An impregnation system and impregnation method for enhancing the wettability of prepreg

Abstract

The present invention relates to an impregnation system and an impregnation method for enhancing the wettability of prepreg, comprising a prepreg device, a main impregnation device and a glue liquid circulation device, wherein the prepreg passes through the prepreg device and the main impregnation device in sequence for impregnation; wherein the prepreg device comprises a prepreg tank, a rolling and tensioning guide roller and a hollow gluing guide roller, wherein the convex block on the rolling and tensioning guide roller presses the prepreg, causing the prepreg to become loose and then enter the prepreg tank for gluing, and at this time, the hollow gluing guide roller is pressurized by a first pump body in the glue liquid circulation device through a first pipeline to inject glue into the hollow cavity of the hollow gluing guide roller, and the glue is ejected from the liquid outlet to glue the prepreg, so that the rolling and tensioning guide roller and the hollow gluing guide roller not only have a tensioning effect, but also can cause the prepreg to be loosened first and then sprayed with glue for infiltration, effectively ensuring that the glue can smoothly penetrate into the prepreg, thereby improving the wettability of the prepreg.

Description

Technical Field

[0001] The present invention relates to the field of impregnation in the production of prepregs in copper clad laminates, and in particular to an impregnation system and an impregnation method for enhancing the wettability of prepregs. Background Art

[0002] As we all know, copper-clad laminate (CCL) is the fundamental material for printed circuit boards (PCBs). It's a sheet material made by impregnating prepreg (such as fiberglass cloth / paper or other reinforcing materials) with resin, curing it to form a prepreg, then coating one or both sides with copper foil and heat-pressing it. The key to a CCL's excellent performance lies in the prepreg processing, making the wetness between the prepreg and the resin particularly important.

[0003] Currently, PCB suppliers are placing increasingly high demands on the reliability of copper-clad laminates. Improving the wettability of prepregs during production is a primary approach used by the industry. Traditionally, there are two approaches to addressing this issue: one is to reduce the gluing machine line speed, thereby increasing the contact time between the prepreg and the glue to improve wettability. This significantly reduces gluing efficiency and reduces production capacity. The other is to reduce the glue viscosity to increase the prepreg's impregnation, but this can lead to poor prepreg appearance and other issues such as sag.

[0004] In view of the limitations of the above-mentioned method, the industry has also paid attention to improving the impregnation equipment. The basic principle of the existing impregnation equipment is to pass the prepreg through the impregnation tank under the action of a traction machine and a guide roller and contact and penetrate the glue in the tank to finally complete the impregnation. The guide rollers are all smooth and only play a role in tensioning the prepreg. For the improved impregnation equipment, reference can be made to the device disclosed in Chinese patent CN201362800Y for improving the wettability of the semi-cured sheet. The device is provided with a small trapezoidal groove with a downward opening in the large trapezoidal groove opening filled with glue. The opening of the small trapezoidal groove is immersed below the surface of the glue liquid to form a closed cavity. The air is continuously discharged by a vacuum pump to form a certain negative pressure in the cavity to discharge the air in the reinforcing material, thereby improving the wettability of the reinforcing material. However, adding an additional small trapezoidal groove in the large trapezoidal groove to form a closed cavity not only makes the overall structure complicated, but the small trapezoidal groove will also hinder the fluidity of the glue, especially during the vacuuming process, which will affect the full contact between the reinforcing material and the glue, which is obviously not conducive to better impregnation. Therefore, the industry urgently needs to study a method that can enhance the wetting of prepregs. Summary of the Invention

[0005] The present invention aims to address the shortcomings of the above-mentioned existing technologies and its main purpose is to provide an impregnation system and an impregnation method for enhancing the wettability of prepregs. The system loosens the prepregs before gluing them through the combination of a rolling tensioning guide roller and a hollow gluing guide roller, thereby improving the wettability of the prepregs.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0007] A wetting system for enhancing the wettability of prepregs, comprising a prepreg device, a main impregnation device and a glue circulation device, wherein the prepregs are sequentially impregnated through the prepreg device and the main impregnation device; wherein the prepreg device comprises a prepreg tank; a rolling tensioning guide roller, which is installed at the entrance of the prepreg tank, wherein the outer peripheral wall surface of the rolling tensioning guide roller is provided with a protrusion which can press against the prepreg and make the prepreg loose; a hollow gluing guide roller, which is installed in the prepreg tank, wherein the hollow gluing guide roller has a hollow cavity, and a plurality of holes for the prepreg to be applied are opened on the outer peripheral wall of the hollow gluing guide roller. The glue outlet holes are all connected to the hollow cavity; the glue circulation device includes a glue storage tank; a first pump body, which is connected to the glue storage tank and the hollow glue guide roller through a first pipe, and pressurizes the glue in the glue storage tank and injects it into the hollow glue guide roller, wherein the glue inlet end of the first pipe is connected to the glue storage tank, and the glue outlet end is connected to the port of the hollow glue guide roller; a second pump body, which is connected to the glue storage tank and the prepreg tank through a second pipe, and circulates the glue in the prepreg tank to the glue storage tank, wherein the glue inlet of the second pipe is connected to the prepreg tank, and the glue outlet is connected to the glue storage tank.

