JPH04239592A - Oxidation preventive dispersion - Google Patents

Abstract

PURPOSE:To obtain the title highly concentrated dispersion excellent in storage stability, causing no sedimentation and phase separation, by dispersing in water triethylene glycol bis[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate] and each specific emulsifier and dispersion stabilizing auxiliary. CONSTITUTION:The objective dispersion can be obtained by dispersing in an aqueous medium (A) 25 to <60wt.% of triethylene glycol bis[3-(3-t-butyl-4- hydroxy-5-methylphenyl)propionate] with an average particle size of <=5 (pref. <=3)mum, (B) as emulsifier, 0.1-10 (esp. 0.5-5)wt.% of an alkali (alkaline earth) metal salt or ammonium salt of alkyldiphenyl ether disulfonic acid, alkali (alkaline earth) metal salt of dialkylsulfosuccinic ester, or polyoxyethylene alkyl ether, and (C) as dispersion stabilizing auxiliary, <0.5 (esp. 0.05-0.4)wt.% of sodium polyacrylate or methyl cellulose.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to triethylene glycol bis[3-(3-tert-butyl-
4-Hydroxy-5-methylphenyl)propionate dispersion.

0002

[Prior Art] Resins such as vinyl chloride resins, ABS resins, and MBS 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, and in order to uniformly disperse them in the resin, it is preferred to add them while the polymer is in a solution or slurry state during polymerization. Vinyl chloride resin, ABS resin, MBS
Triethylene glycol bis[3-(3
-Tertiary butyl-4-hydroxy-5-methylphenyl) propionate] is frequently used as an antioxidant because it prevents initial discoloration and improves heat resistance in small amounts.
Due to its powder nature and water repellency, it is difficult to automatically add a predetermined amount to the polymer, especially in the molten or slurry state during polymerization, when the system is usually under pressure. Therefore, it is difficult to press fit quantitatively. For this reason, conventional methods have been taken such as adding it by dissolving it in a suitable solvent, or melting it above the melting point and emulsifying and dispersing it.
The method of dissolving in an organic solvent is not a preferable method because it increases the COD in waste water, especially when carrying out suspension polymerization in an aqueous medium, and the method of melting and emulsifying and dispersing it is not a preferable method, especially when carrying out suspension polymerization in an aqueous medium. There are difficulties in dispersing the liquid, etc.
At present, this is not a desirable method.

0003

[Problems to be Solved by the Invention] Previously, there has been a method in which a powdered antioxidant is dispersed in water using an emulsifier or a suspending agent alone or in combination with an emulsifying agent or a suspending agent to form an emulsion and then added. is proposed.

[0004] JP-A-60-63274 proposes an antioxidant dispersion characterized in that an antioxidant containing 99% by weight or more of particles with a Stokes diameter of less than 10 μm is dispersed in water together with an emulsifier. ing. In this dispersion, the amount of antioxidant with a Stokes diameter of 10 μm or more is 1
It is stated that if the weight percentage is exceeded, those with a true specific gravity of more than 1 will settle, and those with a true specific gravity of less than 1 will undergo phase separation if left to stand after dispersion. However, it is technically and industrially difficult to produce an antioxidant dispersion containing 99% by weight or more of particles with a Stokes diameter of less than 10 μm. Antioxidant dispersions with excellent storage stability that do not cause phase separation are desirable.

[0005] Also, Japanese Patent Application Laid-open No. 60-186547,
In JP-A No. 61-159483, the antioxidant is
Antioxidant dispersions have been proposed consisting of 70% by weight, 0.1 to 10% by weight of emulsifier or silicone, 0.5 to 10% by weight of suspending agent, and the remainder water. In these dispersions, the proportion of the suspending agent is preferably 0.5 to 10% by weight, and it is stated that if it is less than 0.5% by weight, the storage stability deteriorates and is not preferable. The use of is not preferable because it increases the COD of the wastewater and increases the manufacturing cost. By the way, triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate] has a true specific gravity greater than 1, so when producing a dispersion, it is especially important to avoid sedimentation. It is necessary to select an emulsifier that does not cause phase separation and does not increase viscosity.

The object of the present invention is to obtain triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-
The object of the present invention is to provide a highly concentrated aqueous dispersion of methylphenyl propionate which does not cause sedimentation or phase separation and has excellent storage stability, which is technically easy and industrially inexpensive.

