JPH0433825B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides the following methods: by irradiation with high-energy radiation,
This relates to a temporary rust preventive agent that forms a rust preventive coating on metal. Damage during storage and handling of metal materials such as steel pipes,
Mineral oil, air-drying modified vegetable oils (eg, alkyd resins), and other water-soluble organic substances have conventionally been used as temporary rust preventive agents to prevent rust and maintain quality. However, these
In most cases, the paint film dries slowly or does not dry at all, causing rust preventive agents to drip or run off, skid marks caused by conveyor rolls, sticking at contact points after packaging, and film peeling off when unpacking. Therefore, the anti-corrosion effect was insufficient, causing a decrease in commercial value. In addition, contamination of the working environment due to volatilization and dripping of the contained solvent has also been a problem. In view of these circumstances, a high-energy radiation-curable paint that can dry in a short time was considered as a way to solve the above problems, but conventional radiation-curable paints have poor adhesion to metals and It has disadvantages such as poor flexibility and difficulty in removing the film with an alkaline aqueous solution when a rust preventive film is no longer necessary. The present invention was developed in consideration of the above circumstances, and has a fast curing speed and a coating film after curing.
The object of the present invention is to provide a radiation-curable temporary rust preventive agent that is highly flexible, has excellent adhesion to metals, and is easy to remove with an alkaline aqueous solution. In order to achieve this objective, in the present invention, a polymerizable unsaturated resin is modified with a polymerized fatty acid to impart flexibility, and due to the strong lipophilicity of the polymerized fatty acid, it can be completely degreased. It wets well even on untreated metal surfaces and does not reduce adhesion. Further, alkaline film removability is imparted by blending a carboxyl group-containing reactant of hydroxyalkyl (meth)acrylate and polybasic acid and/or its anhydride. Furthermore, by blending 2-hydroxyethyl (meth)acroyl phosphate, adhesion and rust prevention properties are improved. Furthermore, curability and workability are adjusted by blending tetrahydrofurfuryl (meth)acrylate and a compound having two or more (meth)acryloyl groups in one molecule. It is necessary to pay attention to the blending ratio of each of the above-mentioned components in order to balance the performance as a temporary rust preventive agent and make it practical. In this specification, the (meth)acryloyl group includes both an acryloyl group and a methacryloyl group. Similarly, (meth)acrylate includes both acrylate and methacrylate. Therefore, the temporary rust preventive agent of the present invention contains polymerized fatty acids.
For 100 parts by weight of a polymerizable unsaturated resin (hereinafter referred to as [component A]) containing 10 to 50% by weight and having two or more (meth)acryloyl groups per molecule,
10 to 50 parts by weight of a reactant of hydroxyalkyl (meth)acrylate and a polybasic acid and/or its anhydride (hereinafter referred to as [component B]), 2-hydroxyethyl (meth)acryloyl phosphate (hereinafter referred to as [component B]), 0.5 to 10 parts by weight of [component C]), 10 to 80 parts by weight of tetrahydrofurfuryl (meth)acrylate (hereinafter referred to as component D), (meth)
5 polymerizable unsaturated compounds having two or more acryloyl groups in one molecule (hereinafter referred to as [component E])
It is made by mixing ~40 parts by weight and has an acid value of 20 to 100. Specific examples of component A used in the present invention include epoxy (meth)acrylates, urethane (meth)acrylates modified with 10 to 50% by weight of polymerized fatty acids, and having two or more (meth)acryloyl groups in one molecule. ) acrylate, polyester (meth)acrylate, etc., which can be heated at room temperature to 300°C.
It is easily synthesized by a conventional method using an esterification reaction or a urethanization reaction in the temperature range of °C. The polymerized fatty acids used here are carboxylic acids obtained by polymerizing fatty acids such as linseed oil fatty acids, dehydrated castor oil fatty acids, safflower fatty acids, soybean fatty acids, and tall oil fatty acids, and are mainly composed of dimers. However, it also includes monomers and trimers. When the amount of polymerized fatty acid in component A exceeds 50% by weight, curability decreases and coating film hardness becomes poor. If it is less than 10% by weight, the flexibility of the coating film will decrease and the adhesion will be poor. Next, component B is hydroxyalkyl (meth)
By adding a polymerization inhibitor and a basic catalyst or an acidic catalyst to cause an esterification reaction between an acrylate and a polybasic acid and/or its anhydride at a temperature of room temperature to 150°C, preferably 50 to 120°C. , easily obtained. Each component used in the synthesis of component B will be exemplified.
