JP2002146315A - Aqueous contact adhesive composition and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous contact adhesive composition which is an aqueous system having a high drying rate and capable of increasing the resin content having an excellent adhesive strength in a semidried state without damaging the environment and without any risk of a fire and to provide a method for producing the aqueous contact adhesive composition. SOLUTION: This aqueous contact adhesive composition comprises an aqueous emulsion containing (A) and alkyl acrylate resin having <=0 deg.C glass transition temperature, (B) a urethane resin and (C) a tackifier having 70-180 deg.C softening point and is obtained by including the component (B) in an amount of 2-30 pts.wt. and the component (C) in an amount of 1-30 pts. wt. based on 100 pts.wt. of the component (A).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an aqueous contact adhesive composition and a method for producing the same.

[0002]

2. Description of the Related Art It has been known that a conventional water-based contact adhesive is prepared by forming a tackifier resin into a resin emulsion of about 50% and blending it with a polymer emulsion such as chloroprene rubber latex. The adhesive obtained by this formulation has a non-volatile content of about 50%, and the drying speed is slow because the solvent is water. Further, since an emulsifier for resin emulsification is further added to the emulsifier in the polymer emulsion, the adhesive performance is adversely affected, and the initial bonding speed is lower and the bonding strength is lower than that of the solvent-based adhesive. In contrast, JP-A-8-337765 discloses that
Low moisture adhesives are disclosed. This adhesive is
Tackifying resin with high acid value in the presence of alkaline substance,
At least in the pH range of 6.5 to 8.0, a stable chloroprene latex alone or directly added to a mixture of chloroprene latex and another polymer emulsion without previously dissolving in a solvent, and dissolved in these liquids It is obtained by doing. This makes it possible to obtain an aqueous adhesive having a high resin content without newly adding an emulsifier.

[0003]

However, an adhesive having a low moisture content can be obtained by the above method, but the tackifying resin having a high acid value is made water-soluble with an alkaline substance.
The water retention of the resin is increased due to the increased water retention during drying, and the drying speed is slow compared to the high non-volatile content. As a result, the drying speed, which is a drawback of the aqueous adhesive, and the initial bonding speed are slow. Cannot be improved.

Accordingly, the present invention improves on the above-mentioned disadvantages of the prior art, and is an aqueous system which does not harm the environment and does not cause fire, has a high drying speed, and has excellent adhesive strength in a semi-dry state. It is an object of the present invention to provide an aqueous contact adhesive capable of increasing the resin content, and a method for producing the same.

[0005]

The present invention provides an alkyl acrylate resin (A) and a urethane resin (B) having a glass transition temperature of 0 ° C. or less, and a tackifier having a softening point of 70 to 180 ° C. Aqueous contact adhesive comprising an aqueous emulsion containing (C) and containing 2 to 30 parts by weight of component (B) and 1 to 30 parts by weight of component (C) based on 100 parts by weight of component (A). This problem was solved by providing an agent composition.

Since an aqueous emulsion containing each of the above-mentioned components is used, the aqueous contact adhesive composition has a high drying speed, excellent initial adhesive strength, and particularly excellent performance in adhesiveness to a PVC sheet, a plasticizer, and weather resistance. You can get things.

[0007]

Embodiments of the present invention will be described below. In this specification, “(meth) acrylic acid”
And the like represent "acrylic acid and methacrylic acid".

The aqueous contact adhesive composition according to the present invention comprises an alkyl acrylate resin (A) having a glass transition temperature of 0 ° C. or lower, a urethane resin (B),
It consists of an aqueous emulsion containing a tackifier (C) having a softening point of -180 ° C.

The above-mentioned alkyl acrylate resin (hereinafter abbreviated as “component (A)”) has a glass transition temperature (Tg) of 0 ° C. or less. When Tg is higher than 0 ° C., the adhesive strength at ordinary temperature and low temperature decreases.

On the other hand, if the Tg is too low, the adhesion at low temperatures is excellent, but the holding power at high temperatures decreases. Therefore, the lower limit of Tg is -90 ° C, and the preferred Tg is -70 ° C.
-10 ° C. In addition, the glass transition temperature described here means a value calculated by the following equation (1). In addition, for example, when using an alkyl acrylate resin in which urethane and rosin are combined as seed particles, the Tg of the alkyl acrylate portion may satisfy the above condition.

