JPS60222240A - Adhesive sheet for reinforcing - 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] This invention relates to an adhesive sheet for reinforcement.

Conventionally, various reinforcing measures have been applied to car body steel plates in automobiles and the like. For example, for outer panels that are relatively wide and flat but thin, such as roofs, fenders, hoods, trunks, quarter panels, and doors, it is important to have appropriate structural rigidity against external forces. Due to necessity, a method is used in which an inner plate made of a metal reinforcing member is attached by spot welding or adhesive. However, with this method, the weight of the metal reinforcing members is heavy, and this goes against the trend of thinning the outer skin, which was designed to reduce the weight of car bodies.
This has disadvantages such as increased cost and complicated installation process.

In addition, in order to both dampen and reinforce 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 increasing the thickness can increase the rigidity, but it also increases the weight and cost due to the increased amount of resin. It had the same drawbacks as the metal reinforcing member.

In view of this conventional situation, the present inventors have developed a reinforcing adhesive sheet that is lightweight, inexpensive, and significantly improves the rigidity of the attached object by embedding a reinforcing material in a thermosetting resin composition. We have already proposed a reinforcing adhesive sheet in which a flattened material is attached to one side of a sheet-like prepreg, which is formed from a tubular body, can be transformed back into a tubular shape by heating, and has a narrower width than the prepreg. are doing.

This reinforcing adhesive sheet is applied to the back side of the object to be reinforced from the side to which the flattened material is applied by heating it.
The flattened product is deformed substantially into a tube shape, and the prepreg is pushed up and hardened to form a rib structure.

In the above method, the rigidity and strength are greatly improved compared to the method of pasting and curing a sheet-like material having a uniform thickness.

Note that it is also possible to attach uncured or semi-cured prepreg to a tubular body to form ribs in advance, then directly adhere it to the object to be reinforced and heat cure it.
In this case, adhesive workability is poor, especially on uneven surfaces. On the other hand, the reinforcing adhesive sheet described above does not have this drawback.

The above-mentioned tubular body is a relatively flexible material with a wall thickness of about 1.0 to 5 mm, such as a polymer molded product, which can generally be obtained using an extrusion molding machine. In order to obtain a sufficient reinforcing effect by heating the flattened product and restoring it to its original tubular shape, a method of crosslinking the tubular body is adopted.

Irradiation with ionizing radiation such as electron beams and gamma rays, or irradiation with ultraviolet rays is particularly effective as a crosslinking treatment method, but a crosslinking agent or a crosslinking accelerator is mixed and kneaded in advance during the manufacture of the tubular body. There is also a method of heating and crosslinking using these compounding agents.

However, there is a problem in that crosslinking treatment using ionizing radiation irradiation or ultraviolet ray irradiation increases the cost, and crosslinking treatment using the above-mentioned crosslinking agent or this and a crosslinking accelerator requires setting the blending ratio of these ingredients and There has been a problem in that it is difficult to set the heating conditions, and therefore it is difficult to provide a sufficient heat recovery function to the flattened product, and as a result, a sufficient reinforcing effect cannot be obtained in many cases. .

On the other hand, the inventors have developed a thermosetting resin composition as a reinforcing adhesive sheet different from the above-mentioned reinforcing adhesive sheets, which is lightweight and inexpensive, and which significantly improves the rigidity of the attached object. We have already proposed a reinforcing adhesive sheet in which a foamable resin sheet that can be foamed by heating and has a narrower width than the prepreg is attached to one side of the prepreg, which is a sheet-like prepreg made by embedding a reinforcing material in the prepreg. are doing. However, with this reinforcing adhesive sheet, the height of the foam formed by heating the above-mentioned foamable resin sheet may not be uniform if the heating temperature changes, resulting in variations in the reinforcing effect. It had drawbacks.

