Rubber reinforcing cords and rubber products using them

Abstract

Rubber reinforcing cord suitable for improving flexural fatigue resistance and rubber using the same We provide products. [Solution] The rubber reinforcing cord 10 consists of a carbon fiber strand 11 and a glass fiber strand It is equipped with a glass fiber strand 12. The glass fiber strand 12 is arranged around the carbon fiber strand 11. Several are arranged. Cross-sectional view of the rubber reinforcing cord 10, the glass fiber strand 12 The coverage rate of the carbon fiber strand 11 is 80% or more.

Description

Technical Field

[0001] The present disclosure relates to a rubber reinforcing cord and a rubber product using the same.

Background Art

[0002] Rubber products such as rubber belts and tires are repeatedly subjected to bending stress. Such rubber As a reinforcing material for products, rubber reinforcing cords formed using fibers are widely used. Patent Document 1 uses a carbon fiber strand in the core portion, and in the skin portion around the core portion discloses a rubber reinforcing cord using a plurality of glass fiber strands.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to studies by the present inventors, there is room for improvement in the bending fatigue resistance of rubber reinforcing cords.

[0005] The present disclosure aims to provide a rubber reinforcing cord suitable for improving bending fatigue resistance and a rubber product using the same. The purpose is to provide the rubber product.

Means for Solving the Problems

[0006] The present disclosure relates to a rubber reinforcing cord for reinforcing rubber products, the rubber reinforcing cord includes a carbon fiber strand, and a plurality of glass fiber strands arranged around the carbon fiber strand. Equipped with, In a cross-sectional view of the rubber reinforcing cord, the carbon fiber is formed by the plurality of glass fiber strands. The fiber strand coverage rate is 80% or more. We provide rubber reinforcement cords. [Effects of the Invention]

[0007] According to this disclosure, a rubber reinforcing cord suitable for improving flexural fatigue resistance and We can provide the rubber products used. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing an example of a rubber reinforcing cord according to the first embodiment of this disclosure. [Figure 2] This is a cross-sectional view showing another example of a rubber reinforcing cord according to the first embodiment of this disclosure. [Figure 3] This is a cross-sectional view showing yet another example of a rubber reinforcing cord according to the first embodiment of this disclosure. [Figure 4] This is a schematic perspective view showing an example of a rubber product according to the second embodiment of this disclosure. [Figure 5] This figure schematically illustrates the method of bending tests performed on the rubber reinforcing cords of the examples and comparative examples. [Figure 6] This graph shows the relationship between the number of bends and tensile strength when flat belts using rubber-reinforced cords according to the examples and comparative examples are subjected to bending tests. [Figure 7] This graph shows the relationship between the number of bends and the strength retention rate when flat belts using rubber-reinforced cords according to the examples and comparative examples are subjected to bending tests. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described below with reference to the drawings. The following description is based on the disclosure This is just one example, and this disclosure is not limited to the embodiments described below. The upper and lower limits of a numerical range described can be arbitrarily combined in both the case where the upper limit and the lower limit are described individually, and the case where the upper limit and the lower limit are described as a range. The upper and lower limits of a numerical range described can be arbitrarily combined in both the case where the upper limit and the lower limit are described individually, and the case where the upper limit and the lower limit are described as a range.

[0010] (First Embodiment) Figure 1 shows an example of the rubber reinforcing cord 10 according to the first embodiment of the present disclosure. The rubber reinforcing cord 10 includes a carbon fiber strand 11 and a glass fiber strand 12. A plurality of the glass fiber strands 12 are arranged around the carbon fiber strand 11. In a cross-sectional view of the rubber reinforcing cord 10, the coverage of the carbon fiber strand 11 by the glass fiber strands 12 is 80% or more.

[0011] Note that in the present specification, "the coverage of the carbon fiber strand 11 by the glass fiber strands 12 (hereinafter simply referred to as "coverage R")" is defined such that, in a cross-sectional view of the rubber reinforcing cord 10, the total length of the entire outer periphery 15 of the carbon fiber strand 11 is defined as Dt, and the total length of the outer peripheral portion 16 of the carbon fiber strand 11 that is not covered by the glass fiber strands 12 is defined as Db, the coverage can be calculated from the following formula (1). When Db is defined as above, the coverage can be calculated from the following formula (1). R=(Dt-Db) / Dt×100 [%] (1)

[0012] The cross-sectional view of the rubber reinforcing cord 10 can be obtained, for example, by exposing the cross section of the rubber reinforcing cord 10 using a cutting tool such as a cutter or a grinding tool such as a grinder, exposing the cross section of the rubber reinforcing cord 10 using a cutting tool such as a cutter or a grinding tool such as a grinder, and observing the exposed cross section of the rubber reinforcing cord 10 with a scanning electron microscope. This can be done by observing the exposed cross section of the rubber reinforcing cord 10 with a scanning electron microscope.

[0013] The rubber reinforcing cord 10 of the present embodiment is suitable for improving flexural fatigue resistance.

[0014] The coverage rate R may be, for example, 85% or more, 90% or more, or even 95% or more. Furthermore, the coverage rate R may be 99% or more, approximately 100%, or 100%.

[0015] The diameter of the rubber reinforcing cord 10 is not particularly limited. For example, 0.5mm to 5mm, 0.5mm to 3mm, 1.0mm to 2mm, and furthermore... 1.2mm to 1.8mm is also acceptable.

[0016] The diameter of the rubber reinforcement cord 10 can be measured, for example, with a dial thickness gauge.

