JP2837486B2 - Adhesive sheet and method for producing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive sheet, and more particularly, to a fixing property of a toner in a transfer and fixing process without curling or jamming during paper passing in a copying machine. It relates to an excellent adhesive sheet.

[Background Art] Adhesive sheets are used in a wide range of applications such as home use, office use, and commercial use as labels, stickers, patches, delivery slips, and the like. In recent years, the demand for an adhesive sheet which is used as a simple printing sticker label or an address sticker label by copying a desired image with an electrophotographic copying machine has been rapidly growing.

The pressure-sensitive adhesive sheet is simply a pressure-sensitive adhesive layer formed between a surface substrate and a release sheet, and paper, a film, a metal foil, or the like is used for the surface substrate, and glassine is used as the release sheet. A material obtained by applying a release agent such as a silicone compound or a fluorine compound to a high-density base paper such as paper, clay-coated paper, or polylaminate base paper is used. As the pressure-sensitive adhesive, a solvent-type pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, a hot-melt-type pressure-sensitive adhesive, or the like is used.

Such a pressure-sensitive adhesive sheet has a drawback in that curling is likely to occur due to the configuration in which substrates having different characteristics (in particular, hygroscopicity) are bonded to each other, and paper passing failure occurs during copying by a copying machine or the like.

That is, as a general production process of a pressure-sensitive adhesive sheet, a release agent is usually applied to a release substrate and dried, and then the pressure-sensitive adhesive is applied and dried on the release agent layer and then bonded to a surface substrate. For this reason, in combination with the difference in the composition structure of the two substrates, the release substrate shrinks in these drying steps, and curl occurs immediately when uneven moisture absorption or water absorption occurs due to a change in the external environment or the like. . In particular, when heavy beating or high-density paper such as glassine paper is used as the release substrate, the shrinkage ratio during drying is high, so that the fibers absorb swelling and shrinkage caused by moisture absorption, water absorption, or re-drying. Since the gap to be formed is extremely small, curling is significantly generated.

Such curl of the adhesive sheet causes poor paper passing and poor transfer when copying with a copying machine, and, for example, printing, die cutting, sheet cutting, and the like on the adhesive sheet to process them into labels and seals. However, it causes troubles such as poor paper feed, paper misalignment, and printing misalignment, and has been a very serious obstacle in workability and quality.

Conventionally, in order to correct the curl of the pressure-sensitive adhesive sheet, proposals have been made for the use of a curl breaker that sharply bends the pressure-sensitive adhesive sheet in a direction opposite to the curl direction, the installation of an air conditioner, a correction method by steam diping, and the like. On the other hand, there is also a method of performing curl correction by a method such as applying water to the back surface of the peeling substrate. However, the effect is too strong and the curl to the peeling substrate side becomes too large, causing a jamming trouble during paper passing in a copying machine. In addition, there is a problem that the process is complicated, and a satisfactory improvement effect is not obtained.

Furthermore, in the case of an adhesive sheet using, for example, high-quality paper as the surface base material, the toner is not sufficiently fixed to the surface base material in the process of transferring and fixing the toner on the photoreceptor of the electrophotographic copying machine to the surface base material. was there.

On the other hand, from the viewpoint of resource conservation, requests for the reuse of waste paper contained in municipal solid waste have been highlighted. In other words, the paper output from ordinary households and offices is increasing the amount of municipal waste. For this reason, there is a strong demand for recovering paper discharged as garbage and reuse of used paper as a raw material.

"Problems to be Solved by the Invention" In view of the current situation, the inventors of the present invention have made an effort to improve the fixability of toner in a transfer and fixing process without curling of an adhesive sheet or jamming at the time of passing through a copying machine. As a result of intensive research, the main component is an acrylic ester copolymer emulsion having a specific glass transition temperature obtained by emulsifying and copolymerizing a specific monomer on the surface of the surface base material where the adhesive is not laminated. A treatment liquid containing a water-soluble plasticizer as a main component is coated or impregnated with the treatment liquid to be applied, and the surface of the release substrate on which the release agent is not laminated is coated. In addition, it has been found that the above-mentioned difficulties can be solved very efficiently by incorporating a specific amount of recycled pulp using waste paper as a raw material, and the present invention has been completed.

"Means for Solving the Problems" The present invention relates to a pressure-sensitive adhesive sheet formed by sequentially laminating a release substrate, a release agent, a pressure-sensitive adhesive, and a surface substrate. Specular reflection type smoothness meter in which the pulp composition contains recycled pulp made of waste paper as a raw material in an amount of 10% by weight or more, and the surface of the sheet containing the recycled pulp has a smoothness of 20 kg / cm ² under pressure. Using a base paper having a value of 8% or more as measured by the above method, and furthermore, (i) an ethylenically unsaturated carboxylic acid-containing monomer (ii) having a glass transition temperature of a homopolymer An ethylenically unsaturated bond-containing monomer having a temperature of 50 ° C. or higher; and (iii) another monomer copolymerizable with these monomers (provided that at least one of the monomers (ii) and (iii) (Including acrylic acid ester monomer) A treatment liquid containing an acrylate copolymer emulsion having a glass transition temperature of 0 to 100 ° C. as a main component is applied, or a surface substrate is impregnated with the treatment liquid, and the release agent layer of the release substrate is not laminated. A pressure-sensitive adhesive sheet characterized by being coated on the surface with a treatment liquid containing a water-soluble plasticizer as a main component, and further, upon producing the pressure-sensitive adhesive sheet, a release sheet provided with a release agent on a release substrate. A method for producing a pressure-sensitive adhesive sheet, characterized in that after applying and drying an adhesive, and immediately before bonding the surface substrate, the surface substrate is heat-treated at 50 to 100 ° C.