This invention was made with the aim of solving the above-mentioned drawbacks, and its gist is to provide a sheet-like thermosetting resin prepreg in which a reinforcing material is embedded, and one side surface of this prepreg. The flattened material has a narrower width than this prepreg attached to the prepreg, and this flattened material has a tube body including an adhesive layer in the hollow part that is flattened integrally with this adhesive layer, and this flattened state is the same as that of the adhesive layer. The reinforcing adhesive sheet is held by a reinforcing adhesive sheet, wherein the adhesive layer becomes a foam by heating and can restore and deform the tube body to its original tube shape.

According to the reinforcing adhesive sheet of the present invention, it is lightweight and inexpensive, and the rigidity of the object to be mounted can be further improved stably compared to the above-mentioned reinforcing adhesive sheets that have already been proposed.

That is, the adhesive sheet for reinforcing of the present invention is applied from the side to which the flattened material is attached to the back side of the object to be reinforced by heating, so that the adhesive layer of the flattened material becomes a foam and the object is flattened. The tube body is deformed back to its original shape, and the prepreg is pushed up and hardened to form a rib structure.

The flattened tube body itself does not need to have the property of restoring its shape to a tube shape when heated, and does not intentionally require crosslinking treatment.

In addition, the flattened tube body is completely and stably restored to its original tube shape, and
Since the hollow portion of the restored and deformed tube body is filled with foam, an excellent reinforcing effect can be stably obtained.

The reason why the above-mentioned stable reinforcing effect is obtained is that the flattened product is composed of the tube body and the adhesive layer, and the restoring deformation of the tube body is performed by making the adhesive layer into a foam. In other words, while the flattened product can be deformed back to its original state by the action of the adhesive layer regardless of the heat recovery function of the tube body itself, during this deformation, the tube body prevents excessive deformation due to the foaming of the adhesive layer and the ribs. This is because it plays the role of keeping the height constant.

The above-mentioned thermosetting resin prepreg can be obtained, for example, by applying a thermosetting resin composition from both sides of a reinforcing material, or by forming the above thermosetting resin composition into a sheet shape, and applying this to a reinforcing material. It can be obtained by integrating the two using a laminating method or the like. All of these have a one-layer prepreg structure, but a preferred embodiment of the reinforcing adhesive sheet of the present invention is a case where the prepreg has a two-layer structure and the object to be reinforced is a metal plate.

That is, in the reinforcing adhesive sheet according to the present invention, the prepreg is composed of a thermosetting resin composition, but this type of composition mainly has a tensile modulus and a glass transition temperature after being heated and cured. It varies greatly 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, there may be problems with distortion of the metal plate due to curing shrinkage. There was no escape. 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, but depending on the type and thickness of the metal plate, the intended purpose of reinforcement could not be achieved. I understand.

However, the above-mentioned conflicting problems also arise when the first thermosetting resin composition layer has a reinforcing material embedded therein and has a high tensile modulus after heat curing and a high glass transition temperature after heat curing, and the first thermosetting resin composition layer is laminated thereon. A prepreg is constituted by a second thermosetting resin composition layer having a low tensile modulus after heat curing and a low glass transition temperature after heat curing, and the second thermosetting resin composition layer in this prepreg. Attach the above-mentioned flattened material formed narrower than this prepreg to the side, and paste so that the side of the prepreg to which the flattened material is attached is in contact with the metal plate,
In a preferred embodiment of the prepreg in the reinforcing adhesive sheet according to the present invention, that is, in the case of a two-layer structure,
The first thermosetting resin composition layer has a tensile modulus after heat curing of a size necessary and sufficient to improve the rigidity of the metal plate, and has a high glass transition temperature,
This tensile modulus is generally about 30 to 500 kg/-,
Further, 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 resin composition layer. There is a risk that it will not be possible to prevent this.

In addition, in this specification, tensile modulus is 150
Using the method specified in Recommendation R-527, using a Type test piece, 5pe
It means the value measured by edH.

In addition, when the above prepreg has a two-layer structure, the second trajectory hardening #J resin button embroidery layer constituting the prepreg has a tensile modulus of elasticity after heat hardening that is insufficient to improve the rigidity of the metal plate. Although it is large in size and has a low glass transition temperature,
The tensile modulus is generally about 0.1 to 22 h/-, and the glass transition temperature is 70°C or lower, usually up to 0°C. If this elastic modulus 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.

