A PMMA composite sheet with built-in wiring harness and a manufacturing method thereof

Abstract

The present application relates to a PMMA composite sheet with embedded wiring harness, comprising a sheet body and at least one wiring harness embedded in the sheet body; the projection of the wiring harness on the first plane is linear, and the first plane is the plane where the length direction and width direction of the composite sheet are located; the wiring harness comprises a core layer, a skin layer covering the core layer, and an intermediate layer between the core layer and the skin layer, and the peel strength between the skin layer and the sheet body is greater than the peel strength between the skin layer and the intermediate layer; and / or, the wiring harness comprises a core layer and a skin layer covering the core layer, and the peel strength between the skin layer and the sheet body is greater than the peel strength between the skin layer and the core layer. The present application improves the yield and impact resistance of the PMMA composite sheet with embedded wiring harness by embedding a wiring harness of a multi-layer structure in the sheet body and utilizing the difference in peel strength between different layers; and the wiring harness is linearly distributed in the sheet, which can enhance the overall structural strength of the composite sheet, avoid the generation of a large number of fragments after the sheet is hit, and improve safety in use.

Description

Technical Field

[0001] The present application relates to the technical field of composite sheet materials, and in particular to a wire harness embedded PMMA composite sheet material and a manufacturing method thereof. Background Art

[0002] Polymethyl methacrylate (PMMA), as a transparent polymer material with excellent comprehensive performance, has been widely used in rail transit sound insulation barriers, transparent / insulated curtain walls of high-rise buildings, aircraft cockpit covers, deep-sea detector windows, etc. Specifically, taking high-speed rail or urban rail transit noise reduction facilities as an example, if PMMA sheets of a specific thickness are used alone as the main material of the sound barrier, there are dual hidden dangers in terms of traffic safety and ecological environment. The former is reflected in the fact that the hard and brittle PMMA material is prone to produce a large number of fragments after being hit, endangering the safety of nearby pedestrians and vehicles; the latter mainly considers that birds find it difficult to identify highly transparent PMMA sheets, thus causing the risk of accidental collision. Summary of the invention

[0003] In response to the above technical problems, the present application provides a wiring harness embedded PMMA composite sheet and a manufacturing method thereof, which can enhance the overall structural strength of the composite sheet, avoid the generation of a large amount of fragments after the sheet is impacted, and improve safety of use.

[0004] In order to solve the above technical problems, the present application provides a PMMA composite sheet with embedded wiring harness, comprising a sheet body and at least one wiring harness embedded in the sheet body; the projection of the wiring harness on the first plane is linear, and the first plane is the plane where the length direction and width direction of the composite sheet are located; the wiring harness comprises a core layer, a skin layer covering the core layer, and an intermediate layer between the core layer and the skin layer, and the peel strength between the skin layer and the sheet body is greater than the peel strength between the skin layer and the intermediate layer; and / or, the wiring harness comprises a core layer and a skin layer covering the core layer, and the peel strength between the skin layer and the sheet body is greater than the peel strength between the skin layer and the core layer.

[0005] Optionally, in the length direction of the wire harness, the cross-sectional area of ​​the wire harness changes alternately, and / or the cross-sectional shape of the wire harness is at least one of a circle, a triangle, a polygon or an ellipse.

[0006] Optionally, the surface of the skin layer has a geometric pattern, and / or the skin layer has a porous structure.

[0007] Optionally, the peel strength between the skin layer and the board body is greater than or equal to 50 MPa; the peel strength between the skin layer and the middle layer is less than or equal to 25 MPa, and / or the peel strength between the skin layer and the core layer is less than or equal to 25 MPa.

[0008] Optionally, the thickness of the core layer is less than or equal to 5 mm, the thickness of the middle layer is 0.01-2 mm, and the thickness of the skin layer is greater than or equal to 0.5 mm.

[0009] The present application also provides a method for manufacturing a wiring harness embedded PMMA composite sheet, which is used to manufacture the composite sheet as described above, comprising the following steps:

[0010] Provide molds;

[0011] Providing a wiring harness, the wiring harness comprising a core layer, a skin layer covering the core layer, and an intermediate layer located between the core layer and the skin layer, and / or the wiring harness comprising a core layer and a skin layer covering the core layer;

[0012] Fixing at least one wire harness in the mold so that the projection of the wire harness on the plane where the mold is located is linear;

[0013] pouring a polymer precursor for forming a sheet body into a mold to wrap the wire harness;

[0014] Curing polymer precursors;

[0015] Demoulding to obtain a composite board.

[0016] Optionally, the polymer precursor includes polymethyl methacrylate, methyl methacrylate, a functional monomer and an initiator, wherein the functional monomer is used to form a chemical bond between the skin layer and the board body.

[0017] Optionally, a wiring harness is provided, comprising at least one of the following:

[0018] When extruding the skin layer, a geometric pattern is formed on the surface of the skin layer using an extrusion port having a preset outlet shape;

[0019] After the wire harness is extruded, the surface of the wire harness is subjected to sandblasting and / or chemical etching;

[0020] Adding a template material for forming a porous structure into the extruded material of the skin layer, and removing the template material after extruding to form a wire bundle, so as to form a skin layer with a porous structure;

[0021] An inert solvent is added to the extruded material of the skin layer and extruded to form a wire bundle, wherein the inert solvent and the polymer precursor can be dissolved in each other, and the refractive index of the inert solvent is close to the refractive index of the plate body.

[0022] Optionally, before curing the polymer precursor, the manufacturing method further comprises:

[0023] The mixture of polymer precursor and strands is allowed to stand for a preset time.

[0024] Optionally, a wiring harness is provided, comprising:

[0025] The skin layer is extruded by a variable speed stretching method so that the cross-sectional area of ​​the harness changes alternately in the length direction of the harness.

