WO1999023118A1

WO1999023118A1 - The reaction of a polyhydroxy polymer or a derivative thereof with a lactone

Info

Publication number: WO1999023118A1
Application number: PCT/IB1998/001734
Authority: WO
Inventors: Jürgen LOERCKS; Claudio Pellegrini; Harald Schmidt; Ivan Tomka
Original assignee: Bio-Tec Biologische Naturverpackungen Gmbh & Co.Kg
Priority date: 1997-11-05
Filing date: 1998-10-30
Publication date: 1999-05-14
Also published as: CN1278268A; EP1028981A1; AU9554698A; JP2001521947A

Abstract

The invention relates to the reaction of a polyhydroxy polymer or a derivative thereof with at least one lactone, lactam or one suited carboxylic acid in order to produce a preferably biodegradable polymer resulting in a homogenous melting, preferably by means of extrusion reaction.

Description

Reaction of a polyhydroxy polymer or a derivative thereof with a lactone

The present invention relates to a process for reacting at least one polyhydroxy polymer and / or a polyhydroxy polymer derivative with at least one lactone, a lactam or a suitable carboxylic acid and a thermoplastic biodegradable composition based on polyhydroxy polymer derivatives, comprising a reaction product of at least one a polyhydroxy polymer and / or a polyhydroxy polymer derivative and at least one lactone, a lactam or a suitable carboxylic acid.

Polymers and polymer mixtures based on polyhydroxy polymers, such as in particular polyhydroxyacetal, polyvinyl alcohol, polyvinyl alcohol-polyvinyl acetate copolymer, polyvinyl alcohol acetal or a polyhydroxy ether, or based on a polyhydroxy polymer derivative by reaction with alcohols, fatty acids, esters, such as, in particular, lactones , in solutions or suspensions with useful properties, are known.

For example, U.S. Patents 3,922,239, 5,011,637, DE 501889, and EP-A 0 244 206 et al. Cellulose esters and / or reaction or mixed products from cellulose derivatives with i.a. Lactones, triacetin etc. and their uses are described.

US Pat. No. 3,922,239 describes thermoplastic compositions consisting of mixtures of cellulose esters and / or ethers which are mixed with cyclic esters. For example, ε-caprolactone is used as the cyclic ester, the mechanical properties of the polymer mixtures produced being inadequate. GB 2 152 944 and the two Japanese patent applications JP 59-86621 and JP 60-188402 describe the reaction of cellulose acetate with cyclic esters such as caprolactone, the reaction mixture in xylene being used as a solution or Plasticizer is dissolved. In the two Japanese patent applications, plasticizers such as diethyl phthalate or dimethyl phthalate are additionally added to the reaction mixture.

EP 0 635 649 proposes adding a plasticizer to the cellulose acetate first. This is intended to reduce the amount of lactone required, which is associated with a reduction in costs. These additional plasticizers are alcohol derivatives. Depending on the mixing ratio of this alcohol derivative and the lactone, the properties of the plasticized cellulose acetate can be adjusted.

In practice, however, it has now been shown that the plasticization of cellulose derivatives or generally polyhydroxy polymers, such as in particular polyhydroxyacetal, polyvinyl alcohol, polyvinyl alcohol-polyvinyl acetate copolymers, polyvinyl alcohol acetal or polyhydroxy ether or derivatives thereof, by adding plasticizers, as well as that Use of solvents and the like is undesirable because these plasticizers, solvents and the like remain in the polymer to be produced. For example, onomeric portions or traces of solvent which have not been removed are inadmissible in food foils, since these low molecular weight fractions can slowly diffuse out of the foil, which jeopardizes their suitability for foodstuffs. It is therefore an object of the present invention to propose or produce polymers or reaction products at least from polyhydroxy polymers or polyhydroxy polymer derivatives, such as in particular from polysaccharides or their derivatives and lactones or, if appropriate, further reaction partners which do not have the disadvantages mentioned at the outset .

According to the invention, a method for producing such a polymer based on polyhydroxy polymer or polyhydroxy polymer derivative according to the wording according to claim 1 or 2 is proposed, and a corresponding polymer based on polyhydroxy polymer derivatives according to the wording according to claim 21.

