JPH05208458A - Manufacture of topping sheet for structure material of tire - Google Patents

Abstract

PURPOSE:To contrive to cut off woof in uniform lengths and to stream-line work by surely giving tensile force to the woof at every predetermined widthwise interval of sheet by a method wherein tire fabric is topped with rubber and, after being irradiated with electron rays, the woof of the tire fabric is cut off to the axial direction of the sheet. CONSTITUTION:Tire fabric 1 is woven of a large number of warps consisting of tire cord such as fiber cord or the like and woofs running crosswise to the longitudinal direction of the warps and passed through calender rolls 51 and 52 so as to top rubber R on both the sides of the fabric 1. By irradiating the resultant sheet with electron rays, crosslinking is developed in the topping. During the electron ray irradiating process 7, the sheet T is passed through an electronic protective box 71 so as to irradiate electron rays under the required acceleration voltage over one side of the sheet T with a first electron gun 72 and, at the same time, over its other side with a second electron gun 73. The electronically irradiated sheet T is passed between rolls 82 and 82 so as to cut its woofs into the lengths by pressing the one roll 82 against the other roll 82.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a topping sheet for a tire constituent material.

[0002]

2. Description of the Related Art Conventionally, as a tire constituent material such as a carcass and a belt of a tire, a large number of warp yarns made of fiber cords and the like are struck by a thin weft yarn which plays a role of a splice at every required longitudinal interval. A so-called topping sheet in which a woven bamboo blind fabric is topped with rubber by a calendar is generally used.

However, when the above-mentioned topping sheet is used as it is for the carcass layer of a tire, the weft yarn in the blind fabric does not play any effective role in reinforcing the tire, and the existence of this weft yarn rather improves the tire accuracy. There is a drawback to lower it.

That is, as shown in FIG. 7, in the state where the rubber (R) is topped on the interwoven fabric (11),
Since the wefts (13) crossing the warp (12) and alternately moving up and down are present, the parallel pitch (p) of the warp (12) tends to be non-uniform, and the weft (13) is also present. As a result, the warp yarns (12) are restrained, so that uniform inflation during vulcanization is hindered and tire uniformity is deteriorated.

Further, due to the influence of the above weft yarn (13), the warp yarns (12) forming the tire cord are not arranged in one plane but in a staggered arrangement, and therefore the thickness (g) of the surface layer of the topping rubber (R). To maintain a constant value, an extra rubber thickness is required, the amount of rubber used becomes large, wasting resources, and is an obstacle to weight reduction.

Therefore, as seen in JP-A-63-38006 and US Pat. No. 3,465,933,
In a topping sheet used for a tire constituent material such as a carcass layer, a weft cutting device called a pick breaker is used to cut the weft yarns of the interwoven fabric in rubber at required intervals in the sheet width direction to weaken the constraint, or It is proposed to cancel.

As shown in FIG. 5, the weft cutting device in the above proposal has a tapered projection (14a) (1) at a slight angle (about 15 °) at every required interval in the axial direction.
4b) having a pair of rolls (15a) (15b),
A sheet (T1) in which the projections (14a) and (14b) are staggered side by side and rubber (R) is topped on the interwoven fabric (11), the rolls (15a) and (15b) are attached.
By passing one roll (15a) against the other roll (15b) through the gap, the sheet (T1) is pressed and deformed by the protrusions (14a) and (14b) in a wavy manner as shown by the dashed line in FIG. , This allows the internal weft (1
A tensile force is applied to 3) to cut the weft yarn (13).

[0008]

However, when the above weft cutting device is incorporated into an actual calender line and used, the weft cutting length and frequency may become uneven, which is a tire uniformity. In some cases, the unevenness of the tire side portion was aggravated. This problem was increased when the thickness and the number of warp threads were changed, or when the topping gauge (rubber thickness) and the rubber composition were changed.

As a result of various studies on this, in the weft cutting action by the above-mentioned weft cutting device,
When the sheet (T1) is passed between the rolls (15a) and (15b) and pressed by the protrusions (14a) and (14b), the weft (13) is deformed and cut like the one-dot chain line in the figure. Since the topping rubber (R) is in a raw rubber state before vulcanization, the weft (13) may be displaced as shown by a broken line in the figure depending on the material of the warp (12), the rubber thickness and the composition. It was found that the tensile force may not be applied in some cases, and therefore, some portions cannot be cut, and the cut length of the weft (13) becomes uneven as shown in FIG.

