AU628975B2 - Special amyloses and their use in the production of biologically degradable plastics - Google Patents

Abstract

The invention relates to special amyloses for the production of biodegradable, clear, transparent and flexible plastics, especially foils and films, which: (a) swell but do not dissolve in cold water, (b) produce uniform fluid quasi-solutions without gel formation on heating to above 80 DEG C with agitation, where this state is maintained on cooling to a temperature of 50 DEG C without gel formation and deterioration for at least five minutes and the solution, in a concentration of 5 to 25% can be extruded on a flat substrate with a slot width of 100 to 700 mu m.

Description

DPI DATE 29/11/90

P

INTER: ADJP DATE 10/01/91

INTER

APPLN. JD 55255 PCT NUMB3ER PCTF/EP9O/00675 R DIE

(PCT)

(51) Internatiunale Patentklassifikation 5 Internationale Veroffentlichtingsnummer: WO 90/13576 C08B 33/00, C08L 3/14 Al (43) Internationales CO8J 5/18 Verbffentlichungsdatum: 15. November 1990 (15.11.90) (21) Internationales Aktenzeichen: PCT/EP9O/00675 (74) Anwalt: RA BEN I-ORST, Helmut; Am R~5merhiof 35, D- 6000 Frankfurt am Main 90 (DE).

(22) Internationales Anmeldedatum: 26, April 1990 (26.04.90) (81) Bestimniungsstaaten: AT (europ~isches Patent), AU, BE Priori tiitsdaten: (europfiisches Patent), CA, CH (europ~isches Patent), P 39 14 350.3 29. April 1989 (29.04.89) DE DE (europ~isches Patent), DK (europiiisches Patent), ES (europ~isches Patent), FR (europ~isches Patent), GB (europtiisches Patent), IT (europaisches Patent), JP, KR, (71) Anmelder Utir alle Bestimnmungssraaten ausser US). BAT- LU (europiiisches Pat-it), NL (europ~isches Patent), SE TELLE-INSTITUT E.V. [DE/DE]; Am Romerhof 35, (europ~isches Patent), US.

D-6000 Frankfurt am Main 90 (DE).

(72) Erfinder; und Veroffentlicht Erfinder/Anmelder (nur~fidr US) :FRISCHE, Rainer [DE/ Mit internationalein RecIherclienbericir.

DE]; Schflttenhelmweg 60, D-6000 Frankfurt am Main WOLLMANN, Klaus [DE/DE]; Bahnhofstrale 33, D-6250 Limburg 7 GROSS-LANNERT, Renate [DE/DE]; Talstralle 11, D-6057 Dietzenbach (DE).

SCHNEIDER, Judith [DE/DE]; ThOringerweg 61, D- 6238 Hofheim BEST, Bernd [DE/DE]; Annastra- R~e 13, D-6082 M6rfelden (DE).

28975 (54)Title: SPECIAL AMYLOSES AND THEIR USE IN THE PRODUCTION OF BIOLOGICALLY DEGRADABLE PLA-

STICS

(54)Bezeichnung: SPEZIALAMYLOSEN UND IHRE VERWENDUNG ZUR HERSTELLUNG BIOLOGISCH ABBAU- BARER KUNSTSTOFFE (57) Abstract The invention relatts to special amyloses for the production of biodegradable, clear, transparent and flexible plastics, especially foils and films, which: swell but do not dissolve in cold water, produce uniform fluid quasi-solutions without gel formation on heating to above 80*C with agitation, where this state is maintained on cooling to a temperature of 50*C without gel formation and deterioratiorn for at least five minutes and the solution, in a concentration of 5 to 25%/ can be extruded on a flat substrate with a slot width of 100 to 700 1tm.

(57) Zusammenfassung Die Erfindung betrifft Spezialamylosen zur Herstellung von biologisch abbaubaren, klaren, transparenten und flexiblen Kunststoffen, insbesondere Folien und Filmen, die dadurch gekennzeichnet sind, dag sie: in kaltem Wasser quellbar aber nicht li6slich sind; beim Erhitzen unter Rahren oberhalb 80'C unter Atmosph Arend ru ck ohne Bildung von Gelen homogene fliegf~hige Quasilbsungen ergeben, wobei dieser Zustand beim Abk~hlen auf eine Temperatur von 50'C ohne Gelbildung und Retrogradation mindestens 5 Minuten erhalten bleibt und die L6sung in einer Konzentration von 5 25% auf einer planen Unterlage bei einer Spaltbreite von 100 700 4im rakelfithig ist.

Siehe Rtickseite -7-7 396-17/UMA December 6, 1990 Special Amyloses and Their Use for Producing Biodegradable Plastics The present invention relates to special amyloses and their use for producing biodegradable, clear, transparent and flexible plastics.

Using native raw materials and processing them into technical products has hitherto been of only minor importance, although such raw materials are available in sufficient quantities and at acceptable prices. In particular if aspects of environmental policy are taken into account, however, it is to be expected that these renewable raw materials will gain increasing importance in the future.