The polyhydroxy polymer according to the present invention is a polyhydroxyacetal such as polysaccharide, polyvinyl alcohol, such as a polyvinyl alcohol-polyvinyl acetate copolymer, polyvinyl alcohol-polyethylene-

Copolymer to polyvinyl alcohol acetal or a polyhydroxy ether such as polyglycerol, polyerithritol, polypentaerithritol, polysorbitol, polymannitol, polyethylene glycol, polypropylene glycol, poly 1, 3-propanediol, etc.

It is now proposed according to the invention that the reaction between the polyhydroxy polymer or the polyhydroxy polymer derivative and the lactone and / or optionally the further reaction partner, such as a lactam or a selected carboxylic acid, such as, for example, formic acid, takes place continuously in the homogeneous phase, for example in an extruder or kneader in which, on the one hand, owing to the thorough mixing, the diffusion paths between the reactants are very short, in contrast to, for example, batch or pot reactions. In addition, due to this very short diffusion relatively short residence times or reaction times are chosen, with which the chain length of the polymer remains practically unchanged, ie there is no degradation of the polyhydroxy polymer derivative.

Furthermore, it is advantageous to use an extruder or kneader when mixing and reacting the polyhydroxy polymers with a lactone, a lactam or a selected carboxylic acid, since this enables the reaction partners to be mixed as homogeneously as possible. Polyhydroxy polymers are rather hydrophilic, while, for example, lactones are rather hydrophobic, which means that the mixture is then two-phase, unless high shear conditions of an extruder or kneader are used. The high shear conditions result from the geometry of the bore and the screw or screws in the extruder or kneader as well as from the high pressure that is built up along the screw in the extruder.

The advantage of the present invention is in particular that the quasi-solvent or the plasticizer in the homogeneous phase are simultaneously the reactants to the polyhydroxy polymer or the derivative thereof and are largely, preferably completely, incorporated into the polyhydroxy polymer during the reaction. As a rule, further workup of the polyhydroxy polymer derivative produced according to the invention is therefore unnecessary. Any water arising as a result of the esterification reaction or any residual water within the polyhydroxy polymer can be removed in the extruder along the screw or, if appropriate, before the material is ejected by venting, in particular in order to shift the balance of the esterification reaction to a higher degree of esterification. The reaction product can be processed thermoplastically without the need to add other plasticizers. Other benefits include the following:

No water-soluble or oil-soluble by-products are released in the extraction test for food packaging. In this regard, reference is made to common test methods used for food suitability.

The mechanical properties, for example of foils, films, fibers, produced according to the described extrusion processes show useful or good mechanical properties, such as:

Simple pull test:

- Module over 300 MPa

- Stress at break (compressive strength) over 20 Mpa

- elongation at break over 10%

As is known, there are a large number of polyhydroxy polymers, such as polysaccharides or polyvinyl alcohols, such as, in particular, inexpensive, partially hydrolyzed polyvinyl acetates which are water-soluble. Polyvinyl alcohol-polyethylene copolymers, for example, are too hygroscopic and lose water barrier properties if used as film materials. This can be counteracted by reacting such partially hydrolyzed polyvinyl alcohol or the polyvinyl alcohol-polyethylene copolymer mentioned with caprolactone. The same naturally also applies to polyvinyl alcohol acetals. Polyglycerin is inexpensive but too hy wholesale copy. This can be counteracted by reaction with caprolactone.

The following materials, in particular, have proven to be suitable polysaccharides or polysaccharide derivatives, representative of polyhydroxy polymer derivatives:

Gums: Arabicum = Acacia gum, tragacanth, carragenan, furcelaran, ghatti, guar, locust bean, psyllium, quince, tamarind-karaya gum;

Plant extracts: Agar = extract Gelidium s. , Alginates = block copolymer from beta-D-mannuronic acid and alfa-L-guluronic acid, arabinogalactan, pectin;

Fermentation products: dextran, xanthan, curdlan, scleroglucan;

Bacterial extracts: yeast glucan, pullulan, Zanflo-10, Zanflo-21: Reg.Mark Kelco Division, Merck & Co., Inc., PS-7: Azotobacter indicus, Bacterium alginate: Azotobacter vinelandii,

as well as other starches like Com, Tapioca, Potato, Wheat, Rice etc. ;

Celluloses and cellulose derivatives such as carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, as well as further methyl ether of pectin, hydroxypropyl alginates;

modified starches;

Shellfish extracts, chitin and chitosan.

