JPH0452773B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reinforcing adhesive sheet.

Conventionally, various reinforcing measures have been applied to car body steel plates in automobiles and the like. For example, roof,
For outer panels that are relatively wide and flat but thin, such as fenders, hoods, trunks, quarter panels, and doors, it is necessary to provide appropriate structural rigidity against external forces, so metal reinforcement is used. The method used is to attach the inner plate made of parts by spot welding or adhesive. However, this method has drawbacks such as the heavy weight of the metal reinforcing members, which goes against the trend of thinner outer panels designed to reduce the weight of car bodies, increases weight and costs, and complicates the installation process. It had

In addition, for the purpose of damping and reinforcing the outer skin of the vehicle, polymeric materials such as asphalt rubber, epoxy resin, acrylic resin, phenolic resin, and unsaturated polyester resin are applied to the back side of the outer skin in a considerable thickness and over a considerable area. Coating or pasting methods are also known.
In this method, the rigidity is said to be proportional to the cube of the thickness, so by increasing the thickness, it is possible to increase the rigidity, but the increase in weight and cost due to the increase in the amount of resin increases. It has the same drawbacks as the metal reinforcing member.

In view of such conventional circumstances, the inventors
Previously, we proposed a reinforcing adhesive sheet that is lightweight, inexpensive, and can significantly improve the rigidity of objects to which it is attached.
56-36575). That is, it is a bead that is formed on one side of an uncured or semi-cured thermosetting reinforcing resin sheet containing a reinforcing material and has a width narrower than that of the sheet and forms a bead-shaped bulge before the sheet is cured. A forming material is attached to the sheet, and a hem portion of the sheet protruding from the bead forming material forms a mounting surface for an object to be mounted.

By the way, when the object to be reinforced is an automobile body, in consideration of workability, a reinforcing adhesive sheet is pasted before the baking process of the top coat, especially before the electrodeposition coating, and then heated and cured in a paint baking oven after the electrodeposition coating. It is preferable to let However, unlike after electrocoating, there may be a small amount of lubricant or anti-corrosion oil attached to the car body before electrocoating, and this may cause the car body to be coated with reinforcing adhesive sheets. In the case of the reinforcing adhesive sheet with the above structure, the bead forming material tends to harden while pushing up the thermosetting reinforcing resin sheet, and voids tend to be formed around the bead-shaped bulges. It is in. Therefore, the portion of the vehicle body corresponding to the gap around the bead-shaped bulge is exposed. In other words, no electrodeposition paint was applied to this part. Therefore, if it is subsequently left in a humid atmosphere, rust will develop in the bare, unpainted portion, which may cause a serious defect if the object to be reinforced is an automobile exterior panel.

Therefore, the inventors developed a reinforcing adhesive sheet to solve the above-mentioned drawbacks by using this sheet on one side of a first thermosetting reinforcing resin sheet in an uncured or semi-cured state containing a reinforcing material. A bead-forming material that forms a bead-like bulge is applied to the thin sheet before it hardens, and
A second thermosetting reinforcing resin sheet in an uncured or semi-cured state that covers this bead forming material is added to the first thermosetting resin sheet.
We proposed a reinforcing adhesive sheet laminated to a thermosetting reinforcing resin sheet.

By using the reinforcing adhesive sheet having the above structure, the object to be reinforced can be effectively bonded to the entire surface of the second thermosetting reinforcing resin sheet, and the bead forming material can be bonded to the object to be reinforced using the first thermosetting resin sheet. Even if a gap is created in that area by pushing up the reinforcing resin sheet, the second
Since the thermosetting reinforcing resin sheet is in close contact with the surface of the object to be reinforced, the surface of the object will not be exposed, thereby minimizing the occurrence of rust.

However, according to subsequent research by the inventors, the rust-preventing effect of the reinforcing adhesive sheet described above may be insufficient depending on the amount of oil such as rust-preventive oil adhering to the car body before electrodeposition coating. I found that there are cases where this is sufficient. That is, when the amount of oil such as the above-mentioned rust preventive oil attached is small, when the bead forming material pushes up the first thermosetting reinforcing resin sheet, the second thermosetting reinforcing resin sheet is not reinforced. The first resin sheet slides on the second resin sheet while remaining in close contact with the surface of the steel plate of the vehicle body, and is pushed up with a deviation between the second resin sheet and the steel plate. Since there are no bare parts on the surface, rust is prevented from forming.

However, if there is a large amount of oil such as the above-mentioned rust preventive oil attached, when the first thermosetting reinforcing resin sheet is pushed up by the bead forming material, the second thermosetting reinforcing resin sheet While in close contact with the first resin sheet, it slides on the car body steel plate and shrinks, leaving a part of the car body steel plate exposed that should originally be covered with the second resin sheet, which may cause rust to occur in this part. There is sex.

