JP2000127094A - Subboard for drilling work and reproducing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recycle a subboard by heating and hardening a mixed powder material for molding including a thermosetting binder resin powder material of specified mesh at a specified ratio and including a filled powder material and molding the mixed powder material into a planar shape. SOLUTION: As a filled powder, cutting powder, polishing powder and drilling chip powder generated at the time of working a thermosetting resin laminated plate, a pre-preg sheet and a wood material plate as they are can be utilized. Defectives and end materials generated at the time of working and small pieces generated at the time of punching drilling are obtained as crushed powder by being crushed up to a prescribed grain diameter. Also a used wear plate and a subboard are crushed up to the prescribed grain diameter in the same way and can be utilized as crushed powder. It is necessary that thermosetting binder resin powder is a powder material under 50-mesh screen and is contents of 5 wt.% or more. When the powder material is on 50-mesh screen or less than 5 wt.%, the filled powder can not be sufficiently bound and an excellent molded plate can not be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting resin laminate, a prepreg sheet, a discarding plate for punching and a backing plate formed by molding powder obtained from a wood base plate.

[0002]

2. Description of the Related Art At a processing site of a printed wiring board using a phenolic resin laminated board or an epoxy resin laminated board, and a wooden material board such as a timber or a particle board, a process of cutting the board to a predetermined size is performed by cutting. A large amount of cutting powder, polishing powder, and drilling powder is generated in the step of polishing the surface and end face of a damaged plate, and in the step of drilling a plate. In addition, a large amount of defective plates and scraps are generated during processing, and they are crushed and discarded as crushed powder.

[0003] In the drilling process for forming a sour hole and the drilling of a wooden material plate in the manufacture of printed wiring boards, the movement of the drill is stabilized by arranging a backing plate and a discard plate on the front and back of the workpiece. This suppresses the generation of burrs from the workpiece. Usually, since the surface condition of the discard plate / pattern greatly affects drilling, the discard plate / pattern once used in the drilling process is discarded as it is.

[0004]

However, due to the recent tightening of disposal sites, cutting powder / abrasive powder / drill holes generated in large quantities at the processing sites for printed wiring boards and wood material boards as described above. Disposal of powder / crushed powder and used discarded / plated plates is regarded as more problematic.
Abrasive powder / Drill hole powder / crushed powder and used discarded plate /
Since the backing plate has hardly deteriorated in terms of material, recycling of the material has been desired from the viewpoint of resource saving.

[0005] In the present invention, the cutting powder generated in the processing step /
Abrasive powder / Drill hole powder / crushed powder and used discarded plate /
A first object is to provide a discard plate or a caul plate used for drilling for the purpose of recycling the caul plate, and further to provide a method of regenerating a used discard plate / caul plate. The purpose was 2.

[0006]

According to the present invention, a thermosetting resin resin powder containing at least 5 wt% of a thermosetting binder resin powder under a 50-mesh screen is further impregnated into a thermosetting resin laminate or a base material. Using a mixed powder for molding containing a cutting powder, an abrasive powder, a drilling powder, or a filling powder consisting of crushed powder obtained from at least one selected from a prepreg sheet or a wood material board. The first object has been achieved by a discarding plate for drilling, which has a powder molded layer formed by heating and curing a mixed powder for use to form a plate.

Further, according to the present invention, a used discarding plate having one or more holes on its surface contains 5 wt% or more of a thermosetting binder resin powder under a 50-mesh sieve, and further contains a thermosetting resin. Resin laminate, or a prepreg sheet impregnated with a thermosetting resin varnish on a base material, or a cutting powder, an abrasive powder, a drilling powder, or a crushed powder obtained from at least one selected from a wood material board. A method for reclaiming a discarded plate for drilling, comprising a step of filling at least a part of the hole using a mixed powder for molding including a filling powder, and a step of heating and curing the mixed powder for molding. Has achieved the second object.