A raw material which is particularly interesting in this respect is starch, which is available in sufficient quantity and can be obtained from a wide variety of sources. Starch consists of the two components amylose and amylopectin. These components are polymers composed of glucose units, with chain lengths and molecular weights extending over a wide range. Whereas amylopectin has a branched-chain molecular structure, amylose is a long unbranched-chain molecule. Therefore starch, not least because of its structure, presents ideal properties as a raw material for technical products.

The film-forming properties of amylose have long been known. An essential disadvantage of these films produced from amylose consists in their brittleness and low elasticity. Accordingly, the conventional amylose films are not very stable, which has the negative effect of low crease resistance and tensile strength.

Further disadvantages are their insufficient transparency, their rough surfaces and the sophisticated processes and equipment that are required for producing such films.

Attempts made to avoid these disadvantages by adding plasticizers, e.g. glycerol, sorbitol or, as described in DE-PS 17 45 680, polyvinyl alcohol, however, did not improve the product properties so far that these methods could have achieved greater technical mportance. The method of DE-PS 17 45 680 also requires that the -1 2 hot amylose solution is placed on a heated substrate or pressed through a nozzle into a coagulating bath which contains an acid or salts for precipitating the amylose film.

Other methods of producing plastics describe the use of chemically modified amyloses. Thus, GB-PS 965 349 and US-PS 3 117 014 describe compositions which contain hydroxyalkyl amyloses or other derivatized amyloses and which are suited for thermoplastic processing. Let alone that these compositions are intended exclusively for producing thermoplastic films, the film properties with respect to transparency and ease of handling achieved with these mixtures cannot in the least be regarded as ideal. This is why these plastics so far have not been used for technical applications.

The object of the present invention therefore was to provide amyloses which enable, in a simple manner, production of clear, transparent and flexible plastics and molded parts with improved properties, in particular sheets and films; these are to be characterized mainly by easy biodegradability, so that their disposal by composting will no longer involve major difficulties and problems.

According to the invention, it was found that the use of specific amyloses, both in the production of films and sheets by a simplified casting process and in the production of thermoplastic molded parts, leads to products with extraordinary properties compared with prior art, i.e. properties which cannot be achieved in the same manner if conventional amyloses are used.

The object of the present invention therefore are special amyloses as described in Claim 1. Another object is a simplified casting process for producing films and sheets on the basis of these special amyloses.

;LIv The special amyloses according to the invention are complex 0 -~1 3 mixtures of different chemical substances, preferably polymeric glycoses such as amylose and amylopectin, which show a behavior extraordinary for starches and amyloses. These special amyloses, which are natural polymers with statistical chain length distribution and a wide range of molecular weights, naturally are not accessible to accurate determination of the analytical structure; in the following, special amyloses are therefore understood as those fractions of amylose and amylose derivatives which are characterized by the following behavior: a) They are swellable in cold water, but not soluble; b) If heated with stirring above 80'C at atmospheric pressure, they yield homogenous flowable quasi-solutions typical of starch, i.e. they do not form gels which are inhomogenous with respect to flowability. If the solution is cooled to a temperature of 50'C, this state is maintained for a period of at least five minutes, without retrogradation. In a concentration of 5 to 25 weight such a solution is applicable to knife coating onto a plane surface with a gap width between 100 and 700 pm.

The special amyloses according to the invention can be obtained in different manners and from different sources. According to the invention, the special amyloses are obtained from high-amylose corn starches, i.e. starches with an amylose content above 65 as are commercially available under the names Hylon VII (National Starch) or Eurylon 7 (Roquette), or from high-amylose pea starches.

The special amyloses are preferably obtained from the above starches according to a newly developed method by treatment with formamide solution which contains a small proportion of dichloroacetic acid. The enormous advantage of this method according to the invention is that it enables the starch to be decomposed and chemically modified in one step by treatment with formamide/dichloroacetic acid; this means that, after destruction -4of the granular structure of starch, in particular the molecularweight and chain-length distribution of amylose is changed by decomposition.

According to the invention, the starch is dissolved in the 4- to 6-fold amount of formamide solution which contains 2 weight dichloroacetic acid. The dissolution temperature depends essentially on the type of the starting starch used and ranges between 130 and 180"C. The solution is kept at this temperature for a period between 20 and 40 minutes, preferably 30 minutes. During this period the corn starch is decomposed, and starch degradation starts.

Subsequently, the solution is slowly cooled down to a temperature between 110 and 130'C, preferably 120'C, within a period of 10 to minutes, and after that kept at this temperature for a period of 20 to 40 minutes, preferably 30 minutes. This leads to the molecular-weight and chain-length distributions which bring about the properties that are characteristic of the special amyloses acccording to the invention. The end point of the reaction is indicated by a slight discoloration of the reaction solution.

Further starch degradation is stopped by pouring the hot reaction solution into iced water. To precipitate the reaction product, a sufficient amount of precipitant, e.g. methanol or ethanol, is added to the mixture. The product is separated in a conventional manner, for example by sucking-off. Fur further purification, the product is suspended in water, mixed with acetone, and sucked off again. This procedure is repeated several times. After drying, the product has a moisture content between 5 and 15 The amylose thus produced has properties that cannot be achieved by the conventional decomposition and degradation methods.

