High-strength colorful TPU composite decorative film and preparation method thereof

Abstract

The invention discloses a high-strength colorful TPU composite decorative film and a preparation method thereof, and belongs to the field of materials.The high-strength colorful TPU composite decorative film comprises an anti-fouling layer, an appearance layer, an anti-bending layer, a framework layer and a substrate layer which are sequentially compounded from outside to inside, and the two sides of the anti-bending layer are each coated with an adhesive layer. The manufactured high-strength colorful TPU composite decorative film has good mechanical properties such as tensile strength and tearing strength, excellent dimensional stability and 50%-95% ductility, does not rebound and is used for an edge covering processing and forming process of a curved surface material, in addition, the surface of the TPU composite decorative film has the design advantages of various textures, rich colors, diversified patterns and the like, and the TPU composite decorative film has a good market prospect. And the coating has the characteristics of surface smudginess resistance and wide application in the fields of aerospace, home textiles, home decorations and the like.

Description

Technical Field

[0001] The invention relates to a high-strength colorful TPU composite decorative film and a preparation method thereof, and belongs to the field of materials. Background Art

[0002] Polyurethane film is becoming increasingly popular due to its superior performance and environmental protection concept. TPU not only has the characteristics of high tension, high tensile force, strong and aging resistance, but is also a mature environmentally friendly material. The advantages of TPU film in the field of decorative materials mainly include wear resistance, oil resistance, good flexibility, protection and decorative effects, extended service life, and improved aesthetics. Especially in the field of wallpaper, TPU materials have successfully replaced PVC materials due to their environmental protection and non-toxic characteristics. However, the existing TPU-based wallpaper decorative materials can only be used on flat decorative substrates. For curved decorative parts, they are difficult to apply due to their limited mechanical strength and ductility. Summary of the invention

[0003] In view of this, the present invention provides a high-strength and colorful TPU composite decorative film and a preparation method thereof, using dry coating-lamination as the production process and introducing a bending-resistant layer to successfully prepare a high-strength, high-ductility, and colorful TPU composite decorative film.

[0004] In order to achieve the above object, the present invention adopts the following technical solution: A high-strength TPU composite decorative film comprises an anti-fouling layer, an appearance layer, an anti-bending layer, a skeleton layer and a base layer which are composited in sequence from outside to inside, and adhesive layers are coated on both sides of the anti-bending layer.

[0005] On the basis of the above technical solution, the present invention is further limited as follows: Furthermore, the anti-bending layer is any one of PET, PC, PMMA, PE, PVC, and PP.

[0006] Furthermore, the thickness of the anti-bending layer is 0.01mm-0.075mm.

[0007] Furthermore, the appearance layer also includes a heat-resistant foaming layer, and the heat-resistant foaming layer is obtained by PP foaming, PBAT foaming, PE foaming, PU foaming, TPEE foaming, solvent-free foaming or AB component foaming.

[0008] Furthermore, the thickness of the high-strength TPU composite decorative film is 0.2 mm to 0.4 mm.

[0009] The present invention also provides a method for preparing the high-strength TPU composite decorative film, the steps of which are as follows: (1) Mixing the base material, DMF and MEK and stirring them evenly, adding the base additive and mixing them evenly to obtain a base coating, coating it on the release surface of the polyester release film, and drying it to obtain a base layer; (2) Mixing the skeleton base material, DMF and MEK and stirring them evenly, adding the skeleton additive and mixing them evenly to obtain a skeleton coating, coating it on the release surface of the polyester release film, and drying it to obtain a skeleton layer; (3) Mixing and stirring the hot melt adhesive masterbatch, DMF and MEK evenly, adding an adhesive additive and mixing evenly to obtain an adhesive coating, coating the coating on the release surface of the polyester release film, and baking the coating until it is semi-dry to obtain an adhesive layer; (4) Compounding and drying the anti-bending layer and the adhesive layer, and sequentially curing and peeling the skeleton layer and the base layer on one side of the adhesive layer to obtain a semi-finished product; (5) Mixing a polyurethane resin and an appearance additive to obtain an appearance coating, coating the coating on a release surface of a polyester release film, and drying the coating to obtain an appearance layer; (6) Laminating the adhesive layer to the other side of the anti-bending layer in the semi-finished product, and laminating the appearance layer by curing and peeling; (7) The anti-fouling surface treatment liquid is coated on the surface of the appearance layer, and a high-strength TPU composite decorative film is obtained after drying.