Further, in the present invention, the used discarding plate having one or more holes on its surface contains at least 5 wt% of thermosetting binder resin powder under a 50-mesh sieve, and further comprises thermosetting. Resin laminate, or a prepreg sheet impregnated with a thermosetting resin varnish on a base material, or a cutting powder, an abrasive powder, a drilling powder, or a crushed powder obtained from at least one selected from a wood material board. A step of filling at least a part of the holes using a mixed powder for molding including a filling powder, a step of stacking a plurality of the used drilling discarded plates in which the holes are filled with the mixed powder for molding, And a method for regenerating a perforated discarding plate, comprising heat curing the mixed powder for molding and integrating a plurality of the used perforated discarding plates. To achieve the serial second object of the present invention.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The discarding plate for drilling in the present invention includes both a patch plate disposed on the front side of an object to be hit by a drill in drilling and a disposal plate disposed on the back side of the object.

FIG. 1 is a sectional view showing the construction of the first discarding plate for drilling according to the present invention. This is a configuration in which a powder molded layer 1 obtained by mixing a thermosetting binder resin powder and a filling powder into a plate-like mixed powder obtained by molding is used as a discard plate for drilling.

The filler powder used in the present invention may be a thermosetting resin laminate, a prepreg sheet in which a base material is impregnated with a thermosetting resin varnish, or a cutting powder, an abrasive powder, or a drilled hole obtained from a wooden material. Processing powder or crushed powder is used. As thermosetting resin laminates, paper such as kraft paper, linter paper, mixed paper, antimony paper,
A prepreg sheet made by impregnating a thermosetting resin varnish such as phenolic resin, melamine resin, epoxy resin, unsaturated polyester, or polyurethane with a base material using a woven or nonwoven fabric of cotton, glass, polyester, aramid, etc. What is laminated and heat-cured is used. Also,
A cutting powder, an abrasive powder, a drilling powder, or a crushed powder obtained from an uncured prepreg sheet in which a thermosetting resin varnish is impregnated in a base material is also used. Further, as a wood-based material board, a timber, a laminated wood, a plywood, a particle board, a fiber board, or the like is used, and is a composite material of a cellulose fiber body and lignin which is a phenolic compound. In the present invention, a thermosetting resin laminate used as a filling powder, or a prepreg sheet impregnated with a thermosetting resin varnish on a substrate, or a cutting powder obtained from a wood material, an abrasive powder, a drilling powder, or Crushed powder,
We focused on a composite material of a fibrous material and a thermosetting resin material. In other words, when the filling powder is molded with the thermosetting binder resin powder, a high binder effect is obtained because the thermosetting resin material in the filling powder and the thermosetting resin binder added at the time of molding are easily compatible. On the other hand, on the other hand, there is an effect that the strength of the discarded plate formed by the fibrous material in the filling powder is improved.

[0012] The size of the filled powder in the present invention is not particularly limited, but is preferably about 20 mesh below the sieve. If the particle size is larger than 20 mesh sieve, unevenness of the material of the formed plate is conspicuous with respect to the diameter of the drill, and the drilling is not stable, and the wear of the drill is easily promoted.

[0013] The amount of the filler powder added in the present invention is not particularly limited, but if the amount of the filler powder is less than 50 wt%, the obtained discarded plate becomes brittle and easily breaks during drilling. It is preferably at least 50 wt%.

As the filling powder in the present invention, cutting powder, polishing powder, drilling powder and the like generated during the processing of a thermosetting resin laminate, a prepreg sheet, and a wooden base plate can be used as they are. Defective products and scraps generated during processing and small pieces generated during punching and punching are obtained as crushed powder by crushing to a predetermined particle size. In addition, a used patch plate or discarded plate can be similarly crushed to a predetermined particle size and used as crushed powder. Further, the present invention can be applied to a printed wiring board generated from a used electric appliance or the like. A laminate obtained by removing solder, copper foil, electronic components, and the like from the printed wiring board is subjected to crushing treatment to obtain a filled powder.

