JPH0286428A - Manufacture of solid tyre - Google Patents

Abstract

PURPOSE:To vulcanize a central part following an outer surface, and shorten the vulcanizing period and improve the productivity by disposing an insulating part having a fast vulcanizing speed at the central part during the tyre molding period. CONSTITUTION:An insulation part 9 having a fast vulcanizing speed is disposed on a tyre central part M. Through this manner, the central part M can be vulcanized following the tyre outer surface, and the vulcanized degree of the tyre outer surface and inner surface becomes uniform. And, the vulcanizing time is shortened, and the productivity is improved, and besides, the occurrence of separation due to the early removal from the mold can be reduced. And, the influence to the fitted part with a rim is prevented by providing the insulation part 9 on the central part M of a tyre, furthermore, the burning in the period of pre heating a raw tyre is prevented, and an adhesion defect can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a solid tire to be mounted on an industrial vehicle used at low speed, such as a forklift or other on-site transportation vehicle.

These tires are used under severe conditions such as bearing large loads and increasing rolling resistance, and so-called solid tires, in which the entire tire is a solid body, are often used to prevent banks from forming during use. In addition, it is essential for this solid tire to prevent slipping with the rim while running, and for this reason, as shown in FIG. What to embed, No. 5
As shown in the figure, the tire has a two-layer structure in which the base part B on the side that contacts the rim R is formed using a composite of fiber and rubber with a high compressive elastic modulus, and the cap part C on the side that contacts the ground is made of rubber. Some use a base T. Furthermore, foil WH
As shown in Fig. 6, there is a structure in which the tire base T is bonded directly to the steel baseband RB by vulcanization, and in this case, the outer diameter of the wheel WH and the inner diameter of the baseband are They are fitted with an interference margin between them. Note that it is preferable to use hard rubber as the tire base T.

On the other hand, since this type of solid tire has a thick wall, when using the conventional vulcanization method using an external heat medium, the temperature at the center part M of the tire decreases due to the low thermal conductivity of rubber. As shown by curve a in Figure 7, the temperature rises later than that of the surface N shown by the curve, and even when the mold is opened at the end of vulcanization in the press (point Pi), the temperature rises from the press hot platen. Although the supply of heat is stopped, the temperature of the central portion M of the tire continues to rise due to so-called after-cure. Therefore, in the conventional method, (1) it is difficult to uniformly supply heat to the tire center M and the tire surface N;

■ It takes a long time to complete the vulcanization of the center part M of the tire, resulting in long press usage times and low production capacity.

In addition, the tire surface N becomes reverse vulcanized.

There are other problems.

Therefore, in order to increase productivity, it is conceivable to shorten the time until the mold is opened, for example.

[Problem to be solved by the invention]

However, shortening this time tends to result in insufficient vulcanization of the tire center region M.

Moreover, when the mold is opened, the tire inside the mold rapidly expands at a high temperature, and at this time, if the degree of vulcanization in the center part M of the tire is insufficient, small bubbles and separations are generated inside due to the expansion force. .

Also, the air contained in the rubber migrates into this separation area and promotes this separation.

Note that when the tire base T is formed by winding a rubber sheet, the separation mainly occurs due to the separation of adjacent parts of the rubber sheet,
In particular, in the two-layer structure of base rubber B and camp rubber C shown in FIG. 5, the separation is likely to occur at the boundary.

The present invention is based on speeding up vulcanization in the center of the tire, enables uniform vulcanization of the entire tire, and further improves productivity by shortening the time required to complete vulcanization. The purpose is to provide

[Means to solve the problem]

The present invention is a method for manufacturing a solid tire, characterized in that an insulation portion having rubber having a faster vulcanization rate than the rubber forming the tire base is provided inside the tire base in the tire circumferential direction. .

[Effect]

Since the insulation part with a high vulcanization speed is arranged in the center of the tire, the center can be vulcanized following the outer surface, and the degree of vulcanization O on the outer and inner surfaces of the tire becomes uniform. Furthermore, it is possible to shorten the vulcanization time, increase productivity, and reduce the occurrence of separation due to early removal from the mold. Further, by providing an insulation part in the center of the tire, it is possible to eliminate the influence on the fitting part with the rim, and also to prevent burning during preheating of the green tire, and to reduce adhesion failure.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

FIG. 1 illustrates a tire 1 having a tire base 4 made of a two-layer structure of base rubber 2 and cap rubber 3, where the base rubber 2 is a pace rubber sheet 5 made of a composite of fiber cords and rubber. By laminating a plurality of sheets, the cap comb 3 is formed by winding and laminating M cap rubber sheets 6 made of rubber. Further, the tire center portion M of the tire base 4 straddles the base rubber 2 and the cap rubber 3.
is provided with an insulation part 9 having insulation rubber for accelerating vulcanization. Further, in this example, the insulation section 9 includes an insulation sheet 7 having a thickness tl of, for example, 0.5 to 5 thick, between the sheets 5.5,
It is formed by the insulation sheet 7 and the rubber sheet 5.6 between them by inserting the insulation sheet 7 as appropriate between the sheets 6.6 and between the sheets 5.6 and winding them together.

Furthermore, in order to prevent the performance of the finished tire from deteriorating due to burning, etc., the insulation rubber is super-accelerated into a rubber base material with substantially the same composition as the rubber of the rubber sheet 5.6 forming the tire base 4. It is best to use a mixed rubber with additional agents added.

