JP5602396B2 - Adhesive sheets - Google Patents

Description

  The present invention relates to pressure-sensitive adhesive sheets, and more specifically, pressure-sensitive adhesive sheets (pressure-sensitive adhesive tape, pressure-sensitive adhesive sheet, high-adhesiveness and excellent terminal peeling prevention property and extremely low formaldehyde and toluene emissions). Adhesive film).

  The water-dispersed acrylic pressure-sensitive adhesive using a water-dispersed acrylic polymer is desirable for environmental hygiene because it does not use an organic solvent as a solvent unlike the solvent-type acrylic pressure-sensitive adhesive. It has the advantage that it is excellent also from a viewpoint. In general, in an adhesive layer using an acrylic adhesive, the acrylic polymer has low adhesiveness and terminal peeling prevention properties (characteristics that the end portion is difficult to peel off after being attached to an adherend) and is expressed. For this reason, the use of an emulsion containing a tackifying resin enhances adhesion and terminal peeling prevention. However, an emulsion containing a tackifier resin may use an organic solvent in the production process for the purpose of reducing the melt viscosity or melt viscosity of the tackifier resin (see Patent Document 1). In order to produce an emulsion containing a tackifying resin without using an organic solvent, the emulsion must be emulsified under a high temperature and a high pressure, and a resin having a high softening temperature (for example, having a softening point of 130 ° C. or higher). In the case of resins, etc., the method is very difficult, and the type and amount of emulsifier used are often greatly limited. On the other hand, a resin having a low softening temperature (for example, a resin having a softening point of less than 130 ° C.) may be melted and emulsified by heating without using an organic solvent. It is thought that high adhesiveness, excellent terminal peeling prevention property, heat resistance and the like are difficult to obtain with a low temperature tackifying resin alone, and the use of the produced pressure sensitive adhesive sheets is limited.

  As described above, in order to improve workability when lowering the melt viscosity and melt viscosity of a tackifying resin having a high softening point, and to expand the degree of freedom of types and amounts of emulsifiers used, satisfy the adhesive properties. For this reason, the tackifier resin may be dissolved or melted using an organic solvent. Usually, although the solvent is distilled off under reduced pressure, there is a problem in that the organic solvent remains in a trace amount in the final product. It was. As such an organic solvent, an aromatic hydrocarbon organic solvent such as toluene is generally used from the viewpoint of workability and cost, but the aromatic hydrocarbon organic solvent is highly toxic, The use of pressure-sensitive adhesives and pressure-sensitive adhesive sheets with remaining aromatic hydrocarbon-based organic solvents is a concern for the impact on the environment. Especially in applications in sealed spaces such as automobile interior materials and housing building materials, The impact is also a concern.

JP 2002-285137 A

  Accordingly, an object of the present invention is to provide pressure-sensitive adhesive sheets having high adhesiveness, excellent terminal peeling prevention properties, and extremely low emission of formaldehyde and toluene.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that in the pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer made of a water-dispersible acrylic pressure-sensitive adhesive containing an emulsion containing a tackifying resin, Even if it is pressure sensitive adhesive sheets which have a pressure sensitive adhesive layer by an acrylic pressure sensitive adhesive by making the amount of diffusion and the amount of diffusion of toluene into a predetermined value, it has high adhesiveness and has an excellent terminal It has been found that the peeling prevention property can be exhibited and the amount of formaldehyde and toluene emitted can be reduced. The present invention has been completed based on these findings.

（式（１）において、Ｒ¹は水素原子又はメチル基、Ｒ²は炭素数２〜１４のアルキル基を示す）
で表される（メタ）アクリル酸アルキルエステルをモノマー主成分とする水分散型アクリル系重合体と、粘着付与樹脂を含有するエマルジョンとを含有する水分散型アクリル系粘着剤による粘着剤層を、少なくとも有している粘着シート類であって、前記粘着付与樹脂の軟化点が１２０℃以上、１７０℃以下であり、ホルムアルデヒドの放散量が３μｇ／ｍ³未満であり、且つトルエンの放散量が１０μｇ／ｇ以下であり、自動車用材料又は住宅用材料の固定の際に用いられることを特徴とする粘着シート類である。 That is, the present invention provides the following formula (1):

(In Formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 2 to 14 carbon atoms)
A pressure-sensitive adhesive layer made of a water-dispersed acrylic pressure-sensitive adhesive containing a water-dispersed acrylic polymer mainly composed of a (meth) acrylic acid alkyl ester represented by: and an emulsion containing a tackifying resin, The pressure-sensitive adhesive sheet has at least a softening point of the tackifying resin of 120 ° C. or higher and 170 ° C. or lower, a formaldehyde emission amount of less than 3 μg / m ³ , and a toluene emission amount of 10 μg. / g Ri der less, pressure-sensitive adhesive sheet, characterized in that used in the fixing material for automobiles or a material for residential buildings.

  In the pressure-sensitive adhesive sheets, the tackifier resin is preferably blended in an amount of 10 to 100 parts by weight with respect to 100 parts by weight of the acrylic polymer in the water-dispersed acrylic polymer. The thickness of the pressure-sensitive adhesive layer is, for example, 2 to 150 μm. The pressure-sensitive adhesive sheets may be double-sided pressure-sensitive adhesive sheets with a base material having pressure-sensitive adhesive layers on both surfaces of the base material. The pressure-sensitive adhesive sheets have, for example, an adhesive strength of 11 N / 20 mm or more with respect to a stainless steel (SUS) plate. The substrate may be a nonwoven fabric.

  According to the pressure-sensitive adhesive sheets of the present invention, the adhesive sheet has high adhesiveness and excellent terminal peeling resistance, and the amount of formaldehyde and toluene emitted is extremely small. Therefore, it is suitable as pressure-sensitive adhesive sheets used for fixing automobile materials or residential materials.

Fig.1 (a)-(f) is a schematic sectional drawing which respectively shows the example of the adhesive sheets of this invention.

  Embodiments of the present invention will be described below in detail with reference to the drawings as necessary. In addition, the same code | symbol may be attached | subjected to the same member, a site | part, etc.

As shown in FIG. 1, the pressure-sensitive adhesive sheet of the present invention has an emulsion containing a water-dispersed acrylic polymer and a tackifying resin (“tackifying resin-containing emulsion”) on at least one surface of a support. A water-dispersible acrylic pressure-sensitive adhesive layer (sometimes referred to as a “tackifying resin-containing pressure-sensitive adhesive layer”) and a formaldehyde The emission amount (formaldehyde emission amount) is less than 3 μg / m ³ and the toluene emission amount (toluene emission amount) is 10 μg / g or less. As described above, the pressure-sensitive adhesive sheets have the characteristics that the formaldehyde emission amount is less than 3 μg / m ³ and the toluene emission amount is 10 μg / g or less, and therefore the tackifying resin-containing emulsion is used. Nevertheless, formaldehyde and toluene emissions are greatly reduced. Of course, since a tackifying resin-containing emulsion is used, high adhesiveness and excellent terminal peeling prevention properties can be ensured. Therefore, in the pressure-sensitive adhesive sheets of the present invention, the amount of formaldehyde and toluene emitted can be effectively reduced while ensuring high adhesion and excellent terminal peeling prevention properties.

