JPH06287328A - Resin-impregnated fiber sheet - Google Patents

Abstract

PURPOSE:To provide an insulating substrate which has properties, such as heat resistance, dimensional stability under heating, low water absorption properties, flame retardance, and high-frequency characteristics, well-balanced on a high level, is excellent in mechanical characteristics and processibility in, e.g. through- hole making of a circuit board, and is esp. suitable for a thin circuit board. CONSTITUTION:A resin-impregnated sheet is obtd. by impregnating a fiber sheet with a resin compsn. mainly comprising poly-p-phenylene sulfide in such a manner that the degree of orientation of the compsn. in the sheet is 0.3-0.9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-impregnated sheet obtained by impregnating a fiber sheet with a poly-p-phenylene sulfide resin, and more particularly to a resin-impregnated sheet suitable as an insulating base material for thin-type circuit boards. is there.

[0002]

2. Description of the Related Art In the fields of electric and electronic parts, various characteristics such as heat resistance, thermal dimensional stability, mechanical characteristics, low hygroscopicity, flame retardancy, and high frequency characteristics are required from the viewpoint of miniaturization and high functionality of equipment. The demand for high-dimensional and balanced circuit boards is increasing.
Furthermore, high-speed signal processing and thinning have been desired. Therefore, the insulating base material used for the circuit board also needs to satisfy the above requirements.

As insulating base materials in this field, base materials (hereinafter sometimes abbreviated as glass epoxy) in which glass cloth is impregnated with epoxy resin, polyimide films, fluorine-based films and the like are generally known. Further, an unstretched sheet of poly-p-phenylene sulfide (hereinafter sometimes referred to as PPS) (hereinafter sometimes referred to as PPS sheet) and a biaxially oriented film (hereinafter sometimes referred to as PPS film). Recently, the use of a resin on a circuit board has received a great deal of attention. Further, a laminate using a PPS film is (1) laminated with an aromatic polyamide fiber sheet via an adhesive (JP-A-60-63158).
No.), (2) a laminate with a fiber sheet which is infusible at a temperature of 300 ° C. and has a coefficient of thermal expansion at a temperature of 150 ° C. of 50 × 10 ⁻⁶ 1 / ° C. or less (JP-A-1-95585). ) Etc. Further, (3) a PPS molded sheet reinforced with a glass fiber sheet (Japanese Patent Publication No. 60-50146, etc.),
Further, it is known that the sheet is used as a printed wiring board (Japanese Patent Publication No. 60-52943, JP-A No. 59-3991, etc.).

[0004]

However, each of the above-mentioned films and laminates has the following problems.

Glass epoxy has a low hygroscopic property and is inferior in high frequency characteristics, and it is difficult to make it thin. The polyimide film has high heat resistance, but it easily absorbs moisture and is inferior in high frequency characteristics. Further, the fluorine-based film has poor adhesiveness, and it is difficult for conductive paste or plating to be applied when processing through holes.

On the other hand, the PPS sheet alone satisfies various characteristics such as thermal dimensional stability, low hygroscopicity, flame retardancy and high frequency characteristics, but has a lower heat resistance temperature than the biaxially oriented film (glass transition). If it exceeds the point, thermal deformation is likely to occur), and as the heating process increases, crystallization progresses and becomes brittle. When used as a printed circuit board, the crystal size and the like are controlled to satisfy heat resistance and brittleness to some extent, but there is a problem that thermal deformation easily occurs when heat is rapidly applied.

Further, since the PPS film itself causes a dimensional change due to heat shrinkage, when heat is applied in the manufacturing process of a circuit board, for example, a circuit shift easily occurs. Further, there is a problem that the laminated circuit board is easily torn during processing of through holes.

[0008] The heat resistance of the aromatic polyamide fiber sheet laminated with an adhesive is improved as compared with the PPS film, but the heat resistance of the adhesive adversely affects the substrate (that is, The heat resistance of the adhesive governs the heat resistance of the substrate as a whole), and the excellent characteristics of PPS cannot be fully utilized. In addition, the conductive paste may soak in during through-hole processing, or metal plating cannot be applied (fiber burr occurs and plating is difficult to ride). A laminate obtained by laminating a PPS film and a fiber sheet by heat fusion has poor adhesive strength and is easily peeled off when a force such as bending is applied. Furthermore, it lacks through-hole processability.

