KR101852334B1 - Drill entry sheet - Google Patents

Abstract

The present invention is to provide a drill entry sheet which is excellent in hole position accuracy and reduces the cut-off of a drill bit as compared with a conventional drill entry sheet.
A drill entry sheet comprising a resin composition layer formed on at least one surface of a metal support foil, wherein a solid lubricant containing at least one of zinc molybdate and molybdenum trioxide is added to the resin composition, Wherein the thickness of the drill entry sheet is in the range of 0.02 to 0.3 mm.

Description

Drill Entry Sheet {DRILL ENTRY SHEET}

The present invention relates to a drill entry sheet used for drilling a copper clad laminate or a multilayer plate.

As a method for drilling a copper clad laminate or a multilayer plate used for a material for a printed wiring board, a copper clad laminate or a multilayer board is superimposed on one or a plurality of sheets and a reinforcing board is formed on the top of the copper clad laminate or the multilayer board, A method in which a sheet on which a resin composition layer is formed on a surface (hereinafter, this sheet is referred to as a "drill entry sheet" in the present specification) is placed and drilling is generally employed.

2. Description of the Related Art In recent years, as a demand for a copper clad laminate or a multilayer plate as a material for a printed wiring board, high-quality drilling is required, such as improvement in density, improvement in productivity and cost reduction, improvement in reliability, and improvement in hole location accuracy have. In order to cope with these demands, for example, in Patent Document 1, a drilling method using a sheet made of a water-soluble resin such as polyethylene glycol has been proposed. Further, in Patent Document 2, a drill lubricant sheet in which a water-soluble resin layer is formed on a metal foil is proposed. Patent Document 3 proposes a drill entry sheet in which a water-soluble resin layer is formed on an aluminum foil on which a thin film of a thermosetting resin is formed. In addition, in Patent Documents 4 to 5, an auxiliary material for prolonging the life of a drill bit by blending nano powder has been proposed.

However, compared with advances in semiconductor technology, the progress of printed wiring board technology is slower, and there is a gap with semiconductor technology. For this reason, demands for higher densification and improved reliability of the printed wiring board are becoming more and more advanced. For example, the minimum drill bit diameter in mass production is shifted from 0.2 mm in diameter to 0.105 mm in diameter through 0.18 mm in diameter and 0.15 mm in diameter. In addition, drilling of 0.08 mm phi, 0.075 mm phi, and 0.05 mm phi is attempted against a laser drilling technique in a very small part. Furthermore, the demand for productivity improvement and cost reduction continues to increase in order to compete with globalization and to accept demand from emerging countries. Therefore, development of a new drill entry sheet according to such a demand is being sought.

Japanese Patent Application Laid-Open No. H04-92494 Japanese Patent Application Laid-Open No. H05-169400 Japanese Patent Application Laid-Open No. 2003-136485 Japanese Utility Model No. 3134128 Japanese Patent Application Laid-Open No. 2007-281404

SUMMARY OF THE INVENTION An object of the present invention is to provide a drill entry sheet excellent in hole position accuracy as compared with a conventional drill entry sheet in view of such a phenomenon. Such a drill entry sheet is desired to be developed in order to contribute to high density, high reliability, productivity, and cost reduction.

As a result of various studies to solve the above problems, the present inventors have found that, as a solid lubricant (B), at least one of zinc molybdate and molybdenum trioxide is blended in the resin composition of the drill entry sheet, . Thus, it has been found that the accuracy of the hole position is improved by making the drill bit easier to swallow and improving the perforation of the drill bit. Further, since the lubricating action of zinc molybdate and molybdenum trioxide increases the lubricity and smooth discharge of cutting chips, the cuttings are prevented from being clumped and falling, It is possible to prevent the problem of drill bit breakage due to stepping.

Here, the afferent means the straightness of the cutting direction at the time of cutting. For example, at the point where the drill bit touches the resin composition layer of the drill entry sheet, the cutting blade at the tip of the rotating drill bit slides and bites the surface of the resin composition layer. Not only the lubrication is increased but also the cutting edge at the tip of the drill bit is easily slid laterally (side slip), thereby deteriorating the perforation and deteriorating hole position accuracy.

