Composite and production method for composite

Abstract

The present invention discloses a new technique for improving damping performance of a composite having a first plate-shaped member, a second plate-shaped member, and a resin cured product sandwiched between the first plate-shaped member and the second plate-shaped member. This composite has a first plate-shaped member, a second plate-shaped member, and a resin cured product, and is characterized in that the resin cured product is sandwiched between the first plate-shaped member and the second plate-shaped member, the resin cured product contains air bubbles, and the loss coefficient η1 of the composite is 0.02-0.25.

Description

Composite and method for producing the composite

[0001] The present application discloses composites and methods for making the composites.

[0002] Composites with vibration-damping properties (vibration-damping properties) are used in various technical fields. For example, by employing composites with vibration-damping properties as automobile parts, it is possible to reduce noise and vibrations while the automobile is running, as well as unpleasant vibrations and impact sounds when the automobile passes over uneven surfaces. A composite with vibration-damping properties includes, for example, a first plate-shaped member, a second plate-shaped member, and a cured resin sandwiched between them. The vibration-damping properties of a composite having such a configuration are largely dependent on the properties of the cured resin (see Patent Documents 1 to 6).

[0003] International Publication No. 2019 / 087877 Japanese Patent Laid-Open No. 3-000759 Japanese Patent Laid-Open No. 55-016073 Japanese Patent Laid-Open No. 2012-210722 Japanese Patent Laid-Open No. 2-070777 Japanese Patent Laid-Open No. 2023-542105

[0004] A new technology is needed to improve the vibration-damping performance of a composite having a first plate-shaped member, a second plate-shaped member, and a cured resin sandwiched between them.

[0005] The present application discloses the following multiple aspects as means for solving the above problems: <Aspect 1> A composite comprising a first plate-shaped member, a second plate-shaped member, and a cured resin, the cured resin being sandwiched between the first plate-shaped member and the second plate-shaped member, the cured resin containing bubbles, and a loss factor η of the composite. １ is 0.02 or more and 0.25 or less, and wherein the loss factor η １is the loss factor measured by dynamic viscoelasticity measurement in a three-point bending mode at a measurement frequency of 10 Hz, and is the largest loss factor among those measured at temperatures between 0°C and 30°C. <Aspect 2> The composite of Aspect 1, wherein the thickness of the cured resin in the plate thickness direction is 0.50 mm or less. <Aspect 3> The composite of Aspect 1 or 2, wherein the cured resin contains components derived from resin (A) and curing agent (B) and components obtained after foaming of blowing agent (C). <Aspect 4> The composite of Aspect 3, wherein the cured resin is obtained by foaming 0.1 parts by mass or more and 20 parts by mass or less of the blowing agent (C) with respect to 100 parts by mass of the resin (A). <Aspect 5> The composite of any of Aspects 1 to 4, wherein the bubble size is 10 μm or more and 3000 μm or less.

[0006] The composite of the present disclosure has excellent vibration damping performance (vibration attenuation performance).

[0007] 1 is a schematic diagram showing an example of a cross-sectional structure of a composite; 2 is a schematic diagram showing an example of a flow of a manufacturing method of a composite; 3 is a graph showing the loss factor η １ , the horizontal axis is the loss factor η ２ The graph shows the case where the loss factor η is plotted on the vertical axis for the examples and comparative examples. １ , the horizontal axis is the loss factor η ２ 10 shows a graph in which the following is plotted:

[0008] 1. Composite As shown in Fig. 1, a composite 100 according to one embodiment includes a first plate-shaped member 10, a second plate-shaped member 20, and a cured resin material 30. The cured resin material 30 is sandwiched between the first plate-shaped member 10 and the second plate-shaped member 20. The cured resin material 30 contains bubbles 31. The loss factor η of the composite 100 is １ is 0.02 or more and 0.25 or less. １ is the loss factor measured by dynamic viscoelasticity measurement in a three-point bending mode at a measurement frequency of 10 Hz, and is the largest loss factor between 0°C and 30°C.

[0009] 1.1 Plate-like Member The composite 100 has a first plate-like member 10 and a second plate-like member 20. Here, the "plate-like member" does not need to be entirely plate-shaped, and may be partially shaped or processed to have curves, irregularities, or the like, depending on the intended use. The planar shapes and thicknesses of the first plate-like member 10 and the second plate-like member 20 are not particularly limited and can be selected appropriately depending on the intended use.

[0010] The material of each of the first plate-shaped member 10 and the second plate-shaped member 20 is not particularly limited and may be at least one selected from, for example, a metal material, a plastic material, a rubber material, a fiber-reinforced plastic (FRP), etc. The first plate-shaped member 10 and the second plate-shaped member 20 may be made of the same material or different materials. In particular, excellent strength is likely to be ensured when one or both of the first plate-shaped member 10 and the second plate-shaped member 20 are made of a metal material. Furthermore, excellent strength is likely to be ensured when one or both of the first plate-shaped member 10 and the second plate-shaped member 20 are made of a fiber-reinforced plastic material.

[0011] The type of metal material is not particularly limited and may be, for example, at least one selected from iron, titanium, aluminum, magnesium, and alloys thereof, etc. Examples of alloys include iron-based alloys (including stainless steel), Ti-based alloys, Al-based alloys, and Mg alloys.

