JP2888083B2 - Adhesive sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive sheet, and more particularly to a pressure-sensitive adhesive sheet which is excellent in ink jet recording suitability and improved in writing suitability and label suitability.

[0002]

2. Description of the Related Art Adhesive sheets have been used in a wide variety of applications such as labels, seals, stickers, patches and the like for commercial, office and home use. A general configuration of the pressure-sensitive adhesive sheet is formed by laminating a surface substrate, a pressure-sensitive adhesive, and a release sheet . Paper, film, metal foil, etc. are used for the surface substrate, and release agents such as silicone compounds and fluorine compounds are applied to high density base paper such as glassine paper, clay coated paper, polyethylene laminate base paper, etc. as release sheets. The engineered one is used. As the pressure-sensitive adhesive, various pressure-sensitive adhesives such as an emulsion type such as a rubber type, an acrylic type and a vinyl ether type, a solvent type and a non-solvent type are used.

[0003] The adhesive sheet is subjected to slitter cutting, guillotine cutting, die cutting, etc. according to the intended use. At that stage, the adhesive adheres to the slitter cutting blade, guillotine cutting blade, die cutting blade, etc. Is the problem. The adhesion of the pressure-sensitive adhesive lowers the work efficiency during cutting. Further, if the adhesive adhered to the blade is transferred to the sheet, smooth feeding cannot be performed at the time of printing on the sheet or at the time of attaching the label, which causes a great decrease in work efficiency.

On the other hand, the use of ink jet printers for printing and recording on such adhesive sheets is increasing. 2. Description of the Related Art Ink jet printers have advantages such as low noise, high-speed recording, and easy multi-color printing with the rise of computers in the information society in recent years.

Conventionally, efforts have been made to improve recording devices and ink compositions so that general-purpose commercially available paper such as high-quality paper and coated paper can be used as a surface base material of an adhesive sheet for an ink jet printer. The fact is that no product has been obtained. Further, with the improvement of the performance of a printing apparatus such as higher-speed printing and higher definition of printing, and the expansion of applications such as full-color printing, higher properties are required for the surface base material.

[0006] The quality of the surface substrate of the pressure-sensitive adhesive sheet for an ink jet printer is, specifically, that the ink is rapidly absorbed, no bleeding or stain is generated, and that the diffusion of ink dots in the horizontal direction is not unnecessarily large and uniform. There is,
It is required that the density of the ink dots is high and clear, and that the recorded image does not undergo discoloration or fading due to the influence of light or oxygen in the air during storage.

Several proposals have hitherto been made for these quality requirements. For example, an attempt to provide an ink receiving layer mainly composed of a pigment having good ink absorbency and a binder on a base material has been attempted since the beginning of the development of inkjet recording paper. As pigments for the ink receiving layer, silica pigments are disclosed in JP-A-52-9074, JP-A-55-51583, and JP-A-56-1485.
No. 83, No. 58-72495, etc., which have been commonly used. JP-A-55-144172 and JP-A-55-146786, which use a water-soluble polymer coating layer as an ink receiving layer, have also been proposed.

[0008] However, in the former case of pigment coating, since a pigment coating layer is provided, paper dust is generated due to poor printability and writability. In the case of the latter water-soluble polymer coating layer, the aim is to achieve effects such as high-density recording and ink drying properties. Therefore, there is a drawback that bleeding of the ink occurs when writing is performed with a water-based pen or the like, and no ink that satisfies both the ink jet aptitude and the water-based pen writing property has been obtained.

[0009]

DISCLOSURE OF THE INVENTION The present invention provides an ink jet printer which has excellent ink receptivity, can obtain a clear and clear outline of a recorded image, is excellent in storability and writability of the recorded image, and Provided is a pressure-sensitive adhesive sheet that has improved label detachment and pressure-sensitive adhesive protrusion in processing such as cut printing of the pressure-sensitive adhesive sheet.

[0010]

SUMMARY OF THE INVENTION The present invention provides a pressure-sensitive adhesive sheet comprising a surface substrate, a pressure-sensitive adhesive, a release agent, a primer, and a release substrate.
The base material is a base paper, a cationic synthetic resin, and a cationic surface sizing agent in an amount of 0.003 to 0.2% by weight (based on the total solid content).
In a pressure-sensitive adhesive sheet comprising a coating agent containing: (a) a basecoat agent having at least one kind of (meth) acrylic acid ester having a hydroxyl group in a molecule as a main component and at least one kind of another vinyl monomer copolymerizable therewith; And a copolymer obtained by emulsion copolymerization of
An adhesive sheet comprising 50 to 150 parts by weight of a pigment.

[0011]

The cationic synthetic resin used as a main component in the coating agent applied to the base paper of the surface substrate in the present invention includes:
For example, synthetic resins such as a polyamide epichlorohydrin resin, a melamine formaldehyde resin, and a polyamide resin can be exemplified. These resins are prepared in an aqueous coating solution and applied.

As the water-soluble polymer, synthetic polymers such as polyvinyl alcohol and cationic polyvinyl alcohol, starches such as oxidized starch and cationized starch, and cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose can be used. May be used together within a range that does not impair.

Examples of the cationic surface sizing agent to be contained as an auxiliary agent in the above-mentioned aqueous coating solution include, for example, styrene, styrene acrylic, amide and the like. The amount of addition is 0.
003 to 0.2% by weight, more preferably 0.005 to 0.15% by weight
It is important to use within the range. If the amount is less than 0.003% by weight, the suitability for writing with an aqueous pen is poor. On the other hand, 0.2% by weight
If the addition exceeds 3, the drying property of the ink-jet ink is reduced.

