JP2009114351A - Viscosity-improving agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a viscosity-improving agent, capable of imparting excellent finishing properties (smoothness, clarity, sag-preventing property, etc.). <P>SOLUTION: This viscosity improving agent is provided by containing a copolymer of (a) a (meth)acrylic acid (salt), (b) a monomer expressed by formula (1) [wherein, R<SP>1</SP>is H or methyl; R<SP>2</SP>, R<SP>3</SP>are each H, methyl or ethyl; R<SP>4</SP>is an aromatic hydrocarbon group; and (n) is an integer of 3 to 60] and (c) an alkyl (meth)acrylate in which the number of carbon atoms of the alkyl group is 1 to 4, as essential constituting monomers and having 0.1 to 50 wt.% content of the unit (a), 5 to 60 wt.% content of the unit (b) and 5 to 60 wt.% content of the unit (c) based on the total weight of each of the monomer units (a) to (c). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

   The present invention relates to a viscosity improver.

Conventionally, as the polymer type viscosity improver, alkyl-modified polycarboxylic acid (Patent Document 1), cyano group-containing alkyl-modified polycarboxylic acid (Patent Document 2), amino group-containing alkyl-modified polycarboxylic acid (Patent Document 3), etc. It has been known.
Japanese Patent Laid-Open No. 11-246799 JP 2001-279158 A JP 2003-253596 A

  Conventional polymer viscosity improvers have a problem that the smoothness, sharpness, and sagging prevention (finishing property) of the coating film are insufficient. That is, an object of the present invention is to provide a viscosity improver capable of imparting excellent finish properties (smoothness, sharpness and sagging prevention).

（式中、Ｒ^１は水素原子又はメチル、Ｒ^２及びＲ^３は水素原子、メチル又はエチル、Ｒ^４は芳香族炭化水素基、ｎは３〜６０の整数、Ｃは炭素原子、Ｈは水素原子、Ｏは酸素原子を表す。）で表される単量体（ｂ）と、
アルキル基の炭素数が１〜４であるアルキル（メタ）アクリレート（ｃ）とを必須構成単量体とする共重合体を含有してなり、
（ａ）〜（ｃ）の各単量体単位の合計重量に基づいて、（メタ）アクリル酸（塩）（ａ）単位の含有量が０．１〜５０重量％、単量体（ｂ）単位の含有量が５〜６０重量％、アルキル（メタ）アクリレート（ｃ）単位の含有量が５〜６０重量％である点を要旨とする。 The inventor of the present invention has reached the present invention as a result of intensive studies to solve the above problems. That is, the viscosity improver of the present invention is characterized by (meth) acrylic acid (salt) (a),

(Wherein R ¹ is a hydrogen atom or methyl, R ² and R ³ are hydrogen atoms, methyl or ethyl, R ⁴ is an aromatic hydrocarbon group, n is an integer of 3 to 60, C is a carbon atom, and H is hydrogen. An atom, O represents an oxygen atom) and a monomer (b) represented by:
Containing a copolymer having an alkyl (meth) acrylate (c) having 1 to 4 carbon atoms of an alkyl group as an essential constituent monomer;
Based on the total weight of the monomer units (a) to (c), the content of the (meth) acrylic acid (salt) (a) unit is 0.1 to 50% by weight, the monomer (b) The gist is that the content of the unit is 5 to 60% by weight and the content of the alkyl (meth) acrylate (c) unit is 5 to 60% by weight.

  The viscosity improver of the present invention exhibits excellent finishing properties (smoothness, sharpness and sagging prevention).

<(Meth) acrylic acid (salt) (a)>
(Meth) acrylic acid (salt) (a) means acrylic acid, methacrylic acid, acrylate or methacrylate.
Examples of the salt include alkali metal (sodium, potassium, lithium, etc.) salt, alkaline earth metal (magnesium, calcium, etc.) salt, ammonium salt, alkanolamine (monoethanolamine, diethanolamine, triethanolamine etc.) salt and carbon number 1 -4 alkylamine (such as methylamine, ethylamine, propylamine and butylamine) salts and the like.
Of these (meth) acrylic acids (salts), acrylic acid, methacrylic acid, and ammonium methacrylate are preferable, acrylic acid and methacrylic acid are more preferable, and methacrylic acid is particularly preferable.

