CN114032026A

CN114032026A - High-hardness anti-sticking tire mold and preparation method and application thereof

Info

Publication number: CN114032026A
Application number: CN202111231728.1A
Authority: CN
Inventors: 潘文; 朱立新; 杨全林; 冯兴林; 杜国峰; 李洪飞; 李波; 李放
Original assignee: Shandong Changfeng Tire Co ltd
Current assignee: Shandong Changfeng Tire Co ltd
Priority date: 2021-10-22
Filing date: 2021-10-22
Publication date: 2022-02-11

Abstract

The invention provides a high-hardness anti-sticking tire mold, a preparation method and application thereof, wherein the high-hardness anti-sticking tire mold comprises the following components: the anti-sticking tire mold comprises a tire mold base body and an anti-sticking layer, wherein a rough contact surface is arranged between the tire mold base body and the anti-sticking layer; the anti-sticking layer comprises one or more of bicomponent addition silica gel, submicron SiC, a surfactant and octamethyl octasilsesquioxane. The novel anti-sticking coating for the tire mold, which is prepared by the invention, has low friction force and low surface energy, and has more excellent anti-sticking performance compared with the existing polytetrafluoroethylene coating. According to the invention, through a sand blasting process and sand treatment with a specific mesh number, the bonding degree of the anti-sticking layer and the tire mold matrix is higher. The tire mold disclosed by the invention is high in hardness, high in demolding rate and long in service life in the tire preparation process, especially in the preparation process of the semisteel radial tire CH-268.

Description

High-hardness anti-sticking tire mold and preparation method and application thereof

Technical Field

The application relates to the technical field of tire molds, in particular to a high-hardness anti-sticking tire mold and a preparation method and application thereof.

Background

In the molding operation of the rubber tire, the mold is a final shaping tool, and with the rapid development of modern industry, people have higher and higher requirements on the performance of the surface of the tire mold, improve the surface performance of materials, effectively prolong the service life of products, improve the productivity, save resources and reduce the environmental pollution; in order to prolong the service life of mechanical parts, researchers at home and abroad widely perform research on material surface modification technology, and in order to reduce cost, a coating is generally adopted as a surface modification method.

Polytetrafluoroethylene (PTFE), also known as plastron, is a polymer made by polymerizing Tetrafluoroethylene (TFE) as a monomer. PTFE is the most used fluoroplastic, and the amount of PTFE consumed worldwide each year accounts for about 70% of the total amount of fluorocarbon resin. PTFE has high chemical stability, acid and alkali resistance, non-stickiness, lubricity, corrosion resistance and excellent aging resistance, and is widely applied to fluorocarbon anticorrosive coatings. Therefore, at present, polytetrafluoroethylene is generally used as a mold coating because of its advantages of small friction coefficient, good corrosion resistance and the like, but polytetrafluoroethylene has low hardness and very poor wear resistance, and is easy to damage in the using process.

POSS is a cage type polysilsesquioxane with the general formula (RSiO)_3/2) n, wherein R is a group connected with a silicon atom on the top corner of the cube. The main properties of POSS materials depend on the R groups in their molecular structure, which can be reactive groups or inert groups. Turbo et al select a group R as-CH₂-CH₂-CF₃And the surface performance of the coating is researched by taking addition type silica gel as a main film forming substance. However, there is no concern about how to increase the hardness of the release layer and prevent the peeling in the field of tire molds, and the release property thereof is desired to be further improved. (reference: Tobo, Sizhakajie, Sihai, et al. Studies on Performance of addition Silicone base anti-adhesive coating [ J]Engineering and testing, 60(2):3.)

Therefore, the prior art has not provided a tire mold which has good anti-sticking performance, high hardness, difficult peeling and falling of the anti-sticking layer and long service life.

Disclosure of Invention

The invention aims to provide a tire mold with an inner surface anti-sticking coating, a preparation method and application thereof in tire preparation. The tire mold with the inner surface anti-sticking layer has the characteristics of high hardness, good anti-sticking capability, easiness in demolding, good wear resistance and long service life.

