JP2018187830A - Vibration damping material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration damping material which contains a fiber-reinforced composite material as a constitution material, is lightweight and has vibration damping property and high rigidity, and is suitable for a case of a portable OA equipment.SOLUTION: A vibration damping material 10 has one or more layers of fiber-reinforced composite materials 21 layered on both surfaces of a core material 11, where the core material 11 is formed from a thermosetting resin foam, a resin impregnated in the fiber-reinforced composite material 21 is impregnated and cured on a boundary surface 11b with the fiber-reinforced composited material 21 of the core material 11, and the material has such a cell structure as not to be impregnated with a resin in a thickness central part 11a of the core material 11.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vibration damping material in which layers of a fiber reinforced composite material are laminated on both surfaces of a core material.

  Fiber-reinforced composite materials in which resin is impregnated with carbon fiber and glass fiber are lighter and more rigid than metals such as iron and aluminum, so their use has become widespread with increasing needs for weight reduction of various products. ing. On the other hand, the fiber reinforced composite material is required to improve the vibration damping property because the vibration damping property is impaired due to the light weight.

  Conventionally, in order to improve vibration damping properties, composite materials having a sandwich structure in which viscoelastic material layers are arranged between layers of laminated fiber reinforced composite materials have been proposed (Patent Documents 1 and 2).

JP 2004-291408 A JP 2011-183563 A

  However, the composite material having the viscoelastic material layer does not have sufficient vibration damping performance, and the viscoelastic material layer is impregnated with viscoelastic resin throughout the layer, and has no so-called solid state. Therefore, there is a problem that the weight becomes heavy and the lightness is impaired.

  This invention is made | formed in view of the said point, Comprising: It aims at provision of the damping material which is lightweight and has high rigidity, and is excellent in damping performance.

  The invention according to claim 1 is the vibration damping material in which the fiber reinforced composite material is laminated on both surfaces of the core material, wherein the core material is made of a thermosetting resin foam, and the fiber reinforced composite material of the core material and In the boundary surface, the core material and the fiber reinforced composite material are bonded and fixed by the resin impregnated in the fiber reinforced composite material, and the core material is not impregnated with the resin in the center of the thickness. It has a bubble structure.

A second aspect of the present invention is the first aspect, wherein the thermosetting resin foam is a polyurethane foam having a non-foamed skin layer on a surface, and the density before the lamination (JIS K 7222) is 150 to 500 kg. / M ³ , tensile strength (JIS K 6251) is 0.2 to 5.0 MPa, and elongation (JIS K 6251) is 70 to 200%.

The invention of claim 3 is the invention according to claim 1, wherein the thermosetting resin foam is a polyurethane foam in which a non-foamed skin layer does not exist on the surface, and the density (JIS K 7222) before lamination is 150 to It is characterized by 700 kg / m ³ , tensile strength (JIS K 6251) of 0.5 to 3.2 MPa, and elongation (JIS K 6251) of 160 to 310%.

  The invention of claim 4 is characterized in that, in any one of claims 1 to 3, a ratio of the thickness of the core material to the thickness of the fiber-reinforced composite material in the damping material is 5 to 70%. To do.

The invention of claim 5 is characterized in that, in claim 4, the basis weight before lamination of the thermosetting resin foam constituting the core material is 50 to 500 g / m ² .

  According to the present invention, since the core material sandwiched between the fiber reinforced composite materials has a cell structure that is not impregnated with resin at the thickness center portion, The lightness is improved, and the rigidity of the damping material can be increased by the presence of the fiber reinforced composite material and the resin being bonded and solidified at the interface between the core material and the fiber reinforced composite material.

It is sectional drawing of one Embodiment of the damping material in this invention. It is an expanded sectional view of one embodiment of a damping material. It is sectional drawing which shows an example of the process at the time of manufacturing the damping material of this invention. It is a table | surface which shows the structure, physical-property value, etc. of an Example and a comparative example.

Hereinafter, the damping material of the present invention will be described with reference to the drawings.
A vibration damping material 10 according to an embodiment of the present invention shown in FIG. 1 includes a core material 11 and a fiber-reinforced composite material 21 laminated on both surfaces of the core material 11, and a housing of a portable device such as a notebook computer. Used for.

  The damping material 10 has a plate shape with a predetermined size and thickness, and has a flexural modulus (JIS K7074-1988 A method) of 3 GPa or more, particularly preferably 10 GPa to 55 GPa, and a flexural strength (JISK7074-1988 A). Method) is 80 MPa or more, particularly preferably 100 MPa to 500 MPa. The bending elastic modulus is a physical property that serves as an index of rigidity. As the bending elastic modulus increases, the rigidity increases. In addition, when the damping material 10 is used as a casing of a portable device, so-called outsert molding is performed in which the damping material 10 is fixed and another member that becomes a side wall of the casing is injection-molded, The separate member is properly installed at a predetermined surface position.

