CA1259733A - Method of rapidly dissolving polymers in water - Google Patents
Method of rapidly dissolving polymers in waterInfo
- Publication number
- CA1259733A CA1259733A CA000467149A CA467149A CA1259733A CA 1259733 A CA1259733 A CA 1259733A CA 000467149 A CA000467149 A CA 000467149A CA 467149 A CA467149 A CA 467149A CA 1259733 A CA1259733 A CA 1259733A
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- polymer
- water
- suspension
- particles
- liquid carrier
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Abstract
Abstract of the Disclosure Water-soluble polymers are rapidly dissolved in water by dispersing finely divided particles of the polymer into a liquid carrier in which the polymer is insoluble to form a suspension. The suspension is then added to water in order to release the polymer into the water as discrete particles that rapidly dissolve. The polymer particles are prepared by cryogenic grinding, or another non-molecular destructive process.
Description
~ ~:5~3733 Method of Rapidly Dissolving Polymers in Water BACI~GROUND OF T~I~ INVENTION
Field of the Invention This invention relates to water~soluble polymers and, more particularly, to a method of rapidly dis-solving such polymers in water.
Description of the Prior Art The use of solutions of water-soluble polymers in thickening and flocculating applications is well known ~uch applications include the clarification of aqueous solutions in papermaking, and in treatment of sewage and industrial wastes. Such solutions of polymers are also useful as stabilizers for drilling muds, and in the secondary recovery of petroleum by waterflooding.
Although these polymers are most often available commercially as powders or as finely divided solids, they are most frequently utilized in aqueous solutions.
This necessitates that the solid polymer materia' be dissolved in water. Although the various polymers are more or less soluble in water, difficulty is often experienced in preparing aqueous polymer solutions because of their slow dissolution and because the solid polymer is not readily dispersible in water.
Furthermore, dispersion of solid polymers in water is hindered by their tendency to clump or remain as agglomerates on contact with water. Lumps of solid polymer immediately form by the encapsulation of undissolved solids in an outer coating of water-wet polymer which retards the penetration of additional 12~;i9~3 watcr into the a~glomeratc. Although many of these lumps arc eventually dissolved by continued agitation, it is frequently impractical to agitate the solution for a sufficiently long period to obtain complete dissolution.
The foregoing problems are described in U.S.
patents Re. 2~,474 (July 8, 1974) and Re. 28,576 ~October 21, 1975) issued to Anderson et al.
The above-identified Anderson et al reissue patents describe a method of rapidly dissolving water-soluble polymers in which a polymer is dispersed lnto a water-in-oil emulsion, which emulsion is then inverted in water to release the polymer into solution. The Anderscn et al disclosures require an oil-to-water ratio 15 between 5:1 and 1:10.
Accordins to the Anderson et al disclosures, emulsions containing between 5 and 75 weight percent polymer dispersed therein can be prepared and inverted into aqueous solution. However, it has been found in practice that the upper limit of the polymer content of an emulsion made according to the Anderson et al process is much lower than 75 weight percent, and usually is in the 10-35 weight percent range, depending upon the characteristics of the particular emulsion.
Further, the Anderson et al system, in practice, requires substantial amounts (e.g. 20 wt. ~, or more, based on oil) of an emulsifier in the oil/water/polymer emulsion to provide a.stable product.
125~3~33 SUMMARY OF THE INVENTION
-The invention seeks to overcome one or more of the problems described above.
The invention as broadly claimed in one aspect pertains to a method of rapidly dissolving a water soluble polymer or gum in water which comprises the steps of preparing finely-divided particles of the polymer or gum by comminuting the polymer or gum under substantially non-molecularly destructive conditions, dispersing the particles in a substantially water-free liquid carrier in which the polymer or gum is substantially insoluble to form a suspension, and adding the suspension to water with sufficient mixing to disperse and rapldly dissolve the particles in the water.
A preferred polymer is a polyacrylamide polymer, and the finely-divided particles of polyacrylamide are prepared by comminuting the polymer under cryogenic grinding conditions.
The suspension may be added to water in the presence of an emulsifier or a surfactant. Alternatively, an emul-sifier may be added to the liquid carrier before additionof the polymer or gum to the carrier~ The liquid carrier may be soluble or insoluble in water.
The polymer or gum particles are prepared by a comminution process which does not degrade the molecular structure of the polymer or gum. Only very low levels of emulsi~ier and/or surfactant, or none at all, are required to provide a stable product.
