JP2022121694A - Prepreg and composite material plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a prepreg that is excellent in handleability because of having an excellent drape property, and that can yield a formed article having an excellent mechanical property.

SOLUTION: Provided is a prepreg comprising a thermoplastic resin, and a carbon fiber cloth constructed of a warp carbon fiber bundle and a weft carbon fiber bundle, and in which the impregnation ratio of the thermoplastic resin into the carbon fiber bundle is 85% or more, the prepreg has portions in which the warp carbon fiber bundle and the weft carbon fiber bundle overlap each other, and there are voids in which the thermoplastic resin is not present, in the overlapping portion.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to prepregs and composite boards. More particularly, the present invention relates to a prepreg and a composite material plate, which are prepregs having excellent drape properties and thus excellent handleability, and from which molded articles having excellent mechanical properties can be produced.

In recent years, composite materials using carbon fibers as reinforcing fibers have been widely used in sports and leisure applications, industrial applications, the aerospace field, and the medical field, taking advantage of their high specific strength and specific rigidity. These composite materials are often molded via a prepreg, which is an intermediate base material in which reinforcing fibers are impregnated with a matrix resin.

In the past, thermosetting resins were used as matrix resins, but in recent years, the number of cases where thermoplastic resins are used as matrix resins is increasing, and thermoplastic resins are being used as matrix resins. By using, there is an advantage that a composite material having excellent impact resistance can be obtained and the molding time can be shortened (Patent Document 1).

When molding prepreg, which is an intermediate base material, into a molded product, the prepreg is preformed along a mold, etc., and then heated and pressurized. If the matrix resin is a thermoplastic resin, the prepreg is a rigid sheet. , and poor drapeability, making it difficult to preform into a complicated shape in some cases. In particular, when the reinforcing fibers of the prepreg are in the form of a woven fabric, the thickness of the prepreg increases and the rigidity of the prepreg increases, so drape properties tend to be extremely reduced.

Patent Literature 2 discloses a prepreg having excellent drapeability by partially impregnating reinforcing fibers with a thermoplastic resin and having a thermoplastic resin layer having unevenness on the prepreg surface. When the matrix resin is a thermosetting resin, the reinforcing fibers in the non-impregnated portion can be used as a degassing path for the air to be removed during molding to completely impregnate the reinforcing fibers with the matrix resin. However, it is possible (Patent Document 3). However, when the matrix resin is a thermoplastic resin, the viscosity of the resin when melted is much higher than that of a thermosetting resin. Therefore, it was necessary to maintain the pressure and temperature for a long time at higher pressure and temperature, and it was difficult to remove the voids in the non-impregnated portion of the prepreg during molding. That is, although the drape property of the prepreg is improved by partially impregnating the reinforcing fibers with the matrix resin, many voids remain in the molded article molded using this prepreg, and sufficient mechanical properties are exhibited. was difficult.

On the other hand, Patent Document 4 discloses that excellent impregnability is exhibited when reinforcing fibers aligned in one direction are impregnated using a polycarbonate resin having a specific molecular structure unit as a matrix resin. ing. However, the prepreg disclosed in Patent Document 4 has excellent impregnating properties of the matrix resin into the reinforcing fibers, so there is a problem that the unimpregnated portion is small and the drape property of the prepreg is lacking.

JP-A-9-155862 JP 2010-202824 A Japanese translation of PCT publication No. 2001-511827 JP 2014-133841 A

An object of the present invention is to provide a prepreg that has excellent drape properties, which makes it easy to handle, and from which a molded product having excellent mechanical properties can be produced.

・・・式（１）
（６） 前記炭素繊維織物の目付が２００～６５０ｇ／ｍ^２である、上記（１）から（５）のいずれかに記載のプリプレグ。
（７） 前記プリプレグのドレープ値が１～５ｃｍである、上記（１）から（６）のいずれかに記載のプリプレグ。
（８） 上記（１）から（６）のいずれかに記載のプリプレグを積層して一体化してなる炭素繊維複合材料板。
（９） 前記炭素繊維複合材料板の繊維体積含有率ＶｆおよびＪＩＳ Ｋ７０７４に準拠して測定される３点曲げ強度σ（ＭＰａ）が下記式（２）を満たす、上記（８）に記載の複合材料板。
４００（ＭＰａ） ≦ ４２×σ÷Ｖｆ ≦ １２００（ＭＰａ） ・・・式（２） As a result of intensive studies aimed at solving the above problems, the present inventors have found that the above problems can be solved by providing voids free of the thermoplastic resin in the overlapping portions of the warp and weft that constitute the carbon fiber fabric. , have completed the present invention. That is, the gist of the present invention resides in the following (1) to (9).
(1) A carbon fiber fabric comprising warp carbon fiber bundles and weft carbon fiber bundles and a thermoplastic resin, wherein the impregnation rate of the thermoplastic resin into the carbon fiber bundles is 85% or more, and the warp yarns and the carbon fiber bundles of the wefts overlap, and the overlapped portions have voids free of the thermoplastic resin.
(2) The prepreg according to (1) above, wherein the height of the voids in the direction perpendicular to the plane of the prepreg is 10 to 100 μm.
(3) The prepreg according to (1) or (2) above, wherein 80% or more of the total voids in the prepreg are present between the yarn carbon fiber bundles and the weft carbon fiber bundles.
(4) The prepreg according to any one of (1) to (3) above, wherein the thermoplastic resin is a polycarbonate resin.
(5) The prepreg according to (4) above, wherein the polycarbonate resin includes a unit structure derived from a compound represented by the following formula (1).

