JPH06286067A - Resin-impregnated fiber sheet - Google Patents

Abstract

PURPOSE:To balance various characteristics such as heat resistance, thermal dimensional stability, mechanical characteristics, etc., in high dimensions and to improve through-hole, thermal fusion-bonding processability by resin- impregnated fiber sheet having specific values of resin impregnating degree of resin composition, relative crystallization index, size of microcrystal, and a ratio of residual crystallization energy to crystallization energy. CONSTITUTION:A resin-impregnated fiber sheet is obtained by impregnating a resin sheet with resin composition containing poly-p-phenylene sulfide as a main ingredient in which resin impregnation degree of the composition is 80% or more, relative crystallization index is 2.5-13.0, a size of a microcrystal is 50-100 Angstrom and residual crystallization energy DELTAHt is 20-80% of crystallization energy DELTAHq of the composition. Of fiber sheets, a glass fiber sheet is preferable in view of electric insulation, thermal dimensional stability, and particularly cloth of glass fiber is preferable in view of points of heat resistance, dimensional stability and processability. Of which, a range of 0.7-1.4 of average density of warps to wefts of the cloth is preferable in view of thermal dimensional stability.

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 particularly to an insulating base material of a thin-wall type circuit board which requires heat fusion. The present invention relates to a suitable resin-impregnated sheet.

[0002]

2. Description of the Related Art In the fields of electric and electronic parts, miniaturization and high performance of equipment are rapidly progressing, and demands on insulating base materials used for the equipment are becoming severe. Above all, in the circuit board field, it was good if heat resistance, thermal dimensional stability, mechanical characteristics, flame retardancy, etc. were satisfied, but high frequency characteristics, low hygroscopicity, further thinning, fusion bonding (without using adhesive) Adhesive processing is possible), and it is desired that the above-mentioned various properties be balanced.

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. Furthermore, an unstretched sheet of poly-p-phenylene sulfide (hereinafter sometimes referred to as PPS) (hereinafter sometimes referred to as PPS sheet)
Also, the use of biaxially oriented films (hereinafter sometimes abbreviated as PPS films) for circuit boards has recently attracted particular attention. The laminate using the PPS film is (1) laminated with an aromatic polyamide fiber sheet via an adhesive (JP-A-60-63158),
(2) A laminate with a fiber sheet that 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). Are known. Further, (3) PP reinforced with a glass fiber sheet
S-molded sheet (Japanese Examined Patent Publication No. 50-50146, etc.), and use of the sheet for a printed wiring board (Japanese Examined Patent Publication No.
-52943, JP-A-59-3991, JP-A-2-
415004).

[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. Also, another prepreg (a glass epoxy resin stored without being completely cured) is used for the bonding process, but it is more difficult to reduce the thickness and the workability is poor. 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, high frequency characteristics, and heat fusion characteristics, but has a higher heat resistance temperature than the biaxially oriented film. Is low (heat deformation is likely to occur when the temperature exceeds the glass transition point), and crystallization progresses and becomes brittle as the heating process increases. 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 a poor adhesive force 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., when a force such as bending is applied, cracks are generated, and heat fusion is poor, and there is a problem in workability of the circuit board. In particular, applications have been limited in a field where thinness and heat fusion property are required.

Further, it has been proposed in Japanese Patent Laid-Open No. 2-415004 to impart heat-sealing characteristics.
Since the thermocompression bonding temperature with the PS sheet is below the melting point of PPS, the resin impregnation rate into the fiber sheet is low, through-hole processability, dimensional stability at high temperatures, and the temperature dependence of the thermal dimensional change rate are large and precise circuits. There was a limit to the development to the substrate.

The present invention solves the above problems,
That is, various characteristics such as heat resistance, thermal dimensional stability, low hygroscopicity, flame retardancy, mechanical characteristics, and high frequency characteristics are balanced in a high dimension, and circuit board workability such as through holes and heat fusion processability is excellent. Another object is to provide an insulating base material that is particularly suitable for a thinned circuit board.

[0013]

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 the main component is impregnated with the resin composition, the resin impregnation rate of the resin composition (B) is 80% or more and the relative crystallization index is 2.5. ~ 13.0, the size of the microcrystal is 50 ~ 100
Angstrom, the residual crystallization energy ΔHt is 20 to 80 of the crystallization energy ΔHq of the resin composition (B).
% Is a resin-impregnated fiber sheet.

