JPS60219267A - Rust-preventing coating composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which is of an energetic ray-curable type and gives a coating film having excellent resistance to water, moisture and corrosion and alkaline removability, consisting of a specified energetic ray- curable component, a copolymer and a phenolic resin. CONSTITUTION:30-90wt% energetic ray-curable component (A) consisting of a polymerizable compd. contg. at least one (meth)acryloyl group per molecule [e.g. butyl (meth)acrylate] and optionally a polymerizable compd. contg. at least one vinyl group per molecule [e.g. (alpha-methyl)styrene], 5-40wt% copolymer (B) having an MW of 10,000 or below and an acid value of 50-500 and polymerizable with component A, obtd. from a styrene compd. (e.g. styrene or its nuclear substitution compd.) and an unsaturated dicarboxylic acid (anhydride) or its partial ester compd., and 5-30wt% phenolic resin (C) are blended together. The resulting compsn. is applied to a substrate such as steel stock by means of spray coating, etc. to form a rust-preventing film of 5-50mum in thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an active energy ray-curable coating composition that provides excellent rust prevention properties to steel materials and forms a protective film that has excellent alkali removability.

Some base materials such as steel materials are coated for the purpose of protection during the period from manufacture to processing. The protective coating is then removed during processing or use. Conventionally, such protection has been achieved by applying anti-rust oils made of mineral oil, animal and vegetable oils, or water-soluble anti-corrosive agents, but these coating solutions take time to dry and also pose a problem for the working environment. There is a drawback that it does. Therefore, it has been desired to develop a paint or a coating method that takes a short drying time and can maintain a good working environment.

A method that is currently attracting attention as a means to meet such demands is a coating film forming method using active energy rays such as ultraviolet rays or electron beams. This method not only takes an extremely short time to cure the coating film-forming components, but also has the characteristics that the coating components used are composed of high-boiling point, low-volatility curable components, allowing the work environment to be maintained in a good condition. have. The present invention provides a paint that can be applied to such a coating method.

As mentioned above, the protective coating coated on steel materials is removed during processing or use, but its removal is usually done with an alkaline aqueous solution, and sodium hydroxide, sodium orthosilicate, sodium metasilicate, etc. used. In order to improve the film removal performance of protective coating films using such aqueous alkaline solutions, it is possible to introduce functional groups that easily react with alkaline substances into the coating film components.
For example, JP-A-52-38433 and JP-A-53
Publication No. 74533 discloses paints containing a polymer having a carboxyl group in the coating film-forming components.

Generally, the weaker the alkaline aqueous solution used for removing the protective coating film of steel materials, etc., the better. Therefore, it is desirable to introduce more carboxyl groups into the coating film components.

However, on the other hand, the more carboxyl groups are introduced, the lower the water resistance, corrosion resistance, etc. of the paint film, and the more the carboxyl group is introduced into the paint film components, the more the performance of the paint film, such as water resistance and corrosion resistance, decreases. The amount of carboxyl groups that can be added is naturally limited.

In addition, if the polymer used to introduce carboxyl groups into the coating film component is a high molecular weight material, the viscosity of the paint will increase and the workability of painting will be impaired. The amount of carboxyl group introduced is limited.

In order to alleviate these limitations, various efforts have been made, such as using polymerizable monomers and oligomers that have carboxyl groups in their molecules in paint components, but in any case, the desired amount of It has been difficult to obtain a paint component that can simultaneously satisfy water resistance, humidity resistance, corrosion resistance, and alkali removability by introducing a carboxyl group.

As a result of various studies in view of the current situation, the present inventors have found that by combining a specific copolymer having a carboxyl group in the molecule and a phenol resin with an active energy ray-curable component, It has been found that it is possible to obtain an active energy ray-curable antirust coating composition that provides a coating film with excellent water resistance, moisture resistance, corrosion resistance, and good alkali removability.

That is, the present invention provides an active energy ray-curable component consisting of (P) a polymerizable compound having one or more (meth)acryloyl groups in the molecule, (υ styrene compound and unsaturated dicarboxylic acid or its anhydride). or a partially esterified product thereof and a copolymer derived from the copolymer and (C) a phenol resin.

The coating film obtained by curing with active energy rays using the coating composition of the present invention has extremely good water resistance, moisture resistance, and corrosion resistance, and also has extremely good alkaline removability. It has the characteristics of It can be understood that this effect is brought about synergistically by the combined use of component (b) and component (C), and the introduction of only carboxyl groups, which has been proposed in the past, has improved rust prevention and alkaline properties. Considering that this was a problem that was difficult to solve due to requirements that conflict with film removability, it can be said that the present invention has great practical significance.

