JP5821052B2 - Composite material laminate - Google Patents

Description

  The present invention relates to a composite material laminate using a carbon fiber reinforced resin.

In recent years, the field of use of molded articles composed of composite materials made of carbon fiber reinforced resin has been expanded, and for example, it has begun to be used in cars and aircrafts. The molded article is produced by laminating a plurality of sheet-like prepregs in which carbon fibers are impregnated with a curable resin and curing. At that time, when a prepreg with reinforcing fibers oriented in one direction is used as the prepreg, and when multiple sheets are laminated so that the arrangement pattern of the reinforcing fibers after lamination is symmetric, the tensile elongation is almost isotropic A pseudo-isotropic laminate is obtained.
For example, as a pseudo-isotropic laminate, the reinforcing fiber orientation direction is oriented at 90 ° with the layer oriented at 0 ° (“0 °” means parallel to the reference direction for convenience). A two-layer stack with the above-mentioned layers, a three-layer stack with a layer oriented with a fiber orientation direction of 0 °, a layer oriented with 90 ° and a layer oriented with 0 °, and a layer with a fiber orientation direction oriented at 45 ° and 0 A four-layer laminate of a layer oriented at 0 °, a layer oriented at −45 °, and a layer oriented at 90 ° is known.

By the way, high tensile properties are required for materials used for aircraft and the like. Then, although the method of using the carbon fiber which has a high tensile characteristic about 2.0% of tensile elongation is considered, even when using such a carbon fiber, it is 0 degree direction of the conventional pseudo-isotropic laminated board. The tensile elongation was not high enough. Strictly speaking, the conventional pseudo-isotropic laminate has a lower tensile elongation in the direction of ± 45 ° and 90 ° than in the 0 ° direction, and when the tensile properties are measured in the 0 ° direction due to the influence thereof. This is because fracture occurs first in a direction other than 0 °.
Therefore, Patent Document 1 and Non-Patent Document 1 propose that the layer containing carbon fibers oriented at 90 ° or ± 45 ° is thinned to improve the tensile properties of the pseudo-isotropic laminate.

Special table 2008-514458 gazette

Hideki Hatakeyama et al., “Effect of Layer Thickness on Initial Failure of Multidirectional Reinforced Composite Laminates”, Journal of the Japan Society for Composite Materials, 2004, Vol. 30, No. 4, p. 142-148

However, even with the methods described in Patent Document 1 and Non-Patent Document 1, the tensile elongation of the composite laminate is not sufficiently high, and it is difficult to satisfy the above requirements.
This invention is made | formed in view of the said situation, and it aims at providing the composite material laminated board with a large tensile elongation.

[1] A carbon fiber oriented at 0 ° with respect to the reference direction and a 0 ° orientation layer containing a resin, a carbon fiber oriented in a direction other than 0 °, and a thickness of 0.044 mm or less containing a resin Including one or more other orientation layers,
The carbon fibers contained in the 0 ° orientation layer and the other-direction orientation layer have a maximum height difference of 10 to 45 nm, an average roughness of 3 to 7 nm, and a ratio of the major axis to the minor axis of the cross section of the single fiber. A composite laminate having a fiber bundle of 1.00 to 1.01 and a tensile elongation of 2.2% or more.
[2] The composite material laminate according to [1], wherein the other direction orientation layer is one layer or two layers, and is a 90 ° orientation layer in which carbon fibers are oriented at about 90 ° with respect to the reference direction.
[3] The other direction orientation layers are three layers, a 90 ° orientation layer in which carbon fibers are oriented at approximately 90 ° with respect to the reference direction, and a 45 ° orientation layer in which the carbon fibers are oriented at approximately 45 ° with respect to the reference direction. The composite material laminate according to [1], wherein the carbon fiber is a −45 ° orientation layer in which the carbon fibers are oriented at approximately −45 ° with respect to the reference direction.

  The composite laminate of the present invention has a high tensile elongation and is 2.1% or more in the 0 ° direction.

It is sectional drawing which shows one embodiment of the composite material laminated board of this invention.

An embodiment of the composite material laminate of the present invention will be described.
As shown in FIG. 1, the composite material laminate 1 of this embodiment example is a rectangular shape including a 45 ° orientation layer 10, a 0 ° orientation layer 20, a −45 ° orientation layer 30, and a 90 ° orientation layer. The four-layer laminate. Here, “0 °” means that it is parallel to a reference direction (hereinafter referred to as “reference direction”) for convenience, and “45 °”, “−45 °”, “90 °”. "Means 45 °, -45 ° (135 °) and 90 °, respectively, with respect to the reference direction. In the present embodiment, the longitudinal direction of the composite material laminate is parallel to the reference direction.

The 45 ° orientation layer 10 contains a carbon fiber oriented approximately 45 ° with respect to the reference direction and a resin.
The thickness of the 45 ° orientation layer 10 is 0.044 mm or less, and preferably 0.03 mm or less. When the thickness of the 45 ° orientation layer 10 is 0.04 mm or less, the tensile elongation of the composite laminate 1 can be improved.
Moreover, it is preferable that the thickness of the 45 degree orientation layer 10 is 0.01 mm or more from the point on manufacture.

It contains 0 ° orientation layer 20, carbon fibers oriented in the reference direction, and resin.
The thickness of the 0 ° orientation layer 20 is preferably 0.01 mm or more and 0.10 mm or less, and more preferably 0.01 to 0.08 mm. If the thickness of the 0 ° orientation layer 20 is 0.01 mm or more, the number of laminated prepreg materials can be reduced when producing a laminate having a predetermined thickness. If it is 0.10 mm or less, the orientation layers other than the 0 ° direction can be increased, and the balance of the mechanical performance of the laminate other than the 0 ° direction can be maintained.

-45 degree orientation layer 30, The carbon fiber orientated at about -45 degree with respect to the reference direction, and resin are contained.
The thickness of the −45 ° alignment layer 30 is 0.044 mm or less and preferably 0.03 mm or less for the same reason as that of the 45 ° alignment layer 10. Moreover, it is preferable that the thickness of the -45 degree orientation layer 30 is 0.01 mm or more.