[0008] Furthermore, the main immersion device includes a main immersion tank, an upper tensioning roller, a lower tensioning roller and an extrusion roller. The upper tensioning roller is installed at the entrance of the main immersion tank, the lower tensioning roller is installed in the main immersion tank, and the extrusion roller is installed at the outlet of the main immersion tank. The prepreg after being impregnated in the prepreg tank passes through the upper tensioning roller to the lower tensioning roller and enters the main immersion tank. The prepreg after being impregnated in the main immersion tank is taken out by the extrusion roller.

[0009] Furthermore, the viscosity of the glue in the pre-impregnation tank is lower than the viscosity of the glue in the main impregnation tank.

[0010] Furthermore, the glue inlet end of the first pipe is connected to the bottom of the glue storage tank, and the glue inlet of the second pipe is connected to the bottom of the prepreg tank.

[0011] Furthermore, the glue outlet hole is a circular hole with a diameter of 0.001-100 mm.

[0012] Furthermore, the bump is a cone with a height of 0.001-1 mm.

[0013] Furthermore, a plurality of rolling and tensioning guide rollers are arranged along the feeding direction, and the height of the protrusions on each rolling and tensioning guide roller along the feeding direction increases step by step.

[0014] A wetting method for enhancing the wettability of prepregs, comprising the following specific steps: a. prepregs enter through a rolling and tensioning guide roller, where convex blocks on the outer peripheral wall surface of the rolling and tensioning guide roller press the prepregs to loosen them in advance; b. the loosened prepregs enter a prepreg tank through a hollow gluing guide roller, where a first pump pressurizes glue in a liquid storage tank and injects it into the hollow cavity of the hollow gluing guide roller, where the glue is applied to the prepregs through a glue outlet hole; and c. the glued prepregs enter a main impregnation device for further infiltration.

[0015] Furthermore, in step a, a plurality of rolling and tensioning guide rollers are arranged in the feeding direction, so that the height of the protrusions of each rolling and tensioning guide roller increases step by step along the feeding direction, so that the prepreg gradually becomes loose.

[0016] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, the prepreg is pressed by the convex blocks on the rolling tensioning guide roller, so that the prepreg becomes loose and then enters the prepreg tank for gluing. At this time, the hollow gluing guide roller is pressurized by the first pump body in the glue circulation device through the first pipe to inject glue into the hollow cavity, and the glue is ejected from the liquid outlet to glue the prepreg. In this way, the rolling tensioning guide roller and the hollow gluing guide roller not only have a tensioning effect, but also can make the prepreg loose first and then spray glue for infiltration, which can effectively ensure that the glue can smoothly penetrate into the prepreg, thereby improving the wettability of the prepreg. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the infiltration device of the present invention;

[0018] Figure 2 This is a schematic structural diagram of the calendering guide roller of the present invention;

[0019] Figure 3 It is a structural schematic diagram of the gluing guide roller of the present invention.

[0020] Description of Figure Numbers:

[0021] 10. Prepreg device 11. Prepreg tank

[0022] 12. Rolling tension guide roller 121, bump

[0023] 13. Hollow glue guide roller 131, hollow cavity

[0024] 132, glue hole 14, glue liquid

[0025] 20. Main immersion device 21. Main immersion tank

[0026] 22. Upper tension roller 23. Lower tension roller

[0027] 24. Squeeze roller 25. Glue

[0028] 30. Glue circulation device 31. Glue storage tank

[0029] 32. First pump body 32. Second pump body

[0030] 33. First pipeline 34. Second pipeline

[0031] 35. Glue

[0032] 40. Prepreg. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0034] See also Figures 1 to 3 As shown, a wetting system for enhancing the wettability of prepregs includes a prepreg device 10, a main impregnation device 20, and a glue circulation device 30. The prepreg 40 is impregnated in the prepreg device 10 and the main impregnation device 20 in sequence, wherein:

[0035] The prepreg device 10 includes a prepreg tank 11, a rolling tensioning guide roller 12, and a hollow glue guide roller 13. The prepreg tank 11 contains a low-viscosity glue 14 for prepreg impregnation. The rolling tensioning guide roller 12 is installed at the entrance of the prepreg tank 11. The outer peripheral wall surface of the rolling tensioning guide roller 12 is provided with a plurality of protrusions 121. When the prepreg passes around the rolling tensioning guide roller 12, the protrusions 121 press against the prepreg and make the prepreg loose. In this way, the rolling tensioning guide roller 12 plays the role of tensioning the prepreg and also plays the role of pressing and loosening the prepreg. The protrusions 121 are cones with a height of 0.001-1mm. Furthermore, the rolling tensioning guide roller Multiple rollers 12 (two in this embodiment) can be arranged along the feed direction, and the height of the protrusions 121 on each rolling and tensioning guide roller 12 increases stepwise along the feed direction. That is, the protrusion height on each adjacent rolling and tensioning guide roller is smaller than the protrusion height on the next rolling and tensioning guide roller along the feed direction. This gradually loosens the prepreg as it passes through each rolling and tensioning guide roller, protecting it from sudden stress damage and facilitating subsequent adhesive infiltration. The hollow adhesive guide roller 13, installed in the prepreg tank 11, also serves to tension the prepreg. The hollow gluing guide roller 13 has a hollow cavity 131, and a plurality of glue outlet holes 132 for gluing prepreg are opened on the outer peripheral wall of the hollow gluing guide roller 13. The glue outlet holes 132 are all connected to the hollow cavity 131, so that the glue entering the hollow gluing guide roller 13 can be ejected from the glue outlet holes 132. The glue outlet holes 132 can be circular holes with a diameter of 0.001-100 mm, and the specific size can be designed according to actual needs.

[0036] The main impregnation device 20 includes a main impregnation tank 21, an upper tensioning roller 22, a lower tensioning roller 23, and a squeeze roller 24. The main impregnation tank 21 contains a higher viscosity glue 25 than the glue in the prepreg tank 11. This allows the prepreg to enter the low-viscosity glue first and then the high-viscosity glue, improving the impregnation effect. The upper tensioning roller 22 is installed at the entrance of the main impregnation tank 11, the lower tensioning roller 22 is installed inside the main impregnation tank 11, and the squeeze roller 24 is installed at the exit of the main impregnation tank 21. After being impregnated in the prepreg tank, the prepreg 40 passes through the upper tensioning roller and the lower tensioning roller and enters the main impregnation tank 21. After being impregnated in the main impregnation tank 21, the prepreg is carried out by the squeeze rollers 23 and 4.

[0037] The glue circulation device 30 includes a glue storage tank 31, a first pump body 32, and a second pump body 33. The glue 35 in the glue storage tank 31 is circulated with the glue 14 in the prepreg tank 11. The first pump body 32 connects the glue storage tank 31 and the hollow glue guide roller 13 via a first pipe 34. The first pump body 32 pressurizes the glue in the glue storage tank 31 and injects it into the hollow cavity 131 in the hollow glue guide roller 13. The specific power of the first pump body 32 can be determined according to actual needs and is not described in detail here. The glue inlet end of the first pipe 34 is connected to the glue storage tank 31, preferably to the bottom of the glue storage tank 31 to facilitate the first pump body to extract the glue. The glue outlet end of the first pipe 34 is connected to the end of the hollow cavity 131 of the hollow glue guide roller 13. The second pump body 33 is connected to the glue storage tank 31 and the prepreg tank 13 through the second pipe 35, and circulates the glue in the prepreg tank 13 to the glue storage tank 31, wherein the glue inlet of the second pipe 33 is connected to the prepreg tank 13, preferably the glue inlet of the second pipe 33 is connected to the bottom of the prepreg tank 13, which can also better extract the glue in the prepreg tank. The glue outlet 33 of the second pipe is connected to the glue storage tank 31.

[0038] The specific impregnation method is as follows: The prepreg 40 enters through the rolling and tensioning guide roller 12. The protrusions 121 on the outer peripheral surface of the rolling and tensioning guide roller 12 press the prepreg 40, loosening it in advance. At the same time, the rolling and tensioning guide roller 12 also tensions the prepreg 40. In this embodiment, two rolling and tensioning guide rollers 12 are used, and the height of their protrusions increases gradually along the feeding direction, which can gradually press and loosen the prepreg 40. After passing through the rolling and tensioning guide roller 12, the prepreg enters the prepreg tank 11 via the hollow gluing guide roller 13 for impregnation. At this point, the first pump body 32 pressurizes the glue in the liquid reservoir 31 and injects it into the hollow cavity 131 of the hollow gluing guide roller 13. The glue is then ejected through the glue outlet 132 to coat the prepreg. Since the prepreg has been processed into a relatively loose shape by the rolling and tensioning guide roller 12, the glue ejected through the glue outlet 132 easily penetrates the prepreg, thereby enhancing the impregnation effect. Finally, the glued prepreg enters the main impregnation device 20 for further impregnation. When the glue in the prepreg tank reaches a certain level, the second pump body is activated to pump the excess glue in the prepreg tank into the liquid reservoir for recycling.

