JPS6233627A - Tire manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing tires, particularly a method for manufacturing tires such as pneumatic tires and solid tires, which improves the workability of manufacturing and improves the tire appearance. Regarding.

(Prior Art) Generally, tires such as pneumatic tires and solid tires are manufactured by press-curing a molded green tire. The mold used in this case has a diameter of 0.5 to 2.0 mm in order to prevent air bubbles from forming at the interface between the mold and the green tire during vulcanization, or to prevent air bubbles from remaining inside the tire. Many vent holes are provided, and so-called spills, which flow into the vent holes and harden, remain on the vulcanized tire surface.

Therefore, it is necessary to remove this with a knife, scissors, or the like. Further, when the tire is removed from the mold after vulcanization, the spill may be cut from the root near the tire surface, and the spill may become clogged in the vent hole, which must be removed. The work required to remove such spills occupies a large portion of the time required for the tire vulcanization process and finishing process, causing a significant decrease in productivity.

On the other hand, in recent years, pneumatic tires have moved away from the conventional idea that tires should be strong and last a long time, to the point where user needs have diversified and demands for fashionability, especially when it comes to spouts that remain on the sidewalls of tires. Removal marks were sometimes a problem.

In order to improve the above problems, it would be good to eliminate the spill from the vulcanized tire, but for example, a method of vulcanizing a solid tire without providing a vent hole in the mold is disclosed in Japanese Patent Application Laid-Open No. 59-103736. It is stated in the No. According to this method, the green tire has a Mooney viscosity (MLl) of
, 4 t3o℃) is 48 or less and scorch time t,
. It is said that by adjusting the (min) to 25 or less, a so-called spiuleless solid tire can be manufactured. However, especially in the case of pneumatic tires, the tread, sidewall, bead, and other components each have different required properties, so the rubber compositions used for these components also have completely different properties. . Therefore, it is difficult to construct all parts of a tire from a rubber composition having the above-mentioned Mooney viscosity and scorch time, and even if it were possible, it would have the disadvantage of having to sacrifice each required characteristic. there were. It is also possible to reduce the diameter of the vent hole to the limit that causes bare particles, etc., resulting in a shorter spill length, and in some cases, it is possible to almost omit the work of removing spills from the tire surface. However, in this case, the diameter of the spiule is too small, so when the tire is removed from the mold, the spiule is cut from the root and remains in the vent hole, which significantly increases the time required to remove the spiule from the vent hole. It had drawbacks.

(Problems to be Solved by the Invention) A method for manufacturing a tire with improved appearance by improving or omitting vulcanization workability and finishing workability without impairing tire performance or worsening product defect rate. It is the problem that the present invention seeks to solve.

(Means for solving the problem) The present inventors have disclosed in Japanese Patent Application No. 59-240930 and Japanese Patent Application No. 60-92186 that a nitroso compound or a monomaleimide compound is kneaded into the polymer main chain. A method for partially curing an unvulcanized rubber surface by applying a dihalide to the surface of an unvulcanized rubber composition reacted in a step was provided. On the other hand, the phenomenon of rubber flowing into the vent hole is caused by the rubber flowing due to the pressure during vulcanization, so if the rubber flow is suppressed, the length of the spill can be shortened or no spill can occur at all. is possible.

That is, it was confirmed that the above-described method of partially curing the surface of unvulcanized rubber can be used as a method of preventing rubber from flowing into the vent hole, and the present invention was achieved.

That is, the present invention provides a method for producing a tire that includes a tread portion, a pair of sidewall portions connected to the tread portion at both shoulders of the tread portion, and a pair of bead portions formed on the inside of the sidewall portions. , with respect to 100 parts by weight of at least one rubber selected from the group consisting of natural rubber and diene-based synthetic rubber, the general formula (wherein R8 and R2 are each a hydrogen atom and carbon number 1 to
6 represents an alkyl group, a hydroxyalkyl group, a cycloalkyl group, or an aryl group. ) and (wherein, when R3=R4,
Both represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and when R:1=R4, R3 is a hydrogen atom,
R4 represents a phenyl group. ) An aromatic amine compound-containing unvulcanized product containing 0.1 to 5.0 parts by weight of at least one aromatic amine compound selected from the group consisting of monomaleimide aromatic amine compounds represented by The rubber composition constitutes at least the surface portion of at least one of the tire members including the tread portion, sidewall portion, and bead portion, and the thus obtained component is used as an outer surface of other tire members. Before or after forming a tire in combination with A method for producing a tire is characterized in that a molded tire is obtained by applying at least one of the following to the surface of the tire and partially cured, and then the molded tire is vulcanized and cured in a press.