A molded sheet in which a glass fiber sheet is impregnated with PPS resin and reinforced with the fiber has heat resistance, thermal dimensional stability,
Although it is excellent in hygroscopicity, flame retardancy, high frequency characteristics, etc., cracks are likely to occur when a force such as bending is applied, and there is a problem in workability of the circuit board. In particular, the use was limited in the field where thinning is required.

The present invention solves the above problems.
That is, heat resistance, thermal dimensional stability, low hygroscopicity, flame retardancy, high-frequency characteristics and other various characteristics are balanced in a high degree, and mechanical characteristics, through-hole processability, and other circuit board processability are excellent.
In particular, it is to provide an insulating base material suitable for a thinned circuit board.

[0011]

In order to achieve the above object, the present invention has the following constitution, that is, a fiber sheet (A).
In a sheet in which the resin composition (B) containing poly-p-phenylene sulfide as a main component is impregnated with, the degree of orientation of the resin composition (B) is 0.3 to 0.9. The resin-impregnated fiber sheet.

The fiber sheet (A) in the present invention is a thin sheet composed of an aggregate of fibers, and is a generic term for cloth, cloth, felt, non-woven fabric, paper, etc., and has a thickness of 10 to 10.
It is preferably 700 μm, more preferably 10 to
It is 500 μm. For example, a glass fiber sheet, a liquid crystal fiber sheet, a carbon fiber sheet, a fluorine fiber sheet, an aramid fiber sheet or the like can be used. The fiber sheet may be processed for easy adhesion, coloring, etc. and may be prepared by mixing or laminating two or more kinds of materials, and the ratio of the basis weight (K) g / mm ² to the thickness (L) μm of the fiber sheet. A range of (K / L) of 0.3 to 1.2 is preferable for improving the directionality of dimensional stability. Among the fiber sheets, a glass fiber sheet is preferable in terms of electrical characteristics and thermal dimensional stability, and a glass fiber cloth is particularly preferable in terms of heat resistance, dimensional stability and processability, and among them, the average density of the warp and weft of the cloth. Ratio (average warp yarn density / weft yarn average density, hereinafter abbreviated as density ratio)
The range of 0.7 to 1.4 is preferable in terms of thermal dimensional stability.
Here, the impregnation means that the resin has entered into the surroundings of the elemental fibers constituting the fiber sheet, and has adhered and solidified with the elemental fibers.

It is preferable that the fiber sheet does not have a melting point up to a temperature of 400 ° C.
A fiber sheet that is infusible at a temperature of 00 ° C. Here, infusible means a state in which it does not melt or soften when exposed to a temperature of 400 ° C. If the fiber sheet used in the present invention does not have the above properties, the resin-impregnated fiber sheet of the present invention has insufficient thermal dimensional stability when exposed to a temperature near 300 ° C.

In the present invention, poly-p-phenylene sulfide (hereinafter sometimes abbreviated as PPS) means that 80 mol% or more (preferably 90 mol% or more) of the repeating unit is a constituent formula.

[Chemical 1] A polymer comprising a structural unit represented by If the amount of such a component is less than 80 mol%, the crystallinity of the polymer, the heat transition temperature, etc. are low, and the heat resistance, dimensional stability, mechanical properties, etc., which are the features of the resin composition containing PPS as a main component, are impaired.

In the above PPS, the repeating unit of 20
If it is less than 10% by mol, preferably less than 10% by mol, a unit containing a copolymerizable sulfide bond may be contained. The method of copolymerizing the polymer may be random or block type.

