JP2001172581A - Pressure sensitive adhesive sheet or pressure sensitive adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensitive adhesive sheet or tape which can be easily redisintegrated without being peeled in advance and without suffering adverse influence by a pressure sensitive adhesive in obtaining a regenerated pulp and can be regenerated as a pulp by an ordinary pulp regeneration process without contaminating adjusting water used in disintegration. SOLUTION: In the pressure sensitive adhesive sheet comprising a surface substrate, a pressure sensitive adhesive layer formed thereon and a release sheet releasably laminated on the pressure sensitive adhesive layer or in the pressure sensitive adhesive tape comprising a substrate, a releasing agent layer formed on the surface of the substrate and a pressure sensitive adhesive layer formed on the back surface of the substrate, the pressure sensitive adhesive layer has a swell ratio in water of at least 1.5 times and gives an average particle size of the re-dispersed pressure sensitive adhesive layer of 65 μm or less when disintegrated for 30 min by a TAPPI standard disintegrating machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive sheet or an adhesive tape. More specifically, the pressure-sensitive adhesive sheet and pressure-sensitive adhesive tape are excellent in re-disintegration with water,
The present invention relates to a pressure-sensitive adhesive sheet and a pressure-sensitive adhesive tape which can be easily re-disintegrated without adversely affecting a pressure-sensitive adhesive and a substrate when pulp is regenerated.

[0002]

2. Description of the Related Art Adhesive sheets and adhesive tapes are commercially available.
It is widely used for office work, stamps and other stamps, delivery slips, process control, home use, etc. The general configuration of the pressure-sensitive adhesive sheet is such that a pressure-sensitive adhesive is sandwiched between a surface substrate and a release sheet. On the other hand, the general configuration of the pressure-sensitive adhesive tape is such that a release agent layer, a substrate, and a pressure-sensitive adhesive layer are laminated in this order, and a release agent layer is provided on the surface of the substrate, and a pressure-sensitive adhesive layer is provided on the opposite surface. .

[0003] Paper, film, metal foil or the like is used as a base material. Generally, a release agent such as a silicone compound or a fluorine compound is applied to the release sheet of the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape substrate. The base material for the release sheet may be a high-density base paper such as glassine paper, a clay-coated paper, a kraft paper, a laminated paper obtained by laminating a resin film such as polyethylene on a high-quality paper, or a kraft paper or a high-quality paper. Resin-coated paper provided with a coating layer containing a water-soluble polymer such as polyvinyl alcohol or starch and a pigment as main components can be used. Above all, laminated paper obtained by laminating polyethylene is generally widely used.

As the pressure-sensitive adhesive, various types of pressure-sensitive adhesives such as rubber-based, acrylic-based, and vinyl ether-based emulsions, and solvent or solventless types are used. Such pressure-sensitive adhesive sheets and pressure-sensitive adhesive tapes are of a permanent adhesive type which are attached to products or the like, are used for packaging products or cardboard boxes, and are permanently used after being attached to the adherend. . In the case of a pressure-sensitive adhesive sheet, there is a re-peelable type in which the sheet is peeled and discarded after the purpose of display is achieved from the relation of a product or the like.

[0005] As a method of using the adhesive sheet or the adhesive tape, for example, the adhesive sheet is composed of slips which are bound as an appendix in a magazine or the like, or are printed with forms such as an address display slip, a deposit slip, and a copy slip. It is attached to a cardboard as a delivery slip for home delivery, or attached to a returnable box such as a plastic container as a distribution management label. Recently, it is also used for stamps and other stamps. Further, the adhesive tape is mainly used for packing cardboard or the like, but in the papermaking industry, it is used for temporary fixing of winding after paper making and packaging at the time of shipping.

These pressure-sensitive adhesive sheets or pressure-sensitive adhesive tapes are used for a wide variety of applications because of their simplicity. However, due to the recent growing interest in environmental issues and resource saving, etc. It is necessary to take into account the characteristics. For example, a label used for a returnable box such as a plastic container has to be easily peeled off in a washing process in order to reuse the container after achieving the purpose of distribution management. Adhesive sheets or wrapping paper with adhesive labels attached to magazines as an appendix to increase consumers' motivation to purchase may be mixed with used paper in the recycling process. The necessity of a pressure-sensitive adhesive sheet or a pressure-sensitive adhesive label which does not cause any problem is mentioned.

[0007] Regarding the recycling of waste paper, in Japan, the amount of waste paper, including recycled waste paper, as a raw material for pulp production currently exceeds 50% of the raw material for paper and paperboard production, and the position of the main raw material is already in place. In the past, recycled paper has been reused for the same type or lower grade paper, like reusing newspaper for newsprint or lower grade recycled paper, and corrugated cardboard for cardboard. It was assumed that. Due to the recent growing interest in environmental issues,
The amount of used paper is expected to increase further in the future, but if you try to use more used paper, it is possible that more widely used adhesive sheets, labels and tapes will be mixed into the used paper. It is big.

In general, a defibration step of defibrating waste paper to obtain a pulp suspension, a rough selection for separating foreign matter in the pulp suspension,
Recycling pulping is performed through a selective process, a deinking process of separating printing ink, and a bleaching process of whitening the color. However, waxed paper, adhesive sheets, adhesive labels, adhesive tapes, etc., are insoluble in water from pulp fibers,
It is considered to be a waste paper that cannot separate adhesives and the like and is difficult to recycle pulping. Especially in the case of pressure-sensitive adhesive sheets, pressure-sensitive adhesive labels and pressure-sensitive adhesive tapes, 5 to 50% of water-insoluble pressure-sensitive adhesive is contained, and since this pressure-sensitive adhesive has strong adhesive force, separation from pulp fiber is impossible. It has been. Also, when used as an adhesive sheet for stamps, a stamp release layer is provided on the back surface of the stamp paper so that stamp collectors and the like can easily detach stamps from a substrate such as an envelope so that they can be peeled off in water. However, since the pressure-sensitive adhesive remains on the base material, it is difficult to recycle the base material.

When paper is made using recycled pulp containing a pressure-sensitive adhesive component, the pressure-sensitive adhesive closes the eyes of the wire and stains press rolls and blankets in the paper-making process, causing paper breakage and markedly increasing paper-making efficiency. There is a problem that the formation of the paper layer or the quality is adversely affected, such as a problem of lowering or formation of spots on the paper layer.

Further, since the release sheet used for the pressure-sensitive adhesive sheet is a release sheet having poor disintegration properties, such as the use of laminated paper obtained by laminating polyethylene, it is more difficult to make recycled pulps. Due to these problems, at present, recycled pulping of waste paper, adhesive labels, packaging base materials with adhesive tape, and corrugated cardboard has been avoided, and it is actually an industrial waste. is there.

Recently, due to problems of forest resources, environmental protection, etc., there have been reported several cases in which adhesive products which cannot be recycled as described above have been successfully recycled by devising them physically or by equipment. However, any of the general waste paper processing methods is a special processing method for removing adhesive foreign matter.

Further, a type using an adhesive which dissolves in water or alkaline water has also been proposed. In this case, since the adhesive is dissolved, a white water is used in a disintegrating and papermaking system. It was difficult to completely remove the adhesive component. Furthermore, since these pressure-sensitive adhesives are designed to have a low molecular weight, there is a disadvantage that the quality is significantly deteriorated in a high-temperature and high-humidity environment.

[0013]

DISCLOSURE OF THE INVENTION The present invention relates to an adhesive sheet and a pressure-sensitive adhesive tape which lose their tackiness in water, thereby reducing the pressure-sensitive adhesive sheet and the adhesive tape, the packaging base material to which the adhesive tape is attached, and the corrugated paper. In order to obtain recycled pulp without peeling off the adhesive label and adhesive tape in advance, the adhesive can be easily defibrated without adversely affecting the pulp during the normal recycled pulping process without contaminating the conditioning water at the time of defibration. It is an object of the present invention to provide a recyclable pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape which can be recycled and is stable in quality. Furthermore, by utilizing the properties of such adhesives, even if they are affixed as labels or sealing tapes to returnable boxes or glass bottles in distribution departments such as plastic containers, the labels or tapes can be easily washed with water. It is also possible to apply to a pressure-sensitive adhesive sheet, a pressure-sensitive adhesive tape or the like which can be peeled off and the container can be reused.

