EP0522126A1 - Process and equipment for the production of a product containing starch and/or at least one starch derivative - Google Patents

Abstract

A material (5) consisting at least in part of starch and / or of starchy biomass, and / or at least of a starch derivative, which normally contains water (9) and / or alcohol , is homogenized and compacted in a feed and / or compression device (21) by means of a compression member (30) preferably consisting of a worm. The pasty material thus produced is pressed into the hollow space (39) of a gelling and / or mixing chamber (43), where it is mixed with a crosslinking substance (51) and, by adding steam, reheated , melted and gelled. In this way it is possible to manufacture a very homogeneous gelled mixture capable of being transformed into different products, for example a transparent film tape (95) or a foamy product.

Description

Method and device for producing a starch and / or product containing at least one starch derivative

Technical field of the invention

The invention relates to a method and a device for producing a starch and / or a product containing at least one starch derivative.

Starch-based products can be used, for example, to replace plastic products and generally have the advantage over them that they are better and / or less polluting and, in particular, are biodegradable and, moreover, are difficult to ignite.

State of the art

Several processes for producing various types of starch products are known per se. According to a process known from US Pat. No. 4,673,438 for producing pore-free starch products, a material consisting of starch and / or starch derivatives and water is heated and extruded in an extruder press together with an extender, crosslinking agent and lubricant. The resulting gelled mixture is processed into capsules and packaging containers by means of an injection molding device.

According to this known method, the starch is a temperature of 80 ° C to 240 ° C in the interior of the extruder press. However, the inevitable conveyance between successive turns of the helical rib of the screw impedes the simultaneous mixing of the starch with the added additives. Since, in addition, relatively high shear forces are exerted on the mixture present in the interior of the extruder press by the movement of the screw, there is a risk that the mixture will clump in the interior of the extruder press. This creates a homogeneous

Distribution of additives in the mixture additionally hampers and also makes it difficult to keep the pressure of the mixture constant when it is pressed out of the interior of the extruder press. This in turn has the disadvantage that it is practically not possible, especially when producing large objects, to produce them with a homogeneous density.

In the cited US-A-4 673 438 the production of packaging containers for packaging of

Food and other products mentioned. However, it seems doubtful whether relatively large and thin-walled containers can be produced by gelling a mixture containing starch and then injection molding this mixture, as are currently used as plastic containers for packaging foods. Furthermore, it should be at least difficult or even impossible to use the known method to produce containers that are sufficiently waterproof to pack moist or water-containing products, such as fresh meat.

In addition, the known method can hardly be used to produce larger, crystal-clear objects for which a homogeneous distribution of the crosslinking agent in the mixture is a prerequisite. Furthermore, foils cannot be produced by injection molding, as are desired as intermediate or end products for various purposes. According to a process known from EP-A-0 087 847 for producing foamed, gelled starch products, a material consisting of starch and / or starch derivatives and water is mixed in an extruder press together with a crosslinking agent and a blowing agent, at temperatures heated and extruded from 60 ° C to 220 ° C. Strands formed during extrusion can then be subdivided into foam cores with a grain size of 3 cm to 5 cm, which act as binders for foods or carriers of odor and

Flavor components as well as packaging material to protect fragile objects.

Since the mixture formed in the interior of the extruder press contains blowing agent and has the relatively high temperature already mentioned in the extruder press, puffing and foam formation with simultaneous solidification occur already in the interior of the extruder press and in the outlet which normally consists of a nozzle. the gelatinized mixture. Because the mixture is already foaming in the extruder press, it can only expand and expand a little more after flowing out through the outlet of the extruder press. If a sheet-like or strand-like article is produced by continuous extrusion as an intermediate or end product, its maximum cross-sectional dimensions are at most only slightly larger than the cross-sectional dimensions of the passage of the nozzle of the extruder press. The latter cross-sectional dimensions are in turn limited by the cross-sectional area of the interior of the extruder press. It is therefore hardly possible, for example, to produce large plates, such as those required for packaging television sets and the like. Furthermore, the foaming of the mixture in the interior of the extruder press prevents or complicates the pressure of the mixture when it is pressed through by a profile serving for shaping. To keep the tool or when pressing into a mold constant. This, in turn, has the disadvantage that it is practically not possible to produce objects that have the intended shapes and dimensions to a certain extent.

In addition, this method enables the production of foamed products only, but not the production of non-porous products, such as transparent films. Since, as already mentioned, a homogeneous distribution of the crosslinking agent in the mixture is the prerequisite for transparent products, the process known from EP-A-0 087 847, even if no blowing agent was added, would be trans for the production Parent products are not suitable, since a crosslinking agent added to the mixture before it enters the extruder press is also not homogeneously distributed in the mixture.

The method known from EP-A-0 087 847 also has the disadvantage that the starch and the water are only mixed with one another when they are introduced into the extruder press. In such a mixing process, the starch granules cannot swell or only swell slightly, which in turn prevents the crosslinking agent from being incorporated into the molecular structure of the starch and thus preventing the crosslinking agent from being homogeneously distributed.

Presentation of the invention

The object on which the invention is based is therefore to create a method and a device for the optional production of pore-free, for example transparent and also crystal-clear or foamed and porous starch products, the Disadvantages of the known methods and devices are to be remedied. In particular, the aim is to completely dissolve the starch during the manufacturing process both in the manufacture of a non-porous and in the manufacture of a porous product and to form a product which has the most homogeneous density, structure and crosslinking possible. Accordingly, when producing a non-foamed product, the aim is to ensure that it is actually completely non-porous and, if necessary, can be transparent and, for example, even transparent and crystal-clear. When producing a foamed product, it should also be possible for the material to be able to foam and expand if necessary after flowing out of a cavity in which it was gelled. Furthermore, it should be possible for the pressure of the die to be as constant as possible when passing through an outlet or when it is pressed into a casting mold and to have the intended size as precisely as possible, so that the or each resulting object is as precise as possible the intended shape, the intended dimensions and / or has a homogeneous density.

This object is achieved by a method having the features of claim 1 and by a device having the features of claim 33.

Particularly advantageous refinements of the method and the device emerge from the dependent claims.

In an advantageous embodiment of the method according to the invention, a material which contains starchy biomass and / or pure starch and / or at least one starch derivative and normally water and / or alcohol can be fed into a conveying and / or pressing device introduced and pressurized, mixed, compressed, moved in it with a movable conveying and / or pressing member and pressed through an outlet of the conveying and / or pressing device from the interior thereof into the cavity of a gelling and / or mixing chamber , possibly mixed with additives and heated, melted and gelled by adding steam.

The material or the starch-containing biomass and / or starch and / or the starch derivative is normally in a particulate state when introduced into the interior of the conveying and / or pressing device and namely consists, for example, of already swollen particles or grains. Furthermore, when the material is introduced into the interior of the conveying and / or pressing device, it preferably contains neither a crosslinking agent nor a blowing agent.

The conveying and / or pressing process taking place in the conveying and / or pressing device causes the material to heat up. If necessary, this can be additionally heated or possibly cooled in the interior of the conveying and / or pressing device by means of a heating and / or cooling device and brought to a favorable, relatively low temperature. As will be discussed below, the starch and / or the starch derivative of the material used - depending on the type of product to be produced - can contain at most little or relatively much amylose. At least if the material contains little or no amylose, the temperature of the material in the entire interior of the conveying and / or pressing device is expediently less than 60 ° C., preferably at least 30 ° C. and for example 40 ° C. to 55 ° C. For example, in experiments performed, a temperature of approximately 50 ° C was found to be very cheap. If, on the other hand, an amylose-rich material is used, it should preferably have the temperatures indicated above, at least in the first half of the interior of the conveying and / or pressing device.

If the temperature in the interior of the conveying and / or pressing device is set to a favorable, relatively low value in the manner described above and the material introduced into the interior is advantageously both free of crosslinking agents and free of blowing agents, this can be achieved when it is introduced The starch and / or starch derivative particles normally present in the interior of the conveying and / or pressing device lose their connection and disintegrate during the conveying and / or pressing process taking place, without any appreciable gelation taking place, without the starch and / or the at least one starch derivative clumps and without the material foaming. When the material is compressed and compressed, its viscosity also decreases again.

In a preferred embodiment of the method, an extruder or screw press with a cylindrical chamber which delimits an elongated inner space and has an inlet at one end and an outlet at the other end is used as the conveying and / or pressing device. A rotatable, axially non-displaceable screw can be arranged in the chamber as a conveying and / or pressing member, it being possible for there to be several of these. With such an extruder or screw press, the material is continuously conveyed from the inlet to the outlet and pressed out through it.

