JPH0622965B2 - Sheet for panel reinforcement - Google Patents

Description

TECHNICAL FIELD The present invention relates to a reinforcing sheet for a metal panel, and more particularly, it has excellent workability such as punching, cutting and winding, and is excellent in reinforcing property and heat insulating property. And a lightweight sheet for reinforcing a metal panel.

(Prior Art) Conventionally, metal panels have been used as structures in various industrial fields such as automobiles, buildings, and furniture. From the viewpoint of strength and durability, metal panels cannot be replaced with other materials, but there are problems such as heavy weight due to high specific gravity and poor heat insulation due to good thermal conductivity. It was In recent years, from the viewpoint of saving resources and energy, vehicles, building materials, etc. have been made thinner and lighter,
As a result, the strength is reduced, and, for example, in the case of a door of an automobile, the strength of the portion is reduced, resulting in insufficient surface tension and rigidity, resulting in a lack of a solid feeling as a component. In order to solve this problem,
Japanese Patent No. 01659 proposes a method of using a reinforcing material for a door panel. In this method, a sheet consisting mainly of epoxy resin is attached to a part of the panel and cured in a paint drying oven of an automobile to reinforce the door. There was a problem that the purpose of weight reduction could not be achieved if it was pasted on the entire surface because the property was insufficient.

In addition, in automobiles, building materials, etc., from the viewpoint of preventing the inflow and outflow of heat from the outside, on the back surface of the panel, Gauss wool,
Insulation materials such as felt and urethane foam are used. This method is effective as a method for enhancing the cooling effect and preventing dew condensation, but the heat insulating material is a pre-molded product and is manually attached, but it is large and takes a lot of time to work. There was a problem.

Japanese Unexamined Patent Publication No. 63-272515 proposes a method for manufacturing a vehicle outer panel structure which is lightweight and has both heat insulating properties and reinforcing properties. This is a vinyl chloride resin, a plasticizer, a high-temperature foaming foaming agent, an epoxy resin, a first layer composed of a composition containing a heat-activatable curing agent for epoxy resin as an essential component, and a second layer composed of a fiber cloth. , A sheet in which a third layer made of a metal thin film of 50 μm or less is laminated is attached to the back surface of the panel, and then heated to foam and cure, thereby providing the reinforcing property.
A method capable of simultaneously providing heat insulation has been proposed. It can be said that this method is an excellent technique in that it has a single material and has multi-functionality and is lightweight. Among the metal thin films exemplified in the detailed description, among aluminum, stainless steel, zinc, tin, nickel, copper and iron, it is preferable to use aluminum as the first layer.

However, in order to impart a higher level of reinforcement, it is necessary to increase the rigidity of the material of the first layer itself or to increase the thickness of the foil, in which case the sheet is processed, that is, cut or cut. , It is inevitable that problems will occur when rolling up, the sheet that normally reinforces the panel is cut from a long sheet to the required shape and then attached to the panel, so the sheet At the time of production, the winding property (the property that the winding is easy) and the cutting property (the property that the cutting is easy) are important characteristics. For example, when trying to reinforce a 0.8 mm iron panel to a bending rigidity ratio of 3 or more, a foil with a thickness of 20 μ or more is required for stainless steel or iron, and a thickness of 50 μ or more for aluminum, copper, zinc. You will need foil. When the metal foil of this thickness is used as the first layer, there is a problem that it cannot be easily cut and wound.

(Problems to be Solved by the Invention) The inventors of the present invention have earnestly studied a method for highly reinforcing a panel, and as a result, by laminating a foam curable resin layer on a specific metal foil, a high degree of reinforcement can be obtained. And also had a heat insulating property. It has been found that a lightweight reinforcing sheet having excellent workability such as punching and cutting and winding can be obtained, and the present invention has been completed.

(Means for Solving Problems) Thus, according to the present invention, 10 obtained by the electroforming method is used.
Vinyl chloride resin on iron foil with a thickness of μ or more and 50μ or less,
There is provided a sheet for reinforcing a panel, characterized in that a composition comprising a plasticizer, a high temperature foaming type foaming agent, an epoxy resin and a heat-activatable curing agent for an epoxy resin is heated, foamed and laminated.

