JP2000226776A - Production of rubber hose-reinforcing fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing the subject fibers consisting of polyphenylene sulfide fibers highly adhesive to ethylene-propylene-nonconjugated diene-based copolymer rubber (EPDM). SOLUTION: This method for producing the subject fibers comprises treatment of polyphenylene sulfide fibers single-twisted at <=200 turns/m with a 1st agent comprising (A) a cresol-novolak-type polyepoxide and (B) a rubber latex followed by a 2nd agent comprising a mixture of (C) an initial condensate of resorcinol-formaldehyde and (D) a rubber latex.

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 rubber hose reinforcing fiber comprising a polyphenylene sulfide fiber used for reinforcing a rubber hose, and more particularly, to a method for producing an ethylene / propylene / non-conjugated diene copolymer. The present invention relates to a method for producing a rubber hose reinforcing fiber having excellent adhesion to a rubber compound represented by a compounded rubber (hereinafter sometimes referred to as EPDM) -based compound.

[0002]

BACKGROUND ART As reinforcing materials for rubber hoses for automobiles such as hoses for radiators, synthetic fibers such as polyamide fibers typified by hexamethylene adipamide, polyester fibers typified by polyethylene terephthalate, polyvinyl alcohol fibers, and rayon fibers. Fibers have been commonly used in the past.

The required performance of reinforcing fibers used in the rubber hoses for automobiles is described in
As described in Japanese Patent No. 159882, the strength, the initial tensile resistance (apparent Young's modulus) are high, and the material has mechanical properties that are unlikely to undergo creep deformation, and also has heat resistance, thermal (oxidation) durability, and mechanical fatigue resistance. Required to have.

[0004] On the other hand, polyphenylene sulfide fiber is a material excellent in heat resistance, acid resistance, alkali resistance and the like, but is extremely poor in adhesiveness to rubber. It was considered difficult to use for

For example, JP-A-63-92776 discloses that a polyester fiber previously treated with a first treating agent containing an epoxy compound is mixed with a mixture of a resorcinol-formaldehyde initial condensate and a rubber latex, an ethylene urea compound. , A method of treating with a second treating agent containing a cresol novolak type polyepoxide and an inorganic oxide. Also, JP-A-7-216755, JP-A-7-238473, and JP-A-7-25
JP-A-8975 and JP-A-10-2738808 disclose that after treating a polyester fiber with a first treating agent containing a polyepoxide compound, an initial condensate of resorcinol / formaldehyde and styrene / butadiene / vinylpyridine terpolymer are obtained. A method for treating polyester fibers using a treating agent in which a mixed latex of latex and polybutadiene latex, blocked isocyanate, and chlor-modified resorcinol are mixed at a specific blending ratio is disclosed. However, even with the application of these methods, it has been difficult to ensure sufficient adhesion between the polyphenylene sulfide fiber and the EPDM rubber compound required for reinforcing the rubber hose.

[0006]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of studying to solve the problems in the prior art described above. Therefore, the object of the present invention is to
In particular, it is an object of the present invention to provide a method for producing a rubber hose reinforcing fiber composed of polyphenylene sulfide fiber having excellent adhesion to an EPDM rubber compound.

[0007]

Means for Solving the Problems In order to achieve the above object, the method for producing a rubber hose reinforcing fiber of the present invention mainly has the following constitution. That is, a polyphenylene sulfide fiber that has been subjected to a single twist of 200 times or less per 1 m is treated with a first treating agent containing a cresol novolak type polyepoxide (A) and a rubber latex (B),
Subsequently, a method for producing a rubber hose reinforcing fiber is characterized in that the fiber is treated with a second treating agent containing a mixture of a resorcinol-formaldehyde initial condensate (C) and a rubber latex (D).

