EP1608686A1 - Viscoelastic material - Google Patents

Description

 Tough elastic material

The invention relates to a tough elastic material based on starch, which on the one hand has a high impact strength at low atmospheric humidities, on the other hand still has a high modulus of elasticity at high atmospheric humidities and has a high elasticity in a wide range of atmospheric humidities

State of the art

Various attempts have been made to obtain a usable material on the basis of starch, almost entirely based on plasticized thermoplastic starch (TPS). Polyols are typically used as plasticizers. The strength of TPS is almost entirely in amorphous form. The properties of amorphous polymers are largely determined by the glass transition temperature Tg. Below Tg the condition is glassy, hard and brittle, above Tg it is soft. The difference between these two states is particularly pronounced in TPS. Since starch macromolecules are relatively rigid and rigid, high levels of plasticizer are required. Below Tg, TPS is extremely brittle and in particular very sensitive to high stress rates, above Tg TPS takes on the character of a sticky, highly viscous liquid with increasing temperature. Since starch and its plasticizers are also highly hydrophilic, TPS absorbs water from the atmosphere and the sensitivity of TRS to the air humidity RF is another problem that stands in the way of the use of TPS in practice. The relationship between RF and water content of a material is described by its sorption curve. By taking up water, Tg is shifted to lower temperatures, so that at constant temperature with increasing water content a property profile is obtained which is comparable to the increase in temperature, ie at low RF TPS is hard and brittle, at high RF soft. As a result of the sorption behavior, the material properties such as impact strength K, strength σ _m , modulus of elasticity E, elasticity εt, oxygen permeability P ₀₂ and surface quality are very strongly dependent on the air humidity, while ideally constant material properties are desirable. So far it was based on Starch not possible to obtain sufficient toughness at low RF and at the same time to obtain sufficient strength at high RF. To do this, starch had to be blended with synthetic plastics. Examples of TPS with the disadvantages mentioned are listed in the patents WO 94/28029, US 5362777, US 538261 1, US 5427614, WO 94/04600, US 5415827 and US 5462980.

Soft and hard capsules are a proven dosage form for pharmaceuticals and nutritional products. After taking the capsules, the capsule contents should generally be released as quickly as possible. Therefore, the materials with which soft and hard capsules are produced, or which are potentially suitable for this purpose, are at least hydrophilic, generally also water-soluble, such as gelatin, which is used to produce significantly more than 95% of today's capsules. Thus, the problem of the material properties that vary greatly with the RF also applies to these fields of application. Gelatin or The previous standard solution in the field of soft and hard capsules, containing 25 - 50% glycerin as plasticizer, has a water content of around 23% and a water content of around 85%, while the water content of around 85% is above 30%. Da ^'Water is a very efficient plasticizers, the properties of plasticized gelatin are so heavily dependent on humidity. Their modulus of elasticity, for example, a measure of rigidity and dimensional stability, is around 85% RH less by a factor of around 600 than at 23% RH, i.e. the material is comparatively stiff and hard at low air humidity, while it is hard at high humidity RF becomes very soft and the shape stability suffers. Other important material properties also vary in order of magnitude in the function of the RF. The increase in stickiness and oxygen permeability P0 ₂ is particularly problematic, which is a factor of about 100 when the RF increases from 0% to 75%. For the above reasons, the use of _gelatin capsules, particularly in humid climates is problematic and expensive packaging is necessary in order to protect the capsules from the moisture.

The pronounced dependence of the properties of hydrophilic capsule materials on the air humidity is a fundamental problem. An ideal solution in the field of hard and soft capsules with constant properties in a wide range of common air humidities is not possible a priori. In practice, a compromise must always be sought between the properties at low and high air humidities, ie tough behavior at low RF means reduced dimensional stability at high RF and, conversely, good shape stability at high RF means a loss of ability to brittle properties at low RF. With capsules based on gelatin, at least an acceptable compromise could be found. However, after the gelatin obtained from slaughterhouse waste was increasingly rejected by consumers due to the BSE problem and in the course of the trend towards vegetarian products, new solutions based on raw materials of plant origin were sought. Patent specification WO 01/37817 describes a soft capsule based on thermoplastic starch (TPS) with a high plasticizer content. However, it has the serious disadvantage that it has a pronounced brittleness at low atmospheric humidities, so that the TPS soft capsule breaks and splinters in a dry environment with a glass-like fracture even under low stress. At high RF, the TPS soft capsule becomes very soft and sticky and loses its shape stability. The TPS soft capsule is therefore clearly inferior to the gelatin soft capsule and the use of the TPS soft capsule is only possible with medium RF. Capsules based on TPS have so far not been feasible in the hard capsule area, where the requirements regarding toughness due to the stress on the capsules in high-speed filling machines are even greater. In the patents US 6214376 and US 6340473 soft capsules based on carrageenan and starch are described. The disadvantage of this solution is that the soft capsules are too soft and therefore not dimensionally stable even at medium RF. This behavior is even more pronounced at higher RF. Other disadvantages are the high oxygen permeability, the high raw material costs of carrageenan, which is significantly more expensive than gelatin, and the suspected carcinogenicity of carrageenan. These examples illustrate the fundamental problem of the material properties in the capsule area, which vary markedly with the air humidity, which also applies to further applications of hydrophilic substances in the area of foils, films, fibers, injection molded articles, etc.

task

The object of the present invention is to provide a material on the basis of starch which has at least the following properties:

1. Dimensional stability with RF in the range 10 ~ 90%, especially with high RF

2. Toughness with RF in the range 10 - 90%, especially with low RF

3. Long-term stability or aging resistance

4. Gas barrier properties: especially low oxygen permeability 5. Optical properties: transparency and colorlessness, but dyeable and printable

6. Surface properties: no stickiness, 7. biodegradable, especially edible

If necessary, the following characteristics should also be obtained:

8. Elasticity of at least 100% in the range 25-60% RH

9. Weldability, especially at low temperatures below 40 ° C

10. Swellability, especially solubility or decay in water

11. Solubility or ' Decay in the stomach (37 ° C), especially release of an active ingredient according to the pharmacopoeia

12. Raw materials available at least in food quality

The properties listed are not independent of one another, in some cases even interdependent to a high degree, i.e. the optimization of a certain property has advantages or disadvantageous consequences in relation to the other properties.

Brief description of the invention

To solve the problem, the primary search was for a physical structure that can meet, preferably exceed, the requirements. It has the following characteristics:

1. The base is given by a hydrophilic phase, which is water-soluble or swells and disintegrates in water. This phase is preferably amorphous or if it is in the partially crystalline state, the crystallites or ordered areas are <500 nm. If they have larger dimensions, requirement 5 cannot be met. Amorphous phases generally exhibit brittle behavior at temperatures below the glass transition temperature Tg. Since the glass transition temperature varies for different properties and the tough-elastic material is used in a limited temperature range around room temperature, the dependence of this transition as a function of the RF is considered instead of the temperature dependence of the brittle-tough transition. Here, RF _{Z is} the RF, at RT the transition from brittle to tough behavior takes place. For the amorphous phase, RF _Z <33%, preferably <26%, more preferably <20%, most preferably <15% applies to a material that is tough at low RF. Consequently the amorphous phase shows a tough behavior at the given RF. This state is set using a suitable proportion of plasticizer. A polyol or a mixture of polyols with melting points that are as low as possible is preferably used as the plasticizer because their plasticizing effect is at a maximum and correspondingly small amounts have to be used. A high proportion of plasticizer increases the dependency of the properties on the RF.

2. At temperatures »Tg or at RF» RFz, amorphous phases behave like highly viscous liquids, even if their viscosity is so high that they appear as solid bodies. Since water is several times more efficient than other plasticizers in hydrophilic systems with regard to the softening effect, this means that the amorphous phase becomes softer with increasing air humidity, loses stability and finally flows.

Since an amorphous phase cannot meet requirements 1, 2, 6, 8 at high RF, the structure must be reinforced. For this purpose, a network is installed which has a lower dependency of the properties on the RF, since it is not possible to flow at high RF. This network preferably interpenetrates the amorphous phase and is coupled to this phase. Since covalent bonds, i.e. chemical networks are insoluble in water and do not disintegrate even after swelling, a network is introduced whose connection points are thermoreversible and / or can be dissolved again or become mechanically unstable by a solvent, in particular by adding water or gastric juice at 37 ° C. In addition, networks are also suitable that swell sufficiently so that they disintegrate in the swollen state under the action of low loads. This is particularly possible with thin films. If the network points are formed by at least partially ordered areas such as crystallites, these areas are <500 nm to ensure transparency.

3. Networks generally have good mechanical properties even at moderate network densities, ie high strengths and moduli of elasticity. A hydrophilic network is only slightly influenced in terms of mechanical properties by water absorption. For example, while the modulus of elasticity of a hydrophilic amorphous phase can vary by a factor of around 1000 in the range of normal air humidities, the modulus of elasticity of a hydrophilic network varies by a factor of <10, it can even in one wide range to be almost constant. The network density must therefore be set so that the contribution of the network to the modulus of elasticity and the strength at high water contents is at least comparable to the contribution of the amorphous phase. The contribution of the network in this area is preferably significantly greater than the contribution of the amorphous phase. In this case it is even possible to obtain almost constant moduli of elasticity in the range of around 30 - 70% humidity. A network with sufficient network density can compensate for the insufficient properties of the amorphous phase at high air humidities.

