JP3342025B2 - Dispersion stabilizer for pigments - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pigment dispersion stabilizer comprising a polymer having a polyvinyl alcohol-based polymer in a side chain. The dispersion stabilizer is used when preparing aqueous dispersions of various pigments, and the obtained aqueous dispersion is used in the fields of paper processing, cosmetics, ceramic molding, adhesion, and the like.

[0002]

BACKGROUND OF THE INVENTION Aqueous dispersions of pigments are used in a very wide range of fields. Numerous low molecular dispersants and many types of high molecular dispersants such as polycarboxylates are known as dispersants for pigments to obtain this aqueous dispersion. The solution was not satisfactory in terms of stability over time.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pigment dispersion stabilizer for obtaining an aqueous dispersion having sufficient dispersion stabilizing ability and excellent aging stability.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the dispersion stabilizer for pigments comprising a polymer having a polyvinyl alcohol-based polymer in the side chain has been replaced with various inorganic fillers. The present invention has been found to be excellent in the dispersion stability of pigments such as organic fillers, inorganic pigments, organic pigments and various ceramic particles, and has completed the present invention.

The polymer which is a dispersion stabilizer for a pigment of the present invention is a macromonomer unit having a polyvinyl alcohol-based polymer [I] having a vinyl alcohol content of 50 mol% or more and a number average degree of polymerization of 3 to 500. And a polymer [A] having the polymer [I] in the side chain. Here, the structure of the main chain of the polymer [A] is Ru vinyl type polymer der. Specific examples of these polymers include a homopolymer or copolymer of a macromonomer having a polyvinyl alcohol polymer in a side chain, a homopolymer of a polyvinyl ester polymer macromonomer, or a homopolymer of a polyvinyl ether polymer macromonomer. A polymer obtained by solvolysis or hydrolysis of a polymer or a copolymer is useful, and a polymer having a vinyl-type structure such as methacrylate, acrylate, methacrylamide, acrylamide, or styrene is preferred. Used.

The polyvinyl alcohol-based polymer [I] constituting the side chain of the polymer [A] is a water-soluble polymer [A],
Affects water dispersibility and dispersion stabilization ability. The vinyl alcohol content needs to be 50 mol% or more, and preferably 70 mol% or more, from the viewpoints of water solubility, water dispersibility, and dispersion stabilizing ability. The number average polymerization degree of the polyvinyl alcohol-based polymer [I] affects the dispersion stabilizing ability and the properties of the obtained aqueous dispersion of the pigment, and needs to be 3 to 500, preferably 10 to 300. And more preferably 10 to 200. If the degree of polymerization of the polyvinyl alcohol-based polymer [I] is too low, the dispersion stabilizing ability is lowered, and if it is too high, the properties as the polyvinyl alcohol-based polymer are undesirably strongly exhibited. The content of the unit containing the polymer [I] in the polymer [A] affects water solubility, water dispersibility and dispersion stabilizing ability, and is 10 to 10%.
The content is 0% by weight, preferably 15 to 100% by weight. If the content of the unit containing the polymer [I] is too low, the desired performance may not be obtained. The unit other than the vinyl alcohol unit constituting the polymer [I] may be 50 units depending on the purpose.
It can contain less than mol%.

[0007] Examples of such a unit include the following units. That is, ethylene, propylene, 1-
Butenes, olefins such as isobutene, vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl esters such as vinyl versatate, vinyl laurate, vinyl stearate, vinyl benzoate, acrylic acid and Its salts, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-acrylate acrylate
Ethylhexyl, dodecyl acrylate, acrylates such as octadecyl acrylate, methacrylic acid and its salts, methyl methacrylate, ethyl methacrylate,
Methacrylates such as n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, Acrylamide,
N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, acrylamidepropanesulfonic acid and its salts, acrylamidopropyldimethylamine and its salts or quaternary salts, N-methylolacrylamide and its derivatives, etc. Acrylamide derivatives, methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidopropanesulfonic acid and its salts, methacrylamidopropyldimethylamine and its salts or quaternary salts thereof, N-methylolacrylamide and its derivatives, etc. Methacrylamide derivatives, methyl vinyl ether, ethyl vinyl ether,
vinyl ethers such as n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether and stearyl vinyl ether; nitriles such as acrylonitrile and methacrylonitrile; vinyl chloride; vinylidene chloride , Vinyl fluoride, vinyl halides such as vinylidene fluoride, allyl acetate,
Allyl compounds such as allyl chloride; maleic acid and its salts or esters; itaconic acid and its salts or esters; vinylsilyl compounds such as vinyltrimethoxysilane;

