High-reliability silicone rubber for airbag coating as well as preparation method and application of silicone rubber

Abstract

The invention discloses excellent-reliability silicone rubber for an airbag coating and a preparation method and application thereof.The excellent-reliability silicone rubber is composed of a component A and a component B. Raw materials of the component A comprise a basic rubber material, a cross-linking agent, a coupling agent and an inhibitor; and the component B comprises the following raw materials: a basic rubber material, a platinum catalyst and titanate. According to the invention, a treating agent is added into a basic rubber material to obtain the silicone rubber for the airbag coating, which has good adhesion to airbag base material cloth PA and PET, wherein the treating agent is one or a mixture of more of trimethylsilanol, hydroxyl silicone oil, vinyl hydroxyl silicone oil and hexamethyldisilazane; and the silicone rubber for the airbag coating has good adhesion to the airbag base material cloth PA and PET, and the treating agent is one or a mixture of more of trimethylsilanol, hydroxyl silicone oil, vinyl hydroxyl silicone oil and hexamethyldisilazane. According to the invention, excellent reliability of the safety airbag base material cloth PA and PET is realized by using a specific process (two-stage treatment process). According to the silicone rubber for the airbag coating prepared by the invention, the silicone resin is treated by the treating agent, so that the Si-OH content in the silicone resin is reduced, and the aging reliability of the liquid silicone rubber coating is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of silicone rubber, and in particular relates to an addition-type silicone rubber composition suitable for automobile airbag coating. Background Art

[0002] Silicone rubber materials have been widely used in various industries due to their good sealing, weather resistance, heat resistance and other properties.

[0003] Curtain airbags (also called side window airbags or side curtain airbags) are a key component of a vehicle's passive safety system, specifically designed to protect occupants' heads from impact in side collisions or rollovers. They are located along the inside of the vehicle's roof (from the A-pillar to the C-pillar), covering the side windows and, in some models, extending to the third row. In the event of a collision (especially a side collision or rollover), they deploy rapidly like a curtain, covering the side windows and protecting passengers. Curtain airbags are a comprehensive safety device consisting of an airbag, inflator, sensors, and control system.

[0004] Curtain airbags are generally manufactured using two different processes. One is the cut-and-sewn, seam-sealed (CSSS) process. This involves bonding two layers of flat fabric cut to specific sizes and shapes (specific structure and pattern) with a seam sealant. After curing at room temperature, the fabric is sewn in place of the seam sealant, completing the curtain airbag fabrication process. The flat fabric is pre-coated with a silicone rubber coating (primarily for pressure retention) on a nylon (PA) or polyester (PET) base fabric.

[0005] CN110892022A discloses an addition-curing silicone rubber composition and an airbag. This composition achieves excellent adhesion and airtightness by combining an organohydrogen polysiloxane, an alkoxysilyl-modified isocyanurate compound, and a condensation catalyst. CN115380083B discloses a silicone rubber composition and a woven material coated with silicone rubber. This composition, by adding a specific intumescent flame retardant and an alkoxysilane containing an epoxy group and / or an alkoxysilane containing a methacrylic group or an acrylic group, not only ensures adhesion between the silicone rubber and the base fabric but also improves flame retardancy. CN119013449A discloses an addition-curing liquid silicone rubber composition for airbags and an airbag. The composition comprises a vinyl organopolysiloxane, an organohydrogen polysiloxane, an organosilicon compound containing one or more functional groups selected from epoxy, isocyanate and (meth)acrylic groups, and an alkoxyorganosiloxane composition. The composition provides an addition-curing liquid silicone rubber for airbags that exhibits anti-slip properties after being applied to an airbag base fabric and cured.

