JPH0453738A - Panel reinforcement sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a reinforcing sheet for metal panels, and more specifically, it has good processability such as punching, cutting, and winding, and has excellent reinforcing properties and heat insulation properties. , and a lightweight reinforcing sheet for metal panels.

(Prior Art) Metal panels have conventionally been used as structures in all industrial fields such as automobiles, buildings, and furniture.

Metal panels are difficult to replace with other materials due to their strength and durability, but they have problems such as being heavy due to their high specific gravity and poor insulation properties due to their good thermal conductivity. Ta. In recent years, from the perspective of saving capital and energy, vehicles,
In construction materials, efforts are being made to reduce the weight by thinning the plate thickness, but this reduces the strength.For example, in the case of car doors, the reduced strength of the area causes a lack of surface tension and rigidity. However, there are problems such as a lack of solidity as a part. In order to solve this problem,
No. 5-101659 proposes a method of using reinforcing material in the door panel. This method involves attaching a sheet made mainly of epoxy resin to a part of the panel and curing it in an automobile paint drying oven to reinforce the door.
This method has the problem that the reinforcing properties are insufficient if it is applied only to a part, and the purpose of weight reduction cannot be achieved if it is applied to the entire surface.

In addition, in order to prevent the inflow and outflow of heat from the outside in automobiles, building materials, etc., Gauss wool is used on the back of the panel.
Insulating materials such as felt and urethane foam are used. This method is effective for increasing the cooling effect and preventing dew condensation, but the insulation material is a pre-formed product and requires manual labor to install, but it is large and takes time. There was a problem.

JP-A-62-106432 discloses a method for manufacturing a vehicle outer panel structure that is lightweight, has heat insulation properties, and reinforcement properties. This is a sheet that is laminated with a first layer made of vinyl chloride resin, a second layer made of fiber cloth, and a third layer made of a metal thin film of 50μ or less, and then heated and foamed. , by curing
A method has been proposed that can provide reinforcement and heat insulation properties at the same time.

This method can be said to be an excellent technology in that it uses a single material, has multiple functions, and is lightweight. As the metal thin film exemplified in the detailed description, it is stated that among aluminium stainless steel, zinc, tin, nickel, copper, and iron, it is particularly desirable to use aluminum as the first layer.

However, in order to provide a higher level of reinforcing properties, it becomes necessary to increase the rigidity of the first layer material itself or to increase the thickness of the foil. However, it is inevitable that problems may occur when winding up the sheet, and the sheet that normally reinforces the panel has the property that it can be easily made into a long length) Cuttability (the property that it can be easily cut) is important. For example, 0.
To reinforce an 8 mm steel panel to a bending stiffness ratio of 3 or more, stainless steel or iron requires a foil with a thickness of 20μ or more, and aluminum, copper, or zinc requires a foil with a thickness of 50μ or more. It becomes necessary.

When a metal foil of this thickness was used as the second layer, there was a problem in that it could not be easily cut or rolled up.

(Problems to be Solved by the Invention) As a result of intensive research into a method for highly reinforcing panels, the present inventors found that by laminating a foam curable resin layer on a specific metal foil, a high degree of reinforcement was achieved. It also had heat insulating properties. It was discovered that a lightweight reinforcing sheet with excellent workability such as punching, cutting, and winding can be obtained, and the present invention was completed.

(Means for Solving the Problems) Thus, according to the present invention, 10
PVC resin, iron foil with a thickness of μ or more and 50 μ or less,
A panel reinforcing sheet is provided, which is characterized in that it is laminated by heating and foaming a composition comprising a plasticizer, a high-temperature foaming agent, an epoxy resin, and a heat-activated curing agent for epoxy resin.

The metal thin film provided in the present invention is a planar base material that supports a foamable composition, and is rigid and stretchable to facilitate application, transportation, and attachment of the foamable composition to a metal panel. It is necessary to have the characteristics of having a small amount of carbon dioxide (in addition to being flexible and lightweight). Foamed sheets are usually produced in long sheets, rolled up, and then punched and cut into regular shapes as necessary.

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

Generally, metal foil is produced by a rolling method.

