Title of Invention

TOUGH-ELASTIC MATERIAL BASED ON STARCH

Abstract

The invention relates to a tough-elastic material based on starch, which on the one hand has high impact toughness at low humidities, and on the other hand still has a high modulus of elasticity at high humidities and has a high elongation capacity in a broad range of humidities and on account of its property profile is suited to use as moulded elements such as for example for foils, films, fibres, injection-moulded articles, in particular as edible film and for the packaging of active ingredients, chemicals, aromas and perfumes as well as high-quality substitution of gelatine in the area of soft and hard capsules. The tough-elastic material can be obtained transparent and adjusted such that it dissolves on swelling in water or respectively disintegrates or remains intact.

Full Text

FORM 2 THE PATENT ACT 1970 (39 of 1970) & The Patents Rules, 2003 PROVISIONAL / COMPLETE SPECIFICATION (See Section 10, and rule 13) 1. TITLE OF INVENTION VISCOELASTIC MATERIAL 2. APPLICANT (S) a) Name : INNOGEL AG b) Nationality : SWISS Company c) Address : BOSCH 71, CH-6331 HUNENBERG, SWITZERLAND 3. PREAMBLE TO THE DESCRIPTION The following specification particularly describes the invention and the manner in which it is to be performed : - GRANTED 7-5-2007 ORIGINAL 657/MUMNP/2004 TOUGH-ELASTIC MATERIAL The invention relates to a tough-elastic material based on starch, which on the one hand has high impact toughness at low humidities, and on the other hand still has high modulus of elasticity at high humidities and has high elongation capacity in a wide range of humidities. Prior art Different tests were undertaken to obtain a useful material based on starch, based almost exclusively on softened thermoplastic starch (TPS). Polyols are typically used as softeners. In the case of TPS the starch is almost completely in amorphous form. The properties of amorphous polymers are determined predominantly by the brittle temperature Tg. Below Tg the state is vitreous, hard and brittle, and above Tg soft. The difference between both these states is particularly outstanding with TPS. Since starch macromolecules are relatively stiff and rigid, large proportions of softener are required. Below Tg TPS is extremely brittle and in particular very sensitive to a high stress rate, and above Tg TPS more and more takes on the character of a sticky high-viscosity liquid with increasing temperature. Because starch and its softeners are therefore strongly hydrophilic, TPS absorbs water from the atmosphere and the sensitivity of TPS to humidity RH is a further problem, which stands in the way of using TPS in practice. The correlation between RH and water content of a material is described by its sorption curve. Through water uptake Tg is thrust down to lower temperatures, so that at a constant temperature with increasing water content a comparable variation of the property profile is obtained, such as with increase in temperature, i.e. at. lower RH TPS is hard and brittle, and soft at high RH. As a result of the sorption behaviour the material properties such as for example impact toughness K, strength om, modulus of elasticity, elongation capacity eb, oxygen permeability P02 and surface quality are very noticeably dependent on humidity, whereas ideally the most constant possible material properties are preferred. To date based on starch it has not been possible at low RH to obtain adequate toughness and at the same time to obtain adequate strength at high RH; for this starch had to be blended with synthetic substances. Examples of TPS with the abovementioned disadvantages are specified in patent documents WO 94/28029, US 5362777, US 5382611, US 5427614, WO 94/04600, US 5415827 and US 5462980. Soft and hard capsules are a proven form for pharmaceuticals and nutritionals. Once the capsules are ingested the fastest possible release of the capsule contents should generally take place. Accordingly the materials, with which soft and hard capsules are manufactured, or which are potentially considered for this, are at least hydrophilic, generally also water-soluble, such as for example gelatine, which is used to produce more than 95% of the current capsules. The above problem of the material properties varying strongly with RH also applies to these fields of application. Gelatine for example was the previous standard solution in the region of soft and hard capsules, containing 25 - 50% glycerine as softener, has at RH of 23% 4.5% water, while the water content at RH of around 85% is above 30%. Since water is a very efficient softener, the properties of softened gelatine are thus highly dependent on humidity. Their modulus of elasticity for example, a measurement for stiffness and dimensional stability, is round 8 5% RH by a factor of around 600 times less than at 23% RH, i.e. at low humidity the material is comparatively stiff and hard, whereas at high RH it becomes very soft and dimensional stability suffers. Further important material properties vary as a function of RH likewise by orders of magnitude. The increase of stickiness and oxygen permeability P02 which at an increase of RH of 0% to 75% is a factor of approximately 100, is particularly problematic. For these reasons the use of gelatine capsules in particular in damp climates is problematic and expensive packing is required to protect the capsules from moisture. The pronounced dependence of the properties of hydrophilic capsule materials on humidity is a basic problem. An ideal solution in the area of hard and soft capsules with constant properties in a wide range of current humidities is a priori not possible. In practice there must always be a compromise between the properties at low and at high humidities, i.e. tough behaviour at low RH signifies a reduced dimensional stability at high RH and vice versa good dimensional stability at high RH means a loss in toughness to brittle properties at low RH. With gelatine-based capsules at least one acceptable compromise could be found. However since the gelatine obtained from slaughterhouse waste as a result of the BSE problem and in the course of the trend to vegetarian products is being increasingly declined by consumers, the quest was made for new solutions based on. raw materials of plant origin. In patent document WO 01/37817 a soft capsule based on thermoplastic starch (TPS) with high softener content is described. It has however the considerable disadvantage of having noticeable brittleness at low humidities, so that in a dry environment the TPS soft capsule already breaks and splinters at minimal stress with a vitreous break. At high RH the TPS soft capsule becomes very soft and sticky and loses its dimensional stability. The TPS soft capsule is therefore clearly the basis of the gelatine soft capsule and the use of the TPS soft capsule is feasible only at average RH. In the case of hard capsules, where the requirements for toughness are even greater as a result of the stress of the capsules in automatic high-speed filling machines, capsules based on TPS could not previously be made. In patent documents US 6214376 and US 6340473 soft capsules