JPH0641505A - Aqueous pressure-sensitive adhesive composition - Google Patents

Abstract

PURPOSE:To obtain an aqueous pressure-sensitive adhesive composition containing a specific COOH-containing (co)polymer, a specific surfactant and a polyvalent metal compound, excellent in solubility or dispersibility to an aqueous solution of alkali and capable of regenerating and then using paper, etc., using as a support. CONSTITUTION:The composition having pH2-5 is obtained by blending 100 pts.wt. total amount of (A) 10-60 pts.wt. COOH-containing (co)polymer obtained by (co)polymerizing A1: 70-100wt.% COOH-containing monomer (preferably acrylic acid) with A2: 0-30wt.% monomer of formula I [R<1> is H or methyl; X is COOR<2>, CONHR<3>, etc., (R<2> is 1-18C alkyl, 6-8C cycloalkyl, etc.; R<3> is H, 1-4C alkyl, etc.)], [e.g. preferably (meth)acrylic acid ester], preferably in an aqueous medium and (B) 90-40 pts.wt. surfactant of formula II [R is 8-12C alkyl, 10-18C alkenyl, etc.; Y is H, 8-18C alkyl, etc.; (m) is natural number of 3-80] with (C) 0.01-1 pts.wt. polyvalent metallic compound (e.g. zinc acetate).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is to form a pressure-sensitive adhesive layer which has excellent tack, adhesive strength, cohesive strength and water resistance when used and is easily dissolved or dispersed in an alkaline aqueous solution. Regarding the water-based pressure-sensitive adhesive composition that can be described in detail, specifically, a specific carboxyl group-containing (co) polymer, a specific surfactant, and an aqueous pressure-sensitive adhesive containing a polyvalent metal compound in specific amounts, respectively. A composition,
It relates to an aqueous pressure-sensitive adhesive composition having a pH within a specific range.

[0002]

2. Description of the Related Art Conventionally, adhesive tapes and labels have been
Because of its simple usage, it is widely used for medical purposes, packaging purposes, price labels, signs, office work, home use and the like. Such adhesive tapes and labels are
The pressure-sensitive adhesive is applied on a support such as paper, woven cloth, non-woven cloth, and synthetic resin film, and generally, it is required to have excellent tack, adhesive strength, cohesive strength and the like.

As such a pressure-sensitive adhesive, generally,
Synthetic rubber-based, natural rubber-based, acrylic resin-based, and the like dissolved in an organic solvent such as toluene and ethyl acetate; dispersed in an aqueous solvent;

However, in recent years, particularly for adhesive tapes and adhesive labels using paper as a support, attempts have been made to redisperse the support paper in an aqueous solvent and regenerate it as pulp from the viewpoint of resource saving. In this case, since the pressure-sensitive adhesive has low solubility or dispersibility in an alkaline aqueous solvent (hereinafter, may be abbreviated as alkali-soluble), if the pressure-sensitive adhesive remains on the support, it is regenerated. It also causes various troubles such as sticking to recycled paper.

In order to solve the above-mentioned problems, it is possible to use a water-soluble pressure-sensitive adhesive, and such a water-soluble pressure-sensitive adhesive is described in, for example, Japanese Patent Publication No. 49-23813. That is, a nonionic surfactant (A) having an ethylene oxide group and an ethylenic monomer having a specific structure of 40 to 90% by weight and a carboxyl group having an ethylenic monomer of 60 to 1% by weight A "low-temperature pressure-sensitive adhesive" composed of a copolymer (B) obtained by copolymerizing and is known.

However, the copolymerization amount of the ethylenic monomer having a carboxyl group in the copolymer (B) in the above-mentioned "pressure sensitive adhesive for low temperature" is in the range of 60 to 1% by weight. On the other hand, the carboxyl group-containing (co) polymer (A) used in the present invention has a carboxyl group in the ethylenic monomer (co) polymerization amount is more than 70-100% by weight range . Further, the water-based pressure-sensitive adhesive composition of the present invention contains a polyvalent metal compound as an essential component, whereas the above proposal does not describe it.

Further, according to additional tests by the present inventors, for example, the "low-temperature pressure-sensitive adhesive" described in the above-mentioned "Example 2" is excellent in cohesive force, but the water of the present invention is used. It was found that the solubility in alkali was completely insufficient and the water resistance was inferior as compared with the pressure-sensitive adhesive composition.

Further, JP-A-60-99180 discloses "Aqueous pressure-sensitive adhesive composition characterized by containing polyacrylic acid, polyacrylic acid salt, cellulose derivative, polyhydric alcohol and polyvalent metal compound. The thing is described.

However, the above-mentioned second proposed "water-based pressure-sensitive adhesive composition" does not contain the surfactant (B) which is an essential component of the water-based pressure-sensitive adhesive composition of the present invention, and has a pH value thereof.
The range is also much higher than that of the composition of the present invention. According to a supplementary test by the present inventors, for example, the “aqueous pressure-sensitive adhesive composition” described in the “Example 1” of the proposal is
Although it was excellent in alkali solubility, it was revealed that the water resistance was extremely poor.

[0010]

DISCLOSURE OF THE INVENTION The present inventors have found that the pressure-sensitive adhesive having excellent tack, adhesive strength, cohesive strength and water resistance, which is particularly suitable for use in an adhesive tape or an adhesive label having paper as a support. A pressure-sensitive adhesive composition which is a composition which is easily dissolved or dispersed in an alkaline aqueous solvent when the support paper is recycled, etc.
For example, containing carboxyl groups such as polyacrylic acid (co)
It contains a polymer, a surfactant such as polyoxyethylene nonylphenol ether (HLB = about 9 to 18), and a polyvalent metal compound such as aluminum chloride in a specific amount, and its pH is about 2 to 5. The present inventors have found that the water-based pressure-sensitive adhesive composition is an excellent one capable of solving all the above problems, and further researched the present invention to complete the present invention.