The material can from the interior of the conveyor and / or pressing device by a, preferably nozzle-shaped outlet, which forms a constriction, is introduced via a check valve into the cavity delimited by a chamber, namely pressed into it. The chamber is, for example, cylindrical and has a gelling and / or mixing chamber of a gelling and / or

Mixing device formed, which has a stirrer with at least one stirrer, which can be rotatable about the vertical or horizontal axis of the chamber, for example. In addition to the feed line connected to the outlet of the conveying and / or pressing device, at least one feed line can also open into the cavity, which feed line forms an inlet for introducing a crosslinking and / or blowing agent and / or possibly other additives. Furthermore, a plurality of openings for introducing water vapor and / or alcohol vapor preferably open into the cavity. The

The temperature in the cavity mentioned is preferably greater than the temperature in the interior of the conveying and / or pressing device and, depending on the type of material and the product to be produced, is preferably at least 80 ° C., normally at least 100 ° C., expediently at least 140 ° C, for example even at least 150 ° C or at least 160 ° C and for example at most about 240 ° C. The cavity is preferably sealed gas-tight to the environment, so that the material in the cavity can be kept under a pressure that is greater than the ambient air pressure. The pressure in the cavity is preferably at least 50 kPa and preferably at most 1.5 MPa greater than the ambient air pressure and can accordingly - measured absolutely - preferably at least 0.15 MPa and, for example

0.3 MPa to 2.5 MPa. The material present in the cavity is preferably heated at least in part and, for example, completely by the water and / or alcohol vapor supplied, which is preferably overheated. The steam preferably has a temperature of more than 100 ° C., suitably at least 120 ° C., preferably at least 140 ° C, preferably at most 240 ° C and for example 150 ° C to 200 ° C temperature. The steam is preferably introduced into the cavity in such a way that at least a part - for example the largest part - is dissolved by it as steam or gas in the material. At least a part of the steam introduced into the material, namely preferably most of it, and possibly all of the steam introduced into the material should then be removed from the material again. This can be done, for example, by passing the material out of the cavity and through a steam separator. However, it is also possible to completely or partially extract the water and / or alcohol vapor from the material if it flows out through an outlet, the pressure of the material drops to the ambient air pressure and the material also comes into contact with the ambient air. The steam supplied in the cavity mentioned can partially or completely condense when flowing through a line connecting the cavity to the said outlet, so that the substance forming the vapor is partially or completely in the liquid state when the material flows out of the outlet and separates as a liquid from the gelled material. Under certain circumstances, it is even possible to partially or even completely extract the steam introduced into the cavity from the material itself and to guide this vapor out of the cavity, for example, via a steam outlet provided with a pressure relief valve.

The material can be processed in the preferably existing extruder or screw press or at least in the first half of the path through which the material travels in a relatively dry state. The material can be quasi homogeneous, pasty

State. The one in this state A crosslinking agent and / or a blowing agent and possibly at least one other additive can be added to the gelling and / or mixing chamber in the cavity of the gelling and / or mixing chamber. The water and / or alcohol vapor can supply thermal energy to the material in the cavity and distribute it evenly in the material. Furthermore, for example, at least part of the water and / or alcohol vapor in the cavity can be converted into a liquid and absorbed by the material. The liquid brought into the material in this way is evenly distributed in the material. By adding steam and using the at least one stirrer, the flowable material is mixed homogeneously with the aforementioned additives. The flowable material present in the cavity is therefore heated, melted and gelled evenly by the water and / or alcohol vapor and the stirring. The supply of water and / or alcohol vapor in particular prevents the flowable material from partially clumping in the cavity of the gelling and / or mixing chamber and from being deposited on the inner walls of the cavity.

The flowable, gelled, and preferably additive-containing material formed in the cavity is also referred to below as a mixture and can be in a more or less warm state under the influence of that produced by a conveying and / or pressing device and / or by the steam Pressure through a closed cross-section line, which can be heated or cooled if necessary, and an existing steam separator, for example, are pressed out of an outlet. The outlet can be formed, for example, by a slot die, a casting head or a profile tool. The profile tool has at least one passage through which it passes continuously to extrude the pressed mixture.

The mixture formed in the cavity mentioned is preferably continuously discharged from this cavity and, for example, continuously formed into an intermediate or end product when and / or after it flows out of an outlet, for example rolled with a rolling mill to form a sheet forming a film. The gelled mixture can also be fed to a conveyor belt through an outlet, for example in the form of a slot die. However, it is also possible to continuously introduce the gelled mixture through an outlet into an open-topped duct. Its bottom can be formed, for example, by a conveyor belt or have conveyor rollers, so that the strand or the web which is formed when the mixture continuously flows out is transported away from the outlet.

The gelled mixture can have approximately the same temperature during the shaping as during gelling in the cavity mentioned, the temperature during the shaping being, for example, up to about 220 ° C. However, in many and important cases, the starch-based material can also be plastically deformed at lower temperatures, at most about 120 ° C., expediently about 20 ° C. to 80 ° C. and preferably 40 ° C. to 70 ° C., and for example to give films or other materials ¬ term strands are rolled and / or drawn and / or cast into molded parts. The gelled mixture flowing out, for example, via a steam separator is therefore allowed to cool down for a certain period of time after the gelling and can then be shaped into the desired objects. If necessary, the mixture formed in the cavity mentioned can flow out between this and the shaping process with a heating and / or cooling device for one Shaping optimal temperature can be brought.

For the process according to the invention, all types of biomass containing starch and / or unmodified starches and / or starch derivatives can be used individually or mixed as a raw material. Starch is produced in large quantities by plants. In addition, in certain industrial processes in which plant products are processed, by-products or waste products are obtained which consist entirely or partly of starch and / or starch derivatives. A starchy plant is, for example, reed, in particular the Chinese reed that grows freely in China and other Asian countries and contains about 40% to 50% by weight of starch. Italian reeds also contain quite a bit of starch. Furthermore, potatoes or - more precisely, potato tubers - rice grains, wheat grains, corn kernels and peas contain a lot of starch. Furthermore, the straw obtained during the harvest of various cereals also contains some starch. The plants and parts of plants mentioned usually contain water and other substances, in particular cellulose, in addition to the starch. The material consisting of starchy biomass and / or starch and / or at least one starch derivative can be procured and made available in a simple, inexpensive and environmentally friendly manner.

If a product to be produced is supposed to be light, glass-clear and colorless, a material is preferably used which preferably contains starch and / or at least one starch derivative which, apart from the water normally contained in vegetable raw materials, is as pure as possible is. The material should then, in particular, also be as free as possible from cellulose and other vegetable constituents which can cause clouding or coloring. If, on the other hand, a non-porous or porous To produce a product that only needs to have a small translucency or that can or should be opaque and / or colored, a particulate material can be used that, in addition to at least one starch and / or at least one starch derivative, also cellulose and / or contains other herbal ingredients. The material can then contain, for example, a biomass that has reeds and / or straw that has been processed into small particles by cutting and / or by grinding and / or grinding. Since straw, in particular, contains only relatively little starch, this biomass can be mixed with another starch-rich material, for example more or less pure potato starch.

Any starch derivative present in the material can be formed, for example, by esterification and / or etherification and / or oxidation and / or by partial hydrolytic degradation of starch.

A material with starch and / or at least one starch derivative which contains little or no amylose can be used for many purposes. Such a material, such as potato starch, is available at particularly low cost and is also relatively easy to gel.

However, if waterproof products are to be produced and in particular if they are very thin in cross-section in at least one direction and have, for example, a thin film, a thin-walled container or a thin thread, it is advantageous that at least one component of the said Contains a relatively large amount of amylose. The material can, for example, have a starch-rich starch - for example corn starch - and / or a starch derivative - for example slightly esterified corn starch - which, based on its own weight, has at least 30% by weight or even contains at least 35% by weight of amylose. The proportion of this amylose-rich starch or the amylose-rich starch derivative in the total material consisting of starch and / or at least one starch derivative is preferably at least 1% by weight, preferably at most 60% by weight, suitably at least 3% by weight and Expediently at most 20% by weight and for example at least 6% by weight to at most about 15% by weight. The remaining starch, which may be material, then need have no or at most little, for example at most 10% by weight of amylose. The proportion of amylose in the total material consisting of starch and / or at least one starch derivative can accordingly be at least 0.3% by weight, suitably at least about 1% by weight and for example at least about 2% by weight. If the material contains a lot of amylose, it should be heated in the cavity mentioned for gelling to a temperature which is preferably at least 140 ° C. and even better, for example at least 150 ° C. and for example up to about 180 ° C. or even up to about Is 200 ° C.

A material containing starchy biomass and / or more or less pure starch and / or at least one starch derivative is preferably introduced into a mixer in a particulate state, ie as a granulate and / or granular and / or powdery bulk material and in this preferably at ambient temperature - ie without heating - and therefore normally at a temperature of about 20 ° C. and less than 30 ° C. with water and / or alcohol serving as solvent and / or dispersing agent and possibly with extenders and / or others Mixed materials. The biomass, starch and / or starch derivative particles can be, for example, with at least one rotatable Stirrer formed mixing tool are moved. The particles swell due to the absorption of water and / or alcohol, which also increases the viscosity of the material.

