JPH08226494A - Toothed belt - Google Patents

Abstract

PURPOSE: To provide a toothed belt capable of performing molding work of a reinforced cloth at a lower temperature than before. CONSTITUTION: A reinforced cloth 5 comprising a base layer, an adhesive layer formed on one side of the base layer, and a canvas is provided on the tooth face of a belt body 3 comprising an elastomer in the form that the base layer is positioned on the outside. Also the base layer and adhesive layer are made soften at a lower temperature than the canvas, and the reinforced cloth 5 is heated and pressurized at a lower temperature than the melting point of the base layer and adhesive layer. Thus, after the base layer and adhesive layer are made soften and a tooth form is made, the belt is cooled for solidification.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a toothed belt.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a toothed belt in which a liquid cast elastomer material such as polyurethane is used and a belt main body and teeth are integrally formed, and a reinforcing cloth is attached to cover the teeth. There is. Urethane belts with a reinforcing cloth integrally molded on the tooth surface protect the teeth when the belt is used, increasing resistance to shearing and abrasion, so it is more durable than a belt without a reinforcing cloth. There is an advantage that the property is improved.

By the way, the above-mentioned toothed belt has been manufactured as follows. First, a reinforcing cloth is impregnated with or coated with a liquid elastomer, and heated and pressed with a predetermined tooth mold to be cured or semi-cured to form a tooth profile. That is, in order to accurately attach the reinforcing cloth to the tooth profile surface portion of the toothed belt, the reinforcing cloth is sandwiched by a pair of die plates and heated and pressed to form the toothed reinforcing cloth in advance. Then, the toothed reinforcing cloth is mounted on a cylindrical inner mold, and a liquid elastomer is cast and heated by a casting method to obtain a toothed belt.

However, since the sailcloth constituting the reinforcing cloth usually has a high softening temperature, it is necessary to heat the reinforcing cloth to a certain temperature in order to mold the reinforcing cloth. There is a problem that it is decreasing.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention
An object of the present invention is to provide a toothed belt capable of performing a work of molding a reinforcing cloth at a lower temperature than conventional ones.

[0006]

Means for Solving the Problems The inventors of the present invention have found that the above-mentioned problems can be solved by adopting the following technical means as a result of earnest studies in view of the above situation, It came to completion.

That is, the toothed belt of the present invention comprises a base material layer, a reinforcing cloth composed of an adhesive layer formed on one surface of the base material layer, and a canvas, and an elastomer in a mode in which the base material layer is located outside. Having on the tooth surface of the belt body, the base material layer and the adhesive layer are softened at a temperature lower than that of the canvas, and the reinforcing cloth is at a temperature lower than the melting points of the base material layer and the adhesive layer. It is characterized in that the base material layer and the adhesive layer are softened by heating and pressurizing, and the tooth mold is modeled and then cooled and solidified.

According to the toothed belt of the present invention, the base material layer and the adhesive layer are softened at a temperature lower than that of the canvas,
The reinforcing cloth was heated and pressed at a temperature lower than the melting points of the base material layer and the adhesive layer to soften the base material layer and the adhesive layer, mold the tooth mold, and then cool and solidify. Therefore, due to the presence of the base material layer and the adhesive layer that have been softened and the tooth model has been imprinted and then cooled and solidified, the reinforcing cloth is made into a reinforcing cloth at a temperature lower than that of softening the canvas itself having a high softening temperature. It is possible to mold the tooth mold of.

The base material layer may have a higher melting point than the adhesive layer. Further, the elastomer may be a polyurethane elastomer obtained by mixing a prepolymer composed of para-phenylene diisocyanate and one or more of polyester-based polyols, polyether-based polyols and polycarbonate-based polyols with a curing agent.

In this toothed belt, for example, a reinforcing cloth having an elastomer impervious resin layer is sandwiched between a pair of mold boards, and this is heat-pressed to form a toothed reinforcing cloth.
A cylinder in which both ends of the reinforcing cloth are integrally shape-reinforced by interposing a flexible adhesive having a short curing time at both ends of the reinforcing cloth, and a tooth groove group is provided in the circumferential surface axial direction. The reinforcing cloth is wrapped around the inner mold, spirally wound around the surface of the mold, then combined with the outer mold concentrically, and a casting elastomer is injected between both molds to cure. It can be manufactured by cutting the belt molded body into slices.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the toothed belt of the present invention will be described in detail below based on embodiments.

