A silicone coating, a TPU-based projection screen containing a silicone coating, and a method for preparing the screen.

Abstract

This invention discloses a silicone coating, a TPU-based projection screen containing the silicone coating, and a preparation method thereof. The silicone coating is prepared from the following raw materials in parts by weight: 1-5 parts polydimethylsiloxane, 1-5 parts polyether-modified polydimethylsiloxane, 0.5-4 parts octamethylcyclotetrasiloxane, 0.5-3.5 parts triethoxysilane, 0.1-0.2 parts white spirit, 0.1-0.2 parts decadecane, 0.5-1 parts platinum vulcanizing agent, 0.8-2.5 parts reinforcing material, 0.01-0.03 parts tackifier, 0.01-0.03 parts antistatic agent, 0.5-2 parts fluff powder, 0.05-0.1 parts matting powder, and 0.01-0.03 parts dispersant. The silicone coating provided by this invention has good wear resistance and weather resistance. The TPU-based projection screen material obtained has excellent weather resistance, wear resistance, environmental friendliness and non-toxicity, anti-aging, UV resistance and easy cleaning properties.

Description

Technical Field

[0001] This invention belongs to the field of new material preparation technology, specifically relating to a silicone coating, a TPU-based projection screen containing a silicone coating, and a preparation method thereof. Background Technology

[0002] Silicone coating is a functional coating material, originally used to manufacture waterproof and antifouling coatings. With the development of materials science, silicone coating has gradually been applied to a wider range of fields, such as electronics, automobiles, and construction. The main component of silicone coating is organosilicon resin, such as polydimethylsiloxane, and fillers and functional additives are usually added according to the application requirements to meet different usage scenarios.

[0003] A projection screen is a special screen device used to receive projected images, mainly used in conference rooms, classrooms, home theaters, and other similar settings. Existing technologies have numerous reports on projection screens. For example, Chinese patent document CN107841240A discloses a coating material for projection screens and its preparation method. The material composition by weight is: 80-100 parts silicone resin, 20-30 parts titanium dioxide, 5-10 parts silica powder, 2-5 parts aluminum oxide, 0.2-0.5 parts sodium oxide, 5-15 parts magnesium silicate, 1-2 parts magnesium oxide, 1.25-2.5 parts curing agent, 0.25-1 part defoamer, and 0.75-1.25 parts leveling agent. The ink for projection screens prepared using the above method exhibits excellent thermal stability and good adhesion, but its abrasion resistance and weather resistance need further improvement. Furthermore, the use of numerous particles such as titanium dioxide, silica powder, and aluminum oxide results in poor compatibility with silicone resin, hindering dispersion. For example, Chinese patent document CN118444519A provides a projection screen and its manufacturing method. It employs pre-set light-absorbing and reflective particles. The light-absorbing particles are located on the side away from the substrate layer and concentrated on one surface of the grating prism structure layer; or, the light-absorbing particles are located on the side away from the substrate layer and concentrated on the opposite surface of the grating prism structure layer. This allows the projection screen to simultaneously possess light-absorbing and reflective functions, achieving the goal of light absorption and reflectivity on the upper and lower sides of the grating prism structure layer, respectively. However, the above technical solution only fully considers the poor visual effect and cost of the projection screen, without considering improvements to other performance aspects such as weather resistance.

[0004] Therefore, in view of the shortcomings of the prior art, the present invention is proposed. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a silicone coating, a TPU-based projection screen containing a silicone coating, and a preparation method thereof. The silicone coating has good wear resistance and weather resistance, and the resulting TPU-based projection screen material has excellent weather resistance, wear resistance, environmental friendliness and non-toxicity, anti-aging, UV resistance, and easy cleaning properties.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a silicone coating prepared from the following raw materials in parts by weight: 1-5 parts polydimethylsiloxane, 1-5 parts polyether-modified polydimethylsiloxane, 0.5-4 parts octamethylcyclotetrasiloxane, 0.5-3.5 parts triethoxysilane, 0.1-0.2 parts white spirit, 0.1-0.2 parts decadecane, 0.5-1 parts platinum vulcanizing agent, 0.8-2.5 parts reinforcing material, 0.01-0.03 parts tackifier, 0.01-0.03 parts antistatic agent, 0.5-2 parts fluffing powder, 0.05-0.1 parts matting powder, and 0.01-0.03 parts dispersant.

[0008] Preferably, the preparation of the reinforcing material includes the following steps:

[0009] (1) Modification of attapulgite: attapulgite is mixed with sodium hydroxide and subjected to high temperature treatment. After the treatment is completed, it is crushed to obtain pre-modified attapulgite.

