US 3751411 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
United States Patent 3,751,411 COMPOSITIONS COMPRISING STARCHES CON- TAINING NONIONIC, BASIC AND ACIDIC GROUPS AND PREPARATION THEREOF Lee H. Elizer, Keokuk, Iowa, assignor to The Hubinger Company, Keokuk, Iowa No Drawing. Application July 28, 1970, Sen No. 58,988, which is a continuation-in-part of application Ser. No. 733,233, May 31, 1968, now abandoned. Divided and this application Feb. 18, 1972, Ser. No. 227,671
Int. Cl. C08b 19/013 US. Cl. 260-233.3 R '14 Claims ABSTRACT OF THE DISCLOSURE Compositions comprising starches, especially high amylose starches, containing nonionic, basic (cationic) and acidic (anionic) groups, preferably hydroxyalkylether (nonionic), tertiary amino, cyanamide or quaternary amino (cationic) and sulfonic acid or sulfonate groups or carboxylic or carboxylate, or phosphate or phos phonate (anionic), in the starch molecule, are prepared which are especially useful for sizing threads or yarns of mixed fibers such as, for example, cotton fibers and polyester fibers, viz, polyethylene terephthalate fibers, and hydrophobic fibers that are diflicult to size.
RELATED APPLICATIONS This application is a division of United States application Ser. No. 58,988 filed July 28, 1970, now US. Pat. 3,673,171 which is a continuation-in-part of United States application Ser. No. 733,233 filed May 31, 1968, now abandoned.
BACKGROUND OF THE INVENTION Starches in general are composed of two different types of polysaccharides, amylose and amylopectin. Both are composed of D-glycopyranose residues. Amylose is a linear molecule, whereas amylopectin has a branch chain molecular structure.
Formation of smooth gels of high amylose content starches, i.e., containing about 50% or more amylose, requires autoclaving under pressure. The inconvenience and costs occasioned thereby often makes the use of such starches economically unfeasible. Furthermore, the starch pastes, after gelatinization under pressure, tend to be unstable because of the tendency of the high amylose starch to separate from the water of gelation.
It is well known that starches are useful in sizing cotton fibers and for a wide variety of other industrial purposes. In recent years, many synthetic fibers have become available, and it has been difficult to find relatively inexpensive sizing compositions which are suitable for sizing a wide variety of these fibers, including mixtures of cotton and synthetic fibers. In particular, it has been difficult to provide suitable low cost sizing compositions for mixtures of polyester fibers and cotton. In common practice, the fibers are sized in the form of threads or yarns prior to weaving. The sized threads or yarns are then woven into cloth and thereafter the sizing material is removed by washing with water containing detergent or by treatment with enzymes. A satisfactory sizing composition is one which will provide suitable lubrication and resistance during weaving and at the same time can be readily removed thereafter.
One of the objects of the present invention is to provide new and improved starch products which are especially useful in textile sizing and can be employed for a wide variety of other purposes.
3,751,411 Patented Aug. 7, 1973 ice The present invention is concerned with the modification of starches and especially high amylose starches by chemically combining said starches through oxygen atoms of the polysaccharide molecules with hydroxyalkyl groups or hydroxyalkylether groups, basic and acidic groups. The added groups or substituents provide a starch composition containing non-ionic, anionic and cationic groups. These new and improved starch products are prepared by reacting an ungelatinized starch, preferably a high amylose starch containing about 50% or more amylose, with an alkylene oxide (e.g., ethylene oxide, 1,2-propylene oxide and/ or 1,2-butylene oxide), a nitrogen containing etherifying agent and also with a sultone. The preferred alkylene oxide is ethylene oxide, or 1,2-propylene oxide, or mixtures of ethylene oxide and 1,2-propylene oxide, or 1,2-propylene oxide followed by ethylene oxide. The preferred nitrogen containing etherifying agent is a dialkylchloroalkyl tertiary amine in the form of its hydrochloride salt such as 2-chloroethyldiethylamine hydrochloride, and the preferred sultone is propane sultone or butane sultone.
