Mold for preventing deformation of thin-walled large flat plastic part

Abstract

The application belongs to the field of plastic product processing, and particularly relates to a thin-walled large-plane plastic part deformation-preventing mold and a preparation method and application thereof. The mold comprises the following steps: mixing waste recycled plastics, reinforcing fibers and a compatibilizer to obtain a premix; feeding the premix into a twin-screw extruder to melt blend and extrude, to obtain composite particles; injecting the composite particles into a mold cavity to sequentially perform high-pressure filling and pressure-keeping cooling, and obtaining a preform after demolding; and performing plasma treatment on the surface of the preform to obtain the thin-walled large-plane plastic part deformation-preventing mold. The mold is prepared from 65-75 parts of waste recycled plastics, 20-25 parts of reinforcing fibers and 5-10 parts of a compatibilizer. The thin-walled large-plane plastic part deformation-preventing mold provided by the application has good mechanical properties. Meanwhile, the two-stage injection molding process can simplify the production process on the basis of reducing the production cost, and has good application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of plastic product processing, and particularly relates to a mold for preventing deformation of a thin-walled large-plane plastic part and a preparation method and application thereof. BACKGROUND

[0002] The thin-walled large-plane plastic part refers to a plastic product with the following characteristics:

[0003] (1) Thin-walled structure: the wall thickness is relatively thin, usually between 1-2 mm.

[0004] (2) Large-area flat surface: has a large flat area, such as electronic device housings, automotive interior panels, and home appliance panels. These thin-walled large-plane plastic parts are prone to deformation due to uneven shrinkage or cooling. Therefore, in order to make the thin-walled large-plane plastic part more solid and stable, the mechanical properties of the production mold are often required to be high. However, the existing mold for thin-walled large-plane plastic parts has the following defects:

[0005] (1) High material cost: most existing molds use pure new material engineering plastics such as polyhexamethylene adipamide (PA66), polyoxymethylene (POM), or metal materials, and the raw material cost of the mold accounts for a high proportion;

[0006] (2) Complex process: traditional thin-walled large-plane plastic part molds need to be prevented from deforming during production through at least three stages of pressure retention and precise temperature control, resulting in a long process debugging period and high energy consumption;

[0007] (3) The linear expansion coefficient and warping deformation of the existing thin-walled large-plane plastic part mold are high, which cannot meet the use requirements. Therefore, a thin-walled large-plane plastic part mold with good mechanical properties, simple production process, and low cost is needed in the art. SUMMARY

[0008] In view of the above shortcomings of the prior art, the present application provides a mold for preventing deformation of a thin-walled large-plane plastic part and a preparation method and application thereof, which can solve the problems of poor mechanical properties, high production cost, and complex preparation process of the large-plane plastic part mold prepared by the prior art.

[0009] The first object of the present application is to provide a preparation method of a mold for preventing deformation of a thin-walled large-plane plastic part, comprising the following steps:

[0010] Mixing waste recycled plastics, reinforcing fibers, and compatibilizers to obtain a premix;

[0011] Melting and blending extrusion of the premix in a twin-screw extruder to obtain composite particles;

[0012] The composite particles are injected into a mold cavity to sequentially perform high-pressure filling and pressure-keeping cooling, and a preform is obtained after demolding;

[0013] The surface of the preform is subjected to plasma treatment to obtain a mold for preventing deformation of a thin-walled large-plane plastic part.

[0014] Optionally, the waste recycled plastic, the reinforcing fiber and the compatibilizer are as follows in terms of weight parts:

[0015] The waste recycled plastic is 65-75 parts

[0016] The reinforcing fiber is 20-25 parts

[0017] The compatibilizer is 5-10 parts.

[0018] The sum of the components is 100 parts.

[0019] Optionally, the waste recycled plastic includes acrylonitrile-butadiene-styrene terpolymer and / or polypropylene.

[0020] Optionally, the reinforcing fiber is carbon fiber and / or chopped glass fiber.

[0021] Optionally, the carbon fiber has a diameter of 6-9 μm and a length of 5-15 mm.

[0022] The chopped glass fiber has a diameter of 9-13 μm and a length of 3-4.5 mm.

[0023] Optionally, the compatibilizer is maleic anhydride grafted polypropylene, the weight average molecular weight of the maleic anhydride grafted polypropylene is 20,000-60,000, and the grafting rate of the maleic anhydride grafted polypropylene is 1.1-3.0 wt%.

