Organic silicon rubber synthetic leather as well as preparation method and application thereof

Abstract

The invention relates to the technical field of synthetic leather materials, in particular to organic silicon rubber synthetic leather and a preparation method and application thereof, and aims to overcome the technical defects that existing polyurethane and polyvinyl chloride synthetic leather is poor in weather resistance, prone to aging at high temperature and rigid in hand feeling, and common silicon rubber synthetic leather is insufficient in mechanical strength and poor in oil stain resistance. The organic silicon rubber synthetic leather with excellent weather resistance, mechanical strength, soft hand feeling and oil stain resistance is prepared by compounding an MQ silicon resin modified fluorosilicone rubber matrix with a methyl phenyl siloxane toughening system and combining a segmented vulcanization composite process. The synthetic leather is composed of the base cloth layer, the elastic glue layer and the functional surface layer, the bonding force between the layers is strong, and the performance is synergistic; the preparation method is controllable in process, good in repeatability and suitable for industrial production. The synthetic leather can be widely applied to the fields of automotive interiors, outdoor articles, medical instruments and the like, solves the application limitation of traditional synthetic leather under special working conditions, and has remarkable creativity and practicability.

Description

Technical Field

[0001] This invention relates to the field of synthetic leather materials technology, and in particular to an organosilicon rubber synthetic leather, its preparation method and application. Background Technology

[0002] Synthetic leather, as a substitute for natural leather, is widely used in clothing, bags, and automotive interiors due to its advantages such as low cost, controllable performance, and environmental friendliness. Currently, the mainstream synthetic leathers on the market are PU synthetic leather and PVC synthetic leather. However, these types of synthetic leathers have obvious drawbacks: PU synthetic leather has poor weather resistance and is prone to aging and yellowing when exposed to sunlight or high temperatures for a long time; PVC synthetic leather has a stiff feel and is prone to releasing harmful substances such as plasticizers at high temperatures.

[0003] Silicone rubber materials possess excellent high and low temperature resistance, weather resistance, and biocompatibility, making silicone-based synthetic leather a research hotspot. However, existing silicone rubber synthetic leathers generally suffer from insufficient mechanical strength and poor oil resistance, and the bonding strength between the elastic adhesive layer and the base fabric layer and functional surface layer is weak, easily leading to delamination. For example, existing silicone rubber synthetic leathers often use ordinary methyl vinyl silicone rubber as the matrix, which improves weather resistance, but the tensile strength is only 6-8 MPa, failing to meet the high mechanical performance requirements of automotive interiors; at the same time, this synthetic leather lacks oil-resistant surface design, making it difficult to apply in scenarios with high oil content, such as catering and outdoor environments.

[0004] Therefore, based on the relevant technologies mentioned above, there is an urgent need to develop an organosilicon rubber synthetic leather, its preparation method, and its application. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a silicone rubber synthetic leather, its preparation method and application, so as to provide a silicone rubber synthetic leather that has mechanical strength, weather resistance, oil resistance and strong interlayer bonding.

[0006] To achieve the above objectives, the present invention provides an organosilicon rubber synthetic leather, its preparation method, and its application.

[0007] A type of silicone rubber synthetic leather, comprising, from bottom to top, a base fabric layer, an elastic adhesive layer, and a functional surface layer.

[0008] Preferably, the base fabric layer is selected from either polyester needle-punched nonwoven fabric or nylon woven fabric, and the base fabric layer is pretreated with silane coupling agent KH-550 to enhance the interfacial bonding force between the base fabric and the elastic adhesive layer and avoid delamination.

[0009] Preferably, the elastic adhesive layer uses trifluoropropyl-containing methyl vinyl fluorosilicone rubber as the matrix, supplemented with liquid silicone rubber, and simultaneously introduces vinyl-terminated MQ silicone resin to improve mechanical strength, adds methylphenylcyclotrisiloxane to improve material flexibility, uses fumed silica as a reinforcing filler, and uses hydroxyl silicone oil to adjust the processing fluidity of the adhesive. The synergistic effect of the components gives the elastic adhesive layer both high tensile strength and a soft feel.

[0010] Preferably, the functional surface layer uses liquid silicone rubber as the base material, supplemented with fluorosilicone rubber raw rubber, and adds fluoroalkyl modified silicone oil to give the surface oil resistance, nano titanium dioxide to improve UV resistance, and anti-yellowing agent to delay material aging, ensuring that the synthetic leather does not yellow after long-term use.

[0011] The elastic adhesive layer comprises the following raw materials in parts by weight: 100 parts of fluorosilicone rubber raw rubber, 8-12 parts of liquid silicone rubber, 15-25 parts of MQ silicone resin, 8-12 parts of methylphenylcyclotrisiloxane, 5-10 parts of fumed silica, 2-5 parts of hydroxyl silicone oil, and 1.5-3 parts of vulcanizing agent. The functional surface layer comprises the following raw materials in parts by weight: 100 parts liquid silicone rubber, 8-12 parts fluorosilicone rubber raw rubber, 3-8 parts fluoroalkyl modified silicone oil, 2-5 parts nano titanium dioxide, 0.5-1 parts anti-yellowing agent, and 1-2 parts vulcanization aid.

