Flame-retardant light-shielding water-based polyurethane ultra-thin fabric for automobile sunroof and preparation method thereof

Abstract

The application belongs to the technical field of functional composite fabric, and particularly discloses a kind of water-based polyurethane super-thin fabric of flame-retardant light-shielding for automobile sunroof and a preparation method thereof.The water-based polyurethane super-thin fabric comprises a PET base cloth and a water-based polyurethane surface layer arranged on the base cloth.The PET base cloth is modified by polyether amine.The surface layer slurry used in the water-based polyurethane surface layer is composed of epoxy-modified water-based polyurethane emulsion, titanium dioxide / polyacrylate porous composite microspheres, melamine-modified nano-zinc oxide, water-based color paste, defoaming agent and thickening agent.The titanium dioxide / polyacrylate porous composite microspheres are prepared by continuous phase Pickering emulsion photopolymerization.Compared with the prior art, the water-based polyurethane fabric prepared by the application not only has thin thickness and light weight, but also has excellent flame-retardant performance and light-shielding performance, and has broad market prospects.

Description

Technical Field

[0001] This invention belongs to the field of functional composite fabric technology, and relates to the preparation of a light-blocking fabric, specifically to a flame-retardant light-blocking waterborne polyurethane ultrathin fabric for automotive sunroofs and its preparation method. Background Technology

[0002] Polyurethane synthetic leather boasts advantages such as a soft luster, supple feel, wear resistance, flexural strength, good cold resistance, and affordability, making it widely applicable in automotive interiors, footwear, and luggage. Car sunroofs effectively improve air circulation, increasing the intake of fresh air and quickly removing fog from the cabin on cloudy or rainy days. However, opening the sunroof exposes interior components to the outside environment, especially in strong sunlight. Direct sunlight entering the car can be glaring, causing interior aging and significantly increasing interior temperature. Sunroof sunshades are crucial components for blocking sunlight in cars. By using sunroof sunshades, direct sunlight and ultraviolet rays can be effectively reduced, lowering the interior temperature, providing a more comfortable driving and riding experience, and preventing wear and fading of seats, dashboards, and other interior components caused by direct sunlight.

[0003] However, existing automotive sunroof sunshade fabrics are relatively thick, and the use of light-blocking agents such as titanium dioxide and barium sulfate increases the fabric density. This causes the fabric to sag under its own weight during operation, making it prone to wrinkling or twisting when opened or closed, severely impacting its sun-shading effect and practicality. Especially with the development of the automotive industry and the increasing popularity of panoramic sunroofs, the area covered by sunshades has further increased, exacerbating the wrinkling or twisting problem. Furthermore, the flame-retardant effect of currently available sunshade fabrics, such as single-layer fabrics, composite fabrics, or suede-like fabrics, mainly relies on sprayed flame retardants. Over time, these flame retardants are lost, reducing the flame-retardant effect and compromising safety. Therefore, there is an urgent need to develop a flame-retardant, ultra-thin, light-blocking fabric for automotive sunroofs. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a flame-retardant and light-blocking waterborne polyurethane ultrathin fabric for automotive sunroofs and its preparation method. This invention uses waterborne polyurethane, which has advantages such as soft hand feel, wear resistance, flexibility, good cold resistance, and environmental friendliness, as the matrix material. It introduces titanium dioxide / polyacrylate porous composite microspheres as the main light-blocking agent, utilizing their porous characteristics to achieve excellent light-blocking effect and lightweighting. The PET base fabric is subjected to plasma hydrophilic treatment to increase the number of carboxyl functional groups on the surface of the base fabric, and then impregnated with grafted polyetheramine to enhance the peel strength between the base fabric and the waterborne polyurethane layer. Furthermore, melamine-modified nano-zinc oxide is used to achieve both flame-retardant properties and enhanced light-blocking effect, effectively solving the problems in the prior art.

