JP2020090070A - Reinforcing sheet and reinforcing structure - Google Patents

Abstract

To provide a reinforcing sheet and a reinforcing structure that have excellent bending strength and can prevent warping of a panel.SOLUTION: A reinforcing sheet that is to be stuck onto a metal panel. The reinforcing sheet comprises a foamable resin layer 3 that contains a foamer and has a monolayer structure, and a metal layer 4 disposed on one side of the foamable resin layer 3 in the thickness direction, and has a large through hole 2 that penetrates in the thickness direction.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a reinforcing sheet and a reinforcing structure, and more particularly to a reinforcing sheet that is attached to various industrial products to reinforce the product, and a reinforcing structure using the reinforcing sheet.

BACKGROUND ART It has been conventionally known that a reinforcing sheet is attached to a metal panel of a transportation device or the like to reinforce a mounting structure such as a transportation device such as an automobile, a railroad vehicle, a ship or an airplane, or a home door. (For example, refer to Patent Document 1).

Patent Document 1 describes a steel plate reinforcing sheet including a resin layer made of a resin composition for reinforcing steel plate containing an epoxy resin, acrylonitrile-butadiene rubber, a curing agent and a foaming agent, and a constraining layer made of glass cloth. There is.

In the reinforcing sheet described in Patent Document 1, a resin layer is foamed by heating at a high temperature and attached to an adherend (steel plate). In this reinforcing sheet, the flexural strength is improved because the resin layer is thickened by foaming.

JP, 2005-139218, A

However, in the reinforcing sheet of Patent Document 1, since the glass cloth is arranged on the upper surface of the resin layer, the gas generated from the foaming agent permeates the glass cloth when the resin layer is foamed. As a result, the desired thickness is not achieved and the bending strength decreases.

Further, in the reinforcing sheet of Patent Document 1, the resin layer contracts or expands in the surface direction during heat curing, which causes distortion in the metal panel. In recent years, in particular, in order to reduce the weight, an aluminum plate or a thin steel plate may be used as a metal panel instead of a steel plate, and such a metal panel is particularly likely to be distorted.

An object of the present invention is to provide a reinforcing sheet and a reinforcing structure that have excellent bending strength and can suppress panel distortion.

The present invention [1] is a reinforcing sheet attached to a panel, comprising a foaming resin layer containing a foaming agent and comprising a single layer, and a metal layer arranged on one side in the thickness direction of the foaming resin layer. And a reinforcing sheet having a through hole penetrating the reinforcing sheet in the thickness direction.

The present invention [2] includes the reinforcing sheet according to [1], wherein the linear thermal expansion coefficient of the metal layer is 5×10 ⁻⁶ or more and 30×10 ⁻⁶ or less.

The present invention [3] includes the reinforcing sheet according to [1] or [2], wherein the metal layer has a thickness of 0.01 mm or more and 3 mm or less.

This invention [4] is a ratio of the planar view area of the said through-hole with respect to the planar view area of the said reinforcement sheet, and is 10% or more and 80% or less, It is described in any one of [1]-[3]. Includes a reinforcing sheet.

The present invention [5] includes the reinforcing sheet according to any one of [1] to [4], wherein the through-hole has a substantially elliptical shape or a substantially circular shape.

The present invention [6] includes the reinforcing sheet according to any one of [1] to [5], wherein the through hole is formed at least in a central region.

The present invention [7] includes the reinforcing sheet according to any one of [1] to [6], wherein the panel is a metal panel.

The present invention [8] is a reinforcing structure comprising a panel and a reinforcing sheet arranged on one side in the thickness direction of the panel, wherein the reinforcing sheet is arranged on one side in the thickness direction of the panel, The reinforcing sheet includes a foam layer composed of a layer and a metal layer arranged on one side in the thickness direction of the foam layer, and the reinforcing sheet includes a reinforcing structure having a through hole penetrating in the thickness direction.