The above list is by no means exhaustive, and other derivatives of the above polysaccharides are also suitable to be implemented according to the present invention with lactones, lactams and / or suitable carboxylic acids. The following derivatives are particularly suitable:

Formates, acetates, butyrates, propionates or generally esters, ethers, alkyl ethers such as, for example, ethyl cellulose, methyl cellulose etc. and carboxymethyl derivatives such as hydroxyalkyl ethers, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose. It is essential that the derivative or derivatives are soluble in lactones.

As is known, there are a large number of polysaccharides which are already in large quantities or are used. Examples include the following, which are used industrially in large quantities:

Corn starch, potato starch, corn sugar, agar, Arabic gum, guar, pectin, carboxymethyl cellulose and xanthan, to name just a few examples.

Polysaccharide acetate (diacetate), formate, butyrate and propionate, such as cellulose sulfate (diacetate), formate and butyrate, have proven to be particularly suitable polysaccharide derivatives, the degree of substitution being at least about 1.5, however should not be higher than approx. 2.6. Caprolactone, dilactide and diglicidyl lactone (2-glycolic acid) and corresponding lactams, such as, for example, caprolactam or carboxylic acids, such as, in particular, formic acid, are particularly suitable as lactones or other reaction partners.

The polysaccharide, again representative of a polyhydroxy polymer, or the derivative thereof, for example 1, 3 Polyglucan, cellulose formate, chitin formate or starch formate is preferably first premixed with the lactone, such as caprolactone, at room temperature and then introduced into an extruder or kneader, where the two reaction partners are melted. When the melt is driven through the extruder, the reaction takes place between the polysaccharide derivative and the lactone, it being possible for any monomers present in the reaction mixture, such as, in particular, unreacted lactone as well as low-molecular reaction products formed and excess water to be removed by degassing. This is due to the preferred embodiment mentioned above, that the polymer or reaction product finally produced preferably contains as little or no monomers as possible which can diffuse out of the polymer.

In particular, alkoxylates of alkali and alkaline earth metals, as well as rare earths, have proven to be catalysts for carrying out the proposed reaction. However, alkoxylates of Group IV metals are also suitable, such as, in particular, titanium alkoxylates, which titanium compounds are known from the prior art, for example GB 2 152 944 and EP 636 649.

Primary, secondary and tertiary butyrate and isopropylate compounds of the elements mentioned have proven to be particularly suitable. Examples include yttrium oxide isopropylate, aluminum isopropylate, tetrabutyl orthotitanate and potassium tertiary butoxide. Triethanolamine titanate (TEAT) has also proven to be suitable. The catalysts previously proposed according to the invention are generally suitable in principle for the reaction of polyhydroxy polymers or derivatives thereof with lactones. In principle, when carrying out the reaction and producing the polymers proposed according to the invention, it should preferably be observed if the products are used in contact with food, pharmaceuticals or cosmetic products:

1. that the reaction product preferably contains essentially only highly polymeric substances, i.e. no small molecules that can diffuse out. This is due to the requirement, for example, for food suitability, as well as the requirement for good mechanical properties;

2. that the reaction is carried out in an extruder, which makes it possible to at least largely be able to remove all low molecular weight substances. When using the catalyst, care must be taken to ensure that the alcohols released can be removed by degassing.

3. The chain length should preferably not change. In other words, care must be taken when carrying out the reaction that the polyhydroxy polymer derivative is not degraded. Again, this can be achieved by choosing the extrusion reaction, for example, since, as mentioned above, there are very short diffusion paths between the reaction partners in the extruder. This is in contrast to batch reactors or so-called "pot reactors". In the case of a batch reaction, the reaction time is usually too long, so there is a risk of the basic structure of the polyhydroxy polymer or the polyhydroxy polymer derivative being degraded. The preferably biodegradable polymers proposed according to the invention can also be obtained by mixing the polyhydroxy polymer or polyhydroxy polymer derivative (s) with at least one other biodegradable polymer or polyhydroxy polymer or derivatives thereof before or during reaction with the lactones, lactams or suitable carboxylic acids (for example) starch, a starch derivative such as starch acetate, chitin and / or cellulose.