[0012] Preferably, the fluorosilicone rubber raw material is methyl vinyl fluorosilicone rubber containing trifluoropropyl, with a molar mass of 800,000-1,200,000 g / mol.

[0013] Preferably, the M / Q mass ratio of the MQ silicone resin is 0.6-0.8, and the silicone resin ends with vinyl functional groups.

[0014] Preferably, the phenyl molar content in the methylphenylcyclotrisiloxane is 30%-40%.

[0015] Preferably, the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; The vulcanization aid is triallyl isocyanurate.

[0016] The base fabric layer is either polyester needle-punched nonwoven fabric or nylon woven fabric, and the base fabric layer is pretreated with silane coupling agent KH-550.

[0017] Preferably, the process of pretreating the base fabric layer with silane coupling agent KH-550 is as follows: immersing the base fabric in a 2%-3% KH-550 ethanol solution for 10-15 minutes and drying it at 80-90°C.

[0018] A method for preparing silicone rubber synthetic leather includes the following steps: Step S1. Preparation of elastic rubber compound: Put the raw fluorosilicone rubber into a mixer and plasticize it at 80-90℃ for 10-15 minutes. Then, add liquid silicone rubber, MQ silicone resin, fumed silica and hydroxyl silicone oil in sequence and mix for 20-30 minutes. After cooling to below 40℃, add vulcanizing agent and continue mixing for 5-8 minutes. Discharge the material to obtain the elastic rubber compound. Step S2. Preparation of functional surface layer compound: Liquid silicone rubber, fluorosilicone rubber raw rubber, fluoroalkyl modified silicone oil, nano titanium dioxide, anti-yellowing agent and vulcanization aid are put into a high-speed mixer and stirred at 25-30℃ for 15-20 min at a speed of 1500-2000 r / min to obtain functional surface layer compound; Step S3. Composite molding: The elastic adhesive layer prepared in step S1 is coated onto the surface of the pretreated base fabric layer with a coating thickness of 0.2-0.4 mm, and pre-cured at 100-110℃ for 10-15 min; then the functional surface layer adhesive layer prepared in step S2 is coated onto the surface of the pre-cured elastic adhesive layer with a coating thickness of 0.05-0.1 mm. Step S4. Segmented vulcanization: The composite blank is sent into the vulcanization box and vulcanized in segments. First, it is vulcanized at 120℃ for 20 minutes, then the temperature is raised to 160℃ for 10 minutes. After natural cooling to room temperature, the finished silicone rubber synthetic leather is obtained by embossing and cutting.

[0019] Preferably, the heating rate of the segmented vulcanization in step S4 is 5-8°C / min.

[0020] An application of silicone rubber synthetic leather, which is used to prepare automotive seat upholstery, steering wheel covers, outdoor tent fabrics, medical antibacterial mattress covers, and high-end luggage fabrics.

[0021] The beneficial effects of this invention are: This invention provides an organosilicon rubber synthetic leather, its preparation method, and its application. By adding liquid silicone rubber to the elastic adhesive layer and fluorosilicone rubber raw material to the functional surface layer, an interpenetrating cross-linked network (IPN) is formed. Combined with MQ silicone resin modification and a methylphenylcyclotrisiloxane toughening system, the synthetic leather possesses both high mechanical strength and excellent flexibility. Compared with existing ordinary silicone rubber synthetic leather, its tensile strength, elongation at break, and interlayer peel strength are improved, solving the problem of easy delamination between the elastic adhesive layer, functional surface layer, and base fabric layer.

[0022] In the functional surface layer provided by this invention, fluorosilicone rubber raw material and fluoroalkyl modified silicone oil synergistically enhance the density of fluorine groups on the surface. Combined with nano titanium dioxide and anti-yellowing agent, the tensile strength of the product remains at a high level after 1000h of ultraviolet aging. After 100 cycles of high and low temperature (-50℃-180℃), the strength retention rate is ≥91%, far exceeding the weather resistance limit of PU synthetic leather and PVC synthetic leather. The volume change rate after immersion in machine oil at 50℃ for 72h is only 0.9%-1.3%, and there is no stain residue on the surface, solving the problem of poor oil resistance of ordinary silicone rubber synthetic leather.

[0023] The product provided by this invention uses silicone rubber as the core matrix. No harmful substances such as plasticizers are released during production and use, and it has excellent biocompatibility. The synergistic effect of methylphenylcyclotrisiloxane and liquid silicone rubber controls the Shore hardness to 72-75A, resulting in a soft feel and good resilience. This avoids the stiffness of PVC synthetic leather and overcomes the sticky feel of some silicone rubber synthetic leathers. It can directly meet the high requirements of environmental protection and tactile feel for automotive interiors, medical equipment, and other applications.