The present invention was made to solve the above-mentioned drawbacks, and its gist is that on one side of a first thermosetting reinforcing resin sheet in an uncured or semi-cured state containing a reinforcing material, A bead forming material having a narrower width than this sheet and forming a bead-shaped bulging portion is applied before the sheet is cured, and a second thermosetting material in an uncured or semi-cured state covers this bead forming material. A reinforcing adhesive sheet characterized in that a thermosetting reinforcing resin sheet is laminated on the first thermosetting reinforcing resin sheet via a sheet-like base material.

According to the reinforcing adhesive sheet with the above structure, it is lightweight and inexpensive, and not only significantly improves the rigidity of the object to be attached, but also has a further improved rust prevention effect compared to the previously proposed reinforcing adhesive sheet. is obtained.

That is, the reinforcing adhesive sheet of this invention is
As mentioned above, since the second resin sheet is laminated to the first resin sheet via the sheet-like base material,
Even when reinforcing an object to which oil such as anti-rust oil is attached, such as a car body steel plate, if the reinforcing adhesive sheet of the present invention is used, when the bead forming material pushes up the first resin sheet, the first resin sheet The second resin sheet remains in close contact with the surface of the object to be reinforced, and the first resin sheet slides on the surface of the sheet-like base material and is pushed up with a deviation between it and the second resin sheet. Therefore, there will be no bare parts on the surface of the object to be reinforced, and rust will be prevented as much as possible.

In the reinforcing adhesive sheet according to the present invention, the first and second resin sheets are made of a thermosetting resin composition. The temperature varies largely depending on the resin composition, that is, the types and amounts of the resin, curing agent, and other ingredients.

The inventors initially developed a resin composition that would have a tensile modulus as large as necessary and sufficient to improve the rigidity of a metal plate such as an outer panel of a car body, and would raise the glass transition temperature as described above. When we prepared a thermosetting resin composition and tried reinforcing a metal plate with it, the reinforcing effect was satisfactory, but depending on the type and thickness of the metal plate, distortion of the metal plate due to curing shrinkage may occur. There was no escaping the problem. Conversely, a thermosetting resin composition is prepared in which the tensile modulus is insufficient to improve the rigidity of the metal plate and the glass transition temperature is low. When we tried reinforcing the plate, we found that the distortion of the metal plate due to curing shrinkage hardly appeared in this case.
It was found that the intended purpose of reinforcement could not be achieved depending on the type and thickness of the metal plate.

However, the above-mentioned contradictory problems can also be solved by using a first thermosetting reinforcing resin sheet in which a reinforcing material is embedded and which has a high tensile modulus after heat curing and a high glass transition temperature after heat curing, and a first thermosetting reinforcing resin sheet that is laminated thereon and heated. The second thermosetting reinforced resin sheet, which has a low tensile modulus after curing and a low glass transition temperature after heat curing, can suppress generation of distortion in the metal plate.

In a preferred embodiment of the reinforcing adhesive sheet according to the present invention, the first thermosetting reinforcing resin sheet has a tensile modulus of elasticity necessary and sufficient to improve the rigidity of the metal plate after heating and curing. In Although,
This tensile modulus is generally ^about 30 to 500Kg/mm2,
Moreover, the glass transition temperature is 80°C or higher and usually up to 200°C. If this elastic modulus becomes too large and the glass transition temperature becomes too high, distortion may occur depending on the type, thickness, and shape of the metal plate, despite the presence of the second thermosetting reinforcing resin sheet. There is a possibility that it will not be possible to prevent the occurrence.

In addition, in this specification, tensile modulus is
Using the method specified in ISO Recommendation R-527, using a Type 1 test piece,
It means the value measured by B.

On the other hand, the second thermosetting reinforced resin sheet has a tensile modulus after heat curing that is insufficient to improve the rigidity of the metal plate and a glass transition temperature that is low. What is elastic modulus in general?
Approximately 0.1 to 22Kg/ ^mm2 , and glass transition temperature is 70℃
Below, the temperature is usually up to 0°C. If this modulus of elasticity becomes too small or the glass transition temperature becomes too low, the reinforcing effect will be poor depending on the type, thickness, and shape of the metal plate.

A further preferred embodiment of the reinforcing adhesive sheet of the present invention is that the first thermosetting reinforcing resin sheet has a two-layer structure. In other words, the first
The resin sheet has a two-layer structure of an inner layer on the bead forming material side and an outer layer on the exposed surface side, and the outer layer has a higher tensile modulus after heat curing than the inner layer and the second thermosetting reinforcing resin sheet. It is also characterized in that the glass transition temperature after heat curing is high.

Also in this case, similarly to the above embodiment, the outer layer can increase the rigidity of the metal plate, and the inner layer and the second resin sheet can suppress the occurrence of distortion in the metal plate. Furthermore, the second resin sheet that is completely adhered to the metal plate to be reinforced not only prevents rust from forming, but also increases the adhesion area and improves adhesiveness.