In one aspect, the present invention provides a high hardness anti-sticking tire mold comprising: the tire mold comprises a tire mold base body and an anti-sticking layer, wherein a rough contact surface is arranged between the tire mold base body and the anti-sticking layer.

The anti-sticking layer is made of materials with the mass ratio of 1: 0.1: (0.01-0.02): (0.01-0.02) bicomponent addition silica gel, submicron SiC, surfactant, octamethyl octasilsesquioxane.

Further, the surfactant is one or more of polyether F-6, methyldiethanolamine, polyether ester and polysiloxane; more preferably, the surfactant is polyether F-6.

In another aspect, the method for preparing a high hardness anti-sticking tire mold comprises:

firstly, carrying out sand blasting treatment on the inner surface of a tire mold matrix to obtain a rough surface;

and step two, mixing the two-component addition type silica gel, the submicron SiC, the surfactant and the octamethyl octasilsesquioxane to obtain anti-sticking slurry, spraying the anti-sticking slurry on the rough surface of the tire mold substrate to form a smooth and flat anti-sticking layer, curing for 6-10 hours at room temperature and with the relative humidity of 40% -80%, and thus obtaining the anti-sticking tire mold.

It is understood that the inner surface of the tire mold according to the present invention is a surface which is in contact with a rubber tire when the tire mold is used to manufacture a rubber tire.

Further, the sand blasting treatment is sand blasting by selecting sand grains with the grain diameter of 60-80 meshes; preferably, the particle size is 70 mesh.

The theory of mechanical interlocking is that the surface of any base material has a certain roughness, and the surface of the material has more or less defects such as holes, gaps, holes, cavities, grooves and the like. When the coating is sprayed on an irregular substrate, a composite zone which enables two substances to penetrate mutually is formed between the cured coating and the coated object. In the invention, the roughness of the surface of the tire mold matrix is increased in a sand blasting mode, so that the connection strength with the coating is increased.

Further, the material of the tire mold base body is one or more of 35 steel, 45 steel and A3 steel; preferably, the material of the tire mold base body is 35 steel.

Further, the thickness of the anti-sticking coating is 1-2 mm.

In another aspect, the use of the high hardness anti-sticking tire mold for making a tire.

Further, the tire comprises: all-steel radial tires and semi-steel radial tires.

Further, the tire is a semi-steel radial tire.

Still further, more preferably, the tire is a semisteel radial tire CH-268.

One preferred implementation is as follows:

s1, carrying out mold sand blasting:

the 35 steel tire mold base body is used as a test material for sand blasting, sand grains with the grain diameter of 70 meshes are selected for sand blasting, the compressed air pressure of a sand blasting machine is set to be 0.4MPa, the distance between a spray gun and the surface of the base body is 350mm, the sand blasting direction and the base body sample form 90 degrees, the sand blasting time is 4s until the surface is uniform, the sand blasting is completely carried out, the base body sample which is completely blasted is blown clean by oilless compressed air, and then the cleaning is carried out.

S2, preparation of the coating:

adding submicron SiC which is 10 percent of the mass of the two-component addition type silica gel, octamethyl octasilsesquioxane powder which is 2 percent of the total mass of the two-component addition type silica gel, and polyether F-6 which is 2 percent of the total mass of the two-component addition type silica gel into the two-component addition type silica gel, and stirring the mixture for 10min to uniformly mix the mixture to obtain the anti-sticking slurry.

S3 preparation of coating

And uniformly coating the obtained anti-sticking slurry on a rough inner surface formed by sandblasting a tire mold matrix, curing at the room temperature for 8 hours at the relative humidity of 60 percent, and obtaining the tire mold with the anti-sticking coating, namely the POSS mold for short, wherein the thickness of the coating is 2 mm.

