JP2001089737A - Aqueous adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous adhesive most suitable for adhesion of an expanded rubber material and textiles of a wet suit. SOLUTION: This aqueous adhesive is a two-part type aqueous adhesive combined a principal ingredient containing a polychloroprene latex of which the polymer structure is a copolymer of chloroprene and 2,3-dichloro-1,3- butadiene and a tackifying resin and used a rosin acid alkali metallic salt as an emulsifying agent with a curing agent containing an isocyanate compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive for bonding a foamed rubber material to a cloth, and more particularly to an adhesive suitably used for bonding a foamed rubber material constituting a wet suit to a cloth.

[0002]

2. Description of the Related Art Conventionally, a wet suit is formed by forming a laminated sheet obtained by applying a polychloroprene (CR) solvent-based adhesive to a foamed rubber material and laminating cloths, and then forming and sewing the sheet. It is created by taping joints. However, since organic solvents such as toluene, ethyl acetate, and methyl ethyl ketone are used for CR solvent-based adhesives, the organic solvents volatilize in the workplace during the application of the adhesive, resulting in safety and hygiene for workers and environmental protection. Undesirably, reduction of the organic solvent has been desired.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and has problems in health and safety and environment as in the case of using a conventional CR solvent-based adhesive. In addition, an object of the present invention is to provide an adhesive and an adhesive structure that are firmly bonded to a conventional CR solvent-based adhesive at least as strongly.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted various studies in order to achieve the above object, and as a result, have used chloroprene and 2,3-
The above-mentioned problems have been solved by a two-pack water-based adhesive obtained by combining a polychloroprene latex obtained by emulsion-copolymerizing dichloro-1,3-butadiene, a main agent containing a tackifying resin, and a curing agent containing a water-dispersed isocyanate compound. The present invention has been found to be solved, and the present invention has been completed. The adhesive of the present invention comprises chloroprene polymerized by using an alkali metal rosin acid salt as an emulsifier and 2,3-dichloro-1,3.
A polychloroprene latex mainly containing a copolymer with butadiene (hereinafter sometimes simply referred to as the copolymer of the present invention) and a tackifying resin are mixed in a solid content of 100%;
A main agent contained in a ratio of 20 to 100 parts by weight to 20 parts by weight;
A two-pack type water-based adhesive characterized by being combined with a curing agent containing a water-dispersed isocyanate compound.
In the above two-part water-based adhesive, chloroprene and 2,2
The copolymer with 3-dichloro-1,3-butadiene preferably has a toluene-insoluble content of 50 to 99 parts by weight.

Hereinafter, the contents of the present invention will be described in detail. The polychloroprene latex in the present invention is 2-chloro-1,3-butadiene (hereinafter referred to as chloroprene).
And a latex obtained by emulsion copolymerization of 2,3-dichloro-1,3-butadiene and 2,3-dichloro-1,3-butadiene in the presence of an alkali metal salt of rosin acid.

The amount of 2,3-dichloro-1,3-butadiene to be charged is not particularly limited, but 2,3-dichloro-1,3-butadiene is 2 to 30% by weight of the total 100 parts by weight of the monomers. Part. By copolymerizing 2,3-dichloro-1,3-butadiene in an amount of 2 parts by weight or more, the crystallinity of the polymer can be lowered, and the wet suit can be given flexibility and good comfort.
However, when the amount of 2,3-dichloro-1,3-butadiene is more than 30 parts by weight, the crystallinity is rather increased, and the adhesive layer becomes hard, so that the flexibility of the wet suit is lost. If necessary, 2,3-dichloro-
A monomer copolymerizable with chloroprene other than 1,3-butadiene may be copolymerized. Examples of monomers copolymerizable with chloroprene other than 2,3-dichloro-1,3-butadiene include 1-chloro-1,3-butadiene, butadiene, isoprene, styrene, acrylonitrile, acrylic acid, and acrylic acid esters. , Methacrylic acid and methacrylic acid esters.

The emulsifier used in the emulsion polymerization of the polychloroprene latex in the present invention is an alkali metal salt of rosin acid, and specific examples thereof include sodium rosinate and potassium rosinate.

In the present invention, the addition amount of the alkali metal rosin acid used for the emulsion polymerization of the polychloroprene latex is chloroprene and 2,3-dichloro-1,3-
The amount is preferably 0.1 to 10 parts by weight based on 100 parts by weight of a monomer mixture containing butadiene as an essential monomer. If the amount is less than 0.1 part by weight, the emulsifying power is not sufficient, and if it exceeds 10 parts by weight, the adhesive force of the adhesive may be impaired.

