JP2001172580A - Pressure sensitive adhesive sheet or pressure sensitive adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensitive adhesive sheet or a pressure sensitive adhesive tape which can be easily redisintegrated without being peeled in advance in obtaining a regenerated pulp and without suffering adverse influence by a pressure sensitive adhesive, regenerated as a pulp by an ordinary pulp regeneration process without contaminating adjusting water used in disintegration and qualitatively stably recycled. 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 base paper of the surface substrate or the tape substrate comprises a substrate disintegrable by water or an aqueous alkali solution and having a paper layer pH of 6 or lower, and the pressure sensitive adhesive layer comprises a pressure sensitive adhesive exhibiting redispersibility in water and composed of an acrylic copolymer having a glass transition temperature ranging from -70 to -40 deg.C. The pressure sensitive adhesive layer of the pressure sensitive adhesive sheet or the pressure sensitive adhesive tape 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.

On the other hand, 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 producing paper and paperboard. Occupy the position. Recycled pulpable paper is newspaper, cardboard, magazine, imitation, color (including art), white, card, special white, medium white, white manila, ticket, Nakashiro antique, tea imitation paper (Western style) ), Mounts, balls, OCR paper and the like. In general, waste paper goes through a defibration process to disintegrate the pulp suspension to obtain a pulp suspension, a rough selection process to separate foreign substances in the pulp suspension, a fine selection process, a deinking process to separate printing ink, and a bleaching process to whiten the color. Recycling pulping is performed.

As a method of using an adhesive sheet or an adhesive tape, for example, the adhesive sheet is composed of slips which are bound as an appendix to 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 pasted on cardboard as a delivery slip for home delivery. Recently, it is also used for stamps and other stamps. In addition, the adhesive tape
It is mainly used for packing cardboard and 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.

However, waxed paper, pressure-sensitive adhesive sheets, pressure-sensitive adhesive labels, pressure-sensitive adhesive tapes and the like cannot be used to separate water-insoluble waxes and pressure-sensitive adhesives from pulp fibers and are considered to be difficult to recycle into pulps. I have. 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,
In order to make it easy for stamp collectors to peel off stamps from substrates such as envelopes, there is a water release layer on the back of the stamp paper that can be peeled off in water, but the adhesive remains on the substrate Therefore, it is difficult to regenerate these base materials into pulps.

[0008] When paper is made using recycled pulp containing an adhesive component, the 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 paper layers or quality is adversely affected, such as a problem of lowering or formation of spots on the paper surface.

Furthermore, since the release sheet or the base material for the adhesive tape used for the adhesive sheet is a base material having a low disintegration property such as a laminated paper obtained by laminating polyethylene, the use of recycled pulping is more difficult. Have difficulty. 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.

[0010] Recently, there have been reported a number of cases in which adhesive products that cannot be recycled as described above have been successfully recycled by devising them physically or by equipment, due to problems such as forest resources and environmental protection. 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 is soluble in water or alkaline water has 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.

[0012]

DISCLOSURE OF THE INVENTION The present invention relates to a method for obtaining recycled pulp from an adhesive sheet, an adhesive label, a packaging base material to which an adhesive tape is attached, or a corrugated cardboard without removing the adhesive label or the adhesive tape in advance. Adhesives can be easily re-disintegrated without adverse effects, can be regenerated as pulp in the normal re-pulp process without contaminating the conditioned water during disintegration, and can be recycled with stable quality It is to provide a possible adhesive sheet or adhesive tape.

[0013]

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 a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer provided on the back surface, the base paper of the surface base material or the tape base material is a base material having a paper layer pH of 6 or less that can be disintegrated with water or an alkaline aqueous solution, and the pressure-sensitive adhesive layer is Pressure-sensitive adhesive sheet having a glass transition temperature in the range of -70 to -40 ° C, comprising an acrylic copolymer having a redispersibility. It is a tape.

Further, the present invention provides (2) forming the pressure-sensitive adhesive layer with TA
The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to (1), wherein the redispersed pressure-sensitive adhesive layer has an average particle size of 65 μm or less when defibrated by a PPI standard defibrating machine for 30 minutes. (3) The adhesive contains a copolymerizable hydrophilic component in an amount of 10 to 30.
The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape according to (1) or (2), which is contained by mass%. (4) The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive sheet according to any one of (1) to (3), wherein the pressure-sensitive adhesive is a pressure-sensitive adhesive that copolymerizes methyl methacrylate as an essential component in its monomer composition. It is an adhesive tape. (5) The pressure-sensitive adhesive is (poly) alkylene glycol di (meth) acrylate, (poly) alkylene glycol mono (meth) acrylate, (poly)
Any one of (1) to (4), which is an adhesive obtained by copolymerization in the presence of at least one of ethylene glycol and (poly) propylene glycol.
A pressure-sensitive adhesive sheet or a pressure-sensitive adhesive tape according to (1). (6) The (mol) addition alkylene glycol of (poly) alkylene glycol di (meth) acrylate or (poly) alkylene glycol mono (meth) acrylate used in the copolymerization of the pressure-sensitive adhesive is 1 to 23. The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape according to any one of (1) to (5). (7) The (poly) alkylene glycol di (meth) acrylate added 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 and the pressure-sensitive adhesive tape according to any one of (1) to (6). (8) The amount of (poly) ethylene glycol and / or (poly) propylene glycol used during the copolymerization of the pressure-sensitive adhesive is 0.1 to 15% 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 (7). (9) The amount of the (poly) alkylene glycol mono (meth) acrylate used in the copolymerization of the pressure-sensitive adhesive 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 (8).

