JPH08164591A - Reinforcing material - Google Patents

Abstract

PURPOSE: To provide a reinforcing material which has good initial adhesion, peelability from released paper, and sticking work efficiency in a wide temperature range. CONSTITUTION: In a reinforcing material, a thermosetting resin layer which is formed using an epoxy resin composition containing components (A)-(C) is laminated on a reinforcement base material. In the epoxy resin composition, the ratio between an isocyanate group (X) in the component (C) and a hydroxyl group (Y) in the component (A) is set up to be X/Y=0.25-1.0. The component (A) is a compatible mixture of an epoxy resin which is liquid at room temperature and a solid type epoxy resin with the dgree of polymerization of 4 or more; the component (B) is a curing agent; the component (C) is polyisocyanate.

Description

Detailed Description of the Invention

The present invention has an excellent reinforcing effect and a vibration damping effect, and also has excellent initial tackiness and release paper releasability from low temperatures to high temperatures throughout the four seasons.
The present invention relates to a reinforcing material which is a thin plate member used for reinforcing a thin plate such as a steel plate of a car body of an automobile, which has extremely good workability in sticking.

[0002]

2. Description of the Related Art Conventionally, for example, in automobiles and the like, steel plates of vehicle bodies have been reinforced in various ways. For example, the roof,
For outer panels with a relatively large area and a flat shape, such as fenders, hoods, trunks, quarter panels, and doors, but with a thin thickness, it is necessary to have appropriate rigidity against external force structurally. The method of attaching various reinforcing materials to the inside of the outer plate is adopted.

As the above-mentioned reinforcing base material, in recent years, various laminated type sheet-like reinforcing materials obtained by applying a thermosetting resin composition having an adhesive property at room temperature to the surface of a base material such as metal or glass cloth. Proposed.

[0004]

However, the reinforcing method using the above-mentioned laminated type sheet-like reinforcing material has the following problems. That is, in the case of a sheet-shaped reinforcing material, from the viewpoint of workability of sticking to an adherend (steel plate),
It is necessary that one side of the reinforcing material has adhesiveness at room temperature. However, when tackiness is imparted by a resin system mainly composed of a thermosetting resin, this tackiness greatly changes depending on temperature, and a resin type having good tackiness in the summer has a lower tackiness in the winter, etc. Problem occurs.

As a result, it is necessary to manufacture different reinforcing materials for summer and winter, respectively, which causes problems such as complicated material management, production management, and inventory management. In addition, when two types of reinforcing materials for summer and winter are produced, it becomes difficult to cope with abrupt temperature changes, for example, temperature changes during the daytime and nighttime, and improvement is strongly demanded in the automobile industry etc. Has been done.

By the way, in order to impart tackiness, it is possible to use an adhesive material such as an adhesive tape having a low temperature sensitivity, but in the case of the above-mentioned applications, this type of adhesive material has a small adhesive force, It cannot be used because it cannot exhibit sufficient reinforcing properties.

The present invention has been made in view of the above circumstances, and in an atmosphere of temperature from low temperature to high temperature,
It is an object of the present invention to provide a reinforcing material having good initial adhesiveness and release paper releasability and having excellent workability in sticking.

[0008]

In order to achieve the above objects, the reinforcing material of the present invention is a thermosetting resin formed by using an epoxy resin composition containing the following components (A) to (C). A resin layer is a reinforcing material laminated on a reinforcing base material, wherein the ratio of the isocyanate group (X) in the component (C) to the hydroxyl group (Y) in the component (A) is X / Y. = 0.
It is set to 25 to 1.0. (A) A compatible material of an epoxy resin which is liquid at room temperature and a solid epoxy resin having a degree of polymerization of 4 or more. (B) Hardener. (C) Polyisocyanate.

