NL8102091A - DILUTED STARCH DERIVATIVES. - Google Patents

Description

** »- * ** · * ^ $ · * =“ ΫΟΤ893. 1 Diluted starch derivatives.

This invention relates to dilute starch-derived vessels which provide graft copolymers with good tensile strength and abrasion resistance after vinyl polymerization with polymer monomers. In addition, after graft copolymerization with vinyl monomers, these starches have the unique property of form aqueous dispersions that are stable and do not exhibit a significant change in viscosity after prolonged periods of time even when the dispersions contain a high solids content, i.e., of the graft copolymer.

The preparation of starch derivatives and dilute starch types is known, as is its use for the preparation of aqueous dispersions after graft polymerization with vinyl monomers. It is also known that the polymeric dispersions obtained are suitable for paper coating as adhesives and sizing agents for hydrophobic fibers.

US Patent 2,922,768 discloses the use of an honorium (IV) salt along with polymeric alcohols which can be oxidized by the cerium salt to form graft copolymer and; starch, starch partial ethers such as cyanoethylated starch and starch partial esters such as acetylated starch are included in the disclosed polymeric alcohols. Brockvay, (J. Polymer et al: Vol. 20 A, vol. 2, pp. 3721, 1961), describes the use of hypochlorite oxidized starches. United States Patent 3,095,391 describes the use of granular, non-pasty starchy materials, such as native starch and modified starch, to form graft copolymers. The modified granular non-pasty starches described in this U.S. Pat. No. 3,095,391 include: oxidized granular starch, acid modified granular starch prepared by heating an acidified aqueous suspension below the pasting temperature, hydroxyethyl ethers of starch, and granular starch modified by reaction with aqueous vinyl acetate.

U.S. Patent 3,061,171 discloses the use of a "thin boiling starch" to avoid inadmissibly viscous emulsions (dispersions) of graft copolymers. A "thin boiling starch" (col. 2) is described as "those starch products, either -------- 81 02 0 9 1 ---------- --------- -------- - »! —T- '----': '' ~> ο _ 2 modifications of native starch or derivatives which, after gelatinized in water, form pastes that are less viscous, are adhesive and tough and lead to less gel formation than the native starches.

. Such modified starches and starch derivatives include, for example, hypochlorite-oxidized, acid-modified; ethers (eg hydroxyethyl and carboxymethyl ethers), acetates,! the enzymes reacted with enzymes, etc. The use of a number of vinyl monomers with modified 1; • I refined and unmodified starches, both granular and 10, gelatinised (pasty) as starting materials for the preparation of starch graft copolymer and is known. US Pat. 3 * 0él bJ2 describes thin-boiling starches such as hypochlorite oxidized and acid modified starches, starch ethers, starch acetates and enzyme-converted starches polymerized with an acrylic acid ester of an alkanol. The products are suitable for dressing hydrophobic fibers. U.S. Pat. No. 3,095,391 describes the use of granular non-pasty starch, granular hypochlorite oxidized starch, acid modified granular starch prepared by heating an acidified aqueous suspension of granular starch below the pasting temperature, granular starch reacted with ethylene oxide, and granular starch reacted with vinyl acetate, as suitable materials for polymerization with vinyl monomers including vinyl acetate, ethyl acrylate, styrene, methacrylic acid, the butyl esters of acrylic acid and methacrylic acid, methyl methacrylate, acrylonitrile, acrylamide, ^ -vinylpyridine and diethylamino-methyl methacrylate. The products are suitable as adhesives, flocculants and sizing agents.

The graft copolymerization reactions are usually carried out in aqueous media, the resulting compositions being aqueous dispersions or latices. Since the valuable and useful portion of such a latex is the graft copolymer portion of the dispersion, it is desirable that the compositions be prepared at the highest solids content possible. Furthermore, if the latices are to have a suitable lifetime, they must be stable. That is, the dispersions must not separate into two or more phases within the time period required for commercial application or an excessive increase in the ~ 8 OTT ........

3 viscosity. Such problems in the preparation of polymer compositions from known starches are disclosed in U.S. Patent 3,984,361, according to which gelatinized cationic starches polymerized with a vinyl monomer to form aqueous dispersions are stabilized by sound vibration. U.S. Patent 4,029-616, according to which aqueous dispersion. Polymerized pullulene with a ethylene compound are distinguished from those based on starch in that they are stable and do not undergo gelling or "aging".

