JP2023127806A - Prepreg and production method thereof, and molded article - Google Patents

Abstract

To provide a prepreg that does not impair the properties of a fiber-reinforced composite material derived from polyetherimide resin and has improved fluidity at lower temperatures even when polyetherimide resin is used.SOLUTION: There is provided a prepreg including a matrix resin and a carbon fiber base material, wherein the matrix resin contains a polyetherimide resin (A) having a repeating unit represented by the following formula (1) and a crystalline resin (B) having an ether bond, and has a melt viscosity of 6000 Pa s or less at 340°C and a shear rate of 30 s-1. (In the formula (1), n represents 10 to 1000.)SELECTED DRAWING: None

Description

The present invention relates to a prepreg, a method for producing the same, and a molded article.

Engineering plastics, such as crystalline nylon 6 (PA6) resin and amorphous polycarbonate resin (PC), have excellent heat resistance and mechanical strength, and are widely used as industrial parts. In addition, super engineering plastics, such as crystalline polyether-telketone (PEEK) resin and amorphous polyetherimide (PEI) resin, have heat resistance and mechanical strength that exceed engineering plastics. Applications are underway to replace metal parts.

With the aim of further expanding the scope of application of engineering plastics and super engineering plastics, various studies are being conducted on fiber-reinforced composite materials in which matrix resins containing these are reinforced with reinforcing fibers.

Thermoplastic resin prepregs using polyetheretherketone resins or polyetherimide resins alone or in a blend as matrix resins have been proposed because they exhibit particularly excellent properties (see Patent Documents 1 and 2). .

International Publication No. 2019/168009 JP2019-77888A

However, although these resins have excellent properties, they require high temperatures of nearly 400°C during molding, which poses problems in terms of the introduction of molding equipment that can handle high temperatures, safety, and productivity. When attempting to lower the melting point of polyetheretherketone resin in order to lower the molding processing temperature, it is necessary to change the molecular skeleton, and as the melting point lowers, other properties such as glass transition temperature (Tg) may also decrease. be.

One of the objects of the present invention is to create a prepreg with improved fluidity at lower temperatures without impairing the properties of fiber-reinforced composite materials derived from polyetherimide resin, even when polyetherimide resin is used. The goal is to provide the following.

As a result of extensive studies, the present inventors found that by blending a specific resin with polyetherimide resin, the resulting fiber-reinforced composite material retains the properties derived from the polyetherimide resin and has excellent fluidity. It has been found that prepreg can be obtained.

That is, the present invention has the following aspects.

[1] A prepreg comprising a matrix resin and a carbon fiber base material, wherein the matrix resin comprises a polyetherimide resin (A) having a repeating unit represented by the following formula (1) and a crystal having an ether bond. and a matrix resin having a melt viscosity of 6000 Pa·s or less at 340° C. and a shear rate of 30 s ⁻¹ .

（式（１）中、ｎは１０～１０００を表す。）
［２］前記結晶性樹脂（Ｂ）が、ポリエーテルエーテルケトン樹脂（ｂ）を含む、［１］に記載のプリプレグ。
［３］前記ポリエーテルエーテルケトン樹脂（ｂ）の質量平均分子量（Ｍｗ）が４００００以上７５０００以下である、［２］に記載のプリプレグ。
［４］前記マトリックス樹脂が前記ポリエーテルイミド樹脂（Ａ）をマトリックス樹脂１００質量部に対して６０質量部以上含有する、［１］～［３］のいずれかに記載のプリプレグ。
［５］前記マトリックス樹脂が前記結晶性樹脂（Ｂ）をマトリックス樹脂１００質量部に対して３質量部以上含有する、［１］～［４］のいずれかに記載のプリプレグ。
［６］前記マトリックス樹脂が前記ポリエーテルイミド樹脂（Ａ）をマトリックス樹脂１００質量部に対して９５質量部以下含有する、［１］～［５］のいずれかに記載のプリプレグ。
［７］前記マトリックス樹脂が前記結晶性樹脂（Ｂ）をマトリックス樹脂１００質量部に対して４０質量部以下含有する、［１］～［６］のいずれかに記載のプリプレグ。
［８］前記ポリエーテルイミド樹脂（Ａ）の質量平均分子量（Ｍｗ）が３００００以上７００００以下である、［１］～［７］のいずれかに記載のプリプレグ。
［９］前記ポリエーテルイミド樹脂（Ａ）の質量平均分子量（Ｍｗ）より大きい質量平均分子量（Ｍｗ）の結晶性樹脂（Ｂ）が配合されている、［１］～［８］のいずれかに記載のプリプレグ。
［１０］前記ポリエーテルイミド樹脂（Ａ）のガラス転移点より高い結晶融解温度（Ｔｍ）を有する結晶性樹脂（Ｂ）が配合されている、［１］～［９］のいずれかに記載のプリプレグ。
［１１］前記炭素繊維基材が炭素繊維を一方向に引き揃えたシート状基材である、［１］～［１０］のいずれかに記載のプリプレグ。
［１２］前記炭素繊維基材の目付が１０～３００ｇ／ｍ^２である、［１］～［１１］のいずれかに記載のプリプレグ。
［１３］マトリックス樹脂と炭素繊維基材とを含むプリプレグであって、前記マトリクス樹脂が、下記式（１）で表される繰り返し単位を有するポリエーテルイミド樹脂（Ａ）をマトリックス樹脂１００質量部に対して４５質量部以上含有し、動的粘弾性測定（ＤＭＡ：Ｄｙｎａｍｉｃ Ｍｅｃｈａｎｉｃａｌ Ａｎａｌｙｓｉｓ）によって測定される貯蔵弾性率の変曲点（Ｅ‘－Ｔｇ：Ｅ‘－ＯｎｓｅｔでのＴｇ）が２３０℃以下である、プリプレグ。