The present invention has been made on the basis of this finding, and its main points are as follows.

(1) A drill entry sheet in which a layer made of a resin composition is formed on at least one surface of a metal support foil, wherein the resin composition contains at least one of molybdenum zinc and molybdenum trioxide as a solid lubricant (B) Wherein the thickness of the composition layer is in the range of 0.02 to 0.3 mm.

(2) The drill entry sheet according to the above (1), wherein the resin composition comprises a water-soluble resin (A).

(3) The drill entry sheet according to (1), wherein the resin composition is formulated in a total amount of 1 to 40 parts by weight of the solid lubricant (B) per 100 parts by weight of the resin.

(4) The drill entry sheet according to (1), wherein the zinc molybdate has an average particle diameter of 1 to 7 mu m.

(5) The drill entry sheet according to (1), wherein the molybdenum trioxide has an average particle diameter of 3 to 35 mu m.

(6) The drill entry sheet according to (1), wherein the drill bit diameter is 0.2 mm or less.

(7) The drill entry sheet according to (1), wherein the metal support foil has a thickness of 0.05 to 0.5 mm.

(8) The drill entry sheet according to (1), wherein the metal support foil has a primer layer as a resin coating.

(9) The drill entry sheet according to (8), wherein the primer layer contains the solid lubricant (B).

(10) The drill entry sheet according to (9), wherein the amount of the solid lubricant (B) in the primer layer is 1 part by weight to 20 parts by weight per 100 parts by weight of the composition of the primer.

(11) The drill entry sheet according to the above (1), which is used for processing a copper-clad laminate or a multilayer plate.

By using the drill entry sheet of the present invention, it is possible to reduce the cut-off of the drill bit at the time of drilling due to the excellent hole position accuracy at drilling and the excellent lubricity of the resin composition layer. As a result, high-density design becomes possible, and high-quality, high-productivity drilling becomes possible. Alternatively, it is possible to increase the number of superimposing steps for drilling at one time, thereby contributing to improvement in productivity and cost reduction.

1 is a scanning electron micrograph (x 10000) (made by Nippon Inorganic Color & Chemical Co., Ltd., particle diameter 0.4 탆 to 13 탆, average particle diameter 3 탆, layered structure) of zinc molybdate .
2 is a scanning electron micrograph (x 10000) (Nippon Inorganic Color & Chemical Co., Ltd., particle size 0.7 to 55 μm, average particle diameter 16 μm, columnar structure) of molybdenum trioxide.
Fig. 3 is a comparison of hole positional accuracy in Examples and Comparative Examples when machined under drilling conditions 1; Fig.
Fig. 4 is a comparison of hole positional accuracy in Examples and Comparative Examples when machined under drilling conditions 2; Fig.

The drill entry sheet of the present invention is a drill entry sheet in which a layer made of a resin composition (hereinafter referred to as " resin composition layer ") is formed on at least one surface of a metal support foil. The drill entry sheet of the present invention is characterized in that the resin composition contains a solid lubricant (B).

In the present invention, the solid lubricant (B) is any solid used as a thin film or powder to protect the surface from damage during relative movement and to reduce friction and wear, has a melting point of 300 ° C or higher, Means that it is thermally stable in the air at a temperature higher than the use temperature of 200 占 폚 and is not melted but solid.

As the solid lubricant (B), the amount of at least one of zinc molybdate and molybdenum trioxide is optimized. As a result, the drill bit is easily wasted and the perforation of the drill bit is improved, so that the accuracy of the hole position is improved. Further, since the lubrication is enhanced and the discharge of the cutting fluid becomes smooth, This contributes to preventing the problem of drill bit breakage as the drill bit is stepped on the agglomerated cuts.

The resin composition of the present invention is preferably a composition containing the water-soluble resin (A). Here, the water-soluble resin (A) refers to a water-soluble resin and a water-soluble lubricant other than the solid lubricant (B).

