CN113045806A

CN113045806A - Rubber formula capable of shortening length of tire rubber

Info

Publication number: CN113045806A
Application number: CN202110373044.9A
Authority: CN
Inventors: 杨一杰; 林添益
Original assignee: Cheng Shin Rubber Xiamen Ind Ltd
Current assignee: Cheng Shin Rubber Xiamen Ind Ltd
Priority date: 2021-04-07
Filing date: 2021-04-07
Publication date: 2021-06-29
Anticipated expiration: 2041-04-07
Also published as: CN113045806B

Abstract

The invention provides a rubber formula capable of shortening the length of tire rubber, which comprises 60-85 parts of diene rubber, 15-40 parts of brominated isobutylene-p-methylstyrene copolymer, 20-80 parts of reinforcing filler, 1-8 parts of zinc oxide, 0.5-3 parts of stearic acid, 0.5-10 parts of anti-aging agent, 0.5-30 parts of processing oil, 0.5-10 parts of vulcanizing agent and 0.5-10 parts of vulcanization accelerator, wherein the reinforcing filler is carbon black and can be composed of carbon blacks with two different particle sizes. The rubber formula provided by the invention can ensure tensile property, reduce the fluidity of rubber materials, effectively shorten the length of the crude rubber after tire vulcanization, and improve the condition that the crude rubber breaks and blocks crude rubber holes.

Description

Rubber formula capable of shortening length of tire rubber

Technical Field

The invention relates to the technical field of tire rubber formulas, in particular to a rubber formula capable of shortening the length of tire rubber.

Background

The existing tire formula mostly uses diene rubber as a matrix, local poor vulcanization caused by broken crude rubber blocking crude rubber holes is easy to occur in the production process, and the crude rubber is too long and easy to break mainly due to the fact that the existing tire rubber material is high in fluidity and insufficient in tensile strength. At present, the flowability of the rubber compound is usually reduced by means of process adjustment, for example, the plasticity of the rubber compound is controlled during mixing, and the vulcanization temperature, pressure, time and the like are controlled during vulcanization, so as to achieve the purposes of shortening the length of the raw rubber and reducing the breakage of the raw rubber. However, this method requires no additional disadvantages to be avoided during adjustment, and therefore the adjustment of the flowability of the compound is limited.

Therefore, the research and improvement of the invention aims to develop a rubber formula capable of shortening the length of the tire rubber.

Disclosure of Invention

Aiming at the problems, the invention provides a rubber formula capable of shortening the length of tire rubber, which can ensure the tensile property, reduce the fluidity of rubber materials, effectively shorten the length of the vulcanized tire rubber and improve the condition that the rubber holes are blocked by the broken tire rubber.

The technical scheme of the invention is as follows:

a rubber formula capable of shortening the length of tire rubber comprises the following components in parts by mass: 60-85 parts of diene rubber, 15-40 parts of brominated isobutylene-p-methylstyrene copolymer, 20-80 parts of reinforcing filler, 1-8 parts of zinc oxide, 0.5-3 parts of stearic acid, 0.5-10 parts of anti-aging agent, 0.5-30 parts of processing oil, 0.5-10 parts of vulcanizing agent and 0.5-10 parts of vulcanization accelerator, wherein the reinforcing filler is carbon black.

Further, the reinforcing filler includes a first particle size carbon black and a second particle size carbon black, the first particle size carbon black having an average particle size smaller than that of the second particle size carbon black.

Further, the average particle diameter of the carbon black with the first particle diameter is 20nm to 45nm, and the average particle diameter of the carbon black with the second particle diameter is 46nm to 110 nm.

Further, the first particle size carbon black comprises one or any combination of the following: n110, N121, N134, N220, N231, N234, N242, N293, N299, N315, N326, N330, N332, N339, N343, N347, N351, N358, N375;

the second particle size carbon black comprises one or any combination of the following: n539, N550, N582, N630, N642, N650, N660, N683.

Further, the mass ratio of the carbon black with the first particle size to the carbon black with the second particle size is 4-9: 1.

Further, the diene rubber comprises one of the following or any combination thereof: natural rubber, styrene-butadiene copolymer, polybutadiene rubber.

The invention has the beneficial effects that the brominated isobutylene-p-methylstyrene copolymer (hereinafter referred to as BIMSM) with a proper amount is added into the rubber formula, and the ratio of the carbon black with smaller particle size to the carbon black with larger particle size in the rubber formula is optimized, so that the tensile property is ensured, the fluidity of the rubber material is reduced, the length of the crude rubber after the tire is vulcanized is effectively shortened, the condition that the crude rubber is broken to block the crude rubber holes is improved, the reject ratio of products is reduced, the appearance of the tire is improved, and the production efficiency is improved.

Detailed Description

The present invention will be further illustrated below with reference to specific examples and comparative examples.