[0012] In one embodiment, one or both of the first plate-shaped member 10 and the second plate-shaped member 20 may be made of steel. When one or both of the first plate-shaped member 10 and the second plate-shaped member 20 are made of steel, excellent strength and workability are easily ensured. The steel material is not particularly limited, but may be one standardized by the Japanese Industrial Standards (JIS) or the like. Specific examples include carbon steel, alloy steel, and high-tensile steel used for general structures and mechanical structures. The components of the steel material are not particularly limited, but may contain one or more of Mn, Si, P, Al, N, Cr, Mo, Ni, Cu, Ca, Mg, Ce, Hf, La, Zr, and Sb in addition to Fe and C. For example, the steel material may contain C, Si, Mn, P, S, Al, and N, with the balance being Fe and impurities. As described above, the first plate-shaped member 10 and the second plate-shaped member 20 may be made of the same material or different materials, but it is preferable that they be made of the same material from the viewpoint of workability, etc. For example, both the first plate-shaped member 10 and the second plate-shaped member 20 may be made of steel.

[0013] The plate-shaped member made of steel may be optionally surface-treated. Here, the surface treatment may be at least one selected from, for example, various plating treatments such as zinc plating (hot-dip galvanizing, electrogalvanizing, etc.) and aluminum plating, chemical conversion treatments such as chromate treatment and non-chromate treatment, and physical surface roughening treatments such as sandblasting or chemical surface roughening treatments such as chemical etching, but is not limited to these. Furthermore, the plate-shaped member may be subjected to alloy plating or multiple types of surface treatments. It is preferable that the surface treatment of the plate-shaped member made of steel be at least a treatment aimed at imparting rust resistance.

[0014] The thickness of the plate-shaped member made of a metal material is not particularly limited, but may be, for example, 0.1 mm or more and 3.5 mm or less from the viewpoints of strength, processability, etc. The thickness may be 0.4 mm or more or 0.8 mm or more, and may be 1.6 mm or less or 1.4 mm or less. These lower and upper limits may be any combination. The first plate-shaped member 10 and the second plate-shaped member 20 may each have a uniform thickness or may have thicknesses that vary from portion to portion. Furthermore, the first plate-shaped member 10 and the second plate-shaped member 20 may have the same thickness or may have different thicknesses. The thickness can be determined by observing a cross section of the composite 100.

[0015] Fiber-reinforced plastic (FRP) is a material in which a matrix resin is reinforced with a fiber material. The types of resin and fiber material are not particularly limited. FRP may consist only of a matrix resin and a fiber material. Alternatively, FRP may contain various additives, such as conductive particles, inorganic fillers, rubber materials, pigments, colorants, antioxidants, and flame retardants, for purposes such as imparting functionality. FRP may be single-layered or multi-layered, and the number of layers may be selected depending on the application. The thickness of the FRP is preferably 0.2 mm or more and 3.0 mm or less. The thickness may be 0.5 mm or more or 1.0 mm or more, or 2.5 mm or less or 2.0 mm or less. These lower and upper limits may be any combination. The thickness can be determined by observing a cross section of the composite 100.

[0016] The matrix resin contained in the fiber reinforced plastic material (FRP) is not particularly limited and may be a thermoplastic resin, a thermosetting resin, or a combination thereof. Thermoplastic resins in particular have good bending strength and excellent processability. For example, the thermoplastic resin may be contained in an amount of 50 parts by mass or more, 60 parts by mass or more, 70 parts by mass or more, 80 parts by mass or more, or 90 parts by mass or more per 100 parts by mass of the resin component. The matrix resin may be a thermoplastic resin only. The thermoplastic resin that can be used for the matrix resin is not particularly limited, and may be one or more selected from, for example, polyolefins and acid-modified products thereof, polypropylene, polystyrene, polymethyl methacrylate, AS resin, ABS resin, thermoplastic aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, thermoplastic epoxy resin, polyimide, polyamide, polyamideimide, polyetherimide, polyethersulfone, polyphenylene ether and modified products thereof, polyphenylene sulfide, polyoxymethylene, polyarylate, polyether ketone, polyether ether ketone, polyether ketone ketone, and nylon. The thermosetting resin that can be used for the matrix resin is not particularly limited, and may be one or more selected from, for example, epoxy resins, vinyl ester resins, phenolic resins, and urethane resins.

[0017] The fiber material contained in the fiber reinforced plastic material (FRP) is not particularly limited and may be, for example, at least one type selected from carbon fiber, boron fiber, silicon carbide fiber, glass fiber, aramid fiber, etc. The fiber material may be long fiber or short fiber. FRP containing carbon fiber in particular has excellent strength. The type of carbon fiber may be, for example, either PAN-based or pitch-based, and can be selected depending on the purpose and application. The fiber material may be only one type of the above-mentioned fibers or a combination of multiple types.

[0018] Examples of the reinforcing fiber substrate (prepreg) that serves as the substrate for the above-mentioned fiber material include a nonwoven fabric substrate using chopped fiber, a cross material using continuous fiber, a unidirectional reinforcing fiber substrate (UD material), etc. From the viewpoint of reinforcing effect, it is preferable to use a cross material or a UD material as the reinforcing fiber substrate.

[0019] The volume fraction Vf of the fiber material in the FRP is not particularly limited, but from the viewpoint of strength and processability, it is preferably 20% by volume or more and 70% by volume or less. The Vf of the fiber material in the FRP is more preferably 25% by volume or more or 30% by volume or more, and more preferably 65% ​​by volume or less or 60% by volume or less. These lower and upper limits may be arbitrarily combined. Measurement of Vf can be performed by a method known to those skilled in the art.