Ethylene oxide has the formula:
The 1,2-proylene oxide has the formula:
(II) CHrCH-CH O The 2-chloroethyldiethylamine hydrochloride (also called 2-chloro-N,N-diethylethylamine hydrochloride) has the formula:
A preferred procedure is to react the alkylene oxide with the ungelatinized starch, then add the nitrogen containing etherifying agent and the sultone, either sequentially or simultaneously. Thus, ethylene oxide can be added first, followed by the 2-chloroethyldiethylamine hydrochloride, followed by the addition of the propane sultone, or the alkylene oxide can 'be added to the starch followed by the propane sultone, followed by the addition of the Z-chloroethyldiethylamine hydrochloride, or the 2-chloroethyldiethylamine hydrochloride and the propane sultone can be mixed together in water to form a clear solution before stirring the mixture with a starch slurry after the starch has been pre-reacted with the alkylene oxide.
The basic amino groups are preferably introduced into the starch molecule by using as one of the reactants a tertiary amine or tertiary amine salt containing a reactive group linked to a hydrocarbon group of the amine.
The hydrocarbon group or groups of the amine can be alkyl (e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl), aryl (e.g., phenyl, tolyl), aralkyl (e.g., benzyl), or cycloaliphatic (e.g., cyclopentyl, cyclohexyl, or cycloheptyl). The amine can be a monoamine or a polyamine but is preferably a monoamine. It can also be a heterocyclic amine (e.g., piperidine, pyridine). Instead of a tertiary amine or amine salt, a quaternary amine or amine salt can be used. The cationic groups can also be introduced into the molecule by using cyanamide as a reactant. In general, however, from the standpoint of ease of carrying out the reaction and of desirable properties in the resultant products, it is preferred to use a water soluble amine or amine salt. The reactive groups of the amine are preferably either halogen (e.g., chloro-, bromo-, etc.) or epoxy. The portion of the amine to which the reactive group is attached is acyclic.
If a tertiary amine is used, the resultant products may be described by the following structural formula:
where X is starch, R is alkylene, preferably having 2 to 6 carbon atoms and more specifically 2 or 3 carbon atoms, R and R are hydrocarbon, preferably alkyl having 1 to 6 carbon atoms and more specifically 1 to 4 carbon atoms, R is alkylene which can be hydrocarbon substituted, preferably having 3 or 4 carbon atoms, Y is hydrogen or a salt forming radical, e.g., sodium, potassium, calcium, ammonium, x is 2 to 4, and n, m and p are numerical values representing the number of times the basic (cationic), acidic (anionic) and oxyalkylene radicals respec tively occur in the molecule.
While the values of n, m' and p may vary rather widely, the most useful range is 4% to 10% by weight of oxyalkylene groups, 0.5% to 6% by weight basic substituents and 0.5% to 6% by weight acidic substituents, based on the dry weight of the starch.
In general, the products can be given the formula where A11 is an anionic group, preferably sulfonic or sulfonate, but also carboxylic, carboxylate, phosphate or phosphonate; Cat is a cationic group, preferably tertiary amino, tertiary amine salt, quaternary amino or quaternary amine salt but also cyanamide; X is starch, R and R are alkylene, preferably having 2 to 6 carbon atoms; x is 2 to 4; m and n are each 0.5 to 6 per 100 anhydroglucose units in X; and p is 10 to 36 per 100 anhydroglucose units in X. The ratio of mm is usually Within the range of 3:1 to 1:3.
The formula does not necessarily depict the complete arrangement of groups within the molecule because the oxyalkylene groups could be linked between the starch molecule and the anionic and/or cationic groups or the anionic and/or cationic groups could be linked betweenthe starch molecule and the hydroxyalkyl groups, or the product couldbe in the form of mixtures of one or more such structures.
The starch molecule is usually considered to consist of a number of anhydroglucose units (AGU) each having a molecular weight of 162.14. Each AGU has three reactive hydroxyls but one of these reacts more readily than the others.
