Self-repairing rubber composition as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of tires, and particularly relates to a self-repairing rubber composition as well as a preparation method and application thereof. The invention provides a self-repairing rubber composition, which is prepared from the following ingredients in parts by weight: 30 to 60 parts of natural rubber, 30 to 60 parts of butyl rubber and / or halogenated butyl rubber, 10 to 30 parts of liquid isoprene rubber, 20 to 80 parts of liquid polyisobutene rubber, 5 to 15 parts of carbon black, 10 to 40 parts of softening agents, 1 to 10 parts of light calcium carbonate and 5 to 10 parts of tackifying resin. 1-5 parts of a hydrogenated styrene-isoprene block copolymer, 1-8 parts of an active agent, 0-10 parts of an antioxidant and 1-10 parts of a vulcanizing agent. The liquid isoprene rubber and the liquid polyisobutene are added, so that the composition has good self-repairing performance and softness; meanwhile, the tackifying resin and the hydrogenated styrene-isoprene block copolymer are used, so that the composition has better tensile strength and cohesive force.

Description

Technical Field

[0001] The invention belongs to the technical field of tires, and in particular relates to a self-repairing rubber composition and a preparation method and application thereof. Background Art

[0002] As one of the important parts of a vehicle, the pneumatic tire (hereinafter referred to as the tire) is in direct contact with the ground and plays an important role in support, traction, braking, shock absorption, etc. The safety of the tire is of vital importance to the drivers and passengers on the vehicle. For electric scooters, the problem of tire failure caused by foreign objects puncturing the tire is becoming more and more prominent.

[0003] In recent years, in order to solve the problem of tire blowouts caused by nails, major tire manufacturers have actually used self-repairing tires with a puncture sealing layer pre-installed on the inside of the tire tread in vehicles.

[0004] As a tire with puncture-proof function, a sealing material is coated on the inner surface of the tire. When the tire is punctured by foreign objects during driving, the holes formed will be automatically sealed by the sealing material. Technicians have conducted various studies on sealing materials, but the cost and performance have limitations, and the sealing materials used for automobile tires are not completely suitable for electric scooter tires with small wheel diameters.

[0005] CN 103102866 A discloses an adhesive tire anti-puncture, explosion-proof and leak-proof smart glue, including the following components and weight parts: 20-25 rubber, 15-20 carbon black, 1-2 zinc oxide, 30-50 asphalt, 1-2 accelerators, 5-8 binders; rubber, carbon black, zinc oxide, asphalt, and accelerators are placed in a reactor, heated to 110-180°C, stirred for 1 hour, and then the binder is added and stirred for 10 minutes, which is a high molecular intelligent active polymer glue; the adhesive anti-puncture, explosion-proof and leak-proof smart glue is composed of an anti-adhesive isolation paper film and a high molecular intelligent active polymer glue, which always remains soft and never solidifies after use, has strong adhesion, good flexibility, special ductility, and has intelligent self-healing function. However, the material takes too long to repair the wound, resulting in a lot of gas loss in the tire when the leak-proof patching material is repairing the leak, affecting the vehicle's continued driving.

[0006] Therefore, it is very important to develop a puncture-proof sealing material that has both cost and performance and can be used on small-diameter tires. Summary of the invention

[0007] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the embodiment of the present invention provides a self-repairing rubber composition, which has good self-repairing performance and softness; at the same time, it has good tensile strength and cohesion. The rubber composition can quickly repair the holes formed by punctures in tires without affecting the driving of vehicles.

[0008] The self-repairing rubber composition of the embodiment of the present invention comprises the following components in parts by weight:

[0009] 30-60 parts of natural rubber, 30-60 parts of butyl rubber and / or halogenated butyl rubber, 10-30 parts of liquid isoprene rubber, 20-80 parts of liquid polyisobutylene rubber, 5-15 parts of carbon black, 10-40 parts of softener, 1-10 parts of light calcium carbonate, 5-10 parts of tackifying resin, 1-5 parts of hydrogenated styrene-isoprene block copolymer, 1-8 parts of activator, 0-10 parts of antioxidant and 1-10 parts of vulcanizing agent.

