JP4755994B2 - Rubber reinforcing cord and rubber belt using the same - Google Patents

Description

  The present invention relates to a rubber reinforcing cord that is used for reinforcing rubber products such as rubber belts and tires and improves the bending resistance of the rubber products, and a rubber belt using the same.

  2. Description of the Related Art Rubber reinforcing cords including reinforcing fibers such as glass fibers are widely used as reinforcing materials for rubber products that repeatedly receive bending stress, such as rubber belts and tires. The reinforcing cord is required to have a high elastic modulus and strength, and to be less prone to elongation and bending fatigue. Further, since the reinforcing cord is used in a state of being embedded in a matrix rubber having a predetermined shape, it is required to have excellent adhesion to the matrix rubber and difficult to peel off from the matrix rubber during use.

  One type of rubber belt is a toothed belt used for driving a camshaft of an internal combustion engine, such as an automobile engine. A toothed belt is also called a timing belt, and its dimensional stability is particularly important in order to accurately synchronize the timing between the cam and the crank. In recent years, toothed belts have been used not only for driving camshafts but also for driving auxiliary machinery such as injection pumps, and have been required to be narrower due to smaller engines. Problems such as a decrease in belt strength and elongation due to an increase in size have been pointed out.

  In such a situation, as a glass fiber used for the reinforcing cord, in addition to the conventionally used non-alkali glass, for example, E glass, so-called “high-strength glass” fiber is being used. Yes.

  In Japanese Utility Model Publication No. 5 (1993) -44607, a rope containing 500 to 800 filaments is formed by bundling high-strength glass filaments having a diameter of 6 to 8 μm, forming a strand, and twisting a predetermined number of the strands. A toothed belt is disclosed that includes a reinforcing cord that is formed and top-twisted 9-12 ropes in a direction opposite to the above-mentioned twist.

  Japanese Patent Publication No. 5 (1993) -67651 discloses a first layer containing a resorcin-formaldehyde condensate and a rubber latex on the surface of a core made of high-strength glass fiber having a diameter of 8 μm or less, an isocyanate, a halogen-containing polymer, A reinforcing cord in which a vulcanizing agent and a second layer containing methacrylate or acrylate are sequentially formed is disclosed.

  In JP-A-11 (1999) -158744, a strand in which 200 to 2000 high-strength glass filaments having a diameter of 3 to 6 μm are bundled with a sizing agent is formed, and from 1 to 10 strands described above, 500 to 5000 are formed. After forming a yarn having a wire diameter of 50 to 150 tex containing a filament and forming a coating layer containing a predetermined material on the surface of the yarn, a reinforcing cord that has undergone the steps of under-twisting, combined yarn, and over-twisting Is disclosed. Examples of the predetermined material include resorcin-formaldehyde condensate, vinylpyridine-styrene-butadiene terpolymer latex, chlorosulfonated polyethylene latex, nitrile group-containing highly saturated polymer latex, and the like.

  In JP-A-11 (1999) -217739, two or more yarns in which a coating layer containing a resorcin-formaldehyde condensate and a rubber latex is formed on the surface of a strand in which high-strength glass filaments having a diameter of 8 to 10 μm are bundled are twisted. A combined reinforcing cord having a diameter of 0.8 to 1.1 mm is disclosed. In the reinforcing cord, a coating layer different from the coating layer may be further formed after twisting two or more of the yarns.

  In JP-A-11 (1999) -241275, a treatment agent containing resorcin-formaldehyde condensate and rubber latex is applied to fibers and then dried and cured to form a first coating layer. A reinforcing cord is disclosed in which a treatment agent containing a rubber precursor, a vulcanizing agent and a maleimide-based vulcanization aid is applied to the surface of the material and dried and cured to further form a second coating layer.

  However, even when a high-strength glass filament is used, problems such as elongation of the belt and reduction of the strength of the belt occur when used under a high load as required in recent years.

  Therefore, the present invention provides a rubber reinforcing cord that can withstand use under a high load as compared with a conventional rubber reinforcing cord provided with E glass fiber or high strength glass fiber, and a rubber belt using the same. Objective.

The rubber reinforcing cord of the present invention is a rubber reinforcing cord provided with a strand in which glass filaments are bundled, and the glass composition constituting the filament is expressed in weight%,
SiO ₂ 10~40%
Al ₂ O ₃ 10-30%
MgO 0-5%
CaO 0-5%
SrO 0-5%
BaO 0-5%
MgO + CaO + SrO + BaO 0-5%
ZnO 0-5%
B ₂ O ₃ 0-5%
Y ₂ O ₃ 0-50%
La ₂ O ₃ 0-60%
Y ₂ O ₃ + La ₂ O ₃ 20-60%
TiO ₂ 0-10%
ZrO ₂ 0-10%
Is included.

  The rubber belt of the present invention includes the rubber reinforcing cord of the present invention, and the rubber reinforcing cord is embedded in a matrix rubber having a predetermined shape.

