive adhesive microsphere layer, and passing between the nip rolls for bonding.

The type of the pressure-sensitive adhesive used for the first pressure-sensitive adhesive sheet is not particularly limited, and may be a rubber type, an acrylic type, a silicone type, etc. , Hot melt type and liquid curing type can be used, but it is important that the elongation measured by a method in accordance with JIS K6301 is 600% or more. By the way, if the elongation is less than 600%, the adhesion with the adhesive microsphere layer becomes insufficient, and the adhesive microspheres remain on the adherend when the attachment and detachment to the adherend are repeated. Cause.

The adhesive microspheres used in the method of the present invention include, for example, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, nonyl Main components are (meth) acrylates such as acrylate, isononyl acrylate, lauryl acrylate, methyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, isononyl methacrylate, and lauryl methacrylate, and these monomers and acrylic acid , Methacrylic acid, itaconic acid, crotonic acid, maleic acid, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth)
Acrylate, N-methylol (meth) acrylamide, (meth) acrylamide, glycidyl (meth) acrylate, glycidyl ether (meth) acrylate,
Vinyl acetate, styrene, (meth) acrylonitrile, trimethylamine (meth) acrylamide, trimethylamine-p-vinylbenzimide, ammonium (meth)
Acrylate, sodium (meth) acrylate, N,
N-dimethyl-N- (β- (meth) acryloxyethyl) ammonium propionate betaine, 1,1-dimethyl-1- (2-hydroxypropyl) amine (meth) acrylimide, 4,4,9-trimethyl -4-azonia-7-oxy-9-decene-1-sulfonate,
It can be produced by copolymerizing a monomer such as 1,1-dimethyl-1- (2,3-dihydroxypropyl) amine (meth) acrylimide. The specific production method is described in, for example, JP-A-50-2736 and 61-148278.
Can be produced by the suspension polymerization method described in No.

In the present invention, it is desirable that the average particle size of the adhesive microspheres is 30 μm or more. By the way, flat
When the uniform particle size is less than 30 μm, the contact area with the adherend increases, and the adhesiveness is increased. At the time of re-peeling, it may cause the surface of the adherend to be broken.

These adhesives and coating liquids are usually adjusted to a viscosity of about 3,000 to 8,000 centipoise by means of adjusting the molecular weight of the acrylate, diluting with water or a solvent, or increasing the viscosity, and coating the release sheet. Although the object, coated device as for example a roll coater in this case, a knife coater, gravure coater or the like is used, a coverage is 5 to 30 g / m ² by dry weight, preferably 10 to 25 g / m ² Appropriate. By the way, if it is less than 5 g / m ² , the effect as a pressure-sensitive adhesive layer is poor, while if it exceeds 30 g / m ² , the effect is saturated, and it should be avoided from the viewpoint of economy and wool (bleeding).

When a coating machine such as a curtain coater is used as a coating device, it is not necessary to manufacture the first pressure-sensitive adhesive sheet in advance, and the pressure-sensitive adhesive sheet desired by the present invention can be easily obtained. Therefore, this is one of preferred embodiments.
Incidentally, the manufacturing method in this case is as follows. That is,

The release sheet has an average particle diameter of 30 to 200 μm
m is coated with a coating liquid mainly composed of adhesive microspheres, and dried to form an adhesive microsphere layer. An adhesive having an elongation of 600% or more measured by a method in accordance with JIS K6301 is applied on the adhesive microsphere layer obtained in the above, for example, using a curtain coater, and dried to form an adhesive layer. After squeezing, a surface substrate is overlapped on the surface of the pressure-sensitive adhesive layer, and passed between nip rolls and joined to obtain a desired removable pressure-sensitive adhesive sheet.

On the other hand, examples of the release sheet include glassine paper, pigment-coated paper coated with a release agent, kraft paper, or polyethylene laminated paper coated with a release agent, or polypropylene film, polyethylene terephthalate. A resin film such as a film coated with a release agent is appropriately used.

As the release agent, a generally known and used silicone resin or a non-silicone resin such as a long-chain alkyl acrylate polymer resin is used. The coating amount of the release agent is adjusted to a dry weight of about 0.05 to 3 g / m ² , and the release agent layer is finished by heat curing, ionizing radiation curing or the like. In addition, as a coating device when applying a release agent to a substrate, for example, a direct gravure coater, a Meyer bar coater, an air knife coater, an offset gravure coater, a multi-stage roll coater, or the like is appropriately used.

As the surface substrate, conventionally used high-quality paper, ordinary art paper, coated paper referred to as coated paper, as well as special paper such as heat-sensitive paper, cast-coated paper, synthetic paper, film, metal foil Etc. can be used as appropriate according to the application.

[0020]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but it is needless to say that the present invention is not limited thereto.

EXAMPLE 1 A silicone release agent (trade name: KS-857, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to a glassine paper of 70 g / m ² in terms of dry weight of 0.9 g / m ^2.
The coating was dried with a bar coater to give a g / m ² to obtain a release sheet (1). An acrylic emulsion adhesive (manufactured by Nippon Carbide Industry Co., Ltd.)
(Trade name: Nicazole L-122, elongation: 1500%) is coated and dried with a reverse roll coater so as to have a dry weight of 15 g / m ^2, and then a heat-sensitive recording paper ( Kanzaki Paper Co., Ltd., product name: KPT-
86H) was adhered with a nip roll to obtain an adhesive sheet (2). Next, a coating liquid containing an adhesive microsphere as a main component (manufactured by Nippon Carbide Industry Co., Ltd., trade name: Nikazol TS-) is formed on the surface of a release sheet (1) prepared separately.
1392, average particle diameter of 50 μm) is applied and dried by a roll coater so as to have a dry weight of 15 g / m ² , while using a nip roll while peeling the release sheet (1) from the pressure-sensitive adhesive sheet (2). Then, the pressure-sensitive adhesive sheet was adhered to the pressure-sensitive adhesive microsphere layer to obtain a pressure-sensitive adhesive sheet.