In the present invention, in particular, when the filling powder contains non-ferrous metal powder, the heat conductivity of the obtained discarded plate is improved, so that the cutting heat generated during drilling can be effectively released. It is preferable. As the non-ferrous metal powder, a metal powder having a low hardness such as copper or aluminum is used to suppress abrasion of the drill by the metal powder. In particular, when a through hole is formed in a printed circuit board by drilling, the resin material constituting the board is melted by the cutting heat and adheres to the surface layer of the through hole, causing poor plating adhesion. A configuration with increased thermal conductivity is effective. In order to obtain the heat radiation effect, the content of the metal powder in the filling powder is 10
Preferably, the ratio is about 50 wt%. 50w
Care must be taken when the content of the metal powder is as high as about t% or more, since the wear of the drill by the metal powder becomes a problem.
In the case of non-ferrous metal powder, in particular, cutting powder, polishing powder, drilling powder, or crushed powder of copper-clad laminate generated during the manufacture of printed circuit boards, copper powder obtained from copper-clad laminate, drilling When an aluminum sheet is used as the backing plate, a filled powder containing aluminum powder can be obtained as it is. Further, a metal dispersion paste in which metal powder such as copper powder is dispersed in a paste-like thermosetting resin is also used. It can be used by mixing the metal dispersion paste as it is in the filling powder, or by mixing the powder obtained by hardening and then crushing the metal dispersion paste into the filling powder.
Also, non-ferrous metal shredder dust generated as waste can be applied.

As the thermosetting binder resin powder in the present invention, an uncured powder of a thermosetting resin such as a phenol resin, a melamine resin, an epoxy resin, and a urea resin is used. Used.

The thermosetting binder resin powder in the present invention needs to be a powder under a 50-mesh sieve and has a content of 5 wt% or more. If the particle size is over a 50-mesh sieve, or if the content is less than 5 wt%, the filled powder cannot be sufficiently bound and a good molded plate cannot be obtained. In particular, it is preferable that the thermosetting binder resin powder be reduced to below about 100 mesh sieve because the number of particles per unit addition increases, so that a small amount of addition can favorably bind the filler powder, which is preferable.

In the present invention, in particular, a cutting powder, a polishing powder, a drilling powder, or a crushed powder of a phenolic resin laminate is used as a filling powder, and a phenolic resin is used as a thermosetting binder resin powder. Since the methylol groups remaining unreacted in the phenolic resin laminate partially react with the phenolic resin as the thermosetting binder resin powder, even if a small amount of the thermosetting binder resin powder is added, it is filled. It is preferable because the powder can be bound.

As a method for producing a discarded plate for drilling according to the present invention, a thermosetting binder resin powder and a filling powder are preliminarily mixed to prepare a mixed powder for molding, followed by injection molding, extrusion molding, and the like. General molding methods such as compression molding and compression molding are possible. However, in the injection molding method and the extrusion molding method, especially when the addition amount of the filling powder is about 50 wt% or more, the flowability at the time of molding deteriorates and good molding cannot be performed. It is preferable to use a compression molding method.

In the present invention, in particular, as shown in FIG. 2, the powder molded layer 1a has a relatively low density of 1.1 g / cc or less, and a high density layer of 1.3 g / cc or more on its surface. 2 are desirably stacked. When a boring process is performed by arranging a discarding plate or a backing plate so that the high-density layer 2 is in contact with the object to be drilled, the surface density of the high-density layer 2 is high, so that burr generation from the object is suppressed. Further, the wear of the drill can be suppressed by the soft low-density powder molding layer 1a. Such a discarded plate having layers with different densities can be easily produced by controlling the amount and the molding pressure to be charged into a molding die using a common mixed powder for molding. For example, if the compression molding method is used, the high-density layer 2 is formed by charging the mixed powder for molding into a molding die and applying a high pressure, and the mixed powder for molding is further charged on the surface thereof and molded at low pressure. A low-density powder molding layer 1a can be laminated.

Further, the density of the prepreg sheet can also be increased by heating and curing a prepreg sheet in which a base material is impregnated with a thermosetting resin varnish, or a cutting powder, an abrasive powder, a drilling powder or a crushed powder obtained from the prepreg sheet. 3g /
A high-density layer 2 of cc or more is obtained. Since the resin can be cured and molded with a thermosetting resin varnish without adding a new binder resin, the weight ratio of the base material can be increased and a high-density layer can be easily obtained. Kraft paper, cotton cloth, glass cloth, or the like is used as the base material, and phenol resin varnish, epoxy resin varnish, or the like is used as the thermosetting resin varnish.
In order to obtain a high-density layer, the impregnation amount of the thermosetting resin varnish is preferably in the range of about 30 to 60 wt%. For example, a mixed powder for molding is sandwiched between prepreg sheets in a molding die, and compression molding is performed at a low pressure, so that a low-density powder molding layer 1a is sandwiched between high-density layers 2 as shown in FIG. A discarded plate is obtained and both sides of the discarded plate can be used for drilling.