Examples of the hydroxyalkyl (meth)acrylate include 2-hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate. In addition, as polybasic acids and/or their anhydrides, maleic acid, maleic anhydride,
Examples include fumaric acid, succinic acid, succinic anhydride, adipic acid, sebacic acid, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, etc. . When the amount of component B exceeds 50 parts by weight, the viscosity becomes high, which not only deteriorates workability but also reduces water resistance. Moreover, if it is less than 10 parts by weight, the alkali film removability will decrease. Component C is 2-hydroxyethyl (meth)acryloyl phosphate, and if it exceeds 10 parts by weight, it will have poor compatibility with component A, and the rust inhibitor may become cloudy or separate. . Moreover, if it is less than 0.5 part by weight, the adhesion and rust prevention properties will decrease. Component D is tetrahydrofurfuryl (meth)acrylate, and if it exceeds 80 parts by weight, the curability and alkali removability will decrease. Moreover, if it is less than 10 parts by weight, workability and adhesion will decrease. Component E is a polymerizable unsaturated compound having two or more (meth)acryloyl groups in one molecule, and is usually called a reactive diluent and has a relatively low molecular weight and low viscosity. For example, ethylene glycol,
Di(meth)acrylates such as diethylene glycol, polyethylene glycol, neopentyl glycol, 1,6-hexanediol, tri(meth)acrylates such as trimethylolpropane, pentaerythritol, dipentaerythritol hexa(meth)acrylate and polyester poly(meth)acrylates ) acrylate, etc.
If the amount of component E exceeds 40 parts by weight, the adhesion and alkali removability will decrease, and if it is less than 5 parts by weight, the curability will decrease. As mentioned above, a product with an acid value of 20
~100 radiation-curable temporary rust inhibitors have excellent workability and cure quickly by irradiating with high-energy radiation, and the cured coating film has flexibility, adhesion, rust prevention, and alkali properties. It was found that the film had excellent film removability. In the present invention, the acid value of the radiation-curable temporary rust preventive agent is limited to 20 to 100 because if the acid value exceeds 100, the water resistance will decrease, and if the acid value is less than 20, the alkaline film removability will be poor. It is. As a source of high-energy radiation, it is convenient to use an ultraviolet generator such as a high-pressure mercury lamp or a metal halide lamp, but an electron beam accelerator or the like can also be used. When using ultraviolet rays as radiation, benzoin, ethers of benzoin and alkyl such as methyl, ethyl, propyl, butyl, benzophenone, benzyl, benzyl dimethyl ketal, methyl orthobenzoin benzoate, chlorothioxanthone, 2,2'-dimethyl Ethoxyacetophenone, 2-methylthioxanthone,
Known photosensitizers such as 2,2'-diethoxybenzophenone and 2-ethylanthraquinone can be added as appropriate. Furthermore, pigments and various additives can be added as necessary. The metal materials to be coated with the rust preventive of the present invention include:
It can be applied to metals such as iron, carbon steel, stainless steel, copper, zinc, tin, aluminum, their alloys, plating materials made of them, etc., and the shape can be plate,
It can be applied to wires, rods, tubes, and various other molded materials. All painting methods such as ironing, spraying, showering, coating, and rolling can be used. The following will be explained in detail based on examples. A component: Into the four-necked flask of 1, add Epototo YD-
128 (manufactured by Toto Kasei Co., Ltd., epoxy resin (epoxy equivalent: 184 to 194)) 570 g, Versadime 216 (manufactured by Henkel Japan Co., Ltd. dimer acid, acid value 174) 280 g, acrylic acid 144 g, hydroquinone 1 g and triethylamine 4 g were prepared, and the mixture was heated at 110°C. The reaction was carried out for 10 hours to obtain a polymerized fatty acid-modified epoxy acrylate resin (reactant A-1) having an acid value of 2. 300 g of 2,4-tolylene diisocyanate and 0.3 g of dibutyltin dilaurate were placed in a four-necked flask from Step 1, and the mixture was heated for 50 g in a nitrogen gas stream.
