KR101859699B1 - Drill entry sheet - Google Patents

Abstract

Provided is a drill entry sheet which has higher lubrication effect, smaller hole wall roughness, and higher hole position accuracy than a conventional drill entry sheet. A drill entry sheet comprising a layer of a resin composition formed on at least one surface of a metal support foil, wherein the resin composition comprises a water-soluble resin containing a specific polyethylene glycol-polypropylene glycol-block copolymer and polyethylene oxide And the thickness of the resin composition layer is in the range of 0.02 to 0.2 mm.

Description

Drill Entry Sheet {DRILL ENTRY SHEET}

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 plate may be laminated one or more, and a metal foil such as aluminum or a metal support foil A method in which a sheet on which a resin composition layer is formed on a surface (hereinafter, this sheet is generally referred to as a "drill entry sheet" in the present specification) is disposed and pierced is generally employed.

In recent years, there has been a demand for a copper clad laminate or a multilayer plate, which is a material for a printed wiring board, as advancing of high density, improvement of productivity, cost reduction, reliability improvement, high quality drilling such as improvement of hole position accuracy and reduction of hole wall roughness have. In order to cope with such a demand, for example, Patent Document 1 proposes a punching method using a sheet made of a water-soluble resin such as polyethylene glycol. Further, Patent Document 2 proposes a perforating lubricant sheet in which a water-soluble resin composition containing a polyether ester and a lubricant component is formed. Patent Document 3 proposes a method for manufacturing a blank for an entry sheet in which a water-soluble resin layer is formed on an aluminum foil by using a solution obtained by dissolving a water-soluble resin in a mixed solvent of water and IPA.

However, compared with advances in semiconductor technology, the progress of printed wiring board technology is slow and there is a gap with semiconductor technology. Therefore, demands for higher densification and improved reliability of the printed wiring board are further advanced. Also, due to competition from globalization and take-up of demand from emerging countries, productivity and cost reduction requirements are also increasing. Therefore, there is a demand for development of a new drill entry sheet to meet such a demand.

Japanese Patent Application Laid-Open No. 4-92494 Japanese Patent Application Laid-Open No. 6-344297 Japanese Patent Application Laid-Open No. 2007-324183

SUMMARY OF THE INVENTION An object of the present invention is to provide a drill entry sheet in which a lubrication effect during drill drilling is large, hole wall roughness is reduced, and hole position accuracy is improved as compared with a conventional drill entry sheet. In order to reduce the wall roughness of the hole, it is necessary to increase the lubricity of the resin composition layer more than conventionally. In the prior art, it has been very difficult to achieve both reduction of hole wall roughness and improvement of hole position accuracy.

At the point where the drill bit touches the resin composition layer of the entry sheet, the cutting blade at the tip of the rotating drill bit sticks to the surface of the resin composition layer while slidably moving. Simply by raising the lubricity, the drill bit is likely to slip, so the perforation is deteriorated and the accuracy of the hole position is deteriorated. The centroid mentioned here refers to the straightness in the cutting direction at the time of cutting. As a result of various studies to solve the above problems, the present inventors have found that by mixing a polyethylene glycol-polypropylene glycol-block copolymer having a specific structure and a molecular weight in an appropriate amount into the resin composition, The discharging property of the chips (chip) was improved, the hole wall roughness was reduced, and the hole position accuracy was improved. Particularly, it has been shown that the above problems can be solved without deteriorating hole position accuracy by improving the lubricity while keeping the austenitivity by blending the block copolymer in an appropriate amount.

The present invention is based on this knowledge, and the gist of the invention is as follows.

(1) A drill entry sheet having a layer of a resin composition formed on at least one surface of a metal support foil, wherein the resin composition comprises polyethylene glycol (PEG), polypropylene glycol (PPG) (A) and 70 to 97 parts by weight of a water-soluble resin (B) containing polyethylene oxide (PEO), wherein the polyethylene glycol · polypropylene glycol · block copolymer (A) (B) is 100 parts by weight, the polyethylene glycol-polypropylene glycol-block copolymer (A) has a PEG / PPG ratio of 0.1 to 1 on average and a number average molecular weight of 1,800 to 4,000, Wherein the thickness of the drill entry sheet is in the range of 0.02 to 0.2 mm.

[Chemical Formula 1]

(1, m, n in the formula (1) is a repetition number and is an integer of 1 or more.)

The term "PEG / PPG ratio" indicates the weight ratio of polyethylene glycol and polypropylene glycol constituting the block copolymer. &Quot; Polyethylene glycol " .

(2) The drill entry sheet according to (1), wherein the content of the polyethylene glycol (PEG) -Polypropylene glycol (PPG) block copolymer (A) is 5 to 15 parts by weight.

(3) The PEG / PPG ratio of the polyethylene glycol-polypropylene glycol-block copolymer (A) is 0.1 or more and less than 0.3, and the number average molecular weight is 1,900 or more and less than 2,200. Sheet.

(4) The PEG / PPG ratio of the polyethylene glycol-polypropylene glycol-block copolymer (A) is 0.1 or more and less than 0.3, and the number average molecular weight is 2,220 or more and less than 2,400. Sheet.

(5) The PEG / PPG ratio of the polyethylene glycol-polypropylene glycol-block copolymer (A) is 0.3 or more and less than 0.7, and the number average molecular weight is 2,400 or more to 2,800 or less. Sheet.

(6) The PEG / PPG ratio of the polyethylene glycol-polypropylene glycol-block copolymer (A) is not less than 0.7 and not more than 1, and the number average molecular weight is not less than 2,800 and less than 3,330. Sheet.

(7) The PEG / PPG ratio of the polyethylene glycol-polypropylene glycol-block copolymer (A) is 0.7 to 1, and the number average molecular weight is 3,330 to 4,000. Sheet.

(8) The drill entry sheet according to (1), wherein the polyethylene oxide contained in the water-soluble resin (B) has a number average molecular weight of 50,000 or more and 1,000,000 or less.

(9) The method according to any one of (1) to (9), wherein the blending amount of polyethylene oxide contained in the water-soluble resin (B) in the total of 100 parts by weight of the polyethylene glycol-polypropylene glycol- (1). ≪ / RTI >

(10) The drill entry sheet according to (1) above, wherein the water-soluble resin (B) contains polyethylene glycol having a number average molecular weight of 20,000 or less.