... formula (1)
(6) The prepreg according to any one of (1) to (5) above, wherein the carbon fiber fabric has a basis weight of 200 to 650 g/m ² .
(7) The prepreg according to any one of (1) to (6) above, wherein the prepreg has a drape value of 1 to 5 cm.
(8) A carbon fiber composite material plate formed by laminating and integrating the prepregs according to any one of (1) to (6) above.
(9) The composite according to (8) above, wherein the fiber volume content Vf of the carbon fiber composite material plate and the three-point bending strength σ (MPa) measured according to JIS K7074 satisfy the following formula (2): material board.
400 (MPa) ≤ 42 x σ/Vf ≤ 1200 (MPa) Expression (2)

The prepreg of the present invention has excellent drapeability, can be preformed into a complicated shape, has reduced voids in the molded product even when the prepreg is molded at a relatively low pressure, and has excellent mechanical properties. A molded product can be obtained.

The prepreg of the present invention comprises a carbon fiber fabric composed of warp carbon fiber bundles and weft carbon fiber bundles and a thermoplastic resin, and the impregnation rate of the thermoplastic resin into the carbon fiber bundles is 85% or more. , having a portion where the carbon fiber bundle of the warp and the carbon fiber bundle of the weft overlap, and a void without the thermoplastic resin in the overlapping portion (hereinafter "a void without a thermoplastic resin" is simply referred to as a "void" ) is a prepreg.

The prepreg of the present invention has a portion where the warp carbon fiber bundle and the weft carbon fiber bundle overlap, and has a gap in the overlapping portion (between the warp carbon fiber bundle and the weft carbon fiber bundle). Drapability is expressed. The gap preferably has a thickness (height) of 10 to 100 μm in the direction perpendicular to the plane of the prepreg. If the thickness is 10 μm or more, excellent drape properties are likely to be exhibited. If the thickness is 100 μm or less, voids are eliminated during the molding of the prepreg, which will be described later, and mechanical properties of the molded article after molding are likely to be exhibited. More preferably, the thickness (height) of the void prepreg in the direction perpendicular to the plane is 15 to 50 μm, still more preferably 20 to 40 μm, and most preferably 25 to 35 μm.

Prepregs with many voids and low impregnation are generally known to have excellent drape properties, but in general, once the voids in the reinforcing fiber bundles are closed, they cannot be removed during molding. It is also difficult. By setting the impregnation rate of the thermoplastic resin into the carbon fiber bundles in the prepreg of the present invention to be 85% or more, it is possible to suppress the deterioration of mechanical properties due to residual voids in the molded product, and to express excellent mechanical properties. It becomes easier to obtain a molded product.

In the prepreg of the present invention, voids are specifically aggregated between the warp carbon fiber bundles and the weft carbon fiber bundles, thereby ensuring the drapeability of the prepreg and existing between the warp carbon fiber bundles and the weft carbon fiber bundles. Since air can be easily removed during molding, voids do not remain in the molded product, and excellent mechanical properties can be exhibited. In order to obtain the effect of the present invention, it is preferable that 80% or more of all voids in the prepreg exist between the warp carbon fiber bundle and the weft carbon fiber bundle. It is more preferably 85% or more, still more preferably 90% or more, and most preferably 95% or more.

The form of the reinforcing fiber of the prepreg of the present invention is a carbon fiber fabric composed of carbon fiber bundles of threads and carbon fiber bundles of wefts. The weave pattern is not particularly limited, and includes plain weave, twill weave, and satin weave.

The prepreg of the present invention preferably has a reinforcing fiber basis weight of 50 to 800 g/m ² . When the reinforcing fiber basis weight of the prepreg is extremely low, it is necessary to laminate a large ^number of prepregs in order to obtain the desired thickness of the molded product, and the drape property is extremely increased, resulting in poor workability. If it is above, the prepreg which is excellent in workability will be obtained. ^On the other hand, when the reinforcing fiber basis weight is extremely large, the rigidity of the prepreg increases, and it becomes difficult to obtain the drape property, which is the effect of the present invention. be done. More preferably, the reinforcing fiber basis weight is 75-600 g/m ² , still more preferably 100-450 g/m ² , and most preferably 125-400 g/m ² .