If 5 According to the invention, special amyloses may also be specific hydroxyalkyl derivatives of amyloses. Such hydroxyalkyl derivatives are produced according to conventional methods, for example by derivatization in alkaline solution, derivatization in aqueousalkaline suspension, or according to the method of GB-PS 869 192.

The experimental conditions are selected in a manner known to a person skilled in the art such that hydroxyalkyl amyloses with a degree of substitution between 0.02 and 0.15 are obtained. A degree of substitution between 0.05 and 0.1 is preferred. According to the invention, the above high-amylose starches are again used as starting material for producing the desired derivatized amyloses.

The special amyloses according to the invention can also be obtained, however, from potatoe starch according to the method of GB-PS 869 192, taking into account the above reaction parameters; this method, however, involves much higher effort. The production of the special amyloses according to the invention is illustrated by the following examples.

In the production of plastics, the special amyloses are used in a mixture with appropriate plasticizers. Mixtures for achieving the object of the invention are composed of: to 97 weight special amylose and 3 to 40 weight of a plasticizer.

Preferably, the following composition is used: to 95 weight special amylose and to 30 weight of a plasticizer.

Particularly preferred is a composition containing: to 85 weight special amylose and to 20 weight of a plasticizer.

Appropriate plasticizers are plasticizers known from the prior art, in particular polyhydric alcohols. Preferably used are glycerol, diethylene glycol, triethylene glycol, sorbitol, polyvinyl alcohol, citric acid oxide adduct or mixtures of these plasticizers.

;'lp 6 The compositions according to the invention can be used both for thermoplastic molding of shaped parts or for producing sheets or films by casting.

Thermoplastic shaping of molded parts using compositions according to the invention is effected in a conventional manner as used for other thermoplastics according to current plastics-processing methods, for example by injection molding, extrusion, blow molding or by thermoplastic molding methods for producing sheets. The molded parts thus obtained are stable and flexible and show an excellent transparency.

According to the invention, the above-described compositions can also be used in a new method of ,roducing cast sheets; these compositions have first to be dissolved in a sufficient amount of an appropriate solvent and subsequently filtered. It is suitable to effect dissolution and filtration at elevated temperature.

Appropriate solvents are, for example, alcohols, aqueous formaldehyde or dimethyl sulfoxide. A preferred solvent, however, is water. The amount of solvent is suitably selected such that the solution on the one hand is still easy to handle and, on the other, the removal of the solvent for forming the sheets does not yet involve too much effort. The amount of solvent therefore, as a rule, will range between 70 and 100 weight parts, related to the total weight of the composition of special amylose and plasticizer.

It is of great importance for the production of the amylose films and sheets to filter the special amylose that is dissolved in the mixture of solvent and plasticizer prior to forming the sheet, because this obviously eliminates any defects, crystallites and impurities from the special amylose, which otherwise would cause recrystallization of the special amylose and thus deterioration of the quality of the resultant sheet or film.

After filtration, the film is formed by pouring the adequately warm solution onto a substrate, and by subsequent removal of the 7 solvent. The sheets are suitably cast onto flat-ground materials, e.g. glass panes. Polyester sheets are preferably used, because the special amylose film is particularly easy to peel off.

The film cast in this way is suitably dried at a temperature of to 70'C. Drying can be carried out both at atmospheric pressure and at reduced pressure.

This method yields sheets which, after drying, are easy to peel off from the substrate, and which are characterized by excellent clearness and light transmittance. At normal atmospheric humidity, the sheets are stable, transparent, flexible and crease resistant, without becoming subsequently turbid (retrogradation), and they withstand a bending angle of 180'C without fracture of the fold.

These properties are retained for months.

The special amylose according to the invention in the above compositions thus cannot only be processed into films and sheets by the above conventional plastics production processes, but particularly easily also by the casting method according to the invention. All the products according to the invention are characterized by satisfactory tensile strength and elongation; these properties are retained even by films or sheets aged over an extended period of time. As becomes obvious from the following embodiments, an increasing proportion of plasticizer reduces the tensile strength of the special amylose film, while the elongation is markedly increased.

The degradation behavior, the swelling capacity and the resistance to aging can be varied by the moisture content of the films and sheets. Thus, the embrittlement increases with decreasing moisture content. In the same way, the solubility of the sheets and films in water can be adjusted in a conventional manner by the type of plasticizer added, from soluble in cold water via soluble in hot water to slowly swellable and finally waterproof in cold water.

Ulil 8 The sheets and films produced by the casting method according to the invention can be made in arbitrary thicknesses, the common film thickness ranging between 20 and 100 m. It is possible to write on these films with plastic-sheet pens or ball-point pens; they are resistant to oils and fats as well as to organic solvents such as acetone, ethanol, esters, and chlorinated solvents.

The molded parts produced using the compositions according to the invention show a much better transparency and clearness than conventional molding compositions on the basis of normal amyloses or amylose derivatives. In addition, these materials, together with the plasticizers, are much better biodegradable. The films and sheets thus produced are in addition characterized by ecotoxicological acceptability, and by food, soil and skin compatibility, so that they can be used without any problem for packaging food. In addition, the sheets are fast to light, dyeable, can be bonded and sealed and are not hygroscopic. The sheets according to the invention can be used as alternatives to other conventional plastics, such as polyvinyl chloride and polypropylene.

