JP2006044260A - Integrated structural member and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an integrated structural member causing no warpage or release, and its manufacturing method. <P>SOLUTION: In the integrated structural member constituted by bonding a first member containing reinforcing fibers and a matrix resin composition and a second member, the vertical adhesive strength of the bonded surface of the first and second members is 6 MPa or above at 25°C, the flexural modulus of elasticity based on ASTM D790 of the first member is 20 GPa or above and the coefficient CI of linear expansion of the first member is 4×10<SP>-5</SP>or below. The absolute value of a value Cb/Cs calculated by dividing the large value Cb in the coefficient CI of linear expansion of the first member and the coefficient CII of linear expansion of the second member by the smaller value Cs in them is 50 or below. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an integrated structure member obtained by bonding a first member comprising a reinforcing fiber and a matrix resin composition and a second member, and a method for producing the same, and is firmly bonded, and Provided is an integrated structural member with less warping.

  Fiber reinforced plastics are excellent in moldability, thin wall, light weight, high rigidity, productivity, and economical efficiency. Electrical / electronic equipment parts, automotive equipment parts, personal computers, OA equipment, AV equipment, mobile phones, telephones, facsimiles, home appliances. It is frequently used for parts and casings of electrical and electronic equipment such as toy supplies. However, for example, fiber reinforced plastic plates in a form in which long fiber groups of reinforcing fibers are arranged in layers are materials that are particularly thin-walled, lightweight, and highly rigid. It was unsuitable for easy production.

  On the other hand, metal materials such as Mg alloys can be used for electronic devices such as personal computers, mobile phones, personal digital assistants, office automation equipment, automobiles, building materials, etc. It came to be used. However, even when trying to use metal materials for all parts, Mg alloy has a problem that the specific gravity is larger than fiber reinforced plastic and a sufficient weight reduction effect cannot be obtained, and the cost is increased.

  On the other hand, injection molding is a molded product that is easy to form in a complicated shape and excellent in mass productivity. Therefore, there is a demand for a technique for integrally joining a composite material such as a fiber reinforced plastic plate or a metal plate with another injection molded product or the like. Such structural members made by integrating members made of different materials are integrated in the case where there is a difference in thermal expansion coefficient and contraction rate between the members to be bonded as well as the adhesiveness at the joint. There is a problem in that the structural member is warped, or in some cases, the joint surface is peeled off.

As an integration method for such a problem, a method in which a previously molded member is joined using an adhesive has been generally employed. For example, Patent Document 1 discloses an electronic device casing in which a metal frame and an injection-molded rib are bonded with an epoxy resin-based paint. However, the method using an adhesive disclosed in Patent Document 1 requires an adhesive preparation step and an application step, and thus it is difficult to reduce production costs.
JP 2001-298277 A

  Accordingly, an object of the present invention is to provide an integrated structure member that eliminates the problems of the prior art and does not cause warping or peeling.

In order to solve the above-described problems, an integrated structural member according to the present invention is an integrated structural member formed by joining a first member comprising a reinforcing fiber and a matrix resin composition, and a second member. In the above, the vertical adhesive strength at the joint surface between the first member and the second member is 6 MPa or more at 25 ° C., the bending elastic modulus of the first member is 20 GPa or more, and the line of the second member A value obtained by dividing the larger value Cb between the linear expansion coefficient CI of the first member and the linear expansion coefficient CII of the second member by the smaller value Cs and having an expansion coefficient CII of 4 × 10 ⁻⁵ or less. The absolute value of Cb / Cs is 50 or less.

  In addition, the integrated structural member according to the present invention is an integrated structure in which a first member comprising a reinforcing fiber and a matrix resin composition and a second member are joined via a thermoplastic resin layer. In the structural member, the vertical adhesive strength at the joint surface between the first member and the second member is 6 MPa or more at 25 ° C., and the first member and the second member of the integrated structural member are integrated. In the substantially flat portion, the absolute value of CII / CI calculated from the linear expansion coefficient CI of the first member and the linear expansion coefficient CII of the second member is 0.1 to 10, It consists of what to do.

  In addition, the manufacturing method of the integrated structure member according to the present invention includes joining the first member and the second member by heat welding, vibration welding, ultrasonic welding, laser welding, insert injection molding, outsert injection. By performing at least one method selected from molding, the above-described integrated structure member is obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the integrated structure member without the curvature and peeling joined with the 2nd member can be easily obtained using the 1st member.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
The integrated structural member according to the present invention has a first member as one of its constituent elements. The first member comprises reinforcing fibers and a matrix resin composition.

  Examples of reinforcing fibers include metal fibers such as aluminum, brass, and stainless steel, polyacrylonitrile-based, rayon-based, lignin-based, pitch-based carbon fibers, graphite fibers, insulating fibers such as glass, aramid, PBO, Examples thereof include organic fibers such as polyphenylene sulfide, polyester, acrylic, nylon, and polyethylene, and inorganic fibers such as silicon carbide and silicon nitride. Moreover, the surface treatment may be given to these fibers. Examples of the surface treatment include a treatment with a coupling agent, a treatment with a sizing agent, and an adhesion treatment of an additive in addition to a treatment for depositing a metal as a conductor. Moreover, these reinforcing fibers may be used individually by 1 type, and may use 2 or more types together. Among these, carbon fiber, particularly polyacrylonitrile-based carbon fiber is preferably used from the viewpoint of the balance of specific strength, specific rigidity, light weight, and conductivity, and in particular, at a low cost.

  Moreover, as a form of a reinforced fiber, what has an average length of 10 mm or more is laminated | stacked and arrange | positioned at a layer form is preferable when expressing the reinforcement effect of a reinforced fiber efficiently. As the form of the reinforcing fiber layer, a form in which cloths, filaments, blades, filament bundles, spun yarns and the like are arranged in one direction can be suitably used. In the case of stacking layers in a form aligned in one direction, it is preferable to stack the layers while shifting the direction for each layer in order to reduce the strength anisotropy of the stacked body. Moreover, the form of these layers may be used individually by 1 type, or may use 2 or more types together.

  As a ratio of the reinforcing fiber with respect to the 1st member used by this invention, 5-75 volume% is preferable from a viewpoint of a moldability and a dynamic characteristic, and 10-65 volume% is more preferable.

  The first member used in the present invention includes a thermosetting resin composition layer in which reinforcing fibers are arranged in a thermosetting matrix resin, and a thermoplastic resin formed on at least a part of the thermosetting resin composition layer. It is preferable that it is the 1st member which consists of a composition layer.

  Use of a thermosetting resin is preferable for obtaining mechanical properties. Examples of thermosetting resins include unsaturated polyesters, vinyl esters, epoxies, phenols (resol type), urea melamine, polyimides, copolymers, modified products, or resins blended with two or more. can do. Among these, those containing at least an epoxy resin are preferable from the viewpoint of the mechanical properties of the first member. In order to improve impact resistance, an elastomer or a rubber component may be added to the thermosetting resin composition.

  The thermoplastic resin composition layer is preferable when integrated with the second member through the thermoplastic resin composition layer. Examples of the thermoplastic resin constituting the thermoplastic resin composition layer include polyamide resin, polyester resin, polycarbonate resin, EVA resin (ethylene-vinyl acetate copolymer resin), styrene resin, and PPS (polyphenylene sulfide). Examples thereof include resins. These modified products may also be used. These thermoplastic resins may be used alone or in combination of two or more of these copolymers or blend polymers.

  Moreover, according to a use etc., you may contain another filler and additive. For example, inorganic fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration damping agents, antibacterial agents, insect repellents, deodorants, anti-coloring agents, heat stabilizers, release agents , Antistatic agents, plasticizers, lubricants, colorants, pigments, dyes, foaming agents, antifoaming agents, coupling agents and the like.

  In addition, it is important for use as a structural member that the vertical adhesive strength at the joint surface between the first member and the second member is 6 MPa or more at 25 ° C., more preferably 8 MPa or more, and still more preferably 10 MPa or more. A normal adhesive exhibits only an adhesive strength of about 10 MPa, and if it is 12 MPa or more, it is considered sufficient adhesive strength. Although there is no restriction | limiting in particular in the upper limit of perpendicular | vertical adhesive strength, if it is 30 Mpa or less, it can fully use for practical use.

  As shown in FIG. 2, the vertical adhesive strength of the sample 5 for evaluating the vertical adhesive strength is 10 mm × 10 mm from the part where the first member 7 and the second member 6 are joined from the integrated structural member. Cut out with. At this time, if a mechanical connection such as a fitting or bolt is applied, remove it beforehand or do not use such a part for the test. Next, as shown in FIG. 3, the vertical adhesive strength evaluation sample 9 (adhesion surface: 10) cut out to a predetermined size is fixed to the tension jigs 8 a and 8 b of the measuring apparatus. As the measuring apparatus, an “Instron” (registered trademark) 5565 type universal material testing machine (manufactured by Instron Japan Co., Ltd.) is used. For fixing the sample, if the molded product can be gripped by Instron's chuck, hold it in the chuck as it is and perform a tensile test, but if it cannot be gripped, apply an adhesive (ThreeBond 1784, manufactured by ThreeBond Co., Ltd.) to the molded body. , 23 ± 5 ° C. and 50 ± 5% RH for 4 hours, and may be bonded to the jig. The maximum load is divided by the bonding area from the result of the tensile test to obtain the vertical bonding strength (MPa).

  Moreover, in the meaning which raises adhesion | attachment by an anchor effect, it is preferable that the thermosetting resin composition layer and the thermoplastic resin composition layer have the uneven | corrugated shape in the interface of these layers, and are integrated. Furthermore, it is preferable that both the thermosetting resin composition layer and the thermoplastic resin composition layer have reinforcing fibers embedded in at least a part thereof. By setting it as this aspect, a weak part is not left. Further, in the vicinity of the interface between the two layers, the adhesion between the thermosetting resin composition and the thermoplastic resin composition can be made stronger by mediating reinforcing fibers, and furthermore, the same fibers When the thermosetting resin composition layer and the thermoplastic resin composition layer are buried in both layers, the adhesion interface is reinforced by the effect of skewering, so that strong adhesion can be obtained.

  The maximum thickness Tpf of the region where the group of reinforcing fibers embedded in the thermoplastic resin composition layer is preferably 10 μm or more, more preferably 20 μm or more, and further preferably 40 μm or more. By doing so, a stronger bond can be obtained. This maximum thickness Tpf is embedded in the thermoplastic resin composition layer as viewed from the surface (2 in FIG. 1) of the thermoplastic resin composition layer (1a in FIG. 1) in the thickness direction of the thermoplastic resin composition layer. Of the reinforcing fibers 3 that are closest to the surface (3-out in FIG. 1) and the portion where the penetration depth from the surface of the thermoplastic resin composition layer is the largest is buried in the thermoplastic resin composition layer. It is defined as the distance in the thickness direction of the reinforcing fibers that are in contact with each other or that are farthest from the surface (3-in in FIG. 1). The maximum thickness Tpf can be measured using a SEM observation photograph or a TEM observation photograph of the cross section of the fiber reinforced composite material. If the maximum thickness Tpf is 1,000 μm at the maximum, sufficient bonding strength can be obtained. Mao. In FIG. 1, 1b has shown the thermosetting resin composition layer.

  From the viewpoint of using this first member as at least a part of the integrated structural member, it is assumed that a large load is applied. Further, since it is integrated with the second member, if the rigidity is not high, warping may occur due to distortion or the like when the second member is integrated. Therefore, in order to withstand the use, it is important that the flexural modulus is 20 GPa or more. When the first member has an anisotropy of the lip elastic modulus in the plane, the minimum value is evaluated. Further details of the measurement method will be described later in Examples.

Also, it is important to reduce the warpage and peeling of the integrated structural member that the second member has good dimensional stability and that the first member and the second member have the same dimensional stability. is there. Therefore, the linear expansion coefficient CII of the second member is 4 × 10 ⁻⁵ or less, and the larger value Cb of the linear expansion coefficient CI of the first member and the linear expansion coefficient CII of the second member is small. It is important that the absolute value of the value Cb / Cs divided by the other value Cs is 50 or less. When the linear expansion coefficient CII of the second member is 4 × 10 ⁻⁵ or more, since the shrinkage is large, warpage or peeling occurs when the integrated member is formed. The lower limit of the linear expansion coefficient is not particularly limited, but 1 × 10 ⁻⁷ or more is a practical lower limit. When the absolute value of the value Cb / Cs obtained by dividing the larger value Cb of the linear expansion coefficient CI of the first member and the linear expansion coefficient CII of the second member by the smaller value Cs is larger than 50, the shrinkage occurs. Warpage or peeling occurs due to the difference of

  In the present invention, when the coefficient of linear expansion of a member is simply referred to as “CI” or “CII”, “max” and “min” are not attached), in the case of the first member, the fiber orientation direction (D ) And the second member is measured in the same direction as the fiber orientation direction (D) on the outermost surface of the first member. Here, the fiber orientation direction (D) on the outermost surface is determined as follows. First, the surface of the first member is observed with an optical microscope or SEM (scanning electron microscope). At this time, in order to clarify the observation, it is possible to polish the surface to such an extent that the orientation direction of the fibers does not change. Next, a reference straight line L is set, the orientation angle of the fiber axis of the reinforcing fiber observed with respect to the straight line L is measured at n = 200, and the average is defined as the fiber orientation angle of the outermost surface of the first member. The orientation angle direction is the fiber orientation direction of the outermost surface of the first member.

  The linear expansion coefficient can be measured based on ISO 11359-2. 4 cut out with respect to the fiber orientation direction of the outermost surface of the first member at a portion randomly selected from the substantially flat surface where the first member and the second member of the integrated structural member are integrated. Prepare a test piece of book. As for the cutout position of the test piece, portions where shapes such as ribs, hinges, and concavo-convex portions are intentionally avoided should be avoided as much as possible. The first member and the second member are separated from each other from these test pieces, and the respective linear expansion coefficients with respect to the fiber orientation direction on the outermost surface of the first member are measured. The linear expansion coefficient in the first member is defined as CI, and the linear expansion coefficient in the second member is defined as CII. In addition, although there is no restriction | limiting in particular in a measurement temperature range, 30-200 degreeC can be illustrated as a preferable range from the viewpoint of the environment where an integrated structural member is used.

  Further, as another aspect of the dimensional stability of the first member and the second member being substantially the same, the substantially planar portion in which the first member and the second member of the integrated structure member are integrated. It is also important that the absolute value of CII / CI calculated from the linear expansion coefficient CI of the first member and the linear expansion coefficient CII of the second member is 0.1 to 10.

  Further, from the viewpoint of suppressing twisting of the integrated structural member depending on the use environment, the ratio between the maximum linear expansion coefficient CIImax in the surface direction and the minimum linear expansion coefficient CIImin of the second member, CIImax / CIImin is 1 to 3 It is preferable that it is, More preferably, it is 1-2, More preferably, it is 1-1.5.

  The linear expansion coefficient is measured based on ISO 11359-2. For four parts randomly selected from the second member, prepare four test pieces cut at different angles such as 0 degree, 45 degrees, 90 degrees, and 135 degrees with respect to the longitudinal direction of the member. To do. As for the cutout position of the test piece, portions where shapes such as ribs, hinges, and concavo-convex portions are intentionally avoided should be avoided as much as possible. In these test pieces, the maximum value is defined as the maximum linear expansion coefficient CIimax, and the minimum value is defined as the minimum linear expansion coefficient CIimin. In addition, although there is no restriction | limiting in particular in a measurement temperature range, 30-200 degreeC can be illustrated as a preferable range from a viewpoint of the environment where a molded article is used.

The same can be said for the linear expansion coefficient CI of the first member.
The upper limit of the linear expansion coefficient CII of the second member is not particularly limited, but is preferably 1 × 10 ⁻⁴ or less from the viewpoint of dimensional stability of the integrated structural member.

  The second member is preferably a member containing a thermoplastic resin composition from the viewpoint of processability.

Moreover, it is preferable that it is an injection molded product from a viewpoint of productivity, and it is preferable that the maximum mold shrinkage is 1% or less from the viewpoint of dimensional stability. More preferably, it is 0.7% or less, More preferably, it is 0.4% or less. The maximum molding shrinkage ratio is measured by measuring four dimensions R of an arbitrary part from the injection mold and measuring four actual dimensions r of the second member corresponding thereto. The molding shrinkage represented by r / R × 100 (%) is measured, and the maximum value is defined as the maximum molding shrinkage.
Further, a fiber reinforced system is preferable from the viewpoint of mechanical properties. Specifically, it is a thermoplastic resin composition comprising (A) 40 to 95% by weight of a thermoplastic resin and (B) 5 to 60% by weight of a reinforcing fiber, in order to have high mechanical properties and a low coefficient of linear expansion. The number average fiber length is preferably 0.3 mm or more.

  Examples of the thermoplastic resin (A) used for the second member include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PENp), and liquid crystal polyester. Polyester, polyethylene (PE), polypropylene (PP), polybutylene and other polyolefins, styrenic resins, polyoxymethylene (POM), polyamide (PA), polycarbonate (PC), polymethylene methacrylate (PMMA) , Polyvinyl chloride (PVC), polyphenylene sulfide (PPS), polyphenylene ether (PPE), modified PPE, polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polysulfone (PSU), modified PSU, polyethersulfone, polyketone (PK), polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyarylate (PAR), polyethernitrile (PEN) ), Fluororesins such as phenolic resins, phenoxy resins, polytetrafluoroethylene, thermoplastic elastomers such as polybutadiene, polyisoprene, and fluorine, copolymers, modified products, and blends of two or more It may be a resin. In particular, PPS resin is used from the viewpoint of heat resistance and chemical resistance, polycarbonate resin and styrene resin are used from the viewpoint of molded product appearance and dimensional stability, and polyamide resin is used from the viewpoint of strength and impact resistance of the molded product. More preferably used.

  Further, other elastomers or rubber components may be added to improve impact resistance. Moreover, according to a use etc., you may contain another filler and additive in the range which does not impair the objective of this invention. For example, inorganic fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration damping agents, antibacterial agents, insect repellents, deodorants, anti-coloring agents, heat stabilizers, release agents , Antistatic agents, plasticizers, lubricants, colorants, pigments, dyes, foaming agents, antifoaming agents, coupling agents and the like.

  The reinforcing fiber used in the second member can be selected based on the same idea as the reinforcing fiber in the first member. However, when the second member is formed by injection molding, it is preferable that the reinforcing fibers are short fibers and are uniformly dispersed in the thermoplastic resin composition. As a compounding ratio of the reinforcing fiber in this case, when the reinforcing fiber is a carbon fiber, it is 5 to 60 weights with respect to the first member of the second member from the viewpoint of the balance between moldability, strength, and lightness. % Is preferred, more preferably 15 to 55% by weight.

Further, the linear expansion coefficient CI of the first member has a maximum value CImax and a minimum value C
When β is set, CImax / CImin is preferably 1 to 3. More preferably, it is 1-2.5, More preferably, it is 1-2. When the absolute value of CImax / CImin is larger than 3, the first member becomes a material having an anisotropic linear expansion coefficient, which may cause warpage or peeling of the integrated structural member.

  As a method of manufacturing the integrated molded product by joining the first member and the second member, the process temperature is equal to or higher than the melting point of the thermoplastic resin constituting the thermoplastic resin composition layer in the first member. For example, the second member is bonded and then cooled to join the fiber-reinforced composite material and another structural material. Examples of the technique for melting and bonding the thermoplastic resin include thermal welding, vibration welding, ultrasonic welding, laser welding, insert injection molding, and outsert injection molding.

  Moreover, it is also preferable that the integration of the first member and the second member is performed by using fitting or fitting together in an auxiliary manner.

  The shape of the integrated structural member of the present invention may include a curved surface, a rib, a hinge, a boss, a hollow portion, and the like. Further, the molded product may be subjected to surface decoration treatment by plating, painting, vapor deposition, insert, stamping, laser irradiation, or the like.

  The integrated structural member of the present invention can be suitably used for parts, members or casings of electric / electronic devices, OA devices, home appliances, automobiles or building materials.

[Evaluation / Measurement Method]
(1) Flexural modulus The first member used in each example was evaluated based on ISO 14125. Four test pieces were prepared by cutting out from the substantially planar portion of the first member at different angles of 0 degrees, 45 degrees, 90 degrees, and 135 degrees with respect to the longitudinal direction of the first member. As for the cutout position of the test piece, portions where shapes such as ribs, hinges, and concavo-convex portions are intentionally avoided should be avoided as much as possible. The minimum value of the flexural modulus obtained from these test pieces was adopted as the flexural modulus referred to herein.

(2) Linear expansion coefficient The first member and the second member used in each example were evaluated based on ISO 11359-2. The measurement temperature range was 30 to 200 ° C. If the first member and the second member can be evaluated separately in advance, they are evaluated in advance. When evaluating from an integrally molded product, a part where the rib part, hinge part, uneven part, etc. are intentionally attached from the substantially flat part of the first member and the second member of the integrally molded part Avoid as much as possible, and if the above part is included, cut and remove these to cut out the test piece.

  The first member was measured in the fiber orientation direction (D) on the outermost surface of the member, and the second member was measured in the same direction as the fiber orientation direction (D) on the outermost surface of the first member. Here, the fiber orientation direction (D) on the outermost surface was determined as follows. First, the surface is polished, the first member surface is observed with an optical microscope, a reference straight line L is set, and the orientation angle of the fiber axis of the reinforcing fiber observed with respect to the straight line L is n = 200. The average was taken as the fiber orientation angle on the outermost surface of the first member, and the orientation angle direction was taken as the fiber orientation direction on the outermost surface of the first member. In addition, the maximum value and the minimum value of the linear expansion coefficient are four cut out at different angles of 0 degrees, 45 degrees, 90 degrees, and 135 degrees with respect to the longitudinal direction of the first member and the second member. The test piece was measured, and the largest one of these was the maximum value of the linear expansion coefficient, and the smallest one was the minimum value of the linear expansion coefficient. In this example, the first member and the second member were evaluated in advance.

(3) Tpf
The cross section of the first member was observed with a TEM and measured as follows. In the thickness direction of the thermoplastic resin composition layer of the first member, as seen from the surface (2 in FIG. 1) of the thermoplastic resin composition layer (1a in FIG. 1), it is buried in the thermoplastic resin composition layer. Among the reinforcing fibers that are closest to the surface (3-out in FIG. 1) and the portion where the penetration depth from the surface of the thermoplastic resin composition layer is the largest, it is buried in the thermoplastic resin composition layer. Or the distance of the thickness direction with the thing (3-in in FIG. 1) farthest from the surface among the reinforcing fibers which are in contact is measured as Tpf.

(4) Vertical Adhesive Strength As shown in FIG. 2, from an integrally molded product, the vertical adhesive strength evaluation sample 5 is 10 mm × 10 mm from the portion where the first member 7 and the second member 6 are joined. Cut out in size. Next, as shown in FIG. 3, a sample 9 (adhesive surface: 10) for vertical adhesive strength evaluation cut out to a predetermined size was fixed to the tension jigs 8a and 8b of the measuring apparatus. As the measuring device, “Instron” (registered trademark) 5565 type universal material testing machine (manufactured by Instron Japan Co., Ltd.) was used. For fixing the sample, if the molded product can be held by Instron's chuck, the sample is held in the chuck as it is and a tensile test is performed. If the sample cannot be held, an adhesive (ThreeBond 1782, manufactured by ThreeBond Co., Ltd.) is applied , 23 ± 5 ° C. and 50 ± 5% RH for 4 hours, and may be bonded to the jig.

  The tensile test was performed at an ambient temperature of 25 ° C. in a test chamber in which the ambient temperature can be adjusted. Before starting the test, keep the test piece in the test chamber free from the tensile test load for at least 5 minutes, and place a thermocouple on the test piece to confirm that it is equivalent to the ambient temperature. After that, a tensile test was performed.

  The tensile test was conducted by pulling from the bonding surface of both at 90 ° direction (tensile direction arrows 11a and 11b) at a pulling speed of 1.27 mm / min, and the value obtained by dividing the maximum load by the bonding area (vertical bonding strength ( (Unit: MPa). The number of samples was n = 5.

(5) Weight average fiber length A part of the second member was cut out, and the matrix resin (polyamide 6 resin) was sufficiently dissolved with an organic solvent for dissolving the matrix resin (in this example, formic acid for dissolving the polyamide 6 resin). Thereafter, the reinforcing fibers were separated by filtration. At least 400 separated reinforcing fibers were randomly extracted, the length was measured with an optical microscope up to 1 μm unit, and the weight average fiber length was calculated from the following formula.
Weight average fiber length = Σ (Li × Wi / 100)
Li: measured fiber length (i = 1, 2, 3,... N)
Wi: Fiber weight fraction of fiber length Li

Example 1 (Plate-like integrated molded product)
(First member)
A prepreg P6053-12 using “Torayca” manufactured by Toray Industries, Inc. was cut to a predetermined size to produce a flat molded pair. First, six prepregs are laminated on a female mold so that the longitudinal direction of the rectangular bottom is 0 ° and the fiber direction is 45 °, −45 °, 90 °, 90 °, −45 °, 45 ° from the top. did. From the top of the last laminated prepreg, as a thermoplastic resin composition layer, Toray Industries, Ltd., terpolymer polyamide resin CM4000 (nylon 6/66/610, melting point 150 ° C., solubility parameter δ (SP value) 13. 3) Nonwoven fabrics having a width of 1000 mm (weight per unit area: 30 g / m ² , single fiber fineness: 0.2 tex) cut into the same size as the molded body were stacked and laminated. Next, a male mold was set and press molding was performed. The thermoplastic resin composition layer was melted by preheating at 160 ° C. for 5 minutes in a press molding machine, and then cured by heating at 150 ° C. for 30 minutes while applying a pressure of 6 MPa. After the curing, the product was cooled at room temperature and demolded to obtain a first member having an average thickness of 0.7 mm. The maximum thickness Tpf of the thermoplastic resin composition layer of the obtained first member is 25 μm, the flexural modulus is 30 MPa, the density is 1.56 g / cm ³ , the linear expansion coefficient CI is 3.3 × 10 ⁻⁶ , The absolute value of the maximum value CImax / minimum value CImin of the expansion coefficient was 1.8.

(Second member)
The same first member as above was used as the second member.

(Integrated)
The first member and the second member are heated with a hot plate at 160 ° C. for 3 minutes, and then the surfaces having the thermoplastic resin composition layers are joined surfaces, and the fiber orientation directions of the outermost layers are the same. Then, they were laminated together by holding at a pressure of 20 MPa for 2 minutes to obtain a plate-like integrated molded product. Attempts were made to evaluate the vertical adhesive strength of the obtained integrally molded product. At 6 MPa, the fixed part by the adhesive between the sample and the jig peeled off before the joint part peeled off. Evaluated as being. The absolute value of Cb / Cs was 1.

Example 2 (electronic equipment casing)
(First member)
The first member obtained in the same manner as in Example 1 was also used in this example.

(Second member / integration)
The first member is inserted into an injection mold, and the first member has a thermoplastic resin composition layer. As a second member, a long fiber pellet TLP1146 (polyamide) manufactured by Toray Industries, Inc. A resin matrix and a carbon fiber content of 20% by weight) were molded and integrated by injection molding to obtain an electronic device casing as shown in FIG. In FIG. 4, a personal computer casing 12 including a first member 13 and a second member 14 is illustrated. The linear expansion coefficient of the second member was 1.4 × 10 ⁻⁵ , the absolute value of CIImax / CIImin was 1.9, and the weight average fiber length was 0.6 mm. The maximum molding shrinkage of the second member was 0.2%. The injection molding machine uses J350EIII manufactured by Nippon Steel, Ltd., and the injection molding is screw rotation 60 rpm, cylinder temperature 280 ° C., injection speed 90 mm / sec, injection pressure 200 MPa, back pressure 0.5 MPa, mold temperature 55 Performed at ° C. Attempts were made to evaluate the vertical adhesive strength of the obtained integrally molded product. At 6 MPa, the fixed part by the adhesive between the sample and the jig peeled off before the joint part peeled off. Evaluated as being. The absolute value of CII / CI was 6.7.

The maximum thickness Tpf in the 1st member used by this invention is typically illustrated. It is a schematic diagram of the sample for vertical adhesive strength evaluation of the integrated structural member of this invention. It is a schematic diagram of sample installation in the vertical adhesive strength evaluation of the integrated structural member of the present invention. It is a perspective view of the electronic device housing | casing which is one aspect | mode (Example 2) of the integrated structure member of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a Thermoplastic resin composition layer 1b Thermosetting resin composition layer 2 Surface of 1st member 3 Fiber reinforcement 3-in Reinforcing fiber which is buried in or touches the thermoplastic resin composition layer and which is farthest from the surface 3-out Reinforcing fiber closest to the surface embedded in the thermoplastic resin composition layer 4 Interface between the thermosetting resin composition layer of the first member and the thermoplastic resin composition layer 5 Sample for vertical adhesive strength evaluation 6 Second member 7 First member 8a Tensile jig 8b Tensile jig 9 Sample for vertical adhesive strength evaluation 10 Adhesive surface 11a Tensile direction arrow 11b Tensile direction arrow 12 PC housing 13 First member 14 Second member

Claims (16)

In the integrated structure member formed by joining the first member comprising the reinforcing fiber and the matrix resin composition and the second member, in the joint surface between the first member and the second member The vertical adhesive strength is 6 MPa or more at 25 ° C., the flexural modulus of the first member is 20 GPa or more, the linear expansion coefficient CII of the second member is 4 × 10 ⁻⁵ or less, and the first member The absolute value of the value Cb / Cs obtained by dividing the larger value Cb of the linear expansion coefficient CI of the second member and the linear expansion coefficient CII of the second member by the smaller value Cs is 50 or less. Structural member.   In an integrated structure member in which a first member comprising a reinforcing fiber and a matrix resin composition and a second member are joined via a thermoplastic resin layer, the first member and the first member The vertical adhesive strength at the joint surface with the second member is 6 MPa or more at 25 ° C., and the first member An integral structure member characterized in that the absolute value of CII / CI calculated from the linear expansion coefficient CI of the second member and the linear expansion coefficient CII of the second member is 0.1-10.   The ratio between the maximum linear expansion coefficient CIImax and the minimum linear expansion coefficient CIimin in the surface direction of the second member, and the absolute value of CIImax / CIImin is in the range of 1 to 3. Integrated structural member.   The linear expansion coefficient CI of the first member has a maximum value CImax and a minimum value CImin, and CImax / CImin is in the range of 1 to 3 according to any one of claims 1 to 3. Structural member. The integrated structural member according to claim 3 or 4, wherein the second member has a maximum coefficient of linear expansion of 1 x ^10-4 or less.   The integrated structure member according to claim 1, wherein the second member is a member containing a thermoplastic resin composition.   The integrated structural member according to claim 6, wherein the second member containing the thermoplastic resin composition is integrated by injection molding.   The integrated structure member according to claim 7, wherein the maximum molding shrinkage ratio of the second member containing the thermoplastic resin composition is 1% or less.   The second member is a thermoplastic resin composition comprising (A) 40 to 95% by weight of a thermoplastic resin and (B) 5 to 60% by weight of a reinforcing fiber, and the weight average fiber length is 0.3 mm or more. The integrated structural member according to any one of claims 6 to 8.   The first member includes a thermosetting resin composition layer in which reinforcing fibers are arranged in a thermosetting matrix resin, and a thermoplastic resin composition layer formed on at least a part of the thermosetting resin composition layer. The integrated structural member according to claim 1, which is a first member comprising:   The first member includes a thermosetting resin composition layer, a thermoplastic resin composition layer, and reinforcing fibers, and the thermosetting resin composition layer and the thermoplastic resin composition layer are formed of these layers. A first member that is integrated with an uneven shape at the interface, and in which both the thermosetting resin composition layer and the thermoplastic resin composition layer are embedded with reinforcing fibers at least partially. The integrated structural member according to claim 1, wherein   The integrated structure member according to claim 10 or 11, wherein in the thermoplastic resin composition layer, a maximum thickness Tpf of a region where the reinforcing fibers are present is 10 µm or more.   The integrated structural member according to claim 1, wherein the reinforcing fibers are carbon fibers.   The integrated structure member according to claim 10, wherein the thermosetting resin composition layer contains an epoxy resin.   The integrated structural member according to any one of claims 1 to 14, wherein the integrated structural member is used for any one of a part, a member, or a casing of an electric / electronic device, an OA device, a home appliance, an automobile, or a building material.   By joining the first member and the second member by at least one method selected from thermal welding, vibration welding, ultrasonic welding, laser welding, insert injection molding, outsert injection molding, A method for producing an integrated structural member, comprising the integrated structural member according to claim 1.

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