[0026] The wire-harness embedded PMMA composite sheet of the present application includes a sheet body and at least one wire harness embedded in the sheet body; the projection of the wire harness on the first plane is linear, and the first plane is the plane where the length direction and width direction of the composite sheet are located; the wire harness includes a core layer, a skin layer covering the core layer, and an intermediate layer between the core layer and the skin layer, and the peel strength between the skin layer and the sheet body is greater than the peel strength between the skin layer and the intermediate layer; and / or, the wire harness includes a core layer and a skin layer covering the core layer, and the peel strength between the skin layer and the sheet body is greater than the peel strength between the skin layer and the core layer. The present application simultaneously improves the yield and impact resistance of the wire-harness embedded PMMA composite sheet by embedding a wire harness with a multi-layer structure in the sheet body and utilizing the difference in peel strength between different layers; and the wire harness is linearly distributed in the sheet, which can enhance the overall structural strength of the composite sheet, avoid the generation of a large number of fragments after the sheet is hit, and improve safety in use.

[0027] The manufacturing method of the PMMA composite sheet with embedded wiring harness of the present application includes the following steps: providing a mold; providing a wiring harness, the wiring harness including a core layer, a skin layer covering the core layer, and an intermediate layer between the core layer and the skin layer, and / or the wiring harness including a core layer and a skin layer covering the core layer; fixing at least one wiring harness in the mold so that the projection of the wiring harness on the plane where the mold is located is linear; pouring a polymer precursor for forming the sheet body in the mold to wrap the wiring harness; curing the polymer precursor; demolding to obtain a composite sheet. The present application embeds a wiring harness with a multi-layer structure in the sheet body, and the wiring harness is linearly distributed in the sheet, which can enhance the overall structural strength of the composite sheet, avoid the generation of a large number of fragments after the sheet is hit, and improve the safety of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is one of the three-dimensional schematic diagrams of the PMMA composite sheet with embedded wiring harness according to the first embodiment.

[0029] Figure 2 This is the second stereoscopic schematic diagram of the PMMA composite sheet with embedded wiring harness according to the first embodiment.

[0030] Figure 3 It is one of the perspective stereoscopic schematic diagrams of the PMMA composite sheet with embedded wiring harness according to the first embodiment.

[0031] Figure 4 This is the second perspective stereoscopic schematic diagram of the PMMA composite sheet with embedded wiring harness according to the first embodiment.

[0032] Figure 54 is a schematic cross-sectional view of a PMMA composite sheet material with embedded wiring harness according to the first embodiment.

[0033] Figure 6 is one of the schematic cross-sectional views of the wire harness according to the first embodiment.

[0034] Figure 7 This is a second schematic cross-sectional view of the wire harness according to the first embodiment.

[0035] Figure 8 This is a third cross-sectional schematic diagram of the wire harness according to the first embodiment.

[0036] Fig. 9 It is a schematic flow chart of a method for manufacturing a PMMA composite sheet material with embedded wiring harness according to a second embodiment.

[0037] Fig.10 1 is a schematic diagram of a mold for manufacturing a PMMA composite sheet with embedded wiring harness according to the second embodiment.

[0038] Fig.11 It is a schematic diagram showing the impact strength test results of the composite board according to the first embodiment. DETAILED DESCRIPTION

[0039] The following is an explanation of the implementation of the present application by means of specific embodiments. People familiar with the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification.

[0040] In the following description, reference is made to the accompanying drawings, which describe several embodiments of the present application. It should be understood that other embodiments may be used and that mechanical, structural, electrical, and operational changes may be made without departing from the spirit and scope of the present application. The following detailed description should not be considered limiting, and the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0041] Although the terms first, second, etc. are used herein to describe various elements in some instances, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element.

[0042] Furthermore, as used in this article, the singular forms "one", "an" and "the" are intended to include plural forms as well, unless there is an indication to the contrary in the context. It should be further understood that the terms "comprise", "include" indicate the presence of the described features, steps, operations, elements, components, projects, kinds, and / or groups, but do not exclude the presence, occurrence or addition of one or more other features, steps, operations, elements, components, projects, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Therefore, "A, B or C" or "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". Exceptions to this definition will only occur when the combination of elements, functions, steps or operations is inherently mutually exclusive in some way.

[0043] First embodiment

[0044] like Figures 1 to 4 As shown, the wire-harness embedded PMMA composite sheet of the present application comprises a sheet body 200 and at least one wire harness 100 embedded in the sheet body 200. The projection of the wire harness 100 on the first plane is linear, and the first plane is the plane where the length direction and width direction of the composite sheet are located.

[0045] like Figure 2 and Figure 4 As shown, the wiring harness 100 includes a core layer 103, a skin layer 101 covering the core layer 103, and an intermediate layer 102 located between the core layer 103 and the skin layer 101, and / or Figure 1 and Figure 3 As shown, the wire harness 100 includes a core layer 103 and a skin layer 101 covering the core layer 103 .

[0046] In the composite sheet of the present application, the sheet body 200 is the main part of the composite sheet and is made of PMMA material, so that the composite sheet has excellent transparency and certain structural strength. One or more wire harnesses 100 are embedded in the sheet body 200. The projection of the wire harness 100 on the plane where the length direction and width direction of the sheet body 200 are located is linear, that is, the wire harness 100 runs through the sheet body 200 in a linear path, which can effectively disperse the vertical stress acting on the composite sheet. At the same time, when the sheet is hit and a large number of fragments are generated, a dragging effect is generated, thereby reducing the splashing of fragments or the falling of large pieces.

[0047] Optionally, a plurality of wire harnesses 100 are embedded in the sheet body 200, the wire harnesses 100 are parallel to the first plane, and the wire harnesses 100 are parallel to each other. The wire harnesses 100 may be arranged in parallel at intervals along the length direction or width direction of the sheet body 200, or may be arranged in parallel along other directions parallel to the first plane. Figure 5As shown, the wire harness 100 is arranged at the center of the thickness direction of the plate body 200, and is distributed in parallel with equal spacing along the length direction or width direction of the plate body 200, that is, α1=α2 and β1=β2. The diameter of the wire harness 100 is preferably 2-7.5 mm, and the arrangement spacing of the wire harness 100 is preferably 5-30 cm.

