A second rubber layer composition of a cord layer, a cord layer and a vacuum tire

Abstract

The present invention belongs to the technical field of tire rubber materials and specifically discloses a carcass ply second rubber layer composition, a carcass ply and a vacuum tire. The carcass ply second rubber layer composition comprises, by mass, 90-95 parts of halogenated butyl rubber, 5-10 parts of BIMSM elastomer, 5-8 parts of polyamide resin, 4-5 parts of unsaturated polar plasticizer, 35-40 parts of carbon black, 15-20 parts of sheet reinforcing filler, 1-2 parts of borate coupling agent, 3-5 parts of phenolic resin, 1-2 parts of methylene donor, 4-5 parts of zinc oxide, 2-3 parts of stearic acid, 0.5-1 parts of sulfur, 0.7-1 parts of alkylphenol disulfide, and 1.5-2 parts of accelerator. The vacuum tire without inner rubber made from the cord layer produced has excellent air tightness, and its comprehensive performance is equivalent to that of the vacuum tire with inner rubber. The preparation and bonding process of the airtight layer rubber on the tire production line can be eliminated, which is beneficial to improving tire production efficiency and reducing product defective rate.

Description

Technical Field

[0001] The invention belongs to the technical field of tire rubber materials, and in particular relates to a cord layer and a second rubber material layer composition, a cord layer and a vacuum tire. Background Art

[0002] Vacuum tires, also known as tubeless tires, "low-pressure tires," or "pneumatic tires," do not use inner tubes. Air is directly filled into the inner cavity of the outer tire, eliminating friction between the inner and outer tires and allowing heat to dissipate directly from the wheel hub. Vacuum tires also have high elasticity and wear resistance, as well as good adhesion and heat dissipation properties. Using vacuum tires improves driving safety, allows continued driving even with small punctures, and is easier to repair mid-trip than with tube tires without removing the wheel hub. Because of their greater flexibility, they can improve the tire's cushioning performance and extend its service life. Consequently, vacuum tires are increasingly used on bicycles, motorcycles, cars, buses, and trucks.

[0003] To prevent compressed gas leakage and ensure airtightness, vacuum tires are usually covered with a layer of airtight inner layer rubber (inner rubber) on the inner surface of the tire with good sealing properties. Therefore, the airtight layer is one of the key components of vacuum tires. The airtight layer rubber of existing vacuum tires needs to go through processes such as mixing, extrusion, calendering, and vulcanization to be bonded to the inner surface of the tire. The bonding process is complex, the adhesion is weak, and delamination is prone to occur. Currently, some companies are using radiation cross-linking to improve the adhesion of the airtight layer and improve the delamination problem of the airtight layer. However, this method requires large-scale radiation equipment and adds radiation technology to the existing process. The process is more complicated and the cost is high, making it difficult to promote and apply.

[0004] Therefore, it is very necessary to develop a new vacuum tire and preparation method thereof. Summary of the Invention

[0005] The object of the present invention is to overcome the defects of the prior art and provide a carcass ply second rubber material layer composition, a carcass ply and a vacuum tire. The carcass ply second rubber material layer composition is prepared by using an appropriate amount of brominated isobutylene-paramethylstyrene copolymer (BIMSM elastomer) and halogenated butyl rubber, adding an adhesive system composed of an unsaturated polar plasticizer, a polyamide resin, a phenolic resin and a resin crosslinking agent, and a filling system composed of carbon black and a layer reinforcing filler. Finally, a vacuum tire without an inner rubber is prepared, which has excellent airtightness and comprehensive performance equivalent to that of a vacuum tire with an inner rubber. The preparation and lamination process of the airtight layer rubber on the tire production line can be eliminated, which is beneficial to improving tire production efficiency and reducing product defective rates.

[0006] In order to achieve the above objectives, one of the technical solutions of the present invention is: a second rubber layer composition of a cord layer, which comprises, by mass: 90-95 parts of halogenated butyl rubber, 5-10 parts of BIMSM elastomer, 5-8 parts of polyamide resin, 4-5 parts of unsaturated polar plasticizer, 35-40 parts of carbon black, 15-20 parts of sheet reinforcing filler, 1-2 parts of borate coupling agent, 3-5 parts of phenolic resin, 1-2 parts of methylene donor, 4-5 parts of zinc oxide, 2-3 parts of stearic acid, 0.5-1 part of sulfur, 0.7-1 part of alkylphenol disulfide, and 1.5-2 parts of accelerator.

[0007] In a preferred embodiment of the present invention, the halogenated butyl rubber is one or a combination of two or more of chlorinated butyl rubber and brominated butyl rubber.

[0008] In a preferred embodiment of the present invention, the unsaturated polar plasticizer is one of rosin nitrile resins, preferably gum rosin nitrile, with an acid value of 0.5-1.0 KOH / g and an appearance of a viscous oily liquid.

