WO2022130728A1 - Carbon fiber composite, and method for manufacturing carbon fiber composite - Google Patents

Abstract

The present invention provides a carbon fiber composite that has high impact resistance and excellent moldability while using a semi-aromatic polyamide resin. The carbon fiber composite is characterized by comprising carbon fibers and a matrix portion comprising a resin composition, wherein: the resin composition has a sea-island structure comprising a continuous phase of a polyamide resin (A) and a non-continuous phase of a polyolefin (B); the polyamide resin (A) includes only a semi-aromatic polyamide resin (A1); the polyolefin (B) includes an unmodified polyolefin (B1) and a modified polyolefin (B2); and the viscosity of the resin composition measured in accordance with JIS K 7199 at a temperature of 300ºC and a shear rate of 12.16 s^-1 is 900-4000 Pa·s.

Description

Carbon fiber complex and method for manufacturing carbon fiber complex

The present invention relates to a carbon fiber composite and a method for producing the carbon fiber composite.

It is known that impact resistance is improved by introducing and dispersing an elastomer domain in a polyamide resin. In this regard, in order to disperse the domain of the elastomer, a compatibilizer such as maleic anhydride is usually required. By using the above compatibilizer, a part of the polyamide resin and the compatibilizer can be reacted to form a surfactant-like structure having both functions of polyamide and elastomer. Because it can be done.

As a technique related to the above, for example, Patent Document 1 describes heat using a plant-derived polyamide resin such as PA11 (a condensed polymer of a monomer derived from castor oil), a polyolefin resin, and a compatibilizer at predetermined ratios. It is disclosed that the plastic resin composition is excellent in impact resistance and rigidity.

Japanese Unexamined Patent Publication No. 2013-147646

By the way, in recent years, as a polyamide resin having excellent water resistance and heat resistance, a so-called semi-aromatic polyamide resin (that is, a polycondensate of a dicarboxylic acid containing at least an aromatic dicarboxylic acid and a non-aromatic diamine, or a non-aromatic dicarboxylic acid) A polycondensate of an acid and a diamine containing at least an aromatic diamine) has been attracting attention. In particular, this semi-aromatic polyamide resin tends to have a high glass transition temperature due to its molecular structure, and is therefore positioned as an important material expected to be developed in the fields of automobiles and aircraft.

Here, in general, when a compatibilizer is added to a polyamide resin and an elastomer, the apparent molecular weight tends to increase and the viscosity tends to increase. In this regard, the semi-aromatic polyamide resin may need to be heated to an extremely high temperature (for example, over 300 ° C.) in the process of processing, and at this time, the increase in viscosity is further promoted, and the gel is gelled during domain dispersion. It turned out that the problem of becoming a resin arises. Such gelation may make molding difficult or impossible.

When conventional polyamide resins such as polyamide 6 and polyamide 66 are used, it is not necessary to raise the processing temperature so much, so that the problem caused by the increase in viscosity as described above has hardly been reached so far.

Furthermore, in recent years, with the increasing demand for sheet materials (fiber composites) made by impregnating reinforcing fibers such as carbon fibers with a sheet-shaped matrix resin, which is also called "composite prepreg", the sheet is made from a polyamide resin. Is also required. However, in the sheet molding using the above-mentioned semi-aromatic polyamide resin, holes and coarse resin lumps frequently occur, so that the desired sheet cannot be stably molded.

Therefore, it is an object of the present invention to provide a carbon fiber composite having high impact resistance and excellent moldability while using a semi-aromatic polyamide resin.
Another object of the present invention is to provide a method for producing a carbon fiber composite having high impact resistance and excellent moldability while using a semi-aromatic polyamide resin.

The gist structure of the present invention that solves the above problems is as follows.

The carbon fiber composite of the present invention is a carbon fiber composite containing carbon fibers and a matrix portion made of a resin composition.
The resin composition has a sea-island structure consisting of a continuous phase of the polyamide resin (A) and a discontinuous phase of the polyolefin (B).
The polyamide resin (A) contains only the semi-aromatic polyamide resin (A1), and contains only the semi-aromatic polyamide resin (A1).
The polyolefin (B) contains an unmodified polyolefin (B1) and a modified polyolefin (B2).
The resin composition is characterized in that the viscosity measured at a temperature of 300 ° C. and a shear rate of 12.16s ^-1 is 900 Pa · s or more and 4000 Pa · s or less in accordance with JIS K 7199.

Further, the method for producing a carbon fiber composite of the present invention is a method for producing a carbon fiber composite containing carbon fibers and a matrix portion composed of a resin composition.
A sheet forming step of forming a sheet having a thickness of 10 μm or more and 500 μm or less from the resin composition containing the polyamide resin (A) and the polyolefin (B).
A composite acquisition step of contacting the sheet with the carbon fibers to obtain a carbon fiber composite containing the carbon fibers and a matrix portion made of the resin composition is provided.
The polyamide resin (A) contains only a semi-aromatic polyamide resin (A1), and the polyolefin (B) contains an unmodified polyolefin (B1) and a modified polyolefin (B2).

According to the present invention, it is possible to provide a carbon fiber composite having high impact resistance and excellent moldability while using a semi-aromatic polyamide resin.
Further, according to the present invention, it is possible to provide a method for producing a carbon fiber composite having high impact resistance and excellent moldability while using a semi-aromatic polyamide resin.

Hereinafter, the carbon fiber complex of the present invention and a method for producing the same will be described in detail as examples based on the embodiments thereof.

<Carbon fiber complex>
The carbon fiber complex of one embodiment of the present invention (hereinafter, may be referred to as “complex of the present embodiment”) includes a carbon fiber and a matrix portion composed of a resin composition. And the complex of this embodiment is
The resin composition has a sea-island structure consisting of a continuous phase of the polyamide resin (A) and a discontinuous phase of the polyolefin (B) (structural requirement).
The polyamide resin (A) contains only a semi-aromatic polyamide resin (A1), and the polyolefin (B) contains an unmodified polyolefin (B1) and a modified polyolefin (B2) (composition requirement), and
The viscosity of the resin composition measured at a temperature of 300 ° C. and a shear rate of 12.16s ^-1 (hereinafter, may be simply referred to as “300 ° C. viscosity”) in accordance with JIS K 7199 is 900 Pa · s or more. Each is characterized by being 4000 Pa · s or less (viscosity requirement).