The metal thin film used in the present invention is a sheet-like substrate that supports a foamable composition, and at the same time as improving workability such as application of the foamable composition, transportation, and easy attachment to a metal panel. The function of improving the surface strength and barrier properties of a foamed panel is required, and it is required to have the characteristics of being rigid, less stretchable, flexible and lightweight. The foamable sheet is usually produced by producing a long sheet, winding it, punching it into a regular shape and cutting it as needed.

The electroformed iron foil used in the present invention is the main subject of the present invention and will be described in detail.

Generally, metal foil is produced by a rolling method. Copper and aluminum having good drawability are industrially produced up to a thickness of several μ. In recent years, rolled iron foil has begun to be produced, but the rolling property is not so good, and those having a thickness of 50 μm or more are mainly industrially produced. On the other hand, electroforming is a completely different method of producing metal foil; that is, metal is electrodeposited on a substrate (cathode drum) from an electrolyte solution containing metal ions, which is peeled from the substrate and continuously coiled. It is a manufacturing method of winding up as, and is called an electrolysis method, an electrodeposition method, or an electroforming method. Industrial production of iron foil by electroforming has just begun a few years ago. The iron foil formed by this electroforming method has a structure in which resin-like crystal grains are densely aggregated, has no mechanical directionality as compared with the iron foil formed by a rolling method, and has a uniform thickness.
It is characterized by the ability to produce thin foils of μ or less, soft and easy to tear. Since it is essentially iron, it has mechanical strength several times that of aluminum or copper foil.

The electroformed iron foil used in the present invention utilizes these advantages extremely effectively, that is, since the electroformed iron foil has high tensile strength and low tear strength, it has excellent punchability and cutability. In addition, the foil having a thickness of 50 μm or less has an elongation of about 3% and thus has a good winding property. It is also highly economical. Tear strength of rolled iron foil is too strong and difficult to cut. If aluminum and copper are to be imparted with high reinforcement, they have to use thick ones and are inferior in cutability and windability.All of the other metal foils have high reinforcement and cutability. It is not possible to satisfy the productivity at the same time.

Electroformed iron foil (hereinafter referred to as electroformed iron foil) is 10μ or more and 50μ
It must have the following thickness: When the thickness is larger than this, the reinforcing property can be improved, but the winding property and the cutting property are deteriorated. If it is 10 μm or less, the reinforcing property becomes insufficient.

If necessary, electroformed iron foil plated with zinc, nickel or the like can be used. These are effective in preventing rust.

The foamable resin composition used in the present invention has at least a vinyl chloride resin, a plasticizer, a foaming agent, an epoxy resin, an epoxy resin as a heat-activatable curing agent as an essential component, and other optional cell regulators, fillers, A composition composed of a pigment, a heat stabilizer, a viscosity modifier, etc., which was previously molded into a sheet at a temperature not higher than the decomposition temperature of the foaming agent, and at a temperature of 120 ° C to 200 ° C in the next heating step. It can be foamed and 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. The vinyl chloride polymer (including a copolymer) may be prepared by any known method such as emulsion polymerization or suspension polymerization, but in particular, it is prepared by emulsion polymerization or fine suspension polymerization for a paste. It is easy to make a sheet by using one alone or in combination with one that is suspension polymerized,
It is preferable because of uniform cell structure during foaming.

Examples of the plasticizer include phthalates such as dioctyl phthalate and dibutyl phthalate, phosphates such as tricresyl phosphate, dioctyl adipate,
Fatty acid ester such as dioctyl sebacate, for example, polyester such as a condensate of adipic acid and ethylene glycol, trimellitic acid ester such as trioctyl trimellitate, chlorinated paraffin, alkylbenzene, known chloride such as high molecular weight aromatic The plasticizers for vinyl can be used alone or in combination. The blending amount of the plasticizer is not particularly limited, but vinyl chloride 100
It is preferable to blend in an amount of more than 10 parts by weight and 150 parts by weight or less with respect to parts by weight. If the blending amount is 10 parts by weight or less, the foaming ratio does not improve, and if it exceeds 150 parts by weight, the hardness does not increase and the reinforcing effect decreases.

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. As the organic foaming agent, 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. Examples of the inorganic foaming agent 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 will start when it is formed into a sheet, or the resin will not melt sufficiently when foaming in a heating furnace, gas will not escape and the expansion ratio will not rise, and a uniform foam will be obtained. Hateful. In addition, although inorganic foaming agents and microcapsules can also be used,
There are difficulties in terms of expansion ratio and economy. The blending amount of the foaming agent is preferably 0.5 to 15 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. If the compounding amount is less than 0.5 parts by weight, the foaming is insufficient, and even if it exceeds 15 parts by weight, the foaming degree does not change, and excessive addition is economically useless.

