Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
  • C08B31/00—Preparation of derivatives of starch
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
  • C08B30/00—Preparation of starch, degraded or non-chemically modified starch, amylose, or amylopectin
  • C08B30/12—Degraded, destructured or non-chemically modified starch, e.g. mechanically, enzymatically or by irradiation; Bleaching of starch
  • C08B30/14—Cold water dispersible or pregelatinised starch
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/16—Organic compounds
  • C11D3/20—Organic compounds containing oxygen
  • C11D3/22—Carbohydrates or derivatives thereof
  • C11D3/222—Natural or synthetic polysaccharides, e.g. cellulose, starch, gum, alginic acid or cyclodextrin
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P19/00—Preparation of compounds containing saccharide radicals
  • C12P19/14—Preparation of compounds containing saccharide radicals produced by the action of a carbohydrase (EC 3.2.x), e.g. by alpha-amylase, e.g. by cellulase, hemicellulase
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/54—Starch

Definitions

• the present invention relates to high solids, high molecular weight cooked starch dispersions and to the stability and molecular weight distribution of these high solids dispersions at a given solids and viscosity when cooked and thinned using the teachings presented herein. More specifically, the invention relates to the use of a jet cooker to gelatinize and promote the enzyme thinning of derivatized starches.
• stability of a cooked starch dispersion is related to the solids of the dispersion, the ratio of the amylose (linear) fraction to the amylopectin (branched) fraction of the starch molecules, the type and degree of substitution and the amount of depolymerization of the starch, particularly the amylose fraction.
• the increase in the viscosity of cooked starch paste is a function of the alignment of the carbohydrate chains and the hydrogen bonding that occurs between adjacent hydroxyls on these chains. Anything that interferes with this alignment or the hydrogen bonding, will retard setback and the increase in viscosity that is normally seen as a cooked starch paste cools and ages.
• 5,612,202 relates to a two step process for thinning a starch and producing a low dextrose equivalent (DE) maltodextrin consisting of a first step of enzyme thinning the starch to a DE of from about 10 to 30.
• DE dextrose equivalent
• This is equivalent to a molecular weight of the branched (amylopectin) fraction of the starch of between 50,000 and 20,000 daltons and a low molecular weight (less than 5,000 daltons) linear fraction.
• the concentration of the high molecular weight amylopectin fraction having a molecular weight greater than 1,000,000 daltons is less than 4% by weight.
• a stable low DE product is then produced by removing the low molecular weight amylose fraction to yield a molecular weight fraction with a molecular weight from about 20,000 to about 50,000 daltons, a concentration of from about 70% to about 100% and a D.E. between 2 and 8.
• Practice of the method of Brumm results in extensive degradation of the high molecular weight (greater than 1,000,000 daltons) amylopectin portion of the starch to levels of less than 4% by weight.
• U S Patent No 5,003,022 discloses stable, high solids, starch copolymer dispersions characterized by improved strength at intrinsic viscosities lower than 0 12 dl/g Because of these lower intrinsic viscosities, they were able to use lower levels of smaller substituents (such as ethylene oxide) on the starch at relatively low concentrations to produce these dispersions
• the second major disadvantage of acid modification is that it is performed at the starch producer and not at the mill Because a large paper mill will generally need a number of different starches with different solids and viscosity requirements, mills must have storage for different starches at the mill.
• a size press starch is generally not the same viscosity and solids as a coating starch and size press and coating starches for different paper grades can also have different viscosity and solids requirements. If the mill does not want to store all of the different starches it needs for each use, it must compromise on the starches it purchases to reduce the number of different starches it must store.
• the third major disadvantage to acid modification relates to the loss of soluble starch that occurs as a result of the acid modification process.
• the acid modification of the starch granule produces a certain amount of low molecular weight, soluble starch.
• This low molecular weight starch is subsequently lost during the washing and filtering of the granular product. These losses range from 0.5% for lightly thinned starches to up to 15% for highly thinned starches.
• this starch has also been derivatized, the derivatization is generally done in the granular state before the acid modification. It is thus derivatized material that is lost during the acid modification.
• the present invention provides jet cooked, enzyme-thinned, derivatized starch dispersions and products made from these dispersions which are characterized by improved stability when compared to thinned derivatized starch dispersions made using conventional acid thinned or enzyme thinned or a combination of acid and enzyme thinning.