In FIG. 1, reference numeral 1 denotes a toothed urethane belt, which is a belt main body 3 made of urethane elastomer having meshing teeth 2 at regular intervals, and is arranged in the belt main body 3 in the longitudinal direction. It is composed of a tensile body 4 and a reinforcing cloth 5 attached to the tooth surface. And the reinforcing cloth 5
Comprises a canvas 6 and an impermeable resin layer 7.

As the urethane elastomer, there is used a polyurethane elastomer prepared by mixing a prepolymer composed of para-phenylene diisocyanate and one or more of polyester-based polyols, polyether-based polyols and polycarbonate-based polyols with a curing agent. .

The polyester-based polyol is, for example, a condensate of polycarboxylic acid and low-molecular polyol,
Those having a molecular weight of 500 to 10,000 can be mentioned. Specifically, poly (ethylene adipate) (hereinafter referred to as “PEA”), poly (diethylene adipate) (hereinafter referred to as “PD
A)), poly (propylene adipate) (hereinafter "PPA"), poly (tetramethylene adipate) (hereinafter "PBA"), poly (hexamethylene adipate) (hereinafter "PHA"), Poly (neopentylene adipate) (hereinafter referred to as "PNA"), poly (nonanediol adipate), poly (nonanediol / methyloctanediol adipate), 3-methyl-
Polyol consisting of 1,5-pentanediol and adipic acid, random copolymer of PEA and PDA, PEA and P
Random copolymer of PA, random copolymer of PEA and PBA, random copolymer of PHA and PNA, or
Caprolactone polyols obtained by ring-opening polymerization of ε-caprolactone, polyols obtained by ring-opening β-methyl-δ-valerolactone with ethylene glycol, etc. (These may all have a molecular weight of 500 to 10,000. Preferred), each of which may be used alone or in combination. further,
Examples of the polyester-based polyol include a copolymer of at least one of the following acids and at least one of glycols.

(Acid) Terephthalic acid, isophthalic acid, phthalic anhydride, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecane diacid, dimer acid (mixture), paraoxybenzoic acid, trimellitic anhydride, ε-caprolactone , Β-methyl-δ-valerolactone.

(Glycol) Ethylene glycol, propylene glycol, 1,4-butanediol, 1,5
-Pentanediol, 1,6-hexanediol, neopentyl glycol, polyethylene glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, pentaerythritol, 3-methyl-1,5
-Pentanediol.

Examples of the polyether-based polyol include those obtained by ring-opening addition polymerization using an alkylene oxide (eg, ethylene oxide or propylene oxide) as an initiator with a polyhydric alcohol (eg, diethylene glycol) which is an active hydrogen compound, Specific examples thereof include polypropylene glycol (PPG), polyethylene glycol (PEG), and a copolymer of propylene oxide and ethylene oxide. Further, those having a molecular weight of 500 to 5,000, which are provided by cationic polymerization of tetrahydrofuran, can be mentioned. In particular,
Polytetramethylene ether glycol (PTMG), and tetrahydrofuran is a copolymer with other alkylene oxides. Specifically, a copolymer of tetrahydrofuran and propylene oxide, a copolymer of tetrahydrofuran and ethylene oxide Examples thereof include coalesce and the like (all of which preferably have a molecular weight of 500 to 10,000), and they may be used alone or in combination of two or more.

As the polycarbonate-based polyol,
Conventionally known polyol (polyhydric alcohol) and phosgene,
Obtained by condensation with chloroformic acid ester, dialkyl carbonate or diallyl carbonate, various molecular weights are known. Particularly preferred as such a polycarbonate polyol is 1,6-hexanediol, 1,4-butanediol, 1,3-butanediol, neopentyl glycol, or 1,5-pentanediol as the polyol. It has a molecular weight of about 500 to 10,000. For example, a polycarbonate diol represented by the following general formula 1,

[0019]

Embedded image

And the like. The structure of the polyol portion of the polycarbonate-based urethane prepolymer used in this embodiment is a polycarbonate-based polyol as described above, a random copolymer of a polycarbonate-based polyol and a polycaprolactone-based polyol, or a polycarbonate-based polyol and a polyester-based polyol. Examples thereof include a random copolymer, a mixture of a polycarbonate-based polyol, a polycaprolactone-based polyol, and a polyester-based polyol, and these may be used alone or in combination.

The method for producing the urethane prepolymer by reacting one or more of the above-mentioned polyols with paraphenylene diisocyanate is not particularly limited, and examples thereof include reaction temperature, reaction time, presence or absence of solvent, etc. Can be carried out by known methods.

To obtain the urethane elastomer used in this embodiment, the urethane prepolymer obtained as described above may be mixed with a curing agent to cure the urethane prepolymer.