Further, as a super accelerator, for example, a thiuram type, a dithiocarbamate type, or a mixture of these and other accelerators can be used, and the amount of this super accelerator is 3.0 parts by weight per 100 parts by weight of the rubber base material. 1.0 parts by weight or less, preferably 1.0 parts by weight or less. The weight part of the super accelerator should be within the above range and within the material and thickness t2 of the rubber sheet 5.6 so as to promote the vulcanization of the rubber sheet 5.6 between the insulation sheets 7.7. , optimally depending on t3! 1! It will be arranged.

Furthermore, the tire center portion M in which the insulation portion 9 is provided is defined as:
Height H2 of the insulation portion 9 and tire cross-sectional height H
The ratio H2/H1 to l is 0.05 or more and 0.7 or less, preferably 0.1 or more and 0.5 or less, and the ratio H3/H1 of the intermediate height 113 and the tire cross-sectional height H1 is H1
0.35 or more and 0.65 or less, preferably 0.45
or more and 0.55 or less, and the ratio W2/Wl of the width W2 of the insulation portion 9 to the tire width W1 at the intermediate height (H1/2) of the tire base 4 is 0.5 or more and 0.
The range is 8 or less.

By providing the insulation part 9 in the tire center part M in this way, the vulcanization speed between the outer surface and the center part M can be made uniform, and the insulation part 9 in the tire center part M can be made uniform.
By arranging the tire, there is no influence on the fitting part with the rim R (and it reduces adhesion failure due to burning of the rubber during preheating of the green tire).

In addition, in order to effectively promote vulcanization by insulation in the tire center part M, the thickness t2 of the rubber sheet 5.6 is
, t3 is 15 mm or less, preferably 5 to 1 (1 m).

The raw cover tire thus formed is placed in a vulcanization mold and vulcanized for a predetermined period of time in the same manner as in the conventional method.

FIGS. 2 and 3 show other embodiments that can be manufactured according to the present invention, in which an insulation part 9 is provided in the tire center M, respectively.

In addition to using the sheet 7, the insulation part 9 can also be formed by disposing a thick ring-shaped body made of insulation rubber in the center part M of the tire. 5. In the prescribed part of 6,
It can also be formed by applying a super accelerator using an appropriate solvent.

(Example) A solid tire with tire size T500-8DC and the structure shown in Figure 1 was prototyped using the formulation shown in Table 1 and compared with the conventional manufacturing method.
3/H1 is 0.5, W2/Wl is 0.65, and j7 of the insulation sheet. The thickness 1 is 2III11, and the thicknesses t2 and t3 of the rubber sheet 5.6 are 10.

The vulcanization conditions for tires without insulation are 15
The method of the present invention required 130 minutes at 3°C.
Equivalent performance was obtained at 53°C for 110 minutes. Therefore 1
It became possible to shorten the vulcanization time by 5%. Furthermore, the outer surface and interior of the tire can be evenly and flatly vulcanized.

〔Effect of the invention〕

As described above, the present invention has an insulation part with a high vulcanization speed placed in the center of the tire during molding, so
The central part can be vulcanized following the outer surface, shortening the vulcanization time and increasing productivity, and reducing the occurrence of separation due to early removal from the mold. Further, by providing the insulating silon part only in the center of the tire, it is possible to eliminate the influence on the fitting part with the rim, prevent burning during preheating of the green tire, and reduce adhesion failure.

Furthermore, when using an insulated silicone sheet, the insulated silicone portion can be formed easily and accurately, and productivity can be improved.

[Brief explanation of the drawing]

Figures 1 to 3 are cross-sectional views illustrating tires obtained by the method of the present invention, Figures 4 to 6 are cross-sectional views illustrating conventional tires, and Figure 7 is a graph showing the relationship between vulcanization time and tire temperature. It is a line diagram showing a relationship. 4.--Tire base, 7.--.Insulation cylinder sheet, 9-.--Insulation cylinder section, M.--.
center of the tire. Usum Patent Applicant Sumitomo Rubber Industries Co., Ltd. Agent
Patent Attorney Tadashi Naemura 5th 6th m IO Month 26, 1988 3. Relationship with Hanyu, the person making the amendment Address of the original address: 1-1-1 Tsutsui-cho, Chuo-ku, Kobe Name: Sumitomo Rubber Industries, Ltd. Representative: Katsura 1) Representative: Katsura 4, agent address: Osaka Juseiyo-ku Nishi No. 2-26 Nakajima 4-chome 6° Subject of amendment (1) "Insulating rubber" on page 6, line 4 of the specification is amended to "insulating silane rubber." (2) rH2/H1 on page 7, lines 9 to 17 of the specification
-... range. ”, rH2/H1 is 0.005
or more and 0.7 or less, preferably 0.1 or more and 0.5
or less, and the ratio H3/H1 between the intermediate height H3 and the tire cross-sectional height Hl is 0.2 or more and 0.65 or less,
It is preferably 0.3 or more and 0.55 or less, and the width W2 of the insulation run part 9 and the intermediate height (H
The ratio W2/Wl to the tire width W1 at 1/2) is 0.
The range is 3 or more and 0.8 or less. ” he corrected. (3) Table 1 between pages 9 and 10 of the specification is amended as shown in the attached sheet. (4) Correct the 6th drawing of the drawing as shown in the attached sheet. (Add code) 8. List of attached documents (1) Amended Table 1 1 copy (
2) Figure 6 of the corrected drawings 1 copy, Table 1

Claims (1)

[Claims] 1. Manufacture of a solid tire characterized in that an insulation part having a rubber having a faster vulcanization rate than the rubber forming the tire base is provided inside the tire base in the circumferential direction of the tire. Method. 2. The method of manufacturing a solid tire according to claim 1, wherein the insulation portion is formed by winding an insulation sheet made of rubber that has a faster vulcanization rate than the rubber of the tire base.