TPU (Thermoplastic Polyurethane) foaming film with non-deformable three-dimensional grains after multiple hot pressing and preparation method thereof

Abstract

The invention relates to the technical field of TPU (Thermoplastic Polyurethanes), in particular to a TPU foamed film with non-deformable three-dimensional grains after multiple hot pressing and a preparation method thereof. The TPU foaming film comprises a texture layer and a TPU foaming layer, the texture layer is arranged on the upper surface of the TPU foaming layer, a plurality of grooves are formed in the upper surface of the TPU foaming layer, the lower end of the texture layer extends into the grooves to form inserting blocks, the inserting blocks are connected with the grooves in a clamped mode, the texture layer is formed by coating a composite PU coating, the composite PU coating permeates into the grooves and is cured into the inserting blocks, and the TPU foaming layer is arranged on the upper surface of the TPU foaming layer. The grooves and the inserting blocks form a rivet type mechanical lock catch structure, layering of the TPU foaming layer and the texture layer after two times of hot pressing in the production process is avoided, meanwhile, three-dimensional grains do not deform after the texture layer is subjected to multiple times of hot pressing, and in other words, the texture layer has excellent adhesive force, excellent heat resistance, a good fixing form and excellent stability performance, and the service life of the TPU foaming layer is prolonged. The composite material has bending resistance, can highlight the stereoscopic impression of the surface texture of a product, and can keep a clear stereoscopic effect and multi-layer hand feeling after multiple times of hot-pressing physical processing. The preparation method of the TPU foaming film is simple in process, easy to control in operation, extremely low in reject ratio, high in yield, good in economic effect and beneficial to industrial mass production.

Description

Technical Field

[0001] The present invention relates to the technical field of TPU, and specifically relates to a TPU foamed film with unchanged three-dimensional texture after multiple hot presses and a preparation method thereof. Background Art

[0002] TPU foamed films have currently been widely used. They have characteristics such as light weight, softness, good elasticity, and excellent mechanical properties, and can be applied to various fabrics such as clothing, tents, shoe materials, and automotive interiors, as well as other products. In order to meet the needs of consumers and highlight the three-dimensional sense of the film layer, the existing TPU foamed films form an uneven texture layer on the surface of the TPU foamed layer. However, most of the texture layers are not wear-resistant and not resistant to bending during use, and the surface texture of the material deforms after multiple hot presses in the production process, losing the texture effect. Summary of the Invention

[0003] In order to overcome the disadvantages and deficiencies existing in the prior art, the purpose of the present invention is to provide a TPU foamed film with unchanged three-dimensional texture after multiple hot presses. This TPU foamed film has excellent wear resistance, good adhesion, ultraviolet aging resistance, and heat resistance, is easy to use, and has a wide range of applications.

[0004] The preparation method of the TPU foamed film with unchanged three-dimensional texture after multiple hot presses in the present invention has a simple process, is easy to control, has a low defective rate, and has good economic effects, which is conducive to large-scale industrial production. The prepared TPU foamed film has stable quality. Its texture layer has unchanged three-dimensional texture after multiple hot presses, that is, while the TPU foamed film has excellent wear resistance, it also has good adhesion, ultraviolet aging resistance, heat resistance, bending resistance, and superior comprehensive performance.

[0005] The purpose of the present invention is achieved through the following technical solutions: A TPU foamed film with unchanged three-dimensional texture after multiple hot presses includes a texture layer and a TPU foamed layer. The texture layer is disposed on the upper surface of the TPU foamed layer. Multiple grooves are formed on the upper surface of the TPU foamed layer. The multiple grooves are distributed in a matrix. The cross-section of the groove is an inverted trapezoid. An insertion block extends from the lower end of the texture layer into the groove, and the insertion block is clamped with the groove.

[0006] Further, the depth of the groove is 25 - 35 μm, the distance between two adjacent grooves is 95 - 105 μm. Among them, the width of the top of the cross-section of the groove is 45 - 55 μm, and the width of the bottom is 25 - 35 μm.