[0005] This invention is achieved through the following technical solution: A flame-retardant and light-shielding waterborne polyurethane ultrathin fabric for automotive sunroofs includes a PET base fabric and a waterborne polyurethane surface layer disposed on the base fabric. The PET base fabric is modified with polyetheramine. The surface layer slurry of the waterborne polyurethane surface layer is composed of epoxy-modified waterborne polyurethane emulsion, titanium dioxide / polyacrylate porous composite microspheres, melamine-modified nano zinc oxide, waterborne color paste, defoamer, and thickener. The titanium dioxide / polyacrylate porous composite microspheres are prepared by continuous phase Pickering emulsion photopolymerization.

[0006] A further improvement to the present invention is as follows: The water-based polyurethane topcoat slurry is composed of the following raw materials in parts by weight: 100 parts of epoxy-modified waterborne polyurethane emulsion; 5-20 parts of titanium dioxide / polyacrylate porous composite microspheres; 3-12 parts of melamine-modified nano zinc oxide; 0.5-1 parts of water-based pigment; 2-4 parts of defoamer; Thickener 0.5-1 parts.

[0007] Furthermore, the polyetheramine modification process is as follows: the base fabric is treated by a wide-width plasma cleaner at a speed of 50-100 mm / s, then impregnated with a certain concentration of polyetheramine D-230 aqueous solution, squeezed dry, and ironed flat to obtain polyetheramine modified PET base fabric.

[0008] Furthermore, the concentration of the polyetheramine D-230 aqueous solution is 0.5-2 wt%; the oxygen concentration of the plasma cleaner is 20-40 SCCM, and the power is 300-600 W.

[0009] Furthermore, the titanium dioxide / polyacrylate porous composite microspheres are prepared by the following steps: nano-titanium dioxide is uniformly dispersed in deionized water, and methyl methacrylate, N,N-diethylaminomethyl methacrylate monomer, ethylene glycol dimethacrylate crosslinking agent, I819 photoinitiator, and xylene porogen are added. After the addition is complete, the mixture is emulsified at high speed to obtain an O / W type Pickering emulsion. The prepared Pickering emulsion is introduced into a quartz microchannel photoreactor through a peristaltic pump, and photopolymerization reaction is carried out under ultraviolet LED irradiation. The resulting suspension is filtered, and the filtrate is washed with ethanol to remove unreacted organic matter and by-products. The filtrate is then vacuum dried to obtain titanium dioxide / polyacrylate porous composite microspheres.

[0010] Furthermore, the ratio of the amounts of nano-titanium dioxide, methyl methacrylate, N,N-diethylaminomethyl methacrylate monomer, ethylene glycol dimethacrylate crosslinking agent, I819 photoinitiator, xylene porogen, and deionized water is 3-8 g: 10-15 g: 10-15 g: 2-6 g: 1-1.5 g: 50-80 mL: 200 mL.

[0011] Furthermore, the high-speed pulping speed is 10-15 krpm; the flow rate of the peristaltic pump is 15-50 mL / h; Furthermore, the quartz microchannel photoreactor has a capacity of 10 mL and an inner diameter of 1000 µm, and the ultraviolet LED lamp has a wavelength of 365 nm; the vacuum drying temperature is 50-80 ℃ and the time is 20-30 h.

[0012] Furthermore, the melamine-modified nano zinc oxide is prepared by the following steps: dispersing nano zinc oxide in an oxalic acid aqueous solution, stirring at room temperature for 1-3 hours, centrifuging, washing with deionized water, drying, grinding, and then adding it to an ethanol solution containing melamine, followed by the addition of N,N'-dicyclohexylcarbodiimide, stirring for 1-3 hours, centrifuging, washing with ethanol, drying, and grinding to obtain melamine-modified nano zinc oxide.

[0013] Furthermore, the concentration of the oxalic acid aqueous solution is 0.1-0.3 mol / L, and the ratio of the amount of nano zinc oxide to the oxalic acid aqueous solution is 1 g: 5-15 mL; And / or, the ratio of the nano zinc oxide, melamine, N,N'-dicyclohexylcarbodiimide and ethanol is 20-30 g: 0.5-1.5 g: 0.5-1.5 g: 500 mL.

