JP2005089518A - Method for producing aqueous dispersion of polymer for aqueous adhesive and aqueous adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous adhesive which has excellent suitability for roll coating processes capable of coating the adhesive to give the smooth surface of the adhesive and can form an adhesive layer having good adhesivity, holdability, processability and water resistance. <P>SOLUTION: This method for producing the aqueous dispersion of a polymer for the aqueous adhesive comprises the first process of emulsion-polymerizing 0.5 to 10 wt.% of a carboxyl group-containing monomer-containing radically polymerizable unsaturated monomer (X) in an aqueous medium in the presence of 0.5 to 5.0 pts.wt. of a chain transfer agent and 0.05 to 1.0 pt.wt. of a reactive surfactant to obtain the primary polymer; the second process of adding a basic substance to the primary polymer to obtain the aqueous solution or dispersion of the primary polymer; and the third process of adding a radically polymerizable unsaturated monomer (Y) except aromatic monomers and a reactive surfactant to the aqueous solution or dispersion of the primary polymer and then emulsion-polymerizing the mixture to obtain the secondary polymer, wherein the amount of the reactive surfactant supplied to the third process is 0.5 to 5.0 pts.wt. based on the total monomers. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing an aqueous dispersion of a polymer, an aqueous dispersion thereof, and an aqueous pressure-sensitive adhesive containing the aqueous dispersion. In detail, it is related with the manufacturing method of the aqueous dispersion suitable for the adhesive which can be used for various base materials, such as paper, a film, a metal, and cloth. More specifically, it is a method for producing an aqueous polymer dispersion capable of providing a pressure-sensitive adhesive having excellent roll coatability that can be smoothly applied to the surface of the pressure-sensitive adhesive, wherein the pressure-sensitive adhesive has adhesive strength, holding power, workability, and water resistance. A good pressure-sensitive adhesive layer can be formed.

  Conventionally, emulsion polymerization methods have been widely used as polymerization methods for aqueous dispersions obtained by polymerizing unsaturated monomers capable of radical polymerization. As a general emulsion polymerization method, there is a method in which a surfactant is used in an aqueous medium and radical polymerization is performed in the micelle. The aqueous dispersion produced by this method has a high molecular weight, and excellent physical properties can be obtained when it is used as a resin for an adhesive. In particular, since it has a high molecular weight, it has excellent holding power, but on the other hand, the adhesive strength is reduced. Further, the viscosity of the obtained aqueous dispersion is strong in thixotropic properties, and it is difficult to apply a streak or repel due to poor flow, and it is difficult to apply the adhesive surface smoothly.

  On the other hand, an emulsion polymerization method using a water-soluble resin as a polymer emulsifier is known in contrast to the emulsion polymerization method described above. The water dispersion made by this method has a relatively large amount of water-soluble resin, so the viscosity is close to Newtonian, and the adhesive surface can be applied smoothly, and is suitable for coating by roll coating. There are features. However, since a relatively large amount of water-soluble resin is used, it has a drawback of poor water resistance.

  In order to solve this problem, it is conceivable to reduce the amount of the acid-containing monomer used, but the polymerization stability and the stability over time of the obtained aqueous dispersion are deteriorated. As the polymer emulsifier used in this method, various water-soluble resins are used, and as a production method by radical polymerization using this, a method by solution polymerization, bulk polymerization, emulsion polymerization or the like is known.

  Among these methods, the solution polymerization method requires solvent removal and is not efficient and economical. The bulk polymerization method requires a step of dissolving the obtained solid resin in water, and has a problem in efficiency.

