JPH0649418A - Production of tacky tape - Google Patents

Abstract

PURPOSE:To obtain a method for producing a tacky tape capable of efficiently and readily forming a tacky agent layer on a substrate composed of a polyolefinic foam sheet having insufficient heat resistance regardless of the thickness without requiring the use of mold release paper even in either of production and use. CONSTITUTION:The objective method for producing a tacky tape is provided with respective steps for coating one surface of a polyolefinic foam sheet having a mold release agent layer formed on the other surface with an acrylic photopolymerizable composition and irradiating the coated photopolymerizable composition with ultraviolet rays in an atmosphere at <=350ppm oxygen concentration.

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 tape suitable for use as, for example, tile joints or cushioning, using a polyolefin resin foam sheet as a substrate.

[0002]

2. Description of the Related Art Conventionally, for tile joints, cushioning applications, etc., an adhesive tape using a base material made of a polyolefin resin foam sheet having excellent flexibility and elasticity has been widely used (for example, JP-B-62). -9636).
The pressure-sensitive adhesive tape, a release paper having a silicone-based release agent layer formed on the surface, a solvent-based or water-based adhesive is applied,
After being dried, it was manufactured by transferring this pressure-sensitive adhesive layer supported by a release paper to a polyolefin resin foam sheet. In use, the release paper was peeled off and attached to the adherend.

The adhesive tape using the polyolefin resin foam sheet as a base material is usually manufactured as a product wound on a core, but the polyolefin resin foam sheet has very high surface strength. Since it is small, if the peeling force between the back surface of the polyolefin resin foam sheet and the pressure-sensitive adhesive layer is large, when the adhesive tape is pulled out during use, the pressure-sensitive adhesive layer is the skin on the back surface of the polyolefin resin foam sheet on the inner peripheral side. It may damage the layers. Therefore, a method has been proposed in which a release paper is attached to the surface of the pressure-sensitive adhesive layer, or the back surface of the polyolefin resin foam sheet is treated with a UV-curing type silicone release agent in order to reduce the peeling force. Japanese Patent Application No. 3-136686).

[0004]

As described above, a release paper is required for forming the pressure-sensitive adhesive layer and transferring it to the polyolefin resin foam sheet. Since this release paper receives heat to dry the applied adhesive in a drying oven, it must have heat resistance. Therefore, it is not possible to use inexpensive polyethylene resin, transfer the pressure-sensitive adhesive layer to the foam sheet using a paper-based release paper with good heat resistance, and then remove the release paper to remove the polyethylene resin. It was necessary to replace it with a resin release sheet for products.

On the other hand, a method of forming a pressure-sensitive adhesive layer by directly coating a solvent-based or water-based pressure-sensitive adhesive on one surface of a polyolefin resin foamed sheet and drying it is also conceivable. However, in general, a polyolefin resin foam sheet has low heat resistance and therefore cannot be heated so much during drying. Therefore, when a solvent-based or water-based pressure-sensitive adhesive is directly applied and dried, the drying process requires a very long time. Therefore,
The productivity of the pressure-sensitive adhesive tape is significantly reduced, and a thick pressure-sensitive adhesive layer cannot be formed.

A method of directly forming the pressure-sensitive adhesive layer on the surface of the polyolefin resin foam sheet using a hot-melt pressure-sensitive adhesive which does not require a long drying step as described above is also conceivable. With a pressure-sensitive adhesive, the temperature at the time of coating is generally as high as about 160 ° C. Therefore, when the pressure-sensitive adhesive is applied to a polyolefin-based resin foam sheet, the foam sheet immediately contracts, and an adhesive tape cannot be obtained.

Therefore, the object of the present invention is that the release paper for transferring the pressure-sensitive adhesive at the time of production is not required, and therefore, the step of reattaching the transfer release paper to the product release sheet can be omitted. A pressure-sensitive adhesive tape comprising a polyolefin-based resin foam sheet as a base material, which can easily and quickly form a pressure-sensitive adhesive layer on one surface of a polyolefin-based resin foam sheet having insufficient heat resistance regardless of the thickness of the pressure-sensitive adhesive layer. It is to provide a manufacturing method.

[0008]

The present invention has been made to achieve the above object, and the method for producing the pressure-sensitive adhesive tape according to claim 1 is a polyolefin resin foam sheet having a release layer on one surface thereof. The surface is coated with an acrylic photopolymerizable composition, and the photopolymerizable composition is irradiated with ultraviolet rays.

