JPH07329520A - Bead material for bicycle tire - Google Patents

Abstract

PURPOSE:To resolve problems which conventional steel has, achieve light weight and favorable rim fit property, and prevent deterioration of the rim fit property or strength of beam material even when a bicycle is folded and carried for a long period. CONSTITUTION:In a bead material for a tire of a bicycle comprising a core- sheath type composite wire body composed of a reinforcement fiber bundle at a core part impregnated and coated with thermoplastic resin, it includes the core part comprising the reinforcement fiber bundle by 60-95 weight %, and a sheath part of the thermoplastic resin by 40-5 weight %, where the sheath part thermoplastic resin is impregnated in a surface layer of the reinforcement fiber bundle of the core part, with a surface of the sheath part PFL-processed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bead material (bead portion reinforcing material) for a bicycle tire.

[0002]

2. Description of the Related Art Conventionally, a steel wire has been mainly used as a core of a bead portion reinforcing material of a bicycle tire. That is, the role of the bead core is to fix the carcass ply and at the same time to fix the tire on the rim. Therefore, the conditions that it should have are that it has sufficient tensile strength and that it does not shrink due to heat during vulcanization or running. It is required that the material is a thermally stable material that does not occur, and that it has material properties such as low elongation and high elastic modulus so that it does not expand due to the internal pressure of the tire, and the adhesiveness with rubber is also an important factor. Is.

As a material satisfying such requirements, steel has been used overwhelmingly in consideration of cost. However, since steel has high rigidity, it is necessary to carry a spare tire for replacement when carrying it. It has a drawback that it cannot be folded, and that a large amount of force is required for the rim assembly at the time of replacement, which requires time and effort for replacement. Particularly in recent years, bicycle touring has become widespread for leisure and competition, and it has been desired to develop tires that can be folded and carried and that can be easily replaced while reducing tire weight.

In order to solve these problems, it has been considered to replace the bead wire, which has been mainly made of steel, with a fiber material having the same or higher physical properties. For example, Japanese Examined Patent Publication No. 56-22722 discloses a bead core that makes use of the characteristics peculiar to the organic fiber cord. However, since the method described in the above publication is a method that hardly generates resistance to bending and compression, bending rigidity is insufficient, and rim detachment of the bead occurs when an impact is applied during use of the tire. It has a drawback that it is easy and the shape retention during tire molding is poor.

On the other hand, Japanese Utility Model Laid-Open No. 1-16901 discloses a method of filling a fiber core of carbon fiber with a thermosetting resin to form a bead core. In general, inorganic fiber is brittle, and further, it is rigid. When the tire is covered with a high thermosetting resin, there is a problem that the core material is broken while the tire is folded and carried, and the tire cannot be fixed to the rim. Further, recently, from the viewpoint of resource saving, energy saving, and global environmental protection, it is desired to reduce the weight of a bicycle tire and to make a completely organic composite material that does not leave a reinforcing material or the like when burned and discarded.
A material that can replace steel is expected.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above problems of the prior art, to be lightweight and to have a good rim fit.
It is to provide a bead material for a bicycle tire, which does not deteriorate in rim fit and strength of the bead material even after being folded and carried for a long time.

[0007]

According to the present invention, there is provided a bead material for a bicycle tire, comprising: ((claim 1) a core-sheath type composite linear body obtained by impregnating and coating a reinforcing fiber bundle of a core portion with a thermoplastic resin. 60 to 95% by weight of the core portion made of the reinforcing fiber bundle and 40 to 5% by weight of the thermoplastic resin of the sheath portion, and the thermoplastic resin of the sheath portion is impregnated into the surface layer of the reinforcing fiber bundle of the core portion. A bead material for a bicycle tire, characterized in that the surface of the sheath is subjected to RFL treatment. (Claim 2) The reinforcing fiber is a para-aramid fiber, and the thermoplastic resin is a nylon resin. The bead material for a bicycle tire according to claim 1.

First, the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a manufacturing process of a bead material of the present invention. It is a schematic diagram showing one embodiment which coats aramid fiber with a thermoplastic resin. A plurality of continuous reinforcing fiber bundles F are guided from the bobbin 1 to the preheating heater 3 via the guide guide 2.
After being heated here, the components that cause gas generation in the molding step are evaporated and vaporized, and then introduced into the polymer reservoir 6 from the fiber bundle introduction side die 5 via the guide guide 4. Here, it is coated with a molten thermoplastic resin that is melted by a screw 9 and extruded through a throat 8, and is molded by a molding nozzle 11 that is heated to a temperature higher than the melting temperature of the thermoplastic resin through a lead-out die 7 and a cooling bath. While being cooled by 13, it is taken up by the take-up roll 14 via the guide guide roller 12. The strand-shaped resin-impregnated coated fiber is wound by the winder 15.

