JP2002225029A - Thermoplastic resin-impregnated fiber sheet and circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin-impregnated fiber sheet which is suitable for an insulating material with excellent high frequency characteristics, low moisture absorption, flame retardance, heat resistance, thermal dimensional stability and processability as a circuit board such as through-hole processability by a laser and the circuit board using it. SOLUTION: The thermoplastic resin-impregnated fiber sheet manufactured by impregnating a fiber sheet with a melting point of 300-400 deg.C with a thermoplastic resin with a softening temperature of 240-300 deg.C is provided and the thermoplastic resin-impregnated fiber sheet characterized by a ratio (A/B×100(%)) which is a ratio of the thickness (A) of the fiber sheet layer to the thickness (B) of the whole sheet layer in the thermoplastic resin- impregnated sheet being 20-80% and the circuit board using the same are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin-impregnated fiber sheet for insulating a circuit board, which is capable of forming a depression on a circuit surface by molding, and which is excellent in heat resistance, thermal dimensional stability and workability by laser. And a circuit board using the same.

[0002]

2. Description of the Related Art In the field of electric and electronic parts, various characteristics such as solder heat resistance, high dimensional stability against heat and humidity, low water absorption and high frequency characteristics are considered to be high dimensions from the viewpoint of miniaturization and high performance of equipment. There is an increasing demand for an insulating base material that is balanced by:

Conventionally, as a circuit board (wiring board) used as a component of an electric / electronic device, a substrate made of glass cloth impregnated with an epoxy resin (hereinafter abbreviated as “glass epoxy substrate” for convenience), a polyimide film For example, a base material obtained by impregnating a fluorine-based resin into a fluorine-based film or a glass cloth is used. Furthermore, as a circuit board, a board using polyphenylene sulfide (hereinafter, may be abbreviated as “PPS”) has been proposed. Specifically, as a circuit board based on PPS,
Fiber sheet in which fibrous material is impregnated with PPS
No. 310957) is known.

[0004]

However, these conventional substrates each have the following problems. Glass epoxy substrates have poor high-frequency characteristics, and have problems with moisture absorption characteristics, so that dielectric characteristics are further degraded at higher frequencies. There is. Further, the polyimide film is excellent in heat resistance, but is inferior in high frequency characteristics and dimensional stability under moisture absorption. In addition, a substrate in which a fluororesin is impregnated into a fluorine-based film and a glass cloth has poor adhesion, and there is a problem that printing and lamination of metal foil and paste and plating during through-hole processing are difficult to mount. .

[0005] In the case of an unstretched sheet, the PPS film alone satisfies properties such as low moisture absorption, flame retardancy and high frequency characteristics, but has insufficient heat resistance as compared with a biaxially oriented film. As the number of processing steps increases, crystallization progresses and the material becomes brittle. When the crystal size and the like are controlled, there is no problem in terms of heat resistance and brittleness, but there is a problem that heat deformation easily occurs when heat is applied suddenly as in soldering.

A biaxially oriented PPS film has a high heat shrinkage. For example, when heat is applied in the process of manufacturing a circuit board, the film is deformed due to heat shrinkage, and circuit misalignment is likely to occur. For this reason, processing to reduce the heat shrinkage rate by an annealing process or the like is performed. However, when the heat shrinkage rate at 260 ° C. is 1% or less, there is a problem that the flatness of the film is significantly deteriorated. .

In the case of a sheet-like material in which a PPS resin is impregnated with a fibrous material such as glass cloth, heat resistance, thermal dimensional stability, moisture absorption, flame retardancy and high frequency characteristics are excellent.
Cracks are generated when a force such as bending is applied, heat sealing is poor, and there is a problem with the workability of the circuit board, such as difficulty in drilling through holes due to the lack of glass cloth due to the presence of glass cloth. . In particular, applications have been limited in fields where thinning and heat-fusibility are required.