10 - The preparation of graft copolymers of starch and vinyl monomers initiated by inducing free radicals on a starch is known. Overviews are published by J.C. Arthur, Jr. (Advances in Macromolecular Chemistry, vol. 2. Academie Press, London & Jeff Lork, pp. 1-87, 1970) and by G.F. Fanta (Block and Graft Copolymers vol. 1 15 John Wiley & Sons, London & Hew York, pp. 1-45, 1973).

A number of chemical activators are known. U.S. Patent 3,138,564 describes graft polymerization of 1,3-butadiene and acrylonitrile on starch using ozone and Fe (11).

British Patent 869,501 describes the preparation of graft polymers of starch using polymerization initiators such as hydrogen peroxide, organic peroxides, hydroperoxides and dilute cerium (IV) ion solutions. Yields can be improved by using an activator for these initiators, such as mild reducing agents, for example, ferro-ammonium sulfate, sodium formide hydrosulfoxylate and the like.

C.E. Brockway (Am. Chem. Soc. Div. Org. Coatings Plast.

Chem. pp. 502 - 508, 1967) and U.S. Patent Nos. 3,061,471 and 3,061,472 describe the use of hydrogen peroxide to graft polymerize various monomers on starch. In addition, 30 C.E. Brockway (J. Polymer Sci. Part A, Vol. 2, pp. 3721-3731, 1964) using hydrogen peroxide for the graft polymerization of methyl methacrylate on starch. For the most part, these initiators are non-specific and induce homopolymerization of single monomers and copolymerization of monomer mixtures, as well as the desired graft polymerization of the monomer and monomer mixtures on the starch. This results in products that tend to curdle on storage.

8102091 .......

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Such problems can be minimized or avoided by using a Cerium (IY) initiator. Although with application; from Cerium (lT) by Fanta et al (J. Appl. Polymer Sci. vol. 10, p.

. 919 - 937 »1966) some bomb polymerization is mentioned may be expected.

1 5 · that the key method of the Cerium (lV) introduction of free; : radians as listed by Fanta (Block & Graft Copolymers, vol. 1 * biz.

; 3 · Ed. · R. J. Ceresa, John Wiley & Sons, London & Hew York, 1973) graft; copolymers to the exclusion of all homo- or copolymers. From ! this system has been extensively used to graft vinyl monomers on starch.

The starches of the invention are dilute derivatives. The starches have been derivatized to a degree of substitution of about 0.05-0 and diluted to an intrinsic viscosity of about 0.12-0.28 dl per g (dl / g). The invention also includes "methods of preparing the dilute starch derivatives.

These dilute starch derivatives and, after polymerization with a vinyl monomer or monomers under the influence of a free radical initiator, which actively promote the formation of graft copolymers, virtually exclude the formation of homo or copolymers of the vinyl monomer. or the vinyl monomers, dispersions that do not exhibit phase separation problems, impermissible viscosity increases after storage and gelation inherent in the dispersions formed from known starches. In addition, these starches provide graft copolymers of starch with good tensile strength and wear resistance.

The dilute starch derivative and according to the invention are suitable starting materials for the preparation of starch graft copolymers with good tensile strength and wear resistance. In addition, due to the physical and chemical properties of the dilute starch derivatives, stable dispersions with a high solids content, ie, greater than 25% solids, can be prepared. These dispersions are stable for a long time (and do not show an inadmissible increase in viscosity or gelation). They are suitable as sizing agents for textile fibers and as coatings and adhesives for paper products. Moreover, these new dilute starch derivatives are suitable for the usual applications of such starches, for example as industrial adhesives and adhesives for corrugated sheets. Let 81 0 2 0 9 1. “~~~ ...........................

5

Also can be used as thickeners for paint materials and the like.

The new starches according to the invention are derivatives in a dilute state. For optimal results for the preparation of the stable, aqueous starch graft copolymer dispersions which pass through. these starches are supplied, the latter should be free from substances that interfere with the graft polymerization reaction or adversely affect the final dispersion. In the derivative preparation step, reagents, salts or by-products that exhibit such effects can be introduced. Such substances can be easily removed by washing the starch derivative provided that the starch retains its granular form. A small degree of solubility can be tolerated in the granular starch since it is easily suppressed by adding a water-miscible organic liquid, such as ethyl alcohol, to the wash water.

The starch can be diluted by chemical methods, such as by acid hydrolysis followed by derivatization, maintaining the starch in granular form. Similarly, derivatives of the starch may first be formed and the granular product may then be gelatinized and diluted. A combination of acid and enzyme dilution is also possible. When the preparation of derivatives is the first step, it is preferred that the dilution be carried out by enzymatic means. This order is the preferred method of preparation of the starches.

The starches useful for the preparation of the dilute starch derivatives of the invention are those such as corn starch, wheat starch, potato starch and the like. Corn starch is preferred.

