JPH05310957A - Fiber sheet and circuit substrate using the same - Google Patents

Abstract

PURPOSE:To provide an insulating substrate utilizing the excellent high frequency characteristics, low hygroscopicity and flame retardancy of polyphenylene sulfide, excellent in the heat resistance and processability for circuit substrates, and suitable for the circuit substrates requiring the high speed treatments and high frequency treatments of signals, and to provide the circuit substrate (including multi-layer circuit substrates). CONSTITUTION:The fiber sheet having a thermal shrinkage of <=1.0% at 250 deg.C comprises (A) fibrous material having a dielectric constant of <=5.0 at the frequency of 1 mega Heltz and a dielectric loss of <=0.02 and (B) a resin composition containing polyphenylene sulfide as a main component, and the circuit substrate disposing an electric circuit on at least one surface of the fiber sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber sheet and a circuit board using the same, more specifically, a fiber sheet comprising a fibrous material having excellent dielectric properties and a resin composition containing polyphenylene sulfide as a main component, The present invention relates to a circuit board using the fiber sheet as a base material.

[0002]

2. Description of the Related Art In the fields of electric and electronic parts, there is an increasing demand for an insulating base material having excellent heat resistance and high frequency characteristics from the viewpoint of miniaturization and high functionality of equipment. In particular, circuit boards are required to be capable of high-speed signal processing and to support high frequencies in order to meet the information age, and it is strongly desired that circuit boards have excellent high-frequency characteristics.

As a base material in this field, a base material in which glass cloth is impregnated with an epoxy resin (hereinafter sometimes abbreviated as glass epoxy), a polyimide film, a fluorine-based film and a base material in which glass cloth is impregnated with a fluorine-based resin. and so on. Furthermore, poly-p-phenylene sulfide (hereinafter referred to as PPS
May be abbreviated. The unstretched sheet and the biaxially oriented film of (1) have recently attracted particular attention. In addition, biaxially oriented poly-p-phenylene sulfide film (hereinafter PPS
It may be abbreviated as a film. A laminated film or a laminated body using (1) is obtained by laminating (1) an aromatic polyamide fiber sheet with an adhesive (JP-A-60-63).
158), (2) a laminate of PPS with a fibrous material (Japanese Patent Laid-Open No. 63-237949), and (3) a laminated film with a fluorine-based film for the purpose of improving the impact resistance of the PPS film. (Japanese Patent Laid-Open No. 62-292432),
(4) A laminate with a fibrous material that is infusible at a temperature of 300 ° C. and has a thermal expansion coefficient at a temperature of 150 ° C. of 50 × 10 ^-6 ° C. ^-1 or less (Japanese Patent Laid-Open No. 63-63158). ), Etc. are known.

[0004]

However, the above films, laminated films and laminated bodies have the following problems, respectively. Glass epoxy has poor high-frequency characteristics and has a problem of hygroscopicity, so that there is a problem that the dielectric characteristics are further deteriorated when the frequency is increased. Polyimide films have excellent heat resistance, but are inferior in high frequency characteristics and moisture absorption characteristics. Further, a fluorine-based film or a base material in which a glass cloth is impregnated with a fluororesin has poor adhesiveness, and there is a problem that it is difficult to apply paste or plating when printing during circuit formation or laminating metal foil or through-hole machining. ..

On the other hand, an unstretched sheet of PPS satisfies characteristics such as thermal dimensional stability, low hygroscopicity, flame retardancy, and high frequency characteristics, but has a lower heat resistance temperature than a biaxially oriented film (glass transition). If it exceeds the point, it is likely to be thermally deformed.), And as the number of processing steps 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, but there is a problem that thermal deformation easily occurs when heat is rapidly applied as in soldering. ..

Further, since the PPS film undergoes 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. Although processing for reducing the heat shrinkage rate is performed by annealing or the like, if the heat shrinkage rate at 250 ° C. is set to 1% or less, the flatness of the film is significantly deteriorated. Further, there is a problem that the laminated circuit board is easily torn during processing of through holes.

