A black laser-weldable glass fiber reinforced polylactic acid plastic component and a method for manufacturing the same

Abstract

The present application relates to the technical field of high polymer material, and provides a black laser-weldable glass fiber reinforced polylactic acid plastic component and a preparation method thereof.The component comprises an upper light-transmitting material and a lower light-absorbing material; components of the upper light-transmitting material include polylactic acid, plasticizer, glass fiber, coupling agent, antioxidant, surface modifier and infrared-transmitting organic black powder; the polylactic acid of the upper light-transmitting material has a melting point of 155-170 DEG C; components of the lower light-absorbing material include polylactic acid, plasticizer, glass fiber, coupling agent, surface modifier, antioxidant and carbon black; the polylactic acid of the lower light-absorbing material has a melting point of 145-160 DEG C.The glass fiber reinforced polylactic acid plastic component prepared by the present application maintains good light transmittance and welding strength while being glass fiber reinforced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a black laser-weldable glass fiber reinforced polylactic acid plastic component and a preparation method thereof. BACKGROUND

[0002] The specific principle of laser welding is that infrared laser (800nm-1100nm) penetrates the upper light-transmitting material and reaches the surface of the lower light-absorbing material, the lower light-absorbing material is heated and melted, and the heat is transferred to the upper material, the two materials are melted on the contact surface, and the secondary polymerization is carried out under the clamping force, and the welding is completed after cooling. Therefore, the laser welding material requires that the upper material can transmit the laser to the greatest extent (>30%), the lower material needs to absorb the laser to the greatest extent, and the matching of the upper and lower materials also follows the principle of similar compatibility.

[0003] Polylactic acid is a crystalline material, but due to its extremely slow crystallization speed, it is basically in an amorphous state without crystallization treatment, thus having a high light transmittance, which provides the possibility for laser welding. However, due to the brittleness of polylactic acid itself, it cannot meet the strength requirements for laser welding in the fields of automobiles and electronic appliances, and therefore needs to be reinforced and modified. Among the methods for improving the strength of polylactic acid, the main methods include glass fiber reinforcement, mineral filling reinforcement, natural fiber reinforcement and composite filling reinforcement.

[0004] However, using mineral filling and natural fiber to reinforce and modify polylactic acid can solve the problem of insufficient strength of polylactic acid, but at the same time, it will also cause a serious decrease in light transmittance, affecting the process of laser welding.

[0005] Therefore, how to develop a polylactic acid material that is reinforced while having good light transmittance and good welding strength is an urgent technical problem to be solved by those skilled in the art. SUMMARY

[0006] In order to solve the problem of insufficient light transmittance of polylactic acid material during the process of reinforcement and modification mentioned in the background, the present application provides a black laser-weldable glass fiber reinforced polylactic acid plastic component, and the technical scheme is as follows:

[0007] The film layer structure of the black laser-weldable glass fiber reinforced polylactic acid plastic component includes an upper light-transmitting material and a lower light-absorbing material; the components of the upper light-transmitting material include polylactic acid, plasticizer, glass fiber, coupling agent, antioxidant, surface modifier and infrared-transmitting organic black powder; the melting point of the polylactic acid of the upper light-transmitting material is 155-170℃; the components of the lower light-absorbing material include polylactic acid, plasticizer, glass fiber, coupling agent, carbon black, surface modifier, antioxidant and carbon black; the melting point of the polylactic acid of the lower light-absorbing material is 145-160℃.

[0008] In an embodiment, the components of the upper layer light-transmitting material include, by weight parts, the polylactic acid 75.7-99 parts, the plasticizer 0.4-2 parts, the glass fiber 0-20 parts, the coupling agent 0-0.4 parts, the antioxidant 0.2-0.5 parts, the surface modifier 0.2-1 part, and the infrared-transmitting black organic powder 0.2-0.4 parts.

