EP1252229A1

EP1252229A1 - Composition for producing biologically degradable shaped bodies and method for producing such a composition

Info

Publication number: EP1252229A1
Application number: EP01911476A
Authority: EP
Inventors: Anneliese Kesselring; Thomas KÖBLITZ
Original assignee: APACK AG fur biologische Verpackungen
Current assignee: APACK AG fur biologische Verpackungen
Priority date: 2000-01-11
Filing date: 2001-01-11
Publication date: 2002-10-30
Also published as: WO2001051556A1; DE10000774A1; AU2001240504A1; CA2396982A1; CN1395597A

Abstract

The invention relates to a dry mixture, which comprises starch, biologically degradable fiber material, protein and, optionally, additives, for producing biologically degradable shaped bodies, and to a method for producing such a dry mixture. The invention additionally relates to a paste that can be baked, whereby this paste comprises starch, biologically degradable fiber material, protein, water and, optionally, additives. Finally, the invention relates to shaped bodies that are produced by using said dry mixture or said paste that is capable of being baked.

Description

Composition for the production of biodegradable moldings and method for producing such a composition

The invention relates to a dry mixture and a bakable mass for the production of biodegradable moldings and methods for producing such a dry mixture or bakable mass. The invention further relates to moldings produced from this dry mixture.

Packaging materials are produced in large quantities in industry, trade and in the household. For example, fast food chains sell large quantities of food such as hamburgers, French fries, bratwurst etc. as well as hot and cold drinks in plastic packaging such as packaging based on polyethylene, polypropylene, polystyrene, etc. Plastic-based packaging is also widely used in retail. For example, fruit is pre-portioned for sale in plastic trays. Furthermore, for example, apples or peaches are also transported and offered in carriers provided with hemispherical depressions. For example, an apple or a peach is placed in each hemispherical recess. These carriers are increasingly made of plastic.

The aforementioned plastic containers made in the form of cups, plates, cups, bowls, boxes and carriers of all types have the advantage that they are light in weight. A light weight of these containers is advantageous with regard to the transport costs incurred, both when transporting the unfilled containers themselves and when transporting goods stored in these containers, such as fruit.

The containers made of plastic are regularly disposed of after being used once. Due to the wide range of applications and the large number of pieces in which these containers are used regularly, these containers lead to a considerable amount of waste. It is extremely disadvantageous that these containers made of plastic have an extraordinary longevity. There are currently essentially two methods for disposing of these plastic containers.

In the first method, the plastic containers contained in the waste are burned in a waste incineration plant. This approach is disadvantageous. On the one hand, the manufacture of plastic containers is based on the consumption of petroleum, ie a non-renewable source of raw materials. Furthermore, this procedure requires construction of further waste incineration plants or the greater use of existing waste incineration plants. In the course of increasing environmental awareness, however, the construction of new waste incineration plants can hardly be implemented today. In this respect, there are increasing disposal difficulties with regard to the steadily growing amount of waste.

In the second method, the plastic containers are reprocessed as the starting material for new plastic containers to be produced. This offense, however, first requires a single-variety production of the plastic container and finally after the use of the plastic container, a complex separation of the container depending on the type of plastic used. Since the plastic containers are still used in particular for fast food chains, the containers must be cleaned of food waste, fat, ketchup, etc. after use. However, such a procedure is complex and costly, so that the used containers are regularly incinerated in a waste incineration plant in accordance with the above-mentioned method.

In view of the disadvantages associated with plastic containers, attempts have been made for some time to produce biodegradable containers which can be used as plates, cups, trays, carriers, etc. in the above-mentioned uses.

Shaped bodies based on starch are known in the prior art which are partially or completely biodegradable.

PCT / EP95 / 00285 (WO 96/23026) discloses a process for the production of moldings in which a viscous mass of biodegradable fiber material, water and starch is baked in a baking mold to form a fiber-starch composite. Waste paper, recycled material or biodegradable fiber material is used as fiber material, which is previously shredded while being crushed. The proportion of starch to water in the viscous mass is preferably 1: 3 to 1: 2. The baking time can be varied between 0.5 and 15 minutes, it being stated that shorter cycle times in the range from 1 to 3 minutes are generally sufficient. However, if the amount of water in the baking mass is increased, a baking time between 4 and 12 minutes is required to get good results: The disadvantage is that in order to achieve shorter baking times, the water content in the baking mass must be reduced, so that ultimately larger amounts of starch and fibers are used per molded article produced.

For economic reasons, it is necessary for mass-produced products such as the moldings in question here, for example for use in fast food restaurants, that they can be produced inexpensively. In this respect, short manufacturing times and lower material consumption are of crucial importance for a manufacturer in order to successfully survive on the market with its products.

US 5,607,983 discloses a method for producing a biodegradable molded body. Short vegetable fibers, vegetable fiber powder, gelling material, water, blowing agent and auxiliary agents are stirred into a dough and then heated at a temperature of 10 ° C to 200 ° C for 2 to 3 minutes and then for 20 minutes at a temperature of 120 ° C dried.

On the one hand, it is disadvantageous that a blowing agent must be used in this process, and on the other hand that the production time is very long. Both the additional use of a blowing agent and a total manufacturing time

22 to 23 minutes per molded article allows economical production of such

Shaped body as a mass article not too.