An object of the present invention is to solve the above-mentioned problems, that is, by utilizing the excellent high-frequency characteristics, low hygroscopicity and flame retardancy of PPS, it is possible to accurately form a depression by molding on the surface of an electric circuit. An object of the present invention is to provide an insulating base material which is excellent in heat resistance and high-temperature dimensional stability of solder and the like, and is excellent in workability such as workability of via holes and through holes by a laser.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by a thermoplastic resin-impregnated fiber sheet containing a polyphenylene sulfide resin as a main component. The present invention has been reached.

That is, the thermoplastic resin impregnated fiber sheet of the present invention is a thermoplastic resin impregnated fiber sheet obtained by impregnating a fiber sheet having a melting point of 300 to 400 ° C. with a thermoplastic resin having a softening temperature of 240 to 300 ° C. The ratio (A / B × 100) of the thickness (A) of the fiber sheet layer to the thickness (B) of all sheet layers in the thermoplastic resin-impregnated sheet.
(%)) Is 20 to 80%.

Alternatively, the thermoplastic resin impregnated fiber sheet of the present invention is obtained by impregnating a fiber sheet having a glass transition temperature of 300 to 400 ° C. with a thermoplastic resin having a softening temperature of 240 to 300 ° C. A ratio (A) of the thickness (A) of the fiber sheet layer to the thickness (B) of all sheet layers in the thermoplastic resin-impregnated sheet.
/ B × 100 (%)) is 20 to 80%.

Further, the thermoplastic resin used for the thermoplastic resin-impregnated fiber sheet of the present invention is characterized in that it is a resin composition containing polyphenylene sulfide as a main component, or the fiber sheet of the present invention has a basis weight of 10 to 10. 10
Was 200 g / m ² or circuit board of the present invention, the thermoplastic resin impregnated fiber sheet of the above is used, the circuit characterized in that the recesses by molding and at least an electric circuit on one surface is formed It is a substrate.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.

In the present invention, the term "fiber sheet" refers to a thin leaf composed of an aggregate of fibers, for example, a woven fabric, a knitted fabric, a nonwoven fabric, or a paper made of fibers. For example, non-woven fabrics manufactured by a spunbond method, a melt blow method, a needle punch method, a thermal bond method, a water jet method, a papermaking method, and the like can be used. I don't care. In a nonwoven fabric manufactured by a papermaking method, a binder may be used for bonding fibers. However, the binder preferably has a decomposition temperature of 240 ° C. or higher from the viewpoint of solder heat resistance.

The thickness of these fiber sheets is 10 to 70
0 μm is preferred, and more preferably 10 to 50 μm.
0 μm. The basis weight (g / m ² ) of the fiber sheet is 1
It is preferably from 0 to 1000 g / m ² , more preferably from 10 to 700 g / m ² , in order to improve the thermal dimensional stability. As these fiber sheets, an aramid fiber sheet, a thermoplastic liquid crystalline resin fiber sheet, a carbon fiber sheet, a fluorine fiber sheet, a polyimide fiber sheet, a PBO fiber sheet and the like can be used. It is preferable in terms of stability and moldability. The fiber sheet may be processed such as easy adhesion and coloring, or may be a mixture or a laminate of two or more kinds of materials. Here, the impregnation means that the resin enters around the element fibers constituting the fiber sheet and is adhered and solidified to the element fibers.

The above-mentioned fiber sheet needs to have at least one of a melting point and a glass transition temperature of 300 to 400 ° C., and it is preferable that both are in the above temperature range. Especially when dimensional stability is required,
The glass transition temperature is preferably in the range of 300 to 400 ° C., and when moldability of the circuit board is required, the melting point is preferably in the range of 300 to 400 ° C.

On the other hand, if both the melting point and the glass transition temperature are less than 300 ° C., the thermal dimensional stability during soldering is insufficient, and if both are 400 ° C. or more, the workability by laser is reduced.

One of the important roles of the fiber sheet used in the present invention is as a reinforcing material for imparting high-temperature dimensional stability to a thermoplastic resin-impregnated fiber sheet using the fiber sheet. As the fiber sheet of the present invention, an aramid fiber sheet, a thermoplastic liquid crystalline resin fiber sheet and the like are preferable, and an aramid fiber sheet is most preferable in terms of thermal dimensional stability.