For the first and second thermosetting resin composition layers, epoxy resin is preferably used 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 an agent 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, 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 curable resin composition layer after heat curing are adjusted as described above.

Epoxy resins preferably used for forming each composition layer include various epoxy resins such as ordinary glycidyl ether type, glycidyl ester type, glycidyl amine type, linear aliphatic epoxide type, and alicyclic epoxide type. Depending on the physical properties of each 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, 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'-diaminodiphenyl Sulfone, 2-
Imidazole derivatives such as n-heptadecyl imitasol, isophthalic acid dihydrazide, N-N-dialkyl urea derivatives, N-N-dialkylthiourea derivatives, etc. are used.

The amount used is usually 1 to 100 parts by weight of epoxy resin.
The proportion may be 15 parts by weight.

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, for the purpose of improving sheet forming ability, polyvinyl butyral, polyamide, polyamide derivatives, polyester, polysulfone, polyketone, bisphenol A
Thermoplastic resins such as high molecular weight epoxy resins derived from 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 blending amount may be generally about 10 to 300 parts by weight per 100 parts by weight of the epoxy resin.

Furthermore, in order to lower the melt viscosity and improve wettability,
Reactive diluents such as butyl glycidyl ether and long-chain alcohol monoglycidyl ether, phthalic acid plasticizers such as dioctyl phthalate, phosphoric acid plasticizers such as triclean diphosphate, and the like can be blended. The amount of these components is usually 5 to 30 parts by weight per 100 parts by weight of the epoxy resin.

Among the first and gi2 thermosetting resin composition layers formed in this way, it is particularly desirable that the second thermosetting resin composition layer has tackiness in its normal state. This is because temporary adhesion before heat curing becomes easier when applied to a metal plate. Of course, the first thermosetting resin composition layer may also have adhesive properties.

Furthermore, a reinforcing material is embedded in the first thermosetting resin composition layer in order to enhance the reinforcing effect of the metal plate.

Examples of this reinforcing material include inorganic fiber cloth made of glass fiber or asbestos fiber, organic fiber cloth made of hemp, cotton, nylon, polyester, polypropylene, etc., plastic film such as polyester film or nylon film, paper such as kraft paper, etc. Examples include nonwoven fabrics made of polyester fibers and polypropylene fibers, and metal foils made of aluminum iron, copper, zinc, etc.

To embed the reinforcing material, when forming the first thermosetting resin composition layer into a sheet, one or both surfaces of the reinforcing material may be coated with or impregnated with the thermosetting resin composition. . Among the above-mentioned reinforcing materials, inorganic fiber cloth is preferable because it can obtain a sufficiently large reinforcing effect by impregnation on one side, and it is particularly preferable to use glass fiber cloth. A preferred embodiment of the prepreg in the sheet is one in which the first thermosetting resin composition layer and the second thermosetting resin composition layer as described above are laminated and integrated. This may be done by utilizing its tackiness, or it may be heated to such an extent that curing does not proceed completely. The thickness of this sheet varies depending on the type of metal plate and the degree of reinforcement, but generally the thickness of the first thermosetting resin composition layer is 0.01. ~1
(about 1+#+, preferably 0.1 to 5 degrees, about 0.1 to 30 degrees in the second thermosetting resin composition layer, preferably 0.5 degrees)
~10 baits, and the thickness of the entire prepreg is usually 0.2 ~
The amount is about 40 pieces, preferably 0.5 to 20 pieces.

Another important component of the reinforcing adhesive sheet according to the present invention is a flattened material having a narrower width than the prepreg described above. In this flattened product, a tube body including an adhesive layer in a hollow portion is flattened integrally with this adhesive layer, and this flattened state is maintained by the adhesive layer, and the adhesive layer becomes a foam when heated. The tube body can be transformed back into its original tube shape.