The core material 11 is made of a thermosetting resin foam and is formed by being compressed when the vibration damping material 10 is manufactured.
The thermosetting resin foam is not particularly limited, and examples thereof include a silicon foam material, a urethane flexible foam material, a melamine resin, a polyimide resin, a phenol resin, and a bismaleimide triazine resin, and particularly an open cell structure. Polyurethane foam is preferred. As the polyurethane foam, those having a non-foamed skin layer on the surface or those having no non-foamed skin layer on the surface can be used. A polyurethane foam having a non-foamed skin layer on the surface can be produced by a mechanical foaming method. On the other hand, a polyurethane foam having no non-foamed skin layer on the surface can be produced by a slab foaming method.

  In the mechanical foaming method, a two-component reaction mixture forming a polyurethane foam is mechanically stirred by a Hobart mixer, an Oaks mixer, or the like, and an inert gas is uniformly dispersed in the reaction mixture at room temperature, thereby being stable. In this production method, bubbles are dispersed and formed in a reaction mixture, and the reaction mixture is discharged onto a belt conveyor to form a sheet, which is then heated and cured. When polyurethane foam manufactured by mechanical foaming is used to form a sheet by discharging and spreading the reaction mixture in which the bubbles are dispersed onto a belt conveyor, the bubbles are united on the front and back surfaces of the sheet-like body so that there is no foam. The skin layer (non-foamed layer) is formed.

When a polyurethane foam having a non-foamed skin layer on the surface is used as the thermosetting resin foam, the polyurethane foam has a density before lamination (JIS K) in order to obtain good vibration damping properties, light weight and rigidity. 6401) is preferably 150 to 500 kg / m ³ , tensile strength (JIS K 6251) is 0.2 to 5.0 MPa, and elongation (JIS K 6251) is preferably 70 to 200%. The polyurethane foam having a non-foamed skin layer on the surface preferably has a thickness before lamination of 0.5 to 6.0 mm.

  On the other hand, in the slab foaming method, a polyurethane foam raw material containing a foaming agent is continuously foamed by discharging it onto a belt conveyor at room temperature and atmospheric pressure with a low-pressure injection machine, and then sliced into a predetermined thickness and cut into sheets. The surface of the sliced polyurethane foam has a cellular structure exposed, and there is no non-foamed skin layer.

When a polyurethane foam having no non-foamed skin layer on the surface is used as the thermosetting resin foam, in order to obtain good vibration damping properties, light weight and rigidity, the density before lamination (JIS K 7222) is It is preferable that the tensile strength (JIS K 6251) is 150 to 700 kg / m ³ , the tensile strength (JIS K 6251) is 0.5 to 3.2 MPa, and the elongation (JIS K 6251) is 160 to 310%. The polyurethane foam having no non-foamed skin layer on the surface preferably has a thickness of 0.5 to 6.0 mm before lamination.

Moreover, it is preferable that the thermosetting resin foam which comprises the said core material 11 has the value of the fabric weight (density x thickness) before lamination | stacking of 50-500 g / m < ² >. If the basis weight before lamination of the thermosetting resin foam constituting the core material 11 is small, the amount of air due to air bubbles in the thermosetting resin foam is large, so the core material 11 is a hollow portion of the foam material. As the ratio increases, the strength decreases and the rigidity of the damping material 10 decreases. On the other hand, if the weight per unit area is large, the thermosetting resin foam cannot be sufficiently compressed with an average compression load, resulting in compression unevenness. As a result, an appropriate bending elastic modulus of the damping material 11 cannot be obtained, and thickness control becomes difficult.

  As shown in FIG. 2, the core material 11 is impregnated and cured with the resin impregnated in the fiber reinforced composite material 21 at the boundary surface 11 b with the fiber reinforced composite material 21. The core 11 and the fiber-reinforced composite material 21 are combined and integrated by the resin impregnation and hardening at the boundary surface 11 and the rigidity is increased. On the other hand, the central portion 11a of the core material 11 has a cell structure in which the resin of the fiber reinforced composite material 21 is not impregnated. The cell structure that is not impregnated with the resin in the central portion of the thickness of the core material 11 is the cell structure of the thermosetting resin foam used as the core material 11. By having a cell structure in which the resin 11 is not impregnated in the central thickness portion 11a of the core material 11, a vibration damping material having excellent vibration damping properties and light weight can be obtained.