The 90 ° orientation layer 40 contains carbon fibers oriented approximately 90 ° with respect to the reference direction and a resin.
The thickness of the 90 ° orientation layer 40 is 0.044 mm or less and preferably 0.03 mm or less for the same reason as that of the 45 ° orientation layer 10. The thickness of the 90 ° orientation layer 40 is preferably 0.01 mm or more.

As the resin used in the 45 ° oriented layer 10, the 0 ° oriented layer 20, the −45 ° oriented layer 30 and the 90 ° oriented layer 40, a cured product of a thermosetting resin or a thermoplastic resin is used. Examples of the thermosetting resin include an epoxy resin, an unsaturated polyester resin, an acrylic resin, a vinyl ester resin, a phenol resin, and a benzoxazine resin. Among these, an epoxy resin is preferable because of its high strength and high interfacial adhesiveness with carbon fibers. More preferably, the bending strength in the 90 ° direction of the unidirectional composite material laminate according to ASTM D790 is 100 MPa or more. More preferably, it is 110 MPa or more. This is because if the 90 ° bending strength is high, breakage of the laminated portion other than the 0 ° direction in the composite material laminated plate is suppressed.
In addition, each layer 10, 20, 30, 40 may contain various additives such as a curing agent, a release agent, a defoaming agent, an ultraviolet absorber, and a filler.

In the 45 ° oriented layer 10, the 0 ° oriented layer 20, the −45 ° oriented layer 30 and the 90 ° oriented layer 40, the following carbon fibers are used.
That is, the carbon fiber used for each layer 10, 20, 30, 40 is a fiber bundle composed of a large number of single fibers. The side surface of the single fiber constituting the carbon fiber used in the present invention is substantially smooth, but microscopically has irregularities. Specifically, the maximum height difference on the surface of the single fiber is 10 to 45 nm, and the average unevenness is 3 to 7 nm. Here, the maximum height difference and the average unevenness are values obtained by measuring the surface of a single fiber using a scanning atomic force microscope.
Moreover, in the carbon fiber used in the present invention, the cross section perpendicular to the longitudinal direction of the single fiber is almost a perfect circle. Specifically, the ratio of the major axis to the minor axis of the cross section of the single fiber is 1. It is 00-1.01, and it is preferable that it is 1.00-1.005. By being close to a perfect circle, since the structural uniformity in the vicinity of the fiber surface is excellent, stress concentration can be reduced, and the tensile elongation of the composite laminate 1 is increased. The ratio of the major axis to the minor axis is measured by observing the cross section of the short fiber with a scanning electron microscope. Here, the “major axis” is the longest diameter in the cross section of the carbon fiber, and the “minor axis” is the shortest diameter in the cross section of the carbon fiber.

As described above, the ratio of the major axis to the minor axis of the cross section of the single fiber is 1.00 to 1.01, the maximum height difference on the surface of the single fiber is 45 nm or less, and the average unevenness is 7 nm or less. As a result, the stress concentration portion is reduced, and the interface breakage when the composite material is formed is suppressed, so that the tensile elongation of the composite material laminate 1 is increased.
Further, the ratio of the major axis to the minor axis of the cross section of the single fiber is 1.00 to 1.01, the maximum height difference of the surface of the single fiber is 10 nm or more, and the average unevenness is 3 nm or more, Since the interfacial adhesiveness with the resin is increased, the tensile properties when the composite material is obtained are improved.

Moreover, since the tensile elongation can be further increased, the mass range per unit length of the single fiber is preferably 0.030 to 0.042 mg / m.
In addition, since the strength of the carbon fiber becomes higher, the fracture surface generation energy required by the following method is preferably 30 N / m or more, more preferably 31 N / m or more, and 32 N / m or more. More preferably it is.
[How to determine fracture surface generation energy]
By forming a hemispherical defect having a size within a predetermined range with a laser on the surface of the single fiber, the carbon fiber is broken at the hemispherical defect site by a tensile test, and based on the breaking strength of the carbon fiber and the size of the hemispherical defect, The fracture surface generation energy is obtained from the following Griffith equation.
σ = √ (2E / πC) × √ (Fracture surface generation energy)
Here, σ is the breaking strength, E is the ultrasonic elastic modulus of the carbon fiber bundle, and c is the size of the hemispherical defect.

The tensile elongation of the carbon fiber is 2.2% or more, and preferably 2.3% or more. Here, the tensile elongation is a value obtained by measuring the tensile breaking strength and the tensile elastic modulus according to the A method according to JIS R7608, and by the calculation method described in 10.3.3 of JIS R7608. When the tensile elongation of the carbon fiber is 2.2% or more, the tensile elongation of the composite laminate 1 is increased.
The tensile strength of the carbon fiber is preferably 5900 MPa or more, more preferably 6000 MPa or more, and further preferably 6100 MPa or more. Here, the tensile strength is a value measured according to JIS R7609. When the tensile strength is 5900 MPa or more, the tensile elongation of the composite laminate 1 becomes higher.
The tensile elastic modulus of the carbon fiber is preferably 245 to 350 GPa, and more preferably 250 to 330 GPa. Here, the tensile modulus is a value measured according to JIS R7609. When the tensile elastic modulus is 245 GPa or more, the tensile elastic modulus of the composite laminate 1 becomes a sufficient level, and a laminate having excellent mechanical performance can be obtained. If it is 350 GPa or less, the compressive strength of the carbon fiber in the fiber axis direction can be maintained at a strength level equivalent to the tensile strength, and deterioration of the mechanical performance of the laminate can be avoided.