Of course, the resin composition may contain, for example, a nucleating agent, a colorant, a heat stabilizer and the like as a known thermoplastic water-insoluble resin, a non-water-soluble lubricant which is not a solid lubricant (B), and other additives.

The resin component of the resin composition refers to a water-insoluble lubricant other than the water-soluble resin (A), the solid lubricant (B), and a thermoplastic water-insoluble resin. In addition to its original role, the resin component of the resin composition also serves as a carrier for transporting the solid lubricant (B) to the drill bit and the printed wiring board material.

The solid lubricant (B) is compounded in an amount of 1 part by weight to 40 parts by weight based on 100 parts by weight of the resin component of the resin composition, preferably 1 part by weight to 30 parts by weight, more preferably 5 parts by weight to 20 parts by weight More preferably from 10 parts by weight to 20 parts by weight, and most preferably from 10 parts by weight to 20 parts by weight. When the solid lubricant (B) is less than 1 part by weight, the effect is not exhibited. When the solid lubricant (B) exceeds 40 parts by weight, there is no economic rationality, and the solid lubricant (B) easily agglomerates. As a result, manufacturing difficulties may occur, and as a result, hole position accuracy may deteriorate.

In the present invention, the solid lubricant (B) is at least one of zinc molybdate (MoO ₄ Zn, melting point 900 ° C) and molybdenum trioxide (MoO ₃ , melting point 795 ° C). Although molybdenum trioxide has been conventionally known to exhibit no solid lubricity, it has been found useful as a solid lubricant (B) to be incorporated in a drill entry sheet. The solid lubricant (B) may contain at least one of these.

The solid lubricant (B) is preferable because it exhibits a remarkable action effect in a small amount as compared with a solid lubricant such as molybdenum disulfide and mica. It is also preferable from the standpoint of widening the choice of the resin as the resin composition to manifest a remarkable action effect in a small amount.

The mechanism of action of the solid lubricant (B) is believed to be approximately as follows. First, by including a solid of a suitable hardness in the lubricant layer, the tip of the drill bit contacts the solid lubricant B and bites. Therefore, the initial hole position accuracy is good. Second, the solid lubricant (B) is added to the surface of the drill bit and the hole wall of the material of the printed wiring board, because the solid lubricant (B) is added to the lubricant layer. Since the solid lubricant (B) is solid and has a volume and a hardness, it is always present between the copper clad laminate or the multilayer plate and the drill bit to increase the lubricity and suppress the wear of the drill bit. Third, since the solid lubricant B is adhered to the groove of the drill bit, the lubricating action is enhanced by the solid lubricating action, and the smoothness of the discharge of the cutting powder is suppressed.

However, wear of the drill bit can be classified into two types. First, there is initial wear. That is, when the drill bit starts to be used, the impacted portion is broken. Owing to the remarkable lubrication effect peculiar to the solid lubricant (B) described above, the initial wear of the drill bit is suppressed as compared with the case where the solid lubricant (B) is not contained. Secondly, there is normal wear. That is, the drill bit is worn together with the cumulative drilling number. However, since there is a lubrication effect peculiar to the solid lubricant (B), the normal wear rate is also suppressed as compared with the case where the solid lubricant (B) is not contained. Therefore, when the solid lubricant (B) is not contained, the hole position accuracy deteriorates in proportion to the cumulative drilling number, but when the solid lubricant (B) is contained, the hole position accuracy may be gradually suppressed.

The solid lubricant (B) may be compounded in a resin coating (hereinafter sometimes referred to as a primer layer) provided on the metal supporting foil. Since the primer layer is in contact with the aluminum foil, finely filling the primer layer contributes to hole position accuracy. The total amount of the solid lubricant (B) is 1 part by weight to 20 parts by weight based on 100 parts by weight of the composition of the primer, more preferably 5 parts by weight to 10 parts by weight. When the blending amount of the solid lubricant (B) is less than 1 part by weight, the effect is not exhibited. If the blending amount of the solid lubricant (B) exceeds 20 parts by weight, there is no economical rationality and the adhesion between the thin layer of the primer layer and the metal supporting foil may be inhibited. The resin of the primer layer containing the solid lubricant (B) can be applied to both the thermosetting resin and the thermoplastic resin. The resin of the primer layer is preferably a thermosetting resin, and is more preferable for hole position accuracy.