1 / Tg = Wa / Tga + Wb / Tgb + (1) (wherein Tg is the glass transition temperature (K) of the copolymer, T
ga and Tgb indicate the glass transition temperature of the homopolymer of the monomers a and b, respectively, and Wa and Wb indicate the weight fractions of the monomers a and b, respectively. The component (A) includes an alkyl acrylate having an alkyl group having 2 to 12 carbon atoms (hereinafter abbreviated as “component (a1)”), a carboxyl group-containing radically polymerizable unsaturated monomer. (Hereinafter abbreviated as “component (a2)”), a radical polymerizable unsaturated monomer copolymerizable with each of the unsaturated monomers of components (a1) and (a2) (hereinafter, referred to as “component (a3) ) ") Is preferably used.

Each component (a1) constituting the component (A)
The copolymerization ratio of (a2) and (a3) is such that component (a1)
The ratio is preferably such that 99 parts by weight, component (a2) is in the range of 0.5 to 5 parts by weight, and component (a3) is in the range of 0.1 to 29 parts by weight, and component (a1) is in the range of 75 to 95 parts by weight. The ratio is preferably such that (a2) is in the range of 1 to 4 parts by weight and component (a3) is in the range of 1 to 20 parts by weight. When the component (a1) is less than 60 parts by weight, sufficient adhesive strength may not be obtained,
On the other hand, when the amount is more than 99 parts by weight, a sufficient holding force at a high temperature may not be obtained. That is, the component (a1)
Has a function of lowering the Tg of the obtained copolymer and imparting an initial tack. When the amount of the component (a2) is less than 0.5 part by weight, the adhesive strength and the cohesive strength of the polymer may not be sufficiently obtained. When the amount is more than 5 parts by weight, the water resistance of the adhesive composition tends to decrease. There is. When the amount of the component (a3) is less than 1 part by weight, the cohesive strength of the polymer may not be obtained, and the holding power at a high temperature may decrease. When the amount is more than 20 parts by weight, the adhesive force and the initial tack may decrease. Tend.

Specific examples of the component (a1) include ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, lauryl acrylate, and the like. May be used.

Specific examples of the component (a2) include α, β-unsaturated carboxylic acids such as acrylic acid and methacrylic acid, and α, β-unsaturated acids such as itaconic acid, maleic acid and 2-methylene glutaric acid. And a saturated dicarboxylic acid.
These may be used in combination of two or more.

Specific examples of the component (a3) include aromatic vinyl compounds such as styrene and α-methylstyrene;
Methyl (meth) acrylate, ethyl methacrylate,
Alkyl (meth) acrylates other than (a1) such as butyl methacrylate, 2-hydroxyethyl (meth)
Monomers having a glycidyl group such as (meth) acrylate containing terminal hydroxy group, glycidyl (meth) acrylate, allyl glycidyl ether, such as acrylate and 4-hydroxybutyl (meth) acrylate;
(Meth) acrylamide, N-alkylolacrylamide, (meth) acrylonitrile, vinyl acetate, vinyl esters such as vinyl propionate, vinyl halide and the like. In addition to the above, one such as allyl (meth) acrylate, ethylene glycol di (meth) acrylate, and trimethylolpropane triacrylate.
A crosslinkable monomer having two or more radically polymerizable double bonds in the molecule can also be used.

As the component (a3), a high Tg monomer such as methyl methacrylate, acrylamide and acrylonitrile, and a cross-linking such as glycidyl (meth) acrylate for increasing the Tg of the obtained copolymer to impart cohesion. The reactive monomer is preferred. Among them, glycidyl (meth) acrylate is preferred because it has a large effect of improving the adhesive strength. The above monomers may be used in combination of two or more.

The component (B) is not particularly limited, but is an anionic self-emulsifying urethane resin (water-dispersible urethane resin) which can be emulsified (emulsified) without using an external surfactant. In addition, a water-dispersible urethane resin having high crystallinity and high initial adhesive strength and high adhesive speed is preferred from the viewpoint of adhesiveness. Many such water-dispersible urethane resins are commercially available, and specific examples thereof include “NeoRez” series, a product name of Zeneca Corporation,
Sumitomo Bayer Urethane product name “Disperco
11 "series.

The component (C) preferably has a softening point of 70 to 180 ° C, preferably 100 to 170 ° C.
When the softening point is lower than 70 ° C., the initial tack may be obtained, but the holding power at a high temperature may be lacking. On the other hand, when the softening point is higher than 180 ° C., the initial tack may decrease.