[0009] In an embodiment, the components of the lower layer light-absorbing material include, by weight parts, the polylactic acid 75.5-99 parts, the plasticizer 0.4-2 parts, the glass fiber 0-20 parts, the coupling agent 0-0.4 parts, the antioxidant 0.2-0.5 parts, the surface modifier 0.2-1 part, and the carbon black 0.2-0.6 parts.

[0010] In an embodiment, the plasticizer is one or a combination of ESO, ATBC, and TBC.

[0011] In an embodiment, the glass fiber is an alkali-free short-cut glass fiber with a diameter of 8-20 um and a length of 2-3 mm.

[0012] In an embodiment, the coupling agent is a silane coupling agent.

[0013] In an embodiment, the antioxidant is one or a combination of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester and tris[2,4-di-tert-butylphenyl]phosphite.

[0014] In an embodiment, the surface modifier is an amide lubricant and / or a stearic acid lubricant.

[0015] In an embodiment, the infrared-transmitting black organic powder is a black infrared-transmitting organic color powder and / or a black organic color powder prepared by using three primary colors.

[0016] The present application provides a preparation method of a black laser-weldable glass fiber reinforced polylactic acid plastic component as described above, which includes the following steps:

[0017] S100, according to the component formula of the upper layer light-transmitting material, the polylactic acid, the plasticizer, the coupling agent, the antioxidant, and the surface active agent are uniformly mixed in a certain proportion, and then added to a double-screw extruder from a main feeding port, the glass fiber is added to the double-screw extruder from a side feeding port, and then cooled and granulated after melt extrusion by the double-screw extruder to obtain a natural color upper layer light-transmitting material master batch;

[0018] S200, the natural color upper layer light-transmitting material master batch and the infrared-transmitting black organic powder are uniformly mixed in a certain proportion, and then single-screw injection molding is performed to obtain the upper layer light-transmitting material.

[0019] S300, according to the component formula of the lower layer light-absorbing material, the polylactic acid, the plasticizer, the coupling agent, the antioxidant, the surfactant and the carbon black are mixed uniformly in a certain proportion and then added from the main feeding port, the glass fiber is added to the double screw extruder from the side feeding port, and the black lower layer light-absorbing material master batch is obtained after the double screw extruder is melt-extruded and then cooled and granulated;

[0020] S400, the black lower layer light-absorbing material master batch is formed by single screw injection molding, and the lower layer light-absorbing material is obtained;

[0021] S500, the upper layer light-transmitting material and the lower layer light-absorbing material are laser welded under a certain clamping force, and the polylactic acid laser welding assembly is obtained after cooling;

[0022] S600, the polylactic acid laser welding assembly is annealed at a temperature of 110-130 DEG C for 3-5 min, and the black laser-weldable glass fiber reinforced polylactic acid plastic assembly is obtained.

[0023] Based on the above, compared with the prior art, the black laser-weldable glass fiber reinforced polylactic acid plastic assembly provided by the application has the following beneficial effects:

[0024] The glass fiber reinforced polylactic acid plastic assembly provided by the application maintains good light transmittance and welding strength while being glass fiber reinforced.

[0025] Other features and advantages of the application will be described in the following description, and some will become apparent from the description, or will be understood through implementation of the application. The purpose and other advantages of the application can be achieved and obtained through the structure specifically pointed out in the description and claims. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the application more clear, the technical solutions in the embodiments of the application will be described clearly and completely below, obviously, the described embodiments are some of the embodiments of the application, not all the embodiments; the technical features designed in different embodiments of the application can be combined with each other as long as they do not conflict with each other; based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0027] In the description of the present application, it should be noted that all the terms used in the present application (including technical terms and scientific terms) have the same meaning as that generally understood by the ordinary skilled person in the field to which the present application belongs, and cannot be understood as a limitation on the present application; it should be further understood that the terms used in the present application should be understood as having the same meaning as the terms in the context of the present application and the related field, and should not be understood in an idealized or overly formal sense, except as expressly defined in the present application.

