JP2002293884A - Normal-temperature curing composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a normal-temperature composition with which coatable time is extended and a curing property is maintained in high solid content when used as a paint. SOLUTION: The normal-temperature curing composition is composed of an epoxy resin, an amine curing agent, an unsaturated fatty-acid modified material of a liquid epoxy resin, and a dryer, wherein solid-content weight of the unsaturated fatty-acid modified material is 50-20% of solid-content weight of the above epoxy resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cold-setting composition,
In particular, it relates to a room temperature curable composition having a high solid content.

[0002]

2. Description of the Related Art An epoxy-amine curing system is applied to a large structure to enhance its corrosion resistance because the curing reaction proceeds at room temperature and the adhesiveness to a substrate is excellent. In general, epoxy resins are often solid and diluted with an organic solvent for use in paints. However, as interest in the environment has increased in recent years, it has become necessary to reduce volatile organic compounds (VOCs) contained in paints. Have been.

[0003] Usually, in the case of the above-mentioned epoxy-amine curable coating material, an epoxy component as a base resin and an amine as a curing agent component are mixed immediately before use and applied. VOC
When a liquid epoxy resin is used in order to reduce the amount of the organic solvent used, the time that can be applied is shorter than that of a conventional epoxy resin, so that the workability is a new problem. This is because, in the case of a conventional paint using a solid epoxy resin, if the solvent evaporates, it will be in an apparently cured state even if crosslinking has not progressed, whereas if a liquid epoxy resin is used, it will be cured. This is because a cured coating film cannot be obtained unless the reactivity of the epoxy-amine is increased by using a promoter or the like to increase the reactivity. Heretofore, it has not been possible to achieve a good balance between application time and curability.

Therefore, it is conceivable to use a mono- or diepoxy compound as a reactive diluent. However, since the lower the viscosity, the higher the volatility, when measuring the VOC based on the heating residue, these are easily counted as VOC. In addition, there are concerns about the effects of these compounds on the body, and there has been a problem in their use.

[0005] On the other hand, Japanese Patent Application Laid-Open No. 4-211420 discloses a liquid epoxy resin in which a part of epoxy groups is modified with an unsaturated fatty acid, and this is combined with an amine curing agent as a base resin. The purpose of the modification with the unsaturated fatty acid is to lower the viscosity and improve the solubility in an amine curing agent, and there is no disclosure of the contribution of unsaturated bonds to curing.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a room temperature curable composition which can extend the coating time while maintaining curability at a high solid content when formed into a paint. That is.

[0007]

The room temperature curable composition of the present invention comprises an epoxy resin, an amine curing agent, a liquid epoxy resin-modified unsaturated fatty acid, and a drier, and comprises the unsaturated fatty acid-modified product. The solid content weight of the product is 5 to 20% based on the solid content weight of the epoxy resin. Here, the unsaturated fatty acid used in the production of the modified unsaturated fatty acid has an acid value of 175 to 20.
5. The iodine value may be 120-205. Further, the modification rate of the modified unsaturated fatty acid may be 90% or more.
The cold-setting composition of the present invention further comprises a volume pigment concentration of 25
４５45% pigment and a viscosity at 25 ° C. of 10
The non-volatile content when adjusted at 25 ° C. to 00 to 2000 cps can be 75% or more.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The cold-setting composition of the present invention comprises an epoxy resin, an amine curing agent, a liquid epoxy resin-modified unsaturated fatty acid, and a dryer.

In the cold-setting composition of the present invention, a modified unsaturated fatty acid of a liquid epoxy resin is used as a reactive diluent. The modified unsaturated fatty acid of the liquid epoxy resin is obtained by adding a carboxyl group of the unsaturated fatty acid to the epoxy group of the liquid epoxy resin. Epoxy groups may remain in the unsaturated fatty acid modified product, but the modification rate is preferably 90% or more. The modification ratio as used herein is a ratio of the epoxy group of the liquid epoxy resin which has undergone an addition reaction with a carboxyl group, which is an unsatisfactory ratio based on the epoxy group equivalent of the liquid epoxy resin used in the modification. It is expressed by the ratio of the equivalent of the carboxyl group of the saturated fatty acid. More preferably, the modification rate is substantially 100%.

