JP2003019768A - Coating-type steel sheet reinforcing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developed lightweight reinforcing material with an enhanced steel sheet reinforcing effect compared with a conventional reinforcing material, without the problem that an inorganic lightweight filler or an extender pigment melts out of an uncured reinforcing material and consequently, contaminates a conversion treating solution, when an automotive body is soaked in the conversion treating solution in the steps from the application of the reinforcing material to a conversion treatment of an automotive pressing process. SOLUTION: This coating-type steel sheet reinforcing material is characterized in that it is a normal temperature-curable two-pack type epoxy coating material and exhibits flexibility after the material is cured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating type reinforcing material mainly used for automobile steel sheets.

[0002]

2. Description of the Related Art Reducing vehicle weight in the automobile industry has always been an important issue, and steel sheets used in automobiles have been thinned to the limit of safety and structural requirements. For this reason, especially for the steel plate forming the outside of the automobile,
A steel plate reinforcing material, which is usually called a dent material, is attached to an inner portion of an automobile or heat-sealed to contribute to improvement of rigidity of the steel sheet.

These reinforcing materials are rubber-based, bituminous-based, synthetic resin-based materials such as alkyd resin, epoxy resin, urethane resin, urea resin, etc., which are appropriately mixed with fillers and additives, and mixed and kneaded. It is processed into a desired size and shape by a conventionally known processing method and is attached to a necessary portion of a steel plate.

[0004] Among them, the applicant of the present invention has responded to the demands of the customers, such as the construction of a reinforcing material in a place where it is difficult to attach the molded material by a reinforcing material, or the development of a lighter reinforcing material. An invention relating to a coating type steel plate reinforcing composition is disclosed in Japanese Patent Application No. 11524/1993.
I am applying for No. 3.

[0005]

In the above-mentioned invention, since the application type is adopted, it is possible to apply only the required amount of the reinforcing material to the required site, and thus the waste is eliminated in the operation, and
Labor saving has been achieved by using a painting robot or automatic painting machine to apply the reinforcing material.

However, since the coating type reinforcing material according to the present invention uses the thermosetting resin, it is still heated in the process from the coating in the pressing process of the automobile to the chemical conversion treatment process. No, it is in an uncured state. For this reason, when an automobile body coated with a reinforcing material is dipped in a chemical conversion treatment solution, inorganic lightweight fillers and extender pigments may dissolve from the uncured reinforcement material, which may cause a problem of contaminating the chemical conversion treatment solution. There was a nature. Therefore, the present invention aims to solve the above-mentioned problems of the invention and to develop a steel plate reinforcing effect and a lightweight reinforcing material.

[0007]

[Means for Solving the Problems] In order to solve the above problems, the present inventor has, as a result of diligent research, developed the following coating-type reinforcing material and a method of constructing the reinforcing material, the gist of which is It is as follows. A coated steel plate reinforcing material characterized by being a room temperature curing two-component epoxy paint. The coated steel sheet reinforcing material as described above, wherein the two-pack type epoxy coating has flexibility after curing. The details will be described below.

The steel plate reinforcing material used in the present invention is composed of a single-layer coating material, the main component of which is a room temperature curing two-component type coating material made of epoxy resin.

The epoxy resin is required to have flexibility after being cured by heating, and it is necessary to select an epoxy resin, a curing agent, and other compounds which satisfy the requirement. There are a plurality of evaluation methods for determining whether or not the material has flexibility after heat curing, but in the present invention, JIS B 7
JIS using the Erichsen tester specified in 729
It was decided to evaluate by the Erichsen value measured by the Erichsen test method specified in B 7777.
That is, a main agent, a curing agent, and the like are mixed, a sheet-like material having a thickness of 100 μm is prepared by an appropriate method such as a doctor blade, heated at 180 ° C. for 30 minutes, and then cooled to room temperature.
The Erichsen value was measured by the above-mentioned test method and evaluated as flexibility. The Erichsen value was evaluated to be 5 mm or more and to be flexible, and 7 mm or more to be extremely flexible. First, bisphenol A was used as the main component of the epoxy resin.
A method of adding and mixing a flexible (providing) type epoxy resin to a basic epoxy resin system such as a mold or bisphenol F type, or using only a flexible (providing) type epoxy resin. . Flexible (giving) type epoxy resin is supplied in various grades from various epoxy resin manufacturers, but dimer acid epoxy resin, dimer acid modified epoxy resin, rubber modified epoxy resin, (polyvalent) alcohol ether Type epoxy resin, polyglycol type epoxy resin, urethane modified epoxy resin and the like.