• the invention provides for uses for these improved products.
• the invention provides a method of preparing a stable enzyme- thinned starch dispersion characterized by a selected degree of thinning comprising the steps of: (a) combining a derivatized granular starch with an alpha-amylase enzyme to form a starch/enzyme slurry; (b) passing said starch/enzyme slurry through a jet cooker under conditions selected to gelatinize the starch; (c) treating the starch/enzyme slurry to complete gelatinization and achieve the selected degree of thinning such that the concentration of starch hydrolyzate product having a molecular weight greater than 1,000,000 daltons is 5% or greater or more preferably 8%> or greater; and (d) deactivating the enzyme.
• step (b) is carried out under conditions such that the alpha- amylase enzyme is not completely inactivated wherein the originally added enzyme can promote continued thinning of the starch.
• the jet cooking is carried out at a temperature greater than 212°F with jet- cooking temperatures of about 235 °F being particularly preferred. While it is generally desired that the starch component of the starch/enzyme slurry be substantially or completely gelatinized in the jet cooker the gelatinization of the starch enzyme slurry may be completed in a plug flow continuous reactor. Moreover, such a plug flow reactor (also known as a hold column) functions to continue the enzyme hydrolysis of the derivatized starch that was initiated in the jet cooker.
• a plug flow reactor also known as a hold column
• Hold times in the plug flow reactor can range from 10 seconds to up to 30 minutes but hold times ranging from 2 to 20 minutes are preferred with hold times of about 5 minutes being particularly preferred.
• the temperature of the plug flow reactor is held above 212°F with input and output temperatures of about 235°F being particularly preferred.
• the starch/enzyme slurry which has been treated in the jet cooker may be further treated to achieve the selected degree of thinning in a semi-batch reactor which can be a stirred reaction vessel.
• a semi-batch reactor which can be a stirred reaction vessel.
• Such a vessel is preferably held at atmospheric pressure but may be heated or cooled in order to optimize the enzyme activity.
• the use of a semi-batch reactor differs from that of a plug flow reactor in which each quantity of starch enzyme slurry is reacted for the same amount of time and under the same conditions.
• the combination of jet cooker and plug flow reactor thereby produces a thinned starch which has been uniformly treated.
• a slurry containing water, a derivatized starch and enzyme is passed through a jet cooker (hydroheater) and a short hold column.
• the mixture may be passed through a second jet cooker and the enzyme deactivated or the partially thinned pasted starch enzyme mixture is collected in a stirred vessel.
• This pasted starch/enzyme mixture would then be collected over a period of time during which the starch would continue to thin in the stirred vessel.
• a deactivating agent usually sodium hypochlorite
• the starch enzyme mixture is added to the starch enzyme mixture to deactivate the enzyme or the mixture can be passed through a second jet cooker at a much higher temperature to deactivate the enzyme.
• a deactivating agent usually sodium hypochlorite
• the enzyme-thinned starches of the present invention be exclusively enzyme thinned, it is recognized that minor amounts of acid thinning will not fundamentally change the character of the resulting improved products. Accordingly, the term "enzyme-thinned" will not exclude light acid modification which does not result in greater than a 1% solids by weight soluble loss if the remaining thinning is carried out by enzymatic means.
• enzyme-thinning according to the invention is primarily by means of alpha-amylases
• additional thinning may be carried out by use of enzymes such as beta-amylases, glucoamylases, alpha- glucosidases, isoamylases, amylo-1, 6-D-glucosidases, pullanases and the like.
• the present invention provides methods and products which avoid many of the limitations associated with the acid modification of starch.
• the cooked starch paste is enzyme thinned instead of acid modifying the starch granule.
• the low molecular weight material that is produced during the thinning step will remain with the cooked paste such that sewer losses of the soluble products are minimized.
• the only chemicals needed to enzymatically thin the starches are a small amount of enzyme and a small amount of calcium to stabilize the enzyme.
• the jet cooked, enzyme thinned, derivatized starch pastes of the invention may also be used as the starting material to manufacture starch copolymer materials for use in the paper, textile and other industrial processes and products.
• starch copolymers not only need thinned derivatized products with specific viscosity ranges, they also need starches that will produce products with adequate strength and viscosity stability.
