JP2004290771A - Method for producing composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a coated cloth by coating a base material such as a fiber cloth with a molten resin or a resin varnish, which method is characterized in that the balance between the thickness of a coating film on the face and that of a coating film on the back, the thicknesses of the coating films, and the impregnability of substrate with resin are improved. <P>SOLUTION: The method for producing a composite material by coating the base material comprising a fiber cloth with the molten resin or the resin varnish diluted with a solvent comprises simultaneously coating both surfaces of the fiber cloth with a controlled amount of a coating liquid ejected from a pair of dies opposite to each other across a base material conveying passage. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Industrial applications]
The present invention relates to a method for producing a composite substrate, which is produced by applying a matrix resin such as a molten resin or a resin varnish diluted with a solvent to a long sheet made of a fiber cloth such as a glass cloth or a nonwoven fabric.
[0002]
[Prior art]
Conventionally, simultaneous double-sided coating, in which a resin cloth is impregnated into a fiber cloth such as a glass cloth to produce a coated cloth, requires a matrix resin reservoir to be installed in the substrate transport path and the substrate to be immersed in the liquid reservoir. In general, a dip method in which a coating liquid is adhered to both surfaces by a coating method is used. Two squeeze rolls arranged in parallel with a certain clearance are installed above the liquid storage tank, and the excess liquid is scraped off by the base material with the coating liquid passing through the gap between the rolls. Then, the amount of the applied liquid is measured and the thickness of the applied film is controlled. Usually, these coated cloths are produced as prepregs in a semi-cured state by a drying oven, and a substrate having the prepregs as a component is produced by pressure molding.
[0003]
It is said that low-viscosity coating liquids are more suitable than high-viscosity coating liquids with poor fluidity because it is difficult to immerse the substrate in the liquid in a dip type coating apparatus. I have. In addition, since there is no mechanism for controlling the balance between the front and back of the base material of the amount of the coating liquid, it has been difficult to uniformly apply the product to a product having a thick coating film. Therefore, in recent years, a double-side coating device using a die or the like has been developed, and a coating method by controlling the discharge amount has been adopted.
[0004]
[Problems to be solved by the invention]
When fabricating a composite substrate using a fiber cloth such as a glass cloth or a nonwoven fabric as a substrate, importance is given to resin impregnation between fibers as well as coating film thickness and coating surface smoothness. In particular, when a composite base material is used as a component of a display element substrate, it is necessary to perform a sufficient defoaming treatment so that air bubbles included in the base material become a fatal defect in product performance. In the dip coating method, the impregnation time is long because the resin is immersed in the liquid storage tank, and the impregnation property is relatively good. In the die-type coating, the resin can be impregnated only at the lip width of the die discharge port, so the impregnation time is very short, and the air inside the substrate loses the escape space by being applied from both sides of the substrate. It is considered that there is a high possibility that bubbles interposed between the fibers are not sufficiently removed.
[0005]
Although various developments have been made on a double-sided coating apparatus using a die, the above-mentioned problems have not been evident since the fiber cloth is not mainly used. For example, Patent Literature 1 describes a double-sided die system. However, control of the adaptive viscosity range of the coating solution and the amount of the coating solution adhering to the base material is the main purpose of development, and there is no particular problem regarding the impregnation property. Patent Document 2 describes the impregnating property for a net-like or porous metal sheet as an example. However, the impregnating property is not considered for a fiber cloth or the like since a fabric is described as a web of holes. Seem.
[0006]
Further, in Patent Document 3 using a nozzle having a shape relatively close to the die, a pre-impregnation mechanism for applying a solvent or a diluted resin varnish in advance is installed, and assistance for resin impregnation in the nozzle alone is provided. I'm doing it. The provision of such a pre-impregnation mechanism is a general method for improving the impregnating property, and is often used for a thick substrate even in the dipping method. In such a multi-stage impregnation method, the base material after impregnation must contact the guide roll without evaporating the solvent, so that the resin adheres to the roll surface and causes stickiness. In addition, squeeze rolls, etc. have a mechanism to remove the adhered resin such as a doctor bar, but it is spatially difficult to provide such a mechanism between the lips of the adjacent dies. This causes a problem that flattening cannot be performed. When using a solvent for pre-impregnation, the above-mentioned problems are unlikely to occur.However, compared to the dip method having a liquid circulation mechanism, the die method is a one-pass system in which the entire amount of the discharged liquid is adhered, so the base material is used. Is highly likely to cause unevenness in the resin amount.
[0007]
[Patent Document 1]
JP-A-10-314647
[Patent Document 2]
JP-A-10-34050
[Patent Document 2]
JP-A-2001-122992
[0008]
[Means for Solving the Problems]
That is, the present invention relates to (1) a method for producing a composite substrate produced by applying a resin varnish diluted with a molten resin or a solvent to a substrate made of a fiber cloth, wherein the composite substrate is opposed to both sides of a substrate transport path. A method for producing a composite substrate, comprising: simultaneously applying both sides to a fiber cloth by discharging a coating liquid while controlling the amount of the liquid from a pair of dies arranged in parallel.