In this case, the tensile modulus after heat curing is 30 to 500 Kg/mm ² for the outer layer of the first resin sheet, 0.1 to 22 Kg/mm ² for the inner layer and the second resin sheet, and the glass transition after heat curing is The temperature is higher than 80℃ in the outer layer of the first resin sheet and usually up to 200℃, and the temperature in the inner layer and the second resin sheet is
The temperature of the resin sheet is below 70℃, usually up to 0℃.

Furthermore, if the reinforcing adhesive sheet is pasted on a metal plate and then electrocoated, the paint will not adhere to the interface of the metal plate at the periphery of the adhesive sheet, and this area will also cause rust. It may happen.
Therefore, the above-mentioned second resin sheet or this and the first
By making the inner layer of the resin sheet conductive, it is possible to suppress the occurrence of rust, which is more effective in achieving the main purpose of the present invention, which is to prevent rust.

The above-mentioned first and second thermosetting reinforcing resin sheets each preferably contain an epoxy resin as the thermosetting resin, and a heat-activated curing agent is blended therein, and various additives are added as necessary. It can be formed by adding and forming a sheet in an uncured or semi-cured state according to a conventional method.
Of course, thermosetting resins other than epoxy resins can also be used.

When forming this sheet, the first and second thermosetting resins can be cured by appropriately setting the type of thermosetting resin, the type of curing agent and other additives, or by setting the blending amount of each component. The tensile modulus and glass transition temperature of the reinforced resin sheet after heat curing are adjusted as described above.

Epoxy resins that are preferably used to form each resin sheet include various epoxy resins such as the usual glycidyl ether type, glycidyl ester type, glycidyl amine type, linear aliphatic epoxide type, and alicyclic epoxide type. Depending on the physical properties of the composition layer, one type can be used alone or two or more types can be used in combination.

Further, as the heat-activated curing agent for the above-mentioned epoxy resin, any ordinary curing agent that exhibits curing action by heating may be used, and in general, it is sufficient if it is active in the temperature range of 80 to 200°C, such as dicyandiamide,
4,4'-diaminodiphenylsulfone, 2-n-
Imidazole derivatives such as heptadecyl imidazole, isophthalic acid dihydrazide, N·N-dialkyl urea derivatives, N·N-dialkylthiourea derivatives, etc. are used. The amount used may be generally 1 to 15 parts by weight per 100 parts by weight of the epoxy resin.

In addition to the above-mentioned epoxy resins and curing agents, various additives are used to give the composition enough cohesive strength to enable sheet molding, to prevent sagging, or to lower melt viscosity and improve wettability. Additives are used as necessary.

For example, in order to improve sheet forming ability,
Thermoplastic resins such as polyvinyl butyral, polyamide, polyamide derivatives, polyesters, polysulfones, polyketones, high molecular weight epoxy resins derived from bisphenol A and epichlorohydrin, butadiene-acrylonitrile copolymers or derivatives thereof can be blended. The amount of these used is preferably about 5 to 100 parts by weight per 100 parts by weight of the epoxy resin.

In addition, fillers such as calcium carbonate, talc, asbestos, silicic acids, carbon black, and colloidal silica are used to prevent the composition from sagging. The amount to be blended is usually about 10 to 300 parts by weight per 100 parts by weight of the epoxy resin. In addition, reactive diluents such as butyl glycidyl ether and monoglycidyl ether of long-chain alcohols, for the purpose of lowering the melt viscosity and improving wettability,
Phthalate plasticizers such as dioctyl phthalate,
A phosphoric acid plasticizer such as triclean diphosphate can be added. These amounts are epoxy resin
The amount is usually about 5 to 30 parts by weight per 100 parts by weight.

Among the first and second thermosetting reinforcing resin sheets formed in this way, it is particularly desirable that the second resin sheet has adhesive properties in its normal state. This is because temporary adhesion before heat curing becomes easier when applied to a metal plate. Of course, the first resin sheet may also have adhesive properties. In particular, when making the second resin sheet narrower than the first resin sheet,
It is preferable that the first resin sheet has adhesive properties. In this case, when a two-layer structure is used, inside and outside, it is sufficient that only the inner layer has adhesiveness.

Furthermore, a reinforcing material is embedded in the first resin sheet in order to enhance the reinforcing effect of the metal plate. When this first resin sheet has a two-layer structure, an inner layer and an outer layer, a reinforcing material is generally embedded in the outer layer. Examples of this reinforcing material include inorganic fiber cloth made of glass fiber or asbestos fiber, organic fiber cloth made of linen, cotton, nylon, polyester, polypropylene, etc., plastic film such as polyester film or nylon film, paper such as kraft paper, etc. Nonwoven fabrics made of polyester fibers, polypropylene fibers, etc., aluminum, iron,
There are metal foils made of copper, zinc, etc.

