WO2008041574A1

WO2008041574A1 - Aramid fiber cord for rubber belt reinforcement, process for producing the same, and rubber belt utilizing the cord

Info

Publication number: WO2008041574A1
Application number: PCT/JP2007/068644
Authority: WO
Inventors: Keisuke Kajihara
Original assignee: Nippon Sheet Glass Company, Limited
Priority date: 2006-10-03
Filing date: 2007-09-26
Publication date: 2008-04-10
Also published as: JP2010001570A

Abstract

A novel process for producing an aramid fiber cord for rubber belt reinforcement excelling in fraying resistance performance. A water soluble adhesive containing carbon black in a solid contents mass ratio of 5 to 50 mass% is applied to an untwined aramid fiber, and thereafter the aramid fiber is twined. The thus obtained aramid fiber cord for rubber belt reinforcement can be used as a reinforcing cord for various types of rubber belts, in particular, can be appropriately used as a reinforcing cord for synchronous belts, such as timing belt.

Description

Specification

Aramid fiber cords for reinforcing rubber belts, manufacturing methods thereof, and rubber benoles using the same

[0001] The present invention relates to a method for producing a rubber belt reinforcing aramid fiber cord for reinforcing a rubber belt. The present invention also relates to a rubber belt reinforcing aramid fiber cord manufactured by this manufacturing method and a rubber belt using the cord.

Background art

[0002] Reinforcing cords made of tough fibers are widely used as reinforcing materials for rubber products that repeatedly receive bending stress, such as rubber belts and tires. Reinforcing cords are required to have excellent bending fatigue resistance and dimensional stability.

[0003] One type of fiber used for reinforcing cords is aramid fiber. Aramid fibers generally have high strength and high elastic modulus, and are widely used as reinforcing cords for rubber belts for power transmission. In the case of a toothed belt such as a timing belt mainly used for driving a camshaft of an internal combustion engine, the reinforcing cord is exposed on the side surface of the belt during the manufacturing process, and the reinforcing cord is exposed from the exposed portion. There is a problem that aramid fibers tend to protrude from the side of the belt due to fraying.

[0004] In order to solve this problem, various improvements have been made to the method for producing aramid fiber cords.

[0005] For example, in JP-A-8-100370 (Reference 1), a substantially untwisted aramid fiber is treated with a treatment liquid containing an epoxy compound, heat-treated, twisted, and twisted. The aramid fiber was impregnated with resorcin / formalin 'latex (treatment liquid containing RFU under vacuum' pressure condition), and further heat treatment and treatment with treatment liquid containing RFL were incorporated into the belt. It is aramid fiber cord that is not easily frayed (aramid fiber cord with excellent fraying resistance).

[0006] Further, for example, in JP-A-8-284069 (Document 2), a substantially untwisted aramid fiber is treated with a treatment liquid containing an epoxy compound, subjected to heat treatment, and then treated with RFL. A treatment solution containing RRFFLL, which is twisted and twisted while applying the treatment solution, and further contains heat treatment and RRFFLL. In this and other places where the treatment process is performed according to the above, it is recommended to be a falamid mid-fiber fiber cord that excels in resistance to cheeks and has excellent characteristics. . .

[0007] Another example is, for example, in Japanese Patent Publication No. 1111 227799994499 (Bibliography No. 33), aralamidomid fiber is used as an isothiocyanate. After treatment with a treatment solution containing a compound and / or mep or epoxy compound, it contains RRFFLL. In this process, the aralamidod fiber is processed while the treatment liquid is being vibrated and vibrated by a supersonic wave vibration vibrator. It is considered to be a faramidamide fiber optic cord that has excellent resistance to hot and cold resistance and excellent characteristics. .

[0008] According to the manufacturing and manufacturing method method disclosed in the literature references 11 to 33, the processing under the conditions of true vacuum empty and pressurized pressure conditions There is a need for processing to be required, or it is necessary to perform processing by RRFFLL at the same time as twisted twist, For example, it is always necessary to produce and vibrate when vibrations caused by the supersonic wave vibration oscillators are required. It's eleena to be excelling in sex !! .