[0048] The wiring harness 100 has a multi-layer structure, which may be two layers and / or three layers, or more than three layers. Figure 1 , Figure 3 and Figure 6 As shown, the wiring harness 100 includes a core layer 103 and a skin layer 101 covering the core layer 103. Figure 2 , Figure 4 , Figure 7 and Figure 8 As shown, the wire harness 100 includes a core layer 103, a skin layer 101 covering the core layer 103, and an intermediate layer 102 located between the core layer 103 and the skin layer 101. The cross section of the wire harness 100 is a concentric structure.

[0049] The outermost skin layer 101 is used to protect the inner core layer 103 and / or the middle layer 102 from the external environment, such as preventing water intrusion, chemical erosion or mechanical damage. The core layer 103 is used to provide the overall mechanical strength of the wire harness 100. The middle layer 102 is located between the skin layer 101 and the core layer 103 and is used to improve the tensile strength and flexibility of the wire harness 100. Figure 7 The intermediate layer 102 shown is a transition layer formed of a specific type of polymer. Figure 8 The intermediate layer 102 shown is a braided layer, which is braided from multiple strands of fibers. Both the transition layer and the braided layer can enhance the mechanical strength of the wire harness 100 .

[0050] The peel strength between the skin layer 101 and the sheet body 200 is greater than the peel strength between the skin layer 101 and the middle layer 102 ; and / or, the peel strength between the skin layer 101 and the sheet body 200 is greater than the peel strength between the skin layer 101 and the core layer 103 .

[0051] The core layer 103 and the middle layer 102, as well as the middle layer 102 and the skin layer 101, are made of mutually compatible materials with good compatibility and bonding strength. The peel strength between the core layer 103 and the middle layer 102, as well as between the middle layer 102 and the skin layer 101, is greater than 5 MPa.

[0052] Optionally, for the wiring harness 100 with a three-layer structure, the peel strength between the cortex 101 and the sheet body 200 is greater than or equal to 50MPa, and the peel strength between the cortex 101 and the middle layer 102 is less than or equal to 25MPa. For the wiring harness 100 with a two-layer structure, the peel strength between the cortex 101 and the sheet body 200 is greater than or equal to 50MPa, and the peel strength between the cortex 101 and the core layer 103 is less than or equal to 25MPa. The peel strength between the cortex 101 and the sheet body 200 is sufficiently high (i.e., ≥50MPa), which enhances the overall bonding force between the wiring harness 100 and the sheet body 200. The peel strength between the core layer 103 and the middle layer 102, and between the middle layer 102 and the cortex 101 is suitably high (i.e., >5MPa), which can ensure the stability and reliability of the internal structure of the wiring harness 100 during use. Under the action of vertical external force, since the peel strength between the cortex 101 and the sheet body 200 is greater than or equal to 50MPa, it can be ensured that the energy is first fully absorbed along the surface of the harness, the impact resistance is exerted as much as possible, and the separation time between the harness 100 and the sheet body 200 is delayed. Combined with the peel strength between the cortex 101 and the middle layer 102 being less than or equal to 25MPa, and / or the peel strength between the cortex 101 and the core layer 103 being less than or equal to 25MPa, when the energy is large, the impact energy can be further absorbed by destroying the internal structure of the harness, thereby improving the overall impact resistance of the sheet.

[0053] The wire harness 100 can be obtained by an extrusion process. The extrusion process refers to passing the raw material through an extrusion port of a specific shape under the action of heat and pressure to form a product with a continuous length. The wire harness 100 can also be obtained by combining one or more of the dipping, spraying, and deposition processes, or the extrusion process is combined with one or more of the dipping, spraying, and deposition processes to prepare the wire harness 100.

[0054] For example, when the wire harness 100 is a skin layer 101-core layer 103 structure composed of two materials, a co-extrusion process can be used to simultaneously realize the extrusion of the wire harness 100 of the skin layer 101-core layer 103 structure. Alternatively, a wire harness of one material (as the core layer 103) is first obtained by an extrusion process, and then one or more of the processes of dipping, spraying, and deposition are used to form a coated skin layer 101 on its periphery. When the wire harness 100 is a skin layer 101-intermediate layer 102-core layer 103 composed of three materials, the intermediate layer 102 is selected as a braided layer. When preparing the wire harness 100, a wire harness of one material (as the core layer 103) can be obtained by an extrusion process, and then the core layer 103 enters a braiding device to form a braided layer on its periphery, and then a third material is formed on the outer layer of the braided layer 102 by an extrusion process. At this time, the third material will pass through the pores of the braided layer and enter the inside of the braided layer, thereby covering the braided layer, showing the effect of the braided layer embedded in the skin layer. At this time, the thickness of the braided layer will not affect the thickness of the entire wire harness. After cooling, the braided layer 102 is fixed inside and introduced as a reinforcement to further improve the overall strength of the wire harness 100. When the wire harness uses a skin layer 101-intermediate layer 102-core layer 103 of three materials, the intermediate layer 102 selects a transition layer, which is formed by at least one layer of polymer material. When preparing the wire harness 100, a material wire harness (as the core layer 103) can be obtained through an extrusion process, and then the core layer 103 enters the extrusion equipment, and the transition layer and the skin layer 101 are extruded on the surface of the core layer 103 at the same time. At this time, the thickness of the transition layer will affect the overall thickness of the wire harness 100.

[0055] Optionally, in the length direction of the wire harness 100 , the cross-sectional area of ​​the wire harness 100 changes alternately, and / or the cross-sectional shape of the wire harness 100 is at least one of a circle, a triangle, a polygon or an ellipse.

[0056] Optionally, in the process of forming the wire harness 100 by an extrusion process, the morphology of the material can be changed by adjusting the stretching speed. Specifically, by controlling the stretching speed of the extruded wire harness 100, the wire harness 100 can be stretched to different degrees in different time periods. For example, keeping the extrusion process unchanged, speeding up the stretching speed at a certain stage will make the wire harness thinner, while slowing down the speed at another stage will make it relatively thicker. By means of variable speed stretching, the diameter of the formed wire harness 100 changes along its length, that is, the cross-sectional area of ​​the wire harness 100 changes alternately, and the change can be periodic. The non-uniform diameter wire harness 100 can increase the contact area with the plate body 200, enhance the mechanical bonding between the two and the anti-pull performance in the length direction of the wire harness.

