JPH0217575B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to aqueous polymeric microsuspensions. In one aspect, the invention relates to stabilizing these microsuspensions against various salt and mechanical conditions, while in another aspect, the invention relates to stabilizing these microsuspensions with alkyl diphenyl ether sulfonate surfactant compositions. Concerning stabilization of Jiyoung. Surfactants consisting of alkyl diphenyl ether sulfonates were known in the art. A series of such compositions are manufactured by The Dow Chemical Company under the trade name Dowfax. Typical of these compositions are mixtures containing 70% by weight or more of monoalkylated, essentially disulfonated diphenyl oxide. Both the long chain of the alkyl group and the neutralizing cation of the sulfonate group can be varied as desired. These compositions have a number of known uses, including imparting salt and mechanical stability to various aqueous polymeric microsuspensions. According to this invention, the salt and/or mechanical stability imparted to polymeric microsuspensions by mono- and dialkyl diphenyl ether sulfonate surfactant compositions is such that at least 35% by weight of the composition is at least one dialkyl improved in the case of diphenyl ether sulfonate. The surfactant used in the practice of this invention consists of at least 35% by weight, preferably at least 40% by weight, and still preferably at least 50% by weight of at least one dialkyl diphenyl ether sulfonate. These sulfonates have the general formula (wherein each R is an alkyl group and R may be the same or different, each M is hydrogen, an alkali metal ion, an alkaline earth metal ion or an ammonium ion, and each M
may be the same or different and x or y is 1, provided that in all of the general formulas () the average value of Σ(x+y) is at least 1.7, and preferably at least 1.8. and x and y are each 0 or 1).
R is preferably 4 to 18 and more preferably 10
It is an alkyl group of ~18 carbon atoms. The alkyl group of R is straight chain, and branched is cyclic, but straight and branched groups are preferred. the
M ammonium group has the general formula (R') ₃ HN where R' is hydrogen, C ₁ - C ₄ alkyl or C ₁ - _{C 4}
is a hydroxyalkyl group, and each R' may be the same or different. Typical _C1 - _C4 alkyl and hydroxyalkyl groups are methyl, ethyl, propyl, isopropyl,
Contains butyl, hydroxymethyl, hydroxyethyl, etc. Typical ammonium ionic groups are ammonium (N ⁺ H ₄ ), methylammonium (CH ₃ N ⁺ H ₃ ), ethylammonium (C ₂ H ₅ N ⁺ H ₃ ), and dimethylammonium ((CH ₃ ) ₂ N ⁺ H ₂ ), methylethylammonium (CH ₃ N ⁺ H ₂ C ₂ H ₅ ), trimethylammonium ((CH ₃ ) ₃ N ⁺ H), dimethylbutylammonium ((CH ₃ ) ₂ N ⁺ HC ₄ H ₉ ), hydroxy These include ethyl ammonium (HOCH ₂ CH ₂ N ⁺ H ₃ ) and methylhydroxyethylammonium (CH ₃ N ⁺ H ₂ CH ₂ CH ₂ OH). M ⁺ is preferably an alkali metal ion and more preferably a sodium or potassium ion. The remainder of the surfactant typically consists of at least one monoalkyl diphenylether sulfonate. This substance has the general formula ()
It has a structure similar to that sulfonate of general formula () except that it has one R group that can be attached to either nucleus like the sulfonate of . The R is ortho, meta or para to the ether oxygen. monoalkyl diphenyl ether sulfonate of not less than 65% by weight of the composition,
Preferably 60% or more and most preferably 50%
% or more. The surfactant compositions of this invention may be substantially free of monoalkyl diphenyl ether sulfonates and may be substantially 100% by weight of dialkyl diphenyl ether sulfonates. The dialkyl diphenyl ether sulfonates are known compounds and can be easily prepared and incorporated into surfactant compositions by one of a number of known methods. One well-known and accepted method is taught by USP 2990375 and consists of a series of steps,
The first step is to combine an olefin or an olefin halide, such as tripropylene, tetrapropylenes, pentapropylenes, or dotesyl bromide, with a Friedel ether such as aluminum chloride at a temperature of about 50-100°C. It consists of producing an alkyl diphenyl ether by reaction in the presence of a Crafts catalyst. The reaction mixture is washed with water to remove the catalyst, the phases are separated and the organic rich phase is distilled to obtain a fraction consisting of a mixture of mono- and dialkylated diphenyl ethers. The membership of alkyl substituents per diphenyl ether molecule can be controlled by adjusting the relative proportions of the reactants. Alternatively, the distillation can be carried out to separate the mono- and dialkylated diphenyl ethers from each other and into low- or high-boiling components, and then the mono- and dialkylated diphenyl ether fractions are divided into desired proportions. Can be combined with The mixture of mono and dialkyl diphenyl ethers is then reacted with a sulfonating agent such as chlorosulfonic acid or sulfur trioxide, while the reactants are reacted with methylene chloride,
Dissolved in an inert liquid polychlorinated aliphatic hydrocarbon solvent such as carbon tetrachloride, perchlorethylene, tetrachloroethane, ethylene dichloride, etc. The sulfonation reaction comprises an average of at least two aromatic nuclei of the dialkyl diphenyl ether sulfonate present in the reaction mixture.
