JPH0192233A - Resin impregnated sheet - Google Patents

Abstract

PURPOSE:To obtain the title sheet having both excellent heat-resistant dimension al stability and water vapor-resistant dimensional stability, by impregnating aromatic polyamide yarn having specific physical properties with a resin. CONSTITUTION:Aromatic polyamide yarn having <=-1X10<-6>/ deg.C temperature linear thermal coefficient of expansion alphaTf, <=-2X10<-6>%RH humidity linear thermal coefficient of expansion, >=7,000kg/cm<2> modulus in tension Ef and <=2wt.% equilibrium water content Ew is impregnated with a resin to give the aimed sheet having <=10X10<-6>/ deg.C temperature linear thermal coefficient of expansion in the plane direction alphaTc and <=10X10<-6>/ deg.C humidity thermal coefficient of expansion in the plane direction alphaHC. Yarn obtained by sufficiently drawing a totally aromatic polyether amide copolymer to highly orientate the molecule is preferable as the totally aromatic polyether amide copolymer. A polyfunctional epoxy specific is preferable as the resin to be impregnated.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a sheet made of aromatic polyamide fibers and a resin and having excellent heat resistance, dimensional stability, and moisture resistance dimensional stability.

<Prior art> Sheets made of aromatic polyamide fibers impregnated with resin have good heat resistance and have been used for various purposes. For example, polymetaphenylene isophthalamide fibers (registered trademark Conex) : Teijin ■) and polyparaphenylene terephthalamide fiber (registered trademark Geppler ■4)
9. Sheets made of woven fabrics, non-woven fabrics, or paper impregnated with epoxy resin, polyimide resin, etc. made of Kevlar (29) (manufactured by DuPont) are being used as insulating base materials for @-clad laminates because of their excellent heat resistance. However, sheets made of polymetaphenylene isophthalamide fibers and resin are poor in both heat-resistant dimensional stability and 1FJf wet dimensional stability. A sheet made of a polyvalent phenylene terephthalamide fiber and a resin has excellent heat-resistant dimensional stability but poor moisture-resistant dimensional stability.

For example, Japanese Patent Publication No. 52-27189 discloses a sheet in which a nonwoven fabric made of aromatic polyamide fibers and polyester fibers is impregnated with a resin.

Japanese Patent Publication No. 56-1792 discloses the use of a sheet made of a resin-impregnated nonwoven fabric made of aromatic polyamide fibers, amylyl fibers, and drawn polyester fibers as an insulating base material.

Furthermore, JP-A-60-126400 discloses a paper-like material obtained by wet-processing a slurry of aromatic polyamide fibers and polyester fibers and then heat-pressing the slurry. It is disclosed that it can be applied.

JP-A-60-230312 discloses a flexible printed wiring board whose insulating base material is a sheet made of nonwoven fabric or paper containing aramid fibers as a main component and impregnated with a resin containing diallyl phthalate resin as a main component. .

Japanese Patent Publication No. 60-52937 discloses a copper-clad laminate whose base material is a sheet obtained by coating or impregnating an aromatic polyamide fiber cloth with an epoxy resin and/or a polyimide resin and drying it.

However, to date, no sheets made of these aromatic polyamide fibers and resins are known that are excellent in both heat-resistant dimensional stability and moisture-resistant dimensional stability.

<Object of the Invention> The present invention aims to overcome the conventional drawbacks of aromatic polyimide resins and sheets made of resin, and to provide a sheet which is excellent in both heat-resistant dimensional stability and moisture-resistant dimensional stability.

<Structure of the Invention> The resin-impregnated sheet of the present invention is a sheet formed by impregnating aromatic polyamide fibers with a resin, in which the aromatic polyamide fibers have the following properties (1) to (4).
) A resin-impregnated sheet characterized in that the sheet is made of fibers impregnated with a resin and has the following properties (5) to (6). 6
, /'C(2) Humidity linear expansion coefficient αHf≦−2,0x
lo”6 /%R1+(3) Tensile modulus Ef≧700
0kg/mm 2(4) Equilibrium moisture content Ew≦2.0
Weight% (5) Planar temperature linear expansion coefficient αTC≦10x 1
07°C (6) Surface direction humidity R fat swelling coefficient αHC≦10x
10'/'CJ.