(2) The composite base material manufacturing method according to (1), wherein the discharge direction of the pair of dies is inclined by 5 to 45 ° from a plane perpendicular to the base material transport path toward the base material discharge side.
(3) The composite base material production according to (2), wherein the lip portion of the upper die protrudes from the lip portion of the lower die, and its angle is inclined by 10 to 80 ° from a plane perpendicular to the base material transport path toward the base material loading side. Method.
(4) The method for producing a composite base material according to (1), (2) or (3), wherein the internal pressure of each die is discharged in a range of 6000 Pa or more to improve the impregnation property of the fiber cloth.
(5) A laminate comprising a composite substrate produced by the method of (1) to (3) as a component.
(6) A display element substrate comprising a composite substrate produced by the method of (1) to (3) as a constituent element.
It is.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of a double-sided simultaneous coating apparatus used in the present invention. The main components of the apparatus are a fiber cloth (substrate) (1) having a transport path in the longitudinal direction, a left die (2) and a right die (3) installed via the substrate transport path, and a substrate for the die. And a guide roll (13) for adjusting the position. Each die is composed of a combination of an upper die (5) and a lower die (12). A manifold (6) for storing a coating liquid between the upper die and the lower die, a land (7) serving as a flow path, and a discharge port are provided. An outlet lip (4) is formed. Also, for each die, an installation means (11) for setting the position of the die, an angle holding means (10) for setting an angle with respect to the substrate transport path, and an internal pressure measuring means (8) for measuring the internal pressure. And a liquid supply means (9) for supplying a coating liquid.
[0010]
Next, the principle of the present invention will be described. In FIG. 1, when the coating liquid is supplied into each die by the liquid supply means (9), it accumulates in a manifold portion (6) formed inside. The coating liquid is equalized in pressure distribution in the width direction in the manifold section, passes through the land section (7), is discharged from the lip section (4), and is applied to the surface of the base material (1).
[0011]
The base material carried into the application section (between the die lips) sandwiches air in the space between the fibers. When the discharge flow path (the direction of the land (7)) of the opposing die is perpendicular to the substrate transport path as shown in FIG. 2, the coating liquid discharged from the die lip is as shown by the arrow in FIG. Flows to In such a flow, the pressure distribution has a pressure peak on the side of the base material carrying the lip, and pressure is applied before the resin varnish permeates the base material (FIG. 2B). Therefore, when the resin permeates into the inside of the base material, the pressure is reduced, and the air inside the base material may remain inside. This tendency occurs remarkably when the discharge flow path of the die is inclined toward the substrate loading side.
[0012]
When the discharge flow path of the die is inclined toward the unloading side of the substrate, the coating liquid discharged from the die lip flows as indicated by the arrow in FIG. At this time, the coating liquid flows along the upper lip portion 4a, and the pressure distribution on the base material has a peak on the base material discharge side of the lip portion. At this time, since the coating liquid applied to the base material surface is pressurized as it penetrates into the base material, air bubbles interposed in the base material escape toward the base material loading side which is a low pressure side. Become. Therefore, there is no air bubble remaining inside the substrate, and it is possible to obtain a composite substrate having good impregnation.
[0013]
The resin used in the present invention is not particularly limited as long as it is used for a printed board or a substrate for a display element. However, from the viewpoint of heat resistance, Tg is preferably 150 ° C. or higher. Specific examples thereof include a cyanate resin, a thermosetting polyimide resin containing bismaleimide as a component, and a polyfunctional epoxy resin. Among them, a cyanate resin is particularly preferred. Examples of the cyanate resin include bisphenol dicyanate, di (4-cyanate-3,5-dimethylphenyl) methane, 4,4′-thiodiphenylcyanate, 2,2′-di (4-cyanatephenyl) hexafluoropropane, bisphenol E dicyanate, phenol / dicyclopentadiene copolymer cyanate, phenol novolak type cyanate resin, cresol novolak type cyanate resin, and / or a prepolymer thereof can be used. Above all, a novolak type cyanate resin and / or a prepolymer thereof are preferable because of high heat resistance and low linear expansion coefficient. The novolak type cyanate resin referred to herein is obtained by reacting any novolak resin with a cyanating reagent such as cyanogen halide, and is also obtained by heating the obtained resin to form a prepolymer. Can be done.
