DE1945340A1 - Process for the preparation of graft copolymers of acrylic acid with polymeric polyhadroxy compounds, and graft copolymers of the same - Google Patents

Description

J 537

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International Minerals & Chemical Corporation, Skokie, Illinois, V.St.A.

Process for the preparation of graft copolymers of Acrylic acid with polymeric polyhydroxy compounds, and Graft copolymers of the same

The invention proposes water-soluble graft copolymers of acrylic acid and polymeric polyhydroxy compounds and water-soluble ones Salts of these graft copolymers, it being possible for the polyhydroxy compounds to be:

(a) derivatives of cellulose, such as chlorohydroxypropyl cellulose, phenylhydroxyethyl cellulose, hydroxybutyl cellulose, hydroxyethyl cellulose, Ethyl cellulose, hydroxyethyl methyl cellulose, Hydroxypropylmethyl cellulose and carboxymethyl cellulose,

(b) strength,

(c) derivatives of starch, such as chlorohydroxypropyl starch, phenylhydroxyethyl starch, hydroxybutyl starch, hydroxyethyl starch, Methyl starch, ethyl starch, hydroxyethylmethyl starch, hydroxypropylmethyl starch and carboxymethyl starch,

(d) sugar,

(e) etched lighite,

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(f) biochemically synthesized heteropolysaccharides,

(g) polyvinyl alcohol,

(h) polyalkylene glycols, and
(i) alkoxy-polyalkylene glycols.

The so-called "grafted" polymers are well known in the art. There are several methods of manufacture these grafted polymers have been proposed. These procedures require either side chain bil- ™ Ending monomers in the presence of other, already preformed polymers stimulates the polymerization, which acts as the main chain serve and to which the polymerizing monomers are bound, or side chain macromolecules with another Linked macromolecule that is produced separately and serves as the main chain. The graft copolymers produced in this way differ from other polymers because of their special properties.

It is well known in the art to use graft polymerizations *? Using techniques to determine properties of various materials such as cellulose and cellulosic materials fc to modify. For example, in U.S. Patent No. 2,922,768 to Mino and Kaizerman, one method of manufacture is disclosed described by graft copolymers in which a polymerizable vinyl monomer such as acrylic acid or methacrylic acid in an aqueous medium at a pH of not more than 3.5 and a polymeric organic reducing agent such as cellulose or polymerized methyl cellulose in the presence of a cerium salt will. Paessinger and Conte in U.S. Patent 3,359,234 suggest a method for making Graft copolymers, which is characterized in that a water-insoluble cellulose or a starch bound (amylaceous) monothie carbonate or di thiocarbonate -Substrate with acrylic acid or another ethylenically unsaturated Monomers through free radical initiation Can react peroxide.

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The polymers can advantageously be used to refine clays by chemical treatment, in particular for them for use in bonr sludge when drilling wells to make useful with widely varying composition. This is detailed in the parallel running, application filed at the same time as this application (file number J 538) and described claimed.

There are two general types of clays suitable for drilling in liquid media or muds: the western or natural sodium bentonite clays and the native or sub-bentonite clays. The yield value of a particular tone is the determining factor Paktor if its use is being considered in the preparation of a drilling mud.

The water-soluble graft copolymers of the present Invention can be prepared by graft copolymerizing acrylic acid on a smaller amount of a substrate that is, the water-soluble polymeric polyhydroxyl halide as defined above Connection represents.

The graft copolymers of this invention are prepared by reacting acrylic acid with about 0.1 to 10 wt .- i? _F based on the weight of acrylic acid, a water-soluble polymeric polyhydroxy Verbinjiung in an aqueous medium at a pH of no more than about 3.5 allowed to react to initiate the reaction with ultraviolet light or a peroxide type polymerization catalyst. The graft copolymers prepared in this way can be converted into the salt form by adding a suitable alkali metal hydroxide such as sodium hydroxide to an aqueous medium containing the polymer in an amount sufficient to neutralize the polymer. Optionally, the aqueous medium containing the polymer in either the acid form or the salt form is heated according to conventional techniques to obtain a dry water-soluble polymer.