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the present invention provides a pressure-sensitive adhesive sheet and a pressure-sensitive adhesive tape which are extremely easy to be recycled and pulped, because the pressure-sensitive adhesive layer is made of a pressure-sensitive adhesive having particularly excellent redispersibility in water. Things. Then, in order to obtain such a recyclable pressure-sensitive adhesive sheet and pressure-sensitive adhesive tape, the surface substrate of the pressure-sensitive adhesive sheet or the tape substrate is made of a paper layer disintegratable with water or an aqueous alkaline solution (or a paper layer if there is no coating layer). Acrylic copolymer having a pH of 6 or less, the pressure-sensitive adhesive having redispersibility in water, and having a glass transition temperature in the range of -70 to -40 ° C. The feature is that it is an adhesive consisting of Generally, paper is roughly classified into acidic paper and neutral paper according to the papermaking conditions. Acidic paper means that a sizing agent or the like added during papermaking exerts its effect in the acidic region, and a sulfuric acid band is generally used for fixing the paper, and the pH of the paper layer (paper surface) is in the range of 4 to 6. It is adjusted by. On the other hand, neutral paper is a paper that is made in the neutral region by neutralizing by a chemical treatment during papermaking or a size prescription that does not use a sulfuric acid band, and its paper layer (paper surface) pH Is generally adjusted in the range of more than 6 and 8 or less. Further, since no sulfate band is used, calcium carbonate is often used as the internal filler.

The water-redispersible pressure-sensitive adhesive is characterized in that it contains more hydrophilic components in its composition than general-purpose pressure-sensitive adhesives. Among the hydrophilic components, compounds having a carboxyl group are particularly preferred. It has been generally considered that when paper containing or coated with calcium carbonate is used as the surface substrate, the paper is crosslinked by the calcium ions and the pressure-sensitive adhesive deteriorates with time. However, the inventors have found that even with paper coated with calcium carbonate on the base material, the water redispersible adhesive may not deteriorate, and the water redispersible adhesive may affect the effect of calcium carbonate. Deterioration with time is caused by the paper layer (hereinafter also referred to as the paper surface) of the base paper in contact with the adhesive layer.
H was found to be significantly related. That is, in the case of paper having a neutral pH, the compound having a carboxyl group is likely to become a carboxy ion and is easily affected by calcium ions. It is considered that the compound having a group hardly becomes a carboxy ion.

The surface substrate capable of being disintegrated with water or an alkaline aqueous solution used for the adhesive sheet includes high-quality paper, art paper, coated paper, cast paper, kraft paper, impregnated paper, low-size paper, water-soluble paper, or kraft paper. Or on high-quality paper, for example, casein, dextrin, starch, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose, polyvinyl alcohol, styrene-butadiene copolymer, methylmethacrylate-butadiene copolymer, ethylene-vinyl chloride copolymer, ethylene -A base material provided with a filler layer mainly containing a natural or synthetic resin such as a vinyl acetate copolymer or an acrylate copolymer and / or a pigment can be used.

Next, as a base material that can be disintegrated with water or an alkaline aqueous solution used for the adhesive tape, clay-coated paper,
For example, casein, dextrin, starch, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose, polyvinyl alcohol, styrene-
A natural or synthetic resin and / or pigment such as butadiene copolymer, methyl methacrylate-butadiene copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, acrylate copolymer, etc. And a substrate provided with a sealing layer.

The filler layer containing a resin and / or a pigment as a main component is not particularly limited. For example, casein, dextrin, starch, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose, polyvinyl alcohol, styrene- Butadiene copolymer, methyl methacrylate
Butadiene copolymer, ethylene-vinyl chloride copolymer,
Natural or synthetic resins such as acrylic ester copolymers and / or inorganic pigments such as kaolin, calcium carbonate, clay, talc, calcined kaolin, delamikaolin, titanium dioxide, aluminum hydroxide, silica, white carbon, or polystyrene resin fine particles Organic synthetic pigments such as urea-formalin resin fine particles and fine hollow particles can be used. In addition to the base material provided with the filler layer, for example, art paper, coated paper, cast coated paper, etc.
A base material having a printing coating layer containing a pigment as a main component on the surface of paper 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 filling layer coating liquid containing such a resin and / or a pigment as a main component is usually used in a coating solution such as a blade coater, a bar or rod coater, an air knife coater, a gravure coater, a roll coater, a die coater, and a lip coater. 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 .