[0014] A further improvement to the present invention is as follows: A method for preparing a flame-retardant and light-blocking waterborne polyurethane ultrathin fabric for automotive sunroofs includes the following steps: S1. Mix epoxy-modified waterborne polyurethane emulsion, waterborne color paste and defoamer, stir for 10-30 min, add titanium dioxide / polyacrylate porous composite microspheres, continue stirring for 10-30 min, add melamine-modified nano zinc oxide and thickener, stir for 3-5 min to obtain waterborne polyurethane surface slurry. S2. Apply the water-based surface layer slurry onto the release paper using a two-roll calender, dry it at 100-150℃, and at a speed of 6-8 m / min to obtain a surface layer semi-finished product. S3. After the base fabric is treated by a wide-width plasma cleaner at a speed of 50-100 mm / s, it is impregnated with a polyetheramine D-230 aqueous solution. Then, the moisture in the base fabric is squeezed out by a squeeze roller, ironed, and then hot-pressed and cured with the surface layer semi-finished product described in step S2 through a two-roll calender. It is then dried at 120-150 ℃ for 3-8 min, cooled, and the release paper is separated to obtain a flame-retardant and light-blocking waterborne polyurethane ultra-thin fabric for automotive sunroofs.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: I. This invention uses waterborne polyurethane, which boasts advantages such as soft hand feel, wear resistance, flexibility, cold resistance, and environmental friendliness, as the matrix material. It introduces porous titanium dioxide / polyacrylate composite microspheres prepared by continuous-phase Pickering emulsion photopolymerization as the main light-blocking agent, and further synergistically modifies nano-zinc oxide light-blocking agents to achieve excellent light-blocking effects and lightweighting. During the Pickering emulsion formation process, titanium dioxide powder acts as a solid emulsifier at the oil-water interface, forming a stable O / W type emulsion. Further in-situ photopolymerization involves phase separation of polyacrylate and xylene solvent during polymerization. After removing xylene, porous composite microspheres with titanium dioxide powder coated on the surface are formed, effectively improving light-blocking performance while reducing material density, thus contributing to the lightweighting of light-blocking waterborne polyurethane fabrics.

[0016] II. In this invention, the PET base fabric is first subjected to plasma hydrophilic treatment to increase the number of carboxyl functional groups on the surface of the base fabric, and then impregnated with a polyetheramine solution. Through the chemical reaction of -COOH and -NH2, polyetheramine is grafted onto the base fabric. Furthermore, the -NH2 groups in the polyetheramine react with the epoxy groups in the surface slurry to enhance the peel strength between the base fabric and the waterborne polyurethane layer.

[0017] Third, this invention uses inexpensive and flame-retardant melamine, which is grafted onto the surface of nano zinc oxide through a chemical reaction. This not only improves the dispersion performance of nano zinc oxide, but also enhances the light-blocking effect of the fabric while giving it flame-retardant properties. Attached Figure Description

[0018] Figure 1 SEM image of the titanium dioxide / polyacrylate porous composite microspheres prepared in Example 1; Figure 2 The image shows the pore size distribution curve of the titanium dioxide / polyacrylate porous composite microspheres prepared in Example 1. Detailed Implementation

[0019] The present invention will now be described in detail with reference to specific embodiments.

[0020] The raw materials used in this invention, such as nano-titanium dioxide powder, nano-zinc oxide powder, methyl methacrylate, N,N-diethylaminomethyl methacrylate, ethylene glycol dimethacrylate, melamine, polyetheramine, defoamer, thickener, water-based color paste, and xylene, are all commercially available. Technical personnel can select them as needed. The sources of some raw materials are described in the following specific embodiments: The epoxy resin-modified waterborne polyurethane emulsion is the S6680D product of Huai'an Kaiyue Technology Development Co., Ltd. The defoamer is BYK094 from BYK GmbH, Germany. The thickener is TAFIGEL® PUR 85 from the German company Minling.