WO 95/04104 discloses a process for producing an essentially biodegradable polymer foam, wherein thermoplastic or destructurized starches, a biodegradable hydrophobic polymer and a biodegradable fibrous or capsule-like material which has the ability to bind water capillary-active are mixed , This process is complex since, in a first step, thermoplastic starch must be mixed with fiber saturated with water in a precisely defined temperature and pressure range, it being essential that the water bound in the fiber by capillary action is not released. The foam is then produced in a second step, in which both the temperature and the pressure are increased, so that the water bound in the fiber is released to foam the starch. With regard to the temperature and pressure ranges to be observed exactly, this requires

Process a complex process management.

From DE 40 09 408 AI it is known that a dough can be produced from cellulose-containing and protein-containing materials and water, which is then shaped and then baked to provide a rotting, disposable item. The disposable article produced by this process consists of a protein structure in which cellulose is embedded.

It is disadvantageous that the disposable articles produced in this way must have a thick wall of about 0.5 cm for reasons of stability. The production of thin-walled moldings e.g. in the form of cups, mugs, bowls, bowls, etc. with acceptable quality is not possible. Furthermore, for reasons of stability, it is not possible to use lightweight carriers for fruit, such as for apples, peaches, etc. according to this procedure.

Due to the thick walls, increased use of materials is also required. These thick walls also require longer baking times of around three to ten minutes and an increased baking temperature of around 250 ° C. With the method known from DE 40 09 408 AI, no high-quality moldings can be produced. Furthermore, in view of the increased use of materials, this method is not suitable for producing a high-quality mass-produced item inexpensively.

A method for dispersing cellulose-containing fibers in water is known from EP 0 683 831 B1. This method allows the use of interconnected cellulosic fibers, such as e.g. exist in paper material. With a solids content of up to 80%, an aqueous dispersion of cellulose-containing fibers hydrocolloids, such as Starch, vegetable or animal protein, added under strong mechanical action to provide a highly viscous mass in which the cellulose-containing fibers are torn apart and distributed in the viscous mass. It is necessary to use enough hydrocolloid to bind all of the water. Corn starch is regularly used as the hydrocolloid.

It is disadvantageous that the production of a shaped body from the highly viscous mass prepared by this process involves increased material consumption due to the high solids content. Thus, the use of this highly viscous mass does not allow inexpensive production of molded articles, which is extremely disadvantageous in particular in the production of mass articles. Furthermore, the moldings produced from this viscous mass have an increased weight, which ultimately leads to increased transport costs for the moldings produced. The object of the present invention is to provide a composition for the production of a biodegradable shaped body which allows a reliable and inexpensive production of high quality biodegradable shaped bodies. In particular, there is a need for a composition that enables a reduction in manufacturing time and a reduction in the amount of material used. There is also a need for a method of making such a composition.

The object of the present invention is achieved by a dry mixture, which comprises starch, biodegradable fiber material and protein and optionally additives, for the production of biodegradable moldings.

For the purposes of the invention, the term “dry mixture” is understood to mean a free-flowing composition, for example in the form of a powder or granules. It is not necessary that the dry mixture according to the invention be absolutely dry. The dry mixture can, for example, have a residual moisture content of about 5 to about 14% by weight, preferably below 9% by weight

For the purposes of the invention, the term “starch” is understood to mean natural starch, chemically and / or physically modified starch, technically produced or genetically modified starch and mixtures thereof. Starch can be used as starch from corn, for example corn, waxy maize, wheat, barley, rye, oats, millet, rice, etc. or cassava or sorghum. Of course, the starch contained in legumes such as beans or peas or the starch contained in fruits such as chestnuts, acorns or bananas can also be used. The starch contained in roots or tubers can also be used.

Potato starch is particularly suitable in the present invention. The potato starch advantageously contains one phosphorus ether group per 200 to 400 anhydroglucose units. The negatively charged phosphate groups are linked to the C6 position of the anhydroglucose unit. In the production of a bakable mass from the dry mixture according to the invention, the negatively charged phosphate groups, by mutual repulsion, detangle the individual potato amylopectin molecules. Due to the mutual repulsion of the negatively charged phosphate groups, the branches of the amylopectin molecules are largely unfolded or stretched out. This presence of esterified phosphate groups results in a high viscosity of potato starch-water mixtures. The term "biodegradable fiber material" means in particular vegetable and animal fibers. For the purposes of the invention, cellulose-containing fibers are preferably used as vegetable fibers. Cellulose-containing fibers are fibers of any kind that contain cellulose or consist of cellulose. Animal fibers are so-called protein fibers such as wool, hair or silk.

Vegetable fibers that can be in different lengths and widths are particularly preferably used. In particular, plant fibers are used which have a length in the range from approximately 50 μm to approximately 3000 μm, preferably from approximately 100 μm to approximately 2000 μm, further preferably from approximately 150 μm to approximately 1500 μm, more preferably from approximately 200 μm to approximately 900 μm , most preferably from 300 μm to about 600 μm. The width of the plant fibers can be in a range from approximately 5 μm to approximately 100 μm, preferably from approximately 10 μm to approximately 60 μm, particularly preferably from approximately 15 μm to approximately 45 μm. The fibers are mainly made from wood, hemp or cotton. Such fibers can be produced in a manner known to the person skilled in the art. . ■ ' ^■ "• •

The term "protein" is understood to mean biopolymers based on amino acids. All so-called proteinogenic amino acids, i.e. the amino acids usually involved in protein building, as well as the so-called non-proteinogenic amino acids, which are usually not involved in protein building.

