JP6922154B2 - Fiber reinforced thermoplastic resin composite material and molded product - Google Patents

Description

The present invention relates to a fiber-reinforced thermoplastic resin composite material and a molded product that are suitably used for aircraft members, spacecraft members, automobile members, ship members, electronic device members, sports-related members, and the like.

Carbon fiber, glass fiber, and aramid fiber have a lower specific gravity than metal, but have excellent elastic modulus and strength. Therefore, composite materials combined with various matrix resins are used for aircraft members, spacecraft members, automobile members, and so on. It is used in many fields such as ship materials, civil engineering and building materials, and sporting goods. In particular, composite materials that combine carbon fiber with epoxy resin or unsaturated polyester resin are widely used.

Conventional thermosetting carbon fiber reinforced composite materials have a drawback that it takes a long time to heat cure, but in recent years, carbon fiber reinforced composite materials using a thermoplastic resin as a matrix (hereinafter sometimes referred to as "CFRTP"). Is expected and developed as a composite material capable of high cycle molding.
Short fiber reinforced thermoplastic composite materials capable of forming complex shapes have already been put into practical use, but there is a problem that the elastic modulus is significantly lower than that of light metals because the fiber length of the reinforced fibers is short. Therefore, a thermoplastic resin composition reinforced with continuous fibers is strongly desired.

Inexpensive general-purpose plastics such as polypropylene (PP) and acrylonitrile butadiene rubber styrene (ABS) are expected as the matrix resin used for this CFRTP, but the mechanical properties of the composite material of these thermoplastic resins and carbon fibers in particular, particularly bending. The strength was not sufficient.

Proposal to improve the interfacial adhesion between carbon fiber and matrix resin by subjecting carbon fiber to oxidation treatment such as vapor phase oxidation or liquid phase oxidation for the purpose of improving bending strength and introducing oxygen-containing functional groups on the surface of the carbon fiber. Is being done.
For example, Patent Document 1 proposes a method of improving the interlayer shear strength, which is an index of interfacial adhesiveness, by subjecting carbon fibers to electrolytic treatment. The bending strength was not sufficient.

Further, the problem of the carbon fiber itself is that it is brittle and has poor focusing property and abrasion resistance, and fluff and thread breakage are likely to occur in the higher processing process.
For the purpose of improving this problem, a method of applying a sizing agent to carbon fibers has been proposed as described in Patent Documents 2 and 3, but the sizing agent sufficiently imparts the adhesiveness of the carbon fibers to the thermosetting resin. However, the interfacial adhesion with the thermoplastic resin was still low, and the bending strength of the thermoplastic resin composite material reinforced with the sizing-treated reinforcing fibers was not sufficient.

As described above, in order to improve the bending strength, the treatment on the carbon fiber side alone is not sufficient, and a thermoplastic carbon fiber composite material having sufficient bending strength cannot be achieved by the existing technology.

Japanese Unexamined Patent Publication No. 04-361619 U.S. Pat. No. 3,957,716 Tokukousho 62-056266 Gazette

An object of the present invention is to provide a fiber-reinforced thermoplastic resin composite material having excellent interfacial adhesiveness between a reinforcing fiber and a thermoplastic resin and excellent bending strength and flexural modulus in view of the above-mentioned problems in the prior art. Is.

The present inventor has found that in a fiber-reinforced thermoplastic resin composite material containing a continuous reinforcing fiber and a thermoplastic resin, the above-mentioned object can be achieved by including the polycarbonate resin having a specific structure in the thermoplastic resin. rice field.
That is, the present invention is as shown below.

（式［１］中、Ｒは単結合、炭素原子数１〜６のアルキレン基、炭素原子数６〜１０のア
リーレン基、または炭素原子数３〜８の環状アルキレン基を表し、Ｘ及びＹはそれぞれ独
立に炭素原子数１〜６のアルキル基を表す。） [1] A fiber-reinforced thermoplastic tree composite material containing a continuous reinforcing fiber (A) and a thermoplastic resin (B), wherein the thermoplastic resin (B) is a structural unit represented by the following formula [1]. A fiber-reinforced thermoplastic resin composite material, which comprises a polycarbonate (C) containing.