Specific examples of the component (C) include rosin resins, terpene resins, and petroleum resins. These can be dispersed in water with an emulsifier. Among them, a rosin-based resin, particularly a disproportionated rosin, a polymerized rosin, or a rosin derivative resin emulsion obtained by reacting a disproportionated rosin or a polymerized rosin with a polyhydric alcohol (glycerin, pentaerythritol, or the like) is preferable.

Specific examples of the component (C) that can be suitably used in the present invention include “Superester E-720, E-740” (trade name, manufactured by Arakawa Chemical Co., Ltd.) (softening point 100 ° C.).
Trade name “Superester E-730-55” (softening point 125 ° C.), trade name “Superester E-650, E
-865 "(softening point 160 ° C) and" SK-130D "(softening point 138 ° C) manufactured by Harima Chemicals, Inc.

In the present invention, for the purpose of adjusting the molecular weight of the copolymer, it is possible to add an alkyl mercaptan or the like as a molecular weight modifier during the polymerization.
Further, the composition of the present invention, depending on its intended use, a crosslinking agent, a penetrant, a film forming aid, an antifoaming agent, a rust inhibitor, an ultraviolet absorber, a light stabilizer, a pigment, silica, etc. It is also possible to mix inorganic fillers and the like. The cross-linking agent is used for improving the cohesive strength, and for example, a conventionally known polyfunctional isocyanate-based cross-linking agent or polyfunctional epoxy-based cross-linking agent can be used.

The aqueous contact adhesive composition according to the present invention comprises an aqueous emulsion containing the components (A) to (C). It is preferable that 2 to 30 parts by weight of the component (B) and 1 to 30 parts by weight of the component (C) are contained in 100 parts by weight of the component (A), and 5 to 25 parts by weight of the component (B), It is preferable to contain 3 to 25 parts by weight. When the amount of the component (B) is less than 2 parts by weight, the cohesive strength of the film may be reduced. When the amount is more than 30 parts by weight, the adhesive strength and the initial tack may be reduced. Component (C) is 1
If the amount is less than 30 parts by weight, it may be difficult to obtain a sufficient adhesive strength and an initial tack.
The heat resistance and the water resistance of the film may decrease.

The total amount of the components (A) to (C) in the aqueous emulsion is preferably 40 to 70% by weight.
0-70% by weight is preferred. If the total amount of the above components is less than 40% by weight, the time required for drying may increase, and if it exceeds 70% by weight, the viscosity may be too high and the coating aptitude may be lacking.

Next, a method for producing the aqueous contact adhesive composition of the present invention will be described. In the present invention, aqueous emulsification can be performed according to a known method. For example, the above components (A) to (C) can be produced by mixing and emulsifying in the presence of a surfactant, if necessary, or acrylic acid as a raw material of the component (A) can be produced. It can also be produced by emulsion polymerization of an alkyl ester monomer in the presence of the component (B) and the component (C).

When a copolymer comprising the above-mentioned components (a1) to (a3) is used as the component (A), an aqueous emulsion containing the above-mentioned copolymer is prepared in advance according to the method described below. The adjusting method is suitably adopted. The above-mentioned optional components may be added to the aqueous emulsion as needed.

As a method for preparing an aqueous emulsion containing a copolymer as described above, for example, each component (a1)
In addition to emulsion polymerization and suspension polymerization of (a3), a method of removing an organic solvent under reduced pressure after solution polymerization in an organic solvent and making the aqueous solution by phase inversion may be employed. Among them, a method of emulsion polymerization in an aqueous medium in the presence of a surfactant or a protective colloid is preferable. Emulsion polymerization is carried out according to a conventional method, and in that case, a polymerization initiator and a surfactant are usually used.

Examples of the polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, peroxides such as hydrogen peroxide, benzoyl peroxide and t-butyl hydroperoxide, and azoisobutyronitrile. Are used. Further, a redox-type initiator obtained by combining the above-mentioned polymerization initiator with a reducing agent such as ascorbic acid or Rongalit can also be used. Further, these initiators may be used in plural combinations as necessary. The amount of the initiator used is 10
0.01 to 5 parts by weight, preferably 0.1 to 5 parts by weight with respect to 0 parts by weight.
2 parts by weight are preferred.

