KR101021489B1 - A backup board for manufacturing via holes of a printed circuit board - Google Patents

Abstract

PURPOSE: A backup board for manufacturing via holes of a printed circuit board is provided to use an adhesive made of a water soluble resin binder and water soluble resin lubricant, thereby preventing poisonous gas and dust. CONSTITUTION: A core(10) is one of an HDF board, an MDF board, or a plastic sheet. A backup board(1) compresses metallic thin film sheets(30) on which an water soluble adhesive(20) is applied on both sides of the core. The water soluble adhesive includes a water soluble resin binder 30~50 weight% and water soluble resin lubricant 50~70 weight%. The thickness of the core is 1~3 mm. The thickness of the adhesive is 5~100 micro meter. The thickness of a metallic thin film sheet is 30 ~ 150 micro meter.

Description

Backing board for via hole processing of printed circuit boards {A BACKUP BOARD FOR MANUFACTURING VIA HOLES OF A PRINTED CIRCUIT BOARD}

The present invention relates to a backing board for via hole processing of a printed circuit board, and more particularly, any one of a high density fiber (HDF), a medium density fiber (MDF) plywood, a plastic sheet as a core material, and on both sides of the core material Pressing the metal thin film sheet coated with a water-soluble adhesive to form a backup board, wherein the water-soluble adhesive comprises 30 to 50% by weight of the water-soluble resin binder and 50 to 70% by weight of the water-soluble resin lubricant, via-holes on the printed circuit board ( When drilling the via hole, it prevents the generation of toxic gas and dust and improves the accuracy of hole location by efficiently distributing frictional heat by the drill. The present invention relates to a backup board for via hole processing.

In general, a method of manufacturing a printed circuit board (PCB) forms a via hole penetrating through upper and lower surfaces of the printed circuit board and each circuit formed therein, and a conductive metal is formed on an inner wall of the via hole. Plating is performed to electrically connect the circuits.

In this case, a process of forming the via hole is called a drilling process, and as shown in FIG. 1, a plurality of printed circuit boards 2 are stacked on top of the backup board 1 and an entry board is placed on the uppermost printed circuit board 2. After stacking (3) finally, the via hole 5 is drilled using the drill 4, and the backup board 1 protects the working table and the drill 4 of the drilling machine and the printed circuit board 2 At the completion of the drilling of the via hole 5), the burr and the bending of the hole are prevented, thereby maintaining a constant quality of the printed circuit board.

Backup boards that play such a role are generally made of resin and wood products, and conventionally, melamine is used as a backup board in the middle density fiber (MDF) or high density fiber (HDF) compression plate. The resin impregnated or coated or made of phenol resin, but the melamine resin coated or impregnated melamine resin board on the fiber compression plate caused a large amount of dust during hole drilling (punching) was a factor of pollution In addition, there is a disadvantage that it is difficult to drill the hole at the exact position by the hole (needle) for the hole processing, and melamine board has a weakness that the plate is easily bent during hole processing due to its weakness, and it is difficult to precise hole processing. Since the heat dissipation is not very good, it was difficult to drill holes. In addition, when using the melamine resin board or phenolic resin board as a backup board, there is a problem in that it is not possible to recycle even during waste disposal, and in addition to the disadvantage of causing a problem to environmental pollution, additional costs must be paid for the prevention thereof.

As described above, the conventional backup board is formed by stacking a plurality of phenol resin sheets and phenol resin layers sequentially penetrated by phenol resin and compressing them for a long time using a heat press, or a melamine sheet impregnated with a melamine resin on a thin paper with MDF or HDF. It consists of a structure attached to the upper and lower surfaces of the made-up wood layer, and sometimes the aluminum foil (Al foil) attached to the upper and lower surfaces of the wood layer made of MDF or HDF, respectively.

However, the above-mentioned structure of the backup board is composed of phenol and melamine resins, which are mostly non-recyclable, so that a large amount of industrial waste is generated after use, which is not environmentally friendly. As a result, there is a problem that causes a defect of the printed circuit board. In addition, even when using renewable aluminum, there is also a problem that it is not easy to remove the aluminum foil from the wood layer for recycling.