The invention is illustrated by the following examples. All the percentages indicated relate to the total amount of special amylose and plasticizer.

EXAMPLE 1 Special amylose: 90.9 weight Ethylene glycol: 9.1 weight 83.5 g water in a round-bottomed flask was mixed with 1.5 g ethylene glycol and heated to 90'C. 15 g special amylose was slowly added to this solution, with vigorous stirring. Then the solution was heated for 60 minutes to 100'C. The hot solution was filtered through a fritted glass filter, and a film from the filtrate, which still had a temperature of about 500C, was cast onto a plane a :-i 4 0 9 -9surface; this film was dried in a drying cabinet at a temperature between 40 and 70"C. After drying, a clear, transparent, elastic sheet of 100 pm thickness was peeled off from the surface.

EXAMPLE 2 Special amylose: 95.24 weight Ethylene glycol: 4.76 weight In accordance with the method described in Example 1 above, a cast sheet was produced from a solution of 84.25 g water, 0.75 g ethylene glycol and 15 g special amylose.

EXAMPLE 3 Special amylose: 80 weight Ethylene glycol: 20 weight In accordance with the method described in Example 1 above, a cast sheet was produced from a solution of 81,25 g water, 3.75 g ethylene glycol, and 15 g special amylose.

EXAMPLE 4 Special amylose: 95.24 weight Triethylene glycol: 4.76 weight In accordance with the method described in Example 1 above, a cast sheet was produced from a solution of 84.25 g water, 0.75 g triethylene glycol, and 15 g special amylose (hydroxyethyl amylose).

EXAMPLE Special amylose: 90.9 weight Polyvinyl alcohol: 9.1 weight In accordance with the method described in Example 1, a cast sheet was produced from a solution of 83.5 g water, 1.5 g polyvinyl alcohol, and 15 g special amylose (hydroxyethyl amylose).

J- 10 EXAMPLE 6 Special amylose: 66.7 weight Ethylene glycol: 33.3 weight In accordance with the method described in Example 1, a cast sheet was produced from a solution of 77.5 g water, 7.5 g ethylene glycol, and 15 g special amylose (hydroxyethyl amylose).

EXAMPLE 7 Special amylose: 90.9 weight Triethylene glycol: 9.1 weight In accordance with the method described in Example 1, a cast sheet was produced from a solution of 83.5 g water, 1.5 g triethylene glycol, and 15 g special amylose (hydroxyethyl amylose).

EXAMPLE 8 Special amylose: 90.9 weight Glycerol: 9.1 weight A cast sheet was produced according to Example 1, using 9.1 weight glycerol as plasticizer.

EXAMPLE 9 Special amylose: 83.4 Glycerol: 16.6 weight A cast sheet was produced according to Example 1, using 16.6 weight glycerol as plasticizer. The solution was filtered under vacuum.

EXAMPLE Special amylose: 80 weight Glycerol: 20 weight A cast sheet was produced according to Example 1, using weight glycerol as plasticizer. The solution was filtered under vacuum.

11 The properties of the cast sheets described in the above examples as well as in the reference examples are compiled in the following table.

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ui /I I PE~li t( Table Special amylose Special amylose films aged for 24 hrs films aged for 24 hrs Plasticizer Light trans- Film Tensile Film Elongation additive mission thickness strength thickness (DIN 67507) (kg/cm 2 (m) 4.76 Ethylene glycol 89.95 91.6 47.5 107.5 9.3 9.1 Ethylene glycol 84.93 95.0 45.3 112.5 11.7 Ethylene glycol 89.53 93.3 25.4 105.8 6.3 33.3 Ethylene glycol 89.10 100.0 6.3 105.0 50.0 4.76 Triethylene glycol 89.43 71.6 51.3 94.2 7.8 9.1 Triethylene glycol 87.50 56.0 38.2 73.0 7.8 9.1 Polyvinyl alcohol 62.74 93.3 46.7 101.7 7.2 9.1 Glycerol 88.96 50.0 57.3 68.3 8.8 16.6 Glycerol 89.95 76.6 28.6 89.1 10.0 Glycerol 88.10 138.3 19.7 197.5 14.7 ce Iss I 13 EXAMPLE 11 Production of special amylose by treatment with formamide/dichloroacetic acid 120 g high-amylose corn starch Hylon VII (National Starch) is dissolved, with stirring, at 145 to 150"C (internal temperature), in 588 g formamide solution that contains 12 g dichloroacetic acid, and kept at this temperature for 30 minutes. The solution is then cooled down to 120"C (internal temperature) (duration: about minutes) and kept at this temperature for another 30 minutes.

Subsequently, the hot reaction solution is poured into about 300 ml iced water. About 200 ml ethanol is added to this mixture to precipitate the product, which is then sucked off. For purification, the solid residue is supended in 1 liter water and precipitated with the same amount of acetone. This procedure is repeated twice. After drying at room temperature or in the drying cabinet, a white voluminous powder is obtained.