When the curing agent is compounded, it is necessary to compound it so that it has flexibility after heat curing, but basically it is possible to select it from conventionally known epoxy resin curing agents. That is, aliphatic amine, aromatic amine, acid anhydride, urea resin, melamine resin, and phenol resin can be exemplified. Aliphatic amines include diethylenetriamine (DTA), triethylenetetramine (TETA)
Etc., and an adduct having an amino group at these terminals is used as meta-phenylene diamine (MP
D), diaminodiphenylmethane (DDM) and diaminodiphenylsulfone (DDS) can be used.

The coated steel plate reinforcing material according to the present invention is
It is desirable that the coating type steel plate reinforcing material itself has a shape-retaining force due to the progress of the curing reaction between the epoxy resin and the curing agent after 1 to 2 hours have passed after the coating. This is for the following reason. In an automobile manufacturing line, when the coating-type reinforcing material according to the present invention is applied in a pressing step, a steel sheet is subsequently welded in a welding step to remove rust-preventing oil adhering to the steel sheet, a dewatering step, a degreasing step However, in these steps, the water flow necessary for washing with hot water, shower, etc.
In some cases, the reinforcing material may be applied directly or indirectly. At this time, if the reinforcing material is not sufficiently hardened, the reinforcing material may fall off from the steel sheet due to the effect of water flow or shower due to hot water washing, or even if it is escaped, the coating film on one side becomes thicker. There is a risk of deformation. Although the falling-off is obviously a defect, even when it is deformed, a large stress may be generated on the side where the coating film of the reinforcing material is thickened during heat curing, and a defect may occur that the steel sheet is distorted. The coating type steel plate reinforcing material applied to prevent these problems has sufficient shape-retaining power after 1 to 2 hours after application even before heat curing, so that water flow in the hot water washing step and Can withstand a shower.

Another formulation is an epoxy reactive diluent. In order to improve the coating workability of the steel plate reinforcing material, it is necessary to reduce the viscosity of the epoxy resin coating material, and for this purpose, the blending of an epoxy reactive diluent is desirable. Various diluents are known as the present diluent and can be used without particular limitation.

Other compounds include fillers and additives. As the filler, various extender pigments and coloring pigments such as calcium carbonate, barium sulfate, talc, clay, kaolin, zinc white, titanium oxide, silica and alumina, plastic balloons, glass balloons, ceramic balloons, silica balloons are also used. Examples include various lightweight low specific gravity fillers such as Shirasu balloon. Other additives include dehydrating agents, hygroscopic agents, anti-sagging agents, thixotropic additives, dispersants, UV absorbers, high boiling point solvents for improving coating workability, epoxy reactive diluents, plasticizers, oil surface adhesion Examples thereof include powder rubber for increasing the effect and acrylic resin for increasing the steel plate reinforcing effect. The addition amount of these additives is appropriately 0 to 10% by mass.

The coating-type reinforcing material according to the present invention can be produced by using a conventionally known coating disperser. That is,
It is a disperser such as a dissolver, a planetary mixer, an open kneader, a vacuum kneader, a roll mill, a ball mill, and a Glen mill.

If the reinforcing material according to the present invention is to be applied to a necessary place, the reinforcing material is pressure-fed by a pressurizing machine such as an airless pump, a nozzle of a required size is used, and various conventionally known coating machines are used. It is applied to any desired place such as a car door panel, quarter panel, rear gate panel, etc.