  The fiber reinforced composite material 21 is obtained by impregnating a reinforced fiber with a resin and curing it. The one in which the reinforcing fibers are impregnated with a resin and in an uncured state is called a prepreg. Examples of the reinforcing fibers include uniaxially oriented products such as carbon fibers, glass fibers, silicon carbide fibers, metal fibers, alumina fibers, and aramid fibers, woven fabrics, and nonwoven fabrics. In particular, carbon fiber is preferable because it is excellent in light weight and high rigidity.

The resin to be impregnated into the reinforcing resin can be a thermosetting resin used as a resin for prepreg, and is not particularly limited. For example, a phenol resin, an epoxy resin, a vinyl ester resin, an unsaturated polyester resin, a polyurethane resin, a diallyl phthalate resin, and the like can be given.
When the damping material 10 is required to be flame retardant, the thermosetting resin is preferably flame retardant. Since phenol resin has good flame retardancy, it is suitable as a thermosetting resin impregnated in the reinforcing fiber fabric.

  The fiber reinforced composite material 21 may be laminated in one or more layers on both sides of the core material 11 and may be a plurality of layers. When the number of laminated fiber reinforced composite materials 21 increases, the rigidity of the damping material increases, while the weight of the damping material also increases. Therefore, the number of laminations is determined according to the rigidity and weight required for the damping material. Is done. Further, the number of stacked layers may be different on both sides of the core material 11, but the same number of stacked layers on both sides of the core material 11 is preferable in order to prevent warping.

  The damping material 10 preferably has a ratio of the thickness of the core material 11 to the thickness (total thickness) of the fiber-reinforced composite material 21 (that is, the thickness ratio of the core material) of 5 to 70%. That is, when the thickness (total thickness) of the fiber reinforced composite material 21 is represented by Tcf and the thickness of the core material 11 is represented by Tcr, the value of Tcr / Tcf × 100 is preferably 5 to 70 (%). When the thickness ratio of the core material is large, the thickness of the core material 11 made of the thermosetting resin foam is relatively large, and the vibration damping property indicated by the loss factor is excellent, while the rigidity is decreased. become. On the other hand, when the thickness ratio of the core material is small, the thickness of the core material 11 made of the thermosetting resin foam is relatively small, and the vibration damping property indicated by the loss factor is inferior. Will increase.

  A method for manufacturing the vibration damping material 10 will be described. An example of the manufacturing method of the vibration damping material 10 includes an impregnation step, a prepreg creation step, a lamination step, and a compression heating step.

  In the impregnation step, as shown in (3-1) of FIG. 3, the reinforcing fiber 210 is impregnated with the thermosetting resin 250, and the required number of reinforcing fibers 210A after impregnation is formed. The reinforcing fiber 210 and the thermosetting resin 250 are as described in the description of the vibration damping material 10. The thermosetting resin 250 used for impregnation is made of an uncured liquid. In order to facilitate the impregnation, the thermosetting resin 250 is preferably dissolved in a solvent. The impregnation means can be performed by an appropriate method such as a method of immersing the reinforcing fiber 210 in a tank containing the liquid thermosetting resin 250, a method of performing spraying, a method of performing using a roll coater, or the like.

  The amount of impregnation of the thermosetting resin 250 with respect to the reinforcing fiber 210 is preferably such that when the solvent is used, the amount of impregnation after removal of the solvent is 30 to 70 wt% as the resin ratio in the prepreg.

  In the prepreg preparation step, as shown in (3-2) of FIG. 3, the impregnated reinforcing fiber 210A obtained in the impregnation step is dried at a temperature at which the thermosetting resin is not cured to remove the solvent. A semi-cured prepreg 211 is created.

  In the laminating step, as shown in (3-3) of FIG. 3, the necessary number of the prepregs 211 is arranged on both surfaces of the thermosetting resin foam 110 to obtain the laminated body 101. The thermosetting resin foam 110 is as described in the description of the vibration damping material 10. The lamination operation is performed on the upper surface of the press molding lower mold 31 used in the compression heating step (3-4) to be performed next, the required number of the prepregs 211, the thermosetting resin foam 110, and the The required number of prepregs 211 may be stacked in that order. Further, the prepreg 211 and the thermosetting resin foam 110 preferably have the same plane size, but if they are different, they may be trimmed after the compression heating step described later.

  In the compression heating step, as shown in FIG. 3 (3-4), the laminate 101 is compressed and heated by the press mold lower mold 31 and the upper mold 33. The amount of compression is adjusted by the spacer 41 so that the thickness ratio (Tcr / Tcf × 100) of the core material is 5 to 70 (%). The spacer 41 is at an appropriate position of at least one of the lower mold 31 for press molding or the upper mold 33 so that a predetermined distance (predetermined compression thickness of the laminate) is provided between the lower mold 31 for press molding and the upper mold 33. Placed in. The thickness of the spacer 41 is equal to the thickness of the damping material 10 to be manufactured.