Looking at the prior art for overcoming the above problems, Republic of Korea Utility Model Publication No. 20-0291968 (Notice date 2002.10.11), the hard thin on the upper and lower surface of the compressed paper layer 20 of about 1.5mm ± 0.1mm thick A back-up board for drilling a printed circuit board, characterized in that the thin film layers 30 are attached to each other, wherein the thin film layer 30 is a technique using a melamine sheet produced by depositing aluminum foil or thin paper in a melamine resin melt and drying it. Is disclosed.

However, the backup board according to the prior art has an effect that the amount of industrial waste is reduced and economical since the intermediate layer is made of recyclable paper, but it still has the problems of the prior art mentioned above.

In addition, the Republic of Korea Patent Publication No. 2002-0026237 (published 2002.04.06.) Is selected from high density fiber pressing plate (HDF), medium density fiber pressing plate (MDF), hard board, gypsum board, phenol board, Formax Any one of the cores (core material) 4 is formed on both sides of the core 1.6 to 2.5 mm thick and any one of ordinary metal or wood strong adhesives is provided through two or more composite adhesive layers 2 (2 '). To 20-20 micron thick aluminum or stainless steel sheet (1) (1 ') (foil), and then press high pressure using hot press used in the general panel or plywood manufacturing process. BACKGROUND OF THE INVENTION [0002] A backup board for processing a hole in a printed circuit board is known, which is configured by compression molding.

The prior art prevents warping during hole drilling, but when bonding aluminum or stainless steel thin plates to both sides of the core (core material), it is possible to secure the precision of hole drilling by bonding with a strong metal or wood strong adhesive. There is a problem that the back-up board after use can not easily peel off the metal thin plate from the core (core material) it is difficult to recycle it.

An object of the present invention is to reduce the drill friction during via hole processing of a printed circuit board because a water-soluble resin binder and a water-soluble resin lubricant are used as the adhesive for bonding the metal thin sheet of the backing board surface layer to the inner core material. By efficiently dissipating the generated frictional heat by the metal thin film and lubricant, it is possible to secure high-precision hole positioning accuracy even when drilling using a drill bit having a drill hole diameter of at least 0.05 mmΦ in a printed circuit board. It is to provide a backup board for via hole processing of a printed circuit board is extended, the life of the printed circuit board is suppressed the generation of drill hole burrs (burr) of the lower surface.

Another object of the present invention is to use a water-soluble resin binder and a water-soluble resin lubricant as an adhesive when manufacturing a backup board to prevent the generation of volatile gas and dust harmful to the human body when the via hole in the printed circuit board, Since the metal thin sheet and the core material is easily separated and recycled afterwards, it is to provide a backup board for via hole processing of a printed circuit board which is environmentally friendly and low in manufacturing cost.

In order to solve the above problems, the backing board for processing via holes of the printed circuit board of the present invention may be formed of any one of a high density fiber (HDF), a medium density fiber (MDF) plywood, and a plastic sheet. Pressing the metal thin film sheet coated with a water-soluble adhesive to form a backing board, the water-soluble adhesive is characterized in that it comprises 30 to 50% by weight of the water-soluble resin binder and 50 to 70% by weight of the water-soluble resin lubricant.

In addition, the present invention is characterized in that the thickness of the core material is 1 ~ 3mm, the water-soluble adhesive is 5 ~ 100㎛ thickness, the metal thin sheet is hard aluminum, ductile aluminum, nickel, copper or alloys thereof It is made of any one of the features, characterized in that the thickness is 30 ~ 150㎛.

The water-soluble resin binder contained in the water-soluble adhesive has a number average molecular weight of 10,000 or more, and contains any one or more of polyether ethylene monoether, polyoxyethylene ester, polyvinyl alcohol, and polyvinyl butadiene. The water-soluble resin lubricant contained in the adhesive has a number average molecular weight of 5,000 or less, and includes any one or more of esters of polyoxyethylene, sorbitan monoesters of polyoxyethylene, polyglycerine monoesters, and polyoxyethylene propylene block copolymers. Characterized in that.

The backup board for via hole processing of the printed circuit board of the present invention uses a water-soluble resin binder and a water-soluble resin lubricant to bond the metal thin film sheet of the surface layer and the core material of the inner layer, so that the release film between the drill bit and the adhesive for hole processing ( Release film) reduces drill friction and efficiently distributes the frictional heat generated by the metal thin film and lubricant, which extends the life of the drill bit and reduces the occurrence of burrs on the lower surface of the printed circuit board. As a result, the product is improved, and since the smear phenomenon of the lower side of the printed circuit board is minimized, the roughness of the perforated via hole is greatly improved.