As the surface substrate or the pressure-sensitive adhesive tape substrate of these pressure-sensitive adhesive sheets, it is necessary to use paper having a paper surface pH of 6 or less. This is because in the area where the paper pH is higher than 6,
The hydrophilic component in the pressure-sensitive adhesive having redispersibility in water, particularly a compound having a carboxyl group, is easily affected by calcium carbonate and the like contained in the paper or the coating layer of the coated paper. This is because they deteriorate over time. In addition,
When measuring the pH of the paper, the surface fiber of the paper is peeled off with a cellophane tape or the like, and the coated paper with a pigment coating layer on the paper is also measured with a cellophane tape. Peel off the pigmented coating layer to expose the base paper layer, drop a commercially available test solution (pH meter for paper surface measurement / Kyoritsu Rikagaku Kenkyusho) that changes color according to pH, lightly wipe it off with a cloth, and compare it with the standard color. Ask for color. The base material provided with the filler layer can be similarly confirmed.

Next, the pressure-sensitive adhesive used in the pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape of the present invention is an acrylic copolymer having redispersibility in water and a glass transition temperature in the range of -70 to -40 ° C. An adhesive consisting of

In order to obtain a pressure-sensitive adhesive having redispersibility in water, it is indispensable to incorporate a hydrophilic monomer into the pressure-sensitive adhesive composition. The glass transition temperature of the coalescence increases, and sufficient 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 −70 to −40.
It is necessary to prepare an adhesive by blending various monomers so as to be in the range of ° C, more preferably in the range of -70 to -45 ° C. The glass transition temperature of the pressure-sensitive adhesive referred to here is
This is a value measured by a differential scanning calorimeter after the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape is swollen with an organic solvent such as toluene and scraped off from the substrate to volatilize the organic solvent. (Unit: ° C)

Incidentally, the glass transition temperature of the adhesive is -70.
When the temperature is lower than ℃, the water redispersibility of the obtained pressure-sensitive adhesive film is impaired. On the other hand, when the temperature exceeds -40 ° C, the pressure-sensitive adhesive film obtained becomes hard and has poor practicality.

In the pressure-sensitive adhesive layer, it is preferable that the pressure-sensitive adhesive layer redispersed after being defibrated with a TAPPI standard disintegrator for 30 minutes has an average particle diameter of 65 μm or less. Incidentally, if the average particle diameter of the pressure-sensitive adhesive particles after redispersion is larger than 65 μm,
Adhesive particles remain in the pulp, causing sticking troubles in the papermaking process and deteriorating product quality.
The TAPPI standard disintegrator referred to here is JIS-P-
A device described in Annex A of 8220, in which a removable container contains 1200 ml of water and air-dried adhesive sheet or adhesive tape composed of 50 g of paper / adhesive / peel paper, and 70 g of commercially available rice tsubo. / M ² of high-quality paper as a sample, put it into a sample, disassemble it into 30 to make a suspension of adhesive sheet or adhesive tape, filter this suspension through a 60 mesh nylon screen, and Was subjected to a particle size distribution meter to measure the average particle size of the pressure-sensitive adhesive particles after redispersion.

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 ethylenically unsaturated monomers such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, monoalkylmaleic acid, monoalkylitaconic acid and monoalkylfumaric acid. Carboxylic acid-containing monomer, alkoxyalkyl (meth) acrylate such as methoxyethyl acrylate, ethoxyethyl acrylate, carboxylic acid modified rosin ester, caprolactone adduct of (meth) acrylic acid, hydroxyethyl (meth) acrylate, (meth) acrylic acid Examples include hydroxypropyl, (meth) acrylamide, dimethylaminoethyl (meth) acrylate, and diethylaminoethyl (meth) acrylate.

These compounds can be suitably used in consideration of the balance of hydrophilicity, water redispersibility and adhesive performance of the adhesive. And these monomers are copolymers of 10 to 30.
It is desirable that the polymerization is carried out 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.

Examples of the copolymerizable monomer other than the above-mentioned hydrophilic monomer include, for example, butyl (meth) acrylate and (meth) acrylate as components for imparting the tackiness of the pressure-sensitive adhesive.
Hexyl acrylate, octyl (meth) acrylate,
2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate and the like, and as components for adjusting the adhesive performance, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, ( Examples include cyclohexyl (meth) acrylate, glycidyl (meth) acrylate, vinyl acetate, vinyl propionate, vinyl chloride, styrene, and ethylene.

Of these other copolymerizable monomers, the use of methyl methacrylate is more preferable because a copolymer having a suitable glass transition temperature, adhesive performance, redispersibility and the like can be obtained.