[0010] On the basis of the above technical solution, the present invention is further limited as follows: Further, the mass ratio of the base material, DMF, and MEK is 1:2:2, and the mass percentages of the raw materials of the base additives in the base layer are: anti-hydrolysis agent 0.03%-1.5%, anti-yellowing agent 0.1%-1.5%, anti-mildew and antibacterial agent 5%-10%, titanium dioxide 5%-10%, flame retardant 5%-15%, and color fixing agent 0.3%-1%, and the balance is a mixture of the base material, DMF, and MEK; The mass ratio of the skeleton base material, DMF and MEK is 1:2:2. The mass percentages of the raw materials of the skeleton additives in the skeleton layer are: anti-hydrolysis agent 0.03%-1.5%, anti-yellowing agent 0.1%-1.5%, anti-mildew and antibacterial agent 5%-10%, flame retardant 5%-15%, and the remainder is a mixture of the skeleton base material, DMF and MEK. The mass ratio of hot melt adhesive masterbatch, DMF and MEK is 1:2:2, and the mass percentage of the raw materials of the adhesive additive in the adhesive layer is: 0.03%-1.5% of hydrolysis resistance agent, 10%-15% of tackifying resin, 5%-10% of flame retardant, and the balance is a mixture of hot melt adhesive masterbatch, DMF and MEK; The mass fraction of polyurethane resin is 70-100 parts, and the appearance additives include the following raw materials in mass fractions: 0.03-1.5 parts of anti-hydrolysis agent, 0.1-1.5 parts of anti-yellowing agent, 5-10 parts of mildew and antibacterial agent, 5-15 parts of flame retardant, and 0.3-1 parts of color fixing agent; The anti-fouling surface treatment liquid is composed of AB components, the mass ratio of AB components is 5-15:10-15, component A is fluorine-containing silicone, and component B includes the following raw materials in mass parts: 0.5-5 parts of curing agent, 0.5-1 parts of wear-resistant additive, 0.5-1 parts of scratch-resistant additive, and 0.5-1 parts of color powder.

[0011] Furthermore, the base material is any one of PVDF, polyurethane or PVC; The skeleton base material is any one of TPU masterbatch, polyurethane or PVC; The hardness of polyurethane resin is greater than 85A; The residual bonding strength of polyester release film is 30-70%; Further, drying is to dry the coated product at a temperature of 40°C-160°C in a bridge oven in an increasing and decreasing manner; The lamination is carried out by a laminating wheel, the laminating wheel pressure is 40-80kgf, and the laminating wheel temperature is 100-150℃; The coating was uniformly applied using a slot coating head of a bridge type coating machine.

[0012] Furthermore, the method also includes printing on the surface of the appearance layer.

[0013] The beneficial effects of the present invention are: The high-strength and colorful TPU composite decorative film produced by the present invention has good mechanical properties such as tensile strength and tear strength, excellent dimensional stability, and 50%-95% ductility without rebound, and is used for the edge processing and molding process of curved surface materials. In addition, the surface of this TPU composite decorative film has design advantages such as diverse textures, rich colors, and diverse patterns, as well as surface resistance to dirt, and is widely used in the fields of aerospace, home textiles, and home furnishings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the structure of the high-strength and colorful TPU composite decorative film layer of the present invention.

[0015] In the accompanying drawings, the components represented by the reference numerals are listed as follows: 1. Anti-fouling layer, 2. Appearance layer, 3. Anti-bending layer, 4. Skeleton layer, 5. Base layer, 6. Adhesive layer. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Example 1 like Figure 1 As shown, the high-strength colorful TPU composite decorative film includes an anti-fouling layer, an appearance layer, an anti-bending layer, a skeleton layer and a base layer which are composited in sequence from the outside to the inside, wherein both sides of the anti-bending layer are coated with adhesive layers respectively.