The fiber volume content (Vf) of the prepreg of the present invention is 10 to 70 vol%, and when Vf is 10 vol% or more, the molded product has excellent mechanical properties. Moreover, when Vf is 70 vol% or less, it is excellent in drape property and shaping property. Vf is more preferably 15 to 60 vol%, still more preferably 20 to 55 vol%, most preferably 25 to 50 vol%. Note that the Vf value measured based on JIS K7075 is a value that varies depending on the amount of voids present in the prepreg base material, so in the method for producing a fiber-reinforced plastic of the present invention, the fiber volume content does not depend on the amount of voids present. Adopt rate.

The thermoplastic resins of the prepreg of the present invention include polyamide resins (nylon 6, nylon 66, nylon 12, nylon MXD6, etc.), polyolefin resins (low density polyethylene, high density polyethylene, polypropylene, etc.), modified polyolefin resins (modified polypropylene resin etc.), polyester resins (polyethylene terephthalate, polybutylene terephthalate, etc.), polycarbonate resins, polyamideimide resins, polyphenylene oxide resins, polysulfone resins, polyethersulfone resins, polyetheretherketone resins, polyetherimide resins, polystyrene resins, ABS resins , polyphenylene sulfide resin, liquid crystal polyester resin, copolymer of acrylonitrile and styrene, copolymer of nylon 6 and nylon 66, and the like. Modified polyolefin resins include, for example, resins obtained by modifying polyolefin resins with acids such as maleic acid (acid-modified polypropylene resins). Thermoplastic resins may be used singly or in combination of two or more, and two or more of them may be used as a polymer alloy. Among them, polycarbonate resin is preferable as the thermoplastic resin used for the prepreg of the present invention. More preferably, a polycarbonate resin containing at least a unit structure derived from a dihydroxy compound represented by the following formula (1) is preferred. The polycarbonate resin has excellent impregnation properties into carbon fiber bundles, and when impregnated into carbon fiber fabrics, voids tend to gather between the warp carbon fiber bundles and the weft carbon fiber bundles. It is suitable for realizing the form of the prepreg of the present invention.

・・・式（１）

... formula (1)

In the polycarbonate resin containing at least a unit structure derived from the dihydroxy compound represented by the above formula (1) of the present invention, a structural unit derived from the dihydroxy compound (1) with respect to all structural units derived from the dihydroxy compound constituted is preferably 90 mol % or less, more preferably 85 mol % or less, and most preferably 80 mol % or less. On the other hand, it is preferably 20 mol % or more, more preferably 30 mol % or more, and most preferably 40 mol % or more.

If the proportion of the structural unit derived from the dihydroxy compound (1) is too high, cracking may occur when the molded article is irradiated with Sunshine Carbon Arc, and the transparency may deteriorate and haze may increase. There is However, it is also possible to prevent this cracking by incorporating a light stabilizer described later, particularly a hindered amine light stabilizer in a predetermined amount. Although the details of the cause of such cracking are not clear, if the proportion of the structural unit derived from the dihydroxy compound (1) is too high, the surface of the resulting molded article deteriorates due to ultraviolet irradiation and is hydrolyzed, resulting in the formation of polycarbonate resin. It is thought that this is because the molecular weight decreases. However, as described above, it is possible to prevent cracking of the molded product by including a light stabilizer. Although the details of the cause are not clear, it is believed that the light stabilizer suppresses ultraviolet irradiation deterioration and hydrolysis of the surface of the molded product, and the molecular weight of the resin is less likely to decrease.

On the other hand, if the ratio of structural units derived from the dihydroxy compound (1) in the resin is too small, the heat resistance of the obtained molded article may be lowered.

Examples of the dihydroxy compound represented by the above general formula (1) include isosorbide, isomannide, and isoidet, which are in a stereoisomeric relationship, and these may be used singly or in combination of two or more. may be used.

The polycarbonate resin containing at least a unit structure derived from the dihydroxy compound represented by the formula (1) of the present invention is a dihydroxy compound other than the dihydroxy compound (1) (hereinafter referred to as "other dihydroxy compound" in some cases. ) may contain a structural unit derived from

Specific examples of dihydroxy compounds other than the above dihydroxy compound (1) include oxyalkylene glycols such as diethylene glycol, triethylene glycol and tetraethylene glycol; 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene; ,9-bis(4-(2-hydroxyethoxy)-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isopropylphenyl)fluorene, 9,9-bis(4 -(2-hydroxyethoxy)-3-isobutylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butylphenyl)fluorene, 9,9-bis(4-(2- hydroxyethoxy)-3-cyclohexylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3, 5-dimethylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butyl-6-methylphenyl)fluorene, 9,9-bis(4-(3-hydroxy-2, phenyl-substituted fluorenes such as 2-dimethylpropoxy)phenyl)fluorene, etc., compounds having an aromatic group in the side chain and an ether group bonded to the aromatic group in the main chain, represented by the following general formula (3) Compounds (cyclic ethers) having a cyclic ether structure such as spiroglycol are included.