based on carrageenan and starch are described. The disadvantage of this solution is that soft capsules at average RH are already too soft and thus insufficiently dimensionally stable. At higher RH this behaviour is even more noticeable. Further disadvantages are the high oxygen permeability, the high raw material costs of carrageenan, clearly more expensive than gelatine, as well as the suspicion of cancerogenity of carrageenan. These examples clarify the underlying problem of the material properties varying noticeably with humidity in capsules, which apply for other applications of hydrophilic materials in the area of foils, films, fibres, cast articles etc.. Problem The object of the present invention based on starch is to provide a material having at least the following properties: 1. dimensional stability at RH in the range of 10 -90%, in particular at high RH 2. toughness at RH in the range of 10 - 90%, in particular at low RH 3. long-term stability or respectively resistance to aging 4. gas barrier properties: in particular low oxygen permeability 5. optical properties: transparency and achromatism, but colourable and printable 6. surface properties: no stickiness 7. biodegradable, in particular edible. If required, the following properties should be obtained: 8. elasticity of at least 100% in the range of 25 -60% RH 9. weldability, in particular at low temperatures below 40°C 10. swelling capacity, in particular solubility or respectively disintegration in water 11. solubility or respectively disintegration in the stomach (37°C), in particular release of a substance according to pharmacopoeia 12. raw materials available at least in food quality. The specified properties are not independent, partially even to a large extent mutually dependent, i.e. optimising a specific property has advantageous or disadvantageous consequences with respect to the other properties. Brief Description of the Invention As a solution to this task a physical structure was first sought, which can satisfy and preferably surpass the requirements. It was found that the requirements can be fulfilled by the combination of the following elements. 1. The basis of the tough-elastic material is given by a hydrophilic phase, which is water-soluble or swells and decomposes in water. This phase is preferably amorphous or if it is in partial crystalline state, the crystallites or ordered regions are 2. Amorphous phases behave at temperatures >> Tg or respectively at RH » RHZ in the manner of highly viscous liquids, also when their viscosity is so high that they appear as solid bodies. Since water is more efficient compared to other softeners in hydrophilic systems with respect to the softening effect by factors, this leads to the fact that the amorphous phase becomes continuously softer with increasing humidity, loses stability and finally deliquesces. Since an amorphous phase cannot therefore meet requirements 1, 2, 6, 8 at high RH, reinforcement was sought. It was found that a network can be built for this purpose, which has less dependency of the properties on the RH, since flowing at high RH as a result of cross-linking is not possible. This network interpenetrates the amorphous phase preferably and is linked to this phase. Since existing i.e. chemical networks are water-insoluble from the forming of covalent bonds and also do not disintegrate after swelling, according to the present invention ea network is introduced whereof the linking points are thermoreversible and/or can be dissolved again via a solvent, in particular by addition of water or respectively gastric juice at 37°C, or respectively become mechanically unstable. In addition, networks which swell sufficiently are also suitable, so that in the swollen state they disintegrate under the effect of minimal stress. This is possible in particular with thin films. If the network points are formed at least partially by ordered areas such as crystallites, these areas are 3. Through water absorption from the atmosphere a network is influenced slightly only with respect to mechanical properties. Whereas for example the modulus of elasticity of a hydrophilic amorphous phase can vary by a factor of around lOOOin the range of the usual humidities, the modulus of elasticity of the network varies by a factor of the amorphous phase. This even made it possible to obtain virtually constant moduli of elasticity in the range of humidities of approximately 30 - 70%. The unsatisfactory properties of the amorphous phase at high humidities could be compensated by a network with adequate network density and at the same time toughness could be obtained at low humidities and strength at high humidities. 4. However, since networks are disadvantageous with respect to water solubility, according to the present invention either the network density is set so low that the network disintegrates after swelling in water as a result of minimal strength under minimal stress (which is the case in particular with thin films) , or the network points were preferably adjusted by very small crystallites, which are dissolved in excess by water. 5. The structure, after having been adjusted, remains stable under alternating conditions of humidity and temperature in an unusually broad range. This can be achieved by formulation and manufacturing conditions, whereby the network density is adjusted to the required volume. The specified elements basically point out the way to different practicable solutions based on different raw materials and formulations. The salient points are the balance between amorphous phase and network, and the parameter of the network, which on the one hand is sufficiently strong to ensure the mechanical properties of the material under variable conditions and on the other hand does not disable the solubility or disintegration of the capsules in water or respectively in gastric juice. To bring these requirements together in harmony is a central aspect of the present invention, whereas networks corresponding to the prior art do not meet this requirement. Previous networks based on starch for example are practically completely insoluble in water are stable against disintegration, are known to be opaque to full intransparency, not weldable, also show only minimal elasticities in the region of typically The inventive tough-elastic material based on starch has at low relative humidity RHZ a transition from brittle to tough behaviour so that in the range of usual humidities it is in the tough state. At room temperature this characteristic value is RHZ in % at 0.1, preferably > 0.5, more preferably > 1.0, most preferably > 3, and in each case Preferably the inventive tough-elastic material has the following bandwidth with respect to impact toughness K in mJ/mm2 and,with respect to the modulus of elasticity in MPa: a) at RH of around 11% is K > 10, preferably > 15, more preferably > 30, most preferably > 50 and in each case b) at RH of around 85% is E > 0.1, preferably > 0.5, more preferably > 1.0, most preferably > 3, and in each case c) at RH of around 75% is E > 0.5, preferably > 1, more preferably > 5, most preferably > 10 and in each case The inventive tough-elastic