Components (axis), (b), and (C) constituting the coating composition of the present invention will be explained below. In the description of this specification, "(meth)acryloyl group" includes an acryloyl group and a methacryloyl group. is an expression, as well as
(Meth)acrylic acid consists of acrylic acid and methacrylic acid.
(Meth)acrylate is used as an expression that includes acrylate and methacrylate, respectively.

The "active energy ray-curable component consisting of (a) a polymerizable compound having one or more (meth)acryloyl groups in the molecule" used in the coating composition of the present invention is a known polymerizable component per se. Here, the term "polymerizable compound having one or more (meth)acryloyl groups in the molecule" refers to monomers, oligomers, and polymers,
Furthermore, mixtures thereof are also included. Specific examples of "polymerizable compounds having one or more (meth)acryloyl groups in the molecule" include butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, ) acrylate, benzyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate
Acrylate, phenyloxyethyl (meth)acrylate, 2-(2-(ethyloxy)ethyloxy)ethyl (meth)acrylate, dihydrocyclobentadienyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (Meth)7!J/14 esters represented by (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, 2-hydroxy-3-butyloxypropyl (meth)acrylate, etc.; ethylene Glycol di(meth)acrylate, brobylene glycol di(
meth)acrylate, diethylene glycol di(meth)
Acrylate, dibrobylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, trimethylolpropane triacrylate Polyol poly(meth)acrylates represented by (meth)acrylate, neobentyl glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(,meth)acrylate, etc. or polyhydric carboxylic acid and hydroxyl group-containing (meth)
Reaction products with acrylic compounds (e.g., 2-hydroxyethyl (meth)acrylate, N-methylol (meth)acrylamide, etc.) or epoxy group-containing (meth)acrylic compounds (e.g., glycidyl (meth)acrylate, etc.) ;Urethane (meth)acrylates obtained by reacting an organic isocyanate compound (for example, hexamethylene diisocyanate, phenyl isocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, etc.) with a hydroxyl group-containing (meth)acrylic compound;A polyepoxy compound and ( Addition reaction product with meth)acrylic acid: A reaction product between a low molecular weight or high molecular weight polyester resin having a hydroxyl group in the molecule and (meth)acrylic acid, or a low molecular weight or high molecular weight polyester resin having a carboxyl group in the molecule. Polyester (meth)acrylates which are reaction products of polyester resin and hydroxyl group-containing (meth)acrylic compound; Epoxy (meth)acrylates obtained by reacting (meth)' with acrylic acid; polyurethanes obtained by reacting a low molecular weight urethane resin having an isocyanate group in the molecule with a (meth)acrylic compound containing a hydroxyl group (Meth)acrylates; (meth)acrylamide, N-methylol (meth)acrylamide, N
Examples include (meth)acrylic acid amides such as -butyloxymethyl (meth)acrylamide.

These compounds are just examples, and it goes without saying that any compound having one or more (meth)acryloyl groups in its molecule that can be polymerized by active energy rays can be used in the coating composition of the present invention. be.

If desired, a "polymerizable compound having one or more vinyl groups in the molecule" may be added to the active energy ray-curable component of the coating composition of the present invention. I can do it. Such a compound is a compound that can be polymerized by active energy rays and can be copolymerized with a polymerizable compound having one or more (meth)acryloyl groups in the molecule, and specifically, styrene, Styrene compounds exemplified by α-methylstyrene, p-tertiary butylene, etc.; vinyl acetate, vinyl propionate, vinyl butyrate, vinyl lauronate, peobium (trade name), vinyl benzoate, vinyl salicylate, succinate Vinyl esters exemplified by divinyl acid and divinyl adipate; divinylbenzene;
N-vinylpyrrolidone: 4-vinylpyridine; Furthermore, allyl compounds exemplified by diallyl phthalate, triallyl cyanurate, etc.; unsaturated polycarboxylic acids exemplified by maleic esters, fumaric esters, itafonic esters, etc. Examples include esters.

Next, "(b) a copolymer derived from a styrene compound and an unsaturated dicarboxylic acid, an anhydride thereof, or a partial ester thereof" used in the coating composition of the present invention refers to styrene or a nuclear substituted derivative thereof. and unsaturated dicarboxylic acids represented by maleic acid, fumaric acid, itaconic acid, and citraconic acid, or unsaturated dicarboxylic acid anhydrides represented by maleic anhydride and citraconic anhydride, or monomers of the above unsaturated dicarboxylic acids. This refers to a copolymer derived from ester, etc., and the copolymer has carboxyl groups and/or acid anhydride groups in the molecule that can be easily removed when the coating film is treated with an alkaline aqueous solution. Must be included. Usually, a copolymer having an acid value of 50 to 500 is used, and a copolymer having a molecular value of 10,000 or less, preferably 1,000 to 50,000 is selected. Such a copolymer is commercially available, for example, under the trade name "rSMA resin" and is easily available.