In the present invention, diene-based synthetic rubbers include synthetic polyisoprene rubber (IR), polybutadiene rubber, styrene-butadiene rubber, ethylene-propylene terpolymer, butyl rubber, halogenated phthyl rubber, acrylonitrile rubber,
Butadiene rubber, etc., and may be used alone or in a blend.

In the present invention, as a specific example of the nitroso aromatic amine compound, N,N-dimethyl-p-nitrosoaniline (D
MNA), N,N-diethyl-p-nitrosoaniline (
DENA), N-phenyl-p-nitrosoaniline (P
NA), N,N-dibutyl-p-nitrosoaniline (D
BNA), N-methyl-N-hexyl-p-nitrosoaniline, N,N-di-2-hydroxyethyl-p-nitrosoaniline, N-ethyl-N-2-hydroxyethyl-p-nitrosoaniline (E) INA), N-methyl-
p-nitrosoaniline (MNA), N-hexyl-p-
Nitrosoaniline (HNA) and N-cyclohexyl-
p-nitrosoaniline (CHNA), and these may be used alone or in combination. In addition, when conducting the tests shown in the examples, commercially available nitroso compounds are used, or known synthetic methods (G.
Willenz) Journal of the Chemical Society (J, Chem, Soc, +1955,
P1677) was used.

Specific examples of monomaleimide aromatic amine compounds used in the present invention include, for example, N-(p-N',
N'-dimethylaminophenyl)maleimide (DMMI
).

N-(p-N', N'-diethylaminophenyl)
Maleimide (old DE), N-(ρ-N', N'-dipropylaminophenyl)maleimide (1) PMI), N
-(p-N', N''-dibutylaminophenyl)maleimide (old DB), N-p-aminophenylmaleimide (
(APMI), N-(p-N''-anilinophenyl)maleimide (PAPMI), and the like, and these may be used alone or in combination of two or more.

Furthermore, when conducting the tests shown in Examples, monomaleimide aromatic amine compounds were used either as commercially available products or synthesized according to known synthesis methods.

Further, a nitroso aromatic amine compound and a monomaleimide aromatic amine compound may be used together. Here, the blending amount of the nitroso aromatic amine compound and the monomaleimide aromatic amine compound is 0 to 100 parts by weight of the rubber.
．． It is 1 to 5.0 parts by weight.

If the amount is less than 0.1 parts by weight, there is no effect of improving green strength or green modulus, and it is not sufficient to partially cure the unvulcanized rubber surface, and if it exceeds 5.0 parts by weight, the effect of increasing the amount will simply disappear. Moreover, it is not suitable because it also has a negative effect on various physical properties after vulcanization.

Constituting at least the surface portion of at least one tire member such as the tread portion, sidewall portion, and bead portion with these aromatic amine compound-containing unvulcanized rubber compositions means that, in the maximum case, the whole tire member itself is It may be composed of the unvulcanized rubber composition, or in the minimum case, only a very thin surface portion may be composed of the unvulcanized rubber composition.

As a method for forming a portion of the tire member including the surface portion with the unvulcanized rubber composition, a coating method, a diffusion method, or a combination method thereof can be used. A preferred method is to create a thick rubber sheet and laminate this rubber sheet to the remainder of the target tire member. In this case, the tire is molded by combining it with other tire members so that the side to which the rubber sheet is pasted is the outer surface of the tire. The thickness of such an unvulcanized rubber sheet is preferably 0.1 to 3 mm.

If the thickness is less than 0.1 mm, the effect of shortening the spill length will not be sufficient, and if it exceeds 3 mm, the coating workability will deteriorate, which is not preferable.

In the present invention, a halide is applied to the surface of an unvulcanized rubber member blended with the above-mentioned nitroso aromatic amine compound or monomaleimide aromatic amine compound, and in this case, ether or chloroform is used.