[0020] 1.2 Cured Resin The composite 100 has a cured resin 30 between the first plate-like member 10 and the second plate-like member 20. The cured resin 30 contains bubbles 31. The cured resin 30 containing bubbles 31 exhibits excellent vibration-damping performance.

[0021] The cured resin material 30 may be any material as long as it has a definite shape and is capable of retaining the bubbles 31. The cured resin material 30 may contain, for example, components derived from the resin (A) and the curing agent (B) and components resulting from the foaming of the foaming agent (C). By analyzing the components contained in the cured resin material 30, the types and amounts of the "components derived from the resin (A) and the curing agent (B)" and the "components resulting from the foaming of the foaming agent (C)" can be identified. The types and amounts of the resin (A) and the curing agent (B) can be identified from the types and amounts of the "components derived from the resin (A) and the curing agent (B)." The type and amount of the foaming agent (C) can be identified from the types and amounts of the "components resulting from the foaming of the foaming agent (C)." In this embodiment, the components contained in the cured resin material 30 can be identified using a known method. For example, but not limited to, pyrolysis GC-MS (Gas Chromatography-Mass Spectrometry) measurement can be used to analyze the components contained in a cured resin material by directly and instantaneously thermally decomposing a small amount of cured resin material at a high temperature and introducing the generated gas components into a GC-MS.

[0022] Resin (A) has a loss factor η １ Any resin can be used as long as it can achieve the above. Examples of resin (A) that can be used include vinyl chloride resin, vinyl acetate resin, polyvinyl alcohol, polycarbonate, polyvinyl butyral, polystyrene, ABS resin, polymethyl methacrylate (methacrylic resin), polyphenylene oxide, ionomer resin, cellulose-based plastic, polyethylene, polypropylene, polyamide (nylon), polyacetal (polyoxymethylene), polyphenylene sulfide, vinylidene chloride resin, polyethylene terephthalate, fluororesin, phenolic resin, urea resin, melamine resin, polyester resin, unsaturated polyester resin, diallyl phthalate resin, epoxy resin, silicon resin, alkyd resin, polyimide, polyaminobismaleimide, casein resin, furan resin, urethane resin, polyesterurethane resin, etc. These may be used alone or in combination of two or more.

[0023] The curing agent (B) may be any agent that accelerates the curing of the resin (A). For example, when the resin (A) is an epoxy resin, an amine-based curing agent or an acid anhydride curing agent may be used as the curing agent (B). When the resin (A) is a urethane resin, a polyisocyanate compound or the like may be used as the curing agent (B).

[0024] The foaming agent (C) may be any foaming agent that generates bubbles 31 in the cured resin 30. The foaming agent (C) may be, for example, at least one selected from azodicarbonamide (ADCA), N,N'-dinitrosopentamethylenetetramine (DPT), 4,4'-oxybis(benzenesulfonylhydrazide) (OBSH), hydrazodicarbonamide (HDCA), barium azodicarboxylate, sodium hydrocarbonate, and the like.

[0025] Furthermore, in order to adjust the gas generation temperature by the blowing agent (C), a blowing aid (D) may be used in combination with the blowing agent (C) as necessary. Examples of the blowing aid (D) include urea-based aids, vulcanization accelerators, salicylic acid, and zinc oxide. Examples of urea-based aids include CEL PASTE 101, CEL PASTE 101W, CEL PASTE K5, CEL PASTE K4, and CEL PASTE M3 manufactured by Eiwa Chemical Industry Co., Ltd. Examples of vulcanization accelerators include trimethylthiourea, 2-mercaptobenzothiazole, tetramethylthiuram disulfide, zinc dimethyldithiocarbamate, and zinc diethyldithiocarbamate. The blowing aid (D) may be used alone or in combination of two or more.

[0026] According to the findings of the present inventors, if the amount of the blowing agent (C) is too small, the loss factor η １ If the amount of foaming agent (C) is too large, the foaming rate becomes too high, the amount of resin decreases accordingly, and the loss factor η １ Furthermore, if the amount of foaming agent (C) is too large, the resin (A) tends to escape from the gap between the first plate-like member 10 and the second plate-like member 20 as the resin (A) is cured, and as a result, air bubbles are not introduced well, and the loss factor η １ According to the findings of the present inventors, when the cured resin 30 is obtained by foaming 100 parts by mass of the resin (A) with 0.1 parts by mass or more and 20 parts by mass or less of the foaming agent (C), the loss factor η １ In particular, when the cured resin 30 is obtained by foaming 0.5 parts by mass or more and 5 parts by mass or less of the foaming agent (C) relative to 100 parts by mass of the resin (A), even more excellent vibration-damping performance is easily ensured.

[0027] The resin composition before curing of the cured resin 30 may contain a curing accelerator (E) as an optional component. The curing accelerator (E) may be appropriately selected depending on the type of resin (A), etc. The amount of the curing accelerator (E) to be added depends on the type of the curing accelerator (E).

[0028] The resin composition before curing of the cured resin 30 may contain various additives (F) such as a component that contributes to improving vibration damping properties, an impact resistance modifier, an adhesion imparting agent, an antifoaming agent, and a leveling agent as optional components. When the cured resin 30 contains, for example, a component that contributes to improving vibration damping properties, an impact resistance modifier, or an adhesion imparting agent as the various additives (F), the loss factor η of the composite 100 １ Further improvement of the properties can be expected, and improvement of the fracture toughness of the cured resin 30 constituting the composite 100 and improvement of the adhesion to the plate-like member can also be expected. Examples of components that contribute to improving vibration damping include rosin-based resins. Examples of impact resistance modifiers and adhesion promoters include core-shell rubber particles, carboxyl-terminated butadiene nitrile rubber (CTBN), thermoplastic elastomers, and acrylic block copolymers. The various additives (F) may be used singly or in combination of two or more.