Yield: 180 g special amylose EXAMPLE 12 Production of special amylose by derivatization in alkaline solution 48.6 g high-amylose corn starch Hylon VII or Eurylon 7 is mixed with 150 ml water and introduced into 1200 ml IN NaOH. 13.2 g ethylene oxide (liquefied) is slowly added dropwise to this solution with vigorous stirring, so that the internal temperature does not rise above 20'C, and thereafter stirred for 8 hours. This results in conversion of the starch into low-ethoxylated starch.

The reaction solution is neutralized with concentrated HC1, reduced to a volume of 600 ml, and dialyzed against distilled water (diaphragm: Visking Dyalyse Tubing) for 24 hours. Subsequently, the product is precipitated with methanol and sucked off. In this process, disturbing accompanying substances, e.g. in particular salts and water-soluble starch fragments, are removed. For purification, the product is suspended in acetone, sucked off and dried.

Iii Yield: 40 g special amylose (hydroxyethyl amylose).

f I-L: ~I 14 EXAMPLE 13 Production of special amylose by ethoxylation according to the method of GB-PS 869 192 324 g Hylon VII is added batchwise to 1650 ml IN NaOH and stirred for 2.5 hours. Subsequently, 30 g ethylene oxide (liquefied) is slowly added dropwise and thereafter stirred for 2 1/4 hours. This is followed by neutralization with concentrated sulfuric acid. The neutralized starch solution is added to a solution of 700 g MgSO, x 7 H 2 0 in 2000 ml water and stirred for 20 hours. The resultant turbidities are separated (centrifuge). The solution is mixed with an additional amount of 2 liter MgSO, solution (700 g MgSO, in two liters). After 24 hours, a white, flaky precipitate has formed.

The precipitate is filtered off, washed with cold water to remove MgSO 4 and dried.

Yield: 200 g special amylose (hydroxyethyl amylose).

EXAMPLE 14 7roduction of special amylose by derivatization in aqueous-alkaline suspension 1000 g high-amylose corn starch Hylon VII or Eurylon 7 or highamylose pea starch is added batchwise to a solution of 1200 ml water, 13 g NaOH and 150 g Na,SO 4 and then 360 g propylene oxide is slowly added dropwise. Then, the solution is kept at internal temperature for 8 hours, with vigorous stirring. This is followed by neutralization with IN H 2

SO

4 and sucking off. The product is suspended in about 2 liter methanol and again sucked off. This procedure is repeated twice. The isolated product is dried in air or in the drying cabinet Yield: 1215 g special amylose (hydroxypropyl amylose).

t i I- I r 15 EXAMPLE Production of thermoplastic sheet g of the special amylose obtained according to Examples 11 to 14 is intimately mixed with i.4 5 g ethylene glycol as plasticizer in a kneading machine and pressed into a thin, transparent and elastic sheet at a temperature of 100 at a molding pressure of t, and for a pressing time of 30 minutes, using a heated press.

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Claims (12)

1. Special amylose, which a) is swellable, but not soluble, in liquid water at a temperature of 20'C or below; and b) yields a homogenous, flowable quasi-solution without formation of gels if said amylose is heated, with stirring, to temperatures above 80'C, at atmospheric pressure, the state being maintained, during cooling to a temperature of 50°C and for at least five minutes after reaching without gel formation, said quasi-solution in a concentration between and 25 of said amylose being applicable to knife coating onto a plane surface with a gap width between 100 and 700 p m.

2. Special amylose as claimed in Claim 1, said special amylose being a hydroxyalkyl amylose.

3. Special amylose as claimed in any one of Claims 1 to 2, said special amylose being a hydroxyalkyl amylose with a degree of substitution between 0.02 and 0.15, preferably between 0.05 and 0.1.

4. Special amylose as claimed in any one of Claims 1 to 3, said special amylose being a hydroxyethyl amylose or a hydroxypropyl amylose. Compositions containing special amylose as claimed in any one of Claims 1 to 4, to produce plastics which contain 60 to 97 weight special amylose and 3 to 40 weight of a plasticizer. 6, Compositions as claimed in Claim 5, which contain 70 to 95 weight special amylose and 5 to 30 weight of a plasticizer.

7. Compositions as claimed in Claim 5, which contain 80 to 85 weight special amylose and 15 to 20 weight of a plasticizer. 0 21E NI L 17

8. Compositions as claimed in any one of Claims 1 to 7, wherein the plasticizer is selected from glycerol, diethylene glycol, triethylene glycol, sorbitol, polyvinyl alcohol, citric acid oxide adduct or mixtures thereof.

9. Use of the compositions as claimed in any one of Claims 5 to 8 in processes for the thermal production of molded parts, in particular films and sheets comprising the step of forming moulded parts from the composition by a thermal process. Method of producing amylose films and sheets using the compositions as claimed in any one of Claims 5 to 8, wherein the special amylose is dissolved, possibly with heating, in a mixture of a plasticizer and an appropriate solvent, the resultant solution being filtered, and the sheet being obtained by casting the solution onto an appropriate ii; substrate and subsequently removing the solvent.