Para type aramid fibers (para type wholly aromatic polyamide fibers) are preferable as the reinforcing fibers used in the bead material of the present invention. Specifically, it is polyparaphenylene terephthalamide (for example, manufactured by DuPont, Kevlar, etc.), or poly 3,4′-oxydiphenylene terephthalamide (for example, Teijin Co., Ltd., etc.). As the reinforcing organic fiber, another kind of organic fiber of 15% by weight or less may be mixed and used.

Nylon (Ny) type resin is preferable as the thermoplastic resin for coating the reinforcing organic fiber bundle. Specifically, Ny-6, Ny-66, Ny-46, Ny-8, N
Examples thereof include y-10, Ny-612, Ny-12 and nylon elastomers. Polyethylene terephthalate (P
ET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyester resins such as polyester elastomers, olefin elastomers, polyacetals, polyphenyl sulfones (PPS), polyether ether ketones (PEEK)
Resins such as can also be used.

The present invention will be described in more detail below. That is, the bicycle tire bead material of the present invention is obtained by impregnating and coating a reinforcing fiber bundle with a thermoplastic resin, and the proportion of the reinforcing organic fiber bundle is 60 to 95% by weight. If the proportion of the reinforcing organic fiber bundles exceeds 95% by weight, the adhesiveness with rubber will be drastically reduced. If the proportion of the reinforcing organic fiber bundle is less than 60% by weight, the performance of the bead material is relatively deteriorated.

The bicycle tire using the bead material of the present invention has a rim fit of 2.5 kg or more to 4.0.
It has a performance of less than kg, and has a breaking water pressure resistance of about 11.0 to 15.0 kg / cm ² which is investigated by filling with water instead of air. When the strength of the bead material is less than 100 kg or the elongation of the bead material exceeds 1.6%, not only is the rim fit of the molded tire unstable and undefined, but at the same time, the fractured water pressure resistance of the molded tire is at the same time. Is 11.0 kg / c
It is less than m ² . Furthermore, the bead material of the present invention has a molded tire having initial values of rim fit and strength of the bead material of 95 even when the bicycle tire is folded and held for 3 months.
Holds performance of more than%.

A specific method for producing the resin-impregnated coated fiber of the present invention is a so-called pull-through method in which a thermoplastic resin is impregnated with a reinforcing fiber, or the reinforcing fiber and a fibrous thermoplastic resin are mixed. After the entanglement, the Commingle method of melting and solidifying the thermoplastic resin may be freely used. For example, 15% by weight of Ny-66 fiber is premixed with 85% by weight of aramid fiber and melt-extruded Ny-66 fiber is mixed.
A commule fiber of Ny-66 and aramid fiber is coated by a pultrusion method of impregnation in a melt of 66 resin.

Further, various additives for improving the properties of the reinforcing fiber or resin, such as a heat-resistant agent, a weather-resistant agent, an ultraviolet deterioration preventing agent, an antistatic agent, a lubricant, a release agent, a dye, a pigment, A twisting agent, a crystallization accelerator, an orientation accelerator, etc. may be added.

In the bead material of the present invention, the reinforcing organic fiber is coated with a thermoplastic resin, and the surface of the resin is RFL-treated. RFL is resorcin
Abbreviation for formalin rubber latex. The molar ratio of resorcin and formalin is preferably 1: 0.5 to 1: 8. The solid content weight ratio of resorcin / formalin and rubber latex is preferably in the range of 1: 3 to 1:20. As rubber latex, natural rubber latex, styrene-butadiene copolymer latex,
There are vinyl pyridine / styrene / butadiene / terpolymer latex, nitrile rubber latex, neoprene latex, etc. Among these, vinyl pyridine / styrene / butadiene / terpolymer latex is the most suitable when used alone or in combination of more than half. It shows excellent performance.

The bead material of the present invention has adhesiveness (T method) with rubber described later of 8 to 25 kg / cm. That is, in the bead material of the present invention, the surface layer of the reinforcing fiber bundle is impregnated with resin,
It has a structure in which a resin layer is formed thereon and a thin film-like RFL layer is formed thereon. Adhesion amount of RFL processing layer is 1-5
Weight percent is preferred. The RFL treated layer significantly improves the adhesion to the rubber layer of the tire.

[0017]

The present invention has the following effects.