The tube body referred to here usually has a wall thickness of approximately 0.1 to 51 mm.
It is a material having a relative flexibility of about 1#1, such as a polymer molded product, and can generally be obtained using an extrusion molding machine. Polymers used to manufacture this tube body include polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, polyvinyl chloride, ethylene-propylene-terpolymer, nitrile rubber, butyl rubber, acrylonitrile-butadiene-styrene rubber, etc. can be mentioned. In addition, fillers, pigments,
Anti-aging agents and stabilizers may be added. Although this tube body intentionally does not require cross-linking treatment, it is subjected to the same cross-linking treatment as in the past, giving the tube body in the above-mentioned flattened product the property that it can be deformed almost back to its original tube shape by heating. It's okay.

The adhesive layer contained in the hollow part of the tube body can maintain this flattened state when the tube body is flattened together with the adhesive layer, and when heated, it becomes a foam and the tube body is replaced with the original tube. It can be restored and transformed into a shape.

In order to provide this adhesive layer in the hollow part of the tube body, a foamable resin composition, that is, one that has the property of foaming when heated above the decomposition temperature of the foaming agent contained therein, is used as shown in Figure 1. Alternatively, the foamable resin composition described above may be laminated in a tube shape on the inner peripheral surface of the tube body 1 to form the adhesive layer 2, or the above foamable resin composition may be formed into a sheet shape and this may be laminated onto the tube body 1 as shown in FIG. It may be inserted to form the adhesive layer 2.

In addition, 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 it is a resilient foam that can be restored to the original foam by heating. As shown in Figure 2, the flattened product is attached to the tube body 1.
It may be inserted into the adhesive layer 2.

After the adhesive layer is provided in the hollow part of the tube body as described above, the tube body is radially pressed and formed into a flattened product. This method may be any method such as pressing by press molding under temperature conditions that do not cause the adhesive layer to form a foam, or passing it between heated rolls. When the adhesive layer is made of a foamable resin composition, the tube main body and the adhesive layer are fused together by pressing while heating in this way.
Alternatively, fusion between this and the adhesive layer occurs, resulting in a flattened product. Further, when the above-mentioned adhesive layer is a flattened resilient foam, the adhesive contained therein acts as a hot melt adhesive to form a flattened product. However, during this crimping,
If the tube body is compressed excessively in the radial direction, it may undergo restoring deformation due to heating, so care must be taken.

In addition, if necessary, a sheet or tube made of the above-mentioned foamable resin composition or a flattened resilient foam and a hot melt resin layer may be laminated and used as an adhesive layer. The flattened state may be maintained.

The above-mentioned foamable resin composition includes a thermoplastic resin, a thermosetting resin, or a mixture thereof, a foaming agent, and, if necessary, a foaming aid, a curing agent, a curing accelerator, a crosslinking agent, a crosslinking aid, a filler, and a coloring agent. This foamable resin composition is prepared by blending additives, stabilizers, etc., and kneading this mixture using a mixing roll, etc., and the foamable resin composition is prepared under temperature conditions where the foaming agent does not decompose, or when the resin component is a thermosetting resin. If the resin is not hardened, it may be made into a sheet by extrusion molding under conditions where the resin does not harden, or it may be made into a foamable resin sheet.
Further, when forming the tube body, the material may be laminated in a tube shape on the inner circumferential surface of the tube body by two-layer extrusion molding.

Examples of the above-mentioned thermoplastic resin include polyethylene, ethylene-vinyl acetate copolymer, adhesive polyolefin, etc., and examples of the thermosetting resin include epoxy resin, and these may be blended if necessary. The blowing agent is regulated by the softening temperature and molding temperature of the resin, but azo compounds, nitroso compounds, hydrazide compounds, etc. are widely used.

The thickness of the above-mentioned foamable resin sheet is usually about 0.05 to 2M, and in the case of a foamable resin tube, the thickness is usually about 0.2 to 5mm.

In addition, it is preferable that the expansion ratio after heating is 2 to 30 times in practical terms.