[0006] Summer is characterized by high temperatures and humidity. Under direct sunlight, vehicle interior temperatures can exceed 70°C and humidity levels can exceed 80%RH. A decrease in flex friction resistance after exposure to high temperature and high humidity can significantly impact the safety of drivers and passengers. Flex friction resistance testing, as a means of simulating airbag operating conditions, can effectively reduce product risks during the development phase. However, existing technologies suffer from the following drawbacks:

[0007] 1. The initial bonding strength of ordinary liquid silicone rubber to PA / PET substrate is insufficient, and it is easy to fall off, resulting in reduced airtightness;

[0008] 2. The existing technology can achieve good initial adhesion (flexion friction resistance ≥ 1200 times), but after aging, especially after double 85 (85°C, 85 RH%), the flexion friction resistance decreases significantly;

[0009] 3. In the traditional preparation process, the residual Si-OH groups of silicone resin and the hydroxyl groups on the surface of silica are prone to cause interface damage during the aging process, resulting in a decrease in the flexural friction resistance. Summary of the Invention

[0010] In response to the problems existing in the prior art, the present invention provides a silicone rubber for airbag coating with excellent reliability and a preparation method thereof, which has good flexural friction resistance and reliability and belongs to addition-type silicone rubber.

[0011] To achieve the above object, one embodiment of the present invention adopts the following technical solution:

[0012] The first technical problem solved by the present invention is to provide a silicone rubber for airbag coating, wherein the coating rubber is composed of component A and component B, wherein the raw materials of component A include base rubber, crosslinking agent, coupling agent and inhibitor; the raw materials of component B include base rubber, platinum catalyst and titanate.

[0013] Optionally, the ratio of the raw materials of component A and component B in the coating adhesive is:

[0014] Component A: 100 parts of base rubber, 3-8 parts by mass of crosslinking agent, 2-5 parts by mass of coupling agent and 0.01-0.5 parts by mass of inhibitor;

[0015] Component B: 100 parts of base rubber, 30-100 ppm of platinum catalyst (platinum equivalent), and 0.1-3 parts by mass of titanate.

[0016] The preparation method of the base rubber material comprises the following steps:

[0017] First, 100 parts by mass of vinyl silicone oil, 20-60 parts by mass of silicone resin, and 0.5-2 parts by mass of treating agent are reacted at 70-130°C for 1-3 hours; then the temperature is lowered to below 80°C, and 10-30 parts by mass of fumed silica and 3-5 parts by mass of hexamethyldisilazane are added and mixed at 160-180°C for 1-3 hours, and then vacuum-mixed for 2-5 hours; after cooling, the base rubber compound is obtained by grinding.

[0018] Optionally, in the preparation method of the base rubber compound, the viscosity of the vinyl silicone oil at room temperature (25°C) is 1000-100000 mPa.s, and the vinyl content is 0.04 wt%-0.5wt%, preferably the viscosity is 5000-50000 mPa.s, and the vinyl content is 0.06 wt%-0.2wt%.

[0019] Optionally, in the preparation method of the base rubber compound, the organosilicon resin is a vinyl silicone resin having a vinyl content of 1.0 wt % to 2.0 wt %. Vinyl silicone resins have a good reinforcing effect, and the strength of cured silicone rubber is higher than that of other silicone resins. Using vinyl silicone resins with this vinyl content can also increase the flexural resistance.

[0020] Optionally, in the preparation method of the base rubber material, the treating agent is one or a mixture of trimethylsilanol, hydroxy silicone oil, vinyl hydroxy silicone oil, and hexamethyldisilazane.

[0021] Optionally, in the preparation method of the base rubber compound, the fumed silica is hydrophilic silica, and the specific surface area is 150 to 400 m 2 / g.

[0022] Optionally, the crosslinking agent is hydrogenated silicone oil having a hydrogen content of 0.8 wt% to 1.2 wt%. The hydrogenated silicone oil selected in the present invention has a relatively high hydrogen content. A low hydrogen content will affect the initial adhesion (bending friction).

[0023] Optionally, the coupling agent is at least one of γ-methacryloxypropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, and 1,2-bis(trimethoxysilyl)ethane.

[0024] Optionally, the inhibitor is selected from at least one of 1-ethynyl-1-cyclohexanol, 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane, 3-methyl-1-butyn-3-ol, and 3-methyl-1-pentyn-3-ol. The inhibitor is helpful in controlling the working time of the rubber compound.