[0024] The base fabric provided by this invention is pretreated with KH-550 coupling agent, combined with pre-vulcanization and segmented vulcanization processes, which effectively avoids rubber seepage, bubble generation and stress concentration. The surface thickness deviation of the product is ≤0.03mm, the toluene extraction mass loss rate is ≤2.1%, and the vulcanization completeness and molding stability are high. All raw materials used are industrially mass-produced products, the process steps are clear and the parameters are easy to control, which can be adapted to existing synthetic leather production lines for large-scale production, with controllable production costs and high efficiency.

[0025] The product provided by this invention has excellent mechanical strength, weather resistance, oil resistance and environmental friendliness. It can be widely used in many fields such as car seat leather, steering wheel cover, outdoor tent fabric, medical antibacterial mattress cover, and high-end bag fabric. It breaks through the application limitations of traditional synthetic leather in special working conditions and has broad market prospects. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0027] Example 1: A method for preparing silicone rubber synthetic leather, comprising the following steps: S1. Raw material preparation: Methyl vinyl fluorosilicone rubber containing trifluoropropyl with a molar mass of 800,000-1,200,000 g / mol is used as the raw rubber for fluorosilicone rubber; Silicone resins with vinyl functional groups at the ends and an M / Q mass ratio of 0.6-0.8 are used as MQ silicone resins; Methylphenylcyclotrisiloxane with a phenyl molar content of 30%-40% was used as methylphenylcyclotrisiloxane; 2,5-Dimethyl-2,5-bis(tert-butylperoxy)hexane was used as the vulcanizing agent; Triallyl isocyanurate was used as a vulcanization aid. Polyester knitted nonwoven fabric is used as the base fabric layer; The base fabric was immersed in a 2% (w / w) KH-550 ethanol solution for 10 min and then dried at 80°C to obtain the pretreated base fabric. S2. Preparation of elastic rubber layer compound: 100 parts of fluorosilicone rubber raw rubber are put into an internal mixer and plasticized at 80°C for 10 minutes. Then, 8 parts of liquid silicone rubber, 15 parts of MQ silicone resin, 5 parts of fumed silica and 2 parts of hydroxyl silicone oil are added in sequence and mixed for 20 minutes. After cooling to below 40°C, 1.5 parts of vulcanizing agent are added and mixed for another 5 minutes. The elastic rubber layer compound is then obtained by discharging the material. S3. Preparation of functional surface layer compound: 100 parts of liquid silicone rubber, 8 parts of fluorosilicone rubber raw rubber, 3 parts of fluoroalkyl modified silicone oil, 2 parts of nano titanium dioxide, 0.5 parts of anti-yellowing agent and 1 part of vulcanization aid are put into a high-speed mixer and stirred at 25°C for 15 min at a speed of 1500 r / min to obtain the functional surface layer compound. S4. Composite molding: The elastic adhesive layer prepared in step S2 is coated on the surface of the pretreated base fabric layer with a coating thickness of 0.2-0.4 mm, and pre-cured at 100℃ for 10 min; then the functional surface layer adhesive layer prepared in step S3 is coated on the surface of the pre-cured elastic adhesive layer with a coating thickness of 0.05-0.1 mm. S5. Segmented vulcanization: The composite blank is sent into the vulcanization box and vulcanized in segments. First, it is vulcanized at 120℃ for 20 minutes, and then the temperature is increased to 160℃ at a heating rate of 5℃ / min for 10 minutes. After natural cooling to room temperature, the silicone rubber synthetic leather is obtained by embossing and cutting.

[0028] Example 2: A method for preparing silicone rubber synthetic leather, comprising the following steps: S1. Raw material preparation: Methyl vinyl fluorosilicone rubber containing trifluoropropyl with a molar mass of 800,000-1,200,000 g / mol is used as the raw rubber for fluorosilicone rubber; Silicone resins with vinyl functional groups at the ends and an M / Q mass ratio of 0.6-0.8 are used as MQ silicone resins; Methylphenylcyclotrisiloxane with a phenyl molar content of 30%-40% was used as methylphenylcyclotrisiloxane; 2,5-Dimethyl-2,5-bis(tert-butylperoxy)hexane was used as the vulcanizing agent; Triallyl isocyanurate was used as a vulcanization aid. Nylon woven fabric is used as the base layer; The base fabric was immersed in a 2.5% KH-550 ethanol solution for 12 minutes and then dried at 84°C to obtain the pretreated base fabric. S2. Preparation of elastic rubber compound: 100 parts of fluorosilicone rubber raw rubber were put into an internal mixer and plasticized at 84°C for 12 minutes. Then, 9 parts of liquid silicone rubber, 19 parts of MQ silicone resin, 7 parts of fumed silica and 3 parts of hydroxyl silicone oil were added in sequence and mixed for 24 minutes. After cooling to below 40°C, 2.0 parts of vulcanizing agent were added and mixed for another 6 minutes. The elastic rubber compound was then discharged. S3. Preparation of functional surface layer compound: 100 parts of liquid silicone rubber, 9 parts of fluorosilicone rubber raw rubber, 5 parts of fluoroalkyl modified silicone oil, 3 parts of nano titanium dioxide, 0.7 parts of anti-yellowing agent and 1.3 parts of vulcanization aid are put into a high-speed mixer and stirred at 27°C for 17 min at a speed of 1700 r / min to obtain the functional surface layer compound. S4. Composite molding: The elastic adhesive layer prepared in step S2 is coated on the surface of the pretreated base fabric layer with a coating thickness of 0.2-0.4 mm, and pre-cured at 105℃ for 12 min; then the functional surface layer adhesive layer prepared in step S3 is coated on the surface of the pre-cured elastic adhesive layer with a coating thickness of 0.05-0.1 mm. S5. Segmented vulcanization: The composite blank is sent into the vulcanization box and vulcanized in segments. First, it is vulcanized at 120℃ for 20 minutes, and then the temperature is increased to 160℃ at a heating rate of 6℃ / min for 10 minutes. After natural cooling to room temperature, the silicone rubber synthetic leather is obtained by embossing and cutting.

