JP2812789B2 - Resin adhesive sheet for thin plate reinforcement - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin adhesive sheet for reinforcing a thin plate such as a metal plate.

[Conventional technology]

Generally, metal plates used for automobile bodies and doors,
For example, steel plates have a thickness
A steel sheet of about 0.6 to 0.8 mm is used. An inner plate such as a metal reinforcing member is attached to such a steel plate by spot welding or the like from the viewpoint of improving the strength of the vehicle body. But,
In this case, the weight of the metal reinforcing member itself increases due to the weight of the metal reinforcing member itself. Therefore, the applicant of the present application has applied a thermosetting resin such as an epoxy resin, an acrylic resin, or a phenol resin as a main component instead of the metal reinforcing member, adhered a reinforcing base material such as a glass cloth, and provided a large number of through-holes. A thermosetting resin sheet having holes formed therein has been proposed (JP-A-59-53573, JP-A-59-54550). The large number of through-holes provided in the sheet have a function of releasing air accumulated between the steel sheet and the sheet when the sheet is attached to the steel sheet. Since this type of sheet is lighter than the metal reinforcing member, the weight of an automobile or the like can be reduced. Further, since a large number of through holes formed in the sheet can prevent the generation of air pockets, a sufficient bonding area can be secured. However, when reinforced by a sheet having a large number of through holes as described above, particularly in a part of an automobile or the like which is strongly affected by rainwater or the like, rainwater or the like penetrates from the through holes and generates rust on the steel sheet. In addition, the reinforcing effect of the sheet itself is slightly inferior due to the presence of the large number of through holes.

[Problems to be solved by the invention]

On the other hand, a thermosetting resin such as an epoxy resin as a main component,
A glass cloth (having increased rigidity by impregnation and curing of a heat-resistant resin) was adhered as a reinforcing substrate to an uncured layer (prepreg) of a thermosetting resin composition containing a reinforcing material such as glass powder. Adhesive sheets have also been proposed. As shown in FIG. 13, such a sheet is temporarily fixed by using the uncured layer (prepreg) 11 on the inside of an automobile door steel sheet 10 with its adhesiveness or the like down, and is used for baking paint of a vehicle body. When the uncured layer 11 is thermally cured by using the applied heat, the uncured layer 11 is permanently fixed inside the door steel plate 10. In FIG. 13, 12 is a glass cloth, 13 is a window glass, and 14 is a lining material. In this adhesive sheet, the glass cloth 12 has rigidity, and the rigidity of the adhesive sheet as a whole forms a single plate-like shape, and is not in a flexible state. Absent. However, when reinforcing the door steel sheet 10 in this way, when the area of the adhesive sheet increases, for example, when the area becomes 10 cm × 30 cm or more,
When the temperature is returned to room temperature by cooling after the completion of heating, the cured layer formed by the thermal curing of the uncured layer 11 has a cooling shrinkage caused by a difference in linear expansion coefficient between the glass cloth 12 (the reinforcing base material layer) and the cured layer. Due to the difference in stress, strain stress is generated, and the stress concentrates in the central portion, and as shown in FIG.
And a local swelling 16 is generated in the glass cloth 12 (reinforcement base material layer) at the crack generation portion. When such defects occur, not only is the reinforcing effect as designed not obtained, but also
Since swelling occurs locally, the aesthetic appearance is impaired at portions visible to the naked eye, such as the backside of the bonnet or the trunk, regardless of where it is difficult to see from the outside, such as inside a door steel plate.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a thin-plate reinforcing resin adhesive sheet that does not reduce the reinforcing effect based on the occurrence of cracks or the like and does not adversely affect the thin plate to be reinforced by rainwater infiltration or the like.

[Means for solving the problem]

In order to achieve the above object, a resin adhesive sheet for reinforcing a thin plate according to the present invention has an uncured layer of a thermosetting resin composition having an adhesive surface on one side and serving as an adhesive surface for a thin plate, and the thermosetting resin composition. A reinforcing base material layer which is formed in close contact with the other side of the uncured layer, and the reinforcing base material layer has a cut depth exceeding the thickness of the thermosetting resin composition uncured layer. The configuration is such that a number of cuts reaching the front are distributed and formed.

