Colorful TPO interior foot pad skin and preparation method thereof

Abstract

The invention discloses a colorful TPO interior foot pad skin and a preparation method thereof, and relates to the technical field of automobile interiors. The surface functional layer is used for improving wear resistance, the colorful pattern layer is used for presenting a visual effect, and one surface, far away from the base material layer, of the bottom layer structure is of a 3D net-shaped structure; the surface functional layer comprises matte water-based PUD resin, matte water-based PUA resin, a wear-resistant additive, a cross-linking agent and a diluent; the colorful pattern layer comprises water-based or solvent-based poly-carbon type polyurethane resin, water-based or solvent-based color paste and auxiliaries; the base material layer comprises modified TPO resin, nano calcium carbonate, a light stabilizing aid and a pigment; the bottom layer structure comprises modified TPE, an AC foaming agent and a DCP cross-linking agent; through the innovation of the composite structure, the colorful pattern layer design, the environment-friendly TPO base material, the net-shaped bottom layer structure and the like, on the basis of meeting functional requirements, light weight and personalized upgrading of the foot pad skin are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive interior decoration, and specifically relates to a colorful TPO interior foot mat skin and a preparation method thereof. Background Art

[0002] Leather foot mats are an indispensable part of today's automotive interiors, which can provide vehicle users with improved driving experiences in terms of anti-slip, sound insulation and shock absorption, aesthetics, dirt resistance, etc.

[0003] At present, the PVC foot mat leather commonly used in the market has problems such as plasticizer migration, low-temperature embrittlement, difficult recycling, strong odor, and poor emission performance. Therefore, the industry is trying to use other materials to replace PVC foot mat leather.

[0004] The invention patent with the publication number CN118185327B and the name of a wear-resistant matte TPE foot mat and a preparation method thereof discloses improving the wear resistance of the TPE foot mat by modified molybdenum disulfide and filling the material gaps with modified vermiculite to improve the compactness and mechanical properties of the foot mat. However, there are certain defects in the wear resistance and heat resistance of the TPE material. Even if it is improved to a certain extent through additives, there are still differences compared with materials with more excellent inherent properties. If a partial replacement method is adopted to combine TPE and PVC, although the mechanical properties can be improved in other aspects, not only the defects of the PVC material cannot be completely solved, but also the two materials need to be glued with glue, bringing other non-environmental factors. And the combination of TPE and PVC is exactly a very common material for automotive interior foot mats on the market.

[0005] In addition, traditional foot mats have a large density and a single surface color and pattern, which are difficult to meet the increasing pursuit of people for the lightweight and personalization of foot mats. Summary of the Invention

[0006] The TPO material has the characteristics of lightweight, low odor, low VOC content, and excellent heat resistance, light resistance and low-temperature resistance. This material is more environmentally friendly than PVC. Although the TPO has higher strength than TPE, compared with PVC, the surface hardness of the TPO material is still insufficient, and it is easily worn, resulting in a short service life. Moreover, it is difficult for the TPO material to balance anti-slip performance, stain resistance and touch comfort. In summary, the purpose of the present invention is to provide a colorful TPO interior foot mat skin and a preparation method thereof to manufacture an interior foot mat skin that better meets the market demand.

[0007] To achieve the above purpose, the present invention provides the following technical solution: A colorful TPO interior foot mat skin, which is sequentially composed of a surface functional layer, a colorful pattern layer, a base material layer, and a bottom structure from outside to inside, wherein the surface functional layer is used to improve the wear resistance, the colorful pattern layer is used to present a visual effect, and one side of the bottom structure away from the base material layer is a 3D mesh structure; The components of the surface functional layer are counted by weight parts and include 40-80 parts of matte waterborne PUD resin, 5-20 parts of matte waterborne PUA resin, 1-10 parts of wear-resistant additive, 5-8 parts of crosslinking agent, and 0-30 parts of diluent; The components of the colorful pattern layer are counted by weight parts and include 80-95 parts of waterborne or solvent-based polyurethane resin of polycarbon type, 3-10 parts of waterborne or solvent-based color paste, and 0-2 parts of additive; The components of the substrate layer are counted by weight parts and include 80-95 parts of modified TPO resin, 5-10 parts of nano calcium carbonate, 0.1-4 parts of light stabilizer additive, and 2-4 parts of pigment; The components of the bottom layer structure are counted by weight parts and include 90-95 parts of modified TPE, 1-4 parts of AC blowing agent, and 1-4 parts of DCP crosslinking agent.