[Function] In the pressure-sensitive adhesive sheet of the present invention, as the release substrate and / or the surface substrate sheet, a base paper containing 10% by weight or more of recycled pulp made from waste paper in the pulp composition is used. Chemical pulp depending on pulp composition
It has better dimensional stability than 100% base paper, and curling is suppressed even when the external environment changes. By the way,
If the recycled pulp is less than 10% by weight, a sufficient improvement effect cannot be expected.

Specific examples of raw paper recycled pulp raw materials include, for example, top white, ruled white, cream top white, card, special white, medium white, imitation,
Colors, Kent, White Art, Tokubikiri, Tokubikiri, Newspapers, Magazines, etc. (Recovered Paper Standard Quality Standards Table; Summary of Used Paper Recycling Promotion Center). Recycled pulp is generally obtained by appropriately combining a defibration step, a rough selection step, a fine selection step, a deinking step, and a bleaching step. In the disaggregation process,
The low-concentration pulper, high-concentration pulper, etc., screens and cleaners in the rough and fine selection processes, and the deinking process, the flotation method, washing method and eclectic method, etc. Is appropriately selected depending on the quality of the product.

In addition, when the obtained recycled pulp is blended in an untreated state, there is a concern that the smoothness of the base paper surface or the paper strength of the base paper may be reduced.
For this purpose, it is desirable to treat the pulp with a beater, which is a pre-process of papermaking. Specifically, it is preferable to reduce the Canadian Standard Freeness of untreated recycled pulp within a range of about 30 to 150 ml. By the way, with a light beating process of less than 30 ml, sufficient smoothness improvement effect cannot be obtained,
On the other hand, when a strong beating treatment exceeding 150 ml is performed, the dimensional stability of the obtained base paper is deteriorated, and the desired effects of the present invention cannot be obtained.

Refining machines in this case include conical refiners,
Although a single disc refiner, a double disc refiner, or the like is used, the use of a double disc refiner is more preferable in consideration of power load.

In the pressure-sensitive adhesive sheet of the present invention, the recycled pulp is
The base paper containing more than 1% by weight is used, and the surface of the base paper is further subjected to a specular reflection type smoothness meter (measurement pressure: 20 kg / c
It is necessary to finish so that the measured value in m ² ) is at least 8%, more preferably at least 14%. Therefore, in the present invention,
It is extremely important to satisfy these two technical requirements simultaneously.

Here, the specular reflection type smoothness meter is a device for measuring the smoothness by pressing a paper against a glass surface under a constant pressure condition. It is not affected by the air permeability of the paper, such as the Beck Smoothness Meter and Parker Print Surf, which are air leak type smoothness measuring instruments. Moreover, it was found that the desired effect of the present invention could be judged very appropriately by the value measured with this specular reflection type smoothness meter (measuring pressure: 20 kg / cm ² ), and finally the present invention was completed. .

By the way, the regular reflection type smoothness meter of the base paper surface (measurement pressure: 20K
g / cm ² ), when the measured value is less than 8%, the toner on the photoreceptor of the electrophotographic copying machine is transferred and fixed to the surface substrate even if the recycled pulp is contained in the base paper at 10% by weight or more. In the process, the toner does not sufficiently fix to the surface substrate, and the desired effect of the present invention cannot be obtained.

For smoothing the base paper surface, a machine calender consisting only of a metal roll provided at the end of a fourdrinier or round net paper machine can be used, but a super calender consisting of a metal roll and an elastic roll Can also be used. In particular, it is effective to use a gloss calender, a soft calender or the like in combination with an on-machine or an off-machine.

As the metal roll, for example, a chilled roll, an alloy chilled roll, a steel roll, and a metal roll with a hard chrome plated roll surface are appropriately selected and used.
As the elastic roll, for example, natural rubber, styrene rubber, nitrile rubber, chloroprene rubber, chlorosulfonated ethylene rubber, butyl rubber, polysulfide rubber, silicon rubber, fluorine rubber, urethane rubber, aromatic polyamide resin,
Various plastic resins such as polyimide resin, polyether resin, polyester resin, and polycarbonate resin,
An elastic roll made of cotton, paper, wool, tetron, nylon, or a mixture thereof is appropriately selected and used.

In addition, on-machine smoothing is preferred for efficiency, and in this case, Shore D hardness (ASTM standard, D-2240)
A calender composed of elastic rolls of 42 to 98 degrees is particularly preferably used. Among them, elastic rolls of urethane rubber, aromatic polyamide resin, a mixture of paper and wool, a mixture of wool and tetron, a mixture of wool and nylon, a mixture of paper and wool and tetron, a mixture of paper, wool and nylon, and the like are preferable.
In particular, elastic rolls using urethane rubber and aromatic polyamide resin are easy to handle, have a long roll life,
Moreover, it is most preferably used in order to efficiently exhibit the desired effects of the present invention.