<Monomer (b)>
Of R ¹ , methyl is preferable from the viewpoint of finish.
Of R ² and R ³ , a hydrogen atom and methyl are preferable, and a hydrogen atom is more preferable from the viewpoint of finish.
Examples of the aromatic hydrocarbon group (R ⁴ ) include a hydrocarbon group having one benzene ring, a hydrocarbon group having two or more independent benzene rings, and a hydrocarbon group having a condensed ring.
The hydrocarbon group having one benzene ring is phenyl, methylphenyl, dimethylphenyl, trimethylphenyl, tetramethylphenyl, pentamethylphenyl, ethylphenyl, propylphenyl, butylphenyl, hexylphenyl, octylphenyl, nonylphenyl, dodecyl. Phenyl, dioctylphenyl, benzyl, phenethyl (2-phenylethyl), hydrocinnamyl (3-phenylpropyl), α-cumyl (2-phenylpropan-2-yl), styryl (2-phenylvinyl), cinnamyl (3-phenyl) Allyl), thymil (2-isopropyl-5-methylphenyl), carbacrylyl (5-isopropyl-2-methylphenyl), cuminyl (4-isopropylbenzyl) and neophyll (2-methyl-2-phenylpropyl). Pill), and the like.

  Examples of the hydrocarbon group having two or more independent benzene rings include xenyl (biphenyl-4-yl), benzylphenyl, dibenzylphenyl, tribenzylphenyl, phenethylphenyl, styrylphenyl, cumenylphenyl, hydrocinnamylphenyl, Cinnamylphenyl, thymilphenyl, carbacrylylphenyl, cuminylphenyl, neophyllphenyl, cumylphenyl, monostyrenated phenyl {1-phenylethylphenyl}, distyrenated phenyl {bis (1-phenylethyl) phenyl}, tristyrenated phenyl {Tris (1-phenylethyl) phenyl}, benzhydryl (diphenylmethyl), trityl (triphenylmethyl) and the like.

  Examples of the hydrocarbon group having a condensed ring include naphthyl, anthryl, phenanthryl and pyrenyl.

  Of these, from the viewpoint of finish, etc., a hydrocarbon group having one benzene ring and a hydrocarbon group having two or more independent benzene rings are preferred, more preferably octylphenyl, nonylphenyl, dodecylphenyl, xenyl, Benzylphenyl, dibenzylphenyl, tribenzylphenyl, cumylphenyl and styrenated phenyl, particularly preferably octylphenyl, nonylphenyl, cumylphenyl and styrenated phenyl.

  n is an integer of 3 to 60, preferably an integer of 10 to 50, and more preferably an integer of 20 to 40. Within this range, the finish is further improved.

  As the monomer (b), (meth) acrylate of 3 to 60 mol adduct of octylphenol ethylene oxide, (meth) acrylate of 3 to 60 mol adduct of nonylphenol ethylene oxide, and (meth) acrylate of 3 to 60 mol adduct of cumylphenol ethylene oxide ) Acrylate, (meth) acrylate of monostyrenated phenol ethylene oxide 3-60 mol adduct, (meth) acrylate of distyrenated phenol ethylene oxide 3-60 mol adduct, (meth) acrylate of tristyrenated phenol ethylene oxide 3-60 mol adduct (meta ) Acrylate, (meth) acrylate of dodecylphenylethylene oxide 3-60 mol adduct, (meth) acrylate of xenyl acyloxide 3-60 mol adduct, benzylphenylethylene oxide 3 0 mole adduct (meth) acrylate, (meth) acrylate of dibenzyl phenylethylene oxide 3 to 60 mol adduct (meth) acrylate and tri-benzyl phenyl ethylene oxide 3-60 mole adduct.

  Among these monomers, (meth) acrylate of octylphenol ethylene oxide 3-60 mol adduct, (meth) acrylate of nonylphenol ethylene oxide 3-60 mol adduct, (meth) of cumylphenol ethylene oxide 3-60 mol adduct Acrylate, (meth) acrylate of monostyrenated phenol ethylene oxide 3-60 mol adduct, (meth) acrylate of distyrenated phenol ethylene oxide 3-60 mol adduct and (meth) of tristyrenated phenol ethylene oxide 3-60 mol adduct Acrylate is preferred.

<Alkyl (meth) acrylate (c)>
Examples of the alkyl (meth) acrylate (c) having 1 to 4 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n- Examples include butyl (meth) acrylate, isobutyl (meth) acrylate, and t-butyl (meth) acrylate. Of these, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate and n-butyl (meth) acrylate are preferred from the viewpoint of finish, etc., particularly preferably methyl (meth) acrylate and ethyl. (Meth) acrylate and n-propyl (meth) acrylate.
In addition, (meth) acrylate means an acrylate or a methacrylate.