[0011]

The present invention provides the following (A) and (B),

(A) The following (a-1) and (a-2), (a-1) 70 to 100% by weight of a monomer having a carboxyl group, and (a-2)
0 to 30% by weight of a monomer represented by the following general formula (1),

[0013]

[Chemical 3]

(However, R ¹ is H or CH ₃ , and X is COO.
^{R 2, CONHR 3, OCOR 4} , CN or carbons 6-1
0 aryl group; R ² is a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 6 to 8 carbon atoms, or a carbon number
Alkenyl group having 10 to 18, an aryl group having 6 to 10 carbon atoms, an aralkyl group or _{^{(R 5 O) n R 6}} , R 5 is a linear or branched alkylene group having 2 to 3 carbon atoms 6 to 10 carbon atoms , R ⁶ is H, a linear or branched alkyl group having 1 to 18 carbon atoms, or an aryl group having 6 to 10 carbon atoms, and n is a natural number of 1 to 30;
R ³ is H, a straight-chain or branched alkyl group having 1 to 4 carbon atoms or CH ₂ OR ⁷ , R ⁷ is H or a straight-chain or branched alkyl group having 1 to 18 carbon atoms; R ⁴ is H or the number of carbon atoms 1-18
Is a linear or branched alkyl group; )

[However, the total of (a-1) and (a-2) is 100% by weight]

(B) A surfactant represented by the following general formula (2)
90-40 parts by weight,

[0017]

[Chemical 4]

(Wherein R is an alkyl group having 8 to 18 carbon atoms,
Alkenyl group having 10 to 18 carbon atoms, or alkylphenyl group or dialkylphenyl group having 10 to 30 carbon atoms; Y
Is H, an alkyl group having 8 to 18 carbon atoms, an alkenyl group having 10 to 18 carbon atoms, an alkylphenyl group or a dialkylphenyl group having 10 to 30 carbon atoms, or SO ₃ Z; Z is sodium, potassium or ammonium; m Is a natural number of 3 to 80; )

For a total of 100 parts by weight of

(C) 0.01 to 1.0 part by weight of a polyvalent metal compound,

It is an object of the present invention to provide an aqueous pressure-sensitive adhesive composition containing, which has a pH in the range of 2 to 5. .

The present invention will be described in detail below. Carboxyl group-containing (co) polymer that can be used in the present invention (A)
Is (co) polymerized with the monomer (a-1) having a carboxyl group as a main component. Such monomer (a-1)
Examples thereof include acrylic acid, methacrylic acid, crotonic acid, citraconic acid, itaconic acid, maleic acid, fumaric acid, and the like. These monomers are used alone or in combination of two or more kinds. be able to.

Of these, acrylic acid, methacrylic acid and / or itaconic acid are preferably used from the viewpoints of ease of polymerization and good solubility of the resulting pressure-sensitive adhesive composition in an alkaline aqueous solution. Use is particularly preferred.

The amount of the monomer (a-1) used is 70 to 10 relative to the total 100% by weight of the monomer (a-1) and the monomer (a-2) described later.
It is 0% by weight. If the amount used is too small below the lower limit, the alkali solubility tends to decrease, which is not preferable.

The carboxyl group-containing (co) polymer (A) that can be used in the present invention is, together with the above-mentioned monomer (a-1) having a carboxyl group, if necessary, the following general formula (1) It is obtained by copolymerizing the monomer (a-2) represented by

[0026]

[Chemical 5]

In the above general formula (1), R ¹ is H or CH ₃ , X is COOR ² , CONHR ³ , OCOR ⁴ , C.
N is an aryl group having 6 to 10 carbon atoms, R ² is a linear or branched alkyl group having 1 to 18 carbon atoms, and 6 to 8 carbon atoms.
Cycloalkyl group, an alkenyl group having 10 to 18 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 6 to 10 carbon atoms, or (R ⁵ O) _n R ⁶ and R ^{5 each} have 2 to 3 carbon atoms. A linear or branched alkylene group, R ⁶ is H, a linear or branched alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 10 carbon atoms,
n is a natural number of 1 to 30, R ³ is H, a linear or branched alkyl group having 1 to 4 carbon atoms or CH ₂ OR ⁷ , R ⁷ is H or a linear or branched alkyl group having 1 to 18 carbon atoms. , R ⁴ is H or a linear or branched alkyl group having 1 to 18 carbon atoms.

As the monomer (a-2), X in the general formula (1) is COOR ² , R ¹ is H and R ² is a straight chain or branched chain having 1 to 18 carbon atoms. An acrylic acid ester monomer having a branched alkyl group or an alkenyl group having 10 to 18 carbon atoms can be preferably used.

Specific examples of such acrylic acid ester monomers include, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, i-butyl acrylate, t-butyl acrylate, tridecyl acrylate, Stearyl acrylate, oleyl acrylate, cyclohexyl acrylate, benzyl acrylate and the like can be mentioned.

Further, as the monomer (a-2), the above-mentioned general formula (1)
X is COOR ² , R ¹ is CH ₃ and R ² is a linear or branched alkyl group having 1 to 20 carbon atoms or an alkenyl group having 10 to 18 carbon atoms, and a methacrylic acid ester monomer is preferable. Can be used for

Specific examples of such methacrylic acid ester monomers include, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, n-octyl methacrylate. , 2-ethylhexyl methacrylate, i-decyl methacrylate, lauryl methacrylate, tridecyl methacrylate, cetyl methacrylate, stearyl methacrylate, oleyl methacrylate and the like.