Example one

In the embodiment, the rubber formula comprises 55 parts of No. 5 standard natural rubber (hereinafter referred to as "NR-5"), 45 parts of BIMSM, 50 parts of reinforcing filler and auxiliary components, wherein the auxiliary components comprise 3 parts of zinc oxide, 2 parts of stearic acid, 4 parts of anti-aging agent, 10 parts of processing oil, 2 parts of vulcanizing agent and 1.8 parts of vulcanization accelerator, and the reinforcing filler adopts N330 carbon black.

Example two

The difference between this example and the first example is that in this example, the rubber formulation contains 60 parts of NR-5 and 40 parts of BIMSM.

EXAMPLE III

The difference between the rubber formulation of this example and the first example is that, in this example, NR-5 is 70 parts and BIMSM is 30 parts.

Example four

The difference between this example and the first example is that in this example, the rubber formulation contains 85 parts of NR-5 and 15 parts of BIMSM.

EXAMPLE five

The difference between this example and the first example is that in this example, the rubber formulation contains 90 parts of NR-5 and 10 parts of BIMSM.

EXAMPLE six

The difference between this example and the first example is that, in this example, the rubber formulation contains 70 parts of NR-5, 30 parts of BIMSM, and the reinforcing filler is composed of 45 parts of carbon black with a first particle size and 5 parts of carbon black with a second particle size, where the carbon black with the first particle size is N330 carbon black and the carbon black with the second particle size is N550 carbon black.

EXAMPLE seven

The difference between this example and the first example is that, in this example, the rubber formulation contains 70 parts of NR-5, 30 parts of BIMSM, 40 parts of carbon black with a first particle size and 10 parts of carbon black with a second particle size, wherein the carbon black with the first particle size is N330 carbon black, and the carbon black with the second particle size is N550 carbon black.

Example eight

This example differs from example one in that in the rubber formulation of this example, the rubber formulation contains 70 parts NR-5, 30 parts BIMSM, and the reinforcing filler is composed of 35 parts carbon black of the first particle size and 15 parts carbon black of the second particle size, the carbon black of the first particle size is N330 carbon black, and the carbon black of the second particle size is N550 carbon black.

Example nine

The difference between this example and the first example is that, in this example, the rubber formulation contains 70 parts of NR-5, 30 parts of BIMSM, and the reinforcing filler is composed of 30 parts of carbon black with a first particle size and 20 parts of carbon black with a second particle size, where the carbon black with the first particle size is N330 carbon black and the carbon black with the second particle size is N550 carbon black.

Comparative example 1

This comparative example differs from example one in that in this comparative example, the rubber formulation contains 100 parts of NR-5 and no BIMSM.

Performance effect test

According to the rubber formulations of examples one to nine and comparative example one, accelerated rubber compounds, vulcanized test pieces and tires were prepared by the following procedure. The component pair ratios of the rubber formulations are shown in table 1.

TABLE 1 comparison of rubber formulation Components for example one to example nine and comparative example one

(1) Preparation of accelerated rubber mixes

Preparation of unprimed rubber mixes: firstly, putting NR-5 and BIMSM into an internal mixer for mixing for 1min by adopting the internal mixer, setting the initial temperature to be 60 ℃, the rotating speed to be 60r/min and the pressure to be 0.5 MPa; secondly, putting zinc oxide, stearic acid, an anti-aging agent, 1/2 processing oil and 1/2 reinforcing filler into an internal mixer for mixing for 1 min; then, the rest reinforcing filler and processing oil are put into an internal mixer for mixing for 1 min; finally sweeping and mixing to the glue temperature of 155 ℃ and discharging.

Preparation of a boosting rubber compound: an internal mixer is adopted, the initial temperature is set to be 60 ℃, the rotating speed is set to be 20r/min, the pressure is set to be 0.5MPa, rubber which is not added with accelerator is firstly put into the internal mixer for mixing for 20 seconds, then a vulcanizing agent and a vulcanization accelerator are put into the internal mixer for mixing for 1min for cleaning, and then the internal mixer is mixed until the rubber temperature is 100 ℃ for discharging.

(2) Preparation of vulcanized test piece

Adding accelerating rubber compound on an open mill, adjusting the roll gap to be 0.5mm, thinly passing for 3-4 times, discharging the rubber compound with the roll gap of 2mm, placing for 4-8 hours, and vulcanizing in a flat vulcanizing machine at the vulcanizing temperature of 160 ℃ for 10min to obtain a vulcanized test piece.

(3) Preparation of tires

And preparing the accelerating rubber compound into the tire according to the existing tire production process.

1. Tensile Property test

The tensile strength at break and the elongation at break were measured at room temperature according to GB/T528 standard, and the results are expressed as relative indices, taking the vulcanized test pieces prepared according to the rubber formulations of examples one to nine and comparative example one. A larger value of the relative index of the tensile strength at break to the elongation at break indicates a better tensile property.

2. Sizing flowability test

The rubber formulations of examples one to nine and comparative example one were used to prepare accelerated rubber mixes, which were tested for shear viscosity by capillary rheometry and the results are expressed as relative indices. A higher value of the shear viscosity relative index indicates a lower shear viscosity and a higher fluidity.

