JP2001172579A - 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 from which a pulp is regenerated and stably recycled. SOLUTION: The pressure sensitive adhesive sheet or the pressure sensitive adhesive tape comprises a surface substrate comprising a substrate disintegrable by water or an aqueous alkali solution and a pressure sensitive adhesive layer comprising a pressure sensitive adhesive redisintegrable by water, and the pressure sensitive adhesive comprises a copolymer obtained by copolymerizing (a) 45-80 mass% of an alkyl (meth)acylate monomer bearing a 4-18C alkyl group, (b) 5-15 mass% of an ethylenically unsaturated carboxylic acid-containing monomer, (c) 1-10 mass% of methyl methacrylate and (d) 1-30 mass% of a monomer copolymerizable with (a), (b) and (c) in the presence of at least one of (poly) alkylene glycol di(meth)acrylates, (poly)alkylene glycol mono(meth)acrylates, (poly)ethylene glycols and (poly)propylene glycols and, incorporated therein, an alkanolamine equivalent to 50-120 mole % of the carboxylic groups in the copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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 or 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, vinyl ether-based emulsions, solvents and solvent-free types are used. Such an adhesive sheet or adhesive tape is a permanent adhesive type that is used for packaging products and cardboard boxes, and is permanently used after being affixed to an 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, as a raw material for the production of waste paper pulp, the amount of used waste paper including recycled waste paper is 50% of the raw material for producing paper and paperboard.
And has already occupied the position of main raw materials. Waste paper that can be recycled and pulped is newspaper, cardboard,
Magazine, imitation, color (including art), white, card, special white, medium white, white manila, ticket, Nakashiro antique, tea imitation paper (including Western steps), mount, ball, OCR paper, etc. is there. 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 affixed to cardboard as a delivery slip for home delivery, or to a returnable box such as a plastic container as a distribution management label. Recently, it is also used for stamps and other stamps.
Adhesive tapes are mainly used for packing cardboard boxes and the like. However, in the papermaking industry, they are used for temporary fixing of winding after paper making and packaging for 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.

Further, since the release sheet or the base material for the adhesive tape used for the adhesive sheet is a poor disintegrating material such as a laminated paper obtained by laminating polyethylene, it is more difficult to make the recycled pulping. It is. 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 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, pulp can be regenerated in the normal re-pulping process without contaminating the conditioned water during disintegration, and stable recycling in 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 sheet formed by laminating a surface substrate, a pressure-sensitive adhesive layer and a release sheet, wherein the surface substrate is a substrate disintegratable with water or an aqueous alkali solution. A pressure-sensitive adhesive in which the pressure-sensitive adhesive layer has a re-dispersing property with respect to water;
(Meth) acrylic acid alkyl ester monomer having an alkyl group of 8 ... 45 to 80% by mass, (b) ethylenically unsaturated carboxylic acid-containing monomer ... 5 to 15% by mass, (c) methyl methacrylate. ..1 to 10% by mass,
(D) Monomer copolymerizable with the above a, b, and c ... 1
To 30% by mass in the presence of at least one of (poly) alkylene glycol di (meth) acrylate, (poly) alkylene glycol mono (meth) acrylate, (poly) ethylene glycol, and (poly) propylene glycol. An adhesive obtained by adding an alkanolamine corresponding to 50 to 120 mol% of carboxyl groups in the copolymer to a copolymer obtained by copolymerization,
A pressure-sensitive adhesive sheet, wherein the base material of the release sheet to be used is a direct type. The present invention also provides
(2) In a pressure-sensitive adhesive tape formed by laminating a release agent layer / a base material / a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is a pressure-sensitive adhesive having a re-disintegration property with respect to water; (Meth) acrylic acid alkyl ester monomer having an alkyl group of several 4 to 18: 45 to 80% by mass, (b) ethylenically unsaturated carboxylic acid-containing monomer: 5 to 15% by mass,
(C) methyl methacrylate: 1 to 10% by mass;
(D) Monomer copolymerizable with the above a, b, and c ... 1
To 30% by mass in the presence of at least one of (poly) alkylene glycol di (meth) acrylate, (poly) alkylene glycol mono (meth) acrylate, (poly) ethylene glycol, and (poly) propylene glycol. An adhesive obtained by adding an alkanolamine corresponding to 50 to 120 mol% of carboxyl groups in the copolymer to a copolymer obtained by copolymerization,
A pressure-sensitive adhesive tape characterized in that a substrate used is a direct type.