(In the formula [1], R represents a single bond, an alkylene group having 1 to 6 carbon atoms, an arylene group having 6 to 10 carbon atoms, or a cyclic alkylene group having 3 to 8 carbon atoms, and X and Y are. Each independently represents an alkyl group having 1 to 6 carbon atoms.)

[2] The fiber-reinforced thermoplastic resin composite material according to [1], which contains 1 to 80% by mass of the continuous reinforcing fiber (A) and 20 to 99% by mass of the thermoplastic resin (B).

[3] The fiber-reinforced thermoplastic resin composite material according to [1] or [2], wherein the average fiber length of the continuous reinforcing fibers (A) is 10 mm or more.

[4] The method according to any one of [1] to [3], wherein the continuous reinforcing fiber (A) contains at least one selected from the group consisting of carbon fiber, glass fiber and aramid fiber. Fiber reinforced thermoplastic resin composite material.

[5] The fiber-reinforced thermoplastic resin composite material according to any one of [1] to [4], wherein the content ratio of the polycarbonate (C) in the thermoplastic resin (B) is 50 to 100% by mass.

[6] The polycarbonate (C) is a polycarbonate copolymer containing 20 to 100% by mass of a structural unit represented by the following formula [2] and 80 to 0% by mass of a structural unit represented by the following formula [3]. Alternatively, the fiber-reinforced thermoplastic resin composite material according to any one of [1] to [6], which is a copolymer.

[7] A molded product using the fiber-reinforced thermoplastic resin composite material according to any one of [1] to [6].

[8] The molded product according to [7], wherein another transparent resin is laminated on the surface of the fiber-reinforced thermoplastic resin composite material.

[9] The molded product according to [7] or [8], which has a maximum bending strength of 300 MPa or more.

A fiber-reinforced thermoplastic resin composite material having excellent mechanical strength can be obtained by using polycarbonate having a specific structure and continuously reinforcing fibers.

The fiber-reinforced thermoplastic resin composite material of the present invention is a fiber-reinforced thermoplastic resin composite material containing continuous reinforcing fibers and a thermoplastic resin, and the thermoplastic resin is characterized by containing a polycarbonate resin having a specific structure. And.

<Continuous reinforcement fiber (A)>
The continuous reinforcing fiber (A) used in the present invention is a glass fiber, a carbon fiber or an aramid fiber, and the carbon fiber is preferable from the viewpoint of elastic modulus.
The fiber length of the continuous reinforcing fiber (A) is preferably 10 mm or more on average.
Further, examples of the form of the continuous reinforcing fiber include a unidirectional sheet, a woven sheet, a multi-axis laminated sheet and the like, and specific examples thereof are shown below, but the present invention is not limited.

Glass fiber: (manufactured by Nitto Boseki Co., Ltd.) WF 350 100 BS6
Aramid fiber: (Made by Teijin Limited) Twaron Carbon fiber: (Made by Arisawa Mfg. Co., Ltd.) CFP3113

The ratio of the continuously reinforced fiber (A) in the fiber-reinforced thermoplastic resin composite material of the present invention is 1 to 80% by mass, and is preferably 50 to 75% by mass from the viewpoint of the mechanical properties of the fiber-reinforced thermoplastic resin composite material. %.

式［１］中、Ｒは単結合、炭素原子数１〜６のアルキレン基、炭素原子数６〜１０のアリーレン基、または炭素原子数３〜８の環状アルキレン基を表し、Ｘ及びＹはそれぞれ独立に炭素原子数１〜６のアルキル基を表す。好ましいＲは、イソプロピリデン基であり、好ましいＸ及びＹは、メチル基、エチル基、n−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、sec−ブチル基、tert-ブチル基、ｎ−ペンチル基、ｓｅｃ−ペンチル基、ｎ−ヘキシル基であり、特に好ましくは、メチル基、エチル基、ｓｅｃ−ブチル基である。 <Thermoplastic resin (B)>
The polycarbonate (C) contained in the thermoplastic resin (B) used in the present invention is a polycarbonate containing a structural unit represented by the following formula [1], and is a polycarbonate containing a structural unit represented by the formula [1]. If so, either a monopolymer or a copolymer can be used.

