JPS63258969A - Surface coating composition for metallic material - Google Patents

Abstract

PURPOSE:To obtain the titled composition, containing an aqueous emulsion having a specific particle diameter or below and crosslinked structure as an essential component and capable of forming resin films having excellent transparency, glossiness, smoothness, water, solvent resistance, etc., on metallic material surfaces without causing cracking and peeling. CONSTITUTION:The aimed composition containing an aqueous emulsion having <=100nm average particle diameter and crosslinked structure and preferably a lower glass transition point than a value calculated by a weight fraction method as an essential component. The resultant films have excellent mechanical strength, such as hardness, tensile strength and modulus strength.

Description

[Detailed Description of the Invention] [Technical Field] The present invention is applicable to general steel buildings, such as internal and external walls of tanks, chemical plants, bridges, steel towers, etc., which are particularly corrosive and require so-called heavy anti-corrosion coating. Steel products such as roofs and interior and exterior walls of buildings that require anti-rust paint, as well as water supply, sewage, water supply, oil transfer pipes, coal/oil mixtures (COM)
The present invention relates to a surface coating composition for metal materials that is suitably used for lining the inner and outer surfaces of steel pipes such as seamless pipes for transportation.

[Prior art]

Generally, rust-preventing paints made of lead compounds or zinc powder and colorants are known as rust-preventing and corrosion-preventing methods for metal materials.

Since this anti-rust paint is solvent-based, it poses problems such as the danger of flames and human safety, and also has drawbacks such as poor weather resistance, chemical resistance, abrasion resistance, and durability.

In order to improve these drawbacks, methods have been developed that use cement mortar as a surface coating composition.

Although this product is water-curable, it does not use solvents like anti-corrosion paints, so it is non-polluting.Moreover, due to the strong alkaline atmosphere of cement, there may be some water or dirt on the surface of the metal material. Although it has the advantage of being able to be directly coated with cement, its essential drawback is that cracks occur as the cement hardens and shrinks, and that various properties such as mechanical strength, impact resistance, abrasion resistance, acid resistance, etc. This includes the problem that it is inferior to As a method for modifying the performance of these cement mortars, a so-called polymer cement mortar has been proposed, in which a synthetic resin emulsion such as polyvinyl acetate, polyacrylic acid ester, or vinyl chloride is used as an admixture and mixed with cent mortar. (Unexamined Japanese Patent Publication No. 50-44)
(See Japanese Patent Publication No. 221, Japanese Patent Publication No. 47-38527, Japanese Patent Application Laid-open No. 128543-1983, etc.).

Although this polymer cement mortar seems to be effective in improving various defects of conventional cement mortar,
Performances such as water resistance, salt water resistance, weather resistance, and impact resistance are still not sufficient, and the gloss and smoothness are also poor, so when these surface coatings are applied, It also has the disadvantage that the glossiness is impaired.

〔the purpose〕

An object of the present invention is to provide a surface coating composition for metal materials that has excellent transparency, smoothness, gloss, water resistance, weather resistance, and mechanical properties, unlike conventional surface coating compositions.

[Structure] According to the present invention, an essential component is an aqueous emulsion having an average particle diameter of loOnm or less, a crosslinked structure, and preferably a glass transition temperature lower than the value calculated by the weight fraction method. A surface coating composition for a metal material is provided.

The surface coating composition of the present invention is first required to contain as an essential component an aqueous emulsion whose average particle diameter is 1100 nm or less, preferably 80 nm or less.

In an aqueous emulsion, a film is essentially formed by filling and fusing particles, so the average particle size is required to be small, but in the present invention, as described above, the average particle size is 1001 or less. .

Preferably, it is limited to 80 nm or less, so it has good permeability and can sufficiently wet the minute unevenness of the metal surface, and also has good properties such as heat fusion, film transparency, smoothness, gloss, etc. When the average particle size exceeds 1100 nm, the permeability is insufficient and metal surfaces with minute irregularities cannot be sufficiently wetted. This product may lack penetration into complex shapes, and may also have poor adhesion (density) when the film is formed, resulting in lack of transparency, gloss, and smoothness. The intended purpose of the invention cannot be achieved.

A second feature of the surface coating composition of the present invention is that it has a crosslinked structure within and/or between the particles of the aqueous emulsion.

That is, in the aqueous emulsion of the present invention, within the particles and/or between the particles, for example, the functional groups of the raw material unsaturated monomers, or these and the functional groups of the emulsifier have ionic bonds, hydrogen bonds, condensation reactions, Since it is crosslinked by a polymerization reaction or the like, it is presumed to form a film with excellent transparency, adhesiveness, water resistance, solvent resistance, and mechanical strength.