It is more preferable that the solid lubricant (B) is selected in the optimum kind, particle diameter, and blending amount in accordance with the specification of the copper clad laminate or the multilayer plate.

The reason why the solid lubricant (B), for example, zinc molybdate shows an effect is as follows. Zinc molybdate is a layered structure, having a particle diameter of 0.2 to 15 탆, an average particle diameter of 1 to 7 탆, and a solid having a volume and an appropriate hardness. Preferably an average particle diameter of 2 to 6 mu m. More preferably an average particle diameter of 3 to 5 占 퐉. Because of its characteristics, drill bits are liable to be biting in small diameter drill bits where hole position accuracy is important. Further, zinc molybdate is a layered structure and thin, which is easy to be entrained in the grooves when the drill bit is rotated, thereby contributing to the discharge of the cutting powder.

The reason why molybdenum trioxide exhibits the action effect is as follows. Molybdenum trioxide oxidizes molybdenum disulfide and has a columnar structure, a particle diameter of 0.7 to 55 μm, an average particle diameter of 3 to 35 μm, and a solid with a volume and an appropriate hardness. Preferably an average particle diameter of 5 to 20 占 퐉. More preferably an average particle diameter of 10 to 18 占 퐉. Due to its characteristics, drill bit is liable to be biting in a small diameter drill bit where hole position accuracy is important. Since molybdenum trioxide has a smaller average particle diameter than the depth of the grooves of the drill bit, the molybdenum trioxide contributes to the discharge of the cutting powder since the molybdenum trioxide tends to get caught in the grooves during rotation of the drill bit.

With respect to the particle diameter of the solid lubricant (B), the average particle diameter value is more important than the maximum particle diameter value. This is because the particle size of the solid lubricant having a high proportion in the resin composition affects hole position accuracy and lubricity, which are characteristics of the drill entry sheet. Therefore, it is important to manage the average particle diameter of the solid lubricant (B) in order to improve the performance of the drill entry sheet. Therefore, the ratio of the maximum particle size to the particle size distribution of the solid lubricant (B) is high, and raising the average particle diameter value is not preferable because it may reduce the solid lubricity which is originally expected. The particle size of the solid lubricant (B) was measured by dispersing a sample in a solution of 0.2% hexametaphosphoric acid solution and a few drops of 10% Triton, and measuring the particle size of the solid lubricant (B) using a laser diffraction particle size distribution analyzer (model number: SALD-2100, manufactured by Shimadzu Corporation) , The maximum length of each particle of the projected solid lubricant (B) is measured. Then, the particle size distribution curve is calculated. The range of the curve was defined as the particle diameter of the solid lubricant (B), and the particle diameter at the peak of the component amount peak of the curve was taken as the average particle diameter.

In particular, when the solid lubricant (B) is zinc molybdate and molybdenum trioxide, it is not completely insoluble in water but is non-swellable. Therefore, as in the case of the swelling solid lubricant, it is industrially advantageous because it is not necessary to strictly control the moisturizing degree. Here, the non-swelling property is defined as follows. The solid lubricant is stirred until an aqueous solution containing 10 parts by weight of a solid lubricant is sufficiently mixed with 90 parts by weight of water, and the sedimentation height of the solid lubricant is measured after standing for 1 hour. Or more of the sedimentation rate, 50% to less than 90% of the sedimentation height ratio, and less than 50% of the sedimentation height ratio is defined as non-swelling. In the zinc molybdate of the present invention, there is an example in which the height to the liquid surface is 66 mm, the upper surface of the settling portion of the zinc molybdate is 21 mm, and the settling height ratio is 32%. Likewise, in the molybdenum trioxide of the present invention, the height to the liquid surface is 35 mm, the top surface of the settling portion of molybdenum trioxide is 5 mm, the settling height ratio is 14%, and the top surface of the settling portion of molybdenum trioxide is cloudy to the liquid surface.