Copper and aluminum with good stretchability are industrially produced up to a thickness of several microns. In recent years, rollable iron foils have begun to be produced, but their rollability is not very good, and those with a thickness of 50μ or more are mainly produced industrially. On the other hand, electroforming is a completely different method of producing metal foil; in other words, metal is electrodeposited onto a substrate (cathode drum) from an electrolytic solution containing metal ions, then peeled off from the substrate, and then continuously coiled. This is a manufacturing method in which the material is rolled up and is called the electrolytic method, electrodeposition method, or electroforming method. Industrial production of iron foil by electroforming only started a few years ago. Iron foil made by this electroforming method has a structure in which resinous crystal grains are densely aggregated, and compared to iron foil made by rolling method, it has no mechanical directionality and has a uniform thickness.5
It has the characteristics of being able to produce thin foils with a thickness of 0μ or less, being soft and easy to tear.Since it is essentially iron, it has several times the mechanical strength of aluminum or copper foil.

The electroformable iron foil used in the present invention makes very effective use of these advantages. In other words, the electroformable iron foil has high tensile strength and low tear strength, so it has excellent punching and cutting properties. , and a foil with a diameter of 50 μm or less has an elongation of about 3%, so the winding property is good. It is also highly economical. Rollable iron foil has too strong tear strength and is difficult to cut. Aluminum and copper foils have poor cutting and winding properties, so if you want to give them high reinforcing properties, you have to use thick ones. It is not possible to be sexually satisfied at the same time.

Electroformed iron fi (hereinafter referred to as electroformed iron foil) is 10μ or more5
The thickness must be 0μ or less; if the thickness is greater than this, the reinforcing properties can be improved, but the winding and cutting properties will be reduced. If it is less than 10μ, the reinforcing properties will be insufficient.

If necessary, electroformable iron foil plated with zinc, nickel, etc. can be used. These are effective in preventing rust.

The foamable resin composition used in the present invention contains at least a vinyl chloride resin, a plasticizer, a blowing agent, an epoxy resin, and a heat-activated curing agent for epoxy resin as essential components, and in addition, optional cell regulators, fillers, It is a composition consisting of a pigment, a heat stabilizer, a viscosity modifier, etc., and is formed into a sheet in advance at a temperature below the decomposition temperature of the blowing agent, and then heated at 120°C to 200°C in the next heating step. It foams and hardens through crosslinking of epoxy resin.

Vinyl chloride resins include not only vinyl chloride homopolymers, but also vinyl chloride, vinyl acetate, acrylic acid, methacrylic acid, acrylic esters, methacrylic esters,
Known copolymers with maleic acid, fumaric acid, maleic esters, phthalic esters, itaconic acid, vinylidene chloride, vinyl ether, etc. can be used alone or in combination. Vinyl chloride polymers (including copolymers) can be produced by any known method such as emulsion polymerization or suspension polymerization, but in particular, vinyl chloride polymers produced by emulsion polymerization or fine suspension polymerization for pastes can be used. It is preferable to use these materials alone or in combination with those obtained by suspension polymerization, from the viewpoint of ease of forming into a sheet and uniformity of the cell structure during foaming.

Examples of plasticizers include phthalate esters such as dioctyl phthalate and dibutyl phthalate, phosphate esters such as tricresyl phosphate, dioctyl adipate,
Fatty acid esters such as dioctyl sebacate, polyesters such as condensates of adipic acid and ethylene glycol, trimerites such as trioctyl trimellitate, chlorinated paraffins, alkylbenzenes, high molecular weight aromatics Known plasticizers for vinyl chloride such as these can be used alone or in combination. The blending amount of the plasticizer is not particularly limited, but it is more than 10 parts by weight and 15 parts by weight per 100 parts by weight of vinyl chloride.
It is preferable to blend in a range of 0 parts by weight or less. If the blending amount is 10 parts by weight or less, the expansion ratio will not improve, and if it exceeds 150 parts by weight, the hardness will not increase and the reinforcing effect will be reduced.

As the blowing agent, a high temperature decomposition type organic or inorganic blowing agent, a high temperature expansion type microcapsule, etc. are used.

As the organic blowing agent, azodicarbonamide, paratoluenesulfonylhydrazide, dinitrosopentamethylenetetramine, 4,4'-oxybisbenzenesulfonylhydrazide, etc. are used. The decomposition temperature of the organic blowing agent can be arbitrarily adjusted using urea, zinc compounds, lead compounds, etc. Examples of inorganic blowing agents include sodium bicarbonate and sodium borohydride. As the high temperature expansion type microcapsules, those in which low boiling point hydrocarbons are encapsulated with vinylidene can be used. Although any blowing agent can be used in the present invention, an organic blowing agent with a decomposition temperature of 100°C or higher is particularly preferable from the viewpoint of ease of forming into a sheet, appearance of the foam, uniformity of foaming, and density. If the decomposition temperature is below ℃, foaming may start when forming into a sheet, the resin may not be sufficiently melted during foaming in a heating furnace, and the foaming ratio may not increase due to degassing, or a uniform foam may not be obtained. Also, inorganic foaming agents and microcapsules can be used, but there are drawbacks in terms of foaming ratio and economic efficiency.
The amount of the blowing agent is preferably 0.5 to 15 parts by weight per 100 parts by weight of the vinyl chloride resin.
．． If it is less than 5 parts by weight, foaming will be insufficient, and if it exceeds 15 parts by weight, the degree of foaming will not change, and adding too much is economically wasteful.