(11) The process for producing a water-soluble resin (B) according to any one of (1) to (11), wherein the amount of polyethylene glycol contained in the water-soluble resin (B) in the total of 100 parts by weight of the polyethylene glycol / polypropylene glycol- (1). ≪ / RTI >

(12) The resin composition preferably comprises 3 to 30 parts by weight of the polyethylene glycol-polypropylene glycol-block copolymer (A), 5 to 50 parts by weight of a polyethylene oxide having a number average molecular weight of 50,000 or more as a water-soluble resin (B) A drill entry sheet according to the above (1), characterized by comprising 20 to 92 parts by weight of polyethylene glycol having a molecular weight of 20,000 or less.

(13) The drill entry sheet according to (1) above, wherein the resin composition has a solidification point of from 40 캜 to 44 캜.

(14) The resin composition as described in (1) above, wherein the resin composition layer is formed by applying a resin composition solution obtained by dissolving the resin composition in a solvent on at least one side of the metal support foil, ≪ / RTI >

(15) A drill according to (14), characterized in that a resin composition layer is formed by using a mixed solvent of water and a solvent having a lower boiling point than water as a solvent used for solution of the resin composition Entry sheet.

(16) A drill entry sheet according to the above (1), characterized in that a layer of a thermosetting resin or a thermoplastic resin is formed on at least one surface of a metal support foil in advance and a layer made of the resin composition is formed thereon .

(17) The drill entry sheet according to (16), wherein the thickness of the thermosetting resin or thermoplastic resin layer is 0.001 to 0.02 mm.

(18) The drill entry sheet according to (14), wherein the cooling step is performed at a temperature of 120 ° C to 160 ° C for 5 to 30 seconds to 20 ° C to 40 ° C.

(19) The drill entry sheet according to (1), wherein the thickness of the metal support foil is in the range of 0.05 to 0.5 mm.

(20) The drill entry sheet according to (1), wherein the metal support foil is aluminum having a purity of 95% or more.

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

(22) A method for producing a drill entry sheet by forming a layer made of a resin composition on at least one side of a metal support foil, wherein the resin composition is a polyethylene glycol (PEG) -polypropylene glycol represented by the formula (1) 3 to 30 parts by weight of a block copolymer (A) and 70 to 97 parts by weight of a water-soluble resin (B) containing polyethylene oxide (PEO), and the polyethylene glycol · polypropylene glycol · block copolymer (A ) And the water-soluble resin (B) is 100 parts by weight, the polyethylene glycol-polypropylene glycol-block copolymer (A) has a PEG / PPG ratio of 0.1 to 1 and a number average molecular weight of 1,800 to 4,000 , And the thickness of the resin composition layer is in the range of 0.02 to 0.2 mm.

(2)

(1, m, n in the formula (1) is a repetition number and is an integer of 1 or more.)

(23) A process for producing a resin composition comprising the step of coating a resin composition solution obtained by dissolving the resin composition in a solvent on at least one surface of a metal support foil, a drying step and a cooling step, 22). ≪ / RTI >

(24) The drill entry sheet according to (23), wherein the resin composition layer is formed by using a mixed solvent of water and a solvent having a lower boiling point than water as a solvent used for solution of the resin composition ≪ / RTI >

(25) A drill entry sheet according to (22), characterized in that a layer of a thermosetting resin or a thermoplastic resin is formed on at least one surface of a metal support foil in advance and a layer made of the resin composition is formed thereon Gt;

(26) The method of manufacturing a drill entry sheet according to (23), wherein the cooling step is performed at 120 to 160 deg. C for 20 to 40 deg. C for 5 to 30 seconds.

By using the drill entry sheet of the present invention, the lubricating property is excellent, so that the dischargeability of the cutting powder at the time of drilling is improved, the roughness of the hole wall is small, and the hole position accuracy is improved. As a result, it becomes possible to perform the boring process with high quality and excellent productivity.

The drill entry sheet of the present invention is a drill entry sheet for forming a layer made of a resin composition (hereinafter referred to as "resin composition layer") 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 polyethylene glycol · polypropylene glycol · block copolymer (A), and the polyethylene glycol · polypropylene glycol · block copolymer is optimized to a specific structure and molecular weight do. As a result, the lubricity of the entry sheet was increased, and the dischargeability of the chips thus cut was improved. In addition, by mixing the block copolymer in an appropriate amount, lubricity can be improved without deteriorating hole position accuracy while maintaining an austenitic property.

When the polyethylene glycol-polypropylene glycol-block copolymer is blended in the resin composition, the hole wall roughness is reduced and the hole position accuracy is improved. As the structure of the action and effect, the melting point of the copolymer is low and it is liquid at 25 占 폚. Therefore, even at the beginning of drilling drilling, that is, at low temperature of the drill bit, Lt; / RTI > As a result, the hole wall roughness is reduced. Further, since the resin composition of the drill entry sheet surrounding the drill bit melts moderately due to the frictional heat during drill drilling, the drill bit does not slip, and hole position accuracy is improved.

On the other hand, for example, linear polyethyleneglycol having a number average molecular weight of 1,800-4,000, which does not contain polypropylene glycol in the molecular structure, has a melting point higher than that of the copolymer and little effect of lowering the viscosity of the resin composition, A similar lubrication effect as in the case of blending polyethylene glycol-polypropylene glycol-block copolymer can not be obtained.

As a characteristic of the polyethylene glycol-polypropylene glycol-block copolymer molecule, there is a tendency that steric hindrance occurs easily between molecules due to the inclusion of polypropylene glycol in the molecule, and it is difficult to solidify. In addition, since the polyethylene glycol-polypropylene glycol-block copolymer is polyethylene glycol on both sides, compatibility with other resin components is improved. Therefore, the resin composition layer is uniformly formed, the sheet formability is not lowered, and defects in which the copolymer leaks out from the surface of the resin composition layer (dyeing) are suppressed. The proportion and average molecular weight of the polypropylene glycol and polyethylene glycol in the polyethylene glycol-polypropylene glycol-block copolymer molecule can be appropriately selected to improve the lubricity, sheet formability, and compatibility.

