Paper fiber aluminum cover plate for circuit board drilling and preparation method of paper fiber aluminum cover plate

Abstract

The invention relates to a paper fiber aluminum cover plate for circuit board drilling and a preparation method thereof, and belongs to the technical field of composite materials. The aluminum cover plate is composed of an aluminum sheet and a paper fiber composite layer, and the paper fiber composite layer comprises, by weight, 38-46% of paper fibers, 3.5-4.5% of a compatibilizing lubricant, 4.5-7% of a tackifier, 0.12-0.15% of an antioxidant and the balance polylactic resin. The compatibilization lubricant is substituted by double-terminal hydroxyl silicone oil and methyl vinyl dichlorosilane, then p-fluorobenzoyl chloride and terminal residual hydroxyl react for blocking, a terminal fluorobenzene structure is introduced for modification, gamma-mercaptopropyltriethoxysilane and a vinyl structure on a side chain of an intermediate are subjected to addition, and a side chain ethoxysilane structure is introduced for modification; the compatibilization lubricant reduces the friction between polylactic acid and paper fibers and the friction between polylactic acid macromolecules close to the surface layer of the paper fibers, improves the drilling precision and reduces the drilling needle breaking rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and in particular relates to a paper fiber aluminum cover plate for drilling circuit boards and a preparation method thereof. Background Art

[0002] Back drilling of circuit boards is a technology that optimizes signal transmission by removing unused copper pillars in through-holes. The main function of the cover plate is to protect the surface of the circuit board and prevent scratches on the surface of the circuit board. At the same time, it suppresses the outlet flash on the surface of the circuit board and improves drilling accuracy.

[0003] Traditional circuit board covers are made of aluminum sheets, which have good thermal conductivity, can help dissipate heat, reduce the heat accumulation caused by friction during the drilling process, and are relatively low in cost. However, the surface of the aluminum sheet is smooth and easy to slip during drilling, resulting in poor positioning effect and low hole position accuracy. Therefore, various composite cover plates have been derived in the prior art, such as resin composite cover plates, including phenolic resin composite cover plates and epoxy resin composite cover plates. Such composite cover plates can effectively solve the problem of aluminum sheet slipping during drilling. However, the waste material after drilling is difficult to be processed, which is easy to cause environmental pollution and is gradually being eliminated by the market. At present, the use of resin for coating and impregnation of degradable paper is widely used. The method of packaging and then bonding with aluminum sheets to form the paper reduces the amount of resin used to a certain extent and alleviates environmental pressure. However, the composite resin material is still difficult to handle, resulting in complicated post-processing of the paper material. In addition, the drill needle must pass through at least the resin layer, paper layer, adhesive layer and aluminum sheet layer during drilling. The friction between the layers is different, which can easily cause uneven force on the drill needle, and then the drill needle offset, making it difficult to improve drilling accuracy. Polylactic acid is a degradable material. It has excellent application prospects when combined with existing paper fiber as a cover plate. However, in actual applications, it is found that polylactic acid has a large friction coefficient. Especially after being compounded with paper fiber, it is easy to cause thread entanglement, which affects drilling accuracy. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide a paper fiber aluminum cover plate for circuit board drilling and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A paper fiber aluminum cover plate for drilling circuit boards is composed of an aluminum sheet and a paper fiber composite layer. The paper fiber composite layer comprises, by weight percentage, 38-46 wt% of paper fiber, 3.5-4.5 wt% of a compatibilizer lubricant, 4.5-7 wt% of a tackifier, and 0.12-0.15 wt% of an antioxidant, with the remainder being polylactic acid resin.

[0007] Preferably, the tackifier is a terpene resin with a softening temperature not higher than 120° C., which can be effectively dispersed and thickened in the melt, thereby improving the bonding properties of the paper fiber composite layer.

[0008] A method for preparing a paper fiber aluminum cover plate for drilling a circuit board comprises the following steps:

[0009] Step S1: mixing polylactic acid resin, paper fiber, compatibilizer lubricant, tackifier and antioxidant, melt-kneading and crushing the mixture to obtain a composite masterbatch;

[0010] Step S2: plasticize and extrude the composite masterbatch, scrape the plasticized melt onto the surface of the preheated aluminum sheet, and then roll it to determine the thickness and cool it to form a paper fiber composite layer on the surface of the aluminum sheet. After cutting and deburring, it is made into a paper fiber aluminum cover plate.

