JP2001026756A - Water-based adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-based adhesive consisting essentially of a polychloroprene latex, an inorganic filler and a titanate-based coupling agent and excellent in heat resistance. SOLUTION: This water-based adhesive comprises (A) a polychloroprene latex, (B) an inorganic filler, e.g. aluminum hydroxide and (C) a titanate-based coupling agent. In this case, the amounts of the components based on 100 pts.wt. of the component (A) and expressed in terms of solid are 1-80 pts.wt. of the component (B) and 0.001-10 pts.wt. of the component (C).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based adhesive which can be used as an adhesive for transportation interiors and footwear, and which exhibits excellent heat resistance especially in bonding rubber or plastic.

[0002]

2. Description of the Related Art Conventionally, as a polychloroprene-based adhesive, a solvent-based adhesive produced by dissolving chloroprene rubber in an organic solvent has been mainly used. However, in recent years, there has been a concern about the danger of fire and environmental pollution caused by organic solvents during the production and use of solvent-based adhesives, and the demand for solvent removal is increasing year by year. As a means for removing the solvent, a method in which the solvent-based adhesive is replaced with a water-based adhesive based on polychloroprene latex is effective. Aqueous adhesives using polychloroprene latex are used in a wide variety of applications, such as for building materials, houses, interiors of transports, furniture, and footwear. However, when rubber or plastic is used as the adherend, heat resistance is insufficient, and there is a possibility that poor adhesion may occur in applications where stress is applied at high temperatures. Conventionally, this problem has been improved by a method of combining and combining a silane coupling agent and an inorganic filler, but it has been insufficient as an improvement in heat resistance.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous adhesive which exhibits sufficient heat resistance even when used for bonding rubber or plastic materials.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the polychloroprene latex, the inorganic filler, and the titanate-based coupling agent are essential components. As a result, an aqueous adhesive exhibiting high heat resistance was invented.

Hereinafter, the contents of the present invention will be described in detail. The polychloroprene water-based adhesive in the present invention is a water-based adhesive containing a polychloroprene latex. This polychloroprene latex is 2-chloro-1,3
A latex containing, as a main component, a homopolymer of butadiene (hereinafter, referred to as chloroprene) or a copolymer obtained by emulsion-copolymerizing chloroprene and one or more monomers copolymerizable with chloroprene.

Examples of monomers copolymerizable with chloroprene include 2,3-dichloro-1,3-butadiene,
-Chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, acrylic acid and its esters, methacrylic acid and its esters, and the like, and if necessary, two or more kinds may be used. However, a copolymer with a carboxyl group-containing vinyl monomer, for example, methacrylic acid, acrylic acid, crotonic acid, fumaric acid, maleic acid, citraconic acid, glutaconic acid or the like is preferable. In particular, among them, a copolymer with methacrylic acid (also referred to as 2-methylpropenoic acid or α-methylacrylic acid) can give the adhesive a high normal adhesion performance.

The emulsifier and / or dispersant used in the emulsion polymerization of polychloroprene latex in the present invention is not particularly limited, and various anionic, nonionic and cationic types can be used. Examples of the emulsifier used for the anionic latex include a carboxylic acid type and a sulfate type. Examples thereof include alkali metal salts of rosin acid, alkyl sulfonates having 8 to 20 carbon atoms, alkyl aryl sulfates, sodium naphthalene sulfonate and formaldehyde. And the like. Specific examples of the nonionic type include a water-soluble polymer, an ether type, an ester type, a sorbitan ester type, a sorbitan ester ether type, an alkylphenol type and the like.For example, polyvinyl alcohol, polyoxyethylene tridecyl ether, polyoxyethylene mono Stearate,
Sorbitan monooleate and the like can be mentioned.

Specific examples of the cationic type include an aliphatic amine salt, an aliphatic quaternary amine salt, an aromatic quaternary ammonium salt and a heterocyclic quaternary ammonium salt. Examples thereof include octadecyltrimethylammonium chloride and hexadecyltrimethyl. Ammonium chloride, dodecyltrimethylammonium chloride, dilauryldimethylammonium chloride and the like can be mentioned. However, an anionic latex using an alkali metal salt of rosin acid can impart high heat resistance to the aqueous adhesive of the present invention.

