JPS5921787A - Rubber reinforcing carbon composite cord - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carbon fiber composite cord for rubber reinforcement, and more specifically, the present invention relates to a carbon fiber composite cord for reinforcing rubber, and more specifically, the carbon fiber yarn is covered and integrated with organic fiber yarn outside or around the carbon fiber yarn by twisting or braiding, and Carbon fiber yarn and organic fiber yarn are coated with an adhesive before and/or after they are integrated, and are particularly used as tire cords or belt cords, and have improved adhesion to rubber and durability against bending. This invention relates to a carbon fiber composite cord for rubber reinforcement.

Conventionally, when rubber products such as tires, belts, etc. are used under the iM harsh strips, it has been used for reinforcement with a particularly high bow rate and high strength. There is a demand for fibrous materials that have the same characteristics, and hornless fibers and steel wires are used as fiber materials for reinforcing the comb.

However, glass fibers have disadvantages in that they not only have a higher density than organic fiber materials, but also have poor water-resistant adhesion and poor fatigue resistance. Steel wires not only suffer from poor adhesion as a result of rust growth due to moisture, but also have the drawback of extremely high density, which increases the weight of the product when exposed to heat.

In recent years, carbon fiber, which has been developed as a reinforcing material for reinforced plastics, has a lower density than steel wire or glass fiber, but still has high strength and elastic modulus, so it can significantly reduce the weight angle 1 of comb products. Crab expected.

However, carbon fiber has poor adhesion to the comb,
It also has the disadvantage of poor durability against bending and the like.

In order to improve these shortcomings, carbon fiber yarn was treated with resorcinol formaldehyde rubber latex (RF
L) Technology of twisting after treatment with liquid
-101686) has been developed, but there have been problems in that the adhesive strength with rubber is still insufficient and the bending resistance is also insufficient.

An object of the present invention is to provide a carbon fiber composite cord for rubber reinforcement that has improved adhesion to rubber and durability against bending, which are disadvantages of carbon fibers.

To achieve this purpose, it is sufficient to create a carbon fiber composite cord by twisting or braiding organic fiber threads around carbon fiber threads and integrating them into a carbon fiber composite cord. In order to impart this, an adhesive may be applied to each fiber thread before it is integrated, or an adhesive may be applied after it is integrated.

The structure of the carbon fiber composite cord for rubber reinforcement of the present invention is illustrated in the attached drawings. Among the accompanying drawings, FIG. 1 is a cross-sectional view of one embodiment of the composite cord of the present invention, and 1 is a carbon fiber yarn;
2 shows an organic fiber yarn, and FIG. 2 shows a cross section of another example. Figure 3 shows the organic fiber yarn 2 due to the twisting angle θ.
Fig. 4 shows a side view of a composite cord 5 in which carbon fiber yarn 1 is covered with carbon fiber yarn 1, and FIG. This is what is shown.

The carbon fiber yarn used in the core of the composite cord of the present invention is generally used for reinforced plastics, and has a strength of 100 kg/ran2 or more and a tensile modulus of 3000.
kg/mm or more, density 15-1.9 (g/cc,
), preferably a strength of 150 k17/mm2 or more and a tensile modulus of 5000 k
g7mm2 or more is used.

Further, the carbon fiber yarn in the core portion may be one or a plurality of carbon fiber yarns, and may be untwisted yarn, twisted yarn, or twisted yarn. When using twisted yarn or twisted yarn,
The number of twists added to the yarn is preferably 2000 or less given by the following equation (1). Adding more twist than that will not only cause filament breakage, but will also significantly impair the high strength and high modulus of carbon fiber.

K = TI/D (1) Formula % Formula % On the other hand, the organic fiber yarn surrounding the carbon fiber yarn may be made of natural fibers, recycled fibers, synthetic fibers, or mixed fibers thereof, monofilament yarn, multifilament yarn. Yarn, spun yarn, and twisted yarn of these yarns still refer to twisted yarn, but include 6 nylon multifilament yarn, 6.6 nylon multifilament yarn, rayon multifilament yarn, 71? Polyester multifilament yarn or aromatic polyamide fiber multifilament yarn is preferably used from the viewpoint of adhesion to the comb.

The method of covering the periphery of carbon fiber yarn with organic fiber yarn is usually done using multiple organic fiber yarns, and multiple yarns may be twisted in the same direction instead of one carbon fiber. ,
It is also possible to twist the threads so that they intersect, or to braid them so that the threads intersect.
You can also use J.

The thickness of each organic fiber thread used for twisting, twisting, or braiding is preferably the same or smaller than the cord diameter of the carbon fiber thread in the core. is preferably 1/2 or less of the cord diameter of the carbon fiber yarn.

In the case of twisting or braiding, the number of twists or the number of stitches varies depending on the number of organic fiber threads used for twisting or braiding, but
Sen! [, The twist angle θ (see Figure 3.4) of the organic fiber yarns relative to the Il+ direction is preferably selected within the range of 5° to 60°, and the number of organic fiber yarns is as shown below (2). The range expressed by the formula is usually used. □Adhesion treatment to impart adhesion to rubber may be applied to the carbon fiber threads and organic fiber threads individually before they are integrated as described above, or may be applied after they are integrated. Alternatively, after the treated carbon fiber yarn is covered with an untreated organic fiber yarn, the adhesion treatment may be performed again.

As the adhesive, RFL (an aqueous dispersion of formaldehyde initial condensate and rubber latex in resorcinol), which is usually used as an adhesive for rubber and fibers, is used.
A method may also be used in which pretreatment is performed with an epoxy adhesive, ison7ate adhesive, etc., and then RFL treatment is performed.