The aromatic polyamide fiber mentioned here refers to the following repeating unit (I
) and/or (■).

HO I I+ +N Ar3-C+ -(ff) In the above formula, Ar1, Ar2, and Ar3 are substituted (wherein, X is -0-, S, C, CH2).

CH3 ■ -C- etc. ) Aromatic polyamide fibers containing CH3 A ri , A r2 , A r3 substituents on the aromatic ring, and 1° alkyl groups having 1 to 3 carbon atoms or halogen rings are preferred.

Furthermore, the repeating unit (I) is an aromatic boria residue shown in formula (I) (however, some of the hydrogen atoms directly bonded to the aromatic ring may be substituted with a halogen atom, a methyl group, a methoxy group, etc.). Fibers and/or highly molecularly oriented fully-stretched fully aromatic polyetheramide copolymer
Short fibers obtained by crushing and fibrillating the fibers are particularly preferred.

The single fiber fineness of the aromatic polyamide fiber is 0.1 to 10 deniers, preferably 0.3 to 5.0 deniers.

If it is less than 0.1 denier, there are many difficulties in terms of silk spinning technology (f
On the other hand, when the denier exceeds 10 denier, the aromatic polyamide fiber becomes impractical in terms of mechanical properties.6 Aromatic polyamide fibers may be in the form of long fibers, short fibers, or fibrillar bulbs. A mixture consisting of any combination may be used.

If the aromatic polyamide fiber is a long fiber, it can be used as a woven fabric.

Shapes such as knitted fabrics and non-woven fabrics, and non-woven fabrics in the case of short fibers.

It can take the form of dispersion in paper or resin, or any combination of long fibers and short fibers. In the case of short fibers, the cut length is preferably 1 to 60 mm, more preferably 2 to 60 mm.
If the cut length is less than 1 inch, the mechanical properties of the resin-impregnated sheet obtained will deteriorate, and if the cut length exceeds 60111111, the distribution of short fibers in the resin-impregnated sheet obtained will be poor, resulting in poor mechanical properties. Physical properties also deteriorate. Furthermore, in a bulb in which short fibers are fibrillated by mechanical shearing force, short fibers with a fineness that is difficult to spin can be obtained, and the distribution state of the short fibers in the resin-impregnated sheet can be further improved.

Furthermore, other fibers such as glass fiber, carbon fiber, polyetheretherketone fiber, polyetherimide fiber, wholly aromatic polyester fiber, polyphenylsulfide fiber, It is also possible to mix ceramic fiber etc.
In this case, the proportion of aromatic polyamide fibers in the total amount of constituent fibers is at least 60% by volume or more, preferably 70% by volume or more.

In the resin-impregnated sheets 1 to 1 of the present invention, various surface treatments may be applied to the aromatic polyamide fibers in order to improve adhesion with the resin, and the resin used has electrical properties 1, chemical resistance,
Solvent resistant, water resistant, heat resistant.

Select one with excellent adhesive properties.

Preferred resins include epoxy resin, polyfunctional epoxy compound, imide compound, polyfunctional isocyanate compound, phenol/formalin condensate, resorcinol/formalin wire mesh, melamine/formalin metal condensate, xylene/formalin condensate, alkylbenzene/formalin condensate,
Examples include unsaturated polyesters, polyfunctional allyl compounds (diallyl phthalate, triallyl(iso)cyanurate, etc.), polyfunctional (meth)acrylic compounds (including epoxy acrylate and urethane acrylate), imide compounds, and 2-amide imide compounds. Preferred are polyfunctional epoxy compounds, imide compounds, polyfunctional isocyanate compounds, phenol/formalin condensates, unsaturated polyesters, and diallylphthalate resins.

