JP4624747B2 - Power transmission belt - Google Patents

Description

  The present invention relates to a power transmission belt used for power transmission.

  In belts used for power transmission, deterioration of rubber in an ozone atmosphere is regarded as a problem, and belts made of conventional natural rubber, styrene-butadiene rubber, chloroprene rubber, etc. crack early due to this rubber deterioration. Has been pointed out. Further, since rubber containing halogen such as chloroprene leads to generation of dioxins, a belt made of rubber not containing halogen which is an environmental load substance has been demanded in recent years.

Recently, ethylene / α-olefin rubber such as ethylene-propylene rubber (EPR) or ethylene-propylene-diene copolymer rubber (EPDM) has excellent ozone resistance, heat resistance, It is a promising polymer because it is cold resistant and relatively inexpensive, and satisfies the requirement of dehalogenation. (For example, see Patent Document 1)
JP-A-6-345948

  However, the adhesiveness of ethylene / α-olefin rubber including ethylene-propylene rubber is low, and it has been a problem particularly with respect to adhesiveness with fiber base materials such as a core wire. In addition, the tearing force is low in combination with the poor adhesion, and the use of a peroxide crosslinking system further reduces the tearing force, causing a problem that the core wire tends to pop out during running.

  The present invention solves such problems, and an object of the present invention is to provide a power transmission belt excellent in adhesion to a core wire and tear resistance.

The present invention is a power transmission belt in which a core wire is embedded along a longitudinal direction of the belt in a main body made of rubber, and at least a rubber layer in which the core wire is embedded has a vinyl ester content of 30 to 70 as a rubber component. 5% by weight of ethylene-vinyl ester copolymer and ethylene / α-olefin rubber in a weight ratio of 5/95 to 100/0, an organic peroxide is blended as a crosslinking agent, and 100 parts by weight of a rubber component A power transmission belt comprising a rubber composition containing 0.5 to 13 parts by weight of N, N′-m-phenylene dimaleimide and / or quinonedioxime.

The present invention, the ethylene as a rubber component - to 10 / 90-60 / 40 containing a vinyl ester copolymer and ethylene · alpha-olefin rubber in a weight ratio, ethylene - vinyl ester copolymer, ethylene - vinyl acetate It is a copolymer; an invention in which the quinone dioximes are benzoquinone dioximes.

  In the present invention, by using a rubber composition having a specific composition for the rubber layer in which the core wire is embedded, the adhesive property with the core wire is good and the tear resistance is excellent, and the pop-out of the core wire is suppressed. Can provide a power transmission belt capable of In addition, the ethylene-vinyl ester copolymer and the ethylene / α-olefin rubber do not contain a halogen and therefore do not give a load to the environment.

  Then, by setting the ratio of the ethylene-vinyl ester copolymer and the ethylene / α-olefin rubber within a specific range, a power transmission belt having a good balance of modulus, tear resistance and adhesiveness can be obtained. Moreover, it can be set as the structure which was more excellent in tear resistance and adhesiveness by selecting the ethylene-vinyl ester copolymer whose vinyl ester content exists in a specific range. Further, by selecting benzoquinone dioximes as oximes, a power transmission belt having high hardness and firmly adhered to the core can be obtained.

  As an example of the power transmission belt according to the present invention, FIG. 1 shows a sectional perspective view of a toothed belt 1 and FIG. 2 shows a sectional perspective view of a V-ribbed belt 10.

  The toothed belt 1 of 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. Here, the rubber layer in which the core wire 3 is embedded refers to a rubber layer constituting the back portion 4.

  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, and thus the tooth portion 2 also has the same rubber layer as the back portion 4.

  The V-ribbed belt 10 shown in FIG. 2 includes an extended portion 12 made of a cover canvas 15, an adhesive layer 14 in which a core wire 13 is embedded, and a compression portion 16 that is an elastic layer below the adhesive layer. The compression portion 16 has a plurality of trapezoidal ribs having a substantially triangular cross section extending in the belt longitudinal direction. Here, the rubber layer in which the core wire 13 is embedded refers to a rubber layer constituting the adhesive layer 14.