The term high amylose starch When used herein refers to any starch or starch fraction containing at least about 50% by weight amylose. Exemplary thereof are Nepol amylose (the amylose fraction of corn starch); Superlose (the amylose fraction of potato starch); A-mylomaize or Amylon (high amylosic corn starch with about 54% amylose); and Amylomaize VII (high amylose corn starch containing about 73.3% amylose). Amylomaize VIII with an amylose content of around can also be used. The starch can be of any origin, for example, corn, wheat, potato, waxy corn, tapioca, sago or rice.
While the invention is especially useful when the starch is high amylose starch, it is also useful when the starch is any one of the above enumerated starches other than a high amylose starch, including, but without limitation, regular thin boiling corn starch.
Sultones are intramolecular cyclic esters of hydroxysulfonic acids and may be derived both from aliphatic and from aromatic sulfonic acids. Examples of sultones suitable for the present purpose are 1,3-propanesultone, 1,4-butanesultone, mixtures of isomeric butanesultones (which may be prepared from mixtures of chlorobutanesulfonic acids, obtained by sulfochlorination of l-chlorobutane), benzylsultone and tolylsultone.
Where it is desired to introduce a carboxylic or carboxylate group, sodium chloroacetate or a higher homologue containing 2 to 6 carbon atoms is used to furnish the anionic group. The free acids can also be used, e.g., monochloroacetic acid, monobromoacetic acid or monochloropropionic acid but since the reaction is carried out under alkaline conditions the acids will be converted to salts, e.g., sodium, potassium, lithium, calcium, strontium, barium, and/or ammonium. Similarly, acids and salts of phosphorus can be used to introduce phosphate and phosphonate groups.
Examples of nitrogen etherifying agents suitable for introducing cationic groups are: 2-chlorotriethylamine; 2- chlorotriethylamine hydrochloride; Z-chloroethyldimethylamine; 2-chloroethyldimethylamine hydrochloride; 3-chloropropyldiethylamine; 3 chloropropyldiethylamine hydrochloride; 3 ch10ropropydimethylamine; 3 chloropropyldimethylamine hydrochloride; 4 chlorobutyldiethylamine; 4 chlorobutyldiethylamine hydrochloride; 2-chloroisopropyldimethylamine; 3 dibutylamino 1,2 epoxypropane; 2 bromo 5 diethylaminopentane hydrobromide, N (2,3 epoxypropyl) piperidine; N,N-(2,3-epoxypropyl)methyl aniline; 4 chloro 2 butenyltrimethyl ammonium chloride; and 2 hydroxy 3-chloropropyltrimethylamine chloride. In general, it is preferable to use the salts of the nitrogen esterifying agents, such as, for example, the hydrochlorides and the hydrobromides. Mixtures of nitrogen etherifying agents can be employed. The salts should be selected so as to avoid formation of precipitates. For example, if calcium, strontium or barium is present, sulfates or phosphates should not be used because insoluble salts, such as calcium sulfate or calcium phosphate, would form. However, sulfates or phosphates of the quaternary amines can be used where sodium, potassium or lithium ions are present.
If the cationic cyanamide groups are introduced into the starch molecule a cyanamide compound is used, e.g., calcium cyanamide or hydrogen cyanamide (H NCN).
The alkylene oxide, the anionic reactants and the cationic reactants react with the starch under basic conditions. The reaction can be carried out at ordinary or slightly elevated temperatures below the temperature at which the starch gelatinizes, for example, within the range of 35 F. to F. In order to obtain uniform reaction, it is desirable to mix the reactants with a solvent, preferably water. Other solvents, .for example, acetone, can be used but they are more expensive and in some cases present problems in recovering the product. The product is ungelatinized and insoluble in water and therefore can be recovered as a granular solid by filtration, washing with water and drying.
The invention will be further illustrated but is not limited by the following examples in which the quantities are stated in parts by weight unless otherwise indicated.