The thermoplastic resin suitably used in the present invention is, for example, a thermoplastic resin having a softening temperature in the range of 240 to 300 ° C. Here, the softening temperature is JIS K720.
Refers to the softening temperature measured according to 6. Softening temperature 24
If the temperature is lower than 0 ° C., the solder heat resistance is not sufficient. For example, the thermoplastic resin is partially melted in a solder reflow process at 240 ° C., and a circuit shift occurs. On the other hand, when the temperature is higher than 300 ° C., high temperature processing is performed, so that moldability is reduced. In the case of the present invention, as the thermoplastic resin having the above characteristics, polyphenylene sulfide is preferable because it has excellent characteristics such as dimensional stability of moisture absorption and dielectric characteristics.

The polyphenylene sulfide is a resin containing a PPS component preferably at least 80 mol%, more preferably at least 90 mol%. When the content of the PPS component is less than 80 mol%, the crystallinity and heat transition temperature of the polymer are low,
Heat resistance, which is a characteristic of a resin composition containing PPS as a main component,
Dimensional stability, mechanical properties, dielectric properties, etc. may be impaired.

In the above PPS resin, if the repeating unit is less than 20 mol%, preferably less than 10 mol%,
A unit containing another copolymerizable sulfide bond may be contained. As the repeating unit of less than 20 mol%, preferably less than 10 mol% of the repeating unit, for example, a trifunctional unit, an ether unit, a sulfone unit, a ketone unit, a meta bonding unit, an aryl unit having a substituent such as an alkyl group, Specific examples include a biphenyl unit, a terphenylene unit, a vinylene unit, and a carbonate unit, and one or more of them can be used. In this case, the constituent unit is
Any of random or block copolymerization methods may be used. Further, the PPS resin may be used alone or as a polymer alloy. As the polymer for alloy, polyester, liquid crystal polyester, polyamide, polyolefin, polyimide, polyamide imide, polyether imide, polyarylate, modified polyphenylene sulfide, polyether ether ketone, polyether ketone ketone, polyether sulfone, polysulfone, etc. are used. But not limited to these. The mixing ratio of the alloy polymer to the PPS resin is preferably about 0.1 to 30% by weight.

In the present invention, the resin composition containing polyphenylene sulfide as a main component refers to a composition containing 60% by weight or more of polyphenylene sulfide. When the content of PPS is less than 60% by weight, the impregnated sheet comprising the composition has mechanical properties, heat resistance, heat-sealing properties, moisture absorption dimensional stability,
Impairs dielectric properties. Also, the remaining 40 in the composition
Less than weight percent may include additives other than PPS, such as polymers, inorganic or organic fillers, lubricants, colorants, and the like. Further, the melt viscosity of the PPS composition is preferably from 100 to 50,000 poise, more preferably from 500 to 20,000 poise at a shear rate of 2000 sec ^{-1 at} 300 ° C., from the viewpoint of laminating processability.

The thermoplastic resin impregnated fiber sheet of the present invention comprises:
Although the above-mentioned fiber sheet is a sheet impregnated with a PPS resin composition, a method of impregnating the fiber sheet using a sheet made of the PPS resin composition is most preferable.

The sheet of the resin composition containing PPS as a main component is preferably one oriented at least uniaxially, but may be an unoriented PPS resin film.

For impregnation of the PPS resin composition sheet and the fiber sheet, the method of thermocompression bonding the PPS resin composition sheet and the fiber sheet to impregnate the resin into the fiber sheet is most preferred in the present invention.