On the other hand, the method by emulsion polymerization is the most efficient method because the next polymerization can be carried out continuously.
For example, Patent Document 1 discloses a method in which a non-reactive surfactant is used, a hydrophilic primary polymer is prepared by emulsion polymerization, and then a hydrophobic secondary polymer is emulsion polymerized. (See JP-A-2-22302).
However, since this method uses a non-reactive surfactant, when used in a pressure-sensitive adhesive, a non-reactive surfactant remains in the pressure-sensitive adhesive, which adversely affects water resistance. Further, the polymer emulsifier of the primary polymer obtained by the method tends to be uneven in the distribution of the hydrophilic monomer and the hydrophobic monomer, and when the secondary polymer is polymerized by the method described above, the dispersion is It became unstable and aggregates were easily generated. Moreover, the obtained aqueous dispersion has a high solid content, and a fine particle size cannot be obtained, which is disadvantageous in terms of coating suitability.
JP-A-2-22302

  Then, this invention makes it a subject to provide the water-based adhesive which is excellent in the roll coat aptitude which can apply the adhesive surface smoothly.

That is, the present invention provides a carboxyl group-containing single amount of 0.5 to 10% by weight in the case where the total amount of unsaturated monomers subjected to the following first and third steps is 100% by weight in an aqueous medium. The radical-polymerizable unsaturated monomer (X) containing the isomer is 0.5 to 5.0 parts by weight of the chain transfer agent and the total unsaturated monomer 100 with respect to 100 parts by weight of the total unsaturated monomer. An aqueous dispersion of the primary polymer (a) is obtained by emulsion polymerization using a surfactant having one or more radically polymerizable unsaturated groups of 0.05 to 1.0 parts by weight with respect to parts by weight. First step;
A basic substance is added to the aqueous dispersion of the primary polymer (a) to neutralize the primary polymer (a) to obtain an aqueous solution or aqueous dispersion of the primary polymer (a ′). Steps; and
A non-aromatic radically polymerizable unsaturated monomer (Y), a surfactant having one or more radically polymerizable unsaturated groups, and an aqueous medium are mixed, and the mixture is mixed with the primary polymer ( a third step of obtaining an aqueous dispersion of the secondary polymer (b) by emulsion polymerization in addition to the aqueous solution or aqueous dispersion of a ′)
And the amount of the surfactant having one or more radically polymerizable unsaturated groups provided in the third step is 100 parts by weight of the total unsaturated monomers provided in the first and third steps. It is related with the manufacturing method of the aqueous dispersion of the polymer for aqueous adhesives which is 0.5-5.0 weight part with respect to this.

  The present invention also relates to the weight of the radically polymerizable unsaturated monomer (X) provided for the first step and the radically polymerizable unsaturated monomer (Y) provided for the third step. It is related with the manufacturing method as described in the said invention characterized by the ratio being (X) :( Y) = 1: 9-2: 8.

The present invention also relates to an aqueous dispersion of a polymer for aqueous pressure-sensitive adhesives produced by the production method described in the above invention,
Furthermore, this invention relates to the aqueous dispersion as described in the said invention, wherein the particle diameter of the aqueous dispersion of the polymer for aqueous adhesives is 5-100 nm.

  According to the present invention, it is an aqueous pressure-sensitive adhesive that can be used for various substrates such as paper, film, metal, and cloth, and is excellent in roll coat suitability, and has good adhesion, holding power, workability, and water resistance. An aqueous pressure-sensitive adhesive that can form a pressure-sensitive adhesive layer can be provided.

  Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to the following descriptions.

In the present invention, emulsion polymerization is carried out twice (first step and third step) in order to produce the desired aqueous dispersion.
The first step is a step of polymerizing the primary polymer (a), and when the total unsaturated monomers used for the polymerization of the first step and the third step are 100% by weight, 0.5 to 5.0 wt% of the radically polymerizable unsaturated monomer (X) containing 0.5 to 10 wt% of the carboxyl group-containing monomer with respect to 100 wt parts of the total unsaturated monomers. Primary polymer (a) by emulsion polymerization in an aqueous medium using a part of chain transfer agent and 0.05 to 1.0 part by weight of a surfactant having one or more radically polymerizable unsaturated groups To obtain an aqueous dispersion.

  In the first step, the radically polymerizable unsaturated monomer (X) comprises a carboxyl group-containing monomer and other radically polymerizable unsaturated monomer.

  As the carboxyl group-containing monomer used in the present invention, one or two kinds of polymerizable unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and crotonic acid and their anhydrides are used. More than species can be selected.