In the present invention, the resin composition containing poly-p-phenylene sulfide as a main component (hereinafter sometimes abbreviated as PPS composition) (B) means 60% by weight or more of poly-p-phenylene sulfide. A composition containing the same. P
If the PS content is less than 60% by weight, mechanical properties, heat resistance, heat fusion properties, etc. of the impregnated sheet made of the composition will be impaired.
Further, the remaining less than 40% by weight in the composition may contain additives such as polymers other than PPS, inorganic or organic fillers, lubricants and colorants. Furthermore, the melt viscosity of the PPS composition is a temperature of 300 ° C. and a shear rate of 200 sec.
Under the condition of ^-1 , the range of 100 to 50,000 poise (more preferably 500 to 20,000 poise) is preferable from the viewpoint of workability of lamination.

The resin-impregnated fiber sheet of the present invention is a sheet obtained by impregnating the above fiber sheet with a PPS resin composition, and the thickness of the sheet is preferably 50 to 1000 μm (more preferably 50 to 700 μm). The impregnation refers to a state in which a resin has entered around the fiber constituting the fiber sheet and adhered and solidified with the fiber. The impregnated state can be observed and measured from, for example, a cross-sectional photograph taken with an electron microscope. From the cross-sectional photograph, the impregnation rate described below was 85%.
It is preferably at least (more preferably at least 90%). If the impregnation rate is less than 85%, the thermal dimensional change rate becomes large,
Through-hole processability becomes difficult, and it becomes difficult to achieve the object of the present invention.

The ratio of the PPS resin layer to the fiber sheet of the resin-impregnated fiber sheet of the present invention is not particularly limited, but the thickness of the layer made of PPS alone (b) when observing each layer with a microscope from the cross section of the sheet. The ratio (b / a) of the thickness (a) of the fiber sheet layer impregnated with PPS is preferably in the range of 0.25 to 2.5 in terms of mechanical properties, impregnation rate and thermal dimensional stability of the sheet. . Further, the layer (a) does not necessarily have to be present at the center of the resin-impregnated fiber sheet in the thickness direction, and may be at a displaced position.

Furthermore, the degree of orientation of the layer (b) is 0.3 to
Must be 0.9. The term “orientation” used herein means Edge and En measured by a wide-angle X-ray diffraction method.
Orientation degree measured from the d direction (hereinafter referred to as OF)
That is, it is an essential requirement that it is in the range of 0.3 to 0.9 in any of the above directions.

Here, the degree of orientation measured from the edge direction (or end direction) means the X due to X-ray incidence from a direction parallel to the resin surface of the resin-impregnated fiber sheet and also parallel to the width direction (or longitudinal direction). Take a line plate photo, P
The degree of sunspot I when the diffraction intensity from the (200) plane of the PS crystal is scanned in the radial direction on the equator with a microdensitometer.
Similarly to (φ = 0 °), the degree I of black dots in the direction of 30 ° (φ = 3
It is defined by the ratio I (φ = 30 °) / I (φ = 0 °) of 0 °. When the OF is less than 0.3, the thermal dimensional change rate becomes large, and conversely, when it exceeds 0.9, the effect of improving the mechanical properties at the time of folding the resin-impregnated fiber sheet, which is the most object of the present invention, is lost. Therefore, the above requirements are important for achieving the object of the present invention.

The average surface roughness (Rt) of the resin-impregnated fiber sheet of the present invention is preferably 0.8 μm or less in order to increase the density of the electric circuit of the circuit board. Furthermore, in the resin-impregnated fiber sheet of the present invention, the maximum value that appears when the angle dependence of the molecular orientation degree of the PPS resin layer of the impregnated sheet is determined with a certain direction in the same plane of the sheet as a reference axis ( It is preferable that x) and the minimum value (y) are 4.0 or less (preferably 3.5 or less) in terms of isotropic properties such as thermal dimensional change rate and mechanical properties. The term "isotropic" as used herein means that the resin-impregnated fiber sheet has little directionality of characteristics, and when the above (x / y) exceeds 4.0, the dimensional change rate of the sheet of the present invention, mechanical properties The directionality of characteristics and the like tends to become large, and it tends to be difficult to manufacture a high-density circuit board.

