JP2007071228A - Transmission belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission belt capable of improving adhesive property and resistance to tearing-up and having excellent durability. <P>SOLUTION: This toothed belt 1 has a belt main body composed of a plurality of tooth parts 2 along the longitudinal direction of the belt and a back part 4 burying a core wire 3, and tooth cloth 5 is stuck to a surface of the tooth part 2 as required. Here, the tooth parts 2 and the back part 4 are constituted by an organic peroxide cross linking substance of a rubber composition prepared by blending silica of 5 to 60 pts.wt., polyparaphenylene-benzobisoxazole short fibers of 1 to 40 pts.wt., and ester methacrylate and/or acrylic ester of 0.1 to 10 pts.wt. into a rubber component containing hydrogenated nitrile rubber of 100 pts.wt. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power transmission belt used for power transmission of a drive device or the like.

  In recent years, the quality required for transmission belts has become stricter year by year. In particular, power transmission belts used in automobile engines must be able to withstand the temperature in the engine room, which was originally harsh as the environmental temperature, but the temperature in the engine room tends to rise further. The transmission belt is also required to withstand extremely high temperatures. In addition, as the space is saved and the engine is made more compact, the engine room has become considerably narrower, and there is a demand for a narrower belt.

In response to the demand for improvement in heat resistance, it has been proposed to use a hydrogenated nitrile rubber crosslinked with an organic peroxide as a rubber composition constituting the tooth rubber and back rubber of a toothed belt. (For example, see Patent Document 1) And for the demand for narrowing, the rubber physical properties are improved by increasing the amount of reinforcing materials such as carbon black and short fibers, organic peroxides, vulcanization accelerators and co-crosslinking agents. Consideration has been made to cope with the narrowing.
JP-A-64-87937

  However, when a rubber composition in which a reinforcing material is highly filled is used for a transmission belt that repeatedly receives compressive force, large agglomerates of the reinforcing material are generated, resulting in reinforcement, wear resistance, tensile strength, and hysteresis. In addition, it was inferior in bending fatigue and caused an early belt life. In addition, since it is inferior in adhesion to the fiber cord serving as the core wire, there is a problem in that it does not form a good composite and the belt life is shortened.

  The present invention solves such problems, and an object of the present invention is to provide a transmission belt that has improved tear resistance and adhesion, and has high durability even under high load use.

  In the invention according to claim 1, at least a part of the main body has 5 to 60 parts by weight of silica and 1 polyparaphenylenebenzobisoxazole short fiber with respect to 100 parts by weight of the rubber component containing hydrogenated nitrile rubber. A transmission belt comprising an organic peroxide-based cross-linked product of a rubber composition containing -40 parts by weight and 0.1-10 parts by weight of methacrylic acid ester and / or acrylic acid ester.

  The invention according to claim 2 of the present application is the power transmission belt according to claim 1, wherein the rubber component is (b) a composite polymer in which a hydrogenated nitrile rubber and an unsaturated carboxylic acid metal salt are blended, and (b) hydrogen. It is characterized by containing a nitrile rubber.

  The invention according to claim 3 of the present application is the transmission belt according to claim 2, wherein the rubber component is (i) a hydrogenated nitrile rubber and an unsaturated carboxylic acid metal salt in a weight ratio of 30:70 to 70:30. The blended composite polymer and (b) hydrogenated nitrile rubber are blended so that the weight ratio is 10:90 to 70:30.

  Invention of Claim 4 of this application is a power transmission belt of any one of Claims 1-3, Comprising: Methacrylic acid ester and / or acrylic acid ester are trimethylol propane trimethacrylate, It is characterized by the above-mentioned. To do.

  The invention according to claim 5 of the present application is the transmission belt according to any one of claims 1 to 4, wherein the transmission belt is a toothed belt.

  The invention according to claim 6 of the present application is the transmission belt according to any one of claims 1 to 4, wherein the transmission belt is a cogged V-belt.