(In formula (1), n represents 10 to 1000.)
[2] The prepreg according to [1], wherein the crystalline resin (B) contains a polyetheretherketone resin (b).
[3] The prepreg according to [2], wherein the polyetheretherketone resin (b) has a mass average molecular weight (Mw) of 40,000 or more and 75,000 or less.
[4] The prepreg according to any one of [1] to [3], wherein the matrix resin contains 60 parts by mass or more of the polyetherimide resin (A) based on 100 parts by mass of the matrix resin.
[5] The prepreg according to any one of [1] to [4], wherein the matrix resin contains 3 parts by mass or more of the crystalline resin (B) based on 100 parts by mass of the matrix resin.
[6] The prepreg according to any one of [1] to [5], wherein the matrix resin contains 95 parts by mass or less of the polyetherimide resin (A) based on 100 parts by mass of the matrix resin.
[7] The prepreg according to any one of [1] to [6], wherein the matrix resin contains 40 parts by mass or less of the crystalline resin (B) based on 100 parts by mass of the matrix resin.
[8] The prepreg according to any one of [1] to [7], wherein the polyetherimide resin (A) has a weight average molecular weight (Mw) of 30,000 or more and 70,000 or less.
[9] Any one of [1] to [8], wherein a crystalline resin (B) having a mass average molecular weight (Mw) larger than the mass average molecular weight (Mw) of the polyetherimide resin (A) is blended. Prepreg as described.
[10] The resin according to any one of [1] to [9], wherein the crystalline resin (B) having a crystalline melting temperature (Tm) higher than the glass transition point of the polyetherimide resin (A) is blended. prepreg.
[11] The prepreg according to any one of [1] to [10], wherein the carbon fiber base material is a sheet-like base material in which carbon fibers are aligned in one direction.
[12] The prepreg according to any one of [1] to [11], wherein the carbon fiber base material has a basis weight of 10 to 300 g/m ² .
[13] A prepreg containing a matrix resin and a carbon fiber base material, wherein the matrix resin contains a polyetherimide resin (A) having a repeating unit represented by the following formula (1) in 100 parts by mass of the matrix resin. The inflection point of the storage modulus (E'-Tg: Tg at E'-Onset) measured by dynamic mechanical analysis (DMA) is 230°C or less. It is prepreg.

（式（１）中、ｎは１０～１０００を表す。）
［１４］前記Ｅ‘－Ｔｇが１８０℃以上である、［１３］に記載のプリプレグ。
［１５］前記マトリックス樹脂がエーテル結合を有する結晶性樹脂（Ｂ）を含む、［１３］または［１４］に記載のプリプレグ。
［１６］前記結晶性樹脂（Ｂ）が、ポリエーテルエーテルケトン樹脂（ｂ）である、［１５］に記載のプリプレグ。
［１７］前記炭素繊維基材が炭素繊維を一方向に引き揃えたシート状基材である、［１３］～［１６］のいずれかに記載のプリプレグ。
［１８］［１］～［１７］のいずれかに記載のプリプレグを成形してなる成形体。
［１９］下記式（１）で表される繰り返し単位を有するポリエーテルイミド樹脂（Ａ）とエーテル基を有する結晶性樹脂（Ｂ）とを含有するマトリックス樹脂フィルムを、炭素繊維を一方向に引き揃えたシート状基材に積層して、３００～４５０℃に加熱して前記シート状基材にマトリックス樹脂を含浸させることを含み、マトリックス樹脂の３４０℃、せん断速度３０ｓ^－１における溶融粘度が６０００Ｐａ・ｓ以下である、プリプレグの製造方法。

(In formula (1), n represents 10 to 1000.)
[14] The prepreg according to [13], wherein the E'-Tg is 180°C or higher.
[15] The prepreg according to [13] or [14], wherein the matrix resin includes a crystalline resin (B) having an ether bond.
[16] The prepreg according to [15], wherein the crystalline resin (B) is a polyetheretherketone resin (b).
[17] The prepreg according to any one of [13] to [16], wherein the carbon fiber base material is a sheet-like base material in which carbon fibers are aligned in one direction.
[18] A molded article obtained by molding the prepreg according to any one of [1] to [17].
[19] A matrix resin film containing a polyetherimide resin (A) having a repeating unit represented by the following formula (1) and a crystalline resin (B) having an ether group is prepared by pulling carbon fibers in one direction. The method includes laminating the sheet-like base materials that are aligned and impregnating the sheet-like base material with the matrix resin by heating to 300 to 450 °C, and the melt viscosity of the matrix resin at 340 °C and a shear rate of 30 s ^-1 is 6000 Pa.・A prepreg manufacturing method that is less than or equal to s.

（式（１）中、ｎは１０～１０００を表す。）
［２０］前記結晶性樹脂（Ｂ）としてポリエーテルエーテルケトン樹脂（ｂ）を含む、［１９］に記載のプリプレグの製造方法。
［２１］ 前記ポリエーテルイミド樹脂（Ａ）と、前記結晶性樹脂（Ｂ）としてポリエーテルエーテルケトン樹脂（ｂ）とを配合して前記マトリックス樹脂フィルムを得ることを含む、［１９］または［２０］にプリプレグの製造方法。

(In formula (1), n represents 10 to 1000.)
[20] The method for producing a prepreg according to [19], wherein the crystalline resin (B) includes a polyetheretherketone resin (b).
[21] [19] or [20], comprising blending the polyetherimide resin (A) and a polyetheretherketone resin (b) as the crystalline resin (B) to obtain the matrix resin film. ] Method for manufacturing prepreg.

According to the present invention, it is possible to provide a prepreg that has excellent fluidity while retaining the properties derived from polyetherimide resin.

FIG. 1 is a schematic diagram schematically showing an example of a prepreg manufacturing apparatus.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these explanations, and may be implemented with appropriate changes other than the following examples without departing from the spirit of the present invention. . In addition, in this specification, "~" is used to include the numerical values described before and after it as a lower limit value and an upper limit value.