The present invention [9] includes the reinforcing structure according to [8], wherein the panel is a metal panel.

In the present invention [10], the ratio (C ₂ /C ₁ ) of the linear thermal expansion coefficient C ₂ of the panel to the linear thermal expansion coefficient C ₁ of the metal layer is 0.4 or more and 3 or less. The reinforcing structure according to [8] or [9] is included.

According to the reinforcing sheet of the present invention, the foaming resin layer contains a foaming agent and comprises a single layer of the foaming resin layer and a metal layer arranged on one side in the thickness direction of the foaming resin layer, so that the foaming resin layer is When foaming, gas from the foaming agent can be prevented from passing through the metal layer. Therefore, the foamable resin layer has excellent foamability, and a foam layer having a desired thickness can be obtained. Therefore, the bending strength of the reinforcing sheet is excellent.

Moreover, since the reinforcing sheet has the through holes, it is possible to suppress distortion of the panel.

The reinforcing structure of the present invention has improved strength while suppressing distortion.

1A-B is a reinforcing sheet of one embodiment of the present invention, FIG. 1A is a plan view, and FIG. 1B is a sectional view taken along line AA of FIG. 1A. 2A-B are process diagrams of manufacturing a metal panel structure using the reinforcing sheet shown in FIG. 1, FIG. 2A is a process of arranging the reinforcing sheet on the metal panel, and FIG. 2B is foaming of the reinforcing sheet. The process of doing is shown. FIG. 3 shows a modification of the embodiment of the reinforcing sheet (a form in which the through holes are circular). FIG. 4 shows a modification of the embodiment of the reinforcing sheet (a form in which a plurality of through holes are formed only in the central region). FIG. 5 shows a modification of the embodiment of the reinforcing sheet (a form in which a plurality of through holes extending in the first direction are formed). FIG. 6 shows a modification of the embodiment of the reinforcing sheet (a form in which a plurality of through holes are formed in the central region and the outer region). FIG. 7 shows a modification of the embodiment of the reinforcing sheet (the outer shape of the reinforcing sheet is elliptical). FIGS. 8A-B are schematic views when carrying out a strain test, FIG. 8A shows a plan view, and FIG. 8B shows a bottom view.

In FIG. 1A, the vertical direction of the paper is the first direction, the upper side of the paper is one side in the first direction, and the lower side of the paper is the other side in the first direction. The left-right direction of the paper is the second direction (direction orthogonal to the first direction), the left side of the paper is one side in the second direction, and the right side of the paper is the other side in the second direction. The paper thickness direction is the third direction (direction orthogonal to the first direction and the second direction), the front side of the paper surface is one side in the third direction (one side in the thickness direction), and the back side of the paper surface is the other side in the third direction (thickness direction). The other side). The other drawings also follow the direction of FIG. 1A.

<First Embodiment>
1. Reinforcement Sheet As shown in FIG. 1A, the reinforcement sheet 1 which is an embodiment of the first embodiment of the present invention has a sheet shape extending in the plane direction (first direction and second direction).

When viewed from the thickness direction (in plan view), the reinforcing sheet 1 has a substantially rectangular outer shape that is long in the second direction (one example of the plane direction).

The reinforcing sheet 1 is symmetrical in the first direction (vertical symmetry on the paper surface of FIG. 1A) and second symmetric (horizontal symmetry on the paper surface of FIG. 1A).

The reinforcing sheet 1 has one large through hole 2 (an example of a through hole) in the central region 9. The large through hole 2 penetrates the reinforcing sheet 1 in the thickness direction (third direction), as shown in FIG. 1B. The large through hole 2 is included in the central region 9.

The large through hole 2 has a substantially elliptical shape elongated in the second direction. The large through hole 2 overlaps with the center C of the reinforcing sheet 1 when projected in the thickness direction, and the center of the large through hole 2 coincides with the center C of the reinforcing sheet 1.