  In the present invention, by constituting a part of the main body with a specific rubber composition, a transmission belt having improved durability and tear resistance and adhesion can be obtained. Further, by making the rubber component a blend of a composite polymer and hydrogenated nitrile rubber, various physical properties such as tensile modulus, hardness, cutting elongation, and tear strength can be enhanced. Furthermore, by setting the blend ratio within a specific range, it is possible to ensure tensile modulus, cut elongation, higher tear strength, hardness, and the like.

  And by selecting a specific compound as a methacrylic acid ester and / or an acrylic acid ester, it is possible to obtain a high modulus structure with excellent tear resistance. Further, when the present invention is applied to a toothed belt, it is excellent in tooth chip resistance and adhesiveness with a core wire, and the life of the belt can be extended. Furthermore, when applied to a cogged V-belt, it has excellent lateral pressure resistance and wear resistance, and can suppress cracks in the cog valley.

  In the power transmission belt of the present invention, at least a part of the main body is 5 to 60 parts by weight of silica and 1 to 40 polyparaphenylene benzobisoxazole short fibers with respect to 100 parts by weight of the rubber component containing hydrogenated nitrile rubber. It is characterized by comprising an organic peroxide-based cross-linked product of a rubber composition containing 0.1 part by weight and 0.1 to 10 parts by weight of methacrylic acid ester and / or acrylic acid ester.

  The hydrogenated nitrile rubber (H-NBR) used in the present invention has an acrylonitrile bond amount of 10 to 40% by weight composed of an unsaturated nitrile such as acrylonitrile or methacrylonitrile, and 1,3-butadiene or 2,3-dimethylbutadiene. , Copolymers of 90 to 60% by weight of conjugated dienes such as isoprene and 1,3-pentadiene, and multi-component copolymers obtained by copolymerizing a copolymerizable ethylenically unsaturated monomer in addition to these monomers Is mentioned. If the amount of the unsaturated nitrile in the nitrile rubber is too small, the hardness, modulus and oil resistance will be lowered and the function as a transmission belt will not be satisfied, and conversely if too much, the cold resistance will be lowered and the hardness and modulus will be reduced. However, there are problems such as inferior general physical properties.

  Examples of the ethylenically unsaturated monomer include vinyl aromatic compounds such as styrene, chloromethyl styrene, and α-methyl styrene, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, ethoxyethyl acrylate, maleic acid , Unsaturated dicarboxylic acids such as itaconic acid, monomethylmaleic acid ester and dimethylmaleic acid ester, and monoesters and diesters of these unsaturated dicarboxylic acids.

  H-NBR can be used alone, but for example, it is possible to use (B) a composite polymer containing H-NBR and an unsaturated carboxylic acid metal salt and (B) H-NBR. It is preferable for improving various physical properties such as tensile elastic modulus, hardness, elongation at break, and tear strength. By comprising in this way, it is thought that unsaturated carboxylic acid metal salt makes a polymer part high order structure, and it forms the filler which unsaturated carboxylic acid metal salt disperse | distributed finely by polymer part, and H-NBR whole quantity from the beginning It can have a higher tensile strength than blending an unsaturated carboxylic acid metal salt in the minute.

  More preferably, the rubber component comprises (b) a composite polymer obtained by blending H-NBR and an unsaturated carboxylic acid metal salt in a weight ratio of 30:70 to 70:30 and (b) H-NBR in a weight ratio of 10. : It is preferable to use a rubber component blended at 90 to 30:70 in order to ensure tensile elastic modulus, cut elongation, higher tear strength, hardness, and the like.

  The unsaturated carboxylic acid metal salt is an ionic bond of an unsaturated carboxylic acid having a carboxyl group and a metal. Examples of the unsaturated carboxylic acid include monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid, fumaric acid, Dicarboxylic acids such as itaconic acid are preferred, and the metals are beryllium, magnesium, calcium, strontium, barium, titanium, chromium, molybdenum, manganese, iron, cobalt, nickel, copper, silver, zinc, cadmium, aluminum, tin, lead, Antimony or the like can be preferably used.