In the present invention, a cationic synthetic resin is used as a synthetic resin as a main component, and a cationic surface sizing agent is used in combination with an auxiliary agent. Aqueous pen writing suitability can be improved.

[0015] The above-mentioned coating liquid is used in a two-roll or metering blade type size press, gravure coat,
Coating is performed by a coating device such as a gate roll, a bill blade, and a short dwell coater. The coating amount is preferably about 0.5 to 3.0 g / m ^{2 on} both sides. If necessary, smoothing is performed by a device such as a calender or a super calender.

The base paper of the surface substrate is made of chemical pulp such as softwood or hardwood such as KP, SP, and AP, as well as SCP, BCTMP, CTMP, and CG.
Mechanical pulp such as P, RGP, SGP, TMP,
Used paper pulp such as DIP is a main component, and if necessary, non-wood pulp such as hemp pulp, synthetic pulp, various synthetic fibers and glass fibers are appropriately combined.

The fillers for the papermaking raw materials include mineral fillers such as talc, kaolin, clay, calcined kaolin, calcium carbonate, aluminum hydroxide, titanium dioxide, magnesium silicate, magnesium sulfate, aluminosilicate, silica, bentonite, and polystyrene. Resin fine particles, urea formalin resin fine particles, thermally expandable fine hollow particles, non-thermally expandable fine hollow particles, and other organic fillers are used.

Further, as papermaking additives, sizing agents such as anionic, cationic rosin-based sizes, petroleum-based sizes, alkylketene dimer-based sizes, alkenyl succinic anhydride-sized and stearic anhydride-based sizes, and anionic and cationic , Nonionic or amphoteric polyacrylamide polymer, polyethyleneimine and derivatives thereof,
Polyamide, polyamine and derivatives thereof, polyethylene oxide, vegetable gum, polyvinyl alcohol, cationic latex, cationic urea formalin resin, melamine formalin resin, retention improver for organic compounds such as polyamide resin, drainage improver, paper strength Enhancers are used, dyes, pH adjusters, pitch control agents,
A slime control agent, an antifoaming agent and the like can be appropriately selected and used as needed.

The above papermaking raw materials are acidified or neutralized by a long net paper machine, a twin wire paper machine, a short net paper machine, a round net paper machine, a Yankee paper machine or the like.

In order to obtain a surface substrate having excellent suitability for ink jet recording according to the present invention, the initial penetration rate of a 50% by weight aqueous solution of diethylene glycol was 3.5 g as a base paper for the surface substrate.
It is preferable to use a base paper of at least / sec. If the initial permeation rate is less than 3.5 g / sec, even if the coating liquid is applied to the base paper, most of the coating liquid components will remain in the paper surface layer, and the absorptivity of the inkjet ink will decrease. Tend to.

The initial permeation rate referred to here is a value expressing the initial permeation amount of a specific aqueous solution into a recording paper using a dynamic wettability tester (WET-3000 / manufactured by Resca Corporation). It is. Specifically, using the above tester, width 2 cm ×
A test piece having a length of 5 cm is immersed in the liquid to a depth of 12 mm in the length direction, and the immersion time (second) and the permeation amount (g) of the aqueous solution are measured. The immersion is performed until the amount of permeation becomes substantially equilibrium.

The measured immersion time (second) and the permeation amount (g) of the aqueous solution are shown, and a tangent line is drawn from the curve to 0 second to obtain the permeation amount in the equilibrium state and the immersion time at that time. And
The equilibrium penetration is divided by the immersion time to give the initial penetration rate g / sec. Further, with reference to the drawings, when the sample is immersed in the liquid to a depth of 12 mm, the sample passes through the point C. This C
The value of the point is used as a reference for the amount of penetration, and the curve (C, D,
E, F, and G) are movements of the amount of permeation. The straight line portion from the point C is extended (X), the intersection with the permeation amount value in the equilibrium state is defined as the point Z, and a perpendicular line is drawn from the point Z to the reference value, and ZY (g) / CY ( Second) is quantified as the specific initial penetration rate.

For example, even if the amount of permeation after a certain period of time is the same, the value of the initial permeation speed differs depending on the type of paper. By measuring the initial penetration rate, the initial penetration state of the recording paper can be known very sharply, and the suitability for ink jet printing and the suitability for writing with a water pen can be evaluated together.

It was also found that among various aqueous solutions, the initial permeation rate using a 50% by weight aqueous solution of diethylene glycol shows an extremely high correlation.

To control the initial penetration rate of the base paper, the pulp composition, beating conditions, filler, paper strength agent, internal sizing agent,
The control of the operating conditions according to the paper machine, such as the control of the blending of the pH adjuster and the like, the drying conditions, the pressurizing conditions, and the like, can be appropriately selected and performed.

In the present invention, a cationic synthetic resin is used as a main component and a cationic surface sizing agent is used as an auxiliary in an amount of 0.004.
The surface substrate obtained by applying a coating agent solution containing 3 to 0.2% by weight has an initial penetration rate of 50% by weight ethylene glycol aqueous solution of 3.0 to 7.0 g / sec, more preferably 3.5 to 6.5 g.
/ S range. When the initial penetration rate of the surface substrate is less than 3.0 g / sec, the aqueous pen writing suitability is good, but even when the ink jet recording density is high, the ink absorption after recording is remarkably slow, and the rubbing stain on the recording portion is reduced. Tend to occur. On the other hand, if it exceeds 7.0 g / sec, the ink absorption after ink jet recording is fast, but the recording density is low, and bleeding by water-based pen writing tends to occur.