The fibrous 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 and the like, having a thickness of 10 to 10.
It is preferably 700 μm (particularly preferably 10 to 500 μm), and 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. The basis weight (K) g / m of the fiber sheet
The ratio (K / L) of m ² to thickness (L) μm is 0.3 to 1.2.
The range is preferable for improving the directionality of dimensional stability.
Among the fiber sheets, a glass fiber sheet is preferable from the viewpoint of electrical insulation and thermal dimensional stability, and a glass fiber cloth is particularly preferable in terms of heat resistance, dimensional stability, and processability. Above all, the average density of the warp and weft of the cloth is preferable. Ratio (warp yarn average density /
Weft yarn average density, hereinafter abbreviated as density ratio) 0.7 to 1.4
Is preferable in terms of thermal dimensional stability.

It is preferable that the fiber sheet has no 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, 20 repeating units
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). Impregnation here means
It means that the resin has entered around the fiber constituting the fiber sheet and has been bonded and solidified with the fiber.

The resin impregnation rate of the resin-impregnated fiber sheet of the present invention is determined by taking a photograph of a cross section of the resin-impregnated fiber sheet with an electron microscope, The value obtained from the ratio of the sum of the arc lengths of the elementary fibers in contact with the adjacent elementary fibers is expressed in%. If the resin impregnation rate is less than 80%, the rate of thermal dimensional change cannot be suppressed to a practical level as a circuit board, and the conductive paste may soak into the sheet or the metal plating layer may be difficult to ride on, making through-hole processing difficult. 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 when each layer is observed with a microscope from the cross section of the sheet, the layer thickness (b) of the PPS simple substance is shown. 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.

The crystal structure of the resin layer of the resin-impregnated fiber sheet of the present invention is characterized by the following two sets of parameters measured by the wide-angle X-ray diffraction method.

First, the relative crystallization index is 2.5-13.
It is preferably 0 (more preferably 3.0 to 10.0). Here, the relative crystallization index means PP in the wide-angle diffraction profile by X-ray of the resin layer of the resin-impregnated fiber sheet.
Maximum intensity of (200) diffraction peak of S crystal (I ₂₀₀ ).
Is defined as the ratio I ₂₀₀ / I ₂₅ of the intensity (I ₂₅ ) at 2θ = 25 °. When the relative crystallization index is less than 2.5, the mechanical strength is poor in a high temperature atmosphere such as a solder bath, and deformation or thermal dimensional change rate becomes large. On the other hand, when the relative crystallization index exceeds 13.0, the mechanical properties of the sheet are deteriorated and the heat fusion property is deteriorated.

Second, the size of PPS microcrystals in the resin-impregnated fiber sheet (hereinafter sometimes abbreviated as ACS) is 50.
Must be -100 Angstroms. Here, the size of the microcrystals means the apparent crystal grain size obtained by applying the Scheller formula to the half width of the (200) diffraction peak of the PPS crystal. If the ACS is less than 50 Å, the resin-impregnated fiber sheet will have poor thermal dimensional stability and heat resistance, and conversely, if it exceeds 100 Å, the mechanical properties will be poor.

The degree of orientation of the resin layer is preferably 0.7 or more. The term "orientation degree" as used herein refers to Through, Edge measured by a wide-angle X-ray diffraction method.
And the degree of orientation (hereinafter, abbreviated as OF) respectively measured from the End direction, and it is preferable that the degree of orientation is 0.7 or more in any of the above directions from the viewpoint of thermal dimensional stability.

Here, the degree of orientation measured from a certain direction means that an X-ray plate photograph by X-ray incidence from that direction is taken and the diffraction intensity from the (200) plane of the PPS crystal is measured by a microdensitometer at the equator. The ratio I (φ = 30 °) / I (φ = 0) of the sunspot degree I (φ = 0 °) when the upper part is scanned in the radial direction and the sunspot degree I (φ = 30 °) in the 30 ° direction.
°).