[0010] (2) Preparation of chitosan acetic acid solution: Add chitosan to acetic acid solution, stir and disperse evenly, and set aside;

[0011] (3) Chitosan composite: The pre-modified attapulgite obtained in step (1) is added to the chitosan acetic acid solution obtained in step (2), stirred and dried, then ground and sieved to obtain modified attapulgite;

[0012] (4) Modification of silica: Add silica to N,N-dimethylformamide, stir and disperse evenly, then add succinic anhydride and KH550, and then react under stirring and heating conditions. Then centrifuge, and then wash and dry to obtain modified silica.

[0013] (5) The modified attapulgite obtained in step (3) and the modified silica obtained in step (4) are added to water in sequence, stirred, centrifuged, washed and dried to obtain the reinforcing material.

[0014] More preferably, in step (1), the mass ratio of attapulgite to sodium hydroxide is 1:0.4 to 0.65, the high-temperature treatment temperature is 780 to 805°C, and the treatment time is 0.5 to 4 hours.

[0015] More preferably, in step (2), the concentration of the acetic acid solution is 0.5–1.2 wt%, and the concentration of chitosan is 1.2–2.5 wt%.

[0016] More preferably, in step (3), the mass ratio of pre-modified attapulgite to chitosan is 8-12:1; the stirring temperature is room temperature, the processing time is 24-72h; the drying temperature is 105-110℃, and the sieve mesh is 100-150 mesh.

[0017] In step (4), the heating temperature is 30-40℃ and the heating time is 0.5-6h; the mass ratio of silica, N,N-dimethylformamide, succinic anhydride and KH550 is 1:40-75:2.5-5.5:3.5-6.5.

[0018] In step (5), the mass ratio of modified attapulgite, modified silica, and water is 1-2:0.5-1:10; the stirring temperature is 30-40℃, and the treatment time is 0.5-4h.

[0019] Secondly, the present invention provides the application of the above-mentioned silicone coating in the preparation of TPU-based projection screens.

[0020] Thirdly, the present invention provides a method for preparing a TPU-based material for projection screens, comprising the following steps:

[0021] S1. Apply silicone adhesive evenly to one side of the TPU substrate, then cure and cool to obtain the base coating.

[0022] S2. Weigh the raw materials of the silicone coating according to any one of claims 1 to 5 in proportion, mix and disperse evenly, then coat it onto release paper, treat it at 75 to 85°C to reach a semi-vulcanized state, and then cover it onto the base coating; subsequently, perform pressure setting and baking treatment to achieve complete vulcanization, and finally separate the release paper to obtain the silicone coating.

[0023] S3. Apply the mixed solvent to the adhesive coating and bake it.

[0024] S4. Repeat steps S1 to S3 on the other side of the TPU substrate. After the process is completed, the TPU base material is obtained.

[0025] Preferably, in step S1, the preparation of the silicone adhesive includes the following steps:

[0026] The hydrogen-containing polysiloxane, vinyl polysiloxane, dimethyl dichlorosilane, octamethylcyclotetrasiloxane, and platinum catalyst are mixed evenly in weight proportions of 2-7 parts, 1-5 parts, 1-4 parts, 0.5-1.5 parts, and 0.02-0.05 parts, respectively, and then mixed with 4-8 parts of white spirit to obtain the final product.

[0027] The coating amount of silicone adhesive is 20-30 g / m². 2 The curing temperature is 115-125℃, and the curing time is 1-5 minutes.

[0028] Preferably, in step S2, the coating amount on the release paper is 200-300 g / m². 2 The treatment time is 1 to 5 minutes at 75 to 85°C; the baking temperature is 125 to 135°C and the baking time is 1 to 5 minutes.

[0029] Preferably, in step S3, the mixed solvent is obtained by mixing the following raw materials in the following mass fractions: 45-55% dimethylpolysiloxane, 5-15% silica, 25-35% decadecane, and 3-10% dimethyl silicone oil;

[0030] The coating amount is 20-30 g / m² 2 The baking temperature is 125-130℃, and the baking time is 1-5 minutes.

[0031] Of course, the present invention also aims to protect the TPU-based material for projection screens prepared by the method.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention provides a TPU-based material that can be used to make projection screens. The TPU-based material has excellent weather resistance, wear resistance, environmental friendliness and non-toxicity, anti-aging, UV resistance and easy cleaning properties, and has excellent overall performance.

[0034] The preparation method of TPU-based material provided by this invention has the same double-sided treatment, which consists of a base coating, a silicone coating, and a surface treatment. The base coating is an adhesive applied to the TPU base material, which is beneficial to the adhesion of the silicone coating. The silicone coating, as the main material layer, gives the material excellent comprehensive properties. The surface treatment provides the TPU base material with good smoothness, dust resistance, wear resistance, and adhesion.