Further, as the monomer (a-2),
X in (1) is COOR ² and R ¹ is H or CH ₃
And (R ⁵ O) _n R ⁶ and R ⁵ are linear or branched alkylene groups having 2 to 3 carbon atoms, R ⁶ is H, linear or branched alkyl group having 1 to 18 carbon atoms, or 6 carbon atoms. ~ 10 aryl groups, n
Is preferably a (meth) acrylic acid ester monomer having a natural number of 1 to 30.

Specific examples of such (meth) acrylic acid ester monomers include, for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate,

Diethylene glycol monoacrylate,
Diethylene glycol monomethacrylate, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monoacrylate, polypropylene glycol monomethacrylate, 2-methoxyethyl acrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate,

Diethylene glycol methyl ether monoacrylate, diethylene glycol methyl ether monomethacrylate, diethylene glycol phenol ether monoacrylate, diethylene glycol phenol ether monomethacrylate, polyethylene glycol methyl ether monoacrylate, polyethylene glycol methyl ether monomethacrylate, polyethylene glycol phenol ether monoacrylate,
Examples thereof include polyethylene glycol phenol ether monomethacrylate.

Examples of the above-mentioned (meth) acrylic acid ester monomers include NK ester M-20G, NK ester M
-40G, NK ester M-90G, NK ester M-230G, NK ester AMP-10G, NK ester AMP-20G, NK ester AMP-60
G, NK ester AM-30G, NK ester AM-90G [above, Shin Nakamura Chemical Co., Ltd.]; Bremmer PP-500, Bremmer PP-800, Bremmer PP-1000, Bremmer PE-90,
Bremmer PE-200, Bremmer PE-350, Bremmer P
Commercially available products such as ME-100, Bremmer PME-200, and Bremmer PME-400 [above, manufactured by NOF CORPORATION] can be used.

As the monomer (a-2), the above-mentioned general formula
X in (1) is CONHR ³ , and R ¹ is H or C
In H ₃ , R ³ is H, a linear or branched alkyl group having 1 to 4 carbon atoms or CH ₂ OR ⁷ , R ⁷ is H or 1 to 18 carbon atoms.
The (meth) acrylamide-based monomer which is a linear or branched alkyl group can be used. ,

Specific examples of such (meth) acrylamide type monomers include, for example, acrylamide, methacrylamide, Nt-octylacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, Nn-.
Mention may be made of (meth) acrylic acid amides such as butoxymethyl acrylamide and derivatives thereof.

As the monomer (a-2), X in the general formula (1) is OCOR ⁴ , R ¹ is H and R ⁴ is H.
Alternatively, a fatty acid vinyl ester-based monomer having a linear or branched alkyl group having 1 to 18 carbon atoms can be used. Specific examples of such a fatty acid vinyl ester-based monomer include:
Examples thereof include vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate (trade name) and the like.

The monomer (a-2) is a monomer in which X in the general formula (1) is CN or an aryl group having 6 to 10 carbon atoms, and R ¹ is H or CH _3. For example, vinyl cyanide-based monomers such as acrylonitrile and methacrylonitrile; aromatic vinyl-based monomers such as styrene, α-methylstyrene, vinyltoluene, and ethylvinylbenzene can be used. Can be mentioned.

The amount of the monomer (a-2) used is 0 to 3 with respect to 100% by weight of the total amount of the monomers (a-1) and (a-2).
It is 0% by weight. If the amount of the monomer (a-2) used exceeds the upper limit and is too large, the alkali solubility tends to decrease, which is not preferable.

The carboxyl group-containing (co) polymer (A) that can be used in the present invention includes at least one of the above-mentioned monomers (a-1) and, if necessary, the monomer (a-2). (Co) polymerization with at least one of the above. The (co) polymerization method is not particularly limited, but it is preferable to perform (co) polymerization using a water-soluble or water-dispersible polymerization initiator in an aqueous solvent or a hydrophilic organic solvent. .

The above-mentioned aqueous solvent means, for example, an aqueous solution of water and a hydrophilic organic solvent, and as the hydrophilic organic solvent,
For example, alcohols such as methyl alcohol, ethyl alcohol and i-propyl alcohol; for example, acetone,
Ketones such as methyl ethyl ketone; and the like. Of these solvents, it is particularly preferable to use water from the viewpoint of safety and low cost.

Examples of the above-mentioned polymerization initiator include persulfates such as ammonium persulfate, potassium persulfate and sodium persulfate; organic compounds such as t-butyl hydroperoxide, cumene hydroperoxide and p-menthane hydroperoxide. Peroxides; hydrogen peroxide; etc. can be used alone or in combination of two or more. The amount of the polymerization initiator used can be appropriately selected, but is, for example, about 0.05 to 1 part by weight, more preferably 100 parts by weight of the monomers (a-1) and (a-2) used. The amount used is, for example, about 0.1 to 0.7 part by weight, particularly preferably about 0.1 to 0.5 part by weight.

In the (co) polymerization, a reducing agent can be used in combination if desired. Examples of the reducing agent include reducing organic compounds such as ascorbic acid, tartaric acid, citric acid and glucose; for example, sodium thiosulfate, sodium sulfite, sodium bisulfite, sodium metabisulfite, sodium formaldehyde sulfoxylate, zinc formaldehyde. Examples thereof include reducing inorganic compounds such as sulfoxylate. The amount of the reducing agent used can be appropriately selected. For example, the amount of the reducing agent used is about 0.05 to 1 part by weight based on 100 parts by weight of the monomers (a-1) and (a-2). It can be illustrated.