[0025] Optionally, the platinum catalyst is at least one of a complex of platinum and divinyltetramethyldisiloxane and a complex of platinum and 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane.

[0026] Optionally, the titanate comprises at least one of tetra-n-butyl titanate (butyl titanate), tetra-tert-butyl titanate, tetraisopropyl titanate, titanium tetraacetylacetonate, and diisopropyl bis(ethyl acetoacetate). The titanate serves as a viscosity-enhancing agent.

[0027] The second technical problem to be solved by the present invention is to provide a method for preparing the silicone rubber for airbag coating, the method comprising the following steps:

[0028] The base rubber, the crosslinking agent, the coupling agent and the inhibitor are mixed at room temperature to obtain component A;

[0029] The base rubber material, the platinum catalyst and the titanate are mixed at room temperature to obtain component B.

[0030] Optionally, the mass ratio of component A to component B is 1:0.1-1.

[0031] The third technical problem addressed by the present invention is to provide a method for applying the aforementioned silicone rubber for airbag coatings. Components A and B are mixed uniformly in a suitable proportion and then applied to the surface of an airbag substrate fabric as required to ensure adhesion of the liquid silicone rubber coating to the substrate and the reliability of the airbag. The silicone rubber for airbag coatings is then vulcanized at a specific temperature to obtain the silicone rubber. The vulcanization conditions are preferably 150-180°C for 1-3 minutes.

[0032] The present invention adds a treatment agent to a base rubber compound to produce a silicone rubber coating for airbags that exhibits excellent adhesion to both PA and PET airbag fabrics. This invention utilizes a specific process (a two-stage treatment process) to achieve excellent reliability with both PA and PET airbag fabrics.

[0033] The silicone rubber for airbag coating provided by the present invention is also an addition-type adhesive silicone rubber. Compared with existing addition-type adhesive silicone rubbers, it has the following advantages:

[0034] 1. The silicone rubber for airbag coating prepared by the present invention has good adhesion to both PA and PET, the base fabrics of the airbag, after curing, and has good reliability.

[0035] 2. The silicone rubber for airbag coating prepared by the present invention is processed by treating the organic silicone resin with a treating agent to reduce the Si-OH content therein, thereby improving the aging reliability of the liquid silicone rubber coating.

[0036] 3. The preparation process of the basic rubber material provided by the present invention is simple, easy to realize industrial production, and has good application prospects. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] Example 1

[0039] First, 100 parts by mass of vinyl silicone oil with a viscosity of 40,000 mPa.s, 50 parts by mass of a silicone resin with a vinyl content of 2 wt%, and 0.5 parts by mass of trimethylsilanol were kneaded in a closed container at 80°C for 1 hour. Then, 10 parts by mass of fumed silica and 3 parts by mass of hexamethyldisilazane were added and kneaded at 160°C for 3 hours, followed by vacuum kneading for 2 hours. After cooling, the mixture was ground to obtain a base rubber compound.

[0040] To 100 parts by mass of the above base rubber material, 3 parts by mass of hydrogenated silicone oil with a hydrogen content of 1.0 wt%, 2 parts by mass of γ-methacryloxypropyltrimethoxysilane, and 0.05 parts by mass of 1-ethynyl-1-cyclohexanol were added and mixed uniformly at 25° C. to obtain component A.

[0041] 100 parts by mass of the same base rubber compound were prepared, and a platinum catalyst (platinum and divinyltetramethyldisiloxane complex) with a platinum equivalent of 30 ppm and 3 parts by mass of butyl titanate were added to the base rubber compound, and the mixture was mixed uniformly at 25°C to obtain component B.

[0042] Components A and B were mixed uniformly at a mass ratio of 100:10 at 25°C, and the hardness, tensile strength, elongation at break, and flexural abrasion resistance with airbag substrates PA and PET fabrics were tested.

[0043] Airbag substrates PA and PET fabrics coated with silicone rubber were cured at 180°C for 1 minute and then placed in a high-temperature, high-humidity, cyclic aging chamber to evaluate product reliability. The test results are shown in Tables 1 and 2.