[0039] The design focus of the present invention is to press the prepreg by rolling the convex blocks on the tensioning guide roller, so that the prepreg becomes loose and then enters the prepreg tank for gluing. At this time, the hollow gluing guide roller is pressurized by the first pump body in the glue circulation device through the first pipe to inject glue into the hollow cavity, and then ejected from the liquid outlet to glue the prepreg. This can effectively ensure that the glue can be smoothly immersed in the prepreg, thereby improving the wettability of the prepreg.

[0040] The above description is merely a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An impregnation system for enhancing the wettability of prepreg, comprising a prepreg device and a main impregnation device, wherein the prepreg is impregnated sequentially through the prepreg device and the main impregnation device, characterized in that: Also includes a glue circulation device; in The prepreg device comprises: a prepreg tank; A rolling tensioning guide roller is installed at the entrance of the prepreg tank, and a convex block is provided on the outer peripheral wall surface of the rolling tensioning guide roller to press against the prepreg and loosen the prepreg; The rolling tensioning guide rollers are arranged in plurality along the feeding direction, and the height of the protrusions on each rolling tensioning guide roller along the feeding direction increases step by step; A hollow gluing guide roller is installed in the prepreg tank. The hollow gluing guide roller has a hollow cavity. A plurality of gluing holes for gluing prepreg are opened on the outer peripheral wall of the hollow gluing guide roller. The gluing holes are all connected to the hollow cavity. The glue circulation device comprises: a glue storage tank; a first pump body connected to the glue storage tank and the hollow glue guide roller through a first pipe, for pressurizing the glue in the glue storage tank and injecting it into the hollow glue guide roller, wherein the glue inlet end of the first pipe is connected to the glue storage tank, and the glue outlet end is connected to the port of the hollow glue guide roller; A second pump body is connected to the glue storage tank and the prepreg tank through a second pipe, and circulates the glue in the prepreg tank to the glue storage tank, wherein the glue inlet of the second pipe is connected to the prepreg tank, and the glue outlet is connected to the glue storage tank.

2. The infiltration system for enhancing the wettability of prepreg according to claim 1, characterized in that: The main dipping device includes a main dipping tank, an upper tensioning roller, a lower tensioning roller and an extrusion roller. The upper tensioning roller is installed at the entrance of the main dipping tank, the lower tensioning roller is installed in the main dipping tank, and the extrusion roller is installed at the outlet of the main dipping tank. The prepreg after being impregnated in the prepreg tank passes through the upper tensioning roller to the lower tensioning roller and enters the main dipping tank. The prepreg after being impregnated in the main dipping tank is taken out by the extrusion roller.

3. The infiltration system for enhancing the wettability of prepreg according to claim 2, characterized in that: The viscosity of the glue in the pre-impregnation tank is lower than the viscosity of the glue in the main impregnation tank.

4. The infiltration system for enhancing the wettability of prepreg according to claim 1, characterized in that: The glue inlet end of the first pipe is connected to the bottom of the glue storage tank, and the glue inlet of the second pipe is connected to the bottom of the prepreg tank.

5. The infiltration system for enhancing the wettability of prepreg according to claim 1, characterized in that: The glue outlet hole is a circular hole with a diameter of 0.001-100 mm.

6. The infiltration system for enhancing the wettability of prepreg according to claim 1, characterized in that: The bump is a cone with a height of 0.001-1 mm.

7. A method for enhancing the wettability of a prepreg, characterized in that: The specific steps are as follows: a. The prepreg enters through the rolling tensioning guide roller, and the convex blocks on the outer peripheral surface of the rolling tensioning guide roller press the prepreg to make the prepreg loose in advance; Arrange multiple rolling and tensioning guide rollers along the feeding direction, so that the height of the protrusions of each rolling and tensioning guide roller increases step by step along the feeding direction, so that the prepreg gradually becomes loose; b. The loosened prepreg enters the prepreg tank through the hollow gluing guide roller. The first pump body pressurizes the glue in the liquid storage tank and injects it into the hollow cavity of the hollow gluing guide roller. The glue is then applied to the prepreg through the glue outlet hole. c. The prepreg after gluing enters the main impregnation device to continue impregnation.

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