  Silica is not limited to dry silica or wet silica. The amount of silica is 5 to 60 parts by weight with respect to 100 parts by weight of the rubber component containing H-NBR. Since Shirika has a high cohesive force, a rubber composition having a higher modulus than that of a carbon black compounding system can be obtained. When the blending amount is less than 5 parts by weight, the modulus and strength are low. On the other hand, when it exceeds 60 parts by weight, there is a problem in the flexibility of the belt because the adhesive strength is lowered and the rigidity of the rubber is increased.

  Furthermore, the rubber composition contains 0.1 to 10 parts by weight of methacrylic acid ester and / or acrylic acid ester with respect to 100 parts by weight of rubber. Methacrylic acid ester and / or acrylic acid ester acts as a co-crosslinking agent in organic peroxide crosslinking, and can improve tear resistance and reduce unvulcanized viscosity. That is, when PBO short fibers and silica are blended with rubber, the viscosity increases and processability decreases, and there is a risk of causing a tooth shape defect in a toothed belt and a cog shape defect in a cogged V belt. And / or by mix | blending a specific amount of acrylic acid ester, the raise of an unvulcanized viscosity is suppressed and workability is not impaired. If the amount is less than 0.1 part by weight, the effect of addition is not remarkable, and if it exceeds 10 parts by weight, the tearing force and the adhesive force are rapidly reduced.

  Specific examples of the methacrylic acid ester and / or acrylic acid ester include ethylene dimethacrylate, polyethylene glycol dimethacrylate, propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, tripropylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetra Examples thereof include methacrylates and acrylates corresponding to these. These can be used alone or in admixture of two or more. Of these, trimethylolpropane trimethacrylate (TMPT) is preferable.

  And 1-40 weight part of polyparaphenylene benzobisoxazole short fiber (PBO short fiber) is mix | blended with the said rubber composition with respect to 100 weight part of rubber | gum. PBO short fibers having a fiber length of 1 to 20 mm and a fiber diameter of 1 to 3 denier are preferably used.

  In addition, it is not essential to add the PBO short fiber alone, and it is also possible to add short fibers made of other materials. Examples of short fibers that can be blended in addition to PBO short fibers include short fibers such as aramid fibers, polyamide fibers, polyester fibers, and cotton. The fiber length varies depending on the fiber type, but a short fiber of 1 to 10 mm is suitable. Specifically, an aramid fiber having a length of 3 to 5 mm, a polyamide fiber, a polyester fiber or cotton having a length of 5 to 10 mm can be used. . Among these, it is preferable to select an aramid fiber in consideration of wear resistance, reinforcement, and the like. Aramid short fibers are, for example, trade names Conex, Nomex, Kevlar, Technora, Twaron and the like.

  In addition, since it is difficult to adhere | attach PBO fiber with rubber | gum compared with another fiber, it is desirable to give an adhesion | attachment process. As the adhesion treatment, a known treatment method can be applied. For example, there is a method of treating with a resorcin / formaldehyde / latex (RFL) solution after treatment with an adhesion treatment solution containing a nitrile rubber-modified epoxy resin and an alkylphenol / formaldehyde resin. The aramid short fibers are also preferably subjected to adhesion treatment by a known method using an RFL solution or the like.