The polymerization temperature in the (co) polymerization is
Generally, the temperature range is about 30 to 100 ° C, preferably about 40 to 90 ° C.

The carboxyl group-containing (co) polymer solution used in the present invention thus obtained is not particularly limited, but generally, the solid content is about 10 to 60% by weight, and the pH is 1 to 1.
5. Viscosity less than 200,000cps (B type rotational viscometer, 25 ℃, 20rp
m), and the solid content is about 30% due to the ease of production and good productivity.
15-50% by weight, pH 1.5-4.5, viscosity about 1,000-100,000cp
It is preferably s. The weight average molecular weight (Mw) of the (co) polymer is generally 5,000 to 1,000,000, preferably 1 to
It should be around 500,000.

The composition of the present invention may also be used as a carboxyl group-containing (co) polymer, in addition to the above, for example, Jurimer AC-
10S, Julimer AC-10L, Julimer AC-20L, Julimer AC-10H, Julimer AC-20H (above, Nihon Junyaku Co., Ltd.
Products commercially available under the trade name such as "Production" can be used as well.

The water-based pressure-sensitive adhesive composition of the present invention, together with the above-mentioned carboxyl group-containing (co) polymer (A), has the following general formula:
It contains the surfactant (B) represented by (2).

[0050]

[Chemical 6]

In the above general formula (2), R has 8 to 1 carbon atoms.
8 alkyl group, alkenyl group having 10 to 18 carbon atoms, or alkylphenyl group or dialkylphenyl group having 10 to 30 carbon atoms, Y is H, alkyl group having 8 to 18 carbon atoms,
Alkenyl group having 10 to 18 carbon atoms, alkylphenyl group or dialkylphenyl group having 10 to 30 carbon atoms, or S
O ₃ Z, Z is sodium, potassium or ammonium, and m is a natural number of 3 to 80.

Surfactants that can be used in the present invention
As (B), R in the general formula (2) has 8 to 18 carbon atoms.
An alkyl group, an alkenyl group having 10 to 18 carbon atoms, or
It is an alkylphenyl group having 10 to 30 carbon atoms or a dialkylphenyl group, and Y is H, an alkyl group having 8 to 18 carbon atoms, an alkenyl group having 10 to 18 carbon atoms, or 10 to 10 carbon atoms.
Mention may be made of nonionic surfactants which are 30 alkylphenyl or dialkylphenyl groups.

As such a nonionic surfactant,
For example, polyoxyalkylene alkyl or alkenyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene di (stearyl) ether; for example, polyoxyethylene octylphenol ether, polyoxyethylene Nonylphenol ether, polyoxyethylene (dinonyl)
Examples thereof include polyoxyalkylene alkylphenol ethers such as phenol ether and polyoxyethylene di (nonylphenol) ether;

Among these nonionic surfactants, from the viewpoint of good solubility in water, compatibility with the carboxyl group-containing (co) polymer (A), etc., the value of m is 3 to 80, particularly Is about 5 to 50, HLB is 7 to 19, especially 9 to 1
It is preferable to use a material of about 8.5.

Surfactants that can be used in the present invention
As (B), R in the general formula (2) is an alkyl group having 8 to 18 carbon atoms, an alkenyl group having 10 to 18 carbon atoms, or an alkylphenyl group or dialkylphenyl group having 10 to 30 carbon atoms. And Y is SO ₃ Z, where Z is sodium, potassium or ammonium.

Examples of such anionic surfactants include polyoxyalkylene alkyl or alkenyl ether sulfuric acid ester salts such as polyoxyethylene lauryl ether sulfuric acid sodium salt and polyoxyethylene oleyl ether sulfuric acid ammonium salt; , Polyoxyethylene nonylphenol ether sulfate ester sodium salt, polyoxyethylene octylphenol ether sulfate ester ammonium salt, polyoxyethylene (dinonylphenol) ether sulfate ester ammonium salt, and other polyoxyalkylene alkylaryl ether sulfate ester salts; it can.

Among these anionic surfactants, those which can be preferably used are those having a value of m of 3 to 3 from the viewpoint of good compatibility with the carboxyl group-containing (co) polymer (A). 70, especially about 4 to 30.

Carboxyl group-containing composition of the present invention
The use ratio of the (co) polymer (A) and the surfactant (B) is 10 in total of the carboxyl group-containing (co) polymer (A) and the surfactant (B).
The amount of the (co) polymer (A) is 10 to 60 parts by weight and the amount of the surfactant (B) is 90 to 40 parts by weight based on 0 parts by weight. The (co) polymer (A) is
If the amount is less than 10 parts by weight, the adhesive force and the cohesive force will be insufficient, and if it is more than 60 parts by weight, the tack will be too small.

The water-based pressure-sensitive adhesive composition of the present invention contains a polyvalent metal compound (C) together with the carboxyl group-containing (co) polymer (A) and the surfactant (B). It will be.

As the polyvalent metal compound (C), a water-soluble polyvalent metal salt can be preferably used, and examples of such a metal salt include zinc acetate, zinc formate, zinc sulfate and zinc chloride. Zinc salt; for example, aluminum salt such as aluminum acetate, aluminum nitrate, aluminum sulfate; calcium salt such as calcium acetate, calcium formate, calcium chloride, calcium nitrate, calcium nitrite;

For example, barium salts such as barium acetate, barium chloride and barium nitrite; magnesium salts such as magnesium acetate, magnesium formate, magnesium chloride, magnesium sulfate, magnesium nitrate and magnesium nitrite; for example lead acetate and formic acid. Lead salt such as lead;

For example, nickel salts such as nickel acetate, nickel chloride, nickel nitrate, nickel sulfate; manganese salts such as manganese acetate, manganese chloride, manganese sulfate, manganese nitrate; copper chloride, copper nitrate, copper sulfate, etc. Copper salt; and the like.