In the pressure-sensitive adhesive sheets of the present invention, the amount of formaldehyde emitted is not particularly limited as long as it is less than 3 μg / m ³ , and the lower the better. The amount of formaldehyde emitted is preferably 2 μg / m ³ or less (particularly 1 μg / m ³ or less). In addition, the value measured by the method based on JISA1901 (2003) is employ | adopted for the emission amount of formaldehyde. At this time, the surface area of the sample to be measured is 0.043 m ^2, and the formaldehyde content (μg / m ³ ) per unit volume of the sample (adhesive sheets) is calculated and quantified. Specific conditions are as follows.
Sampling conditions • Collection tube: “SEP-PAK DNPH Silica cartridge short type” manufactured by Waters
・ Flow rate: 167 mL / min
・ Amount collected: 10L
Measurement equipment, etc. ・ Small chamber: “20L chamber” manufactured by ADTEC
・ Clean air supply device: “ADclean” manufactured by Shinryo Eco Business Co., Ltd.
・ Seal material, seal box: None ・ Temperature and humidity controller: “ADPAC-SYSTEM III temperature and humidity unit” manufactured by ADTEC
・ Air collection device: "SP208-1000DUAL sampling pump" manufactured by GL Sciences Inc.
Analysis conditions ・ High performance liquid chromatograph: “TM996PAD” manufactured by Waters
・ Detector: UV Detector
Column: “Puresil C18 (4.6 × 150 mm)” manufactured by Waters
Mobile phase: acetonitrile aqueous solution (acetonitrile: water = 50: 50)
・ Injection volume: 20μL
・ Detection wavelength: 360 nm

Further, the amount of toluene diffused is not particularly limited as long as it is 10 μg / g or less, and the lower the better. The amount of toluene diffused is preferably 5 μg / g or less (particularly 3 μg / g or less). In addition, the value measured by the following [Toluene emission measuring method] is adopted as the emission of toluene.
[Toluene emission measurement method]
A predetermined size (area: 5 cm ² ) is cut from the adhesive sheet to prepare a sample, and the sample is put into a vial and sealed. Thereafter, the vial containing the sample is heated at 150 ° C. for 30 minutes by a headspace autosampler, and 1.0 ml of the heated gas is injected into a gas chromatograph measuring device (GC measuring device) to determine the amount of toluene. Measure, calculate and quantify the toluene content (μg / g) per unit weight of the sample (adhesive sheets). The measurement conditions for the gas chromatograph are as follows.
(Gas chromatograph measurement conditions)
Column: DB-FFAP 1.0 μm (0.535 mmφ × 30 m)
Carrier gas: He 5.0 mL / min
-Column head pressure: 23 kPa (40 ° C.)
・ Inlet: Split (split ratio 12: 1, temperature 250 ° C.)
Column temperature: 40 ° C. (0 min) − <+ 10 ° C./min>−250 (9 min) [After raising the temperature from 40 ° C. to 250 ° C. at a rate of temperature increase of 10 ° C./min, hold at 250 ° C. for 9 minutes. means]
-Detector: FID (temperature: 250 ° C)

  In addition, Fig.1 (a)-(f) is a schematic sectional drawing which respectively shows the example of the adhesive sheets of this invention. In FIG. 1, 11 to 16 are pressure-sensitive adhesive sheets, 2 is a base material, 3 is a tackifying resin-containing pressure-sensitive adhesive layer, and 4 is a release liner. The pressure-sensitive adhesive sheet 11 shown in FIG. 1 (a) has a structure in which a pressure-sensitive adhesive resin-containing pressure-sensitive adhesive layer 3 is formed on both surfaces of a base material 2 as a support, and both surfaces of a pressure-sensitive adhesive resin. Each of the contained pressure-sensitive adhesive layers 3 has a configuration protected by a release liner 4 having only one side as a release surface. Moreover, the pressure-sensitive adhesive sheets 12 shown in FIG. 1B have a configuration in which a tackifying resin-containing pressure-sensitive adhesive layer 3 is formed on both surfaces of a base material 2 as a support, and either one of them. The tackifying resin-containing pressure-sensitive adhesive layer 3 on the other side has a structure protected by a release liner 4 whose both surfaces are release surfaces, and the other side of the tackifying resin-containing pressure-sensitive adhesive layer 3 is By winding the adhesive sheets 12 in a roll shape, the other release surface of the release liner 4 can be protected.

  Moreover, the pressure-sensitive adhesive sheets 13 shown in FIG. 1C have a structure in which a pressure-sensitive adhesive resin-containing pressure-sensitive adhesive layer 3 is formed on one side of a base material 2 as a support, and the pressure-sensitive adhesive resin. The contained pressure-sensitive adhesive layer 3 has a configuration protected by a release liner 4 having only one side as a release surface. The pressure-sensitive adhesive sheets 14 shown in FIG. 1D have a configuration in which a tackifying resin-containing pressure-sensitive adhesive layer 3 is formed on one side of a base material 2 as a support, and a base as a support. The back surface of the material 2 is a release surface, and the tackifying resin-containing pressure-sensitive adhesive layer 3 is formed on the back surface of the base material 2 as a support by winding the pressure-sensitive adhesive sheet 14 in a roll shape. It can be set as the structure protected by the surface.

  Furthermore, the adhesive sheets 15 shown in FIG. 1 (e) are provided with a tackifying resin on one side of the release liner 4 as a support (one side on the release surface side of the release liner where only one side is the release surface). The pressure-sensitive adhesive layer 3 has a structure in which the pressure-sensitive adhesive layer 3 is formed, and the pressure-sensitive adhesive resin-containing pressure-sensitive adhesive layer 3 has a structure protected only by a release liner 4 on one side. The pressure-sensitive adhesive sheets 16 shown in FIG. 1 (f) have a structure in which a tackifier-resin-containing pressure-sensitive adhesive layer 3 is formed on one side of a release liner 4 (a release liner whose both surfaces are release surfaces) as a support. The tackifying resin-containing pressure-sensitive adhesive layer 3 is protected by the other release surface of the release liner 4 as a support by winding the pressure-sensitive adhesive sheet 16 in a roll shape. be able to.

  Thus, the pressure-sensitive adhesive sheets of the present invention need only have at least a tackifying resin-containing pressure-sensitive adhesive layer. For example, pressure-sensitive adhesive sheets having a base material (pressure-sensitive adhesive sheets with a base material), base Any of pressure-sensitive adhesive sheets (base material-less pressure-sensitive adhesive sheets) not having a material may be used. The pressure-sensitive adhesive sheets may be either double-sided pressure-sensitive adhesive sheets whose both surfaces are pressure-sensitive adhesive surfaces or pressure-sensitive adhesive sheets whose only one surface is a pressure-sensitive adhesive surface. When the pressure-sensitive adhesive sheets are substrate-less pressure-sensitive adhesive sheets, a support (for example, a release liner) capable of exhibiting releasability with respect to the tackifying resin-containing pressure-sensitive adhesive layer is used as the support. Can be used.

  Further, in the pressure-sensitive adhesive sheets of the present invention, the formaldehyde emission amount and the toluene emission amount are adjusted so as to have predetermined values. Therefore, the materials constituting the pressure-sensitive adhesive sheets (for example, containing a tackifying resin) It is important to use a material having a small content (or residual amount) of formaldehyde and toluene as a material constituting the pressure-sensitive adhesive layer or the base material. Since the pressure-sensitive adhesive sheets have at least a tackifying resin-containing pressure-sensitive adhesive layer, it is preferable to use a material having a low content of formaldehyde and toluene as a material constituting the tackifying resin-containing pressure-sensitive adhesive layer.

[Adhesive layer containing tackifying resin]
As described above, the tackifying resin-containing pressure-sensitive adhesive layer is formed of a water-dispersed acrylic pressure-sensitive adhesive containing a water-dispersed acrylic polymer and an emulsion containing a tackifying resin (tackifying resin-containing emulsion). Therefore, mainly formaldehyde and toluene may be contained in the tackifying resin-containing emulsion.

(Tackifying resin-containing emulsion)
In the tackifying resin-containing pressure-sensitive adhesive layer, the tackifying resin-containing emulsion is a tackifying resin composition in an emulsion form in which the tackifying resin is dispersed in water. The tackifying resin is not particularly limited. For example, rosin tackifying resin, terpene tackifying resin, hydrocarbon tackifying resin, epoxy tackifying resin, polyamide tackifying resin, elastomer tackifying resin, Examples thereof include phenolic tackifier resins and ketone tackifier resins. Tackifying resins can be used alone or in combination of two or more.