  As monomers constituting the copolymer, in addition to (meth) acrylic acid (salt) (a), monomer (b) and alkyl (meth) acrylate (c), other ethylenically unsaturated monomers (D) may be included.

<Other ethylenically unsaturated monomers (d)>
Other ethylenically unsaturated monomers (d) are particularly monomers that can be copolymerized with (meth) acrylic acid (a), monomer (b) and alkyl (meth) acrylate (c). It is not limited, A well-known monomer {For example, patent document 2, patent document 3, Unexamined-Japanese-Patent No. 2004-27208 etc.} etc. can be used.

  Among these other ethylenically unsaturated monomers, from the viewpoint of finish, etc., ethylenically unsaturated carboxylic acid (salt), polyoxyalkylene (alkylene oxide addition mole number 2 to 100) (meth) acrylic acid mono Ester, alkoxy polyalkylene glycol (alkylene oxide addition mole number 2 to 100) (meth) acrylic acid ester, hydroxyalkyl (meth) acrylate, dihydroxyalkyl (meth) acrylate and ethylenically unsaturated amide are more preferable. Crotonic acid, isocrotonic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, polyoxyethylene (ethylene oxide addition mole number 2-100) mono (meth) acrylate, C1-6 aliphatic alcohol ethylene oxide adduct ( With ethylene oxide (Meth) acrylate having 2 to 100 moles), hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, dihydroxyethyl (meth) acrylate, dihydroxypropyl (meth) acrylate and (meth) acrylamide, in particular Preferably maleic acid, fumaric acid, polyoxyethylene (2-100 ethylene oxide addition moles) mono (meth) acrylate, hydroxyethyl (meth) acrylate, dihydroxyethyl (meth) acrylate, dihydroxypropyl (meth) acrylate and (Meth) acrylamide.

  (Meth) acrylic acid (salt) (a), monomer (b), alkyl (meth) acrylate (c) and other ethylenically unsaturated monomers (d) are each one type or two or more types. Any of these may be used.

The content (% by weight) of (meth) acrylic acid (salt) (a) units is (meth) acrylic acid (salt) (a), monomer (b) and alkyl (meth) acrylate (c). Total weight of monomer units {hereinafter abbreviated as “weight of (a) to (c)”. } Is preferably 0.1 to 50, more preferably 1 to 45, and particularly preferably 10 to 40.
The content (% by weight) of the monomer (b) unit is preferably 5 to 60, more preferably 10 to 55, and particularly preferably 20 to 50 based on the weight of (a) to (c). .
The content (% by weight) of the alkyl (meth) acrylate (c) unit is preferably from 5 to 60, more preferably from 7 to 50, particularly preferably from 10 to 40, based on the weight of (a) to (c). It is.
When the copolymer has the other monomer (d) as a constituent unit, the content (% by weight) of the other monomer (d) unit is based on the weight of (a) to (c). 1-100 are preferable, More preferably, it is 5-70, Most preferably, it is 10-40.
Within these ranges, the finish and the like are further improved.

  The copolymer is a known polymerization method {emulsion polymerization, solution polymerization, suspension polymerization, bulk polymerization, etc. (for example, Patent Document 2, Patent Document 3 and Japanese Patent Application Laid-Open No. 2004-27208); Solution polymerization is preferred, more preferably solution polymerization}.

The viscosity improver of the present invention may contain a solvent (an organic solvent and / or water).
Examples of the organic solvent include alcohol and ether.
As alcohol, C1-C8 monool, C2-C12 diol, etc. are contained.
Examples of monools include methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, isobutyl alcohol, isopropyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, and 2-ethylhexyl alcohol.
Examples of the diol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, and tetrapropylene glycol.
Examples of ethers include ethers having 2 to 12 carbon atoms, such as dimethyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, Ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol mono 2-ethylhexyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol Mono butyl ether, ethylene glycol dimethyl ether and diethylene glycol dimethyl ether and the like.

When the solvent is contained, the content (% by weight) is preferably 10 to 10,000, more preferably 40 to 5000, and particularly preferably 100 to 3000, based on the weight of the copolymer.
When the organic solvent and water are contained, the content weight ratio (organic solvent / water) is preferably 10/90 to 99/1, more preferably 20/80 to 98/2, and particularly preferably 30/70 to 97/3.

