EP1090064A1

EP1090064A1 - Foamed thermoplastic film made from biodegradable materials

Info

Publication number: EP1090064A1
Application number: EP99923786A
Authority: EP
Inventors: Jürgen LOERCKS; Harald Schmidt
Original assignee: BioTec Biologische Naturverpackungen GmbH and Co KG
Current assignee: BioTec Biologische Naturverpackungen GmbH and Co KG
Priority date: 1998-06-17
Filing date: 1999-06-11
Publication date: 2001-04-11
Also published as: WO1999065977A1; AU4054199A

Abstract

The invention relates to a biodegradable and compostable semifinished product, moulded material or moulded article made from a foamed, cellular material having thermoplastic properties and which can therefore be further processed by means of hot shaping. The inventive semifinished product is obtained by introducing gaseous, low-boil pressurized expanding agents into the molten material and subsequent foaming process. The semifinished product can then be thermoplastically processed and used in multiple ways. Other advantages of the foamed moulded material and article are that they are biodegradable, compostable and have a low density that can result in considerable cost savings.

Description

Foamed, thermoplastic film made from biodegradable materials

The present invention relates to a foamed, thermoplastically processable, thermoformable and weldable semi-finished product or molding or molding consisting of a biodegradable and compostable material / polymer and a process for its production, which is characterized in that the biodegradable and compostable thermoplastic polymer in The extruder is converted into a melt, the melt is gassed with a low-boiling blowing agent directly under pressure, the blowing agent is incorporated into the melt, the melt-blowing agent mixture is cooled to the required molding temperature, extruded through a nozzle at the end of the extruder, and formed into a cellular semi-finished product or molding material or molded part is shaped and expanded, the foamed semi-finished product or molded part having a volume density many times lower than that of its framework substances and as a biodegradable and compostable polymer foam semi-finished product or molded part v is used.

Biodegradable foams are already known from a large number of documents that deal with the topic and also show how eminently important the realization of lightweight, fully biodegradable foam plastics is to be assessed. This is because packaging materials or insulating materials are to be made available which are completely biodegradable after use and are particularly light, material-saving, shock-absorbing and insulating due to a foam structure. WO95 / 04104 proposes a foamed, thermoplastic starch polymer which foams when processed by splitting off water by using fibers which bind capillary-active water.

WO94 / 05492 describes a biodegradable layered composite material on the basis of hardened starch foam, in which the starch foam is produced by water vapor in a syringe expansion process.

WO96 / 07693 discloses a molded part made of starch foam, which is produced by extruding starch into starch foam profiles and further processing into molded parts.

WO96 / 07539 in turn shows a sandwich panel with a starch foam core. Patent applications EP-B-0 413 798, EP-A-0 667 369, EP-A-0 696 611 and EP-A-0 696 612 deal with foamed starch-based materials.

WO83 / 02955 describes a process in which starch is processed in the presence of water and a blowing agent in an extruder at elevated temperature to form a foam product. EP 0 375 831 and EP 0 376 201 disclose starch foam products and processes for their production from starches containing high amylose.

EP 0 696 611, EP 0 667 369 and EP 0 696 612 deal with "loose fillers" based on starch and polymer blends with PVOH, EVOH, PVAc, PU, polyester. Packaging materials can also be produced from these "loose fillers" by agglomeration. A process for producing a foam based on starch is described in DE 23 04 736, the Starch is inflated under the influence of heat and a blowing agent mixture.

In DE 32 06 751, a starch foam is obtained by an extrusion process using blowing agents that release carbon dioxide. DE 23 65 523 also deals with starch foam.

Finally, CA-A-2 057 668 proposes a biodegradable polymer foam which, on the one hand, consists of 50% to 100% of one or more homopolymers, which are biodegradable, and from 0% to 50% of a polymer, which is hardly or is not biodegradable at all. The homopolymers are preferably polylactic acid or polymers based on a lactide. In particular, synthetic polymers, such as polyester, polycarbonate, polysulfone, etc., are mentioned as hardly or not biodegradable polymers, which makes the biodegradability of the proposed foam questionable.

In the aforementioned examples of the prior art, the foamed, biodegradable materials have significant disadvantages when used with foamed plastics such as EPS

(expanded polystyrene). Either the starch foams produced by extrusion or injection expansion cannot be processed further with the methods of the plastics processing industry due to the lack of thermoplastic processing properties, or foamed starch polymer blends are still far too heavy compared to the prior art, for example to foamed semi-finished products such as polystyrene films, so that is the purpose of the foaming process is not achieved. In many cases, the use of water or water As a blowing agent, serdampf creates a very uneven and open-pore foam structure, which has disadvantages and restrictions for use in food and non-food areas. The inventive feature of the compostability of the foam material is not always reliably achieved.

The invention has for its object to provide a biodegradable, compostable foam as a semifinished product or molding or molding with a uniform pore distribution and thermoplastic processing properties, for example as a thermally deformable, foamed film or injection molded foamed molding or molding, the manufacture of End products from the semi-finished product according to the invention with the usual methods of the plastics processing industry by thermoplastic forming, hot forming or deep drawing into biodegradable end products with versatile applications, for example for cups, plates, trays, cups, bowls, portion packs, blister backs, trays, packaging bowls for fruit, vegetables and fresh meat, egg packaging, protective films, sandwich elements, laminated foam films.