In the present specification, the "semi-aromatic polyamide resin" contains at least a polycondensate of a dicarboxylic acid containing at least an aromatic dicarboxylic acid and a non-aromatic diamine, or at least a non-aromatic dicarboxylic acid and an aromatic diamine. It shall refer to a polycondensate with a diamine.

In the composite of the present embodiment, as described above, only the semi-aromatic polyamide resin (A1) is used as the polyamide resin (A) with respect to the resin composition of the matrix portion, and the continuous phase of the polyamide resin (A) and the continuous phase of the polyamide resin (A) are used. A sea-island structure is formed by the discontinuous phase of the polyolefin (B). As described above, the complex of the present embodiment can exhibit high impact resistance due to the characteristics of the semi-aromatic polyamide resin (A1) itself in the matrix portion and the predetermined sea-island structure.
Whether or not the sea-island structure is formed can be confirmed by observing with a microscope such as an atomic force microscope.

Further, the resin composition has a viscosity at 300 ° C. adjusted to a certain range (900 Pa · s or more and 4000 Pa · s or less) while achieving the above-mentioned structural requirements. Excellent. Even if the resin composition satisfies the above-mentioned structural requirements and composition requirements, if the viscosity at 300 ° C. exceeds 4000 Pa · s, holes and coarse resin lumps are generated during molding, which is high. Formability cannot be guaranteed. Further, even if the resin composition satisfies the above-mentioned structure and composition requirements, if the viscosity at 300 ° C. is less than 900 Pa · s, problems such as pulsation occur during sheet molding, and the thickness of the sheet is constant. Cannot be made. Further, when the viscosity of the resin composition at 300 ° C. is less than 900 Pa · s, there is a possibility that high impact resistance cannot be exhibited as a result of an undesired increase in diameter and / or decrease in the diameter of the domain. ..

From the same viewpoint as above, the viscosity of the resin composition at 300 ° C. is preferably 3000 Pa · s or less, more preferably 2500 Pa · s or less, still more preferably 2000 Pa · s or less, and 1800 Pa · s or less. -It is more preferable that it is s or less.

The complex of the present embodiment is not particularly limited, but includes at least the following two forms.
(1) Composite prepreg (2) A laminated body in which a plurality of fiber layers in which reinforcing fibers containing carbon fibers are arranged and a plurality of resin layers containing a polyamide resin (A) and a polyolefin (B) are laminated.

The composite prepreg of the above (1) is a sheet material obtained by impregnating a reinforcing fiber containing carbon fiber with a matrix resin containing a polyamide resin (A) and a polyolefin (B). The reinforcing fiber is preferably a layer of an aggregate of fibers arranged so that the major axis directions of two or more fibers are oriented in a specific direction. Further, the complex of the present embodiment also includes the form of a laminated body in which a plurality of composite prepregs are laminated with the above (1) as a repeating unit.

The above (2) includes not only a form in which a fiber layer and a resin layer are laminated one by one, but also a form in which a plurality of fiber layers and a resin layer are laminated. Further, the fiber layer is preferably a layer of an aggregate of fibers arranged so that the major axis directions of two or more fibers are oriented in a specific direction.

Further, the complex of the present embodiment also includes the form of a laminated body in which the above (1) and the above (2) are mixed.

As a suitable structural requirement, the resin composition preferably has a discontinuous phase circle-equivalent diameter (domain diameter) of 0.3 μm or more, and preferably 3.0 μm or less. When the domain diameter is within the above range, high impact resistance can be exhibited more effectively. More preferably, the circle-equivalent diameter (domain diameter) of the discontinuous phase is 0.5 μm or more, 0.8 μm or more, 1.2 μm or more, and 2.8 μm or less and 2.7 μm or less.
The domain diameter can be obtained as an average value of circle-equivalent diameters (diameters of circles of the same area) for all discontinuous phases observed from an image region of 30 μm × 30 μm of the resin composition.

The means for achieving the above-mentioned structural requirements and viscosity requirements is not particularly limited, but for example,
(1) The types of the semi-aromatic polyamide resin (A1), the unmodified polyolefin (B1) and the modified polyolefin (B2) are appropriately selected.
(2) The blending ratios of the semi-aromatic polyamide resin (A1), the unmodified polyolefin (B1) and the modified polyolefin (B2) are appropriately selected.
(3) Appropriately select the kneading conditions (addition timing of each raw material, kneading time, rotation speed of kneading device, screw shape, resin temperature at the time of kneading).
Etc., and the above resin composition can be obtained based on these combined actions.

Hereinafter, the components contained in the above resin composition will be described.

(Polyamide resin (A))
The above-mentioned resin composition contains a polyamide resin (A), and the polyamide resin (A) contains only a semi-aromatic polyamide resin (A1) as described above. This is because if a polyamide resin other than the semi-aromatic polyamide resin (A1), for example, an aliphatic polyamide resin is further used as the polyamide resin (A), the impact resistance may be deteriorated. The semi-aromatic polyamide resin (A1) may be used alone or in combination of two or more.