Examples of epoxy resins that can be applied to the present invention include ordinary glycidyl ether type, glycidyl ester type, glycidyl amine type, linear aliphatic epoxide type, and aliphatic epoxide type epoxy resins, which can be used to form desired foams. They can be used alone or in combination depending on their physical properties. The epoxy resin is added in an amount of 20 to 500 parts by weight per 100 parts by weight of the vinyl chloride resin. If the blending amount was less than 20 parts by weight, a hard foam could not be obtained.
If less than 0.00 parts by weight is added, the heat generated during the curing reaction is large, causing problems such as decomposition of vinyl chloride and suppression of expansion by decomposed gas of the blowing agent, making it difficult to obtain a foam with a high expansion ratio.

As the heat-activated curing agent for epoxy resins, common curing agents that exhibit curing action when heated can be used. Preferred hardening agents include those 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 derivatives such as 2-n-heptadecyl imidacil, isophthalic acid dihydrazide, N,N-dialkyl urea derivatives, N
, N-dialkylthiourea derivatives, acid anhydrides such as tetrahydrophthalic anhydride, isophoronediamine, metaphenylenediamine, N-aminoethylpiperazine, boron trifluoride complex compounds, trisdimethylaminomethylphenol, and the like. Curing agents can be used alone or in combination as desired. The amount of the curing agent is preferably 1 to 20 parts by weight per 100 parts of the epoxy resin.If the amount is less than 1 part by weight, curing will be insufficient and the rigidity of the foam will be insufficient; Even if a large amount is added, the rigidity of the foam remains unchanged, and adding too much is economically wasteful.

The curing temperature here refers to the temperature of the medium at which the heat generated by curing reaches its peak when the mixture of epoxy resin and curing agent at room temperature is heated in an oil bath, heater, etc.

A preferred combination and amount of epoxy resin and curing agent depending on the heating conditions can be easily determined by testing in advance.

In the present invention, in addition to these essential ingredients, fillers such as calcium carbonate, talc, and clay, heat stabilizers,
Foam regulators, colorants, etc. can be added. The amount of each of the above ingredients is based on 100 parts by weight of vinyl chloride resin.
The filler is in the range of 0 to 200 parts by weight, the heat stabilizer is in the range of 0 to 10 parts by weight, and the foam regulator is in the range of 0 to 10 parts by weight. When blending each compounding agent, if the amount of filler exceeds 200 parts by weight, the fineness of foaming will be lost or the expansion ratio will not increase, and if the amount of filler exceeds 10 parts by weight, is also not effective.

The foamable resin composition applied to the present invention includes a vinyl chloride resin, a plasticizer, a blowing agent, an epoxy resin, a curing agent for epoxy resin, and, if necessary, a cell regulator, a filler, a heat stabilizer, Coloring agents and the like are added, and the mixture is homogenized and adjusted using a commonly known kneading machine.

Next, an example of a method for manufacturing a sheet according to the present invention will be described. When the above-mentioned foamable composition is a liquid, the liquid composition may be directly applied to the surface of the electroformed iron foil, heated and molded to a temperature below the temperature of the foaming agent, and then solidified. The liquid composition can also be continuously heated and formed into a sheet on release paper or a steel belt, and then laminated with electroformed iron foil. Using vinyl chloride resin for paste as vinyl chloride resin,
This is advantageous because it easily absorbs plasticizers and epoxy resins and solidifies when heated. Furthermore, if the composition is liquid, a laminate can be obtained without using any particular adhesive.