In the present invention, it is particularly preferable that the powder molding layer contains fine particles having a primary particle diameter of 1 μm or less.
Due to this, the fine particles adhere to the surface of the thermosetting binder resin powder or the filling powder, suppressing the agglomeration of the powders, improving the fluidity of the powders, and producing the mixed powder for molding. The mutual mixing / dispersion state of the filling powder and the thermosetting binder resin powder is improved, and then a good powder molding layer is obtained by heat curing. In addition, since the obtained mixed powder for molding has high fluidity, the mixed powder for molding can be easily and uniformly charged into a molding die particularly when compression molding is performed. Since the fine particles need to be sufficiently smaller than the thermosetting binder resin powder or the filled powder, fine particles having a primary particle diameter of 1 μm or less are used. In particular, it is preferable to use fine particles having a primary particle diameter of 0.1 μm or less, because the secondary particle diameter is sufficiently small even when the primary particles aggregate to form secondary particles. It is preferable to use silicon oxide, aluminum oxide, titanium oxide, or carbon black as the material used for the fine particles, since the material easily adheres to the thermosetting binder resin or the filling powder and has the effect of improving the fluidity. The optimum addition amount of the fine particles varies depending on the size of the particles of the thermosetting binder resin powder or the filling powder.
This is performed in a range of about 0 wt%. In particular, when the addition amount of inorganic fine particles such as silicon oxide, aluminum oxide, and titanium oxide is more than 10 wt%, the wear of the drill due to the inorganic fine particles may be accelerated, and caution is required.

FIG. 4 is a conceptual diagram of a method for regenerating a discarded plate for drilling according to the present invention. The hole 4 is filled with a molding mixed powder 5 containing a thermosetting binder resin powder and a filling powder on the used discard plate 3 having the hole 4 on the surface (step A). Thereafter, the powder mixture layer 5 is heated and cured to form the powder molding layer 1 and the used discarded plate is regenerated (step B). According to the recycling method of the present invention, a hole portion of a used discard plate can be efficiently filled, and a discard plate having a flat surface can be easily obtained. In particular, in the present configuration, a sufficient strength is ensured by the used discarded plate, and there is a feature that a good discarded plate for drilling can be obtained even if the powder molding layer is small and the thickness is small. Although FIG. 4 shows the used discard plate 3 having a hole only on one side, a used discard plate having holes on both sides can be applied in the present invention.

FIG. 5 shows a conceptual diagram of a second method for regenerating a discarded plate for drilling according to the present invention. A molding mixed powder 5 containing a thermosetting binder resin powder and a filling powder is placed on a used discard plate 3 having a hole 4 on its surface.
To fill hole 4 (step A). Thereafter, a plurality of the used discarded plates 3 obtained in the step A are stacked (step C). afterwards,
The powder mixture layer 5 is formed by heating and curing the mixed powder 5 for molding to recycle the used discarded plate (step B). The feature of the second regenerating method according to the present invention is that a discarded plate having a large thickness can be easily obtained even from a used discarded plate having a small thickness. Is easily controllable by the number of sheets to be overlapped. In particular, a waste plate having a large thickness is used as a waste plate used in wood processing or the like, and the recycling method of the present invention is effective. In FIG. 5, the used discard plate 3 has a hole on one side only.
However, in the present invention, a used discarded plate having holes on both sides can also be applied.

[0025]

(Example 1) A crushed powder obtained by crushing a used discarding plate for piercing (paper phenol laminate) is sieved (30 mesh), and the powder under the sieving is used as a filling powder. did. As the thermosetting binder resin powder, a phenol resin (Phenolite KI9042, manufactured by Dainippon Ink and Chemicals, Inc.), which is a powder under a 100 mesh sieve containing 8 wt% of hexamethylenetetramine as a curing agent in advance, is used. Was.
Filling powder 85% by weight and thermosetting binder resin powder 1
5 wt% is mixed to produce a mixed powder for molding, charged into a molding die and compression molded (molding temperature 200 ° C., applied pressure 300
kgf / cm2) 200mm x 200mm x 1.
It was formed into a 6 mm plate to obtain a discarded plate for drilling.