[0044] Example 2

[0045] First, 100 parts by mass of vinyl silicone oil with a viscosity of 20,000 mPa·s, 60 parts by mass of silicone resin with a vinyl content of 1 wt%, and 1 part by mass of hexamethyldisilazane were kneaded in a closed container at 80°C for 1 hour. 15 parts by mass of fumed silica and 3 parts by mass of hexamethyldisilazane were then added and mixed at 160°C for 3 hours, followed by vacuum mixing for 2 hours. After cooling, the mixture was ground to obtain a base rubber compound.

[0046] To 100 parts by mass of the above base rubber material, 4 parts by mass of hydrogen-containing silicone oil with a hydrogen content of 0.8 wt%, 2 parts by mass of γ-methacryloxypropyltrimethoxysilane, and 0.1 parts by mass of 1-ethynyl-1-cyclohexanol were added and mixed uniformly at 25° C. to obtain component A.

[0047] 100 parts by mass of the same base rubber compound were prepared, and a platinum catalyst (platinum and divinyltetramethyldisiloxane complex) with a platinum equivalent of 50 ppm and 1 part by mass of tetra-tert-butyl titanate were added to the base rubber compound, and the mixture was mixed uniformly at 25°C to obtain component B.

[0048] Components A and B were mixed uniformly at a mass ratio of 100:10 at 25°C, and the hardness, tensile strength, elongation at break, and flexural friction resistance with airbag substrates PA and PET fabrics were tested.

[0049] Airbag substrates PA and PET fabrics coated with liquid silicone rubber were cured at 180°C for 1 minute and then placed in a high-temperature, high-humidity, cyclic aging chamber to evaluate product reliability. The test results are shown in Tables 1 and 2.

[0050] Example 3

[0051] First, 100 parts by weight of vinyl silicone oil with a viscosity of 10,000 mPa.s, 30 parts by weight of a silicone resin with a vinyl content of 3 wt.%, and 2 parts by weight of vinyl hydroxy silicone oil with a vinyl content of 2.5 wt.% were kneaded in a closed container at 120°C for 2 hours. The temperature was lowered to 80°C, and 20 parts by weight of fumed silica and 3 parts by weight of hexamethyldisilazane were added and kneaded at 160°C for 3 hours. The mixture was then vacuum-kneaded for another 2 hours. After cooling, the mixture was ground to obtain a base rubber compound.

[0052] To 100 parts by mass of the above base rubber material, 3 parts by mass of hydrogenated silicone oil with a hydrogen content of 1.2 wt%, 1.5 parts by mass of γ-methacryloxypropyltrimethoxysilane, 0.5 parts by mass of γ-glycidyloxypropyltrimethoxysilane, and 0.4 parts by mass of 1-ethynyl-1-cyclohexanol were added and mixed uniformly at 25°C to obtain component A.

[0053] 100 parts by mass of the same base rubber compound were prepared, and a platinum catalyst (platinum and divinyltetramethyldisiloxane complex) with a platinum equivalent of 80 ppm and 0.5 parts by mass of butyl titanate were added to the base rubber compound, and the mixture was mixed uniformly at 25° C. to obtain component B.

[0054] Components A and B were mixed uniformly at a mass ratio of 100:10 at 25°C, and the hardness, tensile strength, elongation at break, and flexural friction resistance with airbag substrates PA and PET fabrics were tested.

[0055] Airbag substrates PA and PET fabrics coated with liquid silicone rubber were cured at 180°C for 1 minute and then placed in a high-temperature, high-humidity, cyclic aging chamber to evaluate product reliability. The test results are shown in Tables 1 and 2.

[0056] Example 4

[0057] First, 100 parts by mass of vinyl silicone oil with a viscosity of 5000 mPa·s, 60 parts by mass of silicone resin with a vinyl content of 1 wt%, and 1 part by mass of trimethylsilanol were kneaded in a closed container at 80°C for 1 hour. Then, 30 parts by mass of fumed silica and 2 parts by mass of hexamethyldisilazane were added and kneaded at 180°C for 2 hours, followed by vacuum kneading for another 2 hours. After cooling, the mixture was ground to obtain a base rubber compound.

