TPO skin as well as preparation method and application thereof

Abstract

The invention provides a TPO skin and a preparation method and application thereof.The TPO skin comprises a three-layer structure including a coating, a TPO layer and a PPF layer, the TPO layer comprises a TPO surface glue layer and a TPO bottom glue layer, and the TPO bottom glue layer comprises, by weight, 50-70 parts of TPO, 10-15 parts of RTPO, 10-15 parts of LLDPE, 5-15 parts of RPP, 2-10 parts of talcum powder, 0.2-0.5 part of a lubricant, 5-10 parts of a microsphere foaming agent, 0.5-1.5 parts of nano-silica and 0.5-2.5 parts of an auxiliary. The prepared TPO white skin can meet the requirements of light weight and mechanical property at the same time, and can meet the scene requirements of the market when being used as a new energy automobile interior vacuum suction coating skin.

Description

Technical Field

[0001] This invention relates to the field of TPO epidermal production technology, and particularly to a TPO epidermal material, its preparation method, and its application. Background Technology

[0002] In the current automotive interior manufacturing sector, especially in mid-to-low-end models, polyvinyl chloride (PVC) has long been a primary material for covering dashboards, door panels, and other components due to its significant overall cost advantage. Its advantages lie not only in the low price of raw materials but also in the high production efficiency and yield rate resulting from its mature processing technologies (such as vacuum forming or slush molding). Furthermore, PVC possesses excellent plasticity and colorability, easily achieving a variety of high-quality textures from imitation leather to carbon fiber through embossing processes. It also boasts excellent surface wear and scratch resistance, meeting the core needs of OEMs for cost control and aesthetic diversity. However, as the global automotive industry undergoes a profound transformation towards the "new four modernizations" (electrification, intelligentization, connectivity, and sharing), the limitations of traditional materials are becoming increasingly apparent, and the adoption of lighter materials has become a new trend. TPO, as an advanced material more suited to the development needs of modern automobiles, especially new energy vehicles, offers significant lightweight benefits, directly contributing to the range of new energy vehicles. It is also non-toxic and environmentally friendly, making it a superior alternative to PVC in terms of overall performance. However, although TPO materials have significant advantages in terms of lightweight (lower density) compared to traditional PVC skins, and perform better in terms of VOC (volatile organic compound) control and recyclability, their own weight reduction potential has not been fully explored.

[0003] Therefore, there is an urgent need to develop a TPO material skin that can be further reduced in weight, which can be used as a vacuum-sealed skin in automotive interiors. Summary of the Invention To address the shortcomings of existing technologies, this invention proposes a TPO epidermis, its preparation method, and its application.

[0004] This invention provides a TPO skin, comprising a three-layer structure of a coating, a TPO layer, and a PPF layer. The TPO layer includes a TPO topcoat layer and a TPO basecoat layer. The TPO basecoat layer, by weight, comprises the following components: TPO (thermoplastic polyolefin elastomer) 50-70 parts, such as 50, 55, 60, 65, or 70 parts; RTPO (reactor-processed thermoplastic polyolefin) 10-15 parts, such as 10, 11, 12, 13, or 15 parts; and LLDPE (linear low-density polyethylene). 10-15 parts, such as 10, 11, 12, 13, 15 parts; RPP (reinforced polypropylene) 5-15 parts, such as 5, 8, 10, 12, 14, 15 parts; talc 2-10 parts, such as 2, 4, 6, 8, 10 parts; lubricant 0.2-0.5 parts, such as 0.2, 0.3, 0.4, 0.5 parts; microsphere foaming agent 5-10 parts, such as 5, 6, 7, 8, 9, 10 parts; nano silica 0.5-1.5 parts, such as 0.5, 0.8, 1.0, 1.2, 1.5 parts; additives 0.5-2.5 parts, such as 0.5, 0.8, 1.0, 1.2, 1.5, 1.8, 2.0, 2.2, 2.5 parts.