[0007] Further, the thickness of the texture layer is 80 - 100 μm; the thickness of the TPU foamed layer is 0.4 - 1.2 cm.

[0008] Further, the texture layer is coated with a composite PU coating.

[0009] The TPU foamed film with unchanged three-dimensional texture after multiple hot presses of the present invention has a clever structure. There are grooves with an inverted trapezoidal cross-section on the surface of the TPU foamed layer. The lower end of the texture layer extends into the grooves with insertion blocks, so that the composite PU coating penetrates into the grooves and cures into the insertion blocks. The grooves and the insertion blocks form a "rivet"-type mechanical locking structure, enhancing mechanical interlocking, making the connection between the TPU foamed layer and the texture layer firm, and avoiding delamination of the TPU foamed layer and the texture layer after two hot presses in the production process. While the texture layer has excellent adhesion, it also has excellent heat resistance, and can highlight the three-dimensional sense of the product.

[0010] Furthermore, the preparation method of the composite PU coating includes the following steps:

[0011] A1. Place the diol in a reaction vessel, stir and heat up to 115 - 130 °C, control the pressure in the reaction vessel to be -0.02 - 0.06 MPa, and dehydrate; then fill with nitrogen, cool down to 75 - 85 °C, add isophorone diisocyanate and a catalyst, carry out a catalytic reaction for 1 - 3 h, then cool down to 65 - 75 °C, add 1-(furan-2-yl)-neopentane-1,3-diol for a chain extension reaction for 1 - 2 h, and then add methyl ethyl ketoxime for a capping reaction for 1 - 2 h. After the reaction is completed, mixture one is obtained;

[0012] A2. Raise the temperature to 70 - 80 °C, add silica sol and alumina nanoparticles to mixture one, stir evenly and carry out ultrasonic treatment for 1 - 2 h to obtain mixture two;

[0013] A3. Cool down to room temperature, add bismaleimide and epoxy resin to mixture two, and stir evenly to obtain the composite PU coating.

[0014] Furthermore, the molar ratio of the diol, 1-(furan-2-yl)-neopentane-1,3-diol, methyl ethyl ketoxime to isophorone diisocyanate is 1:0.4 - 0.8:0.2 - 0.6:1 - 2.

[0015] Furthermore, the diol is at least one of polycaprolactone diol, polytetrahydrofuran diol and polyoxypropylene diol.

[0016] Furthermore, the molar ratio of bismaleimide to 1-(furan-2-yl)-neopentane-1,3-diol is 1:2.2 - 2.5.

[0017] Furthermore, the addition amount of the epoxy resin is 15 - 25% of the total mass of the diol, 1-(furan-2-yl)-neopentane-1,3-diol, methyl ethyl ketoxime and isophorone diisocyanate.

[0018] Further, the epoxy resin used is bisphenol A epoxy resin with an epoxy value of 0.46 from Shanghai Complex High-Tech Materials Co., Ltd.

[0019] Further, the total amount of the silica sol and alumina nanoparticles added is 8-16% of the total mass of the diol, 1-(furan-2-yl)-neopentane-1,3-diol, methyl ethyl ketoxime and isophorone diisocyanate, and the mass ratio of the silica sol to the alumina nanoparticles is 1:0.3-0.7.

[0020] Further, the particle size of the alumina nanoparticles is 50-100 nm.

[0021] Further, the preparation method of the silica sol includes the following steps: tetraethyl orthosilicate, deionized water and absolute ethanol are prepared according to a molar ratio of 1:3.8-4.2:3.8-4.2, and then the pH value is adjusted to 1-2 with concentrated hydrochloric acid. At 30-40 °C, it is stirred at 280-320 r / min for 25-40 min to obtain the silica sol.