The thickness of the PPS resin composition sheet before impregnation is preferably from 5 to 700 μm, more preferably from 5 to 500 μm. Impregnation refers to a state in which the resin enters around the elementary fibers constituting the fiber sheet and is tightly solidified with the fibers. Although there is no particular limitation on the impregnation rate, when each layer is observed with a microscope from the cross section of the sheet of the present invention, the ratio (A / B × 100) of the thickness (A) of the fiber sheet layer to the thickness (B) of the entire sheet layer is obtained.
(%)) Is preferably in the range of 20 to 80%. When the thickness of the fiber sheet layer is less than 20%, the resin composition layer becomes rich, so that the thermal dimensional stability is not sufficient. For example, when heat is received in a solder reflow process, a dimensional change of a circuit occurs. Further, when a circuit shape is formed by forming a depression on the sheet surface by die pressing, the cushion effect of the fiber sheet is weakened due to the low ratio of the fiber sheet layer, and a sufficient circuit groove depth is obtained after press transfer. Can not do. Further, when the thickness of the fiber sheet layer exceeds 80%, the resin-impregnated fiber sheet layer becomes rich, so that the thermal dimensional stability is improved, but the excellent moisture absorption dimensional stability and dielectric properties of PPS can be utilized. Can not. Therefore, in the fiber sheet layer of the thermoplastic resin-impregnated fiber sheet of the present invention, the thickness of the fiber sheet layer needs to be in the range of 20 to 80% with respect to the total thickness of the sheet layer.

Further, another substrate (metal or sheet) is laminated on at least one surface of the thermoplastic resin-impregnated fiber sheet of the present invention, or another resin or a coating agent is coated or molded. There may be. Further, the thermoplastic resin-impregnated fiber sheet of the present invention may be oxidatively cross-linked by heat or ultraviolet rays.

The thermoplastic resin impregnated fiber sheet of the present invention comprises:
Particularly, it is most suitable as a base material of a circuit board. The circuit board of the present invention is obtained by forming an electric circuit on at least one surface of the above-mentioned thermoplastic resin-impregnated fiber sheet.

An electric circuit is a path of electricity in which a conductor is patterned. As the conductor, a metal such as copper or aluminum, or a conductive paint containing copper, silver, carbon or the like is usually used. . Further, an electric component or an electronic component may be mounted on the electric circuit. Further, two or more circuit boards may be laminated. Such a circuit board can be easily drilled with a drill, a laser or the like. The circuit is formed by applying a photosensitive resin to a metal foil adhered to a thermoplastic resin impregnated fiber sheet, baking the circuit shape with light, removing the unexposed resin, and using copper There are a method of etching with an aqueous iron solution, a method of press-transferring a thermoplastic resin-impregnated fiber sheet with a mold having a circuit shape to form a depression, and pouring a conductive paint into the depression.

The thermoplastic resin-impregnated fiber sheet of the present invention comprises:
Since it has particularly excellent thermal dimensional stability and the surface layer is impregnated with a thermoplastic resin, it can be suitably used for a circuit transfer method using a die press.

Next, the thermoplastic resin-impregnated fiber sheet of the present invention and a method for producing a circuit board using the thermoplastic resin-impregnated fiber sheet will be described, but the present invention is not limited thereto.

First, as the PPS used in the present invention, a PPS resin produced by a conventionally known method can be used. For example, sodium sulfide and p-dichlorobenzene are converted to N-methyl-2-pyrrolidone (NMP).
The reaction is carried out at a high temperature and high pressure in an amide-based polar solvent.
If necessary, a copolymer component such as trihalobenzene can be included. As a polymerization degree regulator, caustic alkali or alkali metal carboxylate is added, and 230
The polymerization reaction is carried out at -280 ° C. After the polymerization, the polymer is cooled, and the polymer is filtered as a water slurry with a filter.
Obtain a granular polymer. In an aqueous solution such as acetate, 3
The mixture is stirred at 0 to 100 ° C for 10 to 60 minutes, washed several times with ion exchanged water at 30 to 80 ° C, and dried to obtain a PPS powder polymer. After washing the powdered polymer with NMP at an oxygen partial pressure of 10 Torr or less, preferably 5 Torr or less,
Wash several times with deionized water at 0-80 ° C and dry under reduced pressure of 5 Torr or less. Of course, if necessary, other polymer compounds, silicon oxide, magnesium oxide, calcium carbonate, titanium oxide, aluminum oxide, crosslinked polyester, crosslinked polystyrene, mica, talc, kaolin and other inorganic and organic compounds and thermal decomposition inhibitors, A heat stabilizer and an antioxidant may be added.

