CN106985396B

CN106985396B - Method for controlling glue flow of copper-clad plate

Info

Publication number: CN106985396B
Application number: CN201710024846.2A
Authority: CN
Inventors: 王文潮
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-01-13
Filing date: 2017-01-13
Publication date: 2020-04-14
Anticipated expiration: 2037-01-13
Also published as: CN106985396A

Abstract

The invention discloses a method for controlling the flowing glue of a copper-clad plate, which is characterized in that each bonding sheet is subjected to edge covering treatment and then is pressed in the manufacturing process of the copper-clad plate, and the original preparation process of the copper-clad plate is improved, so that the flowing glue of mixed resin glue liquid flowing out of the outer edge of the bonding sheet in the heating and pressurizing process of the bonding sheet and a series of negative effects caused by the flowing glue can be effectively avoided, and the method can be applied to the manufacturing fields of the copper-clad plate, an insulating plate, a multilayer circuit board and the like.

Description

Method for controlling glue flow of copper-clad plate

Technical Field

The invention belongs to the technical field of copper-clad plate preparation, relates to a novel method for preparing a copper-clad plate, and particularly relates to a method for controlling the glue flowing of the copper-clad plate.

Background

The reinforcing material soaked with the glue solution of the mixed resin is baked and dried to partially improve the curing degree of the resin and become solid bonding sheets, the bonding sheets are laminated together after being sliced, copper foils or release films are covered on two sides of the bonding sheets, and the bonding sheets are heated and pressed in vacuum to prepare copper-clad laminates, which are called copper-clad plates for short (called insulating plates without copper on two sides), and the copper-clad laminates are mainly applied to manufacturing Printed Circuit Boards (PCBs). And pressing the printed circuit boards into a whole by using the bonding sheets to obtain the multilayer circuit board.

In the process of heating and pressing, the resin in the bonding sheet is re-melted along with the increase of the temperature because the resin has low crosslinking degree. In the vacuum laminating machine, under the combined action of vacuum and pressure, the molten glue liquid extrudes air and occupies the inner space, and simultaneously the molten glue liquid flows out of the outer edge of the bonding sheet. As the lamination process proceeds, the temperature continues to rise and the resin continues to undergo a crosslinking reaction and eventually cure. The phenomenon that the mixed resin glue solution flows out of the outer edge of the bonding sheet is called glue flowing.

The running glue causes several series of negative effects: the edge thickness of the copper-clad plate is lower than the middle thickness due to glue flowing, so that the subsequent automatic machining is adversely affected, and the electrical and electronic properties of the final product are also adversely affected; the glue flowing can cause glue shortage at the inner edge of a copper-clad plate base material, the glue shortage edge of the base material needs to be cut off in the subsequent edge cutting process, and the edge cutting is called as edge cutting, so that the material waste is caused; the flowing glue can cause the edge adhesion of the copper-clad plate after pressing. In order to avoid adhesion, the bonding sheet needs to be covered by copper foil with the ultra-width of 15-20 mm, and the copper foil is cut off in the edge cutting process, so that the copper foil is wasted.

The cut copper-clad plate edge strips usually use strong acid to recover copper foil on the edge strips, so that the environment is polluted to a certain degree. The remaining substrate edge strips are industrial solid waste, most of which are bromine-containing hazardous industrial solid waste.

Disclosure of Invention

The invention aims to provide a method for controlling the glue flowing of a copper-clad plate, which aims to solve the problem of glue flowing when the copper-clad plate, an insulating plate and a multilayer circuit board are laminated.

In order to achieve the purpose, the method for controlling the glue flowing of the copper-clad plate comprises the steps of performing edge covering treatment on each bonding sheet and then performing pressing in the manufacturing process of the copper-clad plate.

In the above technical solution, the method of hemming treatment is as follows: selecting a material capable of resisting the temperature of the copper-clad plate during pressing as a wrapping material, cutting the material into strips to obtain wrapping strips, wrapping each edge of the bonding sheet by using the wrapping strips, and heating and pressing until the edges of the bonding sheet are completely wrapped.