The central region 9 is a range of a similar shape (rectangular shape) having an area of 50% (preferably 30%) with respect to the plan view area of the reinforcing sheet 1 with the center C of the reinforcing sheet 1 as the center of the central region. (See the phantom line in FIG. 1A). The center C of the reinforcing sheet 1 is the center of gravity of the reinforcing sheet 1 when the reinforcing sheet 1 is assumed to be a uniform material.

The area in plan view of the reinforcing sheet 1 (the area surrounded by the outer shape of the reinforcing sheet 1 and including the area of the large through-hole 2) is, for example, 25 cm ² or more, preferably 200 cm ² or more, and more preferably , and at 400 cm ² or more, and is, for example, 6000 cm ² or less, preferably, 4500Cm ² or less, more preferably 3200 cm ² or less.

The first direction length (shorter direction length) L1 of the reinforcing sheet 1 is, for example, 5 cm or more, preferably 10 cm or more, more preferably 15 cm or more, and, for example, 60 cm or less, preferably 50 cm. The following is more preferably 40 cm or less.

The second direction length (longitudinal length) L2 of the reinforcing sheet 1 is, for example, 5 cm or more, preferably 20 cm or more, more preferably 30 cm or more, and for example, 100 cm or less, preferably 90 cm or less. , And more preferably 80 cm or less.

The ratio of the plan view area of the large through hole 2 to the plan view area of the reinforcing sheet 1 is, for example, 5% or more, preferably 10% or more, more preferably 20% or more, and, for example, 90% or less. It is preferably 80% or less, more preferably 70% or less, still more preferably 40% or less.

When the area ratio and the length are within the above ranges, the distortion of the panel can be suppressed uniformly.

As shown in FIG. 1B, the reinforcing sheet 1 includes a foamable resin layer 3 and a metal layer 4 arranged on one side in the thickness direction of the foamable resin layer 3. That is, the reinforcing sheet 1 includes the foamable resin layer 3 and the metal layer 4 in the thickness direction.

The foamable resin layer 3 is an adhesive layer for adhering the reinforcing sheet 1 to an adherend. The foamable resin layer 3 forms the outer shape of the reinforcing sheet 1 and is formed in a sheet shape extending in the first direction and the second direction. The foamable resin layer 3 is composed of a single layer. Therefore, the foamable resin layer 3 can be uniformly foamed to form the foam layer 13 composed of a single layer, and the bending strength of the reinforcing sheet 1 can be reliably improved.

The foamable resin layer 3 contains a resin and a foaming agent. Therefore, it is possible to increase the thickness of the foamable resin layer 3 by foaming and reliably improve the bending strength of the reinforcing sheet 1.

The foamable resin layer 3 is formed from a foamable resin composition containing a resin and a foaming agent.

The resin is preferably a thermosetting resin. Thereby, the foamable resin layer 3 can have thermosetting property. Therefore, the reinforcing sheet 1 can be reliably attached to the metal panel (adherend) by heating and firmly fixed.

Examples of the thermosetting resin include epoxy resin. Examples of the epoxy resin include aromatic epoxy resins such as bisphenol type epoxy resin (for example, bisphenol A type epoxy resin), novolac type epoxy resin (for example, phenol novolac type epoxy resin), and naphthalene type epoxy resin, for example, , Nitrogen-containing cyclic epoxy resin such as triepoxypropyl isocyanurate resin, for example, aliphatic epoxy resin, alicyclic epoxy resin (for example, dicyclo cyclic epoxy resin), glycidyl ether type epoxy resin, glycidyl ester type epoxy resin , Glycidyl amine type epoxy resin and the like. Preferred is a bisphenol type epoxy resin.

The foaming agent is a heating foaming agent that foams by heating, and examples thereof include an inorganic foaming agent and an organic foaming agent.

Examples of the inorganic foaming agent include ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride, and azides.