Among these, diethylene glycol and triethylene glycol are preferable as the dihydroxy compound other than the dihydroxy compound (1) from the viewpoint of availability, handling, reactivity during polymerization, and hue of the resulting resin. A compound having a cyclic ether structure represented by formula (3) is preferred.

These may be used alone or in combination of two or more depending on the required performance of the resin to be obtained.

・・・式（３）

... formula (3)

Among these dihydroxy compounds, it is preferable to use a dihydroxy compound that does not have an aromatic ring structure from the viewpoint of the light resistance of the polycarbonate resin. Isosorbide, which is obtained by dehydration condensation of sorbitol obtained by dehydration, is most preferable from the standpoints of availability and ease of production, light resistance, optical properties, moldability, heat resistance, and carbon neutrality.

Further specific examples of other dihydroxy compounds include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol and 1,2-butanediol. , 1,5-heptanediol, 1,6-hexanediol and other aliphatic dihydroxy compounds, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecanediol, methanol, pentacyclopentadecanedimethanol, 2,6-decalindimethanol, 1,5-decalindimethanol, 2,3-decalindimethanol, 2,3-norbornanedimethanol, 2,5-norbornanedimethanol, 1, alicyclic dihydroxy compounds such as 3-adamantanedimethanol, 2,2-bis(4-hydroxyphenyl)propane [=bisphenol A], 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, 2,2-bis(4-hydroxy-(3,5-diphenyl)phenyl)propane, 2,2-bis(4-hydroxy- 3,5-dibromophenyl)propane, 2,2-bis(4-hydroxyphenyl)pentane, 2,4′-dihydroxy-diphenylmethane, bis(4-hydroxyphenyl)methane, bis(4-hydroxy-5-nitrophenyl ) methane, 1,1-bis(4-hydroxyphenyl)ethane, 3,3-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)sulfone , 2,4′-dihydroxydiphenyl sulfone, bis(4-hydroxyphenyl) sulfide, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dichlorodiphenyl ether, 9,9-bis(4- Aromatic bisphenols such as (2-hydroxyethoxy-2-methyl)phenyl)fluorene, 9,9-bis(4-hydroxyphenyl)fluorene and 9,9-bis(4-hydroxy-2-methylphenyl)fluorene mentioned. These may be used individually by 1 type, and may be used in combination of 2 or more type.

Among these, from the viewpoint of the light resistance of the resin, dihydroxy compounds having no aromatic ring structure in the molecular structure, that is, aliphatic dihydroxy compounds and/or alicyclic dihydroxy compounds are preferable. 1,3-propanediol, 1,4-butanediol and 1,6-hexanediol are preferable, and 1,4-cyclohexanedimethanol and tricyclodecanedimethanol are particularly preferable as alicyclic dihydroxy compounds.

By using these other dihydroxy compounds, it is possible to obtain effects such as improvement of resin flexibility and moldability, but if the content of structural units derived from other dihydroxy compounds is too high, , the ratio of the structural units derived from the dihydroxy compound (1) to the structural units derived from all the dihydroxy compounds in the resin is at least the lower limit value described above, since this may lead to a decrease in mechanical properties and a decrease in heat resistance. It is preferable to use so as to be

Further, when an alicyclic dihydroxy compound is used as the other dihydroxy compound, a structural unit derived from the dihydroxy compound represented by the general formula (1) in the polycarbonate resin and a structure derived from the alicyclic dihydroxy compound The ratio (mol %) to the units is preferably in the range of 99:1 to 30:70, more preferably 90:10 to 40:60 from the viewpoint of mechanical properties and heat resistance.

The dihydroxy compound (1) used for resin synthesis contains stabilizers such as reducing agents, antioxidants, oxygen scavengers, light stabilizers, antacids, pH stabilizers and thermal stabilizers. Since the dihydroxy compound of the present invention is susceptible to deterioration especially under acidic conditions, it preferably contains a basic stabilizer.

Basic stabilizers include hydroxides, carbonates, phosphates, phosphites, hypophosphites of group 1 or 2 metals in the long period periodic table (Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005) , borate, fatty acid salt, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, triethyl methylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide, butyl Basic ammonium compounds such as triphenylammonium hydroxide, 4-aminopyridine, 2-aminopyridine, N,N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4- Amine compounds such as methoxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, and aminoquinoline can be mentioned. Among them, sodium or potassium phosphates and phosphites are preferred because of their effects and ease of removal by distillation, which will be described later, and disodium hydrogen phosphate and disodium hydrogen phosphite are particularly preferred.