The method for polymerizing the copolymer of the present invention is not particularly limited, and the polymerization temperature, polymerization catalyst, chain transfer agent, polymerization terminator, final polymerization rate, demonomerization, concentration conditions, etc. are appropriately selected. , It is possible to adjust the solid content concentration, the molecular weight of the toluene-soluble portion, the toluene-insoluble content (gel content), and the like.

[0010] The polymerization temperature of the copolymer of the present invention is not particularly limited, but the polymerization temperature is preferably 10 to 50 ° C in order to smoothly carry out the polymerization reaction. 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 chain transfer agent of the copolymer of the present invention is not particularly limited, and those usually used for emulsion polymerization of chloroprene can be used. Examples thereof include n-dodecyl mercaptan and tert-dodecyl mercaptan. Long chain alkyl mercaptans, dialkyl xanthogen disulfides such as diisopropyl xanthogen disulfide and diethyl xanthogen disulfide, and known chain transfer agents such as iodoform can be used.

The polymerization terminator (polymerization inhibitor) of the copolymer of the present invention is not particularly limited, and for example, 2,6-tert-butyl-4-methylphenol, phenothiazine, hydroxyamine and the like can be used.

[0013] The final polymerization rate of the copolymer of the present invention is not particularly limited and can be arbitrarily adjusted, and unreacted monomers are removed by a demonomerization operation.
The method is not particularly limited. The polychloroprene latex of the present invention can be controlled to a required solid concentration by concentrating or diluting by adding water or the like. Examples of the method for concentration include concentration under reduced pressure, but are not particularly limited. In consideration of the drying speed of the adhesive and the storage stability of the adhesive main agent, the solid concentration of the polychloroprene latex is preferably 50 to 70% by weight.

The polychloroprene latex in the present invention has a toluene insoluble content (gel content) of the copolymer of 50.
If it is -99% by weight, an adhesive excellent in balance between initial adhesive strength and normal adhesive strength can be obtained. When the toluene insoluble content is lower than 50% by weight, the normal adhesive strength of the adhesive is insufficient, and it is industrially difficult to obtain a copolymer exceeding 99% by weight.

The tackifying resin in the present invention is not particularly limited. Specifically, rosin resin, polymerized rosin resin, α-pinene resin, β-pinene resin, terpene phenol resin, C ₅ fraction petroleum resin, C ₉ fraction petroleum resin, C ₅ / C ₉ fraction system Petroleum resin, DCPD petroleum resin, alkylphenol resin, xylene resin, cumarone resin,
Coumarone indene resin and the like. In the actual wet suit bonding step, a heating step of 100 ° C. or more can be provided. In this case, the softening point temperature of the selected resin is preferably 80 to 160 ° C.

The method of adding the tackifier resin is not particularly limited, but it is preferable to add the resin as an aqueous emulsion in order to uniformly disperse the resin in the adhesive. Further, a method for producing an aqueous emulsion of a tackifier resin includes a method of dissolving in an organic solvent such as toluene, emulsifying / dispersing in water using an emulsifier, and removing the organic solvent by heating under reduced pressure; And crushed to emulsify /
Although there is a method of dispersing, etc., the former capable of producing a fine particle emulsion is preferable.

The amount of the tackifying resin (solid content)
The polychloroprene latex is preferably 20 to 100 parts by weight based on 100 parts by weight of the solid content. If the amount is less than 20 parts by weight, the adhesive strength to the surface of the foamed rubber material is insufficient, and if it exceeds 100 parts by weight, the adhesive layer becomes brittle and poor adhesion is likely to occur.

The main components of the two-part water-based adhesive of the present invention comprise polychloroprene latex and a tackifying resin as essential components, but according to the required performance, a metal oxide, a thickener, a filler, and an ultraviolet absorber , An antioxidant, a film forming aid, a plasticizer, a vulcanizing agent, a vulcanization accelerator, an antifoaming agent and the like can be optionally added. In order to extend the storage stability of the main ingredient,
What is necessary is just to add a metal oxide, specifically, zinc oxide,
Magnesium oxide and the like. The metal oxide can suppress a decrease in pH due to a dehydrochlorination reaction of the polychloroprene polymer. When adjusting the viscosity of the main ingredient,
A thickener may be added. Specific examples of the thickener include sodium polyacrylate, associative polyurethane emulsion, and alkali-swellable acrylic emulsion. In order to reduce product cost, it is effective to add a filler to the base material, and specific fillers include calcium carbonate, titanium oxide, and synthetic silica.