[0024] Optionally, the extrusion temperature of the twin-screw extruder is 200-220°C, and the screw rotation speed is 250-300 rpm.

[0025] Optionally, the pressure of the high-pressure filling is 80-100 MPa, the melt temperature is 240-260°C, and the filling time is 3-5 s.

[0026] Optionally, the pressure of the pressure-keeping cooling is 35-45 MPa, the pressure-keeping time is 8-12 s, and the cooling rate is 5-8°C / min.

[0027] Optionally, the parameters for the plasma treatment of the surface of the preform include:

[0028] The treatment equipment is a normal-pressure plasma surface treatment machine equipped with a high-frequency plasma pulse generator.

[0029] The atmosphere is oxygen and / or argon.

[0030] The power is 50-200 W.

[0031] Processing time: 10-60s;

[0032] Processing temperature: 20-50℃.

[0033] A second object of the present application is to provide a thin-walled large-plane plastic part deformation-preventing mold prepared by the preparation method of the thin-walled large-plane plastic part deformation-preventing mold, which has the following mechanical properties:

[0034] Linear expansion coefficient ≤ 3 × 10⁻ 5 / ℃, test standard: JC / T 2780-2023 "Determination of humidity linear thermal expansion coefficient of wood-plastic products";

[0035] Surface hardness ≥ HRC45, test standard: Rockwell hardness test method;

[0036] Warpage deformation ≤ 0.5mm / ㎡, test standard: GB / T 1456-2021 "Bending performance test method for sandwich structure".

[0037] A further object of the present application is to provide the application of the thin-walled large-plane plastic part deformation-preventing mold in the preparation of automotive interior parts, the preparation of consumer electronic housings, the preparation of automotive interior materials, the preparation of household appliance housings, the preparation of food containers, the preparation of industrial trays, and the preparation of instrument and meter housings, wherein the automotive interior parts are instrument panel or door trim panel, and the consumer electronic housings are mobile phone backplane or notebook computer housing.

[0038] The beneficial effects of the present application are:

[0039] The present application can reduce production costs while protecting the environment by using waste recycled plastics as raw materials to prepare molds;

[0040] (2) The present application optimizes the injection molding process of the mold, and optimizes the traditional multi-stage pressure to two-stage injection pressure (high-pressure filling + medium-pressure pressure holding), which can further reduce production costs;

[0041] (3) The thin-walled large-plane plastic part deformation-preventing mold provided by the present application can ensure that the mold meets the low thickness while ensuring the mechanical properties of the mold, and has a linear expansion coefficient ≤ 3 × 10⁻ 5 / ℃, surface hardness ≥ HRC45, warpage deformation ≤ 0.5mm / ㎡, which can meet the requirements of thin-walled large-plane plastic part processing. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The preparation method flow chart of the thin-walled large-plane plastic part deformation-preventing mold provided by the present application. DETAILED DESCRIPTION

[0043] In order to make the objects, technical solutions and effects of the present application clearer and more explicit, the present application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0044] The terms "comprising", "including", "containing", "have" or "including" or any other variant thereof, as used in the herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or apparatus that comprises a list of elements is not necessarily limited to those elements, but can include other elements not explicitly listed or inherent to such composition, step, method, article or apparatus.

[0045] "Optional" or "any of" means that the matter or event described thereafter can occur or not occur, and the description includes the case where the event occurs and the case where the event does not occur.

[0046] The indefinite article "a" and "an" before an element or component of the present application does not limit the number of elements or components (i.e., the number of occurrences) to one. Thus, "a" or "an" should be interpreted to cover one or at least one, and the singular form of an element or component includes the plural unless the number clearly indicates only a singular.

[0047] The description of the terms "one embodiment", "some embodiments", "exemplarily", "specific examples" or "some examples" and the like described in the present application means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this paper, the illustrative description of the above terms is not necessarily for the same embodiment or example.

[0048] The numerical range of the present application includes not only the point values listed in the examples, but also any point values between the numerical ranges of the present application which are not listed. Due to the limitation of space and for the sake of simplicity, the present application does not exhaustively list the specific point values included in the range.

[0049] In the following examples, all reagents and consumables were purchased from conventional reagent manufacturers in the art unless otherwise specified.