[0017] The gauge (linear density) of the rubber reinforcing cord 10 is not particularly limited. The thread count ranges from, for example, 200 tex to 20000 tex, and from 600 tex to 10000 tex. For example, 1000 tex to 6000 tex, and even 1500 tex to 2500 tex. That's fine.

[0018] The carbon fiber strand 11 consists of a bundle of carbon fiber filaments 11a and carbon fiber filaments. It may also include a first coating 11b that covers at least a portion of the surface of the bundle 11a. The fiber strand 12 consists of a bundle of glass fiber filaments 12a and glass fiber filaments. The bundle may also include a second coating 12b that covers at least a portion of the surface of the bundle 12a.

[0019] In this specification, "carbon fiber strand" refers to a bundle of carbon fiber filaments. This means that the filament being made contains carbon fiber filament as its main component. "Containing fiber filaments as the main component" means that the cross-sectional area of ​​the carbon fiber filament bundle is... This means that the filament with the largest proportion is carbon fiber filament. The filament bundle may consist substantially of carbon fiber filaments. "The filament bundle consists substantially of carbon fiber filaments" means that the carbon fiber filament bundle This means that the proportion of carbon fiber filaments in the cross-sectional area is 90% or more. The ratio may be 95% or more, and may even be 99% or more. Carbon fiber filler The ment bundle may consist solely of carbon fiber filaments.

[0020] Furthermore, in this specification, "glass fiber strand" refers to a bundle of glass fiber filaments. This means that the filaments that make up the structure primarily consist of glass fiber filaments. "Containing glass fiber filaments as the main component" refers to the cross-section of a bundle of glass fiber filaments. This means that the filament that makes up the largest proportion of the product is the glass fiber filament. A bundle of glass fiber filaments may consist substantially of glass fiber filaments. i. "A bundle of glass fiber filaments consists substantially of glass fiber filaments" means that The proportion of glass fiber filaments to the cross-sectional area of ​​the lath fiber filament bundle is 90% or more. This means that the percentage may be 95% or higher, and even 99% or higher. It is also possible that the glass fiber filament bundle is composed solely of glass fiber filaments. That's fine.

[0021] The rubber reinforcing cord 10 according to this embodiment will be described in more detail below.

[0022] (Carbon fiber strands) The straight filaments contained in the carbon fiber filament bundle 11a of the carbon fiber strand 11 The diameter is, for example, 4 μm to 10 μm, and may also be 5 μm to 9 μm.

[0023] The number of carbon fiber filaments contained in one carbon fiber filament bundle 11a is not particularly limited. Not determined. The number of carbon fiber filaments contained in one carbon fiber filament bundle 11a. For example, this ranges from 1,000 to 80,000, 2,500 to 50,000, and 6,000 to... 40,000, 6,000-25,000, and even 10,000-15,000 That's fine.

[0024] The thread count (linear density) of the carbon fiber filament bundle 11a is not particularly limited. The thread count of the lament bundle 11a is, for example, 60 tex to 8000 tex, and 180 tex to 3500 tex, 300 tex to 2000 tex, and even 600 tex to 1000 tex x is also acceptable.

[0025] The carbon fiber filament bundle 11a may or may not be twisted. There is no limit to the number of carbon fiber filament bundles 11a; there may be one or multiple bundles. It is also possible. The carbon fiber filament bundle 11a is made by bundling multiple carbon fiber filament bundles together. This may also be the case. In this case, in each of the multiple carbon fiber filament bundles, The raw fiber filament may or may not be pre-twisted. Each carbon fiber filament bundle 11a may or may not be top-twisted. The number of undertwists and the number of overtwists of the carbon fiber filament bundle 11a may be, for example, 5. The number of strokes per 25mm is 0.0 or less, and may also be 2.5 strokes per 25mm or less.

[0026] The surface of the carbon fiber filaments contained in the carbon fiber filament bundle 11a has adhesive strength Pretreatment may be performed to enhance the effect. A preferred example of a pretreatment agent is epoxy group and A compound containing at least one functional group selected from the group consisting of mino groups. Examples of pretreatment agents include aminosilane, epoxysilane, novolac-type epoxy resin, and bis. Phenol A type epoxy resin, bisphenol F type epoxy resin, brominated epoxy resin, This includes bisphenol AD ​​type epoxy resins and glycidylamine type epoxy resins. Specific examples include Nagase ChemteX's Denacol series and DIC's Epiclo. Examples include the N series and Mitsubishi Chemical's Epicote series. Also, as a pretreatment agent. Polyurethane resins and isocyanate compounds can also be used in the same way. For example, a pretreatment agent and Then, selected from the group consisting of epoxy resins, urethane resins, and isocyanate compounds. A treatment agent containing at least one of the following may be used. Pretreatment using such a treatment agent By doing so, epoxy is formed between the carbon fiber filament bundle 11a and the first coating 11b. At least one selected from the group consisting of resins, urethane resins, and isocyanate compounds A resin layer containing one of the following is further provided. Carbon fiber filament bundle 11a contains carbon fiber filament This includes other fiber filaments besides filaments (e.g., glass fiber filaments). In that case, the surface of the fiber filament is also subjected to the pretreatment described above to increase adhesive strength. It is preferable that it is done.

[0027] The first coating 11b covers at least a portion of the surface of the carbon fiber filament bundle 11a. It can be provided in such a way. The first coating 11b is on the surface of the carbon fiber filament bundle 11a. It may be provided directly, or in another layer (for example, the pretreatment of the carbon fiber filament as described above). A coating (for example, the resin layer) formed by the carbon fiber filament bundle 11 It may cover the surface of a.