[0010] The advantages and technical effects brought by the self-repairing rubber composition of the embodiment of the present invention are as follows: 1. In the embodiment of the present invention, by using a composition of natural rubber and butyl rubber, the bubbles generated during the spraying process can be improved, and the production quality of the product can be improved; 2. In the embodiment of the present invention, by adding low molecular weight liquid isoprene rubber and liquid polyisobutylene with good viscosity and self-repairing properties, the strength of the components can be reduced, so that the rubber composition has good self-repairing properties and softness, and has a good coating effect on pierced foreign objects, and will not separate from the inner wall of the tire and lose its self-repairing properties during continuous use of the tire; 3. In the embodiment of the present invention, by adding tackifying resin and hydrogenated styrene- Isoprene block copolymer, hydrogenated styrene-isoprene block copolymer has a shorter methyl unit series and will not crystallize, so it has good softness and elasticity, and the softness is further enhanced when it is used with softening oil, and it shows good tensile strength and cohesion in the composition. The tackifying resin has a higher melting point. When the ambient temperature rises and the strength of the small molecular weight component in the rubber composition decreases, the tackifying resin can still enable the rubber composition to maintain good strength and viscosity, so that the composition still has good self-repairing performance under high temperature conditions; 4. In the embodiment of the present invention, when the rubber composition is used in a tire, it can be quickly repaired after the tire is punctured, and the vehicle continues to drive without affecting it.

[0011] In some embodiments, the natural rubber includes at least one of RSS1, RSS3#, and RSS5#.

[0012] In some embodiments, the halogenated butyl rubber includes at least one of brominated butyl rubber and chlorinated butyl rubber.

[0013] In some embodiments, the liquid isoprene rubber includes at least one of LIR-50 and LIR-30.

[0014] In some embodiments, the molecular weight of the liquid polyisobutylene rubber is 200-10,000.

[0015] In some embodiments, the tackifying resin includes at least one of C5 petroleum resin, C9 petroleum resin, and alicyclic resin.

[0016] In some embodiments, the softener includes at least one of paraffin oil, cyclohexane oil, and aromatic oil; the carbon black includes at least one of ISAF carbon black N-660, N-550, and N-330; the antioxidant includes antioxidant 1010; the activator includes at least one of zinc oxide and stearic acid (SA); and the vulcanizing agent includes at least one of sulfur and magnesium oxide.

[0017] The present invention also provides a method for preparing the self-repairing rubber composition, comprising the following steps:

[0018] (1) Preliminary mixing stage: natural rubber, butyl rubber and / or halogenated butyl rubber, carbon black, softener, light calcium carbonate, tackifying resin, hydrogenated styrene-isoprene block copolymer, activator, and antioxidant are added to an internal mixer for mixing to obtain a preliminarily mixed rubber material;

[0019] (2) Final mixing stage: the preliminarily mixed rubber, liquid isoprene rubber, liquid polyisobutylene rubber and vulcanizing agent are added to a reaction kettle and stirred and mixed to obtain a rubber composition.

[0020] In some embodiments, in step (1), the rotation speed of the internal mixer is 40 to 80 rpm / min, and the debonding is performed at 130 to 150°C; and / or, in step (2), the stirring speed is 200 to 300 rpm / min, the mixing temperature is 190 to 220°C, and the mixing time is 4 to 8 hours.

[0021] The embodiments of the present invention also provide the use of the self-repairing rubber composition or the self-repairing rubber composition prepared by the above method in a tire. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below. The described embodiments are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0023] The self-repairing rubber composition of the embodiment of the present invention comprises the following components in parts by weight:

[0024] 30-60 parts of natural rubber (NR), 30-60 parts of butyl rubber (IIR) and / or halogenated butyl rubber (HIIR), 10-30 parts of liquid isoprene rubber, 20-80 parts of liquid polyisobutylene rubber, 5-15 parts of carbon black, 10-40 parts of softener, 1-10 parts of light calcium carbonate, 5-10 parts of tackifying resin, 1-5 parts of hydrogenated styrene-isoprene block copolymer (SEPS), 1-8 parts of activator, 0-10 parts of antioxidant and 1-10 parts of vulcanizing agent.

[0025] The self-repairing rubber composition of the embodiment of the present invention can improve the bubbles generated during the spraying process and improve the production quality of the product by using a composition of natural rubber and butyl rubber; by adding low molecular weight liquid isoprene rubber and liquid polyisobutylene with good viscosity and self-repairing properties, the strength of the components can be reduced, so that the rubber composition has good self-repairing properties and softness, and has a good coating effect on pierced foreign matter, and will not separate from the inner wall of the tire and lose its self-repairing properties during continuous use of the tire; by adding tackifying resin and hydrogenated styrene-isoprene block copolymer, hydrogenated styrene- The isoprene block copolymer has a shorter methyl unit series and will not crystallize, so it has good softness and elasticity. When it is used with softening oil, the softness is further enhanced. It shows good tensile strength and cohesion in the composition. The tackifying resin has a higher melting point. When the ambient temperature rises and the strength of the small molecular weight component in the rubber composition decreases, the tackifying resin can still enable the rubber composition to maintain good strength and viscosity, so that the composition still has good self-repairing performance under high temperature conditions; when the rubber composition is used in a tire, it can be quickly repaired after the tire is punctured, without affecting the continued driving of the vehicle.

