Title of Invention	BIODEGRADABLE COMPOSITIONS BASED ON NANOPARTICULATE STARCH
Abstract	Abstract BIODEGRADABLE COMPOSITIONS BASED ON NANOPARTICULATE STARCH The present invention relates to biodegradable multiphase compositions comprising a continuous phase composed of a matrix of at least one tough hydrophobic polymer incompatible with the starch and a nanoparticulate dispersed starch phase with mean dimensions of less than 0.25 m. The compositions are characterized by breaking load. Young's Modulus and breaking energy.

Title of Invention

BIODEGRADABLE COMPOSITIONS BASED ON NANOPARTICULATE STARCH

Abstract

Abstract BIODEGRADABLE COMPOSITIONS BASED ON NANOPARTICULATE STARCH The present invention relates to biodegradable multiphase compositions comprising a continuous phase composed of a matrix of at least one tough hydrophobic polymer incompatible with the starch and a nanoparticulate dispersed starch phase with mean dimensions of less than 0.25 m. The compositions are characterized by breaking load. Young's Modulus and breaking energy.

Full Text	BIODEGRADABLE COMPOSITIONS BASED ON NANOPARTICULATE STARCH DESCRIPTION The present invention relates lo biodegradable multiphase compositions based on starch, capable of being transformed into flexible films with longitudinal tensile properties in traction at 23°C, 50% RH that give rise to a K. factor greater than 28, preferably greater lhan 30 and even more preferably greater than 33, defined as follows; K = (Breaking load) x (Young's Modulus) x (Breaking energy) / 1,000.000 with Breaking load and Young's modulus expressed in MPa and Breaking energy in KJ/m . These films have no phenomena of transverse tearing even at relative humidity of less than 20% and at 23°C and are particularly suitable for producing very tough bags and wrappings. These properties are even more noteworthy as they refer to films obtained without post-film stretching. The compositions according to the present invention are water insoluble and not water dispersible according to the standard UNI 10956 or EN 149K7. In particular, the present invention relates to multiphase biodegradable compositions comprising at least two phases: (a) a continuous phase composed of a matrix of al least one tough hydrophobic polymer incompatible with starch, said polymer being selected from the class of polyesters from diacid-diol; (b) a homogeneously dispersed nanoparticulate starch phase with mean dimensions of less than 0.25 jun, preferably less than 0.20 urn, and even more preferably less than 0.18 \|im; wherein the K factor is greater than 28, preferably greater than 30 and even more preferably greater than 33. The dimensions of starch particles arc measured in the transverse section with respect to the direction of the extrusion flow or, anyhow, with respect to the direction of material's output. The dimension of a starch particle is therefore measured on the bidimensional shape resulting from the transverse section. The mean dimension of the starch particles is calculated as the numeral (or arithmetic) average of the particles dimensions. In case of a spherical particle the dimension of the particle corresponds to the diameter of a circle. In case of a non-spherical particle the dimension (d) of the particle is calculated according to the following formula: J_ i > i where di is the minor diameter and d: is the majordiamctcroftheellip.se in which the particle can be inscribed or approximated. Preferably, the compositions according to the preseni invention have a distribution of the starch panicles such an: - dimension of 80% of the starch particles is less than 0,35 urn; - the area of such 80% starch particles is greater than 45% with respect to the total area of the starch particles. Particularly preferred according to the present invention arc compositions witli a distribution of the starch particles such as: - dimension of 80% of the starch particles is less than 0.25 um; - the area of such K0% starch particles is greater than 50% with respect to the total area of the starch particles. One drawback of the starch-based biodegradable bags currently present on the market is represented by the lack of uniformity of the mechanical properties, in particular tear strength, in the transverse and longitudinal directions. Shopping bags measuring 60 x 60 cm used by large-scale retailers are prevalently made of PE with thicknesses of around 18-20 (.im, while at these thicknesses, starch-based biodegradable films arc still too yielding or too fragile to withstand certain limits of weight (i.e. 10 kg). These limits in performance arc particularly apparent in conditions of low humidity. The aforesaid technical problem has now been solved with the biodegradable compositions based on starch, according to the present invention which, having a high load, a modulus superior to that of a normal LDPE and extremely high tenacity in the two directions, without any transverse displacement, are particularly advantageous for producing thin films. In fact, the present biodegradable compositions allow bags with thicknesses in the order of 18-20 urn and even with thicknesses lower than 18 um if needed from a practical application, to be produced, in other words, with thicknesses comparable to bags made of the medium density polyethylene. It is also possible to produce "loop-handle" bags with dimensions of approximately 70 x 70 cm and thicknesses in the order of 50 um, the same thickness as LDPE loop-handle bags. The present compositions arc biodegradable according to the standard EN 13432. In particular, the materials according to the present invention comprise; (a) with regard to the hydrophobic matrix, at least one tough thermoplastic polymer incompatible with the starch and in the continuous phase between 55 and 95%. preferably between 58 and 90%. more preferably between 60 and 85%, and even more preferably between 62 and 80%; (b) with regard to the dispersed starch phase, al least one desimcturized nanoparticulate starch in a percentage between 5 and 45%, preferably between 10 and 42%, more preferably between 15 and 40% and even more preferably between 20 and 38%. To obtain a material with breaking load, and tenacity in the two transverse and longitudinal directions, superior to the materials described in prior art it is necessary to u.se specific weight ratios of the various components, and to use a process in the extruder or any other machine capable of providing temperature and shear conditions that allow reduction of the dispersed phases in very small particles. In general, the most suitable extrusion systems are those that use laminating screws with a ratio between the maximum and minimum diameter of the screw of less than J.6 and more preferably