[0021] Example 1 (1) Preparation of porous titanium dioxide / polyacrylate composite microspheres 5 g of nano-titanium dioxide and 200 mL of deionized water were added to a single-necked brown bottle. After ultrasonic dispersion for 5 min, the nano-titanium dioxide was uniformly dispersed in the aqueous phase in a suspended state. Then, 12 g of methyl methacrylate, 12 g of N,N-diethylaminomethyl methacrylate monomer, 4 g of ethylene glycol dimethacrylate crosslinking agent, 1.2 g of I819 photoinitiator, and 70 mL of xylene porogen were added. The mixture was then emulsified at a high speed of 12 krpm for 5 min to obtain an O / W type Pickering emulsion. The prepared Pickering emulsion was introduced into a quartz photomicrochannel reactor (10 mL, inner diameter 1000 µm) at a flow rate of 20 mL / h using a peristaltic pump and irradiated under a 365 nm ultraviolet LED lamp. The resulting suspension was filtered, and the filtrate was washed with ethanol to remove unreacted organic matter and by-products. The filtrate was then vacuum dried at 60 °C for 24 h to obtain titanium dioxide / polyacrylate porous composite microspheres.

[0022] Figure 1 SEM image of the prepared titanium dioxide / polyacrylate porous composite microspheres; Figure 2 The diagram shows the pore size distribution of the prepared titanium dioxide / polyacrylate porous composite microspheres.

[0023] (2) Melamine modification of nano zinc oxide 25 g of nano zinc oxide was dispersed in 250 mL of 0.2 mol / L oxalic acid aqueous solution by high-speed stirring. After stirring at room temperature for 2 hours, the solution was centrifuged, washed with deionized water, dried, and ground. Then, it was added to 500 mL of ethanol solution containing 1 g of melamine. 0.1 g of N,N'-dicyclohexylcarbodiimide was added, and the solution was stirred for 2 hours. After centrifugation, washing with ethanol, drying, and grinding, melamine-modified nano zinc oxide was obtained.

[0024] (3) Preparation of slurry for waterborne polyurethane surface layer By weight, 100 parts of epoxy-modified waterborne polyurethane emulsion, 1 part of waterborne color paste and 2 parts of defoamer are mixed and stirred for 20 minutes. Then, 14 parts of titanium dioxide / polyacrylate porous composite microspheres are added and stirred for another 20 minutes. Finally, 8 parts of melamine-modified nano zinc oxide and 0.5 parts of thickener are added and stirred for 5 minutes to obtain waterborne surface slurry. (4) Production of flame-retardant and light-shielding waterborne polyurethane ultrathin fabric S1. Mix epoxy-modified waterborne polyurethane emulsion, waterborne color paste and defoamer, stir for 20 min, add titanium dioxide / polyacrylate porous composite microspheres, continue stirring for 20 min, add melamine-modified nano zinc oxide and thickener, stir for 3-5 min to obtain waterborne polyurethane surface layer slurry. S2. Apply the water-based surface layer slurry onto the release paper using a two-roll calender, dry it at 120 ℃, and at a speed of 6-8 m / min to obtain a surface layer semi-finished product. S3. After the base fabric is treated by a wide-width plasma cleaner (oxygen 40 SCCM, power 400W) at a speed of 80 mm / s, it is impregnated with a 1.2 wt% polyetheramine D-230 aqueous solution. Then, the moisture in the base fabric is squeezed out by the extrusion roller, ironed, and then hot-pressed and cured with the surface layer semi-finished product described in S2 through a two-roll calender. After drying at 130 ℃ for 5 min, the release paper is separated after cooling to obtain the flame-retardant and light-blocking waterborne polyurethane ultra-thin fabric for automotive sunroofs.

[0025] Example 2 In this embodiment, the amount of titanium dioxide / polyacrylate porous composite microspheres added is 6 parts. Other operations are roughly the same as in Example 1, and will not be repeated here.

[0026] Example 3 In this embodiment, compared with Example 1, the amount of melamine-modified nano zinc oxide added is 4 parts, and other operations are roughly the same as in Example 1, which will not be repeated here.

