Preparation method of synthetic leather and electronic equipment shell

Abstract

The invention relates to the technical field of synthetic leather, in particular to a preparation method of synthetic leather and an electronic equipment shell. The preparation method of the synthetic leather comprises the following steps: preparing a TPU master batch, and treating the TPU master batch to prepare a TPU substrate layer; a PU layer is arranged on the surface of one side of the TPU substrate layer, and a synthetic leather substrate is prepared; the surface of the side, away from the TPU substrate layer, of the PU layer serves as a laser etching face, the preset laser etching pattern area of the synthetic leather substrate is subjected to laser etching treatment, the laser etching depth of the laser etching treatment reaches the TPU substrate layer, and the synthetic leather is prepared. The synthetic leather prepared by the invention has the advantages of smooth laser pattern, rich layers and good visual effect.

Description

Technical Field

[0001] This application relates to the technical field of synthetic leather, specifically to a preparation method of synthetic leather and the outer shell of electronic devices. Background Art

[0002] In the rapid development of the electronics industry, the appearance design of the back covers or protective covers of electronic products such as mobile phones and laptops has become particularly important. After going through the transformation of shell materials such as plastic, metal, and glass, new materials such as synthetic leather and suede have been incorporated into existing electronic products. Different from the cold and hard shell materials of traditional electronic products, these materials can soften the touch and enrich the design elements.

[0003] Currently, the synthetic leather used in electronic products is mainly PU synthetic leather and silicone synthetic leather. Generally, the base of PU synthetic leather materials is materials such as nylon fabric base, Oxford fabric base, fiberglass fabric base, cotton fabric base, Jiaji fabric base, and ultra-fine fiber fabric base. The above bases have no ductility, and when compounded with shell materials such as plastic, fiber-reinforced composite materials, metal, and glass, poor adhesion is likely to occur, resulting in problems such as corner wrinkles and easy delamination. And the current synthetic leather materials only rely on the outermost layer as the appearance layer, with a single visual effect and lack of layering. Summary of the Invention

[0004] Based on this, in view of the problems of weak adhesion and single visual effect of synthetic leather, it is necessary to provide a preparation method of synthetic leather.

[0005] In the first aspect of this application, a preparation method of synthetic leather is provided, including the following steps:

[0006] Prepare a TPU masterbatch, process the TPU masterbatch to prepare a TPU-based bottom layer;

[0007] Set a PU layer on one side surface of the TPU-based bottom layer to prepare a synthetic leather substrate;

[0008] Taking the side surface of the PU layer away from the TPU-based bottom layer as the laser engraving surface, perform laser engraving treatment on the preset laser engraving pattern area of the synthetic leather substrate, and the laser engraving depth of the laser engraving treatment reaches the TPU-based bottom layer to prepare the synthetic leather.

[0009] In one embodiment, the number of layers of the TPU-based bottom layer is one layer or multiple layers.

[0010] Among them, when the number of layers of the TPU-based bottom layer is one layer, the steps of laser engraving treatment include: taking the side surface of the PU layer away from the TPU-based bottom layer as the laser engraving surface, performing laser engraving treatment on the preset laser engraving pattern area of the PU layer and the TPU-based bottom layer, and the laser engraving depth of the laser engraving treatment reaches the TPU-based bottom layer, and the laser engraving depth is less than the sum of the thicknesses of the PU layer and the TPU-based bottom layer and greater than the thickness of the PU layer.

[0011] Alternatively, when the number of layers of the TPU base layer is multiple, the TPU base layer includes a first sub-layer, ……, and an Nth sub-layer that are stacked in a direction away from the PU layer; N is a positive integer ≥ 2; the steps of laser engraving treatment include: taking the surface of the PU layer away from the TPU base layer as the laser engraving surface, and performing laser engraving treatment on the preset laser engraving pattern area of the PU layer and the TPU base layer, wherein at least the first sub-layer is included in the TPU base layer for laser engraving treatment, and the total depth of the laser engraving treatment is less than the thickness of the synthetic leather substrate and greater than the thickness of the PU layer.

[0012] In one embodiment, the steps of treating the TPU masterbatch include stirring treatment, melting and forming treatment performed in sequence; the steps of treating the TPU masterbatch have one or more of the following characteristics:

[0013] (1) The process parameters of the stirring treatment include: the rotation speed is 600 rpm to 1000 rpm;

[0014] (2) The process parameters of the melting include: the melting temperature is 180 °C to 220 °C;

[0015] (3) Before the step of stirring the TPU masterbatch, there is also a step of performing dry pretreatment on the TPU masterbatch;

[0016] (4) The thickness of the TPU base layer is 0.1 mm to 0.4 mm;

[0017] (5) The Shore hardness of the TPU base layer is 60A to 90A;

[0018] (6) The thickness of the synthetic leather substrate is 0.2 mm to 0.6 mm;

[0019] (7) When the number of layers of the TPU base layer is one, the forming treatment method is calendering or extrusion;

[0020] (8) When the number of layers of the TPU base layer is multiple, the forming treatment methods include one or more of calendering, gluing, laminating, hot pressing and co-extrusion;

[0021] (9) The methods of setting the PU layer on one side surface of the TPU base layer include one or more of gluing, laminating, hot pressing and co-extrusion.

[0022] In one embodiment, when the number of layers of the TPU base layer is one or multiple, the TPU masterbatches each independently include the following components in parts by weight: 60 parts to 100 parts of TPU particles, 1 part to 3 parts of lubricant, and 1 part to 3 parts of compatibilizer;

[0023] Among them, the TPU particles include one or more of polyester-based polyurethane particles, polyether-based polyurethane particles, and aliphatic polyurethane particles.

[0024] In one embodiment, the TPU masterbatch further includes: a functional component; the functional component includes one or more of a color masterbatch, pearlescent powder, thermochromic pigment, and rare earth fluorescent powder;

[0025] Among them, based on parts by weight, the TPU masterbatch includes 0.01 part to 15 parts of the color masterbatch;

[0026] Based on parts by weight, the TPU masterbatch includes 0.01 part to 15 parts of the pearlescent powder;

[0027] Based on parts by weight, the TPU masterbatch includes 0.01 part to 15 parts of the thermochromic pigment;

[0028] Based on parts by weight, the TPU masterbatch includes 0.01 part to 15 parts of the rare earth fluorescent powder.

[0029] In one embodiment, when the number of layers of the TPU base layer is multiple, in the TPU masterbatch for preparing each sub-layer of the TPU base layer, the parts by weight of the color masterbatch and / or the pearlescent powder and / or the thermochromic pigment and / or the rare earth fluorescent powder are different.

[0030] In another embodiment, when the number of layers of the TPU base layer is multiple, in the TPU masterbatch for preparing each sub-layer of the TPU base layer, the types of the color masterbatch and / or the pearlescent powder and / or the thermochromic pigment and / or the rare earth fluorescent powder are different.

[0031] In one embodiment, the TPU masterbatch independently further includes: a flame retardant;

[0032] Among them, based on parts by weight, the TPU masterbatch includes 0.2 part to 15 parts of the flame retardant.

[0033] In one embodiment, the TPU masterbatch independently further includes: an antibacterial agent;

[0034] Among them, based on parts by weight, the TPU masterbatch includes 0.3 part to 10 parts of the antibacterial agent.

[0035] In the second aspect of the present application, there is provided an electronic device housing, including a synthetic leather and a base material layer, and the synthetic leather is the synthetic leather prepared by the preparation method according to any one of the first aspects of the present application;

[0036] Among them, the TPU base layer is disposed close to the base material layer.

[0037] In one embodiment, the substrate layer is any one of a plastic layer, a fiber-reinforced composite layer, a glass layer, or a metal layer.

[0038] The preparation method of the synthetic leather of the present application has at least the following advantages:

[0039] In the present application, the thermoplastic polyurethane elastomer (TPU) masterbatch is successively stirred, melted, and formed. This process helps to evenly mix the TPU masterbatch, ensure the consistency and stability of the performance of the TPU base layer, and avoid performance differences caused by uneven composition distribution. Further, a PU layer is provided on the TPU base layer. At this time, the synthetic leather substrate has high strength, high elasticity, a soft touch, and good weather resistance, thereby improving the practical performance and application range of the synthetic leather.

[0040] Taking the surface of the PU layer away from the TPU base layer as the laser engraving surface, the laser engraving depth of the laser engraving treatment reaches the TPU base layer. At this time, the TPU material of the base layer is locally melted during the laser engraving process and re-solidifies after melting. Therefore, a laser engraving pattern with a smooth surface can be formed in the preset laser engraving pattern area of the TPU base layer, thereby giving the synthetic leather rich layers and good visual effects.