Further, another base material (metal, sheet) is laminated on at least one surface of the resin-impregnated fiber sheet of the present invention, or another resin or coating agent is coated or molded. Good. Further, the resin-impregnated fiber sheet of the present invention may be oxidatively crosslinked with heat, ultraviolet rays or the like.

Next, a method for producing the resin-impregnated fiber sheet of the present invention will be described.

First, the PPS used in the present invention is obtained by reacting alkali sulfide and paradihalobenzene in a polar solvent at high temperature and high pressure. In particular, it is preferable to react sodium sulfide and paradichlorobenzene in an amide high boiling point polar solvent such as N-methylpyrrolidone. in this case,
In order to adjust the degree of polymerization, a so-called polymerization aid such as caustic alkali or alkali metal carboxylate is added,
It is preferred to react at ~ 280 ° C. The polymerization system pressure and the polymerization time are appropriately determined depending on the kind and amount of the auxiliary agent used, the desired degree of polymerization and the like. The obtained powdery or granular polymer is washed with water and / or a solvent to separate by-product salts, polymerization aids, unreacted monomers and the like.

If necessary, an inorganic or organic additive or the like is added to the polymer obtained above to such an extent that the object of the present invention is not impaired to obtain a PPS resin composition.

The resin-impregnated fiber sheet of the present invention is a sheet obtained by impregnating the fiber sheet (A) with the above-mentioned PPS resin composition (B). In order to control the content within the range, the method of thermocompression bonding to the fiber sheet using the stretched (orientated) film made of the resin composition is most preferable.

To obtain a stretched film of a PPS resin composition, first, the resin composition is treated at a temperature of 150 to 180 ° C. for 1 hour.
It is dried in vacuum for 3 hours, supplied to a melt extruder represented by an extruder, heated to a temperature not lower than the melting point of the polymer composition (preferably in the range of 290 to 350 ° C.), sufficiently kneaded, and then slit. A substantially non-oriented PPS sheet is obtained by continuously extruding the polymer into a sheet shape, molding the polymer into a sheet, and rapidly cooling the polymer to a temperature below the glass transition point of the polymer.

The obtained PPS sheet is sequentially biaxially stretched,
Stretching can be performed using a well-known stretching method such as a simultaneous biaxial stretching method, a tubular method, or a rolling method. A film stretcher can also be used when stretching in batch. For example, when the sequential biaxial stretching method is used, a uniaxially stretched film is obtained by first stretching the film in a longitudinal direction with a stretching machine composed of rolls. The stretching temperature at this time is 90 to 120 ° C.
And the draw ratio is preferably 1.3 to 4.5. Subsequently, the film is stretched in the width direction with a tenter. A biaxially stretched film can be obtained by using the same stretching conditions as those in the longitudinal direction. Further, if necessary, heat treatment is performed in a heat treatment chamber subsequent to the tenter under a constant length or a limited shrinkage of 15% or less. The heat treatment condition is 200 to 28
A range of 1 to 90 seconds at a temperature of 5 ° C is preferred. Further, if necessary, the film may be annealed under the limited shrinkage or free for the purpose of reducing the heat shrinkage rate of the film. The OF of the stretched film obtained above is preferably in the range of 0.1 to 0.75 in order to achieve the object of the present invention. It is particularly preferable to use a biaxially stretched film.

Next, a method for producing a resin-impregnated fiber sheet by thermocompression-bonding the fiber sheet and the PPS stretched film is as follows. The films are superposed on both sides of the fiber sheet, and the hot plate pressing method, the heating roll pressing method, A method of pressing between heated metal belts can be used. The press conditions at this time are as follows: temperature 290 to 350 ° C., pressure 1 to
30 kg / cm ² , and the time is 0.1 at the temperature required for impregnation.
5 to 3 hours are preferable in terms of impregnation rate and thermal dimensional stability,
Unless the above conditions are appropriately determined depending on the OF of the film used, the OF of the resin layer of the resin-impregnated fiber sheet obtained cannot be controlled within the range of the present invention, and the object of the present invention cannot be achieved.