The water-dispersible isocyanate compound which is a curing agent component of the present invention has a structure such as buret, isocyanurate, urethane, uretdione, allophanate, etc. in a molecule obtained from an aliphatic and / or alicyclic diisocyanate. It is obtained by introducing a hydrophilic group into a polyisocyanate polymer. That is, it is a self-emulsifying isocyanate compound that can be dispersed as fine particles in water when added and stirred in water. Examples of the aliphatic and / or alicyclic isocyanate include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate, lysine diisocyanate (LDI), isophorone diisocyanate (IPDI), and hydrogenated xylylene diisocyanate. Isocyanate (hydrogenated XDI), tolylene diisocyanate (TDI), 4,
4'-diphenylmethane diisocyanate (MDI),
Polymerized MDI, xylylene diisocyanate (XDI),
Naphthylene diisocyanate (NDI), paraphenylene diisocyanate (PPDI), tetramethylxylylene diisocyanate (TMXDI), dicyclohexylmethane diisocyanate (HMDI), isopropylidene bis (4-cyclohexyl isocyanate) (IP
C), cyclohexyl diisocyanate (CHPI),
Trizine diisocyanate (TODI) and the like. Among them, HDI, MDI, IPDI, hydrogenated XDI
Is easily available industrially and is good. The effect as a curing agent in the present invention is based on JIS rather than a raw material compound.
It depends on the isocyanate group content calculated by the method specified in K-7301. In order to obtain good adhesive strength, the water-dispersed isocyanate compound used preferably has an isocyanate group content of 17 to 25% by weight.

The curing agent for the two-part water-based adhesive of the present invention comprises a water-dispersible isocyanate compound as an essential component, but may be any other water or organic solvent capable of dissolving the water-dispersible isocyanate compound. Etc. can be included. However, isocyanate groups also react with water,
If it is not necessary to adjust the viscosity of the curing agent, it is preferable to use a water-dispersed isocyanate compound alone as the curing agent.

The mixing ratio of the main agent and the curing agent is such that the polychloroprene latex in the main agent is 100 parts by weight in solid content and the water-dispersible isocyanate compound in the curing agent is 0.5 to 15 parts by weight in solid content. It is preferable to mix them. If the amount is less than 0.5 parts by weight, the adhesive strength is insufficient, and
If more than 5 parts by weight is added, the hardness of the adhesive layer is increased, and the elasticity when tailoring into a wet suit may be hindered. The viscosity of the adhesive may be adjusted according to the specifications of the coating method and the coating apparatus, but the viscosity after mixing the main agent and the curing agent is 1000 to 12000 [mP · s].
(B-type viscometer, 25 ° C., 30 rpm). If the viscosity is less than 1000 [mPa · s], repelling on the surface of the foamed rubber material may become a problem,
If it is higher than 00 [mP · s], uniform application becomes difficult.

The adhesive of the present invention is used for bonding a foamed rubber material to a cloth, and is particularly suitably used for bonding a foamed rubber material, which is a constituent material of a wet suit, to a cloth. The foamed rubber material is a natural or synthetic foamed rubber material generally used for wet suits, and has elasticity. Specifically, it has closed cells such as polychloroprene or chlorosulfonated polyethylene. In particular, when foamed polychloroprene is the adherend, the most excellent adhesive strength can be exhibited. The cloth as the other adherend is a woven fabric, a knitted fabric or a non-woven fabric, but is preferably a stretchable woven fabric or a knitted fabric, and is a woven or knitted fabric of a two-way tricot (having a stretch property in both length and width). More preferably, there is. Specific examples include a nylon jersey and a polyester jersey. Particularly, it can exhibit good adhesive strength to a nylon jersey most commonly used in a wet suit.

The method of using the adhesive of the present invention is not particularly limited. However, after mixing the main agent and the curing agent, the mixture is applied to the surface of the foamed rubber material, and immediately, that is, before the adhesive is dried, the cloths are stacked. The most suitable is the method of bonding. The state before the adhesive is dried means that the moisture in the adhesive layer is reduced by 80%, that is, when the moisture in the adhesive at the time of mixing the main agent and the curing agent is 100%, It means the time until it reaches 20%, during which the cloths are stacked. Further, it is preferable to press after heating or at the same time as heating at 60 to 150 ° C. after laminating the cloths, so that a high adhesive strength can be obtained immediately after lamination. The reason why the method of immediately applying and bonding the cloths is suitable is that the adhesive is applied to the cloths by applying the cloths when the adhesive is in a wet state. Occasionally, better adhesion can be obtained than with the method of stacking cloths. The method and apparatus for applying the adhesive are not particularly limited. Specific examples include a curtain flow coater method, a bar coater method, a roll coater method, and the like.
Further, examples of the roll coater method include a gravure roll coater method and a reverse gravure roll coater method. Among these, a roll coater method that can apply the adhesive more uniformly is preferable. The application amount of the adhesive is not particularly limited, but it is necessary to control the adhesive so that the adhesive does not exude from the cloth, and preferably ^{20 to} 200 g / m ² (wet).