[0029] As described above, the cured resin 30 is sandwiched between the first plate-shaped member 10 and the second plate-shaped member 20. That is, the cured resin 30 can have a predetermined thickness in the plate thickness direction of the first plate-shaped member 10 and the second plate-shaped member 20. The thickness of the cured resin 30 in the plate thickness direction is not particularly limited as long as bubbles 31 are present. According to the findings of the present inventors, sufficient vibration damping performance can be exhibited even when the thickness of the cured resin 30 in the plate thickness direction is thin. For example, excellent vibration damping performance can be exhibited even when the thickness of the cured resin 30 in the plate thickness direction is 0.50 mm or less. The thickness may be 0.10 mm or more and 0.50 mm or less. The thickness may be 0.15 mm or more, 0.20 mm or more, or 0.25 mm or more, or 0.45 mm or less, 0.40 mm or less, or 0.35 mm or less. These lower and upper limits may be any combination.

[0030] As described above, the cured resin 30 contains the bubbles 31. As will be described later, by introducing the bubbles 31 into the cured resin 30, the loss factor η １According to the findings of the present inventors, when the size of the bubbles 31 contained in the cured resin 30 is 10 μm or more and 3000 μm or less, the loss factor η １ It is easy to further improve the loss factor η １ From the viewpoint of further improving the above, the size of the bubbles 31 may be 50 μm or more, 100 μm or more, 200 μm or more, or 300 μm or more, and may be 2500 μm or less, 2000 μm or less, or 1500 μm or less. These lower limit values ​​and upper limit values ​​may be any combination.

[0031] In this application, "bubble size" refers to the "average circle-equivalent diameter of bubbles" measured by X-ray CT. Specifically, a three-dimensional image of the cured resin is obtained by X-ray CT. From the obtained three-dimensional image, information on a cross section that cuts through the half-thickness position of the cured resin in the surface direction is obtained. Each of the multiple bubbles contained in the cross section is converted into a circle of the same area to determine the equivalent diameter. The number average value of each circle-equivalent diameter is considered to be the "bubble size." The measurement conditions for X-ray CT are as follows: X-ray CT measurement device: Xradia520Versa (manufactured by ZEISS) Tube voltage: 30 kV Tube current: 0.67 mA Magnification axial ratio: 0.4x (lens magnification) Analysis method: Analysis was performed using image analysis software "Avizo Inspect" manufactured by Thermo Fisher Scientific.

[0032] The bubble identification method is explained in more detail below. Bubbles are identified by using two functions—Watershed (Separate Object) and Opening—of the image analysis software "Avizo Inspect" in 3D images obtained by X-ray CT. Watershed is a method for identifying two connected bubbles as two separate bubbles rather than a single bubble. Specifically, a point a certain distance from the bubble's outline is defined as the bubble's core. The area of ​​the core expanded until it touches the bubble's outline or another core is considered a bubble. Opening is a method for identifying individual bubbles when multiple connected bubbles form a dumbbell shape. Specifically, compressing a bubble causes the axis of the dumbbell shape to disappear, allowing the two separated bubbles to be identified. Then, by returning the bubble size by the amount of compression, the disappeared area can be identified as a single bubble based on the difference between the pre- and post-compression images.

[0033] 1.3 Loss Factor According to the new findings of the present inventors, the loss factor η of the composite 100 １ Only when the loss factor η of the composite 100 is within a certain range, the loss factor η of the composite 100 can be increased by including the air bubbles 31 in the cured resin 30. １ The loss factor η of the composite 100 is improved. １ In the region where exceeds a certain value, the loss factor η of the composite 100 is smaller when the cured resin 30 does not contain bubbles than when the cured resin 30 contains bubbles 31. １ That is, the loss factor η of the composite 100 is likely to increase. １ In the region where the loss factor η of the composite 100 exceeds a certain value, the advantageous effect of introducing the air bubbles 31 into the cured resin 30 is lost, and in fact, the composite 100 has better performance without introducing the air bubbles 31. １ If the loss factor η is below a certain value, it is difficult to improve the loss factor even if the bubbles 31 are introduced. １ The improvement effect of the loss factor η of the composite 100 １ This becomes significant when the loss factor η of the composite 100 is 0.02 or more and 0.25 or less. １When the loss factor η of the composite 100 is 0.10 or more and 0.25 or less, the introduction of bubbles exerts a more excellent effect. １ may be 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, 0.09 or more, 0.10 or more, 0.11 or more, or 0.12 or more, and may be 0.24 or less, 0.23 or less, 0.22 or less, 0.21 or less, or 0.20 or less.