The amount of the polyvalent metal compound used in the composition of the present invention is 0.01 to 1.0 parts by weight based on 100 parts by weight of the total of the carboxyl group-containing (co) polymer (A) and the surfactant (B). Parts, preferably 0.05 to 0.5 parts by weight. If the amount used is less than the lower limit and too small, both the adhesive force and cohesive force will be insufficient, and if the amount is more than the upper limit, too much tack and adhesive force will result. Absent.

The water-based pressure-sensitive adhesive composition of the present invention is preferably added to an aqueous solution of a carboxyl group-containing (co) polymer (A) obtained by solution polymerization in an aqueous solution, for example, polyoxyalkylene. A surfactant (B) such as alkylphenol ether is quantitatively mixed, and water and / or the hydrophilic organic solvent described above is added if necessary, or a part of the organic solvent is removed by a known method such as distillation. , A carboxyl group-containing (co) polymer (A), a surfactant (B), a mixture of the various additives optionally added, and then, for example, a polyvalent metal compound such as aluminum chloride It can be produced by adding the aqueous solution of (C), and further adding appropriate water and / or the hydrophilic organic solvent as needed, and uniformly mixing.

The composition of the present invention thus obtained must have a pH of 2 to 5, preferably 2 to 4. p
If H exceeds the upper limit and is too high, the resulting pressure-sensitive adhesive layer tends to have insufficient water resistance, which is not preferable. On the other hand, if it is too low, such as below the lower limit, problems such as corrosion may occur during coating and storage of the composition, which is not preferable.

In addition, the composition of the present invention generally has a solid content of about 10 to 90% by weight and a viscosity of 50,000 cps or less (B-type rotational viscometer, 25 ° C., 20 rpm). It is preferable that the solid content is about 15 to 60% by weight (particularly about 20 to 50% by weight), and the viscosity is about 1,000 to 20,000 cps.

The water-based pressure-sensitive adhesive composition of the present invention is used for forming a pressure-sensitive adhesive layer by a known method, as in the case of an ordinary pressure-sensitive adhesive. That is, in particular, a direct method in which it is directly applied to a support such as paper and dried, and a pressure-sensitive adhesive layer is applied and dried on a release material such as paper or plastic film release-treated with a silicone resin or the like. After the formation, a transfer method is used in which the support is overlaid on the pressure-sensitive adhesive layer and pressed to transfer the pressure-sensitive adhesive layer onto the support.

[0068]

EXAMPLES The present invention will be described in more detail with reference to Examples, Comparative Examples and Reference Examples. The method for preparing the pressure-sensitive adhesive sheet for the physical property test and the methods for measuring tack, adhesive strength, cohesive strength and alkali solubility of the pressure-sensitive adhesive layer are as follows.

(1) Method for preparing pressure-sensitive adhesive sheet for physical property test Aqueous pressure-sensitive adhesive composition solution was dried using a doctor blade so that the pressure-sensitive adhesive layer after drying would be ²⁰ to 25 g / m ^2. To 90 ° C. for 90 seconds in a hot-air circulation dryer, and then transferred to a high-quality paper (about 81.4 g / m ² ) to prepare a pressure-sensitive adhesive sheet for physical property testing.

(2) Tack measurement According to J. DOW method, a test piece cut out from the pressure-sensitive adhesive sheet for physical property test (about 50
mm × 100 mm), a steel ball with a diameter x / 32 inch is rolled from a position 100 mm above the slope of the test piece, and the diameter x of the ball with the maximum diameter that stops on the test piece is used as the tack value.

(3) Measurement of adhesive strength SUS 3 polished with # 280 water resistant abrasive paper specified in JIS R-6253
A test piece (approx. 25 mm x 150 m) cut out from the pressure-sensitive adhesive sheet for physical property test created in (1) above on the 04 stainless steel plate.
m) is crimped according to the method of JIS Z-0237, and after 1 hour, 23
The peel strength (g / 25 mm) is measured under conditions of ℃, 65% RH and peeling speed of 300 mm / min.

(4) Measurement of cohesive force A test piece (about 100 mm × 25 mm) cut out from the pressure-sensitive adhesive sheet for physical property test prepared in the above (1), on the same stainless steel plate as used in the above (3) Was stuck so that the sticking area would be 25 × 25 mm 2, and a 2 kg roller was reciprocated once to perform pressure bonding. A static load of 1 kg is applied to the test piece in an atmosphere of 40 ° C. and 30% RH, and the time (minute) until the load drops is measured to obtain the cohesive force value.

(5) Water resistance test Cut out from the pressure-sensitive adhesive sheet for physical property test prepared in (1) above to a polyethylene plate (surface tension γ ₀ = 43 dyn / cm according to the method specified in JIS K-6768). Test piece (about 100 mm x 2
5 mm) so that the attachment area is 25 × 25 mm ² JIS Z
Crimping according to the method of -0237, 1 in deionized water at 23 ℃
After being immersed for a period of time, the state of peeling from the polyethylene plate is observed and evaluated as follows.

○ ・ ・ ・ ・ ・ ・ No peeling. △ ・ ・ ・ ・ Slightly peeled off. × ・ ・ ・ ・ Peels off completely.