It should be pointed out here that the starch produced by plants has a certain moisture, the water content of starch freshly obtained from plants, for example potatoes, typically being about 15 to 25% by weight. If the starch or a starch derivative is obtained from plants which have been stored for a long time and / or have already been pretreated in some way and / or as a by-product of any industrial processing, the water content can also be smaller or larger. The amount of water and / or alcohol added during mixing can be matched to the already existing water content of the starch or starch derivative in such a way that the total amount of water and / or alcohol present in the material is at least 2% by weight and at most 60 % By weight and preferably 10% by weight to 35% by weight. For clarification, it should be noted that these percentages relate to the total weight of the moist material that is introduced into the gelling cavity. The material can normally contain water as a solvent and / or dispersing agent. However, if very thin, flexible films or tapes and / or thin, film-like coats or thin-walled hoses, bags or containers or thin threads are to be formed, it can be advantageous to add alcohol instead of water to the material and possibly even that already in to replace the water present in the vegetable starch with alcohol, because the film or the object otherwise produced then dries faster.

If an amylose-rich material is gelled, it can this may even be introduced into the cavity used for gelling in a completely dry state, ie without water and without alcohol. In this case, in addition to water vapor and / or alcohol vapor, water and / or alcohol in the liquid state may also be added to the material in the cavity mentioned.

The crosslinking agent which is at least normally still added to the gelled starch material in the cavity can, for example, have melamine resin and / or melamine and / or urea and / or formaldehyde and / or urotropin and / or glyoxal and / or glucose. A melamine resin formed from melamine and formaldehyde, which serves as a crosslinking agent, can be dissolved in the material, for example as a particulate material - for example as granules - or dissolved in formaldehyde and thus added in the liquid state.

Due to the type and degree of networking and / or other modifications, the properties of the products subsequently created, ie objects, can be adapted to the intended use. For example, the resistance or - seen the other way round - the rate of rotting can be controlled by the type and amount of the crosslinking agent added. For example, if starch left in its natural state is placed on or in a humus soil, it rots relatively quickly under the influence of soil bacteria. However, resistance to rotting can be increased, for example, by admixing and metering in a crosslinking agent which reduces water solubility, such as melamine resin or melamine or urea or glyoxal, for example by appropriate metering of the melamine resin and / or or melamine content and / or urea content, depending on requirements, even with a thin flexible film, a shelf life and durability of at least 5 years or at least 10 years or, if necessary can be guaranteed for even more years. The total proportion of crosslinking agent, in particular when using amylose-free or at least low amylose starting materials, is in many cases for example at most 1% by weight or even only at most 0.1% by weight of the more or less dry material containing starch and / or at least one starch derivative . Incidentally, even in the case of a product made permanently by melamine resin and / or melamine and / or urea and / or glyoxal, rotting is still possible in a natural environment, only then it takes longer.

If the material contains amylose-rich starch or an aylose-rich starch derivative in the manner described above and is intended for the production of waterproof products, the material as crosslinking agent is preferably melamine resin and / or melamine and / or urea, and preferably additionally glucose attached. For the formation of pore-free, completely water-resistant products, the crosslinking agent content can then be at least 10% by weight and up to 30% by weight of the more or less dry or even water and / or alcohol-containing material introduced into the gelling cavity. The melamine resin - and / or melamine and / or urea fraction - based on the total starch and / or at least one starch derivative and water and / or alcohol-containing material introduced into the gelling cavity - preferably at least 10% by weight and preferably not more than 15% by weight. The proportion of glucose - based on the material mentioned - can preferably be at least 2% by weight and preferably at most 12% by weight.

Of course, other additives can also be added to the material later in the gelling cavity can be added to achieve certain properties of the products. For example, at least one additive for additionally reducing the water solubility and / or at least one hardener can be added. The addition of magnesium sulfate, for example, improves the moisture-resistant properties of starch products. Although starch-based products are inherently flame-retardant and poorly flammable, it is possible, for example, to additionally add at least one flame-retardant substance. At least one dye can also be added to color the otherwise normally colorless products.

The objects formed by shaping from a gel solidify after being shaped and are then relatively tough and, with a correspondingly thin cross-sectional dimensioning, are also flexible. In an advantageous embodiment of the method, the objects formed from the gel are dried by heating to accelerate the setting and solidification process, so that at least a part of the water and / or. Originally present as a solution and / or dispersion liquid is dried Alcohol escapes. If, as mentioned, compact, pore-free and / or transparent objects, for example foils, are to be produced, their drying can be carried out, for example, at least in part by irradiation with infrared light. If a film is produced, it can, for example, be irradiated simultaneously from both sides - that is, for example, from above and from below in the case of a film running along a horizontal plane. When drying by infrared light irradiation, the outermost layers are first heated and dried, so that the liquid withdrawal proceeds from the outside inwards. This promotes the formation of largely non-porous, clear and even transparent films or other objects. For the continuous production of a web serving to form a film or a band, the gelled mixture can be fed, for example, through an outlet, for example as a slot die, to a rolling device or a device with a conveyor and / or casting belt and at least one shaping tool , that is formed by a wedge and / or knife-like scraper. With the help of suitable profile tools, it is also possible to continuously produce strands and webs with any other profiles - for example, tubes or hoses - by rolling processes, extrusion and / or extrusion and other shaping methods. The widths and thicknesses of the foils or tapes or the other cross-sectional dimensions in any way of profiled strands can of course be determined as required by appropriate dimensioning of the profile tool used.

Furthermore, at least one flavor and / or smell substance can be added to a material used to produce a film, for example to keep moths and possibly other insects or other animals away. Such a film can then be used to form a sack or container for storing clothes.

Transparent films or tapes based on starch can furthermore be used as writing and / or image carriers for so-called bright room or "overhead" projectors. Solc foils or tapes are often used only once and for a short time and then thrown away, so that degradability with such foils or tapes that is environmentally friendly is also very advantageous.

If compact, pore-free and / or translucent, spatial molded parts are to be produced, the gelled starch mixture are first continuously formed into a sheet. This can then - for example before it is completely dry and solidified - be shaped in a shaping device into spatial shaped parts, such as containers. Such molded parts can be used, for example, as packaging material for foods such as vegetables, meat or chocolates.

If non-porous objects, such as

Films, tapes or molded parts are produced, polyethylene starch can be added to the starch and / or at least one starch derivative material when it is introduced into a conveying and / or pressing device or at the latest when gelling. The polyethylene oxide can be added to the rest of the material, for example in dissolved form. The proportion of polyethylene oxide in the total starch and / or mixture containing at least one starch derivative is preferably at most 30% by weight and, for example, 0.5 to 5% by weight. Maybe the

In addition to the polyethylene oxide, a small amount of at least one other water-soluble synthetic resin can be added to the mixture. Its proportion in the mixture can be, for example, 0.5 to 4.5% by weight. Objects molded from polyethylene oxide material have a relatively smooth surface. If the material, for example for shaping at least one object in a flowable or semi-solid state, is shaped with at least one tool and / or at least one device, for example rolled with rollers and possibly additionally formed with a forming device or cast into a casting mold, the added polyethylene oxide acts against sticking the material to the tool or device. Furthermore, the surface of such an object can be provided with at least one pattern that is linear and / or punctiform depressions. These depressions can be embossed with at least one, for example, heated embossing roller or with a heated embossing stamp into the material which has already been formed into an object by rolling or casting or the like, but is not yet completely solidified. Instead, the depressions can possibly be burned in with a laser or produced by a shrinking process or by machining. In one advantageous embodiment, the depths of the depressions and / or their spacings from one another are at most 0.01 mm, better than 0.001 mm and for example only 1 nm to 10 n

Furthermore, a layer of polyethylene oxide can be applied to an object which consists of a starchy material without polyethylene oxide. It is also possible to apply a starch mixture containing polyethylene oxide to a surface of an object, such as paper, wood or textile fabric. Finally, there is also the possibility of applying a thin metallic layer to at least one area of the surface of a starch and / or at least one starch derivative, for example by vapor deposition. In this way, objects with smooth surfaces can be formed, which can subsequently also be provided with fine, line-shaped or punctiform depressions.

Patterns with depressions of the type mentioned produce by diffraction and

Interference processes different light effects and different colors. Objects with such patterns, for example characters and / or at least one image, can be formed, for example, as packaging material, as a container for food or possibly as securities or tickets. The gelled mixture can also be continuously formed into threads which can be dried by hot air treatment and further processed, for example, into cords and ropes or into cotton-like starch products.

If foamed starch products are produced, they can have sizes and shapes which can be selected within wide limits. For example, larger foam bodies can be produced for packaging devices or fragile objects or structural masses for backdrop construction and for interior decorations. In the production of foam bodies, the gelled mixtures containing the starch and / or at least starch derivative can be irradiated with microwaves in a dryer after a more or less extensive preforming and partial foaming with an advantageous embodiment of the method. The preliminary product in the dryer is then progressively heated and dried in it by the microwaves from the inside out. The bubbles which form during the evaporation of water and / or alcohol cause the gel to foam and thereby further deform and become porous.