[0008] Preferably, the components of the modified TPO resin in the substrate layer are counted by weight parts and include 20-60 parts of TPV particles, 10-30 parts of LLDPE particles, 10-30 parts of PP particles, and 5-20 parts of POE particles.

[0009] Preferably, the components of the modified TPE in the bottom layer structure are counted by weight parts and include 30-70 parts of SEBS particles, 10-20 parts of PP particles, 20-40 parts of halogen-free flame retardant, and 5-20 parts of white oil.

[0010] Preferably, in the surface functional layer, the matte waterborne PUD resin is of waterborne polyurethane type with a solid content of 25-40%; the matte waterborne PUA resin is of waterborne polyurethane acrylate type with a solid content of 25-35%; the wear-resistant additive is of ultra-high molecular weight polysiloxane dispersion with a solid content of 60-85%; the crosslinking agent is of polycarbodiimide crosslinking agent; the diluent is of distilled water.

[0011] Preferably, when adding additives to the colorful pattern layer, one or two of dispersant and leveling agent are used.

[0012] Preferably, the thickness of the substrate layer is 0.4-0.8 mm; the density of the bottom layer structure is 0.3-0.6 g / cm 3 and the thickness is 1.0-2.5 mm.

[0013] Another technical solution provided by the present invention: A preparation method of a colorful TPO interior foot mat skin, comprising the following steps: Step 1: The substrate layer and the bottom layer structure are co-extruded in multiple layers. According to the proportion, the raw materials of the substrate layer components and the raw materials of the bottom layer structure components enter the extruder through the automatic feeding system, and a cast film is extruded through a double-layer co-extrusion twin-screw extruder; the substrate layer is on the top, the bottom layer structure is on the bottom and the gap and pressure foaming are adjusted according to process requirements; Step 2: The bottom surface of the cast film passes through a patterned back roll with a 3D mesh structure and is extruded and cooled to form a bottom 3D mesh structure; Step 3: The semi-finished substrate layer in Step 2 is evenly coated with the colored pattern layer slurry of adjusted color by using a screen roller with different patterns through the printing and patterning process of the printing machine, and a colored pattern layer is formed after heat treatment; Step 4: The surface functional layer slurry is evenly coated on the surface of the semi-finished colored pattern layer made in Step 3 by a finishing machine, and a surface functional layer is formed after heat treatment.

[0014] Preferably, the temperature of the multi-layer co-extrusion in Step 1 is controlled at 160 - 210 °C, the back roll gap is set at 60% - 70% of the total product thickness, the back roll pressure is 5 ± 1 MPa, and the heat treatments in Steps 3 and 4 are heating at 100 - 130 °C for 2 - 3 min respectively.

[0015] Preferably, before feeding the printing machine in Step 3, online surface corona plasma treatment is first carried out to enhance the interfacial bonding strength between the colored pattern layer and the substrate layer.

[0016] Preferably, the power of the online surface corona plasma treatment is 1.4 - 3.5 kw.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. The skin of the colorful TPO interior foot mat uses recyclable TPO, which is more environmentally friendly, as the substrate, and the bottom layer structure uses foamed TPE, which can provide a soft texture and shock absorption effect. The two are thermally bonded in one step. The present invention takes into account the lightweight design through material selection and the mesh structure of the bottom layer structure. The mesh structure also improves the anti-slip performance. The adopted composite multi-layer structure realizes the gradient distribution of functions and improves the wear resistance of the surface, meeting the user's demand for the high-class feeling of automotive interior foot mats.

[0018] 2. The skin of the colorful TPO interior foot mat innovatively designs a colored pattern layer, which does not affect the functions of the TPO layer and the surface functional layer. On the basis of meeting the performance requirements of the interior foot mat skin such as wear resistance, weather resistance, flame retardancy, and low odor, the colored pattern layer can further meet the personalized and technological feeling requirements of automotive interiors, getting rid of the disadvantages of the traditional foot mat leather with a single color and no pattern on the surface.