The invention has the following beneficial effects:

1. according to the invention, octamethyl octasilsesquioxane and submicron SiC are added into the two-component addition type silica gel to prepare the novel anti-sticking coating for the tire mold, so that the friction force of the coating is reduced, and compared with the existing polytetrafluoroethylene coating, the anti-sticking coating has the advantages of excellent anti-sticking performance, increased hardness, wear resistance and prolonged service life.

2. The invention adopts the sand blasting process to treat the tire mold matrix, and particularly under the condition of 70-mesh sand treatment, the bonding strength of the coating and the tire mold matrix is high.

3. According to the invention, polyether F-6 is added into the coating, so that octamethyl octasilsesquioxane is uniformly distributed in the preparation process, bubbles are reduced, and the overall performance of the coating is improved.

4. The high-hardness anti-sticking tire mold has the characteristics of high demolding rate and long service life in the process of preparing a tire, particularly a semisteel radial tire CH-268.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

fig. 1 is a schematic structural view of a tire mold.

Detailed Description

The present application will now be described in detail with reference to specific embodiments and drawings for the purpose of illustrating the general concepts of the application more clearly.

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.

The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer.

In the following embodiments, reagents or instruments used are not indicated by manufacturers, and are all conventional products available by commercial purchase, unless otherwise specified.

Wherein: the MMU-10G end face friction abrasion testing machine is provided by Shandong European fibrate testing equipment, Inc.; octamethyl octasilsesquioxane is supplied by sigma aldrich trade ltd; polyether F-6 is provided by the Haian petrochemical plant of Jiangsu province; all-steel radial tires CH8207, all-steel radial tires 771CDL, all-steel radial tires 170CTL, semi-steel radial tires CH-268 and semi-steel radial tires CH-HP8806 are all provided by Yongfu tire Co., Ltd, Shandong; the LX-A Shore durometer is provided by Haibao instruments, Inc. of Wenzhou; the two-component addition type silica gel is provided by Hongye Jie technology Limited in Shenzhen city; SJ9080P sandblaster was supplied by syzhou scott mechanical equipment, inc.

In a first embodiment, as shown in fig. 1, the structure of the final tire mold comprises a tire mold base 1, and a release layer 2 is provided on the tire mold base 1.

Example 1

The embodiment provides a tire mold, which is prepared by adopting the following method:

s1, carrying out mold sand blasting:

carrying out sand blasting treatment on a 35 steel tire mold matrix 1 serving as a test material, selecting sand particles with the particle size of 60-80 meshes for sand blasting, setting the compressed air pressure of an SJ9080P sand blasting machine to be 0.4-0.5MPa, setting the distance between a spray gun and the surface of the matrix to be 300-350mm, setting the sand blasting direction to be 80-90 degrees with respect to the matrix sample, carrying out sand blasting for 3-5 seconds until the surface is uniform, completely blasting sand, blowing the completely blasted matrix sample clean by using oil-free compressed air, and then cleaning.

S2, preparation of the coating:

adding submicron SiC which is 10 percent of the mass of the two-component addition type silica gel, octamethyl octasilsesquioxane powder which is 1 to 2 percent of the total mass of the two-component addition type silica gel and polyether F-6 which is 1 to 2 percent of the total mass of the two-component addition type silica gel into the two-component addition type silica gel, and stirring the mixture for 10 to 30min to uniformly mix the mixture to obtain the anti-sticking slurry.

S3 preparation of coating

And uniformly coating the obtained anti-sticking slurry on the rough inner surface formed by sand blasting of the tire mold substrate 1, curing for 6-10 hours at room temperature with the relative humidity of 40% -80% and the thickness of the coating of 1-2mm to obtain the tire mold with the anti-sticking coating, namely the POSS mold for short.

Example 2

The tire mold was prepared in the same manner as in example 1 except that octamethyloctasilsesquioxane powder was added in an amount of 0.5% by mass.