The present invention further provides (3) a (poly) alkylene glycol di (meth) used for copolymerizing the pressure-sensitive adhesive.
The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape according to (1) or (2), wherein the addition mole number of the acrylate or the alkylene glycol of the (poly) alkylene glycol mono (meth) acrylate is 1 to 23. (4) The amount of the (poly) alkylene glycol di (meth) acryl or (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 (3), wherein (5) The pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape according to any one of (1) to (4), wherein the (poly) alkylene glycol di (meth) acrylate is polyethylene glycol dimethacrylate. (6) 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 (5), which is a mass%. (7) The pressure-sensitive adhesive sheet according to any one of (1) to (6), wherein the alkanolamine for neutralizing a carboxyl group in the copolymer has a boiling point of 100 ° C or higher. It is an adhesive tape.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape which is extremely excellent at the time of recycled pulping by using a pressure-sensitive adhesive having a particularly excellent redispersibility in water of a pressure-sensitive adhesive layer. is there. Then, in order to obtain such a recyclable pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape, a composition having a specific monomer is prepared by mixing (poly) alkylene glycol di (meth) acrylate, (poly) alkylene glycol mono (meth) acrylate, polyethylene glycol And / or using an adhesive obtained by copolymerizing in the presence of at least one of polypropylene glycol and adding an alkanolamine corresponding to 50 to 120 mol% of the carboxyl groups in the copolymer. There is a feature.

The pressure-sensitive adhesive used in the pressure-sensitive adhesive sheet and pressure-sensitive adhesive tape of the present invention comprises (a) an alkyl (meth) acrylate monomer having an alkyl group having 4 to 18 carbon atoms: 45 to 80% by mass; b) ethylenically unsaturated carboxylic acid-containing monomer: 5 to 15% by mass,
(C) methyl methacrylate: 1 to 10% by mass;
(D) Monomer copolymerizable with the above a, b, and c ... 1
To 30% by mass, in the presence of at least one of (poly) alkylene glycol di (meth) acrylate, (poly) alkylene glycol mono (meth) acrylate, (poly) ethylene glycol, and (poly) propylene glycol. Is an adhesive obtained by adding an alkanolamine corresponding to 50 to 120 mol% of the carboxyl groups in the copolymer to the copolymer obtained by copolymerization of the above.

(A) Examples of the alkyl (meth) acrylate monomer having an alkyl group having 4 to 18 carbon atoms include butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, and the like. Examples thereof include 2-ethylhexyl (meth) acrylate and stearyl (meth) acrylate. This monomer must be copolymerized to account for 45-80% by weight of the copolymer. By the way, when the amount is less than 45% by mass, the adhesive strength of the pressure-sensitive adhesive becomes poor, and when it exceeds 80% by mass, the water redispersibility becomes insufficient.

(B) Examples of the ethylenically unsaturated carboxylic acid-containing monomer include acrylic acid, methacrylic acid,
Crotonic acid, maleic acid, fumaric acid, monoalkyl maleic acid, monoalkyl itaconic acid, monoalkyl fumaric acid and the like. This monomer is 5-1 of the copolymer.
It is necessary to polymerize so as to account for 5% by mass. By the way, if it is less than 5% by mass, the water redispersibility of the pressure-sensitive adhesive becomes insufficient, and if it exceeds 15% by mass, the adhesive strength becomes insufficient,
In addition, the pressure-sensitive adhesive is likely to deteriorate with time.

(C) Methyl methacrylate must be copolymerized so as to account for 1 to 10% by mass of the copolymer. If the amount is less than 1% by mass, the water redispersibility of the pressure-sensitive adhesive is insufficient, and if it exceeds 10% by mass, the adhesive strength is insufficient.

(D) Other monomers copolymerizable with the above (a), (b) and (c) include, for example, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylate.
Cyclohexyl acrylate, glycidyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth)
Hydroxypropyl acrylate, vinyl acetate, vinyl propionate, vinyl chloride, vinylidene chloride, styrene,
Ethylene, dimethylaminoethyl (meth) acrylate,
Diethylaminoethyl (meth) acrylate, (meth) acrylonitrile, (meth) acrylamide, N-butoxymethyl (meth) acrylamide, divinylbenzene,
N, N'-methylenebis (meth) acrylamide, methoxyethyl acrylate, alkoxyalkyl (meth) acrylates such as ethoxyethyl acrylate, and the like. This monomer is 1 to 30% by mass of the copolymer.
It is necessary to copolymerize so as to occupy. If the amount is less than 1% by mass, the hydrophilicity of the pressure-sensitive adhesive will be poor, and if it exceeds 30% by mass, the adhesion will be insufficient.

Among the other copolymerizable monomers (d), hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, vinyl acetate, (meth) acrylonitrile, (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N
-Butoxymethyl (meth) acrylamide, N, N'-
When alkoxyalkyl (meth) acrylates such as methylenebis (meth) acrylamide, methoxyethyl acrylate, and ethoxyethyl acrylate are blended,
It is preferable because a copolymer having suitable hydrophilicity, water redispersibility, adhesive performance and the like can be obtained.

