Organosilicon coating adhesive suitable for OPW one-piece type side air curtain safety air bag, preparation method and application

Abstract

The invention relates to the technical field of high polymer materials, in particular to an organic silicon coating adhesive suitable for an OPW one-piece type side air curtain safety air bag and a preparation method and application of the organic silicon coating adhesive. The organic silicon coating adhesive comprises vinyl-terminated polydimethylsiloxane, a hydrogen-containing silicone oil cross-linking agent, a platinum catalyst, a bio-based tackifier, a reactive reinforcing filler and an inhibitor, wherein the bio-based tackifier is hydrogenated rosin resin grafted and modified by an itaconic anhydride derivative; the reaction type reinforcing filler is a micro-nano filler with vinyl after surface treatment. Through the synergistic effect of the bio-based tackifier and the reactive reinforcing filler, excellent adhesion, flame retardance and mechanical properties are ensured, and meanwhile, the air tightness and pressure maintaining performance of the OPW air bag and the efficiency of the production process are ensured by controlling the rheological property and the reaction speed of the product.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to an organosilicon coating composition for automotive airbag fabric and its preparation method, particularly suitable for OPW (One*Piece Woven) one-piece side curtain airbags based on PET (polyethylene terephthalate) substrate. Background Technology

[0002] Airbags are a core component of automotive passive safety systems. Their fabric base needs to be coated with a layer of silicone rubber to achieve airtightness, heat resistance, flexibility, and good folding performance. With the increasing effectiveness of curtain airbags in protecting occupants during side collisions and rollovers, the 2021 C-NCAP new car evaluation introduced an assessment of side curtain airbag pressure retention performance. The pressure retention performance of OPW airbag bags has become an important indicator in the development and production process design.

[0003] The main reason for air leakage in OPW airbag fabric is the presence of gaps in the fabric structure itself, such as at the intersections of warp and weft yarns and between warp and weft fibers. Under the impact of high-temperature and high-pressure airflow, airflow passes through these gaps. Current technologies generally improve airtightness by increasing fabric density or coating weight, but this increases cost, fabric thickness, and weight, affecting the folded volume. Furthermore, the adhesion of the PET substrate to the silicone coating has long been a technical challenge due to its high crystallinity and low surface polarity.

[0004] Currently, mainstream technologies are monopolized by companies such as Dow, Elkem, and Shin-Etsu. Their patents (such as CN108291112B and CN103131327B) mainly focus on using specific organotitanium / zirconium compounds, epoxy-functionalized siloxanes, and phosphononitrile compounds as key additives to solve adhesion, flame retardancy, and anti-blocking issues. However, these technical solutions have the following drawbacks: 1) They heavily rely on petroleum-based raw materials; 2) Some additives used (such as some organotitanium compounds) may pose health and environmental risks; 3) Complex formulation systems lead to high production costs and difficulties in process control; 4) Their formulation design and process parameters are mainly optimized for nylon (PA66), and their compatibility with PET substrates is not optimal.

[0005] Therefore, there is an urgent need in this field for a novel silicone coating adhesive technology that is environmentally friendly, has a simplified formulation, and is specifically designed for PET substrates. Summary of the Invention

[0006] The purpose of this invention is to provide an airbag silicone coating adhesive based on bio-based tackifiers and reactive reinforcing fillers. By using novel bio-based tackifiers and innovative filler technology, it ensures excellent adhesion, flame retardancy and mechanical properties while completely avoiding the use of traditional petroleum-based key additives in existing patents.

[0007] Another object of the present invention is to provide a method for preparing such an organosilicon coating adhesive.

[0008] Another object of the present invention is to provide the application of this silicone coating adhesive in the manufacture of airbags.

[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides an organosilicon coating adhesive suitable for OPW one-piece side curtain airbags, comprising, by weight: 100 parts of vinyl-terminated polydimethylsiloxane; a hydrogen-containing silicone oil crosslinking agent; a platinum catalyst, 10-200 ppm (Pt); 5-25 parts of a bio-based tackifier; 10-40 parts of a reactive reinforcing filler; and 0.01-0.1 parts of an inhibitor.

[0011] The molar ratio of Si-H in the hydrogen-containing silicone oil crosslinking agent to vinyl in the vinyl-terminated polydimethylsiloxane is (1.0-1.5):1.