In the method for producing a pressure-sensitive adhesive tape according to claim 2, an acrylic photopolymerizable composition is applied to at least one surface of a polyolefin resin foam sheet, and the photopolymerizable composition is irradiated with ultraviolet rays. Forming an adhesive layer,
A release sheet is laminated on the surface of the pressure-sensitive adhesive layer, then the acrylic photopolymerizable composition is applied to the other surface of the foamed sheet, and the pressure-sensitive adhesive layer is formed by irradiating the photopolymerizable composition with ultraviolet rays. It is characterized by

The method for producing an adhesive tape according to claim 3 is characterized in that the release sheet according to claim 2 is a polyolefin resin.

The method for producing a pressure-sensitive adhesive tape according to claim 4 is a cross-linked polyolefin-based film in which a synthetic resin film composed of an elastomer containing an ethylene-α-olefin copolymer as a main component and a low-density polyethylene resin is laminated on one surface. Forming a pressure-sensitive adhesive layer by applying an acrylic photopolymerizable composition to the other surface of the foamed sheet obtained by heat-foaming an unfoamed sheet made of a resin and irradiating the photopolymerizable composition with ultraviolet rays. Characterize.

The details of the method for producing the adhesive tape of the present invention will be described below. Polyolefin-based resin foamed sheet The polyolefin-based resin foamed sheet used in the present invention is a polyolefin-based resin foamed sheet that has heretofore been used for forming joints of tiles or for cushioning purposes. As the polyolefin resin, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ethylene / vinyl acetate copolymer,
One kind or a mixture of two or more kinds such as polypropylene may be mentioned, and an additive such as a pigment may be added to this, if necessary. Further, the polyolefin resin foamed sheet is preferably crosslinked because it has excellent heat resistance and strength and the cells are fine and uniform. Examples of the crosslinking method include irradiation with ionizing radiation and crosslinking with a chemical crosslinking agent. Examples of such a polyolefin resin crosslinked foamed sheet include Sekisui Softlon # 3003 manufactured by Sekisui Chemical Co., Ltd. The thickness of the polyolefin-based resin foam sheet used is not particularly limited because it depends on the application, but a thickness of about 0.5 to 10 mm is usually used.

Release Layer In the production method according to the first and fourth aspects of the present invention, a release layer is formed on one surface of the polyolefin resin foam sheet.
This peeling layer is provided to reduce the peeling force between the back surface of the polyolefin resin foam sheet and the pressure-sensitive adhesive layer when the pressure-sensitive adhesive tape is pulled out from the rolled product. As one of the release layers, there is one formed by applying an appropriate release agent to one surface of the polyolefin resin foam sheet. As a releasing agent that can be used, an appropriate one can be used as long as it does not attack the polyolefin resin foam sheet and does not require heat treatment or the like. An example of such a release agent is solvent-free UV-curable silicone (for example, product name: UV9300 manufactured by General Electric Company). This solventless UV-curable silicone is applied to one surface of a polyolefin resin foam sheet and then cured by irradiation with UV rays to function as a release layer.

Release Sheet In the manufacturing method of claim 2 of the present invention, a release sheet is used instead of the release layer. Examples of the release sheet include a synthetic resin film made of a composition having releasability, and a base material made of paper such as glassine paper having a surface subjected to a release treatment with a silicone resin or the like. In particular, a synthetic resin film made of a composition having releasability includes a mixed resin of an elastomer (A) containing an ethylene-α-olefin copolymer as a main component and a low density polyethylene resin (B). A has a density of 0.80 to 0.90 g / cm ³ and an embrittlement temperature of -70.
Those having a melting point of 80 ° C. or lower, for example, ethylene-propylene random copolymer elastomer are suitable. A is a polyolefin wax in addition to the above components,
It may contain an olefin copolymer graft-modified with an unsaturated carboxylic acid or a derivative thereof. B has an average molecular weight of 10,000 or more and a density of 0.91 to 0.
It is preferably 97 g / cm ³ , and the mixing ratio of A and B is preferably 80:20 to 20:80 by weight. The mixed resin is used by being laminated on the surface of the foamed sheet by heat fusion, extrusion lamination, or the like.