[0028] The first coating 11b is applied to at least a portion of the surface of the carbon fiber filament bundle 11a, as described below. A first coating-forming treatment agent is supplied and dried by heat treatment to form It is possible. The supply of the first coating agent to the surface of the carbon fiber filament bundle 11a is For example, impregnate the carbon fiber filament bundle 11a with a first coating agent, or A first coating agent is applied to at least a portion of the surface of the carbon fiber filament bundle 11a. This can be done by the following: Furthermore, the heat treatment at this time will result in the carbon fiber filament bundle The moisture contained in 11a itself and the solvent of the treatment agent (e.g., water) are almost completely removed.

[0029] The first coating 11b may contain a rubber component. The rubber component may be nitrile rubber, hydrogen Nitrile rubber, carboxyl-modified nitrile rubber, and carboxyl-modified water Preferably, it contains at least one selected from the group consisting of nitrile rubber. The coating 11b may contain only one type of rubber as a rubber component, or it may contain multiple types. In this specification, unless otherwise specified, the term "nitrile rubber" refers to water Nitrile rubber that has not undergone carboxylation or carboxylation modification (acrylonitrile-butadiene) It means polymer rubber.

[0030] The first coating 11b may contain other rubbers in addition to the rubber described above. This includes butadiene-styrene copolymer, dicarboxylated butadiene-styrene copolymer, Vinylpyridine-butadiene-styrene copolymer, chloroprene rubber, butadiene rubber, Examples include chlorosulfonated polyethylene.

[0031] The first coating 11b may further contain a crosslinking agent. By including it, the adhesion of the carbon fiber strands 11 can be improved. An example of a crosslinking agent is P- Quinone dioxime-based crosslinking agents such as quinone dioxime, lauryl methacrylate and methyl Methacrylate crosslinking agents such as lumethaacrylate, DAF (diallyl fumarate), DAP (diallyl phthalate), TAC (triallyl cyanurate), and TAIC (triallyl cyanurate) Allyl crosslinking agents such as allyl isocyanurate, bismaleimide, and phenylmaleimide. and maleimide-based crosslinking agents such as N,N'-m-phenylenedimaleimide, aromatics or fats. Organic diisocyanates, polyisocyanates, blocked isocyanates, and block Isocyanate compounds such as cyclopolyisocyanates, aromatic nitroso compounds, sulfur, These also include peroxides. These crosslinking agents may be used individually or in combination. These may be used in combination. These crosslinking agents depend on the type of rubber contained in the first coating 11b, and The type of other component that comes into contact with the carbon fiber strand 11 may be selected considering these factors. These crosslinking agents, when used in the form of a dispersion, are homogeneously present in the first coating agent. It can exist.

[0032] The crosslinking agent is selected from the group consisting of maleimide-based crosslinking agents and isocyanate compounds. It may contain at least one of them. Among maleimide crosslinking agents, 4,4'-bismaleimide Dodiphenylmethane has good stability when dispersed in water, high crosslinking effect, and resistance after crosslinking. Because it is highly thermal, it is suitable for use. Examples of isocyanate compounds include block Isocyanates are used. Maleimide crosslinking agents and isocyanate compounds are each By combining it with rubber latex, the reinforcing cord and matrix rubber Adhesion can be specifically enhanced. In particular, carboxyl-modified hydrogenated nitrile The combination of latex and maleimide-based crosslinking agents can further enhance adhesion. ru.

[0033] The first coating 11b may further contain a filler. Examples of fillers include carbon fiber. Fine particles of covalent compounds such as lac and silica, fine particles of sparingly soluble salts, and fine particles of metal oxides. These include fine particles of metal hydroxides and fine particles of complex metal oxide salts such as talc. Among these, at least one selected from the group consisting of carbon black and silica is preferred. stomach.

[0034] The average particle size of carbon black is, for example, 5nm to 300nm, and 100nm to 20 The average particle size of silica can be 0 nm, or even 130 nm to 170 nm. It is 5nm to 200nm, 7nm to 100nm, and even 7nm to 30nm. Here, the average particle size is the particle size measured using a transmission electron microscope for 50 or more particles. It is determined by dividing the total particle size by the number of particles measured. Note that if the particles are not spherical... For this, the particle size is defined as the average of the longest and shortest diameters of each particle.

[0035] The filler, by being dispersed within the rubber, enhances the properties of the coating, such as its tensile strength and peel strength. It has the effect of improving. In addition to these effects, the filler fills the space between the fibers and the coating, and the coating By increasing the cohesive force of the adhesive components between the film and the matrix rubber, the adhesive strength is enhanced. It also has the effect of improving [something].

[0036] The first coating 11b preferably does not contain resorcinol-formaldehyde condensates. In that case, when preparing the first coating 11b, formaldehyde and ammonia, etc. Because it eliminates the need to use environmentally harmful substances, environmental measures for workers become unnecessary. Yes.

[0037] The first coating 11b contains rubber components and crosslinking agents, as well as fillers and other components (for example) If, the above-mentioned filler further contains metal oxides other than the metal oxides added, or resins, etc. You can stay like that.

[0038] The content of rubber components and crosslinking agents in the first coating 11b is not particularly limited. The rubber component content in the coating 11b is, for example, 50% by mass to 90% by mass or less. Furthermore, the crosslinking agent content in the first coating 11b is, for example, 10% to 50% by mass or less. That is the case.

[0039] The first coating agent is nitrile rubber, hydrogenated nitrile rubber, carboxyl From the group consisting of modified nitrile rubber and carboxyl-modified hydrogenated nitrile rubber The first coating agent is a rubber latex selected from among the first coating agents. This may include only one type of rubber latex, or multiple types of rubber latex. It may include several types.

