WO2011148619A1 - Fiber-reinforced composite material - Google Patents

Abstract

Provided is a fiber-reinforced composite material having improved prepreg shelf life, moldability, light resistance, scratch resistance, and the like. A composite material is formed from a matrix resin and a fiber material. The matrix resin is a thermoplastic acrylic resin obtained using an acrylic polymer, a structural component of which is monomer (a) represented by general formula (1) (where in general formula (1), R¹ is H or CH₃ and R² is a C_1-4 alkyl group). The structural components of the acrylic polymer are, for instance, monomer (a) represented by general formula (1) and glycidyl methacrylate (b). The structural ratio of these components (a) and (b) is preferably within a range of (a):(b) = 70:30 to 99.9:0.1 by weight ratio.

Description

Fiber reinforced composite material

The present invention relates to a fiber reinforced composite material, and relates to a fiber reinforced composite material using a thermoplastic acrylic resin as a matrix resin.

In recent years, fiber reinforced composite materials obtained by combining reinforced fiber materials such as carbon fibers, glass fibers, and aramid fibers with various matrix resins have been widely used in various fields and applications. Conventionally, thermosetting resins such as epoxy resins and polyimide resins have been used as matrix resins (Patent Document 1). However, conventional fiber reinforced composite materials have problems such as insufficient weather resistance, low storage management as a prepreg (short life), long molding time, low productivity, and difficulty in recycling. was there.

On the other hand, fiber reinforced composite materials using thermoplastic resins have been proposed in recent years, and thermoplastic resins are easy to store, have a short molding time, and are easy to recycle. Etc. are advantageous. However, many fiber-reinforced composite materials using thermoplastic resins are inferior in moldability such as low dimensional stability at the time of molding, and are often deteriorated by heat, light, etc. or easily damaged. There was a problem.

Japanese Patent Laid-Open No. 2005-225982

The present invention has been made in view of the above, and by using a specific matrix resin, a fiber-reinforced composite material with improved storage management, moldability, light resistance, scratch strength, and the like as a prepreg has been obtained. The purpose is to provide.

As a result of various studies on the matrix resin, the present inventors have obtained a fiber-reinforced composite material excellent in storage management, moldability, light resistance, and scratch strength of the prepreg by using a specific thermoplastic acrylic resin. As a result, the present invention has been completed.

That is, the fiber-reinforced composite material of the present invention is obtained by combining a fiber material with a thermoplastic acrylic resin as a matrix resin in order to solve the above-mentioned problems. An acrylic polymer having a monomer represented by the formula (1) as a constituent component is used.

However, in the general formula (1), R ¹ represents H or CH ₃ , and R ² represents an alkyl group having 1 to 4 carbon atoms.

As said acrylic polymer, the monomer represented by said (a) general formula (1) and (b) glycidyl methacrylate are made into a structural component, and the structural ratio of these (a) component and (b) component is weight ratio. (A) :( b) = 70: 30 to 99.9: 0.1 can be preferably used.

The acrylic polymer is a polymer blend containing an acrylic polymer comprising (c) at least one selected from acrylic acid, methacrylic acid, and itaconic acid (hereinafter also referred to as monomer (c)), A polymer blend containing the component (c) in a proportion of 0.1 to 20% by weight can also be suitably used.

As the fiber material, it is possible to use at least one selected from a fiber in which the fibers are aligned in one direction, a woven fabric, a knitted fabric, a non-woven fabric, and a braided sland.

As the fiber material, at least one selected from carbon fiber, graphite fiber, silicon carbide fiber, alumina fiber, tungsten carbide fiber, boron fiber, glass fiber, aramid fiber, polyamide fiber, and polyester fiber is used. be able to.

When the fiber material is a carbon fiber, the fiber reinforced composite material of the present invention preferably has a bending strength of 300 MPa or more in accordance with JIS K 7074.

Further, the matrix resin preferably has a pencil hardness of F or more according to JIS K 5600-5-4.

According to the present invention, by using the above-mentioned predetermined thermoplastic acrylic resin as a matrix resin, light resistance and scratch strength are remarkably excellent, and fiber management with improved storage management and moldability when made into a prepreg is achieved. A composite material can be provided. Moreover, heat resistance can be improved by selecting an acrylic monomer to be copolymerized.