FIG. 1 is an exploded perspective view schematically showing an example of the rubber belt of the present invention.

  The rubber reinforcing cord of the present invention (hereinafter also simply referred to as “cord”) has the same tensile strength as that of a conventional cord by defining the composition of the glass composition constituting the glass filament as described above. A cord that can be endured by use under a high load, such as being able to reduce elongation while being held above, can be obtained. For this reason, the rubber belt provided with the cord of the present invention is superior in strength compared to the rubber belt provided with the conventional cord, and the rubber belt excellent in bending fatigue resistance, in which elongation of the belt and reduction in strength are suppressed during use. can do.

The tensile elastic modulus (hereinafter simply referred to as “elastic modulus”) of the glass filament provided in the cord of the present invention is usually 98 GPa (10000 kgf / mm ² ) or higher, and is 109 GPa or higher by optimizing the composition of the glass composition. be able to. The upper limit of the elastic modulus is not particularly limited, but can be up to about 123 GPa (12500 kgf / mm ² ). The elastic modulus of a general high-strength glass filament is about 92 GPa, and the elastic modulus of a filament made of E glass (E glass filament) is about 86 GPa. In the cord of the present invention, it is considered that the resistance to use under a high load can be further improved by providing such a glass filament having a higher elastic modulus than the conventional one.

  Table 1 below shows the composition of the glass composition (glass composition A) together with the composition of general high-strength glass and E glass.

  As long as the elastic modulus of the glass filament is not significantly reduced, the glass composition A contains various components other than those shown in Table 1, for example, impurities derived from industrial glass, clarifiers for the purpose of defoaming during melting, and the like. May be included. Examples of impurities derived from industrial glass include iron oxide. The content of these components in the glass composition A is preferably less than 0.5% by weight. In this case, it can be said that the glass composition A constituting the filament is substantially composed of the components shown in Table 1. . That is, the expression “substantially” is intended to allow a trace component contained in a range of less than 0.5% by weight.

  It is preferable that the glass composition A does not substantially contain an alkali metal oxide, that is, the alkali metal oxide content is less than 0.5% by weight.

  The reason for limiting the composition of the glass composition A will be described. In the following description, all percentages indicating the composition are% by weight.

(SiO ₂ )
SiO ₂ (silicon dioxide) is an essential component for forming a glass skeleton, and also has an effect of improving chemical durability as a filament. When the content of SiO ₂ is less than 10%, the chemical durability of the glass decreases. If the content of SiO ₂ exceeds 40%, the melting temperature of the glass becomes high, and it becomes difficult to uniformly melt the glass raw material. The content of SiO ₂ is preferably in the range of 25% to 35%.

(Al ₂ O ₃ )
Al ₂ O ₃ (aluminum oxide) is an essential component having an effect of adjusting the devitrification temperature and melt viscosity at the time of glass formation. Al ₂ O ₃ also has an action of improving the water resistance of the filament. When the content of Al ₂ O ₃ is less than 10%, it is difficult to obtain these effects sufficiently. When the content of Al ₂ O ₃ exceeds 30%, the melting temperature of the glass becomes high, and it becomes difficult to uniformly melt the glass raw material. The content of Al ₂ O ₃ is preferably in the range of 15% to 25%.

(MgO, CaO, SrO, BaO)
These components have the effect | action which adjusts the devitrification temperature and melt viscosity at the time of glass formation, and 5% or less may be contained in the glass composition A. If the total content of each component (MgO + CaO + SrO + BaO) exceeds 5%, the devitrification temperature rises and it becomes difficult to spin the glass filament. Therefore, the total is set to 5% or less.

  The content of these components is preferably in the range of 1% to 4%. The total content is preferably in the range of 1% to 4%.

  When the glass composition A contains these components, the spinnability of the glass filament can be improved. That is, it is preferable that the glass composition A contains at least one selected from MgO, CaO, SrO, and BaO. Moreover, this effect can be improved more by including two or more types than the glass composition A includes any one of these components. In order to suppress an increase in the devitrification temperature due to an increase in the total content, when the glass composition A contains these components, it contains at least two selected from MgO, CaO, SrO and BaO. Is preferred.

(ZnO)
ZnO (zinc oxide) has the effect of improving the meltability and chemical durability of the glass, and may be contained in the glass composition A by 5% or less. If the ZnO content exceeds 5%, the glass tends to be devitrified or the meltability of the glass is lowered. The content of ZnO is preferably in the range of 1% to 4%.

  When the glass composition A contains ZnO, the spinnability of the glass filament can be improved. That is, it is preferable that the glass composition A contains ZnO.

(B ₂ O ₃ )
B ₂ O ₃ (boron oxide) has an effect of improving the meltability of the glass may contain less than 5% in the glass composition A. When the content of B ₂ O ₃ exceeds 5%, the alkali resistance of the glass decreases. The content of B ₂ O ₃ is preferably in the range of 2% to 5%.