  The RFL liquid used here is a treatment liquid in which a resorcin / formaldehyde initial condensate and a rubber latex are mixed. In this case, the molar ratio of resorcin to formaldehyde is preferably 3/1 to 1/3 in order to increase the adhesive force. Moreover, it is preferable when the solid content adhesion amount of RFL liquid is 3-10 weight%, when raising the effect of the adhesive force by RFL liquid. If it exceeds 1/1, the cohesive force of the short fibers becomes large and the dispersibility becomes worse. Conversely, if it becomes less than 1/5, the adhesive strength between the rubber and the short fibers may decrease, and the tensile strength may also decrease. is there. Further, when the solid content adhesion amount of the RFL liquid exceeds 10% by weight, the treatment liquid is hardened and it becomes difficult to split filaments of short fibers. Conversely, when the amount is less than 3% by weight, the dispersibility and tension by the RFL liquid are reduced. Strength improvement effect is not remarkable. Examples of rubber latex include styrene / butadiene / vinylpyridine terpolymer, chlorosulfonated polyethylene, hydrogenated nitrile rubber, epichlorohydrin, natural rubber, SBR, chloroprene rubber, olefin-vinyl ester copolymer, EPDM, and the like. Latex. In addition, the temperature of the process liquid at the time of performing an adhesion process is adjusted to 5 to 40 ° C., and the immersion time is 0.5 to 30 seconds, and it is passed through an oven adjusted to 200 to 250 ° C. for 1 to 3 minutes. It is desirable to be heat treated. In addition, a pre-dip process can be performed before the RFL process, or an overcoat process can be performed after the RFL process.

  The rubber composition is blended with an organic peroxide as a crosslinking agent. Examples of the organic peroxide include dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, 1,3-bis (t-butylperoxyisopropyl) benzene, 2,5 -Dimethyl-2,5-di (t-butylperoxy) hexyne-3,2,5-dimethyl-2,5- (benzoylperoxy) hexane, 2,5-dimethyl-2,5-mono (t- Butyl peroxy) hexane and the like. This organic peroxide is 1-8 weight part with respect to 100 weight part of rubber components individually or as a mixture, More preferably, it is 1.5-4 weight part.

  The rubber composition can be added to a normal rubber compound such as an enhancer such as carbon black, a filler such as calcium carbonate or talc, a plasticizer, a stabilizer, a processing aid, or a colorant as necessary. What is used can be mix | blended.

  As an example of the transmission belt according to the present invention, a mesh transmission belt and a friction transmission belt are illustrated. Specifically, a sectional perspective view of the toothed belt 1 is shown in FIG. 1, and a sectional perspective view of the cogged V belt 10 is shown. 2 is shown.

  The toothed belt 1 in FIG. 1 has a belt body composed of a plurality of tooth portions 2 and a back portion 4 in which a core wire 3 is embedded along the belt longitudinal direction (arrow in the figure). A tooth cloth 5 is attached to the surface as necessary.

  In addition, when the toothed belt 1 is produced by the press-fitting molding method, the tooth portion 2 and the back portion 4 are formed from the same rubber composition sheet, so that the back portion 4 also has the same rubber layer as the tooth portion 2.

  The cogged V-belt 10 in FIG. 2 has a configuration in which an inner peripheral compression portion 12, an outer peripheral extension portion 5, and an adhesive portion 18 are laminated between the rubber layers 12 and 15. Is embedded with a core wire 19 extending in the belt longitudinal direction. Further, the compression section 12 and the expansion section 15 are alternately formed with cog mountains 13 and 16 and cog valleys 14 and 17 extending in the belt width direction along the belt longitudinal direction.

  The core wires 3, 19 used in the present invention are, for example, polyarylate fiber, polybutylene terephthalate (PBT) fiber, polyethylene terephthalate (PET) fiber, polytrimethylene terephthalate (PTT) fiber, polyethylene naphthalate (PEN) fiber, etc. Cords such as polyester fiber, aramid fiber, glass fiber, and carbon fiber can be used. The composition of the glass fiber may be either E glass or S glass (high-strength glass), and is not limited to the thickness of the filament, the number of converging filaments, and the number of strands.

  The cores 3 and 19 are preferably subjected to an adhesion treatment to improve the adhesion to rubber. For example, (1) after impregnating the untreated cord into a tank containing a pretreatment liquid containing an epoxy compound, an isocyanate compound or the like and pre-dipping, (2) in a drying furnace set at a temperature of 160 to 200 ° C. (3) Subsequent immersion in a tank containing an RFL solution and (4) Pass through a stretching heat setting processor set at 210 to 350 ° C. for 30 to 600 seconds. -1 to 3% stretched to obtain a stretched cord, (5) immersed in a tank containing rubber paste, and (6) dried for 120 to 300 seconds through a drying oven set at 130 to 170 ° C. There are methods. Note that it is not necessary to perform all the steps (1) to (6), and it is also possible to perform only (1) to (4) as desired.

