JP2002004139A - Method for producing glass fiber cord for rubber reinforcement and rubber product containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing glass fiber cord for rubber rein forcement, having high integrity and resistance to deterioration by bending fatigue and deadhesion of resorcin-formaldehyde resin rubber latex, and provide a rubber product having high tensile strength and flexural fatigue by reinforcing with the glass fiber cord. SOLUTION: This method for producing the glass fiber cord comprises applying rubber latex mixed liquid of resorcin-formaldehyde resin to strand of glass fiber, heat-drying the coated strand at 80-150 deg.C, paralleling plural strands and twisting the strands and heat-treating the resultant cord in 0.3-2.0 g/Tex tension at 200-300 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a glass fiber cord which is embedded in a rubber product and has improved strength and dimensional stability.

[0002]

2. Description of the Related Art If glass fibers are coated with a resorcinol-formaldehyde resin latex (hereinafter referred to as "RFL"), mutual abrasion between the glass fibers is suppressed, and various factors such as bending fatigue of rubber products in which the glass fibers are embedded are suppressed. It is known that physical properties are improved. For example, Japanese Patent Publication No. 48-11599
In the publication, a suitable amount of a sizing agent is attached to a glass fiber strand, treated with an RFL mixed solution, untwisted, heated to 110 ° C or lower, and further heated to 110 to 230 ° C.
It is described that a glass fiber cord excellent in mechanical performance and adhesion to rubber can be obtained by baking. Japanese Patent Publication No. 49-40627 discloses that a glass fiber having a twist of 0.7 turns / inch or less is treated with an RFL dispersion liquid, and this is twisted at 20 turns / inch.
Treated with FL dispersion, tension 1.0 g / d (2.22 g / Tex),
A method for producing a glass fiber cord for rubber reinforcement dried at 175 ° C. is described.

[0003]

[Problems to be solved by the invention]
The glass fiber cord described in JP-A-11599 is twisted without twisting, and thus has a high tensile strength, but has a problem of poor integrity and low bending fatigue resistance. Further, the glass fiber cord described in JP-B-49-40627 has a low heating temperature for fixing the RFL to the glass fiber, so that the polymerization of the RFL is not sufficient, and as a result, the glass fiber and the RFL are easily peeled off. There was a problem.

[0004] The present invention has been made in view of such problems in the prior art. The purpose is to spread the RFL over the entire strand of glass fiber and firmly fix it, so that the strength of the glass fiber cord for rubber reinforcement is high and the strength is not easily degraded due to bending fatigue or the RFL is hardly peeled off. It is to provide a manufacturing method. Another object of the present invention is to provide a rubber product having extremely high tensile strength and bending fatigue by embedding the glass fiber cord as a reinforcing material.

[0005]

According to a first aspect of the present invention, there is provided a method for producing a glass fiber cord for rubber reinforcement, comprising the step of: mixing a resorcinol-formaldehyde resin rubber latex mixture on a glass fiber strand. It is applied and dried by heating at 80 to 150 ° C., a plurality of the strands are aligned and twisted, and a tension of 0.3 to 2.0 g / Tex, 2
The heat treatment is performed at 00 to 300 ° C.

The rubber product according to the second aspect of the present invention contains a glass fiber cord produced by the method according to the first aspect.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail.

[0008] The steps up to processing the spun glass filament into a glass fiber cord for rubber reinforcement are roughly divided into the following four. First step: The molten glass is spun and wound as a strand. Second step: Apply the RFL mixture to the strand,
Dry in an environment of 0 to 150 ° C. Third step: A plurality of dried strands are bundled and twisted. Fourth step: After twisting, the glass fiber is coated with 0.3-2.
While applying a tension of 0 g / Tex, heat treatment is performed in an environment of 200 to 300 ° C.

In the first step, 200 to 1,000 glass filaments having an average diameter of 5 to 20 μm are bundled and wound as a strand. During spinning, a sizing agent may be applied to the glass filament. As the sizing agent, a mixture obtained by adding an aminosilane or a lubricating oil to a silane coupling agent is preferable. The strands may be twisted, but preferably are in a non-twisted state while being spun and bundled. When the RFL mixture is applied in the second step, R
This is because FL easily penetrates into the inside of the strand.