In the formula [1], R represents a single bond, an alkylene group having 1 to 6 carbon atoms, an arylene group having 6 to 10 carbon atoms, or a cyclic alkylene group having 3 to 8 carbon atoms, and X and Y represent, respectively. It independently represents an alkyl group having 1 to 6 carbon atoms. Preferred R is an isopropylidene group, and preferred X and Y are methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-. It is a pentyl group, a sec-pentyl group, or an n-hexyl group, and a methyl group, an ethyl group, or a sec-butyl group is particularly preferable.

In the present invention, the polycarbonate (C) preferably contains 20 to 100% by mass, more preferably 40 to 100% by mass, and 60 to 100% by mass of the structural unit represented by the above formula [1]. Is particularly preferable. When the polycarbonate (C) is a copolymer, a structural unit other than the structural unit represented by the above formula [1] may be contained as long as the effect of the present invention is not impaired.

で表される構成単位２０〜１００質量％と、下記式［３］

で表される構成単位８０〜０質量％を含むポリカーボネート単一重合体もしくは共重合体
であることが好ましい。更に、上記式［２］で表される構成単位が４０〜１００質量％で
あることがより好ましく、上記式［２］で表される構成単位が６０〜１００質量％である
ことが特に好ましい。 Further, in the present invention, the polycarbonate (C) is represented by the following formula [2].

20 to 100% by mass of the structural unit represented by, and the following formula [3]

It is preferably a polycarbonate monopolymer or copolymer containing 80 to 0% by mass of the structural unit represented by. Further, the structural unit represented by the above formula [2] is more preferably 40 to 100% by mass, and the structural unit represented by the above formula [2] is particularly preferably 60 to 100% by mass.

Specific examples of the monomer constituting the polycarbonate (C) that is particularly preferably used in the present invention include 2,2-bis (4-hydroxy-3-methylphenyl) propane and 2,2-bis (4-hydroxy-3-3). Ethylphenyl) propane, 2,2-bis (4-hydroxy-3-sec-butylphenyl) propane, 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane and the like can be mentioned, but are limited thereto. It's not something.

The proportion of the polycarbonate (C) in the thermoplastic resin (B) used in the present invention is preferably 50 to 1000% by mass, more preferably 80 to 100% by mass, and particularly preferably 100% by mass. The fiber-reinforced thermoplastic resin composite material obtained by such a ratio has mechanical strength.
The thermoplastic resin (B) may contain components other than the polycarbonate (C) as long as the effects of the invention are exhibited, and other resins and various additives such as mold release agents, flame retardants, and antioxidants. Can be blended.
For example, engineering plastics and super engineering plastics (polyamide, polyester, etc.) for the purpose of improving heat resistance and chemical resistance can be added and used as an alloy.
The ratio of these components in 100% by mass of the thermoplastic resin (B) is 0 to 50% by mass, and those having 0 to 20% by mass are preferable because an inexpensive fiber-reinforced thermoplastic resin composite material can be obtained.

<Fiber-reinforced thermoplastic resin composite material>
The ratio of the continuous reinforcing fiber (A) to the thermoplastic resin (B) in the fiber-reinforced thermoplastic resin composite material of the present invention is usually 1 to 80% by mass of the continuous reinforcing fiber (A), and the thermoplastic resin (B) 20. It is ~ 99% by mass, and is preferably 50 to 75% by mass of the continuous reinforcing fiber (A) and 25 to 50% by mass of the thermoplastic resin (B) from the viewpoint of the mechanical properties of the fiber-reinforced thermoplastic resin composite material. ..
If the proportion of reinforcing fibers is less than this range, the mechanical properties of the fiber-reinforced thermoplastic resin composition will be equal to or less than that of light metals, and if the proportion of reinforcing fibers is more than this range, the amount of resin will be small. The focusing action of the reinforcing fibers by the matrix resin does not work, and the mechanical strength is reduced.
The total ratio of the continuously reinforced fibers (A) and the thermoplastic resin (B) in the fiber-reinforced thermoplastic resin composite material of the present invention is usually 70% by mass or more, preferably 80% by mass or more, more preferably 90. It is 100% by mass or more, particularly preferably 100% by mass.
The fiber-reinforced thermoplastic resin composite material of the present invention may contain components other than the continuous reinforcing fiber (A) and the thermoplastic resin (B). Examples of these components include various additives such as mold release agents, flame retardants, and antioxidants.