The preparation of starch derivatives is known. However, it has been found that in order to form starch derivatives having properties which give stable dispersions after graft polymerization with vinyl monomers, it is necessary to control the degree of substitution. The substituent type also has an effect on the stability of the dispersions. It is also necessary to control the degree of dilution of the starches if optimum physical properties such as tensile strength and abrasion resistance of the polymers are desired to be achieved.

'81 0 2 0 9 1 6 ^ V ____ _ __ ^

At the same degree of substitution, bulky and charged substituents on the starch tend to generate relatively more stable dispersions than small or uncharged substituents. All substituents that do not interfere with the polymerization and which provide starch derivatives with a stable viscosity at a solid content of one; about 30 - h5 wt. # after dilution are suitable. These include anionic, cationic and nonionic substituents. Preferred substituents are of the cationic and nonionic type. Carbamylethyl, alkyl, benzyl and benzalkyl starch derivatives are examples of the 10Q nonionic derivatives. The dialkylaminoalkyl substituents are an example of cationic derivatives.

The preferred starch derivatives are those with hydroxyl, cyanooxyl, dialkylaminoethyl and acyl substituents. Most preferred are the hydroxyethyl, cyanoethyl, diethylaminoethyl, carbamylethyl-15 and acetyl derivatives.

, v

The degree of substitution chosen will influence the degree of change in the viscosity of the dispersion formed by graft polymerization. At a higher degree of substitution, dispersions can be prepared whose viscosity does not double in 30 months. At 20 .. most industrial applications, such are extremely stable. latices not required. Practical considerations are that the final dispersions before being processed must not become so viscous that they are difficult to handle or have to be diluted to a solid content that is too low for the intended use. The final viscosity of the polymeric dispersions will depend on the initial viscosity:. starch dispersion and this viscosity is related to the solid content of the starch dispersion. An increasing solid content increases the initial viscosity of the polymer dispersion. Accordingly, if a low solids content in the intended use is sufficient, the polymeric dispersion can be prepared with a low solids content and thus a low initial viscosity, allowing a greater increase in viscosity without the mixture becomes impermissibly viscous.

The degree of substitution of a starch derivative is not directly proportional to the properties that impart an improved viscosity stability to the polymer dispersions. At one. low substitu- - - - Λ Λ 4 '* r.

There is little effect on the stability of the viscosity of the dispersion obtained by graft polymerization of the starch derivatives with vinyl monomers, depending on the type of substituent, but there is a dramatic, unexpected improvement in the stability of final starch graft copolymer latex product to occur at a degree of substitution of the starch of about 0.05 - 0.1, as illustrated in Figure 1. With a bulky and / or charged substituent, such as the diethylaminoethyl group, stability is achieved by a degree of substitution rapidly increased above about 0.05 With the carbaiqylethyl-10 group, a similar increase is observed at a degree of substitution above about 0.1 At a degree of substitution between 0.08 and 0.09, the cyanoethyl and acetyl derivatives show the same marked improvement of the stability of the final dispersion.

The starch derivatives of the invention have a degree of substitution of at least about 0.05. The maximum degree of substitution is limited only by practical considerations. For the polymerization, it is desirable that the starch derivative be free from reverse. put reagents, salts and by-products. This can be done most economically by washing the derivative, which is facilitated if the starch retains its granular form and is not dissolved by excessive derivative formation. Since a higher degree of substitution usually leads to an increased solubility of the derivatives, the degree of substitution must be chosen according to the removal of the reagents, salts and by-products.

The preferred range of the degree of substitution is about 0.05-0.1, particularly preferably about 0.06-0.2.

The starch derivatives suitable for use according to the invention are those which can be gelatinized and diluted.

The formation of colored products can be prevented by avoiding extremely high temperatures during these processes. Dilution can be done by known methods, such as by acid hydrolysis or enzyme treatment. Dilution by enzymatic agents, such as alpha amylase, is preferred.

The degree of dilution of the starch, as determined by the intrinsic viscosity, is an important aspect of the invention. Excessive dilution will adversely affect the properties of the starch, which ...... 8102091: 8 ke to the copolymers obtained from the starch, give optimum tensile strength and wear resistance. For example, by: free films, of a graft copolymer prepared from a cyanoethyl starch with a substitution degree of 0.161, is diluted to an intrinsic viscosity 5. (dl / g) of about 0.10, 0.1k, 0.18, and 0.27, and polymerized with; ethyl acrylate, shown that relatively small changes in intrindic viscosity can have a significant effect on the physical properties of the graft copolymer. A free movie cast from! the copolymer obtained from the starch, diluted to an intrinsic viscosity of about 0.10 dl / g, had a tensile strength of about 170 g / mm. However, when the same starch was diluted to an intrinsic viscosity of about 0.1U dl / g, a film of a copolymer prepared from this starch was found to have a tensile strength greater than 2000 g / mm. The tensile strength did not show a significant increase above this value as the intrinsic viscosity increased, but slowly decreased to about 1,950 g / mm at an intrinsic viscosity of about 0.18 g and to about 1,870 g / mm at an intrinsic viscosity of about 0.27 dl / g.