Further, in the present invention, it is preferable to use an aqueous emulsion having a glass transition temperature lower than the value calculated by the weight fraction method, preferably 3° C. or more, more preferably 5° C. or more lower.

Glass transition temperature (Tg) is the temperature at which a polymer changes from a glassy, hard state to a rubbery state when heated. This glass transition temperature is influenced by various structural factors, and generally has a crosslinked structure. It is known that the glass transition temperature of a polymer increases, and that adding a plasticizer to the polymer lowers the glass transition temperature.

Furthermore, if the glass transition temperature of a component that is a structural factor of a polymer is known, the glass transition temperature of the polymer can be determined from the following equation using the weight fraction method.

Tg TgA TgB WA ; weight fraction wa of component A; weight fraction TgA of component B; glass transition temperature of component A Tgn: glass transition temperature of component B This glass transition temperature is influenced by various structural factors and is generally crosslinked. In the case of polymers with a structure, the glass transition temperature becomes high, and depending on the degree of crosslinking, it may rise by 5 to 7 degrees Celsius, and it is known that adding a plasticizer to the polymer lowers the glass transition temperature. .

On the other hand, for aqueous emulsions, the minimum film-forming temperature is known as the lowest temperature at which a film is formed by filling and fusing particles, and there is a proportional relationship between this minimum film-forming temperature and the glass transition temperature. Conventionally, it has been thought that emulsifiers used to obtain aqueous emulsions cannot lower the minimum film forming temperature or the glass transition temperature of the formed film.

On the other hand, the aqueous emulsion of the present invention exhibits a glass transition temperature lower than the value calculated by the weight fraction method as described above, and therefore, unlike conventional emulsions, it exhibits an excellent plasticizing effect and improves the formation of the film. As the glass transition temperature decreases, the minimum film forming temperature also decreases in proportion to this, making it easy to create films with excellent transparency, adhesiveness, and smoothness even at room temperature, as well as hardness, tensile strength, modulus strength, etc. A film with good mechanical strength can be formed.

In addition, other characteristics of the aqueous emulsion used in the present invention are:
It has excellent dispersion stability over a long period of time.

That is, the aqueous emulsion that is an essential component of the surface coating composition for metal materials used in the present invention has an average particle size of 1100 nm or less, and this emulsion did not pass the forced heating dispersion stability test at 45°C for one week. There is virtually no change in the average particle size even when the particles are used, and even if there is a change, the particle size distribution usually shows a single peak distribution with an average particle size of 1501 or less, and the rate of change is large. Even in cases where the average particle diameter is less than 150 nm, the particle size distribution with the lth number is 97% or more, and the second peak due to particle aggregation is 300 nm.
It shows a two-peak distribution in which the particle size distribution of m or more is an extremely small peak of 3% or less, and the particle size fraction of the average particle diameter is extremely small.

Furthermore, the aqueous emulsion, which is an essential component of the surface coating composition for metal materials used in the present invention, shows an extremely low rate of change in its average particle diameter even when subjected to a long-term storage stability test at 25°C for 6 months. small.

Therefore, in the aqueous emulsion according to the present invention, there is substantially no coalescence of particles with each other over time, and no coarse particles are generated. Since there is no change in viscosity or change in appearance, it shows excellent dispersion stability over a long period of time and has extremely high storage stability.

The reason why the aqueous emulsion, which is an essential component of the surface coating composition for metal materials of the present invention, exhibits excellent dispersion stability as described above is not necessarily clear, but the average particle size of
Because it is less than 0On+e, the Brownian motion between particles is relatively active, and because there is no polymerizable emulsifier remaining in the system and the properties of each particle surface, each particle is sufficiently protected. The basic factor is presumed to be that the particles are prevented from coalescing and aggregating, and the formation of coarse particles is not promoted.

In the present invention, in order to further improve the dispersion stability of the aqueous emulsion, for example, p-hydroxydiphenylamine, N,N'-diphenyldiamine,
Conventionally known polymerization inhibitors and polymerization terminators such as 2,5-di-tert-butylhydroquinone can also be added.

In addition, the average molecular weight of the crosslinked aqueous emulsion, which is an essential component of the surface-coating acid of the metal material of the present invention, is generally more than 100 degrees, often tens of millions to a numerical value, and has a high degree of crosslinking. In some cases, the molecular weight can range from several thousand blades to one billion, and even higher.

The present invention will be explained in more detail below.

The aqueous emulsion, which is an essential component of the surface coating composition for metal materials of the present invention, can be easily obtained by emulsion polymerization of unsaturated monomers.

