JPH06226896A - Vibration-damping and vibration-damping composite structure - Google Patents

Abstract

PURPOSE:To provide a structure for a vehicle, etc., which is brought into close contact with a vibration board of the vehicle, etc., and in which noise reduction and fastness of the vehicle, etc., are improved. CONSTITUTION:A three-layer structure has a spacer sheet layer made of semi- gelatinized foamable heat-curable resin, a vibration-damping sheet and a metal plate restricting material, wherein the vibration-damping sheet contains polyacrylic acid ester in which glass transition temperature (Tg) is regulated to -20 deg.C or lower as a main ingredient, the spacer layer is foamed in a heating step such as a coating and drying step, etc., the structure is integrated to be brought into close contact with a vibration board of the vehicle, etc., to impart a light weight, vibration-damping, rigidity and excellent resistance (reinforcing properties) to deflection thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a door panel of a vehicle,
The present invention relates to a vibration damping and vibration damping composite structure which is integrated by fusion molding on a wide area substrate such as a fender panel, a ceiling panel or a trunk lid which is easy to vibrate and has low robustness.

[0002]

2. Description of the Related Art Vehicle door panels, fender panels,
On a vibration board surface such as a ceiling panel or a trunk lid, a heat-sealable damping material containing asphalt as a main component or an adhesive damping material containing butyl rubber as a main component may be fused or adhered and used. Many. In recent years,
On the surface of asphalt damping material, butyl rubber damping material,
As a restraint material, a metal sheet such as a steel plate or an aluminum plate is provided, or a thermosetting resin such as an epoxy resin, a diallyl phthalate resin, an acrylic resin, or a polybutadiene resin is laminated to provide a restraint type vibration damping structure with a damping property and rigidity. Attempts have also been made to improve the vibration damping performance, particularly by a method of foaming a vibration damping material containing asphalt as a main component. In addition to measures against vibration and noise due to improved vibration damping and rigidity, recent vehicles have been made thinner in order to reduce their weight. Therefore, in order to suppress the occurrence of bending when a force that presses the panel is applied, a bending resistance imparting material called a reinforcing material is often attached. This reinforcing material is generally made by laminating reinforcing fibers such as glass cloth on the surface of epoxy resin or the like.

[0003]

However, these damping structures have the following problems. That is, in the double-layer type damping structure for damping the vibration substrate only with the heat-fusible damping sheet having asphalt as a main component, it is necessary to increase the thickness in order to improve the damping performance, This will increase vehicle weight. Further, a technique of making the asphalt damping material foamable to suppress the weight increase has recently been used, but the weight reduction effect is not so large because the foaming ratio is not high in a practical range. Furthermore, since the asphalt damping material does not have self-adhesiveness in the normal construction temperature range, it is not inconvenient for application to the horizontal surface of the vehicle structure, but for application to inclined surfaces or vertical surfaces, It is necessary to use a product coated with an adhesive or tacky agent. Further, even if an adhesive is applied, since the asphalt-based damping material has a high weight (area density), it often drops down during baking due to its own weight, and it can be used only in a limited manner. There is also a method of using a sandwich type vibration damping structure in which a metal plate such as a steel plate, an aluminum plate or a thermosetting resin is laminated as a restraining agent on the upper surface of an asphalt-based heat-fusible damping material. However, this method is effective as a measure to improve the loss factor and rigidity, but from the viewpoint of recent noise reduction in the vehicle, it is possible to improve the loss factor in a practical range that does not significantly increase the weight. Has a limit. Also in this case, similar to the double layer structure, there is a problem in application to an inclined surface or a vertical surface.

In order to improve these problems and apply them to inclined surfaces or vertical surfaces, recently, a butyl rubber self-adhesive damping material using an aluminum plate as a restraining material has come to be used for vehicles. ing. Such a vibration control structure is often applied to doors, fenders, trunk lids, inclined surfaces such as ceilings, vertical surfaces, etc., due to its ease of attachment due to its self-adhesiveness. In addition, since these damping materials also have a restraint type damping structure, they also have a high loss coefficient. However, recently, it has become necessary to improve fuel efficiency and further reduce noise.
At present, there is a demand for a vibration-damping material and a vibration-damping structure that are light in weight and have a high loss coefficient. In addition, in these conventional damping structures, although the damping performance and rigidity (which are against vibration and not bending resistance) can be improved, the bending that occurs when a force is applied to the panel Resistance to the panel, that is, the panel reinforcing property, can hardly be expected, and the panel reinforcing material and the damping material are currently attached separately. Therefore, there is a two-step process of attaching both the damping material and the reinforcing material, which complicates the process and increases the cost associated therewith, and the development of a material having these two functions is strongly desired. It was