  Examples of the isocyanate compound used in this pretreatment liquid include 4,4′-diphenylmethane diisocyanate, tolylene 2,4-diisocyanate, polymethylene polyphenyl diisocyanate, hexamethylene diisocyanate, and polyaryl polyisocyanate (for example, PAPI as a trade name) ) Etc. This isocyanate compound is used by mixing with an organic solvent such as toluene or methyl ethyl ketone.

  In addition, blocked polyisocyanates in which the isocyanate group of the polyisocyanate is blocked by reacting the isocyanate compound with a blocking agent such as phenols, tertiary alcohols, and secondary alcohols can also be used.

  Examples of the epoxy compound include reaction products of polyhydric alcohols such as ethylene glycol, glycerin and pentaerythritol, polyalkylene glycols such as polyethylene glycol and halogen-containing epoxy compounds such as epichlorohydrin, resorcin, bis (4-hydroxy Phenyl) dimethylmethane, phenol. Formaldehyde resin, resorcin. Reaction products with polyhydric phenols such as formaldehyde resins and halogen-containing epoxy compounds. The epoxy compound is used by mixing with an organic solvent such as toluene or methyl ethyl ketone.

  The RFL treatment liquid is a mixture of resorcin and formaldehyde precondensate with rubber latex. In this case, the molar ratio of resorcin and formaldehyde is preferably 1: 2 to 2: 1 in order to increase the adhesive force. . If the molar ratio is less than 1/2, the three-dimensional reaction of resorcin-formaldehyde resin proceeds too much and gels, while if it exceeds 2/1, the reaction between resorcin and formaldehyde does not progress so much, resulting in a decrease in adhesive strength. To do. Examples of the rubber latex include styrene / butadiene / vinylpyridine terpolymer, H-NBR, chloroprene rubber, and nitrile rubber.

  The weight ratio of the solid content of the resorcin-formaldehyde initial condensate and the rubber latex is preferably 1: 2 to 1: 8. Maintaining this range is suitable for increasing the adhesive strength. When the above ratio is less than 1/2, the resin content of resorcin-formaldehyde increases, the RFL film becomes hard and dynamic adhesion deteriorates. On the other hand, when the ratio exceeds 1/8, the resin content of resorcin-formaldehyde Therefore, the RFL film becomes soft and the adhesive strength decreases.

  Furthermore, a crosslinking accelerator or a crosslinking agent may be added to the RFL solution, and the crosslinking accelerator to be added is a sulfur-containing crosslinking accelerator, specifically 2-mercaptobenzothiazole (M) or a salt thereof. (For example, zinc salt, sodium salt, cyclohexylamine salt, etc.) Thiazoles such as dibenzothiazyl disulfide (DM), sulfenamides such as N-cyclohexyl-2-benzothiazylsulfenamide (CZ), tetramethyl Thiurams such as thiuram monosulfide (TS), tetramethylthiuram disulfide (TT), dipentamethylene thiuram tetrasulfide (TRA), sodium di-n-butyldithiocarbamate (TP), zinc dimethyldithiocarbamate (PZ) diethyldimethyl Dithiocarbamine such as zinc dithiocarbamate (EZ) There are salts and the like. Moreover, as a crosslinking agent, there exist sulfur, a metal oxide (zinc oxide, magnesium oxide, lead oxide), a peroxide, etc., and it uses together with the said crosslinking accelerator.

  In the present invention, at least a part of the main body is composed of the organic peroxide-based crosslinked product of the rubber composition, preferably the transmission part is the organic peroxide-based crosslinked product. It is desirable to form. Needless to say, all the rubber constituting the transmission belt body can be composed of the organic peroxide-based crosslinked product.

  In the toothed belt 1 shown in FIG. 1, the rubber layer serving as the transmission portion is the tooth portion 2, but the back portion 4 can also be composed of the rubber composition.