Examples of the organic foaming agent include N-nitroso compounds (N,N'-dinitrosopentamethylenetetramine, etc.), azo compounds (azobisisobutyronitrile, etc.), fluorinated alkanes (trichloromonofluoromethane, etc.). ), hydrazine compounds (4,4′-oxybis(benzenesulfonylhydrazide), etc.), allylbis(sulfonylhydrazide), etc., semicarbazide compounds (p-toluylenesulfonylsemicarbazide, etc.), triazole compounds (5-morpholyl-1) , 2,3,4-thiatriazole, etc.) and the like. Preferred is 4,4'-oxybis(benzenesulfonyl hydrazide) (OBSH).

The blending ratio of the foaming agent is, for example, 0.1 parts by mass or more, preferably 0.5 parts by mass or more, and for example, 20 parts by mass or less, preferably 5 parts by mass or less, relative to 100 parts by mass of the resin. Is.

The foamable resin composition preferably further contains rubber. Thereby, the foamable resin layer 3 can be provided with flexibility. The foamable resin layer 3 is preferably a foamable thermosetting elastic resin layer. If the foamable resin layer 3 is an elastic layer, the distortion of the metal panel can be further suppressed.

Examples of the rubber include styrene/butadiene rubber (SBR), acrylonitrile/butadiene rubber (NBR), isoprene rubber, and butadiene rubber. Preferably, a combination of NBR and polybutadiene rubber is used.

The compounding ratio of the rubber is, for example, 10 parts by mass or more, preferably 20 parts by mass or more, preferably 40 parts by mass or more, and for example, 500 parts by mass or less, relative to 100 parts by mass of the resin. Is 300 parts by mass or less, preferably 100 parts by mass or less.

Further, in the foamable resin composition, in addition to the above components, an additive such as a tackifier, a filler, an epoxy resin curing agent, a vulcanizing agent, a vulcanization accelerator, a pigment, and a thixo agent in an appropriate ratio. It can also be added.

The thickness of the foamable resin layer 3 (before foaming) is, for example, 0.1 mm or more, preferably 0.2 mm or more, and for example, 10 mm or less, preferably 5 mm or less.

The metal layer 4 is a constraining layer for constraining the expandable resin layer 3 (or the foam layer 13 described later) and imparting toughness to the expandable resin layer 3 to improve the strength. The metal layer 4 is laminated on the upper surface of the foamable resin layer 3. The metal layer 4 is formed in a sheet shape that forms the outer shape of the reinforcing sheet 1, and specifically, the metal layer 4 is formed in the same shape as the foamable resin layer 3 in a plan view. That is, the outer peripheral edge of the metal layer 4 is flush with the outer peripheral edge of the foamable resin layer 3 in the thickness direction, and the inner peripheral edge of the metal layer 4 (the peripheral edge of the large through hole 2). Are flush with the inner peripheral edge of the foamable resin layer 3 in the thickness direction.

Examples of the metal layer 4 include aluminum foil and steel foil.

The linear thermal expansion coefficient C ₁ of the metal layer 4 is, for example, 5×10 ⁻⁶ or more, preferably 7×10 ⁻⁶ or more, more preferably 10×10 ⁻⁶ or more, and, for example, 30×. It is 10 ⁻⁶ or less, preferably 25×10 ⁻⁶ or less.

The thickness of the metal layer 4 is, for example, 0.01 mm or more, preferably 0.05 mm or more, and for example, 3 mm or less, preferably 1 mm or less.

The reinforcing sheet 1 is obtained by producing a laminated body of the metal layer 4 and the foamable resin layer 3, and performing outer shape processing of the laminated body and formation of through holes by punching, Thomson processing, laser processing, or the like. .. The laminate can be obtained by the method described in JP 2010-56112 A or the like.

2. Usage of Reinforcing Sheet The reinforcing sheet 1 is used to reinforce a panel, and specifically, for example, a transportation device panel (part) that constitutes a transportation device such as an automobile, a railroad vehicle, a ship, an airplane, for example, It is used to reinforce mounting equipment panels (parts) that compose mounting structures such as platform doors.

