A paper fiber aluminum cover plate for circuit board drilling and a preparation method thereof

Abstract

The present application relates to a kind of paper fiber aluminum cover plate for circuit board drilling and its preparation method, belong to composite material technical field.The aluminum cover plate is composed of aluminum sheet and paper fiber composite layer, wherein, paper fiber composite layer includes by weight percentage: paper fiber 38-46wt%, compatibilized lubricant 3.5-4.5wt%, tackifier 4.5-7wt% and antioxidant 0.12-0.15wt%, the rest is polylactic acid resin;Compatibilized lubricant is replaced by double-end hydroxyl silicone oil and methyl vinyl dichlorosilane, then by p-fluorobenzoyl chloride and end residual hydroxyl reaction end-capping, introduce end fluorine benzene structure modification, again by γ-mercapto propyl triethoxysilane and the vinyl structure addition on the side chain of intermediate side chain, introduce side chain ethoxysilane structure modification;Compatibilized lubricant reduces the friction of polylactic acid and paper fiber, and the friction between the macromolecules of polylactic acid in the near surface layer of paper fiber, improves drilling precision, reduces drilling broken needle rate.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a paper fiber aluminum cover plate for drilling circuit boards and its preparation method. Background Technology

[0002] Back drilling of circuit boards is a technique 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, prevent scratches on the surface, suppress exit burrs on the surface of the circuit board, and improve drilling accuracy.

[0003] Traditional circuit board cover plates use aluminum sheets, which have good thermal conductivity, helping to dissipate heat and reduce heat accumulation caused by friction during drilling. They are also relatively inexpensive. However, the smooth surface of aluminum sheets makes them prone to slippage during drilling, leading to poor positioning and low hole accuracy. Therefore, various composite cover plates have been developed, such as resin composite cover plates, including phenolic resin composite cover plates and epoxy resin composite cover plates. These composite cover plates effectively solve the problem of aluminum sheet slippage during drilling. However, the waste material after drilling is difficult to process and easily causes environmental pollution, leading to their gradual elimination from the market. Currently, resin is used to coat and impregnate biodegradable paper materials. The process of encapsulating the paper with aluminum sheets and then bonding it to reduce the amount of resin used to some extent, thus alleviating environmental pressure. However, the composite resin material is still difficult to process, resulting in complicated post-processing of the paper. Furthermore, during the drilling process, the drill bit must pass through at least the resin layer, paper layer, adhesive layer, and aluminum sheet layer. The friction between each layer is different, which can easily lead to uneven stress on the drill bit, causing it to deviate and making it difficult to improve drilling accuracy. Polylactic acid (PLA) is a biodegradable material that has excellent application prospects when combined with existing paper fibers as a cover plate. However, in practical applications, it has been found that PLA has a high coefficient of friction, especially after being combined with paper fibers, which can easily cause entanglement and affect drilling accuracy. Summary of the Invention

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

[0005] The objective of this invention can be achieved through the following technical solutions:

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

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

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

[0009] Step S1: Mix and feed polylactic acid resin, paper fiber, compatibilizer, lubricant, tackifier and antioxidant into the mixture, melt and knead it, then discharge and crush it to obtain composite masterbatch;

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

[0011] Furthermore, the plasticized melt discharge temperature of the composite masterbatch is 195±5℃, and the mold temperature for rolling thickness determination is 120-140℃. Under this temperature control, the forming 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 compatibilizing lubricant is prepared by the following method:

[0014] Step A1: Mix the hydroxyl-terminated silicone oil, triethylamine, and anhydrous dioxane, purge with dry gas, maintain the temperature in a water bath at 20-35℃, stir at 120-180 rpm, slowly add methyl vinyl dichlorosilane and react for 1.5-2.2 h, then add p-fluorobenzoyl chloride and mix, raise the temperature to 70-90℃ and react for 1-1.5 h. After the reaction is complete, remove the dioxane by rotary evaporation under reduced pressure, wash the substrate with water and dry to obtain the intermediate;

[0015] Furthermore, the hydroxyl content of the double-hydroxyl-terminated silicone oil, and the feeding ratio of methyl vinyl dichlorosilane, p-fluorobenzoyl chloride, triethylamine, and anhydrous dioxane are 0.1 mmol: 30-40 mmol: 25-50 mmol: 15-25 mL: 180-260 mL. The double-hydroxyl-terminated silicone oil reacts with methyl vinyl dichlorosilane to form an organosilicon oligomer containing vinyl blocks. Then, p-fluorobenzoyl chloride reacts with the residual terminal hydroxyl groups to seal the end, introducing terminal fluorobenzene structure modification.

