JPH0699869B2 - Method for producing rubber-reinforced polyester fiber - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a polyester fiber for rubber reinforcement. More specifically, it relates to a method for producing a polyester fiber for rubber reinforcement having improved cord strength.

(Prior Art) Polyester fiber is widely used as a fiber for reinforcing rubber in automobile tires, belts, hoses, etc., and is widely used. However, depending on the conditions of use, the strength of the fiber is remarkable. However, the processing method is constrained because it decreases significantly. That is, when treating a polyester tire cord with an adhesive, for the purpose of enhancing the adhesive force and enhancing the characteristics of the fiber such as reduction of the shrinkage rate of the fiber, 20
Although it is processed at a temperature higher than 0 ° C, the strength of the fiber is reduced in this step. In order to improve this, the polyester fiber itself has been improved by reducing the amount of terminal carboxyl groups contained in the polyester fiber,
The characteristics of the chemical agent in the adhesive treatment step and the treatment temperature are more influential.

Conventionally, in order to bond rubber and reinforcing fibers such as polyamide and polyester, the fibers have been immersed in an aqueous dispersion containing a resorcinol-holmaldehyde resin and latex as main components and used. As the latex, a butadiene-vinylpyridine-styrene copolymer latex or a mixed latex of the latex and a styrene-butadiene copolymer latex or a natural rubber latex is generally used.

However, when the polyester fiber is treated with these adhesives, the strength of the fiber is reduced as compared with that when the adhesive is not treated, and therefore improvement is required.

(Problems to be Solved by the Invention) An object of the present invention is a polyester fiber used for reinforcement in rubber products such as tires, belts, hoses, etc. An object of the present invention is to provide an improved method for producing polyester fiber.

(Means for Solving Problems) Thus, according to the present invention, the content of the residual vinyl pyridine monomer in the polymer latex is 0.2% by weight or less of the total solid content in the polymer latex. Provided is a method for producing a polyester fiber for rubber reinforcement having improved cord strength, which comprises treating with a polymer latex.

The vinyl pyridine type polymer latex used in the present invention is a polymer latex which has been conventionally used for adhering fibers and rubber, and usually contains 45 to 95% by weight of a conjugated diene monomer and an aromatic vinyl compound. .About.30% by weight and vinylpyridine 5 to 40% by weight.

Among the monomers used for producing the copolymer latex used in the present invention, examples of the conjugated diene-based monomer include:
1,3-butadiene, 2-methyl-1,3-butadiene, 2,3
One or more aliphatic conjugated diene-based monomers such as dimethyl-1,3-butadiene and chloroprene are used. The amount of the conjugated diene-based monomer used in all the monomers is usually 45 to 95% by weight, and if it is out of this range, the adhesive force between the rubber and the fiber is lowered. It is preferably 60 to 75% by weight.

As the aromatic vinyl compound, styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4
-Methylstyrene, 2,4-diisopropylstyrene, 2,4
-Dimethylstyrene, 4-t-butylstyrene, 5-t
-Butyl-2-methylstyrene, monochlorostyrene,
One or more of dichlorostyrene, monofluorostyrene, hydroxymethylstyrene and the like are used. The amount used in all monomers is 0 to 30% by weight.

As vinyl pyridine, 2-vinyl pyridine is preferable, but it is used in combination with one or more of 3-vinyl pyridine, 4-vinyl pyridine, 2-methyl-5-vinyl pyridine, 5-ethyl-2-vinyl pyridine or the like. These can be replaced by one kind or two or more kinds.

The amount of vinyl pyridine monomer used in all the monomers is 5 to 40% by weight, and if the amount is out of this range, the adhesive strength will be reduced.
It is preferably 10 to 30% by weight.

In addition to the above monomers as required, acrylonitrile; vinyl chloride; ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid; ethyl acrylate,
At least one kind of ester of ethylenically unsaturated carboxylic acid such as methyl methacrylate and 2-ethylhexyl acrylate can be used up to 30% by weight in the total amount of all monomers.

The vinyl pyridine-based polymer latex used in the present invention is produced by ordinary emulsion polymerization, but in order to achieve the object of the present invention, the unreacted residual vinyl pyridine monomer in the polymer latex is The content needs to be 0.2% by weight or less based on the weight of the total solid content in the polymer latex. 0.2% by weight of residual vinyl pyridine monomer
If it exceeds, it is impossible to prevent the strength of the fiber from being lowered when the fiber is treated with the polymer latex. Preferably 0.15% by weight
The amount is below, more preferably 0.05% by weight or less.

The method for producing the polymer latex and the method for reducing the residual vinylpyridine monomer used in the present invention are not particularly limited.

The polymerization may be batch emulsion polymerization, semi-batch emulsion polymerization or continuous emulsion polymerization, and the polymerization temperature may be either low temperature or high temperature. Also, an emulsifier used for polymerization, a polymerization initiator,
The molecular weight modifier and the like may be those used in ordinary emulsion polymerization and are not particularly limited.

Examples of emulsifiers include nonionic surfactants such as polyethylene glycol alkyl ester type, alkyl phenyl ether type, alkyl ether type, and higher alcohol sulfates; anionic surfactants such as alkylbenzene sulfonates and aliphatic sulfonates. One or more amphoteric surfactants such as betaine type are used.

As the polymerization initiator, for example, a water-soluble initiator such as potassium persulfate or ammonium persulfate, a redox-based initiator, or an oil-soluble initiator such as benzoyl peroxide can be used.