[0009] In a preferred embodiment of the present invention, the carbon black is one of N330, N339, and N375, or a combination of two or more thereof.

[0010] In a preferred embodiment of the present invention, the sheet-reinforcing filler is one or a combination of two or more of kaolin, mica powder, and multi-walled carbon nanotubes.

[0011] In a preferred embodiment of the present invention, the methylene donor is a mixture of hexamethoxymethylmelamine and a carrier, or a combination of two or more of hexamethylenetetramine.

[0012] In a preferred embodiment of the present invention, the phenolic resin is one or a combination of two or more of non-self-curing modified phenol formaldehyde resin and modified resorcinol formaldehyde resin.

[0013] In a preferred embodiment of the present invention, the sulfur and alkylphenol disulfide are used as vulcanizing agents. The sulfur is preferably insoluble sulfur, and the alkylphenol disulfide is preferably p-tert-butylphenol disulfide.

[0014] In a preferred embodiment of the present invention, the accelerator is a thiazole accelerator and a dithiocarbamate accelerator, the thiazole accelerator is 2,2'-dibenzothiazyl disulfide (accelerator DM), and the amount used is 1.2-1.5 parts by mass, and the dithiocarbamate accelerator is zinc pentamethylene dithiocarbamate (accelerator ZnPDC), and the amount used is 0.3-0.5 parts by mass.

[0015] In order to achieve the above objectives, the second technical solution of the present invention is: a method for preparing a second rubber layer composition of a cord ply, comprising the following steps:

[0016] (1) One-stage mixing: using an internal mixer, the conditions are: starting temperature 70-80°C, speed 45-50r / min, pressure 0.3-0.5MPa; the feeding sequence is: first action, add halogenated butyl rubber for 20-25s; second action, add 5 / 12-5 / 6 carbon black and mix for 20-25s; third action, add the remaining carbon black, sheet reinforcing filler, and coupling agent and mix for 20-25s; fourth action, clean and mix until 155-160°C and unload;

[0017] (2) Second stage mixing: using an internal mixer, the conditions are a starting temperature of 60-70°C, a rotation speed of 45-50 r / min, and a pressure of 0.3-0.5 MPa; in the first step, the above-mentioned first stage mixed rubber is added for 20-25 seconds; in the second step, the BIMSM elastomer, polyamide resin, unsaturated polar plasticizer, and 1 / 2 phenolic resin are added and mixed for 25-30 seconds; in the third step, the remaining phenolic resin and stearic acid are added and mixed for 15-20 seconds; in the fourth step, cleaning and mixing are carried out until the temperature reaches 145-150°C and unloading is performed;

[0018] (3) Final rubber mixing: using an internal mixer, the conditions are: starting temperature 40-50°C, speed 40-45 r / min, pressure 0.3-0.5 MPa; first action, add the above-mentioned two-stage rubber mix and mix for 20-25 seconds; second action, add vulcanizing agent, zinc oxide, accelerator, and methylene donor and mix for 20-25 seconds; third action, clean and mix until 100-105°C and unload;

[0019] (4) Preparation of target rubber composition: Using an open mill, set the front roller temperature to 60-65°C, the rear roller temperature to 70-75°C, the roller spacing to 1mm, and the rotation speed to 10r / min, the above-mentioned final rubber was tapped three times on the open mill, and the lower sheet was cooled to room temperature to obtain the target rubber composition.

[0020] In order to achieve the above objectives, the third technical solution of the present invention is: a cord layer comprising a cord layer second rubber layer composition.

[0021] In a preferred embodiment of the present invention, the cord layer comprises, from the outside to the inside, a first rubber layer composition, a nylon cord skeleton material and a second rubber layer composition.

[0022] In order to achieve the above purpose, the fourth technical solution of the present invention is: a method for preparing a cord layer, which is prepared by a calendering process, and the calendering process includes cord unwinding, joining, traction, front storage, traction, dust removal, guide, cloth expansion, gluing, cotton thread application, cooling, and winding.

[0023] In a preferred embodiment of the present invention, the calendering process is carried out using a four-roll calender. The temperature of the first roller of the four-roll calender is 85-90°C, the temperature of the second roller is 80-85°C, the temperature of the third roller is 90-95°C, and the temperature of the fourth roller is 95-100°C. The speed ratio of each roller is 1:1.3-1.5:1.3-1.5:1. The rubber material supplied between the first roller and the second roller is a conventional cord layer rubber material with a temperature of 70- 80°C, the thickness of the rubber coating on the second roller is 5-6mm, the rubber supplied to the third roller and the fourth roller is the second rubber layer composition of the cord layer of the present invention, the glue temperature is 80-85°C, and the thickness of the rubber coating on the third roller is 0.7-0.8mm; the temperature of the nylon cord before gluing in the calendering process is 50-55°C, and the calendering speed is 45-50m / min; the thickness of the second rubber layer of the cord layer after gluing in the calendering process is 0.7-0.8mm.