[0016] Furthermore, the average molecular weight of the double-hydroxyl-terminated silicone oil is no higher than 2000, it has good reactivity, and it 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℃, and activate by stirring at 90-120 rpm for 30-50 min. Then stop heating and apply 150-200 W / m 2The reaction was continued for 3-4 hours under ultraviolet irradiation. After the reaction was completed, toluene was removed by rotary evaporation under reduced pressure to obtain the compatibilizing 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 radicals that activate double bonds and thiol groups. Subsequently, under UV irradiation, the activated double bonds and thiol groups undergo addition, introducing ethoxysilane structural modification into the side chain of the intermediate molecule.

[0019] The beneficial effects of this invention are:

[0020] The aluminum cover plate of the present invention uses 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 material used. Moreover, both polylactic acid and paper fiber are biodegradable materials. Compared with existing coated cover plates, coated paper composite cover plates, etc., drilling waste is easier to process and causes less environmental pollution.

[0021] This invention discloses a compatibilizing lubricant suitable for polylactic acid and paper fiber composites. It comprises a silicone oligomer containing vinyl blocks, formed by replacing a bihydroxyl-terminated silicone oil with methyl vinyl dichlorosilane. Subsequently, the oligomer is capped by reacting p-fluorobenzoyl chloride with the residual terminal hydroxyl groups, introducing a terminal fluorobenzene structure modification to form an intermediate. Then, γ-mercaptopropyltriethoxysilane is added to the vinyl structure on the side chain of the intermediate, introducing a side chain ethoxysilane structure modification. During melt mixing, the compatibilizing lubricant couples with the paper fibers, introducing macromolecular organosilicon chains into the surface of the paper fibers, reducing the friction between the paper fibers and polylactic acid, and the terminal fluorobenzene structure... Dispersed between the paper fiber and polylactic acid (PLA) bonding layers, the friction between PLA macromolecular chains in the bonding layer is reduced, thus ensuring sufficient lubrication of both the paper fiber and PLA. On the one hand, this increases the proportion of paper fiber in the composite layer, fully utilizing the reinforcing effect of the paper fiber. During drilling, the composite layer is less prone to deformation, reducing drill bit deviation caused by the composite layer. On the other hand, the drill bit can slide sufficiently when in contact with the paper fiber, reducing drill bit deviation caused by paper fiber entanglement, thereby achieving higher drilling accuracy. In addition, thanks to the improved lubrication and anti-entanglement properties of the compatibilizer, the drilling resistance of the drill bit is effectively reduced, resulting in lower drill bit wear and a lower drill bit breakage rate. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1: Preparation of paper fiber aluminum cover plate, as detailed below:

[0024] (1) Preparation of compatibilizing lubricants

[0025] Step A1: Mix bihydroxyl-terminated silicone oil, triethylamine, and anhydrous dioxane, purge with dry nitrogen, maintain the temperature in a water bath at 20°C, stir at 120 rpm, slowly add methylvinyl dichlorosilane and react for 2.2 h, then add p-fluorobenzoyl chloride and mix, raise the temperature to 70°C and react for 1.5 h. The bihydroxyl-terminated silicone oil is selected from IOTA 2110 type raw material with a molecular weight of 1000. The hydroxyl content of the bihydroxyl-terminated silicone oil and the feed ratio of methylvinyl dichlorosilane, p-fluorobenzoyl chloride, triethylamine, and anhydrous dioxane are 0.1 mmol: 40 mmol: 25 mmol: 15 mL: 180 mL. After the reaction is completed, remove dioxane by rotary evaporation under reduced pressure, wash the substrate with water and dry to obtain the intermediate.

[0026] Step A2: Mix the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile, and anhydrous toluene, heat to 60°C, and activate by stirring at 90 rpm for 50 min. Then stop heating and apply 150 W / m 2 The reaction was continued for 4 hours under ultraviolet irradiation. 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, toluene was removed by rotary evaporation under reduced pressure to obtain the compatibilizing lubricant.

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

[0028] The raw materials are calculated by weight percentage as follows: 38 wt% paper fiber, selected from commercially available wood pulp paper fiber; 3.5 wt% compatibilizer and lubricant, prepared in this embodiment; and 7 wt% tackifier, selected from... M105 type terpene resin with a softening temperature of 105℃; 0.12wt% antioxidant, selected from antioxidant 1010 and antioxidant 168 in equal weight ratio; the balance is polylactic acid resin, using JSC-710H type resin raw material.