Examples of this unsaturated monomer include (meth)acrylic esters represented by the following general formula (1) (where R1 and R
2 is hydrogen or a methyl group, R3 is an alkyl group having 1 to 18 carbon atoms), lower fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylonitrile,
Nitriles such as methachronitrile, styrenes such as styrene, α-methylstyrene, and chlorostyrene, vinyls such as vinyl chloride and vinyl bromide, vinylidene chloride,
Examples include vinylidenes such as vinylidene bromide, dienes such as butadiene, chloroprene, and isoprene, and vinylpyridine, and (meth)acrylic acid esters.

Preferably, lower fatty acid vinyl esters and styrenes are used.

In addition, in the present invention, as the unsaturated monomer to be copolymerized with the above-mentioned unsaturated monomer, reactive functional Although unsaturated monomers having groups are preferably used, unsaturated monomers having no reactive functional groups may also be used.

In the emulsion polymerization system, it is also possible to use unsaturated monomers that can be converted into compounds with active hydrogen.

Examples of unsaturated monomers having such reactive functional groups include compounds represented by the following general formulas (II) to (■). These monomers can be used alone or in combination of two or more, and if necessary, other copolymerizable unsaturated monomers can also be used in combination.

R9○H (in the formula, Rt yRz #R4tRs +RG+Rv
+Rs tRs wB+D-E+ tlt t* and t
, is as follows.

R1tR2+; hydrogen atom or methyl group R4; carbon number 2
~4 alkylene group R5; direct bond, alkylene group having 1 to 3 carbon atoms, phenylene group or substituted phenylene group R5; oxygen atom or -NH- R7; hydrogen or alkylol group having 1 to 5 carbon atoms R8;
Hydrogen, an alkylol group having 1 to 5 carbon atoms, or an alkylol group having 1 to 5 carbon atoms
5 alkyl group R5; C1-4 fullkylene group A; methylene group or carbonyl group B - or carboxyl group; hydrogen atom, C1-3 alkyl group, carboxyl group, -CO
N) ICI(CH, or 0OH-CONICONH.

E; hydrogen atom, alkyl group having 1 to 3 carbon atoms or CH,
, C00H tl; real number t2 of 1 to 20; integer 1 of 0 or 1; integer of 0 to 10) General formula (II), (III), (IV), (V), (V
Specific examples of compounds I), (■) and (■) include those shown in Fukishita.

Examples of general formula (n) Glycidyl acrylate Glycidyl methacrylate Glycidyl crotonate Glycidyl allyl ether Examples of general formula (III) Hydroxyethyl acrylate Hydroxyethyl methacrylate Hydroxyethyl crotonate Hydroxyprobyl acrylate Hydroxypropyl methacrylate Hydroxypropyl crotonate Hydroxybutyl acrylate Hydroxybutyl methacrylate polyoxyethylene monoacrylate polyoxyethylene monomethacrylate polyoxyethylene monocrotonate polyoxypropylene monoacrylate polyoxypropylene monomethacrylate polyoxypropylene monocrotonate polyoxybutylene monoacrylate polyoxybutylene monocrotonate hydroxyethyl allyl ether hydroxypropyl Allyl ether hydroxybutyl allyl ether polyoxyethylene allyl ether polyoxypropylene allyl ether polyoxybutylene allyl ether Examples of general formula (IV) Allylamine Acrylamine Methacrylamine Aminostyrene α-Methylaminostyrene General formula (V) Examples Acrylamide Methacrylamide Aminopyrmethacrylamide Monomethylacrylamide Monoethylacrylamide Diethylolaminopyracrylamide General Formula (V
Examples of I) Acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid and its monoester or anhydride of an alkyl group having 1 to 5 carbon atoms, fumaric acid and its monoester or anhydride of an alkyl group having 1 to 5 carbon atoms, maleic acid Alanidofumarate AlanideN-carbamoylmaleic acidamideN-carbamoylfumaric acidamideExample of general formula (■)Methylallylthiolmethylmercapl-styreneExample of general formula (■)N~Methylolacrylic acidamideN-Methylolmethacrylic acidamide N-methylolcrotonic acid amide, N-(2-hydroxyethyl)acrylic acid amide N
-(2-hydroxyethyl)methacrylic acid amide N-(
2-Hydroxypropyl)acrylic acid amide N-(2-
The ratio of the above unsaturated monomer to the unsaturated monomer having a reactive functional group is 99/1 to 60/40 (by weight), preferably 99/1-60/40 (by weight). It is 90/10 (weight). If the usage ratio is greater than 99/1, the degree of crosslinking within and between particles of the aqueous emulsion produced will be small, and if it is less than 60/40, emulsion copolymerizability may be lacking, resulting in the formation of a large amount of aggregates or film formation. The properties may be poor or the film formed may crack. As described above, the emulsifier used when emulsion polymerizing the aqueous emulsion used in the present invention using the above-mentioned unsaturated monomer has an average particle diameter of 1.
Any emulsifier can be used as long as it forms a film having a cross-linked structure and preferably a glass transition temperature lower than the value calculated by the weight fraction method, but particularly preferred emulsifiers include is the following general formula (■
) Polyoxyalkylene ethylenically unsaturated carboxylic acid polyesters (hereinafter abbreviated as poly(meth)acroyl emulsifiers), general formula (X), (X[),
(Xll). Betaine ester emulsifiers represented by (Xm) and (XIV) and general formulas (XV) and (XVI)
and ether carboxylic acid type emulsifiers represented by (X■). (In the formula, R,, R,, R,.tRIL tRtz J1
3, nt4IRIs 1RIG tLt tRll
lai la2 Pal 984 was +as s
at tag 989 Pal. , G, J, L, M, T
.