[0028] The present application provides a method for preparing a black laser-weldable glass fiber reinforced polylactic acid plastic component as described above, comprising the following steps:

[0029] S100, the polylactic acid, the plasticizer, the coupling agent, the antioxidant and the surface modifier are uniformly mixed in a certain proportion, then added to a twin-screw extruder from a main feeding port, the glass fiber is added to the twin-screw extruder from a side feeding port, and the twin-screw extruder is melt-extruded and then cooled and granulated to obtain a natural color upper light-transmitting material master batch, wherein the twin-screw extrusion temperature is 155-170℃, and the screw rotation speed is 350-450rpm;

[0030] S200, the natural color upper light-transmitting material master batch and the infrared-transmitting organic black powder are uniformly mixed in a certain proportion, then single-screw injection molding is performed to obtain the upper light-transmitting material, wherein the single-screw injection molding temperature is 190-210℃;

[0031] S300, the polylactic acid, the plasticizer, the coupling agent, the antioxidant, the surfactant and the carbon black are uniformly mixed in a certain proportion, then added from a main feeding port, the glass fiber is added to a twin-screw extruder from a side feeding port, and the twin-screw extruder is melt-extruded and then cooled and granulated to obtain a black lower light-absorbing material master batch, wherein the twin-screw extrusion temperature is 145-160℃, and the screw rotation speed is 350-450rpm;

[0032] S400, the black lower light-absorbing material master batch is subjected to single-screw injection molding to obtain the lower light-absorbing material, wherein the single-screw injection molding temperature is 190-210℃;

[0033] S500, the upper light-transmitting material and the lower light-absorbing material are laser-welded under a certain clamping force, and after cooling, a polylactic acid laser-welded component is obtained;

[0034] S600, the polylactic acid laser-welded component is subjected to annealing treatment at 110-130℃ for 3-5min to obtain a black laser-weldable glass fiber reinforced polylactic acid plastic component.

[0035] The application provides the formula of the black laser-weldable glass fiber reinforced polylactic acid plastic component, wherein the film layer structure comprises an upper light-transmitting material and a lower light-absorbing material; the components of the upper light-transmitting material comprise polylactic acid, a plasticizer, glass fiber, a coupling agent, an antioxidant, a surface modifier and infrared-transmitting organic black powder; the melting point of the polylactic acid of the upper light-transmitting material is 155-170 DEG C; the components of the lower light-absorbing material comprise polylactic acid, a plasticizer, glass fiber, a coupling agent, carbon black, a surface modifier, an antioxidant and carbon black; the melting point of the polylactic acid of the lower light-absorbing material is 145-160 DEG C.

[0036] The components of the upper light-transmitting material comprise, by weight parts, 75.7-99 parts of the polylactic acid, 0.4-2 parts of the plasticizer, 0-20 parts of the glass fiber, 0-0.4 parts of the coupling agent, 0.2-0.5 parts of the antioxidant, 0.2-1 part of the surface modifier and 0.2-0.4 parts of the infrared-transmitting organic black powder.

[0037] The components of the lower light-absorbing material comprise, by weight parts, 75.5-99 parts of the polylactic acid, 0.4-2 parts of the plasticizer, 0-20 parts of the glass fiber, 0-0.4 parts of the coupling agent, 0.2-0.5 parts of the antioxidant, 0.2-1 part of the surface modifier and 0.2-0.6 parts of the carbon black.

[0038] The application further provides the examples and the comparative examples shown in the following table.

[0039] The formula (unit: weight parts) of the examples and the comparative examples provided by the application is shown in Table 1.

[0040] Table 1

[0041]

[0042]

[0043] The types of the component raw materials in the examples and the comparative examples in Table 1 are consistent, and the components are specifically as follows:

[0044] The polylactic acid selected in the upper light-transmitting material is PLA 3001D of natureworks, and the melting point is 165 DEG C; the polylactic acid selected in the lower light-absorbing material is PLA 3052D of natureworks, and the melting point is 155 DEG C.