The semi-aromatic polyamide resin (A1) includes a polycondensate of a dicarboxylic acid containing at least an aromatic dicarboxylic acid and a non-aromatic diamine, and a weight of a diamine containing at least a non-aromatic dicarboxylic acid and an aromatic diamine. Examples include condensates. Specifically, for example, polyamide 4T, polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), polyhexamethylenenaphthalamide (polyamide 6N), polynonamethylene terephthalamide (polyamide 6N). 9T), polynonamethylene isophthalamide (polyamide 9I), polynonamethylene naphthalamide (polyamide 9N), poly (2-methyloctamethylene terephthalamide) (polyamide M8T), poly (2-methyloctamethyleneisophthalamide). ) (Polyamide M8I), Poly (2-methyloctamethylenenaphthalamide) (Polyamide M8N), Polytrimethylhexamethylene terephthalamide (Polyamide TMHT), Polytrimethylhexamethyleneisophthalamide (Polyamide TMHI), Polytrimethylhexamethylenenaphthal Ramide (polyamide TMHN), polydecamethylene terephthalamide (polyamide 10T), polydecamethylene isophthalamide (polyamide 10I), polydecamethylene naphthalamide (polyamide 10N), polyundecamethylene terephthalamide (polyamide 11T), Polyundecamethylene isophthalamide (polyamide 11I), polyundecamethylene naphthalamide (polyamide 11N), polydodecamethylene terephthalamide (polyamide 12T), polydodecamethylene isophthalamide (polyamide 12I), polydodecamethylene naphthalamide (Polyamide 12N), polyamide MXD6 (PAMXD6) and the like are examples.

Examples of the aromatic dicarboxylic acid include aromatic dicarboxylic acids having 8 to 20 carbon atoms, and more specifically, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, 2-chloroterephthalic acid, and 2-methylterephthalic acid. , 5-Methylisophthalic acid, 5-sodiumsulfoisophthalic acid and the like. These aromatic dicarboxylic acids may be used alone or in combination of two or more. Further, the above-mentioned aromatic dicarboxylic acid may be unsubstituted, and various substituents (for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl) may be used. It may be substituted with an alkyl group having 1 to 4 carbon atoms such as a group).

On the other hand, examples of the dicarboxylic acid (non-aromatic dicarboxylic acid) other than the aromatic dicarboxylic acid include a linear or branched aliphatic dicarboxylic acid having 3 to 20 carbon atoms and an alicyclic structure having 3 to 10 carbon atoms. Examples thereof include alicyclic dicarboxylic acids. The dicarboxylic acids other than these aromatic dicarboxylic acids may be used alone or in combination of two or more.

Examples of the linear or branched aliphatic dicarboxylic acid having 3 to 20 carbon atoms include malonic acid, dimethylmalonic acid, succinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylglutaric acid, 2, 2-diethylsuccinic acid, 2,3-diethylglutaric acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, suberic acid, azelaic acid, sevacinic acid, Examples thereof include dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosandioic acid, diglycolic acid and the like.

Examples of the alicyclic dicarboxylic acid having an alicyclic structure having 3 to 10 carbon atoms include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,3-cyclopentanedicarboxylic acid. .. The alicyclic dicarboxylic acid contains trans and cis geometric isomers. For example, as the 1,4-cyclohexanedicarboxylic acid as the raw material monomer, either a trans form or a cis form may be used, or a mixture containing the trans form and the cis form in various ratios may be used. Further, the alicyclic dicarboxylic acid described above may be unsubstituted and may have various substituents (eg, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-. It may be substituted with an alkyl group having 1 to 4 carbon atoms such as a butyl group).

Examples of the aromatic diamine include metaxylylenediamine, orthoxylylenediamine, paraxylylenediamine and the like. These aromatic diamines may be used alone or in combination of two or more.

On the other hand, examples of diamines other than aromatic diamines (non-aromatic diamines) include linear or branched aliphatic diamines and alicyclic diamines. Diamines other than these aromatic diamines may be used alone or in combination of two or more.

Examples of the linear aliphatic diamine include ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine (nonanediamine), decamethylenediamine, and undecamethylene. Examples thereof include diamine, dodecamethylenediamine and tridecamethylenediamine.

Examples of the branched aliphatic diamine include 2-methylpentamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2-methyloctamethylenediamine, 2,4-dimethyloctamethylenediamine and the like.

Examples of the alicyclic diamine include 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, 1,3-cyclopentanediamine and the like.

Among these, as the diamine other than the aromatic diamine (non-aromatic diamine), a diamine having 7 to 12 carbon atoms is preferable. By using these diamines having 7 to 12 carbon atoms as a monomer, the stability of the obtained semi-aromatic polyamide resin (A1) at the time of melting and, by extension, the moldability can be further improved. From the same viewpoint, as the diamine other than the aromatic diamine (non-aromatic diamine), 1,9-nonanediamine and 1,10-decamethylenediamine are more preferable, and 1,9-nonanediamine is further preferable.

The semi-aromatic polyamide resin (A1) is preferably a polycondensate of a dicarboxylic acid containing at least an aromatic dicarboxylic acid and a non-aromatic diamine from the viewpoint of more effectively improving heat resistance and impact resistance. ..

In the above polycondensate, the ratio of the aromatic dicarboxylic acid to the dicarboxylic acid is preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more. As a result, the glass transition temperature can be increased and the impact resistance can be further effectively improved.

Further, in the above polycondensate, the ratio of the diamine having 7 to 12 carbon atoms in the non-aromatic diamine is preferably 20 mol% or more, preferably 30 mol% or more, from the viewpoint of the balance between moldability and heat resistance. It is more preferably 40 mol% or more, and particularly preferably 45 mol% or more.

The semi-aromatic polyamide resin (A1) preferably has a melting point of 280 ° C. or lower. As a result, when preparing the resin composition, it is possible to suppress an excessive increase in the reaction rate of the modified polyolefin (B2), and more effectively suppress a significant increase in viscosity and eventually deterioration of moldability.