  In addition to the above configuration, the V-ribbed belt includes, for example, a V-ribbed belt in which the adhesive layer 14 is not disposed and the extending portion 12 is formed of a rubber composition without attaching the cover canvas 15 to the back surface. At this time, the core wire 13 is embedded in the belt main body at the boundary region between the extension portion 12 and the compression portion 16. When the V-ribbed belt has such a configuration, the rubber layer in which the core wire 13 is embedded refers to the rubber layer that constitutes the extension portion 12 and the compression portion 16, respectively. At this time, considering the adhesiveness between the core wire 13 and the belt body, it is desirable that the compression portion 16 is made of a rubber composition not containing short fibers. Further, it is desirable to form the stretched portion 12 with a rubber composition containing short fibers.

  As the core wires 3 and 13 used in the present invention, a cord composed of polyethylene terephthalate fiber, polyethylene naphthalate fiber, polytrimethylene terephthalate fiber, polybutylene terephthalate fiber, glass fiber, aramid fiber, or the like 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 core wire is preferably subjected to an adhesive treatment. For example, (1) After impregnating the untreated cord into a tank containing a treatment liquid selected from an epoxy compound and an isocyanate compound, and pre-dip (2) 160 Stretching is performed for 30 to 600 seconds in a drying oven set at a temperature of ˜200 ° C., (3) followed by immersion in a tank containing an adhesive solution made of RFL solution, and (4) stretching set at a temperature of 210 to 260 ° C. It can be stretched by −1 to 3% through a heat setting processor for 30 to 600 seconds to form a stretched cord.

  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 progresses too much and gels. On the other hand, if it exceeds 2/1, the reaction between resorcin and formaldehyde does not progress so much. To do.

  Examples of the rubber latex include styrene-butadiene-vinylpyridine terpolymer, hydrogenated nitrile rubber, chloroprene rubber, and nitrile rubber.

  Further, the solid content mass ratio between the resorcin-formaldehyde initial condensate and the rubber latex is preferably 1: 2 to 1: 8, and if this range is maintained, it is suitable for enhancing the adhesive force. 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.

  Further, a vulcanization accelerator or a vulcanizing agent may be added to the RFL liquid, and the vulcanization accelerator to be added is a sulfur-containing vulcanization accelerator. Specifically, 2-mercaptobenzothiazole (M ) And salts thereof (for example, zinc salts, sodium salts, cyclohexylamine salts, etc.) thiazoles such as dibenzothiazyl disulfide (DM), sulfenamides such as N-cyclohexyl-2-benzothiazylsulfenamide (CZ) , Thiurams such as tetramethylthiuram monosulfide (TS), tetramethylthiuram disulfide (TT), dipentamethylenethiuram tetrasulfide (TRA), sodium di-n-butyldithiocarbamate (TP), zinc dimethyldithiocarbamate ( PZ) Dithiocarbamine such as zinc diethyldimethyldithiocarbamate (EZ) There are salts and the like.

  Examples of the vulcanizing agent include sulfur, metal oxides (zinc oxide, magnesium oxide, lead oxide), peroxides, and the like, which are used in combination with the above vulcanization accelerator.

  The rubber layer in which at least the cords 3 and 13 of the belt body are embedded is composed of ethylene / vinyl ester copolymer and ethylene / α-olefin rubber as rubber components in a weight ratio of 5/95 to 100/0, modulus and tear resistance. Considering the balance between the property and the adhesiveness, it is more preferably composed of a rubber composition containing 10/90 to 60/40. With the above configuration, a power transmission belt having excellent adhesion to the cores 3 and 13 and excellent tear resistance can be obtained. In addition, 100/0 containing ethylene-vinyl ester copolymer and ethylene / α-olefin rubber as a rubber component indicates a state in which ethylene-vinyl ester copolymer is contained and ethylene / α-olefin rubber is not contained. .