4. Since hydrophilic networks are problematic with regard to water solubility, either the network density must be set so low that the network disintegrates after swelling in water due to minimal strength under low stress (which is the case in particular with thin films), or the network points are preferably through very small crystallites formed, which can dissolve in excess of water. The stability of the crystallites, which decreases with the size of the crystallites, is used.

5. The structure, after being adjusted, remains stable under changing conditions of humidity and temperature, i.e. it is set to an equilibrium state. This can be achieved through the manufacturing conditions, the network density being set to the required level.

The elements listed basically point the way to various practical solutions based on different raw materials and recipes. The decisive points are the balance between amorphous phase and network, as well as the parameters of the network, which is strong enough on the one hand to ensure the mechanical properties of the material under changing conditions and on the other hand the solubility or the disintegration of the capsules in water or in Gastric juice not impossible. Bringing these requirements together is a central aspect of the present invention; prior art networks do not meet this requirement. Previous networks based on starch, for example, are practically completely insoluble in water and stable against decay, they are known to be opaque up to complete non-transparency, cannot be welded, and furthermore they only show low ductility in the range typically <50% and have a disadvantageous effect on toughness out. An essential key to solving the problems mentioned is the size of the ordered areas that constitute the network points. This size can be set through the structural parameters of the raw materials used, in particular through the suitable choice of the network-active chain length CLn.na of the starch molecules used.

Detailed description of the invention

The implementation of the selected structure for the different applications is based on the following elements of the solution:

Basis and existing strengths

An existing strength (VS) is selected for the base. Basically, this can be any strength of any origin or a combination of such strengths. However, many starches do not form a homogeneous amorphous structure. Starches containing amylose in particular tend to retrogradate, which creates orderly areas, often with dimensions> 500nm. This affects transparency on the one hand (opacity), on the other hand, retrogated etched starches have a limited dissolution or disintegration behavior. Since the solubility in water can be made more difficult by introducing a network, the best possible solution or disintegration behavior of the base or the amorphous phase is an essential prerequisite.

Retrogradation is primarily the result of the amylose portion of starches, with the amylose at least partially crystallizing. VS or mixtures of VS with an amylose content of <25%, in particular <22%, in particular <19% are therefore preferred, i.e. Rice or sago starches or starches derived from tubers and roots such as potatoes, yams, canna, arrowroot or tapioca. Waxy starches “with an amylose content of typically <1%, such as, for example, waxy maize, waxy rice, waxy millet, waxy barley, waxy potato or heterowaxy starches with an amylose content <20%, such as, for example, heterowaxy millet, are likewise preferred.

In terms of purity, starches derived from roots and tubers or waxy starches are also preferred, in particular tapioca starch, since their protein and lipid contents are lower in comparison with non-waxy cereal starches, which is also advantageous, inter alia, for transparency and clarity. Cereal starches and potato starches, in particular corn starch also have the disadvantage that various genetically modified variants of these starches are grown and purity is a priori problematic in terms of GMO proportions. Therefore starches are preferred from this point of view, of which no GMO variants are grown, for example sago or root starches, in particular tapioca starches. In terms of technological suitability, genetically modified starches can also be considered as VS.

Also of particular interest are dextrins, in particular pyrodextrins such as white dextrins, yellow or canary dextrins, modified dextrins, co-dextrins or British gums. They have good film-forming properties and, due to their irregular structure and the high degree of branching Qb of typically> 0.05, they are partially to practically completely stable with respect to retrogradation and therefore very readily water-soluble, and also long-term stable, i.e. aging. In addition, the use of dextrins has a positive effect on the quality of the weld seam of soft capsules, as they have good adhesive properties. Dextrins with low to medium degrees of conversion can be used as sole VS or together with other VS, while dextrins with high degrees of conversion are preferably used together with other VS. With regard to the optical properties, white dextrins are preferred.

In addition to amylose, amylopectin can also retrograde, but to a much lesser extent and on a much larger time scale. The extent of the retrogradation of amylopectin and the stability of the retrog etched amylopectin regions against solubility or decay in water is determined by the length of the A-side chains of amylopectin. In this context, the shortest possible A-side chains are advantageous. From this point of view, starches are preferred with CLw <18, preferably <16, more preferably <14, in particular <13, most preferably <12, i.e. For example, waxy starches, in particular waxy rice, tapioca starches or sago starches. On the other hand, the length of the A-side chains is also reflected in the more easily measurable properties of Blue Value (BV) and iodine affinity (IA), so that VS with amylopectin fractions of deep BV and deep IA are preferred.

Also preferred as VS are starches or mixtures of such starches, which are modified and counteracted by the following treatments or combinations of these treatments. have been stabilized via retrogradation, preference being given to using starches with a priori low tendency to retrogradation, such as, for example, tubers or root starches:

Oxidation (for example periodate oxidation, chromic acid oxidation, permanganate oxidation, nitrogen dioxide oxidation, hypochlorite oxidation: oxidized starches); Esterification (for example acetylated starches, phosphorylated starches (monoesters), starch sulfates, starch xanthate); Etherification (for example, hydroxyalkyl starches, especially hydroxypropyl or hydroxyethyl starches, methyl starches, allyl starches, triphenylmethyl starches, carboxymethyl starches, diethylaminoethyl starches); Cross-linking (e.g. diphosphate starches, diadipate starches); Graft reactions; Carbamate reactions (starch carbamates).

Starches with partially substituted hydroxyl groups show advantageous film-forming properties for use, high elongations, such as are required in particular for the production of films, and as a result of the substitution they are stabilized with respect to retrogradation, i.e. water soluble and transparent. These positive properties in the sense of the invention usually increase with the degree of substitution DS and the size of the substituted group. Starches with DS> 0.01, more preferably> 0.05, in particular> 0.10, most preferably> 0.15 are therefore preferred. The upper limit is given by regulatory provisions for food starches. From a technological point of view, however, modified starches with higher DS are also suitable and advantageous.

Examples of substituted starches of particular interest are hydroxypropylated or hydroxyethylated or acetylated or phosphorylated or oxidized root and tuber starches or waxy starches with maximum permissible degrees of substitution of around 0.20 for food starches.

Also of particular interest with regard to viscosity are VS, ie chemically cross-linked starches such as distarch phosphates, distarch adipates or inhibited starches (novation starches). Chemically crosslinked and simultaneously substituted starches are particularly preferred, with higher degrees of substitution also being preferred here. Suitable process measures, in particular by checking the shear forces, can ensure that at least part of the chemical crosslinking within the starch grain is retained in the end product. In this case, the amorphous phase is a two-phase system containing network fragments of the original starch granules, whereby E- The modulus and strength of the capsule in the problematic area can be positively influenced by high atmospheric humidity, while the water solubility is not significantly impaired. It should be emphasized that the discontinuous network fragments differ fundamentally from the physical networks essential for the solution. The required property profile cannot be achieved on the basis of the network fragments alone, but they can make a positive contribution in terms of an optimized solution. Another advantage of using substituted and chemically cross-linked starches is that a wide range of types with different degrees of substitution and cross-linking of these cheap commodity starches are commercially available in food quality. Examples are hydroxypropylated distarch phosphates, hydroxypropylated distarch adipates, acetylated distarch phosphates or acetylated distarch phosphates, which are based on starches of various origins such as corn, wheat, millet, rice, potato, tapioca et. are available.

Another group of starches of interest are hydrolyzed starches such as acid-hydrolyzed starches or enzymatically hydrolyzed starches, as well as ^" chemically modified hydrolyzed starches, in particular based on starches with amylose contents of <25%, provided that they have a reduced tendency to retrogradation, which is due to additional modification how oxidation or substitution is achieved.

Basically, VS with a low, reduced or disappearing tendency to retrogradation are preferred. VS with higher amylose contents such as cereal starches, pea starches or high amylose-containing maize starch can, however, be used if measures are taken to prevent or minimize the retrogradation, e.g. through process measures such as freezing of the amorphous state and / or heat treatment with a defined water content , in particular in the case of low water content, and / or chemical modification of the VS such as, for example, substitution of hydroxyl groups, and / or measures relating to the recipe, substances which inhibit retrogradation being admixed. By a combination of these measures, an amorphous state can on the one hand be achieved whereby water solubility and ^'decay is guaranteed or otherwise retrogradation can have the effect minimized by the formation of a limited, but defined network is still possible, whereby a balance between toughness at low humidity and sufficient strength and rigidity can be achieved in high humidity. In this case, it is possible to add an additional network, which is more network-compatible Starch (NS) is introduced, ie the required material properties can then be achieved on the basis of VS alone or a combination of VS. Usually, however, a combination of VS and NS is used, since the process engineering implementation and the control of the material properties (solubility, toughness, elongation, transparency, etc.) of such mixtures is easier.

The starches listed can be used both in native granular form (cooking starches) and physically modified (pregelatinized, cold water soluble, cold water swelling).