[0034] Furthermore, even when the cured resin itself (cured resin without bubbles 31) constituting the cured resin 30 has a loss factor equal to or greater than a certain value and equal to or less than a certain value, the loss factor η of the composite 100 due to the introduction of bubbles 31 can be reduced. １ The effect of increasing the loss factor is enhanced. For example, by blending the above-mentioned additives with the resin, the amount of components not incorporated into the crosslinked structure of the resin increases, reducing the crosslink density of the cured product and the elastic modulus. A decrease in the elastic modulus of the resin increases the density of strain energy concentrated at the interface between the voids caused by the bubbles and the resin, thereby improving the loss factor and further enhancing the vibration-damping effect. However, if the amount of additive is increased to further increase the loss factor of the cured resin 30, the elastic modulus further decreases, making it difficult to maintain the shape, making it impossible to introduce bubbles into the cured resin 30, and no longer contributing to an increase in the loss factor. According to the findings of the inventors, when the loss factor of the cured resin itself (the cured resin without the bubbles 31) constituting the cured resin 30 is 0.02 or more and 0.25 or less, the effect of introducing bubbles to increase the loss factor is significant. When the loss factor of the cured resin itself is less than 0.02, the elastic modulus is high and the density of strain energy concentrated at the interface between the voids caused by the bubbles and the resin is small, making it difficult to achieve an increase in the loss factor by introducing bubbles. Furthermore, if the loss factor of the cured resin itself exceeds 0.25, the elastic modulus is so low that it becomes difficult to maintain the shape, and it becomes impossible to introduce air bubbles into the cured resin, resulting in a loss factor η １ does not improve.

[0035] In this application, the loss factor η １" is the loss factor measured by dynamic mechanical analysis (DMA) in a three-point bending mode at a measurement frequency of 10 Hz, and is the largest loss factor between 0°C and 30°C. DMA is a method for measuring the mechanical properties of a sample by applying time-varying strain or stress (vibration) to the sample and measuring the resulting stress or strain. DMA can be used to measure the temperature and frequency dependencies of the storage modulus, loss modulus, loss factor, etc. as the viscoelastic properties of the sample, and among these, the loss factor is generally used as an index of vibration damping performance. Loss factor η of a composite １ The loss factor can be measured by cutting out a portion of the composite and placing the resulting sample in a predetermined position in a device for measuring the loss factor. The size of the sample is not particularly limited, as long as the loss factor can be measured. For example, a sample 10 mm wide and 20 to 55 mm long is cut out from the composite using a cutter, and the loss factor is measured. A desirable size is 10 mm wide and 40 mm long. A DMA7100 manufactured by Hitachi High-Tech Science Corporation is used to measure the loss factor. The measurement conditions are a two-cycle heating cycle: heating from -100°C to 200°C at 2°C / min, cooling from 200°C to -100°C, and then heating again from -100°C to 200°C at 2°C / min. The measurement frequency is set to 10 Hz, and the loss factor is measured during the second heating cycle in three-point bending mode. The same applies when measuring the "loss factor of the cured resin itself." In this case, a bubble-free cured resin can be separately prepared and the loss factor measured in the same manner. For example, a cured resin product for measuring the loss factor can be prepared by forming a bubble-free cured resin product between the first and second plate-shaped members and then peeling the first and second plate-shaped members apart. Alternatively, the loss factor of the composite may be substantially the same as that of the cured resin product 30, regardless of whether or not the first and second plate-shaped members are present (the plates themselves have little effect on the loss factor). In this case, the loss factor of the composite itself may be measured without peeling the first and second plate-shaped members, and this may be considered as the loss factor of the cured resin itself.

[0036] 1.4 Elastic Modulus of Resin Constituting the Cured Resin Product In the composite 100 according to one embodiment, when the elastic modulus of the resin constituting the cured resin product 30 (the portion of the cured resin product 30 excluding the bubbles 31) is within a predetermined range, the loss factor η １ For example, the elastic modulus of the resin at 0 to 30°C may be 1200 MPa or more and 3000 MPa or less. The elastic modulus may be 1500 MPa or more, 1750 MPa or more, or 2000 MPa or more, and may be 2750 MPa or less, 2500 MPa or less, or 2250 MPa or less. In particular, when the elastic modulus is 1750 MPa or more and 2250 MPa or less and the size of the cells 31 is within the above-mentioned predetermined range, the loss factor η １ In the present application, the "elastic modulus" of a resin is measured by a tensile test.

[0037] 1.5 Effects As described above, the composite 100 according to one embodiment has the cured resin 30 containing the bubbles 31 between the first plate-like member 10 and the second plate-like member 20. Here, since the cured resin 30 contains the bubbles 31, it is thought that when the composite 100 vibrates, strain energy is concentrated at the interface between the voids caused by the bubbles 31 and the resin, thereby enhancing the vibration damping effect, and the loss factor η １ According to the findings of the present inventors, the effect of introducing air bubbles is to improve the loss factor η of the composite 100. １ is in the range of 0.02 or more and 0.25 or less. １ In the region where the loss factor is in the range of 0.02 or more and 0.25 or less, when the composite 100 includes the cured resin material 30 containing bubbles, the loss factor is significantly improved and the vibration damping capacity is dramatically improved compared to when the composite includes a cured resin material that does not contain bubbles. In addition, by including bubbles in the cured resin material 30, a reduction in the amount of resin and a reduction in the weight of the composite 100 can be expected.

[0038] 1.6 Uses The composite 100 is used in various parts that require vibration-damping performance (vibration-damping performance). For example, the composite 100 may be used as a part for transportation equipment such as automobiles, railway vehicles, ships, and aircraft. Alternatively, the composite 100 may be used as a part for construction components or other parts other than transportation equipment.

[0039] 2. Manufacturing Method of Composite As shown in Figure 2, a manufacturing method of a composite 100 according to one embodiment includes: Step 1: mixing a main agent containing a resin (A) and a foaming agent (C) with a curing agent (B) at a temperature of 40°C or higher and 90°C or lower to obtain a resin composition; Step 2: stacking a first plate-like member and a second plate-like member so as to sandwich the resin composition therebetween to obtain a laminate; and Step 3: foaming the foaming agent (C) contained in the resin composition in the laminate and curing the resin composition. Here, the loss factor η of the composite is １ is equal to or greater than 0.02 and equal to or less than 0.25.