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 thereof include tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and polypropylene glycol di (meth) acrylate.

[0034]

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 the above copolymer is produced in the presence of an acrylate, the hydrophilicity can be imparted to the pressure-sensitive adhesive and the molecular weight can be increased at the same time, so that the particles after redispersion become hard, and the particles remaining in the recycling step become sticky in water. It is preferable because it does not exhibit the property.

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.

The (poly) alkylene glycol di (meth) acrylate is desirably 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, when it exceeds 5% by mass, the pressure-sensitive adhesive is likely to aggregate.

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.

[0039]

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 made hydrophilic at the same time as 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 is preferably 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 may be insufficient. On the other hand, if it exceeds 5% by mass, the cohesive force of the pressure-sensitive adhesive may decrease. Also,
When the addition mole number of the alkylene glycol of 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 remain in the recycling process. The particles develop tackiness in water, which can adversely affect paper layer formation or quality during paper recycling.

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

[0043]

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 hydrophilic property can be imparted to the pressure-sensitive adhesive, so that the copolymer is excellent in hydrophilicity and film swelling property. Is obtained, and an adhesive suitable for recycling with good water redispersibility can be produced.

The (poly) ethylene glycol and / or (poly) propylene glycol is 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. Is preferred.
By the way, if it is less than 0.1% by mass, the water redispersibility of the pressure-sensitive adhesive may be insufficient. On the other hand, if it exceeds 15% by mass, the viscosity tends to increase, and the handleability of the pressure-sensitive adhesive may decrease.

In order to further improve the tackiness and hydrophilicity of these copolymers, the carboxyl groups contained in the copolymer may be neutralized by one or more alkaline substances. Examples of the alkaline substance include monoethanolamine, diethanolamine, triethanolamine, propanolamine, β-propanolamine, tripropanolamine, isopropanolamine, triisopropanolamine, 2-aminoisohexyl alcohol, N-methyldiethanolamine, N, N- Examples thereof include alkanolamines having a boiling point of 100 ° C. or more such as dibutylethanolamine, hydroxides of alkali metals such as potassium hydroxide and sodium hydroxide, ammonia, and lower amines. Among these alkaline substances, alkanolamines and potassium hydroxide having a boiling point of 100 ° C. or more are more preferable because carboxyl groups can be stably neutralized even after the step of coating and drying the pressure-sensitive adhesive. These alkaline substances are preferably added so as to correspond to 50 to 120 mol% of the carboxyl groups in the copolymer.

Further, a hydrophilic plasticizing substance may be added in order to adjust the physical properties of the pressure-sensitive adhesive and to prevent discoloration and deterioration of the pressure-sensitive adhesive over time. Examples of hydrophilic plasticizers include sugar alcohols such as glycerin, sorbit, mannitol, dursit, idit, erythrit, arabit, adnit, polyethylene oxide or polypropylene oxide and glycerin, xylitol trioxyisobutane, and sorbit. Copolymers with polyhydric alcohols, polyether polyols such as polyethylene glycol and polypropylene glycol, copolymers of ethylene oxide and propylene oxide, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polyoxy Nonionic surfactants such as propylene glycol are exemplified. This substance is preferably used in an amount of 10% by mass or less, more preferably 0.5 to 10% by mass, based on the copolymer, in consideration of tackiness and water redispersibility.

[0048] Among these hydrophilic plasticizing substances, nonionic surfactants are particularly preferred because they can finish a pressure-sensitive adhesive having good adhesiveness and storage stability.

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 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
It 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. These substances are desirably added to the copolymer in an amount of 3 to 30% by mass in consideration of the balance between tackiness and water redispersibility.

According to the present invention, by using such a copolymer as an adhesive, an adhesive sheet and an adhesive tape which can be mixed in a waste paper recycling step can be obtained.

Next, as a material used as a release sheet substrate of the pressure-sensitive adhesive sheet, high-density base paper such as glassine paper, clay-coated paper, glassine paper, kraft paper or woodfree paper, etc.
For example, casein, dextrin, starch, carboxymethylcellulose, methylcellulose, ethylcellulose,
Hydroxyethyl cellulose, polyvinyl alcohol,
Natural or synthetic resins and / or pigments such as styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, acrylate copolymer, etc. A base material provided with a filler layer as a component, laminated paper (poly-laminated paper) obtained by laminating polyethylene or the like on glassine paper, kraft paper, or high-quality paper, polypropylene,
Films such as polyester can be used.

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 kraft paper or kraft paper can be used. , 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 as the release sheet, it is desirable to use paper having a paper layer pH of 6 or less.