[0014]

According to the present invention, there is provided (1) a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive layer formed on a surface substrate, and a release sheet laminated on the pressure-sensitive adhesive layer so as to be peelable. ,
In the pressure-sensitive adhesive tape provided with a pressure-sensitive adhesive layer on the back surface, the swelling ratio of the pressure-sensitive adhesive layer to water is 1.5 times or more, and TAP
The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape, wherein the pressure-sensitive adhesive layer which has been deflocculated by a PI standard deflocator for 30 minutes and redispersed has a particle size of 65 μm or less.

Further, the present invention provides (2) the pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to (1), wherein the glass transition temperature of the pressure-sensitive adhesive is -70 to -40 ° C. (3) The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to (1) or (2), wherein the pressure-sensitive adhesive copolymer composition contains 10 to 30% by mass of a copolymerizable hydrophilic component. (4) at the time of copolymerizing the pressure-sensitive adhesive, at least one of (poly) alkylene glycol di (meth) acrylate, (poly) alkylene glycol mono (meth) acrylate, (poly) ethylene glycol, and (poly) propylene glycol The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to any one of (1) to (3), wherein the pressure-sensitive adhesive is a pressure-sensitive adhesive obtained by copolymerization in the presence of: (5) The (poly) alkylene glycol di (meth) acrylate or (poly) alkylene glycol mono (meth) acrylate used during copolymerization of the pressure-sensitive adhesive has an addition mole number of alkylene glycol of 1 to 23. An adhesive sheet or an adhesive tape according to any one of (1) to (4). (6) The (poly) alkylene glycol di (meth) acrylate used during the copolymerization of the pressure-sensitive adhesive is polyethylene glycol dimethacrylate, and the amount added is 0.1 to 5% by mass based on the total monomer mixture. The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape according to any one of (1) to (5), wherein (7) The amount of (poly) ethylene glycol and / or (poly) propylene glycol used during copolymerization of the pressure-sensitive adhesive is 0.1 to 15 relative to the total monomer mixture.
The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape according to any one of (1) to (6), which is a mass%. (8) The amount of the (poly) alkylene glycol mono (meth) acrylate added is 0.1 to the total monomer mixture.
The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape according to any one of (1) to (7), wherein

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, according to the present invention, the pressure-sensitive adhesive layer loses its adhesiveness in water, so that the label or tape applied thereto can be easily removed by washing with water. It is intended to provide a pressure-sensitive adhesive sheet and a pressure-sensitive adhesive tape which are extremely excellent in suitability for recycled pulping by comprising a pressure-sensitive adhesive having particularly excellent redispersibility in water. In order to obtain such an adhesive sheet and an adhesive tape, the swelling ratio of the adhesive layer to water is 1.5 times or more, and TA
It is characterized in that a pressure-sensitive adhesive is used which is disintegrated with a PPI standard disintegrator for 30 minutes and the particle size of the re-dispersed pressure-sensitive adhesive layer becomes 65 μm or less.

The pressure-sensitive adhesive used in the pressure-sensitive adhesive sheet and the pressure-sensitive adhesive tape of the present invention has a water swelling ratio of the pressure-sensitive adhesive layer of 1.5 times or more, and is defibrated by a TAPPI standard deflocator for 30 minutes and redispersed. An adhesive in which the particle size of the adhesive layer is 65 μm or less.

The swelling ratio of the pressure-sensitive adhesive referred to here is a value obtained as follows. In the case of an adhesive sheet, the surface substrate / adhesive from which the release paper was removed was used. In the case of an adhesive tape, the tape itself was used as a sample.
The thickness of the pressure-sensitive adhesive film after immersion for 0 minutes was measured, and the swelling ratio was determined according to the following formula. At this time, before measuring the thickness of the pressure-sensitive adhesive film, a commercially available polyethylene terephthalate film (PET) having a thickness of 50 μm was superimposed on the pressure-sensitive adhesive layer, and the measurement was performed. The thickness of the substrate is measured in the same manner as above, with the pressure-sensitive adhesive layer being swollen and removed using an organic solvent such as toluene. (Unit: times)

[0019]

(Equation 1)

The TAPPI standard disintegrator referred to here is an apparatus described in Appendix A of JIS-P-8220. A removable container has 1200 ml of water and air-dried paper / adhesive equivalent to 50 g. Adhesive sheet or adhesive tape composed of the adhesive / release paper and affixed to a high quality paper of 70 g / m ² of commercial rice tsubo is put as a sample, disintegrated for 30 minutes, and the suspension of the adhesive sheet or adhesive tape is removed. Fabrication,
This suspension was filtered through a 60-mesh nylon screen, and the filtrate was passed through a particle size distribution meter to measure the average particle size of the re-dispersed pressure-sensitive adhesive particles. (Unit: μm)

Then, the inventors have determined that the above
The swelling ratio of the pressure-sensitive adhesive layer after 10 minutes with water at 0 ° C. is 1.5 times or more, more preferably 2 times or more, and the particle size of the pressure-sensitive adhesive layer redispersed after defibration for 30 minutes with a TAPPI standard disintegrator is 65%.
It has been found that a pressure-sensitive adhesive having a thickness of at most 50 μm, more preferably at most 50 μm, has particularly excellent redispersibility in water of a pressure-sensitive adhesive layer, and can provide a pressure-sensitive adhesive sheet and a pressure-sensitive adhesive tape which are extremely excellent at the time of recycled pulping. Incidentally, when the swelling ratio of the pressure-sensitive adhesive layer is smaller than 1.5 times, the pressure-sensitive adhesive layer is
When disintegrated with an I-standard disintegrator for 30 minutes, the particle size of the redispersed pressure-sensitive adhesive layer becomes larger than 65 µm, and pressure-sensitive adhesive particles remain in the pulp during the formation of a pulp sheet in papermaking, which has an adverse effect.

Further, in order to obtain the pressure-sensitive adhesive, it is essential to incorporate a hydrophilic monomer into the pressure-sensitive adhesive composition. However, if a large amount of such a monomer is used, the glass transition temperature of the pressure-sensitive adhesive copolymer is reduced. And high tackiness is not exhibited. Therefore, in determining the adhesive composition in consideration of the balance between the adhesiveness and hydrophilicity of the adhesive, and the water redispersibility, the glass transition temperature of the adhesive is in the range of −70 to −40 ° C., and more preferably −70 ° C. It is preferable to produce a pressure-sensitive adhesive by blending various monomers so as to be in the range of -45 ° C. The glass transition temperature of the pressure-sensitive adhesive here means the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is swollen with an organic solvent such as toluene or methyl ethyl ketone, scraped off from the substrate, the organic solvent is volatilized, and then the differential scanning calorimetry is performed. It is a value measured by a total. (Unit: ° C)

Incidentally, the glass transition temperature of the adhesive is -70 ° C.
If the amount is less than the above, the water redispersibility of the obtained film is impaired. On the other hand, if the temperature exceeds -40 ° C, the obtained film becomes hard and has poor practicality.

In order to obtain the pressure-sensitive adhesive, the pressure-sensitive adhesive composition preferably contains a copolymerizable hydrophilic component in an amount of 10 to 30% by mass.

Examples of the copolymerizable hydrophilic component include acrylic acid, methacrylic acid, crotonic acid,
Monomers containing ethylenically unsaturated carboxylic acids such as maleic acid, fumaric acid, monoalkyl maleic acid, monoalkyl itaconic acid, monoalkyl fumaric acid, alkoxyalkyl (meth) acrylates such as methoxyethyl acrylate, ethoxyethyl acrylate, and carboxylic acid modified Rosin ester, caprolactone adduct of (meth) acrylic acid, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate And the like.