[0057] Optionally, the cross-sectional shape of the wiring harness 100 can be at least one of a circle, a triangle, a polygon or an ellipse. Among them, the circular cross-section and the ellipse cross-section have uniform or relatively uniform stress distribution characteristics and can effectively resist external pressure and tension. The triangular cross-section has good mechanical stability and compression resistance. The polygonal cross-section can increase the contact area with the plate body 200 and improve the bonding strength.

[0058] Optionally, the surface of the skin layer 101 has a geometric pattern. When the skin layer 101 is extruded, an extrusion port with a preset outlet shape (i.e., a die with a specific inner wall geometric structure) can be used, and / or an irregular additional molding pressure can be applied to the extruded material, so that the material forms a corresponding pattern according to a predetermined mode while being extruded, thereby forming a geometric pattern on the surface of the skin layer 101, such as lines, dots, patterns, etc., to increase the surface area of ​​the skin layer 101 and improve the contact area between the skin layer 101 and the plate body 200.

[0059] Optionally, after the wire harness 100 is extruded, the surface of the wire harness 100 is sandblasted and / or chemically corroded, or a parallel wire groove structure is constructed on the surface of the cortex 101 to increase the surface area of ​​the cortex 101 and improve the contact area between the cortex 101 and the plate body 200.

[0060] Optionally, the cortex 101 is a porous structure. The porous structure increases the contact area between the cortex 101 and the sheet body 200, and enhances the bonding strength. In addition, in the composite sheet, microchannels that laterally penetrate the surface of the cortex 101 can be formed between the pores of the porous structure. During the molding process of the sheet body 200, these microchannels are first infiltrated and filled with the polymer precursor that forms the sheet body 200 and then subsequently cured, thereby further improving the interfacial bonding force. Specifically, during the formation of the wire harness 100, a template material for forming a porous structure is added to the extruded material of the cortex 101. After the wire harness 100 is extruded to form the wire harness 100, the wire harness 100 is placed in an aqueous solution or an acid solution to remove the template material, thereby forming a cortex 101 having a porous structure.

[0061] The template material can be a water-soluble particle, including one or more of sodium chloride, potassium chloride, sodium nitrate, and potassium nitrate. The template material can also be an acid-reactive particle, including one or more of iron, aluminum, calcium carbonate, aluminum oxide, magnesium carbonate, potassium carbonate, and sodium carbonate. The size range of the template material is 0.1 to 10 μm, and the appearance morphology can include one or more of sphere, rod, olive, cube, or other regular geometric shapes.

[0062] Optionally, the extruded material of the cortex 101 is doped with an inert solvent, and the inert solvent and the polymer precursor solvent (i.e., MMA monomer) forming the sheet body 200 can be mutually soluble, preferably DBP (dibutyl phthalate) or DOP (dioctyl phthalate). During the curing (or polymerization) process of the polymer precursor, the inert solvent in the cortex 101 and the MMA monomer diffuse with each other to achieve the exchange of substances in space. As the polymerization reaction proceeds, MMA is gradually converted into PMMA, and the area where the polymerization occurs will also expand from the outside of the cortex 101 to the inside of the cortex 101 where the inert solvent originally existed, so that a mutually embedded interface is formed between the cortex 101 and the sheet body 200. In this way, the contact area between the cortex 101 and the sheet body 200 is significantly increased, thereby greatly enhancing the bonding strength between the two.

[0063] It should be noted that the refractive index of the inert solvent should be close to that of the sheet body 200. Preferably, the absolute value of the difference between the refractive index of the inert solvent and the sheet body 200 is ≤0.5. The inert solvent is dissolved in the polymer precursor that forms the sheet body and then undergoes a curing reaction. The close refractive index enables the formed composite sheet to maintain good light transmittance. In addition, the inert solvent does not participate in the polymerization reaction of MMA, that is, it does not chemically react with the MMA monomer.

[0064] Optionally, the heat shrinkage of the material of the skin layer 101, the middle layer 102 and the core layer 103 matches the material of the board body 200. Preferably, the difference between the heat shrinkage of the material of the skin layer 101 or the middle layer 102 or the core layer 103 and the heat shrinkage of the board body 200 is less than 10%.

[0065] The bending properties of the skin layer 101 and the core layer 103 are similar. Preferably, the difference in the flexural deformation of the skin layer 101 relative to the core layer 103 is less than 10%.

[0066] The skin layer 101 and the core layer 103 have the same color, specifically black, brown, gray, or other colors that are easily identifiable by birds.

[0067] The chemical properties of the material used for the skin layer 101 are similar to those of the plate body 200. After the MMA polymerization reaction is completed, an excellent bonding force is formed between the skin layer 101 and the plate body 200.

[0068] Optionally, the material of the core layer 103 is at least one of nylon 6, nylon 66, modified nylon 6, modified nylon 66, ultra-high molecular weight polyethylene, and modified ultra-high molecular weight polyethylene. The material of the skin layer 101 is at least one of polyvinyl chloride, acrylic resin, anhydride-modified polyvinyl chloride, and anhydride-modified acrylic resin. When the middle layer 102 is a transition layer, its material is at least one of anhydride-modified PE, anhydride-modified PP, and anhydride-modified EVA.

[0069] Optionally, the thickness of the core layer 103 is less than or equal to 5 mm, the thickness of the middle layer 102 is 0.01-2 mm, and the thickness of the skin layer 101 is greater than or equal to 0.5 mm. When the middle layer 102 is a braided layer, the monofilament material of the braided layer can be one of polyester, nylon, spandex, polypropylene, aramid, glass fiber, carbon fiber, and metal wire.

