JP2018161800A - Fiber reinforced resin molded product and metal hybrid structure member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid structural member of a fiber-reinforced resin molded body and a metal having excellent lightness and high impact resistance. SOLUTION: A hybrid structural member of a fiber reinforced resin molded body and a metal in which the following fiber reinforced resin molded body (1) and a metal are integrated via an adhesive (2). <Fiber-reinforced resin molded product (1)> A fiber-reinforced resin molded product containing a fiber bundle in which a plurality of reinforcing fibers are bundled and a matrix resin, and is 0 on the cut surface of the fiber-reinforced resin molded product in the thickness direction. The fluctuation coefficient of the reinforcing fiber content per unit section of 1 mm square is 40% or less. <Adhesive (2)> An adhesive having an elastic modulus of 2 GPa or less. [Selection diagram] None

Description

  The present invention relates to a hybrid structural member made of a fiber-reinforced resin molded product and a metal, and more particularly to a dissimilar material structural member that can be used in a vehicle.

  The fiber reinforced resin molded product and metal hybrid structure member can emit both the excellent lightness and high mechanical properties of the fiber reinforced resin molded product and the impact resistance of the metal. As a method for integrating the molded product and the metal, a method in which the fiber-reinforced resin molded product and the metal are bonded and integrated, or mechanically joined with a bolt or the like is known.

  However, a fiber reinforced resin molded article obtained by simply bonding a fiber reinforced resin molded article and a metal to a metal hybrid structure member has a low adhesive strength and may not exhibit predetermined characteristics.

  A structure (for example, Patent Document 1) with improved adhesion between a fiber-reinforced resin molded product and a metal, or a structure (for example, Patent Documents 2 and 3) with improved adhesiveness by increasing the toughness of the adhesive itself. Although proposed, peeling at the interface between the fiber reinforced resin molded product and the adhesive layer, or the base material of the fiber reinforced resin molded product is broken, and sufficient adhesive strength is not obtained.

JP 2006-297927 A JP 58-189277 A JP 2004-263104 A

  The present invention is intended to solve the problems associated with the prior art as described above, and improves the adhesion between the fiber reinforced resin molded product and the metal, and has excellent light weight and high impact resistance. An object of the present invention is to provide a hybrid structure member made of a fiber-reinforced resin and a metal.

As a result of intensive research to solve the above-mentioned problems, the present inventor has achieved excellent lightness and high performance by using a fiber-reinforced resin molded product and a metal whose fiber dispersibility of the fiber-reinforced resin molded product is improved. It has been found that a fiber-reinforced resin molded article and metal hybrid structure member having excellent impact resistance and the like can be provided. That is, the gist of the present invention resides in the following [1] to [8].

[1] A hybrid structure member of a fiber-reinforced resin molded body and a metal, in which the following fiber-reinforced resin molded body (1) and a metal are integrated via an adhesive (2).
<Fiber reinforced resin molding (1)>
A fiber-reinforced resin molded body containing a fiber bundle in which a plurality of reinforcing fibers are bundled and a matrix resin, and the reinforcing fiber per unit section of 0.1 mm square on the cut surface in the thickness direction of the fiber-reinforced resin molded body The variation coefficient of the content rate is 40% or less.
<Adhesive (2)>
An adhesive having an elastic modulus of 2 GPa or less.
[2] The hybrid structure member according to [1], wherein the hybrid structure member has a tensile adhesive shear strength at 23 ° C. of 14 MPa or more.
[3] The hybrid structure member according to the above [1] or [2], wherein an average fiber length of the reinforcing fibers in the fiber-reinforced resin molded body is 5 to 100 mm.
[4] The hybrid structure member according to any one of the above [1] to [3], wherein a coefficient of variation of the reinforcing fiber content per unit section of 0.1 mm square is 10% or less.
[5] The hybrid structure member according to any one of [1] to [4], wherein the reinforcing fiber is a carbon fiber.
[6] The hybrid structure member according to any one of [1] to [5], wherein the adhesive has a thickness of 0.1 to 4 mm.
[7] The hybrid structure member according to any one of [1] to [5], wherein the adhesive has a thickness of 0.1 to 1 mm.
[8] The hybrid structure member according to any one of [1] to [7], wherein the adhesive is an epoxy adhesive.

  ADVANTAGE OF THE INVENTION According to this invention, the fiber reinforced resin molded object and metal hybrid structure member which have the outstanding lightness, high impact resistance, etc. can be provided.

In the fiber-reinforced resin molded body and metal hybrid structure member of the present invention, the following fiber-reinforced resin molded body (1) and metal are integrated via an adhesive (2).
<Fiber reinforced resin molding (1)>
A fiber-reinforced resin molded body containing a fiber bundle in which a plurality of reinforcing fibers are bundled and a matrix resin, and the reinforcing fiber per unit section of 0.1 mm square on the cut surface in the thickness direction of the fiber-reinforced resin molded body The variation coefficient of the content rate is 40% or less.
<Adhesive (2)>
An adhesive having an elastic modulus of 2 GPa or less.
Hereinafter, the fiber-reinforced resin molded body and metal hybrid structure member of the present invention will be described in detail.

(Fiber reinforced resin molding (1))
The fiber-reinforced resin molded product that can be used for the hybrid structure member of the present invention contains reinforcing fibers and a matrix resin. The fiber reinforced resin molded article of the present invention can be obtained, for example, by molding a fiber reinforced resin material (SMC) in which a matrix resin is contained in a fiber bundle group composed of a plurality of fiber bundles.

(Matrix resin)
As the matrix resin, a thermosetting resin or a thermoplastic resin can be used. As a matrix resin, only a thermosetting resin may be used, only a thermoplastic resin may be used, and both a thermosetting resin and a thermoplastic resin may be used.
When manufacturing the fiber reinforced resin molding of this invention from SMC, as a matrix resin, a thermosetting resin is preferable.

The thermosetting resin is not particularly limited, and includes epoxy resin, phenol resin, unsaturated polyester resin, vinyl ester resin, phenoxy resin, alkyd resin, urethane resin, urea resin, melamine resin, maleimide resin, cyanate resin, and the like. Can be mentioned.
A thermosetting resin may be used individually by 1 type, and may use 2 or more types together.

  Examples of the thermoplastic resin include polyolefin resins, polyamide resins, polyester resins, polyphenylene sulfide resins, polyetheretherketone resins, polyethersulfone resins, and aromatic polyamide resins. A thermoplastic resin may be used individually by 1 type, and may use 2 or more types together.

(Reinforced fiber)
As the reinforcing fiber that can be used in the fiber-reinforced resin molded article of the present invention, the type of reinforcing fiber is not particularly limited, and inorganic fiber, organic fiber, metal fiber, or a hybrid fiber that combines these can be used. . Examples of the inorganic fiber include carbon fiber, graphite fiber, silicon carbide fiber, alumina fiber, tungsten carbide fiber, boron fiber, and glass fiber. Examples of organic fibers include aramid fibers, high density polyethylene fibers, other general nylon fibers, and polyesters. Examples of the metal fibers include fibers such as stainless steel and iron, and may be carbon fibers coated with metal. Among these, carbon fibers are preferable in consideration of mechanical properties such as strength of the final molded product. Moreover, it is preferable that the average fiber diameter of a reinforced fiber is 1-50 micrometers, and it is more preferable that it is 5-20 micrometers.

(Carbon fiber)
The carbon fiber is not particularly limited, and any carbon fiber such as polyacrylonitrile (PAN), petroleum / coal pitch, rayon, and lignin can be used. In particular, PAN-based carbon fibers using PAN as a raw material are preferable because they are excellent in productivity and mechanical properties on an industrial scale. These are available as commercial products.

  The carbon fiber that can be used in the fiber-reinforced resin molded article of the present invention is preferably subjected to surface treatment, particularly electrolytic treatment. Examples of the surface treatment agent include an epoxy sizing agent, a urethane sizing agent, a nylon sizing agent, and an olefin sizing agent. By performing the surface treatment, an advantage that tensile strength and bending strength are improved can be obtained.

(Fiber content, coefficient of variation of fiber content)
The fiber reinforced resin molded article of the present invention has a variation coefficient (hereinafter also referred to as “variation coefficient Q”) of the fiber content of the reinforcing fibers per 0.1 mm square unit section on the cut surface along the thickness. 40% or less.

If the coefficient of variation Q is 40% or less, the fibers are evenly dispersed in the fiber-reinforced resin molded body, and the resin-rich portion is suppressed. Variation is suppressed.
The coefficient of variation Q is obtained by cutting the fiber reinforced resin molded product along the thickness direction, measuring the fiber content of the reinforcing fiber per 0.1 mm unit section at 2000 points on the cut surface, and calculating the standard deviation thereof. An average value (hereinafter referred to as “average value P”) is calculated, and means a value obtained by dividing the standard deviation by the average value P.

The upper limit of the coefficient of variation Q in the fiber reinforced resin molded article used in the present invention is 40%, preferably 35%, and more preferably 30%.
If the variation coefficient Q is equal to or less than the upper limit value, a hybrid structure member of the fiber reinforced resin molded body and the metal, in which the variation in the bond strength between the fiber reinforced resin molded body and the metal and the fracture mode is suppressed, is obtained.

  The coefficient of variation Q affects the fiber axis direction of each fiber as well as the dispersion state of the fibers in the fiber-reinforced resin molded body. Specifically, for example, in the case of a fiber bundle having a circular cross-sectional shape, if the angle of the cut surface with respect to the fiber axis direction of the fiber bundle is 90 °, the cross-sectional shape of the fiber bundle on the cut surface is a circular shape. On the other hand, when the angle of the cut surface with respect to the fiber axis direction of the fiber bundle is smaller than 90 °, the cross-sectional shape of the fiber bundle at the cut surface becomes an elliptical shape. As described above, when the fiber axis direction of each fiber bundle is changed, the cross-sectional shape of the fiber bundle per unit section is changed, so that the ratio of the fiber bundle to the cross section is changed, which affects the variation coefficient Q.

  A smaller coefficient of variation Q indicates that the fibers are more evenly dispersed in the fiber-reinforced resin molded body. However, the closer the coefficient of variation Q is to zero, the smaller the change in the cross-sectional shape of the fiber bundle per unit section, that is, the state in which the fiber axis direction of each fiber bundle is aligned in the fiber-reinforced resin molded body. .

  In order to suppress variations in the adhesive strength between the fiber-reinforced resin molded body and the metal and the fracture mode, it is preferable that the fiber direction of each fiber is random. Accordingly, the lower limit value of the coefficient of variation Q is preferably 10%, preferably 12%, and more preferably 15%.

  If the coefficient of variation Q is equal to or greater than the lower limit, a hybrid structure member of a fiber reinforced resin molded body and a metal can be obtained in which variations in the bond strength between the fiber reinforced resin molded body and the metal and the fracture mode are suppressed.

5-100 mm is preferable and, as for the average fiber length of the fiber reinforced resin molding which can be used by this invention, 20-60 mm is more preferable.
If the average fiber length of the fiber reinforced resin molded product is equal to or greater than the lower limit, a fiber reinforced resin molded product having excellent physical properties can be obtained. If the hybrid structure member is obtained and is equal to or less than the above upper limit value, the fiber-reinforced resin material is more likely to flow at the time of molding, so that molding becomes easy.

(Adhesive (2))
Examples of the adhesive used in the present invention include vinyl acetate, polyvinyl alcohol, polyacetal, vinyl chloride, acrylic, polyethylene, cellulose, urea, resorcinol, melamine, and phenol (novolak). Water-soluble), epoxy, polyurethane, polyester, polyimide, polyaromatic, chlorobrene, nitrile rubber, SBR, polysulfide, butyl rubber, silicone rubber, epoxy-nylon, phenol-nitrile Type, epoxy-nitrile type, epoxy-phenol type and the like.

  The elastic modulus of the adhesive used in the present invention is preferably 2 GPa or less. If the elastic modulus of the adhesive is 2 GPa or more, the bond strength between the fiber reinforced resin molded body and the metal is too high, and the fiber reinforced resin molded body is likely to be damaged by the base material. Cannot be obtained.

  0.1-4 mm is preferable and, as for the thickness of the adhesive agent which can be used by this invention, 0.1-1 mm is more preferable. If the thickness of the adhesive layer is less than or equal to the lower limit value, fatigue resistance necessary for the structural member cannot be obtained, and if the thickness is equal to or greater than the upper limit value, physical properties such as impact resistance necessary for the structural member cannot be obtained.

(Method for producing hybrid structure member of fiber-reinforced resin molded product and metal)
The hybrid structural member of the fiber reinforced resin molded product and the metal is coated with the adhesive (2) on the metal and bonded so as to overlap the fiber reinforced resin molded product, at room temperature or appropriately depending on the usage of the adhesive The adhesive can be solidified by heating at a high temperature.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to the invention as described in an Example.

(Fiber content average value P and fiber content variation coefficient Q)
After cutting the fiber reinforced resin moldings of Examples and Comparative Examples in the thickness direction and embedding the cut surface with methacrylic resin (product name “Technobit 4004”, manufactured by Heraeus) so that the cut surface is covered, Polishing was performed to expose the cut surface. Next, the cut surface was imaged with an optical microscope (product name “BX51M”, manufactured by Olympus Corporation) at a magnification of 100 times. The image of the cut surface is divided into 0.1 mm square unit sections by image processing software (product name “Winroof2015, manufactured by Mitani Shoji Co., Ltd.”), and then binarized with a threshold value of 136 as a fiber. Next, for each of the 2000 unit sections, the ratio of the area of the area (area occupied by the fibers) where the luminance is equal to or higher than the threshold is measured for each of the 2000 unit sections. Next, an average value (average value P) and a standard deviation of the fiber content for 2000 unit sections were calculated, and a coefficient of variation Q was calculated by dividing the standard deviation by the average value P.

(Measurement method of adhesive strength)
An adhesive is applied to the tip of the fiber reinforced resin molded body (length 100 mm × width 25 mm × thickness 2 mm) of the examples and comparative examples, and an aluminum substrate (length 100 mm × width 25 mm × thickness 2 mm) as a metal Then, a weight of 1 kg was placed on the top of the laminate and cured by heating at 140 ° C. for 1 hour to obtain a hybrid member of a fiber-reinforced resin molded body and a metal, which was used as a test piece.

Both ends of this test piece were fixed with a machine name, pulled at a speed of 5 mm / min at room temperature, measured for shear strength, and observed for a fracture mode.
In addition, the shear strength is 10 MPa or more, the fracture mode is cohesive failure of the adhesive, the shear strength is 10 MPa or less, the fracture mode is cohesive failure of the adhesive, and the fracture mode is base material fracture or fiber of the fiber reinforced resin molded product. The case where peeling occurred at the interface between the reinforced resin molded product and the metal was evaluated as x.

Example 1
As a fiber (trade name “TR50S15L”, manufactured by Mitsubishi Rayon Co., Ltd.) was used.
75% solution of 1,1-di (t-butylperoxy) cyclohexane as a curing agent (product name) with respect to 100 parts by mass of epoxy acrylate resin (product name: Neopol 8051, manufactured by Nippon Iupika Co., Ltd.) which is a thermosetting resin : Perhexa C-75, manufactured by NOF Corporation) and 0.5 parts by mass of 74% solution of t-butyl peroxyisopropyl carbonate (product name: Kaya-Carbon BIC-75, manufactured by Kayaku Akzo) As an internal mold release agent, 0.35 parts by mass of a phosphate ester derivative composition (product name: MOLD WIZ INT-EQ-6, manufactured by Accel Plastic Research Laboratories, Inc.) is added, and a thickener is added. As a stabilizer, 15.5 parts by mass of modified diphenylmethane diisocyanate (product name: Cosmonate LL, manufactured by Mitsui Chemicals, Inc.) is added as a stabilizer. Nzokinon with the addition of Wako Pure Chemical Industries, Ltd.) 0.02 parts by weight, to obtain a paste containing a matrix resin were mixed by stirring them thoroughly.

  The paste was applied on the first carrier sheet being conveyed to form a first resin sheet having a thickness of 0.45 mm. In addition, a carbon fiber bundle having a thickness of 0.05 mm and a width of 7.5 mm that has been opened and split is cut with a cutting machine, and dropped as a chopped fiber bundle having an average fiber length of 50.8 mm. A sheet-like fiber bundle group was formed. Between the first resin sheet and the cutting machine, a plurality of inclined combs having a circular cross section with a diameter of 3 mm were arranged side by side so as to be parallel to the traveling direction of the first resin sheet. The height of the inclined comb from the first resin sheet was 400 mm, the interval between adjacent inclined combs was 65 mm, and the logarithmic inclination angle was 15 ° in the horizontal direction of the inclined comb. The line speed was 1.5 m / min.

  Above the first carrier sheet, the paste on the second carrier sheet conveyed in the opposite direction of the first carrier sheet is applied to form a second resin sheet having a thickness of 0.45 mm, and the conveying direction is reversed. Then, the second resin sheet was laminated on the sheet-like fiber bundle group. Furthermore, pre-impregnation and main impregnation were performed on the laminate of the first resin sheet, the sheet-like fiber bundle group, and the second resin sheet to obtain a sheet-like fiber-reinforced resin material having a thickness of 2 mm. Pre-impregnation is a concavo-convex roll in which cylindrical convex parts (height of convex parts: 3 mm, area of tip part of convex parts: 38 mm2, pitch of convex parts: 8 mm) are provided in a staggered manner on the outer peripheral surface of the roll, It was performed by 5 pairs of rolls combined with a flat roll. The impregnation was performed with 11 pairs of flat rolls.

The fiber-reinforced resin material obtained was cured at a temperature of 25 ± 5 ° C. for 1 week, cut into 250 mm × 250 mm, and a panel molding die (300 mm × 300 mm × 2 mm, surface chrome) having a fitting number at the end. The plating direction was aligned with the conveying direction (MD direction) of the fiber reinforced resin material in the manufacturing apparatus, and two sheets (total of about 156 g) were put into the center of the mold. Then, the fiber reinforced resin material was heated and pressurized in a mold under conditions of 140 ° C., 8 MPa, and 5 minutes to obtain a fiber reinforced resin molded body.
The obtained fiber-reinforced resin molded product had a fiber content P of 55.7% and a fiber content variation coefficient Q of 26.1%.

  Next, the obtained fiber reinforced material molded body was cut into a length of 100 mm × width of 25 mm, and IW2190 (epoxy adhesive manufactured by 3M) was applied to an area of 12.5 mm × width of 25 mm from the tip, and aluminum # 6000 (length: 100 mm x width: 25 mm x thickness: 2 mm) are laminated so as to overlap, and 1 kg of weight is placed on top of each other, heated and cured at 140 ° C. for 1 hour, and a fiber-reinforced resin molded product and metal A hybrid member was obtained and used as a test piece.

(Comparative Example 1)
STR120N131-KA6N (manufactured by Mitsubishi Rayon Co., Ltd.) is used as a fiber reinforced resin material. Two 25 cm square test pieces with a thickness of 2 mm are cut out and stacked, and press molded to obtain a fiber reinforced resin molded product on a 30 cm square plate. It was. The average value P of the fiber content of the obtained molded product was 44.2%, and the coefficient of variation Q was 47.1%.

  A hybrid member of a fiber reinforced resin molded product and a metal was obtained in the same manner as in Example 1 to obtain a test piece.

As is clear from Table 1, Example 1 had high shear strength and good fracture morphology.

  Since the fiber reinforced resin molded article and metal hybrid structure member of the present invention are excellent in adhesive strength and fracture mode, they can be used in a wide range of fields such as aircraft members, automobile members, and sports equipment.

Claims (8)

A fiber-reinforced resin molded body and metal hybrid structure member, in which the following fiber-reinforced resin molded body (1) and metal are integrated via an adhesive (2).
<Fiber reinforced resin molding (1)>
A fiber-reinforced resin molded body containing a fiber bundle in which a plurality of reinforcing fibers are bundled and a matrix resin, and the reinforcing fiber per unit section of 0.1 mm square on the cut surface in the thickness direction of the fiber-reinforced resin molded body The variation coefficient of the content rate is 40% or less.
<Adhesive (2)>
An adhesive having an elastic modulus of 2 GPa or less.   The hybrid structural member according to claim 1, wherein the hybrid structural member has a tensile bond shear strength at 23 ° C. of 14 MPa or more.   The hybrid structure member according to claim 1 or 2, wherein an average fiber length of reinforcing fibers in the fiber-reinforced resin molded body is 5 to 100 mm.   The hybrid structural member according to any one of claims 1 to 3, wherein a coefficient of variation of the reinforcing fiber content per unit section of 0.1 mm square is 10% or less.   The hybrid structural member according to claim 1, wherein the reinforcing fiber is a carbon fiber.   The hybrid structure member according to claim 1, wherein the adhesive has a thickness of 0.1 to 4 mm.   The hybrid structure member according to claim 1, wherein the adhesive has a thickness of 0.1 to 1 mm.   The hybrid structure member according to claim 1, wherein the adhesive is an epoxy adhesive.