The carboxyl group-containing monomer that is subjected to polymerization in the first step is 0.1% when the total amount of unsaturated monomers that are subjected to polymerization in the first step and the third step is 100% by weight. It is important that it is 5 to 10% by weight, and preferably 1 to 5% by weight. When the total unsaturated monomer is 100% by weight, if the carboxyl group-containing monomer is less than 0.5% by weight, the polymerization stability is poor and a large amount of aggregates are generated, which adversely affects production efficiency. . On the other hand, when it is more than 10% by weight, the water resistance of the coating film is deteriorated when it is used as an adhesive.
Further, the carboxyl group-containing monomer to be polymerized in the first step is 10 to 20% by weight in the radical polymerizable unsaturated monomer (X) used in the first step. Preferably, it is 15 to 20% by weight.

Other unsaturated monomers capable of radical polymerization used in the present invention include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, and isoamyl acrylate. Alkyl acrylates such as n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate, dodecyl acrylate;
Methyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, decyl methacrylate, dodecyl methacrylate, Alkyl methacrylates such as acetoacetoxyethyl methacrylate;
Hydroxy group-containing monomers such as hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate;
N-substituted acrylic and methacrylic monomers such as N-methylol acrylamide, N-butoxymethyl acrylamide, N-methylol methacrylamide, N-butoxymethyl methacrylamide;
One type or two or more types can be selected from epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate; and acrylonitrile.

In the present invention, a chain transfer agent is used for molecular weight adjustment.
Mercaptans such as octyl thioglycolate, methoxybutyl thioglycolate, octyl mercaptopropionate, methoxybutyl mercaptopropionate, stearyl mercaptan, α-methylstyrene dimer, and the like can be used.
It is important to use the chain transfer agent particularly during the emulsion polymerization of the primary polymer (a), and it is preferable not to use it during the emulsion polymerization in the third step. That is, when a primary polymer (a) having a large molecular weight is obtained without using a chain transfer agent, and the primary polymer (a) is used as a polymer emulsifier in the third step described later, sufficient emulsifying power is obtained. Cannot be obtained. On the other hand, if an excessive amount of the chain transfer agent is used in the first step, a low molecular weight primary polymer (a) will be obtained, and such a low molecular weight primary polymer (a) will be described later. When used as a polymer emulsifier in this step, emulsifying power is obtained.
Therefore, the chain transfer agent used in the first step is 0.5 to 5.0 parts by weight when the entire radical polymerizable unsaturated monomer used in the first and third steps is 100 parts by weight. It is important to use 5 to 50 parts by weight, preferably 5 to 10 parts by weight based on 100 parts by weight of the radically polymerizable unsaturated monomer (X) used in the first step. More preferably. Moreover, 1000-70000 are preferable and, as for the weight average molecular weight of the obtained primary polymer (a), it is more preferable that it is 5000-50000.

Next, the surfactant used in the first step will be described.
The neutralized product (a ′) of the primary polymer (a) described later functions as an emulsifier when obtaining the secondary polymer (b). In obtaining an aqueous dispersion of the primary polymer (a), the amount of the carboxyl group-containing monomer constituting the primary polymer (a) is reduced by using a so-called general low molecular weight surfactant. It becomes possible to reduce. As a result, the water resistance of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive containing the aqueous dispersion of the secondary polymer (b) can be improved. Of general low molecular weight surfactants, reactive surfactants having one or more radical polymerizable unsaturated groups, not non-reactive surfactants having no radical polymerizable unsaturated groups By using this, it is possible to obtain a pressure-sensitive adhesive having better water resistance.

  The reactive surfactant having one or more radically polymerizable unsaturated groups used in the present invention is, for example, sulfosuccinic acid ester-based (commercially available products include, for example, LATEMUL S-120, S-180 manufactured by Kao Corporation. , S-180A, Sanyo Chemical Co., Ltd., Eleminol JS-2, etc.) and alkyl ethers (commercially available products include, for example, Aqualon KH-05, KH-10, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., ADEKA manufactured by Asahi Denka Kogyo Co., Ltd. Rear soap SR-10, SR-20, ER-10, 20, 30, 40, etc.).

