JP2002064254A - Resin laminate plate for printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that conventionally laser workability, copper migration resistance, cost and contamination infiltration to cope with, while making printed wiring boards fine, thin type and low-cost. SOLUTION: The resin laminate board for printed wiring board is reinforced with nonwoven fabric of molten liquid crystal polyester fibers having a mean fiber size of 1-15 μm, a lengthwise solvent split length of 2.5 km or larger and an area shrinkage of 3% or less per hr. at 300 deg.C. When three shots of a carbon dioxide gas laser having a wavelength of 9.3 μm, a peak power of 2 kW and a pulsewidth of 15 μm are applied to bore holes of 100 μm into the board, the polyester fibers do not extrude in excess of 10 μm from the holes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin laminate suitable for a printed wiring board.

[0002]

2. Description of the Related Art Glass fiber fabrics have long been used as substrates for printed wiring boards, but glass fibers have the drawback of having a high dielectric constant and being heavy. In recent years, the use of liquid crystal aramid fibers has been studied. However, aramid fibers have high hygroscopicity and are not sufficiently satisfactory as a printed wiring board requiring excellent electrical insulation. From the above, it has been proposed to use a molten liquid crystalline polyester fiber having a low dielectric constant, a low specific gravity, and a low hygroscopicity as a printed wiring board substrate. For example, Japanese Patent Application Laid-Open No. 62-36892 describes a printed wiring board using a woven fabric made of a molten liquid crystalline polyester fiber as a base material. Spunlace method (water entanglement method)
It has also been proposed to use a dry nonwoven fabric obtained by the method as a base material for a printed wiring board (WO96 / 15306).
issue).

[0003] JP-A-7-48718 and JP-A-8-170295 describe papers obtained by wet-making a liquid crystalline polyester short fiber and a molten liquid crystalline polyester pulp, whereby a low specific gravity is obtained. It is possible to obtain a substrate for printed wiring boards having a non-water-absorbing property, a low dielectric constant, and a low dielectric loss tangent. However, these woven fabrics, non-woven fabrics and papers made of conventional fibers have coarser fibers and finer lines. At present, it is not possible to cope with micro-vias, denser, uniform and thin substrates. They not only make them small and thin, but also make laser processing, which is essential during processing difficult,
Further, the copper migration resistance is low due to insufficient density of the composite. In addition, according to the ordinary fiber production method and sheeting method, liquid crystal fiber is particularly rigid, so special spinning, short fiberization, sheeting, and post-processing are required, and the process becomes long and complicated. Not only does the cost increase, but it also causes contamination, which is the most avoidable for finer printed circuit boards.

[0004]

DISCLOSURE OF THE INVENTION The present invention is directed to a fine and thin printed circuit board, which can be manufactured at low cost.
The purpose is to resolve contamination.

[0005]

That is, according to the present invention, the average fiber diameter is 1 to 15 μm, the solvent breaking length in the longitudinal direction is 2.5 km or more, and the area shrinkage at 300 ° C. for 1 hour is small. A resin laminate for a printed wiring board reinforced with a nonwoven fabric of 3% or less of a molten liquid crystalline polyester fiber, having a wavelength of 9.3 μm, a peak output of 2 KW, and a pulse width of 15
A resin laminate for a printed wiring board, characterized in that when a carbon dioxide laser of μs is applied for three shots and a hole having a diameter of 100 μm is perforated, the molten liquid crystalline polyester fiber does not protrude more than 10 μm from the perforated portion.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The fiber base material (nonwoven fabric) used for the resin laminate for printed wiring boards of the present invention (hereinafter, may be simply abbreviated as "base material") is 1) a molten liquid crystalline polyester. A nonwoven web accumulated on a conveyor with a high-temperature and high-speed fluid from a die of an extruder is heated at a temperature of 90 ° C or higher, a melting point of a polymer or lower, and a linear pressure of 5 ° C.
Calendering is performed at a pressure of 0 kg / cm or more and 200 kg / cm or less to deform and fix the fiber entangled points fused at a pressure and a temperature.
C) to (the melting point of the polymer + 20 ° C) for 3 to 72 hours to increase the fiber strength.
It can be obtained as a fiber base material having excellent dimensional stability, heat resistance and resin adhesiveness.