[0027] Comparative Example In this comparative example, the base fabric was not modified with polyetheramine, and other operations were largely the same as in Example 1, so they will not be repeated here.

[0028] Test case The flame-retardant and light-blocking waterborne polyurethane ultrathin fabrics for automotive sunroofs prepared in Examples 1 to 4 and the comparative example were tested for light-blocking rate, lightfastness to sunlight, flame retardant properties, and folding fastness, respectively. The methods used are as follows: Opacity: Tested according to GB / T 42999-2023.

[0029] Flame retardant performance: Tested according to GB / T 8410-2006.

[0030] Peel strength: Tested according to GB / T 8949-2008.

[0031] Flexural strength: Tested according to the provisions of QB / T 2714-2018.

[0032] The test results are shown in the table below: Case test items Opacity (%) Flame retardant properties Peel strength (N / 3cm) Flexural strength (10,000 cycles, 23°C) Example 1 100 B 68 7.6 Example 2 76.8 B 84 9.1 Example 3 99.2 C 75 8.2 Comparative Example 100 D 44 7.3 As shown in the table above, this invention introduces titanium dioxide / polyacrylate porous composite microspheres and melamine-modified nano-zinc oxide into the waterborne polyurethane surface layer for synergistic light-blocking. Furthermore, the melamine-modified nano-zinc oxide can also serve as a flame retardant. By utilizing polyetheramine-modified base fabric in conjunction with epoxy-modified waterborne polyurethane surface layer slurry, the light-blocking and flame-retardant properties of the waterborne polyurethane ultrathin fabric are ensured, while enhancing folding strength and peel strength, and reducing thickness (no adhesive layer required).

[0033] The above description of the embodiments is only for illustrating the technical concept and features of the present invention. Its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. Those skilled in the art can obviously easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative effort. Therefore, the above embodiments should not be used to limit the scope of protection of the present invention. All improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A flame-retardant, light-blocking, water-based polyurethane ultrathin fabric for automotive sunroofs, characterized in that: The product includes a PET base fabric and a waterborne polyurethane surface layer disposed on the base fabric. The PET base fabric is modified with polyetheramine. The surface layer slurry used in the waterborne polyurethane surface layer is composed of an epoxy-modified waterborne polyurethane emulsion, titanium dioxide / polyacrylate porous composite microspheres, melamine-modified nano zinc oxide, waterborne color paste, defoamer, and thickener. The titanium dioxide / polyacrylate porous composite microspheres are prepared by continuous phase Pickering emulsion photopolymerization.

2. The flame-retardant and light-blocking waterborne polyurethane ultrathin fabric for automotive sunroofs according to claim 1, characterized in that: The water-based polyurethane topcoat slurry is composed of the following raw materials in parts by weight: 100 parts of epoxy-modified waterborne polyurethane emulsion; 5-20 parts of titanium dioxide / polyacrylate porous composite microspheres; 3-12 parts of melamine-modified nano zinc oxide; 0.5-1 parts of water-based pigment; 2-4 parts of defoamer; Thickener 0.5-1 parts.

3. The flame-retardant and light-blocking waterborne polyurethane ultrathin fabric for automotive sunroofs according to claim 1, characterized in that: The polyetheramine modification process is as follows: the base fabric is treated by a wide-width plasma cleaner at a speed of 50-100 mm / s, then impregnated with a certain concentration of polyetheramine D-230 aqueous solution, squeezed dry, and ironed flat to obtain polyetheramine modified PET base fabric.

4. The flame-retardant and light-blocking waterborne polyurethane ultrathin fabric for automotive sunroofs according to claim 3, characterized in that: The concentration of the polyetheramine D-230 aqueous solution is 0.5-2 wt%; the oxygen concentration of the plasma cleaner is 20-40 SCCM, and the power is 300-600 W.