1. Reinforcing fiber material In the present invention, the reinforcing fiber material refers to a material in which fiber materials are arranged in a sheet in one direction, a laminate of these materials, for example, an orthogonal layer, and a fiber material is molded into a fabric such as a woven fabric, a knitted fabric, or a nonwoven fabric All sland-like items such as knitting and braiding are included. As the reinforcing fiber material, there are fiber materials made of inorganic fibers, organic fibers, metal fibers, or a mixture thereof. Specific examples of the inorganic fiber include carbon fiber, graphite fiber, silicon carbide fiber, alumina fiber, tungsten carbide fiber, boron fiber, and glass fiber. Examples of organic fibers include aramid fibers, polyamide fibers, and polyester fibers. These reinforcing fibers can also be used in combination of multiple types.

2. Matrix resin In the present invention, a thermoplastic acrylic resin is used as the matrix resin. By using a thermoplastic acrylic resin as the matrix resin, physical properties such as light resistance and scratching strength, storage management in the case of prepreg, resin fluidity during lamination / molding press, interlayer adhesion of laminated products, etc. An excellent fiber reinforced composite material is obtained.

As the thermoplastic acrylic resin, an acrylic polymer containing (a) a monomer represented by the general formula (1) as a constituent component is used.

However, in the general formula (1), R ¹ represents H or CH ₃ , and R ² represents an alkyl group having 1 to 4 carbon atoms.

The monomer represented by the general formula (1) (hereinafter also referred to as monomer (a)) can be used alone or in combination of two or more. Preferable examples of this monomer include methyl methacrylate and ethyl methacrylate.

The monomer represented by the general formula (1) is desirably contained in an amount of 10% by weight or more in the whole acrylic polymer used as the matrix resin.

Preferred embodiments of the thermoplastic resin used in the present invention include the following, but are not limited to the following.

(1) Acrylic polymer (A) comprising monomer (a) as a constituent component
An acrylic polymer consisting only of one or more monomers (a) can also be suitably used as the matrix resin.

The acrylic polymer (A) may be a polymer blend in which two or more acrylic polymers (A) having different monomer structures are mixed.

(2) Acrylic polymer (B) comprising monomer (a) and glycidyl methacrylate (b) as constituent components
By copolymerizing the monomer (a) with a functional vinyl monomer containing an epoxy such as glycidyl methacrylate, the adhesion to the fiber material can be further improved, and the bending strength of the composite material is also improved. be able to.

The constituent ratio of the monomer (a) and glycidyl methacrylate (b) is preferably in the range of (a) :( b) = 70: 30 to 99.9: 0.1 by weight ratio, ) :( b) = more preferably in the range of 80:20 to 90:10.

This acrylic polymer (B) may also be a polymer blend obtained by mixing two or more acrylic polymers (B) having different monomer structures.

(3) A polymer of the acrylic polymer (A) or (B) and an acrylic polymer (C) containing at least one selected from acrylic acid, methacrylic acid, and itaconic acid (monomer (c)) as a constituent component Blend The acrylic polymer (C) obtained by polymerizing a vinyl monomer containing a carboxyl group such as acrylic acid can be blended with the acrylic polymer used in the present invention. By blending the acrylic polymer (C), the adhesion to the fiber material and the bending strength of the composite material can be further improved, and the heat resistance can also be improved.

Any one kind of acrylic acid, methacrylic acid and itaconic acid may be used, or two or more kinds may be mixed and used.

In order to prepare a polymer blend with the acrylic polymer (A) or (B), an acrylic polymer (C) obtained by polymerizing a carboxyl group-containing vinyl monomer is produced separately from the acrylic polymer (A) or (B). Then, it may be blended according to a conventional method.

The blend ratio of the acrylic polymer (C) is preferably such that the proportion of the component (c) in the polymer blend is within the range of 0.1 to 20% by weight, and within the range of 0.5 to 10% by weight. It is more preferable that

The acrylic polymer (C) itself may be a polymer blend in which two or more acrylic polymers (C) having different monomer structures are mixed.

In addition, the thermoplastic acrylic resin used in the present invention may contain a polymer other than the acrylic polymer as long as it does not deviate from the object of the present invention.

Each thermoplastic acrylic resin used as the matrix resin preferably has a glass transition point (Tg) of 60 ° C. or higher from the viewpoints of moldability, heat resistance of the molded product, storage controllability, strength, and the like.

3. Manufacturing method of fiber reinforced composite material etc. When using the said thermoplastic acrylic resin as a matrix resin, a solvent can be used as needed. Examples of solvents that can be used include methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), isopropyl acetate, propyl acetate, butyl acetate, ethyl acetate, xylene, toluene, dimethylformamide (DMF), and the like.