• alpha amylases may be used according to the invention it is particularly preferred according to one aspect of the invention that the alpha-amylase be a high temperature alpha-amylase in order that elevated temperatures may be used in the jet cooker and any subsequent reactors.
• a particularly preferred high temperature alpha- amylase is derived from a modified strain of Bacillus licheniformis and is characterized by optimum activity at a temperature of from 92°C to 98 °C.
• the improved dispersions of the invention can be produced even if the starch is derivatized with a relatively low level of a small molecule.
• These stable, high solids cooked starch pastes have applications in a number of different areas.
• the invention also provides size press coatings, coating color compositions, concrete additives and adhesive compositions comprising the starch dispersions of the invention.
• the stable, high solids, cooked pastes are particularly useful as size press starches on a paper machine. This is especially true for mills that require high solids low viscosity pastes, but would like the higher strength associated with a less thinned, higher viscosity, lower solids product.
• the dispersions of the invention are useful in the manufacture of high solids starch copolymer dispersions that exhibit almost no increase in viscosity over time, particularly when compared to dispersions that are made with similar starches that are not thinned using the methods of this invention.
• These stable, high solids, cooked pastes are also useful in the manufacture of a high solids, dual derivative starch paste used in the emulsification of sizing compounds for the wet end of a paper machine. These pastes are particularly useful when shipped to the mill as precooked, ready to use dispersions, eliminating the need for cooking equipment at the mill.
• These dual derivative dispersions can contain an emulsified sizing compound such as AKD or other novel sizing compounds, or they can be shipped to the mill without the sizing agent and used at the mill to emulsify the sizing agents. Emulsification at the mill is particularly important for sizing agents such as ASA that are more sensitive to hydrolysis.
• Fig. 1 is a graph which depicts the molecular weight distribution of an enzyme-thinned derivatized starch of the invention compared with an acid-thinned derivatized starch which has been thinned to approximately the same initial viscosity at similar solids.
• the invention provides improved thinning methods and compositions comprising using a jet cooker and auxiliary equipment to cook and thin an enzyme containing, derivatized starch slurry, especially starches derivatized with smaller, less costly and easier to use reagents.
• starch dispersions of the present invention differ from those produced by acid modification or the combination of acid and enzyme hydrolysis with respect to the distribution of starch hydrolyzate products having molecular weights of less than 1,000,000 daltons.
• Native starches contain both amylopectin and amylose molecules, depending on the origin of the starch, the relative amount of amylopectin to amylose will vary from almost 100%> (as in waxy corn starch), to less than 20%> (as in high amylose corn starch).
• the typical ratio of amylopectin to amylose in native starches is about 80%> amylopectin to about 20%> amylose.
• GPC analytical gel permeation chromatography
• the large, highly branched molecules appear as a group of peaks at molecular weights of greater than about 1,000,000 daltons and the shorter, more linear molecules show up as a peak or peaks at molecular weights of less than 1,000,000 daltons.
• the relative amounts of the starch hydrolyzate products represented by these peaks have been found to be important when comparing the products of the present invention with those of either acid modified starches or starches which have been thinned using a combination of acid and enzyme hydrolysis.
• Fig. 1 depicts the molecular weight distributions of an enzyme-thinned derivatized starch according to the invention (which is the enzyme thinned starch of Example 5) and an acid modified derivatized starch equivalent to that produced in comparative Example 6 which have been thinned to approximately the same initial viscosity at the same solids.
• the enzyme- thinned derivatized starch according to the invention is characterized by having a molecular weight of 1,000,000 daltons and less which is characterized by a bimodal distribution wherein the enzyme thinned dispersion of the invention is characterized by having a relatively lower concentration of starch hydrolyzate products at the mode molecular weight of said corresponding acid thinned dispersion (which is represented by the peak between 0 and 1,000,000 daltons on the plot of the acid-thinned material in Fig.
• the enzyme thinned dispersion of the invention is characterized by having a relatively lower concentration of starch hydrolyzate products in the molecular weight range of from 10,000 to 250,000 daltons; a relatively greater concentration of starch hydrolyzate products in the molecular weight range of from 250,000 daltons to 1,000,000 daltons; and a relatively greater concentration of starch hydrolyzate products in the molecular weight range of from 0 to 10,000 daltons when compared to said exclusively acid thinned dispersion of identically derivatized starch.
