JP2014118664A - Polyphenylene sulfide fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide polyphenylene sulfide fiber whose adhesive properties with rubber is satisfactory and whose strength or the like are hard to be deteriorated, which could not have been achieved by the conventional technology from the problems, e.g., that the adhesive properties have been insufficient and its strength or the like have been made easy to be deteriorated.SOLUTION: The polyphenylene sulfide fiber is characterized in that the ratio of oxygen measured by XPS is 5 to 20% based on mol, and also, a C=O group is present, and it is preferable that the total of the ratio between a C=O peak and an O-C=O peak obtained by the peak resolution of C(1s) measured by XPS is 3 to 20%.

Description

  The present invention relates to polyphenylene sulfide fibers. Specifically, the present invention relates to polyphenylene sulfide fiber having good adhesion to rubber.

  Conventionally, polyphenylene sulfide is excellent in heat resistance, chemical resistance, oil resistance, and the like, and has been used as an engineering plastic that takes advantage of these characteristics. Moreover, it is known that polyphenylene sulfide can be easily made into a fiber by a melt spinning method similar to a general-purpose thermoplastic polymer, as described in Patent Document 1, for example. And the method of twisting a polyester fiber to a polyphenylene sulfide fiber, treating with a first treatment liquid containing a polyepoxide compound, and then treating with a second treatment liquid containing an RFL mixed solution is disclosed. (Patent Document 2).

  On the other hand, as an attempt to improve the adhesion of the synthetic fiber, the fiber is subjected to plasma treatment in an argon atmosphere under reduced pressure, and then reacted with a diene monomer and a monomer having a glycidyl group, and then treated with an RFL mixed solution. A technique is disclosed (Patent Document 3).

  In addition, a technique is disclosed in which a fiber is subjected to plasma treatment under reduced pressure in an atmosphere containing oxygen and carbon tetrachloride, and then treated with an RFL mixture (Patent Document 4). Patent Documents 3 and 4 also exemplify polyphenylene sulfide fibers as usable fibers, but do not disclose actually processed examples.

JP-A-49-54617 JP-A-11-279880 JP-A-63-223043 JP-A-4-249545

  Since the surface of the polyphenylene sulfide fiber is inactive, it has a problem of poor adhesion to rubber. Even if the methods of Patent Documents 3 and 4 are applied as they are in order to improve the adhesion of the polyphenylene sulfide fiber, there are problems that the adhesion is not always sufficient and the strength is easily deteriorated. It was.

  In view of the background of such prior art, the present invention is intended to provide polyphenylene sulfide fibers that have good adhesion to rubber and little strength reduction.

The present invention employs the following means in order to solve such problems.
(1) A polyphenylene sulfide fiber characterized in that the proportion of oxygen measured by XPS is 5 to 20% on a molar basis and a C═O group is present.
(2) The sum of the ratio of the C═O peak and the O—C═O peak obtained by peak splitting of C (1s) measured by XPS is 3 to 20% on the basis of the integrated value of the peak. The polyphenylene sulfide fiber according to claim 1.
(3) The polyphenylene sulfide fiber according to claim 1 or 2, which has been subjected to atmospheric pressure plasma treatment.
(4) The polyphenylene sulfide fiber according to any one of claims 1 to 3, which has been deoiled before atmospheric pressure plasma treatment.
(5) A polyphenylene sulfide fiber cord, wherein the polyphenylene sulfide fiber according to any one of claims 1 to 4 is subjected to RFL treatment.
(6) The polyphenylene sulfide fiber cord according to claim 5, wherein the use is a fiber for rubber reinforcement.

  That is, the present invention has sufficient adhesiveness to rubber, which cannot be achieved in the conventional polyphenylene sulfide fiber, by controlling the oxygen content within a limited range while containing a C═O group. It is possible to be satisfied.

  ADVANTAGE OF THE INVENTION According to this invention, the polyphenylene sulfide fiber with favorable adhesiveness with rubber | gum can be provided.

  The polyphenylene sulfide fiber of the present invention has been obtained as a result of intensive studies to create industrially practical cords for automobile hoses and belts. As a result, polyphenylene sulfide fibers having good adhesion to rubber have been obtained. It is.

  Hereinafter, the present invention will be described in detail.