Example 2 Cast-coated paper (Kanzaki Paper Co., Ltd.) was used as a surface substrate.
The product was manufactured in the same manner as in Example 1, except that a mirror coat (85 g / m ² ) was used.

Example 3 As an acrylic emulsion adhesive, trade name: Cybinol SVC-1, manufactured by Seiden Chemical Co., Ltd., elongation 10
An adhesive sheet was obtained in the same manner as in Example 1 except that 00% was used.

Example 4 Silicone release agent (trade name: KS-845, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to glassine paper of 85 g / m ² in terms of dry weight of 0.9 g / m ^2.
g / m ² was applied with a bar coater and dried to obtain a release sheet. On the surface of the release agent layer of this release sheet, a coating liquid mainly composed of adhesive microspheres (trade name: Nicazole TS-1392, manufactured by Nippon Carbide Industry Co., Ltd., average particle size: 50 μm) is 15 g / m ² by dry weight. And dried by a roll coater to obtain a sticky microsphere layer. Then, an acrylic emulsion adhesive (manufactured by Nippon Carbide Industry Co., Ltd., trade name: Nicazole L-122, elongation: 1500%) was applied on the microsphere layer with a curtain coater so that the dry weight was 15 g / m ^2. After coating and drying, a thermosensitive recording paper (manufactured by Kanzaki Paper Co., Ltd., trade name:
KPT-86H) was overlaid, passed through a nip roll, and bonded to obtain an adhesive sheet.

Comparative Example 1 Thermal recording paper (KPT-86, manufactured by Kanzaki Paper Co., Ltd.)
H) Adhesive microspheres (Nippon Carbide Industry Co., Ltd.)
Product name: Nicazole TS-1392, average particle size 50μ
The coating liquid containing m) as a main component was coated and dried with a roll coater so as to have a dry weight of 15 g / m ^2, and further adhered to a release sheet (1) with a nip roll to obtain an adhesive sheet.

Comparative Example 2 An adhesive sheet was prepared in the same manner as in Comparative Example 1 except that cast coated paper (manufactured by Kanzaki Paper Co., Ltd., trade name: mirror coat, 85 g / m ² ) was used instead of the thermal recording paper. Obtained.

Comparative Example 3 As an acrylic emulsion-type pressure-sensitive adhesive, Sybinol X-491-269E manufactured by Seiden Chemical Co., Ltd. (elongation 400
%) Was used in the same manner as in Example 1 except that the pressure-sensitive adhesive sheet was used. The following evaluations were performed on the seven types of pressure-sensitive adhesive sheets thus obtained, and the results are shown in Table 1.

(Removability) A pressure-sensitive adhesive sheet piece was adhered to the surface of a high-quality paper, and pressed and reciprocated 5 times with a 2 kg roller.
Thirty minutes later, the adhesive sheet piece was peeled off from the high-quality paper, and thereafter, the operations of sticking to the high-quality paper and peeling were performed in the same manner.
Repeating was repeated to evaluate the removability. ：: No decrease in adhesive strength and no residue of sticky microspheres on the surface of high quality paper are observed.

×: Decrease in adhesive strength and sticky microspheres remaining on the surface of high quality paper are observed.

(Suitability of Protecting Surface Base Material) When a heat-sensitive recording paper or a cast-coated paper is used as the surface base material of the pressure-sensitive adhesive sheet, an unnecessary color is formed on the heat-sensitive recording paper, and a gloss is formed on the cast-coated paper. Visual evaluation was made to determine whether there was any decrease or unevenness. ：: Unnecessary coloring, reduction in gloss, unevenness, etc. are not observed.

X: Unnecessary coloring, reduction in gloss, unevenness, etc. are observed.

[0032]

[Table 1]

[0033]

As is evident from Table 1, the pressure-sensitive adhesive sheet obtained by the method of the present invention has a reduced quality of the surface substrate even when the surface substrate is special paper such as thermosensitive recording paper or cast coated paper. This was a pressure-sensitive adhesive sheet having extremely excellent removability without causing any peeling.

Claims (3)

(57) [Claims] 1. A release sheet, a coating layer mainly composed of adhesive microspheres having an average particle diameter of 30 to 200 μm , and an adhesive layer having an elongation of at least 600% as measured by a method in accordance with JIS K6301. A releasable pressure-sensitive adhesive sheet, wherein a surface substrate is sequentially laminated. 2. A release sheet is peeled off from a surface base material, a pressure-sensitive adhesive layer having an elongation of 600% or more measured by a method in accordance with JIS K6301, and a pressure-sensitive adhesive sheet obtained by laminating a release sheet. Pressure-sensitive adhesive layer, separately average particle size 30 to 20
A method for producing a re-peelable pressure-sensitive adhesive sheet, comprising bonding and finishing a surface of a release sheet provided with a coating layer mainly composed of adhesive microspheres having a thickness of 0 μm . 3. Elongation measured by a method in accordance with JIS K6301 on the surface of a release sheet provided with a coating layer mainly composed of adhesive microspheres having an average particle diameter of 30 to 200 μm. A method for producing a removable pressure-sensitive adhesive sheet, comprising applying a pressure-sensitive adhesive having a ratio of at least 600%, drying the pressure-sensitive adhesive layer to form a pressure-sensitive adhesive layer, and bonding a surface substrate to the surface of the pressure-sensitive adhesive layer.