[0018] The preparation method of high-strength colorful TPU composite decorative film is as follows: (1) The base layer is mixed evenly according to the mass ratio of PVDF powder: DMF: MEK of 1:2:2, and 1 part of hydrolysis resistance agent, 1 part of yellowing resistance agent, 8 parts of mildew and antibacterial agent, 8 parts of titanium dioxide, 10 parts of flame retardant, and 0.5 parts of color fixing agent are added to make the raw materials 100 parts by mass, and a uniform base layer coating is prepared. The fully mixed base layer coating is evenly coated on the release surface of the polyester release film (generally a plain release film) with a residual bonding force of 50% using the slit coating head of a bridge coating machine, and the coated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method to obtain the base layer; (2) The skeleton layer is stirred evenly according to the mass ratio of TPU masterbatch: DMF: MEK of 1:2:2, and 1 part of hydrolysis resistance agent, 1 part of yellowing resistance agent, 8 parts of mildew and antibacterial agent, and 10 parts of flame retardant are added to make the raw materials form 100 parts by mass, and a uniform skeleton layer coating is prepared. The fully mixed skeleton layer coating is evenly coated on the release surface of the polyester release film with a residual bonding force of 50% using the slit coating head of a bridge coating machine, and the coated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method to obtain the skeleton layer; (3) The adhesive layer is mixed evenly according to the mass ratio of hot melt adhesive masterbatch: DMF: MEK of 1:2:2, and 1 part of hydrolysis resistance agent, 12 parts of tackifying resin and 10 parts of flame retardant are added to make the raw materials form 100 parts by mass, and a uniform adhesive layer coating is prepared. The fully mixed adhesive layer coating is evenly coated on the release surface of the polyester release film with a residual bonding strength of 60% (different textured release films can be selected according to needs) using the slit coating head of a bridge coating machine, and the coated product is baked at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method until it is semi-dry, thereby obtaining an adhesive layer; (4) The anti-bending layer is 0.025mm PET. The adhesive layer and the anti-bending layer are compounded by a laminating wheel. The laminating wheel pressure is 60kgf and the laminating wheel temperature is 120℃. The laminated product is dried at a temperature of 40℃-160℃ in a bridge oven using a temperature increasing and decreasing method. (5) The aforementioned materials are ripened, peeled, and rolled up for later use to obtain a semi-finished product; (6) The appearance layer is made of polyurethane resin with a hardness greater than 85A. A uniform thermoplastic polyurethane coating is prepared according to 80 parts of polyurethane resin, 1 part of hydrolysis resistance agent, 1 part of yellowing resistance agent, 10 parts of mildew and antibacterial agent, 10 parts of flame retardant, 1 part of color fixer and appropriate amount of color powder. The fully mixed polyurethane coating is evenly coated on the release surface of the polyester release film with a residual bonding force of 45% using the slit coating head of a bridge coating machine. The coated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method to obtain the appearance layer. The number of appearance layers can be designed from single layer to multiple layers according to the design requirements such as color and pattern; (7) The adhesive layer is prepared in the same manner as in step (3); (8) The semi-finished product prepared in the fifth step is again laminated with the adhesive layer and the back of the semi-finished product anti-bending layer by a laminating wheel, the laminating wheel pressure is 60 kgf, the laminating wheel temperature is 120°C, and the laminated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method; (9) The product matured in step 8 is peeled off, inspected, cut, and rolled up again, and a customized pattern is applied to the surface of the appearance layer using a digital printing process according to customization requirements; (10) The anti-fouling surface treatment liquid is composed of AB components, 5-15 parts of component A (fluorinated silicone), 10-15 parts of component B (3 parts of curing agent, 1 part of wear-resistant additive, 1 part of scratch-resistant additive, and 0.5-1 part of pearlescent powder) are mixed and stirred to form a scratch-resistant and anti-fouling surface treatment liquid. The fully mixed scratch-resistant and anti-fouling surface treatment liquid is evenly coated on the surface of the pattern prepared in step (9) using the slit coating head of a bridge coating machine. The mesh roller is 120 mesh. The coated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method, and a secondary surface treatment process is performed to obtain a high-strength colorful TPU composite decorative film with a total thickness of 0.2-0.4 mm. The performance of the film is tested. The results are shown in Table 1.

[0019] Table 1 Performance test results

[0020] *Stain resistance test media: alcohol, naphtha, butter, mayonnaise, cream coffee, melted chocolate, broth, orange juice, ketchup, mustard, lipstick, pesticides, disinfectants, fire extinguishers.