[0050] The present embodiment provides a preparation method of a mold for preventing deformation of a thin-walled large-plane plastic part, comprising the following steps:

[0051] S1. mixing waste recycled plastics, reinforcing fibers and compatibilizers to obtain a premix;

[0052] S2. melting and blending extruding the premix in a twin-screw extruder to obtain composite particles;

[0053] S3. injecting the composite particles into a mold cavity to sequentially perform high-pressure filling and pressure holding and cooling, and obtaining a preform after demolding;

[0054] S4. Plasma treatment is performed on the surface of the preform to obtain a mold for preventing deformation of the thin-walled large-plane plastic part.

[0055] In some specific embodiments, the waste recycled plastic, reinforcing fiber and compatibilizer used in step S1 are as follows in terms of weight parts:

[0056] waste recycled plastic 65-75 parts

[0057] reinforcing fiber 20-25 parts

[0058] compatibilizer 5-10 parts;

[0059] wherein the total of the components is 100 parts.

[0060] In some specific embodiments, the weight parts of the waste recycled plastic are 65-75. By way of example, the weight parts of the waste recycled plastic can be 65, 66, 67, 68, 69, 70, 71, 72, 73, 74 or 75.

[0061] In some specific embodiments, the weight parts of the reinforcing fiber are 20-25. By way of example, the weight parts of the reinforcing fiber can be 20, 21, 22, 23, 24 or 25.

[0062] In some specific embodiments, the weight parts of the compatibilizer are 5-10. By way of example, the weight parts of the compatibilizer can be 5, 6, 7, 8, 9 or 10.

[0063] In some specific embodiments, the waste recycled plastic used in step S1 is recycled plastic that is a terpolymer of acrylonitrile-butadiene-styrene and / or polypropylene, that is, the waste recycled plastic can contain either or a combination of both acrylonitrile-butadiene-styrene and polypropylene, and the present embodiment does not make further limitations on the molecular weight, melt index and glass transition temperature of the polypropylene of the recycled plastic, and the use requirements are met.

[0064] In some specific embodiments, the waste recycled plastic needs to be cleaned and crushed before being mixed with the reinforcing fiber and the compatibilizer, and the present embodiment does not make additional limitations on the cleaning and crushing methods of the waste recycled plastic, and the use requirements are met in combination with the corresponding process equipment.

[0065] In some specific embodiments, the reinforcing fiber used in step S1 is carbon fiber and / or chopped glass fiber, that is, the reinforcing fiber used in the present embodiment can be carbon fiber alone, chopped fiber alone or a mixture of the two.

[0066] In some specific embodiments, the chopped glass fiber has a diameter of 9-13 μm and a length of 3-4.5 mm.

[0067] For example, the diameter of the chopped glass fiber can be 9 μm, 10 μm, 11 μm, 12 μm, or 13 μm.

[0068] For example, the length of the chopped glass fiber can be 3 mm, 3.2 mm, 3.4 mm, 3.5 mm, 3.7 mm, 3.8 mm, 4 mm, 4.1 mm, 4.2 mm, 4.4 mm, 4.5 mm, as long as the length of the end-chopped glass fiber is within the range. In the present embodiment, the chopped glass fiber with the above length and particle size is beneficial to uniform dispersion in the mixing process, and in particular, the length within the range balances the flowability and the reinforcing effect, avoiding injection filling difficulty or fiber breakage due to too long fiber.

[0069] In some specific embodiments, the carbon fiber has a diameter of 6-9 μm and a length of 5-15 mm.

[0070] For example, the diameter of the carbon fiber can be 6 μm, 7 μm, 8 μm, or 9 μm.

[0071] For example, the length of the carbon fiber can be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, or 15 mm. In the present embodiment, the carbon fiber with the above length and particle size, when used together with the chopped glass fiber, can further improve the strength of the mold.