The filler layer containing a resin and / or a pigment as a main component is not particularly limited. For example, casein, dextrin, starch, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose, polyvinyl alcohol, styrene- Butadiene copolymer, methyl methacrylate
Butadiene copolymer, ethylene-vinyl chloride copolymer,
Natural or synthetic resins such as acrylate copolymers and / or inorganic pigments such as kaolin, calcium carbonate, clay, talc, calcined kaolin, delamikaolin, titanium dioxide, aluminum hydroxide, silica, white carbon, or polystyrene resin fine particles Organic synthetic pigments such as urea-formalin resin fine particles and fine hollow particles can be used.

In addition to the base material provided with the filling layer, a printing coating layer containing a pigment as a main component was provided on the paper surface, such as art paper, coated paper, cast coated paper, or the like. 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 base material. 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 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 commonly used in a water-dispersed type, a solvent type or a non-coated 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 recent years, tapes without release paper have been developed as one form of adhesive labels from the viewpoint of resource saving. In this case, printing of printing paper such as art paper or coated paper is performed. The surface is provided with a releasable printed layer, and such a layer may be used instead of the release agent layer.

In the method of forming the pressure-sensitive adhesive sheet, a pressure-sensitive adhesive is usually applied 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 substrate provided with the release agent layer or the release-printable layer, and drying to provide 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 usually adjusted to a viscosity of 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.

[0066]

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. Unless otherwise specified, all parts, ratios, coating amounts, and the like in the examples are based on the solid content or the mass of the active ingredient.

Example 1 (Production of pressure-sensitive adhesive) First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 250 parts Acrylic acid: 35 parts Methyl methacrylate: 20 parts Methoxyethyl acrylate: 75 parts Vinyl acetate: 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 3 parts 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, 50% by mole of a carboxyl group in the copolymer is added with triethanolamine and a 10% aqueous KOH solution to carry out a neutralization reaction, and 100 parts of the adhesive is subjected to a nonionic surfactant (commercially available). Name: Emulgen 810
/ Manufactured by Kao Corporation): 4 parts were added, and the mixture was vigorously stirred to produce an adhesive used in the present invention.

(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.

[0071] (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 applied 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 A pressure-sensitive adhesive sheet and a pressure-sensitive adhesive tape were produced in the same manner as in Example 1, except that the following substrates were used as the surface substrate and the tape substrate.

(Preparation of Surface Base Material and Base Material for Adhesive Tape) As a coating liquid, kaolin (trade name: UW-90 / E) was used.
MC): 45 parts, calcium carbonate (trade name: Brilliant S-15 / Shiraishi Kogyo): 55 parts, latex (trade name: L-1392 / Asahi Kasei Corporation): 21 parts, casein (trade name: Arashid / New Zealand Casein): 5.43 parts, dispersant (trade name: Nancarin S-)
1 / Rin Kagaku Co., Ltd.): 0.0675 parts, defoamer (trade name:
Bismer FX-10 / Nisshin Chemical Co., Ltd.): 0.3 part, release agent (trade name: Hydrin Z-8 / Chukyo Yushi Co., Ltd.) 0.8
Parts, zinc sulfate: 3 parts by weight, a solid content of 47 parts
%, And a commercially available rice tsubo 64 g / m ²
Coated on a high-quality paper having a dry weight of 25 g / m ² ,
Dry and smooth finish with a super calender,
By the rewet method, while the coating layer is in a wet state,
The surface of the coating layer was pressed against a heated metal drum to perform a cast finish to obtain a substrate.

Next, a solvent-free silicone release agent (trade name: LTC-1) was applied on the pigment coating layer of the substrate thus obtained.
073L / Dow Corning Toray Co., Ltd.): 100 parts, catalyst (trade name: LTC-1100M / Dow Corning Toray Co., Ltd.): 10 parts, coated so as to have a dry mass of 1.0 g / m ^2, and heat cured. And used as a substrate for an adhesive tape.

Example 3 A pressure-sensitive adhesive sheet and a pressure-sensitive adhesive tape were produced in the same manner as in Example 1, except that the following base materials were used as the surface base material and the tape base material.

(Preparation of Surface Base Material and Base Material for Adhesive Tape) As a coating liquid, kaolin (trade name: UW-90 / E) was used.
MC): 70 parts, heavy calcium carbonate (trade name: Hydrocarb K-6 / Bihoku Powder Chemical Co., Ltd.): 30 parts, phosphorylated esterified starch (trade name: Neil Gum A-55C / Abebe Co.) : 1 part, oxidized starch (trade name: Ace A / Oji Cornstarch): 8 parts, SBR latex (trade name: T-2257 / Nippon Synthetic Rubber Co.): 8 parts, dispersant (trade name: Alon A) -9 / Toagosei Chemical Industry Co., Ltd.):
A composition consisting of 0.1 part was mixed and prepared so as to have a solid content concentration of 60% to obtain a coating composition. The coating composition thus obtained was coated on a commercially available high-quality paper of 64 g / m ² of rice tsubo to have a dry mass of 20 g / m ² and dried to form a pigment coated layer. Next, gloss finishing was performed with a super calender to finish the surface substrate.