The residual crystallization energy ΔHt of the resin layer in the present invention is the crystallization energy of the resin layer,
The resin portion is taken out from the resin-impregnated fiber sheet while observing it under a microscope with a microtome or the like, and a differential scanning calorimeter (DSC) is used.
At, it can be determined from the exothermic peak area of crystallization (Tcc) that appears when the temperature is raised. In addition, the crystallization energy ΔHq of the resin layer is the DS of the resin portion of the resin-impregnated fiber sheet.
To obtain from a crystallization exothermic peak area that appears when the temperature of the sample is raised to a temperature equal to or higher than the melting point of the resin in C, once melted, and then rapidly cooled with a refrigerant such as liquid nitrogen, the temperature is again raised in DSC. And ΔHt / ΔHq × 100 (hereinafter referred to as residual crystallization rate) is 20 to 80% (preferably 2).
It is necessary that the residual amount is 0 to 70% in view of dimensional stability and heat fusion characteristics, which are the objects of the present invention. That is, if the residual crystallization rate is less than 20%, it becomes difficult to impart the heat-sealing characteristics, and conversely, if it exceeds 80%, the characteristics such as dimensional stability and heat resistance deteriorate.

The resin-impregnated fiber sheet of the present invention satisfies various requirements as described above, whereby various properties such as thermal dimensional stability, heat resistance, mechanical properties, and heat fusion properties, which are the objects of the present invention, are balanced in a high dimension. The insulating base material is suitable for a base of a circuit board.

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 an alkali sulfide with paradihalobenzene in a polar solvent at high temperature and high pressure. In particular, it is preferable to react sodium sulfide with paradichlorzenen 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). The most preferable method is to use thermocompression bonding to the fiber sheet.

To obtain a film of the PPS resin composition, first, the resin composition is heated at a temperature of 150 to 180 ° C.
It is vacuum dried for 3 hours, supplied to a melt extruder device typified 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-shaped. Continuously extruding from the die, molding the polymer into a sheet and rapidly cooling to a temperature not higher than the glass transition point of the polymer to obtain a substantially non-oriented PPS unstretched film. Where the melting temperature is low, the kneading state is insufficient, or the cooling rate is slow, the crystal structure changes at the time of the film, and the control of the crystal structure of the resin layer of the resin-impregnated fiber sheet according to the present invention can be controlled. Hard to do. Further, the unstretched film obtained at this time is 2 times in an inert gas atmosphere by DSC.
The peak temperature (Tcc) generated when the temperature is raised to 20 to 180 ° C. at a rate of 0 ° C./min is in the range of 125 to 160 ° C. in order to control the crystal structure of the resin layer of the resin-impregnated fiber sheet of the present invention. Is particularly preferable.

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. in this case,
The OF measured in the Edge and End directions of the biaxially stretched film is preferably 0.1 or more from the viewpoint of controlling the relative crystallization index of the resin layer of the resin-impregnated fiber sheet referred to in the present invention. A balance of fusion property is secured.

For the resin-impregnated fiber sheet of the present invention, the above-mentioned unstretched film and stretched film can be used. For the purpose of the present invention, the unstretched film controls Tcc and the stretched film controls orientation degree. Is important to.

Next, a method for producing a resin-impregnated fiber sheet by thermocompression bonding the fiber sheet and the PPS 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 and the heating method are used. A method of pulling between the metal belts can be used. The press conditions at this time are as follows: temperature 290 to 350 ° C., pressure 1 to 30 k
g / cm ² , and the time is 0.5 to 3 depending on the temperature required for impregnation.
Time is preferable in terms of impregnation rate and thermal dimensional stability, but the crystallinity of the film to be used varies depending on the type of film, and the crystal structure of the resin layer of the resin-impregnated fiber sheet obtained unless properly determined can be controlled within the range of the present invention. Therefore, 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.

Further, the powdery, granular or pelletized copolymerized PPS composition is directly contacted with the fiber sheet and impregnated under the above conditions, and then a PPS unstretched film or stretched film is laminated (thermocompression bonding). There is also a way to do it.

Further, after the laminated structure of the present invention is formed by the above-mentioned method or other methods, the surface of the laminated body can be polished or etched by a physical or chemical method to obtain a final product. However, there is no problem if the requirements of the present invention are satisfied.

[0042]

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

(1) Wide-angle X-ray Diffraction Method ACS and Relative Crystallization Index The method of rotating the sample on the inner surface was adopted to eliminate the orientation effect of the sample, and the diffraction pattern was measured by the reflection method. The X-ray generator is a Rigaku Denki D-8C type device, and is 35 kV
X-ray the Cu-Ka wire that passed the Ni filter at -15 mA.
It was used as a radiation source. The Rigaku Denki PMG-A2 type was used as the goniometer, and a rotary sample table that rotates the sample at a rotation speed of 80 rpm was attached, and the slit system was Diversences.
lit1 °, Receiting slit 10.1
5 mm, Scattering slit 1 ° was adopted. The 2θ search speed is 1 / minute, and the chart speed is 1 cm / minute. Each sample was cut into a square having a side of 20 cm and stacked to have a thickness of 0.5 mm to obtain a measurement sample.

