JP2009001606A - Self-adhesive tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-adhesive tape which reduces contamination with harmful substances present in the open-air environment, especially volatile organic compounds (VOC). <P>SOLUTION: The self-adhesive tape has at least a self-adhesive layer and a release layer and may have a base material. The self-adhesive tape is characterized in that the oxygen permeability of either of the base material and the release layer is ≤200 cc/m<SP>2</SP>×24 hr and the emission amount of toluene per unit mass is ≤5 μg/100 cm<SP>2</SP>when the self-adhesive layer is heated at 100°C for 30 min. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive tape in which contamination by harmful substances existing in an outside air environment, particularly volatile organic compounds (VOC), is reduced.

  In recent years, indoor air pollution problems such as sick house syndrome and chemical sensitivity have become social problems. As a causative substance of sick house syndrome, according to guidelines prepared by the Ministry of Health, Labor and Welfare, at present, formaldehyde, nonanal, acetaldehyde, n-tetradecane, toluene, xylene, ethylbenzene, styrene, p-dichlorobenzene, di-n-butyl phthalate Guideline values for a total of 14 substances including di-2-ethylhexyl phthalate, chlorpyrifos, diazinon, and fenocarb are published. For adhesive tapes, it is desired that these causative substances are not used as raw materials and that the amount of these causative substances emitted from the adhesive tape is small.

Conventionally, as a pressure-sensitive adhesive for pressure-sensitive adhesive tapes, a solution polymerization type acrylic pressure-sensitive adhesive, a solution compounding type rubber-based pressure-sensitive adhesive, and the like have been used. Since these solution polymerization type and solution combination type adhesives are synthesized and blended in an organic solvent such as toluene and xylene, a process for producing an adhesive product such as stirring and coating when synthesizing and blending the adhesive. Volatilization of organic solvents in Japan, and the effects on human bodies and environmental impacts caused by the volatilization of organic solvents remaining in adhesives when adhesive products are used in the market are regarded as problems.

  On the other hand, the adhesive tape which reduced the amount of volatile organic compounds (VOC) diffused which does not use the causative substance of the said sick house as a raw material of an adhesive is proposed (for example, patent documents 1-3). However, these adhesive tapes are harmful substances that exist in the open air environment during product inventory, rewinding according to customer's requested size, processing such as round cutting, product transportation, customer processing and inventory, In particular, there is a problem that volatile organic compounds (VOC) are adsorbed on the product, and the amount of VOC emission generated from the product increases with time.

Moreover, the adhesive tape which adsorb | sucked the volatile organic compound by mix | blending an adsorbent in an adhesive and reduced these emitted amounts and odors is proposed (for example, patent document 4, 5). However, these adhesive tapes may be re-dissipated by heating, etc. depending on the type of adsorbent, and harmful substances that exist in the open air environment, especially volatile organics, during product inventory and distribution processes. The compound (VOC) was also adsorbed, and when the adsorption amount reached saturation, the adsorbent could not be taken in any further, resulting in an increase in the VOC emission amount.

JP 2005-139323 A JP 2004-315767 A JP 2006-70242 A JP 2002-180026 JP JP 2006-328264 A

  The subject of this invention is providing the adhesive tape which reduced the contamination by the harmful | toxic substance which exists in an external air environment, especially a volatile organic compound (VOC).

As a result of intensive studies to solve the above-mentioned problems, at least one of the pressure-sensitive adhesive substrate and the release layer in the pressure-sensitive adhesive tape having at least a pressure-sensitive adhesive layer and a release layer and optionally having a base material. The inventors have found that the above problem can be solved by setting the oxygen permeation amount within a specific range, and the present invention has been completed.

That is, the present invention is a pressure-sensitive adhesive tape that has at least a pressure-sensitive adhesive layer and a release layer and may have a base material, and the oxygen transmission amount of at least one of the base material and the release layer is 200 cc / m or 2 ^· 24hrs or less, there is provided an adhesive tape, characterized in that toluene emission per unit mass at the time of the pressure-sensitive adhesive layer was heated at 100 ° C. 30 minutes is 5μg / 100cm ² or less .

  Since the pressure-sensitive adhesive tape of the present invention can reduce contamination by harmful substances present in the outside air environment, particularly volatile organic compounds (VOC), by using a specific base material and release layer, However, the amount of volatile organic compounds such as toluene can be reduced to a low level.

The pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive tape having at least a pressure-sensitive adhesive layer and a release layer, and optionally having a base material, and an oxygen transmission amount of at least one of the base material and the release layer. Is 200 cc / m ² · 24 hrs or less, and the toluene emission amount per unit mass when the pressure-sensitive adhesive layer is heated at 100 ° C. for 30 minutes is 5 μg / 100 cm ² or less.

  The configuration of the pressure-sensitive adhesive tape of the present invention is only required to have at least a pressure-sensitive adhesive layer and a release layer, and the configuration consisting of the pressure-sensitive adhesive layer and the release layer is a substrate-less double-sided adhesive that does not have a substrate. The tape is raised. Moreover, the structure which has a base material can also be used conveniently, the adhesive layer is formed only in the one surface of a base material, and the single side | surface where the peeling layer was provided in the surface opposite to the surface in which the base material of the adhesive layer was provided. The structure of an adhesive tape may be sufficient. Furthermore, the structure of the double-sided adhesive tape with which the adhesive layer was provided in both surfaces of the base material, and the peeling layer was provided in the surface of at least one adhesive layer may be sufficient.

The amount of oxygen permeation is measured by a test method specified in ASTM D 3985. At room temperature (about 23 ° C.), the amount of oxygen (cc) permeated through the substrate and the release layer in units of 24 hours per unit area is measured.
When the oxygen permeation amount of at least one of the substrate and the release layer is 200 cc / m ² · 24 hrs or less, harmful substances existing in the open air environment, especially volatile organic compounds (VOC), can be prevented from entering the adhesive tape laminate. , Contamination of the adhesive tape by them can be reduced. Specifically, the amount of toluene diffused from the adhesive tape is not increased. The oxygen permeation amount is more preferably 150 cc / m ² · 24 hrs or less, and further preferably 100 cc / m ² · 24 hrs or less.

The amount of toluene emitted from the adhesive tape is measured using a head space method of gas chromatography. The sample is sealed in a vial and heated at 100 ° C. for 30 minutes, and then heated gas is injected and measured by gas chromatography (FID detector). When the amount of toluene emission measured by this method is 5 μg / 100 cm ² or less, the adhesive tape is processed by the customer, incorporated in parts and products, and the amount of toluene emission derived from the adhesive tape when distributed to the market is reduced, The impact on the human body and environmental impact can be reduced. The toluene emission amount is more preferably 3 μg / 100 cm ² or less, and further preferably 1 μg / 100 cm ² or less.

The base material and release layer of the pressure-sensitive adhesive tape are not particularly limited except that at least one of the oxygen permeation amounts is 200 cc / m ² · 24 hrs or less.
As the base material of the adhesive tape, polyester film, polypropylene film, polyethylene film, polyimide film or other plastic film alone or a laminate of these plastic films, urethane, polyethylene, rubber-based foam, nonwoven fabric, cloth, metal foil, Known materials such as paper can be used.

  On the other hand, as the release layer, a plastic film such as a polyester film, a polypropylene film, a polyethylene film, and a polyimide film, or a laminate of these plastic films, paper such as high-quality paper, glassine paper, and Kurpac paper, and polyethylene on these papers, etc. A known material such as one obtained by laminating or impregnating the above resin layer with a silicone-based or non-silicone-based release agent may be used.

However, in order to set the oxygen permeation amount of the adhesive tape to 200 cc / m ² · 24 hrs or less, at least one of these base materials and the release layer needs to have gas barrier properties. It is preferable that has a gas barrier property. Examples of gas barrier materials include plastic films such as polyester, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, and nylon, metal foils such as aluminum foil, stainless steel foil, and copper foil, and these gas barriers for materials with low gas barrier properties. For example, laminated products of aluminum materials, aluminum vapor-deposited products, and the like.

  Especially, it is preferable that at least one of the base material and the release layer has a resin layer made of polyester, polyvinyl alcohol or ethylene-vinyl alcohol copolymer, and it is a single layer film made only of the resin layer. Or the multilayer film which has the said resin layer as at least one layer of the laminated | stacked several layer may be sufficient.

  In addition, for these base materials and release layers, formaldehyde, nonanal, acetaldehyde, n-tetradecane, toluene, xylene, ethylbenzene, styrene, which are currently listed as causative substances for sick house syndrome in the guidelines created by the Ministry of Health, Labor and Welfare It is preferable that a total of 14 substances such as p-dichlorobenzene, di-n-butyl phthalate, di-2-ethylhexyl phthalate, chlorpyrifos, diazinon, and fenocarb are not used as raw materials.

