Component having multi-layer structure for interior trim of motor vehicle and method for production thereof

Abstract

The invention relates to a component having a multi-layer structure for an interior trim of a motor vehicle and to a method for producing the same. The component with the multi-layer structure sequentially comprises a wood veneer back glue layer, a wood veneer back glue layer and a wood veneer back glue layer, iI) a thermoplastic polyurethane film layer printed with ink; iII) a glass fiber reinforced polycarbonate base material layer; the flexible circuit film layer comprises a flexible electronic film, and a light-emitting device and a touch switch which are arranged on the flexible electronic film; and V) a back cover layer. The component with the multi-layer structure has self-luminous and touch functions, has wood texture and texture on the surface, and can be used as an automotive interior component.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile interior decoration components, and in particular to a component with a multi-layer structure for automobile interior decoration and a manufacturing method thereof. Background Art

[0002] The development of the household car market has led to the continuous improvement of the popularity of cars. As cars enter every household, people are becoming more and more familiar with cars. In addition to the engine, transmission and chassis as the core of the car, more and more consumers are beginning to pay attention to the appearance and interior parts of the car. Especially for interior parts, consumers have put forward higher requirements in terms of material functions.

[0003] With the rise of new energy vehicles, electronic and electrical applications are strongly promoting the development of the current automobile industry, and this trend is also more or less reflected in automobile interior decoration parts.

[0004] CN101376342A describes an interface for interior decoration components of motor vehicles, which includes a dashboard formed of a wooden board. The dashboard still uses a traditional backlight module, has a complex structure, is heavy, has switches arranged on the dashboard, and has no touch function, and cannot meet the diverse needs of customers for automotive interior decoration components.

[0005] CN106660242 A describes an in-film decoration of a film laminate substrate, including a cover substrate, a bottom substrate, an adhesive, a functional layer and a polymer resin connector formed into more than one part. The in-film decoration involves more connectors and a complex structure, so the process is also relatively complex.

[0006] CN110435074A relates to a method for manufacturing a molded product, including forming a solid wood layer on the surface of an injection molded product by using an in-film decoration (IMD) film provided with a solid wood stack. According to the method, an IMD film provided together with a solid wood stack can be manufactured on a release film, and the solid wood layer is formed on the surface of the injection molded product using the IMD film without breaking. However, the film product is basically an opaque material and does not meet the light transmission effect requirements.

[0007] There is no automotive interior component in the art that has self-luminous and touch functions, good surface texture, and simple processing technology. Summary of the invention

[0008] An object of the present invention is to provide an automobile interior decoration component having self-luminous and touch functions and good surface texture.

[0009] Another object of the present invention is to provide a method for producing an automotive interior component having self-luminous and touch functions and good surface texture, which has the characteristics of simple process.

[0010] According to one aspect, the present invention provides a component having a multilayer structure, characterized in that it comprises, in sequence:

[0011] I) a veneer adhesive layer having a light transmittance of more than 30%;

[0012] II) a thermoplastic polyurethane film layer printed with ink;

[0013] III) a glass fiber reinforced polycarbonate substrate layer having a light transmittance of more than 50%;

[0014] IV) a flexible circuit film layer, which includes a flexible electronic film, a light emitting device disposed on the flexible electronic film, and a touch switch; and

[0015] V) Back cover layer, its light transmittance is less than 3%,

[0016] The light transmittance is measured according to ASTM D1003-00.

[0017] According to another aspect, the present invention provides a method for manufacturing the above-mentioned component having a multilayer structure, characterized in that it comprises the following steps:

[0018] i) printing ink on a thermoplastic polyurethane film;

[0019] ii) laminating the veneer adhesive and the polyurethane film printed with ink to obtain a first assembly;

[0020] iii) fixing the first pressed part and the flexible circuit film on two opposite surfaces of the injection mold cavity respectively, injecting glass fiber reinforced polycarbonate melt for injection molding, and obtaining a second assembly; and

[0021] iv) The second assembly is fixed on one surface of the injection mold cavity, and a resin with a light transmittance of less than 3% is injected for injection molding to obtain a component with a multilayer structure.