[0035] In this invention, the adhesive component used in the primer, after being baked and cured at 120°C, can withstand boiling in water at 100°C for one hour without delamination, and has a very good bonding effect.

[0036] In this invention, the silicone coating possesses excellent weather resistance, wear resistance, and is non-toxic and odorless. Furthermore, the added matting powder, antistatic agent, and other additives endow the silicone coating with superior antistatic and matting properties, meeting the requirements for projection screen applications. The reinforcing material further enhances the weather resistance and wear resistance of the silicone coating. Specifically, the reinforcing material uses palladium, chitosan, and silica as its main components. Silica itself is an excellent filler particle, effectively improving the corrosion resistance, wear resistance, tensile and compressive strength of the silicone coating. However, it is prone to agglomeration, and large quantities can lead to problems. The coating system suffers from a tendency to thicken, hence the use of palladium in this invention. This reduces the cost of the reinforcing material and, when used in conjunction with silica, provides complementary advantages and maximizes synergistic effects. However, palladium, as a filler, exhibits poor compatibility and dispersibility with resins. Therefore, this invention incorporates chitosan, rich in hydroxyl and carboxyl groups, for modification to improve its compatibility with resins. Another purpose of introducing chitosan is to facilitate the use of silica, allowing it to synergistically enhance the performance of the silicone coating. The reinforcing material provided in this invention, during use, involves carboxylation of silica, which increases its surface polarity and improves its compatibility with resins. Simultaneously, the introduced carboxyl groups and some of the hydroxyl groups present in the silica can bond with the chitosan-infused palladium through hydrogen bonds and weak interactions, helping to form a large network system that densely fills the spaces between resins, improving the film density of the silicone coating and thus enhancing its overall performance. Furthermore, the attapulgite in this invention undergoes high-temperature treatment, which enhances its activity and improves its binding with chitosan. In summary, the attapulgite and silica provided by this invention, based on the use of chitosan as an organic compound, maximize the improvement of the performance of the silicone coating by the reinforcing material. Attached Figure Description

[0037] Figure 1 This is a picture of the product obtained in Example 4. Detailed Implementation

[0038] The embodiments of the present invention are described in detail below. All embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0039] Unless otherwise specified, all chemical reagents and production equipment involved in this invention are purchased from the market.

[0040] Among them, silicone adhesives include:

[0041] The hydrogen-containing polysiloxane, brand name SH202, was purchased from Hubei Longsheng Sihai New Materials Co., Ltd., and has a hydrogen content of approximately 1.2%.

[0042] Vinyl polysiloxane, brand name DY-V401-5000, vinyl content 0.004mol / 100g, purchased from Shandong Dayi Chemical Co., Ltd.

[0043] The platinum catalyst was a 3% isopropanol chloroplatinic acid solution, purchased from Dongguan Tianan Silica Gel Co., Ltd.

[0044] Among them, the silicone coating includes:

[0045] Polydimethylsiloxane, brand name SH-D3, was purchased from Hubei Longsheng Sihai New Materials Co., Ltd.

[0046] The polyether-modified polydimethylsiloxane, brand name SH204, was purchased from Hubei Longsheng Sihai New Materials Co., Ltd.

[0047] Platinum curing agent, brand name TNA-25PS, purchased from Dongguan Tianan Silicone Co., Ltd.

[0048] Tackifier, terpene-styrene resin, brand name KH-792, purchased from Dongguan Dinghai Plastics & Chemical Co., Ltd.

[0049] The antistatic agent, made from chloride, silicone oil, polyvinyl alcohol and vinyl chloride, is branded K-595 and purchased from Hangzhou Lin'an Dechang Static Electricity Technology Co., Ltd.

[0050] The fluff powder, made from acrylic acid and polyurethane, was purchased from Shenzhen Xingsheng Zhuguang Chemical Pigment Co., Ltd.

[0051] Matting powder, made from silicon dioxide, silicate and talc, was purchased from Shenzhen Xingsheng Pearl Chemical Pigment Co., Ltd.

[0052] The dispersant was casein, purchased from Guangdong Zhongtai Lianhua New Materials Co., Ltd.

[0053] Among them, in the mixed solvent:

[0054] Dimethylpolysiloxane, brand name WS-1115, was purchased from Jiangxi Wuseshi New Materials Co., Ltd.

[0055] Dimethyl silicone oil with a viscosity of approximately 5000 mPa·s (25℃) was purchased from Hubei Longsheng Sihai New Materials Co., Ltd.