[0070] The wire-harness embedded PMMA composite sheet of the present application includes a sheet body and at least one wire harness embedded in the sheet body; the projection of the wire harness on the first plane is linear, and the first plane is the plane where the length direction and width direction of the composite sheet are located; the wire harness includes a core layer, a skin layer covering the core layer, and an intermediate layer between the core layer and the skin layer, and the peel strength between the skin layer and the sheet body is greater than the peel strength between the skin layer and the intermediate layer; and / or, the wire harness includes a core layer and a skin layer covering the core layer, and the peel strength between the skin layer and the sheet body is greater than the peel strength between the skin layer and the core layer. The present application simultaneously improves the yield and impact resistance of the wire-harness embedded PMMA composite sheet by embedding a wire harness with a multi-layer structure in the sheet body and utilizing the difference in peel strength between different layers; and the wire harness is linearly distributed in the sheet, which can enhance the overall structural strength of the composite sheet, avoid the generation of a large number of fragments after the sheet is hit, and improve safety in use.

[0071] Second embodiment

[0072] Fig. 9 FIG. 2 is a flow chart of a method for manufacturing a PMMA composite sheet material with embedded wiring harness according to a second embodiment. Fig. 9 As shown, the manufacturing method of the wire harness embedded PMMA composite sheet of the present application is used to manufacture the wire harness embedded PMMA composite sheet as described in the first embodiment, comprising:

[0073] Step S1. Providing a mold.

[0074] like Fig.10 As shown, a casting mold 800 for manufacturing a PMMA composite sheet embedded with a wiring harness is shown. In the casting mold 800, a parallel through hole 815 is centrally provided in the plastic frame 810 for passing the wiring harness 100. After the wiring harness 100 passes through the through hole 815, the side edges of the plastic frame 810 are exposed at both ends. The casting mold 800 includes a plastic frame 810, an upper template 820 and a lower template 830. The plastic frame 810 is sandwiched between the upper template 820 and the lower template 830 to form a cavity together. The size design of the parallel through hole 815 can achieve an interference fit with the wiring harness 100 to ensure a tight connection.

[0075] Step S2. Provide a wiring harness, wherein the wiring harness comprises a core layer, a skin layer covering the core layer, and an intermediate layer between the core layer and the skin layer, and / or the wiring harness comprises a core layer and a skin layer covering the core layer.

[0076] The wiring harness has a multi-layer structure, which may be two layers and / or three layers, or more than three layers. Optionally, a strip-shaped core layer is obtained. A skin layer is formed on the surface of the core layer to obtain a wiring harness with a two-layer structure. Alternatively, a strip-shaped core layer is obtained; an intermediate layer is formed on the surface of the core layer; and a skin layer is formed on the surface of the intermediate layer to obtain a wiring harness with a three-layer structure.

[0077] The cross section of the harness is a concentric structure. The outermost cortex is used to protect the inner core layer and / or middle layer from the external environment, such as preventing moisture intrusion, chemical erosion or mechanical damage. The core layer is used to provide the overall mechanical strength of the harness. The middle layer is located between the cortex and the core layer and is used to improve the tensile strength and flexibility of the harness. The middle layer can be a transition layer formed by a specific type of polymer or a braided layer. The braided layer is woven from multiple strands of fibers. Both the transition layer and the braided layer can enhance the mechanical strength of the harness.

[0078] The peel strength between the skin layer and the body of the sheet is greater than the peel strength between the skin layer and the middle layer; and / or the peel strength between the skin layer and the body of the sheet is greater than the peel strength between the skin layer and the core layer.

[0079] Optionally, for a wiring harness with a three-layer structure, the peel strength between the cortex and the sheet body is greater than or equal to 50MPa, and the peel strength between the cortex and the middle layer is less than or equal to 25MPa. For a wiring harness with a two-layer structure, the peel strength between the cortex and the sheet body is greater than or equal to 50MPa, and the peel strength between the cortex and the core layer is less than or equal to 25MPa. The peel strength between the cortex and the sheet body is sufficiently high (i.e., ≥50MPa), which enhances the overall bonding strength between the wiring harness and the sheet body. The peel strength between the core layer and the middle layer, and between the middle layer and the cortex is suitably high (i.e., >5MPa), which can ensure the stability and reliability of the internal structure of the wiring harness during use. Under the action of vertical external force, since the peel strength between the cortex and the sheet body is greater than or equal to 50MPa, it can be ensured that the energy is first fully absorbed along the surface of the harness, and the impact resistance is exerted as much as possible and the separation between the harness and the sheet body is delayed. Combined with the peel strength between the cortex and the middle layer being less than or equal to 25MPa, and / or the peel strength between the cortex and the core layer being less than or equal to 25MPa, when the energy is large, the impact energy can be further absorbed by destroying the internal structure of the harness, thereby improving the overall impact resistance of the sheet.

[0080] The wire harness can be obtained by extrusion process. Extrusion process refers to the process of passing raw materials through a specific shape of extrusion port under the action of heat and pressure to form a product with continuous length. The wire harness can also be obtained by combining one or more of the dipping, spraying, and deposition processes, or by combining the extrusion process with one or more of the dipping, spraying, and deposition processes to prepare the wire harness.

[0081] For example, when the wiring harness is a cortex-core structure composed of two materials, a co-extrusion process can be used to simultaneously realize the extrusion of the wiring harness of the cortex-core structure. Alternatively, a wiring harness of a material (as a core layer) is first obtained by an extrusion process, and then one or more of the processes of dipping, spraying, and deposition are used to form a coated cortex on its periphery. When the wiring harness is a cortex-middle layer-core layer of three materials, a braided layer is selected for the middle layer. When preparing the wiring harness, a wiring harness of a material (as a core layer) can be obtained by an extrusion process, and then the core layer enters the braiding equipment to form a braided layer on its periphery, and then the third material is formed on the outer layer of the braided layer through an extrusion process. At this time, the third material will pass through the pores of the braided layer and enter the interior of the braided layer, thereby coating the braided layer, presenting the effect of the braided layer embedded in the cortex. At this time, the thickness of the braided layer will not affect the overall thickness of the wiring harness. After cooling, the braided layer is fixed inside and introduced as a reinforcement to further improve the overall strength of the wiring harness.