In order to embed the reinforcing material, when molding the first resin sheet, one or both surfaces of the reinforcing material may be coated with or impregnated with a thermosetting resin composition. Among the above-mentioned reinforcing materials, inorganic fiber cloth is preferred since it can be impregnated on one side and a sufficiently large reinforcing effect can be obtained, and glass fiber cloth is particularly preferably used.

The thickness of the first and second thermosetting reinforcing resin sheets explained above varies depending on the type of metal plate and the degree of reinforcement, but in general, the thickness of the first resin sheet is preferably 0.2 to 40 mm. is 0.5~20mm,
When this sheet has a two-layer structure, inside and outside, the outer layer
Approximately 0.01 to 10 mm, preferably 0.1 to 5 mm, 0.1 for the inner layer
~30mm, preferably 0.5~10mm, and the overall thickness is usually around 0.2~40mm, preferably 0.5~20mm
It is. In addition, the second resin sheet generally has a
30mm, preferably 0.5-10mm.

Next, the bead forming material, which is another important component of the reinforcing adhesive sheet of the present invention, is a foamable resin sheet, which has the property of foaming when heated above the decomposition temperature of the foaming agent contained therein. Examples include those having the following. In addition, there are flattened products that are molded from a tube-like body and can be deformed almost back to the tube-like shape by heating, and flattened products that are molded from non-tube-like bodies such as rods and films and are deformed into a stretched shape at least in the vertical direction by heating. A heat-recoverable material such as a flattened material that can be substantially restored to the above-mentioned non-tubular body can also be used. Furthermore, it is a flattened product in which an elastic foam containing a fixing agent in the void is flattened and this flattened state is maintained by the fixing agent, and is a resilient foam that can be restored to the original foam by heating. Flattened products can also be used.

Among these, preferred are expandable resin sheets and flattened resilient foams, and flattened resilient foams are particularly preferred.

Such a foamable resin sheet is made by adding, for example, various thermosetting or thermoplastic polymers to a foaming agent and, if necessary, a foaming aid, a curing agent, a curing accelerator,
After blending the crosslinking agent, crosslinking aid, filler, coloring agent, stabilizer, etc., and kneading this mixture using a mixing roll, etc., the temperature conditions are such that the blowing agent does not decompose (slight decomposition is fine). It can be made by sheet molding according to the conventional method.

Examples of the thermosetting or thermoplastic polymer used above include thermosetting resins such as epoxy resins, phenolic resins, and polyester resins, polyethylene, ethylene-vinyl acetate copolymers, and adhesive polyolefins. The foaming agent may be any foaming agent that foams during heat curing of the reinforced resin sheet and does not foam during sheet molding, such as azo compounds, nitroso compounds, hydrazide compounds, and the like.

The thickness of the above foamable resin sheet is usually 0.2~
5 mm, preferably about 0.5 to 2 mm,
Further, it is desirable that the foaming ratio after heating is practically 2 to 30 times.

The above-mentioned flattened resilient foam is produced by impregnating the voids of an elastic foam with a fixing agent, softening or melting the fixing agent under heating, and then flattening the elastic foam by compression or the like. It can be obtained by solidifying the fixing agent by cooling etc. in a flattened state, and when this flattened product is heated, the fixing agent softens or melts and returns to the original foam with good dimensional stability. be able to.

The above-mentioned elastic foam means that when the foam itself is compressed and deformed by an external force, the external force disappears, regardless of whether or not the polymer material itself that forms the foam has elasticity. It is sufficient that the condition can be recovered to the above condition.

In addition, the foaming state of the above elastic foam is as follows:
An open-cell type is preferable because it allows the adhesion agent to be contained in the voids and is easy to flatten, but if the adhesion agent can be included to an extent that maintains the flattened state, closed cells may be mixed in some parts. You may do so. The apparent density of this foam is usually 0.5 or less, and the lower limit is about 0.005.
A more preferable range is 0.02 to 0.3.

If this apparent density is too high, even if the foam is flattened, the volume will decrease only slightly, and since there are few voids, it will not be possible to contain the adhesive necessary to maintain the flattened state, which is undesirable. ,
On the other hand, if it is too low, the mechanical properties of the foam, that is, the ability to restore and deform the flattened tube body to the original tube shape are deteriorated, which is not preferable.

The elastic foam described above can be manufactured using various polymers and various known methods.
The polymer used is not particularly limited as long as it can form an elastic foam having the above-mentioned functions, and examples include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyurethane, and rubber.

The above-mentioned fixing agent is a resin that softens or melts when heated and can solidify when cooled. This adhesive needs to have a melting point or softening point lower than that of the foam, and is generally preferably 10° C. or more higher than room temperature.