[0005] This invention achieves a lighter TPO outer layer weight and a relatively softer feel compared to conventional TPO outer layers under the same process by specifically designing the TPO layer formulation. Simultaneously, by selecting specific components, costs are reduced, resulting in a superior cost-performance ratio. The weight reduction in this invention is achieved by reducing the weight of the TPO base layer. Microsphere foaming agents are added to the TPO base layer. When the microspheres are heated, the shell softens, and the alkanes vaporize, increasing internal pressure and causing rapid expansion. Upon cooling, the microspheres remain in their expanded state, thereby increasing the thickness of the adhesive layer while reducing the weight per unit area, thus achieving the weight reduction effect. Since the addition of microsphere foaming agents can affect mechanical properties, this invention uses TPO as the main resin and supplements it with RTPO, LLDPE, and RPP components as matrix resins to achieve material reinforcement. Specifically, using TPO with a specific hardness prevents the skin from cracking during high-temperature molding and stretching. The RTPO component further increases the material's hardness, which is beneficial for subsequent calendering. The addition of LLDPE improves the material's mechanical properties at room temperature, while the addition of RPP further enhances the material's high-temperature resistance and increases the hardness of the TPO skin. Furthermore, this application incorporates nano-silica to enhance the toughness of the adhesive layer, ensuring uniform and stable cell diameters during microsphere foaming, maintaining a stable cell size within 10-40 μm, and preventing cell collapse during calendering. The simultaneous addition of nano-silica and additives synergistically promotes more uniform cell size, thus ensuring consistent performance across different parts of the TPO skin.

[0006] Furthermore, the microsphere foaming agent is a closed-cell physical foaming agent with an acrylic resin shell coating alkane.

[0007] Furthermore, the particle size of the nano-silica is 20-50 nm. If the particle size is too large, the pore size will increase and the density will decrease, thereby reducing the compactness and mechanical strength of the material. At the same time, it will be difficult to disperse evenly in the system, making the material processing unstable. If the particle size is too small, the surface energy will increase significantly due to the surge in specific surface area, which will make it easy for particles to agglomerate, making it difficult to disperse evenly and leading to increased production costs.

[0008] Furthermore, the particle size of the microsphere foaming agent is 15-35 μm. If the particle size of the microsphere foaming agent is too large, it will lead to uneven cell size, which will easily cause partial collapse of the material.

[0009] Further, the TPO surface layer comprises, by weight, the following components: 50-70 parts of TPO, such as 50, 55, 60, 65, or 70 parts; 10-20 parts of RTPO, such as 10, 12, 14, 16, 18, or 20 parts; 5-10 parts of LLDPE, such as 5, 6, 7, 8, 9, or 10 parts; 10-20 parts of RPP, such as 10, 12, 14, 16, 18, or 20 parts; 2-10 parts of talc, such as 2, 4, 6, 8, or 10 parts; and 0.2-0.5 parts of lubricant, such as 0.2, 0.3, 0.4, or 0.5 parts.

[0010] Furthermore, the coating is treated with a water-based polyurethane agent.

[0011] Furthermore, the coating may, for example, employ a combination of treatment agents as follows: 1) The first version of the treatment agent used Stahl's MA-21-643 as the treatment agent to improve the adhesion between the TPO layer and the first version of the surface treatment layer; 2) The second version of the treatment agent uses Stahl's LS-96-604 as the main agent and EX-XR-96-901 as the curing agent to make the first version of the surface treatment layer adhere better to the third / fourth version of the surface treatment layer. 3) The third edition treatment agent uses Starr Company's WF-77-648 and WD-78-143 as bright paste, RU-13-085 as matte paste, XR-28-404 as curing agent, HM-13-678 as lubricant, and DF-2459 as defoamer to enhance the weather resistance and scratch resistance of TPO skin. 4) The fourth edition treatment agent uses Starr Company's WF-77-648 and WD-78-143 as bright paste, RU-13-085 as matte paste, XR-28-404 as curing agent, HM-13-678 as lubricant, and DF-2459 as defoamer to enhance the weather resistance and scratch resistance of TPO skin.