  The polyphenylene sulfide fiber used in the present invention is not limited by the fineness, the number of filaments, the cross-sectional shape, etc., but usually the fineness is preferably 200 to 5000 dtex, particularly preferably 250 to 3000 dtex. As the number of filaments, 30 to 1000 filaments are preferable, and 50 to 500 filaments are particularly preferable. As the cross-sectional shape, a circular cross-sectional yarn is preferable.

  In the present invention, as a method for increasing the proportion of oxygen in the polyphenylene sulfide fiber, for example, the amount of oxygen in the polyphenylene sulfide fiber is increased by plasma treatment.

  The oxygen content of the polyphenylene sulfide fiber needs to be 5 to 20%, preferably 8 to 17% with respect to 100% of the total element amount on a molar basis when measured by XPS. If it is less than this range, the adhesive strength may be reduced, and if it is more than this range, the strength of the polyphenylene sulfide fiber may be reduced.

  Further, the polyphenylene sulfide fiber needs to have a C═O group. When it does not have a C═O group, the adhesive force may be reduced. Further, it preferably has an O—C═O bond.

  In the present invention, the sum of the ratio of the C═O peak and the O—C═O peak with respect to the C1s peak in the C1s peak division measured by XPS is the peak because the adhesive strength is particularly excellent and the strength reduction is particularly suppressed. The range is preferably 3 to 20%, more preferably 5 to 15%, based on the integral value.

  In plasma processing, it is convenient to use plasma generated by corona discharge, glow discharge, or a combination thereof.

  Plasma treatment includes vacuum low-pressure plasma, reduced-pressure oxygen plasma, etc., but the cost of reducing pressure / atmosphere replacement, etc., the effect of introducing chemical bonds such as C═O groups, and the damage on the fiber surface are small. A so-called atmospheric pressure plasma treatment performed at atmospheric pressure from a point or the like is preferable.

  In the plasma treatment, it is preferable to use mainly an inorganic gas as a carrier gas and a gas containing oxygen atoms as a reactive gas. Here, as the inorganic gas, nitrogen, argon, neon, hydrogen, oxygen, ammonia, carbon monoxide, carbon dioxide, or the like can be used, and a mixed gas thereof can also be used. The atmosphere can also be used because it contains oxygen as the reactive gas and nitrogen and carbon dioxide as the carrier gas. From the viewpoint of improving the efficiency of the plasma treatment, the gas used preferably does not contain moisture.

  In many cases, when forming polyphenylene sulfide fiber, an oil agent is attached for lubrication or convergence in the yarn forming process, but for the purpose of improving the effect of plasma treatment, trichlorethylene, hexane, methanol, acetone, etc. It is desirable to use after washing with an organic solvent or water and deoiling.

  The plasma-treated fiber obtained as described above is treated with a resorcin / formalin / rubber latex (RFL) mixed solution as described below. The treatment with the RFL mixed solution may be a treatment with a one-bath adhesion formulation using only the RFL mixed solution, but more preferably, after the treatment with the first adhesion treatment solution, the treatment with the second adhesion treatment solution containing the RFL mixture solution is performed. This is a treatment with a two-bath adhesive formulation.

  The first adhesive treatment liquid preferably contains a polyepoxide compound, but may contain a blocked isocyanate compound, an oxazoline group-containing compound, rubber latex, and the like.

  Examples of the polyepoxide compound used as a treating agent in the present invention include compounds containing 0.1 g equivalent or more per 100 g polyepoxide compound of at least two epoxy groups in one molecule. Specifically, reaction products of polyhydric alcohols such as pentaerythritol, ethylene glycol, polyethylene glycol, propylene glycol, glycerol, sorbitol and halogen-containing epoxides such as epichlorohydrin, unsaturated by peroxide or hydrogen peroxide, etc. Polyepoxide compound obtained by oxidizing compound, ie, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylene carboxylate, bis (3,4-epoxy-6-methyl-cyclohexylmethyl) adipate, phenol novolak type , Hydroquinone type, biphenyl type, bisphenol S type, brominated novolak type, xylene modified novolak type, phenol glyoxal type, trisoxyphenylmethane type, trisphenol PA type, biphenyl Aromatic polyepoxides such as phenolic polyepoxides, and the like.

  Blocked isocyanate compounds that can be used in the present invention include isocyanate compounds such as tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and triphenylmethane triisocyanate, and phenols such as phenol, cresol, and resorcin, ε -Lactams such as caprolactam and valerolactam, oximes such as acetoxime, methyl ethyl ketone oxime, cyclohexane oxime, and a reaction product with a blocking agent such as an ethyleneimine compound.