[0024] In order to achieve the above objectives, the fifth technical solution of the present invention is: a vacuum tire including the above-mentioned cord layer.

[0025] In a preferred embodiment of the present invention, the vacuum tire comprises a tread portion, a buffer layer and a cord layer from the outside to the inside.

[0026] In a preferred embodiment of the present invention, the vacuum tire has 1 to 4 cord layers.

[0027] In a preferred embodiment of the present invention, the vacuum tire is further provided with sidewalls and wire rings.

[0028] In order to achieve the above objectives, the sixth technical solution of the present invention is: a method for preparing a vacuum tire, comprising the following steps:

[0029] (1) The cord layers are sequentially attached to the forming drum of the forming machine so that the second rubber layer composition of the cord layers is located at the innermost layer of the green tire when the green tire is assembled, and then the buffer layer is attached, and then the bead ring is positioned and the airbag is rolled up, and finally the tread rubber and sidewall rubber are attached to complete the green tire molding;

[0030] (2) vulcanizing the green tire formed in step (1) to obtain a finished tire.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention uses a cord layer to replace the tire innerliner rubber while ensuring the tire's airtightness, which is beneficial to improving tire production efficiency and reducing product defect rates;

[0033] 2. The raw rubber system of the present invention uses a combination of BIMSM elastomer and halogenated butyl rubber. The BIMSM elastomer is a fully saturated terpolymer with an isobutylene backbone and p-methyl (PMS) and brominated p-methyl (Br-PMS) side chains. Halogenated butyl rubber is obtained by adding chlorine or bromine to butyl rubber. Both have excellent air tightness, aging resistance, and weather resistance, but have disadvantages such as poor adhesion and low adhesion strength, poor adhesion to the carcass material, and the risk of delamination. There is no precedent for their use in carcass rubber compositions. By adding an adhesive system consisting of an unsaturated polar plasticizer, a polyamide resin, a phenolic resin, and a methylene donor to the second rubber layer of the carcass, wherein the BIMSM elastomer, the polyamide resin, and the unsaturated polar plasticizer constitute a first tackifying component, the benzyl bromide in the BIMSM elastomer is less affected by macromolecular chain steric hindrance, has strong reactivity, and readily undergoes a cross-linking reaction with the terminal amino groups on the polyamide resin. The unsaturated polar plasticizer has good compatibility with the polyamide resin. On the other hand, it can reduce the surface tension of the BIMSM elastomer and the nylon cord skeleton material dipping latex, promote the cross-linking reaction between the BIMSM and the polyamide resin, and at the same time enhance the physical adhesion between the polyamide resin and the nylon cord dipping component and the nylon cord fiber, such as the intermolecular attraction and hydrogen bonding force, so that the polyamide resin forms a bridge for better adhesion between the rubber component of the tire cord layer and the nylon cord skeleton material. The phenolic resin, the methylene donor, and the unsaturated polar plasticizer constitute the second tackifying component. The unsaturated polar plasticizer has good compatibility with the phenolic resin, which facilitates the reaction between the phenolic resin and the methylene donor to form a resin network for improving adhesion. The unsaturated polar plasticizer synergistically enhances the adhesion and adhesion strength between the second rubber layer of the tire cord layer and the cord yarn skeleton material, thus breaking the application limitation of butyl rubber in the tire cord layer due to its poor adhesion performance.

[0034] 3. The present invention optimizes the ratio of carbon black to lamellar reinforcing filler, and through coupling agent modification and optimized mixing process, the lamellar filler with a large aspect ratio and high orientation is dispersed and arranged in an orderly manner with the carbon black in the rubber matrix of the carcass ply. This fully utilizes the filler's reinforcing properties while significantly improving the gas barrier properties of the carcass ply rubber compound.

[0035] 4. The present invention optimizes the thickness of the second rubber layer of the tire cord ply, resolving issues such as wrinkles, separation of the cord from the rubber, and air leakage caused by the cord puncturing the rubber due to a smaller thickness, and uneven cord arrangement and heavier tires due to a larger thickness. This improves the calendering workability of this rubber layer and helps achieve better airtightness in the tire.

[0036] 5. The vulcanization system of the present invention combines a semi-effective sulfur vulcanization system with a metal oxide vulcanization system, with insoluble sulfur and alkylphenol disulfide as the first vulcanizing agent, zinc oxide as the second vulcanizing agent, thiazole accelerators and dithiocarbamate accelerators as accelerators, and some zinc oxide and stearic acid as activators. The synergistic effect of these components can effectively increase the crosslinking rate of butyl rubber, improve the physical strength of the ply rubber material, and improve the bonding strength between the ply rubber material and the ply skeleton material.