As another sheet manufacturing method, the mixed composition is formed into a sheet using a general sheet forming machine such as a calendar or extrusion.
After forming into a membrane, it is laminated with electroformed iron foil and crimped.
After bonding with adhesive or by dissolving vinyl chloride or epoxy resin with a solvent and mixing other ingredients,
It is also possible to apply it onto electroformed iron foil and then volatilize the solvent to form a sheet. These are advantageous when the mixed composition is solid before being formed into a sheet. Particularly preferred is a method in which a foamable composition in the form of plastisol is directly applied onto electroformed iron foil, and then heated and solidified at a temperature below the foaming temperature of the foaming agent.

When the sheet of the present invention is manufactured by each of the above-mentioned methods, tackiness will naturally develop on the resin composition surface.

This is presumed to be because the epoxy resin is not completely absorbed into the vinyl chloride resin particles and is released as an adhesive component on the surface. It is extremely effective because it does not require the use of agents or adhesives. Of course, in order to further increase the adhesiveness, it is also possible to add an adhesive component to the composition in advance or to apply the adhesive component to the surface of the resin layer. However, when producing sheets, in the winding process, the electroformed iron foil sticks to the surface side, causing problems during unwinding and impairing workability. Release-treated paper or plastic film, which is preferably laminated on the surface and rolled up, can be effectively used as a release film material.

A laminated sheet of electroformed iron foil, a foamable resin composition, and, if necessary, a release film material is a flexible sheet with high elasticity,
Rolling, cutting and punching can be done easily.

If a metal foil film other than electroformed iron foil is used, the winding performance or cutting performance will be poor, and the cut surface will be sharp, which may cause injury to the human body.

The sheet cut into a desired shape can be easily adhered to the panel to be reinforced by peeling off the release film material and pressing the resin layer surface against the panel to be reinforced.

Even if the panel has a curved surface such as a car roof or a winder, the sheet is flexible, so it can be applied evenly without trapping air bubbles or creating wrinkles.

It also has high barrier properties and a good appearance.

Next, a method for foaming and curing the sheet-forming composition will be described. The sheeted composition pasted on the exterior panel is passed through a heating furnace, foamed and cured.
An outer panel structure with improved heat insulation and strength is obtained.

Taking organic foaming as an example, the mechanism of foaming and hardening due to epoxy resin compounding can be considered as follows.

First, the vinyl chloride resin is melted by heating, and then the foaming agent is decomposed to generate gas, which causes the system to foam and form cells. Subsequently, the epoxy resin contained and dispersed in the composition undergoes a curing reaction by activation of the curing agent, and the foam becomes hard. Therefore, the properties of the foam formed are influenced by the gelation rate of the vinyl chloride resin, the decomposition rate of the blowing agent, and the curing rate of the epoxy resin, and it is necessary to select materials based on the target foam density and degree of curing. be.

For example, it is most rational to use an existing paint baking furnace as the heating furnace used when heating the adhesive after pasting it on the inner surface of a vehicle exterior panel. Paint baking furnaces can be broadly classified into undercoat baking furnaces, intermediate coating baking furnaces, and top coating baking furnaces, but intermediate coating baking furnaces or top coating baking furnaces are preferably used in the present invention.

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

As shown in Table 1, the electroformed iron foil used for the surface material of the sheet of the present invention has high strength but relatively low tensile strength and some elongation.
It is easy to roll up evenly without creases, is easy to cut and punch into desired shapes, and has soft edges.
No damage to the human body. When pasting on panels, it can be applied uniformly even to curved surfaces, and has a high reinforcing effect after heating and foaming and curing.Also, the resin layer foams and has a high heat insulation effect, so conventional reinforcing materials and heat insulation The work of pasting together materials individually can now be done with just the sheets of the present invention, resulting in resource and energy savings. Table 1 shows the mechanical properties of various metal foils.

In addition, the thermal insulation properties of the foam are closely related to the expansion ratio, and the higher the expansion ratio, the more gases such as air are included, and the thermal conductivity becomes lower, so the insulation properties improve. Table 1 shows the results of measuring the expansion ratio of the vinyl chloride foam obtained by the present invention and the thermal conductivity of the foam as indicators of heat insulation properties, and comparing them with conventional heat insulating materials. However, with this composition, it was difficult to increase the foaming ratio to 4 times or more due to restrictions on physical properties such as construction methods and heat resistance.However, with this composition, by increasing the foaming ratio to 4x or more, it is easy to create a foam with a high expansion ratio. It can be seen that the insulation properties can be obtained and exceed the level of insulation properties of conventional insulation materials.

Table 2* Felt tube (Felt H manufactured by Howa Senki Kogyo ■ (Example) The present invention will be explained in more detail with reference to Examples below. In addition, parts and percentages in Examples and Comparative Examples are specified unless otherwise noted. Unless otherwise noted, the measurements are based on weight.The physical properties of the four examples were evaluated according to the test method shown below.

