JPH04239591A - Heat-and photo-oxidative deterioration preventive dispersion - Google Patents

Abstract

PURPOSE:To obtain the title highly concentrated, industrially useful dispersion excellent in storage stability with time, easy to handle by dispersing in water an antioxidant and/or light stabilizer of specified particle size, emulsifier and dispersion stabilizer. CONSTITUTION:The objective dispersion can be obtained by dispersing in an aqueous medium (A) 25 to <60wt.% of an antioxidant such as 2,6-di-t-butyl-p- cresol and/or light stabilizer such as bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate with an average particle size of <=5 (pref. <=3)mum, (B) 0.1-10 (pref. 0.5-5)wt.% of emulsifier(s) of anionic, nonionic, cationic and/or amphoteric base, and (C) <0.5 (pref. 0.05-0.4)wt.% of a dispersion stabilizing auxiliary such as gum arabi or polyhydric alcohol.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION The present invention relates to thermal and photooxidative antioxidant dispersions containing antioxidants and/or light stabilizers dispersed in an aqueous medium.

0002

[Prior Art] Resins such as vinyl chloride resins and ABS resins that are polymerized in an aqueous medium by suspension polymerization or emulsion polymerization are oxidized by oxygen and light in the air, so antioxidants and light stabilizers are added. However, in order to uniformly disperse them in the resin, it is preferable to add them while the polymer is in a solution or slurry state during polymerization. Various antioxidants and light stabilizers are frequently used in vinyl chloride resin, ABS resin, MBS resin, etc. to prevent initial discoloration and improve heat resistance and weather resistance, but most of these are in the form of powder. Due to its water repellency, it is difficult to automatically add a predetermined amount, especially when adding to a polymer in the molten state or slurry state during polymerization, since the system is usually under pressure. It is difficult to press fit. For this reason, conventional methods have been taken such as dissolving it in an appropriate solvent and adding it, or melting it above its melting point and emulsifying and dispersing it. However, the method of dissolving it in an organic solvent involves suspension polymerization in an aqueous medium. In some cases, the COD in the wastewater increases, so this is not the preferred method.Furthermore, the method of melting and emulsifying and dispersing has difficulties in terms of dispersion stability over time, dispersion of highly concentrated liquids, etc., so it is not the preferred method. This is the current situation.

0003

[Problems to be Solved by the Invention] Previously, there has been a method in which a powdered antioxidant is dispersed in water to form an emulsion using either an emulsifier or a suspending agent, or a combination of an emulsifier and a suspending agent, and then added. have been proposed (JP-A-60-63274, JP-A-60-149608, JP-A-60-186547, JP-A-63-2187).
No. 11). However, these methods are still not satisfactory in terms of stability over time and workability during addition as a method for dispersing high-concentration antioxidants. Therefore, an object of the present invention is to obtain a highly concentrated aqueous dispersion having good storage stability over time and good workability.

0004

[Means for Solving the Problems] As a result of extensive research in order to solve the above problems, the present inventors have developed a powdered antioxidant or light stabilizer that is mixed with an emulsifier by wet pulverization.
The present invention was completed based on the discovery that an aqueous dispersion with excellent storage stability and easy handling can be obtained by dispersing the dispersion in water together with a dispersion stabilizing aid of %wt% or less.

That is, the present invention provides antioxidants and/or light stabilizers, emulsifiers, and
．． The present invention relates to thermal and photooxidative anti-degradation dispersions characterized in that they contain less than 5% by weight of dispersion stabilizing aids.

[0006] The high concentration antioxidant according to the present invention means that the antioxidant concentration in the dispersion is at least 25% by weight or more,
Although the concentration is less than 60% by weight, it is not limited to this concentration. If it exceeds 60% by weight, fluidity becomes extremely poor and dispersibility becomes impossible, which is not preferable. The average particle size of the antioxidant dispersed in the aqueous medium according to the present invention is 5 μm.
In order to maintain storage stability, it is necessary that the thickness be 3 μm or less, preferably 3 μm or less. The average particle diameter here refers to the particle diameter when the volume reaches 50% (volume average diameter)
point to