Acrylic Photopolymerizable Composition In the method for producing the pressure-sensitive adhesive tape of the present invention, the surface of the polyolefin resin foam sheet, and the other surface of the polyolefin resin foam sheet having the release layer formed on one surface,
The pressure-sensitive adhesive layer is formed by applying the acrylic photopolymerizable composition and irradiating the photopolymerizable composition with ultraviolet rays under the above-mentioned specific atmosphere. As the acrylic photopolymerizable composition, a photopolymerizable composition that is widely used to obtain a known photopolymerizable acrylic pressure-sensitive adhesive can be used. For example, (meth) acrylic acid alkyl ester is 60 to 10
Examples of the photopolymerizable composition include 0 part by weight and 0 to 40 parts by weight of a vinyl-based monomer copolymerizable with the (meth) acrylic acid alkyl ester, and a photopolymerization initiator.

As the (meth) acrylic acid alkyl ester, those having an alkyl group having 1 to 14 carbon atoms, preferably 4 to 12 carbon atoms are used. Examples of such an alkyl (meth) acrylate ester include n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, or (meth).
Examples thereof include isononyl acrylate. These (meth) acrylic acid alkyl esters may be used alone or in combination of two or more kinds.

Examples of vinyl monomers copolymerizable with the above-mentioned (meth) acrylic acid alkyl ester include acrylic acid, methacrylic acid, acrylamide, acrylonitrile, methacrylonitrile, N-substituted acrylamide, hydroxyethyl acrylate and N. -Vinylpyrrolidone, maleic acid, itaconic acid, n-methylol acrylamide, hydroxyethyl methacrylate, carboxyalkyl acrylate and the like can be mentioned. Of the above vinyl-based monomers, acrylic acid, N-vinylpyrrolidone and carboxyethyl acrylate are preferably used in the present invention. Acrylic acid, N-vinylpyrrolidone and carboxyethyl acrylate not only can enhance the adhesive performance, but also have the action of promoting the polymerization reaction during photopolymerization.

Further, carboxyethyl acrylate, which is a kind of carboxy acrylate, not only enhances the adhesive performance, but also is less likely to evaporate in the light irradiation step in an inert atmosphere, so that the load on the exhaust treatment device can be reduced. Not only that, it is difficult to evaporate in the light irradiation step, so that the loss of raw materials can be reduced, the cost of the pressure-sensitive adhesive tape can be reduced, and the pressure-sensitive adhesive layer having stable performance can be formed.

As the vinyl-based monomer, those capable of forming a polymer having a low glass transition temperature, for example,
Tetrahydrofurfuryl acrylate, benzyl acrylate, cyclohexyl acrylate, isobornyl acrylate, polyethylene glycol acrylate, polypropylene glycol acrylate, fluorine acrylate, silicon acrylate and the like can also be used.
The mixing ratios of the (meth) acrylic acid alkyl ester and the vinyl monomer are set to 60 to 100 parts by weight and 0 to 40 parts by weight, respectively, as long as they are within this range, the balance between tackiness and cohesive force is excellent. This is because the adhesive layer can be formed.

The photopolymerizable composition used in the present invention contains a photopolymerization initiator for initiating photopolymerization. Examples of the photopolymerization initiator which can be used include 4-
(2-Hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone [Ciba Geigy, trade name:
Darocur 2959], α-hydroxy-α, α′-dimethyl-acetophenone [manufactured by Ciba Geigy, trade name:
Darocur 1173], methoxyacetophenone, 2,
Acetophenone type such as 2-dimethoxy-2-phenylacetophenone; Benzoin ether type such as benzoin ethyl ether, benzoin isopropyl ether;
Ketal system such as benzyl dimethyl ketal; other,
Examples thereof include halogenated ketones, acylphosphinoxides, acylphosphonates and the like.

The photopolymerization initiator is added in an amount of 0.001 to 5 parts by weight when the total amount of the above monomer components is 100 parts by weight. This is because if it is less than 0.001 part by weight, it is difficult to start photopolymerization sufficiently, and even if it exceeds 5 parts by weight, the effect of compounding the photopolymerization initiator is saturated. The photopolymerizable composition preferably contains a polyfunctional vinyl compound as a crosslinking agent together with the photopolymerization initiator in order to improve heat resistance and cohesive force at high temperature.

Examples of such crosslinking agents include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth). Acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, other epoxy acrylate,
Examples include polyester acrylate and urethane acrylate.