Heat to ℃. 2-hydroxyethyl acrylate in which 0.5 g of hydroquinone was dissolved was added dropwise over 3 hours, and the mixture was reacted at the same temperature for 4 hours to obtain a reaction product with an isocyanate group content of 13.8%. Also, separately, the same type of device, Versa Dime 216 and 280
g, phthalic anhydride 74 g, ethylene glycol 31
g, neopentyl glycol, 53 g, and trimethylolpropane, 67 g, attached a water drain pipe with a partial condenser, heated to 220°C in a stream of nitrogen gas for 2 hours, and further reacted at that temperature for 3 hours to remove the acid. The value was set to 3. After cooling to 100°C, 290 g of the above reactant was added dropwise over 2 hours, and the reaction was continued at the same temperature for 4 hours. The isocyanate group with an infrared absorption spectrum of 2260/cm disappeared, resulting in a modified polymerized fatty acid with an acid value of 2. A urethane acrylate resin (reactant A-2) was obtained. Comparative example of component A: Into the four-necked flask of 1, add Epototo YD-
380g of 128, 144g of acrylic acid, hydroquinone
Prepare 0.5g and 2g of triethylamine, 110
The reaction was carried out at ℃ for 10 hours to obtain an epoxy acrylate resin having an acid value of 3 (reactant A-3). Component B 348 g of 2-hydroxyethyl acrylate, 0.4 g of hydroquinone, and 0.8 g of triethylamine are placed in the four-necked flask of 1, and the temperature is raised to 100°C. Next, at the same temperature, 456 g of tetrahydrophthalic anhydride was divided into four portions and charged every 30 minutes, and the reaction was continued for an additional 4 hours to obtain a reactant (reactant B-1) with an acid value of 210. 464 g of 2-hydroxyethyl acrylate, 0.4 g of hydroquinone, and 0.8 g of triethylamine were placed in a four-necked flask in Step 1, and the temperature was raised to 100°C. Next, at the same temperature, pyromellitic anhydride
Divide 436g into 4 portions and prepare them every 30 minutes.
The reaction was continued for an hour, and a reactant with an acid value of 250 (reactant B
-2) was obtained. Blend recipe Table 1 shows the blend recipe of Examples and Comparative Examples. Note that the numerical values in the table indicate parts by weight.

[Table] Using the radiation-curing temporary rust preventive agent obtained from the above formulation, a 70 x 150 x 0.8 mm polished mild steel plate (JIS G-3141) was coated with a bar coater and coated with a high-pressure mercury lamp (120W/ cm), and the resulting coating film was tested by irradiating it with ultraviolet light for 1 second from a distance of 10 cm. The test items are as follows. Pencil hardness: Based on JIS K-5400 6-14. Impact resistance: Compliant with JIS K-5400 6-13. (○
Adhesion: A 10 mm square, 1 mm wide base was peeled off with cellophane tape and its condition was observed. (○ indicates no abnormality,
△ indicates partial peeling, × indicates complete peeling) Alkaline film removal property: 80% in 5% caustic soda aqueous solution
It was immersed at ℃ for 15 minutes and the state of film removal was observed. (○: completely removed, △: partially removed, ×: not removed) Salt spray resistance: A cross cut was inserted and the width of the rust was measured after 72 hours. Moisture resistance: The state of the blister after 72 hours,
Observation was made using the ASTM method. The test results are shown in Table-2.

[Table] As is clear from this test result, the radiation-curable temporary rust inhibitor of the example of the present invention showed good results in all tests, whereas the comparative example showed good results in all tests. It showed insufficient performance in two or more test items and was unsuitable as a radiation-curable temporary rust inhibitor. Therefore, the radiation-curable temporary rust inhibitor of the present invention is
It has excellent coating hardness, impact resistance, adhesion, and rust prevention, and is easy to remove with an alkaline aqueous solution, making it extremely suitable for temporary storage of metal materials.

Claims (1)

[Claims] 1. For 100 parts by weight of a polymerizable unsaturated resin containing 10 to 50% by weight of polymerized fatty acids and having two or more (meth)acryloyl groups in one molecule, hydroxyalkyl (meth)acrylate, polybasic acid and/or
or 10 to 50 parts by weight of the reactant with its anhydride, 0.5 to 10 parts by weight of 2-hydroxyethyl (meth)acryloyl phosphate, 10 to 80 parts by weight of tetrahydrofurfuryl (meth)acrylate, and 1 part by weight of (meth)acryloyl group. An acid value of 20 to 40 parts by weight of a polymerizable unsaturated compound having two or more in the molecule.
100 radiation curable temporary rust inhibitor.