The thermoplastic resin-impregnated fiber sheet of the present invention comprises:
The sheet is a sheet in which a fiber sheet is impregnated with the above-mentioned PPS resin composition, and a method of thermocompression bonding to a fiber sheet using a non-oriented or stretched (oriented) film made of the PPS resin composition is most preferable.

A method for obtaining a non-oriented film of the PPS resin composition is as follows. First, the resin composition is vacuum-dried at a temperature of 150 to 180 ° C. for 1 to 3 hours, and supplied to a melt extruder apparatus represented by an extruder. After heating to a temperature equal to or higher than the melting point of the polymer composition, preferably in the range of 290 ° C. to 350 ° C. and sufficiently kneading, the mixture is continuously extruded from a slit-shaped die to form the polymer into a sheet and form a glass of the polymer. By rapidly cooling to a temperature below the transition temperature, a substantially non-oriented PPS sheet is obtained.

Next, a method for obtaining a stretched (oriented) film is as follows: the obtained non-oriented PPS sheet is subjected to a successive biaxial stretching method,
Stretching can be performed using a known stretching method such as a simultaneous biaxial stretching method, a tubular method, and a rolling method.

Next, in a method for producing a thermoplastic resin-impregnated fiber sheet by thermocompression bonding the fiber sheet and the PPS film, a film is placed on both sides of the fiber sheet and pressed. As a pressing method, a hot plate pressing method, a heated roll pressing method, a method of pressing between heated metal belts, or the like can be used. The pressing conditions at this time are a temperature of 250 ° C. to 350 ° C. and a pressure of 0.5 to 100 ° C.
kg / cm ² , and the time is 0.1 to
Three hours are preferred in terms of thermal dimensional stability and impregnation.

The method of providing the metal layer of the insulating base material thus obtained is performed by, for example, laminating the thermoplastic resin-impregnated fiber sheet of the present invention and a metal foil at a temperature of 200 to 350.
Heat fusion under the condition of 1 ° C. and pressure of 1 to 30 kg / cm ² ,
Also, a metal foil can be laminated by heat fusion simultaneously with the production of the thermoplastic resin impregnated fiber sheet. Further, a metal layer can be provided on the surface of the insulating base material by a method such as a vapor deposition method, a sputtering method, and a plating method. The metal layer of the insulating base material thus obtained is formed into a desired electric circuit by an etching method (for example, with an aqueous ferric chloride solution) to obtain a wiring board.

In addition, an electric circuit may be formed by using a conductive paste containing a metal such as silver, copper or the like or an alloy thereof or a conductor such as carbon by a method such as a silk printing method to obtain a wiring board. it can. Although it is possible to produce a wiring board by the above method, the thermoplastic resin-impregnated fiber sheet of the present invention, since the surface layer is a thermoplastic resin, hot-pressed by a mold having a circuit shape, the surface of the sheet After applying the circuit shape by thermal transfer of the dent,
An electric circuit can be formed by pouring a conductive paste containing a metal such as silver or copper and an alloy thereof or a conductor such as carbon into the depression. The conditions for hot pressing are as follows: pressing temperature 200-300 ° C, pressing pressure 1
１００100 kg / cm ² for 1 to 60 minutes.

In addition, when the thermoplastic resin impregnated fiber sheet is laminated, the mold is placed and hot pressed, so that the mold transfer and the heat fusion can be performed simultaneously. The obtained wiring boards can be combined to produce a multilayer circuit board. The multilayer circuit board is superimposed on two or more layers at a temperature of 20
A multilayer circuit board can be manufactured by heat fusion under the conditions of 0 to 350 ° C. and a pressure of 1 to 100 kg / cm ² .