[0029] Example 3: A method for preparing silicone rubber synthetic leather, comprising the following steps: S1. Raw material preparation: Methyl vinyl fluorosilicone rubber containing trifluoropropyl with a molar mass of 800,000-1,200,000 g / mol is used as the raw rubber for fluorosilicone rubber; Silicone resins with vinyl functional groups at the ends and an M / Q mass ratio of 0.6-0.8 are used as MQ silicone resins; Methylphenylcyclotrisiloxane with a phenyl molar content of 30%-40% was used as methylphenylcyclotrisiloxane; 2,5-Dimethyl-2,5-bis(tert-butylperoxy)hexane was used as the vulcanizing agent; Triallyl isocyanurate was used as a vulcanization aid. Polyester knitted nonwoven fabric is used as the base fabric layer; The base fabric was immersed in a 2.8% KH-550 ethanol solution for 14 minutes and then dried at 88°C to obtain the pretreated base fabric. S2. Preparation of elastic rubber compound: 100 parts of fluorosilicone rubber raw rubber were put into an internal mixer and plasticized at 88°C for 14 minutes. Then, 10 parts of liquid silicone rubber, 21 parts of MQ silicone resin, 9 parts of fumed silica and 4 parts of hydroxyl silicone oil were added in sequence and mixed for 28 minutes. After cooling to below 40°C, 2.5 parts of vulcanizing agent were added and mixed for another 7 minutes. The elastic rubber compound was then discharged. S3. Preparation of functional surface layer compound: 100 parts of liquid silicone rubber, 10 parts of fluorosilicone rubber raw rubber, 7 parts of fluoroalkyl modified silicone oil, 4 parts of nano titanium dioxide, 0.9 parts of anti-yellowing agent and 1.6 parts of vulcanization aid are put into a high-speed mixer and stirred at 29℃ for 19 min at a speed of 1900 r / min to obtain the functional surface layer compound. S4. Composite molding: The elastic adhesive layer prepared in step S2 is coated on the surface of the pretreated base fabric layer with a coating thickness of 0.2-0.4 mm, and pre-cured at 108℃ for 14 min; then the functional surface layer adhesive layer prepared in step S3 is coated on the surface of the pre-cured elastic adhesive layer with a coating thickness of 0.05-0.1 mm. S5. Segmented vulcanization: The composite blank is sent into the vulcanization box and vulcanized in segments. First, it is vulcanized at 120℃ for 20 minutes, and then the temperature is increased to 160℃ at a heating rate of 7℃ / min for 10 minutes. After natural cooling to room temperature, the silicone rubber synthetic leather is obtained by embossing and cutting.

[0030] Example 4: A method for preparing silicone rubber synthetic leather, comprising the following steps: S1. Raw material preparation: Methyl vinyl fluorosilicone rubber containing trifluoropropyl with a molar mass of 800,000-1,200,000 g / mol is used as the raw rubber for fluorosilicone rubber; Silicone resins with vinyl functional groups at the ends and an M / Q mass ratio of 0.6-0.8 are used as MQ silicone resins; Methylphenylcyclotrisiloxane with a phenyl molar content of 30%-40% was used as methylphenylcyclotrisiloxane; 2,5-Dimethyl-2,5-bis(tert-butylperoxy)hexane was used as the vulcanizing agent; Triallyl isocyanurate was used as a vulcanization aid. Nylon woven fabric is used as the base layer; The base fabric was immersed in a 3% (w / w) KH-550 ethanol solution for 15 min and then dried at 90°C to obtain the pretreated base fabric. S2. Preparation of elastic rubber compound: 100 parts of fluorosilicone rubber raw rubber are put into an internal mixer and plasticized at 90°C for 15 minutes. Then, 12 parts of liquid silicone rubber, 25 parts of MQ silicone resin, 10 parts of fumed silica and 5 parts of hydroxyl silicone oil are added in sequence and mixed for 30 minutes. After cooling to below 40°C, 3 parts of vulcanizing agent are added and mixed for another 8 minutes. The elastic rubber compound is then discharged. S3. Preparation of functional surface layer compound: 100 parts of liquid silicone rubber, 12 parts of fluorosilicone rubber raw rubber, 8 parts of fluoroalkyl modified silicone oil, 5 parts of nano titanium dioxide, 1 part of anti-yellowing agent and 2 parts of vulcanization aid are put into a high-speed mixer and stirred at 30°C for 20 min at a speed of 2000 r / min to obtain the functional surface layer compound. S4. Composite molding: The elastic adhesive layer prepared in step S2 is coated on the surface of the pretreated base fabric layer with a coating thickness of 0.2-0.4 mm, and pre-cured at 110℃ for 15 min; then the functional surface layer adhesive layer prepared in step S3 is coated on the surface of the pre-cured elastic adhesive layer with a coating thickness of 0.05-0.1 mm. S5. Segmented vulcanization: The composite blank is sent into the vulcanization box and vulcanized in segments. First, it is vulcanized at 120℃ for 20 minutes, and then the temperature is increased to 160℃ at a heating rate of 8℃ / min for 10 minutes. After natural cooling to room temperature, the silicone rubber synthetic leather is obtained by embossing and cutting.