On the other hand, when improving adhesion and, if necessary, visibility, polyolefins (polyisobutylene, etc.), polyvinyls (polyvinyl chloride, polyacrylic esters, polyvinyl acetate, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, etc.) are used. ), rubber thread (polyisobutylene, polybutadiene, talolosulfonated polyethylene, polyepichlorohydrin, polychloroprene, etc.), silicone type, fluorine type, etc., or copolymers thereof are preferably mixed or reacted with the resin.

Also, resins are not limited to thermosetting resins, but include Teflon, polyether, and etherketone. Thermoplastic resins such as polyphenylene sulfide, polycarbonate, and polyether sulfone may also be used.

In addition, lubricants, adhesion promoters, R-fuel agents, stabilizers (antioxidants, etc.) may be added to the resin within a range that does not impair the performance of the present invention.

UV rescue materials (1 polymerization inhibitors, etc.), mold release agents, plating activators, and other inorganic or organic fillers (talc, etc.).

Titanium oxide, fluorine polymer fine particles, pigments, dyes.

Calcium carbide, etc.) may be added.

Normal impregnation and coating methods can be used to apply the resin to the aromatic polyamide fibers, but it is also possible to apply the resin to the aromatic polyamide fibers by, for example, layering a film or powder of the above resin on the aromatic polyamide fibers and then hot-pressing the aromatic polyamide fibers. You can also.

The present invention provides a sheet made of aromatic polyamide fibers impregnated with a resin, in which only aromatic polyamide fibers having a certain range of properties can achieve the high degree of heat-resistant dimensional stability and moisture-resistant dimensional stability required in the current innovative technology field. We have found that we can be satisfied at the same time.

When a product is used, changes in heat resistance and moisture resistance generally rarely occur independently, but often occur simultaneously.

Therefore, even if only heat-resistant dimensional stability or moisture-resistant dimensional stability is good, it is practically poor.The resin-impregnated sheet of the present invention has both heat-resistant dimensional stability and humidity-resistant dimensional stability of 12.
X 104/'C, 12X 10-'/%RH or less, which is good, and has extremely high dimensional stability against changes in temperature and humidity.

The humidity linear expansion coefficient αTf and the humidity linear expansion number αHf in the fiber axis direction of the aromatic polyamide fiber in the resin-impregnated sheet are −1,0×10”/’C and −2,0×10, respectively.
-8% RH or less.

αTf≧-1, Ox 10'6/'C Manaha αHf≧-
In the case of 2.0 x 104% RH, the reinforcing effect of the aromatic polyamide fibers in the resin-impregnated sheet cannot be said to be sufficient, resulting in poor heat-resistant dimensional stability or 1 liter wet dimensional stability. Furthermore, the aromatic polyamide fiber is characterized in that the tensile modulus Ef in the fiber axis direction is 7000 kg/nm2 or more. In this case, Ef refers to a value measured at room temperature using a constant speed extension type universal tensile tester. Efgano0
If it is less than 0 kf/rnm2, the reinforcing effect of the aromatic polyamide fibers placed in the resin-impregnated sheet will not be sufficient, resulting in poor heat-resistant dimensional stability and moisture-resistant dimensional stability.

The equilibrium moisture content of the aromatic polyamide fiber is 2.0% by weight or less. Equilibrium moisture content is 20°C 165%R based on JIS-L-1013 chemical fiber filament yarn test method.
This is the measured value of the moisture content of the fiber in an equilibrium state at H. Before measurement, wash the fibers with cyclohexane at 50°C for 30 minutes. If the equilibrium moisture content of the aromatic polyamide fiber exceeds 2.0% by weight, the swelling amount of the resin-impregnated sheet increases, impairing the dimensional stability of the sheet.
Further, when molding the resin-impregnated sheet, the amount of water escaping to the outside of the system increases, and voids occur at the interface between the fibers and the resin, resulting in defects in the internal structure of the sheets 1 to 1.