The viscosity improver of the present invention includes other additives {viscosity improvers other than the present invention, antifoaming agents, dispersants, leveling agents, wetting agents, film-forming aids, antiseptics, fungicides, and water resistance agents. Etc.} (for example, additives described in JP-A No. 54-80349).
When other additives are contained, the total content (% by weight) thereof is preferably from 1 to 70, more preferably from 2 to 60, particularly preferably from 3 to 50, based on the weight of the copolymer. .

The viscosity improver of the present invention can be used to improve the viscosity of various aqueous liquids (particularly paints and the like). The aqueous liquid may be any of an aqueous solution, a water emulsion, an aqueous dispersion, and the like.
The viscosity improver of the present invention is suitable for water emulsions and water-based paints among various aqueous liquids.
As the water emulsion, an emulsion for water-based paint is suitable.
As the water-based paint, water-based emulsion paints are suitable, and industrial emulsion paints, and then industrial emulsion paints excluding automobile paints, particularly water-based emulsion paints for construction, building materials, PCM or heavy anticorrosion are suitable.

The water emulsion and water dispersion are composed of an emulsion and other additives.
Water-based emulsion paints (particularly industrial emulsion paints) are composed of emulsions, aqueous resins, curing agents, pigments, organic solvents, water, and other additives.
As emulsion, acrylic resin emulsion, vinyl acetate resin emulsion, vinyl chloride resin emulsion, acrylic styrene resin emulsion, silicone resin emulsion, urethane resin emulsion, epoxy resin emulsion, fluororesin emulsion, SB latex, SBR latex, ABS latex, NBR latex And CR latex.

  Examples of the aqueous resin include acrylic resin, vinyl resin, oil-free alkyd resin, oil-modified alkyd resin, phenol resin, and epoxy resin.

  Examples of the curing agent include di-, tri-, tetra-, penta- or hexa-methylol melamine and methyl etherified products thereof, urea-formaldehyde condensate, urea-melamine condensate, and the like.

Pigments include inorganic pigments (calcium carbonate, titanium oxide, satin white, barium sulfate, talc, zinc oxide, gypsum, silica, ferrite, etc.) and organic pigments (carbon black, quinacridone red, phthalocyanine blue, polystyrene pigments, etc.) In addition, metallic pigments (aluminum flakes, copper flakes, mica-like iron oxides, mica, scale-like powders in which mica is coated with a metal oxide, and the like) can also be used.
As the organic solvent, the same organic solvents as described above can be used.
As other additives, the same additives as described above can be used.

When the viscosity improver of the present invention is applied to a water-based paint {water-based emulsion paint}, the viscosity improver of the present invention may be added to a grinding stage (kneading step) or a let-down stage (adjustment). You may add to process.
When the viscosity improver of the present invention is added to an aqueous liquid (particularly an emulsion paint), the content (% by weight) of the viscosity improver is 0.01 to 10 based on the weight of the aqueous liquid (emulsion paint). More preferably, it is 0.05-5, Most preferably, it is 0.03-3. Within this range, the finish is further improved.

EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. In addition, with a part or% means a weight part or weight%.
<Example 1>
A monomer mixture comprising 50 parts of methacrylic acid, 5 parts of methacrylate of 20 moles of octylphenol ethylene oxide adduct, and 45 parts of ethyl methacrylate, 50 parts of a 1% ethylene glycol monobutyl ether solution of 2,2′-azobisisobutyronitrile Were respectively stirred at a constant rate over a period of 1.5 hours while being dropped into 350 parts of ethylene glycol monobutyl ether with uniform stirring. The reaction temperature was kept at 80-90 ° C. After maintaining at the same temperature for 3 hours after the completion of dropping, the mixture was cooled to 40 ° C. to obtain viscosity improver 1 {copolymer concentration: 20%} of the present invention.

<Example 2>
A monomer mixture comprising 35 parts of methacrylic acid, 5 parts of acrylic acid, 20 parts of acrylate of 40 mol of nonylphenol ethylene oxide adduct and 40 parts of methyl acrylate, and 0.5% ethylene of 2,2′-azobisisobutyronitrile While 50 parts of the glycol monoethyl ether solution was added dropwise from each dropping funnel to 350 parts of ethylene glycol monoethyl ether at a constant rate over 1.5 hours, the reaction was carried out with uniform stirring. The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after the completion of dropping, the mixture was cooled to 40 ° C. to obtain viscosity improver 2 {copolymer concentration: 20%} of the present invention.