In the emulsion polymerization in the first step, one or more of these are mixed and used.
When the amount of the surfactant having one or more radically polymerizable unsaturated groups is small and emulsification is insufficient, a non-reactive surfactant can be used in combination as necessary.
However, as described above, it is preferable to avoid as much as possible because it is thought to adversely affect the water resistance of the coating film.
As the non-reactive surfactant, anionic and nonionic surfactants used in usual emulsion polymerization can be used.

  The surfactant having one or more radically polymerizable unsaturated groups used in the first step is 0.1% by weight based on 100 parts by weight of all unsaturated monomers capable of radical polymerization used in the first and third steps. It is important to use 05 to 1.0 parts by weight, and more preferably 0.05 to 0.2 parts by weight. If it is less than 0.05 parts by weight, the stability of the aqueous dispersion during polymerization is poor and aggregation tends to occur. On the other hand, when the amount is more than 1.0 part by weight, the stability during polymerization is improved, but the hydrophilic part increases in the primary polymer (a), and the resulting aqueous dispersion has a high viscosity and a high solid content. An aqueous dispersion cannot be obtained. Further, the surfactant having one or more radical polymerizable unsaturated groups used in the first step is based on 100 parts by weight of the radical polymerizable unsaturated monomer (X) used in the first step. In such a case, it is preferable to use 0.5 to 10 parts by weight, and more preferably 0.5 to 2 parts by weight.

  As the second step of the present invention, a basic substance is added to the aqueous dispersion of the primary polymer (a), and the carboxyl group in the primary polymer (a) derived from the carboxyl group-containing monomer is added. By neutralization, an aqueous solution or dispersion of the primary polymer (a ′) is obtained. By this operation, the primary polymer (a) can sufficiently exhibit the function as a polymer emulsifier.

Examples of basic substances for neutralization include ammonia; alkylamines such as trimethylamine, triethylamine, and butylamine; alcohol amines such as 2-dimethylaminoethanol, diethanolamine, triethanolamine, and aminomethylpropanol; bases such as morpholine. Can be neutralized.
In the present invention, neutralization means reacting a carboxyl group derived from a carboxyl group-containing monomer with a base of a basic substance, and the pH after neutralization does not necessarily have to be around 7. . Therefore, the degree of neutralization is not particularly limited, and can be carried out as long as the primary polymer (a ′) functions as a polymer emulsifier.

  In the third step of the present invention, the radically polymerizable unsaturated monomer (Y) other than the aromatic monomer, a surfactant having one or more radically polymerizable unsaturated groups, and an aqueous medium After mixing and emulsifying, the mixture is added to the aqueous solution or dispersion of the primary polymer (a ′) and emulsion polymerization is performed to obtain an aqueous dispersion of the secondary polymer (b).

The unsaturated monomer (Y) capable of radical polymerization other than the aromatic monomer used in the third step includes methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, acrylic acid Alkyl acrylates such as isobutyl, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate, dodecyl acrylate;
Methyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, decyl methacrylate, dodecyl methacrylate, Alkyl methacrylates such as acetoacetoxyethyl methacrylate;
Hydroxy group-containing monomers such as hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate;
N-substituted acrylic and methacrylic monomers such as N-methylol acrylamide, N-butoxymethyl acrylamide, N-methylol methacrylamide, N-butoxymethyl methacrylamide;
Examples include epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate; and acrylonitrile. One or more of these can be selected.