The fiber sheet (A) and PP before thermocompression bonding
The thickness ratio (B / A) with the S film (B) is 0.3 to 3.
The range of 0 is preferable for achieving the object of the present invention.

[0031]

[Characteristic Evaluation Method] Next, the characteristic evaluation method and evaluation criteria used in the description of the present invention will be described.

(1) Measurement of Orientation Degree OF by Wide-angle X-ray Diffraction Method Sheets are aligned in a certain direction and formed into strips having a thickness of 1 mm, a width of 1 mm, and a length of 1 mm (each sheet is fixed by a collodion at the time of molding). A 5% aluminum acetate solution was used), and X-rays were incident (Edge and End directions) along the film surface of the sheet to take a plate photograph. As the X-ray generator, a D-3F type device manufactured by Rigaku Denki Co., Ltd. was used, and Cu-Ka rays passed through a Ni filter at 40 kV-20 mmA were used as the X-ray source. Sample-
The distance between the films was 41 mm, and a multiple exposure (15 minutes and 30 minutes) method was adopted using a Kodak non-screen type film. Next, the intensity of the (200) peak on the plate photograph was φ = 0 ° (on the equator line), 10 °, 20 °, 30 °.
The densitometer was scanned in the radial direction from the center of the photograph at the position, and the degree of blackening was read, and the degree of orientation (OF) of each sample was defined by the following equation.

OF = I (φ = 30 °) / I (φ = 0 °) where I (φ = 30 °) is the maximum intensity of the 30 ° scan, I
(Φ = 0 °) is the maximum intensity of the equatorial line scan. I (φ =
0 ° is I (φ = 0 °) and I (φ = 180 °), I (φ
= 30 °), the average value of the intensities of I (φ = 30 °) and I (φ = 150 °) was used.

Here, the measurement conditions of the densitometer are as follows.

The apparatus uses Sakura Microdensitometer model PDM-5 type A manufactured by Konishi Rokusha Kogyo Co., Ltd., the concentration range is 0.0 to 4.0 D (minimum measurement area is 4 μm ² ), and the optical system magnification is 100 times. Slit width 1 μm, height 1
0 μm is used, the film moving speed is 50 μm / sec, and the chart speed is 1 mm / sec.

(2) Resin impregnation rate (%) A cross section of the resin-impregnated fiber sheet was photographed with an electron microscope,
Obtained from the ratio of the sum of the arc lengths of the elementary fibers in which the elementary fibers are in contact with the resin or the adjacent elementary fibers to the sum of the diameters of the elementary fibers of the fiber sheet, and the measurement visual field is randomly set to 20 visual fields. The average value was defined as the resin impregnation rate (%). However, the magnification of the electron microscope was 3000 times. The resin impregnation rate is 85
% Or less, the through-hole workability described later is poor.

(3) Heat resistance A 2 cm square sample was floated in a solder bath set at a temperature of 280 ° C. for 30 seconds and evaluated according to the following criteria.

◯: No change at all Δ: Partly softened, deformed, peeled off, wrinkled ×: Deformed or peeled such as wavy or bent on the entire surface, and the dimensional change rate of each layer was large. It is a level that cannot be used as a circuit board.

(4) Heat shrinkage ratio A circuit board direction is used as a reference direction, and each of the reference direction and the reference direction is cut out into 100 mm × 10 mm in 90 ° direction, and a mark is attached to the conductor portion of the circuit to mark in the longitudinal direction. Read the distance exactly under the microscope (xmm). Next, after aging for 30 minutes in a furnace (hot air method) heated to a temperature of 240 ° C., the above distance is accurately measured (ym.
m). The heat shrinkage rate (%) in each direction was calculated by the following formula, and the value was shown in the direction of the larger heat shrinkage rate.

Thermal contraction rate (%) = (x−y) / x × 100 When the thermal contraction rate increases, the deviation of the circuit described later increases.

(5) Dielectric property (dielectric loss) The frequency was changed to examine the change in dielectric loss. JIS-C
It measured according to -6481.