[Action]

The thin-plate reinforcing resin adhesive sheet of the present invention is temporarily fixed (temporarily bonded) to a thin plate such as a steel plate by utilizing the adhesiveness on one surface side of a thermosetting resin composition uncured layer (including a semi-cured layer). . Then, by heating in this state, the thermosetting resin composition uncured layer is heat-cured and firmly adheres to the thin plate for reinforcement. At that time, the notch depth, through a number of cuts formed in the state of reaching the thermosetting resin cured layer through the reinforcing base layer, after heating and curing, absorbs the strain stress generated during cooling, the center The stress concentration in the part is avoided. Therefore, a large crack does not occur in the cured layer. Further, since the cut does not penetrate to the adhesive surface of the hardened layer, the strength of the cut hardly decreases due to the formation of the cut, and the surface of a thin plate such as a steel plate is immersed by rainwater or the like. It is not done.

 Next, the present invention will be described in detail.

The resin adhesive sheet for reinforcing a thin plate of the present invention (hereinafter abbreviated as “adhesive sheet”) is obtained using an uncured thermosetting resin composition layer and a reinforcing base material layer.

The above-mentioned thermosetting resin composition uncured layer (hereinafter referred to as “uncured layer”)
Abbreviated) is an epoxy resin,
A thermosetting resin such as an acrylic resin, a phenol resin, a polyester resin, a melamine resin, and a urea resin is used alone or in combination, and it is particularly preferable to use an epoxy resin. As such an epoxy resin, various epoxy resins such as glycidyl ether type, glycidyl ester type, glycidylamine type, linear aliphatic epoxide type, and alicyclic epoxide type or modified epoxy resins thereof are used. Used alone or in combination depending on the properties of In the uncured layer, a heat-activated curing agent is usually blended as a curing agent for the thermosetting resin. Such a curing agent may be an ordinary curing agent that exerts a curing action by heating, and generally only needs to be active in a temperature range of 80 to 200 ° C. For example, as the main curing agent for the epoxy resin, dicyandiamide, 4,4'-diaminodiphenylsulfone, phenol, various acids or acid anhydrides, polyamidoamine and the like can be mentioned. Also,
Examples of the curing accelerator include imidazole derivatives such as 2-n-heptadecyl imidazole, isophthalic acid or adipic dihydrazide, guanidines, and N, N-dialkylthiourea derivatives. The amount of such a curing agent used is usually 3 to 30 parts for the main curing agent and 100 parts by weight for the epoxy resin (hereinafter abbreviated as "parts"), and
Set to 10 parts or less.

In the uncured layer, in addition to the thermosetting resin and the curing agent, the thermosetting resin composition itself has a cohesive strength to the extent that a sheet can be formed, and also has a melt viscosity to prevent dripping or to prevent dripping. Various additives are used as needed for the purpose of lowering and improving wettability.

For example, in order to improve sheet forming ability, polyvinyl butyral, polyamide, polyamide derivative, polyester, polysulfone, polyketone, bisphenol A
And a thermoplastic resin such as a high molecular weight epoxy resin derived from epichlorohydrin is used as a sheet forming agent. In addition, liquid isoprene rubber, butadiene-acrylonitrile copolymer or a derivative thereof is also used for the above purpose. These amounts are usually used in the thermosetting resin 10
It is set to about 5 to 100 parts for 0 part.

In addition, various fillers such as calcium carbonate, talc, silica, alumina, titanium oxide and the like can be used in the thermosetting resin composition.

At this time, the addition amount of the filler is, when using the thermosetting resin composition blended with this filler to produce the adhesive sheet of the present invention, and when it is used for reinforcing the door outer panel, etc., after heat curing It is usually preferable to set the amount to not more than 150 parts with respect to 100 parts of the resin component to the extent that the adhesive strength to the outer plate or the like is not impaired.