Example 1 (a) A slurry of 5000 grams of ungelatinized Amylomaize VII in 7 liters of water containing 250 grams sodium sulfate (Na SO was prepared. 75 grams of sodium hydroxide were dissolved in 1 liter of water and 250 grams sodium chloride was added. Each mixture was cooled to the ambient temperature (78 F.) and the mixture containing sodium chloride was stirred into the starch slurry containing the sodium sulfate.
The resultant slurry was diluted to 14 liters with water. It had a pH of 11.2 and a conductivity of 640 micromhos at 78 F. 300 grams of ethylene oxide and 100 grams of 1,2-propylene oxide were stirred into the mixture. The resultant mixture had a pH of 11.2 and a conductivity of 1460 mmhos at 80 F. After 1 hour, the mixture was divided into .two equal parts which were labelled 20.1 and 20.2.
(b) In the portion of the mixture labelled 20.1, 37.5 grams of 2-chloroethyldiethylamine hydrochloride dissolved in 50 cc. of water were added with stirring at 76 F. To the resultant mixture there was gradually added 12.5 grams propane sultone. The mixture was allowed to react for 45 hours at 76 F. The pH was then adjusted to 3.5 by adding 130 cc. of 6 normal HCl. The product was filtered, reslurried in liters of water; filtered, reslurried in 10 liters of water again; filtered, reslurried in 5 liters of water and the pH adjusted to 3.5. The resultant product Was then filtered and dried.
(c) To the portion of the mixture labelled 20.2, there was added gradually 250 cc. of a 50% aqueous solution of H NCN at 75 F. To the resultant mixture there was gradually added 12.5 grams propane sultone. The mixture was allowed to react for 45 hours at 75 F. It was then processed as in (b) except in the last slurry 5 grams of aluminum sulfate was added. After 2 hours the last slurry was then filtered and dried.
In Example 1(a) the nitrogen content of the product on a dry basis was 0.18. The proportion of 2-ethyldiethylamine hydrochloride was 1.5% and the proportion of propane sultone was 0.5%.
-In Example I(b) the nitrogen content of the product was 0.51%, the quantity of hydrogen cyanamide was 4% (8% of a 50% solution).
Example H A slurry was prepared by mixing together 50,000 pounds of a starch of the type described in Example 1, 2500 pounds sodium sulfate, 3600 pounds sodium chloride, 300 pounds sodium bisulfite, 768 pounds sodium hydroxide, 2500 pounds ethylene oxide and suflicient water to make 18,500 gallons of slurry. The mixture was allowed to react for 24 hours at approximately 83 F. After 24 hours it had a pH of 11.2 and a conductivity of 1950 mmhos. Then 750 pounds of 2-chloroethyldiethylamine hydrochloride dissolved in 10 gallons of water (1.5% 2-chloroethyldiethylamine hydrochloride on the dry weight of the starch) was poured into the slurry. The slurry had a pH of 11 and a conductivity of 2050 mmhos at 82 F. Next, 250 pounds propane sultone (0.5% on the dry Weight of the starch) was dripped into the slurry. The slurry had a pH of 11.2 and a conductivity of 5700 mmhos at 82 F.
The mixture was allowed to react for 24 hours at 76- 82 F. after which it had a pH of 11.2 and a conductivity of 7000 mmhos. The pH was adjusted to 3.5 with 6 N HCl and the slurry filtered, washed and dried. In the slurry just before the drier, a titration of 35 mls. of the slurry showed a pH of 3.5 and a conductivity of 570 mmhos at 78 F.
The dry granules analyzed 87.2% moisture free solids, 0.15% ash on a dry basis, 0.24% nitrogen on a dry basis.
6 The NCV viscosity of 48.6 grams was 32.0 seconds. The pH of the paste made .from these granules was 4.6 and the isoelectric pH was 8.3.
Example III The procedure was the same as in Example II except that 8% of a 50% aqueous solution of H NCN based on the dry weight of the starch was substituted for the 2-chloroethyldiethylamine hydrochloride.