Similar changes in abrasion resistance were seen when the copolymers were applied to a 50% O% cotton-polyester blending yarn and the cycles up to 11 breaks were measured on a Walker (T.M.) Abrader. With the copolymer prepared from the starch diluted to an intrinsic viscosity of about 0.10, 171 fractions required only about 820 cycles. However, when the copolymer was prepared from the starch diluted to about 0.14 dl / g, the number of cycles required for 11 fractions rose above 1,100. The number of cycles for 11 fractions remained above 1,100 upon dilution of the starch to an intrinsic viscosity of about 0.18 and used for a copolymer, and decreased to about 1,000 upon dilution of the starch to an intrinsic viscosity of about 0.27 used for a copolymer.

The intrinsic viscosity range of the dilute starches is about 0.12 - 0.28 dl / g. For optimal tensile strength properties of the graft copolymers, a range of intrinsic viscosity of about 0.13 - 0.21 dl / g is preferred.

35 All monomers which can be converted to the diluted starch derivatives by a free-radical initiated reaction ....... "" "eTöYöTf .......

Polymerized can be used to prepare starch graft copolymers. Generally, vinyl monomers such as vinyl halides, vinyl esters, vinyl ethers, alkyl vinyl ketones, H-vinyl carbazole, H-vinyl pyrrolidone, vinyl puridene, styrene, alkyl styrenes, acrylic acid, alkyl etherylates, methacrylic acid, alkyl methaerylates, acrylamide, substituted acrylamide, acrylamide, substituted acrylamide. 1-3-butadiene and the like are suitable. Of these, acrylonitrile, methyl metacrylate, vinyl acetate, 2-ethylhexyl acrylate and the lower alkyl acrylates, such as methyl acrylate, ethyl acrylate and butyl acrylate, are preferred when a single monomer is used to form the graft copolymer.

The particularly preferred monomers used to prepare the graft copolymer and starch are methyl acrylate, ethyl acrylate and methyl methacrylate.

As is known, combinations of two or more monomers can be polymerized together to form copolymers or block copolymers, and such combinations can also be used to prepare starch graft copolymers with the dilute starch derivatives. When two or more monomers are polymerized with the starches, the preferred monomers are dimethylaminoethyl methacrylate, ethyl acrylate, butyl acrylate, methyl methacrylate and methacrylic acid.

Any polymerization initiators which actively initiate free-radical polymerization on the dilute starch derivatives with the near inclusion of the initiation of homo- or copolymerization of the monomer or mixture of monomers used to form a starch graft copolymer can be used considered as suitable introductors.

Cerium (17) ammonium nitrate is an example of such an initiator. This initiator can be used in an amount of about 0.5-8% by weight of the dilute starch derivative. Amounts below about 0.5% do not adequately initiate graft polymerization and easily yield substantial amounts of unreacted monomer. Introductory levels of about 1, h - k% by weight of starch are preferred.

The combination of hydrogen peroxide and acetate ions is also a suitable initiator. Hatrium acetate or glacial acetic acid can be used to provide the acetate ion. This initiator can be used at a pH in the range of from about 2 to 9 and at an introduction of 8102091 ~ .....; · · .Ία.

th temperature of about UO - 90 ° C. The mole ratio of acetic acid to hydrogen peroxide is about 2, and the amount of peroxide is about 0.5 - 2.0%, based on the weight of the starch.

The amounts of monomer or monomers to be added y. will depend on the properties contained in the final dispersion; wishes'. Dispersions made from dilute starch derivatives can have a solids content of. to as high as 50 wt.% or more, on a dry basis. The starch-monomer ratio may be 100/25 by weight or less on a dry basis. and is preferably 100 Ao or less. The lower limit Iff of this ratio is chosen depending on economic considerations and the intended viscosity of the final dispersion. As increasing amounts of monomer are incorporated into the dispersions, the economic benefits of. the use of dilute starch derivatives as a significant portion of the final polymer less.