The elastic roll as described above is softer than a normal elastic roll, and easily generates heat even under stable operating conditions. In particular, the tendency is remarkable in an elastic roll using urethane rubber. The physical properties of the elastic body become unstable due to the heat generation phenomenon, and in the extreme case, the heat accumulated in the elastic body itself may cause melting damage. This is a preferred embodiment, and various countermeasures such as cooling from the outside, a change in the roll diameter, and a change in the thickness of the elastic body are appropriately adopted.

For on-machine super calenders and on-machine soft calenders composed of metal rolls and elastic rolls, see Paper Pulp Technology Times August 1987 (p. 31) and May 1988 (p. 10). Etc. are introduced. These calendering conditions are appropriately adjusted according to the number of nips, nip linear pressure, machine speed, and the like.

In the present invention, the compound used for coating or impregnating the surface substrate is a polymer obtained by copolymerizing a specific monomer mixture, and the glass transition temperature of the polymer is 0 to 100.
C., more preferably 20-70.degree. C., is selectively used. By using such a specific polymer, the fixability of the toner in a copying machine is greatly improved. However, when the glass transition temperature is lower than 0 ° C., the adhesiveness of the film becomes too strong,
Blocking may occur during winding or jamming may occur due to adhesion inside the machine when paper is passed through a copying machine.On the other hand, when the temperature exceeds 100 ° C, the obtained film becomes too hard, and the side where the processing liquid is applied may be applied. There is a disadvantage that curling is caused, thereby deteriorating the fixing property of the toner, and causing jamming due to curling during paper passing. Therefore, it is necessary to adjust the glass transition temperature of the acrylate copolymer emulsion within a required range so that the desired effect of the present invention is exhibited by adjusting the monomer composition.

The specific acrylic acid ester copolymer emulsion used in the present invention comprises (i) an ethylenically unsaturated carboxylic acid-containing monomer, and (ii) an ethylenically unsaturated monomer having a glass transition temperature of 50 ° C. or higher of a homopolymer. Bond-containing monomers, and (iii) other monomers copolymerizable with these monomers (provided that at least one of the monomers (ii) and (iii) contains an acrylate monomer) ).

(I) Examples of the monomer containing an ethylenically unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, monoalkylmaleic acid, monoalkylitaconic acid, monoalkylfumaric acid and the like. Is mentioned. Of course, two or more of them can be used in combination as needed.

When the proportion of the ethylenically unsaturated carboxylic acid-containing monomer in the copolymer is less than 1% by weight of all monomers, the dispersion stability of the obtained copolymer becomes insufficient,
On the other hand, if it exceeds 10% by weight, the drying property may be insufficient, so that it is desirable to copolymerize the ethylenically unsaturated carboxylic acid-containing monomer in the range of 1 to 10% by weight.

The (ii) ethylenically unsaturated bond-containing monomer having a glass transition temperature of 50 ° C. or higher of the homopolymer constituting the acrylate copolymer emulsion used in the present invention includes, for example, methyl methacrylate and methacrylic acid. Ethyl, vinyl chloride, styrene, (meth) acrylonitrile, tert-butyl acrylate, methacrylic acid-iso
-Propyl and the like. Of course, two or more of them can be used in combination as needed.

The proportion of the monomer having an ethylenically unsaturated bond in which the glass transition temperature of these homopolymers is 50 ° C. or higher in the copolymer is adjusted in the range of 50 to 90% by weight of all the monomers. It is desirable to be done.

In the present invention, among the ethylenically unsaturated bond-containing monomers having a glass transition temperature of 50 ° C. or higher of these homopolymers, in particular, methyl methacrylate, (meth) acrylonitrile, and styrene have copolymerization rates and glass transition temperatures. It is preferably used in terms of adjusting the temperature and the like.

Further, (iii) other monomers copolymerizable with the above-mentioned monomers constituting the acrylate copolymer emulsion used in the present invention include, for example, butyl (meth) acrylate and (meth) acrylate. Hexyl acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, (meth)
Stearyl acrylate, methyl acrylate, ethyl acrylate, propyl (meth) acrylate, vinyl acetate, ethylene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, di (meth) acrylate
Trimethylene glycol acrylate, (poly) ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, di (meth) acrylate ) (Poly) propylene glycol acrylate, 1,3-butylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, divinylbenzene, di (meth) acrylate Acrylic acid-1,4
-Butanediol, 1,6-hexanediol di (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide,
N-butoxymethyl (meth) acrylamide, N, N'-
Methylene bis (meth) acrylamide and the like can be mentioned.

The proportion of the other monomer copolymerizable with the above monomer in the copolymer is desirably adjusted within the range of 10 to 60% by weight of all the monomers. Of course, two or more of them can be used in combination as needed.

In the present invention, among these other copolymerizable monomers, butyl acrylate and acrylic acid-2 are particularly preferred.
-Ethylhexyl and the like are preferably used from the viewpoint of controlling the copolymerization speed and the glass transition temperature.

The acrylic ester copolymer emulsion of the present invention is a mixture of the above-mentioned monomers as an emulsifier, a chain transfer agent,
It is produced by a method of emulsion copolymerization in an aqueous system in the presence of a polymerization initiator.

It is desirable that the processing liquid containing the above-mentioned specific emulsion as a main component is prepared as an aqueous processing liquid from the viewpoint of coating stability and the like.