[0022] Further, the catalyst is at least one of dibutyltin dilaurate and stannous octoate. The addition amount of the catalyst is 0.03-0.05% of the total mass of the diol, 1-(furan-2-yl)-neopentane-1,3-diol, methyl ethyl ketoxime and isophorone diisocyanate.

[0023] Further, the TPU foam film further includes a TPU hot melt adhesive film and a non-woven fabric, and the TPU hot melt adhesive film and the non-woven fabric are sequentially laminated on the lower surface of the TPU foam layer from top to bottom.

[0024] Further, the thickness of the TPU hot melt adhesive film is 0.08-0.1 cm, and the thickness of the non-woven fabric is 0.2-0.4 cm.

[0025] The present invention also provides a preparation method of the TPU foam film with unchanged three-dimensional texture after multiple hot presses, including the following steps:

[0026] S1. Take the TPU foam layer, engrave grooves on the upper surface of the TPU foam layer with an ultraviolet laser engraving machine, then put it into a treatment chamber and introduce nitrogen, and use a plasma device to perform plasma surface activation on the upper surface of the TPU foam layer.

[0027] S2. Under nitrogen protection, apply a composite PU coating on the upper surface of the TPU foam layer that has been activated to form a composite PU layer. Use a mold to hot press the composite PU layer at a temperature of 130-150 °C for 30-60 s and then quickly cool it to room temperature, and the pressure is 12-17 Mpa, so that the upper surface of the composite PU layer forms uneven textures to form a texture layer;

[0028] S3. Take a TPU hot melt adhesive film and a non-woven fabric, and successively laminate the TPU hot melt adhesive film and the non-woven fabric onto the lower surface of the TPU foam layer from top to bottom. Use a mold to thermally press it at a temperature of 90 - 110 °C for 10 - 30 s and then quickly cool it to room temperature, with a pressure of 0.5 - 1 Mpa, so that the TPU hot melt adhesive film melts to firmly bond the TPU foam layer and the non-woven fabric together to obtain a TPU foam film.

[0029] Further, in step S1, the ultraviolet light wavelength used by the ultraviolet laser engraving machine is 350 - 360 nm, the plasma treatment power is 80 - 130 W, the pressure is 10 - 50 Pa, and the treatment time is 90 - 150 s.

[0030] Further, the TPU foam layer uses a TPU foam film of model ZD - 85A from Guangdong Zhongding Technology Development Co., Ltd., with a thickness of 0.4 - 1.2 cm and a density of 0.3 g / cm 3 。

[0031] Further, the texture layer does not deform after hot pressing.

[0032] The preparation method of the TPU foam film of the present invention has a simple process and easy operation control, which is conducive to large-scale industrial production. The prepared TPU foam film has stable quality, and the three-dimensional texture of the texture layer does not deform after multiple hot pressings, that is, the texture layer has excellent wear resistance, and at the same time, it also has good adhesion, aging resistance and heat resistance, so that the TPU foam film has excellent wear resistance, and at the same time, it also has good aging resistance and excellent heat resistance, and the comprehensive performance is superior.

[0033] The beneficial effects of the present invention are as follows: the structure of the TPU foam film with three-dimensional textures that are not deformed after multiple hot pressing is ingenious, a groove with an inverted trapezoidal cross section is provided on the surface of the TPU foam layer, and an insert block extends into the groove at the lower end of the texture layer, so that the composite PU coating penetrates into the groove and solidifies into the insert block, and the groove and the insert block form a "rivet" type mechanical locking structure to enhance mechanical interlocking, so that the TPU foam layer and the texture layer are firmly connected, and the TPU foam layer and the texture layer are prevented from being delaminated after two hot pressings in the production process, and the texture layer is coated with a composite PU coating, and the three-dimensional texture of the texture layer is not deformed after multiple hot pressing, so that the texture layer has excellent wear resistance, and also has good adhesion, aging resistance and heat resistance, which can highlight the three-dimensional sense of the product, and at the same time, the TPU foam layer helps to improve the film layer's good elasticity and impact resistance and other properties, so that the obtained TPU foam film with three-dimensional textures that are not deformed after multiple hot pressing has stable quality, good fixed form, and excellent stability in appearance, and has excellent wear resistance, aging resistance and heat resistance. The preparation method of TPU foam film has simple process, easy controllable operation, low defect rate, high output, good economic effect, and is conducive to large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic structural diagram of Embodiment 1 of the present invention;