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The substrates which are reacted with the acrylic acid in order to produce the useful graft copolymers are water-soluble polymeric polyhydroxyl-containing compounds. In general, these polymeric compounds can be characterized as having a molecular weight greater than about 350 and ^{containing at least 5%} free hydroxyl groups. The polymeric compounds can be up zu.30 ° / o and even contain more free hydroxyl groups. It is clear that the polymeric polyhydroxyl compounds can also contain other substituents than the hydroxyl groups, provided the substituents are inert, ie they do not react with the acrylic acid under the reaction conditions. Examples of substituents other than the mere hydroxyl groups which the polymeric compounds may contain are halogen, alkyl, aryl, carboxyalkyl, hydroxyalkyl, halohydroxyalkyl, aryihydroxyalkyl and the like.

Useful polymeric substrates include water-soluble polysaccharides and polyhydroxyl-containing derivatives thereof. Even though Disaccharides and trisaccharides which can be used in the present invention are the preferred polymeric compounds Tetra, penta and higher polysaccharides and oligosaccharides, i.e. saccharides, the at least four linked monosaccharide molecules and derivatives thereof which contain the above-mentioned Dubstituenten. Among the most preferred Substrates include derivatives of cellulose and biochemically synthesized heteropolysaccharides.

Some of the specific polymeric polyhydroxy compounds that which can be used as substrates in preparing the novel copolymers of this invention are water soluble Derivatives of cellulose such as chlorohydroxypropyl cellulose, phenylhydroxyethyl cellulose, kydroxybutyl cellulose, hydroxyethyl cellulose, Ethyl cellulose, hydroxyethyl methyl cellulose, Hydroxypropylmethyl cellulose, carboxymethyl cellulose and similar cellulose ethers, however, the selection is not limited to these. Other polymer compounds, which with acrylic acid

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BATH ORIGINAL

re can be reacted according to the invention are starch and water-soluble derivatives of starch, e.g. chlorohydroxypropyl starch, phenylhydroxyethyl starch, hydroxybutyl starch, methyl starch, ethyl starch, hydroxyethyl starch, hydroxyethyl methyl starch, hydroxypropyl methyl starch and carboxymethyl starch. Other polymeric materials that can be used are the so-called "sugars" such as sucrose, maltose, lactose, raffinose, stachyose and vertascosej etched lignite; biochemically synthesized heteropolysaccharides, for example those which are produced by the action of bacteria of the genus Xanthomonas or the genus Arthrobacter on carbohydrates; Polyvinyl alcohol and polyalkylene glycols and derivatives thereof such as alkoxypolyalkylene glycols, for example polyethylene glycols and methoxypolyethylene glycols. It will be apparent to those skilled in the art that useful compounds include those compounds which form the polymeric compounds defined above in the acidic reaction medium, and such compounds are within the scope of the present invention. For example, carboxymethyl cellulose is formed from the sodium salt thereof in the acidic reaction medium.

The amount of the substrate which reacts according to the invention with acrylic acid can be between about 0.1 and 10.0% by weight, preferably between about 0.25 and 5% by weight , based on the total weight of the acrylic acid used, vary.

The graft copolymerization of this invention can be carried out using the well-known polymerization techniques are carried out. Ultraviolet light or any of the general known peroxide initiators, e.g., free radical peroxide initiators, can be used in the process of this invention will. The preferred peroxide initiators are hydrogen peroxide and hydroperoxides such as tert-butyl hydroperoxide, diisopropylbenzene hydroperoxide, Cumene hydroperoxide, 1-phenylethyl hydroperoxide and similar. Other peroxide initiators that can be used are diacyl peroxides such as benzoyl peroxide and acetyl peroxide

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oxide and diacyl peroxides such as di-tert-butyl peroxide and dicumyl peroxide. Other useful peroxide initiators include the per-salts such as sodium, potassium or ammonium persulfate and sodium perborate; the per-esters such as tert-butyl peroxyacetate and. tert-butyl peroxybenzoate and the peracids such as performic acid, Peracetic acid, perbenzoic acid and peroxymlactic acid. If necessary, Eedox-activated systems can be used according to normal polymerization practices can be used. So can sodium bisulfite-potassium persulfate and hydrogen peroxide-iron ion systems be used. However, when using a redox-activated system, it may be necessary to for the best results add the peroxide initiator in proportions to avoid competitive chain termination reactions, i.e. to keep combination and disproportionation to a minimum.