As this adhesive, various resins can be used as long as they have the above-mentioned melting point or softening point, such as thermosetting resins such as epoxy resins, phenolic resins, and polyester resins, polyethylene, polypropylene, polyamide, and polyester resins. Examples include thermoplastic resins such as butyral. Furthermore, various additives such as plasticizers and fillers may be added to these resins to adjust the viscosity during melting and to reduce costs.

Alternatively, a thermosetting resin with a curing agent added may be used as the adhesive, and the adhesive may be cured after the flattened foam is restored to its original foam form by heating. According to this, the hardness and strength of the restored foam can be adjusted.

The flattened resilient foam obtained using the above-mentioned elastic foam and adhesive usually has a thickness of 0.1~
It is preferable to use a material that can be restored to a foamed material with a thickness of about 3 mm to 30 mm by heating.

The sheet-like base material, which is another important component of the reinforcing adhesive sheet of this invention, is preferably one that does not soften when heated for bead formation.
Woven fabrics and non-woven fabrics made of glass fiber, organic fiber fabrics made of hemp, cotton, nylon, polyester, polypropylene, etc., plastic films such as polyester films and nylon films, non-woven fabrics made of polyester fibers, polypropylene fibers, etc., aluminum, iron, copper. , metal foil made of zinc, etc. Among these, woven or nonwoven fabrics made of glass fiber, which have good flexibility and heat resistance, are particularly preferred. The thickness of this sheet-like base material is usually about 0.01 to 1 mm.

In the reinforcing adhesive sheet of the present invention, the bead forming material is formed on one side of the first thermosetting reinforcing resin sheet (on the inner layer side in the case of a two-layer structure), to have a width narrower than that of the sheet. Further, the second thermosetting reinforcing resin sheet is laminated and integrated with the sheet via the sheet-like base material so as to cover the bead forming material. This lamination and integration may be performed by utilizing their adhesive properties, or may be fused by heating to an extent that the curing does not proceed completely. Further, it is usually preferable to laminate the sheet-like base material and the second resin sheet in advance by means such as fusion bonding before this lamination and integration.

In the reinforcing adhesive sheet of the present invention, a protective film may be attached to the exposed surface side of the first thermosetting reinforcing resin sheet. This protective film provides the following effects.

First, when a reinforcing adhesive sheet with a protective film is stored as a tape-like roll before use, the protective film functions as a separator, causing problems such as interlayer adhesion. On the other hand, when reinforcing using this sheet, the protective film is directly applied to the door outer panel surface, etc. without peeling, so a troublesome peeling operation is not necessary, and good results can be obtained in speeding up the reinforcing work.

Secondly, since this protective film is provided on the door outer panel surface etc. as a part of the reinforcing layer after heating and curing, it is expected that this will improve the reinforcing effect, while the above-mentioned first resin sheet Since the resin sheet is provided so as to cover the entire surface, it gives good results to the moisture resistance of the resin sheet and prevents deterioration of the reinforcing effect over time. Therefore, a more reliable reinforcing layer can be formed.

The protective film has various functions as described above, and is made of a polymer material with excellent strength, moisture resistance, heat resistance, etc., and has a thickness of 0.001 to 0.5 mm, preferably 0.003 to 0.5 mm.
Those molded to a thickness of about 0.1 mm are used.
A particularly suitable polymer material is polyester film, but various other films such as polyethylene film, nylon film, polyvinyl chloride film, and polypropylene film can also be used.

Preferred properties of the reinforcing adhesive sheet of the present invention obtained in this way include that the first and second thermosetting reinforcing resin sheets do not substantially flow at room temperature and have self-retention properties; , the overall viscosity is high. This sheet has flexibility and pliability, and even when bent 250 to 300 degrees, the sheet does not show any damage and can be restored to its original state. Therefore, according to this preferred embodiment, the material to be reinforced (metal plate) has shape conformability.
It can be applied even if it is wavy, mountain-shaped, square, curved, etc., and can be applied more effectively as a reinforcing sheet.

FIG. 1 shows an example of the reinforcing adhesive sheet of the present invention, in which 1 is a first thermosetting reinforcing resin sheet in an uncured or semi-cured state containing a reinforcing material, and 2 is the sheet 1. The above sheet 1 is attached to
A narrower bead forming material 3 is a second thermosetting reinforcing resin sheet laminated on the first resin sheet 1 so as to cover the bead forming material 2 via a sheet-like base material 4. be.