• the products of the present invention are characterized by relatively more of short linear hydrolyzate products having molecular weights of less than 10,000 daltons than result from an equivalent degree of acid hydrolysis but relatively fewer linear hydrolyzate products having molecular weights between 10,000 daltons and 50,000 daltons than from acid hydrolysis.
• the products of the present invention comprise relatively more "amylose-like" starch hydrolyzate products having molecular weights between 50,000 daltons and 1,000,000 daltons which products are primarily linear but comprise short 1,6- branches many of which were not cleaved by the alpha amylase.
• starch dispersions of the present invention are characterized by improved stability and functional properties wherein dispersions comprising the enzyme thinned starches may be used at higher solids levels while maintaining their stability.
• the invention provides dispersions characterized by an as is solids content of greater than 30%) and more preferably 40%> by weight.
• Preferred starches include corn, potato, wheat, rice, tapioca and the like, with corn, potato and tapioca being especially preferred.
• the preferred derivatizing agents are ethylene oxide, propylene oxide, acetic anhydride, acrylonitrile, acrylamide, sodium monochloroacetate, tertiary and quaternary amines and combinations of these reagents.
• the derivatized starches of the invention may be substituted with a variety of moieties known to the art.
• Suitable functional derivative groups include alkyl, alkenyl, aryl, arylalkyl, arylalkenyl, cycloalkyl, and cycloal enyl ethers, hy droxy ethers, esters including organic acid esters, amides, ketones, acetals, and ketals, and derivatives thereof, carboxylates, phosphates, sulfates, sulfonates, amino, and quaternary ammonium groups, and combinations thereof.
• Preferred derivative groups include benzyl, allyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, and 2- hydroxy-3-butenyl ethers, formate, acetate, propionate, butyrate, dodecanoate, and stearate esters, alkenyl succinate esters, carboxylic acid, carboxy methyl, and carboxyethyl derivatives, and combinations thereof.
• a particularly preferred starch is hydroxyethyl starch.
• Especially preferred for starch substitution in the practice of the present invention are ethylene oxide, propylene oxide, quaternary amines and combinations of these reagents.
• ethylene oxide, propylene oxide and the quaternary amines are especially preferred because of their low cost on a mole basis and their relative ease of reactivity with granular starch in an aqueous system.
• the degree of substitution is very important when producing a stable high solids starch dispersion, the degree of substitution will vary with the type of starch, the type of substituent, the solids of the end product and the degree of depolymerization. It is the higher degree of stability seen through the practice of the present invention (jet cooking the enzyme/starch slurry) that allows the use of smaller, less costly reagents to produce high solids, high strength and sometimes high viscosity, stable thinned starch pastes and starch copolymer dispersions made from these pastes.
• the starch is a dual derivatized starch with dual derivative starches comprising the combination of cationic and nonionic moieties being preferred.
• Preferred nonionic moieties according to the invention are hydroxyalkyl moieties with preferred cationic moieties being tertiary and quarternary amine compounds with tertiary and quarternary substituted ammonium compounds being preferred.
• a particularly useful dual derivatized starch according to this aspect of the invention is propylated cationic starch.
• the dual derivative products of the invention are useful for a variety of purposes including but not limited to use as a component of a wet end sizing composition.
• Such wet end sizing compositions further comprise a sizing agent selected from the group consisting of ASA (alkenyl succinic anhydride), AKD (alkyl ketene dimer) and rosin.
• ASA alkenyl succinic anhydride
• AKD alkyl ketene dimer
• rosin rosin.
• Such dual derivative starches are also particularly useful as binder components of improved liquid laundry starches.
• the products of the invention may also be used as components of blends with synthetic polymers or as reaction products with one or more unsaturated monomers according to methods such as those of Nguyen et al., U.S. Patent No. 5,003,022 and Nguyen et al., U.S. Patent No. 5,416,181.