[0022] The component with a multilayer structure of the present invention has self-luminescence and touch functions and a surface with wood grain and texture, and can be used as an automobile interior decoration component. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described and explained in more detail below in conjunction with the accompanying drawings, in which:

[0024] Figure 1A schematic diagram of the structure of a flexible circuit board is shown, wherein 11 represents a mounting protective layer; 12 represents a polycarbonate film; 13 represents a copper sheet film; 14 represents an LED lamp; and 15 represents a polyimide film.

[0025] Figure 2 It is an exploded view of the component with a multilayer structure prepared in Invention Example 1, wherein 21 in the figure represents a back cover; 22 represents a flexible circuit film; 23 represents a glass fiber reinforced polycarbonate substrate layer; 24 represents a TPU film printed with ink; and 25 represents a veneer adhesive layer.

[0026] Figure 3 The appearance of the automobile interior component having a multilayer structure prepared in Inventive Example 1 is shown. DETAILED DESCRIPTION

[0027] Certain specific embodiments of the invention will now be described in greater detail for purposes of illustration.

[0028] Components with multi-layer structures

[0029] According to one aspect, the present invention provides a component having a multilayer structure, characterized in that it comprises, in sequence:

[0030] I) a veneer adhesive layer having a light transmittance of more than 30%;

[0031] II) a thermoplastic polyurethane film layer printed with ink;

[0032] III) a glass fiber reinforced polycarbonate substrate layer having a light transmittance of more than 50%;

[0033] IV) a flexible circuit film layer, which includes a flexible electronic film, a light emitting device disposed on the flexible electronic film, and a touch switch; and

[0034] V) a back cover layer having a light transmittance of less than 3%,

[0035] The light transmittance is measured according to ASTM D1003-00.

[0036] Wood veneer adhesive layer

[0037] The component with a multi-layer structure of the present invention comprises a veneer adhesive backing layer.

[0038] The veneer adhesive backing layer is composed of a veneer facing sublayer and an adhesive fabric sublayer.

[0039] The veneer facing sub-layer may be formed of natural veneer or technological veneer.

[0040] As used in this application, technological veneer refers to veneer formed after natural wood fibers are artificially designed, arranged and dyed.

[0041] Therefore, the color of the veneer facing sub-layer can be a natural color or an artificially dyed color, preferably a light color.

[0042] Preferably, the thickness of the veneer facing sub-layer is in the range of 0.2 mm to 0.5 mm.

[0043] The veneer material has low shrinkage. At room temperature, the minimum longitudinal shrinkage of the veneer material is between 0.1-0.3%.

[0044] Preferably, the adhesive fabric sub-layer is a non-woven fabric layer impregnated with a thermosetting adhesive.

[0045] Preferably, the thickness of the adhesive fabric sub-layer is in the range of 0.2-0.7 mm.

[0046] Preferably, the thickness of the veneer adhesive layer is in the range of 0.3 mm to 1.2 mm.

[0047] Preferably, the adhesive fabric sublayer has a certain surface roughness, which helps to prevent the veneer adhesive layer and the thermoplastic polyurethane film layer from being relatively displaced during molding, thereby causing positioning deviation of the printed pattern.

[0048] Preferably, the surface roughness (Ra) is in the range of 10 μm to 100 μm, and the five-point average roughness of the surface is in the range of 10 μm to 80 μm.

[0049] The surface roughness (Ra) is the centerline average roughness specified in DIN ISO-4287, and the surface five-point average roughness is the five-point average roughness specified in DIN ISO-4287.

[0050] Thermoplastic polyurethane film layer printed with ink

[0051] The component with a multi-layer structure of the present invention comprises an ink-printed thermoplastic polyurethane (TPU) film layer in contact with an adhesive fabric sublayer of a veneer backing layer.

[0052] Preferably, the thickness of the ink-printed thermoplastic polyurethane (TPU) film (hereinafter referred to as TPU film) layer is in the range of 0.1 mm to 0.3 mm.

[0053] Preferably, one side of the ink-printed TPU film layer is printed by screen ink printing.

[0054] Printing texture or pattern can be freely designed according to requirements.

[0055] Preferably, the ink used for ink printing is PU ink.