[0007]

[Means for Solving the Problems] As a result of intensive studies in order to solve the above problems, the present inventors have found that a specific emulsifier is used alone or in combination with a dispersion stabilizing agent to disperse it in water. The antioxidant triethylene glycol bis[3-(3
-Tertiary butyl-4-hydroxy-5-methylphenyl)propionate] It was discovered that an aqueous dispersion can be obtained, and the present invention was completed.

That is, the present invention uses triethylene glycol bis[3(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate] having an average particle diameter of 5 μm or less, and an alkali metal alkyl diphenyl ether disulfonic acid as an emulsifier. 0 as salts, alkaline earth metal salts or ammonium salts, and dispersion stabilizing aids
．． less than 5% by weight of sodium polyacrylate; alkali metal or alkaline earth metal salts of dialkyl sulfosuccinates as emulsifier and less than 0.5% by weight of methylcellulose as dispersion stabilizing aid; or polyoxyethylene alkyl as emulsifier The present invention relates to an antioxidant dispersion characterized by containing an ether.

[0009] The antioxidant aqueous dispersion according to the present invention refers to a dispersion in which the antioxidant concentration is at least 25% by weight or more and less than 60% by weight, but is not limited to this concentration. . However, in general, if it exceeds 60% by weight, the fluidity becomes extremely poor and dispersion becomes impossible, which is undesirable, and if it exceeds 25% by weight, the economic merit decreases, so it is not preferred. The average particle diameter of the antioxidant dispersed in the aqueous medium according to the present invention is 5 μm or less, preferably 3 μm or less in order to maintain storage stability. However, even if some particles with a particle size of 10 μm or more are included, there is no effect. The average particle diameter here refers to the particle diameter when the volume reaches 50% (volume average diameter).

[0010] The alkali metal salts, alkaline earth metal salts or ammonium salts of alkyldiphenyl ether disulfonic acids, the alkali metal salts or alkaline earth metal salts of dialkyl sulfosuccinates, or the polyoxyethylene alkyl ethers used as emulsifiers in the present invention. "Alkyl" is a linear or branched alkyl having 1 to 22 carbon atoms, and alkali metal salts include sodium salts, potassium salts, etc., and alkaline earth metal salts include magnesium salts, calcium salts, etc. means. More specifically, sodium alkyl diphenyl ether sulfonate (trade name: Perex SS-H, manufactured by Kao), ammonium alkyldiphenyl ether sulfonate (trade name:
Nucol 271-NH, manufactured by Nippon Nyukazai), sodium dioctyl sulfosuccinate (product name: Perex OT)
(manufactured by Kao), polyoxyethylene lauryl ether, etc. In the present invention, sodium polyacrylate used as a dispersion stabilizing aid preferably has a molecular weight of 30,000 to 40,000.

The proportion of the emulsifier in the dispersion is preferably 0.1 to 10% by weight, and 0.5 to 5% by weight based on the actual active ingredient.
is even more preferable. If the proportion of the emulsifier in the dispersion exceeds 10% by weight, the COD in the waste water will increase, which is not preferable. The proportion of the dispersion stabilizing aid in the dispersion is less than 0.5% by weight, preferably from 0.05 to 0.4% by weight. 0.5
If it exceeds % by weight, the viscosity becomes high, making it difficult to handle, and sedimentation and phase separation are likely to occur, which is not preferable. Although there are no particular restrictions on the water used in the dispersion, it is preferable to use deionized water or distilled water.

The triethylene glycol bis[3-( An aqueous dispersion of 3-tert-butyl-4-hydroxy-5-methylphenyl)propionate] can be obtained, but the equipment used is required to obtain a powdery oxidized solution with an average particle size of 5 μm or less. It is sufficient that the inhibitor is substantially uniformly dispersed in water using a specific emulsifier alone or together with a specific emulsifier and a dispersion stabilizing aid, and various known methods such as a batch method or a continuous method can be used. For example, Bowl Mill, Tube Mill, Premier Colloid Mill, Shallotte Colloid Mill,
It can be manufactured using a dye mill, a visco mill, a sand grinder, etc.

[0013]

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

Example 1 Triethylene glycol bis[3-
(3-tertiary butyl-4-hydroxy-5-methylphenyl) propionate] 50 g, sodium dioctyl sulfosuccinate (trade name: Perex OTP) 3 g, methyl cellulose (MC) 0.2 g, ion-exchanged water 46.
8 g and 150 g of spherical glass beads with a diameter of 1.5 mm were placed in a 300 ml beaker, 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.
Particle size measured with a B-type rotational viscometer at 2μm is 700CPS
/20°C, and no separated precipitate was formed even after being left at room temperature for 2 months.