  The ethylene / α-olefin rubber is a copolymer of ethylene and α-olefin (propylene, butene, hexene, or octene), or a copolymer of ethylene, the α-olefin, and a nonconjugated diene. Refers to rubber made of ethylene-propylene rubber (EPM) or ethylene-propylene-diene copolymer (EPDM). Examples of the diene component include non-conjugated dienes having 5 to 15 carbon atoms such as ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, and methylene norbornene.

  In the ethylene-vinyl ester copolymer, when the hydrocarbon of the ester becomes long, the relative amount of the ester bond decreases and the polarity becomes low. Therefore, it is desirable that the hydrocarbon is as short as possible. Examples of the vinyl ester of the ethylene-vinyl ester copolymer include vinyl propionate, vinyl acetate, vinyl caproate, vinyl caprylate, vinyl laurate, and vinyl stearate. Among them, vinyl acetate, that is, ethylene- Vinyl acetate copolymer (EVA) is preferred. Further, when an ethylene-vinyl ester copolymer having a vinyl ester content of 30 to 70% by weight is selected, a structure having more excellent tear resistance and adhesiveness can be obtained. If it is less than 30% by weight, the tear resistance and adhesiveness are not sufficient, and if it exceeds 70% by weight, the elasticity as rubber is impaired, belt deformation increases, dimensional changes increase, and the belt life decreases.

  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 preferably used alone or as a mixture in the range of 0.5 to 8 parts by weight with respect to 100 parts by weight of rubber.

  The rubber composition contains 0.5 to 13 parts by weight of N, N′-m-phenylene dimaleimide and / or quinonedioxime with respect to 100 parts by weight of the rubber component. N, N'-m-phenylene dimaleimide and quinonedioximes act as co-crosslinking agents, and if less than 0.5 parts by mass, the effect of addition is not significant, and if it exceeds 13 parts by mass, the tearing force and adhesive strength are Decreases rapidly. At this time, when N, N'-m-phenylene dimaleimide is selected as the co-crosslinking agent, the crosslink density is increased, and when quinonedioxime is selected, the tear resistance is excellent.

  Examples of quinone dioximes include p-benzoquinone dioxime, p, p'-dibenzoquinone dioxime, and tetrachlorobenzoquinone poly (P-dinitrobenzoquinone). Of these, benzoquinone dioximes such as p-benzoquinone dioxime and p, p'-dibenzoquinone dioxime are preferred in view of adhesiveness and crosslink density.

  In addition, other rubber compounds such as enhancers such as carbon black and silica, fillers such as calcium carbonate and talc, plasticizers, stabilizers, processing aids, and colorants are used as necessary. What is used is used.

  It should be noted that although the rubber composition in which at least the core wire of the power transmission belt body is embedded is composed of the rubber composition, it is needless to say that the rubber composition that constitutes the power transmission belt body. All can be composed of the rubber composition.

  In the toothed belt 1 shown in FIG. 1, the rubber layer in which the core wire 3 is embedded is the back portion 4, but the tooth portion 2 can also be composed of the rubber composition. Further, for example, the back portion 4 in which the core wire is embedded can be constituted by the rubber composition, and the tooth portion 2 can be constituted by another rubber composition.

  In the V-ribbed belt 10 shown in FIG. 2, the rubber layer in which the core wire 13 is embedded is the adhesive layer 14, but the compression layer 16 can also be composed of the rubber composition. Further, for example, the adhesive layer 14 in which the core wire is embedded can be composed of the rubber composition, and the compression portion 16 can be composed of another rubber composition.

  In addition, since the rubber composition is excellent in adhesiveness to fibers, the rubber layer that is in contact with the fiber member other than the core wire is also composed of the rubber composition, so that the belt main body and the fiber member are well bonded. Is obtained. For example, in the toothed belt 1, if the rubber layer in contact with the tooth cloth 5, that is, the tooth portion 2 is formed of the rubber composition, peeling of the tooth cloth 5 can be suppressed.