[0056] The inventors have found that the presence of the TPU film layer can improve the warping degree of the component with a multi-layer structure, so that the warping degree becomes lower.

[0057] Glass fiber reinforced polycarbonate substrate layer

[0058] The component having a multilayer structure of the present invention includes a glass fiber reinforced polycarbonate (PC) substrate layer in contact with a thermoplastic polyurethane (TPU) film layer.

[0059] Preferably, the thickness of the glass fiber reinforced polycarbonate substrate layer is in the range of 2-8 mm.

[0060] The light transmittance of the glass fiber reinforced polycarbonate substrate layer is not less than 30%, preferably, in the range of 30-95%, tested according to standard ASTM D1003-00.

[0061] The inventors have found that a glass fiber reinforced polycarbonate substrate layer can reduce the warpage of the entire component having a multilayer structure.

[0062] Preferably, the amount of glass fiber is not less than 10 wt %, relative to the total weight of the glass fiber reinforced polycarbonate substrate layer.

[0063] More preferably, the amount of the glass fiber is in the range of 15-20 wt % relative to the total weight of the glass fiber reinforced polycarbonate substrate layer.

[0064] The inventors have also found that when the amount of glass fiber reaches 20 wt%, the resulting part having a multilayer structure has no significant visible haze.

[0065] Flexible circuit film

[0066] The component having a multi-layer structure of the present invention includes a flexible circuit film layer in contact with a glass fiber reinforced polycarbonate substrate layer.

[0067] Preferably, the thickness of the flexible circuit board is in the range of 0.3-0.7 mm.

[0068] The flexible circuit film layer has a hybrid structure, including a flexible electronic film, a light-emitting device arranged on the flexible electronic film, and a touch switch.

[0069] The light emitting device may be, for example, an LED lamp bead, the minimum thickness of which is 0.2 mm.

[0070] The touch switch may be, for example, a capacitive touch switch.

[0071] The flexible circuit board is commercially available and can be obtained from JuMing Technology Company.

[0072] Figure 1A schematic structural diagram of a flexible circuit film is shown, wherein 11 represents an LED lamp; 12 represents silica gel; 13 represents a copper film; 14 represents a polyimide (PI) film; and 15 represents a polycarbonate (PC) film.

[0073] Back cover

[0074] The component having a multi-layer structure of the present invention includes a back cover layer in contact with the flexible circuit film layer.

[0075] Preferably, the back cover is made of filler-reinforced polycarbonate alloy material.

[0076] Preferably, the filler is glass fiber or mineral powder.

[0077] The mineral powder may be, for example, talc.

[0078] The polycarbonate alloy material may be selected from polycarbonate / acrylonitrile-butadiene-styrene (PC / ABS) alloy materials, polycarbonate / styrene-acrylonitrile (PC / SAN) alloy materials, polycarbonate / polyester alloy materials and mixtures thereof.

[0079] The polyester may be, for example, polyethylene terephthalate.

[0080] Preferably, the content of the filler in the filler-reinforced polycarbonate alloy material is 10-30% by weight, relative to the total weight of the filler-reinforced polycarbonate alloy material.

[0081] Preferably, the content of polycarbonate in the filler-reinforced polycarbonate alloy material is 50-70% by weight, relative to the total weight of the filler-reinforced polycarbonate alloy material.

[0082] Preferably, the thickness of the back cover is in the range of 2mm-5mm.

[0083] The inventors found that the back cover made of filler-reinforced polycarbonate alloy material has better shrinkage resistance than unfilled polycarbonate alloy material, and can thereby improve the overall mechanical strength of components with a multi-layer structure, while also sealing the flexible circuit film layer to prevent the flexible circuit film layer from being impacted by external forces or eroded by water vapor.

[0084] The back cover may have parts for assembling components with a multi-layer structure, such as snaps and / or assembly screw columns.

[0085] The component with a multilayer structure of the present invention has self-luminous and touch functions and has a wood grain and texture on the surface, and can be used as an automotive interior component. In addition, the thermoplastic polyurethane (TPU) bonding wood veneer backing layer can improve the precise printing suitability and significantly reduce warping.