x, Y, and V are as follows.

R□, 11. ;Hydrogen or methyl group R. ; Alkylene group R11 having 2 to 4 carbon atoms; Alkyl group or alkenyl group having 8 to 30 carbon atoms, which may be linear or branched, preferably having 8 carbon atoms;
~18 R,2; alkylene group having 1 to 5 carbon atoms Rt3. R141R is an alkyl group having 1 to 3 carbon atoms or -C2B40)1, and each may be the same or different.

n1c, n-engineering; an alkyl group having 6 to 20 carbon atoms or hydrogen, at least one of which is an alkyl group having 6 to 20 carbon atoms R18; hydrogen, an alkyl group having 1 to 30 carbon atoms or an alkenyl group a, , a*az la41 as was pa7; indicates the average number of added moles at; a real number from 1 to 50, preferably 8 or more number of moles of alkylene oxide added in the molecule a2; a real number from 0 to 20 as; either Rlg or Lt When one is an alkyl group, use a real number between 0 and 20 as sRL& and R1? When both are alkyl groups, real numbers a from 1 to 30; real numbers a from 1 to 30; real numbers a6 from 0 to 20; real numbers a7 from 0 to 20; real numbers all from 0 to 20; Integer a,; Real number p from 2 to 20; Integer number from 2 to 5 -op-o- 0R, 1 0CnH;
□; Hydrogen or →R0°D■τ11 or -fRl. Ohπ
C=OCR,=CHR.

n; integer from 1 to IO go; integer from 0 to 5 g2; integer from 0 to 10 aza; real number from 1 to 50 (CH3) a-CH-〇- or (CH3)2-Cl1
-o-CH,- and y: real number R22 from 1 to 5? R23; hydrogen or alkyl group having 1 to 20 carbon atoms Y'; alkylene group having 3 to 8 carbon atoms, oxygen or nitrogen to carbonyl group, 〉co-o- or)-〇-L; alkylene having 1 to 5 carbon atoms group or -011-C1(
□ COOM T: Direct bond, oxygen, sulfur ■ Hydrogen or inorganic anion X; Inorganic or organic anion V; Hydrogen or halogen Also, any of these emulsifiers can be used alone,
In particular, we use ultrafine particles of pre-crosslinked polymer latex, which has an ultrafine average particle size, has a dense crosslinked structure within and between particles, and forms a film that exhibits a glass transition temperature lower than the value determined by the calculation formula. In order to obtain the emulsifier used in the emulsion polymerization of the unsaturated monomer, (a) a poly(meth)acroyl type emulsifier represented by the above general formula (IX), (b) the above general formula (X), (XI), (x n
), (Xm), (XIV) betaine ester type emulsifiers and (C) the above general formulas (XV), (XVI)
, an ether carboxylic acid type emulsifier represented by (X■) (a)/(b)=1/9 to 971 or (a)/(c
) J/9-9/1 weight ratio, preferably 1/4-4/1
Used by weight ratio. If this usage ratio is less than 1/9, the degree of crosslinking within and between particles of the aqueous emulsion produced will be small, and if it is greater than 9/1, the average particle diameter of the aqueous emulsion produced may become large.

Further, known anionic, nonionic and cationic surfactants may be added as necessary.

Specific examples include sulfate types of higher alcohols, higher alcohol alkylene oxide adducts, alkylphenol oxide alkylene adducts, and styrenated phenol oxide alkylene adducts, olefin sulfonate types such as α-olefins, and long-chain alkylamine oxide alkylene adducts. and quaternary ammonium salts of di-long-chain alkylamine alkylene oxide adducts, sodium salts of N-(1,2-dicarboxyethyl)-N-octadecylsulfonic acid monoamide, dialkylsulfosuccinates, etc. .

In addition, in obtaining the aqueous emulsion used in the present invention, when using betaine ester as an emulsifier, it is desirable to adjust the pH in the emulsion polymerization step to less than 6, preferably 3-6. This is not preferable because a large amount of aggregates having physical properties significantly different from those of the polymer latex of the present invention are formed in the emulsion polymerization step.