Further, the edge wrapping band may be preprocessed as follows:

selecting a resin curing accelerator capable of rapidly curing the resin according to a resin system of the bonding sheet; selecting a solvent capable of dissolving the resin curing accelerator; dissolving a resin curing accelerator in the solvent to obtain a solution; soaking the edge-wrapping band in the above solution, taking out, drying, and making into medicated edge-wrapping band.

The selection principle of the resin curing accelerator is as follows: the curing speed of the resin is used as a selection index, and the higher the curing speed, the better the curing speed. The method of the invention often selects the medicament which can accelerate the resin solidification at the highest speed around the remelting temperature of the bonding sheet resin, and does not generally make requirements on the performance of the solidified resin. Taking the most widely used epoxy resin in the copper-clad plate industry as an example, the best resin curing accelerator is dimethyl imidazole.

The selection principle of the edge covering material is as follows: can absorb the resin curing accelerator to a certain degree and can bear the temperature at least in the initial stage of the copper-clad plate lamination. For epoxy resin bonding sheets and dimethyl imidazole, paper fiber material is a suitable edge covering material.

The selection principle of the solvent for dissolving the resin curing accelerator is as follows: can dissolve the resin curing accelerator, is preferably volatile, has affinity with the edge covering material, and is non-toxic or slightly toxic. For dimethylimidazole, acetone is a suitable solvent.

The production of the edge wrapping band can preferably meet the following conditions:

1. the radial tensile strength of the edge covering belt is ensured not to be broken when the edge is covered;

2. the thickness of the edge wrapping belt is considered to basically keep the whole bonding sheet flat after the edge wrapping belt is pressed on the edge of the bonding sheet;

3. the width of the edge covering belt is preferably small in principle, but the glue flow can be completely prevented in the copper-clad plate laminating process. At the same time should consider

The overlapping error is used for avoiding the glue flowing caused by the dislocation of the edge wrapping belt;

4. the density of the edge wrapping band is considered to be that when the edge wrapping band is thermally pressed on the edge of the bonding sheet, the melted glue solution can penetrate into the inner hole of the edge wrapping band

The gaps, rather than being extruded out of the taping, cause the bonding sheet to be overall uneven.

When the binding tape is heated and pressed, the operating temperature and speed can be controlled to meet the requirement of the integral smoothness of the binding tape and ensure that the binding tape and the binding tape are bonded.

The invention has the beneficial effects that: the method of the invention is used for wrapping the bonding sheet, so that the copper-clad plate, the insulating plate and the multilayer circuit board do not flow glue when being laminated, and thus, the invention has a plurality of beneficial effects:

1. the inner edge of the base material is free from glue shortage. In the subsequent edge cutting process, the edge with the width of about 2mm needs to be cut, the edge is cut inwards for 1mm more for quality guarantee, and the product quality can be guaranteed by actually cutting the edge of the base material for 3 mm.

2. The edges are not sticky. The copper foil can effectively avoid edge adhesion as long as the bonding sheet is covered by the copper foil with the super width of 1-2 mm.

3. According to the above two

items

1 and 2, since the width of the edge is reduced and the area covered with the copper foil is reduced, the raw material can be saved.

4. The edge thickness and the middle thickness of the finished plate are good in consistency, the product quality is improved, and the product selling price can be increased to a certain extent.

5. Because the width of the cut edge is reduced, the use amount of strong acid for recovering the copper foil and the generation amount of industrial solid wastes are reduced, and certain environmental protection benefits are realized.

For a better understanding of the nature and technical aspects of the present invention, reference should be made to the following detailed description of the invention, taken in conjunction with the accompanying drawings, which are provided for purposes of illustration and description and are not intended to limit the invention.

Drawings

FIG. 1 is a schematic flow diagram of an improved copper-clad plate original process; the dotted line part in the figure is the improvement of the original process of the copper-clad plate;

FIG. 2 is a schematic cross-sectional view of an adhesive sheet hem;

FIG. 3 is a schematic plan view of the bonding sheet hem;

FIG. 4 is a mark point of the copper-clad plate for measuring thickness in the embodiment of the invention.