Example IV (a) A starch of the type described in Example I was mixed with 5% sodium sulfate, 1.5% sodium hydroxide, 5% sodium chloride, and 7% ethylene oxide, with sufficient water to form 3700 gallons of slurry and the slurry was allowed to react for 48 hours at 7 8 F.
(b) 150 pounds of calcium hydroxide was slurried in 500 pounds of water and stirred into the slurry prepared as in (a). To the resultant mixture was added at 96 F. 150 pounds 2-chloroethyldiethylamine hydrochloride dissolved in 500 pounds water. Next 50 pounds of propane sultone was dripped into the slurry at F.
After 24 hours reaction at 95-100 F. the pH of the slurry was adjusted to 4 with 6 N HCl. The solids were washed and filtered twice and then dried. This product had a nitrogen content of 0.16% on a dry basis. The NCV viscosity of 0.3 anhydroglucose unit was 14 seconds. The isoelectric pH was 9.3.
Example V A starch was oxyethylated as described in Example IV(a) and prepared as a dry product. 5000 grams of this product was slurricd with 8 liters of water and then diluted to 12 liters with Water. 150 grams of calcium hydroxide in 500 cc. of water was stirred into the slurry at a temperature of 84 F. 150 grams of 2-chloroethyldiethylamine hydrochloride dissolved in 50 cc. water was stirred into the mixture and then 50 grams of propane sultone was dripped into the mixture. The mixture was divided into two equal portions.
One portion was allowed to react for 22 hours at an average temperature of 74 F. The pH was then adjusted by adding 226 cc. of 6 N hydrochloric acid. The solids were filtered, reslurried in 5 liters of water; filtered, reslurried in 5 liters of water; filtered, reslurried in 2.5 liters of water; and then filtered and dried.
The resultant product contained 97% solids, 0.20% nitrogen on a dry basis, 0.11% ash on a dry basis. At a concentration of 0.3 AGU, the NCV viscosity was 9 seconds.
Example VI The procedure was the same as in Example V except that the oxyethylated high amylose starch in proportions of 5000 grams to 8 liters of water, diluted to 12 liters with water, was divided into two equal portions labelled 13.3 and 13.4.
To the portion 13.3 was added 75 grams calcium hydroxide slurried in 250 ml. water, then 75 grams of 2- chloroethyldiethylamine hydrochloride in 25 ml. of water was stirred into the slurry. Thereafter 25 grams of propane sultone were added gradually. The mixture was allowed to stand at 78 F. for 22 hours and the pH was adjusted by adding 212 cc. of 6 N hydrochloric acid.
The product was then recovered as described in Example V. This product contained 82.4% solids, had a nitrogen content of 0.25% on a dry basis, and 58 grams gave an NCV viscosity of 10 seconds.
Portion 13.4 was processed in the same manner as por tion 13.3 except that 37.5 grams of calcium hydroxide in cc. of water, 37.5 grams of 2-chloroethyldiethylamine hydrochloride in 25 cc. of water, and 12.5 grams of propane sultone were used.
The product was recovered in the same manner as in Example V. It contained 87.2% solids and a nitrogen content of 0.18%, and 55.7 grams had an NCV viscosity of .19 seconds at 72 F.
Example VII 5000 grams of the starch described in Example I were slurried in 7 liters of water and then diluted to 12 liters with water. 110 grams of calcium hydroxide in 500 cc. of water were stirred into the slurry. 500 grams of propylene oxide were poured in slowly. After 4 hours, 172 grams of 2-chloroethyldiethylamine hydrochloride in 200 cc. of water were stirred into the slurry, and then 31 grams of propane sultone was stirred in slowly. These operations were conducted at temperatures of from 80'- 84 F. The temperature was then adjusted to 130 F. and the mixture allowed to react for 17 hours at a temperature of 130-135 F. The pH was then adjusted to 4 with 207 cc. of 6 N hydrochloric acid. The slurry was filtered; the solids were reslurried in 10 liters 'of water; filtered, reslurried in 10 liters of water; filtered and reslurried in liters of water; filtered and dried. The product was an oxypropylated starch containing both basic and acidic groups.