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

[0023]

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. Because it does not express sex
Adhesives suitable for recycling can be made. And these compounds, the hydrophilicity of the adhesive, water redispersibility,
Although it can be suitably used in consideration of the balance of adhesive performance, polyethylene glycol dimethacrylate is particularly preferable because a copolymer excellent in hydrophilicity and water redispersibility can be obtained.

The (poly) alkylene glycol di (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 pressure-sensitive adhesive is likely to aggregate during polymerization.

The (poly) alkylene glycol mono (meth) acrylate is a compound represented by the following 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.

[0027]

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 rendered 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 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. 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.

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

[0031]

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 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.

Examples of the alkanolamine include monoethanolamine, diethanolamine, triethanolamine, propanolamine, β-propanolamine, tripropanolamine, isopropanolamine, triisopropanolamine, 2-aminoisohexyl alcohol, N-methyldiethanolamine, , N-dibutylethanolamine and the like. These alkanolamines have 50 carboxyl groups in the copolymer.
It has to be added to correspond to １２０120 mol%. By the way, if it is less than 50 mol%, the adhesiveness and water redispersibility of the pressure-sensitive adhesive film will be insufficient, and if it exceeds 120 mol%, the holding power will be insufficient, and the adhesive will deteriorate and discolor over time. It will be easier.

Among these alkanolamines, in order to prevent volatilization in the drying step during the production of the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive tape and a change in quality over time, the boiling point is 100 ° C. or more, more preferably 170 ° C. It is desirable to use the above alkanolamines.

Here, the above-mentioned monomers and the (poly) alkylene glycol di (meth) acrylate, (poly) alkylene glycol mono (meth) acrylate, polyethylene glycol and / or polypropylene glycol added at the time of copolymerization to the pressure-sensitive adhesive of the present invention are used. Briefly describing the role of at least one of the alkanolamines and the alkanolamine to be added to the pressure-sensitive adhesive copolymer, components that impart water redispersibility of the pressure-sensitive adhesive include (b) an ethylenically unsaturated carboxylic acid-containing monomer and (C) Methyl methacrylate is important, and as components for imparting the tackiness of the pressure-sensitive adhesive, (a) an alkyl (meth) acrylate monomer having an alkyl group having 4 to 18 carbon atoms, and (b) ethylene The unsaturated carboxylic acid-containing monomer and (c) methyl methacrylate It is a principal. Further, as a component that imparts hydrophilicity to the pressure-sensitive adhesive and further adjusts the tackiness, (d) another monomer copolymerizable with the above (a), (b), and (c) is important. Furthermore, these pressure-sensitive adhesive composition mixtures are (poly) alkylene glycol di (meth) acrylates,
By copolymerizing in the presence of at least one of (poly) alkylene glycol mono (meth) acrylate, polyethylene glycol and / or polypropylene glycol, it is possible to impart hydrophilicity to the adhesive and simultaneously increase the molecular weight. The particles after redispersion become hard, and the particles remaining in the recycling step do not exhibit tackiness in water. In addition, in the neutralization reaction performed to develop the tackiness and water redispersibility of these copolymers, the use of an alkanolamine can prevent plasticization of the copolymer and deterioration with time of water redispersibility. . These (a),
(B), (c), (d) and at least one of (poly) alkylene glycol di (meth) acrylate, (poly) alkylene glycol mono (meth) acrylate, polyethylene glycol and / or polypropylene glycol and an alkanolamine By blending as an essential component in a well-balanced manner, the copolymer has redispersibility in water without deteriorating the adhesive force, and the redispersed particles become an adhesive having no tackiness in water. Things.

Further, a hydrophilic plasticizing substance may be added to the above-mentioned 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 sugar alcohols such as glycerin, sorbit, mannitol, dursit, idit, erythrit, arabit, and adnit.
Copolymers of polyethylene oxide or polypropylene oxide with polyhydric alcohols such as glycerin, xylitol trioxyisobutane, and sorbit; polyether polyols such as polyethylene glycol and polypropylene glycol; copolymers of ethylene oxide and propylene oxide; Ethylene alkyl ether, polyoxyethylene alkyl phenyl ether,
Nonionic surfactants such as polyoxyethylene polyoxypropylene glycol are exemplified. Considering tackiness and water redispersibility, this substance should be used in an amount of 10% by mass or less, more preferably 0.5 to 10% by mass, based on 100% by mass of the copolymer. Is desirable.

[0038] Among these hydrophilic plasticizing substances, nonionic surfactants are particularly preferable because they can finish a pressure-sensitive adhesive having good adhesiveness and storage stability.

Therefore, in order to obtain a pressure-sensitive adhesive having excellent redispersibility in water and good adhesion performance, which is used in the present invention, the above-mentioned (a) alkyl group having 4 to 18 carbon atoms is required. A (meth) acrylic acid alkyl ester monomer, (b) an ethylenically unsaturated carboxylic acid-containing monomer,
(C) Methyl methacrylate, (d) Mixing balance of other monomers copolymerizable with them, and copolymerizing them in the presence of (poly) alkylene glycol di (meth) acrylate and neutralizing with alkanolamine. Very important.

