JP3008373B2 - Bonding method between fiber and rubber compound - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method of bonding a fiber and a rubber compound, and more particularly, to a method of bonding a fiber and a rubber compound while maintaining the strength of the fiber. And a method of bonding a fiber and a rubber compound to achieve the following.

2. Description of the Related Art In general, industrial rubber products such as tires, rubber hoses, power transmission belts, and conveyor belts are adhesive composites formed by bonding a fiber material to rubber and reinforced. Conventionally, in order to bond the fiber and the rubber compound as described above, usually, a resorcinol-formalin-rubber latex mixture (hereinafter, RFL) is used.
Called liquid. ) Is known.
However, according to this method, the adhesion obtained between the fiber and the rubber compound is often insufficient.

Therefore, conventionally, in order to solve this problem, fiber
Prior to RFL treatment, a method of treating with an epoxy resin has been proposed. The pretreatment with an epoxy resin gives an adhesive composite having excellent adhesiveness, but is inferior in impact resistance. Therefore, for example, JP-A-58-5243 discloses that after treating a fiber with a solution containing an epoxy compound and a liquid rubber, RF
A method of treating with L solution is described. In addition,
Japanese Patent Application Laid-Open No. 8-124632 proposes a method in which fibers are treated with a urethane-modified epoxy resin and then treated with an RFL solution.

According to these methods, an adhesive composite having excellent adhesive strength and flexibility can be obtained, but the strength of the fiber tends to decrease. Such a decrease in fiber strength is a practically important problem because it reduces the durability of the adhesive composite.

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the conventional bonding of a fiber and a rubber compound, and it is intended that the fiber and the rubber compound be mixed while maintaining the strength of the fiber. It is an object of the present invention to provide a method of bonding a fiber and a rubber compound, which can achieve a strong bond with a product.

Means for Solving the Problems A method for bonding a fiber and a rubber compound according to the present invention is a method for bonding a fiber with a treatment solution containing an epoxy resin, a blocked urethane prepolymer, and a polyamine having one or more amino groups in a molecule. And then resorcinol / formalin /
After the treatment with the rubber latex, the fibers are vulcanized and bonded to the unvulcanized rubber compound.

The epoxy resin is a compound having at least one epoxy group in a molecule, for example, a polyhydric alcohol such as ethylene glycol, glycerin, sorbitol, and pentaerythritol, and a polyalkylene glycol such as polyethylene glycol and epichlorohydrin. Reaction products with halogen-containing epoxy compounds, polyphenols such as resorcin, bis (4-hydroxyphenyl) dimethylethane, phenol-formamide resin, resorcin-formamide resin, and halogen-containing epoxy such as phenol resin and epichlorohydrin The reaction product with the compound is preferably used. An epoxy compound obtained by oxidizing a double bond of an aliphatic or alicyclic unsaturated compound with acetic acid or the like is also preferably used.
Various silane coupling agents having an epoxy group are also preferably used.

The above-mentioned blocked urethane prepolymer is obtained by blocking the terminal isocyanate group of the urethane prepolymer, and is already known and a commercially available product can be used. Blocked urethane prepolymers are, for example, as well known, polyisocyanates such as tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl diisocyanate and various polyols. To give a urethane prepolymer, and the terminal isocyanate group is reacted with a compound having two or more active hydrogens in the molecule, such as trimethylolpropane or pentaerythritol. Further, the blocked urethane prepolymer can also be obtained by reacting a urethane prepolymer with a ketoxime, a phenol, an amine or the like.

In the method of the present invention, the treatment solution contains 80 to 30% by weight of an epoxy resin and 20 to 70% by weight of a blocked urethane prepolymer, based on the total amount. Further, the treatment solution contains the epoxy resin and the blocked urethane prepolymer in a total amount of 1 to 20% by weight in solid content.

Furthermore, in the method according to the invention, the treatment solution contains a polyamine. This polyamine is a monomer compound having one or more amino groups in the molecule, and is used as a curing agent for urethane prepolymers and epoxy resins in the present invention. Normally, when an epoxy resin is reacted with a polyurethane and a polyamine, the reaction between the polyurethane and the polyamine is overwhelmingly fast, so that the resulting polymer has higher flexibility but lower adhesive strength. Therefore,
According to the present invention, by using the blocked urethane prepolymer, the reaction rate between the epoxy resin and the polyamine and the reaction rate between the blocked urethane prepolymer and the polyamine are substantially the same, and the flexibility is reduced without lowering the adhesive strength. Get.

In the present invention, as such a polyamine, for example, diethylenetriamine, 3,3'-dichloro-4,4 '
-Diaminodiphenylmethane, triethylenetetramine, tetraethylenepentamine, 3,3'-dimethyl-4,
Examples thereof include 4'-diaminodicyclohexylmethane, polyamide polyamine, mensendiamine, isophoronediamine, metaxylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and dicyandiamide.

In the present invention, such a polyamine is not particularly limited, but is usually contained such that the active hydrogen equivalent of (epoxy group + isocyanate group) / amine is in the range of 0.5 to 1.5.

As a solvent for forming such a processing solution,
In particular, although not particularly limited, aromatic hydrocarbons such as benzene, xylene, and toluene, aliphatic ketones such as methyl ethyl ketone and methyl isobutyl ketone, and esters such as ethyl acetate and amyl acetate are preferably used.

The treatment of the fiber with such a treatment solution is usually performed by immersing the fiber in the treatment solution and then performing a heat treatment. This heat treatment may be performed at a temperature sufficient to cause the treatment solution attached to the fibers to react and fix.
What is necessary is just to process at ~ 250 degreeC for several minutes.