[0031] Comparative Example 1: Compared with Example 1, this comparative example did not add 8 parts of liquid silicone rubber in the preparation process of the elastic adhesive layer of the silicone rubber synthetic leather, nor did it add 8 parts of fluorosilicone rubber raw rubber in the preparation process of the functional surface layer of the silicone rubber synthetic leather. All other steps and parameters were the same, and will not be repeated in this comparative example. Finally, silicone rubber synthetic leather was obtained.

[0032] Comparative Example 2: Compared with Example 1, this comparative example did not add 15 parts of MQ silicone resin in the preparation process of the elastic adhesive layer of the silicone rubber synthetic leather. All other steps and parameters were the same, and will not be repeated in this comparative example. Finally, silicone rubber synthetic leather was obtained.

[0033] Comparative Example 3: Compared with Example 1, this comparative example did not add 8 parts of methylphenylcyclotrisiloxane during the preparation of the elastic adhesive layer of the silicone rubber synthetic leather. All other steps and parameters were the same, and will not be repeated here. The final product was silicone rubber synthetic leather.

[0034] Comparative Example 4: Compared with Example 1, this comparative example did not add 3 parts of fluoroalkyl modified silicone oil in the preparation process of the functional surface layer of the silicone rubber synthetic leather. All other steps and parameters were the same, and will not be repeated in this comparative example. The final product was silicone rubber synthetic leather.

[0035] Comparative Example 5: Compared with Example 1, this comparative example did not perform the pretreatment of "immersing the polyester needle-punched nonwoven fabric in a 2% KH-550 ethanol solution for 10 minutes and drying it at 80°C" during the preparation of the silicone rubber synthetic leather. It was directly used for composite molding. The remaining steps and parameters were the same, and will not be repeated in this comparative example. Finally, silicone rubber synthetic leather was obtained.

[0036] Comparative Example 6: Compared with Example 1, this comparative example only changed the segmented vulcanization to "direct vulcanization at 160℃ for 30 minutes in one go" and canceled the gradient heating mode of "vulcanization at 120℃ for 20 minutes + heating to 160℃ for 10 minutes". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, the silicone rubber synthetic leather was obtained.

[0037] Performance testing: The products prepared in Examples 1-4 and Comparative Examples 1-6 were subjected to the following performance tests: 1. Mechanical performance testing Tensile strength / elongation at break: Dumbbell-shaped No. I specimens were used, with a tensile rate of 500 mm / min. Five specimens were tested in each group, and the average value was taken after removing extreme values.

[0038] Interlayer peel strength: The 180° peel method and the peel rate of 300 mm / min were used to test the bonding force between the elastic adhesive layer and the functional surface layer and between the elastic adhesive layer and the base fabric layer. The minimum value was taken as the characterization value.

[0039] Shore hardness (Type A): Five indentation-free areas are selected evenly on the sample surface for testing, and the average value is taken.

[0040] 2. Weather resistance and environmental stability test UV aging test: Fluorescent UV lamp aging chamber (irradiance 0.89W / (m²)) 2 Tensile strength retention rate was tested after aging at 60℃ and 50% relative humidity for 1000 hours (nm), with an aging period of 60℃ and 50% relative humidity.

[0041] High and low temperature cycling test: A customized extreme environment simulation scheme with a temperature range of -50℃ to 180℃ is used. Each temperature point is kept at the temperature for 1 hour and the cycle is repeated 100 times. The tensile strength retention rate and the change rate of elongation at break are tested after the cycle.

[0042] Oil resistance test: The sample was immersed in 15W-40 diesel engine oil at 50℃ for 72 hours. After drying, the volume change rate was tested, and the stain residue was visually evaluated (no / slight / obvious residue).

[0043] 3. Process and Usage Stability Testing Surface flatness: A laser rangefinder (accuracy ±0.001mm) was used to measure the thickness of 100 random points on the sample surface and the maximum deviation value was calculated.

[0044] Sulfurization completeness: Toluene extraction method, the sample is immersed in toluene for 24 hours, and the mass loss rate after extraction is calculated (≤3% is considered complete sulfurization).