  As described above, in the third step, the present invention is an interface in which the radically polymerizable unsaturated monomer (Y) other than the aromatic monomer has at least one radically polymerizable unsaturated group. After mixing with an activator and an aqueous medium and emulsifying, the mixture is subjected to emulsion polymerization in the presence of an aqueous solution or dispersion of the primary polymer (a ′) to obtain an aqueous dispersion of the secondary polymer (b). Get. The polymerization stability of the secondary polymer (b) in this step largely depends on the performance of the primary polymer (a ′) neutralized with a basic substance as a polymer emulsifier. A carboxyl group-containing monomer is used to make the primary polymer (a) water-soluble, that is, water-soluble or water-dispersed. In the present invention, a pressure-sensitive adhesive layer having good water resistance is formed. The amount of use is reduced as much as possible. This improves the water resistance, but the hydrophilicity of the primary polymer (a ′) obtained by neutralizing the primary polymer (a) is not sufficient. When the aqueous dispersion of the secondary polymer (b) is prepared in the third step while the hydrophilicity of the primary polymer (a ′) is not sufficient, a large amount of aggregates are generated.

  In this case, the amount of the aggregate can be reduced by increasing the amount of the primary polymer (a) to some extent, but the aqueous solution of the secondary polymer (b) having almost the same physical properties as the primary polymer (a). Only a dispersion is obtained. In order to eliminate such problems, a surfactant having one or more radically polymerizable unsaturated groups is used in the third step. As a result, it is possible to stabilize the emulsion polymerization in the third step.

In the present invention, examples of the surfactant having one or more radically polymerizable unsaturated groups used in the third step can be the same as those exemplified in the first step.
The surfactant having one or more radically polymerizable unsaturated groups used in the third step is 0.1% by weight based on 100 parts by weight of all the unsaturated monomers capable of radical polymerization used in the first and third steps. It is important to use 5 to 5.0 parts by weight, and it is more preferable to use 1 to 3 parts by weight. When the amount is less than 0.5 part by weight, the stability of the aqueous dispersion during polymerization is poor and aggregation tends to occur. On the other hand, when the amount is more than 5.0 parts by weight, the stability during polymerization is improved, but the hydrophilic part increases in the secondary polymer (b), and the resulting aqueous dispersion has a high viscosity and a high solid content. An aqueous dispersion cannot be obtained. Furthermore, the surfactant having one or more radical polymerizable unsaturated groups used in the third step is based on 100 parts by weight of the radical polymerizable unsaturated monomer (Y) used in the third step. In such a case, it is preferable to use 0.6 to 6 parts by weight, and it is more preferable to use 1.1 to 3.3 parts by weight.

  In the present invention, the weight ratio (Y) of the radically polymerizable unsaturated monomer (X) provided for the first step and the radically polymerizable unsaturated monomer provided for the third step However, it is preferable that (X) :( Y) = 1: 9 to 2: 8 (weight ratio). In the weight ratio, when the amount of the unsaturated monomer (X) used in the first step is larger than 2: 8, the hydrophilic component having a low molecular weight in the aqueous dispersion of the resulting pressure-sensitive adhesive polymer increases. In other words, the physical properties of the adhesive when used in the adhesive, particularly the water resistance, are adversely affected. If the amount of unsaturated monomer (X) used in the first step is less than 1: 9, the ability to disperse the secondary polymer (b) in the aqueous medium is insufficient, and the polymerization stability during emulsion polymerization is reduced. Sexuality gets worse.

  Water is mentioned as an aqueous medium used for the 1st-3rd process.

  Examples of the initiator used for emulsion polymerization of the primary polymer (a) and the secondary polymer (b) include inorganic peroxide polymerization initiators such as ammonium peroxide and sodium peroxide, and water-soluble azo initiators. Is used. In some cases, oil-soluble initiators such as benzoyl peroxide and azobisisobutyronitrile can be used in combination. These initiators can be used alone, but may be used in a redox type in combination with a reducing agent such as sodium isoascorbate.

Further, during emulsion polymerization, transition metal ions such as copper ions such as cupric sulfate and cupric chloride, and iron ions such as ferrous sulfate and ferric chloride are ^added to the polymerization system at 10 ⁻⁷ to 10 ^−5. It can be added in the range of mol / liter.

  Further, sodium acetate, sodium citrate, sodium bicarbonate, etc. can be used as a buffering agent, and polyvinyl alcohol, water-soluble cellulose derivatives, etc. can be used as protective colloids.