Isopropyl alcohol, benzene, toluene.

Methods used include dissolving it at an appropriate concentration in an appropriate solvent such as rubber volatile oil and applying it to the rubber surface using a brush or roll, spraying it by spraying, or immersing it in a solution containing a halide. However, any other method may be used as long as the purpose of the present invention is not impaired. In such a case, the optimum concentration of the halide solution varies depending on the coating method, but is preferably 1 to 50% by weight.

However, this concentration is not particularly important and will vary depending on conditions such as the coating method and the expected degree of partial curing. It can have the same effect as the case. In this way, an unvulcanized tread member, a sidewall member, in which a halide is blended with a nitroso aromatic amine compound and/or a monomaleimide aromatic amine compound,
Alternatively, after applying it to the surface of the bead member and partially curing the rubber surface, a tire is molded and vulcanized. Also,
Before applying the halide, the member may be molded to create a green tire, and then the halide may be applied by the method described above.

In addition, when laminating the unvulcanized rubber sheets together to form a tire component, it is possible to coat at least two surfaces of the rubber sheet with a halide in advance, expose the coated surface, and attach it to the rest of the component. However, the coating before lamination may be omitted and the above-mentioned coating may be performed after lamination.

Specific examples of halides include α,α゛-dibromo-p-xylene (BPX), α,α゛-dibromo-m-xylene (BMX), α,α''-dibromo-
Xylene (BOX), α, α”-dibromo-p-diethylbenzene (BPEB), α, α, α”, α゛-tetrabromo-p-xylene TBPX), α, α, α゛, α
”-Tetrabromo-m-xylene (TBMX), α, α
, α”, α′-tetrabromo-0-xylene (TBOX
), α, α”-dichloro-p-xylene (CPX), α
, α゛-dichloro-m-xylene (CMX), α, α°
-dichloro--xylene (COX), etc., and these may be used alone or in combination of two or more. Note that the halides used in the examples of the present invention are commercially available products.

In addition, in the present invention, the above-mentioned aromatic amine compound and halide are reacted at room temperature to form a quaternary ammonium salt through ionic bonding.
If the heat treatment is carried out at a temperature of about 100,000 yen, it is possible not only to shorten the standing time until curing, but also to reduce variations in the degree of partial curing due to changes in season and temperature.

In addition to the above-mentioned aromatic amine compounds and halides, the present invention uses compounding agents commonly used in the rubber industry, such as reinforcing fillers, softeners, anti-aging agents, vulcanization accelerators, and vulcanization accelerators. , a vulcanizing agent, etc. can be blended into the rubber as needed within the usual blending amounts.

(Examples) Next, the present invention will be described in more detail with reference to Examples, Reference Examples, and Comparative Examples.

Soukoflame N, N-dibutyl-p-nitrosoaniline (DBNA)
Synthesis of N,N-dibutylaniline 51.3g (0.25 mol)
, 200 g of water and 105 m of concentrated hydrochloric acid t! 9 to a mixed solution of
Dissolve 18.5 g (0.26 mol) of 7% pure sodium nitrite in 30 ml of water? The solution was added dropwise at 5 to 10°C over a period of 30 minutes without stirring. 1 at 10-20℃
After stirring for an hour, add 15% caustic soda aqueous solution p)
! - Neutralized up to 8. The obtained crystals were filtered, washed well with water on a filter paper, and then dried with hot air at 50°C for 48 hours to obtain a crystal of 122-1.
N with a melting point of 24°C.

28.1 g (yield 48.0%) of N-dibutyl-p-nitrosoaniline was obtained.

N-Ethyl-N-2-hydroxyethylaniline 41.
3 g (0.25 mol), 200 g of water and 105 m of concentrated hydrochloric acid
18.5 g of 97% pure sodium nitrite in a mixed solution of
(0.26 mol) dissolved in 30 mβ of water, 5 to 1
The mixture was added dropwise at 0°C for 30 minutes while stirring. 10～
After stirring at 20°C for 1 hour, the mixture was neutralized to pH 8 with a 15% aqueous solution of caustic soda.

Next, 100 mA of benzene was added to the reaction solution and the mixture was stirred, left to stand, and the organic phase was separated. Benzene in the obtained organic phase was concentrated under reduced pressure to obtain 28.9 g (yield 59.6%) of N-ethyl-N-2-hydroxyethyl-p-nitrosoaniline as a dark brown viscous liquid.