These compounds can be suitably used in consideration of the balance between hydrophilicity, water redispersibility and adhesive performance of the adhesive. And these monomers are copolymers of 10 to 30.
It is desirable to copolymerize so as to account for the mass%. If it is less than 10% by mass, the hydrophilicity of the pressure-sensitive adhesive will be reduced. On the other hand, if it exceeds 30% by mass, the adhesive performance will be reduced.

In addition to the above-mentioned hydrophilic monomers, copolymerizable monomers include butyl (meth) acrylate, hexyl (meth) acrylate, and (meth) acrylic acid as components for imparting the tackiness of the pressure-sensitive adhesive. Octyl, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, and the like, as components for adjusting the adhesive performance,
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, cyclohexyl (meth) acrylate, glycidyl (meth) acrylate, vinyl acetate, vinyl propionate, vinyl chloride, styrene,
Ethylene and the like. These compounds can be suitably used in consideration of the balance of the adhesive performance of the adhesive, but from the viewpoint of the adhesiveness and cohesion of the adhesive, butyl (meth) acrylate, (meth) acrylic acid-2- It is more preferable to use ethylhexyl, methyl (meth) acrylate, and vinyl acetate.

Further, (Poly) alkylene glycol di (meth) acrylate, (Poly) alkylene glycol mono (meth) acrylate, (Poly) ethylene glycol, (Poly) propylene glycol during the production of the copolymer for obtaining the pressure-sensitive adhesive. May be added.

(Poly) alkylene glycol di (meth)
The acrylate is a compound represented by the following general formula (1), for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate,
Examples include tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and polypropylene glycol di (meth) acrylate.

[0030]

Embedded image [In the formula, R represents a methyl group or a hydrogen atom, and n represents an integer of 1 to 23. ]

(Poly) alkylene glycol di (meth)
When a copolymer is produced in the presence of an acrylate, hydrophilicity can be imparted to the pressure-sensitive adhesive and the molecular weight can be increased, so that the particles after redispersion become hard, and the particles remaining in the recycling process become sticky in water. Is more preferred because it does not express

These compounds can be suitably used in consideration of the balance between hydrophilicity, water redispersibility and adhesive performance of the pressure-sensitive adhesive. Among them, polyethylene glycol dimethacrylate is particularly suitable for hydrophilicity and water redispersibility. It is more preferable since a copolymer excellent in the above is obtained.

Incidentally, the (poly) alkylene glycol di (meth) acrylate is based on the total monomer mixture.
It is desirable to add in the range of 0.1 to 5% by mass. If the amount is less than 0.1% by mass, the water redispersibility of the pressure-sensitive adhesive becomes insufficient. On the other hand, if it exceeds 5% by mass, the pressure-sensitive adhesive is likely to aggregate during polymerization.

The (poly) alkylene glycol mono (meth) acrylate is a compound represented by the following general formula (2), for example, ethylene glycol mono (meth) acrylate, diethylene glycol mono (meth) acrylate, triethylene glycol mono ( (Meth) acrylate, tetraethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, and the like.

[0035]

Embedded image [In the formula, R represents a methyl group or a hydrogen atom, and n represents an integer of 1 to 23. ]

When the above copolymer is produced in the presence of the (poly) alkylene glycol mono (meth) acrylate, the pressure-sensitive adhesive can be imparted with hydrophilicity and, at the same time, the pressure-sensitive adhesive can be plasticized. This makes it possible to produce an adhesive suitable for recycling that has a good balance between properties and adhesive performance.

The (poly) alkylene glycol mono (meth) acrylate must be added in the range of 0.1 to 5% by mass based on the total monomer mixture. By the way, if it is less than 0.1% by mass, the water redispersibility of the pressure-sensitive adhesive becomes insufficient. On the other hand, if it exceeds 5% by mass, the cohesive strength of the pressure-sensitive adhesive will decrease.

The (poly) ethylene glycol and / or (poly) propylene glycol is a compound represented by the following general formula (3).

[0039]

Embedded image Wherein R is a methyl group or a hydrogen atom, and n is 1 to 500.
Represents an integer. ]

When the above copolymer is produced in the presence of (poly) ethylene glycol and / or (poly) propylene glycol, a hydrophilicity can be imparted to the pressure-sensitive adhesive, so that the copolymer is excellent in hydrophilicity and film swellability. Is obtained, and an adhesive suitable for recycling with good water redispersibility can be produced.

The (poly) ethylene glycol and / or (poly) propylene glycol must be added in the range of 0.1 to 15% by mass, more preferably 0.3 to 10% by mass, based on the total monomer mixture. There is. By the way, if it is less than 0.1% by mass, the water redispersibility of the pressure-sensitive adhesive becomes insufficient. On the other hand, if it exceeds 15% by mass, the viscosity tends to increase, and the handleability of the pressure-sensitive adhesive decreases. If the number of moles of the alkylene glycol added to the (poly) alkylene glycol di (meth) acrylate or the (poly) alkylene glycol mono (meth) acrylate exceeds 23, the particles after redispersion are not so hard, and in the recycling step. The remaining particles develop tackiness in water, which may adversely affect paper layer formation or quality during paper recycling.

Further, a hydrophilic plasticizing substance may be added to the pressure-sensitive adhesive in order to adjust physical properties of the pressure-sensitive adhesive and to prevent discoloration and deterioration of the pressure-sensitive adhesive over time. Examples of the hydrophilic plasticizing substance include monoethanolamine, diethanolamine, triethanolamine, propanolamine, β-propanolamine, tripropanolamine, isopropanolamine, triisopropanolamine, 2-aminoisohexyl alcohol, and N-methyl. Alkanolamines having a boiling point of 100 ° C. or higher, such as diethanolamine, N, N-dibutylethanolamine, sugar alcohols such as glycerin, sorbit, mannitol, dursit, idit, erythritol, arabit, adnit, polyethylene oxide or polypropylene oxide and glycerin; Copolymers with polyhydric alcohols such as xylitol trioxyisobutane and sorbit, and polyethylene glycol and polypropylene glycol And Li polyether polyol, a copolymer of ethylene oxide and propylene oxide, polyoxyethylene alkyl er tail, polyoxyethylene alkyl phenyl ether, nonionic surfactants such as polyoxyethylene polyoxypropylene glycol, and the like. These substances should be used in an amount of not more than 20% by mass, more preferably in the range of 0.5 to 20% by mass, based on the solid content of the copolymer, in consideration of tackiness and water redispersibility. Is desirable.

Among these hydrophilic plasticizing substances, alkanolamines having a boiling point of 100 ° C. or higher and nonionic surfactants can finish a pressure-sensitive adhesive having good adhesiveness and storage stability. preferable.

The method for producing the above copolymer is not particularly limited. For example, water, a solvent,
It is manufactured by a known method such as a method of solution polymerization in the presence of a chain transfer agent and a polymerization initiator, and a method of emulsion polymerization in an aqueous system in the presence of an emulsifier, a chain transfer agent, a polymerization initiator and a dispersant. .

Examples of the polymerization initiator used in the polymerization include persulfates such as potassium persulfate and ammonium persulfate, 2,2′-azobisisobutyronitrile,
From azo compounds such as 2′-azobis (2,4-dimethylvaleronitrile), peroxides such as hydrogen peroxide, benzoyl peroxide, lauryl peroxide, and combinations of ammonium persulfate with sodium sulfite, acidic sodium sulfite, etc. , A so-called redox-based polymerization initiator. The amount of the polymerization initiator to be used is generally 0.2 to 2% by mass, more preferably about 0.3 to 1% by mass, based on the total amount of monomers commonly used for polymerization.