The reinforcing adhesive sheet described above is attached to the back surface 6a of the automobile door outer panel 6 from the mounting surface 3a of the second resin sheet 3, as shown in FIG. 5 is a reinforcing material embedded in the first resin sheet 1;
a and 1a are the adhesive surfaces of the first resin sheet. By heating the reinforcing adhesive sheet after installation, the viscosity of the reinforcing adhesive sheet temporarily decreases and the installation surface further adheres to the door outer panel 6, while the bead forming material 2 foams or forms as shown in FIG. is restored and its cross section becomes larger, and the first resin sheet 1 is pushed up from the second resin sheet 3 and its adhesive surfaces 1a, 1a, and a bead-shaped bulge 1b is formed before it hardens. As the heating progresses, the first and second resin sheets 1 and 3 are cured.

Moreover, FIG. 4 shows the installed state of another example of the reinforcing adhesive sheet of the present invention, in which the first thermosetting reinforcing resin sheet 1 containing the reinforcing material 5 is in an uncured or semi-cured state. However, when the reinforcing material 5 is embedded and provided on a metal plate as an object to be reinforced and heated and hardened, the tensile modulus becomes a necessary and sufficient magnitude to improve the rigidity of the metal plate, and when the reinforcing material 5 is heated and hardened. The outer layer 1c has a resin composition that has a high glass transition temperature, and the same tensile modulus as above is made to be insufficient to improve the rigidity of the metal plate, and the glass transition temperature after heat curing is low. The structure is the same as that shown in FIG. 2, except that the inner layer 1d has a resin composition as follows.

In addition, in FIGS. 2 and 4, the second thermosetting reinforcing resin sheet 3 preferably has a lower tensile strength after heat curing than the first thermosetting reinforcing resin sheet 1 in FIG. The elastic modulus is small and the glass transition temperature is low, and in FIG. 4, the structure has a small tensile elastic modulus and a low glass transition temperature similar to the inner layer 1d of the first thermosetting reinforced resin sheet 1. It is.

Typical objects to be reinforced using the reinforcing adhesive sheet of the present invention are metal plates, especially car body steel plates such as the outer panels of automobiles, but also various other vehicles, washing machines, home appliances such as televisions, etc. It can be widely applied to metal plates that are generally considered to be thin plates, such as metal plates.

The reinforcing method using the reinforcing adhesive sheet of the present invention includes pressing the adhesive sheet onto the back side of the metal plate as described above, such as a steel plate for a car body, and
This can then be achieved by heat treatment using a conventional heating method, such as a hot air circulation heating furnace, an infrared heating furnace, a high frequency induction heating furnace, or the like. Note that the above heat treatment can be performed simultaneously in the paint baking process for car body steel plates in an automobile manufacturing line.

As described in detail above, the present invention provides a method of forming a bead shape on one side of an uncured or semi-cured thermosetting reinforcing resin sheet in which a reinforcing material is embedded, the width of which is narrower than that of the sheet, and before the sheet is cured. A bead forming material forming the bulging portion is attached, and a second thermosetting reinforcing resin sheet in an uncured or semi-cured state covering the bead forming material is attached to the first thermosetting reinforcing resin sheet. The gist is a reinforcing adhesive sheet that is laminated via a shaped base material, which is pressed onto the object to be reinforced in a specific state and heated to harden while forming a bead-like bulge. Not only can a great reinforcing effect be obtained just by using this method, but the construction is also extremely simple, and in particular, the rust prevention properties can be improved.

Next, examples of this invention will be described. In the following, parts shall mean parts by weight.

Example 1 50 parts of Epicote #828 (bisphenol A type liquid epoxy resin manufactured by Yuka Shell Co., Ltd.), 35 parts of Epicote #1002 (bisphenol A type solid epoxy resin manufactured by Yuka Shell Co., Ltd.), Byron #500 (Toyobo Co., Ltd.) 15 parts of polyester resin manufactured by Co., Ltd., Kyuazol
Epoxy resin composition consisting of 1 part of 2MZ-AZINE (latent curing agent for epoxy resin manufactured by Shikoku Kasei Co., Ltd.), 5 parts of dicyandiamide (latent curing agent for epoxy resin manufactured by Nippon Carbide Co., Ltd.), 50 parts of talc, and 5 parts of asbestos powder. The resulting resin mass was kneaded using a regular mixing roll, and the resulting resin mass was pressed to a thickness of 0.5 using a direct pressure press.
mm, and further laminated with glass cloth (WE-22D-104 manufactured by Nittobo Co., Ltd.) to obtain an uncured first thermosetting reinforced resin sheet.

The tensile modulus of this first resin sheet after heat curing is 95Kg/ ^mm2 , and the glass transition temperature is 110℃.
It was hot. However, the heat curing conditions are 150℃ and 60℃.
It is a minute.