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 in 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
It is adjusted to about 0 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 method must be neutralized with an alkanolamine corresponding to 50 to 120 mol% of the carboxyl groups in the copolymer. By performing the neutralization treatment, the mechanical stability can be improved and the viscosity can be adjusted.

For neutralization of the carboxyl group in the copolymer, an alkali metal hydroxide such as potassium hydroxide or sodium hydroxide, ammonia or the like can be used in addition to alkanolamine. An alkali metal hydroxide such as potassium hydroxide is more preferably used in view of a change in adhesive performance due to volatilization over time after processing into an adhesive sheet and an adhesive tape and prevention of deterioration of water redispersibility.

The glass transition temperature of the above copolymer is -7.
It is in the range of 0 to -10 ° C and is appropriately selected depending on the purpose. Incidentally, the glass transition temperature of the copolymer is -70.
When the temperature is lower than 0 ° C, the obtained film has insufficient cohesive strength. On the contrary, when the temperature exceeds -10 ° C, the obtained film of the copolymer tends to be too hard, resulting in poor practicality.

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

Next, as the surface base material which can be disintegrated with water or an alkaline aqueous solution used for the pressure-sensitive adhesive sheet, there are fine paper, art paper, coated paper, cast paper, kraft paper, impregnated paper, low-size paper, water-soluble paper, kraft paper On paper or woodfree paper, for example, casein, dextrin, starch, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose, polyvinyl alcohol, styrene-butadiene copolymer, methylmethacrylate-butadiene copolymer, ethylene-vinyl chloride copolymer, Paper such as a base material provided with a sealing layer mainly composed of a natural or synthetic resin and / or a pigment such as an ethylene-vinyl acetate copolymer or an acrylate copolymer, polyvinyl alcohol, carboxymethyl cellulose, Water-soluble such as methylcellulose Water-soluble film formed from polymer, or copolymerization of lactic acid or lactide with glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypentanoic acid, hydroxycaproic acid, hydroxyheptanoic acid or other hydroxycarboxylic acid or polylactic acid A film formed from a lactic acid-based polymer and easily hydrolyzed with an aqueous alkali solution can be used.

Next, the direct type substrate used for the release sheet of the pressure-sensitive adhesive sheet or the substrate of the pressure-sensitive adhesive tape is a release paper substrate on which polyethylene or the like is not laminated, such as clay-coated paper, glassine paper, or the like. Kraft paper or woodfree paper, for example, casein, dextrin, 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 copolymer And a base material provided with a filler layer mainly containing a natural or synthetic resin and / or a pigment.

The paper used for the surface substrate of the pressure-sensitive adhesive sheet, the release sheet, and the substrate of the pressure-sensitive adhesive tape has a paper layer pH.
However, it is desirable to use paper having a value 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 the compound having a carboxyl group, is affected by calcium carbonate and the like contained in the coating layer of paper or coated paper. This is because the adhesive is easily deteriorated. Also,
The paper layer pH mentioned here means that the surface of the pressure-sensitive adhesive sheet or the surface opposite to the surface coated with a release agent in the case of a release sheet is swollen with an organic solvent in the case of a pressure-sensitive adhesive tape substrate. Using a cellophane tape or the like, the surface layer is peeled off to expose the base paper layer, and a commercially available test solution (for example, a pH meter for paper surface measurement, manufactured by Kyoritsu Riken Co., Ltd.) that discolors due to pH is applied to the paper surface. And colorimetrically compared to a standard color.

The sealing layer mainly composed of a resin and / or a pigment used in a direct type substrate used as a release sheet of an adhesive sheet or a substrate of an adhesive tape is not particularly limited. Casein, dextrin, starch, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose, polyvinyl alcohol, styrene-
Natural or synthetic resin such as butadiene copolymer, methyl methacrylate-butadiene copolymer, ethylene-vinyl chloride copolymer, acrylate ester copolymer and / or kaolin, calcium carbonate, clay, talc, calcined kaolin, delamikaolin And inorganic pigments such as titanium dioxide, aluminum hydroxide, silica, and white carbon; or organic synthetic pigments such as polystyrene resin fine particles, urea-formalin resin fine particles, and fine hollow particles.

In addition to the base material provided with the filler layer, a base material provided with a printing coating layer containing a pigment as a main component on the surface of paper, such as art paper, coated paper, cast coated paper, etc. A material may be used. Of course, a pre-printed substrate can be applied if necessary.