The method for producing a fiber-reinforced composite material by compositing the fiber material and the matrix resin is not particularly limited, and can be produced according to a conventionally used method. That is, by adding a polymerization initiator such as azobisisobutyronitrile to the matrix resin, and appropriately using a method such as dipping (impregnation) or coating, the matrix resin is infiltrated into the fiber material, heated, etc. The resin can be cured.

When the fiber material is carbon fiber, it is preferable that the bending strength (JIS K 7074) of the fiber reinforced composite material is 300 MPa or more in consideration of use for structural materials and decoration (interior) applications. By using the matrix resin, the fiber reinforced composite material of the present invention can satisfy the requirement for bending strength while improving light resistance.

In addition, when used for structural materials and decorative applications as described above, it is preferable that the scratch strength of the cured matrix resin covering the surface thereof is such that the pencil hardness (JIS K 5600-5-4) is F or more. The matrix resin used in the present invention can also satisfy this requirement.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples. In the following description, “parts” means “parts by weight” unless otherwise specified.

In the following examples, the following [1] to [4] were used as physical property evaluation methods.

[1] The glass transition temperature (Tg) was calculated from Tgn of each constituent polymer constituting the binder resin according to the following Fox equation.
Fox formula: 100 / Tg = Σ (Wn / Tgn)
Tg: Calculated polymer Tg (absolute temperature)
Wn: weight fraction of monomer n (%)
Tgn: Glass transition temperature (absolute temperature) of homopolymer of monomer n

The Tg value (Tgn) of the homopolymer of monomer n is, for example, the technical data of monomer manufacturers such as Mitsubishi Rayon Co., Ltd. (First edition). For example, polymethyl methacrylate (PMMA) (105 ° C.), polyisobutyl methacrylate (PIBMA) (48 ° C.), poly lauryl methacrylate (−65 ° C.), poly 2-ethoxyethyl methacrylate (−31 ° C.), polyacrylonitrile (100 ° C.).

[2] Pencil hardness: Measured according to JIS K 5600-5-4.
[3] Bending strength: Measured according to JIS K7074.
[4] Light resistance: An accelerated weather resistance test was performed in accordance with JIS K 5600-7-7. Those that were not visually discolored were rated as “no problem”.

[Examples 1 to 3] (Examples using an acrylic polymer (A) comprising the monomer (a) represented by the general formula (1))
150.0 parts by weight of MIBK in a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen introduction tube, 100 parts by weight of each monomer shown in Table 1 for each example, 0.5 weight of n-dodecyl mercaptan The reactor was heated to 70 ° C. and 0.25 parts by weight of azobisisobutyronitrile was added to initiate polymerization. The reactor was kept at 70 ° C., and after 5 hours, 0.1 part by weight of azobisisobutyronitrile was further added, and the reactor was kept at 75 ° C. and stirred for 3 hours to obtain a thermoplastic acrylic resin. . About the obtained resin, Tg was measured according to said [1].

The obtained resin was transferred to a tray having a width of 350 mm, a length of 500 mm, and a depth of 60 mm, and carbon fiber fabric (CO 6343B, manufactured by Toray Industries, Inc.) was dipped and impregnated into the resin in the tray. It adjusted so that the adhesion amount of resin solid content might be set to 200 +/- 5g / m < ² >. After dipping impregnation, it was dried in an oven at 80 ° C. for 30 minutes. The obtained carbon fiber reinforced composite material was laminated so that the thickness after pressing was 2 ± 0.4 mm, and heated with a heating / cooling integrated compression molding machine (SFA-37HHC, manufactured by Kondo Metal Industry Co., Ltd.). Lamination press processing was performed under the conditions of a temperature of 200 ° C. and a pressure of 30 kgf / cm ² to obtain a carbon fiber reinforced composite material of a plate-like laminate. The obtained carbon fiber reinforced composite material laminate was measured or evaluated in the above [2] to [4]. The results are shown in Table 1.

[Examples 4 to 8] (Examples using an acrylic polymer (B) composed of the monomer (a) represented by the general formula (1) and glycidyl methacrylate)
A thermoplastic acrylic resin was obtained in the same manner as in Examples 1 to 3 except that 100 parts by weight of each monomer shown in Table 2 was used. Tg of the obtained resin was measured.

Using the obtained resin, a plate-like carbon fiber reinforced composite material was obtained in the same manner as in the above example. The obtained carbon fiber reinforced composite material laminate was measured or evaluated in the above [2] to [4]. The results are shown in Table 2.