In the production of foam products, however, it is also possible, for example, to produce small foamed foam granules which can be used as packaging material by injecting the gelled mixture dropwise into a hot air stream.

To increase the pore formation, a blowing agent can be added to the material before the foaming process. This can, for example, consist of at least one salt, for example a metal carbonate, such as lime or calcium carbide, and / or an inorganic acid, for example hydrochloric or phosphoric acid, and / or an organic acid, for example citric acid, and / or hydrogen peroxide and / or aluminum oxide and / or cement. The amount of propellant added can contain at least about 0.01% by weight, at most about 20% by weight and, for example, about 0.1% by weight to 5% by weight of the water and / or alcohol, in the mixed state for gelation serving cavity brought material. The percentages can be based on the amount of starch material and / or at least one starch derivative, or on the amount of this material, water and / or alcohol, normally containing a crosslinking agent and possibly additional substances be introduced into the cavity of the gelling and / or mixing chamber. So that any added blowing agent does not already cause foaming and gumming of the material in the press used for homogenization, the blowing agent is advantageously added to the gelling material only in the cavity of the gelling and / or mixing chamber.

A foam strand formed by foaming can then be formed into desired objects in an even more or less flowable state by rolling, pressing or casting or the like, or in pieces in a more or less soft or solidified state using a separating device, such as plates or chips, be separated.

Manufactured by the method according to the invention

Starch foam products or articles can have a minimum of about 5 mg / cm 3, a maximum of about 600 mg / cm3 and

3, for example, have a density of 100 to 400 mg / cm.

The starch-foam articles produced can depend on the production process, the composition, and the like

Shape and the dimensions are dimensionally stable, hard and rigid, that is to say they cannot be elastically compressible. However, it is also possible to produce film-like or band-shaped foam articles which, although not, or at least are not highly elastically compressible, but are nevertheless bendable. Furthermore, foam products can be produced that are elastically compressible at least to a limited extent.

Furthermore, in particular in the case of porous starch-based objects, there is the possibility of adding sweeteners and / or flavorings and / or spices and / or nutrients of any kind to the production. Products of this type can then be used, for example, for packaging foodstuffs and / or as plates, drinking cups or the like, and can then be consumed. Porous starch foam articles with additives of the type mentioned can also be provided as actual foodstuffs and, for this purpose, can also be fried in oil, for example, so that crispy stems and cookies for nibbling are produced.

In the production of foam products, there is also the possibility, for example, of adding acetyl anhydride and / or sodium acetate and / or cellulose diacetate to the material, and possibly also adding a small amount of diatomaceous earth, acetic acid and / or glycerol. By adding these substances, the foam products become tougher and more stable and can be deformed before their final solidification without destroying the pores. Such a product can have, for example, 0.5% by weight to 5% by weight of cellulose diacetate, 0.5% by weight to 3.5% by weight of diatomaceous earth and a maximum of 0.075% by weight of glycerol. In this case, the glycerin has the property of a plasticizer and prevents the starchy material from clumping together.

Furthermore, there is the possibility, by means of electrically, hydraulically or pneumatically operated piston presses, of a gelled, flowable one containing a propellant Starch mixture by pressing, for example, a heated nozzle and injecting it directly into spaces between walls or the like, so that after foaming and drying they form foamed filling and / or insulating materials.

Liquid starch products can also be produced. Products of this type, for example as impregnating or coating materials, can be sprayed or sprayed onto the objects to be coated as required using a spray device operated with compressed air. The starch-based coating materials that can be produced by this method can be used in the processing of cardboard, paper and wood and as a more environmentally friendly replacement product for protective wax layers in road vehicles. Due to their pore-filling properties, these products are also suitable for mixing with water-soluble paints and / or other conventional impregnating agents.

It is also possible to add various extenders to the starch material, such as water-soluble gelatin, plastic waste, quartz sand, lime, cement, slate dust, ceramic dust, stone dust and / or cellulose-containing materials, such as sawdust, sawdust, paper or straw, the latter - such as already mentioned - can also contain a little starch. These extenders can be used together with the starch and / or with at least one material containing a starch derivative as well as water and / or alcohol by means of a conveyor and / or press device or an extruder or screw press, or directly into the cavity of the gelling agent. and / or mixing chamber and are added to the starch material at the latest in this cavity. Depending on the use, the material containing the extender can foamed and porous or non-porous and flexible as well as easily formable or rigid starch products are produced.

When using plastic waste as

Extending agents can be added to the starch material granulated plastic waste, preferably consisting of polyvinyl chloride and polyethylene. The proportion of plastic waste can be, for example, 5% by weight to 95% by weight of the mixture consisting of starch and / or at least one starch derivative and the plastic waste. In order to achieve an even better miscibility of the different plastic waste, glucose can be added to the plastic-starch mixture. The objects produced according to this process can be further processed and screwed together well by machining operations such as sawing and drilling. These very water and acid resistant items can e.g. can be used in the construction industry as switching and underwater components as well as guard rails.

By appropriately determining the composition of the material and the process parameters, both a blowing agent-free and a blowing agent-containing mixture can be produced and through an outlet into one

Channel is introduced, which is so flowable that it can be evenly distributed over the entire width of the channel if it is much wider than the mouth of the outlet. If the gelled mixture contains a blowing agent, it can still be in a largely non-foamed state when it flows into the channel and can only be foamed in the channel. The method according to the invention therefore enables the production of pore-free and foamed, porous webs which have a large width in comparison with the width of the outlet. However, the mixture can also be intermittent into one Casting mold or alternately into different casting molds and, for example, pressed into them. The or each casting mold can be closed on all sides or open at the top. In the same way as when introducing the mixture into a channel, it is possible to produce relatively large objects, for example foam sheets used for packaging large apparatus.

If the end products are to be formed by casting in molds or by inflation and thus to be shaped discontinuously, instead of an extruder or screw press, a screw-type piston press or a piston press can also be used to feed the starchy mixture into the gelling cavity, which acts as a pressing member has a rotatable and axially displaceable screw piston in its cylindrical chamber or an axially displaceable piston.

Brief description of the drawing

The invention will now be explained with reference to exemplary embodiments of devices for producing starch products shown in the drawing. In the drawing shows

FIG. 1 shows a schematic representation of a device for producing a non-porous, film-forming web,

FIG. 2 shows a schematic representation of part of a variant of a device for producing molded parts by means of a forming device,

FIG. 3 shows a schematic illustration of part of a variant of a device for producing molded parts by means of a centrifugal casting device, FIG. 4 shows a schematic representation of part of a variant of a device for producing pore-free threads by means of a centrifuge and

FIG. 5 shows a schematic representation of part of a variant of a device for producing foam articles.

Preferred embodiments of the invention

The device shown in FIG. 1 for producing a sheet forming a film from a flowable material has a feed system 1. This has a memory 3 which contains a material 5 which consists of starch containing some water. There is also a reservoir 7 which contains water 9. The memory 3 is connected to a mixer 15 via a metering device 11. The reservoir 7 is connected to the mixer 15 via a metering device 13. The metering device 11 has, for example, a worm and a drive device for driving it, while the metering device 13 is formed, for example, by a pump and a valve. The mixer 15 has a container and approximately at least one mechanical tool that can be moved in it with a drive device. The Auεgang deε mixer 15 is connected via a, for example, a screw and a driving device au ^f facing metering device 17 to the inlet 19 of a Fδrder- and / or pressing device 21st The conveying and / or pressing device 21 is designed as a press, namely as a screw press. This has an elongated chamber 23, the wall of which, as the main part, has a cylindrical jacket with a horizontal axis 25 and which delimits an interior space 27. At the end of the chamber 7 located on the left in FIG. 1, an inlet 19 opens into the cavity 27. At the end of the chamber on the right in FIG. 1 there is an outlet 29. Furthermore, the chamber 23 may also have two additional inlets, not shown in FIG. 1, namely a liquid inlet and a steam inlet. The two additional inlets, if any, open - in relation to the conveying direction of the conveying and / or pressing device 21 - in the rear half and namely even in the rear third of the interior 27 in these. The liquid inlet can be connected to the reservoir 7 via a line 28 and a metering device 14 formed by a pump and a valve. In the interior 27, a conveying and / or pressing member 30, namely a screw is axially immovably mounted, which with a motor and, for example, also a

Gear device drive device 31 can be rotated about the axis 25. The jacket is provided at least in a partial region of its length with a heating and / or cooling device 33, which has, for example, a pipe coil for passing a heating or cooling fluid through it. The jacket is enclosed by an outer jacket serving as thermal insulation 35. The outlet 29 of the conveying and / or pressing device 21 is connected to a check valve 37. This has a passage 37a delimited by a preferably heat-insulating wall 37b and a movable locking element 37c which is formed, for example, by a spring-loaded flap. A gelling and / or mixing device 38 has a gelling and / or mixing chamber 43 with, for example, an elongated, cylindrical, vertical jacket and two