[0007] The term "molten liquid crystallinity" as used in the present specification is also referred to as "melt anisotropy", and means that the liquid crystal exhibits optical liquid crystallinity (anisotropic) in a molten phase. Whether or not a polymer exhibits a liquid crystallinity can be easily known by a known method. For example, a method in which a sample (polymer) placed on a hot stage is heated and heated under a nitrogen atmosphere to observe the transmitted light. The presence or absence of liquid crystallinity can be checked by a commonly used method such as that described above.

The molten liquid crystalline polyester used in the present invention is a polyester comprising a repeating structural unit such as an aromatic diol, an aromatic dicarboxylic acid, or an aromatic hydroxycarboxylic acid. Molten liquid crystalline polyester consisting of a combination of units (1)
To (11). Of course, for the purpose of improving spinnability, the molten liquid crystalline polyester may have other copolymer units such as an isophthalic acid unit, if necessary, but from the viewpoint of fiber performance, etc. The proportion of the copolymer units is preferably small (usually 20 mol% or less).

[0009]

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Among the above-mentioned molten liquid crystalline polyesters, the total of the structural units comprising the parahydroxybenzoic acid unit (A) and the 2-hydroxy-6-naphthoic acid unit (B) represented by the following formula (3) is 65. Mol% or more, and preferably comprises a molten liquid crystalline polyester in which the ratio of 2-hydroxy-6-naphthoic acid unit is 5 to 45 mol% based on the total amount of both units, and the melt spinnability and fiber performance. This is particularly preferred from the viewpoint of:

[0011]

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The molten liquid crystalline polyester may be, if necessary, polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, polyarylate, polyamide, polyphenylene sulfide, polyester ether ketone, polyarylate as long as the effects of the present invention are not impaired. May contain one or more kinds of other polymers such as a fluorine-containing resin, and an inorganic substance such as titanium oxide, kaolin, silica and barium oxide, carbon black, a coloring agent such as a dye or a pigment or a dye, One or more of various additives such as an antioxidant, an ultraviolet absorber and a light stabilizer may be blended. From the viewpoint of fiber performance and the like, the content of components other than the molten liquid crystalline polyester is preferably 50% by mass or less, more preferably 30% by mass or less, based on the mass of the molten liquid crystalline polyester fiber. It is more preferably at most 10% by mass.

The non-woven fabric made of the molten liquid crystalline polyester used in the present invention is, for example, when the polyester is extruded from a nozzle, by blowing a high-temperature and high-pressure gas stream from a slit provided near the nozzle tip, thereby forming a spun polymer. It is preferable that the nonwoven fabric is manufactured by a so-called melt blown method, which is manufactured by blowing into a fine fibrous form and collecting it on a collecting surface (wire net) that is suctioning.

However, the molten liquid crystalline polyester conventionally used for melt blown nonwoven fabrics has a high melting point, so that it solidifies quickly and has a high viscosity. could not. On the other hand, in the present invention, by using a polymer having a melting liquid crystal polymer having a melting point of 280 ° C. or more and a melt viscosity of 25 Pa · s or less (temperature 320 ° C., shear rate 1000 / sec), good formation is obtained. A nonwoven fabric having heat resistance, dimensional stability, low water absorption, and resin impregnation can be obtained.

The average fiber diameter of the melt-blown nonwoven fabric is determined by the nozzle diameter, the discharge rate, the air speed, etc., and in the case of the present invention, it has a thickness of 0.3 to 35 μm, preferably 1 to 15 μm. And 60% or more of fibers having a size of 10 μm or less.