The amount of initiator used can be varied, depending on the reaction temperature and other conditions * but it will usually be from about 0.005 to 0.1%, preferably from about 0.002 to 0.004% , based on the weight of the acrylic acid.

In carrying out the method, the erfindungsgeißäSen ψ reaction temperature is not critical and may vary between about -5 ° C and 100 ⁰ C. Of the. preferred. Liögt temperature range between about 40 C and 80 C, with a temperature between about 60 ⁰ C and 70 ⁰ C is most preferred. The reaction can be carried out under overpressure or even under partial vacuum. However, it is preferred to use atmospheric pressure for convenience because the reaction proceeds very favorably at this pressure. Optionally, the reaction can be carried out under an inert atmosphere such as nitrogen or helium.

The graft copolymerization reaction of this invention is carried out in an acidic aqueous medium. The pH value of the Reaction medium can be any value up to and including about 3.5.

009811/1636 ßADOfUGINAL

It is preferred to keep the pH between about 3.0 and 3.5 for optimal results. In the event that the amount of acrylic acid used is not sufficient to lower the pH of the reaction medium to a Vert of 3.5 or lower, the desired pH can be achieved by adding a suitable mineral acid such as sulfuric acid, nitric acid or hydrochloric acid can be obtained.

The reactants and initiators are brought together in the aqueous reaction medium in a royal royal chamber. However, the initiator should not be added to a reaction medium that contains only the acrylic acid, as this could lead to the polymerization of the acrylic acid in the absence of the polymeric polyhydroxy substrate. An example of a suitable way of combining the reaction partners is to dissolve the acrylic acid and the polymeric compound in separate amounts of water, so that homogeneous solutions of the same are created. These solutions are mixed, and the initiator is then added z. ~ I of the mixed solution. Alternatively, the polymeric substrate material can be dissolved in water to create an isogenic solution to which the acrylic acid and initiator are added. Other methods of combining the heating part and the initiator are known to those skilled in the art. The best results are obtained when the polymeric substrate is carefully dissolved in at least part of the aqueous reaction medium before it is combined with the acrylic acid. Cooling or shaking the reaction mixture facilitates the polymerization and leads to more uniform polymers.

The reaction time varies depending on the reaction temperature and / or the amount of initiator present. In general, the time should be sufficient to consume at least 95 P of the acrylic acid. In order to illustrate the variation of the reaction time at different temperatures, it should be noted that the polymerization was carried out in about 5 to 7 hours when the acrylic acid at 60 ⁰ C with about 1.0 wt .- ^ carboxymethyl cellu- '

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BUILDING

loosely, based on the weight of the acrylic acid, and 0.002 wt .- $ hydrogen peroxide, based on the weight of the acrylic acid, reacted. On the other hand, the polymerization was complete in about 15 to 20 minutes if the reaction was carried out at 100 ^° C. using the same proportions of the reactants and the initiator. The polymerization can be followed by the change in the refractive index, and the end of the reaction can be determined by the absence of the characteristic odor of acrylic acid.

After the polymerization reaction has ended, the thus prepared Copolymer can be converted into the salt form. This transfer is generally done by neutralizing with a suitable hydroxide. Alkali or ammonium salts of the copolymers, such as the sodium, potassium and lithium salts, can be obtained by allowing the copolymers to react with the corresponding hydroxide. Where complete neutralization is desired, a stoichiometric amount and preferably a small excess of the hydroxide is used. Partial salts can of course by using less than the amount of alkali or ammonium hydroxide required for complete conversion of the carboxyl groups.

The copolymers of this invention, either the acid form or the salt form, can be converted to a dry form if desired. This can be done using conventional techniques such as by heating the aqueous solution of the copolymer in a drying drum at a temperature of about 105.degree can be achieved to drive off the water and obtain a dry polymer.