Other aspects and advantages will be apparent from the following detailed description.
DETAILED DESCRIPTION OF THE INVENTION
. _ . .
The Water Soluble Polymers These polymers are well known in the art and have been described in numerous publications and patents. They include, but are not limited to, naturally occurring galactomannan gums such as guar and locust bean gums, . l . .
~2S~3~3~
alginate salts, biologically produced polymers (e.g.
~anthan gum), polyethylene o~ides, water soluble condensation polymers, and vinyl addition polymers such as polyacrylamides and copolymeric derivatives of acryIamide with, for example, acrylic acid, m~leic anhydride, acrylonitrile, styrene, allyl or diallyl amines or dimethylaminoethylmethacrylate (D~EM). Such polymers may be nonionic, anionic or cationic.
The~-gums are well-known water-soluble polymers, and include those described in Volume lO of the En-cyclopedia of Chemical Technology, 2nd Edition, Interscience Publishers, 1966.
The molecular weight of the polymers described above may vary over a wide range, e.g. between about 10,000-25,000,000, and molecular weight is not a - critical parameter in this invention. The invention finds-~its greatest usefulness in preparing aqueous solutions or dispersions of these polymers and is particularly useful with respect to acrylamidé polymers, the molecular weights of which are in excess of 1 million.
` Polymers havin~ relatively high molecular weights previously were dissolved in water only with difficulty and tended to form extremely viscous solutions at relatively low concentrations. The polymers may be produced by any suitable me~hod of conducting polymerization reactions. Thus, solution, suspension or emulsion polymerization techniques may be used.
As used herein, the term "polymer" is`understood to include polymers and gums which are soluble in water to a significant degree. The polymers are solid, but may have a substantiàl water content. ~
. ~ ~
.
~ ~ ~9~3 The invention i5 capable of rapidly producing aqueous solutions of water soluble synthetic or natural polymers having polymer concentrations within the ranye of 0.1-10% by weight, with preferred concentrations within the range of 0.2-2.0~ by weight.
The Commlnution Process The rate of polymer dissolution in water is a function of surface aréa and, consequently, particle size. Polymers produced by most manufacturing processes are in the form of powders or lump-like agglomerates.
Largeiparticle sizes minimize handling and dusting problèms and reduce the formation of gel particles during dissolution in water. However, large prarticle size~increases dissolving time when dry particles are added dlrectly to water.
Therefore, it is desirabLe that the particles be comminuted by grinding, abrading or slicing so as develop the large surface area which promotes rapid dissolution when the polymer particles subsequently contact water. The preferred particle size of the polymer or gum is determined by the desired improvement in dissolùtion rate in water and will genera~lly be less than 100 microns and preferably less than 7~0 microns.
~ - Small particle size also promotes suspension stability.
Many of the polymers amenable to this process are subject to molecular degradation by heat generation during comminution. For such heat sensitive polymers, comminution without molecular degradation may be achieved through cryogenic grinding, such as by the use of carbon dioxide or liquid~nitrogen to reduce the temperature of the polymer prior to and/or during the grinding or sliclng process. Certain polymers that .
,, ' ' , - .
6 ~5~733 become plastic or sticky at temperatures developed in ambient temperature grinding processes can also benefit ~rom cryogenic grinding.
Such cryogenic processes employ pulverizing equipment such as that marketed by Pulverizin~ ~achinery Company of Summit, NJ under the trademark "~ikroPul".
Comminuting equipment that employs a slicing action, such as that sold by Urschel Laboratories of Valparaiso, IN under the trademark "Comitrol" may be additionally employed to further reduce particle size in the polymer suspension itself. The comminuting process and equipment are chosen to protect the polymer from significant molecular degradation and to produce the desired dissolution rate when the polymer suspension is introduced into water with mixing.
The Suspension From a commercial standpoint it is beneficial that the suspension of polymer be stable so that agitation of the stored suspension is minimal or not required, and that polymer concentration be`as high as possible to minimize~freight costs. Suspensions as high as about 70-75 wt.~ polymer solids may be produced according to this invention, depending on particle size, carrier viscosity and the effect of suspending or dispersing agents on suspension viscosity. The preferred range of polymer solids in the suspension is about 50g~-70gO by weight. Suspension stability is enhanced by relatively fine comminution of the polymer or gum and by a high viscosity li~uid carrier. Additionally the carrier may be treated with suitable thickening, dispersing, suspending or viscosity modifying agents such as those well known in the art.
..
. .
- . - , -. .