The above-mentioned multilayer circuit board may be provided with through holes. The through-hole can be provided by a method such as a drill or a laser, but the circuit board of the present invention is preferably processed by a laser. Further, the respective layers can be connected to each other by a method such as a plating method. Further, electronic components and the like are mounted on the circuit board by soldering or the like as necessary.

[Measurement Method of Physical Properties] Next, the measurement methods used in the present invention will be described below. 1. Melting point and glass transition temperature Measured using a differential scanning calorimeter (DSICO SSC / 5200 manufactured by Seiko Instrument). 2. Softening temperature Measured according to JIS K7206. 3. Ratio of thickness of resin impregnated fiber sheet layer (A) to thickness of all sheet layers (B) Take a cross-sectional photograph of the laminate with an electron microscope, determine the thickness of the fiber sheet layer as (A), and the thickness of all sheets. (B), the thickness of each layer was determined from the photograph, and the thickness ratio of the fiber sheet layer was A / B ×
It was determined by 100. 4. Solder heat resistance A sample of a thermoplastic resin-impregnated fiber sheet cut into a 2 cm square was floated in a solder bath set at a temperature of 260 ° C. for 30 seconds and evaluated according to the following criteria.

○: No change at all △: Softening, deformation, peeling, wrinkles are partially observed ×: Deformation or peeling such as waving or bending on the front surface, and the dimensional change rate of each layer is large Heat shrinkage rate With reference to a certain direction of the thermoplastic resin-impregnated fiber sheet, 100 in each of the reference direction and the 90-degree direction of the reference direction.
Cut out to a size of 10 mm × 10 mm, mark the conductor part of the circuit, and read the distance between the marks in the longitudinal direction accurately with a microscope (xmm). Next, after aging for 5 minutes in a furnace (hot air system) heated to a temperature of 240 ° C., the distance is accurately measured (ymm). The heat shrinkage rate (%) in each direction was determined by the following formula, and the value was shown in the direction in which the heat shrinkage rate was large. Heat shrinkage (%) = (xy) / x × 100 As the heat shrinkage increases, the deviation of the circuit described later increases. 6. Transferability Depression depth (a) formed on film after press transfer
And the groove depth (b) of the mold were measured using a laser microscope VF7510 manufactured by Keyence Corporation, and the transfer rate (%) was determined. 6. Transfer rate (%) = (a / b) × 100 ○: Transfer rate is 90% or more Δ: Transfer rate is 60% or more and less than 90% ×: Transfer rate is less than 60% Circuit misalignment A circuit board made of a thermoplastic resin impregnated fiber sheet is
The mixture was passed through a furnace (hot air system) set at 30 ° C. for 30 seconds, and the circuit was shifted before and after passage.

：: There is almost no problem such as circuit deviation, and there is no problem. Δ: There is a slight circuit deviation, but it can be corrected by correction at the time of manufacturing the circuit board. ×: The circuit deviation is large and the circuit board is manufactured. 7. Level that cannot be corrected by correction of Through Hole Workability In order to modelly evaluate the through hole workability of the circuit board, through holes were formed in the thermoplastic resin impregnated fiber sheet using a UV yag laser manufactured by ESI. The laminate was cut so as to pass through the center of the through hole, the inner diameter (A) of the through hole was measured with an electron microscope, and the through hole ratio with respect to the thickness (B) of the laser beam was calculated.

Through-hole ratio (%) = A / B × 100 ○: Through-hole ratio is 90% or more Δ: Through-hole ratio is 60% or more and less than 90% ×: Through-hole ratio is less than 60%

[0045]

