JPH0755550B2 - Vehicle laminated structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention is for a vehicle that is integrated by heat fusion molding on a substrate such as a floor panel, dash panel, door panel, or ceiling panel of a vehicle that is prone to vibration. The present invention relates to a vibration control / high rigidity structure.

[Prior Art] A heat-sealable damping material containing asphalt as a main component is often fused and used on the surface of a vibrating substrate such as a vehicle floor panel, a dash panel, a door panel, and a wheelhouse.

In recent years, a metal sheet such as a steel plate or an aluminum plate is provided as a restraint material on the upper surface of an asphalt damping material, or a thermosetting resin such as an epoxy resin, a diallyl phthalate resin, or an acrylic resin is laminated to restrain the damping material. The structure is also being improved in vibration damping performance and rigidity.

Furthermore, recently, attempts have been made to improve the vibration damping performance by a method of foaming a vibration damping material containing asphalt as a main component.

[Problems to be Solved by the Invention] However, these damping structures have the following problems. In other words, in a double-layer type vibration damping structure in which the vibration base material is damped only by the heat fusion vibration damping sheet whose main component is asphalt, it is necessary to increase the thickness in order to improve its vibration damping performance. However, this will increase the vehicle weight and hardly improve the rigidity of the structure.

Further, a technique for making the asphalt damping material foamable and suppressing the weight increase has recently been started to be used, but the improvement factor of the loss coefficient in a practical range is not great.

Further, in the case of a sandwich type vibration damping structure in which a steel plate, an aluminum plate or the like is laminated on the upper surface of the asphalt-based heat-sealing vibration damping sheet, the vibration damping performance as a structure is improved, but a metal having high rigidity as a restraint layer is used. In order to bring the plate into close contact with the heat-fusible damping sheet, it is necessary to fix it mechanically to a highly rigid vibrating base material such as a steel plate, or fix it with screws such as bolts. is there. However,
Generally, vehicle floor plates are press-formed into an uneven shape for the purpose of imparting rigidity, so it is necessary to form the restraint metal plate into a shape complementary to this, which requires an extra step and is installed. At this time, there is a problem in that it is not easy to correctly position at a predetermined position.

In addition, a method of placing an uncured thermosetting resin on a damping material and curing it in the drying process of coating to use it as a restraining material, or a thermoplastic resin using a tackifier resin as a base material There is also a method in which it is placed on a material and heat-bonded in a coating and drying step to be used as a restraining material.

The method of using these hard resin materials as a restraint material is certainly effective in improving the loss coefficient and rigidity, but from the viewpoint of the recent reduction of vehicle interior noise, it is accompanied by a significant increase in weight. The current situation is that there is a shortage in the range in which the loss factor and rigidity are improved when the resin restraint material is used in a practical range that is not present.

[Means for Solving the Problems] The present invention has improved such problems, and a lower layer sheet (1) made of a foamable thermosetting resin sheet laminated on a vibration substrate in a vehicle, and the lower layer. Intermediate sheet (2) consisting of a vibration damping sheet laminated on the sheet (1)
And a constraining material sheet (3) laminated on the intermediate sheet, the contact surfaces of these sheets and the vibration substrate are integrally fused by heating, and the lower layer sheet (1) foams. The present invention relates to a characteristic laminated structure for a vehicle.

Further, the present invention provides a vehicle panel capable of dramatically improving rigidity as well as imparting an excellent loss coefficient in a range where a weight increase is small by fusing and integrating the structure with a vehicle vibration substrate. It is provided.

Further, as a vehicle panel structure of this type, it is necessary to adhere to a vibrating substrate having irregularities by heat treatment in a drying process such as painting, and complete reaction, foaming, fusion bonding, etc. of each layer. Although a material having a small decrease in physical properties even at a relatively high temperature is required as a preferable property, the structure according to the present invention exactly meets these requirements.

When the vehicle laminated structure according to the present invention is schematically illustrated,
FIG. 1 is a cross-sectional view before heat fusion foaming, in which a lower layer sheet (1) is laminated on a vibration substrate (4), an intermediate sheet (2) is laminated on the lower layer sheet (1), and further an intermediate sheet (2). ) A constraining material sheet (3) is laminated thereon. The second is a state in which the vibrating substrate and the contact surfaces of the respective sheets are integrally fused by heating and the lower layer sheet is foamed. Further, FIG. 3 also shows a state in which the intermediate sheet (2) using the foamable vibration damping sheet is also foamed by heating.