~2~73~
A particularly advanta~eous method of increasing stability with hydrocar~on oil carriers is to add an oil-in-~ater emulsifier such as the isooctylphenoxypo1yethoxyethanol product sold by ~ohm &
Haas under the trademark "Triton X-100." When this oil-in-water emulsi~ier is added to a hydroc~rbon carrier it performs the dual functio~s of increaslng suspension stabili~y and emulsifying the hydrocarbon in the water in which the polymer is ~o subsequently dissolve, thus speeding dissolution of the polymer by exposing oil-free polymer surfaces to the water.
The polymer must not be soluble in the liquid carrier, and the carrier should be substantially water-free. However, the liquid carrier may be either soluble or insoluble in water.
Since the liquid carrier is substantially water-~ree, a water-in-oil emulsion is not formed, in contrast to the process o Anderson et al reissue patents 28,474 and 28,576, identified above. Although the solid polymer may have a substantial water content, this water content does not result in the formation of a water-in-oil emulsion.
Suitable hydrocarbon oil carriers include, but are not limited to, parif~in-based oils such an Conoco's LOPS (low order para~f~n solvent) and Exxon's Faxam.
Exxon's Isopar M, a deodorized high purity isoparaffinic material, is also suita~le, as are the hydrocarbon liquids disclosed .in Anderson et al~ Re. 28,474 and 28,576.
Water-soluble or water-dispersible carriers in which the polymer is insoiuble under practical conditions may also be used in producing ~he polymer suspension. In the case wherein the liquid c~rrier is * trade mark ~2~ 3 water soluble, no surfactant is needed. ~xamples of such carriers include, but not limited to, higher alcohols, glycols and glycol ethers.
Dissolving The Polymer When a polymer-containing suspension of the type described herein is dispersed in water the polymer rapidly dissolves in the water. The polymer con-taining suspension will produce a water solution in a very short time when compared to the amount of time required to dissolve the conventional solid form of the polymer.
The polymer-containing suspension may be dispersed in water by any suitable means. Where a ~ater insoluble carrier is used, the most convenient means is to use a surfactant present in either the polymer containing suspension or the water in which the polymer is to be dissolved. The surfactant causes the carrier to rapidly emulsify in the water (forming an oil-in-water emulsion), thus expediting formation of the aqueous solution of the polymer. When this technique is used to invert the polymer-containing suspension to an aqueous solution the amount of surfactant present in the water may vary over a range of 0.01~ to 30% based on polymer. Good conversion often occurs within the range of 1.0~ to 8~ based on carrier.
The preferred surfactants for use with a polymer suspension in a hydrocarbon liquid carrier are hydrophilic and water soluble. Any anionic, cationic or nonionic hydrophilic compound can be used as the surfactant although it is~best to choose a surfactant whose ionic properties do not react with those of the polymer in solution.
. .
.
9 ~2~ 733 In addition to using water-soluble surfactants with hydrocarbon carriers, other surfactants such as silicones, clays and the like may be used since in certain instances they tend to emulsify a hydrocarbon carrier even though they are not themselves water-soluble.
By the use of this process different polymers may he com~ined into a single suspension so that when the polymers of the suspension are dissolved in water as a co-solution the technical performance of the mixture is enhanced. Such combinations include, but are not limited to, nonionic polyacrylamide with either anionic or cationic polyacrylamide copolymers, anionic poly-acrylamide copolymer with biopolysaccharide, poly-ethylene oxide with nonionic polyacrylamide, poly-ethylene oxide with cationic or anionic polycrylamide copolymers, or biopolysaccharide with galactomannan gums.
Examples Examples 1-26 To illustrate the invention, Examples 1-26 are summarized below in the Table. A variety of suspensions were prepared containing different water-soluble polymers and gums and using differing types of liquid carriers. The suspensions were then converted to polymer solutions in water using different conversion techniques and the time for polymer dissolution was compared to that for dissolution of the dry polymer or gum in its commercially available form. In all cases significant reductions in dissolving time were noted and the usual problems associated with handling and dis-persing dry polymer or gum were eliminated.
...
.
.
- . -.
-.
`` ~2597~:3 In those Examples in which the liquid carrier was ahydrocarbon oil, the hydrocarbon oil was a mixture comprising #2 diesel oil (50~) and Faxa~Z2 (S0~).