Further, reactive diluents such as butyl glycidyl ether and monoglycidyl ether of long-chain alcohol, and phthalic acid-based plasticizers such as dioctyl phthalate are used for the purpose of lowering the melt viscosity of the composition and improving wettability. Used as an anti-oxidant. The amount of these used is usually set to about 5 to 30 parts per 100 parts of the thermosetting resin.

In addition, in addition to the above additives, the uncured layer is decomposed and foamed at the time of heat curing of the uncured layer for the purpose of increasing the reinforcing effect by increasing the thickness of the uncured layer after heat curing of the uncured layer. Short fibers for suppressing a decrease in strength of a foaming agent and a cured layer after foaming (formed by curing of an uncured layer) and a thixotropic agent for finely uniforming foamed bubbles by the foaming agent are required. Used accordingly. That is, the stiffness is said to be proportional to the cube of the thickness. Therefore, the reinforcing effect of the stiffness can be obtained by increasing the thickness of the uncured layer by foaming a foaming agent. Thus, the effect of further improving the reinforcing effect on a thin plate such as a steel plate can be obtained.

As the foaming agent, azo compounds such as azodicarbonamide, azobisisobutyronitrile and the like, nitroso compounds such as dinitrosopentamethylenetetramine,
Hydrazide compounds such as paratoluenesulfonyl hydrazide and 4,4'-oxybenzenesulfonyl hydrazide are used, and they are used alone or in combination. The amount of the foaming agent is usually set to 0.5 to 10 parts based on 100 parts of the thermosetting resin. If the amount of the foaming agent is less than the above range, the reinforcing effect due to the thickness reinforcement cannot be obtained much.On the contrary, if the amount exceeds the above range, the foaming agent becomes excessively foamed and the reinforcing effect due to the thickness reinforcement is reduced. It is. The decomposition temperature of such a foaming agent is usually set to 100 ° C. or higher so that foaming occurs when the uncured layer is cured by heating and does not foam during other storage.

A foaming aid may be used together with the foaming agent, if necessary. Examples of this type of foaming aid include zinc white inorganic substances,
Examples include metal soaps such as zinc stearate and urea compounds. The amount of the foaming aid is usually in the range of 0.2 to 7 parts based on 100 parts of the thermosetting resin.

As described above, it is usually preferable to set the expansion ratio to 1.3 to 5 times by using a foaming agent (including a foaming aid).

Short fibers added for the purpose of suppressing a decrease in resin strength due to the resin foaming include inorganic short fibers such as glass fibers, organic short fibers such as vinylon and nylon, and the like.
Short metal fibers such as silver and stainless steel may be used, and may be used alone or in combination. In particular, as the short fibers, those having an aspect ratio (length / diameter) of 5 to 350 and a diameter of 1 to 30 μm are preferable from the viewpoint of dispersibility and the effect of preventing a reduction in resin strength. The use amount of such a short fiber is preferably set in the range of 10 to 100 parts with respect to 100 parts of the thermosetting resin, and when the use amount is less than the above range, the effect of preventing the resin strength from lowering. Not enough,
Conversely, if it exceeds, it tends to be difficult to achieve uniform dispersion in the uncured layer.

Furthermore, the addition of the thixotropy-imparting agent causes the foamed cells of the resin by the foaming agent to be in a fine and uniform foaming state, whereby the resin strength and the resin thickness after foaming become uniform. In addition, the adhesive sheet of the present invention includes a vertical portion or a lower surface of the adherend as a portion to which the adhesive sheet is attached. In this case, since the adhesive sheet is attached upside down, the fluidity of the resin during curing is suppressed. The adhesive sheet must be prevented from slipping and falling off. In order to prevent such displacement and drop-off, it is necessary to add a thixotropic agent.

Examples of the thixotropy-imparting agent include aerosil and asbestos fiber, and among them, organic bentonite is preferable in terms of effect. The amount of such a thixotropic agent used is preferably set in the range of 3 to 30 parts with respect to 100 parts of the thermosetting resin from the viewpoint of the effect.