[0045] The selected plasticizer is epoxy soybean oil ESO.

[0046] The selected glass fiber is alkali-free chopped glass fiber with a diameter of 8-20 um and a length of 2-3 mm, and the product number of the glass fiber produced by the Giant Stone Company is 568H; the selected coupling agent is a silane coupling agent, and the KH560 silane coupling agent is specifically selected; the selected nucleating agent is TMC-300 of Shanxi Chemical Research Institute; the selected antioxidant is an antioxidant composed of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester and tris[2,4-di-tert-butylphenyl] phosphite in a mass ratio of (1:1);

[0047] The selected surface modifier is a surface modifier composed of calcium stearate and amide wax in a mass ratio of (1:1); the selected infrared-transparent organic black powder is the product number H5R of the infrared-transparent organic black powder produced by the Hongkun Company; and the selected carbon black is the product number M880 of the carbon black produced by the Cabot Company.

[0048] According to the formulation in Table 1, the raw material components in the examples and the comparative examples except for Comparative Example 3 are prepared according to the following preparation method to prepare the black laser-weldable glass fiber reinforced polylactic acid plastic component, and the preparation steps are as follows:

[0049] (1) After the polylactic acid, the plasticizer, the coupling agent, the antioxidant, and the surfactant are uniformly mixed in a certain proportion, they are added to a double-screw extruder from a main feeding port, and the glass fiber is added to the double-screw extruder from a side feeding port. After melting and extrusion by the double-screw extruder, cooling and granulation are performed to obtain a natural color upper light-transmitting material master batch;

[0050] Among them, the double-screw extruder has 9 barrels, and the side feeding port is arranged in the sixth barrel (the sixth zone). During the preparation of the upper light-transmitting material, the temperature settings of the double-screw extruder from 1-9 zones are 155℃, 160℃, 170℃, 170℃, 160℃, 170℃, 160℃, 160℃, and 170℃.

[0051] (2) After the natural color upper light-transmitting material master batch and the infrared-transparent organic black powder are uniformly mixed in a certain proportion, single-screw injection molding is performed to obtain the upper light-transmitting material (this process is the infrared-transparent organic black powder external mixing injection molding); wherein the single-screw injection molding temperature is 190-210℃;

[0052] (3) After the polylactic acid, the plasticizer, the coupling agent, the antioxidant, the surfactant, and the carbon black are uniformly mixed in a certain proportion, they are added from the main feeding port, and the glass fiber is added to the double-screw extruder from the side feeding port. After melting and extrusion by the double-screw extruder, cooling and granulation are performed to obtain a black lower light-absorbing material master batch;

[0053] The double screw extruder has 9 barrels, and the side feeding port is arranged in the sixth barrel (sixth zone). In the preparation process of the lower layer light-absorbing material, the temperatures of the first to ninth zones of the double screw extruder are set to 145°C, 150°C, 160°C, 160°C, 150°C, 160°C, 150°C, 150°C, and 160°C, and the glass fibers are added from the sixth barrel.

[0054] (4) The black lower layer light-absorbing material master batch is formed by single screw injection molding, and the single screw injection molding temperature is 190-210°C, so as to obtain the lower layer light-absorbing material.

[0055] (5) The upper layer light-transmitting material and the lower layer light-absorbing material are laser welded under a certain clamping force, and after cooling, a polylactic acid laser welding assembly is obtained.

[0056] (6) The polylactic acid laser welding assembly is annealed at a temperature of 110-130°C for 3-5 min, so as to obtain a black laser-weldable glass fiber reinforced polylactic acid plastic assembly.