[0037] 6. The present invention uses a four-roll calender to achieve a one-time continuous double-sided gluing process for the tire cord layer. By controlling parameters such as the calender roller temperature, the calender roller speed ratio, and the thickness of the roller rubber coating, the calendered tire cord layer rubber has the advantages of uniform thickness, smooth surface, and non-wrinkle, which is beneficial to improving the adhesion and airtightness between the tire cord layer rubber and the tire cord skeleton material. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is described in more detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to these embodiments.

[0039] Example 1

[0040] A second rubber layer composition of a cord ply, the composition ratio of which is shown in Table 1, is prepared by the following method:

[0041] Stage 1 mixing: Use an internal mixer with an initial temperature of 80°C, a speed of 50 r / min, and a pressure of 0.5 MPa. The feeding sequence is as follows: First, add bromobutyl rubber for 25 seconds; second, add 2 / 3 of the carbon black and mix for 25 seconds; third, add the remaining carbon black, kaolin, and coupling agent and mix for 25 seconds; fourth, clean and mix until 160°C before unloading.

[0042] Second stage mixing: Use an internal mixer with the following conditions: starting temperature 70°C, speed 50r / min, and pressure 0.5MPa. First, add the first stage mix for 25 seconds. Second, add the BIMSM elastomer, polyamide resin, unsaturated polar plasticizer, and 1 / 2 phenolic resin and mix for 30 seconds. Third, add the remaining phenolic resin and stearic acid and mix for 20 seconds. Fourth, clean and mix until 145°C before unloading.

[0043] Final rubber mixing: Use an internal mixer at a starting temperature of 40°C, a speed of 40 r / min, and a pressure of 0.3 MPa. First, add the above-mentioned second-stage rubber mix and mix for 25 seconds. Second, add the vulcanizing agent, zinc oxide, accelerator, and methylene donor and mix for 25 seconds. Third, clean and mix until 100°C before unloading.

[0044] An open mill was used with the front roller temperature set at 60°C, the rear roller temperature set at 70°C, the roller spacing set at 1 mm, and the rotation speed set at 10 r / min. The final rubber mixture was tapped three times on the left and right sides of the open mill, and the lower sheet was cooled to room temperature to obtain the target rubber composition.

[0045] Example 2

[0046] A second rubber layer composition of a cord ply, the composition ratio of which is shown in Table 1, is prepared according to the preparation method of Example 1.

[0047] Example 3

[0048] A second rubber layer composition of a cord ply, the composition ratio of which is shown in Table 1, is prepared according to the preparation method of Example 1.

[0049] Example 4

[0050] A second rubber layer composition of a cord ply, the composition ratio of which is shown in Table 1, is prepared according to the preparation method of Example 1.

[0051] Example 5

[0052] A tire cord ply comprising the cord ply second rubber layer composition of Example 1 is prepared by the following method:

[0053] A tire cord ply was prepared by calendering a nylon 66 cord with a specification of 840D / 2, a density of 28 strands / inch, and a thickness of 0.55 mm using the above-mentioned cord ply and second rubber compound layer composition. The calendering process was briefly as follows: cord unwinding → joining → traction → front storage → traction → dust removal → guiding → spreading → gluing → cotton thread application → cooling → winding; a four-roll calender was used for the calendering operation. The rollers of the four-roll calender were numbered No. 1#, No. 2#, No. 3#, and No. 4# from top to bottom. The temperature of No. 1# roller was 90°C, the temperature of No. 2# roller was 85°C, and the temperature of No. The temperature of No. 3 roller is 95°C, the temperature of No. 4 roller is 100°C, the roller speed ratio is 1:1.4:1.4:1, the rubber material supplied between No. 1# roller and No. 2# roller is a conventional cord layer rubber material, the rubber temperature is 80°C, the rubber thickness of No. 2# roller is 5mm, the rubber material supplied to No. 3# roller and No. 4# roller is the second rubber layer composition of the cord layer of the present invention, the rubber temperature is 85°C, and the rubber thickness of No. 3# roller is 0.7mm; the temperature of the nylon cord before gluing in the gluing process is 55°C, and the calendering speed is 50m / min; the thickness of the second rubber layer of the cord layer after gluing in the gluing process is 0.7mm.