Hereinafter, each constituent layer relating to the present invention will be described.

The lower layer sheet (1) used in the present invention imparts a function as a spacer, and preferable properties as a spacer for vehicle use are light weight, high rigidity, and little deterioration of physical properties due to temperature change, and in a coating drying step. The reason is that it is closely adhered and fixed to the uneven vibration substrate, and has a high-magnification foaming action in this process. From this point of view, the foamable thermosetting resin sheet is suitable for the purpose. Among them, it contains vinyl chloride resin, epoxy resin, epoxy resin curing agent, plasticizer and foaming agent, and the vinyl chloride resin is semi-gelled. Those in a state (hereinafter abbreviated as an epoxy foam composition) are excellent in shape retention as a sheet state, storability, adhesion to a vertical vibration substrate, and the like.

Here, the vinyl chloride resin is in a semi-gelled state,
The epoxy resin does not undergo a curing reaction, and only the vinyl chloride resin refers to a state in which the plasticizer has penetrated into the interior and gelation has started.

The epoxy resin foaming composition to be used for this lower layer sheet is a composition comprising a bubble adjusting agent, a filler, a viscosity adjusting agent, a heat stabilizer, a pigment and the like as other optional components, and at a temperature not higher than the decomposition temperature of the foaming agent in advance. It is formed into a sheet and is used in the next heating step, such as the coating drying step.
It is capable of foaming at a temperature of up to 200 ° C and being cured by crosslinking of an epoxy resin.

As the vinyl chloride resin, not only vinyl chloride homopolymer but also vinyl chloride, vinyl acetate, acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester,
Known copolymers with maleic acid, fumaric acid, maleic acid ester, fumaric acid ester, itaconic acid, vinylidene chloride, vinyl ether and the like can be used alone or in combination. As the vinyl chloride polymer (including a copolymer), those produced by any known method such as emulsion polymerization and suspension polymerization can be used, but particularly those produced as emulsion polymerization or fine suspension polymerization for pastes. It is preferable to use the above alone or in combination with those obtained by suspension polymerization, from the viewpoint of easy sheet formation and a cell structure at the time of foaming.

Examples of the plasticizer include phthalates such as dioctyl phthalate and dibutyl phthalate, phosphates such as tricresyl phosphate, fatty acid esters such as dioctyl adipate and dioctyl sebacate, for example, a condensate of adipic acid and ethylene glycol. Known vinyl chloride plasticizers such as various polyesters, trimellitic acid esters such as trioctyl trimellitate, chlorinated paraffins, alkylbenzenes, and high molecular weight aromatics can be used alone or in combination. The amount of plasticizer blended is
Although not particularly limited, it is preferably mixed in an amount of more than 10 parts by weight and 150 parts by weight or less with respect to 100 parts by weight of vinyl chloride. If the compounding amount is 10 parts by weight or less, the expansion ratio does not improve, and if it exceeds 150 parts by weight, the hardness does not increase and the reinforcing effect becomes small.

As the foaming agent, a high temperature decomposition type organic or inorganic foaming agent, a high temperature expansion type microcapsule and the like are used. Organic blowing agents include azodicarbonamide, paratoluenesulfonyl hydrazide, dinitrosopentamethylenetetramine,
4,4′-oxybisbenzenesulfonyl hydrazide and the like are used. The decomposition temperature of the organic foaming agent can be arbitrarily adjusted with urea, a zinc compound, a lead compound or the like. The inorganic foaming agent is
Examples include sodium bicarbonate and sodium borohydride. As the high temperature expansion type microcapsules, those obtained by encapsulating a low boiling point hydrocarbon with vinylidene can be used. In the present invention, any foaming agent can be applied, but an organic foaming agent having a decomposition temperature of 100 ° C. or higher is particularly preferable in view of easiness of forming into a sheet, appearance of the foam, uniform foaming and compactness. If the decomposition temperature is 100 ° C or lower, foaming may start when it is formed into a sheet, or the resin may not be sufficiently melted during foaming in a heating furnace and gas may escape and the expansion ratio may not increase.
It is difficult to obtain a uniform foam. Further, an inorganic foaming agent or microcapsules can be used, but there is a problem in terms of expansion ratio and economical efficiency. The blending amount of foaming agent is vinyl chloride resin
It is preferably 0.5 to 15 parts by weight with respect to 100 parts by weight.
If the compounding amount is less than 0.5 part by weight, foaming is insufficient, and if it exceeds 15 parts by weight, the foaming degree does not change, and it is economically wasteful to add excessively.