Generally, the above-mentioned cross-linking agent is preferably added in a proportion of 5 parts by weight or less based on 100 parts by weight of the total of the above-mentioned monomer components, whereby a cross-linking bond is formed between polymer molecules in the course of the photopolymerization reaction. Can be
The heat resistance of the pressure-sensitive adhesive layer and the cohesive force at high temperature can be increased. Further, non-vinyl-based polyfunctional compounds such as isocyanates, epoxies, melamines and aziridines may be added as a crosslinking agent. Further, in the present invention, a tackifying resin may be blended with the photopolymerizable composition.
Examples of tackifying resins that can be used include rosin resins, modified rosin resins, terpene resins, terpene phenol resins, aromatic modified terpene resins, C ₅ and C ₉ petroleum resins, and coumarone indene resins. Further, in the present invention, as long as the object of the present invention is not impaired, the photopolymerizable composition may be added with a commonly used additive such as a thickener, a thixotropic agent, a filler or a filler.

Examples of the thickener include acrylic rubber and epichlorohydrin rubber. Examples of thixotropic agents include colloidal silica and polyvinylpyrrolidone. Examples of the filler include calcium carbonate, titanium oxide, clay and the like. Examples of the filler include an inorganic hollow body such as glass balun, alumina balun, or ceramic balun, an organic spherical body such as nylon beads, acrylic beads or silicon beads, an organic hollow body such as vinylidene chloride, acrylic balun, or polyester, rayon or Monofilaments such as nylon can be used.

In the pressure-sensitive adhesive tape of the present invention, a photopolymerizable composition obtained by mixing the above-mentioned monomer component, photopolymerization initiator and other components is applied to one surface of a base material made of a polyolefin resin foam sheet. Then, it is obtained by irradiating with ultraviolet rays in that state to perform photopolymerization. The thickness of the photopolymerizable composition varies depending on the use, but is usually 1
The thickness is about 0 μm to 500 μm.

Further, the light irradiation performed after coating the pressure-sensitive adhesive layer made of the above-mentioned photopolymerizable composition usually has a wavelength of 400
It is performed using a light source having an emission distribution of nm or less. Examples of light sources that can be used are low-pressure mercury lamps, medium-pressure mercury lamps,
Examples thereof include a high pressure mercury lamp, an ultra high pressure mercury lamp, a chemical lamp, a black light lamp, a microfave excited mercury lamp, and a metal halide lamp. Among these, the ultra-high pressure mercury lamp efficiently emits light in the active wavelength region of the photopolymerization initiator, and has a short wavelength of light such that the viscoelasticity of the resulting polymer is reduced by crosslinking, and the reaction composition. Because it does not emit much long-wavelength light that heats and evaporates
preferable. The above-mentioned advantages of the ultra-high pressure mercury lamp are effectively exhibited in the case of a so-called water-cooled structure in which a circulating water jacket for cooling is attached around the ultra-high pressure mercury lamp.

However, the reaction efficiency is higher when the light absorption spectrum of the photopolymerization initiator in the reaction system and the emission spectrum of the light source match as much as possible. Therefore, in practice, depending on the type of the photopolymerization initiator. It is preferable to select the light source. The irradiation intensity with respect to light irradiation is an important factor that influences the degree of polymerization of the obtained polymer, and can be appropriately controlled according to the desired adhesive performance, but it is a cleavage type light having an acetophenone group. When a polymerization initiator is used, it is preferably about 0.1-100 mw / cm ² .

The photopolymerization reaction is inhibited by oxygen in the air and oxygen dissolved in the reactive composition. As a method of preventing this, there is a method of covering the reactive composition with polyethylene terephthalate (PET) or a fluororesin film and irradiating the photopolymerizable composition with light through the film. Further, the reaction may be carried out in an inert zone having a light-transmissive window in which oxygen is replaced by an inert gas such as nitrogen gas or carbon dioxide gas.

In the production method of the present invention, the surface portion of the photopolymerizable composition is more susceptible to polymerization inhibition by oxygen than the inside of the polymer, and the cohesive force is lower than that inside, so that the cohesiveness of this surface layer portion is reduced. By setting the same level as the inner layer, an adhesive tape having stable adhesive strength and cohesive strength is obtained. When performing light irradiation in the inert zone, it is desirable to constantly feed a constant inert gas into the zone in order to keep the atmospheric oxygen concentration at a low level. Bubbles are generated on the surface of the photopolymerizable composition by the introduced gas, and evaporation of the monomer occurs. In order to suppress the evaporation level of this monomer, it is preferable that the relative velocity of the air flow with respect to the photopolymerizable composition flowed on the substrate in this zone is 1 m / sec or less, further preferably 0. At about 1 m / sec,
Evaporation of the monomers by the air stream is substantially suppressed.