In order to produce the above carbon fiber, the following precursor fiber and processing conditions may be applied in the method for producing carbon fiber to be carbonized after flame resistance of the precursor fiber.
In this production method, acrylonitrile polymer-based precursor fiber obtained by using 96% by mass or more, preferably 97% by mass or more of acrylonitrile and several kinds of copolymerizable monomers is used as the precursor fiber. Examples of copolymer components other than acrylonitrile include acrylic acid derivatives such as acrylic acid, methacrylic acid, itaconic acid, methyl acrylate, methyl methacrylate, acrylamide, methacrylamide, N-methylol acrylamide, N, N-dimethylacrylamide, and the like. Acrylamide derivatives, vinyl acetate and the like. These may be used individually by 1 type and may use 2 or more types together.
A preferred copolymer includes an acrylonitrile polymer obtained by copolymerizing a monomer having one or more carboxyl groups (acrylic acid, methacrylic acid, itaconic acid, etc.) with acrylonitrile.
Preferably, an acrylonitrile copolymer obtained by copolymerizing 0.3% by mass or more and 4.0% by mass or less of a monomer having one or more carboxyl groups with 96.0% by mass or more and 99.7% by mass or less of acrylonitrile. A polymer is used. A more preferable acrylonitrile content is 98.0% by mass or more.

The precursor fiber is obtained by discharging a spinning stock solution obtained by dissolving the acrylonitrile-based polymer in an organic solvent into the air once from a spinneret, and then discharging and coagulating the temperature-controlled coagulating liquid.
Examples of the organic solvent include dimethylacetamide, dimethylsulfoxide, dimethylformamide, and the like.
The solid concentration of the spinning dope is preferably 20% by mass or more, and more preferably 21% by mass or more. The higher the solid content concentration, the easier it is to produce a solidified yarn having a dense structure.

The coagulated yarn obtained by coagulation of the spinning dope is subjected to drawing treatment and washing treatment.
The temperature of the stretching tank for performing the stretching treatment is preferably in the range of 40 to 80 ° C, more preferably 50 to 75 ° C. If the temperature of the stretching tank is less than 40 ° C., sufficient stretchability cannot be ensured and a uniform fibril structure may not be formed. On the other hand, when the temperature exceeds 80 ° C., the plasticizing action due to heat becomes too large, and solvent removal on the surface of the yarn rapidly proceeds and the stretching becomes non-uniform, so that the quality of the precursor fiber bundle tends to deteriorate. .
Moreover, 30-60 mass% is preferable and, as for the density | concentration of the said organic solvent of an extending | stretching tank, it is more preferable that it is 35-55 mass%. If the concentration of the organic solvent in the stretching tank is less than 30% by mass, it may not be possible to stretch stably, and if it exceeds 60% by mass, the plasticizing effect may be too great and it may not be possible to stretch stably.
The stretching ratio in the stretching tank is preferably 2 to 4 times, more preferably 2.2 to 3.8 times, and even more preferably 2.5 to 3.5 times. If the draw ratio is less than 2.2 times, the drawing may be insufficiently stretched and a desired fibril structure may not be formed. On the other hand, if the stretching exceeds 3.8 times, the fibril structure itself may be broken, resulting in a precursor fiber bundle having a sparse structure.
The cleaning treatment is not particularly limited as long as it can remove the solvent, and examples thereof include a method of immersing in a tank filled with a cleaning solution, and a method of spraying the cleaning solution at a high pressure.

  Moreover, the fiber orientation can be further enhanced by stretching a fiber bundle in a swollen state free from solvent after washing in hot water. In addition, when relaxed, stretching distortion can be removed. The stretching ratio when stretching in hot water is preferably 0.98 to 2.0 times. When the draw ratio exceeds 2.0 times, structural breakage due to unreasonable drawing occurs, which may cause defect point formation in the firing step.

After the stretching and washing treatments, an adhesion treatment for attaching 0.8 to 1.6% by mass of an oil agent containing a silicone compound as a main component is performed to dry and densify. Dry densification may be performed by drying and densification by a known drying method, and among them, a method of passing a plurality of heating rolls is preferable.
After drying and densification, if necessary, the film is stretched by 1.8 to 6.0 times in a pressurized steam or dry heat medium at 130 to 200 ° C. or between heating rolls or on a heating plate, and further oriented. Improvement and densification may be performed. A method using pressurized steam is preferable because it can be stably stretched by plasticization with steam.

In flameproofing, for example, the precursor fiber bundle obtained as described above is passed through a hot air circulation type flameproofing furnace at 220 to 260 ° C. to obtain flameproofed yarn.
The flameproofing reaction includes a cyclization reaction by heat and an oxidation reaction by oxygen, and it is important to balance these two reactions. In order to balance these two reactions, the flameproofing treatment time is preferably 30 to 100 minutes, and more preferably 40 to 80 minutes. When the flameproofing treatment time is less than 30 minutes, a portion where the oxidation reaction has not sufficiently occurred exists on the inside of the single fiber, and a large structural spot may occur in the cross-sectional direction of the single fiber. As a result, the obtained carbon fiber has a non-uniform structure, and thus high tensile properties may not be obtained. On the other hand, when the flameproofing treatment time exceeds 100 minutes, a large amount of oxygen is present in the vicinity of the surface of the single fiber, and a reaction in which excess oxygen disappears due to the subsequent heat treatment at a high temperature occurs to form defect points. There are things to do.

Preferably the density of the flame-resistant yarn is 1.335~1.360g / cm ^3, more preferably 1.340~1.350g / cm ^3. If the density of the flame-resistant yarn is less than 1.335 g / cm ³ , flame resistance is insufficient, and a subsequent heat treatment at a high temperature causes a decomposition reaction, so that the strength does not increase to form defect points. is there. When the flameproof yarn density exceeds 1.360 g / cm ³ , the oxygen content of the fiber is large, so that a reaction in which excess oxygen disappears by heat treatment at a subsequent high temperature occurs, and the strength is increased to form defect points. May not be high.
In making the flame resistant, an elongation operation of preferably 0 to 10%, more preferably 3 to 8% is performed. Proper elongation in the flameproofing furnace is necessary to maintain and improve the orientation of the fibril structure forming the fibers. If the elongation is less than 0%, the orientation of the fibril structure cannot be maintained, the orientation at the fiber axis becomes insufficient, and the mechanical performance tends not to increase. On the other hand, when the elongation exceeds 10%, the fibril structure itself breaks, and the subsequent formation of the carbon fiber structure is impaired, and the break point becomes a defect point, and the strength of the carbon fiber may not be increased.