Examples of the chain transfer agent to be added at the time of the copolymerization include alkyl mercaptans such as octyl mercaptan, nonyl mercaptan, decyl mercaptan, dodecyl mercaptan, N-dodecyl mercaptan, octyl thioglycolate, nonyl thioglycolate, and thioglycolic acid. Thioglycolic acid esters such as 2-ethylhexyl and 2-ethylhexyl β-mercaptopropionate; 2,4-diphenyl-4-methyl-1-pentene; 1-methyl-4-isopropylidene-1-cyclohexene; I can do it. In particular, thioglycolic acid esters, 2,4-diphenyl-4-methyl-1-
When pentene or 1-methyl-4-isopropylidene-1-cyclohexene is used, the obtained copolymer has a low odor, which is preferable. The amount of the chain transfer agent used is
The amount is adjusted to about 0.001 to 3% by mass of all monomers to be polymerized. Further, organic solvents such as methanol, ethanol, and isopropyl alcohol can also be used.

The monomer concentration during the polymerization is usually from 30 to 70.
%, Preferably about 40 to 60% by mass. Further, the polymerization reaction is usually performed at a temperature of 60 to 100 ° C. for 2 to 8 hours. Further, a wetting agent, a leveling agent, a thickener, an antifoaming agent, a preservative and the like can be appropriately added. Also, if desired, the performance of the adhesive,
In particular, for the purpose of improving physical properties such as adhesion and cohesion to a polyolefin-based adherend, an ethylene-vinyl acetate copolymer,
An ethylene-vinyl acetate-acrylic copolymer can also be added.

The copolymer obtained by the above-mentioned method is prepared by using a hydroxide of an alkali metal such as potassium hydroxide or sodium hydroxide corresponding to 50 to 120 mol% of the carboxyl group in the copolymer, ammonia or the like. By performing the neutralization treatment, the mechanical stability can be improved and the viscosity can be adjusted. It is more preferable to use an alkali metal hydroxide from the viewpoint of preventing the adhesive performance from deteriorating due to evaporation over time after being processed into an adhesive sheet and an adhesive tape.

Next, as a surface substrate used for the pressure-sensitive adhesive sheet, for example, a film (cellophane, polyethylene, polypropylene, soft polyvinyl chloride, hard polyvinyl chloride,
Polyester, etc.), paper (high quality paper, art paper, coated paper,
Supports such as cast paper, foil paper, kraft paper, polyethylene laminated paper, impregnated paper, vapor-deposited paper, low-size paper, water-soluble paper, etc., metal foils, synthetic paper, etc., as well as heat-sensitive recording layers and thermal transfer recording A layer provided with an image receiving layer, an image receiving layer for ink jet recording, various printing layers, a coloring layer, a concealing layer, and the like can be appropriately selected and used.

Considering the recyclability of the adhesive sheet, paper such as high-quality paper, art paper, coated paper, cast paper, kraft paper, impregnated paper, low-size paper, water-soluble paper, kraft paper or high-quality paper, etc. Casein, dextrin,
Starch, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose,
Natural or synthetic resins and / or pigments such as polyvinyl alcohol, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, and acrylate copolymer Paper such as a base material provided with a filler layer having a main component such as polyvinyl alcohol, carboxymethylcellulose, a water-soluble film formed from a water-soluble polymer such as methylcellulose, or lactic acid or lactide and glycolic acid, hydroxy. Butyric acid, hydroxyvaleric acid, hydroxypentanoic acid, hydroxycaproic acid,
It is desirable to use a film that is easily hydrolyzed with an aqueous alkali solution formed from a copolymer with a hydroxycarboxylic acid such as hydroxyheptanoic acid or a lactic acid-based polymer such as polylactic acid.

When used as an adhesive label for physical distribution management, for example, a release agent is applied to the heat-sensitive layer side of the heat-sensitive paper, or the releasability is applied to the printing surface of printing paper such as art paper or coated paper. It may be a tape-like material that does not use a release paper in which a layer to be printed is provided and an adhesive layer is laminated on the opposite surface.

Next, as a release sheet of the pressure-sensitive adhesive sheet or a base material of the pressure-sensitive adhesive tape, high-density base paper such as glassine paper, clay-coated paper, glassine paper, kraft paper or high-quality paper, for example, casein, dextrin , Starch, carboxymethylcellulose, methylcellulose,
Ethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, ethylene-
Vinyl chloride copolymer, ethylene-vinyl acetate copolymer,
A base material provided with a filler layer mainly composed of a natural or synthetic resin such as an acrylate copolymer and / or a pigment; laminated paper obtained by laminating polyethylene or the like on glassine paper, kraft paper or high-quality paper; paper),
Films such as polypropylene and polyester can be mentioned.

In particular, considering the recyclability of the pressure-sensitive adhesive sheet including the release sheet and the recyclability as a tape, among the above-mentioned base materials, for example, casein, dextrin and the like may be used for clay-coated paper, kraft paper or high-quality paper. , Starch, carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, acrylate A base material provided with a filler layer mainly composed of a natural or synthetic resin such as a copolymer and / or a pigment, and a water-soluble filler formed from a water-soluble polymer such as polyvinyl alcohol, carboxymethylcellulose, and methylcellulose. Or a copolymer of lactic acid or lactide and glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypentanoic acid, hydroxycaproic acid, hydroxyheptanoic acid or the like, or an alkali formed from a lactic acid-based polymer such as polylactic acid. It is desirable to use a film which is easily hydrolyzed with an aqueous solution.

When papers are used for the surface substrate of the pressure-sensitive adhesive sheet, the release sheet, and the pressure-sensitive adhesive tape, it is desirable to use paper having a paper layer pH of 6 or less. This is because, in the region where the pH of the paper layer is higher than 6, the hydrophilic component in the pressure-sensitive adhesive composition, particularly a compound having a carboxyl group, is easily affected by calcium carbonate and the like contained in the paper, and the pressure-sensitive adhesive deteriorates. It is. In addition, the paper layer pH here refers to the surface of the pressure-sensitive adhesive sheet, the surface opposite to the pressure-sensitive adhesive in the case of a release sheet, or the surface of the pressure-sensitive adhesive tape substrate in which the pressure-sensitive adhesive is swollen with an organic solvent and scraped off. Is peeled off with a cellophane tape or the like, and a commercially available test solution that changes color depending on pH is applied to the paper layer, and colorimetrically determined with a standard color.

The sealing layer mainly composed of a resin and / or a pigment used for the release sheet of the pressure-sensitive adhesive sheet or the base material of the pressure-sensitive adhesive tape is not particularly limited. For example, casein, dextrin, starch, carboxy, etc. Natural or synthetic resins such as methyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, ethylene-vinyl chloride copolymer, acrylate copolymer and / or Inorganic pigments such as kaolin, calcium carbonate, clay, talc, calcined kaolin, delamikaolin, titanium dioxide, aluminum hydroxide, silica, white carbon, polystyrene resin fine particles, urea-formalin resin fine particles It may be an organic synthetic pigments such as fine hollow particles.

In addition to the base material provided with the filler layer, a printing coating layer containing a pigment as a main component was provided on the surface of the paper, such as art paper, coated paper, or cast coated paper. A substrate may be used.

In the case where the above-mentioned printing pigment coating layer is provided, an adhesive is used in the pigment coating liquid, in addition to the pigment, for fixing the pigments together and the pigment and the surface of the substrate. Such adhesives include, for example, casein, dextrin,
Starch, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose,
Natural or synthetic adhesives such as polyvinyl alcohol, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, and acrylate ester copolymer , Aqueous solution or dispersion (emulsion)
Used in the form of In addition, in addition to these pigments and adhesives, a defoamer,
If necessary, various auxiliary agents such as dispersants, preservatives, dyes,
It can also be added.

The coating liquid for the filling layer containing such a resin and / or a pigment as a main component can be prepared by a conventional coating method such as a blade coater, bar or rod coater, air knife coater, gravure coater, roll coater, die coater, lip coater and the like. Is applied by a coating device of The coating amount in this case is 2 g / m ² or more, preferably 4 g / m ^{2 in} terms of solid content mass.
It is adjusted in the range of ３０30 g / m ² .