This object is achieved in connection with the preamble of claim 1 according to the invention by the characterizing features of claim 1. The foamed semi-finished product according to the invention, which has a particularly light density in the sealing range below 300 g / l, consists of biodegradable thermoplastic materials, which are preferably produced on the basis of renewable raw materials such as starch or cellulose and polymer mixtures based on starch or cellulose, from the melt Extrusion produced by continuously introducing a low-boiling blowing agent into the extruder Polymer melt is metered. Depending on the properties of the biodegradable polymers, the melt is gassed directly in the extruder at pressures of 150 - 400 bar. The melt / fuel mixture is then cooled in the extruder to the required molding temperature, continuously injected, molded and directly foamed. The melt-fuel mixture can also be injected into a mold and foamed therein.

Alternatively, it is also possible to first extrude, cool and granulate the melt / fuel mixture or to form it as a semi-finished granulate. These granules loaded with fuel or gas can then be foamed in a further separate process step to give molded parts in accordance with customary methods, or can be processed into foamed molded parts by means of hot air / hot steam.

The following can be used as biodegradable thermoplastic polymers:

- Aliphatic polyesters such as polylactide, polycaprolactone, bio-nolle, PHB-PHVB

- Copolyester from aliphatic and aromatic polymer building blocks

- polyester amides

- polyester urethanes

- Thermoplastic polysaccharides and derivatives thereof, such as chitin and its derivatives, cellulose derivatives and starch derivatives - Starch blends with the aforementioned, biodegradable polymers, as well

- Mixtures of the aforementioned materials.

Further suitable polymers can be found in the claims.

The following can optionally be proposed as cell formers:

- Mixture of citric acid and sodium bicarbonate

- azobicarbonamide

- inorganic fillers

- color pigments

The following are proposed as low-boiling, physical blowing agents:

- Aliphatic hydrocarbons, especially iso-pentane and n-pentane

- carbon dioxide

- nitrogen

Fluorocarbons as blowing agents or partially halogenated blowing agents are deliberately avoided in this area of application for reasons of environmental compatibility, although the technical function is suitable.

Nitrogen and / or carbon dioxide are used as a particularly preferred blowing agent, which take into account the special ecological balance advantages of biodegradable materials based on renewable raw materials such as starch as foam plastics. The biodegradable foam products are extruded in the extruder by direct gassing with the gaseous blowing agent into the polymer melt and continuous or discontinuous further processing in customized plant technology. The individual manufacturing processes are divided into sensible process steps, which are combined depending on the task.

For the production of the semi-finished products according to the invention in the form of uncoated and coated as well as laminated and non-laminated foam sheets and sheets, the method is used in which the shape and density of the product are achieved in one operation, regardless of the type of blowing agent. The extruder used is preferably a single-shaft extruder with a large cylinder length of approximately L / D 40: 1. The length of the extruder results from the process sequences and is designed for conveying and melting the granulated bioplastic raw material, mixing in the blowing agent and cooling the melt / blowing agent mixture to the molding temperature. The propellant is supplied by suitable, precise metering pumps with the necessary injection pressure while maintaining a constant

Volume into the polymer melt. Special shear and mixing profiles on the screw ensure that the components are evenly distributed.

The foamed semi-finished products are made from biodegradable polymers according to the principle of free expansion on the tool. For this reason, the BAW melt mixture is horizontally formed into a tube during film production. The foam film tube is then pulled over a temperature-adjustable calibration mandrel and stretched and cooled radially and axially. The even expansion and rec- ken is achieved by constant air supply in the space between the nozzle and the calibration mandrel. On the back of the calibration mandrel there are cutting devices on which the foamed tubular films are cut in two webs and laid flat. The procedure according to the invention, as a semi-finished or molded material, for example as a film of particularly light density, in the density range below 300 g / l, consisting of biodegradable thermoplastic materials, is produced by this procedure described by way of example. Another variant consists in that the mixture of the polymer melt and the blowing agent is injected, foamed and molded into an enclosed space (mold), as in the injection molding process or blow molding.

The foamed molding materials according to the invention have the advantage that they are semi-finished, e.g. as foamed film, have a particularly low density of less than 300 g / 1, have a uniform pore distribution with closed-pore outside and with the usual processing methods of the plastics processing industry, such as hot forming, deep-drawing or pressing, to be processed into light, compostable molded parts and packaging can.

It is also possible with the method according to the invention by injection molding and blow molding to produce lightweight and compostable molded parts or containers.

The characteristic of compostability can be determined with the standard DIN 54900, or according to the standard CEN 261, if this comes into force.

The thermoplastically deformable, weldable, foamed semi-finished products or molded parts are particularly suitable for Provision of completely biodegradable and compostable packaging materials, insulation materials, foam foils, heat, cold and sound insulation as well as for the production of fast food dishes, packaging trays for fruit, vegetables and meat, egg packaging, protective films, trays, sandwich elements, cans, bottles, Coatings for paper or cardboard. This list contains only a number of examples and is by no means exhaustive.

The invention will now be explained in more detail with the aid of a series of experiments, for example.