[0072] In some specific embodiments, the compatibilizer used in step S1 is maleic anhydride grafted polypropylene, the weight average molecular weight of the maleic anhydride grafted polypropylene is 20,000-60,000, and the grafting rate of the maleic anhydride grafted polypropylene is 1.1-3.0 wt%. For example, the weight average molecular weight of the maleic anhydride grafted polypropylene can be 20,000, 25,000, 30,000, 35,000, 40,000, 45,000, 50,000, 55,000, or 60,000, as long as the weight average molecular weight of the maleic anhydride grafted polypropylene is within the range. In the present embodiment, the maleic anhydride group in the maleic anhydride grafted polypropylene is polar and can combine with the hydroxyl or amino group on the surface of the carbon fiber and the chopped glass fiber. Meanwhile, the polypropylene segment group in the maleic anhydride grafted polypropylene is non-polar and can be compatible with the waste plastic matrix (such as acrylonitrile-butadiene-styrene terpolymer and polypropylene), forming a stable interface structure of “fiber-compatibilizer-matrix”. This can effectively improve the interface compatibility and on this basis, improve the bonding force between the fiber and the matrix, so that the external load can be more effectively transmitted to the fiber, improving the rigidity and anti-deformation ability of the mold.

[0073] In some specific embodiments, the extrusion temperature for extruding the premix using the twin-screw extruder in step S2 is 200-220℃, and the screw rotation speed is 250-300rpm.

[0074] For example, the extrusion temperature can be 200℃, 205℃, 210℃, 215℃, 220℃, as long as the extrusion temperature is within this range.

[0075] For example, the screw rotation speed can be 250rpm, 260rpm, 270rpm, 280rpm, 290rpm, 300rpm, as long as the screw rotation speed is within this range.

[0076] In some specific embodiments, the composite particles are injection molded in step S3 using a high-pressure filling + pressure holding cooling method. Specifically, the pressure for high-pressure filling is 80-100MPa, the melt temperature is 240-260℃, and the filling time is 3-5s.

[0077] For example, the pressure for high-pressure filling can be 80MPa, 85MPa, 90MPa, 95MPa, 100MPa, as long as the pressure for high-pressure filling is within this range.

[0078] For example, the melt temperature for high-pressure filling can be 240℃, 245℃, 250℃, 255℃, 260℃, as long as the melt temperature for high-pressure filling is within this range.

[0079] In some specific embodiments, the pressure for pressure holding cooling is 35-45MPa, the pressure holding time is 8-12s, and the cooling rate is 5-8℃ / min.

[0080] For example, the pressure for pressure holding cooling can be 35MPa, 37MPa, 39MPa, 40MPa, 41MPa, 43MPa, 45MPa, as long as the pressure for pressure holding cooling is within this range.

[0081] For example, the cooling rate during the pressure holding stage can be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, as long as the cooling rate during the pressure holding stage is within this range.

[0082] In this embodiment, the injection molding method of high-pressure filling + pressure holding cooling is used to replace the traditional injection molding process with more stages, which can optimize the process flow and further reduce the production cost.

[0083] In some specific embodiments, step S4 requires plasma treatment on the surface of the injection-molded preform. Specifically, the preform surface is treated by a normal-pressure plasma surface treatment machine equipped with a high-frequency plasma pulse generator. The plasma treatment parameters are as follows:

[0084] Atmosphere: oxygen and / or argon;

[0085] Power: 50-200 W;

[0086] Treatment time: 10-60 s;

[0087] Treatment temperature: 20-50℃.

[0088] For example, the power of the plasma surface treatment machine can be 50 W, 75 W, 100 W, 125 W, 150 W, 175 W, 200 W, as long as the treatment power of the plasma from the surface treatment machine is within this range.

[0089] For example, the treatment time of the plasma surface treatment can be 10 s, 20 s, 30 s, 40 s, 50 s, 60 s, as long as the treatment time of the plasma is within this range.

[0090] For example, the temperature of the plasma treatment can be 20℃, 30℃, 40℃, 50℃, as long as the temperature of the plasma treatment is within this range.

[0091] In this embodiment, by treating the surface of the preform with low-temperature plasma, the mold can be protected while avoiding thermal deformation of the mold or thermal aging of the material caused by high temperature, and the mold can be better protected.

[0092] The second embodiment of the present application provides a mold for preventing deformation of a thin-walled large-plane plastic part, which is prepared by the preparation method of the mold for preventing deformation of a thin-walled large-plane plastic part. The mechanical properties of the mold are as follows:

[0093] Linear expansion coefficient ≤ 3 × 10⁻ 5 / ℃, test standard: JC / T 2780-2023 "Determination of humidity linear thermal expansion coefficient of wood-plastic products";

[0094] Surface hardness ≥ HRC45, test standard: Rockwell hardness test method;

[0095] Warpage deformation ≤ 0.5 mm / ㎡, test standard: GB / T 1456-2021 "Bending performance test method for sandwich structure".