If the average fiber diameter is too large, there is a problem in the quality of a thin sheet. The thinner the sheet, the thinner the fiber group is needed to create a uniform sheet. For example, the density of the fiber base material is 0.57 and the thickness is 35 μm.
m, a basis weight of 20 g / m ² , a diameter of 1 in a prepreg using a normal fiber sheet (55% coating with the varnish of Reference Example 2).
One or more pinholes of not less than 2 mm are observed in 2-3 m. On the other hand, when the average fiber diameter is 1 μm or less, it is not preferable because the coating time with the varnish becomes long.

On the other hand, if the average fiber diameter is too large, the laser workability deteriorates. At present, carbon dioxide lasers are most widely used for printed wiring boards because of their low cost and performance. Wavelength 9.3 μm, peak power 2 kW, pulse width 15
When a hole having a diameter of 100 μm is formed by three shots of a carbon dioxide gas laser of μs, a few fiber ends (whiskers) often appear in the hole. When the average fiber diameter of the constituent fibers exceeds 15 μm, fiber ends (whiskers) of 10 to 30 μm frequently occur in the holes.

That is, if the average fiber diameter is too large, the conduction reliability decreases. That is, after drilling with a laser, the conductive paste of copper epoxy is filled without desmearing.
When measuring the chain resistance at a diameter of 500 m and 500 holes, if the average fiber diameter is 11 μm, the generation of whiskers is small and the resistance per hole is about 1 mΩ, but if it exceeds 15 μm, whiskers are generated. The insertion of the copper paste is poor, and the resistance value per hole reaches 1.5 mΩ.

When the thickness is 15 μm or more, the copper migration resistance of the substrate also decreases. That is, the hole diameter is 0.4 mm, the distance between holes is 1 mm, and the plating thickness is 25 μm.
Under the conditions of 5 ° C./85% RH / 100 VDC, a laminated board reinforced with fibers having an average fiber diameter of 11 μm can maintain an insulation resistance of 10 9 or more even after 1000 hours. , 9 of 10 in about 800 hours
Cut off. This is supposed to be affected by the subtle separation of the reinforcing fiber and the matrix resin.
It is believed that ion transfer along the fiber is promoted.

Another problem is the formation of the accumulated nonwoven fabric.
The thinner it is, the easier it is
When the CV is expressed as V (%) value of 3% or more, a preferable uniform prepreg cannot be obtained, and preferably 2% or less.

After the melt blown, the roll temperature is set on an off-line or on-line conveyor so that the surface of the non-woven fabric becomes 90 ° C. or more, which is higher than the glass transition point of the polymer.
Calender at kg / cm. Calendaring can be online or offline, but online is preferred. Generally, when the nonwoven fabric is calendered at a temperature of less than 90 ° C., the temperature does not reach the glass transition point of the polymer forming the nonwoven fabric, so that the fibers are hardly deformed and fixed, and the strength of the nonwoven fabric is increased because no embedding is formed. Absent. Therefore, the target thickness gradually returns to the original thickness and does not become the required product thickness. On the other hand, when the roll temperature exceeds the melting point of the polymer, the nonwoven fabric is fused to the calender roll, and roll winding occurs. In this case, in order to make the thickness more uniform, it is general to provide a gap between the rolls, and it is desirable to carry out a calender treatment with a gap around the expected thickness of the product.

When a calender treatment is performed at a roll linear pressure of less than 50 kg / cm, deformation and fixation of fiber entangled points or insufficient embedding causes the nonwoven fabric to return to its original shape. On the other hand, if the roll linear pressure exceeds 200 kg / cm, the fiber entangled points may be crushed or formed into a film, and workability in a subsequent process may be reduced.
Poor resin impregnation property. Therefore, the nonwoven fabric surface temperature is 90
C. or higher and polymer melting point or lower, linear pressure 50 kg / cm to 20
It is preferable to carry out calendering at 0 kg / cm.

In the present invention, the calendered nonwoven fabric is heat-treated in a high-temperature gas at a temperature of (polymer melting point−40 ° C.) or more and (polymer melting point + 20 ° C.) for 1 hour or more. Preferably, heat treatment is performed for 3 hours to 72 hours to improve the strength of the nonwoven fabric by promoting the fiber entangled points and the orientation of the fibers themselves, which are point-fused.