In the treatment liquid as described above, a cellulose derivative such as methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, dextrin, oxidized starch, crosslinked starch, esterified starch, and graft copolymer may be used within a range not to impair the desired effects of the present invention. Various water-soluble natural polymers such as starch derivatives such as polymerized starch, synthetic polymers such as polyvinyl alcohol, defoamers, penetrants, wetting agents, lubricants, leveling agents, curing agents, thickeners, A film forming aid, an antistatic agent and the like can be appropriately added.

It is desirable that the solid content concentration of the treatment liquid is adjusted to be in the range of 1 to 50% by weight, preferably 2 to 20% by weight.

On the surface of the surface substrate on which the pressure-sensitive adhesive is not laminated, the treatment solution thus prepared is to be applied or impregnated with the surface substrate with the treatment solution.However, those methods are not particularly limited,
For example, various devices such as an air knife coater, a roll coater, a gate roll coater, a gravure coater, a bar coater, a blade coater, a rod blade coater, and a size press coater are appropriately used. Of course, the coating is not limited to the off-machine coater, and the coating with the on-machine coater installed on the paper machine is preferable because the coating amount is easily applied due to the influence of the paper surface temperature immediately before the coating and the drying property is good. one of.

The adhesion amount of the surface substrate of the processing liquid, even in any of the methods of coating method or impregnation method, respectively dry weight 0.05 to 20 g / m ^2, more preferably about 0.1 to 8 g / m ² of about It is desirable to adjust in the range.

In the pressure-sensitive adhesive sheet of the present invention, as the surface substrate and the release substrate, fiber sheets having a basis weight of about 30 to 300 g / m ² are preferably used.

For the purpose of preventing the release agent from penetrating into the release substrate,
It is desirable to form an undercoat layer.

As a main component of the undercoat layer, for example, a molecular weight of 10
A polymer such as a water-dispersible acrylate copolymer resin having a glass transition temperature of −60 to 0 ° C. containing 2 to 10% by weight of 100 to 10,000 emulsifiers is used. If necessary, the undercoat layer contains various water-soluble natural polymers such as cellulose derivatives and starch derivatives, synthetic polymers such as polyvinyl alcohol, defoamers, penetrants, wetting agents, and anti-blocking agents. , A leveling agent, a curing agent, a thickener, a film forming aid, an antistatic agent, a water-soluble plasticizer, and the like.

The release agent is also not particularly limited, and various silicone compounds, fluorine compounds and the like are applied according to a conventional method.

The pressure-sensitive adhesive sheet of the present invention is applied to a back surface of a release substrate by applying a treatment liquid containing a water-soluble plasticizer as a main component, particularly in order to effectively prevent curling. Jamming due to curling of the toner is extremely efficiently improved, and combined with the provision of a specific polymer on the surface base material to improve the fixability of the toner, the overall suitability of the copying machine is extremely efficiently improved. Things.

Examples of the water-soluble plasticizer used in the present invention include ethylene glycol, glycerin, trimethylolpropane, diethylene glycol, triethylene glycol, dipropylene glycol, pentaerythritol,
Polyhydric alcohols such as sorbitol, sorbitan, and sucrose;
Polyethylene glycols of various degrees of polymerization, polyalkylene glycols such as polypropylene glycol and the like, among which glycerin, trimethylolpropane, diethylene glycol, triethylene glycol,
Dipropylene glycol is more preferably used because of its excellent curl correcting effect. The plasticizer may be used in combination of two or more compounds as necessary.

The treatment liquid in the present invention is prepared by dissolving the water-soluble plasticizer as described above in water, and the solid concentration of the water-soluble plasticizer in the treatment liquid is 1 to 50% by weight, preferably 10% by weight.
It is preferably prepared to be in the range of 3030% by weight.

In addition, in such a treatment solution, various water-soluble natural polymers such as cellulose derivatives and starch derivatives, synthetic polymers such as polyvinyl alcohol, and defoamers within a range not to impair the desired effects of the present invention. , A penetrant, a wetting agent, a lubricant for blocking prevention, a leveling agent, a curing agent, a thickener, a film forming aid, an antistatic agent, a surfactant and the like can be added as appropriate.

The application of the treatment liquid to the surface of the release substrate on which the release agent is not laminated may be performed before or after the release substrate is processed into the pressure-sensitive adhesive sheet.
Although the treatment can be carried out in an optional step such as an adhesive application step and a bonding step, it is desirable from the point of curl correction effect immediately before or immediately after bonding the surface substrate after applying the adhesive.

The degree of treatment on the surface of the release substrate on which the release agent is not laminated is such that the components contained in the treatment liquid are 0.
It is desirable to treat so as to adhere in the range of 1 to 20% by weight, preferably 0.5 to 15% by weight. Further, the treatment liquid can be applied by a known apparatus such as an air knife coater, a roll coater, a gravure coater, and a bar coater.

The method for constructing the pressure-sensitive adhesive sheet of the present invention is carried out according to a conventional method, for example, by applying a solvent-type pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, a hot-melt-type pressure-sensitive adhesive on a release sheet, and drying the pressure-sensitive adhesive if necessary. The pressure-sensitive adhesive layer has a tensile strength (according to JIS K-6301) of 5
When it is not less than Kg / cm ^2, it is one of the preferred embodiments, since when the pressure-sensitive adhesive sheet is die-cut and sheet-cut with a printing machine, adhesion of the pressure-sensitive adhesive to the cutting blade is suppressed.