[0041] In addition, the flexibility and elasticity of the TPU base layer enable it to closely fit various shell materials such as plastic, metal, and glass when used for preparing the composite shell of an electronic device, thereby effectively overcoming the problems of corner wrinkles and easy delamination caused by poor fitting of traditional base fabrics such as polyester cloth and fiberglass cloth, and greatly improving the structural stability of the composite shell.

[0042] Furthermore, the synthetic leather obtained by the preparation method provided in the present application has stable quality and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic cross-sectional structure diagram of the synthetic leather provided by an example of the present application;

[0044] Figure 2 It is a top view structure diagram of the synthetic leather provided by an example of the present application;

[0045] Figure 3 It is a schematic cross-sectional structure diagram of the synthetic leather provided by another example of the present application;

[0046] Figure 4 It is a schematic cross-sectional structure diagram of the synthetic leather provided by still another example of the present application;

[0047] Figure 5 It is a schematic cross-sectional structure diagram of the synthetic leather provided by yet another example of the present application;

[0048] Figure 6Schematic cross-sectional structure diagram of the synthetic leather provided for another example of the present application;

[0049] Figure 7 Schematic cross-sectional structure diagram of the synthetic leather provided for another example of the present application;

[0050] Figure 8 Schematic cross-sectional structure diagram of the synthetic leather provided for another example of the present application;

[0051] Figure 9 Schematic cross-sectional structure diagram of the synthetic leather provided for another example of the present application;

[0052] Figure 10 Schematic cross-sectional structure diagram of the synthetic leather provided for another example of the present application;

[0053] Figure 11 Schematic structure diagram of the housing of an electronic device provided for an example of the present application.

[0054] In the figure, 10 is the synthetic leather; 100 is the TPU base layer; 200 is the PU layer; 110 is the laser pattern; 210 is the laser scratch; 300 is the foaming layer; 400 is the barrier layer; 500 is the surface layer; 600 is the surface treatment layer; 700 is the touch layer. Detailed implementation manners

[0055] The following further describes the preparation method of the synthetic leather, the housing of the electronic device and its preparation method of the present application in a more complete and clear manner in combination with specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosed content of the present application more thorough and comprehensive.

[0056] In the present application, "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0057] When a numerical range is disclosed herein, the above range is considered continuous and includes the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when the range refers to integers, it includes each integer between the minimum and maximum values of the range. In addition, when providing multiple ranges to describe features or characteristics, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0058] In the first aspect of the present application, a method for preparing synthetic leather is provided, including the following steps:

[0059] S10: Prepare a TPU masterbatch, process the TPU masterbatch to prepare a TPU base layer.

[0060] S20: Set a PU layer on one side surface of the TPU base layer to prepare a synthetic leather substrate.

[0061] S30: Using the side surface of the PU layer away from the TPU base layer as the laser engraving surface, perform laser engraving on the preset laser engraving pattern area of the synthetic leather substrate. The laser engraving depth of the laser engraving process reaches the TPU base layer to prepare synthetic leather.

[0062] In step S10 of the present application, the thermoplastic polyurethane elastomer (TPU) masterbatch is successively stirred, melted, and formed. This process helps the TPU masterbatch to be evenly mixed. At the same time, the molecular chain segments of TPU stretch and intertwine with each other, further enhancing the consistency and stability of the performance of the TPU base layer.

[0063] In step S20, a PU layer is further set on the TPU base layer. At this time, the synthetic leather substrate has both high strength, high elasticity, a soft touch, and good weather resistance, thereby improving the practical performance and application range of the synthetic leather.

[0064] In step S30, using the side surface of the PU layer away from the TPU base layer as the laser engraving surface, the laser engraving depth of the laser engraving process reaches the TPU base layer. At this time, the TPU material of the base layer is locally melted during the laser engraving process and re-solidifies after melting. Therefore, a laser engraving pattern with a smooth surface can be formed in the preset laser engraving pattern area. When the PU layer is used as the apparent surface, the synthetic leather can have rich layers and good visual effects.

[0065] In addition, the flexibility and elasticity of the TPU base layer enable it to closely fit various shell materials such as plastic, metal, and glass when used to prepare a composite shell for an electronic device. Thereby, it effectively overcomes the problems of corner wrinkles and easy delamination caused by poor fitting of traditional base fabrics such as polyester cloth and fiberglass cloth, and greatly improves the structural stability of the composite shell.

[0066] Furthermore, the synthetic leather obtained by the preparation method provided in the present application has stable quality and is suitable for large-scale industrial production.

[0067] In one example, in step S10, the steps of processing the TPU masterbatch include successively performing a stirring process, a melting process, and a forming process.

[0068] Exemplarily, the process parameters of the stirring treatment include: the rotation speed is 600 rpm to 1000 rpm. It can be understood that the rotation speed of the stirring treatment can be selected from any value between 600 rpm and 1000 rpm. The rotation speed of the stirring treatment includes but is not limited to 600 rpm, 700 rpm, 800 rpm, 900 rpm or 1000 rpm, or within the range formed by any two of the above point values as the end point values. When the rotation speed is limited to 600 rpm to 1000 rpm during the stirring treatment, it can promote the efficient dispersion of each component of the TPU masterbatch at the microscopic state, making the composition of the TPU material uniform. After subsequent melting and extrusion, a TPU base layer with stable and consistent performance can be prepared.

[0069] The stirring time of the stirring treatment plays an important role in ensuring the full blending of each component in the TPU masterbatch. Further, the process parameters of the stirring treatment also include: the stirring time is 5 min to 15 min. Exemplarily, the stirring time includes but is not limited to 5 min, 10 min or 15 min.

[0070] Exemplarily, the process parameters of the melting include: the melting temperature is 180 °C to 220 °C. The melting temperature of 180 °C to 220 °C can not only melt the TPU masterbatch evenly and thoroughly, ensuring that the molecular chains are fully stretched and intertwined, but also reduce the risk of material decomposition of the TPU masterbatch due to too high temperature. Exemplarily, the melting temperature includes but is not limited to 180 °C, 190 °C, 200 °C, 210 °C or 220 °C.

[0071] In one example, the equipment for the stirring treatment and the melting treatment is a twin-screw extruder.

[0072] In one example, before the step of performing the stirring treatment on the TPU masterbatch, there is also a step of performing a drying pretreatment on the TPU masterbatch.

[0073] Further, the process parameters of the drying pretreatment include: the drying temperature is 60 °C to 80 °C, and the drying time is 4 h to 6 h. By performing a drying pretreatment on the TPU masterbatch, the moisture and other volatile impurities in the TPU masterbatch can be removed, avoiding problems such as bubble generation and hydrolysis during the melting process, thereby improving the quality and performance stability of the TPU base layer.

[0074] Further exemplarily, step S10 includes: preparing a TPU masterbatch, performing a drying pretreatment, a stirring treatment, melting, and a forming treatment on the TPU masterbatch to prepare a TPU base layer.

[0075] In one example, the thickness of the TPU base layer is 0.1 mm to 0.4 mm. In this application, since the laser engraving depth of the laser engraving process reaches the TPU base layer, the thickness of the TPU base layer plays an important role in preventing abnormal energy penetration, excessive material ablation during the laser engraving process, and ensuring the integrity of the laser engraved pattern. Exemplarily, the thickness of the TPU base layer includes, but is not limited to, 0.1 mm, 0.2 mm, 0.3 mm, or 0.4 mm.

[0076] In one example, the Shore hardness of the TPU base layer is 60A to 90A. Exemplarily, the Shore hardness of the TPU base layer includes, but is not limited to, 60A, 65A, 70A, 75A, 80A, 85A, or 90A, or within the range formed by any two of the above point values as the end point values.

[0077] The material with the above Shore hardness can better maintain its own structure during the laser engraving process, effectively avoiding the phenomenon of incomplete patterns caused by being too hard to engrave or the edges of the patterns melting and deforming due to being too soft, and reducing defects such as burrs and serrations, ensuring the complete and accurate presentation of the patterns. At the same time, the TPU base layer with the above Shore hardness can also adjust the pressing touch of the entire synthetic leather and enhance the user's use experience.