[0096] The second embodiment of the present application provides the application of the deformation-preventing mold for thin-walled large-plane plastic parts in the preparation of automobile interior parts, the preparation of consumer electronic housings, the preparation of automobile interior materials, the preparation of household appliance housings, the preparation of food containers, the preparation of industrial trays, and the preparation of instrument and meter housings, wherein the automobile interior parts are instrument panel or door trim panel, and the consumer electronic housings are mobile phone back plate or notebook computer housing.

[0097] The technical solutions of the present application are further explained and described below in combination with specific embodiments.

[0098] Further description

[0099] (1) Test standard:

[0100] Linear thermal expansion coefficient: 780-2023 "Determination of the linear thermal expansion coefficient of wood-plastic products in humidity";

[0101] Surface hardness: Rockwell hardness test method;

[0102] Warping deformation: "Laminate structure bending performance test method".

[0103] (2) Acrylonitrile-butadiene-styrene is abbreviated as ABS.

[0104] Example 1

[0105] 1. Raw materials and proportioning of the deformation-preventing mold for thin-walled large-plane plastic parts

[0106]

[0107] 2. Process parameters

[0108] (1) Melt blending:

[0109] Double-screw extruder temperature: 210℃.

[0110] Screw rotation speed: 280 rpm.

[0111] (2) Injection molding:

[0112] First stage (high-pressure filling): pressure 90 MPa, melt temperature 250℃, filling time 4 s.

[0113] Second stage (pressure maintaining and cooling): pressure 40 MPa, pressure maintaining time 10 s, cooling rate 6℃ / min.

[0114] (3) Plasma treatment:

[0115] Power: 120 W, treatment time 30 s, temperature 30℃, argon atmosphere.

[0116] 3. Performance test results

[0117]

[0118] Example 2

[0119] 1. Raw material and proportioning of mold for preventing deformation of thin-walled large-plane plastic part

[0120]

[0121] 2. Process parameters

[0122] (1) Melt blending:

[0123] Temperature of twin-screw extruder: 220°C.

[0124] Screw rotation speed: 300 rpm.

[0125] (2) Injection molding:

[0126] First stage (high-pressure filling): pressure 100 MPa, melt temperature 260°C, filling time 3 s.

[0127] Second stage (pressure maintaining and cooling): pressure 45 MPa, pressure maintaining time 8 s, cooling rate 8°C / min.

[0128] (3) Plasma treatment:

[0129] Power: 200 W, treatment time 15 s, temperature 50°C, oxygen atmosphere.

[0130] 3. Performance test results

[0131]

[0132] Example 3

[0133] 1. Raw material and proportioning of mold for preventing deformation of thin-walled large-plane plastic part

[0134]

[0135] 2. Process parameters

[0136] (1) Melt blending:

[0137] Temperature of twin-screw extruder: 200°C.

[0138] Screw rotation speed: 250 rpm.

[0139] Injection molding:

[0140] (2) First stage (high pressure filling): pressure 85 MPa, melt temperature 240°C, filling time 5 s.

[0141] Second stage (pressure holding and cooling): pressure 35 MPa, pressure holding time 12 s, cooling rate 5°C / min

[0142] (3) Plasma treatment:

[0143] Power: 80 W, treatment time 60 s, temperature 25°C, argon + oxygen mixed atmosphere.

[0144] 3. Performance test results

[0145]

[0146] Comparative example

[0147] The difference between this comparative example and Example 1 is only in the weight average molecular weight of the maleic anhydride grafted polypropylene used, which is as follows:

[0148] 1. Raw materials and proportions of the mold for preventing deformation of thin-walled large planar plastic parts

[0149]

[0150] 2. Process parameters

[0151] (1) Melt blending:

[0152] Temperature of twin-screw extruder: 210°C.

[0153] Screw rotation speed: 280 rpm.

[0154] (2) Injection molding:

[0155] First stage (high pressure filling): pressure 90 MPa, melt temperature 250°C, filling time 4 s

[0156] Second stage (pressure holding and cooling): pressure 40 MPa, pressure holding time 10 s, cooling rate 6°C / min

[0157] (3) Plasma treatment:

[0158] Power: 120 W, treatment time 30 s, temperature 30°C, argon atmosphere.