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

The above-mentioned elastic foam means that when the foam itself is compressed and deformed by an external force, no external force is applied to it, regardless of whether the polymer material itself that forms the foam has elasticity. It is sufficient that the condition can be recovered to the above condition.

As for the foamed state of the elastic foam, an open cell type is preferable because it allows the adhesion agent to be contained in the voids and is easy to flatten, but the adhesion agent should be included to the extent that the flattened state can be maintained. If possible, closed cells may be present in some portions.

The apparent density of this foam is usually 0.5 or less, with a lower limit of about 0.005 and a more preferable range of 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. Also, if it is too low, the mechanical properties of the foam will deteriorate, 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 vine resin that softens or melts when heated and solidifies when cooled. This fixing agent is
It is necessary that its melting point or softening point is lower than that of the foam, generally 1 below room temperature.
It is preferable that the temperature is higher than 0°C.

As this fixing agent, various resins can be used as long as they have the above-mentioned melting point or softening point. Examples of resins that can be used as the adhesive include thermosetting resins such as epoxy resins, phenol resins, and polyester resins, and thermoplastic resins such as polyethylene, polypropylene, polyamide, and polybutyral. 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 resilient foam flattened product obtained using the above-mentioned elastic foam and fixing agent usually has a thickness of about 0.1 to 3 mm, and can be restored to a foam with a thickness of about 3 to 30 mm by heating. Good.

The reinforcing adhesive sheet of the present invention is obtained by pressing the flattened product obtained from the tube body and the adhesive layer as described above onto a sheet-like prepreg made of the thermosetting resin composition. Further, in the reinforcing adhesive sheet of the present invention, a protective film may be attached to the surface of the prepreg opposite to the surface to which the flattened material is attached. 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 above-mentioned 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 part of the sleeve/reinforcing layer after being heated and cured, it is expected that this will improve the reinforcing effect; Since the fiber-reinforced resin layer is provided so as to cover the entire surface, it gives good results to the moisture resistance of the layer 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 from polymer materials with excellent strength, moisture resistance, heat resistance, etc.
．． Between 0'01 and 0.5, preferably O,.

A molded material having a thickness of approximately 0.03 to 0.1 ttrm is used. Particularly suitable polymer materials are:
Although it is a polyester film, other films such as polyethylene film, nylon film, polyvinyl chloride film,
Various films such as polypropylene film can be applied.

The preferred properties of the adhesive sheet of the present invention obtained in this way are such that the prepreg does not substantially flow at room temperature and has self-retention properties, but is in a highly viscous state as a whole. be.

This material has flexibility and softness, and has a resistance of 250 to 300
The sheet does not show any damage even after being folded many times, and has the ability to be restored to its original state. Therefore, according to this preferred embodiment, since it has shape adaptability, it can be attached even if the material to be reinforced (metal plate) is wavy, mountain-shaped, square, curved, etc., and it is suitable for use as a reinforcing sheet. Can be applied effectively.

FIG. 3 shows an example of the reinforcing adhesive sheet of the present invention in a state where this sheet is attached to the outer panel of an automobile, and shows a sheet-like thermosetting resin prepreg 4 in which a reinforcing material 5 is embedded, A reinforcing adhesive comprising a flattened material 3 having a narrower width than the prepreg 4 in which a tube body 1 and an adhesive layer 2 are integrally flattened, and the flattened material 3 is attached to one side of the prepreg 4. The sheet is an automobile exterior panel 6
It is pasted and attached to the back surface 6a of.

By heating the reinforcing adhesive sheet after installation as shown in FIG. The thermosetting resin prepreg 4, whose viscosity had initially decreased, is pushed up to form a bead-shaped bulge 7, and as heating progresses over time, the prepreg 4
hardens.

FIG. 5 shows another example of the reinforcing adhesive sheet of the present invention installed, and shows the thermosetting resin prepreg 4.
However, the reinforcing material 5 was embedded, and the resin composition was such that the tensile modulus after heat curing was necessary and sufficient to improve the rigidity of the metal plate, and the glass transition temperature after heat curing was high. The first thermosetting resin composition layer 4a and the second thermosetting resin composition layer have a resin composition which has a tensile modulus insufficient to improve the rigidity of the metal plate and has a low glass transition temperature. The structure is the same as that shown in FIG. 3, except that it is composed of a thermosetting resin composition layer 4b.

