JP2003336024A - Aqueous emulsion-type self-adhesive and self-adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous emulsion-type self-adhesive which is free from an alkylphenol group-containing compound, an endocrine disruptor, causes no streak marks, cissings and the like in the self-adhesive layer when it is applied on a release sheet and ensures excellent productivity, and a self-adhesive sheet. <P>SOLUTION: The aqueous emulsion-type self-adhesive comprises an aqueous emulsion comprising an unsaturated monomer (A) comprising an alkyl (meth) acrylate bearing a 1-14C alkyl group, a carboxy group-containing unsaturated monomer (B), and a surfactant (C) of a specific structure, where (a) the average particle size of particles constituting the aqueous emulsion is 0.1-1 μm, (b) the solid content is at least 50 wt.%, (c) the viscosity measured by the B-type viscometer at 23°C and 60 rpm is at least 50 mPas but less than 2,000 mPas, and (d) the tetrahydrofuran insoluble content of a dry film formed from the aqueous emulsion is 20-80 wt.%. The self-adhesive sheet is obtained by applying the aqueous emulsion on a release sheet. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aqueous emulsion-type pressure-sensitive adhesive and a pressure-sensitive adhesive sheet. More specifically, the aqueous emulsion-type pressure-sensitive adhesive does not contain an alkylphenol group-containing compound that is an endocrine disrupting substance, The present invention relates to an aqueous emulsion type pressure-sensitive adhesive and a pressure-sensitive adhesive sheet, which are free from streaks, cissing, streaks, drips and the like when the aqueous emulsion-type pressure-sensitive adhesive is applied onto a release sheet and have excellent productivity.

[0002]

2. Description of the Related Art Conventionally, adhesive sheets have been processed into labels, stickers, stickers, patches, overlaminate films, protective sheets, etc. for the purpose of marking identification, decoration, masking masking, sealing seals, information transmission, disaster prevention safety, etc. Widely used for commercial, industrial, office, household, etc. The pressure-sensitive adhesive sheet generally has a pressure-sensitive adhesive layer formed between a surface base material and a release sheet. Usually, paper, film, metal foil or the like is used for the surface substrate, and release sheet is coated with a silicone compound release agent on glassine paper, clay coated paper, film laminated paper, polyester film, polyethylene film, etc. Things are used. As the pressure-sensitive adhesive, there are a solvent type, an aqueous emulsion type, a hot melt type and the like, and resin type ones such as acrylic type, rubber type, urethane type and silicon type are used. Since the application and properties of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet are largely different, the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer is an important factor for characterizing the pressure-sensitive adhesive sheet.

At present, considering the global environment, the working environment, etc.,
Aqueous emulsion type pressure-sensitive adhesives are widely used and used for many pressure-sensitive adhesive sheets because of low cost and almost no organic solvent. Further, recently, as an environmental problem, an endocrine disrupting substance caused by a surfactant containing an alkylphenol group has been particularly cited as a problem, and its countermeasure is demanded. On the other hand, in order to improve productivity from the economical viewpoint, there is a demand for increasing the coating speed of the pressure-sensitive adhesive and a demand for reducing the coating amount of the pressure-sensitive adhesive in the production of the pressure-sensitive adhesive sheet. Attempts to increase the coating speed of the water-based emulsion pressure-sensitive adhesive have been attempted from both the viewpoint of improving the coating equipment and improving the water-based emulsion-type pressure-sensitive adhesive. As a coating device, in addition to the conventionally well-known reverse roll coater, air knife coater, knife coater, comma coater, etc., a slot die coater and a lip coater for pressurizing and pressing an adhesive to apply it to a substrate. Fountain coaters such as curtain die coaters have been developed, and it has become possible to increase the coating speed considerably.
On the other hand, as an attempt to improve the water-based emulsion type pressure-sensitive adhesive, a method of lowering the low shear viscosity is indispensable in order to improve suitability for high-speed coating, but when the low shear viscosity is lowered, it is applied to a release sheet. Occasionally, cissing and streaks occur, liquid sagging, and problems that the adhesive layer spreads too much. Therefore, conventionally, it has been necessary to increase the low shear viscosity of the aqueous emulsion type pressure-sensitive adhesive. However, conventionally, when the coating speed of the water-based emulsion type adhesive is increased, the low shear viscosity is too high, and therefore it is the current situation that it is insufficient to produce an adhesive sheet having a clean coated surface of the adhesive. . Especially water-based emulsion type adhesive
When a pressure-sensitive adhesive sheet is manufactured by coating at a speed of 00 m / min or more, or when a pressure-sensitive adhesive sheet such as an overlaminate film that is required to be transparent is manufactured by coating at a speed of 100 m / min or more The finish of the agent coated surface is poor.