<Example 3>
A monomer mixture consisting of 0.1 part of acrylic acid, 60 parts of methacrylate of cumylphenol ethylene oxide 10 mol adduct and 39.9 parts of ethyl methacrylate, and 2,2′-azobis (4-methoxy-2,4-dimethyl) While 50 parts of a 1% diethylene glycol monoethyl ether solution of valeronitrile was added dropwise to 350 parts of diethylene glycol monoethyl ether at a constant rate from a dropping funnel over a period of 1.5 hours, the reaction was conducted with uniform stirring. The temperature was maintained at 80 to 90 ° C. After maintaining the same temperature for 3 hours after the completion of the dropping, the mixture was cooled to 40 ° C. to obtain the viscosity improver 3 {copolymer concentration: 20%} of the present invention.

<Example 4>
1% of 2,2′-azobis [2- (hydroxymethyl) propionitrile], a monomer mixture consisting of 1 part of acrylic acid, 50 parts of methacrylate of 50 moles of adduct of distyrenated phenol ethylene oxide and 49 parts of butyl methacrylate While 50 parts of the ethylene glycol monobutyl ether solution was added dropwise to 350 parts of ethylene glycol monobutyl ether at a constant rate from the dropping funnel at a constant rate over 1.5 hours, the reaction was performed with uniform stirring. The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after the completion of dropping, the mixture was cooled to 40 ° C. to obtain the viscosity modifier 4 {copolymer concentration: 20%} of the present invention.

<Example 5>
A monomer mixture comprising 10 parts of methacrylic acid, 30 parts of methacrylate of 60 moles of octylphenol ethylene oxide adduct and 60 parts of ethyl methacrylate, and 50 parts of a 1% triethylene glycol monomethyl ether solution of 2,2′-azobisisobutyronitrile. Were added to 350 parts of triethylene glycol monomethyl ether at a constant rate from the dropping funnel over a period of 1.5 hours, and reacted with uniform stirring. The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after the completion of dropping, the mixture was cooled to 40 ° C. to obtain viscosity improver 5 {copolymer concentration: 20%} of the present invention.

<Example 6>
A monomer mixture consisting of 45 parts of methacrylic acid, 10 parts of an acrylate of 3 moles of nonylphenol ethylene oxide adduct and 45 parts of ethyl methacrylate, 50 parts of a 1% ethylene glycol monobutyl ether solution of 2,2′-azobisisobutyronitrile Were added to 350 parts of ethylene glycol monobutyl ether at a constant rate from the dropping funnel over a period of 1.5 hours, and reacted with uniform stirring. The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after the completion of dropping, the mixture was cooled to 40 ° C. to obtain the viscosity improver 6 {copolymer concentration: 20%} of the present invention.

<Example 7>
A monomer mixture consisting of 38 parts of methacrylic acid, 55 parts of acrylate of 10 mol of cumylphenol propylene oxide and 40 mol of ethylene oxide (block copolymer) and 7 parts of butyl acrylate, and 2,2′-azobisisobutyro While 50 parts of a 1% ethylene glycol monobutyl ether solution of nitrile was added dropwise to 350 parts of ethylene glycol monobutyl ether at a constant rate from a dropping funnel over a period of 1.5 hours, the reaction was performed with uniform stirring. The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after the completion of dropping, the mixture was cooled to 40 ° C. to obtain viscosity improver 7 {copolymer concentration: 20%} of the present invention.

<Example 8>
A monomer mixture consisting of 40 parts of methacrylic acid, 10 parts of an acrylate of 5 moles of tristyrenated phenol propylene oxide / 40 moles of ethylene oxide (random copolymerization) and 50 parts of ethyl methacrylate, and 2,2′-azobisisobutyrate While 50 parts of 0.5% ethylene glycol monobutyl ether solution of nitrile was added dropwise to 350 parts of ethylene glycol monobutyl ether at a constant rate from a dropping funnel over a period of 1.5 hours, the reaction was performed with uniform stirring. The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after completion of dropping, the mixture was cooled to 40 ° C. to obtain the viscosity improver 8 {concentration of copolymer: 20%} of the present invention.