The release sheet constituting the pressure-sensitive adhesive sheet of the present invention is obtained by providing a release base on a release substrate and applying a release agent. The primer has at least one kind of (meth) acrylate having a hydroxyl group in a molecule,
A copolymer (emulsion) obtained by emulsion-copolymerizing this with at least one other copolymerizable vinyl monomer.
) To which a specific amount of pigment is added.

[0028] the specific copolyarylene used in the present invention
Examples of the (meth) acrylic acid ester having a hydroxyl group in the molecule constituting the rimer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and polyethylene glycol monoester. Examples include (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, and glycerol mono (meth) acrylate, and at least one of these can be used.

These (meth) acrylic acid esters having a hydroxyl group remarkably improve the adhesion to the silicone resin, and the amount of the (meth) acrylic acid ester is preferably 0.5% by weight or more based on the total amount of the monomers. In particular, when the content is about 3 to 20% by weight, the adhesion to the silicone resin is remarkably improved, so that it can be applied to both high-temperature crosslinking type and low-temperature crosslinking type silicone resins. However, if the amount of the (meth) acrylic acid ester having a hydroxyl group is 30% by weight or more, the stability of the obtained emulsion is undesirably reduced.

Other vinyl monomers copolymerizable with the (meth) acrylic ester having a hydroxyl group include, for example, (meth) acrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, monoalkyl maleic acid ,
Ethylenically unsaturated carboxylic acid-containing monomers such as monoalkyl fumaric acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate,
Octyl (meth) acrylate, (meth) acrylic acid-2
-Ethylhexyl, lauryl (meth) acrylate, stearyl (meth) acrylate, vinyl acetate, vinyl chloride,
Vinylidene chloride, (meth) acrylonitrile, styrene, ethylene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate,
Triethylene glycol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, 1,3-
Butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, divinylbenzene, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) ) Acrylate, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N,
N'-methylenebis (meth) acrylamide and the like can be mentioned, and one or more of these can be used in combination.

The proportion of these other copolymerizable monomers in the copolymer is adjusted in the range from 70 to 99.5% by weight.

In the release sheet of the present invention, 3 to 15% by weight of the above-mentioned (meth) acrylic acid ester having a hydroxyl group, 2 to 20% by weight of an ethylenically unsaturated carboxylic acid, and C4 to
(Meth) acrylic acid ester having C10 alkyl group
Copolymer obtained by copolymerizing 40 to 80% by weight of another monomer such as (meth) acrylonitrile 2 to 40% by weight
(Emulsion) is preferably used.

In the present invention, melamine, epoxy, isocyanate and aziridine compounds may be used as a crosslinking agent, if necessary.

The above emulsion can be obtained by usual emulsion polymerization. This polymerization reaction is carried out in an aqueous medium, and the emulsifier is contained in the range of 2 to 6% by weight based on the total amount of the monomers. When the amount of the emulsifier used is less than 2% by weight, the stability of the obtained emulsion becomes insufficient and the particle size of the polymer becomes large. On the other hand, if it exceeds 6% by weight, the adhesion between the undercoat layer and the release agent layer is reduced.

As emulsifiers, potassium oleate, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium alkylnaphthalenesulfonate,
Sodium dialkyl sulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl allyl ether sulfate, ammonium polyoxyethylene dialkyl sulfate, ammonium polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl allyl Nonionics such as anionic surfactants such as ether phosphates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, poly (oxyethylene-oxypropylene) block copolymers, polyethylene glycol fatty acid esters, and polyoxyethylene sorbitan fatty acid esters A system surfactant can be exemplified. Further, as a low molecular weight polymer compound having an emulsifying and dispersing ability, for example, polyvinyl alcohol and a modified product thereof, polyacrylamide, a polyethylene glycol derivative, a neutralized product of a polycarboxylic acid copolymer, casein, etc., alone or in combination with the above emulsifier Can be used.

The monomer concentration during the polymerization is suitably about 30 to 70% by weight, more preferably about 40 to 60% by weight. Examples of the polymerization initiator used in the polymerization include persulfates such as ammonium persulfate, 2,2'-azobisisobutyronitrile, and 2,2'-azobis (2,4-
So-called redox comprising azo compounds such as dimethylvaleronitrile), peroxides such as hydrogen peroxide, benzoyl peroxide and lauroyl peroxide, ammonium persulfate or a combination thereof with a reducing agent such as sodium sulfite or sodium acid sulfite. And the like. The amount of the polymerization initiator used is about 0.2 to 2% by weight, preferably 0.3 to 2% by weight, based on the total amount of the monomers to be subjected to polymerization.
It is desirable to use about 1% by weight. The polymerization reaction is usually 60 ~
It is performed at about 100 ° C for about 2 to 8 hours.

In the present invention, the glass transition temperature of the copolymer contained in the emulsion thus obtained is also important, and a copolymer having a glass transition temperature of -30 to + 20 ° C, more preferably -20 to + 10 ° C is selected. Is used regularly. When the glass transition temperature is lowered below −30 ° C., the tackiness of the film becomes too strong.
The resulting film becomes too hard and loses practicality.

The glass transition temperature Tg of the copolymer is:
In the present invention, it is estimated based on the following general formula (1).