The amount of the emulsifier and / or dispersant used in the emulsion polymerization of the polychloroprene latex in the present invention is preferably from 1 part by weight to less than 20 parts by weight based on 100 parts by weight of the initially charged chloroprene monomer. is there. 1
When the amount is less than 20 parts by weight, the emulsifying power is insufficient, and when the amount is more than 20 parts by weight, when the obtained polychloroprene latex is used as an adhesive, the adhesive strength is reduced.

[0010] The aqueous adhesive of the present invention is prepared by adding an inorganic filler and a titanate-based cup to an emulsion polymerization solution (ie, polychloroprene latex) containing the above-mentioned chloroprene polymer obtained by emulsion polymerization according to the method exemplified below. It can be obtained by including a ring agent. The method for polymerizing the chloroprene polymer in the present invention is not particularly limited, and a polymerization temperature, a polymerization catalyst, a chain transfer agent, a polymerization terminator, a final polymerization rate, demonomerization, concentration conditions, and the like are appropriately selected and controlled. This makes it possible to adjust the solid content concentration, the molecular weight of the toluene-soluble portion, the toluene-insoluble content (gel content), and the like.

The polymerization temperature for producing the chloroprene polymer in the present invention is not particularly limited, but the polymerization temperature is preferably from 0 to 50 in order to smoothly carry out the polymerization reaction.
It is preferably set to ° C. The polymerization catalyst is a sulfated salt such as potassium persulfate, an organic peroxide such as tert-butyl hydroperoxide, or the like, and is not particularly limited.

The type of the polychloroprene chain transfer agent is not particularly limited, and those usually used for emulsion polymerization of chloroprene can be used. For example, long-chain alkyl mercaptans such as n-dodecyl mercaptan and tert-dodecyl mercaptan, dialkyl xanthogen disulfides such as diisopropylxanthogen disulfide and diethylxanthogen disulfide, and known chain transfer agents such as iodoform can be used. The chain transfer agent can be added not only during the preparation but also during the polymerization.

The polymerization terminator (polymerization inhibitor) for polychloroprene is not particularly limited.
rt-butyl-4-methylphenol, phenothiazine, hydroxyamine and the like can be used.

The final polymerization rate of polychloroprene is not particularly limited and can be adjusted arbitrarily. Unreacted monomers are removed by a demonomerization operation.
The method is not particularly limited. Concentrate or
By diluting with addition of water or the like, the solid content concentration can be controlled to a necessary concentration. Examples of the method for concentration include concentration under reduced pressure, but are not particularly limited. But,
In order to increase the drying speed of the adhesive, the solid concentration of the polychloroprene latex in the present invention is preferably 50% by weight or more.