[0078] In one example, the number of layers of the TPU base layer is one layer or multiple layers. It can be understood that in this application, the number of layers of the TPU base layer is not limited. When the TPU base layer is multiple layers, the components of the TPU masterbatch for preparing each sub-layer of the TPU base layer are also independent of each other.

[0079] In one example, when the number of layers of the TPU base layer is one layer, the forming process is calendering or extrusion.

[0080] In one example, when the number of layers of the TPU base layer is multiple layers, the forming process methods include one or more of calendering, gluing, laminating, hot pressing, and co-extrusion.

[0081] Exemplarily, when the number of layers is multiple layers, the steps of preparing the TPU base layer by co-extrusion include: formulating the TPU masterbatch for each sub-layer in the TPU base layer, respectively performing drying pretreatment, stirring treatment, and melting treatment on the TPU masterbatch for preparing each sub-layer, and then converging the TPU masterbatch for each sub-layer into a co-extrusion die, so that the TPU masterbatch for each sub-layer is compounded in a predetermined manner to prepare a TPU base layer with multiple layers.

[0082] In this application, when the number of layers of the TPU base layer is multiple layers, the TPU base layer includes a first sub-layer, ……, and an Nth sub-layer stacked in a direction away from the PU layer; N is a positive integer ≥ 2. Exemplarily, the value of N includes, but is not limited to, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0083] Further, the number of layers of the TPU base layer is 1 to 3. Further exemplarily, the number of layers of the TPU base layer includes but is not limited to 1, 2 or 3 layers.

[0084] In one example, when the number of the TPU base layer is one or more layers, the TPU masterbatch independently includes the following components in parts by weight: 60 to 150 parts of TPU particles, 1 to 3 parts of lubricant, and 1 to 3 parts of compatibilizer.

[0085] Further, in the TPU masterbatch, the weight proportions of TPU particles include but are not limited to 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts or 100 parts. The weight proportions of lubricants include but are not limited to 1 part, 1.5 parts, 2 parts, 2.5 parts or 3 parts. The weight proportions of compatibilizers include but are not limited to 1 part, 1.5 parts, 2 parts, 2.5 parts or 3 parts. The TPU masterbatch provided in the present application can not only ensure the basic properties of TPU particles such as high elasticity, but also improve its processing performance during stirring, melting, molding and the like, and improve the compatibility of each component under the condition of reasonable matching of TPU particles, lubricants and compatibilizers and their weight proportions.

[0086] It can be understood that when the number of layers of the TPU base layer is multiple, the weight fractions of TPU particles, lubricant and compatibilizer in the TPU masterbatch used to prepare each sub-layer of the TPU base layer are independent of each other. That is, in the TPU masterbatch used as the raw material for preparing each sub-layer, the type, weight fraction, etc. of each component are independently the same or different.

[0087] In one example, the TPU particles include one or more of polyester polyurethane particles, polyether polyurethane particles, and aliphatic polyurethane particles. For example, the model of the polyester polyurethane particles includes, but is not limited to, GP85, GP95AB, or H2342. The model of the polyether polyurethane particles includes, but is not limited to, BASF 1185A. The model of the aliphatic polyurethane particles includes, but is not limited to, PU-836.

[0088] In one example, the type of lubricant includes, but is not limited to, Clariant E wax, montan wax, butyl stearate, stearyl stearate, oleamide, erucamide, or ethylene bis stearamide.

[0089] In one example, the type of compatibilizer includes but is not limited to maleic anhydride grafted polyolefin, styrene-maleic anhydride copolymer or silane coupling agent.

[0090] In one example, each TPU masterbatch independently further includes: a functional component, wherein the functional component includes one or more of a color masterbatch, pearlescent powder, a thermochromic pigment, and a rare earth fluorescent powder.

[0091] After adding functional components such as color masterbatch, pearlescent powder, thermochromic pigment, and rare earth fluorescent powder to the TPU masterbatch, there will be an obvious color difference between the TPU base layer and the PU layer prepared therefrom. At this time, laser engraving treatment is performed until the TPU base layer, so the laser engraving pattern formed on the TPU base layer will be different from the surrounding colors, and thus the laser engraving pattern can have high recognition.

[0092] Understandably, when the number of layers of the TPU base layer is multiple, functional components can be independently added to the TPU masterbatch of each sub-layer of the TPU base layer.

[0093] Exemplarily, when the TPU base layer is 2 layers, the TPU base layer includes a first sub-layer and a second sub-layer stacked in a direction away from the PU layer. Among them, functional components are independently added to the first sub-layer and the second sub-layer.

[0094] Another exemplarily, when the TPU base layer is 3 layers, the TPU base layer is sequentially provided with a first sub-layer, a second sub-layer, and a third sub-layer on a surface on the side facing away from the PU layer. Among them, functional components are independently added to the first sub-layer, the second sub-layer, and the third sub-layer.

[0095] In one example, by weight, the TPU masterbatch includes 0.01 parts to 15 parts of color masterbatch. Exemplarily, the weight parts of the color masterbatch include but are not limited to 0.01 part, 0.5 part, 1 part, 5 parts, 10 parts, or 15 parts.

[0096] In one example, by weight, the TPU masterbatch includes 0.01 parts to 15 parts of pearlescent powder. Exemplarily, the weight parts of the pearlescent powder include but are not limited to 0.01 part, 0.5 part, 1 part, 5 parts, 10 parts, or 15 parts. After adding pearlescent powder to the TPU masterbatch, a TPU base layer with a pearlescent effect can be revealed after laser engraving treatment, which can enhance the texture of the synthetic leather, increase the color layering and three-dimensional sense. Further, the types of pearlescent powder include but are not limited to mica pearlescent powder. Further exemplarily, the D50 particle size of the mica pearlescent powder is 4μm to 25μm.

[0097] In one example, by weight, the TPU masterbatch includes 0.01 parts to 15 parts of thermochromic pigment. Exemplarily, the weight parts of the thermochromic pigment include but are not limited to 0.01 part, 0.5 part, 1 part, 5 parts, 10 parts, or 15 parts. After the laser engraving treatment reveals the TPU base layer containing the thermochromic pigment, it can display laser patterns of different colors at different temperatures, thereby enriching the display effects at different temperatures.

[0098] In one example, based on parts by weight, the TPU masterbatch includes 0.01 part to 15 parts of rare earth fluorescent powder. Exemplarily, the parts by weight of the rare earth fluorescent powder include, but are not limited to, 0.01 part, 0.5 part, 1 part, 5 parts, 10 parts or 15 parts. After the laser engraving treatment reveals the TPU base layer containing the rare earth fluorescent powder, the TPU base layer can absorb sunlight and ultraviolet light during the day and achieve a special effect of emitting light under night or dark conditions, thus enriching the visual display effect at night. The types of rare earth fluorescent powder include, but are not limited to, rare earth aluminates and rare earth silicates. Further exemplarily, the D50 particle size of the rare earth fluorescent powder is 2 μm to 8 μm.

[0099] The above-mentioned color developer in parts by weight has good compatibility with other components in the TPU masterbatch and is suitable for the processing and preparation processes of stirring, melting and molding. At the same time, the dosage of the color developer within the above range can flexibly blend a variety of colors to meet the personalized color requirements of different synthetic leather products.

[0100] In one example, when the number of layers of the TPU base layer is multiple, in the TPU masterbatch for preparing each sub-layer in the TPU base layer, the mass fractions of the color masterbatch and / or pearlescent powder and / or thermochromic pigment and / or the rare earth fluorescent powder are different.

[0101] In another example, when the number of layers of the TPU base layer is multiple, in the TPU masterbatch for preparing each sub-layer in the TPU base layer, the types of the color masterbatch and / or pearlescent powder and / or thermochromic pigment and / or the rare earth fluorescent powder are different.

[0102] By differentially adding functional components to the multi-layer structure of the TPU base layer, there are obvious appearance differences on different levels of the TPU base layer. After the laser engraving treatment, the laser engraving pattern formed in the preset laser engraving pattern area has high recognition, and the TPU base layer can achieve the effect of multi-color gradient or multi-layer color display, thereby ensuring the visual effect and improving the layering.

[0103] In one example, the TPU masterbatch independently further includes: a flame retardant.

[0104] In one example, based on parts by weight, the TPU masterbatch includes 1 part to 15 parts of a flame retardant. Exemplarily, the parts by weight of the flame retardant include, but are not limited to, 1 part, 5 parts, 10 parts or 15 parts.