[0004]

Accordingly, an object of the present invention is to coat an aqueous emulsion type pressure-sensitive adhesive on a release sheet without containing an alkylphenol group-containing compound which is an endocrine disrupting substance in the aqueous emulsion type pressure-sensitive adhesive. It is an object of the present invention to provide an aqueous emulsion-type pressure-sensitive adhesive, a pressure-sensitive adhesive sheet, and a method for producing the same, which are free from streaks, cissing, streaks, dripping, etc. in the pressure-sensitive adhesive layer and have excellent productivity.

[0005]

Therefore, as a result of earnest research for solving the above problems, the present inventors have found that a dry film of tetrahydrofuran formed from a specific range of particle diameter, solid content, low shear viscosity and aqueous emulsion. The inventors have found that an aqueous emulsion-type pressure-sensitive adhesive having an insoluble content and containing the following unsaturated monomers and a surfactant can solve the above problems, and completed the present invention.

That is, the present invention provides an unsaturated monomer (A) composed of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 14 carbon atoms, a carboxyl group-containing unsaturated monomer (B), and the following: An aqueous emulsion pressure-sensitive adhesive comprising an aqueous emulsion containing at least one surfactant (C) represented by formulas (1) to (26), comprising:
The average particle size of the particles constituting the aqueous emulsion is 0.
1 to 1 μm, (b) the solid content is 50% by weight or more, (c) the viscosity of the B-type viscometer at 23 ° C. and 60 rpm is 50 mPa · s or more and less than 2000 mPa · s, and (d) The present invention provides an aqueous emulsion-type pressure-sensitive adhesive characterized in that a dry film formed from the aqueous emulsion has a tetrahydrofuran insoluble content of 20 to 80% by weight.

[0007]

[Chemical 5]

[0008]

[Chemical 6]

[0009]

[Chemical 7]

[0010]

[Chemical 8]

(In the above formula, R is an alkyl group, M is an ammonium salt or a metal salt, and AO is ethylene oxide (E
O), alkylene oxide containing propylene oxide (PO), ph is a distyrenated phenyl group, and n
Is an integer of 0 to 50, m is an integer of 0 to 50) Further, in the present invention, the unsaturated monomer (A) is 85 to 99 with respect to the entire components (A), (B) and (C). 0.8% by weight, the carboxyl group-containing unsaturated monomer (B) is 0.1 to 5% by weight, and the surfactant (C) is 0.1 to 10% by weight. The agent is provided. The present invention also provides a pressure-sensitive adhesive sheet obtained by applying the above-mentioned aqueous emulsion-type pressure-sensitive adhesive on a release sheet.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. The carbon number of the alkyl group used in the present invention is 1 to 1
The unsaturated monomer (A) composed of the (meth) acrylic acid alkyl ester of 4 is methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n- Acrylic acid esters such as octyl acrylate, isooctyl acrylate, nonyl acrylate; methacrylic acid esters such as methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, and the like. More than one seed is used. When the number of carbon atoms in the alkyl group is 15 or more, the versatility of the unsaturated monomer is impaired and the resulting aqueous emulsion is expensive, which is not preferable. The unsaturated monomer (A) is preferably contained in an amount of 85 to 99.8% by weight based on the total amount of the components (A), (B) and (C). 8
If it is less than 5% by weight, the viscosity of the obtained aqueous emulsion increases, which is not preferable, and if it exceeds 99.8% by weight, the polymerization stability is deteriorated, which is not preferable.