[0012] The bio-based tackifier is a bio-based itaconic anhydride graft-modified hydrogenated rosin resin.

[0013] The reactive reinforcing filler is a micro / nano filler with vinyl groups on its surface after treatment.

[0014] In some specific embodiments, the bio-based thickener is synthesized from bio-based itaconic anhydride and hydrogenated rosin via a Diels-Alder reaction, with an acid value of 130-180 mg KOH / g.

[0015] In some specific embodiments, the micro / nano filler in the reactive reinforcing filler is one or more of silicon dioxide, boron nitride, and silicone resin powder, with a particle size of 10-1000 nm, preferably 50-500 nm, and a surface vinyl modification rate of 0.5-2.0 mmol / g.

[0016] In some specific embodiments, the viscosity of the vinyl-terminated polydimethylsiloxane is 10,000-100,000 mPa·s, preferably 40,000-60,000 mPa·s.

[0017] In some specific implementations, the hydrogen-containing silicone oil crosslinking agent contains at least 0.05 mol / 100g of silane and has a viscosity of 5-20 mPa·s.

[0018] In some specific implementation schemes, the inhibitor used is one or more of ethynylcyclohexanol, dimethyl maleate, and methylbutynol, with ethynylcyclohexanol being preferred.

[0019] On the other hand, a method for preparing the aforementioned silicone coating adhesive includes the following steps:

[0020] 1) Under inert gas protection, the vinyl-terminated polydimethylsiloxane, bio-based tackifier, reactive reinforcing filler and inhibitor are added to a planetary mixer and stirred under vacuum at 80-100°C for 1-2 hours to fully mix the components and remove moisture and air bubbles to obtain component A.

[0021] 2) Mix the hydrogen-containing silicone oil with a portion of the solvent and stir until homogeneous to obtain component B;

[0022] 3) Before use, mix components A, B and catalyst in proportion and adjust to the required working viscosity with the remaining solvent.

[0023] On another front, the aforementioned silicone coating adhesive is used in the preparation of PET-based OPW one-piece side curtain airbags.

[0024] In some specific implementation schemes, the silicone coating adhesive in the preparation process of PET substrate OPW one-piece side curtain airbags includes: coating a first coating on PET fabric with a basis weight of 40-70 g / m². 2 Baking at 160-200℃ for 1-3 minutes; applying a second coating on top of the first coating, with a basis weight of 5-15 g / m². 2 Bake at 160-200℃ for 1-3 minutes.

[0025] In some specific implementations, in the PET substrate OPW one-piece side curtain airbag prepared with the aforementioned silicone coating adhesive, based on PET fabric, the total coating weight is 45-85 g / m². 2 Pressure retention rate (70kPa, 12s) ≥80%, peel strength ≥80N / cm.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] Compared to mainstream technologies monopolized by companies such as Dow, Elkem, and Shin-Etsu, this invention solves the problems of adhesion, flame retardancy, and anti-blocking without using specific organotitanium / zirconium compounds, epoxy-functionalized siloxanes, phosphononitrile compounds, etc., as key additives.

[0028] The silicone coating adhesive for airbags of the present invention does not rely on petroleum-based raw materials and uses bio-based tackifiers, making it environmentally friendly; the formulation system is simple, the production cost is low, and the process is relatively simple; the formulation design of the present invention is mainly for PET, the preferred substrate of OPW, and has high compatibility. Detailed Implementation

[0029] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0031] The silicone coating adhesive of the present invention, applicable to OPW one-piece side curtain airbags, comprises the following components by weight:

[0032] Base polymer: 100 parts of vinyl-terminated polydimethylsiloxane;

[0033] Hydrogen-containing silicone oil crosslinking agent, wherein the molar ratio of the silicon-hydrogen bond to the vinyl group in the base polymer is (1.0-1.5):1, such as 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, etc.;

[0034] The platinum catalyst, calculated as platinum metal, is added in an amount of 10-200 ppm of the base polymer, such as 10 ppm, 20 ppm, 50 ppm, 80 ppm, 100 ppm, 120 ppm, 150 ppm, 180 ppm, 200 ppm, etc.