When the pigment coating layer is provided,
An adhesive is used in the pigment coating liquid in order to fix the pigments and the pigment and the surface of the substrate in addition to the pigment. Such adhesives include, for example, casein, dextrin, 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 copolymer Natural or synthetic adhesives are used in the form of aqueous solutions or dispersions (emulsions). In addition, in addition to these pigments and adhesives, various auxiliaries such as antifoaming agents, dispersants, preservatives, and dyes are added to the pigment coating liquid as needed, as long as the properties are not impaired. You can also.

The coating liquid for the filling layer containing such a resin and / or a pigment as a main component can be used in a general coating such as a blade coater, a bar coater, an air knife coater, a gravure coater, a roll coater, a die coater, and a lip coater. Coated on the device to be coated. The coating amount in this case is
2 g / m ² or more, preferably 4 to 30 g /
It is adjusted in the range of m ^2.

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

In recent years, a tape-shaped one without release paper has been developed as one form of an adhesive label from the viewpoint of resource saving. In this case, printing of printing paper such as art paper or coated paper is performed. It is a product that has a release printing layer on the surface,
Such a layer may be used instead of the release agent layer.

In the method of forming the pressure-sensitive adhesive sheet, the 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 the 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 for 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 a pressure-sensitive adhesive sheet or 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 adhesive varies depending on the purpose, but is 3 g / m ^2.
As described above, it is more preferably adjusted in the range of about 5 to 50 g / m ² . Incidentally, it is less than 3 g / m ^2, the adhesion performance of the adhesive sheet or pressure-sensitive adhesive tape obtained becomes insufficient, whereas adhesive or sticking during the production of the adhesive sheet or an adhesive tape exceeds 50 g / m ^2, at the time of peeling It may cause cohesive failure.

[0060]

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 indicated by solid content or mass of active ingredient.

Example 1 (Preparation of adhesive) First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 250 parts Acrylic acid: 35 parts Methyl (meth) acrylate: 20 parts Methoxyethyl acrylate: 75 parts Acetic acid Vinyl: 20 parts Anionic emulsifier (trade name: Emar NC-35 / Kao Corporation): 6 parts Ion-exchanged water: 150 parts mixed, excluding emulsifier and ion-exchanged water (the same applies hereinafter) for all monomer mixtures It was prepared by adding 0.9% by mass of polyethylene glycol dimethacrylate (trade name: NK ester A-4G / manufactured by Shin-Nakamura Chemical Co., Ltd.).

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 mol% of the carboxyl group in the copolymer was added with triethanolamine to carry out a neutralization reaction, and after completion of the reaction, 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.

[0065] (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 (Production of adhesive) First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 330 parts Acrylic acid: 60 parts Methyl (meth) acrylate: 5 parts Vinyl acetate: 5 Anionic emulsifier ( Trade name: Emal NC-35 / Kao Corporation): 6 parts Ion exchange water: 150 parts were mixed, and polyethylene glycol dimethacrylate (trade name: NK ester 9G /
It was prepared by adding 1.8% by mass of Shin Nakamura Chemical Co., Ltd. and 2.7% by mass of polypropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd./average molecular weight: 1000). Next, a copolymer was prepared in the same manner as in Example 1, and a neutralization reaction was performed by adding triethanolamine and a 10% aqueous potassium hydroxide solution each to 50 mol% of the carboxyl groups in the copolymer.
Further, 4 parts of a nonionic surfactant (trade name: Emulgen 810 / 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.

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 3 (Production of adhesive) First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 250 parts Acrylic acid: 25 parts Methyl (meth) acrylate: 40 parts Methoxyethyl acrylate: 75 parts Acetic acid Vinyl: 10 parts Anionic emulsifier (trade name: Emar NC-35 / Kao Corporation): 6 parts Deionized water: 150 parts were mixed, and polyethylene glycol dimethacrylate (trade name: NK ester 9G) was mixed with all monomer mixtures. /
It was prepared by adding 2.7% by mass of Shin-Nakamura Chemical Co., Ltd. and 4.0% by mass of polypropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd./average molecular weight: 1000). Next, a pressure-sensitive adhesive was produced in the same manner as in Example 2.

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 4 (Production of adhesive) First, 2-ethylhexyl acrylate: 190 parts Acrylic acid: 35 parts Methyl (meth) acrylate: 20 parts Methoxyethyl acrylate: 90 parts Acetic acid Vinyl: 25 parts Anionic emulsifier (trade name: Emar NC-35 / Kao Corporation): 6 parts Deionized water: 150 parts were mixed, and polyethylene glycol monomethacrylate (trade name: Blemmer PE-) was mixed with all monomer mixtures.
200 / Nippon Yushi Co., Ltd.) in an amount of 2.7% by mass. Next, a copolymer was produced in the same manner as in Example 1, and a neutralization reaction was carried out by adding 100 mol% of carboxyl groups in the copolymer to triethanolamine. further,
To 100 parts of this adhesive, 4 parts of a nonionic surfactant (trade name: Emulgen 810, manufactured by Kao Corporation) was 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 5 (Production of pressure-sensitive adhesive)
A pressure-sensitive adhesive was prepared in the same manner as in Example 1 except that 0.9% by mass of polyethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd./average molecular weight: 1000) was added to a mixed solution having the same monomer composition as in Example 1. Manufactured.