The short fiber or thixotropic agent can be used independently without using it together with the foaming agent. That is, the short fiber exerts the reinforcing effect of the uncured layer by its independent action, and the thixotropy-imparting agent, when the adhesive sheet of the present invention is temporarily fixed to a steel plate or the like, the uncured layer of the adhesive sheet is too soft. It has the effect of preventing the sagging position from shifting.

Examples of the reinforcing base material of the reinforcing base material layer formed in close contact with the other surface of the uncured layer include organic and inorganic woven fabrics, nonwoven fabrics and knitted fabrics. Among such woven fabrics, non-woven fabrics and knits (hereinafter collectively referred to as "cloth materials"), glass cloth is preferable. In some cases, metallic reinforcements are also used. The thickness of the reinforcing base material layer composed of such a material is usually set to about 5 to 500 μm. The cloth material for the reinforcing base material is usually used by impregnating and curing a heat-resistant resin (filling treatment) to impart necessary rigidity to the reinforcing material layer. The heat-resistant resin needs to withstand heating when the uncured layer is cured by heating, and thermosetting resins such as phenol resin, epoxy resin, melamine resin, and acrylic resin are used alone or in combination. . This heat resistant resin is usually used at a basis weight of ² to 30 g / m ² with respect to the above-mentioned cloth material. The heat-resistant resin is usually used in combination with a curing agent and, in some cases, a curing accelerator. The reinforcing base material layer made of the cloth material treated with the heat-resistant resin in this way has rigidity and acts as a reinforcing layer. Further, since the cloth material is impregnated and cured with the heat-resistant resin, when the adhesive sheet of the present invention is cut and used, the cloth material is prevented from fraying. As described above, a cloth material that is not treated with a heat-resistant resin and has no rigidity has poor sticking workability or cutability of the cloth material.

The adhesive sheet of the present invention includes the uncured layer and the reinforcing base material layer, and is temporarily fixed to a thin plate such as a steel plate by utilizing the adhesiveness on one surface side of the uncured layer, and thereafter, the uncured layer is heated. The layer is hardened by heating and is permanently fixed (finally bonded). Usually, the uncured layer is entirely tacky, so that one side is an adhesive face. However, in some cases, the uncured layer itself lacks tackiness or the tackiness alone is insufficient. In such a case, an adhesive resin layer may be further formed on one surface side of the uncured layer. As described above, the mode of forming the adhesive on one side of the uncured layer is based on the case where the adhesive property of the thermosetting resin composition itself forming the uncured layer is used, and the method of forming the adhesive resin layer and bonding the adhesive. There are two modes utilizing the adhesiveness of the resin layer. In the latter case,
The adhesive resin layer itself constitutes a part of the uncured layer.

As the adhesive resin for forming the adhesive resin layer, the same thermosetting resin as used for forming the uncured layer, particularly an epoxy resin, is used. Molding agents, anti-sagging agents and wetting improvers are used in the same proportions as described above, if necessary. For example, the degree of formation of the B-stage is adjusted so that the adhesive resin layer independently exhibits tackiness.

As described above, the adhesive sheet of the present invention is temporarily fixed to a thin plate such as a steel plate by using the adhesiveness on one surface side of the uncured layer. Is impaired. Therefore, a magnetic powder such as a ferrite powder may be mixed into the uncured layer, and the uncured layer may be temporarily fixed using the magnetic force. That is, when the outside air temperature decreases in winter or the like, the tackiness decreases and temporary fixing becomes difficult. In particular, the above effect is strong in steel plates whose surfaces are stained with oil, etc.
As an improvement, magnetizing is performed. In addition, if the uncured layer is made to have a weak tackiness and the shortage is compensated for by the magnetic force, a repositioning operation can be performed even when a temporary displacement is required and repositioning is required. It will be easier. Examples of the magnetic powder include rare earth cobalt magnet powder and alnico magnet powder in addition to the ferrite powder (for example, barium or strontium ferrite powder).
Used alone or in combination. The mixing amount of such a magnet powder is usually 100 to 40 parts per 100 parts of the thermosetting resin.
0 parts, preferably 150 to 250 parts. Mixing the magnetic powder in this way increases the density of the uncured layer and increases the product weight per unit area, but eliminates the above-mentioned adverse effects by including a foaming agent in the uncured layer and foaming the resin during heat curing. be able to.