(Faxam~22 is a general purpose para~fin based oil marketed by Exxon.) In those Examples in which a surfactant was present, ~he sur~actant was Triton X-100 and was present in the suspension or water in an amount calcula~ed to give a nominal 2 wt % surfactant content, based on product. Where an emulsifier was used, the emulsifier was Triton X-100 , and was present in the suspension in an amount calculated to give an emulsifier concentration of about 2 wt %, based on suspension.
In Example 26, a small amount (about 1% by weight, based on suspension) Bentone SD-l ~a clay dispersant sold by NL Industries) was added to the suspension in order to enhance stability.
All percentages of carrier and polymer or gum are based on the total suspension. In each Example, sufficient suspensio~ was mixed with water to give an aqueous solution polymer concentration of about 0.2 wt %.
* trade mark ,. ~
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. ` ' . ,, ' '.
~ ~ I --~ ~`0~ N N I N I ~1 I ~I t ~ `1 I t~l I ~1 1 N I t`J I N
,~ ,~ o ~~ 8,~ o ,~ u~ o u~ 8 ~ o u~ o ,~ o ~ o 1 l~i N '~ 8 o o v 8 v A V A V ~ V g V A V I V V
" .~
~ m m m m m ~1 m~! m ~ m ~ m ~ m .~
8 ~ o~o~o~
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8 ~ ~ ~ ~ ~ o ", o ", o " o U~ o u. o UOl 8 u~ , ~ , u, ~ m o ' ~o~o~o~o ~ . ~o e ~ ~
~v ~ ~ee~
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O~ O ,~ ~o ~ m ~
12 ~25~33 Example 27 A sample of dry polyacrylamide (~00-~00 ~icron particle size) was dissolved directly in water by agitation to form a O.lS wt. ~ solution. Dissolution required mixing for 75 minutes. The solution viscosity was measured as 23.6 cps.
Two samples of polymer from the same batch were ground to 70 microns using a cryogenic process, and an ambient grinding process in an air classifying mill tACM) pulverizer sold by MikroPul, Inc., respectively.
Both ground samples were suspended in surfactant--containing hydrocarbon oil and converted in water, according to the procedure of Example 4. Both samples of polymer dissolved in less than 10 minutes. Aqueous polymer solutions (0.15 wt. ~ polymer) from the two grinds had viscosities of 24.2 cps (cryogenic grind) and 1~.2 cps (ambient temperature grind).
This Example demonstrates one advantage of comminution by cryogenic grinding over comminution by molecularly-destructive a~bient temperature grinding.
The foregoing detailed description is given for clearness of understanding, and no unnecessary limitations should be inferred therefrom, as variations within the scope of the invention will be obvious to those skilled in the art.
.
.
. .
- -.
,
Field of the Invention This invention relates to water~soluble polymers and, more particularly, to a method of rapidly dis-solving such polymers in water.
Description of the Prior Art The use of solutions of water-soluble polymers in thickening and flocculating applications is well known ~uch applications include the clarification of aqueous solutions in papermaking, and in treatment of sewage and industrial wastes. Such solutions of polymers are also useful as stabilizers for drilling muds, and in the secondary recovery of petroleum by waterflooding.
Although these polymers are most often available commercially as powders or as finely divided solids, they are most frequently utilized in aqueous solutions.
This necessitates that the solid polymer materia' be dissolved in water. Although the various polymers are more or less soluble in water, difficulty is often experienced in preparing aqueous polymer solutions because of their slow dissolution and because the solid polymer is not readily dispersible in water.
Furthermore, dispersion of solid polymers in water is hindered by their tendency to clump or remain as agglomerates on contact with water. Lumps of solid polymer immediately form by the encapsulation of undissolved solids in an outer coating of water-wet polymer which retards the penetration of additional 12~;i9~3 watcr into the a~glomeratc. Although many of these lumps arc eventually dissolved by continued agitation, it is frequently impractical to agitate the solution for a sufficiently long period to obtain complete dissolution.
The foregoing problems are described in U.S.
patents Re. 2~,474 (July 8, 1974) and Re. 28,576 ~October 21, 1975) issued to Anderson et al.
The above-identified Anderson et al reissue patents describe a method of rapidly dissolving water-soluble polymers in which a polymer is dispersed lnto a water-in-oil emulsion, which emulsion is then inverted in water to release the polymer into solution. The Anderscn et al disclosures require an oil-to-water ratio 15 between 5:1 and 1:10.
Accordins to the Anderson et al disclosures, emulsions containing between 5 and 75 weight percent polymer dispersed therein can be prepared and inverted into aqueous solution. However, it has been found in practice that the upper limit of the polymer content of an emulsion made according to the Anderson et al process is much lower than 75 weight percent, and usually is in the 10-35 weight percent range, depending upon the characteristics of the particular emulsion.