In addition, the heat resistance of the adhesive sheet laminated with the aromatic polyamide fiber sheet of the above item (1) via an adhesive is improved, but the heat resistance of the adhesive adversely affects the base material (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. Furthermore, the conductive paste may soak in during through hole processing.
The plating is difficult to ride, and it is not possible to process through holes.

The laminate with the PPS fibrous material of the above item (2) has improved mechanical properties, but does not have improved heat resistance and thermal dimensional change rate.

The laminated film with the fluorine-based film of the above item (3) has excellent dielectric properties and improved mechanical properties, but the conductive paste and plating at the time of through-holes are difficult to ride, and there is a problem in through-hole processability. ..

The laminate of item (4) is a fibrous material and PP.
The adhesive strength with the S film is weak, and it easily peels off when a force such as bending is applied. In addition, there is a problem in through hole processability.

Although it is considered that the PPS resin is impregnated with a fibrous material such as glass cloth, there is a problem that the excellent dielectric properties and moisture absorption properties, which are the features of PPS, are deteriorated.

[0012]

DISCLOSURE OF THE INVENTION The present invention takes advantage of PPS's excellent high-frequency characteristics, low hygroscopicity, and flame retardancy, and is excellent in heat resistance and processability as a circuit board. Insulation base material suitable for circuit boards that require
And a circuit board using the same (including a multilayer circuit board)
The purpose is to provide.

[0013]

The fiber sheet of the present invention for this purpose is a fibrous material (A) having a dielectric constant of 5.0 or less and a dielectric loss of 0.02 or less at a frequency of 1 MHz and polyphenylene. A fiber sheet comprising a resin composition (B) containing sulfide as a main component, which is 250 ° C.
Of which the heat shrinkage ratio is 1.0% or less. The circuit board of the present invention is manufactured by providing an electric circuit on at least one surface of this fiber sheet.

The fibrous material (A) in the present invention is a thin leaf body composed of an aggregate of fibers, and includes a cloth,
Non-woven fabric, cloth, felt, paper, etc., thickness 5-50
The thickness is 0 μm (preferably 10 to 300 μm).
Further, the dielectric constant and the dielectric loss of the composition of the fibrous material at a frequency of 1 MHz are 5.0 or less and 0.0, respectively.
It should be 2 or less (preferably a dielectric constant of 4.0 or less and a dielectric loss of 0.01 or less). When the permittivity and the dielectric loss exceed the above-mentioned values, not only the excellent dielectric characteristics of PPS are deteriorated, but also it cannot be applied as a substrate for high-speed signal processing and high frequency. The melting point or softening point of the fibrous material is preferably 270 ° C or higher. Examples of the base material of the fibrous material include inorganic materials such as glass, organic materials such as fluorine, aramid, polyimide, liquid crystal polymer, and a mixture or laminate of two or more kinds thereof. Here, the dielectric constant is the relation between the electric flux density (D) and the electric field (E), D =
It is represented by εE and refers to ε at that time. Further, the dielectric loss is a phenomenon in which energy is lost as heat when an AC electric field is applied to the dielectric, or the amount thereof. Further, the fibrous material may be processed such as easy adhesion and coloring.

Particularly, the fibrous material used in the present invention is a non-woven fabric made of a resin composition containing a fluororesin as a main component, and a cloth is a balance of various characteristics such as high frequency characteristics, low hygroscopicity and heat resistance which are the objects of the present invention. And it is preferable in terms of processability. Examples thereof include, for example, polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer and resin compositions thereof. Examples include cloth and non-woven fabric. Here, "having a fluororesin as a main component" means that 50% by weight or more of the resin composition is a fluororesin, and if the amount of the fluororesin is 50% by weight or less, high frequency characteristics, moisture absorption characteristics and the like are deteriorated. Other polymers, inorganic additives, etc. may be contained as long as the remaining amount is 50% by weight or less. Further, it may be mixed and laminated with other fibers.

In the present invention, poly-p-phenylene sulfide (hereinafter sometimes abbreviated as PPS) means
70 mol% or more of the repeating unit (preferably 80 mol%
The above) refers to a polymer composed of the structural units represented by the structural formula 1. 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.