(Example 2) The composition of the mixed powder for molding was 94% by weight of the filling powder and 6% of the thermosetting binder resin powder, and was molded into a plate shape in the same manner as in Example 1 to produce a discarded plate for drilling. And

(Example 3) The cut powder of the paper phenol copper-clad laminate was sieved (30 mesh), and the powder under the sieve was used as a filling powder. The content of the cut copper foil powder was measured to be 10% by weight after being separated into cut paper phenol resin powder and cut copper foil powder by specific gravity separation. 85 wt% of the filled powder
And thermosetting binder resin powder 15 used in Example 1
% by weight to prepare a mixed powder for molding.
Under the same conditions as above, compression molding was performed to obtain a discarded plate for drilling.

Example 4 The mixed powder for molding used in Example 1 was charged into a molding die and molded under the same conditions as in Example 1, and a plate having a thickness of 0.4 mm was formed into a high-density layer (density 1.32 g / cc)
Molded as Further, without removing the molded plate, a high-density layer was charged at a weight of 2.4 times the charged amount at the time of molding using a mixed powder having the same composition on the molded plate.
The low-density layer having a thickness of 1.2 mm (1.06 g / c
c) was laminated to form a discarded plate for drilling.

Example 5 Phenolic resin varnish (Phenolite J, manufactured by Dainippon Ink and Chemicals, Inc.) was applied to kraft paper.
-325) was impregnated and dried to prepare a 200 mm x 200 mm prepreg sheet having a phenol resin content of 50 wt%. Lay one prepreg sheet in the mold,
The mixed powder for molding used in Example 1 was charged thereon, and one prepreg sheet was further laminated thereon, compression-molded under a low pressure condition of a molding temperature of 200 ° C. and an applied pressure of 50 kgf / cm 2, and cured. A 1.6 mm-thick discard plate for drilling having a low-density powder molding layer sandwiched between prepreg sheets. The density of the cured prepreg sheet was estimated to be 1.40 g / cc by compressing only 7 prepreg sheets under the same conditions.

Example 6 A used discarded plate having a plurality of holes on its surface (200 mm × 200 mm × 1.6 mm,
A paper phenol laminate) was placed in a molding jig, and the mixed powder for molding used in Example 1 was charged on the surface of the jig.
By performing compression molding under the same conditions as described above, a powder molded layer having a thickness of 0.8 mm was formed on the surface of the used discarded plate to obtain a discarded plate for drilling.

Example 7 83% by weight of a filled powder, 15% by weight of a thermosetting binder resin powder, and silicon oxide fine particles having a primary particle diameter of about 0.016 μm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) ) To 2
The mixed powder for molding was prepared by mixing by weight% and compression-molded under the same conditions as in Example 1 to obtain a discarded plate for drilling.

(Example 8) The crushed powder obtained by crushing the particle board was sieved (30 mesh), and the powder under the sieve was used as a filler powder at 85 wt%, the same thermosetting binder resin powder as in Example 1. A powder mixture for molding was prepared by mixing 15 wt% of the powder, and compression-molded under the same conditions as in Example 1 to obtain a discarded plate for drilling.

(Example 9) Filled powder 8 used in Example 1
5 wt%, a thermosetting binder resin powder used as an epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., Epicoat 100)
15 wt% of powder under 100 mesh sieve obtained by crushing 1)
% To prepare a mixed powder for molding, and compression molded under the same conditions as in Example 1 to obtain a discarded plate for drilling.

(Comparative Example 1) The composition of the powder was 98 wt% of the recycled powder and 2% of the thermosetting binder resin powder, and the powder was molded in the same manner as in Example 1.

The discarded plates obtained in Examples 1 to 9 were all formed into a good plate shape, whereas in Comparative Example 1, the periphery was particularly brittle and a good discarded plate for drilling was used. Could not be obtained. In particular, in Example 7, the mixed powder for molding had high fluidity, and the mixed powder could be easily and uniformly charged in the molding die.

Two printed circuit boards each made of a glass epoxy board are superposed, a 0.2 mm aluminum sheet is used as a backing plate, and the one prepared in Examples 1 to 9 is used as a discarding plate. When drilling was performed, the drilling was successfully performed in each case. Further, when the degree of wear of the drill after drilling was observed with an electron microscope, Examples 1, 2, 3, 6,
Compared to the case where the discarded plates of Nos. 7, 8 and 9 were used, in particular, the degree of wear of drills drilled using the discarded plates of Examples 4 and 5 was smaller.

