METHODS FOR MAKING POLY(OXYALKYLENE) ACRYLIC POLYMERS AT HIGH SOLIDS AND LOW VISCOSITY

Abstract

The present invention provides methods of making an aqueous composition comprising polymerizing in the presence of one or more initiators at a pH of from 1 to 5 an aqueous monomer mixture of an aqueous medium and one or more acrylic or vinyl macromonomers containing an oxyalkylene chain group in the presence of one or more carboxylic acid group containing fluids chosen from a copolymerizable ethylenically unsaturated carboxylic acid, a polymeric polycarboxylic acid and mixtures thereof, to form a brush polymer-containing oxyalkylene side chain groups, wherein, the polymerizing takes place at a solids content ranging from 8 to 60 wt.%, and, combining one or more aromatic cofactors with the aqueous composition. In addition, the present invention provides aqueous compositions of brush polymers containing oxyalkylene side chain groups having more than one phase domain and a substantially reduced viscosity to enable processing with far less energy input or water waste.

Claims

1. An aqueous composition for use as a thickener and water retention aid comprising: an aqueous medium; one or more brush polymer containing oxyalkylene side chain groups comprising, in polymerized or copolymerized form, one or more acrylic or vinyl macromonomers containing an oxyalkylene chain group, and the polymerization residue of an initiator; one or more aromatic cofactors; and one or more carboxylic acid group containing fluids chosen from: an ethylenically unsaturated carboxylic acid, in copolymerized form as part of the brush polymer containing oxyalkylene side chain groups, a polymeric polycarboxylic acid, or mixtures thereof, wherein the aqueous medium is at least 90 wt.% water; and, further wherein, the composition has a pH of from 1 to 5 and has a solids content ranging from 8 to 60 wt.%.

2. The aqueous composition as claimed in claim 1, having a pH of from 1 to 4.8 and, further wherein, the composition contains substantially no salt or no added salt excluding any one or more initiators or the polymerization byproducts thereof.

3. The aqueous composition as claimed in claim 1, comprising a molar ratio of: total moles carboxylic acid, which total moles of carboxylic acids are determined as the total moles of ethylenically unsaturated carboxylic acid monomers used to make the one or more brush polymer containing oxyalkylene side chain groups plus the total moles of ethylenically unsaturated carboxylic acid monomers used to make the one or more polymeric polycarboxylic acids, and, if any polymeric polycarboxylic acids are not addition polymers, the total moles of carboxylic acid groups in the one or more polymeric polycarboxylic acids, to total moles of oxyalkylene, which total moles of oxyalkylene is determined as the total moles of the one or more acrylic or vinyl macromonomers containing an oxyalkylene chain group used to make the one or more brush polymers containing oxyalkylene side chain groups, multiplied by the average number of oxyalkylene chain groups in the total amount of acrylic or vinyl macromonomers containing an oxyalkylenechain group, as reported by the macromonomer manufacturer, ranging from 0.1:1 to 10:1.

4. The aqueous composition as claimed in claim 3, wherein the molar ratio of total moles of carboxylic acid to total moles of oxyalkylene ranges from 0.2:1 to 5:1.

5. The aqueous composition as claimed in claim 1, comprising a storage stable aqueous mixture or additive concentrate having a solids content ranging from 10 to 40 wt.%.

6. A method of making an aqueous composition comprising: polymerizing in the presence of one or more initiators at a pH of from 1 to 5 an aqueous monomer mixture of an aqueous medium and one or more acrylic or vinyl macromonomers containing an oxyalkylene chain group in the presence of one or more carboxylic acid group containing fluids chosen from a copolymerizable ethylenically unsaturated carboxylic acid, a polymeric polycarboxylic acid, or mixtures thereof, to form a brush polymers containing oxyalkylene side chain groups, wherein the aqueous portion of the aqueous monomer mixture comprises at least 90 wt.% of water, and, further wherein, the polymerizing takes place at a solids content ranging from 8 to 60 wt.%.

7. The method as claimed in claim 6, wherein, in the polymerizing the aqueous monomer mixture has a pH of from 1 to 4.8; and, further wherein, the aqueous monomer mixture contains substantially no salt or no added salt excluding any one or more initiators.