As the carboxyl group-containing unsaturated monomer (B) used in the present invention, acrylic acid, methacrylic acid,
Examples thereof include various carboxylic acid monomers such as maleic anhydride, itaconic acid, β-carboxyethyl acrylate, and 2- (meth) acryloxyethyl succinic acid. Among them, acrylic acid and methacrylic acid are preferable. The carboxyl group-containing unsaturated monomer (B) is preferably contained in an amount of 0.1 to 5% by weight based on the total amount of the components (A), (B) and (C). 0.
If it is less than 1% by weight, sufficient adhesive strength to various substrates, adhesive strength to wet surface, adhesive strength at low temperature, etc. cannot be expressed, and if it exceeds 5% by weight, polymerization stability becomes poor. Not preferable. It is preferably 0.2 to 4% by weight.

The surfactant (C) used in the present invention is at least one kind represented by the above formulas (1) to (26). In the above formula, R is, for example, an alkyl group having 10 to 30 carbon atoms, M is an ammonium salt or a metal salt such as potassium or sodium, AO is an alkylene oxide containing ethylene oxide (EO) or propylene oxide (PO), and ph is Is a distyrenated phenyl group, n is 0 to 5
The integer of 0 and m have shown the integer of 0-50. As the surfactant (C), various known surfactants can be used. For example, as the surfactant of formula (1), there are Aqualon KH-05, KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) and the like. As the surfactant of formula (2),
For example, there is Eleminor RS-30 (Sanyo Kasei Co., Ltd.) and the like. Examples of the surfactant of the formula (3) include Eleminol JS-2 (Sanyo Kasei Co., Ltd.). As the surfactant of the formula (4), for example, Latemur S-1
80A, S-180 (Kao Corporation) and the like. Formula (5)
Examples of the surfactant include Emulsogen R series (Clariant Japan Co., Ltd.) and the like. Formula (6)
Examples of the surfactant include Adecaria Soap ER series (Asahi Denka Co., Ltd.) and the like. Examples of the surfactant of the formula (7) include Adecaria Soap SR series (Asahi Denka Kogyo KK). As the surfactant of formula (8), for example, Emulgen 100 series, 40
0 series, 1100 series (Kao Corporation), Neugen ET series, YX series, DKS-NL series (Daiichi Kogyo Seiyaku Co., Ltd.), New Call 1000
System, 1100 system, 1200 system, 1300 system, 1600
System, 1800 system (Nippon Emulsifier Co., Ltd.) and the like. As the surfactant of the formula (9), for example, Emar D-3
-D, Ramtel E-118B, E-150, Rebenol WX (Kao Corp.), Hitenol 08E, 18E, L
A series (Daiichi Kogyo Seiyaku Co., Ltd.), Newcol RA
-9600 series, 1105SN, 1305SN (Nippon Emulsifier Co., Ltd.) and the like. Examples of the surfactant of the formula (10) include Emar 0, 10 (Kao Corporation), Monogen Y-500 (Daiichi Kogyo Seiyaku Co., Ltd.) and the like. Examples of the surfactant of the formula (11) include Perex O.
TP (Kao Corporation), Neocor SW-C (Daiichi Kogyo Seiyaku Co., Ltd.) and the like. Examples of the surfactant of the formula (12) include Newcol 293 and RA-544 (Nippon Emulsifier Co., Ltd.). Examples of the surfactant of the formula (13) include NS soap, KS soap, OS soap (Kao Corporation) and the like. Examples of the surfactant of the formula (14) include Latemur ASK (Kao Corporation). Examples of the surfactant of formula (15) include Antox MS-60 (Nippon Emulsifier Co., Ltd.). Examples of the surfactant of the formula (16) include Neugen EA
-167, EA-177 (Daiichi Kogyo Seiyaku Co., Ltd.), Newcol 700 series, 2600 series, B series (Nippon Emulsifier Co., Ltd.) and the like. As the surfactant of formula (17),
For example, Hitenol NF-13, NF-17 (Daiichi Kogyo Seiyaku Co., Ltd.), Newcol 700 series SF, 700 series SN, B series SN (Nippon Emulsifier Co., Ltd.) and the like are available. Expression (1
Examples of the surfactant 8) include Neoperex series (Kao Corporation), Neogen RK (Daiichi Kogyo Seiyaku Co., Ltd.) and the like. As the surfactant of formula (19),
For example, there is Latemul PS (Kao Corporation). Formula (2
Examples of the surfactant of 0) include Perex SS-
L, SS-H (Kao Corporation), Newcol 271 series (Nippon Emulsifier Co., Ltd.) and the like. Examples of the surfactant of formula (21) include Newcol 20, 25 (Nippon Emulsifier Co., Ltd.). Examples of the surfactant of formula (22) include Newcol 1500 series (Nippon Emulsifier Co., Ltd.). As the surfactant of formula (23),
For example, there is Newcol 1500 series SF (Nippon Emulsifier Co., Ltd.) and the like. As the surfactant of formula (24),
For example, Newcol 180T (Nippon Emulsifier Co., Ltd.) is available. Examples of the surfactant of the formula (25) include ADEKA REASOAP PP-70 (Asahi Denka Kogyo KK). Examples of the surfactant represented by the formula (26) include ADEKA REASOAP PPE-710 (Asahi Denka Kogyo KK).