  The thickness of the base material and release layer to be used is not particularly limited as long as it has the oxygen permeation amount, but from the viewpoint of cost, ease of availability, ease of production, workability of the adhesive tape, etc. The substrate is preferably 5 to 250 μm, more preferably 10 to 100 μm, and the release layer is preferably 15 to 500 μm, more preferably 25 to 200 μm.

The pressure-sensitive adhesive layer used in the pressure-sensitive adhesive tape of the present invention is not particularly limited as long as the amount of toluene emission per unit mass when heated at 100 ° C. for 30 minutes is 5 μg / 100 cm ² or less. Various pressure-sensitive adhesives such as silicone can be used. Types of adhesives and coating methods include solvent types prepared by dissolving in organic solvents, emulsion types that are dispersed in water, hot melt types that are applied by heating and melting, and adhesives that are irradiated with ultraviolet rays or electron beams. UV irradiation type, electron beam irradiation type, etc., for curing and polymerizing. However, for adhesives, formaldehyde, nonanal, acetaldehyde, n-tetradecane, toluene, xylene, ethylbenzene, styrene, p-dichlorobenzene, which are currently listed as causative substances for sick house syndrome in the guidelines prepared by the Ministry of Health, Labor and Welfare , Di-n-butyl phthalate, di-2-ethylhexyl phthalate, chlorpyrifos, diazinon, and fenobucarb are preferably not used as raw materials.

  The preferable thickness of the pressure-sensitive adhesive layer is 30 to 300 μm, preferably 50 to 200 μm, after drying.

To reduce the amount of toluene emitted per unit mass when heated at 100 ° C. for 30 minutes to 5 μg / 100 cm ² or less, do not use toluene as a raw material for the pressure-sensitive adhesive. In the case of the solvent dilution type, use an organic solvent other than toluene as the dilution solvent for the production adhesive, thoroughly dry the solvent after applying the adhesive, and adjust the toluene concentration in the production process atmosphere of the adhesive tape. And a method of adsorbing with an adsorbent. Examples of the toluene-diluting solvent for the solvent dilution type include ethyl acetate, normal hexane, methyl ethyl ketone, methyl isobutyl ketone, and acetone. In addition, in order to sufficiently dry the solvent after the adhesive is applied, the drying temperature is increased, the residence time in the drying furnace is increased, the drying air volume is increased, the interior of the drying furnace is set to a negative pressure, Examples of the method include heating with infrared rays and infrared lamps. To reduce the toluene concentration in the production process atmosphere of adhesive tape, do not bring toluene into the process, ventilate with fresh air with low toluene concentration, circulate air and adsorb with adsorption filter, catalytic combustion device for air And a purification method using an ozonolysis apparatus. For adsorption by adsorbent, seal the adhesive tape with an adsorbent such as activated carbon to adsorb toluene to the adsorbent, and apply the adsorbent to the adhesive layer, base material layer, and release layer of the adhesive tape. , Kneading, or carrying on time.

  Further, volatile organic compounds other than the guide substances of the guidelines prepared by the Ministry of Health, Labor and Welfare are concerned about adverse effects on the human body and the environment, and an adhesive tape using a solventless type adhesive is more preferable. Examples of the solventless type pressure-sensitive adhesive include emulsion type, hot melt type, and ultraviolet curable type. Among them, an adhesive that uses an existing production facility and uses a highly safe water-dispersed acrylic resin is suitable.

  The pressure-sensitive adhesive using a water-dispersed acrylic resin is a water-dispersed pressure-sensitive adhesive containing a water-dispersed acrylic resin mainly composed of a (meth) acrylic acid alkyl ester monomer. A known compound can be used as the (meth) acrylic acid alkyl ester monomer. Examples of such compounds include ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) ) Acrylate, isoamyl (meth) acrylate, isodecyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-chloro-2-hydroxy Propyl (meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, nonylphenoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) Acrylate, glycidyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, nonyl phenoxyethyl tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl (meth) acrylate. In this specification, (meth) acrylic acid means acrylic acid or methacrylic acid, and the same applies to derivatives of acrylic acid or methacrylic acid.

  Among the (meth) acrylic acid alkyl ester monomers, it is preferable to use a compound represented by the following formula (1).

（式中、R₁は分岐鎖を有していても良い炭素数４〜１８のアルキル基を表し、Ｘは水素原子又はメチル基を表す。）

(In the formula, R ₁ represents an alkyl group having 4 to 18 carbon atoms which may have a branched chain, and X represents a hydrogen atom or a methyl group.)