This property has the following advantages in producing a solution of the water-soluble resin (A). They tend to be uniformly dispersed and are difficult to aggregate. After the drilling, if molybdenum molybdate or molybdenum trioxide remains in the hole, it is easy to clean. However, when the solution of the water-soluble resin (A) is produced, since the concentration gradient of the solid lubricant (B) is formed, stirring is required.

The hardness of the solid lubricant (B) is not suitable, for example, a region exceeding the Moh hardness of 5 is an abrasive. The optimum blending amount of the solid lubricant (B) differs from the specification of the printed wiring board to be drilled. Compared to a printed wiring board material not containing an inorganic filler, a printed wiring board material containing an inorganic filler has a relatively large amount of wear on the drill bit, so it is sometimes preferable to blend a large amount of the solid lubricant (B).

The kind of the water-soluble resin (A) is not particularly limited, and examples of the water-soluble resin include polyethylene oxide, polypropylene oxide, sodium polyacrylate, polyacrylamide, polyvinylpyrrolidone, carboxymethylcellulose, Methylene glycol, and poly (alkylene glycol), and more preferably at least one selected from the group consisting of poly (methylene glycol) and poly (alkylene glycol). Polyester of polyalkylene glycol is a condensate obtained by reacting polyalkylene glycol with dibasic acid. Examples of polyalkylene glycols include glycols exemplified by polyethylene glycol, polypropylene glycol, polytetramethylene glycol and copolymers thereof, and polyhydric alcohols such as phthalic acid, isophthalic acid, terephthalic acid, sebacic acid and pyromellitic acid as dibasic acids Partial esters of carboxylic acids, acid anhydrides, and the like. As the water-soluble lubricant other than the solid lubricant (B), for example, polyethylene glycol, polypropylene glycol; Polyoxyethylene monoethers such as polyoxyethylene oleyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether and polyoxyethylene octylphenyl ether, Ryu; Polyoxyethylene monostearate, polyoxyethylene sorbitan monostearate; Polyglycerin monostearates exemplified by hexaglycerin monostearate, decahexa glycerin monostearate and the like; Polyoxyethylene propylene copolymer, and the like, and it is preferable to use one kind or two or more kinds thereof appropriately.

The thermoplastic, water-insoluble resin is not particularly limited, and known materials can be applied. For example, there can be used an elastomer such as amide elastomer, butadiene elastomer, ester elastomer, olefin elastomer, urethane elastomer, styrene elastomer, polybutene, low density polyethylene, chlorinated polyethylene, metallocene polyolefin resin, ethylene- (Meth) acrylate copolymer, an ethylene · vinyl acetate copolymer resin, a modified ethylene · vinyl acetate copolymer resin, an ethylene · (meth) acrylic acid copolymer resin, an ionomer resin, an ethylene · (meth) Ester copolymer resins and the like.

The non-water-soluble lubricant other than the solid lubricant (B) is not particularly limited, and known materials can be applied. Examples thereof include amide compounds exemplified by ethylenebisstearamide, oleic acid amide, stearic acid amide, methylene bisstearamide and the like, fatty acid compounds exemplified by lauric acid, stearic acid, palmitic acid, oleic acid and the like, butyl stearate, Fatty acid ester compounds exemplified by butyl oleate and lauric acid glycol, aliphatic hydrocarbon compounds exemplified by liquid paraffin and polyethylene wax, and higher aliphatic alcohols exemplified by oleyl alcohol and the like.

The thickness of the resin composition layer varies depending on the diameter of the drill bit used for drilling, the constitution of the copper clad laminate or the multilayer plate to be processed, and is usually in the range of 0.02 to 0.3 mm, preferably in the range of 0.02 to 0.2 mm Is preferably selected. If the thickness of the resin composition layer is less than 0.02 mm, a sufficient lubrication effect can not be obtained, and the load on the drill bit becomes large and the drill bit may be cut off. On the other hand, if the thickness of the resin composition layer exceeds 0.3 mm, the winding of the resin composition with the drill bit may increase.