less than 1.4. With regard to the hydrophobic matrix, tough polyesters from diacid-diol are taken into consideration herein, i.e. polyesters characterized by Modulus of less than 200 MPa and ultimate elongation greater than 500%, such as the aliphatic aromatic polyesters from diacid/diol of the type described in EP 559 785 (Eastman), EP 792 309 (BASF) and WO 2006/097353 (Novamont). Within the limits indicated, aliphatic polyesters from diacid/diol of the type described in EP 1 117 738 are also taken into consideration here. Particularly preferred arc polyesters in which the diacid moiety is chosen from at least one of the following diacids: succinic, adipic, azelaic, sebacic, undecandioic, dodecandioic, brassylic acid or mixtures thereof. Even more preferred are polyesters from diacid-diol in which the diacid moiety, in addition to the diacids mentioned above, contains also aromatic diacids. Said aromatic acids are chosen from the group consisting of dicarboxylic compounds of the phtalic-acid type and their esters, preferably tcrephthalic acid. Said aromatic acids arc present in an amount 49 to 66 mo I %, preferably 49.5 to 63 mol%, still more preferably 50 to 61 mol% with respect to the total amount of the acid components. During the polymer synthesis process various additives such as polycarbodiimides, poiyepoxy resins, peroxides and oxazolincs can also be added. Particularly poiyepoxy resins can be advantageously added as additives in order to stabilize the final multiphase composition against hydrolysis. Particular!) preferred are resins of the glycidyl type. Still more preferred is BADGE (bisphenol A diglycidyl ether). With regard to the starch phase, al! native starches arc included here, such as those from potato, corn, tapioca, pea, rice, wheat and also high-amylose starch -- preferably containing more than 30% by weight of amylose - and waxy starches. Compositions containing destructurized starch are preferred. Starches such as corn and potato starch, capable of being easily destructurizable and which have high initial molecular weights, have proven to be particularly advantageous. The use of corn and potato starch is particularly preferred. For destructurized starch, the teachings contained in EP-0 1 18 240 and EP-0 327 505 arc referred to here, this being intended as starch processed so that il substantially has no "Maltese crosses" under the optical microscope in polarized light and no "ghosts" under the optical microscope in phase contrast. Furthermore, physically and chemically modified starch grades can be in part used, such as cthoxylated starches, oxypropylatcd starches, starch acetates, starch butyratc, starch propionates, with a substitution degree comprised within the range of from 0.1 to 2, cationic starches, oxidized starches, crosslinked starches, gelled starches. The compositions according to the present invention show good properties also in case of starch blends in which the starch is not strongly completed. With regard to the complexation of the starch, the teachings contained in EP-0 965 615 AI have to be intended as incorporated in the present description. The presence of the complexes of starch with one tough hydrophobic polymer incompatible with the starch can be demonstrated by the presence in the X-ray diffraction spectra of a peak in the range of the 13-14° on the 2 theta scale. According to the present invention, with the wording compositions in which the starch is not strongly complexed arc intended the compositions where the Hc/Ha ratio between the height of the peak (He) in the range of 13-14° of the complex and the height of the peak (Ha) of the amorphous starch which appears at about 20.5° is less than 0.15 and even less than 0.07. The compositions according to the invention can contain further dispersed phases composed, for example, of rigid polymers, in particular polyhydroxyalkanoates, such as polylactic acid and polyglycolic acid. Particularly preferred arc polymers or copolymers of polylactic acid containing at least 75% of L-lactic or D-lactic acid or combinations thereof, with molecular weight Mw greater than 70,000 and with a modulus greater than 1,500 MPa. These polymers can also be plasticizcd. In the format ion phase of the multiphase structure of the present biodegradable compositions there must be at least one plaslicizcr for the starch to provide suitable theological properties to minimize the dimensions of the starch phase. This plasticizcr can simply be water (even the water contained in the native starch alone without the need for further additions), or self-boiling or polymer plasticizers. The quantity of plasticizer is generally chosen on the basis of rheological needs and of the mixing system. In any case, plasticizers can be added in a quantity of less than 10% in relation to. the components {A + B). Besides water, plasticizers that can be utilized in the compositions according to the invention are. for example, those described in WO 92/14782, with glycerol as the particularly preferred plasticizcr. Compositions containing water as the only plasticizer are preferred. Compositions containing the water present in native starch as the only plasticizcr are particularly preferred In the present biodegradable compositions various additives can also be incorporated, such as antioxidants, UV stabilizers, heat and hydrolysis stabilizers, chain extenders, flame retardants, slow release agents, inorganic and organic fillers, such as natural fibres, antistatic agents, wetting agents, colorants, lubricants or compatibihzing agents among the various phases. Examples of hydrolysis stabilizers are polycarbodiimides and epoxy resins. Among polycarbodiimides particularly preferred are aliphatic polycarbodiimides. Among epoxy resins particularly preferred are epoxidized polymcthacrylates, in particular of the glycidyl type. The most preferred is a poly epoxy propyl mcthacrylatc. Example of chain extenders are peroxides. Among peroxides particularly preferred are organic peroxides. Thanks to the nanoparticuiate dispersed starch phase, the biodegradable multiphase compositions according to the invention are particularly suitable for being transformed into flexible films with high modulus and at the same time provided with isotropy in the two longitudinal and transverse directions, in particular in relation to tear strength. Said films arc particularly suitable for producing bags and wrappings capable of supporting heavy weights without severe deformations and without the occurrence of transverse fractures. The films obtained from (he biodegradable multiphase composition according to the invention can also be used to make sacks and bags for carrying goods, film and bags for food