According to the invention, the term “protein” is also understood to mean peptides or polypeptides. The term "protein" in the context of the invention also includes naturally occurring protein, chemically modified protein, enzymatically modified protein, recombinant protein, protein hydrolyzates or mixtures thereof. The protein can be of vegetable or animal origin.

The dry mixture according to the invention, which comprises starch, biodegradable fiber material and protein, surprisingly enables the baking time to be shortened by up to 35%, preferably up to 50%. Furthermore, the use of protein in the dry mixture according to the invention enables a reduction in the material requirement in the production of moldings by up to 10% by weight to 20% by weight.

The dry mixture according to the invention can be stored extremely advantageously over a long period of time without causing a noticeable change in the Composition is coming. This advantageously allows prefabrication and storage of the dry mix. In this respect, it is possible, for example, to provide the dry mix according to the invention to subcontractors of a manufacturer of biodegradable moldings and thus to ensure that the moldings produced by the subcontractor are of the desired quality. Since the dry mixture according to the invention only has to be mixed with water or gelatinized starch at the subcontractor, only the transport costs for the dry mixture are incurred, ie there is no transport of the water to be added.

In order to produce biodegradable moldings, the dry mixture according to the invention is first mixed with the addition of water to form a bakable mass or a dough. The bakable mass produced from the dry mixture according to the invention differs from the baking masses known in the prior art in that it is creamier, foamy and more voluminous and thus has a lower density. To produce a certain volume of bakable mass, less material is thus required when using the dry mixture according to the invention, compared to a dry mixture which does not comprise any protein.

To produce a biodegradable molded body, a certain volume of bakeable mass (baking mass, dough) is placed in a baking mold. These baking tins are known from the wafer baking technique. Since a certain volume of bakeable mass is filled into such a baking mold, the increased volume of the bakeable mass based on the dry mixture according to the invention thus leads to a reduction in the material requirement. Since the moldings produced using the dry mixture according to the invention are produced in very large numbers, a reduction in the material requirement by up to 10% by weight to 20% by weight means an enormous reduction in costs.

Furthermore, the use of a bakable mass based on the dry mixture according to the invention leads to a reduction in the baking time required in the production of a shaped body.

In the context of the invention, “baking time” is understood to mean the time which lies between the closing of the baking mold, which takes place after the baking mold has been filled with the bakable mass, and the opening of the baking mold for removing the baked molded body. The baking time is reduced by up to 50% when using a bakable mass based on the dry mixture according to the invention. The reason for the reduction in baking time is not clear. However, the inventors suspect the following:

Because of the larger volume of a bakeable mass produced on the basis of the dry mixture according to the invention, less weight of bakeable mass is added to the baking mold. The lower amount of bakable mass naturally also contains less water, which must evaporate during the baking process. It is therefore assumed that there is a connection between the reduction in the amount of bakable mass to be baked and the shorter baking time.

In addition, the inventors have found that a molded article produced with the dry mixture according to the invention inside the baked molded article, i.e. has larger and more uniform pores or capillary structures in the interior of the walls of the shaped body, that is to say, for example, in the base, cover and side areas. These larger pores or capillaries enable an easier water / water vapor escape compared to shaped bodies which were produced using a dry mixture without protein. It is therefore assumed that there is a connection between the larger pores or capillaries and the shorter baking time.

In view of the larger and more uniform pore structure within the walls of the conventional shaped body, the weight of the shaped body produced is further reduced by up to 20%. A weight reduction of up to 20% is extremely advantageous when transporting the molded bodies.

Furthermore, the molded body produced using the dry mixture according to the invention has a more closed surface. A more closed surface is particularly advantageous with regard to the thermal insulation ability of the molded body. Furthermore, a more closed surface results in a better and more reliable rejection of, for example, moisture or grease into the walls or the bottom of the molded body.

According to a preferred embodiment, starch, biodegradable fiber material and / or protein are fixed to one another in the dry mixture according to the invention. For the purposes of the invention, the term “fixed to one another” is understood to mean that the components of the dry mixture according to the invention, ie starch, biodegradable fiber material, protein and any additives added, adhere to one another with and without the use of an adhesion promoter.

For example, starch and biodegradable fiber material can be fixed to one another. Starch and protein or biodegradable fiber material and protein can also be fixed to one another. Starch, biodegradable fiber material and protein are preferably fixed to one another. Furthermore, it is possible that the additives added are additionally fixed in each of the possibilities specified above. In other words, according to the invention, all possible combinations of fixations between the components used are possible.

A separation of the dry mixture according to the invention is thus extremely advantageously prevented. For this purpose, it may be sufficient that only starch and the biodegradable fiber material are fixed to one another. Such segregation could occur, for example, during transportation by truck or railroad due to the regularly occurring vibrations, provided, for example, that the biodegradable fiber material and the starch are not fixed to one another. The risk of segregation depends heavily on the particle and / or fiber sizes used.

Further explanations with regard to the implementation of the fixation are given in the comments on the method for producing the dry mixture according to the invention.

The dry mixture according to the invention is preferably in the form of granules.

The term "granules" is understood to mean an accumulation of granules. A granulate is an asymmetrical aggregate of powder particles. It has no harmonious, geometric shape. The shape of a sphere, a stick, a cylinder etc. is only approximate and indicated. The surface is usually uneven and jagged, the mass in many cases more or less porous. The so-called fluidized bed process is often used to produce granules.

The provision of the dry mixture according to the invention as granules advantageously allows simple filling and handling of the dry mixture according to the invention. In particular, a granulate according to the invention is present Dry mixture can be easily metered, which is extremely advantageous when automating a process for producing biodegradable moldings.

