JP2013018066A - Stiffening plate for drilling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of moisture-resistant adhesion which results in the partial peeling of a lubricating layer 4 because of an effect of ambient humidity as to a stiffening plate 1 provided with the lubricating layer 4 via an undercoated layer 3 at one side of an aluminum substrate 2, concerning a stiffening plate for drilling used for forming a small-diameter through-hole in a raw board for a printed circuit board, for instance.SOLUTION: The undercoated layer 3 which includes a mixed resin composition containing a partially saponified substance of polyvinyl acetate as a major component and having an appropriate additive amount of an alkyl ester unsaturated carboxylic acid in order to give a moisture-resistant property is formed at least one side of the aluminum substrate 2. Then, the lubricating layer 4 including a polyethylene glycol resin and the like having a lubricative property is formed on the undercoated layer 3.

Description

  The present invention relates to a punching contact plate used when a small-diameter through hole is formed in a workpiece, such as a through hole in a printed wiring board, by drilling.

  In this specification and claims, the term “aluminum” is used to include pure aluminum and aluminum alloys. In this specification and claims, the term “plate” is used to include foil.

  Conventionally, when drilling through holes in a printed wiring board, multiple printed wiring boards are stacked on the top board, and an aluminum pad is placed on the top surface of the top board. In this state, a method is used in which through holes are formed in all the stacked substrates at once by drilling holes in the substrate for printed wiring by drilling through the corresponding plate from above with a drill. This backing plate is used for the purpose of improving the biting of the drill and preventing the occurrence of damage during processing of the surface of the base plate and the generation of burrs at the periphery of the hole.

  By the way, in recent years, with the increase in the density of printed wiring boards, it is required to form holes having a small hole diameter of 0.3 mm or less. In order to meet such demands, when a drilling process is performed with a small diameter drill having a diameter of 0.3 mm or less using a simple aluminum plate, the drill slides on the surface of the patch plate. The positional accuracy deteriorates, the drill breaks frequently, and the inner peripheral surface of the hole becomes rough. In addition, there is a problem that the number of stacked printed wiring boards cannot be increased for suppressing breakage of the drill, and the processing efficiency cannot be sufficiently increased.

  Therefore, it has been proposed that a water-soluble lubricating layer is provided on at least one surface of an aluminum substrate as a punching plate. For example, in Patent Document 1, a water-soluble lubricant sheet having a thickness of 0.1 to 3 mm made of a mixture of 20 to 90% by weight of polyethylene glycol having a molecular weight of 10,000 or more and 80 to 10% by weight of a water-soluble lubricant is arranged. It has been proposed to use.

  However, in a backing plate provided with a lubrication layer as described in Patent Document 1, adhesion between the aluminum substrate and the lubrication layer is generally poor, and the lubrication layer is partially peeled from the substrate, and the lubrication layer Inconsistency in the thickness of the surface or unevenness on the surface facing the base plate during drilling, resulting in drill breakage and reduced position accuracy of small-diameter holes was there.

  In order to improve the adhesion between the aluminum substrate and the lubricating layer as described in the following Patent Document 2, the present applicants have already dealt with such a problem with a portion of polyvinyl acetate on at least one surface of the substrate. It has been proposed to form a lubricating layer through a saponified undercoat layer. The technology according to this prior proposal improves the adhesion between the aluminum substrate and the lubricating layer as the intended purpose, contributes to the improvement of the lubricating performance, and the undercoat layer is water-soluble and easily used with water or warm water. It possessed the desirable property of being removable.

  However, when stored and used in environments with different temperature and humidity depending on the season or region, the adhesion of the undercoat layer itself to the substrate due to the humidity is particularly significant, especially when the environmental humidity is high. As a result, it has been found that there is a problem that the lubricant layer may be partially peeled off, which has been regarded as a problem in the past.

JP-A-4-92494 JP 2008-55598 A

  The present invention addresses the above-described further problem of the prior proposed technique of Patent Document 2, that is, the problem that the adhesion between the undercoat layer and the substrate and / or the lubricating layer decreases due to the influence of environmental humidity. In order to solve this problem and maintain the above-mentioned adhesion well, to prevent unintentional partial peeling of the lubricating layer, it is possible to perform a highly efficient and highly accurate drilling process, and an undercoat layer An object of the present invention is to provide a punching plate that does not lose the property of being easily removable with water or hot water.

  In order to achieve the above object, the present invention provides the following means.

[1] In a punching patch plate in which a lubricating layer is formed on at least one surface of an aluminum substrate via an undercoat layer,
A base plate for drilling, wherein the undercoat layer is made of a mixed resin composition containing a partially saponified product of polyvinyl acetate and an alkyl ester unsaturated carboxylic acid copolymer added thereto.