  Specifically, as the rosin-based tackifying resin, for example, unmodified rosin (raw rosin) such as gum rosin, wood rosin, tall oil rosin, and hydrogenation, disproportionation, polymerization, etc. of these unmodified rosins. In addition to modified rosins (hydrogenated rosin, disproportionated rosin, polymerized rosin, and other chemically modified rosins), various rosin derivatives and the like can be mentioned. Examples of the rosin derivative include rosin ester compounds obtained by esterifying unmodified rosin with alcohols, and modified rosin esters obtained by esterifying modified rosins such as hydrogenated rosin, disproportionated rosin and polymerized rosin with alcohols. Rosin esters such as compounds; Unmodified rosin and modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.) modified with unsaturated fatty acids; Unsaturated fatty acid modified rosins; Rosin esters modified with unsaturated fatty acids Unsaturated rosin, modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.), unsaturated fatty acid modified rosins and unsaturated fatty acid modified rosin esters Rosin alcohols such as unmodified rosin, modified rosin and various rosin derivatives Oxazines (especially, rosin esters) and the like metal salts of. In addition, as the rosin derivative, a rosin phenol resin obtained by adding phenol to an rosin (unmodified rosin, modified rosin, various rosin derivatives, etc.) with an acid catalyst and thermal polymerization can be used.

  Examples of terpene-based tackifier resins include terpene resins such as α-pinene polymers, β-pinene polymers, dipentene polymers, and modified terpene resins (phenol-modified, aromatic-modified, hydrogenated-modified). And modified terpene resins such as terpene-phenol resins, styrene modified terpene resins, aromatic modified terpene resins, hydrogenated terpene resins, and the like.

  Examples of hydrocarbon-based tackifying resins include aliphatic hydrocarbon resins [olefins having 4 to 5 carbon atoms and dienes (olefins such as butene-1, isobutylene, pentene-1; butadiene, 1,3-pentadiene, isoprene). Polymers of aliphatic hydrocarbons such as diene etc.], aromatic hydrocarbon resins [vinyl group-containing aromatic hydrocarbons having 8 to 10 carbon atoms (styrene, vinyl toluene, α-methylstyrene) , Indene, methylindene, etc.)], and aliphatic cyclic hydrocarbon resins [so-called “C4 petroleum fraction” and “C5 petroleum fraction” after cyclization and dimerization and polymerization. Hydrocarbon resins, cyclic diene compounds (cyclopentadiene, dicyclopentadiene, ethylidene norbornene, dipentene, etc.) polymers or hydrogenated products thereof, Aromatic hydrocarbon resins, alicyclic hydrocarbon resins obtained by hydrogenating aromatic rings of aliphatic / aromatic petroleum resins, etc.], aliphatic / aromatic petroleum resins (styrene-olefin copolymers, etc.) And various hydrocarbon resins such as aliphatic / alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, coumarone indene resins, and the like.

  Tackifying resins include a softening point (softening temperature) to reduce the amount of formaldehyde and toluene emitted from the pressure-sensitive adhesive sheets, and to make the pressure-sensitive adhesive sheets exhibit high adhesion, excellent terminal peeling resistance, and heat resistance. ) Is 120 ° C. or higher (preferably 130 ° C. or higher, more preferably 140 ° C. or higher). In addition, as an upper limit of the softening point of tackifying resin, it is 170 degrees C or less (preferably 160 degrees C or less, More preferably, it is 155 degrees C or less).

  The softening point of the tackifying resin is defined as a value measured by the ring and ball method defined in JIS K 5902. Specifically, the sample is melted as quickly as possible, and this is carefully filled in a ring placed on a flat metal plate so as not to cause bubbles. After cooling, cut off the raised part from the plane including the top of the ring with a slightly heated sword. Next, a supporter is put in a glass container (diameter: 85 mm or more, height: 127 mm or more), and water that has been boiled in advance and then cooled is poured to a depth of 90 mm or more. Next, the steel ball (diameter 9.5 mm, weight 3.5 g) and the ring filled with the sample are immersed in water so as not to contact each other, and the temperature of the water is kept at 20 ° C. plus or minus 5 ° C. for 15 minutes. Next, a steel ball is placed on the center of the surface of the sample in the ring, and this is placed in a fixed position on the support. Next, the distance from the upper end of the ring to the water surface is maintained at 50 mm, a thermometer is placed, the position of the center of the mercury bulb of the thermometer is set to the same height as the center of the ring, and the container is heated. The flame of the Bunsen burner used for heating is placed between the center and the edge of the bottom of the container so that the heating is even. It should be noted that the rate at which the water temperature increases after reaching 40 ° C. after heating has started must be 5.0 plus or minus 0.5 ° C. per minute. The temperature at the time when the sample gradually softens and flows down from the ring and finally comes into contact with the bottom plate is read and used as the softening point. Two or more softening points are measured simultaneously, and the average value is adopted.

In particular, as a tackifier resin, a tackifier resin in which formaldehyde is not used can be suitably used as a material (or a raw material) for producing the tackifier resin. In the tackifying resin, as the tackifying resin in which formaldehyde is not used as a material or raw material, for example, rosin-based tackifying resin, terpene-based tackifying resin, hydrocarbon-based tackifying resin, epoxy-based tackifying resin, polyamide-based Examples include tackifying resins and elastomeric tackifying resins. Thus, the amount of formaldehyde released in the pressure-sensitive adhesive sheets having the pressure-sensitive adhesive resin-containing pressure-sensitive adhesive layer by using the pressure-sensitive adhesive resin in which formaldehyde is not used as the material (or raw material) as the pressure-sensitive adhesive resin (Content) can be controlled to be less than 3 μg / m ³ .

The tackifying resin-containing emulsion can be prepared by dispersing the tackifying resin in water. At this time, the tackifying resin-containing emulsion is usually prepared by dissolving or melting the tackifying resin and then dispersing it in water. When the tackifying resin is a tackifying resin having a low softening point, the tackifying resin-containing emulsion can be prepared by melting the tackifying resin by heating and then dispersing it in water. On the other hand, when the tackifying resin is a tackifying resin having a high softening point, the tackifying resin-containing emulsion is a method of melting the tackifying resin under high temperature and high pressure without using any organic solvent, aromatic carbonization. It is preferable to prepare by dissolving or melting the tackifier resin using a method for dissolving or melting the tackifier resin such as a method of dissolving using a material other than the hydrogen-based organic solvent, and then dispersing it in water. As described above, when the tackifying resin is dissolved or melted, the pressure-sensitive adhesive sheet having the tackifying resin-containing pressure-sensitive adhesive layer is finally obtained by using the method for dissolving or melting the tackifying resin as described above. The formaldehyde emissions (contents) and toluene emissions (contents) can be controlled to be less than 3 μg / m ³ and 10 μg / g or less, respectively.

  Examples of the method for emulsifying the tackifying resin without using an organic solvent at all include a solventless high-pressure emulsification method and a solventless phase inversion emulsification method. The solventless high-pressure emulsification method is a method in which a tackifying resin is heated above its softening point, in a molten state, premixed with water and a suitable emulsifier, and emulsified with a high-pressure emulsifier to emulsify. Is the method. The solventless phase inversion emulsification method means that under pressure or normal pressure, the temperature is raised above the softening point of the tackifier resin, and the emulsifier is kneaded, and hot water is gradually added. And emulsifying.