If the heat treatment is performed at a temperature lower than (the melting point of the polymer minus 40 ° C.), the solid phase polymerization of the polymer does not proceed, and the strength of the nonwoven fabric cannot be improved. Therefore, the heat treatment is preferably performed at a temperature of (the melting point of the polymer −30 ° C.) or more, more preferably at a temperature of (the melting point of the polymer −20 ° C.).

The heat treatment temperature is (polymer melting point + 20
If the temperature exceeds (° C.), the polymer softens and the fibers start to melt, and a part of the sheet becomes a film. For this reason, a problem occurs in the resin impregnating property in a later step.

As the gas used as the heating medium, a mixed gas such as nitrogen, oxygen, argon, carbon dioxide, or air is used. The gas used preferably has a dew point of -20 ° C or less. The heat treatment may be performed under tension or without tension depending on the purpose. In this way, after calendering, the nonwoven fabric is heat-treated in a heated gas at a temperature not lower than (the melting point of the polymer −40 ° C.) and not higher than (the melting point of the polymer + 20 ° C.). Advance the fiber entanglement point and the orientation of the fiber itself to increase the strength of the nonwoven.

The heat-treated nonwoven fabric has an area shrinkage of 3% or less after 300 ° C. × 1 hour, preferably an area shrinkage of 2% or less, excellent dimensional stability, and a melting point of 325.
It has high heat resistance of at least ℃ and a solvent breaking length of 2.5 km or more in the vertical direction.

As electronic devices have become smaller and have higher performance,
Device modules are becoming finer and more sophisticated, especially with respect to contamination. On the other hand,
The production line of paper and non-woven fabrics goes through the processes of spinning (fibrillation), bundling, cutting (shortening of fibers), papermaking, heat treatment, etc., to produce products (prepregs), during which various contaminants (for example,
Other fibers, minerals, bacteria, metal powder, etc.). These not only reduce the insulation reliability of fine wiring and the laser drillability of microvias, and reduce the product value such as appearance, but also reduce the yield in each post-process of the customer, and greatly affect the product delivery time and cost. Give. However, according to the melt blown method as in the present invention, the raw material polymer becomes a fiber sheet at once,
It is characterized in that the opportunity for contamination is minimized and sheets can be formed at low cost.

In general, microscopic contamination is generally judged visually. Although this largely depends on the application and the shape, one having a size of about 50 μm or more is counted, and one judgment is within 10 / m ² . For visual inspection, fire the nonwoven fabric or make it stand out by impregnation with resin, etc.
It can be determined on a desk of 0 looks under a convex lens of about 4 times.

The fiber base material used in the present invention is made of only a molten liquid crystalline polyester and has an average fiber diameter of 0.6 to 20 μm. It is fine, heat resistant, dimensionally stable, non-water-absorbing, and has a low dielectric constant in a high frequency band. It is a low-cost fiber base material that has a low dielectric constant and a low dielectric loss tangent and has extremely low contamination.

The fiber base material can be distributed and sold as it is. Also, a prepreg is produced by impregnating or attaching a thermosetting resin and / or a thermoplastic resin (matrix resin) to the fiber base material, and a single layer or a plurality of the prepregs are produced to produce a printed wiring board. can do. Suitable matrix resins used in the production of prepregs include, for example, phenolic resins, epoxy resins,
One or more thermosetting resins selected from an unsaturated polyester resin, a cyanate resin, a maleimide resin, a polyimide resin, and the like are exemplified. Further, one or two of the above-mentioned thermosetting resins may be polyvinyl butyral,
Thermoplastics such as acrylonitrile-butadiene rubber, those modified by adding a polyfunctional acrylate compound, or crosslinked polyethylene, bismaleide-triazine resin, crosslinked polyethylene modified epoxy resin, crosslinked polyethylene modified cyanate resin, polyphenylene ether modified cyanate resin, etc. A thermosetting resin modified with a resin (IPM-type or semi-IPM-type polymer alloy) or the like can also be used as the matrix resin. Among them, an epoxy resin, a polyimide resin, an unsaturated polyester resin, a cyanate resin and the like are suitable as a matrix resin for a printed wiring board. Further, a p-hydroxybenzoic acid unit (× unit) and a 2-hydroxy-6-naphthoic acid unit (Y
When a fiber composed of a melt anisotropic polyester mainly composed of (unit) is used, a bismaleide-triazine resin which is excellent in adhesiveness to the fiber and excellent in insulation properties and heat resistance is preferably used as the matrix resin.