[0040] 2.1 Step 1 In step 1, a base agent containing a resin (A) and a foaming agent (C) is mixed with a curing agent (B) at a temperature of 40° C. or higher and 90° C. or lower to obtain a resin composition.

[0041] The compounding ratio of the resin (A) to the foaming agent (C) in the base resin is not particularly limited. However, as described above, when a predetermined amount of the foaming agent (C) is used relative to the resin (A), better vibration damping performance is likely to be ensured. Specifically, the resin composition obtained in step 1 preferably contains 0.1 parts by mass to 20 parts by mass, or 0.5 parts by mass to 5 parts by mass, of the foaming agent (C) relative to 100 parts by mass of the resin (A).

[0042] The mixing ratio of the base agent and the curing agent (B) is not particularly limited, and an appropriate amount of the curing agent (B) may be used depending on the amount of the resin (A). The mixing temperature of the base agent and the curing agent (B) is 40°C or higher and 90°C or lower, preferably 50°C or higher and 80°C or lower, and more preferably 60°C or higher and 70°C or lower. If the mixing temperature is too low, it may be difficult to uniformly disperse each component. If the mixing temperature is too high, the curing reaction may proceed. The mixing time of the base agent and the curing agent (B) is not particularly limited, and may be any time that allows each component to be uniformly mixed. Various mixing devices may be used as a means for mixing the base agent and the curing agent (B).

[0043] 2.2 Step 2 In step 2, a first plate-shaped member and a second plate-shaped member are stacked together so as to sandwich the resin composition obtained in step 1, thereby obtaining a laminate. For example, the resin composition is applied to one or both of the first plate-shaped member and the second plate-shaped member, and then the first plate-shaped member and the second plate-shaped member are stacked together so as to sandwich the applied resin composition. Various coating devices may be used as the coating means. The thickness of the cured resin product after curing can be adjusted by adjusting the amount of resin composition applied. As described above, the thickness of the cured resin product in the plate thickness direction after curing the resin composition may be 0.50 mm or less. The thickness may be 0.10 mm or more and 0.50 mm or less, or 0.20 mm or more and 0.40 mm or less.

[0044] 2.3 Step 3 In step 3, in the laminate obtained in step 2, the foaming agent (C) contained in the resin composition is foamed and the resin composition is cured. For example, the resin composition is heated to a predetermined temperature to foam the foaming agent (C) and cure the resin composition. The foaming and curing temperatures depend on the types of resin (A), curing agent (B), and foaming agent (C). In step 3, the laminate may be press-held. More specifically, the laminate may be heated while being pressed and held using a hot press.

[0045] 2.4 Supplementary Information A composite can be manufactured through the above steps 1 to 3. Here, as mentioned above, the loss factor η １When the loss factor η is 0.02 or more and 0.25 or less, the loss factor η due to the introduction of bubbles into the cured resin １ In particular, the improvement effect of the loss factor η １ When the loss factor η of the composite 100 is 0.10 or more and 0.25 or less, the introduction of bubbles exerts a more excellent effect. １ may be 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, 0.09 or more, 0.10 or more, 0.11 or more, or 0.12 or more, and may be 0.24 or less, 0.23 or less, 0.22 or less, 0.21 or less, or 0.20 or less.

[0046] According to the findings of the present inventors, the loss factor η of the composite can be reduced by the above-mentioned manufacturing method. １ and the loss factor η of the following comparative composites ２ Relative to η １ / η ２ The ratio η can be 1.1 or more. Here, the comparative composite has the same structure as the composite except that it does not contain bubbles. １ / η ２ may be 1.1 or more and 2.0 or less, 1.2 or more and 2.0 or less, or 1.3 or more and 2.0 or less.

[0047] 3. Supplementary Information Regarding Prior Art Note that the methods for measuring the loss factor differ between the inventions disclosed in Patent Documents 3 to 6 and the composite of the present disclosure. Patent Document 5 discloses a technique for introducing air bubbles into a resin by blowing air into it. The loss factors of the inventions disclosed in Patent Documents 3 to 6 are considered to be outside the range of 0.02 or more and 0.25 or less when measured using the measurement method of the present disclosure.

[0048] As described above, a composite and a method for producing the same according to one embodiment have been described, but the technology of the present disclosure is not limited to the above embodiment and various modifications are possible. Below, the effects of the technology of the present disclosure will be described in more detail using examples, but the technology of the present disclosure is not limited to the following examples.

[0049] 1. Preparation of Resin Composition In this example, an epoxy resin (YD-127 manufactured by Nippon Steel Chemical & Material Co., Ltd.) or a copolymer polyester composition (Pylon (registered trademark) UR manufactured by Toyobo MC Co., Ltd.) is used as the resin (A), but the type of resin (A) applicable to the composite of the present disclosure is not limited to these.

[0050] 1.1 Introducing Bubbles into Cured Resin Among the resin compositions shown in Tables 1 to 4 below, those using DICY as the curing agent (B) were prepared as follows. First, a portion of the resin (A) was set aside, and the foaming agent (C), foaming aid (D), curing agent (B) (trade name: DICY15), and curing accelerator (E) (trade name: DCMU) were uniformly dispersed using a three-roll mill to prepare composition X. All components shown in Tables 1 to 4 below, except for those used to prepare composition X, were weighed into a glass flask and heated and mixed at 150°C to obtain a uniform masterbatch. Next, the obtained masterbatch was cooled to below 60°C, and then composition X was weighed and added. The mixture was heated and mixed at 60 to 70°C to obtain a uniform dispersion, yielding a resin composition. The compositions of the obtained resin compositions are as shown in Tables 1 to 4 below.