  Further, in the method of dissolving or melting the tackifying resin using a material other than the aromatic hydrocarbon-based organic solvent, the material other than the aromatic hydrocarbon-based organic solvent may be appropriately selected according to the type of the tackifying resin. An alicyclic hydrocarbon-based organic solvent can be suitably used. Examples of such alicyclic hydrocarbon-based organic solvents include cyclohexanes (cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, alkyl group-containing cyclohexane such as methylethylcyclohexane, etc.), and other cyclohexanes. And cyclopentanes (such as cyclopentane and alkyl group-containing cyclopentane), cycloheptanes (such as cycloheptane and alkyl group-containing cycloheptane), and cyclooctanes (such as cyclooctane and alkyl group-containing cyclooctane). In addition, organic solvents, such as an alicyclic hydrocarbon type organic solvent, can be used individually or in mixture of 2 or more types.

  The amount of the organic solvent such as the alicyclic hydrocarbon-based organic solvent is not particularly limited, but the tackifier resin can be dissolved or melted and dispersed in water using an emulsifier as necessary. Any amount may be used, but it is preferable that the amount is as small as possible. It is important to remove the organic solvent as much as possible after preparing the tackifying resin-containing emulsion by a known or conventional removal method (for example, a vacuum distillation method or the like).

  In the present invention, when preparing the tackifying resin-containing emulsion, an emulsifier can be used when the tackifying resin is dispersed in water. As the emulsifier, one or more of the emulsifiers exemplified below can be appropriately selected and used as the emulsifier used when preparing the water-dispersed acrylic polymer. Specifically, as the emulsifier, for example, any form of emulsifier may be used, but an anionic emulsifier and a nonionic emulsifier can be suitably used. Examples of the anionic emulsifier include alkyl sulfate anion emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, and potassium lauryl sulfate; polyoxyethylene alkyl ether sulfate anion emulsifiers such as sodium polyoxyethylene lauryl ether sulfate; Polyoxyethylene alkylphenyl ether sulfate-type anionic emulsifiers such as ammonium oxyethylene lauryl phenyl ether sulfate and sodium polyoxyethylene lauryl phenyl ether sulfate; Sulfonate-type anionic emulsifiers such as sodium dodecylbenzenesulfonate; Disodium lauryl sulfosuccinate And a sulfosuccinic acid type anionic emulsifier such as polyoxyethylene sulfosuccinate disodium lauryl. Nonionic emulsifiers include, for example, polyoxyethylene alkyl ether type nonionic emulsifiers such as polyoxyethylene lauryl ether; polyoxyethylene alkylphenyl ether type nonionic emulsifiers such as polyoxyethylene lauryl phenyl ether; polyoxyethylene fatty acids Nonionic emulsifiers such as esters and polyoxyethylene polyoxypropylene block polymers are listed.

  In addition, the emulsifier when preparing the water-dispersed acrylic polymer and the emulsifier when preparing the tackifier resin-containing emulsion may be either the same emulsifier or different emulsifiers. If it is an anionic emulsifier, the other is preferably an anionic emulsifier, and if one is a nonionic emulsifier, the other is also preferably a nonionic emulsifier.

  The amount of the emulsifier used is not particularly limited as long as it is an amount that can be used to prepare the tackifying resin in the form of an emulsion. For example, 0.2 to 10% by weight with respect to the total amount of the tackifying resin (solid content). % (Preferably 0.5 to 5% by weight).

  Examples of the tackifying resin-containing emulsion include, for example, trade name “SK-253NS” (manufactured by Harima Chemicals Co., Ltd .; softening point 145 ° C .; tackifying resin-containing emulsion manufactured without using any organic solvent) or , Trade name “Tamanol E-200-NT” (manufactured by Arakawa Chemical Co., Ltd .; softening point 150 ° C .; tackifying resin-containing emulsion produced using an alicyclic hydrocarbon-based organic solvent) and the like can be used.

(Water-dispersed acrylic polymer)
In the tackifying resin-containing pressure-sensitive adhesive layer, the water-dispersed acrylic polymer is an emulsion-based acrylic polymer composition in which the acrylic polymer is dispersed in water. The acrylic polymer is used as a base polymer of the pressure-sensitive adhesive (basic component of the pressure-sensitive adhesive). In the acrylic polymer, (meth) acrylic acid alkyl ester (acrylic acid alkyl ester, methacrylic acid alkyl ester) is used as the main constituent monomer component (monomer main component). The alkyl (meth) acrylate is represented by the above formula (1).

In the above formula (1), R ¹ is a hydrogen atom or a methyl group. R ² is an alkyl group having 2 to 14 carbon atoms. Specifically, examples of the alkyl group for R ² include ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, pentyl, isoamyl, neopentyl, and hexyl. Alkyl groups having 2 to 14 carbon atoms such as a group, heptyl group, octyl group, isooctyl group, 2-ethylhexyl group, nonyl group, isononyl group, decyl group, isodecyl group, undecyl group, dodecyl group, tridecyl group and tetradecyl group Etc. As the alkyl group for R ² , an alkyl group having 2 to 10 carbon atoms (in particular, a butyl group or a 2-ethylhexyl group) is particularly preferable.

  Specifically, examples of the (meth) acrylic acid alkyl ester include, for example, butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, ( Pentyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, (Meth) acrylic acid nonyl, (meth) acrylic acid isononyl, (meth) acrylic acid decyl, (meth) acrylic acid isodecyl, (meth) acrylic acid undecyl, (meth) acrylic acid dodecyl etc. are mentioned.

  The (meth) acrylic acid alkyl ester can be used alone or in combination of two or more. As (meth) acrylic acid alkyl ester, for example, butyl acrylate may be used alone, or butyl acrylate and 2-ethylhexyl acrylate may be used in combination. In addition, as a (meth) acrylic acid alkyl ester, when butyl acrylate is used alone or in combination with butyl acrylate and 2-ethylhexyl acrylate, the ratio between butyl acrylate and 2-ethylhexyl acrylate is as follows: Although not particularly limited, for example, it can be selected from the range of 2-ethylhexyl acrylate / butyl acrylate (weight ratio) = 0/100 to 55/45 (preferably 5/95 to 60/40).

  As the monomer component constituting the acrylic polymer, other monomer components that can be copolymerized with (meth) acrylic acid alkyl ester (“copolymerizable monomer”) can be used as long as (meth) acrylic acid alkyl ester is the main monomer component. May be referred to as “components”). In addition, as a ratio of the (meth) acrylic acid alkyl ester to the total amount of monomer components constituting the acrylic polymer, it is 80% by weight or more (for example, 80 to 99.8% by weight), preferably 85% by weight or more (for example, 85 to 99.5% by weight), more preferably 90% or more (90 to 99% by weight).

  As the copolymerizable monomer component, it can be used for introducing a crosslinking point into the acrylic polymer or for increasing the cohesive force of the acrylic polymer. The copolymerizable monomer components can be used alone or in combination of two or more.

  Specifically, as the copolymerizable monomer component, a functional group-containing monomer component (particularly, heat for introducing a crosslinking point that is thermally crosslinked to the acrylic polymer) is introduced in order to introduce a crosslinking point into the acrylic polymer. Crosslinkable functional group-containing monomer component) can be used. By using the functional group-containing monomer component, it is possible to improve the adhesion to the adherend. Such a functional group-containing monomer component is not particularly limited as long as it is a monomer component that can be copolymerized with a (meth) acrylic acid alkyl ester and has a functional group that becomes a crosslinking point. (Meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, isocrotonic acid and other carboxyl group-containing monomers or acid anhydrides thereof (maleic anhydride, itaconic anhydride, etc.); (meth) acrylic acid 2-hydroxy Hydroxyalkyl (meth) acrylates such as ethyl, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, etc., and hydroxyl-containing monomers such as vinyl alcohol and allyl alcohol; (meth) acrylamide, N , N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, -Amide monomers such as methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide; aminoethyl (meth) acrylate, (meth) Amino group-containing monomers such as N, N-dimethylaminoethyl acrylate and t-butylaminoethyl (meth) acrylate; Epoxy group-containing monomers such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate; acrylonitrile; Cyano-containing monomers such as methacrylonitrile; N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinyl Roll, N- vinylimidazole, N- vinyloxazole, N- vinyl morpholine, N- vinyl caprolactam, such a monomer having a nitrogen atom-containing ring such as N- (meth) acryloyl morpholine. As the functional group-containing monomer component, a carboxyl group-containing monomer such as acrylic acid or an acid anhydride thereof can be suitably used.