[0007] The antioxidants that can be used in the present invention are 2.
6-ditert-butyl-p-cresol, 3-tert-butyl-4-hydroxyanisole, 2-tert-butyl-4
-Hydroxyanisole, 2,2'-methylenebis(
4-methyl-6-tert-butylphenol), 2,2'
-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-
6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), styrenated phenol, styrenated-p-cresol, 1,1
,3-tris(2-methyl-4-hydroxy-5-tertiary
butylphenyl)butane, tetrakis-[methylene-
3-(3,5-ditert-butyl-4-hydroxyphenyl)propionate]methane, n-octadecyl-3-
(3,5-ditertiary butyl-4-hydroxyphenyl)
Propionate, 1,3,5-trimethyl-2,4,6
-tris(3,5-ditert-butyl-4-hydroxybenzyl)benzene, 2,2'-dihydroxy-3,3
'-di(α-methylcyclohexyl)-5,5' -
Dimethyldiphenylmethane, 2,2'-methylenebis(2,6-ditert-butylphenol), Tris(3,
5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, tris[β-(3,5-di-tert-butyl-
4-hydroxyphenyl)propionyloxyethyl]
Isocyanurate, bis[2-methyl-4-(n-alkylthiopropionyloxy)-5-tert-butylphenyl] sulfide, 1-oxy-3-methylisopropylbenzene, 2,5-di-tert-butylhydroquinone,
2,2'-methylenebis(4-methyl-6-nonylphenol), alkylated bisphenol, 2,5-ditertiary amylhydroquinone, polybutylated bisphenol A, bisphenol A, 2,6-ditertiary butyl-
4-ethylphenol, 2,6-bis(2-hydroxy-3-tert-butyl-5-methylbenzyl)-4-methylphenol, 1,3,5-tris(4-tert-butyl-3- Hydroxy-2,6-dimethylbenzyl)isocyanurate, terephthaloyl-di(2,6-dimethyl-
4-tert-butyl-3-hydroxybenzyl sulfide), 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-α-dimethylamino-p-cresol, 2
, 2'-methylenebis(4-methyl-6-cyclohexylphenol), hexamethylene glycolbis(3
, 5-ditert-butyl-4-hydroxyphenyl)propionate, 6-(4-hydroxy-3,5-ditert-butylanilino)-2,4-bis-octylthio-1,
3,5-triazine, 2,2-thio[diethyl-bis-
3-(3,5-ditert-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-ditert-butyl-4-hydroxyhydrocinnamide), 3, 5-ditertiary-butyl-4-hydroxybenzyl-phosphate diethyl ester, 2,4-dimethyl-6-tertiary-butylphenol, 4,4'-methylenebis(2,6-ditertiary-butylphenol), 4 ,4'
-thiobis(2-methyl-6-tert-butylphenol), triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 2,4,6-tri-tert-butylphenol Tertiary butylphenol, 2,4,6-trimethylphenol, bis[3,3-
Bis(3-tert-butyl-4-hydroxyphenyl)butyric acid] glycol ester, 4-hydroxymethyl-2,6-ditert-butylphenol, bis(3-tert-butyl-4-hydroxyphenyl)butyric acid
-Methyl-4-hydroxy-5-tert-butylbenzyl) sulfide, 3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1 ,1-dimethylethyl]-2,4,
8,10-tetraoxaspiro[5.5]undecane,
Phenolic antioxidants such as butylation reaction products of p-cresol and dicyclopentadiene, N-phenyl-N
'-isopropyl-p-phenylenediamine, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, 2,2,4-trimethyl- 1,2-dihydroquinoline polymer, amine antioxidants such as diallyl-p-phenylenediamine, dilaurylthiodipropionate, dimyristylthiodipropionate, distearylthiodipropionate, ditridecylthiodipropionate , didocosylthiodipropionate, pentaerythritol-tetra(β-laurylthiopropionate) ester, sulfur-based antioxidants such as 2-mercaptobenzimidazole, tris(2,4-ditertiary butylphenyl) phosphorus, Examples include, but are not limited to, phosphorus-based antioxidants such as Phite. These antioxidants may be used alone or in combination of two or more. In addition, as a light stabilizer that can be used in the present invention, bis(2