[0040] The first coating agent contains other rubber latex in addition to the above-mentioned rubber latex. But that is also acceptable. Other examples of rubber latex include butadiene-styrene copolymer latex, di Carboxylated butadiene / styrene copolymer latex, vinylpyridine / butadiene Styrene terpolymer latex, chloroprene latex, butadiene latex, It contains chlorosulfonated polyethylene latex. The first coating agent is this These rubber latexes may contain multiple types.

[0041] The first coating-forming treatment agent may further contain a crosslinking agent. An example of a crosslinking agent contained in the agent is the example described above as a crosslinking agent contained in the first coating 11b. The same applies. Furthermore, the crosslinking agent is used in the form of a dispersion, as is the first coating-forming treatment agent. This is preferable for ensuring a homogeneous distribution within the material.

[0042] The first coating agent may further contain a filler. An example of a filler included in the agent is the example described above as a filler included in the first coating 11b. It is similar to that.

[0043] The first coating agent preferably does not contain resorcinol-formaldehyde condensate. It seems so.

[0044] The first coating agent includes rubber latex and a crosslinking agent, as well as fillers and other materials. It may also contain the following components. For example, the first coating agent may be a resin, a plasticizer, or an anti-aging agent. It contains agents, stabilizers, and metal oxides other than the metal oxides added as fillers mentioned above. This is also acceptable. However, the first coating agent may be one that does not contain resin.

[0045] The ratio of the mass of the first coating 11b to the mass of the carbon fiber filament bundle 11a (hereinafter, The adhesion rate of the first coating 11b (referred to as "adhesion rate of the first coating 11b") is not particularly limited and can be adjusted as appropriate. The adhesion rate of the coating 11b is, for example, 5% to 35%, 10% to 30%, and even 15% to It may be 25%. The effect of suppressing and protecting the fraying of the carbon fiber strands 11 is sufficient. If desired, the adhesion rate of the first coating 11b is preferably 5% or more. If you want to obtain a moderate modulus of elasticity while ensuring sufficient dimensional stability of strand 11, the first coating The adhesion rate of 11b is preferably 35% or less.

[0046] In order to improve the adhesion of the carbon fiber strands 11, an additional coating is applied to the first coating 11b. A coating may be further provided. The treatment agent for forming the additional coating is the first coating-forming treatment agent. The physicochemical agent may be the same as or different from the first coating treatment. For example, the components or solvent may be the same as the first coating treatment. An additional coating may be formed with a treatment agent different from the agent. Adhesion of carbon fiber strand 11 To further improve this, an additional coating can be applied on top of the existing coating.

[0047] (Glass fiber strand) Filaments contained in the glass fiber filament bundle 12a of the glass fiber strand 12 The diameter is, for example, 4 μm to 12 μm, and may also be 6 μm to 10 μm.

[0048] The number of glass fiber filaments contained in one glass fiber filament bundle 12a is, Not limited to, the glass fiber filaments contained in one glass fiber filament bundle 12a The number of points can range from 100 to 5000, or from 200 to 3000. The range can be between 300 and 2000, or even between 500 and 1500.

[0049] The thread count (linear density) of the glass fiber filament bundle 12a is not particularly limited. The thread count of filament bundle 12a is, for example, 20 tex to 350 tex, and 40 tex to Even with 210 tex, 60 tex to 150 tex, and even 60 tex to 80 tex good.

[0050] The glass fiber filament bundle 12a may be untwisted or untwisted. This is also good. The glass fiber filaments contained in the glass fiber filament bundle 12a are under-twisted. If so, the number of undertwists in the glass fiber strand 12 is, for example, 0.5 times / 25mm~ It is 4.0 times / 25mm, 1.0 time / 25mm to 3.5 times / 25mm, and even 1.5 The length may be 25mm / cycle to 2.5 times / 25mm. The glass fiber filament bundle 12a is The fiber may be twisted or not. Glass fiber filament bundle 12 If a is top-twisted, the number of top twists in the glass fiber filament bundle 12a is, for example, 0 It is 0.1 time / 25mm to 3.0 times / 25mm, and 0.5 times / 25mm to 3.0 times / 25mm m, or even 1.0 time / 25mm to 2.0 times / 25mm.

[0051] When the glass fiber filament bundle 12a is under-twisted and over-twisted, the glass fiber The twisting method of the lament bundle 12a may be the same Lang twist in both the lower twisting direction and the upper twisting direction. It may also be a double twist where the lower twist direction and upper twist direction are in opposite directions. There are no restrictions on the direction of twisting, such as S-shaped twisting. It could be in the direction of Z, or it could be in the Z direction.

[0052] The surface of the glass fiber filaments contained in the glass fiber filament bundle 12a has strong adhesive properties. Pretreatment may be performed to increase the degree. An example of a pretreatment agent is a carbon fiber filament bundle 1 This is similar to the above example concerning the carbon fiber filament of 1a.

[0053] The second coating 12b covers at least a portion of the surface of the glass fiber filament bundle 12a. It can be provided in this manner. The second coating 12b is on the surface of the glass fiber filament bundle 12a. It may be provided directly on the surface, or on another layer (for example, the glass fiber filament mentioned above) Glass fibers through a coating (e.g., the resin layer mentioned above) similar to the coating formed by the pretreatment process. It may cover the surface of the fibrous bundle 12a.

[0054] Examples of materials constituting the second coating 12b and the second coating-forming treatment agent are given for the first coating 11 The materials constituting b and the first coating agent are the same as in the examples described above.