End walls. The inside of the wall consists essentially of metal, for example it is provided with a thermal insulation (not shown) and delimits a cavity 39. The gelling and / or mixing device 38 also has a mechanism with at least one rotating in the cavity 39 about the vertical axis of the jacket Stirrer 41 and a drive device serving to rotate this, which is formed, for example, by an electric motor and a transmission. The gelling and / or mixing chamber 43 is provided at its one upper end with an inlet 43a and at its other lower end with an outlet 43b. The inlet 43a is connected to the outlet of the check valve 37. A steam feed line 45 opens into the cavity 39 at at least one steam supply opening and is preferably provided with a steam distributor which opens into the hollow space 39 when there are several steam supply openings distributed over the wall of the chamber 43. The steam feed line 45 is connected, for example, via a valve to a part 47a of a steam source 47. The already mentioned, possibly existing steam inlet of the chamber 23 of the conveying and / or pressing device 21 can be connected to a part 47b of the steam source 47 via a steam feed line 46, for example having a valve. This has at least one boiler and possibly at least one pump in order to generate steam - namely overheated and tensioned water vapor - and to feed it into the cavity 39 and possibly into the interior 27. The cavity 39 is still connected to a feed device 49. This has a reservoir 53 for storing a crosslinking agent 51 and possibly a reservoir 59 which serves for storing a diluent and / or solvent and / or dispersion agent 57 for the crosslinking agent 51. The feed device 49 also has a metering device 55 which is formed, for example, by at least one pump and two valves and has at least one feed line opening into the cavity 39. The feed system 1, the conveying and / or pressing device 21, the steam source 49 and the feed device 49 together form feed means around the cavity 39 different materials, in particular the starch and / or at least one material containing starch derivative as well as water and / or alcohol feed. The Chamber 43 can possibly also be provided with a normally closed safety pressure relief valve, for example a rupture disc.

The outlet 43b of the cavity 39 is connected to a line 61 which is closed in cross section and which has a heating and cooling device 63 and a thermal insulation and through which the flowable, gelled starch mixture formed in the cavity 39 can be pressed out of the cavity 39. The end of the line 61 facing away from the cavity 39 forms an outlet 71 of the part of the device used to form and gel the starch and / or at least one starch derivative mixture. The outlet 71 is designed, for example, as a slot die, but may also have an outlet opening that is circular in cross section.

Arranged after outlet 71 is a system for molding, drying and solidifying the gelled mixture, which flows out of outlet 71. The system has conveying and / or shaping means which are formed by a rolling device with a plurality of rolls 73, namely heated calender rolls arranged in pairs. It should be noted that two pairs of such rollers 73 are shown schematically in FIG. 1, but that more or fewer such rollers may also be present as required. Arranged after the rollers 73 is a dryer 75, which has a carrier 77 consisting of a glass plate and permeable to infrared light and two infrared light emitters 79, 81, one of which is mounted below the carrier 77 and the other above it, and separated from the carrier 77 by a free space. Furthermore, after the dryer 75 there are conveying means 83 which, for example, also consist of at least one pair of rollers. During operation of the device, the metering devices 11, 13 feed the mixer 15 from the reservoir 3 and from the reservoir 7 a material 5 or water 9 consisting of starch. For example, 25 kg of starch, for example moist, no, or at most only a little .mylose, potato starch with a water content of approximately 20% by weight and additionally 0.5 kg of water are continuously added per batch. It should be noted here that the feed to the mixer 15 can also take place continuously instead of in batches. The moist starch is mixed in the mixer 15 with the additional water. The starch / water mixture 91 formed in the mixer, which can also be regarded as a dispersion, is preferably fed continuously through the metering device 17 to the inlet 19 of the conveying and / or pressing device 21 and passes through this into the interior 27 of the chamber 23.

The rotating screw forming the conveying and / or pressing member 30 conveys the mixture 91 in the interior 27 from the inlet 19 to the outlet 29 and compresses and homogenizes the mixture. The mixture 91 is heated by the conveying, pressing and compression process and heated or cooled with the heating and cooling device 33, so that the mixture 91 in the interior 27 is less than 60 ° C. and for example 40 ° C. to 50 ° C has a temperature. The resulting pasty material is pressed through the outlet 29 and through the check valve 37 into the cavity 39. Via the feed line 45 the hot starch material is added for gelation and mixing, the steam being supplied from the steam source part 47a at a temperature of preferably 150 ° C to 200 ° C and for example 160 ° C to 190 ° C. The feed device 49 feeds the crosslinking agent 51 to the cavity 39. The crosslinking agent 51, for example melamine resin, is metered by the metering device 55 and continuously the starch in the cavity 39 fed. Depending on the water content of the starch in the cavity and on the type of crosslinking agent 51 to be added, the crosslinking agent can also be added, for example, with diluent and / or solution and / or dispersion agent 57 consisting of water. The mixture containing water, starch and crosslinking agent and contained in the cavity 39 is heated and gelled therein by the steam to a temperature above the temperature in the interior 27 of the conveying and / or pressing device 21, the steam cooling slightly can. The temperature of the mixture in cavity 39 can be, for example, about 150 ° C to 180 ° C. Furthermore, the steam and the mixture pressed into the cavity 39 through the inlet 43a generate a pressure in the cavity which is above the atmospheric pressure in the vicinity, the absolute value of which is expediently 0.3 MPa to 2.5 MPa and namely typically about 0. Is 8 MPa to 1.2 MPa. Since the steam gives off energy to the mixture, some of the steam in the cavity can possibly condense to liquid water. This can also be absorbed by the gel formed in the cavity. However, the remaining, preferably the largest part of the steam supplied remains in the cavity 39 preferably as steam - ie in the gaseous state.

In order to ensure optimal mixing, the starch mixture can be mixed during the gelation by the stirrer 41 rotatably arranged in the cavity 39. The stirrer 41 is designed and driven in such a way that, in comparison to the compression and the gravitational forces generated by the conveying and / or pressing member 30 consisting of a screw, it produces at most a small compression and at most small gravitational forces . Furthermore, the stirrer 41 also produces no or, in comparison, only a screw, at most a very small and in any case no inevitable conveyance. By the auε a conveying and / or pressing device 21 consisting of a screw press and the pressure generated by the water vapor in the cavity 39, the flowable, gelled starch mixture through the outlet 43f of the cavity 39 is continuously through the line 61 closed in cross section and to the For example, outlets 71 consisting of a slot die are pressed out.

In devices for large-scale production, the system used to form, dry and solidify the mixture, comprising the rollers 73 and the dryer 75, may be relatively far away from the gelling and / or mixing device 38, so that the line 61 may be up to can be several meters long. With the help of the heating and / or cooling device 63, the gelled mixture flowing through the line 61 can be brought to a temperature which is favorable for further processing and shaping and which depends on the composition of the mixture and the type of further processing. If, for example, a relatively thin film is to be produced, it is advantageous if the mixture from the outlet 71 is fed to the first pair of rollers 73 used for further processing at a temperature, for example, of about 60 ° C. to 70 ° C. If a relatively thick film is to be produced, the temperature mentioned can be lower and be, for example, about 40 ° C. to 55 ° C. or up to 60 ° C. If the mixture cools down to such a temperature in the range from 40 ° C. to 70 ° C. when the line 61 is passed through, the vapor contained in the mixture can condense to liquid water. However, this water is then at most still bound to a small extent by the mixture consisting of a gel and can drip out of the outlet 71 when the mixture flows out. If necessary, line 61 and / or outlet 71 can also be used with a water separator and / or water collector (not shown) for separating and / or Collect the water not bound by the gel.

The mixture which flows out of the outlet 71, is moist and soft and forms a web and / or a strand, is then fed continuously to the heated rollers 73 and rolled through it to form a web 95 which forms a film with a flat cross section. This web is already somewhat dried during the rolling and is then transported over the carrier 77 of the dryer 75 consisting of a glass plate and between the two emitters 79, 81. The web 95 or film is irradiated from below through the glass plate and from above with infrared light and thereby further dried and solidified. The conveying means 83, which have at least one pair of rollers, pull the web through the dryer 75 and transport it further, and they can also smooth the web. The now dry, flexible web 95 or film forming the object produced can then be wound up on a roll or further processed in some way in order to form, for example, bags, pockets or wall parts of a container. The film 95 can be pore-free and, for example, translucent and even completely transparent and crystal-clear. However, if a dye or the like is added to the mixture when it is introduced into the conveying and / or pressing device 21 and / or through the feed device 49 in the cavity 39, a tinted, only partially transparent or an opaque film can also be produced.