[0039]

(Equation 1)

It is necessary that the undercoat layer of the present invention contains a specific amount of pigment. By providing the undercoat layer containing pigment, the blocking of the undercoat layer is controlled, and the coating at the time of coating is performed. Stability is also improved. As the pigment to be contained in the undercoat agent layer, ordinary inorganic or organic pigments can be used, and specifically, for example, oxides of various metals such as magnesium, calcium, zinc, barium, titanium, aluminum, antimony, and lead, water Examples include oxides, sulfides, carbonates, sulfates, or silicate compounds, and fine solid polymer powders such as polystyrene, polyethylene, and polyvinyl chloride. Above all, if an inorganic pigment such as kaolin, talc, silica, gypsum, barite powder, alumina white, gloss white, satin white, titanium oxide, or calcium carbonate is used, blocking can be efficiently prevented.

The amount of the pigment contained in the undercoat layer is adjusted in the range of 50 to 150 parts by weight of the pigment based on 100 parts by weight of the copolymer . If the amount is less than 50 parts by weight, the adhesiveness of the film becomes too strong, and if it exceeds 150 parts by weight, the solvent barrier property of the film becomes insufficient, so that an appropriate peeling performance cannot be obtained.

In the undercoat coating liquid of the present invention, for example, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose,
Various water-soluble natural polymers such as cellulose derivatives such as carboxymethyl cellulose, dextrin, acid-treated starch, oxidized starch, cross-linked starch, starch ester, and graft copolymer starch; ethylene glycol, glycerin, trimethylolpropane, diethylene glycol Water-soluble plasticizers such as polyhydric alcohols such as polyalkylene glycols such as polyethylene glycol and polypropylene glycol; urea / formaldehyde resin, melamine / formaldehyde resin, polyamide / polyamine / epichlorohydrin resin, polyacrylamide resin;
Crosslinking agents such as epoxy resins; furthermore, inorganic salts; fillers; antifoaming agents; wetting agents; leveling agents; curing agents; thickening agents;

As to the method of applying or impregnating the undercoating agent coating liquid onto the release substrate , various apparatuses such as an air knife coater, a roll coater, a gravure coater, a bar coater, a blade coater, a rod blade coater, and a size press coater can be used. Is appropriately used. The amount of coating or impregnation is preferably adjusted in a range of about 0.1 to 20 g / m ² by dry weight, and particularly preferably about 1 to 10 g / m ² .

In the release sheet of the present invention, as the release substrate, various fiber sheets having a basis weight of about 30 to 300 g / m ² and a thickness of about 30 to 300 μm are used.

The release agent applied on the undercoat layer is not particularly limited, and various silicone compounds, fluorine compounds and the like are applied in a usual manner.

The release sheet comprising the release substrate, the primer layer and the release agent layer used in the pressure-sensitive adhesive sheet of the present invention thus obtained is obtained by adding a pigment to an emulsion having a specific monomer composition and a glass transition temperature on the substrate. Since the undercoating layer is formed as described above, the occurrence of curling is particularly effectively prevented, and an adhesive paper excellent in paper passage suitability and copy suitability can be formed.

A release sheet is manufactured by forming a release agent layer on the substrate provided with the undercoat layer. The release sheet includes a release agent layer surface and chloroprene rubber (Shore A hardness).
It is preferable that the coefficient of dynamic friction (JIS P 8147) with respect to 65 ± 2 °) is 0.2 or more. When the coefficient of kinetic friction is less than 0.2, the effect of preventing the adhesive from adhering to the processing blade or the cut surface is poor, which causes poor paper traveling in an ink jet printer.

Specific examples of the release agent giving the dynamic friction coefficient include SD-7239, BY2 manufactured by Dow Corning Toray Co., Ltd.
4-162, LTC-300B, LTC-350A, L
TC-350G, LTC-370G, BY14-40
3, BY14-405, BY14-407, BY14-
413, BY14-414, BY14-411, BY1
4-420, KS-845, KS- manufactured by Shin-Etsu Chemical Co., Ltd.
770, KNS-202A, KNS-305, KNS-
316, KNS-319, KNS-320, X-62-
A232, X-62-1233 and the like.

The pressure-sensitive adhesive sheet of the present invention, by combining the surface substrate obtained as described above and a release sheet, sufficiently satisfies the ink receptivity and the writability, as well as the loss of the label and the pressure-sensitive adhesive. Extrusion can be prevented.

The method for forming the pressure-sensitive adhesive sheet is not particularly limited, and the pressure-sensitive adhesive layer is formed by applying a pressure-sensitive adhesive on the release agent layer of the release sheet according to a conventional method, and drying it as necessary. Then, the surface base material is bonded and finished by performing humidity control or the like.

The pressure-sensitive adhesive can be obtained by polymerization as follows. A seed polymer mainly composed of at least one ester group-containing monomer selected from the group of (meth) acrylates is polymerized. The seed polymer is preferably a polymer having a glass transition temperature [Tg] of 215 to 303K. If the Tg is lower than 215 K, the cohesive strength is significantly reduced, and if the Tg is higher than 303 K, the adhesive strength tends to be reduced. The seed polymer is
Those produced by a known emulsion polymerization method (for example, a primary charge polymerization method, a monomer addition polymerization method, a pre-emulsion addition polymerization method, etc.) are preferable.

The average particle size of the seed polymer is 0.15 to 0.35.
μm, more preferably 0.2 to 0.3 μm. 0.15μm
If it is less than 0.35 μm, an emulsion having high viscosity and poor coatability is produced by the second stage emulsion polymerization (seed polymerization), and if it is more than 0.35 μm, the distribution of the tackifier resin in the particles of the produced copolymer is reduced. Become irregular,
The bonding performance cannot be sufficiently improved.