  The amount of the functional group-containing monomer component used is, for example, (meth) acrylic acid alkyl ester as a monomer main component: 12 parts by weight or less (for example, 0.5 to 12 parts by weight, preferably 1 with respect to 100 parts by weight) -8 parts by weight).

  Further, as the copolymerizable monomer component, other copolymerizable monomer components can be used in order to increase the cohesive strength of the acrylic polymer. Other copolymerizable monomer components include, for example, vinyl ester monomers such as vinyl acetate and vinyl propionate; styrene monomers such as styrene, substituted styrene (α-methylstyrene, etc.) and vinyltoluene; (meth) acrylic acid Non-aromatic ring-containing (meth) acrylate esters such as cycloalkyl esters [cyclohexyl (meth) acrylate, cyclopentyl di (meth) acrylate, etc.] and isobornyl (meth) acrylate; (meth) acrylate aryl esters [ Fragrances such as (meth) acrylic acid phenyl etc.], (meth) acrylic acid aryloxyalkyl esters [(meth) acrylic acid phenoxyethyl etc.] and (meth) acrylic acid arylalkyl esters [(meth) acrylic acid benzyl ester] Aromatic ring content (meta) Crylic acid esters; Olefin-based monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene; Vinyl chloride, vinylidene chloride; Isocyanate group-containing monomers such as 2- (meth) acryloyloxyethyl isocyanate; Methoxyethyl (meth) acrylate, ( Alkoxy group-containing monomers such as methacrylic acid ethoxyethyl; vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether, 1,6-hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) ) Acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate , Propylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol Multifunctional monomers such as tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerin di (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, divinylbenzene, butyl di (meth) acrylate, hexyl di (meth) acrylate Etc.

  As a polymerization method for the water-dispersed acrylic polymer, a known or conventional polymerization method can be employed, and an emulsion polymerization method is preferable. In the polymerization, various polymerization methods such as a general batch charging method (batch polymerization method) and a monomer dropping method (continuous dropping method, divided dropping method, etc.) can be employed. The polymerization temperature can be appropriately selected according to the type of monomer, the type of polymerization initiator, and the like, and can be selected from the range of 20 to 100 ° C., for example.

  As a polymerization initiator used at the time of superposition | polymerization, it can select suitably from well-known thru | or a usual polymerization initiator according to the kind of polymerization method. Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (2-amidinopropane) dihydro Chloride, 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (N, N'-dimethyleneisobutylamidine), 2,2 '-Azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylbutyronitrile), 1, 1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis (2,4,4-trimethylpentane), dimethyl-2,2'-azobis (2-methylpropiyl) Azo polymerization initiators such as sulfonates; persulfates such as potassium persulfate and ammonium persulfate; benzoyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-butyl peroxybenzoate, dicumylper Start of peroxide polymerization of oxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, hydrogen peroxide, etc. Agents: Substituted ethane polymerization initiators such as phenyl-substituted ethanes; aromatic carbonyl compounds; redox initiators in combination with peroxides and reducing agents [for example, combinations of peroxides and ascorbic acid (hydrogen peroxide water And a combination of peroxide and iron (II) salt (hydrogen peroxide water and the like) (II) a combination with a salt), a redox polymerization initiator by a combination of a persulfate and sodium bisulfite, etc.] The polymerization initiators can be used alone or in combination of two or more. .

  The usage-amount of a polymerization initiator should just be a normal usage-amount, for example, can be selected from the range of about 0.005-1 weight part with respect to 100 weight part of all monomer components.

  In the polymerization, a chain transfer agent can be used to adjust the molecular weight. As the chain transfer agent, known or conventional chain transfer agents can be used. For example, dodecanethiol (lauryl mercaptan), glycidyl mercaptan, 2-mercaptoethanol, mercaptoacetic acid, 2-ethylhexyl thioglycolate, 2,3- In addition to mercaptans such as dimethylcapto-1-propanol, α-methylstyrene dimer and the like can be mentioned. A chain transfer agent can be used individually or in combination of 2 or more types. The usage amount of the chain transfer agent may be a normal usage amount, and can be selected, for example, from a range of about 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the total monomer components.

  Since the water-dispersed acrylic polymer has the form of an emulsion, the water-dispersed acrylic polymer is prepared using the emulsion-form polymer prepared by using the emulsion polymerization method as it is. Alternatively, the water-dispersed acrylic polymer may be prepared by dispersing an acrylic polymer prepared by using a polymerization method other than the emulsion polymerization method in water. An emulsifier can be used during emulsion polymerization or when the acrylic polymer is dispersed in water. An emulsifier can be used individually or in combination of 2 or more types.

  Specifically, as the emulsifier, for example, any form of emulsifier may be used, but an anionic emulsifier and a nonionic emulsifier can be suitably used. Examples of the anionic emulsifier include alkyl sulfate anion emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, and potassium lauryl sulfate; polyoxyethylene alkyl ether sulfate anion emulsifiers such as sodium polyoxyethylene lauryl ether sulfate; Polyoxyethylene alkylphenyl ether sulfate-type anionic emulsifiers such as ammonium oxyethylene lauryl phenyl ether sulfate and sodium polyoxyethylene lauryl phenyl ether sulfate; Sulfonate-type anionic emulsifiers such as sodium dodecylbenzenesulfonate; Disodium lauryl sulfosuccinate And a sulfosuccinic acid type anionic emulsifier such as polyoxyethylene sulfosuccinate disodium lauryl. Nonionic emulsifiers include, for example, polyoxyethylene alkyl ether type nonionic emulsifiers such as polyoxyethylene lauryl ether; polyoxyethylene alkylphenyl ether type nonionic emulsifiers such as polyoxyethylene lauryl phenyl ether; polyoxyethylene fatty acids Nonionic emulsifiers such as esters and polyoxyethylene polyoxypropylene block polymers are listed.

  The amount of the emulsifier is not particularly limited as long as it is an amount that can prepare the acrylic polymer in the form of an emulsion. For example, the amount of the emulsifier is 0.2 to 10 with respect to the total amount of the acrylic polymer or the monomer component. It can be selected from the range of about wt% (preferably 0.5 to 5 wt%).

  In the tackifier resin-containing emulsion, the amount of the tackifier resin used is not particularly limited, and can be appropriately set according to the purpose of imparting the desired tackiness or imparting terminal peeling prevention property. As the tackifying resin-containing emulsion, the tackifying resin in the tackifying resin-containing emulsion is 10 to 100 parts by weight (preferably 15 to 100 parts by weight with respect to 100 parts by weight of the acrylic polymer in the water-dispersed acrylic polymer). 80 parts by weight, more preferably 20 to 60 parts by weight). The tackifying resin-containing emulsion is blended in a blending amount such that the tackifying resin in the tackifying resin-containing emulsion is less than 10 parts by weight with respect to 100 parts by weight of the acrylic polymer in the water-dispersed acrylic polymer. If it is, the addition effect of the tackifying resin is not sufficient, the target adhesive strength can not be obtained, the terminal peeling prevention property is lowered, on the other hand, the blending amount exceeds 100 parts by weight In this case, the residual amount of the organic solvent increases, and the adhesive strength may decrease due to poor compatibility with the acrylic polymer.