(6) Displacement of Circuit The circuit board was passed through a furnace (far-infrared ray system) set at a temperature of 240 ° C. for 5 seconds, and the circuit was dislocated from that not passed through the furnace.

◯: Almost no circuit deviation, no problem at all Δ: There is a slight circuit deviation, but it is at a level that can be managed by correction during manufacturing of the circuit board ×: Large circuit deviation, circuit board It is a level that cannot be corrected during manufacturing

(7) Through-hole property In order to evaluate the through-hole processability of the circuit board as a model, a 2 mm diameter hole is punched in the resin-impregnated fiber sheet, and ink is used instead of the conductive paste to form the hole. Evaluation was made in the state of the ink that was brought into contact with the cut surface and permeated into the sheet. The judgment was made according to the following criteria.

◯: Ink soak length is less than 1 mm Δ: Ink soak length is 1 mm or more and less than 5 mm ×: Ink soak length is 5 mm or more When the workability is at the level of ×, it is short-circuited with another circuit in the insulating base material. It is a level that cannot be used as a circuit board.

(8) Mechanical Properties A resin-impregnated fiber sheet is repeatedly bent at an angle of 90 degrees,
The measurement was performed by the number of times of bending, which is the limit at which the resin layer cracks.

(9) Measurement of thickness ratio between PPS resin simple substance layer (b) of resin-impregnated fiber sheet and resin-impregnated fiber sheet layer It was determined from a cross-sectional photograph (magnification: 1000 times) with an electron microscope.

[0048]

EXAMPLES Next, the present invention will be described in detail with reference to examples.

Example 1 (1) Preparation of PPS composition In an autoclave, 32.6 kg (25
0 mol, containing 40% by weight of water of crystallization, 100 g of sodium hydroxide, 36.1 kg (250 mol) of sodium benzoate, and 76.2 kg of N-methylpyrrolidone (hereinafter sometimes abbreviated as NMP) were charged at 205 ° C. After dehydration in 34.1 kg of 1,4-dichlorobenzene (25
5 mol), and 20.0 kg of NMP are added, and 265 ° C.
And reacted for 4 hours. The reaction product is washed with water, dried and p
21.1 kg of poly-p-phenylene sulfide (yield 78%) was obtained, which consisted of 100 mol% of phenylene sulfide unit and had a melt viscosity of 3100 poise.

0.1% by weight of fine powder having an average particle diameter of 0.7 μm and calcium stearate 0.05
% By weight was added and melt-extruded at a temperature of 310 ° C. by an extruder having a diameter of 30 mm to prepare pellets of the PPS composition.

(2) Preparation of PPS Biaxially Stretched Film The above composition pellets were vacuum dried at a temperature of 180 ° C. for 3 hours. Furthermore, it is 3 by the extruder of 40mm diameter.
Melted at 10 ℃, 95% cut using wire mesh fiber Pore size 1
After filtering with a 0 μm filter, it was extruded from a T-die having a linear lip with a length of 400 mm and a gap of 0.5 mm, cast on a metal drum kept at a surface temperature of 25 ° C., and a 350 μm-thick unstretched sheet ( PPS sheet-
1) was obtained.

Next, the PPS sheet-1 was stretched by a longitudinal stretching apparatus consisting of rolls to a longitudinal method under the conditions of a temperature of 95 ° C. and a magnification of 3.5 times, and a subsequent tenter was used to stretch the temperature at 100 ° C. and a magnification of 3.5 times. It was stretched in the width direction under the conditions. Further, in a heat treatment chamber subsequent to the tenter, heat treatment was performed at a temperature of 270 ° C. under a restricted shrinkage of 5% to obtain a PPS biaxially stretched (oriented) film (PPS film-1) having a thickness of 25 μm. O of the film
F was 0.25 in both Edge and End directions.

(3) Preparation of Fiber Sheet As the glass cloth, a density ratio of warp yarns to weft yarns of 1.1, a basis weight of 47 g / m ² , and a thickness of 55 μm (EPC050: manufactured by Arisawa Manufacturing Co., Ltd.) were used. -1).