The bead material of the present invention does not have too high rigidity and has good conformability to the rim. Further, by imparting an appropriate adhesiveness to the bead material, not only good rim fitting property is obtained, but also its durability becomes good. That is, if the adhesiveness value exceeds 25 kg / cm, the adhesion with rubber will be too high, and the reinforcing fibers will be properly deformed during folding to cause compression buckling, resulting in rim fit and strong durability during folding. Sex decreases. On the other hand, if the adhesiveness is less than 8 kg / cm, peeling between the bead core and the rubber occurs, so that the characteristics of the bead material cannot be fully utilized. According to the present invention, it is possible to provide a bicycle bead material that is much lighter than a conventional steel wire, does not rust, and has characteristics equal to or higher than those of a conventional one. A bicycle tire using this can be stored in a folded state, and as an alternative to the conventional steel wire, the bicycle tire can be made lightweight and rust-proof, and can be completely incinerated at the time of disposal, which in turn can greatly contribute to the protection of the earth's environment.

The present invention will be specifically described below with reference to examples. Regarding the state of impregnation of the sheath thermoplastic resin in the surface layer of the reinforcing fiber bundle of the core, the bead material was cut in a direction perpendicular to the long axis of the bead material, and the cross section was observed. The measuring methods used in the examples are as follows.

<Measurement of Reinforcement Fiber Occupancy> Length 20 mm
Of the bead material sample, the thermoplastic resin of the sample is dissolved and removed with a solvent, and then the weight of the reinforcing fiber is measured,
The occupancy of the reinforcing fiber was calculated.

<Strength, Elongation and Initial Modulus of Bead Material>Tentesco's tensile tester (model Intesco
Model 2005), using a 4D chuck, the sample length was 670 mm and the tensile speed was 250 mm / min.
The elongation under load, the elongation at break, and the initial modulus of 1% or less were measured.

<Occupancy Ratio of Reinforcing Fiber Bundle> It was calculated from the total fineness calculated from the weight of the reinforcing fiber bundle before resin coating and the total fineness calculated from the weight of the reinforcing fiber bundle after resin coating.

<Bending hardness> The bending hardness was calculated from the bending hardness measured by a Gurley type bending hardness tester manufactured by Tester Sangyo Co., Ltd.

<Rim-fitting property and pressure resistance when molding a bicycle tire> Six 26-inch size bicycle tires were made from the bead material of the present invention, and the tire beads were adhered to the rim by using the tires to form tires. The air pressure that was stably fixed to the rim was measured. Further, instead of air, water was filled into the tire, and the breaking water pressure resistance at which the bead portion broke and the water spouted was measured. After folding and storing the molded tire for 3 months,
Similarly, the rim fit property was actually measured and compared with the initial measured value of the rim fit property before folding and storing and rubbing.

<Adhesiveness to rubber (T method)> Both ends of the bead material subjected to RFL processing are U-shaped and have a depth of 1 cm NBR.
It was embedded in rubber and vulcanized, and the bead material was pulled out at room temperature using the tensile tester, and the strength at that time was measured as the adhesiveness.

<Strong Durability Test> Toyoseiki
MIT Flex Tester (MIT-D, Foldinn
g, Endurance Tester), the strength of the bead material after bending was forcibly bent 5 times at the same location, and the strength before bending and the strength before bending were measured and compared, and the strength retention ratio of durability was calculated. Bending speed is 170 times / min, bending angle is 270
Degree.

[0027]

[Example 1] 1500 denier / 1000 filament "Technora" yarn (para-aramid fiber manufactured by Teijin Ltd.)
4 strands are twisted together and 40 S / m of S twist is added to form one reinforcing fiber bundle. The reinforcing fiber bundle is heated with a preheater heated to 350 ° C. for 3 seconds and then led to the polymer pool. Then, the nylon 66 resin melted by a screw and controlled at 320 ° C. was impregnated into the fiber bundle under a pressure of 40 kg / cm ² , and then the inner diameter was 1.5 mm and the length was 2 mm.
It is drawn out from the lead-out hole of mm and is molded with a molding nozzle having an inner diameter of 1.0 mm and a length of 5 mm heated to 320 ° C.
Immediately cooled, a resin-coated strand was obtained. The molding speed at this time was 20 m / min. Here, this resin-coated strand was subjected to RFL treatment at 130 ° C. for 30 seconds and 2 times.
A heat treatment was carried out at 40 ° C. for 1 minute, and a 200 m trial bead material to which 2% by weight of the RFL agent was adhered was produced. The bead material thus obtained was bent 5 times at the same location with an MIT bending tester, the strength was measured, and the strength retention was calculated in comparison with the strength before bending, and was 98%. . Other physical properties of the bead material are as shown in Table 1. Further, six 26-inch size bicycle tires were molded using the bead material, and rim fitting property, pressure resistance and rim fitting property after pressure storage for 3 months were measured, and pressure resistance was measured.
Compared. The actual values of the sora are the performance results as shown in Tables 1 and 2, which are sufficiently durable for practical use as a bead material for bicycle tires.