It is preferable that the total amount of the various additives is set in the range of 100 to 300 parts with respect to 100 parts of the thermosetting resin.

The adhesive sheet of the present invention is characterized in that a number of cuts are formed in a reinforcing base material layer which is formed in close contact with the other surface of the uncured layer, and the cut depth of the uncured layer is greater than that of the uncured layer. The distribution is formed so as to reach just before the surface, which is the most significant feature. Specifically, the cut depth is
The thickness of the sheet is preferably 30% or more, and less than 100%.
Particularly preferably, it is 60 to 95%. The cut shape may be a perforated shape or a slit shape, and may be a triangular shape, a pentagonal shape, an elliptical shape, or the like.
Further, the area of the opening of the cut is preferably set to 0.7 mm ² or less from the viewpoint of preventing cooling shrinkage distortion of the hardened layer while preventing infiltration of rainwater or the like. Generally, when the cut is a perforation, the diameter of the cut is set to 1 mm or less,
Preferably 0.3 to 0.9 mm, if the slit is a slit, the slit length is 4 to 20 mm and the slit width is 0.2 to 0.9 mm
Is set within the range. Preferably the slit length is 3 to
6mm, slit width is 0.3-0.6mm. Such cuts are set so that the relations l ₁ and l ₂ of the slits 1 are in the range of 10 to 80 mm, preferably in the range of 15 to 50 mm, as shown in FIG. . In the figure, 2
Is a reinforcing base material layer, and 3 is an uncured layer. The distribution density is set at a ratio of 5 to 100 pieces / 100 cm ² , preferably 10 to 100 pieces / 100 cm ^2.
30 pieces / 100 cm ² . This is the same even if the cut is a hole other than a slit. The slits may be formed in such a manner that the slits 1 are all aligned in the same direction as shown in FIG. 2, or may be vertically and horizontally orthogonal as shown in FIG. Further, as shown in FIG. 4, the perforation 1 and the slit 1 may be combined. In these cases, the cut depth of the cut is formed so as to extend beyond the reinforcing base material layer 2 and reach just before the bonding surface of the uncured layer 3. Accordingly, the cut depth may be about half the thickness of the uncured layer 2 as shown in FIG.
There is no problem even if it approaches the adhesive surface side beyond that. 5 and 6, when the uncured layer 3 has an adhesive resin layer 4 on one surface side, the lower end of the cut may reach the adhesive resin layer 4, The layer 4 may be embedded in the layer 4. Also, the reinforcing material layer 2
As shown in FIGS. 7 and 8, when the uncured layer 3 is formed of a coarse cloth material, a cut (for example, perforation 1) is formed in the uncured layer 3 as shown in FIG. You may make it locate in. Therefore, in the present invention, forming a cut in the reinforcing material layer 2 also includes a mode in which a cut is formed in the uncured layer 3 and the cut is positioned in the cloth material as described above.

The adhesive sheet of the present invention can be manufactured, for example, as follows. That is, the above-mentioned raw materials are appropriately blended, kneaded using a mixing roll or the like, and the obtained resin mass is formed into a sheet by hot pressing or the like to form an uncured layer.

On the other hand, a cloth material is impregnated with a heat-resistant resin, which is thermally cured to form a sheet-like reinforcing substrate.

Next, the reinforcing sheet is laminated on the other side of the uncured layer to form an adhesive sheet. In this case, the thickness of the uncured layer is usually formed to be 0.4 to 3 mm, and the thickness of the reinforcing base material layer is set to be 0.05 to 0.3 mm. Then, the thickness of the entire sheet is usually set in the range of 0.6 to 3 mm from the viewpoint of the reinforcing effect and the like.