The starch contained in the dry mixture according to the invention is preferably native starch. Native starch is in granular form by the wet grinding of starchy raw materials, such as. B. Get grain, tubers and roots. Since the starch is already in the form of granules, it is very easy to produce the dry mixture according to the invention as granules.

According to a preferred embodiment, the protein is selected from the group consisting of naturally occurring protein, chemically modified protein, enzymatically modified protein, recombinant protein, protein hydrolyzates and mixtures thereof.

The dry mixture according to the invention preferably contains about 0.5 to about 12% by weight, particularly preferably about 2 to about 10% by weight and most preferably about 4 to about 8% by weight of protein.

However, the amounts of protein contained in the dry mixture according to the invention can vary depending on the protein or protein mixture used. However, it is easily possible to determine an optimal amount of the protein to be added for each dry mixture by a few tests within the ranges given above.

For example, proteins of animal origin such as actin, myoglobin, myosin, hemoglobin, collagen, elastin, immunoglobulins, keratins, fibroin, conchagens, ossein, albumins, caseins, FPC (fish protein concentrate) can be used as proteins.

Prolamines such as e.g. Gliadin, Secalin, Hordein, Zein and corn and soy protein can be used.

Vegetable proteins such as Soy, corn, pea, lupine, millet protein have been found to be very suitable for the purposes of the invention. Soy protein is particularly preferably used. Soy protein is extremely cheaply available in large quantities.

According to a preferred development of the invention, hydrophobic proteins are used as proteins. Hydrophobic proteins are characterized by a high proportion uncharged amino acids in the amino acid sequence. In particular, these proteins contain high proportions of glycine, alanine, valine, leucine, isoleucine, phenylalanine, tryptophan, proline and methionine, all of which give the protein a hydrophobic character.

It is clear to the person skilled in the art that the proteins listed above are only an exemplary selection to illustrate the invention. Of course, other proteins or protein mixtures can also be used. An important criterion is that the price of the protein or protein mixture to be used is low in view of the very large numbers of moldings to be produced.

According to a preferred embodiment of the present invention, the protein is selected from the group consisting of casein, alkali caseinate, alkaline earth caseinate, casein hydrolyzate and mixtures thereof.

Casein is extremely advantageous and caseinates can be obtained in large quantities at an acceptable price: With regard to the biodegradable moldings to be produced in large quantities from the dry mixture according to the invention, it is essential that the protein used in the dry mixture according to the invention is inexpensive. You can get about 1 kg of casein from 30 liters of skim milk.

The casein is used regularly in the form isolated from milk. It is of course also possible to use the α, β and γ subunits of casein separately or in certain combinations thereof.

Casein which can be used according to the invention is commercially available as acid casein from the company BMI-Landshut.

The dry mixture according to the invention preferably contains about 1 to about 10% by weight, particularly preferably about 2 to about 8% by weight and most preferably about 3 to about 7% by weight of casein.

Vegetable protein, preferably soy protein, is more preferably present in the dry mixture according to the invention in an amount of about 0.5 to about 10% by weight.

The casein can be used as such or as an alkali caseinate or alkaline earth caseinate. Calcium caseinate has proven to be particularly useful. Calcium caseinate which can be used according to the invention is commercially available as Caseinato Di Calcio from the company BMI-Landshut.

The dry mixture according to the invention preferably contains about 1 to about 10% by weight, particularly preferably about 2 to about 8% by weight and most preferably about 3 to about 7% by weight of calcium caseinate.

According to a further preferred embodiment of the invention, the dry mixture according to the invention can comprise further additives. These additives make it possible to influence the properties of the biodegradable molded article produced from the dry mixture according to the invention. For example, hydrophobicizing agents, whitening agents, food colors, flavorings etc. can be contained in the dry mixture as additives.

In this case, it has proven to be particularly advantageous to adhere one additive or several additives to influence the product properties of the shaped body on the starch. The adhesive application of additive. Starch advantageously prevents a possible separation of additive and starch during the transport of the dry mixture according to the invention. The dry mixture according to the invention preferably contains up to 10% by weight, preferably 0.3 to 5% by weight, particularly preferably 0.9 to 1.8% by weight of additive.

For the purposes of the invention, the term “additive” encompasses any compounds which are suitable for influencing the product properties of the shaped body. These additives are preferably completely or essentially completely biodegradable. Preferred examples of these additives are hydrophobizing agents, whitening agents, colorants, food colors, flavorings, etc.

Hydrophobizing agents are constituents which impart hydrophobic properties to the shaped body produced from the dry mixture according to the invention. Whiteners are compounds that are used to lighten the color of the moldings. For example, blue dyes are used as dyes, which are used, for example, for coloring fruit bowls or fruit carriers. The following blue dyes can be used, for example: natural colors or lacquered colors. Green dyes are also used, for example, which are used for coloring shells to hold plants. The following green dyes can be used, for example: natural colors or lacquered colors. Food colors are dyes used to color the packaging of food. For the purposes of the invention, any aroma substance, in particular biodegradable aroma substance, which, for example, gives the shaped body produced from the dry mixture according to the invention a specific smell and / or taste, can be used as the aroma substance.

A particularly preferred example of hydrophobizing agents are fluoroalkyl polymers, the term "fluoroalkyl polymers" indicating that they are polymers which are composed of, in particular, repeating alkyl units, it being possible for one or more, possibly even all, hydrogen atoms to be replaced by fluorine atoms. For example, a hydrophobizing agent based on a perfluoroalkyl acrylate copolymer can be used.