[0057] It should be noted that the preparation method of Comparative Example 3 is different from that of the above examples. In the above examples, the infrared-transmitting organic black powder is added by external mixing injection molding. The external mixing injection molding is that other raw material components are mixed first, then extruded and granulated by a double screw extruder, and then the infrared-transmitting organic black powder is mixed with the above natural color upper layer master batch, and then single screw injection molding is performed. In Comparative Example 3, the infrared-transmitting organic black powder is added by passing through the machine. The passing through the machine is that the infrared-transmitting organic black powder is directly mixed with other raw material components, and then extruded and granulated by a double screw extruder, and then the master batch is injection molded. That is, the difference between Comparative Example 3 and the above examples is that in step (1) of Comparative Example 3, the infrared-transmitting organic black powder is directly added to the double screw extruder, the infrared-transmitting organic black powder is extruded and cooled after being mixed with other components in the double screw extruder, and then a black upper layer light-transmitting material master batch is obtained; in step (2) of Comparative Example 3, the black upper layer light-transmitting material master batch is directly injection molded by a single screw, and the upper layer light-transmitting material is obtained.

[0058] The materials prepared in the examples and comparative examples are tested for relevant indexes, and the test results are shown in Table 2.

[0059] Table 2

[0060]

[0061]

[0062] The light transmittance test: the sample thickness is 2 mm, and the test wavelength is 1064 nm; the welding method is to use a flame-retardant sample strip with upper and lower layers, and under the action of laser and a certain clamping force, welding is carried out at a power of 16 W and a speed of 1000 mm / s, wherein the flame-retardant strip specification is 125*13*1.6 mm, the laser wavelength is 1064 nm, the clamping force is 5 bar, and the weld size is 15*5 mm; the test method for welding strength is to perform tensile test on the welded flame-retardant strip on a tensile testing machine until the sample breaks, and the maximum tensile strength force value during the entire process is taken, wherein the tensile speed is 5 mm / min.

[0063] From the test results in Table 2, it can be seen that:

[0064] In Examples 1-3, the upper light-transmitting material and the lower light-absorbing material use polylactic acid with a specific ratio and a specific melting point, and the upper light-transmitting material and the lower light-absorbing material are limited to specific raw material components in a specific ratio, and a certain amount of organic infrared-transmitting black powder is added by using the external doped injection molding method, so that the black laser-weldable polylactic acid plastic assembly prepared can maintain good light transmittance and welding strength while being glass fiber reinforced.

[0065] From the comparison results of the examples and the comparative examples, it can be seen that:

[0066] The difference between Example 1 and Comparative Example 1 is that the addition amount of the infrared-transmitting organic black powder and the carbon black in Example 1 is within the limited range of the present application, and the addition amount of the infrared-transmitting organic black powder and the carbon black in Comparative Example 1 is lower than the limited range of the present application; compared with Example 1, the welding strength in Comparative Example 1 decreases significantly, which indicates that the amount of carbon black and the amount of infrared-transmitting organic black powder cannot be too small (lower than the limited range of the present application), otherwise the light-absorbing capacity of the lower light-absorbing layer will be insufficient, and the welding strength will decrease.

[0067] The difference between Example 1 and Comparative Example 2 is that the addition amount of the infrared-transmitting organic black powder and the carbon black in Example 1 is within the limited range of the present application, and the addition amount of the infrared-transmitting organic black powder and the carbon black in Comparative Example 2 is higher than the limited range of the present application; compared with Example 1, the welding strength and the light transmittance in Comparative Example 2 decrease significantly, which indicates that the amount of carbon black and the amount of infrared-transmitting organic black powder cannot be too high (higher than the limited range of the present application), and excessive infrared-transmitting organic black powder will cause the light transmittance of the upper light-transmitting material to decrease, and the welding strength will decrease.