[0019] 3. The preparation method of the skin of the colorful TPO interior foot mat generally requires less adjustment of the equipment and process on the basis of the existing process. The method is simple and easy to operate, the implementation cost is low, it is easy to directly implement improvements on the existing basis, and the applicable range is wide. Description of the Drawings

[0020] Figure 1 It is a schematic diagram of the positional relationship of the layered structure of the present invention.

[0021] In the figure: 1. Surface functional layer; 2. Colorful pattern layer; 3. Base material layer; 4. Bottom structure. DETAILED DESCRIPTION

[0022] In order to prepare a car mat that can meet the growing needs of users in more aspects, the present invention designs a colorful TPO interior mat surface, see Figure 1 , which is composed of a surface functional layer, a colorful pattern layer, a substrate layer, and a bottom structure from the outside to the inside. This composite structure can achieve a functional gradient distribution. The surface functional layer can improve the wear resistance while taking into account the anti-slip property, the stain resistance and the tactile comfort. The colorful pattern layer can present a visual effect, such as a colorful pattern, etc. The innovative design of this layer can meet the needs of personalized and technological sense of automobile interior decoration, get rid of the shortcomings of the traditional foot pad leather with a single color and no pattern on the surface, and is well integrated into the multi-layer structure of the interior foot pad of the present invention, and will not interfere with the adjacent layer materials. The substrate layer uses TPO material as the main material, which is environmentally friendly and recyclable and can meet the requirements of ELV regulations. The bottom structure is 3D mesh structure on the side away from the substrate layer, which can reduce shock and prevent slipping. At the same time, the mesh is conducive to lightweight. The substrate layer can also play a role in supporting the transition between the 3D mesh structure and the colorful pattern layer. The specific raw material components of each layer are as follows: The components of the surface functional layer are calculated by weight, including 40-80 parts of matte water-based PUD resin, 5-20 parts of matte water-based PUA resin, 1-10 parts of wear-resistant additive, 5-8 parts of cross-linking agent, and 0-30 parts of diluent; The components of the colorful pattern layer are calculated by weight, including 80-95 parts of water-based or solvent-based polycarbonate type polyurethane resin, 3-10 parts of water-based or solvent-based color paste, and 0-2 parts of auxiliary agent. Further preferably, the auxiliary agent is one or two of a dispersant and a leveling agent, which are mainly selected and added according to the color requirements of the pattern; The components of the substrate layer are calculated by weight, including 80-95 parts of modified TPO resin, 5-10 parts of nano calcium carbonate, 0.1-4 parts of light stabilizing agent, and 2-4 parts of pigment; The components of the bottom structure are calculated by weight, including 90-95 parts of modified TPE, 1-4 parts of AC foaming agent, and 1-4 parts of DCP cross-linking agent.

[0023] In a preferred embodiment, the components of the modified TPO resin in the substrate layer include, by weight, 20-60 parts of TPV particles, 10-30 parts of LLDPE particles, 10-30 parts of PP particles, and 5-20 parts of POE particles.

[0024] In a preferred embodiment, the components of the modified TPE in the bottom layer structure include, by weight, 30-70 parts of SEBS particles, 10-20 parts of PP particles, 20-40 parts of halogen-free flame retardant, and 5-20 parts of white oil.

[0025] In a preferred embodiment, in the surface functional layer, the matte water-based PUD resin adopts water-based polyurethane with a solid content of 25-40%; the matte water-based PUA resin adopts water-based polyurethane acrylate with a solid content of 25-35%; the wear-resistant additive adopts ultra-high molecular weight polysiloxane dispersion with a solid content of 60-85%; the cross-linking agent adopts polycarbodiimide cross-linking agent; and the diluent adopts distilled water.

[0026] The selection of the above raw materials can also refer to the following examples.