[0035] 5-25 parts of a bio-based tackifier, such as 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 parts, wherein the bio-based tackifier is a hydrogenated rosin resin grafted with an itaconic anhydride derivative. The bio-based tackifier is synthesized by a Diels-Alder reaction between bio-based itaconic anhydride and hydrogenated rosin, and its molecule simultaneously contains a carboxylic anhydride group and a hydrogenated phenanthrene ring structure.

[0036] 10-40 parts of reactive reinforcing filler, such as 11, 12, 15, 18, 20, 23, 25, 27, 30, 33, 35, 38, 40 parts, etc., wherein the reactive reinforcing filler is a micro / nano filler with vinyl groups on its surface after treatment.

[0037] Inhibitor: Ethynylcyclohexanol 0.01-0.1 parts, such as 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1 parts, etc.;

[0038] Solvent: Methylsiloxane solvent, added as needed, to adjust the viscosity to 5000*15000 mPa.s suitable for coating.

[0039] The preparation method of the above-mentioned organosilicon airbag coating adhesive of the present invention includes the following steps:

[0040] 1) Under inert gas protection, the vinyl-terminated polydimethylsiloxane, bio-based tackifier, reactive reinforcing filler and inhibitor are added to a planetary mixer and stirred under vacuum at 80-100°C for 1-2 hours to fully mix the components and remove moisture and air bubbles to obtain component A.

[0041] 2) Mix the hydrogen-containing silicone oil with a portion of the solvent and stir until homogeneous to obtain component B;

[0042] 3) Before use, mix components A, B and catalyst in proportion and adjust to the required working viscosity with the remaining solvent.

[0043] This invention provides a coating process for PET substrate OPW one-piece side curtain airbags, comprising the following steps:

[0044] S1: Apply the first coating to the PET fabric using the above-mentioned coating adhesive (viscosity adjusted to 13-20 Pa·s), with a coating basis weight of 40-70 g / m². 2 .

[0045] S2: Baking is carried out through several sections of continuous heat-setting ovens, with the baking temperature increasing sequentially from 100-160℃; the baking speed is 20-30 yd / min.

[0046] S3: Apply a second coating layer over the first coating layer, using the same coating adhesive (viscosity adjusted to 200-400 Pa·s), with a basis weight of 5-15 g / m³. 2 .

[0047] S4: Then bake through several sections of continuous heat-setting oven, with the baking temperature increasing sequentially from 160-205℃; the baking speed is 15-20 yd / min.

[0048] Unless otherwise specified, all viscosities in this invention refer to the temperature at which the test was conducted at room temperature, such as 25°C. There are no particular restrictions on the viscosity testing method, such as using a Brookfield LV viscometer, a #7 spindle, and 5 rpm.

[0049] The present invention will be specifically described below through embodiments, but the present invention is not limited thereto.

[0050] The main sources of raw materials involved in the following embodiments are as follows:

[0051] Vinyl-terminated polydimethylsiloxane, Hubei Xinghua Silicon Materials Co., Ltd.;

[0052] Vinyl-modified boron nitride nanosheets, Dandong Chemical Research Institute Co., Ltd.;

[0053] Ethynylcyclohexanol, Wuhan Xinyang Ruihe Chemical Technology Co., Ltd.;

[0054] Hydrogen-containing silicone oil, Zhejiang Runhe Organosilicon New Materials Co., Ltd.;

[0055] Methylsiloxane, Zhejiang Hongyuan New Material Technology Co., Ltd.;

[0056] Platinum catalyst, Guangzhou Silicon Friends New Materials Technology Co., Ltd.

[0057] Vinyl-modified silica, Shandong Kason New Materials Co., Ltd.