  In the cogged V-belt 10 shown in FIG. 2, the rubber layer serving as the transmission portion is the compression portion 12, but the extension portion 15 and the adhesion portion 18 can also be formed of the rubber composition.

  When a rubber composition other than the above rubber composition is used for the belt body, for example, a blend rubber obtained by mixing H-NBR alone or a partner rubber made of other kinds of rubber as a rubber component may be used. The partner rubber blended with H-NBR is ethylene / α-olefin elastomer, butadiene rubber (BR), styrene / butadiene rubber (SBR), nitrile rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), natural Mention may be made of rubber (NR).

  As the tooth cloth 5 that covers the tooth surface of the toothed belt 1, a canvas made of a plain woven fabric, a twill woven fabric, a satin woven fabric, or the like is used. As the wefts arranged in the belt longitudinal direction of these woven fabrics, for example, multifilament yarns obtained by converging filament base yarns of para-aramid fibers of 0.3 to 1.2 deniers are 20 to 80 of the total amount of wefts in the belt longitudinal direction. Those containing wt% are preferred.

  That is, the weft is a yarn including a multi-filament yarn of para-aramid fiber, and the multi-filament yarn of the para-aramid fiber can include a yarn made of a meta-aramid fiber. The specific configuration of the weft is a combination of three types of yarns, a multi-filament yarn of para-aramid fiber, a spun yarn made of meta-aramid fiber, and a urethane elastic yarn.

  Other specific wefts are composed of three types of yarns: multi-filament yarns of para-aramid fibers, aliphatic fiber yarns (6 nylon, 66 nylon, polyester, polyvinyl alcohol, etc.), and urethane elastic yarns. It may be twisted.

  The warp of the tooth cloth 5 is composed of filament yarns of aramid fibers made of para-type aramid fibers and meta-type aramid fibers, polyamide yarns such as 6 nylon, 6.6 nylon and 12 nylon, and filament yarns of polyvinyl alcohol and polyester. Preferably, if the filament yarn of aramid fiber is a multifilament yarn in which the filament yarn of para-aramid fiber is converged for the weft yarn 5, the rigidity balance is achieved and the tooth cloth becomes uniform in thickness.

  However, the materials of the warp and weft are not limited to these, and other forms include cords, non-woven fabrics, knitted fabrics and the like, and are not particularly limited. In addition, it is desirable that the tooth cloth is adhered with an adhesive rubber by soaking, spreading, coating, or the like.

  Further, the cogged V-belt 10 can be laminated with a reinforcing cloth on the surface of the compression part 12 or the surface of the extension part 15 as necessary. Examples of the reinforcing fabric include canvas selected from woven fabrics, knitted fabrics, nonwoven fabrics, and the like. Known and publicly used fiber materials can be used. For example, natural fibers such as cotton and hemp, inorganic fibers such as metal fibers and glass fibers, and polyamide, polyester, polyethylene, polyurethane, polystyrene, and polyfluoroethylene. , Organic fibers such as polyacryl, polyvinyl alcohol, wholly aromatic polyester, and aramid. The canvas can be immersed in an RFL solution and then rubbed with an unvulcanized rubber after immersion in a known technique, or can be immersed in a soaking solution in which the rubber is dissolved in a solvent after being immersed in the RFL solution. The RFL solution may be appropriately mixed with a carbon black solution to blacken the treatment, or a known surfactant may be added in an amount of 0.1 to 5.0% by weight.

  The transmission belt is not limited to the above-described toothed belt and cogged V belt, and a V-ribbed belt and a flat belt also belong to the technical scope of the present invention. Further, the cogged V-belt is not limited to the above-described configuration, and a cogged V-belt provided with a cog only in one of the compression unit and the expansion unit can also be exemplified.