As the seed polymer, those having a polymerization conversion of the monomer of 98% or more (the amount of the residual monomer is less than 2%) are desirable. In an emulsion having a low polymerization conversion (a large amount of residual monomer), the reaction system may be destabilized in the above-mentioned second stage emulsion polymerization, or coarse particles in which the tackifier resin is aggregated may be generated. The seed polymer is a (meth) acrylate, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, (meth) acrylate. Acrylic acid-t-
Butyl, cyclohexyl (meth) acrylate, (meth)
Main component is at least one selected from 2-ethylhexyl acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate; ethylene, vinyl chloride, vinylidene chloride, ethylenically unsaturated A copolymer comprising at least one copolymerizable monomer selected from a carboxylic acid, a crosslinking monomer, (α-methyl) styrene, N-alkyl (meth) acrylamide, and (meth) acrylonitrile is preferred. Examples of ethylenically unsaturated carboxylic acids include, for example, acrylic acid, methacrylic acid, crotonic acid, itaconic acid,
Maleic acid, maleic anhydride, alkyl group with 1 carbon atom
To 12 monoalkyl malates, hydroxyethyl (propyl) monomalates, phthalic acid, itaconic acid monoalkyl (C1 to C12) esters, and the like. Also,
Examples of the crosslinkable monomer include (meth) acrylic acid-
Hydroxy group-containing monomers such as 2-hydroxyethyl, 2-hydroxypropyl (meth) acrylate, 3-hydroxyethyl (meth) acrylate, polyethylene glycol or polypropylene glycol, and glycidyl (meth) acrylate Such as an epoxy group-containing monomer, a monomer having a -CONH ₂ group or a methylol group such as (meth) acrylamide and diacetone acrylamide, divinylbenzene, divinylsilane, diallyl phthalate, cyclopentadiene, methylenebisacrylamide, diallyl maleate, and tetraallyl Monomers having two or more ellenic unsaturated bonds, such as oxyethane, can be mentioned.

As the pressure-sensitive adhesive of the present invention, a copolymer obtained by applying an emulsion of the copolymer produced by the above-described first-stage emulsion polymerization and continuously performing the second-stage emulsion polymerization is used. Here, in the second stage of emulsion polymerization, an alkyl (meth) acrylate having an alkyl group having 4 to 18 carbon atoms is mainly used, and a functional group selected from an ethylenically unsaturated carboxylic acid and a crosslinkable monomer is used. At least one of group-containing monomers, or further, a vinyl ester, a (meth) acrylate having an alkyl group having 1 to 3 carbon atoms,
An emulsion monomer mixture obtained by adding a tackifier resin to at least one nonionic monomer selected from (α-methyl) styrene and benzyl (meth) acrylate is added to the first-stage seed polymer to polymerize the mixture. Is done.

Examples of the tackifier resin used in the present invention include rosin resins such as raw rosin, hydrogenated rosin, hydrogenated rosin ester, disproportionated rosin ester, polymerized rosin ester, α-pinene resin, β -Polyterpene resins such as pinene resin, dipentene resin, terpene-phenol resin, Heylets (Mitsui Petrochemical), Quinton (Zeon Corporation), Tackroll (Sumitomo Chemical), Estechoretz 1000 (Esso Chemical), etc. Aromatic petroleum resin, Neopolymer S (manufactured by Nippon Synthetic Resin), petrozine (manufactured by Mitsui Petrochemical), petroleum (such as petroleum (manufactured by Toyo Soda)), high resin (manufactured by Toho Petrochemical), Tack Ace (Mitsui Petrochemical), Estechoretz 200
Pure monomer copolymerized petroleum resin such as Esso Chemical Co., Ltd., alicyclic petroleum resin such as Alcon (Arakawa Chemical Co.), Estechoretz (Esso Chemical Co.), polyamide resin such as Tomide (Fuji Kasei Kogyo) Epoxy resins such as EPOMIC (manufactured by Mitsui Petrochemical Epoxy), Epote (manufactured by Mitsui Petrochemical Epoxy), natural rubber, isoprene rubber, styrene butadiene rubber, styrene-butadiene block polymer, styrene-isoprene block polymer And an elastomer such as ethylene-isoprene-styrene block polymer.

The pressure-sensitive adhesive of the present invention is prepared by adding 100 parts by weight of the first-stage seed polymer to the second-stage polymers 300 to 3,
A mixture of 000 parts by weight is used. When the amount is less than 300 parts by weight, no improvement in adhesive strength is observed, and when the amount exceeds 3,000 parts by weight, the stability of emulsion polymerization and the stability of the formed emulsion deteriorate, which is not preferable.

When the adhesive forming the adhesive layer has a tensile strength (JIS K 6301) of 0.5 to 2.0 kg / cm ² and an elongation (JIS K 6301) of 1,500 to 3,000%, It is preferable because the adhesion of the pressure-sensitive adhesive to the cutting blade and the cut surface when the pressure-sensitive adhesive sheet is cut is further controlled.

[0058]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted to such specific Examples. In the examples, "parts" and "%" indicate "parts by weight" and "% by weight", respectively, unless otherwise specified.

Example 1 [Surface Substrate] A fourdrinier paper machine was prepared by adding 5 parts of talc, 0.2 part of rosin emulsion size and 2 parts of sulfuric acid band to a pulp slurry of 20 parts of NBKP and 80 parts of LBKP having a freeness of 500 ml. The paper was made so as to have a rice tsubo of 64 g / m ² to obtain a base paper. This base paper was coated with a 3% concentration coating solution containing 0.05% by weight of a cationic amide-based surface sizing agent in a 4: 1 ratio of polyamide epichlorohydrin resin and oxidized starch as cationic synthetic resins as main components. Liquid volume
Coat with a size press to 40 g / m ² , dry,
Machine calendering was performed to obtain a surface substrate having a paper moisture of 6.5%.