The whitening agent can be a compound with at least one disulfone group. Such compounds are well known to those skilled in the relevant technical field. An example of such a disulfonic acid compound is 4,4'-bis (1,3,5-triazinylamino) stilbene-2,2'-disulfonic acid.

The object on which the invention is based is further achieved by a bakable composition which comprises starch, biodegradable fiber material, protein and water and, if appropriate, additives.

The term "bakable mass" is understood to mean a baking mass or a dough which is used in baking devices known from wafer baking technology, such as e.g. Baclczangen can be baked to form a shaped body. The bakeable mass is, for example, placed in a heated baking mold of such a known baking device, whereupon the bakeable mass is distributed in the baking mold and fills it completely. The bakeable mass present in the baking pan releases water or water vapor when exposed to heat, which emerges from the baking pan through the provided outlet channels. During this process, the bakeable mass is solidified, providing the desired shaped body.

The bakable mass can be prepared from the dry mixture according to the invention by adding water and, if appropriate, additives, if these are not already present in the dry mixture, with mixing, for example stirring or kneading. Preferably the bakable mass contains from about 3% to about 15%, preferably from about 5% to about 10%, most preferably from 7.8% to about 9.8% by weight. -% biodegradable fiber material, preferably cellulose-containing fibers.

Furthermore, the bakable composition preferably contains from about 6% by weight to about 30% by weight, preferably from about 10% by weight to about 20% by weight, most preferably from about 16.1% by weight to about 20.05 % By weight native starch.

Furthermore, the bakable composition preferably contains from about 2% by weight to about 10% by weight, preferably from about 4% by weight to about 8% by weight, most preferably from about 5.4% by weight to 6.8 % By weight pre-gelatinized starch.

Furthermore, the bakable composition preferably contains from about 45% by weight to about 90% by weight, preferably from about 60% by weight to about 80% by weight, more preferably from about 60% by weight to about 75% by weight , most preferably from about 63% to about 71% by weight water.

Protein in the bakable composition according to the invention is preferably in an amount of up to 10% by weight, preferably up to about 5% by weight, more preferably about up to 3% by weight of protein, most preferably up to about 2% by weight. -% contain.

The bakable mass preferably contains 0.5 to 10% by weight of vegetable protein. Vegetable proteins such as Soy, corn, pea, lupine, millet protein have been found to be very suitable for the purposes of the invention. Soy protein is particularly preferably used. Soy protein is extremely cheaply available in large quantities. More preferably, the bakable mass contains 1 to 2% by weight of vegetable protein, preferably soy protein.

The above data in percent by weight are based in each case on the total weight of the bakable mass.

Pre-gelatinized starch can be from about 90 to about 99.9% by weight of water and about 0.1 to about 10% by weight of native starch, more preferably from about 95% by weight of water and about 5% by weight of native Starch. A starch suspension is first produced from these two components. This starch suspension can then be heated and then cooled to give pregelatinized starch. The heating is preferably carried out to a temperature at which the aqueous suspension of starch granules changes into a paste-like form. This temperature is also known as the Kofler gelatinizing temperature. The Kofler gelatinization temperature is between 56 and 66 ° C for potato starch and between 62 and 72 ° C for corn starch. The suspension is kept in this temperature range, for example, over a period of about 10 minutes. The pre-gelatinized starch is then cooled. The temperature to which it is cooled is preferably about 50 ° C or less.

The above description for the production of pre-gelatinized starch is only to be understood as an exemplary production process. Of course, those skilled in the art are aware of other methods of making pregelatinized starch that can be used in the present invention. For example, the starch suspension or slurry can also be gelatinized with steam in a so-called jet cooker.

According to an advantageous development, the biodegradable fiber material consists of cellulose-containing fibers. It is further preferred that the starch is native starch. Furthermore, the bakable mass preferably contains protein which is selected from the group consisting of naturally occurring protein, chemically modified protein, enzymatically modified protein, recombinant protein, protein hydrolyzates and mixtures thereof. The protein is preferably selected from the group consisting of casein, alkali caseinate, alkaline earth caseinate, casein hydrolyzate and mixtures thereof. The alkaline earth caseinate calcium caseinate is particularly preferred.

For further explanation, reference is made accordingly to the respective statements regarding the dry mixture according to the invention.

The bakable mass according to the invention can of course also be produced without using the dry mixture according to the invention. The respective individual components, ie starch, biodegradable fiber material, protein and optionally additives, can be mixed with water in any order to prepare the bakable composition according to the invention. For example, a dough can first be made from starch, biodegradable fiber material and water, to which protein and optionally additives are then added. The object on which the invention is based is further achieved by the use of protein for the production of a dry mixture or a bakable mass for the production of biodegradable moldings. Furthermore, the object is achieved by a shaped body which has been produced using the dry mixture according to the invention or the bakable composition according to the invention.

The dry mixture according to the invention is excellently suitable for the production of biodegradable moldings.

Water is added to the dry mixture according to the invention, which comprises starch, biodegradable fiber material and protein and optionally further additives, and mixed until a bakeable mass is obtained.