[0159] 3. Performance test results

[0160]

[0161] From the performance test data of Example 1 and Comparative Example 3, it can be seen that the maleic anhydride grafted polypropylene used as a compatibilizer in the comparative example has a lower weight average molecular weight and grafting rate than that of Example 1, and the linear expansion coefficient is increased by 68% and the Rockwell hardness is reduced by 8. It can be seen that the mold for preventing deformation of the thin-walled large-plane plastic part provided by the present application has more excellent mechanical properties, and can better prevent the deformation of the thin-walled large-plane plastic part during preparation.

[0162] It should be understood that the application of the present application is not limited to the above examples, and those skilled in the art can make improvements or changes according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the present application.

Claims

1. A method for preparing a mold to prevent deformation of thin-walled, large-planar plastic parts, characterized in that, The method comprises the following steps: mixing waste recycled plastics, reinforcing fibers and compatibilizers to obtain a premix; melting and blending the premix in a double-screw extruder to obtain composite particles; injecting the composite particles into a mold cavity to sequentially perform high-pressure filling and pressure-keeping cooling, and obtaining a preform after demolding; performing plasma treatment on the surface of the preform to obtain a mold for preventing deformation of a thin-walled large-planar plastic part; the waste recycled plastics, the reinforcing fibers and the compatibilizers are as follows in terms of weight parts: waste recycled plastics: 65-75 parts reinforcing fibers: 20-25 parts compatibilizers: 5-10 parts; wherein the total of the components is 100 parts; the waste recycled plastics comprise acrylonitrile-butadiene-styrene terpolymer and / or polypropylene; the reinforcing fibers are carbon fibers and / or chopped glass fibers; the carbon fibers have a diameter of 6-9 μm and a length of 5-15 mm; the chopped glass fibers have a diameter of 9-13 μm and a length of 3-4.5 mm; the compatibilizers are maleic anhydride grafted polypropylene, the maleic anhydride grafted polypropylene has a weight average molecular weight of 20,000-60,000, and the maleic anhydride grafted polypropylene has a grafting rate of 1.1-3.0 wt%.

2. The method for preparing a mold for preventing deformation of thin-walled, large-planar plastic parts according to claim 1, characterized in that, the extrusion temperature of the double-screw extruder is 200-220°C, and the screw rotation speed is 250-300 rpm.

3. The method for preparing a mold for preventing deformation of thin-walled, large-planar plastic parts according to claim 1, characterized in that, the pressure of the high-pressure filling is 80-100 MPa, the melt temperature is 240-260°C, and the filling time is 3-5 s; the pressure of the pressure-keeping cooling is 35-45 MPa, the pressure-keeping time is 8-12 s, and the cooling rate is 5-8°C / min.

4. The method for preparing a mold for preventing deformation of thin-walled, large-planar plastic parts according to claim 1, characterized in that, the parameters for the plasma treatment on the surface of the preform include: treatment equipment: atmospheric plasma surface treatment machine equipped with a high-frequency plasma pulse generator; atmosphere: oxygen and / or argon; power: 50-200 W; treatment time: 10-60 s; treatment temperature: 20-50°C.

5. A mold for preventing deformation of a thin-walled large planar plastic part, characterized by, obtained by the method for preparing a mold for preventing deformation of a thin-walled large-planar plastic part according to any one of claims 1-4, wherein: The mold for preventing deformation of the thin-walled large-plane plastic part has a linear expansion coefficient ≤3×10 -5 / ℃, and the test standard is JC / T2780-2023 "Determination of humidity linear thermal expansion coefficient of wood-plastic products"; the surface hardness of the mold for preventing deformation of a thin-walled large-planar plastic part is ≥HRC45, and the test standard is Rockwell hardness test method; the warping deformation amount of the mold for preventing deformation of a thin-walled large-planar plastic part is ≤0.5 mm / ㎡, and the test standard is GB / T1456-2021 "sandwich structure bending performance test method".

6. Use of the mold for preventing deformation of a thin-walled large planar plastic part according to claim 5 in the manufacture of an automotive interior part, in the manufacture of a consumer electronics housing, in the manufacture of an automotive interior material, in the manufacture of a household appliance housing, in the manufacture of a food container, in the manufacture of an industrial tray, in the manufacture of an instrument housing, characterized in that, the automotive interior part is an instrument panel or a door trim panel, and the consumer electronics housing is a mobile phone back plate or a notebook computer housing.

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