The explanations on the selection of the VS, whereby a specific VS or a combination of two or more VS can be considered, makes it clear that with regard to the origin and the type and degree of modification or modifications, a large number of different options with individual , whereby technological disadvantages are offset by the election of another recipe parameters and / or process measures can ^'advantages and disadvantages to choose from. It is therefore possible to select a starch or a combination of starches as VS, which not only meet the technological requirements, but also commercial aspects such as raw material prices and availability, as well as aspects relating to optimal process variants, purity or GMO-free, can be taken into account. Furthermore, it is also possible to choose an optimal solution with regard to the product properties for specific applications.

softener

With regard to plasticizers (WM), there is a wide range of known starch plasticizers to choose from, which have been described many times in the prior art (see, for example, WO 03/035026 A2 or WO 03/035044 A2). The polyols glycerol are mentioned here , Erythritol, xylitol, sorbitol, mannitol, galactitol, tagatose, lactitol, maltitol, maltulose, isomalt. These and other plasticizers can each be used alone or in various mixtures. It has been found that plasticizers particularly suitable for starch networks have melting points <100 ° C., preferably <70 ° C., more preferably <50 ° C., most preferably <30 ° C. Water is by far the most important plasticizer, around 2.5 times more effective than glycerin. Here is water but mostly not called plasticizers to distinguish water from other plasticizers.

Network and networkable strengths (NS)

Since it is not possible to obtain sufficient toughness at low RF on the basis of an amorphous phase alone and at the same time to achieve sufficient dimensional stability and strength at high RF, a defined network is introduced, which reinforces the structure. Networks which are coupled to the amorphous phase are preferably generated. This coupling ^'can be achieved at appropriate process conditions by an appropriate selection of NS and by coordinating with the NS VS.

Starches containing or consisting of amyloses or amylose-like starches are used as NS. A mixture of different NS types is also referred to as NS. It is pointed out that in certain cases, in particular in the case of SCP and SDP methods, VS and NS can be materially identical, since in principle every NS can also be used as VS. The difference between VS and NS is therefore not material in all cases, rather the terms must also be understood in connection with the process. NS is treated in such a way that its potential for forming networks is optimally released, whereas this does not have to be the case with VS.

The amyloses can be linear as well as branched and optionally modified. Examples of NS are amyloses from native starches, in particular amyloses obtained by fractionating starches with an amylose content> .23%, modified amyloses, in particular substituted amyloses or hydrolyzed amyloses, synthetic amyloses, cereal starches, pea starches, high amylose starches, in particular with an amylose content> 30 , preferably> 40, more preferably> 60, most preferably> 90, hydrolyzed starches, in particular hydrolyzed high amylose starches or sago starches, gelling dextrins, fluid starches, microcrystalline starches, starches from the field of fat replacers. In addition, NS can also have an intermediate fraction, such as those contained in starches containing high amylose and which can be obtained by fractionation. In terms of their structure and properties, the intermediate fraction lies between amylose and amylopectin. For amylose, the distinction between long chain amylose (LCA) with DPn> 100 and short chain amylose (SCA) with DPn <100 is common. Network-capable strengths can have LCA and / or SCA.

Short chain amylose (SCA)

Examples of SCA are amylodextrins, linear dextrins, nail dextrins, lintnerized starches, erythrodextrins or achrodextrins, which represent different names and subgroups of SCA.

SCA can be obtained, for example, by hydrolysis of LCA, LCA-amylopectin mixtures or amylopectin mixtures. SCA which is particularly suitable for advantageous networks is obtained, for example, by hydrolysis of starches originating from roots and tubers or from heterowaxy or waxy starches. The hydrolysis can be carried out chemically, such as, for example, acid hydrolysis and / or enzymatically, for example using amylases or combinations of amylases (alpha-amylase, beta-amylase, amyloglucosidase, isbamylase or pullulanase). Amylose-containing starches are obtained as SCA by combined acid / enzyme hydrolysis, and the two hydrolyses can be carried out simultaneously or in succession. Depending on this, different types of SCA can be obtained from the same strength. In addition, the characteristics of SCA are also influenced by the state of the native starch during hydrolysis, for example by the degree of swelling of the starch granules. Therefore a wide range of suitable SCA is available. Further types can be obtained by acid / enzyme hydrolysis or enzyme hydrolysis starting from waxy starches, SCA hydrolysates with DPn typically being obtained around 22, which are particularly suitable. Also of particular interest is SCA, which is formed during the process of processing the starches into the NSF and finally the starch network, e.g. through pullulanase.

Long chain amylose (LCA)

The amylose contained in native starch is usually LCA with DPn> 100. However, the degree of polymerization DPn of LCA can be reduced, for example, by acid hydrolysis and / or enzymatic hydrolysis and / or oxidation to values <100, so that appropriately modified native starches also have SCA can. Numerous processes for producing SCA, LCA and mixtures of SCA and LCA are described in the prior art. Both types of amylose are available on the one hand in pure form and are also present in different, optionally hydrolyzed, commercial starches in different proportions.

Advantageous networks

The structural requirements for coupling the network to the amorphous or predominantly amorphous phase are given by the chain lengths CLw (A-AP) of the A side chains of the amylopectin fraction and by the chain lengths of the amylose 'fraction. The chain lengths CLw (A-AP) of A-side chains of amylopectin for amylopectins from starches with an amylose content <30 are in the range of around 10-20, while high amylose starches have somewhat longer chain lengths CLw (A-AP). Amyloses, on the other hand, can also have much longer chain lengths CLw (AM). For long chain amyloses (LCA), chain lengths CL (LCA) are typically in the range from 100 to 1000, with root and tuber starches having significantly longer chain lengths than cereal starches. For short chain amyloses (SCA), the chain lengths CL (SCA) <100 and generally of about the same size as the degrees of polymerization DP (SCA), where CL (SCA) <DP (SCA). Since information on the weight average CLw is only rarely available for the various starches, the number average CLn of the chain length distribution and the number average DPn of the distribution of the degree of polymerization are used for a simplified discussion. In general, CLw is slightly larger than CLn, although the difference in A-side chains of amylopectin is only slight because they have a narrow distribution, while the difference in SCA is larger and can be very large in LCA.

The minimum chain length of amylose CLn (AM) or the minimum degree of polymerization of amylose DPn (AM) in order to use amylose to couple a network to the amorphous phase is approximately CLn (AM) - CLn (A-AP), ie around 10 - 20, - whereby advantageous couplings up to around CLn (AM) ~ 100 are possible. Above this value, networks can also arise which are not coupled to the amorphous phase, ie which consist predominantly of amylose. These networks have disadvantageous properties with regard to the requirements, for example opacity at higher RF, water insolubility, significantly reduced elongations at break and toughness compared to coupled networks. For this reason, SCA as NS or as a proportion of NS is suitable for the production of networks coupled to the amorphous phase, the stability of the crystallites forming the network points, ie their size, decreasing with decreasing CLn (AM) or DPn (AM) and the water solubility and the transparency of the substance increases.

Advantageous networks are obtained with proportions psc _A of SCA in% by weight dsb based on amylopectin and SCA in the range from 1-35, preferably 2-25, in particular 3-20, most preferably 4-14.

Furthermore, an advantageous coupling of the network with the amorphous phase is possible when LCA is used if its network-active chain length CLn, na (LCA) is in the range of the chain length of SCA, i.e. <100 is.

Irregularities can be introduced into the chain length CLn (AM) by chemical reactions, in particular by substitution of hydroxyl groups of the anhydroclucose monomer unit, by oxidation or crosslinking. In the case of a chemical reaction in the center of gravity of a segment characterized by its chain length CL, the network-active chain length is halved from CL to 1 / 2CL. It is therefore possible to obtain advantageous networks, for example by hydroxypropylation or acetylation, also on the basis of LCA. Advantageous degrees of substitution (DS) are in the range of approximately 0.01-0.50.

Advantageous networks are obtained with proportions P CA of modified LCA in% by weight dsb based on amylopectin and LCA in the range 1-70, preferably 2-50, in particular 3-40, more preferably 4-35, most preferably 5-30. In the case of high degrees of modification, the proportions of PLCA are higher than in the case of low degrees of modification.

Finally, advantageous networks based on LCA with CLn, na> 100 can be obtained if suitable conditions are created for this through process measures, such as shaping at comparatively low water contents or low temperatures and / or heat treatment with RF in the range 20-60% and / or addition of RHS, the (large-scale) association of amylose to amylose networks being suppressed and the (small-scale) association of amylose with A-side chains being favored by amylopectin. Activation and stabilization of the NS in the SCP and SDP procedure

To set a defined network, NS and possibly VS are activated and, in particular, stabilized before or during mixing with VS. The activation ensures that the amylose contained in NS is in an amorphous state, so that after mixing with VS a recombination can take place, which leads to a network. The stabilization makes it possible to influence the start of network formation and the type of network.

The higher the water content and the greater the shear forces during the plasticizing or dissolving process, the lower the temperatures required. Activation combined with stabilization of the NS is of particular importance. Stabilization is achieved by overheating the amylose to temperatures above the melting or dissolving process. In addition, foreign nucleating agents and / or methods for generating suitable germs can be used by supercooling the activated NS. With regard to activation, stabilization, nucleation, hypothermia and foreign nucleating agents, reference is made to the patent applications WO 03/035026 A2 and WO 03/035044 A2 for detailed information.

The temperature of the recombination of the amylose to the desired network can be adjusted to low temperatures by the stabilization. The higher the stabilization or overheating temperature, the lower the temperature the recombination or network formation takes place with the same water and plasticizer content. This is particularly important for the production of soft capsules, where the network should only arise after the capsules have been produced, because on the one hand a prematurely formed network can impair the stretchability of the film and make welding impossible, and on the other hand the network formation during or after shaping is achieved that the network strengthens the weld seam, since the network formation is continuous across the weld seam.

There is an essential difference here from the production of soft gelatin capsules, which are formed and welded on the basis of gelatinized gelatin, ie gelatin which already has a network, so that the gel or the network on the Weld is discontinuous. Naturally, the weld seam of gelatin capsules is a weak point.