The curing agent that can be used is not particularly limited and may be one that has been generally used in the past when curing a urethane prepolymer to produce a urethane elastomer. Examples thereof include polyol compounds and polyamine compounds. The polyol compound is not particularly limited, and any of primary polyol, secondary polyol, and tertiary polyol may be used. Specifically, ethylene glycol, 1,3-propanediol, 1,4-
Butanediol, 1,5-pentanediol, 1,6-
Hexanediol, propylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-pentanediol, 2,3-pentanediol, 2,5-hexane Diol, 2,4-hexanediol, 2-ethyl-1,3-hexanediol, cyclohexanediol, 2-ethyl-2- (hydroxymethyl) -1,3-
Propane diol etc. are mentioned. The polyamine compound is not particularly limited, such as diamine, triamine and tetraamine, and any of primary amine, secondary amine and tertiary amine can be used. Specifically, aliphatic amines such as hexamethylenediamine, 3,3′-dimethyl-
Alicyclic amines such as 4,4'-diaminodicyclohexylmethane, 4,4'-methylenebis-2-chloroaniline, 2,2 ', 3,3'-tetrachloro-4,4'-diaminophenylmethane, 4 , 4'-diaminodiphenyl and other aromatic amines, 2,4,6-tris (dimethylaminomethyl) phenol and the like. These curing agents may be used alone or in combination of two or more.

The method for mixing the above-mentioned curing agent and the urethane prepolymer obtained as described above to cure the urethane prepolymer is not particularly limited, and for example, for the urethane prepolymer. It can be carried out by an ordinary method including the mixing ratio of the curing agent, the curing temperature, the curing time and the like.

The polyurethane elastomer used in this embodiment may contain additives and the like. Additives that can be used in this embodiment are plasticizers, flame retardants, fillers, stabilizers, colorants and the like.

Examples of the plasticizer include dioctyl phthalate (DOP), dibutyl phthalate (DBP), dioctyl adipate (DOA), tricresyl phosphate (TC).
P), chlorinated paraffin, etc. can be used.

Examples of the flame retardant include phosphoric acid esters such as tris- (β-chloropropyl phosphate, tris-dichloropropyl phosphate and trischloroethyl phosphate, and bromine compounds such as dibromoneopentyl glycol and tribromoneopentyl alcohol. Available.

As the filler, for example, glass fiber, carbon black, calcium carbonate, talc, kaolin, zeolite, diatomaceous earth, perlite, permiculite, titanium dioxide, silicon powder and silicone oil, graphite, molybdenum disulfide and the like can be used. .

As the stabilizer, conventionally used antioxidants, ultraviolet absorbers, light stabilizers, hydrolysis inhibitors and the like can be used.

The antioxidant acts as a radical chain inhibitor / peroxide decomposer, and the former includes phenols and aromatic amines having steric hindrance.

As radical chain inhibitors, butylated hydroxytoluene, tetrakis [methylene.3 ((3 '.
5'-di-t-butyl-4hydroxyphenyl) propionate] methane, n-octadecyl-β- (4'-hydroxy-3'-5'-di-t-butylphenyl) propionate, 1,3,5 tris (4 -T-butyl / 3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, triethylene glycol bis 3 (2-t-butyl-4-hydroxy-5-methylphenyl) propionate, etc. can be used.

As the peroxide decomposing agent, 4,4'thiobis (6-t-butyl.m.cresol, dilauryl.thiodipropionate, distearylthio.dipropionate, thiophenylphosphite and the like can be used.

As the ultraviolet absorber, salicylic acid-based phenyl salicylate, Pt-butylphenyl salicylate, benzophenone-based 2,4-di-hydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n. -Octoxybenzophenone, benzotriazole-based 2 (2'-hydroxy-
5'-methylphenyl) benzotriazole, 2 (2 '
-Hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2 (2'-hydroxy-3 ', 5'-di-t-aminophenyl) benzotriazole, siale acrylate system Ethyl-2-cyano-3,5-diphenyl acrylate, 2 (2′-hydroxy-5′-t-octylphenyl) benzotriazole and the like can be used.

As the UV screen, pigments such as carbon black and zinc white can be used.

As a light stabilizer, there is a hindered amine. As a hindered amine, 2- (3,5-di-t
-Butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4)
-Piperidyl, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [[6- (1,1,
3,3-Tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [[2,2 , 6,6-Tetramethyl-4-piperidyl)
Imino]], 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,
2,2,6,6-pentamethyl-4-piperidyl) and the like can be used.

As a hydrolysis inhibitor, carbodiimide type stavaxol-1, PCD (Bayer Co.), hexamethylenetetramine, azodicarbonamide, 4-t
-Butylcatechol and the like can be used.