[0008] In the present invention, the following (1) to
The condition (5) is a preferable condition, and the application of these conditions can be expected to obtain a better effect. (1) The compounding ratio of the cresol novolak type polyepoxide (A) and the rubber latex (B) as the first treating agent is 90:10 to 20:80 in terms of solid content weight ratio,
(2) The rubber latex (B) contained in the first treating agent is
A rubber latex containing a vinyl pyridine-styrene-butadiene terpolymer latex; (3) a solid content of the first treatment agent of 0.5 to 3.0% by weight with respect to the fiber; (4) After adhering the first treatment liquid to the fiber, heat-treat it at a temperature of 80 to 240 ° C.
After the treatment liquid is applied, heat treatment is performed at a temperature of 200 to 260 ° C. (5) The rubber hose is a rubber hose made of EPDM.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration and effect of the present invention will be described below in detail. In the method for producing a fiber for reinforcing a hose of the present invention, a so-called 2
It is an essential condition to perform a bath treatment.
It is important to first treat the surface of the fiber that has been subjected to zero or less real twists with a first treating agent containing a cresol novolak type polyepoxide (A) and a rubber latex (B).

The cresol novolak type polyepoxide (A) used in the present invention is a glycidyl ether type phenol resin represented by the following formula. The epoxy equivalent of the cresol novolak type polyepoxide (A) is preferably 1500 or less, particularly preferably 700 or less. The reason is that if the epoxy equivalent is in such a range, it becomes easy to secure the adhesiveness.

Embedded image

The first treating agent of the present invention contains a rubber latex (B) at the same time, whereby high adhesiveness to rubber can be ensured. When cresol novolak type polyepoxide (A) is used as the first treating agent, high adhesion to rubber is obtained because cresol novolak type polyepoxide (A) is more polyphenylene sulfide fiber than polyglycidyl ether type polyepoxide. However, it is presumed that, due to the surface energy close to that of polyphenylene sulfide, these fibers are easily diffused between single yarns or the inner layer of the fiber structure, and mechanical adhesion is obtained.

The effect of improving the adhesion to rubber of the present invention is remarkable when the fiber is a single twisted fiber of 200 times or less per meter, and when the number of twists is larger than this range, In the case where a plurality of fibers that have been subjected to priming as used in tire cords are aligned and twisted in the opposite direction to the priming, the effect of improving the adhesion to rubber is extremely high. Become smaller.

However, the cresol novolak-type polyepoxide (A) alone does not have sufficient adhesiveness between the first and second treatment agent layers of the finally obtained rubber hose reinforcing fiber, and the first treatment agent is a rubber. It is necessary to contain latex (B). And, when the latex (B) contained in the first treating agent contains the same type of rubber latex component as the rubber latex (D) contained in the second treating agent, the adhesiveness to rubber becomes highest.

The rubber latex (B) used in the present invention
As the rubber latex component, a vinylpyridine / styrene / butadiene terpolymer latex having excellent heat resistance is preferably 50% by weight or more in a rubber latex component, and a cresol novolak type polyepoxide (A) and a rubber latex (B) are preferred. The solid content weight ratio (A: B) is 90:10 to 2
The ratio is preferably in the range of 0:80, particularly 80:20 to 50:50. By setting the content in this range, a fiber having excellent adhesion to the EPDM rubber compound can be obtained.

In the method for producing a hose reinforcing fiber according to the present invention, it is necessary that the second treating agent contains a mixture of an initial condensate (C) of resorcinol / formaldehyde and a rubber latex (D), By treating with the second treatment agent after the first treatment agent, the desired effect of improving the adhesion to rubber can be obtained for the first time.

The precondensate (C) of resorcinol / formaldehyde used in the present invention has a molar ratio of resorcinol to formaldehyde of 1/1 to 1/3, especially 1/1.
/2.0 is preferable. By setting the amount of formaldehyde in the above range, it is possible to prevent the generation of sticky scum in the hose manufacturing process, and to maintain the smoothness of the fiber and to reduce the frictional force of the fiber. on the other hand,
The finish of the fiber can be kept soft without excessively progressing the three-dimensional reaction.

The precondensate (C) of resorcinol-formaldehyde is reacted in a resole form in which an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is used as a catalyst or in an acidic catalyst such as oxalic acid or hydrochloric acid. Although there is a novolak type, any one can be used in the present invention. When particularly high adhesiveness is required, a novolak-type resorcinol-formaldehyde condensate is preferably used.

The solid content weight ratio (C: D) of the precondensate (C) of resorcinol / formaldehyde to the rubber latex (D) is from 34:66 to 12:88, especially 20: 8.
It is preferably in the range of 0 to 15:85. By setting the proportion of the resorcinol-formaldehyde precondensate (C) in the above range, the fibers can be kept soft.
On the other hand, the handleability in the hose manufacturing process can be maintained favorably without the fibers having too high tackiness.