Surfactant (C) of formula (1) to formula (26)
Is used in an amount of 0.1 to 10% by weight, preferably 0.2 to 7% by weight, based on the entire components (A), (B) and (C).
Is good. If it is less than 0.1% by weight, an aqueous emulsion with good stability cannot be prepared, and 10% by weight
If it exceeds, the tackiness as an adhesive and the adhesiveness to an adherend are impaired, which is not preferable.

In the present invention, other copolymerizable monomers other than the above components can be used. Examples thereof include vinyl compounds such as vinyl acetate, vinyl propionate, acrylonitrile, methacrylonitrile, styrene and vinyltoluene; amide compounds such as acrylamide, methacrylamide, diacetone acrylamide; N-
N-alkylol derivatives such as methylol acrylamide and N-methylol methacrylamide; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate and hydroxylpropyl acrylate; epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate Body; polyfunctional unsaturated monomer such as civinylbenzene, diallyl phthalate, diethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate; vinyltriethoxysilane, vinyltri (2-methoxyethoxy) silane, γ-glycidoxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, and other vinylalkoxysilanes; glycidoxyalkoxysilanes The body etc. are mentioned. These other copolymerizable monomers include (A), (B) and (C)
It is desirable to add it in a ratio of 0 to 20% by weight with respect to the entire components.

In the present invention, it is of course possible to use a chain transfer agent. Examples of the chain transfer agent include alcohols such as methanol, ethanol and isopropyl alcohol, mercaptans such as dodecyl mercaptan and 2-ethylhexyl thioglycolate, and the like, and these can be used alone or in combination.

In the preparation of the aqueous emulsion of the present invention, the polymerization conditions are not particularly limited, but for example, 30
It can be performed at a temperature of ~ 85 ° C. Examples of the polymerization initiator used at this time include peroxides such as tertiary butyl hydroperoxide, hydrogen peroxide, benzoyl peroxide, cumene hydroperoxide, and persulfates such as potassium persulfate and ammonium persulfate. These can be used alone or in combination. Further, a reducing agent can be used if necessary. Examples thereof include sodium hydrogen sulfite, sodium sulfite, ascorbic acid, nitric acid and the like.

Further, in the aqueous emulsion of the present invention, ammonia, various amines, various defoaming agents, preservatives,
It goes without saying that various additives such as a leveling agent, a cross-linking agent, a tackifier, a filler such as titanium oxide and calcium carbonate may be added within a range that does not impair the effects of the present invention.

The average particle size of the particles constituting the aqueous emulsion in the present invention is 0.1 to 1 μm, preferably 0.2 to 0.8 μm. Average particle size is 0.1μ
When it is less than m, the viscosity and the structural viscosity are high and the leveling property is deteriorated, so that the finish of the adhesive coated surface is deteriorated. On the other hand, when the average particle diameter exceeds 1 μm, the aqueous emulsion particles settle down with time, and the transparency of the pressure-sensitive adhesive layer deteriorates.

The solid content of the aqueous emulsion of the present invention must be 50% by weight or more. When the solid content is less than 50% by weight, the drying speed is slow and it is not practical and is not preferable.