[0026] In some embodiments, preferably, the natural rubber includes at least one of RSS1, RSS3#, and RSS5#. Further preferably, the natural rubber includes RSS3#.

[0027] In the embodiments of the present invention, a type of natural rubber is preferred. Such natural rubber has relatively less impurities and has a wide source of raw materials that are easily available, thereby reducing production costs.

[0028] In some embodiments, preferably, the halogenated butyl rubber includes at least one of brominated butyl rubber and chlorinated butyl rubber.

[0029] In some embodiments, preferably, the liquid isoprene rubber includes at least one of LIR-50 and LIR-30. Further preferably, the liquid isoprene rubber includes LIR-50.

[0030] In the embodiments of the present invention, the type of liquid isoprene rubber is preferably selected. Such liquid isoprene rubber has a larger relative molecular weight, has a smaller loss of strength at high temperature, and can improve the performance of the rubber composition at high temperature.

[0031] In some embodiments, preferably, the molecular weight of the liquid polyisobutylene rubber is 200 to 10000. Further preferably, the molecular weight of the liquid isoprene rubber is 30000 to 50000.

[0032] In the embodiments of the present invention, the molecular weights of the polyisobutylene rubber and the isoprene rubber are preferably selected, so as to broaden the use temperature range of the rubber component.

[0033] In some embodiments, preferably, the tackifying resin includes at least one of C5 petroleum resin, C9 petroleum resin, and alicyclic resin (DCPC).

[0034] In some embodiments, preferably, the softener includes at least one of paraffin oil, cyclohexane oil, and aromatic oil; the carbon black includes at least one of ISAF carbon black N-660, N-550, and N-330; the antioxidant includes antioxidant 1010; the activator includes at least one of zinc oxide and stearic acid (SA); and the vulcanizing agent includes at least one of sulfur and magnesium oxide.

[0035] The present invention also provides a method for preparing the self-repairing rubber composition, comprising the following steps:

[0036] (1) Preliminary mixing stage: natural rubber, butyl rubber and / or halogenated butyl rubber, carbon black, softener, light calcium carbonate, tackifying resin, hydrogenated styrene-isoprene block copolymer, activator, and antioxidant are added to an internal mixer for mixing to obtain a preliminarily mixed rubber material;

[0037] (2) Final mixing stage: the preliminarily mixed rubber, liquid isoprene rubber, liquid polyisobutylene rubber and vulcanizing agent are added to a reaction kettle and stirred and mixed to obtain a rubber composition.

[0038] In some embodiments, preferably, in the step (1), the rotation speed of the internal mixer is 40 to 80 rpm / min, and the debonding is performed at 130 to 150°C; and / or, in the step (2), the stirring speed is 200 to 300 rpm / min, the mixing temperature is 190 to 220°C, and the mixing time is 4 to 8 hours.

[0039] The embodiments of the present invention also provide the use of the self-repairing rubber composition or the self-repairing rubber composition prepared by the method in a tire.

[0040] The technical solution of the present invention is described in detail below in conjunction with specific embodiments.

[0041] The raw materials used in the embodiments of the present invention are all purchased, wherein: natural rubber (NR) is SCR5 purchased from the manufacturer Banna Shunda; butyl rubber is BB2222 purchased from the manufacturer EXXON; liquid isoprene rubber is LIR-50 purchased from the manufacturer Kuraray; carbon black is N-550 purchased from Shanghai Cabot Corporation; polyisobutylene is V460 purchased from the manufacturer BSF; paraffin oil is PARA2050 purchased from the manufacturer Shanghai Changyu Chemical; tackifying resin is C5 petroleum resin purchased from the manufacturer EXXON; hydrogenated styrene-isoprene block copolymer SEPS W8553 purchased from the manufacturer Zhejiang Zhongli Technology; active agent ZnO purchased from the manufacturer Luchang Chemical; active agent SA purchased from the manufacturer Wilmar Oil; vulcanizing agent sulfur powder (oil content 5%) purchased from the manufacturer Anhui Jinghai Chemical; vulcanizing agent MgO purchased from the manufacturer Concord Chemical; antioxidant is IRGANOX1010 purchased from the manufacturer BSF.