The release agent used for the release sheet of the pressure-sensitive adhesive sheet and the release agent layer formed on one surface of the pressure-sensitive adhesive tape substrate in the present invention is not particularly limited, and is generally used in the form of a water-dispersed type, a solvent type or a non-aqueous type. After coating a solvent-type silicone resin or fluorine resin at a dry mass of about 0.05 to 3 g / m ² , a release layer is formed by heat curing, ionizing radiation curing, or the like. Above all, solventless silicone does not use harmful solvents when forming a release layer,
Further, it is more preferably used because it has excellent drying efficiency as compared with the water dispersion type.

In the method of forming the pressure-sensitive adhesive sheet, usually, a pressure-sensitive adhesive is coated on the release agent surface of the release sheet, dried to form a pressure-sensitive adhesive layer, and then bonded to a surface substrate to finish.
The pressure-sensitive adhesive layer may be provided by directly coating the pressure-sensitive adhesive on the surface substrate.

The method of forming the pressure-sensitive adhesive tape is usually finished by directly coating the pressure-sensitive adhesive on the back surface of the base material provided with the release agent layer or the release-printable layer, drying and providing the pressure-sensitive adhesive layer. Once the adhesive was coated on the release agent layer side of the release paper for the process and dried, the back surface of the tape substrate provided with a release agent layer and a release printable layer on the surface was bonded to finish the adhesive sheet. The adhesive tape may be finished later while removing the release sheet.

When forming the pressure-sensitive adhesive sheet and the pressure-sensitive adhesive tape, the pressure-sensitive adhesive is adjusted to a viscosity of usually about 0.01 to 9 Pascal second by means of adjusting the molecular weight, diluting with water, or increasing the viscosity to form a release sheet. Coated. As the coating apparatus in this case, for example, a reverse roll coater, a knife coater, an air knife coater, a bar or rod coater, a slot die coater, a lip coater, a reverse gravure coater or the like is used. In the pressure-sensitive adhesive sheet and the pressure-sensitive adhesive tape of the present invention, the coating device is not particularly limited, and is manufactured by these general methods. The coating amount of the pressure-sensitive adhesive is adjusted in a range of about 5 to 50 g / m ² . By the way, when it is less than 5 g / m ² , the adhesive performance of the obtained pressure-sensitive adhesive sheet and pressure-sensitive adhesive tape becomes insufficient, while 50
If it exceeds g / m ² , the pressure-sensitive adhesive may protrude during the production of the pressure-sensitive adhesive sheet and the pressure-sensitive adhesive tape, or may cause cohesive failure at the time of peeling.

[0063]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but of course, the present invention is not limited to these examples. All parts, ratios, coating amounts, and the like in the examples are solid contents or active ingredients on a mass basis unless otherwise specified.

Example 1 (Preparation of pressure-sensitive adhesive) First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 245 parts Acrylic acid: 45 parts Vinyl acetate: 15 parts Methoxyethyl acrylate: 75 parts Methyl methacrylate: 20 Anion emulsifier (trade name: Emal NC-35 / Kao Corporation): 6 parts Ion-exchanged water: 150 parts

Next, 150 parts of ion-exchanged water, 3 parts of potassium persulfate, and 1 part of octyl mercaptan were charged into a flask equipped with a stirrer, a cooler, a dropping funnel, a nitrogen suction pipe, and a thermometer. After heating to
The emulsified monomer mixture was dropped by 1/6. Reaction rate 9
When it reached 0%, the remaining monomer mixture was dropped over 3 hours to carry out polymerization. After completion of the dropwise addition, the mixture was aged at 80 ° C. for 3 hours to complete the reaction. Next, the contents of the flask are cooled to 40 ° C.
Then, a 10% aqueous solution of KOH was added to 50 mol% of the carboxyl groups in the copolymer to carry out a neutralization reaction, and 4 parts of triethanolamine was added to 100 parts of the adhesive, followed by vigorous stirring. An adhesive used in the present invention was produced.

(Preparation of base material for release paper provided with filler layer)
Kaolin (trade name: HT clay / Engel)
Hard Co.): 50 parts, acrylate copolymer
(Product name: Ricabond ET-84 / Chuo Rika Co., Ltd.): 5
0 parts, lubricant (trade name: Nopco C-104 / San Nopco)
0.5 parts, defoamer (trade name: NOPCO 1407K)
/ San Nopco): A composition consisting of 0.3 part
Mixed so that the concentration is 50%, and
64 g / m ^Two5 g / m dry weight on high quality paper^TwoWill be
It was coated and dried to provide a filler layer. Then, super
-Smooth finish with calender, base material for release paper
I got

Next, a solvent type silicone release agent (trade name: LTC-
300B / manufactured by Dow Corning Toray Co., Ltd .: 100 parts, catalyst (trade name: SRX-212 / manufactured by Dow Corning Toray Co., Ltd.): 0.8 part, coated so that the dry mass becomes 1.0 g / m ² , Heat cured.

[0068] (Preparation of pressure-sensitive adhesive sheet) described above, the release paper, the coating such that 25 g / m ² the resultant pressure-sensitive adhesive by dry weight, after drying, fine commercial basis weight 64 g / m ² The adhesive sheet was obtained by laminating with paper.

(Preparation of tape base material provided with filler layer)
Kaolin (trade name: KCS clay / EC)
C): 70 parts, phosphorylated ester starch (trade name: Neil Gum A-85 / Matsuya Chemical Co., Ltd.): 5 parts, SBR latex (trade name: L-1795 / Asahi Kasei Co., Ltd.): 25
Parts, dispersant (trade name: ARON A-9 / manufactured by Toagosei Chemical Industry Co., Ltd.):
%, And coated on a commercially available kraft paper of 73 g / m ^{2 with} a dry weight of 10 g / m ² and dried to form a filling layer.

Next, a solvent-type silicone release agent (trade name: SD-) was formed on the sealing layer of the tape base material thus obtained.
7220 / Toray Dow Corning): 100 parts, catalyst (trade name: SRX-212 / Toray Dow Corning): 0.6 parts, coated so that the dry weight becomes 1.0 g / m ² , Heat cured.

(Preparation of Adhesive Tape) The release agent layer was provided.
40 g of the above adhesive on a dry weight basis on the back surface of the tape base
/ M ^TwoAfter coating and drying so that
And the release agent layer surface of the tape base material
A light adhesive tape was made.

Example 2 (Preparation of adhesive) First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 285 parts Acrylic acid: 35 parts Vinyl acetate: 20 parts Methoxyethyl acrylate: 40 parts Methyl methacrylate: 20 Part Anionic emulsifier (trade name: Emal NC-35 / Kao Corporation): 6 parts Ion-exchanged water: 150 parts, and mixed with this emulsifier and ion-exchanged water (the same applies hereinafter). It was prepared by adding 0.9% by mass of dimethacrylate (trade name: NK ester 9G / manufactured by Shin-Nakamura Chemical Co., Ltd.). Next, a copolymer was produced in the same manner as in Example 1, and after the reaction was completed, 50 mol% of the carboxyl group in the copolymer was added with a 10% aqueous KOH solution to perform a neutralization reaction. Further, 4 parts of triethanolamine and 4 parts of nonionic surfactant (trade name: Emulgen 810 / Kao Corporation) are added to 100 parts of the adhesive, and the mixture is vigorously stirred and used in the present invention. An adhesive was produced.

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive was used.

An adhesive tape was produced in the same manner as in Example 1 except that the above-mentioned adhesive was used.