8. The method as claimed in claim 6, wherein in the polymerizing the aqueous monomer mixture, a molar ratio of: total moles carboxylic acid, determined as the total moles of ethylenically unsaturated carboxylic acid monomers used in the polymerizing the one or more macromonomers containing an oxyalkylene chain group plus the total moles of ethylenically unsaturated carboxylic acid monomers used to make the one or more polymeric polycarboxylic acids, and, if any polymeric polycarboxylic acids are not addition polymers, the total moles carboxylic acid groups in the one or more polymeric polycarboxylic acids, to total moles of oxyalkylene, determined as the total moles of acrylic or vinyl macromonomer polymer-containing oxyalkylene side chain groups used to make the one or more brush polymer-containing oxyalkylene side chain groups multiplied by the average number of oxyalkylene chain groups in the total amount of acrylic or vinyl macromonomers containing an oxyalkylene chain group, as reported by the macromonomer manufacturer, ranges from 0.1:1 to 10:1.

9. The method as claimed in claim 6, wherein the total amount of the acrylic or vinyl macromonomer containing an oxyalkylene chain group ranges from 20 to 100 wt.%, based on the total weight of monomers used to make the brush polymer- containing oxyalkylene side chain groups.

10. The method as claimed in claim 6, wherein the polymerizing takes place at a solids content of from 10 to 45 wt.%.

11. The method as claimed in claim 6, wherein the aqueous monomer mixture comprises as the one or more acrylic or vinyl macromonomers a C.sub.1 to C.sub.4 alkoxy poly(C.sub.2 to C.sub.4 alkylene glycol) (meth)acrylate.

Description

EXAMPLES

[0079] The following examples illustrate the present invention. Unless otherwise indicated, all parts and percentages are by weight and all temperatures are in °C and all preparations and test procedures are carried out at ambient conditions of room temperature (23° C.) and pressure (1 atm). In the examples and Tables 1, 2, and 3 that follow, the following abbreviations were used: RDP: Redispersible Polymer Powder; MPEGMA: Methoxypoly(ethylene glycol) methacrylate; MAA: Methacrylic acid; AA: Acrylic acid; MMA: Methyl methacrylate; EO: Ethylene oxide.

[0080] All chemicals aside from AA, MMA and MAA were purchased from Sigma-Aldrich and used with no further purification.

[0081] Synthesis Example 1: Polymeric Polycarboxylic Acid A 50 wt.% solids poly(acrylic acid) additive was synthesized in a 1 L round bottom flask. 103.5 g of water was added, stirred at 170 rpm, and heated to 73° C. under a flow of nitrogen gas. Then 1.25 g of a 0.15 wt% iron (ll) sulfate solution and 2.83 g of sodium meta-bisulfite dissolved in 5.94 g of water were added. Next, feeds of 40.76 g sodium meta-bisulfite dissolved in 63.31 g of water, 150 g of AA rinsed with 3.5 g of water, and 0.57 g of sodium persulfate dissolved in 8.5 g of water were started simultaneously and fed over 70, 90, and 95 minutes, respectively. The temperature gradually rose to 75° C., and after the end of the sodium persulfate solution feed, the temperature was held at 75° C. for 15 additional minutes. Following this hold, 0.21 g of sodium persulfate dissolved in 10.0 g of water was added over 10 minutes, and then the reactor was held at 75° C. for an additional 20 minutes. After cooling to 60° C., 4.8 g of 35 wt% hydrogen peroxide was added over 2 minutes, and then the reactor was held at 60° C. for an additional 10 minutes. Finally, the reactor was cooled to room temperature.

[0082] Synthesis Example 2: Brush Polymer Compositions Containing Oxyalkylene Side Chain Groups and A Separate Polymeric Polycarboxylic Acid The brush polymers of Comparative Example 1 and Inventive Examples 1, 2, and 3 were synthesized in a 300 mL flat bottom flask and stirred with an impeller at 120 rpm. 12.8 g of MPEGMA-500 (having an average of 9 EO units and a molar mass of 500 g), 2.2 g of MMA, and water and 50 wt% polyacrylic acid solution from synthesis Example 1, above, were added to the reactor. The solution was heated to 70° C. under nitrogen for 1 hr. Next, a solution of 0.030 g of ammonium persulfate in 1.875 g of water was added and rinsed in with an additional 1.875 g of water. The temperature was maintained at 70° C. for 2 hr, and then an additional solution of 0.030 g of ammonium persulfate in 1.875 g of water was added and rinsed in with an additional 1.875 g of water. The temperature was again maintained at 70° C. for 2 hr and then cooled to room temperature. The compositions of this synthesis example 2 and a polymeric polycarboxylic acid are presented in Table 1, below.