[0012] Furthermore, the additive is either POE-g-MAH or PP-g-MAH, preferably POE-g-MAH.

[0013] Furthermore, the melt index of the POE-g-MAH is 20-25 g / 10min (230℃ / 2.16 kg).

[0014] Furthermore, the TPO has a hardness of 80-85A.

[0015] Furthermore, the boiling point of the nano-silica is 195-220℃.

[0016] Furthermore, the melt index of the TPO is 13-16 g / 10min (230℃, 10kgf).

[0017] Furthermore, the RTPO has a melt flow index of 0.5-0.7 g / 10min (230℃, 2.16kgf) and a hardness of 88-92A.

[0018] Furthermore, the melt index of the LLDPE is 1.9-2.1 g / 10min (190℃, 2.16 kgf).

[0019] Furthermore, the RPP has a melt flow index of 1.35-1.62 g / 10min (190℃, 2.16kgf) and a hardness of 93-96A.

[0020] Furthermore, the nano-silica has a boiling point of 195-220℃ and a density of 0.938-0.953 g / cm³. 3 (25℃).

[0021] Furthermore, the talc powder has a whiteness of ≥90 and a particle size D50 of 5.1-5.3 μm. Adding talc powder to the system can further enhance its reinforcing effect.

[0022] Furthermore, the initiation temperature of the microsphere foaming agent is 165-175℃.

[0023] The present invention also provides a method for preparing the TPO epidermis, comprising the following steps: Weigh the TPO base layer components according to the weight and heat and mix them evenly. Then mix the TPO top layer components evenly and produce the TPO layer by calendering. The coating material is uniformly applied to the TPO layer by roller coating. Patterns are printed on the coated TPO layer by heating and extrusion, while the TPO layer and PPF layer are heat-bonded together. The finished product is inspected and packaged to obtain the TPO skin. The overall structure of the TPO skin is a coating layer, a TPO topcoat layer, a TPO basecoat layer, and a PPF layer. The present invention also provides the application of the TPO cover in automotive interiors.

[0024] In summary, compared with the prior art, the present invention achieves the following technical effects: (1) The TPO skin provided by the present invention has a significant lightweighting effect. The present invention optimizes the TPO formula, adds appropriate microsphere additives and adjusts the dosage ratio of TPO, RTPO, LLDPE and RPP, so as to achieve both lightweighting and thickening effect. (2) The TPO skin provided by the present invention has suitable softness and hardness, and has elasticity while meeting the softness requirement; (3) The TPO epidermis provided by the present invention has excellent mechanical properties. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a pore distribution diagram of the TPO epidermis in Embodiment 1 of the present invention; Figure 2 This is a pore distribution diagram of the TPO epidermis in Embodiment 2 of the present invention; Figure 3 This is a pore distribution diagram of the TPO epidermis in Comparative Example 1 of the present invention; Figure 4 This is a pore distribution diagram of the TPO epidermis in Comparative Example 2 of the present invention; Figure 5 This is a flow chart of the TPO epidermis production process in Embodiment 1 of the present invention. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] Example The present invention will be further illustrated below with reference to specific embodiments and comparative embodiments. The following specific embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments, and are not in particular limited to the types of raw materials used in the following specific embodiments.