The graft copolymers produced in this way are either in the Acid form or the salt form used to treat bentonite and sub-bentonite clays to make them particularly useful in drilling muds. When the graft copoly-

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merisate of this invention used for clay treatment, the copolymer is combined with the clay in a desired manner. For example, a simple mechanical Mixing of the clay and the copolymer by dry blending of the copolymer in powder form directly with the dry one Tone achieved. Conveniently, this can be done in the time when the clay is being ground, such as in a Roller mill. On the other hand, an aqueous solution of the copolymer can be applied directly to the clay either in storage heaps, after breaking, during a grinding process or during packaging in sacks, «The clay and that Copolymers can optionally also be added separately in a desired order to form a slurry to build. This type of wet mixing could be used on the manhole side, for example.

The clay is treated with a sufficient amount of copolymer to increase the yield of the clay. The one needed Amount of the copolymer depends in a certain Dimensions depend on the level of finishing desired and vary with the clay, but generally only small amounts are required. Quantities ranging from about 0.1 to 20 0.4536 kg each 1.016 tons of clay give satisfactory results. The preferred amounts for treatment are from about 1 to 15 x 0.4536 kg polymer per 1.016 tons of clay.

If the clay to be treated is a sub-bentonite or calcium montmorillonite clay, the graft copolymers are This invention is used with the best results together with an alkali compound that is water-soluble, ionizable and has an ion that can react with calcium to form a water-insoluble precipitate. To such Compounds include, for example, alkali carbonates, hypophosphates, oxalates, phosphates, silicates, sulfites and tartrates. Sodium carbonate or soda ash are particularly preferred. The amount of alkali used will depend roughly on the proportion of calcium inontmorillonite in the total clay. in the

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5 3 40

-io-

in general , amounts of about 0.5 to 7 % by weight of clay can be used, with increasing amounts resulting in a higher degree of refinement. However, it is preferred to use amounts of slightly less than 7 ° , since amounts in excess of this amount can act to reduce the clay yield. Soda ash with the preferred amounts are for example about 2 to 4 wt. ~ 4>, wherein the best results are obtained with about 3 wt .-%.

It will be clear to those skilled in the art who are familiar with this field shine that the drilling muds, which contain the copolymers in combination with clay, also have additional materials which may contain clay, polymer and water. For example, the drilling mud can also contain weighting agents such as barite, oil, treatment chemicals such as caustic sodium, surface-active agents Contain agents and other materials commonly found in or added to drilling muds will.

The following non-limiting examples become the present Explain the invention further.

* Example I.

According to the invention, graft copolymers were produced in experiments using several different types of water-soluble polymeric polyhydroxy materials as substrates. The polymeric materials used in these experiments were carboxymethyl cellulose, a heteropolysaccharide made by the action of Xanthomonas campestris on carbohydrates and sold under the name XC-Polymer, another bacteriologically made polymer available from General Mills Corporation under the name XB-23 is to be obtained, etched lignite _? Sucrose, starch and polyvinyl alcohol.

In each experiment a solution of 0.1 g of the corresponding -: dan polymeric material in 84 ml of distilled water in a

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made in a glass bottle. It then became crystallizable Ice acrylic acid in an amount of 9 »9 g (9.35 ml) and finally Add 0.1 ml of a 30% hydrogen peroxide solution to the Solution was added while it was stirred. The reaction vessels were purged with nitrogen, sealed, and then 24 Held at 40 ° C. for hours with intermittent stirring to allow the polymerization to take place. The copolymerization products were finally treated in each of the vessels with 8 ml of a 50% aqueous sodium hydroxide solution to remove the To convert polymers into the sodium salt form.