[0017]

[Chemical 1]

In the above PPS, the repeating unit of 30
If it is less than mol%, preferably less than 20 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, a resin composition containing poly-p-phenylene sulfide as a main component (hereinafter sometimes abbreviated as PPS composition) means a composition containing 60% by weight or more of poly-p-phenylene sulfide. Say. PPS
If its content is less than 60% by weight, the mechanical properties, heat resistance, dielectric properties, etc. of the fiber sheet comprising 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. Further, the melt viscosity of the PPS composition is 100 to 50000 poise (more preferably 5 at a temperature of 300 ° C. and a shear rate of 200 sec ⁻¹ ).
The range of 00 to 20000 poise) is preferable from the viewpoint of workability of lamination.

The fibrous sheet in the present invention comprises the above-mentioned fibrous material (A) and the PPS resin composition (B). In this case, even if A and B are simply laminated,
Part or all of A may be impregnated with B, but part or all of A may be impregnated with B more easily to achieve the object of the present invention. Here, the impregnation refers to a state in which a resin has entered the surroundings of the elemental fibers constituting the fibrous material and has adhered and solidified with the elemental fibers. The impregnated state can be measured, for example, by the degree of ink penetration. It is particularly preferable that the fiber sheet of the present invention has an ink impregnation degree described below of 5.0 or less (more preferably 3.0 or less). If the degree of penetration exceeds 5.0, the dielectric properties will deteriorate due to the influence of moisture, etc., and the workability of through holes will become difficult, making it difficult to achieve the object of the present invention. Here, the ink impregnation degree means that when the magic ink is immersed in the cross-sectional direction (thickness direction) of the fiber sheet for 1 minute, the ink permeates the inside, but the permeated length (from the end face of the fiber sheet The longest distance reached by the ink) is a value represented by the length (mm) measured from the surface of the fiber sheet, and is a parameter representing the degree of impregnation of the fiber sheet.

The ratio of the (A) layer to the (B) layer of the fiber sheet is not particularly limited, but when the thickness of each layer is measured from the cross section of the fiber sheet with a microscope or the like, the (B) single layer The surface roughness is in the range of 0.1 to 3 (more preferably 0.25 to 2.5) in the ratio (b / a) of the thickness (b) and the thickness (a) of the fibrous material layer impregnated with PPS. It is preferable in terms of (circuit forming processability), impregnation property, dielectric property, heat resistance, thermal dimensional stability and the like. Further, the (a) layer of the fiber sheet of the present invention does not necessarily have to be present in the center of the fiber sheet in the thickness direction, and may be at a shifted position. Further, two or more layers having the above structure may be laminated to form a multilayer.

Further, the fiber sheet of the present invention must have a heat shrinkage ratio at 250 ° C. of 1.0% or less. If the heat shrinkage ratio exceeds 1.0%, a circuit shift is likely to occur at the time of manufacturing the circuit board, and in the case of a multilayer circuit board, the position of the through hole tends to shift. Further, the solder may be deformed or warped during soldering. Here, the heat shrinkage is expressed as a percentage by dividing the dimensional change amount when aged at 250 ° C. for 30 minutes by the sample length before aging.
Further, the fiber sheet may be subjected to a treatment such as annealing (relax) for the purpose of suppressing the heat shrinkage rate.

The dielectric constant and the dielectric loss of the fiber sheet of the present invention at 1 MHz are 3.5 or less and 0.00, respectively.
5 or less and a moisture absorption rate of 0.1 or less (25 ° C., 75% R
H, 72 hours) is preferable for achieving the object of the present invention. The total thickness of the fiber sheet is 20 to 15
00 μm (more preferably 20 to 1000 μm, further preferably 20 to 700 μm) is preferable.

The fiber sheet of the present invention is particularly suitable for a base material of a circuit board (including a multilayer circuit board). The circuit board of the present invention is one in which an electric circuit is formed on at least one surface of the above fiber sheet. An electric circuit is a passage of electricity in which a conductor is patterned, and as a conductor,
A conductive paint containing a metal such as copper, aluminum or iron, or copper, silver or carbon is usually used. Moreover, electric and electronic components may be mounted on the electric circuit. Further, the circuit board may be laminated in two or more layers.