[0082] When the wiring harness adopts a skin layer-middle layer-core layer of three materials, the middle layer selects a transition layer, which is formed by a layer of polymer. When preparing the wiring harness, a material wiring harness (as a core layer) can be obtained by an extrusion process, and then the core layer enters the extrusion equipment, and the transition layer and the skin layer are extruded on the surface of the core layer at the same time. At this time, the thickness of the transition layer will affect the overall thickness of the wiring harness.

[0083] Optionally, a wiring harness is provided, comprising at least one of the following:

[0084] When extruding the skin layer, a geometric pattern is formed on the surface of the skin layer using an extrusion port having a preset outlet shape;

[0085] After the wire harness is extruded, the surface of the wire harness is subjected to sandblasting and / or chemical etching;

[0086] Adding a template material for forming a porous structure into the extruded material of the skin layer, and removing the template material after extruding to form a wire bundle, so as to form a skin layer with a porous structure;

[0087] An inert solvent is added to the extruded material of the skin layer and extruded to form a wire bundle, wherein the inert solvent and the polymer precursor solvent (ie, MMA monomer) are mutually soluble, and the refractive index of the inert solvent is close to that of the sheet body.

[0088] Optionally, the surface of the skin layer has a geometric pattern. When the skin layer is extruded, an extrusion port with a preset outlet shape may be used, and / or an irregular additional molding pressure may be applied to the extruded material, so that the material forms a corresponding pattern according to a predetermined mode while being extruded, thereby forming a geometric pattern on the surface of the skin layer, such as lines, dots, patterns, etc., to increase the surface area of ​​the skin layer and improve the contact area between the skin layer and the plate body.

[0089] Optionally, after the wire harness is formed by extrusion, the surface of the wire harness is sandblasted and / or chemically corroded, or a parallel wire groove structure is constructed on the surface of the skin layer to increase the surface area of ​​the skin layer and improve the contact area between the skin layer and the plate body.

[0090] Optionally, the cortex is a porous structure. The porous structure increases the contact area between the cortex and the body of the sheet, and enhances the bonding strength. In addition, in the composite sheet, microchannels that laterally penetrate the surface of the cortex can be formed between the pores of the porous structure. During the molding process of the sheet body, these microchannels are first infiltrated and filled with the polymer precursor that forms the sheet body and then subsequently cured, further improving the interfacial bonding strength. Specifically, during the process of forming the wire harness, a template material for forming a porous structure is added to the extruded material of the cortex. After the wire harness is formed by extrusion, the wire harness is placed in an aqueous solution or an acid solution to remove the template material to form a cortex with a porous structure.

[0091] The template material can be a water-soluble particle, including one or more of sodium chloride, potassium chloride, sodium nitrate, and potassium nitrate. The template material can also be an acid-reactive particle, including one or more of iron, aluminum, calcium carbonate, aluminum oxide, magnesium carbonate, potassium carbonate, and sodium carbonate. The size range of the template material is 0.1 to 10 μm, and the appearance morphology can include one or more of sphere, rod, olive, cube, or other regular geometric shapes.

[0092] Optionally, the extruded material of the cortex is doped with an inert solvent, and the inert solvent and the polymer precursor solvent (i.e., MMA monomer) that forms the body of the sheet can be mutually soluble, preferably DBP (dibutyl phthalate) or DOP (dioctyl phthalate). During the curing (or polymerization) process of the polymer precursor, the inert solvent and MMA diffuse with each other to achieve the exchange of substances in space. As the polymerization reaction proceeds, MMA is gradually converted into PMMA, and the area where the polymerization occurs will also expand from the outside of the cortex to the inside of the cortex containing the inert solvent, so that a mutually embedded interface is formed between the cortex and the body of the sheet. In this way, the contact area between the cortex and the body of the sheet is significantly increased, thereby improving the bonding strength between the two.

[0093] It should be noted that the refractive index of the inert solvent is close to that of the sheet body. Preferably, the absolute value of the difference between the refractive index of the inert solvent and that of the sheet body is ≤0.5. After the inert solvent is dissolved in the polymer precursor forming the sheet body and undergoes a curing reaction, the close refractive index enables the formed composite sheet to maintain good light transmittance. In addition, the inert solvent does not participate in the polymerization reaction of MMA.

[0094] Optionally, a wiring harness is provided, comprising:

[0095] The skin layer is extruded by a variable speed stretching method so that the cross-sectional area of ​​the harness changes alternately in the length direction of the harness.

[0096] In the process of forming the wire harness by the extrusion process, the morphology of the material can be changed by adjusting the stretching speed. Specifically, by controlling the stretching speed of the extruded wire harness 100, the wire harness can be stretched to different degrees in different time periods. For example, keeping the extrusion process unchanged, speeding up the stretching speed at a certain stage will make the wire harness thinner, while slowing down the speed at another stage will make it relatively thicker. By means of variable speed stretching, the diameter of the formed wire harness changes along its length, that is, the cross-sectional area of ​​the wire harness changes alternately, and the change can be periodic. The non-equal diameter wire harness can increase the contact area with the sheet body, enhance the mechanical bonding between the two and the anti-pull performance in the length direction of the wire harness.

[0097] Step S3. Fix at least one wire harness in the mold so that the projection of the wire harness on the plane where the mold is located is linear.

[0098] At least one harness is fixed in the mold so that one or more harnesses are embedded in the sheet body. The projection of the harness on the plane where the length and width directions of the sheet body are located is linear, that is, the harness runs through the sheet body in a linear path, which can effectively disperse the vertical stress acting on the composite sheet. At the same time, when the sheet is hit by the outside and a large number of fragments are generated, a dragging effect is generated, thereby reducing the splashing of fragments or the falling of large pieces.