[0056] The silica was purchased from Aladdin Technology Co., Ltd., with a particle size of approximately 50 nm.

[0057] The retto stone was purchased from Hubei Mingliu Retto Stone Technology Co., Ltd.

[0058] The degree of deacetylation of the chitosan was approximately 85%, and it was purchased from Shandong Yatu Biotechnology Co., Ltd.

[0059] The TPU material is purchased from the market. This invention does not specifically limit its source or size, but only to the extent that it can be implemented by those skilled in the art.

[0060] Example 1

[0061] A silicone coating is prepared from the following raw materials by weight: 5g polydimethylsiloxane, 3g polyether-modified polydimethylsiloxane, 3g octamethylcyclotetrasiloxane, 2g triethoxysilane, 0.15g white spirit, 0.15g decadecane, 0.75g platinum curing agent, 2.2g reinforcing agent, 0.02g tackifier, 0.02g antistatic agent, 0.1g fluff powder, 0.08g matting agent, and 0.02g dispersant.

[0062] The preparation of the reinforcing material includes the following steps:

[0063] (1) Modification of attapulgite: attapulgite and sodium hydroxide were mixed at a mass ratio of 1:0.5 and then subjected to high temperature treatment (795℃, 1h). After the treatment was completed, the mixture was crushed to obtain pre-modified attapulgite.

[0064] (2) Preparation of chitosan acetic acid solution: Add chitosan to 1wt% acetic acid solution to make the concentration of chitosan 2wt%, stir and disperse evenly, and set aside;

[0065] (3) Chitosan composite: According to the mass ratio of premodified attapulgite to chitosan 10:1, the premodified attapulgite obtained in step (1) is added to the chitosan acetic acid solution obtained in step (2), stirred (room temperature, 48h), dried (105℃, 2h), and ground and sieved through 150 mesh to obtain modified attapulgite.

[0066] (4) Modification of silica: Silica was added to N,N-dimethylformamide, stirred and dispersed evenly, and then succinic anhydride and KH550 were added. The reaction was then carried out under stirring and heating conditions (35℃, 2.5h), followed by centrifugation, washing and drying to obtain modified silica; wherein the mass ratio of silica, N,N-dimethylformamide, succinic anhydride and KH550 was 1:50:4:4.5;

[0067] (5) According to the mass ratio of 1.2:0.6:8, the modified attapulgite obtained in step (3) and the modified silica obtained in step (4) are added to water in sequence, stirred (35℃, 2.5h), and then centrifuged, washed and dried to obtain the reinforcing material.

[0068] Example 2

[0069] A silicone coating is prepared from the following raw materials by weight: 5g polydimethylsiloxane, 3g polyether-modified polydimethylsiloxane, 3g octamethylcyclotetrasiloxane, 2g triethoxysilane, 0.15g white spirit, 0.15g decadecane, 0.75g platinum curing agent, 2.4g reinforcing agent, 0.02g tackifier, 0.02g antistatic agent, 0.1g fluff powder, 0.08g matting agent, and 0.02g dispersant.

[0070] The preparation of the reinforcing material includes the following steps:

[0071] (1) Modification of attapulgite: attapulgite and sodium hydroxide were mixed at a mass ratio of 1:0.45 and then subjected to high temperature treatment (795℃, 1h). After treatment, the mixture was crushed to obtain pre-modified attapulgite.

[0072] (2) Preparation of chitosan acetic acid solution: Add chitosan to 0.9wt% acetic acid solution to make the concentration of chitosan 1.8wt%, stir and disperse evenly, and set aside;

[0073] (3) Chitosan composite: According to the mass ratio of premodified attapulgite to chitosan 9.5:1, the premodified attapulgite obtained in step (1) was added to the chitosan acetic acid solution obtained in step (2), stirred and treated (room temperature, 48h), dried (105℃, 2h), and ground and sieved through 150 mesh to obtain modified attapulgite.

[0074] (4) Modification of silica: Silica was added to N,N-dimethylformamide, stirred and dispersed evenly, and then succinic anhydride and KH550 were added. The reaction was then carried out under stirring and heating conditions (35℃, 2.5h), followed by centrifugation, washing and drying to obtain modified silica; wherein the mass ratio of silica, N,N-dimethylformamide, succinic anhydride and KH550 was 1:50:4.2:4.8;

[0075] (5) According to the mass ratio of 1.2:0.6:8, the modified attapulgite obtained in step (3) and the modified silica obtained in step (4) are added to water in sequence, stirred (35℃, 2.5h), and then centrifuged, washed and dried to obtain the reinforcing material.