The method for producing the urethane prepolymer by reacting the hydroxyl group-terminated polyol with paraphenylene diisocyanate is not particularly limited, and known methods include reaction temperature, reaction time, presence or absence of solvent, etc. It can also be performed by the method.

It is necessary to react the organic polyisocyanate with the active hydrogen-containing compound so that the prepolymer thus obtained has an isocyanate group content of 1 to 20% by weight. When the isocyanate group content of the obtained prepolymer exceeds 20% by weight and becomes large, the amount of free paraphenylene diisocyanate increases and the storage stability of the urethane prepolymer becomes poor. Also,
If it is less than 1% by weight, the urethane prepolymer has a low isocyanate group content and the pot life becomes too long, resulting in poor productivity.

In the toothed belt of this embodiment, a cord made of, for example, glass fiber, steel fiber, or aramid fiber is used as the tensile member 4, but the cord is not limited to these. In this embodiment, "Kevlar" (aramid fiber manufactured by DuPont) was used.

The canvas 6 comprises a warp yarn 8 made of wooly textured yarn of synthetic fiber such as nylon fiber or polyester fiber,
The weft thread 9 made of ordinary synthetic fibers is woven. The warp yarn 8 has a monofilament diameter d of 30.
μm (single fiber fineness of about 6 denier for nylon fiber)
In particular, it is preferably 20 μm or less (fine fiber fineness of about 2.5 denier in the case of nylon fiber) or less.

The impermeable resin layer 7 is formed by forming an adhesive layer 11 having a thickness of 1/2 d to 1 d with respect to the single fiber diameter d of the warp yarn 8 on one surface of the base material layer 10. That is, when a fiber having a single fiber diameter d of 20 μm is used as the warp yarn 8, the thickness of the adhesive layer 11 is 10 to 2
Use 0 μm. Further, the base material layer 10 is easily worn by engagement with the pulley, and it is preferable to use the base material layer as thin as possible, and its thickness is suitably 10 to 30 μm.

The materials for the base material layer 10 and the adhesive layer 11 are low density polyethylene resin, high density polyethylene resin, polypropylene resin, ethylene methyl methacrylate copolymer, ethylene vinyl acetate copolymer, ethylene methacrylic acid. A copolymer, polyester resin, nylon resin, polyvinyl alcohol resin, fluororesin or the like having a lower friction coefficient than the urethane elastomer constituting the belt body 3 is used. A resin having a high melting point is used for the base material layer 10, and a resin having a low melting point is used for the adhesive layer 11. As a concrete impermeable resin layer 7, a high density polyethylene resin (melting point: about 130 ° C.) is used for the base material layer 10.
There is a two-layer film in which an ethylene methyl methacrylate copolymer (melting point: about 110 ° C.) is used for the adhesive layer 11 and these are coextruded. However, it is not limited to the two-layer film, and may be a high melting point resin film coated with a low melting point adhesive.

Then, the canvas 6 and the impermeable resin layer 7
Are stacked so that the base material layer 10 is located on the outside, and this is higher than the melting point of the adhesive layer 11 and the base material layer 10
By pressing at a temperature lower than the melting point of the adhesive layer 11
Is melting. Since the thickness of the adhesive layer 11 is 1/2 d to 1 d with respect to the single fiber diameter d of the warp yarn 8, the melted resin is at least more than the single fibers of the warp yarn 8 on the surface of the canvas 6 as shown in FIG. It will dig into a depth corresponding to the diameter of 0.5 to 1 fiber, and will partially dig into it. Therefore, the molten resin does not bite into the warp threads 8 of the canvas 6 more than necessary, and the canvas 6 and the base material layer 10 are in a state of being firmly adhered to each other via the resin that has bitten into the warp threads 8.

Next, the method for manufacturing the toothed belt of this embodiment will be described in detail. As a first step, as shown in FIG. 4, a plurality of nested tooth profiles 1 are formed on the inner contact surfaces.
4, the warp thread 8 direction is arranged in a state orthogonal to the tooth profile 14 of the lower die-equipped disc 13 between the pair of upper and lower die-equipped discs 12, 13.
In addition, the reinforcing cloth 5 is arranged so that the impermeable resin layer 7 is in contact with the lower die plate 13. This reinforcing cloth 5 is attached to the adhesive layer 1
After heating under pressure at a temperature 10 to 50 ° C. lower than the melting point of the resin of No. 1 for a predetermined time and immediately cooling, the impermeable resin layer 7 and the adhesive layer 11 are softened and then cured, as shown in FIG. The toothed reinforcing cloth 5 is obtained.