(6) Alkali Solubility Test of Pressure-Sensitive Adhesive Layer A test piece (about 25 mm × 50 mm) cut out from the pressure-sensitive adhesive sheet for physical property test prepared in the above (1) was applied at 5 weight at a liquid temperature of 25 ° C. %
It is put in 100 ml of an aqueous solution of sodium hydroxide and stirred, and the state of the pressure-sensitive adhesive layer when the high-quality paper is dispersed is observed and evaluated as follows.

◯ ... The pressure-sensitive adhesive layer dissolves. × ・ ・ ・ ・ ・ ・ The pressure-sensitive adhesive layer did not dissolve.

Reference Example 1 Deionized water 25 was placed in a separable flask equipped with a reflux condenser, a thermometer, a stirrer, a sequential dropping device and a nitrogen introducing tube.
0 part by weight was charged and the internal temperature was raised to 80 ° C. The contents of the flask were stirred under a nitrogen stream, 100 parts by weight of acrylic acid (AA) while maintaining the internal temperature at 80 ° C, and a 5% by weight aqueous solution of t-butyl hydroperoxide (BHPO) as a polymerization initiator.
10 parts by weight and 10 parts by weight of a 5% by weight aqueous solution of sodium formaldehyde sulfoxylate [trade name "Rongalit C", manufactured by Wako Pure Chemical Industries, Ltd.] as a reducing agent were sequentially added over 2 hours, respectively, and further at the same temperature. The reaction was continued for 2 hours.

Then, deionized water 15 was added to the obtained polymerization reaction liquid.
The mixture was diluted with 0 part by weight to obtain an acrylic acid polymer aqueous solution having a solid content of about 20% by weight. The viscosity of the resulting aqueous polymer solution,
Table 1 shows the solid content, pH, Mw and glass transition point (Tg) of the polymer.

Reference Examples 2 to 3 In the same manner as in Reference Example 1, except that the amounts of the polymerization initiator BHPO aqueous solution and the reducing agent Rongalit C aqueous solution used were changed, and the dilution water amount of the polymerization reaction solution was adjusted. M
Acrylic acid polymer aqueous solutions having different w were obtained. Table 1 shows the viscosity, solid content and pH of the resulting aqueous polymer solution, and Mw and glass transition point (Tg) of the polymer.

Reference Examples 4 to 5 Instead of using 100 parts by weight of AA in Reference Example 1, AA
75 parts by weight and methyl acrylate (MA) 25 parts by weight, or AA 75 parts by weight and methoxyethyl acrylate (ME
A) An aqueous acrylic acid copolymer solution was obtained in the same manner as in Reference Example 1 except that 25 parts by weight was used. Table 1 shows the viscosity, solid content and pH of the obtained aqueous copolymer solution, and Mw and glass transition point (Tg) of the polymer.

Comparative Reference Example 1 The same reactor as in Reference Example 1 was used. MA 50 in a separate container
Parts by weight, 50 parts by weight of AA, 100 parts by weight of methyl alcohol (MeOH) and 1.0 part by weight of azobis-i-butyronitrile (AIBN) are mixed uniformly to prepare a monomer mixture, of which 25% by weight is reacted as an initial charge. The mixture was placed in an apparatus, heated with stirring, and polymerized under reflux for 40 minutes. Then, the remaining 75% by weight of the mixture was sequentially added over about 2 hours to polymerize under reflux, and further refluxed for about 2 hours. Continued.

Then, 300 parts by weight of MeOH was added to the obtained polymerization reaction solution to dilute it to obtain an acrylic copolymer solution having a solid content of about 20% by weight. Table 1 shows the viscosity, solid content and pH of the obtained copolymer solution, and Mw and glass transition point (Tg) of the polymer.

Comparative Reference Example 2 In the same apparatus as in Reference Example 1, 150 parts by weight of deionized water,
0.2 parts by weight of ammonium persulfate (APS) as a polymerization initiator and sodium metabisulfite (SMBS) 0.2 as a reducing agent
Part by weight was charged and the internal temperature was raised to 70 ° C. On the other hand, 100 parts by weight of deionized water in another container, 1.0 part by weight of polyoxyethylene alkylphenol ether type nonionic surfactant (HLB about 11) as an emulsifier and 1.0 part by weight of sodium salt of dodecylbenzene sulfonate type anionic surfactant. Part, charge and dissolve with stirring,

Then, a monomer mixture consisting of 50 parts by weight of MA, 38 parts by weight of methyl methacrylate (MMA) and 12 parts by weight of AA was added thereto and stirred to obtain a monomer premix.
The contents of the reactor were stirred under a nitrogen stream, and while maintaining the internal temperature at 70 ° C., the monomer premix was sequentially added to initiate polymerization, and polymerization was performed for about 2 hours. After completion of the polymerization, stirring was continued at the same temperature for about 1 hour and then cooled, and the pH was adjusted with aqueous ammonia to obtain an aqueous dispersion of an acrylic copolymer having a solid content of about 30% by weight. Table 1 shows the viscosity, solids content and pH of the obtained aqueous copolymer dispersion, and the Mw and glass transition point (Tg) of the copolymer.

Comparative Reference Example 3 Instead of using 150 parts by weight of deionized water initially charged and 100 parts by weight of deionized water for the monomer premix in Comparative Example 2, 66 parts by weight and 20 parts by weight of deionized water, respectively. Using 0.4 parts by weight of dodecylbenzene sulfonic acid sodium salt type anionic surfactant instead of 1.0 parts by weight, MA 50 parts by weight, MMA 38 parts by weight and AA as a monomer
An aqueous dispersion of an acrylic copolymer having a solid content of 53.9% by weight was obtained in the same manner except that 84 parts by weight of 2-ethylhexyl acrylate (EHA), 15 parts by weight of MA and 1 part by weight of AA were used instead of using 12 parts by weight. It was Table 1 shows the viscosity, solids content and pH of the obtained aqueous copolymer dispersion, and the Mw and glass transition point (Tg) of the copolymer.