[0076] Example 3

[0077] A silicone coating is prepared from the following raw materials by weight: 5g polydimethylsiloxane, 3g polyether-modified polydimethylsiloxane, 3g octamethylcyclotetrasiloxane, 2g triethoxysilane, 0.15g white spirit, 0.15g decadecane, 0.75g platinum curing agent, 2.4g reinforcing agent, 0.02g tackifier, 0.02g antistatic agent, 0.1g fluff powder, 0.08g matting agent, and 0.02g dispersant.

[0078] The preparation of the reinforcing material includes the following steps:

[0079] (1) Modification of attapulgite: attapulgite and sodium hydroxide were mixed at a mass ratio of 1:0.52 and then subjected to high temperature treatment (795℃, 1h). After the treatment was completed, the mixture was crushed to obtain pre-modified attapulgite.

[0080] (2) Preparation of chitosan acetic acid solution: Add chitosan to 0.95wt% acetic acid solution to make the concentration of chitosan 1.9wt%, stir and disperse evenly, and set aside;

[0081] (3) Chitosan composite: According to the mass ratio of premodified attapulgite to chitosan of 10.5:1, the premodified attapulgite obtained in step (1) was added to the chitosan acetic acid solution obtained in step (2), stirred and treated (room temperature, 48h), dried (105℃, 2h), and ground and sieved through 150 mesh to obtain modified attapulgite;

[0082] (4) Modification of silica: Silica was added to N,N-dimethylformamide, stirred and dispersed evenly, and then succinic anhydride and KH550 were added. The reaction was then carried out under stirring and heating conditions (35℃, 3h), followed by centrifugation, and then washing and drying to obtain modified silica; wherein the mass ratio of silica, N,N-dimethylformamide, succinic anhydride and KH550 was 1:50:4.2:4.8;

[0083] (5) According to the mass ratio of 1.2:0.65:8, the modified attapulgite obtained in step (3) and the modified silica obtained in step (4) are added to water in sequence, stirred (35℃, 2.5h), and then centrifuged, washed and dried to obtain the reinforcing material.

[0084] Example 4

[0085] A method for preparing a TPU-based material for a projection screen includes the following steps:

[0086] S1. Using a 120-mesh star wheel and a scraper, evenly coat one side of the TPU substrate with silicone adhesive (coating amount: 25g / m²). 2 After coating, a curing process is performed (120℃, 3 min), followed by natural cooling for 24 h to obtain the base coat.

[0087] S2. Weigh the raw materials for the silicone coating described in Example 1 according to the specified ratio, mix and disperse them evenly, and then coat them onto textured release paper (coating amount is 260g / m). 2After being treated at 80℃ for 2 minutes to reach a semi-vulcanized state, it is then covered on the base coating. Subsequently, it is pressure-shaped and baked (130℃, 3 minutes) by an 80kg circular pressure roller and a 2.5KG cylinder pressure to achieve complete vulcanization. Finally, the release paper is separated to obtain the silicone coating.

[0088] S3. Apply a mixed solvent to the adhesive coating (coating amount: 25g / m²). 2 After baking (130℃, 3 minutes), it is ready.

[0089] S4. Repeat steps S1 to S3 on the other side of the TPU substrate. After the process is completed, the TPU base material is obtained.

[0090] The preparation of silicone adhesive includes the following steps:

[0091] Mix 6g of hydrogen-containing polysiloxane, 3g of vinyl polysiloxane, 2g of dimethyl dichlorosilane, 1g of octamethylcyclotetrasiloxane, and 0.05g of platinum catalyst evenly, and then mix with 6g of white spirit to obtain the final product.

[0092] The mixed solvent is obtained by mixing the following raw materials in the indicated mass fractions: 50% dimethyl polysiloxane, 8% silica, 37% decadecane, and 5% dimethyl silicone oil.

[0093] Example 5

[0094] A method for preparing a TPU-based material for a projection screen includes the following steps:

[0095] S1. Using a 120-mesh star wheel and a scraper, evenly coat one side of the TPU substrate with silicone adhesive (coating amount: 25g / m²). 2 After coating, a curing process is performed (120℃, 3 min), followed by natural cooling for 24 h to obtain the base coat.

[0096] S2. Weigh the raw materials for the silicone coating described in Example 2 according to the specified ratio, mix and disperse them evenly, and then coat them onto textured release paper (coating amount is 260g / m). 2 After being treated at 80℃ for 2 minutes to reach a semi-vulcanized state, it is then covered on the base coating. Subsequently, it is pressure-shaped and baked (130℃, 3 minutes) by an 80kg circular pressure roller and a 2.5KG cylinder pressure to achieve complete vulcanization. Finally, the release paper is separated to obtain the silicone coating.

