JP2001089727A - Foamed rubber material, bonding of wet suit and bonded structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for bonding a foamed rubber material such as wet suit to a cloth without using an adhesive containing an organic solvent (solvent-type adhesive) and provide a bonded structure. SOLUTION: The process for bonding a foamed rubber 1 to a cloth 3 comprises a step to apply an adhesive 2 to the surface of a foamed rubber 1 and a step to bond the rubber to a cloth by placing the cloth 3 on the adhesive 2 before the drying of the adhesive. The adhesive is a two-pack water-base adhesive comprising a combination of a main agent containing a tackifier resin and a polychloroprene latex obtained by the emulsion copolymerization of chloroprene and 2,3-dichloro-1,3-butadiene using an alkali metal rosinate as an emulsifier 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 a bonding method and a bonding structure for bonding a foamed rubber material to a cloth, and more particularly to a bonding method for suitably bonding a foamed rubber material and a cloth constituting a wet suit. And an adhesive structure.

[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 a cloth, and then molding or sewing the laminated sheet. It is created by taping the seams. 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. It is another object of the present invention to provide a method and an adhesive structure for firmly bonding at least equivalently to those using a conventional CR solvent-based adhesive.

[0004]

Means for Solving the Problems As a result of repeated studies to achieve the above object, the present inventors have used an alkali metal salt of rosin acid as an emulsifier, and prepared chloroprene and 2,3-dichloro-1,3-dichloromethane. A polychloroprene latex mainly containing a copolymer obtained by emulsion copolymerization of butadiene (hereinafter sometimes simply referred to as the copolymer of the present invention), a main agent containing a tackifying resin, and a water-dispersed isocyanate compound Using a two-part water-based adhesive in which a hardening agent is combined, a cloth 3 shown in FIG.
In the bonding method of bonding the adhesive, the step of applying the adhesive 2 of FIG. 1B to the surface of the foamed rubber material 1 of FIG. 1A, and immediately after applying the adhesive, that is, the adhesive is dried. Previously, it was found that the above-mentioned problems could be solved by a bonding method including a step of laminating and bonding the cloths of FIG. 1C on the adhesive 2, and completed the present invention. . That is, the present invention relates to a method for bonding a foamed rubber material and cloth, wherein chloroprene and 2,3-dichloro-form are added to the surface of the foamed rubber material by using an alkali metal rosinate as an emulsifier.
Polychloroprene latex obtained by emulsifying and copolymerizing 1,3-butadiene and a tackifying resin were converted to a solid content of 100%.
A main agent contained in a ratio of 20 to 100 parts by weight to 20 parts by weight;
The method includes a step of applying a two-part water-based adhesive in which a curing agent containing a water-dispersed isocyanate compound is combined, and a step of superimposing a cloth on the adhesive and pressing the adhesive immediately after the application of the adhesive. This is a bonding method characterized by the following. In this case, the polymer of polychloroprene latex contained in the adhesive base material has a toluene-insoluble content of 50 to 99% by weight.
It is preferable that Further, the present invention is an adhesive structure in which cloths are adhered to a surface of an adhesive layer applied to a foamed rubber material obtained by the above-mentioned bonding method.

Hereinafter, the contents of the present invention will be described in detail. As the foamed rubber material in the present invention, a natural or synthetic foamed rubber material is suitably used without particular limitation, and specifically, has closed cells such as polychloroprene or chlorosulfonated polyethylene, In addition, any elastic rubber material can be suitably used. However, when tailoring to a wet suit,
Considering the fit to the body, elasticity, light weight, heat insulation and heat retention effects, foamed polychloroprene is preferred. Further, for example, Japanese Patent Application Laid-Open No. H11-79078 (applicant:
It may be formed by laminating foamed rubber materials having different hardness or expansion ratio as proposed and used by Inapoli Trading Co., Ltd.).

The cloth in the present invention is a woven fabric, a knitted fabric or a nonwoven fabric, but is preferably a stretchable woven fabric or a knitted fabric, and is a two-way tricot (having a stretch property in both length and width). Is more preferred.
Specifically, a nylon jersey, a polyester jersey, or the like can be given. Particularly for wet suit applications, nylon jersey is most preferable in consideration of stretchability and breathability.

[0007] The polychloroprene latex in the present invention refers to 2-chloro-1,3-butadiene (hereinafter referred to as chloroprene) and 2,3-dichloro-1,3-butadiene in the presence of an alkali metal salt of rosin acid. It is a latex obtained by emulsion copolymerization.

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 based on the total of 100 parts by weight of the monomer. 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.

The amount of the alkali metal rosinate used in the emulsion polymerization of the polychloroprene latex in the present invention 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.

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.

[0015] The final polymerization rate of the copolymer of the present invention is not particularly limited and can be arbitrarily adjusted. 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 polymer exceeding 99% by weight.

The tackifier 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 for adding the tackifier resin is not particularly limited, but it is preferable to add the tackifier 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 in the present invention include polychloroprene latex and a tackifying resin as essential components. According to the required performance, metal oxides, thickeners, fillers, ultraviolet absorbers , 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 contains a water-dispersible isocyanate compound as an essential component, but other than this, water or an organic solvent capable of dissolving the water-dispersible isocyanate compound can be used. 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 component and the curing agent is such that the polychloroprene latex in the main component 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) is preferred. If the viscosity is less than 1000 [mPa · s], repelling on the surface of the foamed rubber material may become a problem, and the viscosity is 12,000.
If it is higher than [mP · s], uniform application becomes difficult.