Examples of the epoxy resin applicable to the present invention include usual glycidyl ether type, glycidyl ester type, glycidyl amine type, linear aliphatic epoxide type, and aliphatic epoxide type epoxy resins, and desired foams. They can be used alone or in combination depending on the physical properties of. The compounding amount of the epoxy resin is in the range of 20 to 500 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. If the blending amount is less than 20 parts by weight, it is difficult to obtain a hard foam, and if it exceeds 500 parts by weight, the heat generated during curing is large, so that the decomposition of vinyl chloride occurs or the expansion due to the decomposition gas of the foaming agent is suppressed. This causes problems such as difficulty in obtaining a high-magnification foam.

As the heat-activatable curing agent for the epoxy resin, a usual curing agent exhibiting a curing action by heating can be used. A preferred curing agent is a curing agent having an exothermic peak temperature in the range of 100 ° C to 200 ° C in combination with an epoxy resin.
Examples of the curing agent include dicyandiamide, 4,4′-diaminodiphenylsulfone, imidazole derivative such as 2-n-heptadecylimidazole, isophthalic acid dihydrazide, N, N-dialkylurea derivative, N, N-dialkylthiourea derivative. Acid anhydrides such as tetrahydrophthalic anhydride, isophoronediamine, metaphenylenediamine, N-aminoethylpiperazine, boron trifluoride complex compounds, trisdimethylaminomethylphenol and the like. The curing agents can be used alone or in combination as desired. Epoxy resin 10
It is preferably 1 to 20 parts by weight with respect to 0 parts by weight. If the blending amount is less than 1 part by weight, the rigidity of the foam is insufficient due to insufficient curing. On the other hand, if the blending amount is more than 20 parts by weight, the rigidity of the foam does not change, and excessive addition is economically wasteful.

The curing temperature referred to here is the temperature of the medium at which the heat generated by curing reaches a peak when a mixture of an epoxy resin and a curing agent at room temperature is heated by an oil bath, a heater, or the like.

The preferred combination and amount of the epoxy resin and the curing agent depending on the heating conditions can be easily determined by conducting a test in advance.

In the present invention, in addition to these essential ingredients, for example, fillers such as calcium carbonate, talc and clay, heat stabilizers,
A bubble regulator and a coloring agent can be added. The compounding amount of each of the above-mentioned compounding agents is in the range of 0 to 200 parts by weight for the filler, 0 to 10 parts by weight for the heat stabilizer, and 0 to 10 parts by weight for the cell regulator with respect to 100 parts by weight of the vinyl chloride resin. . When blending each compounding agent, if the filler is more than 200 parts by weight, the fineness of foaming is lost, the expansion ratio does not increase, and even if the heat stabilizer and the cell regulator are more than 10 parts by weight. No effect.

The expandable resin composition applied to the present invention includes a vinyl chloride resin, a plasticizer, a foaming agent, an epoxy resin, and a curing agent for an epoxy resin, and if necessary, a bubble regulator, a filler, a heat stabilizer, and a coloring agent. An agent and the like are added, and the mixture is homogenized and adjusted by a generally known kneader.

The expansion ratio of the lower layer sheet is 2 to 30 times, preferably 5 times.
It is about 10 times. Of course, a foaming ratio of 2 times or less can function as a spacer, but it is not the gist of the present invention from the viewpoint of light weight, heat insulating property, etc. When a foaming ratio of 30 times or more is used, the strength of the foam cell is increased. There is a shortage, and there may be a problem with durability depending on the part where the vehicle is used.

The thickness of the spacer sheet after foaming is 1 to 50.
mm, preferably 3 to 30 mm. If it is 1 mm or less, it cannot function effectively as a spacer, and if it is 50 mm or more, it is not practical in the vehicle application which is the object of the present invention and the space inside the vehicle becomes narrow and it is a heating step such as a coating drying step. In that case, a uniform foaming property cannot be obtained.