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and provides a structure to be laminated on a vibration substrate of a vehicle or the like, the structure being a foamable thermosetting resin. A spacer layer (I) composed of a sheet, a damping material sheet (II) laminated on the spacer, and a restraining material sheet (III) laminated on the damping material sheet, wherein the spacer sheet layer (I) Is a sheet that is semi-gelled by heating at a temperature below the decomposition gas generation temperature, and the vibration-damping material sheet comprises a polyacrylic ester whose glass transition temperature (Tg) is adjusted to -20 ° C or lower. A vibration-damping structure characterized by being a sheet containing the main component and the materials (I), (II), and (III) described above are heated on a vibration substrate to foam the spacer layer (I) and adhere them integrally. Vibration-damping composite structure formed by stacking layers In which more it is provided. Further, the present invention provides a high vibration damping property in a range where the weight increase of the vehicle is very small by fusion-bonding the structure with a vibration substrate such as a vehicle door, a fender, a trunk lid, and a ceiling, and It is intended to provide a structure suitable for a vehicle or the like that can improve rigidity and reinforcement. Furthermore, as this kind of vehicle structure,
By heat treatment in a drying step such as painting, it is necessary to complete the reaction, foaming, fusion bonding, etc. of each layer, and a material that is less likely to deteriorate in physical properties at relatively high temperatures is required, but The composite structure according to the invention meets exactly these requirements. Each constituent layer relating to the present invention will be described below.

The spacer layer (I) used in the present invention is a foamable thermosetting resin sheet, and imparts a function as a spacer in the structure of the present invention. The preferable characteristics of the spacer in the vibration control structure for vehicles are light weight and high elastic modulus, and they are adhered and fixed to the vibration substrate in the heating process such as the drying process of the coating in the vehicle manufacturing process, and moreover, in this process, It is that there is a foaming action of the magnification.
The composition of the spacer having such characteristics is not particularly limited, but for example, a liquid epoxy resin disclosed in Japanese Patent Application Laid-Open No. 4-264142 already proposed by the applicant of the present invention is used as a methacrylic resin, polybutene, and foam. Agent,
A composition comprising a curing agent for epoxy resin, a surfactant and the like is suitable. In the damping structure according to the present invention,
This foamable thermosetting resin sheet composition is used as a semi-gelled sheet. That is, the prepared composition is molded into a semi-gelled sheet at a temperature lower than the decomposition temperature of the foaming agent, usually at a relatively low temperature of about 100 to 150 ° C. Furthermore, in the present vibration-damping composite structure, after the spacer layer (I), the vibration-damping material sheet (II) and the restraining material sheet (III) are laminated on the vibration substrate, in the heating step, for example, the coating drying step. The spacer layer is foamed at 120 to 200 ° C. and cured by cross-linking of an epoxy resin, and at the same time, the vibrating substrate, the spacer layer, the damping material sheet and the constraining material sheet are integrally laminated. The expansion ratio of the foamable thermosetting resin sheet is 2
˜30 times, preferably 3 to 10 times. Expansion ratio is 2
The following can of course function as a spacer, but lack other properties such as lightness and heat insulation,
If the expansion ratio is 30 times or more, which is not the object of the present invention, the strength of the foam cells is insufficient, and the compression resistance strength is insufficient depending on the application site of the vehicle, and there is a possibility that it cannot be put to practical use. The thickness of the spacer layer after foaming is 1 to 50 mm, preferably 2 to 30 mm. When it is 1 mm or less, it cannot fulfill an effective function as a spacer layer, and when it is 50 mm or more, it becomes unpractical due to the narrow interior space in the vehicle application which is the object of the present invention. When it is attached to a vertical surface, a deviation occurs in the heating process or a uniform foaming property cannot be obtained.

The vibration-damping material sheet (II) provided for the structure of the present invention has a vibration-damping function in this structure and also functions as a binder for the spacer layer (I) and the restraining material sheet (III). The polyacrylic acid ester whose glass transition temperature (Tg) is adjusted to −20 ° C. or lower is a main component. The polyacrylic acid ester used here is not particularly limited except for its glass transition temperature, and may be a simple substance or a copolymer or mixture of two or more polyacrylic acid esters. Further, it means that the main component is a polyacrylic acid ester, which means that the polymer has sufficient tack force to serve as a binder between the restraining material and the foam spacer, improvement in shear adhesive strength, and other polymers for improving heat resistance. When copolymerized or blended with the above, it means that the component of the polyacrylic ester which is the polymer of the main component is contained in a predominant amount over the other components. The glass transition temperature of this polyacrylic ester is -20 ° C.
The following needs to be adjusted: When the glass transition temperature is -20 ° C or higher, the function as a binder between the constraining material and the foam spacer, such as the tack force and shear adhesive strength of the polyacrylic acid ester, becomes insufficient, and separate adhesion treatment is required. Because it will be. The lower limit of the glass transition temperature is not particularly limited, but is about −100 ° C. in view of the practical structure of polyacrylic acid ester.