.15 The initial polymerization conditions should provide sufficient monomer to support the polymerization once initiated. This is easily accomplished in a conventional batch-mode mixing mode, where it. monomer or the monomers are added all at once. Any addition method, which effectively utilizes the 20 free radicals initially formed, without causing temperature control problems, will suffice, ie the monomer or monomers can be dispersed as a single component during the polymerization time or continuously. , being added,. as long as the required polymerization conditions are achieved. When mixtures of monomers are used, they are added as such to prepare the conventional type of copolymer chain grafted onto the starch or they may be added sequentially, individually or as separate mixtures to form block copolymers grafted onto the starch.

The temperature at which the polymerization is carried out will depend on the. used monomer system and the catalyst.

Heating or cooling or a combination thereof may be necessary to achieve or maintain the desired polymerization temperature. Temperatures. can be used in the range 0-100 ° C, depending on the catalyst and the monomer system. Temperatures in the range of 25-80 ° C are preferred. However, if a catalyst forms or needs a lower pH 8102091 11, a. prolonged contact under such an acidic condition will result in excessive hydrolysis of the starch, thereby adversely affecting the properties of the final polymer.

Surfactants can be used to stabilize the dispersions during the polymerization or they can be added after the reaction is complete. When present during the polymerization, the selected surfactant should not interfere with the initiator system or otherwise adversely affect the polymerization reaction. Triton X-200 and Triton X-h05 (Hohm & Haas Co.) are examples of surfactants that do not interfere with the polymerization reaction when the initiator is a cerium compound.

The following examples are illustrative of the invention and are not intended to be limiting.

Unless otherwise indicated, the terms "solid" and "percentage solid" as used herein mean total dry. substance including starch and, if applicable, any monomers used to form the graft copolymer dispersion of starch. Viscosities, expressed in centipoises (eps), are determined at 2h ° C, unless otherwise indicated, using a model. H.A.T. Brookfield viscometer and the appropriate spindle. The applied expressions and procedures are now explained in more detail.

Activity of soluble alpha-amylase The activity of soluble alpha-amylase preparations was determined by a modification of the standard test method AATCC 103, 1965 "Bacterial Alpha Amylase Enzymes Used in Desizing, Assay of" published in the 1967 edition of the Technical Manual of the American Association of Textile Chemists and Colorists, volume ^ 3, p. B-17 ^ 30 and B-175. The method was modified as follows:

The buffer solution for the starch substrate was prepared by adding 25.3 g c.p. sodium hydroxide and 3 ^ 0 g c.p. dissolve potassium dihydrogen phosphate in water and dilute the solution to 2 L; 125 ml of the buffer solution was added to the cooled paste-formed starch-substrate before the substrate was brought to a volume of 500 ml; the pH of the starch substrate was determined and adjusted to 8i 0 2 0 9 1 * 'Nr - · ... · '12 ¢, 20 + 0.05 if necessary; and "a Q, Q25 molar calcium chloride solution," prepared by dissolving 13.1 g of anhydrous c.p. calcium chloride in water and bringing the volume to "1" was used by enzyme sample dilutions.

The results were converted to liquefons where one bacterial amylase-5 unit is equal to. 2.85 liquefons.

Intrinsic Viscosity The intrinsic viscosity measurements were performed on a number of 32% starch pastes that had been pre-liquefied and diluted to a Brookfield viscosity ranging from 0 to 30,000 cps.

IQ Measurements of the reduced viscosity were first obtained at 5 dilutions (Q, 5 g / 100 ml, 1.0 g / 100 ml, 1.5 g / 100 ml *, 2.0 g / 100 ml • y and 2 * 5 g / lQQmlI of each sample according to the procedures of Myers and Smith "Methods in Carbohydrate Chemistry, vol. IV, pp. 12¾ - 127, published by RL Whistler, Academic Press, New. York, 196". Physical viscosity values were then obtained by extrapolating the reduced viscosity values obtained at the five dilutions to the zero concentration.

The following formulas were used to calculate the reduced viscosity values. In these formulas t is the 20 flow time in the Cannon-Ubbelohde viscometer for pure solvent (1.00 M iTaOE solution), t the flow time in the Cannon-Ubbelohde viscometer for the diluted starch solution at 1.00. to NaOH and C the concentration of the dilute starch in g per 100 ml.

Specific viscosity = ^ ^ "b

O

7su 25 Reduced viscosity = ^ = -jp

Kjéldahlstikst or analysis

Kjeldahl analyzes for nitrogen were performed using the standard analytical method of. the "Com Refiners Association", no. B- ^ 8.

30 Carboxyl analysis

Analyzes on carboxyl groups were performed using. the analytical standard method of the "Com Refiners.. Association", no. C-22.