Next, a method for manufacturing the fiber sheet and the circuit board of the present invention will be described, but the method is not limited to this method. First, as the fibrous material used in the present invention, for example, one made of a fluorine-based resin composition, the fibers of the resin composition are made into a cloth by a well-known method such as plain weave, twill weave, and entangled weave.
Further, the non-woven fabric can be obtained by a known method such as a wet method, a dry method or a spun bond from the resin composition or the fiber thereof. Further, a treatment such as a calendar treatment may be performed to entangle the fibers.

The PPS used in the present invention is obtained by reacting alkyl 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-methylpyridone. In this case, in order to adjust the degree of polymerization, a so-called polymerization aid such as caustic alkali, carboxylic acid alkali metal salt or the like is added to give 230-28.
It is preferable to react at 0 ° C. The pressure of the polymerization system and the polymerization time are appropriately determined depending on the kind and amount of the auxiliary agent used and the desired degree of polymerization. The obtained granular or powdery polymer is washed with water and / or a solvent to separate a by-product salt, a polymerization aid, an unreacted monomer and the like.

Various methods can be used for impregnating a fibrous material with this polymer and laminating it, and the following three can be exemplified as typical methods. (1) A method for producing a fibrous sheet by thermocompression bonding a PPS sheet obtained by molding the above polymer into a non-stretched, non-oriented sheet to a fibrous material. In producing by the method, first, a method for producing an unstretched sheet of PPS will be described. The above PPS is supplied to a melt extruder typified by an extruder, heated to a temperature equal to or higher than the melting point of the polymer (more preferably in the range of 300 to 350 ° C.) and sufficiently kneaded, and then continuously fed from a slit die. And then rapidly cooled to a temperature below the glass transition point of PPS to obtain a substantially non-oriented PPS sheet. Next, overlay the PPS sheet and the fibrous material, and
Thermocompression bonding is performed with a heating roll press or a hot plate press at a temperature of 40 ° C. or higher (preferably 260 ° C. or higher) under a pressure of 1 to 30 kg / cm ² . Further, the fiber sheet is cooled through a cooling roll, a cooling plate, fresh air, water or the like for the purpose of maintaining the flatness. The thermocompression bonding temperature is 240 ° C
In the following, the impregnating property is poor and the dielectric properties, the workability of the through holes, etc. are deteriorated. The pressure during thermocompression bonding is 1 kg / cm.
^If it is less than ² , impregnation is poor, and if it exceeds 30 kg / cm ² , the flatness of the fiber sheet tends to deteriorate. When the fibrous material and the PPS sheet are thermocompression bonded, the fibrous material and P
2 layers of PS sheet, PPS sheet, fibrous material,
The three layers of the PPS sheet may be laminated in this order, but the latter is preferable because of the impregnation property. The thickness ratio (B / A) of the fibrous material (A) and the PPS sheet (B) before thermocompression bonding is preferably in the range of 0.2 to 5.0 in order to achieve the object of the present invention. In addition, the multilayered laminate of the present invention can be laminated by using the above-mentioned two-layer body and / or three-layer body as a basic structure.

(2) A method in which PPS is extruded from a slit-shaped die and pressure-bonded while laminating it on the fibrous material below, or thermocompression-bonding after that. The conditions for thermocompression bonding in this method are the same as in method (1).