[0086] Method for manufacturing a component having a multilayer structure

[0087] According to another aspect, the present invention provides a method for manufacturing the above-mentioned component having a multilayer structure, characterized in that it comprises the following steps:

[0088] i) printing ink on a thermoplastic polyurethane film;

[0089] ii) laminating the veneer adhesive and the polyurethane film printed with ink to obtain a first assembly;

[0090] iii) fixing the first pressed part and the flexible circuit film on two opposite surfaces of the injection mold cavity respectively, injecting glass fiber reinforced polycarbonate melt for injection molding, and obtaining a second assembly; and

[0091] iv) The second assembly is fixed on one surface of the injection mold cavity, and a resin with a light transmittance of less than 3% is injected for injection molding to obtain a component with a multilayer structure.

[0092] The veneer adhesive used in the member having a multi-layer structure of the present invention can be obtained by self-processing or commercially available.

[0093] As a commercial example of veneer adhesive, there can be mentioned the one available from TABU under the trade name TABU R51.001L, which has a thickness of 0.5 mm, of which the veneer facing layer (dyed white veneer) has a thickness of 0.2 mm, and the adhesive fabric layer has a thickness of 0.3 mm. The average transmittance of the entire veneer adhesive in the visible light region (400nm-1030nm wavelength) is about 40%, and the maximum transmittance is 53.80% at a wavelength of 1030nm.

[0094] The polyurethane film used in the member having a multilayer structure of the present invention may be obtained by self-processing or may be commercially available.

[0095] As a commercial example of a polyurethane film, mention may be made of that available from Covestro as DESMOPAN 9390AU, which has a thickness of 0.2 mm.

[0096] Before printing ink, the surface of the polyurethane film is preferably cleaned, for example, by wiping the surface of the polyurethane film with toluene.

[0097] Before ink printing, the thermoplastic polyurethane film is preferably subjected to corona treatment to make the dyne value of the surface of the thermoplastic polyurethane film reach 40 dyne / cm or more.

[0098] Preferably, after the ink printing is performed, the polyurethane film is subjected to a drying process to dry the ink.

[0099] When the ink-printed polyurethane film is pressed onto the wood adhesive backing, the adhesive fabric sublayer of the wood adhesive backing contacts the polyurethane film.

[0100] Preferably, the ink-printed polyurethane film is pressed onto the wood backing at a temperature in the range of 170° C. to 190° C. and a pressure in the range of 10 bar to 20 bar.

[0101] More preferably, the ink-printed polyurethane film is pressed onto the wood backing adhesive by performing a first pressing for 2-3 minutes at a temperature in the range of 180°C-190°C and a pressure in the range of 10bar-15bar, and a second pressing for 3-5 minutes at a temperature in the range of 180°C-190°C and a pressure in the range of 15bar-20bar.

[0102] Preferably, the glass fiber reinforced PC resin is injection molded at a temperature in the range of 270° C.-310° C. and a pressure in the range of 80 bar-120 bar (hydraulic oil pressure).

[0103] During the molding process, the ink layer is between the adhesive fabric sublayer of the veneer backing layer and the TPU film. The ink layer does not directly contact the polycarbonate substrate melt under high temperature and high shear, which can avoid ink washout. The printed pattern remains clear and will not become blurred.

[0104] In some embodiments, the back cover is made of glass fiber reinforced PC / ABS alloy material.

[0105] In some embodiments, the back cover is made of glass fiber reinforced PC / SAN alloy material.

[0106] In some embodiments, the back cover is made of talc-reinforced PC / PET alloy material.

[0107] Preferably, glass fiber reinforced PC / ABS or talc reinforced PC / PET is injection molded at a temperature in the range of 270° C.-290° C. and a pressure in the range of 80-120 bar (hydraulic oil pressure).

[0108] The injection molding of the glass fiber reinforced polycarbonate substrate layer and the injection molding of the back cover can be performed in a double-shot injection mold through processes such as film insert injection molding and double-layer injection molding.

[0109] For example, the first assembly and the flexible circuit film are respectively fixed on two opposite surfaces of the first cavity of the double-shot injection mold, and the glass fiber reinforced PC substrate is injected into the mold cavity for injection molding. After the injection molding in the first cavity is completed, the mold and the flexible circuit film are separated to obtain the second assembly, and the mold is rotated so that the second assembly enters the second cavity, and the glass fiber reinforced PC / ABS alloy material, the glass fiber reinforced PC / SAN alloy material or the talc reinforced PC / PET is injected into the second cavity for injection molding to form a back cover, thereby obtaining a component with a multi-layer structure.