  The copolymerization ratio of the monomer represented by the formula (1) in the acrylic copolymer resin is preferably 60 to 98% by mass, more preferably 80 to 97% by mass with respect to all monomers. If it is the said range, both adhesive force and cohesion force are favorable.

In order to use a water-dispersed acrylic resin as a pressure-sensitive adhesive resin, among the monomers represented by the formula (1), R ¹ in the formula (1) may have a branched chain having 4 to 4 carbon atoms. It is preferable that it is an 18 alkyl group, and it is preferable that it is a compound whose glass transition point at the time of a homopolymerization is -10 degrees C or less. Such monomers include butyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, dodecyl methacrylate, octadecyl methacrylate, and the like. The use ratio of such a monomer is preferably 60 to 98% by mass, more preferably 80 to 97% by mass with respect to the total monomers. If it is the said range, both adhesive force and cohesion force are favorable.

  Further, the acrylic copolymer resin may be copolymerized with a highly polar vinyl monomer. Examples of the highly polar vinyl monomer include a monomer having a hydroxyl group, a monomer having a carboxyl group, a monomer having an amino group, and a monomer having a glycidyl group. As the monomer having a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol acrylate, polypropylene glycol acrylate, etc., as monomers having a carboxyl group, (Meth) acrylic acid, itaconic acid, maleic acid, maleic anhydride, (meth) acrylic acid dimer, crotonic acid, etc., have N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine as monomers having amino groups. Dimethylaminoethyl acrylate, acrylamide, N, N-dimethylacrylamide and the like. Other examples include sulfonic acid group-containing monomers such as vinyl acetate, ethylene oxide-modified succinic acid acrylate, and 2-acrylamido-2-methylpropanesulfonic acid.

  The copolymerization ratio of the highly polar vinyl monomer used for the production of the acrylic copolymer resin is preferably 0.5 to 15% by mass. More preferably, it is 1.5-10 mass%, More preferably, it is 2-8 mass%. If it is the said range, the mechanical stability of water dispersion type acrylic resin and the stability (polymerization stability) of the emulsion liquid at the time of emulsion polymerization will be favorable, and the adhesive force and cohesion force of an adhesive will be favorable.

A water-dispersed pressure-sensitive adhesive containing a water-dispersed acrylic resin mainly composed of a (meth) acrylic acid alkyl ester monomer is preferably emulsion-polymerized and then crosslinked with a crosslinking agent. As the crosslinking agent, known isocyanates, epoxy compounds, aziridine compounds, polyvalent metal salts, metal chelates, organic peroxides, and the like can be used. However, a type in which a crosslinking agent is added after the polymerization is completed to advance the crosslinking reaction is preferable. . For example, an epoxy compound, an isocyanate compound, etc. are mentioned.

  As an index of the degree of crosslinking of the acrylic resin, the value of the gel fraction for measuring the insoluble content after the resin layer is immersed in toluene for 24 hours is used. The gel fraction of the pressure-sensitive adhesive layer is less than 5% by mass after emulsion polymerization and before crosslinking, and preferably 20 to 50% by mass after crosslinking with a crosslinking agent. Furthermore, after emulsion polymerization, it is less than 3% by mass before crosslinking, and more preferably 25 to 40% by mass after crosslinking with a crosslinking agent. If the gel fraction of the pressure-sensitive adhesive layer is within the above range, it becomes a water-dispersed acrylic pressure-sensitive adhesive resin having a small branching or cross-linking structure, a flexible molecular chain, and an appropriate cohesive force. In addition to good initial adhesion to adherends that have irregularities on the surface, such as the urethane foam used, impregnation into non-woven fabric base material, good adhesion and peeling resistance and retention when stress is applied Is good.

  In emulsion polymerization, an azo-based, peroxide-based, redox-based or other heat-induced polymerization initiator is used for publicly known purposes. In emulsion polymerization of acrylic resins, in order to keep the gel fraction after emulsion polymerization low, it is necessary to control the branching reaction, and it is easy to decompose even at low temperatures. It is required to have a small hydrogen abstraction effect. Among the above initiators, an azo polymerization initiator is preferably used.