EXAMPLES Example 1 (1) Preparation of fiber sheet Kevlar nonwoven fabric manufactured by Dupont Teijin Advanced Paper Co., Ltd., having a thickness of 100 μm and a basis weight of 36 g / m ² was used. In addition,
The glass transition temperature of the Kevlar nonwoven fabric was 345 ° C. (2) Preparation of PPS composition Linear PPS resin (Ryton T1881) manufactured by Toray Industries, Inc.
And 0.2% by weight of silica fine powder having an average particle size of 0.7 μm, and 0.05% by weight of calcium stearate.
Is added and dispersed uniformly.
m, melted at 310 ° C., passed through a filtration filter that cuts foreign substances of 10 μm or more, lip width 1200 mm, lip gap 1.5
It was extruded into a film form from a T-die die having a diameter of mm. Applying an electrostatic charge to the molten film extruded in this way,
Casting drum with a surface temperature of 25 ° C (diameter 800m)
In step m), the mixture was solidified and cooled to obtain a PPS unstretched, unoriented sheet having a thickness of 50 μm. The softening point (melting point) of the unoriented PPS was 285 ° C. (3) Preparation of Fiber Sheet Impregnated with Thermoplastic Resin of the Present Invention and Production of Circuit Board A non-oriented PPS sheet is superimposed on both sides of the fiber sheet, and a mold for forming a circuit is provided on one of the surfaces. By hot pressing them, mold transfer and heat fusion were simultaneously performed. The condition of hot pressing is temperature 3
The pressure is 80 kg / cm ² and the pressing time (heating hold time) is 10 minutes. Then, the sheet is rapidly cooled to 80 ° C. in a pressed state, and the ratio of the thickness of the fiber sheet layer to the entire sheet layer is 45%. A PPS impregnated fiber sheet was obtained. A conductive paste was poured into the PPS-impregnated fiber sheet to obtain a circuit board. The circuit board thus obtained was excellent in high-temperature heat resistance and high-temperature dimensional stability, and was also excellent in through-hole workability. Table 1 shows the results. Example 2 An unoriented PPS sheet was obtained in the same manner as in Example 1, and the sheet was biaxially stretched by a successive biaxial stretching method. The stretching conditions are as follows: a longitudinal stretching device consisting of a roll group stretches in the longitudinal direction at a temperature of 95 ° C. and a magnification of 3.5 times, and is heated at a temperature of 1 at a subsequent tenter.
The film was stretched in the width direction at a condition of 00 ° C. and a magnification of 3.5 times. Further, in a heat treatment room following the tenter, a temperature of 270 ° C., 5%
35 μm thick biaxially oriented PP
An S film was obtained. The softening temperature (melting point) of the film is 2
85 ° C. Next, a PPS resin-impregnated sheet and a circuit board were produced in the same manner as in Example 1. The ratio of the thickness of the fiber sheet layer to all the sheet layers was 65%, and the obtained circuit board was excellent in high-temperature heat resistance and high-temperature dimensional stability, and also excellent in through-hole workability. Table 1 shows the results. Example 3 fiber sheet with a thermoplastic resin crystal polymer (manufactured by Sumitomo Chemical Co., Ltd. "SUMIKASUPER"), a non-woven fabric by a melt blow method, performs a pressure treatment by a calender roll, thickness of 50 [mu] m, a basis weight of 50 g / m ² A PPS resin-impregnated fiber sheet was produced in the same manner as in Example 1 except that the above-mentioned material was used. The melting point of the thermoplastic liquid crystal polymer fiber sheet was 335 ° C. Next, a circuit board was manufactured in the same manner as in Example 1. The ratio of the thickness of the fiber sheet layer to the entire sheet layer of the PPS resin-impregnated fiber sheet was 50%, and the obtained circuit board was excellent in high-temperature heat resistance and high-temperature dimensional stability, and also excellent in through-hole workability. It was a circuit board.

Table 1 shows the results. Comparative Example 1 A PPS resin-impregnated fiber sheet was produced in the same manner as in Example 1, except that a glass cloth manufactured by Arisawa Seisakusho Co., Ltd. was used. The glass cloth had a thickness of 50 μm, a basis weight of 47 g / m ² , and a glass transition temperature of 450 ° C.

Next, a circuit board was manufactured in the same manner as in Example 1. The ratio of the thickness of the fiber sheet layer to the entire sheet layer of the PPS resin impregnated fiber sheet was 50%, and the transferability of the circuit, the solder heat resistance, and the thermal dimensional stability were good, but the processing of the through-hole was good. The sex was x.