packaging, strctchable, heat-shrinkablc film, film for adhesive tape, for disposable nappy tapes and for decorative coloured tapes. Some other main applications arc for silage, for breathable bags for fruit and vegetables, bags for bread and other food products, film for covering packs of meats, cheese and other food items and yoghurt pots. Due to their properties, the biodegradable multiphase compositions according to the invention can also find application in the field of textiles and non-woven fabric for clothing, co-extruded fibers and spun-bonded, hygiene and industrial products, and also for fishing nets or nets fruit and vegetables. The present invention is now illustrated with reference to some non-limiting examples thereof. The present invention is now illustrated with reference to some non-limiting examples thereof. Examples The compositions are expressed in parts. Rcoflex is a polybutylene adipate-co-terephthalate produced by BASF AG. The compositions indicated in Table 1 were fed to a co-rotating extruder with L/D = 36 and diameter 60 mm with 9 heating zones. The extrusion parameters are as follows: RPM: 140 Flow rate: 40 kg I hour Thermal profile 60-140-175-1KO\4-155\2T Screw diameter ratio (max. diam. / min. diam.) 1.31-1.35 Ratio between transport and mixing zones: 2:1 Degassing in zone 8 out of 10 Final water content of the granule equal to 0.8% The compositions of Table 1 were filmed on a 40 mm Ghioldi machine, die yap = 1 mm, flow rate 20 kg/h to obtain film with a thickness of 20 u,m. The 20 um films were then subjected to mechanical characterization according to the standard ASTM D882 (traction at 23°C and 55%; Relative humidity and Vo = 50 mm7min). The results arc indicated in Tabic 2 below. The granules of the compositions according to examples I and 2 were fractured, subjected to acid etching to eliminate the starch particles, then a micro photography was performed with x4000 magnification under the Scanning Electron Microscope (SEM). The microphotographs relating to Example 1 and 2 arc shown in Figure 1 and 2, respectively. They show: - a dimension of the starch nanoparticles with a numeric mean of less than 0.25 urn; - a distribution of the starch nanoparticles such as: - dimension of 80% of them is less than 0.2 urn; - the area of such 80% is greater than 45% with respect to the total area of the starch particles. Example 3 (comparison) The example n°5 of the patent EP 0 965 615 Al was repeated. The composition obtained according to said example was filmed with a thickness of 20 um. The table below (Table 3) shows the mechanical properties of the resulting film. The film of the composition according to example 3 was fractured, subjected to acid etching to eliminate the starch particles and microphotography was performed with x4000 magnification under the Scanning Electron Microscope (SEM). The microphotographs relating to Example 3 is shown in Figure 3. The microphotograph shows: - a dimension of the starch nanoparticles with a numeric mean of 0.43 urn; - a distribution of the starch nanoparticles such as: - dimension of 80% of them is less than or equal to 0.56 urn; CLAIMS Multiphase biodegradable compositions comprising at least two phases: (a) a continuous phase composed of a matrix of at least one tough hydrophobic polymer incompatible with starch, said polymer being selected from the class of polyesters from diacid-diol; (b) a homogeneously dispersed nanoparticulate starch phase; wherein a film of a thickness of 20 um obtained from said compositions and tested according to ASTM D822 is characterized by a K factor greater than 28 and by numeric mean dimensions of the particles of said dispersed starch phase (b) of less than 0.25 um> wherein the K factor is defined by the following formula K = (Breaking load) x (Young's Modulus) x (Breaking energy)/1,000,000 With Breaking load and Young's Modulus expressed in MPa and Breaking energy in KJ/m2. Multiphase biodegradable compositions according to claim 1, characterized by K factor greater than 30. Multiphase biodegradable compositions according to claim 1, characterized by K factor greater than 33. Multiphase biodegradable compositions according to claim 1, characterized by a dispersed starch phase with in particles having mean dimensions of less than 0.20 urn Multiphase biodegradable compositions according to claim 1, characterized by a dispersed starch phase with in particles having mean dimensions of less than 0.18 um. Multiphase biodegradable compositions according to claim 1, characterized by a distribution of the starch nanopaitides is as follows: - dimension of 80% of the starch particles is less than 0.35 um; - the area of such 80% starch particles is greater than 45% with respect to the total area of the starch particles. Multiphase biodegradable ompositions according to claim 1, characterized in that: (a) said matrix comprises at least one tough thermoplastic polymer incompatible with starch in the continuous phase in an amount from 55 to 95%; (b) said dispersed starch phase comprises at least one destructurized nanoparticulate starch in an amount from 5 to 45%. Multiphase biodegradable compositions according to claim 1, characterized in that: (a) said matrix comprises at least one tough thermoplastic polymer incompatible with starch in the continuous phase in an amount from 58 to 90%; (b) said dispersed starch phase comprises at least one destructurized nanoparticulate starch in an amount from 10 to 42%. 9- Multiphase biodegradable compositions according to claim 1, characterized in that: (a) said matrix comprises at least one tough thermoplastic polymer incompatible with starch in the continuous phase in an amount from 60 to 85%; (b) said dispersed starch phase comprises at least one destructurized nanoparticulate starch in an amount from 15 to 40%. 10. Multiphase biodegradable compositions according to claim 1, characterized in that: (a) said matrix comprises at least one tough thermoplastic polymer incompatible with starch in the continuous phase in an amount from 62 !o 80%; (b) said dispersed starch phase comprises at least one destructurized nanoparticulate starch in an amount from 20 to 38%. 11. Multiphase biodegradable compositions according to claim 1, wherein said tough thermoplastic polymer is characterized by Modulus of leas than 200 MPa. 12. Multiphase biodegradable compositions according to claim 1, characterized by an ultimate elongation greater than 500%. 13. Multiphase biodegradable compositions according to claim 1, characterized in that said polyester comprises a diacid moiety derived from a diacid selected from the group consisting of the following aliphatic diacids: succinic, ndipic, azelaic, sebacic, undecandioic, dodecandioic, brassylic acid or mixtures thereof. 