[0009]

The reinforcing material of the present invention uses a compatibilized material [component (A)] of the above-mentioned liquid epoxy resin at room temperature and a solid epoxy resin having a degree of polymerization of 4 or more. And a thermosetting resin layer made of an epoxy resin composition containing an epoxy resin as a main component and having an adhesive property at room temperature, in which the ratio of the isocyanate group in the above polyisocyanate [(C) component] is set in a specific range. It is laminated on a reinforcing base material. Therefore, by the cross-linking reaction between the hydroxyl group and the isocyanate group, to express the cohesive force of the thermosetting resin layer, as a result, the ambient temperature from low to high,
It is a reinforcing material that has both excellent initial tackiness and release paper releasability at the same time, and has extremely good sticking workability.

Next, the present invention will be described in detail.

The reinforcing material of the present invention has a structure in which a thermosetting resin layer is laminated on a reinforcing base material.

The thermosetting resin layer is formed by using an epoxy resin composition.

The above-mentioned epoxy resin composition is obtained by using a compatibilized material (component A) of two specific types of epoxy resins, a curing agent (component B), and a polyisocyanate (component C).

A compatibilized material (component A) of the above-mentioned specific two kinds of epoxy resins is an epoxy resin which is liquid at room temperature and a polymerization degree of 4
It is a compatible material with the above solid epoxy resin. In the present invention, the compatible material means that the liquid epoxy resin at room temperature and the solid epoxy resin are substantially compatible with each other, and are not separated from each other. Therefore, it can be used as long as it causes partial turbidity.

As the above-mentioned liquid epoxy resin at room temperature,
Examples thereof include glycidyl ether type epoxy resins such as bisphenol A type epoxy resins, glycidyl ester type epoxy resins and derivatives thereof. Specifically, it is particularly preferable to use a bisphenol A type epoxy resin.

The solid epoxy resin having a degree of polymerization of 4 or more is derived from the above glycidyl ether type or glycidyl ester type epoxy resins and their derivatives, bisphenol A having a degree of polymerization of 80 to 500, and epichlorohydrin. And a high molecular weight phenoxy resin. Specifically, in particular, bisphenol A
It is preferable to use a type epoxy resin or a phenoxy resin. And in the solid epoxy resin,
If the degree of polymerization is less than 4, the cohesive force of the epoxy resin composition due to isocyanate crosslinking is weakly expressed and desired properties (adhesive force, peeling property, etc.) cannot be obtained, and it is unsuitable for use in the present invention.

The above-mentioned component A as a whole must contain a hydroxyl group. Further, the epoxy group of the epoxy resin in the component A is unreacted, and by heating the thermosetting resin composition at a predetermined temperature, the epoxy group and the curing agent react with each other to exhibit excellent reinforcing properties. become.

The mixing ratio of the liquid epoxy resin (a) and the solid epoxy resin (b) is not particularly limited as long as the obtained thermosetting resin composition exhibits tackiness at room temperature. However, for example, by weight ratio, a / b = 95 /
It is preferably set in the range of 5 to 60/40, and more preferably a / b = 95/5 to 70/30.

A curing agent (B
The component) is not particularly limited as long as it exhibits a curing action by heating, but it is generally sufficient if it is active in the temperature range of 80 to 200 ° C. For example, as the main curing agent for epoxy resin, dicyandiamide, 4,4 '
Examples include diaminodiphenyl sulfone, phenol resin, various acids or acid anhydrides, and polyamidoamine. Among them, it is particularly preferable to use a latent curing agent such as dicyandiamide from the viewpoint of storage stability of the compounded resin composition.

Further, together with the above-mentioned curing agent (component B),
A curing accelerator may be used. As the curing accelerator,
Imidazole derivatives such as 2-n-heptadecyl imidazole, isophthalic acid dihydrazide, guanidine series, N,
Examples thereof include N-dialkylurea derivatives. Among the above curing accelerators, isophthalic acid dihydrazide and N, N-dialkylurea derivatives are preferably used from the viewpoint of storage stability.