1 Introduction

Using a series of tests for various material mixtures, process conditions were examined to achieve good foam quality. In addition, different material mixtures were tested for their foamability. The tests were carried out on a foam extrusion line, shown in FIG. 1, with direct carbon dioxide gas injection or by injection of gaseous nitrogen, which takes place at the same position as the injection of the carbon dioxide.

With reference to FIG. 1, the biodegradable polymer, such as a polymer blend containing thermoplastic starch and optionally further polymers and additives, is entered at point 11. At position or zone 4 in the extruder, direct gassing with carbon dioxide or injection of the gaseous nitrogen takes place. Zone 8 forms a liquid-cooled cylinder extension, and zone 10 has a foam foil tool. A temperature-controlled cooling mandrel with a cutting device is designated by the reference number 12 and a draw-off for the foam sheets is given the reference number 13. 2. Recipes for carrying out the foam tests

Recipe 1: 0640GS8209 (with talc)

Raw material Ckg / h] [%]

Ecoflex 9.522 14.07

Cellulose acetate 29.508 43.60

Potato starch 4% 7.590 11.21

Talk M30 3,000 4.43

Triacetin 13.766 20.34

Glycerin 4,300 6.35

67,686

(Ecoflex = copolyester from BASF)

Recipe 2: 0640GS8210 (increased share of Ecoflex)

Raw material [kg / h] [%]

Ecoflex 15,000 22.59

Cellulose acetate 29.508 44.44

Potato starch 4% 7.590 11.43

Triacetin 10,000 15.06

Glycerin 4,300 6.48

66,398

Recipe 3: 0640GS8207 (= 0640GS8047)

Raw material [kg / h] [%]

PCL 15,000 21.41

Cellulose acetate 29.508 42.12

Potato starch 4% 7.590 10.83

Triacetin 13.766 19.65

Glycerin 4,200 5,99

70,064 (PCL = polycaprolactone)

Recipe 4: 0640GS8208 (= 0640GS8048)

Raw material [kg / h] [%]

Ecoflex S 9.522 14.77

Cellulose acetate 29.508 45.76

Potato starch 4% 7.590 11.77

Triacetin 13.766 21.35

Glycerin 4,100 6,36

64,486

3. Experiments with carbon dioxide as a blowing agent

3.1 Trials with recipe 1

In the test protocols listed below, the tests with recipe 0640GS8209 and fumigation with carbon dioxide are provided with test numbers 1 to 6. Due to the relatively high melting temperatures, the proportion of carbon dioxide had to be reduced to 0.6% in the course of the tests from 1 to 6, as breakdowns occurred at higher values. It was shown that the screw was too heavily relined for a metering setting of 30%, which is why the metering speed was increased for the last attempts.

In experiment 6, a film with a very good surface quality and a density of 540 kg / m ^{3 was} extruded with higher throughput. At the bottom, the film was slightly cracked, which was due to the tool temperature at the nozzle lip being too low. In general, the processability of recipe 1 was good and the melt was easy to pull over the mandrel. Foamability and foam structure were also good, the surface very good with good flexibility. As mentioned, gas breakthroughs occasionally occurred at lower throughput, while production ran smoothly at higher throughput.

3.2 Trials with recipe 2:

In experiments 7 to 9, the second formulation 0640GS8210 was foamed. This mixture showed a very strong build-up of pressure, which is why the melt temperature was increased to 180 ° C. To improve the surface, the mold temperature had to be raised here too. Good film surfaces were obtained for tool temperatures above 180 ° C. Higher temperatures could not be reached with the oil temperature control units used, since a relatively large amount of heat was radiated into the environment. This also explains the strong deviation of the actual and target temperatures for the tool head for experiments 8 and 9. In experiment 9, there was an approximately 2 mm thick film with a density of 427 kg / m ³ . Both the inner and the outer surface of the film was slightly scaly, on the inside the surface was also slightly torn. Both effects are due to the still too low mold temperature.

A somewhat grained outer surface ("elephant skin") came about due to the cooling conditions on the film. While the

Cooled quickly on the inside of the cooling mandrel, the outside of the film only cooled slowly due to the insulating effect of the foam and was stretched by the pulling forces. In general, for the tests with formulation 2 and CO ₂ as blowing agent, it can be stated that the melt can be drawn well over the mandrel, the foamability is very good with a very thick foam and also with a good foam structure. In contrast, the surface is rather wrinkled and worse than with the filler according to recipe 1.

3.3 Trials with recipe 3:

With recipe 3 and CO ₂ as blowing agents, tests 10 to 17 were carried out. Test 10 gave a 1.7 mm thick film with a density of 316 kg / m ³ and a smooth surface. However, there is a very coarse-cell foam structure with an average bubble size of approx. 2 mm x 0.5 mm on the surface.

In order to achieve a finer bubble structure, 0.3% by weight of a nucleating agent based on sodium bicarbonate / citric acid was added for the following experiments (Hydrocerol CF 20 E from Boehringer Ingelheim). This nucleating agent was mixed into the granules as a PE masterbatch. In experiment 11 A, with otherwise the same settings, a film slightly thicker with 2.1 mm and a density of 291 kg / m ^{3 was obtained} . Using the nucleating agent results in a slightly finer foam structure.