<Example 9>
A monomer mixture comprising 40 parts of methacrylic acid, 50 parts of methacrylate of 10 moles of octylphenol butylene oxide and 40 moles of ethylene oxide (block copolymer) and 10 parts of ethyl acrylate, and 2,2′-azobis (4-methoxy-2 While stirring, 50 parts of a 1% ethylene glycol monomethyl ether solution of 1,4-dimethylvaleronitrile was added dropwise to 350 parts of ethylene glycol monomethyl ether at a constant rate from a dropping funnel over a period of 1.5 hours. The reaction temperature was maintained at 80 to 90 ° C. After the completion of the dropwise addition, the temperature was maintained at the same temperature for 3 hours and then cooled to 40 ° C. to obtain the viscosity improver 9 {copolymer concentration: 20%} of the present invention.

<Example 10>
A monomer mixture comprising 40 parts of methacrylic acid, 5 parts of acrylic acid, 50 parts of methacrylate of 50 mol nonylphenol ethylene oxide adduct and 5 parts of butyl acrylate, and 2,2′-azobis (4-methoxy-2,4-dimethylvalero) 50 parts of a 1% isopropyl alcohol solution of nitrile was allowed to react with stirring uniformly while dropping into 350 parts of isopropyl alcohol at a constant rate from a dropping funnel over a period of 1.5 hours. After the completion of dropping, the temperature was kept at the same temperature for 3 hours and then cooled to 40 ° C. to obtain the viscosity improver 10 {copolymer concentration: 20%} of the present invention.

<Example 11>
A monomer mixture comprising 35 parts of methacrylic acid, 45 parts of acrylate of 35 moles of cumylphenol ethylene oxide and 5 moles of propylene oxide (block copolymer), 20 parts of butyl methacrylate and 1 part of methacrylamide, and 1 of sodium persulfate 50 parts of an aqueous solution of 50% each was reacted with stirring uniformly while being dropped into 350 parts of water at a constant rate from a dropping funnel over a period of 1.5 hours. The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after completion of dropping, the mixture was cooled to 40 ° C. to obtain the viscosity improver 11 {concentration of copolymer: 20%} of the present invention.

<Example 12>
A monomer mixture consisting of 30 parts of methacrylic acid, 50 parts of an acrylate of 30 parts of monostyrenated phenol ethylene oxide and 10 moles of propylene oxide (random copolymerization), 20 parts of ethyl methacrylate and 100 parts of acrylamide, and 2,2′- While 50 parts of a 1% ethylene glycol monobutyl ether solution of azobisisobutyronitrile was added dropwise to 350 parts of ethylene glycol monobutyl ether at a constant rate from a dropping funnel over a period of 1.5 hours, the reaction was carried out with uniform stirring. The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after completion of dropping, the mixture was cooled to 40 ° C. to obtain the viscosity improver 12 {copolymer concentration: 20%} of the present invention.

<Example 13>
A monomer mixture consisting of 50 parts of methacrylic acid, 30 parts of acrylate of 30 moles of octylphenol ethylene oxide adduct, 20 parts of methyl acrylate and 5 parts of 2-hydroxyethyl acrylate, and 1% of 2,2′-azobisisobutyronitrile While 50 parts of diethylene glycol monobutyl ether solution was added dropwise to 350 parts of diethylene glycol monobutyl ether at a constant rate from a dropping funnel at a constant rate over 1.5 hours, the reaction was performed with uniform stirring. The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after the completion of dropping, the mixture was cooled to 40 ° C. to obtain the viscosity improver 13 {copolymer concentration: 20%} of the present invention.

<Example 14>
A monomer mixture comprising 40 parts of methacrylic acid, 50 parts of methacrylate of 7 mol nonylphenol ethylene oxide adduct, 10 parts of ethyl methacrylate, 20 parts of maleic acid, 20 parts of 2,3-dihydroxypropyl methacrylate and 30 parts of acrylamide; 50 parts of a 1% diethylene glycol monobutyl ether solution of '-azobisisobutyronitrile was reacted with uniform stirring while dropping dropwise into 350 parts of diethylene glycol monobutyl ether at a constant rate over 1.5 hours from a dropping funnel. . The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after completion of dropping, the mixture was cooled to 40 ° C. to obtain the viscosity improver 14 {copolymer concentration: 20%} of the present invention.