The content of these basic stabilizers in the dihydroxy compound (1) is not particularly limited. Since it may lead to modification of (1), it is usually 0.0001% to 1% by weight, preferably 0.001% to 0.1% by weight, based on the dihydroxy compound (1).

When the dihydroxy compound (1) containing these basic stabilizers is used as a raw material for producing a polycarbonate resin, the basic stabilizer itself becomes a polymerization catalyst, which not only makes it difficult to control the polymerization rate and quality, but also Since the hue is deteriorated and as a result the light resistance of the molded article is deteriorated, it is preferable to remove the basic stabilizer with an ion exchange resin or by distillation before using it as a raw material for producing a polycarbonate resin.

Since the dihydroxy compound (1) is easily oxidized by oxygen, it should be kept free of moisture during storage and production to prevent decomposition by oxygen. Handling is essential. For example, when isosorbide is oxidized, decomposition products such as formic acid may be generated. For this reason, when isosorbide containing these decomposition products is used as a raw material for producing a polycarbonate resin, the obtained polycarbonate resin and further the polycarbonate resin composition may be colored, and the physical properties may be significantly deteriorated. In addition, it may affect the polymerization reaction and may not yield a high-molecular-weight polymer.

In order to obtain the dihydroxy compound (1) free from the oxidative decomposition product and to remove the basic stabilizer, it is preferable to carry out purification by distillation. Distillation in this case may be simple distillation or continuous distillation, and is not particularly limited. As for distillation conditions, it is preferable to carry out distillation under reduced pressure in an inert gas atmosphere such as argon or nitrogen. ° C. or less is preferable.

In such distillation purification, the content of decomposition products such as formic acid in the dihydroxy compound (1) is 20 ppm by weight or less, preferably 10 ppm by weight or less, and particularly preferably 5 ppm by weight or less, thereby obtaining a dihydroxy compound ( When a dihydroxy compound containing 1) is used as a raw material for producing a polycarbonate resin, it is possible to produce a polycarbonate resin excellent in hue and heat stability without impairing polymerization reactivity. The content of decomposition products such as formic acid is measured by ion chromatography.

The polycarbonate resin containing at least a unit structure derived from the dihydroxy compound represented by the above formula (1) used in the present invention is obtained by polymerizing a dihydroxy compound containing the above-described dihydroxy compound (1) and a carbonic acid diester as raw materials by transesterification reaction. It can be obtained by condensation.

Carbonic acid diesters used in the reaction generally include those represented by the following general formula (4). These carbonic acid diesters may be used singly or in combination of two or more.

・・・式（４）

... formula (4)

In general formula (4), A ¹ and A ² are each a substituted or unsubstituted aliphatic group having 1 to 18 carbon atoms or a substituted or unsubstituted aromatic group, and A ¹ and A ² are They may be the same or different.

Examples of the carbonic acid diester represented by the general formula (4) (hereinafter sometimes referred to as "carbonic acid diester (3)") include substituted diphenyl carbonate such as diphenyl carbonate and ditolyl carbonate, dimethyl carbonate, and diethyl carbonate. and di-t-butyl carbonate, among which diphenyl carbonate and substituted diphenyl carbonate are preferred, and diphenyl carbonate is particularly preferred.

Carbonic acid diesters may contain impurities such as chloride ions, and these impurities may inhibit the polymerization reaction or deteriorate the hue of the resulting polycarbonate resin. It is preferable to use one purified by distillation or the like.

The polycarbonate resin used in the present invention is produced by transesterifying a dihydroxy compound containing the dihydroxy compound (1) and the diester carbonate (3) as described above. More specifically, it is obtained by subjecting the compound to transesterification and removing by-products such as monohydroxy compounds out of the system. In this case, the polycondensation is usually carried out by a transesterification reaction in the presence of a transesterification reaction catalyst.

The transesterification catalyst (hereinafter sometimes simply referred to as "catalyst" or "polymerization catalyst") that can be used in the production of the polycarbonate resin used in the present invention is the light transmittance at a wavelength of 350 nm of the obtained polycarbonate resin composition. and can affect the Yellow Index (YI) value.

As the catalyst to be used, among the light resistance, transparency, hue, heat resistance, thermal stability, moldability and mechanical strength of the produced polycarbonate resin composition, if it can satisfy the light resistance in particular. , but not limited to, metal compounds of Group 1 or Group 2 (hereinafter simply referred to as "Group 1" and "Group 2") in the long period periodic table, basic boron compounds, basic phosphorus compounds, basic One or more of basic compounds such as ammonium compounds and amine compounds can be used. Group 1 metal compounds and/or group 2 metal compounds are preferably used.