From the full width at half maximum of the (200) diffraction peak, Sch
The apparent crystal size (ACS) was calculated using the eller formula.

ACS = Kλ / β cos θ, β = [P ² −
(P ′) ² ] ^1/2 where K: Scheller constant (K = 1) λ: X-ray wavelength (λ = 1.5418 angstrom) 2θ: Bragg angle (°) β: half-value width after correction (radian) ) P: half-value width measured P ': half-value width of the standard sample for correction (Si single crystal) The relative crystallization index is the maximum intensity (I ₂₀₀ ) of the (200) peak and 2θ = 25 from the diffraction profile of each sample. Intensity (I ₂₅ ) was measured as the internal standard value, and the ratio of the two was defined as the relative crystallization index (I ₂₀₀ / I ₂₅ ).

Degree of orientation (OF) Samples are aligned in a certain direction to have a thickness of 1 mm, a width of 1 mm, and a length of 1.
It was molded into a rectangular strip of mm (fixing of each sheet at the time of molding was using collodion's 5% aluminum acetate solution), and X-rays were incident along the film surface of the sheet (Tough, Edge and En).
Plate direction was taken. The X-ray generator is a Rigaku Denki D-3F type device, and is 40 kV-20 mA.
The Cu-Ka ray that passed through the Ni filter was used as the X-ray source. The sample-film distance was 41 mm and the multiple exposure (15 minutes and 30 minutes) method was adopted using Kodak non-screen type film. Then on the plate photo (20
0) The intensity of the peak is φ = 0 ° (on the equator line), 10 °, 2
The densitometer was scanned in the radial direction from the center of the photograph at the positions of 0 ° and 30 ° to read the degree of blackening, and the degree of orientation (O
F) was defined by the following formula.

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

(2) Residual Crystallization Rate The residual crystallization energy (ΔHt) / crystallization energy (ΔHq) × 100 was obtained, and the unit was expressed as%.

Here, ΔHt (cal / g) is obtained by taking out the resin layer of the surface layer portion of the resin-impregnated fiber sheet and measuring PERKIN.
The exothermic peak area of crystallization (Tcc), which appears when the temperature was raised to 20 to 180 ° C. under the following conditions in an inert gas atmosphere with an ELMER DSC-2 type investigative calorimeter, was calculated (half-value width × Height, base × height / 2) or a gravimetric method, a value obtained from the peak area of indium as a reference substance, and a constant L were calculated and obtained by the following formula.

Measurement conditions: sample weight 5 mg range 5 mcal / sec · m chart speed 40 mm / sec temperature increase rate 20 ° C./min

ΔHt = [L × range × peak area (cm
² )] / [Sample weight x chart speed (cm / se
c)]

For ΔHq, the resin layer in the surface layer of the resin-impregnated fiber sheet is taken out and heated at 20 to 340 ° C. in an inert gas atmosphere by DSC to melt it. Then, after rapidly cooling with a coolant such as liquid nitrogen to obtain a non-oriented, non-crystallized sample, it was determined again using DSC under the same conditions as the measurement of ΔHt.

(3) Crystallization temperature (Tcc) The PPS film was changed to PERKIN ELMER DSC-
The peak of crystallization (Tcc) that appeared when the temperature was raised to 20 to 180 ° C under the following conditions was read with a type 2 investigation investigation calorimeter.

Measurement conditions: sample weight 5 mg range 5 mcal / sec · m chart speed 40 mm / sec temperature increase rate 20 ° C./min

(4) 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 impregnation rate (%). However, the magnification of the electron microscope was 3000 times. When the resin impregnation rate is 85% or less, the through hole processability described later is poor.

(5) 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 over 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.

(6) Thermal shrinkage ratio The direction in which the circuit board is located is the reference direction, and the reference direction and the 90 ° direction of the reference direction are each 100 mm × 10 mm.
Then, the conductor portion of the circuit is marked, and the distance between the marks in the longitudinal direction is accurately read with a microscope (x mm).
Next, after aging for 30 minutes in a furnace (hot air method) heated to a temperature of 240 ° C. and 265 ° C., the above distance is accurately measured (ymm). 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.

