JP2006272671A - Composite laminated sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite laminated sheet A which enables the inner surface of its through hole to be formed smoothly, when the hole is drilled and thus, can secure high reliability in terms of continuity. <P>SOLUTION: This composite laminated sheet A can be obtained by laminating a single piece or a plurality of pieces of unwoven fabric 2 impregnated with a resin wax, then laminating a resin wax-impregnated woven fabric 1 on both surfaces of the laminate and thermally curing the laminate. In addition, a filler added to the resin wax is warastnite of not less than 95% purity. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a composite laminate used in the electric / electronic field.

  Conventionally, composite laminates have been used as one of laminates used for manufacturing printed wiring boards and the like. This composite laminate is made by laminating one or a plurality of thermosetting resin varnishes impregnated into a nonwoven fabric such as glass mat or glass paper, and the thermosetting resin varnish is laminated on both surfaces of the laminate, such as glass cloth. It is obtained by laminating what is impregnated into a woven fabric and then heat-curing (see Patent Document 1).

In the case of producing a printed wiring board using such a composite laminated board, conventionally, the punching process for forming a through hole is mainly performed, and the drilling process is also performed depending on the use application. However, in recent years, there has been a demand for composite laminates that can be punched and that can also drill fine holes.
Japanese Patent Laid-Open No. 9-09322

  However, when the nonwoven fabric is impregnated with the resin varnish, the nonwoven fabric itself is a collection of non-uniform fibers, and when the nonwoven fabric is impregnated with a resin varnish containing a filler, the fibers and the filler are irregularly assembled. A non-uniform layer is formed. Therefore, if drilling is performed on such a non-uniform layer by drilling, the weak portion is excessively cut and the strong portion tends to remain, and the inner surface of the hole to be drilled Concavities and convexities are likely to be formed on the surface, and when the through hole is formed by applying hole plating to the inner surface of such a hole, the conduction reliability may be lowered.

  The present invention has been made in view of the above points, and when drilling is performed, the inner surface of the hole can be formed smoothly and has high conduction reliability when forming a through hole. It aims at providing the composite laminated board which can ensure property.

  The composite laminate A according to the present invention is obtained by laminating one or a plurality of nonwoven fabrics 2 impregnated with a resin varnish, laminating a woven fabric 1 impregnated with a resin varnish on both sides of the laminate, and then heat-curing the laminate. The resulting composite laminate A is characterized in that the filler contained in the resin varnish is wollastonite having a purity of 95% or more.

If it does in this way, generation | occurrence | production of the unevenness | corrugation of the inner surface of the hole formed when drilling with respect to the laminated board A can be suppressed and it can be made smooth, The moisture content of the said filler is 0.1 weight% or less In this case, gas generation during heating is suppressed, and deterioration of the quality of the laminate A during heating can be prevented.

  Moreover, it is preferable that pH of the said filler is 7 or more, In this case, the alkali resistance of the laminated board A can be improved.

  Moreover, it is preferable that content in the resin varnish of the said filler is the range of 10 weight% or more and less than 60 weight% with respect to the resin varnish whole quantity. In this range, the drillability of the laminate A can be greatly improved.

  Further, the amount of magnetization of the filler is preferably 0.05% by weight or less, whereby the migration resistance of the laminate A can be improved.

  The filler preferably has an average particle size of 30 μm or less. In this case, the wear of the drill when drilling the laminated plate A can be suppressed, the drill replacement frequency can be reduced, and the productivity can be improved.

  The filler may be fibrous. In this case, generation of cracks is suppressed even when the punching process is performed on the laminated plate A, and high punching processability can be maintained.

  According to the present invention, since the inner surface of the hole to be formed becomes smooth even if drilling for forming the through hole is performed by drilling, the inner surface of the hole is plated with holes to form the through hole. When formed, this through hole can be provided with high conduction reliability.

  Hereinafter, the best mode for carrying out the present invention will be described.

  The composite laminate A of the present invention (hereinafter sometimes referred to as “laminate A”) is obtained by laminating one or a plurality of nonwoven fabrics 2 impregnated with a resin varnish, and placing resin varnish on both sides of the laminated laminate. The impregnated woven fabric 1 is laminated, and if necessary, a metal foil 6 is disposed on at least one outermost layer thereof, and then heated and cured.