[0105] Exemplarily, the types of the flame retardant include, but are not limited to, zirconium phosphate compounded with aluminum diethyl phosphinate (ADP), aluminum hypophosphite (AHP), melamine cyanurate (MCA), ammonium sulfamate (AS), ammonium polyphosphate or polyphosphazene.

[0106] A flame retardant is added to the TPU masterbatch, i.e., the TPU base layer. At this time, it can not only ensure the flame retardancy of the overall synthetic leather, but also avoid the performance deterioration such as the reduction of the flexibility of the surface functional layer and the decrease of the scratch resistance in other surface functional layers such as the PU layer.

[0107] In one example, the TPU masterbatch independently further includes: an antibacterial agent.

[0108] In one example, by weight, the TPU masterbatch includes 1 part to 10 parts of the antibacterial agent.

[0109] Exemplarily, the types of the antibacterial agent include but are not limited to silver ion antibacterial agents, polymeric quaternary ammonium salts or chitosan.

[0110] An antibacterial agent is added to the TPU masterbatch, i.e., the TPU base layer. On the one hand, the TPU base layer is located inside the synthetic leather. At this time, the antibacterial agent can be slowly released, thereby forming a continuous antibacterial environment, which is beneficial to inhibiting the growth and reproduction of bacteria on the entire synthetic leather. On the other hand, when the TPU base layer can effectively ensure that the synthetic leather has antibacterial properties, it can avoid adding antibacterial agents to other surface functional layers such as the PU layer, thereby avoiding performance deterioration problems such as reduced gloss and damaged waterproof structure caused by adding antibacterial agents to the surface functional layer.

[0111] In one example, in step S20, the method of setting the PU layer on one side surface of the TPU base layer includes one or more of gluing, laminating, hot pressing and coextrusion.

[0112] The good flexibility and elasticity of the TPU base layer enable it to better adapt to the shape and deformation of the PU layer during the bonding processes such as gluing, laminating, hot pressing and coextrusion, reducing problems such as poor bonding or cracks caused by stress concentration.

[0113] In one example, when the number of layers of the TPU base layer is one layer, step S30: the steps of laser engraving treatment include:

[0114] Taking the side surface of the PU layer away from the TPU base layer as the laser engraving surface, performing laser engraving treatment on the preset laser engraving pattern areas of the PU layer and the TPU base layer, and the laser engraving depth of the laser engraving treatment reaches the single-layer TPU base layer, and the laser engraving depth is less than the sum of the thicknesses of the PU layer and the TPU base layer and greater than the thickness of the PU layer.

[0115] In another example, when the number of layers of the TPU base layer is multiple, the TPU base layer includes a first sub-layer, ……, and an Nth sub-layer that are stacked in a direction away from the PU layer; N is a positive integer greater than or equal to 2. The steps of the laser engraving process include: using the surface of the PU layer away from the TPU base layer as the laser engraving surface, and performing laser engraving on the preset laser engraving pattern area of the PU layer and the TPU base layer. Among them, the TPU base layer for which the laser engraving process is performed includes at least the first sub-layer, and the laser engraving depth is less than the thickness of the synthetic leather substrate and greater than the thickness of the PU layer.

[0116] It can be understood that when the TPU base layer is multiple layers, at least the first sub-layer is laser engraved, and the remaining sub-layers can be laser engraved or not.

[0117] In one example, when the TPU base layer is multiple layers, the laser engraving depth is independently set for each sub-layer of the TPU base layer. It can be understood that the laser engraving depths are independently the same or different. The laser engraving process can reach different depths in different sub-layers at different positions, as long as the laser engraving depth is less than the thickness of the synthetic leather substrate and greater than the thickness of the PU layer. At this time, when the TPU base layer is multiple layers, multiple laser engraving patterns are independently formed in each sub-layer of the TPU base layer.

[0118] In one example, when the TPU base layer is multiple layers, among two adjacent sub-layers, the size of the preset laser engraving pattern area of the sub-layer closer to the PU layer is not less than the size of the preset laser engraving pattern area of the sub-layer farther from the PU layer. At this time, the preset laser engraving area of the sub-layer closer to the PU layer is larger, which is more conducive to the laser engraving process of the lower TPU base layer sub-layer and can make the laser engraving pattern present a three-dimensional visual effect.

[0119] Traditional methods generally form laser engraving patterns on surface functional layers such as the PU layer. However, the PU layer is a thermosetting polymer layer with a cross-linked structure inside. During the laser engraving process, the surface of the thermosetting polymer layer will undergo carbonization decomposition under high temperature, rather than presenting a melting state, which causes the laser engraving patterns formed on the surface of thermosetting polymer layers such as PU to have rough surfaces and accompanied by charred marks.

[0120] In this application, the laser engraving process reaches the TPU base layer, and at this time, the laser engraving pattern is formed on the surface of the TPU base layer. During the laser engraving process, the thermoplasticity of TPU causes the surface of the TPU base layer to locally melt, and the melted substances on its surface re-solidify after cooling, thus forming a laser engraving pattern with a smooth surface.

[0121] In one of the examples, the process parameters of laser engraving include: the laser wave type is ultraviolet light, the laser engraving speed is 120mm / s~180mm / s, the laser engraving frequency is 20KHz~30KHz, and the laser engraving current is 1.5A~3A.

[0122] In one example, the thickness of the synthetic leather substrate is 0.2mm~0.6mm. The thickness of the synthetic leather substrate is between 0.2mm~0.6mm, which can ensure that the synthetic leather has good flexibility and fit, and can control costs and reduce the overall weight of the product while ensuring strength and durability.

[0123] In one example, the synthetic leather further comprises a functional layer, wherein the functional layer comprises at least one of a foaming layer, a barrier layer, a surface layer, a surface treatment layer and a touch layer.

[0124] It can be understood that the above functional layers are independently arranged on the surface of the PU layer on the side away from the TPU base layer, or between the PU layer and the TPU base layer. In the present application, the materials of the foaming layer, barrier layer, surface layer, surface treatment layer and touch layer are not limited, as long as the corresponding buffering, barrier, decoration, touch optimization or surface protection functions can be achieved.

[0125] For example, the material of the foaming layer includes but is not limited to foamed polyurethane resin. For further example, the foamed polyurethane resin includes but is not limited to polyester polyurethane, polyether polyurethane or polycarbonate polyurethane.

[0126] For example, the material of the barrier layer includes but is not limited to barrier polyurethane resin. For further example, the barrier polyurethane resin includes but is not limited to acrylate modified polyurethane barrier resin or polycarbonate barrier polyurethane resin.

[0127] For example, the material of the surface layer includes but is not limited to the surface layer polyurethane resin. For further example, the raw materials for preparing the surface layer include polyurethane prepolymer, vinyl-terminated polysiloxane, hydrogen-containing polysiloxane, reaction inhibitor, catalyst, silica, cyclic siloxane, polyisocyanate curing agent and compatibilizer. Among them, the polyurethane prepolymer is obtained by reacting polyol, terminal hydroxyl polysiloxane and polyisocyanate. The suitable hardness, softness and touch of the surface layer can simulate the texture of natural leather and improve the quality of synthetic leather. It is understandable that the present application does not limit the color of the surface layer, and the surface layer can present any color according to demand.

[0128] For example, the material of the surface treatment layer includes but is not limited to water-based aromatic polyurethane resin. For further example, the model of the water-based aromatic polyurethane resin includes but is not limited to KTT728-7A.

[0129] For example, the material of the touch layer includes, but is not limited to, polyurethane, silicone and polyolefin.

[0130] In one example, the functional layer includes a foaming layer and a barrier layer. The foaming layer and the barrier layer are disposed between the TPU base layer and the PU layer, and the foaming layer is disposed closer to the TPU base layer.

[0131] In one example, the functional layer includes a surface treatment layer. The surface treatment layer is disposed on the surface of the PU layer facing away from the TPU base layer.

[0132] In one example, the functional layer includes a foaming layer, a barrier layer, and a surface treatment layer. The foaming layer and the barrier layer are disposed between the TPU base layer and the PU layer, and the foaming layer is disposed closer to the TPU base layer. The surface treatment layer is disposed on the surface of the PU layer facing away from the TPU base layer.

[0133] In one example, the functional layer includes a surface treatment layer and a tactile layer. The surface treatment layer and the tactile layer are disposed on the surface of the PU layer facing away from the TPU base layer, and the tactile layer is disposed closer to the PU layer.