[0045] Yellowing resistance: After 1000 hours of UV aging, the yellowing index ΔE was tested using a colorimeter (≤2.0 is excellent).

[0046] The results are shown in Tables 1-5 below: Table 1 Summary of performance test data for Examples 1-2 Performance indicators Example 1 Example 2 Tensile strength / MPa 15.3 16.8 Elongation at break / % 330 345 interlayer peel strength / N / cm 15.8 17.2 Shore hardness / Type A 72 73 Intensity retention rate after 1000 hours of UV aging / % 92 94 Strength retention rate after 100 high and low temperature cycles / % 91 93 Oil volume change rate after 72 hours of immersion / % 1.3 1.1 Surface thickness deviation / mm 0.03 0.02 Toluene extraction mass loss rate / % 2.1 1.8 Yellowing index ΔE / after 1000h UV exposure 1.2 1.0 Surface stains / after wiping with engine oil none none Table 2 Summary of performance test data for Examples 3-4 Performance indicators Example 3 Example 4 Tensile strength / MPa 17.5 16.2 Elongation at break / % 360 328 interlayer peel strength / N / cm 18.5 16.9 Shore hardness / Type A 75 74 Intensity retention rate after 1000 hours of UV aging / % 96 93 Strength retention rate after 100 high and low temperature cycles / % 95 92 Oil volume change rate after 72 hours of immersion / % 0.9 1.2 Surface thickness deviation / mm 0.02 0.03 Toluene extraction mass loss rate / % 1.5 2.0 Yellowing index ΔE / after 1000h UV exposure 0.8 1.1 Surface stains / after wiping with engine oil none none Table 3 Summary of performance test data for Comparative Examples 1 and 2 Performance indicators Comparative Example 1 Comparative Example 2 Tensile strength / MPa 8.2 9.5 Elongation at break / % 225 250 interlayer peel strength / N / cm 5.1 8.3 Shore hardness / Type A 68 70 Intensity retention rate after 1000 hours of UV aging / % 68 75 Strength retention rate after 100 high and low temperature cycles / % 62 78 Oil volume change rate after 72 hours of immersion / % 4.8 3.2 Surface thickness deviation / mm 0.06 0.05 Toluene extraction mass loss rate / % 4.2 3.8 Yellowing index ΔE / after 1000h UV exposure 3.5 2.8 Surface stains / after wiping with engine oil Obvious residue Slight residue Table 4 Summary of performance test data for Comparative Examples 3-4 Performance indicators Comparative Example 3 Comparative Example 4 Tensile strength / MPa 11.2 12.8 Elongation at break / % 280 305 interlayer peel strength / N / cm 13.2 14.5 Shore hardness / Type A 71 72 Intensity retention rate after 1000 hours of UV aging / % 88 90 Strength retention rate after 100 high and low temperature cycles / % 85 87 Oil volume change rate after 72 hours of immersion / % 2.9 1.8 Surface thickness deviation / mm 0.04 0.03 Toluene extraction mass loss rate / % 2.5 2.3 Yellowing index ΔE / after 1000h UV exposure 1.5 1.3 Surface stains / after wiping with engine oil none none Table 5 Summary of performance test data for Comparative Examples 5-6 Performance indicators Comparative Example 5 Comparative Example 6 Tensile strength / MPa 13.5 14.1 Elongation at break / % 312 308 interlayer peel strength / N / cm 8.7 10.2 Shore hardness / Type A 72 73 Intensity retention rate after 1000 hours of UV aging / % 91 89 Strength retention rate after 100 high and low temperature cycles / % 89 86 Oil volume change rate after 72 hours of immersion / % 1.4 1.5 Surface thickness deviation / mm 0.03 0.08 Toluene extraction mass loss rate / % 2.2 4.7 Yellowing index ΔE / after 1000h UV exposure 1.2 1.4 Surface stains / after wiping with engine oil none none Data Analysis: In this invention, Example 3 exhibits the best overall performance, with a tensile strength of 17.5 MPa, an interlayer peel strength of 18.5 N / cm, and a UV aging retention rate of 96%. The core reason is that under this formulation: ① the crosslinking network density formed by the liquid silicone rubber and MQ silicone resin in the elastic adhesive layer is optimal, with neither dilution effect nor excessive crosslinking; ② the fluoropolymer raw rubber and the fluoroalkyl modified silicone oil in the functional surface layer are synergistically densified by fluorine groups, maximizing oil resistance and weather resistance.

[0047] The performance of Example 4 was lower than that of Example 3. The tensile strength decreased from 17.5 MPa to 16.2 MPa, and the peel strength decreased from 18.5 N / cm to 16.9 N / cm. This was because the excessive liquid silicone rubber diluted the crosslinking density of the elastic adhesive layer, and the high content of fluorosilicone rubber raw rubber increased the viscosity of the functional surface layer, resulting in insufficient diffusion of translayer molecules and a decrease in the integrity of the interpenetrating crosslinking network (IPN).