[0097] S3. Apply a mixed solvent to the adhesive coating (coating amount: 25g / m²). 2 After baking (130℃, 3 minutes), it is ready.

[0098] S4. Repeat steps S1 to S3 on the other side of the TPU substrate. After the process is completed, the TPU base material is obtained.

[0099] The preparation of silicone adhesive includes the following steps:

[0100] Mix 6g of hydrogen-containing polysiloxane, 3g of vinyl polysiloxane, 2g of dimethyl dichlorosilane, 1g of octamethylcyclotetrasiloxane, and 0.05g of platinum catalyst evenly, and then mix with 6g of white spirit to obtain the final product.

[0101] The mixed solvent is obtained by mixing the following raw materials in the indicated mass fractions: 50% dimethyl polysiloxane, 8% silica, 37% decadecane, and 5% dimethyl silicone oil.

[0102] Example 6

[0103] A method for preparing a TPU-based material for a projection screen includes the following steps:

[0104] S1. Using a 120-mesh star wheel and a scraper, evenly coat one side of the TPU substrate with silicone adhesive (coating amount: 25g / m²). 2 After coating, a curing process is performed (120℃, 3 min), followed by natural cooling for 24 h to obtain the base coat.

[0105] S2. Weigh the raw materials for the silicone coating described in Example 3 according to the specified ratio, mix and disperse them evenly, and then coat them onto textured release paper (coating amount is 260g / m). 2 After being treated at 80℃ for 2 minutes to reach a semi-vulcanized state, it is then covered on the base coating. Subsequently, it is pressure-shaped and baked (130℃, 3 minutes) by an 80kg circular pressure roller and a 2.5KG cylinder pressure to achieve complete vulcanization. Finally, the release paper is separated to obtain the silicone coating.

[0106] S3. Apply a mixed solvent to the adhesive coating (coating amount: 25g / m²). 2 After baking (130℃, 3 minutes), it is ready.

[0107] S4. Repeat steps S1 to S3 on the other side of the TPU substrate. After the process is completed, the TPU base material is obtained.

[0108] The preparation of silicone adhesive includes the following steps:

[0109] Mix 6g of hydrogen-containing polysiloxane, 3g of vinyl polysiloxane, 2g of dimethyl dichlorosilane, 1g of octamethylcyclotetrasiloxane, and 0.05g of platinum catalyst evenly, and then mix with 6g of white spirit to obtain the final product.

[0110] The mixed solvent is obtained by mixing the following raw materials in the indicated mass fractions: 50% dimethyl polysiloxane, 8% silica, 37% decadecane, and 5% dimethyl silicone oil.

[0111] Comparative Example 1

[0112] Compared with Example 1, Comparative Example 1 omits the pretreatment of retardant. Specifically, in Comparative Example 1, a silicone coating is prepared from the following raw materials by weight: 5g polydimethylsiloxane, 3g polyether-modified polydimethylsiloxane, 3g octamethylcyclotetrasiloxane, 2g triethoxysilane, 0.15g white spirit, 0.15g decadecane, 0.75g platinum curing agent, 2.2g reinforcing agent, 0.02g tackifier, 0.02g antistatic agent, 0.1g fluff powder, 0.08g matting agent, and 0.02g dispersant.

[0113] The preparation of the reinforcing material includes the following steps:

[0114] (1) Take the raw material of attapulgite, crush it, and set it aside;

[0115] (2) Preparation of chitosan acetic acid solution: Add chitosan to 1wt% acetic acid solution to make the concentration of chitosan 2wt%, stir and disperse evenly, and set aside;

[0116] (3) Chitosan composite: According to the mass ratio of attapulgite to chitosan of 10:1, the attapulgite obtained in step (1) is added to the chitosan acetic acid solution obtained in step (2), stirred (room temperature, 48h), dried (105℃, 2h), and ground and sieved through 150 mesh to obtain modified attapulgite;

[0117] (4) Modification of silica: Silica was added to N,N-dimethylformamide, stirred and dispersed evenly, and then succinic anhydride and KH550 were added. The reaction was then carried out under stirring and heating conditions (35℃, 2.5h), followed by centrifugation, washing and drying to obtain modified silica; wherein the mass ratio of silica, N,N-dimethylformamide, succinic anhydride and KH550 was 1:50:4:4.5;

[0118] (5) According to the mass ratio of 1.2:0.6:8, the modified attapulgite obtained in step (3) and the modified silica obtained in step (4) are added to water in sequence, stirred (35℃, 2.5h), and then centrifuged, washed and dried to obtain the reinforcing material.