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

  The cover canvas 15 used for the V-ribbed belt 10 is a fiber base selected from woven fabric, knitted fabric, non-woven fabric, 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. In the case of a woven fabric, these yarns are woven by plain weaving, twill weaving, satin weaving or the like.

  The cover canvas 15 is preferably immersed in a resorcin-formaldehyde-latex liquid (RFL liquid) according to a known technique. Further, after being immersed in the RFL solution, friction can be performed by rubbing the unvulcanized rubber into the cover canvas 15 or immersion can be performed in a soaking solution in which the rubber is dissolved in a solvent. 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 mass.

  The power transmission belt is not limited to the above-described toothed belt and V-ribbed belt, and a V belt, a flat belt, and the like also belong to the technical scope of the present invention.

  Hereinafter, a description will be given with specific examples.

  The physical properties of the unvulcanized rubber of the rubber composition shown in Table 1 and the physical properties of the vulcanized rubber press-vulcanized at 165 ° C. for 30 minutes were measured. The viscosity was evaluated according to JISK6300, the hardness according to JISK6253, 100% modulus, breaking strength, breaking elongation according to JISK6251, and tearing according to JISK6252. In addition, the test piece was produced according to JISK6250. Further, the glass fiber cord subjected to the adhesion treatment is arranged in a width of 25 mm on a rubber sheet having a thickness of 4 mm having the composition shown in Table 1, vulcanized at 165 ° C. for 30 minutes by applying a pressure of 2.0 MPa with a press plate, A sample for adhesion test was prepared. The adhesion strength of each sample was measured according to JISK6256. The results are shown in Table 2.

In Comparative Example 1 using TAIC as a co-crosslinking agent, the vulcanized rubber has low elongation and tear strength, and is poor in adhesion to the cord. Further, in Comparative Example 2 in which an appropriate amount or more of maleimide was blended as a co-crosslinking agent, the tearing force and the adhesiveness were remarkably lowered, which was impossible in practical use. Further, Comparative Examples 3 and 4 using EPDM which is ethylene / α-olefin alone as a rubber component had extremely low adhesion to the core wire. On the other hand, for example comparative examples, tear resistance, Ri is divided the adhesion is improved, by blending the EVA and EPDM in a specific ratio, the adhesion and the tear resistance of the balance between modulus It turned out to be excellent. Furthermore, it has been found that the adhesiveness and tear resistance are further improved by selecting EVA having an ethylene content within a specific range. Moreover, the Example which selected the benzoquinone dioxime out of the quinone dioxime compounding system was found to have high rubber hardness and excellent adhesiveness.

  The power 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 a V-ribbed belt which is a power transmission belt according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Toothed belt 2 Tooth part 3 Core wire 4 Back part 5 Tooth cloth 10 V-ribbed belt 12 Extension part 13 Core wire 14 Adhesive layer 15 Cover canvas 16 Compression part

Claims (4)

A power transmission belt in which a core wire is embedded along the longitudinal direction of the belt in a main body made of rubber, and at least the rubber layer in which the core wire is embedded has a vinyl ester content of 30 to 70% by weight as a rubber component. An ethylene-vinyl ester copolymer and ethylene / α-olefin rubber are contained in a weight ratio of 5/95 to 100/0, an organic peroxide is blended as a crosslinking agent, and N is added to 100 parts by weight of the rubber component , N′-m-phenylene dimaleimide and / or a quinonedioxime is a rubber composition containing 0.5 to 13 parts by weight of a power transmission belt. The power transmission belt according to claim 1, wherein the ethylene-vinyl ester copolymer and the ethylene / α-olefin rubber are contained as a rubber component in a weight ratio of 10/90 to 60/40.   The power transmission belt according to claim 1 or 2, wherein the ethylene-vinyl ester copolymer is an ethylene-vinyl acetate copolymer. The power transmission belt according to any one of claims 1 to 3 , wherein the quinone dioximes are benzoquinone dioximes.

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