14. Multiphase biodegradable compositions according to claim 1, characterized in that said polyester comprises a diacid moiety derived from a at least one aromatic diacid. 15. Multiphase biodegradable compositions according to claim 14, characterized in that said diacid moiety is selected from the group consisting of dicarboxylic compounds of the phtalic-acid type and their esters, \6. Multiphase biodegradable compositions as claimed in claim 15, characterized in that said dicarboxylic compound of the phtalic-acid type is a compound of terephthalic acid, 17. Multiphase biodegradable compositions according to claim 16, characterized in that said terephthalic acid is present in an amount from 49 to 66 mol % with respect to the total amount of the acid components. 18. Multiphase biodegradable compositions according to claim 16, characterized in that said terephthalic acid is present in an amount from 49.5 to 63 mol% with respect to the total amount of the acid components, 19- Multiphase biodegradable compositions according to claim 16, characterized in that said terephthalic acid is present in an amount from 50 to 61 mol% with respect to the total amount of the acid components. 20. Multiphase biodegradable compositions according to claim 1, characterized in that said matrix of at least one tough hydrophobic polymer comprises additives selected ftom polycarbodiimides, polyepoxy resins, peroxides or oxazolines. 21. Multiphase biodegradable compositions as claimed in the previous claim, wherein said additives arc polyepoxy resins. 22. Multiphase biodegradable compositions as claimed in the previous claim, wherein polyepoxy resins are bisphenol A diglycidyl ether. 23. Multiphase biodegradable compositions according to claim i, characterized in that said dispersed starch phase (b) is made of native starch. 24. Multiphase biodegradable compositions as claimed in the previous claim wherein native starch is selected from the group consiting of potato, com, tapioca, pea, rice, wheat, hrgh-amylose starch - preferably containing more than 30% by weight of amylose - and waxy starch. 25. Multiphase biodegradable compositions as claimed in the previous claim, wherein native starch is destructurized native starch. 26. Multiphase biodegradable compositions as claimed in the previous claim, wherein the destructurized native starch is potato and com starch. 27. Multiphase biodegradable compositions as claimed in the previous claim, wherein the destructurized native starch is potato starch. 28. Multiphase biodegradable compositions according to claim 1, characterized in that said dispersed starch phase (b) comprises physically and chemically modified starches. 29. Multiphase biodegradable compositions according to claim 28, characterized in that said physically and chemically modified starches are selected from the group consisting of: ethoxylated starches, oxypropylated starches, starch acetates, starch butyrate, starch propionates, with a substitution degree comprised within the range of from 0.1 to 2, cationic starches, oxidized starches, cross-linked starches, gelled starches. 30. Multiphase biodegradable compositions according to claim 1, characterized in that said further dispersed phase comprises apolyhydroxyalkanoate. 31. Multiphase biodegradable compositions as claimed in the previous claim, wherein said polyhydroxyalkanoate is a polymer or copolymer of polylactic acid with molecular weight Mw greater than 70,000 and with a modulus greater than 1,500 MPa. 32. Multiphase biodegradable compositions according to claim 1, characterized in that in the formation phase of the multiphase structure, at least one plastici^er for the starch is present. 33. Multiphase biodegradable compositions according to claim 1, characterized by containing plasticizers in quantities ofless than 10% in relation to the stun of (a) + (b). 34. Multiphase biodegradable compositions as claimed in the previous claim, wherein the plaslicizer is water or glycerol, or mixtures of both. 35. Multiphase biodegradable compositions as claimed in the previous claim, wherein the plasticizer is the water contained in the native starch. 36. Multiphase biodegradable compositions according to claim 1, characterized in that said in the formation phase of said compositions, additives other than plasticizers are added. 37. Multiphase biodegradable compositions as claimed in the previous claim wherein said additives are selected from antioxidants, UV stabilizers, heat and hydrolysis stabilizers, chain extenders, flame retardants, slow release agents, inorganic and organic fillers, such as natural fibres, antistatic agents, welting agents, colorants, lubricants or compatibilizing agents between the various phases. 38. Multiphase biodegradable compositions as claimed in the previous claim wherein hydrolysis stabilizers are carbodiimides and epoxy resins. 39. Multiphase biodegradable compositions as claimed in the previous claim wherein carbodiimides are aliphatic carbodiimides. 40. Multiphase biodegradable compositions as claimed in claim 38 wherein epoxy resins^are epoxidized polymethacrylates, 41. Multiphase biodegradable compositions as claimed in the previous claim wherein epoxidized polymethacrylates are of the glycidyl type. 42. Multiphase biodegradable compositions as claimed in the previous claim wherein epoxidized polyinethacrylate of the glycidyl type is a poly epoxy propyl methacrylate. 43. Multiphase biodegradable compositions according to claim 1, obtained by processing the components thereof in an extruder or other machine capable of providing temperature and shear conditions that allow a reduction of the dimensions of the particles of said dispersed starch phase (b) to less than 0,25 urn, 44. Film produced with multiphase biodegradable compositions according to claim 1. 45. Bags or sacks, extruded or thermoforraed, laminated with paper, aluminium, plastic and bioplastics, multiperforated produced with film as claimed in the previous claim. 46. Film according to claim 44 for food packaging, stretchable, heat-shrinkable film, film for adhesive tape, for disposable nappy tapes and for decorative coloured tapes, film for covering packs of meats, cheese and other food items and yoghurt pots, film for silage. 47. Use of bags according to the claim 45 for carrying goods, for food packaging, as breathable bags for fruit and vegetables, bags for bread and other food products. 48. Textiles and non-woven fabric for clothing, coextruded fibers and spun bonded, hygiene and industrial products, including fishing nets or nets for fruit and vegetables produced with the substantially water insoluble biodegradable multiphase compositions as claimed in claim 1,