material further preferably has the following bandwidth with respect to these Properties: a) at RH of around 23% is K > 15, preferably > 30, more preferably >50, most preferably > 100 and in each case b) at RH of around 85% is E > 0.2, preferably > 1.0, more preferably > 2.0, most preferably > 5 and in each case c) at RH of around 75% is E > 1.0, preferably > 2.0, more preferably > 10, most preferably > 20 and in each case . The inventive tough-elastic material further preferably has the following bandwidth with respect to these properties: a) at RH of around 33% is K > 20, preferably > 50, more preferably > 100, most preferably > 200 and in each case b) at RH of around 85% is E > 0.2, preferably > 1.0, more preferably > 2.0, most preferably > 5.0 and in each case c) at RH of around 75% is E > 1.0, preferably > 2.0, more preferably > 10, most preferably > 20 and in each case The inventive tough-elastic material preferably also has a tough break in the impact test, i.e. elongation at break sk in % discloses the following areas as a function of humidity: a) at RH of around 43% is sk > 5, preferably > 10, more preferably > 20, most preferably > 30 and in each case b) at RH of around 33% is sk > 3, preferably > 7, more preferably > 14, most preferably > 20 and in each case c) at RH of around 23% is sk > 2, preferably > 5, more preferably > 10, most preferably > 15 and in each case The inventive tough-elastic material further has as a function of humidity preferably a strength at 10% elongation Om, 10% in MPa in the following areas: a) at RH of around 85% is Om,i0% > 0.2, preferably > 0.4, more preferably > 1, most preferably > 3 and in each case b) at RH of around 75% is 0m,io% > 0.4, preferably > 0.8, more preferably > 1.5, most preferably > 5 and in each case The inventive tough-elastic material further preferably has the following properties with respect to elongation at break sb in %: a) the maximum of elongation at break sb as a function of RH is > 50, preferably > 100, more preferably > 200, most preferably > 300 and in each case b) elongation at break sb RH at RH of around 75% is > 20, preferably > 50, more preferably > 75, most preferably > 100 and in each case The inventive tough-elastic material preferably also an elastic limit in the range of RH of around 20 - 50% in the tensile test. A particularly advantageous property of the inventive tough-elastic material is that with respect to the modulus of elasticity and tensile strength at 10% elongation can be obtained as a function of RH with a quasiplateau, whereby in particular: a) the factor FE(23 - 85) of the variation of the modulus of elasticity at RT in the range of 23 - 85% RH is most preferably 1; or b) the factor FE(43-75) of the variation of the modulus of elasticity at RT in the range of 43 - 75% RH is preferably 1; and c) the factor Fa1o%(23 - 85) of the variation of the tensile strength at 10% elongation at RT in the range of 23 - 85% RH is 1; or d) the factor Fa10%(43 - 75, of the variation of the tensile strength at 10% elongation at RT in the range of 43 - 75% RH is 1. The inventive material can thus be used both at high RH (e.g. summer) without major loss of dimensional stability and at low RH (e.g. winter) without embrittlement. This is important e.g. when the material is used as material for a soft capsule for pharmaceuticals and nutraceuticals. Further particularly advantageous properties of the inventive tough-elastic material comprise at least one of the following properties being appropriate: a) the ordered areas of the material, which form the cross-linking points of the network, exhibit dimensions in nm b) the material is transparent at RH 90%. c) the material is not sticky in the range of RH at RH most preferably d) the material swells in water or respectively gastric juice and dissolves or respectively disintegrates with the slightest motion of these media, in particular at temperatures in °C preferably preferably Another particularly advantageous property of the inventive tough-elastic material is the good barrier effect to oxygen, whereby the permeability coefficient P02 of oxygen in [cm3mm/(m2) 2 4h] at RT is in the following ranges: a) at 0% RH is P02 b) at 50% RH is P02 c) at 75% RH is P02 Detailed Description of the Invention Conversion of the selected structure for different uses is based on the following elements of the solution: Basis and Present Starches For the base a present starch (PS) is selected. Basically this can be' any starch of any origin or a combination of such starches. Yet many starches form no homogeneous amorphous structure. In particular starches containing amylose tend to retrogradation, resulting in an ordered area, often with dimensions > 500nm. On the one hand the transparency is thereby impaired (opacity), and on the other hand retrograde starches exhibit restricted solution or disintegration behaviour. Since water solubility can additionally be aggravated by introducing a network, the best possible solution or disintegration behaviour of the base or respectively of the amorphous phase is a substantial prerequisite. Retrogradation is primarily the consequence of the amylose portion of starches, whereby the amylose at least partially crystallises. For this reason PS or mixtures of PS with an amylose content of With respect to purity starches originating from roots and bulbs or waxy starches are likewise preferred, in particular tapioca starch, since their protein and lipid contents are lower compared to non-waxy wheat starches, which is i.a. also an advantage for transparency and clarity. The disadvantage of wheat starches and potato starches, in particular maize starch, is that different genetically modified variants of these starches are added on and purity with respect to GMO proportions is problematic a priori. Therefore from this viewpoint starches are preferred, whereof no GMO variants are added on, for example sago or root starches, in particular tapioca starches. With respect to technological suitability however genetically modified starches are also considered as PS. Of particular interest also are dextrins, in particular pyrodextrins such as white dextrins, yellow or respectively canary dextrins, modified dextrins, co-dextrins or British gums. They exhibit good film development properties and as a result of their irregular structure and the high degree of branching Qb of typically > 0.05 they are partially to practically fully stable with respect to retrogradation and thus highly water-soluble, as well as being long-term stable, i.e. resistant to aging. Plus, the use of dextrins has a positive effect on the quality of the weld joint of soft capsules, since they have good adhesive properties. Dextrins with low to average degrees of converting can be used as sole PS or can be sued together with other PS, while dextrins with high degrees of conversion are preferably used together with other PS. With regard to optical properties white dextrins are preferred. Apart from amylose amylopectin can also retrograde, though to a clearly lesser extent and on a clearly larger time scale. The extent of the retrogradation of amylopectin and the stability of retrograded