As a method of forming the resin composition layer, there can be employed a method in which a heat dissolver or a solution of a resin composition is coated directly on the metal support foil by a coating method or the like and then dried, And a hot melt method in which the metal support foil is bonded to the metal support foil. At this time, since the resin coating (primer layer) is previously formed on the metal supporting foil, the metal supporting foil and the resin composition layer are laminated and integrated, which is preferable. The details will be described later.

Furthermore, in the case of adopting a coating method or the like in which the solution of the resin composition is applied directly on the metal support foil and dried, the solution used is preferably a solution containing water and a solvent having a lower boiling point than water. Examples of the solvent having a lower boiling point than water include, but are not limited to, ethanol such as alcohols, methanol or isopropyl alcohol, and a low boiling point solvent such as methyl ethyl ketone or acetone. As other solvent, a solvent in which tetrahydrofuran or acetonitrile partially mixed with water or alcohols having high compatibility with the resin composition can be used. The mixing ratio of water to a solvent having a boiling point lower than water is required to be in the range of 90/10 to 50/50 and preferably in the range of 80/20 to 50/50 and more preferably in the range of 70/30 to 50/50 , More preferably in the range of 60/40 to 50/50. When the compounding ratio of the solvent having a lower boiling point than water is less than 10, the water-soluble resin (A) may be difficult to produce dense spherical crystals. If the blending ratio of the solvent having a lower boiling point than water is more than 50, there is a fear that the industrial stable production may be hindered.

When the solution of the resin composition is coated directly on the metal support foil by a coating method or a hot melt method or the like and heated and dried, the temperature of the drill entry sheet is increased from 120 ° C to 160 ° C, It is necessary to set the temperature to room temperature in a second. A drying temperature higher than 160 DEG C is undesirable because it may interfere with industrial stable production. Further, a cooling temperature lower than room temperature may cause condensation in a subsequent step, which is not preferable.

The metal support foil used in the drill entry sheet of the present invention is not particularly limited as long as the metal support foil has high adhesion with the resin composition and can withstand a shock caused by a drill bit. The thickness of the metal support foil is usually 0.05 to 0.5 mm, preferably 0.05 to 0.3 mm. If the thickness of the metal supporting foil is less than 0.05 mm, burrs of the laminated board tend to occur at the time of drilling. If the thickness is more than 0.5 mm, it may be difficult to discharge the cuttings generated at the time of drilling. As the metal species of the metal support foil, for example, aluminum can be used. As the material of the aluminum foil, aluminum having a purity of 95% or more is preferable. For example, 5052, 3004, 3003, 1N30, 1N99, 1050, 1070, 1085 and 8021 specified in JIS-H4160 are exemplified. By using a high purity aluminum foil for the metal support foil, the impact by the drill bit is alleviated and the biting property with the tip of the drill bit is improved. In addition to the lubrication effect of the drill bit by the resin composition, The hole position accuracy of the hole can be increased. From the viewpoint of adhesion with the resin composition, it is preferable to use a metal supporting foil in which a resin coating (primer layer) having a thickness of 0.002 to 0.02 mm is formed on the surface in advance. When the solid lubricant (B) is compounded in the resin coating, the thickness of the resin coating is appropriately selected according to the particle diameter of the solid lubricant (B). The resin used for the resin film is not particularly limited as long as it can improve the adhesion with the resin composition, and any of a thermoplastic resin and a thermosetting resin can be used. For example, examples of the thermoplastic resin include a urethane polymer, a vinyl acetate polymer, a vinyl chloride polymer, a polyester polymer, an acrylic polymer, and copolymers thereof. Examples of the thermosetting resin include resins such as an epoxy resin and a cyanate resin.

The drill entry sheet of the present invention is used for drilling a printed wiring board material, for example, a copper-clad laminate or a multilayer board. Concretely, a drill entry sheet is disposed on the top of a copper clad laminate or a multilayer plate in which one or a plurality of the copper clad laminate is laminated, and the metal support foil side is in contact with the printed wiring board material. .

The foregoing is merely an example of an embodiment of the present invention and can be variously modified within the scope of the claims.