In addition, the present invention uses a water-soluble resin binder and a water-soluble resin lubricant, which is an environmentally friendly material when manufacturing a backup board as an adhesive, when the via hole is punched in the printed circuit board does not generate volatile gas and dust harmful to the human body, it is contained in the adhesive Due to the releasing action by the water-soluble resin lubricant, the metal thin sheet and the core can be easily separated even after the disposal of the backup board after use, so that the material can be recycled, which is not only environmentally friendly but also excellent in reducing the manufacturing cost.

1 is a state diagram used in the general backup board.
2 is a longitudinal sectional view showing a backup board according to the present invention.

Hereinafter, the preferred embodiments of the present invention will be described in detail by dividing each configuration, which is intended to explain in detail enough to be able to easily carry out the invention by those skilled in the art to which the present invention belongs, This does not mean that the technical spirit and scope of the present invention is limited.

2 is a longitudinal cross-sectional view showing a backup board according to the present invention, which shows a structure in which a backup board is formed by pressing the metal thin film sheet 30 coated with a water-soluble adhesive 20 on both surfaces of the core material 10.

Via hole processing backup board of the printed circuit board according to the present invention is any one of the high-density fiber (HDF), medium-density fiber (MDF) plywood, plastic sheet as the core material 10, water-soluble on both sides of the core material (10) Compress the metal thin film sheet 30 coated with the adhesive 20 to form a backup board, wherein the water-soluble adhesive 20 comprises 30 to 50% by weight of the water-soluble resin binder and 50 to 70% by weight of the water-soluble resin lubricant It is characterized by.

The medium density fiber (MDF) plywood used as the core material in the present invention is made of a wood material (wood fiber) obtained by decomposing at high temperature by using a wood material as a main raw material of a density of 0.4 ~ 0.8g / ㎠ made by molding, hot pressing It is a wooden board product and is generally called high density fiber (HDF) plywood when the density is exceeded, and the fiber press plate has uniform fiber distribution and dense structure over the entire thickness, so that complex machining operations can be performed on both sides and sides. It can be performed smoothly without breaking the edges.

The plastic sheet is made of a polyvinyl chloride resin, a polystyrene resin, a polyethylene resin, a polypropylene resin, an acrylic resin, and a thermoplastic resin in which a copolymer of these is used alone or in a mixture thereof, compared to thermosetting resins such as phenol and melamine resin. Inexpensive and low specific gravity not only reduces manufacturing costs but also recycles the used backup board when discarded.

The core material 10 is preferably made of a thickness of 1 ~ 3mm, more preferably about 1.5 ~ 2mm to produce a thickness of about the best when considering the workability and heat dissipation by drilling.

In the present invention, the metal thin film sheet 30 is made of any one of hard aluminum, ductile aluminum, nickel, copper or alloys thereof, and because they are excellent in thermal conductivity, they are generated in bits during hole processing (punching). It dissipates heat in a short time and removes heat, so that the drill bit has less wear and continuous workability, and fine drill processing (hole drilling) of a printed circuit board which is gradually thin and thin according to the speed of technology development. ) It has the merit that a large number of holes can be finely and precisely processed at high speed rotation of the bit without generating overheating or warping.

The thickness of the metal thin film sheet 30 is advantageously used to select the thickness of about 30 ~ 150㎛ according to the type of the printed circuit board to exhibit the above advantages, if the thickness of the metal thin film sheet 30 is 150㎛ If it exceeds, the workability is reduced because the drill bit life is shortened and continuous machining is difficult.

In addition, the water-soluble adhesive 20 applied to one surface of the metal thin film sheet 30 does not use an organic solvent, and thus, there is no toxic gas generation in the human body as well as during operation. (20) is a mixture of 30 to 50% by weight of the water-soluble resin binder and 50 to 70% by weight of the water-soluble resin lubricant can exhibit a suitable viscosity, good workability, friction reduction effect, furthermore the initial adhesive strength and peelability after use All have been studied to exhibit the most desirable physical properties that can be met. In addition, the water-soluble resin binder is more preferably 20 to 40% solid content in terms of compatibility and dispersibility with the water-soluble resin lubricant.