  The adjustment of the thickness ratio of the core material will be specifically described. Since the prepreg 211 has a configuration in which a reinforcing fiber is impregnated with a thermosetting resin, the prepreg 211 is not compressed by the compression in the compression heating step, and only the thermosetting resin foam 110 is compressed. Therefore, in the vibration damping material 10 obtained by the compression heating step, the thickness of the core material 11 is {(spacer thickness) − (total thickness of prepreg)}, and a plurality of the fiber-reinforced composite materials 21 are provided. The total thickness of the prepreg 211 is the total thickness of the prepreg 211. Therefore, the thickness ratio (Tcr / Tcf × 100) of the core material can be calculated by {(spacer thickness) − (total thickness of prepreg)} / (total thickness of prepreg) × 100. What is necessary is just to set the thickness of the said spacer 41 so that it may become a desired value in 5 to 70% of range.

  The heating method of the laminated body 101 is not particularly limited, and heating means such as a heater is provided in the lower mold 31 for press molding and the upper mold 33 and heated via the lower mold 31 for press molding and the upper mold 33. It's easy. The heating temperature is set to be equal to or higher than the curing reaction temperature of the impregnated thermosetting resin.

  In the compression heating process, when the laminate 101 is heated and compressed, a thermosetting resin is extruded from the prepreg 211 at the boundary surface between the prepreg 211 and the thermosetting resin foam 110, so that the thermosetting is performed. The resin foam 110 is impregnated on both surfaces. At that time, by adjusting the compression so that the core thickness ratio (Tcr / Tcf × 100) is 5 to 70 (%), the thermosetting resin foam 110 has at least a central portion. It is not compressed. As a result, the thermosetting resin extruded from the prepreg 211 is not impregnated to the central portion in the thickness direction of the thermosetting resin foam 110, and in the central thickness portion of the thermosetting resin foam 110, A bubble structure that is not impregnated with the thermosetting resin remains.

  In addition, when a plurality of the prepregs 211 are arranged on both sides of the thermosetting resin foam 110, the thermosetting resin is pushed out from the prepreg 211 at the boundary surface between the prepregs 211, and the other side in contact with each other The prepreg 211 is impregnated.

  The thermosetting resin starts a curing reaction by heating and is cured in a state where the laminate 101 is compressed. The core material 11 is formed from the thermosetting resin foam 110, and the fiber reinforced composite material 21 after curing is formed from the prepreg 211. The core material 11, the fiber reinforced composite material 21, and the core When a plurality of fiber reinforced composite materials 21 are laminated on both sides of the material 11, the fiber reinforced composite materials 21 are also integrated with each other to form the vibration damping material 10. Thereafter, the heat compression is released to obtain the vibration damping material 10.

In the impregnation step, the reinforcing fiber 210 may be impregnated with the thermosetting resin 250, and both surfaces of the thermosetting resin foam 110 for the core material 11 may be impregnated with the thermosetting resin 250. Good.
Alternatively, the lamination step and the compression heating step may be sequentially performed using the reinforced fiber after impregnation obtained in the impregnation step without performing the prepreg preparation step after the impregnation step.

Example 1
Phenol resin solution (manufactured by Sumitomo Bakelite Co., Ltd., product name: PR-55791B, resin concentration 60 wt% ethanol solution) as a thermosetting resin, and twill carbon fiber fabric (manufactured by Toho Tenax Co., Ltd., product name) as a reinforcing fiber; W-3161 , Fiber weight 200 g / m ² ) was soaked and taken out, and then naturally dried at room temperature of 25 ° C. for 2 hours, and further dried at 60 ° C. for 1 hour to prepare four prepregs. The carbon fiber fabric used was cut into a plane size of 200 × 350 mm (weight 14 g / sheet). The prepreg after drying was 32 g per sheet.

As a thermosetting resin foam for the core material, polyurethane foam produced by a mechanical foaming method (Roger Suinoac Co., Ltd., product name: PRON MX-48HF, thickness 0.6 mm, density 480 kg / m ³ , with skin layer, Impregnating one sheet (weight 20 g / sheet) obtained by cutting a tensile strength of 4.24 MPa (JIS K 6251), elongation 80% (JIS K 6251), basis weight 288 g / m ² into a plane size of 200 × 350 mm. We used without.