  The oxazoline group-containing compound that can be used in the present invention refers to a compound containing an oxazoline group (preferably a 2-oxazoline group) at the terminal or side chain of a substance having a main skeleton of a general organic compound, organic polymer, or oligomer. One or two or more oxazoline groups can be present in the skeleton, but it is more preferable to have many oxazoline groups that are reactive functional groups in order to improve adhesion performance. As the skeleton of the main chain of the oxazoline group-containing substance, hydrocarbon polymers, ethylene glycol chains, bisphenols such as bisphenol A, and initial polymers such as phenol resins, novolac resins, and resole resins are used. Also used are substances containing aromatic rings and heterocyclic rings. Furthermore, substances containing an oxazoline group at the terminal or side chain of the main component monomer and / or polymer or oligomer comprising the same are also useful. As these monomers, styrene, styrene derivatives, acrylonitrile, methacrylic acid esters, methacrylic acid, ethylene, butadiene, acrylamide, etc. are used, and these are used as a single polymer and / or oligomer and also as a copolymer. . It can also be used as a mixture thereof.

  The rubber latex is not particularly limited, but examples include natural rubber latex, styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, polybutadiene rubber latex, chloroprene rubber latex, vinylpyridine-styrene-butadiene rubber latex, ethylene-propylene. -Non-conjugated diene terpolymer rubber latex etc. are mentioned, These can be used individually or in mixture.

  The polyphenylene sulfide fiber of the present invention is preferably treated with a mixed solution containing RFL as the second treatment liquid after the plasma treatment or after the plasma treatment and after the first treatment liquid application and heat treatment.

  Here, RFL is a mixture of resorcin and formaldehyde initial condensate and rubber latex. The resorcin / formaldehyde initial condensate is a product obtained by condensing resorcin and formaldehyde in the presence of an alkali catalyst or an acid catalyst, and the molar ratio of resorcin to formaldehyde is 1 / 0.3 to 1/5. Is preferred. More preferably, it is the range of 1/1 to 1/3.

  Furthermore, as the resorcin / formaldehyde initial condensate, a novolak type resin obtained by reacting dihydroxybenzene and formaldehyde in advance in the absence of a catalyst or an acidic catalyst can also be used. When using a novolak resin of resorcin and formaldehyde, it is preferable to add formaldehyde after dissolution in an aqueous alkali catalyst dispersion to adjust the molar ratio of resorcin to formaldehyde to 1/1 to 1/3. The alkali catalyst used here is an alkali metal hydroxide, preferably sodium hydroxide. The concentration of the alkaline catalyst aqueous dispersion is preferably about 1 to 10 molar.

  The rubber latex used in resorcin / formalin / rubber latex is not particularly limited, but examples include natural rubber latex, styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, polybutadiene rubber latex, chloroprene rubber latex, vinylpyridine. -Styrene-butadiene rubber latex, ethylene-propylene-non-conjugated diene terpolymer rubber latex and the like can be mentioned, and these can be used alone or in combination.

  The ratio of resorcin / formalin / rubber latex resorcin / formalin and rubber latex is preferably resorcin / formalin / rubber latex = 1/3 to 1/15 in terms of solid content, more preferably 1/5. 1/12, more preferably 1/7 to 1/10. If the resorcin / formalin / rubber latex ratio is out of this range, the adhesiveness may be lowered or the process passability may be deteriorated. From the viewpoint of improving adhesiveness, the second treatment liquid of the present invention includes an adhesion aid, a filler, a crosslinking agent, an additive such as isocyanate, blocked polyisocyanate, ethylene urea compound, halogenated phenol derivative, and carbon black. A sulfurizing agent, a vulcanization accelerator, etc. may be mixed. These mixtures are preferably mixed in a range where the total does not exceed 50% by weight with respect to 100% by weight of the total solid content of the second treatment liquid. If it exceeds 50% by weight, the adhesive strength may decrease, the process passability may deteriorate, or the cord may become hard.

  Next, the outline of the method for producing the polyphenylene sulfide fiber of the present invention will be described.

  Polyphenylene sulfide fiber is twisted to form an untreated cord. Here, the twist form can be applied by either single twist or various twists. When performing deoiling treatment, it may be before twisting or after twisting, but it is preferable to perform deoiling treatment after twisting from the viewpoint of process passability during twisting.