Furthermore, it is also possible to use the preferably biodegradable polymer according to the invention, based on a polyhydroxy polymer derivative, as a blend component with further polymers, such as, for example, thermoplastically processable starch or polylactides or other aliphatic polyesters. The thermoplastically processable starch is a starch which is produced from native starch using a suitable plasticizer or swelling agent, and when reacting in the melt of the native starch with the plasticizer or swelling agent, the moisture is released is reduced to less than 5% by weight, preferably to less than 1% by weight. Suitable plasticizers or swelling agents are, in particular, glycerol, sorbitol or preferably, in turn, the lactones or lactams mentioned at the outset, such as, in particular, ε-caprolactone, ε-caprolactam and polymers produced therefrom, such as, for example, polycaprolactone.

The invention will now be explained in more detail with reference to the accompanying examples and the acquisition of experimental data.

Experiments 1 to 3: Material:

Cellulose diacetate from Courtaulds Acetate, type FM5N, ref. 33-18-2, FSE 346 in a high vacuum (0.2 mbar) while 3d dried at 70 ° C. The DS is 2.45 (1H-NMR at 80 ° C in d ₆ -DMSO).

Reaction management:

30 g (146 mmol) of the cellulose diacetate are premixed at room temperature (RT) with 15 g (132 mmol) of caprolactone (CA) and at 160 ° C. and 30 rpm. placed in a chamber kneader. After a melting time of 10 minutes, 500 mg (1.47 mmol)

Ti (O-nButyl) _{4 added} over 1 min. Samples are taken from the reaction mixture after a certain time (Table 1). To determine the bound CL content of the cellulose, the samples are washed with toluene: 1 g sample is suspended in 10 g toluene and stirred at 40 - 50 ° C for 60 min., The cooled suspension is centrifuged and decanted . This procedure is repeated three more times with the fixed residue. According to 1H NMR, the supernatant contains only polycaprolactone (PCL).

Experiments 4 to 6:

In contrast to experiments 1 to 3, where the ratio between CA and CL is 2: 1, experiments 4 to 6 select the ratio 1: 1. Again, the determined sales and free CL values are summarized in Table 1.

Experiments 7 to 9:

In contrast to experiments 1 to 6, in experiments 7 to 9 AL (0-iPro) ₃ , ie aluminum isopropylate, was used as the catalyst used. As a first consequence it can be observed that, in contrast to the use of titanium alkoxylate, where discoloration of the melt occurred, no yellow discoloration of the samples occurs when using the aluminum isopropylate. In addition, there is better catalytic activity, which in turn can be read from the results summarized in Table 1.

Table 1 Experiments in the chamber kneader

a) Experiments 1-3: CA (30 g), CL (15 g), Cat. (0.5 g) Experiments 4 - 6: CA (25 g), CL (25 g), Cat. (0.5 g) Experiments 5 - 9: CA (30 g), CL (20 g), Cat. (0.5 g)

⁾ Parts by weight of CL found in the sample by 1H-NMR

c) Turnover = CL reacts / (CL reacts + CL unreacted) Try 10 to 16:

Since it is not possible to increase the temperature in the chamber kneader above the specified 160 ° C., further tests 10 to 16 are carried out in a single-screw extruder. For this purpose, a premix of CA, CL and catalyst is produced in a kneader at 160 ° C and then extruded at a higher temperature in a single-screw extruder. The results and the temperature set in the extruder are summarized in Table 2.

Table 2:

Mechanical properties:

The samples produced in the single-shaft extruder were measured directly and the values of the mechanical properties are summarized in Table 3. Table 3

The good correlation between unreacted caprolactone and the mechanical properties can be clearly seen from the attached FIGS. 1 and 2. The quality of the mechanical properties decreases with increasing free caprolactone in the samples.

Determination of the softening point:

The softening point (EP) of materials, such as polymers in particular, is an important criterion for defining the range of use under practical and environmental conditions. In this regard, the softening points of the common polymers (LDPE, HDPE) of a biodegradable polymer, ie of polycaprolactone, were examined and compared with the softening points of the cellulose acetate derivatives from Table 2, experiments 15 and 16. The corresponding measured values are shown in Table 4 below: Table 4: Heat resistance of PCL, LDPE, HDPE and CA derivatives:

For a polymer to be suitable as a packaging material, it must have good heat resistance. The minimum requirement is that the heat resistance is> 100 ° C, i.e. according to the value for LDPE. The plasticized cellulose acetate produced for example in accordance with EP 636 649 have a heat resistance which is below 100 ° C., which is due to the use of the plasticizer. Finally, it can be seen from Table 4 that, for example, pure PCL is not a suitable material due to its poor heat resistance.