Basic compounds such as basic boron compounds, basic phosphorus compounds, basic ammonium compounds, and amine compounds can be used together with the Group 1 metal compounds and/or Group 2 metal compounds. However, it is particularly preferred to use only Group 1 metal compounds and/or Group 2 metal compounds.

In addition, as the form of the Group 1 metal compound and/or Group 2 metal compound, it is usually used in the form of a hydroxide or a salt such as a carbonate, a carboxylate, or a phenol salt. Hydroxides, carbonates and acetates are preferred from the viewpoint of ease of handling, and acetates are preferred from the viewpoint of hue and polymerization activity.

Examples of the Group 1 metal compound include sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, cesium hydrogen carbonate, sodium carbonate, potassium carbonate, carbonate Lithium, cesium carbonate, sodium acetate, potassium acetate, lithium acetate, cesium acetate, sodium stearate, potassium stearate, lithium stearate, cesium stearate, sodium borohydride, potassium borohydride, lithium borohydride, hydride Cesium boron, sodium borophenylate, potassium borophenylate, lithium borophenylate, cesium borophenylate, sodium benzoate, potassium benzoate, lithium benzoate, cesium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate , dilithium hydrogen phosphate, dicesium hydrogen phosphate, disodium phenylphosphate, dipotassium phenylphosphate, dilithium phenylphosphate, dicesium phenylphosphate, sodium, potassium, lithium, cesium alcoholates, phenolates , disodium salt, dipotassium salt, dilithium salt and dicesium salt of bisphenol A, among which lithium compounds are preferred.

Examples of the Group 2 metal compounds include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, carbonate Magnesium, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, strontium stearate and the like, among which magnesium compounds, calcium compounds and barium compounds are preferred and have polymerization activity. From the viewpoint of the hue of the resulting polycarbonate resin composition, a magnesium compound and/or a calcium compound are more preferred, and a calcium compound is most preferred.

Examples of the above basic boron compounds include tetramethylboron, tetraethylboron, tetrapropylboron, tetrabutylboron, trimethylethylboron, trimethylbenzylboron, trimethylphenylboron, triethylmethylboron, triethylbenzylboron, triethylphenylboron, Sodium salts, potassium salts, lithium salts, calcium salts, barium salts, magnesium salts, strontium salts of tributylbenzyl boron, tributylphenyl boron, tetraphenyl boron, benzyltriphenyl boron, methyltriphenyl boron, butyltriphenyl boron, etc. is mentioned.

Examples of the above basic phosphorus compounds include triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, tributylphosphine, and quaternary phosphonium salts.

Examples of the above basic ammonium compounds include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide and butyltriphenylammonium hydroxide.

Examples of the above amine compounds include 4-aminopyridine, 2-aminopyridine, N,N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, and 4-methoxypyridine. , 2-dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline and the like.

The amount of the polymerization catalyst used is usually 0.1 μmol to 300 μmol, preferably 0.5 μmol to 100 μmol, per 1 mol of the total dihydroxy compounds used in the polymerization. When a compound containing a metal is used, particularly when a magnesium compound and/or a calcium compound is used, the amount of metal is usually 0.1 μmol or more, preferably 0.5 μmol or more, particularly preferably 0.5 μmol or more, per 1 mol of the total dihydroxy compound. is 0.7 μmol or more. The upper limit is usually 20 µmol, preferably 10 µmol, more preferably 3 µmol, particularly preferably 1.5 µmol, and most preferably 1.0 µmol.

If the amount of the catalyst is too small, the polymerization rate will be slowed down, and as a result, if an attempt is made to obtain a polycarbonate resin with a desired molecular weight, the polymerization temperature must be raised, and the hue and light resistance of the resulting polycarbonate resin will deteriorate. Otherwise, unreacted raw materials may volatilize during polymerization and the molar ratio between the dihydroxy compound (1) of the present invention and the diester carbonate (3) may be disrupted, and the desired molecular weight may not be achieved. On the other hand, if the amount of the polymerization catalyst used is too large, the hue of the resulting polycarbonate resin may deteriorate, and the light resistance of the polycarbonate resin may deteriorate.

Furthermore, when a substituted diphenyl carbonate such as diphenyl carbonate or ditolyl carbonate is used as the carbonate diester (3) to produce the polycarbonate resin used in the present invention, phenol and substituted phenol are by-produced in the polycarbonate resin. It is unavoidable that it remains and is contained in the polycarbonate resin composition, but since the remaining phenol and substituted phenol also have an aromatic ring, they absorb ultraviolet rays and may cause deterioration of light resistance. , may cause odor during molding.