[0029] I. The sources of raw materials for the examples and comparative examples are as follows: TPO: Grade D-85A, hardness 81A, melt flow index 15 g / 10min (230℃, 10kgf), Dawn; RTPO: Grade CA10A, hardness 90A, melt flow index 0.6 g / 10min (230℃, 2.16kgf), LyondellBasell; LLDPE: Grade 2018MA, melt index 2 g / 10min (230℃, 2.16kgf), Exxon; RPP: Hardness 95A, melt flow index 1.5 g / 10min (230℃, 2.16kgf), commercially available; Talc: Whiteness 95, particle size D50 5.2 μm, commercially available; Lubricant: Zinc stearate, commercially available; Microsphere foaming agent #1: A closed-cell physical foaming agent with an acrylic resin shell coated with alkane, with a particle size of 15-35 μm and an initiation temperature of 165-175℃, commercially available; Microsphere foaming agent #2: A closed-cell physical foaming agent with an acrylic resin shell coated with alkane, with a particle size of 35-45 μm and an initiation temperature of 145-155℃, commercially available; Nano silica: grade KH550, particle size 20 nm, boiling point 217℃, density 0.942 g / cm³ (25℃), commercially available; Additive #1: POE-g-MAH, brand name TAFMER™ MA9015, melt index is 23 g / 10min (230℃ / 2.16 kg). Additive #2: PP-g-MAH, melt index 23 g / 10min (230℃ / 2.16 kg), commercially available; Coating treatment agent: The following combination is used: 1) The first version of the treatment agent used Stahl's MA-21-643 as the treatment agent; 2) The second version of the treatment agent uses Stahl's LS-96-604 as the main agent and EX-XR-96-901 as the curing agent. 3) The third edition of the treatment agent uses Starr Company's WF-77-648 and WD-78-143 as bright paste, RU-13-085 as matte paste, XR-28-404 as curing agent, HM-13-678 as lubricant, and DF-2459 as defoamer. 4) The fourth edition of the treatment agent uses Starr Company's WF-77-648 and WD-78-143 as bright paste, RU-13-085 as matte paste, XR-28-404 as curing agent, HM-13-678 as lubricant, and DF-2459 as defoamer. The TPO topcoat formulation, by weight, includes the following components: 65 parts TPO, 20 parts RTPO, 10 parts LLDPE, 12 parts RPP, 8 parts talc, and 0.2 parts lubricant. The preparation method of TPO epidermis in the embodiments and comparative examples of the present invention includes the following steps: Weigh the TPO base layer components according to the weight and heat and mix them evenly. Then mix the TPO top layer components evenly and produce the TPO layer by calendering. The coating material is uniformly applied to the TPO layer by roller coating. Patterns are printed on the coated TPO layer by heating and extrusion, while the TPO layer and PPF layer are heat-bonded together. The finished product is inspected and packaged to obtain the TPO skin. The overall structure of the TPO skin is a coating layer, a TPO topcoat layer, a TPO basecoat layer, and a PPF layer.

[0030] II. Performance Testing Methods (1) TPO skin thickness test: The thickness test was conducted using a thickness gauge in accordance with the standard QB / T 2709.

[0031] (2) TPO skin weight test: The test was conducted using an analytical balance with an accuracy of 0.1 mg. Three 100 mm × 100 mm samples were placed on the analytical balance and weighed to an accuracy of 1 mg. The measurement results were converted to g / m². The test results were expressed as the arithmetic mean of the three samples and were rounded to the nearest integer.

[0032] (3) TPO surface hardness test: Performed in accordance with GB / T 531.1 standard, using a hardness tester to test Shore A hardness.

[0033] (4) TPO skin tensile strength and elongation test: According to GB / T 13022-1991, type 1 specimens, at least 3 specimens in each direction, at a speed of (200±10) mm / min. Take the arithmetic mean of the data in each direction, retain the tensile strength to the first decimal place, and retain the nominal strain at tensile break to the integer place.

[0034] (5) TPO epidermal tear strength test: According to the standard of QB / T 1130, at least 3 in each direction, at a speed of (200±10) mm / min, take the arithmetic mean of the data in each direction and keep it to the integer part.