[Prepreg]
An embodiment of the prepreg of the present invention will be described below.
The prepreg of this embodiment includes a matrix resin and a carbon fiber base material. The matrix resin contains a polyetherimide resin (A) having a repeating unit represented by the following formula (1) and a crystalline resin (B) having an ether bond. The melt viscosity at ^-1 is 6000 Pa·s or less. Another form of matrix resin contains 45 parts by mass or more of polyetherimide resin (A) having a repeating unit represented by the following formula (1) based on 100 parts by mass of matrix resin, and dynamic viscoelasticity measurement ( The inflection point of the storage modulus (E'-Tg: Tg at E'-Onset) measured by DMA (Dynamic Mechanical Analysis) is 230°C or less. A prepreg can be obtained by impregnating a carbon fiber base material with a matrix resin.
The prepreg may further contain components (optional components) other than the carbon fiber base material and matrix resin.

（式（１）中、ｎは繰り返し数を表す。）

(In formula (1), n represents the number of repetitions.)

[Carbon fiber base material]
The carbon fiber base material is an aggregate of carbon fibers.
The carbon fibers constituting the carbon fiber base material are not particularly limited, but include, for example, polyacrylonitrile (PAN)-based carbon fibers, petroleum/coal pitch-based carbon fibers, rayon-based carbon fibers, and lignin-based carbon fibers. Among these, PAN-based carbon fibers are preferred.
The carbon fibers may be short carbon fibers of about 0.5 mm to 30 mm, or may be continuous fibers. Continuous fibers are preferred. The fiber length of the continuous fibers can be 50 mm or more.
Base materials using continuous fibers include, for example, sheet forms in which carbon fibers are aligned in one direction, woven forms (for example, plain weave, twill weave, satin weave, etc.), and chopped carbon fiber bundles in which carbon fiber bundles are chopped. Examples include a sheet form in which short carbon fibers are scattered, and a sheet form in which short carbon fibers are scattered.

Carbon fibers are typically used in the form of a carbon fiber bundle in which a plurality of carbon fibers are bundled together.
The number of filaments in the carbon fiber bundle is preferably 1,000 to 60,000, more preferably 1,000 to 50,000, even more preferably 12,000 to 48,000. If the number of filaments in the carbon fiber bundle is within the above range, productivity and mechanical properties on an industrial scale will be excellent. A carbon fiber base material can be obtained by aligning a plurality of continuous carbon fiber bundles, arranging them, forming a sheet, and opening the fibers.

The proportion of the carbon fiber base material in the prepreg, that is, the volume content (Vf) of the carbon fiber base material with respect to the total volume of the prepreg is preferably 40 to 80 volume%, more preferably 40 to 75 volume%, and 45 to 70 volume%. Volume % is more preferred, and 45 to 65 volume % is particularly preferred. If the proportion of the carbon fiber base material is at least the above lower limit, the strength of the molded article (hereinafter also simply referred to as "molded article") formed by molding the prepreg of this embodiment will increase. If the proportion of the carbon fiber base material is below the above upper limit, poor appearance due to insufficient surface resin during molding can be suppressed. The volume content is a value obtained by a measurement method based on ASTM D3171 or JIS K 7075.

The weight of the carbon fiber base material per 1 m ² of prepreg, that is, the basis weight of the carbon fibers is preferably 10 to 300 g/m ² , more preferably 30 to 300 g/m ² . If the basis weight of the carbon fibers is equal to or greater than the above lower limit value, gaps between the carbon fibers due to uneven fiber opening of the carbon fibers will be less likely to occur, and the resin-rich portion of the prepreg will be reduced. If the basis weight of the carbon fiber is below the above upper limit, the impregnating property of the matrix resin into the carbon fiber will be improved, and voids in the prepreg will be reduced.

[Matrix resin]
[Polyetherimide resin (A)]
The matrix resin of this embodiment includes a polyetherimide resin (A) having a repeating unit represented by the following formula (1). If the matrix resin contains the PEI resin (A), the molded article obtained by molding the prepreg of this embodiment will have an excellent balance of heat resistance and mechanical properties.

In the above formula (1), n (repetition number) is usually an integer in the range of 10 to 1000, and is preferably 10 or more, more preferably 20 or more, since it provides an excellent balance between heat resistance and moldability. Further, it is preferably 1000 or less, more preferably 500 or less.

In the repeating unit represented by the above formula (1), the imide bonding position is at the para position. On the other hand, some polyetherimide resins have an imide bonding position at the meta position, such as the repeating unit represented by the following formula (2). The polyetherimide resin (A) used in the present invention preferably has a repeating unit represented by the above formula (1) from the viewpoint of excellent mechanical properties and chemical resistance. , a polyetherimide resin having a repeating unit represented by the following formula (2).

In the above formula (2), n (repetition number) is usually an integer in the range of 10 to 1000, as in formula (1), and is preferably 10 or more, and 20 The above is more preferable. Further, it is preferably 1000 or less, more preferably 500 or less.

The glass transition temperature (Tg) of the polyetherimide resin (A) is preferably 160°C or higher, more preferably 170°C or higher, and particularly preferably 180°C or higher. When the glass transition temperature is 160° C. or higher, the prepreg has sufficient heat resistance. Further, the temperature is preferably 300°C or lower, more preferably 290°C or lower, and particularly preferably 280°C or lower. Since the glass transition temperature is 300° C. or lower, the prepreg can be molded at a relatively low temperature. The glass transition temperature (Tg) of the prepreg indicates the inflection point of the storage modulus (E'-Tg: Tg at E'-Onset) measured by dynamic mechanical analysis (DMA), It can be measured by a method based on ASTM D7028.

The mass average molecular weight (Mw) of the polyetherimide resin (A) is not particularly limited, but from the viewpoint of chemical resistance, it is preferably 20,000 or more, and more preferably 30,000 or more. Further, from the viewpoint of film formability, the molecular weight is preferably 1,000,000 or less, more preferably 700,000 or less.

The molecular weight distribution of the polyetherimide resin (A) is preferably 1.1 or more, more preferably 1.3 or more, and particularly preferably 1.5 or more. Further, the molecular weight distribution is preferably 8.0 or less, more preferably 7.0 or less, and particularly preferably 6.5 or less. If the molecular weight distribution is within the above range, the ratio of high molecular weight components to low molecular weight components is not too high, so mechanical properties and chemical resistance tend to be well balanced.