As the liquid epoxy resin, those which are liquid at room temperature and have at least two or more epoxy groups in a molecule can be used. These include bisphenol A type, bisphenol F type, bisphenol AD type, and phenol novolak type, and bisphenol A type epoxy resin is preferred from the viewpoint of versatility. As a specific example of a commercially available liquid bisphenol A type epoxy resin, Epicoat 82 manufactured by Yuka Shell Co., Ltd.
7, 828, DER-330, 331 manufactured by Dow, Epicron # 840, 850 manufactured by Dainippon Ink and Chemicals, Epototo YD-127, 128 manufactured by Toto Kasei, AER330, 331 manufactured by Asahi Kasei, and the like. Can be.

On the other hand, the unsaturated fatty acid for modifying the liquid epoxy resin preferably has an acid value of 150 to 220 and an iodine value of 50 to 210. Outside of this range, the resulting unsaturated fatty acid modified product may not function as a reaction diluent. A more preferred acid value is 17
5 to 205, more preferably 120 to 205
It is. Specific examples of the unsaturated fatty acids include tung oil fatty acids, soybean oil fatty acids, linseed oil fatty acids, castor oil fatty acids,
Vegetable oil fatty acids such as tall oil fatty acids, and linoleic acid and linoleic acid distilled therefrom can be exemplified. The unsaturated fatty acid may be a mixture of those exemplified above.

The addition reaction between the liquid epoxy resin and the unsaturated fatty acid can be carried out by a method well known to those skilled in the art. For example, the reaction can be performed by mixing a liquid epoxy resin and an unsaturated fatty acid in a solvent and heating the mixture to 100 to 160 ° C. in the presence of a catalyst such as a quaternary ammonium salt. The progress of this addition reaction can be confirmed by tracking the disappearance of the peak based on the epoxy group in the IR spectrum. In addition, when making the modification rate of the obtained unsaturated fatty acid modified product 90% or more, the amount of the carboxyl group of the unsaturated fatty acid with respect to the amount of the epoxy group of the liquid epoxy resin may be made 90% or more.

When the above addition reaction is carried out using a solvent, it is preferable to distill off the used solvent under reduced pressure after the completion of the reaction. By doing so, the solid content of the resulting unsaturated fatty acid modified product can be made substantially 100%.

The modified unsaturated fatty acid thus obtained preferably has a modification rate of 90% or more.
If it is less than 90%, curing due to unsaturated bonds may not proceed sufficiently. More preferably, the modification rate is substantially 100%.

The epoxy resin contained in the cold-setting composition of the present invention may be a normal epoxy resin having two or more epoxy groups capable of forming a crosslinked coating film, and having an epoxy equivalent of 180 to 2100. Some can be used,
In general, a liquid is used for high solid differentiation. As the liquid, those exemplified above as the raw materials for the modified unsaturated fatty acid can be used. In addition, it is preferable to use the same one used as a raw material of the modified unsaturated fatty acid. The above epoxy resins may be used as a mixture of two or more.

On the other hand, as the amine curing agent contained in the room-temperature curable composition of the present invention, a well-known amine curing agent can be used. For example, aliphatic polyamines such as diethylenetriamine and triethylenetetramine, alicyclic polyamines such as isophoronediamine, 4,4′-diamino-dicyclohexylmethane and diaminocyclohexane, and aromatics such as diaminodiphenylmethane, metaxylenediamine and phenylenediamine Examples thereof include polyamines and their epoxy resin adducts, modified Mannich products, modified adducts, polyamidoamines, and polyamide resins. These are preferably used depending on their reactivity, and two or more of them can be used in combination.

Further, the room temperature curable composition of the present invention contains a dryer. This dryer functions to crosslink the unsaturated bonds of the above-mentioned modified unsaturated fatty acid. As the above-mentioned dryer, any one may be used as long as it is commonly used for paints. Among them, particularly typical ones are cobalt,
Examples thereof include naphthenates such as vanadium, manganese, cerium, lead, iron, calcium, zinc, zirconium, cerium, nickel and tin, octylates, and resinates.