(Other ingredients)
A cross-linking agent may be used in the water-dispersed acrylic pressure-sensitive adhesive for forming the tackifying resin-containing pressure-sensitive adhesive layer, if necessary. The crosslinking agent is not particularly limited, and is a known or conventional crosslinking agent (for example, an isocyanate crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, a melamine crosslinking agent, a peroxide crosslinking agent). , Urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, carbodiimide crosslinking agents, amine crosslinking agents, etc.). The crosslinking agent may be either an oil-soluble crosslinking agent or a water-soluble crosslinking agent. A crosslinking agent can be used individually or in combination of 2 or more types. The amount of the crosslinking agent used is not particularly limited. For example, the acrylic polymer in the water-dispersed acrylic polymer: 10 parts by weight or less (for example, 0.005 to 10 parts by weight, Preferably, it can select from the range of about 0.01-5 weight part).

  In addition, the water-dispersed acrylic pressure-sensitive adhesive for forming the tackifying resin-containing pressure-sensitive adhesive layer may contain other additives (for example, anti-aging agents, ultraviolet absorbers, antioxidants, light stabilizers) as necessary. Agents, release modifiers, plasticizers, softeners, fillers, colorants (pigments, dyes, etc.), surfactants, antistatic agents, etc.) and bases for adjusting the pH (Ammonia water or the like) or acid may be contained.

  The tackifying resin-containing pressure-sensitive adhesive layer is prepared by mixing or kneading the above components (water-dispersed acrylic polymer, tackifying resin-containing emulsion, as well as cross-linking agents and various additives as necessary) in predetermined amounts. It can form by apply | coating the water-dispersed acrylic adhesive prepared by this on a predetermined surface, and making it dry or harden | cure. A conventional coater (for example, a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, or a spray coater) can be used for applying the water-dispersed acrylic pressure-sensitive adhesive.

  The thickness of the tackifying resin-containing pressure-sensitive adhesive layer can be selected, for example, from the range of 2 to 150 μm (preferably 5 to 100 μm), and particularly preferably 2 to 50 μm (among others, 2 to 20 μm). is there.

[Support]
In the pressure-sensitive adhesive sheets of the present invention, a substrate or a release liner can be suitably used as the support. As described above, when the support is a base material, the pressure-sensitive adhesive sheets are pressure-sensitive adhesive sheets with a base material, and when the support is not a base material but a release liner, the pressure-sensitive adhesive sheets are base-less. Adhesive sheets. Therefore, the release liner [for example, the release liner 4 in FIGS. 1A to 1C] in the pressure-sensitive adhesive sheet with a substrate is not included in the support, but the release liner in the substrate-less pressure-sensitive adhesive sheet [ For example, the release liner 4 in FIGS. 1E and 1F] is included in the support. Thus, the release liner as a support can protect the surface of the tackifying resin-containing pressure-sensitive adhesive layer while supporting the laminate of the tackifying resin-containing pressure-sensitive adhesive layer.

  In the support, examples of the substrate include a polyolefin sheet or film (polyethylene sheet or film, polypropylene sheet or film, ethylene-propylene copolymer sheet or film, etc.), polyester sheet or film (polyethylene terephthalate). Sheet or film), vinyl chloride resin sheet or film, vinyl acetate resin sheet or film, polyimide resin sheet or film, polyamide resin sheet or film, fluororesin sheet or film, cellophane Plastic sheets or films such as Japanese paper, kraft paper, glassine paper, fine paper, synthetic paper, top coat paper, etc .; cotton fiber, sufu, manila hemp, pulp, rayon, acetate fiber, polyester Textile, polyvinyl alcohol fiber, polyamide fiber, polyolefin fiber and other natural fibers, semi-synthetic fibers or synthetic fiber fibrous materials such as single or mixed woven fabrics and non-woven fabrics; natural rubber, butyl rubber, etc. Examples include rubber sheets; foam sheets made of a foam made of polyurethane, polychloroprene rubber, etc .; metal foils such as aluminum foil and copper foil; and composites thereof. The plastic sheet or film may be either a non-stretching type or a stretching type (uniaxial stretching type or biaxial stretching type). The substrate may have a single layer form or may have a laminated form.

  In addition, for the base material, fillers (inorganic fillers, organic fillers, etc.), anti-aging agents, antioxidants, ultraviolet absorbers, lubricants, plasticizers, colorants (pigments, dyes, etc.) as necessary Various additives such as these may be blended.

  For the surface of the base material (particularly the surface on the polymer layer side), for example, appropriate known or conventional surface treatment such as physical treatment such as corona discharge treatment or plasma treatment, chemical treatment such as undercoating treatment or back treatment. May be given.

  Although the thickness of a base material can be suitably selected according to the objective, Generally, it is about 10-200 micrometers (preferably 20-100 micrometers).

(Release liner)
In the support, the release liner is not particularly limited and can be appropriately selected from known release liners. As the release liner, a substrate having a release treatment layer with a release treatment agent on at least one surface can be suitably used, and a fluorine-based polymer (for example, polytetrafluoroethylene, polychlorotrifluoroethylene, polyfluorination) Low adhesion substrates made of vinyl, polyvinylidene fluoride, tetrafluoroethylene / hexafluoropropylene copolymer, chlorofluoroethylene / vinylidene fluoride copolymer, etc., and nonpolar polymers (eg, olefins such as polyethylene and polypropylene) A low-adhesive base material made of a resin or the like can also be used.

  As the base material of the release liner, a plastic sheet or a film is suitably used, but the paper, cloth, rubber sheet, foam sheet, metal foil, etc. exemplified as the base material as the support should also be used. Can do. The plastic sheet or film as the base material of the release liner is not particularly limited, and can be appropriately selected from, for example, the plastic sheets or films exemplified as the base material as the support.

  As the release treatment agent for forming the release treatment layer, a known or commonly used release treatment agent (silicone release treatment agent, fluorine release treatment agent, long-chain alkyl release treatment agent, etc.) can be used.

  The thickness of the base material or the release treatment layer in the release liner is not particularly limited, and can be appropriately selected according to the purpose. The total thickness of the release liner is, for example, preferably 15 μm or more, and more preferably 25 to 500 μm.

  The release liner in the substrate-less pressure-sensitive adhesive sheets can be appropriately selected from the release liners exemplified as the release liner as the support. The release liner that protects the surface of the tackifying resin-containing pressure-sensitive adhesive layer and the release liner as the support may be release liners having the same configuration or release liners having different configurations.

[Adhesive sheets]
In the present invention, the pressure-sensitive adhesive sheet means a sheet-like pressure-sensitive adhesive material having or having a form of a sheet-like material having a pressure-sensitive adhesive layer. Specifically, the adhesive sheets include an adhesive tape, an adhesive sheet, an adhesive film, an adhesive label, and the like.

  The pressure-sensitive adhesive sheet has other layers (for example, an intermediate layer, an undercoat layer, etc.) as long as it has a tackifying resin-containing pressure-sensitive adhesive layer as long as the effects of the present invention are not impaired. May be.

  Such pressure-sensitive adhesive sheets can be manufactured according to a normal pressure-sensitive adhesive tape or pressure-sensitive adhesive sheet manufacturing method according to the type of pressure-sensitive adhesive sheets. Specifically, when the pressure-sensitive adhesive sheets are of a type with a base material, the type of pressure-sensitive adhesive sheet with a base material is, for example, (1) water-dispersed acrylic on at least one side (one side or both sides) of the base material. A water-dispersed acrylic pressure-sensitive adhesive containing a polymer and a tackifying resin-containing emulsion is applied and dried so that the thickness after drying becomes a predetermined thickness, thereby forming a pressure-sensitive adhesive-containing pressure-sensitive adhesive layer (2) A water-dispersed acrylic pressure-sensitive adhesive containing a water-dispersed acrylic polymer and a tackifying resin-containing emulsion on a separator is dried to a predetermined thickness. After forming the tackifying resin-containing pressure-sensitive adhesive layer so as to form a pressure-sensitive adhesive layer, the pressure-sensitive adhesive resin-containing pressure-sensitive adhesive layer is transferred to at least one side (one side or both sides) of the substrate. How to More, it can be produced.