In addition, in this invention, the said mass average molecular weight (Mw) and molecular weight distribution show the value obtained by measuring by gel permeation chromatography (GPC) under the following conditions.

<GPC measurement conditions>
Equipment used: HLC-8320GPC system manufactured by Tosoh Corporation Column: TSKgel guardcolumn SuperH-H (4.6 mml.D. x 3.5 cm) + TSKgel SuperHM-H (6.0 mml.D. Co., Ltd., product name)
Eluent: PEP (pentafluorophenol) (manufactured by Fuji Film Wako Pure Chemical Industries)/chloroform (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. HPLC grade) = 1/2 (weight ratio)
Column temperature: 40℃
Detector: Differential refractometer (RI detector), polarity=(+)
Calibration curve: cubic approximate curve using standard polystyrene (manufactured by Tosoh) (obtained value is molecular weight in terms of polystyrene)

Commercially available products can be used as the polyetherimide resin (A). Commercially available products include, for example, the "Ultem" series manufactured by Sabic Innovative Plastics.

From the viewpoint of mechanical properties, the content of the polyetherimide resin (A) based on 100 parts by mass of the matrix resin is preferably 45 parts by mass or more, more preferably 60 parts by mass or more, and even more preferably 70 parts by mass or more. On the other hand, from the viewpoint of fluidity, it is preferably 95 parts by mass or less, more preferably 90 parts by mass or less.

[Crystalline resin (B) having ether group]
The crystalline resin (B) having an ether group used in the present invention is not particularly limited as long as it is a crystalline resin having an ether group. The crystalline resin (B) having an ether group can function as a component for improving fluidity and maintaining mechanical properties of the resin composition according to the present embodiment.

Specific examples of the crystalline resin (B) having an ether group include polyoxymethylene resins, polyaryletherketone resins, polyethernitrile resins, and polyimide resins having ether groups. These may be used alone or in combination of two or more. Among these, polyaryletherketone resin is preferred from the viewpoint of compatibility with polyetherimide resin (A). Since the polyaryletherketone resin and the polyetherimide resin (A) have high compatibility and are mixed at the molecular level, it becomes easy to control the glass transition temperature of the prepreg using the polyaryletherketone resin.

Polyaryletherketone resins are homopolymers or copolymers containing monomer units that include one or more aryl groups, one or more ether groups, and one or more ketone groups. For example, polyetheretherketone resin, polyetherketoneketone resin, polyetherketone resin, polyetherketoneetherketoneketone resin, polyetheretherketoneketone resin, polyetherdiphenyl etherketone resin, etc., and copolymers thereof (for example, (polyetherketone-polyether diphenyl ether ketone copolymer). Among these, polyether ether ketone resin (hereinafter referred to as "polyether ether ketone resin (b)") is particularly preferred because it has excellent heat resistance, mechanical properties, chemical resistance, etc.

[Polyetheretherketone resin (b)]
The polyetheretherketone resin (b) may be any resin that has at least two ether groups and a ketone group as structural units, but it has good thermal stability, melt moldability, rigidity, chemical resistance, impact resistance, and durability. Preferably, it has a repeating unit represented by the following formula (3) because it has excellent properties.

(In the above formula (3), Ar ¹ to Ar ³ each independently represent an arylene group having 6 to 24 carbon atoms, which may have a substituent.)

In the above formula (3), the arylene groups Ar ¹ to Ar ³ may be different from each other, but are preferably the same. Specific examples of the arylene groups Ar ¹ to Ar ³ include phenylene groups, biphenylene groups, etc. Among these, phenylene groups are preferred, and p-phenylene groups are more preferred.

Examples of substituents that the arylene group Ar ¹ to Ar ³ may have include alkyl groups having 1 to 20 carbon atoms such as methyl and ethyl groups, and 1 to 20 carbon atoms such as methoxy and ethoxy groups. 20 alkoxy groups and the like. When Ar ¹ to Ar ³ have a substituent, there is no particular restriction on the number of substituents.

Among the polyetheretherketone resins (b), those having a repeating unit represented by the following formula (4) have the best properties in terms of thermal stability, melt moldability, rigidity, chemical resistance, impact resistance, and durability. preferred.

In the above formulas (3) and (4), n (repetition number) is preferably an integer in the range of 10 to 1000, and 10 or more is preferable, and 50 or more is more preferable. Further, it is preferably 1000 or less, more preferably 500 or less. From the viewpoint of impact resistance, it preferably contains 60% by mass or more, and preferably contains 90% by mass or more of a resin having a repeating unit represented by formula (4), based on 100% by mass of polyetheretherketone resin (b). It is more preferable, and it can be 100% by mass. From the viewpoint of impact resistance, it is preferable to contain 60% by mass or more of a resin having a repeating unit represented by formula (4), and 90% by mass based on 100% by mass of the crystalline resin (B) having an ether group. It is more preferable that the content is more than 100% by mass.

The mass average molecular weight (Mw) of the polyetheretherketone resin (b) is preferably 30,000 or more, more preferably 40,000 or more, particularly preferably 45,000 or more. When the mass average molecular weight (Mw) is 30,000 or more, mechanical properties such as durability and impact resistance tend to be excellent. Moreover, the mass average molecular weight (Mw) is preferably 80,000 or less, more preferably 75,000 or less, and particularly preferably 70,000 or less. If the mass average molecular weight (Mw) is 80,000 or less, crystallinity, crystallization rate, and fluidity during melt molding tend to be excellent. A crystalline resin (B) having a mass average molecular weight (Mw) larger than the mass average molecular weight (Mw) of the polyetherimide resin (A) can be blended with the matrix resin.

The molecular weight distribution of the polyetheretherketone resin (b) is preferably 1.2 or more, more preferably 1.4 or more, and particularly preferably 1.5 or more. Further, the molecular weight distribution is preferably 6.0 or less, more preferably 5.0 or less, and particularly preferably 4.5 or less. If the molecular weight distribution is within the above range, the ratio of high molecular weight components to low molecular weight components is not too high, and the prepreg tends to have an excellent balance of crystallinity, fluidity, and mechanical properties.