Examples of the method for producing the semi-aromatic polyamide resin (A1) include the following various methods.
(1) A method in which an aqueous solution of a dicarboxylic acid and a diamine or a suspension of water is heated and polymerized while maintaining a molten state (thermal melt polymerization method).
(2) A method of increasing the degree of polymerization of a polyamide obtained by a hot melt polymerization method while maintaining a solid state at a temperature below its melting point (hot melt polymerization / solid phase polymerization method).
(3) A method of heating an aqueous solution of a dicarboxylic acid and a diamine or a suspension of water to precipitate a prepolymer (prepolymer method).
(4) A method of increasing the degree of polymerization by further melting the prepolymer precipitated by heating an aqueous solution of a dicarboxylic acid and a diamine or a suspension of water with an extruder such as a kneader (prepolymer / extrusion polymerization method). )
(5) A method of increasing the degree of polymerization of a prepolymer precipitated by heating an aqueous solution of a dicarboxylic acid and a diamine or a suspension of water while maintaining a solid state at a temperature below its melting point (prepolymer / solid phase weight). legal)
(6) A method of polymerizing a dicarboxylic acid and a diamine or a mixture thereof while maintaining a solid state (solid phase polymerization method).
(7) Method of polymerizing using a dicarboxylic acid halide component equivalent to a dicarboxylic acid and a diamine component (solution method)

Among these, as a method for producing the semi-aromatic polyamide resin (A1), (1) Fused Deposition Modeling Method or (2) Fused Deposition Modeling / Solid Phase Polymerization Method is preferable because the obtained polyamide resin has an excellent color tone. .. The polymerization form may be a batch type or a continuous type. The polymerization apparatus is not particularly limited, and examples thereof include known apparatus such as an autoclave type reactor, a tumbler type reactor, and an extruder type reactor such as a kneader.

The amount of added mol of dicarboxylic acid and the amount of added mol of diamine are preferably about the same in order to increase the molecular weight. Considering the amount of diamine escaping to the outside of the reaction system during the polymerization reaction in the mol ratio, the ratio of the amount of added mol of diamine to the total amount of added mol of dicarboxylic acid is 0.90 (diamine / dicarboxylic acid). The above is preferable, 0.95 or more is more preferable, 0.98 or more is further preferable, 1.20 or less is preferable, and 1.10 or less is more preferable. It is preferably 1.05 or less, and more preferably 1.05 or less.

When polymerizing a polyamide resin from a dicarboxylic acid and a diamine, a known end-capping agent can be used for adjusting the molecular weight. Examples of the terminal encapsulant include acid anhydrides such as monocarboxylic acid, monoamine and phthalic anhydride, monoisocyanate, monoacid halides, monoesters and monoalcohols, and examples thereof include monoalcohols and the like from the viewpoint of thermal stability. , Monocarboxylic acid and monoamine are preferred. The terminal encapsulant may be used alone or in combination of two or more.

(Polyolefin (B))
The resin composition contains a polyolefin (B), and the polyolefin (B) contains an unmodified polyolefin (B1) and a modified polyolefin (B2) as described above. By using at least the modified polyolefin (B2) as the polyolefin (B), it is possible to increase the tendency of the domain of the polyolefin (B) to be dispersed in the continuous phase of the semi-aromatic polyamide resin (A1). Further, by using the unmodified polyolefin (B1) in combination as the polyolefin (B), the viscosity can be optimized. The unmodified polyolefin (B1) and the modified polyolefin (B2) may be used alone or in combination of two or more.

Examples of the unmodified polyolefin (B1) include ethylene homopolymers; ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-1-hexene copolymers, and ethylene-1-octene copolymers. Ethylene-α-olefin copolymer such as ethylene-4-methyl-1-pentene copolymer; propylene homopolymer; propylene-α-olefin copolymer such as propylene-1-butene copolymer; α-olefin Polymers of each other; Polymers of monomers other than α-olefins that can be copolymerized with α-olefins and α-olefins; styrene-ethylene / butylene-styrene copolymers, styrene-propylene / butylene-styrene Copolymer; etc. Examples of the α-olefin include propylene, 1-butene, isobutylene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, 1-octadecene, 4 Examples thereof include α-olefins having 3 to 20 carbon atoms such as -methyl-1-pentene. Examples of the monomer other than the α-olefin copolymerizable with the above α-olefin include vinyl acetate, maleic acid, vinyl alcohol, methacrylic acid, methyl methacrylate, ethyl methacrylate, methyl acrylate, and ethyl acrylate. And so on. Among these, as the unmodified polyolefin (B1), an ethylene homopolymer, an ethylene-α-olefin copolymer, a propylene homopolymer; and a propylene-α-olefin copolymer are more preferable.

The modified polyolefin (B2) is a modified version of an unmodified polyolefin, and more specific examples thereof include acid-modified polyolefin, epoxy-modified polyolefin, and glycidyl-modified polyolefin. In particular, as the modified polyolefin (B2), an acid-modified polyolefin is preferable. The acid-modified polyolefin is an acid-modified polyolefin with an unsaturated carboxylic acid or an acid anhydride thereof. Specific examples of unsaturated carboxylic acid or acid anhydride thereof include maleic acid, fumaric acid, itaconic acid, acrylic acid, methacrylic acid, cis-4-cyclohexene-1,2-dicarboxylic acid, maleic anhydride, and itaconic anhydride. , Sis-4-cyclohexene-1,2-dicarboxylic acid anhydride and the like. In particular, as the unsaturated carboxylic acid or its acid anhydride, maleic anhydride or itaconic anhydride is preferable, and maleic anhydride is more preferable. Derivatives such as acid amides and acid esters can also be used in place of unsaturated carboxylic acids or acid anhydrides thereof.

Specific examples of the polyolefin before modification of the modified polyolefin (B2) are the same as those described above for the unmodified polyolefin (B1). However, as the polyolefin constituting the modified polyolefin (B2), an ethylene homopolymer, an ethylene-α-olefin copolymer, a propylene homopolymer; and a propylene-α-olefin copolymer are more preferable.