The viscosity of the aqueous emulsion in the present invention must be 50 mPa · s or more and less than 2000 mPa · s as measured by a B-type viscometer at 23 ° C. and 60 rpm. When the viscosity is less than 50 mPa · s, when the coating speed of the pressure-sensitive adhesive is set to a high speed (100 m / min or more), cissing or tingling occurs on the entire surface of the pressure-sensitive adhesive coated on the release sheet. When the coating speed is 2000 mPa · s or more, a rib pattern is generated on the coated surface and fine bubble defects due to air entrainment occur when the coating speed is high (100 m / min or more). Particularly preferable range of viscosity is 200 to 1
It is 500 mPa · s.

Further, the insoluble content of tetrahydrofuran in the dry film formed from the aqueous emulsion in the present invention must be 20 to 80% by weight. When the tetrahydrofuran insoluble matter in the dry film is less than 20% by weight,
The holding power at 40 ° C decreases. On the other hand, if it exceeds 80% by weight, the adhesive strength to various substrates, particularly the adhesive strength to polyolefins such as PE and PP decreases, which is not preferable. In order to control the insoluble content of tetrahydrofuran in the dry film formed from the aqueous emulsion of the present invention within a predetermined range,
The combination of the monomer components, the polymerization temperature, the type and amount of the polymerization initiator, the type and amount of the chain transfer agent, the combined use of the crosslinkable monomer and the like may be appropriately combined.

The base material used in the present invention is not particularly limited, and conventionally known materials can be appropriately selected. For example, various papers, films, metal foils, etc. may be mentioned.

The pressure-sensitive adhesive comprising the aqueous emulsion of the present invention can be applied at high speed on a release sheet (for example, at a speed of 100 m / min or more). As a coating device for that, a reverse roll coater, an air knife coater,
Knife coater, comma coater, reverse gravure coater, slot die coater, lip coater, curtain die coater, etc. can be mentioned, but it is a fountain coater suitable for high-speed coating where pressure is applied to the adhesive to apply it to the substrate. Die coaters, lip coaters, curtain die coaters, etc. are also desirable. The coating amount of the pressure-sensitive adhesive of the present invention is not particularly limited, but is, for example, 10 to 30.
g / m ² . According to the present invention, a pressure-sensitive adhesive sheet which is free from streaks, cissing, blemishes, liquid sagging, etc. in the pressure-sensitive adhesive layer even when applied at a normal speed or a low speed of less than 100 m / min and has excellent productivity. Of course,

The release sheet used is not particularly limited, and conventionally known materials can be appropriately selected. For example, glassine paper, clay coated paper, film laminated paper, polyester film, polyethylene film and the like coated with a silicone compound release agent can be used.

[0027]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples,% and parts are based on weight. (Example 1) 150 parts of ion-exchanged water was charged in a container having a stirrer, a thermometer, a reflux condenser, and a dropping funnel.
The temperature was raised to ° C. On the other hand, 200 parts of ion-exchanged water, 285 parts of butyl acrylate, 200 parts of 2-ethylhexyl acrylate, 15 parts of acrylic acid, Eleminol JS-2
Twenty-five parts (40% of active ingredient, Sanyo Kasei Co., Ltd., surfactant of the above formula (3)) were emulsified with a homomixer to prepare a mixed emulsion (A). 10 parts of a 3% potassium persulfate aqueous solution was charged into the above container to start emulsion polymerization. The polymerization was carried out by dropping 30 parts of the mixed emulsion (A) and a 3% potassium persulfate aqueous solution into the container over 3 hours. During this time, the inside of the container was kept at 80 ° C. After completion of dropping, the mixture was kept at 80 ° C. for 1 hour for aging. After that, cooling is started, and after cooling to 30 ° C., ammonia water is added to adjust the pH to 8
Adjusted to. The viscosity of the obtained aqueous emulsion is 40
0 mPa · s (B-type viscometer, measured at 60 rpm. The same applies hereinafter), solid content is 55.9%, and average particle size is 0.5.
It was 1 μm.

(Example 2) Polymerization was carried out in the same manner as in Example 1 except that 40 parts of Eleminol JS-2 (active ingredient 40%) was used as the surfactant.
The viscosity of the obtained aqueous emulsion is 1550 mPa.
s, solid content is 55.6%, average particle size is 0.29μ
It was m.