3. Gross rubber Length test

The average gross rubber length of the finished tires prepared according to the rubber formulations of examples one to nine and comparative example one was measured and expressed as a relative index. A larger number of average strand lengths relative to the index indicates a shorter strand length.

4. Gross rubber hole plugging test

Tire molds after tires were prepared according to the rubber formulations of examples one to nine and comparative example one were observed to determine the degree of clogging of the gross rubber holes in a graded manner. The degree of clogging was evaluated by the gross rubber hole clogging rate, which is the clogging hole number/total gross rubber hole number 100%, and defined as a gross rubber hole clogging rate of not more than 5% in 1 stage, not more than 15% in 2 stage, and not more than 15% in 3 stage.

The results of the tensile properties, compound flow, gum length, gum hole plugging test items for the rubber formulations of examples one-nine and comparative example one are shown in table 2.

TABLE 2 results of the Performance test of the rubber formulations of examples one to nine and comparative example one

Compared with the first comparative example, the mobility of the rubber material can be reduced by adding the BIMSM, the mobility of the rubber material is reduced along with the increase of the using amount of the BIMSM, the average length of the crude rubber is reduced, the blocking condition of crude rubber holes is improved, but the tensile strength and the tensile elongation of the rubber material are reduced to a certain extent, so that the proportion of the BIMSM is set to 15-40 parts, and the aims of shortening the length of the crude rubber and improving the blocking condition of the crude rubber holes can be fulfilled on the premise of considering the tensile property, the mixing operability in the production process and the cost.

Examples three and six-nine rubber formulations each had a reinforcing filler comprised of a first particle size carbon black, N330, and a second particle size carbon black, N550, wherein the particle size of the N330 carbon black is less than the particle size of the N550 carbon black. When the N550 carbon black with larger particle size is lower in the whole reinforcing filler, along with the increase of the using amount of the N550 carbon black, a small amount of the N550 carbon black and the N330 carbon black are compounded, and the carbon black is aggregated to widen the particle size range of aggregates, which is beneficial to the dispersion of the N330 carbon black accounting for a larger proportion in the reinforcing filler, so that the tensile strength at break and the elongation at break of the rubber compound are increased, but the fluidity of the rubber compound is increased to a certain extent, the average length of the crude rubber is increased, and the blocking condition of crude rubber holes is deteriorated to a certain extent. As the amount of N550 carbon black continues to increase, the tensile strength at break and the elongation at break of the compound decrease because the larger particle size carbon black has better dispersibility in the compound than the smaller particle size carbon black, but the reinforcing property decreases. Therefore, the mass ratio of the N330 carbon black with the smaller particle size to the N550 carbon black with the larger particle size is set to be 4-9: 1, and the tensile strength at break and the elongation at break can be improved on the premise of shortening the rubber length as much as possible and improving the blocking condition of rubber holes.

According to the invention, through adding BIMSM into the diene rubber and simultaneously optimizing the ratio of carbon black with smaller particle size to carbon black with larger particle size in the rubber formula, the tensile property is ensured, the fluidity of the rubber material is reduced, and the length of the crude rubber after vulcanization of the tire is effectively shortened, so that the condition that the crude rubber is broken to block the crude rubber holes is improved, the product reject ratio is reduced, the appearance of the tire is improved, and the production efficiency is improved.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The rubber formula capable of shortening the length of the tire rubber is characterized by comprising the following components in parts by mass: 60-85 parts of diene rubber, 15-40 parts of brominated isobutylene-p-methylstyrene copolymer, 20-80 parts of reinforcing filler, 1-8 parts of zinc oxide, 0.5-3 parts of stearic acid, 0.5-10 parts of anti-aging agent, 0.5-30 parts of processing oil, 0.5-10 parts of vulcanizing agent and 0.5-10 parts of vulcanization accelerator, wherein the reinforcing filler is carbon black.

2. A rubber formulation for reducing the length of tire bead filler in accordance with claim 1, wherein said reinforcing filler comprises a first particle size carbon black and a second particle size carbon black, said first particle size carbon black having an average particle size less than said second particle size carbon black.

3. The rubber formulation for shortening the length of the tire rubber according to claim 2, wherein the first carbon black has an average particle size of 20nm to 45nm, and the second carbon black has an average particle size of 46nm to 110 nm.

4. A rubber formulation capable of shortening the length of tire unvulcanized rubber according to claim 3, wherein said first particle size carbon black comprises one or any combination of the following: n110, N121, N134, N220, N231, N234, N242, N293, N299, N315, N326, N330, N332, N339, N343, N347, N351, N358, N375;

5. A rubber formulation capable of shortening the length of a tire unvulcanized rubber according to any one of claims 3 to 4, wherein the mass ratio of the carbon black with the first particle size to the carbon black with the second particle size is 4-9: 1.

6. A rubber formulation for shortening the length of green tire rubber according to claim 1, wherein said diene rubber comprises one or any combination of the following: natural rubber, styrene-butadiene copolymer, polybutadiene rubber.