11. Method as claimed in Claim 10, wherein the cast film is dried at a temperature .between 20 and 70 0 C.

12. Method as claimed in any one of Claims 10 to 11, wherein the cast film is dried at reduced pressure.

13. Method as claimed in any one of Claims 10 to 12, wherein the solvent is water.

14. Molded parts which are produced using special amyloses of any one of Claims 1 to 4. Special amylose as claimed in Claim 1, obtainable by decomposing, in one step, and chemically modifying, high-amylose corn starch or high-amylose pea starch by treatment with a formamide solution that contains 2 dichloroacetic acid. DATED this 18th day of June 1992. BATTELLE INSTITUT E.V. and EMS-CHEMIE AG WATERMARK PATENT TRADEMARK ATTORNEYS THE ATRIUM 290 BURWOOD ROAD L HAWTHORN VICTORIA 3122 AUSTRALIA SKP/LPS/CH (DOC.14) AU5525590.WPC 7E 4\ ~LLLY ABSTRACT The invention relates to special amyloses for producing biodegradable, clear, transparent and flexible plastic, in particular sheets and films, which a) are swellable, but not soluble, in cold water; b) yield homogenous, flowable quasi-solutions without formation of gels if they are heated, with stirring, to temperatures above 80"C, at atmospheric pressure; during cooling to a temperature of 50"C, this state is maintained for at least five minutes, without gel formation or retrogradation, and the solution in a concentration between 5 and 25 is applicable to knife coating onto a plane surface with a gap width between 100 and 700 im. j, I INTERNATIONAL SEARCH REPORT International Application No PCT/EP 90/00675 I. CLASSIFICATION OF SUBJECT MATTER (if several classification symbols apply, Indicate all) L- According to International Patent Classification (IPC) or to both National Classification and IPC Int.Cl. 5 C 08 B 33/00, C 08 L 3/14, C 08 J 5/18 II. FIELDS SEARCHED Minimum Documentation Searched 7 Classification System IClassification Symbols Int.Cl. 5 C 08 B; C 08 L Documentation Searched other than Minimum Documentation to the Extent that such Documents are Included In the Fields Searched n III. DOCUMENTS CONSIDERED TO BE RELEVANT_ Category I Citation of Document, 11 with Indication, where appropriate, of the relevant passages 12 Relevant to Claim No. 3 Y US, A, 4626288 (TRZASKO ET AL) 2 December 1986, 1 see coTumn 1, line 23 line 47, abstract Y GB, A, 965349 (DEPARTMENT OF AGRICULTURE AND 1 INSPECITION OF THE STATE OF NEBRASKA) 29 July 1964, see column 1, line 13 line 21; column 2, table 1 A 1-2,5-8,9,11 Y GB, A, 869192 (C06PERATIVE VERKOOP-EN 1 PRODUCTIEVERENIGING VAN AARDAPPELMEEL EN DERIVATEN "AVEBE" 31 May 1961, see page 1, line 52 line 66; page 2, line 7 line 19 A US, A, 3549619 (ARTHUR M. MARK ET AL) 22 December 1-2,5-9 1970, see column 1, line 48 line 53; column 2, line 4 line 10; column 3, line 38 line 42 SSpecial categories of cited documents: 10 later document published after the international filing date document defining the general sate of the art which is not or priority date and not in conflict with the application but A" ocmn defng the e ateo the art which is not cited to understand the principle or theory underlying the Iconsidered to be of particular relevance nvention earlier document but published on or after the international document of particular relevance; the claimed invention filing date cannot be considered novel or cannot be considered to document which may throw doubts on priority claim(s) or involve an inventive step which Is cited to establish the publication