Full Text

BIODEGRADABLE COMPOSITIONS BASED ON NANOPARTICULATE STARCH
DESCRIPTION The present invention relates lo biodegradable multiphase compositions based on starch, capable of being transformed into flexible films with longitudinal tensile properties in traction at 23°C, 50% RH that give rise to a K. factor greater than 28, preferably greater lhan 30 and even more preferably greater than 33, defined as follows; K = (Breaking load) x (Young's Modulus) x (Breaking energy) / 1,000.000 with Breaking load and Young's modulus expressed in MPa and Breaking energy in KJ/m . These films have no phenomena of transverse tearing even at relative humidity of less than 20% and at 23°C and are particularly suitable for producing very tough bags and wrappings. These properties are even more noteworthy as they refer to films obtained without post-film stretching.
The compositions according to the present invention are water insoluble and not water dispersible according to the standard UNI 10956 or EN 149K7.
In particular, the present invention relates to multiphase biodegradable compositions comprising at least two phases:
(a) a continuous phase composed of a matrix of al least one tough hydrophobic polymer incompatible with starch, said polymer being selected from the class of polyesters from diacid-diol;
(b) a homogeneously dispersed nanoparticulate starch phase with mean dimensions of less than 0.25 jun, preferably less than 0.20 urn, and even more preferably less than 0.18 |im;
wherein the K factor is greater than 28, preferably greater than 30 and even more
preferably greater than 33. The dimensions of starch particles arc measured in the transverse section with respect to the direction of the extrusion flow or, anyhow, with respect to the direction of material's output. The dimension of a starch particle is therefore measured on the bidimensional shape resulting from the transverse section.
The mean dimension of the starch particles is calculated as the numeral (or arithmetic) average of the particles dimensions.
In case of a spherical particle the dimension of the particle corresponds to the diameter of a circle.

In case of a non-spherical particle the dimension (d) of the particle is calculated according to
the following formula: J_ i > i
where di is the minor diameter and d: is the majordiamctcroftheellip.se in which the particle can be inscribed or approximated.
Preferably, the compositions according to the preseni invention have a distribution of the starch panicles such an:
- dimension of 80% of the starch particles is less than 0,35 urn;
- the area of such 80% starch particles is greater than 45% with respect to the total area of the starch particles.
Particularly preferred according to the present invention arc compositions witli a distribution of the starch particles such as:
- dimension of 80% of the starch particles is less than 0.25 um;
- the area of such K0% starch particles is greater than 50% with respect to the total area of the starch particles.
One drawback of the starch-based biodegradable bags currently present on the market is represented by the lack of uniformity of the mechanical properties, in particular tear strength, in the transverse and longitudinal directions. Shopping bags measuring 60 x 60 cm used by large-scale retailers are prevalently made of PE with thicknesses of around 18-20 (.im, while at these thicknesses, starch-based biodegradable films arc still too yielding or too fragile to withstand certain limits of weight (i.e. 10 kg). These limits in performance arc particularly apparent in conditions of low humidity.
The aforesaid technical problem has now been solved with the biodegradable compositions based on starch, according to the present invention which, having a high load, a modulus superior to that of a normal LDPE and extremely high tenacity in the two directions, without any transverse displacement, are particularly advantageous for producing thin films. In fact, the present biodegradable compositions allow bags with thicknesses in the order of 18-20 urn and even with thicknesses lower than 18 um if needed from a practical application, to be produced, in other words, with thicknesses comparable to bags made of the medium density polyethylene. It is also possible to produce "loop-handle" bags with dimensions of approximately 70 x 70 cm and thicknesses in the order of 50 um, the same thickness as LDPE loop-handle bags. The present compositions arc biodegradable according to the standard EN 13432.

In particular, the materials according to the present invention comprise;
(a) with regard to the hydrophobic matrix, at least one tough thermoplastic polymer incompatible with the starch and in the continuous phase between 55 and 95%. preferably between 58 and 90%. more preferably between 60 and 85%, and even more preferably between 62 and 80%;
(b) with regard to the dispersed starch phase, al least one desimcturized nanoparticulate starch in a percentage between 5 and 45%, preferably between 10 and 42%, more preferably between 15 and 40% and even more preferably between 20 and 38%.
To obtain a material with breaking load, and tenacity in the two transverse and longitudinal
directions, superior to the materials described in prior art it is necessary to u.se specific weight
ratios of the various components, and to use a process in the extruder or any other machine
capable of providing temperature and shear conditions that allow reduction of the dispersed
phases in very small particles.
In general, the most suitable extrusion systems are those that use laminating screws with a
ratio between the maximum and minimum diameter of the screw of less than J.6 and more
preferably less than 1.4.
With regard to the hydrophobic matrix, tough polyesters from diacid-diol are taken into
consideration herein, i.e. polyesters characterized by Modulus of less than 200 MPa and
ultimate elongation greater than 500%, such as the aliphatic aromatic polyesters from
diacid/diol of the type described in EP 559 785 (Eastman), EP 792 309 (BASF) and WO
2006/097353 (Novamont). Within the limits indicated, aliphatic polyesters from diacid/diol of
the type described in EP 1 117 738 are also taken into consideration here.
Particularly preferred arc polyesters in which the diacid moiety is chosen from at least one of
the following diacids: succinic, adipic, azelaic, sebacic, undecandioic, dodecandioic, brassylic
acid or mixtures thereof.
Even more preferred are polyesters from diacid-diol in which the diacid moiety, in addition to
the diacids mentioned above, contains also aromatic diacids.
Said aromatic acids are chosen from the group consisting of dicarboxylic compounds of the
phtalic-acid type and their esters, preferably tcrephthalic acid. Said aromatic acids arc present
in an amount 49 to 66 mo I %, preferably 49.5 to 63 mol%, still more preferably 50 to 61
mol% with respect to the total amount of the acid components.
During the polymer synthesis process various additives such as polycarbodiimides, poiyepoxy
resins, peroxides and oxazolincs can also be added. Particularly poiyepoxy resins can be