Next, 80 parts of Epicoat #871 (dimer acid-modified epoxy resin manufactured by Yuka Ciel Co., Ltd.), 5 parts of Epicoat #1002 (mentioned above), and 5 parts of Epicoat #828 (mentioned above)
and 10 parts of Hiker CTBN 1300 x 8 (nitrile rubber manufactured by BF. Gudryutsch) were melt-mixed in a mixing pot, and 100 parts of the resulting composition was added with Kyuazol.
2MZ-AZINE (above) 1 part, dicyandiamide (above) 5 parts, graphite (chuetsu graphite manufacturing scale graphite CPB-3) 75 parts and asbestos powder 3
After blending and kneading with a normal mixing roll, this was formed into a sheet shape with a direct pressure press to obtain a second uncured thermosetting reinforced resin sheet with a thickness of 0.4 mm. Ta.

Note that when this second resin sheet was heated and cured under the same conditions as the first resin sheet, the tensile modulus was 4.0 Kg/mm ² and the glass transition temperature was 50°C.

A glass nonwoven fabric (EP4012 manufactured by Nippon Vilene Co., Ltd.) having a thickness of about 0.07 mm was laminated onto this second resin sheet.

Separately, 100 parts of polyethylene (Sumikasen G801, manufactured by Sumitomo Chemical Co., Ltd.), foaming agent (FE-9, manufactured by Eiwa Kasei Co., Ltd.)
Eight parts were uniformly kneaded using a mixing roll, pelletized using a pelletizer, and then formed into a sheet using an extrusion molding machine to obtain a foamable sheet with a thickness of 1 mm.

Next, the first thermosetting reinforcing resin sheet is cut into a 5 cm width, and the foamable sheet cut into a 1cm width is attached to this, and the foamed sheet is further covered with the foamed sheet. A reinforcing adhesive sheet of the present invention was obtained by laminating a glass nonwoven fabric onto the resin sheet No. 2 and pasting it to the first resin sheet via the glass nonwoven fabric.

This reinforcing adhesive sheet was pressure-bonded to a 0.8 mm thick steel plate coated with antirust oil (Nippon Oil Co., Ltd. P-1400) so that the second thermosetting reinforcing resin sheet was on the steel plate side. After this pressure bonding, electrodeposition coating is applied and the temperature is 180℃.
The mixture was heated for 30 minutes in an atmosphere of When a strength test was conducted using the steel plate reinforced in this way as a test piece by the method described below, the maximum bending stress was 35
Kg/50mm width, and the maximum bending stress of the steel plate alone was 9Kg/50mm width, but it was found that an extremely excellent reinforcing effect was obtained.

Next, a rust test was performed on the cured sample using a salt spray tester (Model ST-JR manufactured by Toyo Rika Kogyo Co., Ltd.), and it was found that the electrodeposition coating properties at the interface between the steel plate and the reinforcing adhesive sheet were good, and the glass A second thermosetting reinforcing resin sheet laminated with non-woven fabric was provided to prevent the second sheet from shifting when the reinforcing sheet was heated after electrodeposition coating, so no rust occurred after 500 hours of salt water spraying. Ta.

Example 2 50 copies of Epicote #828 (listed above), 35 copies of Epicote #1002 (listed above), 15 copies of Byron #500 (listed above),
An epoxy resin composition consisting of 2 parts of DP-hardener (latent curing agent for epoxy resin manufactured by Maruwa Biochemical Co., Ltd.), 5 parts of dicyandiamide (mentioned above), 50 parts of talc, and 3 parts of asbestos powder is kneaded using a normal mixing roll. Then, the obtained resin mass was formed into a sheet with a thickness of 0.5 mm using a direct pressure press, and further laminated with glass cloth (same as in Example 1) to form the first thermosetting resin in an uncured state. This was used as the outer layer of the reinforced resin sheet.

Next, 80 parts of Epicort #871 (mentioned above), 5 parts of Epicort #1002 (mentioned above), and Epoxy #828 (mentioned above).
5 parts of Hiker CTBN1300×8 (mentioned above) and 10 parts of Hiker CTBN1300×8 (mentioned above) were melt-mixed in a mixing pot, and 100 parts of the obtained composition was added with 2 parts of DP-hardener (stated above), 5 parts of dicyandiamide (stated above), and graphite. (mentioned above) and 3 parts of asbestos powder were mixed together using a regular mixing roll, and then formed into a sheet using a direct pressure press to form an uncured sheet with a thickness of 0.4 mm. An inner layer of the thermosetting reinforced resin sheet of No. 1 was obtained. This was bonded to the outer layer of the first thermosetting reinforcing resin sheet to obtain a first thermosetting reinforcing resin sheet.

The tensile modulus of the outer layer and inner layer of this thermosetting reinforced resin sheet after heat curing is 95 for the outer layer.
Kg/mm ² , and 3.8 Kg/mm ² in the inner layer. Further, the glass transition temperature was 110°C in the outer layer and 50°C in the inner layer. However, the heat curing conditions are 150°C for 60 minutes.