As the molecular weight modifier, mercaptans, xanthogen disulfides, halogenated hydrocarbons and the like can be used.

One way to reduce the content of residual vinyl pyridine monomer is to remove the residual monomer from the polymer latex after emulsion polymerization. To remove the monomer, it is effective to treat the polymer latex under reduced pressure while heating. Practically, it is desirable to adopt the conditions of temperature of 30 to 90 ° C and pressure of 10 to 600 Torr. In addition to this, it is also possible to increase the polymerization conversion rate by continuing the polymerization reaction for a long time to reduce the residual monomer, or to heat under normal pressure to reduce the residual monomer.

The vinyl pyridine polymer latex thus obtained is used as an adhesive between fibers and rubber according to a conventional method.

(Effect of the invention) Thus, when treating the polyester fiber, by using a polymer latex in which the amount of residual vinyl pyridine monomer is 0.2% by weight or less of the total solid content in the polymer latex, the conventional polymer latex can be obtained. The strength of the fiber is remarkably improved as compared with the use of.

(Example) Hereinafter, the present invention will be described more specifically with reference to Examples. The parts and% in the examples and comparative examples are based on dry weight unless otherwise specified.

Example 1 90 parts of water, 2 parts of potassium rosinate, 0.5 parts of sodium naphthalenesulfonate, 0.15 parts of potassium hydroxide, 0.5 parts of t-dodecyl mercaptan, 70 parts of butadiene, 15 parts of styrene, and 2-vinylpyridine in an autoclave equipped with a stirrer. After charging 15 parts and raising the temperature to 60 ° C., 0.3 parts of potassium persulfate was charged together with 10 parts of water. When the weight conversion reached 40%, 1 part of potassium rosinate was added to the autoclave together with 3 parts of water. Further, when the polymerization conversion rate reached 60%, 1 part of potassium rosinate was added together with 3 times of water. Polymerization conversion rate of 80%
2 parts potassium rosinate was added along with 6 parts water. Hydroquinone 0 when polymerization conversion reached 95%.
The reaction was stopped by adding 05 parts to obtain latex A. The residual vinyl pyridine content of Latex A was measured using Hitachi Gas Chromatography Model 263-50.
The measurement conditions were liquid phase PEG-20M. Column temperature 125 ° C and FID. As a result of the measurement, the content of vinylpyridine monomer was 0.35% by weight based on the total solid content in the latex.

Next, the latex A was placed in a glass separable flask equipped with a stirrer and immersed in a water temperature bath. Liquid temperature of latex is 60
While keeping the temperature at 0 ° C., one side was introduced into a trap cooled with a pressure-resistant rubber hose, and further introduced into a vacuum pump to hold the separable flask at 160 Torr to perform a monomer removal operation for 2 hours. This is designated as latex B. Latex B has a residual vinyl pyridine monomer content of 0.009
%Met.

Next, 16.6 parts of resorcinol, 14.6 parts of formalin aqueous solution (37% concentration), and 1.3 parts of sodium hydroxide were dissolved in 333.5 parts of water, and reacted at 25 ° C. for 2 hours with stirring. Then, 100 parts of latex (see Table 2) was added to this, and the mixture was stirred with stirring.
The reaction was carried out at 0 ° C for 20 hours. Then Vulcabond E (Vulnax In
ternational Ltd.) was added. A polyester cord (1500d / 2) was immersed in this aqueous solution using a single cord dipping machine. After the immersion treatment, heat treatment was performed at 240 ° C. for 1 minute.

The strength of this adhesive treatment cord was measured according to JIS L-1017.

Next, the adhesive treatment cord was sandwiched between natural rubber compounds produced according to the compounding recipe shown in Table 1 and press-vulcanized at 150 ° C. for 30 minutes. The adhesive force between the tire cord and the rubber was measured by the T-adhesion test method (measurement temperature 20 ° C., relative temperature 65%, pull-out test of 24 wires).

The above results are shown in Table 2.

Table 1 Rubber compounding composition formulation Natural rubber 100 parts Zinc white 5 〃 Stearic acid 5 〃 Sulfur 2.5 〃 FEF carbon black 45 〃 Process oil 5 〃 N-oxydiethylene-2-benzothiazyl sulfenamide 1 〃 2,2 1,4-trimethyl-1,2-dihydroquinoline polymer 1 〃 Example 2 Latex C to F shown in Table 3 were produced by operating in the same manner as in Example 1 except that the final polymerization conversion rate during the production of the latex and the operating conditions for removing the residual monomer were appropriately changed. Polyester tire cords were treated in the same manner as in Example 1 using the obtained latexes C to F, and the cord strength and adhesive strength were measured. The measurement results are shown in Table 3.

From the results shown in Tables 2 and 3, treatment with a vinylpyridine-based polymer latex in which the content of the residual vinylpyridine monomer in the polymer latex is 0.2% by weight or less of the total solid content in the polymer latex is performed. As a result, it can be seen that a rubber-reinforced polyester fiber having an improved cord strength can be obtained.

Claims (1)

[Claims] 1. The content of residual vinylpyridine monomer in the polymer latex is 0.2% of the total solid content in the polymer latex.
A method for producing a polyester fiber for rubber reinforcement having improved cord strength, which comprises treating with a vinylpyridine polymer latex in an amount of not more than 10% by weight.