The amount of the above-mentioned curing agent (component B) to be compounded is 3 to 100 parts by weight (hereinafter abbreviated as "part") of 100 parts by weight of the compatibilized material (component A) of the two specific epoxy resins.
The proportion is preferably set to 30 parts, and more preferably 4 to 15 parts. Further, when the above-mentioned curing accelerator is used, the compounding amount is preferably set to 10 parts or less, more preferably 0 part, relative to 100 parts of the compatibilized material (component A) of the two specific epoxy resins. 0.5 to 5 parts.
That is, if the compounding amount of the curing agent (B component) is less than 3 parts,
This is because when heated, a sufficient curing action cannot be obtained, and when it exceeds 30 parts, unreacted curing agent remains, tending to deteriorate various properties of the cured product. Further, if the compounding amount of the curing accelerator exceeds 10 parts, the storage stability tends to be remarkably lowered.

The polyisocyanate (C component) used together with the above-mentioned A component and B component is not particularly limited, and a conventionally known polyisocyanate can be used as long as it has at least two isocyanate groups. Examples thereof include diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate and xylene diisocyanate, and polyfunctional isocyanates such as tolylene diisocyanate adducts of trimethylolpropane. Of these, tolylene diisocyanate and diphenylmethane diisocyanate are preferably used from the viewpoints of handleability and economy.

The mixing ratio of the polyisocyanate (C component) is such that the isocyanate group (X) in the polyisocyanate (C component) and all the hydroxyl groups (in the A component) in the compatibilized product of the two specific epoxy resins (component A). The ratio with Y) is X / Y =
It is necessary to set it in the range of 0.25 to 1.0. More preferably, X / Y = 0.4 to 1.0. That is, when the above-mentioned mixing ratio (X / Y) exceeds 1.0,
Although the target thermosetting resin layer can be obtained, it is wasteful because the polyisocyanate is excessively blended. Also,
If the mixing ratio (X / Y) is less than 0.25, sufficient cohesive force cannot be obtained in the thermosetting resin layer to be obtained, and stickiness, resin flow, and peeling from a separator, for example, during resin layer preparation are difficult. This is because such problems occur especially at high temperatures.

In the epoxy resin composition for forming such a thermosetting resin layer, in addition to the above-mentioned components A to C, if necessary, a reaction catalyst, prevention of resin dripping, and reduction of the solution viscosity to reduce wettability. Various additions can be added for the purpose of improving

The above-mentioned reaction catalyst is dibutyltin dilaurate when the reactivity between the hydroxyl group of the compatibilized material (component A) of the two specific epoxy resins and the isocyanate group in the polyisocyanate (component C) is low. Isocyanate reaction catalysts and the like.

Examples of additives to be added for the purpose of preventing sagging of the resin include calcium carbonate, talc, organic bentonite, glass, various short fibers such as vinylon, silicic acid, carbon black and colloidal silica. In this case, the compounding amount of the additives is such that the epoxy resin composition containing these additives is used to prepare the reinforcing material of the present invention, and when the reinforcing material is used for reinforcing the door outer panel of an automobile, it is cured by heating. It is set to such an extent that the adhesive force with the outer plate or the like is not impaired later. Of the various additives that are added for the purpose of preventing sagging, it is preferable to use organic bentonite from the viewpoint of sagging prevention characteristics and stability over time. The compounding amount is preferably set to 2 to 30 parts with respect to 100 parts of the polymer component (the total amount of the component A and the thermoplastic resin, the rubber component and the like which are compounded as necessary) in the epoxy resin composition. It is more preferably 4 to 15 parts.

Examples of additives to be added for the purpose of lowering the solution viscosity and improving the wettability include reactive diluents such as butyl glycidyl ether and monoglycidyl ether of long chain alcohol, and phthalic acid plasticizers such as dioctyl phthalate. Agents and the like. And the compounding quantity of these additives is the compatible material (A
Ingredient) It is usually preferable to set the ratio to 3 to 30 parts with respect to 100 parts. It is more preferably 5 to 10 parts.