When the glass composition A contains B ₂ O ₃ , the spinnability of the glass filament can be improved. That is, it is preferable that the glass composition A contains B ₂ O ₃ .

(Y ₂ O ₃ , La ₂ O ₃ )
Y ₂ O ₃ (yttrium oxide) and La ₂ O ₃ (lanthanum oxide) are components having an action of increasing the elastic modulus of glass, and the glass composition A contains at least one selected from both. To do. Further, Y ₂ O ₃ and La ₂ O ₃ also has function of improving the alkali resistance of the glass.

The content of Y ₂ O ₃ is in the range of 0% to 50%, preferably in the range of 15% to 40%. The content of La ₂ O ₃ is in the range of 0% to 60%, and preferably in the range of 10% to 50%. When the total content of Y ₂ O ₃ and La ₂ O ₃ (Y ₂ O ₃ + La ₂ O ₃ ) is less than 20%, it becomes difficult to obtain a filament having a sufficient elastic modulus. If Y ₂ O ₃ + La ₂ O ₃ exceeds 60%, the melting temperature of the glass becomes high, and it becomes difficult to uniformly melt the glass raw material. Y ₂ O ₃ + La ₂ O ₃ is preferably 36% by weight or less.

When glass composition A contains both Y ₂ O ₃ and La ₂ O ₃ , the elastic modulus of the filament can be further improved while suppressing an increase in the melting temperature of the glass, so that the dissociation energy per unit volume is relatively It is preferable that the content ratio of Y ₂ O ₃ is large compared to the content ratio of La ₂ O ₃ with relatively low energy.

(TiO ₂ , ZrO ₂ )
TiO ₂ (titanium oxide) and ZrO ₂ (zirconium oxide) are components having an action of improving the melting property and chemical durability of glass, and each of the glass composition A may contain 10% or less. . If the content of each of TiO ₂ and ZrO ₂ exceeds 10%, the meltability of the glass deteriorates, and the glass is easily devitrified, making it difficult to spin the filament.

  The diameter (filament diameter) of the glass filament included in the cord of the present invention may be in the range of 3 μm to 11 μm. When the filament diameter is less than 3 μm, in order to obtain sufficient initial strength as a cord, more filaments are bundled into one strand, more strands are bundled, or twisted to form a yarn Need to do. At this time, unevenness is likely to occur in the arrangement of filaments or strands, so that the resistance to bending fatigue as a cord may be reduced, or in some cases, sufficient initial strength may not be obtained. On the other hand, if the filament diameter exceeds 11 μm, the cord is difficult to bend and it is difficult to ensure sufficient bending fatigue resistance.

  In the cord of the present invention, one strand may contain 100 to 2000, preferably 200 to 600, glass filaments as described above. Such a strand can be formed by bundling a predetermined number of filaments spun with a sizing agent generally used for forming the strand, for example, an elastomeric sizing agent, when the filament is spun. The formed strand may be wound around a collet or the like and subjected to a predetermined treatment such as drying.

  In the cord of the present invention, two or more such strands may be bundled to form a strand assembly. In this case, the aggregate preferably includes 200 to 5000 glass filaments, and more preferably includes 800 to 2000 glass filaments. Moreover, the range of the wire diameter of the said aggregate is 50 tex (tex)-150 tex, and the range of 50 tex-100 tex is more preferable. The number of strands that are bundled to form an aggregate is not particularly limited, but as the number of strands to be bundled increases, the filament arrangement in the aggregate tends to be non-uniform, and the strength and the like when cords tend to decrease. Therefore, the number is preferably 10 or less, and more preferably 6 or less.

  In the cord of the present invention, the strand may be covered with the first coating layer formed by applying the treatment liquid A containing at least one selected from resorcin-formaldehyde condensate and a vulcanizing agent and latex. Good. By covering the strand with the first coating layer, the adhesion between the cord of the present invention and the matrix rubber in which the cord is embedded can be improved. The first coating layer may cover one strand or may cover a strand assembly in which two or more strands are bundled.

  The type of latex is not particularly limited, and examples thereof include vinylpyridine-styrene-butadiene terpolymer (VP) latex, chlorosulfonated polystyrene (CSM) latex, acrylonitrile-butadiene copolymer (NBR) latex, and nitrile group-containing highly saturated weight. What is necessary is just to be at least 1 sort (s) chosen from united latex. By using these materials, the heat resistance and water resistance of the cord can be improved. Nitrile group-containing highly saturated polymers include NBR hydrogenated material (H-NBR), such as acrylonitrile-containing copolymer or terpolymer hydrogenated material, or butadiene-ethylene-acrylonitrile terpolymer. Examples thereof include materials containing acrylonitrile and saturated hydrocarbon as structural units.