Therefore, if the warp thickness, rubber thickness or composition of the warp weave fabric changes, the tire carcass material will be of good quality unless it is operated under various conditions such as the projection spacing and pressing pressure of the weft cutting device. Since a topping sheet cannot be obtained, it requires complicated work to stop the operation of the calendar line and change and adjust various conditions of the weft cutting device in accordance with the change in the above-mentioned blind fabric and rubber thickness. It was a thing.

The present invention has been made in view of the above, and in particular, a weft cutting device called a pick breaker is used as a topping sheet formed by topping rubber on a blind cloth, and the material of the blind cloth has a rubber thickness. The present invention provides a method for producing a topping sheet that can uniformly and surely cut the weft yarns of the interwoven fabric in rubber regardless of the composition and the like, and does not adversely affect the uniformity of the tire.

[0012]

A method of manufacturing a topping sheet according to the present invention which solves the above-mentioned problems is a method in which a warp yarn made of fiber cords, etc. It is characterized in that the sheet is irradiated with an electron beam to cause cross-linking in the topping rubber, and then the weft yarns of the interwoven fabric are cut at predetermined intervals in the sheet width direction.

In the above description, the weft is cut by applying a tensile force to the weft of the interwoven fabric by pressing and deforming the sheet in a wave shape through at least a pair of rolls having protrusions at every required interval in the axial direction. Do it.

[0014]

According to the present invention described above, since the topping rubber is crosslinked by electron beam irradiation after the rubber has been topped on the bamboo blind fabric, the topping rubber has a modulus due to the crosslinked state even if ordinary vulcanization is not performed. Has risen and is stronger than normal raw rubber.

Therefore, when the weft is cut at a predetermined interval in the sheet width direction in the subsequent step, the weft cutting is performed, for example, by corrugating the sheet through at least one pair of rolls having protrusions at every required interval in the axial direction. When the weft yarn is cut by applying a tensile force by being deformed by pressing, since the modulus of the topping rubber is high, the weft yarn is pressed and deformed without being displaced, and A tensile force can be surely applied at every predetermined interval in the sheet width direction, whereby reliable cutting can be performed.

Therefore, the weft can be reliably cut into a substantially uniform length even when the material of the blind cloth, the rubber thickness, or the composition changes. Further, by passing between a plurality of pairs of rolls, even if there is an uncut portion of the weft yarn on one roll, it will be cut on the subsequent rolls, so that it is possible to cut more reliably.

[0017]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a process diagram of a calendar line for producing a topping sheet (T) used for a tire constituent material such as a carcass of a radial tire.

The interwoven fabric (1) which is the core material of this topping sheet is composed of a large number of warp threads (2) which become tire cords such as fiber cords and weft threads (3) which are driven at predetermined intervals in the longitudinal direction. After being woven, subjected to heat treatment, adhesive treatment, etc., it is wound up.

As shown in FIG. 1, this blind cloth (1) is pulled out from a feeding device and fed through a controller (4) to a roll type calender (5) in the topping step, and the calender roll of this calender (5) is fed. (51)
The rubber (R) is topped on the front and back of the blind fabric (1) after passing through the space (52).

(6) is a cooling drum following the calender (5), (7) is an electron beam irradiation step, (8) is a weft cutting portion arranged after that, (9) is an accumulator,
(W) is a winder for winding the topping sheet.

In the electron beam irradiation step (7), as shown in the enlarged view of FIG. 2, the sheet (T) after the rubber (R) is topped is passed through the electron beam protection box (71). The first electron gun (72) irradiates one side of the sheet (T) with an electron beam at a required acceleration voltage, and similarly the second electron gun (73) irradiates the other side.
Thus, the electron beam is irradiated at a required acceleration voltage.

The accelerating voltage of the electron beam irradiation, and the irradiation amount or absorbed dose are set so that the topping rubber (R) is crosslinked to a certain extent by the electron beam irradiation according to the feeding speed of the sheet. .. For example, acceleration voltage 2
The absorbed dose is 1 to 3 MRad.

As described above, rubber (R) is added to the blind fabric (1).
The topping rubber (R) of the sheet (T) undergoes a certain degree of cross-linking due to a chemical reaction by electron beam irradiation after the topping of the rubber. Therefore, even if normal vulcanization is not performed, the modulus of the rubber (R) is changed. Rises and becomes stronger.