In the cold-setting composition of the present invention, the solid content of the unsaturated fatty acid-modified product is 5 to 20% of the solid content of the epoxy resin. If it is less than 5%, the time that can be applied cannot be extended, and if it exceeds 20%, a problem occurs in the initial curability.

The ratio of the epoxy resin to the amine curing agent is preferably such that the equivalent ratio of the epoxy group to the active hydrogen of the amino group is 1 / 1.5 to 1.5 / 1. . Outside of these ranges, the desired effect may not be obtained or the physical properties of the obtained film may be adversely affected. Further, it is more preferable that the equivalent of the epoxy group exceeds the equivalent of active hydrogen of the amino group. In addition, the amount of the metal can be set in the range of 0.01 to 1 part by weight with respect to 100 parts by weight of the modified unsaturated fatty acid.

When used as a paint, the cold-setting composition of the present invention usually further contains a pigment. When a pigment is contained, its content is preferably 25 to 45% by volume pigment concentration, and more preferably 30 to 40%. As the pigment, conventionally well-known pigments can be used, and pigments such as a coloring pigment, an extender pigment, and an antirust pigment can be used. Examples of the color pigment include inorganic color pigments such as titanium oxide, carbon black, and red iron oxide.
Examples of the extender include talc, calcium carbonate, barium sulfate, clay, silica, and mica. Further, scaly pigments such as stainless steel and MIO can be used. Examples of the rust-preventive pigment include zinc oxide and phosphorus molybdenum which form a rust-preventive coating layer with a stable compound, such as zinc oxide and strontium chromate, which are oxidative rust-preventive pigments, such as alkaline pigments such as lead oxide and lead tin. Zinc acid, aluminum phosphate, and the like.

In addition to the above components, the room temperature curable composition of the present invention can contain other usual various additives. Examples of the additive include a curing accelerator, a pigment dispersant, an antifoaming agent, a leveling agent, and a sagging agent. Also,
A solvent is appropriately used for adjusting the viscosity.

When the room temperature curable composition of the present invention is formed into a paint at a volume pigment concentration of 25 to 45% and the viscosity at 25 ° C. is adjusted to 1000 to 2000 cps, which is suitable for coating, the non-volatile content is 75% or more. Preferably, it can be set to a high value of 80 to 90%. This non-volatile content is equivalent to 11
It is determined by heating at 0 ° C. for 1 hour. In addition, the room-temperature-curable composition of the present invention can have a high non-volatile content of 80% or more without containing a pigment.

The cold-setting composition of the present invention is usually used in the form of a two-pack type in which an amine curing agent and other components are separated and mixed when used. Although the object to be coated is not particularly limited, application to a structure composed of concrete, steel plate, and steel frame is effective. Various application methods can be used, but usually, spraying or brush coating is preferably used. The coating thickness is 50-250 when dry
It is preferably performed to be μm. Since the composition of the present invention cures at room temperature, the time during which coating is possible is limited. The longer the time, the better, but preferably at least 3 to 6 hours. Also, after coating film formation,
A cured coating film is obtained by leaving it as it is and drying it. Drying usually requires 18 to 24 hours, but when the room-temperature curable composition of the present invention is used outdoors in a cold region in winter, it is expected that curing will not sufficiently proceed. For this reason, depending on the coating conditions and the drying conditions of the coating film, in the winter, a highly reactive amine curing agent such as meta-xylene diamine is selected, and by simultaneously using a curing accelerator such as nonylphenol, the curing is performed. It is preferable to adjust the time.