[0134] In one example, the functional layer includes a foaming layer, a barrier layer, a surface treatment layer, and a tactile layer. The foaming layer and the barrier layer are disposed between the TPU base layer and the PU layer, and the foaming layer is disposed closer to the TPU base layer. The surface treatment layer and the tactile layer are disposed on the surface of the PU layer facing away from the TPU base layer, and the tactile layer is disposed closer to the PU layer.

[0135] It can be understood that when the synthetic leather further includes at least one functional layer among the foaming layer, the barrier layer, the surface layer, the surface treatment layer, and the tactile layer, each functional layer also has a preset laser engraving pattern area. After the preset laser engraving pattern area of each functional layer is laser engraved, a laser engraving mark corresponding to the laser engraving pattern of the TPU base layer is also formed.

[0136] Refer to Figure 1 and Figure 2 , the present application provides a synthetic leather 10, including:

[0137] A TPU base layer 100, on one side surface of which a laser pattern 110 is formed;

[0138] A PU layer 200, disposed on the side surface of the TPU base layer 100 where the laser pattern 110 is formed; a laser engraving mark 210 corresponding to the laser pattern 110 is formed on the PU layer 200; along the thickness direction of the synthetic leather 10, the orthographic projection of the laser pattern 110 facing the PU layer 200 falls within the laser engraving mark 210.

[0139] In this application, a PU layer 200 is provided on a TPU base layer 100. At this time, the synthetic leather 10 combines the high strength, high elasticity, soft touch, and good weather resistance of TPU, thereby improving the practical performance and application range of the synthetic leather 10. A laser pattern 110 is formed on the TPU base layer 100. Due to the thermoplasticity of the TPU material of the base layer, the TPU material will partially melt during the formation of the laser pattern 110 and re-solidify after melting. Therefore, a laser-engraved pattern 110 with a smooth surface can be formed on the TPU base layer 100, giving the synthetic leather 10 rich layers and a good visual effect. In addition, the laser pattern 110 on one side surface of the TPU base layer 100 cooperates with the corresponding laser engraving marks 210 on the PU layer 200, making the laser pattern 110 have a strong sense of three-dimensionality, a unique visual effect, and a rich texture.

[0140] In addition, the flexibility and elasticity of the TPU base layer 100 enable it to closely fit various shell materials such as plastic, metal, and glass when used to prepare the composite shell of an electronic device, thereby effectively overcoming the problems of corner wrinkles and easy delamination caused by poor adhesion of traditional base fabrics such as polyester cloth and fiberglass cloth, and greatly improving the structural stability of the composite shell.

[0141] In one example, the TPU base layer 100 is one layer or multiple layers.

[0142] In one example, when the TPU base layer 100 is multiple layers, the TPU base layer 100 includes a first sub-layer, ……, and an Nth sub-layer stacked in a direction away from the PU layer 200; N is a positive integer ≥ 2. Exemplarily, the value of N includes but is not limited to 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0143] In one example, when the TPU base layer 100 is multiple layers; at least a laser-engraved pattern 110 is formed on the first sub-layer of the TPU base layer 100. It can be understood that in order to adapt to the preparation process steps of laser engraving, in the TPU base layer 100, the first sub-layer close to the PU layer 200 forms the laser-engraved pattern 110 first.

[0144] In one example, when the TPU base layer 100 is multiple layers, multiple laser patterns 110 are independently formed in each sub-layer of the TPU base layer 100.

[0145] In one example, in two adjacent sub-layers, the size of the laser pattern 110 of the sub-layer close to the PU layer 200 is not less than the size of the laser pattern 110 of the sub-layer away from the PU layer 200. It can be understood that in order to adapt to the preparation process steps of laser engraving, in the TPU base layer 100, the size of the laser-engraved pattern 110 of the first sub-layer close to the PU layer 200 is not less than the size of the laser-engraved pattern 110 of the sub-layer away from the PU layer 200.

[0146] Referring to Figure 3 , in one example, when the TPU base layer 100 is multi-layered, laser patterns 110 are formed on each sub-layer of the TPU base layer 100.

[0147] In one example, when the TPU base layer 100 is multi-layered, the sub-layers on which the multiple laser patterns 110 are formed are independently the same or different. It can be understood that the sub-layers in the TPU base layer 100 where the multiple laser patterns 110 are formed can be the same or different, that is, the depths of the laser patterns 110 are independently the same or different. The laser engraving process can reach different depths in each sub-layer at different positions. Referring to Figure 4 , the multiple laser patterns 110 are independently formed in each sub-layer of the TPU base layer 100.

[0148] Referring to Figure 5 , in one example, the multiple laser patterns 110 are independently formed in each sub-layer of the TPU base layer 100; and the size of the laser pattern 110 in the sub-layer closer to the PU layer 200 is not less than the size of the laser pattern 110 in the sub-layer farther from the PU layer 200.

[0149] In this application, the laser engraving pattern 110 is formed on the TPU base layer 100. The thermoplasticity of the TPU causes only partial melting of the surface of the TPU base layer 100. After cooling, the melted material on its surface re-solidifies, and thus a laser engraving pattern 110 with a smooth surface is formed. When the TPU base layer 100 is multi-layered and laser patterns 110 are formed on each sub-layer, and at the same time the size of the laser pattern 110 in the sub-layer closer to the PU layer 200 in adjacent sub-layers is not less than that in the sub-layer farther from the PU layer 200, as in Figure 5 , the laser engraving patterns can be independently formed in different sub-layers. At this time, through the progressive design of the sizes of the multi-layer patterns, a visual hierarchy with a stronger three-dimensional depth can be formed in the thickness direction of the synthetic leather 10, that is, the small-size pattern at the bottom layer serves as the base detail, and the large-size pattern on the upper layer forms the visual main body after being superimposed, making the laser engraving pattern present a three-dimensional look and feel. Moreover, the formation of the laser engraving patterns 110 on each of the above sub-layers conforms to the sequence of the laser engraving process, and has the advantages of convenient preparation and easy industrial production. At the same time, the multi-layer TPU structure enhances the interlayer adhesion through size nesting, avoiding the situation where the laser pattern 110 is damaged due to the fracture of a single TPU base layer 100, and strengthening the structural stability while improving the decoration.

[0150] In one example, in the TPU base layer 100, the color rendering properties of at least two adjacent sub-layers are different.

[0151] It can be understood that the color rendering property is any one of color, pearlescence, thermochromism, and fluorescence.

[0152] In one example, when the number of layers of the TPU base layer 100 is multiple, in the TPU masterbatch for preparing each sub-layer in the TPU base layer 100, the weight parts of the color masterbatch and / or pearlescent powder and / or thermochromic pigment and / or the rare earth fluorescent powder are different.

[0153] In another example, when the number of layers of the TPU base layer 100 is multiple, in the TPU masterbatch for preparing each sub-layer in the TPU base layer 100, the types of the color masterbatch and / or pearlescent powder and / or thermochromic pigment and / or the rare earth fluorescent powder are different.

[0154] There are obvious color rendering differences in the multi-layer structure of the TPU base layer 100. At this time, the laser engraving pattern 110 set on the TPU base layer 100 has high recognition, and the TPU base layer 100 can achieve the effect of multi-color gradient or multi-layer color rendering, thereby ensuring the visual effect and improving the sense of hierarchy.

[0155] In one example, the TPU base layer 100 is any one of a polyester-based polyurethane layer, a polyether-based polyurethane layer, and an aliphatic polyurethane layer.

[0156] In one example, the Shore hardness of the TPU base layer 100 is 60A to 90A. For example, the Shore hardness of the TPU base layer 100 includes but is not limited to 60A, 65A, 70A, 75A, 80A, 85A, or 90A, or within the range formed by any two of the above point values as the end point values.

[0157] The TPU base layer 100 with the above Shore hardness can better maintain its own structure during the formation of the laser engraving pattern 110, effectively avoiding the phenomenon that the pattern is incomplete due to being too hard to engrave, or the pattern edge melts and deforms due to being too soft, and reducing defects such as burrs and sawteeth, ensuring the complete and accurate presentation of the pattern. At the same time, the TPU base layer 100 with the above Shore hardness can also adjust the pressing touch of the entire synthetic leather 10 and enhance the user's use experience.

[0158] In one example, the antibacterial rate of the TPU base layer 100 is not less than 90%.

[0159] The TPU base layer 100 has antibacterial properties. On the one hand, it can provide a continuous antibacterial environment for the synthetic leather 10, which is beneficial to inhibiting the growth and reproduction of bacteria on the entire synthetic leather 10. On the other hand, when the TPU base layer 100 can effectively ensure that the synthetic leather 10 has antibacterial properties, it can avoid adding antibacterial agents to other surface functional layers such as the PU layer 200 at this time, thereby avoiding performance deterioration problems such as reduced gloss and damaged waterproof structure caused by adding antibacterial agents to the surface functional layer.