Another set of tests was conducted to determine the effectiveness of the polymers prepared as explained in Example I in the larger -usable utilization of clays for mud drilling to demonstrate, that is, to increase the yield of clays. A clay-water slurry was used in these experiments with a solids content of 4.536 kg per ton produced by deionizing a Western bentonite and distilled water was added. The slurry was covered and allowed to stand for a period of about 24 hours. After this resting period of aging, various amounts of a 10% solution of one as in Example I were prepared Polymer is added to various samples of the slurry, the treatment degrees with 3 to 15 times Imagine 0.4536 kg per 1.016 tons. The slurries were mixed. Immediately after mixing, the viscosities of each slurry were measured with a Fann viscometer 600 rpm determined and recorded. The results of these tests demonstrated the effectiveness of the graft copolymers of this invention for treating clays are shown in Table I. The results of these tests clearly show a person skilled in the art that the copolymers of this invention are effective in treating clays to produce a clay of increased yield to obtain.

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grafted

Polyhydroxy

Substrate

Carboxymethyl cellulose

XC polymer

XB-23

etched sucrose starch P ο Iy vinyl aiko Jaol

-12-

Table I

Amount of Viscosity, Polymer, 600 rpm, 0.4536 kg / 1.016 t 3? Ann reading - 5 3 41 6th 68 9 77 12th 80 * 15 71 3 47 6th 69 9 73 12th 68 15th 55 3 48 6th 70 9 78 12th 74 15th 61 3 49 6th 52 9, 33 3 44 6 '. ■ ' 59 9 54 3 46 6th 59 9 50 3 50 6th 60 9 44 Example II

In another experiment, on a larger scale than in
Example I was carried out, were 50 χ 0.4536 kg of water
of 15.5 C and 14 g of carboxymethyl cellulose are placed in a clean, open 68-liter stainless steel kettle with a variable-speed stirrer.

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BATH ORIGINAL

rer, thermometer, temperature control and heating mantle. After the Garboxymethylcellulose was thoroughly dissolved, the temperature of the solution was raised to 68.5 ° C, and acrylic acid were ice-χ 60 0.4536 kg pure and 272 g of a 30 followed by hydrogen peroxide solution was added. The reaction mixture was then held for about 5 hours between about 65.5 ° C and 83.5 ⁰ O until the polymerization reaction was complete.

The graft copolymer prepared in this way was with regard to the treatment of western bentonite, essentially as set forth in Example II and found useful in increasing the yield of the clay. Similar Results were again obtained when the co-polymer as a clay treating agent after neutralizing with sodium hydroxide.

Although this invention is in terms of specific embodiments has been described, it is understood that changes can be made by one skilled in the art without thereby departing from the intended aim of the invention as defined by the following claims.

Patent claims:

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Claims (25)