[0054] Example 6

[0055] A tire cord ply comprising the cord ply second rubber layer composition of Example 2 is prepared by the following method:

[0056] A tire cord ply was prepared by calendering a nylon 66 cord with a specification of 840D / 2, a density of 28 strands / inch, and a thickness of 0.55 mm using the above-mentioned cord ply and second rubber compound layer composition. The calendering process was briefly as follows: cord unwinding → joining → traction → front storage → traction → dust removal → guiding → spreading → gluing → cotton thread application → cooling → winding; a four-roll calender was used for the calendering operation. The rollers of the four-roll calender were numbered No. 1#, No. 2#, No. 3#, and No. 4# from top to bottom. The temperature of No. 1# roller was 90°C, the temperature of No. 2# roller was 85°C, and the temperature of No. The temperature of No. 3 roller is 95°C, the temperature of No. 4 roller is 100°C, the roller speed ratio is 1:1.4:1.4:1, the rubber material supplied between No. 1# roller and No. 2# roller is a conventional cord layer rubber material, the rubber temperature is 80°C, the rubber coating thickness of No. 2# roller is 5mm, the rubber material supplied to No. 3# roller and No. 4# roller is the second rubber layer composition of the cord layer of the present invention, the rubber temperature is 85°C, the rubber coating thickness of No. 3# roller is 0.8mm; the temperature of the nylon cord before gluing in the gluing process is 55°C, and the calendering speed is 50m / min; the thickness of the second rubber layer of the cord layer after gluing in the gluing process is 0.8mm.

[0057] Example 7

[0058] A tire cord ply comprising the cord ply second rubber material layer composition of Example 3 was prepared according to the method of Example 5.

[0059] Example 8

[0060] A tire cord ply comprising the cord ply second rubber material layer composition of Example 4 was prepared according to the method of Example 6.

[0061] Example 9

[0062] A vacuum tire comprising the cord layer of Example 5 is prepared by the following method:

[0063] (1) The cord layer is attached to the forming wheel of the forming machine so that the second rubber layer composition of the cord layer is located at the innermost layer of the green tire when the green tire is assembled. The buffer layer is then attached, and the wire ring is positioned and the airbag is rolled up. Finally, the tread rubber and sidewall rubber are attached to complete the forming of the green tire.

[0064] (2) vulcanizing the green tire formed in step (1) to obtain a finished tire.

[0065] Example 10

[0066] A vacuum tire including the cord layer of Example 6 is prepared according to the method of Example 9.

[0067] Example 11

[0068] A vacuum tire including the cord layer of Example 7 is prepared according to the method of Example 9.

[0069] Example 12

[0070] A vacuum tire including the cord layer of Example 8 is prepared according to the method of Example 9.

[0071] Comparative Example 1

[0072] A second rubber layer composition of a cord ply is a conventional cord rubber formulation, the composition ratio of which is shown in Table 1, and is prepared by the following method:

[0073] Stage 1 mixing: Use an internal mixer with an initial temperature of 80°C, a speed of 50 r / min, and a pressure of 0.5 MPa. The feeding sequence is as follows: First, add natural rubber and butadiene rubber for 25 seconds; Second, add 2 / 3 of the carbon black and mix for 25 seconds; Third, add the remaining carbon black and mix for 25 seconds; Fourth, clean and mix until the temperature reaches 160°C before unloading.

[0074] Second stage mixing: Use an internal mixer with the following conditions: starting temperature 70°C, speed 50r / min, and pressure 0.5MPa. First, add the first stage mix for 25 seconds; second, add 1 / 2 of the phenolic resin and mix for 30 seconds; third, add the remaining phenolic resin and stearic acid and mix for 20 seconds; fourth, clean and mix until 145°C before unloading.

[0075] Final rubber mixing: Use an internal mixer with the following conditions: starting temperature 40°C, speed 40r / min, and pressure 0.3MPa. First, add the above-mentioned second-stage rubber mix and mix for 25 seconds; second, add the vulcanizing agent, zinc oxide, accelerator, and methylene donor and mix for 25 seconds; third, clean and mix until 100°C and unload;

[0076] An open mill was used with the front roller temperature set at 60°C, the rear roller temperature set at 70°C, the roller spacing set at 1 mm, and the rotation speed set at 10 r / min. The final rubber mixture was tapped three times on the left and right sides of the open mill, and the lower sheet was cooled to room temperature to obtain the target rubber composition.

[0077] Comparative Example 2

[0078] A second rubber layer composition of a cord ply is a conventional cord rubber formula, and its composition ratio is shown in Table 1. It is prepared according to the preparation method of Comparative Example 1.

[0079] Comparative Example 3

[0080] A second rubber layer composition of a cord ply is a conventional airtight layer formulation, and its composition ratio is shown in Table 1. It is prepared by the following method:

[0081] Primary mixing: Use an internal mixer with an initial temperature of 80°C, a speed of 50 r / min, and a pressure of 0.5 MPa. The feeding sequence is as follows: First, add bromobutyl rubber for 25 seconds; second, add 2 / 3 of the carbon black and mix for 25 seconds; third, add the remaining carbon black, kaolin, and coupling agent and mix for 25 seconds; fourth, clean and mix until 160°C before unloading.