[0099] Step S4: pouring a polymer precursor for forming a sheet body into a mold to wrap the wiring harness.

[0100] Optionally, the polymer precursor includes polymethyl methacrylate, methyl methacrylate, a functional monomer and an initiator, wherein the functional monomer is used to form a chemical bond between the skin layer and the board body.

[0101] Optionally, the material composition ratio of the polymer precursor can be that the mass proportion of polymethyl methacrylate is 5-20%, the mass proportion of the initiator is ≤1%, the functional monomer is ≤5%, and the rest is methyl methacrylate. The initiator is selected from at least one of BPO, AIBN, ABVN, methyl vinyl ketone, benzoin, dimethylbenzene, fluorescein, and eosin, that is, a single initiator or a combination of initiators can be selected.

[0102] Optionally, when the harness cortex contains anhydride, selecting functional monomers with end groups of epoxy and unsaturated bonds (such as allyl glycidyl ether or 4-hydroxybutyl acrylate glycidyl ether) can effectively promote chemical grafting between the cortex and the sheet body to form a stable grafting structure. In order to achieve the best reaction effect, it is necessary to control the viscosity of the precursor to keep it within an appropriate range (for example, the viscosity of 4 cups of coating at 25°C is less than 150s) to ensure that the functional monomers can fully penetrate and evenly distribute to form a composite material with stable performance.

[0103] Step S5: solidifying the polymer precursor.

[0104] After the polymer precursor is heated and cured, the sheet body is formed, which can maintain the state of wrapping the wire harness and form a composite structure of the mold and the sheet. The heating process can be divided into two stages: the first stage is the low-temperature stage: heating at 50-65°C for 2-72 hours. The second stage is the high-temperature stage: heating at 100-135°C for 1-12 hours. In this way, the curing polymerization process can be better controlled and production efficiency can be improved.

[0105] Optionally, before curing the polymer precursor, the mold of the polymer precursor wrapped wire harness is left to stand for a preset time. If the wire harness contains an inert solvent in its cortex, it is left to stand for at least 1 hour before starting curing, i.e. before entering the low temperature stage, so that the inert solvent and the polymer precursor can fully exchange substances.

[0106] Step S6: demoulding to obtain a composite board.

[0107] After removing the mold, the composite board can be obtained.

[0108] For the specific structure and function of the PMMA composite sheet with embedded wiring harness manufactured by the manufacturing method of the PMMA composite sheet with embedded wiring harness in this embodiment, please refer to the relevant description of the first embodiment, which will not be repeated here.

[0109] The following lists different implementation processes of the manufacturing method according to this embodiment:

[0110] Process 1

[0111] The thickness of the PMMA composite sheet embedded in the manufactured wiring harness is 15 mm.

[0112] The material composition ratio of the polymer precursor is 5-15% by mass of polymethyl methacrylate, ≤1% by mass of the initiator, ≤5% by mass of the functional monomer, and the rest is methyl methacrylate, and the initiator is ABVN. At the end of step S1, a polymer precursor with a viscosity characteristic of 80-120s (25°C) is formed with a 4-cup flow time. The functional monomer is specifically allyl glycidyl ether, which accounts for 5% by mass. By adjusting the ratio of polymethyl methacrylate and methyl methacrylate, the 4-cup viscosity of the final polymer precursor is controlled to be 100s.

[0113] The skin-core structure is made of two materials. The skin material is acrylic resin, and the core material is nylon 66. The linear material of nylon 66 (as the core layer) is obtained by extrusion process in advance, and then the desired acrylic resin coating layer is formed on the periphery of the core layer by extrusion process again. The core layer thickness is 2mm, and the skin layer thickness is 0.5mm.

[0114] After the plastic frame (the wire harnesses used have been inserted into the parallel through holes in sequence) has been nested and locked with the lower template of the casting mold, the upper template is covered on it, and the fasteners lock the mold around.

[0115] The polymerization process includes, in sequence, a low-temperature stage of a water bath or a forced air bath at 45 to 65° C. for 2 to 72 hours, and a high-temperature stage of a forced air bath at 95 to 125° C. for 1 to 12 hours.

[0116] The specific polymerization process adopts 60°C water bath / 24h, and then 125°C air blowing / 3h.

[0117] Craft 2

[0118] The difference from process 1 is that the skin layer material is PVC resin, the core layer material is modified nylon 66, and the rest remain the same.

[0119] Craft 3

[0120] Different from process 1, a skin layer-transition layer-core layer structure with three materials is used. The skin layer material is anhydride-modified acrylic resin, the core layer material is nylon 66, and the transition layer is anhydride-modified EVA. The linear material of nylon 66 (as the core layer) is obtained in advance through the extrusion process, and then the transition layer and the skin layer are extruded simultaneously on the surface of the core layer using the extrusion process again. The core layer thickness is 2mm, the skin layer thickness is 0.3mm, the transition layer thickness is 0.2mm, and the rest are the same.

[0121] Craft 4

[0122] Different from process 3, the skin layer material is anhydride modified PVC resin, the core layer material is modified nylon 66, the transition layer is anhydride modified PE, and the rest remain the same.

[0123] Craft 5

[0124] Different from process 1, a skin layer-braided layer-core layer structure with three materials is adopted. The skin layer material is anhydride modified acrylic resin, the core layer material is modified nylon 66, the braided layer material is carbon fiber with a thickness of about 0.25mm, the core layer thickness is 2mm, the skin layer thickness is 0.5mm, and the rest are consistent.

[0125] Control group

[0126] Using existing technology (sheet thickness 15mm), the wiring harness is made of a single material of nylon 66 with an outer diameter of 2.5mm. The polymerization process is consistent with process 1.

[0127] Sample preparation and result analysis

[0128] The composite sheets obtained from process 1 to process 5 and the control group were subjected to the wet heat cycle test mode according to the provisions of GB / T 12000-2017 "Determination of the effects of exposure of plastics to moisture, heat, water spray and salt fog". The upper limit temperature was 55°C and the test was repeated for 6 24h cycles. The key indicators are shown in Table 1. It can be clearly seen that the composite sheets provided by process 1 to process 5 did not have any separation of the wire harness. However, in the control group, the areas on both sides of the wire harness were obviously separated from the PMMA, extending from the edge to the inside, with obvious air ingress, and whitening along the wire harness to the circumference. There were wire harness detachment sections with lengths ranging from 1 to 5 cm on both sides of each wire harness.