advantageously added as additives in order to stabilize the final multiphase composition
against hydrolysis. Particular!) preferred are resins of the glycidyl type. Still more preferred is
BADGE (bisphenol A diglycidyl ether).
With regard to the starch phase, al! native starches arc included here, such as those from
potato, corn, tapioca, pea, rice, wheat and also high-amylose starch -- preferably containing
more than 30% by weight of amylose - and waxy starches. Compositions containing
destructurized starch are preferred.
Starches such as corn and potato starch, capable of being easily destructurizable and which
have high initial molecular weights, have proven to be particularly advantageous.
The use of corn and potato starch is particularly preferred.
For destructurized starch, the teachings contained in EP-0 1 18 240 and EP-0 327 505 arc
referred to here, this being intended as starch processed so that il substantially has no
"Maltese crosses" under the optical microscope in polarized light and no "ghosts" under the
optical microscope in phase contrast.
Furthermore, physically and chemically modified starch grades can be in part used, such as
cthoxylated starches, oxypropylatcd starches, starch acetates, starch butyratc, starch
propionates, with a substitution degree comprised within the range of from 0.1 to 2, cationic
starches, oxidized starches, crosslinked starches, gelled starches.
The compositions according to the present invention show good properties also in case of
starch blends in which the starch is not strongly completed. With regard to the complexation
of the starch, the teachings contained in EP-0 965 615 AI have to be intended as incorporated
in the present description. The presence of the complexes of starch with one tough
hydrophobic polymer incompatible with the starch can be demonstrated by the presence in the
X-ray diffraction spectra of a peak in the range of the 13-14° on the 2 theta scale. According
to the present invention, with the wording compositions in which the starch is not strongly
complexed arc intended the compositions where the Hc/Ha ratio between the height of the
peak (He) in the range of 13-14° of the complex and the height of the peak (Ha) of the
amorphous starch which appears at about 20.5° is less than 0.15 and even less than 0.07.
The compositions according to the invention can contain further dispersed phases composed,
for example, of rigid polymers, in particular polyhydroxyalkanoates, such as polylactic acid
and polyglycolic acid. Particularly preferred arc polymers or copolymers of polylactic acid
containing at least 75% of L-lactic or D-lactic acid or combinations thereof, with molecular
weight Mw greater than 70,000 and with a modulus greater than 1,500 MPa. These polymers

can also be plasticizcd.
In the format ion phase of the multiphase structure of the present biodegradable compositions there must be at least one plaslicizcr for the starch to provide suitable theological properties to minimize the dimensions of the starch phase. This plasticizcr can simply be water (even the water contained in the native starch alone without the need for further additions), or self-boiling or polymer plasticizers. The quantity of plasticizer is generally chosen on the basis of rheological needs and of the mixing system.
In any case, plasticizers can be added in a quantity of less than 10% in relation to. the components {A + B). Besides water, plasticizers that can be utilized in the compositions according to the invention are. for example, those described in WO 92/14782, with glycerol as the particularly preferred plasticizcr.
Compositions containing water as the only plasticizer are preferred. Compositions containing the water present in native starch as the only plasticizcr are particularly preferred In the present biodegradable compositions various additives can also be incorporated, such as antioxidants, UV stabilizers, heat and hydrolysis stabilizers, chain extenders, flame retardants, slow release agents, inorganic and organic fillers, such as natural fibres, antistatic agents, wetting agents, colorants, lubricants or compatibihzing agents among the various phases. Examples of hydrolysis stabilizers are polycarbodiimides and epoxy resins. Among polycarbodiimides particularly preferred are aliphatic polycarbodiimides. Among epoxy resins particularly preferred are epoxidized polymcthacrylates, in particular of the glycidyl type. The most preferred is a poly epoxy propyl mcthacrylatc. Example of chain extenders are peroxides. Among peroxides particularly preferred are organic peroxides.
Thanks to the nanoparticuiate dispersed starch phase, the biodegradable multiphase compositions according to the invention are particularly suitable for being transformed into flexible films with high modulus and at the same time provided with isotropy in the two longitudinal and transverse directions, in particular in relation to tear strength. Said films arc particularly suitable for producing bags and wrappings capable of supporting heavy weights without severe deformations and without the occurrence of transverse fractures. The films obtained from (he biodegradable multiphase composition according to the invention can also be used to make sacks and bags for carrying goods, film and bags for food packaging, strctchable, heat-shrinkablc film, film for adhesive tape, for disposable nappy tapes and for decorative coloured tapes. Some other main applications arc for silage, for

breathable bags for fruit and vegetables, bags for bread and other food products, film for covering packs of meats, cheese and other food items and yoghurt pots. Due to their properties, the biodegradable multiphase compositions according to the invention can also find application in the field of textiles and non-woven fabric for clothing, co-extruded fibers and spun-bonded, hygiene and industrial products, and also for fishing nets or nets fruit and vegetables.
The present invention is now illustrated with reference to some non-limiting examples thereof.
The present invention is now illustrated with reference to some non-limiting examples thereof. Examples

The compositions are expressed in parts. Rcoflex is a polybutylene adipate-co-terephthalate
produced by BASF AG.
The compositions indicated in Table 1 were fed to a co-rotating extruder with L/D = 36 and
diameter 60 mm with 9 heating zones.
The extrusion parameters are as follows:
RPM: 140
Flow rate: 40 kg I hour
Thermal profile 60-140-175-1KO\4-155\2T
Screw diameter ratio (max. diam. / min. diam.) 1.31-1.35
Ratio between transport and mixing zones: 2:1
Degassing in zone 8 out of 10
Final water content of the granule equal to 0.8%
The compositions of Table 1 were filmed on a 40 mm Ghioldi machine, die yap = 1 mm, flow
rate 20 kg/h to obtain film with a thickness of 20 u,m.
The 20 um films were then subjected to mechanical characterization according to the standard
ASTM D882 (traction at 23°C and 55%; Relative humidity and Vo = 50 mm7min).
The results arc indicated in Tabic 2 below.