Example 3

The tire mold was prepared in the same manner as in example 1 except that octamethyloctasilsesquioxane powder was added in an amount of 2.5% by mass.

Example 4

The tire mold was prepared in the same manner as in example 1 except that the thickness of the anti-sticking layer 2 was 3 mm.

Example 5

The tire mold was prepared as in example 1 except that the surfactant was methyldiethanolamine.

Example 6

The tire mold was prepared as in example 1 except that the surfactant was selected to be a polyether ester.

Example 7

The tire mold was prepared as in example 1 except that the surfactant was selected to be a polysiloxane.

Example 8

The tire mold was prepared as in example 1 except that the sand blasting was performed using a 90 mesh particle size.

Example 9

The preparation method of the tire mold is the same as that of the example 1, except that the material of the tire mold base body 1 is 45 steel.

Example 10

The preparation method of the tire mold is the same as that of the example 1, except that the material of the tire mold base 1 is A3 steel.

Comparative example 1

The tire mold was prepared by the same method as in example 1 except that the sand blast treatment was not performed and the anti-sticking layer 2 was not coated.

Comparative example 2

The tire mold was prepared by the same method as in example 1 except that the release layer 2 was applied without performing the sand blast treatment.

Comparative example 3

The tire mold was prepared by the same method as in example 1 except that the sand blasting was performed without applying the anti-sticking layer 2.

Comparative example 4

The tire mold was prepared as in example 1 except that no submicron SiC was added to the coating.

EXAMPLE 11 measurement of Friction coefficient

The magnitude of the friction coefficient directly determines the service life of the tire mold and the vulcanization quality of the rubber. The better the friction performance, the smaller the friction resistance in the rubber flowing process, so the smaller the abrasion, the better the vulcanization quality and the longer the service life of the mold.

The friction coefficient of the inner surface of the tire mold is measured by using an MMU-10G end face friction wear testing machine, in industrial production, the tire vulcanization temperature is generally controlled to be about 140 ℃, a cylindrical pin with the diameter of 30mm multiplied by 10mm prepared by vulcanized tire rubber is used as an upper friction pair, the inner surface of the tire mold is a lower friction pair, the loading force is 420N, the rotating speed is 30r/min, the friction time is 30min, and the temperature is 140 ℃.

TABLE 1 coefficient of friction for the examples

As can be seen from Table 1, the minimum friction coefficient of 0.3623 was achieved under the conditions of example 1. From examples 1-3, the coefficient of friction was influenced by the amount of octamethyloctasilsesquioxane powder added. It can be seen from examples 1 and 4 that the coefficient of friction is influenced by the thickness of the release layer 2, and that the coefficient of friction is increased when the thickness of the release layer 2 is 3mm, compared with the case where the thickness of the release layer 2 is 1 to 2 mm. It can be seen from example 1 and comparative examples 5 to 7 that the selection of different surfactants has an effect on the coefficient of friction, which is the smallest when polyether F-6 is selected as the surfactant. As can be seen from comparative examples 1 to 3, the friction coefficient is smaller in the case of applying the release layer 2.

Example 12 coating hardness determination

And performing hardness test by adopting an LX-A type Shore durometer, performing selection test at four different positions of the same sample, and averaging the results.

Table 2 hardness test results

As can be seen from table 2, the shore hardness of the coating was highest under the conditions of example 1 in examples 1 to 10, 57.54 HA. As can be seen from examples 1 and 9 to 10, the hardness of the coating layer influences the material quality of the tire mold base 1. And as can be seen from example 1 and comparative example 4, the submicron SiC layer affects the coating hardness and can play a role in improving the coating hardness.

Example 13 measurement of hydrophobicity of tire mold

On the basis of the above, the tire mold manufactured by the method described in example 1 was selected and the test was continued.