The mass average molecular weight (Mw) and molecular weight distribution can be determined by gel permeation chromatography (GPC) using an eluent that dissolves the resin component used. For example, as an eluent, a mixture of chlorophenol and halogenated benzenes such as chlorobenzene, chlorotoluene, bromobenzene, bromotoluene, dichlorobenzene, dichlorotoluene, dibromobenzene, dibromotoluene, etc., or a mixture of pentafluorophenol and chloroform It can be measured using the following method using a liquid.
(1) Obtain a polyetheretherketone resin film.
(2) Add 3 g of pentafluorophenol to 9 mg of the film.
(3) Heat and melt at 100°C for 60 minutes using a heat block.
(4) Next, remove from the heat block and allow to cool, then gently add 6 g of chloroform at room temperature (approximately 23°C) little by little and mix gently.
(5) After that, the number average molecular weight (Mn) of the sample obtained by filtration with a 0.45 μm PTFE (polytetrafluoroethylene) cartridge filter was measured using gel permeation chromatography (GPC) under the measurement conditions described above. Measure the mass average molecular weight (Mw) and molecular weight distribution (Mw/Mn).

In addition, a commercially available product can be used as the polyetheretherketone resin (b). Commercially available products include, for example, the "VESTAKEEP" series manufactured by Daicel-Evonik and the "KetaSpire KT" series manufactured by Solvay.

The crystalline melting temperature (Tm) of the crystalline resin (B) having an ether group is preferably 330°C or higher, more preferably 332°C or higher, and particularly preferably 334°C or higher. If the crystal melting temperature (Tm) is 330° C. or higher, the resulting resin composition tends to have excellent heat resistance. On the other hand, the crystal melting temperature (Tm) of the polyetheretherketone resin (b) is preferably 370°C or lower, more preferably 365°C or lower, and particularly preferably 360°C or lower. If the crystal melting temperature (Tm) is 370° C. or lower, fluidity during melt molding will tend to be excellent in the production of composite materials. A crystalline resin (B) having a crystal melting temperature (Tm) higher than the glass transition point of the polyetherimide resin (A) can be blended into the matrix resin.

The crystal melting temperature (Tm) of the crystalline resin (B) having an ether group is measured using a differential scanning calorimeter (for example, PerkinElmer's "Pyris1 DSC") in accordance with JIS K7121:2012 in a temperature range of 25. The temperature can be determined from the peak top temperature of the melting peak of the detected DSC curve by increasing the temperature to ~400°C at a heating rate of 10°C/min.

From the viewpoint of fluidity, the content of the polyetheretherketone resin (b) based on 100 parts by mass of the matrix resin is preferably 3 parts by mass or more, and more preferably 10 parts by mass or more. On the other hand, from the viewpoint of mechanical properties, it is preferably 40 parts by mass or less, more preferably 25 parts by mass or less.

[Content ratio of polyetherimide resin (A) and crystalline resin having ether group (B)]
The matrix resin consists of a polyetherimide resin (A) and a crystalline resin (B) having an ether group such as a polyetheretherketone resin (b). (B) (abbreviated as "(A):(B)") is preferably contained in a content ratio (mass%) of (A):(B) = 60:40 to 99:1.

The content ratio (mass%) of the polyetherimide resin (A) and the crystalline resin (B) having an ether group such as the polyetheretherketone resin (b) is determined from the viewpoint of mechanical properties and chemical resistance. :(B)=60:40 or more is more preferable, still more preferably 70:30 or more, and particularly preferably 80:20 or more. On the other hand, from the viewpoint of fluidity, (A):(B)=99:1 or less is more preferable, still more preferably 97:3 or less, and particularly preferably 95:5 or less.

The weight content of the matrix resin in the prepreg is preferably 15 to 70% by weight, more preferably 20 to 60% by weight, even more preferably 25 to 45% by weight. If the weight content of the matrix resin is equal to or greater than the above lower limit, sufficient adhesion between the carbon fibers and the matrix resin can be ensured. If the weight content of the matrix resin is below the above upper limit, the reinforcing effect of the carbon fibers will be sufficiently exhibited, and the bending strength of the molded article will be further increased. The weight content is a value obtained by a measuring method based on ASTM D3171 or JIS K 7075.

[Optional ingredients]
The prepreg may contain reinforcing fibers other than carbon fibers (hereinafter also referred to as "other fibers"). As other fibers, inorganic fibers other than carbon fibers, organic fibers, metal fibers, or reinforcing fibers with a hybrid structure combining these can be used. Examples of inorganic fibers other than carbon fibers include graphite fibers, silicon carbide fibers, alumina fibers, tungsten carbide fibers, boron fibers, and glass fibers. Examples of organic fibers include aramid fibers, high-density polyethylene fibers, other general nylon fibers, and polyester fibers. Examples of the metal fiber include fibers of stainless steel, iron, and the like. Examples of reinforcing fibers with a hybrid structure include metal-coated carbon fibers. Among these, glass fiber is preferable as the other fiber, considering the mechanical properties such as the strength of the prepreg.
One type of other fibers may be used alone, or two or more types may be used in combination.

The prepreg may further contain additives other than reinforcing fibers.
Examples of additives include flame retardants, weatherability improvers, antioxidants, heat stabilizers, ultraviolet absorbers, plasticizers, lubricants, colorants, compatibilizers, conductive fillers, and the like.
One type of additive may be used alone, or two or more types may be used in combination.

[Physical properties of matrix resin set]
The glass transition temperature (Tg) of the matrix resin is preferably lower than the Tg of the resin alone having the repeating unit represented by the above formula (1), preferably 230°C or lower, and 215°C or lower. More preferably, the temperature is 210°C or lower. Since the glass transition temperature is 222° C. or lower, molding or secondary processing can be performed at relatively low temperatures without adversely affecting physical properties. On the other hand, the glass transition temperature (Tg) of the matrix resin is preferably 160°C or higher, more preferably 170°C or higher, and particularly preferably 180°C or higher. When the glass transition temperature is 160° C. or higher, the obtained molded product has sufficient heat resistance.