[0110] The back cover can be formed into parts for assembling multi-layer structural components, such as buckles and / or assembly screw columns, etc., by designing the mold.

[0111] The light transmittance described in this application is measured according to ASTM D1003-00. The light transmittance of the resin is measured using a sample with a thickness of 2 mm, while the light transmittance of each layer of a component having a multi-layer structure is directly measured on the corresponding layers.

[0112] The descriptions of various features in this application can be combined with each other if they are not contradictory, and the resulting technical solutions fall within the scope of protection requested by this application.

[0113] The terms “comprising” and “including” described in the present application encompass a case where the component is further comprised or includes other elements not explicitly mentioned as well as a case where the component is composed of the mentioned elements.

[0114] Unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which the invention belongs. When the definition of a term in this application conflicts with the meaning commonly understood by those skilled in the art to which the invention belongs, the definition described in this application shall prevail.

[0115] Unless otherwise indicated, all numerical values ​​used in this application to express thickness, size, processing conditions, etc. should be understood to be modified by the term "about". Therefore, unless otherwise indicated, the numerical values ​​set forth in this application are approximate values ​​that can vary depending on the desired properties to be obtained.

[0116] Example

[0117] The following will further illustrate the concept of the present invention and the technical effects produced in combination with the embodiments and drawings, so that those skilled in the art can fully understand the purpose, features and effects of the present invention. It is not difficult for those skilled in the art to understand that the embodiments herein are only for illustrative purposes, and the scope of the present invention is not limited thereto.

[0118] Raw materials used:

[0119] Veneer adhesive: purchased from TABU, with a thickness of 0.5mm, of which the veneer facing layer (dyed white veneer) is 0.2mm thick, and the adhesive fabric layer is 0.3mm thick. The average transmittance of the entire veneer adhesive in the visible light region (400nm-1030nm wavelength) is about 40%, and the maximum transmittance is 53.80% at a wavelength of 1030nm.

[0120] TPU film: obtained from Covestro, product brand DESMOPAN 9390AU, thickness 0.2 mm.

[0121] PU ink: from Imperial Ink, product brand INQ-HF.

[0122] Glass fiber reinforced PC resin: from Covestro, product grade MB.OM845G, with a glass fiber content of 20% by weight.

[0123] Glass fiber reinforced PC / SAN alloy material: from Covestro, the product grade is BB.T88GF20, in which the glass fiber content is 20% by weight, and the mass ratio of PC to SAN is 60:23.

[0124] Talc-reinforced PC / PET alloy material: from Covestro, with a talc content of 15% by weight and a weight ratio of PC to PET of 5:3.

[0125] Flexible circuit film: purchased from Juming Technology Co., Ltd., it includes LED lamp beads and flexible electronic film. The thickness of the flexible circuit board is about 0.5mm.

[0126] Invention Example 1

[0127] This embodiment provides a component having a multilayer structure comprising the following layers:

[0128] The first layer is the veneer adhesive layer.

[0129] The second layer is a TPU film printed with ink.

[0130] The third layer is a glass fiber reinforced polycarbonate substrate layer with a thickness of 7mm. Its visible light transmittance must be higher than that of the veneer facing layer to achieve the desired light transmission effect. The substrate layer has low shrinkage, with a shrinkage of 0.23% in the melt flow direction (measured in accordance with ISO 294-4) and a shrinkage perpendicular to the flow direction of 0.28% (measured in accordance with ISO294-4), and high light transmittance, with a visible light transmittance of 84% measured under a 2mm color plate (measured in accordance with ISO 13468-2).

[0131] The fourth layer is a flexible circuit film.

[0132] The fifth layer is an opaque back cover, which is made of glass fiber reinforced polycarbonate alloy material (PC / SAN) and has a thickness of 3 mm.

[0133] The component having a multilayer structure of this example was prepared as follows.