[0058] To 100 parts by mass of the above base rubber material, 5 parts by mass of hydrogen-containing silicone oil with a hydrogen content of 0.8 wt%, 2 parts by mass of γ-methacryloxypropyltrimethoxysilane, and 0.3 parts by mass of 1-ethynyl-1-cyclohexanol were added and mixed uniformly at 25° C. to obtain component A.

[0059] 100 parts by mass of the same base rubber compound was prepared, and a platinum catalyst (platinum and divinyltetramethyldisiloxane complex) with a platinum equivalent of 60 ppm and 3 parts by mass of titanium tetraacetylacetonate were added to the base rubber compound, and the mixture was mixed uniformly at 25° C. to obtain component B.

[0060] Components A and B were mixed uniformly at a mass ratio of 100:10 at 25°C, and the hardness, tensile strength, elongation at break, and flexural friction resistance with airbag substrates PA and PET fabrics were tested.

[0061] Airbag substrates PA and PET fabrics coated with silicone rubber were cured at 180°C for 1 minute and then placed in a high-temperature, high-humidity, cyclic aging chamber to evaluate product reliability. The test results are shown in Tables 1 and 2.

[0062] Comparative Example 1

[0063] First, 100 parts by mass of vinyl silicone oil with a viscosity of 40,000 mPa.s, 50 parts by mass of a silicone resin with a vinyl content of 2 wt%, 10 parts by mass of fumed silica, and 3 parts by mass of hexamethyldisilazane were mixed at 160°C for 3 hours, then vacuum-mixed for 2 hours. After cooling, the mixture was ground to obtain a base rubber compound.

[0064] To 100 parts by mass of the above base rubber material, 3 parts by mass of hydrogenated silicone oil with a hydrogen content of 1.0 wt%, 2 parts by mass of γ-methacryloxypropyltrimethoxysilane, and 0.05 parts by mass of 1-ethynyl-1-cyclohexanol were added and mixed uniformly at 25° C. to obtain component A.

[0065] 100 parts by mass of the same base rubber were prepared, and a platinum catalyst (platinum and divinyltetramethyldisiloxane complex) with a platinum equivalent of 30 ppm and 3 parts by mass of titanate were added to the base rubber, and the mixture was mixed uniformly at 25° C. to obtain component B.

[0066] Components A and B were mixed uniformly at a mass ratio of 100:10 at 25°C, and the hardness, tensile strength, elongation at break, and flexural friction resistance with airbag substrates PA and PET fabrics were tested.

[0067] Airbag substrates PA and PET fabrics coated with liquid silicone rubber were cured at 180°C for 1 minute and then placed in a high-temperature, high-humidity, cyclic aging chamber to evaluate product reliability. The test results are shown in Tables 1 and 2.

[0068] Comparative Example 2

[0069] First, 100 parts by weight of vinyl silicone oil with a viscosity of 20,000 mPa.s and 60 parts by weight of a silicone resin with a vinyl content of 1 wt% were heated to 80°C. Then, 15 parts by weight of fumed silica and 4 parts by weight of hexamethyldisilazane were added and mixed at 160°C for 3 hours. The mixture was then vacuum-mixed for 2 hours. After cooling, the mixture was ground to obtain a base rubber compound.

[0070] To 100 parts by mass of the above base rubber material, 4 parts by mass of hydrogen-containing silicone oil with a hydrogen content of 0.8 wt%, 2 parts by mass of γ-methacryloxypropyltrimethoxysilane, and 0.1 parts by mass of 1-ethynyl-1-cyclohexanol were added and mixed uniformly at 25° C. to obtain component A.

[0071] 100 parts by mass of the same base rubber compound were prepared, and a platinum catalyst (platinum and divinyltetramethyldisiloxane complex) with a platinum equivalent of 50 ppm and 1 part by mass of tetra-tert-butyl titanate were added to the base rubber compound, and the mixture was mixed uniformly at 25°C to obtain component B.