Further, the Anderson et al system, in practice, requires substantial amounts (e.g. 20 wt. ~, or more, based on oil) of an emulsifier in the oil/water/polymer emulsion to provide a.stable product.
125~3~33 SUMMARY OF THE INVENTION
-The invention seeks to overcome one or more of the problems described above.
The invention as broadly claimed in one aspect pertains to a method of rapidly dissolving a water soluble polymer or gum in water which comprises the steps of preparing finely-divided particles of the polymer or gum by comminuting the polymer or gum under substantially non-molecularly destructive conditions, dispersing the particles in a substantially water-free liquid carrier in which the polymer or gum is substantially insoluble to form a suspension, and adding the suspension to water with sufficient mixing to disperse and rapldly dissolve the particles in the water.
A preferred polymer is a polyacrylamide polymer, and the finely-divided particles of polyacrylamide are prepared by comminuting the polymer under cryogenic grinding conditions.
The suspension may be added to water in the presence of an emulsifier or a surfactant. Alternatively, an emul-sifier may be added to the liquid carrier before additionof the polymer or gum to the carrier~ The liquid carrier may be soluble or insoluble in water.
The polymer or gum particles are prepared by a comminution process which does not degrade the molecular structure of the polymer or gum. Only very low levels of emulsi~ier and/or surfactant, or none at all, are required to provide a stable product.
Other aspects and advantages will be apparent from the following detailed description.
DETAILED DESCRIPTION OF THE INVENTION
. _ . .
The Water Soluble Polymers These polymers are well known in the art and have been described in numerous publications and patents. They include, but are not limited to, naturally occurring galactomannan gums such as guar and locust bean gums, . l . .
~2S~3~3~
alginate salts, biologically produced polymers (e.g.
~anthan gum), polyethylene o~ides, water soluble condensation polymers, and vinyl addition polymers such as polyacrylamides and copolymeric derivatives of acryIamide with, for example, acrylic acid, m~leic anhydride, acrylonitrile, styrene, allyl or diallyl amines or dimethylaminoethylmethacrylate (D~EM). Such polymers may be nonionic, anionic or cationic.
The~-gums are well-known water-soluble polymers, and include those described in Volume lO of the En-cyclopedia of Chemical Technology, 2nd Edition, Interscience Publishers, 1966.
The molecular weight of the polymers described above may vary over a wide range, e.g. between about 10,000-25,000,000, and molecular weight is not a - critical parameter in this invention. The invention finds-~its greatest usefulness in preparing aqueous solutions or dispersions of these polymers and is particularly useful with respect to acrylamidé polymers, the molecular weights of which are in excess of 1 million.
` Polymers havin~ relatively high molecular weights previously were dissolved in water only with difficulty and tended to form extremely viscous solutions at relatively low concentrations. The polymers may be produced by any suitable me~hod of conducting polymerization reactions. Thus, solution, suspension or emulsion polymerization techniques may be used.
As used herein, the term "polymer" is`understood to include polymers and gums which are soluble in water to a significant degree. The polymers are solid, but may have a substantiàl water content. ~
. ~ ~
.
~ ~ ~9~3 The invention i5 capable of rapidly producing aqueous solutions of water soluble synthetic or natural polymers having polymer concentrations within the ranye of 0.1-10% by weight, with preferred concentrations within the range of 0.2-2.0~ by weight.
The Commlnution Process The rate of polymer dissolution in water is a function of surface aréa and, consequently, particle size. Polymers produced by most manufacturing processes are in the form of powders or lump-like agglomerates.
Largeiparticle sizes minimize handling and dusting problèms and reduce the formation of gel particles during dissolution in water. However, large prarticle size~increases dissolving time when dry particles are added dlrectly to water.
Therefore, it is desirabLe that the particles be comminuted by grinding, abrading or slicing so as develop the large surface area which promotes rapid dissolution when the polymer particles subsequently contact water. The preferred particle size of the polymer or gum is determined by the desired improvement in dissolùtion rate in water and will genera~lly be less than 100 microns and preferably less than 7~0 microns.
~ - Small particle size also promotes suspension stability.
Many of the polymers amenable to this process are subject to molecular degradation by heat generation during comminution. For such heat sensitive polymers, comminution without molecular degradation may be achieved through cryogenic grinding, such as by the use of carbon dioxide or liquid~nitrogen to reduce the temperature of the polymer prior to and/or during the grinding or sliclng process. Certain polymers that .