[0009] Other than that, Japanese Patent Publication No. 11 220077448800 (Public Literature No. 44), Japanese Patent Publication No. 44 2299664444 (Public Literature No. 55) )), And Japanese Laid-Open Patent Publication No. 66-2255997777 ((Literature Document 66)), it is known that A method of manufacturing and manufacturing a fiber optic code is disclosed and disclosed. .

[0010] It should be noted that although it is not a method for producing and producing a falamimid fiber fiber cord that has excellent resistance to hot-spotting and excellent characteristics, 44——Publication No. 118833112211 ((Bibliography 77)) describes the environmental load of the environment when making and manufacturing Gokoram supplementary reinforcement codecs. With the aim of lowering or lowering, it is representatively represented by go rubber muralate tex cousus and malaylay imido vulcanization aids. In order to improve and improve the adhesion between the cord and the matotriliques sago gum, the vulcanized vulcanization aid is the main component. Using a water-based adhesive agent that contains a smooth and easy-to-use adhesive. We have made production granulation how process method of the Kokododo for for auxiliaries reinforcing strength is have been shown to open disclosure contents. . Open disclosure of the invention

[0011] The present invention is different from the conventional manufacturing and manufacturing methods, which are different from these conventional methods of manufacturing and manufacturing, and are excellent in resistance to hot-spotting and excellent in characteristic properties. The purpose of the present invention is to provide a method for manufacturing and producing a balammiddo fiber optic cord for strong and strong use. .

[0012] The present invention invented rubber gum bevelt toughening reinforcing aralaramide fiber fiber cord (hereinafter referred to simply as "alaramidimide fiber fibril cordo") In the manufacturing and manufacturing method method of “Co-Corded” ”), the non-twisted twisted aralamidod fiber fiber is made into a solid / solid fractional mass ratio. After applying and applying a water-soluble adhesive adhesive agent containing 55 to 5500% by mass% of the weight ratio of the water-soluble adhesive agent, Twist twist the twisted fiber fibers. . As used herein, the term “solid solid fraction” as used herein means that the solvent solvent is excluded from the water-soluble adhesive adhesive agent. It is a general term for all the material substances that have been removed. In other words, ““ Solid-solid type mass fraction mass ratio is 55 to 5500 mass% mass%. “Contains the carbon black rubber” means that “the whole water-soluble soluble adhesive is contained in the entire material substance other than the solvent solvent contained in the water-soluble adhesive agent. In contrast to the mass and mass of

[0013] The falamimiddo fiber fiber cord according to the present invention is a code obtained by the above-described manufacturing method according to the present invention. . [0014] A rubber belt of the present invention includes the aramid fiber cord of the present invention, and has a structure in which the aramid fiber cord is embedded in a matrix rubber having a predetermined shape.

[0015] According to the present invention, an aramid fiber cord for reinforcing a rubber belt having excellent fraying resistance can be produced.

Brief Description of Drawings

FIG. 1 is a schematic view showing an example of a rubber belt of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0017] In the production method of the present invention, a water-soluble adhesive containing a predetermined amount of carbon black is applied to untwisted aramid fibers (application process), and then the aramid fiber to which the water-soluble adhesive is applied is applied. By twisting (twisting step), it is possible to obtain an aramid fiber cord having excellent fraying resistance. In the conventional methods for manufacturing reinforcing cords including Documents 1 to 7, no treatment liquid containing carbon black is applied to untwisted aramid fibers before twisting. For example, it has been shown that one or more treatment solutions may be applied to untwisted aramid fibers, and an RFL treatment solution containing carbon black may be applied at the final stage after twisting. (For example, described in paragraph number [0023] in document 1, paragraph number [0018] in document 2, table 1 in document 5, paragraph number [0022] in document 6, etc.). This is focused on the affinity between the matrix rubber that should embed the cord and carbon black, and the treatment liquid containing carbon black is finally applied for the purpose of improving the adhesion between the cord and matrix rubber. It has never been imagined by those skilled in the art to improve the fray resistance of the cord by applying a treatment liquid containing carbon black to untwisted aramid fibers. The purpose of adding carbon black to the water-based adhesive disclosed in Reference 7 is the same as that of the above-mentioned reference, and aims to improve the adhesion between the cord and the matrix rubber.