Synthesis of N-methyl-p-nitrosoaniline (MNA) 4
1 N-methylaniline in methyl alcohol containing 0% hydrochloric acid
07g (1.0 mol) was added dropwise to the resulting solution at 5-10°C over 1.5 hours with stirring to give a concentration of 97% at 5°C.
80 g (1.12 mol) of pure sodium nitrite were added.

Further, after stirring at 15 to 25°C for 15 hours, the reaction solution was added to ice water in Step 22, stirred for 15 minutes, and then neutralized to pH 8 with aqueous ammonia. Next, 500ml of heptane
After stirring at 10-20°C for 2 hours, the formed crystals were filtered, washed well with water on filter paper, and stirred at 50°C for 48 hours.
69.5 g of N-methyl-p-nitrosoaniline (yield: 51.1
%) was obtained.

By performing the same operation as in Reference Example 3 except that 177 g (1.0 mol) of N-n-hexylaniline was used instead of N-methylaniline, N- having a melting point of 46 to 48°C was obtained. 99.5 g of n-hexyl-p-nitrosoaniline (
A yield of 48.3%) was obtained.

By performing the same operation as in Reference Example 3 except that 175 g (1.0 mol) of N-cyclohexylaniline was used instead of N-methylaniline, N-cyclohexyl- p-Nitrosoaniline 84.1g
(yield 41.2%).

Reference example 6 2 equipped with a reflux condenser, thermometer, and stirrer with mercury seal
1. To the fourth flask, add 400 ml of acetone and p-N.
, N-dimethylaminoaniline 102.1 g (0,75
Maleic anhydride (84 mol) was added to the resulting solution.
．． A solution of 6 g dissolved in 250 ml of acetone was added dropwise at room temperature over 2 hours, and the mixture was further stirred at 50°C for 1 hour. Next, after cooling to room temperature, 191% of acetic anhydride was added.
3g (1,875 mol) and 18.5g sodium acetate
(0,225 mol) and again at 50° to 60°C.
The reaction was completed by stirring for an hour. After cooling to room temperature, add 60% water
0 ml was added little by little to crystallize the target product, filtered, washed well with water on filter paper, and dried with hot air at 50°C for 48 hours to have a melting point of 153.5'~154.5°C. N-(p-N”.

N-dimethylaminophenyl)maleimide 136.2
g (yield -84, 1%) was obtained.

p''■tsuL p-N, p-N instead of N-dimethylaminoaniline,
By performing the same operation as in Reference Example 1 except that 165 g (0.75 mmol) of N-dibutylaniline was used, 73
．． N-(p-N', N
”-dibutylaminophenyl)maleimide 231g (
A yield of 77.0% was obtained.

Synthesis of p-N, instead of N-dimethylaminoaniline, p-
By carrying out the same operation as in Reference Example 1 except using 138 g (0.75 mol) of aminodiphenylamine, 16
219 g (yield=83.0%) of N-(4-anilinophenyl)maleimide having a melting point of 1° to 163° C. was obtained.

Examples 1 to 9, Upper Axis Examples 1 to 3 50 parts by weight of FEF carbon black was added to 100 parts by weight of rubber consisting of 50 parts by weight of natural rubber and 50 parts by weight of polybutadiene rubber.
Parts by weight, 15 parts by weight of aroma oil, 1.5 parts by weight of stearic acid
Parts by weight, N-(1,3-dimethylbutyl") -N'-
2.5 parts by weight of phenyl-ρ-phenylenediamine and the first
After kneading 1.0 parts by weight of the nitroso aromatic amine compound or 2.0 parts by weight of the monomaleimide aromatic amine compound shown in the table for 4 minutes in a Banbury mixer, the kneaded product was taken out, and after cooling, an additional 3 parts by weight of zinc white was mixed. , 0.5 parts by weight of N-oxydiethylene-2-benzothiazolesulfenamide, and 2.0 parts by weight of sulfur to prepare an unvulcanized rubber composition. When a monomaleimide aromatic amine compound was used, 1.0 parts by weight of dibenzothiazyl disulfide was used simultaneously with the monomaleimide aromatic amine compound. The obtained unvulcanized rubber composition was molded into a tire size 185/7.
The sidewall of the 0SR13 tire is divided into four parts,
For example, Comparative Example 1 is a sidewall that does not contain any aromatic amine compound and no halide is applied, Comparative Example 2 is a sidewall that is coated with a halide, and MNA is mixed as a nitroso compound. Green tires were prepared as Comparative Example 3 in which no halide was applied, and Example 1 in which MNA was blended as a nitroso compound and a halide was applied. At this time, the halide was applied to predetermined locations after the green tire was molded. After this green tire was left for a day and night, it was press-vulcanized using a mold provided with two types of vent holes, each having a diameter of 1.5 mm and 0.5 mm. The tire was removed from the mold, and the length of each spew was measured and averaged. The results are shown in Table 1.