The thin steel plate to which the reinforcing material of the present invention is applied often has rust-preventive oil or the like adhered thereto, so that the epoxy resin composition may be applied to such oil-surfaced steel plate. Various rubber components may be added to the product. As the rubber component, butyl rubber, isoprene rubber, butadiene rubber, styrene-isoprene copolymer rubber or the like can be used. Among these rubber components, it is preferable to use butyl rubber or isoprene rubber based from the viewpoint of fixability to the oil surface steel plate. The compounding ratio of the rubber component is 100% of the specific two kinds of the epoxy resin compatible components (A component).
Usually, it is preferable to set the ratio to 50 parts or less with respect to the parts. It is more preferably 5 to 20 parts.

Furthermore, after the epoxy resin composition is cured by heating, the resin composition is foamed to increase the thickness of the cured resin layer, whereby the reinforcing property can be further improved. A foaming agent may be added to foam such a resin composition. As the foaming agent,
Conventionally known materials are used, and examples thereof include a thermally decomposable foaming agent such as azodicarbonamide, and hollow spheres that expand and expand when heated.

A preferred combination of the compounding ingredients constituting the epoxy resin composition is a bisphenol A type epoxy resin and a flexible epoxy resin as a liquid epoxy resin at room temperature, and a solid epoxy resin having a degree of polymerization of 4 or more. A compatible material (component A) using a bisphenol A type epoxy resin having a degree of polymerization of 4 or more, dicyandiamide as a latent curing agent as a curing agent (component B), and diphenylmethane diisocyanate as a polyisocyanate (component C) And a liquid isoprene rubber, a filler (talc, calcium carbonate), organic bentonite, and a hydrazide foaming agent as other additives.

The reinforcing base material laminated on the thermosetting resin layer formed of the epoxy resin composition is used for improving the reinforcing property, and is laminated on one surface of the thermosetting resin layer. .

As the reinforcing base material, various fiber base materials,
Metal foil or the like is used. Specific examples thereof include glass cloth, glass mat, glass roving, polyester woven cloth, aluminum foil, and stainless steel foil.

The reinforcing material of the present invention can be manufactured, for example, as follows. That is, first, the above-mentioned liquid epoxy resin at room temperature and a solid epoxy resin having a degree of polymerization of 4 or more are heated and mixed to form a compatible material (A component), and then the A component, the B component, the C component, and if necessary. An epoxy resin composition is produced by stirring and mixing various additives accordingly.

Then, using the above epoxy resin composition,
A sheet material made of thermosetting resin is formed by a direct pressure press or various applicators via release paper. And
By peeling off the release paper and laminating the reinforcing base material on one surface of the sheet-like material, the reinforcing material of the present invention comprising the thermosetting resin layer and the reinforcing base material can be manufactured.

Further, in the thermosetting resin layer, A
In order to make the reaction between the hydroxyl group and the isocyanate group in the component more complete, it may be further heat-treated after being formed into a sheet. This heat treatment accelerates the crosslinking reaction between the hydroxyl group and the isocyanate group, and is set so that the reaction (curing reaction) between the epoxy group in the component A and the curing agent hardly progresses. Specifically, the temperature is set to 50 ° C. or lower for about 5 hours. Under the heat treatment conditions with such settings, usually, the reaction between the epoxy group and the curing agent hardly occurs.

In the reinforcing material thus manufactured, the thickness of each layer is appropriately set. For example, the thickness of the thermosetting resin layer is preferably set to 0.2 to 3 mm, and particularly preferably. It is preferably 0.4 to 1.5 mm.
The thickness of the reinforcing base material is preferably set to 0.03 to 0.4 mm, particularly preferably 0.05 to 0.3 mm.
mm. The total thickness of the entire reinforcing material can be appropriately set depending on its application, but is usually 0.3.
It is set to ˜5 mm, preferably 0.5 to 3 mm. That is, if the thickness is less than 0.3 mm, a problem occurs in the strength of the reinforcing material after heat curing, and if the thickness exceeds 5 mm, the strength becomes too strong and the thin steel sheet as the adherend is distorted. This is because problems will occur.