  The resorcin-formaldehyde condensate (RF) is not particularly limited, and a novolac type, a resole type, or a mixed type thereof may be used. The molar ratio of resorcinol (R) to formaldehyde (F) in RF is preferably R: F = 1: 1-3. RF is generally marketed as a liquid containing a solid content, but a solid content of about 5 wt% to 10 wt% can be preferably used.

  The vulcanizing agent is not particularly limited, and may be at least one selected from, for example, a maleimide compound and an organic diisocyanate compound. When the treatment liquid A contains a vulcanizing agent, the content of the vulcanizing agent in the treatment liquid A may be in the range of 5 to 100 parts by weight, preferably 20 to 100 parts by weight with respect to 100 parts by weight of the solid content of the latex. The range is 75 parts by weight. In this case, the balance between the flexibility of the cord and the adhesion to the matrix rubber can be improved.

  Although it does not specifically limit as an organic diisocyanate compound, For example, hexamethylene diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), toluene diisocyanate, xylene diisocyanate, naphthalene diisocyanate, methylene bis (phenyl isocyanate) etc. may be used.

  The treatment liquid A may contain one or more kinds of these organic diisocyanate compounds. For substances in which isomers relating to substituents exist, such as toluene diisocyanate and methylenebis (phenylisocyanate), It may be a mixture of Moreover, you may use an organic diisocyanate compound in the state which protected the isocyanate group by phenols or lactams.

  The maleimide compound is not particularly limited, and for example, bismaleimide, phenylmaleimide, diphenylmethane-4,4'-bismaleimide and the like may be used.

  The content (concentration) of the solid content in the treatment liquid A is preferably in the range of 10% by weight to 40% by weight, and more preferably in the range of 25% by weight to 35% by weight. When the content is too small, it is difficult to form the first coating layer. When the content is too large, it is difficult to control the amount of the treatment liquid A applied to the strands, and the thickness of the first coating layer becomes uneven. It becomes easy.

  The treatment liquid A may contain bases for adjusting the pH, such as ammonia, as necessary, and may further contain a stabilizer, an antiaging agent, and the like. The treatment liquid A may contain a filler such as carbon black. In this case, the treatment liquid A can be a cord that is more excellent in adhesion to the matrix rubber.

  For forming the first coating on the strand, a method generally used for manufacturing a cord may be applied. For example, the strand (including the aggregate) may be continuously dipped in a coating bath containing the processing solution A, and after the strand is lifted from the coating bath, the excess processing solution may be removed and dried as necessary. The strand on which the first coating is formed may be used as a cord as it is, or may be subjected to various treatments such as twisting and second coating layer formation described below as required.

  The first coating layer may be formed in an amount corresponding to about 10 wt% to 30 wt% with respect to the weight of the strand.

  The cord of the present invention may have a structure in which two or more yarns formed by twisting the strands coated with the first coating layer are bundled and further twisted. In this case, the strength is further improved, and the cord can be made more excellent in bending fatigue resistance. The number of lower twists may be about 0.5 to 4 times, preferably about 1.2 to 3 times per 2.54 cm (1 inch) in the length direction. The yarn formed by under twisting is bundled about 2 to 20, preferably 6 to 15, and then 0.5 to 3 times per 2.54 cm in the length direction, preferably 1 to 2. It only needs to be twisted about 8 times.

  The cord of the present invention may be covered with a second covering layer containing rubber. In this case, it can be set as the code | cord | chord which the adhesiveness with matrix rubber improved more.

  The type of rubber is not particularly limited, and may be appropriately selected depending on the type of matrix rubber. For example, when the matrix rubber is a nitrile group-containing highly saturated polymer, the second coating is superior in adhesiveness. It is preferred that the layer contains CSM as the rubber. Further, for example, when the matrix rubber is a mixed rubber in which poly (zinc methacrylate) (ZDMA) is dispersed in a nitrile group-containing highly saturated polymer, the second coating layer is used as the rubber as a nitrile group because it is superior in adhesiveness. It is preferable to contain a highly saturated copolymer or a mixed rubber having the same composition as the matrix rubber.

  The second coating layer is made of, for example, a strand (including an aggregate), a strand (including an aggregate) covered with the first coating layer, or a yarn in which a strand is further twisted, rubber, or rubber. After impregnating the processing solution B in which the precursor is dissolved, it may be formed by drying. CSM and nitrile group-containing highly saturated polymers dissolve in aromatic hydrocarbons such as benzene, toluene and xylene, halogenated hydrocarbons such as trichloroethylene, ketones such as methyl ethyl ketone, and esters such as ethyl acetate. B may include these organic substances as a solvent.

  The treatment liquid B may contain a vulcanizing agent. Examples of the vulcanizing agent include sulfur, dicumyl peroxide, 1,3-bis (t-) in addition to the maleimide compound and organic diisocyanate compound described above. Organic peroxides such as butylperoxy-m-isopropyl) benzene, aromatic nitroso compounds such as p-dinitronaphthalene and p-dinitrosobenzene may be used. The treatment liquid B may contain an inorganic filler, an anti-aging agent, a vulcanization aid, a plasticizer, and the like as necessary.