Detailed Description

To further illustrate the technical means and effects of the present invention, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.

Taking the most common epoxy resin system in the copper-clad plate industry as an example, the implementation of the content of the invention comprises the following steps:

step 1, aiming at the epoxy resin bonding sheet, the optimal resin curing accelerator is dimethyl imidazole.

And 2, selecting a paper fiber material as a wrapping material according to the epoxy resin bonding sheet and the dimethyl imidazole. In the experiment, a commercially available roll-mounted napkin was selected as the edge-covering material.

And 3, selecting acetone as a solvent for the dimethyl imidazole.

And 4, dissolving the dimethyl imidazole in acetone at room temperature to prepare a dimethyl imidazole acetone saturated solution for later use.

Step 5, manufacturing a binding belt by using a binding material: the commercially available scroll-mounted napkin in step 2 is 3 layers, 1 of which is taken and has a thickness of about 0.04 mm. Cutting into paper strips with the length of 400mm and the width of 20mm, namely the non-medicine-packaging side bands for later use.

And 6, dipping the drug-free edge wrapping tape in the step 5 in the dimethyl imidazole acetone saturated solution in the step 3, taking out, slightly squeezing, volatilizing, and preparing the drug-dipped edge wrapping tape.

Step 7, cutting the bonding sheet: the large epoxy resin bonding sheet is cut into 300mm by 300mm, and is called as an unbelted bonding sheet. 12 sheets were prepared.

Step 8, edge covering:

and 8.1, carrying out hot-press bonding on the edge wrapping tape to the bonding sheet by using a commercially available thermoplastic sealing machine, electrifying, adjusting the temperature to a medium-low level, and heating to a constant temperature for later use.

And 8.2, wrapping two sides of one edge of the non-wrapped bonding sheet in the step 7 by using the non-wrapped edge band in the step 5, pressing the wrapped edge band by using a thermoplastic sealing machine in the step 8.1, controlling the pressing width to be 2mm, and cutting off the non-pressed redundant part of the paper tape by using a paper cutter. Repeating the steps to complete the edge covering of four edges of the bonding sheet, and thus obtaining the bonding sheet without the edge of the medicine bag. 4 pieces of bonding sheets without edge of medicine bag are prepared.

And 8.3, preparing 4 pieces of medicine soaking edge binding bonding sheets by using the medicine soaking edge binding belt in the step 6 according to the method in the step 8.2.

Step 9, overlapping:

and 9.1, taking 4 binding sheets without edges in the step 7, covering a 0.5OZ copper foil on the lower surface of the binding sheets and a release film on the upper surface of the binding sheets to finish the overlapping and the standby.

And 9.2, taking 4 non-edge-packaged bonding sheets obtained in the step 8.2, covering a 0.5OZ copper foil on the lower surface of each bonding sheet and covering a release film on the upper surface of each bonding sheet to finish the overlapping and the standby.

And 9.3, taking 4 medicine soaking and edge covering bonding sheets in the step 8.3, covering a 0.5OZ copper foil on the lower surface of the medicine soaking and edge covering bonding sheets and covering a release film on the upper surface of the medicine soaking and edge covering bonding sheets to complete the overlapping and the standby.

Step 10, pressing:

and step 10.1, the machine for pressing is a small-sized vacuum laminating machine, power is supplied, pressing parameters are set, and preheating is completed for later use.

And step 10.2, pressing the overlapped articles in the step 9.1, the step 9.2 and the step 9.3 into a laminating operation program, overlapping the articles together, putting the articles into a vacuum laminating machine, and starting a laminating program to complete lamination.

And 11, taking out the pressed article in the step 10.2, and tearing off the release film to obtain 3 single-sided copper-clad plates. Wherein the finished product corresponding to the article in the step 9.1 is called an un-edge-coated copper-clad plate, the finished product corresponding to the article in the step 9.2 is called an un-edge-coated copper-clad plate, and the finished product corresponding to the article in the step 9.3 is called a medicine-impregnated edge-coated copper-clad plate.