,, ' ' , - .
6 ~5~733 become plastic or sticky at temperatures developed in ambient temperature grinding processes can also benefit ~rom cryogenic grinding.
Such cryogenic processes employ pulverizing equipment such as that marketed by Pulverizin~ ~achinery Company of Summit, NJ under the trademark "~ikroPul".
Comminuting equipment that employs a slicing action, such as that sold by Urschel Laboratories of Valparaiso, IN under the trademark "Comitrol" may be additionally employed to further reduce particle size in the polymer suspension itself. The comminuting process and equipment are chosen to protect the polymer from significant molecular degradation and to produce the desired dissolution rate when the polymer suspension is introduced into water with mixing.
The Suspension From a commercial standpoint it is beneficial that the suspension of polymer be stable so that agitation of the stored suspension is minimal or not required, and that polymer concentration be`as high as possible to minimize~freight costs. Suspensions as high as about 70-75 wt.~ polymer solids may be produced according to this invention, depending on particle size, carrier viscosity and the effect of suspending or dispersing agents on suspension viscosity. The preferred range of polymer solids in the suspension is about 50g~-70gO by weight. Suspension stability is enhanced by relatively fine comminution of the polymer or gum and by a high viscosity li~uid carrier. Additionally the carrier may be treated with suitable thickening, dispersing, suspending or viscosity modifying agents such as those well known in the art.
..
. .
- . - , -. .
~2~73~
A particularly advanta~eous method of increasing stability with hydrocar~on oil carriers is to add an oil-in-~ater emulsifier such as the isooctylphenoxypo1yethoxyethanol product sold by ~ohm &
Haas under the trademark "Triton X-100." When this oil-in-water emulsi~ier is added to a hydroc~rbon carrier it performs the dual functio~s of increaslng suspension stabili~y and emulsifying the hydrocarbon in the water in which the polymer is ~o subsequently dissolve, thus speeding dissolution of the polymer by exposing oil-free polymer surfaces to the water.
The polymer must not be soluble in the liquid carrier, and the carrier should be substantially water-free. However, the liquid carrier may be either soluble or insoluble in water.
Since the liquid carrier is substantially water-~ree, a water-in-oil emulsion is not formed, in contrast to the process o Anderson et al reissue patents 28,474 and 28,576, identified above. Although the solid polymer may have a substantial water content, this water content does not result in the formation of a water-in-oil emulsion.
Suitable hydrocarbon oil carriers include, but are not limited to, parif~in-based oils such an Conoco's LOPS (low order para~f~n solvent) and Exxon's Faxam.
Exxon's Isopar M, a deodorized high purity isoparaffinic material, is also suita~le, as are the hydrocarbon liquids disclosed .in Anderson et al~ Re. 28,474 and 28,576.
Water-soluble or water-dispersible carriers in which the polymer is insoiuble under practical conditions may also be used in producing ~he polymer suspension. In the case wherein the liquid c~rrier is * trade mark ~2~ 3 water soluble, no surfactant is needed. ~xamples of such carriers include, but not limited to, higher alcohols, glycols and glycol ethers.
Dissolving The Polymer When a polymer-containing suspension of the type described herein is dispersed in water the polymer rapidly dissolves in the water. The polymer con-taining suspension will produce a water solution in a very short time when compared to the amount of time required to dissolve the conventional solid form of the polymer.
The polymer-containing suspension may be dispersed in water by any suitable means. Where a ~ater insoluble carrier is used, the most convenient means is to use a surfactant present in either the polymer containing suspension or the water in which the polymer is to be dissolved. The surfactant causes the carrier to rapidly emulsify in the water (forming an oil-in-water emulsion), thus expediting formation of the aqueous solution of the polymer. When this technique is used to invert the polymer-containing suspension to an aqueous solution the amount of surfactant present in the water may vary over a range of 0.01~ to 30% based on polymer. Good conversion often occurs within the range of 1.0~ to 8~ based on carrier.
The preferred surfactants for use with a polymer suspension in a hydrocarbon liquid carrier are hydrophilic and water soluble. Any anionic, cationic or nonionic hydrophilic compound can be used as the surfactant although it is~best to choose a surfactant whose ionic properties do not react with those of the polymer in solution.
. .
.