In the present invention, to obtain an aqueous emulsion, a conventionally known emulsion polymerization method can be used as is in the presence of the unsaturated monomer and the emulsifier. For example, in the presence of a polymerization initiator corresponding to 2 O,t-S weights of unsaturated monomers, 10
It may be emulsified and dispersed in water at a concentration of ~60 weight Da to carry out emulsion polymerization.

As the polymerization initiator, water-soluble independent initiators and water-soluble redox initiators used in ordinary emulsion polymerization are used, such as hydrogen peroxide alone or hydrogen peroxide and tartaric acid, citric acid, Combinations with carboxylic acids such as ascorbic acid, hydrogen peroxide, oxalic acid, sulfinic acids and their salts or oxydialdehydes,
In addition to combinations with water-soluble iron salts, persulfates, percarbonates,
Peroxides such as perborates and 2,2'-azobis(2-
amidinopropane) and its salts, 2,2'-azobis(N
, N'-dimethylene-isobutyramidine) and its salts,
Although water-soluble azo initiators such as 4.4'-azobis(4-cyanovaleric acid) and its salts can be used, particularly preferably used polymerization initiators are the above-mentioned water-soluble azo initiators. .

Furthermore, water-soluble nonionic polymeric substances, anionic polymeric substances, cationic polymeric substances, and the like can be used in combination. Furthermore, the plasticizer commonly used in conventional methods, pHal
Stabilizers can also be used in combination if necessary.

Examples of nonionic polymeric substances include polyvinyl alcohol, dextrin, hydroxyethyl starch, starch derivatives such as hydroxyethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and the like.

Examples of anionic polymeric substances include polymers such as anionized hydroxyethyl cellulose, anionized starch, anionized guar gum, anionized chitosan, and carboxymethyl cellulose nil alcohol.

Further, examples of the cationic polymer substance include cationized hydroxyethyl cellulose, cationized starch, cationized guar gum, cationized chitosan, and polymers such as cationic (meth)acrylic acid amide and dimethyldiallylammonium chloride.

These nonionic polymeric substances, anionic polymeric substances, and cationic polymeric substances can be used alone or in combinations of two or more, but the amount added is 0.0000000000000000000000000000000000000000000000000000. 05-5% by weight, preferably 0.1-5% by weight
It is appropriate to use 3% by weight.

Further, as the plasticizer, phthalate ester, phosphate ester, etc. can be used. Furthermore, as a pH1i adjuster, a salt such as sodium carbonate, sodium bicarbonate, or sodium acetate can be used in combination in a range of 0.01 to 3% by weight, but as described above, when a betaine ester type emulsifier is used as an emulsifier. It is desirable to adjust the pH to less than 6.

The surface coating composition of the present invention contains the above-mentioned specific aqueous emulsion as an essential component, but if necessary, rust preventives, anticorrosive agents, aggregates, etc. that are commonly used in this type of composition,
Auxiliary additive components such as extenders, dispersants, wetting agents, water repellents, hydraulic inorganic materials such as cement and mortar (paste), and crosslinking accelerators can be blended.

The surface coating composition obtained by the present invention can be applied to general anticorrosive coatings, including steel structures that are particularly corrosive and require so-called heavy anticorrosion coatings, such as the inner and outer walls of tanks, chemical plants, bridges, and steel towers. metal products such as roofs, interior and exterior walls of buildings, water supply, sewage, water transmission, oil and crude oil transfer pipes, coal/petroleum mixtures (COM) that require
Suitable for coating the inner and outer surfaces of steel pipes such as seamless pipes for transportation. In particular, the surface coating composition of the present invention has extremely excellent water resistance, solvent resistance, and mechanical strength as described above, so that it has excellent water resistance, solvent resistance, corrosion resistance, rust prevention, and wear resistance on the inner wall surface. Seamless pipes used for transporting crude oil, petroleum products, COM, or coal water mixture (CWM), etc., which require strong mechanical strength such as water resistance, weather resistance, and damage resistance on the outer wall surface. It is most suitable for use as a lining coating for hollow steel pipes such as UO steel pipes and piles for building materials.

〔effect〕

The surface coating composition for metal materials of the present invention has an average particle size of 11
00n or less, has a crosslinked structure, and preferably has a glass transition temperature lower than the value calculated by the weight fraction method, as an essential component, so it does not cause cracking or peeling on the surface of metal materials. Transparency, gloss, without color
It is possible to form a resin film with excellent properties such as smoothness, water resistance, solvent resistance, weather resistance, and mechanical properties.
It is possible to provide a protective film with excellent water resistance, weather resistance, durability, etc. to a metal material without impairing the inherent luster of the metal material, and its utility value is extremely high.