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,
It can be widely applied to metal plates that are generally thin, such as home appliances such as televisions.

The reinforcing method using the reinforcing adhesive sheet of this invention is as follows:
In the case of a metal plate such as the one described above, such as a car body steel plate, the adhesive sheet is crimped onto the back side of the steel plate, and then a conventional heating method such as a hot air circulation heating furnace, an infrared heating furnace, a high frequency induction heating furnace, etc. is used. This can be achieved by heating the adhesive layer to form a foam, and in some cases, curing the prepreg. 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, by simply using the reinforcing adhesive sheet of the present invention, pressing it onto the object to be reinforced, and heat-treating it, a great reinforcing effect can be obtained, and the construction is extremely easy. This brings about effects such as convenience.

Next, examples of this invention will be described. In the following, the term ``bu'' refers to the ``junior'' section.

Example 1 50 parts of Epicoat #8.28 (bisphenol A type liquid epoxy resin manufactured by Yuka Shell Co., Ltd.), Epomic R-15
1 (Flexible epoxy resin manufactured by Mitsui Petrochemical Epoxy Co., Ltd.)
An epoxy resin composition consisting of 10 parts of Vylon #500 (polyester resin manufactured by Toyobo Co., Ltd.), 2 parts of dicyandiamide (an epoxy resin latent curing agent manufactured by Nippon Carbide Co., Ltd.), 50 parts of talc, and 2 parts of asbestos powder was mixed in a normal manner. The resulting resin mass was kneaded with rolls and formed into a sheet with a thickness of 1 mm using a direct pressure press, and glass cloth (WF-22D manufactured by Nittobo Co., Ltd.
104) was laminated to obtain a thermosetting resin prepreg.

On the other hand, 100 parts of ethylene-vinyl acetate copolymer (manufactured by Mitsui Polychemical Co., Ltd., Evaflex P-1407), 10 parts of a blowing agent (manufactured by Hydraulic Chemical Co., Ltd., Vinyhole DW-6), and a crosslinking agent (dicumyl peroxide) After kneading 1 part with a mixing roll, pelletizing with a pelletizer, and using an extrusion molding machine under conditions that the blowing agent does not decompose (extrusion die temperature 110°C), a foamable resin sheet (A) with a thickness of 1.4 m is made. ) was obtained.

In addition, polyethylene resin (Sumikisen L manufactured by Sumitomo Chemical Co., Ltd.)
-705) was formed into a tube using an extruder, and the outer diameter was 1
A polyethylene tube body with 0 resistance and a wall thickness of 0.8 fl was obtained.

After inserting the above-mentioned foamable resin sheet (A) cut into a width of 8 fl into this polyethylene tube body, the polyethylene tube body is compressed from the radial direction through a heated roll at about 80°C. A flattened resin sheet was obtained which acted as a hot melt adhesive. , and laminated to obtain a reinforcing adhesive sheet of the present invention.

This reinforcing adhesive sheet was pressure-bonded to a 0.8B thick steel plate so that the glass cloth of the prepreg was on the outside. After this pressure bonding, it was heated in an atmosphere of 140° C. for 30 minutes. As a result, the foamable resin sheet (A) was melted and foamed, and due to this foaming, the polyethylene tube body was restored and deformed into a tube shape, and the thermosetting resin prepreg was hardened into a convex shape along the tube-shaped body. .

When the steel plate reinforced in this way was used as a test piece and a ring strength test was conducted using the method shown below, the maximum bending stress was 5.
It was found that a very excellent reinforcing effect was obtained, whereas the maximum bending stress of the steel plate alone was 9 kg and 150 mm width.