[0119] Comparative Example 2

[0120] Compared with Example 1, Comparative Example 2 omits the chitosan modification treatment. Specifically, in Comparative Example 2, a silicone coating is prepared from the following raw materials by weight: 5g polydimethylsiloxane, 3g polyether-modified polydimethylsiloxane, 3g octamethylcyclotetrasiloxane, 2g triethoxysilane, 0.15g white spirit, 0.15g decadecane, 0.75g platinum vulcanizing agent, 2.2g reinforcing agent, 0.02g tackifier, 0.02g antistatic agent, 0.1g fluff powder, 0.08g matting agent, and 0.02g dispersant.

[0121] The preparation of the reinforcing material includes the following steps:

[0122] (1) Modification of attapulgite: attapulgite and sodium hydroxide were mixed at a mass ratio of 1:0.5 and then subjected to high temperature treatment (795℃, 1h). After the treatment was completed, the mixture was crushed to obtain pre-modified attapulgite.

[0123] (2) Modification of silica: Silica was added to N,N-dimethylformamide, stirred and dispersed evenly, and then succinic anhydride and KH550 were added. The reaction was then carried out under stirring and heating conditions (35℃, 2.5h), followed by centrifugation, washing and drying to obtain modified silica; wherein the mass ratio of silica, N,N-dimethylformamide, succinic anhydride and KH550 was 1:50:4:4.5;

[0124] (3) According to the mass ratio of 1.2:0.6:8, the pre-modified attapulgite obtained in step (1) and the modified silica obtained in step (2) are added to water in sequence, stirred (35℃, 2.5h), and then centrifuged, washed and dried to obtain the reinforcing material.

[0125] Comparative Example 3

[0126] Compared with Example 1, Comparative Example 3 omits the silica modification treatment. Specifically, in Comparative Example 3, a silicone coating is prepared from the following raw materials by weight: 5g polydimethylsiloxane, 3g polyether-modified polydimethylsiloxane, 3g octamethylcyclotetrasiloxane, 2g triethoxysilane, 0.15g white spirit, 0.15g decadecane, 0.75g platinum vulcanizing agent, 2.2g reinforcing agent, 0.02g tackifier, 0.02g antistatic agent, 0.1g fluff powder, 0.08g matting agent, and 0.02g dispersant.

[0127] The preparation of the reinforcing material includes the following steps:

[0128] (1) Modification of attapulgite: attapulgite and sodium hydroxide were mixed at a mass ratio of 1:0.5 and then subjected to high temperature treatment (795℃, 1h). After the treatment was completed, the mixture was crushed to obtain pre-modified attapulgite.

[0129] (2) Preparation of chitosan acetic acid solution: Add chitosan to 1wt% acetic acid solution to make the concentration of chitosan 2wt%, stir and disperse evenly, and set aside;

[0130] (3) Chitosan composite: According to the mass ratio of premodified attapulgite to chitosan 10:1, the premodified attapulgite obtained in step (1) is added to the chitosan acetic acid solution obtained in step (2), stirred (room temperature, 48h), dried (105℃, 2h), and ground and sieved through 150 mesh to obtain modified attapulgite.

[0131] (4) Take silicon dioxide and set aside;

[0132] (5) According to the mass ratio of 1.2:0.6:8, the modified attapulgite obtained in step (3) and the silica obtained in step (4) are added to water in sequence, stirred (35℃, 2.5h), and then centrifuged, washed and dried to obtain the reinforcing material.

[0133] The performance of the silicone coatings obtained in Example 1 and Comparative Examples 1-3 was tested using the following methods:

[0134] Abrasion resistance is tested in accordance with GB / T1768-2006. After coating, the coating is treated at 80℃ for 2 minutes and then at 130℃ for 3 minutes.

[0135] Weather resistance is tested in accordance with ISO 20340-2009.

[0136] Corrosion resistance test: Immerse in 6% sodium hydroxide solution first, then undergo accelerated corrosion test at 35°C.

[0137] The test results are shown in Table 1.

[0138] Table 1

[0139]

[0140]

[0141] As can be seen from Table 1, the silicone coating prepared by this invention is wear-resistant, corrosion-resistant, and has good weather resistance. The performance of the TPU-based material prepared in Example 4 was tested, and the results are shown in Table 2.

[0142] Table 2 Material testing results for Example 4

[0143]

[0144]

[0145] As can be seen from Table 2, the TPU-based material prepared by this invention has excellent overall performance.