The glass transition temperature (Tg) of the matrix resin was measured according to ASTM D7028 using a dynamic viscoelasticity measurement device (DMA Q800, manufactured by TA Instruments) at a heating rate of 5°/min from room temperature to 250°C. The inflection point of the storage modulus E' at a frequency of 1 Hz and a strain of 0.01% was defined as Tg (E'-Tg).

Note that if the loss tangent (tan δ) curve measured under the above conditions has a single peak, the glass transition temperature is single and there is no phase separation; if the tan δ curve has multiple peaks, there are multiple glass transition temperatures. It can be said that there is phase separation. The single peak may have a shoulder at its base, and the peak derived from the crystalline resin (B) having an ether group such as polyetherimide resin (A) and polyetheretherketone resin (b) Unless two or more are clearly observed, all systems are treated as compatible systems.

In addition, the difference between the glass transition temperature Tg (a) of the polyetherimide resin (A) and the glass transition temperature Tg (b) of the matrix resin [Tg (a) - Tg (b)] is the fluidity From this viewpoint, the temperature is preferably 3.0°C or higher, more preferably 5.0°C or higher, and particularly preferably 7.0°C or higher. On the other hand, [Tg(a)-Tg(b)] is preferably 50°C or less, more preferably 40°C or less, and particularly preferably 35°C or less from the viewpoint of heat resistance.

The melt viscosity of the matrix resin at 340° C. and a shear rate of 10 s ⁻¹ is preferably 500 Pa·s or more, and 1000 Pa.・s or more is more preferable, and 1500 Pa·s or more is particularly preferable. On the other hand, the melt viscosity at 340°C and a shear rate of 10 s ^-1 is preferably 6000 Pa·s or less, more preferably 5000 Pa·s or less, and 4000 Pa·s or less, since the matrix resin easily impregnates the carbon fiber base material. Particularly preferred. If the melt viscosity at 340° C. and a shear rate of 10 s ⁻¹ is within the above range, the melt viscosity will be in an appropriate range, and the fluidity and moldability will tend to be excellent.

In addition, the melt viscosity of the matrix resin is measured at 340°C or 380°C at a shear rate of 0.1 to 380°C using a capillary rheometer (for example, "Capillograph 1D" manufactured by Toyo Seiki Seisakusho Co., Ltd.) according to JIS K7199:1999. It can be calculated by measuring under the condition of 10,000 s ⁻¹ .

[Prepreg manufacturing method]
The prepreg manufacturing method is not particularly limited, and can be manufactured by any known method. For example, prepreg can be manufactured by impregnating a carbon fiber base material with the matrix resin described above.
As a method for impregnating the matrix resin, for example, the matrix resin is processed into a film with a thickness of about 10 to 100 μm, fibers with a fiber diameter of about 5 to 50 μm, or powder with an average particle size of about 10 to 100 μm, and then carbon fibers are formed. Examples include a method of attaching it to a base material.

When the prepreg contains an additive, a matrix resin composition may be prepared by mixing the matrix resin and the additive, and the carbon fiber base material may be impregnated with this matrix resin composition.
When the prepreg contains other fibers, a reinforcing fiber base material containing carbon fibers and other fibers may be impregnated with the matrix resin composition.

An embodiment of a prepreg manufacturing method will be described below.
In the prepreg manufacturing method of the present embodiment, a resin film made of the above-mentioned matrix resin is laminated on a carbon fiber base material and heated and pressurized to impregnate the carbon fiber base material with the resin contained in the resin film, thereby producing a prepreg. Manufacture. Specifically, using the manufacturing apparatus 10 shown in FIG. 1, the carbon fiber base material 11 is unwound from the roll 18. Separately, the resin film 12 is unwound from a plurality of rolls 18 and via the pressure roller 19, the resin film 12 is laminated on the upper and lower surfaces of the carbon fiber base material 11 to form a laminate, and is preheated by the heater 13. After performing this, release films 14 are placed on the upper and lower surfaces of the laminate. Next, the matrix resin in the laminate is carbonized by pressurizing with a hot plate press 15 heated above the melting point (or flow start temperature) in the range of 300 to 450°C, and pressurizing with a cooling press 16 cooled below the solidification temperature. The fiber base material 11 is impregnated. Thereafter, the release film 14 is removed to obtain the prepreg 17.

When manufacturing the prepreg 17 using the manufacturing apparatus 10 shown in FIG. 1, the resin films 12 laminated on the upper and lower surfaces of the carbon fiber base material 11 may be of the same type or may be of different types.

Further, in the manufacturing apparatus 10 shown in FIG. 1, the resin film 12 is laminated on the upper and lower surfaces of the carbon fiber base material 11, but the carbon fiber base material 11 and the resin film 12 may be replaced. That is, the carbon fiber base material 11 is laminated on the upper and lower surfaces of the resin film 12 to form a laminate, and the matrix resin in the laminate is impregnated into the carbon fiber base material 11 by heating and pressurizing, thereby producing a prepreg. Good too.

Forms of prepreg obtained in this way include unidirectional prepreg (UD prepreg), which is a sheet-like carbon fiber base material made of carbon fibers aligned in one direction and impregnated with matrix resin, and carbon fiber woven fabric with matrix resin. Examples include impregnated cloth prepreg, tow preg in which tow (carbon fiber bundle) is pre-impregnated with matrix resin, and random prepreg in which randomly dispersed carbon fibers are impregnated with matrix resin. The prepreg may have notches in order to make it easier to fit along the mold.
The thickness of one sheet of prepreg can be 0.04 to 0.7 mm or 0.04 to 0.4 mm.

[Molded object]
The molded body is formed by molding the prepreg described above.
The molded body is a laminate in which one or more prepregs of the above-described embodiments are laminated. Note that the molded body may be a molded body obtained by molding a laminate obtained by laminating a combination of the prepreg of the above-described embodiment and another prepreg other than the above-described embodiment.