, 2,6,6-tetramethyl-4-piperidinyl) sebacate, 1-[2-{3-(3,5-ditertiary butyl-
4-hydroxyphenyl)propionyloxy}ethyl]-4-[3,5-ditertiary butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-tetramethylpiperidine, dimethyl succinate 2 -(4-hydroxy-2,2,6,6-tetramethyl-4-piperidine)ethanol condensate, 2,4-dichloro-6-(1
,1,3,3-tetramethylbutylamino)-1,3-
Triazine/N,N'-bis(2,2,6,6-tetramethyl-4-piperidine)hexamethylenediamine polycondensate, poly{[6-morpholino-(1,3,5-triazine)-2, 4-diyl]-[4-(2,2,6,6
-Tetramethylpiperidyl)iminohexamethylene]-
[4-(2,2,6,6-tetramethylpiperidyl)imino]}, poly{[6-(1,1,3,3-tetramethylbutylimino)-1,3,5-triazine-2, 4-
diyl]-[4-(2,2,6,6-tetramethyl-4
-piperidyl)-iminohexamethylene]-[4-(2
, 2,6,6-tetramethyl-4-piperidyl)-imino]}, 1,2-ethylenebis(N-3,3,5,5-
tetramethyl-2-piperazinone), poly(N,N'
-bis(2,2,6,6-tetramethylpiperidyl)hexamethylenediamine/1,2-dibromoethylene, N
Hindered amine stabilizers such as -(p-ethoxycarbonylphenyl)-N'-ethyl-N'-phenylformamide, [2,2'-thiobis(4-tertiary octylphenolate)]-n-butylamine nickel [
II], [2,2'-thiobis(4-tertiary octylphenolate)] triethanolamine nickel [I
I], [2,2'-thiobis(4-tertiary octylphenolate)]cyclohexyldiethanolamine nickel [II], [2,2'-thiobis(4-tertiary octylphenolate)]-2- Ethylhexylamine nickel [II], bis(3,5-ditertiary butyl-
Nickel-based light stabilizers such as 4-hydroxybenzylphosphoric acid) monoethyl ester nickel salt, 2-
Hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-stearyloxybenzophenone, 2-hydroxy-4-dodecyl Oxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate, 2-hydroxy-4
-Methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2-hydroxy-4-benzoyloxybenzophenone, 5-chloro-2-hydroxybenzophenone, 2-
Hydroxy-4-(2-hydroxy-3-methacryloxy)propoxybenzophenone, 2-hydroxy-4
-methoxy-4'-chlorobenzophenone, 2,4-
Dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,
2'-dihydroxy-4-n-octyloxybenzophenone, methyl O-benzoylbenzoate, 2,2'
,4,4'-tetrahydroxybenzophenone, 2,
Benzophenone light stabilizers such as 4,5-trihydroxybutyrophenone, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-
3-tert-butyl-5-methylphenyl)benzotriazole, 2-(2-hydroxy-3,5-ditert-butyl-methylphenyl)benzotriazole, 2-(2-
Hydroxy-3,5-ditertiary-butylphenyl)-5-
Chlorobenzotriazole, 2-(2-hydroxy-3
, 5-dipentylphenyl)benzotriazole, 2-
(2-hydroxy-4-octyloxyphenyl)benzotriazole, 2-(2H-benzotriazole-2
benzotriazole stabilizers such as -yl)-4-(1,1,3,3-tetramethylbutyl)phenol, phenyl salicylate, 4-tert-butylphenyl salicylate, 4-octylphenyl salicylate salicylate light stabilizers such as resorcinol monobenzoate, 2,
4-Ditert-butylphenyl-3,5-di-tert-butyl-4-hydroxy-benzoate, N-(2-ethylphenyl)-N'-(2-ethoxy-5-tert-butylphenyl) Oxalic acid diamide, ethyl 2-cyano-3
, 3-diphenylacrylate, 2-ethylhexyl
2-cyano-3,3-diphenylacrylate, 2,5
-Bis[5-tert-butylbenzoxazolyl (2)]thiophene, p-methoxyphenol, n-hexadecyl 3,5-ditert-butyl-4-hydroxybenzoate, 2-ethylhexyl 4-methoxy cinnamate,
Examples include, but are not limited to, ultraviolet absorbers such as methyl p-aminobenzoate, hexamethylphosphoric triamide, and 2-ethylhexyl-4-dimethylaminobenzoate. These light stabilizers may be used alone or in combination of two or more, or in combination with the above-mentioned antioxidants.