[Release Sheet] 20 g of 2-hydroxyethyl methacrylate, 240 g of butyl acrylate, 40 g of acrylonitrile, 20 g of acrylic acid, 68 methyl methacrylate
g, N-methylol acrylamide 12 g, alkylphenyl ether sulfate type emulsifier (manufactured by Sanyo Kasei Co., Ltd., trade name "Eleminol ES-70") 10 g, ion-exchanged water
An emulsion monomer mixture (A) consisting of 170 g was prepared.

Next, 240 g of ion-exchanged water and 2 g of the same emulsifier as above were placed in a two-liter four-necked flask equipped with a stirrer, cooler, dropping funnel, nitrogen suction tube and thermometer.
Charge potassium persulfate (0.8 g) and replace with nitrogen at 70 ° C
After the temperature was raised to 1, the emulsified monomer mixture (A)
/ 6 was added dropwise. When the reaction rate reached 90%, the remaining emulsified monomer mixture (A) was added dropwise over 2 hours to polymerize. After completion of the dropwise addition, the mixture was aged at 70 ° C. for 2 hours to complete the reaction. After completion of the aging, the contents of the flask are cooled to 40 ° C., an aqueous sodium hydroxide solution is added to carry out a neutralization reaction, and after completion of the reaction, the mixture is vigorously stirred to obtain an aqueous copolymer (A) used in the present invention.
I got The glass transition temperature of the obtained copolymer is 4 ° C. The amount of emulsifier is 3.0%.

100 parts of an aqueous copolymer (a), 100 parts of wet heavy calcium carbonate (trade name "Hydrocarb K-9" manufactured by Bihoku Powder Chemical Industry Co., Ltd.), lubricant (trade name "Nopcoat C-" manufactured by San Nopco Co., Ltd.) 104 ") 1 part, 0.6 part of antifoaming agent (manufactured by San Nopco, trade name" Nopco 1407K "), concentration 45%
Preparation of undercoat layer coating liquid of 49g / m ² tsubo, thickness 65μm
Quality paper (the peeling substrate) was coated as dry weight by a rod blade coater is 5 g / m ² and dried to primer
A release substrate having a layer was obtained.

A silicone release agent (trade name “KS-845” manufactured by Shin-Etsu Chemical Co., Ltd. ) is applied to the surface of the undercoat layer of the release substrate.
A 9% toluene solution with a coefficient of kinetic friction of 0.27) is dried at 1.
It was coated with a bar coater so as to obtain 0 g / m ² and dried to obtain a release sheet.

[Adhesive] First, a seed emulsion was prepared as follows. 30 parts of vinyl acetate, acrylic acid-2
-A monomer mixture of 68 parts of ethylhexyl, 2 parts of acrylic acid, and 0.3 part of N-methylolacrylamide was added to sodium polyoxyethylene alkylphenyl ether sulfate.
Part, sodium dodecylbenzenesulfonate 0.2 part, polyoxyethylene nonylphenyl ether (HLB about 1 part)
0) 1 part, 0.3 part of sodium acetate, and 30 parts of ion-exchanged water were added to an emulsifier aqueous solution and stirred to form a pre-emulsion.

In a reaction vessel equipped with a stirrer, a thermometer, and a cooling pipe, 0.2% sodium dodecylbenzenesulfonate was placed.
Part, polyoxyethylene nonylphenyl ether (HL
B about 10) 1 part, sodium acetate 0.3 part, ion exchange water 30
Part of the emulsifier aqueous solution, and the temperature of the solution was raised to 75 ° C. while stirring and passing nitrogen gas.
100 was added and the initial polymerization was carried out for 30 minutes, and then the remaining amount was added dropwise over 4 hours, and the polymerization was carried out while maintaining the temperature at 75 to 80 ° C. After completion of the dropwise addition, the temperature was further maintained at 80 ° C. to perform late-stage polymerization to obtain a seed emulsion. The seed emulsion obtained here has a solid content of 50%, viscosity of 100 cps, pH
3.0, the average particle size was 0.23 μm, and the glass transition temperature of the copolymer was -44 ° C.

Next, a tackifier resin copolymer emulsion was prepared as follows. 30 parts of methyl acrylate,
A monomer mixture of 2-ethylhexyl acrylate 58 parts and acrylic acid 2 parts (the glass transition temperature of the copolymer is -45.
C.) and 10 parts of a tackifier (trade name "Resin Super Ester A-100" manufactured by Arakawa Chemical Co., Ltd.) were mixed with sodium polyoxyethylene alkyl phenyl ether sulfate 1
Part, sodium dodecylbenzenesulfonate 0.3 part, polyoxyethylene nonylphenyl ether (HLB about 1 part)
0) 1 part, 0.4 part of sodium acetate and 30 parts of ion-exchanged water were added to an emulsifier aqueous solution and stirred to form a pre-emulsion.

Further, 20 parts of the above-mentioned seed emulsion and 18 parts of ion-exchanged water were charged into a reaction vessel equipped with a stirrer, a thermometer, and a cooling pipe. Then, a solution of 132.7 parts of the pre-emulsion, 0.3 parts of potassium persulfate, and 7 parts of ion-exchanged water was added to 4 parts.
The polymerization was carried out dropwise over time. The resulting copolymer emulsion had a solid content of 65%, a viscosity of 400 cps,
H3.5 and average particle diameter 0.45 μm.