[0018] Note that "no twist" refers to a state in which filamentary aramid fibers are actively twisted by a twisting apparatus or the like!

[0019] The type of aramid fiber is not particularly limited, and can be used regardless of what is called para-type or meta-type, and may be a copolymer-type aramid fiber of a meta-type monomer and a para-type monomer. . Commercially available aramid fibers include, for example, para-type polyparaphenylene terephthalamide fiber (Toray 'DuPont's Kepler, Teijin's Twaron), meta-type poly-metaphenol. There are diene isophthalamide fibers (Conex manufactured by Teijin Ltd.) and poly 3, 4'-oxydiphenylene terephthalamide copolymer fibers (Technola manufactured by Teijin Ltd.) which are copolymer systems.

Yes

[0020] The water-soluble adhesive may contain 5 to 50% by mass of carbon black in terms of solid mass ratio. Hereinafter, this value is also referred to as “carbon black ratio”. The carbon black ratio is calculated by assuming that the mass of the entire material other than the solvent (typically water) in the water-soluble adhesive is W1, and the mass of the carbon black in the water-soluble adhesive is W2, and the carbon black ratio = (W2 / W1 ) This is the value given by the expression X 100 (%).

[0021] The carbon black may be contained in the water-soluble adhesive in a state of being dispersed in a solvent.

[0022] When the carbon black ratio in the water-soluble adhesive is less than 5% by mass, it is difficult to obtain an aramid fiber cord having sufficiently improved fraying resistance. In addition, if the ratio exceeds 50% by mass, the coating film formed by coating becomes insufficiently cured, causing problems such as the scattering of the adhesive in the subsequent twisting process. Spattering may reduce the uniformity of the coating film formed on the aramid fiber. When the uniformity of the coating film decreases, the function as a reinforcing cord decreases, for example, the adhesiveness with the matrix rubber decreases.

[0023] Various commercially available products can be used as the carbon black.

[0024] In addition to carbon black, the water-soluble adhesive contains various substances for ensuring or improving the adhesion between the polyamide fiber cord obtained by the production method of the present invention and the matrix rubber in which the cord is embedded. You may go out. The type of each substance can be selected as appropriate according to the type of rubber composing the matrix rubber.

[0025] For example, the water-soluble adhesive may further contain at least one selected from resorcin formaldehyde condensate and a vulcanizing agent and latex.

[0026] The resorcin formaldehyde condensate (RF) is not particularly limited, and resorcin-type RF obtained by reacting resorcin and formaldehyde in the presence of an alkaline catalyst such as alkali hydroxide or amine, or resorcin and formaldehyde. Nopolac-type RF obtained by reacting in the presence of an acid catalyst can be suitably used. Resol type RF and Nopolac type R May be mixed with F! /. In particular, using resorcinol (R) and formaldehyde (F) in a molar ratio, R: F = 2:;!

[0027] The vulcanizing agent is not particularly limited, and examples thereof include at least one selected from a sulfur compound, a peroxide compound, a maleimide compound, and an organic isocyanate compound.

[0028] The type of latex is not particularly limited. For example, butadiene styrene copolymer (SBR) latex, dicarboxylated butadiene monostyrene copolymer (modified SBR) latex, bullpyridine styrene butadiene terpolymer (VP) Latex, Isoprene Latex, Black Open Plain (CR) Latex, Chlorosulfonated Polyethylene (CSM) Latus, Acrylonitrile-Butadiene Copolymer (NBR) Latex, Hydrogenated Acrylonitrile Butadiene Copolymer (H-NBR) Latex , And at least one selected from ethylene propylene non-co-gen terpolymer (EPDM) latex! /,

[0029] The type of latex is also similar to the type of matrix rubber in which the obtained aramid fiber cord is embedded.

[0030] The water-soluble adhesive is a pH adjuster (eg, base, ammonia as a more specific example), stabilizer, thickener, anti-aging agent, etc. May be included.

[0031] The amount of each substance contained in the water-soluble adhesive excluding carbon black may be appropriately adjusted according to the type of matrix rubber in which the obtained aramid fiber cord is embedded.