In the nucleated melt, more and smaller bubbles begin to grow at the tool outlet. Since the mean diffusion paths of the blowing agent from the melt into the bubbles also decrease, more gas takes part in the foaming under constant cooling conditions. In experiment 11 B, with the operating point unchanged, the outer film surface was blown with cooling air directly at the tool outlet. As a rule, this external cooling leads to lower densities, since the gas loss over the surface is reduced. This effect could not be observed here, the density of sample 11 B is rather slightly higher. Since the external cooling also makes temperature control of the last tool zone difficult, it was not used for the following tests.

In order to ensure that the nucleating agent was fully activated, cylinder zones 2-4 were raised to 200 ° C for experiments 12 to 17. Previous studies have shown that this temperature has to be exceeded for a certain time in order to ensure the complete decomposition of the nucleating agent. The increased pressures in zones 5 and 6 also indicate that there is an additional decomposition of the nucleating agent. However, some of the samples show a clear yellowing. This coloring indicates that the sensitive starch may be degraded by acid groups or thermally degraded by the high cylinder temperatures. Since there is no further reduction in density of samples 12 - 17 compared to sample 11 B, the higher cylinder temperatures for this material should be avoided.

In experiments 13 and 14, the throughput was increased in order to produce a thicker film. 7 Similar to section 2.1, however, a stable process point could no longer be set for higher speeds. The cooling capacity of the cylinder extension was not sufficient for higher throughputs to effectively cool the melt. The lower melt strength and the poorer solubility of the blowing agent led to higher densities and poorer foam qualities for temperatures above 165 ° C, since the cells partially collapsed.

Based on the settings from experiment 10, the CO ₂ content was increased to 0.7% in experiment 15 in order to produce a thicker film. At a melt temperature of 162 ° C, however, the gas could not be completely dissolved, so that breakdowns occurred. The melt temperature could also not be reduced further by reducing the cooling extension (test 16). Between the breakthroughs there was a uniform foam with a low density in the range of 250 kg / m ³ . However, the density measurement was made more difficult by the numerous gas inclusions, so that the actual density was rather higher.

In order to extrude a thicker film, the exit cross section of the tool was enlarged in experiment 17 and at the same time the speed was increased somewhat in order to compensate for the lower tool pressure. Since the proportion of blowing agent was not adjusted in this experiment, the result was a 3.2 mm thick film, but the density was again higher at 300 kg / m ³ .

Samples 16 and 17 both had a wrinkled outer surface, which, as in Experiment 9, was due to insufficient cooling on the mandrel. The effect was enhanced by the fact that the thicker foam reduced the heat transfer to the cooling mandrel.

3.4 Try with recipe 4

The tests with recipe 0640GS8208 and C0 ₂ as blowing agents are identified as tests 26 to 31 in the following test table. Since the material according to recipe 4 has a high hen pressure built up and the cylinder temperature could not be increased further, the screw had to be driven relined. Foaming the material without the addition of nucleating agent (test 27) resulted in a uniform, thick foam with a density of 214 kg / m ³ and an average bubble size of approx. 1 mm. The strong longitudinal folds in the film can be traced back to the fact that the film was not fully drawn over the cooling mandrel that was placed.

The addition of 0.3% nucleating agent in trial 28 did not significantly improve the foam structure.

A reduction in the melt temperature in experiments 30 and 31 did not result in any further density reduction. Below 155 ° C melt temperature, the streaking in the tool caused by the mandrel holder webs in the tool increased until the film on the cooling mandrel was spliced open.

4. Experiments with nitrogen as a blowing agent

4.1 Trials with recipe 3

The tests with recipe 3 0640GS8207 and nitrogen as blowing agent are identified as tests 21 to 24 in the following test protocol. At the beginning of the tests, the settings according to test 10 were adopted from the tests with carbon dioxide as a blowing agent. For these settings, a film with a density of 500 kg / m ^{3 was obtained} (test 21). The film had an excellent surface, but foamed very irregularly. Despite the low proportion of propellant, there were periodically larger gas inclusions, which dragged a long tail and broke open occasionally. Various measures to achieve the solubility of the propellant and to improve the homogenization of the melt (lowering the temperature in experiment 23, increasing the speed in experiment 26) did not bring any significant improvement in the foam quality.

4.2 Trials with recipe 4:

In the test protocol listed below, the test with formulation 0640GS8208 and nitrogen as blowing agent is identified as test 25.

As in the experiments with carbon dioxide as a blowing agent, this material showed such a high pressure build-up that the

Snail had to be driven relined. Compared to the previous material, a stiffer film with a high density of 602 kg / m ³ resulted. The surface of the film was very good. Only the inside of the film was slightly cracked, which indicates that the mold temperature is too low.

5. Conclusion

Of the recipes examined, the mixtures with 0640GS8209 (recipe 1) showed the better foaming behavior with carbon dioxide as a blowing agent. The result was a relatively fine-cell structure with good surface quality. The existing cracks and stripes can be eliminated by optimizing the trigger conditions. The density of the foam was in the range of 540 kg / m ³ and was therefore relatively high. Further attempts should show here whether the density can be further reduced by varying the proportion of blowing agent and nucleating agent.