Example 3 In Example 1, 25 parts of Eleminol JS-2 (active ingredient 40%) and Emulgen 1118S-70 (active ingredient 70%, Kao Corporation, the above-mentioned formula (8)) were used as the surfactant. Polymerization was carried out in the same manner as in Example 1 except that the surfactant was changed to 7.1 parts. The obtained aqueous emulsion had a viscosity of 1000 mPa · s, a solid content of 56.0%, and an average particle diameter of 0.38 μm.

(Example 4) In Example 1, the surfactant was used as Latemur S-180A (active ingredient 40%, Kao).
Polymerization was performed in the same manner as in Example 1 except that the amount of the surfactant (formula 4) was changed to 25 parts. The viscosity of the obtained aqueous emulsion was 550 mPa · s, the solid content was 56.1%,
The average particle diameter was 0.47 μm.

(Example 5) Polymerization was carried out in the same manner as in Example 1 except that the amount of acrylic acid was changed to 7.5 parts. The viscosity of the obtained aqueous emulsion is 450.
mPa · s, solid content is 55.5%, average particle size is
It was 0.47 μm.

Example 6 Polymerization was carried out in the same manner as in Example 2 except that 0.5 part of dodecyl mercaptan was added. The viscosity of the obtained aqueous emulsion is 1
800 mPa · s, solid content 55.6%, average particle size is
It was 0.25 μm.

Example 7 Polymerization was carried out in the same manner as in Example 2 except that 0.2 part of divinylbenzene was added. The viscosity of the obtained aqueous emulsion is 145
0 mPa · s, solid content 55.4%, average particle size is 0.
It was 30 μm.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that 1 part of Eleminol JS-2 (40% active ingredient) was used as the surfactant. The viscosity of the obtained aqueous emulsion was 30 mPa · s, the solid content was 56.3%, and the average particle size was 1.15 μm.

(Comparative Example 2) In Example 1, the surfactant was eleminol JS-2 (active ingredient 40%), 175
Polymerization was performed in the same manner as in Example 1 except that the parts were changed. The viscosity of the obtained aqueous emulsion is 9600 mPa.
s, the solid content was 53.6%, and the average particle diameter was 0.08 μm.

Comparative Example 3 The viscosity of the aqueous emulsion obtained in Example 1 was adjusted to 4700 mPa · s by using a thickener UH-420 (Asahi Denka Kogyo KK).

(Comparative Example 4) In Example 1, the surfactant was 12.5 Eleminol JS-2 (40% active ingredient).
And 5 parts of Neugen EA-80 (Daiichi Kogyo Seiyaku Co., Ltd.) were used, and polymerization was carried out in the same manner as in Example 1. The obtained aqueous emulsion had a viscosity of 400 mPa · s, a solid content of 56.3%, and an average particle diameter of 0.57 μm.

Comparative Example 5 Polymerization was carried out in the same manner as in Example 2 except that 1.5 parts of dodecyl mercaptan was added. The viscosity of the obtained aqueous emulsion is 1
850 mPa · s, solid content 55.2%, average particle size is
It was 0.23 μm.

Comparative Example 6 Polymerization was carried out in the same manner as in Example 2 except that 3 parts of divinylbenzene was added. The viscosity of the obtained aqueous emulsion is 1300 m.
Pa · s, solid content 55.5%, average particle size is 0.33
was μm.

Using the aqueous emulsions obtained in Examples 1 to 7 and Comparative Examples 1 to 6, the following physical property tests were conducted. <Coatability> Using a comma coater (manufactured by Hirano Techseed Co., Ltd.) for the aqueous emulsion type adhesive,
It was coated on a polyethylene terephthalate (PET) film subjected to release treatment so that the coating amount was 18 g / m ² (DRY), and dried in a drying oven at 100 ° C. As the evaluation of the coating property, cissing / staining and smoothness of the pressure-sensitive adhesive coated surface were confirmed, and the drying property of the resin was visually evaluated.