  Next, the unprocessed code is subjected to plasma processing. Conditions such as the time for plasma treatment and the distance to the sample vary depending on the output of the equipment used, the efficiency of the treatment, and the like, and therefore may be adjusted so that the desired oxygen content is obtained. When the output and efficiency are high, it is desirable to set the processing time short or set the distance to the sample long. If the effect of the plasma treatment is too low, the adhesiveness is lowered, and if it is too high, the strength of the polyphenylene sulfide fiber may be lowered.

  Next, the polyphenylene sulfide fiber thus obtained can be made into a cord by performing the aforementioned RFL treatment. As described above, it is preferable to apply the first treatment liquid and the second treatment liquid.

  In order to adhere the treatment liquid used in the present invention to the polyphenylene sulfide fiber, any method such as dipping, nozzle spraying, and application by a roller can be employed. For example, it can be processed using a Rituler computer treater or a multi-cylinder type code setter.

  The adhesion amount of the first treatment agent and the second treatment agent to the polyphenylene sulfide fiber is preferably 0.5 to 8% by weight, particularly 3 to 5% by weight relative to the dry weight. The process passability is improved while maintaining the adhesiveness. The amount of adhesion can be controlled, for example, by setting the adhesive concentration and the liquid removal conditions after immersion in the adhesive liquid. Even when only the RFL process is performed, it is preferable to perform the adhesion amount.

  The heat treatment after applying the first treatment agent and the second treatment agent to the polyphenylene sulfide fiber is each dried at 80 to 180 ° C. for 0.5 to 5 minutes, more preferably 1 to 3 minutes, and then 150 to 280 ° C., More preferably, the heat treatment is performed at a temperature of 200 ° C. to 250 ° C. for 0.5 to 5.0 minutes, more preferably 1 to 3 minutes. If the heat treatment temperature is too low, adhesion to rubber will be insufficient, while if the heat treatment temperature is too high, the polyphenylene sulfide fiber will be melted, fused, hardened, and further deteriorated in strength. Disappear.

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

  Moreover, the evaluation method of polyphenylene sulfide fiber in the present invention is as follows.

(1) Oxygen content in XPS and C (1s) peak split value in XPS Measured by X-ray photoelectron spectroscopy. The conditions are as follows.
Apparatus: ESCALAB220iXL (Thermo Fisher Scientific Co., Ltd.)
Excitation X-ray: monochromic Al Kα _1.2 line (1486.6 eV)
X-ray diameter: 1mm
Photoelectron escape angle: 90 °
Smoothing: C1s main peak set to 284.6 eV

  The elemental composition was calculated from the area ratio of each peak by setting a baseline for each peak. The presence of the C═O group was confirmed by a peak of 287.6 eV ± 0.1 eV after the smoothing treatment. Further, the C1s peak was divided by a least square method using a symmetrical peak, and the ratio of each peak was calculated from the peak area ratio. The O—C═O peak was 288.6 eV ± 0.1 eV.

(2) Cord peeling adhesive strength The cord was wound around an aluminum plate so that there was no gap, EPDM rubber having the composition shown in Table 1 was attached to both sides of the aluminum plate, and press vulcanized at 150 ° C for 30 minutes. At this time, the thickness of the rubber was 3 mm, and the pressing pressure was adjusted so that the surface pressure of the rubber and the fiber cord was 3 MPa. The size of the aluminum plate and the area around which the fiber cord is wound may be arbitrary, and the tension at the time of winding is 0.5 cN / dtex. After standing to cool, the rubber side sample to which the cord was bonded was taken from the aluminum plate, and the sample was further cut into a width of 20 mm. While maintaining this sample at a temperature of 20 ° C. and a humidity of 65% at a speed of 50 mm / min and keeping the rubber and the fiber cord at an angle of 90 °, the peeling force when peeling the fiber cord from the rubber is N. Displayed at / 20 mm. The n number was 4.

(3) Amount of treatment agent adhesion Measured by b) mass method of JIS L1017 (2002) 8.15 dip pickup.

(4) Strength / strength retention rate JIS L1017 (2002) 8.5a) According to the standard time test, the sample was “TENSILON” UTM-100 manufactured by Orientec Co., Ltd., the grip interval was 25 cm, and the pulling speed was 30 cm / Went in minutes. The strength retention was calculated from the following formula.
Strength retention (%) = T1 / T0 × 100
T0: Tensile strength of cord not treated with plasma T1: Tensile strength of cord treated with plasma.