The inorganic filler in the present invention is an inorganic filler.
Chemical composition, mineral composition, particle shape (needle, sphere,
, Plate, amorphous, porous, etc.), particle size (average particle
Size, particle size distribution, etc.), manufacturing method (natural mineral grinding method, chemical
Refining method or synthetic method), locality, geological classification, etc.
Properties (purity, specific gravity, bulk specific gravity, density, bulk density, water content,
Hue, etc.), without particular limitation,
Compounds, carbonates, sulfates, silicates, nitrides, carbons, etc.
Seed inorganic fillers can be used. As a specific example of the oxide,
Silica, diatomaceous earth, alumina, zinc oxide, rutile type oxide
Tan, anatase type titanium oxide, amorphous titanium oxide, acid
Calcium oxide, magnesium oxide, iron oxide, tin oxide, acid
Antimony chloride, ferrites and the like. Hydroxylation
As a specific example of the product, calcium hydroxide (chemical formula Ca
(OH)_Two), Magnesium hydroxide (chemical formula Mg (O
H)_Two), Aluminum hydroxide (chemical formula Al (O
H)_Three), Basic magnesium carbonate and the like.
Specific examples of carbonates include calcium carbonate,
Gnesium, zinc carbonate, barium carbonate, dawsonite,
Natural hydrotalcite (general formula [Mg₆Al_Two(OH)
₁₆] [CO_Three・ 4H_TwoO]), synthetic hydrotalcite
And so on. Specific examples of sulfates include calcium sulfate
, Barium sulfate, gypsum fiber and the like. Silicic acid
Specific examples of salts include calcium silicate (Wollastonite).
G (general formula CaSiO_Three), Zonolite), talc (one
General formula 4SiO_Two・ 3MgOH_TwoO), Hard clay, S
Soft clay, feldspar (general formula NaAlSi_ThreeO₈, CaAl
_TwoSi_TwoO₈, KAlSi_ThreeO₈), Mica, montmorillona
Ito (general formula Al_3.33Mg_0.67(Si₈O₂₀) (OH)_Four
+ 0.67Na), pyrophyllite (general formula Al
_Four(Si₈O₂₀) (OH)_Four), Bentonite, activated white
Soil, sepiolite (general formula Mg₈Si ₁₂O₃₀(OH)
_Four(OH_Two)_Four・ 8H_TwoO), imogolite, hextry
G, sericite (general formula K_TwoO.3Al_TwoO_Three・ 6SiO_Two
・ 2H_TwoO), glass fiber, glass beads, silas bal
And the like. Specific examples of nitride include nitride nitride.
Luminium, boron nitride, silicic acid nitride and the like can be mentioned.
Specific examples of carbons include carbon black, graphite
Site, carbon fiber, carbon balun, charcoal powder, etc.
You. Other inorganic fillers include various metals (lead, copper,
Powder of iron, zinc, etc., potassium titanate (general formula K_Two
O ・ nTiO_Two, N = 1, 2, 4, 6, 8), basic sulfur
Magnesium phosphate (general formula MgSO_Four・ 5Mg (OH)_Two・
3H_TwoO), lead zirconate titanate, aluminum bore
Metal, molybdenum sulfide, silicon carbide, stainless steel fiber,
Examples include zinc oxalate and slag fiber. In the present invention
Hydroxides or silicates are preferred as inorganic fillers.
No. Hydroxide or silicate exhibits sufficient heat resistance
Can be done. More preferably aluminum hydroxide
And a water-based adhesive with excellent adhesion balance.
Can be

In the present invention, the inorganic filler includes a silane coupling agent, an aluminum-based coupling agent, a fatty acid,
The surface may be treated with a surface treating agent such as fats and oils, nonionic surfactants and waxes. However, in order to efficiently perform the treatment with the titanate-based coupling agent and to exhibit higher heat resistance, it is preferable not to perform the surface treatment with a reagent other than the titanate-based coupling agent.

The inorganic filler in the present invention may be a mixture of two or more inorganic fillers or an organic filler (for example,
A mixture of rubber powder, wood powder, Teflon powder, fibers such as aramid, etc.), or may be added as an emulsion with an emulsifier or dispersant. However, if the filler is added as an emulsion, the amount of the emulsifier or dispersant contained in the adhesive will increase, and the solid content and viscosity of the adhesive will decrease, resulting in lower adhesive strength. There is fear. Therefore, it is preferable to add the powder as it is.

The amount of the inorganic filler to be added is 1 to 100 parts by weight of the solid content of polychloroprene latex.
~ 80 parts by weight are preferred. When the amount is less than 1 part by weight, the heat resistance becomes insufficient. When the amount exceeds 80 parts by weight, the viscosity of the adhesive becomes high, which adversely affects the coating property, and the initial adhesive strength and the normal adhesive strength decrease. Or When the inorganic filler is added as an emulsion, the above addition amount indicates the amount of solid content.

The titanate coupling agent in the present invention is not particularly limited, and various amine type, phosphorous acid type, pyrophosphoric acid type, carboxylic acid type and sulfonyl type can be used alone or in combination. . Specific examples of the amine-type titanate-based coupling agent include isopropyl tri (N-aminoethyl-aminoethyl) titanate. Specific examples of the phosphorous acid type titanate coupling agent include tetraisopropylbis (dioctylphosphite) titanate, tetraoctylbis (ditridecylphosphite) titanate, tetra (2,2)
-Diallyloxymethyl-1-butyl) bis (di-tridecyl) phosphite titanate; Specific examples of the pyrophosphoric acid type titanate coupling agent include:
Isopropyl tris (dioctyl pyrophosphate) titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, bis (dioctyl pyrophosphate) ethylene titanate and the like can be mentioned. Specific examples of the carboxylic acid type titanate coupling agent include isopropyl triisostearoyl titanate. Specific examples of the sulfonyl-type titanate coupling agent include isopropyl tri-n-dodecylbenzenesulfonyl titanate.