[0072] Components A and B were mixed uniformly at a mass ratio of 100:10 at 25°C, and the hardness, tensile strength, elongation at break, and flexural friction resistance with airbag substrates PA and PET fabrics were tested.

[0073] Airbag substrates PA and PET fabrics coated with liquid silicone rubber were cured at 180°C for 1 minute and then placed in a high-temperature, high-humidity, cyclic aging chamber to evaluate product reliability. The test results are shown in Tables 1 and 2.

[0074] Comparative Example 3

[0075] First, 100 parts by mass of vinyl silicone oil with a viscosity of 40,000 mPa.s, 50 parts by mass of methyl silicone resin, and 2 parts by mass of trimethylsilanol were kneaded in a closed container at 80°C for 1 hour. Then, 10 parts by mass of fumed silica and 3 parts by mass of hexamethyldisilazane were added and mixed at 160°C for 3 hours, followed by vacuum mixing for 2 hours. After cooling, the mixture was ground to obtain a base rubber compound.

[0076] To 100 parts by mass of the above base rubber material, 3 parts by mass of hydrogenated silicone oil with a hydrogen content of 1.0 wt%, 2 parts by mass of γ-methacryloxypropyltrimethoxysilane, and 0.05 parts by mass of 1-ethynyl-1-cyclohexanol were added and mixed uniformly at 25° C. to obtain component A.

[0077] 100 parts by mass of the same base rubber compound were prepared, and a platinum catalyst (platinum and divinyltetramethyldisiloxane complex) with a platinum equivalent of 30 ppm and 3 parts by mass of butyl titanate were added to the base rubber compound, and the mixture was mixed uniformly at 25°C to obtain component B.

[0078] Components A and B were mixed uniformly at a mass ratio of 100:10 at 25°C, and the hardness, tensile strength, elongation at break, and flexural friction resistance with airbag substrates PA and PET fabrics were tested.

[0079] Airbag substrates PA and PET fabrics coated with silicone rubber were cured at 180°C for 1 minute and then placed in a high-temperature, high-humidity, cyclic aging chamber to evaluate product reliability. The test results are shown in Tables 1 and 2.

[0080] Comparative Example 4

[0081] First, 100 parts by mass of vinyl silicone oil with a viscosity of 40,000 mPa.s, 50 parts by mass of a silicone resin with a vinyl content of 2 wt%, and 0.5 parts by mass of trimethylsilanol were kneaded in a closed container at 80°C for 1 hour. Then, 10 parts by mass of fumed silica and 3 parts by mass of hexamethyldisilazane were added and kneaded at 160°C for 3 hours, followed by vacuum kneading for 2 hours. After cooling, the mixture was ground to obtain a base rubber compound.

[0082] To 100 parts by mass of the above base rubber material, 5 parts by mass of hydrogenated silicone oil with a hydrogen content of 0.5 wt%, 2 parts by mass of γ-methacryloxypropyltrimethoxysilane, and 0.05 parts by mass of 1-ethynyl-1-cyclohexanol were added and mixed uniformly at 25° C. to obtain component A.

[0083] 100 parts by mass of the same base rubber compound were prepared, and a platinum catalyst (platinum and divinyltetramethyldisiloxane complex) with a platinum equivalent of 30 ppm and 3 parts by mass of butyl titanate were added to the base rubber compound, and the mixture was mixed uniformly at 25°C to obtain component B.

[0084] Components A and B were mixed uniformly at a mass ratio of 100:10 at 25°C, and the hardness, tensile strength, elongation at break, and flexural friction resistance with airbag substrates PA and PET fabrics were tested.

[0085] Airbag substrates PA and PET fabrics coated with silicone rubber were cured at 180°C for 1 minute and then placed in a high-temperature, high-humidity, cyclic aging chamber to evaluate product reliability. The test results are shown in Tables 1 and 2.