[0035] Figure 2 is a schematic diagram of the decomposed structure of Embodiment 1 of the present invention;

[0036] Figure 3 It is a schematic diagram of the decomposition structure of Example 2 of the present invention.

[0037] The accompanying drawings are marked as follows:

[0038] 1. Texture layer; 2. TPU foam layer; 3. Groove; 4. Insert; 5. TPU hot melt adhesive film; 6. Non-woven fabric. DETAILED DESCRIPTION

[0039] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0040] Example 1

[0041] In the present embodiment, a TPU foam film having three-dimensional textures that does not deform after multiple hot pressings includes a texture layer and a TPU foam layer. The texture layer is arranged on the upper surface of the TPU foam layer. The upper surface of the TPU foam layer is provided with a plurality of grooves, and the plurality of grooves are distributed in a matrix. The cross-section of the groove is an inverted trapezoid. An insert block extends from the lower end of the texture layer into the groove, and the insert block is snap-fitted into the groove.

[0042] Further, the groove depth of the groove is 30 μm, the distance between two adjacent grooves is 100 μm, wherein the top width of the cross-section of the groove is 50 μm and the bottom width is 30 μm.

[0043] Further, the thickness of the texture layer is 90 μm; the thickness of the TPU foam layer is 0.5 cm.

[0044] The TPU foam film with non-deformed three-dimensional texture after multiple hot presses of the present invention has a clever structure. On the surface of the TPU foam layer, there are grooves with an inverted trapezoidal cross-section. The lower end of the texture layer extends into the groove with an insert block, so that the composite PU coating penetrates into the groove and cures into the insert block. The groove and the insert block form a "rivet"-type mechanical locking structure, enhancing mechanical interlocking, making the connection between the TPU foam layer and the texture layer firm, avoiding delamination between the TPU foam layer and the texture layer after two hot presses in the production process, and the three-dimensional texture of the texture layer remains non-deformed and clearly distinguishable after multiple hot presses. While the texture layer has excellent adhesion, it also has a good fixed shape, excellent stability, as well as excellent heat resistance and flexural resistance, and can highlight the three-dimensional sense and texture clarity of the product surface.

[0045] Example 2

[0046] In this embodiment, a TPU foam film with non-deformed three-dimensional texture after multiple hot presses includes a texture layer, a TPU foam layer, a TPU hot melt adhesive film, and a non-woven fabric arranged in sequence from top to bottom. The texture layer is disposed on the upper surface of the TPU foam layer. The upper surface of the TPU foam layer is provided with a plurality of grooves, and the plurality of grooves are distributed in a matrix. The cross-section of the groove is an inverted trapezoid. The lower end of the texture layer extends into the groove with an insert block, and the insert block is clamped with the groove.

[0047] Further, the groove depth of the groove is 30 μm, the distance between two adjacent grooves is 100 μm, wherein the top width of the cross-section of the groove is 50 μm and the bottom width is 30 μm.

[0048] Further, the thickness of the texture layer is 90 μm; the thickness of the TPU foam layer is 0.5 cm, the thickness of the TPU hot melt adhesive film is 0.08 cm, and the thickness of the non-woven fabric is 0.2 cm.

[0049] Example 3

[0050] In this embodiment, the texture layer is coated with a composite PU coating, and the preparation method of the composite PU coating includes the following steps:

[0051] A1. Place the diol in a reaction vessel, stir and heat up to 120 °C, control the pressure in the reaction vessel at -0.04 MPa for dehydration; then fill with nitrogen, cool down to 80 °C, add isophorone diisocyanate and a catalyst, carry out a catalytic reaction for 3 h, then cool down to 70 °C, add 1-(furan-2-yl)-neopentane-1,3-diol for a chain extension reaction for 1.5 h, and then add methyl ethyl ketoxime for a capping reaction for 1.5 h. After the reaction is completed, mixture one is obtained.