Furthermore, "(C) phenolic resin" used in the coating composition of the present invention refers to a known resin obtained by subjecting phenol or alkylphenol to formaldehyde in the presence of an acidic or basic catalyst through an addition condensation reaction. This phenolic resin may be a so-called novolac type or a resol type, and may also be a modified phenolic resin such as a rosin-modified phenolic resin.

These phenolic resins have a softening point of 60° C. or higher from the viewpoint of coating film performance.

The blending ratio of each component constituting the coating composition of the present invention is as follows. That is, in 100 parts by weight of the total composition, the component (a) is 30 to 90 parts by weight, the component (b) is 5 to 40 parts by weight, and the component (c) is 5 to 30 parts by weight. It is sufficient if they are selected and blended so that it accounts for 1 person. (b) Component (C) The lower limit of the amount of component (C) is determined by taking into account its contribution to alkaline film removability. This was determined in consideration of the deterioration of the coating film's properties such as durability, moisture resistance, and corrosion resistance.

The coating composition of the present invention may optionally include natural resins such as rosin, 7-rank, etc.; alkyd resins, unsaturated polyester resins, xylene resins, petroleum resins, Synthetic resins such as epoxy resins, polyurethanes, acrylic polymers, vinyl polymers, and cellulose derivatives; pigments; and other additives may be appropriately selected and added. Furthermore, from the viewpoint of painting workability, an organic solvent is sometimes added as a viscosity modifier to the paint.

The coating composition of the present invention also includes (a) as the component (a).
Since the composition contains a polymerizable compound having a meth)acryloyl group, it is desirable to add a polymerization inhibitor to the composition. As the polymerization inhibitor used, any known compound may be used, such as hydroquinones such as hydroquinone, methylhydroquinone, and tertiary-butylhydroquinone; p-methoxyphenol, 2,6-dibutyl-butyl- Phenols such as 4-methylphenol; Quinones such as benzoquinone and diphenylbenzoquinone; Catechol; Pyrogallol;
Examples include Fe/-f-azine; N,N'-diphenyl-p-phenylenediamine; copper salts and the like.

In curing the coating composition of the present invention, active energy rays such as ultraviolet rays, electron beams, X-rays, and r-rays are used, and among them, ultraviolet rays or electron beams are more preferably used. When using ultraviolet rays, it is desirable to add a sensitizer to shorten the irradiation time and improve irradiation efficiency. As the sensitizer, conventionally used compounds may be used, and of course, so-called known photoinitiators are also included.

In applying the coating composition of the present invention to a base material such as steel, a commonly used coating method such as a spray method or a roll coater method may be used, and the amount of application should be determined according to the required rust prevention performance. Alternatively, although it is difficult to determine it unconditionally depending on the film removal performance, etc., it is usually selected so that the coating film thickness is from several micrometers to several tens of micrometers, preferably about 5 to 50 micrometers.

- Hereinafter, the compositions of the present invention will be specifically explained with reference to Examples and Comparative Examples. In the following description, parts are based on weight.

Test plates for coating film performance tests in Examples and Comparative Examples were prepared in the following manner. That is, 5 parts by weight of pesozoin isobutyl ether as a sensitizer was added to 100 parts by weight of the coating composition.
After adding parts by weight and dissolving it uniformly, 20%
It was coated with a wire rod to a film thickness of μm. Next, the coated test plate was passed on a conveyor at 8 cIIL directly below a diffused high-pressure mercury lamp with an output of 80 watts/aR for an effective irradiation time of 6 seconds to produce a test plate with a cured coating film.

Using this test board, performance tests were conducted on the following items.

[Vocal membrane performance evaluation method]

t Adhesion 100 goblets of 81 cm width were made, a peel test was performed using cellophane tape, and the number of goblets remaining was expressed.

2. Pencil hardness: Evaluated using a pencil hardness tester.

& Corrosion resistance: A test (72 hours) was conducted using a salt sobre tester. The state of rust and blistering was evaluated on a five-point scale.