date of another document of particular relevance; the claimed invention citation or other special reason (as specified) cannot be considered to involve an inventive step when the document referring to an oral disclosure, use, exhibition or document Is combined with one or more other such docu- other means ments, such combination being obvious to a person skilled document published prior to the international filing date but In the art. later than the priority date claimed document member of the same patent family IV. CERTIFICATION Date of the Actual Completion of the International Search Date of Mailing of this International Search Report July 1990 (05.07.90) 26 July 1990 (26.07.90) International Searching Authority Signature of Authorized Officer European Patent Office Form PCT/ISA/210 (second sheet) (January 1985) -2- eMm-m..AW A-6U9to NaPGT/EP 90/00675 gas. ocuuuwrs CuNSbEm so urN AasVANT tosunmumo puoMT "COM gbigM 111? CU99 M a.lo* wwowo to ge Pua noo I ftwm to C401Pm No US, A, 3312641 (AUSTIN H. see column 2, line 10 line 31 line 37 YOUNG) 4 April 1967. line 22; column 2, US, A, 3117014 (EUGENE D. KLUG) 7 January 1964, see column 1, line 27 line 33; cclumr 1. line 48 line 55; cclumn 6, line 49 line 58, table I, examples 5,6 US, A, 2822581 (JOHANNES MUETGEERT ET AL) 11 February 1956, see cclumn 1, line 59 line 68; colurr 3, line 21 line US, A, 2656571 (HOWARD A. DAVIS ET AL) 27 October 1953, see columrn 2. line 10 line 15; column 2 line 21 line 23; column 2, line 28 line 33; column 3, line 35 line 49, column 4, line 44- line 48 US, A, 3314810 (AUSTIN H. YOUNG) 18 April 1967, see. cclun',r 2, line 1 line 7; column 2, line 24 line 27 1 .5-9 1-2,4-9 1 ,5-8 1-2,5-7 j foMi PCT113AMhMO imw SiOW &AMiMPuY 19") I ANNEX TO THE INTERNATIONAL SEARCH REPORT ON INTERNATIONAL PATENT APPLICATION NO.PCT/EP 90/00675 SA 36242 This annex lists the patent family members relating to the patent documents cited in the above-mentioned international search report. The members are as contained in the European Patent Office EDP file on 04/07/90 The European Patent office is in no way liable for theseparticulars which are merely given for the purpose of inlormation. Patent document Publication Patent family Publication cited in search report date member(s) date US-A- 4626288 02/12/86 CA-A- 1236455 10/05/88 EP-A-B- 0188237 23/07/86 JP-A- 61215636 25/09/86 GB-A- 965349 29/07/64 NONE GB-A- 869192 31/05/61 NONE US-A- 3549619 22/12/70 NONE US-A- 3312641 04/04/67 BE-A- DE-A- FR-A- GB-A- NL-A- US-A- US-A- 3117014 07/01/64 DE-A- FR-A- GB-A- NL-A- US-A- 648676 01/10/64 1745680 09/09/71 1419629 00/00/00 1075002 00/00/00 6406933 21/12/64 3314810 00/00/00 1470846 06/02/69 1293184 00/00/00 964799 00/00/00 263573 00/00/00 3117U21 00/00/00 US-A- 2822581 11/02/58 NONE US-A- 2656571 27/10/53 NONE US-A- 3314810 18/04/67 BE-A- 648676 01/10/64 DE-A- 1745680 09/09/71 FR-A- 1419629 00/00/00 GB-A- 1075002 00/00/00 NL-A- 6406933 21/12/64 US-A- 3312641 00/00/00 i i, I For more details about this annex see Official Journal of :he European patent Office, No. 12/82 EPO FORM P0479 INTERNATIONALER RECHERCHENBERIGHT Inlernationales Aktenzeichen PCT/EP 90/00675 1. KIASSIFIKATION DES ANMELJUNGSGENSTANDS (bel mehreren Klassifikationssymbolen sind alle anzugeben) 6 Nach der Internationalen Patentklassilikation (IPC) Oder nach dier nationalen Kiasssihikation und dier IPC lnt.CI. 5 C 08 B 33/00, C 08 L 3/14, C 08 J 5/18 11. RECHEIRCHIERTE SACH-GEBIETE Recherchierter Mindestprulstofl'