[0160] In one example, the flame retardancy of the TPU base layer 100 is not less than UL94V2 level.

[0161] Understandably, to make the TPU base layer 100 flame-retardant, a flame retardant can be added to the raw materials for preparing the TPU base layer 100. The TPU base layer 100 has flame retardancy, which can not only ensure the flame retardancy of the overall synthetic leather 20, but also avoid the performance deterioration such as the reduction of the flexibility of the surface functional layer and the decrease of the scratch resistance caused by the flame retardancy of other surface functional layers such as the PU layer 200.

[0162] In one example, the thickness of the TPU base layer 100 is 0.1 mm to 0.4 mm. In this application, since the laser engraving pattern is formed on one side surface of the TPU base layer 100, the thickness of the TPU base layer 100 plays an important role in preventing abnormal energy penetration and excessive ablation of materials during the laser engraving process and ensuring the integrity of the laser engraving pattern. Exemplarily, the thickness of the TPU base layer 100 includes but is not limited to 0.1 mm, 0.2 mm, 0.3 mm or 0.4 mm, or within the range formed by any two of the above point values as endpoint values.

[0163] In one example, the thickness of the synthetic leather 10 is 0.2 mm to 0.6 mm. When the thickness of the synthetic leather 10 is between 0.2 mm and 0.6 mm, it can not only ensure that the synthetic leather 10 has good flexibility and conformability, but also control the cost and reduce the overall weight of the product while ensuring strength and durability. Exemplarily, the thickness of the synthetic leather 10 includes but is not limited to 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm or 0.6 mm, or within the range formed by any two of the above point values as endpoint values.

[0164] In one example, the synthetic leather further includes a functional layer. The functional layer includes at least one of a foaming layer 300, a barrier layer 400, a surface layer 500, a surface treatment layer 600 and a touch layer 700.

[0165] The above functional layers are independently disposed on the surface of the PU layer 200 facing away from the TPU base layer 100, or between the PU layer 200 and the TPU base layer 100; and laser engraving marks 210 corresponding to the laser pattern 110 are formed on the functional layer.

[0166] Understandably, in this application, the materials of the foaming layer, the barrier layer, the surface layer, the surface treatment layer and the touch layer are not limited, as long as they can achieve the corresponding functions of buffering, barrier, decoration, touch optimization or surface protection.

[0167] Exemplarily, the material of the foaming layer includes but is not limited to foamed polyurethane resin. Further exemplarily, the foamed polyurethane resin includes but is not limited to polyester-based polyurethane, polyether-based polyurethane or polycarbonate-based polyurethane.

[0168] For example, the material of the barrier layer includes but is not limited to barrier polyurethane resin. For further example, the barrier polyurethane resin includes but is not limited to acrylate modified polyurethane barrier resin or polycarbonate barrier polyurethane resin.

[0169] For example, the material of the surface layer includes but is not limited to the surface layer polyurethane resin. For further example, the raw materials for preparing the surface layer include polyurethane prepolymer, vinyl-terminated polysiloxane, hydrogen-containing polysiloxane, reaction inhibitor, catalyst, silica, cyclic siloxane, polyisocyanate curing agent and compatibilizer. Among them, the polyurethane prepolymer is obtained by reacting polyol, terminal hydroxyl polysiloxane and polyisocyanate. The suitable hardness, softness and touch of the surface layer can simulate the texture of natural leather and improve the quality of synthetic leather. It is understandable that the present application does not limit the color of the surface layer, and the surface layer can present any color according to demand.

[0170] For example, the material of the surface treatment layer includes but is not limited to water-based aromatic polyurethane resin. For further example, the model of the water-based aromatic polyurethane resin is but is not limited to KTT728-7A. The surface treatment layer 600 can effectively keep the surface of the synthetic leather 10 clean and beautiful, while improving the anti-fouling property and easy cleaning property.

[0171] For example, the material of the touch layer includes but is not limited to polyurethane, silicone and polyolefin. The synthetic leather 10 containing the touch layer 700 has the advantages of being soft and smooth, excellent in elasticity, strong in weather resistance and not easy to be contaminated, which can significantly improve the texture and service life. Figure 6 In one example, the functional layer includes a foaming layer 300 and a barrier layer 400. The foaming layer 300 and the barrier layer 400 are disposed between the TPU base layer 100 and the PU layer 200, and the foaming layer 300 is disposed closer to the TPU base layer 100.

[0172] Please refer to this application Figure 7 In one example, the functional layer includes a surface treatment layer 600. The surface treatment layer 600 is disposed on a surface of the PU layer 200 that is away from the TPU base layer 100. It can be understood that the surface treatment layer 600 is a protective layer.

[0173] See also Figure 8 In one example, the functional layer includes a foaming layer 300, a barrier layer 400 and a surface treatment layer 600. The foaming layer 300 and the barrier layer 400 are disposed between the TPU base layer 100 and the PU layer 200, and the foaming layer 300 is disposed closer to the TPU base layer 100. The surface treatment layer 600 is disposed on the surface of the PU layer 200 facing away from the TPU base layer 100.

[0174] See also Figure 9, in one example, the functional layer includes a surface treatment layer 600 and a tactile layer 700. The surface treatment layer 600 and the tactile layer 700 are disposed on one side surface of the PU layer 200 facing away from the TPU base layer 100, and the tactile layer 700 is disposed closer to the PU layer 200.

[0175] See Figure 10 , in one example, the functional layer includes a foaming layer 300, a barrier layer 400, a surface treatment layer 600 and a tactile layer 700. Among them, the foaming layer 300 and the barrier layer 400 are disposed between the TPU base layer 100 and the PU layer 200, and the foaming layer 300 is disposed closer to the TPU base layer 100. The surface treatment layer 600 and the tactile layer 700 are disposed on one side surface of the PU layer 200 facing away from the TPU base layer 100, and the tactile layer 700 is disposed closer to the PU layer 200.

[0176] It can be understood that when the synthetic leather further includes at least one functional layer among the foaming layer, the barrier layer, the surface layer, the surface treatment layer and the tactile layer, each functional layer is also formed with a laser engraving mark corresponding to the laser engraving pattern of the TPU base layer, and the orthographic projection of the laser pattern 110 towards the functional layer falls within the laser engraving mark 210.

[0177] This application also provides an electronic device housing 1, including the synthetic leather 10 prepared by the preparation method of any one of the above examples of this application and a substrate layer 20, wherein the TPU base layer 100 is disposed close to the substrate layer 20.

[0178] In one example, the substrate layer is any one of a plastic layer, a fiber reinforced composite layer, a glass layer or a metal layer.

[0179] See Figure 11 , in one example, the electronic device housing 1 includes:

[0180] The TPU base layer 100, on one side surface of which a laser pattern 110 is formed;

[0181] The PU layer 200, disposed on one side surface of the TPU base layer 100 where the laser pattern 110 is formed; a laser engraving mark 210 corresponding to the laser pattern 110 is formed on the PU layer 200; along the thickness direction of the electronic device housing 1, the orthographic projection of the laser pattern 110 towards the PU layer 200 falls within the laser engraving mark 210;

[0182] The substrate layer 20, disposed on one side surface of the TPU base layer 100 facing away from the PU layer 200.

[0183] This application also provides a preparation method for an electronic device housing 1, including the following steps:

[0184] The synthetic leather 10 prepared by the preparation method of any example of the first aspect of the present application is compounded with the substrate layer 20, wherein the compounding methods include one or more of gluing, hot pressing and injection molding.

[0185] In one example, the substrate layer 20 is any one of a plastic layer, a fiber-reinforced composite layer, a glass layer or a metal layer.

[0186] Further exemplarily, the compounding method of the synthetic leather 10 and the plastic is gluing or injection molding.

[0187] The polarity of the TPU base layer 100 is similar to that of the plastic, so high-strength bonding can be achieved through gluing, and its interfacial bonding force is better than that of traditional textile substrates.

[0188] In addition, the compounding method of plastic materials such as TPU and thermoplastic elastomer TPE with the synthetic leather 10 can be injection molding. At this time, the synthetic leather 10 can be used as a pre-placed insert and directly combined with the molten TPU or TPE material in an injection mold to form an integrated seamless connection structure.