Example

Hereinafter, the effects of the embodiments of the present invention will be described in comparison with comparative examples deviating from the scope of the present invention. On the other hand, "polyethylene glycol" is abbreviated as "PEG" and "polyethylene oxide" is abbreviated as "PEO".

≪ Example 1 >

30 parts by weight of polyethylene oxide having a weight average molecular weight of 150,000 (ALTOP MG-150, manufactured by Meisei Chemical Works, Ltd.) and 70 parts by weight of polyethylene glycol having a weight average molecular weight of 20,000 (PEG20000, manufactured by Sanyo Chemical Industries, Ltd.) Was dissolved in a water / MeOH (methanol) mixed solution so as to be 30%. The ratio of water to MeOH was 60/40. To the solution of the water-soluble resin composition was added 100 parts by weight of molybdenum zincate (manufactured by Nippon Inorganic Color & Chemical Co., Ltd., particle diameter: 0.4 mu m to 13 mu m, average particle diameter: 3 mu m) as a solid lubricant 5 parts by weight based on 100 parts by weight of the total of the components. The solution of the water-soluble resin composition was dried using a bar coater on an aluminum foil (used aluminum foil: 1N30, thickness 0.1 mm, manufactured by Mitsubishi Aluminum Co., Ltd.) having an epoxy resin coating with a thickness of 0.01 mm formed on one side thereof The resulting water-soluble resin composition layer was applied so as to have a thickness of 0.05 mm, dried at 120 DEG C for 5 minutes in a drier, and then cooled to room temperature to prepare a drill entry sheet.

≪ Examples 2 to 14 >

A water-soluble resin composition shown in Table 1 was prepared in accordance with Example 1 to prepare a drill entry sheet having a thickness of the dried water-soluble resin composition layer of 0.05 mm.

≪ Comparative Examples 1 to 11 &

A water-soluble resin composition shown in Table 1 was prepared in accordance with Example 1 to prepare a drill entry sheet having a thickness of the dried water-soluble resin composition layer of 0.05 mm.

<Evaluation method>

The following evaluations were carried out on each sample of the drill entry sheet produced in the examples and the comparative examples.

(1) Hole position accuracy

On top of the laminated copper-clad laminate, the drill entry sheet was arranged with its resin composition layer up, and drilling was carried out. 6,000 hits per drill bit was drilled and repeated with four drill bits. For holes of 1 to 1,500 and 1 to 6,000 hours per one drill bit, the displacement of the hole position in the back surface of the lowest plate of the laminated copper-clad laminate and the designated coordinates is measured with a hole analyzer (model number: HA-1AM , Hitachi Via Mechanics, Ltd.), and the average value and the standard deviation (?) Were calculated to calculate the "average value + 3σ". The mean value of "average value + 3σ" of four drill bits was calculated. The results are shown in Table 1.

As a criterion for determining the accuracy of the hole position, it is determined by the hole position accuracy of 1 to 1,500 hours in which the drill bit wear does not proceed and the hole position accuracy of 1 to 6,000 hours in which the drill bit wear has progressed. When the judgment at the time of 1 to 1,500 and 1 to 6,000 hours is &quot;? &Quot;, it is set to &quot;? &Quot;

(2) Particle size measurement method of solid lubricant (B)

The particle size of the solid lubricant (B) was measured by dispersing a sample in a solution of 0.2% hexametaphosphoric acid solution and a few drops of 10% Triton, and measuring the particle size of the solid lubricant (B) using a laser diffraction particle size distribution analyzer (model number: SALD-2100, manufactured by Shimadzu Corporation) , The maximum length of each particle of the projected solid lubricant (B) is measured. Then, the particle size distribution curve is calculated. The range of the curve was defined as the particle diameter of the solid lubricant (B), and the particle diameter at the peak of the component amount peak of the curve was taken as the average particle diameter.

[Table 1]

Composition of water-soluble resin (A):

1) 30 parts by weight of polyethylene oxide (manufactured by Meisei Chemical Works, Ltd., ALTOP MG-150, Mw = 150,000), 70 parts by weight of polyethylene glycol (PEG20000, Mw = 20,000, manufactured by Sanyo Chemical Industries, Ltd.) part.