The method of adding the titanate-based coupling agent in the present invention is not particularly limited, and can be added by an integral blend method, a dry treatment method, a wet treatment method, or the like. The integral blending method is a method of directly adding and mixing a titanate-based coupling agent when mixing materials (for example, a filler, a tackifier resin, and a thickener) constituting an adhesive. In the dry treatment method, a titanate-based coupling agent or a titanate-based coupling agent solution (a solution of the titanate-based coupling agent dissolved in water or an organic solvent) is added dropwise or sprayed while stirring the inorganic filler, This is a method of obtaining an inorganic filler which has been previously treated with a titanate-based coupling agent after being stirred to be uniform and then dried. That is, this is a method in which an inorganic filler treated with a titanate coupling agent is prepared, and the filler is added to an adhesive or an adhesive composition to add the titanate coupling agent. The wet treatment method is to add an inorganic filler to water or an organic solvent to form a slurry, add a titanate-based coupling agent with stirring, stir so as to be uniform, and then dry the titanate-based coupling agent. Is a method of obtaining an inorganic filler which has been treated in advance. Similar to the dry treatment method, a method of adding a titanate-based coupling agent by preparing an inorganic filler treated with a titanate-based coupling agent and adding the filler to an adhesive or an adhesive composition. is there. As a method of adding the titanate-based coupling agent, a dry method or a wet method that can efficiently improve heat resistance with a small amount of addition is preferable. In the integral blend method, the required amount of the titanate-based coupling agent increases, which may be economically disadvantageous.

The addition amount of the titanate coupling agent in the present invention is preferably 0.001 to 10 parts by weight of the titanate coupling agent per 100 parts by weight of the solid content of the polychloroprene latex. When the amount is less than 0.001 part by weight, the heat resistance is not sufficiently improved, and when it exceeds 10 parts by weight, it is economically disadvantageous. The commercially available titanate-based coupling agent may contain an organic solvent in addition to the titanate compound as the active ingredient, and in this case, the amount added is the amount of the titanate compound as the active ingredient. .

In the water-based adhesive of the present invention, a thickener (viscosity adjuster), an ultraviolet absorber, an antioxidant, a plasticizer, a vulcanizing agent, a vulcanization accelerator, an antifoaming agent are used in accordance with required performance. , A curing agent, a rust preventive, and the like can be arbitrarily added.

When the tackifying resin is added to the water-based adhesive of the present invention, a high initial adhesive strength and a normal adhesive strength can be exhibited. At this time, the type of the tackifier resin is not particularly limited. Specifically, rosin resin, polymerized rosin resin, α-pinene resin, β-pinene resin, terpene phenol resin, C5 fraction petroleum resin, C
9 fraction petroleum resin, C5 / C9 fraction petroleum resin, DCP
D-based petroleum resins, alkylphenol resins, xylene resins, coumarone resins, coumarone-indene resins, and the like.

When the tackifier resin is added, the method of addition is not particularly limited, but it is preferable to add the resin as an emulsion in order to uniformly disperse the resin in the adhesive. Further, the method for producing the tackifying resin includes a method in which a substance dissolved in an organic solvent such as toluene is emulsified or dispersed in water using an emulsifier, and then the organic solvent is removed by heating under reduced pressure. There is a method of emulsifying or dispersing, and the former, which can produce a fine particle emulsion, is preferable.

The amount of the tackifying resin to be added is preferably 20 to 80 parts by weight of solids per 100 parts by weight of solids of polychloroprene latex. If the amount is less than 20 parts by weight, the initial adhesive strength is insufficient. If the amount is more than 80 parts by weight, the formation of the adhesive film is hindered, and both the initial adhesive strength and the normal adhesive strength decrease.

[0026]

EXAMPLES The present invention will be described below with reference to examples, but these examples do not limit the present invention.