The polyethyleneglycol-polypropylene glycol-block copolymer (A) is represented by the following formula (1). That is, it is a block copolymer having a polyethylene glycol chain on both sides of the polypropylene glycol chain. The weight ratio of the polyethylene glycol and the polypropylene glycol represented by the formula (1) (hereinafter referred to as the PEG / PPG ratio) is 0.1 to 1 on the average value, preferably 0.1 to 0.9, More preferably 0.2 to 0.8, and most preferably 0.3 to 0.8. When the ratio of PEG / PPG is less than 0.1, the compatibility with the water-soluble resin (B) is poor, and it is difficult to form a uniform layer, resulting in manufacturing defects. Further, when the PEG / PPG ratio exceeds 1 in the average value, the lubricating effect becomes small. Here, the PEG / PPG ratio is the weight ratio of the ethylene glycol structural unit and the propylene glycol structural unit contained in the formula (1), and the ratio of PEG / PPG = [44 x (l + n)] / (58 x m) .

(3)

(1, m, n in the formula (1) is a repetition number and is an integer of 1 or more.)

The number average molecular weight of the polyethylene glycol-polypropylene glycol-block copolymer (A) is preferably 1,800 to 4,000, more preferably 2,000 to 4,000, and most preferably 2,500 to 4,000. If the number-average molecular weight is less than 1,800, the drill bit slips and deteriorates the percibility of the drill bit, resulting in deterioration of hole position accuracy. In addition, when the number average molecular weight is 4,000 or more, the lubricating effect is reduced and the hole wall roughness is deteriorated.

The polyethylene glycol-polypropylene glycol-block copolymer (A) is contained in an amount of 3 to 30 parts by weight, preferably 3 to 25 parts by weight, more preferably 5 to 20 parts by weight, More preferably 5 parts by weight to 15 parts by weight. If the content of the copolymer (A) is less than 3 parts by weight, the lubricating effect of the copolymer (A) does not develop. When the content of the copolymer (A) exceeds 30 parts by weight, the resin composition becomes sticky, which makes it difficult to form a sheet, resulting in manufacturing defects. Further, since the percussion property of the drill bit is deteriorated, the degree of hole position is deteriorated.

1, m and n in the structural formula (1) of the polyethylene glycol-polypropylene glycol-block copolymer (A) are integers of 1 or more, and the following ranges are obtained from the relationship between the PEG / PPG ratio and the number average molecular weight. (1 + n) is an integer of 5 to 44, and m is an integer of 16 to 61. In the case where (l + n) is 5 ≤ (l + n) ≤ 10, m is an integer between -0.7 × (1 + n) + 30.8 <m <5.8 × (1 + n) + 6.3 m + l + n) + 68.8 where m is -0.8 x (l + n) + 31.8 < m & m is an integer between 0.8 x (l + n) + 0.3 < m < -0.7 x (l + n) + 67.6 when 20? (l + n)? 44. (l + n) is less than 5, a sufficient lubrication effect is not obtained, the hole wall roughness reducing effect is small, the surface condition of the entry sheet deteriorates, and the hole position accuracy deteriorates. (1 + n) exceeds 44, the polyethylene glycol · polypropylene glycol · block copolymer (A) does not exhibit a sufficient lubricating effect, the effect of reducing the hole wall roughness is small, the resin composition is wound around the drill bit (twine), hole position accuracy is deteriorated. When m is less than the above range, a sufficient lubrication effect is not obtained, the effect of reducing the roughness of the hole wall is reduced, the surface condition of the entry sheet is deteriorated, and the hole position accuracy is deteriorated. If m exceeds the above range, a sufficient lubrication effect is not obtained, the hole wall roughness reducing effect is small, the resin composition is wound around the drill bit, and the hole position accuracy is deteriorated.

The analytical method of the polyethylene glycol-polypropylene glycol-block copolymer (A) is as follows. First, the polyethylene glycol · polypropylene glycol · block copolymer is separated and extracted from the resin composition of the drill entry sheet. The PEG / PPG ratio analysis method of the polyethylene glycol-polypropylene glycol-block copolymer is carried out by NMR measurement and is calculated from the peak area ratio. This ratio is the PEG / PPG ratio of the copolymer. The molecular weight of the polyethylene glycol-polypropylene glycol-block copolymer is measured as follows. First, the hydroxyl value of the copolymer is calculated in accordance with JIS-K-1577-1. The molecular weight obtained from the formula of number average molecular weight = 56100 ÷ hydroxyl group × 2 is the number average molecular weight of the polyethylene glycol · polypropylene glycol · block copolymer contained in the resin composition of the drill entry sheet.

The action mechanism of the polyethylene glycol · polypropylene glycol · block copolymer (A) is roughly as follows. First, in order to exhibit lubricity during drilling, it is necessary to dissolve the resin composition surrounding the drill bit sufficiently to reduce the viscosity by increasing the temperature of the drill bit during drilling. Then, it is necessary to wrap the solid cutting powder and to smoothly discharge the powder through the drill bit groove. By blending the polyethylene glycol-polypropylene glycol-block copolymer (A) into the resin composition, the solidification point can be lowered, and the resin composition product has a low viscosity at the initial stage of drilling, have.

Second, it is important to blend a polyethylene glycol · polypropylene glycol · block copolymer (A) having compatibility with the water-soluble resin (B). In order to exhibit the lubrication effect of polyethylene glycol · polypropylene glycol · block copolymer (A) to exhibit the pore wall roughness reducing effect, polyethylene glycol · polypropylene glycol · It is necessary to contain the block copolymer (A). Further, when a block copolymer having low compatibility with the water-soluble resin (B) is blended, characteristics such as hole position accuracy deteriorate. The polyethylene glycol · polypropylene glycol · block copolymer (A) is excellent in compatibility with the water-soluble resin (B) because both ends of the polyethylene glycol · polypropylene glycol · block copolymer (A) are polyethylene glycol as shown in the formula (1).

It is more preferable that the polyethylene glycol-polypropylene glycol-block copolymer (A) is appropriately selected according to the specifications of the copper-clad laminate and the multilayer plate to be drilled, the drilling processing conditions, and the like. For example, when the diameter of the drill bit is small and the thickness of the copper clad laminate is small, the roughness of the hole wall is not coarse, and when the diameter of the drill bit is large and the thickness of the copper clad laminate is thick, Therefore, it is more preferable to appropriately select the number average molecular weight, blending amount, and PEG / PPG ratio of the block copolymer within the scope of the present invention, depending on the perforation processing conditions.