[0030]

According to the method of the invention described in claim 1, since the pressure-sensitive adhesive layer is formed by applying the acrylic photopolymerizable composition to the polyolefin resin foam sheet and irradiating it with ultraviolet rays, a solvent-type or water-based pressure-sensitive adhesive is formed. It does not require a drying step under high temperature unlike the agent. Therefore, even when using a polyolefin resin foam sheet having insufficient heat resistance as a base material, deformation of the base material does not occur, shrinkage or the like occurs, and even in the case of obtaining a pressure-sensitive adhesive sheet with a large thickness of the pressure-sensitive adhesive layer, it takes an extremely short time. An adhesive tape can be manufactured. In addition, release paper for transfer is not required in production.

Further, since the obtained adhesive tape has the release layer formed on the other surface of the polyolefin resin foam sheet, it is wound up after forming the adhesive layer to obtain a rolled product. Therefore, there is no fear that the polyolefin resin foam sheet on the inner peripheral side will be damaged when the adhesive tape is pulled out from the roll. Therefore, it is not necessary to process the release paper even during use.

In the method according to the second aspect of the invention, similarly, unlike the solvent type and water-based pressure-sensitive adhesives, a drying step at high temperature is not required, and therefore, a polyolefin resin foam sheet having insufficient heat resistance is used as a substrate. However, the pressure-sensitive adhesive tape can be produced in an extremely short time even when a pressure-sensitive adhesive sheet having a large thickness of the pressure-sensitive adhesive layer is obtained without causing deformation or shrinkage of the base material. Further, since a release paper for transferring the pressure-sensitive adhesive layer is not required, it is not necessary to remove the release paper used for transfer and replace it with a release sheet for products. Furthermore, although the pressure-sensitive adhesive layer is formed on both sides of the foamed sheet, the release layer cannot be provided on the pressure-sensitive adhesive layer surface, but since the release sheet is laminated on one pressure-sensitive adhesive layer surface,
A pressure-sensitive adhesive tape can be fed out from a roll of this material without damaging the foam sheet, and can be used as a double-sided pressure-sensitive adhesive tape.

According to the method of the third aspect of the present invention, since the release sheet is a polyolefin-based resin, it has good releasability and is highly flexible, so that it is well compatible with the polyolefin-based resin foam sheet, and the processability of manufacturing the release sheet. Good and cheap to get. As in the present invention, in the polymerization by irradiation with ultraviolet rays, heat is not generated or is small, so that a base material having poor heat resistance such as a polyolefin resin release sheet can be used.

According to the method of the invention as set forth in claim 4, a synthetic resin film comprising ethylene-propylene random copolymer elastomer and a low density polyethylene resin having good peelability is laminated on one surface of the unfoamed sheet to heat the unfoamed sheet. Since it is foamed, the foamed sheet has high surface strength. Moreover, the heat of foaming by heating further improves the lamination strength between the synthetic resin film and the foamed sheet. Further, the step of applying and releasing the liquid release agent can be omitted.

The above-mentioned photopolymerizable composition is applied to the surface of the foamed sheet opposite to the synthetic resin film surface and irradiated with ultraviolet rays to form a pressure-sensitive adhesive layer. Therefore, a polyolefin resin foamed sheet having insufficient heat resistance is used as a base material. However, the pressure-sensitive adhesive tape can be produced in an extremely short time even when a pressure-sensitive adhesive sheet having a thick pressure-sensitive adhesive layer is obtained without causing deformation or shrinkage of the base material. Also in this case, release paper for transferring the pressure-sensitive adhesive layer in the production stage is not required, and release paper treatment at the time of use is not required.

[0036]

EXAMPLES The present invention will be clarified below by giving Examples and Comparative Examples of the present invention.

Example 1 Polyolefin resin crosslinked foamed sheet as a substrate (manufactured by Sekisui Chemical Co., Ltd., trade name: Sekisui Softlon, foaming ratio 30)
Double, thickness 3 mm) Solvent-free UV-curable silicone (made by General Electric Co., trade name: UV93)
00) was applied at a rate of 1 g / m ² and was irradiated with ultraviolet rays for 30 seconds by a 160 W ultraviolet irradiation lamp to form a release layer. On the other surface of the above polyolefin resin crosslinked foamed sheet, 100 g of a solventless photopolymerizable composition having the following composition
Application at a ratio of m ² and irradiation intensity of 25 mmW / m ² by an ultraviolet irradiation lamp in an atmosphere with an oxygen concentration of 350 ppm or less.
Was irradiated for 2 minutes to form an adhesive layer, and an adhesive tape was prepared.