In the second step, the both ends of the toothed reinforcing cloth 5 are integrated by solidifying the flexible hot melt adhesive having a short curing time at both ends of the toothed reinforcing cloth 5. The reinforcing shape of the toothed reinforcing cloth 5 is strengthened and fixed. That is, the upper die plate 12 is removed, and both ends of the lower die plate 13 are closed with a pair of end plates 15 while the toothed reinforcing cloth 5 is attached, and as shown in FIG. A hot-melt adhesive 16 having a good curing property and having a short curing time is injected by an applicator 17 so as to be solidified and intervened at both ends of the toothed reinforcing cloth 5, and the both ends are shaped and reinforced. Then, the toothed reinforcing cloth 5 is removed from the lower die-equipped plate 13 to be in the state shown in FIG. 7.

In the third step, the toothed reinforcing cloth 5 is cut into a predetermined number of teeth and endlessly processed into a tubular shape by adhesion or fusion by a hot press, as shown in FIG.
Cylindrical inner mold 1 having tooth-shaped grooves 18 ...
The toothed reinforcing cloth 5 is fitted into 9 and attached.

In this embodiment, as described in the second and third steps, the toothed reinforcing cloth 5a whose both ends are shape-reinforced by solidifying the hot-melt adhesive is endless processed into a cylindrical shape to form a cylindrical shape. Since the tooth-shaped reinforcing cloth 5 is fitted into the inner mold 19, the toothed reinforcing cloth 5 can be easily attached to the inner mold 19.

In the fourth step, the tensile body 4 is spirally wound around the surface of the toothed reinforcing cloth 5 mounted on the cylindrical inner mold 19.

When the toothed reinforcing cloth 5 and the tensile member 4 have been attached to the inner mold 19, the inner mold 19 is inserted into the cylindrical outer mold 20 as shown in FIG. Predetermined space 2
The inner mold 19 is closed and fixed by the upper and lower lids 22 and 23 so that the inner mold 19 is assembled. And the inner and outer mold 1
After heating 9 and 20 to 100 ° C., the liquid urethane elastomer 25 in the casting container 24 is pressurized by the piston 26 at a pressure of ² Kgf / cm ² or less, and is passed through the casting pipe 27 into the space 21. The liquid urethane elastomer 25 is filled. Liquid urethane elastomer 25 in the space 21
If the liquid urethane elastomer 25 flows out from the deaeration hole 28 of the upper lid 22, the opening / closing screw 29 is screwed into the deaeration hole 28 at the time of the outflow to seal the deaeration hole 28, and the temperature is 110 ° C. for 120 minutes. , 10 to 30 Kgf / cm ²
And press molding. Then, after molding, the upper and lower lids 22 and 23 are removed, the inner and outer molds 19 and 20 are separated, the molded product is released from the mold, and the belt is cut into belts of a predetermined width to produce the toothed urethane belt of this embodiment. did.

Next, for a specific example of the toothed belt of this embodiment, a running test was conducted under the following conditions in order to examine the heat resistance of the product of the present invention and the comparative product. Inventive Products 1 to 4 The toothed belt of this embodiment was produced as follows.

The polyurethane elastomer was obtained by the following procedure. First, the polyisocyanate component (shown below in (2)) is added to the polyol component (shown below in (1)).
Is added and reacted at 85 ° C. for 1 hour under a nitrogen stream to obtain a urethane prepolymer having a terminal isocyanate group.

The isocyanate group (NCO) content (shown below) of the obtained urethane prepolymer and the viscosity at 80 ° C. (shown below) were measured. The viscosity of the prepolymer was determined by using a Haake rotary viscometer-Rotovisco RV-12.

100 parts by weight of the urethane prepolymer obtained as described above was kept warm at 80 ° C. to obtain a curing agent (hereinafter referred to as (3)
) Was added and heated at 110 ° C. for 120 minutes to complete the curing reaction.

[0054]

【Example】

(Invention product 1) (1) Polyol component has an average molecular weight (indicates number average molecular weight; hereinafter the same) of 2,0
100 parts by weight of 44 of the copolymer polyol of polycarbonate and caprolactone (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Nipporan 982R) was used. (2) Polyisocyanate component 15.6 parts by weight of paraphenylene diisocyanate (= PPDI, manufactured by DuPont) was used. (3) Curing agent 12.9 parts by weight of 2,2 ', 3,3'-tetrachloro-4,4'-diaminodiphenylmethane (= TCDAM, manufactured by Ihara Chemical Industry Co., Ltd.) was used.