After the copolymer emulsion was neutralized with 25% ammonia water, a thickening agent (trade name “Bissurf 1400”, manufactured by Kao Corporation) was added thereto to obtain a viscosity of 5,000 cp.
s to obtain an adhesive.

[Adhesive Sheet] The above-mentioned adhesive (tensile strength: 2.0 kg / cm ² , elongation: 1,500%) was applied to the release agent layer surface of the release sheet by a reverse roll coater and dried.
Coating was performed to 17 g / m ² and drying was performed. Subsequently, the surface base material was superimposed on the surface of the pressure-sensitive adhesive layer, and bonded with a press roll to obtain a pressure-sensitive adhesive sheet.

Example 2 The surface substrate was the same as in Example 1. The release sheet was prepared by applying the aqueous copolymer (a) in Example 1 (manufactured by Chuo Rika Co., Ltd.,
Product name "Licabond ET-L236" glass transition temperature-
11 ° C.) and a release substrate having an undercoat layer was obtained in the same manner as in Example 1 except that the coating dry weight of the undercoat was 4.5 g / m ² . , trade name and "LTC-350A" dynamic friction coefficient 0.21), except that the dry coating amount of 1.1 g / m ² was release sheet in the same manner as in example 1. A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that this release sheet was used.

Example 3 The surface base material was the base paper of Example 1, and a cationic polyamide resin and polyvinyl alcohol were used as the cationic polymer resin in a ratio of 4: 2. 35% of the coating liquid with a concentration of 4%
/ M ² by a size press, dried and machine-calendered to obtain a surface substrate having a paper moisture of 6.5%. Except for using this surface substrate, a release sheet and an adhesive sheet were obtained in the same manner as in Example 1.

Example 4 [Surface substrate] A papermaking raw material obtained by adding 8 parts of calcium carbonate and 0.2 parts of an alkylketene dimer sizing agent to a pulp slurry of 10 parts of NBKP having a freeness of 520 ml and 90 parts of LBKP having a freeness of 500 ml was used. Paper was made with a Fourdrinier paper machine so as to have a rice tsubo of 64 g / m ² to obtain a base paper. In this base paper, a cationic polyamide resin and polyvinyl alcohol were used as a cationic polymer resin in a ratio of 4: 1.
A coating solution having a concentration of 4% containing a styrene-acrylic surface sizing agent of 0.06% by weight is applied by a size press so that the amount of the coating solution becomes 40 g / m ^2, and subjected to a drying machine calendering process.
A surface substrate having a paper moisture of 6.5% was used.

[Release Sheet] A release substrate having an undercoat layer was obtained in the same manner as in Example 1, and a silicone release agent (trade name “LTC-300B”, dynamic friction coefficient 0.21 manufactured by Toray Dow Corning Co., Ltd.) was used. Example 1 was repeated except that the coating amount was 1.0 g / m ² .

[Adhesive Sheet] An acrylic adhesive (manufactured by Kanebo NSC, trade name "Durotack AQ-432T") having a tensile strength of 1.5 kg /
cm ² and an elongation of 2,500%) using a slot die coater so that the dry coating amount would be 14 g / m ² and dried.
Subsequently, the surface base material was superimposed on the surface of the pressure-sensitive adhesive layer, and bonded with a press roll to obtain a pressure-sensitive adhesive sheet.

Example 5 [Surface base material] A surface base material was prepared in the same manner as in Example 1 except that the base paper was changed to a polyamide epichlorohydrin resin and oxidized starch as the cationic polymer resin in a ratio of 4: 2. And

[Release Sheet] A release substrate having an undercoat layer was obtained in the same manner as in Example 2, and a silicone release agent (trade name “SD-7239”, dynamic friction coefficient 0.25, manufactured by Toray Dow Corning Co., Ltd.) was used. the coating amount other than changing as a 1.0 g / m ² example 2
Same as.

[Adhesive Sheet] In Example 1, the tackifier resin was manufactured by Yasuhara Yushi Co., Ltd. under the trade name “YS Resin TO-
An adhesive was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive was changed to 105 ". The above-mentioned release sheet and the above-mentioned adhesive (a tensile strength of 1.8
kg / cm ² , elongation 2,500%) by a reverse roll coater so that the dry coating amount is 15 g / m ^2, and the above-mentioned surface base material is superimposed on the adhesive layer surface and bonded with a press roll. An adhesive sheet was obtained.

Example 6 [Surface base material] A styrene-acrylic surface sizing agent was prepared in the same manner as in Example 4 except that a cationic polyamide resin and polyvinyl alcohol were used as the cationic polymer resin in a ratio of 4: 2. Example 4 was carried out in the same manner as in Example 4 except that a coating solution having a concentration of 4% containing 0.07% by weight was applied by a size press.

[Release Sheet] A release substrate having an undercoat layer was obtained in the same manner as in Example 2, and a silicone release agent (trade name “LTC-350A”, dynamic friction coefficient 0.21 manufactured by Toray Dow Corning Co., Ltd.) was used. Example 2 was repeated except that the coating amount was 1.0 g / m ² .

[Adhesive Sheet] An acrylic adhesive (manufactured by Kanebo NSC, trade name "Durotack AQ-432T") having a tensile strength of 1.5 kg /
cm ² and an elongation of 2,500%) using a slot die coater so that the dry coating amount would be 14 g / m ² and dried.
Subsequently, the surface base material was superimposed on the surface of the pressure-sensitive adhesive layer, and bonded with a press roll to obtain a pressure-sensitive adhesive sheet.