Solubility and decay in aqueous media

The introduction of a network makes it possible to set high plasticizer contents, which means that the brittleness of the capsules can be overcome at low atmospheric humidity and at the same time the mechanical properties in the area of high atmospheric humidity are still guaranteed. However, since known networks impair transparency and lead to ^" water insolubility", two basic requirements are not met.

This problem could be solved on the one hand by setting networks with low network densities, whereby the transparency is hardly impaired, the network can disintegrate in water when swollen and a sufficient contribution to the mechanical properties is guaranteed, especially in high humidity. However, the scope is limited and the potential of the network cannot be fully exploited. On the other hand, therefore, possibilities were sought to maintain water solubility and transparency even with higher network densities.

As already mentioned, the control of the dimensions of the crystallites constituting the network points plays a key role. An influence is possible through process measures, in particular through heat treatments and / or through material requirements. At medium RF and lower temperatures, smaller crystallites are obtained due to the limited diffusion of the macromolecules than at higher RF and higher temperatures.

Since SCA with DPn of, for example, 24 in crystallized form, with the SCA as a helix with around 6 - 8 monomer units per rotation and a length per rotation of around O.δnm, the length is around 3x0.8nm = 2.4nm The size of the crystallites formed by combining such SCA with A-side chains of amylopectin is around 2.4 nm, the A-side chains being comparable to the SCA. This size is far below the 500nm required for transparency and such crystallites are also unstable in excess water at 37 ° C. With the choice of the molecular weight of the SCA, both the transparency and the water solubility or the decay in water can be influenced favorably. With increasing DPn of SCA, the tendency to form crystallite agglomerates increases, whereby transparency, water solubility and also the toughness are impaired. This trend also continues for DPn> 100, ie for LCA, which is why SCA is preferred in particular with lower degrees of polymerization DPn or higher molecular weight amylose with bsw. ^• by substituting corresponding reduced network-active chain length CLn, na.

The relationship between the length of linear polymers in the crystalline state and the size of the corresponding crystallites (lamella thickness) is known in the field of synthetic polymers, but it has not yet been recognized in the field of polysaccharides that this law can be used to advantage, especially for networks of high mechanical stability and elasticity, which can nevertheless disintegrate in water.

Larger crystallites can result from agglomerates or when using SCA or LCA with higher DPn. In the case of LCA in particular, branching degrees Qb which are too low can be disadvantageous, lead to opacity and water-insolubility, or prevent decomposition after swelling. However, transparency and water solubility can also be obtained with higher molecular weight SCA and LCA if, for example, these amyloses are substituted, the network-active chain length CLn, na is reduced and / or suitable process measures are taken, in particular the regulation of the water content down to low values and / or heat treatment with comparatively low RF after the production. Ie the same factors that enable the generation of advantageous networks, in particular networks coupled to the amorphous phase, also have a positive effect on water solubility and transparency. Complete solubility in water is not a necessary condition for the release of an active ingredient; disintegration of the material can also enable the release. In the context of this invention, since certain types of the viscoplastic material do not completely dissolve, but rather disintegrate, water solubility also means disintegration. Solubility in water is primarily determined by the above-mentioned measures relating to recipe and process; secondly, a positive influence on water solubility is also possible by using the following substances:

Retrogradation-inhibiting substances (RHS)

RHS can be used to advantage for tough elastic materials based on VS alone or a combination of VS and NS. Basically, there are substances of good water solubility that can be mixed with a network-compatible starch fluid (NSF). The retr ^{'ogradationshemmende} action of these substances is partly due to the reduction of the property of the strength as a plasticizer the water available, as well as in the dilution of the starch phase, whereby the diffusion of the starch macromolecules is difficult in both cases, and with respect to a crystallization existing incompatibility of RHS and strength. Examples of suitable RHS are types of sugar such as glucose, galactose, fructose, sucrose, maltose, trehalose, lactose, lactulose, refiniosis, glucose syrup, high maltose com syrup, high fructose com syrup, hydrogenated starch hydrolysates et. furthermore polydextrose, glycogen, oligosaccharides, mixtures of oligosaccharides, in particular with DE> 20, preferably> 25, more preferably> 30, most preferably> 70, maltodextrins, dextrins, pyrodextrins, in particular with degrees of branching Qb> 0.05, preferably> 0.10, even more preferably > 0.15, most preferably> 0.3.

RHS also improve the water solubility per se, in some cases have a favorable influence on the sorption behavior and in particular the types of sugar reduce the oxygen permeability considerably, which is why they are particularly advantageous for this reason. If retrogradation-inhibiting substances are unable to completely suppress retrogradation, dextrins, pyrodextrins, maltodextrins, oligosaccharides and glycogen in particular enable the dimensions of the crystallites produced by retrogradation to be controlled down to dimensions, whereby the transparency is not impaired and water solubility or decomposition in water is achieved can be.

Explosives (SM)

In accordance with the state of the art, disintegrants or disintegrants used in galenics are suitable as disintegrants, in particular fillers which are immersed in water. absorb a gas and / or swell strongly, which mechanically destabilizes and disintegrates. Examples are carbonates and hydrogen carbonates of the alkali and alkaline earth ions, in particular calcium carbonate, and soy proteins (for example Emco-soy) or preferably strongly swelling starch particles such as sodium glycolates (sodium salt of carboxymethyl ether starch), for example Explotab, Vivastar or Primojel. Salts can also be used.

Solvent (LM)

Solvents are understood in particular as non-starch polysaccharides or hydrocolloids which have good water solubility or strong swellability in water and are miscible with NSF or are present as a separate phase therein.

Optical properties

Measures that make networks soluble in water or gastric juice at 37 ° C also enable the setting of transparency, which is problematic in conventional networks (opacity). The corresponding measures have already been mentioned. This means that transparency of high quality can be obtained up to around 85% and higher, comparable to gelatin. While gelatin has a yellowish to brownish intrinsic color, films made from the tough elastic material are practically completely colorless. If pyrodextrins with a yellowish to brownish color are used to a significant extent, the color shade of gelatin is obtained.

The usual natural or synthetic dyes, such as those used for coloring, can be used. can be used to color gelatin capsules.

In terms of printability, starch has advantages over gelatin. This is understandable because starch is used in large quantities in the paper industry, which means that the printability of paper can be improved.

Surface properties

The stickiness is reduced compared to gelatin before the onset of network formation, since gelatin has a much higher water content at this point in time. With the The formation of the network reduces the stickiness continuously, after the completion of the network there is practically no stickiness.

impact strength

The same sample can appear tough at low speeds and extremely brittle at high speeds. This is particularly the case with substances based on starch and in the area of the transition from brittle to tough behavior. Since high stress speeds also occur in practice, the impact strength is crucial. In addition to the impact strength, which is expressed as the energy absorbed during the break (impact work) in relation to the cross section of the sample, the elongation of the sample up to the break ε «is also relevant as a measure of the deformability or toughness in the case of sudden stress. From the viscous elastic material based on starch according to the invention, astonishingly high impact strengths K of up to 1000 mJ / mm ² and more were obtained at around 33% RH, with strains ει <of around 25%, while under the same conditions TPS impact strengths of typically around 10 mJ / mm ^{2 were obtained} ε «~ 0% and soft capsule gelatins have impact strengths of around 400 mJ / mm ² and ε _κ ~ 25%. As already mentioned, the low toughness or the pronounced brittleness of TPS soft capsules is the central problem, which means that the corresponding technology can only be used to a very limited extent.

The toughness of TPS as well as of the tough elastic material according to the invention is primarily determined by the glass transition temperature Tg for a certain RF. The glass transition temperature is one way of characterizing a continuous phase transition in amorphous matter, characterized by an increase in the degrees of freedom of the components, resulting, for example, in increased heat capacity, thermal expansion, flexibility or increased toughness, the respective transition temperatures being able to have marked differences and a corresponding one at constant temperature Transition of the property depending on the plasticizer content can be observed. For the selection of the optimal plasticizer or the optimal plasticizer combination, the transition with regard to toughness as a function of the RF at RT, RFz, is decisive. For tough starch mixtures, RFz is <30%, preferably <20%, ie with these relatively low RF the material already has around half the maximum toughness. If glycerin is used as the plasticizer, the range is 20 - 40% glycerin, depending on VS, NS and other formulation parameters such as For example, retrogradation-inhibiting substances, RF _Z in the range of 15-30%, which ensures sufficient toughness in the problematic area of the lower RF.

The toughness of the tough elastic material can also be further improved, in particular at RF <33%, by adding a proportion of polyvinyl alcohol (PVA), in particular a proportion in% by weight in the range from 1-50, preferably 1.5-30, more preferably 2-20, in particular 3-15, most preferably 3-10. In principle, any PVA types are possible, preference is given to PVA types with degrees of hydrolysis <90%, more preferably <80%, PVA preferably being added to the NSF in dissolved form becomes.

Heat treatment and aging resistance

A process is referred to as heat treatment, in which the material is stored in an atmosphere and the atmosphere has a course of air humidity and temperature as a function of time. The heat treatment can be used to control the network formation and, if necessary, the retrogradation in the capsule produced. The network formation is suppressed at RT and in the range of about 0-30% RF, while it takes place with increasing speed in the range of about 60-90% RF. If the RF is too high, turbidity can occur, which is why heat treatments are advantageously carried out in the middle range of air humidity. By setting temperatures above RT, the heat treatment can be shortened, the suitable RF decreasing with increasing temperature. The duration of the heat treatment depends on the exact formulation and in particular on the degree of polymerization of the amylose and is in the range from hours to days. Here too, SCA offers advantages over LCA, i.e. short heat treatment times. Due to the greater mobility of the shorter molecules, heat treatment can also be omitted.