It is advantageous, in accordance with the invention, to provide in the starch slurry prior to addition to the sultone and the etherifying agent, an alkaline earth metal base, such as calcium hydroxide, barium hydroxide or strontium hydroxide. The temperature for reaction of the sultone and the etherifying agent is, in general, room or ambient temperature or temperatures slightly above or below, i.e., a temperature range of about 60 F. to 120 F. Where the alkaline earth metal base is employed, the resultant sulfonic acid groups on the sultone will be in whole or in part the alkaline earth metal sulfonate.
The products prepared as previously described were used at their isoelectric point. At this point they contain no charge. However, they can be prepared by separating them without neutralizing with hydrochloric acid or other acidic substances, thereby giving a product having a pH in the range of to 11 due to the fact that calcium oxide or hydroxide was present during its preparation. Such a product has a negative charge and is anionic. Hence, it will attract substances which are positively charged, such as basic dyes, cationic melamine-formaldehyde resins, and other cationic resins.
The products can also be prepared so as to have a pH below the isoelectric pH. This can be done, for example, by adding hydrochloric acid until the pH is around 1 and then raising it to about 4 with NaOH or other alkaline substance and separating the resultant product, The product in this case is cationic and when employed in a coating composition, will have an aifinity for negatively charged substances, such as acid dyes, acidic resins, e.g., polyester resins, and other acidic resins.
A simple method for determining whether the product is neutral, anionic or cationic is to test an ungelatinized slurry of the product with methylene blue basic dye (Color Index No. 52015) and light green SF yellowish acid dye (Color Index 42095). The cationic products will accept the acid dye. The anionic products will accept the basic dye and no dyeing occurs with either product at the isoelectric point.
The proportions of cationic reactant and anionic reactant used in the process are subject to variation but are preferably in a molar ratio within the range of 1:3 to 3:1, usually around 1:1. An excess of either reactant can be present. As the examples show, the cationic groups and anionic groups do not necessarily react with the starch in the proportions in which they are used in the process. The number of cationic groups normally exceeds the number of anionic groups, the ratio of cationic groups to anionic groups preferably being at least 1511, and a preferred range being 1.75:1 to 3:1.
Sizing of textile fibers-In the sizing of textile fibers a typical sizing composition can be prepared by mixing pounds of an amphoteric starch prepared in accordance with this invention with 100 gallons of water, preferably with the addition of five pounds of petroleum wax, and then heating to the gelatinization temperature. The thread or yarn to be sized, for example, a thread or yarn containing 65% polyester fiber (polyethylene glycol terephthalate), and 35% cotton fibers, is then sized by passing it through this composition.
In using this sizing composition, the number of yards of woven material between changes of loom stops can be increased. After weaving, the sizing material can be removed by washing with a detergent water.
The following example is given to illustrate the application of the invention in the sizing of textile fibers.
Example VIII A composition was prepared as described in Example VI under 13.4. 200 pounds of this composition was mixed with gallons of water and 8 pounds of petroleum wax to form a composition which was then cooked for one hour at 210 F. The resultant composition had a viscosity of 4.5 seconds (Zahn cup). It was placed in a storage tank and held at a temperature of 190 F. A refractometer reading showed that it contained 8% solids. This composition was then introduced into a size box for sizing textile yarns and held at a temperature of 180 F. A yarn having a denier of 15 and consisting of 50% polyester fibers and 50% cotton fibers was then passed through the size box and sized at the rate of 55 yards per minute. The yarn was woven into cloth on a loom with excellent results.
In a similar manner, other natural fiber and/or synthetic polymer yarns can be sized with the compositions of the invention, including nylon yarns, polyester yarns, polyacrylonitrile, rayons and yarns of other synthetic fibers or blends thereof with natural fibers, for example, cotton and wool. The invention is especially useful in sizing synthetic fibers which are very difficult to size, such as Nomex nylon.