Then, in the subsequent weft cutting step (8), as shown in FIG. 3, as described in the description of the prior art, the projections (which are tapered at a slight angle at every constant interval in the axial direction). 81) and (81) are used, and at least a pair of rolls (82) and (82) having a groove width between the projections larger than the projection width is used. Both rolls (82)
(82) is arranged such that the projections (81) (81) are staggered, and is fed through a sheet (T) that has been subjected to electron beam irradiation treatment between the rolls (82) (82), One roll (82) to the other roll (8
By pressing it against 2), the weft (3) is cut into a required length.

That is, as described above, both rolls (82)
The sheet (T) passing between the (82) and (82) rolls (8)
2) When the projections (81) and (81) of (82) are pressed, they are pressed and deformed in a wave shape as shown by the chain double-dashed line in the figure, and pulled by the weft (3) inside them at predetermined intervals in the sheet width direction. A force is applied and the weft (3) is finely cut.

At this time, since the topping rubber (R) is crosslinked by electron beam irradiation and has a high modulus, the weft thread (3) is deformed by the protrusions (81) (81) when it is pressed and deformed. The weft yarn (3) is surely given a tensile force at predetermined intervals without being displaced to the surface side in the rubber, so that the weft yarn (3) is reliably cut at a predetermined position, and the cut length is It becomes almost uniform. In addition, (8
Although not shown in FIG. 1, 3) and (83) are cutting rolls having different projection pitches and phases from those of the rolls (82) and (82), and thus a plurality of pairs of rolls are used. By using it, it can be cut more reliably.

Further, if the warp yarn (2) of the interwoven fabric (1) is assumed.
Even if the material of the cord is changed, or the rubber thickness or composition is changed, the same cutting action is performed as it is without adjusting the cutting conditions by the weft cutting device, and it is possible to surely cut to a substantially uniform length. You can

Therefore, the restraint of the warp yarn (2) by the weft yarn (3) can be weakened or released almost uniformly over the entire surface of the sheet. Therefore, when using this topping sheet for the carcass layer of the tire,
Inflation during vulcanization is not hindered, and it is possible to prevent the occurrence of tire uniformity defects and tire side irregularity defects.

Since the topping rubber is crosslinked by electron beam irradiation as described above, natural rubber is styrene-butadiene rubber (SB).
It is desirable to use a rubber mixed with R). One example of the rubber compounding is shown below. ◎ Natural rubber (NR) 70 parts by weight Styrene-butadiene rubber (SBR) 30〃 FEF grade carbon (C) 45〃 Aroma oil 7〃 Zinc oxide (ZnO) 3〃 Stearic acid 2〃 Anti-aging agent 1〃 Vulcanization accelerator 1〃 Sulfur (S) 2〃

(Example 1) As warp, a yarn of 1500 denier of two twists of polyester fiber (cord) was arranged in a number of 25 / 2.5 cm, and as a weft, a cotton yarn of 20 count was 3/5 cm. After weaving with the number of hammered in, using an adhesive-treated suede woven fabric as usual, this suede woven fabric is flown through a calendar line shown in FIG. 1 and topped on the front and back sides with the rubber of the above formulation example, After the electron beam irradiation treatment, a topping sheet obtained by cutting the internal weft through a weft cutting process was obtained.

The results of examining the cut length of the weft yarn of this topping sheet are shown in Table 1 below. Further, for comparison, one that was subjected to electron beam irradiation treatment after cutting the weft (Comparative Example 1), one that was cut without wetting the electron beam (Comparative Example 2), and one that was not further cut (Comparative) Example 3) is also shown.

Then, the above-mentioned Example 1 and Comparative Examples 1-
A tire (size 165SR13) was manufactured by using each of the topping sheets of No. 3 as a carcass layer of a radial tire, and regarding tire uniformity, RFV (Radial Force V
ariation), LFV (Later-al Force Variation) and unevenness of the side portion were measured. The results are shown in Table 1 as an index with Example as 100.

[0034]

[Table 1]

As a result, in the example of the embodiment in which the weft cutting is performed after the electron beam irradiation treatment, the weft can be cut substantially uniformly and finely over the entire sheet, and the uniformity of the tire is improved as compared with the comparative example. It has been found.