(3) A method for producing a fibrous sheet by thermocompression bonding a biaxially oriented PPS film to a fibrous material. In producing by the method, first, a method for producing a biaxially oriented PPS film will be described. PP obtained by the method (1)
The S sheet is biaxially stretched by a known method. For example, when the sequential biaxial stretching method is used, the stretching conditions are a stretching temperature of 90 to 120 ° C. and a stretching ratio of 2.0 both in the longitudinal direction and the transverse direction.
The range of up to 4.5 times is preferable. Then, heat treatment is performed if necessary. The tenter method is used as the heat treatment method. The heat treatment condition is usually carried out in the temperature range of 200 to 290 ° C. under a fixed length or a restricted shrinkage of 15% or less. In addition, both directions may be relaxed to improve the thermal dimensional stability of the film. The biaxially oriented PPS film thus obtained and the fibrous material are superposed on each other and heated at a temperature not lower than the melting point of PPS (preferably 285 to 350 ° C.) under a pressure of 1 to 30 kg / cm ^2. Thermocompression bonding with a roll press or hot plate press. Further, for the purpose of maintaining the flatness of the fiber sheet, it is cooled through a cooling roll, a cooling plate, fresh air, water and the like. The thermocompression bonding temperature is PP
If the melting point is less than S, impregnation is poor, and dielectric properties, through-hole processability, etc. are degraded. The pressure during thermocompression bonding is 1k.
If it is less than g / cm ² , impregnation is poor, and conversely 30 kg / c
If it exceeds m ² , the flatness of the fiber sheet tends to deteriorate. Further, when the fibrous material and the PPS sheet are thermocompression-bonded, there are two layers of the fibrous material and the PPS sheet, and three layers of the PPS sheet, the fibrous material and the PPS sheet may be superposed in this order. , The latter is preferable from the viewpoint of impregnation property.
In addition, the fibrous material (A) and the PPS sheet (B) before thermocompression bonding
The thickness ratio (B / A) is preferably in the range of 0.2 to 5.0 in order to achieve the object of the present invention. Further, the multilayered laminate of the present invention can be laminated by using the above-mentioned two-layer body and / or three-layer body as a basic structure.

Further, powdery, granular or pelletized PP
By directly contacting the S polymer with the fibrous material, the above (1) to
It is also possible to stack under the condition of (3). Furthermore, by impregnating the fibrous material with the PPS resin composition by the above-mentioned method or another method, and then polishing or etching the resin-impregnated material by a physical or chemical method,
It does not matter if the final product satisfies the constitution of the present invention and achieves the purpose.

Next, a method of manufacturing a circuit board based on the fiber sheet of the present invention will be described. On one side or both sides of the fiber sheet, a metal foil such as aluminum or copper is thermocompression-bonded or laminated with an adhesive, or a metal layer is laminated by a method such as a vacuum deposition method, a plating method, or a sputtering method on the above metal. Then, a desired circuit pattern is formed by etching with a ferric chloride aqueous solution or the like. In addition, a circuit pattern is formed by a method such as silk printing using a conductive paint containing silver, copper, carbon, etc., and the paint is cured by heat or ultraviolet rays as necessary. If necessary, stack the above circuit boards into a multilayer circuit board,
Through hole processing and mounting of electrical and electronic parts.

[Characteristic Evaluation Method] Next, the characteristic evaluation method and evaluation criteria used in the description of the present invention will be described. (1) Heat resistance A 2 cm square sample was floated in a solder bath set at a temperature of 260 ° C. and evaluated according to the following criteria. ◯: No change at all. Δ: Partly softened, deformed, peeled and wrinkled. Poor: Deformation or peeling such as waviness or bending on the entire surface, and the dimensional change rate of each layer is significantly different.

(2) Dielectric properties Dielectric constant and dielectric loss were measured at a frequency of 1 MHz.
(Measured according to JIS-C-6481.)

(3) 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 a circuit dislocation was observed with that not passed through the furnace.

(4) Circuit printability A circuit having a width of 200 μm (line width of 200 μm) is printed on the sample by silk printing with a conductive paint, and after drying, the state of the circuit is observed with a microscope and evaluated according to the following criteria. did. ◯: Almost no swelling of circuit width, variation of line width, and distortion. Δ: The circuit width is swollen, the line width is changed, and some distortion is observed. ×: There are many swollen circuit widths, changes in line width, and distorted parts.

(5) Through-hole property The through-hole portion of the sample processed by through-hole was observed with a microscope to examine the adhesion of the conductive paint.