[0042] Example 1

[0043] (1) Preliminary mixing stage: raw rubber, reinforcing agent, antioxidant and activator are added to an internal mixer in batches according to proportions. The speed of the internal mixer is 60 rpm / min. The rubber is discharged at 145°C to obtain a preliminarily mixed rubber material.

[0044] (2) Final mixing stage: The preliminarily mixed rubber, liquid rubber and vulcanizing agent were added into a reactor and mixed in an agitator at a speed of 250 rpm / min and a temperature of 200° C. for 6 h to obtain a rubber composition.

[0045] The ingredients of the rubber composition prepared in Example 1 are shown in Table 1, and the properties are shown in Table 2.

[0046] The preparation methods of Examples 2 to 3 are the same as those of Example 1, except that in the alloy components, the components of the rubber compositions prepared in Examples 2 to 3 are shown in Table 1, and the properties are shown in Table 2.

[0047] Comparative Example 1

[0048] The preparation method of the comparative rubber composition is the same as that of Example 1, except that the composition of the rubber is different, wherein the natural rubber used is 100 parts by weight, the polyisobutylene used is 100 parts by weight, and no butyl rubber, liquid isoprene rubber and SEPS are added.

[0049] Comparative Example 2

[0050] The preparation method of the comparative rubber composition is the same as that of Example 1, except that the composition of the rubber is different and no liquid isoprene rubber is added.

[0051] Comparative Example 3

[0052] The preparation method of the rubber composition of the comparative example is the same as that of Example 1, except that the composition of the rubber is different and no SEPS is added.

[0053] Table 1

[0054]

[0055]

[0056] The rubber compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were uniformly coated on the inner side of a 60 / 70-6.5 tire, with a spraying width equivalent to the crown portion and a spraying thickness of 4 to 7 mm. After spraying, the wheel hub was installed for component testing. The rubber polymers prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were tested for performance, and the results are shown in Table 2:

[0057] (1) Normal temperature self-repair test: Inflate the tire to 300 kPa, and at an ambient temperature of 23 ± 3 °C, pierce the tire with a steel nail with a diameter of ≤ 4 mm. The number of test components is ≥ 3, and each tire is pierced with ≥ 3 nails. After the nails are pierced, the tire is considered qualified if there is no leakage.

[0058] (2) Low temperature extrusion resistance test: After the normal temperature self-repair test, the tire with an air pressure of 300 kPa is placed in a -30°C constant temperature box for 4 hours, then taken out and placed at room temperature for 1 hour before measuring the air pressure. The tire is qualified if the air pressure loss is ≤30 kPa.

[0059] (3) High temperature extrusion resistance test: A tire that has undergone a normal temperature self-repair test and has an air pressure of 300 kPa is placed in a constant temperature box at 80°C for 4 hours and then taken out. The tire is then placed at room temperature for 1 hour and the air pressure is measured. The tire is qualified if the air pressure loss is ≤30 kPa.

[0060] (4) Durability running test: tires that have undergone room temperature self-repair test and have an air pressure of 300 kPa are tested using the test method described in GB / T 9749-2008 and run continuously for 3,000 km at a speed of 25 km / h. The tires are considered qualified if the air pressure loss is ≤30 kPa and the tires do not experience bead unseating, explosion, delamination, cord breakage, core burning, bulging, or separation of the rim from the rubber.

[0061] The tires that have undergone the room temperature self-repair test are installed on electric scooters of the same brand and configuration for outdoor riding tests. The test conditions are: 75kg load, 25km / h speed, riding on urban roads, and mileage recorded by APP. The results are shown in Table 3.

[0062] Table 2

[0063]

[0064] From the results in Table 2, it can be seen that in Examples 1 to 3, suitable materials are used and their dosage is controlled within a suitable range. After being coated on the inner surface of the tire, good self-repairing performance is shown, and good extrusion resistance is shown under low and high temperature environments. After self-repairing, it can continue to travel for more than 3,000 km, showing very good comprehensive performance and meeting the use requirements. In particular, the self-repairing rubber composition of the embodiment of the present invention has excellent high-temperature performance, and for a two-wheeled electric vehicle system with a small wheel diameter tire and a hub motor that has high requirements for the temperature environment, the two-wheeled electric vehicle can still work normally at a higher temperature (80°C).