  Although it does not specifically limit as the nonwoven fabric 2, The paper which uses fibers, such as glass fiber, an aramid fiber, a polyester fiber, and a nylon fiber, is mentioned. The woven fabric 1 is not particularly limited, and examples thereof include cloth using fibers such as glass fiber, aramid fiber, polyester fiber, and nylon fiber. In particular, when the nonwoven fabric 2 is a glass fiber paper (glass paper) and the woven fabric 1 is a glass fiber cloth (glass cloth), it is excellent in heat resistance and moisture resistance, which is preferable.

  Moreover, as resin contained in the resin varnish used by this invention, a radical polymerization type thermosetting resin is preferable. Examples thereof include single resins such as unsaturated polyester resins and vinyl ester resins, modified products, and mixtures. In addition to the radical polymerization type thermosetting resin, the resin varnish may optionally contain a radical polymerizable monomer such as styrene or diallyl phthalate, a filler anti-settling agent, and the like. When this resin varnish is degassed under reduced pressure, even if the amount of resin impregnated in the woven fabric 1 or the nonwoven fabric 2 is reduced, it is preferable that bubbles remaining in the laminate A are not easily generated.

In the present invention, the resin varnish contains a filler made of wollastonite, and the filler contains Al ₂ O ₃ , Fe ₂ O ₃ , MgO, K ₂ O, Na. Impurities such as ₂ O and TiO ₂ may be mixed, but the amount of such impurities mixed is 5 wt% or less, that is, a purity of 95 wt% or more is used.

Moreover, it is preferable that calcite (CaCO ₃ ) is not mixed as an impurity in the filler, and even if it is mixed, the mixed amount is preferably 1% by weight or less. In such a case, an increase in the viscosity of the resin varnish can be suppressed and the impregnation property of the resin varnish with respect to the substrate can be improved, and thus the productivity of the laminate A can be improved.

  The moisture content of the filler is desirably 0.1% by weight or less. In this case, gas generation during heating is suppressed, and deterioration in quality during heating can be prevented.

  The filler preferably has a loss on ignition (Ig. Loss) of 2% by weight or less. This ignition loss is based on JIS M8853. After 5 g of a sample is placed in a porcelain crucible, heat-treated at 800 ° C. for 1 hour, and then allowed to cool in a desiccator. It is obtained by deriving the weight loss rate of. Also in this case, generation of gas during heating is suppressed, and quality deterioration during heating can be further prevented.

Moreover, it is preferable that pH of said filler is 7 or more. In this case, the alkali resistance of the resulting laminate A can be improved. The pH of this filler is in accordance with JIS K5101, and ion-exchanged water or 40 cm ^{3 of} pure water and 10 g of a sample are put into a beaker having a volume of 100 cm ³ , stirred for 1 minute with a glass rod, and allowed to stand for 5 minutes. It can be derived by immersing the electrode of the pH meter and holding it for 1 minute and then reading the pH meter. At this time, the upper limit of the pH of the filler is not particularly limited, but the pH is desirably 12 or less in order to prevent deterioration of acid resistance.

  Moreover, it is preferable that content of the said filler is the range of 10 weight% or more and less than 60 weight% with respect to the resin varnish whole quantity, In this range, the drill workability of the laminated board A formed is improved greatly. It is something that can be done.

  Moreover, it is preferable to use a filler having a magnetization amount of 0.05% by weight or less. If it does in this way, the migration resistance of the laminated sheet A to be formed can be improved. This amount of magnetization is obtained when a 300 g sample is put in 2 L of water in a container such as a beaker and stirred for 1 minute, and a wrapping around a 10000 gauss magnet is placed in the container and stirred for 1 minute and then taken out. , It is derived by measuring the adhesion amount adhering to the magnet.

  Moreover, as such a filler, it is preferable to use a filler having an average particle diameter (D50; median diameter) of 30 μm or less. If it does in this way, wear of a drill at the time of performing drill processing to laminated board A formed can be controlled, the exchange frequency of a drill can be reduced, and productivity can be improved. The lower limit of the average particle diameter of the filler is not particularly limited, but is preferably 10 μm or more in order to suppress drill wear and maintain good punching workability.