[0052] A2. Raise the temperature to 75 °C, add silica sol and alumina nanoparticles to mixture one, stir evenly and carry out ultrasonic treatment for 1.5 h to obtain mixture two.

[0053] A3. Cool down to room temperature, add bismaleimide and epoxy resin to mixture two and stir evenly to obtain the composite PU coating.

[0054] Further, the molar ratio of the diol, 1-(furan-2-yl)-neopentane-1,3-diol, methyl ethyl ketoxime to isophorone diisocyanate is 1:0.6:0.4:1.8.

[0055] Further, the diol is polycaprolactone diol 1000.

[0056] Further, the molar ratio of bismaleimide to 1-(furan-2-yl)-neopentane-1,3-diol is 1:2.3.

[0057] Further, the addition amount of the epoxy resin is 20% of the total mass of the diol, 1-(furan-2-yl)-neopentane-1,3-diol, methyl ethyl ketoxime and isophorone diisocyanate.

[0058] Further, the epoxy resin uses bisphenol A epoxy resin with an epoxy value of 0.46 from Shanghai Complex High-Tech Materials Co., Ltd.

[0059] Further, the total addition amount of the silica sol and alumina nanoparticles is 14% of the total mass of the diol, 1-(furan-2-yl)-neopentane-1,3-diol, methyl ethyl ketoxime and isophorone diisocyanate, and the mass ratio of the silica sol to the alumina nanoparticles is 1:0.6.

[0060] Further, the particle size of the alumina nanoparticles is 50 nm.

[0061] Further, the preparation method of the silica sol includes the following steps: Prepare tetraethyl orthosilicate, deionized water and absolute ethanol according to a molar ratio of 1:4:4, and then adjust the pH value to 1.5 with concentrated hydrochloric acid. Stir at 300 r / min at 35 °C for 30 min to obtain the silica sol.

[0062] Furthermore, the catalyst is dibutyltin dilaurate. The addition amount of the catalyst is 0.04% of the total mass of diol, 1-(furan-2-yl)-neopentane-1,3-diol, methyl ethyl ketoxime and isophorone diisocyanate.

[0063] The present invention also provides a method for preparing the TPU foamed film with unchanged three-dimensional texture after multiple hot presses, including the following steps:

[0064] S1. Take the TPU foamed layer, engrave grooves on the upper surface of the TPU foamed layer by using an ultraviolet laser engraving machine, then put it into a treatment chamber and introduce nitrogen, and use a plasma device to perform plasma surface activation on the upper surface of the TPU foamed layer.

[0065] S2. Under the protection of nitrogen, coat the composite PU coating on the upper surface of the TPU foamed layer after activation treatment to form a composite PU layer, use a mold to hot press the composite PU layer at a temperature of 140°C for 50 s and then quickly cool it to room temperature, and the pressure is 15 Mpa, so that uneven textures are formed on the upper surface of the composite PU layer to form a texture layer;

[0066] S3. Take the TPU hot melt adhesive film and non-woven fabric, laminate the TPU hot melt adhesive film and non-woven fabric on the lower surface of the TPU foamed layer from top to bottom in sequence, use a mold to hot press it at a temperature of 100°C for 20 s and then quickly cool it to room temperature, and the pressure is 0.7 Mpa, so that the TPU hot melt adhesive film melts to firmly laminate the TPU foamed layer and the non-woven fabric together to obtain the TPU foamed film.

[0067] Furthermore, in step S1, the ultraviolet light wavelength used by the ultraviolet laser engraving machine is 355 nm, the plasma treatment power is 100 W, the pressure is 40 Pa, and the treatment time is 120 s.