[0065] In Comparative Example 1, no butyl rubber, liquid isoprene rubber and SEPS were added. Since butyl rubber, liquid isoprene rubber and SEPS all have good thermal stability, the absence of these three substances resulted in the high-temperature extrusion performance of the rubber composition being unqualified. In addition, the absence of butyl rubber makes it easy for bubbles to form during the spraying process of the rubber composition, the absence of liquid isoprene rubber reduces the softness and self-healing performance of the rubber composition, and the absence of SEPS reduces the softness and elasticity of the rubber composition, ultimately resulting in the low-temperature extrusion performance of the rubber composition being unqualified and the inability to complete the durability performance test.

[0066] Comparative Example 2 does not add liquid isoprene rubber, resulting in reduced softness of the rubber composition and unqualified low-temperature anti-extrusion performance, which cannot meet the use requirements at low temperatures.

[0067] Comparative Example 3 does not add SEPS, which reduces the flexibility and elasticity of the rubber composition, and reduces the tensile strength and cohesion of the rubber combination, resulting in unqualified high-temperature extrusion resistance and failure to complete the endurance test.

[0068] Table 3

[0069] project Test car 1 Test car 2 Test car 3 plan Example 1 Example 1 (Premature puncture) Example 2 (Premature puncture) Testing cycle 30day 30day 30day Accumulated test mileage 3000km 3000Km 3000km Initial air pressure 300kpa 300kpa 300kpa End pressure 247kpa 250kpa 245kpa

[0070] It can be seen from Table 3 that the tire sprayed with the composition of the embodiment has comparable air retention after being punctured compared with the tire without being punctured, which indicates that the composition of the embodiment of the present invention has excellent self-repairing performance and can meet the requirements of riding.

[0071] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0072] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A self-repairing rubber composition, characterized in that: The composition comprises the following components by weight: 30-60 parts of natural rubber, 30-60 parts of butyl rubber and / or halogenated butyl rubber, 10-30 parts of liquid isoprene rubber, 20-80 parts of liquid polyisobutylene rubber, 5-15 parts of carbon black, 10-40 parts of softener, 1-10 parts of light calcium carbonate, 5-10 parts of tackifying resin, 1-5 parts of hydrogenated styrene-isoprene block copolymer, 1-8 parts of activator, 0-10 parts of antioxidant and 1-10 parts of vulcanizing agent.

2. The self-repairing rubber composition according to claim 1, characterized in that The natural rubber includes at least one of RSS1, RSS3#, and RSS5#.

3. The self-repairing rubber composition according to claim 1, characterized in that The halogenated butyl rubber includes at least one of brominated butyl rubber and chlorinated butyl rubber.

4. The self-repairing rubber composition according to claim 1, characterized in that The liquid isoprene rubber includes at least one of LIR-50 and LIR-30.

5. The self-repairing rubber composition according to claim 1, characterized in that The molecular weight of the liquid polyisobutylene rubber is 200-10000.

6. The self-repairing rubber composition according to claim 1, characterized in that The tackifying resin includes at least one of C5 petroleum resin, C9 petroleum resin and alicyclic resin.

7. The self-repairing rubber composition according to claim 1, characterized in that The softener includes at least one of paraffin oil, cyclohexane oil, and aromatic oil; the carbon black includes at least one of ISAF carbon black N-660, N-550, and N-330; the antioxidant includes antioxidant 1010; the activator includes at least one of zinc oxide and stearic acid (SA); and the vulcanizing agent includes at least one of sulfur and magnesium oxide.

8. A method for preparing the self-repairing rubber composition according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Preliminary mixing stage: natural rubber, butyl rubber and / or halogenated butyl rubber, carbon black, softener, light calcium carbonate, tackifying resin, hydrogenated styrene-isoprene block copolymer, activator, and antioxidant are added to an internal mixer for mixing to obtain a preliminarily mixed rubber material; (2) Final mixing stage: the preliminarily mixed rubber, liquid isoprene rubber, liquid polyisobutylene rubber and vulcanizing agent are added to a reaction kettle and stirred and mixed to obtain a rubber composition.

9. The method for preparing the self-repairing rubber composition according to claim 8, characterized in that: In the step (1), the rotation speed of the internal mixer is 40 to 80 rpm / min, and the debonding is performed at 130 to 150° C.; and / or, in the step (2), the stirring rotation speed is 200 to 300 rpm / min, the mixing temperature is 190 to 220° C., and the mixing time is 4 to 8 hours.

10. Use of the self-repairing rubber composition according to any one of claims 1 to 7 or the self-repairing rubber composition prepared by the preparation method according to any one of claims 8 to 9 in tires.

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