When the second treating agent further contains para-chlorophenol-resorcin-formaldehyde co-condensate (E), higher adhesion to rubber and smoothness can be obtained. The parachlorophenol / resorcin / formaldehyde cocondensate (E) as used herein refers to a compound containing the following general formula as a main component.

Embedded image However, in the above general formula, n represents 0 or an integer of 1 to 10.

A specific example of the compound represented by the above general formula is 2,6-bis (2 ', 4'-dihydroxy-phenylmethyl) -4-chlorophenol (trade name: "VALCABOND E" (registered trademark)) , "Kasabond" (registered trademark), "Denabond" (registered trademark) and the like.
Among them, it is preferable to use a parachlorophenol / resorcin / formaldehyde cocondensate having a small content of a free parachlorophenol component represented by "Denabond E".

In this case, the weight ratio (C: D) of the initial condensate (C) of resorcinol / formaldehyde contained in the second treating agent and the rubber latex (D) is 34:66.
The solid content weight ratio of the initial condensate of resorcinol / formaldehyde (C), the co-condensate of parachlorophenol / resorcinol / formaldehyde (E), and the rubber latex (D) is preferably: C
+ E) / D = 60/40 to 40/60. When the content is in the above range, a fiber that can simultaneously satisfy the adhesiveness to the EPDM rubber compound, the flexibility and smoothness of the fiber, and the reduction of the treatment agent residue in the hose manufacturing process can be obtained. A further preferred range is that C: D is 20: 80-
25:75, (C + E) / D is 55 / 45-45 / 55.
Is the case.

Further, a blocked polyisocyanate compound (F) can be added to the second treating agent. The blocked polyisocyanate compound (F) is a compound in which a blocking agent is released by heat to produce an active isocyanate compound. Specifically, tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate , Polyisocyanate compounds such as triphenyl methane triisocyanate, phenols such as phenol, cresol and resorcinol, lactams such as ε-caprolactam and valerolactam, oximes such as acetoxime, methyl ketyl ketone oxime and cyclohexane oxime, ethylene Reaction products with a blocking agent such as imine, among which cresol novolak-type polyisocyanate compound blocked with ε-caprolactam and The use of cresol novolak type compounds of diphenylmethane diisocyanate is preferred.
When the blocked isocyanate (F) is added, the solid content of 1 to 20% by weight, preferably 3 to 10% by weight of the total of the solid content of the resorcinol-formaldehyde initial condensate (C) and the rubber latex (D) is added. It is good to make it the addition amount.

The polyphenylene sulfide fiber is obtained by melt-spinning a polyphenylene sulfide resin produced by a conventional method. For example, a polyphenylene sulfide resin obtained by reacting parachlorobenzene with sodium difluoride at 200 to 250 ° C. in N-methyl-pyrrolidone and removing the solvent can be used. In particular, the polyphenylene sulfide fiber has a strength of 4.5 g / d or more and an initial tensile resistance of 6 g / d.
It is preferable that the dry heat shrinkage at 180 ° C. is 8% or less and 5 g / d or more.

The polyphenylene sulfide resin used as a raw material of the polyphenylene sulfide fiber is as follows:
Preferably, the polymer is a substantially linear polymer having a melt flow rate (MFR) of 100 to 600, but may be a crosslinked polymer containing 0.1% by weight or less of trichlorobenzene (TCB). Here, the melt flow rate (MFR) refers to a measurement temperature of 316 ° C. and a load of 5 kgf.
Means the melt flow of the polymer as measured by ASTM D1238-70 method.

The polyphenylene sulfide used includes various inorganic particles such as titanium oxide, silicon oxide, calcium carbonate, silicon nitride, clay, talc, kaolin and zirconate, crosslinked polymer particles, and various metal particles. In addition to the above, conventionally known antioxidants, sequestering agents, ion exchange agents, coloring inhibitors, waxes, silicone oils, various surfactants, and the like may be added.