The laminated structure of prepregs in the laminate is not particularly limited.
The number of layers of prepreg in the laminate can be appropriately set depending on the thickness of the prepreg and the thickness required for the molded product.
When the prepreg is a UD prepreg, the fiber direction of the carbon fibers of each UD prepreg to be laminated can be appropriately set depending on the physical properties required of the molded article. The carbon fibers of each UD prepreg may have the same fiber direction. For example, if isotropy is required for the physical properties of the molded object, the fiber direction of the carbon fibers in plan view of each UD prepreg to be laminated may be set to a combination of 0° and 90°, 0°, 45°, 90°, etc. It is preferable to use a combination of angles of 0°, -45°, or 0°, 60°, and -60°, and to stack them symmetrically in the thickness direction.

[Method for manufacturing molded body]
The molded body is obtained by molding prepreg.
The prepreg molding method is not particularly limited, but methods include molding one prepreg or a stack of multiple prepregs according to the above embodiments using a mold press method, an autoclave method, a hot/cold press method, etc. Can be mentioned. The prepreg of the above-mentioned form can be molded into a molded body by using a mold press method at a set temperature of 340° C. and a set pressure of 2.5 MPa or 5 MPa, for example. In the mold pressing method, the molding temperature can be 300°C to 400°C or 300°C to 350°C, and the pressure can be 1 to 10 MPa or 2 to 6 MPa.
Examples of methods for laminating prepreg include automatic lamination using a robot.

EXAMPLES The present invention will be specifically explained below using Examples, but the present invention is not limited thereto.

[Evaluation method]
The melt viscosity of the obtained matrix resin was determined using a capillary rheometer (manufactured by Toyo Seiki Seisakusho Co., Ltd., Capillograph 1D) at 340°C and 360°C and a shear rate of 0.1 to 10000 s ^-1 in accordance with JIS K7199:1999. Melt viscosity was measured.

(2) Internal Defect Area The internal defects of the obtained molded plate were evaluated using an ultrasonic flaw detection imaging device (manufactured by KJTD, SDS-6500 MR). Adjust the wavelength so that the ultrasonic transmittance in the center of the molded plate, where it is assumed that there are few internal defects, is 80% or more, irradiate the entire molded plate with ultrasonic waves, and calculate the internal defect area using the following formula. did. "Internal defect area = ((area with transmittance less than 80%) / (formed plate area)) x 100"

(3) Glass transition temperature (Tg)
A test piece was obtained from the obtained molded plate and heated at a heating rate of 5°/min from room temperature to 250°C using a dynamic viscoelasticity measuring device (DMA Q800, manufactured by TA Instruments) according to ASTM D7028. , Tg (E'-Tg: inflection point of storage modulus (E)) was measured at a frequency of 1 Hz and a strain of 0.01%. Further, the dimensions of the test piece used in the measurement were 12.7 mm in width and 55 mm in length.

(4) 90° bending A test piece was obtained from the obtained molded plate, and a universal testing machine was installed with a three-point bending jig (indenter R = 5.0 mm, support R = 3.2 mm) according to ASTM D790. (manufactured by INSTRON, INSTRON 5565), the ratio of the distance between supports (L) to the thickness (d) of the specimen L/d = 16, and the crosshead speed = (L ² × 0.01) / (6 A 90° bending test was conducted under the conditions of ×d), and the 90° bending strength was measured. Further, the dimensions of the test piece used in the measurement were 12.7 mm in width and 50 mm in length.

[Polyetherimide resin (A)]
PEI: Polyetherimide (manufactured by SABIC Innovative Plastics, Ultem CRS5001, glass transition temperature Tg (a): 228 ° C., mass average molecular weight (Mw): 48000, molecular weight distribution (Mw / Mn): 2.91, heat of crystal fusion (ΔHm): 0.0J/g, has a repeating unit of formula (1).)

[Polyetheretherketone resin (b) (both have repeating units of formula (4))]
PEEK-1: Polyetheretherketone (manufactured by Daicel Evonik, VESTAKEEP2000G, mass average molecular weight: 60000, molecular weight distribution (Mw/Mn): 4.00, heat of crystal fusion (ΔHm): 48.0, crystallization temperature ( Tc): 302℃)
PEEK-2: Polyether ether ketone (manufactured by Solvay, KetaSpire KT-880NT, mass average molecular weight: 58000, molecular weight distribution (Mw/Mn): 3.22, heat of crystal fusion (ΔHm): 42.1, crystallization temperature ( Tc): 298°C)

[Example 1]
After dry blending polyetherimide resin (PEI) and polyether ether ketone resin (PEEK-1) at a mixing mass ratio of 80:20, the mixture was kneaded at 360°C using a φ40 mm co-directional twin-screw extruder. It was extruded through a T-die and then rapidly cooled with a casting roll at about 200°C to produce a film with a thickness of 23 μm. The obtained film was evaluated for melt viscosity. The evaluation results are shown in Table 1.

The previously prepared film was laminated on both sides of the carbon fiber sheet on a carbon fiber sheet made of PAN-based carbon fibers (manufactured by Mitsubishi Chemical Corporation, MR50R, 570tex, 12,000 strands) oriented in one direction, and the film/carbon A prepreg was produced by heat-melting and impregnating a carbon fiber sheet with a film having a fiber sheet/film configuration. The thickness of the obtained prepreg was 0.18 mm, and the volume content (Vf) of carbon fiber measured according to ASTM D3171 was 60% by volume.

Eleven pieces of prepreg cut into dimensions of 118 mm x 198 mm were laminated so that the fiber directions were all oriented in the 0° direction to produce two laminates each having a thickness of 2 mm.
One of the obtained laminates was placed in the lower mold of a steel mold, and after closing the upper mold, it was heated to 340°C in a two-stage heating and cooling press (manufactured by Shinto Metal Industry Co., Ltd., 50 ton press). After preheating the mold to 340° C. in about 10 minutes in a heating platen set at 2.5 MPa, compression molding was performed for 15 minutes under a molding condition of 2.5 MPa. Thereafter, the mold was transferred to a cooling plate whose temperature was adjusted to 80° C., and the temperature was lowered to 150° C. in about 2 minutes to obtain a molded product of 120 mm×200 mm (thickness: 2 mm). Another laminate was compression-molded in the same manner except that the heating platen temperature was set at 360° C. to obtain a 120 mm x 200 mm molded body (2 mm thick).
The obtained molded body was evaluated for internal defect area, Tg, and 90° bending. The results are shown in Table 1.