[0068] Furthermore, the TPU foamed layer uses a TPU foamed film with the model of ZD-85A produced by Guangdong Zhongding Technology Development Co., Ltd., the thickness is 0.5 cm, and the density is 0.3 g / cm 3 .

[0069] The remaining content of this embodiment is the same as that of Embodiment 2.

[0070] Embodiment 4

[0071] In this embodiment, the preparation method of the composite PU coating includes the following steps:

[0072] A1. Place the diol in a reaction vessel, stir and heat up to 120 °C, control the pressure in the reaction vessel at -0.04 MPa for dehydration; then fill with nitrogen, cool down to 80 °C, add isophorone diisocyanate and a catalyst, carry out a catalytic reaction for 3 h, then cool down to 70 °C, add 1-(furan-2-yl)-neopentane-1,3-diol for a chain extension reaction for 1.5 h, and then add methyl ethyl ketoxime for a capping reaction for 1.5 h. After the reaction is completed, mixture one is obtained.

[0073] A2. Raise the temperature to 75 °C, add silica sol and alumina nanoparticles to mixture one, stir evenly and carry out ultrasonic treatment for 1.5 h to obtain mixture two.

[0074] A3. Cool down to room temperature, add bismaleimide and epoxy resin to mixture two and stir evenly to obtain the composite PU coating.

[0075] Further, the diol is polytetrahydrofuran diol 1000.

[0076] The present invention also provides a preparation method of the TPU foamed film with unchanged three-dimensional texture after multiple hot presses, including the following steps:

[0077] S1. Take the TPU foamed layer, engrave grooves on the upper surface of the TPU foamed layer by using an ultraviolet laser engraving machine, then put it into a treatment chamber and introduce nitrogen, and perform plasma surface activation on the upper surface of the TPU foamed layer by using a plasma device.

[0078] S2. Under nitrogen protection, coat the composite PU coating on the upper surface of the TPU foamed layer that has been activated to form a composite PU layer. Use a mold to hot press the composite PU layer at a temperature of 140 °C for 50 s and then quickly cool down to room temperature, with a pressure of 15 Mpa, so that the upper surface of the composite PU layer forms uneven textures to form a texture layer.

[0079] S3. Take the TPU hot melt adhesive film and non-woven fabric, laminate the TPU hot melt adhesive film and non-woven fabric on the lower surface of the TPU foamed layer in sequence from top to bottom. Use a mold to hot press it at a temperature of 100 °C for 20 s and then quickly cool down to room temperature, with a pressure of 0.7 Mpa, so that the TPU hot melt adhesive film melts to firmly laminate the TPU foamed layer and the non-woven fabric together to obtain the TPU foamed film.

[0080] The remaining content of this example is the same as that of Example 3.

[0081] Example 5

[0082] In this example, the preparation method of the composite PU coating includes the following steps:

[0083] A1. Place the diol in a reaction vessel, stir and heat up to 120 °C, control the pressure in the reaction vessel at -0.04 MPa for dehydration; then fill with nitrogen, cool down to 80 °C, add isophorone diisocyanate and a catalyst, carry out a catalytic reaction for 3 h, then cool down to 70 °C, add 1-(furan-2-yl)-neopentane-1,3-diol for a chain extension reaction for 1.5 h, and then add methyl ethyl ketoxime for a capping reaction for 1.5 h. After the reaction is completed, mixture one is obtained;

[0084] A2. Raise the temperature to 75 °C, add silica sol and alumina nanoparticles to mixture one, stir evenly and carry out ultrasonic treatment for 1.5 h to obtain mixture two;

[0085] A3. Cool down to room temperature, add bismaleimide and epoxy resin to mixture two and stir evenly to obtain the composite PU coating.

[0086] Further, the diol is polypropylene glycol 1000.