The solid content of the treating agent on the fiber may be 0.5 to 3.0% by weight, preferably 1.0 to 3.0% by weight of the first treating agent.
It is appropriate to deposit 2.0% by weight, and 1.0 to 4.0% by weight, preferably 1.5 to 3.0% by weight, of the second treating agent. As a method of causing the treatment agent to adhere to the fibers, any method such as contact with a roller, spraying from a nozzle, or immersion in the treatment agent can be adopted.

In the present invention, for example, 2
After first applying the first treating agent to the polyphenylene sulfide fiber having been twisted no more than 00 times,
After heat treatment at 40 ° C., preferably 110 to 220 ° C. for 0.5 to 3 minutes, and subsequently applying the second treating agent,
0 to 260 ° C, preferably 0.5 to 220 to 240 ° C
A method of heat treatment for 3 minutes is used.

By setting the heat treatment temperature after the application of the first and second treatment agents within the above range, good adhesion to rubber can be obtained, while the fibers after vulcanization are soft and flexible. A rich hose is obtained. Furthermore, by adding a known mechanical softening to the fiber after the heat treatment and crushing the treatment agent film on the fiber surface, the fiber before and after vulcanization can be finished to be flexible. This mechanical softening is desirably performed under a tension of 0.1 to 0.5 g / d per fiber. Further, as described in JP-A-7-145567, a temperature of 60 to 120 ° C and a temperature of 0.05 to 0.15 g /
By performing a low-temperature heat treatment under a tension of d for 30 to 180 seconds, a softer fiber can be obtained.

Thus, the polyphenylene sulfide fiber for reinforcing rubber hose obtained by the production method of the present invention has good adhesiveness to rubber and is suitable for reinforcing rubber hoses such as radiator hoses, heater hoses, heater bypass hoses, and fuel hoses. Can be used.

[0030]

The present invention will be described more specifically with reference to the following examples. In addition, each measurement value in an Example is calculated | required by the following method. [Melt viscosity index of polyphenylene sulfide] ASTM D 1 using a melt flow tester manufactured by Shimadzu Corporation
It was measured according to the standard of 238-70. [Treatment agent adhesion amount] JIS L 1017 (1995)
By the mass method. [Adhesion with EPDM] Peel adhesion was used as an index. That is, the fiber is wound around an aluminum plate so that there is no gap, EPDM is stuck on both sides of the aluminum plate, press vulcanization is performed at 150 ° C. for 60 minutes, and after cooling, 50 ° C. in an environment of 20 ° C.
The peeling load when the fiber was peeled from the rubber at a speed of mm / min was expressed in N / inch. The rubber coverage was determined by visually observing the fibers peeled off from the rubber at the time of the above-mentioned peel adhesion measurement, and expressing the portion where the rubber adhered to the fiber surface in percentage. The compounding composition of the rubber used in the evaluation is as follows. EPDM 100.0 parts Zinc white 5.0 parts Stearic acid 1.0 parts Carbon black 80.0 parts Processing oil 0.3 parts Sulfur 1.5 parts 2-mercaptobenzothiazole 0.5 parts Tetramethylthiuram disulfide 1.0 Department

Example 1 As a first treating agent, orthocresol novolac type polyepoxide "Denacol EM150" (A) manufactured by Nagase Kasei Kogyo Co., Ltd. and vinylpyridine styrene manufactured by Sumika ABS Latex Co., Ltd. -Butadiene terpolymer copolymer latex "pylatex FS" (B) was mixed so that A: B was 50:50 in terms of solid content weight to prepare a solid content concentration of 10% by weight. As the second treating agent, an initial condensate (C) of resorcinol-formaldehyde obtained by reacting 2.0 mol of formaldehyde with 1.0 mol of resorcinol, and vinylpyridine manufactured by Sumika ABS Latex Co., Ltd.・
A rubber latex (D) obtained by mixing a styrene / butadiene terpolymer latex "Pyrexate FS" and a polybutadiene latex "LX111A2" manufactured by Zeon Corporation in a ratio of 50:50 in terms of solid content weight ratio is mixed, Aged for 24 hours. At this time, a novolak-type precondensate ("Sumikanol 700S" manufactured by Sumitomo Chemical Co., Ltd.), which was obtained by precondensing resorcinol and formaldehyde at a molar ratio of resorcinol / formaldehyde = 1 / 0.65 in advance under an acidic catalyst, After dissolving in water in which sodium hydroxide is dissolved, formaldehyde is additionally added. The treatment agent contains the parachlorophenol / resorcin / formaldehyde cocondensate (E),
A compound represented by the general formula [Chemical Formula 2] (E: manufactured by Nagase Kasei Kogyo Co., Ltd .: “Denabond E”) is mixed so that (C + E) / D = 50/50 in terms of solid content weight ratio. , Blocked isocyanate “DM60A” manufactured by Meisei Chemical Co., Ltd.
(F) is added to the total solid content of the resorcinol-formaldehyde precondensate (C) and the rubber latex (D) by 1%.
0% by weight, and the liquid solid content concentration is 20% by weight.
Was prepared.