  On the other hand, when the pressure-sensitive adhesive sheet is a substrate-less type, the substrate-less type pressure-sensitive adhesive sheet is, for example, (1) at least one release surface of a release liner (a surface of a release treatment layer or a low-adhesive substrate). A water-dispersed acrylic pressure-sensitive adhesive containing a water-dispersed acrylic polymer and a tackifying resin-containing emulsion is applied on the surface, etc., and dried to a predetermined thickness. It can be produced by a method of producing by forming a tackifying resin-containing pressure-sensitive adhesive layer.

  In the pressure-sensitive adhesive sheets shown in FIGS. 1B, 1D, and 1F, the pressure-sensitive adhesive surface on one side of the pressure-sensitive adhesive sheet (the surface of the pressure-sensitive adhesive resin-containing pressure-sensitive adhesive layer) and the other side. To produce pressure-sensitive adhesive sheets wound in a roll shape by overlapping the release surface (the back treatment layer surface of the substrate, the release treatment layer surface of the release liner, etc.) and winding them into a roll shape. Can do.

  In addition, when forming a tackifier resin-containing pressure-sensitive adhesive layer, when crosslinking is performed, the type of the crosslinking agent (for example, a thermal crosslinking type crosslinking agent that is crosslinked by heating, a photocrosslinking type crosslinking agent that is crosslinked by ultraviolet irradiation, etc. ), The crosslinking can be performed by a known or conventional crosslinking method in a predetermined production process. For example, when the crosslinking agent used is a thermal crosslinking type crosslinking agent, the thermal crosslinking reaction is performed in parallel with or simultaneously with the drying when the water-dispersed acrylic pressure-sensitive adhesive is applied and then dried. It can proceed to crosslink. Specifically, depending on the type of thermal crosslinking type crosslinking agent, crosslinking can be performed together with drying by heating to a temperature equal to or higher than the temperature at which the crosslinking reaction proceeds.

  In the present invention, when the water-dispersed acrylic pressure-sensitive adhesive is applied and then dried, it is preferable to strengthen the drying as much as possible. Thus, when drying is strengthened, organic solvents such as formaldehyde and toluene remaining in the pressure-sensitive adhesive sheets or the pressure-sensitive adhesive layer containing the tackifying resin can be further reduced, and organic substances such as formaldehyde and toluene can be reduced. It is possible to obtain pressure-sensitive adhesive sheets in which the amount of solvent emitted is further reduced.

  When the tackifying resin-containing pressure-sensitive adhesive layer is formed by cross-linking, the ratio of the solvent-insoluble matter (cross-linked acrylic polymer) in the tackifying resin-containing pressure-sensitive adhesive layer is not particularly limited. It is desirable that the amount is about 15 to 70% by weight with respect to the total solid content in the layer. In this case, the acrylic polymer having a solvent-soluble content in the tackifying resin-containing pressure-sensitive adhesive layer has a weight average molecular weight (polystyrene conversion, analyzer: “HLC-8120GPC” manufactured by TOSOH, column: “TSKgel GMH- H (S) ") is desirably 100,000 to 600,000 (preferably 200,000 to 450,000).

  In addition, the ratio of the crosslinked body of the acrylic polymer as the solvent-insoluble content after crosslinking and the molecular weight (weight average molecular weight) of the acrylic polymer as the solvent-soluble content are, for example, functional group-containing monomers with respect to the total amount of the monomer components. It can be arbitrarily set by appropriately adjusting the component ratio, the type and ratio of the chain transfer agent, the type and ratio of the crosslinking agent, and the like.

  The pressure-sensitive adhesive sheets of the present invention have high adhesiveness and excellent terminal peeling prevention properties, and since the amount of formaldehyde and toluene emitted is extremely small, automotive materials such as automotive interior materials, housing building materials, etc. Even if it is used in a closed space such as a housing material, the influence on the human body can be reduced. Therefore, the pressure-sensitive adhesive sheets of the present invention can be suitably used for fixing automobile materials or residential materials.

Examples of the present invention will be described below in more detail. In the following, “parts” means “parts by weight”, and “%” means “% by weight”.
Example 3 is described as a reference example.

Example 1
Using a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, butyl acrylate: 90 parts, 2-ethylhexyl acrylate: 10 parts, acrylic acid: 4 parts, dodecanethiol (chain transfer agent): 0 .05 parts, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride (polymerization initiator): 0.1 part of sodium polyoxyethylene lauryl sulfate (emulsifier) ): In addition to 100 parts of water to which 2 parts were added, the reaction vessel was charged and heated to 60 ° C. while stirring and subjected to an emulsion polymerization reaction at 60 ° C. for 4 hours, and then aged for 2 hours. A reaction mixture containing an acrylic polymer was obtained.

  To the reaction mixture, 10% aqueous ammonia was added to adjust the pH to 7, and subsequently, a water-soluble oxazoline-based crosslinking agent (oxazoline-type crosslinking agent) dissolved in water (trade name “Epocross WS-”). 500 ”(manufactured by Nippon Shokubai Chemical Co., Ltd.) was added to obtain an aqueous dispersion of an acrylic polymer (water-dispersed acrylic polymer).

  For the water-dispersed acrylic polymer, 100 parts (solid content) of the water-dispersed acrylic polymer, an emulsion containing a tackifying resin, trade name “SK-253NS” (manufactured by Harima Chemical Co., Ltd.) Softening point 145 ° C .; polymerized rosin resin) was added in an amount of 30 parts in terms of solid content to obtain a water-dispersed pressure-sensitive adhesive (water-dispersed acrylic pressure-sensitive adhesive) containing a tackifier resin. The trade name “SK-253NS” is a tackifying resin-containing emulsion produced without using any organic solvent.

  This water-dispersed acrylic pressure-sensitive adhesive was applied to the surface of a release treatment layer of a release liner (trade name “SLB-80WD (V2)” manufactured by Kite Chemical Industries, Ltd.) having a release treatment layer with a silicone release agent. Drying is performed at 100 ° C. for 2 minutes to form a pressure-sensitive adhesive layer (tackifying resin-containing pressure-sensitive adhesive layer) having a thickness of 60 μm, and this tackifying resin-containing pressure-sensitive adhesive layer is made of a nonwoven fabric substrate (trade name “SP base paper— 14 ”manufactured by Daifuku Paper Co., Ltd.) to prepare an adhesive sheet (double-sided adhesive sheet).

(Example 2)
As an emulsion containing a tackifying resin, a trade name “Tamanol E-200-NT” (manufactured by Arakawa Chemical Industries, Ltd .; softening point 150 ° C .; rosin phenolic resin), water-dispersed acrylic polymer: 100 parts ( A pressure-sensitive adhesive sheet (double-sided pressure-sensitive adhesive sheet) was produced in the same manner as in Example 1 except that 30 parts in terms of solid content was used relative to (solid content). The trade name “Tamanol E-200-NT” is a tackifying resin-containing emulsion produced using an alicyclic hydrocarbon-based organic solvent.

(Example 3)
Using a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, butyl acrylate: 90 parts, 2-ethylhexyl acrylate: 10 parts, acrylic acid: 4 parts, dodecanethiol (chain transfer agent): 0 .05 parts, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride (polymerization initiator): 0.1 part, 3-methacryloyloxypropyltriethoxysilane ( Trade name “KBM-503” manufactured by Shin-Etsu Silicone Co., Ltd.): 0.06 part is added to 100 parts of water to which 2 parts of polyoxyethylene lauryl sodium sulfate (emulsifier) is added, and the reaction vessel is charged and stirred. However, the temperature was raised to 60 ° C., an emulsion polymerization reaction was carried out at 60 ° C. for 4 hours, and then aged for 2 hours to obtain a reaction mixture containing an acrylic polymer.