Preferred examples of the polymer [A] of the present invention include a homopolymer or copolymer of a polyvinyl alcohol polymer macromonomer. Polymer [A]
Is a copolymer, the structural unit other than the unit containing the polymer [I] is selected depending on the purpose of adjusting the hydrophilicity or hydrophobicity of the polymer [A], imparting ionicity, and the like. The type and amount of the structural unit are not particularly limited as long as it is within the above range, and for example, the following units are exemplified. That is, ethylene, propylene, 1-butene, olefins such as isobutene, methyl acrylate, methacrylic acid and salts thereof, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-methacrylate Butyl, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, 2-hydroxyethyl methacrylate, 2-dimethylaminoethyl methacrylate and salts or quaternary salts thereof Methacrylates such as 2-diethylaminoethyl methacrylate and its salts or quaternary salts, (2-hydroxy) dimethylaminopropyl methacrylate, 3-trimethoxysilylpropyl methacrylate, styrene, p-meth Styrene, α-methylstyrene, chloromethylstyrene, p-styrenesulfonic acid and salts thereof, styrenes such as p-hydroxystyrene and derivatives thereof, acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide , Diacetone acrylamide, acrylamidopropanesulfonic acid and its salts, acrylamidopropyldimethylamine and its salts or quaternary salts thereof,
Acrylamide derivatives such as N-methylolacrylamide and its derivatives, methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid and its salts, methacrylamidopropyldimethylamine and its salts or quaternary, N Methacrylamide derivatives such as methylol methacrylamide and derivatives thereof, N-vinylpyrrolidone, methyl vinyl ether, ethyl vinyl ether, n
-Propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, vinyl ethers such as stearyl vinyl ether, acrylonitrile, nitriles such as methacrylonitrile, vinyl chloride, vinylidene chloride, Vinyl fluoride, vinyl halides such as vinylidene fluoride, allyl acetate,
Allyl compounds such as allyl chloride and allyl alcohol, maleic anhydride, maleic acid and its salts or esters, fumaric acid and its salts or esters, itaconic acid and its salts or esters, and the like, isopropenyl acetate, N-vinylimidazole And the like. Further, as other structural units, macromonomers such as polyoxyalkylene, polyoxyalkylene phosphate, polystyrene, polymethyl methacrylate, and polysiloxane are also exemplified.

The polymer [A] constituting the dispersion stabilizer for pigments of the present invention can be synthesized by several methods, but can be synthesized by homopolymerization or copolymerization of a polyvinyl alcohol polymer macromonomer, or a polyvinyl acetate polymer. A method of hydrolyzing a homopolymer or a copolymer of a polyvinyl ester-based polymer macromonomer such as a polymer macromonomer is preferable from the viewpoint of suppressing the composition and structure of the polymer [A]. Here the like polyvinyl alcohol polymer macromonomer and polyvinyl acetate-based polymer Macromonomer
The methacrylamide, acrylamide, methacrylic ester and styrene structures having an unsaturated double bond portion having excellent radical polymerizability are preferably used, and particularly, methacrylamide, acrylamide and methacryl are preferred. A macromonomer having an acid ester structure is particularly preferably used. The polymerization of the macromonomer and the subsequent solvolysis or hydrolysis are carried out in a conventional manner.