<Effects of the Invention> The resin-impregnated sheet of the present invention exhibits extremely small dimensional changes in the plane direction of the sheet due to changes in temperature and humidity. Therefore, the sheet does not warp or twist when used as a copper-clad laminate, for example. There aren't many. In addition, water absorption occurs during the wiring board manufacturing process.
Production accuracy is improved because dimensional changes due to drying etc. are small. Furthermore, during product use, short circuits do not occur due to dimensional changes in microcircuits, and electronic components such as leadless ceramic chip carriers (LCCC) and bare chips, which have extremely small humidity linear expansion coefficients, can be directly soldered. Even when installed, cracks will not occur in the solder area in the joint area due to changes in temperature or humidity.

Therefore, it can be used for a variety of applications that were not possible with conventional resin-impregnated sheets using aromatic polyamide fibers. For example, insulating base material for copper-clad laminates, surface material for hunk cores, quartz-based optical fiber gape, etc. It is suitable as a material for applications that require a high degree of heat and moisture resistance and dimensional accuracy, such as coating materials for parabolic antennas, aircraft, and space rockets.

<Examples> The present invention will be explained in more detail below with reference to Examples. The measurement method used in the examples is as follows.

(1) Using a humidity line expansion coefficient thermomechanical analyzer (TMA; Thermoflex type manufactured by Rigaku Denki Koku), the initial sample distance between the chucks is 20 degrees.
Measure with a width of 4.5 mm (in the case of fibers, use the width of multifilament), an initial load of 5 g, and a temperature increase/decrease rate of 10"C/min. After setting the sample, increase the temperature from room temperature to 200℃, and then 50℃.
From the second temperature rise curve when the temperature is lowered to
αTC and αTf of the humidity line expansion coefficient between C and C were calculated.

(2) Humidity linear expansion coefficient thermomechanical analyzer (TMA: manufactured by Shinku Riko ■ TMA -
3000 type) in a constant temperature bath, and the atmosphere was kept at 30℃.
, 30% RH to 30°C, 70% RH.The initial sample distance between the chucks was 15n.
un, the width is 5+pm (in the case of fibers, it is the width of the multifilament bundle). The initial load was 5 g. In each atmosphere, the sample was left sufficiently until there was no change in sample length. Humidity linear expansion 1 series αHC, αHf is 30°C 130%
Calculate based on formula (IV) from the curve when the temperature is raised from RH to 30°C 170% R21.

(3) Tensile modulus of aromatic polyamide fiber in the fiber axis direction: 30°C sample length 250. Tensile speed 10■/
It was calculated according to the following formula (V) from the strength difference between 1 and 2% of elongation in the strength and elongation curve when measured using an Instron 4C air chuck under the condition of min.

Ef (m/square 2): (Intensity difference between 1 and 2% (klr/mmz) l x 1
00...(V) Examples 1 to 3. Comparative Examples 1 to 4 The following samples were used as wholly aromatic polyamide fibers.

(1) Fully aromatic polyether amide fiber 1500 denier / 1000 filament registered trademark Technora ■ Manufactured by Ondai (!1) (2) Polyparaphenylene terephthalamide fiber 112
5 denier/1000 filament registered trademark Kevlar■
149 DuPont (3) Fully aromatic polyetheramide fiber 1500 denier/1000 filament 1)
Fiber with a low draw ratio even when spun with a polymer equivalent to (4) Polyparaphenylene terephthalamide fiber 150
0 denier/1000 filament registered trademark Kevlar■
29 Manufactured by DuPont (5) Polyparaphenylene terephthalamide fiber 1420 denier / 1000 filament registered trademark Kevlar ■ 49 Manufactured by DuPont (6) Polymetaphenylene isophthalamide fiber 1250 denier / 1000 filament registered trademark Cornex ■
The above six types of fiber bundles manufactured by Ondai ■ were washed in cyclohexane at 50°C for 30 minutes and then completely air-dried. Using a zero-order thermomechanical analyzer (TMA), the temperature linear expansion coefficient αTf and humidity line were measured. The expansion coefficient αHf was measured.