  To the reaction mixture, 10% ammonia water was added to adjust the pH to 7 to obtain an aqueous dispersion of an acrylic polymer (water-dispersed acrylic polymer).

  For the water-dispersed acrylic polymer, 100 parts (solid content) of the water-dispersed acrylic polymer, an emulsion containing a tackifying resin, trade name “SK-253NS” (manufactured by Harima Chemical Co., Ltd.) Softening point 145 ° C .; polymerized rosin resin) was added in an amount of 30 parts in terms of solid content to obtain a water-dispersed pressure-sensitive adhesive (water-dispersed acrylic pressure-sensitive adhesive) containing a tackifier resin.

  This water-dispersed acrylic pressure-sensitive adhesive was applied to the surface of a release treatment layer of a release liner (trade name “SLB-80WD (V2)” manufactured by Kite Chemical Industries, Ltd.) having a release treatment layer with a silicone release agent. Drying is performed at 100 ° C. for 2 minutes to form a pressure-sensitive adhesive layer (tackifying resin-containing pressure-sensitive adhesive layer) having a thickness of 60 μm, and this tackifying resin-containing pressure-sensitive adhesive layer is made of a nonwoven fabric substrate (trade name “SP base paper— 14 ”manufactured by Daifuku Paper Co., Ltd.) to prepare an adhesive sheet (double-sided adhesive sheet).

Example 4
In the same manner as in Example 1, a water-dispersed acrylic pressure-sensitive adhesive was prepared. This water-dispersed acrylic pressure-sensitive adhesive was applied to the surface of a release treatment layer of a release liner (trade name “SLB-80WD (V2)” manufactured by Kite Chemical Industries, Ltd.) having a release treatment layer with a silicone release agent. It dried at 100 degreeC for 2 minute (s), the 60-micrometer-thick adhesive layer (tackifying resin containing adhesive layer) was formed, and the adhesive sheet (double-sided adhesive sheet) was produced.

(Comparative Example 1)
A water-dispersed acrylic polymer was prepared in the same manner as in Example 1. This water-dispersed acrylic polymer was applied to the surface of the release treatment layer of a release liner (trade name “SLB-80WD (V2)” manufactured by Kite Chemical Industries, Ltd.) having a release treatment layer with a silicone release agent. Drying is carried out at 100 ° C. for 2 minutes to form a 60 μm-thick pressure-sensitive adhesive layer (tackifying resin-free pressure-sensitive adhesive layer). A pressure-sensitive adhesive sheet (double-sided pressure-sensitive adhesive sheet) was prepared by bonding to both surfaces of a base paper-14 (made by Daifuku Paper Co., Ltd.). Therefore, the tackifier resin-containing emulsion is not contained in the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet.

(Comparative Example 2)
As an emulsion containing a tackifying resin, trade name “Tamanol E-200” (manufactured by Arakawa Chemical Industries, Ltd .; softening point 150 ° C .; rosin phenolic resin), 100 parts by weight of water-dispersed acrylic polymer (solid content) A pressure-sensitive adhesive sheet (double-sided pressure-sensitive adhesive sheet) was prepared in the same manner as in Example 1 except that 30 parts in terms of solid content were used. The trade name “Tamanol E-200” is a tackifying resin-containing emulsion produced using an aromatic hydrocarbon-based organic solvent.

(Evaluation)
About each adhesive sheet obtained by the Example and the comparative example, the emission amount of formaldehyde, the emission amount of toluene, adhesive force, and terminal peeling prevention property were measured or evaluated by the following method. The results are shown in Table 1.

(Method for measuring formaldehyde emission)
It measured by the method based on JISA1901 (2003). The surface area of the sample to be measured was 0.043 m ^2, and the formaldehyde content (μg / m ³ ) per unit volume of the pressure-sensitive adhesive sheet was calculated and quantified.

(Measurement method of toluene emission)
A predetermined size (area: 5 cm ² ) was cut from each adhesive sheet to prepare a sample, and the sample was put in a vial and sealed. Then, the bottle containing the sample is heated at 150 ° C. for 30 minutes by a headspace autosampler, 1.0 ml of heated gas is injected into the gas chromatograph measuring device, the amount of toluene is measured, The toluene content (μg / g) per unit weight was calculated and quantified.

(Measurement method of adhesive strength)
Each pressure-sensitive adhesive sheet was pressure-bonded to a stainless steel (SUS) plate by reciprocating a 2 kg roller once, left at 23 ° C. for 20 minutes, and then pulled using a tensile tester at a tensile speed of 300 mm / min. The peel adhesive strength (23 ° C., 50% RH; N / 20 mm) was measured.

(Evaluation method of device peeling prevention)
After sticking each pressure-sensitive adhesive sheet to an aluminum plate (area: 10 mm × 100 mm) having a thickness of 0.5 mm, the release liner is peeled off to expose the other pressure-sensitive adhesive surface, and the exposed pressure-sensitive adhesive surface has a diameter of 50 mm. It was bonded to the side of a cylindrical acrylic round bar. This was left for 2 hours in an atmosphere at 70 ° C. with the round bar upright, and the distance (height) (mm) at which the end of the aluminum plate was peeled was measured.

  From Table 1, the pressure-sensitive adhesive sheets according to Examples 1 to 4 are designed with a very low amount of formaldehyde and toluene released while maintaining good terminal peeling resistance and adhesive strength. It was confirmed that it was obtained.

11-16 each, pressure sensitive adhesive sheet 2 base material 3 tackifying resin-containing pressure sensitive adhesive layer 4 release liner

Claims (3)

Following formula (1)

(In Formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 2 to 14 carbon atoms)
A water-dispersed acrylic polymer in which a (meth) acrylic acid alkyl ester represented by the formula is used as a main monomer component and a functional group-containing monomer component is used as a copolymerizable monomer component , a crosslinking agent, and a tackifier resin A pressure-sensitive adhesive sheet having at least a pressure-sensitive adhesive layer made of a water-dispersible acrylic pressure-sensitive adhesive containing an emulsion containing
It is a double-sided pressure-sensitive adhesive sheet with a base material having an adhesive layer on both sides of the base material, and the base material is a nonwoven fabric,
The functional group-containing monomer is composed of a carboxyl group-containing monomer or an acid anhydride thereof, a hydroxyl group-containing monomer, an amide monomer, an amino group-containing monomer, an epoxy group-containing monomer, a cyano group-containing monomer, and a monomer having a nitrogen atom-containing ring. At least one monomer selected from
The crosslinking agent is an isocyanate crosslinking agent, epoxy crosslinking agent, oxazoline crosslinking agent, aziridine crosslinking agent, melamine crosslinking agent, peroxide crosslinking agent, urea crosslinking agent, metal alkoxide crosslinking agent, metal chelate. A crosslinking agent selected from the group consisting of a system crosslinking agent, a metal salt crosslinking agent, a carbodiimide crosslinking agent, and an amine crosslinking agent,
The amount of the crosslinking agent used is 0.01 to 5 parts by weight with respect to 100 parts by weight of the acrylic polymer in the water-dispersed acrylic polymer,
The amount of the tackifying resin used is 10 to 100 parts by weight with respect to 100 parts by weight of the acrylic polymer in the water-dispersed acrylic polymer,
The tackifying resin has a softening point of 120 ° C. or more and 155 ° C. or less, a formaldehyde emission amount of less than 3 μg / m ³ , and a toluene emission amount of 10 μg / g or less. A pressure-sensitive adhesive sheet used for fixing a material. The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 2 to 150 µm. The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the pressure-sensitive adhesive strength to a stainless steel (SUS) plate is 11 N / 20 mm or more.

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