A cut, for example, a slit or a perforation, is formed on the adhesive sheet thus obtained from the reinforcing base material layer side with a cutting blade or the like.

The adhesive sheet of the present invention thus obtained is temporarily fixed to a predetermined place of a thin plate such as a steel plate by utilizing the adhesiveness on one surface side of the uncured layer, and heat-treated in that state to form the uncured layer. Heat and cure. In this case, when a foaming agent is contained in the uncured layer, the uncured layer foams when heated and cured, and the entire thickness increases. And the adhesive sheet of the present invention is formed by curing the uncured layer by heat curing.
Strongly fixed (finally fixed) to a thin plate such as a steel plate, and has a reinforcing effect. In this case, since a large number of cuts are formed in the adhesive sheet at the time of cooling and shrinking after heat curing,
Even if distortion occurs due to cooling shrinkage in the hardened layer, the distortion is absorbed by a large number of cuts and the stress concentration phenomenon does not occur. Therefore, unlike the related art, a phenomenon that a large crack is generated in the hardened layer and a swelling occurs in the reinforcing base material layer corresponding to the crack does not occur.

The adhesive sheet of the present invention is applicable not only to a steel plate such as an outer plate of an automobile but also to a generally thin metal plate such as a case of home appliances such as various vehicles, electric refrigerators and washing machines. And can be widely adapted.

〔The invention's effect〕

As described above, in the adhesive sheet of the present invention, a large number of cuts are formed in the reinforcing base material layer so that the cut depth exceeds the layer and reaches just before the bonding surface of the uncured layer. Therefore, the adhesive sheet is temporarily fixed to a thin plate, and then, at the stage where the uncured layer is cured by heating and then cooled, the cooling shrinkage strain generated in the cured layer is absorbed by a large number of cuts and the stress concentration phenomenon occurs. Does not occur. Therefore, as before,
No large cracks due to stress concentration occur. as a result,
The reduction of the reinforcing effect based on the crack and the local expansion of the reinforcing base material layer caused by the crack do not occur. Further, since the cut is not formed in a through-hole shape, rainwater does not reach the surface of a thin plate such as a steel plate through the cut and does not rust the steel plate surface. Further, since the cut is not in the shape of a through-hole, even if a large number of cuts are formed, the cured layer is in a continuous state at least on the adhesive surface side. Therefore, there is almost no decrease in strength due to the formation of cuts. In particular, when a foaming agent is contained in the uncured layer and foaming is performed when the uncured layer is heat-cured, the thickness of the resulting cured layer is significantly increased, and therefore the reinforcing effect is significantly improved. Will be able to

 Next, examples will be described together with comparative examples.

Example 1 45 parts of Epicoat # 871 (manufactured by Yuka Ciel, dimer acid-modified epoxy resin), 40 parts of Epicoat # 1002 (manufactured by Yuka Ciel, bisphenol A type epoxy resin) and 15 parts of liquid isoprene rubber were used. The mixture was dissolved and mixed in a mixing pot. And
To 100 parts of the obtained composition, 0.6 part of an imidazole-based curing agent (Cyuazole C ₁₁ Z) was further added, and dicyandiamide 5 was added.
, 50 parts of talc, 15 parts of organic bentonite as a thixotropic agent, and 3 parts of a neoservon P # 1000 (hydrazide-based) blowing agent, and kneaded with an ordinary mixing roll. The resin mass obtained in this way is hot pressed
It was formed into a 1.0 mm thick sheet. Next, a glass cloth (glass cloth impregnated and cured with a melamine resin, a glass cloth weight per unit area of 220 g / m ² , a melamine resin weight per unit area of 20 g / m ² ) was laminated to form an overall thickness of 1.2 mm. Then, as shown in FIG. 1, a slit having a width M of 0.4 mm and a length N of 5 mm was formed on this adhesive sheet with a cutting blade such that the slit intervals l ₁ and l ₂ were 25 mm each. . In this case, the depth of the slit was set to approximately the center in the thickness direction as shown in FIG.