The method for producing the fiber-reinforced thermoplastic resin composite material is not particularly limited. For example, the molten resin of the thermoplastic resin (B) is poured from the T-die of the extruder and merged with the fed-out continuous reinforcing fiber (A) to be impregnated. A method of dispersing the powdered resin on the continuous reinforcing fiber (A) and melting it by heating, a method of forming a film of the resin and heat-laminating it with the continuous reinforcing fiber (A), and a method of dissolving the resin in a solvent and then continuously reinforcing the fiber ( There is a method of impregnating and drying A).

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The embodiments can be changed as appropriate as long as the effects of the invention are exhibited.

[Synthesis Example 1]
Synthesis of 2,2-bis (4-hydroxy-3-methylphenyl) propane / 2,2-bis (4-hydroxyphenyl) propane = 6/4 copolymerized polycarbonate.
2,2-Bis (4-hydroxy-3-methylphenyl) propane (manufactured by Honshu Chemical Industry Co., Ltd.) 6174.7 g (24.12 mol) and 2 in 54.5 L of 9.0 w / w% aqueous sodium hydroxide solution. , 2-Bis (4-hydroxyphenyl) propane (manufactured by Nippon Steel Chemical Co., Ltd.) 4086 g (17.98 mol), 3.8 g of triethylbenzylammonium chloride, and 50.0 g of hydrosulfite were dissolved.
To this, 24 L of methylene chloride was added, and while stirring, 5390 g of phosgene was continuously blown in for 40 minutes while keeping the temperature at 15 ° C.
After the blowing of phosgene is completed, 210 g of pt-butylphenol is added and stirred vigorously to emulsify the reaction solution. After emulsification, 110 ml of triethylamine is added, and the mixture is stirred at a temperature of 20 to 25 ° C. for about 1 hour to polymerize. rice field.

After completion of the polymerization, the reaction solution was separated into an aqueous phase and an organic phase, and the organic phase was neutralized with phosphoric acid. The organic phase was washed with water until the conductivity of the washing water became 10 μS / cm or less. The obtained organic phase was added dropwise to warm water maintained at 62 ° C., and the solvent was evaporated and removed to obtain a white powdery precipitate. The obtained precipitate was filtered and dried at a temperature of 120 ° C. for 24 hours to obtain the desired polycarbonate polymer powder. The weight average molecular weight of the obtained polycarbonate resin (C1) was 31,000.

[Example 1]
25 parts by mass of polycarbonate resin (C1) and methyl ethyl ketone (C1) synthesized from plain weave carbon fiber cloth (manufactured by Arisawa Seisakusho, CFP-3113: mass 200 g / m2, thickness 0.2 mm, fiber length 210 mm, horizontal 300 mm) in Synthesis Example 1 Hereinafter, it may be simply referred to as MEK.) After impregnating a varnish containing 75 parts by mass for 30 seconds, the solvent is removed by drying at 100 ° C. for 1 hour, and the carbon fiber cloth is contained in the polycarbonate resin (C1). Obtained a prepreg with.
Six pieces of this prepreg material were prepared, and the stacked pieces were press-molded using a flat plate-shaped mold heated to 150 ° C. under the conditions of a press time of 5 minutes and a molding pressure of 1.0 MPa. A continuous fiber reinforced polycarbonate resin sheet was obtained.
The obtained sheet was evaluated for bending characteristics (bending elastic modulus, bending strength) according to the method A of JIS K 7074, and the results are shown in Table 1.

[Comparative Example 1]
Plain woven carbon fiber cloth (manufactured by Arisawa Seisakusho, CFP-3113: mass 200 g / m2, thickness 0.2 mm, fiber length 210 mm, horizontal 300 mm) is made of polymethylmethacrylate-styrene (MS) resin (manufactured by Nippon Steel & Sumitomo Metal Chemical Corporation). Estyrene MS-200 ") After impregnating a varnish containing 25 parts by mass and 75 parts by mass of MEK for 30 seconds, the solvent was removed by drying at 100 ° C. for 1 hour, and carbon fiber cloth was arranged in the MS resin. I got a prepreg.
Six pieces of this prepreg material were prepared, and the stacked pieces were press-molded using a flat plate-shaped mold heated to 150 ° C. under the conditions of a press time of 5 minutes and a molding pressure of 1.0 MPa. A continuous fiber reinforced MS resin sheet was obtained.
The obtained sheet was evaluated for bending characteristics (bending elastic modulus, bending strength) according to the method A of JIS K 7074, and the results are shown in Table 1.