The granules of the compositions according to examples I and 2 were fractured, subjected to acid etching to eliminate the starch particles, then a micro photography was performed with x4000 magnification under the Scanning Electron Microscope (SEM). The microphotographs relating to Example 1 and 2 arc shown in Figure 1 and 2, respectively. They show:
- a dimension of the starch nanoparticles with a numeric mean of less than 0.25 urn;
- a distribution of the starch nanoparticles such as:

- dimension of 80% of them is less than 0.2 urn;
- the area of such 80% is greater than 45% with respect to the total area of the starch particles.
Example 3 (comparison)
The example n°5 of the patent EP 0 965 615 Al was repeated.
The composition obtained according to said example was filmed with a thickness of 20 um.
The table below (Table 3) shows the mechanical properties of the resulting film.

The film of the composition according to example 3 was fractured, subjected to acid etching to eliminate the starch particles and microphotography was performed with x4000 magnification under the Scanning Electron Microscope (SEM). The microphotographs relating to Example 3 is shown in Figure 3. The microphotograph shows:
- a dimension of the starch nanoparticles with a numeric mean of 0.43 urn;
- a distribution of the starch nanoparticles such as:
- dimension of 80% of them is less than or equal to 0.56 urn;

CLAIMS Multiphase biodegradable compositions comprising at least two phases:
(a) a continuous phase composed of a matrix of at least one tough hydrophobic polymer incompatible with starch, said polymer being selected from the class of polyesters from diacid-diol;
(b) a homogeneously dispersed nanoparticulate starch phase;
wherein a film of a thickness of 20 um obtained from said compositions and tested
according to ASTM D822 is characterized by a K factor greater than 28 and by numeric
mean dimensions of the particles of said dispersed starch phase (b) of less than 0.25 um>
wherein the K factor is defined by the following formula
K = (Breaking load) x (Young's Modulus) x (Breaking energy)/1,000,000
With Breaking load and Young's Modulus expressed in MPa and Breaking energy in KJ/m2.
Multiphase biodegradable compositions according to claim 1, characterized by K factor
greater than 30.
Multiphase biodegradable compositions according to claim 1, characterized by K factor
greater than 33.
Multiphase biodegradable compositions according to claim 1, characterized by a dispersed
starch phase with in particles having mean dimensions of less than 0.20 urn
Multiphase biodegradable compositions according to claim 1, characterized by a dispersed
starch phase with in particles having mean dimensions of less than 0.18 um.
Multiphase biodegradable compositions according to claim 1, characterized by a distribution
of the starch
nanopaitides is as follows:
- dimension of 80% of the starch particles is less than 0.35 um;
- the area of such 80% starch particles is greater than 45% with respect to the total area of the starch particles.
Multiphase biodegradable ompositions according to claim 1, characterized in that:
(a) said matrix comprises at least one tough thermoplastic polymer incompatible with starch in the continuous phase in an amount from 55 to 95%;
(b) said dispersed starch phase comprises at least one destructurized nanoparticulate starch in an amount from 5 to 45%.
Multiphase biodegradable compositions according to claim 1, characterized in that: (a) said matrix comprises at least one tough thermoplastic polymer incompatible with starch in the continuous phase in an amount from 58 to 90%;

(b) said dispersed starch phase comprises at least one destructurized nanoparticulate
starch in an amount from 10 to 42%.
9- Multiphase biodegradable compositions according to claim 1, characterized in that:
(a) said matrix comprises at least one tough thermoplastic polymer incompatible with starch in the continuous phase in an amount from 60 to 85%;
(b) said dispersed starch phase comprises at least one destructurized nanoparticulate starch in an amount from 15 to 40%.
10. Multiphase biodegradable compositions according to claim 1, characterized in that:
(a) said matrix comprises at least one tough thermoplastic polymer incompatible with starch in the continuous phase in an amount from 62 !o 80%;
(b) said dispersed starch phase comprises at least one destructurized nanoparticulate starch in an amount from 20 to 38%.

11. Multiphase biodegradable compositions according to claim 1, wherein said tough thermoplastic polymer is characterized by Modulus of leas than 200 MPa.
12. Multiphase biodegradable compositions according to claim 1, characterized by an ultimate elongation greater than 500%.
13. Multiphase biodegradable compositions according to claim 1, characterized in that said polyester comprises a diacid moiety derived from a diacid selected from the group consisting of the following aliphatic diacids: succinic, ndipic, azelaic, sebacic, undecandioic, dodecandioic, brassylic acid or mixtures thereof.
14. Multiphase biodegradable compositions according to claim 1, characterized in that said polyester comprises a diacid moiety derived from a at least one aromatic diacid.
15. Multiphase biodegradable compositions according to claim 14, characterized in that said diacid moiety is selected from the group consisting of dicarboxylic compounds of the phtalic-acid type and their esters,
\6. Multiphase biodegradable compositions as claimed in claim 15, characterized in that said dicarboxylic compound of the phtalic-acid type is a compound of terephthalic acid,
17. Multiphase biodegradable compositions according to claim 16, characterized in that said terephthalic acid is present in an amount from 49 to 66 mol % with respect to the total amount of the acid components.
18. Multiphase biodegradable compositions according to claim 16, characterized in that said
terephthalic acid is present in an amount from 49.5 to 63 mol% with respect to the total
amount of the acid components,
19- Multiphase biodegradable compositions according to claim 16, characterized in that said