[0011] Furthermore, the discharge temperature of the plasticized melt of the composite masterbatch is 195±5°C, and the mold temperature for rolling and thickness determination is 120-140°C. Under this temperature control, the molding accuracy of the paper fiber composite layer is stable.

[0012] Furthermore, the thickness of the paper fiber composite layer is 0.9-1.6 times that of the aluminum sheet.

[0013] The compatibilized lubricant is prepared by the following method:

[0014] Step A1: Mix dihydroxyl silicone oil, triethylamine, and anhydrous dioxane, introduce dry gas protection, control the temperature of the water bath at 20-35°C, apply stirring at 120-180 rpm, slowly add methylvinyldichlorosilane, and react for 1.5-2.2 hours, then add p-fluorobenzoyl chloride, mix, heat to 70-90°C, and react for 1-1.5 hours. After the reaction, remove the dioxane by vacuum rotary evaporation, wash the substrate with water, and dry it to obtain an intermediate;

[0015] Furthermore, the hydroxyl content of the bihydroxy-terminated silicone oil, methylvinyldichlorosilane, p-fluorobenzoyl chloride, triethylamine and anhydrous dioxane are charged in a ratio of 0.1 mmol: 30-40 mmol: 25-50 mmol: 15-25 mL: 180-260 mL. The bihydroxy-terminated silicone oil reacts with methylvinyldichlorosilane to form an organosilicon oligomer containing a vinyl block, which is then capped by reacting p-fluorobenzoyl chloride with the residual terminal hydroxyl group to introduce a terminal fluorobenzene structure modification.

[0016] Furthermore, the average molecular weight of the double-terminal hydroxy silicone oil is not higher than 2000, has good reactivity, and forms block oligomers dispersed in the polylactic acid matrix.

[0017] Step A2: Mix the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile and anhydrous toluene, heat to 60-70°C, and stir at 90-120 rpm for 30-50 minutes. Then stop heating and apply 150-200 W / m 2The reaction was continued under ultraviolet irradiation for 3-4 hours. After the reaction was completed, the toluene was removed by vacuum rotary evaporation to obtain a compatibilized lubricant;

[0018] Furthermore, the feed ratio of the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile and anhydrous toluene is 50g:10-18mmol:20-30mg:100-150mL, azobisisobutyronitrile decomposes to form free radical-activated double bonds and thiol groups, and then under the induction of ultraviolet irradiation, the activated double bonds and thiol groups add to introduce ethoxysilane structural modification into the side chain of the intermediate molecule.

[0019] Beneficial effects of the present invention:

[0020] The aluminum cover plate of the present invention uses a traditional aluminum sheet as the base and a composite material of polylactic acid and paper fiber as the surface layer, which reduces the amount of aluminum used. In addition, polylactic acid and paper fiber are both biodegradable materials. Compared with existing coated cover plates, laminated paper composite cover plates, etc., drilling waste is easy to post-process and has less pollution to the environment.

[0021] The invention discloses a compatibilizing lubricant suitable for a composite material of polylactic acid and paper fiber. The compatibilizing lubricant is formed by replacing a double-terminal hydroxyl silicone oil with methylvinyldichlorosilane to form an organosilicon oligomer containing a vinyl block, and then capped by reacting p-fluorobenzoyl chloride with a terminal residual hydroxyl group, and modified by introducing a terminal fluorobenzene structure to prepare an intermediate, and then adding γ-mercaptopropyltriethoxysilane to the vinyl structure on the side chain of the intermediate to introduce a side chain ethoxysilane structure modification; in the melt-mixing process, the compatibilizing lubricant is coupled with the paper fiber, and a macromolecular organosilicon chain is introduced into the surface layer of the paper fiber to reduce the friction between the paper fiber and the polylactic acid. The terminal fluorobenzene structure It is dispersed between the bonding layer of paper fiber and polylactic acid, reducing the friction between the polylactic acid macromolecular chains in the bonding layer, thereby fully lubricating the paper fiber and polylactic acid. On the one hand, it can increase the proportion of paper fiber in the composite layer, give full play to the reinforcing effect of the paper fiber, make the composite layer less likely to deform during the drilling process, and reduce the drill bit deviation caused by the composite layer. On the other hand, the drill bit can fully slide when in contact with the paper fiber, reducing the drill bit deviation caused by the paper fiber entanglement, thereby making the drilling accuracy higher. In addition, thanks to the lubrication and anti-entanglement improvement of the extended lubricant, the drilling resistance of the drill bit is effectively reduced, the drill bit wear is relatively low, and the needle breakage failure rate is reduced. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] Example 1: Preparation of a paper fiber aluminum cover plate, specifically as follows:

[0024] (1) Preparation of extended lubricant

[0025] Step A1: Take bihydroxyl silicone oil, triethylamine and anhydrous dioxane, mix them, pass dry nitrogen protection, control the temperature of the water bath at 20°C, apply stirring at 120 rpm, slowly add methylvinyldichlorosilane and react for 2.2 hours, then add p-fluorobenzoyl chloride and mix, raise the temperature to 70°C and react for 1.5 hours, wherein the bihydroxyl silicone oil is selected from IOTA 2110 type raw material with a molecular weight of 1000, and the hydroxyl content of the bihydroxyl silicone oil, methylvinyldichlorosilane, p-fluorobenzoyl chloride, triethylamine and anhydrous dioxane are 0.1 mmol: 40 mmol: 25 mmol: 15 mL: 180 mL. After the reaction, the dioxane is removed by reduced pressure rotary evaporation, and the substrate is washed with water and dried to obtain an intermediate.

[0026] Step A2: Mix the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile and anhydrous toluene, heat to 60°C, and stir at 90 rpm for 50 minutes. Then stop heating and apply 150W / m 2 The reaction was continued under ultraviolet irradiation for 4 hours, wherein the feed ratio of the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile and anhydrous toluene was 50 g:10 mmol:20 mg:100 mL. After the reaction was completed, the toluene was removed by vacuum rotary evaporation to obtain a compatibilized lubricant.

[0027] (2) Preparation of paper fiber aluminum cover

[0028] According to the weight percentage, the raw materials are 38wt% of paper fiber, which is commercially available wood pulp paper fiber; 3.5wt% of the compatibilizing lubricant, which is homemade in this embodiment; 7wt% of the tackifier, which is selected from M105 type terpene resin has a softening temperature of 105°C; 0.12wt% of antioxidant is selected from antioxidant 1010 and antioxidant 168 compounded in equal weight ratio; the balance is polylactic acid resin, and JSC-710H type resin raw material is selected.

[0029] Step S1: polylactic acid resin, paper fiber, compatibilizer lubricant, tackifier and antioxidant are mixed and added, melt-kneaded at 180° C. until the torque is stable, and the discharged material is cooled and crushed to obtain a composite masterbatch.

[0030] Step S2: plasticize and extrude the composite masterbatch using a twin-screw extruder, control the discharge temperature of the plasticized melt to 195±5°C, preheat the aluminum sheet to 220±10°C, scrape the plasticized melt onto the surface of the preheated aluminum sheet, and then roll to a fixed thickness. The mold temperature of the rolling mold is 140°C. After cooling and forming, a paper fiber composite layer is formed on the surface of the aluminum sheet, which is then cut and deburred to produce a paper fiber aluminum cover.

[0031] Example 2: Preparation of a paper fiber aluminum cover plate, specifically as follows:

[0032] (1) Preparation of extended lubricant

[0033] Step A1: Take bihydroxyl silicone oil, triethylamine and anhydrous dioxane, mix them, introduce dry nitrogen protection, control the temperature of the water bath at 35°C, apply stirring at 180 rpm, slowly add methylvinyldichlorosilane and react for 1.5 hours, then add p-fluorobenzoyl chloride and mix, heat to 90°C and react for 1 hour, wherein the bihydroxyl silicone oil is selected from IOTA 2110 type raw material with a molecular weight of 2000, and the hydroxyl content of the bihydroxyl silicone oil, methylvinyldichlorosilane, p-fluorobenzoyl chloride, triethylamine and anhydrous dioxane are fed in a ratio of 0.1 mmol: 30 mmol: 50 mmol: 25 mL: 260 mL. After the reaction, the dioxane is removed by vacuum rotary evaporation, and the substrate is washed with water and dried to obtain an intermediate.

[0034] Step A2: Mix the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile and anhydrous toluene, heat to 70°C, and stir at 120 rpm for 30 minutes. Then stop heating and apply 200 W / m 2 The reaction was continued under ultraviolet irradiation for 3 h, wherein the feed ratio of the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile and anhydrous toluene was 50 g:18 mmol:30 mg:150 mL. After the reaction was completed, the toluene was removed by vacuum rotary evaporation to obtain a compatibilized lubricant.