The quality of hydrophobicity is directly related to demoulding, anti-sticking and cleaning of a mould, the measurement index is the water contact angle, and an OCA15EC contact angle measuring instrument is adopted to measure the water contact angle of the coating. The water contact angles and surface energies of the polytetrafluoroethylene coating and the inventive POSS mold coating are shown in table 3. The coating of the invention has good hydrophobic property, and can meet the requirement of tire demoulding.

TABLE 3 Water contact Angle and surface energy measurements

Kind of coating	Water contact Angle θ/(°)	Surface energy/(mN. m-1)
			Polytetrafluoroethylene	106.5	15.15
POSS mold coating	110.2	13.99

Example 14 measurement of tire releasability

On the basis of the test result, the stripping performance and the using times of the tire are further tested. The semi-steel radial tire CH-268 was used as a test object, and the test results are shown in table 4.

TABLE 4 results of mold release test for various molds

Tyre model	Application temperature/. degree.C	Maximum number of uses	Mold release effect
				Example 1	150	607	Convenience of use
Example 8	150	420	Convenience of use
				Example 9	150	523	Convenience of use
Example 10	150	498	Convenience of use
				Comparative example 2	150	403	Obvious adhesion
Comparative example 4	150	328	Obvious adhesion

The tire mold has excellent non-stick property, can be easily taken down from the mold when the tire is demolded, saves time and improves production efficiency compared with the mold without a coating in the production process. Damage occurs when about 600 uses or so, and damage occurs when the prior art teflon coating is about 400 uses or so.

The grit blasting and addition of submicron SiC, as compared to example 1 and comparative examples 2 and 4, contribute to overall release coating stability and extend release coating life. From examples 1 and 8, it can be seen that the use of different grit blasting treatments has an effect on the service life of the tire mold. From example 1 and examples 9 to 10, it can be seen that the use of different steel materials as the material of the tire mold base 1 has an effect on the service life of the tire mold.

Example 15 measurement of suitability of tires of different types

On the basis of the above, the tire mold manufactured by the method described in example 1 was selected, and the suitability of the mold for demolding test was investigated for tires of different types, and the test results are shown in table 5.

TABLE 5 results of the tests for demolding of various tires

From the results in table 5, the maximum use times of the mold is affected by using different types of tires in the tire preparation process, wherein the service life of the semi-steel radial tire mold is longer than that of the all-steel radial tire mold, and the maximum use times of the semi-steel radial tire CH-268 mold is the maximum and can reach 596 times.

The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A high-hardness anti-sticking tire mold, comprising: the anti-sticking tire mold comprises a tire mold base body and an anti-sticking layer, wherein a rough contact surface is arranged between the tire mold base body and the anti-sticking layer;

2. The mold for the high-hardness anti-sticking tire according to claim 1, wherein the surfactant is one or more of polyether F-6, methyldiethanolamine, polyether ester, and polysiloxane; more preferably, the surfactant is polyether F-6.

3. The process for preparing a high-hardness anti-adhesion tyre mold as claimed in claim 1 or 2, characterized in that it comprises:

4. The method for preparing a high-hardness anti-sticking tire mold as claimed in claim 3, wherein the sand blasting treatment is sand blasting with sand particles having a particle size of 60 to 80 mesh; preferably, the particle size is 70 mesh.

5. The preparation method of the high-hardness anti-sticking tire mold as claimed in claim 3, wherein the material of the tire mold base is one or more of 35 steel, 45 steel and A3 steel; preferably, the material of the tire mold base body is 35 steel.

6. The method for preparing a high hardness anti-sticking tire mold as in claim 3, wherein the anti-sticking coating thickness is 1-2 mm.

7. Use of a high-hardness anti-sticking tyre mould as claimed in claim 1 or 2, in the manufacture of a tyre.

8. Use according to claim 7, wherein said tyre comprises: all-steel radial tires and semi-steel radial tires.

9. Use according to claim 8, wherein the tyre is a semi-steel radial tyre.

10. Use according to claim 9, wherein the tyre is a semi-steel radial tyre CH-268.