Next, a solvent-free silicone release agent (trade name: LTC-1073L) was applied on the pigment coating layer of the obtained base material.
/ Toray Dow Corning): 100 parts, catalyst (trade name LTC-1100M / Toray Dow Corning):
10 parts were coated so that the dry weight was 1.0 g / m ² ,
It was heat-cured to obtain a substrate for an adhesive tape.

Example 4 (Production of pressure-sensitive adhesive) First, 2-ethylhexyl acrylate: 265 parts Acrylic acid: 20 parts Methyl methacrylate: 20 parts Methoxyethyl acrylate: 75 parts Vinyl acetate: 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). 1. Dimethacrylate (trade name: NK ester A-4G / manufactured by Shin-Nakamura Chemical Co., Ltd.): 0.9% by mass, polypropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd./average molecular weight: 1000):
It was prepared by adding 7% by mass. Next, a copolymer was produced in the same manner as in Example 1, and after the reaction was completed, triethanolamine and a 10% aqueous KOH solution were added to each other to perform 50% by mole of carboxyl groups in the copolymer to perform a neutralization reaction.
Further, 4 parts of a nonionic surfactant (trade name: Emulgen 810 / manufactured by Kao Corporation) was added to 100 parts of the adhesive, and the mixture was vigorously stirred to produce an adhesive used in the present invention.

(Preparation of Surface Substrate and Adhesive Tape Substrate) Kaolin (trade name: Amazon 88 /
50 parts, aluminum hydroxide (trade name: Heidilite H-43 / manufactured by Showa Denko KK): 50 parts,
Latex (trade name: L-1392 / Asahi Kasei Corporation): 2
0 parts, casein (trade name: Alagit / New Zealand casein): 5.43 parts, dispersant (trade name: Alon A-9 / Toagosei Chemical Industry Co., Ltd.): 0.1 part, defoamer (trade name) Name: Bismer FX-10 / Nissin Chemical Co.): 0.
A composition comprising 3 parts of a release agent (trade name: Hydrin Z-8 / manufactured by Chukyo Yushi Co., Ltd.): 0.8 part and zinc sulfate: 3 parts was mixed and prepared so as to have a solid content concentration of 47%. A coating composition was obtained. The coating composition thus obtained was converted to a commercially available rice tsubo 64 g /
coated so that the dry mass in the fine paper of m ² is 25 g / m ^2, dried, subjected to planishing with super calender, the rewetting method, while the coating layer is in a wet state, the the coating The layer surface was pressed into contact with a heated metal drum to perform a cast finish to obtain a surface substrate.

Next, a solvent-free silicone release agent (trade name: LTC-1073L) was applied on the pigment coating layer of the obtained base material.
/ Toray Dow Corning): 100 parts, catalyst (trade name LTC-1100M / Toray Dow Corning):
10 parts were coated so that the dry weight was 1.0 g / m ² ,
It was heat-cured to obtain a substrate for an adhesive tape.

(Preparation of pressure-sensitive adhesive sheet)
A commercially available glassine paper (trade name: blue glassine <73> / manufactured by Abekawa Paper Co., Ltd.) was used, and the obtained adhesive was dried at a dry weight of 2%.
After coating and drying at 5 g / m ² , it was adhered to the above surface substrate to obtain an adhesive sheet.

(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 5 First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 225 parts Acrylic acid: 45 parts Methyl methacrylate: 20 parts Methoxyethyl acrylate: 75 parts Hydroxyethyl methacrylate: 15 parts Vinyl acetate: 20 parts Anion emulsifier (trade name: Emar NC-35 / Kao Corporation): 6 parts Ion-exchanged water: 150 parts Next, a copolymer was produced in the same manner as in Example 1. After the reaction was completed, 50 mol% of the carboxyl group in the copolymer was added to carry out a neutralization reaction. On the other hand, an ethylene-vinyl acetate-acrylic copolymer (trade name: Sumikaflex S-3110 / Sumitomo Chemical Co., Ltd.): 27 parts, a nonionic surfactant (trade name: Emulgen 810 / Kao Corporation): 4 parts Was added and vigorously stirred to produce an adhesive used in the present invention.

(Preparation of Surface Base Material and Tape Base Material) As a coating liquid, kaolin (trade name: Amazon 88 / CAD)
AM Co.): 40 parts, kaolin (trade name: UW-90 /
EMC Co.): 40 parts, aluminum hydroxide (trade name:
Heidilite H-42 / Showa Denko KK: 20 parts, phosphorylated esterified starch (trade name: Neil Gum A-55C /
Abebe Co.): 2 parts, latex (trade name: T-258)
0 / manufactured by Nippon Synthetic Rubber Co., Ltd .: 12 parts, dispersant (trade name: ARON A-9 / manufactured by Toagosei Chemical Industry Co., Ltd.): 0.1 part, so as to have a solid content concentration of 60%. mixture was prepared, the dry mass in the fine paper commercial basis weight 64 g / m ² is 2
It was coated so as to be 0 g / m ² , dried, and gloss-finished with a super calender to obtain a surface substrate.