  Further, a fibrous material may be used as the filler. In this way, the laminate A to be formed not only has excellent drillability, but also suppresses the occurrence of cracks when drilling is performed in punching, and maintains high punchability. It can be done.

  Moreover, when using metal foil 6, although it does not specifically limit, copper foil, nickel foil, etc. can be used. Moreover, it may replace with the metal foil 6 on the surface which does not arrange | position the metal foil 6, and may manufacture the laminated sheet A by arrange | positioning a release film.

  Moreover, when using the metal foil 6, the appropriate thing used for formation of the laminated board A can be used, For example, a copper foil etc. can be used.

  Laminate A can be produced using an appropriate method, but one or a plurality of nonwoven fabrics 2 continuously impregnated with resin varnish are laminated, and resin varnish is continuously applied to both sides of the laminated laminate. If the continuous construction method of laminating the woven fabric 1 impregnated impregnated and further arranging the metal foil 6 on at least one of the outermost layers as necessary and then performing continuous heat curing is adopted, Manufacturing efficiency can be improved.

  FIG. 1 shows an example of a horizontal continuous construction method. Each nonwoven fabric is passed through an impregnation apparatus 3 for supplying a resin varnish while continuously unwinding and feeding a plurality of long nonwoven fabrics 2 from a roll. 2 is impregnated with a resin varnish, and is passed through an impregnation apparatus 4 for supplying a resin varnish while continuously unwinding and feeding the long woven fabric 1 disposed above and below the roll, The woven fabric 1 is impregnated with a resin varnish. Next, the nonwoven fabric 2 impregnated with these resin varnishes and the woven fabric 1 are continuously fed while passing between the pair of laminate rolls 5 to overlap the plurality of nonwoven fabrics 2 and to put the woven fabric 1 on and under them respectively. Overlapping. At this time, the metal foil 6 (or release film) such as a long copper foil is unwound from the roll and supplied while being continuously fed to the laminating roll 5, and the metal foil 6 (or the outer surface of the upper and lower woven fabric 1 is applied to each outer surface. Release film). Then, the resin varnish impregnated in the non-woven fabric 2 or the woven fabric 1 is dried and cured by heating it by passing it through the heating furnace 7 while feeding it horizontally on the transport roll 8. By curing the resin varnish in this way, a plurality of nonwoven fabrics 2 are laminated on the inner layer, a woven fabric 1 is laminated on the upper and lower outer layers, and a metal foil 6 (or release film) is further laminated on the upper and lower sides. A composite laminate A can be obtained. The composite laminate A is cut to an appropriate size by a cutting device such as a shear cutter 9 as necessary.

  A printed wiring board can be obtained by subjecting the laminated board A thus formed to appropriate wiring processing or through-hole processing by an additive method, a subtractive method, or the like.

  At this time, since the resin varnish containing the filler as described above is used in the present invention, unevenness is formed on the inner surface of the hole to be formed even when drilling is applied for forming the through hole. It is difficult to form the inner surface of the hole smoothly. For this reason, when a through hole is formed by applying hole plating to the inner surface of the hole, a high conduction reliability can be imparted to the through hole. It can be done.

Example 1
By the continuous method as shown in FIG. 1, two nonwoven fabrics impregnated with resin varnish are laminated, woven fabric impregnated with resin varnish is laminated on both sides of the laminate, and copper foil is arranged on the outermost layer, Subsequently, the laminated board A was continuously manufactured using the apparatus to heat-harden.

  As the resin varnish, 100 parts by weight of vinyl ester resin (manufactured by Showa Polymer Co., Ltd., product name “S510”), 1 part by weight of radical initiator (manufactured by Nippon Oil & Fats Co., Ltd., product name “Perbutyl O”), and styrene monomer 2 parts by weight, 60 parts by weight of wollastonite filler (Keiwa Furnace Co., Ltd., product name “Cycatech K-400”) was blended, mixed, and then degassed at 0.1 atm for 30 minutes under reduced pressure A varnish was used. The filler has a purity of 97.7% by weight, a calcite content of 0% by weight, a water content of 0.04% by weight, Ig. Loss is 0.79% by weight, pH is 11, magnetizing amount is 0.034 g, and average particle diameter (median diameter) is 23.55 μm.