In the above resin composition, the average acid value of the polyolefin (B) is preferably 0.1 mgKOH / g or more and 3.0 mgKOH / g or less. When the average acid value of the polyolefin (B) is 0.1 mgKOH / g or more, the viscosity is appropriately increased, and the domain diameter of the discontinuous phase is suppressed from being excessively coarsened to effectively improve the impact resistance. Can be made to. Further, when the average acid value of the polyolefin (B) is 3.0 mgKOH / g or less, an excessive increase in viscosity is suppressed, good moldability is more reliably maintained, and the domain diameter of the discontinuous phase is appropriately adjusted. It can be maintained and the deterioration of impact resistance can be suppressed more effectively. From the same viewpoint, the average acid value of the polyolefin (B) is more preferably 0.3 mgKOH / g or more, further preferably 0.5 mgKOH / g or more, and 2.0 mgKOH / g or less. It is more preferably present, and further preferably 1.6 mgKOH / g or less.
The average acid value of the polyolefin (B) can be calculated as follows. For example, the unmodified polyolefin (B1) (acid value is 0 mgKOH / g) is a part by mass, the first modified polyolefin (B2) having an acid value of x (mgKOH / g) is b by mass, and the acid value is y ( When the second modified polyolefin (B3) of mgKOH / g) is used in c parts by mass, the average acid value (mgKOH / g) of the polyolefin (B) can be calculated as (xb + yc) / (a + b + c).

In the above resin composition, the mass ratio (B1 / B) of the unmodified polyolefin (B1) to the polyolefin (B) is preferably 0.75 or more and less than 1.00. When the mass ratio (B1 / B) is 0.75 or more, an excessive increase in viscosity is suppressed, good moldability is more reliably maintained especially in a high temperature environment, and the domain diameter of the discontinuous phase is increased. It can be kept moderate and the deterioration of impact resistance can be suppressed more effectively. On the other hand, the mass ratio (B1 / B) is more preferably 0.95 or less from the viewpoint of suppressing excessive coarsening of the domain diameter of the discontinuous phase and, by extension, effectively improving the impact resistance. It is more preferably 0.92 or less.

Further, in the above resin composition, the mass ratio (A / B) of the polyamide resin (A) to the polyolefin (B) is preferably 1.0 or more. When the mass ratio (A / B) is 1.0 or more, a predetermined sea-island structure can be formed more reliably. From the same viewpoint and from the viewpoint of appropriately reducing the domain diameter of the discontinuous phase, the mass ratio (A / B) is more preferably 1.0 or more, and further preferably 1.2 or more. , 1.5 or more is more preferable.
Further, in the above resin composition, the mass ratio (A / B) of the polyamide resin (A) to the polyolefin (B) is preferably 4.0 or less. When the mass ratio (A / B) is 4.0 or less, the domain diameter of the discontinuous phase can be appropriately increased. From the same viewpoint, the mass ratio (A / B) is more preferably 3.0 or less, further preferably 2.5 or less, and even more preferably 2.0 or less.

(Other ingredients)
In addition to the above-mentioned resin compositions, the above resin compositions include various additives that are usually blended, such as flow improvers, compatibilizers, cross-linking additives, organic solvents, polymerization initiators, and polymerization inhibitors, as long as they do not impair the purpose. , Chain transfer agent, light stabilizer, crystal nucleating agent / mold release agent, lubricant, antioxidant, flame retardant, light resistant agent, weather resistant agent and the like can be contained in an appropriate amount depending on the purpose.

The method for preparing the resin composition is not particularly limited, and for example, the resin composition of the present embodiment can be obtained by blending and kneading the above-mentioned components according to a conventional method. In addition, at the time of blending and kneading, all the components may be blended and kneaded at one time, or each component may be blended and kneaded in multiple stages such as two steps or three steps. For kneading, a kneading machine such as a roll, an internal mixer, or a Banbury rotor can be used.

(Carbon fiber)
The complex of this embodiment contains carbon fibers. As a result, high rigidity can be obtained while being lightweight. Carbon fibers can include continuous fibers and / or discontinuous fibers. In the present specification, the continuous fiber refers to a fiber having a length of 5 cm or more, and includes not only a single fiber but also a fiber sewn into a sheet shape. Further, in the present specification, the discontinuous fiber refers to a reinforcing fiber other than the continuous fiber.

The carbon fiber is preferably selected from the group consisting of continuous fiber and long fiber of 0.05 cm or more, and continuous fiber is more preferable. Further, the fiber length of the carbon fiber is more preferably 1 cm or more. The carbon fiber is most preferably a continuous fiber from the viewpoint of impact resistance. The shorter the length of the carbon fiber, the smaller the effect of improving the impact resistance, but on the other hand, there is an advantage that it can be applied to a wider range of molding methods.

The composite of the present embodiment may contain other fibers other than carbon fibers. Such other fibers include, for example, glass fiber, glass milled fiber, potassium titanate whisker, zinc oxide whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, stone fiber, metal fiber. , Organic fiber and the like.

The method for producing the composite of the present embodiment is not particularly limited, but the composite of the present embodiment can be suitably produced by the method for producing a carbon fiber composite described later.

<Manufacturing method of carbon fiber composite>
The method for producing a carbon fiber composite according to an embodiment of the present invention (hereinafter, may be referred to as "the production method for the present embodiment") is a carbon fiber containing carbon fibers and a matrix portion composed of a resin composition. It is a method for manufacturing a complex.
A sheet forming step of forming a sheet having a thickness of 10 μm or more and 500 μm or less from the resin composition containing the polyamide resin (A) and the polyolefin (B).
A composite acquisition step of contacting the sheet with the carbon fibers to obtain a carbon fiber composite containing the carbon fibers and a matrix portion made of the resin composition is provided.
The polyamide resin (A) contains only a semi-aromatic polyamide resin (A1), and the polyolefin (B) contains an unmodified polyolefin (B1) and a modified polyolefin (B2).
According to the manufacturing method of the present embodiment, it is possible to manufacture a carbon fiber composite having high impact resistance and excellent moldability.

The manufacturing method of the present embodiment may appropriately include steps other than the above-mentioned steps (for example, a cross-linking step described later).

(Sheet forming process)
In the sheet forming step, a sheet having a thickness of 10 μm or more and 500 μm or less is formed from the resin composition containing the polyamide resin (A) and the polyolefin (B). The polyamide resin (A) contains only a semi-aromatic polyamide resin (A1), and the polyolefin (B) contains an unmodified polyolefin (B1) and a modified polyolefin (B2). Then, in this sheet forming step, a sheet having a sea-island structure can be formed by the continuous phase of the polyamide resin (A) (semi-aromatic polyamide resin (A1)) and the discontinuous phase of the polyolefin (B).