After wrapping the sheet twice around a cylinder with a diameter of 150 m with the metal foil side facing outward, unwind it, observe the condition of the metal foil, and calculate the wrinkles per 1 m. Depending on the number (evaluated as follows.

(b) Cutting When a sheet in which metal foil, resin laminate, and release film material are laminated in this order is repeatedly cut to a length of 30 CI with a cutter knife from the release film material side at a constant load and speed. Judgment was made as follows based on ease of cutting and degree of cutter knife wear.

(c) Expansion ratio The thickness of the foamable composition of the laminated foamable sheet is a (
sn+), then paste the sheet on the panel,
The foam was cured at 150 to 160°C for 30 minutes in a hot air furnace, and the thickness b (v++) of the foam part was measured, and b/
a is the foaming ratio.

(d) The thermal conductivity of the foam was measured using a heat insulating thermal conductivity meter (manufactured by Anglo-French Seiki Co., Ltd., 1 (C-071H)) and used as an index of the heat insulating property.

(e) Reinforcement A foamable laminated sheet formed into a sheet with a thickness of IIIm is attached to a steel plate with a thickness of 0.81, and then a
Foam and harden in a hot air heating oven at °C for 30 minutes, JIS K
- Using the bending strength measuring device No. 6911, the path between the fulcrums 11
00+m, the bending strength was measured at a loading rate of 5 mm/win, and the load (yl) at the time of 21111 displacement was determined. The bending stiffness ratio y is calculated from the load (y, ) and yl during 2ms + displacement of the steel plate alone.

/yo was determined and used as an index of reinforcing property.

(f) After being attached to an exterior panel and foamed, the smoothness of the surface and the state of foaming were determined by visual observation.

Examples 1 to 5, Comparative Examples 1 to 4 The following blended composition (1) was prepared as a foamable composition.

Tree BN Example 1 is (a) to (f), Examples 2 to 5 and Comparative Example 1
-4 was blended with (a) to (su). However, the amount of (e) was 9 parts by weight only in Example 1 and 7 parts by weight in the others.

These compositions were applied to the surface of the metal foil shown in Table 3 to a thickness of 1 mm and heated in a hot air drying oven at 120'CX for 2 minutes.
A laminated sheet was obtained.

This sheet was tested for cuttability and windability according to the test method described above. Furthermore, after pasting the foam composition surface on a 0.8 mm thick iron plate, the foam was heated in a hot air oven at 150'C for 30 minutes to obtain a foam, and the foaming ratio, heat insulation properties, and reinforcing properties were measured using the above test method. did.

The results obtained are shown in Table 3.

When aluminum or copper foil is used, the reinforcing properties are poor, and increasing the reinforcing properties to a sufficient level requires thickening the foil, but with a film thickness of 80μ or more, processing such as winding and cutting properties is difficult. inferior in sex. Rolled iron foil has good reinforcing properties, but has drawbacks such as poor winding and cutting properties, whereas the sheet of the present invention has good reinforcing properties, cutting properties, and winding properties, and is easy to foam and harden. The appearance afterwards is also good.

Comparative Examples 5 to 9 In Comparative Examples 5, 6, and 8.9, Examples 1 to 5 were prepared using the compositions shown in Table 4 and for electrocast iron having the thickness shown in the table.
A laminate was obtained in the same manner as above. In the case of Comparative Example 7 using blended composition (1), the composition was heated to 70°C to be fluidized, coated on metal foil, and then cooled.
．． I made it 8-1. Examples 1 to 5 and Comparative Example 1
The test was conducted in the same manner as in 4. The results are shown in Table 5.

In Comparative Examples 5 to 7 using non-foamed compositions, the foam has a heat insulating function, and in Comparative Example 8, which lacks an epoxy resin and a heat-activated curing agent for epoxy resin, the foam partially deflates. The bending stiffness ratio is small. Comparative Example 9, which lacked a plasticizer, turned black due to thermal decomposition and blisters were seen everywhere.

Claims (1)

[Claims] A composition consisting of a vinyl chloride resin, a plasticizer, a high-temperature foaming agent, an epoxy resin, and a heat-activated curing agent for epoxy resin is heated onto an iron foil with a thickness of 10 μm or more and 50 μm or less obtained by electroforming. , a panel reinforcing sheet characterized by foaming and laminating.