[0134] First, a TPU film layer printed with ink is provided as follows: before the ink is printed, the surface of the TPU film is wiped with toluene, and after the surface of the TPU film is cleaned and dried, corona treatment is performed to make the dyne value of the TPU surface reach more than 38 dynes / cm, PU ink is printed on the TPU surface, and the film is dried in an oven at 40°C for use.

[0135] The first pressing is performed at 180°C and 10 bar pressure for 2 minutes, and then at 180°C and 20 bar pressure for 5 minutes to laminate the TPU film printed with ink and the veneer adhesive to obtain the first assembly, wherein the side of the TPU film printed with ink is in contact with the adhesive fabric sublayer of the veneer adhesive. The first pressing is to pre-press the TPU film and the veneer adhesive for basic bonding. The pressure should not be too large to avoid rapid extension of the TPU film and blurring of the printed pattern on the TPU film. After the printed interface of the TPU film and the veneer adhesive form a good fit, a higher pressure is used to press out the air between the TPU film and the veneer adhesive to ensure the printed texture quality of the component and good adhesion between the TPU film and the veneer adhesive.

[0136] The surface of the fabric layer of the veneer adhesive is relatively rough. The original roughness data measured by the Hormel Idamik W10 surface roughness meter and the roughness after laminating with the ink-printed TPU film layer are shown in Table 1 below:

[0137] Table 1. Surface roughness

[0138]

[0139] R3Z(5) is the average value of the roughness depth R3Zi over five consecutive sampling lengths.

[0140] It can be seen from Table 1 that the surface roughness of the veneer adhesive is uneven, and the overall value is relatively high. The maximum Ra measured exceeds 66μm, and the minimum is not less than 10μm. This surface roughness is conducive to the bonding of the veneer adhesive and the TPU film. After the veneer adhesive and the TPU film are bonded, the surface roughness of the two-layer structure is greatly reduced. It can also be seen from Table 1 that the surface roughness of the first assembly obtained after bonding the TPU film is less than 1μm.

[0141] The first assembly and the flexible circuit film with LED lamp beads are fixed on the two opposite sides of the first cavity of the double-shot injection mold, respectively. The mold temperature of the side with the first assembly fixed is set to 75°C, and the mold temperature of the side with the flexible circuit film fixed is set to 65°C. Before fixing, the flexible circuit film is pre-shaped to facilitate better conformability of the flexible circuit film and the mold. The glass fiber reinforced PC substrate is injected into the mold cavity and injection molding is performed at 60°C.

[0142] Before injection into the mold cavity, the glass fiber reinforced PC substrate was dried at 110°C for 4 hours. The injection molding process parameters used in the first cavity are shown in Table 2:

[0143] Table 2. Injection molding process parameters of glass fiber reinforced PC substrate

[0144]

[0145]

[0146] After injection molding in the first cavity is completed, the mold and the flexible circuit film are separated to obtain a second assembly, and the mold is rotated so that the second assembly enters the second cavity, and the glass fiber reinforced PC / SAN alloy material is injected into the second cavity for injection molding to form a back cover, thereby obtaining a component with a multi-layer structure.

[0147] Before injection into the mold cavity, the glass fiber reinforced PC / SAN alloy material was dried at 110°C for 4 hours. The injection molding process parameters used in the second cavity are shown in Table 3:

[0148] Table 3. Injection molding process parameters of glass fiber reinforced PC / SAN alloy materials

[0149] Screw heating section 1 2 3 4 5 6 7 Hot runner temperature (℃) 285 285 285 285 285 285 285 Cylinder temperature (℃) 270 270 265 260 255 250 245 Screw position 1# 2# Injection pressure / position 110bar / 52mm 75bar / 22mm Holding pressure / time 35bar / 2s --

[0150] Figure 2 It is an exploded view of the component with a multilayer structure prepared in Invention Example 1, wherein 21 in the figure represents a back cover; 22 represents a flexible circuit film; 23 represents a glass fiber reinforced polycarbonate substrate layer; 24 represents an ink-printed TPU film; and 25 represents a veneer adhesive layer.

[0151] Figure 3 The appearance of the automobile interior component having a multilayer structure prepared in Inventive Example 1 is shown.