Example 2 In place of the sodium dioctyl sulfosuccinate in Example 1, 6.5 g of ammonium alkyldiphenyl ether disulfonate (trade name: Nucor 271-NH) was used (
The dispersion was wet-milled in the same manner as in Example 1 at a slurry concentration of 50%, except that 0.1 g of sodium polyacrylate was used instead of methyl cellulose, and the active ingredient amount was 3.0 g, and the rest was water. The particle size was 2.3 μm, and the viscosity measured with a B-type rotational viscometer was 700 CPS/20° C., and no separation and precipitation occurred even after standing at room temperature for 2 months.

Example 3 Example 1 with a slurry concentration of 50%, except that 2.0 g of polyoxyethylene lauryl ether was used instead of sodium dioctyl sulfosuccinate in Example 1, and methyl cellulose as a dispersion stabilizing agent was not used. The dispersion liquid wet-pulverized by the same method as in 1 had an average particle size of 2.8 μm, a viscosity measured with a B-type rotational viscometer of 300 CPS/20°C, and no separation and precipitation occurred even after being left standing at room temperature for 2 months. Ta.

Example 4 In place of sodium dioctyl sulfosuccinate in Example 1, 6 g of sodium alkyl diphenyl ether sulfonate (trade name: Perex SS-H) (3 g of active ingredient) was used.
, others are water), except that 0.3 g of sodium polyacrylate was used instead of methylcellulose.The slurry concentration was 50.
%, the dispersion wet-milled in the same manner as in Example 1 had an average particle diameter of 2.2 μm and a viscosity of 680 CPS/20°C measured with a B-type rotational viscometer, and even after being left at room temperature for 2 months. No separated precipitate was formed.

Comparative Example 1 Slurry concentration was 50, except that 2.0 g of sorbitan monolaurate was used instead of sodium dialkyl sulfosuccinate in Example 1, and methylcellulose was not used.
% was wet-pulverized in the same manner as in Example 1, but the resultant mixture became non-uniform and could not be dispersed.

Comparative Example 2 In place of sodium dioctyl sulfosuccinate in Example 1, 3.0 g of ammonium alkyldiphenyl ether disulfonate (trade name: Nucor 271-NH) was used (
Type B of a dispersion obtained by wet-pulverizing 1.4 g of the active ingredient (the rest being water) in the same manner as in Example 1 at a slurry concentration of 50%, except that 5.0 g of sodium polyacrylate was used instead of methylcellulose. The viscosity measured with a rotational viscometer was 1500 CPS/20° C. and was viscous. Moreover, phase separation occurred on the 9th day at room temperature.

Comparative Example 3 Slurry concentration was 50% except that 3 g of sodium dialkyl sulfosuccinate and 0.2 g of polyvinyl alcohol were used.
The dispersion wet-pulverized in the same manner as in Example 1 was
Phase separation occurred on the 9th day at room temperature.

Comparative Example 4 Wet pulverization was carried out in the same manner as in Example 1 at a slurry concentration of 50%, except that 6.5 g of ammonium alkyl diphenyl ether disulfonate (active ingredient amount: 3 g, others were water) and 1 g of sodium polyacrylate were used. The resulting dispersion underwent phase separation two weeks after production.

[0022]

Effects of the invention: Combinations of antioxidant triethylene glycol bis[3-(3-tertiary butyl-4-hydroxy-5-methylphenyl)propionate] with specific emulsifiers and dispersion stabilizing aids, or By using the emulsifier alone, a dispersion having an average particle diameter of 5 μm or less and a low viscosity can be obtained. This dispersion does not undergo sedimentation or phase separation for a long period of time, and has excellent storage stability.

Claims (1)

[Claims] 1. Triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate] having an average particle diameter of 5 μm or less, and an alkali metal salt of alkyl diphenyl ether disulfonic acid as an emulsifier. Alkaline earth metal or ammonium salts and less than 0.5% by weight of sodium polyacrylate as a dispersion stabilizing aid; alkali metal or alkaline earth metal salts of dialkyl sulfosuccinates as an emulsifier and a dispersion stabilizing aid. 0.5 as agent
An antioxidant dispersion characterized in that it contains less than % by weight of methylcellulose; or polyoxyethylene alkyl ether as emulsifier.