The pigment dispersion stabilizer of the present invention can be used for preparing aqueous dispersions of various pigments. Examples of the pigment include titanium oxide, alumina, aluminum hydroxide, calcium carbonate, talc, clay, silica and carbon black. Various inorganic pigments, organic pigments such as azo pigments, phthalocyanine pigments, isoindolinone pigments, quinacridone pigments, lubricating oils such as spindle oils and gear oils, petroleum products such as paraffin wax, liquid paraffin, asphalt, dibutyl phthalate , Plasticizers such as dioctyl phthalate,
Examples include tar products such as creosote oil and coal tar, natural chemicals such as turpentine oil and rosin, oils and fats such as soybean oil, and organic chemicals such as toluene, xylene and tolylene diisocyanate. The amount of the dispersion stabilizer for a pigment of the present invention to be used in preparing the aqueous dispersion is preferably in the range of 0.01 to 100% by weight, and more preferably 0.1 to 100% by weight based on the dispersion.
A range of 10% by weight is particularly preferred. Further, it is not possible to use a high molecular weight dispersant or a low molecular weight dispersant conventionally used as a dispersion stabilizer together with the dispersion stabilizer of the present invention as long as the effects of the present invention are not impaired. Absent. Further, in the preparation of the aqueous dispersion, a conventionally known method is employed, for example, a general fluid stirrer, a high-speed rotating strong shear type stirrer / disperser, a colloid mill, a pressure nozzle emulsifier, an ultrasonic emulsifier, a paint shaker Etc. are available. There is no particular limitation on the preparation method.

[0011]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the invention thereto. In the examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively, unless otherwise specified.

Reference Example 1 Synthesis of polyvinyl acetate macromonomer A reactor equipped with a stirrer, a reflux condenser and a dropping funnel was charged with a polyvinyl acetate 60 having a 2-hydroxythio group at one end and a number average degree of polymerization of 31. , 40 parts of toluene and 4.16 parts of pyridine, and stirred well at room temperature.
While the reactor was stirred at room temperature, 5.50 parts of methacrylic acid chloride distilled immediately before and 10 parts of dehydrated toluene were mixed well, and the mixture was uniformly added dropwise over 1 hour by a dropping funnel. After completion of the dropwise addition, stirring was continued at room temperature for another 3 hours. Next, 1.70 parts of methanol was added, and the mixture was stirred for 1 hour. Toluene and methanol were distilled off at 40 ° C. under reduced pressure at 400 ° C. while adding 400 parts of toluene in four portions. The product was removed by filtration to obtain a 53.2% toluene solution of the polymer. A part of this toluene solution was put into n-hexane to recover the polymer, which was reprecipitated and purified twice with acetone-hexane, and then dried at 40 ° C under reduced pressure. Proton NMR of this purified polymer was measured using CDCl ₃ as a solvent and was found to be a polyvinyl acetate macromonomer having a number average polymerization degree of 31 and having a methacrylic ester structure at one end. Subsequently, the operation of distilling off toluene under reduced pressure and further adding and distilling off methanol was repeated to remove toluene, thereby obtaining a 60.3% methanol solution of a polyvinyl acetate macromonomer.

Reference Example 2 In a reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet tube and a thermometer, 100 parts of the methanol solution of the polyvinyl acetate macromonomer obtained in Reference Example 1 (concentration: 60.3%) was added. It was charged and replaced with nitrogen by bubbling nitrogen gas at room temperature.
The temperature of the reactor was raised, and when the internal temperature reached 60 ° C., 0.24 part of 2,2-azobisisobutyronitrile was dissolved in 20 parts of methanol, and an initiator solution purged with nitrogen was added, followed by polymerization. Started. After the polymerization was continued under stirring for 20 hours, the polymerization was stopped by cooling, followed by methanol 60.3
Was added and the temperature was adjusted to 40 ° C. Sodium hydroxide 1
28 parts of a 0% methanol solution was added, and methanol decomposition reaction was carried out. After the system was gelled, the system was pulverized, 50 parts of methanol was added, and the mixture was left at room temperature for 24 hours to complete the reaction. Subsequently, 30 parts of methyl acetate and 5 parts of water were added and the mixture was heated to 50 ° C.
, And then purified by Soxhlet washing with methanol, and a polymer having a number average degree of polymerization of 31 and having a polyvinyl alcohol-based polymer [I] in the side chain (Polymer [A] -1)
And). The polymer in the homopolymer of polyvinyl alcohol macromonomer, H of d _6-DMSO solution ¹ -
From the NMR measurement, the vinyl alcohol content of the polyvinyl alcohol-based polymer was 99.0 mol%.