Next, a solvent-free silicone release agent (trade name: LTC-1073L) was applied on the pigment coating layer of the obtained substrate.
/ Toray Dow Corning): 100 parts, catalyst (trade name LTC-1100M / Toray Dow Corning):
10 parts were coated so that the dry weight was 1.0 g / m ² ,
It was heat-cured to obtain a substrate for an adhesive tape.

(Preparation of pressure-sensitive adhesive sheet)
Using the release sheet prepared in Example 1, the obtained pressure-sensitive adhesive was applied so as to have a dry mass of 25 g / m ² , dried, and then bonded to the surface substrate to obtain a pressure-sensitive adhesive sheet. .

(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 6 (Production of adhesive) First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 285 parts Acrylic acid: 35 parts Methyl acrylate: 20 parts Methoxyethyl acrylate: 40 parts Vinyl acetate: 20 Part Anionic emulsifier (trade name: Emal NC-35 / Kao Corporation): 6 parts Deionized water: 150 parts were mixed, and polyethylene glycol dimethacrylate (trade name: NK Ester 9) was added to the total monomer mixture.
G / manufactured by Shin-Nakamura Chemical Co., Ltd.): prepared by adding 0.9% by mass. Next, a copolymer was produced in the same manner as in Example 1, and after the reaction was completed, triethanolamine and 10% KOH
An aqueous solution was added to each of the copolymers to add 50 mol% of carboxyl groups to carry out a neutralization reaction.
To each part, 4 parts of a nonionic surfactant (trade name: Emulgen 810 / Kao Corporation) was 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 1 Commercially available 100% recycled paper (OK Prince Fine Eco G1) as a base paper provided with a sealing layer of a surface base material and a tape base material
00 / Oji Paper Co., Ltd.), and an adhesive sheet and an adhesive tape were produced in the same manner as in Example 1.

Comparative Example 2 Commercially available 100% recycled paper (OK Prince Fine Eco G1) was used as a base paper provided with a sealing layer of a surface base material and a tape base material.
00 / manufactured by Oji Paper Co., Ltd.), to prepare an adhesive sheet and an adhesive tape in the same manner as in Example 4.

Comparative Example 3 (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.

An adhesive sheet was prepared in the same manner as in Example 2 except that the above-mentioned adhesive was used.

A pressure-sensitive adhesive tape was prepared in the same manner as in Example 2 except that the above-mentioned pressure-sensitive adhesive was used.

Comparative Example 4 A commercially available acrylic pressure-sensitive adhesive (trade name: Nicazole L-145 / manufactured by Nippon Carbide Industry Co., Ltd.) was applied as a pressure-sensitive adhesive to a dry mass of 22 g / m ² and dried. ,
An adhesive sheet was prepared in the same manner as in Comparative Example 1.

Comparative Example 5 (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 pressure-sensitive adhesive tapes thus obtained were evaluated as described below, and the obtained results 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 under the following two conditions, and then subjected to JIS-Z-02.
The adhesive performance was measured in accordance with “Testing methods for adhesive tapes / adhesive sheets” specified in 37, and evaluated according to the following evaluation criteria. ：: shows sufficient adhesiveness. Δ: Adhesion is slightly inferior, but practical. ×: No tackiness. 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 of 3 ± 2 ° C. and a relative humidity of 65 ± 5%, the adhesive strength was measured. 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 a relative humidity of 90 ± 5%, the adhesive strength was measured.

[Measurement of pH of Paper Layer] The surface of the pressure-sensitive adhesive sheet is opposite to the pressure-sensitive adhesive in the case of a base material, and the surface of the pressure-sensitive adhesive tape substrate is swollen and scraped off with an organic solvent, and the surface is coated with cellophane tape. Was peeled off, and a commercially available test solution (pH meter for measuring the paper surface / Kyoritsu Riken Co., Ltd.) that changed color due to pH was applied to the paper layer, and colorimetrically determined with a standard color.

[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 of 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)

[Particle Size] After producing 1200 ml of water, an adhesive sheet and an adhesive tape in a removable container of a TAPPI standard disintegrator described in Appendix A of JIS-P-8220, at a temperature of 23 ± 2 ° C. Air-dried paper equivalent to 50 g / adhesive / stored in an atmosphere of 65 ± 5% humidity for 7 days
A pressure-sensitive adhesive sheet composed of release paper is placed as a sample, and 30
Separate and disassemble to make a suspension of the adhesive sheet, and apply this suspension to 60
The solution is filtered through a mesh nylon screen, and the filtrate is subjected to particle size distribution analyzer (SK LASER 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: μ
m)

[Box loop of adhesive tape] JIS-
A-class 280 g / m2 liner specified in P-3902, and A-class 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.