[0152] When the capacitive touch switch on the flexible printed circuit board is turned on, the LED lamp beads will light up and the light will reach the veneer veneer layer. Due to the light transmittance of the component with a multi-layer structure, the customized printed pattern can be clearly observed.

[0153] The component with a multilayer structure prepared by Inventive Example 1 has low warpage, clear ink printing patterns, and excellent light transmission effect.

[0154] In this application, the warpage of a component having a multilayer structure is evaluated as follows:

[0155] When the highest gap with the horizontal plane is less than 1 mm, the component with a multi-layer structure is considered to have low warpage; when the highest gap with the horizontal plane is greater than 1 mm, the component with a multi-layer structure is considered to have high warpage; when the highest gap with the horizontal plane is greater than 2 mm, the component with a multi-layer structure is considered to have very high warpage.

[0156] In this application, the light transmission effect is evaluated according to the following:

[0157] When the lighting effect and the switching of visible light can be clearly seen under a fluorescent lamp, the component with a multi-layer structure is considered to have an excellent light-transmitting effect; when the lighting effect can be seen under a fluorescent lamp, the component with a multi-layer structure is considered to have a good light-transmitting effect; when the lighting effect cannot be seen under a fluorescent lamp, the component with a multi-layer structure is considered to have a poor light-transmitting effect.

[0158] Invention Example 2

[0159] This embodiment is carried out with reference to the inventive embodiment 1, except that the back cover is made of a talc-reinforced polycarbonate alloy material. Specifically, the back cover is made of a PC / PET alloy material containing 15% talc, wherein the weight ratio of PC to PET is 5:3.

[0160] The component with a multi-layer structure obtained in this embodiment also has low warping, clear ink printing patterns and excellent light transmission effect.

[0161] Comparative Example 1

[0162] The structural difference between the multilayer structure component of this comparative example and the multilayer structure component of Inventive Example 1 is that the multilayer structure component does not have a TPU film layer.

[0163] During the processing, ink was printed on the adhesive fabric sublayer of the veneer backing layer using screen printing, and the other steps were the same as in Inventive Example 1.

[0164] The obtained multi-layer structure parts have a large warp, and the highest gap with the horizontal plane is up to 2mm. The ink printability under the veneer adhesive layer is poor. Since the veneer fibers have obvious orientation, the ink will crack as the veneer fibers bend. From the appearance of the multi-layer structure, the light transmission performance is excellent, the fineness of the pattern is also poor, and the light leakage is obvious.

[0165] Comparative Example 2

[0166] The difference in structure between the multilayer structure component of Comparative Example 2 and the multilayer structure component of Inventive Example 1 is that the third layer is a transparent polycarbonate substrate layer, and the substrate does not contain glass fibers.

[0167] The obtained multi-layer structural components have a large warpage, a maximum gap of up to 5mm with the horizontal plane, excellent light transmission performance, and high pattern fineness.

[0168] Comparative Example 3

[0169] The difference in structure between the multilayer structural component of Comparative Example 3 and the multilayer structural component of Inventive Example 1 is that there is no adhesive fabric sublayer, and the veneer facing is directly bonded to the ink-printed TPU film.

[0170] The resulting multilayer structural parts have low warpage, very poor printability, very blurry images, and poor light transmission.

[0171] Comparative Example 4

[0172] In this comparative example, a non-filled PC film printed with ink was used instead of a TPU film printed with ink to be combined with the veneer adhesive.

[0173] The results showed that the combination of non-filled PC film and wood veneer adhesive had high warping and was difficult to form a multi-layer structure.

[0174] Comparative Example 5

[0175] In this comparative example, a glass fiber reinforced PC film printed with ink was used instead of a TPU film printed with ink to be combined with the veneer adhesive.

[0176] The results showed that the glass fiber reinforced PC film and veneer adhesive had a high degree of warping after being combined, making it difficult to form a multi-layer structure. In addition, the PC film with glass fiber reinforced unidirectional tape and veneer adhesive also showed varying degrees of curling after hot pressing, making it difficult to achieve a multi-layer structure.

[0177] Comparative Example 6

[0178] In this comparative example, the ink is printed below the veneer adhesive layer, the second layer is a TPU film, and the other layers are the same as those in Invention Example 1.