○...The area where rust and blisters occur is a few percent or less Δ~○...The area where rust and blisters occur is a few percent~2096 △...The area where rust and blisters occur is between 2096 and 4096 X~△... - The area where rust and blisters occur is 40% to 60% × -- The area where rust and blisters occur is 6096 or more 4. Moisture resistance: Tested (72 hours) using a humidity tester. The state of rust and blistering was evaluated on a five-point scale.

(Evaluation is based on the corrosion resistance test.) 5. Film removability The film was immersed in an aqueous solution of sodium 3-orthosilicate at 0°C for 30 minutes, and the film was evaluated for film removal or dissolved state.

○...Film removal or dissolution △...Film removability or lack of work ×...Film removability Example 1 and Comparative Examples 1 and 2 Component (a) specified in the present invention as a paint composition, (b) )J
QJ and component (c) were blended in the proportions shown in Table 1.

A monofunctional acrylic monomer (acid value of 1 or less) sold by Toagosei Kagaku Kogyo Co., Ltd. under the trade name 1 Reloex M-5700 was used as the cryointestinal, and as the component (b), ARCO Partial esterification of styrene-maleic acid copolymer rSMA-1440AJ (molecular weight 2500, acid value 175) manufactured by Co., Ltd. was used, and as the component (c), product name rPSK-222 from Gunei Chemical Industry Co., Ltd. was used.
A novolac type phenol resin (softening point: 88°C) sold as "No. 5" was used.

For comparison, a coating composition in which component (d) was not used and component (b) was increased (Comparative Example 1) and mono(2-acryloyl orthophthalate), which is an acrylic monomer having a carboxyl group, as a polymerizable component. oxyethyl) ester (
A coating composition (comparative example 2) using AEP (abbreviated as AEP) was similarly tested.

The results are shown in Table 1.

Table 1 Example 2 and Comparative Examples 3 and 4 For the coating composition, a monofunctional acrylic monomer sold under the trade name [P-200AJ by Kyoeisha Yushi Kagaku Kogyo O] was used as the component (a) specified in the present invention. death,
As the component (b), a styrene-maleic anhydride copolymer "SMA-1 o o o AJ (molecular weight 1600, acid value 480) manufactured by ARCO of the United States was used, and as the component (C) a novolac type manufactured by Gunei Chemical Industry Co., Ltd. A phenol resin (trade name "PSK-4300", softening point 95°C) was used and blended in the proportions shown in Table 2.

For comparison, similar tests were conducted on coating compositions that did not use component (C) (Comparative Examples 3 and 4).

The results are shown in Table 2.

Example 3 and Comparative Example 5 The coating composition contained tetrahydrofurfuryl acrylate (abbreviated as THF-A) and brocade opentyl glycol diacrylate (NP) as the component (a) specified in the present invention.
(abbreviated as C-A), and rice ARC as the (b) component.
Styrene-maleic anhydride copolymer rSMA- manufactured by O Company
rPSK-2000AJ (molecular weight 1700, acid value 350) used in Example 1 as component (C).
2225J was used, and each was blended in the proportions shown in Table 2.

For comparison, a similar test was conducted on a coating composition that did not use component (C) (Comparative Example 5).

The results are shown in Table 2.

Example 4 The coating composition was composed of "Aloex M-57-00J used in Example 1 as component (a) specified in the present invention, rTHF-'AJ used in Example 6, and 1,6-hexanediol. diacrylate (abbreviated as HDDA), and as the component (b), a styrene-maleic acid copolymer) esterified product rSMA-3840AJ manufactured by ARCO, Inc.
(Bun-jin 2300, acid value 1o5) was used, and (as the d component, an alkylphenol resin manufactured by Hitachi Chemical Co., Ltd.) was used.
Product name: “Hitanol 20834, Softening point: 75-95
℃) and were blended in the proportions shown in Table 2.

The results are shown in Table 2.

Example 5 As for the paint composition, "Aroex M-5700J" used in Example 1 as the axis component specified in the present invention, rP-200AJ used in Example 2, and "Aroex M-5700J" used in Example 2, and "Alo A polyfunctional acrylate (acid value 6o or less) sold as X M-8050J was used, and rsMA-1 used in Example 1 was used as the component (b).
440A'' and rPSK-2225J used in Example 1 as component (C), 11. Each was blended in the proportions shown in Table 2.

The results are shown in Table 2.

Claims (1)

[Claims] G) an active energy ray-curable component consisting of a polymerizable compound having one or more (meth)acryloyl groups in the molecule; (b) a styrene compound and an unsaturated dicarboxylic acid or its anhydride or its partially esterified product; A rust-preventive coating composition containing a copolymer derived from the above and (C) a phenol resin.