• Unsaturated monomers for reaction with starches can include, but are not limited to, styrene, p-methylstyrene, p-t-butylstyrene, p-methoxystyrene, vinyl toluene, vinyl naphthalene, and divinyl benzene; isobutylene, 4-methyl-l-pentene, 1 ,3 -butadiene, 2-methyl-l ,3-butadiene, 1 ,4-hexadiene, and 5- ethylidene-2-norbornene; acrylic acid, methacrylic acid, itaconic acid, and their C to C 18 alkyl, cycloalkyl, alkenyl, aryl, arylalkyl, and arylalkenyl esters; methyl acrylate, ethyl aery late, n-butyl acrylate, i-butyl aery late, 2-ethy
• a stable high viscosity 30% solids dispersion comprising an enzyme thinned dual derivative starch was prepared according to the methods of the present invention Specifically, a potato starch derivatized with both propylene oxide and a quarternary amine was thinned through a jet cooker using a high temperature enzyme Specifically, 750 pounds ds basis native potato starch (Penford Products Co , Cedar Rapids, IA) was reacted with propylene oxide and (3-chloro-2- hydroxypropyl) trimethylammonium chloride to produce a dual derivative potato starch containing about 2 1% by weight hydroxypropyl substitution and 0 37% by weight nitrogen equivalent to a total degree of substitution of about 0 11 This starch was washed and reslurried in water to a Be' Tc of 18 3 which was equivalent to about 32 5% solids ds basis The temperature of the slurry was about 84 °F and the pH was about 6 8 To this slurry was added
• alpha amylase (Spezyme AA-L Heat Stable Alpha- Amylase
• TAU is defined as the quantity of enzyme that will dextrinize one milligram of starch per minute at a pH 6.6 and 30 °C under specific assay conditions.
• a fixed displacement pump was used to pump the slurry through a jet cooker at a rate of 4.7 gallon/min. at 235-240 C F cooked paste temperature measured in line just after the cooked paste had passed through the jet cooker.
• the starch paste was cooked through a 4" diameter by 10' hold column (plug flow/continuous reactor) into a 1000 gallon stirred semi-batch reactor. Starch was cooked into the reactor for a total of about 50 minutes. At this time, about 2100 ml of 16% sodium hypochlorite was added to deactivate the enzyme.
• a sample was taken and analyzed according to the procedures described below. Rapid Visco Analyzer Test Method
• This test method utilizes the Rapid Visco Analyzer (RVA) to analyze starch samples during a starch cook and thinning.
• RVA Rapid Visco Analyzer
• the Newport RVA Series 4 instrument (Newport Scientific Pty., 1/2 Apollo Street, Warriewood NSW 2102, Australia) has made possible the development of specific time and temperature dependent viscosity profiles indicative of various levels of enzymatic hydrolysis. This method can provide a quick and relatively simple comparison to known products that have been enzymatically hydrolyzed using the same or similar thinning methods.
• Viscosity for the enzyme-thinned starch using the RVA at the above conditions was initially 975 cp and 1132 cp after storage of the starch at 23 °C for 2 months.
• Size Exclusion Chromatography of Aqueous Starch Suspensions Size exclusion chromatography of starch dispersions in water can allow one skilled in the art to infer about the approximate molecular weight distributions of amylose and amylopectin in the cooked starch suspension.
• a calibration curve using water-soluble pullulans of known molecular weight was prepared using Shodex P-82 Standards (distributed by Phenomenex Inc., 2320 W.
• Examples 2-6 set out below illustrate the use of stable, high solids, derivatized, cooked starch dispersions of the invention to produce starch copolymers.
• Examples 2 and 3 illustrate the use of these dispersions to produce 50%> solids starch copolymers and Example 5 illustrates the use of these dispersions to produce a 30%> dispersion.
• Examples 4 and 6 are acid modified controls for Examples 2, 3 and 5.
• EXAMPLE 2 According to this example, an enzyme-thinned starch according to the invention was used to produce a styrene/butadiene starch copolymer.
• an ethylene oxide derivatized cornstarch is enzyme thinned and reacted with styrene and butadiene to produce a 50% solids starch grafted copolymer for use as a binder in paper applications.
• ® ppm Ca ++ 580 g (0.080% by weight based on ds starch) alpha amylase (Spezyme AA-L Heat Stable Alpha- Amylase, Genencor International) with an activity of 5650 TAU/g.
• a fixed displacement pump was used to pump the slurry through a jet cooker at a rate of 5.9 gallon/min. at about 235 °F cooked paste temperature measured in line just after the cooked paste had passed through the jet cooker.