Further tests in synchronous, self-cleaning twin-screw extruders have shown that the reaction time can be reduced further. Comparative experiments have shown, for example, that a reaction time in a chamber kneader of 60 minutes can initially be reduced to 20 minutes if the same reaction is carried out in a single-screw extruder. When using a synchronous, self-cleaning twin-screw extruder, the dwell time or reaction time can be longer Approx. 7 minutes can be reduced, which meets the above-mentioned requirement for the molecular weight to be as constant as possible, in that the reaction time is very short. This enables a further optimization of the cellulose acetate derivatives or copolymers produced, for example, in experiments 10 to 16.

Experiments 17 to 24:

Use of a further biodegradable polymer together with cellulose acetate:

Reaction procedure: A premix of cellulose acetate (CA) with a degree of substitution (DS) of 1.8 resp. 2.45, starch acetate

(SA) with a degree of substitution (DS) of 1.4 and / or strength

(Amylose) and / or cellulose and caprolactone (CL) are mixed in different ratios, as listed in Table 5, in the chamber kneader at 160 ° C and 30 rpm. melted for 5 minutes. 300 mg of aluminum isopropylate are then mixed in and kneaded for a further 10 minutes. The premixes thus obtained are then at 220 ° C and at 100 U / min. treated in a twin-screw reflux extruder for 15 minutes.

Tab. 5: Premixes of experiments 17 to 24; the numbers are all in grams

No. CA SA Amylose Cellulose CL

DS = 1, 8

17 13.3 6.7 10

18 10 10 10

19 6.7 13.3 10

20 10 - 10 10

21 10 10 10

DS = 2.45

22 13.3 6.7 10

23 10 10 10

24 6.7 13.3 10

Mechanical properties: Various mechanical properties were measured from the reaction products obtained in experiments 17 to 24, which are summarized in Table 6 below.

Tab. 6: The sales and mechanical properties

No. Turnover Elastic Elongation Elongation Tension modulus at max. in case of break in case of break

burden

Mpa in% in% Mpa

17 76.3 867 9.8 25.2 33.1

18 76.2 825 9.1 18.5 30.8

19 80.7 864 8.1 10.6 28.6

20 92.5 941 6.4 6.7 28

21 82.6 1400 5.1 5.1 29.5

22 72.0 806 8.6 20.6 32.3

23 72.6 775 7 7.1 29.1

24 71.7 834 6.6 6.6 33.1 Experiments 25-32:

Material: cellulose, chitin and starch

The starting compounds, i.e. Derivatives of the three materials listed above, such as cellulose formate, chitin formate and starch formate, were prepared according to a slightly modified regulation by Heinze et al. (Liebert T., Klemm D., Heinze T., J. Mat. Sei. Pure Appl. Chem., A33 (5), 1996, 613-626).

Cellulose formate: 1.0 g of dry cellulose was mixed with 30 ml of formic acid at room temperature. 2.7 ml of phosphorus oxychloride were added dropwise. After 6 h, the viscous solution was poured onto 200 ml of diethyl ether. The precipitate was filtered and washed well three times with 100 ml of acetone each time. Excess water and formic acid were drawn off under reduced pressure in the extruder.

Chitin formate: analogous to the production of cellulose formate.

Starch formate: 1.0 g of dry potato starch was dissolved in 30 ml of formic acid at room temperature. Thereafter, 10 ml of acetic anhydride were added and stirring was continued for two days. The solution was poured onto 200 ml of diethyl ether. The precipitate was washed three times with 100 ml of cold acetone.

Reaction management:

1. Preparation of the premixes from cellulose formate, chitin formate and starch formate with caprolactone and catalyst:

Experiment 25: 30 g of cellulose formate were premixed at room temperature with 22 g of caprolactone (CL) and 500 mg of triethanolamine titanate (TEAT) and in a chamber kneader at 160 ° C for 15 min. melted.

Trial 26

Analogous to experiment 25, but with chitin formate.

Experiment 27:

Analogous to experiment 25, but with starch formate.

In the further experiments, the amount of CL and the amount of catalyst were varied.