  The content of the substance other than the solvent (rubber, vulcanizing agent, etc.) in the treatment liquid B may be set as appropriate depending on the type of the substance, but is in the range of about 3 wt% to 25 wt%, preferably 5 wt% to If it is the range of about 15 weight%, formation of a 2nd coating layer will become favorable. The content of the rubber or rubber precursor in the substance other than the solvent is preferably about 20% by weight to 60% by weight. When the treatment liquid B contains a vulcanizing agent, the content of the vulcanizing agent in the substance other than the solvent is The range of about 0.5 wt% to 30 wt% is preferable.

  When the second coating layer is formed, for example, the surface of a strand (including an aggregate) or twisted yarn is converted into an amount of a substance other than the solvent with respect to the weight of the strand. The treatment liquid B may be attached in an amount of about 15% to 15% by weight, preferably about 2% to 6% by weight.

  The wire diameter of the cord of the present invention may be appropriately set depending on the use of the cord. For example, when the cord of the present invention is used for a timing belt of an automotive engine, the wire diameter of the cord is usually in a range of 0.8 mm to 1.45 mm, and the number of filaments included in the strand or the strand included in the yarn The wire diameter of the cord can be set by adjusting the number of wires. In the case of a timing belt for an automobile engine, if the wire diameter of the cord is less than 0.8 mm, the strength, typically the tensile strength, may be insufficient when used under a high load. On the other hand, if the wire diameter of the cord exceeds 1.45 mm, the cord strength is sufficient, but the resistance to bending stress (bending fatigue resistance) may be reduced.

  The cord of the present invention can be used for, for example, a timing belt for a printer in addition to the timing belt of the internal combustion engine.

  The structure and configuration of the cord of the present invention are not particularly limited as long as the cord includes a strand in which the glass filaments are bundled.

  FIG. 1 shows an example of the rubber belt of the present invention. A rubber belt 1 shown in FIG. 1 includes a rubber reinforcing cord 2 according to the present invention, and the cord 2 is embedded in a matrix rubber 3 having a toothed belt shape. In the belt 1 shown in FIG. 1, the extension directions of the cords 2 are aligned with the circumferential direction of the belt 1, and the cords 2 are arranged in parallel to each other in the width direction of the belt 1. On the surface of the matrix rubber 3 where the teeth 4 are formed, a tooth cloth 5 impregnated with rubber is disposed for the purpose of suppressing wear of the surface.

  The structure and configuration of the rubber belt of the present invention are not particularly limited as long as the rubber reinforcing cord of the present invention is provided and the cord is embedded in a matrix rubber having a predetermined shape. What is necessary is just to set the shape of matrix rubber suitably according to a use and characteristic required as a rubber belt.

  The production method of the rubber belt of the present invention may be a general production method of a rubber belt provided with a reinforcing cord.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples.

Example 1
First, a glass raw material was melted to form a melt so as to have a composition (% by weight) shown in Table 2 below, and a glass filament (diameter 7 μm) was formed by spinning from a nozzle hole of a bushing. At this time, a bushing made of a platinum (Pt) 80-rhodium (Rh) 20 alloy was used so that higher temperature melting was possible as compared with a conventional spinning device for high-strength glass.

  It was 109.8 GPa when the tensile elasticity modulus of the formed filament was measured. The elastic modulus was measured using an autograph (manufactured by Shimadzu Corporation, AGS-500G type). Specifically, the filament formed as described above was set on the autograph and pulled at a pulling speed of 250 mm / min. The calculation was performed based on the relationship between the load applied to the filament and the elongation of the filament.

  Next, 200 filaments formed were bundled with an elastomeric sizing agent and dried to form a strand having a wire diameter of 22.5 tex. Subsequently, three strands of this strand were combined to form a 70-tex strand assembly including 600 filaments. The aggregate was coated with a treatment liquid A-1 having the composition shown in Table 3 below and then dried to obtain a strand aggregate covered with the first coating layer. The coating of the treatment liquid A-1 was performed so that the solid content in the treatment liquid A was 20 parts by weight with respect to 100 parts by weight of the aggregate, and the drying was performed by holding in an atmosphere of 280 ° C. for 2 minutes. .

  Next, the assembly formed with the first coating layer is twisted 2.1 times per 2.54 cm in the length direction to form a yarn, and 11 formed yarns are combined to obtain a length. Twist further 2.1 times per 2.54 cm in the direction. In addition, the directions of the lower twist and the upper twist were opposite to each other.

  Next, the twisted yarn was coated with a treatment liquid B-1 having the composition shown in Table 4 below and then dried, and was coated with the second coating layer for reinforcing a rubber having a wire diameter of 0.95 mm. A cord (Sample 1) was produced. In applying the treatment liquid B-1, the amount of the substance other than the solvent in the treatment liquid B-1 was 3% by weight of the weight of the yarn. Drying was natural drying.