[0055] The ratio of the mass of the second coating 12b to the mass of the glass fiber filament bundle 12a (hereinafter, The "adhesion rate of the second coating 12b" is not particularly limited and can be adjusted as appropriate. The adhesion rate of the coating 12b is, for example, 5% to 35%, 10% to 30%, and even 15%. It may be up to 25%. The effect of suppressing and protecting the fraying of the glass fiber strand 12 is sufficient. If you want to obtain it in minutes, it is preferable that the adhesion rate of the second coating 12b is 5% or more. If you want to obtain a moderate modulus of elasticity while ensuring sufficient dimensional stability of the lath fiber strand 12, The adhesion rate of the coating 12b in step 2 is preferably 35% or less.

[0056] In order to improve the adhesion of the glass fiber strand 12, an additional coating is applied to the second coating 12b. A further coating may be provided. The treatment agent for forming the additional coating is a second coating agent. The treatment agent may be the same as or different from the second coating agent. For example, the components or solvent may be the second coating agent. An additional coating may be formed using a treatment agent different from the priming agent. To further improve adhesion, an additional coating can be applied on top of the existing coating.

[0057] (Relationship between carbon fiber strands and glass fiber strands) The sum of the total cross-sectional area of ​​the carbon fiber strand 11 and the total cross-sectional area of ​​the glass fiber strand 12. The ratio of the total cross-sectional area of ​​carbon fiber strand 11 to the product (hereinafter simply referred to as "carbon fiber strand 1") The ratio of the cross-sectional area of ​​the rubber compound (referred to as "1") is preferably in the range of 20% to 80%. If sufficient flexibility is to be obtained for the reinforcing cord 20, the cross-sectional area ratio of the carbon fiber strand 11 is Preferably, it should be 80% or less, 70% or less, 65% or less, 60% or less, or 55% or less. Furthermore, it may be 50% or less. High tensile strength and excellent If sufficient dimensional stability is desired, the cross-sectional area ratio of the carbon fiber strand 11 should be 20% Preferably, the percentage is 25% or more, 30% or more, 35% or more, and even 40% or more. That's fine.

[0058] From the perspective of rubber products using the rubber reinforcing cord 10, per diameter of the rubber reinforcing cord 10 It is preferable that the tensile strength and tensile modulus of the carbon fiber strand 11 are high. A high cross-sectional area ratio is preferable. On the other hand, multiple glass fiber strands 12 are connected to carbon fiber strands. When arranged around land 11, the cross-sectional area ratio of glass fiber strands 12 increases. Therefore, it is difficult to increase the cross-sectional area ratio of the carbon fiber strands 11.

[0059] The number of carbon fiber strands 11 and the number of glass fiber strands 12 are the same as the number of rubber reinforcement cords. The properties required for 10, and the properties of the carbon fiber strand 11 and the glass fiber strand 12. Can be selected according to: [Number of carbon fiber strands] / [Number of glass fiber strands] Preferred examples of the ratio of the number of do include [1] / [3~30], [2] / [6~30], and [3] / [10~40] are examples.

[0060] As shown in Figures 2 and 3, a third coating 1 is applied around multiple glass fiber strands 12. 3 may be provided. An example of the material constituting the third coating 13 is the first coating 11b This is similar to the example above regarding the constituent materials.

[0061] As shown in Figure 2 for the rubber reinforcing cord 20 and in Figure 3 for the rubber reinforcing cord 30, the third The coating 13 is in contact with multiple glass fiber strands 11. It may be provided around 2. An example of such a configuration is multiple glass fiber strands One option is to sparsely arrange 12 around the carbon fiber strand 11. In this case, the third This makes it easier for the coating agent to penetrate from the outside to the inside of the glass fiber strand 12. Therefore, the third coating 13 is on the surface of the carbon fiber strand 11 (i.e., the first coating 11b) It becomes more likely to form in contact with it.

[0062] The third coating 13 is made of multiple glass fiber strands so as not to come into contact with the carbon fiber strands 11. They may be provided around land 12. As an example of such a configuration, multiple glass fiber One option is to densely arrange the strands 12 around the carbon fiber strands 11. In addition, the third coating agent is applied to the outside of the glass fiber strand 12 (glass fiber strand (towards 12, the carbon fiber strand 11 and the opposite side) from the inside (towards the glass fiber strand 12) In contrast, by making it difficult for carbon fiber strands 11 to penetrate the carbon fiber strands 11, the third coating 13 is made less permeable to carbon fiber. Formed to be in contact with the surface of the fiber strand 11 (i.e., the first coating 11b) It becomes harder. Furthermore, multiple glass fiber strands 12 are densely packed around the carbon fiber strands 11. Placing it in this way allows the third coating 13 to enter through the gap between adjacent glass fiber strands 12. To the extent that it does not get stuck, multiple glass fibers are used to reduce the gaps between the glass fiber strands 12. The arrangement of glass fiber strands 12, and the gaps between adjacent glass fiber strands 12. This includes arranging multiple glass fiber strands 12 so as not to leave any gaps.

[0063] Third coating on the total mass of carbon fiber strands 11 and glass fiber strands 12 The ratio of the masses of the 13 (hereinafter referred to as the "adhesion rate of the third coating 13") can be adjusted as appropriate. The adhesion rate of the coating 13 in 3 is, for example, 1% to 10%, 1% to 5%, and even 2% to 5%. That's fine.