2-Ethylhexyl acrylate: 95 parts by weight Acrylic acid: 5 parts by weight Photopolymerization initiator (manufactured by Merck, trade name: Darocur-2959): 0.5 parts by weight AHD (hexanediol diacrylate): 0.1 Parts by weight PS250 (Toa Paint Co., Ltd., acrylic rubber, trade name: Toacron) 30 parts by weight Two adhesives of the above-mentioned adhesive tape are overlapped with each other, and one back and forth pressure is applied by a 2 kg roller, and after standing for 20 minutes, 300 m
Peeling was performed at a speed of / minute, and the peeled state was observed.

Example 2 The polyolefin resin foam sheet used in Example 1 was provided with a release layer in the same manner as in Example 1. A composition comprising 95 parts by weight of 2 ethylhexyl acrylate, 5 parts by weight of acrylic acid, 0.03 part by weight of lauryl mercaptan, and 0.5 part by weight of a photopolymerization initiator (manufactured by Merck & Co., Inc., trade name: Darocur 1173) was put into a flask. Then, the dissolved oxygen was removed by purging with nitrogen gas. The light intensity on the flask surface was 1 mw / cm ² using a black light lamp.
Ultraviolet rays were irradiated under the condition that After irradiation for 5 minutes, the viscosity becomes 3000 cps and the monomer conversion rate is 45%.
Met.

To 100 g of the partially polymerized thickened product, 0.5 g of a photopolymerization initiator Darocur 2959 and a cross-linking agent having an aziridine group (trade name: HDU manufactured by Mutual Yaku Kogyo Co., Ltd.) 0.05
A reactive composition having g added was obtained. This composition was applied to the surface of the foamed sheet opposite to the release layer at 100 g / m ^2, and was irradiated with an ultrahigh pressure mercury lamp at an irradiation intensity of 25 mw / cm ² for 90 seconds under an atmospheric condition of an oxygen concentration of 350 ppm to produce an adhesive. The layer was formed and the adhesive tape was produced.

Example 3 2 A composition containing 90 parts by weight of ethylhexyl acrylate, 10 parts by weight of carboxyethyl acrylate, 5 parts by weight of vinylpyrrolidone, and 1 part by weight of a photopolymerization initiator (manufactured by Merck Ltd., trade name: Darocur 1173) was glass. UV light is emitted from the outside of the container by an ultraviolet radiation fluorescent lamp, and the viscosity is 5
Polymerization up to 00 cps and a conversion of 4.1% and hexanediol diacrylate was added to the reactive thickening composition at a rate of 0.
After adding 028 parts by weight, it is applied to one side of a polyethylene foam sheet (linear low-density polyethylene, expansion ratio 12 times, heating deformation temperature 70 ° C) with a two-roll coater so as to have a thickness of 75 μm, and an inert zone with an oxygen concentration of 300 ppm. With an ultra-high pressure mercury lamp as the radiation source, the lamp intensity on the irradiation surface is 8
The lamp height was set so as to be mw / cm ² , polymerization was carried out by irradiating for 2 minutes, and then the siliconized surface of glassine paper obtained by siliconizing was bonded. The same pressure-sensitive adhesive layer is formed on the opposite surface of the foamed sheet while rewinding and rewinding the same, and one exposed pressure-sensitive adhesive layer is wound up and wound up, and the outer pressure-sensitive adhesive layer surface A double-sided pressure-sensitive adhesive tape having glassine paper stuck to it was obtained.