Examples of the transportation equipment panel include door panels, roof panels, fenders, bonnets, bumpers, etc. for automotive applications.

The machine component panel and the attachment device panel are panels, and preferably metal panels. Examples of the metal panel include an aluminum plate, a steel plate, a copper plate, a zinc plate, and a brass plate. From the viewpoint of weight reduction, an aluminum plate is preferable.

The thickness of the panel is, for example, 2 mm or less, preferably 1.5 mm or less, and for example, 0.1 mm or more.

An embodiment of a method for reinforcing a panel using the reinforcing sheet 1 will be described with reference to FIGS. 2A to 2B.

First, as shown in FIG. 2A, the reinforcing sheet 1 is arranged on one side in the thickness direction of the metal panel 5. Specifically, the other surface in the thickness direction of the foamable resin layer 3 of the reinforcing sheet 1 is brought into contact with one surface in the thickness direction of the metal panel 5.

Next, as shown in FIG. 2B, the metal panel 5 on which the reinforcing sheet 1 is arranged is heated. Thereby, the foamable resin layer 3 foams to become the foam layer 13, and as a result, the foamed reinforcing sheet 11 is obtained. When the expandable resin layer 3 has thermosetting property, the expandable resin layer 3 is cured to become the cured foam layer 13, and the foam reinforcing sheet 11 is fixed to the metal panel 5.

The heating temperature is, for example, 140° C. or higher, preferably 160° C. or higher, and for example, 220° C. or lower, preferably 200° C. or lower.

The heating time is, for example, 5 minutes or more, preferably 10 minutes or more, and for example, 60 minutes or less, preferably 30 minutes or less.

Since the foamable resin layer 3 is laminated on the metal layer 4, the foaming ratio of the foamable resin layer 3 is larger than that when glass cloth is laminated on the foamed resin layer 3. Specifically, it is, for example, 2.0 times or more, preferably 3.0 times or more, and for example, 10 times or less. The expansion ratio is calculated by the ratio of the thickness of the foam layer 13 (foamable resin layer after foaming) to the thickness of the foamable resin layer 3 before foaming (thickness after foaming/thickness before foaming).

Thereby, the reinforcing structure 6 including the metal panel 5 and the foamed reinforcing sheet 11 arranged on one side in the thickness direction is obtained.

The foam reinforcing sheet 11 includes a foam layer 13 and a metal layer 4 arranged on one side in the thickness direction thereof. The foam reinforcing sheet 11 has one large through hole 2 in the central region 9.

The foam layer 13 is a foam obtained by foaming the expandable resin layer 3. The foam layer 13 is formed in substantially the same shape as the metal layer 4 in a plan view. The foam layer 13 is a single layer.

The foam layer 13 has a thickness of, for example, 0.3 mm or more, preferably 1.5 mm or more, and for example, 15 mm or less, preferably 9 mm or less.

The ratio (C ₂ /C ₁ ) of the linear thermal expansion coefficient C ₂ of the metal panel 5 to the linear thermal expansion coefficient C ₁ of the metal layer 4 is, for example, 0.4 or more, preferably 0.6 or more, and more preferably Is 0.8 or more, and is, for example, 3 or less, preferably 2 or less, and more preferably 1.5 or less. Thereby, the distortion of the metal panel 5 can be suppressed.

The reinforcing sheet 1 includes a foamable resin layer 3 and a metal layer 4 arranged on one side in the thickness direction thereof. Therefore, when the foamable resin layer 3 foams, it is possible to suppress the gas from the foaming agent from passing through the metal layer 4. Therefore, the foamable resin layer 3 has excellent foamability, and a resin layer (specifically, the foam layer 13) having a desired thickness can be obtained. Therefore, the bending strength of the reinforcing sheet 1 is excellent.