In addition, heat treatment is carried out in order to specifically anticipate rearrangement processes that would otherwise take place in an uncontrolled manner. This enables constant product properties and long-term stability to be maintained. additives

Additives and / or fillers and / or resistant starches can be added to the tough-elastic material as additives. In this regard, reference is made to the patent applications WO 03/035026 A2 and WO 03/035044 A2, as well as to the DE patent application dated 28.03.2003 which gives priority to the present application with reference 103 14 418.8.

method

With regard to various processes for the production of networks based on starch, reference is made to the patent applications WO 03/035026 A2 and WO 03/035044 A2, and with regard to the production by means of a preliminary product to the DE patent application dated 28.03.2003 which gives priority to the present application and has the file number 103 14 418.8 directed.

The process costs in the area of soft capsules are comparable to the process costs of gelatin capsules, except for the drying process. Since capsules are made based on the viscoplastic material with significantly lower water content compared to gelatin, the drying process can be reduced. With optimized process parameters, it can even be omitted entirely.

raw materials

The structure chosen to solve the task basically allows "various implementation options, whereby the parameters of the solution can be adapted and optimized in each case. For the implementation on the basis of starch there is greater scope with the wide range of commercially available starches (great starch manufacturers offer typically> 100 different starches, a total of> 1000 individual starch types and qualities, often with gradually graded properties, are available on the market. Therefore, a considerable number of individual solutions are possible using specific recipes and adapted process variants are listed in the description, in particular solutions based on cheap mass starches (commodity starches) of food quality can also be implemented and, in addition to the raw material price, Re requirements regarding availability, purity or GMO freedom are taken into account, boundary conditions that can also change over time. Overall, the price advantage for solutions based on raw materials of food quality compared to gelatin is remarkable with a factor of 2 - 7.

Advantages of the invention

The solution to the problem consists primarily in the selection of a suitable structure and the use of various polymer structures and mechanisms such as crystallization, nucleation, network formation or heat treatment, as a result of which an advantageous range of properties can be obtained. The invention discloses a new viscoplastic material based on starch which, in comparison with gelatin, has a flatter sorption isotherm and a flatter desorption isotherm, the equilibrium water contents generally being lower. This reduces the inevitable influence of RF, which reduces the range of material properties of the viscoplastic material compared to other substances that are suitable for capsules and edible films, and extends the range of applications.

The tough elastic material has an amazing toughness at low RF, which, for example. compared to TPS, where toughness is critical, ie the limiting factor, is improved by a factor of> 100 and at the same time good dimensional stability, ie a high modulus of elasticity, can be obtained at high RF. With regard to the balance between toughness and dimensional stability, a better property profile could even be achieved compared to gelatin. In addition, lower oxygen permeabilities can be set, which means that the range of possible applications can be increased compared to common gelatine and TPS (eg oxidation-sensitive active ingredients). As a result of the improved sorption behavior, water absorption is also reduced, which also increases the application options. The improved sorption behavior and the reduced oxygen permeability improve, for example. the shelf life of capsule formulations (galenics, aroma, perfume). Furthermore, the starches used are widely available and of high purity, compared to gelatin by a factor of 2 to 7 cheaper, and finally the process costs compared to gelatin capsules can be reduced as a result of a simplified or completely unnecessary conditioning process and by means of new processes (production of the films for the encapsulation regardless of the encapsulation process, provision of the films in the form of rolls). The The proposed solution thus fulfills the essential conditions for successfully replacing gelatin in the capsule area as a standard solution and setting new standards in the area of edible films.

Due to suitable measures regarding the preparation of the substances used, such as the selection of substituted starches as VS and SCA as NS, as well as activation of the NS and with the optimized parameters of the process, both soft and hard capsules can be obtained that meet the requirement profile and at least partially even have improved properties compared to gelatin.

The description of the invention make it clear that fundamentally different formulations enable usable solutions, the respective process parameters possibly having to be adapted. Since there is more scope for individual solutions, aspects such as raw material prices, availability, purity or GMO-free, i.e. boundary conditions that can change over time, can also be taken into account.

Examples

method

Batch process

Example 1: The batch process was carried out using a heatable Brabender kneader with a chamber volume of 50 cm ³ . In a first step, the VS was plasticized by adding water and plasticizer at mass temperatures of 80 - 90 ° C and 120 rpm for 3 minutes. At the same time, a solution from NS was prepared and mixed into the melt. The homogenization was carried out at 100 rpm for 10 minutes, the mass temperature rising continuously to 90-105 ° C. The finished mixture was then removed and formed into 0.5mm films in a press, which typically contained about 20% water. The films were then stored at different RF until equilibrium and analyzed for their properties. Various formulations for tough elastic materials as well as for reference materials are listed in Table 1. Preparation of the NS solution:

TL1: solution temperature, dT / dt: cooling rate of the solution, TL2: temperature of the solution when added to the VS melt, C: concentration of the solution

Continuous process, direct extrusion

Example 2: Extrusion parameters: 30mm twin-shaft extruder rotating in the same direction, closely intermeshing (20L / D), screw configuration: feed zone, distributive mixture (G3), dispersive mixture (G4), discharge zone (G5), speed 300 rpm, VS = 7.1 kg / h (dosage G1), NS solution = 3.3 kg / h (25% NS, 75% water, dT / dt = 50 ° C / min, dosage G2), plasticizer = 3.5 kg / h (dosage G3), Temperature housing G1 = 40 ° C, G2 = 80 ° C, G3 = 90 ° C, G4 = 90 ° C, G5 = 90 ° C. The final water content after extrusion could be varied in the range 10 - 30% using a vacuum.

The mixture was formed into a film of 0.6 mm thickness using a wide-angle nozzle and calibrated using a flat film take-off device (chili roll). The film can then be wound up and stored, processed further at a later time or it can also be bsw directly. processed into soft capsules via a rotary die system or into sachets via a welding and cutting system. If the film is stored temporarily, the water content should be around 25 - 35% at room temperature and around 15% at room temperature so that the network does not form. A very interesting state exists in the range of water contents of about 7 - 15% (provided that there is no or only a little developed network). At these ratios, the NSF is on the one hand in a state above the glass transition temperature Tg, ie the material is relatively soft and shows a very high elongation of typically 300% and more. On the other hand, the NSF in the NSF surprisingly remains in the molecularly disperse distribution for at least months. stood so that the good formability and weldability is preserved for as long. After processing, the network formation can then be triggered by an increase in the temperature and / or the water content, the material solidifying as a result of the onset of network formation and losing its weldability at low temperatures. It is not yet understood why network formation cannot take place under the conditions mentioned, but is apparently inhibited (network formation is also possible under these conditions in the presence of germs), although the material is soft and is above Tg, but it is observed state technologically of great use, e.g. with regard to the storability and further processing of the material. It is astonishing that the NSF solidifies when the temperature and / or water content increases, as one would initially expect the opposite, as is the case with TPS, but it is understandable that the resulting network provides additional strength As a result, this at first glance paradoxical phenomenon clearly shows a multifaceted difference between TPS and NSF or the strength network that emerges from the NSF.

Example 3: As example 1, but with NS solution added in G3, plasticizer in G2.

Example 4: As example 1, but prepared NS solution mixed with plasticizer (dT / dt = 30 ° C / min) and metered into G2

Example 5: As example 1, but the NS solution and plasticizer are each metered into G2

Process based on preliminary product

Example 6: (two-step process). In the first step, a preliminary product is produced, in contrast to Example 1 the throughput of plasticizer is 5 kg / h and granules are produced by strand or top granulation.

These granules (5 kg / h) are plasticized in a processing extruder by adding the rest of the plasticizer content (0.7 kg / h) and water (1.5 kg / h) and formed into films or into an injection molded body such as hard capsules. The temperature of the processing extruder in the plasticizing zone is around 90 ° C. characteristics

In illustration 1, the course of the modulus of elasticity as a function of the relative air humidity for recipes based on retrogation-stabilized starches (medium to high DS), which are particularly well suited for the tough elastic material according to the invention as a matrix or amorphous phase, and an extraordinarily good one Have film-forming ability. The formulations TPS soft 10, 11 and 12 show the basic problem of obtaining a material that can be used in a wide range of air humidity based on starch. These materials are relatively impact resistant at low RH of 20 - 30%, but with increasing humidity, water is quickly absorbed, which makes them very soft and sticky from around 40% RH, losing their firm character and gradually the properties of slowly flowing, highly viscous Accept liquids. The decrease of the E-moduli with the RF is dramatic, TPS soft 12 or so. varies in the RF range 20 - 40% by almost a factor of 1000. Such substances are extremely unsuitable for any application that is exposed to the atmosphere.