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: 290 parts Acrylic acid: 35 parts Methyl (meth) acrylate: 20 parts Methoxyethyl acrylate: 35 parts Acetic acid Vinyl: 20 parts Anionic emulsifier (trade name: Emar NC-35 / Kao Corporation): 6 parts Deionized water: 150 parts were mixed, and polyethylene glycol dimethacrylate (trade name: NK ester 9G) was added to all monomer mixtures. /
It was prepared by adding 1.8% by mass of Shin-Nakamura Chemical Co., Ltd. and 4.0% by mass of polypropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd./average molecular weight: 1000). Next, a pressure-sensitive adhesive was produced in the same manner as in Example 2.

(Preparation of Surface Substrate and Adhesive Tape Substrate) 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-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 1 using the above pressure-sensitive adhesive and surface substrate
In the same manner as in the above, an adhesive sheet was produced.

A pressure-sensitive adhesive tape was prepared in the same manner as in Example 1 using the above-mentioned pressure-sensitive adhesive and tape base material.

Example 7 A pressure-sensitive adhesive sheet and a pressure-sensitive adhesive tape were prepared in the same manner as in Example 6, except that the following substrates were used as the surface substrate and the substrate for the pressure-sensitive adhesive tape.

(Preparation of Surface Substrate and Adhesive Tape Substrate) 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.

Comparative Example 1 (Production of adhesive) First, as an emulsified monomer mixture, 2-ethylhexyl acrylate: 250 parts Acrylic acid: 35 parts Methyl (meth) acrylate: 20 parts Methoxyethyl acrylate: 75 parts Acetic acid Vinyl: 20 Anionic emulsifier (trade name: Emar NC-35 / manufactured by Kao Corporation): 6 parts Ion-exchanged water: 150 parts was mixed and prepared.

Next, a copolymer was produced in the same manner as in Example 1, and 50% by mole of carboxyl groups in the copolymer were added to carry out a neutralization reaction to obtain a pressure-sensitive adhesive.

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 adhesive) As an emulsified monomer mixture, 2-ethylhexyl acrylate: 260 parts Acrylic acid: 15 parts Methyl (meth) acrylate: 30 parts Methoxyethyl acrylate: 75 parts Vinyl acetate : 20 parts Anionic emulsifier (trade name: Emar NC-35 / Kao Corporation): 6 parts Deionized water: 150 parts were mixed, and polyethylene glycol dimethacrylate (trade name: NK ester 9G /
It was prepared by adding 1.8% by mass of Shin Nakamura Chemical Co., Ltd. and 2.7% by mass of polypropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd./average molecular weight: 1000). Next, a pressure-sensitive adhesive was produced in the same manner as in Example 2.

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 adhesive) As an emulsified monomer mixture, 2-ethylhexyl acrylate: 345 parts Acrylic acid: 50 parts Methyl (meth) acrylate: 5 parts Anionic emulsifier (trade name: Emar NC) -35 / Kao Corporation): 6 parts Ion-exchanged water: 150 parts were mixed, and polyethylene glycol dimethacrylate (trade name: NK ester 9G /
It was prepared by adding 2.7% by mass of Shin-Nakamura Chemical Co., Ltd. and 4.0% by mass of polypropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd./average molecular weight: 1000). Next, a pressure-sensitive adhesive was produced in the same manner as in Example 4.

An adhesive sheet was prepared in the same manner as in Example 1 except that the above-mentioned 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: 195 parts Acrylic acid: 25 parts Methyl (meth) acrylate: 45 parts Methoxyethyl acrylate: 115 parts Vinyl acetate : 20 parts 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-) was mixed with all monomer mixtures.
200 / Nippon Yushi Co., Ltd.) in an amount of 2.7% by mass. Next, a pressure-sensitive adhesive was produced in the same manner as in Example 4.

An adhesive sheet was prepared in the same manner as in Example 1 except that the above-mentioned 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 Pressure-Sensitive Adhesive)
Against a mixture of the same monomer composition as polyethylene glycol dimethacrylate (trade name: NK Ester 9G)
(Manufactured by Shin-Nakamura Chemical Co., Ltd.) in an amount of 0.9% by mass. Next, a copolymer was produced in the same manner as in Example 1, a neutralization reaction was performed with aqueous ammonia, and after the reaction was completed, 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.