A bakable mass is preferably characterized by a homogeneous distribution of all components and a viscosity required for the respective purpose. The viscosity of the bakable mass can be adjusted via the proportion of water added to the dry mixture consisting of starch, biodegradable fiber material and protein and optionally additives. The viscosity of the bakable mass which is preferably to be set for the particular molded article to be produced can be determined by a few experiments. Depending on the shape, the size and the respective wall thickness of the molded body to be produced or the size of the baking mold used in each case for baking the molded body, it may be advantageous to adjust the viscosity of the baking mixture accordingly.

The baked mass produced is then baked. For this purpose, the bakable mass is placed in a baking mold and heated in a closed baking mold at a temperature of preferably about 100 ° C. to about 200 ° C., particularly preferably at about 150 ° C.

The baking pan is designed depending on the shape of the desired end product, for example in the form of a bowl or a cup. The baking mold can be formed by at least two baking plates, ie an upper and a lower baking plate, which are accommodated in a baking tongs, the inner surface of the baking plates being kept spaced apart in a closed, locked state of the baking mold to form a mold cavity. The mold cavity is then filled by the bakeable mass. The baking mold has specially shaped evaporation openings for discharging the water vapor. For the simultaneous production of a plurality of moldings, a plurality of Baking tongs are used. Such baking devices are based on the waffle baking technology known per se.

The duration of the baking process is essentially determined by the size of the shaped body to be baked and by the wall thickness of the shaped body set in each case. The baking time is usually between 10 s and approximately 100 s, preferably approximately 30 s to approximately 80 s, more preferably 60 s to 70 s.

The object of the invention is further achieved by a method for producing the dry mixture according to the invention (first embodiment), wherein

(a) starch, biodegradable fiber material and protein are mixed;

(b) an aqueous solution is sprayed during mixing; and

(c) the mixture obtained in step (b) is dried.

Furthermore, the object of the invention is achieved by a method for producing the dry mixture according to the invention (second embodiment), wherein

(a) starch and biodegradable fiber material are mixed; (b) an aqueous protein-containing solution is sprayed in during mixing; and (c) drying the mixture obtained in step (b).

According to the invention, the term “aqueous solution” means water or a water-based solution such as, for example, protein-containing aqueous solution, pregelatinized starch, protein-containing pregelatinized starch, additive-containing aqueous solution, etc.

In this method, in step (b), pre-gelatinized starch is preferably additionally sprayed in during the mixing.

The fixing of, for example, starch and biodegradable fiber material to one another can be brought about by spraying water, for example, during the mixing of starch, biodegradable fiber material and protein and drying the mixture. The water preferably evaporates shortly after it has come into contact with the starch, the biodegradable fiber material and the protein. That is, water is added in an amount and over a sufficient period of time so that the surface of the starch particles or granules is made slightly sticky. The biodegradable fiber material, for example cellulose fibers, then remains on the surface of these "tackified" starch particles. as well as the protein stick. It is of course also possible that the protein, as soon as it comes into contact with water, acts as a kind of adhesive and fixes starch and biodegradable fiber material together. Of course, both effects can also occur simultaneously.

According to the second embodiment, an aqueous protein-containing solution is sprayed in instead of water during the mixing of starch and biodegradable fiber material. In this second method, too, starch, biodegradable fiber material and protein are fixed to one another in accordance with one another. The components are fixed to one another via the same effects as in the first embodiment described above.

By spraying in an aqueous protein-containing solution, starch particles and the biodegradable fiber material stick together. Furthermore, spraying in an aqueous protein-containing solution causes the starch particles or the biodegradable fiber material to be coated with the protein-containing solution and the starch particles or the biodegradable fiber material to become the carrier material for the protein.

Furthermore, starch which has already been gelatinized instead of water can be sprayed in as an aqueous solution and thus fixation of starch, biodegradable fiber material and protein can be achieved. The pre-gelatinized starch preferably has a temperature of less than 50 ° C. Of course, both water and pre-gelatinized starch can be sprayed in one after the other or simultaneously.

In the second embodiment of the method according to the invention, it is possible to spray an aqueous protein-containing solution and pregelatinized starch in succession or simultaneously. Furthermore, it is also possible to introduce the protein directly into the pre-gelatinized starch and then to spray the protein-containing, pre-gelatinized starch during the mixing of biodegradable fiber material and starch.

The mixture for producing the dry mixture according to the invention can be dried, for example, in a warm environment, for example in a warm air stream. However, further drying techniques well known to the person skilled in the art can also be used. Mixing in the methods according to the invention (embodiment 1 or 2) according to step (b) and drying according to step (c) are preferably carried out in a common step by swirling in a fluidized bed in a warm air stream.

The aqueous or aqueous protein-containing solution and, if appropriate, the pregelatinized starch are particularly preferably sprayed in a fluidized bed system in which starch and biodegradable fiber material are swirled in a warm air stream. Here too, the pre-gelatinized starch can be sprayed in before, after or simultaneously with the aqueous or aqueous protein-containing solution. Of course, a previously prepared, possibly protein-containing, pregelatinized starch can also be sprayed into the fluidized bed. The solutions are preferably sprayed in from spray nozzles which are arranged above the fluidized bed.

The use of a fluidized bed reactor in which starch, biodegradable fiber material and optionally protein are swirled in a warm air stream is particularly advantageous when the dry mixture according to the invention is to be provided as dry granules. In the fluidized bed produced by the warm air stream, the water introduced with the aqueous or aqueous protein-containing solution and the optionally pasted starch which has been sprayed in evaporates very rapidly. Biodegradable fiber material, starch particles and protein are fixed to one another by evaporation of the water in the fluidized bed. A dry mixture according to the invention is thus provided extremely advantageously, in which no separation of starch, biodegradable fiber material and protein can take place.