[0032] The content of the matrix resin in the prepreg is not particularly limited, but from the viewpoint of suppressing delamination and poor molding and improving the mechanical performance, dimensional stability and thermal stability of the printed wiring board. Preferably, 30 to 95% by mass, particularly 40 to 80% by mass of the total mass of the prepreg is used as the matrix resin.

The method for impregnating or adhering the resin to the fiber base material is not particularly limited, and a conventionally known method may be used. For example, an impregnation method, a coating method, a transfer method, or the like may be employed. Specifically, a method in which a varnish prepared by dissolving a matrix resin in a solvent is impregnated into a fiber base and dried, and a liquid matrix resin in a normal temperature state or a heated state prepared without using a solvent is applied to the fiber base. A method of impregnation, a method of fixing a powdery matrix resin to a fiber base material, a method of forming a matrix resin layer on a release film or sheet and transferring the matrix resin layer to the fiber base material can be employed. Since the fiber base material used in the present invention has excellent resin impregnating properties, the entire printed wiring board base material can be impregnated with the resin, and excellent effects can be obtained. In the case of drying the matrix resin impregnated or attached to the fiber base material, it is preferable to dry the matrix resin in a non-contact state using a vertical dryer.

A printed wiring board may be manufactured using at least one prepreg obtained by such a method.
Specifically, a printed wiring board composed of a single layer of the prepreg, a printed wiring board formed by laminating two or more prepregs, one or more prepregs and other materials (for example, glass cloth, glass nonwoven fabric, other fibers A printed wiring board formed by laminating a cloth, a porous substrate, a plastic sheet, a plastic film, a plastic plate, etc.). In order to sufficiently achieve the effects of the present invention, it is preferable that the printed wiring board is composed substantially of only the base material of the present invention, in which case the mechanical performance, electrical characteristics, workability, etc. are good. It is more preferable to manufacture a printed wiring board by laminating about 2 to 5 prepregs.

A printed wiring board is obtained by laminating a metal layer on such a printed wiring board. The metal layer may be a single layer or a plurality of layers. Examples of the metal layer include a metal foil, a metal sheet, a metal plate, and a metal net, and in some cases, two or more of these may be used in combination. Further, the metal layer may be subjected to a surface treatment or the like. As a metal constituting the metal layer, copper, iron, aluminum, or the like is preferable, and among them, copper is preferably used. Of course, two or more of the above-mentioned metals can be used in combination. The thickness of the metal layer is preferably about 10 to 50 μm from the viewpoint of handleability, electric characteristics and the like. The bonding between the metal layer and the printed wiring board may be performed using an adhesive in some cases.

The method for manufacturing the printed wiring board is not particularly limited, and may be manufactured in the same manner as a conventionally known method. For example, one or two or more prepregs obtained by impregnating a resin into a fiber base material used in the present invention are used, and if necessary, other materials are used in combination. By curing and / or solidifying the matrix resin and bonding between layers, a desired printed wiring board can be manufactured. The heating temperature and pressure at that time are based on the type of matrix resin, the type of material to be laminated,
Appropriate conditions may be adopted according to the number of layers. Of course,
A plurality of prepregs may be laminated and integrated in advance, and then the metal layers may be laminated and integrated.