Reference Examples 3 to 9 Number average degree of polymerization of 60 to 1 synthesized in the same manner as in Reference Example 1.
A homopolymer or copolymer of a polyvinyl acetate-based macromonomer obtained by polymerization using the polyvinyl acetate-based macromonomer of Example 20 in the same manner as in Reference Example 2 was prepared in accordance with the method described in Reference Example 2. And solvolysis to obtain polymers ([A] -2 to [A] -8) having various polyvinyl alcohol-based polymers in their side chains. Table 1 shows the results.

[Table 1]

Examples 1 to 4 30 parts of an organic pigment (phthalocyanine blue, insoluble azo dye red or insoluble azo dye yellow) in a paint shaker containing 100 parts of glass beads, a 10% aqueous solution of the polymer shown in the above reference example 60 , 10 parts of water and 0.3 part of an antifoaming agent (Sannopco 485) were charged and dispersed at room temperature for 4 hours. Table 2 shows the results.

Comparative Examples 1-2 Examples 1 and 2 were repeated except that PVA-203 (manufactured by Kuraray Co., Ltd., polymerization degree 300, saponification degree 88%) or Ceramo CD-14 (manufactured by Daiichi Kogyo Seiyaku) was used as a dispersant. The test was performed in the same manner. Table 2 shows the results.

Examples 5 to 8 100 parts of ion-exchanged water, 1 part of the polymer shown in the above reference example
11.7 parts of a 0% aqueous solution, 163 parts of heavy calcium carbonate and 70 parts of light calcium carbonate were charged into a commercial mixer and stirred for 5 minutes to prepare a 70% by weight pigment slurry. Table 2 shows the results.

Comparative Examples 3 and 4 A test was conducted in the same manner as in Example 5 except that PVA-203 or Ceramo CD-14 was used as a dispersant. Table 2 shows the results.

[Table 2]

[0019]

INDUSTRIAL APPLICABILITY The dispersion stabilizer for pigments of the present invention is useful as a dispersion stabilizer for pigments such as organic pigments and inorganic pigments because of the variety of structures and compositions. it is obvious.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-64-4658 (JP, A) JP-A-59-227940 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01F 17/52 C09B 67/40 C08F 16/06

Claims (2)

(57) [Claims] 1. A macromonomer unit having a polyvinyl alcohol-based polymer [I] having a vinyl alcohol content of 50 mol% or more and a number average degree of polymerization of 3 to 500. possess in the chain, methacrylic acid ester
, Acrylic acid ester, methacrylamide, acrylic
Small number selected from the group of
Kutomo one pigment dispersion stabilizer composed of a polymer which have a structure in the main chain. 2. A macromonomer having a polyvinyl alcohol-based polymer is homopolymerized or copolymerized, or a homopolymer or copolymer of a polyvinyl ester-based macromonomer or a polyvinyl ether-based macromonomer is dissolved in a solvent. obtained by decomposition or hydrolysis in the vinyl alcohol content of 50 mol% or more and a number average polymerization degree possess polyvinyl alcohol polymer of 3 to 500 and [I] in the side chain, methacrylic acid esters, acrylic
Luster, methacrylamide, acrylamide
And at least one selected from the group of styrene structures
Pigment dispersion stabilizer composed of a polymer which chromatic in the main chain structure of.