Example 4 Low density polyethylene resin (density 0.922) powder 100
Parts by weight and 15 parts by weight of azodicarbonamide were mixed in a Henschel mixer, and this mixture was mixed with an extruder to obtain 14 parts by weight.
Knead at 0 ° C and extrude the above polyethylene resin to a thickness of 1
mm crosslinked unfoamed sheet was formed. On one side of the unfoamed sheet, an elastomer composed of ethylene-propylene copolymer (Mitsui Petrochemical Co., Ltd., trade name: Tufmer P-0
A mixture of 30% by weight of 280) and 70% by weight of a low-density polyethylene resin (trade name: Mirason G-16, manufactured by Mitsui Petrochemical Co., Ltd.) was extruded at 280 ° C. to form a 100 μm-thick release layer, and the release layer was not attached. A foamed sheet was obtained. The unfoamed sheet with the release layer was heated and foamed with an electric heater and hot air at 220 ° C. to obtain a foamed sheet. The same photopolymerizable composition as that used in Example 3 was applied to one surface of the unfoamed sheet under the same conditions as in Example 3, and the adhesive tape obtained by polymerization was wound into a roll.

Comparative Example 1 On the other surface of the same polyolefin-based resin foam sheet as used in Example 1, 250 g of a solvent-based adhesive (manufactured by Soken Chemical Co., Ltd., trade name: SK Dyne 1717: concentration 40% by weight).
/ M ² and apply in an oven at 120 ° C,
It was completely dried to prepare an adhesive tape. The pressure-sensitive adhesive tapes thus obtained were superposed on each other, reciprocated once while being pressed by a 2 kg roller, left for 20 minutes, and then peeled off at a speed of 300 m / min.

Comparative Example 2 On the other surface of the same polyolefin-based resin foam sheet used in Example 1, 250 g of a solvent-based adhesive (manufactured by Soken Chemical Co., Ltd., trade name: SK Dyne 1717: concentration 40% by weight).
/ M ² and apply in an oven at 100 ° C,
It was completely dried to prepare an adhesive tape. The pressure-sensitive adhesive tapes thus obtained were superposed on each other, reciprocated once while being pressed by a 2 kg roller, left for 20 minutes, and then peeled off at a speed of 300 m / min.

Comparative Example 3 On the other surface of the same polyolefin resin foamed sheet as used in Example 1, 250 g of a solvent type adhesive (manufactured by Soken Chemical Co., Ltd., trade name: SK Dyne 1717: concentration 40% by weight).
The adhesive tape was prepared by applying the adhesive tape at a ratio of / m ² and heating it in an oven at 80 ° C. to completely dry it. The pressure-sensitive adhesive tapes thus obtained were superposed on each other, reciprocated once while being pressed by a 2 kg roller, left for 20 minutes, and then peeled off at a speed of 300 m / min.

Comparative Example 4 On the other surface of the same polyolefin resin foam sheet as used in Example 1, 250 g of a solvent type adhesive (manufactured by Soken Chemical Co., Ltd., trade name: SK Dyne 1717: concentration 40% by weight).
The adhesive tape was prepared by applying the adhesive tape at a ratio of / m ² and heating it in an oven at 60 ° C. to completely dry it. The pressure-sensitive adhesive tapes thus obtained were superposed on each other, reciprocated once while being pressed by a 2 kg roller, left for 20 minutes, and then peeled off at a speed of 300 m / min.

Comparative Example 5 A monomer composition comprising 90.7 parts by weight of butyl acrylate, 3 parts by weight of methyl methacrylate, 6 parts by weight of acrylic acid and 0.3 part by weight of hydroxyethyl methacrylate was subjected to boiling point polymerization until the molecular weight reached about 120,000. Then, ethyl acetate was added to prepare an adhesive solution having a solid content concentration of 30%.
Crosslinking agent (made by Nippon Polyurethane Industry Co., Ltd.
Product name: Coronate L55) 0.21 parts by weight are mixed,
The same cross-linked polyethylene foam sheet as used in Example 3 was applied to a surface of glassine paper which had been subjected to a peeling treatment with a two-roll coater in a thickness of 250 μm and dried in a drying oven at 80 to 120 ° C. for 5 minutes. Was transferred to one side to obtain an adhesive tape.

The time required for the pressure-sensitive adhesive layers in Examples 1 to 4 and Comparative Examples 1 to 5 to reach a completely dried (cured) state, the state of the polyolefin resin foam sheet in the obtained pressure-sensitive adhesive tape, and the peeling test. The peeled state of the pressure-sensitive adhesive layer was evaluated. The results are shown in Table 1 below.