The intermediate sheet (2) used in the present invention has a function as a vibration damping sheet, and is not particularly limited in type such as rubber type, resin type, and asphalt type, but an upper layer restraint sheet. (3), adhesion to the lower layer sheet (1) (heat-sealing property), followability to the uneven vibration substrate by heating, and the like may be required as long as they satisfy the required performances for vehicle applications.
From the viewpoints of satisfying such required performance, damping performance, cost, etc., the asphalt damping material and the foamable asphalt damping material are excellent and suitable for this purpose.

The thickness of the intermediate sheet is preferably 10 mm or less. If the thickness is 10 mm or more, the weight becomes extremely large and is not the gist of the present invention. Moreover, the lower limit of the thickness is not particularly set. This is because the structure of the present invention has a constrained type vibration damping structure, so that even if the intermediate sheet is thin, its function can be sufficiently exhibited.

The upper layer sheet (3) applied to the present invention is a restraint material for restraining the deformation of the vibration damping sheet, which is the intermediate sheet, due to the vibration, and imparting a large loss coefficient to the structure by applying shear deformation to the intermediate sheet. is there.

The material used for such a restraint material sheet satisfies the requirements of adhesion (heat fusion) with the intermediate sheet as well as the intermediate sheet and the lower layer sheet, and followability to the uneven vibration substrate by heating, and has a high elastic modulus as much as possible. Things are desirable.

As a desirable material satisfying such conditions, a tackifier such as a rosin resin, a terpene resin, an aliphatic petroleum resin, an aromatic petroleum resin, an alkylphenol-acetylene resin, a xylene resin, and a coumarone-indene resin is used. The contained thermoplastic resin sheet and thermosetting plastic sheet are suitable.

As a thermoplastic resin sheet containing a tackifier resin, there is JP-A-3-39056, and as a thermosetting plastic sheet, a rubber such as butadiene rubber or styrene-butadiene rubber is used as a base polymer. There is.

In particular, a thermoplastic resin sheet containing a tackifier resin is in a vehicle use state depending on the kind and content of the tackifier resin.
Holds a relatively high elastic modulus in the temperature range of ~ 60 ° C,
In particular, the structure according to the present invention is particularly advantageous because it becomes a low-viscosity melt in the temperature range of about 120 to 160 ° C., which is the temperature of the vehicle coating process, and it is easy to design the material so that it can follow a complicated uneven shape. It is suitable for use as a restraint sheet for
Since it contains no reactant, it is easy to handle from the viewpoint of storage stability.

The thickness of the binding material sheet is not particularly limited, but as a sheet formed on a vehicle floor panel or the like, from the same viewpoint as the lower layer and the intermediate sheet, it is usually
A range of 0.5 to 3 mm is sufficient.

In order to manufacture the structure related to the present invention, each of the lower layer sheet, the intermediate sheet, and the restraining material sheet is individually placed on the vibration substrate of the vehicle, and the vibration substrate, the lower layer sheet, and the intermediate layer are heated by heating in the coating and drying process. The sheet and the restraint material sheet may be fused and foamed with each other to simultaneously follow the unevenness of the vibrating substrate, or the three sheets of the lower layer sheet, the intermediate sheet and the restraint material sheet may be laminated in advance and dried. Fusion and foaming to the vibration substrate may be achieved in the process. Further, of course, the upper layer sheet and the intermediate sheet, or the lower layer sheet and the intermediate sheet may be combined.

[Effects of the Invention] As described above, the laminated structure for a vehicle according to the present invention is placed on a vibration substrate such as a floor panel or a dash panel of a vehicle, and a lower layer sheet or an intermediate sheet as necessary is heated. In addition to foaming, the layers and the vibration substrate can be firmly fixed to each other and the uneven shape of the vibration substrate can be followed.

The structure obtained in this way is a constrained type vibration damping structure in which a spacer having a small temperature change is provided in the lower layer, so that it not only exhibits an excellent vibration damping function over a wide temperature range, but also has a high The structure also has rigidity and is not only suitable as a material for reducing vehicle interior noise, but also provides a solid feeling of the vehicle panel and is a structure with excellent heat insulation.

[Examples] Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.
The materials and test methods used in the test are as follows.

I. Test material Vibration substrate: 0.8 mm thick steel plate Foamable thermosetting resin sheet (lower layer sheet) Prepared by mixing the foamable thermosetting resin composition in a Hobart mixer for 20 minutes at the compounding ratio shown in Table 1. Then, it was applied on a release paper with a predetermined thickness. This was heated at 120 ° C. for 90 seconds to prepare a sheet in which only the paste resin was semi-gelled.