As is clear from Table 1, according to the tire manufacturing method of the present invention shown in the Examples, the spill length was significantly shortened, and it was possible to omit the spill removal operation.

Comparative Examples 4 to 6 Unvulcanized rubber compositions were prepared in the same manner as in Examples 1 to 9, but using the aromatic amine compounds in Table 2 instead of the aromatic amine compounds in Table 1. A rubber sheet with a thickness of 0.8 mm was prepared from this. In addition, when a monomaleimide aromatic amine compound was used as the aromatic amine compound, 1.0 parts by weight of dibenzothiazyl disulfide was used together with this compound.

Next, the halides shown in Table 2 were dissolved in toluene at a concentration of 2.5% and applied to the upper surface of the rubber sheet. Green strength (Tb) and green modulus (gate 1°) were measured. The outer surface of the sidewall of a tire size 185/70SR13 was divided into four parts, and, for example, a rubber sheet containing no aromatic amine compound was coated with no halide in Comparative Example 4, and a halide was coated on the rubber sheet. Comparative Example 5 is a case in which MNA is blended as a nitroso compound but no halide is applied, and Example 10 is a case in which a halide is coated on a rubber sheet containing MNA as a nitroso compound. Coat it to create a raw tire,
Press vulcanization was performed using a mold provided with two types of hent holes, each having a diameter of 1.5 mm and 0.5 mm. The tire was removed from the mold, and the length of each spew was measured and averaged. The results are shown in Table 2.

As is clear from Table 2, according to the tire manufacturing method of the present invention shown in the Examples, the spiule length was significantly shortened, making it possible to omit the spiew removal operation.

(Effects of the Invention) As described above, the present invention provides an unvulcanized rubber composition containing a specific aromatic amine compound for at least the surface of at least one tire member of the tread portion, sidewall portion, and bead portion. A method for manufacturing a tire with improved appearance by improving or omitting vulcanization work and finishing workability without impairing tire performance by applying a specific halide to the surface of the tire. can be provided.

Claims (1)

[Claims] 1. Manufacture a tire comprising a tread portion, a pair of sidewall portions connected to the tread portion at both shoulders of the tread portion, and a pair of bead portions formed on the inside of the sidewall portions. To do this, a general formula ▲ mathematical formula, chemical formula, table, etc. is provided for 100 parts by weight of at least one rubber selected from the group consisting of natural rubber and diene-based synthetic rubber ▼ (in the formula, R_1 and R_2 are There are nitroso aromatic amine compounds represented by a hydrogen atom, an alkyl group or hydroxyalkyl group having 1 to 6 carbon atoms, a cycloalkyl group, or an aryl group, respectively. , R_3=R_4, both represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R_3=R
When it is not _4, R_3 represents a hydrogen atom and R_4 represents a phenyl group. ) An aromatic amine compound-containing unvulcanized product containing 0.1 to 5.0 parts by weight of at least one aromatic amine compound selected from the group consisting of monomaleimide aromatic amine compounds represented by The rubber composition constitutes at least the surface portion of at least one of the tire members including the tread portion, sidewall portion, and bead portion, and the thus obtained component is used as an outer surface of other tire members. Before or after forming a tire in combination with the general formula ▲ mathematical formula, chemical formula, table, etc. ) A molded tire is obtained by applying at least one type of halide represented by the formula to the surface and partially curing the molded tire, and then the molded tire is vulcanized and cured in a press. Method.