In addition, the water-soluble adhesive 20 is preferably applied in a thickness of 5 ~ 100㎛ in terms of adhesiveness and thermal conductivity, which is why the release film (release film) between the drill bit and the adhesive during via hole processing of the printed circuit board ) To reduce drill friction and efficiently dissipate the generated friction heat by the metal thin film and the lubricant, and the metal thin film sheet 30 coated with the water-soluble adhesive 20 is used in a conventional panel or plywood manufacturing process. It is press-molded to the core material 10 using the press which becomes.

The water-soluble resin binder used in the water-soluble adhesive 20 is composed of the following resin components alone or mixed, specific types thereof are polyoxyethylene ester, polyoxyethylene urethane, polyoxyethylene propylene copolymer, polyoxyethylene cetyl Monoethers of polyoxyethylene such as ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene dodecyl ether, polyoxyethylene nonyl ether and polyoxyethylene octylphenyl ether; Monoethers of polyoxyethylene such as ethylene dodecyl ether, polyoxyethylene nonyl ether and polyoxyethylene octylphenyl ether; Polyoxyethylene esters such as polyoxyethylene monolaurate, polyoxyethylene monostearate and polyoxyethylene monooleate; Polyvinyl alcohol; Including at least one of polyvinyl butadiene is the most preferable type of binder in terms of adhesion and heat dissipation during drilling operations, the water-soluble resin binder is a thermoplastic resin using a polymer having a number average molecular weight of 10,000 or more This maintains proper adhesion to prevent slippage between layers that can be caused by prolonged drilling.

The water-soluble resin lubricant used in the water-soluble adhesive 20 is a low or medium molecular resin having a number average molecular weight of 5,000 or less, polyoxyethylene oleyl ether, polyoxyethylene dodecyl ether, polyoxyethylene nonylphenyl ether, poly Oxyethylene octylphenyl ether; Esters of polyoxyethylene, such as polyoxyethylene monolaurate, polyoxyethylene monostearate or polyoxyethylene monooleate; Sorbitan monoesters of polyoxyethylene, such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monooleate; Polyglycerol monoesters such as hexaglycerin monolaurate or decaglycerol monooleate; The water-soluble resin lubricant has a positive affinity structure, that is, a hydrophilic structure and a lipophilic structure at the same time to include at least one kind of polyoxyethylene propylene block copolymer, so that the hydrophilic surface is added to the synthetic resin of the lipophilic structure. Easily disperse structure improves the flowability of the binder and facilitates the dispersion, thereby preventing the shrinkage of the adhesive surface. In addition, it keeps the melting temperature of the adhesive low and facilitates the work, and also prevents the adhesion of the adhesive and the drill bit by the release action during the punching of via holes on the printed circuit board. Reduces friction coefficient and heat of friction by

For reference, the water-soluble adhesive 20 of the present invention may optionally include a small amount of additives such as a catalyst, an antifoaming agent, an emulsifier, a plasticizer, a dispersant, a filler, and the like without departing from the object of the present invention. This allows physical properties such as viscosity and flow rate to be modified. Since such additives are well known to those skilled in the art, detailed description thereof will be omitted.

Accordingly, the water-soluble adhesive 20 used in the present invention maintains a melting temperature of about 40 to 100 ° C., and efficiently absorbs and dissipates frictional heat of a drill bit during hole drilling of a printed circuit board by a drill. The invention can improve the hole quality of the bottom surface of the printed circuit board by the backup board to suppress the occurrence of burr, and even after using the backup board, the metal thin film sheet 30 is removed from the backup board by the action of the lubricant contained in the adhesive. It can be easily peeled off with little force. Due to this, the backup board of the present invention collects and regenerates all of the separated materials, thereby significantly reducing the industrial waste compared to the conventional, so that the cost is remarkably saved and it is very friendly to the environment.

As described above, the present invention has been completed through numerous experiments. Hereinafter, the present invention will be described through preferred embodiments to be easily understood and implemented by those skilled in the art.