(6) Permeation of Ink When magic ink (the ink portion of the magic) is brought into contact with the surface of the fiber sheet in the cross-sectional direction (thickness direction) for 3 seconds,
The ink permeates inside. The soaked length (the longest distance that the ink reached from the position where the magic ink came into contact) was expressed by the length (mm) measured from the surface of the sheet. The magic used was from Pentel Co. (oil character of Penterpen medium letter N50).

(7) Measurement of the thickness and the thickness ratio (b / a) of the impregnated layer (a) and the resin single layer (b) of the fiber sheet. A cross-sectional photograph of the laminate was taken with an electron microscope, and the fibrous material layer and The layer in which the fiber sheet was impregnated with the resin was (a) and the layer consisting of the resin was (b), and the thickness of each layer was determined from the photograph.

(8) Heat shrinkage ratio A certain direction of the sample is used as a reference direction, and the reference direction and the 90 ° direction of the reference direction are each cut into 100 mm × 10 mm, and the length in the longitudinal direction is accurately read by a microscope ( xm
m). Next, after aging for 30 minutes in a furnace (hot air system) heated to a temperature of 250 ° C., the above length is accurately measured (ymm). Calculate the heat shrinkage rate (%) in each direction by the following formula,
The value is shown in the direction of larger heat shrinkage. Thermal contraction rate (%) = [(xy) / x] × 100

(9) Moisture absorption rate The sample was vacuum dried at a temperature of 100 ° C. for 10 hours and then weighed (Qmg). The sample is aged for 72 hours under a humidity condition of 75% RH and 25 ° C., and then the weight is measured again (Rmg). The moisture absorption rate was calculated by the following formula. Moisture absorption rate (%) = [(R−Q) / Q] × 100

[0041]

EXAMPLES The present invention will now be described in detail with reference to examples. Example 1 (1) Preparation of fibrous material A monofilament (80 μm diameter) of polytetrafluoroethylene (hereinafter sometimes abbreviated as PTFE) was plain-woven and a cross sheet having a density of 42 (pieces / 25 mm) (thickness 1
50 μm) was prepared. The dielectric constant and dielectric loss at 1 MHz of the cloth composition are 1.5 and 6 × 1, respectively.
It was ^0-4 .

(2) Preparation of PPS sheet A composition in which 0.2% by weight of silica fine powder having an average particle size of 0.7 μm is uniformly dispersed in PPS (manufactured by Toray Phillips Petroleum Co., Ltd.) is used as an extrudate having a diameter of 40 mm. Melt at 310 ℃ with a ruder and filter with a 95% cut hole diameter 10μm filter using metal wire mesh, then length 400
mm, and a T-die having a linear lip with a gap of 0.5 mm, and extruded on a metal drum whose surface temperature was kept at 25 ° C. to obtain an unstretched and unoriented sheet of PPS having a thickness of 50 μm.

(3) Preparation of Fiber Sheet The above PPS sheet / fibrous material / PPS sheet were superposed in this order and impregnated by the hot plate pressing method to be laminated. The press conditions were a temperature of 290 ° C. and a pressure of 20 kg / cm ² . The thickness of the obtained fiber sheet was 210 μm. This fiber sheet is referred to as fiber sheet-1.

Example 2 (1) Preparation of Fibrous Material A PTFE non-woven fabric having a thickness of 120 μm and a density of 0.67 g / cm ³ (H9703 manufactured by Tomoegawa Paper Mill) was prepared. The dielectric constant and dielectric loss at 1 MHz of the nonwoven fabric composition were 1.2 and 5 × 10 ⁻⁴ , respectively.

(2) Preparation of fiber sheet PPS was extruded and laminated on both surfaces of the fibrous material under the conditions of Example 1 to obtain four types of fiber sheets having different thicknesses. Further, the fibrous sheet was hot pressed under the conditions of Example 1 to impregnate the fibrous material and the resin. The thickness of the obtained fiber sheet is 130 μm, 190 μm, 280 μm, 470 μm
And fiber sheets 2 to 5 respectively.

