JPH0124642B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a tire reinforced with carbon fiber,
More specifically, the present invention relates to the improvement of pneumatic radial tires using carbon fibers for belt members and carcass members, and is intended to improve durability and handling stability compared to conventional tires. Conventionally, steel wire was said to be the most excellent reinforcing material in terms of modulus as a fiber reinforcing element for radial tires, but when steel wire is used as a reinforcing material for the belt and carcass parts, the weight of the belt and carcass As a result, the increased centrifugal force causes problems such as the generation of standing waves and other tire failures, and the tread becomes very hard, resulting in poor riding comfort. In order to overcome this drawback, a pneumatic tire using carbon fiber as the tire belt member and carcass member via an adhesive was proposed as Japanese Patent Publication No. 56-40043.
To briefly explain this invention, as shown in Figs. 1 and 2, for example, a single filament
A bundle of 1,800 denier carbon fibers 1 with several 3,000 fibers per foot is first twisted, two fibers are combined and final twisted to make a tire cord, which is then dipped in an aqueous solution of an epoxy compound, dried, and coated with epoxy on its surface. After forming a resin layer 2, the cord is further immersed in an adhesive RFL to form an RFL adhesive layer 3, and then subjected to fixed length heat treatment,
A sudare weave of 1 inch per inch was prepared, both sides of the sudare weave were topped with a rubber compound, and several plies of the same were used as a reinforcing material for the belt portion of a radial tire. By the way, the tire of the invention is lighter and has better handling performance than tires using steel wire, but it has the disadvantage that good results are not yet obtained in terms of both durability and handling stability. There is. In other words, regarding the former durability, carbon fiber bundle 1
The epoxy resin layer 2 on the surface of the fiber bundle 1 is not permeated or impregnated into the inside, so the many filaments 1' inside are in direct contact with each other, and due to the friction between the filaments 1'. It is clear that the durability deteriorates as a result of fatigue, and the latter's handling stability is also due to the low compression modulus of the carbon fiber bundle 1. As a result of studies to improve the drawbacks, the present inventor found that
This invention has led to the creation of the present invention, in which carbon fibers (filaments) are dispersed and arranged in a liquid thermosetting resin or liquid rubber serving as a matrix phase, and then integrally cured, whereby the filaments are mutually cured. Since there is no direct contact between the filaments, fatigue of the filament does not occur, resulting in significantly improved durability.Also, by increasing the wire diameter of the filament due to matrix impregnation, an increase in compression modulus can be achieved. The present invention is intended to improve handling stability, and the gist of the present invention is that, as a tire reinforced with carbon fiber, a cord unit composite is formed by combining a large number of dispersed carbon fiber groups and a liquid liquid. The thermosetting resin or liquid rubber is solidified and integrally cured with the matrix phase interposed between the carbon fibers, the carbon fiber group accounts for 30 to 80% by volume, and the matrix phase accounts for 30 to 80% by volume. 20 to 70%, and the point is that the cord unit composite is used as a belt member or the like. The present invention will be explained in detail below. FIG. 3 is a sectional view of a cord according to the present invention, and FIG. 4 is a partially enlarged sectional view thereof, in which 10 is a carbon fiber (filament), 11 is a matrix phase, 12 is a cord unit composite, and 13 is the composite The body shows a cord made of five strands twisted together. First, the carbon fiber (hereinafter referred to as filament) 10 used in the present invention is a carbonized fiber obtained by firing an acrylic fiber in air, and a carbonized fiber obtained by further firing this carbonized fiber in an inert gas. Graphitized fibers, etc. The wire diameter of the filament 10 used is about 7 microns, and the cord unit composite 12
Use 1000 to 12000 bottles. Next, the matrix phase 11 of the present invention will be explained. The material constituting this matrix phase 11 has properties that allow sufficient adhesion to the filament 10, is liquid at room temperature, and has an elastic modulus of 50 Kg/cm ² to 10 ⁶ Kg/cm ² after curing. use. Examples of such a matrix include liquid resins such as polyether polyurethane, polyester polyurethane, and epoxy resin; liquid styrene-butadiene copolymer, liquid polybutadiene,
Examples include liquid rubbers such as liquid acrylonitrile butadiene copolymer. Among these, polyurethane-based liquid resins allow a wide selection of physical properties after curing and properties in an uncured state, are easy to cure, and have good shape retention after curing. In the present invention, a large number of the filaments 10 are dispersed in a matrix phase 11 made of the material, and as an example of a manufacturing method, a group of filaments pulled out from a reel is injected into a liquid thermosetting resin or An example of a means for impregnating or adhering the filament itself and the filaments to each other is by passing the filament through a bath containing liquid rubber.
The filament group impregnated with or attached with the matrix is passed through a heating furnace in a semi-hardened state to produce an integrally hardened cord unit composite 12 having a non-twisted, unidirectional reinforced structure. The composite composition in this die is expressed in volume percent, and the carbon fiber (filament) group is
30 to 80%, preferably 20 to 70% of the matrix phase. If the carbon fiber group is less than 30%, the cord unit composite 12 is too soft and the desired compression modulus cannot be obtained. Moreover, if it exceeds 80%, it will become hard and fatigue resistance will deteriorate, so it was limited to the above value. Next, 4 to 5 cord unit composites 12 are S-twisted with a lay length of 3.5 to 20 to form a tire cord 13, which is then woven into a sagging shape, and further coated with topping rubber to form a belt member or carcass. We get the parts. Examples and comparative examples of the present invention are listed below. Example Belt member A group of 600 denier carbon fibers with 1000 filaments were impregnated or adhered with polyether urethane. At this time, the volume ratio of carbon fibers, etc. is 50%, and the remainder is a matrix phase.The carbon fibers impregnated and attached with the matrix are passed through a mold and heating furnace heated to 100 to 120℃ in a semi-hardened state, and then untwisted. It was made into a cord unit complex with a unidirectional reinforced structure. Five pieces of this composite were made into a 1×5 tire cord by S twisting with a lay length of 10, then woven into a sudare shape, treated with Desmodille R as a brimer,
The topping rubber is made by blending 90 parts of natural rubber with 10 parts of polybutadiene-based liquid rubber, and blending 1.2 equivalents of MDI (methylene diphenyl isocyanate) as a chain growth agent for the terminal OH groups of the liquid rubber. Using. Carcass parts Nylon 840D/2 is used for the braai of the carcass part.
was used. Comparative example Both belt member and carcass member have 3000 carbon fiber filaments and 1800 denier carbon fiber group.
First twist 5zT/10cm, double the two threads, and then
After twisting 5S′T/10cm to create a cord,
After two-stage treatment with epoxy compound and RFL, it was made into a sudare weave, which was then topped on both sides with a rubber compound based on natural rubber. Comparative Example Steel cord (1×4×0.25) was used for both the belt member and the carcass member. The tire size to which the above Examples and Comparative Examples were applied was 165SR13, and the tire structure was as shown in Table 1 below.