[0082] Second stage mixing: Use an internal mixer with the following conditions: starting temperature 70°C, speed 50r / min, and pressure 0.5MPa. First, add the first stage mix for 25 seconds. Second, add the BIMSM elastomer and 1 / 2 phenolic resin and mix for 30 seconds. Third, add the remaining phenolic resin and stearic acid and mix for 20 seconds. Fourth, clean and mix until 145°C before unloading.

[0083] Final rubber mixing: Use an internal mixer with the following conditions: starting temperature 40°C, speed 40r / min, and pressure 0.3MPa. First, add the above-mentioned second-stage rubber mix and mix for 25 seconds; second, add the vulcanizing agent, zinc oxide, accelerator, and methylene donor and mix for 25 seconds; third, clean and mix until 100°C and unload;

[0084] An open mill was used with the front roller temperature set at 60°C, the rear roller temperature set at 70°C, the roller spacing set at 1 mm, and the rotation speed set at 10 r / min. The final rubber mixture was tapped three times on the left and right sides of the open mill, and the lower sheet was cooled to room temperature to obtain the target rubber composition.

[0085] Comparative Example 4

[0086] A tire cord ply comprising the cord ply second rubber material layer composition of Comparative Example 1 is prepared as follows:

[0087] A tire cord ply was prepared by calendering a nylon 66 cord with a specification of 840D / 2, a density of 28 strands / inch, and a thickness of 0.55 mm using the above-mentioned cord ply and second rubber compound layer composition. The calendering process was briefly as follows: cord unwinding → joining → traction → front storage → traction → dust removal → guiding → spreading → gluing → cotton thread application → cooling → winding; a four-roll calender was used for the calendering operation. The rollers of the four-roll calender were numbered No. 1#, No. 2#, No. 3#, and No. 4# from top to bottom. The temperature of No. 1# roller was 90°C, the temperature of No. 2# roller was 85°C, and the temperature of No. The temperature of No. 3 roller is 95°C, the temperature of No. 4 roller is 100°C, the roller speed ratio is 1:1.4:1.4:1, the rubber material supplied between No. 1# roller and No. 2# roller is a conventional cord layer rubber material, the rubber temperature is 80°C, the rubber thickness of No. 2# roller is 5mm, the rubber material supplied to No. 3# roller and No. 4# roller is the second rubber layer composition of the cord layer of the present invention, the rubber temperature is 85°C, the rubber thickness of No. 3# roller is 0.3mm; the temperature of the nylon cord before gluing in the gluing process is 55°C, and the calendering speed is 50m / min; the thickness of the second rubber layer of the cord layer after gluing in the gluing process is 0.3mm.

[0088] Comparative Example 5

[0089] A tire cord ply comprising the cord ply second rubber layer composition of Comparative Example 2 is prepared in the same manner as in Example 6.

[0090] Comparative Example 6

[0091] A tire cord ply comprising the cord ply second rubber layer composition of Comparative Example 3 is prepared in the same manner as in Example 6.

[0092] Comparative Example 7

[0093] A vacuum tire including the cord layer in Comparative Example 4 was prepared by the following method:

[0094] (1) The inner rubber, the cord layer, and the buffer layer are attached to the forming wheel of the forming machine in sequence. The wire ring is then positioned to roll up the airbag. Finally, the tread rubber and the sidewall rubber are attached to complete the forming of the green tire.

[0095] (2) vulcanizing the green tire formed in step (1) to obtain a finished tire.

[0096] Comparative Example 8

[0097] A vacuum tire including the cord layer in Comparative Example 5 was prepared according to the method of Example 9.

[0098] Comparative Example 9

[0099] A vacuum tire including the cord layer in Comparative Example 6 was prepared according to the method of Example 9.

[0100] The rubber mixes of the second rubber material layer compositions of the tire carcass prepared in Examples 1-4 and Comparative Examples 1-3 were placed in a predetermined mold and vulcanized at 160°C for 18 minutes to produce vulcanized semi-finished products. The adhesion and airtightness properties of the vulcanized semi-finished products were tested. The test results are shown in Table 2. The adhesion, airtightness, high-speed, and durability properties of the finished tires prepared in Examples 9-12 and Comparative Examples 7-9 were tested. The test results are shown in Table 3.

[0101] The performance test method is as follows:

[0102] (1) Adhesion performance: According to GB / T40725-2021 standard, the peeling strength between a single dipped cord and rubber is measured using a tensile testing machine. The results are expressed as relative values. The larger the value, the better the adhesion performance.

[0103] (2) Airtightness: The airtightness of semi-finished products is measured by a gas permeometer. The results are expressed as relative values. A larger value indicates less gas permeation and better airtightness. The airtightness of finished tires is measured by testing the air leakage rate of tires after 30 days of standing. The results are expressed as relative values. A larger value indicates less gas permeation and better airtightness.