[0029] Step S1: Mix polylactic acid resin, paper fiber, compatibilizer, lubricant, tackifier and antioxidant and feed them into the mixture. Melt and knead at 180°C until the torque is stable. Discharge, cool and crush to obtain composite masterbatch.

[0030] Step S2: Plasticize and extrude the composite masterbatch using a twin-screw extruder, controlling the discharge temperature of the plasticized melt to 195±5℃. Preheat the aluminum sheet to 220±10℃, scrape the plasticized melt onto the surface of the preheated aluminum sheet, and then roll it to a fixed thickness. The die temperature of the rolling die is 140℃. After cooling and forming, a paper fiber composite layer is formed on the surface of the aluminum sheet. After cutting and deburring, a paper fiber aluminum cover plate is made.

[0031] Example 2: Preparation of paper fiber aluminum cover plate, as detailed below:

[0032] (1) Preparation of compatibilizing lubricants

[0033] Step A1: Mix bihydroxyl-terminated silicone oil, triethylamine, and anhydrous dioxane, purge with dry nitrogen, maintain the temperature in a water bath at 35°C, stir at 180 rpm, slowly add methyl vinyl dichlorosilane and react for 1.5 h, then add p-fluorobenzoyl chloride and mix, raise the temperature to 90°C and react for 1 h. The bihydroxyl-terminated silicone oil is selected from IOTA 2110 type raw material with a molecular weight of 2000. The hydroxyl content of the bihydroxyl-terminated silicone oil and the feed ratio of methyl vinyl dichlorosilane, p-fluorobenzoyl chloride, triethylamine, and anhydrous dioxane are 0.1 mmol: 30 mmol: 50 mmol: 25 mL: 260 mL. After the reaction is completed, remove dioxane by rotary evaporation under reduced pressure, wash the substrate with water and dry to obtain the intermediate.

[0034] Step A2: Mix the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile, and anhydrous toluene, heat to 70°C, and activate by stirring at 120 rpm for 30 min. Then stop heating and apply 200 W / m 2 The reaction was continued for 3 hours under ultraviolet irradiation. 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, toluene was removed by rotary evaporation under reduced pressure to obtain the compatibilizing lubricant.

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

[0036] The raw materials are calculated by weight percentage as follows: 46 wt% paper fiber, selected from commercially available wood pulp paper fiber; 4.5 wt% compatibilizer and lubricant, prepared in this embodiment; and 4.5 wt% tackifier, selected from... M105 type terpene resin with a softening temperature of 105℃; 0.15wt% antioxidant, selected from antioxidant 1010 and antioxidant 168 in equal weight ratio; the balance is polylactic acid resin, using JSC-710H type resin raw material.

[0037] Step S1: Mix polylactic acid resin, paper fiber, compatibilizer, lubricant, tackifier and antioxidant and feed them into the mixture. Melt and knead at 180°C until the torque is stable. Discharge, cool and crush to obtain composite masterbatch.

[0038] Step S2: Plasticize and extrude the composite masterbatch using a twin-screw extruder, controlling the discharge temperature of the plasticized melt to 195±5℃. Preheat the aluminum sheet to 220±10℃, scrape the plasticized melt onto the surface of the preheated aluminum sheet, and then roll it to a fixed thickness. The die temperature of the rolling die is 120℃. After cooling and forming, a paper fiber composite layer is formed on the surface of the aluminum sheet. After cutting and deburring, a paper fiber aluminum cover plate is made.

[0039] Example 3: Preparation of paper fiber aluminum cover plate, as detailed below:

[0040] (1) Preparation of compatibilizing lubricants

[0041] Step A1: Mix bihydroxyl-terminated silicone oil, triethylamine, and anhydrous dioxane, purge with dry nitrogen, maintain the temperature in a water bath at 25°C, stir at 120 rpm, slowly add methyl vinyl dichlorosilane and react for 2 hours, then add p-fluorobenzoyl chloride and mix, raise the temperature to 90°C and react for 1.2 hours. The bihydroxyl-terminated silicone oil is selected from IOTA 2110 type raw material with a molecular weight of 1000. The hydroxyl content of the bihydroxyl-terminated silicone oil and the feed ratio of methyl vinyl dichlorosilane, p-fluorobenzoyl chloride, triethylamine, and anhydrous dioxane are 0.1 mmol: 35 mmol: 30 mmol: 20 mL: 200 mL. After the reaction is completed, remove dioxane by rotary evaporation under reduced pressure, wash the substrate with water and dry to obtain the intermediate.