The formulations tough elastic 10-1, 10-2, 11 and 12 have a defined network, whereby on the one hand the impact-resistant behavior at low RF is not impaired, but on the other hand the mechanical properties such as. the modulus of elasticity can be stabilized at medium to high RF. Surprisingly, a quasi plateau of the modulus of elasticity in the RF range of around 40 - 75% was obtained, whereby the modulus of elasticity remains almost constant. The level of the quasi plateau depends on the one hand on the chosen VS and on the type and proportion of the NS. The comparison of tough elastic 10-1 with 10% NS with tough elastic 10-2 with 15 NS shows the influence of the NS portion. ^" '

Interestingly, the stress-strain curves of the tough-elastic material in the RF range of around 20 - 50% show a course that, for example, is comparable to the stress-strain curve of polyethylene, whereby a yield point, a subsequent plateau region and finally a hardening area can be determined. Figure 9 shows the stress-strain curve at RF = 33% as an example for tough elastic 10-1.

Figure 2 shows the elongations at break of the formulations of Figure 1. The elongations at break of the recipes Ten-elastic 10, 11 and 12 show a measure of around 45% RH. Maximum of a good 300% on and within a wide air humidity range of around 20 - 70%, elongations at break of at least 100% are obtained. This behavior reflects the excellent film-forming property in a wide water content range. The use of NS slightly reduces the maximum elongation at break compared to the formulations without NS, but here too it can be seen that the area of application for high RF can be significantly expanded by introducing a defined network.

Figure 3 shows the behavior of the E-moduli in function of the RF for two typical tough elastic materials according to the invention (tough elastic 1 and 2) as well as for a soft (TPS soft 1) and a brittle TPS (TPS brittle 1) and for soft capsule gelatin demonstrated. In the logarithmic representation, soft capsule gelatin shows a linear decrease in the modulus of elasticity with increasing RF and varies in the RF range of around 20-85% by a factor of around 600. Elastic 1 and 2 have a significantly reduced range of variation in this RF range a factor of 100 and in particular a quasi plateau in the middle RF range. This is a significant advantage over gelatin. While gelatin and tough elastic 1 and 2 at 22% RH have comparable moduli of elasticity, the elastic moduli of tough elastic 1 and 2 at 85% RH are around 10 to 20 times higher, which significantly improves the dimensional stability at high RH.

TPS soft 1 is based on a substituted starch with deep DS. This recipe shows what can be achieved in the most optimal case with respect to the modulus of elasticity at high RF if impact strength is to be maintained at the same time at low RF. The moduli of elasticity at higher RF are modest, however, at 58% RF only a value of 2MPa is obtained, while gelatin is still 8MPa, tough elastic 1 and 2 still 11 and 73MPa. As a result of the low DS, the starch used for TPS soft 1 is not very suitable as VS for inventive tough-elastic materials. In particular, this property is not sufficient for applications where decay in water is essential. In contrast to TPS soft 1, TPS brittle 1 shows E-moduli at higher air humidities, which are comparable to tough elastic 1. However, the impact strength at 32% RF with only 11 mJ / mm2 compared to 904mJ / mm2 with tough elastic 1 is extremely low, ie TPS brittle 1 is extremely brittle at low RF, the material breaks like glass with the slightest stress. The course of the tensile stress at 10% elongation as a function of the RF for the previously mentioned recipes is shown in Figure 4. The relationships regarding this property are analogous to the modulus of elasticity.

The course of the impact strength or impact work K as a function of the RF is shown for TPS brittle 1, TPS soft 1, and for tough elastic 1 and 21 in Figure 5. A starch-based material can be described as tough if the impact strength is at least 30mJ / mm2, but higher values are advantageous. TPS brittle 1 only becomes slightly tough above 40% RH, while tough elastic 1 becomes tough above 20% RH and tough elastic 21 even below 10% RH, i.e. even with extremely low air humidity, which normally hardly occurs, is tough. The transition from brittle to tough takes place at TPS soft 1 between 10 - 20% RH. The subsequent sharp decrease in impact strength at higher RF is due to the fact that the material becomes extremely soft with increasing RF and takes on the character of a highly viscous liquid.

In addition to the impact strength, the elongation at break in the impact test ε «is another measure for characterizing the fracture behavior. While TPS brittle 1 has no measurable elongation at break, elongation at break of 25% and more could be obtained with the tough elastic material, i.e. this material still behaves plastically even at high speeds.

Figures 3, 4 and 5 clearly show a basic problem of TPS. On the one hand, it is possible to set sufficient impact strength at low RF, but then at higher RF the material becomes very soft and flowing (minimal modulus of elasticity), or that a sufficient modulus of elasticity can be set based on TPS at high RF can, but then at low RF the material becomes extremely brittle. This behavior is due to the fact that TPS is practically completely amorphous, is glass-like below the glass transition temperature Tg and is present as a highly viscous liquid above Tg. Useful properties can therefore only be obtained in the transition area between the two states within a narrow RF range. In contrast to this, with the tough elastic material according to the invention, both toughness and strength properties (modulus of elasticity, strength, dimensional stability) can be achieved simultaneously in a wide RF range, with additional properties as required for specific applications being able to be set ( eg transparency, decay in aqueous media, water solubility). It is also of particular advantage that the properties can be almost stabilized in an RF range of typically 40 - 75% (quasi-plateau of the modulus of elasticity and strength).

Figure 6 shows the moduli of elasticity for various viscoplastic formulations as a function of the RF. On the one hand, it shows that the characteristic properties of the viscoplastic material according to the invention can be obtained by means of various formulations, on the other hand it is expressed that the level of the modulus of elasticity can be varied over a range comprising almost two decades.

The property profile of the tough-elastic material depends not only on the recipe, but also on the manufacturing process. A comparison of the properties as produced for the same recipe by means of a batch process (Brabender kneader, tough elastic 1) and by means of a continuous extrusion process (tough elastic 1 E) can be seen in FIG. 7. It becomes clear that the modulus of elasticity after the extrusion process lies in the area of the quasi plateau and above at a significantly higher level, whereby values 3 to 5 times higher were obtained in comparison with tough elastic 1, i.e. The advantages of the tough elastic material are even more pronounced in the production by extrusion than the results based on the batch process. Figure 8 shows that the elasticity of tough elastic 1 E compared to tough elastic 1 decreases slightly in the area of the maximum at medium RF, but increases at low and high RF. The better properties resulting from the extrusion process compared to the Brabender process are common and based on factors such as. higher homogeneity, fewer material defects, shorter process times.

In Figure 10, the sorption isotherms of tough elastic 1, 16 and 17 are compared with the sorption isotherms of gelatin. Gelatin absorbs more water in the entire RF range compared to the tough elastic material with the same RF. This is one of the reasons why various properties of gelatin show a higher dependence on the RF. The water absorption of the viscoplastic material can be reduced by specific recipe measures, in particular by the composition of the plasticizer (viscoplastic 16, 17), so that various other properties are less dependent on the RF. In particular for applications in the encapsulation area, but also generally in the area of packaging, good barrier properties to gases, in particular to oxygen, are advantageous (damage to the contents by oxidation). Figure 11 shows that the oxygen permeability of tough elastic 1 compared to soft capsule gelatin is reduced by a factor of 2 to 3, making another advantage over gelatin obvious. The oxygen permeability can be further reduced through recipe measures, especially through the use of sugar. Tough elastic 17 has oxygen permeabilities reduced by a factor Vz in the RF range 0 - 75% compared to tough elastic 1, while this factor is even% in tough elastic 16.

Based on a typical viscoplastic recipe, modified with the addition of 10% sugar, a film of 0.25mm thickness was produced using a Brabender kneader, from which bags containing liquid aroma concentrates and perfumes were produced using a pulse welding system. Even after one month of storage, the bags were still intact and an excellent barrier effect of the tough elastic material was found. After the bags were placed in cold water in water, a complete disintegration of the bags could be observed after 15 minutes, whereby the contents were released. This results in, for example. the possibility to manufacture sachets containing perfumes, which up to now consist of polyvinyl alcohol and are used in washing machines in order to maintain the washed clothes with an appealing fragrance. The advantage of such bags based on starch is on the one hand the price and on the other hand the very good biodegradability of starch. In the aroma area, the tough elastic material can encapsulate aroma concentrates, whereby the aroma is only released during use and up to this point the aromas can be very well protected over a long period of time and maintain their quality (top notes). Compared to previous encapsulation systems in the aroma area, the stability of the viscoplastic material at high atmospheric humidity and the absence of stickiness in the entire RF area is a major advantage. Furthermore, the release of medicinal substances from capsules consisting of the viscoplastic material was examined, the results meeting the requirements for pharmacopoeia.