2. Implementation of the premix prepared under 1. in a twin-screw extruder:

Experiment 28:

4-5 g of the premix was at 200 ° C for 15 min. extruded.

Trial 29:

Analogous to experiment 28, but at 220 ° C.

3. Implementation of cellulose formate, chitin formate and starch formate with CL and catalyst in a co-rotating twin-screw extruder (ZSK-30, W + P)

Trial 30:

Temperature profile of the ZSK-30:

Cellulose formate (dosing rate 2 kg / h) was dosed as a powder in the water-cooled feeder. In zone 2, a mixture of CL and TEAT (2 parts: 0.035 parts) was injected at a rate of 1.5 kg / h. A vacuum of 300 mbar was applied in zone 6. The emerging strand was air-cooled and granulated.

Trial 31:

Temperature profile of the ZSK-30:

The premix, which was prepared in experiment 30, was extruded again at a metering rate of 2 kg / h. The time in the extruder is approx. 5 min.

Trial 32:

In further experiments, either chitin formate or starch formate was used. The caprolactone and catalyst content were changed in further experiments. The reaction temperature was changed in further experiments. The number of passes was increased in further tests.

Measurement of mechanical properties of films, produced from the above-mentioned polymers according to the invention and using known extrusion processes:

- Simple tensile test: module over 300 Mpa

- Stress at break (compressive strength) over 20 Mpa - Elongation at break over 10%.

Further examples for the assessment of various catalysts:

Reaction procedure: A premix of 20 g of cellulose acetate with a degree of substitution of 2.45 and 20 g of caprolactone are mixed in a chamber kneader at 160 ° C. and 30 rpm. melted for 15 minutes. Then 50 mg of catalyst are added to 5 g portions of this premix, followed by further treatment at 220 ° C. and 100 rpm. in a twin-screw reflux extruder for 5 to 30 minutes.

The following catalysts were examined:

1. Aluminum isopropylate = AI

2. Potassium tert. Butylate = K

3. Titanium tetra butylate = Ti

4. Neodynium (11 /) chloride = Nd

Table 7 summarizes both sales and selected mechanical properties.

Tab. 7

Example of process parameters for the reaction extrusion of cellulose diacetate with lactones

A practical example under operating conditions during reaction extrusion in a twin-screw extruder from cellulose derivatives with lactones to plasticizer and solvent-free, biodegradable materials is described below. The twin-screw extruders used for the reaction extrusion are synchronous twin-screw extruders with tightly intermeshing screw profiles and have individually temperature-controlled kneading zones (for example the Werner & Pfleiderer ZSK type).

For the reaction extrusion, twin-screw extruders with eight chambers or zones are used, which can optionally be expanded to 10 to 12 zones and have the following structure:

Extruder design: co-rotating twin screw extruder

Screw length = process length = 32 - 40 L / D

Screw diameter D = 45 mm

Screw speed = 230 rpm.

Throughput = 50 - 65 kg / h nozzle, diameter = 3 mm

Nozzle, number = 4 pieces

The following operating conditions exist in the individual chambers:

Feed zone 1 Compression with degassing of premixed raw materials up to zone 3, gradually melt the mixture

Cellulose derivatives, lactones, catalysts

Zone 4 withdrawal of volatile by-products

Degassing by means of a vacuum system, Production of the anhydrous melt

Zones 5 - 7 reaction chambers, transition homogenization of the melt, compression, drag and pressure flow, reaction zone pressure build-up, discharge zone 8 evaporation of further volatile

By-products and extrusion (or

Injection molding) Outside the extrusion system: cooling and conditioning of the starch, if necessary absorption of 0.1 - 0.4% water as a plasticizer in a water bath, strand granulation and bagging.

In Table 8 below, for example, extrusion conditions for the production of thermoplastic, plasticizer-free cellulose derivatives by reaction with lactones are listed.

Ta. 8th

The above-mentioned example extrusion conditions can of course also be used in the reaction extrusion of cellulose derivatives or of other polyhydroxy polymers together with other biodegradable polymers, such as cellulose, starch or starch acetate with lactones, lactams or suitable carboxylic acids.

The invention is of course not limited to the examples described above, since these examples only serve to explain the present invention in more detail.