[0042] Step A2: Mix the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile, and anhydrous toluene, heat to 60°C, and activate by stirring at 120 rpm for 50 min. Then stop heating and apply 150 W / m 2 The reaction was continued under ultraviolet irradiation for 3.2 h. 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, toluene was removed by rotary evaporation under reduced pressure to obtain the compatibilizing lubricant.

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

[0044] The raw materials are calculated by weight percentage as follows: 40 wt% paper fiber, selected from commercially available wood pulp paper fiber; 3.8 wt% compatibilizer and lubricant, prepared in this embodiment; and 5.8 wt% tackifier, selected from... M105 type terpene resin with a softening temperature of 105℃; 0.15wt% antioxidant, selected from antioxidant 1010 and antioxidant 168 in equal weight ratio; the balance is polylactic acid resin, using JSC-710H type resin raw material.

[0045] Step S1: Mix polylactic acid resin, paper fiber, compatibilizer, lubricant, tackifier and antioxidant and feed them into the mixture. Melt and knead at 180°C until the torque is stable. Discharge, cool and crush to obtain composite masterbatch.

[0046] Step S2: Plasticize and extrude the composite masterbatch using a twin-screw extruder, controlling the discharge temperature of the plasticized melt to 195±5℃. Preheat the aluminum sheet to 220±10℃, scrape the plasticized melt onto the surface of the preheated aluminum sheet, and then roll it to a fixed thickness. The die temperature of the rolling die is 130℃. After cooling and forming, a paper fiber composite layer is formed on the surface of the aluminum sheet. After cutting and deburring, a paper fiber aluminum cover plate is made.

[0047] Example 4: Preparation of paper fiber aluminum cover plate, as detailed below:

[0048] (1) Preparation of compatibilizing lubricants

[0049] Step A1: Mix bihydroxyl-terminated silicone oil, triethylamine, and anhydrous dioxane, purge with dry nitrogen, maintain the temperature in a water bath at 30°C, stir at 180 rpm, slowly add methyl vinyl dichlorosilane and react for 1.8 h, then add p-fluorobenzoyl chloride and mix, raise the temperature to 80°C and react for 1.5 h. The bihydroxyl-terminated silicone oil is selected from IOTA 2110 type raw material with a molecular weight of 2000. The hydroxyl content of the bihydroxyl-terminated silicone oil and the feed ratio of methyl vinyl dichlorosilane, p-fluorobenzoyl chloride, triethylamine, and anhydrous dioxane are 0.1 mmol: 35 mmol: 30 mmol: 20 mL: 240 mL. After the reaction is completed, remove dioxane by rotary evaporation under reduced pressure, wash the substrate with water and dry to obtain the intermediate.

[0050] Step A2: Mix the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile, and anhydrous toluene, heat to 70°C, and activate by stirring at 120 rpm for 50 min. Then stop heating and apply 150 W / m 2 The reaction was continued under ultraviolet irradiation for 3.5 h. 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, toluene was removed by rotary evaporation under reduced pressure to obtain the compatibilizing lubricant.

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

[0052] The raw materials are calculated by weight percentage as follows: 43 wt% paper fiber, selected from commercially available wood pulp paper fiber; 4 wt% compatibilizer and lubricant, prepared in this embodiment; and 6.2 wt% tackifier, selected from... M105 type terpene resin with a softening temperature of 105℃; 0.13wt% antioxidant, selected from antioxidant 1010 and antioxidant 168 in equal weight ratio; the balance is polylactic acid resin, using JSC-710H type resin raw material.

[0053] Step S1: Mix polylactic acid resin, paper fiber, compatibilizer, lubricant, tackifier and antioxidant and feed them into the mixture. Melt and knead at 180°C until the torque is stable. Discharge, cool and crush to obtain composite masterbatch.

[0054] Step S2: Plasticize and extrude the composite masterbatch using a twin-screw extruder, controlling the discharge temperature of the plasticized melt to 195±5℃. Preheat the aluminum sheet to 220±10℃, scrape the plasticized melt onto the surface of the preheated aluminum sheet, and then roll it to a fixed thickness. The die temperature of the rolling die is 130℃. After cooling and forming, a paper fiber composite layer is formed on the surface of the aluminum sheet. After cutting and deburring, a paper fiber aluminum cover plate is made.