  Then, a glass paper having a thickness of 0.3 mm (made by Honshu Paper Co., Ltd., product name “Clavest”) is used as the nonwoven fabric, and a glass cloth having a thickness of 0.19 mm (product name “7628” made by Asahi Sebel Co., Ltd.) is used as the woven fabric. And continuously supplying the impregnation apparatus at a speed of 2 m / min. The nonwoven fabric and the woven fabric are continuously impregnated with the resin varnish, and two nonwoven fabrics impregnated with the resin varnish are laminated and both sides of the laminate are laminated. A woven fabric impregnated with a resin varnish was laminated thereon. Further, a copper foil having a thickness of 18 μm was disposed as a metal foil on both outer sides, and then heat-cured at 105 ° C. for 20 minutes in a heat-curing furnace, and then heat-cured again at 170 ° C. for 30 minutes to obtain a 1.6 mm thick copper A stretched laminate A was obtained.

(Comparative Example 1)
A copper-clad laminate A having a thickness of 1.6 mm was obtained in the same manner as in Example 1 except that 60 parts by weight of spherical glass was added as a filler to be contained in the resin varnish.

(Comparative Example 2)
A copper-clad laminate A having a thickness of 1.6 mm was obtained in the same manner as in Example 1 except that 60 parts by weight of fibrous glass was added as a filler to be contained in the resin varnish.

(Evaluation test)
a. Drilling workability Three layers of laminate A are stacked, 6000 holes are drilled at 60000 rpm with a drill (drill diameter 0.6mm, deflection angle 35 °), and the inner surface of the 6000th hole is photographed Was observed with an SEM and observed, and the smoothness was evaluated according to the following criteria.
○: Maximum roughness less than 15 μm.
Δ: Maximum roughness 15 μm or more and less than 20 μm.
X: Maximum roughness 20 μm or more.

b. Drill wearability The wear rate of the drill blade after the above drill workability test is the ratio (percentage) of the size (area) of the drill blade after drilling to the size (area) of the drill blade before drilling. evaluated.

c. Punching characteristics Punching is performed on the laminate A with a punching pattern, and it occurs in insect bites (percentage of insect bites occurring in the outer periphery of 900 mm) and cracks between holes (15 holes in 2.00 mm interval, 2 rows) Number of cracks), perforation cracks (one-hole, two-hole (φ1 mm) perforation crack occurrence rate), end surface cracks (the distance from each end surface of the substrate to the center of the hole (φ1 mm) is 1 mm, 1 The incidence of end face cracks in each of the five holes of 5 mm and 2 mm) was derived with 6 samples.

d. Alkali resistance The laminate A was immersed for 60 minutes in a 10% strength aqueous sodium hydroxide solution at 80 ° C., and the weight change before and after that was derived.

e. Migration resistance evaluation Through holes for evaluation were formed in the laminate A obtained in each Example and Comparative Example so that the drill diameter was 0.9 mm and the distance between the walls was 0.45 mm. 85 ° C., 85% R.D. H. A voltage of 100 V was applied between the walls of the through-hole, and the time required for the electrical resistance value between the walls to be 2.0 × 105Ω or less was evaluated.

  The above results are shown in Table 1 below.

It is the schematic which shows an example of the manufacturing process of a composite laminated board.

Explanation of symbols

A Composite Laminate 1 Woven 2 Nonwoven

Claims (7)

  A composite laminate obtained by laminating one or a plurality of nonwoven fabrics impregnated with a resin varnish, laminating a woven fabric impregnated with a resin varnish on both sides of the laminate, and then heat-curing the composite laminate, the resin varnish A composite laminate, wherein the filler contained therein is wollastonite having a purity of 95% or more.   The composite laminate according to claim 1, wherein the filler has a water content of 0.1 wt% or less.   The composite laminate according to claim 1 or 2, wherein the filler has a pH of 7 or more.   4. The composite laminate according to claim 1, wherein the content of the filler in the resin varnish is in the range of 10 wt% or more and less than 60 wt% with respect to the total amount of the resin varnish.   The composite laminate according to any one of claims 1 to 4, wherein the amount of magnetization of the filler is 0.05% by weight or less.   6. The composite laminate according to claim 1, wherein the filler has an average particle size of 30 [mu] m or less.   The composite laminate according to any one of claims 1 to 5, wherein the filler is fibrous.

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