Each measurement result, isocyanate group (NCO) content: 3.59% (theoretical value: 3.60%) Viscosity at 80 ° C .: 14,680 cps When a sheet-shaped molded product having the above composition was obtained by the same method The hardness (JIS A) was 89. (Invention product 2) (1) Polyol component 80 parts by weight of a polycarbonate polyol having an average molecular weight of 1,908 (Nipporan 980R, manufactured by Nippon Polyurethane Industry Co., Ltd.) and a polyester-based polyol having an average molecular weight of 2,087 (Kuraray) 20 parts by weight of Crapol L2010, trade name, manufactured by Co., Ltd. was blended and used. (2) Polyisocyanate component 16.5 parts by weight of PPDI was used. (3) Curing agent 12.7 parts by weight of TCDAM was used.

Each measurement result, isocyanate group (NCO) content: 3.53% (theoretical value: 3.71%) Viscosity at 80 ° C .: 22,930 cps When a sheet-like molded product having the above composition was obtained by the same method The hardness (JIS A) was 90. (Invention product 3) (1) Polyol component 80 parts by weight of a polycarbonate polyol having an average molecular weight of 1,908 (Nipporan 980R, manufactured by Nippon Polyurethane Industry Co., Ltd.) and a polyester-based polyol having an average molecular weight of 1,950 (Kuraray) 20 parts by weight of CRAPOL P2010 (trade name, manufactured by Co., Ltd.) was blended and used. (2) Polyisocyanate component 16.7 parts by weight of PPDI was used. (3) Curing agent 13.3 parts by weight of TCDAM was used.

Each measurement result shows that the isocyanate group (NCO) content is 3.68% (theoretical value is 3.75%), the viscosity at 80 ° C. is 15,080 cps, when a sheet-shaped molded product having the above composition is obtained by the same method. The hardness (JIS A) was 88. (Invention product 4) (1) Polyol component 80 parts by weight of a polycarbonate polyol having an average molecular weight of 1,996 (manufactured by Nippon Polyurethane Industry Co., Ltd., product name: Nipolan 980R) and polytetramethylene ether glycol having an average molecular weight of 1,986. (Hodogaya Chemical Co., Ltd., trade name PTG2000) 20 parts by weight were used by blending. (2) Polyisocyanate component 16.1 parts by weight of PPDI was used. (3) Hardener 13.0 parts by weight of TCDAM was used.

Each measurement result: Isocyanate group (NCO) content: 3.60% (theoretical value: 3.63%) Viscosity at 80 ° C .: 23,190 cps When a sheet-shaped molded product having the above composition was obtained by the same method. The hardness (JIS A) was 82.

A toothed belt having a structure as shown in FIG. 1 was produced by using each of the polyurethane elastomers in the back portion and the toothed portion. In addition, this toothed belt is of RU type and has a tooth pitch of 9.525 mm, a number of teeth of 92, a length of 34.5 inches,
The width was 0.75 inches. Comparative product 1 A toothed belt using a sulfur-containing cross-linking composition of hydrogenated nitrile rubber was produced as follows.

The hydrogenated nitrile rubber composition is 100 parts by weight of hydrogenated nitrile rubber (Zetpol: manufactured by Zeon Corporation), 40 parts by weight of carbon black, 10 parts by weight of a plasticizer,
Zinc white 5 parts by weight, stearic acid 1 part by weight, antioxidant 2
Parts by weight, 2.5 parts by weight of a vulcanization accelerator, and 0.5 parts by weight of sulfur were blended, and kneaded by a well-known means and method using a Banbury mixer, a roll, etc. to obtain a rubber sheet.

The reinforcing cloth is prepared by using the above rubber composition in an amount of 2 to 2.
Dissolve in 3.5 times the amount of solvent, and then add 20 to 30% of phenolic resin to dissolve it to prepare rubber paste,
An adhesive-treated nylon cloth was used in which the nylon cloth was dipped and then dried. As the tensile body, Kevlar was used as described above.

Using the hydrogenated nitrile rubber composition for the back part and the tooth profile part, a toothed belt was prepared by a conventionally known method. That is, after the reinforcing cloth is wound around the toothed cylindrical mold, the tensile body is spirally wound, the rubber sheet is further wound, and pressure molding and vulcanization are performed in a pressure vessel. Then, it was removed from the mold and cut into a predetermined width to produce a toothed belt.

Therefore, the above-mentioned product of the present invention and the comparative product were subjected to a high temperature environment (150) by using an apparatus as shown in FIG.
The running test was performed under (.degree. C.).