Strength test> Two vertical flat plates (with a width of 5 mm) and whose tips have an inverted U-shaped cross section with a radius of curvature of 5 mm, placed in parallel with a distance of 100 mm between the tips.
A test piece with a width of 50 sag is supported horizontally on a support stand with a curvature radius of 5 fl from the top at the center.
The maximum bending stress (Ky/50 cod width) was measured when a load was applied to a vertical flat plate (width 50 m+) exhibiting a U-shaped cross section.

Example 2 Epicoat #82B (bisphenol A type liquid epoxy resin manufactured by Yuka Shell Co., Ltd.) 50 parts, Epicoat #1002
(bisphenol A type solid epoxy resin manufactured by Yuka Shell Co., Ltd.) 35 parts, Vylon #500 (polyester resin manufactured by Toyobo Co., Ltd.) 15 parts, Curesol 2MZ-AZINE (
An epoxy resin composition consisting of 5 parts of dicyandiamide (latent curing agent for epoxy resin manufactured by Shikoku Kasei Co., Ltd.), 5 parts of dicyandiamide (latent hardening agent for epoxy resin manufactured by Nippon Carbide Co., Ltd.), 50 parts of talc, and 2 parts of asbestos powder was placed on a regular mixing roll. The resulting resin mass was kneaded with a direct pressure press to a thickness of 0.
51I#I into a sheet shape, and then coated with glass cloth (
WE-22D-104) manufactured by Nittobo Co., Ltd. was laminated to form an uncured first thermosetting resin composition layer.

Next, 80 parts of Epicort #871 (dimer acid-modified epoxy resin manufactured by Yuka Shell Co., Ltd.), Epicort #1002
(Previously) 10 copies and Hiker CTBN1300X8
(BF, nitrile rubber manufactured by Gutdrich) were melt-mixed in a mixing pot, and 100 parts of the resulting composition was added with 5 parts of Cure Sea #2MZ-AZ I NE (mentioned above), 5 parts of dicyandiamide, and 50 parts of talc. part and asbestos powder 2
After mixing the ingredients and kneading them using a regular mixing roll, this is formed into a sheet using a direct pressure press to form a sheet with a thickness of 0.
．． A second thermosetting resin composition layer in an uncured state consisting of 8 baits was obtained. By bonding this to the first thermosetting resin composition layer, a thermosetting resin prepreg was obtained. The tensile modulus of the first and second thermosetting resin composition layers after heat curing was 95 Kg/mJ for the first layer and 3.0 Kg/- for the second layer. However, the heat curing conditions are 150° C. and 60 minutes. Further, the glass transition temperature of each layer was 141°C for the first layer and 39°C for the second layer.

On the other hand, polyethylene resin (manufactured by Sumitomo Chemical Co., Ltd., Sumirikisen L)
-705) 70 parts, ethylene vinyl acetate copolymer (manufactured by Mitsui Polychemical Co., Ltd., Evaflex P-2807) 30
Part, blowing agent (manufactured by Hydraulic Chemical Co., Ltd., Neocellvon P#1000
) and 1 part of a crosslinking agent (dicumyl peroxide) were kneaded using a mixing roll and then pelletized using a pelletizer to obtain a foamable resin composition (6).

Polyethylene resin (mentioned above) and the above foamable resin composition (
B) was formed into a tube using a two-layer extrusion molding machine with the polyethylene side facing outward, and the outer diameter was 10 parts m, the wall thickness was 0.7 was for the polyethylene resin layer, and the foamable resin composition (B) A tubular body with a layer thickness of 0.3 m was obtained.

Next, this tubular body is passed through a hot roll at about 80°C to press the two-layered tubular body together from the radial direction, so that the foamable resin composition (B) acts as an adhesive. A flattened product was obtained. This flattened product was pressed onto the second thermosetting resin composition layer side of the two-layer thermosetting resin prepreg cut into a 50 mm width to obtain a reinforcing adhesive sheet.