Then, a surface substrate is bonded on the pressure-sensitive adhesive layer to finish the pressure-sensitive adhesive sheet.When the surface substrate is heat-treated in an oven at 50 to 100 ° C. immediately before bonding the surface substrate,
This is one of the preferred embodiments because a curl correcting effect can be further obtained.

Next, an example of a process for obtaining the pressure-sensitive adhesive sheet of the present invention will be schematically described.

Manufacture of surface base material On a fiber sheet containing recycled pulp, an acrylic ester copolymer emulsion having a specific glass transition temperature obtained by emulsion-copolymerizing the specific monomer used in the present invention as a main component The treatment liquid to be applied is applied or impregnated with an off-machine coater or an on-machine coater, dried, and then subjected to a smoothing treatment with a super calender.

Manufacture of a release substrate provided with an undercoat layer An undercoat layer coating solution is applied and dried on a fiber sheet containing recycled pulp, and is subjected to a smoothing treatment by a super calender.

Production of pressure-sensitive adhesive sheet A release agent is applied on the undercoat layer, dried, a pressure-sensitive adhesive layer is further applied thereon, and dried, and then, the back surface side of the surface substrate is adhered to the pressure-sensitive adhesive layer, Immediately thereafter, a treatment liquid containing the above-described water-soluble plasticizer as a main component is applied to the back surface of the release substrate. In this case, if the surface substrate is heat-treated immediately before bonding the surface substrate, a further curl correcting effect can be expected.

"Examples" Hereinafter, the present invention will be described more specifically with reference to examples, but is not limited thereto.

In addition, the coating amount, the number of copies, the mixing ratio, and the like in the examples are all represented by solid contents (weight) unless otherwise specified.

Example 1 A recycled pulp of 240 ml of freeness (CSF) using newspaper as a raw material was beaten with a double disc refiner to obtain a freeness of 100 ml. Talc was added to a pulp slurry obtained by blending 70 parts of LBKP and 20 parts of NBKP, each of which was beaten to a freeness of 500 ml, and talc was added so that the paper ash content was 6%. 1.4% with respect to After adjusting the pH of this pipe slurry to 4.6 with a sulfuric acid band, papermaking was carried out with a fourdrinier paper machine.
Oxidized starch (trade name: Ace A / Oji Cornstarch Co., Ltd.)
Size press of 1.5 g / m ² in dry weight, dried and processed with a machine calender, basis weight 52 g / m ² , thickness 70 μm, specular reflection type smoothness meter A base paper for a surface substrate having a measured value of 9% (pressurized condition 20 kg / cm ² ) of 9% was obtained.

A 200 ml freeness recycled pulp made from newspaper was beaten with a double disc refiner to a 100 ml freeness. To 40 parts of the recycled pulp obtained in this way, 40 parts of LBKP beaten to a freeness of 500 ml and NBK
Talc was added to the pulp slurry obtained by mixing P20 parts so that the paper ash content was 6%, and rosin size as a sizing agent was added at 1.4% to the absolutely dry pulp.

After adjusting the pH of this pulp slurry to 4.6 with a sulfuric acid band, papermaking was carried out with a fourdrinier paper machine, and an aqueous solution of oxidized starch (trade name; Ace C / Oji Cornstarch Co., Ltd.) at 1.5 g / m
^The size is pressed to ² and processed with a machine calender. The basis weight is 50 g / m ² , the thickness is 65 μm, and the value measured with a regular reflection type smoothness meter (pressing condition: 20 kg / cm ² ) is 15%. Was obtained.

Next, the treatment liquid A having the following composition was applied to the surface of the base paper for base material by a bar coater so that the dry application amount was 1.0 g / m ² , dried and smoothed by a super calender, and the surface base was treated. Wood was obtained.

Preparation of treatment liquid A Emulsion monomer mixture consisting of 260 g of methyl methacrylate, 40 g of butyl acrylate, 88 g of 2-ethylhexyl acrylate, 12 g of acrylic acid, 7 g of sodium polyoxyethylene nonylphenyl ether sulfate emulsifier, and 170 g of ion-exchanged water Liquid [I] was prepared.

Next, a stirrer, cooler, dropping funnel, nitrogen suction pipe,
Ion-exchanged water in a two four-necked flask with a thermometer
240 g and 2 g of sodium polyoxyethylene nonylphenyl ether sulfate emulsifier, 0.8 g of potassium persulfate were charged,
After the temperature was raised to 70 ° C. while purging with nitrogen, the above-mentioned emulsified monomer mixture [I] was dropped therein for 2 hours to carry out polymerization. After completion of the dropwise addition, the mixture was aged at 70 ° C. for 2 hours to complete the polymerization. The glass transition temperature of the obtained acrylate copolymer emulsion was 27 ° C.

Next, this acrylate copolymer emulsion
An aqueous treatment liquid (concentration 10%) containing 97 parts, 2 parts of a wax emulsion, and 1 part of an antifoaming agent was prepared.