[0179] The obtained multilayer structure has low warping and good light transmission, but there is slight ink bleeding and blurred patterns.

[0180] The components of each layer and their characteristics in the above invention examples and comparative examples are summarized in Table 4.

[0181]

Claims

1. A component having a multilayer structure, characterized in that: Including in order: I) a veneer adhesive layer having a light transmittance of more than 30%; II) a thermoplastic polyurethane film layer printed with ink; III) a glass fiber reinforced polycarbonate substrate layer having a light transmittance of more than 50%; IV) a flexible circuit film layer, which includes a flexible electronic film, a light emitting device disposed on the flexible electronic film, and a touch switch; and V) a back cover layer having a light transmittance of less than 3%, The light transmittance is measured according to ASTM D1003-00.

2. The component having a multilayer structure according to claim 1, characterized in that: The veneer adhesive backing layer is composed of a veneer facing sublayer and an adhesive fabric sublayer, and the adhesive fabric sublayer is in contact with the thermoplastic polyurethane film layer. Preferably, the thickness of the adhesive fabric sublayer is in the range of 0.2-0.7mm, and the thickness of the veneer adhesive backing layer is in the range of 0.3mm-1.2mm.

3. The component having a multilayer structure according to claim 2, characterized in that: The surface roughness (Ra) of the adhesive fabric sub-layer is in the range of 10 μm to 100 μm, and the five-point average surface roughness is in the range of 10 μm to 80 μm.

4. The component with a multilayer structure according to any one of claims 1 to 3, characterized in that: The thickness of the ink-printed thermoplastic polyurethane film layer is in the range of 0.1 mm to 0.3 mm.

5. The component with a multilayer structure according to any one of claims 1 to 4, characterized in that: The thickness of the glass fiber reinforced polycarbonate substrate layer is in the range of 2-8 mm, and preferably, the amount of glass fiber is not less than 10 wt %, preferably in the range of 15-20 wt %, relative to the total weight of the glass fiber reinforced polycarbonate substrate layer.

6. The component with a multilayer structure according to any one of claims 1 to 5, characterized in that: The thickness of the flexible circuit film layer is in the range of 0.3-0.7 mm.

7. The component with a multilayer structure according to any one of claims 1 to 6, characterized in that: The thickness of the back cover layer is in the range of 2mm-5mm. Preferably, the back cover layer is made of a filler-reinforced polycarbonate alloy material. Preferably, the filler is glass fiber or mineral powder. Preferably, the polycarbonate alloy material can be selected from polycarbonate / acrylonitrile-butadiene-styrene (PC / ABS) alloy material, polycarbonate / styrene-acrylonitrile (PC / SAN) alloy material, polycarbonate / polyester alloy material and a mixture thereof.

8. A method for manufacturing a component having a multilayer structure according to any one of claims 1 to 7, characterized in that: The following steps are involved: i) printing ink on a thermoplastic polyurethane film; ii) laminating the veneer adhesive and the polyurethane film printed with ink to obtain a first assembly; iii) fixing the first pressed part and the flexible circuit film on two opposite surfaces of the injection mold cavity respectively, injecting glass fiber reinforced polycarbonate melt for injection molding, and obtaining a second assembly; and iv) The second assembly is fixed on one surface of the injection mold cavity, and a resin with a light transmittance of less than 3% is injected for injection molding to obtain a component with a multilayer structure.

9. The method according to claim 8, characterized in that Before ink printing, the thermoplastic polyurethane film is first subjected to corona treatment to make the dyne value of the surface of the thermoplastic polyurethane film reach more than 40 dyne / cm.

10. The method according to claim 8 or 9, characterized in that: The ink-printed polyurethane film is pressed onto the wood backing at a temperature in the range of 170°C-190°C and a pressure in the range of 10 bar-20 bar.

11. The method according to claim 8 or 9, characterized in that: The ink-printed polyurethane film is pressed onto the wood backing adhesive by performing a first pressing for 2-3 minutes at a temperature in the range of 170°C-190°C and a pressure in the range of 10-15 bar, and a second pressing for 3-5 minutes at a temperature in the range of 170°C-190°C and a pressure in the range of 15 bar-20 bar.

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