[0087] The present invention also provides a preparation method of the TPU foamed film with unchanged three-dimensional texture after multiple hot presses, including the following steps:

[0088] S1. Take the TPU foamed layer, engrave grooves on the upper surface of the TPU foamed layer using an ultraviolet laser engraving machine, then put it into a treatment chamber and introduce nitrogen, and use a plasma device to perform plasma surface activation on the upper surface of the TPU foamed layer.

[0089] S2. Under nitrogen protection, coat the composite PU coating on the upper surface of the TPU foamed layer that has been activated to form a composite PU layer. Use a mold to hot press the composite PU layer at a temperature of 140 °C for 50 s and then quickly cool down to room temperature, with a pressure of 15 Mpa, so that the upper surface of the composite PU layer forms uneven textures to form a texture layer;

[0090] S3. Take the TPU hot melt adhesive film and non-woven fabric, laminate the TPU hot melt adhesive film and non-woven fabric on the lower surface of the TPU foamed layer in sequence from top to bottom. Use a mold to hot press it at a temperature of 100 °C for 20 s and then quickly cool down to room temperature, with a pressure of 0.7 Mpa, so that the TPU hot melt adhesive film melts to firmly laminate the TPU foamed layer and the non-woven fabric together to obtain the TPU foamed film.

[0091] The remaining content of this example is the same as that of Example 3.

[0092] Comparative Example 1

[0093] The difference between this comparative example and Example 3 is that in the preparation method of the composite PU coating, epoxy resin is not added.

[0094] Comparative Example 2

[0095] The difference between this comparative example and Example 3 lies in that: in the preparation method of the composite PU coating, an equal amount of silica is used to replace silica sol, and the particle size of the silica is 60 nm.

[0096] Comparative Example 3

[0097] The difference between this comparative example and Example 3 lies in that: in the preparation method of the composite PU coating, an equal amount of silica sol is used to replace alumina nanoparticles.

[0098] Performance Test

[0099] Performance tests were carried out on the TPU foamed films with unchanged three-dimensional patterns after multiple hot presses prepared in Example 2 and Comparative Examples 1-2. The abrasion resistance of the texture layer, the adhesion on the surface of the TPU foamed layer under different conditions, and the heat resistance were tested. The test data are shown in Table 1 below:

[0100] Table 1

[0101]

[0102]

[0103] Among them, for the abrasion resistance test: the TPU foamed film was cut into the shape specified in GB / T 1768-2006 and placed on a TABER abrasion tester (GT-7012-T) to observe the surface change of the texture layer during friction. The type of grinding wheel was CS-10, the set rotation speed was 72 r / min, and the surface load weight was 1000 g. The exposed bottom in Table 1 refers to the exposure of the bottom surface, that is, the wear of the texture layer, and the TPU foamed layer can be seen;

[0104] The adhesion test was carried out according to GB / T 9286-1998;

[0105] The aging resistance test was carried out by treating with QUV 340 nm for 1000 hours, and the light intensity was 0.8 W / cm 2 ;

[0106] The heat resistance test was carried out according to ISO 25178. After the texture layer was hot-pressed 5 times at 100 °C / 3 min, a laser confocal microscope was used to detect and observe the height deviation of the pattern.

[0107] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention can also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A TPU foam film with unchanged three-dimensional texture after multiple hot presses, characterized in that: It includes a texture layer and a TPU foam layer. The texture layer is disposed on the upper surface of the TPU foam layer. Multiple grooves are formed on the upper surface of the TPU foam layer, and the multiple grooves are distributed in a matrix. The cross-section of the groove is an inverted trapezoid. An insertion block extends from the lower end of the texture layer into the groove, and the insertion block is snap-fitted with the groove.

2. The TPU foamed film with unchanged three-dimensional texture after multiple hot presses according to claim 1, wherein: The depth of the groove is 25-35μm, and the distance between two adjacent grooves is 95-105μm.