Production of Release Sheet A terpolymer of butyl acrylate-acrylonitrile-acrylic acid containing 2% by weight of an emulsifier having a molecular weight of 2500 [trade name: Licabond ET-L-924-1 (glass transition temperature: -14 ° C.) / Chuo Rika Kogyo Co., Ltd.] A butyl acrylate-acrylonitrile-methyl methacrylate-acrylic acid quaternary copolymer containing 100 parts and 2% of an emulsifier having a molecular weight of 2500 [trade name: Ricabond ET-L-924-] 2 (glass transition temperature: 48 ° C.) / Chuo Rika Kogyo Co., Ltd.] 20 parts of an aqueous copolymer mixed with 10 parts of polyvinyl alcohol,
It was added to 1 part of glycerin, 2 parts of colloidal silica and 0.1 part of an antifoaming agent to prepare an aqueous treatment liquid for an undercoat layer having a concentration of 40%.

This aqueous treatment liquid for undercoat layer was applied onto the base paper for release substrate by a rod blade coater so as to have a dry coating amount of 4 g / m ^2, and dried to obtain a release substrate having an undercoat layer.

On this undercoat layer, a silicone release agent (trade name: SRX-21)
A 1% toluene solution of 1 / Toray Silicone Co., Ltd.) was applied and dried with a bar coater so that the dry coating amount was 1 g / m ² to obtain a release sheet.

Manufacture of pressure-sensitive adhesive sheet An acrylic emulsion pressure-sensitive adhesive [trade name: Nicazole L-122 (tensile strength: 2.
5 g / cm ² ) / Nippon Carbide Co., Ltd.] was applied and dried using a reverse roll coater so that the dry coating amount was 20 g / m ² .

Then, the surface (back surface) of the surface substrate on which the treatment liquid A is not applied is superimposed on the pressure-sensitive adhesive layer and bonded by a press roll. Then, the treatment liquid B having the following composition is dried and applied to the back surface of the release sheet. Was applied with a roll coater and dried so as to be 1.0 g / m ² to produce an adhesive sheet.

Preparation of treatment liquid B An aqueous treatment liquid (concentration: 22.9% by weight) containing glycerin (22 parts) and sodium hydrogen carbonate (0.9 parts) was prepared.

Example 2 A 420-ml freeness recycled pulp made from upper white was beaten with a double disc refiner to give a 300-ml freeness. To a pulp slurry obtained by blending 90 parts of the recycled pulp with 10 parts of NBKP beaten to a freeness of 500 ml, talc was added so that the paper ash content was 6%, and the rosin size was further changed as a sizing agent to the absolutely dried pulp. 1.4%.

After adjusting the pH of the pulp slurry to 4.6 with a sulfuric acid band, papermaking was performed with a fourdrinier paper machine, and an aqueous solution of oxidized starch (trade name: Ace A) was size-pressed to a solid content of 1.5 g / m ^2. Metal roll and elastic roll (Shore D hardness 87)
Processed by an on-machine calender consisting of
A base paper for a surface substrate having a basis weight of 40 g / m ² , a thickness of 50 μm, and a value measured by a regular reflection type smoothness meter (pressing conditions of 20 kg / cm ² ) of 16% was obtained.

The processing liquid A of Example 1 was applied to the base paper using an on-machine champlex coater so that the dry coating amount was 2 g / m ^2, and then dried and smoothed with a super calender to obtain a surface substrate. Produced an adhesive sheet in the same manner as in Example 1.

Example 3 A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the surface substrate was heat-treated in an oven at 80 ° C. and bonded onto the pressure-sensitive adhesive layer immediately before bonding the surface substrate. .

Example 4 A 200 ml freeness recycled pulp made from newspaper was beaten with a double disc refiner to a 150 ml freeness. Each 10 parts of the recycled pulp has a freeness
Heavy calcium carbonate (trade name: Softon 1200, manufactured by Bihoku Powder Co., Ltd.) was added to a pulp slurry obtained by mixing 70 parts of LBKP and 20 parts of NBKP beaten to 500 ml so that the paper ash content was 6%. And then add a sulfate band to the dried pulp.
5% and a cationic starch (trade name: CATO-F / Oji National Co., Ltd.) were added to the dry pulp at 0.5%, and an alkyl ketene dimer (trade name: SPK 9) was used as a neutral sizing agent.
0 / Arakawa Chemical Co., Ltd.) was added to the absolutely dry pulp, and then the paper was made with a fourdrinier paper machine, and an aqueous solution of oxidized starch (trade name: Ace A) having a solid content of 1.5 g / m ^{2 was used.} Press the metal roll and elastic roll (Shore D hardness 91)
Processed by an on-machine calender consisting of
A base paper for a surface substrate having a basis weight of 64 g / m ² , a thickness of 75 μm, and a value measured with a regular reflection type smoothness meter (pressing conditions of 20 kg / cm ² ) of 15% was obtained.

On the surface of this base paper, instead of treatment liquid A, treatment liquid C having the following composition was applied and dried so as to have a dry coating amount of 1.2 g / m ^2, and smoothed by a super calender to obtain a surface substrate. Except for the above, an adhesive sheet was produced in the same manner as in Example 1.

Preparation of Treatment Liquid C An acrylate copolymer emulsion was obtained in the same manner as in Treatment Liquid A of Example 1, except that a monomer mixture of 300 g of methyl methacrylate, 80 g of butyl acrylate, and 20 g of acrylic acid was used. (Glass transition temperature: 56 ° C.) An aqueous treatment liquid (concentration: 10%) containing 90 parts of this acrylate copolymer emulsion, 8 parts of colloidal silica, and 2 parts of an antifoaming agent was prepared.