  When an azo initiator is used, there is no generation of aggregates when a nonionic or anionic water-soluble azo initiator is used rather than a cationic water-soluble azo initiator among azo initiators. Branching reaction can be suppressed. When a cationic water-soluble azo initiator is used, for example, when an anionic surfactant is used, an ion pair is likely to be generated, and the stability of the emulsion is reduced, resulting in the formation of aggregates. It becomes difficult. On the other hand, the nonionic or anionic water-soluble azo initiator does not generate an ion pair with the anionic surfactant, so that the stability of the emulsion is maintained and the production without the generation of aggregates becomes possible. .

  The 10-hour half-life temperature of the nonionic or anionic water-soluble azo initiator is preferably 80 ° C. or less. More preferably, the 10-hour half-life temperature is 70 ° C. or lower.

  The polymerization temperature is preferably set to a temperature lower than the 10-hour half-life temperature of the initiator (however, limited to the range in which the initiation reaction is performed). By carrying out the polymerization at a temperature lower than the 10-hour half-life temperature of the initiator, the radical concentration can be kept low and the branching reaction can be restrained, so that a highly flexible adhesive resin can be produced. High initial adhesion to an adherend having irregularities on the surface such as foam, and excellent peeling resistance can be exhibited. Preferably, the temperature is set to a temperature lower by 5 to 30 ° C, more preferably 10 to 30 ° C lower than the 10-hour half-life temperature. However, it is not preferable at a temperature lower than 30 ° C. because polymerization hardly proceeds.

  In the case of an azo initiator having a 10-hour half-life temperature of 69 ° C, the polymerization temperature is preferably 64 ° C to 39 ° C. More preferably, it is 59 degreeC-39 degreeC.

  The initiator addition amount is preferably in the range of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the total monomer amount. When the amount is 0.01 parts by mass or less, the polymerization reaction does not easily proceed and the production becomes difficult. If it is 5.0 parts by mass or more, the branching reaction is likely to proceed, the gel fraction after emulsion polymerization is large, and the flexibility of the pressure-sensitive adhesive is lowered. The range of 0.1-3.0 mass parts is more preferable.

  As an emulsifier used in emulsion polymerization, an anionic surfactant is widely used. In general, nonionic surfactants have a low critical micelle concentration and tend to form micelles with a small amount of emulsifier, but anionic surfactants are more suitable for emulsion polymerization because of higher polymerization stability. The reason why the anionic surfactant is more stably polymerized is that the surface charge of the formed particles is increased.

As the anionic surfactant, known and publicly used ones are used. Examples include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzene sulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, ammonium polyoxyethylene alkyl phenyl ether sulfate, sodium polyoxyethylene alkyl sulfosuccinate, etc. It is done.
One or more of these are used.

  In an anionic surfactant, particles tend to exist independently due to electrical repulsion, so that even when the radical concentration is low, the polymerization stability is kept high and production without occurrence of aggregates becomes possible. The anionic surfactant is preferably used in the range of 0.5 part to 2.0 parts by weight with respect to 100 parts by weight of the acrylic monomer. If it is the said range, emulsification stability is favorable and the adhesive force and water resistance of an adhesive sheet are favorable.

  Among the anionic surfactants, an anionic surfactant having a copolymerizable double bond is preferable. Since an anionic surfactant having a copolymerizable double bond is copolymerized with a reactive monomer, it has little influence on adhesive performance such as adhesive strength and cohesive strength and water resistance, and has an uneven surface. High initial adhesive strength and excellent cohesive strength can be expressed.

  Next, examples of the polymerization method for the acrylic pressure-sensitive adhesive composition include a batch polymerization method, a pre-emulsion method, a monomer dropping method, and the like. Among these, the pre-emulsion method in which water, a monomer, and an emulsifier mixed in advance are added dropwise, so that the polymerization stability is high, so that no agglomerates are generated when the pressure-sensitive adhesive composition is applied. This is preferable because no defect occurs.

  Moreover, you may use a chain transfer agent for superposition | polymerization. By using a chain transfer agent, the molecular weight of the acrylic polymer can be adjusted. Examples of the chain transfer agent include known chain transfer agents such as lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimethylcapto-1-propanol. Can be used.

  Moreover, it is preferable to use a crosslinking agent for the purpose of improving the cohesive strength of the pressure-sensitive adhesive. As the crosslinking agent, known isocyanates, epoxy compounds, aziridine compounds, polyvalent metal salts, metal chelates, organic peroxides, and the like can be used. However, a type in which a crosslinking agent is added after the polymerization is completed to advance the crosslinking reaction is preferable. . For example, an epoxy compound, an isocyanate compound, etc. are mentioned.