The resin composition of the present invention may contain one of a water-soluble resin and a water-insoluble resin in the case of a resin composition containing a polyethylene glycol · polypropylene glycol · block copolymer (A), but it may contain a water- (B).

The water-soluble resin (B) is assumed to contain polyethylene oxide. The number average molecular weight of the polyethylene oxide is preferably 50,000 or more and 1,000,000 or less, more preferably 50,000 or more and 200,000 or less, and most preferably 50,000 or more and 100,000 or less. Polyethylene oxide having a number average molecular weight exceeding 1,000,000 is not distributed. Polyethylene oxide having a number average molecular weight of less than 50,000 may be difficult to form a sheet. The water-soluble resin (B) contains polyethylene oxide (number average molecular weight: 50,000 or more). Preferably, the water-soluble resin (B) containing polyethylene oxide is contained in an amount of 70 to 97 parts by weight, preferably 75 to 97 parts by weight, more preferably 80 to 95 parts by weight , And most preferably 85 to 95 parts by weight. If the content of the copolymer (A) is less than 3 parts by weight, the lubricating effect of the copolymer (A) does not develop. When the content of the copolymer (A) is more than 30 parts by weight, the resin composition tends to become sticky, which makes it difficult to form a sheet, resulting in manufacturing defects. Further, since the percussion property of the drill bit is impaired, the degree of hole position deteriorates.

If the content of the water-soluble resin (B) containing polyethylene oxide is less than 70 parts by weight, sheet formation is difficult and defects occur in production. Further, since the percussion property of the drill bit is deteriorated, the degree of hole position is deteriorated. If the content of the polyethylene oxide-containing water-soluble resin (B) exceeds 97 parts by weight, the melt viscosity of the resin composition increases and the tendency of the resin composition to be wound around the drill bit increases.

As the component other than polyethylene oxide, a lubricant having a number average molecular weight of 20,000 or less can be compounded. For example, one or more selected from the group consisting of polyethylene glycol, polypropylene oxide, sodium polyacrylate, polyacrylamide, polyvinylpyrrolidone, carboxymethylcellulose, and polytetramethylene glycol may be contained. In addition, a water-soluble lubricant having a number average molecular weight of 20,000 or less can be blended unless the effect of the present invention is adversely affected. For example, polypropylene glycol; Polyoxyethylene monoethers exemplified by polyoxyethylene oleyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether and polyoxyethylene octylphenyl ether ; Polyoxyethylene monostearate, polyoxyethylene sorbitan monostearate; Polyglycerin monostearates exemplified by hexaglycerin monostearate, decahexa glycerin monostearate and the like; Polyoxyethylene propylene copolymer and the like can be suitably used in combination.

The blend weight ratio (PEO / PEG) of polyethylene oxide to polyethylene glycol in the water-soluble resin (B) is preferably 0.05 to 25. The ratio is preferably from 0.05 to 20, more preferably from 0.05 to 10, still more preferably from 0.05 to 7, most preferably from 0.1 to 5. When the blending ratio of polyethylene oxide to polyethylene glycol in the water-soluble resin (B) is less than 0.05, sheet formation is difficult and defects occur in production. Further, since the percussion property of the drill bit is deteriorated, the degree of hole position is deteriorated.

In addition, the resin composition of the present invention may contain other materials to uniformly form the resin composition layer. For example, a surface modifier and a nucleating agent for making the surface of the resin composition layer uniform can be mentioned. Further, when applying the solution of the resin composition, a defoaming agent, a wettability improver, a heat stabilizer, a colorant, and the like may be blended, and any known one may be appropriately selected.

The thickness of the resin composition layer varies depending on the diameter of the drill bit used for drilling and the configuration 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 and preferably in the range of 0.02 to 0.2 mm Do. If the thickness of the resin composition layer is less than 0.02 mm, a sufficient lubrication effect can not be obtained, the effect of decreasing the roughness of the hole wall is small, and the load of the drill bit is increased, and the drill bit may be damaged. On the other hand, if the thickness of the resin composition layer exceeds 0.3 mm, the tendency of the resin composition to wrap around the drill bit may increase.

The solubility point of the water-soluble resin (B) alone is high with respect to the solidification point of the resin composition, and the combination of the polyethylene glycol · polypropylene glycol · block copolymer (A) has an effect of lowering the freezing point. By lowering the solidification point of the resin composition, the resin composition can be easily viscosed when drilling. Therefore, the resin composition exhibits a high lubrication effect and the hole wall roughness reducing effect becomes large. However, when the solidification point of the resin composition is too low, problems arise such that the layer formation rate at the time of forming the resin composition layer in the production process is lowered, or the resin composition layer is dissolved in a high temperature environment. Therefore, the solidification point of the resin composition is preferably 40 占 폚 to 44 占 폚, more preferably 41 to 44 占 폚, and even more preferably 42 to 44 占 폚. When the solidification point of the resin composition is less than 40 캜, the above-mentioned reason causes inconvenience in manufacture and storage. When the solidification point of the resin composition exceeds 44 캜, the resin composition is hardly reduced in viscosity at the time of drilling, a sufficient lubrication effect is not obtained, and the effect of reducing the hole wall roughness is reduced.

The solidification point of the resin composition is a temperature at which the resin composition changes from a liquid to a solid when the resin composition melted by heat from the outside is cooled at a constant rate. The measurement of the freezing point of this resin composition is carried out using DSC (differential scanning calorimeter, DSC6220 high-sensitivity DSC, product of SIINano technology Inc.). A sheet sample of about 10 mg is placed on an aluminum plate, and the temperature is raised from 30 캜 to 150 캜 at a rate of 3 캜 / min under a nitrogen atmosphere, and maintained at 150 캜 for 3 minutes. Further, the temperature is lowered at a rate of -3 ° C / minute from 150 ° C to 30 ° C. At this time, the temperature at the time of the peak value of the exothermic peak at the time of cooling is the freezing point of the resin composition.