(7) Dielectric Properties (Dielectric Loss) Changes in the dielectric loss were examined by changing the frequency. JIS-C
It measured according to -6481.

(8) Displacement of Circuit The circuit board prepared by printing the conductive paste by the screen printing method is passed through a furnace (far-infrared ray method) set at a temperature of 260 ° C. for 5 seconds, and is not passed through the furnace. I saw a circuit shift from the thing.

◯: Almost no circuit deviation and no problem. Δ: There is a slight circuit deviation, but it is at a level that can be used by correction during manufacture of the circuit board. ×: Large circuit deviation, circuit board. Is a level that cannot be corrected during manufacturing

(9) 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 soaked length is less than 1 mm Δ: Ink soaked length is 1 mm or more and less than 5 mm ×: Ink soaked 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.

(10) Mechanical Properties A resin-impregnated fiber sheet was cut into a width of 19 mm, and a polyester adhesive tape (made by Knitto: polyester adhesive tape, No. 31B) was cut on the front and back of the sample for the purpose of surface protection to avoid other factors. Adhesion was performed, the portion was sandwiched between fixing jigs, bent at an angle of 90 degrees, and the number of times of bending and the observation of cracks generated in the sheet were observed, and the evaluation was performed according to the following criteria.

◯: The number of bends in which cracks occur is 5 or more Δ: The number of bends in which cracks occur is 2 or more and less than 5 times ×: The number of bends in which cracks occur is less than 2 times. Cracks occur in the circuit board manufacturing process, resulting in poor insulation.

(11) 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.

(12) Fusing Property Heat Fusing Strength A rolled copper foil having a thickness of 35 μm was heat fused at a temperature of 300 ° C. on the surface of the sheet, and the peel strength (kg / cm) of the copper foil was evaluated. . The heat fusion method is a hot plate pressing method, the pressing time under the above temperature is 0.5 hours, and the pressing pressure is 10 kg / cm ^2.
And In addition, the peel strength is measured using a shopper.
It was evaluated at a peeling speed of 50 mm / min at an angle of 80 degrees.

Heat fusible sheets were superposed on each other so as to have a thickness of 1 mm, heat-fused under the same conditions as the above-mentioned sample for measuring the fusion strength, and the laminated sheet was broken to obtain the following state. It was evaluated according to the standard.

◯: There is no peeling in the fractured part Δ: Peeling generated in the fractured part is less than 30% of the fractured part ×: Peeling occurred in the fractured part is 30% or more of the fractured part The above-mentioned × is for a multilayer circuit board or the like. This level is unusable in fields that require self-adhesiveness.

[0072]

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

Example 1 (1) Preparation of PPS composition 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, and sufficiently kneaded and melt-extruded at a temperature of 310 ° C. by an extruder having a diameter of 30 mm to obtain PPS.
A pellet of the composition was made.

(2) Preparation of PPS 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.
95% with wire mesh fiber melted at 10 ℃ and kneaded thoroughly
After filtering through a filter with a cut hole diameter of 10 μm, the length is 4
An unstretched sheet (PPS film-1) having a thickness of 25 μm was obtained by extruding from a T die having a linear lip of 00 mm and a gap of 0.5 mm and casting on a metal drum whose surface temperature was kept at 25 ° C. The Tcc of the obtained film was 142.
It was ℃.

(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 (fiber sheet). -1).

(4) Manufacture 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, Further, a heat-resistant fiber sheet having a thickness of 5 mm was placed on the 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).

Example 2 A resin-impregnated fiber sheet was prepared by the method of Example 1 except that the thermocompression bonding conditions were changed (impregnation sheet-2). The thermocompression bonding temperature was 330 ° C., the pressure was 8 kg / cm ² , and the hot pressing time was 2 hours, and the temperature was cooled to 60 ° C. at a cooling rate of 5 ° C./min.

Example 3 PPS was polymerized by the method of Example 1 and the degree of polymerization was adjusted so that the Tcc of the unstretched PPS film obtained was 125 ° C. Other conditions were the same as in Example 1 to obtain PPS film-2 and further impregnated fiber sheet (impregnated sheet-3).