-------- 81 0 2 0 9 1 <»13

Acetyl analysis

The carboxyl groups were determined using the standard analytical method of the "Com Eefiners Association", no.

C-2.

5 Degree of substitution

The degree of substitution (subgr) was determined using. the following formulas: a) nitrogen-containing substituents „. 1W _ (162 $) {% nitrogen) U ^“ (100) (14) - (A) ($ nitrogen) 10'A = molecular weight of the nitrogen-containing group minus one.

Cyanoethyl, A = 53,

Carbamylethyl, A * T1,

Diethylaminoethyl A = 99, b) acetyl-containing substituents _ c, _ (162) ($ acetyl) 15 Subgr {% acetyl) c) carboxyl-containing substituents _ (162) (% carboxyl) wUbgr - (1003 (45) - (44) (5 carboxyl).

Example I

This example illustrates the effect of the degree of substitution of the starch on the stability of the viscosity of the cyanoethyl, acetyl, diethylaminoethyl, and carbamylethyl starch derivatives.

A. Preparation of cyanoethyl corn starch derivatives

To 10 1 corn starch suspension (4θ, 8τ wt.% Dry matter starch) was added 10% anhydriseh sodium sulfate {% based on the dry matter content of the starch) and 590 ml sodium hydroxide solution (a solution of sodium hydroxide and sodium chloride with 1.65 equivalent titratable sodium hydroxide solution per liter and a density of 27 ° Baume at 20 ° C). The alkalinity of the suspension (ml of 0.1 L HCl required to neutralize 30 ml of suspension) was 24.0. 1597 ml of the suspension (equivalent to 728 g of dry starch per bottle) was added to each of 6 bottles of 1.9 liter capacity. The bottles, 81 0 2 09 1>> - '1¾ • equipped with agitator stirrers and inlets, were placed in a hot water bath (in a cabinet) and maintained at 45 ° C.

The appropriate amount of acrylonitrile was added to each bottle, as shown in Table C. After a 16 hour reaction period, the mixtures were adjusted to a pH of 6.3, filtered and washed twice and dried at 82 ° C. Each sample was analyzed for Kjeldahl nitrogen and the nitrogen value (less than 0.04 $) the degree of substitution of the i ". cyanoethyl groups calculated.

i; * 4 = 1 4 = 2 4 = 3. Lïk L! J = £ TO Applied acrylonitrile {% based on dry 1.0 2.5 3.0 3.5 4.0 6.0 starch dust)

Nitrogen 0.259 0.535 0.674 0.709 0.844 1.324

Analysis {% N) 15 Calculated degree of substitution 0.030 0.0β9 "0.080 0.084 0.101 0.161

The cyanoethyl corn starch derivatives were diluted by enzymes and graft polymerized and the stability of the viscosity of the products obtained was determined.

B. Preparation of Acetyl Corn Starch Derivatives

The method of C.E. Smith and J.V. Tuschoff, U.S. Patent 3,081,296, was used using vinyl acetate in aqueous media to prepare corn acetate derivatives. starch with different degrees of substitution.

Dry corn starch powder (about 4369 g of dry basis) was added to water with stirring, yielding 9000 ml of a 23.0 ° Baumé starch suspension (40.8% dry matter). The pH of the mixture was adjusted to 7.0 and 1500 ml of the slurry was placed in each of 6 1.9 L bottles (equivalent to 728 g of dry starch each). The 1.9 L bottles, equipped with stirrers and reagent addition ports, were placed in a constant temperature water bath. At a bath temperature of 27 °, the appropriate amount of sodium carbonate was added, followed by an appropriate amount of vinyl acetate (see below). After a reaction period of 8102091 ~ 15 * 15 minutes, each suspension was adjusted to pH 6.4 with dilute hydrochloric acid. Each product slurry was filtered through paper, washed twice with further water and then dried in a forced air oven at about 82 ° C. The analyzes for the acetyl-5 content were obtained by standard methods to determine the degree of acetyl substitution for each product.

B-1 B-2 B-3 B-4 2-5 B-6, Amount of sodium carbonate (% based 0.63 1, ½ 1.92 2.64 3.33 4.29 10 on dry starch)

Amount of added vinyl acetate (% based on dry starch 2.10 4.80 6, ½ 8.80 11.11 14.3 flour) 15 Acetyl content {%) 0.83 1.77 2.66 3.26 3.88 4.85

Calculated degree of substitution 0.032 0.068 0.103 0.127 0.152 0.192

The starch acetate derivatives were then diluted by enzymes and graft polymerized and the viseosity stability of the obtained products was determined.