  As a method for producing the rubber composition used in the present invention, first, as a masterbatch kneading in the first step, H-NBR, short fibers and a softening agent are put into a closed kneader such as a Banbury mixer and kneaded. The kneaded master batch is discharged once and cooled to 20 to 50 ° C. This is to prevent rubber scorching. Next, a predetermined amount of reinforcing agent, filler, anti-aging agent, vulcanization accelerator, vulcanizing agent, and the like are finished and kneaded into the obtained master batch using a Banbury mixer and an open roll. Further, depending on the type of rubber, it is not necessary to once discharge the kneaded master batch and cool it down, and it is possible to carry out finish kneading continuously.

  The kneading method is not limited to the above method, and the kneading means is not limited to, for example, a Banbury mixer, a roll, a kneader, and an extruder, and may be kneaded appropriately by known means and methods. it can. Further, the vulcanization method is not limited, and vulcanization is performed by a known means using a vulcanization apparatus such as mold heating, hot air heating, a rotating drum vulcanizer, an injection molding machine or the like.

Hereinafter, a description will be given with specific examples.
The Mooney viscosity (125 ° C.) of the rubber composition prepared by blending shown in Table 1 was measured according to JIS K6300-1. In addition, the PBO short fiber used what gave the adhesion process. Further, the rubber composition was vulcanized at 165 ° C. for 30 minutes, and the hardness (JIS-A) of the obtained vulcanized rubber (organic oxide-based crosslinked product) was JIS K6253, and tearing force (JIS-A: N). / Mm) was measured according to JIS K6252. Further, the glass fiber cords subjected to the adhesion treatment are arranged in a 25 mm width on a rubber sheet having a thickness of 4 mm having the composition shown in Table 1, and vulcanized at 165 ° C. for 30 minutes by applying a pressure of 2.0 MPa with a press plate. A sample for an adhesion test was prepared. The adhesion strength of each sample was measured according to JIS K6256. The measurement results are also shown in Table 1.

<Toothed belt>
Examples 1-3, 5-7, Comparative Examples 2, 3
A toothed belt was produced using a rubber sheet containing the rubber shown in Table 1. In the toothed belt produced in this example, the toothed belt has a tooth part covered with a nylon tooth cloth, and a glass core wire is embedded in the main body. The belt size is tooth type: MY, number of teeth: 105, Belt width: 60 mm in size.

  Here, the tooth part and the back part were prepared from the rubber composition shown in Table 1, kneaded with a Banbury mixer, and then rolled with a calender roll.

  A nylon tooth cloth was wound around a tooth-shaped mold for forming a belt, and then a glass core wire subjected to adhesion treatment was wound around a spiral with a predetermined tension at a predetermined pitch. After pasting the rubber sheet of Table 1 on this core, it is put into a cross-linking can and pressure-crosslinked at 165 ° C for 30 minutes by a normal press-fitting method, and the back surface of the belt is polished to a certain thickness. Then, it was cut into a certain width to obtain a toothed belt.

  The toothed belt thus obtained was subjected to a running test under a high load of 15 kgf per 1 mm width of the belt at an ambient temperature of 23 ° C. according to the layout shown in FIG. The results are also shown in Table 2.

<Cogged V Belt>
Example 4, Comparative Examples 1 and 4
A cut edge type cogged V-belt was prepared using a rubber sheet containing the rubber shown in Table 1. The cogd V-belt produced in this example has a compression part in which 1 ply canvas is laminated on the surface, an extension part in which 1 ply canvas is laminated on the surface, and a cord made of polyester fiber rope between both rubber layers. It has a configuration in which the bonded portion is arranged. Cogs are formed on the inner and outer peripheral surfaces of the belt. The compression part and the extension part contain short fibers and are oriented in the belt width direction.

  Here, the rubber sheet forming the stretched part and the compressed part was prepared with the rubber composition shown in Table 1, kneaded with a Banbury mixer, and then rolled with a calendar roll. Moreover, the rubber sheet which forms an adhesion part was adjusted by the rubber | gum compound which remove | excluded the short fiber from the rubber | gum compound shown in Table 1, knead | mixed with the Banbury mixer, and what was rolled with the calendar roll was used.