Further, since the reinforcing sheet 1 has the large through holes 2, when the reinforcing sheet 1 is arranged on the metal panel 5 and the expandable resin layer 3 is foamed, the expandable resin layer 3 contracts in the surface direction or Since the stress caused by the expansion (in particular, the stress concentrated toward the central region of the metal layer 4 or the metal panel 5) can be relaxed, the strain of the metal panel 5 can be suppressed.

Further, the large through hole 2 is formed at least in the central region 9. Therefore, the stress concentrated on the center of the metal layer 4 can be reliably relaxed, and the distortion of the metal panel 5 can be suppressed uniformly and reliably.

The metal panel structure 6 is obtained by adhering the reinforcing sheet 1 to the metal panel 5, foaming and fixing the same. That is, the metal panel structure 6 includes the metal panel 5 and the foam reinforcing sheet 11 arranged on one side in the thickness direction thereof. The foam reinforcing sheet 11 includes a foam layer 13 arranged on one side in the thickness direction of the metal panel 5 and a metal layer 4 arranged on the thickness direction side of the metal panel 5, and the foam reinforcing sheet 11 has a large penetration. It has holes 2. Therefore, the metal panel structure 6 has suppressed distortion and improved strength.

3. Modifications Modifications of the reinforcing sheet 1 of the first embodiment will be described with reference to FIGS. 3 to 7. In the modification, the same members as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted. The embodiments and modified examples can be combined as appropriate.

(1) In the embodiment shown in FIG. 1A, the reinforcing sheet 1 has a large through-hole 2 having a substantially elliptical shape. However, as shown in FIG. 3, the reinforcing sheet 1 has a substantially circular shape (a substantially perfect circle). It is also possible to have a large through hole 2 of a shape). That is, the shape of the large through-hole 2 in FIG. 1A is a curve formed from a set of points where the sum of distances from two fixed points on the plane is substantially constant, and has a major axis and a minor axis. On the other hand, the shape of the large through hole 2 in FIG. 3 is a curve formed from a set of points whose distance from one fixed point on the plane is substantially constant.

The embodiment shown in FIG. 3 also has the same effects as those of FIG. 1A. Preferably, the embodiment shown in FIG. 1A may be mentioned from the viewpoint of suppressing the strain along the second direction of the reinforcing sheet 1.

(2) In the embodiment shown in FIG. 1A, the reinforcing sheet 1 has one large through hole 2, but, for example, as shown in FIGS. 4 to 6, a plurality of small through holes 8 (through holes). One example) may be included.

In the embodiment shown in FIG. 4, a plurality (five) of small through holes 8 are formed only in the central region 9 (inside the phantom line). The small through holes 8 have the same shape and are arranged at equal intervals along the circumferential direction. The small through hole 8 has a circular shape.

In the embodiment shown in FIG. 5, a plurality of (four) small through holes 8 elongated in one direction (first direction) are formed in the central region 9 and the outer peripheral region thereof. The small through holes 8 have the same shape and are arranged at equal intervals along the second direction.

In the embodiment shown in FIG. 6, a plurality (15) of small through holes 8 are formed in the central region and the outer peripheral region thereof. The small through holes 8 have the same shape and are arranged at equal intervals along the first direction and the second direction.

In addition, in the embodiment shown in FIGS. 4 to 6, the area of the through holes means the total area of the small through holes 8.

The number of the small through holes 8 is not limited and can be appropriately determined. The area of the small through hole 8 is not limited and can be appropriately determined. However, the area of the small through hole 8 is preferably substantially the same as the area of the large through hole 2.

The embodiment shown in FIGS. 4 to 6 also achieves the same effect as that of FIG. 1A. Preferably, from the viewpoint of manufacturability (workability), the embodiment shown in FIG. 1A can be mentioned.

(3) In the embodiment shown in FIG. 1A, the reinforcing sheet 1 has a substantially rectangular outer shape, but the outer shape is not particularly limited. For example, as shown in FIG. 7, the reinforcing sheet 1 has a substantially elliptical shape. Alternatively, although not shown, it may have a substantially circular shape. These embodiments also have the same effects as those of FIG. 1A.