In the step of applying the adhesive to the foamed rubber material in the bonding method of the present invention, the method of applying the adhesive and the specifications of the apparatus are not particularly limited. Specific examples include a curtain flow coater method, a bar coater method, a roll coater method, and the like. Further, the roll coater method includes a gravure roll coater method, a reverse gravure roll coater method, and the like.
Among these, a roll coater method that can apply the adhesive more uniformly is preferable. The amount of application is not particularly limited, but it is necessary to control the adhesive so as not to exude from the cloth, and preferably ^{20 to} 200 g / m ² (wet).

In the bonding step of the present invention, in the step of laminating the cloth on the foamed rubber material and pressing the cloth, the cloth must be laminated immediately after the application of the adhesive, that is, before the adhesive is dried. 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. 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 crimping apparatus, the crimping conditions and the pressing pressure are not particularly limited, and the crimping operation after the cloths are stacked may be either a hot press or a room temperature press. However, in order to obtain a sufficient initial adhesive force, it is preferable to perform drying at 60 to 150 ° C. for 10 seconds to 10 minutes after stacking the cloths simultaneously with or after the pressing operation.

[0026]

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 nitrogen atmosphere using a reactor having an internal volume of 3 liters.
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 (% by weight) 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 phenolic resin-based tackifying resin (Tamanol E-100 / Arakawa Chemical Industries, Ltd.) was added in an amount of 45 parts by weight based on 100 parts by weight of the latex obtained in Experimental Example 1 in terms of solid content. Parts (in terms of solids), 2 parts by weight (in terms of solids) of sodium polyacrylate-based thickener (Aron A-20L / manufactured by Toagosei Co., Ltd.), zinc oxide (zinc white 2 types / Sakai Chemical Industry Co., Ltd.) (3 parts by weight) was 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.

The following adhesive strength evaluation test was performed on the test piece obtained by the bonding method A (the size of the margin portion was 2 cm in width × 7 cm in length). [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.

[Comparative Example 1] An adhesive A obtained by mixing the main agent and the curing agent of Example 1 was mixed with foamed polychloroprene (thickness: 3 m).
m) was applied at 80 g / m ² , and then 10
After drying for minutes, a nylon jersey cloth was overlaid and pressed for 1 minute with a press at room temperature. This bonding method is referred to as bonding method B. The same adhesive strength evaluation test as in Example 1 was performed on the test piece (size of the margin portion 2 cm wide × 7 cm long) obtained by the bonding method B.

[Comparative Example 2] Adhesive A obtained by mixing the main agent and the curing agent of Example 1 was mixed with foamed polychloroprene (thickness: 3 m).
m) was applied at 80 g / m ² , and then 10
After drying for 1 minute, a nylon jersey cloth is put on the
Crimping was carried out for 1 minute by a press machine heated to a temperature of ° C. This bonding method is referred to as bonding method C. For the test piece obtained by the bonding method C (the size of the margin portion is 2 cm wide × 7 cm long), the same adhesive strength evaluation test as in Example 1 was performed.

Comparative Example 3 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% by weight. This solvent-based adhesive is referred to as an adhesive B. A test piece was prepared from the adhesive B by the same bonding method A as in Example 1, and the same adhesive strength evaluation test as in Example 1 was performed.

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

[0036]

[Table 1]

[0037]

As is clear from Table 1, the bonding method of the present invention (Example 1) has a higher adhesive strength than the other bonding methods (Comparative Examples 1 and 2), and the conventional CR solvent-based adhesive ( Comparative Example 3)
Shows high adhesive strength equal to or higher than.

[Brief description of the drawings]

FIG. 1 shows a bonding method and a bonding structure.

[Explanation of symbols]

 1: foam rubber material 2: adhesive 3: cloth

Claims (4)

[Claims] 1. A method for adhering a foamed rubber material and cloth, wherein chloroprene and 2,3-dichloro-form are coated on the surface of the foamed rubber material by using an alkali metal rosinate as an emulsifier.
Polychloroprene latex obtained by emulsifying and copolymerizing 1,3-butadiene and a tackifying resin were converted to a solid content of 100%.
A main agent contained in a ratio of 20 to 100 parts by weight to 20 parts by weight;
The method includes a step of applying a two-part water-based adhesive in which a curing agent containing a water-dispersed isocyanate compound is combined, and a step of pressing a cloth over the adhesive immediately after application of the adhesive. Characteristic bonding method. 2. The polymer of polychloroprene latex contained in the adhesive base material according to claim 1 having a toluene insoluble content of 50.
2. The bonding method according to claim 1, wherein the amount is from about 99% by weight to about 99% by weight. 3. An adhesive structure, wherein a cloth is adhered to a surface of an adhesive layer applied to a foamed rubber material, which is adhered by the adhesion method according to claim 1. 4. A wet suit which is bonded by the bonding method according to claim 1 or 2.