[0008] As the emulsifier, anionic, nonionic, cationic, or amphoteric emulsifiers can be used. Examples of anionic emulsifiers include higher fatty acids, alkyl sulfates, alkylbenzene sulfonic acids, dialkyl sulfosuccinates, and alkyl sulfosuccinates. Examples include alkali metal salts or alkaline earth metal salts or ammonium salts of phosphoric acid esters, polyoxyethylene alkyl sulfate esters, or alkyldiphenyl ether disulfonic acids, and naphthalene sulfonic acid formalin condensates. Examples of nonionic emulsifiers include polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether,
Examples include polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxyethylene oxypropylene block polymer, and the like. Examples of cationic or amphoteric emulsifiers include alkylamine salts, quaternary ammonium salts, and alkylbetaines. These emulsifiers may be used alone or in combination of two or more as necessary. The proportion of the emulsifier in the dispersion is preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight, based on the actual active ingredient. The proportion of emulsifier in the dispersion is 10% by weight
Exceeding this is undesirable as the COD in the wastewater becomes high. Further, if it is less than 0.1% by weight, storage stability cannot be maintained even if a dispersion stabilizing agent is added, which is not preferable.

Natural or synthetic substances are used as dispersion stabilizing aids, such as gum arabic, gelatin, cellulose derivatives (methylcellulose, sodium carboxymethylcellulose, potassium carboxymethylcellulose, etc.),
Starch derivatives (sodium starch glycolate, sodium starch phosphate, carboxymethyl starch, etc.), acrylic acid or polyacrylic acid and their salts (sodium salts, etc.), polyhydric alcohols (polyethylene glycol, polypropylene glycol, etc.), polyvinyl alcohol , maleic anhydride-styrene copolymer, water-soluble polyester, and the like.

One of the highlights of the present invention is that the dispersion stabilizing agent is contained in an amount of less than 0.5% by weight based on the total amount of the dispersion.
It is preferably added in an amount of 0.05 to 0.4% by weight to improve storage stability and workability of high-viscosity dispersions and low-viscosity dispersions. If it is added in an amount of 0.5% by weight or more, the viscosity of a highly viscous dispersion increases and it may solidify during storage, resulting in extremely poor workability and no benefit.

According to the present invention, a powdered antioxidant or light stabilizer having an average particle size of 5 μm or less is substantially uniformly dispersed in water (preferably deionized water or distilled water) together with an emulsifier and a dispersion stabilizing agent. The method of production is not limited as long as it is dispersed in a batchwise or continuous manner. That is, a powdered antioxidant and/or light stabilizer can be produced together with an emulsifier, a dispersion stabilizing aid, and water using a bowl mill, tube mill, Premier colloid mill, Shallotte colloid mill, Dyno mill, Visco mill, sand grinder, or the like.

0012

EXAMPLES The present invention will be explained in more detail in the following Examples, but the present invention is not limited thereto.

Example 1 50 g of 2,2'-methylenebis(4-methyl-6-tert-butylphenol) having an average particle diameter of 5 μm or more as measured by a laser diffraction particle size distribution analyzer, 1.2 g of sodium dodecylbenzenesulfonate. 5g, 0.2g of methyl cellulose (MC), 48.3g of ion-exchanged water, and 150g of spherical glass beads with a diameter of 1.5mm in 300ml.
The mixture was placed in a large beaker and stirred at high speed for 17 hours using a three-one motor, and the beads and dispersion were filtered through an 80-mesh sieve. The resulting aqueous dispersion had an average particle size of 2.5 μm and B
The viscosity measured with a type rotational viscometer was 500 CPS/20° C., and no separated precipitate was formed even after being left at room temperature for 2 months. However, when MC was not added, separation occurred in two weeks, and when the amount of MC added was increased to 0.5 g, the viscosity of the dispersion was 2500 CPS/20 °C, and the filtration of beads and dispersion was slow. , it was extremely difficult to handle.