[0064] With respect to the total mass of carbon fiber filament 11a and glass fiber filament 21a, The ratio of the total mass of the first coating 11b, the second coating 12b, and the third coating 13 (hereinafter referred to as "coating") The "total film adhesion rate" can be adjusted as appropriate. For example, the total film adhesion rate can range from 1% to 40%. And it may be 5% to 30%, 10% to 30%, or even 20% to 25%.

[0065] (Second Embodiment) The second embodiment is described below. Matters described in the first embodiment may be omitted as appropriate. It will be abbreviated.

[0066] Figure 4 shows an example of a rubber product 40 according to the second embodiment of this disclosure. Rubber product 40 It comprises a matrix rubber 41 and a rubber reinforcing cord 42. This is a rubber reinforcing cord of the first embodiment. The rubber product 40 of this embodiment is the first embodiment Because it is equipped with rubber reinforcement cords, it can have high resistance to bending fatigue.

[0067] The rubber product 40 is not particularly limited. Examples of rubber products in this embodiment include automobiles and bicycles. This includes tires and rubber belts such as power transmission belts. Examples of power transmission belts include meshing belts. This includes interlocking power transmission belts and friction power transmission belts. An example of interlocking power transmission belts is used in automobiles. This includes toothed belts, such as timing belts. Examples of friction transmission belts include: This includes flat belts, round belts, V-belts, V-ribbed belts, etc. That is, this embodiment These rubber products include toothed belts, flat belts, round belts, V-belts, or V-ribbed belts. That's fine.

[0068] The rubber product 40 of this embodiment uses the rubber reinforcing cord 42 of this embodiment as a matrix rubber Formed by embedding in 41. Rubber reinforcing cord 42 is embedded in the matrix rubber. The method of embedding within 41 is not particularly limited, and known methods may be applied. Product 40 (for example, a rubber belt) has a rubber reinforcing cord 42 embedded in it, It may have high bending fatigue resistance. Therefore, the rubber product 40 is suitable for rear-wheel drive vehicles. High-quality products such as engine timing belts, auxiliary drive belts for vehicles, and belts for large industrial equipment. It is particularly suitable for applications requiring high elastic modulus and strength.

[0069] The matrix rubber 41 used in the rubber product 40 of this embodiment is not particularly limited, and Loloprene rubber, chlorosulfonated polyethylene rubber, ethylene propylene rubber, hydrogenated Nitrile rubber may also be used. Hydrogenated nitrile rubber is a zinc acrylate derivative (for example For example, hydrogenated nitrile rubber in which zinc methacrylate is dispersed. At least one selected from hydrogenated nitrile rubber in which rubber and zinc acrylate derivatives are dispersed. Another rubber is preferred from the viewpoint of water resistance and oil resistance. The matrix rubber 41 is It may also contain ruboxyl-modified hydrogenated nitrile rubber. Note: Rubber reinforcement code 10 The coating (for example, the third coating 13) and the matrix rubber 41 of the rubber product 40 are of the same type. It is preferable, in terms of adhesion, that the material contains rubber or consists of the same type of rubber.

[0070] Figure 4 shows a toothed belt as an example of rubber product 40. The toothed belt shown in Figure 4 It consists of a belt body 41a and multiple protruding from the belt body 41a at regular intervals in a predetermined direction. It is equipped with teeth 41b. The rubber reinforcing cord 42 is located inside the belt body 41a. It is embedded parallel to the longitudinal direction of the main body 41a of the belt.

[0071] As described above, this specification discloses the following technologies.

[0072] (First technology) A rubber reinforcing cord for reinforcing rubber products, The aforementioned rubber reinforcing cord is Carbon fiber strands and Multiple glass fiber strands arranged around the carbon fiber strand, Equipped with, In a cross-sectional view of the rubber reinforcing cord, the carbon fiber is formed by the plurality of glass fiber strands. The fiber strand coverage rate is 80% or more. Rubber reinforcement cord.

[0073] (Second technology) The carbon fiber strands are A bundle of carbon fiber filaments, A first coating covering at least a portion of the surface of the carbon fiber filament bundle, Equipped with, Rubber reinforcing cord as described in Technical 1.

[0074] (Third technology) The carbon fiber filament bundle is untwisted. Rubber reinforcing cord as described in Technical 2.

[0075] (The fourth technology) Each fiberglass strand is A bundle of glass fiber filaments, A second coating covering at least a portion of the surface of the glass fiber filament bundle, Equipped with, A rubber reinforcing cord as described in one of the following technologies (1-3).

[0076] (The fifth technology) Each glass fiber filament bundle is placed in the range of 0.5 turns / 25mm to 4.0 turns / 25mm. The carbon fiber strands are twisted, and around them, 0.1 turns / 25 mm ~ 3.0 The top is twisted in a range of 25mm per turn. Rubber reinforcing cord as described in Technical 4.

[0077] (The sixth technology) Each bundle of glass fiber filaments is twisted using the Lang twist method. Rubber reinforcing cord as described in Technical 5.

[0078] (The seventh technology) Around the plurality of glass fiber strands, so as to be in contact with the carbon fiber strands, A third coating is provided, A rubber reinforcing cord as described in one of the following technologies 1-6.

[0079] (The 8th technique) Around the plurality of glass fiber strands, so as not to come into contact with the carbon fiber strands , comprising a third coating, A rubber reinforcing cord as described in one of the following technologies 1-6.

[0080] (The 9th technology) Matrix rubber and A rubber reinforcing cord described in one of the techniques 1-8, Rubber products equipped with these features.

[0081] (The 10th technology) The aforementioned rubber reinforcing cord is embedded in the matrix rubber. Rubber products as described in Technical 9.