[0048] Example 2 showed an 8.9% increase in peel strength compared to Example 1 (17.2 vs 15.8 N / cm). This was due to the more developed pores in the nylon woven fabric fibers, allowing for more thorough penetration of the elastic adhesive. Combined with the chemical bridging effect of KH-550 coupling agent, the dual effects of interfacial mechanical interlocking and chemical bonding were stronger.

[0049] In contrast, Comparative Example 1 showed an interlayer peel strength of only 5.1 N / cm (a decrease of 72.4% compared to Example 3), a high and low temperature cycling strength retention rate of 62% (a decrease of 34.7%), and an oil stain resistance volume change rate of 4.8% (an increase of 433.3%). This may be due to the lack of two components that diffuse across layers. The elastic adhesive layer and the functional surface layer are only bonded by surface molecular adsorption and do not form an IPN structure, resulting in extremely weak interfacial forces. At the same time, the fluorine-free silicone rubber raw rubber in the functional surface layer strengthens the density of fluorine groups, making it easy for oil stains to penetrate. The weather resistance is also significantly reduced due to the incomplete cross-linking network.

[0050] The tensile strength of Comparative Example 2 was 9.5 MPa (a decrease of 45.7% compared to Example 3), and the UV aging retention rate was 75% (a decrease of 21.9%). This may be because the vinyl end groups of MQ silicone resin can form a three-dimensional cross-linked network with the fluorosilicone rubber raw material. Its nanoscale particle structure has both physical reinforcement and anti-aging barrier functions. Without this component, the cross-linking density of the elastic adhesive layer is insufficient, and the mechanical strength and UV resistance are significantly weakened.

[0051] The elongation at break of Comparative Example 3 was 280% (a decrease of 22.2% compared to Example 3), and the interlayer peel strength was 13.2 N / cm (a decrease of 28.6%). This may be because the phenyl groups of methylphenylcyclotrisiloxane can disrupt the regularity of the silicone rubber molecular chain, improve the flexibility of the chain segment, and promote the molecular compatibility between the elastic adhesive layer and the functional surface layer. Without the latter, the material's rigidity increases, its flexibility decreases, and the interfacial compatibility weakens, leading to a decrease in peel strength.

[0052] The oil stain resistance volume change rate of Comparative Example 4 was 1.8% (100% higher than Example 3), and the interlayer peel strength was 14.5 N / cm (21.6% lower). This may be because the fluoroalkyl modified silicone oil not only enhances the surface oleophobic properties, but also acts as an interface compatibilizer to promote molecular diffusion between the functional surface layer and the elastic adhesive layer. The lack of fluorine group density on the surface makes it easy for oil stains to be adsorbed, and the decrease in interface compatibility leads to a weakening of the bonding force.

[0053] The interlayer peel strength of Comparative Example 5 was 8.7 N / cm (a decrease of 44.9% compared to Example 1). This may be because the KH-550 coupling agent can form chemical bridge bonds (siloxane bonds) between the base fabric fibers and the elastic adhesive layer. Without pretreatment, the bonding relies solely on physical adsorption, resulting in weak interfacial forces and easy delamination.

[0054] In contrast, Comparative Example 6 had a surface thickness deviation of 0.08 mm (60% exceeding the standard), a toluene extraction mass loss rate of 4.7% (incomplete vulcanization), and a peel strength of 10.2 N / cm (a decrease of 35.4% compared to Example 1). This may be due to the large internal temperature gradient of the rubber compound caused by one-time vulcanization (160℃×30min), which led to the rapid escape of volatile substances and the formation of bubbles. In addition, the cross-linking of the elastic rubber layer and the functional surface layer was not synchronized, resulting in a weak interfacial bond. Segmented vulcanization achieves slow cross-linking through gradient heating, avoiding stress concentration and bubble generation, and ensuring complete vulcanization and good interfacial bond quality.

[0055] In summary, compared with ordinary silicone rubber synthetic leather in the prior art, the tensile strength and interlayer peel strength of the present invention are improved, solving the problems of "low strength and easy delamination" of traditional products; compared with PU synthetic leather, the product of the present invention has improved retention rate and weather resistance; compared with PVC synthetic leather, the product of the present invention has a high and low temperature resistance range of -50℃ to 180℃, and its environmental adaptability is significantly broadened; compared with existing oil-resistant silicone rubber synthetic leather, the product of the present invention has a volume change rate of only 0.9%-1.3%, oil resistance is improved by 62%-82%, and there is no stain residue.

[0056] The high peel strength, high and low temperature cycling retention rate, and low yellowing index of the embodiments 2-3 of this invention can meet the durability requirements of automotive interiors (seat covers, steering wheel covers) under long-term repeated bending and sun exposure.

[0057] Example 3 exhibits an oil stain resistance volume change rate of 0.9% and a UV aging retention rate of 96%, demonstrating its ability to withstand outdoor products (tent fabrics, hiking backpacks) exposed to sunlight, rain, and oil stains, and is easy to clean.

[0058] The low hardness (72-73A), stain-free residue, and biocompatibility of Examples 1-2 meet the needs of medical devices (antibacterial mattress covers) in medical settings for a soft touch and easy disinfection.