[0021] Example 2 The preparation method of high-strength colorful TPU composite decorative film is as follows: (1) The base layer is stirred evenly according to the mass ratio of polyurethane:DMF:MEK of 1:2:2, and 0.03 parts of hydrolysis resistance agent, 0.1 parts of yellowing resistance agent, 5 parts of mildew and antibacterial agent, 5 parts of titanium dioxide, 5 parts of flame retardant, and 0.3 parts of color fixing agent are added to make the raw materials form 100 parts by mass, and a uniform base layer coating is prepared. The fully mixed base layer coating is evenly coated on the release surface of the polyester release film (generally a plain release film) with a residual bonding force of 30% using the slit coating head of a bridge coating machine, and the coated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method to obtain a base layer; (2) The skeleton layer is stirred evenly according to the mass ratio of polyurethane:DMF:MEK of 1:2:2, and 0.03 parts of hydrolysis resistance agent, 0.1 parts of yellowing resistance agent, 5 parts of mildew and antibacterial agent, and 5 parts of flame retardant are added to make the raw materials 100 parts by mass, and a uniform skeleton layer coating is prepared. The fully mixed skeleton layer coating is evenly coated on the release surface of the polyester release film with a residual bonding strength of 30% using the slit coating head of a bridge coating machine, and the coated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method to obtain the skeleton layer; (3) The adhesive layer is mixed evenly according to the mass ratio of hot melt adhesive masterbatch: DMF: MEK of 1:2:2, and 1.5 parts of hydrolysis resistance agent, 10 parts of tackifying resin and 5 parts of flame retardant are added to make the raw materials form 100 parts by mass, and a uniform adhesive layer coating is prepared. The fully mixed adhesive layer coating is evenly coated on the release surface of the polyester release film with a residual bonding force of 30% (different textured release films can be selected according to needs) using the slit coating head of a bridge coating machine, and the coated product is baked at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method until it is semi-dry, thereby obtaining an adhesive layer; (4) The anti-bending layer is 0.01mm PC. The adhesive layer and the anti-bending layer are compounded by a laminating wheel. The laminating wheel pressure is 40kgf and the laminating wheel temperature is 100℃. The laminated product is dried at a temperature of 40℃-160℃ in a bridge oven by increasing and decreasing the temperature. (5) The aforementioned materials are ripened, peeled, and rolled up for later use to obtain a semi-finished product; (6) The appearance layer is made of polyurethane resin with a hardness of more than 85A. The thermoplastic polyurethane coating is prepared by mixing 70 parts of polyurethane resin, 0.03 parts of hydrolysis resistance agent, 0.1 parts of yellowing resistance agent, 5 parts of mildew and antibacterial agent, 5 parts of flame retardant, 0.3 parts of color fixative, and appropriate amount of color powder. The fully mixed polyurethane coating is evenly coated on the release surface of the polyester release film with a residual bonding force of 30% using the slit coating head of a bridge coating machine. The coated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method to obtain the appearance layer. The number of appearance layers can be designed from single layer to multiple layers according to the design requirements of color, pattern, etc. (7) The adhesive layer is prepared in the same manner as in step (3); (8) The semi-finished product is laminated again with the adhesive layer and the back of the semi-finished product anti-bending layer through a laminating wheel, the laminating wheel pressure is 40kgf, the laminating wheel temperature is 100℃, and the laminated product is dried at a temperature of 40℃-160℃ in a bridge oven using a temperature increasing and decreasing method; (9) The matured product is peeled, inspected, cut, and rolled again, and a customized pattern is applied to the surface of the appearance layer using a digital printing process according to customization requirements; (10) The anti-fouling surface treatment liquid is composed of AB components, according to 5-15 parts of component A (fluorinated silicone), 10-15 parts of component B (0.5 parts of curing agent, 0.5 parts of wear-resistant additive, 0.5 parts of scratch-resistant additive, and 0.5-1 parts of fluorescent powder), mixed and stirred to form a scratch-resistant and anti-fouling surface treatment liquid, and the fully mixed scratch-resistant and anti-fouling surface treatment liquid is evenly coated on the surface of the pattern layer prepared in step (9) using a slit coating head of a bridge coating machine, the mesh roller is 120 mesh, and the coated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method, and a secondary surface treatment process is performed to obtain a high-strength colorful TPU composite decorative film with a total thickness of 0.2-0.4 mm.