For the foamed mixtures 0640GS8207 (recipe 3), a cylinder temperature of 180 ° C must not be exceeded, as higher temperatures lead to material build-up and discolouration in the film. This material degradation may also cause the process, at least with the screw in question, to become unstable for throughputs above 20-25 kg / h. Furthermore, the performance of the cooling extension for higher throughputs is not sufficient to effectively cool the melt. However, higher throughputs should be aimed for, particularly with regard to thicker films, since this is the only way to maintain the required pressure level of approx. 20 bar with a propellant fraction of approx. 0.5% for larger nozzle gaps.

The use of Hydrocerol CF as the nucleating agent improved both the density and the foam structure for this recipe 3, but the foam quality did not improve as significantly as expected. The effectiveness of other nucleating agent types must be tested here insofar as they can be used for these formulations.

With the formulation 0640GS8208 (formulation 4) it was possible to extrude a uniform foam with a good surface even without the use of nucleating agents. Due to the high pressure build-up of this mixture, a thick film can be foamed without lowering the pressure level in the mold too much. As with the previous recipe, the best results were achieved with a melting temperature in the range of 155 ° C to 160 ° C. Above this temperature, not enough gas can be dissolved in the melt; below this, the film is spliced at the seams in the area of the mandrel holder.

For this recipe 4, the use of Hydrocerol CF as a nucleating agent did not improve the foam quality. The foaming of recipes 0640GS8207 (recipe 3) and 0640GS8208 (recipe 4) with nitrogen resulted in somewhat more elastic foams with an excellent, shiny surface. The problem with foam extrusion with nitrogen as blowing agent is the poorer solubility of nitrogen in many materials and the extremely high diffusion rate of the small N ₂ molecule, which leads to an abrupt load on the melt during foaming. This high rate of diffusion may also be the cause of the strong breakdowns and gas inclusions in the samples.

The experiments described above with the formulations 1 to 4 carried out are of course only examples which serve to explain the present invention in more detail. Of course, the recipes mentioned and the test conditions described do not constitute any restriction, and in principle all biodegradable, compostable and thermoplastically processable polymers, gassed and foamed with a low-boiling blowing agent under pressure, come under the scope of this invention, the blowing agent being applied to the melt can be processed directly as well as pelletized in order to be foamed later in a separate processing step. , Test protocols

Claims

Claims:

1. Foamed, thermoplastically processable and thermoformable and preferably weldable semifinished product or molding or molding, consisting of at least one biodegradable and compostable material / polymer, characterized in that the semifinished product or molding or molding is obtainable by transferring the at least a biodegradable and compostable thermoplastic polymer in the extruder into a melt, by gassing the melt with a low-boiling blowing agent under pressure, the blowing agent being incorporated into the melt, the melt / blowing agent mixture being cooled to the required molding temperature and at the end of the extruder through a nozzle is extruded and granulated and / or shaped and expanded into a cellular semi-finished product, molding material or molding.

2. Semi-finished product, molded material or molded part according to claim 1, characterized in that the granules, the foamed semi-finished product, the molded material or the molded part has a much lower density than that of the biodegradable, compostable materials or the polymer or the scaffold substances.

3. Semi-finished product, molding material or molded part according to one of claims 1 or 2, characterized in that it is compostable, thermoplastic can be processed, can be welded and has a density which is less than 300 g / 1.

4. Semi-finished product, molding material or molded part according to one of claims 1 to 3, characterized in that the biodegradable polymer or a mixture thereof contains at least one of the following polymer components or mixtures thereof: a thermoplastic polysaccharide or a derivative thereof, such as cellulose or cellulose derivative, chitin or a chitin derivative, starch derivatives, destructurized starch, thermoplastic starch,

a polymer component based on natural monomers and obtainable by biochemical polymerization, i.e. based on, for example, polylactides, polyhydroxybutyric acid and copolymers with valarianic acid and / or polyesters produced by fermentation,

a polymer component which is based on monomers based on fossil raw materials and is obtainable by synthetic or chemical polymerization, i.e. e.g. on degradable polyesters and copolyesters, polyester amides, polyester urethanes, polyvinyl alcohol, ethylene vinyl alcohol.

5. Semi-finished product, molding material or molded part according to one of claims 1 to 4, characterized in that the biodegradable polymer or the mixture is obtainable by mixing in the melt of thermoplastic starch, native starch or derivatives thereof with at least one polymer component which is based on natural monomers and is obtainable by biochemical polymerization, ie based on, for example, polylactides, polyhydroxybutyric acid and copolymers with valarianic acid and / or polyester produced by fermentation and / or a polymer component which is based on monomers based on fossil raw materials and is obtainable by synthetic or chemical polymerization, ie for example on degradable polyesters and copolyesters, polyester amides, polyester urethanes, polyvinyl alcohol, ethylene vinyl alcohol and / or mixtures thereof, with a water content of <1% by weight, the thermoplastic See starch optionally initially from native starch or derivatives thereof by mixing in the melt with glycerin, glycerin acetate and / or sorbitol or another suitable low molecular weight plasticizer, with a water content of <5% by weight.