[0027] In order to better achieve the effect of the above-mentioned multi-layer structure, for reference, the thickness of the substrate layer can be controlled at 0.4-0.8mm to provide sufficient support; the density of the bottom layer structure should be 0.3-0.6 g / cm 3 , the thickness can be controlled at 1.0-2.5mm; The specific preparation method of the interior trim foot pad surface of the present invention can refer to the following steps: Step 1: The substrate layer and the bottom structure adopt a multi-layer co-extrusion process. The raw materials of the substrate layer components and the raw materials of the bottom structure components are fed into the extruder through an automatic feeding system according to the proportion, and the cast film is extruded through a double-layer co-extrusion twin-screw extruder. When adding the raw materials, the four components of the modified TPO resin and the modified TPE are added to the extruders corresponding to each layer respectively, without separate preparation; the substrate layer is on the top, the bottom structure is on the bottom, and the gap and pressure foaming are adjusted according to the process requirements; for reference, the temperature of multi-layer co-extrusion can be controlled at 160-210°C, the back roller gap is set at 60%-70% of the total thickness of the product, and the back roller pressure can be 5±1MPa; Step 2: The bottom structure surface of the cast film passes through a patterned back roller with a 3D mesh structure, and is extruded and cooled to form a bottom 3D mesh structure, which can play a role in laminating and anti-slip; Step 3: The semi-finished substrate layer in step 2 is subjected to the overlay process of the printing machine (synthetic leather surface printing machine), and the colorful pattern layer slurry with adjusted colors is evenly coated with mesh rollers of different patterns, and a colorful pattern layer is formed after heat treatment. The heat treatment condition can be heated at 100-130℃ for 2-3min; in addition, before the printing machine is loaded, online surface corona plasma treatment can be used first, and the power can be further selected to be 1.4-3.5kw. This treatment can further improve the interlayer bonding strength between the colorful pattern and the substrate layer (the specific interlayer bonding strength improvement result can refer to the peeling force ≥25 N / cm); Step 4: Uniformly apply the surface functional layer slurry on the surface of the semi-finished colorful pattern layer made in Step 3 through a finishing machine, and form the surface functional layer after heat treatment. The heat treatment conditions can be heating at 100-130°C for 2-3 minutes.

[0028] In the following examples, the raw materials of the surface functional layer are selected as follows: the matte water-based PUD resin is Sloko 3247, the matte water-based PUA resin is Sloko 1951, the wear-resistant additive is Sloko 5289, and the cross-linking agent is Sloko ET-558; since the colorful pattern layer does not provide performance effects, the raw materials do not need to be specially selected; in the modified TPO resin of the substrate layer, the TPV particles are ExxonMobil TPV 8281, the LLDPE particles are Dow LLDPE 2607G, the PP particles are ExxonMobil PP 4772, and the POE particles are Dow POE 58705; in the modified TPE of the bottom layer structure, the SEBS particles are Elastomer G418.A60.N, and the PP particles are ExxonMobil PP 4772.

[0029] Example 1 Substrate layer formula: 90 parts of modified TPO resin (including 50 parts of TPV particles, 15 parts of LLDPE particles, 20 parts of PP particles, and 5 parts of POE particles), 6 parts of nano calcium carbonate, 2 parts of light stabilizer, 2 parts of pigment; Bottom layer structure formula: 94 parts of modified TPE (including 54 parts of SEBS particles, 10 parts of PP particles, 20 parts of halogen-free flame retardant, and 10 parts of white oil), 3 parts of AC blowing agent, 3 parts of DCP cross-linking agent; Colorful pattern layer formula: 95 parts of polyurethane resin, 3 parts of color paste, 1 part of dispersant, 1 part of leveling agent; Surface functional layer formula: 80 parts of polyurethane resin (matte water-based PUD resin: matte water-based PUA resin = 8:2), 5 parts of wear-resistant additive, 5 parts of cross-linking agent, 10 parts of distilled water; Step 1: The substrate layer and the bottom layer structure adopt a multi-layer co-extrusion process. According to the ratio, the component raw materials of the substrate layer and the component raw materials of the bottom layer structure enter the extruder through an automatic feeding system (the four components of the modified TPO resin and the modified TPE are respectively added to the corresponding extruders of each layer, and there is no need to prepare them separately), and a cast film is extruded through a double-layer co-extrusion twin-screw extruder; the substrate layer is on the top, the bottom layer structure is on the bottom, and the gap and pressure are adjusted for foaming according to the process requirements; the temperature of the multi-layer co-extrusion is 195°C, the back roll gap is set at 60% of the total product thickness, the back roll pressure is 4 MPa, the substrate layer thickness is 0.5 mm, and the foamed bottom layer thickness is 2.0 mm; Step 2: The bottom layer structure surface of the cast film passes through a patterned back roll with a 3D mesh structure and is extruded and cooled to form a bottom layer 3D mesh structure; Step 3: The semi-finished substrate layer in Step 2 is treated by online surface corona plasma with a power of 2 kw. Then, through the printing machine's pattern overlay process, using the mesh roller required for the designed pattern, the colored multi-pattern layer slurry with adjusted color is evenly coated, and after heating at 120°C for 2 min, a multi-pattern layer is formed; Step 4: The surface functional layer slurry is evenly coated on the surface of the semi-finished multi-pattern layer made in Step 3 through a finishing machine, and after heating at 120°C for 3 min, a surface functional layer is formed, obtaining the multi-color TPO interior foot mat skin.