This is facilitated by incorporating one sulfonic acid group into one aromatic nucleus so that 1.7, preferably at least 1.8 on average, are sulfonated. When the sulfonation reaction is complete, the mixture is neutralized and made slightly alkaline, with a PH value of 7-8 with a base such as sodium hydroxide, potassium hydroxide, amine or its aqueous soluble. Mono- and dialkyl diphenyl ether sulfonic acids are converted to their corresponding salts. The aqueous and organic phases were then separated and the sulfonate was included in the aqueous phase. The sulfonates can be mixed with small amounts of inert substances, primarily alkali sulfates such as sodium sulfate or potassium sulfate, small amounts of alkali chloride if they are neutralizing substances, and water. The presence of small amounts of these inert materials does not adversely affect the invention. Alternative processes for making dialkali diphenyl ether sulfonates and the surfactant compositions of this invention are disclosed in USP 2990375. The surfactant compositions of this invention are used in the same manner as known surfactant compositions. They can be mixed as post-additives into the polymeric microsuspension precursor prior to polymerization or into the polymeric microsuspension itself after polymerization. If added after the polymeric microsuspension is formed, the composition provides increased or improved mechanical and/or salt (electrolyte) stability. The compositions of this invention, when added to a polymeric microsuspension precursor, impart improved mechanical and/or salt stability to the final polymeric microsuspension, as well as improve the concentration of its surfactant composition. The polymeric microsuspension particles can be produced without increasing the However, post-addition is preferred in certain latex systems whose polymer solids consist primarily of hard monomers such as styrene. However, and especially in non-species systems, the surfactant added to the polymeric microsuspension precursor may be added simply by adjusting the monoalkylate:dialkylate ratio or the concentration of the surfactant composition. can be used to influence optimal particle size without increasing or decreasing the The extent to which and in which direction (larger or smaller) particle size is affected depends on several factors, including the initial loading of the surfactant and the type of polymer precursor. A stable amount of a surfactant composition is added to the aqueous polymeric microsuspension. A typical minimum amount is 0.05% and preferably 0.5% by weight based on the weight of the microsuspension.
Based on practical considerations such as convenience or economy,
The maximum amount of surfactant is 5% by weight and preferably 2% by weight. "Aqueous polymeric microsuspension" means polymer particles dispersed in an aqueous continuous phase in which the polymer is in a solid state as opposed to a viscous liquid state. These microsuspensions are sometimes known as aqueous polymer dispersions. Suitably microsuspended or dispersed particles are solid (melting point above 20° C.) thermoplastics whose collapse point is somewhat higher than their melting point. The polymers are polyolefins; polybutadiene-copolymers of 1,3 and 1,3-butadiene and copolymerizable monomers such as styrene, acrylonitrile, etc.; vinyl resins such as vinylpyridine; olefin-vinyl copolymers;
Polyamides; Epoxy resins; Homopolymers and copolymers of monovinylidene aromatic monomers; Acrylic resins; Polyesters; Polycarbonates;
Contains polyurethane, etc. Vinyl microsuspensions made from at least one vinyl monomer particularly benefit from this invention. Examples of microsuspensions include those made from styrene/butadiene, ethyl acrylate, polyvinyl chloride, polyvinyl acetate, and the like.
An example of a microsuspension that would benefit from this invention is described in US Pat. No. 4,123,403. Typical particle sizes for these microsuspensions range from 150 angstroms to 15,000 angstroms and preferably from 300 to 3,000 angstroms. The following shows specific examples of the invention. All parts and percentages are by weight unless otherwise indicated. Specific Examples Examples 1-2 and Controls A-B The microsuspensions used herein were
70 parts to 100 parts), Bensonol (Versonol)
-120 (0.0125 parts per 100 parts of monomer), trisodium salt of N-(hydroxyethyl)-ethylenediaminetriacetic acid (an organic chelating agent manufactured by Sa Dow Chemical Company) and surfactants (in the table monomer as shown
1.35 parts per 100 parts) were initially introduced into the reactor.