Polycarbonate resin contains 1000 ppm by weight or more of aromatic monohydroxy compound having an aromatic ring such as by-product phenol after normal batch reaction. Using a horizontal reactor with excellent performance or an extruder with a vacuum vent, these are devolatilized and removed, and the content of the aromatic monohydroxy compound in the polycarbonate resin is 700 ppm by weight or less, preferably 500 ppm by weight or less. , particularly preferably 300 ppm by weight or less. However, it is difficult to industrially completely remove the aromatic monohydroxy compound in the polycarbonate resin, and the lower limit of the content of the aromatic monohydroxy compound in the polycarbonate resin is usually 1 ppm by weight.

These aromatic monohydroxy compounds may of course have substituents depending on the raw materials used, and may have, for example, an alkyl group having 5 or less carbon atoms.

In addition, Group 1 metals, especially lithium, sodium, potassium, cesium, especially sodium, potassium, cesium, may adversely affect the hue when contained in a large amount in the polycarbonate resin, while the metal is the catalyst used The total amount of these metals in the polycarbonate resin is usually 1 ppm by weight or less, preferably 0.8 ppm by weight or less, more preferably 0.8 ppm by weight or less, as the amount of metals. should be 0.7 ppm by weight or less.

The amount of metal in the polycarbonate resin can be measured using a method such as atomic emission, atomic absorption, or inductively coupled plasma (ICP) after recovering the metal in the polycarbonate resin by a method such as wet ashing. .

The glass transition temperature (Tg) of the polycarbonate resin is preferably less than 145°C, preferably less than 130°C. If the temperature is higher than 145°C, impregnation of the carbon fiber with the resin is insufficient, and sufficient fluidity cannot be obtained. On the other hand, the lower limit of the glass transition temperature is preferably 80°C or higher, preferably 100°C or higher. If it is lower than 80°C, sufficient mechanical properties cannot be obtained at high temperatures.

The glass transition temperature (Tg) of the matrix resin can be adjusted by appropriately selecting the dihydroxy compound and diester carbonate to be used.

The prepreg of the present invention preferably has a drape value of 1.0 to 5.0 cm. When the drape value is small, the prepreg is rigid and poor in shape followability during preforming, making it difficult to mold into a complicated shape. On the other hand, when the drape value is large, the prepreg lacks elasticity, and the workability of laminating the prepreg is lowered. However, within the above range, both shape followability and workability can be achieved. A more preferred drape value is between 1.2 and 4.8 cm, more preferably between 1.5 and 4.5 cm, and most preferably between 1.8 and 4.0 cm.

The drape value in the present invention is a value obtained by the following method.
First, a prepreg cut into a size of 6 mm in length and 350 mm in width is placed on the upper surface of a horizontal test stand, and a 300 mm portion from the tip of the prepreg in the length direction protrudes into the air. An aluminum plate is placed on the remaining 50 mm portion, and a weight of about 100 g is placed thereon to fix it so that it does not move during measurement. After holding the prepreg so that it is horizontal, the drape value is the distance from the horizontal plane of the test table to the tip of the prepreg in the longitudinal direction 30 seconds after the hold is released and the prepreg is allowed to hang down.

The carbon fiber composite material plate of the present invention is obtained by laminating and integrating the prepregs of the present invention. The carbon fiber composite material plate of the present invention can be produced by a known method. Examples include press molding and autoclave molding.

In the carbon fiber composite material plate of the present invention, the fiber volume content Vf of the fiber composite material plate and the three-point bending strength σ (MPa) measured according to JIS K7074 preferably satisfy the following formula (2). .
400 (MPa) ≤ 42 x σ/Vf ≤ 1200 (MPa) Expression (2)

If the value of the formula (2) is 400 MPa or more, the composite material obtained by molding the prepreg exhibits excellent mechanical properties. In the present invention, although the adverse effects of too high a value of the above formula (2) have not been clarified, it is believed that the effects of the present invention are manifested when the pressure is 1200 MPa or less. Therefore, the value of the above formula (2) is 450 to 1200 MPa, more preferably 500 to 1200 MPa, most preferably 550 to 1200 MPa.

[Example 1]
Carbon fiber fabric (Pyrofil fabric manufactured by Mitsubishi Chemical Corporation, product number: TR6110M, plain weave, fiber basis weight: 288 g/m ² ) is a polycarbonate containing at least a unit structure derived from the dihydroxy compound represented by the above formula (1) of the present invention. The carbon fiber fabric is sandwiched from both sides by films made of resin (Mitsubishi Chemical Co., Ltd. Duravio, product number: D7340R, specific gravity 1.36) with a basis weight of 109 g / m2, and sandwiched between metal flat plates whose surfaces have been subjected to mold release treatment. The carbon fiber fabric was impregnated with a polycarbonate resin containing at least a unit structure derived from the dihydroxy compound represented by the above formula (1) of the present invention under the conditions of 270° C., 7 minutes, and 0.2 MPa using a hot press. While maintaining the press pressure, the mixture was cooled to room temperature to obtain a prepreg having a fiber content of 49% by volume. The drape value of this prepreg was 2.5 cm.