Example 5 Instead of the treatment liquid A, a treatment liquid D having the following composition was applied to the surface of the base paper for surface base material having a basis weight of 52 g / m ² and a thickness of 70 μm in the same manner as in the example 1 to a dry coating amount of 1.2 g / m ² . A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that a surface substrate was obtained by coating and drying as described above and performing a smoothing treatment with a super calender.

Preparation of treatment liquid D Same as treatment liquid A of Example 1 except that a monomer mixture of 280 g of styrene, 68 g of methyl methacrylate, 40 g of 2-ethylhexyl acrylate, and 12 g of acrylic acid was used. A combined emulsion (glass transition temperature: 76 ° C.) was obtained.

An aqueous treatment liquid (concentration: 15%) containing 95 parts of the acrylate copolymer emulsion thus obtained, 4 parts of a wax emulsion, and 1 part of an antifoaming agent was prepared.

Example 6 A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the treatment liquid E having the following composition was applied instead of the treatment liquid A to the surface of the surface substrate.

Preparation of treatment liquid E Acrylic ester was prepared in the same manner as treatment liquid A of Example 1 except that a monomer mixture of 290 g of methyl methacrylate, 60 g of butyl acrylate, 30 g of 2-ethylhexyl acrylate, and 20 g of acrylic acid was used. A copolymer emulsion (glass transition temperature: 49 ° C.) was obtained. Aqueous treatment liquid (concentration: 8%) containing 97 parts of acrylate copolymer emulsion thus obtained, 2 parts of wax emulsion, and 1 part of defoamer
Was prepared.

Example 7 A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the treatment liquid F having the following composition was applied instead of the treatment liquid A to the surface of the surface substrate.

Preparation of treatment liquid F Acrylic ester was prepared in the same manner as treatment liquid A of Example 1 except that a monomer mixture of 360 g of methyl methacrylate, 10 g of butyl acrylate, 10 g of 2-ethylhexyl acrylate, and 20 g of acrylic acid was used. A copolymer emulsion (glass transition temperature: 91 ° C.) was obtained. Aqueous treatment liquid (concentration: 8%) containing 97 parts of acrylate copolymer emulsion thus obtained, 2 parts of wax emulsion, and 1 part of defoamer
Was prepared.

Example 8 Example 8 was the same as Example 1 except that the adhesive was an acrylic emulsion adhesive (trade name: Olivine BPW-5082-2 (tensile strength: 8.0 kg / cm ² ) / Toyo Ink Mfg. Co., Ltd.). An adhesive sheet was produced in the same manner.

Example 9 In the same manner as in Example 1 except that the adhesive was an acrylic emulsion adhesive [trade name: Nicazole TS-1226 (tensile strength: 10.5 kg / cm ² ) / manufactured by Nippon Carbide Co., Ltd.] An adhesive sheet was manufactured.

Example 10 A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that high-quality paper having a basis weight of 52 g / m ² and a thickness of 70 μm and containing no waste paper was used as a surface substrate.

Example 11 A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that a high-quality paper having a basis weight of 50 g / m ² and a thickness of 65 μm and containing no waste paper was used as a release substrate.

Comparative Example 1 An adhesive sheet was produced in the same manner as in Example 1 except that the treatment liquid A was not applied.

Comparative Example 2 In place of treating solution A, treating solution G having the following composition was applied on a surface of a high-quality paper having a basis weight of 52 g / m ² and a thickness of 70 μm using a bar coater so as to have a dry application amount of 0.7 g / m ^2. did.

Preparation of treatment liquid G Acrylic ester copolymer emulsion [trade name: A
E-816 (glass transition temperature: -48 ° C) / manufactured by Nippon Synthetic Rubber Co., Ltd.] 80 parts, a wax emulsion 10 parts, colloidal silica 8 parts, an aqueous treatment liquid containing a defoaming agent 2 parts (concentration 8
%) Was prepared.

In addition, when the winding was rewound to super-calender the surface substrate, remarkable blocking occurred on the front and back surfaces, and the surface of the surface substrate was completely destroyed. Therefore, a pressure-sensitive adhesive sheet could not be produced.

Comparative Example 3 A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the treatment liquid H having the following composition was applied and dried on the surface of the high-quality paper instead of the treatment liquid A.

Preparation of treatment liquid H Styrene 130 g, butyl acrylate 250 g, acrylic acid 20
An acrylic ester copolymer emulsion (glass transition temperature: −15 ° C.) was obtained in the same manner as in the treatment liquid A of Example 1 except that the monomer mixture of g was used. An aqueous treatment liquid (concentration: 8%) containing 80 parts of the acrylate copolymer emulsion thus obtained, 10 parts of a wax emulsion, 8 parts of colloidal silica, and 2 parts of an antifoaming agent was prepared.

In addition, when the winding was rewound to super-calender the surface substrate, a slight blocking occurred on the front and back surfaces, so that the surface of the surface substrate was partially destroyed.