The thickness of the printed wiring board is preferably about 0.2 to 0.8 mm from the viewpoint of handleability and the like, and the specific gravity is 1.5 or less, particularly 0.8 to 1.4. Is preferred. Further, from the viewpoint of electrical characteristics, the dielectric constant of the printed wiring board is preferably 3.3 or less, particularly 2.0 to 3.2, and the dielectric loss tangent is 0.0098 or less, particularly 0.000085 to 0. .0095 is preferred.

[0038]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the following examples. The methods for measuring or evaluating various physical properties in Examples and Comparative Examples are shown below.

[Melt viscosity of molten liquid crystalline polyester (Pa
.S)] The viscosity of the molten liquid crystalline polyester is adjusted to a temperature of 300.
° C, shear rate r = 1000 sec ^-1Under the conditions
Graph (Toyo Seiki “Capillograph 1B”)
And measured.

[Melting point (° C.)] DSC apparatus (for example, Met
sampler into "TA3000" manufactured by Tler, Inc.
After weighing 20 mg and enclosing the same in an aluminum pan, nitrogen as a carrier gas is flowed at a flow rate of 100 cc / min.
The endothermic peak when the temperature was raised at 0 ° C./min was measured and determined. If a clear endothermic peak does not appear in the first run, the temperature is raised to a temperature 50 ° C. higher than the expected flow temperature at a temperature rising rate of 50 ° C./min, and after completely melting at that temperature for 3 minutes, 80 Cooled to 50 ° C at a rate of
Thereafter, the endothermic peak was measured at a heating rate of 20 ° C./min.

[Fiber diameter (μm)]
A photograph of the side surface of the fiber magnified 00 times was taken, and the fiber diameter was measured at any 10 points, and the arithmetic average was defined as the fiber diameter.

[Solution Breaking Length (km) of Printed Wiring Board Fiber Substrate] A test piece of longitude × weft = 200 mm × 150 mm was cut out from the printed wiring board base material, and the sample was immersed in methyl ethyl ketone at room temperature for 30 seconds. JIS P811
The strength in the warp direction and the weft direction was measured in accordance with 3-1976, the value was divided by the basis weight to calculate the solvent breaking length, and the arithmetic average was defined as the solvent breaking length. The solvent breaking length is an index mainly indicating the tensile strength of the fiber base material. Generally, the solvent breaking length is 0.
If it is 6 km or more, the process passability such as the resin impregnation step, the dimensional stability, etc. will be good.

[Area shrinkage of fiber base material (heat resistance)
(%)] A test piece (about 10 cm × 10 cm) collected from a printed wiring board substrate was placed in an oven at 280 ° C. for 24 hours.
The heat resistance was evaluated by measuring the time and the area shrinkage after heat treatment at 320 ° C. for 24 hours. The area shrinkage rate is defined as A (100 cm ² ), the area of the test piece before heat treatment, and B, the area of the test piece after heat treatment.
= {(AB) / A} × 100.

[Moisture Absorption] The calculation method after cutting out, adjusting and treating the sample is measured according to JIS C6481 (Testing method for copper clad laminate for printed wiring board). A = [(W2-W1) / W1] × 100 W2: Mass of sample after 60 ° C./95% RH / 7 days W1: Mass of sample obtained by drying W2 at 105 ° C. × 24 hours

Reference Example 1 [Production of melt-blown nonwoven fabric of molten liquid crystalline polyester] A molten liquid crystalline polyester resin (manufactured by Polyplastics Co .; Vectra A950, melt viscosity 20 Pa · s) was sufficiently dried with a low dew point air dryer. It was dried, extruded by a twin-screw extruder, and supplied to a melt blown nonwoven fabric manufacturing apparatus having a nozzle having a width of 1 m and a number of holes of 1,000. The blown conditions were a single hole discharge rate of 0.3 g / min, a resin temperature of 310 ° C., and a hot air temperature of 31.
At 0 ° C. and 20 Nm ³ , a nonwoven fabric having a basis weight of 39.8 g / m ² and an average fiber diameter of 11 μm was obtained.