[0086]

[Table 1]

Example 1 As the carboxyl group-containing (co) polymer (A), 165 parts by weight of the aqueous acrylic acid polymer solution obtained in Reference Example 1 (solid content: about 3
3 parts by weight), and as a surfactant (B), Emulgen 910 [trade name; polyoxyethylene alkylphenol ether-based nonionic surfactant; m = 8 to 1]
0: HLB about 12; manufactured by Kao Corporation] (E910) 67 parts by weight and 0.2 parts by weight of aluminum chloride (AlCl ₃ ) as a polyvalent metal compound (C) dissolved in 1.8 parts by weight of deionized water, and 167 parts by weight of diluting methanol was mixed with stirring to obtain an aqueous pressure-sensitive adhesive composition. The composition of the composition obtained is shown in Table 1.
Tables 2 and 3 show the measurement results of basic physical properties and various physical properties.

Examples 2 to 3 and Comparative Examples 1 and 2 In Example 1, the polyvalent metal compound AlCl _{3 was} prepared by changing the compounding ratio of the acrylic acid polymer of Reference Example 1 and the surfactant E910.
An aqueous pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that the addition amount of was changed. The compounding composition of the obtained composition is shown in Table 1, and the measurement results of basic physical properties and various physical properties are shown in Tables 2 and 3.

Examples 4 to 6 Instead of using E910 as the surfactant in Example 1, Emulgen 905 [trade name; polyoxyethylene alkylphenol ether nonionic surfactant; m
≈5; HLB approx. 9.2; manufactured by Kao Corporation] (E905), Emulgen 93
0 [trade name; polyoxyethylene alkylphenol ether nonionic surfactant; m≈30; HLB approx. 15.1; manufactured by Kao Corporation] (E930) or Emulgen 950 [trade name; polyoxyethylene alkylphenol ether nonionic surfactant] Activator; m ≈ 50; HLB approx. 18.2; Kao Corporation] (E95
An aqueous pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that (0) was used. The composition of the composition obtained is shown in Table 1.
Tables 2 and 3 show the measurement results of basic physical properties and various physical properties.

Example 7 As the carboxyl group-containing (co) polymer (A), 100 parts by weight of the acrylic acid polymer aqueous solution obtained in Reference Example 1 (solid content: about 2) was used.
On the other hand, as the surfactant (B), Hitenol N-08 [trade name; polyoxyethylene alkylphenol ether sulfate ester type anionic surfactant; m≈6; Daiichi Kogyo Co., Ltd. Pharmaceutical Co., Ltd.) (HN08) 80 parts by weight and AlCl ₃ 0.2 parts by weight as a polyvalent metal compound (C) dissolved in 1.8 parts by weight of deionized water, and 100 parts by weight of diluting methanol were mixed by stirring. A water-based pressure-sensitive adhesive composition was obtained. The compounding composition of the obtained composition is shown in Table 1, and the measurement results of basic physical properties and various physical properties are shown in Tables 2 and 3.

Example 8 In Example 7, instead of using HN08 as the surfactant, Hitenol NE-05 [trade name; polyoxyethylene (dialkylphenol) ether sulfate ester anionic surfactant; m≈ 6; manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.]
An aqueous pressure-sensitive adhesive composition was obtained in the same manner as in Example 7 except that (HNE05) was used. The compounding composition of the obtained composition is shown in Table 1, and the measurement results of basic physical properties and various physical properties are shown in Tables 2 and 3.

Example 9 In Example 7, the aqueous solution of the acrylic acid polymer of Reference Example 1 was used.
Instead of using 100 parts by weight (solid content: about 20 parts by weight) and 80 parts by weight of HN08 as a surfactant, 205 parts by weight of the acrylic acid polymer aqueous solution of Reference Example 1 (solid content: about 41 parts by weight) and a surfactant are used. Trax K-300 [trade name; polyoxyethylene alkylphenol ether sulfate ester type anionic surfactant; m≈30; solid content about 36% by weight; manufactured by NOF Corporation] (TK300) 164 parts by weight (solid content (Approximately 59 parts by weight)
An aqueous pressure-sensitive adhesive composition was obtained in the same manner as in Example 7 except that was used. The composition of the composition obtained is shown in Table 1.
The measurement results of basic physical properties and various physical properties are shown in Tables 2 and 3.

Example 10 and Comparative Examples 3 to 4 In Example 1, except that the addition amount of the polyvalent metal compound AlCl ₃ was changed or was not added, and the usage amount of methanol for dilution was adjusted. An aqueous pressure-sensitive adhesive composition was obtained in the same manner as in Example 1. The compounding composition of the obtained composition is shown in Table 1, and the measurement results of basic physical properties and various physical properties are shown in Tables 2 and 3.

Comparative Example 5 As the carboxyl group-containing (co) polymer (A), 166.5 parts by weight of the acrylic acid polymer aqueous solution (solid content of about 33.3 parts by weight) obtained in Reference Example 1 was used as a 25% by weight sodium hydroxide aqueous solution. 14.8
66.6 parts by weight of glycerin (Glyc), 117 parts by weight of cellulose sodium salt (CMC) and a polyvalent metal compound are used, which are partially neutralized with parts by weight.
As (C), 0.1 parts by weight of alum dissolved in 0.9 parts by weight of deionized water and 380 parts by weight of diluting methanol were stirred and mixed to obtain an aqueous pressure-sensitive adhesive composition. The compounding composition of the obtained composition is shown in Table 1, and the measurement results of basic physical properties and various physical properties are shown in Tables 2 and 3.