Next, the tensile modulus Ef of each fiber bundle was measured.

Next, Chiku I~U ■ fabric (200 denier/133 fil)
Uses raw yarn! @Dense 34 pieces/inch, width 34 pieces/inch, plain weave, 62r/rrf, thickness 0.1+nm) was prepared and washed in cyclohexane at 50°C for 30 minutes,
After removing the deposits, it was completely air-dried.

Next, the fiber bundles (after washing with cyclohexane) of (1) to (6) above were cut into 5 pieces and hand-papered using a Tarapy standard paper machine at a fiber weight of 62 g//.

After peeling the wet fiber sheet from the wire, it was transferred to a 40-mesh wire.

Next, bisphenol A/ebichlorohydrin type water-dispersible epoxy resin (trade name: DIC Fine EN-0270;
Dainippon Ink & Chemicals Co., Ltd.) water diluted solution (solid content concentration 2
% by weight) and after spraying onto the wet fiber sheet,
Further, dry curing was performed at 160° C. for 30 minutes in a heat dryer. The resin adhesion amount of the fiber paper was about 10% by weight.

Next, each of the above-mentioned fiber papers was passed between a pair of metal/cotton rolls whose surface was 150°C at a linear pressure of 250 kir/■.
Through calendering was performed at a speed of 1.8 m/min.

Next, bisphenol A/epichlorohydrin type brominated epoxy resin (Epicoat 5046-B 80. manufactured by Yuka Shell Epoxy ■) and phenol novolac type epoxy resin (Epicoat 154. manufactured by Yuka Shell Epoxy ■) 2
5 parts, 4,4°-diaminodiphenylsulfone (Ror
A varnish containing 15 parts of boron trifluoride monoethylamine complex (manufactured by Yuka Shell Epoxy L$1), and 60 parts of methyl ethyl getone was prepared.

After dipping the fabric and fiber paper into the varnish, the excess varnish was removed using a mangle, and the prepreg was prepared by drying with hot air at 140°C for 20 minutes.
One sheet of the prepreg was sandwiched between two sheets of JTC Foil (manufactured by Nippon Mining Gould Foil), and heated at 160°C using a hot press.
, 30kz/cl for 30 minutes, then 160°C, 50k
Curing was carried out at z/cl for 15 minutes. Further, it was taken out from the pot press and post-cured in a hot air dryer at 180°C for 2 hours. The obtained copper-clad laminate was immersed in an aqueous ferric chloride solution (42 Baumé, 40°C) to completely remove the copper foil, and then dried in a hot air dryer at 110°C for 3 hours to become absolutely dry.

Total resin volume fraction (V
R) was approximately 60%. αTC and αH of the sheet
C was measured using a thermomechanical analyzer (TMA). The obtained data are shown in Table 1.

Claims (1)

[Claims] In a sheet formed by impregnating aromatic polyamide fibers with a resin, the aromatic polyamide fibers have the following properties (1) to (4).
A resin-impregnated sheet characterized in that the sheet is a fiber impregnated with a resin and has the following properties (5) to (6) (1) Sensitivity linear expansion coefficient αTf≦−1.0×10＾− ^6
/℃ (2) Humidity linear expansion coefficient αHf≦-2.0×10^-^6
/%RH (3) Tensile modulus Ef≧7000kg/mm^2 (4) Equilibrium moisture content Ew≦2.0% by weight (5) Planar temperature linear expansion coefficient αTC≦10×10^-^
6/℃ (6) Surface direction humidity line expansion coefficient αHC≦10×10＾-＾
6/℃