The melt viscosity index (MFR value) is 54 g / 10
The polyphenylene sulfide resin pellets are melt-spun and drawn by a conventional method using a polyphenylene sulfide resin (1000 denier / 2, manufactured by Toray Industries, Inc.).
00 filament) 5 times /
m to obtain a cord. This cord was immersed in the first treatment liquid using a Ritzler Computorator and heat-treated at 150 ° C. for 60 seconds. Subsequently, the substrate was immersed in the second processing solution and heat-treated at 240 ° C. for 60 seconds. Table 1 shows the characteristic evaluation results of the processing codes thus obtained.

[0033]

[Table 1]

Examples 2-3 and Comparative Examples 1-3 First
The test was carried out in the same manner as in Example 1 except that the epoxy species used for the treating agent and the mixing ratio of the epoxy compound and the VP latex were changed as described in Table 1. As the VP latex, a vinyl pyridine / styrene / butadiene terpolymer latex "Piratex FS" manufactured by Sumika ABS Latex Co., Ltd. is used. The symbol CN in Table 1 represents an orthocresol novolak type polyepoxide, and the polyepoxide described in Example 1 was used.
GE represents chrysidyl ether type polyepoxide, and uses "Denacol EX313" manufactured by Nagase Kasei Kogyo Co., Ltd. Table 1 also shows the characteristic evaluation results of the processing codes thus obtained. As is evident from the above results, the rubber hose reinforcing fiber obtained by the production method of the present invention exhibits better adhesiveness to EPDM as compared with the rubber hose reinforcing fiber obtained by the conventional formulation. be able to.

[0035]

As described above, according to the production method of the present invention, a rubber hose reinforcing fiber made of polyphenylene sulfide fiber having excellent adhesion to EPDM can be obtained.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 BB151 BC054 BQ004 CC054 CD063 CN012 FA042 FB082 GN00 4L033 AA06 AB01 AC11 CA13 CA34 CA49 CA68 CA70

Claims (6)

[Claims] 1. A polyphenylene sulfide fiber, which has been twisted not more than 200 times per meter, is treated with a first treating agent containing a cresol novolak type polyepoxide (A) and a rubber latex (B), and subsequently resorcinol / formaldehyde. A method for producing a rubber hose reinforcing fiber, characterized by treating with a second treating agent containing a mixture of an initial condensate (C) and a rubber latex (D). 2. The compounding ratio of the cresol novolak type polyepoxide (A) and the rubber latex (B) as the first treating agent is from 90:10 to 20:80 in terms of solids weight ratio. 2. The method for producing a rubber hose reinforcing fiber according to item 1. 3. The rubber latex (B) contained in the first treating agent is a rubber latex containing a vinylpyridine-styrene-butadiene terpolymer latex. A method for producing a rubber hose reinforcing fiber. 4. The method according to claim 1, wherein the first processing agent has a solid content of 0.5 to 3.0% by weight and the second processing agent has a solid content of 1.0 to 4.0% by weight. Claim 1.
4. The method for producing a rubber hose reinforcing fiber according to any one of claims 1 to 3. 5. After adhering the first treatment liquid to the fibers,
The fiber for reinforcing a rubber hose according to any one of claims 1 to 4, wherein the heat treatment is performed at a temperature of 200 to 260 ° C after a heat treatment is performed at a temperature of 200 to 260 ° C and a second processing liquid is subsequently applied. Manufacturing method. 6. The method for producing a rubber hose reinforcing fiber according to claim 1, wherein the rubber hose is a rubber hose comprising an ethylene / polypropylene / non-conjugated diene terpolymer rubber compound.