[0028]

[Example 2] 1500 denier / 1000 filament "Technora" yarn (para-aramid fiber manufactured by Teijin Ltd.)
In the same manner as in Example 1 except that 20 strands / m of S twist were added to the fiber and then 20 strands / m of S strand were added as 4 reinforcing fiber bundles to perform the twisting process and the wire diameter was reduced. After processing, the performance results shown in Tables 1 and 2 were obtained. The bead material obtained in Example 2 is sufficiently durable for practical use.

[0029]

[Example 3] The same results as shown in Tables 1 and 2 were obtained by treating in the same manner as in Example 1 except that Ny-12 was used as the coating resin. The bead material obtained in Example 3 is sufficiently durable for practical use.

[0030]

Example 4 The same procedure as in Example 1 was repeated except that a polybutylene terephthalate resin was used as the coating resin and that the molding was performed with a heated molding nozzle having an inner diameter of 0.95 mm and a length of 5 mm. The performance results listed in Table 2 were obtained.
The bead material obtained in Example 4 is sufficiently durable for practical use.

[0031]

[Example 5] As a reinforcing fiber, 1500 denier / 10
40 filaments / m of 3 pieces of 00 filament "Technora" yarn (para-aramid fiber manufactured by Teijin Ltd.)
The performance results shown in Tables 1 and 2 were obtained by treating in the same manner as in Example 1 except that twisted fibers were used to form one reinforcing fiber. The bead material obtained in Example 5 is sufficiently durable for practical use.

[0032]

[Example 6] Nylon elastomer resin (E-62M-S3 brand, manufactured by Daicel Hüls) was used as the coating resin, and the same process as in Example 1 was repeated except that the resin extrusion temperature was changed. The performance results described in 2 were obtained. The bead material obtained in Example 6 is sufficiently durable for practical use.

[0033]

[Comparative Example 1] A bead material having the performance results shown in Tables 3 and 4 was prepared in the same manner as in Example 1 except that it was molded with a heated molding nozzle having an inner diameter of 1.4 mm and a length of 5 mm. Obtained. The bead material obtained in Comparative Example 1 had a large bending hardness, and when the strength was measured after being bent 5 times at the same location with the MIT bending tester, the strength was only 130 kg and the durability retention rate of the strength decreased to 93%. Was. In addition, the bead material obtained in Comparative Example 1 had a too large wire diameter cross-sectional area, and in the bicycle tire molding process, bulging occurred on both sides of the tire, and the molded tire was not distorted. The tire thus obtained was not practically usable.

[0034]

Comparative Example 2 1500 denier / 1000 filament "Technora" yarn (Para-aramid fiber manufactured by Teijin Ltd.)
2 fibers are twisted together and 40 S / m of S twist is added to form one reinforcing fiber, and heated inner diameter is 0.7 mm and length is 5 m.
The performance results shown in Tables 3 and 4 were obtained by processing in the same manner as in Example 1 except that the molding was performed using a molding nozzle of m. The bead material obtained in Comparative Example 2 was hard although the wire diameter was small. A closer examination reveals that the wire diameter cross-sectional area is too thin,
In addition, the tensile strength was also weak, and distortion did not occur in the bicycle tire molding process and was not corrected. The rim fit of the tire thus obtained is low and the breaking water pressure resistance is also low.
It was not practically usable.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

[Table 4]

[Brief description of drawings]

FIG. 1 is a bead material manufacturing apparatus (schematic diagram).

[Explanation of symbols]

 1 bobbin 2 guide guide 3 preheater heater 4 guide guide 5 introduction side die 6 polymer reservoir 7 discharge side die 8 throat 9 screw 10 die head 11 forming nozzle 12 guide guide roller 13 cooling bath 14 take-up roll 15 winder

Claims (2)

[Claims] 1. A bicycle tire bead material comprising a core-sheath type composite linear body obtained by impregnating and coating a reinforcing fiber bundle of a core portion with a thermoplastic resin, wherein the core portion comprising the reinforcing fiber bundle is 60.
˜95% by weight, the thermoplastic resin of the sheath portion occupies 40 to 5% by weight, the surface layer of the reinforcing fiber bundle of the core portion is impregnated with the thermoplastic resin of the sheath portion, and the surface of the sheath portion is RFL-treated. A bead material for a bicycle tire, which is characterized by being 2. The bead material for a bicycle tire according to claim 1, wherein the reinforcing fiber is a para-aramid fiber, and the thermoplastic resin is a nylon resin.