[0030] Example 2 Base material layer formula: 85 parts of modified TPO resin (including 50 parts of TPV particles, 10 parts of LLDPE particles, 15 parts of PP particles, 10 parts of POE particles), 8 parts of nano calcium carbonate, 4 parts of light stabilizer, 3 parts of pigment; Bottom layer structure formula: 95 parts of modified TPE (including 50 parts of SEBS particles, 15 parts of PP particles, 20 parts of halogen-free flame retardant, 10 parts of white oil), 2 parts of AC blowing agent, 3 parts of DCP crosslinking agent; Multi-color pattern layer formula: 90 parts of polyurethane resin, 8 parts of color paste, 2 parts of dispersant; Surface functional layer formula: 85 parts of polyurethane resin (matte water-based PUD resin: matte water-based PUA resin = 8:2), 1 part of wear-resistant additive, 6 parts of crosslinking agent, 8 parts of distilled water; Step 1: The base material layer and the bottom layer structure adopt a multi-layer co-extrusion process. According to the ratio, the component raw materials of the base material layer and the bottom layer structure enter the extruder through an automatic feeding system (the four components of modified TPO resin and modified TPE are respectively added to the corresponding extruders of each layer, and there is no need to prepare separately), and a cast film is extruded through a double-layer co-extrusion twin-screw extruder; the base material layer is on the top, the bottom layer structure is on the bottom, and the gap and pressure for foaming are adjusted according to process requirements; the temperature of the multi-layer co-extrusion is 170°C, the back roll gap is set at 65% of the total product thickness, the back roll pressure is 5 MPa, the thickness of the base material layer is 0.6 mm, and the thickness of the foamed bottom layer is 1.5 mm; Step 2: The bottom layer structure surface of the cast film is extruded and cooled through a pattern back roll with a 3D mesh structure to form a bottom layer 3D mesh structure; Step 3: The semi-finished substrate layer in Step 2 is treated by online surface corona plasma with a power of 3 kw. Then, through the printing machine's pattern overlay process, using the mesh roller required for the designed pattern, the colored multi-pattern layer slurry with adjusted color is evenly coated, and after heating at 100°C for 3 min, a multi-pattern layer is formed; Step 4: The surface functional layer slurry is evenly coated on the surface of the semi-finished multi-pattern layer made in Step 3 through a finishing machine, and after heating at 120°C for 2 min, a surface functional layer is formed, obtaining the multi-color TPO interior foot mat skin.

[0031] Example 3 Base material layer formula: 80 parts of modified TPO resin (including 20 parts of TPV particles, 20 parts of LLDPE particles, 20 parts of PP particles, 20 parts of POE particles), 10 parts of nano calcium carbonate, 0.5 part of light stabilizer, 2 parts of pigment; Bottom layer structure formula: 90 parts of modified TPE (including 35 parts of SEBS particles, 15 parts of PP particles, 20 parts of halogen-free flame retardant, 20 parts of white oil), 4 parts of AC foaming agent, 2 parts of DCP crosslinking agent; Multicolored pattern layer formula: 80 parts of polyurethane resin, 5 parts of color paste; Surface functional layer formula: 50 parts of matte waterborne PUD resin, 10 parts of matte waterborne PUA resin, 8 parts of wear-resistant additive, 5 parts of crosslinking agent, 5 parts of distilled water; Step 1: The base material layer and the bottom layer structure adopt a multi-layer co-extrusion process. The component raw materials of the base material layer and the bottom layer structure are fed into the extruder through an automatic feeding system according to the ratio (the four components of the modified TPO resin and the modified TPE are respectively added to the corresponding extruders of each layer, and there is no need to prepare them separately), and a cast film is extruded through a double-layer co-extrusion twin-screw extruder; the base material layer is on the top, the bottom layer structure is on the bottom, and the gap and pressure are adjusted for foaming according to process requirements; the temperature of the multi-layer co-extrusion is 200 °C, the back roll gap is set at 60% of the total product thickness, the back roll pressure is 4 MPa, the thickness of the base material layer is 0.5 mm, and the thickness of the foamed bottom layer is 2 mm; Step 2: The bottom layer structure surface of the cast film passes through a pattern back roll with a 3D mesh structure, and is extruded and cooled to form a bottom layer 3D mesh structure; Step 3: The semi-finished product base material layer surface in Step 2 is treated by online surface corona plasma with a power of 3 kw, and then through the printing and pattern process, using the mesh roller required for the designed pattern, the adjusted multi-colored pattern layer slurry is evenly coated, and a multi-colored pattern layer is formed after heating at 120 °C for 2 min; Step 4: The surface functional layer slurry is evenly coated on the surface of the semi-finished multi-colored pattern layer prepared in Step 3 through a finishing machine, and a surface functional layer is formed after heating at 120 °C for 2 min, obtaining a multi-colored TPO interior foot mat skin.