The polychloroprene latex was polymerized by the following method. [Preparation of polychloroprene latex] Polymerization was carried out in a nitrogen atmosphere using a disproportionated rosin as an emulsifier and a 2% aqueous solution of potassium persulfate as a catalyst in a 3 liter reactor. Weight average molecular weight of 54
It was prepared using n-dodecyl mercaptan as a chain transfer agent so that the gel content was 15% and the solid content was 60% by weight.

[Preparation of Adhesive] An adhesive composition was blended and prepared according to the formulation shown in Table 1. [Preparation of primer] Polychloroprene rubber (trade name:
A-90, manufactured by Denki Kagaku Kogyo Co., Ltd.) 3 parts by weight, 82 parts by weight of toluene and 15 parts by weight of methyl ethyl ketone were mixed and dissolved to prepare a 3% by weight solution. This solution was used as a primer.

The water-resistant adhesive performance and the properties of the latex were evaluated by the following methods. [Initial adhesive strength evaluation test] SBR (styrene-butadiene copolymer rubber) (size of margin portion is width 20 mm x length 7)
0 mm) The surface of each of the two sheets was uniformly polished by a belt rotating buffing apparatus. Thereafter, the polished surface was washed with toluene, and a primer was applied at 200 g (wet) / m ² ,
It was dried in a 0 ° C. atmosphere for 5 minutes. 20 glue on it
It was applied with a brush of 0 g (wet) / m ² , dried in an atmosphere of 60 ° C. for 5 minutes, laminated, and pressed with a hand roller. Ten minutes after the pressure bonding, the 180 ° peel strength was measured at a tensile speed of 200 mm / min using a tensile tester.

[Normal Adhesion Strength Evaluation Test] SBR (styrene-butadiene copolymer rubber) (size of margin portion is width 20)
(mm × 70 mm in length), each of which was uniformly polished with a belt rotating buffing apparatus. Thereafter, the polished surface was washed with toluene, and the primer was coated with 200 g (wet) / m
^{2 was} applied and dried in an atmosphere of 60 ° C. for 5 minutes. The adhesive was applied thereon with a 200 g (wet) / m ² brush, and
After drying in an atmosphere at a temperature of 5 ° C. for 5 minutes, the sheets were laminated and pressed with a hand roller. Five days after the pressure bonding, the 180 ° peel strength was measured at a tensile speed of 200 mm / min using a tensile tester.

[Evaluation test of heat-resistant adhesive strength at 80 ° C.] Two SBR (styrene-butadiene copolymer rubber) (the size of the adhesive margin is 20 mm in width × 70 mm in length) are uniformly surfaced by a belt rotating buffing device. Polished. Thereafter, the polished surface was washed with toluene, and 200 g of primer (we
t) / m ² and dried in an atmosphere of 60 ° C. for 5 minutes.
The adhesive was applied thereon with a brush of 200 g (wet) / m ² , dried in an atmosphere of 60 ° C. for 5 minutes, laminated, and pressed with a hand roller. One day after crimping, one end of the sample was fixed in an atmosphere of 80 ° C., and 1 k
Apply a load of g. After 30 minutes, the peeled length was measured. Those that fell within 30 minutes were designated as "falls".

[Evaluation test for heat resistance at 100 ° C.] SBR
Two (styrene-butadiene copolymer rubber) (size of the margin portion was 20 mm in width × 70 mm in length) were each uniformly polished with a belt rotating buffing device. afterwards,
The polished surface was washed with toluene, and 200 g (w
et) / m ² and dried in an atmosphere of 60 ° C. for 5 minutes. The adhesive was applied thereon with a brush of 200 g (wet) / m ² , dried in an atmosphere of 60 ° C. for 5 minutes, laminated, and pressed with a hand roller. One day after the crimping, one end of the sample was fixed in an atmosphere of 100 ° C., and 4
Apply a load of 50 g. After 30 minutes, the peeled length was measured. Those that fell within 30 minutes were designated as "falls".