Next, the first thermosetting reinforcing resin sheet having a two-layer structure was cut into a 5 cm width, and a foam sheet cut into a 1 cm width (same as in Example 1) was placed on the inner layer side of the first resin sheet. ) was attached. In addition, a second sheet was formed using a direct pressure press to form a sheet of exactly the same resin composition as that used for this inner layer to a thickness of 0.4 mm.
A glass nonwoven fabric (EP4012 manufactured by Nippon Vilene Co., Ltd.) is laminated on a thermosetting reinforcing resin sheet, and the glass nonwoven fabric side is attached to the inner layer side of the first thermosetting reinforcing resin sheet to which the foamable sheet is attached. This was used to make a reinforcing adhesive sheet.

A test piece was prepared using this reinforcing adhesive sheet in the same manner as in Example 1 above, and a strength test was conducted using the method described below. As a result, the maximum bending stress was
The maximum bending stress of the steel plate alone was 9Kg/50mm width, but it was found that an extremely excellent reinforcing effect was obtained.

Next, a rust test was conducted on the above test piece in the same manner as in Example 1, and it was found that the electrodeposition coating properties at the interface between the steel plate and the reinforcing adhesive sheet were good, and the second thermosetting layer laminated with the glass nonwoven fabric was Since the reinforcing resin sheet was provided to prevent the second sheet from shifting when the reinforcing sheet was heated after electrodeposition coating, no rust occurred after 500 hours of salt water spraying.

Example 3 While vibrating a 10 mm thick urethane foam (apparent density 0.02, open cell type, melting point 340°C), 60 mesh passes of polyamide powder (trade name: Platamide H-103, manufactured by Nippon Roussin Co., Ltd.) was applied to the entire void of the foam. ,
(melting point 80-90℃) in an amount of 150g/ ^m2 ,
This foam was heated to 150° C. and immediately flattened through a cooling roll to obtain a flattened resilient foam with a thickness of 1.0 mm.

A reinforcing adhesive sheet of the present invention was obtained in the same manner as in Example 2, except that this flattened material was cut into 1 cm width pieces and used instead of the foamable resin sheet.

Example 1 above using this reinforcing adhesive sheet
A test piece was prepared in the same manner as above, and a strength test was performed using the method described below, and the maximum bending stress was 45
Kg/50mm width, and the maximum bending stress of the steel plate alone was 9Kg/50mm width, but it was found that an extremely excellent reinforcing effect was obtained.

Next, the above test piece was subjected to the same rust test as in Example 1, and it was found that the electrodeposition coating properties at the interface between the steel plate and the reinforcing adhesive sheet were good, and no rust occurred even after 500 hours of salt water spraying. Ta.

<Strength test> A supporting stand with two vertical flat plates (width 50 mm), each of which has an inverted U-shaped cross section with a radius of curvature of 5 mm, arranged in parallel with a distance of 100 mm between the tips, was made to have a width of 50 mm. The test piece was supported horizontally, and the maximum bending stress (Kg/50 mm width) was measured when a load was applied from the top to the center of the test piece using a vertical flat plate (width 50 mm) exhibiting a U-shaped cross section with a radius of curvature of 10 mm.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of the reinforcing adhesive sheet of the present invention, FIG. 2 is a cross-sectional view showing the reinforcing adhesive sheet of FIG. 1 before heating, and FIG.
This figure is a cross-sectional view showing the state of the adhesive sheet shown in FIG. 2 after heating, and FIG. 4 is a cross-sectional view showing the installed state of another example of the reinforcing adhesive sheet of the present invention. 1... First thermosetting reinforcing resin sheet, 2...
Bead forming material, 3... second thermosetting reinforcing resin sheet, 4... sheet-like base material, 5... reinforcing material.

Claims (1)

[Scope of Claims] 1. On one side of the first thermosetting reinforcing resin sheet in an uncured or semi-cured state containing a reinforcing material, a bead-like expansion layer is formed which has a narrower width than this sheet and before the sheet is cured. At the same time, the bead forming material that forms the protrusion is attached, and the second thermosetting reinforcing resin sheet in an uncured or semi-cured state that covers this bead forming material is passed through the sheet-like base material to the first thermosetting resin sheet. A reinforcing adhesive sheet characterized by being laminated on a reinforcing resin sheet. 2. The reinforcing adhesive sheet according to claim 1, wherein the sheet-like base material is a glass woven fabric or a glass nonwoven fabric. 3. The first thermosetting reinforcing resin sheet has a higher tensile modulus after heat curing and a higher glass transition temperature after heat curing than the second thermosetting reinforcing resin sheet. Reinforcing adhesive sheet according to item 1 or 2. 4. Any one of claims 1 to 3, wherein at least the second thermosetting reinforcing resin sheet among the first thermosetting reinforcing resin sheet and the second thermosetting reinforcing resin sheet has electrical conductivity. The reinforcing adhesive sheet described in .