≪ Example 1 >

A 2mm thick MDF plywood was used as the core material, and two aluminum sheets having a thickness of 80 µm were prepared, and 40 wt% of a water-soluble resin binder having a solid content of 30% and a water-soluble resin lubricant 60 on one surface of each aluminum sheet. A water-soluble adhesive formed by mixing the weight% was applied to a thickness of 50㎛, and then the backing board was manufactured by compressing the aluminum sheet coated with the adhesive on both sides of the core material.

<Example 2>

A backup board was manufactured in the same manner as in Example 1, except that a polyvinyl chloride resin (PVC) sheet having a thickness of 2 mm was used as the core material.

Comparative Example 1

A backup board made of a phenolic resin sheet, which is a thermosetting resin having a thickness of 2 mm, was prepared.

Comparative Example 2

A backup board was prepared in the same manner as in Example 1 except that the water-soluble resin lubricant was not used as the water-soluble resin adhesive.

Evaluation result after use

As a result of measuring the quality of the backup boards manufactured in Examples 1 and 2 and Comparative Examples 1 and 2, respectively, the backup boards manufactured by Examples 1 and 2 are lighter and the dimensional change of the adhesive surface due to the shrinkage of the adhesive Almost no, it was confirmed that the workability, friction heat dissipation, burr (burr) prevention, etc. are all superior to the backup board according to Comparative Example 1 or Comparative Example 2.

In addition, the roughness of the via holes perforated on the printed circuit board using the backup boards manufactured by Examples 1 and 2 was greatly improved, and the backup board products were excellent in durability and after use. When discarding, the sheet metal sheet can be easily separated and separated from the core material, which is an environmentally friendly product capable of recycling all the waste materials. Thus, the cost of manufacturing and using the material can be reduced by about 30%.

Therefore, the backup board of the present invention, as well as the through-hole drilling of the printed circuit board, as well as making holes in the laminate or plastic board, after placing the drill lubricant sheet on the upper surface of the laminate or plastic board drill holes through the drill operation It can be used as a lubricant sheet for drills to be made, and also various substitutions, modifications and modifications can be made within the scope without departing from the technical idea of the present invention, such as hole drilling of plastic boards requiring precise drilling. Can be applied as

1: Backup board 2: Printed circuit board
3: entry board 4: drill
5: via hole 10: heartwood
20: water soluble adhesive 30: metal thin sheet

Claims (7)

The high-density fiber (HDF) or the medium-density fiber (MDF) plywood, a plastic sheet of any one of the core material 10, the metal thin film sheet 30 is coated by applying a water-soluble adhesive 20 on both sides of the core material Forming a backup board (1), wherein the water-soluble adhesive 20, 30 to 50% by weight of the water-soluble resin binder and 50 to 70% by weight of the water-soluble resin lubricant, via-hole backing board for processing the printed circuit board. The method of claim 1,
The core material 10 is a back board for via hole processing of a printed circuit board, characterized in that the thickness of 1 ~ 3㎜. The method of claim 1,
The plastic sheet used as the core material 10 includes a polyvinyl chloride resin, a polystyrene resin, a polyethylene resin, a polypropylene resin, an acrylic resin, and a via hole of a printed circuit board comprising a thermoplastic resin obtained by mixing a single or a mixture thereof. Machining backup board. The method of claim 1,
The water-soluble adhesive 20 is a backup board for via hole processing of a printed circuit board, characterized in that the thickness of 5 ~ 100㎛. The method of claim 1,
The metal thin film sheet 30 is made of any one of hard aluminum, soft aluminum, nickel, copper, or alloys thereof, and has a thickness of 30 to 150 µm. The method according to any one of claims 1 to 5,
The water-soluble resin binder contained in the water-soluble adhesive 20 has a number average molecular weight of 10,000 or more, and comprises any one or more of polyether ethylene monoether, polyoxyethylene ester, polyvinyl alcohol, and polyvinyl butadiene. Back-up board for via hole processing of printed circuit board. The method according to any one of claims 1 to 5,
The water-soluble resin lubricant contained in the water-soluble adhesive 20 has a number average molecular weight of 5,000 or less, and any one of an ester of polyoxyethylene, a sorbitan monoester of polyoxyethylene, a polyglycerol monoester, and a polyoxyethylene propylene block copolymer A backup board for via hole processing of a printed circuit board comprising at least one species.

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