[Examples 2 to 5] As shown in Table 1 below, an adhesive sheet was obtained in the same manner as in Example 1 except that the raw material composition and the cut shape were changed.

Example 6 A sheet having a thickness of 1.0 mm was formed in the same manner as in Example 1, and an adhesive resin layer having a composition having the following composition was formed on one surface of the sheet to a thickness of 0.3 mm.

Then, on the other side of the sheet, the same glass cloth as in Example 1 was similarly laminated to form an overall thickness of 1.5 mm. Next, as shown in FIGS. 5 and 6, a round hole having a diameter of 0.5 mm was formed on the adhesive sheet with a cutting blade so that the distances l ₁ and l ₂ were each 20 mm.

Example 7 In Example 1, when forming a sheet having a thickness of 1.0 mm, 180 parts of ferrite powder was added to the resin composition of Example 1 and blended. Otherwise in the same manner as in Example 1, a similar adhesive sheet was obtained. Then, it was magnetized by a magnetizer.

Comparative Example 1 A sheet made of the thermosetting resin composition was formed in the same manner as in Example 1, and an adhesive sheet was formed by laminating a glass cloth similar to that of Example 1 on the other side of the sheet.
In this case, no cut was formed by the cutting blade.

[Comparative Example 2] A sheet made of a thermosetting resin composition was formed in the same manner as in Example 2, and then a glass cloth which had not been impregnated and cured with a melamine resin was laminated in the same manner as in Example 1 to obtain a product. An adhesive sheet having a thickness of 1.2 mm was prepared, and through holes having a diameter of 5 mm were formed in the adhesive sheet at the same interval as the slit of Example 1.

Various characteristics tests were performed on the adhesive sheets obtained in the above Examples and Comparative Examples. The result is described in the second section below.
It is shown in the table. The various property tests were performed according to the following methods.

<Crack initiation test> A steel plate (dimensions: 200 x 600 x 0.6 mm) was used as a thin plate, and an adhesive sheet (dimensions: 180 x 500 x 1.2 mm) was temporarily fixed to the thin plate as shown by hatching in Fig. 9. In water at 20-25 ° C in the state
After immersion for 10 minutes, pull it up and drain it, then put it in a curing oven at 180 ° C for 30 minutes to heat and cure, then air-cooled at room temperature, then cut the adhesive sheet and visually inspected for internal cracks .

 ○: No crack.

 Δ: Slight cracks are observed.

 ×: cracks are observed.

<Bending strength test> A cold-rolled steel plate (dimensions: 150 x 80 x 0.8 mm) as a thin plate
The adhesive sheet (dimensions: 140 × 50 × 1.2 mm) was temporarily fixed thereto, placed in a curing oven at 180 ° C., cured, and then air-cooled at room temperature and subjected to a test. The test was carried out by supporting the steel sheet with the adhesive sheet at both ends with triangular prisms as shown in FIG. 10, applying a force of P to the center, and examining the amount of bending. In FIG. 10, a hatched portion indicates an adhesive sheet. In this case, the span 1 is 100 mm and the load speed V = 5
mm / min.

<Strain test of steel sheet> The adhesive sheet obtained in each of the examples and comparative examples has a thickness of 0.
After affixing to the surface of 8mm steel plate, in an atmosphere at a temperature of 180 ° C
Heat cured for 30 minutes. At the time of this heat curing, it was visually observed whether or not the steel sheet was distorted. Next, this was cooled to room temperature, and attention was paid to the surface of the steel sheet to check whether or not the steel sheet was distorted.

 …: No distortion.

 Δ: slight distortion is observed.

 X: Distortion is observed.

<Cutability> When the adhesive sheets obtained in Examples and Comparative Examples were cut using a cutter, the state of loosening of the reinforcing substrate on the cut surface was visually observed.

 …: No loosening of the reinforcing substrate.

 ×: There is loosening of the reinforcing substrate.

<Pasting workability> The adhesive sheets obtained in Examples and Comparative Examples were 70 mm wide,
The workability when attaching it to a steel plate with one hand was examined after finishing to a length of 300 mm.