C. Preparation of diethylaminoethyl corn starch derivatives

To each of four 1.9 L bottles contained in a water bath and equipped with stirrers, 1500 ml of a suspension containing 728 g of corn starch powder was added. To each suspension, 158 g of sodium sulfate, the appropriate amount of diethylaminomethyl chloride reagent (see below) were added and the pH adjusted to about 7.0. The appropriate amount (see below) of sodium hydroxide brine (a solution containing 6.60 g of sodium hydroxide and 25.6 g of sodium chloride per 100 ml) was then added to each suspension. The reaction mixtures were stirred at 50-55 ° C for 7 hours, cooled and filtered through a Buchner funnel. Methanol was added in cases where filtration was hindered by swollen starch particles. The DEAE starch derivatives were washed twice with water or '......' 81 0 2 0 9 1 1 '' -Π'- · - 'Π π.,, - -Γ-, - · Π 1-Ι-— 7 γ ~ ·; ·. 16 wash a barrel / hand (35/65) solution and dry. The nitrogen contents (Kjeldahl method) were obtained to calculate the degree of derivatization.

C-1 C-2 C-3 C-4 "5 i suitable diethyl; 1 aminoethyl chloride 3 * 19 6.37 12.7 ^ 21.23. {% based on starch) - t

Ephatron lye salt solution Cml / 1500 ml brew (161+ 328 655 1091 ta flour suspension)

Nitrogen content {% dry basis) 0.299 0.1 + 37 0.5 ^ 9 1.01+

Calculated degree of substitution 0.035 0.052 0.066 0.130 The DEAE starch derivatives were diluted by an enzyme and graft polymerized and the viscosity stability of the products obtained was determined.

D. Preparation of carbamylethyl corn starch derivatives

Acrylamide was reacted with granular starch in an alkaline suspension using the method of E. F., Paschall, U.S. Patent 2,928,827. To 7500 ml of the corn starch suspension, which contained 3622 g of dry starch, was added 97 g of dry sodium sulfate and 815 ml of sodium hydroxide solution (a solution containing 6.60 g of sodium hydroxide and 25.6 g of sodium chloride per 100 ml). The alkaline suspension was divided into four equal parts and placed in 1.9 L bottles contained in a water bath and equipped with stirrers and thermometers. The appropriate amount (see below) of acrylamide was added to each bottle and the mixtures were allowed to react at 52 ° C for 18 hours. The resulting starch slurry was adjusted to a pH of 1.0 + and filtered using a Buchnert straight there. The filtered products were each washed twice with water, filtered and dried. The ------ obtained starch derivatives were run on nitrogen (Kjeldahl analysis) and 81 02 0 9 1 "

• IT

carboxyl content (carboxyl groups are formed by partial hydrolysis of carbamylethyl groups to form carboxyethyl groups} analyzed to calculate the degree of derivatization.

D-1 D-2 D-3 P-4 5 Applied acrylamide (% dry starch) 1.32 3.0T 3.95 7.89

Nitrogen analysis (% dry matter) 0.162 0.345 0.431 0.709

Carboxyl analysis (% dry basis) 0.11? 0.224 0.287 0.485 10 Calculated degree of substitution, carbamylethyl groups 0.019 0.04l 0.051 0.093

Calculated degree of substitution, carboxyethyl groups 0.004 0.008 0.010 0.018

Calculated total substitution degree 0.023 0.049 0.06L 0.111

These starch derivatives were diluted by enzymes and graft polymerized, after which the viscosity stability of the products obtained was determined.

E. Enzyme Dilution and Graft Polymerization The following procedure was used to prepare graft copolymers from each of the samples in A-D of this example.

650 g of deionized water, then 350 g of dry base starch derivative, were introduced into a 2 l resin kettle equipped with a stirrer, thermometer, a reflux condenser and nitrogen gas dispersion tube, after which a 35% starch suspension was obtained. The pH was adjusted to 7.5 -

7.8 adjusted followed by addition of 4350 liter fons alpha-amylase activity obtained from B. subtilis. The slurry was heated at 78 ° C for a period of 45 minutes and held at that value until the gelatinized starch viscosity was about 200 cps (24 C 30 Brookfield No. 2 spindle, 20 ppm). The enzyme was inactivated by heating to 96 ° C and the liquefied starch to about 60 ° C

8102091 1 'T- ----- Lift -' '' · ™ '~~' "......

i I 18 [.

i: 'intended. At a temperature no higher than 60 ° C, "nitrogen blowing" was started and 12.5 g of Triton X-200 surfactant was added, followed by addition of 178.5: g of ethyl acrylate. At a temperature of k8 - 52 ° C, 6.13 g of cerium (IY) ammonium nitrate dissolved in 15 g of deionized water was added. After the exothermic reaction had subsided (temperature increase about 20 ° C), the reaction was stopped ; temperature maintained at 75 ° C for 3 hours. Then 0.5 g of each of ammonium persulfate and sodium metabisulfite was added to the reaction mixture. is added to reduce the amount of unreacted monomer. The τα mixture was kept at 75 ° C for an additional hour, cooled to room temperature and adjusted to pH 8.5 with 28% ammonium hydroxide. The. final preparations and had a solids content of about ^ 5.0 $.