Documents:

00657-mumnp-2004 abstract (7-5-2007).doc

00657-mumnp-2004 form 2 (granted) - (7-5-2007).doc

00657-mumnp-2004-abstract(granted)-(07-05-2007).pdf

00657-mumnp-2004-cancelled pages (07-05-2007).pdf

00657-mumnp-2004-claims(granted)-(07-05-2007).pdf

00657-mumnp-2004-claims(granted)-(7-5-2007).doc

00657-mumnp-2004-correspondence (07-05-2007).pdf

00657-mumnp-2004-correspondence(ipo)- (09-10-2006).pdf

00657-mumnp-2004-drawing(24-11-2004).pdf

00657-mumnp-2004-form 1(07-05-2007).pdf

00657-mumnp-2004-form 13(07-05-2007).pdf

00657-mumnp-2004-form 19(24-11-2004).pdf

00657-mumnp-2004-form 1a(17-11-2004).pdf

00657-mumnp-2004-form 2(granted)-(07-05-2007).pdf

00657-mumnp-2004-form 3(07-05-2007).pdf

00657-mumnp-2004-form 3(17-11-2004).pdf

00657-mumnp-2004-form 5(07-05-2007).pdf

00657-mumnp-2004-form 5(17-11-2004).pdf

00657-mumnp-2004-power of attorney (07-11-2004).pdf

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