If the film to be produced is to be waterproof and, for example, also very thin and also transparent, a starch or a starch derivative which contains a lot of amylose can be added to the mixture to be gelled, as already mentioned in the introduction contains. For this purpose, for example, part of the potato starch fed from the feed system 1 through the inlet 19 to the interior 27 of the conveying and / or pressing device 21 can be replaced by amylose-rich corn starch or an amylose-rich corn starch derivative. The material supplied through the inlet 19 should then preferably contain relatively little water. For example, it is favorable if the water content - based on the weight of the material introduced through the inlet 19 into the interior 27 of the conveying and / or pressing device 21 - is at most 10% by weight and, for example, about 5% by weight to 8% by weight .% is. If the starting material containing, for example, potato starch and corn starch already has a water content that lies above the previously specified, favorable range, no water is supplied to the mixer 15 from the reservoir. If necessary, the starting material can even be dried before being introduced into the interior 27. The relatively dry grains or other particles of starch and / or a starch derivative can then be ground and reduced in size in the beginning part of the interior 27 of the screw press forming the conveying and / or pressing device 21. The mixture can possibly remain in this relatively dry state up to the outlet 29 and until it enters the cavity 39. The for

In this case, the amount of water required for gelling can only be supplied to the material in the cavity 39 in the form of the water vapor supplied by the steam source 47 and / or in liquid form from the supply device 49.

However, there is also the possibility of dispensing liquid material into the material in the last half that it has passed through, namely for example in the last third of the elongated interior 27 of the conveying and / or pressing device 21 via the metering device 14 and / or possibly alcohol and / or even better to supply water vapor and / or possibly alcohol vapor from part 47b of steam source 47 via steam feed line 46. In the area of the cavity 27 which extends from the mouth of the inlet 19 to approximately the mouth of the steam feed line 46 - at least in the first half and for example at least or approximately in the first two thirds of this cavity 27 - the temperature of the mixture rich in amylose can be similar as the temperature of the low amylose mixture is less than 60 ° C. In the end region of the interior 27 extending from the confluence of the steam feed line 64 to the outlet 29, the mixture can then have a higher temperature, which may be more than 60 ° C. However, the amount and temperature of the steam introduced into the interior 27 through the steam feed line 46 is preferably such that the temperature of the mixture is lower in the end region of the interior 27 than later in the cavity 39. The temperature of the mixture is in the end region of the interior 27 of the conveying and / or pressing device 21, preferably less than 140 ° C. and, for example, about 100 ° C. to 130 ° C. As a crosslinking agent, the mixture with the aid of the feed device 49 in the cavity 39 is preferably - as already mentioned in the introduction - glucose and melamine resin and / or melamine and / or urea added.

The device partially shown in FIG. 2 has a gelling and / or mixing device 138 with a gelling and / or mixing chamber 143 delimiting a cavity 139, the inlet 143a connected to a conveying and / or pressing device (not shown) and an outlet 143b and in which a stirrer 141 is arranged. The cavity 139 is also via a steam feed line 145 with a steam source 147 and with a feed device corresponding to the feed device 49 149, of which only a part of the feed line is shown. These parts and the parts not shown in FIG. 2 can be of the same or similar design as in the device described with reference to FIG. 1. The device shown in FIG. 2 differs from the device according to FIG. 1, among other things, in that the outlets 143b are sealed with a steam separator 165 through the line 161, which is closed in cross section and provided with a heating and / or cooling device 163 connected is. This is provided with an overpressure valve arranged on its ceiling, preferably manually adjustable, forming a steam outlet 167 and has an opening in its bottom, which is connected to an outlet 167, which is designed, for example, as a pouring head and / or slot die. The conveyor and / or casting belt 171 is arranged under the outlet 169. A shaping tool 173 consisting of a knife-like scraper, the distance of which from the belt 171 can preferably be adjusted, is arranged above this - in relation to its conveying direction - after the outlet 169. Furthermore, conveying means 175 and a shaping device 177 are present. This has a die 181 delimiting a mold cavity 179, the edges of which surround the mold cavity and span a plane and are preferably provided with an elastically deformable, for example, possibly rubber-elastic seal 182. The shaping device also has a pressing part 183, which can be pressed against the die 181 with an adjusting device or raised by the latter. Furthermore, there is a suction and blowing device 185 with at least one opening opening into the mold cavity 179.

During operation of the device shown in part in FIG. 2, the cavity 139 can continuously enter from its gelling and / or mixing device 138 through the inlet 143a Starch and / or material containing at least one starch derivative can be supplied. This can be gelled analogously in the cavity 139 with the supply of a crosslinking agent and steam, as was explained in the description of FIG. 1. The resulting mixture can then be pressed through the line 161, the steam separator 165 and the outlet 169 onto the conveyor belt and / or casting belt 171. When passing through the steam separator 167, the mixture is preferably so hot that the steam supplied to it in the cavity 139 is still partly in a gaseous state in the steam separator and that the mixture has a relatively high, for example 80 ° C. to 120 ° C. ° C flows out of the outlet 169 and reaches the conveyor and / or casting belt 171. The mixture can be used to achieve a favorable

The temperature in the steam separator 165 and, when flowing out of the outlet 169, can be heated or cooled in the line 161 with the heating and / or cooling device 163 if necessary. In the steam separator 165, at least part of the steam present in the mixture escapes via this

Pressure relief valve of the steam outlet 167. The pressure relief valve in the cavity of the steam separator 165 maintains a pressure which is higher than the atmospheric pressure in the environment and which presses the gelled mixture out through the outlet 169. The mixture flowing continuously from the outlet 169 onto the conveyor and / or casting belt 171 is transported away from the outlet 169 by the belt. The shaping tool 173 smoothes the mixture, which still forms a readily deformable web 195, and brings it to an adjustable layer thickness. The preformed, sheet-like web 195 is then fed to the shaping device 177 by the transport means 175. The pressing part 183 is first lifted off the die 181. When the web 195 covers the mold cavity 179, the pressing part 183 is pressed against the die 181 and thereby presses the web 195 against the mold Seal 182 indicates that the web seals mold cavity 179 tightly from the environment. A vacuum is now created in the mold cavity with the suction and blowing device 185. The section of the web 195 located in the shaping device 177 is thereby shaped into a spatial, for example container and / or shell-shaped molded part 197. After this shaping, the pressing part 183 is lifted off the die 181. The molded part 197 can then be ejected from the mold cavity 179 by an air blast generated by the suction and blowing device 185. The section of the web 195 located in the forming device 177 temporarily comes to a standstill for the forming process. However, the mixture can nevertheless be continuously led out of the outlet 169 and processed into a web 195, the web 195 then temporarily, for example during the shaping process between the conveyor and / or casting belt 171 and the shaping device 177, a loop which serves to compensate can form. With the cutting means arranged in relation to the transport direction at or after the forming device 177, the finished molded parts 197 can be separated from the web. The molded parts 197 produced can have a relatively small wall thickness in comparison to their size and, for example, as

Containers for food, such as vegetables, fruits, milk products, meat and the like are used. If necessary, the containers can be closed with a flat film after the introduction of the ¹ -food. Otherwise, the molded parts can be made transparent, clear and colorless or only translucent, tinted or opaque, as desired.

The device that is partially visible in FIG. 3 is designed and has the same or similar design as the device described with reference to FIGS. 1 and 2 inter alia a gelling and / or mixing device 238 with a cavity 239 bounded by a gelling and / or mixing chamber, an inlet 243a, an outlet 243b and a stirrer 241 arranged in the cavity 239. However, the chamber here has a horizontal axis around the the

Stirrer 241 is rotatable. The inlet 243a is in turn connected to a conveyor and / or pressing device, not shown. The cavity 239 is also in turn connected via a steam supply line 245 to a steam source 247 and to a line of a supply device 249. The outlet 243b is connected via a line 261 provided with a heating and / or cooling device 263 to the inlet 266 of a steam separator 265, which has a steam outlet 267 with a pressure relief valve and an outlet 269 for the gelled mixture. The device according to FIG. 3 also has a centrifugal casting device 271 with a rotor which can be rotated by a drive device (not shown). The rotor carries at least one casting mold 273 and, for example, a plurality of casting molds 273, the or each casting mold being fastened detachably and interchangeably. The outlet 269 of the steam separator 265 is connected to the inlet of the centrifugal casting device 271 via a line and a shut-off device shown as a valve. This inlet can be formed, for example, by a rotary leadthrough or rotary coupling that seals the connection between the gas separator and the centrifugal casting device tightly against the surroundings, so that the mixture can still be pressed into the casting device with an air pressure above the surrounding area. However, the inlet of the pouring device can also be open to the environment, so that the pressure of the mixture when flowing into the centrifugal casting device is approximately equal to the ambient air pressure.

When operating the part shown in FIG. the device containing a starch and / or a starch derivative is gelled continuously in the cavity 239 and then pressed through the steam separator 265 and fed to the centrifugal casting device 271. The temperature of the mixture in the steam separator should in turn be so high that a large part of the steam supplied in the cavity 239 and not bound by the gelled mixture is still in a gaseous state and steam can be discharged through the steam outlet 267. When producing non-porous objects, such as translucent moldings or hollow bodies, by means of the centrifugal casting device 271, the gelled mixture pressed out of the outlet 265 is introduced into the at least one mold 273 via the valve mentioned. In this device, the centrifugal force is used to produce molded parts from the mixture containing starch, the speed of rotation having to be so great that gravity is eliminated. Depending on the design and arrangement of the molds used, full or hollow shapes can be produced. At the end of a casting operation, the shut-off device present between the outlet 269 and the centrifugal casting device 271 is temporarily closed during the removal of the molded parts. The steam separator 265 may possibly not only serve to separate steam, but also as a buffer or expansion tank for the gelled mixture in order to intermittently discharge the mixture continuously supplied to it from the cavity 239. However, there is also the possibility of providing a separate buffer or expansion tank after the steam separator. Furthermore, the outlet 269 can be connected to a branch with two or more branch lines, each of which has a shut-off device and is each connected to a centrifugal casting device. In this case, the vapor from the cavity 39 can be separator 265 supplied mixture are alternately fed to the various centrifugal casting devices. The gelled mixture can flow out at least approximately continuously from the outlet of the steam separator and be introduced alternately in succession into different centrifugal casting devices.