Further, in the embodiment shown in FIG. 1A, the center of the large through hole 2 coincides with the center C of the reinforcing sheet 1 (the same circle), but for example, although not shown, the center of the large through hole 2 is , Does not have to coincide with the center C of the reinforcing sheet 1 (may be eccentric).

(4) Although not shown, the reinforcing sheet 1 may include a separator on the other side in the thickness direction of the foamable resin layer 3.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited to the examples and comparative examples. Further, specific numerical values such as a mixing ratio (content ratio), physical property values, and parameters used in the following description are described in the above “Mode for carrying out the invention”, and a corresponding mixing ratio ( Content ratio), physical property value, parameter, etc. are replaced by the upper limit value (value defined as "below" or "less than") or lower limit value (value defined as "greater than or equal to" or "exceeded") be able to.

Example 1
Aluminum foil having a substantially rectangular shape in plan view (first direction length: 50 mm, second direction length: 100 mm, thickness: 0.2 mm, UACJ, "3003", linear thermal expansion coefficient: 24 x ^10-6 ) Affix a foaming adhesive tape (foaming thermosetting elastic resin layer, single layer, length in first direction 50 mm, length in second direction 100 mm, thickness 1.0 mm), and elliptical shape in the central region A through hole having a short axis length of 20 mm and a long axis length of 40 mm was formed. This produced the reinforcing sheet of Example 1 (see FIG. 1A).

The foamable thermosetting elastic resin layer is made of the following materials.
70 parts by mass of bisphenol type epoxy resin ("Epicoat #872" manufactured by Japan Epoxy Resin Co., Ltd.)
-Bisphenol type epoxy resin 30 parts by mass (made by ADEKA, "EP-4080E")
40 parts by mass of polybutadiene rubber ("Tuffden 2003" manufactured by Asahi Kasei Chemicals Corporation)
10 parts by mass of acrylonitrile butadiene rubber ("Nipol 1052J" manufactured by Nippon Zeon Co., Ltd.)
2.5 parts by mass of foaming agent ("N#10000S" manufactured by Eiwa Chemical Industry Co., Ltd.)
・50 parts by weight of tackifier (Tosoh Corporation, petroleum resin, "Petrotac 90V")
50 parts by weight of filler (Maruo Calcium Co., heavy calcium carbonate)
-Curing agent 3 parts by mass (Nippon Carbide Mining Co., Ltd., dicyandiamide)
・Vulcanizing agent 12 parts by mass (Tsurumi Chemical Industry Co., Ltd., "Kinka fine powder sulfur")
・Vulcanization accelerator 6 parts by mass (Ono Shinko Kagaku Co., Ltd., "Nox Cellar DM")
Comparative Example 1
A reinforcing sheet of Comparative Example 1 was produced in the same manner as in Example 1 except that no through hole was formed.

Comparative example 2
A reinforcing sheet of Comparative Example 2 was manufactured in the same manner as Comparative Example 1 except that the aluminum foil was changed to glass cloth (thickness: 0.2 mm).

(Foamability test)
The reinforcing sheets of Examples and Comparative Examples were attached to the entire surface of an aluminum plate (first direction length 50 mm, second direction length 100 mm, thickness 1 mm) so that the foamable resin layer was in contact, and subsequently, The foamable resin layer was foamed by heating at 180° C. for 20 minutes. This produced the metal panel structure. The expansion ratio (thickness of the foam layer/thickness of the expandable resin layer) at this time was measured. The results are shown in Table 1.

(Bending strength test)
One side of the aluminum sheet (“A6061”, first direction length 25 mm, second direction length 150 mm, thickness 1.0 mm, linear thermal expansion coefficient 24×10 ⁻⁶ ) of the reinforcing sheet of the example or each comparative example was used. The whole surface was attached in an atmosphere of 20° C. and heated at 180° C. for 20 minutes. In this way, the foamable resin layer was foamed and cured to obtain a test piece (reinforcing structure).