[Comparative Example 2]
A bending test piece having a thickness of 1 mm, a width of 15 mm, and a length of 60 mm was prepared by injection molding using carbon short fiber reinforced polyamide (PA) 66 (manufactured by Toray Co., Ltd., Treca short fiber pellet, 3101T40, fiber length of 1 mm or less). A fiber-reinforced PA66 resin sheet was obtained. The cylinder temperature was 290 ° C. and the mold temperature was 80 ° C. The obtained sheet was evaluated for bending characteristics (bending elastic modulus, bending strength) according to the method A of JIS K 7074, and the results are shown in Table 1.

The following can be said from the above-mentioned Example 1 and Comparative Examples 1 and 2.
When the matrix resin is a polycarbonate resin (C1) in CFRTP, the flexural modulus and bending strength are improved as compared with the case where the matrix resin is an MS resin (Example 1, Comparative Example 1). It is considered that the structural unit represented by the formula [1] contributes to the improvement of the flexural modulus and the bending strength.

When the reinforcing fiber is a continuous fiber in CFRTP, the elastic modulus is significantly improved as compared with the case where the reinforcing fiber is a short fiber (Example 1, Comparative Example 2). Even if PA66, which increases the bending strength of the composite material, is used as the matrix resin, it is difficult to obtain an elastic modulus equivalent to that of a light metal when the reinforcing fiber is a short fiber. I understand the importance.

Claims (10)

A fiber-reinforced thermoplastic tree composite material containing a continuous reinforcing fiber (A) and a thermoplastic resin (B), wherein the thermoplastic resin (B) is a polycarbonate containing a structural unit represented by the following formula [1]. Including (C)
The continuous reinforcing fiber (A) is contained in an amount of 1 to 80% by mass, and the thermoplastic resin (B) is contained in an amount of 20 to 99% by mass.
The polycarbonate (C) is 20 mass% or more of the following formula and represented by structure unit of [2], polycarbonate copolymer comprising a structure unit of which is represented by 80 wt% or less of the following formula [3] It contains at least 2,2-bis (4-hydroxy-3-methylphenyl) propane / 2,2-bis (4-hydroxyphenyl) propane = 6/4 copolymerized polycarbonate.
A fiber-reinforced thermoplastic resin composite material, wherein the content ratio of the polycarbonate (C) in the thermoplastic resin (B) is 80 to 100% by mass.

(In the formula [1], R represents a single bond, an alkylene group having 1 to 6 carbon atoms, an arylene group having 6 to 10 carbon atoms, or a cyclic alkylene group having 3 to 8 carbon atoms, and X and Y represent. Each independently represents an alkyl group having 1 to 6 carbon atoms.)

The fiber-reinforced thermoplastic resin composite material according to claim 1, which contains 50 to 75% by mass of the continuous reinforcing fiber (A) and 25 to 50% by mass of the thermoplastic resin (B). The fiber-reinforced thermoplastic resin composite material according to claim 1 or 2, wherein the average fiber length of the continuous reinforcing fibers (A) is 10 mm or more. The fiber-reinforced thermoplastic resin according to any one of claims 1 to 3, wherein the continuous reinforcing fiber (A) contains at least one selected from the group consisting of carbon fiber, glass fiber and aramid fiber. Composite material. The fiber-reinforced thermoplastic resin composite material according to any one of claims 1 to 4, wherein the thermoplastic resin (B) contains a polycarbonate (C) having a weight average molecular weight of 31,000. The fiber-reinforced thermoplastic resin composite material according to any one of claims 1 to 5, wherein the content ratio of the polycarbonate (C) in the thermoplastic resin (B) is 100% by mass. The polycarbonate (C) is a polycarbonate copolymer containing a constitutional unit of which is represented by 40 wt% or more of the above formula [2], fiber-reinforced thermoplastic resin composite according to claim 1 material. A molded product using the fiber-reinforced thermoplastic resin composite material according to any one of claims 1 to 7. The molded product according to claim 8, wherein another transparent resin is laminated on the surface of the fiber-reinforced thermoplastic resin composite material. The molded product according to claim 8 or 9, wherein the bending strength is 300 MPa or more.