[0058] Vinyl-modified silicone resin powder, Shandong Dayi Chemical Co., Ltd.;

[0059] Hydrogenated rosin, Nantong Runfeng Petrochemical Co., Ltd.;

[0060] Itaconic anhydride, Sinopharm Chemical Reagent Co., Ltd.;

[0061] Toluene, Sinopharm Chemical Reagent Co., Ltd.;

[0062] p-Toluenesulfonic acid, Sinopharm Chemical Reagent Co., Ltd.;

[0063] Preparation method of itaconic anhydride hydrogenated rosin adduct: In a glove box under nitrogen protection, 0.035 mol of pretreated hydrogenated rosin was added to a three-necked flask equipped with a mechanical stirrer, reflux condenser, and thermometer. Under nitrogen protection, 50 mL of xylene was added, and the temperature was slowly raised to 120 °C. Then, 0.042 mol of itaconic anhydride was added dropwise. After the addition was complete, 0.1 g of p-toluenesulfonic acid was slowly added, and stirring was continued for 15 min. The temperature was then raised to 125 °C. The reaction was maintained at this temperature for 3-4 hours. During the reaction, the acid value of the product was continuously monitored by titration. By adjusting the reaction time, products with acid values ​​of 130, 150, 160, and 180 mg KOH / g were obtained. After the reaction was completed, insoluble matter and solvent were removed by filtration, the product was purified, and dried at 50 °C and -0.09 MPa for later use.

[0064] The pretreatment of hydrogenated rosin involves refluxing with anhydrous ethanol 2-3 times to remove pigments and impurities, resulting in clear and transparent hydrogenated rosin.

[0065] Unless otherwise specified, all other raw materials and reagents can be purchased through commercial channels.

[0066] The main test methods involved in the following embodiments are as follows:

[0067] Peel strength: Test standard reference ASTM D3330;

[0068] Burning rate: Test standard reference FMVSS 302;

[0069] Pressure retention rate (70kPa, 12s): The airbag is inflated to 70kPa pressure, left to stand for 12s, and the pressure is taken. The pressure retention rate is the pressure reading at this time divided by the initial pressure reading of 70kPa.

[0070] Example 1

[0071] <Coating Adhesive Preparation>

[0072] Preparation of Component A: Under nitrogen protection, 100 parts of vinyl-terminated polydimethylsiloxane (viscosity 10,000 mPa.s), 20 parts of itaconic anhydride hydrogenated rosin adduct (acid value 150 mg KOH / g), 30 parts of vinyl-modified boron nitride nanosheets (particle size 100 nm, vinyl content 0.05 mmol / g), and 0.05 parts of ethynylcyclohexanol were added to a planetary mixer and stirred at 90 °C and -0.095 MPa for 1.5 hours. After cooling, Component A was obtained.

[0073] Preparation of Component B: Hydrogen-containing silicone oil (viscosity 5 mPa·s) with a molar ratio of 1.2:1 to vinyl groups in Component A is mixed with an appropriate amount of methylsiloxane solvent to obtain Component B.

[0074] Preparation of coating adhesive solution: When using, take 100 parts of component A, add 1.5 parts of platinum catalyst (platinum content 50ppm), mix well, then add the corresponding amount of component B, and dilute with methylsiloxane solvent to adjust the viscosity.

[0075] Coating Process

[0076] First coating: Adjust the viscosity of the above adhesive solution to 18 Pa·s with a solvent, and apply it to the PET OPW airbag fabric. The coating weight is 40 g / m². 2 Bake in a nine-section oven (temperature settings: 100℃-110℃-120℃-140℃-160℃-160℃-160℃-160℃-160℃) at a speed of 25 yd / min.

[0077] Second coating: On the same coating line, the above-mentioned coating adhesive, with a viscosity adjusted to 300 Pa·s, is applied over the first coating, with a basis weight of 5 g / m². 2 Bake in a nine-section oven (temperature settings: 160℃-180℃-180℃-205℃-205℃-205℃-205℃-205℃) at a speed of 18 yd / min.

[0078] Performance Testing

[0079] Peel strength (ASTM D1876): 85 N / cm (demonstrates excellent adhesion to PET substrate).

[0080] Burning rate (FMVSS 302): 60 mm / min (meets flame retardant requirements).

[0081] Pressure retention rate (initial 70 kPa, after 12 s): >80% (far exceeds conventional requirements, excellent pressure retention performance).

[0082] Performance after thermal aging (150℃, 408h): Peel strength retention rate >92%, thanks to the thermal conductivity of boron nitride, the coating has excellent heat aging resistance.