  Next, two prepregs, one thermosetting resin foam, and two prepregs in this order on a lower mold (flat plate) made of SUS with a release agent applied on the surface in advance. By laminating them, a laminate in which two prepregs were arranged on both sides of the thermosetting resin foam was set on the lower mold for press molding.

  In a state where the laminate is set on the lower mold for press molding, a pressure of 10 MPa is applied at 150 ° C. for 10 minutes to press the laminate with the upper mold for press molding (flat plate shape), and compression and heating are performed. The phenolic resin was reaction-cured in the compressed state. At that time, the laminate was heated by a casting heater attached to the upper and lower press dies. In addition, a SUS spacer having a thickness of 1.5 mm was interposed between the lower mold for press molding and the upper mold to adjust the distance between the lower mold and the upper mold, that is, the compression thickness of the laminate (the thickness of the damping material). . Thereafter, the lower mold and upper mold for press molding were cooled at room temperature, and then the lower mold and upper mold were opened to obtain a vibration damping material of Example 1 in which fiber-reinforced composite materials were laminated and integrated on both surfaces of the core material.

Example 2
A damping material of Example 2 was prepared in the same manner as in Example 1 except that the spacer in Example 1 was 1.6 mm in thickness.

Example 3
Except for preparing six prepregs in Example 1 and placing three prepregs on both sides of the thermosetting resin foam, and setting the spacer thickness to 2.0 mm, the control of Example 3 was performed. A vibration material was created.

Example 4
The thermosetting resin foam for the core material in Example 3 having a thickness of 1.0 mm (weight 33.6 g / sheet) (product name, density, skin layer presence, tensile strength, elongation) is the same as in Example 3. The vibration damping material of Example 4 was created in the same manner as in Example 3 except for the above.

Example 5
As a thermosetting resin foam for the core material, polyurethane foam of slab foam (manufactured by INOAC CORPORATION, product name; cell damper-BF-150, thickness 0.5 mm, density 150 kg / m ³ , no skin layer, tensile strength 0 .8 MPa, elongation 220%) was cut into a plane size of 200 × 350 mm (weight: 5.2 g / sheet), and the spacer thickness was 1.6 mm. The vibration damping material of Example 5 was created.

Example 6
A damping material of Example 6 was prepared in the same manner as Example 5 except that the thickness of the spacer was 1.7 mm.

-Example 7
As a thermosetting resin foam for the core material, polyurethane foam of slab foam (manufactured by Inoac Corporation, product name; cell damper-BF-300, thickness 0.5 mm, density 300 kg / m ³ , no skin layer, tensile strength 1 .3 MPa, elongation 310%) was cut into a plane size of 200 × 350 mm (weight: 10.5 g / sheet) without impregnation, and the thickness of the spacer was 2.0 mm In the same manner as in Example 5, the vibration damping material of Example 7 was prepared.

Example 8
As a thermosetting resin foam for the core material, polyurethane foam of slab foam (manufactured by INOAC CORPORATION, product name: UGR, thickness 0.9 mm, density 60 kg / m ³ , no skin layer, tensile strength 0.5 MPa, elongation 180%) was cut into a plane size of 200 × 350 mm (weight: 3.8 g / sheet), and was used without impregnation. The vibration damping material of Example 8 was the same as Example 7. Created.

Example 9
Ten prepregs in Example 7 were prepared, and the thermosetting resin foam for the core material had a thickness of 1.0 mm (weight 21 g / sheet) (product name, density, no skin layer, tensile strength, elongation) The vibration damping of Example 9 is the same as Example 7 except that five prepregs are arranged on both sides of the thermosetting resin foam and the spacer thickness is 3.0 mm. Made the material.

Example 10
As the thermosetting resin foam for the core material, polyurethane foam of mechanical foam (Roger Sinoac Co., Ltd., product name: PRON NU-60, thickness 0.7 mm, density 600 kg / m ³ , skin layer existence, tensile strength 1. One 30 MPa (JIS K 6251), 150% elongation (JIS K 6251) cut into a plane size of 200 × 350 mm (weight 29.4 g / sheet) is used without impregnation, and the thickness of the spacer is 1 A damping material of Example 10 was prepared in the same manner as in Example 1 except that the thickness was 0.7 mm.

Example 11
As a thermosetting resin foam for the core material, polyurethane foam of slab foam (manufactured by Inoac Corporation, product name: MF50, thickness 1.5 mm, density 30 kg / m ³ , no skin layer, tensile strength 150 MPa, elongation 200% ) Was cut into a plane size of 200 × 350 mm (weight: 3.1 g / sheet) and used without impregnation, a damping material of Example 11 was prepared in the same manner as Example 3. .