5. The flame-retardant and light-shielding waterborne polyurethane ultrathin fabric for automotive sunroofs according to claim 1, characterized in that: The titanium dioxide / polyacrylate porous composite microspheres were prepared by the following steps: nano-titanium dioxide was uniformly dispersed in deionized water, and methyl methacrylate, N,N-diethylaminomethyl methacrylate monomer, ethylene glycol dimethacrylate crosslinking agent, I819 photoinitiator, and xylene porogen were added. After the addition was completed, the mixture was emulsified at high speed to obtain an O / W type Pickering emulsion. The prepared Pickering emulsion was introduced into a quartz photomicrochannel reactor through a peristaltic pump and photopolymerization was carried out under ultraviolet LED irradiation. The resulting suspension was filtered, and the filtrate was washed with ethanol to remove unreacted organic matter and by-products. The filtrate was then vacuum dried to obtain titanium dioxide / polyacrylate porous composite microspheres.

6. The flame-retardant and light-blocking waterborne polyurethane ultrathin fabric for automotive sunroofs according to claim 5, characterized in that: The ratio of nano-titanium dioxide, methyl methacrylate, N,N-diethylaminomethyl methacrylate monomer, ethylene glycol dimethacrylate crosslinking agent, I819 photoinitiator, xylene porogen, and deionized water is 3-8 g: 10-15 g: 10-15 g: 2-6 g: 1-1.5 g: 50-80 mL: 200 mL.

7. The flame-retardant and light-shielding waterborne polyurethane ultrathin fabric for automotive sunroofs according to claim 5, characterized in that: The high-speed pulping speed is 10-15 krpm; the flow rate of the peristaltic pump is 15-50 mL / h; the capacity of the quartz microchannel photoreactor is 10 mL and the inner diameter is 1000 µm; the wavelength of the ultraviolet LED lamp is 365 nm; the vacuum drying temperature is 50-80℃ and the time is 20-30 h.

8. The flame-retardant and light-blocking waterborne polyurethane ultrathin fabric for automotive sunroofs according to claim 1, characterized in that: The melamine-modified nano zinc oxide is prepared by the following steps: dispersing nano zinc oxide in an aqueous oxalic acid solution, stirring at room temperature for 1-3 hours, centrifuging, washing with deionized water, drying, grinding, and then adding it to an ethanol solution containing melamine, followed by the addition of N,N'-dicyclohexylcarbodiimide, stirring for 1-3 hours, centrifuging, washing with ethanol, drying, and grinding to obtain melamine-modified nano zinc oxide.

9. The flame-retardant and light-blocking waterborne polyurethane ultrathin fabric for automotive sunroofs according to claim 8, characterized in that: The concentration of the oxalic acid aqueous solution is 0.1-0.3 mol / L, and the ratio of the amount of nano zinc oxide to the oxalic acid aqueous solution is 1g:5-15mL; And / or, the ratio of the nano zinc oxide, melamine, N,N'-dicyclohexylcarbodiimide and ethanol is 20-30 g: 0.5-1.5 g: 0.5-1.5 g: 500 mL.

10. The method for preparing the flame-retardant and light-blocking waterborne polyurethane ultrathin fabric for automotive sunroofs as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Mix epoxy-modified waterborne polyurethane emulsion, waterborne color paste and defoamer, stir for 10-30 min, add titanium dioxide / polyacrylate porous composite microspheres, continue stirring for 10-30 min, add melamine-modified nano zinc oxide and thickener, stir for 3-5 min to obtain waterborne polyurethane surface slurry. S2. Apply the water-based surface layer slurry onto the release paper using a two-roll calender, dry it at 100-150℃, and at a speed of 6-8m / min to obtain a surface layer semi-finished product. S3. After the base fabric is treated by a wide-width plasma cleaner at a speed of 50-100 mm / s, it is impregnated with a polyetheramine D-230 aqueous solution. Then, the moisture in the base fabric is squeezed out by the extrusion roller, ironed, and then hot-pressed and cured with the surface layer semi-finished product described in step S2 through a two-roll calender. It is then dried at 120-150℃ for 3-8 minutes, cooled, and the release paper is separated to obtain the flame-retardant and light-blocking waterborne polyurethane ultra-thin fabric for automotive sunroofs.

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