  The tensile strength and elongation at break of Sample 1 produced in this way were measured and found to be 1078 N and 3.6%, respectively. In addition, the measurement of the tensile strength and break elongation with respect to sample 1 is performed when sample 1 is set on an autograph (manufactured by Shimadzu Corp., AG-10KNI type) and pulled at a pulling speed of 250 mm / min. It was determined by measuring the load and elongation. The load corresponds to the tensile strength, and the elongation corresponds to the breaking elongation. The measuring methods of tensile strength and breaking elongation are the same in the following examples and comparative examples.

(Example 2)
The treatment liquid A-2 shown in Table 3 was used as the treatment liquid A for forming the first coating layer, and the first coating layer was formed in the same manner as in Example 1 except that the second coating layer was not formed. A rubber reinforcing cord (sample 2) having a wire diameter of 0.9 mm covered with a coating layer was produced.

  When the tensile strength and elongation at break of Sample 2 produced in this way were measured, they were 1000 N and 3.8%, respectively.

(Example 3)
The treatment liquid A-2 shown in Table 3 is used as the treatment liquid A for forming the first coating layer, and the treatment liquid B- shown in Table 5 below is used as the treatment liquid B for forming the second coating layer. A rubber reinforcing cord (sample 3) having a wire diameter of 0.95 mm covered with the second coating layer was produced in the same manner as in Example 1 except that 2 was used.

  The tensile strength and elongation at break of Sample 3 produced in this manner were measured and found to be 1029 N and 3.7%, respectively.

(Comparative Example 1)
Using U glass (manufactured by Nippon Sheet Glass Co., Ltd.) as a glass raw material, a high-strength glass filament (diameter 7 μm) was formed in the same manner as in Example 1. When the elastic modulus of the formed filament was measured in the same manner as in Example 1, it was 91.8 GPa.

  Next, a rubber reinforcing cord (sample A) having a wire diameter of 0.95 mm was produced in the same manner as in Example 1 except that the formed high-strength glass filament was used.

  The tensile strength and elongation at break of Sample A thus produced were measured and found to be 1029 N and 4.4%, respectively.

(Comparative Example 2)
A rubber reinforcing cord (sample B) having a wire diameter of 0.9 mm was produced in the same manner as in Example 2 except that the high-strength glass filament formed in Comparative Example 1 was used.

  The tensile strength and elongation at break of Sample B produced in this manner were measured and found to be 960 N and 4.4%, respectively.

(Comparative Example 3)
A rubber reinforcing cord (sample C) having a wire diameter of 0.95 mm was produced in the same manner as in Example 3 except that the high-strength glass filament formed in Comparative Example 1 was used.

  The tensile strength and elongation at break of Sample C thus produced were measured and found to be 980 N and 4.3%, respectively.

(Comparative Example 4)
Using U glass (manufactured by Nippon Sheet Glass Co., Ltd.) as a glass raw material, a high-strength glass filament (diameter 6.5 μm) was formed in the same manner as in Example 1. When the elastic modulus of the formed filament was measured in the same manner as in Example 1, it was 91.8 GPa.

  Next, using the formed high-strength glass filament and using the treatment liquid A-3 shown in Table 3 as the treatment liquid A for forming the first coating agent, the wire diameter of 0 was obtained in the same manner as in Example 1. A 95 mm rubber reinforcing cord (sample D) was prepared.

  The tensile strength and elongation at break of Sample D produced in this manner were measured and found to be 1039 N and 4.4%, respectively.

(Comparative Example 5)
E glass filament (diameter 7 μm) was formed in the same manner as in Example 1 using E glass, which is a general-purpose non-alkali glass, as a glass raw material. When the elastic modulus of the formed filament was measured in the same manner as in Example 1, it was 86.1 GPa.

  Next, a rubber reinforcing cord (sample E) having a wire diameter of 0.95 mm was produced in the same manner as in Example 1 except that the formed E glass filament was used.

  When the tensile strength and elongation at break of Sample E thus produced were measured, they were 666 N and 3.9%, respectively.

  The measurement results of tensile strength and elongation at break in Samples 1 to 3 and Samples A to E are summarized in Table 6 below.

  As shown in Table 6, the tensile strengths of Samples 1 to 3 were significantly larger than those of Sample E using E glass filaments, and were comparable to or higher than Samples A to D using high strength glass filaments. . Moreover, the elongation at break of Samples 1 to 3 could be greatly reduced as compared with Samples A to E, particularly Samples A to D using high-strength glass filaments.

Example 4
Samples 1 to 3 prepared in Examples 1 to 3 were each cut to a length of 40 mm, and then a sheet-like (size 30 mm × 40 mm, thickness 1 mm) matrix rubber precursor C having the composition shown in Table 7 below. On the surface of -1, each sample was arranged so that the length direction of each sample coincided with the long side direction of the precursor. Each sample was arranged in the range of a width of 25 mm in the short side direction on the surface of the precursor without gap so that adjacent samples were parallel to each other.