Then, according to the method of the present invention, the fibers are treated with an RFL solution. As described above, the RFL solution is an aqueous mixture of resorcinol-formalin and rubber latex, and is generally known in the past for bonding rubber and fiber. It is an aqueous mixture obtained by mixing an initial condensate obtained by condensing at a molar ratio of 1/3 to 3/1 in the presence of a basic catalyst with a rubber latex. When the resorcinol / formalin molar ratio is outside the above range, an initial condensate having a molecular weight necessary for adhesion cannot be obtained.

As the rubber latex, generally, a synthetic rubber latex is used. For example, chloroprene rubber latex, styrene-butadiene-vinylpyridine rubber latex, acrylonitrile-butadiene rubber latex,
Hydrogenated nitrile rubber latex is preferably used.

The treatment of the fiber with the RFL solution may be performed at a temperature sufficient to cause the RFL solution attached to the fiber to react and fix the fiber, and may be generally treated at 100 to 270 ° C. for several minutes.

The fiber treated as described above is adhered to the rubber compound,
By vulcanizing and bonding under the usual processing conditions known for the rubber compound, strong adhesion between the fiber and the rubber compound can be achieved while maintaining the strength of the fiber. .

In the present invention, as the rubber, for example, natural rubber, butadiene rubber, isoprene rubber, styrene-butadiene rubber, ethylene-propylene rubber, butyl rubber,
Chloroprene rubber, acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, urethane rubber, silicone rubber, fluorine rubber and the like are used. Such rubbers may, depending on each case, contain appropriate amounts of various reinforcing fillers, antioxidants, plasticizers, vulcanization aids, processing aids, etc. known as ordinary rubber compounds. .

The fibers typically include silk, human silk, polyvinyl alcohol fibers, aliphatic and aromatic polyamide fibers, polyester fibers, carbon fibers, glass fibers, and the like, but are not limited thereto. is not.

EXAMPLES Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1 As shown in Table 1, treatment solutions having various composition were prepared, and polyester fiber cords (1000D / 2 × 5) were prepared.
Was immersed and then heat-treated at 235 ° C. for 1 minute.

17 parts by weight of resorcinol, 15 parts by weight of formalin, 10% by weight
A resorcinol-formalin resin solution is prepared using 13 parts by weight of an aqueous sodium hydroxide solution and deionized water, and 30 parts by weight of the resorcinol-formalin resin solution is mixed with 32 parts by weight of chloroprene rubber latex and 38 parts by weight of deionized water. hand,
An RFL solution was prepared.

The fiber cord was immersed in this RFL solution and heat-treated at 200 ° C. for 1 minute.

Then, 100 parts by weight of chloroprene rubber, 4 parts by weight of magnesium oxide, 15 parts by weight of zinc oxide, 2 parts by weight of a vulcanization accelerator, 0.5 parts by weight of sulfur, 2 parts by weight of an antioxidant, 65 parts by weight of carbon black and 8 parts by weight of oil The above fiber cords were arranged in parallel on an unvulcanized sheet of a rubber compound having the following composition, and vulcanized at 170 ° C. for 30 minutes to obtain an adhesive composite.

A 1-inch wide sample was cut from the adhesive composite, and the 180 ° peel adhesion between the fiber cord and the rubber was measured at a peel speed of 100 mm / min. The results are shown in FIG.

Example 2 In Example 1, the fiber cord was an aromatic polyamide fiber cord (made of Kevlar fiber manufactured by DuPont).
00D / 2 × 3 fiber cord) Except for using, an adhesive composite was obtained in the same manner as in Example 1, and the 180 ° peel adhesion was measured. The results are shown in FIG.

As described above, according to the method of the present invention, the fiber is treated with a treatment solution containing a blocked urethane prepolymer together with an epoxy resin and a polyamine, and then treated with resorcinol.
An adhesive composite in which the fiber and the rubber compound are firmly bonded while maintaining the strength of the fiber by vulcanizing and bonding the fiber to the unvulcanized rubber compound after treatment with formalin rubber latex. Can be obtained.

When a normal urethane prepolymer is used in place of the blocked urethane prepolymer, the reaction between the urethane prepolymer and the polyamine occurs in preference to the reaction between the epoxy resin and the polyamine. Unavoidable, the strength of fiber.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the weight ratio of the blocked urethane prepolymer and the epoxy resin in the treatment solution and the adhesive strength of the polyester fiber cord in the resulting adhesive composite. FIG. 5 is a graph showing a relationship between a weight ratio of a urethane prepolymer and an epoxy resin and an adhesive strength of an aromatic polyamide fiber cord in an obtained adhesive composite.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C08J 5/12 CFC C08J 5/12 CFC CFF CFF // C08L 21:00

Claims (2)

(57) [Claims] (1) treating fibers with a treatment solution containing an epoxy resin, a blocked urethane prepolymer, and a polyamine having at least one amino group in a molecule, and then treating the fibers with resorcinol-formalin rubber latex; A method of bonding a fiber to a rubber compound, comprising bonding the fiber to an unvulcanized rubber compound by vulcanization. 2. A treatment solution comprising 80-30% by weight of epoxy resin and 20% by weight of blocked urethane prepolymer, based on the total amount of epoxy resin and blocked urethane prepolymer.
The method for bonding a fiber and a rubber compound according to claim 1, characterized in that it is contained in an amount of 70 to 70% by weight.