Comparative Example 1 When an unstretched PPS film was obtained from the PPS resin composition by the method of Example 3, the film cast was gradually cooled. The Tcc of the unstretched PPS film obtained here was 121 ° C. (PPS film-3). Using this film, the resin-impregnated fiber sheet (impregnated sheet-4) under the conditions of Example 2
Got

Comparative Example 2 The PPS film-2 and the fibrous sheet-1 having the structure of Example 1 were heat fusion bonded by a small autoclave. The conditions for thermocompression bonding were a temperature of 350 ° C., a pressure of 10 kg / cm ² , and a pressure bonding time at this temperature of 4 hours in a nitrogen atmosphere. 1 hour at 300 ° C, 1 hour at 250 ° C, 2
After cooling at 00 ° C for 1 hour, it was cooled to a temperature of 60 ° C (impregnated sheet-5).

Example 4 PPS film-1 was prepared by the method of Example 1 into fiber sheet-1.
Was heat-sealed. Press temperature at this time is 30
The temperature was 0 ° C. and the pressure was 10 kg / cm ² . Further, the cooling was rapidly carried out to 200 ° C., and from 200 to 60 ° C. under the conditions of Example 1 to obtain a resin-impregnated fiber sheet (impregnated sheet-6).

Comparative Example 3 By the method of Example 4, the cooling rate after hot pressing was rapidly cooled to 60 ° C. at a temperature of 300 ° C. (impregnated sheet-7).

Example 5 An unstretched PPS film was obtained by the method of Example 1, and the film was biaxially stretched by the sequential biaxial stretching method. As for the stretching conditions, a longitudinal stretching apparatus consisting of rolls is used to stretch the material in a longitudinal direction at a temperature of 95 ° C. and a draw ratio of 3.5 times, and a subsequent tenter is used for stretching at a temperature of 10
The film was stretched in the width direction at 0 ° C. and a magnification of 3.5. Further, it was heat-treated in a heat treatment chamber subsequent to the tenter under the restriction shrinkage of 270 ° C. and 5% to obtain a PPS biaxially stretched (oriented) film (PPS film-3) having a thickness of 25 μm. O measured from the Edge and End directions of the film, respectively
F was 0.27 and 0.28, respectively. Next, in the same manner as in Example 1, resin-impregnated fiber sheet (impregnated sheet-8)
It was created.

Comparative Example 4 By the method of Example 5, the temperature was 295 ° C. and the pressure was 10 kg / c.
A resin-impregnated fiber sheet (impregnated sheet-9) was prepared under the conditions of m ² and pressing time of 2 hours. The cooling conditions are the same as in Example 5.

Comparative Example 5 PPS film-4 (OF measured in Edge and End directions was 0.09 and 0.10, respectively) was prepared by changing the stretching ratio to 4.5 times in the length and width directions by the method of Example 4. Then, a resin-impregnated fiber sheet (impregnated sheet-10) was prepared under the conditions of Example 1.

Example 6, Example 7 and Example 8 Three kinds of unstretched PPS films (PPS film-5 to PPM film 5 to 16 μm, 50 μm and 75 μm in thickness obtained by the method of Example 1 were used.
7) was obtained. Each of the films was heat-sealed with the fiber sheet-1 to obtain three kinds of impregnated sheets. The resin impregnated fiber sheet using the PPS film-8 is referred to as an impregnated sheet-11, an impregnated sheet-12, and an impregnated sheet-13 in this order. The conditions and method for heat fusion are the same as in Example 1.

Example 9 PPS film-1 and fiber sheet-1 were prepared by the method of Example 1.
The thermocompression bonding temperature of and was adjusted to 285 ° C. to obtain a resin-impregnated fiber sheet (impregnation sheet-14).

Comparative Example 6 By the method of Example 1, PPS film-1 and fiber sheet-
The thermocompression bonding temperature with 1 was set to 270 ° C. to obtain a resin-impregnated fiber sheet (impregnation sheet-15).

Comparative Example 7 By the method of Example 5, a biaxially stretched PP film (PPS film-8) having a thickness of 75 μm was prepared.

Comparative Example 8 An unstretched PPS film (PPS film-9) having a thickness of 75 μm was prepared in the same manner as in Example 1.

Comparative Example 9 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 It laminated | stacked via Toray Co., Ltd. product. Adhesive is applied to the corona discharge treated surface of PPS film-1 by the gravure roll method.
0 μm (dry thickness) was applied and laminated on both surfaces of the fiber sheet-1. The drying conditions for the adhesive are 100 ℃ and 3
The laminating conditions were a heating roll pressing method at a temperature of 120 ° C. and a pressing pressure of 3 kg / cm 2. Further 150
It was heat-cured at a temperature of ° C for 2 hours (laminate-1).