[0051] Of the resin compositions shown in Tables 1 to 4 below, those using TPP as the curing agent (B) were prepared as follows: All components shown in Tables 1 to 4 below were weighed into a glass flask and mixed under heating at 60 to 70°C to obtain a resin composition.

[0052] 1.2 Cases in which bubbles are not introduced into the cured resin Among the resin compositions shown in Tables 1 to 4 below, those using DICY as the curing agent (B) were prepared as follows. First, a portion of the resin (A) was set aside, and curing agent (B) (trade name: DICY15) and curing accelerator (E) (trade name: DCMU) were uniformly dispersed using a three-roll mill to prepare composition Y. All of the components shown in Tables 1 to 4 below, except for those used to prepare composition Y, were weighed into a glass flask and heated and mixed at 150°C to obtain a uniform masterbatch. Next, the obtained masterbatch was cooled to below 60°C, and then composition Y was weighed and added. The mixture was heated and mixed at 60 to 70°C to obtain a uniform dispersion, yielding a resin composition. The compositions of the obtained resin compositions are as shown in Tables 1 to 4 below.

[0053] Of the resin compositions shown in Tables 1 to 4 below, those using TPP as the curing agent (B) were prepared as follows: All components shown in Tables 1 to 4 below were weighed into a glass flask and mixed under heating at 60 to 70°C to obtain a resin composition.

[0054] 2. Preparation of Composite Two steel plates (thickness: 0.4 mm) were prepared. The resin composition obtained as described above was applied to one of the steel plates using an applicator to a uniform thickness. The other steel plate was placed on the applied surface together with a PTFE spacer to obtain a laminate consisting of steel plate / resin composition / steel plate. The laminate was pressed and held at a predetermined temperature in a hot press to obtain a composite (sandwich steel plate) consisting of steel plate / cured resin / steel plate. The thickness of the cured resin in the plate thickness direction was 400 μm. The obtained composite was cut into a length of 40 mm and a width of 10 mm to prepare a test piece for measuring the loss factor.

[0055] 3. Measurement of loss factor The loss factor of the obtained composite was measured. The method for measuring the loss factor is as described in the embodiment.

[0056] 4. Confirmation of the Presence or Absence of Air Bubbles The above test piece was cut and the cut surface was visually inspected to confirm the presence or absence of air bubbles.

[0057] 5. Evaluation Results Tables 1 to 4 below show the composition, curing temperature, curing time, presence or absence of bubbles, and loss coefficient η when bubbles are present for each resin composition of the examples and comparative examples. １ , and the loss coefficient η when no air bubbles are included ２ The "Kane Ace MX-154" in Tables 1 to 4 is a masterbatch in which 40% core-shell rubber is dispersed in 60% epoxy resin. In Table 4, the values ​​in parentheses shown for the examples and comparative examples using "Kane Ace MX-154" are overall values ​​obtained by dividing Kane Ace MX-154 into epoxy resin and core-shell rubber, and assuming resin (A) to be 100 parts by mass.

[0058] In addition, in Figures 3 and 4, the vertical axis shows the loss factor η １ , the horizontal axis is the loss factor η ２ 3 is a graph showing the results of the example in which the amount of the blowing agent (C) in the resin composition is 5.0 parts by mass. FIG. 4 is a graph showing the results of all the examples and comparative examples, and among these, the results of the example in which the amount of the blowing agent (C) in the resin composition is 5.0 parts by mass and the results of the example in which the amount of the blowing agent (C) in the resin composition is 20.0 parts by mass are shown as line graphs.

[0059]

[0060]

[0061]

[0062]

[0063] From the results shown in Tables 1 to 4 and Figures 3 and 4, the loss factor η of the composite when air bubbles are contained in the cured resin １ The loss factor η of the composite without bubbles is ２ It can be seen that in some cases the loss factor η of the composite is significantly improved. It is thought that the inclusion of bubbles in the cured resin concentrates strain energy at the interface between the voids created by the bubbles and the resin when the composite vibrates, thereby enhancing the vibration damping effect. As is clear from Figure 4, the effect of introducing bubbles is such that the loss factor η of the composite is significantly improved. １This phenomenon occurs specifically when the loss factor η of the composite is in the range of 0.02 or more and 0.25 or less. １ In the region where exceeds 0.25, the loss factor η when air bubbles are contained in the cured resin １ Loss factor η without bubbles ２ In other words, the effect of introducing air bubbles is lost. As is clear from the results shown in Tables 1 to 4 and Figures 3 and 4, the loss factor η １ In the region where is less than 0.02, the loss factor η can be reduced by including air bubbles in the cured resin. １ Although it can improve the performance, the effect is small.

[0064] Loss factor η １ In the region where the loss coefficient η exceeds 0.25, the introduction of air bubbles １ The reason why the resin does not contribute to the improvement of the properties is thought to be, for example, as follows: if the loss factor is high and the modulus of elasticity is low (soft), air bubbles escape together with the resin during foaming and curing, and the air bubbles are not introduced into the resin in an appropriate manner, and furthermore, the amount of resin is thought to be reduced.