[0083] Example 2: (Low dosage of bio-based thickener and reactive reinforcing filler)

[0084] <Coating Adhesive Preparation>

[0085] Component A was prepared under nitrogen protection by adding 100 parts of vinyl-terminated polydimethylsiloxane (viscosity 40,000 mPa·s), 5 parts of itaconic anhydride hydrogenated rosin adduct (acid value 130 mg KOH / g), 20 parts of vinyl-modified silica (particle size 50 nm, surface vinyl modification rate 0.8 mmol / g), and 0.01 parts of ethynylcyclohexanol to a planetary mixer and stirring under vacuum at 80 °C and -0.095 MPa for 1 hour. After cooling, component A was obtained.

[0086] Preparation of Component B: Hydrogen-containing silicone oil (Si-H to vinyl molar ratio of 1.0:1, viscosity 10 mPa·s) was mixed with an appropriate amount of methylsiloxane solvent to obtain Component B.

[0087] Preparation of coating adhesive solution: Take 100 parts of component A, add platinum catalyst (10 ppm based on Pt), mix well, then add component B, and adjust the viscosity to 15 Pa·s with solvent.

[0088] Coating Process

[0089] First coating: applied to PET OPW fabric, weight 55g / m². 2They are baked in an oven (temperature gradient 100-160℃) at a speed of 20 yd / min.

[0090] Second coating: coating weight 10g / m² 2 They were baked in an oven (temperature gradient 160-205℃) at a speed of 15 yd / min.

[0091] Performance Testing

[0092] Peel strength: 78 N / cm

[0093] Combustion rate: 65 mm / min

[0094] Pressure retention rate (70 kPa, 12 s): 83%

[0095] Peel strength retention rate after heat aging (150℃, 408h): 88%

[0096] Example 3: (High dosage of bio-based thickener and reactive reinforcing filler)

[0097] <Coating Adhesive Preparation>

[0098] Preparation of Component A: Under nitrogen protection, 100 parts of vinyl-terminated polydimethylsiloxane (viscosity 100,000 mPa·s), 25 parts of itaconic anhydride hydrogenated rosin adduct (acid value 180 mg KOH / g), 40 parts of vinyl-modified silicone resin powder (particle size 500 nm, surface vinyl modification rate 0.5 mmol / g), and 0.1 parts of ethynylcyclohexanol were added to a planetary mixer and stirred under vacuum at 100 °C and -0.095 MPa for 2 hours. After cooling, Component A was obtained.

[0099] Preparation of Component B: Hydrogen-containing silicone oil (Si-H to vinyl molar ratio of 1.5:1, viscosity 20 mPa·s) was mixed with an appropriate amount of methylsiloxane solvent to obtain Component B.

[0100] Preparation of coating adhesive solution: Take 100 parts of component A, add platinum catalyst (200 ppm Pt), mix well, then add component B, and adjust the viscosity to 12 Pa·s (first coating) and 350 Pa·s (second coating) with solvent.

[0101] Coating Process

[0102] First coating: 40g / m² (coating weight) 2 They are baked in an oven (temperature gradient 100-160℃) at a speed of 30 yd / min.

[0103] Second coating: 15g / m² 2 They were baked in an oven (temperature gradient 160-205℃) at a speed of 20 yd / min.

[0104] Performance Testing

[0105] Peel strength: 90 N / cm

[0106] Combustion rate: 55 mm / min

[0107] Pressure retention rate (70 kPa, 12 s): 85%

[0108] Peel strength retention rate after heat aging (150℃, 408h): 95%

[0109] Example 4: (Different reactive reinforcing fillers, boron nitride and silica mixture)

[0110] <Coating Adhesive Preparation>

[0111] Preparation of Component A: Under nitrogen protection, 100 parts of vinyl-terminated polydimethylsiloxane (viscosity 60,000 mPa·s), 15 parts of itaconic anhydride hydrogenated rosin adduct (acid value 160 mg KOH / g), 20 parts of vinyl-modified boron nitride nanosheets (particle size 100 nm, vinyl content 2 mmol / g), 10 parts of vinyl-modified silica (particle size 200 nm, surface vinyl modification rate 0.8 mmol / g), and 0.05 parts of ethynylcyclohexanol were added to a planetary mixer and stirred under vacuum at 95 °C and -0.095 MPa for 1.5 hours. After cooling, Component A was obtained.