Examples of the surfactant include anionic surfactants such as alkyl benzene sulfonate, higher alcohol sulfate, and polyoxyethylene alkyl sulfonate, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether and the like. And nonionic surfactants and cationic surfactants. Among them, in order to improve the water resistance of the adhesive film, it is preferable to use a so-called reactive surfactant having a radical polymerizable unsaturated bond in the molecule.

The main reactive surfactants include sodium alkyl allyl sulfosuccinate (trade name “Eleminol JS-2” manufactured by Sanyo Kasei Co., Ltd., “Latemul S-180” manufactured by Kao Corporation), methacryloyloxy polyoxyalkylene. Sodium sulfate (trade name "Eleminol RS-30" manufactured by Sanyo Kasei Co., Ltd.), polyoxyethylene alkyl allyl phenol ether (trade name "Aqualon RN-20" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), polyoxyethylene alkyl allyl phenol ether sulfate Salt (Aqualon HS-10, trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Adecaria Soap SE-10, trade name, manufactured by Asahi Denka Kogyo KK) and the like. These surfactants may be used in plural combinations as necessary.

In the present invention, it is possible to polymerize by adding a water-soluble polymer compound such as polyvinyl alcohol and hydroxyethyl cellulose as a protective colloid as well as a surfactant. The amount of the surfactant or protective colloid used is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the radically polymerizable unsaturated compound used.
-5 parts by weight is preferred.

In particular, in the present invention, as a method for producing an aqueous contact adhesive composition, a reactive surfactant having a radically polymerizable unsaturated group in the presence of a urethane resin and a water-dispersible tackifier is used. The radical polymerizable unsaturated monomer (components (a1) to (a)
The method of emulsion polymerization of 3)) is recommended. According to such a method, an aqueous contact adhesive composition containing a composite aqueous emulsion of acrylic / urethane / tackifier resin is obtained.

In the production of the aqueous contact adhesive composition of the present invention, the reaction conditions in the case of using the emulsion polymerization method are not particularly limited, but the reaction temperature is from 40 to 40.
95 ° C is preferable, and 50 to 85 ° C is preferable. The reaction time is preferably 1 to 12 hours, and more preferably 2 to 8 hours.

The aqueous contact adhesive composition obtained according to the present invention is widely used in the fields used at construction sites, such as for building interiors, in the industrial fields, such as housing building materials and vehicle interiors, and in fields used in ordinary households. It can be used in the field of application of the solvent-based adhesives used, does not harm the environment, has no danger of fire, has a fast drying speed, and has excellent initial adhesive strength, plasticizer resistance, and weather resistance.

[0034]

EXAMPLES Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Further, “parts” and “%” described in the examples are “parts by weight” and “% by weight” unless otherwise specified.

<Preparation of Aqueous Emulsions of Acrylic Resin (1) to (13)> In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, and a dropping funnel, a water-dispersed urethane resin (a product of Sumitomo Bayer Urethane Co., Ltd.) The name “Dispacoll U-53”, hereinafter abbreviated as “U-53.” 20 parts of solid content 40% by weight, water-dispersed rosin resin (trade name “Superester E-740” manufactured by Arakawa Chemical Co., Ltd.) Hereinafter, "E
−740 ”. 20 parts by weight (solid content: 50% by weight) and heated to 75 ° C. After 0.3 parts of azoisobisbutyronitrile was added into the reaction vessel, an emulsion (pre-emulsion) separately prepared as described below was added dropwise over 5 hours.

The above-mentioned pre-emulsion comprises 91 parts of n-butyl acrylate (hereinafter abbreviated as “n-BA”),
5 parts of acrylonitrile (hereinafter abbreviated as “AN”),
Glycidyl methacrylate (hereinafter abbreviated as "GMA") 3 parts, acrylic acid (hereinafter abbreviated as "AA")
1 part, surfactant name “AQUALON HS-1”
The mixture was prepared by mechanically emulsifying a mixture of 2 parts of “0” (pure product) and 25 parts of water with a homomixer in advance.

After dropping the pre-emulsion, 0.45 parts of t-butyl hydroperoxide was added, and the mixture was further reacted at 75 ° C. for 2 hours and cooled, and the non-volatile milky acrylic resin (acrylic / urethane / rosin resin) was added. 70%
Thus, an aqueous emulsion (1) was obtained.