Measurement methods and conditioning

Tensile test The tensile tests were determined at 22 ° C with an instron 4502 tensile testing machine at a crosshead speed of 50mm / min on standardized tensile specimens according to DIN 53504 S3, which were punched out from films of about 0.5mm thickness. The measurement results are to be understood as mean values of at least 5 individual measurements. The water contents of the tensile specimens conditioned at different atmospheric humidity were constant within the measuring accuracy during the duration of the tensile tests. The stress, σ was obtained as F / A, where F was the force and A the sample cross section at ε = 0. Elongation in% of the tensile test was obtained as ε = 100 (- l ₀ ) / l ₀ , where l _{0 was} the stretchable length of the sample between the clamps at the start of the tensile test and the length of the stretched sample. The modulus of elasticity was obtained as E = σ / ε.

impact strength

The impact toughness was determined according to the Izod Impact method with a Frank Impact Tester (type 53565, Karl Frank GmbH, Weinheim, Birkenau, Germany) with pendulum of 4 joules (high impact strength) or 1 joule (low impact strength). Film samples with a width of 5 mm and a thickness of about 0.5 mm were used as test specimens. The length of the samples between the two-sided clamps was 40mm. The elongation at break D «in the impact test was obtained as ε« = 100 (l _f - l ₀ ) / lo, where lo was the stretchable length of the sample between the clamps before the impact and H the length of the stretched sample after the break. The measurement results are to be understood as mean values of at least 5 individual measurements. During the tests, the water content of the samples remained constant within the measuring accuracy.

oxygen permeability

The oxygen permeability measurements were carried out with an OX-TRAN 2/21 (MO ^' CON Inc. 7500 Boone Avenue North, Minneapolis, USA) on films of 0.15 mm thickness, the oxygen permeabilities of starch film and gelatin film in a symmetrical arrangement at the same time were measured so that the relative values could be determined very precisely.

sorption The sorption measurements were carried out on samples previously dried to 0% water content (24 h at 75 ° C over phosphorus pentoxide) (square test specimens with an edge length of 5 mm and a thickness of 0.5 mm), which were then used for different RF adjusted by saturated saline solutions in 7 days Desiccators were stored. The desiccators were equipped with fans, which significantly reduced sorption times to equilibrium (7 days) compared to storage in a calm atmosphere. The water contents after sorption were determined by the loss of water during subsequent drying.

conditioning

The conditioning of the samples for mechanical analysis (tensile test, impact strength) was carried out in the same devices as were used for the sorption (7 days).

Symbols and abbreviations

RH [%] relative humidity: 0% <RF <100%

RT L ° C] room temperature (22 ° C)

Tg [° C] glass transition temperature

WM [%] plasticizer content (excluding water) based on starch and

Plasticizer, dsb w [%] water content, based on starch, plasticizer and water dsb [-] dry solid base, based on the dry weight

E [[MMPPa] Young's modulus σ _m [[MMPPa] maximum strength in tensile test (breaking strength) σιo% [[MMPPa] tensile stress in tensile test at ε = 10%

S [%] elongation at break in tensile test

FE (23- • 85) ["] range of variation of the elastic modulus in the RF range from 23 - 85%,

FE (4 ₃ -75 ₎ [-] range of variation of the modulus of elasticity in the RF range from 43 - 75%,

F _σ ιo% (23-85) [-] range of σιo% in the range RF from 23 - 85%,

F _σ 10% (23-85) ⁼ σi0%, 23 / θ ^" l0%, 85

F _σ ιo _% (43-75) [-] range of σ-ιo% in the RF range from 43 - 75%,

F _σ 10% (23-85) ⁼ σ-10%, 23 / θ ^" 0%, 85

K [mJ / mm ² ] impact work in impact test (izod impact test) ε «[%] elongation at break in impact test (izod impact test)

RF _Z [%] RF when changing from brittle to tough behavior at RT.

K (RFz) is defined as the arithmetic mean of the toughness of the plateau in the brittle region Ks and the maximum toughness K after the brittle-tough transition. Since Ks «KM is usually K (RFz) ~ V KM P ₀₂ [mlxcm / (cm ² x24hxatm)] permeability coefficient for oxygen ^•

AM [% by weight] amylose content, based on the starch, dsb PNS [% by weight] proportion of NS based on NS and VS, dsb PLCA [% by weight] proportion of LCA in% by weight dsb based on AP and LCA PSCA [% By weight] of SCA in% by weight of dsb based on AP and SCA P HS [% by weight] of RHS based on VS and NS and RHS PSM [% by weight] share of SM, based on VS and NS and SM p _L [% by weight] share of LM, based on VS and NS and LM

DP [-] degree of polymerization

DPn [-] number average of the degree of polymerization

DPw [-] weight average degree of polymerization

Qb [-] degree of branching of macromolecules (number of branched

Monomer units / number of monomer units) CL ■ [-] chain length (number of monomer units)

CLn [-] number average chain length; linear, i.e. unbranched

Chain segments CLn, na [-] number average of the network active chain length; Chain segments that can crystallize and participate in networks, i.e. unbranched and unsubstituted and non-sterically hindered chain segments CLw [-] weight average chain length

DS [-] Degree of substitution: 0 <DS <3.0

DE [-] dextrose equivalent: 0 <DE <100

BV [-] Blue Value

IA [g / 100g] iodine affinity

VS Present strength

NS Networkable strength

WM plasticizer, can be a single plasticizer or a mixture of different plasticizers

RHS retrogradation inhibiting fabrics (RHS)

SM explosives

LM solvent

AM amylose

AP amylopectin

A-AP A side chains of amylopectin

SCA short chain amylose (NS or part of NS) with DPn in the range of 10 - 100; SCA alone cannot form starch networks, only in combination with other starches with a higher degree of polymerization, networks consisting of such mixtures can still be formed at low plasticizer contents and low temperatures LCA Long Chain Amylose (NS or part of NS) with DPn> 100, can have LCA1 and / or LCA2

LCA1 LCA with DPn in the range of 100-300; LCA1 can form networks both alone and in combination with other starches, mixtures of LCA1 and VS can form networks at medium plasticizer contents and medium temperatures

LCA2. LCA with DPn> 300; LCA2 can form networks both alone and in combination with other strengths. Mixtures of LCA2 and VS can form networks at high plasticizer contents and high temperatures

NSF Networkable Starch Fluid; Melt or _solution containing a starch or a starch blend, and plasticizer; can be obtained as a strength network below under suitable conditions. An NSF has at least one VS and at least one NS

VP preliminary product obtained from NSF; If fluid is obtained from a network-compatible starch, it is an intermediate product in the DP process

VVP Cross-linked preliminary product obtained from NSF; has an at least partially developed starch network

IVP inhibited intermediate obtained from NSF; has no or only a minimally developed network, the formation of a network is suppressed by procedural measures. An IVP is predominantly to completely amorphous

KVP Pre-product containing germs obtained from NSF has a slightly developed network, the network elements of which act as germs in the processing of the KVP for the production of starch networks

SCP Split Continuous Process: VS and NS are prepared separately, mixed to form an NSF and the NSF is processed directly into the end product ^• .

TCP Together Continuous Process: VS and NS are processed together to form an NSF and the NSF is processed directly into the end product

SDP Split Discontinuous Process: VS and NS are prepared separately, mixed into an NSF and the NSF processed into a VP

TDP Together Continuous Process: VS and NS are processed together, mixed to form an NSF and processed directly into the end product

Claims

claims

1. Tough-elastic material based on starch, characterized in that this tough-elastic material makes a transition from brittle to tough behavior RF _Z as a function of the relative air humidity RF and at room temperature in% RH at <33, preferably <26, more preferably <20, most preferably <15 shows and at an RF of 85% it also has a modulus of elasticity E in MPa of> 0.1, preferably> 0.5, more preferably> 1.0, most preferably> 3, and each has <50.

2. Tough elastic material based on starch according to claim 1, characterized in that for its impact strength K in mJ / mm ² and modulus of elasticity E in MPa applies: a) at RF of around 11%, K> 10, preferably> 15, still more preferably> 30, most preferably> 50 and each <300; and b) at RF of around 85%, E> 0.1, preferably> 0.5, more preferably> 1.0, most preferably> 3, and in each case <50; and / or c) at RF of around 75%, E> 0.5, preferably> 1, more preferably> 5, most preferably> 10 and in each case <150.

3. Tough elastic material based on starch according to claim 1 or 2, characterized in that for its impact strength K in mJ / mm ² and modulus of elasticity E in MPa applies: a) at RF of around 23%, K> 15, preferably> 30 , more preferably> 50, most preferably> 100 and each <1000; and b) at RF of around 85%, E> 0.2, preferably> 1.0, more preferably> 2.0, most preferably> 5 and in each case <100; and / or c) at RF of around 75%, E> 1.0, preferably> 2.0, more preferably> 10, most preferably> 20 and in each case <300.

4. Tough elastic material based on starch, according to one of the preceding claims, characterized in that for its impact strength K in mJ / mm ² and modulus of elasticity E in MPa applies: a) at RF of around 33%, K> 20, preferably> 50, more preferably> 100, most preferably> 200 and each <2000; and b) at RF of around 85%, E> 0.2, preferably> 1.0, more preferably> 2.0, most preferably> 5.0 and in each case <100; and / or c) at RF of around 75%, E> 1.0, preferably> 2.0, more preferably> 10, most preferably> 20 and in each case <300.

5. Tough-elastic starch-based material according to one of the preceding claims, characterized in that the fracture is tough elastic in the impact test, ie that the material has an elongation ει <when broken, with ει _< in%: a) with RF of around 43 % is ει <> 5, preferably> 10, more preferably> 20, most preferably> 30 and in each case <50; and / or b) at RF of around 33%, ε> 3, preferably> 7, more preferably> 14, most preferably> 20 and in each case <35; and / or c) for RF of around 23%, ι _< > 2, preferably> 5, more preferably> 10, most preferably> 15 and in each case <25.

6. Tough elastic material based on starch, according to one of the preceding claims, characterized in that for its strength at 10% elongation σ _m , ιo _% in MPa applies: a) at RF of around 85%, σ _mι10% > 0.2, preferably> 0.4 , more preferably> 1, most preferably> 3 and each <12; and / or b) at RF of around 75%, σ _mi- ιo _% > 0.4, preferably> 0.8, more preferably> 1.5, most preferably> 5 and in each case <20.