[0112] Preparation of component B: Hydrogen-containing silicone oil (Si-H to vinyl molar ratio of 1.3:1, viscosity 15 mPa·s) was mixed with an appropriate amount of solvent to obtain component B.

[0113] Preparation of coating adhesive solution: Take 100 parts of component A, add platinum catalyst (100 ppm Pt), mix well, then add component B, and adjust the viscosity to 16 Pa·s (first coating) and 300 Pa·s (second coating) with solvent.

[0114] Coating Process

[0115] First coating: Adjust the viscosity of the above adhesive solution to 18 Pa·s with a solvent, and apply it to the PET OPW airbag fabric. The coating weight is 70 g / m². 2 Bake in a nine-section oven (temperature settings: 100℃-110℃-120℃-140℃-160℃-160℃-160℃-160℃-160℃) at a speed of 25 yd / min.

[0116] Second coating: On the same coating line, the above-mentioned coating adhesive, with a viscosity adjusted to 300 Pa·s, is applied over the first coating, with a basis weight of 15 g / m². 2Bake in a nine-section oven (temperature settings: 160℃-180℃-180℃-205℃-205℃-205℃-205℃-205℃) at a speed of 18 yd / min.

[0117] Performance Testing

[0118] Peel strength: 88 N / cm

[0119] Combustion rate: 58 mm / min

[0120] Pressure retention rate (70 kPa, 12 s): 82%

[0121] Peel strength retention rate after heat aging (150℃, 408h): 93%

[0122] Comparative Example 1: (using petroleum-based tackifiers and epoxy-functionalized siloxanes)

[0123] <Coating Adhesive Preparation>

[0124] Preparation of Component A: Under nitrogen protection, 100 parts of vinyl-terminated polydimethylsiloxane (viscosity 10,000 mPa·s), 20 parts of γ-glycidyl etheroxypropyltrimethoxysilane (replacing bio-based thickener), 30 parts of vinyl-modified boron nitride nanosheets (particle size 100 nm, vinyl content 0.05 mmol / g), and 0.05 parts of ethynylcyclohexanol were added to a planetary mixer and stirred at 90 °C and -0.095 MPa for 1.5 hours. After cooling, Component A was obtained.

[0125] Preparation of Component B: Hydrogen-containing silicone oil (viscosity 5 mPa·s) with a molar ratio of 1.2:1 to vinyl groups in Component A is mixed with an appropriate amount of methylsiloxane solvent to obtain Component B.

[0126] Preparation of coating adhesive solution: When using, take 100 parts of component A, add 1.5 parts of platinum catalyst (platinum content 50ppm), mix well, then add the corresponding amount of component B, and dilute with methylsiloxane solvent to adjust the viscosity.

[0127] Coating Process

[0128] First coating: Adjust the viscosity of the above adhesive solution to 18 Pa·s with a solvent, and apply it to the PET OPW airbag fabric. The coating weight is 40 g / m². 2 Bake in a nine-section oven (temperature settings: 100℃-110℃-120℃-140℃-160℃-160℃-160℃-160℃-160℃) at a speed of 25 yd / min.

[0129] Second coating: On the same coating line, the above-mentioned coating adhesive, with a viscosity adjusted to 300 Pa·s, is applied over the first coating, with a basis weight of 5 g / m². 2 Bake in a nine-section oven (temperature settings: 160℃-180℃-180℃-205℃-205℃-205℃-205℃-205℃) at a speed of 18 yd / min.

[0130] Performance Testing

[0131] Peel strength: 55 N / cm (significantly lower than Example 1)

[0132] Combustion rate: 62 mm / min

[0133] Pressure retention rate (70 kPa, 12 s): 70%

[0134] Peel strength retention rate after heat aging (150℃, 408h): 75%

[0135] It can be observed that petroleum-based tackifiers have insufficient adhesion to PET substrates, and their performance deteriorates significantly after thermal aging, proving that bio-based tackifiers are more suitable for PET in terms of structure and polarity.