Here, the glass transition temperature of the polyacrylic acid ester being adjusted to -20 ° C or lower means that the glass transition temperature of the polyacrylic acid ester is -20 ° C or lower or -20 ° C or higher. Polyacrylic acid ester with tricresyl phosphate (TCP), acetyltributoxy sylate (ATBC), dioctyl phthalate (DOP), dioctyl adipate (DO)
A), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP) and other polyacrylic acid ester compatible plasticizers are added to reduce the glass transition temperature.
You may make it 20 degrees C or less. Examples of these polyacrylates include polyacrylates such as methyl polyacrylate, ethyl polyacrylate, 2-ethylhexyl polyacrylate, n-octyl polyacrylate, n-butyl polymethacrylate, and n-polymethacrylate. Examples thereof include polymethacrylates such as tetradecyl. The thickness of the present damping material sheet is not particularly limited, but considering that it is formed as a vehicle structure and has a function as a reinforcing material, it is 1.0 mm or less, preferably 0.5 to It is 0.05 mm. Since the present vibration-damping material sheet has a relatively low elastic modulus, when the thickness is 1.0 mm or more, the resistance to bending, that is, the reinforcing property cannot be sufficiently exhibited, and it also goes against weight reduction. In addition, an effective loss factor cannot be obtained for the thickness, which is economically disadvantageous, and when attached to a panel with a vertical surface such as a door, the weight of the panel tends to cause slippage in the heating process. . However, in order to effectively develop the loss coefficient, it is 0.05 mm, preferably 0.
A thickness of 1 mm is needed. In the composition of the vibration-damping material sheet of the present invention, in addition to the above-mentioned composition, as long as it does not impair the function as a vibration-damping material and there is no hindrance during the formation of a vehicle panel or during use, , Softeners for the purpose of improving adhesive strength, durability, etc., inorganic fillers such as calcium carbonate, talc, clay including tackifiers, halogen compounds, antimony oxide, flame retardants such as zinc borate hydrate, heat Additives such as stabilizers, UV inhibitors, antioxidants and crosslinking agents can be used.

The restraining material sheet (III) provided for the structure of the present invention restrains the deformation of the damping material sheet (II) due to the vibration, and the shearing deformation of the damping material sheet is applied to the structural body. It provides a large loss coefficient and resistance to flexural deformation, that is, reinforcement.
It is preferable that the material used for the restraint material sheet has a high elastic modulus and does not impair the function as a vehicle material. A metal sheet is preferable as a material satisfying such conditions, and a steel plate and an aluminum plate are particularly preferable from the viewpoint of easy availability. The thickness of such a restraint material sheet may vary depending on the difference in elastic modulus depending on the type of metal and the desired loss coefficient and reinforcing property, but in the case of a steel plate or an aluminum plate, it is 0.0
A range of 1 to 1 mm, preferably 0.1 to 0.5 mm is sufficient. When the thickness is 0.01 mm or less, the function as a restraining material sheet is low and a problem in strength occurs. Also,
When the thickness is 1 mm or more, the specific gravity of the metal sheet is high, so that the weight becomes large, which is contrary to the weight reduction which is one of the gist of the present invention.

The production of the structure according to the present invention as described above is carried out by the spacer sheet layer (I), the damping material sheet (II),
The restraining material sheet (III) may be laminated, and the spacer sheet may be heated and bonded and laminated at a temperature at which the spacer sheet is semi-gelled. The spacer sheet is heated in advance to be semi-gelled, and the damping material sheet and the restraining material sheet are required. Correspondingly, a known adhesive may be used for adhesive lamination. In the composite structure of the present invention, each of the above materials is individually placed on the vibration substrate, the reinforcing substrate, or the like of the vehicle and heated to utilize the adhesiveness of the foam spacer layer (I) and the vibration damping sheet (II). It may be laminated, and (I), (II) and (III) are previously attached to each other by utilizing the adhesiveness of the foam spacer layer (I) and the damping material sheet (II) to form the present structure. It may be attached to a vibration board or a reinforcing board of a vehicle.

[0011]

The damping structure according to the present invention is mounted on a vibrating substrate such as a vehicle door panel, fender panel, trunk lid or ceiling panel, and is firmly fixed to each layer and the vibrating substrate by heating and the spacer is foamed. Thus, the composite structure is lightweight and has excellent vibration damping properties, rigidity and reinforcement properties, and is suitably used as a material for reducing noise and robustness of vehicles and the like.