• the starch paste was then cooked through a 4" diameter by 10' hold column (plug flow continuous reactor) with a hold time of about 1.5 minutes, into a 1,000 gallon stirred reactor. Starch was cooked into the reactor for a total of about 80 minutes.
• Samples were taken and analyzed at ten minute intervals starting at 90 minutes after the start of the cook according to the following procedure: A 300 gram sample was collected at each interval and the enzyme deactivated with about 0.5 g of 16% sodium hypochlorite and analyzed according to the RVA procedure described previously. When the proper degree of thinning had been obtained, about 4.5 liters of 16%> sodium hypochlorite was added to deactivate the enzyme. The final thinned paste had a 40 C F RVA viscosity of 102 cp.
• the enzyme-thinned starch was cooled down to about 120°F and about 40 pounds of sodium persulfate was added to the stirring cooked paste.
• the agitator was stopped and about 870 pounds of styrene and 623 pounds of butadiene were added.
• the agitator was restarted and the mixture was heated to about 158°F and reacted for about 7 hours
• the reactor was vented and 12 pounds of sodium persulfate was added.
• the mixture was allowed to react about 5 more hours and the pH was adjusted to about 6.2 with a combination of sodium hydroxide and sodium carbonate.
• About 1.5 liters of Kathon LX was added as a biocide.
• the enzyme-thinned starch copolymer composition of the invention was used as a binder in a coating color composition to coat paper Specifically, a coating color composition comprising the components of Table 1 was produced according to the following method
• the coating color composition was prepared by first adjusting the pH of the starch copolymer to 5.0-6 5 The starch copolymer was then added to the predispersed clay slip consisting of a 71% solids mixture of 80 parts #1 Kaolin clay (Premier, ECC International) and 20 parts ground calcium carbonate (Carbitol 90, ECC International). The lubricant (Nopcoat C-104, Henkel) was added to the clay/starch copolymer mixture.
• EXAMPLE 3 According to this example, an enzyme-thinned starch according to the invention was used to produce a styrene/butadiene starch copolymer.
• an ethylene oxide derivatized cornstarch was enzyme thinned and reacted with styrene and butadiene to produce a 50% solids starch grafted copolymer for use as a binder in paper
• Penford Products Co. (2.69%> by weight ethylene oxide substitution) with a degree of substitution of 0.098 was slurried in water to a Be' Tc of 19.8 which was equivalent to about 35.2%o solids ds basis.
• the temperature of the slurry was about 92°F and the pH was about 6.2.
• To this slurry was added 268 g CaCl 2 -2 H 2 O (100 ppm Ca ++ ) and 578 g
• Alpha-Amylase Genencor International
• a fixed displacement pump was used to pump the slurry through a jet cooker at a rate of 5.9 gallon/min. at about 235 °F cooked paste temperature measured in line just after the cooked paste had passed through the jet cooker.
• the starch paste was cooked through a 4" diameter by 10' hold column with a hold time of about 1.5 minutes, into a 1,000 gallon stirred reactor. Starch was cooked into the reactor for a total of about 78 minutes. The starch continued to thin for an additional 131 minutes.
• Samples were taken and analyzed at ten minute intervals starting at 90 minutes after the start of the cook according to the following procedure.
• a 300 g sample was collected at each interval and the enzyme deactivated with about 0.5 g of 16% sodium hypochlorite and analyzed according to the RVA procedure described previously. After 209 total minutes from the start of the cook, the proper degree of thinning had been obtained and about 4.5 liters of 16% sodium hypochlorite was added to deactivate the enzyme.
• the final thinned paste had a 40 °F RVA viscosity of 104 cp
• the starch was cooled down to about 120°F and about 40 2 pounds of sodium persulfate was added to the stirring cooked paste.
• the agitator was stopped and about 888 pounds of styrene and 636 pounds of butadiene were added.
• the agitator was restarted and the mixture was heated to about 158°F and reacted for about 6.5 hours.
• the reactor was vented and 12 pounds of sodium persulfate was added.
• the mixture was allowed to react about 5 more hours and the pH was adjusted to about 6.6 with a combination of sodium hydroxide and sodium carbonate.