As a method of mixing the main agent and the curing agent, it is conceivable that the two are mixed in an equivalent ratio in advance, and the mixture is pressure-fed and applied by a coating machine. In this case, the coating operation is continuous. However, if there is a line break for lunch break or for some other reason, the curing reaction may proceed in the pipe and plug the pipe. . In addition, the main agent and the curing agent are pressure-fed by separate pipes, and a conventionally known two-liquid mixer such as a collision type mixer is arranged immediately before the coating machine to apply the reinforcing material mixed at an equivalence ratio. The method can be illustrated. In this case, it is possible to prevent embolism in the piping and the coating machine by washing only the portion ahead of the mixer. Basically, it is desirable to use extrusion coating instead of spray coating by atomization. By coating with a coating device such as a slit nozzle or a swirl type nozzle, a reinforcing material having a film thickness necessary for reinforcing a steel plate can be coated with one application.

Further, the piping and the coating nozzle are set at 30 to 70 ° C.
By heating and painting the reinforcing material, it is possible to reduce the viscosity of the reinforcing material, form a more uniform and smooth coated surface of the reinforcing material, and obtain stable quality and reinforcing effect. If the heating temperature is lower than 30 ° C, the viscosity and the viscosity are not sufficiently reduced, and if the heating temperature is higher than 70 ° C, the reinforcing material may gel before coating.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In order to provide an understanding of the present invention, examples will be described below. Needless to say, the present invention is not limited to the examples below.

[0019]

Example 1 100 parts by mass of a bisphenol F type epoxy resin having an epoxy equivalent of about 350, 50 parts by mass of an epoxy reactive diluent having an epoxy equivalent of about 200 as a main agent, and an amine adduct of diethylenetriamine (DTA) as a curing agent. 50 parts by mass of curing agent, calcium carbonate 300
30 parts by weight of the additive and 30 parts by weight of the additive are mixed and dispersed by a planetary mixer, and the main agent and the curing agent are pressurized and pressure-fed by an airless pump, and the curing agent of the main agent is reacted at a reaction equivalent ratio by a mixer arranged immediately before the nozzle. By mixing and applying the pipe and nozzle to a slit nozzle heated to about 50 ° C to a 0.8 mm thick steel plate for automobiles with anti-rust oil applied, with a coating thickness of 1.0 mm, curing reaction at room temperature Thus, the reinforcing material 1 was obtained. The Erichsen value of the reinforcing material 1 measured separately was 7 mm, and it was evaluated that the reinforcing material 1 was extremely flexible.

[0020]

Example 2 100 parts by mass of a bisphenol F type epoxy resin having an epoxy equivalent of about 300, 50 parts by mass of an epoxy reactive diluent having an epoxy equivalent of about 250 as a main agent, and an amine adduct of diethylenetriamine (DTA) as a curing agent. 50 parts by mass of curing agent, calcium carbonate 300
30 parts by weight of the additive and 30 parts by weight of the additive are mixed and dispersed by a planetary mixer, and the main agent and the curing agent are pressurized and pressure-fed by an airless pump, and the curing agent of the main agent is reacted at a reaction equivalent ratio by a mixer arranged immediately before the nozzle. By mixing and applying the pipe and nozzle to a rotating rotary nozzle heated to about 50 ° C., it is applied at a coating thickness of 1.0 mm on a 0.8 mm thick steel plate for automobiles on which rust-preventing oil is adhered, and at room temperature. The reinforcing material 2 was obtained by the curing reaction. The Erichsen value of the reinforcing material 2 measured separately was 8 mm, and it was evaluated that the reinforcing material 2 was very flexible.