Damping sheet (intermediate sheet) 1. Asphalt-based damping sheet (trade name: Melsheet, manufactured by Nippon Special Coating Co., Ltd.);

It is shown as type C of material in Table 4.

2. Foaming asphalt type vibration damping sheet (trade name: Melsheet, manufactured by Nippon Special Coating Co., Ltd.)

Restraint material sheet (upper layer sheet) A thermosetting composition having a composition ratio shown in Table 2 was melted and mixed in an autoclave heated to 200 ° C, and the resulting mixture was hot-pressed to a predetermined thickness. It was adjusted.

The thermosetting plastic sheet (F) was prepared by kneading the thermosetting resin composition having the compounding ratio shown in Table 3 with a roll to form a sheet having a predetermined thickness.

II. Test method (vibration damping performance test) Combining each spacer layer, damping sheet layer, and constraining sheet layer with a 150 x 300 mm, 0.8 mm thick steel plate (0.8 mm thick) to create a damping structure The loss factor of each structure is 20
It was measured at ℃, 40 ℃ and 60 ℃. For laminating and foaming each layer, a damping material and a restraining material were laminated on a steel plate, and heat treatment was performed in an oven under the condition of 150 ° C. × 30 minutes to fuse and foam each layer. The loss factor was calculated from the half-width of the mechanical impedance at the resonance point, and the loss factor at 200Hz was obtained by interpolation. The measurement frequency range is 1 to 1000 Hz.

The rigidity ratio was calculated based on the following formula.

Rigidity ratio = (f ₀ / f) ² · {(m ₁ + m ₂ ) / m ₁ } where f ₀ is the resonance frequency when a damping material or restraint material is attached, and f is the vibrating substrate 0.8 mm The resonance frequency of the thick steel plate, m ₁ is the mass per unit area of the steel plate, and m ₂ is the mass per unit area of the damping material and the restraining material.

III. Test structure and performance Table 4 shows the configurations and test results of the examples of the present invention and comparative examples.

As can be seen from the above test results, the structure of the present invention has excellent vibration damping characteristics and rigidity, and has an aptitude that is superior to the conventionally used vehicle structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a laminated structure for a vehicle according to the present invention before heat treatment, and FIG. 2 is a cross-sectional view of the same after heat treatment.
The figure is a cross-sectional view after heat treatment when a foamable asphalt-based vibration damping sheet is used as the vibration damping sheet (2). (1) …… Lower layer sheet, (2) …… Intermediate sheet, (3) …… Binding material sheet, (4) …… Vibration substrate.

Front page continued (72) Inventor Takamitsu Mikuni 1-2-1 Yokou, Kawasaki-ku, Kawasaki-shi, Kanagawa, Japan Zeon Corporation Research and Development Center (72) Inventor Yu Kagoshima 1-2 Yuko, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 1 ZEON Corporation R & D Center (72) Inventor Noboru Hino 1-2-1 Yokou, Kawasaki-ku, Kawasaki-shi, Kanagawa ZEON Corporation R & D Center (72) Inventor Horikawa Adult Chuo-ku, Tokyo Hatchobori 1-10-7 Zeon Kasei Co., Ltd.

Claims (5)

[Claims] 1. A foamable thermosetting resin sheet laminated on a vibration substrate in a vehicle, comprising a vinyl chloride resin, an epoxy resin, a plasticizer, an epoxy resin curing agent, and a foaming agent. From the lower layer sheet (1) in which the epoxy resin is 20 to 500 parts by weight and the vinyl chloride resin is in a semi-gelled state with respect to 100 parts by weight, and the vibration damping sheet laminated on the lower layer sheet (1) The intermediate sheet (2) and the restraining material sheet (3) laminated on the intermediate sheet, and the contact surfaces of these sheets and the vibration substrate are integrally fused by heating and the lower sheet (1 ) Is foamed, the laminated structure for vehicles. 2. The laminated structure for a vehicle according to claim 1, wherein the intermediate sheet (2) is made of an asphalt damping material. 3. The laminated structure for a vehicle according to claim 1, wherein the intermediate sheet (2) is made of a foamable asphalt damping material. 4. The laminated structure for vehicle according to claim 1, wherein the restraint material sheet (3) is a restraint material sheet containing a tackifier resin. 5. The restraint sheet (3) is made of a restraint material which is a thermosetting plastic sheet.
A laminated structure for vehicles as described.