[Table] Next, the performance test results of the above examples and comparative examples are shown in FIGS. 5 to 9. Figure 5 is a graph showing the relationship between cornering force (CF) and slip ankle, Figure 6 is a graph showing the relationship between cornering force (CC) and load, and Figure 7 is the relationship between μ and load. 8 is a graph showing the relationship between rotational resistance and speed, and FIG. 9 is a graph showing the relationship between logarithmic damping rate and internal pressure. In each figure, A represents the embodiment of the present invention. , B is a comparative example,
C indicates a comparative example, and Example A of the present invention shows better results in all respects than Comparative Examples B and C. This indicates that the present invention has superior durability compared to the conventional one. This shows that the vehicle has excellent performance and handling stability. As described above, the present invention is characterized in that a matrix phase formed by solidifying a large number of dispersed carbon fiber groups and a liquid thermosetting resin or liquid rubber is integrally cured under a specific volume percentage. Since it is a cord unit composite, it is used as a belt member and carcass member, so it has greater durability and handling stability compared to conventional carbon fibers using adhesives or steel wires. Excellent as something with improved characteristics.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views and partially enlarged views of a cord unit using conventional carbon fibers via an adhesive, and Figures 3 and 4 are cross-sectional views of a cord unit composite of the present invention. and its partially enlarged views, Figures 5 to 9
The figures show the performance test results of the tire according to the present invention and the comparative tire. Figure 5 is a graph of the relationship between cornering force and slip angle, and Figure 6 is a graph of the relationship between cornering force and load. The relationship graphs are as follows: FIG. 7 is a graph showing the relationship between μ and load, FIG. 8 is a graph showing the relationship between rotational resistance and speed, and FIG. 9 is a graph showing the relationship between logarithmic damping rate and internal pressure. 10... Carbon fiber (filament), 11...
Matrix phase, 12...Code unit complex, 1
3...Code.

Claims (1)

[Claims] 1 The cord unit composite 12 is formed by integrally curing a large number of dispersed carbon fibers 10 groups and a matrix phase 11 formed by solidifying a liquid thermosetting resin or liquid rubber and interposed between the carbon fibers 10. This means that the 10 groups of carbon fibers are 30 to 80% by volume, and the matrix phase 11 is 20 to 70% by volume, and the cord unit composite 12 is used as a belt member or the like. Tires reinforced with carbon fiber.