[0035] (2) Preparation of paper fiber aluminum cover

[0036] According to the weight percentage, the raw materials are 46wt% of paper fiber, which is commercially available wood pulp paper fiber; 4.5wt% of the compatibilizing lubricant, which is homemade in this embodiment; and 4.5wt% of the tackifier, which is selected from M105 type terpene resin has a softening temperature of 105°C; 0.15wt% antioxidant is selected from antioxidant 1010 and antioxidant 168 compounded in equal weight ratio; the balance is polylactic acid resin, and JSC-710H type resin raw material is selected.

[0037] Step S1: polylactic acid resin, paper fiber, compatibilizer lubricant, tackifier and antioxidant are mixed and added, melt-kneaded at 180° C. until the torque is stable, and the discharged material is cooled and crushed to obtain a composite masterbatch.

[0038] Step S2: plasticize and extrude the composite masterbatch using a twin-screw extruder, control the discharge temperature of the plasticized melt to 195±5°C, preheat the aluminum sheet to 220±10°C, scrape the plasticized melt onto the surface of the preheated aluminum sheet, and then roll to a fixed thickness. The mold temperature of the rolling mold is 120°C. After cooling and forming, a paper fiber composite layer is formed on the surface of the aluminum sheet, which is then cut and deburred to form a paper fiber aluminum cover.

[0039] Example 3: Preparation of a paper fiber aluminum cover plate, specifically as follows:

[0040] (1) Preparation of extended lubricant

[0041] Step A1: Take bihydroxyl silicone oil, triethylamine and anhydrous dioxane, mix them, introduce dry nitrogen protection, control the temperature of the water bath at 25°C, apply stirring at 120 rpm, slowly add methylvinyldichlorosilane and react for 2 hours, then add p-fluorobenzoyl chloride and mix, heat to 90°C and react for 1.2 hours, wherein the bihydroxyl silicone oil is selected from IOTA 2110 type raw material with a molecular weight of 1000, and the hydroxyl content of the bihydroxyl silicone oil, methylvinyldichlorosilane, p-fluorobenzoyl chloride, triethylamine and anhydrous dioxane are 0.1 mmol: 35 mmol: 30 mmol: 20 mL: 200 mL. After the reaction, the dioxane is removed by reduced pressure rotary evaporation, and the substrate is washed with water and dried to obtain an intermediate.

[0042] Step A2: Mix the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile and anhydrous toluene, heat to 60°C, and stir at 120 rpm for 50 minutes. Then stop heating and apply 150W / m 2 The reaction was continued under ultraviolet irradiation for 3.2 h, wherein the feed ratio of the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile and anhydrous toluene was 50 g:12 mmol:20 mg:120 mL. After the reaction was completed, the toluene was removed by vacuum rotary evaporation to obtain a compatibilized lubricant.

[0043] (2) Preparation of paper fiber aluminum cover

[0044] According to the weight percentage, the raw materials are 40wt% of paper fiber, which is commercially available wood pulp paper fiber; 3.8wt% of the compatibilizing lubricant, which is homemade in this embodiment; 5.8wt% of the tackifier, which is selected from M105 type terpene resin has a softening temperature of 105°C; 0.15wt% antioxidant is selected from antioxidant 1010 and antioxidant 168 compounded in equal weight ratio; the balance is polylactic acid resin, and JSC-710H type resin raw material is selected.

[0045] Step S1: polylactic acid resin, paper fiber, compatibilizer lubricant, tackifier and antioxidant are mixed and added, melt-kneaded at 180° C. until the torque is stable, and the discharged material is cooled and crushed to obtain a composite masterbatch.

[0046] Step S2: plasticize and extrude the composite masterbatch using a twin-screw extruder, control the discharge temperature of the plasticized melt to 195±5°C, preheat the aluminum sheet to 220±10°C, scrape the plasticized melt onto the surface of the preheated aluminum sheet, and then roll to a fixed thickness. The mold temperature of the rolling mold is 130°C. After cooling and forming, a paper fiber composite layer is formed on the surface of the aluminum sheet, which is then cut and deburred to form a paper fiber aluminum cover.