[0129] Table 1. Statistics of wet heat aging test results

[0130]

[0131] In addition, this application also characterizes the simple supported beam unnotched impact strength of the composite sheet in accordance with GB / T 1043.1-2008 "Determination of impact properties of plastics - Part 1: Non-instrumented impact test". For the composite sheet formed by process 1 to process 5 and the control group, the sample preparation for the impact strength test was carried out: the test samples all contained wire bundles, and the wire bundles were all centered. Fig.11 The unnotched simply supported beam impact strength results shown in the figure show that the impact strength of the samples in process 1 to process 5 ranges from 72.1 to 93.6 kJ / m 2 , while the control group was only 52.3~61.8kJ / m 2 , which means that the wire harness adopts a two-material cortex-core structure, a three-material cortex-transition layer-core structure, or a cortex-braided layer-core structure, and its impact resistance is significantly higher than that of a single-material wire harness.

[0132] From the above, the technical solution proposed in this application achieves excellent bonding between the wire harness and the sheet body (i.e., PMMA matrix) without adding any acid etching agent that is not conducive to the final demolding, solves the problem of whitening and fogging along the edge of the wire harness caused by the entry of air due to the separation of the two, and effectively breaks through the technical barriers that hinder the further development of the PMMA composite sheet manufacturing field.

[0133] The manufacturing method of the PMMA composite sheet with embedded wiring harness of the present application includes the following steps: providing a mold; providing a wiring harness, the wiring harness including a core layer, a skin layer covering the core layer, and an intermediate layer between the core layer and the skin layer, and / or the wiring harness including a core layer and a skin layer covering the core layer; fixing at least one wiring harness in the mold so that the projection of the wiring harness on the plane where the mold is located is linear; pouring a polymer precursor for forming the sheet body in the mold to wrap the wiring harness; curing the polymer precursor; demolding to obtain a composite sheet. The present application embeds a wiring harness with a multi-layer structure in the sheet body, and the wiring harness is linearly distributed in the sheet, which can enhance the overall structural strength of the composite sheet, avoid the generation of a large number of fragments after the sheet is hit, and improve the safety of use.

[0134] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A PMMA composite sheet with embedded wiring harness, characterized in that: It includes a plate body and at least one wiring harness embedded in the plate body; The projection of the wire bundle on the first plane is linear, and the first plane is the plane where the length direction and the width direction of the composite sheet are located; The wiring harness includes a core layer, a skin layer covering the core layer, and an intermediate layer located between the core layer and the skin layer, and the peel strength between the skin layer and the sheet body is greater than the peel strength between the skin layer and the intermediate layer; and / or, the wiring harness includes a core layer and a skin layer covering the core layer, and the peel strength between the skin layer and the sheet body is greater than the peel strength between the skin layer and the core layer.

2. The composite sheet material according to claim 1, characterized in that: In the length direction of the wire harness, the cross-sectional area of ​​the wire harness changes alternately, and / or the cross-sectional shape of the wire harness is at least one of a circle, a triangle, a polygon or an ellipse.

3. The composite sheet material according to claim 1, characterized in that: The surface of the skin layer has a geometric pattern, and / or the skin layer is a porous structure.

4. The composite sheet material according to claim 1, characterized in that: The peel strength between the skin layer and the plate body is greater than or equal to 50 MPa; The peel strength between the skin layer and the middle layer is less than or equal to 25 MPa, and / or the peel strength between the skin layer and the core layer is less than or equal to 25 MPa.

5. The composite sheet material according to claim 1, characterized in that: The thickness of the core layer is less than or equal to 5 mm, the thickness of the middle layer is 0.01-2 mm, and the thickness of the skin layer is greater than or equal to 0.5 mm.

6. A method for manufacturing a PMMA composite sheet with embedded wiring harness, characterized in that: The method for manufacturing the composite board according to any one of claims 1 to 5 comprises the following steps: Provide molds; Providing a wiring harness, the wiring harness comprising a core layer, a skin layer covering the core layer, and an intermediate layer located between the core layer and the skin layer, and / or the wiring harness comprising a core layer and a skin layer covering the core layer; Fixing at least one of the wire harnesses in the mold so that the projection of the wire harness on the plane where the mold is located is linear; pouring a polymer precursor for forming a sheet body into the mold to wrap the wiring harness; curing the polymer precursor; Demoulding to obtain a composite board.

7. The method according to claim 6, characterized in that The polymer precursor includes polymethyl methacrylate, methyl methacrylate, functional monomers and initiators, wherein the functional monomers are used to form chemical bonds between the skin layer and the board body.

8. The method according to claim 6, characterized in that The provision of a wiring harness comprises at least one of the following: When extruding the skin layer, a geometric pattern is formed on the surface of the skin layer using an extrusion port having a preset outlet shape; After the wire harness is formed by extrusion, the surface of the wire harness is subjected to sandblasting and / or chemical etching treatment; Adding a template material for forming a porous structure into the extruded material of the skin layer, and removing the template material after the wire bundle is formed by extrusion to form a skin layer with a porous structure; An inert solvent is added to the extruded material of the skin layer, and the wire bundle is formed by extrusion, wherein the inert solvent and the polymer precursor are mutually soluble, and the refractive index of the inert solvent is close to that of the plate body.

9. The method according to claim 6, characterized in that Before curing the polymer precursor, the method further comprises: The mixture of the polymer precursor and the wire bundle is left to stand for a preset time.

10. The method according to claim 6, characterized in that The wiring harness provided comprises: The skin layer is extruded by a variable speed stretching method, so that the cross-sectional area of ​​the wire bundle changes alternately in the length direction of the wire bundle.

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