  Next, the precursor C-1 having each sample placed on the surface was hot-pressed from both sides at 150 ° C. for 30 minutes. Since the precursor C-1 contains a vulcanizing agent as its component, it became a matrix rubber vulcanized by hot pressing, and a rubber sample in which a reinforcing cord was embedded could be produced.

  Next, for the rubber sample produced as described above, the end of the matrix rubber and the end of the cord exposed from the end of the matrix rubber opposite to the end are separated into separate clips. The cord and the matrix rubber were mechanically separated and fixed (pulling test) by fixing and pulling the clip in opposite directions. The results of the destructive test are shown in Table 8 below.

  In addition, evaluation of the fracture form in this test was performed by classifying into the following three categories. In order from Category 3 to Category 1, it shows that the adhesion between the reinforcing cord and the matrix rubber is better.

  Category 1 “Rubber failure” —There is no change in the adhesive interface between the reinforcing cord and the matrix rubber, and the matrix rubber is broken. It shows that the adhesion between the reinforcing cord and the matrix rubber is good.

  Category 2 “Partial rubber failure” —Peeling occurs at the bonding interface between the reinforcing cord and the matrix rubber, and the inside of the matrix rubber is also broken. It shows that the adhesiveness between the reinforcing cord and the matrix rubber is intermediate between the above “rubber destruction” and the following “interface peeling”.

  Category 3 “Interfacial debonding” —Peeling occurs at the bonding interface between the reinforcing cord and the matrix rubber, but there is no noticeable breakage inside the matrix rubber. It shows that the adhesiveness between the reinforcing cord and the matrix rubber is inferior.

  Evaluation of the fracture mode was similarly performed in the following examples and comparative examples.

(Example 5)
As the matrix rubber precursor, the precursor cord C-2 having the composition shown in Table 7 was used, and the reinforcing cord was embedded in the same manner as in Example 4 except that the heat pressing conditions were 160 ° C. and 30 minutes. A rubber sample was prepared.

  The rubber sample prepared as described above was subjected to a destructive test in the same manner as in Example 4. The results are shown in Table 8 below.

(Comparative Example 6)
A rubber sample in which the reinforcing cord was embedded was produced in the same manner as in Example 4 except that samples A to E were used as the reinforcing cord.

  The rubber sample produced as described above was subjected to a destructive test in the same manner as in Example 4. The results are shown in Table 8 below.

(Comparative Example 7)
A rubber sample in which the reinforcing cord was embedded was produced in the same manner as in Example 5 except that samples A to E were used as the reinforcing cord.

  The rubber sample produced as described above was subjected to a destructive test in the same manner as in Example 4. The results are shown in Table 8 below.

(Example 6)
Samples 1 to 3 produced in Examples 1 to 3 were each cut to a length of 200 mm, and then a sheet-like (size 200 mm × 10 mm, thickness 1 mm) matrix rubber precursor C-1 having the composition shown in Table 7 On the surface, the length direction of each sample and the long side direction of the precursor were arranged so as to coincide with each other. Each sample was placed in a range of 10 mm in width in the short side direction on the surface of the precursor so that adjacent samples were parallel to each other. Next, hot pressing was performed in the same manner as in Example 4 to reinforce the cord. A rubber sample embedded with was prepared.

  The rubber sample produced as described above was subjected to a bending test with a load of 5 kg, and the strength of each rubber sample before and after the test was measured to evaluate the strength retention of the rubber sample. The strength retention is considered to reflect the bending fatigue resistance of the rubber sample. The bending test was performed by bending a rubber sample by reciprocating a roller having a diameter of 10 mm at a moving distance of 100 mm and a period of 20 Hz, and the test conditions were 24 hours in a 120 ° C. environment. The strength retention was determined by the formula of strength retention = (Sa−Sb) / Sa × 100 (%), where Sa is the strength of each rubber sample before the test and Sb is the strength of each rubber sample after the test.

  The strength retention results are shown in Table 8 below.

(Example 7)
As a matrix rubber precursor, a precursor cord C-2 having the composition shown in Table 7 was used, and a reinforcing cord was embedded in the same manner as in Example 6 except that the heat pressing conditions were 160 ° C. and 30 minutes. A rubber sample was prepared.

  The rubber sample produced as described above was evaluated for bending fatigue resistance by determining the strength retention rate in the same manner as in Example 6. The results are shown in Table 8 below.

(Comparative Example 8)
A rubber sample in which the reinforcing cord was embedded was produced in the same manner as in Example 6 except that samples A to E were used as the reinforcing cord.

  The rubber sample produced as described above was evaluated for bending fatigue resistance by determining the strength retention rate in the same manner as in Example 6. The results are shown in Table 8 below.

(Comparative Example 9)
A rubber sample in which the reinforcing cord was embedded was produced in the same manner as in Example 7 except that samples A to E were used as the reinforcing cord.