When the number average molecular weight of the novolak type cyanate resin in the present invention is less than 250, the crosslinking density is small, and the heat resistance and the coefficient of linear expansion may be inferior. When it exceeds 900, the crosslinking density is too high to complete the reaction. Since it may not be possible, the number is preferably 260 to 900, and more preferably 300 to 600. When a prepolymer is used, it is preferable that the novolak type cyanate resin having the above number average molecular weight is prepolymerized in a range that is soluble in a solvent such as methyl ethyl ketone, dimethylformamide, and cyclohexanone. The number average molecular weight in the present invention is determined by gel permeation chromatography in terms of polystyrene using an HLC-8120 GPC apparatus manufactured by Tosoh Corporation (columns used: SUPER H4000, SUPER H3000, SUPER H2000 × 2, eluent: THF). This is a value measured by a photographic report.
[0014]
The resin of the present invention, a cyanate resin, epoxy resin, phenol resin and other thermosetting resin, phenoxy resin, solvent-soluble polyimide resin, polyphenylene oxide, a resin in combination with one or more thermoplastic resins such as polyether sulfone It may be a composition. Particularly, the combined use of an epoxy resin is preferable because the water absorption can be reduced without deteriorating the chemical resistance. Examples of the epoxy resin to be used in combination include a phenol novolak type epoxy resin, a bisphenol A type epoxy resin, a dicyclopentadiene skeleton-containing epoxy resin, a naphthalene type epoxy resin, an arylalkylene type epoxy resin and the like, particularly a dicyclopentadiene skeleton epoxy resin, Naphthalene type epoxy resins and arylalkylene type epoxy resins are preferred. Here, the arylalkylene type epoxy resin refers to an epoxy resin having one or more arylalkylene groups in a repeating unit, and examples thereof include a xylylene type epoxy resin and a biphenylene dimethyl type epoxy resin.
The amount of the epoxy resin used in combination is preferably from 10 to 200 parts by weight based on 100 parts by weight of the cyanate resin. If the amount is less than 10 parts by weight, the effect of addition is difficult to be exhibited, and if it exceeds 200 parts by weight, the heat resistance of the cyanate resin may be impaired.
[0015]
When a cyanate resin is used in the present invention, it is preferable to add a curing accelerator to the resin composition. Known curing accelerators can be used. Examples thereof include organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octylate and cobalt octylate, triethylamine, tributylamine, diazabicyclo [2,2 , 2] tertiary amines such as octane, 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5 Imidazoles such as -hydroxymethylimidazole; phenol compounds such as phenol, bisphenol A, nonylphenol, and phenolic resins; organic acids; and mixtures thereof. Among them, phenolic resins are preferred in terms of curability and low ionic impurities. In the present invention, the compounding amount of the curing accelerator can be appropriately changed according to the use conditions. In the case of an organic metal salt, 0.001 to 1 part by weight, based on 100 parts by weight of the cyanate resin, of imidazoles In this case, the amount is preferably 0.05 to 10 parts by weight, and in the case of a phenol resin, the amount is preferably 0.5 to 50 parts by weight. If the amount is less than these ranges, curing tends to be slow.If the amount is more than these ranges, adverse effects such as reduction of the resin composition and prepreg life due to excessively accelerated curing, and peripheral contamination by volatile components derived from the curing accelerator are caused. It may come out.
[0016]
The fiber cloth used in the present invention is not particularly limited, and various inorganic or organic fiber cloths can be used. Specific examples thereof include E glass (alkali-free glass), S glass, D glass, quartz, glass cloth such as high dielectric constant glass, Kevlar (trade name: manufactured by DuPont Toray Kevlar), Technora (trade name: Of poly-p-phenylene phthalamide, poly-m-phenylene phthalamide, p-phenylene phthalamide and 3,4′-diphenyl ether phthalamide represented by Teijin Limited and Conex (trade name: Teijin Limited) Aromatic polyamide fiber cloth, aramid fiber cloth, polyester fiber cloth, nylon fiber cloth, polybenzazole fiber cloth, carbon fiber cloth, etc. made of a copolymer or the like can be used. Preferably, it is a glass cloth. The method of weaving the woven fabric filaments is not particularly limited, and may be a woven fabric having a structure such as plain weave, seaweed weave, satin weave, and twill weave, and is preferably plain weave. Further, it is not limited to a woven fabric, and may be a non-woven fabric. The thickness of the fiber is not particularly limited, but is preferably 30 to 150 μm.
[0017]
The fiber cloth used in the present invention is treated with various surface treating agents such as silane coupling agents, borane coupling agents, titanate coupling agents, and aluminum coupling agents for the purpose of improving the wettability with the resin component. However, the present invention is not limited to this.
[0018]
In the resin composition of the present invention, if necessary, components such as a lubricant, a heat-resistant agent, an antistatic agent, an ultraviolet absorber, a pigment and the like, a light stabilizer, and the like, as long as the effects of the present invention are not impaired. Can be.