[0021]

Example 3 100 parts by mass of a bisphenol F type epoxy resin having an epoxy equivalent of about 250 as a main agent, 50 parts by mass of an epoxy reactive diluent having an epoxy equivalent of about 250, and an amine adduct of diethylenetriamine (DTA) as a curing agent. 50 parts by mass of curing agent, calcium carbonate 300
30 parts by weight of the additive and 30 parts by weight of the additive are mixed and dispersed by a planetary mixer, and the main agent and the curing agent are pressurized and pressure-fed by an airless pump, and the curing agent of the main agent is reacted at a reaction equivalent ratio by a mixer arranged immediately before the nozzle. By mixing and applying the pipe and nozzle to a slit nozzle heated to about 50 ° C to a 0.8 mm thick steel plate for automobiles with anti-rust oil applied, with a coating thickness of 1.0 mm, curing reaction at room temperature Thus, the reinforcing material 3 was obtained. The Erichsen value of the reinforcing material 3 measured separately was 8 mm, and it was evaluated that the reinforcing material 3 was very flexible.

[0022]

Comparative Example 250 parts by mass of TDI urethane prepolymer of lactam block, 100 parts by mass of polyurethane resin containing reaction equivalent of polyester polyol, 300 parts by mass of bisphenol A type epoxy resin and dicyandiamide latent curing agent, 30 parts by mass of glass balloon, carbonic acid 200 parts by mass of calcium and 30 parts by mass of additives were mixed and dispersed by a planetary mixer to obtain a coating type reinforcing material 4. The coating type reinforcing material 4 is pressure-fed by an airless pump, and at the same time, a coating thickness of 1 is applied to a 0.8 mm thick steel plate for automobiles on which rust-preventing oil is adhered by a slit nozzle in which the pipe and the nozzle are heated to about 50 ° C. It was applied at 0.5 mm to obtain a reinforcing material 4. The Erichsen value of the reinforcing material 4 measured separately was 3 mm, and it was evaluated that the reinforcing material 4 had no flexibility.

[0023]

[Test Method] (1) The appearance of the steel sheet after the coating and hardening of the reinforcing material was observed and examined for any abnormalities such as distortion. (2) Reinforcing properties of each test piece were measured after measuring the mass per 1 m ² . The reinforcing property was measured by a tensile tester. Each test piece was placed on a 3-point bending type deformation measuring jig having a span of 100 mm, the test piece was compressed at a compression rate of 5 mm / min, and the load when the test piece was deformed by 1 mm was measured.
This is multiplied by the gravitational acceleration to provide reinforcement.

[0024]

[Results] (1) No abnormalities were found in the appearance of the steel sheets for the exterior reinforcement materials 1 to 4. (2) Reinforcing property (unit is N)

[0025]

EFFECTS OF THE INVENTION Since the reinforcing material of the present invention is a coating type, the conditions required for attaching a reinforcing material of a conventional molded product can be relieved significantly. Since it becomes possible to apply the reinforcing material to the places where the attachment is difficult or impossible, the places where the steel plate reinforcement is applied are significantly increased. Further, since it is a coating work, the work can be automated by using an automatic coating machine or a robot coating machine as the coating machine. Further, since the reinforcing material according to the present invention cures at room temperature within 1 to 2 hours after application, it is applied in the pressing step, and the coating film is hardened when shifting to the chemical conversion treatment step, thus contaminating the chemical conversion treatment solution. Since there is no fear and a lightweight hollow filler or the like can be mixed with the reinforcing material, it is possible to freely reduce the specific gravity and weight of the reinforcing material as needed. Further, since the adhesive force of the reinforcing material according to the present invention is extremely strong, even for a steel sheet for automobiles in which rust preventive oil is present on the surface before chemical conversion treatment,
It can be easily attached to form a reinforcing material. In addition, since the curing reaction at room temperature can maintain the shape by necessary and sufficient curing in 1 to 2 hours elapsed time, after applying the reinforcing material in the pressing process, a strong water flow in the post-process of hot water washing / degreasing process, chemical conversion treatment. Even after the steps, the reinforcing material is not likely to change its shape, fall off, shift, peel off or the like.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4F100 AA08H AB03B AH03H AK53A                       BA02 CA02 CA23 GB32 JB13A                       JK06 JK17A JL00 JL02

Claims (2)

[Claims] 1. A coating type steel plate reinforcing material, which is a room temperature curing two-component epoxy paint. 2. The coated steel sheet reinforcing material according to claim 1, wherein the two-pack type epoxy paint has flexibility after curing.