[0032] Example 4 Base material layer formula: 95 parts of modified TPO resin (including 60 parts of TPV particles, 10 parts of LLDPE particles, 20 parts of PP particles, 5 parts of POE particles), 5 parts of nano calcium carbonate, 1 part of light stabilizer, 2 parts of pigment; Bottom layer structure formula: 90 parts of modified TPE (including 30 parts of SEBS particles, 10 parts of PP particles, 30 parts of halogen-free flame retardant, 20 parts of white oil), 2 parts of AC foaming agent, 2 parts of DCP crosslinking agent; Formulation of the colorful pattern layer: 90 parts of polyurethane resin, 10 parts of color paste, 1 part of dispersant, 1 part of leveling agent; Formulation of the surface functional layer: 80 parts of matte waterborne PUD resin, 20 parts of matte waterborne PUA resin, 2 parts of wear-resistant additive, 8 parts of crosslinking agent, 20 parts of distilled water; Step 1: The substrate layer and the bottom layer structure adopt a multi-layer co-extrusion process. The component raw materials of the substrate layer and the component raw materials of the bottom layer structure enter the extruder through the automatic feeding system according to the proportion (the four components of the modified TPO resin and the modified TPE are respectively added to the corresponding extruders of each layer, and there is no need for separate preparation). A cast film is extruded through a double-layer co-extrusion twin-screw extruder; the substrate layer is on the top, the bottom layer structure is on the bottom, and the gap and pressure are adjusted for foaming according to the process requirements; the temperature of the multi-layer co-extrusion is 190 °C, the back roll gap is set at 70% of the total product thickness, the back roll pressure is 6 MPa, the thickness of the substrate layer is 0.5 mm, and the thickness of the foamed bottom layer is 1.5 mm; Step 2: The bottom layer structure surface of the cast film passes through a pattern back roll with a 3D mesh structure and is extruded and cooled to form a bottom layer 3D mesh structure; Step 3: The semi-finished substrate layer surface in Step 2 is treated by online surface corona plasma with a power of 2 kw. Then, through the printing and pattern process, using the screen roller required for the designed pattern, the colorful pattern layer slurry with the adjusted color is evenly coated, and a colorful pattern layer is formed after heating at 120 °C for 2 min; Step 4: The surface functional layer slurry is evenly coated on the surface of the semi-finished colorful pattern layer prepared in Step 3 through a finishing machine, and a surface functional layer is formed after heating at 120 °C for 3 min, obtaining the skin of the colorful TPO interior foot mat.

[0033] The following methods are used for performance testing in each example, and the test results are excellent: Wear resistance QB / T 2726, Taber test, H18, 500 g, mass loss after 2000 times of wear ≤ 1%; Weather resistance GB / T 32088-2015 A-1, no cracking, powdering, stickiness, etc. after 600 h; Flame retardancy GB8410, ≤ 100 mm / min; Odor PV3900, ≤ 3.5 grades; Atomization DIN75201 Method B, ≤ 2 mg; Total carbon VDA277, ≤ 20 ugc / g.

[0034] The specific test results are shown in Table 1 below: Table 1 Test results of the examples

[0035] The above are only the preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope defined by the claims.

[0036] Those parts not detailed in the present invention are all well-known technologies to those skilled in the art.