In carbonization, the flame-resistant fiber obtained above is passed through a first carbonization furnace made inert by nitrogen or the like while being stretched, and then stretched to be a second atmosphere made inert. It is passed through a carbonization furnace to obtain carbon fibers.
In the first carbonization furnace, a linear temperature gradient is formed at a treatment temperature of preferably 300 to 800 ° C, more preferably 300 to 750 ° C. If the treatment temperature is less than 300 ° C., the temperature is almost the same as that of flame resistance, which is inconvenient. If the treatment temperature exceeds 800 ° C., the process yarn becomes brittle and it may be difficult to transfer to the next process.
In the elongation in the first carbonization furnace, the elongation rate is preferably 2 to 7%, and more preferably 3 to 5%. If the draw ratio is less than 2%, the orientation of the fibril structure cannot be maintained, the orientation at the fiber axis becomes insufficient, and the mechanical performance tends not to increase. On the other hand, if the elongation rate exceeds 7%, the fibril structure itself breaks, and the subsequent formation of the carbon fiber structure is impaired. Further, the break point becomes a defect point, and the strength of the carbon fiber may not be increased.
The treatment time in the first carbonization furnace is preferably 1.0 to 3.0 minutes, and more preferably 1.2 to 2.5 minutes. When the treatment time is less than 1.0 minute, a severe decomposition reaction accompanying a rapid temperature rise occurs, and the strength of the carbon fiber may not be increased. When the treatment time exceeds 3.0 minutes, the effect of plasticization in the first half of the process occurs, and the degree of crystal orientation tends to decrease, so the mechanical performance of the resulting carbon fiber tends to be impaired.

In the second carbonization furnace, the processing temperature is preferably 1000 to 1600 ° C, more preferably 1050 to 1600 ° C. The lower the maximum temperature at the treatment temperature, the more the mechanical properties of the resulting carbon fiber can be improved.
The shorter the treatment time in the second carbonization furnace, the higher the productivity, and the longer the treatment time, the lower the maximum treatment temperature, and the formation of defect points can be suppressed. Specifically, the treatment time is preferably 1.3 to 5.0 minutes, and more preferably 2.0 to 4.2 minutes.
In the heat treatment in the second carbonization furnace, the process fibers are accompanied by a large shrinkage, and therefore, it is preferable to perform them under tension. The elongation percentage at that time is preferably −6.0 to 0.0%, more preferably −5.0 to −1.0%. When the elongation percentage is less than -6.0%, the crystal orientation in the fiber axis direction becomes low, and sufficient tensile properties may not be obtained. On the other hand, if the elongation rate exceeds 0.0%, the structure that has been formed so far is destroyed and defect points are formed, which may cause a significant decrease in strength.
If necessary, heat treatment may be performed in the third carbonization furnace after the heat treatment in the second carbonization furnace.

The obtained carbon fiber is preferably subjected to surface oxidation treatment.
Examples of the surface treatment method include oxidation treatment such as electrolytic oxidation, chemical oxidation, and air oxidation. Among these, electrolytic oxidation is preferable because stable surface oxidation treatment is possible and it is widely used industrially.
In the surface oxidation treatment, it is preferable to set ipa representing the surface treatment state to 0.05 to 0.25 μA / cm ² . In order to control within such a range, a method of adjusting the amount of electricity by electrolytic oxidation treatment is simple. In the electrolytic oxidation treatment, even if the amount of electricity is the same, ipa varies greatly depending on the electrolyte to be used and its concentration. However, in an alkaline aqueous solution having a pH of more than 7, the electric power of 10 to 200 coulomb / g with carbon fiber as the anode. It is preferable to carry out the oxidation treatment by flowing an amount. As the electrolyte, ammonium carbonate, ammonium bicarbonate, ammonium sulfate, calcium hydroxide, sodium hydroxide, potassium hydroxide and the like are suitable.

The carbon fiber may be subjected to sizing treatment.
In the sizing treatment, a sizing agent dissolved in an organic solvent or a sizing agent emulsion dispersed in water with an emulsifier is applied to the carbon fiber bundle by a roller dipping method, a roller contact method, etc., and dried. It can be carried out.
The adhesion amount of the sizing agent to the surface of the carbon fiber can be controlled by adjusting the concentration of the sizing agent solution or adjusting the squeezing amount. Drying can be performed using hot air, a hot plate, a heating roller, various infrared heaters, and the like.

As the sizing agent, (a) an epoxy resin having a hydroxy group, (b) a polyhydroxy compound, (c) a polyurethane obtained from a diisocyanate containing an aromatic ring, (d) a mixture of the epoxy resin, the polyurethane and (d ) Urethane-modified epoxy resin which is a reaction product of epoxy resin.
The epoxy group has a very strong interaction with the oxygen-containing functional group on the surface of the carbon fiber, and can be firmly adhered to the carbon fiber surface of the sizing agent component. Further, by having a urethane bond unit composed of a polyhydroxy compound and a diisocyanate containing an aromatic ring, it becomes possible to give flexibility and to give a strong interaction between the urethane bond and the carbon fiber surface due to the polarity of the aromatic ring. Therefore, the urethane-modified epoxy resin having an epoxy group and the above-mentioned urethane bond unit in the molecule is a flexible compound that adheres strongly to the carbon fiber surface, and in the compounding process in which the matrix resin is impregnated and cured, the carbon fiber surface A flexible interface layer firmly bonded to each other can be formed. Therefore, a composite material having more excellent mechanical performance can be obtained.

(A) As the epoxy resin having a hydroxy group, for example, glycidol, methyl glycidol, bisphenol F type epoxy resin, bisphenol A type epoxy resin, oxycarboxylic acid glycidyl ester epoxy resin and the like can be used. Among these, bisphenol type epoxy resins are preferable. Since the bisphenol type epoxy resin has an aromatic ring, it has a strong interaction with the carbon fiber surface, and is an epoxy resin having an aromatic ring that is suitably used from the viewpoint of heat resistance and rigidity as a resin used in a composite material. Excellent compatibility with.
(B) As the hydroxy compound, an alkylene oxide adduct of bisphenol A, an aliphatic polyhydroxy compound, a polyhydroxymonocarboxy compound, or a mixture of two or more of these is preferable. This is because these compounds can make the urethane-modified epoxy resin flexible.
(C) The diisocyanate containing an aromatic ring is preferably toluene diisocyanate or xylene diisocyanate.
(D) As an epoxy resin, what has two or more epoxy groups in a molecule | numerator is preferable. This is because when two or more epoxy groups are present, the interaction with the surface of the carbon fiber is strong and adheres firmly. There is no restriction | limiting in particular as a kind of epoxy group, A glycidyl type, an alicyclic epoxy group, etc. are employable.
More preferable epoxy resins include bisphenol F type epoxy resin, bisphenol A type epoxy resin, novolac type epoxy resin, dicyclopentadiene type epoxy resin (Epiclon HP-7200 series: DIC Corporation), and trishydroxyn phenylmethane type epoxy resin. (Epicoat 1032H60, 1032S50: Japan Epoxy Resin Co., Ltd.), DPP novolac epoxy resin (Epicoat 157S65, 157S70: Japan Epoxy Resin Co., Ltd.), bisphenol A alkylene oxide-added epoxy resin, and the like.

(A) An epoxy resin having a hydroxy group, (b) a polyhydroxy compound, (c) a polyurethane obtained from a diisocyanate containing an aromatic ring, and (d) a mixture or a reaction product of an epoxy resin, (A) to (d) may be mixed at the same time, or after synthesizing polyurethane from (a) to (c), the diisocyanate compound and (d) may be added and reacted. Good.
Examples of the aqueous dispersion containing the reaction products (a) to (d) include hydran N320 (manufactured by DIC Corporation).

In order to obtain the composite material laminate 1, first, a large number of carbon fibers obtained as described above are fed out using a fiber feeding device or the like and opened as necessary. Examples of the fiber opening method include blowing air to the carbon fiber, imparting longitudinal vibration of the carbon fiber, imparting lateral vibration of the carbon fiber, and a combination thereof.
Next, the opened fibers are aligned in one direction, and the aligned state is impregnated with uncured resin to obtain a unidirectional prepreg.
As a resin impregnation method, for example, an uncured resin is applied in advance to a release sheet, and the aligned carbon fibers are placed on the applied resin and passed through a roller. The resin is applied to the aligned carbon fibers. The method of apply | coating and letting a roller pass is mentioned. Here, the thickness of the obtained unidirectional prepreg can be adjusted by adjusting the gap between the rolls. Moreover, if the viscosity of resin is reduced by heating a roll, the thickness of a unidirectional prepreg can be equalized easily.
Next, four obtained unidirectional prepregs were prepared, and the carbon fibers were oriented so as to form the 45 ° oriented layer 10, the 0 ° oriented layer 20, the −45 ° oriented layer 30 and the 90 ° oriented layer 40. Four unidirectional prepregs are stacked. Next, the composite material laminate 1 is obtained by heating to cure the resin.

In the composite material laminated board 1 demonstrated above, the maximum height difference of the surface of a single fiber is 5-25 nm, the average unevenness | corrugation degree is 2-6 nm, and the ratio of the major axis and minor axis of the cross section of a single fiber is 1.00-1. 01, carbon fibers having a tensile elongation of 2.2% or more are used, and the 45 ° orientation layer 10, the −45 ° orientation layer 30 and the 90 ° orientation layer 40 have a thickness of 0.04 mm or less. The tensile properties of the alignment layer 10, the -45 ° alignment layer 30, and the 90 ° alignment layer 40 are improved. Therefore, the tensile elongation of the composite material laminate 1 in the 0 ° direction is increased, specifically, 2.1% or more.
Further, the composite laminate 1 including the 45 ° oriented layer 10, the 0 ° oriented layer 20, the −45 ° oriented layer 30 and the 90 ° oriented layer 40 has a pseudo-isotropic tensile elongation.

Note that the present invention is not limited to the above embodiment.
For example, the composite material laminate of the present invention is, for example, a 0 ° orientation layer and a 90 ° orientation other than a four-layer laminate of a 45 ° orientation layer, a 0 ° orientation layer, a −45 ° orientation layer, and a 90 ° orientation layer. A two-layer laminate with two layers, a three-layer laminate with a 0 ° oriented layer, a 90 ° oriented layer and a 0 ° oriented layer, a 0 ° oriented layer, a 90 ° oriented layer, a 90 ° oriented layer and a 0 ° oriented layer It may be a four-layer laminate. Even in these cases, the tensile elongation is increased by setting the thickness of the 90 ° alignment layer to 0.04 mm or less. Also, in the laminated plates of the other embodiment examples, since the arrangement pattern of the carbon fibers is symmetric, it is a pseudo isotropic laminated plate.
Furthermore, the layer other than the 0 ° orientation layer (the orientation layer in the other direction) is not a 90 ° orientation layer, a 45 ° orientation layer or a −45 ° orientation layer but a layer containing carbon fibers oriented in other directions. May be. In this case, if the arrangement of all the carbon fibers contained in the composite material laminate is axisymmetric about 0 °, the tensile elongation of the composite material laminate becomes pseudo-isotropic.

Example 1
(1) Production of carbon fiber bundle An acrylonitrile-based polymer having 98% by mass of acrylonitrile units and 2% by mass of methacrylic acid units was dissolved in dimethylformamide to prepare a 23.5% by mass spinning solution.
The prepared spinning solution was once spun into air from a spinneret in which discharge holes having a diameter of 150 μm and a number of holes of 2000 were formed, and then passed through a space of about 5 mm. Then, it consisted of the aqueous solution containing 79.0 mass% dimethylformamide adjusted to 10 degreeC, and it discharged and coagulated in the coagulation liquid adjusted to 10 degreeC, and obtained the coagulated yarn.
Next, the film was stretched 1.1 times in air, and then stretched 2.9 times in a stretching tank filled with an aqueous solution containing 35 mass% dimethylformamide adjusted to 60 ° C. After stretching, the process fiber bundle containing the solvent was washed with clean water, and then stretched 1.2 times in 95 ° C. hot water.
Subsequently, 1.1 mass% of water-based fiber oil agent was made to adhere to the obtained fiber bundle, and it dried and densified. Here, the following were used as the water-based fiber oil agent.
Amino-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KF-865) 85% by mass and emulsifier (manufactured by Nikko Chemicals Co., Ltd., product name: NIKKOL BL-9EX (POE (9) lauryl ether)) 15 mass % To obtain an aqueous dispersion by the phase inversion emulsification method.
The fiber bundle after drying and densification was stretched 2.6 times between heated rolls, and after further improving the orientation and densification, it was wound up to obtain an acrylonitrile-based precursor fiber bundle. The fineness of the acrylonitrile-based precursor fiber filament was 0.77 dtex.
Next, the obtained precursor fiber bundle is introduced into a flameproofing furnace in a state in which a plurality of the precursor fiber bundles are arranged in parallel, and the precursor fiber bundle is made flameproof by blowing air heated to 220 to 260 ° C. to the precursor fiber bundle. To obtain a flame resistant fiber bundle having a density of 1.345 g / cm ³ . At that time, the elongation rate was 6.0%, and the flameproofing treatment time was 42 minutes.
Subsequently, the flame-resistant fiber bundle was passed through nitrogen in a first carbonization furnace having a temperature gradient of 300 to 700 ° C. while adding 4.5% elongation. The temperature gradient was set to be linear. The processing time was 2.0 minutes.
Further, heat treatment was performed using a second carbonization furnace in which a temperature gradient of 1050 to 1250 ° C. was set in a nitrogen atmosphere, and subsequently a third carbonization furnace in which a temperature gradient of 1250 to 1450 ° C. was set in a nitrogen atmosphere was used. To obtain a carbon fiber bundle. At that time, the total elongation in the second and third carbonization furnaces was -4.0%, and the treatment time was 3.5 minutes. Subsequently, the sample was run in a 10% by weight ammonium bicarbonate aqueous solution, and an electric current treatment was performed between the counter electrode and the carbon fiber bundle as an anode so that the amount of electricity was 40 coulomb per 1 g of the carbon fiber to be treated. Subsequently, it was washed with hot water 90 ° C. and then dried.
Next, 0.5% by mass of hydran N320 was adhered and wound around a bobbin to obtain a wound body of carbon fiber bundles.
With respect to the obtained carbon fiber bundle, the maximum height difference on the single fiber surface, the average unevenness, the ratio of the major axis to the minor axis of the cross section, and the tensile elongation were measured as follows. The measurement results are shown in Table 1. In Table 1, the carbon fiber bundle obtained by the above method is represented as “CF1”.

(Measurement of maximum height difference of single fiber surface, average roughness)
Both ends of the single fiber were fixed with a carbon paste on a metal sample stand (20 mm diameter) “Epolide Service, product number: KY10200167” attached to a scanning probe microscope, and measurement was performed under the following conditions.
[Scanning probe microscope measurement conditions]
Apparatus: “SPI4000 probe station, SPA400 (unit)” manufactured by SII Nanotechnology Inc. Scanning mode: Dynamic force mode (DFM) (shape image measurement)
Probe: "SI-DF-20", manufactured by SII Nano Technology
Scanning range: 2.5 μm × 2.5 μm
Rotation: 90 ° (scan in the direction perpendicular to the fiber axis direction)
Scanning speed: 1.0Hz
Number of pixels: 512 × 512
Measurement environment: at room temperature and in the air For one single fiber, one image was obtained under the above conditions, and the obtained image was measured using the image analysis software (SPIWin) attached to the scanning probe microscope to obtain the average unevenness and maximum The height difference was determined.

(Measurement of ratio between major axis and minor axis of single fiber cross section)
The ratio of the major axis to the minor axis (major axis / minor axis) of the fiber cross section of the single fiber constituting the carbon fiber bundle was measured as follows.
A carbon fiber bundle for measurement was passed through a tube made of vinyl chloride resin having an inner diameter of 1 mm, and this was then cut into round pieces with a knife to prepare a sample. Next, the sample was adhered to a sample stage of a scanning electron microscope (XL20 manufactured by Philips) with the fiber cross section facing upward, and gold was sputtered to a thickness of about 10 nm. Then, using the scanning electron microscope, the fiber cross section is observed under the conditions of the acceleration voltage of 7.00 kV and the working distance of 31 mm, the major axis and minor axis of the fiber section of the single fiber are measured, and the ratio of major axis / minor axis is obtained. It was.

(Measurement of tensile elongation of carbon fiber bundle)
The tensile properties (tensile strength, tensile modulus, tensile elongation) of the carbon fiber bundle were measured and evaluated according to JIS R7601.

(2) Production of Composite Material Laminate Forty carbon fiber bundles unwound from the bobbin were opened by air blowing and longitudinal vibration, and then aligned in one direction. The aligned fibers were placed on a B-staged epoxy resin (# 350, 130 ° C. curing type, manufactured by Mitsubishi Rayon Co., Ltd.) on a release paper. This was passed through a thermocompression roller (set temperature 110 ° C.) to impregnate the carbon fiber bundle with an epoxy resin. A protective film was laminated thereon to produce a unidirectional prepreg (hereinafter referred to as UD prepreg). At that time, the lip opening degree of the thermocompression bonding roll was adjusted, and the thickness of the obtained unidirectional prepreg was adjusted to 0.025 mm.
Next, four unidirectional prepregs obtained are prepared, and the carbon fibers of the unidirectional prepreg are oriented so as to form a 45 ° oriented layer, a 0 ° oriented layer, a −45 ° oriented layer, and a 90 ° oriented layer. Meanwhile, four unidirectional prepregs were laminated. This was made into one set of laminates, and a total of 20 sets (ie, 80 layers) were laminated ({[45/0 / −45 / 90] ₁₀ } _s ). Subsequently, it heated at 130 degreeC, the resin was hardened, and the composite material laminated board of thickness 1.9mm was manufactured.

(3) Evaluation The obtained composite laminate was subjected to a tensile test in the 0 ° direction in accordance with ASTM D3039, and the tensile properties (tensile strength, tensile elastic modulus, tensile elongation) were measured. The measurement results are shown in Table 1.
Moreover, the evaluation method based on ASTM D790 (L / D = 16) which manufactured the unidirectional composite material laminated board of thickness 2.0mm using the said unidirectional prepreg, and the bending strength of the 90 degree direction of the laminated board It was measured by. The measurement results are shown in Table 1.

(Example 2)
Using CF1, a unidirectional prepreg having a thickness of 0.04 mm was produced in the same manner as in Example 1. Next, four unidirectional prepregs obtained are prepared, and the carbon fibers of the unidirectional prepreg are oriented so as to form a 45 ° oriented layer, a 0 ° oriented layer, a −45 ° oriented layer, and a 90 ° oriented layer. Meanwhile, four unidirectional prepregs were laminated. This was regarded as one set of laminates, and a total of 12 sets (ie, 48 layers) were laminated ({[45/0 / −45 / 90] ₆ } _s ). Subsequently, it heated at 130 degreeC, the resin was hardened, and the composite material laminated board of thickness 1.9mm was manufactured. About the obtained composite material laminated board, the tensile test of the 0 degree direction was done based on ASTM D3039, and the tensile characteristics (tensile strength, tensile elastic modulus, tensile elongation) were measured. The measurement results are shown in Table 1. Moreover, the evaluation method based on ASTM D790 (L / D = 16) which manufactured the unidirectional composite material laminated board of thickness 2.0mm using the said unidirectional prepreg, and the bending strength of the 90 degree direction of the laminated board It was measured by. The measurement results are shown in Table 1.

(Example 3)
A carbon fiber bundle was produced in the same manner as in Example 1 except that the third carbonization furnace was not used. In the second carbonization furnace, a temperature gradient of 1050 to 1250 ° C. was set in a nitrogen atmosphere, the elongation rate was −3.9%, and the treatment time was 1.8 minutes.
With respect to the obtained carbon fiber bundle, the maximum height difference of the single fiber surface, the average unevenness, the ratio of the major axis to the minor axis of the cross section, and the tensile elongation were measured. The measurement results are shown in Table 1. In Table 1, the carbon fiber bundle obtained by the above method is expressed as “CF2”.
And using this CF2, the composite material laminated board was manufactured similarly to Example 1, and evaluation was implemented. The evaluation results are shown in Table 1.

Example 4
An acrylonitrile polymer having 98% by mass of acrylonitrile units and 2% by mass of methacrylic acid units was dissolved in dimethylformamide to prepare a 23.5% by mass spinning stock solution.
The prepared spinning solution was once spun into air from a spinneret in which discharge holes having a diameter of 150 μm and a number of holes of 2000 were formed, and then passed through a space of about 5 mm. Then, it consisted of the aqueous solution containing 79.5 mass% dimethylformamide adjusted to 10 degreeC, and it discharged and solidified in the coagulation liquid adjusted to 10 degreeC, and obtained the coagulated thread | yarn.
Next, the film was stretched 1.1 times in air, and then stretched 3.5 times in a stretching tank filled with an aqueous solution containing 60% by mass dimethylformamide adjusted to 70 ° C. After stretching, the process fiber bundle containing the solvent was washed with clean water, and then stretched 1.3 times in 95 ° C. hot water.
Next, 1.1% by mass of an oil agent mainly composed of amino-modified silicone similar to that in Example 1 was attached to the obtained fiber bundle, and dried and densified. The fiber bundle after drying and densification was stretched 2.8 times between heating rolls, and after further improving the orientation and densification, it was wound up to obtain an acrylonitrile-based precursor fiber bundle. The fineness of the acrylonitrile-based precursor fiber filament was 0.77 dtex.
Next, the obtained precursor fiber bundle is introduced into a flameproofing furnace in a state in which a plurality of the precursor fiber bundles are arranged in parallel, and the precursor fiber bundle is made flameproof by blowing air heated to 220 to 260 ° C. to the precursor fiber bundle. To obtain a flame resistant fiber bundle having a density of 1.345 g / cm ³ . At that time, the elongation rate was 6.0%, and the flameproofing treatment time was 42 minutes.
Subsequently, the flame-resistant fiber bundle was passed through nitrogen in a first carbonization furnace having a temperature gradient of 300 to 700 ° C. while adding 4.5% elongation. The temperature gradient was set to be linear. The processing time was 1.9 minutes.
Furthermore, heat treatment was performed at an elongation of -3.8% using a second carbonization furnace in which a temperature gradient of 1000 to 1250 ° C. was set in a nitrogen atmosphere, and subsequently a temperature gradient of 1250 to 1450 ° C. was set in the nitrogen atmosphere. A carbon fiber bundle was obtained by performing a heat treatment at an elongation of -0.1% using the third carbonization furnace. The total elongation in the second and third carbonization furnaces was -3.9%, and the treatment time was 3.7 minutes. Subsequently, the sample was run in a 10% by weight ammonium bicarbonate aqueous solution, and an electric current treatment was performed between the counter electrode and the carbon fiber bundle as an anode so that the amount of electricity was 40 coulomb per 1 g of the carbon fiber to be treated. Subsequently, it was washed with hot water 90 ° C. and then dried.
Next, 0.5% by mass of hydran N320 was adhered and wound around a bobbin to obtain a wound body of carbon fiber bundles.
With respect to the obtained carbon fiber bundle, the maximum height difference of the single fiber surface, the average unevenness, the ratio of the major axis to the minor axis of the cross section, and the tensile elongation were measured. The measurement results are shown in Table 1. In Table 1, the carbon fiber bundle obtained by the above method is represented as “CF3”.
And using this CF3, it carried out similarly to Example 1, manufactured the composite material laminated board, and implemented evaluation. The evaluation results are shown in Table 1.