Examples 11 to 14 In Example 1, except that the aqueous solution of acrylic acid polymer obtained in Reference Example 1 was used instead of the aqueous solution of acrylic acid (co) polymer obtained in Reference Examples 2 to 5. An aqueous pressure-sensitive adhesive composition was obtained in the same manner as in Example 1. The compounding composition of the obtained composition is shown in Table 1, and the measurement results of basic physical properties and various physical properties are shown in Tables 2 and 3.

Comparative Example 6 Example 1 was repeated except that the acrylic acid copolymer methyl alcohol solution obtained in Comparative Reference Example 1 was used instead of the acrylic acid polymer aqueous solution obtained in Reference Example 1. An aqueous pressure-sensitive adhesive composition was obtained in the same manner as. The compounding composition of the obtained composition is shown in Table 1, and the measurement results of basic physical properties and various physical properties are shown in Tables 2 and 3.

Comparative Example 7 Acrylic acid copolymer aqueous dispersion obtained in Comparative Reference Example 2
To 148 parts by weight (solid content: about 44.4 parts by weight), 59.6 parts by weight of E910 as a surfactant and 130 parts by weight of isopropyl alcohol for dilution were added and mixed by stirring to obtain an aqueous pressure-sensitive adhesive composition. The composition of the composition obtained is shown in Table 1.
The measurement results of basic physical properties and various physical properties are shown in Tables 2 and 3.

Comparative Example 8 Aqueous dispersion of acrylic acid copolymer obtained in Comparative Reference Example 3
186 parts by weight (solid content: about 100 parts by weight) 0.6 parts by weight aqueous solution of dioctyl sulfosuccinate sodium salt (anionic surfactant) as a surfactant 0.6 parts by weight (solids content: about 0.24 parts by weight) Was added, and then a methacrylic acid copolymer emulsion thickener and aqueous ammonia were added to adjust the viscosity to obtain an aqueous dispersion-type pressure-sensitive adhesive composition. The compounding composition of the obtained composition is shown in Table 1, and the measurement results of basic physical properties and various physical properties are shown in Tables 2 and 3.

[0099]

[Table 2]

[0100]

[Table 3]

[0101]

INDUSTRIAL APPLICABILITY The present invention contains a specific carboxyl group
A (co) polymer, a specific surfactant, and a water-based pressure-sensitive adhesive composition containing a polyvalent metal compound in a specific amount, respectively, wherein the pH is in a specific range. The present invention relates to a pressure-sensitive adhesive composition.

The water-based pressure-sensitive adhesive composition of the present invention can be used particularly as a pressure-sensitive adhesive tape or a pressure-sensitive adhesive label having paper as a support, and when it is used, it is almost the same as a pressure-sensitive adhesive which has been widely used conventionally. It has the characteristics of tackiness, adhesive strength and cohesive strength, and is easily dissolved or dispersed in an alkaline aqueous solvent. Therefore, for the purpose of reusing the paper used as a support, when redispersed in an alkaline aqueous solvent to give a recycled pulp,
Even if the pressure-sensitive adhesive remains on the support, it has an outstanding property that it does not cause troubles such as adhesion of the pressure-sensitive adhesive to a recycling device or recycled paper.

Claims (1)

[Claims] 1. The following (A) and (B), (A) the following (a-1) and (a-2), (a-1) 70 to 100% by weight of a monomer having a carboxyl group, and (a-2) The following general formula (1)
The monomer represented by 0 to 30% by weight, (However, R ¹ is H or CH ₃ , X is COOR ² , CON
HR ³ , OCOR ⁴ , CN or an aryl group having 6 to 10 carbon atoms; R ² is a straight chain or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 6 to 8 carbon atoms, and 10 to 18 carbon atoms. Alkenyl group, aryl group having 6 to 10 carbon atoms, 6 to carbon atoms
10 aralkyl groups or (R ⁵ O) _n R ⁶ and R ⁵ have 2 to 2 carbon atoms.
3 straight-chain or branched alkylene group, R ⁶ is H, straight-chain or branched alkyl group having 1 to 18 carbon atoms, or aryl group having 6 to 10 carbon atoms, n is a natural number of 1 to 30; R ³ Is H,
A linear or branched alkyl group having 1 to 4 carbon atoms or CH
₂ OR ⁷ and R ⁷ are H or a linear or branched alkyl group having 1 to 18 carbon atoms; R ⁴ is H or a linear or branched alkyl group having 1 to 18 carbon atoms; ) (However, (a-1) and (a-
The total of 2) is 100% by weight] 10 to 60 parts by weight of a carboxyl group-containing (co) polymer obtained by (co) polymerization, and (B) the surface activity represented by the following general formula (2): 90-40 parts by weight of agent, [Chemical formula 2] (However, R is an alkyl group having 8 to 18 carbon atoms and 10 to 18 carbon atoms.
Alkenyl group, or an alkylphenyl group or dialkylphenyl group having 10 to 30 carbon atoms; Y is H, an alkyl group having 8 to 18 carbon atoms, an alkenyl group having 10 to 18 carbon atoms, or an alkylphenyl group having 10 to 30 carbon atoms. A group or a dialkylphenyl group, or SO ₃ Z; Z is sodium, potassium or ammonium; m is a natural number of 3 to 80; (C) 0.01 to 1.0 part by weight of a polyvalent metal compound with respect to 100 parts by weight in total, and the pH thereof is in the range of 2 to 5. A water-based pressure-sensitive adhesive composition comprising: