Composite molded product, method for manufacturing composite molded product, and grooved resin molded product

Abstract

The present invention provides a composite molded product that can further enhance the strength when joined with other molded products, even when the resin molded product does not contain inorganic fillers such as glass fibers. [Solution] A composite molded product comprising a member 4 having a joint and a molded product 5 made of resin A integrated at the joint, wherein the member 4 has a plurality of grooves 3 at the joint, the grooves having a slit-shaped opening, gradually narrowing in width and extending partway to the depth, with a sharp tip and a pair of opposing groove wall surfaces connecting the tip and the opening, the groove wall surfaces being connected to voids 2 inside the member 4, the voids 2 being spherical with a diameter in the range of 1.0 to 200 μm, and the total volume of the voids 2 in the member 4 being 15 to 30% of the total volume of the member 4, a method for manufacturing a composite molded product, and a grooved resin molded product.

Description

Technical Field

[0001] The present invention relates to a composite molded product, a method for manufacturing the composite molded product, and a resin molded product with grooves for forming the composite molded product.

Background Art

[0002] In recent years, in fields such as automobiles, electrical products, and industrial equipment, in order to meet the demands for reducing carbon dioxide emissions and manufacturing costs, the movement to replace some of the metal molded products with resin molded products has been spreading. Along with this, composite molded products in which a resin molded product and a metal molded product are integrated have become widely popular. Not limited to this, composite molded products in which molded products made of the same or different materials are integrated have also become widely popular.

[0003] As a method for manufacturing a composite molded product in which one molded product and another molded product are integrated, for example, in Patent Document 1, a nanostructure is formed on the surface of one resin molded product by irradiating electromagnetic radiation, and then the other resin molded product is brought into contact with the surface and filled and molded to be integrated.

[0004] In Patent Document 2, a technique has been proposed to form a groove on the bonding surface of a first resin molded product containing glass fibers by laser, and to form a composite molded product by injection molding a second resin onto the bonding surface (FIG. 12).

Prior Art Documents

Patent Documents

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention was made to solve the above-mentioned problems, and its objective is to provide a composite molded product that can further increase the strength when joined with other molded products, even when the resin molded product does not contain inorganic fillers such as glass fibers.

[0008] Another objective of the present invention is to provide a composite molded product formed by integrating a non-resin component having internal voids with a thermoplastic resin. [Means for solving the problem]

[0009] The objective of the present invention was achieved as follows. 1) A composite molded product comprising a member having a joint and a molded product made of resin A integrated at the joint, wherein the member has a plurality of grooves at the joint, each having a slit-shaped opening, gradually narrowing in width and extending partway to the depth, and having a sharp tip, and these grooves are connected to voids within the member. A composite molded product in which the aforementioned void is spherical and has a diameter in the range of 1.0 to 200 μm. 2) A method for manufacturing a composite molded product, comprising forming a plurality of grooves in a member having a spherical void with a diameter in the range of 1.0 to 200 μm, the grooves having slit-shaped openings, gradually narrowing in width and extending partway to the depth, and having sharp tips, and then injection molding resin A into the grooves of the member. 3) The method for manufacturing a composite molded article according to 2, wherein the groove is formed by laser irradiation. 4) A grooved member having a joint, which is integrated with a molded product made of resin A at the joint to form a composite molded product, the grooved member having a plurality of grooves connected to the joint, the grooves having a slit-shaped opening, which gradually narrows in width and extends partway to the depth, and which have a sharp tip. 5) The composite molded article according to 1 to 3 above, wherein the member is made of thermoplastic resin B. 6) A composite molded article in which the difference between the decomposition temperature and melting point of the thermoplastic resin B is 250°C or less. 7) The composite molded article according to 2 and 8, wherein the total volume of the voids in the member is 15 to 30% of the total volume of the member. [Effects of the Invention]

[0010] In the composite molded product of the present invention, the presence of voids in the member allows the groove surface, which is the joint between the member and the molded product made of resin A, to connect with part or all of the voids, thereby increasing the bonding area of ​​the groove that is substantially involved in the joining. This allows for a stronger bond and acts as an anchor to suppress the fracture of the molded product, resulting in a significant increase in the strength of the composite molded product. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view showing an example before the formation of the component of the present invention. [Figure 2] This is a schematic cross-sectional view showing an example of a grooved member of the present invention. [Figure 3] This is a schematic cross-sectional view showing an example of a composite molded product of the present invention. [Figure 4] This is a schematic cross-sectional view showing an example of a member having a groove when the void of the present invention is cylindrical. [Figure 5] This is a schematic cross-sectional view showing an example of a composite molded product in which the void of the present invention is cylindrical. [Figure 6] This is a cross-sectional metallurgical photograph showing an example of a composite molded product of the present invention. [Figure 7] This is an X-ray CT image showing an example of a grooved member of the present invention. [Figure 8] This is a schematic diagram showing the angle of the groove in the component of the present invention. [Figure 9] This is a schematic diagram (grid-like) showing the groove pattern and dimensions of the member joint of the present invention. [Figure 10] This is a photograph showing the composite molded product of the present invention after it has been fractured in a tensile test. [Figure 11] It is a schematic diagram showing a tensile test of the composite molded product of the present invention. [Figure 12] It is a schematic cross-sectional view of a conventional (Prior Art Document 2) composite molded product.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention. Note that, regarding overlapping explanations, the explanations may be omitted as appropriate, but the gist of the invention is not limited.

[0013] <Composite Molded Product> The composite molded product of the present invention is a composite molded product in which a member having a groove at a joint portion is integrally formed with resin A at the joint portion, and the member has a void inside.

[0014] <Member> ≪Groove≫ A plurality of grooves are formed on the surface of the member. In the present invention, the surface of the member having the groove is used as a joint portion, and is integrated with another molded product to manufacture a composite molded product.

[0015] By providing a plurality of grooves formed on the surface of the member, the effect of the anchor is further enhanced. The plurality of grooves may be formed by folding back adjacent to each other with a single groove, or may be formed by a plurality of grooves.

[0016] The plurality of grooves may be arranged side by side like contour lines with both ends connected, may be formed in a non-intersecting striped shape, may be formed in a lattice shape where the grooves intersect, or may be formed in a polka dot shape. When the grooves are formed in a lattice shape, it may have a diamond shape.

[0017] The length of the groove is not particularly limited. When the groove is short, the shape of the opening may be square, round, or elliptical. In order to obtain the anchor effect, a longer groove is preferred.

[0018] The spacing between adjacent grooves in the present invention is preferably 0.5 to 4 times the width of the groove, that is, if the width of the groove is 200 μm, the spacing is preferably 100 μm to 800 μm, and more preferably 1 to 2 times the width of the groove, that is, if the width of the groove is 200 μm, the spacing is preferably 200 μm to 400 μm.

[0019] The spacing between adjacent grooves is preferably 200 μm or less if the groove shape is oblique grid, and more preferably 200 μm or less if it is a straight line in one direction. Furthermore, the depth of the groove is preferably 1 / 2 or more of the length in the shorter direction of the groove.

[0020] ≪Angle θ in the groove depth direction≫ Figures 2 and 8 are schematic cross-sectional views of the member of the present invention. The upper part is the joint, the direction of the arrow is perpendicular to the joint, and θ in Figure 8 is the angle in the depth direction of the groove. θ can be selected as appropriate, with 0 ≤ θ ≤ 90°. Grooves with different θ values ​​may also be used.

[0021] ≪Void≫ The component of the present invention has an internal void, and part or all of this void is connected to the joint. If the void is foamy, the material forming the component may be a foamed resin that originally has foamy spaces, or it may be a sintered metal. If the void is tubular, it may be manufactured using a mold designed to create a tubular hole in the component during molding.

[0022] In the case of a foamy material, if thermoplastic resin B is used for the component, foamy voids (hereinafter also referred to as foamy voids) may be formed during injection molding using a foaming agent or the like. Formation by a foaming agent is preferred because a high proportion of the foamy voids have a consistent shape.

[0023] The diameter of the foamy voids is in the range of 0.1 to 100 μm, preferably 1 to 80 μm. Within this range, blockage of the voids due to laser irradiation during groove formation is easily suppressed. The diameter of the foamy voids can be measured by metallurgical microscope images of the cross-sectional view of the member. If resin B is a foamed resin that originally has foamy voids, the shape of the foamy voids becomes irregular due to kneading, etc., so the diameter refers to the short axis of the foamy void. In the case of formation with a foaming agent, the shape becomes nearly spherical, so it refers to that diameter.

[0024] The proportion of the foamy voids in the present invention to the total volume of the member is preferably 15 to 30%. If it is too small, a sufficient anchoring effect may not be obtained, and if it is too large, the strength of the member may be reduced.

[0025] When the void is tubular (Figure 4), in order to penetrate to the tubular void by laser irradiation from the surface of the member, the tubular void is preferably within 0.1 mm to 2 mm from the surface of the molded product, and more preferably within 0.2 to 1.0 mm.

[0026] If the tubular void is placed at a position further from the surface than this, it becomes difficult to fill it with resin A, and it becomes difficult to obtain sufficient strength. Furthermore, it is preferable that the diameter of the tubular void is larger than the groove irradiated by the laser. If the diameter of the tubular void is smaller than the groove irradiated by the laser, the resin melted by the laser will block the tubular void, making it difficult to obtain sufficient strength.

[0027] ≪Materials of the components≫ The material of the component is not particularly limited as long as it can form grooves by laser irradiation. It may be a resin such as a thermoplastic resin or a thermosetting resin, or a non-resin such as a ceramic or metal. Examples of thermoplastic resins include polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polybutylene terephthalate (PBT), and polyacetal (POM). If the component is a crystalline thermoplastic resin, it is desirable that the difference between the melting point and the decomposition temperature under a nitrogen atmosphere be 250°C or less.

[0028] When the difference between the melting point and the decomposition temperature exceeds 250°C, melting is likely to occur before gasification by laser irradiation. Excessive melting makes it difficult to form fine grooves, and the molten resin can clog or narrow the tube section, making it difficult to process into a tubular shape.

[0029] ≪Method for forming grooves using laser irradiation≫ The grooves in the member of the present invention are obtained by irradiating the surface of the member with a laser, removing a portion of the member, and forming multiple grooves.

[0030] Laser irradiation is set based on the type of material to be irradiated and the output of the laser device, but when the component is made of resin, it is difficult to form grooves of the specified width and depth unless the appropriate amount of energy is irradiated to form the grooves, so it is preferable to perform the irradiation in multiple stages.

[0031] The angle θ of the grooves within the component can be adjusted by irradiating the joint with a laser at the same angle as θ. When resin B is used for the component, laser absorbers such as dyes and pigments can be added to resin B to improve laser absorption. Carbon black is preferred as the laser absorber.

[0032] Furthermore, if resin B is used for the component, and the presence of a carbonized layer of resin can be confirmed by Raman spectroscopy of the groove, it can be determined that the groove was formed by laser irradiation.

[0033] <Composite molded products> Figures 3 and 5 are schematic diagrams of a schematic enlarged cross-section of the composite molded product of the present invention. In Figure 3, the grooves are formed in parallel in the same direction, and the θ of each groove is the same. Figure 5 shows the case where the void is cylindrical. Figure 6 is a micrograph of the cross-section.

[0034] ≪Resin A≫ Resin A can be any type of resin. Examples include polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polybutylene terephthalate (PBT), and polyacetal (POM).

[0035] <Method for forming composite molded products> The composite molded product of the present invention is obtained by molding. Examples of molding methods include hot plate welding, press working, bonding, painting, plating, and printing, but double molding is preferred.

[0036] In double molding, the pressure applied when sealing resin A inside the mold makes it easier to fill the grooves with resin, and it is also easy to arrange the inorganic filler inside the grooves so as to surround it.

[0037] Figure 10 shows a cross-section of the joint of a composite molded product created by double molding that fractured in a tensile test, with the component and resin A side side by side. The left side shows a component with grooves formed by laser irradiation, and it can be seen that resin A on the right side has entered into the grooves of the component. [Examples]

[0038] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, measurements were performed in an atmosphere of 23°C and 50% RH.

[0039] <Example 1> The materials used in the examples are as follows: ≪Material: Resin B≫ PBT: Juranex 2002 ED3002 (manufactured by Polyplastics Co., Ltd.) Melting point 223°C, decomposition temperature 373°C PE: Hyzex 6203B (manufactured by Prime Polymer Co., Ltd.) Melting point 130°C, decomposition temperature 470°C Foaming agent: Microsphere MBF-260EVA50 (Matsumoto Oil & Fat Pharmaceutical Co., Ltd.) ≪Resin A≫ POM: Juranex M450-44CF2001 (manufactured by Polyplastics Co., Ltd.) Melting point 165°C, decomposition temperature 280°C POM + GF 25%: Juranex GH-25CF2001 (manufactured by Polyplastics Co., Ltd.) (POM containing 25% by mass of glass fiber) Melting point 165°C, decomposition temperature 279°C The decomposition temperature was measured under a nitrogen atmosphere at a heating rate of 10°C / min using a Q500 instrument manufactured by T.A. Instruments.

[0040] <Fabrication of components> <<Preparation of test specimens>> The component was fabricated in the shape of an Izod test specimen according to ASTM D256 (W12.7 × D6.4 × L63.5 mm). Resin B and a foaming agent were mixed and kneaded in a 19:1 (mass ratio), and the mixture was injection-molded into an ASTM Izod test piece mold under the following molding conditions to produce a component before groove formation. PBT: Cylinder temperature 260℃, mold temperature 80℃ PE: Cylinder temperature 200℃, mold temperature 60℃

[0041] Next, using a laser irradiation device, an 80 μm diameter laser was irradiated perpendicularly to the joint to create a 500 μm wide grid pattern, and a grooved member with a depth of 2.0 mm was fabricated. The size of the voids was 5 to 70 μm (Figure 9).

[0042] ≪Laser Irradiation Conditions≫ Laser wavelength: 1064nm Laser irradiation diameter: 80 μm Laser Marker: Keyence MD-X1520 Laser output: 22.5W Irradiation speed: 20mm / s

[0043] <Manufacturing of composite molded products> The test specimens prepared as described above were double-molded using resin A with an ASTM test specimen mold under the conditions of a cylinder temperature of 190°C and a mold temperature of 80°C to produce an ASTM D790 bending test specimen (12.7 × 6.4 × 127 mm) as shown in Figure 11. The cross-sectional area of ​​the joint was 81.3 mm². 2 It measures (12.7 × 6.4 mm).

[0044] <Measuring joint strength> The tensile fracture strength of the prepared composite molded product samples was measured using a universal testing machine to determine the ASTM bending strength, and the tensile stress was calculated from the cross-sectional area of ​​the joint. The results are shown in Table 1. Destruction speed: 10 mm / min / Testing machine: Shimadzu Corporation universal testing machine AG-20kNXDplus

[0045] <Foaming ratio> The foaming ratio was calculated by dividing the mass of the component before groove formation, made with a composition without foaming agent, by the mass of the component before groove formation, made with a composition with foaming agent, and multiplying the result by 100.

[0046] <Volume of voids> The volume of the voids was calculated by subtracting the mass of the member before groove formation (made with a foaming agent-added composition) from the mass of the member before groove formation (made with a foaming agent-added composition), dividing this by the mass of the member before groove formation (made with a foaming agent-added composition), and multiplying by 100.

[0047] [Table 1]

[0048] Table 1 shows that the void-containing member of the present invention exhibits improved bonding strength compared to the non-void-containing member. [Explanation of Symbols]

[0049] 1. Member before forming the groove 2 void 3 grooves 4 components 5 Resin A 6 Composite molded products

Claims

1. A composite molded product comprising a member having a joint and a molded product made of resin A integrated at the joint, wherein the member has a plurality of grooves at the joint, each having a slit-shaped opening, gradually narrowing in width and extending partway to the depth, with a sharp tip and a pair of opposing groove wall surfaces connecting the tip and the opening, and the groove wall surfaces are connected to a void inside the member. The aforementioned void is spherical and has a diameter in the range of 1.0 to 200 μm. A composite molded product in which the total volume of the voids in the member is 15 to 30% of the total volume of the member.

2. A method for manufacturing a composite molded product, comprising forming a plurality of grooves in a member having spherical voids with a diameter in the range of 1.0 to 200 μm inside, wherein the total volume of the voids is 15 to 30% of the total volume, and the grooves have slit-shaped openings that gradually narrow in width and extend partway to the depth, with a sharp tip and a pair of opposing groove walls connecting the tip and the opening, and then injection molding resin A into the grooves of the member.

3. The method for manufacturing a composite molded article according to claim 2, wherein the groove is formed by laser irradiation.

4. A grooved member having a joint, at which it is integrated with a molded product made of resin A to form a composite molded product, the member having a spherical void with a diameter in the range of 1.0 to 200 μm inside, the total volume of the void being 15 to 30% of the total volume, and having a plurality of grooves connected to the void, the grooves having a slit-shaped opening, which gradually narrows in width and extends partway to the depth, and which have a sharp tip and a pair of opposing groove walls connecting the tip and the opening.

5. The composite molded article according to claim 1, wherein the member is made of thermoplastic resin B.

6. The composite molded article according to claim 5, wherein the difference between the decomposition temperature and melting point of the thermoplastic resin B is 250°C or less.

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