[0083] Synthesis Example 3: Brush Polymer Compositions Containing Oxyalkylene Side Chain Groups and A Carboxylic Acid in Copolymerized Form The brush polymer of Inventive Example 4 was synthesized in a 1 L round bottom flask. 451.1 g of water, 21.3 g of MPEGMA-500, and 3.7 g of MAA were added to the reactor, and each monomer was rinsed in with an additional 6.2 g of water. The solution was heated to 70° C. under nitrogen for 1 hr. Next, a solution of 0.050 g of ammonium persulfate in 3.124 g of water was added and rinsed in with an additional 3.124 g of water. The temperature was maintained at 70° C. for 2 hr, and then an additional solution of 0.050 g of ammonium persulfate in 3.124 g of water was added and rinsed in with an additional 3.124 g of water. The temperature was again maintained at 70° C. for 2 hr and then cooled to room temperature. The compositions made by this synthesis example 3 are presented in Table 3, below.

[0084] The brush polymer of Inventive Example 5 was synthesized in a 1 L round bottom flask. 401.6 g of water, 42.5 g of MPEGMA-500, and 7.5 g of MAA were added to the reactor, and each monomer was rinsed in with an additional 12.5 g of water each. The solution was heated to 70° C. under nitrogen for 1 hr. Next, a solution of 0.100 g of ammonium persulfate in 6.249 g of water was added and rinsed in with an additional 6.249 g of water. The temperature was maintained at 70° C. for 2 hr, and then an additional solution of 0.100 g of ammonium persulfate in 6.249 g of water was added and rinsed in with an additional 6.249 g of water. The temperature was again maintained at 70° C. for 2 hr and then cooled to room temperature. The compositions made by this synthesis example 3 are presented in Table 3, below.

TABLE-US-00001 Compositions From Synthesis Example 1 Made With Poly(Acrylic Acid) Additive Example AA:EO (mol/mol) Water (g) Poly(acrylic acid) solution (g) Total Solids (wt.%) Comparative 1* 0 128.0 0 8.50 wt% 1 0.5 119.6 16.7 13.10 wt% 2 1 111.3 33.4 17.40 wt% 3 1.5 103.0 50.0 21.85 wt% *- Denotes Comparative Example.

[0085] Test Methods: The following test methods were used:

[0086] Solids Content: The solids content was measured by weighing the indicated amount of a given composition and then evaporating the water in a 60° C. oven. Solids contents for the indicated example are set forth in Tables 2 and 3, below.

[0087] Solution Viscosity: Solution viscosities were measured with a Brookfield viscometer with the spindle indicated at frequencies of 10 and 30 rpm, as indicated. The solution viscosity results for the indicated example are set forth in Tables 2 and 3, below.

TABLE-US-00002 Brookfield Viscosity Data For Examples Made With Poly(Acrylic Acid) Polymer Example AA:EO (mol/mol) Total Solids (wt.%) Spindle Frequency (rpm) Viscosity (cP) Frequency (rpm) Viscosity (cP) Comparative 1* 0 8.50 65 10 19000 30 11000 1 0.5 13.10 63 10 1000 30 932 2 1 17.40 63 10 160 30 148 3 1.5 21.85 62 10 60 30 63 *- Denotes Comparative Example.

TABLE-US-00003 Brookfield Viscosity Data For Examples With Methacrylic Acid As Comonomer. Example Comonomer Total Solids (wt.%) Spindle Frequency (rpm) Viscosity (cP) Frequency (rpm) Viscosity (cP) Comparative 1* 15 wt.% MMA 8.50 65 10 19000 30 11000 4 15 wt.% MAA 4.55 61 10 - 30 5.8 5 15 wt.% MAA 8.55 61 10 130.2 30 93.8 *- Denotes Comparative Example.

[0088] As is illustrated in the data listed in

[0089] Table 2, above, the Inventive Examples made in the presence of the polyacrylic acid contain 10 wt% MPEGMA copolymer solids content but yield a much lower viscosity than that of the Comparative Example. This reduction in viscosity is proportional to the amount of poly(acrylic acid) added. It is important to note that all the Examples and Comparatives have the same MPEGMA copolymer content. However, the overall solids content increased with the amount of the poly(acrylic acid) added; despite this, the measured viscosity decreased with the amount of the poly(acrylic acid) added. Finally, Table 3, above, lists the viscosities of Inventive Examples 4 and 5, which comprise an acrylic brush polymer-containing oxyalkylene side chain groups and, in copolymerized form, MAA as the comonomer. The compositions of Examples 4 and 5 exhibited dramatically reduced viscosities, even at the same solids content as in Comparative Example 1.