[0032] Application of the water-soluble adhesive to the untwisted aramid fiber may be performed by applying a method generally used in the production of cords. For example, after aramid fibers are continuously introduced into a treatment tank containing a water-soluble adhesive, excess water-soluble adhesive is removed from the aramid fibers pulled up from the treatment tank, and dried or heat-treated as necessary. do it. When heat treatment is performed, it may be performed in a temperature range of about 140 to 300 ° C for about 30 to 240 seconds.

[0033] The amount of the water-soluble adhesive to be applied to the aramid fiber is not particularly limited and may be adjusted as appropriate. Force The mass of the whole substance other than the solvent contained in the water-soluble adhesive (that is, the water-soluble adhesive is The mass of solids to include), the range of 540% by mass of the mass of aramid fiber Power is preferable. When the value force is less than ¾% by mass, the fray resistance is not sufficiently improved. If the value exceeds 40% by mass, the ratio of the coating film thickness to the cord diameter becomes excessively large, which reduces the elastic modulus of the cord, or PLD (pitch line differential) during belt manufacturing. Defects may occur.

[0034] The aramid fiber having a coating film formed on the surface by the coating process is twisted by the twisting process.

[0035] The method of twisting, the specific twist shape, the number of twists, etc. are not particularly limited, depending on the type of matrix rubber in which the obtained polyamide fiber cord is embedded, or the type and size of the rubber belt. May be set as appropriate. More specifically, for example, using a twisting apparatus generally used for manufacturing cords, one or several aramid fibers are bundled and twisted to form a child bundle, and two child bundles are further added. The cords (twisted cords) may be formed by bundling them and twisting them.

[0036] The number of twists is not particularly limited, and the number of twists of the child bundle is, for example, 0 to 9.0 times / 25 mm, and the number of twists of the cord is, for example, 0.5 to 9.0 times / It is about 25mm.

[0037] The twisting direction is not particularly limited, and may be either the S direction or the Z direction.

[0038] The aramid fiber that has undergone the twisting step can be used as it is as an aramid fiber cord.

[0039] In the production method of the present invention, an adhesive different from the water-soluble adhesive may be further applied to the twisted aramid fiber according to the type of the matrix rubber to be embedded. As an adhesive different from the water-soluble adhesive, for example, an adhesive containing a latex and a crosslinking agent can be considered. In this case, a coating layer formed from the water-soluble adhesive is formed so as to contact the aramid fiber, and a coating layer formed from an adhesive different from the water-soluble adhesive is formed outside the coating layer. Is done.

[0040] The cord of the present invention can be used for various rubber belts, and can be suitably used for a toothed belt because of its excellent fraying resistance. Examples of the toothed belt to which the cord of the present invention can be used include various timing belts such as a timing belt for a printer in addition to a timing belt for an internal combustion engine.

FIG. 1 shows an example of the rubber belt of the present invention. A rubber belt 1 shown in FIG. 1 includes a amide fiber cord 2 of the present invention, and the cord 2 is a matrix rubber 3 having a toothed belt shape. It has an embedded structure. 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.

[0042] The structure and configuration of the rubber belt of the present invention are not particularly limited as long as it includes the aramid fiber cord of the present invention and the cord is embedded in a matrix rubber having a predetermined shape. The shape of the matrix rubber may be appropriately set according to the application and characteristics required for the rubber belt.

[0043] As a method for producing a rubber belt of the present invention, a general method for producing a rubber belt provided with a reinforcing cord such as aramid fiber cord may be applied.

Example

[0044] The production method of the present invention will be described in more detail with reference to examples. The present invention is not limited to the examples shown below.

First, a method for producing each sample of the example and the comparative example is shown.

[0046] (Examples;! To 6, Comparative Examples 1, 3 to 5)

A water-soluble adhesive having the composition shown in Table 1 below was applied to a non-twisted aramid fiber (manufactured by Teijin Ltd., Technora, wire diameter: 167 tex), followed by heat treatment at 200 ° C. for 120 seconds. Next, the heat-treated aramid fiber is twisted at a twist number of 1.0 times / 25 mm to form a child bundle, and three pieces of the child bundle are bundled in a twist direction opposite to the twist direction when forming the child bundle. Twisted with 0 times / 25mm twist number, aramid fiber cord Sampnore was obtained.