terephthalic acid is present in an amount from 50 to 61 mol% with respect to the total amount of the acid components.
20. Multiphase biodegradable compositions according to claim 1, characterized in that said matrix of at least one tough hydrophobic polymer comprises additives selected ftom polycarbodiimides, polyepoxy resins, peroxides or oxazolines.
21. Multiphase biodegradable compositions as claimed in the previous claim, wherein said additives arc polyepoxy resins.
22. Multiphase biodegradable compositions as claimed in the previous claim, wherein polyepoxy resins are bisphenol A diglycidyl ether.
23. Multiphase biodegradable compositions according to claim i, characterized in that said dispersed starch phase (b) is made of native starch.
24. Multiphase biodegradable compositions as claimed in the previous claim wherein native starch is selected from the group consiting of potato, com, tapioca, pea, rice, wheat, hrgh-amylose starch - preferably containing more than 30% by weight of amylose - and waxy starch.
25. Multiphase biodegradable compositions as claimed in the previous claim, wherein native starch is destructurized native starch.
26. Multiphase biodegradable compositions as claimed in the previous claim, wherein the destructurized native starch is potato and com starch.
27. Multiphase biodegradable compositions as claimed in the previous claim, wherein the destructurized native starch is potato starch.
28. Multiphase biodegradable compositions according to claim 1, characterized in that said dispersed starch phase
(b) comprises physically and chemically modified starches.
29. Multiphase biodegradable compositions according to claim 28, characterized in that said physically and chemically modified starches are selected from the group consisting of: ethoxylated starches, oxypropylated starches, starch acetates, starch butyrate, starch propionates, with a substitution degree comprised within the range of from 0.1 to 2, cationic starches, oxidized starches, cross-linked starches, gelled starches.
30. Multiphase biodegradable compositions according to claim 1, characterized in that said further dispersed phase comprises apolyhydroxyalkanoate.
31. Multiphase biodegradable compositions as claimed in the previous claim, wherein said polyhydroxyalkanoate is a polymer or copolymer of polylactic acid with molecular weight Mw greater than 70,000 and with a modulus greater than 1,500 MPa.

32. Multiphase biodegradable compositions according to claim 1, characterized in that in the formation phase of the multiphase structure, at least one plastici^er for the starch is present.
33. Multiphase biodegradable compositions according to claim 1, characterized by containing plasticizers in quantities ofless than 10% in relation to the stun of (a) + (b).
34. Multiphase biodegradable compositions as claimed in the previous claim, wherein the plaslicizer is water or glycerol, or mixtures of both.
35. Multiphase biodegradable compositions as claimed in the previous claim, wherein the plasticizer is the water contained in the native starch.
36. Multiphase biodegradable compositions according to claim 1, characterized in that said in the formation phase of said compositions, additives other than plasticizers are added.
37. Multiphase biodegradable compositions as claimed in the previous claim wherein said additives are selected from antioxidants, UV stabilizers, heat and hydrolysis stabilizers, chain extenders, flame retardants, slow release agents, inorganic and organic fillers, such as natural fibres, antistatic agents, welting agents, colorants, lubricants or compatibilizing agents between the various phases.
38. Multiphase biodegradable compositions as claimed in the previous claim wherein hydrolysis stabilizers are carbodiimides and epoxy resins.
39. Multiphase biodegradable compositions as claimed in the previous claim wherein carbodiimides are aliphatic carbodiimides.
40. Multiphase biodegradable compositions as claimed in claim 38 wherein epoxy resins^are epoxidized polymethacrylates,
41. Multiphase biodegradable compositions as claimed in the previous claim wherein epoxidized polymethacrylates are of the glycidyl type.
42. Multiphase biodegradable compositions as claimed in the previous claim wherein epoxidized polyinethacrylate of the glycidyl type is a poly epoxy propyl methacrylate.
43. Multiphase biodegradable compositions according to claim 1, obtained by processing the components thereof in an extruder or other machine capable of providing temperature and shear conditions that allow a reduction of the dimensions of the particles of said dispersed starch phase (b) to less than 0,25 urn,
44. Film produced with multiphase biodegradable compositions according to claim 1.
45. Bags or sacks, extruded or thermoforraed, laminated with paper, aluminium, plastic and bioplastics, multiperforated produced with film as claimed in the previous claim.
46. Film according to claim 44 for food packaging, stretchable, heat-shrinkable film, film for adhesive tape, for disposable nappy tapes and for decorative coloured tapes, film for

covering packs of meats, cheese and other food items and yoghurt pots, film for silage.
47. Use of bags according to the claim 45 for carrying goods, for food packaging, as breathable bags for fruit and vegetables, bags for bread and other food products.
48. Textiles and non-woven fabric for clothing, coextruded fibers and spun bonded, hygiene and industrial products, including fishing nets or nets for fruit and vegetables produced with the substantially water insoluble biodegradable multiphase compositions as claimed in claim 1,

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Patent Number

278523

Indian Patent Application Number

2230/CHENP/2009

PG Journal Number

54/2016

Publication Date

30-Dec-2016

Grant Date

23-Dec-2016

Date of Filing

22-Apr-2009

Name of Patentee

NOVAMONT S.P.A

Applicant Address

Via G. Fauser 8,1-28100 Novara

Inventors:

#	Inventor's Name	Inventor's Address
1	BASTIOLI, CATIA,	VIA DELLA NOCE, 63, I-28100,
2	FLORIDI,GIOVANNI,	VIA TREDICI MARTIRI 8, I-28100 NOVARA,
3	DEL TREDICI, GIANFRANCO,	VIA SEMPIONE, 31, I-21018 SETSTO CALENDE

PCT International Classification Number

C08L 67/02

PCT International Application Number

PCT/EP07/60230

PCT International Filing date

2007-09-26

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	MI2006A001844	2006-09-27	Italy