A plastic substrate (laminate) can be obtained by using the prepreg of the present invention. One or more of the prepregs may be heat-molded to form a laminate having only a resin layer, or a copper foil or the like. By heat-forming together with the above-mentioned metal plate, a laminate comprising a metal layer and a resin layer can be obtained. Further, a part or all of the metal plate may be peeled off by etching treatment or the like.
[0019]
【Example】
Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.
(Example of device)
The following examples were performed using the glass fiber substrate manufacturing apparatus shown in FIG. A tapered lining was used for the angle holding means (10) of each die, and the die angle was adjusted by being sandwiched between the die and an installation table. The upper die has a structure in which only the tip lip portion can be replaced, and can be changed to a member having a changed lip tip angle.
(Example)
As shown in FIG. 4A, the die discharge angle was inclined by 15 ° from the plane perpendicular to the substrate transport path to the substrate carry-in side, and the die upper die lip used a member inclined by 60 ° from the same plane. . The resin varnish is prepared by dissolving 100 parts by weight of a novolak type cyanate resin (PT60, manufactured by Lonza Japan Co., Ltd., number average molecular weight: 560) and 2 parts by weight of a phenol novolak resin (PR-51714, manufactured by Sumitomo Durez) in methyl ethyl ketone at room temperature, and epoxysilane coupling. 1 part by weight of an agent (A-187 manufactured by Nippon Unicar) and 150 parts of spherical fused silica (SO-25R manufactured by Admatechs Co., Ltd., average particle size: 0.5 μm) are added, and the mixture is stirred for 10 minutes using a high-speed stirrer. Was used. The substrate used was a glass cloth (WEA-1080, manufactured by Nitto Boseki) having a thickness of 53 μm. The solvent was volatilized in a drying furnace for the coated base material to prepare a semi-cured prepreg.
The obtained prepreg had a good appearance. Microscopic observation of the cross section of the prepreg revealed that both the front and back resin layers on the glass cloth had a uniform thickness of 10 μm on both sides and a surface roughness Ra of 1.2 μm. In addition, when bubbles present inside were confirmed by microscopic observation using transmission illumination, bubbles having a diameter of 1 μm or less existed at a rate of 2 to 3 bubbles / 500 mm □.
(Comparative example)
Using the same resin varnish and substrate as in the examples, the dies were arranged as shown in FIG. When a composite substrate was prepared with this die arrangement, countless crater-like irregularities that seemed to be air bubble marks were generated on the surface of the coating immediately after coating. It is considered that the bubbles remaining inside the base material reached the resin surface and foamed, and it was considered that impregnation was not obtained with this arrangement.
[0020]
【The invention's effect】
In the method for producing a coated cloth in which a molten resin or a resin varnish is applied to a substrate such as a fiber cloth by the method of the present invention, the front-back balance of the applied film thickness, the applied film thickness, and the resin impregnating property to the substrate are improved. A manufacturing method can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a double-side coating apparatus using the present invention. FIG. 2 is a view showing a resin flow and a pressure distribution in a case where the apparatus is arranged perpendicularly to a substrate. FIG. FIG. 4 is a view showing a resin flow and a pressure distribution in a case where they are attached to each other. FIG. 4 is a view showing a die angle setting in the embodiment, and FIG. () Is a diagram showing the angle at which the lip of the upper die is projected from the lower lip.
FIG. 5 is a diagram showing an example of a comparative example of a double-sided coating apparatus, showing a case where a die is arranged offset from a base material.
[Explanation of symbols]
1 fiber cloth (base material)
2 Left die 3 Right die 4 Die lip 4a Upper die lip 4b Lower die lip 5 Die upper die 6 Die manifold 7 Die land 8 Die internal pressure measurement sensor 9 Coating liquid supply means 10 Angle setting means 11 Position setting means 12 Lower die 13 Guide roll for substrate position adjustment

Claims (6)

A method of manufacturing a composite base material by applying a resin varnish diluted with a molten resin or a solvent to a base material made of a fiber cloth, comprising a pair of dies arranged opposite to both sides of a base material transport path. A method for producing a composite base material, comprising simultaneously applying both sides to a fiber cloth by discharging a coating liquid while controlling a liquid amount. 2. The method according to claim 1, wherein a discharge direction of the pair of dies is inclined by 5 to 45 ° from a surface perpendicular to the substrate transport path to the substrate discharge side. 3. The method according to claim 2, wherein the lip of the upper die protrudes from the lip of the lower die, and the angle of the lip is inclined by 10 to 80 [deg.] From the plane perpendicular to the base material conveying path toward the base material loading side. The method for producing a composite base material according to any one of claims 1 to 3, wherein the impregnation property of the fiber cloth is improved by discharging the internal pressure of each die within a range of 6000 Pa or more. A laminate comprising a composite substrate produced by the method according to claim 1 as a component. A display element substrate comprising a composite substrate produced by the method according to claim 1 as a component.

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