 ○: Can be attached with one hand.

 ×: The product is bent and cannot be operated with one hand.

<Swelling test> After each adhesive sheet was temporarily fixed to a steel plate under the same conditions as in the above crack initiation test, heat-cured, and then air-cooled at room temperature, whether or not the reinforcing base material layer had swollen. Was visually observed.

 ○… No swelling.

 ×: Slight swelling is observed.

<Rust test> In the same manner as in the bending strength test, the adhesive sheet was temporarily fixed to produce a steel sheet. This test piece is electrodeposited and then
The adhesive sheet was placed in a curing oven at 180 ° C. and baked, and the adhesive sheet was cured by heating. This electrodeposition-coated product was used as a test piece and subjected to a salt water spray test for 500 hours using a salt water spray tester. Thereafter, the adhesive sheets obtained in Examples and Comparative Examples were peeled off, and the interface with the steel sheet was observed to evaluate the occurrence of rust.

 …: No rust occurred.

 Δ: Rust is slightly observed.

 ×: Rust is observed.

From the results shown in Table 2, it can be seen that the products of Examples have no cracks or swelling due to cooling shrinkage strain after heat curing, and have high strength. On the other hand, the product of Comparative Example 1 had cracks and swelling based on the cooling shrinkage strain, and the product of Comparative Example 2 had less such cracks and swelling, but it was difficult to form through holes. Therefore, it can be seen that characteristics such as strength are inferior to those of the example products. Further, rust was observed in the comparative examples, but no rust was observed in all of the examples.

[Brief description of the drawings]

1, 2, 3, 4, 5, 6, 7, and 8 each show the configuration of an embodiment of the present invention, and FIG. 9 shows a crack initiation test. Explanatory diagrams of FIGS. 10 and 11
The figure is an explanatory view of the bending test, FIG. 12 is a sectional view of the conventional example, and FIG.
The figure is a sectional view showing a reinforced state of an automobile door. DESCRIPTION OF SYMBOLS 1 ... Slit, 2 ... Reinforcement base material layer, 3 ... Uncured layer of thermosetting resin composition

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-124974 (JP, A) JP-A-59-54550 (JP, A) JP-A-2-80479 (JP, A) JP-A 63-124 199785 (JP, A) JP-A-50-5677 (JP, A) JP-A-58-65341 (JP, U) JP-A-2-14340 (JP, U) JP-A 52-16295 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) C09J 7/00-7/04

Claims (7)

(57) [Claims] 1. A thermosetting resin composition uncured layer having a tacky surface on one side and serving as an adhesive surface to a thin plate, and a reinforcing base formed in close contact with the other surface of the thermosetting resin composition uncured layer. Material layer, and the reinforcing base material layer has a number of cuts in which the cut depth reaches the bonding surface of the thermosetting resin composition uncured layer beyond the layer and is distributed and formed. Characteristic resin adhesive sheet for thin sheet reinforcement. 2. The thermosetting resin composition according to claim 1, wherein the uncured layer contains a foaming agent which is decomposed and foamed by heating, and foams when the uncured layer is cured by heating. Resin adhesive sheet for thin sheet reinforcement. 3. The resin adhesive sheet for reinforcing a thin plate according to claim 1, wherein the uncured layer of the thermosetting resin composition contains a magnetic powder. 4. The resin adhesive sheet for reinforcing a thin plate according to claim 1, wherein one side of the uncured layer of the thermosetting resin composition is formed on an adhesive resin layer. 5. The thermosetting resin composition uncured layer excluding the adhesive resin layer contains a foaming agent which is decomposed and foamed by heating, and foams when the uncured layer is heat-cured. Item 4. The thin-plate reinforcing resin adhesive sheet according to item 4). 6. The resin adhesive sheet for reinforcing a thin plate according to claim 1, wherein the cuts are in the shape of a hole or a slit. 7. The resin adhesive sheet for reinforcing a thin plate according to claim 1, wherein the area of the opening of the cut is 0.7 cm ² or less.