  The rubber sample produced as described above was evaluated for bending fatigue resistance by determining the strength retention rate in the same manner as in Example 6. The results are shown in Table 8 below.

  As shown in Table 8, in the combination of Sample 1 and matrix rubber C-2, interfacial peeling was confirmed in the destructive test. However, compared with the combination of Sample A having the same coating layer as this combination and the matrix rubber C-2, the strength retention rate could be improved.

  Similarly, in all the combinations, the strength retention of the rubber samples using Samples 1 to 3 could be improved as compared with the case where Samples A to E were used.

  The present invention can be applied to other embodiments without departing from the spirit and essential characteristics thereof. The embodiments disclosed in this specification are illustrative in all respects and are not limited thereto. The scope of the present invention is shown not by the above description but by the appended claims, and all modifications that fall within the meaning and scope equivalent to the claims are embraced therein.

  ADVANTAGE OF THE INVENTION According to this invention, compared with the conventional rubber reinforcement cord provided with E glass fiber or high-strength glass fiber, the rubber reinforcement cord which can be endured by use under high load, and a rubber belt using the same can be provided.

Claims (20)

A cord for reinforcing rubber with a strand of glass filaments,
The glass composition constituting the filament is expressed in wt%,
SiO ₂ 10~40%
Al ₂ O ₃ 10-30%
MgO 0-5%
CaO 0-5%
SrO 0-5%
BaO 0-5%
MgO + CaO + SrO + BaO 0-5%
ZnO 0-5%
B ₂ O ₃ 0-5%
Y ₂ O ₃ 0-50%
La ₂ O ₃ 0-60%
Y ₂ O ₃ + La ₂ O ₃ 20-60%
TiO ₂ 0-10%
ZrO ₂ 0-10%
Including cord for rubber reinforcement.   The rubber reinforcing cord according to claim 1, wherein the filament has a tensile elastic modulus of 98 GPa or more.   The rubber reinforcing cord according to claim 1, wherein the glass composition does not substantially contain an alkali metal oxide. The glass composition, expressed in weight percent, substantially
SiO ₂ 10~40%
Al ₂ O ₃ 10-30%
MgO 0-5%
CaO 0-5%
SrO 0-5%
BaO 0-5%
MgO + CaO + SrO + BaO 0-5%
ZnO 0-5%
B ₂ O ₃ 0-5%
Y ₂ O ₃ 0-50%
La ₂ O ₃ 0-60%
Y ₂ O ₃ + La ₂ O ₃ 20-60%
TiO ₂ 0-10%
ZrO ₂ 0-10%
The rubber reinforcing cord according to claim 1, comprising:   The rubber reinforcing cord according to claim 1, wherein the glass composition contains ZnO.   The rubber reinforcing cord according to claim 1, wherein the glass composition contains at least one selected from MgO, CaO, SrO, and BaO.   The rubber reinforcing cord according to claim 6, wherein the glass composition contains at least two kinds selected from MgO, CaO, SrO and BaO. The rubber reinforcing cord according to claim 1, wherein the glass composition contains B ₂ O ₃ . The cord for reinforcing rubber according to claim 1, wherein the total content of Y ₂ O ₃ and La ₂ O ₃ in the glass composition is 36% by weight or less.   The rubber reinforcing cord according to claim 1, wherein the filament has a diameter of 3 to 11 µm.   The rubber reinforcing cord according to claim 1, wherein the strand includes 100 to 2000 filaments.   The cord for rubber reinforcement according to claim 11, which has a structure in which two or more strands are bundled. The bundle of two or more strands includes a total of 200 to 5000 filaments;
The rubber reinforcing cord according to claim 12, wherein a wire diameter in the bundled state is 50 to 150 tex. The strand is coated with a first coating layer;
The said 1st coating layer is a layer formed by apply | coating to the said strand the process liquid containing at least 1 sort (s) chosen from a resorcinol-formaldehyde condensate and a vulcanizing agent, and a latex. Rubber reinforcement cord.   The latex according to claim 14, wherein the latex is at least one selected from vinylpyridine-styrene-butadiene terpolymer latex, chlorosulfonated polyethylene latex, acrylonitrile-butadiene copolymer latex, and nitrile group-containing highly saturated polymer latex. Cord for rubber reinforcement.   The rubber reinforcing cord according to claim 14, wherein the vulcanizing agent is at least one selected from a maleimide compound and an organic diisocyanate compound.   The cord for rubber reinforcement according to claim 14, which has a structure in which two or more yarns formed by twisting strands covered with the first coating layer are bundled and further twisted.   The rubber reinforcing cord according to claim 1, wherein the rubber reinforcing cord is covered with a second covering layer containing rubber. The rubber reinforcing cord according to claim 1 is provided,
A rubber belt having a structure in which the rubber reinforcing cord is embedded in a matrix rubber having a predetermined shape.   The rubber belt according to claim 19, which is a timing belt.

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