6. semi-finished product, molding material or molded part according to one of claims 1 to 5, characterized in that the biodegradable polymer or the mixture contains at least one of the following polymer components or is obtainable by mixing in the melt of cellulose, a cellulose derivative, thermoplastic starch, native starch or derivatives thereof with at least one of the following polymer components:

an aliphatic polyester,

a copolyester with aliphatic and aromatic blocks,

a polyester amide,

a cellulose ester or ether,

Polyvinyl alcohol,

a polyester urethane,

a polyethylene oxide polymer and / or mixtures thereof,

where appropriate, the mixing with the starch has to be carried out at a water content of <1% by weight and the thermoplastic starch optionally initially from native starch or derivatives thereof by mixing in the melt with glycerol, glycerol acetate and / or sorbitol or a other suitable low molecular weight plasticizers is available, with a water content of <5 wt.%.

7. Semi-finished product, molding material or molded part according to one of claims 1 to 6, characterized in that the biodegradable polymer or the mixture further contains chitin, gelatin, lignin, cellulose, derivatives of the aforementioned materials and / or mixtures thereof.

8. Semi-finished product, molding material or molded part according to one of claims 1 to 7, characterized in that the biodegradable polymer or the mixture contains at least one polymer from the following list:

Aliphatic and partially aromatic polyester

A) linear bifunctional alcohols, such as

Ethylene glycol, hexadiol or preferably butanediol and / or optionally cycloaliphatic bifunctional alcohols, such as, for example, cyclohexanedimethanol and additionally optionally small amounts of higher-functional alcohols, such as, for example, 1, 2, 3-propanetriol or neopentyl glycol, and from linear bifunctional acids, such as, for example, succinic acid or adipic acid and / - or optionally cycloaliphatic bifunctional acids, such as, for example, cyclohexanedicarboxylic acid and / - or optionally aromatic bifunctional acids, such as, for example, terephthalic acid or isophthalic acid or naphthalenedicarboxylic acid and additionally optionally small amounts of higher-functionality acids, such as trimellitic acid or B) from acid- and alcohol-functionalized building blocks, for example hydroxybutyric acid or hydroxyvaleric acid or their derivatives, for example epsiloncaprolactone,

or a mixture or a copolymer of A and B,

the aromatic acids making up no more than 50% by weight, based on all acids;

Aliphatic polyester urethanes

C) an ester fraction from linear bifunctional alcohols, such as, for example, ethylene glycol, butanediol, hexanediol, preferably butanediol, and / or optionally cycloaliphatic bifunctional alcohols, such as, for example, cyclohexanedimethanol and additionally optionally small amounts of higher-functional alcohols, such as, for example, 1, 2, 3 Propantriol or neopentyl glycol and from linear bifunctional acids, such as, for example, succinic acid or adiphic acid and / or optionally cycloaliphatic and / or aromatic bifunctional acids, such as, for example, cyelohexanedicarboxylic acid and terephthalic acid and additionally, if appropriate, small amounts of higher functional acids, such as trimellitic acid or

D) an ester fraction from acid- and alcohol-functionalized building blocks, for example hydroxybutyric acid and hydroxyvaleric acid, or their derivatives, for example epsiloncaprolactone,

or a mixture or a copolymer of C) and D), and E) from the reaction product of C) and / or D) with aliphatic and / or cycloaliphatic bifunctional and additionally optionally higher-functional isocyanates, for example tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, optionally additionally with linear and / or cycloaliphatic bifunctional alcohols and / or higher functional groups , for example ethylene glycol, butanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol,

wherein the ester fraction C) and / or D) is at least 75% by weight, based on the sum of C, D) and E);

Aliphatic-aromatic polyester carbonates

F) an ester fraction from linear bifunctional alcohols, such as, for example, ethylene glycol, butanediol, hexanediol, preferably butanediol, and / or cycloaliphatic bifunctional alcohols, such as, for example, cyclohexanedimethanol and additionally optionally small amounts of higher-functional alcohols, such as, for example, 1,2,3- Propanetriol or neopentyl glycol and from linear bifunctional acids, such as, for example, succinic acid or adipic acid and / or optionally cycloaliphatic bifunctional acids, such as, for example, cyelohexanedicarboxylic acid and additionally, if appropriate, small amounts of higher-functional acids such as trimellitic acid or G) from an ester fraction from acid- and alcohol-functionalized building blocks, for example hydroxybutyric acid or hydroxyvaleric acid or their derivatives, for example epsiloncaprolactone

or a mixture or a copolymer of F) and G) and

H) a carbonate component which is produced from aromatic bifunctional phenols, preferably bisphenol A and carbonate donors, for example phosgene,

wherein the ester fraction F) and / or G) is at least 70% by weight, based on the sum of F), G) and H);

Aliphatic polyester amides

I) an ester fraction from linear and / or cycloaliphatic bifunctional alcohols, such as, for example, ethylene glycol, hexanediol, butanediol, preferably butanediol, cyclohexanedimethanol, and additionally optionally small amounts of higher-functional alcohols, e.g. 1,2,3-propanetriol or neopentyl glycol, as well as from linear and / or cycloaliphatic bifunctional acids, e.g. Succinic acid, adipic acid, cyelohexanedicarboxylic acid, preferably adipic acid and additionally optionally small amounts of higher functional acids, e.g. Trimellitic acid, or