[0068] The difference between Example 1 and Comparative Example 3 is that the addition of the infrared-transparent organic black powder in Example 1 is by using the method of external mixing injection molding, while the addition of the infrared-transparent organic black powder in Comparative Example 3 is not by external mixing, but by mixing with other components together and then adding into the twin-screw extruder; compared with Example 1, the light transmittance and the welding strength in Comparative Example 3 are both decreased, which indicates that the addition of the infrared-transparent organic black powder by using the method of external mixing injection molding can improve the welding strength and the light transmittance.

[0069] Comparative Example 4 is based on Example 1, and a nucleating agent is added into the upper light-transmitting material, and the test results show that the welding strength and the light transmittance in Comparative Example 4 are both decreased. Since the nucleating agent has the effect of increasing the crystallinity, the loss increases when the laser passes through, and the energy required for the material to melt also increases, which leads to the decrease of the welding strength, and then it is guessed that the organic color powder is dispersed very uniformly in Comparative Example 3 when passing through the machine, which acts as a nucleating agent, leading to the increase of the crystallinity and the decrease of the welding strength, and the method of external mixing injection molding just solves this problem.

[0070] The difference between Example 1 and Comparative Example 5 is that the upper light-transmitting material and the lower light-absorbing material in Example 1 use polylactic acid with different melting points, respectively, while the upper light-transmitting material and the lower light-absorbing material in Comparative Example 5 use polylactic acid with the same melting point; compared with Comparative Example 5, the welding strength of Example 1 is improved, which indicates that when the melting point of the light-absorbing layer is lower than that of the light-transmitting layer, the welding seam can be fused better and the welding strength can also be improved.

[0071] The difference between Example 1 and Comparative Example 6 is that the addition amount of glass fiber in Example 1 is within the limited range of the present application, while the addition amount of glass fiber in Comparative Example 6 exceeds the limited range of the present application; the light transmittance in Comparative Example 6 is low and the welding appears to fall off, while the welding strength and the light transmittance in Example 1 remain good, which indicates that the excessive addition amount of glass fiber (exceeding the limited range of the present application) can easily lead to too low light transmittance and the inability to perform laser welding.

[0072] In summary, compared with the prior art, the black laser-weldable glass fiber reinforced polylactic acid plastic assembly of the present application has the upper light-transmitting material and the lower light-absorbing material by respectively selecting two polylactic acid raw material components with specific melting points and a melting point difference, and the upper light-transmitting material and the lower light-absorbing material are limited to specific raw material components in a specific ratio, and a certain amount of organic infrared-transparent black powder is added by using the method of external mixing injection molding, so that the glass fiber reinforced polylactic acid plastic assembly prepared can be glass fiber reinforced while maintaining good light transmittance and welding strength.

[0073] It needs to be particularly pointed out that the ESO described herein is epoxy soybean oil, the ATBC is acetyl tri-n-butyl citrate, and the TBC is tributyl citrate.

[0074] In addition, those skilled in the art shall understand that, although there are many problems in the prior art, each embodiment or technical solution of the present application can only be improved in one or several aspects, and it is not necessary to solve all the technical problems listed in the prior art or background art at the same time. Those skilled in the art shall understand that the content not mentioned in a claim shall not be regarded as a limitation to the claim.

[0075] In summary, the specific parameters or some commonly used reagents or raw materials in the above embodiments are specific embodiments or preferred embodiments under the concept of the present application, but not limitations thereto; those skilled in the art can make adaptive adjustment within the concept and protection scope of the present application.