[0035] Table 1. Technical solutions and effects of the embodiments (unit: parts by weight)

[0036] The TPO skins prepared in Examples 1-5 employ the specific TPO adhesive formulation of this invention, and simultaneously incorporate TPO, RTPO, LLDPE, PP, microsphere foaming agent, talc, lubricant, nano-silica, and specific additives. Through the combination of microsphere foaming agent and various resin materials, not only is the TPO skin lightweight, but its mechanical properties are also guaranteed. At the same time, the material has moderate softness and hardness, which can meet the market demand when used as a vacuum-sealed skin for interiors of new energy vehicles.

[0037] Comparative Examples 1 and 3-5 were compared with Example 1, and Comparative Example 2 was compared with Example 2. No microsphere foaming agent, nano silica, or additives were added in Comparative Example 1. In Comparative Example 2, the amount of microsphere foaming agent added was too large, resulting in larger cells, an excessively high foaming ratio, and a significant decrease in mechanical properties. No microsphere foaming agent was added in Comparative Example 3, no nano silica was added in Comparative Example 4, and no additives were added in Comparative Example 5. In Comparative Examples 4 and 5, the addition of either nano silica or one of the additives alone would reduce the uniformity of the cells, leading to localized performance instability in the product. That is, areas with smaller cells exhibited good mechanical properties, while areas with larger cells showed decreased performance, making it difficult to accurately reflect the product's performance.

[0038] None of the above comparisons can simultaneously guarantee a balance between lightweight materials and mechanical properties.

[0039] Based on the test data of TPO skin hardness, weight and mechanical properties in Table 1, the TPO skin prepared by Examples 1-5 has significant advantages over the comparative examples and can effectively meet the high standards of customers and the market.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A TPO epidermis, characterized in that, It comprises a three-layer structure consisting of a coating layer, a TPO layer, and a PPF layer. The TPO layer includes a TPO topcoat layer and a TPO basecoat layer. The TPO basecoat layer, by weight, comprises the following components: TPO 50-70 servings RTPO 10-15 portions LLDPE 10-15 parts RPP 5-15 servings 2-10 parts talcum powder Lubricant 0.2-0.5 parts 5-10 parts of microsphere foaming agent 0.5-1.5 parts of nano-silica Additives: 0.5-2.5 parts.

2. The TPO epidermis according to claim 1, characterized in that, The microsphere foaming agent is a closed-cell physical foaming agent with an acrylic resin shell coating alkane.

3. The TPO epidermis according to claim 1, characterized in that, The microsphere foaming agent has a particle size of 15-35 μm.

4. The TPO epidermis according to claim 1, characterized in that, The TPO surface adhesive layer comprises the following components by weight: TPO 50-70 servings RTPO 10-20 portions LLDPE 5-10 parts 10-20 RPP 2-10 parts talcum powder 0.2-0.5 parts of lubricant.

5. The TPO epidermis according to claim 1, characterized in that, The coating is applied using a water-based polyurethane treatment agent.

6. The TPO epidermis according to claim 1, characterized in that, The auxiliary agent is either POE-g-MAH or PP-g-MAH.

7. The TPO epidermis according to claim 1, characterized in that, The hardness of the TPO is 80-85A.

8. The TPO epidermis according to claim 1, characterized in that, The boiling point of the nano-silica is 195-220℃.

9. The method for preparing TPO epidermis according to any one of claims 1-8, characterized in that, Includes the following steps: Weigh the TPO base layer components according to the weight and heat and mix them evenly. Then mix the TPO top layer components evenly and produce the TPO layer by calendering. The coating material is uniformly applied to the TPO layer by roller coating. Patterns are printed on the coated TPO layer by heating and extrusion, while the TPO layer and PPF layer are heat-bonded together. The finished product is inspected and packaged to obtain the TPO skin. The overall structure of the TPO skin is a coating layer, a TPO topcoat layer, a TPO basecoat layer, and a PPF layer.

10. The application of the TPO leather according to any one of claims 1-8 in automotive interiors.

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