[0086] Table 1 Main basic properties of adhesive liquid silicone rubber for airbag coating

[0087]

[0088] Table 2 Reliability test of adhesive liquid silicone rubber for airbag coating

[0089]

[0090] Note: High temperature aging conditions are 105°C × 408h. High temperature and high humidity conditions are 85°C, 85 RH.%, and aging time is 408h. Cyclic aging conditions: (1) -40°C × 29h; (2) 22°C, 95RH% × 19h; (3) 105°C × 29h; (4) 22°C, 95RH% × 19h. A total of 3 cycles.

[0091] The test methods for sample performance in Table 1 and Table 2 are as follows:

[0092] 1. Determine the hardness of silicone rubber for airbag coating according to ASTM D2240;

[0093] 2. Determine the tensile strength and elongation at break of silicone rubber for airbag coating according to GB / T 528;

[0094] 3. Determination of the flexural friction resistance of silicone rubber for airbag coating according to ISO 5981:

[0095] 4. Reliability evaluation method:

[0096] Evaluate the changes in the hardness and flexural friction resistance of silicone rubber after high temperature, high temperature and high humidity, and high and low temperature cyclic aging. If the flexural friction resistance is not less than 1000 times, it is considered to have good reliability.

[0097] Analyze the test results in Table 1 and Table 2:

[0098] Comparative Example 1 does not pre-treat the silicone resin with a treatment agent. Instead, the silicone resin, white carbon black, and the treatment agent hexamethyldisilazane are directly mixed and then kneaded together. A comparison of Example 1 and Comparative Example 1 shows that without pre-treating the silicone resin with a treatment agent, the flex friction resistance of the coating adhesive on airbag substrates PA and PET fabric is reduced. In particular, after aging at high temperature and high humidity, the flex friction resistance of the coating adhesive is significantly reduced, no longer meeting the requirements. However, the coating adhesive prepared using the silicone resin oil treated using the patented process showed no reduction in flex friction resistance after aging at high temperature, high temperature and humidity, and high and low temperature cycles. This indicates that treating the silicone resin with trimethylsilanol improves the flex friction resistance of the coating adhesive, especially after aging at high temperature and high humidity. This may be due to the residual -OH groups in the silicone resin, which makes adhesion more susceptible to damage during reliability testing, leading to the decrease in flex friction resistance.

[0099] Comparative Example 2 also omitted pre-mixing the silicone resin with a treatment agent. Instead, the silicone resin, silica, and the treatment agent, hexamethyldisilazane, were directly mixed and then mixed together. However, the amount of hexamethyldisilazane used in Comparative Example 2 was increased. A comparison of Example 2 and Comparative Example 2 reveals that simply heating the resin and silicone oil and then adding a higher level of hexamethyldisilazane significantly reduces the flex friction resistance of the airbag substrate PA and PET fabric. Furthermore, after aging under high-temperature, high-humidity, and high-low-temperature cycles, the flex friction resistance no longer meets the required standards. This may be due to the higher reactivity of the -OH group in silica, which allows the added hexamethyldisilazane to react preferentially with silica.

[0100] Comparative Example 3 does not use a vinyl-containing silicone resin, but instead uses a methyl silicone resin. A comparison of Example 1 and Comparative Example 3 shows that even using the patented process, the methyl silicone resin's insufficient initial strength causes it to fail in the bending friction test, thus failing to meet the requirements.

[0101] Comparative Example 4 uses a hydrogenated silicone oil with a lower hydrogen content. A comparison of Example 1 and Comparative Example 4 shows that even after treatment using the process employed in this patent, if the hydrogenated silicone oil has a lower hydrogen content, the bending friction is significantly lower under the curing conditions of 180°C for 1 minute. This may be because the hydrogen content directly affects the adhesion between the silicone rubber and the substrate, and thus the flexural friction resistance.

[0102] Compared with commercial joint venture and imported products, the silicone rubber coating products produced by the process of the present invention have better reliability.

[0103] The reason for the reliability reduction of the prior art is that the -OH in the silicone resin is more easily destroyed during the aging process, especially high temperature and high humidity aging. The -OH in the white carbon black has higher activity, so the -OH in the silicone resin needs to be treated separately first. After the process of the present patent, both the silicone resin and the white carbon black are well treated, so they have more excellent reliability.