The compositions of the invention can also be employed in other uses, for example, in the finishing of textiles, in dyeing textiles and paper, in the sizing of paper, in the application of pigments or coatings to cloth and paper, in coating polyolefins, as a coagulating agent in the separation of finely divided mineral particles from ores or water, in sedimentation, and for a wide variety of other purposes.
The term oxyalkylated stare as used herein refers to a starch which has been reacted with an alkylene oxide. For the purpose of the present invention, the alkylene oxide should contain two to four carbon atoms in the alkylene group. It is believed that the addition of the oxyalkylated groups to the starch molecule makes the starch more reactive, especially where high amylose starches are used and the process is therefore particularly important in making high amylose starches containing non-ionic, cationic and anionic groups.
The NCV viscosity is determined by preparing a sample of the starch product by mixing 0.3 AGU of the starch product in 400 cc. of water, cooking for 30 minutes with agitation on a boiling water bath, then while the composition is still hot, withdrawing a 50 cc. pipette of the material and determining the time required for the 50 cc. to fiow from the pipette.
The invention is hereby claimed as follows:
1. A composition comprising an ungelatinized granular oxyalkylated starch in which the pH has been adjusted to the isoelectric pH, said starch containing oxyalkylene groups having 2 to 4 carbon atoms and having both cationic and anionic groups connected to the starch molecules through carbon and oxygen, the oxyalkylene groups constituting 10 to 36 groups per 100 anhydroglucose units, and the cationic and anionic groups each constituting 0.5 to 6 groups per 100 anhydroglucose units,
said cationic groups being from the class consisting of tertiary amino, tertiary amine salt, quaternary amino, quaternary amine salt and cyanamide and said anionic groups being from the class consisting of sulfonic, sulfonate, carboxylic, carboxylate, phosphate and phosphonate.
2. A composition as claimed in claim 1 in which said pH has been adjusted to a pH above the isoelectric pH until the product is anionic.
3. A composition as claimed in claim 1 in which said pH has been adjusted to a pH below the isoelectric pH until the product is cationic.
4. A composition as claimed in claim 1 in which the ratio of cationic groups to anionic groups is within the range of 3:1 to 1:3.
5. A composition as claimed in claim 1 in which the amylose content of said starch is at least 50% by weight.
6. A composition as claimed in claim 1 in which the oxyalkylene groups are oxyethylene groups.
7. A composition as claimed in claim 1 in which the oxyalkylene groups are oxypropylene groups.
8. A composition as claimed in claim 1 in which the oxyalkylene groups are both oxypropylene groups and oxyethylene groups.
9. A composition as claimed in claim 1 in which said anionic groups are from the group consisting of sulfonic and sulfonate.
10. A composition as claimed in claim 9 wherein said sulfonic acid and said sulfonate contain a radical of the formula R SO X wherein R is alkylene of 3-4 carbons and X is hydrogen, sodium, potassium, lithium, ammonium, calcium, strontium or barium.
10 11. A composition as claimed in claim 1 in which said cationic groups contain a radical of the formula R1 R--N R2 wherein R is alkylene of 2-6 carbons, and R and R are alkyl of 1-6 carbons.
12. A composition as claimed in claim 1 in which said cationic groups are ethylene diethylamine groups connected through carbon of the ethylene group and oxygen to the starch molecule and said anionic groups are -R --SO X wherein R is alkylene of 3-4 carbon atoms connected through oxygen to the starch molecule, and X is hydrogen or sodium.
13. A composition as claimed in claim 1 in which said cationic groups are cyanamide groups.
14. A composition as claimed in claim 1 in which said cationic groups are quaternary amino in which the hydrocarbon groups attached to the amino nitrogen contain 1-6 carbon atoms.
References Cited UNITED STATES PATENTS 3,622,563 11/1971 Elizer 260-233.3 R 3,650,787 3/1972 Elizer 260233.3 R
DONALD E. CZAJ A, Primary Examiner M. I. MARQUIS, Assistant Examiner US. Cl. X.R.
1062l3; 117-1395 C; 260233.3 A, 233.5