In FIG. 10, reference numeral 31 is a RU type (number of teeth = 20) driving pulley, and 32 is a RU type (number of teeth = 40) non-driving pulley. Then, the initial tension of the toothed belt 1 hung between the driving pulley 31 and the non-driving pulley 32 is φ52.
Adjust the tensioner pulley 33 of 15 mm to 15 Kgf,
The drive pulley 31 was rotated at a rotation speed of 6000 rpm, and the toothed belt 1 was run. After the start of running, the running time until the back of the toothed belt 1 cracked was measured. The results are shown in Table 1.

As is apparent from Table 1, the toothed belt using the hydrogenated nitrile rubber composition shown in Comparative Product 1 had a crack in the back portion in a short time and was inferior in heat resistance. The toothed belt using the polyurethane elastomer shown in the products 1 to 4 of the present invention has excellent heat resistance without cracks in the back portion in a short time.

[0066]

[Table 1]

Next, the product of the present invention and the comparative product are shown in FIG.
Using a device such as that shown in Fig. 0, new and heat aged products (14
A cold running test was carried out for each of those heat aged at 0 ° C. for 3, 7, 14 and 28 days.

In FIG. 10, the initial tension of the toothed belt 1 stretched between the driving pulley 31 and the non-driving pulley 32 is φ52 mm.
Adjusted to 15 Kgf with the tensioner pulley 33, and left the drive pulley 31 at the set temperature for 3 hours, and then the drive pulley 31 is rotated at 300 rpm.
Rotate at m and run the toothed belt 1 for 1 minute, then 10
Stop for a minute. After repeating this cycle for 50 cycles, the presence or absence of cracks on the back was examined, and the temperature limit of use of the belt was measured. Table 2 shows the results.

As is clear from Table 2, the toothed belt using the hydrogenated nitrile rubber composition shown in Comparative Product 1 has a
The low-temperature characteristics of the material aged for 14 days at 40 ° C suddenly deteriorated, resulting in poor cold resistance.
The toothed belts using the polyurethane elastomers shown in Nos. 4 to 4 have excellent low temperature resistance and low cold resistance even when heat aged at 140 ° C. for 28 days.

[0070]

[Table 2]

Next, in order to investigate the high load transmission of the product of the present invention and the comparative product, a running test was conducted under the following conditions. The product 5 reinforcing cloth of the present invention was obtained by the following procedure.

First, the warp yarn has a single fiber fineness of 2.06.
78 wool / inch denier (diameter 16 μm) 280 denier-nylon thread is used, and 210 weft nylon yarn is used as 85 / inch.
A canvas was woven with 2/2 twill weave. Next, using a high-density polyethylene resin (melting point 130 ° C) as the base material layer,
An ethylene methyl methacrylate copolymer (melting point: 110 ° C) is used as the adhesive layer, and the thickness of each is 15
A two-layer impermeable resin film was obtained by performing a two-layer extrusion molding so as to have a thickness of μm. Then, this impermeable resin film was superposed on the canvas so that the adhesive layer was in contact with the canvas, heated to 120 ° C. and pressed with a force of 20 Kg / cm ² to obtain a reinforcing cloth.

As the urethane elastomer, the same one as the product 2 of the present invention was used. Comparative product 2 A toothed belt using hydrogenated acrylonitrile-butadiene copolymer rubber (H-NBR) was produced. In addition,
The canvas used was the same as the product of the present invention 5, and the rubber glue used was the product of comparative product 1. Comparative product 3 A toothed belt using a commercially available urethane (Adiprene L-100: manufactured by Uniroyal Corp.) was prepared. Adiprene L
-100 was vacuum degassed at 80 ° C., 11 phr of a previously melted curing agent 4,4′-methylenebis-2-chloroaniline was added, and the mixture was stirred and then cast. As the reinforcing cloth, the same one as the product 5 of the present invention was used. Comparative product 4 A reinforcing cloth obtained by heating and pressing a film made of a high-density polyethylene resin having a thickness of 30 μm was used, using the same canvas as the product 5 of the present invention. The urethane elastomer is
The same as the product 2 of the present invention was used.

The toothed belts of the present invention product 5 and the comparative products 2 to 4 were subjected to a running test under a high temperature environment (120 ° C.) using an apparatus as shown in FIG.

In FIG. 10, the initial tension of the toothed belt 1 stretched between the driving pulley 31 and the non-driving pulley 32 is φ52 mm.
Was adjusted to 15 Kgf by the tensioner pulley 33, and the drive pulley 31 was rotated at a rotation speed of 6000 rpm to run the toothed belt 1. 500 hours after the start of driving, 100
The thickness of the reinforcing cloth at the tooth bottom after 0 hours and 2000 hours was measured, and the amount of wear was calculated by comparing with the new belt. The results are shown in Table 3.