Example 3, Comparative Example 1 Glass cloth having a thickness of 60 μm (EPC0 manufactured by Arisawa Seisakusho)
50) was prepared, treated with a silane coupling agent, and then coated on the entire glass cloth using a dispersion containing PTFE having a particle diameter of about 5 μm. The coating method is a wet method. The obtained cloth had a dielectric constant of 1 MHz and a dielectric loss of 2.8 and 0.0018, respectively. This cloth was impregnated and laminated on both surfaces with a PPS film (a biaxially oriented film “Torelina” manufactured by Toray) having a thickness of 25 μm. The lamination method was the method of Example 1, and the conditions were a temperature of 300 ° C. and a temperature of 260 ° C. and a pressure of 20 kg / cm ² . The obtained fibrous sheets are designated as fibrous sheets-6 and 7, respectively.

Comparative Example 2 A glass cloth coated with a dispersion of a silicone resin under the conditions of Example 3 (dielectric constant of 1 MHz and dielectric loss of 3.5 and 0.55, respectively) was prepared in the same manner as in Example 3. The PPS film was impregnated and laminated. Stacking temperature is 300
℃. The obtained fiber sheet is referred to as a fiber sheet-8.

Comparative Example 3 A PPS film (Toray Co., Ltd.) was formed on both sides of the fibrous material of Example 2.
50 μm of a biaxially oriented film “Torelina”) was laminated with an epoxy adhesive (“Chemit epoxy” TE5920 Toray). The method of applying the adhesive is a gravure roll method, the thickness of the adhesive is 15 μm / one side, and the drying is 1
The temperature is 00 ° C. for 3 minutes. The stacking condition is 120
The pressing pressure was 3 kg / cm ² at a temperature of ° C. 1 more
It was heat-cured at a temperature of 50 ° C. for 2 hours (fiber sheet 9).

Comparative Example 4 A film of tetrafluoroethylene-hexafluoroporopylene copolymer having a thickness of 50 μm (“Toyofuron” Toray).
(Manufactured by Mitsui Chemicals, Inc.) was plasma-treated in Ar gas, and a PPS film (25 μm was laminated on both surfaces.
Thermal fusion was carried out at a temperature of 10 ° C. and a pressure of 10 kg / cm ² (Layer-1).

Comparative Example 5 Under the conditions of Example 1, a 100 μm thick PPS sheet was obtained. The sheet was heat treated at a temperature of 250 ° C. for 5 minutes (P
PS sheet-1).

Comparative Example 6 Toray "Torelina" type 3000 thickness 100 μm
Was prepared (PPS film-1).

(Evaluation of Examples and Comparative Examples) Examples 1 to 3,
Fiber sheets, laminates, PPS sheets, P of Comparative Examples 1 to 6
The results of the PS film evaluation are shown in Tables 1 and 2.

[0053]

[Table 1]

[0054]

[Table 2]

As shown in Tables 1 and 2, the fiber sheets of the present invention of Examples 1 to 3 do not deteriorate (rather improve) the dielectric properties and moisture absorption properties which are the characteristics of PPS. It has excellent heat resistance and thermal dimensional stability, and is a base material suitable for high-speed signal processing and circuit boards compatible with high frequencies. Further, there was no problem in the processability of the through hole and the printability of the circuit. Further, in order to improve the dielectric properties of the base material, which is the object of the present invention, it is important that the dielectric constant and the dielectric loss at a frequency of 1 MHz of the fibrous materials from Examples 1 to 3 and Comparative Example 2 are within the ranges referred to in the present invention. It turns out that

The ratio (b / a) between the thickness (a) of the fibrous material impregnated with PPS and the thickness (b) of the PPS resin simple substance from Example 2 is 0.1 to 3.0. The range is preferable in view of printability of the circuit due to the surface roughness of the fiber sheet, heat shrinkage, and dielectric properties.

Comparing the fiber sheet of Example 3 with the fiber sheet of Comparative Example 1, the fiber sheet of Comparative Example 1 has a low thermocompression bonding temperature.
The impregnation property with the fibrous material is insufficient, the rate of thermal dimensional change cannot be suppressed, the processability of through holes (the degree of ink penetration is large) is poor, and the dielectric properties and moisture absorption properties are degraded.