Next, in the second step, an appropriate amount of the RFL mixed solution is applied, but the application method is not particularly limited, and a known method such as a spraying method, a roller coating method, and a dipping method can be used. . Among them, the immersion method is most preferable because the RFL easily spreads uniformly over the entire strand and the amount of adhesion is easily adjusted. As a specific usage mode of the immersion method, a method of once immersing the strand in a tank filled with the RFL mixed solution, passing the strand, and removing the dripping RFL mixed solution, and the like can be mentioned. The solids deposition rate of the RFL is 15 to 25 based on the weight of the strand after deposition.
% By weight is preferred. If less than 15% by weight, RFL
Does not spread sufficiently between the glass filaments, and mutual friction between the glass filaments is likely to occur. On the other hand, if it exceeds 25% by weight, it takes time to heat and dry the RFL mixed solution, and there is a possibility that the homogeneity of the strand is impaired, for example, a portion having a large amount of adhesion is easily formed locally. The strand coated with RFL is 80 to 150 ° C.
Heat treatment under the environment of When the environmental temperature is lower than 80 ° C., the polymerization of the RFL does not proceed so much and the solvent is hardly evaporated, so that the RFL easily flows out without adhering to the glass filament. On the other hand, if the temperature exceeds 150 ° C., the solvent evaporates too quickly, bubbles are generated between the glass filaments, and the integrity of the strand is reduced. Also, RF
The polymerization of L proceeds excessively, and the adhesion between the strands in the fourth step becomes insufficient. A more preferable ambient temperature is
100-130 ° C. The time of the heating and drying treatment cannot be determined unconditionally because it depends on the number of bundles of glass filaments, the RFL concentration or the amount of adhesion, etc.
When 0% by weight of RFL is deposited at a solids deposition rate of 20% by weight, the time is preferably 15 to 60 seconds. This is the range that became clear for the first time from the results of many experiments by the present inventors.

RFL is a mixture of the reaction product of resorcinol and formaldehyde with rubber latex.
Examples of the rubber latex include natural rubber, styrene / butadiene copolymer, styrene / butadiene / vinylpyridine copolymer, butadiene / acrylonitrile copolymer, butyl rubber, chlorobrene rubber, neobrene rubber, calxylated butadiene / styrene copolymer or chlorinated rubber. Examples thereof include sulfonated polyethylene. The rubber latex may be a mixture of two or more of the above, or may coexist in a reaction system for reacting resorcinol and formaldehyde before the reaction. RFL is diluted with water to obtain a solid concentration of 1
It is preferable to adjust the amount to 5 to 30% by weight and ripen it for several days after the production.

In the third step, a plurality of strands are bundled and twisted, but the number of bundles and the number of twists are not particularly limited. However, from the viewpoint of the balance between tensile strength and flex fatigue, the number of priming twists is 1.0 to 4.0 times / 25 mm, the number of bundled filaments is 1,800 to 12,000, and the number of ply twists is 1.0.
~ 4.0 times / 25mm is preferred. The bundle of strands is twisted (in the case of sub-twisting, indicates a top-twisting), thereby increasing its integrity. That is, if the twist is not applied, the strands are restricted only by the adhesion of the RFL by the heat treatment in the fourth step. Due to the high degree of integrity, the performance of the glass fiber cord hardly deteriorates due to bending fatigue. On the other hand, the strand is easily deformed (elongated) due to the twist, but not so much as to exceed the deformability of the rubber product to be reinforced.

In the fourth step, the twisted yarn of the strand is heat-treated at 200 to 300 ° C. while applying a tension of 0.3 to 2.0 g / Tex. By performing the heat treatment at an appropriate tension and temperature, the RFL attached to each strand is polymerized, and the strands of the strands are integrated to form a glass fiber cord for rubber reinforcement. If this tension is less than 0.3 g / Tex, the binding of the twisted strand of the strand is loosened, and its integrity is impaired. On the other hand, if it exceeds 2.0 g / Tex, RFL that has permeated between the glass filaments is squeezed out, and R
Adhesion by FL will be reduced. On the other hand, when the ambient temperature is lower than 200 ° C., the heat is not easily transmitted to the inside of the twisted yarn of the strand, and the polymerization of the RFL inside tends to be insufficient. On the other hand, when the temperature exceeds 300 ° C., the RFL on the surface layer of the twisted strand of the strand is likely to be modified. This heat treatment is performed using a hot-air circulation furnace for a processing time of 30 to 12 hours.
0 seconds is appropriate.

The glass fiber cord is embedded in various rubber products by a known method, and improves the tensile strength and flex fatigue resistance of the rubber product. The type of rubber product is not particularly limited, but a timing belt that requires high tensile strength and flex fatigue resistance is suitable. Further, the rubber matrix of the rubber product is preferably the same as the rubber latex of the above-mentioned RFL from the viewpoint of adhesion to the glass fiber cord.

[0015]

The present invention will be described more specifically below with reference to examples and comparative examples.