As is clear from Table 3, the product 5 of the present invention is
The amount of wear of the reinforcing cloth at the tooth bottom of the belt in a high temperature environment is less than half that of the comparative products 2 to 4.

[0077]

[Table 3]

In the toothed belt of this embodiment, since the reinforcing cloth and the impermeable resin layer firmly adhere to each other due to the wedge effect of the adhesive layer, the case where the operating temperature is high or the high load transmission is used. In addition, wear of the reinforcing cloth on the tooth bottom of the belt is reduced, and even when used for a long period of time, peeling of the reinforcing cloth on the tooth bottom does not occur and tooth shearing does not easily occur, resulting in excellent durability.

The manufacturing method of the toothed belt of this embodiment is as follows.
Since no extra pressurizing and heating treatment is required, the manufacturing process can be simplified and the belt manufacturing cost can be reduced.

Further, the toothed belt of this embodiment using the urethane elastomer made of the prepolymer obtained by using paraphenylene diisocyanate is excellent in heat resistance and cold resistance, and is used as a timing belt in the automobile field, for example. It is more suitable for use.

[0081]

The present invention takes the above technical means, and has the following effects by adopting the above respective constituents.

A toothed belt can be formed on the reinforcing cloth at a temperature lower than that of softening the canvas itself, so that the toothed belt can be used to mold the reinforcing cloth at a lower temperature than before. Can be provided.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view illustrating an embodiment of a toothed belt of the present invention.

FIG. 2 is a partial perspective view of an impermeable resin layer for explaining an embodiment of the toothed belt of the present invention.

FIG. 3 is a partially enlarged cross-sectional view of an embodiment of a toothed belt of the present invention.

FIG. 4 is a perspective view showing a state in which a reinforcing cloth is arranged between a pair of upper and lower mold boards in the embodiment of the toothed belt manufacturing process of the invention.

FIG. 5 is a perspective view of a toothed reinforcing cloth obtained in the manufacturing process of the embodiment of the toothed belt of the present invention.

FIG. 6 is an explanatory view showing a state in which a hot melt adhesive to be solidified and interposed at both ends of the toothed reinforcing cloth is injected by an applicator in the manufacturing process of the embodiment of the toothed belt of the present invention.

FIG. 7 is a perspective view of a toothed reinforcing cloth having shape-reinforcing both ends obtained in the manufacturing process of the embodiment of the toothed belt of the present invention.

FIG. 8 is a perspective view showing a state in which a toothed reinforcing cloth is fitted and mounted in a cylindrical inner mold in the manufacturing process of the embodiment of the toothed belt of the present invention.

FIG. 9 is a cross-sectional view showing a state where the liquid urethane elastomer is filled in the space formed between the inner and outer molds in the manufacturing process of the embodiment of the toothed belt of the present invention.

FIG. 10 is an explanatory diagram of an apparatus for performing a running test of the embodiment of the toothed belt of the present invention.

[Explanation of symbols]

 3 Belt body 5 Reinforcement cloth 6 Canvas 10 Base material layer 11 Adhesive layer

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI technical display location // B32B 7/12 B32B 7/12 B29K 21:00 105: 06 (72) Inventor Shinichiro Kawahara Yamatokoriyama, Nara 172 Ikezawa, Ichizawa, Nitta Stock company, Nara factory (72) Inventor, Nobuyuki Yokoyama, 172, Ikezawa, Yamatokoriyama city, Nara, Unita stock company Company Nara factory

Claims (3)

[Claims] 1. A reinforcing cloth composed of a base material layer, an adhesive layer formed on one surface of the base material layer, and a canvas is provided on a tooth surface of a belt main body made of an elastomer in such a manner that the base material layer is located outside. In addition, the base material layer and the adhesive layer are softened at a temperature lower than that of the canvas, and the reinforcing cloth is heated and pressed at a temperature lower than the melting points of the base material layer and the adhesive layer. A toothed belt, characterized in that the layer and the adhesive layer are softened to form a tooth mold and then cooled and solidified. 2. The toothed belt according to claim 1, wherein the base material layer has a higher melting point than the adhesive layer. 3. The polyurethane elastomer, wherein the elastomer is a prepolymer composed of para-phenylene diisocyanate and one or more prepolymers of polyester polyols, polyether polyols and polycarbonate polyols, and a curing agent. Item 1. The toothed belt according to Item 1 or 2.