[Example 2]
A film and a molded article were obtained in the same manner as in Example 1 except that PEEK-2 was used instead of PEEK-1. Table 1 shows the evaluation results of the obtained films and molded bodies.

[Comparative example 1]
A film and a molded article were obtained in the same manner as in Example 1 except that polyetherimide resin (PEI) was used alone. Table 1 shows the evaluation results of the obtained films and molded bodies.

[Comparative example 2]
A film and a molded article were obtained in the same manner as in Example 1 except that PEEK-2 was used alone. Table 1 shows the evaluation results of the obtained films and molded bodies. Note that melt viscosity measurement at 340°C and compression molding at a mold temperature of 340°C were not performed.

As is clear from Table 1, Examples 1 and 2 had fewer internal defect areas and higher 90° bending strength at any molding temperature, compared to Comparative Example 1 in which polyetherimide resin was used alone. Ta. One reason for this is that the lower melt viscosity of the matrix resin improves resin fluidity at the same molding temperature, which reduces internal defects such as internal voids and resin-rich areas that occur during compression molding. Conceivable. On the other hand, the Tg of Examples 1 and 2 was about 5% lower than that of Comparative Example 1. In Examples 1 and 2, the heat resistance derived from polyetherimide is maintained while improving moldability.
Example 1 exhibits the same 90° bending strength as Comparative Example 2 in which polyetheretherketone was used alone, while also achieving heat resistance. The melt viscosity of Comparative Example 2 at 340° C. is above the measurement limit and greatly exceeds 6000 Pa·s, and it is thought that compression molding of Comparative Example 2 at 340° C. does not flow sufficiently, so a molded article cannot be produced.

The prepreg and molded body of the present invention can be used for structural parts such as sports equipment, automobiles, pressure tanks, aircraft, tendons, etc.

10 Manufacturing equipment 11 Carbon fiber base material 12 Resin film 13 Heater 14 Release film 15 Hot plate press 16 Cooling press 17 Prepreg 18 Roll 19 Pressure roller

Claims (21)

A prepreg comprising a matrix resin and a carbon fiber base material, the matrix resin comprising a polyetherimide resin (A) having a repeating unit represented by the following formula (1) and a crystalline resin having an ether bond ( B), wherein the matrix resin has a melt viscosity of 6000 Pa·s or less at 340° C. and a shear rate of 30 s ⁻¹ .

(In formula (1), n represents 10 to 1000.) The prepreg according to claim 1, wherein the crystalline resin (B) includes a polyetheretherketone resin (b). The prepreg according to claim 2, wherein the polyetheretherketone resin (b) has a mass average molecular weight (Mw) of 40,000 or more and 75,000 or less. The prepreg according to any one of claims 1 to 3, wherein the matrix resin contains the polyetherimide resin (A) at 60 parts by mass or more based on 100 parts by mass of the matrix resin. The prepreg according to any one of claims 1 to 4, wherein the matrix resin contains 3 parts by mass or more of the crystalline resin (B) based on 100 parts by mass of the matrix resin. The prepreg according to any one of claims 1 to 5, wherein the matrix resin contains 95 parts by mass or less of the polyetherimide resin (A) based on 100 parts by mass of the matrix resin. The prepreg according to any one of claims 1 to 6, wherein the matrix resin contains 40 parts by mass or less of the crystalline resin (B) based on 100 parts by mass of the matrix resin. The prepreg according to any one of claims 1 to 7, wherein the polyetherimide resin (A) has a weight average molecular weight (Mw) of 30,000 or more and 70,000 or less. The prepreg according to any one of claims 1 to 8, wherein a crystalline resin (B) having a mass average molecular weight (Mw) larger than the mass average molecular weight (Mw) of the polyetherimide resin (A) is blended. . The prepreg according to any one of claims 1 to 9, wherein a crystalline resin (B) having a crystalline melting temperature (Tm) higher than the glass transition point of the polyetherimide resin (A) is blended. The prepreg according to any one of claims 1 to 10, wherein the carbon fiber base material is a sheet-like base material in which carbon fibers are aligned in one direction. The prepreg according to any one of claims 1 to 11, wherein the carbon fiber base material has a basis weight of 10 to 300 g/m ² . A prepreg containing a matrix resin and a carbon fiber base material, wherein the matrix resin contains 45 parts by mass of a polyetherimide resin (A) having a repeating unit represented by the following formula (1) based on 100 parts by mass of the matrix resin. The inflection point of the storage modulus (E'-Tg: Tg at E'-Onset) measured by dynamic mechanical analysis (DMA) is 230°C or less, prepreg.

(In formula (1), n represents 10 to 1000.) The prepreg according to claim 13, wherein the E'-Tg is 180°C or higher. The prepreg according to claim 13 or 14, wherein the matrix resin includes a crystalline resin (B) having an ether bond. The prepreg according to claim 15, wherein the crystalline resin (B) is a polyetheretherketone resin (b). The prepreg according to any one of claims 13 to 16, wherein the carbon fiber base material is a sheet-like base material in which carbon fibers are aligned in one direction. A molded article obtained by molding the prepreg according to any one of claims 1 to 17. A sheet in which carbon fibers are aligned in one direction and a matrix resin film containing a polyetherimide resin (A) having a repeating unit represented by the following formula (1) and a crystalline resin (B) having an ether group. laminating it on a sheet-like base material and impregnating the sheet-like base material with a matrix resin by heating it to 300 to 450 °C, and the melt viscosity of the matrix resin at 340 °C and a shear rate of 30 s ^-1 is 6000 Pa · s or less A method for manufacturing prepreg.

(In formula (1), n represents 10 to 1000.) The method for producing a prepreg according to claim 19, wherein the crystalline resin (B) includes a polyetheretherketone resin (b). Prepreg production according to claim 19 or 20, comprising blending the polyetherimide resin (A) and a polyetheretherketone resin (b) as the crystalline resin (B) to obtain the matrix resin film. Method.

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