An adhesive was obtained in the same manner as in Example 1 except that 0.3 part of N-methylol methacrylamide was added to the monomer mixture in which the tackifier resin was dissolved. The above release sheet and the above adhesive (tensile strength
1.2 kg / cm ² , elongation 1600%) with a knife coater so that the dry coating amount is 17 g / m ^2. An adhesive sheet was obtained.

Comparative Example 1 A surface substrate was obtained in the same manner as in Example 1 except that no cationic amide-based surface sizing agent was added. An adhesive sheet was obtained in the same manner.

Comparative Example 2 In Example 1, the cationic amide-based surface sizing agent was used.
A surface substrate was obtained in the same manner as in Example 1 except that the content was 0.002%, and an adhesive sheet was obtained in the same manner as in Example 1 except that this surface substrate was used.

Comparative Example 3 In Example 1, the cationic amide-based surface sizing agent was used.
A surface substrate was obtained in the same manner as in Example 1 except that the content was 0.3%. An acrylic pressure-sensitive adhesive (trade name “Acronal YJ8655-DB”, manufactured by Mitsubishi Yuka Birdish Co., Ltd.) having a tensile strength of 2.1 kg / c was applied to the release agent layer of the release sheet of Example 2.
(m ² , elongation: 3,200%) using a reverse roll coater so that the dry coating amount was 20 g / m ² , followed by drying.
Subsequently, the above-mentioned surface substrate was superimposed on the surface of the pressure-sensitive adhesive layer and bonded with a press roll to obtain a pressure-sensitive adhesive sheet.

The following evaluations were performed on the nine types of pressure-sensitive adhesive sheets thus obtained, and the results are shown in Table 1. [Dryability] A predetermined pattern is recorded by a recording device (Canon Canoward α-50), and the recording portion immediately after recording is rubbed with gauze to visually evaluate stains due to spread of ink. ：: Not dirty ×: Stained [Recording density] The above recording part was measured with a densitometer (Macbes-RD914)
Measure with [Evaluation of bleeding by water-based pen writing] Evaluated in accordance with J-TAPPI paper pulp test method No.12-76, the larger the number, the less bleeding and the sharper the line. (Adhesive force) The adhesive force of the surface of the adhesive to the stainless steel plate, according to JIS Z 1528, affixed the adhesive sheet to the stainless steel plate two reciprocations in a room at 20 ° C and 60 RH with a 2 kg roller. 300 by Instron tensile tester
The load (g / 25 mm) when peeled at an angle of 180 ° at a pulling speed of mm / min is measured. [Cutability] Cut the adhesive sheet 20 times in length to 20 cm in length and 15 cm in width, stack 100 sheets and cut them continuously 20 times in the width direction using a guillotine test machine (trade name: CM-450, manufactured by Rikugo Seisakusho). The amount (mg) of the adhesive adhered to the blade was measured.

[0086]

[Table 1]

[0087]

As is clear from Table 1, the pressure-sensitive adhesive sheets obtained in Examples of the present invention have ink receiving properties, recording densities,
The pressure-sensitive adhesive sheet has excellent writing suitability, suppresses the sticking-out of the pressure-sensitive adhesive in guillotine cutting, and has excellent paper-feeding suitability in a recording apparatus.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph for explaining an initial permeation rate according to the present invention, wherein an upper graph shows a movement of a permeation amount with respect to time, and a lower graph shows immersion of a sample into a liquid surface.

[Explanation of symbols]

 S: sample W: aqueous solution

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-311786 (JP, A) JP-A-4-209682 (JP, A) JP-A-2-286767 (JP, A) JP-A-2-2 308881 (JP, A) JP-A-63-75199 (JP, A) JP-A-2-80482 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09J 7/04 B41M 5 / 00 D21H 19/20 D21H 19/24

Claims (3)

(57) [Claims] 1. A pressure-sensitive adhesive sheet comprising a surface substrate, a pressure-sensitive adhesive, a release agent, a primer, and a release substrate , wherein the surface substrate has a base paper, a cationic synthetic resin and a cationic surface sizing agent of 0.003 to 0.003.
Adhesive material consisting of a coating agent containing 0.2% by weight (based on the total solid content)
In the coating, at least one kind of (meth) acrylic acid ester having a hydroxyl group in a molecule as a main component of a primer and at least one kind of other vinyl monomer copolymerizable therewith is obtained by emulsion copolymerization. and copolymers to be, the
A pressure-sensitive adhesive sheet comprising 50 to 150 parts by weight of a pigment with respect to 100 parts by weight of a copolymer . 2. A seed polymer whose main component is a (meth) acrylate ester having an average particle diameter of 0.15 to 0.35 μm.
The solid content of a pre-emulsion containing 100 parts by weight of an emulsion containing a monomer mixture containing (meth) acrylic acid ester as a main component, a tackifier, an emulsifier, and water is 300 to 300 parts by weight.
The pressure-sensitive adhesive sheet according to claim 1, wherein the tackifier resin is a pressure-sensitive adhesive obtained by sequentially adding 3,000 parts by weight and emulsion-copolymerizing the pressure-sensitive adhesive resin selectively coexisting in the polymer particles. 3. The adhesive has a tensile strength of 0.5 to 2.0 kg / cm.
^2. The pressure-sensitive adhesive sheet according to claim 1, which has an elongation of 1,500 to 3,000%.