(4) Production of resin-impregnated fiber sheet A three-layer base material in which the fiber sheet-1 is sandwiched between two layers of the PPS film-1 is sandwiched between two SUS plates having a thickness of 3 mm, and further, A heat-resistant fiber sheet having a thickness of 5 mm was placed on a SUS plate and thermocompression bonded by a hot plate pressing method.
At this time, the press temperature is 320 ° C and the pressure is 10 kg / cm.
^{Is 2} . The pressing time at a temperature of 320 ° C. is 60 minutes. After pressing, it is a water-cooled method and a cooling rate of 2 ° C / min.
It cooled to the temperature of 0 degreeC, and obtained the 78-micrometer-thick PPS resin impregnation fiber sheet (impregnation sheet-1).

Comparative Example 1 PPS film-1 and fiber sheet-1 were pressed at a pressing temperature of 2
Two kinds of resin-impregnated fiber sheets were obtained by heat fusion at 95 ° C. and 370 ° C. under a pressure of 10 kg / cm ² and at that temperature for 120 minutes under the same conditions and methods as in Example 1. The resin-impregnated fiber sheet obtained at a pressing temperature of 295 ° C. is referred to as an impregnated sheet-2, and the resin-impregnated fiber sheet obtained at a temperature of 370 ° C. is referred to as an impregnated sheet-3.

Example 2 A PPS sheet was obtained by the method of Example 1, and the PPS sheet was made into a film stressor (manufactured by TM Long Co., USA).
Was simultaneously biaxially stretched at a temperature of 95 ° C. Stretching is 1.5, 2.0, 2.5, 3.0, 3.5, 4.5 in both length and width.
Six times as many PPS biaxially stretched films (PPS films-2 to 7) were obtained. The thickness of the film was adjusted to be 25 μm. Further, the film was sandwiched and fixed between two aluminum frames suitable for each size, and heat-treated under tension at a temperature of 265 ° C. for 60 seconds.

Further, the fiber sheet-1 and the PPS films-1 to 7 were heat-sealed under the conditions and the method of Example 1 to obtain 6 kinds of resin-impregnated fiber sheets (impregnated sheets-4 to 9 respectively).

Comparative Example 2 A PPS unstretched sheet having a thickness of 25 μm was obtained by the method of Example 1, and a fiber sheet-1 and a pressing temperature of 28 were obtained by the method of Example 1.
Heat fusion was performed at temperatures of 0 ° C., 295 ° C., and 320 ° C. to obtain three types of resin-impregnated fiber sheets (each impregnated sheet-1
0-12).

Example 3 Three kinds of biaxially stretched films (PPS film-8 to 1) having thicknesses of 16 μm, 50 μm and 75 μm were prepared by the method of Example 1.
0) was obtained. Each of the films was heat-sealed with the fiber sheet-1 to obtain three kinds of impregnated sheets. Impregnated sheets-13 to 1 in order from a resin-impregnated fiber sheet using PPS film-8
Set to 5. In addition, the conditions and method of heat fusion are the same as in Example 1.
Is the same as.

Example 4 PPS film-1 and fiber sheet-1 were thermocompression-bonded (temperature 31
0 ° C., pressure 10 kg / cm ² , speed 0.5 m / min),
Resin impregnated fiber sheet-16 was obtained.

Comparative Example 3 The PPS film-10 of Example 3 having a thickness of 75 μm was prepared.

Comparative Example 4 A PPS film-1 was subjected to a corona discharge treatment of 6000 J / m ^{2 on} one side, and the fiber sheet-1 was constructed as in Example 1.
Epoxy adhesive ("Chemit epoxy" TE-592
0 Toray Co., Ltd. was used for lamination. The adhesive is applied to the corona discharge treated surface of PPS film-1 by the gravure roll method.
μm (dry thickness) was applied and laminated on both surfaces of the fiber sheet-1. The drying condition of the adhesive was 100 ° C. for 3 minutes, and the laminating condition was 120 ° C. at a pressing pressure of 3 kg / cm ^{2 by} the hot roll pressing method. 150 ° C
It was heat-cured at the temperature of 2 hours (laminate-1).