[0047] Example 4: Preparation of a paper fiber aluminum cover plate, specifically as follows:

[0048] (1) Preparation of extended lubricant

[0049] Step A1: Take bihydroxyl silicone oil, triethylamine and anhydrous dioxane, mix them, pass dry nitrogen protection, control the temperature of the water bath at 30°C, apply stirring at 180 rpm, slowly add methylvinyldichlorosilane and react for 1.8 hours, then add p-fluorobenzoyl chloride and mix, heat to 80°C and react for 1.5 hours, wherein the bihydroxyl silicone oil is selected from IOTA 2110 type raw material with a molecular weight of 2000, and the hydroxyl content of the bihydroxyl silicone oil, methylvinyldichlorosilane, p-fluorobenzoyl chloride, triethylamine and anhydrous dioxane are 0.1mmol:35mmol:30mmol:20mL:240mL. After the reaction, the dioxane is removed by reduced pressure rotary evaporation, and the substrate is washed with water and dried to obtain an intermediate.

[0050] Step A2: Mix the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile and anhydrous toluene, heat to 70°C, and stir at 120 rpm for 50 minutes. Then stop heating and apply 150W / m 2 The reaction was continued under ultraviolet irradiation for 3.5 h, wherein the feed ratio of the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile and anhydrous toluene was 50 g:16 mmol:25 mg:130 mL. After the reaction was completed, the toluene was removed by vacuum rotary evaporation to obtain a compatibilized lubricant.

[0051] (2) Preparation of paper fiber aluminum cover

[0052] According to the weight percentage, the raw materials are 43wt% of paper fiber, which is commercially available wood pulp paper fiber; 4wt% of the compatibilizing lubricant, which is homemade in this embodiment; and 6.2wt% of the tackifier, which is selected from M105 type terpene resin has a softening temperature of 105°C; 0.13wt% of antioxidant is selected from antioxidant 1010 and antioxidant 168 compounded in equal weight ratio; the balance is polylactic acid resin, and JSC-710H type resin raw material is selected.

[0053] Step S1: polylactic acid resin, paper fiber, compatibilizer lubricant, tackifier and antioxidant are mixed and added, melt-kneaded at 180° C. until the torque is stable, and the discharged material is cooled and crushed to obtain a composite masterbatch.

[0054] Step S2: plasticize and extrude the composite masterbatch using a twin-screw extruder, control the discharge temperature of the plasticized melt to 195±5°C, preheat the aluminum sheet to 220±10°C, scrape the plasticized melt onto the surface of the preheated aluminum sheet, and then roll to a fixed thickness. The mold temperature of the rolling mold is 130°C. After cooling and forming, a paper fiber composite layer is formed on the surface of the aluminum sheet, which is then cut and deburred to form a paper fiber aluminum cover.

[0055] Comparative Example 1: This comparative example refers to Example 4, except that paper fiber and compatibilizing lubricant are not added, and the polylactic acid resin is supplemented to 100 wt %. The rest of the implementation process is exactly the same.

[0056] Comparative Example 2: This comparative example refers to Example 4, except that the compatibilized lubricant is replaced with 1 wt% of silane coupling agent KH-570, 2 wt% of PL-218 silicone powder, and 1 wt% of TPW604 lubricant. The rest of the implementation process is exactly the same.

[0057] Samples were taken from the aluminum cover plate prepared as above, and the thickness of the aluminum sheet (H0) and the thickness of the composite layer (H1) were tested, as shown in Table 1:

[0058] Table 1 Specification test results of the aluminum cover plate of the present invention

[0059]

[0060]

[0061] The aluminum cover plate and 0.2 mm aluminum sheet prepared as above were used as comparative example 3 to perform drilling tests on the PCB board. The hole diameters were 0.1 mm, 0.15 mm, and 0.2 mm, respectively. The specific test data are shown in Tables 2 to 4.