Then, with the aluminum panel facing upward, each test piece was supported at intervals of 100 mm, and the test bar was vertically lowered from above at a compression speed of 5 mm/min at the center in the longitudinal direction, and the test piece was placed on the aluminum panel. After the contact, the bending strength (N) when the reinforcing sheet was displaced to 1 mm or 2 mm was measured. The results are shown in Table 1.

(Distortion test)
Aluminum sheet 5 (“A6061”, first direction length 200 mm, second direction length 300 mm, thickness) of reinforcing sheet 1 (first direction length 50 mm, second direction length 100 mm) of Example or each comparative example 1 mm) was attached to the central portion of the upper surface in an atmosphere of 20° C. (see FIG. 8A). Next, the measurement points 10 on the lower surface of the aluminum panel are determined at a pitch of 1 mm in the first direction 180 mm width and at a pitch of 5 mm in the second direction 200 mm width (see FIG. 8B), and the displacement of the surface unevenness is measured by a laser displacement meter. It was measured using.

Then, the foamable resin layer was foam-cured by heating at 180° C. for 20 minutes in a state where the reinforcing sheet-attached aluminum panel was vertically stood to obtain a reinforcing structure. With respect to the lower surface of the aluminum panel of the reinforcing structure, the displacement of the surface unevenness was measured again under the same conditions.

The difference between the displacement after heating and the displacement before heating was calculated, and the maximum value was taken as the amount of strain. The results are shown in Table 1.

From Table 1, comparing Example 1 and Comparative Example 1, it can be seen that Example 1 has a smaller strain amount. Further, comparing Comparative Example 1 and Comparative Example 2, it can be seen that the expansion ratio is increased by using the constraining layer as a metal layer. Furthermore, it can be seen that even in Example 1 having through holes in the reinforcing sheet, the expansion ratio is higher than in Comparative Example 2.

1 Reinforcement Sheet 2 Large Through Hole 3 Foaming Resin Layer 4 Metal Layer 5 Metal Panel 6 Metal Panel Structure 8 Small Through Hole 9 Center Region 13 Foam Layer

Claims (10)

A reinforcing sheet attached to the panel,
A foaming resin layer containing a foaming agent and comprising a single layer,
A metal layer disposed on one side in the thickness direction of the foamable resin layer,
A reinforcing sheet having a through hole penetrating the reinforcing sheet in a thickness direction. The reinforcing sheet according to claim 1, wherein the linear thermal expansion coefficient of the metal layer is 5×10 ⁻⁶ or more and 30×10 ⁻⁶ or less. The reinforcing sheet according to claim 1 or 2, wherein the metal layer has a thickness of 0.01 mm or more and 3 mm or less. The reinforcing sheet according to any one of claims 1 to 3, wherein a ratio of the planar view area of the through hole to the planar view area of the reinforcing sheet is 10% or more and 80% or less. The reinforcing sheet according to claim 1, wherein the through hole has a substantially elliptical shape or a substantially circular shape. The reinforcing sheet according to claim 1, wherein the through hole is formed at least in a central region. The reinforcing sheet according to any one of claims 1 to 7, wherein the panel is a metal panel. Panel,
A reinforcing structure comprising a reinforcing sheet arranged on one side in the thickness direction of the panel,
The reinforcing sheet is
A foam layer composed of a single layer, which is arranged on one side in the thickness direction of the panel,
A metal layer disposed on one side in the thickness direction of the foam layer,
The reinforcing sheet has a through-hole penetrating in the thickness direction. The reinforcing structure according to claim 8, wherein the panel is a metal panel. The ratio (C ₂ /C ₁ ) of the linear thermal expansion coefficient C ₂ of the panel to the linear thermal expansion coefficient C ₁ of the metal layer is 0.4 or more and 3 or less. Alternatively, the reinforcing structure according to item 9.

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