The device partially shown in FIG. 4 is partially identical or similar to the devices described with reference to FIGS. 1 to 3 and has a line 361 which is provided with a heating and / or cooling device 363 and the cavity one Gelling and / or mixing device, not shown, connects to the inlet 366 of a steam separator 365. This has a steam outlet 367 with a pressure relief valve and an outlet 369 for the gelled mixture. Furthermore, a rotatable, preferably heatable centrifuge 371 is connected to the outlet 369 of the steam separator 365 via a shut-off device shown as a valve. This centrifuge 371 has a chamber 373, the wall 375 of which has a plurality of hair nozzles 377, through which the gelled mixture is pressed out when the centrifuge is rotating, so that several threads 395 are formed at the same time. These threads can be dried by hot air treatment and, for example, braided and / or twisted into a cord and / or a rope. However, there is also the possibility that a cotton-like product is formed from the threads 395, so that filler material or packaging material can be used. In this case, at least one mineral salt, for example in the form of slate dust, stone dust, ceramic dust, phosphate acid and / or calcium carbonate, is preferably added to the starting material at the latest in the cavity of the gelling and / or mixing device. Instead of a heated centrifuge for producing the threads 395, there is also the possibility of a stationary tool serving as a shaping tool Use multi-hole nozzle. The gelled mixture is pressed and / or sucked through the multi-hole nozzle, so that several threads are created at the same time.

The device partially shown in FIG. 5 is largely the same or similar to the device described with reference to FIGS. 1 to 4 and in particular has a conveyor and / or pressing device, not shown, which has an extruder or screw press with a chamber and in the interior of which an axis rotatable, serving as a conveying and / or pressing member, is formed. A gelling and / or mixing device 438 has a gelling and / or mixing chamber 443 which delimits a cavity 439 and has an inlet 443a and an outlet 443b. At least one stirrer 441 of an agitator is arranged in the cavity 439. The outlet of the conveyor and / or pressing device, not shown, is connected to the inlet 443a via a check valve, also not shown. A steam source 447 is connected to the latter via a steam feed line 445, a valve and preferably via a steam distributor with a plurality of openings opening into the cavity 439. Furthermore, a feed device 449 designed similarly to the feed device 49 is connected to the cavity 439 and has, for example, a reservoir 453, a reservoir 459 and a dosing device with at least one pump and valves. In the reservoir 453 is a mixture chert 451 Gespe ^i, the εowohl a crosslinking agent and contains a propellant. Furthermore, the reservoir 453 can also be provided with a rotatable mixing tool (not shown) in order to homogeneously mix the said components of the mixture 451 with one another. The reservoir 459 in turn contains a diluent and / or solution and / or dispersant 457, which for example contains water or possibly additionally or instead of this alcohol. The outlet 443b of the gelling and / or mixing chamber 443 is connected via a line 461 provided with a heating and / or cooling device 463 to the inlet 466 of a steam separator 465, which has a steam outlet 467 with a pressure relief valve and an outlet 469 for the

Mixture. This is designed, for example, as a casting head with an outlet opening which is circular in cross section or as a slot die and opens into a groove 471. In order that the mixture pressed out of the cavity 439 to the outlet 469 during operation between the outlet 443 of the cavity 439 and the outlet 469 is as little as possible foams, the line 461 should be as short as possible. If space is possible, the outlet 443b may possibly be connected practically directly to the steam separator 465. Likewise, the outlet opening of the outlet 469 should be as close as possible to the steam separator 465. However, the connection that connects the gelling and / or mixing chamber 443 to the steam separator 465 is intended to form a constriction between the cavities of the chamber and the steam separator, i.e. transverse to the flow direction of the mixtures have a narrower cross section than the two cavities mentioned, so that they are delimited from one another. The channel 471 passes through a dryer 473 which has a microwave radiator 475. The bottom of the trough 471 can possibly also be provided with conveying means, not shown, for example at least one conveyor belt and / or conveyor roller.

During operation of the device partially shown in FIG. 5, the inlet (not shown) of the conveyor and / or pressing device consisting of a screw press is charged, for example, with the same or a similar material as was explained for the device according to FIG . The material introduced into the screw press should in particular still contain no blowing agent and preferably also no crosslinking agent. The material is homogenized in the screw press by the rotating screw forming the conveying and / or pressing member to a pasty mass. This is then added in cavity 439 to a crosslinking agent, for example melamine resin and a blowing agent, namely citric acid or another mixture containing 451, the amount of blowing agent being, for example, approximately 1% by weight of the mixture formed in cavity 439 . The various components of the mixture are homogeneously mixed with one another in the cavity 439 analogously to the previously described devices and gelled under the action of the steam supplied from the steam source 447. The gelled mixture - ie the material containing starch and / or a starch derivative and a propellant - is then pressed into the steam separator 465 by the pressure generated by the screw and by the steam, in which at least a large part of it in the mixture existing steam is derived. The mixture or the flowable material then passes through the outlet 469 into the channel 471. There the mixture or the material comes into contact with the ambient air and can expand freely. The mixture can - depending on its flowability and the dimensions of the outlet 469 and the channel 471 - be more or less shaped by the outlet and / or the channel, so that the channel may serve as a casting mold to some extent. The mixture or the material then moves in the channel in the form of a viscous liquid and / or a semi-solid strand into the dryer 473 and is heated therein by the microwaves generated by the microwave radiator 475. The material containing a blowing agent foams and solidifies into a solid object, namely a porous foam sheet 495, which can still be separated into pieces, for example. The conveying and / or pressing devices designed as screw presses can be loaded with the material to be processed in all the devices described with reference to FIGS. 1 to 5 in such a way that they can be homogenized continuously. In the same way, the materials in all of these devices can be pressed continuously through the cavity of the gelling and / or mixing chamber and thereby gelled therein.

The methods which can be carried out by means of the various devices enable economical production of objects or products based on starch and, in particular, can also be carried out largely or completely automatically without any problems.

The devices and methods can still be modified in various ways. For example, features of various described devices and methods can be combined with one another.

Furthermore, the gelling and / or mixing chamber can, for example, also be provided with a heating device which has, for example, a heating coil or an electrical heating element. The mixture contained in the chamber and flowing through it can then be heated both by the steam supplied and by the heating device.

The gelling and / or mixing chamber may possibly be provided with fixed baffles or the like instead of with a rotating stirrer in order to ensure thorough mixing of the starch pressed through the chamber and / or a starch derivative as well as material containing water and / or alcohol to cause components supplied to the chamber. Possibly the line arranged between the conveying and / or pressing device and the gelling and / or mixing chamber can be omitted, so that the pasted material pressed out of the interior of the conveying and / or pressing device directly into the cavity of the gelling and / or mixing chamber.

If a non-porous web or film is to be produced that has a relatively large thickness, the dryer having infrared light emitters can possibly be omitted from the device shown in FIG. 1. The web or film can then possibly be dried exclusively by the heated rollers 175 or by them and by a warm air dryer.

The device for the production of porous foam products partially shown in FIG. 5 and its operation can be modified such that the crosslinking agent and the blowing agent are stored in separate reservoirs, then dosed by at least one dosing device and by a common one Line or through εeparate lines are fed to the cavity of the gelling and / or mixing chamber.

The conveying and / or pressing device 21 may possibly consist of a screw or extruder press of a different type of device which is suitable for containing the starch and / or at least one starch derivative as well as water and / or alcohol while overcoming the steam to press the pressure generated in the cavity of the gelling and / or mixing chamber into it. The conveying and / or pressing device can, for example, be designed in the manner of pumps as are known for pumping sludge and other dispersions. The device can possibly also be designed for injection molding. In this case, the outlet of the gelling and / or mixing chamber via the steam separator or without an intermediate steam separator and / or via a compensating valve and buffer container can be connected to a screw or screw piston or piston press which is suitable to intermittently press or inject the mixture formed in the cavity into a casting mold.

However, the conveying and / or pressing device 21 consisting of a screw press for injection molding can also be operated intermittently or replaced by a screw screw press. In this case, the starch and / or a starch derivative as well

Material containing water and / or alcohol is then pressed intermittently through the cavity of the gelling and / or mixing device.