• About 1.5 liters of Kathon LX was added as a biocide
• the enzyme-thinned starch copolymer product of the invention was then used as the binder component of a paper coating color composition to produce a lightweight coated paper according to the method of Example 2
• the results of testing that coated paper are set out in Table 2 below
• EXAMPLE 4 This comparative example illustrates the preparation of a starch copolymer control using a highly acid modified and enzyme thinned ethylated starch
• an ethylene oxide derivatized cornstarch is reacted with styrene and butadiene to produce a 50%) solids starch grafted copolymer for use as a binder in paper applications
• the agitator was stopped and about 870 pounds of styrene and 623 pounds of butadiene were added.
• the agitator was restarted and the mixture was heated to about 158°F and reacted for about 7.0 hours.
• the reactor was vented and 11.8 pounds of sodium persulfate was added.
• the mixture was allowed to react about 5 more hours and the pH was adjusted to about 4.8 with a combination of sodium hydroxide and sodium carbonate.
• About 1.5 liters of Kathon LX (Rohm and Haas) was added as a biocide.
• the acid modified and enzyme-thinned starch copolymer product of the invention was then used as the binder component of a paper coating color composition to produce a lightweight coated paper according to the method of Example 2.
• the results of testing that coated paper are set out in Table 2 below.
• EXAMPLE 5 According to this example, an enzyme-thinned starch according to the invention was used to produce a starch copolymer.
• an ethylene oxide derivatized cornstarch was enzyme thinned and reacted with styrene and butadiene to produce a 30% solids starch grafted copolymer for use as a binder in paper applications.
• alpha amylase (Spezyme AA-L Heat Stable Alpha-Amylase
• a fixed displacement pump was used to pump the slurry through a jet cooker at a rate of 64 gallon/min. at about 235°F cooked paste temperature measured in line just after the cooked paste had passed through the jet cooker.
• the starch paste was cooked through a 12" diameter by 13' hold column with a back-pressure regulator to maintain a back pressure of about 50 psi and with a hold time of about 1 minute, into a 10,000 gallon stirred reactor.
• Starch was cooked into the reactor for a total of about 65.5 minutes. Two 750 g samples were collected at ten minute intervals starting at 90 minutes after the start of the cook.
• the enzyme was deactivated in each sample with about 1 g of 16%> sodium hypochlorite. Each sample was then analyzed according to the RVA procedure described above. When the desired degree of thinning was reached, about 38 liters of 16%> sodium hypochlorite was added to deactivate the enzyme. The final 40 °C RVA viscosity was 186 cp.
• the enzyme-thinned starch paste was diluted to about 19.9% solids with water and cooled down to about 120°F. About 150 pounds of sodium bicarbonate and about 330 pounds of potassium persulfate were added to the stirring cooked paste. The agitator was stopped and about 4772 pounds of styrene and 3266 pounds of butadiene were added. The agitator was restarted and the mixture was heated to about 160°F and reacted for about 5.5 hours. The reactor was vented and 50 pounds sodium bicarbonate and 110 pounds of potassium persulfate were added. The mixture was allowed to react about 5 more hours. The final pH was about 5.5. About 15 liters of Kathon LX (Rohm and Haas) was added as a biocide. Brookfield viscosity of the starch copolymer measured using a Brookfield #4 spindle at 100 rpm and 23 °C was 78 cp and after 6 days at 6°C, was 128 cp at 6°C.
• the enzyme-thinned starch copolymer product of the invention was then used as the binder component of a paper coating color composition to produce a lightweight coated paper according to the method of Example 2.
• the results of testing that coated paper are set out in Table 2 below.
• EXAMPLE 6 This comparative example illustrates the preparation of a starch copolymer control using a highly acid modified and enzyme-thinned ethylated starch.
• an ethylene oxide derivatized cornstarch was reacted with styrene and butadiene to produce a starch grafted copolymer for use as a binder in paper applications.
• ® 10,261 pounds ds ethylated acid-thinned cornstarch (Pen-cote starch, Penford Products Co.) (about 2.0% by weight ethylene oxide substitution) with a degree of substitution of about 0.075 was slurried in water to a Be' Tc of 11.9 which was equivalent to about 20.0% solids ds basis.
• the temperature of the slurry was about 104°F and the pH was about 6.5.
• a fixed displacement pump was used to pump the slurry through a jet cooker at a rate of 64 gallons/min. at about 235 °F cooked pasted temperature measured in line just after the cooked paste had passed through the jet cooker.