(Example 2) As a warp, a two-twisted 840 denier yarn (cord) of nylon 66 is 15 yarns / 2.5 cm.
And weaving a number 30 cotton thread as a weft into a number of 3/5 cm indents, and further connecting an adhesive-treated blind cloth to the blind cloth used in Example 1 to continuously The topping sheet obtained by cutting the weft yarn through the weft cutting process after the rubber is topped with rubber on the front and back and then subjected to electron beam irradiation treatment is the same as in Example 1 above. The weft cutting length was examined. The results were obtained by subjecting the wefts to electron beam irradiation after cutting (Comparative Example 1), those obtained by performing weft cutting without electron beam irradiation (Comparative Example 2), and those not performing further weft cutting (Comparative Example 3). In addition to the case of Table 2 below
Shown in.

[0037]

[Table 2]

In each of the comparative examples, when the warp yarn is changed to nylon 66, the variation in the cut length of the weft yarn becomes large, whereas in the second embodiment, it is almost the same as when the polyester of the first embodiment is used for the warp yarn. It became finely and substantially evenly cut.

Therefore, according to the manufacturing method of the present invention, it has been found that even if the operation is not stopped and various conditions of the weft cutting device are adjusted and changed, the weft can be cut as it is to a substantially uniform length and the cutting efficiency can be improved. ..

[0040]

As described above, according to the method of manufacturing a topping sheet of the present invention, the topping rubber is subjected to electron beam irradiation treatment after the rubber topping to leave the crosslinked state of the topping rubber, and then the weft cutting of the interwoven fabric is carried out. Therefore, when the weft is cut, especially when the sheet is pressed and deformed in a wave shape through a pair of rolls having protrusions to cut the weft, the weft is reliably pulled at predetermined intervals in the sheet width direction. A force can be applied and the weft can be cut into a substantially uniform length.

Further, since it is possible to surely cut into a substantially uniform length regardless of the material of the warp (cord) of the suede woven fabric or the rubber thickness and compounding, the process and various cutting conditions are different for each type of topping sheet. It is possible to improve the efficiency of topping and weft cutting work by a calendar line without the trouble of changing and adjusting.

As described above, since the weft can be cut substantially uniformly, the restraint of the warp by the weft can be weakened substantially uniformly over the entire surface of the sheet, and the ruin can be released. Therefore, the thus produced topping sheet can be used for the carcass of the tire. When used as a layer, there is no risk of hindering inflation during vulcanization, and it is possible to prevent the occurrence of tire uniformity defects and irregularities on the tire side portions.

[Brief description of drawings]

FIG. 1 is a schematic process drawing of a calendar line for carrying out the method for producing a topping sheet of the present invention.

FIG. 2 is an enlarged view of an electron beam irradiation process portion of the above.

FIG. 3 is an enlarged cross-sectional view of the above weft cutting step portion.

FIG. 4 is an enlarged cross-sectional view of a part of the topping sheet with the wefts cut.

FIG. 5 is an explanatory diagram of a weft cutting state by a weft cutting device called a pick breaker.

FIG. 6 is an enlarged cross-sectional view of a part of a conventional topping sheet in which a weft is cut.

FIG. 7 is a partial enlarged cross-sectional view showing a conventional topping sheet made of a blind cloth.

[Explanation of symbols]

 (1) Suede woven fabric (2) Warp (3) Weft (5) Calendar (7) Electron beam irradiation step (72) First electron gun (73) Second electron gun (8) Weft cutting step (81) Protrusion (82) Roll (83) Roll (R) Topping rubber

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C08J 5/04 7188-4F D03D 1/00 A 7199-3B // B29K 21:00 105: 24 B29L 30:00 4F

Claims (2)

[Claims] 1. A topping fabric woven by wefting warp yarns made of fiber cords and the like is topped with rubber, and then this sheet is irradiated with an electron beam to crosslink the topping rubber. A method for manufacturing a topping sheet for a tire component, comprising cutting the weft yarn at a predetermined interval in the sheet width direction. 2. The topping for a tire constituent material according to claim 1, wherein the weft yarn of the interwoven fabric is cut by pressing and deforming the sheet in a wave shape through at least a pair of rolls having protrusions at every required interval in the axial direction. Sheet manufacturing method.