  Moreover, tackifying resin can be added for the purpose of improving the initial adhesiveness and peeling resistance to the adherend having an uneven surface such as urethane foam.

  As tackifying resins, known aliphatic petroleum resins, aromatic petroleum resins, alicyclic petroleum resins and other petroleum resins, rosin resins, rosin ester resins, disproportionated rosin resins, polymerized rosin resins, polymerization One or more types of tackifying resins selected from rosin resins such as rosin ester resins and rosin phenol resins, terpene resins, terpene phenol resins, coumarone indene resins and the like can be used. Among them, in order to be compatible with the acrylic copolymer resin and improve the adhesion and peel resistance, the molecular structure of polymerized rosin ester resins, rosin phenol resins, terpene phenol resins, etc. is relatively bulky. Higher resins are preferred. Further, in order to improve the peel resistance, a tackifying resin having a relatively high molecular weight with a softening point of 140 ° C. or higher and lower than 200 ° C. and a high glass transition temperature, in particular, a polymerized rosin ester resin, rosin Phenol resins and terpene phenol resins are preferred.

  As for the addition amount of tackifying resin, 10-40 mass parts is preferable. More preferably, it is 15-35 parts, More preferably, it is 20-35 parts. By setting the addition amount of the tackifying resin in the range of 10 to 40 parts by mass, the initial adhesive force and the peel resistance to an adherend having an uneven surface such as urethane foam are good.

  As a method of adding such a tackifying resin, there is a method of blending a separately emulsified tackifying resin after emulsion polymerization of an alkyl acrylate monomer.

  In addition, the water-dispersed pressure-sensitive adhesive composition includes a plasticizer, a softener, an antioxidant, glass and plastic fibers, balloons, beads, and metal as long as the desired effect of the present invention is not inhibited as necessary. Fillers such as powders, colorants such as pigments and dyes, pH adjusters, film forming aids, leveling agents, thickeners, water repellents, antifoaming agents and the like can be optionally added. .

  In the double-sided pressure-sensitive adhesive tape of the present invention, by containing an adsorbent that adsorbs a volatile organic compound in any of the base material, the pressure-sensitive adhesive layer and the release layer, the volatile property remaining in the pressure-sensitive adhesive tape after production of the pressure-sensitive adhesive tape The organic compound component can be adsorbed and the amount of VOC emission generated from the adhesive tape can be further reduced.

  As the kind of the adsorbent, known ones such as a physical adsorbent such as activated carbon, silica gel, alumina, and zeolite, and a chemical adsorbent can be used, and among them, activated carbon and zeolite can be preferably used.

  Examples of the method for adding the adsorbent to the base material and the release layer include kneading, blending, dispersion, coating and supporting on the surface of the base material and the release layer support. For example, in the case of polyethylene resin laminate release paper, it is supported between the polyethylene resin layer and the paper, and in the case of a nonwoven fabric substrate, it is supported in the nonwoven fabric. Or you may carry | support between a base material and an adhesive layer. Moreover, when adding in an adhesive layer, in order to make adsorption performance and adhesive performance compatible, it is preferable that content of the adsorption agent in an adhesive layer is 0.1-50 mass%.

  The pressure-sensitive adhesive tape of the present invention can be prepared by a generally used method. For example, it is manufactured by forming a pressure-sensitive adhesive layer directly on the base material or release paper, or by forming a pressure-sensitive adhesive layer on the release paper and then sticking it to the pressure-sensitive adhesive layer or base material prepared on the release paper in the same manner it can. In order to form a pressure-sensitive adhesive layer on a substrate or a release layer, a method in which a pressure-sensitive adhesive solution is directly applied onto a support with a roll coater or a die coater, or a pressure-sensitive adhesive layer once formed on a separator and then a support The transfer method is used.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

(Example 1)
(1) Preparation of Emulsion A A container was charged with 10 parts of the anionic surfactant Latemul S-180 (manufactured by Kao Corporation; active ingredient 50%) and 100 parts of deionized water and dissolved uniformly. Thereto, 325 parts of n-butyl acrylate, 160 parts of 2-ethylhexyl acrylate, 20 parts of acrylic acid and 0.5 part of lauryl mercaptan were added and emulsified to obtain an emulsion A (615.5 parts).