As a method of forming the resin composition layer, a method of directly applying a heat dissolving material or a solution of the resin composition onto the metal supporting foil by a coating method or the like and drying the resin composition, or a method of preparing a sheet of the resin composition in advance , A method of joining with the metal supporting foil, and the like. At this time, since the resin coating is formed in advance on the metal support foil, the metal support foil and the resin composition layer can be laminated and integrated.

In the case of forming the resin composition layer by the coating method or the like, a method of dissolving the resin composition in advance in a solvent compatible with the resin composition, applying the solution directly to the metal support foil, and drying can be exemplified. When water is used as the solvent, the solution to be 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, alcohols such as ethanol, methanol and isopropyl alcohol, and low-boiling solvents such as methyl ethyl ketone and acetone can also be used . As other solvent, a solvent in which water and alcohols are partially mixed with tetrahydrofuran and acetonitrile highly compatible with the resin composition can be used.

When the solution of the resin composition is applied directly to the metal support foil by a coating method and then heated and dried, the temperature of the entry sheet is set at 120 to 160 DEG C for 5 to 30 seconds at 20 to 40 DEG C Lt; 0 &gt; C. A high drying temperature exceeding 160 占 폚 may interfere with industrial stable production, and a cooling temperature lower than 20 占 폚 may cause condensation in a subsequent step, which is not preferable.

In the case of a hot melt method in which a resin composition is dissolved by heat without forming a solution of the resin composition and a sheet is formed by extrusion molding or the like while the resin composition is made low in viscosity, It is preferable to cool from ~ 160 ° C to 20 ° C to 40 ° C in 5 to 30 seconds. A high drying temperature exceeding 160 DEG C may interfere with industrial stable production, and a cooling temperature lower than 20 DEG C 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 layer and can withstand impacts caused by a drill bit. As the metal supporting foil metal species, for example, aluminum may be used, and the thickness of the metal supporting foil is usually 0.05 to 0.5 mm, preferably 0.05 to 0.3 mm. When the thickness of the aluminum foil is less than 0.05 mm, burrs of the laminated board are liable to be generated in the drilling process. When the thickness of the aluminum foil is more than 0.5 mm, it may be difficult to discharge the chips generated in the drilling process. As the material of the aluminum foil, aluminum having a purity of 95% or more is preferable, and for example, 5052, 3004, 3003, 1N30, 1N99, 1050, 1070, 1085, 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 and the biting property with the tip of the drill bit are improved, and the lubrication effect of the drill bit by the resin composition layer The hole position accuracy of the machining hole can be increased.

From the viewpoint of adhesion between the resin composition layer and the metal foil, it is preferable to use an aluminum foil having a resin coating on the surface in advance of 0.001 to 0.02 mm in thickness. The resin used for the resin coating is not particularly limited as long as it can improve the adhesion with the water-soluble resin composition, and either thermoplastic resin or 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 epoxy resin and cyanate resin. Further, in the present invention, for the metal supporting foil, a commercially available metal foil coated with a resin by a known method may be used in advance. Among them, preferably, by using the above-mentioned thermosetting resin, it is possible to improve the bite property and the viscous property with the tip portion of the drill bit and to improve the hole position accuracy. When the thickness of the resin film is less than 0.001 mm, a sufficient adhesive force can not be obtained and the resin is wound around the drill bit, which falls on the surface of the sheet, and the hole position accuracy deteriorates. When the thickness of the resin film is more than 0.02 mm, the resin film component is wrapped around the drill bit, and in this case, the accuracy of the hole position is likewise worried.

The drill entry sheet of the present invention is used when drilling a printed wiring board material, for example, a copper-clad laminate or a multilayer board. Specifically, a copper clad laminate or a multilayer plate is placed on the uppermost surface of a laminate of one or more sheets so that the metal support foil side is in contact with the printed wiring material, and drilling processing is performed from the surface of the water-soluble resin composition of the drill entry sheet .

The foregoing is merely illustrative of an embodiment of the present invention, and various modifications may be made according to the description of the claims.

Example

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. In the present specification, "polyethylene glycol" is abbreviated as "PEG", "polypropylene glycol" is referred to as "PPG" and "polyethylene oxide" is referred to as "PEO" in the examples and comparative examples.

&Lt; Example 1 >

As shown in Table 1, 27 parts by weight of polyethylene oxide (ALTOP MG-150, manufactured by Meisei Chemical Works, Ltd.) having a number average molecular weight of 50,000 as a water-soluble resin (B) 63 parts by weight of polyethylene glycol (PEG4000S, manufactured by Sanyo Chemical Industries, Ltd.) were dissolved in a mixed solvent of 140 parts by weight of water and 93 parts by weight of MeOH (methanol). 10 parts by weight of polyoxyethylene polyoxypropylene glycol (BLAUNON P-171, product of Aoki Oil Industrial Co., Ltd.) was added to the water-soluble resin solution to completely dissolve it. Further, 0.25 parts by weight of sodium formate (manufactured by Mitsubishi Gas Chemical Company, Inc.) as an additive (C) was added to 100 parts by weight of the total of the resin composition to completely dissolve it. A solution of this water-soluble resin composition was applied on a aluminum foil (used aluminum foil: 3004, (thickness 0.12 mm) manufactured by Mitsubishi Aluminum Co., Ltd.) having an epoxy resin coating having a thickness of 0.01 mm formed on one surface thereof with a bar coater And dried so that the water-soluble resin composition layer after drying became 0.05 mm, dried at 120 ° C for 3 minutes in a drier, and then cooled to room temperature to prepare a drill entry sheet.

&Lt; Examples 2 to 12 >

A drill entry sheet was produced in accordance with Example 1 using the block copolymer shown in Table 1, the water-soluble resin (B), and the additive (C).

&Lt; Comparative Example 1 &

As shown in Table 1, 27 parts by weight of polyethylene oxide (ALTOP MG-150, manufactured by Myung Sung Kagaku Kogyo Co., Ltd.) having a number average molecular weight of 50,000 as a water-soluble resin (B) and 20 parts by weight of polyethylene glycol (PEG4000S, manufactured by Samyang Chemical Industry Co., Ltd.) Were dissolved in a mixed solvent of 140 parts by weight of water and 93 parts by weight of MeOH (methanol). Further, 10 parts by weight of polyethylene glycol-polypropylene glycol-polyethylene glycol (block copolymer) (PLONON # 104, NOF Corporation) was added to the water-soluble resin solution to completely dissolve it. Further, 0.25 parts by weight of sodium formate (manufactured by Mitsubishi Gas Chemical Company) as an additive (C) was added to 100 parts by weight of the total of the resin composition to completely dissolve it. A solution sheet of the water-soluble resin composition was prepared by the manufacturing method according to Example 1.