[0104] (3) High-speed performance: observe the damage of the tire after testing at 145 km / h for 30 minutes;

[0105] (4) Durability: Observe the damage of the tire after testing at 81 km / h for 38 hours.

[0106] Table 1. Composition ratios of Examples 1-4 and Comparative Examples 1-3 by mass (mass / part)

[0107]

[0108] Table 2. Comparative results of the properties of the semi-finished products of the second rubber layer composition of the cord ply prepared in Examples 1-4 and Comparative Examples 1-3

[0109]

[0110] Table 3. Comparative results of the performance of the finished tires obtained in Examples 9-12 and Comparative Examples 7-9

[0111]

[0112] From the comparison of the performance results of the finished tires prepared in Comparative Examples 7 and 8, it can be seen that by eliminating the use of the airtight layer, without changing the formula of the second rubber layer of the carcass ply, and only increasing the thickness of the second rubber layer of the carcass ply to 0.8 mm, the airtightness performance of the tire is significantly reduced, and the high-speed and durability performance of the tire are poor, making it unusable.

[0113] Comparing the performance results of the semi-finished products prepared in Comparative Examples 3 and 2, and the finished tires prepared in Comparative Examples 9 and 8, the raw rubber system in the formulation replaced natural rubber and butadiene rubber with bromobutyl rubber and BIMSM, the filler system replaced part of the carbon black with kaolin, and the accelerator ZnPDC replaced part of the accelerator DM. Although the airtightness of the semi-finished products and tires was significantly improved when they were left standing, the adhesion performance of the semi-finished products was significantly reduced, and the high-speed and durability performance of the tires were poor, making them unusable.

[0114] Comparing the performance of the semi-finished products prepared in Examples 1-4 with that in Comparative Example 3, the first tackifying component composed of unsaturated rosin nitrile plasticizer, polyamide resin, and BIMSM is added to the formula of the second rubber layer of the carcass ply, which synergizes with the second tackifying component composed of phenolic resin and methylene donor, and effectively complements and strengthens the adhesion and adhesion strength of the rubber of the second rubber layer of the carcass ply and the carcass skeleton material in the tire. The adhesion performance of the semi-finished products is significantly improved, and the air tightness is also improved. Comparing the performance results of the finished tires prepared in Examples 9-12 with those in Comparative Example 9, the air tightness, high speed and durability of the tires of the examples are significantly improved, and the overall performance is equivalent to that of the current tire in Comparative Example 7, meeting the performance requirements of the tire.

[0115] Compared with the performance of the semi-finished products obtained in Example 1 and Example 3, as the amount of BIMSM and polyolefin resin increases, the adhesive performance and airtightness of the rubber compound tend to increase slightly. However, excessive amounts of both will cause excessive viscosity of the rubber compound during subsequent calendering, affecting the calendering operability. Therefore, under the premise of ensuring calendering operability and cost considerations, the amount of BIMSM should not exceed 10 parts and the polyamide resin should not exceed 8 parts. If the amount of BIMSM is less than 5 parts and the amount of polyamide resin is less than 5 parts, the adhesive performance is poor. Therefore, using 5-10 parts of BIMSM and 5-8 parts of polyamide resin can maximize the excellent adhesive performance and airtightness while ensuring the calendering operability.

[0116] Comparing the performance results of the finished tires obtained in Example 9 and Example 10, and in Example 11 and Example 12, the formula of the second rubber layer of the cord ply is consistent, and the thickness increases, and the airtightness performance of the tire is slightly improved. However, if the thickness of the second rubber layer of the cord ply is further increased, problems such as uneven cord arrangement and heavy tire will occur. If the thickness of the cord ply is too small, wrinkles, separation of the cord and the rubber, and air leakage due to the cord puncturing the rubber will easily occur. Therefore, the thickness of the second rubber layer of the cord ply is controlled to 0.7-0.8 mm, and the tire can obtain better airtightness to the maximum extent.

[0117] By adjusting the composition components of the second rubber layer of the above-mentioned cord layer, and combining the adjustment of the cord rubber layer thickness and the cord gluing process parameters, the prepared vacuum tire without inner rubber has excellent airtightness, and its comprehensive performance is equivalent to that of a vacuum tire with inner rubber. The preparation and bonding process of the airtight layer rubber on the tire production line can be eliminated, which is beneficial to improving tire production efficiency and reducing product defective rate.

[0118] The above embodiments and descriptions are only for explaining the principles of the present invention and are not intended to limit the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A second rubber layer composition for a cord ply, characterized in that: The invention comprises, by mass, 90-95 parts of halogenated butyl rubber, 5-10 parts of BIMSM elastomer, 5-8 parts of polyamide resin, 4-5 parts of unsaturated polar plasticizer, 35-40 parts of carbon black, 15-20 parts of sheet reinforcing filler, 1-2 parts of borate coupling agent, 3-5 parts of phenolic resin, 1-2 parts of methylene donor, 4-5 parts of zinc oxide, 2-3 parts of stearic acid, 0.5-1 part of sulfur, 0.7-1 part of alkylphenol disulfide, and 1.5-2 parts of accelerator; the unsaturated polar plasticizer is one of rosin nitrile resins; and the cord layer comprises, from the outside to the inside, a first rubber layer composition, a nylon cord skeleton material, and a second rubber layer composition.