[0062] Table 20.1mm drilling test results

[0063] Average error / mil Maximum error / mil CPK value Drill break rate Example 1 0.710 1.516 3.154 0 / 5 Example 2 0.609 1.227 3.307 0 / 5 Example 3 0.675 1.309 3.624 0 / 5 Example 4 0.642 1.103 3.905 0 / 5 Comparative Example 1 0.690 1.140 3.288 2 / 5 Comparative Example 2 0.783 1.963 2.891 0 / 5 Comparative Example 3 0.857 1.822 2.554 1 / 5

[0064] Table 30.15mm drilling test results

[0065] Average error / mil Maximum error / mil CPK value Drill break rate Example 1 0.657 1.825 2.580 0 / 5 Example 2 0.560 1.603 2.873 0 / 5 Example 3 0.592 1.667 3.329 0 / 5 Example 4 0.619 1.413 3.455 0 / 5 Comparative Example 1 0.705 1.607 3.014 2 / 5 Comparative Example 2 0.769 2.217 2.133 0 / 5 Comparative Example 3 0.904 1.945 2.271 0 / 5

[0066] Table 4 0.2mm drilling test results

[0067]

[0068]

[0069] It can be seen from the test results in Tables 2 to 4 that the paper fiber aluminum cover plate prepared in the embodiment is applied to drilling holes in circuit boards, with high drilling accuracy and low drill breakage rate.

[0070] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0071] The above descriptions are merely examples and illustrations of the present invention. Any modifications, additions, or substitutions made by persons skilled in the art to the described embodiments, as long as they do not deviate from the invention or exceed the scope defined by the claims, shall fall within the scope of protection of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0072] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A paper fiber aluminum cover for circuit board drilling, consisting of an aluminum sheet and a paper fiber composite layer, characterized in that: The paper fiber composite layer comprises, by weight percentage, 38-46 wt% of paper fiber, 3.5-4.5 wt% of a compatibilizing lubricant, 4.5-7 wt% of a tackifier, and 0.12-0.15 wt% of an antioxidant, with the remainder being polylactic acid resin; The compatibilized lubricant is prepared by the following method: Step A1: Mix dihydroxyl silicone oil, triethylamine, and anhydrous dioxane, introduce dry gas protection, control the temperature of the water bath at 20-35°C, stir and slowly add methylvinyldichlorosilane, react for 1.5-2.2 hours, then add p-fluorobenzoyl chloride, mix, heat to 70-90°C, react for 1-1.5 hours, and remove dioxane by vacuum rotary evaporation after the reaction. Wash the substrate with water and dry it to obtain an intermediate; Step A2: Mix the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile and anhydrous toluene, heat to 60-70°C and stir to activate for 30-50 minutes, then stop heating and apply 150-200W / m 2 The reaction was continued under ultraviolet irradiation for 3-4 hours. After the reaction was completed, the toluene was removed by vacuum rotary evaporation to obtain a compatibilized lubricant.

2. The paper fiber aluminum cover for circuit board drilling according to claim 1, characterized in that: The feeding ratio of the hydroxyl content of the double-terminal hydroxyl silicone oil, methylvinyldichlorosilane, p-fluorobenzoyl chloride, triethylamine and anhydrous dioxane is 0.1mmol:30-40mmol:25-50mmol:15-25mL:180-260mL.

3. The paper fiber aluminum cover for circuit board drilling according to claim 2, characterized in that: The average molecular weight of the double-terminal hydroxy silicone oil is not higher than 2000.

4. The paper fiber aluminum cover for circuit board drilling according to claim 3, characterized in that: The feed ratio of the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile and anhydrous toluene is 50 g: 10-18 mmol: 20-30 mg: 100-150 mL.

5. A method for preparing a paper fiber aluminum cover sheet for circuit board drilling according to any one of claims 1 to 4, characterized in that: The steps include: Step S1: mixing polylactic acid resin, paper fiber, compatibilizer lubricant, tackifier and antioxidant, melt-kneading and crushing the mixture to obtain a composite masterbatch; Step S2: plasticize and extrude the composite masterbatch, scrape the plasticized melt onto the surface of the preheated aluminum sheet, and then roll it to determine the thickness and cool it to form a paper fiber composite layer on the surface of the aluminum sheet. After cutting and deburring, it is made into a paper fiber aluminum cover plate.

6. The method for preparing a paper fiber aluminum cover sheet for circuit board drilling according to claim 5, characterized in that: The tackifier is terpene resin, and the softening temperature is not higher than 120°C.

7. The method for preparing a paper fiber aluminum cover sheet for circuit board drilling according to claim 5, characterized in that: The discharge temperature of the plasticized melt of the composite masterbatch is 195±5℃, and the mold temperature for rolling and thickness setting is 120-140℃.

8. The method for preparing a paper fiber aluminum cover sheet for circuit board drilling according to claim 5, characterized in that: The thickness of the paper fiber composite layer is 0.9-1.6 times that of the aluminum sheet.

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