The temperature of the warm air stream in the fluidized bed system is preferably about 40 ° C. to about 90 ° C., preferably about 50 ° C. to about 70 ° C. As stated above, the aqueous or aqueous protein-containing solution and optionally pregelatinized starch can be sprayed in via the spray nozzles arranged above the fluidized bed.

Furthermore, the additives mentioned above can also be sprayed in the form of aqueous solutions. Depending on the properties of the molded article to be produced, the additives can be combined accordingly and sprayed in simultaneously or in succession with the aqueous or aqueous protein-containing solution and, if appropriate, the pregelatinized starch. It is also possible to spray a pre-gelatinized starch sprayed in at a temperature of about 50 ° C. with a grease-containing release agent. The fat-containing release agent can, for example, consist predominantly of fat and furthermore contain at least one component selected from the group consisting of oil, wax and lecithin. Beeswax is preferably used as the wax.

Furthermore, commercially available fat-containing release agents such as premixes can of course also be used. Premix is a mixture of wholly or partially unhardened vegetable fats and can be obtained from I.C.L. VAN DER ZON in Essen can be obtained under item number HC 2000.

Vegetable fats and oils have generally proven themselves as release agents. However, synthetic fats and oils can also be used. The release agent is preferably selected from the group consisting of soybean oil, palm fat and mixtures thereof. The concentration of release agent is preferably 0.05 to 0.7% by weight, more preferably 0.1 to 0.2% by weight, in each case based on the bakable composition. These release agents can be sprayed in together with pregelatinized starch and / or protein-containing solution, for example a soy protein solution.

The fat-containing release agent can, however, also be added in a separate operation to the baking composition itself or during the preparation of the baking composition from the dry mixture according to the invention. Of course, it is also possible to put the fat-containing release agent directly into the baking mold immediately before the baking process.

The following examples serve to further explain the invention.

To produce a bakable mass, native starch and cellulose fibers were placed in a fluidized bed system on a Conidur floor with an area of 1862 cm ² (26.6 cm x 70.0 cm). The total dumping height was approximately 225 mm. Potato starch (powdered goods) with a moisture content of approximately 16% by weight was used as the native starch. Cellulose fibers with a length of approximately 600 μm and a width of approximately 30 μm were used as the biodegradable fiber material.

The native potato starch and the cellulose fibers were mixed dry in a fluidized bed. Warm air with a Temperature of about 70 ° C and a volume flow of 480 m ³ / h passed through the starch-cellulose fiber mixture to produce a fluidized bed.

Pre-gelatinized starch was sprayed from above the fluidized bed at a spray rate of 65 g / min for 5 minutes through two nozzles, each with a nozzle diameter of 0.8 mm and a spray pressure of 1.2 bar. The temperature of the sprayed solution of pre-gelatinized starch was below 50 ° C.

The product obtained was a granulate in which starch and cellulose fibers are evenly connected to one another. (The product temperature was 42 ° C and the product moisture was 8.6% by weight.)

The granules thus produced were mixed with water so that the concentration ranges given below were set:

The baked mass indicated above was portioned and, as indicated below, with the appropriate proportions of protein, i.e. Casein or calcium caseinate added. The protein was homogeneously distributed in the proportions given below in the bakable mass by mixing.

To determine the reduction in baking time, moldings were then baked out in the same baking mold, the bakable mass or the dough being used with and without added protein. The baking time was determined by determining the time from the closing of the baking mold after the bakable mass had been added to the baking mold until the opening of the baking mold to remove the baked molded article.

The amount of casein added in% by weight is based on 100% by weight of the above-mentioned bakeable mass. The baking time reduction in percent was calculated by referring to the time by which the baking time was reduced in absolute terms to the baking time of the comparison mixture without the addition of protein.

The results shown below were obtained. Table 1: Casein addition to the dough (baking mass)

Table 2: Calcium caseinate addition to the dough (baking mass)

The data in% by weight calcium casein addition and the information regarding the reduction in baking time were determined as stated above.

It turns out that when using calcium caseinate, a significant reduction in the baking time can be achieved.

Since the moldings are mass-produced, a baking time reduction of, for example, 25% with the addition of 1.0% by weight of calcium caseinate is an economically very important improvement of the process. Furthermore, since not only the baking time is reduced to a considerable extent, but also the material requirement is reduced by up to 10% by weight to 20% by weight, the invention represents a significant advance in the field of the production of biodegradable moldings.

When soy protein is used instead of casein or caseinate, comparable advantageous effects are achieved. In view of being soy protein is cheaper than casein or caseinate, soy protein is preferably used as a protein additive in the production of large amounts of biodegradable moldings. The bakable mass preferably contains 0.5 to 10% by weight, more preferably 1 to 2% by weight, of soy protein.

In addition, the biodegradable moldings produced with the addition of protein also have better thermal insulation properties with regard to the more uniform pore structure.

The biodegradable moldings produced by this process have a residual moisture content of about 6% by weight after the baking process, which increases to about 10% by weight residual moisture after storage of the moldings at ambient humidity. Setting a residual moisture content of about 10% by weight has proven to be advantageous with regard to the flexibility of the molded articles produced. It has been shown that a residual moisture content of about 10% by weight makes the moldings more flexible.