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

Comparative Example 6 (Production of PSA) An emulsified monomer mixture was prepared in the same manner as in Comparative Example 5, then a copolymer was produced in the same manner as in Example 1, and triethanolamine was added to the copolymer. Was neutralized by adding 150 mol% of the carboxyl groups of the above, and after the reaction was completed, 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.

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 7 As a pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive insoluble in water and an aqueous alkaline solution (trade name: Nicazole L-145 / manufactured by Nippon Carbide Industrial Co., Ltd.) was coated so as to have a dry mass of 22 g / m ^2. A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 7, except for drying.

Comparative Example 8 A commercially available polyethylene laminated kraft paper pressure-sensitive adhesive tape (trade name: OJI kraft tape / Oji Chemical Co., Ltd.) was used as a pressure-sensitive adhesive tape to prepare a sample for evaluation.

Comparative Example 9 A pressure-sensitive adhesive sheet and a pressure-sensitive adhesive tape were prepared in the same manner as in Example 6, except that a commercially available polyethylene laminated paper was used as a release paper substrate and a pressure-sensitive adhesive tape substrate.

Comparative Example 10 An adhesive sheet was prepared in the same manner as in Example 1 except that a commercially available polyethylene terephthalate film (manufactured by Toyobo Co., Ltd.) was used as the surface substrate.

Comparative Example 11 (Production of Pressure-Sensitive Adhesive) 2-Ethylhexyl acrylate: 310 parts Acrylic acid: 65 parts Methyl (meth) acrylate: 5 parts Vinyl acetate 20 Anionic emulsifier (trade name) : Emal NC-35 / Kao Corporation): 6 parts Ion-exchanged water: 150 parts were mixed, and polyethylene glycol dimethacrylate (trade name: NK ester 9G /
It was prepared by adding 1.8% by mass of Shin Nakamura Chemical Co., Ltd. and 2.7% by mass of polypropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd./average molecular weight: 1000). Next, a copolymer was prepared in the same manner as in Example 2, and a neutralization reaction was performed by adding 50 mol% of the carboxyl groups in the copolymer with triethanolamine and a 10% aqueous potassium hydroxide solution, respectively, to complete the reaction. Thereafter, 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 produced in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive was used.

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

(Evaluation Test Items) [Adhesion] JIS-Z-
According to the measuring method of normal adhesive strength of No. 0237, the adhesive strength after storage under the following two conditions was measured. (Unit: N / m) Condition A: After the production of the pressure-sensitive adhesive sheet and the pressure-sensitive adhesive tape, temperature 2
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.

[Cohesive force] The cohesive force was measured by a method in accordance with the method for measuring a normal holding power according to JIS-Z-0237, and evaluated according to the following evaluation criteria. After the production of adhesive sheet and adhesive tape,
After storing for 7 days in an atmosphere at a temperature of 23 ± 2 ° C. and a relative humidity of 65 ± 5%, the adhesive strength was measured. ：: The load weight dropped after 5 minutes. X: The load weight dropped during less than 5 minutes.

[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.

[Adhesive Water Redispersibility] The adhesive behavior when the adhesive layer surface of the adhesive sheet was rubbed 10 times with a finger while immersed in water at 20 ° C. was evaluated according to the following evaluation criteria. ：: The pressure-sensitive adhesive layer was redispersed into fine particles having no tackiness. Δ: The adhesiveness of the adhesive layer is reduced, but the adhesive layer is not finely dispersed or aggregated. X: The adhesiveness of the adhesive layer was not changed, and the adhesive layer film was aggregated.

[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 7 and Comparative Examples 1 to
Adhesive sheets of Comparative Examples 8, 10, and 11: Assuming a label for addressing that is used by being attached to an envelope, a release sheet is peeled off from the adhesive sheet to form an adhesive label, and a commercially available rice tsubo 64 g / m ^2. The paper was affixed to high-quality paper to obtain an evaluation paper fee. Similarly, assuming that the adhesive tape is used by attaching to a packaging material capable of recycling used paper, the 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. Adhesive sheets of Examples 1 to 7 and Comparative examples 1 to 11: The adhesive sheets themselves were used as evaluation samples, 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 prepare a TAPPI standard disintegrator (JIS-JIS).
The device described in Annex A of P-8220) (3000
rpm), the pulp concentration becomes 15%
The mixture was dehydrated with a 60-mesh nylon screen until 1.5 g of an 18% NaOH aqueous solution and 1.8 g of a 10% deinking agent (trade name: DI-600 / Kao Corporation) were added. The mixture was allowed to stand at 40 ° C. for 20 minutes, then dehydrated with a 60-mesh nylon screen until the pulp concentration became 25%, and 3.85 g of a 30% aqueous NaSiO ₃ solution and 5 g of a 6% aqueous H ₂ O ₂ solution. Each addition was performed, and then a kneading treatment was performed for 5 minutes using a double-armed kneader. Then, after stirring at 55 ° C. for 120 minutes,
The mixture was diluted with water until the pulp concentration reached 17.5%, and 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, the pulp dispersion having a concentration of 1% was floated and separated by a flotator for 10 minutes, bubbles generated at that time were removed by a scraper, dewatered again by a 60-mesh nylon screen, and washed with 1000 ml of water. It was dehydrated to a concentration of 13%. Water was added to the pulp dispersion liquid thus obtained to a concentration of 0.3% to prepare a hand-made sheet, and the remaining state of undisintegrated material was visually observed and judged according to the following evaluation criteria.