The evaluation results of Examples and Comparative Examples are shown in Tables 1, 2 and 3.

The resin-impregnated fiber sheet of the present invention has heat resistance,
It is a base material that has various properties such as thermal dimensional stability (low temperature dependency) and mechanical properties, and is well-balanced and has excellent through-hole processability and heat fusion processability.

Examples 1 to 9 and Comparative Examples 1 to 6
The characteristics of the respective impregnated sheets of are compared. Examples 1 to 9
The sheet of the present invention up to the present invention has the crystal structure referred to in the present invention within the range of the requirements of the present invention, and achieves the object of the present invention. When the PPS unstretched film was used to manufacture the resin-impregnated fiber sheet of the present invention from Examples 1 to 4 and Comparative Examples 1 to 3, when the relative crystallization index was large and the residual crystallization rate was small. If the mechanical properties and the heat-sealing properties are not satisfied, conversely the relative crystallization index is small and the residual crystallization rate is large, problems arise in heat resistance and thermal dimensional stability. Further, it can be seen that ACS (fine crystal size) influences mechanical properties. The above properties change depending on the Tcc of the unstretched film used and the production conditions, and the object cannot be achieved unless the crystal structure referred to in the present invention is within the range of the requirements of the present invention.

Comparative Example 1 has a low residual crystallization rate and a high heat fusion property, and the impregnated sheet of Comparative Example 2 has a large relative crystallization index and ACS and has a problem in mechanical properties. In Comparative Example 3, the relative crystallization index is low, and conversely, the residual crystallization rate is high and the thermal dimensional stability is high.
There is a problem with heat resistance.

In Example 5, Comparative Example 4 and Comparative Example 5, an impregnated sheet was prepared using a PPS stretched film.
The degree of orientation of the film used and the production conditions are the decisive factors for achieving the object of the present invention. That is, as in Comparative Example 4, when the temperature for thermocompression bonding of the film and the fiber sheet is low, the crystallization index is high, and conversely, the residual crystallization rate is low and the mechanical properties are
The heat fusion property does not reach the target level. Further, in Comparative Example 5, since the degree of orientation of the film used is too high, ACS tends to be large and mechanical properties tend to be low. Furthermore, in both cases, the degree of orientation of the resin layer of the impregnated sheet is high (the OF is low), so the thermal dimensional stability is poor. It is understood that the OF of the resin layer of the impregnated sheet is preferably 0.7 or more in each direction in terms of thermal dimensional stability.

Further, from Example 9, Comparative Example 4 and Comparative Example 6, it can be seen that the resin impregnation rate of 85% or more in the present invention is effective in terms of through hole processability.

From Examples 6 to 8, it is understood that the ratio of the resin layer to the fiber layer of the resin-impregnated fiber sheet of the present invention is preferably 2.5 or less in terms of thermal dimensional stability. However, if the ratio is made too small, the roughness of the surface becomes large and it becomes difficult to process a precision circuit. Therefore, it can be said that 0.25 to 2.5 is the optimum range.

Also, a PPS biaxially stretched film of Comparative Example 7,
The PPS unstretched film alone of Comparative Example 8 does not achieve the object of the present invention in terms of thermal dimensional stability and heat resistance.

The laminate of Comparative Example 9 is the laminate of the base materials of Example 1 using an adhesive. In addition to problems in heat resistance and thermal dimensional stability, resin is not impregnated in the fiber layer, so through-hole processability is poor. Also, the adhesive used affects the dielectric properties.

[0102]

[Table 1]

[Table 2]

[Table 3]

[0103]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned constitution, various characteristics such as heat resistance, thermal dimensional stability, low hygroscopicity, flame retardancy, mechanical characteristics, and high frequency characteristics can be balanced at a high level, and through holes, heat It was possible to obtain a high-performance insulating base material which is excellent in processability of the circuit board such as fusion processability and which is particularly suitable for a thinned circuit board.

Claims (3)

[Claims] 1. A sheet comprising a fiber sheet (A) impregnated with a resin composition (B) containing poly-p-phenylene sulfide as a main component, wherein the resin composition (B) has a resin impregnation rate of 80%. As described above, the relative crystallization index is 2.5 to 13.
0, the crystallite size is 50-100 angstroms,
The resin-impregnated fiber sheet, wherein the residual crystallization energy ΔHt is 20 to 80% of the crystallization energy ΔHq of the resin composition (B). 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.