9 ~2~ 733 In addition to using water-soluble surfactants with hydrocarbon carriers, other surfactants such as silicones, clays and the like may be used since in certain instances they tend to emulsify a hydrocarbon carrier even though they are not themselves water-soluble.
By the use of this process different polymers may he com~ined into a single suspension so that when the polymers of the suspension are dissolved in water as a co-solution the technical performance of the mixture is enhanced. Such combinations include, but are not limited to, nonionic polyacrylamide with either anionic or cationic polyacrylamide copolymers, anionic poly-acrylamide copolymer with biopolysaccharide, poly-ethylene oxide with nonionic polyacrylamide, poly-ethylene oxide with cationic or anionic polycrylamide copolymers, or biopolysaccharide with galactomannan gums.
Examples Examples 1-26 To illustrate the invention, Examples 1-26 are summarized below in the Table. A variety of suspensions were prepared containing different water-soluble polymers and gums and using differing types of liquid carriers. The suspensions were then converted to polymer solutions in water using different conversion techniques and the time for polymer dissolution was compared to that for dissolution of the dry polymer or gum in its commercially available form. In all cases significant reductions in dissolving time were noted and the usual problems associated with handling and dis-persing dry polymer or gum were eliminated.
...
.
.
- . -.
-.
`` ~2597~:3 In those Examples in which the liquid carrier was ahydrocarbon oil, the hydrocarbon oil was a mixture comprising #2 diesel oil (50~) and Faxa~Z2 (S0~).
(Faxam~22 is a general purpose para~fin based oil marketed by Exxon.) In those Examples in which a surfactant was present, ~he sur~actant was Triton X-100 and was present in the suspension or water in an amount calcula~ed to give a nominal 2 wt % surfactant content, based on product. Where an emulsifier was used, the emulsifier was Triton X-100 , and was present in the suspension in an amount calculated to give an emulsifier concentration of about 2 wt %, based on suspension.
In Example 26, a small amount (about 1% by weight, based on suspension) Bentone SD-l ~a clay dispersant sold by NL Industries) was added to the suspension in order to enhance stability.
All percentages of carrier and polymer or gum are based on the total suspension. In each Example, sufficient suspensio~ was mixed with water to give an aqueous solution polymer concentration of about 0.2 wt %.
* trade mark ,. ~
` . . - . . .
Cl ~
~ ~ o o o o o o o o o ~ o o o o U~ ~. o U~ o o o U) o a~ A V V V V ,~ V ~V ~ V ~ V A V ~ V A V A V A V A V
. ` ' . ,, ' '.
~ ~ I --~ ~`0~ N N I N I ~1 I ~I t ~ `1 I t~l I ~1 1 N I t`J I N
,~ ,~ o ~~ 8,~ o ,~ u~ o u~ 8 ~ o u~ o ,~ o ~ o 1 l~i N '~ 8 o o v 8 v A V A V ~ V g V A V I V V
" .~
~ m m m m m ~1 m~! m ~ m ~ m ~ m .~
8 ~ o~o~o~
. ......... ,, . o o~
8 ~ ~ ~ ~ ~ o ", o ", o " o U~ o u. o UOl 8 u~ , ~ , u, ~ m o ' ~o~o~o~o ~ . ~o e ~ ~
~v ~ ~ee~
~ B
O~ O ,~ ~o ~ m ~
12 ~25~33 Example 27 A sample of dry polyacrylamide (~00-~00 ~icron particle size) was dissolved directly in water by agitation to form a O.lS wt. ~ solution. Dissolution required mixing for 75 minutes. The solution viscosity was measured as 23.6 cps.
Two samples of polymer from the same batch were ground to 70 microns using a cryogenic process, and an ambient grinding process in an air classifying mill tACM) pulverizer sold by MikroPul, Inc., respectively.
Both ground samples were suspended in surfactant--containing hydrocarbon oil and converted in water, according to the procedure of Example 4. Both samples of polymer dissolved in less than 10 minutes. Aqueous polymer solutions (0.15 wt. ~ polymer) from the two grinds had viscosities of 24.2 cps (cryogenic grind) and 1~.2 cps (ambient temperature grind).
This Example demonstrates one advantage of comminution by cryogenic grinding over comminution by molecularly-destructive a~bient temperature grinding.
The foregoing detailed description is given for clearness of understanding, and no unnecessary limitations should be inferred therefrom, as variations within the scope of the invention will be obvious to those skilled in the art.
.
.
. .
- -.