[0136] Comparative Example 2: (Using untreated filler, ordinary silica)

[0137] <Coating Adhesive Preparation>

[0138] Preparation of Component A: Under nitrogen protection, 100 parts of vinyl-terminated polydimethylsiloxane (viscosity 10,000 mPa·s), 20 parts of itaconic anhydride hydrogenated rosin adduct (acid value 150 mg KOH / g), 30 parts of untreated boron nitride nanosheets (particle size 100 nm, without vinyl modification) and 0.05 parts of ethynylcyclohexanol were added to a planetary mixer and stirred at 90 °C and -0.095 MPa for 1.5 hours. After cooling, Component A was obtained.

[0139] Preparation of Component B: Hydrogen-containing silicone oil (viscosity 5 mPa·s) with a molar ratio of 1.2:1 to vinyl groups in Component A is mixed with an appropriate amount of methylsiloxane solvent to obtain Component B.

[0140] Preparation of coating adhesive solution: When using, take 100 parts of component A, add 1.5 parts of platinum catalyst (platinum content 50ppm), mix well, then add the corresponding amount of component B, and dilute with methylsiloxane solvent to adjust the viscosity.

[0141] Coating Process

[0142] First coating: Adjust the viscosity of the above adhesive solution to 18 Pa·s with a solvent, and apply it to the PET OPW airbag fabric. The coating weight is 40 g / m².2 Bake in a nine-section oven (temperature settings: 100℃-110℃-120℃-140℃-160℃-160℃-160℃-160℃-160℃) at a speed of 25 yd / min.

[0143] Second coating: On the same coating line, the above-mentioned coating adhesive, with a viscosity adjusted to 300 Pa·s, is applied over the first coating, with a basis weight of 15 g / m². 2 Bake in a nine-section oven (temperature settings: 160℃-180℃-180℃-205℃-205℃-205℃-205℃-205℃) at a speed of 18 yd / min.

[0144] Performance Testing

[0145] Peel strength: 50 N / cm

[0146] Burning rate: 70 mm / min (flame retardancy decreases)

[0147] Pressure retention rate (70 kPa, 12 s): 68%

[0148] Peel strength retention rate after heat aging (150℃, 408h): 80%

[0149] It can be seen that the untreated filler has poor dispersibility in the system and weak bonding with the organosilicon matrix, resulting in poor mechanical properties and air tightness. The reactive filler participates in crosslinking through surface vinyl groups, which enhances the overall network.

[0150] Comparative Example 3: (Using organic titanate instead of bio-based tackifier)

[0151] <Coating Adhesive Preparation>

[0152] Preparation of Component A: Under nitrogen protection, 100 parts of vinyl-terminated polydimethylsiloxane (viscosity 10,000 mPa·s), 20 parts of n-butyl titanate, 30 parts of vinyl-modified boron nitride nanosheets, and 0.05 parts of ethynylcyclohexanol were added to a planetary mixer and stirred at 90°C and -0.095 MPa for 1.5 hours. After cooling, Component A was obtained.

[0153] Preparation of Component B: Hydrogen-containing silicone oil with a molar ratio of 1.2:1 to vinyl groups in Component A is mixed with an appropriate amount of methylsiloxane solvent to obtain Component B.

[0154] Preparation of coating adhesive solution: When using, take 100 parts of component A, add 1.5 parts of platinum catalyst (platinum content 50ppm), mix well, then add the corresponding amount of component B, and dilute with methylsiloxane solvent to adjust the viscosity.

[0155] Coating Process

[0156] First coating: Adjust the viscosity of the above adhesive solution to 18 Pa·s with a solvent, and apply it to the PET OPW airbag fabric. The coating weight is 70 g / m². 2 Bake in a nine-section oven (temperature settings: 100℃-110℃-120℃-140℃-160℃-160℃-160℃-160℃-160℃) at a speed of 25 yd / min.

[0157] Second coating: On the same coating line, the above-mentioned coating adhesive, with a viscosity adjusted to 300 Pa·s, is applied over the first coating, with a basis weight of 5 g / m². 2 Bake in a nine-section oven (temperature settings: 160℃-180℃-180℃-205℃-205℃-205℃-205℃-205℃) at a speed of 18 yd / min.

[0158] Performance Testing

[0159] Peel strength: 42 N / cm

[0160] Combustion rate: 65 mm / min

[0161] Pressure retention rate (70 kPa, 12 s): 72%

[0162] Peel strength retention rate after heat aging (150℃, 408h): 68%

[0163] The table below summarizes the key performance data of the supplementary embodiments and comparative examples to visually demonstrate the superiority of the present invention.