(2) Production of water-dispersed acrylic polymer In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 0.1 part of S-180 and 350 parts of deionized water were placed. The temperature was raised to 55 ° C. while blowing nitrogen. Under stirring, anionic water-soluble polymerization initiator V-501 [manufactured by Wako Pure Chemical Industries, Ltd .; active ingredient 100%] 5 parts of aqueous solution (active ingredient 5%) was added, and then emulsion A was 6.2. Polymerization was performed for 1 hour while maintaining 55 ° C. Subsequently, a part (300 parts) of the remaining emulsion A and 20 parts of V-501 aqueous solution (active ingredient 5%) were added over 4 hours while maintaining the reaction vessel at 55 ° C. using a separate dropping funnel. It was dropped and polymerized. During this period, 5 parts of Aqualon KH-10 [Daiichi Kogyo Seiyaku Co., Ltd., active ingredient 100%] is added to emulsion A (308.8 parts) that was not added dropwise, and stirred until uniform. B (313.8 parts) was prepared.

  Immediately after the completion of dropping of emulsion A, emulsion B (313.8 parts) and V-501 aqueous solution 20 parts (active ingredient 5%) were used for 4 hours while maintaining the reaction vessel at 55 ° C. using separate dropping funnels. Over the course of dropwise addition to produce a water-dispersed acrylic polymer.

  After completion of the dropwise addition, the mixture was stirred at the same temperature for 2 hours, and then the contents were cooled and adjusted with ammonia water so that the pH was 7.5. This was filtered through a 200-mesh wire mesh to obtain the water-dispersed acrylic polymer of the present invention. The water-dispersed acrylic polymer obtained here had a solid content concentration of 49.5%, a viscosity of 460 mPa · s, and an average particle size of 270 nm.

(3) Production of water-dispersed acrylic pressure-sensitive adhesive composition 1.2 parts of Surfinol 420 (produced by Air Products Japan; active ingredient 100%) as a leveling agent in the water-dispersed acrylic polymer described above, After adding 1 part of Epocross WS-500 (manufactured by Nippon Shokubai Co., Ltd .; active ingredient 50%), the mixture is filtered through a 100 mesh wire netting, and epoxy compound tetrad C [manufactured by Mitsubishi Gas Chemical Co., Ltd.] is added as a cross-linking agent. 05 parts by mass, 40 parts by mass of water-dispersed isobutyl acrylate prepared separately were added, and rosin-based resin superester E-788 (manufactured by Arakawa Chemical Industries, Ltd .; softening point 160 ° C.) was solidified as a tackifying resin. 15 parts by mass was added in minutes to obtain the water-dispersed acrylic pressure-sensitive adhesive composition of the present invention.

(4) Preparation of double-sided pressure-sensitive adhesive tape On a polyester film having a thickness of 38 μm from which the water-dispersed acrylic pressure-sensitive adhesive composition was peeled off, it was applied so that the thickness after drying was 65 μm. The pressure-sensitive adhesive layer obtained by drying for 3 minutes was transferred to both surfaces of a nonwoven fabric containing 14 g / m ^{2 of} mass (basis weight) and 50/50% by weight of rayon / pulp to obtain a roll-shaped double-sided pressure-sensitive adhesive tape. It was. The obtained double-sided adhesive tape was used for the test after aging in an oven at 40 ° C. for 2 days. The gel fraction (after crosslinking) of the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive tape was 35%.

(Example 2)
The double-sided pressure-sensitive adhesive tape was subjected to the same operation as in Example 1 except that the release layer on which the adhesive was applied was a high-quality paper with a basis weight of 80 g / m ² laminated on both sides with polyethylene and the base material was changed to a polyester film with a thickness of 16 μm. Was made.

(Example 3)
The release layer on which the adhesive is applied is made of high-quality paper with a basis weight of 80 g / m ² laminated on both sides with polyethylene, and the base material is a 50 μm-thick polyethylene / EVOH / polyethylene multilayer film (manufactured by Dainippon Ink & Chemicals, Inc.) A double-sided pressure-sensitive adhesive tape was prepared in the same manner as in Example 1 except that the difference was changed to Differen G-4100).

(Example 2)
Example 1 except that the pressure-sensitive adhesive was coated on a polyester film having a thickness of 38 μm, dried at 100 ° C. for 3 minutes, sprinkled activated carbon on the surface of the pressure-sensitive adhesive layer, and then transferred to both sides of the nonwoven fabric. A double-sided adhesive tape was prepared by the same operation.

(Comparative Example 1)
A double-sided pressure-sensitive adhesive tape was prepared in the same manner as in Example 1, except that the release layer to which the pressure-sensitive adhesive was applied was changed to a high-quality paper having a basis weight of 80 g / m ² laminated on both sides with polyethylene.

