JPS6143457B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvement of the edge of a blind fabric for rubber reinforcement, particularly a blind fabric used for reinforcing tires.

In general, blind fabrics are widely used as reinforcing materials for rubber products such as tires and belts.In particular, blind fabrics used for reinforcing tires, for example, are made by closely arranging the warp yarns of relatively thick cords, and are also used as yarn arranging materials. Weft yarns such as spun yarns with relatively small diameters are arranged and woven to a predetermined width. The blind fabric is then treated with adhesive and heat treated under certain conditions, coated with unvulcanized rubber, and cut diagonally at a predetermined angle with a bias cutter.The cut sheet 1 is shown in FIG. A band-shaped intermediate material is created by sequentially pasting each other at the edge portions a as shown in FIG. When joining the cut sheets 1 to each other, it is inevitable to form a joint J in which the cords overlap each other with a constant width Wo in the longitudinal direction at the edge a. When the intermediate material having such a joint J is used as a tire reinforcing material, the force applied to one cord at the joint J is smaller than that at other parts, resulting in the following problem.

(1) The cord set due to post-cure inflation is less at the joint J, which causes unevenness on the side of the finished product.

(2) When the tire is filled with internal pressure, the joint J has less elongation than other parts, so the surface corresponding to the joint J becomes concave.

(3) The growth of the tire due to long-term driving is less in the joint J than in other parts.

(4) Rigid faults occur between joint J and other parts, and become the core of failure due to stress concentration.

All of these impair the aesthetic appearance and are also undesirable in terms of maintaining the uniformity of the product.

In order to solve the above problems, the inventor generally proposed
No. 55-14047 (see Japanese Unexamined Patent Publication No. 112533/1983), a technique was disclosed in which the edge of the selvage was formed using only high-elongation warp yarns.

Although the above-mentioned problems have been almost solved using this technique, since the cords are concentrated at the edge of the ear, they are stretched during the process, resulting in the problem of disordered cords at the edge of the ear.

It is an object of the present invention to solve these problems and provide a blind fabric used for reinforcing rubber products such as tires and belts, which has better aesthetic appearance and uniformity.

The present invention provides a blind fabric in which warp threads are arranged parallel to each other at predetermined intervals, and the warp threads are bound by weft threads at relatively coarse intervals. This is a rubber-reinforcing blind fabric characterized by forming a joint in which warp yarns are alternately arranged.

The present invention will be explained in detail below with reference to the drawings.

FIG. 2 is a schematic view showing the joints of the blind fabric of the present invention. Here, the selvage edge a is the warp yarn 4 with high elongation.
The warp yarns 5 used for areas other than the edge edge a are alternately arranged one by one. However, during the process, the ear edge a
This prevents the warp yarns with high elongation from being stretched, prevents cord disorder, and further reduces the dimension W of the joint.
Even if the dimension Wo becomes smaller than the planned dimension Wo, the deterioration of the physical properties of the part is alleviated.

Note that the high elongation warp yarns 5 do not necessarily have to be arranged alternately one by one as shown in FIG. 2, but as shown in FIG. 3. Two pieces may be used as a pair, five or less pieces may be made as a pair, and a fourth piece may be used as a pair.
As shown in the figure, the regularity of the arrangement is not required.

Here, it is preferable that the end of the selvage edge a be constructed of warp yarns 5 used outside the selvage edge, as shown in FIGS. can be prevented.

Here, high elongation warp yarns are those whose cutting elongation is based on JIS.L-1017 after heat setting the blind fabric.
At least 40%. When such high elongation warp yarns are used for the selvage edge portions, the stress burden due to the high elongation warp yarns 4 on the selvedge portions a of the joint J becomes extremely small. In other words, the warp yarns 4 having high elongation at the selvage edge a easily elongate in response to tension, and have large creep, so they hardly contribute as resistance to the load. Therefore, the amount of deformation due to tension or pressure in the joint J and other parts is almost uniform, and the above-mentioned problems in tire products can be solved. The high elongation warp yarn preferably has a breaking elongation of 80% or more and a birefringence of 0.11 or less. Particularly when applied to the carcass of a tire, the composition within these ranges can effectively prevent unevenness of the side portion due to internal pressure filling and tire growth after long-distance running.

In particular, the high elongation warp used for the edge of the blind fabric of the present invention has a stress relaxation rate C defined below of 50% or less after heat setting the blind fabric.
It is preferably 20% or less. In other words, if a load of 0.5 g/d is applied to the warp yarn at room temperature and the warp yarn is placed in a hot air dryer at 130℃ at a constant length, the stress will suddenly drop to the bottom as shown in Figure 5. However, the stress stabilizes at a constant value after a few minutes. Therefore, we measured the stress value S after holding at that temperature for 10 minutes,
This stress relaxation rate C is expressed as C=S/0.5×100.