In Table A, the data obtained on the stability of the viscosity of the samples are summarized. ·> ·

"TABLE A

15 days to 100 $ increase in viscosity

Substituent: DEAE H Acetyl Cyanoethyl Carbamylethyl

Sub.gr.

0.023 ~ 1-2 0.030 <1 20 0.032 2-3 0.035 <1 0.019 1-2 0.052 1-2 0.061 5-6 25 0.066 »60 0.068 15-16 0.069 7-8 0.081 16-17 0.101> 60 30 0.103> 60 0.111 57-58 0.130 3Si 0.152 ** 0.161 35 0.192 sas 8102091 - '' "- ~ '- - ~' 11 11 - ^ - - | · '-'IJ - 19

Note to Table A * diethylaminoethyl

ss no significant change in viscosity after 60 days. Example II

This example shows the relationship between the intrinsic viscosity of the dilute starches and the tensile strength and abrasion resistance of graft copolymers prepared from the dilute starch.

Four samples of an eyanoethyl-substituted corn starch prepared according to Example I, A-6 (degree of substitution 0.161) were obtained. according to the procedure of Example I, E diluted by enzymes to different viscosities. Each of these samples was graft polymerized according to the procedure of I, E.

Free films of the graft copolymers were cast on Mylar (T.M). The films were dried, cut into 11 inch wide strips, and then stored at 65% relative humidity and 21 ° C for about 5 days. The average thickness of the films was determined and the tensile strength measured with an Ihstron-ΊΜ universal measuring instrument. The tensile strength relationship with each of the intrinsic viscosities of the dilute starch derivatives is shown in Table B.

The four graft copolymers were applied as a sizing agent on a 50% cotton / 50% polyester yarn and conditioned at 65% relative humidity and 21 ° C for about 2 days. The abrasion resistance of these samples was then determined with a Walker Abrader according to the method of Stallings and Worth, "Textile Industries", March 25, 195. This method consists of sanding 36 sets of yarn and reporting the number of cycles to obtain the first 11 breaks. The results are reported in Table B.

TABLE B

Intrinsic viscosity Tensile strength Abrasion resistance (number of dl / g_ g / mm ^ cycles up to 11th break) 30 0.1 1U70 825 o, iU 2030 1150 0.185 1950 1120 0.273 1870 1020

2 09T

Claims (8)

Diluted starch derivative according to claims 1-2, characterized in that the intrinsic viscosity is about 0.13 - 0.21. 10 k. Diluted starch derivative according to claims 1-3 », characterized in that the substituent is a non-ionic substituent. Diluted starch derivative according to claims 1-3, characterized in that the substituent is a cationic substituent. Diluted starch derivative according to claims 1-3, characterized in that the substituent is selected from hydroxyethyl, cyanoethyl, diethylaminoethyl, carbamylethyl and acetyl. J. Process for preparing a dilute starch derivative capable of yielding stable, high solids aqueous dispersions upon graft copolymerization with a vinyl monomer, characterized in that a starch derivative having a degree of substitution of about 0.05-0 , k, is prepared, which starch is diluted to an intrinsic viscosity of about 0.12 - 0.28 dl / g, while maintaining the granular form of the starch after the derivative forming step. Method according to claim 7, characterized in that the degree of substitution is about 0.6 - 0.2. 9. Process according to claims 7-8, characterized in that the starch is diluted to an intrinsic viscosity of about 0.13 - 0.21. 10. A method according to claims 7-9, characterized in that the starch derivative is first prepared and then diluted with enzymatic agents. A method according to claim 10, characterized in that the substituent is a non-ionic substituent. ---------- 84-0-2-444 - -----------—............- - <ΐ. t2. Process according to claim 10, characterized in that the substituent is a cationic substituent. 13. A method according to claim 10, characterized in that the substituent is selected from acetyl, hydroxyethyl, eyanoethyl, carbamylethyl and diethylaminoethyl. . 1¾ .. Industrial adhesive prepared from a dilute starch derivative according to any one of claims 1-6. - 8102091 —---