&Lt; Comparative Examples 2 to 14 &

Using the block copolymer shown in Table 1, the water-soluble resin (B) and the additive (C), a drill entry sheet was produced by the manufacturing method according to Comparative Example 1.

<Evaluation method>

The following evaluations were carried out on each sample of the drill entry sheet prepared in Examples and Comparative Examples.

(1) Hole position accuracy

Five copper laminated plates (CCL-HL832, copper-sided 12 μm, Mitsubishi Gas Chemical Co., Ltd.) having a thickness of 0.2 mm were stacked on top of each other with the resin composition layer of the prepared entry sheet facing up. A reinforcing board (bakelite board) was placed on the lower side of the laminated copper clad laminate to form a drill bit of 0.2 mmφ (model number: C-CFU020S manufactured by Tungaloy Corporation) Number of revolutions: 200,000 rpm , 20 drill holes were drilled at 3,000 hits per 1 drill bit under conditions of a conveying speed of 13 μm / rev. And an ascending speed of 25.4 m / min.

A hole analyzer (model number: HA-1AM, product of Hitachi Via Mechanics, Ltd.) was used to measure the difference between the position of the hole on the back surface of the lowest plate of the overlapped copper-clad laminate and the designated coordinates And a maximum value, an average value and a standard deviation (?) Were calculated for each drill bit, and "average + 3?" Was calculated. From the "average + 3?" Of 20 drill drilling processes, the average value was calculated and the results are shown in Table 1. The criteria for hole position accuracy are as follows.

medium

⊚: less than 20 μm

?: 20 占 퐉 or more and less than 25 占 퐉

?: 25 占 퐉 or more and less than 30 占 퐉

×: 30 μm or more or not sheet

Maximum value

◎: Less than 55μ

?: 55 占 퐉 or more and less than 60 占 퐉

DELTA: 60 m or more and less than 70 m

×: 70 μm or more or not sheet

(2) Hole wall roughness

Four copper laminated plates (CCL-HL830, copper-sided 12 μm, Mitsubishi Gas Chemical Co., Ltd.) having a thickness of 0.8 mm were stacked on top of each other with the resin composition layer of the prepared entry sheet facing up. A reinforcing plate (bakelite plate) was placed on the lower side of the overlapped copper-clad laminate, and a drill bit was 0.25 mmφ (model number: NEU L026W Union Tool Co.), the number of revolutions was 160,000 rpm, . 20 drill holes were drilled with 3,000 hits per conditional drill bit. The top plate of the copper clad laminate subjected to drilling was subjected to desmear treatment and plating treatment and then subjected to edge polishing on the surface passing through the center of the hole. In addition, the cross-section of the glass fiber contained in the copper-clad laminate was polished in the direction of 90 degrees. The intention is to properly evaluate the gouge of the resin, that is, the hole wall roughness. On the other hand, there is a method of grinding the cross section of the glass fiber in the 45 占 direction. It is mainly used for plating leakage, that is, for observing microcracks. When the end face is polished in the direction of 45 占 폚, the hole wall roughness becomes a small value, and therefore it is not appropriate. In the present invention, as described above, the cross-section of the glass fiber is polished in the 90 占 direction.

The inner wall of each through hole was used as a reference line, and the maximum value of the recesses was measured in a 100-fold field of view using a metallurgical microscope (Model No .: EPIPHOT200, Nikon Corporation). The measurement site was calculated from the average and maximum values of 20 points in total with 10 through holes of 3,000 hits from 2,991 hits. The criteria for hole wall roughness are as follows.

⊚: less than 10 탆

?: 10 占 퐉 or more and less than 11 占 퐉

?: 11 μm or more and less than 12 μm

×: 12 μm or more or not sheet

In the present invention, the conditions of the desmear treatment and the plating treatment of the copper clad laminate subjected to drilling are as follows. The desmear treatment was carried out at 80 캜 for 8 minutes by an etching process (using reagent: OPC-B103 manufactured by Okuno Chemical Industries Co., Ltd.) for 5 minutes at 65 캜 for 5 minutes PTH-1200NA manufactured by Okuno Pharmaceutical Co., Ltd.), and a neutralization process (product used: OPC-B303, manufactured by Okuno Pharmaceutical Co., Ltd.) for 5 minutes at 45 ° C was performed. For the plating treatment, acid degreasing (product: PB-242D, product of Ebara-Udylite Co., Ltd.) was conducted at 45 ° C for 5 minutes, and then electroless copper plating So that the thickness was 20 mu m.

(3) Comprehensive judgment

Based on the determination of hole position accuracy and hole wall roughness, comprehensive judgment is carried out. In each of the evaluation results, the lowest determination was made as the composite determination of the perforated entry sheet.