Hereinafter, the present invention will be explained in more detail with reference to actual examples.

Example 1 6 nylon 420d/1.800 denier, 3000 filament, non-twisted carbon fiber yarn (cord diameter 0.50 mm) for tire cord was wrapped around it. Number of twists: 10 times/1
0cm single twisted yarn (cord diameter 0', 20mm)
Eight cords were twisted in the same direction so that the twist angle θ was 25° to create a composite cord.

Next, this composite cord was coated with RFL and heat treated at 180° C. for 2 minutes. The obtained code is designated as A (see Table X for the RFL formulation).

Next, 1800 denier, 3000 filament carbon fiber yarn was coated with RFL and heat treated at 180°C for 2 minutes, then twisted 10 times/10 ctn, and further twisted with 10 twists/1 twist. Ply twisted (cord diameter 0
．． 75 in). 6 for tire cord around this thread.
Nylon 420 d/1, 8 single-twisted yarns with 10 twists/10 cm (cord diameter 0.20 mm) □The twist angle θ is 2
A composite cord was created by covering it with a 5° angle braid.

This was coated with RFL and heat treated at 180° C. for 2 minutes, and the resulting code was designated as B.

Furthermore, after applying RFL to 1800 denier, 3000 filament untwisted carbon fiber and heat-treating it at 180°C for 2 minutes, it was made into 6 nylon 420 d/1 twist number 1 for tire cord.
A composite yarn was prepared by twisting eight single-twisted yarns of 0 times 710 cnr and covering them in the same direction. This composite yarn was coated with RFL again and heat treated at 1.80°C for 2 minutes, and the resulting cord was designated as C.

For comparison, 1800 denier, 3000 filament, untwisted carbon fiber coated with RFL and heat treated at 180°C for 2 minutes, and 1800 denier, 30
Two 00 filament carbon fibers were first twisted at 10 times/10 crn, then twisted 10 times/1α, then coated with RFL and similarly heat-treated at 180°C for 2 minutes to create a product. Let the obtained codes be D and E, respectively.

- Embed the cords A-E obtained as described above in the unvulcanized rubber compound shown in Table 2 with a cord length of 8 mm.
The adhesive strength was measured by measuring the force of pulling the cord out of the vulcanized rubber after vulcanization at 8° C. for 30 minutes.

Furthermore, in order to evaluate the four-bending fatigue properties of these cords in rubber, a so-called dimmercher-type bending fatigue test was conducted in which the cords were embedded in rubber and bent at a constant stroke. The rubber compounded rubber shown in Table 2 was used. The plane 1 bending fatigue resistance of the cord in rubber was evaluated by determining the 100% ratio of the tensile strength after fatigue to the tensile strength of the rubber block in which the unfatigued cord was embedded. The above test results are shown in Table 3.

＼＼ ＼ ＼ Table 2 (Rubber compound) *4: Sandflex 13 (manufactured by Mitsubishi Monsite) *
By covering and integrating organic fiber threads around carbon fiber threads by twisting or braiding, as with 5-benzothyanol disulfide, not only the adhesion with rubber is greatly improved, but also the The durability against bending has been significantly improved.

The organic fiber yarn used in the composite cord not only plays a role in improving adhesion with rubber, but also plays a role in alleviating stress concentration on the carbon fiber yarn during bending fatigue and absorbing slight strain. It is thought that the fatigue resistance was improved, and that the improvement in the fatigue resistance was caused by the prevention of physical damage 2 to the carbon fiber filament due to adhesive interface fracture due to the improvement in adhesion.

The present invention has made it possible to easily use carbon fiber as a lightweight fiber-reinforcing material for fiber-reinforced rubber composite products such as tires, conveyor belts, and (1)-belts, which particularly require adhesion and fatigue resistance.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of one embodiment of the carbon fiber composite cord for rubber reinforcement of the present invention, Figure 2 is a cross-sectional view of another embodiment of the composite coat of the present invention, and Figure 3 is a twisted Figure 4 shows a state in which organic fiber yarn is covered around carbon fiber yarn, and FIG. 4 is a diagram showing a state in which organic fiber yarn is covered around carbon fiber yarn by braiding. be. 1: Carbon fiber yarn, 2: Organic fiber yarn, 3:1 silk, 4
: Twisting angle, 5: Carbon fiber composite cord for rubber reinforcement. Patent Applicant Yokohama Rubber Co., Ltd. Agent Patent Attorney Tatsuo Ito Agent Patent Attorney Satoshi Itoh Kazuo 1, Incident Indication 1982 Patent Application No. 12'7559 2, Title of Invention Carbon for Rubber Reinforcement! Lum combination code 3, relationship with the person making the amendment Patent applicant residence 5-36-11 Shinbashi, Minato-ku, Tokyo Name (
671) Yokohama Rubber Co., Ltd. Representative Hisaaki Suzuki 4, Agent 105 Address 2-8-1 Toranomon, Minato-ku, Tokyo 1988 1
October 7th (shipped on October 26, 1982) 6. In the specification to be amended, 13. Detailed description of the invention column” 7゜ Contents of the amendment Table 1, page 11 of the specification, page 12 of the same book Table 2 and Table 2 of the same book, page 13, Table 3 (Rubber compound) *4: Sandflex 16 (manufactured by Mitsubishi Monsite) *
5: Dipenzothiazyl disulfide

Claims (1)

[Claims] The organic fiber yarn is covered and integrated around the carbon fiber yarn by twisting or braiding, and the carbon fiber yarn and the organic fiber yarn are combined before and /'-! A carbon fiber composite cord for reinforcing a comb, characterized in that it is coated with an adhesive or is later coated with an adhesive, and has excellent adhesion to rubber and durability against bending.