[0047] (Comparative Example 2)

Untwisted aramid fiber (Teijin Ltd., Technora, wire diameter 167 tex) is twisted at a twist rate of 1.0 times / 25mm to form a child bundle, and three pieces of the child bundle are bundled to form a child bundle. Twisting was performed at a twist number of 3.0 times / 25mm in the twist direction opposite to the direction. Next, a water-soluble adhesive having the composition shown in Table 1 below was applied to the twisted aramid fiber, followed by heat treatment at 200 ° C. for 120 seconds to obtain a aramid fiber cord sample. That is, in Comparative Example 2, the coating process and the twisting process were performed in reverse for each of the other samples.

[0048] [Table 1]

In Table 1, the amount of water-soluble adhesive applied to the aramid fiber is the dry weight W3 of the aramid fiber before the water-soluble adhesive is applied, and the dry weight W4 of the aramid fiber after the application. And determined by the formula ((W4—W3) / W3) 100 (mass%).

[0050] (Examples 7 and 8)

The aramid fiber cords prepared as Examples 1 and 2 were further coated with an adhesive having the composition shown in Table 2 below, and then heat-treated at 120 ° C. for 120 seconds to obtain an aramid fiber cord sample. The application amount of the adhesive shown in Table 2 is 5% by mass, and this application amount is calculated from the dry mass W5 of the cord before applying the adhesive and the dry mass W6 of the cord after application. ((W6-W5) / W5) It was determined by X100 (mass%).

[0051] [Table 2]

[0052] For each sample thus prepared, its tensile strength, elongation when a load of 100 N was applied, and fray resistance were evaluated. In addition, the applicability of the water-soluble adhesive used in the preparation of each sample to the aramid fibers was evaluated separately.

[0053] To determine the tensile strength of the sample, set the sample on an autograph (manufactured by Shimadzu Corporation, AG-10KNI type), pull the sample at a tension rate of 250 mm / min, and measure the load when the sample breaks. Determined by

[0054] The elongation of the sample was obtained by setting the sample on the autograph and measuring the elongation when a load of 100 N was applied. It can be said that the smaller the elongation value, the higher the percentage of the sample.

[0055] The fraying resistance characteristics of the samples were evaluated as follows.

[0056] First, after the sample was cut to a length of 200 mm, the length of the sample was placed on the surface of a sheet-like (size 25 mm x 200 mm, thickness 3 mm) matrix rubber precursor (the type of rubber is H-NBR). The length direction and the long side direction of the precursor are aligned, and adjacent samples are parallel to each other. Arranged without gaps. Next, a sheet-like matrix rubber precursor having the same size as described above was further stacked so as to sandwich the sample arranged above.

[0057] Next, the pair of precursors holding the sample was hot-pressed from both sides at 150 ° C for 20 minutes. Since a precursor containing a vulcanizing agent was used, the precursor became a matrix rubber vulcanized by hot pressing, and a rubber sample in which an aramid fiber cord sample was embedded could be produced.

Next, the produced rubber sample was cut in a direction parallel to the length direction of the sample using a cutter knife, and the state of the end face was visually evaluated. The evaluation was made on a five-point scale, where the cut surface was smooth and the aramid fibers were not frayed by the cut surface, “5”, and the cut surface was smooth but several aramid fibers were frayed by the cut surface. “4”, the cut surface is smooth, but several aramid fibers are protruding from the cut surface “3”, the cutting surface is a smooth force More than a dozen aramid fibers are protruding from the cut surface Is “2”, the smoothness of the cut surface itself is obtained! /,! /, And the state is “1”.

[0059] The applicability of the water-soluble adhesive to the aramid fiber was confirmed by visually confirming whether the adhesive was scattered or adhered at each part of the apparatus where the twisting process was performed. If it was not confirmed, “○: good”, and if scattering or adhesion was confirmed, “X: bad”.

[0060] Table 3 below shows the evaluation results of the above characteristics.