[0104] While the application has been described with reference to illustrative embodiments thereof, it is understood that the application is not limited thereby, but is amenable to numerous changes and modifications, which will come readily to those skilled in the art. More specifically, various combinations of the constituent components and / or layout of the subject combination layout can be varied and modified, while still falling within the scope of the present disclosure. Other uses will also be apparent to those of ordinary skill in the art.

Claims

1. A silicone rubber for airbag coating with excellent reliability, characterized in that: It consists of component A and component B, and the raw material ratio of each component is: Component A: 100 parts of base rubber, 3-8 parts by mass of crosslinking agent, 2-5 parts by mass of coupling agent and 0.01-0.5 parts by mass of inhibitor; Component B: 100 parts of base rubber, 30-100 ppm of platinum catalyst (platinum equivalent), and 0.1-3 parts by mass of titanate.

2. The silicone rubber for airbag coating having excellent reliability according to claim 1, characterized in that The preparation method of the base rubber material comprises the following steps: First, 100 parts by mass of vinyl silicone oil, 20-60 parts by mass of silicone resin, and 0.5-2 parts by mass of treating agent are reacted at 70-130°C for 1-3 hours; then the temperature is lowered to below 80°C, and 10-30 parts by mass of fumed silica and 3-5 parts by mass of hexamethyldisilazane are added and mixed at 160-180°C for 1-3 hours, and then vacuum-mixed for 2-5 hours; after cooling, the base rubber compound is obtained by grinding.

3. The silicone rubber for airbag coating having excellent reliability according to claim 2, characterized in that The treatment agent is one of trimethylsilanol, hydroxy silicone oil, vinyl hydroxy silicone oil and hexamethyldisilazane or a mixture of several of them.

4. The silicone rubber for airbag coating having excellent reliability according to claim 3, characterized in that The organic silicone resin is a vinyl silicone resin with a vinyl content of 1.0 wt % to 2.0 wt %; the viscosity of the vinyl silicone oil at room temperature is 5000 to 50000 mPa.s; and the fumed silica is hydrophilic silica.

5. The silicone rubber for airbag coating having excellent reliability according to claim 1, characterized in that The cross-linking agent is hydrogen-containing silicone oil, and the hydrogen content thereof is 0.8 wt% to 1.2 wt%.

6. The silicone rubber for airbag coating having excellent reliability according to claim 1, characterized in that The coupling agent is at least one of γ-methacryloxypropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, and 1,2-bis(trimethoxysilyl)ethane.

7. The silicone rubber for airbag coating having excellent reliability according to claim 1, characterized in that The inhibitor is selected from at least one of 1-ethynyl-1-cyclohexanol, 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane, 3-methyl-1-butyn-3-ol, and 3-methyl-1-pentyn-3-ol.

8. The silicone rubber for airbag coating having excellent reliability according to claim 1, characterized in that The platinum catalyst is at least one of a complex of platinum and divinyltetramethyldisiloxane and a complex of platinum and 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane; The titanate is at least one selected from tetra-n-butyl titanate (butyl titanate), tetra-tert-butyl titanate, tetraisopropyl titanate, titanium tetraacetylacetonate, and diisopropyl bis(ethyl acetoacetate) titanate.

9. The method for preparing the silicone rubber for airbag coating with excellent reliability according to any one of claims 1 to 8, characterized in that: The steps include: The base rubber, the crosslinking agent, the coupling agent and the inhibitor are mixed at room temperature to obtain component A; The base rubber material, platinum catalyst and titanate are mixed at room temperature to obtain component B; The mass ratio of component A to component B is 1:0.1~1.

10. The method for using the silicone rubber for airbag coating with excellent reliability according to any one of claims 1 to 8, characterized in that: After evenly mixing component A and component B in a mass ratio of 1:0.1-1, apply the mixture on the surface of the airbag substrate fabric, and then vulcanize at 150-180°C for 1-3 minutes.

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