In the reinforcing material thus obtained, the thermosetting resin layer is in a flexible uncured state having tackiness at room temperature, but is isocyanate-crosslinked with the polyisocyanate as the component C. Therefore, it has an appropriate cohesive force. Therefore, even in a low temperature atmosphere such as in winter, it has sufficient adhesiveness as compared with the conventional one, and can be easily attached to a thin steel plate to be adhered. In addition, since the cohesive force of the thermosetting resin layer is maintained even in a high temperature atmosphere such as in summer, the peelability from the release paper is good, and the adhesive residue and work on the release paper as in the conventional It is possible to prevent the resin layer from adhering to the person and the adhesive from sticking out, thereby obtaining good workability.

[0038]

As described above, the reinforcing material of the present invention is 2
A thermosetting resin layer made of an epoxy resin composition containing a specific compatible epoxy resin component (A component), a curing agent (B component), and a polyisocyanate (C component) is used as a reinforcing base material. It is a laminated reinforcing material. Moreover, the ratio of the isocyanate group (X) in the C component and the hydroxyl group (Y) in the A component is set within a specific range. For this reason,
By the cross-linking reaction of the isocyanate group and the hydroxyl group, the cohesive force of the thermosetting resin layer is expressed, and as a result, from a low temperature to a wide range of ambient temperature, excellent initial tackiness and release paper releasability. It becomes possible to make them compatible.
Therefore, the sticking workability becomes extremely good, and the work efficiency is improved.

Next, examples will be described together with comparative examples.

[0040]

Example 1 Bisphenol A type epoxy resin (epoxy equivalent 190) 35 as an epoxy resin which is liquid at room temperature
And 30 parts of a flexible epoxy resin (molecular weight 650),
35 parts of bisphenol A type epoxy resin (epoxy equivalent 930, degree of polymerization 4.4) as a solid epoxy resin was heated and melted at 120 to 150 ° C. to prepare a compatible material.
While maintaining the compatible material at 50 ° C., 10 parts of liquid isoprene rubber, 80 parts of talc, and 10 parts of organic bentonite were added thereto.
Part, dicyandiamide 5 parts, foaming agent (hydrazide foaming agent) 2 parts, diphenylmethane diisocyanate (MD
I) 16.6 parts, dibutyltin dilaurate (DBTL)
0.01 part was sequentially added and thoroughly mixed with a two-roll mill.

The epoxy resin composition thus obtained was adjusted to a thickness of 1 mm by a direct pressure press through a release paper, and the release paper on the upper surface was removed to remove the glass cloth as a reinforcing base material (area weight: 220 g / m ² ) were laminated. In that state, 50 ℃ ×
After heat treatment for 5 hours, the hydroxyl group in the epoxy resin component and the isocyanate group in diphenylmethane diisocyanate, which is polyisocyanate, were cross-linked to obtain a target reinforcing material having adhesiveness at normal temperature.

[0042]

Examples 2 to 7, Comparative Examples 1 to 5 Epoxy resin compositions were prepared in the same manner as in Example 1 with the components and blending amounts shown in Tables 1 to 3 below. Then, the intended reinforcing material was obtained by using glass cloth (basis weight: 220 g / m ² ) as a reinforcing base material and going through the same steps as in Example 1.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

Using the reinforcing material thus obtained,
The adhesiveness, releasability and reinforcing property were measured and evaluated by the following evaluation methods. The results are shown in Tables 4 and 5 below.
Shown in