Since the fibrous sheet of Comparative Example 2 has poor dielectric properties (dielectric loss) of the fibrous material used, the dielectric properties of the resulting fibrous sheet cannot achieve the object of the present invention. Comparative Example 3
Since the fibrous sheet of (1) is laminated via an adhesive, the adhesive reduces heat resistance, dielectric properties, moisture absorption properties, and the like. Since the laminate of Comparative Example 4 uses a film instead of a fibrous material, the effect of suppressing the heat shrinkage is less than that of the fibrous material, and a fluorine-based resin sheet layer is used for processing through holes. The poor adhesion of the product affects the conductive paste and the like. The PPS sheet of Comparative Example 5 has poor heat resistance, and the PPS film of Comparative Example 6 has a large thermal dimensional change rate.

Example 4 An electric circuit was patterned on one side of the fiber sheets of Examples 1 to 3 by a silk screen printing method using a conductive paint containing silver.
It was cured for 10 minutes at a temperature of ° C. Further, the circuit board was subjected to through-hole processing with a conductive paint to obtain a three-layer laminated circuit board (through-hole diameter: 200 μm). None of the circuit boards was deformed by soldering at 260 ° C., and there was no deviation of the circuit and the through holes. In addition, we performed high-speed signal processing and simulation for high frequencies.
Which circuit board has achieved the object of the invention.

Comparative Example 7 An electric circuit was provided on one side of the fiber sheet, laminate, PPS sheet, and PPS film of Comparative Examples 1 to 6 under the conditions of Example 4 to obtain 6 types of circuit boards. In the case of using the fiber sheets of Comparative Examples 1 and 3, the paste permeates into the sheet during the processing of the through holes, and the workability of the through holes is poor. In addition, misalignment of the circuit and through hole occurred.
In Comparative Example 4, the adhesion of the conductive paste in the through hole processing is poor in the fluorine-based resin film layer in the center layer of the laminate, and the through hole processability is poor. The one using the PPS sheet of Comparative Example 5 has a problem in solder heat resistance, and the one using the PPS film of Comparative Example 6 has a large heat shrinkage ratio.
The circuit and the through hole were misaligned. The one using the fiber sheet of Comparative Example 2 has no problem in solder heat resistance, through-hole processability, circuit, and through-hole deviation, but achieves the object of the present invention by high-speed signal processing and high-frequency simulation. I didn't.

[0061]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned constitution, it becomes a material in which high-frequency characteristics, moisture absorption characteristics, heat resistance, dimensional stability (heat, humidity) and the like are highly dimensionally balanced, and the signal which has recently been required particularly It is suitable for high-speed processing and high-frequency compatible circuit boards.

The fiber sheet of the present invention can be used for insulating materials such as transformers and motors, cable covering materials, heat-resistant adhesive tapes, prepreg base materials, heat-resistant labels, speaker base materials, electromagnetic waves, etc., in addition to circuit boards and laminated circuit boards. It is also most suitable as a shield base material. Further, another material (metal, organic or inorganic sheet) is laminated on at least one surface of the fiber sheet of the present invention, or another resin or coating agent is applied,
It may be molded. Further, the fiber sheet of the present invention may be oxidatively crosslinked with heat, ultraviolet rays or the like.

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Claims (4)

[Claims] 1. A fibrous material (A) having a dielectric constant of 5.0 or less and a dielectric loss of 0.02 or less at a frequency of 1 megahertz, and a resin composition (B) containing polyphenylene sulfide as a main component. Fiber sheet, 250 ° C
The heat shrinkage rate of the fiber sheet is 1.0% or less. 2. The fiber sheet according to claim 1, wherein the fibrous material (A) is a non-woven fabric made of a resin composition containing a fluororesin as a main component. 3. The fiber sheet according to claim 1, wherein the fibrous material (A) is a cloth made of a resin composition containing a fluororesin as a main component. 4. A circuit board comprising an electric circuit provided on at least one surface of the fiber sheet according to any one of claims 1 to 3.