The sheet forming step is not particularly limited, and it is preferable to form a predetermined sea-island structure by appropriately selecting the contents described above for the complex of the present embodiment.

The resin composition used in the sheet forming step includes components other than the semi-aromatic polyamide resin (A1) and the polyolefin (B), for example, a flow improver, a compatibilizer, a cross-linking additive, an organic solvent, and polymerization initiation. Agents, polymerization inhibitors, chain transfer agents, light stabilizers, crystal nucleating agents / mold release agents, lubricants, antioxidants, flame retardants, light resistant agents, weather resistant agents and the like can be appropriately blended according to the purpose.

The resin composition used in the sheet forming step conforms to JIS K 7199 and has a viscosity (300 ° C. viscosity) measured at a temperature of 300 ° C. and a shear rate of 12.16s ^-1 at 900 Pa · s or more and 4000 Pa · s or less. It is preferable to have. The reason for this is as described above. The sheet forming step is not particularly limited, and it is preferable to adjust the viscosity at 300 ° C. by appropriately selecting the contents described above for the complex of the present embodiment.

The thickness of the sheet formed in the sheet forming step is 10 μm or more and 500 μm or less. Since the above-mentioned resin composition is used as a raw material in the sheet forming step, it can be produced with a predetermined thinness (500 μm or less) with high moldability.

In the sheet forming step, for example, the above-mentioned resin composition can be melted and molded into a sheet by extrusion molding (melt extrusion molding). In melt extrusion molding, for example, the above-mentioned resin composition is heated and melted and supplied to a die such as a T-die through a gear pump or a filter. Next, the melt supplied to the die is extruded into a sheet and appropriately cooled and solidified using a cooling roll or the like to obtain a sheet.

(Complex acquisition process)
In the composite acquisition step, the sheet formed in the sheet forming step and the carbon fiber are brought into contact with each other to obtain a carbon fiber composite containing the carbon fiber and the matrix portion made of the resin composition. The carbon fibers are as described above.

The form in which the sheet and the carbon fiber are brought into contact with each other is not particularly limited as long as the sheet and the carbon fiber are in direct contact with each other, and examples thereof include the following (a) to (e).
(A) A form in which a sheet and carbon fiber are directly or indirectly bonded to each other.
(B) A method in which carbon fibers are directly or indirectly sandwiched between a pair of sheets, or a form in which sheets are directly or indirectly sandwiched between a pair of carbon fibers.
(C) A form in which a plurality of sheets and carbon fibers are (alternately) laminated.
(D) A form in which the sheet is heated at a temperature equal to or higher than the melting point of the semi-aromatic polyamide resin (A1) contained in the sheet, and then the molten sheet is impregnated with carbon fibers.
(E) A form in which a sheet and carbon fibers are bonded (or placed in contact with each other) and then heated to a temperature equal to or higher than the melting point of the semi-aromatic polyamide resin (A1) to be impregnated with the carbon fibers.

In the complex acquisition step, if necessary, a metal mold such as a male mold or a female mold may be used, or the above sheet and carbon fiber may be brought into contact with each other in the mold. Therefore, any of the above (a) to (e) may be performed in the mold. Further, in the above (a) to (e), when the sheet and the carbon fiber are bonded, sandwiched, or laminated, a known binder, a semi-aromatic polyamide resin (A1), or a polyolefin (A1) may be used, if necessary. A solution in which B) is dissolved in an organic solvent may be used as a binder.

The orientation direction of the carbon fibers with respect to the sheet is not particularly limited. Further, the number of sheets and the number of carbon fibers when the sheets and carbon fibers are brought into contact with each other are not particularly limited and can be appropriately selected.

The conditions for contacting the sheet with the carbon fiber are not particularly limited, and conditions such as the sheet temperature, atmosphere, and contact pressure can be appropriately set according to the contact mode.

(Crosslinking process)
In the production method of the present embodiment, it is preferable that the cross-linking step of cross-linking the polyolefin (B) is further provided between the start of the sheet forming step and the completion of the complex acquisition step. By cross-linking the polyolefin (B), the impact resistance of the obtained complex can be further improved. The cross-linking step can be performed at any time from the start of the sheet forming step to the completion of the complex acquisition step.

The cross-linking in the above-mentioned cross-linking step is preferably one or more selected from the group consisting of electron beam cross-linking, chemical cross-linking, electromagnetic cross-linking, and thermal cross-linking.

Electron beam cross-linking can be performed by a known method. When the polyolefin (B) is irradiated with an electron beam, a part of the polymer chain constituting the polyolefin (B) is cleaved to generate radicals. Then, the radical is recombined with other sites of the polymer chain to form a crosslinked structure. The electron beam used for such electron beam cross-linking is composed of electrons having a predetermined energy emitted from an electron gun or the like. Electron guns that are electron sources include thermal electron guns, field emission electron guns, and shotkey electron guns. As long as electron beam cross-linking is possible, the type, strength, electron source, etc. of the electron beam do not matter. The

The absorbed dose in the irradiation of the electron beam is preferably 20 to 600 kGy, more preferably 50 to 500 kGy. If the absorbed dose is 600 kGy or less, the polymer chain of the polyolefin (B) is cut without cutting the polymer chain of the semi-aromatic polyamide resin (A1), and if the absorbed dose is 20 kGy or more, the polyolefin is cut. It becomes easy to cut the polymer chain of (B). Further, by setting the absorbed dose of the electron beam within the above range, the cross-linking rate or the molecular weight can be adjusted within an appropriate range, and it is possible to easily suppress or prevent the shape change of the discontinuous phase.

When the electron beam is irradiated in an oxygen atmosphere, the generated radicals may be inactivated, so it is preferable to perform the electron beam irradiation in an inert gas atmosphere such as nitrogen or argon.