Comparative Example 4 Treatment liquid A was applied on the surface of a high-quality paper having a basis weight of 64 g / m ² and a thickness of 75 μm.
Instead of a processing solution I having the following composition, the coating weight of which is 1.0 g / m ²
Was applied and dried with an air knife coater and subjected to a super calender treatment to obtain a surface substrate.

Preparation of Treatment Solution I 97 parts of styrene / maleic anhydride copolymer (trade name; script set 520 (glass transition temperature: 130 ° C.) / Monsanto Co., Ltd.), 2 parts of colloidal silica, and 1 part of defoamer An aqueous coating solution (concentration: 10%) was prepared.

Next, the same acrylic emulsion pressure-sensitive adhesive as that of Example 1 was applied to the release agent-coated surface of the same release sheet as that of Example 1 using a reverse roll coater so that the dry application amount was 22 g / m ^2, and the procedure was the same. A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1.

Comparative Example 5 A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that water was applied to the back surface of the release sheet instead of the treatment liquid B with a roll coater so as to be 4 cc / m ² and dried.

The curls of the 12 types of pressure-sensitive adhesive sheets thus obtained, the jamming state when passing the paper through a copying machine, and the toner fixability were evaluated and the results are shown in Table 1.

[Curl evaluation]

Evaluation was made according to J.TAPPI pulp test method No. 16-77.

 Curl degree = 100 / curl radius (cm) TS indicates normal curl (curl toward the surface substrate side), and WS indicates reverse curl (curl toward the release substrate side).

[Jamming state when passing paper]

 ；: Jamming is not recognized at all.

Δ: Jamming may occur, but at a level that does not cause any practical problem.

×: remarkable jamming occurs, and there is a practical problem.

[Toner fixing property]

After copying the original with a copying machine (trade name; SF-8100 / manufactured by Sharp Corporation), the toner in the printing portion was shaved ten times with a razor, and the toner fixability was evaluated.

；: The toner hardly falls off.

Δ: The toner slightly dropped, but there was no practical problem.

X: The toner was remarkably dropped.

In the table, "Normal humidity" means humidity control for 7 hours in an environment of 28 ° C and 60% RH, and "high humidity" means 25 ° C and 90% RH.
The results of measurement after humidity control for 7 hours in the above environment were shown.

The term "blocking" in Table 1 refers to a phenomenon in which the front and back surfaces of the front substrate adhere to each other when the winding is rewound to supercalender the front substrate.

[Cut suitability]

After 100 sheets of adhesive sheet cut to 20cm in length and 15cm in width are stacked and cut continuously 20 times in the width direction with a guillotine tester (trade name: CM-450 / Rokugo Seisakusho Co., Ltd.) The amount (unit: mg) of the adhesive adhered to the guillotine blade was measured.

"Effects" As is clear from the results in Table 1, the pressure-sensitive adhesive sheet of the present invention has no curl and no jamming during paper passing in a copying machine.
Further, the fixing property of the toner was extremely excellent.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-135474 (JP, A) JP-A-63-75199 (JP, A) JP-A-59-98186 (JP, A) 199605 (JP, A) JP-A-48-14748 (JP, A) JP-A-51-136908 (JP, A) JP-A-50-25087 (JP, A) (58) Fields investigated (Int. ⁶ , DB name) C09J 7/00-7/04 B32B 29/06

Claims (6)

(57) [Claims] 1. A pressure-sensitive adhesive sheet comprising a release substrate, a release agent, a pressure-sensitive adhesive and a surface base material laminated in this order, wherein, as the release base material and / or the surface substrate sheet, waste paper is contained in a pulp composition constituting the sheet. The recycled pulp as a raw material contains 10% by weight or more, and the smoothness of the surface of the sheet containing the recycled pulp is 8% or more as measured by a regular reflection type smoothness meter under a pressure condition of 20 kg / cm ^2. A certain base paper is used, and on the surface of the surface base material on which the adhesive is not laminated, (i) an ethylenically unsaturated carboxylic acid-containing monomer (ii) a homopolymer having a glass transition temperature of 50 ° C. or higher An unsaturated bond-containing monomer and (iii) another monomer copolymerizable with these monomers (provided that at least one of the monomers (ii) and (iii) is an acrylate monomer) The glass transition temperature of the emulsion copolymerized from 0 to 100 A treatment liquid mainly containing an acrylic ester copolymer emulsion is applied or a surface base material is impregnated with the treatment liquid, and a water-soluble plasticizer is mainly contained on the surface of the release substrate on which the release agent is not laminated. A pressure-sensitive adhesive sheet, characterized by being coated with a treatment liquid described below. 2. The recycled pulp is subjected to beating treatment before papermaking to obtain Canadian Standard Freeness.
The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive sheet is pulp reduced in a range of 30 to 150 ml. 3. The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive has a tensile strength of 5 kg / cm ² or more as measured according to JIS K-6301. 4. The pressure-sensitive adhesive sheet according to claim 1, wherein an undercoat layer containing a polymer compound as a main component is provided between the release substrate and the release agent. 5. The pressure-sensitive adhesive sheet according to claim 1, wherein the treatment liquid for the surface substrate is applied or impregnated with an on-machine coating machine. 6. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive is applied to a release sheet provided with a release agent on a release substrate, dried, and then coated on a surface substrate. A method for producing a pressure-sensitive adhesive sheet, wherein the surface base material is heat-treated at 50 to 100 ° C. immediately before bonding.