The biodegradable molded body according to the invention produced from the dry mixture according to the invention can be produced extremely advantageously inexpensively while significantly reducing the baking time and reducing the material requirement. Furthermore, the biodegradable moldings produced using the dry mixture according to the invention have excellent properties with regard to breaking strength, elasticity, insulation capacity and surface quality.

The more closed surface of the moldings according to the invention also enables a more reliable application of moisture and grease repellent barrier layers, for example in the form of biodegradable films. These films can be applied to the baked molded article from polyester, polyester amide or polylactic acid. It has been shown that the adhesive properties of the shaped body produced using the dry mixture according to the invention are improved when barrier layers are applied in the form of films, for example by means of the deep-drawing process.

Using the dry mixture according to the invention or the bakable mass according to the invention, inexpensive high-quality, “biodegradable moldings can be produced. For example, the moldings according to the invention can have wall thicknesses of about 1.6 to 1.8 mm. Of course, moldings with thinner wall thicknesses such as for example from about 0.8 to about 1.4 mm or thicker wall thicknesses such as from about 2.0 to about 3.2 mm.

The moldings are made extremely advantageously from renewable raw materials and can be completely or essentially completely biodegraded. In this respect, the dry mix or bakeable mass according to the invention does not fall under the "Green Dot" system created in Germany for the disposal of packaging. That , A manufacturer of the above-mentioned shaped articles in the form of packaging material does not have to make the mandatory contributions to the "Green Dot" disposal system for conventional packaging.

The moldings produced from the dry mixture or bakable mass according to the invention are almost completely biodegraded in a rent or in a compost heap within 10 to 14 days.

Claims

claims

1. Dry mixture comprising starch, biodegradable fiber material and protein and optionally additives for the production of biodegradable moldings.

2. Dry mixture according to claim 1, wherein starch, biodegradable fiber material and / or protein are fixed to one another.

3. Dry mixture according to one of the preceding claims, wherein the dry mixture is in the form of granules.

4. Dry mixture according to one of the preceding claims, wherein the biodegradable fiber material consists of cellulose-containing fibers.

5. Dry mix according to one of the preceding claims, wherein the starch is native starch.

6. Dry mix according to one of the preceding claims, wherein the protein is selected from the group consisting of naturally occurring protein, chemically modified protein, enzymatically modified protein, recombinant protein, protein hydrolyzates and mixtures thereof.

7. Dry mix according to one of the preceding claims, wherein the protein is selected from the group consisting of casein, alkali caseinate, alkaline earth caseinate, casein hydrolyzate and mixtures thereof.

8. Dry mixture according to one of the preceding claims, wherein the alkaline earth caseinate is calcium caseinate.

9. Baked mass which comprises starch, biodegradable fiber material, protein and water and optionally additives.

10. Baked mass according to claim 9, wherein the protein in the bakeable mass is contained in an amount of up to 10 percent by weight, preferably up to 5 percent by weight.

11. Baked mass according to claim 9 or 10, wherein the biodegradable fiber material consists of cellulose-containing fibers.

12. Baked mass according to one of claims 9 to 11, wherein the starch is native starch.

13. Baked mass according to one of claims 9 to 12, wherein the protein is selected from the group consisting of naturally occurring protein, chemically modified protein, enzymatically modified protein, recombinant protein, protein hydrolyzates and mixtures thereof.

14. Baked mass according to one of claims 9 to 13, wherein the protein is selected from the group consisting of casein, alkali caseinate, alkaline earth caseinate, casein hydrolyzate and mixtures thereof.

15. Baked mass according to one of claims 9 to 14, wherein the alkaline earth caseinate is calcium caseinate.

16. Use of protein for the production of a dry mixture according to one of claims 1 to 8 or a bakable mass according to one of claims 9 to 15.

17. Use of a dry mixture according to one of claims 1 to 8 or a bakable mass according to one of claims 9 to 15 for the production of moldings.

18. Shaped body, characterized in that the shaped body is produced using a dry mixture according to one of claims 1 to 8 or a bakable mass according to one of claims 9 to 15.

19. A method for producing a dry mixture according to any one of claims 1 to 8, wherein

(a) starch, biodegradable fiber material and protein are mixed;

(b) an aqueous solution is sprayed during mixing; and (c) drying the mixture obtained in step (b).

20. A method for producing a dry mixture according to any one of claims 1 to 8, wherein

(a) starch and biodegradable fiber material are mixed; (b) an aqueous protein-containing solution is sprayed in during mixing; and

(c) the mixture obtained in step (b) is dried.

21. The method according to claim 19 or 20, wherein in step (b) additionally pre-gelatinized starch is sprayed during the mixing.

22. The method according to any one of claims 19 to 21, wherein the mixing according to step (b) and the drying according to step (c) in a common step by swirling in a fluidized bed in a warm air stream.

23. Dry mix according to one of claims 1 to 6, wherein the protein is vegetable protein.

24. A dry mix according to claim 23, wherein the vegetable protein is soy protein.

25. Baked mass according to one of claims 9 to 13, wherein the protein is vegetable protein.

26. Baked mass according to claim 25, wherein the vegetable protein is soy protein.

27. Baked mass according to claim 26, wherein the baked mass contains soy protein in an amount of 0.5 to 10 wt .-%, preferably 1 to 2 wt .-%.

28. Baked mass according to one of claims 9 to 15 or 25 to 27, wherein the baked mass contains 0.05 to 0.7% by weight, preferably 0.1 to 0.2% by weight, of release agent.

29. Baking composition according to claim 28, wherein the separating agent is soybean oil and / or palm fat.