<Example 15>
A monomer mixture consisting of 50 parts of methacrylic acid, 20 parts of methacrylate of 50 mol of cumylphenol ethylene oxide, 30 parts of ethyl acrylate, 5 parts of methacrylamide and 5 parts of 2-hydroxyethyl acrylate, and 2,2′-azobis ( Stir uniformly while adding 50 parts of a 0.5% isopropyl alcohol solution of 4-methoxy-2,4-dimethylvaleronitrile to 350 parts of isopropyl alcohol at a constant rate from a dropping funnel over a period of 1.5 hours. The reaction temperature was maintained at 70 to 80 ° C. After the completion of the dropwise addition, the temperature was maintained at the same temperature for 3 hours and then cooled to 40 ° C., and the viscosity improver 15 {concentration of copolymer: 20%} of the present invention was added. Obtained.

<Example 16>
A monomer mixture consisting of 40 parts of methacrylic acid, 30 parts of methacrylate of 40 parts of an adduct of tristyrenated phenol ethylene oxide, 30 parts of ethyl methacrylate, 20 parts of 2,3-dihydroxypropyl acrylate and 20 parts of acrylamide, and 2,2′- 50 parts of a 1% diethylene glycol monoethyl ether solution of azobisisobutyronitrile was added to 350 parts of diethylene glycol monoethyl ether at a constant rate from a dropping funnel over a period of 1.5 hours, and the mixture was uniformly stirred and reacted. . The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after the completion of dropping, the mixture was cooled to 40 ° C. to obtain the viscosity improver 16 {copolymer concentration: 20%} of the present invention.

<Comparative Example 1>
1100 parts water, 176.9 parts methacrylic acid, 30.6 parts acrylate of ethyl alcohol ethylene oxide 30 mol adduct, 63.5 parts methyl acrylate, 7.6 parts octyl acrylate, and polyoxyethylene (ethylene oxide 20 mol adduct) stearyl While stirring a mixture of 21.2 parts of ether sulfate sodium salt, 100 parts of a 0.2% aqueous solution of potassium persulfate was added dropwise at a constant rate over 3 hours to cause a reaction. The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after the completion of dropping, the mixture was cooled to 40 ° C. to obtain a comparative viscosity improver H1 {concentration of copolymer: 20%, alkyl-modified polycarboxylic acid described in Patent Document 1}. .

<Comparative example 2>
A monomer mixture consisting of 70 parts of acrylic acid, 190 parts of methacrylic acid and 60 parts of acrylonitrile and 15 parts of a 5% aqueous sodium persulfate solution were respectively added dropwise to 1232 parts of water at a constant rate over 1.5 hours. The reaction was carried out with uniform stirring. The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after the completion of dropping, the mixture was cooled to 40 ° C., and the viscosity improver H2 for comparison {concentration of copolymer: 20%, cyano group-containing alkyl-modified polycarboxylic acid described in Patent Document 2} Got.

<Comparative Example 3>
1100 parts of water, 95 parts of methacrylic acid, 57 parts of ethyl acrylate, 30 parts of acrylamide, 20 parts of acrylate of 40 mol adduct of butyl alcohol ethylene oxide, 78 parts of styrene, polyoxyethylene (25 mol adduct of ethylene oxide) sodium lauryl ether phosphate diester sodium While stirring a mixture of 15 parts of salt and 10 parts of polyoxyethylene (35 mol adduct of ethylene oxide) lauryl ether, 100 parts of a 0.2% aqueous solution of potassium persulfate was added dropwise at a constant rate over 3 hours to react. The reaction temperature was kept at 80-90 ° C. After maintaining the same temperature for 3 hours after the completion of dropping, the mixture was cooled to 40 ° C. to obtain a comparative viscosity improver H3 {copolymer concentration: 20%, alkyl-modified polycarboxylic acid described in Patent Document 3}. .

The performance of the viscosity improvers obtained in Examples 1 to 16 and Comparative Examples 1 to 3 (smoothness, sharpness, sagging prevention and high shear viscosity reduction) was evaluated by the following methods, and the results are shown in Table 1. It was.
<Sag prevention>
(1) Preparation of emulsion paint for evaluation (thermosetting industrial emulsion paint) 4 parts for evaluation sample {viscosity improver}, 180 parts acrylic emulsion (Boncoat EC-819, manufactured by Dainippon Ink & Chemicals), water-soluble 220 parts of acrylic resin (Boncoat 3980, manufactured by Dainippon Ink Chemical Co., Ltd.), 40 parts of water-soluble melamine resin (Cymel 370, manufactured by Mitsui Cyanamid Co., Ltd.), titanium dioxide (Taipeku CR-95, Ishihara Sangyo Co., Ltd. 170 parts, 50 parts of ethylene glycol monobutyl ether, 500 parts of deionized water and 6 parts of an antifoaming agent (SN deformer 399, manufactured by San Nopco Co., Ltd.) were uniformly mixed to obtain an adjustment solution.
Viscosity of this adjustment solution {Ford Cup NO. 4 (manufactured by Yasuda Seiki Seisakusho Co., Ltd.)} was diluted with deionized water so as to obtain 45 seconds for an emulsion coating for evaluation.