Reference Example 2 [Preparation of matrix resin liquid (varnish)] 900 parts by mass of 2,2-bis (4-cyanatophenyl) propane and 100 parts by mass of bis (4-maleidophenyl) methane were added to 150 parts by mass.
After a preliminary reaction at 130 ° C. for 130 minutes, the resulting product was dissolved in 60 parts by mass of a mixed solvent of methyl ethyl ketone and N, N-dimethylformamide. 70 parts by mass of bisphenol A epoxy resin ("Epicoat 1001 (registered trademark)" manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent = 450 to 500) and 0.02 parts by mass of zinc octylate are dissolved in 50 parts by mass of the obtained solution. Thus, a matrix resin liquid (varnish) was produced.

Example 1 A melt-blown non-woven fabric made of the molten liquid crystalline polyester produced in the above-mentioned Reference Example 1 was prepared by heating the non-woven fabric at a temperature of 170 ° C. and a linear pressure of 100 kg / cm.
The fiber entangled points fused at the pressure and temperature are deformed and fixed, and then heat-treated in air at 300 ° C. for 15 hours to determine the entangled fiber points and the crystallinity of the fibers themselves. To increase the fiber strength. The basis weight is 40.
3 g / m ² , density 0.55 g / cm ³ , average fiber diameter of 11 μm, contained 60% or more of fibers of 10 μm or less, and had excellent strength and air permeability.

Example 2 Similarly to Reference Example 1, Vectra L-950 manufactured by the same company was used as a raw material polymer, the degree of polymerization was adjusted, and the same melt viscosity was adjusted to 20 Pa · s. Using the same conditions and equipment, a substantially similar melt blown sheet was prepared, and calendering and heat treatment were performed in the same manner as in Example 1. Result: 40.1 g / m
^{In step 2} , a sheet having an average fiber diameter of 11 μm was prepared.

The nonwoven fabric (fiber substrate) obtained above was impregnated with the matrix resin solution (varnish) prepared in Reference Example 3 and dried at 150 ° C. to obtain a resin content of 66 to 68% by mass.
Was produced. Four prepregs,
An 18 μm thick copper foil was laminated on both sides. The resin laminate was placed between the stainless steel mirror surfaces,
Under pressure of 0 kg / cm ² and a temperature of 200 ° C. for 2 hours, the laminate is formed by pressurizing and heating to a thickness of 0.40 to 0.45 mm.
Was manufactured. The physical properties of the printed wiring board thus obtained were measured or evaluated by the methods described above, and the results were as shown in Table 1 below.

Comparative Example 1 A polymer having the same composition as that of Example 1 (Vectra A950 manufactured by Polyplastics Co., Ltd.) was used as the polymer except that the melt viscosity was changed to 35 Pa · s by changing the polymerization conditions. Same as 1
Although the sheet was formed by the MB method, shots could not be prevented because of the high polymer viscosity, resulting in bad formation. Further, the average fiber diameter was as large as 16 μm, and the laser workability was poor.

Comparative Example 2 A molten liquid crystalline polyester staple fiber (commercially available Vectran HA 2.5d × 12) was used as the fiber base material.
mm, polymer is Vectra A, but solid-state polymerization is promoted by heat treatment, melting point is 320 ° C, fiber diameter is 17μ, fiber length is 12m
m), the paper is subjected to water wet entanglement by a normal wet spunlace method, and then subjected to calender treatment at a nonwoven fabric surface temperature of 170 ° C. and a linear pressure of 100 kg / cm, and fibers fused at a pressure and temperature. the inter-woven points is deformed fixed, then 15 hours at 300 ° C. at a heating in air, and heat treated in air, made from 100% liquid crystalline polyester fibers having an average fiber diameter of 17 .mu.m, basis weight 38 g / m ^2, a density 0.57 g / A non-woven fabric of cm ³ was produced. Thereafter, using the varnish of Reference Example 3, prepregs and laminates were prepared in the same manner as in the examples. The results are shown in Table 1 below.