111. EINSCHLAGIGE VEROFFENT LICH UNG EN 9 Art jKennzeichnung tier VerollentlichungH ,soweit erforderlich unter Angabe der mra~geblichen Teile t2 Betr. Anspruch Nr) 3 Y US, A, 4626288 (TRZASKO ET AL) 2 Dezember 1986, 1 siehe Spalte 1, Zeile 23 Zeile 47, Zusammenfas sung Y GB, A, 965349 (DEPARTMENT OF AGRICULTURE AND 1 INSPECITION OF THE STATE OF NEBRASKA) 29 Juli 1964, siehe Spalte 1, Zeile 13- Zeile 21; Spalte 2 table 1 A 1-2,5-8, 9,11 Besondere Kategorlen von angegebenen Verotlentlichungen 10 T ptrVekfnlihgdeacdmitraioanA- Veraflentlichung, die den ailgemneinen Stand der Technik TSieeVrfetihndenc e nentoae n definiert, aber nicht ala besonders bedeutsam anzuseh~en ist !neldedatum Oder dem Priorit~tsdatum verollentlicht worden ist und mit tier Anmeltiung nicht kollidiert, sondern nur zumn IE' ilteres Dokument, tias jedoch erst am Oder nach dem interna- Verstindnis des dier Erfindung zugrundeliegetiden Prinzips tionalen Anmeltiedatum verbtfentlicht worden is Oder der ihr zugrundeliegenden Theorie angegeben ist ILI Veroiffentlichung, die geeignet ist, einen Priorititsanspruch IX Veroiftentlichung von besontierer Bedeutung, die beanspruch- sweifethalt erscheinen zu lassen, Oder durch die das Vera?- te Erfindung kann nicht als neu Oder aut erlinderischer Titig- fentli ch ungsdatumn einer anderen im Recherchenbericht ge- keit beruhend betrachtet werden nanoten Veroffentlichung belegi werden soil odev die aus emn- em anderen besonderen Grund angegeben ist (wie ausgefujhrt) Verollentlichung von besonderer Bedeutung, die beanspruch- erdlenlicung diesic au eie mndlihe ffeb~rng, te Erfindung kann rticht als aul erfinderischer Titigkeit be- 0 eroflentlcung, ine Asiaelnger ndee Oflnbarun, ruhend betrachtet werden, wenn die Verolffentlichung mit beiehtniug leAsllun dradr anhe einer Oder mehreren anderen Verotlentlichungen dieser Kate- beziehtgorie in Verbindung gebracht wird und diese Verbindung fdr IP Veroffentlichung, die vor dem internationalen Anmeldeda- einen Facthmann naheliegend ist tumn, aber nach dem beanspruchten Priorititsdatum veroffent- W Veroiffentlichung, die Mitglied derselben Patentfamilie ist licht word~n Is? IV, BESCHEINIGUNG Datum des Abschfusses der internationalen Recherche Absentiedatum des internationalen Recherchenberichis Juli 1990260,0 Internationale Recherchenbehbrde Unterschrilt des bevolimichtigten 13ediensteten Europiisches Patentamt Mine N. KUPER Formblatt PCTIISAJ21O (Blatt 2) (Januar 1985) ternallonales AktenzeicAi, IV. INSHLAIGE VEROFFENTLICHUNGEN (Fortsetzung vonn Batt~drmnelce en 9/07 GB, A, 869192 (CO05PERATIVE VERKOOP- EN PRODUCTIEVERENIGING VAN AARDAPPELMEEL EN DERIVATEN "AVEBE" G.A.) 31 Mai 1961, siehe Seite 1, Zeile 52 Zeile 66; Seite 2, Zeile 7 Zeile 19 US, A, 3549619 (ARTHUR M. MARK ET AL) 22 Dezember 1970, siehe Spalte 1, Zeile 48 Zeile 53; Spalte 2, Zeile 4 Zeile Spalte 3, Zeile 38 Zeile 42 US, A, 3312641 (AUSTIN H. YOUNG) 4 April 1967, siehe Spalte 2, Zeile Zeile 22; Spalte 2, Zeile 31 Zeile 37 US, A, 3117014 (EUGENE 0. KLUG) 7 Januar 1964, siehe Spalte 1, Zeile 27 Zeile 33; Spalte 1, Zeile 48 Zeile Spalte 6, Zeile 49 Zeile 58 Table I, examples 5,6 1 1-2,5-9 1,5-9 1-2,4-9 1,5-8 1 1-2,5-7 US, A, 2822581 11 Februar Zeile 59 Zeile 21 (JOHANNES MUETGEERT ET AL) 1958, siehe Spalte 1, Zeile 68; Spalte 3, Zeile US, A, 2656571 (HOWARD A. DAVIS ET AL) 27 Oktober 1953, siehe Spalte 2, Zeile 10 Zeile 15; Spalte 2, Zeile 21 Zeile 23; Spalte 2, Zeile 28 Zeile 33; Spalte 3, Zeile 35 Zeile 49 Spalte 4, Zeile 44 Zeile 48 US, A, 3314810 (AUSTIN H. YOUNG) 18 April 1967, siehe Spalte 2, Zeile 1A Zeile 7; Spalte 2, Zeile 24 Zeile 27 I Formblatt PCTIISAJ2Io (Zusatzbagen) (Januar i ANHANG ZUNA INTERNATIONALEN RECHERCHENBERICHT OBER DIE INTERNATIONALE PATENTANMELDUNG NR .PCT/EP 90/00675 SA onaisern Anhntnct ulld ate P.Wofecler d'.r Patelaiilen der im obttncenariflten interriationaien Rechercflcnbericlit angeluflrItfl Die Anuzbii uu-r 00 amispnmiitecr vnt.orienn aem Stand or Datei a~s Eurorhiscnien Patentarn:s am,04,'07/90 Diese 4noatt1OL utnin nur zur Unvierntn'ji uno eriolan onne Gpwwarn 36242 it- Recnercrnnprich1 Datum der *Mitoa~e r) der Datum der oclunries Patentaoi~ument v(ronientil..~ Patentanilte Verollentlichng US-A- 4626288 02/12/86 CA-A- 1236455 10/05/88 EP-A-B- 0188237 23/07/86 JP-A- 61215636 25/09/86 GB-A- 965349 29/07/64 KEINE GB-A- 869192 31/05/61 KE I N E US-A- 549619 22/12/70 KEINE US-A- 3312641 04/04/67 BE-A- 648676 01/10/64 DE-A- 1745680 09/09/71 FR-A- 1419629 00/00/00 GB-A- 1075002 00/00/00 NL-A- 6406933 21/12/64 US-A- 3314810 00/00/00 US-A- 3117014 07/01/64 DE-A- 1470846 06/02/69 FR-A- 1293184 00/00/00 GB-A- 964799 00/00/00 NL-A- 263573 00/00/00 US-A- 3117021 00/00/00 US-A- 2822581 11/02/58 KEINE US-A- 2656571 27/10/53 KEINE US-A- 3314810 18/04/67 BE-A- 648676 01/10/64 DE-A- 1745680 09/09/71 FR-A- 1419629 00/00/00 GB--A- 1075002 00/00/00 NL-A- 6406933 21/12/64 US-A- 3312641 00/00/00 r FUr nihere Einzelheiten zu diesemn Anhang :siehe Amntsblatt des Europiischen Patentamnts, Nr.12i82 EPO FORM P0473