• the starch paste was cooked through a 12" diameter by 13' hold column into a 10,000 gallon stirred reactor. Starch was cooked into the reactor for a total of about 81 minutes. The starch was cooled down to about 120 C F. About 150 pounds of sodium bicarbonate and about 330 pounds of potassium persulfate were added to the stirring cooked paste. The agitator was stopped and about 4309 pounds of styrene and 3078 pounds of butadiene were added. The agitator was restarted and the mixture was heated to about 160°F and reacted for about 5.5 hours. The reactor was vented and 50 pounds sodium bicarbonate and 110 pounds of potassium persulfate were added.
• the mixture was allowed to react about 5 more hours and the pH was adjusted to about 4.8 with sodium carbonate and about 15 liters of Kathon LX (Rohm and Haas) was added as a biocide. Brookfield viscosity of the starch copolymer measured using a Brookfield #4 spindle at 100 rpm and 23 °C was 552 cp and after 6 days at 6°C, was 1376 cp at 6°C.
• the acid-thinned starch copolymer product of the invention was then used as the binder component of a paper coating color composition to produce a lightweight coated paper according to the method of Example 2.
• the results of testing that coated paper are set out in Table 2 below which reports the average results of sixteen experimental runs.
• EXAMPLE 7 This example illustrates the preparation of an enzyme thinned ethylated cornstarch using a jet cooker according to the teachings of the present invention.
• a low degree of substitution of about 0.038 (1.0%> by wt. ethylene oxide substitution based on ds starch) ethylated cornstarch was thinned through a jet cooker with a high temperature alpha amylase.
• 974 lbs. ds (dry substance) basis ethylated cornstarch (Penford Gum 200, Penford Products Co., Cedar Rapids, IA) was slurried in water to a Be' Tc of 19.2 which is equivalent to about 34.1 % solids ds basis.
• the temperature of the slurry was about 100°F and the pH was about 6.4.
• To this slurry was added 164g CaCl 2 -2 H 2 O (100 ppm Ca ++ ) and 141.4 g (0.032% by wt. based on ds starch) alpha amylase (Spezyme AA-L Heat Stable Alpha-Amylase, Genencor International) with an activity of 5650 TAU/g.
• One TAU is defined as the quantity of enzyme that will dextrinize one milligram of starch per minute a pH 6.6 and 30°C under specific assay conditions.
• a fixed displacement pump was used to pump the slurry through a jet cooker at a rate of 4.3 gal./min.
• EXAMPLE 8 This example illustrates the preparation of an enzyme thinned ethylated cornstarch using a jet cooker according to the teachings of the present invention.
• a low degree of substitution 0.038 (1.0% by wt. ethylene oxide substitution based ds starch)
• ethylated cornstarch was thinned through a jet cooker at between 190 and 200 °F with a low temperature alpha amylase. Specifically, 776 lbs.
• ds (dry substance) basis ethylated cornstarch (Penford Gum 200, Penford Products Co., Cedar Rapids, IA) was slurried in water to a Be' Tc of 19.2 which is equivalent to about 34.1%o solids ds basis.
• the temperature of the slurry was about 93 °F and the pH was about 6.7.
• To this slurry was added 131 g CaCl 2 -2 H 2 O (100 ppm Ca ++ based on ds starch) and 70.4 g (0.02 % by wt. based on ds starch) alpha amylase (Validase BAA 1200L, Valley Research) with an activity of 1,320,000 mwu/gram.
• a fixed displacement pump was used to pump the slurry through a jet cooker (hydro-thermal series M104MSX manual stainless hydroheater, hydro-thermal corporation, Milwaukee, WI 53213) at a rate of 3.6 gal./min. at 194-197°F cooked paste temperature measured in line just after the cooked paste had passed through the jet cooker.
• the starch paste was cooked into a 75 gallon, V-bottom hold tank (approx. dimensions of 12" radius by 36" height with a 3" cone on the bottom) and held without agitation for 20 minutes, 16 minutes and 18 minutes at a temperature in the hold tank of about 178°F. Because the tank was not agitated, the paste collected evenly from top to bottom (plugged flow).

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• 1999
  • 1999-08-31 WO PCT/US1999/019750 patent/WO2000012746A1/en not_active Application Discontinuation
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