Example 12
The thermosetting resin foam for the core material in Example 3 has a thickness of 1.1 mm (weight 37 g / sheet) (product name, density, skin layer presence, tensile strength, elongation are the same as in Example 3). A damping material of Example 12 was prepared in the same manner as Example 3 except that the thickness of the spacer was 2.4 mm.

Comparative example 1
In place of the thermosetting resin foam for the core material in Example 1, a melamine resin foam (manufactured by BASF, product name: Basotect G, thickness 5.0 mm, density 9 kg / m ³ , no skin layer, tensile strength 148 KPa The vibration damping material of Comparative Example 1 was prepared in the same manner as in Example 1 except that a material obtained by impregnating and drying phenol resin in advance was used.

Comparative example 2
Six prepregs prepared in the same manner as in Example 1 were stacked and set on the lower mold for press molding, the thickness of the spacer was 1.5 mm, and a surface pressure of 10 MPa was applied at 150 ° C. for 10 minutes for press molding. Pressing with an upper mold (flat plate), compression and heating were performed, and the phenolic resin was reacted and cured to prepare a vibration damping material of Comparative Example 2.

  About the damping material of each example and each comparative example, the thickness of the damping material, the thickness of all layers of the fiber-reinforced composite material, the thickness of the core material, the thickness ratio of the core material, the specific gravity, the thickness of the core material The cell structure, loss factor, flexural strength, and flexural modulus were measured or judged. The results are shown in the table of FIG.

The thickness of the damping material was measured with a micrometer.
The thickness (Tcf) of all layers of the fiber reinforced composite material is a value obtained by multiplying the thickness (measured with a micrometer) of the fiber reinforced composite material layer by the number of sheets used.
The thickness (Tcr) of the core material was calculated by subtracting the entire thickness of the fiber reinforced composite material from the thickness of the damping material.
The thickness ratio (%) of the core material was calculated by Tcr / Tcf × 100.
Specific gravity is a value obtained by cutting a damping material into 5 cm square and dividing the weight by volume.
The bubble structure at the center of the thickness of the core material was obtained by cutting the damping material and observing the cross section with a digital microscope manufactured by Keyence Corporation. It was observed and judged whether or not a bubble structure not impregnated with a thermosetting resin was formed in the central portion of the core material. At the same time, the presence of a layer in which the thermosetting resin was solidified was observed and judged on the interface between the core material and the fiber-reinforced composite material. The result is that when there is a cell structure in which the thermosetting resin is solidified at the interface between the core material and the fiber-reinforced composite material, and the thermosetting resin cannot be observed at the thickness center of the core material, “O”, and “x” when the presence of the thermosetting resin can be confirmed up to the center of the thickness of the core material.
Also. The overall evaluation is “◎” when the flexural modulus is 10 GPa or more and the loss coefficient is 0.03 or more, “◯” when the flexural modulus is 3 GPa or more and the loss coefficient is 0.03 or more, and the loss coefficient is smaller than 0.03. In this case, “x” was assigned.

The loss factor was measured in accordance with JIS K 7391: 2008 (vibration damping characteristic test method for unconstrained vibration-damping composite beams) according to the central excitation method (by sweeping vibration, but without zoom analysis / mass cancellation). Sample size 25 × 300 mm). The greater the loss factor value, the higher the damping performance.
The bending strength was measured according to JIS K7074-1988 A method.
The flexural modulus was measured according to JIS K 7074-1988 A method. The flexural modulus is a physical property value that serves as an index of stiffness. The greater the flexural modulus value, the higher the stiffness.

  In Example 1, the core material has a thermosetting resin foam having a skin layer on the surface, the thickness of the core material (thermosetting resin foam) before lamination integration is 0.6 mm, and the number of laminated fiber reinforced composite materials 4, the thickness of the damping material is 1.5 mm, the thermosetting resin is impregnated and hardened on the boundary surface of the core material, the cell structure in which the center of the core material is not impregnated with the thermosetting resin, the specific gravity of the damping material 1.11, a loss factor of 0.1160, a bending strength of 180 MPa, a bending elastic modulus of 12.4 GPa, light weight, excellent vibration damping properties, and high rigidity.

  In Example 2, the core material is a thermosetting resin foam having a skin layer on the surface, the core material before lamination integration (thermosetting resin foam) has a thickness of 0.6 mm, and the number of laminated fiber reinforced composite materials 4, the thickness of the damping material is 1.6 mm, the thermosetting resin is impregnated and hardened on the boundary surface of the core material, the cell structure is not impregnated with the thermosetting resin, and the specific gravity of the damping material 1.14, loss factor 0.0633, flexural strength 115 MPa, flexural modulus 10.5 GPa, light weight, good vibration damping properties, and high rigidity.