Example 1
(A) “Denacol” EX614B (manufactured by Nagase Kasei Co., Ltd.) as a polyepoxide compound, (B) “Nippol 2518FS” (manufactured by Nippon Zeon Co., Ltd., vinylpyridine / styrene / butadiene rubber latex), (C) blocked polyisocyanate A first treating agent having a solid content concentration of 5% by weight was prepared by mixing “Elastoron” BN27 (Daiichi Kogyo Seiyaku Co., Ltd.) as a compound in a solid content ratio of A: B: C = 1: 3: 1.

  Next, the second treating agent was prepared by the following method.

  Resorcin (R) is added to an aqueous caustic soda solution and sufficiently stirred and dispersed. To this, formalin (F) was added so that the R / F ratio was 1 / 1.5 (molar ratio), mixed uniformly, and aged at 25 ° C. for 4 hours. Next, “Nippol 2518FS” (manufactured by Nippon Zeon Co., Ltd., vinylpyridine / styrene / butadiene rubber latex) and “Nippol LX-111A” (manufactured by Nippon Zeon Co., Ltd., polybutadiene rubber latex) are mixed (vinylpyridine). -Styrene-butadiene rubber latex / polybutadiene rubber latex = 50/50 (weight ratio)) and the resorcin / formalin initial condensate dispersion in a solid content ratio (RF / L ratio) of 1/9, Aging was carried out at a temperature of 25 ° C. for 24 hours. Furthermore, “Denabond E” (manufactured by Nagase Kasei Kogyo Co., Ltd., 20% solution of chloro-modified resorcinol compound) was added so that the ratio of RFL and solid content (RFL / “Denabond”) was 4/1, and stirred sufficiently. Aged at 25 ° C. for 20 hours. The final treatment solution concentration was 13%.

  On the other hand, in the yarn production step, four multifilaments of polyphenylene sulfide fiber (Toray Industries, Inc., Torcon (440dTex)) were subjected to a single twist of 8 t / 10 cm to obtain an untreated cord.

  The untreated cord was washed with a shaker using trichloroethylene at 25 ° C. and deoiled. After drying, plasma treatment was carried out for 10 seconds using an ultra-high-density atmospheric pressure plasma treatment machine (Fuji Machine Manufacturing Co., Ltd., Tow Plasma FPC20). Nitrogen gas was used as the carrier gas, and air was used as the reactive gas. The respective flow rates were nitrogen: 4.98 l / min and air: 20 ml / min. The distance between the nozzle tip of the plasma processing machine and the cord was 3 mm.

  The plasma treatment code thus obtained was measured for oxygen content and C (1s) peak split value as described above. The results are shown in Table 1. Furthermore, after the plasma treatment code was immersed in the first treatment agent using a computer treater (CA Ritzler, Inc.), heat treatment was performed at 240 ° C. for 1 minute. Subsequently, after immersing in the second treatment agent, drying was performed at 120 ° C. for 1 minute, followed by heat treatment at 240 ° C. for 1 minute, and further heat treatment was performed at 240 ° C. for 1 minute.

  The cord thus obtained was measured for cord peeling adhesive strength and strength / elongation as described above. The results are shown in Table 1.

(Examples 2-5, Comparative Examples 1-4)
In Example 1, the treatment was performed under the same conditions as in Example 1 except that the plasma treatment time was changed, and thereby the oxygen content was changed. The evaluation results are also shown in Table 1.

  As can be seen from the evaluation results shown in Table 1, it can be seen that the polyphenylene sulfide fiber according to the present invention is excellent in adhesiveness to rubber.

Claims (6)

A polyphenylene sulfide fiber characterized in that the proportion of oxygen measured by XPS is 5 to 20% on a molar basis and a C═O group is present. The sum of the ratio of C = O peak and O-C = O peak obtained by peak splitting of C (1s) measured by XPS is 3 to 20% on the basis of the integrated value of the peak. The polyphenylene sulfide fiber according to 1. The polyphenylene sulfide fiber according to claim 1 or 2, which has been subjected to an atmospheric pressure plasma treatment. The polyphenylene sulfide fiber according to claim 3, which has been deoiled before atmospheric pressure plasma treatment.   A polyphenylene sulfide fiber cord obtained by performing RFL treatment on the polyphenylene sulfide fiber according to claim 1.   The polyphenylene sulfide fiber cord according to claim 5, wherein the use is a rubber reinforcing fiber.