The resulting prepreg was cut into 3 cm squares and embedded in Epomount 27-770 manufactured by Refinetech. After Epomount 27-770 was cured, the cross-section of the specimen was polished to a mirror finish. A cross-sectional photograph of the prepreg was taken using a microscope VHX-5000 manufactured by Keyence Corporation. From the photographed images, the thickness of the gap in the perpendicular direction between the warp carbon fiber bundle and the weft carbon fiber bundle of the carbon fiber fabric that is the reinforcing fiber of the prepreg, and the thickness of the warp carbon fiber bundle and the weft for all the gaps in the prepreg. A ratio of voids existing between the carbon fiber bundles was calculated. The thickness of the gap in the perpendicular direction between the warp carbon fiber bundle and the weft carbon fiber bundle is 30 μm, and the ratio of the gap existing between the warp carbon fiber bundle and the weft carbon fiber bundle to the total gap in the prepreg is 96%. Met.

Also, the obtained prepreg was cut into a size of 120 mm×200 mm, and seven prepregs were laminated in the same direction to produce a prepreg laminate. The prepreg laminate is placed in an inro mold with a size of 120 mm × 200 mm and a depth of 15 mm, and a multi-stage press machine (compression molding machine manufactured by Shindo Kinzoku Kogyo, product name: SFA-50HH0) at 250 ° C. was heated and pressurized at a pressure of 0.1 MPa for 2 minutes. Thereafter, the laminate was cooled to room temperature under the same pressure to obtain a carbon fiber composite material plate having a thickness of 2.2 mm.

A bending test piece having a length of 120 mm and a width of 12.7 mm was cut out from the obtained carbon fiber composite material plate with a wet cutter, and a three-point bending test was performed according to the test method specified in JIS K7074 to measure the bending strength σ. . The bending strength σ was 890 MPa, and the value of 42×σ÷Vf(49) was 690 MPa.

[Comparative Example 1]
Instead of the polycarbonate resin containing at least a unit structure derived from the dihydroxy compound represented by the above formula (1) of the present invention, PMMA resin (Mitsubishi Chemical Co., Ltd. Dianal, product number: RB-2689, specific gravity 1.20). A prepreg is obtained in the same manner as in Example 1, except that it was used. The resulting prepreg has a drape value of 0.9 cm.

When a cross-sectional photograph is taken in the same manner as in Example 1, the thickness of the gap in the perpendicular direction between the warp carbon fiber bundle and the weft carbon fiber bundle is 0 μm, and the warp carbon fiber bundle and the warp carbon fiber bundle with respect to all the gaps in the prepreg. The ratio of voids existing between the carbon fiber bundles of the weft is 0%.

After obtaining a carbon fiber composite material from the obtained prepreg in the same manner as in Example 1, bending strength σ is measured in the same manner as in Example 1. The bending strength σ is 460 MPa, and the value of 42×σ÷Vf (49) is 392 MPa.

Claims (9)

A carbon fiber fabric comprising warp carbon fiber bundles and weft carbon fiber bundles and a thermoplastic resin, wherein the impregnation rate of the thermoplastic resin into the carbon fiber bundles is 85% or more, and the warp carbon fibers A prepreg having a portion where the bundle and the carbon fiber bundle of the weft overlap, and the overlapping portion has voids without the thermoplastic resin. The prepreg according to claim 1, wherein the height of the voids in the direction perpendicular to the plane of the prepreg is 10 to 100 µm. 3. The prepreg according to claim 1 or 2, wherein 80% or more of all voids in the prepreg are present between yarn carbon fiber bundles and weft carbon fiber bundles. The prepreg according to any one of claims 1 to 3, wherein said thermoplastic resin is a polycarbonate resin. The prepreg according to claim 4, wherein the polycarbonate resin includes a unit structure derived from a compound represented by the following formula (1).

... formula (1) The prepreg according to any one of claims 1 to 5, wherein the carbon fiber fabric has a basis weight of 200 to 650 g/ ^m2 . The prepreg according to any one of claims 1 to 6, wherein the prepreg has a drape value of 1 to 5 cm. A carbon fiber composite material plate formed by laminating and integrating the prepreg according to any one of claims 1 to 6. The composite material plate according to claim 8, wherein the fiber volume content Vf of the carbon fiber composite plate and the three-point bending strength σ (MPa) measured according to JIS K7074 satisfy the following formula (2).
400 (MPa) ≤ 42 x σ/Vf ≤ 1200 (MPa)
... formula (2)