〔Example〕

Next, in order to explain the present invention in more detail, Examples are shown below.

Example 1 [Preparation of aqueous emulsion] Emulsifier 8 shown in Table 1 was placed in a glass reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, a nitrogen introduction tube, and a dropping funnel.
．． 0 parts by weight and 150 parts by weight of water were charged and dissolved, and the inside of the system was purged with nitrogen gas. Separately, 156 parts by weight of an unsaturated monomer mixture consisting of 75 parts by weight of ethyl acrylate, 75 parts by weight of methyl methacrylate, 4.5 parts by weight of N-methylolacrylamide and 1.5 parts by weight of water was prepared. 1
5 parts by weight were added to the reaction vessel and emulsified at 40°C for 30 minutes.Then, the temperature was raised to 60''C, and then the polymerization initiator 2,2'-azobis(N,N'-dimethyleneisobutyramidine) was added. Hydrochloride at 9.0×1O-3some
/ water, dissolved in 48.5 parts by weight of water, added to the reaction vessel, and immediately added 3 parts by weight of the remaining unsaturated monomer.
Continuously dropped into the reaction vessel for 0 minutes and heated to 60°C.
Polymerization was carried out using After dropping the unsaturated monomer, the mixture was aged at 60° C. for 60 minutes to prepare an aqueous emulsion.

[Evaluation of water-based emulsion]

The average particle diameter, crosslinking property (solvent resistance), and glass transition temperature of the aqueous emulsion thus obtained were measured by the following methods.

Average particle size: Coulter Submicron Particle Analyzer (Coulter Electronics, Inc., USA, Coul
The average particle diameter was measured using a ter Model N4 type.

Crosslinking property: 30g of aqueous emulsion adjusted so that the solid content was 40% by weight (solvent resistance) was placed in a 12cm x 1
The mixture was uniformly cast onto a 4 cm glass plate and air-dried at 25°C. The film obtained in this way is 2cm
It was cut into 4 cm pieces, immersed in a petri dish filled with benzene at 20°C for 48 hours, and evaluated as below based on the degree of swelling and solubility of the film.

O: Film area before immersion in benzene (2cm x 4am
) or slightly swollen.

Δ: The degree of swelling is large and the film shape is impaired.

X: The film was dissolved in benzene and became a uniform liquid.

Glass transition temperature (Tg) Seiko Electronics Co., Ltd. thermal analysis measurement device (SSC5000)
Tg was measured using DSC200). The calculated value of Tg was calculated by the weight fraction method (described above).

[Evaluation of film characteristics]

The above aqueous emulsion 3 prepared with a solid content of 20%
0 parts by weight was uniformly cast onto a 12 cw+ x 14 c+a glass plate and air-dried at 25°C to form a film 3, and the film properties were evaluated. Film properties were evaluated based on the following criteria.

Transparency: The haze value of the film was measured using an integral light transmittance measuring device according to JIS K 6714.

Water resistance: The film was cut into pieces of 2 cm x 4 cm and immersed in a petri dish filled with water at 20°C, and the time until the film turned white was visually determined.

0; 10 days or more Δ=2 days or more and less than 10 days ×; less than 2 days Adhesion: The surface of the film was touched with a finger and the sticky feeling was evaluated according to the following criteria.

0: No sticky feeling Δ: Somewhat sticky It was measured.

- [Performance evaluation as a surface coating composition] 7.6 cm
2.6c+m X O, 5c+a steel plate (SPCCH
L-320 finish), aluminum plate (A-1100P,
HL 320 finish) and copper plate (Cl100P, HL
-400 finish) was solvent washed with petroleum ether, air-dried at room temperature, and the aqueous emulsion was coated uniformly using a knife coater so that the resin layer had a thickness of 0.2 cm.

After air-drying at 25°C, the metal surface was coated with a resin layer to provide a test specimen with gloss and water resistance.

Weather resistance and impact resistance were evaluated using the following criteria.

Glossiness: The specimen was measured according to the following criteria.

0: Has the luster inherent to metal.

Δ: The coating layer is slightly translucent and the original luster of the metal is slightly inferior.

×: The coating layer is translucent and lacks the luster inherent to metal.

Water resistance: The specimen was immersed in a Petri dish filled with deionized water and seawater at 20°C for 28 days.

The condition of the coating layer is determined based on the following criteria. It was measured.

0: The coating layer is transparent and has the luster inherent to metal, and the metal plate and coating layer do not peel off.

Δ: The coating layer is translucent, and the luster inherent to the metal is slightly inferior, but the metal plate and coating layer do not peel off.

×: The coating layer becomes white and loses the original luster of metal.
The metal plate and coating are peeled off or can be easily peeled off.