7. Tough elastic material based on starch, according to) one of the preceding claims, characterized in that for its elongation at break ε in% applies: a) the maximum elongation at break ε _b as a function of RF is> 50, preferably> 100, more preferably> 200 , most preferably> 300 and each <600; and / or b) the elongation at break ε _b RF at RF of around 75% is> 20, preferably> 50, more preferably> 75, most preferably> 100 and in each case <200.

8. Tough elastic material based on starch, according to one of the preceding claims, characterized in that the material in the RF range of about 20-50% shows a yield strength in the tensile test.

9. viscoplastic material based on starch, according to any one of the preceding claims, characterized in that the viscoelastic material the modulus of elasticity and the tensile stress at 10% elongation as a function of RF has a quasi-plateau relative wherein aj the factor F _{E (23-85 )} the variation of the modulus of elasticity at RT in the range 23-85% RF <400, preferably <200, more preferably <100, most preferably <50 and in each case>1; or b) the factor F _{E ( 3-75) of} the variation of the modulus of elasticity at RT in the range 43-75% RF <50, preferably <20, more preferably <10, most preferably <5 and in each case>1; and c) the factor F _σ ιo _% (23-85) of the variation of the tensile stress at 10% elongation at RT in the range 23-85 _% RF <100, preferably <50, more preferably <25, most preferably <10 and in each case> Is 1; or d) the factor F _σ ιo _% (43-75) of the variation of the tensile stress at 10% elongation at RT in the range 43-75 _% RF <10, preferably <5, more preferably <3, most preferably <5 and in each case> 1 is.

10. Tough elastic material based on starch, according to one of the preceding claims, characterized in that at least one of the following properties apply: a) the ordered areas of the material which form the crosslinking points of the network have dimensions in nm <500, preferably <300, more preferably <150, in particular <100, most preferably <70 and are coupled to the mainly amorphous phase; b) the material is transparent at RF <50%, preferably <60%, more preferably <70%, most preferably <90%. c) The material is not sticky in the RF range at RF <70%, preferably <80%, more preferably <90%, most preferably <100%. d) the material swells in water or gastric juice and dissolves or disintegrates with a slight movement of these media, in particular at temperatures in ° C. <70, preferably <50, more preferably <40, most preferably <30 ° C.

11. Tough elastic material based on starch, according to one of the preceding claims, characterized in that the material is a starch with a network-active chain length CLn.na in the range 5-300, preferably 6-100, more preferably 7-50, in particular 8-30, most preferably 9-28, most preferably 10-27 and optionally the material has a further strength with a degree of branching Qb> 0.01, preferably> 0.05, more preferably> 0.10, most preferably> 0.15.

12. Tough elastic material based on starch, according to one of the preceding claims, characterized in that the material has a VS and an NS, the proportion PNS of NS based on NS and VS in wt.% Dsb in the range 1 <p _NS <90 , preferably 2 <PNS <50, more preferably 3 <PN _S <30, most preferably 3 <PNS <15. -

13. Tough elastic material based on starch, according to one of the preceding claims, characterized in that the material a) has an amylose content A _M in% by weight dsb in the range from 1 <AM <70, preferably 2 <AM <50, more preferably 3 < A <40, most preferably 3 <A <30 and b) the amylose is SCA, LCA or a mixture of SCA and LCA, the proportion PSCA of SCA in% by weight dsb based on amylopectin and SCA in the range 1- 35, preferably 2-25, especially 3-20, most preferably 4-14; and / or the proportion of PLCA of LCA in% by weight of dsb based on amylopectin and LCA is in the range from 1-70, preferably 2-50, in particular 3-40, more preferably 4-35, most preferably 5-30.

14. Tough elastic material based on starch, according to claim 13, characterized in that a) the SCA has a degree of polymerization DPn in the range 5 <DPn <70, preferably 6 <DPn <50, in particular 7 <DPn <30, more preferably 8 <DPn < 28, most preferably 9 <DPn <27; and b) the LCA has a degree of polymerization DPn in the range 100 <DPn <3,000, preferably 100 <DPn <1000, more preferably 100 <DPn <500, most preferably 100 <DPn <300; and c) if appropriate, the LCA has a degree of substitution DS in the range 0.01-0.50, preferably 0.02-0.30, more preferably 0.03-0.25, most preferably 0.04-0.20.

15. Tough elastic material based on starch, according to one of the preceding claims, characterized in that the material a) has a proportion of retrogradation-inhibiting substances (RHS), this proportion based on VS and NS and RHS in wt.% Dsb in the range of 1 <PRHS <70, pre- preferably 3 <p _RH s <50, more preferably 5 <PRHS <25, most preferably 7 <p _RH s <20; and / or b) has a proportion of disintegrant (SM), this proportion p _SM based on VS and NS and SM in% by weight dsb in the range 0.1 <p _SM <30, preferably 0..5 <p _S

15. more preferably 1 <p _SM <10, most preferably 1.5 <p _SM <7.0; and / or c) has a proportion of solvent (LM), this proportion p _L based on VS and NS and LM in% by weight dsb in the range from 1 <PLM <50, preferably 2 <PL <25, more preferably 3 <PLM <20, most preferably 4 <p _RH s <15.

16. Tough elastic material based on starch, according to one of the preceding claims, characterized in that the material has plasticizers and the following applies to the plasticizer content WM in% by weight dsb: a) WM is in the range of 10-60, preferably 15-50, more preferably from 20-40, most preferably from 25-35; and b) in particular the melting points of the plasticizers used in pure form at temperatures in ° C. <100, preferably <70, more preferably <50, most preferably <30 °; and c) in particular the plasticizer consists of> 50%, preferably> 70%, in particular> 80%, even more preferably> 90%, most preferably> 95%, in particular 100% of a plasticizer or a plasticizer mixture according to specification 16b).

17. Tough elastic material based on starch, according to one of the preceding claims, characterized in that for its permeability coefficient P ₀₂ of oxygen in [cm3mm / (m2) 24h] at RT applies: a) at 0% RH P ₀₂ <0.3, preferably <0.15, even more preferred ^« ? _, 0.07; and / or b) at 50%) RF is P ₀₂ <2, preferably <1, more preferably <0.5; and / or c) at 75% RH, P ₀₂ <20, preferably <10, more preferably <5.

18. Tough-elastic starch-based material according to one of the preceding claims, characterized in that the tough-elastic material or the molded end product consisting of this material is produced in the SCP or TCP or TDP or SDP process, the production using the TDP and SDP process a preliminary product takes place which has an at least partially formed network and is therefore present as an at least partially networked preliminary product (WP), or at most partially has a trained network and is therefore present as an inhibited preliminary product (IVP), or the preliminary product (KVP) is present as a germ which can be used for the formation of networks.

19. Soft capsule or soft capsule shell consisting of the tough elastic material based on starch, according to one of claims 1-18.

20. Soft capsule or soft capsule shell according to claim 19, characterized in that the soft capsule is used and used analogously to conventional gelatin soft capsules and is produced using a continuous encapsulation method, in particular using the rotary die method, the capsule preferably being analogous to the gelatin Encapsulation is formed from films fed symmetrically to the encapsulation system and these films are formed using standard methods such as, for example, extrusion or casting processes, the encapsulation being able to take place directly from the freshly produced films or the films having been produced beforehand, for example. temporarily stored as rolls and then used for the encapsulation; and a) if appropriate, the network formation is triggered shortly before, preferably during or shortly after the formation and welding of the soft capsule; and b) optionally the welding is carried out at temperatures in ° C. in the range 10-120, preferably 15-90, more preferably 20-70, most preferably 25-50; and c) if necessary, heat treatment or conditioning of the soft capsules is unnecessary.

21. hard capsule or hard capsule shell consisting of the tough elastic material based on starch, according to one of claims 1 to 18.

22 hard capsule or hard capsule shell according to claim 21, characterized in that dasä the hard capsule analogous conventional gelatin hard capsules used and used ^'and the hard capsule is produced by injection molding, wherein a) in particular the network formation short of, preferably at or shortly after the forming of the Hard capsule is triggered; and b) if necessary, heat treatment or conditioning of the hard capsules is unnecessary; or the hard capsule is produced in a dipping process analogous to gelatin hard capsules, the temperature in ° C. of the NSF in the dipping bath in particular being in the range 10-90, preferably 20-80, more preferably 30-75, most preferably 30-70.

23. Packaging based on the tough elastic starch-based material according to one of claims 1 to 18, in particular packaging and barrier for volatile substances such as fragrances and flavors, such as sachets for perfume or capsules containing water for flavors, fragrances, bath additives, chemicals and like.

24. Shaped part based on the tough elastic material based on starch, according to one of claims 1 to 18, wherein in particular the shaped part as a film, film, in particular as an edible film, as a filament, macro or micro fiber, in particular as produced in the gel spinning process oriented fibers, as foam, granules, powder, in the form of microparticles, in spray-dried form, in expanded form, as a molded part, in particular as an injection molded part, continuous casting, profile casting, deep-drawn part or as a thermoformed part.

25. Use of the tough elastic material based on starch, according to one of claims 1 to 18 in the food, galenics, cosmetics, health care, packaging or agricultural sector, etc. as cotton swabs, polystyrene foam replacement, film, bio-oriented film, composite film component, membrane system for nano, micro or macro encapsulation, paper laminate, replacement of cellulose, disposable clothing, dishes and cutlery, food tray, drinking straw , Cups, food packaging, foamed heat-insulating food container, chewing bones for the dog,, shopping carrier bag, rubbish and compost sack, mulch film, plant pot, golf tip, children's toys.