(Criteria for Recycling Suitability Evaluation) A: Almost no undisintegrated material. ：: There is a little undisintegrated matter, but there is no practical problem. Δ: The undisintegrated substance is considerably conspicuous. X: There is an undisintegrated substance, and the undisintegrated substance is sticky.

[Overall Evaluation] The above evaluations were combined to evaluate the performance as a recyclable pressure-sensitive adhesive sheet and pressure-sensitive adhesive tape of the present invention. ：: In an adhesive sheet or an adhesive tape having an adhesive layer formed on one surface of a base material, it is possible to recycle waste paper as it is or as it is attached to a packaging material, and the adhesive performance of the adhesive In the above, the adhesive strength is less deteriorated by heat and humidity, and the cohesive strength is excellent. ：: In an adhesive sheet or an adhesive tape in which an adhesive layer is formed on one surface of a base material, it is possible to recycle waste paper as it is or as it is attached to a packaging material, and the adhesive performance of the adhesive In this case, the cohesive strength is excellent, but the adhesive strength is slightly degraded by heat and humidity, but the level is not a problem. △: Recycling of used paper is possible as it is with the adhesive sheet or attached to the packaging material, but the adhesive performance is poor, such as the cohesive strength of the adhesive is insufficient or the adhesive strength is significantly deteriorated by heat and humidity. There is a problem. ×: Regardless of the adhesive performance, the pressure-sensitive adhesive sheet remains
Or, it is impossible to recycle waste paper with it attached to the packaging material.

[0124]

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

[0125]

[Table 2]

[0126]

As shown in Tables 1 and 2, the pressure-sensitive adhesive sheet and the pressure-sensitive adhesive tape of the present invention are excellent in recyclability as waste paper pulp because the pressure-sensitive adhesive is easily redispersed in water, and are necessary at the time of sticking. The adhesive sheet and the adhesive tape exhibited an excellent adhesive strength, and were easily removed outside the process even if the adhesive sheet was adhered to the packaging material or the adhesive sheet or mixed in the recycling process.

Claims (6)

[Claims] A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer provided on a surface substrate and a pressure-sensitive adhesive layer and a release sheet laminated in a releasable manner or a pressure-sensitive adhesive tape comprising a release agent layer / substrate / pressure-sensitive adhesive layer laminated. , The surface base material is a base material that can be disintegrated with water or an aqueous alkali solution, the base material of the release sheet or the base material of the pressure-sensitive adhesive tape to be used is a direct type, and the pressure-sensitive adhesive layer has re-disintegration properties with respect to water. An adhesive, wherein the adhesive is
(A) an alkyl (meth) acrylate monomer having an alkyl group having 4 to 18 carbon atoms: 45 to 80% by mass; (b) an ethylenically unsaturated carboxylic acid-containing monomer: 5 to 15% by mass; (C) Methyl methacrylate
1 to 10% by mass, (d) a monomer copolymerizable with the above a, b, c ... 1 to 30% by mass is defined as (poly) alkylene glycol di (meth) acrylate, (poly) alkylene glycol mono. (Meth) acrylate, (poly)
For a copolymer obtained by copolymerization in the presence of at least one of ethylene glycol and (poly) propylene glycol, 50 to 1 of a carboxyl group in the copolymer is used.
An adhesive sheet or an adhesive tape, which is an adhesive obtained by adding alkanolamine corresponding to 20 mol%. 2. 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 added alkylene glycol. The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to claim 1, wherein 3. A (poly) alkylene glycol di (meth)
The acrylate or the (poly) alkylene glycol mono (meth) acrylate is added in an amount of 0.1 to 5% by mass based on the entire monomer mixture. Adhesive sheet or tape. 4. A (poly) alkylene glycol di (meth)
The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the acrylate is polyethylene glycol dimethacrylate. 5. The amount of (poly) ethylene glycol and / or (poly) propylene glycol used during copolymerization of the pressure-sensitive adhesive is 0.1 to 0.1% 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 4, wherein the pressure-sensitive adhesive sheet or the pressure-sensitive adhesive sheet has a content of about 15% by mass. 6. The pressure-sensitive adhesive sheet according to claim 1, wherein the alkanolamine for neutralizing a carboxyl group in the copolymer has a boiling point of 100 ° C. or higher. Adhesive tape.