Weather resistance: blistering of the specimen after irradiation for 1000 hours using a JIS K-5400 accelerated weather resistance testing device.

The presence or absence of peeling was visually determined.

Impact resistance: Judgment was made according to JIS K-5400 impact resistance test method A according to the following criteria.

0: There are no cracks or peeling in the film.

Δ: There are some cracks and peeling in the film.

X: There are cracks and peeling in the film.

The properties, film characteristics, and surface coating composition of the aqueous emulsion were evaluated using the methods described above.

The results are shown in Tables 1 and 2, and it can be seen that samples Nos. 1 to 4 are of the present invention and exhibit excellent effects as surface coating compositions for metal materials. Note that samples No. 5 to No. 7 are comparative examples.

Table 2 Example 2 8.0 parts by weight of the emulsifier shown in Table 3, 90 parts by weight of ethyl acrylate, 60 parts by weight of methyl methacrylate, 4.5 parts by weight of N-methylolacrylamide, and 2.5 parts by weight of water. 157 parts by weight of unsaturated monomers and 3.9 parts by weight of potassium persulfate as a polymerization initiator. OX 10'''”mole/
Aqueous phase α, sodium thiosulfate3. OX 10-3mol
e/aqueous phase Q and copper sulfate 5. OX 10″″’ mole/
The water phase was dissolved in 47.5 parts by weight of water, and emulsion polymerization was carried out in the same manner as in Example 1 to prepare an aqueous emulsion.

The properties of the aqueous emulsion thus obtained, the properties of the film formed by air-drying at 20°C, and the performance evaluation as a surface coating composition for metal materials were measured and evaluated in the same manner as in Example 1. The results of the film properties are shown in Table 3. Sample No.8~
Sample No. 11 is an example of the present invention, and Sample Nos. 12-14 and 14' are comparative examples.

In addition, sample No. 8-11 had good gloss, water resistance, weather resistance, and impact resistance for any metal material such as a steel plate, an aluminum plate, and a copper plate.

Example 3 154.5 parts by weight of an unsaturated monomer mixture consisting of 60 parts by weight of n-butyl acrylate, 90 parts by weight of styrene, and 4.5 parts by weight of 2-hydroxyethyl methacrylate, and 8.0 parts by weight of the following emulsifier. Part 4.0 and the polymerization initiator shown in Table 5 were added to Part 9. OX 10'''31
Dissolved in 50 parts by weight of water to form wole/aqueous phase Q,
Emulsion polymerization was carried out in the same manner as in Example 1 at the polymerization and ripening temperatures shown in Table 5 to prepare an aqueous emulsion. The properties of the obtained aqueous emulsion, the properties of the film obtained by air drying at 20° C., and the performance as a surface coating composition for metal materials were measured according to Example 1. The results are shown in Table-4 and Table-5.

Samples Nos. 15, 16.17, 19.20 and 21 are examples of the present invention, and samples Nos. 18 and 22 are comparative examples.

In addition, the mechanical strength of the coatings of Samples Nos. 15 to 17, 19, 20 and 21 are all 150% or more in elongation, 150 Kg/ad or more in tensile strength (strength at break), and the glass transition temperature is 24 ° C. On the other hand, all had good film-forming properties at temperatures below 20°C.

Example 4 The following emulsifiers E-1-E-5c in weight parts shown in Table-6! x
H2so-c3+l5OAC-1t-0 separate Na to agency T
E-2 separately, unsaturated monomer mixtures 1 to 3 shown below were prepared, and emulsion polymerization was performed in the same manner as in Example 1 to prepare an aqueous emulsion. The properties of the obtained aqueous emulsion, the properties of the film formed by air drying at 25° C., and the evaluation as an adhesive were measured according to Example 1. The results are shown in Table-6.

Samples Nos. 23 to 34 are examples of the present invention. In addition, the mechanical strength of the films of samples Nos. 23 to 34 all have an elongation rate of 1.
50% or more, tensile strength (strength at break) 150kg/cl
It was more than f. In addition, in Example 1, sample No.
Aqueous emulsions Nos. 23 and 34 were used to evaluate their performance as surface coating compositions for metal materials. The results are sample-2
For any of the aqueous emulsions No. 3 to 34, coating films of metal materials with excellent gloss, water resistance (deionized water, seawater), weather resistance, and impact resistance are applied to steel plates, aluminum plates, and copper plates. It showed the performance as a composition.

Example 5 Samples Hα1-4 and Nα8-11 obtained in Examples 1 and 2
After adjusting the solid content of the aqueous emulsion to 30% by weight, it was preheated to 90°C, with an outer diameter of 50 aa and a plate thickness of 2 marks,
The film thickness is approximately 5mm on a 10m long UO steel pipe (material 5C-12).
The aqueous emulsion was sprayed onto the inner and outer walls of the υ011 tube so that the emulsion was 0 μ, and then subjected to intensive drying at 120° C. for 15 minutes.