K) from an ester fraction from acid- and alcohol-functionalized building blocks, for example hydroxybutyric acid, or hydroxyvaleric acid, or their derivatives, for example epsiloncaprolactone,

or a mixture or a copolymer of I) and K), and

L) an amide portion of linear and / or cycloaliphatic bifunctional and additionally optionally small amounts of higher functional amines, e.g. Tetramethylene diamine, hexamethylene diamine, isophorone diamine, as well as from linear and / or cycloaliphatic bifunctional and additionally optionally small amounts of higher functional acids, e.g. Succinic acid or adipic acid, or

M) from an amide portion of acid- and amine-functionalized building blocks, preferably Σ-laurolactam and particularly preferably Σ-caprolactam,

or a mixture of L) and M) as an amide component, wherein

the ester content I) and / or K) is at least 30% by weight, based on the sum of I), K), L) and M).

9. Semi-finished product, molding material or molded part according to one of claims 1 to 8, characterized in that the biodegradable polymer or the mixture contains at least starch, for example in the form of destructurized or thermoplastic starch and as a further biodegradable polymer and / or optionally as Plasticizer or swelling agent of starch a polymer from the following list:

Aliphatic and partially aromatic polyester A) linear bifunctional alcohols, such as, for example, ethylene glycol, hexadiol or, preferably, butanediol and / or optionally cycloaliphatic bifunctional alcohols, such as, for example, cyclohexanedimethanol and additionally optionally small amounts of higher-functional alcohols, such as, for example, 1, 2, 3-propanetriol or neopentyl glycol, and also from linear bifunctional alcohols Acids, such as, for example, succinic acid or adipic acid and / - or optionally cycloaliphatic bifunctional acids, such as, for example, cyelohexanedicarboxylic acid and / - or optionally aromatic bifunctional acids, such as, for example, terephthalic acid or isophthalic acid or naphthalenedicarboxylic acid and additionally optionally small amounts of higher-functional acids, such as trimellic acid or for example trimell

B) from acid- and alcohol-functionalized building blocks, for example hydroxybutyric acid or hydroxyvaleric acid or their derivatives, for example epsiloncaprolactone,

or a mixture or a copolymer of A and B,

the aromatic acids making up no more than 50% by weight, based on all acids;

Aliphatic polyester urethanes

C) an ester fraction from linear bifunctional alcohols, such as, for example, ethylene glycol, butanediol, hexanediol, preferably butanediol, and / or optionally cycloaliphatic table bifunctional alcohols, such as cyclohexanedimethanol and additionally optionally small amounts of higher functional alcohols, such as 1, 2, 3-propanetriol or neopentyl glycol, and from linear bifunctional acids, such as succinic acid or adiphic acid and / or optionally cycloaliphatic and / or aromatic bifunctional acids , such as, for example, cyelohexanedicarboxylic acid and terephthalic acid and additionally, if appropriate, small amounts of higher-functionality acids, such as trimellitic acid or

or a mixture or a copolymer of C) and D), and

E) from the reaction product of C) and / or D) with aliphatic and / or cycloaliphatic bifunctional and additionally optionally higher-functional isocyanates, e.g. Tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, optionally additionally with linear and / or cycloaliphatic bifunctional and / or higher-functional alcohols, e.g. Ethylene glycol,

Butanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol,

wherein the ester content C) and / or D) is at least 75% by weight, based on the sum of C, D) and E); Aliphatic-aromatic polyester carbonates

F) an ester fraction from linear bifunctional alcohols, such as, for example, ethylene glycol, butanediol, hexanediol, preferably butanediol, and / or cycloaliphatic bifunctional alcohols, such as, for example, cyclohexanedimethanol and additionally, if appropriate, small amounts of higher-functional alcohols, such as, for example, 1,2,3-pro- pantriol or neopentyl glycol and from linear bifunctional acids, such as, for example, succinic acid or

Adipic acid and / or optionally cycloaliphatic bifunctional acids, such as, for example, cyelohexanedicarboxylic acid and additionally optionally small amounts of higher-functional acids, such as trimellitic acid or

G) from an ester fraction from acid- and alcohol-functionalized building blocks, for example hydroxybutyric acid or hydroxyvaleric acid or their derivatives, for example epsiloncaprolactone

or a mixture or a copolymer of F) and G) and

Aliphatic polyester amides I) an ester fraction from linear and / or cycloaliphatic bifunctional alcohols, such as, for example, ethylene glycol, hexanediol, butanediol, preferably butanediol, cyclohexanedimethanol, and, if appropriate, small amounts of higher-functional alcohols, for example 1,2,3-propanetriol or neopentyl glycol, and from linear and / or cycloaliphatic bifunctional acids, for example succinic acid, adipic acid, cyelohexanedicarboxylic acid, preferably adipic acid and, if appropriate, small amounts of higher-functionality acids, for example trimellitic acid, or

or a mixture or a copolymer of I) and K), and

M) from an amide portion of acid- and amine-functionalized building blocks, preferably Σ-laurolactam and particularly preferably Σ-caprolactam, or a mixture of L) and M) as an amide component, wherein

10. Semi-finished product, molding material or molded part according to one of claims 1 to 9, characterized in that the biodegradable polymer or the mixture optionally contains thermoplastic or destructurized starch and as a plasticizer or

Swelling agent or, as a further degradable polymer, a polyester copolymer obtainable by polycondensation of at least one diol from the 1, 2-ethanediol, 1,3-propanediol, 1,4-butanediol and / or 1,6-hexanediol series on the other hand with at least one aromatic di-carboxylic acid, such as terephthalic acid and optionally at least one aliphatic di-carboxylic acid, such as adipic acid and / or sebacic acid.