(3) Coating Emulsion paint for evaluation is applied to a degreased tin plate (20 cm x 30 cm, thickness: 0.3 mm) by air spray coating (Wider W-88 Cupgun, Iwata Coating Machine Co., Ltd., film thickness gradient coating, exhaust Pressure: 4 kg / cm ² ) to obtain a coated tin plate.
In the air spray coating, the discharge amount was changed so that the film thickness was 30 μm, the trial coating was performed, and then the main coating was performed.

(3) Evaluation Standing the painted tin plate vertically, setting in the booth for 5 minutes (booth temperature: 25 ° C, relative humidity: 75% RH), and observing the dripping condition of the paint immediately afterwards with the naked eye It was evaluated with.

○: There is no paint dripping △: There is a little paint dripping ×: There are many paint dripping traces

<Smoothness>
After evaluating the sagging prevention property, the coated tin plate was left in a 160 ° C. oven for 20 minutes to obtain a baked tin plate. After the baking tin plate was cooled to room temperature (about 25 ° C.), the surface of the coating film was observed with the naked eye and evaluated according to the following criteria.

○: Almost no repelling or craters Δ: There are a few repellings or craters ×: There are many repellings or craters

<Vividness>
Subsequent to the evaluation of the smoothness, the surface of the coating film was measured at 6 locations each for 20 ° gloss (gloss meter VGS-300A, manufactured by Nippon Denshoku Industries Co., Ltd.), and the average value thereof was defined as sharpness. It shows that it is excellent in the sharpness, so that this value is high.

<High shear viscosity reduction>
The viscosity at 1000 (1 / S) of the emulsion paint for evaluation was measured with a rheometer (manufactured by HAAKE, Rheo Stress RS75). It shows that it is excellent in the high shear viscosity decreasing property, so that this value is low.

注１）調整溶液を希釈して評価用エマルション塗料を得るために用いた脱イオン水の量（部）
注２）ブランク：評価用サンプル｛粘性改良剤｝の代わりに脱イオン水を用いた以外、実施例及び比較例と同様に評価した。

Note 1) Amount of deionized water used to dilute the adjustment solution to obtain an emulsion paint for evaluation (parts)
Note 2) Blank: Evaluated in the same manner as in Examples and Comparative Examples except that deionized water was used instead of the evaluation sample {viscosity improver}.

  The viscosity improver of the present invention was extremely superior to the viscosity improver of the comparative example in terms of finish (smoothness, sharpness and sagging prevention) and high shear viscosity-reducing properties.

  The viscosity improver of the present invention can be used to improve the viscosity of various aqueous liquids (particularly paints and the like). The viscosity improver of the present invention is suitable for water-based paints among various aqueous liquids, and further suitable for water-based emulsion paints, particularly industrial emulsion paints (such as construction, building materials, PCM and heavy anticorrosion paints).

Claims (4)

(Meth) acrylic acid (salt) (a);

(Wherein R ¹ is a hydrogen atom or methyl, R ² and R ³ are hydrogen atoms, methyl or ethyl, R ⁴ is an aromatic hydrocarbon group, n is an integer of 3 to 60, C is a carbon atom, and H is hydrogen. An atom, O represents an oxygen atom) and a monomer (b) represented by:
Containing a copolymer having an alkyl (meth) acrylate (c) having 1 to 4 carbon atoms of an alkyl group as an essential constituent monomer;
Based on the total weight of the monomer units (a) to (c), the content of the (meth) acrylic acid (salt) (a) unit is 0.1 to 50% by weight, the monomer (b) A viscosity improver characterized in that the content of the unit is 5 to 60% by weight and the content of the alkyl (meth) acrylate (c) unit is 5 to 60% by weight. Furthermore, the viscosity improving agent of Claim 1 containing a solvent. A water emulsion comprising the viscosity improver according to claim 1 or 2. A water-based emulsion paint for building, building materials, PCM or heavy corrosion protection, comprising the viscosity improver according to claim 1 or 2.