[Examples 9 to 17] (Examples using a polymer blend of acrylic polymer (B) and acrylic polymer (C))
Among the monomers shown in Table 3, the same operation as in Examples 1 to 3 was carried out using monomer (a) and glycidyl methacrylate to obtain acrylic polymer (B). Apart from this, an acrylic polymer (C) was obtained in the same manner as in Examples 1 to 3, except that the monomer (c) was used. The obtained acrylic polymer (B) and acrylic polymer (C) were blended so that the monomer ratio was the ratio shown in Table 3, and Tg of the obtained polymer blend was measured.

Using the obtained resin, a plate-like carbon fiber reinforced composite material was obtained in the same manner as in the above example. The obtained carbon fiber reinforced composite material laminate was measured or evaluated in the above [2] to [4]. The results are shown in Table 3.

[Comparative Example 1]
Using a prepreg using epoxy resin as a matrix resin (F6343B-05P, manufactured by Toray Industries, Inc.), laminated in a plate shape so that the thickness becomes 2 ± 0.4 mm, cured at a heating temperature of 130 ° C., A carbon fiber reinforced composite material was obtained. When the obtained carbon fiber reinforced composite material laminate was subjected to the light resistance evaluation of [4] above, discoloration was observed.

[Comparative Example 2]
A prepreg using nylon 66 as a matrix resin (made by BOND LAMINATES, dynalite201) is laminated in a plate shape so that the thickness is 2 ± 0.4 mm, and the heating temperature is 130 ° C. and the pressure is 30 kgf / cm ² . Lamination press processing was performed to obtain a carbon fiber reinforced composite material of a plate-like laminate. When the obtained carbon fiber reinforced composite material laminate was subjected to the light resistance evaluation of [4] above, discoloration was observed.

[Comparative Example 3]
A prepreg using a polyurethane resin as a matrix resin (BOND LAMINATES, dynalite208) is used, laminated in a plate shape so that the thickness is 2 ± 0.4 mm, and laminated under the conditions of a heating temperature of 130 ° C. and a pressure of 30 kgf / cm ^2. Press processing was performed to obtain a carbon fiber reinforced composite material of a plate-like laminate. When the obtained carbon fiber reinforced composite material laminate was subjected to the light resistance evaluation of [4] above, discoloration was observed.

The molded product of fiber reinforced composite material obtained by the present invention can be applied as parts of vehicles, aircraft, boats, windmills, waterwheels, household electrical appliances, production machinery, housing equipment, furniture, watches, helmets, stationery. Yes, application development in a wider range can be expected.

Claims (7)

Combining fiber material with thermoplastic acrylic resin as matrix resin,
A fiber-reinforced composite material, wherein an acrylic polymer containing (a) a monomer represented by the general formula (1) as a constituent component is used as the thermoplastic acrylic resin.

However, in the general formula (1), R ¹ represents H or CH ₃ , and R ² represents an alkyl group having 1 to 4 carbon atoms. The acrylic polymer comprises (a) the monomer represented by the general formula (1) and (b) glycidyl methacrylate as constituent components, and the constituent ratio of these (a) component and (b) component is expressed by weight ratio. 2. The fiber-reinforced composite material according to claim 1, wherein (a) :( b) = 70: 30 to 99.9: 0.1. The acrylic polymer is a polymer blend containing an acrylic polymer comprising at least one selected from (c) acrylic acid, methacrylic acid, and itaconic acid, and the component (c) is contained in the polymer blend. 3. The fiber-reinforced composite material according to claim 1, wherein the fiber-reinforced composite material is contained in a proportion of 0.1 to 20% by weight. The fiber material according to any one of claims 1 to 3, wherein the fiber material is at least one selected from one in which fibers are arranged in a sheet shape in one direction, a woven fabric, a knitted fabric, a nonwoven fabric, and a braided sland. The fiber-reinforced composite material according to any one of the above. The fiber material is at least one selected from carbon fiber, graphite fiber, silicon carbide fiber, alumina fiber, tungsten carbide fiber, boron fiber, glass fiber, aramid fiber, polyamide fiber, and polyester fiber. The fiber-reinforced composite material according to claim 4. 6. The fiber-reinforced composite material according to claim 5, wherein when the fiber material is carbon fiber, the bending strength in accordance with JIS K7074 is 300 MPa or more. The fiber-reinforced composite material according to any one of claims 1 to 6, wherein the matrix resin has a pencil hardness according to JIS K 5600-5-4 of F or higher.