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 epoxy resin is added in an amount of 20 to 500 parts by weight based on 100 parts by weight of vinyl chloride resin. Compounding amount is 20
If it is less than 5 parts by weight, it is difficult to obtain a hard foam, and if it exceeds 500 parts by weight, the heat generated during the curing reaction is large, so that decomposition of vinyl chloride occurs or expansion of the foaming agent due to decomposition gas is suppressed, resulting in high magnification. There is a problem that it is difficult to obtain the 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 preferable 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. As the curing agent, for example, dicyandiamite, 4,4 ′
-Diaminodiphenyl sulfone, imidazole derivatives such as 2-n-heptadecyl imidazole, isophthalic dihydrazide, N, N-dialkylurea derivatives, N, N-
Examples thereof include dialkylthiourea derivatives, acid anhydrides such as tetrahydrophthalic anhydride, isophoronediamine, metaphenylenediamine, N-aminoethylpiperazine, boron trifluoride complex compounds, and trisdimethylaminomethylphenol. The curing agents can be used alone or in combination as desired. The compounding amount of the curing agent is preferably 1 to 20 parts by weight with respect to 100 parts by weight of the epoxy resin. If the blending amount is less than 1 part by weight, the rigidity of the foam will be 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 will 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, calcium carbonate, talc, filler such as clay, heat stabilizer,
A bubble regulator and a coloring agent can be added. The blending 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 based on 100 parts by weight of the vinyl chloride resin. . In case of adding each compounding agent, if the amount of the filler exceeds 200 parts by weight, the fineness of foaming is lost, the expansion ratio does not increase, and the amount of the heat stabilizer and the bubble regulator is more than 10 parts by weight. Is not effective.

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

Next, an example of the method for producing the sheet used in the present invention will be described. When the foamable composition is a liquid, the liquid composition may be directly applied to the surface of the electroformed iron foil, heat-formed below the temperature of the foaming agent, and solidified. The liquid composition may be continuously heat-molded on a release paper or a steel belt to form a sheet, and then laminated with an electroformed iron foil. Using a vinyl chloride resin for paste as the vinyl chloride resin is advantageous because it easily absorbs the plasticizer or the epoxy resin and solidifies by heating. If it is a liquid composition,
A laminate can be obtained without using an adhesive.

As another sheet manufacturing method, using a general sheet forming machine such as a calendar or extrusion of the mixed composition,
After forming into a film, it is laminated with electroformed iron foil and pressed,
After adhering with an adhesive or dissolving vinyl chloride or epoxy resin with a solvent and mixing other compounding agents,
A method is also possible in which a solvent is volatilized to form a sheet after coating on an electroformed iron foil. These are advantageous, for example, when the mixed composition before being formed into a sheet is a solid. Particularly preferred is a method in which a foamable composition in the form of plastisol is directly applied onto an electroformed iron foil, and heated and solidified at a temperature not higher than the foaming temperature of the foaming agent.

When the sheet of the present invention is produced by each of the above methods, the resin composition surface naturally exhibits tackiness. It is presumed that this is because the epoxy resin was not completely absorbed in the vinyl chloride resin particles and the epoxy resin was liberated as an adhesive component on the surface. It is extremely effective because there is no need to use an agent or an adhesive. Of course, it is also possible to add an adhesive component to the composition in advance in order to further increase the adhesiveness, or to apply the adhesive component to the surface of the resin layer. However, in the case of producing a sheet, in the winding step, it sticks to the surface side of the electroformed iron foil and causes problems during rewinding, which deteriorates workability. Paper or plastic film that has been subjected to a release treatment can be effectively used as a release film material, which is preferably laminated on the surface and wound up.

The sheet in which the electroformed iron foil, the foamable resin composition, and the release film material as necessary are laminated is a flexible sheet rich in elasticity,
Winding, cutting and punching can be done easily. If a metal foil film other than the electroformed iron foil is used, the winding property or cutting property is poor, the cutting surface becomes sharp, and the human body may be damaged.