Aqueous emulsions of acrylic resins (2) to (1) were emulsion polymerized in the same manner as described above with the compositions shown in Table 1.
3) was prepared.

The numerical values in Table 1 indicate the solid content conversion amount. The abbreviations of “monomer” and “seed particles” in Table 1 are shown in Table 2 below.

[0040]

[Table 1]

[0041]

[Table 2]

(Examples 1 to 9 and Comparative Examples 1 to 4) Each of the obtained aqueous emulsions was evaluated as described below. Table 3 shows the results.

Preparation of Test Pieces A PVC sheet and a slate plate were used as base materials. First, an adhesive was applied to a slate plate and a PVC sheet using a brush (application amount: 200 g / m ² ). After application, room temperature (20
(30 ° C, 65% RH) for 30 minutes (open time)
did. Next, the application surfaces are stuck together, and their own weight is 5 kg.
2 hand rollers were reciprocated and pressed.

Evaluation method Evaluation method is JIS A5536 (adhesive for vinyl flooring)
It went according to. (1) Drying speed It was applied to the surface of the PVC sheet at the time of preparation of the test piece, and it was determined whether or not a transparent film had formed after being left for an open time of 30 minutes. The criteria are as follows. ：: Dry transparent film formed state △: Semi-dried partially film formed state ×: Undried and not formed film state After 5 minutes, a pulling speed of 200 mm / min.
A 90-degree peeling test with a width of 5 mm was performed. At the same time as measuring the strength, the state of destruction was also observed. (3) Normal 90-degree peeling strength A 90-degree peeling test was carried out 7 days after curing at room temperature in the same manner as described above. (4) 90 degree peeling strength after heat aging 7 days after curing at room temperature and 7 days after standing in 70 ° C oven
After taking out and cooling to room temperature, a 90-degree peeling test was performed in the same manner as described above.

The numbers in Table 3 indicate the peeling strength (N / 25 mm) in each test, and the alphabets indicate the breaking states shown in Table 4. At this time, the preferable state of destruction is as follows. Good ← G (or F)> GA, A> AF → Poor

[0046]

[Table 3]

[0047]

[Table 4]

(Comparative Examples 5 and 6) The same test as described above was conducted using a commercially available chloroprene latex-based aqueous contact product (nonvolatile content: 70%) and a commercially available chloroprene solvent type product (nonvolatile content: 25%). Table 3 shows the results.

[0049]

According to the present invention, there is provided an aqueous contact adhesive composition having a high drying speed, an initial adhesive strength, and particularly excellent adhesiveness to a PVC sheet, a plasticizer, and excellent weatherability. The industrial value of the present invention is significant.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toru Miyahara 1-13, Shododa, Hirakata-shi, Osaka Central Rika Kogyo Co., Ltd. F-term (reference) 4J040 BA202 DF041 EF002 JA03 KA26 LA02 LA08

Claims (5)

[Claims] 1. An aqueous emulsion containing an alkyl acrylate resin (A) having a glass transition temperature of 0 ° C. or lower, a urethane resin (B), and a tackifier (C) having a softening point of 70 to 180 ° C. An aqueous contact adhesive composition comprising: 2 to 30 parts by weight of component (B) and 1 to 30 parts by weight of component (C) based on 100 parts by weight of component (A). 2. The component (A) having 2 to 12 carbon atoms.
Acrylic acid alkyl ester having an alkyl group (a)
1) 60 to 99 parts by weight, 0.5 to 5 parts by weight of a carboxyl group-containing radically polymerizable unsaturated monomer (a2), component (a)
The aqueous contact according to claim 1, which is a copolymer of 0.1 to 29 parts by weight of a radical polymerizable unsaturated monomer (a3) copolymerizable with each of the unsaturated monomers of (1) and (a2). Adhesive composition. 3. The aqueous contact adhesive composition according to claim 1, wherein the component (B) is an anionic self-emulsifying urethane resin. 4. The component (C) is a disproportionated rosin, a polymerized rosin, or a rosin derivative resin emulsion obtained by reacting a disproportionated rosin or a polymerized rosin with a polyhydric alcohol. Aqueous contact adhesive composition according to any one of claims 1 to 3. 5. The components (A), (B) and (C)
Of an aqueous contact adhesive composition by emulsion polymerization of a polymer in the presence of a reactive surfactant having a radically polymerizable unsaturated group.