Table 1 shows the results. Comparative Example 2 Non-oriented PPS having a thickness of 150 μm in the same manner as in Example 1.
I got a sheet. The softening temperature (melting point) of the unoriented PPS sheet was 285 ° C. Example 1 using this sheet
A PPS resin-impregnated sheet and a circuit board were produced in the same manner as in the above. The ratio of the thickness of the fiber sheet layer to the entire sheet layer of the PPS resin-impregnated sheet was 18%, the transferability of the circuit was low, and the solder heat resistance was not sufficient. The PPS
When the circuit board obtained from the impregnated fiber sheet was passed through a 240 ° C. oven, the circuit was displaced.

Table 1 shows the results. Comparative Example 3 After a non-oriented PPS sheet having a thickness of 75 μm was obtained in the same manner as in Example 1, a circuit board was manufactured using the unoriented PPS sheet alone. The circuit board was provided with a mold on an unoriented PPS sheet and hot pressed. The hot pressing condition is temperature 25
The temperature was 0 ° C., the pressure was 80 kg / cm ² , the pressing time (heating hold time) was 10 minutes, and then the mixture was rapidly cooled to 80 ° C. in a pressed state. The conductive paste was poured into the press sheet to obtain a circuit board. The circuit board thus obtained had insufficient high-temperature heat resistance and high-temperature dimensional stability.

Table 1 shows the results. Comparative Example 4 Biaxially oriented PPS having a thickness of 75 μm in the same manner as in Example 2.
After obtaining the film, a circuit board was produced in the same manner as in Comparative Example 3 using the biaxially oriented PPS film alone.

The circuit board thus obtained had insufficient high-temperature heat resistance and high-temperature dimensional stability.

Table 1 shows the results.

[0053]

According to the present invention, a circuit shape can be formed by a depression by molding, and it is suitable as an insulating base material for a circuit board excellent in heat resistance, thermal dimensional stability, and workability of a through hole by laser. A fiber sheet impregnated with a thermoplastic resin and a circuit board using the same are obtained.

[0054]

[Table 1]

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) C08L 81:02 C08L 81:02 101: 00 101: 00 (72) Inventor Shinichiro Miyaji 2-chome Nihonbashi Muromachi, Chuo-ku, Tokyo No. 1 Toray Industries, Inc. Tokyo Office F-term (reference) 4F072 AA04 AB04 AB05 AB06 AB07 AB10 AB28 AB29 AD46 AL11 4L047 AA24 CA06 CB04 CB05 CB10 CC14

Claims (5)

[Claims] 1. A fiber sheet having a melting point of 300 to 400 ° C.
A thermoplastic resin impregnated fiber sheet impregnated with a thermoplastic resin having a softening temperature of 240 to 300 ° C., wherein all the sheet layers having a thickness (A) of the fiber sheet layer in the thermoplastic resin impregnated sheet are included. Ratio (A / B × 100) to thickness (B)
(%)) Is 20 to 80%. 2. A thermoplastic resin impregnated fiber sheet comprising a fiber sheet having a glass transition temperature of 300 to 400 ° C. and a thermoplastic resin having a softening temperature of 240 to 300 ° C.,
The ratio (A / B) of the thickness (A) of the fiber sheet layer to the thickness (B) of all sheet layers in the thermoplastic resin-impregnated sheet.
× 100 (%)) is 20 to 80%. 3. The thermoplastic resin-impregnated fiber sheet according to claim 1, wherein the thermoplastic resin is a resin composition containing polyphenylene sulfide as a main component. 4. A fiber sheet having a basis weight of 10 to 1000 g /
4. The thermoplastic resin-impregnated fiber sheet according to claim 1, wherein the fiber sheet is m ² . 5. A circuit board, wherein the thermoplastic resin-impregnated fiber sheet according to claim 1 is used, and at least one surface thereof is formed with an electric circuit and a recess formed by molding. .