Example 2 35 g of 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole having an average particle diameter of 5 μm or more as measured by a laser diffraction particle size distribution analyzer; 2.0 g of sodium dialkyl sulfosuccinate, 0.1 g of methyl cellulose (MC), 62.9 g of ion-exchanged water, and 200 g of spherical glass beads with a diameter of 1.5 mm were placed in a 500 ml beaker, stirred at high speed for 10 hours using a three-one motor, and then mixed with an 80 mesh The beads and dispersion were filtered out using a sieve. The resulting aqueous dispersion had an average particle diameter of 2.5 μm, a viscosity measured with a B-type rotational viscometer of 280 CPS/20° C., and no separation and precipitation occurred even after being left standing at room temperature for 2 months. However, when MC was not added, separation occurred in one week, and the amount of MC added was reduced to 0.5.
If the viscosity of the dispersion increases to 2000 CPS/2
At 0°C, separation of beads and dispersion by filtration was slow, making handling extremely difficult.

Example 3 30 g of 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole having an average particle diameter of 5 μm or more as measured by a laser diffraction particle size distribution analyzer; 20 g of n-octadecyl-3-(4-hydroxy-3,5'-di-tert-butylphenyl)propionate, sodium dialkylsulfosuccinate3.
0g, methyl cellulose (MC) 0.1g, ion exchange water 46.9g and spherical glass beads with a diameter of 1.5mm 2
00g was placed in a 500 ml beaker and stirred at high speed for 10 hours using a three-one motor, and the beads and dispersion were filtered through an 80 mesh sieve. The resulting aqueous dispersion had an average particle diameter of 2.5 μm and a viscosity of 280 as measured with a B-type rotational viscometer.
CPS/20°C, and no separated precipitate was produced even after being left standing at room temperature for 2 months. However, when MC was not added, separation occurred in one week, and when the amount of MC added was increased to 0.5 g, the viscosity of the dispersion was 2000 CPS/20 °C, and the filtration of beads and dispersion was slow. It was extremely difficult to handle.

Example 4 Dilauryl thiodipropionate 4 having an average particle diameter of 5 μm or more as measured by a laser diffraction particle size distribution analyzer
0g, sodium lauryl sulfate 7.0g, sodium polyacrylate 0.1g, ion exchange water 52.9g and 200g of spherical glass beads with a diameter of 1.5mm in 500ml.
The mixture was placed in a large beaker and stirred at high speed for 20 hours using a three-one motor, and the beads and dispersion were filtered through an 80-mesh sieve. The resulting aqueous dispersion had an average particle diameter of 4.5 μm, a viscosity of 390 CPS/20° C. as measured by a B-type rotational viscometer, and no precipitation occurred even after being left at room temperature for 2 months. However, when sodium polyacrylate was not added, separation occurred immediately, and when the amount of sodium polyacrylate added was increased to 0.5 g, the mixture became creamy and could not be dispersed.

Example 5 50 g of 2-(2-hydroxy-5-methylphenyl)benzotriazole with an average particle size of 5 μm or more as measured by a laser diffraction particle size distribution analyzer, 3 g of sodium lauryl sulfate, polyvinyl alcohol (with a polymerization degree of approx. 500)
0.2 g, 46.8 g of ion-exchanged water, and 200 g of spherical glass beads with a diameter of 1.5 mm were placed in a 500 ml beaker, stirred at high speed for 20 hours with a three-one motor, and
The beads and dispersion were filtered through a mesh sieve. The resulting aqueous dispersion had an average particle diameter of 1.4 μm, a viscosity of 240 CPS/20°C measured with a B-type rotational viscometer, and a
No precipitate was formed even after standing for several months. However, when polyvinyl alcohol was not added, separation occurred immediately, and when the amount of polyvinyl alcohol added was increased to 0.5 g, the viscosity increased to 1800 CPS/20°C and solidified after 22 days.

[0018]

[Effects of the Invention] As is clear from the above examples, the thermal and photooxidative deterioration inhibitor dispersion of the present invention has excellent storage stability over time, is easy to handle, and is industrially useful. .

Claims (1)

[Claims] 1. A dispersion of a thermal and photo-oxidative deterioration inhibitor, characterized in that it contains an antioxidant and/or a light stabilizer with an average particle diameter of 5 μm or less, an emulsifier, and a dispersion stabilizing aid of less than 0.5% by weight. liquid.