Comparative Example 3 An average fiber diameter of 12 was used as a substrate.
40.5 g / basis mainly composed of para-aramid fiber of μm
Varnishes, prepregs, and laminates were prepared in the same manner as in the examples, using a wet nonwoven fabric having m ² and a density of 0.58 g / cm ³ . Table 1 shows the results.

[0053]

[Table 1]

Each evaluation in Table 1 is based on the following criteria. 1. Contaminants: The contents of contaminants include many other things such as other fibers, minerals, bacteria, and metal powders. It hinders the insulation reliability of fine wiring and the laser drilling property of microvias, and not only reduces the commercial value, but also lowers the yield in later processes, greatly affecting the delivery date and cost. Visual judgment. Count objects over 50 microns in size. Circles are given within 10 pieces / m ² . After the visual conditions and the nonwoven fabric were made to stand out by baking, resin impregnation, etc., judgment was made with a convex lens of about 4 times on a desk of 500 lux. 2. Laser workability: wavelength 9.3 μm, peak power 2KW,
When a carbon dioxide laser with a pulse width of 15 μs is applied for 3 shots (economical area) and a hole of 100 μm diameter is made, the length of the fiber protruding from the laser cut surface to the inside of the hole is 10 μm.
× if it is above. 3. Copper migration resistance; (Migration between copper through-holes)
After 4 mm perforation and 25 μm copper plating, 1 mm between holes, temperature 85 ° C., relative humidity 85%, DC 100 V environment, insulation resistance for 1000 hours or more, 10 or more to the 10th power or more was rated as ○.

[0055]

The printed wiring board base material and the substrate of the present invention are excellent in low water absorption, low dielectric constant, low dielectric loss tangent and dimensional stability due to polymer characteristics, and fineness, low contamination and cost by MB method. Is excellent. And, because of its fine homogeneity, it is excellent in workability (laser workability) and reliability (resistance to copper migration), and can greatly contribute to miniaturization and high performance required for printed circuit boards in the future.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) D04H 3/16 D04H 3/16 (72) Inventor Nagi Hisashi 1-2-1, Kaigan-dori, Okayama-shi Kuraray Co., Ltd. ( 72) Inventor Yoshio Kishino 1-2-1, Kaigan-dori, Okayama-shi Kuraray Co., Ltd. (72) Inventor Esaki Tamemaru 1-12-39 Umeda, Kita-ku, Osaka-shi, Osaka F-term (Kuraray Co., Ltd.) Reference) 4F100 AB01B AB01C AB17B AB17C AK41A AK43A AK53 AS00A BA01 BA02 BA03 BA06 BA07 BA10A BA10B BA10C BA13 DG01A DG15A DH01A EJ61A EJ82 GB43 JA03A JB08A JD15 JG04A JG05 JL01 JL10 JL01 JL04

Claims (5)

[Claims] 1. An average fiber diameter is 1 to 15 μm, a longitudinal solvent breaking length is 2.5 km or more, and 300 ° C. × 1
A resin laminate for a printed wiring board reinforced by a nonwoven fabric made of a molten liquid crystalline polyester fiber having an area shrinkage ratio of 3% or less over time, having a wavelength of 9.3 μm, a peak output of 2 KW, and a pulse width of 15 μs. 3 gas lasers
A resin laminate for a printed wiring board, characterized in that a molten liquid crystalline polyester fiber does not protrude from a perforated portion by 10 μm or more when a perforation of 100 μmφ is made. 2. A hole is drilled at a hole interval of 1 mm, and after copper plating,
In an environment of temperature 85 ° C, relative humidity 85%, DC 100V,
Insulation resistance, the printed wiring board resin laminate according to claim 1, 10 ¹⁰ or more can be maintained more than 1000 hours. 3. The resin laminate for a printed wiring board according to claim 1, wherein the nonwoven fabric is manufactured by a melt blown method. 4. A printed wiring board using the resin laminate according to claim 1. 5. An electronic / electric device incorporating the printed wiring board according to claim 4.