Example 3 First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 305 parts Acrylic acid: 35 parts Vinyl acetate: 20 parts Methoxyethyl acrylate: 20 parts Methyl methacrylate: 20 parts Anionic emulsifier (commercially available) Name: Emal NC-35 / Kao Corporation): 6 parts Ion-exchanged water: 150 parts were mixed, and polyethylene glycol dimethacrylate (trade name: NK Ester 9G / Shin Nakamura Chemical Co., Ltd.) was added to the total monomer mixture. 1.8 mass%, polypropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd./average molecular weight 100
0): It was prepared by adding 2.7% by mass. Next, a copolymer was produced in the same manner as in Example 1, and 10 minutes after the completion of the reaction.
The neutralization reaction was carried out by adding 50 mol% of the carboxyl groups in the copolymer with a% KOH aqueous solution. Furthermore, this adhesive 1
To 00 parts, 4 parts of triethanolamine and 4 parts of a nonionic surfactant (trade name: Emulgen 810 / Kao Corporation) were added, and the mixture was vigorously stirred to produce an adhesive used in the present invention. .

An adhesive sheet was prepared in the same manner as in Example 1 except that the above-mentioned adhesive was used.

An adhesive tape was produced in the same manner as in Example 1 except that the above-mentioned adhesive was used.

Example 4 (Production of adhesive) First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 225 parts Acrylic acid: 45 parts Vinyl acetate: 20 parts Methoxyethyl acrylate: 75 parts Hydroxyethyl methacrylate: 15 Methyl methacrylate: 20 parts Anionic emulsifier (trade name: Emar NC-35 / Kao Corporation): 6 parts Ion-exchanged water: 150 parts Then, triethanolamine: 4 was added to 100 parts of the copolymer in the same manner as in Example 1.
Was added and stirred vigorously to produce an adhesive used in the present invention.

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive was used.

An adhesive tape was produced in the same manner as in Example 1 except that the above-mentioned adhesive was used.

Example 5 (Synthesis of carboxylic acid-modified rosin ester) 70 g of methacrylic acid and 90 g of epichlorohydrin were placed in a flask equipped with a stirrer, an exhaust pipe, a dropping funnel, a nitrogen suction pipe, and a thermometer.
And heated to 100 ° C. under nitrogen gas and kept for 2 hours. Then, fully dissolved rosin abietic acid was added for 30 minutes.
0 g was added and kept at 230 ° C. for 2 hours. Next, 125 g of glutaric anhydride was added, and the mixture was kept at 230 ° C. for 2 hours to synthesize a carboxylic acid-modified rosin ester used in this experiment.

(Production of adhesive) First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 190 parts Acrylic acid: 30 parts Methoxyethyl acrylate: 90 parts Carboxylic acid-modified rosin ester: 90 parts Anionic emulsifier (commercially available) Name: Emar NC-35 / Kao Corporation): 6 parts Ion-exchanged water: 150 parts Then, into a flask equipped with a stirrer, cooler, dropping funnel, nitrogen suction pipe, thermometer,
Charge 150 parts of ion-exchanged water, 2 parts of potassium persulfate, and 2 parts of octyl mercaptan, and add 8 parts while purging with nitrogen.
After the temperature was raised to 0 ° C., 1/6 of the above monomer mixture was dropped. When the reaction rate reached 90%, the remaining emulsified monomer mixture was dropped over 3 hours to carry out polymerization. After completion of the dropwise addition, the mixture was aged at 80 ° C. for 3 hours to complete the reaction. Next, the contents of the flask are cooled to 40 ° C., and a 10% aqueous solution of KOH is added to 100 mol% of the carboxyl groups in the copolymer to carry out a neutralization reaction, followed by vigorous stirring to produce the pressure-sensitive adhesive used in the present invention. did.

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive was used.

An adhesive tape was produced in the same manner as in Example 1 except that the above-mentioned adhesive was used.

Example 6 (Production of adhesive) First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 250 parts Acrylic acid: 35 parts Vinyl acetate: 20 parts Methoxyethyl acrylate: 75 parts Methyl methacrylate: 20 Part Anionic emulsifier (trade name: Emal NC-35 / Kao Corporation): 6 parts Deionized water: 150 parts were mixed, and polyethylene glycol monomethacrylate (trade name: Blemmer PE-200) was added to all the monomer mixture. / Manufactured by NOF CORPORATION): 0.9% by mass was added. Next, a copolymer was produced in the same manner as in Example 1, and after the reaction was completed, 50 mol% of the carboxyl group in the copolymer was added with a 10% aqueous KOH solution to perform a neutralization reaction. Further, 4 parts of triethanolamine and 4 parts of nonionic surfactant (trade name: Emulgen 810 / Kao Corporation) are added to 100 parts of the adhesive, and the mixture is vigorously stirred and used in the present invention. An adhesive was produced.

An adhesive sheet was prepared in the same manner as in Example 1 except that the above-mentioned adhesive was used.

An adhesive tape was produced in the same manner as in Example 1 except that the above-mentioned adhesive was used.

Comparative Example 1 (Production of pressure-sensitive adhesive) As an emulsified monomer mixture, 2-ethylhexyl acrylate: 250 parts Acrylic acid: 35 parts Vinyl acetate: 20 parts Methoxyethyl acrylate: 75 parts Methyl methacrylate: 20 parts Anionic emulsifier (trade name: Emal NC-35 / Kao Corporation): 6 parts Ion-exchanged water: 150 parts were mixed, and acetoacetoxyethyl methacrylate: 0.9% by mass was added to the total monomer mixture. Prepared. Then, an adhesive was produced in the same manner as in Example 1. Further, 4 parts of triethanolamine was added to 100 parts of the adhesive, and vigorously stirred to produce an adhesive used in the present invention.

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive was used.

An adhesive tape was produced in the same manner as in Example 1 except that the above-mentioned adhesive was used.

Comparative Example 2 (Production of pressure-sensitive adhesive) As an emulsified monomer mixture, 2-ethylhexyl acrylate: 250 parts Acrylic acid: 65 parts Vinyl acetate: 20 parts Methoxyethyl acrylate: 55 parts Methyl methacrylate: 10 parts Anionic emulsifier (trade name: Emar NC-35 / Kao Corporation): 6 parts Ion-exchanged water: 150 parts was mixed and prepared. Then, into a flask equipped with a stirrer, cooler, dropping funnel, nitrogen suction pipe, thermometer,
Ion-exchanged water: 150 parts, potassium persulfate: 3 parts, octyl mercaptan: 2 parts, sodium carbonate: 3 parts were charged, and the temperature was raised to 80 ° C. while purging with nitrogen. . When the reaction rate reached 90%, the remaining emulsified monomer mixture was dropped over 3 hours to carry out polymerization. After completion of the dropwise addition, the mixture was aged at 80 ° C. for 3 hours to complete the reaction. Next, the contents of the flask were cooled to 40 ° C., and 100 parts of this copolymer was mixed with ethylene-vinyl acetate-acrylic copolymer (trade name: Sumikaflex S-3110).
/ Sumitomo Chemical Co., Ltd.): 27 parts were added, and the mixture was vigorously stirred to produce an adhesive used in the present invention.

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive was used.

A pressure-sensitive adhesive tape was prepared in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive was used.

Comparative Example 3 (Production of pressure-sensitive adhesive) 2-ethylhexyl acrylate: 290 parts Acrylic acid: 30 parts Vinyl acetate: 20 parts Methoxyethyl acrylate: 60 parts Anionic emulsifier (trade name) : Emal NC-35 / Kao Corporation): 6 parts ion-exchanged water: 150 parts Then, a copolymer was produced in the same manner as in Example 1. Based on 100 parts of the copolymer, triethanolamine: 8 parts, sugar alcohol (trade name: sorbitol / Niken Kagaku): 27 parts, Ethylene-vinegar
Acrylic copolymer (trade name: Sumikaflex S-311)
0 / manufactured by Sumitomo Chemical Co., Ltd.): 27 parts were added, and the mixture was vigorously stirred to produce an adhesive used in the present invention.

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive was used.

A pressure-sensitive adhesive tape was prepared in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive was used.