3. The TPU foamed film with unchanged three-dimensional texture after multiple hot presses according to claim 1, wherein: The texture layer is coated with a composite PU coating, and the preparation method of the composite PU coating includes the following steps: A1. Place the diol in a reaction vessel, stir and heat up to 115-130°C, control the pressure in the reaction vessel to be -0.02-0.06MPa, and dehydrate; then fill with nitrogen, cool down to 75-85°C, add isophorone diisocyanate and a catalyst, catalyze the reaction for 1-3h, then cool down to 65-75°C, add 1-(furan-2-yl)-neopentane-1,3-diol for chain extension reaction for 1-2h, and then add methyl ethyl ketoxime for capping reaction for 1-2h. After the reaction is completed, mixture one is obtained; A2. Raise the temperature to 70-80°C, add silica sol and alumina nanoparticles to mixture one, stir evenly and perform ultrasonic treatment for 1-2h to obtain mixture two; A3. Cool down to room temperature, add bismaleimide and epoxy resin to mixture two, and stir evenly to obtain the composite PU coating.

4. The TPU foamed film with unchanged three-dimensional texture after multiple hot presses according to claim 3, wherein: The molar ratio of the diol, 1-(furan-2-yl)-neopentane-1,3-diol, methyl ethyl ketoxime to isophorone diisocyanate is 1:0.4-0.8:0.2-0.6:1-2.

5. The TPU foamed film with unchanged three-dimensional texture after multiple hot presses according to claim 3, characterized in that: The molar ratio of the bismaleimide to 1-(furan-2-yl)-neopentane-1,3-diol is 1:2.2-2.

5.

6. The TPU foamed film with unchanged three-dimensional texture after multiple hot presses according to claim 3, wherein: The addition amount of the epoxy resin is 15-25% of the total mass of the diol, 1-(furan-2-yl)-neopentane-1,3-diol, methyl ethyl ketoxime and isophorone diisocyanate.

7. The TPU foamed film with unchanged three-dimensional texture after multiple hot pressing according to claim 3, wherein: The total addition amount of the silica sol and alumina nanoparticles is 8-16% of the total mass of the diol, 1-(furan-2-yl)-neopentane-1,3-diol, methyl ethyl ketoxime and isophorone diisocyanate, and the mass ratio of the silica sol to the alumina nanoparticles is 1:0.3-0.

7.

8. The TPU foamed film with unchanged three-dimensional texture after multiple hot presses according to claim 3, characterized in that: The diol is at least one of polycaprolactone diol, polytetrahydrofuran diol and polyoxypropylene diol.

9. The TPU foamed film with unchanged three-dimensional texture after multiple hot presses according to claim 3, characterized in that: The catalyst is at least one of dibutyltin dilaurate and stannous octoate.

10. A method for preparing a TPU foamed film with unchanged three-dimensional texture after multiple hot presses according to any one of claims 1-9, characterized in that: It includes the following steps: S1. Take the TPU foam layer, engrave grooves on the upper surface of the TPU foam layer using an ultraviolet laser engraving machine, then put it into a treatment chamber and introduce nitrogen, and use a plasma device to perform plasma surface activation on the upper surface of the TPU foam layer. S2. Under nitrogen protection, a composite PU coating is applied to the upper surface of the activated TPU foaming layer to form a composite PU layer. The composite PU layer is hot-pressed with a mold at a temperature of 130-150° C. for 30-60 seconds and then rapidly cooled to room temperature at a pressure of 12-17 MPa, so that uneven textures are formed on the upper surface of the composite PU layer to form a texture layer. S3. Take TPU hot-melt adhesive film and non-woven fabric, and adhere the TPU hot-melt adhesive film and non-woven fabric to the lower surface of the TPU foam layer from top to bottom in sequence. Use a mold to hot-press them at a temperature of 90-110°C for 10-30s and then quickly cool them to room temperature at a pressure of 0.5-1Mpa, so that the TPU hot-melt adhesive film is hot-melted to firmly adhere the TPU foam layer and the non-woven fabric together to obtain a TPU foam film.

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