Next, this adhesive sheet was prepared in the same manner as in Example 1, and
．． After the second thermosetting resin composition layer side was pressure-bonded to a steel plate having a thickness of 8 tutz, it was heated at 140° C. for 30 minutes to foam and harden. When we conducted a strength test on the reinforcement thus obtained, it was 42Kg, 150s+s+width.
It was found that a very good reinforcing effect was obtained. Furthermore, when the steel plate was visually observed for sink marks, no sink marks were observed and the appearance was good.

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, manufactured by Nippon Rilsan Co., Ltd.) was applied to the entire void space of the foam. Bratamide H-103, melting point 80~
90°C) in an amount of 150y/nf, the foam was heated to 150°C and immediately thereafter flattened through cooling rolls.1. A flattened resilient foam with Osu+ thickness was obtained.

This flattened resilient foam was cut into 8H width and inserted into the polyethylene tube body obtained in Example 1.
By pressing the polyethylene tube body from the radial direction through a heated roll at about 80° C., a flattened product in which the polyamide powder served as a hot melt adhesive was obtained.

Using this flattened product, a reinforcing adhesive sheet of the present invention was obtained in the same manner as in Example 1, and this adhesive sheet was crimped onto a 0.8 mm thick steel plate in the same manner as in Example 1. The flattened foam was heated at 140° C. for 30 minutes to form a foam and to cure the prepreg. When the strength of the reinforcement thus obtained was tested, it was found to be 52Kf.
It was found that a very good reinforcing effect was obtained with a width of 1750 mtn. Further, the steel plate was visually observed for sink marks, but no sink marks were observed and the appearance was good.

Example 4 A polyester film (Lumirror #9 manufactured by Toshisha Co., Ltd.) was laminated as a protective film on the opposite side of the glass cloth from the laminate side of the thermosetting resin prepreg obtained in Example 1, and further Example 1 The flattened product obtained in above is used as the adhesive side of the polyester film in the above prepreg! The reinforcing adhesive sheet of the present invention was obtained by pressing on the opposite side.

Next, this adhesive sheet was pressure-bonded to a 0.8-thick steel plate so that the polyester film was on the outside.

This crimping work was carried out while unwinding the reinforcing adhesive sheet, which was made into a tape-like roll, and the crimping work was very good, with no interlayer adhesion or resin adhesion due to the polyester film. Met. This pressed product was heated at 140°C for 30 minutes to foam and harden.
It was possible to mold a reinforcing layer having a polyester film that adhered well to the convex portion of the thermosetting resin, and the polyester on the outer surface provided excellent appearance, moisture resistance, abrasion resistance, etc.

[Brief explanation of drawings]

1 and 2 are sectional views showing two examples of tube bodies containing an adhesive layer in the hollow portion for obtaining a flattened product in the reinforcing adhesive sheet of the present invention, and FIG. 3 is a reinforcing adhesive sheet of the present invention. FIG. 4 is a cross-sectional view showing an example of the adhesive sheet for use in the present invention before heating, FIG. 4 is a cross-sectional view showing the adhesive sheet in FIG. 3 after heating, and FIG. FIG. 7 is a cross-sectional view showing another example of the reinforcing adhesive sheet in a state in which it is installed before heating. DESCRIPTION OF SYMBOLS 1... Tube main body, 2... Adhesive layer, 3... Flattened material, 4... Thermosetting resin prepreg, 5... Reinforcement material. Patent applicant Nissan Motor Co., Ltd. (1 other person) Figure 1 @
Continuation of Figure 2, page 1

Claims (1)

[Scope of Claims] fl) A sheet-like thermosetting resin prepreg in which a reinforcing material is embedded, and a flattened article attached to one side of the prepreg and whose width is narrower than that of the prepreg, and this flattened article has the following properties: The tube main body, which includes an adhesive layer in the hollow part, is flattened together with the adhesive layer, and this flattened state is maintained by the adhesive layer, and the adhesive layer becomes a foam when heated, and also covers the tube body. A reinforcing adhesive sheet featuring scales that can be restored and deformed into a tube shape. (2) The reinforcing adhesive sheet according to claim 1, wherein the tube body can be deformed substantially back to its original tube shape by heating.