  In Example 3, the core material has a thermosetting resin foam having a skin layer on the surface, the thickness of the core material (thermosetting resin foam) before lamination integration is 0.6 mm, and the number of laminated fiber reinforced composite materials 6, the thickness of the damping material is 2.0 mm, the thermosetting resin is impregnated and hardened on the boundary surface of the core material, the cell structure in which the center of the core material is not impregnated with the thermosetting resin, the specific gravity of the damping material 1.35, a loss factor of 0.0602, a bending strength of 217 MPa, a bending elastic modulus of 14.3 GPa, light weight, good vibration damping properties, and high rigidity.

  In Example 4, the thermosetting resin foam whose core material has a skin layer on the surface, the thickness of the core material (thermosetting resin foam) before lamination integration is 1.0 mm, and the number of laminated fiber reinforced composite materials 6, the thickness of the damping material is 2.0 mm, the thermosetting resin is impregnated and hardened on the boundary surface of the core material, the cell structure in which the center of the core material is not impregnated with the thermosetting resin, the specific gravity of the damping material 1.30, a loss factor of 0.0332, a bending strength of 110 MPa, a bending elastic modulus of 10.2 GPa, light weight, good vibration damping properties, and high rigidity.

  In Example 5, the core material is a thermosetting resin foam having no skin layer on the surface, the thickness of the core material (thermosetting resin foam) before lamination integration is 0.5 mm, and the number of laminated fiber reinforced composite materials 6, the thickness of the damping material is 1.6 mm, the thermosetting resin is impregnated and hardened on the boundary surface of the core material, the cell structure is not impregnated with the thermosetting resin, and the specific gravity of the damping material 1.40, a loss factor of 0.0305, a bending strength of 476 MPa, a flexural modulus of 40.2 GPa, light weight, good vibration damping properties, and high rigidity.

  In Example 6, the core material has a thermosetting resin foam without a skin layer on the surface, the core material before lamination integration (thermosetting resin foam) has a thickness of 0.5 mm, and the number of laminated fiber reinforced composite materials 6, the thickness of the damping material is 1.7 mm, the thermosetting resin is impregnated and hardened on the boundary surface of the core material, the cell structure in which the center of the core material is not impregnated with the thermosetting resin, the specific gravity of the damping material Is 1.40, loss factor is 0.0713, bending strength is 408 MPa, bending elastic modulus is 38.2 GPa, light weight, good vibration damping property, and high rigidity.

  In Example 7, the core material is a thermosetting resin foam having no skin layer on the surface, the thickness of the core material (thermosetting resin foam) before lamination integration is 0.5 mm, and the number of laminated fiber reinforced composite materials 6, the thickness of the damping material is 2.0 mm, the thermosetting resin is impregnated and hardened on the boundary surface of the core material, the cell structure in which the center of the core material is not impregnated with the thermosetting resin, the specific gravity of the damping material Is 1.22, loss factor is 0.1777, bending strength is 180 MPa, bending elastic modulus is 12.5 GPa, and it is excellent in light weight, vibration damping property and rigidity.

  In Example 8, the core material is a thermosetting resin foam having no skin layer on the surface, the thickness of the core material (thermosetting resin foam) before lamination integration is 0.9 mm, and the number of laminated fiber reinforced composite materials 6, the thickness of the damping material is 2.0 mm, the thermosetting resin is impregnated and hardened on the boundary surface of the core material, the cell structure in which the center of the core material is not impregnated with the thermosetting resin, the specific gravity of the damping material 1.29, a loss factor of 0.0590, a bending strength of 175 MPa, a bending elastic modulus of 11.2 GPa, light weight, good vibration damping properties, and high rigidity.

  In Example 9, the core material is a thermosetting resin foam having no skin layer on the surface, the core material before lamination integration (thermosetting resin foam) has a thickness of 1.0 mm, and the number of laminated fiber reinforced composite materials 10, the thickness of the damping material is 3.0 mm, the thermosetting resin is impregnated and cured on the boundary surface of the core material, the cell structure is not impregnated with the thermosetting resin, and the specific gravity of the damping material 1.35, a loss factor of 0.0561, a bending strength of 305 MPa, a bending elastic modulus of 23.7 GPa, light weight, good vibration damping properties, and high rigidity.