• 14- J 537 patent claims: 1. Water-soluble graft copolymer of acrylic acid and polymer Polyhydroxy compound or water-soluble salts thereof, where the polymeric compound can be: (a) derivatives of cellulose such as chlorohydroxypropyl cellulose, Phenylhydroxyethyl cellulose, hydroxybutyl cellulose, Hydroxyethyl cellulose, ethyl cellulose, hydroxyethyl methyl cellulose, Hydroxypropyl methyl cellulose and carboxymethyl cellulose, (b) strength, (c) derivatives of starch, such as chlorohydroxypropyl starch, Phenylhydroxyethyl starch, hydroxybutyl starch, hydroxyethyl starch, Methyl starch, ethyl starch, hydroxyethylmethyl starch, hydroxypropylmethyl starch and carboxymethyl starch, (d) sugar, (e) etched lignite, (f) biochemically synthesized heteropolysaccharides, (g) polyvinyl alcohol, (H). Polyalkylene glycols, and
(i) alkoxy polyalkylene glycols. 2. Copolymer according to claim 1, wherein the graft copolymer, the copolymerization product of from 0.1 to 10 parts by weight fi 7 the polymeric compound, based on the weight of acrylic acid, f. 3. Graft copolymer according to claim 1 or 2, wherein the, graft copolymerization product is the product of an excited by ultraviolet light or a peroxide compound graft copolymerization. 4. graft copolymer according to claim 3, wherein the graft copolymerization product the product of a hydrogen per-. · oxide or hydroperoxide induced graft copolymerization is. 009811/1836 19A5340 5. Graft polymer according to any one of claims 1-4, wherein the polymeric compound is present in an amount of about 0.25 to 5 weight percent based on the weight of the acrylic acid. 6. Graft copolymer according to any one of claims 1-5, wherein the polymeric compound is a polysaccharide containing at least four crosslinked monosaccharide molecules. 7. Graft copolymer according to any one of claims 1-5 »wherein the polymeric compound is carboxymethyl cellulose. 8. Graft copolymer according to any one of claims 1-5 »wherein the polymeric compound is starch or a derivative thereof. · 9 · Graft copolymer according to any one of claims 1-5, wherein the polymeric compound is a biochemically synthesized heteropolysaccharide. 10. Graft copolymer according to any one of claims 1-9, wherein this is the sodium salt. 11. Process for the preparation of graft copolymers, thereby characterized in that in an aqueous medium at a pH of not more than 3 »5, acrylic acid with about 0.1 to 10 wt .- # based on the weight of this acrylic acid, one water-soluble polymeric polyhydroxy compound copolymerized, whereby the reaction with ultraviolet light or a water-soluble peroxide compound is initiated, wherein the polymeric compound can be: (A) derivatives of cellulose such as chlorohydroxypropylcellulose, phenylhydroxyäthylcellulo se, hydroxybutylc ellulos e, Hydroxyethyl cellulose, ethyl cellulose, hydroxyethyl methyl cellulose, Hydroxypropylmethyl cellulose and carboxymethyl cellulose, (b) strength, 0 0 9 811/16 3 6 (c) starch derivatives such as chlorohydroxypropyl starch, phenylhydroxyethyl starch, Hydroxybutyl starch, hydroxyethyl starch, .Methyl starch, ethyl starch, hydroxyethyl methyl starch, Hydroxypropylmethyl starch and carboxymethyl starch, (d) sugar, (e) etched lignite, (f) biochemically synthesized heteropolysaccharides, (g) polyvinyl alcohol, (h) polyalkylene glycols, and
(i) alkoxy polyalkylene glycols. 12. The method of claim 11, wherein the reaction is initiated by a peroxide type initiator. 13. The method of claim 11 or 12, wherein the reaction initiated by a free radical peroxide initiator. 14. The method of claim 13, wherein the initiator in an amount of about 0.0005 to 0.01 wt .- ^ 6, based on the Weight of acrylic acid, is present. 15. The method according to any one of claims 11 to 14, wherein the Acrylic acid and the polymeric polyhydroxy compound at a temperature
to be brought. a temperature of about -5 ⁰ C to 100 ⁰ C for the reaction 16. The method of claim 15, wherein the reaction is initiated by hydrogen peroxide or a hydroperoxide. 17. The method according to claim 16, wherein the acrylic acid and the polymeric polyhydroxy compound are reacted ^{at a temperature of about 40 °} C. to 80 ^{° C.} 18. The method of claim 17, wherein the acrylic acid with about 0 * 25 to 5 wt .- $, based on the weight of the acrylic acid, the polymeric polyhydroxy compound is reacted. 90 ** 11/1636 1 η / _: -? 4 ο 19 · The method according to claim 18, wherein the initiator in an amount of about 0.002 to 0.004% by weight, based on the Weight of acrylic acid, is present. 20. The method of claim 16, wherein the polymeric polyhydroxy compound is a polysaccharide containing at least four linked monosaccharide molecules. 21. The method of claim 16, wherein the polymeric polyhydroxy compound is a derivative of cellulose. 22. The method of claim 21, wherein the polymeric polyhydroxy compound Is carboxymethyl cellulose. 23. The method of claim 16, wherein the polymeric polyhydroxy compound Is starch or a derivative thereof. 24. The method of claim 16, wherein the polymeric polyhydroxy compound is a biochemically synthesized heteropolysaccharide. 25. The method according to claim 16, wherein the graft copolymer of acrylic acid and the polymeric polyhydroxy compound in the salt form by reaction with ammonium or a Alkali hydroxide is transferred. J 537
Dr.Pa/Wr 009811/1636 ORIGINAL