[0082] (The 11th technology) The aforementioned rubber product is a rubber belt. A rubber product as described in either Technology 9 or 10. [Examples]

[0083] The embodiments of this disclosure will be described in more detail below with reference to examples and comparative examples.

[0084] [Manufacturing of rubber reinforcement cords] (Example 1) As a carbon fiber filament bundle, Toray's "T700SC-12000" (carbon fiber filament Average diameter of filaments: 7 μm, Number of carbon fiber filaments: 12,000 (untwisted), No. A bundle of carbon fiber filaments (700tex) was prepared. The following composition was added to this bundle of carbon fiber filaments as shown in Table 1. The primary treatment solution (first coating agent) was applied and dried. In this way, carbon A carbon fiber strand was obtained in which a first coating was formed on the surface of the fiber filament bundle. When applying the chemical solution, the ratio of the mass of the first coating to the mass of the carbon fiber filament bundle is Therefore, the amount of primary treatment solution applied was adjusted with a target value of 20%.

[0085] [Table 1]

[0086] The abbreviations used in Table 1 are as follows: HNBR: Hydrogenated nitrile rubber latex (Zetpol 2230LX, manufactured by Zeon Corporation) BMI: Bismaleimide aqueous dispersion (40% solids by mass) NCO: Blocked isocyanate (Elastron BN-27, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Si: Water-dispersible colloidal silica (Nissan Chemical Industries, Ltd. "Snowtex ST-S")

[0087] In addition, as a bundle of glass fiber filaments, Nippon Sheet Glass Co., Ltd.'s "K Glass Filament" ( Prepare a filament bundle consisting of 200 filaments with an average diameter of 7 μm, and then use three of these filament bundles. We prepared a glass fiber that had been under-twisted 2.0 times / 25mm using a Z-twist. The same primary treatment used to form the first coating on the carbon fiber filament bundle is applied to the surface of the lament bundle. A second coating is formed using a sizing solution (second coating-forming treatment agent) on the glass fiber strand. The following was obtained. When applying the primary treatment solution, the first treatment solution was applied to the mass of the glass fiber filament bundle. The amount of primary treatment solution applied was adjusted to achieve a target mass ratio of 20% for the film.

[0088] Next, 15 glass fiber strands are placed around one carbon fiber strand, Z The cord was obtained by adding an overtwist at a rate of 1.5 times / 25mm through twisting. In addition, a secondary treatment solution (third coating-forming treatment agent) (Road Corporation's "chemlok 233X By applying and drying the coating, a third coating was formed on the surface of the cord. Thus, a rubber reinforcing cord according to Example 1 was obtained. The thread count of the rubber reinforcing cord according to Example 1 is , was 2410tex. When applying the secondary treatment solution, the third coating relative to the mass of the code The amount of primary treatment solution applied was adjusted to achieve a target mass ratio of 4% for the film.

[0089] (Example 2) In the preparation of glass fiber strands, five filament bundles are twisted together to form glass fiber strands. The formation of the filament bundle and the fabrication of the cord involved the periphery of a single carbon fiber strand. The process is the same as in Example 1, except that nine glass fiber strands are arranged in a circle and then twisted upwards. The rubber reinforcement cord according to Example 2 was obtained using the method. The number of hands was 2377tex.

[0090] (Comparative Example 1) In the preparation of glass fiber strands, nine filament bundles are twisted together to form glass fiber strands. The formation of the filament bundle and the fabrication of the cord involved the periphery of a single carbon fiber strand. The process is the same as in Example 1, except that five glass fiber strands are arranged in a circle and then twisted upwards. The rubber reinforcement cord according to Comparative Example 1 was obtained using this method. The number of hands was 2411tex.

[0091] Table 2 shows the manufacturing conditions for the rubber reinforcing cords in the examples and comparative examples.

[0092] [Table 2]

[0093] The rubber reinforcing cords obtained in the examples and comparative examples were evaluated as follows.

[0094] [Observation using a scanning electron microscope] The rubber reinforcing cords of the examples and comparative examples were embedded in hydrogenated nitrile rubber and cut with a cutter. By cutting, the cross-section of the rubber reinforcing cord was exposed. A scanning electron microscope (SEM) was used. Then, the cross-section of the exposed rubber reinforcing cord was observed. During the SEM observation, glass The coverage ratio R of carbon fiber strands by fiber strands was calculated. Therefore, the cross-section of each rubber reinforcing cord was observed at 10 different locations along its length. The average of the coverage rates at 10 locations was defined as the coverage rate R. Furthermore, the cross-sectional area ratio of the carbon fiber strands was used. Measurements were also taken for the rubber reinforcing cords of Examples 1 and 2 and Comparative Example 1. Even then, a portion of the third coating was in contact with the first coating of the carbon fiber strand.

[0095] [Diameter measurement] Using a commonly used dial thickness gauge, the rubber of the examples and comparative examples was used. The diameter of the reinforcing cord was calculated. For the calculation of the diameter of each rubber reinforcing cord... The diameter was measured at five different locations along the length, and the average of the five diameters was used for rubber reinforcement. The diameter of the rubber band was used.

[0096] [Adhesion test] First, a rubber piece made of hydrogenated nitrile rubber (25mm wide x 50mm long x 5mm thick) Two pieces were prepared. Next, the rubber reinforcement cord was made to be parallel to the longitudinal direction of the rubber piece. The example and comparative example rubber reinforcing cords were sandwiched between two pieces of rubber and heated at 150°C for 20 minutes. The specimens were then bonded together. The resulting specimens were then subjected to a tensile testing using a commonly used tensile testing machine. By pulling in one direction and observing the fractured surface under an optical microscope, a tensile test can be performed. The fracture mode of the test specimens was determined. In all test specimens, the matrix rubber fractured. It was broken (hereinafter, this destruction mode will be referred to as "rubber destruction").