  In Example 10, the thermosetting resin foam whose core material has a skin layer on the surface, the thickness of the core material (thermosetting resin foam) before lamination integration is 0.7 mm, and the number of laminated fiber reinforced composite materials 4, the thickness of the damping material is 1.7 mm, the thermosetting resin is impregnated and hardened on the boundary surface of the core material, the cell structure in which the center of the core material is not impregnated with the thermosetting resin, the specific gravity of the damping material 1.14, loss coefficient is 0.3290, bending strength is 81 MPa, bending elastic modulus is 3.3 GPa and is excellent in light weight and vibration damping properties, but the rigidity is lower than those in Examples 1 to 9. It is.

  In Example 11, the core material is a thermosetting resin foam having no skin layer on the surface, the thickness of the core material (thermosetting resin foam) before lamination integration is 1.5 mm, and the number of laminated fiber reinforced composite materials 6, the thickness of the damping material is 2.0 mm, the thermosetting resin is impregnated and hardened on the boundary surface of the core material, the cell structure is not impregnated with the thermosetting resin, and the specific gravity of the damping material is 1.27, loss factor is 0.1413, bending strength is 92 MPa, bending elastic modulus is 4.8 GPa and is excellent in light weight and vibration damping properties, but the rigidity is lower than those in Examples 1-9. is there.

  In Example 12, the core material has a thermosetting resin foam having a skin layer on the surface, the thickness of the core material (thermosetting resin foam) before lamination integration is 1.1 mm, and the number of laminated fiber reinforced composite materials 6, the thickness of the damping material is 2.4 mm, the thermosetting resin is impregnated and hardened on the boundary surface of the core material, the cell structure in the center of the core material is not impregnated with the thermosetting resin, the specific gravity of the damping material 1.32, loss coefficient is 0.1360, bending strength is 89 MPa, bending elastic modulus is 3.5 GPa, and is excellent in light weight and vibration damping properties, but the rigidity is lower than those in Examples 1 to 9. It is.

  In Comparative Example 1, the core material is a melamine resin foam, the thickness of the core material (thermosetting resin foam) before lamination integration is 5.0 mm, the number of laminated fiber reinforced composite materials is 4, the thickness of the damping material Is 1.5 mm, thermosetting resin is impregnated to the center of the core thickness, the specific gravity of the damping material is 1.38, the loss factor is 0.0081, the bending strength is 412 MPa, and the flexural modulus is 46.0 GPa. It is inferior to the vibration damping property, and the rigidity is higher than those of Examples 1-12.

  Comparative Example 2 is composed of only six layers of fiber reinforced composite material, the thickness of the damping material is 1.5 mm, the specific gravity is 1.57, the loss factor is 0.0031, the bending strength is 451 MPa, and the flexural modulus is 50. 0.0 GPa, inferior in vibration damping properties, and higher in rigidity than Examples 1-12.

  Thus, the vibration damping material of the present invention has good vibration damping properties, light weight, and rigidity, and is suitable as a material for a case of a portable OA device that requires vibration damping properties, light weight, and rigidity. .

DESCRIPTION OF SYMBOLS 10 Damping material 11 Core material 11a Thickness center part of core material 11b Boundary surface with fiber reinforced composite material of core material 21 Fiber reinforced composite material 101 Laminated body 210 Reinforcing fiber before impregnation 210A Reinforcing fiber after impregnation 211 Prepreg 250 Heat Curable resin 31 Lower mold for press molding 33 Upper mold for press molding 41 Spacer

Claims (5)

In the damping material in which the fiber reinforced composite material is laminated on both sides of the core material,
The core material is made of a thermosetting resin foam, and the core material and the fiber reinforced composite are formed by a resin impregnated in the fiber reinforced composite material at a boundary surface between the core material and the fiber reinforced composite material. A vibration damping material, wherein the material is bonded and solidified, and has a cell structure that is not impregnated with the resin at a central portion of the core material. The thermosetting resin foam is a polyurethane foam having a non-foamed skin layer on the surface, and has a density (JIS K 6401) before lamination of 150 to 500 kg / m ³ and a tensile strength (JIS K 6251). The damping material according to claim 1, wherein the damping material is 0.2 to 5.0 MPa and elongation (JIS K 6251) is 70 to 200%. The thermosetting resin foam is a polyurethane foam having no non-foamed skin layer on the surface, the density before lamination (JIS K 6401) is 150 to 700 kg / m ³ , and the tensile strength (JIS K 6251). The damping material according to claim 1, wherein 0.5 to 3.2 MPa and elongation (JIS K 6251) is 160 to 310%.   The damping material according to any one of claims 1 to 3, wherein a ratio of the thickness of the core material to the thickness of the fiber-reinforced composite material in the damping material is 5 to 70%. 5. The vibration damping material according to claim 4, wherein a basis weight of the thermosetting resin foam constituting the core material before the lamination is 50 to 500 g / m ² .

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