[0012]

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples. The materials used and the test method are as follows. (1) Test material Foamable thermosetting resin sheet (spacer layer): A foamable thermosetting resin composition having a compounding ratio shown in Table 1 was mixed by a Hobart mixer for 20 minutes, and then produced to a predetermined thickness on a release paper. Was applied. This was heated at 120 ° C. for 100 seconds to prepare a semi-gelated sheet. Damping material sheet: A damping material composition having a compounding ratio shown in Table 2 was dissolved in a solvent (toluene) to prepare a 50% solution. This was coated on a release paper in a predetermined thickness and dried to remove the solvent. As a comparative example, an asphalt damping material was used. Restraint material sheet: Throughout the examples and comparative examples, the plate thickness is 0.
A 2 mm aluminum plate was used.

[0013]

[Table 1]

[0014]

[Table 2]

(2) Method for manufacturing test body The unfoamed semi-gelled sheet, damping material sheet and restraint material sheet formed in (1) were placed on a steel plate having a thickness of 1.0 mm, and Table 3 After the test structure having the structure shown in (1) was produced, this was heated in an atmosphere of 165 ° C. for 20 minutes to bond and fix each sheet, and the foaming thermosetting resin was also foamed. The size of the test body at this time is 30 x 300 m
It was m.

[0016]

[Table 3]

(3) Test method Loss coefficient and rigidity ratio of structure Using the above test body, loss coefficient and rigidity ratio were set to 10, 20, 4
It was measured in an atmosphere of 0 ° C. The loss coefficient was calculated from the half width value of the mechanical impedance at the resonance frequency, and was calculated as the loss coefficient of 200 Hz by the interpolation method. The measurement frequency range is 1 to 1000 Hz. The rigidity was calculated by the following formula 1 in the form of the ratio to the rigidity of the vibration substrate, that is, the rigidity ratio.

[0018]

[Equation 1] Stiffness ratio = (f / f ₀ ) ² · {(m ₁ + m ₂ ) / m ₁ } where, f ₀ : Resonant frequency (Hz) of a single steel plate f: When a composite structure is used Resonance frequency (Hz) m ₁ : Area density of steel sheet alone (kg / m ² ) m ₂ : Area density of composite structure (kg / m ² ) f: Resonance of composite structure Frequency (Hz).

A structure was produced in the same manner as the reinforcing property (2) of the structure. However, the size of the test body for evaluation of the reinforcing property is 80 mm × 80 mm, which is 0.8 mm.
A 50 × 150 mm test structure was formed in the center on a thick steel plate. The baking and foaming conditions are the same as in (2). The reinforcing property was evaluated by performing the same test as the ordinary bending test method on the above-mentioned structure and by the load showing the maximum at the time of displacement of 2 mm. The crosshead speed of the tester is 5 mm /
The distance between the minutes and the span is 100 mm. Glass transition temperature The glass transition temperature of the polyacrylic acid ester was determined from the endothermic curve using a differential thermal analyzer (model DSC220) manufactured by Seiko Denshi Kogyo. The heating rate is 5 ° C./min.
Table 4 shows the evaluation results of the examples and Table 5 shows the evaluation results of the comparative examples according to the above tests.

[0020]

[Table 4]

[0021]

[Table 5]

As shown in Tables 4 and 5, the structures according to the present invention are excellent in loss factor, rigidity, flexibility and adhesive strength, while in Comparative Examples 1 to 6, the loss factor is high. It is considerably bad and the vibration damping property is also very bad. The load at the displacement of 2 mm is not much different from that of the example. However, regarding the load at the maximum deflection, in each of Comparative examples 1, 2, 4, 5, and 6, whether the peeling occurs between the damping material sheet and the restraining material sheet, The breakout sheet was destroyed.

Claims (2)

[Claims] 1. A structure laminated on a vibration substrate, comprising:
The structure comprises a spacer layer (I) made of a foamable thermosetting resin sheet, a damping material sheet (II) laminated on the spacer, and a restraining material sheet (III) laminated on the damping material sheet. The spacer sheet (I) is a sheet that is semi-gelled by heating at a temperature not higher than a decomposition gas generation temperature, and the damping material sheet has a glass transition temperature (Tg) of -20 ° C or lower. A vibration-damping structure characterized in that it is a sheet containing a polyacrylic acid ester as a main component, which has been adjusted to. 2. A vibrating substrate, a spacer layer (I) comprising a semi-gelled foamable thermosetting resin sheet which is heated at a temperature below a decomposition gas generation temperature, and a glass transition temperature (Tg) on the spacer layer is −. A damping material sheet (II) containing polyacrylate ester adjusted to 20 ° C. or lower as a main component, a restraining material sheet (III) laminated on the damping material sheet, and the spacer layer is foamed by heating. A vibration-damping composite structure in which the vibrating substrate, a spacer layer, a vibration-damping material sheet, and a restraining material sheet are laminated and adhered.