[0024]

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

EXPERIMENTAL EXAMPLE 1 In a nitrogen atmosphere, 85 parts by weight of water, 5 parts by weight of sodium salt of rosin acid having an acid value of 160, and 0.1 part of potassium hydroxide were prepared in a 3 liter reactor in a nitrogen atmosphere.
8 parts by weight, 0.3 part by weight of a sodium salt of formaldehyde naphthalene sulfonic acid condensate, 0.3 part by weight of sodium bisulfite were charged, and after dissolution, 92 parts by weight of a chloroprene monomer and 2,3-dichloro- 8 parts by weight of 1,3-butadiene, 0.03 of n-dodecyl mercaptan
Parts by weight were added. Using 0.1 part by weight of potassium persulfate as an initiator, polymerization was carried out at 40 ° C. under a nitrogen atmosphere, and when the final polymerization rate reached 90%, an emulsion of phenothiazine was added to terminate the polymerization. Remove unreacted monomers under reduced pressure,
A polychloroprene latex was obtained. Next, this latex was concentrated by heating under reduced pressure to prepare a solid content of 60% by weight. The solid content of this polychloroprene latex and the gel content of the polymer were measured by the following methods. The solid content was 60% by weight and the gel content was 92% by weight.

[Solid Content Concentration]
And An aluminum dish containing 2 ml of the latex sample was weighed and designated B. Place the aluminum dish containing the latex sample in 110
After drying in an atmosphere at a temperature of 2 ° C. for 2 hours, it was weighed to obtain C. The solid concentration (%) was determined by the following equation. Solid content concentration = {(CA) / (BA)} × 100 [Measurement of toluene-insoluble matter (gel content)] A latex sample was freeze-dried and weighed to obtain A. After dissolving with toluene (adjusted to 0.6% by weight) at 23 ° C. for 20 hours, the gel was separated using a centrifuge and further using a 200-mesh wire mesh. The gel was air-dried and then dried for 1 hour in a 110 ° C. atmosphere. The gel content (% by weight) was calculated according to the following equation. Gel content = (B / A) × 100

Example 1 A terpene phenol resin-based tackifying resin having a softening point of 150 ° C. (Tamanol E-based) was used based on 100 parts by weight of the solid content of the latex obtained in Experimental Example 1.
100 / Arakawa Chemical Industries, Ltd.) 45 parts by weight (solid content conversion), sodium polyacrylate thickener (Aron A-20L / Toagosei Co., Ltd.) 2 parts by weight (solid content conversion), oxidation 3 parts by weight of zinc (2 types of zinc white / manufactured by Sakai Chemical Industry Co., Ltd.) was blended and used as a main ingredient. As the curing agent, a water-dispersible isocyanate compound having an isocyanate group content of 18.6% by weight (Takenate WD-730 / Takeda Pharmaceutical Co., Ltd.) alone is used. The dispersion type isocyanate compound was used by mixing with the main ingredient so that the content of the dispersion type is 3 parts by weight. This two-part water-based adhesive is referred to as an adhesive A.

After applying an adhesive obtained by mixing a main agent and a curing agent to foamed polychloroprene (thickness: 3 mm) at 80 g / m ² , immediately overlay a nylon jersey cloth and press-bond for 1 minute by a press machine heated to 110 ° C. did. This bonding method is referred to as bonding method A.

With respect to the test piece obtained by the bonding method A (the size of the margin portion is 2 cm wide × 7 cm long), the following adhesive strength evaluation test was performed. [Initial Adhesive Strength Evaluation Test] Ten minutes after pressure bonding, a 180 ° peel strength was measured with a tensile tester at a tensile speed of 200 mm / min. [Normal adhesive strength evaluation test] Seven days after pressure bonding, a 180 ° peel strength was measured at a tensile speed of 200 mm / min using a tensile tester. [Water resistance adhesive strength evaluation test] One day after pressing, 7
After soaking for days, pulling speed 200mm / mi with tensile tester
The 180 ° peel strength was measured at n.