  [2] The punching plate according to [1], wherein the polyvinyl acetate partially saponified product has a saponification degree of 15 to 70 mol% and an average molecular weight of 9000 to 100,000.

  [3] The blending ratio of the mixed resin composition forming the undercoat layer is 85 to 99.5% by weight of partially saponified polyvinyl acetate and 0.5 to 15% by weight of alkyl ester unsaturated carboxylic acid copolymer. The punching plate according to [1] or [2] above.

  As described in the above item [1], the perforating plate according to the present invention has a lubrication layer on at least one surface of an aluminum substrate via an undercoat layer containing a partially saponified polyvinyl acetate as a main component. The above-mentioned undercoat layer is originally provided so that the undercoat layer can improve the adhesion of the lubricating layer to the base material layer and prevent its peeling in the same manner as the prior art of Patent Document 2. An alkyl unsaturated carboxylic acid copolymer is added, and the undercoat layer is composed of a mixed resin composition of a partially saponified polyvinyl acetate and the above alkyl unsaturated carboxylic acid copolymer. Thus, the lowering of the adhesion due to the influence of environmental humidity can be prevented or at least significantly reduced by the action of the additive component.

  Therefore, even when stored or used in a high-humidity environment and stored for a long time even in a normal temperature and normal humidity environment, the adhesion of the lubricating layer can be maintained stably and satisfactorily. As a result, it is possible to prevent the above-mentioned troubles due to the partial peeling, and to perform drilling with a small-diameter hole with high efficiency and high accuracy.

  Further, as described in the above item [2], a partially saponified polyvinyl acetate which is a main component of the undercoat layer has a saponification degree of 15 to 70 mol% and an average molecular weight of 9000 to 100,000. As a result, the above-described improvement or improvement in adhesion can be achieved best.

  Furthermore, as described in the above item [3], as a blending ratio of the mixed resin composition for forming an undercoat layer, 85 to 99.5 wt% of partially saponified polyvinyl acetate, alkyl ester unsaturated carboxylic acid By setting the copolymer in the range of 0.5 to 15% by weight, both the above-mentioned adhesive improvement effect and the moisture resistance improvement effect that prevents the deterioration of the adhesion due to the influence of environmental humidity are in good harmony. It can be achieved and enjoyed originally.

It is an expanded sectional view of the caulking plate according to a preferred embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows an embodiment of a base plate (1) for drilling with a small hole diameter according to the present invention. The corresponding plate (1) is an undercoat on one side of an aluminum substrate (2). The lubricating layer (4) is provided via the layer (3).

  The material of the base plate (1) made of aluminum is not particularly limited. For example, it is made of AA1100-H18 material, AA1050-H18 material, AA3003-H18 material, AA3004-H18 material, or the like. Made of a single aluminum plate. Further, Al 99.30% by weight or more, the total content of Si and Fe is 0.7% by weight or less, Cu content 0.10% by weight or less, Mn content 0.05% by weight or less, Mg content 0 An H18 material of an alloy (for example, JIS A1N30) having a Zn content of 0.05% by weight or less and a Zn content of 0.05% by weight or less can also be suitably used. In addition, it is preferable that the thickness of a board | substrate (2) is about 0.1-0.25 mm. As the substrate (2), a soft aluminum plate having a thickness of 5 to 100 μm having a Vickers hardness of 20 to 50 and a hard aluminum plate having a thickness of 30 to 200 μm having a Vickers hardness of 50 to 140 are attached. A combination of these may be used. In this case, the lubricating layer (4) is formed on the surface of the hard aluminum plate via the undercoat layer (3).

  The undercoat layer (3) contains a partially saponified product of polyvinyl acetate as a main component, and is composed of a mixed composition of the main component and an alkyl ester unsaturated carboxylic acid copolymer.

  The partially saponified product of polyvinyl acetate has the property of improving the adhesion of the lubricating layer (4) to the aluminum substrate (2), preferably has an average molecular weight of 9000 to 100,000, more preferably 10,000 to 50,000, The saponification degree is 15 to 70 mol%, more preferably 20 to 50 mol%. If the average molecular weight is less than 9000, the effect of improving the adhesion of the lubricating layer to the substrate cannot be obtained, and if it exceeds 100,000, the adhesion of the lubricating layer to the substrate is improved, but the viscosity becomes high and the lubricity is lowered. In addition, the partially saponified polyvinyl acetate used has a water solubility of less than 15 mol% and cannot be easily washed by water washing after drilling. If it exceeds 50%, the lubricity is lowered.