11. Semi-finished product, molding material or molded part according to one of claims 1 to 10, characterized in that the biodegradable polymer or the mixture contains at least one of the following polymers: polylactic acid, polyhydroxybutyric acid, polyhydroxybenzoic acid, polyhydroxybutyric acid-hydroxyvaleric acid copolymer or polycaprolactone.

12. Semi-finished product, molded material or molded part according to one of claims 1 to 11, characterized in that the biodegradable

Polymer or the mixture optionally contains starch, such as thermoplastic starch, and as a plasticizer or swelling agent and / or as a further, biodegradable polymer, at least one polymer from the list below: - Oligomeric polyester amides with a molecular weight from 300, preferably from 1000, and polymeric polyester amides from 1000 mol / wt. , preferably over 10,000, obtainable by synthesis from the following monomers:

Dialcohols such as ethylene glycol, 1, 4-butanediol, 1, 3-propanediol, 1, 6-hexanediol, diethylene glycol and others. and / or dicarboxylic acid such as oxalic acid, succinic acid, adipic acid and others. also in the form of their respective esters (methyl, ethyl, etc.) and / or hydroxycarboxylic acids and lactones such as caprolactone and others. and / or amino alcohols such as ethanolamine, propanolamine etc. and / or cyclic lactams such as -caprolactam or laurolactam etc. and / or -amino carboxylic acids such as aminocaproic acid etc. and / or mixtures (1: 1 salts) of dicarboxylic acids such as adipic acid, succinic acid etc. and Diamines such as hexamethylene diamine, diaminobutane, etc.

13. Semi-finished product, molding material or molded part according to one of claims 1 to 12, characterized in that the biodegradable polymer or the mixture optionally contains starch, such as thermoplastic starch, and a cellulose acetate, propionate and / or butyrate or a mixture thereof and / or cellulose esters in the form of a mixed ester, in the preparation of which an acid mixture containing at least two of the following carboxylic acids is used as the esterification component:

- acetic acid

- propanoic acid - butyric acid

- valeric acid.

14. Semi-finished product, molding material or molding according to one of claims 1 to 13, characterized in that the biodegradable polymer or the mixture optionally contains starch, such as thermoplastic starch, and at least one further component, such as an additive, additive or filler, such as a plasticizer, a stabilizer, an anti-flame agent, another biodegradable biopolymer, such as cellulose ester, cellulose, polyhydroxybutyric acid, a hydrophobic protein, polyvinyl alcohol, gelatin, zein, polysaccharide, polylactide, polyvinyl acetate, polyacrylate, a sugar alcohol, shellac Ca-, a fatty acid derivative, vegetable fibers, lecithin or chitosan.

15. A process for producing a foam, molded foam part, a foamed, thermoplastically processable, heat-formable and weldable semi-finished product, molded material or molded part made of a compostable material / polymer, characterized in that the biodegradable and compostable, thermoplastic polymer in the extruder in a melt is transferred, the melt is gassed with a low-boiling blowing agent directly under pressure and the blowing agent is incorporated into the melt, the melt-blowing agent mixture is cooled to the required shaping temperature and extruded through a nozzle at the end of the extruder and into a granulate or a cellular semi-finished product or molded material or molded part and expanded.

16. The method according to claim 15, characterized in that as a biodegradable, compostable, thermoplastic Polymer in particular at least one polymer is selected from one of claims 4 to 14.

17. The method according to any one of claims 15 or 16, characterized in that nitrogen, carbon dioxide and / or an aliphatic carbon, such as iso-pentane or n-pentane, is used as the gaseous blowing agent.

18. The method according to any one of claims 15 to 17, characterized in that a mixture of citric acid and sodium bicarbonate and / or azobicarbonamide is used as a blowing agent or as a cell former.

19. The method according to any one of claims 15 to 17, character- ized in that the gas by exact dosing pumps

Pressure is metered into the melt, the fumigated melt is cooled, the cooled, fumigated melt is extruded into granules or a foam sheet.

20. The method according to any one of claims 15 to 19, characterized in that the granules containing the blowing agent are further processed by extrusion or injection molding or by means of hot air or hot steam.

21. The method according to any one of claims 15 to 18, characterized in that the cooled, fumigated melt is processed into an injection molded product.

22. The method according to any one of claims 15 to 21, characterized in that further cell formers are used if necessary.

23. Use of the semifinished product, molding material or molded part according to one of claims 1 to 13 for the production of completely biodegradable and compostable packaging materials, insulating materials, foam films, heat, cold and sound insulation, fast food dishes, packaging trays for fruit, vegetables and meat , Egg packaging, protective films, trays, sandwich elements, cans, bottles and / or coatings for paper and cardboard.