[0024]

EXAMPLES Production Example 1 Modification of Epoxy Resin with Unsaturated Fatty Acid
Production of goods DER 331 (Dow Co. bisphenol A type liquid epoxy resin, epoxy equivalent 189) 100g, L-75
(Nisshin Oil's linseed oil fatty acid, acid value 200, iodine value 177) 147 g, 0.8 g of trimethylbenzylammonium chloride and 50 g of xylene were charged into a 500 ml separable flask equipped with a thermometer, a stirrer and a nitrogen inlet tube, and 120 The reaction was carried out at １５０150 ° C. for 3 hours.
After confirming that the peak based on the epoxy group disappeared in the IR spectrum, the reaction was terminated. After cooling to 60 ° C., the solvent was removed, and the iodine value was 162 and the iodine value was measured by a B-type viscometer.
An epoxy resin-modified unsaturated fatty acid having a viscosity of 2200 cps at ℃ was obtained.

Example 1 Preparation of a room temperature curable composition 47.5 g of DER 331 (a bisphenol A type liquid epoxy resin manufactured by Dow, epoxy equivalent: 189), Production Example 1
Was mixed with 4.8 g of the modified unsaturated fatty acid obtained in the above, 2 g of cobalt naphthenate (metal content 6%), 2 g of manganese naphthenate (metal content 6%), and 15.8 g of xylene. Add 15.8g,
A curable composition having a nonvolatile content of 81% was obtained.

Comparative Example 1 No modified unsaturated fatty acid
Preparation of a Room Temperature Curable Composition A curable composition having a nonvolatile content of 80% was obtained in the same manner as in Example 1 except that the modified unsaturated fatty acid was not used. Comparative Example 2 A curing accelerator containing no modified unsaturated fatty acid was used.
A cold-curable composition having a non-volatile content of 81% was obtained in the same manner as in Comparative Example 1 except that 5% by weight of nonylphenol as a curing accelerator was added to DER331.

Evaluation of Curable Composition <Curability> A coating film was formed on a glass plate using a 6 mil doctor blade for the curable compositions obtained in Example 1 and Comparative Examples 1 and 2. The curability of this coating film at 5 ° C. was evaluated over time based on the following criteria. ：: No dent is generated even when pressed strongly with a finger, and it feels firm. △: No dent is generated when pressed with a finger, but it is felt soft. ×: A dent is generated when pressed with a finger. <Workability> Prepare curable composition After this, the change in viscosity was measured with a B-type viscometer. If it is 4000 cps or less,
It can be said that the workability is good. Table 1 shows the results.

[0028]

[Table 1]

With the room temperature curable composition of the present invention, satisfactory results were obtained in both curability and workability. On the other hand, in Comparative Example 1 containing no unsaturated fatty acid modified product of the epoxy resin, the curability was insufficient, and in Comparative Example 2 in which a curing accelerator was added to supplement the curability, there was a problem in workability. Was.

[0030]

EFFECTS OF THE INVENTION The room temperature curable composition of the present invention can achieve a good balance between application time and curability while having a high solid content. This is because the unsaturated fatty acid-modified product of the liquid epoxy resin contained in the composition of the present invention dilutes the reaction between the epoxy resin and the amine curing agent, and moderately suppresses the curing reaction rate. It is considered that the curing reaction of the unsaturated bond is progressing. Since the room-temperature-curable composition of the present invention has the above properties, it is effective to be used as a paint applied to a structure composed of concrete, steel plate, and steel frame.

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Claims (4)

[Claims] A cold-setting composition comprising an epoxy resin, an amine curing agent, a modified unsaturated fatty acid of a liquid epoxy resin, and a dryer, wherein the solid content of the modified unsaturated fatty acid is less than that of the epoxy resin. A room temperature curable composition characterized by being 5 to 20% based on the weight of the solid content. 2. The unsaturated fatty acid used for producing the modified unsaturated fatty acid has an acid value of 175 to 205 and an iodine value of 1
The cold-setting composition according to claim 1, wherein the composition is 20 to 205. 3. The modified unsaturated fatty acid has a modification rate of 90%.
The cold-setting composition according to claim 1 or 2, which is the above. 4. A pigment having a volume pigment concentration of 25 to 45% and a viscosity at 25 ° C. of 1000 to 2000 c.
The cold-setting composition according to any one of claims 1 to 3, wherein a nonvolatile content when adjusted to ps is 75% or more.