[0146] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A silicone coating, characterized in that, It is prepared from the following raw materials in parts by weight: 1-5 parts polydimethylsiloxane, 1-5 parts polyether-modified polydimethylsiloxane, 0.5-4 parts octamethylcyclotetrasiloxane, 0.5-3.5 parts triethoxysilane, 0.1-0.2 parts white spirit, 0.1-0.2 parts decadecane, 0.5-1 parts platinum vulcanizing agent, 0.8-2.5 parts reinforcing agent, 0.01-0.03 parts tackifier, 0.01-0.03 parts antistatic agent, 0.5-2 parts fluff powder, 0.05-0.1 parts matting agent, and 0.01-0.03 parts dispersant; The preparation of the reinforcing material includes the following steps: (1) Modification of attapulgite: attapulgite is mixed with sodium hydroxide and subjected to high temperature treatment. After the treatment is completed, it is crushed to obtain pre-modified attapulgite. (2) Preparation of chitosan acetic acid solution: Add chitosan to acetic acid solution, stir and disperse evenly, and set aside; (3) Chitosan composite: The pre-modified attapulgite obtained in step (1) is added to the chitosan acetic acid solution obtained in step (2), stirred and dried, then ground and sieved to obtain modified attapulgite; (4) Modification of silica: Add silica to N,N-dimethylformamide, stir and disperse evenly, then add succinic anhydride and KH550, and then react under stirring and heating conditions. Then centrifuge, and then wash and dry to obtain modified silica. (5) The modified attapulgite obtained in step (3) and the modified silica obtained in step (4) are added to water in sequence, stirred, centrifuged, washed and dried to obtain the reinforcing material.

2. The silicone coating according to claim 1, characterized in that, In step (1), the mass ratio of attapulgite to sodium hydroxide is 1:0.4 to 0.65, the high temperature treatment temperature is 780 to 805℃, and the treatment time is 0.5 to 4h.

3. The silicone coating according to claim 1, characterized in that, In step (2), the concentration of the acetic acid solution is 0.5–1.2 wt%, and the concentration of chitosan is 1.2–2.5 wt%.

4. The silicone coating according to claim 1, characterized in that, In step (3), the mass ratio of pre-modified attapulgite to chitosan is 8-12:1; the stirring temperature is room temperature and the treatment time is 24-72h; the drying temperature is 105-110℃ and the sieve mesh is 100-150 mesh. In step (4), the heating temperature is 30-40℃ and the heating time is 0.5-6h; the mass ratio of silica, N,N-dimethylformamide, succinic anhydride and KH550 is 1:40-75:2.5-5.5:3.5-6.5; in step (5), the mass ratio of modified attapulgite, modified silica and water is 1-2:0.5-1:10; the stirring temperature is 30-40℃ and the stirring time is 0.5-4h.

5. The application of the silicone coating according to any one of claims 1 to 4 in the preparation of TPU-based projection screens.

6. A method for preparing a TPU-based material for a projection screen, characterized in that, Includes the following steps: S1. Apply silicone adhesive evenly to one side of the TPU substrate, then cure and cool to obtain the base coating. S2. Weigh the raw materials of the silicone coating according to any one of claims 1 to 4 in proportion, mix and disperse evenly, then coat it onto release paper, treat it at 75 to 85°C to reach a semi-vulcanized state, and then cover it onto the base coating; subsequently, perform pressure setting and baking treatment to achieve complete vulcanization, and finally separate the release paper to obtain the silicone coating. S3. Apply the mixed solvent to the adhesive coating and bake it. S4. Repeat steps S1 to S3 on the other side of the TPU substrate. After the process is completed, the TPU base material is obtained.

7. The preparation method according to claim 6, characterized in that, In step S1, the preparation of the silicone adhesive includes the following steps: 2-7 parts by weight of hydrogen-containing polysiloxane, vinyl polysiloxane, dimethyl dichlorosilane, octamethylcyclotetrasiloxane, and platinum catalyst are mixed evenly, respectively, and then mixed with 4-8 parts by weight of white spirit to obtain the final product. The coating amount of silicone adhesive is 20-30 g / m². 2 The curing temperature is 115-125℃, and the curing time is 1-5 minutes.

8. The preparation method according to claim 6, characterized in that, In step S2, the coating amount on the release paper is 200-300 g / m². 2 The treatment time is 1 to 5 minutes at 75 to 85°C; the baking temperature is 125 to 135°C and the baking time is 1 to 5 minutes.

9. The preparation method according to claim 6, characterized in that, In step S3, the mixed solvent is obtained by mixing the following raw materials in the following mass fractions: 45-55% dimethylpolysiloxane, 5-15% silica, 25-35% decadecane, and 3-10% dimethyl silicone oil; The coating amount is 20-30 g / m² 2 The baking temperature is 125-130℃, and the baking time is 1-5 minutes.

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