Step 12, respectively measuring the glue flowing width and the glue lacking width of the copper-clad plate without edge covering, the copper-clad plate without edge covering and the copper-clad plate with edge covering after medicine soaking:

table 1: the width value (mm) of the glue flowing and the glue lacking of 3 kinds of copper-clad plates prepared by the experiment

	Non-edge-covered copper-clad plate	Copper-clad plate without medicine bag edge	Medicine-dipping edge-covering copper-clad plate
				Gummosis on outer edge of base material	8～20	1～2	0
Inner edge glue shortage of base material	2～4	0～1	0

Table 1 shows that the outer edge of the base material of the copper-clad plate without edge coating has obvious gummosis, and the inner edge of the base material has lacked gum due to the gummosis problem. The outer edge of the base material of the non-medicine-bag-edge copper-clad plate has little gumming, which indicates that the non-medicine-bag edge band has obvious mechanical barrier effect on the outward extrusion of the gum solution, but the coating material has pores and has slight gumming. The non-glue flowing of the edge of the medicine-dipping edge-covering copper-clad plate shows that in the initial stage of a pressing procedure, namely the initial stage of the bonding sheet being heated and melted, the resin curing accelerator in the medicine-dipping edge-covering belt enables the resin at the edge of the bonding sheet to be cured quickly, the edge is completely sealed by matching with the mechanical blocking effect of the edge-covering belt, glue liquid is enabled not to flow outwards completely, and meanwhile, the inner edge of a base material is enabled not to be in glue shortage.

Step 13, cutting the non-edge-covered copper-clad plate and the medicine-dipping edge-covered copper-clad plate in the step 12 along a diagonal line as shown in fig. 4, marking, and measuring the thickness:

table 2: non-covered copper clad laminate and medicine-dipped covered copper clad laminate multipoint thickness value (mm)

Table 2 shows that the thickness of the corner points is obviously smaller than that of the middle point due to the flowing of the glue of the copper-clad plate without edge covering, the range difference (the difference between the maximum value and the minimum value) reaches 0.19mm, and the ratio (range difference/maximum value) is 23.75 percent. The corner thickness and the middle thickness of the medicine-dipped edge-covered copper-clad plate are good in consistency, the range is 0.05 percent, and the proportion is 6.17 percent

In conclusion, the method provided by the invention has the advantages that the adhesive sheet is wrapped by the medicine-dipping edge wrapping belt, so that the edge glue flowing during the lamination of the copper-clad plate, the insulating plate and the multilayer circuit board can be avoided, the width of the cut edge of the plate can be effectively reduced, the raw materials are saved, the thickness consistency of the copper-clad plate, the insulating plate and the multilayer circuit board is better, and meanwhile, certain environmental protection benefits are achieved.

As described above, it will be apparent to those skilled in the art that other various changes and modifications may be made based on the technical solution and concept of the present invention, and all such changes and modifications are intended to fall within the scope of the appended claims.

Claims

1. A method for controlling the glue flowing of a copper-clad plate is characterized in that in the manufacturing process of the copper-clad plate, each bonding sheet is subjected to edge covering treatment and then is subjected to overlapping and pressing;

the edge covering method comprises the following steps: selecting a material capable of resisting the temperature of a copper-clad plate during lamination as a binding material to obtain a strip-shaped binding band, and pretreating the binding band as follows: selecting a resin curing accelerator capable of rapidly curing the resin according to a resin system of the bonding sheet; selecting a solvent capable of dissolving the resin curing accelerator; dissolving a resin curing accelerator in the solvent to obtain a solution; soaking the edge-wrapping band in the above solution, taking out, drying, and making into drug-soaked edge-wrapping band;

and (3) wrapping each edge of the bonding sheet by using a medicine soaking wrapping band, heating and laminating until the edge of the bonding sheet is completely wrapped, wherein the laminating width is ensured to be as small as possible while the glue flow can be completely prevented in the laminating process of the copper-clad plate.