[Adhesiveness Test] As shown in FIG. 1, an adhesiveness evaluation test jig 7 was prepared, and an oil surface steel plate 2 whose surface was lightly wiped with a dry cloth was applied to the reinforcing materials obtained in Examples and Comparative Examples. Test piece 1 (width: 25 mm x length: 50 mm) is attached, and test piece 1
The impact test of inclining the pasted oil surface steel plate 2 from the vertical frame 3 to an angle (θ) of 30 degrees and colliding with the vertical frame 3 from that time point was repeated. Then, the number of times until the test piece 1 fell off from the oil surface steel plate 2 was measured, and the adhesive force was evaluated by this number of times. This test was performed at a temperature of 35 ° C and a temperature of 8
It was performed in a test room at 0 ° C. As a result, those that did not fall off even after 10 impacts were evaluated as ◯, those that fell out between 3 and 10 impacts were marked as Δ, and those that fell out after 2 impacts were evaluated as ×.
Displayed as.

[Releasability of Release Paper] Width 50 mm × Length 150
Releasing paper with mm reinforcement (paper release paper treated with silicone)
After sticking to, the mixture was allowed to stand for 1 hour in an atmosphere of each temperature of 5 ° C and 40 ° C. Then, the peeled state when the release paper was peeled off was observed and evaluated in the atmosphere. As a result, the release paper with no adhesive residue and easy peeling was indicated by ○, the partial release paper adhesive residue was indicated by Δ, and the release paper that could not be peeled off was indicated by X. .

[Reinforcing Test] A reinforcing material is molded into a size of width 50 mm × length 150 mm, which is 0.8 mm thick ×
It was attached to a steel plate having a width of 80 mm and a length of 200 mm. This was heat-cured for 30 minutes in an atmosphere at a temperature of 180 ° C., and then cooled to room temperature to obtain a test sample. Then, a support base was prepared in which two vertical flat plates (width 50 mm) having an inverted U-shaped cross section with a radius of curvature of 5 mm were arranged in parallel at a distance of 100 mm, and the test sample was oriented to the support in the longitudinal direction. It hung horizontally in the state. Then, a load was applied to the central portion of this test sample from above with a vertical flat plate (width 50 mm) having a U-shaped cross section with a radius of curvature of 10 mm, and the maximum bending stress (kg / 80 mm width) at this time was measured.

[0050]

[Table 4]

[0051]

[Table 5]

From the results of Tables 4 and 5 above, Comparative Example 1
Since the product did not contain an isocyanate component, cohesive force due to isocyanate crosslinking could not be obtained, and the product could not be peeled from the release paper in a high temperature atmosphere. Further, in the product of Comparative Example 2, the adhesive strength at low temperature was low, and the peelability at high temperature had a problem. Then, the product of Comparative Example 3 was inferior in adhesiveness at low temperature and had a problem in peelability at high temperature. Furthermore, in the product of Comparative Example 4, the adhesive strength at low temperature was low, and peeling from the release paper was not possible in a high temperature atmosphere. On the other hand, in the product of Example, the cohesive force of the thermosetting resin layer is improved in the uncured state by the isocyanate cross-linking of the hydroxyl group and the isocyanate group in the epoxy resin component. Therefore,
It had excellent adhesive strength even under atmospheres with different temperatures (8 ° C., 35 ° C.), and there was no problem in releasability. Further, in terms of reinforcing property, it has a high bending strength and can be used as a reinforcing material without any problem. From this fact, the example product can be used in a wide range of temperatures, and when manufacturing the thermosetting resin layer, the material management and the production management thereof are rationalized, and the inventory management is facilitated. There is an effect that the material can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a test method of an adhesive strength test using an adhesive strength evaluation test jig.

Claims (1)

[Claims] 1. A reinforcing material in which a thermosetting resin layer formed using an epoxy resin composition containing the following components (A) to (C) is laminated on a reinforcing base material. The ratio of the isocyanate group (X) in the component (C) and the hydroxyl group (Y) in the component (A) is X / Y = 0.25 to 0.25.
Reinforcing material characterized by being set to 1.0. (A) A compatible material of an epoxy resin which is liquid at room temperature and a solid epoxy resin having a degree of polymerization of 4 or more. (B) Hardener. (C) Polyisocyanate.