[Solid Content Concentration] Only the aluminum dish was weighed and designated as A. An aluminum dish containing 2 ml of the latex sample was weighed and designated B. 110 ° C aluminum plate with latex sample
After drying in an atmosphere for 2 hours, the sample was weighed and designated C. The solid concentration (%) was determined by the following equation. Solid concentration = {(CA) / (BA)} × 100

[Weight average molecular weight of soluble part]
PC measurements were made. The molecular weight was calculated in terms of polystyrene. The sample is the separated sol, 0.1 wt% THF
Adjusted to solution. Column size: 7.5mmΦ × 50mm (GUAR
D), 7.5 mmΦ × 300 mm (Mixed-B) Column temperature: 35 ° C., solvent: THF, Outflow rate: 1 ml / min Detector: SHIMAZU RID-6A

[Measurement of Toluene-Insoluble Content (Gel Content)] A latex sample was freeze-dried and weighed to obtain A. 2 at 23 ° C
After dissolving with toluene (adjusted to 0.6%) for 0 hour, the gel was separated using a centrifuge and further using a 200 mesh wire mesh. After air-drying the gel content,
After drying for a time, it was weighed to B. The gel content (%) was calculated according to the following equation. Gel content = (B / A) × 100 Table 1 shows the evaluation results of the aqueous adhesives obtained in Examples 1 and 2 and Comparative Examples 1 to 3.

[0036]

[Table 1]

The ingredients in Table 1 are as follows. Note 1) Trade name: Tamanol E-100 (manufactured by Arakawa Chemical Industries, Ltd.), solid content 53%, terpene phenolic resin Note 2) Trade name: Heidilite H-42M (manufactured by Showa Denko KK), aluminum hydroxide powder Note 3) Trade name: KR9SA (manufactured by Ajinomoto Fine Techno Co., Ltd.), 90% active ingredient, added by wet processing using isopropyl tri-n-dodecylbenzenesulfonyl titanate and methyl ethyl ketone as a solvent. Note 4) Trade name: KR44 (Ajinomoto 90% active ingredient, added by wet processing using isopropyl tri (N-aminoethyl) titanate and methyl ethyl ketone as solvents. Note 5) Trade name: A-186 (manufactured by Nippon Unicar Co., Ltd.), effective Component 50%, β (3,4-epoxycyclohexyl) ethyltrimethoxysilane, methano 6) Trade name: A-1100 (manufactured by Nippon Unicar Co., Ltd.), active ingredient 50%, γ-aminopropyltriethoxysilane, mixture of methanol and methyl ethyl ketone Added by wet processing using a solvent as a solvent. Note 7) Trade name: Alon A-20L (manufactured by Toagosei Co., Ltd.), solid content 17%, sodium polyacrylate. Note 8) Trade name: SBU-0772 (Sumitomo Bayer Urethane). Co., Ltd.), 100% solid content, water-dispersible isocyanate compound KR9SA, KR of coupling agents (Notes 3 to 6) in the table
Since 44, A-186 and A-1100 contain an organic solvent such as methanol and toluene in addition to the coupling agent component, the active ingredient of the coupling agent is specified.

[0038]

As is clear from Table 1, the water-based adhesive of the present invention (Examples 1 and 2) uses a water-based adhesive (Comparative Example 1) not using a conventional coupling agent and a silane coupling agent. Unlike the water-based adhesives (Comparative Examples 2 and 3), they exhibited high initial adhesive strength, normal adhesive strength, and heat resistant adhesive strength.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J040 CA151 CA161 HA026 HA036 HA066 HA076 HA136 HA156 HA176 HA196 HA206 HA246 HA256 HA296 HA306 HA316 HA326 HA356 HA366 HB07 JA03 KA16 KA42 LA08 MA10 MA12 NA05 NA15

Claims (4)

[Claims] An aqueous adhesive comprising (A) a polychloroprene latex, (B) an inorganic filler, and (C) a titanate coupling agent. 2. Component (B) is used in an amount of 1 to 80 parts by weight and component (C) is used in an amount of 0.02 parts by weight based on 100 parts by weight of the solid component.
The water-based adhesive according to claim 1, wherein the amount is from 01 to 10 parts by weight. 3. The aqueous adhesive according to claim 1, wherein the component (B) is a hydroxide or a silicate. 4. The aqueous adhesive according to claim 1, wherein the component (B) is aluminum hydroxide.