[0189] Further exemplarily, the compounding method of the synthetic leather 10 and the fiber-reinforced composite layer is hot pressing. The TPU base layer 100 has excellent elastic recovery ability and can be softened in the range of 120~180°C. It is convenient to be integrally cured and formed with fiber-reinforced composite layer materials such as epoxy / glass fiber semi-cured sheets through the hot pressing process, and the TPU base layer 100 can be quickly shaped after cooling, shortening the production cycle. At the same time, the finished product size of the electronic device housing prepared by hot pressing has good stability, is easy to be processed by CNC cutting, and can effectively avoid problems such as hair and silk.

[0190] The following further specific examples are used to illustrate the present application in detail. It should also be understood that the following examples are only used to further illustrate the present application and cannot be construed as limiting the protection scope of the present application. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present application all belong to the protection scope of the present application. The specific process parameters and the like in the following examples are also only an example within a suitable range, that is, those skilled in the art can make selections within a suitable range through the description in this article, and do not necessarily have to be limited to the specific values in the following examples.

[0191] Example 1

[0192] Example 1 of the present application provides a synthetic leather and its preparation method, including the following steps:

[0193] (1) Prepare the TPU masterbatch: By weight, the TPU masterbatch includes: 80 parts of TPU particles, 2 parts of lubricant (oleic acid amide), 2 parts of compatibilizer (maleic anhydride grafted polyolefin), 10 parts of red masterbatch, 5 parts of flame retardant (zirconium phosphate compounded with aluminum diethyl phosphinate), and 5 parts of antibacterial agent (chitosan).

[0194] (2) Preparation of the TPU base layer: Pre-dry each component of the TPU masterbatch at 70 °C for 5 h; then stir the TPU masterbatch at a rotation speed of 800 rpm for 10 min; then melt and extrude at a temperature of 200 °C to prepare the TPU base layer. Among them, the TPU base layer is single-layer, with a thickness of 0.1 mm, and the Shore hardness of the TPU base layer is 80A.

[0195] (3) Preparation of the synthetic leather matrix: Composite the TPU base layer with the PU layer by gluing to prepare the synthetic leather matrix. Among them, the thickness of the synthetic leather matrix is 0.2 mm.

[0196] (4) Laser engraving treatment: Take the surface of the PU layer away from the TPU base layer as the laser engraving surface, and perform laser engraving treatment on the preset laser engraving pattern area of the synthetic leather matrix until reaching the TPU base layer. The laser engraving depth is 0.13 mm. At this time, a laser engraving pattern is formed on the surface of the TPU base layer to prepare the synthetic leather. Among them, the process parameters of the laser engraving treatment include: the laser is ultraviolet light, the focal length is 170 mm, the speed is 150 mm / s, the current is 2 A, the frequency is 25 KHz, and the pulse width is 40 µs.

[0197] After observation, the laser engraving pattern formed on the surface of the TPU base layer of the synthetic leather is smooth, and shows a color different from that of the PU layer, with good visual effects. At the same time, the synthetic leather meets the ISO22196 standard with an antibacterial rate > 99%; and it can pass the UL94V0 level flame retardancy test.

[0198] Example 2

[0199] Embodiment 2 of the present application provides a synthetic leather and its preparation method, including the following steps:

[0200] (1) Prepare the TPU masterbatch for each sub-layer in the TPU base layer: Among them, the first TPU masterbatch includes 80 parts of TPU particles, 2 parts of lubricant (oleic acid amide), 2 parts of compatibilizer (maleic anhydride grafted polyolefin), and 5 parts of rare earth fluorescent powder. The second TPU masterbatch includes 80 parts of TPU particles, 2 parts of lubricant (oleic acid amide), 2 parts of compatibilizer (maleic anhydride grafted polyolefin), 10 parts of red masterbatch, 5 parts of flame retardant (zirconium phosphate compounded with aluminum diethyl phosphinate), and 5 parts of antibacterial agent (chitosan).

[0201] (2) Preparation of the TPU base layer: Pre-dry each component of the TPU masterbatch at 70 °C for 5 h; then stir the TPU masterbatch at a rotation speed of 800 rpm for 10 min; then melt and co-extrude at a temperature of 200 °C to prepare the TPU base layer. Among them, the TPU base layer has two layers, including a first TPU layer (with a thickness of about 0.05 mm) and a second TPU layer (with a thickness of about 0.05 mm) arranged in a stacked manner, with a total thickness of 0.1 mm, and the Shore hardness of the TPU base layer is 80A.

[0202] (3) Preparation of the synthetic leather substrate: Composite the TPU base layer with the PU layer by gluing. Among them, the first TPU layer is close to the PU layer to prepare the synthetic leather substrate. Among them, the thickness of the synthetic leather substrate is 0.2 mm.

[0203] (4) Laser engraving treatment: Take the surface of the side of the PU layer away from the TPU base layer as the laser engraving surface, and perform laser engraving treatment on the preset laser engraving pattern area of the synthetic leather substrate until reaching the TPU base layer. The laser engraving depth is 0.18 mm. At this time, a laser engraving pattern is formed on the surface of the TPU base layer to prepare the synthetic leather. Among them, the process parameters of the laser engraving treatment include: the laser is ultraviolet light, the focal length is 170 mm, the speed is 150 mm / s, the current is 2A, the frequency is 25KHz, and the pulse width is 40 µs.

[0204] After observation, the laser engraving pattern formed on the surface of the TPU base layer of the synthetic leather is smooth, and shows a color and fluorescence different from that of the PU layer, with good visual effects. At the same time, the synthetic leather meets the ISO22196 standard with an antibacterial rate > 99%; and it can pass the UL94V0 level flame retardancy test.

[0205] Example 3

[0206] Example 3 of this application provides a synthetic leather and its preparation method, including the following steps:

[0207] (1) Preparation of the TPU masterbatch: By weight, the TPU masterbatch includes: 100 parts of TPU particles, 2 parts of lubricant (oleic acid amide), and 2 parts of compatibilizer (maleic anhydride grafted polyolefin).

[0208] (2) Preparation of the TPU base layer: Pre-dry each component of the TPU masterbatch at 70 °C for 5 h; then stir the TPU masterbatch at a rotation speed of 800 rpm for 10 min; then melt and extrude at a temperature of 200 °C to prepare the TPU base layer. Among them, the TPU base layer is a single layer with a thickness of 0.1 mm, and the Shore hardness of the TPU base layer is 80A.

[0209] (3) Preparation of the synthetic leather substrate: The TPU base layer is laminated with the PU layer by gluing to prepare the synthetic leather substrate. The thickness of the synthetic leather substrate is 0.2 mm.

[0210] (4) Laser engraving treatment: Using the surface of the PU layer away from the TPU base layer as the laser engraving surface, laser engrave the preset laser engraving pattern area of the synthetic leather substrate until reaching the TPU base layer. The laser engraving depth is 0.13 mm. At this time, a laser engraving pattern is formed on the surface of the TPU base layer to prepare the synthetic leather. The process parameters of the laser engraving treatment include: the laser is ultraviolet light, the focal length is 170 mm, the speed is 150 mm / s, the current is 2 A, the frequency is 25 KHz, and the pulse width is 40 µs.

[0211] Observation shows that the laser engraving pattern formed on the surface of the TPU base layer of this synthetic leather is smooth and has a good visual effect. At the same time, this synthetic leather meets the ISO22196 standard with an antibacterial rate > 90%; and it can pass the UL94V2 level flame retardancy test.

[0212] Example 4

[0213] Example 4 of this application provides a synthetic leather and its preparation method, including the following steps:

[0214] (1) Preparation of the TPU masterbatch for each sub-layer in the TPU base layer: Among them, the first TPU masterbatch includes 80 parts of TPU particles, 2 parts of lubricant (oleic acid amide), 2 parts of compatibilizer (maleic anhydride grafted polyolefin), and 5 parts of rare earth fluorescent powder. The second TPU masterbatch includes 80 parts of TPU particles, 2 parts of lubricant (oleic acid amide), 2 parts of compatibilizer (maleic anhydride grafted polyolefin), 10 parts of red masterbatch, 5 parts of flame retardant (zirconium phosphate compounded with aluminum diethyl phosphinate), and 5 parts of antibacterial agent (chitosan).