(Comparative Example 2)
A double-sided pressure-sensitive adhesive tape was prepared in the same manner as in Example 1 except that the release layer on which the pressure-sensitive adhesive was applied was changed to glassine paper having a basis weight of 60 g / m ² impregnated on both sides with polyvinyl alcohol.

(Comparative Example 1)
The adhesive is coated on high-quality paper with a weight of 80 g / m ² laminated on both sides with polyethylene, dried at 100 ° C. for 3 minutes, sprinkled with activated carbon on the surface of the adhesive layer, and then transferred onto both sides of the nonwoven fabric. A double-sided pressure-sensitive adhesive tape was prepared by the same operation as in Example 1 except that.

  Table 1 shows the evaluation results of the amount of toluene generated from each double-sided pressure-sensitive adhesive tape. The measurement of oxygen permeability and the amount of toluene generation were performed by the following methods.

(Measurement of oxygen transmission rate)
The amount of oxygen permeation was measured by a test method specified in ASTM D 3985. At room temperature (about 23 ° C.), the amount of oxygen (cc) permeating through the substrate and the release layer in units of 24 hours per unit area was measured using a measuring instrument OX-TRAN TWIN manufactured by COMON.

[Measurement method of toluene generation and toluene adsorption]
As a blank value, the amount of toluene was measured for a roll-shaped double-sided adhesive tape before treatment.
Next, the roll-shaped double-sided pressure-sensitive adhesive tape was left at 40 ° C. for 3 days in an atmosphere having a toluene concentration of 25 ppm. In a clean atmosphere, a portion of the tape from which the surface layer of the treated tape was removed was sampled, and the amount of toluene generated after the treatment was measured.
The amount of toluene emission generated from the adhesive tape was measured using the headspace method of gas chromatography. The sample was sealed in a vial and heated at 100 ° C. for 30 minutes, and then heated gas was injected and measured by gas chromatography (FID detector).
The toluene adsorption amount was calculated by the following formula (1).
Toluene adsorption amount = (Toluene generation amount after treatment-Blank toluene generation amount) (1)

  As is apparent from Table 1, the pressure-sensitive adhesive tapes of the present invention shown in Examples 1 to 4 had very little adsorption of toluene even in a high concentration toluene atmosphere. Moreover, the pressure-sensitive adhesive tape of Example 4 carrying the adsorbent was suitable for the toluene diffusion in the pressure-sensitive adhesive layer by adsorbing toluene in the pressure-sensitive adhesive layer. On the other hand, even if the adhesive tape of Comparative Examples 1-3 formed the adhesive layer with low toluene content, toluene was adsorbed in large quantities in the toluene high concentration atmosphere.

Claims (7)

An adhesive tape having at least a pressure-sensitive adhesive layer and a release layer, and optionally having a substrate, wherein the oxygen permeation amount of at least one of the substrate and the release layer is 200 cc / m ² · 24 hrs or less. A pressure-sensitive adhesive tape, wherein the pressure-sensitive adhesive layer has a toluene emission amount of 5 μg / 100 cm ² or less when heated at 100 ° C. for 30 minutes. The pressure-sensitive adhesive tape according to claim 1, wherein at least one of the base material and the release layer has a resin layer made of polyester, polyvinyl alcohol, or ethylene-vinyl alcohol copolymer. The pressure-sensitive adhesive tape according to claim 1 or 2, wherein the pressure-sensitive adhesive layer is a water-dispersed pressure-sensitive adhesive. The pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein at least one of the substrate, the pressure-sensitive adhesive layer, and the release layer contains an adsorbent that adsorbs a volatile organic compound. The volatile organic compound is formaldehyde, nonanal, acetaldehyde, n-tetradecane, toluene, xylene, ethylbenzene, styrene, p-dichlorobenzene, di-n-butyl phthalate, di-2-ethylhexyl phthalate, chlorpyrifos, diazinon, The pressure-sensitive adhesive tape according to claim 4, wherein the pressure-sensitive adhesive tape is at least one selected from fenocarbs. The pressure-sensitive adhesive tape according to claim 4 or 5, wherein the adsorbent is at least one selected from activated carbon or zeolite. The pressure-sensitive adhesive tape according to any one of claims 4 to 6, wherein the adsorbent is contained in the pressure-sensitive adhesive layer, and the content of the adsorbent in the pressure-sensitive adhesive layer is 0.1 to 50% by mass.