Next, the high elongation warp yarns should have a dry free shrinkage rate of -4% to +40, particularly -2% to +2%, under conditions of 150°C for 30 minutes after heat setting the blind fabric. preferable. This is generally a smaller value than the physical properties of the warp yarns other than the edge edges, and as a result, the heat shrinkage due to heat generation during the tire vulcanization process and running is small, and the heat shrinkage behavior is substantially different from that of the parts other than the joints. This makes it possible to maintain uniformity.

The width of the high elongation warp yarns arranged at the selvage a of the blind fabric is 2 cm or less, preferably 1 cm or less, in consideration of separation of the joint in a later process.

The diameter of the warp yarn of the selvage edge a is 20 to 120% of the diameter of the cord of the other warp yarns. If it is less than 20%, there will be problems such as separation of joints and poor shape of the webbing fabric.
Moreover, if it exceeds 120%, the thickness and rigidity of the joint will increase, impeding uniformity. In addition, the material of the warp yarns at the edge part a can be polyester, nylon, rayon, aromatic polyamide fiber, etc., but in order to maintain the uniformity of the reinforced product, the same material as the warp yarns other than the edge part a should be used with high elongation. , it is preferable to use a low heat shrink yarn.

In addition, in the blind fabric of the present invention, the selvedge portion on which the high-elongation warp yarns are arranged can be placed not only on one side of the fabric, but also on both ends.

Examples will be specifically explained below.

Example 1 Warp yarn with polyester fiber density of 1500d/2
Width 5mm on one side of 55 pieces/5cm of blind fabric
1430d- spun at a speed of 3800 m/min at the edge of the ear
468fil polyester long fiber (Δn=0.040, crystallinity=27%, boiling water shrinkage=46%, cutting elongation=161
%) was first twisted at 400t/M, then the same number of final twists were applied, and heat treated in drying at 120℃ for 1 hour (Δn=0.093, crystallinity=36%,
Cutting elongation = 146%, dry heat free shrinkage rate 0 at 150℃ for 30 minutes
%) were woven by arranging three strands one by one alternately as shown in FIG. This fabric was immersed in a resorcinol-formaldehyde (RFL) solution having a composition that imparts adhesion to rubber and dried at 150°C for 4 minutes. After that, net stretch 0.5% at 240℃ for 2 minutes.
Heat set with . After heat setting, the high elongation warp yarn at the selvage edge had a strength of 8 kg, a breaking elongation of 125%, a birefringence of 0.095, and a dry heat free shrinkage rate of 1%. The cord warp of this warp was the same as the cord diameter of the other parts, and the stress relaxation rate was 10%. This blind fabric was rubberized and cut to a constant width, and then joined together so that five warp yarns (width 5 mm) overlapped each other at the edge of the selvedge to create an intermediate material for a tire carcass. Using this, a monoply 165SRI3 tire was manufactured.

There is no cord disturbance at the ear edge during the tire manufacturing process, and even when the tire is new, there are no irregularities caused by the joints, and the load is 558 kg and the mileage is
5000 and a speed of 80 km/h, no unevenness due to tire growth was observed.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the joints of the blind fabric, Figures 2 to 4 are schematic diagrams showing the joints of the blind fabric of the present invention, and Figure 5 is a reference diagram for expressing the creep retention rate Co. be.

Claims (1)

[Scope of Claims] 1. A blind fabric in which warp threads are arranged parallel to each other at predetermined intervals, and the warp threads are bound by weft threads at relatively coarse intervals, in which a high elongation warp thread is attached to at least one edge of the blind fabric. A rubber-reinforcing blind fabric characterized by forming a joint in which commonly used warp threads are alternately arranged. 2. The rubber-reinforcing blind fabric according to claim 1, wherein the selvage edge portion is formed by alternately arranging high elongation warp yarns and commonly used warp yarns in pairs of 1 to 5 warp yarns. 3. The rubber reinforcing blind fabric according to claim 1, wherein a commonly used warp yarn is arranged at the end of the edge edge. 4. The blind fabric according to claim 1, wherein the high elongation warp yarns are polyester fibers. 5. The blind fabric according to claim 1, wherein the high elongation warp yarns have a birefringence of 0.11 or less and a cutting elongation of 40% or more after heat setting the blind fabric. 6. The blind fabric according to claim 1, wherein the cord diameter of the high elongation warp yarns is 20 to 120% of the cord diameter of the warp yarns in other parts. 7. The blind fabric according to claim 1, in which the selvage edge has high elongation warp yarns arranged in a width of 2 cm or less. 8. The blind fabric according to claim 1, wherein the high elongation warp yarn has a dry heat free shrinkage rate of -4% to +4% at 150°C for 30 minutes.