It should be noted that it is possible to confirm whether or not the polyolefin (B) is crosslinked when irradiated with an electron beam, for example, by measuring the change in the viscosity of the polyolefin (B), or by GPC ( It can be performed using gel permeation chromatography).

The chemical cross-linking is not particularly limited and can be carried out by a known method. The chemical cross-linking is preferably a method of carrying out a cross-linking reaction by light irradiation or heating in the presence of a chemical cross-linking agent, or a silane cross-linking method. In the silane cross-linking method, cross-linking due to silanol bonds is formed between the molecular chains of the polyolefin (B) by contacting with water in the presence of a catalyst such as a coupling agent, a radical initiator and an organic tin compound. ..

For example, chemical cross-linking is preferably carried out using a chemical cross-linking agent and a cross-linking aid, an activator or a catalyst compounded as necessary. Examples of the chemical cross-linking agent include a phenol resin such as alkylphenol formaldehyde, and a silane coupling agent such as vinylalkoxysilane such as vinyltrimethoxysilane or vinyltriethoxysilane. Examples of the cross-linking aid include sulfur, p-dinitrosobenzene, divinylbenzene, 1,3-diphenylguanidine, stannous chloride / anhydrous, stannous chloride / dihydrate, and second chloride. Examples include iron. Examples of the activator include halogen donors such as chlorinated paraffin, chlorinated polyethylene, and chlorosulphonized polyethylene, iron oxide, titanium oxide, magnesium oxide, silicon dioxide, zinc oxide, and radical initiators. Can be mentioned. Examples of the radical initiator include organic peroxides such as dicumyl peroxide. Further, examples of the catalyst include organic tin compounds such as dibutyl tin laurate.

The electromagnetic wave cross-linking is not particularly limited and can be performed by a known method. As the electromagnetic wave used for electromagnetic wave bridging, ionizing radiation such as ultraviolet rays, visible rays, α rays, β rays, γ rays, proton rays, heavy ion rays, and neutron rays can be used. Among these, as the electromagnetic wave, ultraviolet rays are preferable from the viewpoint of deterioration of the sheet. In electromagnetic wave cross-linking, it is preferable to cross-link the polyolefin (B) by irradiating the electromagnetic wave in the presence of an electromagnetic wave initiator. For example, electromagnetic wave cross-linking uses an electromagnetic wave initiator (for example, an ultraviolet wave initiator), an electromagnetic wave cross-linking agent (for example, an ultraviolet wave cross-linking agent), and an electromagnetic wave absorber compounded as necessary (for example, an ultraviolet wave absorber). It is preferable to do it. Examples of the electromagnetic wave cross-linking agent include ultraviolet cross-linking agents such as benzophenones and melamine compounds. Examples of the electromagnetic wave initiator include benzoin-based photoinitiators. Examples of the electromagnetic wave absorber include triazine-based ultraviolet absorbers (TINUVIN series) and hindered amine-based ultraviolet absorbers (HALS).

The light source of the above ultraviolet rays is not particularly limited, and can be appropriately set in consideration of the wavelength to be irradiated (for example, in the range of 200 to 450 nm). For example, a light source such as a high-pressure mercury lamp, a low-pressure mercury lamp, a xenon lamp, a mercury xenon lamp, a metal halide lamp, or an ultraviolet laser light source can be mentioned. Further, when irradiating with ultraviolet rays, light of a specific wavelength may be irradiated by using a wavelength filter, if necessary.

Thermal cross-linking is not particularly limited and can be performed by a known method. In thermal cross-linking, it is preferable to cross-link the polyolefin (B) by performing a heat treatment in the presence of a thermal cross-linking agent. Examples of the thermal cross-linking agent include organic peroxides such as hydroperoxides, oxime compounds, and azo compounds such as triallyl cyanurate or triallyl isocyanurate. The

The above-mentioned chemical cross-linking agent, cross-linking aid, activator, catalyst, electromagnetic wave initiator, electromagnetic wave cross-linking agent, electromagnetic wave absorber and thermal cross-linking agent are collectively referred to as "cross-linking additive" in the present specification.

In the production method of the present embodiment, the timing of performing the crosslinking step is not particularly limited as long as it is between the start of the sheet forming step, that is, immediately after the start of the sheet forming step and the completion of the complex acquisition step. .. In addition, "performing the crosslinking step from the start of the sheet forming step" means that the semi-aromatic polyamide resin (A1) and the polyolefin (B) (for example, at least the semi-aromatic polyamide resin (A1) and the polyolefin (B) are mixed. In the sheet forming step of forming a sheet of the obtained resin composition, etc.), it means that the polyolefin (B) in the discontinuous phase is crosslinked immediately after the discontinuous phase of the polyolefin (B) is formed. Further, the cross-linking step may be performed in parallel with each of the other steps, or may be performed after each step. Further, "performing a cross-linking step until the completion of the complex acquisition step" literally means cross-linking the polyolefin (B) until the complex acquisition step is completely completed. Therefore, in the form of performing the cross-linking step in the composite acquisition step (for example, when the molding of the sheet and the carbon fiber and the cross-linking step of the polyolefin (B) are performed in combination), and the molding of the sheet and the carbon fiber are performed. Any of the forms performed a plurality of times (for example, when a plurality of carbon fiber composites are laminated) is applicable. By cross-linking the polyolefin (B) constituting the discontinuous phase in the sheet before applying an external stimulus such as heat to the sheet, the shape of the discontinuous phase can be more easily maintained until the final product.

The cross-linking step is preferably performed during the sheet forming step, the composite acquisition step, or between the sheet forming step and the carbon fiber composite acquisition step.

By cross-linking the polyolefin (B) constituting the discontinuous phase before molding the sheet and carbon fibers, that is, before applying an external stimulus such as heat to the sheet, the shape of the discontinuous phase is further maintained. It will be easier. Further, if the cross-linking step is performed during any of the above steps, the manufacturing efficiency is improved.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

(Preparation of resin composition)
Using a capillograph (manufactured by Toyo Seiki Seisakusho Co., Ltd., "Capillograph 1D"), the resin composition having the formulation shown in Table 1 is based on JIS K 7199 and has a viscosity at a temperature of 300 ° C. and a shear rate of 12.16s ^-1 . 300 ° C. viscosity) was measured. The results are shown in Table 1.