[0059] Examples 3-4 exhibit high tensile strength (16.2-17.5MPa) and elongation at break (328%-360%), along with abrasion resistance and deformation resistance, and a feel close to natural leather, making them suitable for the preparation of high-end bag fabrics.

[0060] This invention achieves a synergistic leap in the overall performance of synthetic leather through multi-dimensional innovations, including the formation of an IPN structure by adding liquid silicone rubber to the elastic adhesive layer and fluorosilicone raw rubber to the functional surface layer, MQ silicone resin modification and reinforcement, methylphenylcyclotrisiloxane toughening, fluoroalkyl modified silicone oil for stain resistance, base fabric pretreatment, and segmented vulcanization processes. Compared to existing technologies, the product of this invention achieves double or significant improvements in key performance indicators, fully meeting the stringent requirements of high-end applications such as automotive interiors, outdoor products, and medical equipment, demonstrating outstanding creativity and practicality.

[0061] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0062] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A type of silicone rubber synthetic leather, characterized in that, The silicone rubber synthetic leather comprises, from bottom to top, a base fabric layer, an elastic adhesive layer, and a functional surface layer; The elastic adhesive layer comprises the following raw materials in parts by weight: 100 parts of fluorosilicone rubber raw rubber, 8-12 parts of liquid silicone rubber, 15-25 parts of MQ silicone resin, 8-12 parts of methylphenylcyclotrisiloxane, 5-10 parts of fumed silica, 2-5 parts of hydroxyl silicone oil, and 1.5-3 parts of vulcanizing agent. The functional surface layer comprises the following raw materials in parts by weight: 100 parts liquid silicone rubber, 8-12 parts fluorosilicone rubber raw rubber, 3-8 parts fluoroalkyl modified silicone oil, 2-5 parts nano titanium dioxide, 0.5-1 parts anti-yellowing agent, and 1-2 parts vulcanization aid.

2. The silicone rubber synthetic leather according to claim 1, characterized in that, The fluorosilicone rubber raw material is methyl vinyl fluorosilicone rubber containing trifluoropropyl, with a molar mass of 800,000-1,200,000 g / mol.

3. The silicone rubber synthetic leather according to claim 1, characterized in that, The MQ silicone resin has an M / Q mass ratio of 0.6-0.8, and the silicone resin ends with vinyl functional groups.

4. The silicone rubber synthetic leather according to claim 1, characterized in that, The phenyl molar content in the methylphenylcyclotrisiloxane is 30%-40%.

5. The silicone rubber synthetic leather according to claim 1, characterized in that, The vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; The vulcanization aid is triallyl isocyanurate.

6. The silicone rubber synthetic leather according to claim 1, characterized in that, The base fabric layer is either polyester needle-punched nonwoven fabric or nylon woven fabric, and the base fabric layer is pretreated with silane coupling agent KH-550.

7. The silicone rubber synthetic leather according to claim 6, characterized in that, The pretreatment process is as follows: the base fabric is immersed in a 2%-3% KH-550 ethanol solution for 10-15 minutes and then dried at 80-90℃.

8. A method for preparing an organosilicon rubber synthetic leather according to any one of claims 1-7, characterized in that, Includes the following steps: Step S1. Preparation of elastic rubber compound: Put the raw fluorosilicone rubber into a mixer and plasticize it at 80-90℃ for 10-15 minutes. Then, add liquid silicone rubber, MQ silicone resin, fumed silica and hydroxyl silicone oil in sequence and mix for 20-30 minutes. After cooling to below 40℃, add vulcanizing agent and continue mixing for 5-8 minutes. Discharge the material to obtain the elastic rubber compound. Step S2. Preparation of functional surface layer compound: Liquid silicone rubber, fluorosilicone rubber raw rubber, fluoroalkyl modified silicone oil, nano titanium dioxide, anti-yellowing agent and vulcanization aid are put into a high-speed mixer and stirred at 25-30℃ for 15-20 min at a speed of 1500-2000 r / min to obtain functional surface layer compound; Step S3. Composite molding: The elastic adhesive layer prepared in step S1 is coated onto the surface of the pretreated base fabric layer with a coating thickness of 0.2-0.4 mm, and pre-cured at 100-110℃ for 10-15 min; Subsequently, the functional surface layer adhesive from step S2 is coated onto the surface of the pre-cured elastic adhesive layer, with a coating thickness of 0.05-0.1 mm. Step S4. Segmented vulcanization: The composite blank is sent into the vulcanization box and vulcanized in segments. First, it is vulcanized at 120℃ for 20 minutes, then the temperature is raised to 160℃ for 10 minutes. After natural cooling to room temperature, the finished silicone rubber synthetic leather is obtained by embossing and cutting.

9. The method for preparing organosilicon rubber synthetic leather according to claim 8, characterized in that, The heating rate for the segmented vulcanization in step S4 is 5-8℃ / min.

10. The application of the organosilicon rubber synthetic leather according to any one of claims 1-7, characterized in that, The silicone rubber synthetic leather is used to prepare automotive seat upholstery, steering wheel covers, outdoor tent fabrics, medical antibacterial mattress covers, and high-end luggage fabrics.