[0061] [Table 3]

Pull 3i¾J Load (薩) Applied Fray resistance

(N) Elongation (%) »| Raw

1 1100 0.8 4 〇

2 1200 0.7 3 〇

3 1000 1.0 5 〇

4 1100 0.8 3 ○

5 1100 0.8 5 〇

6 1100 0.8 4 〇

7 1200 0.7 5 〇

8 1200 0.8 4 〇

1 1000 1.0 2 X

2 1200 0.7 2 ○ 麵 3 1100 0.8 1 ○

4 1100 0.8 2 〇

5 1100 0.8 2 〇 As shown in Table 3, tensile strength of all samples was 1000N or more, and elongation at 100N load was 1.0% or less, and high strength and high elasticity aramid fiber cords were realized. I understood. However, Comparative Example 1 in which a water-soluble adhesive having a carbon black ratio of 60% by mass was applied, Comparative Example 2 in which a water-soluble adhesive was applied to twisted aramid fibers, and Comparative Example in which the water-soluble adhesive did not contain carbon black 3 and Comparative Examples 4 and 5 in which the water-soluble adhesive contains carbon black but the carbon black ratio is 3% by mass, the fraying resistance was as low as 2 or 1. On the other hand, it was found that in Examples 1 to 8 in which a water-soluble adhesive having a carbon black ratio in the range of 5 to 50% by mass was applied, the fray resistance was 3 or more and the fray resistance was improved. In particular, in Examples 7 and 8, in which a water-soluble adhesive having a carbon black ratio in the range of 5 to 50% by weight was applied, twisted, and then the adhesive shown in Table 2 was applied, the results are shown in Table 2. Compared to Examples 1 and 2 where no adhesive was applied, the fraying resistance was further improved. Further, in Comparative Example 1 in which a water-soluble adhesive having a carbon black ratio of 60% by mass was applied, the water-soluble adhesive itself was inferior in its applicability, and uniform application to the surface of the aramid fiber was difficult. [0063] The present invention may 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 are equivalent in meaning and scope to the claims are included in it.

Industrial applicability

[0064] According to the present invention, an aramid fiber cord for reinforcing a rubber belt having excellent fraying resistance can be produced.

[0065] The rubber belt reinforcing aramid fiber cord of the present invention can be used as a reinforcing cord for various rubber belts, and can be suitably used as a reinforcing cord for a toothed belt such as a timing belt. .

Claims

The scope of the claims

[1] A non-twisted aramid fiber is coated with a water-soluble adhesive containing 5 to 50% by mass of carbon black in a solid content ratio, and then twisted with the aramid fiber. Manufacturing method.

[2] The method for producing an aramid fiber cord for reinforcing a rubber belt according to claim 1, wherein the water-soluble adhesive further includes at least one selected from resorcin formaldehyde condensate and a vulcanizing agent and latex.

[3] Said latex power butadiene monostyrene copolymer latex, dicarboxylated butadiene-styrene copolymer latex, burpyridine styrene butadiene terpolymer latex, isoprene latex, black-opened latex, chlorosulfonated polymer 3. The rubber belt according to claim 2, wherein the rubber belt is at least one selected from a reethylene latex, an acrylonitrile monobutadiene copolymer latex, a hydrogenated acrylonitrile butadiene copolymer latex, and an ethylene propylene non-conjugated terpolymer copolymer latex. A method for producing a reinforcing aramid fiber cord.

[4] The amount of the water-soluble adhesive applied to the aramid fiber is 5 to 40% by mass of the mass of the aramid fiber in terms of the solid content of the water-soluble adhesive. A method for producing the aramid fiber cord for reinforcing a rubber belt as described above.

5. The method for producing an aramid fiber cord for rubber belt reinforcement according to claim 1, wherein an adhesive different from the water-soluble adhesive is further applied to the twisted aramid fiber.

[6] An aramid fiber cord for rubber belt reinforcement obtained by the production method according to claim 1.

[7] The rubber belt reinforcing aramid fiber cord according to claim 6,

A rubber belt having a structure in which the cord is embedded in a matrix rubber having a predetermined shape.

8. The rubber belt according to claim 7, which is a toothed belt.