[0049]

[Table 1]

In Table 1, the evaluation symbols A to D of the state of the polyolefin resin foam sheet have the following contents. A: A state in which the original shape of the polyolefin resin foam sheet is maintained. B: The resin foam sheet was curled. C: The resin foam sheet had some settling. D: A large settling occurred in the resin foam sheet. In the peeling condition evaluation code, ○ means that the adhesive surfaces are peeled off and the adhesive and the polyolefin resin foam sheet are still firmly adhered, and × means the adhesive and the polyolefin on one surface are partially or entirely. It means that it is in a peeled state at the part of the resin foam sheet.

As is clear from the results of the above Examples and Comparative Examples, in the production methods of Comparative Examples 1 to 5, curling and sagging occurred in the polyolefin resin foam sheets, whereas in Example 1 According to the methods (4) to (4), the adhesive tape can be obtained while maintaining the original shape of the polyolefin resin foam sheet. In addition, regarding the peeled state, Example 1
For ~ 4, the anchor strength (adhesive strength) between the adhesive layer and the foam sheet
While the adhesive tape of Comparative Example 4 required 2700 seconds and the adhesive tape of Comparative Example 5 had a viscosity of 3 seconds.
It can be seen that it takes 00 seconds. Therefore, according to the method of the above-mentioned example, it can be seen that an adhesive tape having a polyolefin resin foam sheet as a base material can be produced in a short time without causing deformation of the polyolefin resin foam sheet.

[0052]

As described above, according to the present invention, the above-mentioned acrylic photopolymerizable composition is directly applied to a polyolefin resin foam sheet in the production of an adhesive tape having a polyolefin resin foam sheet as a base material. Then, the pressure-sensitive adhesive layer is formed by polymerizing by ultraviolet irradiation. Therefore,
When forming the pressure-sensitive adhesive layer, since it does not require a drying step at high temperature, without deformation of the foamed sheet,
Moreover, even when the thickness of the pressure-sensitive adhesive layer is increased, the pressure-sensitive adhesive layer can be formed in a short time. Moreover, since the step of transferring the pressure-sensitive adhesive layer can be omitted during production, a release paper for transfer is not required, and therefore, even when a release sheet for products is needed, the step of reattaching to the release sheet can be omitted. it can. Further, the adhesive tape obtained by the method of forming the release layer on the back surface of the polyolefin resin foam sheet,
Since there is no risk of the polyolefin-based resin foam sheet being damaged when the pressure-sensitive adhesive tape formed into a roll is pulled out, the product can be used as a roll as it is. Therefore, since the release paper can be omitted during use, not only can the adhesive tape be attached efficiently, but also unnecessary waste is not generated during use. In order to produce a double-sided pressure-sensitive adhesive tape in which a pressure-sensitive adhesive layer is provided on both sides of a polyolefin-based resin foam sheet, the release layer cannot be used on the surface of the foam sheet, but by a method of laminating a release sheet on one pressure-sensitive adhesive layer surface. , Double-sided adhesive tape as a roll,
This can be easily paid out and used. Further, in the case of using a foamed sheet obtained by heat-foaming a non-foamed sheet in which a synthetic resin film is laminated on one surface of the non-foamed sheet, the surface strength of the foamed sheet is large, and the laminated strength with the foamed sheet is also excellent. It becomes a material. Then, the step of applying and releasing the release agent can be omitted.

Claims (4)

[Claims] 1. An adhesive tape characterized in that an acrylic photopolymerizable composition is applied to the other surface of a polyolefin resin foam sheet having a release layer on one surface, and the photopolymerizable composition is irradiated with ultraviolet rays. Manufacturing method. 2. A pressure-sensitive adhesive layer is formed by coating an acrylic photopolymerizable composition on one surface of a polyolefin resin foam sheet, and irradiating the photopolymerizable composition with ultraviolet rays.
A release sheet is laminated on the surface of the pressure-sensitive adhesive layer, then the acrylic photopolymerizable composition is applied to the other surface of the foamed sheet, and the pressure-sensitive adhesive layer is formed by irradiating the photopolymerizable composition with ultraviolet rays. A method for producing an adhesive tape, comprising: 3. The method for producing an adhesive tape according to claim 2, wherein the release sheet is a polyolefin resin. 4. An unfoamed sheet made of a cross-linked polyolefin resin, which is laminated on one surface with a synthetic resin film made of an elastomer containing an ethylene-α-olefin copolymer as a main component and a low-density polyethylene resin, and heat-foamed. A method for producing an adhesive tape, which comprises applying an acrylic photopolymerizable composition to the other surface of the foamed sheet and irradiating the photopolymerizable composition with ultraviolet rays to form an adhesive layer.