The block copolymer (A) The water-soluble resin (B) Additive (C) Amount The freezing point of the resin composition Hole Position Accuracy Hole wall roughness Bell
synthesis
plate
tablet ingredient Mn PEG / PPG ratio [Parts by weight] B-1 B-2 B-3 Average
[Mu m] Judgment maximum
[Mu m] Judgment Average
[Mu m] Judgment [Parts by weight] [Parts by weight] [Parts by weight] [Parts by weight] [° C] Example 1 A-1 1900 0.1 10 27 0 63 0.25 - 21.4 ○ 34 ◎ 10.7 ○ ○ Example 2 A-2 2220 0.1 10 27 0 63 0.25 - 22.1 ○ 44 ◎ 10.8 ○ ○ Example 3 A-3 2400 0.3 10 27 0 63 0.25 - 24.0 ○ 52 ◎ 9.8 ◎ ○ Example 4 A-4 2800 0.7 10 27 0 63 0.25 - 21.4 ○ 34 ◎ 10.7 ○ ○ Example 5 A-5 3330 0.7 10 27 0 63 0.25 42.8 18.1 ◎ 30 ◎ 8.1 ◎ ◎ Example 6 A-5 3330 0.7 3 29 0 68 0.25 43.4 19.5 ◎ 28 ◎ 10.8 ○ ○ Example 7 A-5 3330 0.7 5 29 0 66 0.25 43.5 15.7 ◎ 38 ◎ 10.4 ○ ○ Example 8 A-5 3330 0.7 7 28 0 65 0.25 43.4 16.9 ◎ 52 ◎ 10.1 ○ ○ Example 9 A-5 3330 0.7 30 21 0 49 0.25 - 20.5 ○ 34 ◎ 7.6 ◎ ○ Example 10 A-5 3330 0.7 10 9 0 81 0.25 - 17.5 ◎ 31 ◎ 10.9 ○ ○ Example 11 A-5 3330 0.7 10 68 0 22 0.25 - 23.8 ○ 54 ◎ 10.8 ○ ○ Example 12 A-5 3330 0.7 30 53 0 17 0.25 - 24.7 ○ 58 ○ 9.9 ◎ ○ Comparative Example 1 A-6 1670 0.7 10 27 0 63 0.25 44.7 42.5 × 96 × 11.4 △ × Comparative Example 2 A-7 2500 1.5 10 27 0 63 0.25 - 21.2 ○ 69 △ 12.2 × × Comparative Example 3 A-8 10000 4.0 10 27 0 63 0.25 - 14.8 ◎ 28 ◎ 12.2 × × Comparative Example 4 A-9 2000 0.3 10 27 0 63 0.25 - Not sheet × Comparative Example 5 A-10 2000 0.4 10 27 0 63 0.25 - Not sheet × Comparative Example 6 A-11 3000 - 10 27 0 63 0.25 - 17.4 ◎ 32 ◎ 11.9 △ △ Comparative Example 7 A-12 4000 - 10 27 0 63 0.25 - 34.5 × 80 × 11.5 △ × Comparative Example 8 A-13 4000 - 10 27 0 63 0.25 - 17.9 ◎ 50 ◎ 11.1 △ △ Comparative Example 9 - - - 0 30 0 70 0.25 - 19.9 ◎ 55 ○ 11.4 △ △ Comparative Example 10 A-5 3330 0.7 2 29 0 69 0.25 - 16.2 ◎ 45 ◎ 11.4 △ △ Comparative Example 11 A-5 3330 0.7 35 20 0 45 0.25 - 43.5 × 78 × 9.8 ◎ × Comparative Example 12 A-5 3330 0.7 45 17 0 38 0.25 - Not sheet × Comparative Example 13 - - - 0 0 30 70 0.25 - 24.2 ○ 35 ◎ 12.8 × × Comparative Example 14 A-5 3330 0.7 10 0 27 63 0.25 - 25.6 △ 67 △ 12.6 × ×

The block copolymer (A)

A-1: Polyoxyethylene polyoxypropylene glycol (PEG-PPG-PEG type) (BLAUNON P-171,

A-2: Polyethylene glycol-polypropylene glycol-polyethylene glycol (block copolymer) (PLONON # 201,

A-3: Polyethylene glycol-polypropylene glycol-polyethylene glycol (block copolymer) (PLONON # 202B,

A-4: Polyoxyethylene polyoxypropylene glycol (PEG-PPG-PEG type) (BLAUNON P-174,

A-5: Polyethylene glycol-polypropylene glycol-polyethylene glycol (block copolymer) (PLONON # 204,

A-6: Polyethylene glycol-polypropylene glycol-polyethylene glycol (block copolymer) (PLONON # 104,

A-7: Polyoxyethylene polyoxypropylene glycol (PEG-PPG-PEG type) (BLAUNON P-106,

A-8: Polyethylene glycol-polypropylene glycol-polyethylene glycol (block copolymer) (PLONON # 208,

A-9: Polyoxyethylene polyoxypropylene glycol (PPG-PEG-PPG type) (BLAUNON EP-0480,

A-10: Polyoxyethylene polyoxypropylene glycol (PPG-PEG-PPG type) (BLAUNON EP-0670,

A-11: polyoxytetramethylene-polyoxyethylene glycol (arbitrary type) (POLYSERIN DC-3000E, NOYU Co., Ltd.)

A-12: polyoxyethylene-monomethyl ether (UNIOX M-4000, available from Yuyo Co., Ltd.)

A-13: Polypropylene glycol (diol) (UNIOL D-4000, manufactured by NOYU Co., Ltd.)

The water-soluble resin (B)

B-1: Polyethylene oxide having a number average molecular weight of 50,000 (ALTOP MG-150 manufactured by Myung Sung Kagaku Kogyo Co., Ltd.)

B-2: Polyethylene glycol-dimethyl terephthalate polycondensate (PAOGEN PP-15, manufactured by Daiichi Kogyo Shoji Co., Ltd.) having a number average molecular weight of 50,000

B-3: Polyethylene glycol having a number average molecular weight of 3,000 (PEG4000S, manufactured by Samyang Chemical Industry Co., Ltd.)

In order to obtain a uniform resin layer surface, 0.25 parts by weight of sodium formate (Mitsubishi Gas Chemical Co., Ltd.) was added as an additive (C) to 100 parts by weight of the water-soluble resin (B).

Drilling process conditions

(1) Hole position accuracy Evaluation condition: Drill diameter: 0.2 mmφ (Model number: C-CFU020S manufactured by Tungalloy Co.), Machining base: HL832 0.2 mmt Cu12 μ 5 ply (Mitsubishi Gas Chemical Co., : 13 [mu] m / rev. Ascent rate: 25.4m / min. 20 drill holes were drilled with 3,000 hits per drill bit.

(2) Hole wall roughness Evaluation conditions: Drill diameter: 0.25 mmφ (Model number: NEU L026W Union Tool Co., Ltd.), Machining base: HL830 0.8 mmt Cu12 mu 4 ply (Mitsubishi Gas Chemical Co., 14 [mu] m / rev. Ascent rate: 25.4m / min. 20 drill holes were drilled with 3,000 hits per drill bit.

From the results shown in Table 1, it was found that the samples of Examples 1 to 12 had smaller hole wall roughness and higher hole position accuracy than the samples of Comparative Examples 1 to 14.

According to the present invention, it is possible to provide a drill entry sheet having a small hole wall roughness and an excellent hole position accuracy as compared with a conventional drill entry sheet.