Comparative Example 4 (Production of adhesive) As an emulsified monomer mixture, 2-ethylhexyl acrylate: 350 parts Acrylic acid: 30 parts Vinyl acetate: 20 parts Anionic emulsifier (trade name: Emar NC-35 / Kao) 6 parts ion-exchanged water: 150 parts, and sodium tripolyphosphate: 0.9% by mass was added to the total monomer mixture.
Then, a copolymer was produced in the same manner as in Example 1, and 100 parts of this copolymer was added to triethanolamine: 4.
Parts, 15% aqueous solution of sodium tripolyphosphate: 20 parts,
27 parts of ethylene-vinyl acetate-acrylic copolymer (trade name: Sumikaflex S-3110 / Sumitomo Chemical Co., Ltd.) was added, and the mixture was vigorously stirred to produce and prepare an adhesive used in the present invention.

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive was used.

A pressure-sensitive adhesive tape was prepared in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive was used.

Comparative Example 5 (Production of adhesive) As an emulsified monomer mixture, 2-ethylhexyl acrylate: 330 parts Acrylic acid: 30 parts Vinyl acetate: 20 parts Methyl methacrylate: 20 parts Anionic emulsifier (trade name: Emar NC-35 / Kao Corporation): 6 parts, ion-exchanged water: 150 parts, were mixed and prepared. Next, 2.7% by mass of polyethylene glycol dimethacrylate (trade name: NK ester 9G / manufactured by Shin-Nakamura Chemical Co., Ltd.) and polypropylene glycol (manufactured by Wako Pure Chemical Industries /
(Average molecular weight: 1000): prepared by adding 4% by mass. Then, a flask equipped with a stirrer, a cooler, a dropping funnel, a nitrogen suction pipe, and a thermometer was charged with ion-exchanged water: 15
After charging 0 parts and potassium persulfate: 2 parts, the temperature was raised to 80 ° C. while purging with nitrogen, and the above-mentioned monomer mixture was dropped by １ ／. When the reaction rate reached 90%, the remaining emulsified monomer mixture was dropped over 3 hours to carry out polymerization. After completion of the dropwise addition, the mixture was aged at 80 ° C. for 3 hours to complete the reaction.
After completion of the reaction, a neutralization reaction was performed by adding 50 mol% of the carboxyl groups in the copolymer with a 10% aqueous KOH solution. Further, 4 parts of triethanolamine was added to 100 parts of the adhesive, and vigorously stirred to produce an adhesive used in the present invention.

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive was used.

An adhesive tape was produced in the same manner as in Example 1 except that the above-mentioned adhesive was used.

Comparative Example 6 A commercially available acrylic pressure-sensitive adhesive (trade name: Nicazole L-145 / manufactured by Nippon Carbide Industry Co., Ltd.) was used as the pressure-sensitive adhesive to a dry mass of 22 g / m ² and dried. ,
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1.

Comparative Example 7 (Production of adhesive) Natural rubber (RSS # 3): 100 parts,
Petroleum resin (trade name: Quinton S-
100 / manufactured by Zeon Corporation): 90 parts, terpene-based liquid softening resin as a softening agent (trade name: Daimaron / Yasuhara Chemical Co., Ltd.): 25 parts, cross-linking agent (trade name: Millionate MR-100 / manufactured by Nippon Polyurethane Co., Ltd.), A composition comprising an antioxidant (trade name: Nocrack NS-5 / Ouchi Shinko Chemical Co., Ltd.) was dissolved in toluene to prepare an adhesive.

(Preparation of tape base material) 73 g of commercially available rice tsubo
/ M ² kraft paper (trade name: Melamine Clupak / Oji Paper Co., Ltd.), a 20 μm polyethylene film is laminated, and a solvent type silicone release agent (trade name: SD-7220 / Toray Dow) is formed on the polyethylene laminate. Corning): 100 parts, catalyst (trade name: SRX-)
212 / manufactured by Dow Corning Toray): 0.6 part was coated and heat-cured so that the dry weight was 1.0 g / m ² . (Preparation of pressure-sensitive adhesive tape) The pressure-sensitive adhesive was coated on the back surface of the tape base provided with the release agent layer so as to have a dry mass of 40 g / m ² and dried, and then separated from the pressure-sensitive adhesive layer. The above tape base material was bonded to the release agent layer surface to form an adhesive tape.

The pressure-sensitive adhesive sheets and the pressure-sensitive adhesive tapes thus obtained were evaluated as described below, and the results obtained are shown in Tables 1 and 2.

(Evaluation Test Items) [Evaluation of Adhesive Performance] After the production of the adhesive sheet and the adhesive tape, they were stored for 7 days in an atmosphere at a temperature of 23 ± 2 ° C. and a relative humidity of 65 ± 5%.
Adhesive performance was measured in accordance with “Testing method for adhesive tape / adhesive sheet” specified in SZ-0237, and evaluated according to the following evaluation criteria. ：: shows sufficient adhesiveness. Δ: Adhesion is slightly inferior, but practical. ×: No tackiness.

[Swelling Ratio] The produced pressure-sensitive adhesive was applied to a commercially available polyethylene laminated release paper so as to have a dry mass of 25 g / m ² , dried, and used as samples. Four samples cut into about 5 cm square were prepared. (Measurement of thickness of adhesive layer before immersion in water) A polyethylene terephthalate film (PET) was placed on the adhesive layer side of one sample.
, And the thickness was measured. Then, another pressure-sensitive adhesive layer was swollen with toluene and scraped off, PET was superposed and the thickness was measured, and the thickness of the pressure-sensitive adhesive layer before immersion in water was measured from the difference. (Measurement of the thickness of the pressure-sensitive adhesive layer after immersion in water) For one sample, the pressure-sensitive adhesive layer was swollen with toluene and scraped off.
C. in tap water for 10 minutes. For the sample in which the pressure-sensitive adhesive layer has swollen, PET is placed on the pressure-sensitive adhesive layer side, the thickness is measured, and then a sample in which another pressure-sensitive adhesive layer has been scraped in advance is used for PET.
And the thickness was measured, and the thickness of the pressure-sensitive adhesive layer after immersion in water was measured from the difference. The swelling ratio of the pressure-sensitive adhesive layer was calculated as a quotient of the pressure-sensitive adhesive layer thickness before immersion in water before immersion in water. (Unit: times)

[Particle size] In a removable container of a TAPPI standard disintegrator described in Appendix A of JIS-P-8220, 1200 ml of water and 50 g of an air-dried paper / adhesive stored under the following two conditions were used. / A pressure-sensitive adhesive sheet composed of a release paper is put as a sample, and disintegrated for 30 minutes to prepare a suspension of the pressure-sensitive adhesive sheet. This suspension is filtered through a 60-mesh nylon screen, and the filtrate is filtered with a particle size distribution analyzer (SK). LAS
ER MICRON Sizer PRO-7000S
/ Manufactured by Seishin Enterprise Co., Ltd.) to measure the mass average particle diameter of the pressure-sensitive adhesive after redispersion. (Unit: μm) Condition A: After the production of the pressure-sensitive adhesive sheet and the pressure-sensitive adhesive tape, the temperature was 2
After storing for 7 days in an atmosphere at 3 ± 2 ° C. and a relative humidity of 65 ± 5%, the particle size of the adhesive layer after redispersion was measured. Condition B: temperature 4 after production of the pressure-sensitive adhesive sheet and pressure-sensitive adhesive tape
After storing for 7 days in an atmosphere of 0 ± 2 ° C. and relative humidity of 90 ± 5%, the particle size of the adhesive layer after redispersion was measured.