Next, this surface-coated υ0 steel pipe was used as part of an oil transfer pipeline, and a one-year transfer test was conducted. The damage and corrosion properties of the inner and outer wall surfaces of the test UO steel pipes lined with aqueous emulsion were visually measured for samples Ncil~4 and Nα8~11, but no damage was observed with any of the samples. No abnormalities were observed, and it was confirmed that the composition is optimal as a coating composition for the surface of hollow steel pipes such as uO1 steel pipes and seamless pipes used for transporting crude oil or petroleum products.

Example 6 Sample N (1 g-11 aqueous emulsion obtained in Example 2) and ethanol and methylated melamine water-soluble amino resin (Cymel 370 manufactured by Mitsui Toatsu Chemical Co., Ltd.) were blended in the following proportions. This aqueous emulsion mixture was sprayed onto the inner and outer walls of a seamless pipe (material 5C-13) with an outer diameter of 50 mm, a plate thickness of z mm, and a length of 1 Om (material: 5C-13) that had been preheated to 90°C to a film thickness of 50 μm. , further 120℃
Baking was performed by forced drying for 30 minutes.

Next, the seamless pipe was used as part of an oil transfer pipeline, and a one-year transfer test was conducted. Sample & 8
This seamless pipe, lined with a water-based emulsion of ~11 and a methylated melamine-based water-soluble amino resin, showed no damage or corrosion on either the inner or outer wall surfaces. Based on the results of 0 or more, this It has been found that the aqueous emulsion of the invention is also effective as a surface coating composition for metal materials for modification by water-soluble baking.

Example 7 The dispersion stability of the aqueous emulsions of Samples 1 to 34 was evaluated in the following manner. The results are shown in Table-7. The dispersion stability test was conducted as follows.

[Dispersion stability] Aqueous emulsion with solid content adjusted to 40% by weight
After putting sog in a 220m Q glass bottle and sealing it, it was left to stand in a constant temperature room at 25℃ for 6 months and in a constant temperature room at 45℃ for one week, and the appearance, transmittance, viscosity, and average particle size were determined to be 81! The dispersion stability of the aqueous emulsion was evaluated. The appearance, transmittance, viscosity, and average particle diameter were measured by the following methods.

Appearance: Viewed at 25℃! The evaluation was based on the following criteria.

○; Transparent or translucent liquid Δ; Cloudy liquid The absorbance under light irradiation was determined, and the light transmittance (%) was calculated. Viscosity Using a Nibble Tutfield type viscometer (B type viscometer manufactured by Tokyo Keiki Co., Ltd.), 25
The viscosity in °C was measured.

Average particle size: Coulter Submicron Particle Analyzer (Coaltar Electronics Co., USA, Co.
The average particle diameter was measured using a Microwave Converter, Model NJ).

In addition, samples 1 to 4.8 to 11.15 to 17.1 were subjected to a forced heating dispersion stability test that was left in a constant temperature room at 45°C for one week.
Example 1 Aqueous emulsions of 9-21 and 23-34
A film was formed according to Example 1, and the film characteristics and performance as a surface coating agent for metal materials were measured and evaluated in the same manner as in Example 1. Transparency, water resistance, adhesion, solvent resistance (crosslinking), and mechanical strength were all better than Examples 1.2.3 and 4.
Almost the same good results were obtained. Graphs showing changes in particle size distribution before and after the dispersion stability test are shown in FIGS. 2(A) and 2(B).

In addition, sample Nα7 in Table 7 (1) had a large number of extremely large particles and could not be measured due to poor dispersion after being left standing for one week at 45°C. Therefore, both sample Nα1 and sample Na1 were
The changes in particle size distribution after being left at rest for 6 months at ℃ were illustrated and compared.

[Brief explanation of drawings]

Figure 1 shows the product of the present invention (sample N) according to JIS-6781.
These are the measurement results obtained when dumbbells were made from the aqueous emulsions of α1) and before comparison (sample Nα5: film forming temperature: 35° C.), and stress-strain samples were performed on the dumbbells. Solid line 2 Inventive products Broken line: Before comparison Figures 2 (A) and 2 (B) are for the inventive product (sample N).
ULL) and aqueous emulsion before comparison (sample Nα7) are left standing at 25° C. for 6 months.

Claims (2)

[Claims] (1) A surface coating composition for a metal material, characterized in that the average particle diameter is 100 nm or less and an aqueous emulsion having a crosslinked structure is an essential component. (2) The surface coating composition for a metal material according to claim 1, wherein the aqueous emulsion has a glass transition temperature lower than the value calculated by the weight fraction method.