  Further, the alkyl ester unsaturated carboxylic acid copolymer added to and contained in the undercoat layer (3) improves the moisture-resistant adhesion of the undercoat layer (3), and can be used for the alkyl ester unsaturated carboxylic acid. Copolymers include alkyl vinyl ethers such as methyl, ethyl, propyl, isopropyl, butyl, and isobutyl, maleic acid, phthalic acid, itaconic acid, citraconic acid, acrylic acid, methacrylic acid, and derivatives thereof (anhydrides, salts, esters). Etc.). Of these, methyl vinyl ether maleic acid copolymer, ethyl vinyl ether maleic acid copolymer, methyl vinyl ether phthalic acid copolymer, and methyl vinyl ether acrylic acid copolymer are preferable.

  The weight average molecular weight of the alkyl ester unsaturated carboxylic acid copolymer can be appropriately selected, but is preferably 50,000 to 2,500,000, and more preferably 100,000 to 500,000.

  If the weight average molecular weight is less than 50,000, the adhesion to the lubricating layer may be hindered. If the weight average molecular weight is more than 2.5 million, improvement in moisture resistance adhesion cannot be expected.

  As a mixing ratio of the partially saponified product of polyvinyl acetate and the alkyl ester unsaturated carboxylic acid copolymer in the mixed resin composition forming the undercoat layer (3), the partially saponified product of polyvinyl acetate is 85 to 99.99. It is recommended that it be 5% by weight, preferably 90-98% by weight, more preferably 92-96% by weight, with the balance being an alkyl ester unsaturated carboxylic acid copolymer. That is, the blending amount of the alkyl ester unsaturated carboxylic acid copolymer is 0.5 to 15% by weight, preferably 2 to 10% by weight, more preferably 4 to 8% by weight, based on the total amount of the mixed resin composition. % Is desirable.

  If the blending amount of the alkyl ester unsaturated carboxylic acid copolymer exceeds 15% by weight, the adhesion with the lubricating resin layer may be lowered. If it is less than 0.5% by weight, the effect of preventing adhesion deterioration under high humidity cannot be sufficiently obtained.

  The heat of the undercoat layer (3) is preferably 0.1 to 10.0 μm. Especially preferably, it is 0.3-5.0 micrometers.

  The undercoat layer (3) is formed by applying a solution obtained by dissolving the mixed resin composition for undercoat in a solvent such as methanol by a known coating method such as a gravure coating method and then forcibly drying by heating. Is preferred. At this time, by setting the drying temperature to 150 ° C. or higher, preferably 170 ° C. or higher, the moisture resistance adhesion of the undercoat layer can be most effectively improved. The optimum drying temperature varies depending on the drying time, but is preferably 150 ° C. to 230 ° C., more preferably 170 ° C. to 220 ° C. at a drying time of 10 to 180 sec at a general processing speed. If sufficient drying and heat treatment are not performed, the effect of improving the moisture resistance adhesion of the undercoat layer may not be sufficiently obtained.

  The lubricating layer (4) is not particularly limited as long as it is a water-soluble lubricating resin, but preferably includes a polyethylene glycol resin, a water-soluble polyurethane resin, a polyether resin, a water-soluble polyester resin, and the like. Those in which components having different molecular weights are blended or those having a low molecular weight are blended to improve the lubricating performance can be used.

  As an example of a specific preferable lubricating resin layer (4), as shown in the examples described later, 48% by weight of polyethylene glycol having a number average molecular weight of 100,000, 47% by weight of polyethylene glycol having a molecular weight of 10,000, and polyethylene glycol having a molecular weight of 200 A resin composition comprising 5% can be mentioned. Its thickness is 10-200 μm.

  When drilling a printed wiring board base plate using the above-described backing plate (1), first, a plurality of printed wiring board base plates stacked on top of each other are placed. Next, the backing plate (1) is arranged on the uppermost base plate so that the substrate (2) faces down, that is, the base plate side, and the lubricating layer (4) faces up. In this state, through holes are formed in the counter plate (1) from above by a drill bit of the drill, and small diameter holes (not shown) are formed in all the base plates. Thus, small holes used for through holes and the like are formed in all the base plates in a single operation.

  Generation of burrs can be prevented by the function of the substrate (2) during the drilling. Further, by preventing the generation of burrs, the number of base plates to be overlapped at the time of a single drilling process can be increased, and productivity can be increased. Moreover, by preventing the generation of burrs, it becomes possible to prevent damage to the metal layer of the printed wiring board manufactured from the base plate, and to prevent disconnection of the circuit of the obtained printed wiring board. Can do.

  Next, specific examples of the present invention will be shown in comparison with comparative examples.