<Adhesive physical properties> (Processed product preparation conditions) Base material 55 g / m2 Fine paper coating Transfer 18 g / m2 (dry) Drying 105 ° C. × 120 seconds curing Room temperature × 1 day (measurement of physical properties of processed product) JIS Z 0237 It was measured according to. Adhesive strength (180 ° peeling): 20 ° C x 65% RH
In the atmosphere, add 1kg of 2kg roller to SUS # 304 plate.
The pieces were reciprocally bonded to each other, and after 20 minutes, the 180 ° peeling force was measured (peeling speed 300 mm / min). (Pass: 1000g
/ In <) Holding power: SUS # 30 in an atmosphere of 20 ° C. × 65% RH
After being adhered to 4 plates and left for 20 minutes, the holding power at 40 ° C. was measured. (Pass: 24 hr <) Ball tack: Ball tack was measured in an atmosphere of 20 ° C. × 65% RH. (J. Dow method) (Pass: 7 <)

<Average particle size> A particle size distribution measuring instrument (Microtrac (UPA150)) manufactured by Nikkiso Co., Ltd. was used (50% frequency value was adopted). The results are shown in Tables 1 and 2.

<Insoluble Tetrahydrofuran Content of Dry Film> An aqueous emulsion having a thickness of 0.1 mm was cast on a release sheet and dried at 20 ° C. and 65% RH for 3 days to form a dry film. 50 g of the obtained dry film 0.5 g
After dipping in 1 l of tetrahydrofuran (THF) at 20 ° C. for 1 day, the mixture was filtered through a 60-mesh filter, the filtered component was dried, weighed, and the THF insoluble content was calculated from the following formula. THF insoluble matter (%) = (weight of dry filtration residue) / (THF
Weight before immersion) x 100

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

EFFECTS OF THE INVENTION According to the present invention, when an aqueous emulsion type pressure-sensitive adhesive does not contain an alkylphenol group-containing compound which is an endocrine disrupting substance, and the aqueous emulsion type pressure-sensitive adhesive is coated on a release sheet, the pressure-sensitive adhesive is Provided are an aqueous emulsion type pressure-sensitive adhesive and a pressure-sensitive adhesive sheet which are free from streaks, cissing, streaks, liquid sagging and the like and have excellent productivity.

Continued front page    (72) Inventor Jiro Uchida             400-5 Toho, Taishi-cho, Ibo-gun, Hyogo Prefecture (72) Inventor Haruki Nishiike             199-85, Nakamura, Tatsuno-cho, Tatsuno-shi, Hyogo F term (reference) 4J004 AA10 AB01 CB03 CC02                 4J011 KA21 KB04 KB08                 4J040 DF041 DF051 DG001 FA00                       HB14 HD13 JA03 JA09 JB09                       KA38 NA05 NA21 NA22

Claims (3)

[Claims] 1. An unsaturated monomer (A) composed of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 14 carbon atoms, a carboxyl group-containing unsaturated monomer (B), and the following formula (1) ) To (26), which is an aqueous emulsion pressure-sensitive adhesive comprising an aqueous emulsion containing at least one surfactant (C), wherein (a) the average particle size of the particles constituting the aqueous emulsion is 0. 1 to 1 μm, (b) the solid content is 50% by weight or more, and (c) the viscosity of the B-type viscometer at 23 ° C. and 60 rpm is 50 mPa · s.
The water-based emulsion pressure-sensitive adhesive is characterized in that it is less than 2000 mPa · s and (d) the dry film formed from the water-based emulsion has a tetrahydrofuran insoluble content of 20 to 80% by weight. [Chemical 1] [Chemical 2] [Chemical 3] [Chemical 4] (In the above formula, R is an alkyl group, M is an ammonium salt or a metal salt, AO is ethylene oxide (EO), propylene oxide (PO) containing alkylene oxide,
ph is a distyrenated phenyl group, n is an integer of 0 to 50, and m is an integer of 0 to 50) 2. The unsaturated monomer (A) is contained in an amount of 85 to 99.8% by weight and the carboxyl group-containing unsaturated monomer (B) is contained in the entire components (A), (B) and (C). The aqueous emulsion type pressure-sensitive adhesive according to claim 1, wherein the surfactant (C) is contained in a proportion of 0.1 to 5% by weight and the surfactant (C) in a proportion of 0.1 to 10% by weight. 3. A pressure-sensitive adhesive sheet obtained by applying the water-based emulsion pressure-sensitive adhesive according to claim 1 or 2 onto a release sheet.