[0097] [Flexion fatigue resistance] The rubber reinforcing cords of the examples and comparative examples are made of a matrix made of hydrogenated nitrile rubber. It was embedded in the material to form a flat belt with a width of 10 mm, a length of 300 mm, and a thickness of 3 mm. The flat belt underwent bending tests, being bent 10,000 times, 20,000 times, and 50,000 times, respectively. The bending test was performed using the bending tester M shown in Figure 5.

[0098] The bending test machine M in Figure 5 consists of a motor M1, a bending jig M2, and a guide pulley P1 (diameter 10 It is equipped with (mm). In addition to guide pulley P1, guide pulleys P2 and P3 (any A diameter of 10 mm is provided inside the bending jig M2. First, the fabricated flat belt S is bent. A flat belt S is placed on guide pulleys P2 and P3 inside the bending jig M2 and connected via a connector (not shown). Connect the cord grip (not shown) at one end to the fixed end, and connect the flat bell via a connector (not shown). The other end of belt S, the cord grip (not shown), was connected to the weight W. The connector that connects them was placed on the guide pulley P1. Then, the motor M1 was activated, as shown in Figure 5. By reciprocating the bending jig M2 in the direction shown, the guide pulleys P2 and P3 In this process, a flat belt S was repeatedly bent. The bending test was performed at room temperature. After performing a bending test on belt S, the tensile strength of the flat belt S was measured. The weight W was 2k The value was g. The reciprocating motion of the bending jig M2 was performed at a frequency of 40 Hz.

[0099] [Tensile test] The tensile strength of the flat belts in the examples and comparative examples was measured before and after the bending test. Here, tensile strength is measured using a commonly used tensile testing machine and a commonly used codeg A tensile test was conducted using the lip, and the fracture strength (unit: N / code) obtained at that time was used. Yes, it exists. The tensile strength test was conducted under the conditions of a tensile speed of 300 mm / min and a gripping distance of 250 mm.

[0100] From the results of the bending test, the tensile strength of the flat belt before the bending test is set to 100%, and the bending strength is... The percentage of the tensile strength of the flat belt after testing (hereinafter referred to as the "strength retention rate") was calculated.

[0101] Rubber reinforcing cords of the examples and comparative examples, and flat belts made using them. The evaluation results are shown in Table 3. Furthermore, the tensile strength when the flat belt was repeatedly bent during the bending test is also shown. Figure 6 shows the change in tensile strength, and the strength when the flat belt is repeatedly bent in a bending test. Figure 7 shows the change in retention rate.

[0102] [Table 3] [Industrial applicability]

[0103] The rubber reinforcing cords of this disclosure are suitable for improving flexural fatigue resistance, and therefore various It is applicable to the reinforcement of rubber products. Furthermore, the rubber products of this disclosure have improved flexural fatigue resistance. It is suitable for various applications. [Explanation of symbols]

[0104] 10, 20, 30 Rubber reinforcement cords 11 Carbon fiber strands 11a Carbon fiber filament bundle 11b First coating 12 Fiberglass strands 12a Glass fiber filament bundle 12b Second coating 15 Outer circumference of carbon fiber strand 16 Outer periphery of carbon fiber strands not covered by glass fiber strands 40 Rubber Products 41 Matrix Rubber 42 Rubber reinforcement cord 41a Belt body 41b Teeth M Flexion Testing Machine M1 Motor M2 Bending Jig P1, P2, P3 guide pulleys S Flat Belt W weight

Claims

1. A rubber reinforcing cord for reinforcing rubber products, The aforementioned rubber reinforcing cord is Carbon fiber strands and Multiple glass fiber strands arranged around the carbon fiber strand, Equipped with, In a cross-sectional view of the rubber reinforcing cord, the carbon fiber is formed by the plurality of glass fiber strands. The fiber strand coverage rate is 80% or more. Rubber reinforcement cord.

2. The carbon fiber strands are A bundle of carbon fiber filaments, A first coating covering at least a portion of the surface of the carbon fiber filament bundle, Equipped with, The rubber reinforcing cord according to claim 1.

3. The carbon fiber filament bundle is untwisted. The rubber reinforcing cord according to claim 2.

4. Each fiberglass strand is A bundle of glass fiber filaments, A second coating covering at least a portion of the surface of the glass fiber filament bundle, Equipped with, The rubber reinforcing cord according to claim 1.

5. Each glass fiber filament bundle is placed in the range of 0.5 turns / 25 mm to 4.0 turns / 25 mm. The carbon fiber strands are twisted, and around them, 0.1 turns / 25 mm to 3.0 The top is twisted in a range of 25 turns / mm. The rubber reinforcing cord according to claim 4.

6. Each bundle of glass fiber filaments is twisted using the Lang twist method. The rubber reinforcing cord according to claim 5.

7. Around the plurality of glass fiber strands, so as to be in contact with the carbon fiber strands, A third coating is provided, The rubber reinforcing cord according to claim 1.

8. Around the plurality of glass fiber strands, so as not to come into contact with the carbon fiber strands , comprising a third coating, The rubber reinforcing cord according to claim 1.

9. Matrix rubber and The rubber reinforcing cord according to claim 1, Rubber products equipped with these features.

10. The aforementioned rubber reinforcing cord is embedded in the matrix rubber. The rubber product according to claim 9.

11. The aforementioned rubber product is a rubber belt. The rubber product according to claim 9.

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