[0022] Example 3 The preparation method of high-strength colorful TPU composite decorative film is as follows: (1) The base layer is stirred evenly according to the mass ratio of PVC:DMF:MEK of 1:2:2, and 1.5 parts of hydrolysis resistance agent, 1.5 parts of yellowing resistance agent, 10 parts of mildew and antibacterial agent, 10 parts of titanium dioxide, 15 parts of flame retardant and 1 part of color fixing agent are added to make the raw materials form 100 parts by mass, and a uniform base layer coating is prepared. The fully mixed base layer coating is evenly coated on the release surface of the polyester release film (generally a plain release film) with a residual bonding force of 70% using the slit coating head of a bridge coating machine, and the coated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method to obtain the base layer; (2) The skeleton layer is stirred evenly according to the mass ratio of PVC:DMF:MEK of 1:2:2, and 1.5 parts of hydrolysis resistance agent, 1.5 parts of yellowing resistance agent, 10 parts of mildew and antibacterial agent, and 15 parts of flame retardant are added to make the raw materials form 100 parts by mass, and a uniform skeleton layer coating is prepared. The fully mixed skeleton layer coating is evenly coated on the release surface of the polyester release film with a residual bonding strength of 70% using the slit coating head of a bridge coating machine, and the coated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method to obtain the skeleton layer; (3) The adhesive layer is mixed evenly according to the mass ratio of hot melt adhesive masterbatch: DMF: MEK of 1:2:2, and 1.5 parts of hydrolysis resistance agent, 15 parts of tackifying resin and 10 parts of flame retardant are added to make the raw materials form 100 parts by mass, and a uniform adhesive layer coating is prepared. The fully mixed adhesive layer coating is evenly coated on the release surface of the polyester release film with a residual bonding strength of 70% (different textured release films can be selected according to needs) using the slit coating head of a bridge coating machine, and the coated product is baked at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method until it is semi-dry, thereby obtaining an adhesive layer; (4) The anti-bending layer is 0.075mm PE. The adhesive layer and the anti-bending layer are compounded by a laminating wheel. The laminating wheel pressure is 80kgf and the laminating wheel temperature is 150℃. The laminated products are dried at a temperature of 40℃-160℃ in a bridge oven using a temperature increasing and decreasing method. (5) The aforementioned samples are aged, peeled, and rolled up for later use to obtain semi-finished products; (6) The appearance layer is made of polyurethane resin with a hardness of more than 85A. A thermoplastic polyurethane coating is prepared by mixing 100 parts of polyurethane resin, 1.5 parts of hydrolysis resistance agent, 1.5 parts of yellowing resistance agent, 10 parts of mildew and antibacterial agent, 15 parts of flame retardant, 1 part of color fixer, and appropriate amount of color powder. The fully mixed polyurethane coating is evenly coated on the release surface of the polyester release film with a residual bonding strength of 70% using the slit coating head of a bridge coating machine. The coated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method to obtain the appearance layer. The number of appearance layers can be designed from single layer to multiple layers according to the design requirements of color, pattern, etc. (7) The adhesive layer is prepared in the same manner as in step (3); (8) The semi-finished product prepared in step (5) is again laminated with the adhesive layer and the back of the semi-finished product anti-bending layer by a laminating wheel, the laminating wheel pressure is 80 kgf, the laminating wheel temperature is 150°C, and the laminated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method; (9) The product matured in step (8) is peeled off, inspected, cut, and rolled up again, and a customized pattern is applied to the surface of the appearance layer using a digital printing process according to customization requirements; (10) The anti-fouling surface treatment liquid is composed of AB components, 5-15 parts of component A (fluorinated silicone), and 10-15 parts of component B (5 parts of curing agent, 1 part of wear-resistant additive, 1 part of scratch-resistant additive, and 1 part of gradient color powder). The components are mixed and stirred to form a scratch-resistant and anti-fouling surface treatment liquid. The fully mixed scratch-resistant and anti-fouling surface treatment liquid is evenly coated on the surface of the pattern layer prepared in step (9) using a slit coating head of a bridge coating machine. The mesh roller is 120 mesh. The coated product is dried at a temperature of 40°C-160°C in a bridge oven using a temperature increasing and decreasing method, and a secondary surface treatment process is performed to obtain a high-strength colorful TPU composite decorative film with a total thickness of 0.2-0.4 mm.

Claims

1. A high-strength TPU composite decorative film, characterized in that: The invention comprises an anti-fouling layer, an appearance layer, an anti-bending layer, a skeleton layer and a base layer which are compounded in sequence from the outside to the inside, and adhesive layers are coated on both sides of the anti-bending layer respectively.

2. The high-strength TPU composite decorative film according to claim 1, characterized in that: The anti-bending layer is any one of PET, PC, PMMA, PE, PVC, and PP.

3. The high-strength TPU composite decorative film according to claim 2, characterized in that: The anti-bending layer has a thickness of 0.01 mm to 0.075 mm.

4. The high-strength TPU composite decorative film according to claim 1, characterized in that: The appearance layer also includes a heat-resistant foaming layer, and the heat-resistant foaming layer is obtained by PP foaming, PBAT foaming, PE foaming, PU foaming, TPEE foaming, solvent-free foaming or AB component foaming.