2. The second rubber layer composition of the carcass ply according to claim 1, wherein: The accelerator is a combination of a thiazole accelerator and a dithiocarbamate accelerator. The thiazole accelerator is 2,2'-dibenzothiazole disulfide, and the amount used is 1.2-1.5 parts by mass. The dithiocarbamate accelerator is zinc pentamethylene dithiocarbamate, and the amount used is 0.3-0.5 parts by mass.

3. A carcass ply comprising the carcass ply second rubber layer composition according to claim 1 or 2.

4. The cord layer according to claim 3, wherein: The cord layer comprises, from the outside to the inside, a first rubber layer composition, a nylon cord skeleton material and a second rubber layer composition.

5. A vacuum tire comprising the cord layer according to claim 3.

6. The vacuum tire according to claim 5, characterized in that The vacuum tire comprises a tread portion, a buffer layer and a cord layer in sequence from the outside to the inside.

7. A method for preparing the second rubber layer composition of a carcass ply according to claim 1 or 2, characterized in that: The following steps are involved: (1) One-stage mixing: using an internal mixer, the conditions are: starting temperature 70-80°C, speed 45-50r / min, pressure 0.3-0.5MPa; the feeding sequence is: first action, add halogenated butyl rubber for 20-25s; second action, add 5 / 12-5 / 6 carbon black and mix for 20-25s; third action, add the remaining carbon black, sheet reinforcing filler, and coupling agent and mix for 20-25s; fourth action, clean and mix until 155-160°C and unload; (2) Second stage mixing: using an internal mixer, the conditions are a starting temperature of 60-70°C, a rotation speed of 45-50 r / min, and a pressure of 0.3-0.5 MPa; in the first step, the above-mentioned first stage mixed rubber is added for 20-25 seconds; in the second step, the BIMSM elastomer, polyamide resin, unsaturated polar plasticizer, and 1 / 2 phenolic resin are added and mixed for 25-30 seconds; in the third step, the remaining phenolic resin and stearic acid are added and mixed for 15-20 seconds; in the fourth step, cleaning and mixing are carried out until the temperature reaches 145-150°C and unloading is performed; (3) Final rubber mixing: using an internal mixer, the conditions are: starting temperature 40-50°C, speed 40-45 r / min, pressure 0.3-0.5 MPa; first action, add the above-mentioned two-stage rubber mix and mix for 20-25 seconds; second action, add vulcanizing agent, zinc oxide, accelerator, and methylene donor and mix for 20-25 seconds; third action, clean and mix until 100-105°C and unload; (4) Preparation of target rubber composition: Using an open mill, set the front roller temperature to 60-65°C, the rear roller temperature to 70-75°C, the roller spacing to 1mm, and the rotation speed to 10r / min, the above-mentioned final rubber was tapped three times on the open mill, and the lower sheet was cooled to room temperature to obtain the target rubber composition.

8. A method for preparing a cord layer according to claim 4, characterized in that: The calendering process is prepared by a four-roll calender for gluing. The temperature of the first roller of the four-roll calender from top to bottom is 85-90°C, the temperature of the second roller is 80-85°C, the temperature of the third roller is 90-95°C, and the temperature of the fourth roller is 95-100°C. The speed ratio of each roller is 1:1.3-1.5:1.3-1.5:

1. The glue supplied between the first roller and the second roller is the first glue layer composition, and the glue temperature is 7 0-80℃, the thickness of the rubber coating on the second roller is 5-6mm, the rubber supplied by the third roller and the fourth roller is a composition of the second rubber layer of the cord layer, the glue temperature is 80-85℃, and the thickness of the rubber coating on the third roller is 0.7-0.8mm; the temperature of the nylon cord before gluing in the calendering process is 50-55℃, and the calendering speed is 45-50m / min; the thickness of the second rubber layer of the cord layer after gluing in the calendering process is 0.7-0.8mm.

9. A method for preparing a vacuum tire according to claim 5 or 6, characterized in that: The following steps are involved: (1) The cord layers are sequentially attached to the forming drum of the forming machine so that the second rubber layer composition of the cord layers is located at the innermost layer of the green tire when the green tire is assembled, and then the buffer layer is attached, and then the bead ring is positioned and the airbag is rolled up, and finally the tread rubber and sidewall rubber are attached to complete the green tire molding; (2) vulcanizing the green tire formed in step (1) to obtain a finished tire.

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