The evaluation results of Examples and Comparative Examples are shown in Tables 1 and 2.

The resin-impregnated fiber sheet of the present invention has heat resistance,
It has excellent thermal dimensional stability, dielectric properties and mechanical properties.
Furthermore, it is the most suitable base material for circuit boards with high resin impregnation rate and excellent workability of through holes.

Example 1, Example 2, Comparative Example 1, Comparative Example 2
Therefore, if the degree of orientation of the resin in the resin-impregnated fiber sheet is not within the specific range referred to in the present invention, the dimensional stability and mechanical properties that are the objects of the present invention cannot be achieved. That is, if the degree of orientation of the resin of the impregnated sheet is less than 0.3, the rate of thermal dimensional change is large even if the impregnation with the fiber sheet is good, and conversely the degree of orientation is 0.
When it exceeds 9, there is no effect of improving the mechanical properties of the resin-impregnated fiber sheet. In order to obtain the effect of the present invention, oriented (stretched) PP (degree of orientation: preferably 0.1 to 0.75)
It can be seen that the object cannot be achieved without processing using the S film. It is necessary to appropriately select the processing conditions depending on the degree of orientation of the PPS film used.

From Comparative Example 2, it is preferable that the impregnation rate of the resin according to the present invention is not 85% from the viewpoint of thermal dimensional stability and through-hole processability.

In Example 3, the thickness of the resin alone of the impregnated sheet and the thickness of the fiber sheet impregnated with the resin were changed. When the thickness of the resin alone is small, it is effective for thermal dimensional stability, but the folds of the fiber sheet appear in the surface layer portion and the surface roughness becomes large, which may hinder the processing of high-density circuits. Conversely, as the thickness of the resin alone increases, the thermal dimensional change rate increases, and the thickness of the layer of PPS alone (b)
The ratio (b / a) of the thickness (a) of the fiber sheet layer impregnated with and PPS is preferably in the range of 0.25 to 2.5.

Although Example 4 is an impregnated sheet manufactured by the hot roll pressing method, the object of the present invention can also be achieved by this method.

Comparative Example 3 is a comparative evaluation of a single PPS film. It is understood that the object of the present invention is not achieved in terms of heat resistance and thermal dimensional stability. Furthermore, Comparative Example 4 is a laminate in which a PPS film and a fiber sheet are bonded together using an adhesive. The adhesive softens due to heat, the dimensional change rate cannot be suppressed, and the heat resistance is poor. The adhesive is PP
The excellent dielectric property of S is deteriorated. Further, since the resin does not enter the fiber sheet (not impregnated with the resin), the through hole processability is poor.

[0070]

[Table 1]

[Table 2]

[0071]

EFFECTS OF THE INVENTION The present invention has the above-mentioned constitution, that is, by keeping the degree of orientation of the resin layer of the resin-impregnated fiber sheet within a specific range, various characteristics such as heat resistance, thermal dimensional stability, and dielectric characteristics can be maintained. Moreover, the mechanical properties at the time of bending, which is required as the base material of the circuit board, can be greatly improved.

The resin-impregnated fiber sheet of the present invention can be applied to heat resistant insulating base materials for transformers, motors, etc., coating materials for cables used in high temperature and high pressure parts, heat resistant adhesive tapes, prepreg bases, in addition to circuit boards and laminated circuit boards. Suitable for materials, heat resistant labels, speaker cones, shield base materials, washers, and insulating spacer materials.

Claims (3)

[Claims] 1. A sheet obtained by impregnating a fiber sheet (A) with a resin composition (B) containing poly-p-phenylene sulfide as a main component, wherein the degree of orientation of the resin composition (B) is 0.3. The resin-impregnated fiber sheet is characterized in that it is ˜0.9. 2. The resin-impregnated fiber sheet according to claim 1, wherein the fiber sheet (A) is infusible at a temperature of 400 ° C. 3. The resin-impregnated fiber sheet according to claim 1, wherein the fiber sheet (A) is glass fiber.