[0215] (2) Preparation of the TPU base layer: Pre-dry each component of the TPU masterbatch at 70 °C for 5 h; then stir the TPU masterbatch at a rotation speed of 800 rpm for 10 min; then melt and co-extrude at a temperature of 200 °C to prepare the TPU base layer. The TPU base layer is two layers, including a first TPU layer (thickness about 0.05 mm) and a second TPU layer (thickness about 0.05 mm) arranged in a stacked manner, with a total thickness of 0.1 mm, and the Shore hardness of the TPU base layer is 80A.

[0216] (3)Preparation of the functional layer: Coat the one-side surface of the PU layer with a transparent barrier polyurethane slurry (including 100 parts of LT-50 resin, 0.5 part of wear-resistant additive DC-57, and 0.2 part of leveling agent BYK-333), and place it in an oven at 130 °C for drying to obtain the barrier layer. Coat the surface of the barrier layer with a thermosetting two-component foaming polyurethane slurry (prepared by mixing polyether-based component A and AL-5040B prepolymer in a weight ratio of 100:75. The polyether-based component A is prepared from the following components by weight: 95 parts of AL-3051A, 70 parts of aluminum hydroxide, 0.03 part of catalyst SJDT-12, and 0.5 part of water), and then place it in an oven at 90 °C for 1 min to form the foaming layer. Coat the other-side surface of the PU layer with a surface treatment agent (aqueous polyurethane treatment agent), and after baking at 150 °C for 5 min, it is formed into a surface treatment layer.

[0217] (4)Preparation of the synthetic leather substrate: The TPU base layer is laminated to the foaming layer in step (3) by gluing. Among them, the first TPU layer is close to the foaming layer to prepare the synthetic leather substrate. The thickness of the synthetic leather substrate is 0.3 mm. The synthetic leather substrate includes a surface treatment layer, a PU layer, a barrier layer, a foaming layer, a first TPU layer, and a second TPU layer arranged in layers.

[0218] (5)Laser engraving treatment: Take the one-side surface of the PU layer away from the TPU base layer as the laser engraving surface, and perform laser engraving treatment on the preset laser engraving pattern area of the synthetic leather substrate until reaching the TPU base layer. The laser engraving depth is 0.28 mm. At this time, a laser engraving pattern is formed on the surface of the TPU base layer to prepare the synthetic leather. Among them, the process parameters of the laser engraving treatment include: the laser is ultraviolet light, the focal length is 170 mm, the speed is 150 mm / s, the current is 2 A, the frequency is 25 KHz, and the pulse width is 40 µs.

[0219] Upon observation, the laser engraving pattern formed on the surface of the TPU base layer of the synthetic leather is smooth, and shows a different color and fluorescence from the PU layer, having a good visual effect. At the same time, the synthetic leather meets the ISO22196 standard with an antibacterial rate > 99%; and it can pass the UL94V0 level flame retardancy test.

[0220] The technical features of the above examples can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above examples are described. However, as long as the combinations of these technical features do not conflict, they should all be considered as the scope described in this specification.

[0221] The above examples only illustrate several implementation manners of the present application, which are convenient for understanding the technical solution of the present application specifically and in detail, but should not be construed as a limitation on the protection scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can be made, and these all belong to the protection scope of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided by the present application are all within the protection scope of the appended claims of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing synthetic leather, characterized in that It includes the following steps: Prepare a TPU masterbatch, process the TPU masterbatch to prepare a TPU base layer; Set a PU layer on one surface of the TPU base layer to prepare a synthetic leather substrate; Using the surface of the PU layer away from the TPU base layer as the laser engraving surface, perform laser engraving on the preset laser engraving pattern area of the synthetic leather substrate, and the laser engraving depth of the laser engraving treatment reaches the TPU base layer to prepare the synthetic leather.

2. The preparation method of the synthetic leather according to claim 1, characterized in that, The number of layers of the TPU base layer is one layer or multiple layers; Among them, when the number of layers of the TPU base layer is one layer, the steps of the laser engraving treatment include: using the surface of the PU layer away from the TPU base layer as the laser engraving surface, performing laser engraving on the preset laser engraving pattern area of the PU layer and the TPU base layer, and the laser engraving depth of the laser engraving treatment reaches the TPU base layer, and the laser engraving depth is less than the sum of the thicknesses of the PU layer and the TPU base layer and greater than the thickness of the PU layer; Or, when the number of layers of the TPU base layer is multiple layers, the TPU base layer includes a first sub-layer, ……, and an Nth sub-layer stacked along the direction away from the PU layer; N is a positive integer ≥2; the steps of the laser engraving treatment include: using the surface of the PU layer away from the TPU base layer as the laser engraving surface, performing laser engraving on the preset laser engraving pattern area of the PU layer and the TPU base layer, wherein at least the first sub-layer is included in the TPU base layer for the laser engraving treatment, and the total depth of the laser engraving treatment is less than the thickness of the synthetic leather substrate and greater than the thickness of the PU layer.

3. The method for preparing synthetic leather according to claim 1 or 2, characterized in that, The steps of processing the TPU masterbatch include stirring treatment, melting and forming treatment carried out in sequence; the steps of processing the TPU masterbatch have one or more of the following characteristics: (1) The process parameters of the stirring treatment include: the rotation speed is 600 rpm to 1000 rpm; (2) The process parameters of the melting include: the melting temperature is 180 °C to 220 °C; (3) Before the step of stirring the TPU masterbatch, a step of drying and pre-treating the TPU masterbatch is further included; (4) The thickness of the TPU base layer is 0.1 mm to 0.4 mm; (5) The Shore hardness of the TPU base layer is 60A to 90A; (6) The thickness of the synthetic leather substrate is 0.2 mm to 0.6 mm; (7) When the number of layers of the TPU base layer is one layer, the forming treatment method is calendering or extrusion; (8) When the number of layers of the TPU base layer is multiple layers, the forming treatment methods include one or more of calendering, gluing, laminating, hot pressing and co-extrusion; (9) The methods of setting the PU layer on one surface of the TPU base layer include one or more of gluing, laminating, hot pressing and co-extrusion.

4. The preparation method of the synthetic leather according to claim 1 or 2, characterized in that, When the number of layers of the TPU base layer is one layer or multiple layers, each of the TPU masterbatches independently includes the following components in parts by weight: 60 parts to 150 parts of TPU particles, 1 part to 3 parts of lubricant, and 1 part to 3 parts of compatibilizer; Among them, the TPU particles include one or more of polyester-based polyurethane particles, polyether-based polyurethane particles and aliphatic polyurethane particles.

5. The preparation method of the synthetic leather according to claim 4, characterized in that, The TPU masterbatch further includes: functional components; the functional components include one or more of color masterbatch, pearlescent powder, thermochromic pigment, and rare earth fluorescent powder; Among them, based on parts by weight, the TPU masterbatch includes 0.01 part to 15 parts of color masterbatch; Based on parts by weight, the TPU masterbatch includes 0.01 part to 15 parts of pearlescent powder; Based on parts by weight, the TPU masterbatch includes 0.01 part to 15 parts of thermochromic pigment; Based on parts by weight, the TPU masterbatch includes 0.01 part to 15 parts of rare earth fluorescent powder.

6. The method for preparing synthetic leather according to claim 5, wherein When the number of layers of the TPU base layer is multiple layers, in the TPU masterbatch for preparing each sub-layer in the TPU base layer, the parts by weight of the color masterbatch and / or the pearlescent powder and / or the thermochromic pigment and / or the rare earth fluorescent powder are different; Or, When the number of layers of the TPU base layer is multiple layers, in the TPU masterbatch for preparing each sub-layer in the TPU base layer, the categories of the color masterbatch and / or the pearlescent powder and / or the thermochromic pigment and / or the rare earth fluorescent powder are different.

7. The preparation method of the synthetic leather according to claim 4, characterized in that, Each of the TPU masterbatches independently further includes: a flame retardant; Among them, based on parts by weight, the TPU masterbatch includes 0.2 part to 15 parts of flame retardant.

8. The preparation method of the synthetic leather according to claim 4, wherein Each of the TPU masterbatches independently further includes: an antibacterial agent; Among them, based on parts by weight, the TPU masterbatch includes 0.3 part to 10 parts of antibacterial agent.

9. An electronic device housing, characterized in that, It includes a synthetic leather and a substrate layer, and the synthetic leather is the synthetic leather prepared by the preparation method according to any one of claims 1 to 8; Among them, the TPU base layer is disposed close to the substrate layer.

10. The electronic device housing according to claim 9, characterized in that, The substrate layer is any one of a plastic layer, a fiber reinforced composite layer, a glass layer, or a metal layer.

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