  The particle size of the aqueous dispersion of the pressure-sensitive adhesive polymer produced in the present invention is preferably 5 to 100 nm. The particle size of the aqueous dispersion of the pressure-sensitive adhesive polymer greatly affects the water resistance when used as a pressure-sensitive adhesive. When the particle diameter is larger than 100 nm, the obtained adhesive has low water resistance. Moreover, it is difficult to obtain an aqueous dispersion having a particle diameter of less than 5 nm by a normal method. The particle diameter was measured by a laser light scattering method.

  The aqueous dispersion of the pressure-sensitive adhesive polymer produced in the present invention can be used for various pressure-sensitive adhesives. This pressure-sensitive adhesive has good storage stability, is excellent in roll coat suitability for smoothly coating the surface of the pressure-sensitive adhesive, and is excellent in adhesion, holding power, workability, and water resistance. Specific examples of the pressure-sensitive adhesive include pressure-sensitive adhesives that can be used for various substrates such as paper, film, metal, and cloth. In addition, in aqueous dispersions of adhesive polymers, as thixotropic modifiers such as fine powder silica, antifoaming agents, leveling agents, slip agents, tackifiers, antiseptics, antifungal agents, and film-forming aids These organic solvents may be blended as necessary.

  Hereinafter, the present invention will be described with reference to examples. In the examples, “parts” and “%” indicate “parts by weight” and “% by weight”, respectively.

(Example)
In a reaction vessel equipped with a thermometer, a dropping funnel and a reflux condenser and replaced with nitrogen gas, ion-exchanged water for a reaction tank and a reactive surfactant shown in Table 1 were charged.
Separately, a monomer and a chain transfer agent were mixed in advance as a drop for the first step described in Table 1.
After the internal temperature of the reaction vessel was raised to 80 ° C., ammonium persulfate (hereinafter referred to as APS) was added, and while maintaining the same temperature, the drop for the first step was immediately added at about 3.6 g / 10 min. The solution was added dropwise at a rate and reacted at that temperature for 0.5 hour to obtain an aqueous dispersion of a primary polymer.
Next, 25% aqueous ammonia was added to the obtained aqueous dispersion of the primary polymer, and stirring was continued for 10 minutes to obtain a neutralized aqueous solution of the primary polymer.

Separately, as a drop for the third step, the monomers shown in Table 1, the reactive surfactant, and ion-exchanged water were previously emulsified and mixed to prepare a pre-emulsion.
An initiator composed of perbutyl H (t-butyl hydroperoxide) and erbit N (sodium isoascorbate) shown in Table 1 is added to the neutralized aqueous solution of the primary polymer, and at the same time, about 16 g of the pre-emulsion is added. / 10 minutes, and after completion of the addition, the reaction was continued for 2 hours to obtain an aqueous dispersion of a secondary polymer having a solid content of 50.5%, a viscosity of 800 mPa · s, a pH of 5.8, and a particle size of 60 nm.

Next, an antifoaming agent, a wetting agent and a preservative were added to 200 g of the aqueous dispersion of the secondary polymer obtained based on the composition shown in Table 1, and the pH was adjusted to 7 to 8 with aqueous ammonia. As an imparting resin, 20 parts of Arakawa Chemical Co., Ltd. Superester E-720 was added in solid content. 4 with thickener
The aqueous adhesive was obtained by increasing the viscosity to 500 mPa · s (measured with a BL type viscometer).

(Comparative example)
Secondary polymer in the same manner as in Example except that non-reactive surfactant “RA9612” (manufactured by Nippon Emulsifier Co., Ltd.) was used instead of reactive surfactant “KH-10” used in Example. A water-based pressure-sensitive adhesive was obtained in the same manner as in the following examples.

  Next, the obtained aqueous adhesives of Examples and Comparative Examples were evaluated by the following evaluation test methods. The physical property results of the samples obtained in each test are shown in Table 1.

Evaluation of adhesive (1) Thixotropic index (TI value)
A thixotropic index is obtained by dividing a 6-rotation measurement value by a 60-rotation value using a BL type viscometer and measuring at 60 and 6 rotations using a No. 4 rotor.