The sheet cut into a desired shape can be easily adhered by peeling off the release film material and then pressing the resin layer surface against the panel to be reinforced. Even if the panel is a car roof or a curved surface like a fender, the seat has flexibility, so it does not entrap air bubbles or generate wrinkles,
It can be applied evenly. It also has a high barrier property and a good appearance.

Next, a method for foaming and curing the above sheet composition will be described. The composition formed into a sheet attached to the outer panel is passed through a heating furnace, foamed and cured,
An outer panel structure having improved heat insulation and strength is obtained.

The mechanism of foaming and hardening by compounding an epoxy resin is considered as follows, taking organic foaming as an example. First, by heating, the vinyl chloride resin is melted, and then the foaming agent is decomposed to generate gas. The evolved gas causes the system to foam and form cells. Subsequently, the epoxy resin contained and dispersed in the composition causes a curing reaction due to activation of the curing agent, and the foam is hardened. Therefore, the characteristics of the foam that is formed are affected by the gelation rate of the vinyl chloride resin, the decomposition rate of the foaming agent, and the curing rate of the epoxy resin, and it is necessary to select the material based on the target foaming density and curing degree. is there.

For example, it is most rational to use an existing paint baking furnace as a heating furnace to be used after heating after being attached to the inner surface of a vehicle outer panel. The coating baking furnace is roughly classified into an undercoat baking furnace, an intermediate coating baking furnace, and an overcoat baking furnace. The intermediate coating baking furnace or the overcoat baking furnace is preferably used in the present invention.

(Effects of the Invention) Thus, according to the present invention, it is possible to easily obtain a high-strength, heat-insulating, lightweight lightweight reinforcing sheet having excellent cutting, punching and winding properties as compared with the prior art.

The electroformed iron foil used for the surface material of the sheet of the present invention has high strength as shown in Table 1 but has relatively low tear strength and a slight elongation.
It does not easily fold and can be wound up evenly, and it is easy to cut and punch into the desired shape, and the end face is soft.
Does not damage the human body. Even when it is attached to the panel, it can be attached evenly on a curved surface, and has a high reinforcing effect after heat foaming and curing. Moreover, since the resin layer foams and has a high heat insulating effect, it is conventionally used as a reinforcing material and heat insulating material. The work of bonding the materials individually is sufficient only for the sheet of the present invention, and resource saving and energy saving can be achieved. Table 1 shows the mechanical properties of various metal foils.

Further, the heat insulating property of the foam has a close relationship with the foaming ratio, and the higher the foaming ratio, the more the gas such as air is contained and the smaller the thermal conductivity, so the heat insulating property is improved. Table 2 shows the expansion ratio of the vinyl chloride foam obtained according to the present invention and the thermal conductivity of the foam, which were measured as an index of heat insulation and compared with the conventional heat insulating material. However, it was difficult to increase the expansion ratio to 4 times or more due to restrictions on physical properties such as the construction method and heat resistance. On the other hand, in the present composition, by setting the expansion ratio to 4 times or more, it is easy to obtain a high expansion ratio. It can be seen that the heat insulating property of the conventional heat insulating material can be exceeded.

(Example) Hereinafter, the present invention will be described more specifically with reference to Examples. Parts and% in Examples and Comparative Examples are based on weight unless otherwise specified. The physical properties of each example were evaluated according to the following test methods.

Test method (a) Winding property The sheet is placed in a cylinder with a diameter of 150 mm with the metal foil side facing outwards.
After being heavily wound, it was rewound and the state of wrinkles of the metal foil was observed, and the number of wrinkles per 1 m was evaluated as follows.

(B) Cutting A sheet obtained by laminating a metal foil, a resin laminate, and a release film material in this order is repeatedly cut from the release film material side with a constant load and speed for a length of 30 cm with a cutter knife. Judgment was made as follows from the ease of cutting and the degree of abrasion of the cutter knife.

(C) Foaming ratio The thickness of the foamable composition of the laminated foaming sheet is a (m
m) and then attach the sheet to the panel, 150
Foam was cured in a hot-air heating furnace at ˜160 ° C. for 30 minutes, the thickness b (mm) of the foam portion was measured, and b / a was taken as the foaming ratio.

(D) Thermal insulation The thermal conductivity of the foam was measured with a thermal conductivity meter (HC-071 H, manufactured by Eiko Seiki Co., Ltd.) and used as an index of thermal insulation.