[0164]

[0165]

[0166] The peel strength test method involves applying 0.5mm of adhesive onto PET, curing it, and then testing it. A peel strength test result greater than 80 N / cm is considered excellent, 71-80 N / cm is considered good, 51-70 N / cm is considered average, and a result below 50 N / cm is considered poor.

[0167] A comprehensive comparison shows that the examples demonstrate that the coating adhesive of the present invention maintains excellent adhesion, flame retardancy, pressure retention rate, and thermal stability under different dosages and types of bio-based tackifiers and reactive reinforcing fillers. In contrast, the performance of the comparative examples significantly decreased when petroleum-based tackifiers, untreated fillers, or traditional tackifiers were used, especially in terms of peel strength and retention rate after thermal aging.

Claims

1. A silicone coating adhesive suitable for OPW one-piece side curtain airbags, characterized in that, By weight, it comprises: 100 parts of vinyl-terminated polydimethylsiloxane; a hydrogen-containing silicone oil crosslinking agent; a platinum catalyst, 10-200 ppm (Pt); 5-25 parts of bio-based tackifier; 10-40 parts of reactive reinforcing filler; and 0.01-0.1 parts of inhibitor. The molar ratio of Si-H in the hydrogen-containing silicone oil crosslinking agent to vinyl in the vinyl-terminated polydimethylsiloxane is (1.0-1.5):

1. The bio-based tackifier is a bio-based itaconic anhydride graft-modified hydrogenated rosin resin. The reactive reinforcing filler is a micro / nano filler with vinyl groups on its surface after treatment.

2. The silicone coating adhesive according to claim 1, characterized in that, The bio-based thickener is synthesized from bio-based itaconic anhydride and hydrogenated rosin via a Diels-Alder reaction, with an acid value of 130-180 mg KOH / g.

3. The silicone coating adhesive according to claim 1, characterized in that, The reactive reinforcing filler is a micro / nano filler composed of one or more of silica, boron nitride, and silicone resin powder, with a particle size of 10-1000 nm, preferably 50-500 nm, and a surface vinyl modification rate of 0.5-2.0 mmol / g.

4. The silicone coating adhesive according to claim 1, characterized in that, The viscosity of the vinyl-terminated polydimethylsiloxane is 10,000-100,000 mPa·s, preferably 40,000-60,000 mPa·s.

5. The silicone coating adhesive according to claim 1, characterized in that, The hydrogen-containing silicone oil crosslinking agent contains at least 0.05 mol / 100g of silane and has a viscosity of 5-20 mPa·s.

6. The coating adhesive according to claim 1, characterized in that, The inhibitor used is one or more of ethynylcyclohexanol, dimethyl maleate, and methylbutynol, with ethynylcyclohexanol being preferred.

7. A method for preparing the organosilicon coating adhesive according to any one of claims 1-6, characterized in that, Includes the following steps: 1) Under inert gas protection, the vinyl-terminated polydimethylsiloxane, bio-based tackifier, reactive reinforcing filler and inhibitor are added to a planetary mixer and stirred under vacuum at 80-100°C for 1-2 hours to fully mix the components and remove moisture and air bubbles to obtain component A. 2) Mix the hydrogen-containing silicone oil crosslinking agent with a portion of the solvent and stir until homogeneous to obtain component B; 3) Before use, mix components A, B and catalyst in proportion and adjust to the required working viscosity with the remaining solvent.

8. The use of the silicone coating adhesive according to any one of claims 1-6 in the preparation of a PET-based OPW one-piece side curtain airbag.

9. The application according to claim 8, characterized in that, The preparation process includes: coating a first coating onto PET fabric with a basis weight of 40-70 g / m². 2 Baking at 160-200℃ for 1-3 minutes; applying a second coating on top of the first coating, with a basis weight of 5-15 g / m². 2 Bake at 160-200℃ for 1-3 minutes.

10. The application according to claim 9, characterized in that, In the PET-based OPW one-piece side curtain airbag, the coating weight is 45-85 g / m², based on PET fabric. 2 Pressure retention rate (70kPa, 12s) ≥80%, peel strength ≥80N / cm.

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