Claims

PATENT CLAIMS

1. A method for producing a starch and / or a product containing at least one starch derivative, a

Material with starchy biomass and / or starch and / or at least one starch derivative is gelled in a cavity (39, 139, 239, 439), characterized in that the material in the cavity (39, 139, 239, 439) water vapor and / or alcohol vapor is supplied.

2. The method according to claim 1, characterized in that the heating of the material in the cavity (39, 139, 239, 439) is carried out at least in part and, for example, completely by the ampf and that material in the cavity (39, 139, 239, 439 ) is heated to a temperature which is at least 80 ° C. and at which the steam supplied remains at least in part and for example at least for the most part in the gaseous state.

3. The method according to claim 1 or 2, characterized gekenn¬ characterized in that the material in the cavity (39, 139, 239, 439) is under a pressure which is greater than the ambient air pressure and preferably at least 0.15 MPa and, for example 0.3 MPa to 2.5 MPa.

4. The method according to any one of claims 1 to 3, characterized in that at least a part, for example the largest part, of the supplied steam is removed from the material in a still vaporous state.

5. The method according to claim 4, characterized in that the gelled material in the cavity (39, 139, 239, 439) through a steam separator (165, 265, 365, 465) through to an outlet (71, 169, 269, 369, 469) and / or to at least one casting mold (273), and daεs at least a portion of the steam previously supplied to it in the cavity (39, 139, 239, 439) is withdrawn from the material in the steam separator (165, 265, 365, 465), the material in the steam separator (165, 265, 365, 465) being preferred - Wisely kept under a pressure that is greater than the ambient air pressure.

6. The method according to any one of claims 1 to 5, characterized in that a cross-linking agent (51) is added to the material in the cavity (39, 139, 239, 439).

7. The method according to any one of claims 1 to 6, characterized in that the material comprising biomass and / or starch and / or at least one starch derivative with a conveying and / or pressing device (21) into the cavity (39, 139, 239, 439) and heated to a temperature in the latter which is above the temperature of the material in the conveying and / or pressing device (21).

8. The method according to claim 7, characterized in that the material is introduced into an elongated inner space (27) of the conveying and / or pressing device (21) and is conveyed by a screw along the inner space (27) and the material is in the minimum the first half of the interior (27) and, for example, the entire interior (27) is kept at a temperature which is less than 60 ° C.

9. The method according to claim 7, characterized in that material is introduced into an elongated interior (27) of the conveying and / or pressing device (21) and is conveyed by at least one screw along the interior (27) and that the material in the last passed half of the interior (27) of water vapor and / or alcohol vapor.

10. The method according to any one of claims 1 to 9, characterized in that the material in the cavity (39, 139, 239, 439) is moved with at least one stirrer (41, 141, 241, 441).

11. The method according to any one of claims 1 to 10, characterized in that the material is assembled, shaped and dried in such a way that the product produced forms at least one pore-free and / or translucent and, for example, even transparent and crystal-clear object.

12. A method for producing a starch and / or at least one starch derivative product, in particular according to claim 11, wherein a material with starch-containing biomass and / or starch and / or at least one starch derivative gelled in a cavity and then formed into at least one object is characterized in that the object after the shaping is at least partially dried by irradiation with infrared light.

13. The method according to any one of claims 1 to 12, characterized in that the material after molding is at least partially dried with hot air passed past it and / or with heated rollers (73, 175).

14. The method according to any one of claims 1 to 13, characterized in that the starch and / or the at least one starch derivative has at least 0.3% by weight and preferably at least 1% by weight amylose, that the material at the latest in the cavity (39 , 139, 239, 439) glucose and urea and / or melamine and / or melamine resin is added and that the material in the cavity (39, 139, 239, 439) is at a temperature of at least 140 ° C and for example at least 150 ° C is heated.

15. The method according to any one of claims 1 to 14, characterized in that the mixture gelled in the cavity (39) is continuously formed into a web (95, 195) which forms a film with a flat cross section.

16. The method according to claim 15, characterized in that the web (195) is formed by reshaping at least one spatial molded part (197), for example a container.

17. The method according to any one of claims 1 to 14, characterized in that several threads (395) are simultaneously formed from the flowable material gelled in the cavity.

18. The method according to claim 17, characterized in that at least one mineral salt, for example in the form of slate dust, stone dust or ceramic dust, and / or phosphate acid and / or calcium carbonate, is added to the material used to form the threads (395) and that a cotton-like product is formed from the threads (395).

19. The method according to any one of claims 1 to 13, characterized in that the material gelled in the cavity is sprayed in a flowable state onto a surface of a body in order to coat and / or impregnate this surface with the product.

20. A process for producing a starch and / or a product containing at least one starch derivative, in particular according to one of claims 1 to 19, wherein a material with a starch-containing biomass and / or starch and / or at least one starch derivative in a cavity is gelled, characterized in that the material is admixed with polyethylene oxide at the latest during the gelling, or that polyethylene oxide is applied to a surface of an object formed using the material.

21. A process for producing a starch and / or at least one product containing a starch derivative, in particular according to one of claims 1 to 20, wherein a material with starch-containing biomass and / or starch and / or at least one starch derivative is gelled in a cavity, characterized in that that material is formed into an object and that at least one area forming a surface of the object is provided with a metallic layer.

22. The method according to claim 20 or 21, characterized in that the surface of the object is provided with at least one pattern which has depressions whose depths and / or spacings are at most 0.01 mm.

23. The method according to any one of claims 1 to 10, characterized in that a blowing agent is added to the material in the cavity (439) and that the flowable, gelled material formed in the cavity (439) is led out of the cavity (439), is foamed and dried so that the product produced is porous.

24. A method for producing a starch and / or at least one starch derivative containing product, in particular according to claim 23, wherein a material with starch-containing biomass and / or starch and / or at least one starch derivative is gelled in a cavity, characterized in that the Product for Foaming and / or drying is heated with microwaves.

25. The method according to claim 23, characterized in that the gelled, flowable material formed in the cavity is sprayed into a hot air stream, so that the material forms drops when sprayed and these expand in the hot air stream into porous grains.

26. The method according to claim 23, characterized in that the gelled, flowable material formed in the cavity is applied to a flat heated surface and formed into at least one foamed plate.

27. The method according to any one of claims 23 to 26, characterized in that the blowing agent (451) comprises at least one of the following materials: salt, cement, acid, hydrogen peroxide, aluminum oxide, the salt, for example, from a metal carbonate, such as lime or calcium carbide , consists.

28. The method according to any one of claims 23 to 27, characterized in that natural, water-soluble gelatin is added to the material at the latest in the cavity as an extender.

29. A process for producing a starch and / or at least one product containing a starch derivative, in particular according to one of claims 23 to 27, wherein a material with starch-containing biomass and / or starch and / or at least one starch derivative is gelled in a cavity, characterized in that that acetyl anhydride and / or sodium acetate and / or cellulose diacetate is added to the material at the latest in the cavity.

30. The method according to any one of claims 1 to 29, characterized in that magnesium sulfate is added to the material at the latest in the cavity.

31. The method according to any one of claims 1 to 30, characterized in that at least one cellulose-containing substance, for example sawdust, sawdust, straw or paper, is supplied to the material in the cavity at the latest.

32. Method according to one of claims 1 to 31, characterized in that plastic particles, preferably consisting of polyvinyl chloride and / or polyethylene, are added to the material at the latest in the cavity.

33. Device for performing the method according to one of claims 1 to 32, with a cavity (39, 139, 239, 439) delimiting chamber (43, 143, 243, 443) and with supply means (1, 21, 47, 49 , 147, 149, 247, 249, 447, 449) in order to supply the cavity (39, 139, 239, 439) with starchy biomass and / or starch and / or at least one starch derivative, characterized by one with the chamber (43, 143 , 243, 443) connected steam source (47, 147, 247, 447), in order to gell the material present in the cavity (39, 139, 239, 439) water vapor and / or alcohol vapor into the cavity (39, 139, 239, 439 ) to initiate.

34. Device according to claim 33, ch ^r dadu gekenn¬ lines, the supply means dasε one with a Einlaεε (43a, 143a, 243a, 443a) of the chamber (43, 143, 243, 443) associated conveying and / or Preεεvorrichtung (21) a rotatable screw.

35. Device according to claim 33 or 34, characterized in that a steam separator (167, 267, 367, 467) is present, one of which is sealed with an outlet (143b, 243b, 443b) of the cavity (139, 239, 439) connected inlet (166, 266, 366, 466), an outlet (169, 269, 369, 469) for gelled material and a steam outlet (167 , 267, 367, 467) has been and is designed to extract steam from the material fed to it during operation from the cavity (139, 239, 439) and passed through it, the steam outlet having, for example, a pressure relief valve.

36. Device according to one of claims 33 to 35, characterized by an agitator with at least one rotatable stirrer (41, 141, 241, 441) arranged in the cavity (39, 139, 239, 439).

37. Device according to one of claims 33 to 36, characterized by a dryer (75, 473) to generate infrared light or microwaves or hot air and thus to dry at least one object formed from the material.