,
Claims (22)
1. A method of rapidly dissolving a water-soluble polymer or gum in water which comprises the steps of:
(a) preparing finely-divided particles of said polymer or gum by comminuting said polymer or gum under substantially non-molecularly destructive conditions;
(b) dispersing said particles in a substantially water-free liquid carrier in which said polymer or gum is substantially insoluble to form a suspension; and, (c) adding said suspension to water with sufficient mixing to disperse and rapidly dissolve said particles in said water.
(a) preparing finely-divided particles of said polymer or gum by comminuting said polymer or gum under substantially non-molecularly destructive conditions;
(b) dispersing said particles in a substantially water-free liquid carrier in which said polymer or gum is substantially insoluble to form a suspension; and, (c) adding said suspension to water with sufficient mixing to disperse and rapidly dissolve said particles in said water.
2. The method of claim 1 wherein the liquid carrier is a hydrocarbon oil and a hydrophilic emulsifier is present in the suspension or in the water in which the polymer or gum is to be dissolved, so as to form an oil-in-water emulsion in step 1(c) to promote rapid dissolution.
3. The method of claim 1 wherein said particles are insoluble in the liquid carrier, and said liquid carrier is soluble or easily dispersible in the water to which the suspension is added.
4. The method of claim 1 wherein said polymer or gum comprises between about 10% and about 70% by weight of said suspension.
5. The method of claim 1 wherein a suspending or dispersing agent is present in said liquid carrier.
6. The method of claim 1 wherein said polymer or gum comprises a blend of one or more polymer(s) and gum(s).
7. The method of claim 1 wherein the size of said particles is less than about 70 microns.
8. The method of claim 1 wherein said comminution step is carried out by means of cryogenic grinding.
9. The method of claim 1 wherein said particles are substantially insoluble in said liquid carrier and said liquid carrier is soluble in water.
10. The method of claim 9 wherein said polymer or gum comprises between about 10% and about 70% by weight of said suspension. ,
11. The method of claim 9 wherein said polymer or gum comprises a blend of one or more polymer(s) and gum(s).
12. The method of claim 9 wherein the size of said particles is less than about 70 microns.
13. The method of claim 9 wherein said comminution step is carried out by means of cryogenic grinding.
14. A method of rapidly dissolving a polyacrylamide polymer in water which comprises the steps of:
(a) preparing finely-divided particles of said polyacrylamide polymer by comminuting said polymer under cryogenic grinding conditions;
(b) dispersing said particles in a substantially water-free liquid carrier in which said polymer is substantially insoluble to form a suspension;
and, (c) adding said suspension to water with sufficient mixing to disperse and rapidly dissolve said particles in said water.
(a) preparing finely-divided particles of said polyacrylamide polymer by comminuting said polymer under cryogenic grinding conditions;
(b) dispersing said particles in a substantially water-free liquid carrier in which said polymer is substantially insoluble to form a suspension;
and, (c) adding said suspension to water with sufficient mixing to disperse and rapidly dissolve said particles in said water.
15. The method of claim 14 wherein the liquid carrier is a hydrocarbon oil and a hydrophilic emulsifier is present in the suspension or in the water in which said polymer is to be dissolved, so as to form an oil-in-water emulsion in step 1(c) to promote rapid dissolution.
16. The method of claim 14 wherein said particles are insoluble in the liquid carrier, and said liquid carrier is soluble or easily dispersible in the water to which the suspension is added.
17. The method of claim 14 wherein said polymer comprises between about 10% and about 70% by weight of said suspension.
18. The method of claim 14 wherein a suspending or dispersing agent is present in said liquid carrier.
19. The method of claim 14 wherein the size of said particles is less than about 70 microns.
20. The method of claim 14 wherein said polymer is substantially insoluble in said liquid carrier and said liquid carrier is soluble in water.
21. The method of claim 20 wherein said polymer comprises between about 10% and 70% by weight of said suspension.
22. The method of claim 20 wherein the size of said particles is less than about 70 microns.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000467149A CA1259733A (en) | 1984-11-06 | 1984-11-06 | Method of rapidly dissolving polymers in water |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000467149A CA1259733A (en) | 1984-11-06 | 1984-11-06 | Method of rapidly dissolving polymers in water |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1259733A true CA1259733A (en) | 1989-09-19 |
Family
ID=4129087
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000467149A Expired CA1259733A (en) | 1984-11-06 | 1984-11-06 | Method of rapidly dissolving polymers in water |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1259733A (en) |
-
1984
- 1984-11-06 CA CA000467149A patent/CA1259733A/en not_active Expired
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