[0065] Loss factor η １ In the region where is less than 0.02, the loss coefficient η due to the introduction of bubbles １ The reason for the decrease in the improvement effect of (1) is thought to be, for example, as follows: Even if air bubbles are introduced into a resin with a small loss factor and a high elastic modulus (hard), when the composite vibrates, it is difficult for strain energy to concentrate at the interface between the voids caused by the air bubbles and the resin, and it is possible that almost no vibration-damping effect is obtained.

[0066] Furthermore, as is clear from the results shown in Tables 1 to 4 and FIG. 4, when the amount of foaming agent added to 100 parts by mass of resin is up to 5 parts by mass, the loss factor η １ This is thought to be because an increase in the amount of foaming agent added increases the foam content in the cured resin, allowing for the introduction of a suitable number of bubbles. On the other hand, when the amount of foaming agent added is 10 parts by mass or 20 parts by mass, the loss modulus η １The loss factor tends to become smaller. When the foaming agent is excessive, the foaming rate becomes excessive, and the amount of resin decreases accordingly, which is thought to be the reason for the decrease in the loss factor. Also, when the foaming agent is excessive, in some cases, air bubbles may escape from between the plates during resin hardening, and the air bubbles may not be properly introduced.

[0067] 6. Investigation of Bubble Size The size (average circle equivalent diameter) of bubbles contained in the cured resin was measured for Examples 3, 7, and 11. The method for measuring bubble size was as described in the embodiment of this specification. The results are shown in Table 5 below.

[0068]

[0069] As is clear from the results shown in Table 5, when the size of the bubbles contained in the cured resin is 10 μm or more and 3000 μm or less, the loss factor η １ It can be said that the improvement effect is more significantly enhanced.

[0070] 7. Supplementary Information In the above examples, a steel plate having a thickness of 0.4 mm was used as the plate-like member, but the thickness and material of the plate-like member are not limited to this. The vibration damping performance of the composite is largely dependent on the cured resin that is the intermediate layer, and the thickness and material of the plate-like member have almost no effect on the vibration damping performance of the composite. In other words, regardless of the thickness and material of the plate-like member, the composite has excellent vibration damping performance due to the cured resin. Furthermore, in the above examples, a case in which the thickness of the cured resin in the plate thickness direction is 400 μm was exemplified, but the thickness of the cured resin is not limited to this. Whether the thickness of the cured resin is less than 400 μm or more than 400 μm, as long as it is possible to include air bubbles, the loss factor η １ In the above examples, various compositions of the cured resin were exemplified in order to change the loss factor of the cured resin and the composite, but the composition of the cured resin is not limited to the above examples. The above effect can be achieved by changing the loss factor η １ It is believed that the same effect can be obtained regardless of the composition of the cured resin product as long as the ratio is within the range of 0.02 to 0.25.

[0071] 8. Summary In a composite consisting of plate / adhesive resin (intermediate layer) / plate, vibration damping is achieved by shear deformation of the adhesive resin, which has high vibration damping properties. It is thought that including voids in the adhesive induces shear deformation and enhances the vibration damping effect. This has also been confirmed by simulation. That is, as a result of performing simulation, it was found that in an adhesive layer into which air bubbles have been introduced, high-density strain energy is concentrated at the interface between the voids caused by the air bubbles and the adhesive, thereby further enhancing the vibration damping effect. As in the above example, by including a foaming agent in the resin composition and forming a cured resin containing air bubbles as the intermediate layer in the composite, the loss factor η １ It was confirmed that the vibration damping capacity was improved significantly. However, this improvement was not due to the loss factor η １ It was found that this effect is particularly exhibited when the ratio ρ is 0.02 or more and 0.25 or less. As described above, a composite having the following configurations (1) to (4) can be said to have superior vibration-damping performance (vibration-damping performance) due to the inclusion of bubbles in the cured resin product, compared to a composite that does not contain bubbles. (1) The composite has a first plate-shaped member, a second plate-shaped member, and a cured resin product. (2) The cured resin product is sandwiched between the first plate-shaped member and the second plate-shaped member. (3) The cured resin product contains bubbles. (4) The loss factor η of the composite １ is 0.02 or more and 0.25 or less, and wherein the loss factor η １ is the loss factor measured by dynamic viscoelasticity measurement in a three-point bending mode at a measurement frequency of 10 Hz, and is the largest loss factor between 0°C and 30°C.

[0072] 100 Composite 10 First plate-shaped member 20 Second plate-shaped member 30 Resin cured product 31 Air bubbles

Claims

1. A composite body having a first plate-shaped member, a second plate-shaped member, and a cured resin, the cured resin is sandwiched between the first plate-shaped member and the second plate-shaped member, the cured resin contains bubbles, The loss factor η of the composite １ is 0.02 or more and 0.25 or less, and wherein the loss factor η １ is the loss factor measured by dynamic viscoelasticity measurement in a three-point bending mode at a measurement frequency of 10 Hz, and is the largest loss factor between 0°C and 30°C. Complex.

2. 2. The composite of claim 1 , The thickness of the cured resin in the plate thickness direction is 0.50 mm or less. Complex.

3. 2. The composite of claim 1 , the cured resin contains components derived from the resin (A) and the curing agent (B) and components obtained after foaming of the foaming agent (C), Complex.

4. 4. The composite of claim 3, the cured resin is obtained by foaming 100 parts by mass of the resin (A) with 0.1 parts by mass or more and 20 parts by mass or less of the foaming agent (C), Complex.

5. The composite according to any one of claims 1 to 4, The size of the bubbles is 10 μm or more and 3000 μm or less. Complex.