Further, two printed circuit boards each made of a glass epoxy board were stacked, and the boards prepared in Examples 1 and 2 were used as both a backing board and a discard board, and drilled 5,000 times with a 1 mm diameter drill. Do,
The cross section of the formed through hole was observed with an electron microscope. As a result, when the plate manufactured in Example 2 was used as the backing plate and the discarded plate, the through hole was formed well, but when the plate manufactured in Example 1 was used as the backing plate and the discarded plate, Several places where the melt of the resin material adhered to the wall surfaces of the through holes were confirmed.

[0038]

As described above, by using the discarding plate for drilling according to the present invention, it is possible to recycle cutting powder / abrasive powder / drilling drilling powder / crushed powder and used discarding plate / pattern which have been conventionally discarded. And contribute to resource saving.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a discarding plate for drilling in the present invention.

FIG. 2 is a cross-sectional view showing the configuration of a discarding plate for drilling according to the present invention.

FIG. 3 is a sectional view showing a configuration of a discarding plate for drilling according to the present invention.

FIG. 4 is a cross-sectional view showing a method of recycling a discarded plate for drilling according to the present invention.

FIG. 5 is a cross-sectional view showing a method for regenerating a discard plate for drilling according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 powder molding layer 1a low-density powder molding layer 2 high-density layer 3 used discarded plate 4 hole 5 mixed powder for molding

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaaki Suzuki 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Masahiro Kamakura 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] 1. A prepreg sheet or wood material containing 5 wt% or more of a thermosetting binder resin powder under a 50-mesh sieve and further impregnating a thermosetting resin laminate or a base material with a thermosetting resin varnish. Cutting powder obtained from at least one selected from the plate, abrasive powder, drilling powder, or using a mixed powder for molding containing a filling powder consisting of crushed powder, heat-curing the mixed powder for molding, What is claimed is: 1. A discarding plate for drilling, comprising a powder molded layer molded into a plate shape. 2. The discarding plate for drilling according to claim 1, wherein the filler powder contains a non-ferrous metal powder. 3. The discarding plate for drilling according to claim 1, wherein the thermosetting binder resin powder contains a phenolic resin, and the thermosetting resin laminate is a phenolic resin laminate. 4. The powder molded layer according to claim 1, wherein the powder molded layer has a density of 1.1 g / cc or less, and a high density layer having a density of 1.3 g / cc or more is laminated on the surface of the powder molded layer. A discarding plate for drilling according to any one of the preceding claims. 5. The high-density layer heat-cures a prepreg sheet in which a base material is impregnated with a thermosetting resin varnish, or a cut powder, an abrasive powder, a drilling powder, or a crushed powder obtained from the prepreg sheet. 5. The discarding plate for drilling according to claim 4, wherein the plate is formed by cutting. 6. The powder molded layer contains silicon oxide, aluminum oxide, titanium oxide or carbon black as fine particles having a primary particle diameter of 1 μm or less.
A discarding plate for drilling according to any one of the preceding claims. 7. A used thermosetting resin laminate containing 5 wt% or more of a thermosetting binder resin powder under a 50-mesh sieve with respect to a used discarding plate having one or more holes on its surface. , Or a prepreg sheet impregnated with a thermosetting resin varnish on a base material, or a cutting powder obtained from at least one selected from a wooden material board, an abrasive powder, a drilling powder, or a filling powder comprising a crushed powder. A method of reclaiming a discarded plate for drilling, comprising a step of filling at least a part of the hole using a mixed powder for molding including the same, and a step of heating and curing the mixed powder for molding. 8. A thermosetting resin laminate containing at least 5% by weight of thermosetting binder resin powder under a 50-mesh sieve with respect to a used perforated discarding plate having one or more holes on its surface. , Or a prepreg sheet impregnated with a thermosetting resin varnish on a base material, or a cutting powder obtained from at least one selected from a wooden material board, an abrasive powder, a drilling powder, or a filling powder comprising a crushed powder. A step of filling at least a part of the hole using a mixed powder for molding, a step of stacking a plurality of used drilling discarded plates in which the holes are filled with the mixed powder for molding, and A method for recycling a perforated discarding plate, comprising a step of heat-curing a mixed powder to integrate a plurality of the used perforated discarding plates.