In addition, the appearance of the surface of the strand made of the resin composition obtained at the time of viscosity measurement was visually evaluated according to the following criteria. The results are shown in Table 1. The evaluation result is an index of moldability. Further, usually, when the appearance of the strand is poor, the sheet formability tends to be poor.
A: The entire surface is smooth.
B: Infrequent roughness is observed on the surface.
C: Roughness or unevenness is observed on the entire surface.

Further, after smoothing the above resin composition using a microtome, an image of 30 μm × 30 μm was acquired by an atomic force microscope (AFM) (manufactured by Shimadzu Corporation, “SPM-9700HT”), and Kaijima. The presence or absence of the structure (continuous phase and discontinuous phase) was confirmed. The results are shown in Table 1. Furthermore, in the example in which the sea-island structure was confirmed, the average value of the circle-equivalent diameter (diameter of a circle of the same area) was calculated for all the discontinuous phases (domains) observed from the above image, and the domain diameter was obtained. rice field. The results are shown in Table 1.

For the resin composition of Comparative Example 1-5, an attempt was made to form a sheet by using a T-die sheet forming apparatus. However, in Comparative Example 1, a large thickening phenomenon occurred during molding, and a large number of resin lumps and holes were generated, so that the sheet could not be molded. Further, in Comparative Example 5, the polyolefin was formed as a continuous phase, the resin was easily pulsated during sheet molding, and a sheet having a predetermined thickness could not be molded.
On the other hand, for the resin compositions of Examples 4, 5 and 11 and Comparative Example 6, a sheet having a thickness of 60 μm was molded by a T-die sheet molding apparatus. Next, unidirectional open fibers (carbon fiber, continuous fiber) are placed above and below this sheet, and a composite prepreg is hot-pressed under the conditions of a temperature of 280 ° C. and a pressure of 1 MPa using a press machine (manufactured by Kodaira Seisakusho Co., Ltd.). (Carbon fiber composite) was prepared. Twenty layers of this composite prepreg were alternately laminated in the 0 ° and 90 ° directions and hot-pressed under the conditions of a temperature of 300 ° C. and a pressure of 5 MPa to obtain a laminate having a size of 160 mm × 160 mm and a thickness of 2.0 mm. Using this laminate, the shock absorption energy was measured according to ISO6603-2: 2000. The results are shown in Table 1. If the impact absorption energy is 60.0 J or more, it can be considered that the impact resistance is good.

* 1 Semi-aromatic polyamide resin: manufactured by Kuraray Co., Ltd., polyamide 9T, melting point: 265 ° C.
* 2 Unmodified polyolefin: "DF640" manufactured by Mitsui Chemicals, Inc., acid value: 0 mgKOH / g
* 3 Modified polyolefin 1 ... "MH7020" manufactured by Mitsui Chemicals, Inc., acid value: 11 mgKOH / g
* 4 Modified polyolefin 2 ... "MH7010" manufactured by Mitsui Chemicals, Inc., acid value: 5.5 mgKOH / g
* 5 Antioxidant: "IRGANOX1098" manufactured by BASF

From Table 1, it can be seen that in the examples, the appearance of the strands made of the resin composition is good and the viscosity is appropriate at 300 ° C., so that the moldability is excellent. Further, in the examples, since the resin composition contains a semi-aromatic polyamide resin and a discontinuous phase (polyolefin domain) having an appropriate size is dispersed and formed, it exhibits high impact resistance. You can also see that it can be done.

According to the present invention, it is possible to provide a carbon fiber composite having high impact resistance and excellent moldability while using a semi-aromatic polyamide resin.
Further, according to the present invention, it is possible to provide a method for producing a carbon fiber composite having high impact resistance and excellent moldability while using a semi-aromatic polyamide resin.

Claims (6)

1. A carbon fiber composite containing carbon fibers and a matrix portion composed of a resin composition.
   The resin composition has a sea-island structure consisting of a continuous phase of the polyamide resin (A) and a discontinuous phase of the polyolefin (B).
   The polyamide resin (A) contains only the semi-aromatic polyamide resin (A1), and contains only the semi-aromatic polyamide resin (A1).
   The polyolefin (B) contains an unmodified polyolefin (B1) and a modified polyolefin (B2).
   The carbon fiber composite is characterized in that the resin composition conforms to JIS K 7199 and has a viscosity measured at a temperature of 300 ° C. and a shear rate of 12.16s ^-1 of 900 Pa · s or more and 4000 Pa · s or less. body.
2. The carbon fiber composite according to claim 1, wherein the semi-aromatic polyamide resin (A1) has a melting point of 280 ° C. or lower.
3. The carbon fiber composite according to claim 1 or 2, wherein in the resin composition, the mass ratio of the polyamide resin (A) to the polyolefin (B) is 1.0 or more and 4.0 or less.
4. The carbon fiber composite according to any one of claims 1 to 3, wherein in the resin composition, the mass ratio of the unmodified polyolefin (B1) to the polyolefin (B) is 0.75 or more and less than 1.00. body.
5. A method for producing a carbon fiber composite containing carbon fibers and a matrix portion composed of a resin composition.
   A sheet forming step of forming a sheet having a thickness of 10 μm or more and 500 μm or less from the resin composition containing the polyamide resin (A) and the polyolefin (B).
   A composite acquisition step of contacting the sheet with the carbon fibers to obtain a carbon fiber composite containing the carbon fibers and a matrix portion made of the resin composition is provided.
   The polyamide resin (A) contains only a semi-aromatic polyamide resin (A1), and the polyolefin (B) contains an unmodified polyolefin (B1) and a modified polyolefin (B2). Method for producing the complex.
6. The method for producing a carbon fiber composite according to claim 5, further comprising a cross-linking step for cross-linking the polyolefin (B) between the start of the sheet forming step and the completion of the composite acquisition step.