[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) Examples 1 to 6 and Comparative Examples 1
An adhesive sheet of Comparative Example 5. Assuming an address label to be used by attaching to an envelope, the release sheet was peeled off from the adhesive sheet to form an adhesive label, which was then affixed to a high quality paper of 64 g / m ² of commercial rice tsubo to obtain an evaluation paper charge. Also adhesive tape. Assuming that the adhesive tape was used by being attached to a packaging material capable of recycling used paper, an adhesive tape was attached to a commercially available high quality paper of 64 g / m ² of rice tsubo to obtain a sample for evaluation. Example 1 to Example 6 and Comparative Example 1 to Comparative Example 5. The adhesive sheet itself was used as an evaluation sample, assuming recycled 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, a kneading treatment was performed for 5 minutes using a double-arm kneader. Next, after stirring at 55 ° C. for 120 minutes, the mixture was diluted with water until the pulp concentration reached 17.5%, and then the second kneading treatment was performed in the same manner. 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% was subjected to a flotation treatment with a floatator for 10 minutes, bubbles generated at that time were removed with a scraper, dewatered again with a 60-mesh nylon screen, washed with 1000 ml of water, until the concentration became 13%. Dehydrated. The pulp dispersion obtained in this manner was added to 0.1%.
Water was added until the concentration became 3% to prepare a hand-made sheet. Next, the handmade sheet was sandwiched between commercially available high quality papers of 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) A: No tackiness. Δ: Slight adhesion remains. ×: The high quality paper and the handmade sheet are adhered by the adhesive foreign matter,
Attempting to peel off the woodfree paper breaks the woodfree paper or handmade sheet.

[0112]

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

[0113]

[Table 2]

[0114]

As shown in Tables 1 and 2, the pressure-sensitive adhesive sheet and the pressure-sensitive adhesive tape of the present invention can prevent deterioration of the pressure-sensitive adhesive over time by using paper having a paper layer pH of 6 or less as the surface base material. Easy re-dispersion of water in water makes pulp excellent in recyclability and shows necessary adhesive strength when pasted. Mixes in the recycling process as it is pasted on packaging or as an adhesive sheet However, the adhesive sheet and the adhesive tape were easily removed outside the process.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J004 AA05 AA08 AA10 AB01 CA01 CA02 CA08 CB02 CC02 DA01 DA02 DB02 FA01

Claims (9)

[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 base paper of the surface base material or the tape base material is a paper layer having a pH of 6 or less that can be disintegrated with water or an aqueous alkaline solution, and the pressure-sensitive adhesive layer is a pressure-sensitive adhesive having redispersibility in water. And the glass transition temperature of the adhesive is -70 to -4.
A pressure-sensitive adhesive sheet or a pressure-sensitive adhesive tape, which is a pressure-sensitive adhesive made of an acrylic copolymer in a temperature range of 0 ° C. 2. The pressure-sensitive adhesive layer is applied to a TAPPI standard disintegrator for 30 minutes.
The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to claim 1, wherein the average particle diameter of the re-dispersed pressure-sensitive adhesive layer is 65 µm or less when disintegrated for one minute. 3. The pressure-sensitive adhesive according to claim 1, wherein the copolymerizable hydrophilic component comprises 10
The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive sheet contains 30 to 30% by mass. 4. The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive is a pressure-sensitive adhesive which copolymerizes methyl methacrylate as an essential component in its monomer composition. Adhesive tape. 5. The method according to claim 1, wherein said adhesive is (poly) alkylene glycol di (meth) acrylate, (poly)
The pressure-sensitive adhesive obtained by copolymerizing in the presence of at least one of alkylene glycol mono (meth) acrylate, (poly) ethylene glycol, and (poly) propylene glycol. The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to claim 1. 6. The method according to claim 1, wherein the addition mole number of the alkylene glycol of the (poly) alkylene glycol di (meth) acrylate or the (poly) alkylene glycol mono (meth) acrylate used in the copolymerization of the pressure-sensitive adhesive is from 1 to 23. 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. 7. The (poly) alkylene glycol di (meth) acrylate added at the time of copolymerization of the pressure-sensitive adhesive is polyethylene glycol dimethacrylate, and the amount added is
The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to any one of claims 1 to 6, wherein the content is 0.1 to 5% by mass based on the total monomer mixture. 8. The amount of (poly) ethylene glycol and / or (poly) propylene glycol used in the copolymerization of the pressure-sensitive adhesive is from 0.1 to 0.1 with respect to the total monomer mixture.
The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape according to any one of claims 1 to 7, wherein the content is 15% by mass. 9. The method according to claim 1, wherein the amount of the (poly) alkylene glycol mono (meth) acrylate used in the copolymerization of the pressure-sensitive adhesive is 0.1 to 5% by mass based on the total monomer mixture. The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to any one of claims 1 to 8.