[Example 1]
A partially saponified product of polyvinyl acetate (trade name “SMR”, manufactured by Shin-Etsu Chemical Co., Ltd.) having an average molecular weight of 38000 and a saponification degree of 35 mol% on one side of a 150 μm thick aluminum substrate made of AA3004-H18 material. A mixed resin composition for undercoating added with 1% by weight of a methyl vinyl ether maleic acid copolymer (weight average molecular weight of about 200,000) in a solid content ratio is applied and dried to form an undercoating layer having a thickness of 1.5 μm did. Said application | coating was performed using the roll coater, and drying was performed on 200 degreeC x 60 second heating conditions.

  Next, a lubricating resin composition comprising 48% by weight of polyethylene glycol (PEG) having a number average molecular weight of 100,000, 47% by weight of PEG having a number average molecular weight of 10,000, and 5% by weight of PEG having a number average molecular weight of 200 is used on the undercoat layer. Then, a backing plate was produced by forming a lubricating layer so as to have a thickness of 80 μm.

[Example 2]
A backing plate was prepared in the same manner as in Example 1 except that a mixed resin composition for undercoating added with 4% by weight of methyl vinyl ether maleic acid copolymer was used.

[Example 3]
A patch plate was produced in the same manner as in Example 1 except that a mixed resin composition for undercoating added with 8% by weight of methyl vinyl ether maleic acid copolymer was used.

[Example 4]
A backing plate was prepared in the same manner as in Example 1 except that a mixed resin composition for undercoating added with 12% by weight of methyl vinyl ether maleic acid copolymer was used.

[Comparative Example 1]
A patch plate was prepared in the same manner as in Example 1 except that a saponified product of polyvinyl acetate without addition of methyl vinyl ether maleic acid copolymer was used as the undercoat resin.

[Comparative Example 2]
A patch plate was prepared in the same manner as in Example 1 except that a mixed resin composition for undercoating added with 17% by weight of methyl vinyl ether maleic acid copolymer was used.

[Evaluation test]
About each sample of the said Examples 1-4 and Comparative Examples 1-2, the following "moisture-resistant adhesion evaluation test of undercoat layer and aluminum substrate" and "adhesion evaluation test between undercoat layer and lubricating layer" Went.

<Humidity-resistant adhesion evaluation test between undercoat layer and aluminum substrate>
In the production process of each sample of Examples 1 to 4 and Comparative Examples 1 and 2, using the intermediate product after forming the undercoat layer and before applying the lubricating resin composition as a sample, water vapor was applied to the undercoat layer for 20 seconds. After the contact, a peel test of the undercoat layer using an adhesive tape (trade name, cellophane tape) was performed. That is, after the pressure-sensitive adhesive tape was pressed against the surface of the undercoat layer, it was visually inspected whether or not the undercoat layer was peeled off when it was slowly peeled off.

<Adhesion evaluation test between undercoat layer and lubricating layer>
For each of the samples of Examples 1 to 4 and Comparative Examples 1 to 2, a 4 mm × 4 mm grid cut was made in the lubricating layer on the surface of the backing plate, and then the lubricating layer was peeled off using an adhesive tape as described above An evaluation test was conducted.

  The results of the above evaluation tests are shown in Table 1 below.

  As can be seen from the results of the adhesion evaluation test shown in Table 1, according to the punching plate of the present invention, the resistance of the undercoat layer is increased by the action of the alkyl ester unsaturated carboxylic acid copolymer added to the undercoat layer. Humidity adhesion can be improved and peeling from the substrate in a high-humidity environment can be prevented, and by adding an appropriate amount thereof, adhesion to the lubricating layer can be maintained well without loss.

  Therefore, it is possible to prevent unintentional partial peeling of the lubricating layer even in a high humidity environment, and in turn, to prevent the occurrence of troubles during drilling such as drill breakage as described above, improving the drilling efficiency. The drilling accuracy can be improved.

DESCRIPTION OF SYMBOLS 1 ... Drilling plate 2 ... Aluminum substrate 3 ... Undercoat layer 4 ... Lubrication layer

Claims (3)

In the punching plate in which the lubricating layer is formed on at least one surface of the aluminum substrate via the undercoat layer,
A base plate for drilling, wherein the undercoat layer is made of a mixed resin composition containing a partially saponified product of polyvinyl acetate and an alkyl ester unsaturated carboxylic acid copolymer added thereto.   2. The punching plate according to claim 1, wherein the partially saponified product of polyvinyl acetate has a saponification degree of 15 to 70 mol% and an average molecular weight of 9000 to 100,000. The blending ratio of the mixed resin composition forming the undercoat layer is 85 to 99.5% by weight of partially saponified polyvinyl acetate and 0.5 to 15% by weight of alkyl ester unsaturated carboxylic acid copolymer. 3. A punching plate according to 1 or 2.

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