Example 2 The polychloroprene latex of Example 1 was used with a softening point of 1 based on 100 parts by weight of solids.
40 parts by weight (in terms of solid content) of a polymerized rosin-modified pentaester-based tackifying resin (Hariester SK-130D / Harima Kasei Co., Ltd.) at 30 ° C, a sodium polyacrylate-based thickener (Alon A-20L / Toa) 2 parts by weight (manufactured by Gosei Co., Ltd.) (in terms of solid content) and 3 parts by weight of zinc oxide (2 types of zinc white / manufactured by Sakai Chemical Industry Co., Ltd.) were used as the main ingredients. The curing agent is a water-dispersed isocyanate compound having an isocyanate group content of 18.6% by weight (takenate WD-
730 / Takeda Pharmaceutical) was used alone and mixed with the main component so that the polydisperse isocyanate compound was 3 parts by weight per 100 parts by weight of the solid polychloroprene latex. This two-component aqueous adhesive is referred to as adhesive B. Using adhesive B mixed with main agent and curing agent,
A test piece was prepared by bonding the foamed polychloroprene to the nylon jersey cloth by the same method as the bonding method A of Example 1, and the same adhesive strength evaluation test as in Example 1 was performed.

Example 3 The polychloroprene latex of Example 1 was used with a softening point of 8 based on 100 parts by weight of solid content.
45 ° C. (solid content) of an α-methylstyrene polymer-based tackifier resin (Tacoline 5001 / Rika Hercules Co., Ltd.) at 5 ° C., a sodium polyacrylate thickener (Alon A-20L / Toagosei Co., Ltd.) 2 parts by weight (solid content) and 3 parts by weight of zinc oxide (two types of zinc white / manufactured by Sakai Chemical Industry Co., Ltd.) were used as the main ingredients. As the curing agent, a water-dispersible isocyanate compound having an isocyanate group content of 18.6% by weight (Takenate WD-730 / Takeda Pharmaceutical Co., Ltd.) alone is used. The dispersion type isocyanate compound was used by mixing with the main ingredient so that the content of the dispersion type is 3 parts by weight. This two-part water-based adhesive is referred to as an adhesive C.
Using a bonding agent C obtained by mixing a main agent and a curing agent, a foamed polychloroprene and a nylon jersey cloth were bonded by the same method as in the bonding method A of Example 1, a test piece was prepared, and the same bonding as in Example 1 was performed. A force evaluation test was performed.

Comparative Example 1 Denkachloroprene A-90
(Polychloroprene rubber, manufactured by Denki Kagaku Kogyo Co., Ltd.) 1
With a composition ratio of 00 parts by weight, 460 parts by weight of toluene, 115 parts by weight of methyl ethyl ketone, 90 parts by weight of methyl methacrylate, and 0.5 part by weight of benzoyl peroxide, a graft reaction of methyl methacrylate was performed to prepare a CR solvent-based adhesive. . 2,6-t-butyl-4-methylphenol was used as a polymerization terminator, and the conversion of methyl methacrylate was controlled to about 30%. This solvent-based adhesive is referred to as an adhesive D. Bonding method A of Example 1 using adhesive D
In the same manner as in Example 1, the foamed polychloroprene and the nylon jersey cloth were bonded to prepare a test piece, and the same adhesive strength evaluation test as in Example 1 was performed.

Table 1 shows the evaluation results of the latex compositions obtained in Examples 1 to 3 and Comparative Example 1.

[0034]

[Table 1]

[0035]

As is evident from Table 1, the two-part water-based adhesive of the present invention (Examples 1 to 3) has an adhesive strength higher than or equal to that of the conventional CR solvent-based adhesive (Comparative Example 1). Show.

Claims (3)

[Claims] 1. A polychloroprene latex mainly containing a copolymer of chloroprene and 2,3-dichloro-1,3-butadiene obtained by polymerization using an alkali metal rosinate as an emulsifier, and a tackifying resin. A two-component water-based adhesive, which comprises a combination of a main agent containing 100 parts by weight to 20 to 100 parts by weight in terms of solid content and a curing agent containing a water-dispersed isocyanate compound. 2. Chloroprene and 2,3-dichloro-1,2
The toluene insoluble content of the copolymer with 3-butadiene is 50 to
2. The two-part water-based adhesive according to claim 1, wherein the amount is 99% by weight. 3. A wet suit comprising a foamed rubber material and a cloth bonded to each other using the adhesive according to claim 1.