The contents of the reactor were heated to 80° C. and the reactor was charged with 588.9 g/hr of monomer for 3 hours and then 294.4 g/hr of monomer for 3 hours.
The monomers are 54 parts styrene, 44 parts butadiene,
Consists of 2 parts of acrylic acid and 6 parts of carbon tetrachloride.
Six hours after the monomer charge, 120.9 g/hr of aqueous mixture (15 minute aqueous prestart) was added to the reactor after 6 hours. The aqueous mixture is deionized water
28 parts, Bensonol - 0.005 parts of 120 parts, surfactant (same as used in first charge)
0.3 parts, 0.6 parts of sodium persulfate and 0.12 parts of sodium hydroxide. The reaction was run for 3 hours after the addition of the aqueous mixture was complete. Four surfactant compositions were prepared and used. The first two compositions were outside the scope of this invention, while the next two compositions were within the scope of this invention. All compositions are mixtures of two alkyl diphenyl ether sulfonates. The first composition, Control A, consisted of 100% monoalkyl diphenyl ether sulfonate. The second composition, Control B, consisted of an 80:20 mixture of mono-dialkyl diphenyl ether sulfonates.
The third and fourth compositions, Examples 1 and 2, consist of mono- and dialkyl diphenyl ether sulfonates 50:50 (Example) and 20:80 (Example 2). In each composition, the alkyl group (R) is a branched C ₁₂ tetrapropylene group, the counterion (M) is sodium, and the degree of sulfonation (Σ(x+y)) is greater than 1.7 or equal. The various tests and measurements were performed on microsuspensions made with various surfactant compositions. The details are shown in the table.

[Table] Salt stability is determined by adding 10% sodium chloride to a 25 g sample of microsuspension until the beginning of evidence of agglomeration.
Added by adding solution. Therefore, the numbers in the salt stability column of the table are based on 25 g of microsuspension added to the sample until agglomeration occurs.
Represents the number of milliliters of 10% sodium chloride.
The greater the number, the greater the stability of the microsuspension. Mechanical stability was determined by stirring a 200 g sample of the microsuspension in a Hamilton Beach mixer for 20 minutes at high speed. The microsuspension was passed through a 100 mesh (0.149 mm aperture) screen to collect the residue. Therefore, the numbers in the mechanical properties column of the table represent the number of grams of waste collected on the 100 mesh (0.149 mm aperture) screen. All controls and examples were run at substantially the same speed. The higher the number, the higher the mechanical stability of the microsuspension. A comparison of control versus example demonstrates the improved nature of this invention. Its mechanical and salt stability increases as the concentration of the dialkyl diphenyl ether sulfonate in the surfactant increases. This increase is achieved despite a decrease in the total moles of surfactant composition used. An increase in particle size is accompanied by an increase in dialkylate content in the surfactant composition.

Claims (1)

Claims: 1. A method for imparting salt and/or mechanical stability to an aqueous polymeric microsuspension by mixing the same with a mono- and dialkyl diphenyl ether sulfonate surfactant composition. , at least 35% by weight of the composition is of the general formula (wherein each R is an alkyl group and R may be the same or different, each M is hydrogen, an alkali metal ion, an alkaline earth metal ion or an ammonium ion, and each M
may be the same or different, and in all general formulas () x and y are individually 0 or 1, provided that the mean value of Σ(x+y) is at least 1.7. A method characterized in that it is at least one dialkyl diphenyl ether sulfonate. 2. The method according to claim 1, wherein M is an alkali metal ion. 3. The method of claim 1, wherein 3 R is an alkyl group of 4 to about 18 carbon atoms. 4. The method according to claim 3, wherein M is a sodium ion. 5. The method of claim 1, wherein at least 50% by weight of the composition is a compound of general formula (). 6. A method according to any one of claims 1 to 5, wherein the composition is present in an amount of at least 0.05% by weight of the microsuspension. 7. Claim 1, wherein the composition is present at least 0.5% by weight of the microsuspension.
6. The method according to any one of items 6 to 6. 8. A method according to claims 1 to 7, wherein the microsuspension comprises polystyrene or polystyrene-butadiene polymer. 9. Claims 1 to 8 in which the composition is mixed with the microsuspension as a post-additive
The method described in any of the sections. 10 Claim 1 wherein the composition is mixed with the polymeric microsuspension precursor
The method according to item 8.