[0076] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A black, laser-weldable glass fiber reinforced polylactic acid (PLA) plastic component, characterized in that: Its membrane structure includes an upper light-transmitting material and a lower light-absorbing material; By weight, the upper light-transmitting material comprises 75.7–99 parts polylactic acid, 0.4–2 parts plasticizer, 20 parts glass fiber, 0–0.4 parts coupling agent, 0.2–0.5 parts antioxidant, 0.2–1 parts surface modifier, and 0.2–0.4 parts infrared-transmitting organic black powder; the polylactic acid in the upper light-transmitting material has a melting point of 155–170°C. By weight, the components of the lower light-absorbing material include: 75.5-99 parts polylactic acid, 0.4-2 parts plasticizer, 20 parts glass fiber, 0-0.4 parts coupling agent, 0.2-0.5 parts antioxidant, 0.2-1 parts surface modifier, and 0.2-0.6 parts carbon black; the polylactic acid in the lower light-absorbing material has a melting point of 145-160°C. According to the composition formula of the upper light-transmitting material, the polylactic acid, the plasticizer, the coupling agent, the antioxidant and the surface modifier are mixed in a certain proportion and then fed into a twin-screw extruder through the main feed port. The glass fiber is fed into the twin-screw extruder through the side feed port. After being melt-extruded by the twin-screw extruder, the mixture is cooled and granulated to obtain the natural-colored upper light-transmitting material masterbatch. The original color upper layer light-transmitting material masterbatch and the infrared-transmitting organic black powder are then mixed in a certain proportion and then injection molded by a single screw to obtain the upper layer light-transmitting material.

2. The black, laser-weldable glass fiber reinforced polylactic acid (PLA) plastic component according to claim 1, characterized in that: The plasticizer is one or more of ESO, ATBC, and TBC.

3. The black, laser-weldable glass fiber reinforced polylactic acid plastic component according to claim 1, characterized in that: The glass fiber is an alkali-free short-cut glass fiber with a diameter of 8-20 μm and a length of 2-3 mm.

4. The black, laser-weldable glass fiber reinforced polylactic acid plastic component according to claim 1, characterized in that: The coupling agent is a silane coupling agent.

5. The black, laser-weldable glass fiber reinforced polylactic acid (PLA) plastic component according to claim 1, characterized in that: The antioxidant is one or more combinations of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris[2,4-di-tert-butylphenyl]phosphite.

6. The black, laser-weldable glass fiber reinforced polylactic acid (PLA) plastic component according to claim 1, characterized in that: The surface modifier is an amide-based lubricant and / or a stearic acid-based lubricant.

7. The black, laser-weldable glass fiber reinforced polylactic acid (PLA) plastic component according to claim 1, characterized in that: The infrared-transmitting organic black powder is a black infrared-transmitting organic color powder and / or a black organic color powder mixed using the three primary colors.

8. A method for preparing a black, laser-weldable glass fiber reinforced polylactic acid (PLA) plastic component as described in any one of claims 1-7, characterized in that, Includes the following steps: S100. According to the composition formula of the upper light-transmitting material, the polylactic acid, the plasticizer, the coupling agent, the antioxidant and the surface modifier are mixed in a certain proportion and then fed into a twin-screw extruder through the main feed port. The glass fiber is fed into the twin-screw extruder through the side feed port. After being melt-extruded by the twin-screw extruder, the mixture is cooled and granulated to obtain the natural-colored upper light-transmitting material masterbatch. S200: The original color upper layer light-transmitting material masterbatch and the infrared-transmitting organic black powder are mixed in a certain proportion and then injection molded by a single screw to obtain the upper layer light-transmitting material. S300. According to the composition formula of the lower light-absorbing material, the polylactic acid, the plasticizer, the coupling agent, the antioxidant, the surface modifier and the carbon black are mixed in a certain proportion and added from the main feed port. The glass fiber is added to the twin-screw extruder from the side feed port. After being melt-extruded by the twin-screw extruder, it is cooled and granulated to obtain black lower light-absorbing material masterbatch. S400, the black lower light-absorbing material masterbatch is injection molded by a single screw to obtain the lower light-absorbing material; S500: The upper light-transmitting material and the lower light-absorbing material are laser-welded under a certain clamping force, and after cooling, a polylactic acid laser-welded component is obtained. S600, the polylactic acid laser welding assembly is then annealed at a temperature of 110-130°C for 3-5 minutes to obtain a black laser-weldable glass fiber reinforced polylactic acid plastic assembly.

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