  The belt manufacturing method is a known method. First, a one-ply reinforcing cloth, an unvulcanized compressed rubber sheet, and an unvulcanized adhesive rubber sheet are wound around the circumferential surface of a cylindrical drum provided with grooves at predetermined intervals. After that, a core rope was spun into a spiral shape, and an unvulcanized stretched rubber sheet and a 1-ply reinforcing cloth were wound to obtain a laminate (unvulcanized belt sleeve). Sulfurize to obtain a vulcanized belt sleeve. The vulcanized belt sleeve thus obtained was cut into a predetermined width by a cutter and finished into individual cogged V-belts.

  The durability of the cogged V belt thus obtained was evaluated. In the belt endurance test, the belt is suspended on a two-axis horizontal running tester having the layout shown in FIG. 4, a load of 6.77 kw is applied to the driven pulley at an ambient temperature of 85 ° C., and the drive pulley is set to 7, The running life of the belt was measured by rotating at 000 rpm. The cut-off time was 240 hours, and when it reached the end of its life, the cause of the failure was confirmed. The results are also shown in Table 2.

  As a result, the belt of the example had high adhesiveness, improved tear resistance, high modulus, excellent durability, and a long running life. The toothed belt has a good tooth shape, and the cogged V belt has a good cog shape. However, in Comparative Example 1 in which silica was not blended, the hardness of the blended carbon black was not increased and the tearing force and adhesion were poor. Further, in the running test, there was a problem that a crack occurred in the compressed portion at an early stage of running and the belt life was extremely short. Further, in Comparative Example 2 in which silica is excessively blended, the adhesiveness is low and the composite of the core wire and the rubber is not good. Therefore, in the running test, a crack occurs at the boundary between the core wire and the rubber, and the life is shortened. became. In Comparative Example 3, a general-purpose TAIC was used as a co-crosslinking agent. However, the tear resistance was poor, and the tooth part was cracked and the life was reached. In Comparative Example 4 in which PBO short fibers were not blended and polyamide short fibers were blended, the strength was inferior and the belt life could not be said to be sufficient.

  The transmission belt according to the present invention can be attached to a drive device for automobiles or general industries.

It is a section perspective view of a toothed belt which is a power transmission belt concerning the present invention. It is a cross-sectional perspective view of the cogged V belt which is a power transmission belt which concerns on this invention. It is a figure which shows the layout of the testing machine used in the toothed belt durability test. It is a figure which shows the layout of the testing machine used in the cogged V belt durability test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Toothed belt 2 Tooth part 3 Core wire 4 Back part 5 Tooth cloth 10 Cogged V belt 12 Compression rubber layer 13,16 Cog mountain 14,17 Cog valley 15 Stretch rubber layer 18 Adhesive rubber layer 19 Core wire

Claims (6)

  At least a part of the main body is 5 to 60 parts by weight of silica, 1 to 40 parts by weight of polyparaphenylenebenzobisoxazole short fiber, and methacrylic acid ester with respect to 100 parts by weight of the rubber component containing hydrogenated nitrile rubber. A power transmission belt comprising an organic peroxide-based crosslinked product of a rubber composition containing 0.1 to 10 parts by weight of an acrylic ester.   2. The power transmission belt according to claim 1, wherein the rubber component is a mixture of (b) a hydrogenated nitrile rubber and (b) a hydrogenated nitrile rubber.   The rubber component is a composite polymer obtained by blending (i) hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt in a weight ratio of 30:70 to 70:30 and (b) hydrogenated nitrile rubber in a weight ratio of 10: The power transmission belt according to claim 2, wherein the power transmission belt is blended so as to be 90 to 70:30.   The transmission belt according to any one of claims 1 to 3, wherein the methacrylic acid ester and / or the acrylic acid ester is trimethylolpropane trimethacrylate.   The power transmission belt according to claim 1, wherein the power transmission belt is a toothed belt. The transmission belt according to any one of claims 1 to 4, wherein the transmission belt is a cogged V belt.

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