(2) Preparation of pressure-sensitive adhesive coated product 2 mil. Coating with an applicator, drying in a drying oven at 105 ° C. for 75 seconds, and a 50 μPET film is applied to obtain a coated adhesive. The coated material was allowed to stand for 24 hours or more in an atmosphere of 23 ° C.-65% RH. 25 mm wide and 10 cm long adhesive coated test specimens are obtained.

(3) SUS permanent adhesive strength evaluation: The release paper of the 25 mm width adhesive coated product test piece was peeled off, the adhesive layer was brought into contact with the SUS plate, a 2 Kg roll was reciprocated once, and left for 24 hours or longer. 180 degrees, 300 mm / min. A tensile test at a speed of

After attaching and leaving to stand for 24 hours or more, 180 degrees, 300 mm / min. A tensile test at a speed of

(4) Evaluation of PE permanent adhesive strength: Peel off the release paper of the 25 mm wide adhesive coated test piece, bring the adhesive layer into contact with the polyethylene plate, and reciprocate the 2 kg roll once (5) Holding power: 25 mm above Remove the release paper of the width adhesive coated product test piece, contact the adhesive layer with the SUS plate so that the application area is 25 x 25 mm, apply 2Kg roll 1 reciprocation, and leave it at 40 ° C for 20 minutes The weight of 1 kg is lowered and the test is conducted at 40 ° C. for 20 hours, and when it falls or does not fall, the deviation length is measured.

(6) Workability: After applying a load of 20 kg / cm ² for 3 days with the 25 mm width adhesive coated specimen test piece attached, the degree of protrusion of the adhesive is visually evaluated.
A: Good.
○: A level with no practical problem.
Δ: Slightly problematic level.
X: It is bad.

(7) Water resistance: A 25 × 100 mm pressure-sensitive adhesive coated product test piece is immersed in warm water at 60 ° C. for 3 days, and the degree of whitening is visually evaluated.
A: Good.
○: A level with no practical problem.
Δ: Slightly problematic level.
X: It is bad.

  The comparative example is an example using a non-reactive surfactant, but the adhesive strength and processability were remarkably inferior.

Claims (5)

In an aqueous medium, radical polymerization is possible including 0.5 to 10% by weight of a carboxyl group-containing monomer when the total amount of unsaturated monomers subjected to the following first and third steps is 100% by weight. 0.5 to 5.0 parts by weight of the chain transfer agent and 100 parts by weight of the total unsaturated monomers. A first step of obtaining an aqueous dispersion of the primary polymer (a) by emulsion polymerization using a surfactant having one or more radically polymerizable unsaturated groups of 0.05 to 1.0 parts by weight;
A basic substance is added to the aqueous dispersion of the primary polymer (a) to neutralize the primary polymer (a) to obtain an aqueous solution or aqueous dispersion of the primary polymer (a ′). Steps; and
A non-aromatic radically polymerizable unsaturated monomer (Y), a surfactant having one or more radically polymerizable unsaturated groups, and an aqueous medium are mixed, and the mixture is mixed with the primary polymer ( a third step of obtaining an aqueous dispersion of the secondary polymer (b) by emulsion polymerization in addition to the aqueous solution or aqueous dispersion of a ′)
And the amount of the surfactant having one or more radically polymerizable unsaturated groups provided in the third step is 100 parts by weight of the total unsaturated monomers provided in the first and third steps. The manufacturing method of the aqueous dispersion of the polymer for aqueous adhesives which is 0.5-5.0 weight part with respect to this. The weight ratio of the radically polymerizable unsaturated monomer (X) provided for the first step to the radically polymerizable unsaturated monomer (Y) provided for the third step is (X) The manufacturing method according to claim 1, wherein: (Y) = 1: 9 to 2: 8. An aqueous dispersion of a polymer for aqueous pressure-sensitive adhesives produced by the production method according to claim 1 or 2. The aqueous dispersion according to claim 3, wherein the particle size of the aqueous dispersion of the aqueous adhesive polymer is 5 to 100 nm. An aqueous pressure-sensitive adhesive comprising the aqueous dispersion according to claim 3 or 4.