(Example 1) Resorcinol 8 parts by weight, concentration 3
12 parts by weight of 7% by weight of formalin, 200 parts by weight of styrene / butadiene / vinylpyridine / terpolymer latex having a solids content of 40% by weight and 230 parts by weight of water are mixed and aged sufficiently to obtain a solid content of 20%. A weight percent RFL mixture was prepared. This was applied by dipping to three non-twisted strands (ECG150) having a count of 150 to form a solid adhesion rate of 20% by weight. Immediately thereafter, the bundle of strands was put into a hot-air circulating drying oven set at 100 ° C., and passed through the oven for 35 seconds (hereinafter, this heat treatment is referred to as “heat treatment 1”). Subsequently, the number of twists of this bundle of strands is 4.
Twisting was performed at 0 times / 25 mm, and 13 pieces were combined and twisted at 2.0 times / 25 mm in the opposite direction to the twisting. And 0.6g
While applying a tension of / Tex, the glass fiber cord was passed through a hot air circulating drying oven set at 230 ° C. for 70 seconds (hereinafter, this heat treatment is referred to as “heat treatment 2”) to produce a glass fiber cord for rubber reinforcement. Note that the ECG 150 is a size composition comprising an RFL mixed solution, an aminosilane A1100, and a lubricating oil, the mixing ratio of which is adjusted with the same composition component as the RFL,
It is a non-twisted strand applied so as to have a solid content of 0.5% by weight.

With respect to this glass fiber cord, the bending abrasion, adhesion, tensile strength and dimensional stability (rate of change) were measured by the following methods. The results are shown in Table 1 below. Flex wear (times): A load is applied to one end of a glass fiber cord, and it is repeatedly bent at a constant angle and a constant speed using a predetermined jig, and the number of times of bending until breakage is measured. Adhesion (kg / 25 mm): Glass fiber cords were arranged on a rubber matrix having a width of 25 mm without any gap, and one end thereof was adhered under predetermined vulcanization conditions. The other end of the glass fiber cord, which was not adhered, and the rubber matrix were individually fixed to a jig, a load was applied so as to tear them, and the peel strength at that time was measured. Tensile strength (kg / piece): The load when the glass fiber cord was broken was measured using a constant load speed tester (Autograph manufactured by Shimadzu Corporation). Dimensional change (%): A load of 20 kg was applied to the glass fiber cord, and the elongation at that time was measured.

(Example 2) In the heat treatment 2, a glass for reinforcing rubber was prepared in the same manner as in Example 1 except that the set temperature in the hot air circulating drying oven was set to 250 ° C and the strands of the strand were passed over 50 seconds. A fiber cord was manufactured. The physical properties of this glass fiber cord were measured in the same manner as in Example 1. The results are shown in Table 1 below.

(Example 3) In the heat treatment 2, a glass for reinforcing rubber was prepared in the same manner as in Example 1 except that the set temperature in the hot air circulating drying oven was set to 275 ° C and the strands of the strand were passed over 35 seconds. A fiber cord was manufactured. The physical properties of this glass fiber cord were measured in the same manner as in Example 1. The results are shown in Table 1 below.

Comparative Example 1 A twisted strand was produced in the same manner as in Example 1 except that the heat treatment 2 was not performed. Further, in the same manner as in Example 1, the physical properties of the twisted strand were measured. The results are shown in Table 1 below.

(Comparative Example 2) In the heat treatment 1, the set temperature in the hot air circulating drying furnace was set to 90 ° C., and the strands were not twisted or twisted. A glass fiber cord for rubber reinforcement was manufactured in the same manner as in Example 1 except that the time was set to 35 seconds. The physical properties of this glass fiber cord were measured in the same manner as in Example 1. The results are shown in Table 1 below.

(Comparative Example 3) In the heat treatment 1, the furnace temperature was set to 85 ° C, and in the heat treatment 2, the furnace temperature was set to 175 ° C, the passage time was 90 seconds, and the strand tension was 2.22 g / Tex. In the same manner as in Example 1, a glass fiber cord for rubber reinforcement was produced. The physical properties of this glass fiber cord were measured in the same manner as in Example 1. The results are shown in Table 1 below.

[0023]

[Table 1]

[0024]

According to the present invention having the above-described structure, the following effects can be obtained. According to the first aspect of the present invention, since the RFL spreads over the entire strand of the glass fiber and is firmly fixed, the glass fiber cord for rubber reinforcement has high integrity and hardly causes strength deterioration due to bending fatigue, peeling of the RFL, and the like. Is surely obtained.

According to the second aspect of the present invention, a rubber product having extremely high tensile strength and bending fatigue resistance can be obtained by embedding the glass fiber cord as a reinforcing material.

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Claims (2)

[Claims] (1) Resorcinol is added to a glass fiber strand.
Apply a formaldehyde resin rubber latex mixture,
A method for producing a glass fiber cord for rubber reinforcement, wherein the strand is heated and dried at 80 to 150 ° C, a plurality of the strands are aligned, twisted, and heat-treated at a tension of 0.3 to 2.0 g / Tex at 200 to 300 ° C. 2. A rubber product containing a glass fiber cord produced by the method according to claim 1.