Claims

1. A colorful TPO interior foot pad surface, characterized by: From the outside to the inside, it is composed of a surface functional layer, a colorful pattern layer, a substrate layer, and a bottom structure. The surface functional layer is used to improve the wear resistance, the colorful pattern layer is used to present the visual effect, and the bottom structure is a 3D mesh structure on the side away from the substrate layer. The components of the surface functional layer are calculated by weight, including 40-80 parts of matte water-based PUD resin, 5-20 parts of matte water-based PUA resin, 1-10 parts of wear-resistant additive, 5-8 parts of cross-linking agent, and 0-30 parts of diluent; The components of the colorful pattern layer are calculated by weight, including 80-95 parts of water-based or solvent-based polycarbonate type polyurethane resin, 3-10 parts of water-based or solvent-based color paste, and 0-2 parts of additives; The components of the substrate layer are calculated by weight, including 80-95 parts of modified TPO resin, 5-10 parts of nano calcium carbonate, 0.1-4 parts of light stabilizing agent, and 2-4 parts of pigment; The components of the bottom structure are calculated by weight, including 90-95 parts of modified TPE, 1-4 parts of AC foaming agent, and 1-4 parts of DCP cross-linking agent.

2. The colorful TPO interior foot pad surface according to claim 1, characterized in that: The components of the modified TPO resin in the substrate layer include, by weight, 20-60 parts of TPV particles, 10-30 parts of LLDPE particles, 10-30 parts of PP particles, and 5-20 parts of POE particles.

3. The colorful TPO interior foot pad surface according to claim 1, characterized in that: The components of the modified TPE in the bottom layer structure include, by weight, 30-70 parts of SEBS particles, 10-20 parts of PP particles, 20-40 parts of halogen-free flame retardant, and 5-20 parts of white oil.

4. The colorful TPO interior foot pad surface according to claim 1, characterized in that: In the surface functional layer, the matte water-based PUD resin adopts water-based polyurethane with a solid content of 25-40%; the matte water-based PUA resin adopts water-based polyurethane acrylate with a solid content of 25-35%; the wear-resistant additive adopts ultra-high molecular weight polysiloxane dispersion with a solid content of 60-85%; the cross-linking agent adopts polycarbodiimide cross-linking agent; and the diluent adopts distilled water.

5. The colorful TPO interior foot pad surface according to claim 1, characterized in that: When adding auxiliary agents to the colorful pattern layer, one or two of dispersants and leveling agents are used.

6. The colorful TPO interior foot pad surface according to claim 1, characterized in that: The thickness of the substrate layer is 0.4-0.8 mm; the density of the bottom layer structure is 0.3-0.6 g / cm 3 , thickness is 1.0-2.5mm.

7. A method for preparing the colorful TPO interior foot pad surface as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: The substrate layer and the bottom structure are co-extruded in multiple layers. The raw materials of the substrate layer components and the raw materials of the bottom structure components are fed into the extruder through an automatic feeding system according to the proportion, and the cast film is extruded through a double-layer co-extrusion twin-screw extruder; the substrate layer is on the top, and the bottom structure is on the bottom, and the gap and pressure foaming are adjusted according to the process requirements; Step 2: The bottom structure surface of the cast film passes through a patterned back roller with a 3D mesh structure, and is extruded and cooled to form a bottom 3D mesh structure; Step 3: The semi-finished substrate layer in step 2 is subjected to a printing machine overlay process, and a mesh roller with different patterns is used to evenly apply the color-adjusted colorful pattern layer slurry, and a colorful pattern layer is formed after heat treatment; Step 4: Use a finishing machine to evenly apply the surface functional layer slurry to the surface of the semi-finished colorful pattern layer made in step 3, and form a surface functional layer after heat treatment.

8. The preparation method according to claim 7, characterized in that: In step 1, the temperature of multilayer co-extrusion is controlled at 160-210° C., the back roll gap is set at 60%-70% of the total thickness of the product, the back roll pressure is 5±1 MPa, and the heat treatment in steps 3 and 4 is respectively heated at 100-130° C. for 2-3 minutes.

9. The preparation method according to claim 7, characterized in that: In the step 3, before loading the printing machine, an online surface corona plasma treatment is first performed to enhance the interlayer bonding strength between the colorful pattern layer and the substrate layer.

10. The preparation method according to claim 9, characterized in that: The power of the online surface corona plasma treatment is 1.4-3.5kw.

Images