[0055] Comparative Example 1: This comparative example is based on Example 4, but without the addition of paper fibers and compatibilizers, and the polylactic acid resin is added to 100 wt%. The rest of the implementation process is exactly the same.

[0056] Comparative Example 2 is the same as Example 4, except that the compatibilizing lubricant was replaced with 1 wt% of silane coupling agent KH-570, 2 wt% of PL-218 silicone powder and 1 wt% of TPW604 lubricant, and the rest of the implementation process was exactly the same.

[0057] Samples were taken from the aluminum cover plate prepared above, and the thickness (H0) of the aluminum sheet and the thickness (H1) of the composite layer were measured, 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 0.2mm aluminum sheet prepared above were used as comparative example 3 to conduct drilling tests on the PCB board. The hole diameters were 0.1mm, 0.15mm and 0.2mm, respectively. The specific test data are shown in Tables 2-4.

[0062] Table 20.1mm Drilling Test Results

[0063] Average error / mil Maximum error / mil CPK value Drill failure 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 failure 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 40.2mm Drilling Test Results

[0067]

[0068]

[0069] As can be seen from the test results in Tables 2-4, the paper fiber aluminum cover plate prepared in the example is used in the drilling of circuit boards, and the drilling accuracy is high and the breakage rate is low.

[0070] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above 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 one or more embodiments or examples.

[0071] The above description is merely illustrative and explanatory of the present invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not depart from the invention or exceed the scope defined by the claims, all of which should fall within the protection scope of the present invention. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0072] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A paper fiber aluminum cover plate for drilling circuit boards, comprising an aluminum sheet and a paper fiber composite layer, characterized in that, The paper fiber composite layer comprises, by weight percentage: 38-46 wt% paper fiber, 3.5-4.5 wt% compatibilizer and lubricant, 4.5-7 wt% tackifier and 0.12-0.15 wt% antioxidant, with the balance being polylactic acid resin; The compatibilizing lubricant is prepared by the following method: Step A1: Mix the hydroxyl-terminated silicone oil, triethylamine, and anhydrous dioxane, purge with dry gas, control the temperature in a water bath at 20-35℃, stir and slowly add methyl vinyl dichlorosilane, react for 1.5-2.2h, then add p-fluorobenzoyl chloride and mix, raise the temperature to 70-90℃ and react for 1-1.5h. After the reaction is complete, remove the dioxane by rotary evaporation under reduced pressure, wash the substrate with water and dry to obtain the intermediate; Step A2: Mix the intermediate, γ-mercaptopropyltriethoxysilane, azobisisobutyronitrile, and anhydrous toluene, heat to 60-70℃ and stir for 30-50 min to activate. Then stop heating and apply 150-200 W / m 2 The reaction was continued for 3-4 hours under ultraviolet irradiation. After the reaction was completed, toluene was removed by rotary evaporation under reduced pressure to obtain the compatibilizing lubricant.

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

3. The paper fiber aluminum cover plate for drilling circuit boards according to claim 2, characterized in that, The average molecular weight of dual-hydroxyl-terminated silicone oils is no higher than 2000.

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

5. A method for preparing a paper fiber aluminum cover plate for drilling circuit boards according to any one of claims 1-4, characterized in that, Includes the following steps: Step S1: Mix and feed polylactic acid resin, paper fiber, compatibilizer, lubricant, tackifier and antioxidant into the mixture, melt and knead it, then discharge and crush it to obtain composite masterbatch; Step S2: Plasticize and extrude the composite masterbatch, and scrape the plasticized melt onto the surface of the preheated aluminum sheet. Then, roll it to a fixed thickness and cool it to form a paper fiber composite layer on the surface of the aluminum sheet. After cutting and deburring, the paper fiber aluminum cover plate is made.

6. The method for preparing a paper fiber aluminum cover plate for drilling circuit boards according to claim 5, characterized in that, The tackifier is a terpene resin with a softening temperature not exceeding 120℃.

7. The method for preparing a paper fiber aluminum cover plate for drilling circuit boards according to claim 5, characterized in that, The plasticized melt discharge temperature of the composite masterbatch is 195±5℃, and the mold temperature for roll forming is 120-140℃.

8. The method for preparing a paper fiber aluminum cover plate for drilling circuit boards 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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