[Measurement of Glass Transition Temperature of Adhesive] After the production of the adhesive sheet and the adhesive tape, the adhesive sheet and the adhesive tape were stored for 7 days in an atmosphere at a temperature of 23 ± 2 ° C. and a relative humidity of 65 ± 5%. The pressure-sensitive adhesive layer is swollen with an organic solvent such as toluene or methyl ethyl ketone, scraped off from the substrate, and after evaporating the organic solvent, a differential scanning calorimeter (DS) is used.
C22 / Seiko Denshi Kogyo). (Unit: ° C)

[Box loop of adhesive tape] JIS-
Class A 280 g / m ² liner specified in P-3902, and Class A 125 g / m specified in JIS-P-3904
A class A corrugated cardboard having a thickness of 5 mm and having a semi-core of ² is cut at a right angle in a width of 50 mm and a length of 200 mm, and 50 mm from both ends are compressed from the back surface to form a folding test piece.
Two tapes were sampled by overlapping them, and the width was 25 in the vertical direction.
mm, cut into 150 mm length. The above-mentioned tape is stuck on the folded cardboard test piece, and the pressure is applied by one reciprocation of a 500 g pressure roll. Immediately after the crimping, a cut is made in a portion 25 mm from both ends of the cardboard so that the area in contact with the cardboard becomes 25 mm × 50 mm. The tape was left in an atmosphere of a temperature of 23 ± 2 ° C. and a relative humidity of 65 ± 5%, and the peeling of the tape after one day was evaluated according to the following evaluation criteria. ：: Does not peel. ：: There is a deviation although it is not peeled. ×: Peeled.

[Water washability] After the production of the pressure-sensitive adhesive sheet, the temperature was 23
The sample was stored for 7 days in an atmosphere at ± 2 ° C. and a relative humidity of 65 ± 5% to obtain a measurement sample. Using a polypropylene plate as an adherend, a sample of 2.5 cm square was attached and 65
The sample was immersed in warm water at ℃ and the time until the sample was peeled was measured and evaluated according to the following criteria. ：: The adhesive label comes off in less than 15 minutes. ×: The adhesive label does not fall off even after 15 minutes or more.

[Recyclability] The recyclability after storage under the following two conditions was evaluated. Condition A: temperature 2 after production of the pressure-sensitive adhesive sheet and pressure-sensitive adhesive tape
After being stored for 7 days in an atmosphere at 3 ± 2 ° C. and a relative humidity of 65 ± 5%, its recyclability was evaluated. Condition B: temperature 4 after production of the pressure-sensitive adhesive sheet and pressure-sensitive adhesive tape
After being stored for 7 days in an atmosphere at 0 ± 2 ° C. and relative humidity of 90 ± 5%, its recyclability was evaluated. (Preparation of Evaluation Samples) Adhesive Sheets of Examples 1 to 6 and Comparative Examples 1 to 7 Assuming an address label to be used by sticking to an envelope, the release sheet was peeled off from the adhesive sheet to form an adhesive label. And affixed to a commercially available high quality paper of 64 g / m ² of rice tsubo to obtain an evaluation paper charge. Similarly, assuming that the pressure-sensitive adhesive tape was used by being pasted on a packaging material capable of recycling used paper, a pressure-sensitive adhesive tape was pasted on a high-quality paper of 64 g / m ² of commercial rice tsubo, and was used as a sample for evaluation. Examples 1 to 6 and Comparative Examples 1 to 6 The adhesive sheet itself was used as an evaluation sample, assuming recycling of used paper in the form of an adhesive sheet including a release sheet.

(Evaluation) To 45 g of a sample cut into a size of about 20 mm square, 1500 ml of water was added, and 1 g of NaOH was further added to the TAPPI disintegrator (3000 rpm).
m) for 30 minutes, and then dehydrated with a 60 mesh nylon screen until the pulp concentration becomes 15%.
1.5 g of an 8% NaOH aqueous solution and 1.8% of a 10% solution of a deinking agent (trade name: DI-600, manufactured by Kao Corporation)
g each, left at 40 ° C. for 20 minutes, then dehydrated with a 60 mesh nylon screen until the pulp concentration became 25%, 3.85 g of a 30% aqueous NaSiO ₃ solution, 6% H ₂ H ₂ 5 g each of O ₂ water was added,
Next, kneading treatment was performed for 5 minutes with a double-armed kneader. After stirring for 120 minutes while maintaining the temperature at 55 ° C., the mixture was diluted with water until the pulp concentration reached 17.5%.
The same kneading process was performed. Thereafter, the mixture was further diluted with water until the pulp concentration became 1%. Next, this 1
The pulp dispersion having a concentration of 10% is floated and separated by a flotator for 10 minutes, bubbles generated at that time are removed by a scraper, dewatered again with a 60-mesh nylon screen, and washed with 1000 ml of water to become 13% concentration. Dehydrated until. Water was added to the pulp dispersion thus obtained to a concentration of 0.3% to prepare a handsheet. Next, the hand-made sheet was sandwiched between high-quality papers of commercially available rice tsubo 64 g / m ² and pressed at 165 ° C. and 1.37 MPa for 1 minute, and the remaining adhesiveness was determined according to the following evaluation criteria.

(Evaluation Criteria for Recycling Suitability) ：: No tackiness at all. Δ: Slight adhesion remains. X: The high quality paper and the handmade sheet are adhered to each other by the adhesive foreign matter, and when the high quality paper is to be peeled off, the high quality paper or the handmade sheet is broken.

[0116]

[Table 1] * In the table, recyclability is the result of evaluation for each case of pressure-sensitive adhesive label / pressure-sensitive adhesive sheet.

[0117]

[Table 2]

[0118]

As shown in Tables 1 and 2, the pressure-sensitive adhesive sheet and the pressure-sensitive adhesive tape of the present invention have excellent recyclability of pulp because the pressure-sensitive adhesive is easily re-dispersed in water, and have the necessary adhesion at the time of application. The pressure-sensitive adhesive sheet and the pressure-sensitive adhesive tape were easily removed to the outside of the process even when they were attached to a packaging material or the like, or when the pressure-sensitive adhesive sheet was mixed in the recycling process.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J004 AA05 AA08 AA10 AB01 CA02 CA04 CB02 CC02 CC03 CD01 CD03 CD05 DB02 FA01 FA06

Claims (8)

[Claims] 1. A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer provided on a surface substrate and a release sheet laminated on the pressure-sensitive adhesive layer in a releasable manner, or a pressure-sensitive adhesive comprising a release agent layer on the substrate surface and a pressure-sensitive adhesive layer on the back surface. In the tape, the swelling ratio of the pressure-sensitive adhesive layer to water is 1.5 times or more, and defibrated with a TAPPI standard disintegrator for 30 minutes.
An adhesive sheet or an adhesive tape, wherein the redispersed adhesive layer has an average particle size of 65 μm or less. 2. The adhesive has a glass transition temperature of -70 to -4.
The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to claim 1, wherein the temperature is 0 ° C. 3. The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive copolymer composition contains a copolymerizable hydrophilic component in an amount of 10 to 30% by mass. 4. The method of claim 1, wherein at least one of (poly) alkylene glycol di (meth) acrylate, (poly) alkylene glycol mono (meth) acrylate, (poly) ethylene glycol and (poly) propylene glycol is used during the copolymerization of the pressure-sensitive adhesive. The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to any one of claims 1 to 3, which is a pressure-sensitive adhesive obtained by copolymerization in the presence of one kind. 5. The method according to claim 1, wherein the (Poly) alkylene glycol di (meth) acrylate or (poly) alkylene glycol mono (meth) acrylate used in the copolymerization of the pressure-sensitive adhesive has 1 to 23 moles of alkylene glycol. The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape is a pressure-sensitive adhesive sheet. 6. The (poly) alkylene glycol di (meth) acrylate used at the time of copolymerization of the pressure-sensitive adhesive is polyethylene glycol dimethacrylate, and the amount thereof is 0.1 to 5% by mass based on the total monomer mixture. The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape according to any one of claims 1 to 5, wherein 7. The amount of (poly) ethylene glycol and / or (poly) propylene glycol used during the copolymerization of the pressure-sensitive adhesive is 0.1 to 0.1% of the total monomer mixture.
The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive sheet has a content of about 15% by mass. 8. The method according to claim 1, wherein the amount of the (poly) alkylene glycol mono (meth) acrylate is from 0.1 to 5% by mass based on the total monomer mixture.
8. The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to claim 7.