2) 20 parts by weight of polyetherester (Paogen PP-15, Mw = 100,000, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), 80 parts by weight of polyethylene glycol (PEG4000S, manufactured by Sanyo Chemical Industries, Ltd., Mw = 4,000) Part, 100 parts by weight in total.

Type of solid lubricant (B):

3) zinc molybdate (made by Nippon Inorganic Color & Chemical Co., Ltd., particle size: 0.4 탆 to 13 탆, average particle size: 3 탆, layered structure)

4) molybdenum trioxide (particle diameter 0.7 탆 to 55 탆, average particle diameter 16 탆, columnar structure, manufactured by Nippon Inorganic Color & Chemical Co.,

5) Molybdenum disulfide (M-5 Powder, Daizo Corporation, particle size 0.5 to 29 탆, average particle size 5 탆, layered structure)

6) Swellable mica (ME-100, particle diameter 5 to 7 μm, layered structure, manufactured by Co-op Chemical Co., Ltd.)

7) Non-swellable mica (MK-200, particle diameter 5 to 8 μm, layered structure, manufactured by Co-op Chemical Co., Ltd.)

8) Solid lubricant (B) Unformulated

The amount of the solid lubricant (B)

The solid lubricant (B) contains one of 0, 5, 10, 20, 40, 60, and 80 parts by weight based on 100 parts by weight of the resin component of the resin composition.

Drilling conditions:

1) Drilling bit diameter: 0.2 mm (Tungaloy Corporation, C-CFU020S), revolution number: 200,000 rpm, conveying speed: 20 탆 / rev., Rising speed: 25.4 m / No HL832 0.2mmt, Cu12μ, 5 sheets overlapping

2) Drill bit diameter: 0.2 mm (Tungaloy Corporation, C-CFU020S), number of revolutions: 200,000 rpm, conveying speed: 20 탆 / rev., Rising speed: 25.4 m / min, HL832HS0.2mmt, Cu12μ, 5 sheets stacked

From the results shown in Table 1, it can be seen that the samples of Examples 1 to 14 are superior in hole position accuracy to the samples of Comparative Examples 1 to 11, both at the stage where the drill bit wear has not progressed and at the stage where the wear has progressed. That is, the molybdenum molybdate and molybdenum trioxide of the present invention are significantly superior in hole position accuracy to molybdenum disulfide, swelling mica, and non-swelling mica, which are prior arts.

Industrial availability

According to the present invention, it is possible to provide a drill entry sheet in which hole position accuracy is excellent and cut-off of a drill bit is reduced as compared with a conventional drill entry sheet.

Claims (11)

Wherein the resin composition comprises at least one of zinc molybdate and molybdenum trioxide as a solid lubricant (B), and the resin composition layer Wherein the thickness of the drill entry sheet is in the range of 0.02 to 0.3 mm.
The method according to claim 1,
A drill entry sheet characterized in that the resin composition comprises a water-soluble resin (A).
The method according to claim 1,
Wherein the resin composition comprises 1 to 40 parts by weight of the solid lubricant (B) in a total amount of 100 parts by weight of the resin component (resin component).
The method according to claim 1,
Wherein the zinc molybdate has an average particle diameter of 1 to 7 mu m.
The method according to claim 1,
Wherein the molybdenum trioxide has an average particle diameter of 3 to 35 占 퐉.
delete The method according to claim 1,
Wherein the metal support foil has a thickness in the range of 0.05 to 0.5 mm.
The method according to claim 1,
Wherein the metal support foil has a primer layer which is a resin coating on the metal support foil.
9. The method of claim 8,
Characterized in that the primer layer contains the solid lubricant (B).
10. The method of claim 9,
Wherein a blending amount of the solid lubricant (B) in the primer layer is 1 part by weight to 20 parts by weight per 100 parts by weight of the composition of the primer.
The method according to claim 1,
Wherein the drill entry sheet is used for machining a copper clad laminate or a multilayer plate.

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