(Comparative Example 1)
Two unidirectional prepregs having a thickness of 0.025 mm prepared in Example 1 were stacked to prepare a unidirectional prepreg of 0.050 mm. Next, four unidirectional prepregs of 0.050 mm obtained were prepared, and carbon of the unidirectional prepreg was formed so as to form a 45 ° oriented layer, a 0 ° oriented layer, a −45 ° oriented layer, and a 90 ° oriented layer. Four unidirectional prepregs were laminated while orienting the fibers. This was one set stack of a total of 10 sets (i.e., 40 layers) were laminated _{({[45 2/0 2} / -45 2/90 2] 5} s). Subsequently, it heated at 130 degreeC, the resin was hardened, the composite material laminated board of thickness 1.9mm was manufactured, and the tensile characteristic of 0 degree direction was measured. The measurement results are shown in Table 1. Moreover, the evaluation method based on ASTM D790 (L / D = 16) which manufactured the unidirectional composite material laminated board of thickness 2.0mm using the said unidirectional prepreg, and the bending strength of the 90 degree direction of the laminated board It was measured by. The measurement results are shown in Table 1.

(Comparative Example 2)
A unidirectional prepreg with a thickness of 0.08 mm was produced using CF 2 in the same manner as in Example 1. Next, four unidirectional prepregs obtained are prepared, and the carbon fibers of the unidirectional prepreg are oriented so as to form a 45 ° oriented layer, a 0 ° oriented layer, a −45 ° oriented layer, and a 90 ° oriented layer. Meanwhile, four unidirectional prepregs were laminated. This was regarded as one set of laminates, and a total of 12 sets (ie, 48 layers) were laminated ({[45/0 / −45 / 90] ₆ } _s ). Subsequently, it heated at 130 degreeC, the resin was hardened, and the composite material laminated board of thickness 1.9mm was manufactured. About the obtained composite material laminated board, the tensile test of the 0 degree direction was done based on ASTM D3039, and the tensile characteristics (tensile strength, tensile elastic modulus, tensile elongation) were measured. Moreover, the evaluation method based on ASTM D790 (L / D = 16) which manufactured the unidirectional composite material laminated board of thickness 2.0mm using the said unidirectional prepreg, and the bending strength of the 90 degree direction of the laminated board It was measured by. The measurement results are shown in Table 1.

(Comparative Example 3)
A composite laminate with a thickness of 1.9 mm was produced in the same manner as in Example 1 except that the carbon fiber was changed to Mitsubishi Rayon TR50S, and the tensile properties in the 0 ° direction and the unidirectional composite with a thickness of 2 mm were produced. A material laminate was manufactured and the bending strength in the 90 ° direction was measured. The measurement results are shown in Table 1.

(Comparative Example 4)
A composite material laminate having a thickness of 2.03 mm was produced in the same manner as in Example 2 except that the carbon fiber was changed to MR60H manufactured by Mitsubishi Rayon Co., Ltd. and the thickness of the unidirectional prepreg was changed to 0.042 mm. Directional tensile properties and a unidirectional composite laminate with a thickness of 2 mm were produced, and the bending strength in the 90 ° direction was measured. The measurement results are shown in Table 1.

The maximum height difference on the single fiber surface is 10 to 45 nm, the average unevenness is 3 to 7 nm, the ratio of the major axis to the minor axis of the single fiber cross section is 1.00 to 1.01, and the tensile elongation is 2. The composite material laminates of Examples 1 to 4 using 2% or more of carbon fiber and having a 45 ° -oriented layer, a −45 ° -oriented layer and a 90 ° -oriented layer having a thickness of 0.044 mm or less are The tensile elongation was 2.1% or more.
On the other hand, the same CF as in Example 1 was used, but the composite material laminate of Comparative Example 1 in which the thickness of the 45 ° oriented layer, the −45 ° oriented layer and the 90 ° oriented layer was 0.050 mm, The tensile elongation in the 0 ° direction was less than 2.1%.
The same CF as in Example 3 was used, but the composite material laminate of Comparative Example 2 in which the thickness of the 45 ° oriented layer, the −45 ° oriented layer and the 90 ° oriented layer was 0.080 mm was 0 ° The tensile elongation in the direction was less than 2.1%.
The carbon fiber TR50S is used which has a maximum height difference of 10 to 45 nm on the surface of the single fiber, an average unevenness of 3 to 7 nm, and a ratio of the major axis to the minor axis of the single fiber cross section is not in the range of 1.00 to 1.01. The composite laminate of Comparative Example 3 had a tensile elongation in the 0 ° direction of less than 2.1%.
Carbon fiber MR60H having a maximum height difference of 10 to 45 nm on the surface of the single fiber, a ratio of the major axis to the minor axis of the single fiber cross section of 1.00 to 1.01, and a tensile elongation of 2.2% or more. The composite laminate of Comparative Example 3 using the tensile elongation in the 0 ° direction was less than 2.1%.

  Since the composite material laminate of the present invention has good tensile properties, it is suitably used for applications that require high strength, such as aircraft, automobiles, and railway vehicles.

1 Composite material laminated board 10 45 ° orientation layer
20 ° alignment layer 30-45 ° alignment layer (other direction alignment layer)
40 90 ° orientation layer (other direction orientation layer)

Claims (3)

One or more layers having a thickness of 0.044 mm or less containing a carbon fiber oriented at 0 ° relative to the reference direction and a 0 ° oriented layer containing a resin, a carbon fiber oriented in a direction other than 0 °, and a resin Other direction orientation layer,
The carbon fibers contained in the 0 ° orientation layer and the other-direction orientation layer have a maximum height difference of 10 to 45 nm, an average roughness of 3 to 7 nm, and a ratio of the major axis to the minor axis of the cross section of the single fiber. A composite laminate having a fiber bundle of 1.00 to 1.01 and a tensile elongation of 2.2% or more.   The composite material laminate according to claim 1, wherein the other-direction oriented layer is one or two layers, and is a 90 ° oriented layer in which carbon fibers are oriented at approximately 90 ° with respect to the reference direction.   The other direction orientation layers are three layers, a 90 ° orientation layer in which carbon fibers are oriented at about 90 ° with respect to the reference direction, a 45 ° orientation layer in which the carbon fibers are oriented at about 45 ° with respect to the reference direction, and carbon The composite laminate according to claim 1, wherein the fiber is a −45 ° oriented layer in which the fibers are oriented at approximately −45 ° with respect to the reference direction.

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