Claims (26)

A drill entry sheet having a layer of a resin composition formed on at least one side of a metal support foil,
3 to 30 parts by weight of a polyethylene glycol (PEG) -Polypropylene glycol (PPG) -block copolymer (A) represented by the formula (1)
And 70 to 97 parts by weight of a water-soluble resin (B) containing polyethylene oxide (PEO)
The total of the polyethylene glycol-polypropylene glycol-block copolymer (A) and the water-soluble resin (B) is 100 parts by weight,
The polyethylene glycol-polypropylene glycol-block copolymer (A) has a PEG / PPG ratio of 0.1 to 1, a number average molecular weight of 1,800 to 4,000,
Wherein the thickness of the resin composition layer is in the range of 0.02 to 0.2 mm.

(1, m, n in the formula (1) is a repetition number and is an integer of 1 or more.)
The method according to claim 1,
Wherein the content of the polyethylene glycol (PEG) polypropylene glycol (PPG) block copolymer (A) is 5 to 15 parts by weight.
The method according to claim 1,
Wherein the polyethylene glycol-polypropylene glycol-block copolymer (A) has a PEG / PPG ratio of 0.1 or more and less than 0.3, and a number average molecular weight of 1,900 or more and 2,200 or less.
The method according to claim 1,
Wherein the polyethylene glycol-polypropylene glycol-block copolymer (A) has a PEG / PPG ratio of 0.1 or more and less than 0.3, and a number average molecular weight of not less than 2,220 and less than 2,400.
The method according to claim 1,
Wherein the polyethylene glycol-polypropylene glycol-block copolymer (A) has a PEG / PPG ratio of 0.3 or more and less than 0.7, and a number average molecular weight of 2,400 or more to 2,800 or less.
The method according to claim 1,
Wherein the polyethylene glycol-polypropylene glycol-block copolymer (A) has a PEG / PPG ratio of from 0.7 to 1, and a number average molecular weight of from 2,800 to less than 3,330.
The method according to claim 1,
Wherein the polyethylene glycol-polypropylene glycol-block copolymer (A) has a PEG / PPG ratio of 0.7 to 1, and a number average molecular weight of 3,330 to 4,000.
The method according to claim 1,
Wherein the number average molecular weight of the polyethylene oxide contained in the water-soluble resin (B) is 50,000 or more and 1,000,000 or less.
The method according to claim 1,
Wherein the blending amount of the polyethylene oxide contained in the water-soluble resin (B) in the total of 100 parts by weight of the polyethylene glycol-polypropylene glycol-block copolymer (A) and the water-soluble resin (B) is 5 to 70 parts by weight Drill entry sheet.
The method according to claim 1,
Wherein the water-soluble resin (B) contains polyethylene glycol (PEG) having a number average molecular weight of 20,000 or less.
The method according to claim 1,
Wherein the blending amount of polyethylene glycol contained in the water-soluble resin (B) in the total of 100 parts by weight of the polyethylene glycol-polypropylene glycol-block copolymer (A) and the water-soluble resin (B) is 10 to 90 parts by weight Drill entry sheet.
The method according to claim 1,
Wherein the resin composition comprises 3 to 30 parts by weight of the polyethylene glycol-polypropylene glycol-block copolymer (A), 5 to 50 parts by weight of a polyethylene oxide having a number average molecular weight of 50,000 or more as a water-soluble resin (B) And 20 to 92 parts by weight of glycol.
The method according to claim 1,
Wherein the resin composition has a freezing point of 40 占 폚 or more and 44 占 폚 or less.
The method according to claim 1,
Characterized in that a resin composition layer is formed through a coating step, a drying step and a cooling step in which a resin composition solution obtained by dissolving the resin composition in a solvent is applied to at least one side of the metal support foil.
15. The method of claim 14,
Wherein a resin composition layer is formed by using a mixed solvent of water and a solvent having a lower boiling point than water as a solvent used for solution of the resin composition.
The method according to claim 1,
Wherein a layer of a thermosetting resin or a thermoplastic resin is formed on at least one side of the metal support foil in advance and a layer made of the resin composition is formed thereon.
17. The method of claim 16,
Wherein a thickness of the thermosetting resin or thermoplastic resin layer is 0.001 to 0.02 mm.
15. The method of claim 14,
Wherein the cooling step is carried out at a cooling rate of 120 ° C to 160 ° C to 20 ° C to 40 ° C for 5 to 30 seconds.
The method according to claim 1,
Wherein the thickness of the metal support foil is in the range of 0.05 to 0.5 mm.
The method according to claim 1,
Wherein the metal support foil is aluminum having a purity of 95% or more.
The method according to claim 1,
A drill entry sheet characterized by being used for machining a copper clad laminate or a multilayer plate.
A method for producing a drill entry sheet by forming a layer of a resin composition on at least one side of a metal support foil,
A step of applying a resin composition solution obtained by dissolving the resin composition in a solvent on at least one side of a metal support foil, a drying step and a cooling step to form a layer made of the resin composition,
3 to 30 parts by weight of a polyethylene glycol (PEG) -Polypropylene glycol (PPG) -block copolymer (A) represented by the formula (1)
And 70 to 97 parts by weight of a water-soluble resin (B) containing polyethylene oxide (PEO)
The total of the polyethylene glycol-polypropylene glycol-block copolymer (A) and the water-soluble resin (B) is 100 parts by weight,
The polyethylene glycol-polypropylene glycol-block copolymer (A) has a PEG / PPG ratio of 0.1 to 1, a number average molecular weight of 1,800 to 4,000,
Wherein the thickness of the resin composition layer is in the range of 0.02 to 0.2 mm.

(1, m, n in the formula (1) is a repetition number and is an integer of 1 or more.)
delete 23. The method of claim 22,
Wherein a resin composition layer is formed by using a mixed solvent of water and a solvent having a lower boiling point than water as a solvent used for solutioning the resin composition.
23. The method of claim 22,
Wherein a layer of a thermosetting resin or a thermoplastic resin is previously formed on at least one surface of the metal support foil and a layer made of the resin composition is formed thereon.
23. The method of claim 22,
Wherein the cooling step is carried out at a cooling rate of 120 ° C to 160 ° C to 20 ° C to 40 ° C for 5 to 30 seconds.