(E) Reinforcing property A foamable laminated sheet formed into a sheet having a thickness of 1 mm is attached to a steel plate having a thickness of 0.8 mm, and then at 150 to 160 ° C. for 3 days.
Foam-hardened in a hot air heating furnace for 0 minutes, using the bending strength measuring device of JIS K-6911, distance between fulcrums 100 mm, load speed 5
Measure the bending strength in mm / min and obtain the load (y ₁ ) at a displacement of 2 mm. The bending rigidity ratio y ₁ / y ₀ was calculated from the load (y ₀ ) and y _{1 of the} steel sheet alone when it was displaced by 2 mm and used as the index of the reinforcing property.

(F) The surface smoothness and foaming state after foaming after being attached to the exterior panel were evaluated by visual observation.

Examples 1-5, Comparative Examples 1-4 The compounding compositions shown below were prepared as foamable compositions.

(A) Zeon 47 (Nippon Zeon Co., Ltd., vinyl chloride paste resin) 100 parts by weight (b) Dioctyl phthalate (Sanken Kako Co., Ltd., plasticizer) 40〃 (c) AZ-M1 (Otsuka Chemical Co., Ltd.) , Organic foaming agent) 7 〃 (d) Epicoat # 828 (Yukaka Shell Epoxy Co., Ltd., liquid epoxy resin) 150 〃 (e) Dicyandiamide (Nippon Carbite Co., Ltd., curing agent for epoxy resin) 7 or 9 weight Part (f) FL-23 (Adeka Argus Co., Ltd., heat stabilizer) 3 parts by weight (g) DP Hardener (Maruwa Biochemical Co., Ltd., curing accelerator for epoxy resin) 4.0 〃 (H) Whiten H ( Shiraishi Industry Co., Ltd., filler) 30 〃 (ri) BAP-1 (Adeka Argus Co., Ltd., bubble control agent) 2 〃 Example 1 is (a) to (f), Examples 2 to 5 and Comparative Examples 1
No. 4 to (I) to (R) were blended. However, the amount of (e) was set to 9 parts by weight only in Example 1 and 7 parts by weight for the others.

These compositions were applied to the surface of the metal foils shown in Table 3 to a thickness of 1 mm and heated in a hot air drying oven at 120 ° C. for 2 minutes to obtain laminated sheets.

This sheet was tested for cuttability and windability according to the test method described above. Further, after the surface of the foamed composition was pasted on a 0.8 mm thick iron plate and heated in a hot air oven at 150 ° C. for 30 minutes to obtain a foamed body, the expansion ratio, heat insulation and reinforcement were measured by the above-mentioned test methods. . The results obtained are shown in Table 3.

When aluminum or copper foil is used, the reinforcing property is inferior, and if the reinforcing property is raised to a sufficient degree, it is necessary to increase the film thickness of the foil, but if the film thickness is 80μ or more, processing such as winding property and cutting property is performed. Inferior in nature. Rolled iron foil has good reinforcing properties, but has drawbacks such as poor winding property and cutting property, whereas the sheet of the present invention has good reinforcing property, cutting property, winding property, foaming, and curing. The appearance afterwards is also good.

Comparative Examples 5-9 Using compositions having the compositions shown in Table 4, in comparison with electroformed irons having the thicknesses shown in the table, Comparative Examples 5, 6, 8 and 9 show Examples 1-5.
A laminate was obtained by the same operation as. In the case of Comparative Example 7 in which the compounded composition was used, the composition was heated to 70 ° C. to be fluidized, applied on a metal foil, and then cooled so that the resin layer had a thickness of 0.8 mm. did. Examples 1-5 and Comparative Example 1
The test was conducted in the same manner as in ~ 4. The results are shown in Table 5.

Comparative Examples 5 to 7 in which the non-foaming composition was used did not have a heat insulating function, and Comparative Example 8 lacking the epoxy resin and the heat-activatable curing agent for the epoxy resin was a state in which the foam partially collapsed. However, the bending rigidity ratio is small. Comparative Example 9 lacking a plasticizer was blackened due to thermal decomposition, and blisters were observed everywhere.

Claims (1)

[Claims] 1. A 10 μm or more, 50 obtained by electroforming method.
A composition comprising a vinyl chloride resin, a plasticizer, a high-temperature foaming foaming agent, an epoxy resin, and a heat-activatable curing agent for an epoxy resin is heated and foamed on an iron foil having a thickness of μ or less, and laminated. A sheet for panel reinforcement.