5. The high-strength TPU composite decorative film according to any one of claims 1 to 4, characterized in that: The thickness of the high-strength TPU composite decorative film is 0.2 mm-0.4 mm.

6. A method for preparing a high-strength TPU composite decorative film, characterized in that: Here are the steps: (1) mixing and stirring a base material, DMF and MEK, adding a base additive and mixing evenly to obtain a base coating, coating the base coating on a release surface of a polyester release film, and drying the base coating to obtain a base layer; (2) mixing and stirring the skeleton base material, DMF and MEK evenly, adding a skeleton auxiliary agent and mixing evenly to obtain a skeleton coating, coating the coating on the release surface of the polyester release film, and drying to obtain a skeleton layer; (3) mixing and stirring the hot melt adhesive masterbatch, DMF and MEK evenly, adding an adhesive additive and mixing evenly to obtain an adhesive coating, coating the coating on the release surface of the polyester release film, and baking the coating until it is semi-dry to obtain an adhesive layer; (4) Compounding and drying the anti-bending layer and the adhesive layer, and curing and peeling the skeleton layer and the base layer on one side of the adhesive layer to obtain a semi-finished product; (5) mixing a polyurethane resin and an appearance additive to obtain an appearance coating, coating the coating on a release surface of a polyester release film, and drying the coating to obtain an appearance layer; (6) laminating the adhesive layer to the other side of the anti-bending layer in the semi-finished product, and laminating the appearance layer by curing and peeling; (7) coating the anti-fouling surface treatment liquid on the surface of the appearance layer, and drying to obtain a high-strength TPU composite decorative film.

7. The method for preparing the high-strength TPU composite decorative film according to claim 6, characterized in that: The mass ratio of the base material, DMF and MEK is 1:2:2, and the mass percentages of the raw materials of the base additives in the base layer are: anti-hydrolysis agent 0.03%-1.5%, anti-yellowing agent 0.1%-1.5%, anti-mildew and antibacterial agent 5%-10%, titanium dioxide 5%-10%, flame retardant 5%-15%, and color fixing agent 0.3%-1%; The mass ratio of the skeleton base material, DMF and MEK is 1:2:2, and the mass percentages of the raw materials of the skeleton additives in the skeleton layer are: anti-hydrolysis agent 0.03%-1.5%, anti-yellowing agent 0.1%-1.5%, anti-mildew and antibacterial agent 5%-10%, and flame retardant 5%-15%; The mass ratio of hot melt adhesive masterbatch, DMF and MEK is 1:2:2, and the mass percentage of the raw materials of the bonding aid in the bonding layer is: hydrolysis resistance agent 0.03%-1.5%, tackifying resin 10%-15%, flame retardant 5%-10%; The mass fraction of polyurethane resin is 70-100 parts, and the appearance additives include the following raw materials in mass fractions: 0.03-1.5 parts of anti-hydrolysis agent, 0.1-1.5 parts of anti-yellowing agent, 5-10 parts of mildew and antibacterial agent, 5-15 parts of flame retardant, and 0.3-1 parts of color fixing agent; The anti-fouling surface treatment liquid is composed of AB components, the mass ratio of AB components is 5-15:10-15, component A is fluorine-containing silicone, and component B includes the following raw materials in mass parts: 0.5-5 parts of curing agent, 0.5-1 parts of wear-resistant additive, 0.5-1 parts of scratch-resistant additive, and 0.5-1 parts of color powder.

8. The method for preparing the high-strength TPU composite decorative film according to claim 7, characterized in that: The base material is any one of PVDF, polyurethane or PVC; The skeleton base material is any one of TPU masterbatch, polyurethane or PVC; The hardness of polyurethane resin is greater than 85A; The residual bonding strength of polyester release film is 30-70%.

9. The method for preparing the high-strength TPU composite decorative film according to claim 6, characterized in that: Drying is to dry the coated products at a temperature of 40°C-160°C in a bridge oven in a manner of increasing and decreasing temperature; The lamination is carried out by a laminating wheel, the laminating wheel pressure is 40-80kgf, and the laminating wheel temperature is 100-150℃; The coating was uniformly applied using a slot coating head of a bridge coating machine.

10. The method for preparing the high-strength TPU composite decorative film according to claim 6, characterized in that: It also includes the operation of printing on the surface of the appearance layer.

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