It is fundamentally essential to the invention that the reaction of polyhydroxy polymers or derivatives thereof and, if appropriate, a further biodegradable polymer with lactones, lactams or suitable carboxylic acids is carried out continuously in an extruder or that a so-called extrusion reaction is preferably chosen for the reaction. The catalysts already known from the prior art, such as, in particular, the known titanium compounds, can be used here, as can the alkoxylates of alkali metals, alkaline earth metals and earth metals, such as, in particular, rare earths, mentioned for the first time in the present invention. The proposed, preferably biodegradable polymer blends based on polyhydroxy polymer derivatives and possibly. Further biodegradable polymers and lactones, lactams or suitable carboxylic acids generally form clear-sighted to ocher-colored films and foils. They are free of plasticizers and in accordance with the regulations for packaging food in accordance with LMBG (Food and Consumer Goods Act). As a rule, they are completely biodegradable and compostable according to DIN 54900.

The processing properties can be varied by varying the melt flow index from (MFI g / 10 ') 5 - 12 for the production of blown films, flat films, (MFI g / 10') 2 - 9 for the production of plates, injection molded products and blow molding of bottles, (MFI g / 10 ') 20 - 30 can be changed and adapted for the production of fibers (at 190 ° C and 2.15 kg load).

Applications:

Due to the special combinations of properties as compostable food packaging, the following applications are preferred: Single and multilayer films and composite films made from the polyhydroxy polymer derivative according to the invention as packaging for food, but also for non-food products, fast food trays, cups, straws, cutlery, cups and Films for dairy products, transparent covers, paper coatings and laminates, disposable items.

The following applications are proposed in the technical field: bags and sacks for collecting compostable waste, garden articles such as plant pots, candle covers, fibers, nonwovens, diaper film, films for letter windows, agricultural films, pyrotechnic products, toys. In the plastics-producing industry, the new polymer based on polysaccharide derivative is suitable as a blend component for the production of biodegradable materials, as a phase mediator in blends made of hydrophilic and hydrophobic thermoplastics, especially for blends made of destructurized or thermoplastic starch with synthetic degradable polymers.

Claims

Claims:

1. A process for reacting at least one polyhydroxy polymer or polyhydroxy polymer derivative with at least one lactone, characterized in that the reaction takes place in a largely homogeneous melt.

2. Process for reacting at least one polyhydroxy polymer or polyhydroxy polymer derivative with at least one lactam or a carboxylic acid, characterized in that the reaction takes place in a largely homogeneous melt.

3. The method, in particular according to one of claims 1 or 2, characterized in that the lactone or the lactones, the lactam or the lactams and / or the carboxylic acids with the hydroxypolymer or the derivative thereof forms a molecularly disperse mixture.

4. The method, in particular according to one of claims 1 to 3, characterized in that the reaction takes place by means of an extrusion reaction.

5. The method, in particular according to one of claims 1 to 4, characterized in that the at least one polyhydroxy polymer or derivative thereof is selected from the list below:

Polysaccharide, polyols, polyhydroxyacetal, polyvinyl alcohol, polyvinyl alcohol-polyvinyl acetate copolymer, polyvinyl alcohol-polyethylene copolymer, polyvinyl alcohol acetal, polyhydroxy ether, a derivative of the aforementioned polymers or copolymers and / or mixtures thereof.

6. The method, in particular according to claim 5, characterized in that at least one of the following materials is selected as the polysaccharide or derivative:

Gums: Arabicum = Acacia gum, tragacanth, carragenan, furcelaran, ghatti, guar, locust bean, psyllium, quince, tamarind;

Plant extracts: Agar = extract Gelidium sp. , Alginate = block copolymer of beta-D-mannuonic acid and alfa-L-guluronic acid, arabinogalactan, pectin;

Fermentation products: dextran, xanthan, curdlan, scleroglucan;

Bacterial extracts: yeast glucan, pullulan, Zanflo-10, Zanflo-21: Reg.Mark Kelco Division, Merck & Co., Inc., PS-7: Azotobacter indicus, acterium alginate: Azotobacter vinelandii,

as well as other starches such as corn, tapioca, potatoes, wheat, rice etc. ;

Cellulose and cellulose derivatives such as carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and also methyl ether of pectin, hydroxypropyl alginates;

modified starches;

Shellfish extracts, chitin and chitosan.

7. The method, in particular according to one of claims 5 or 6, characterized in that at least one acetate, diacetate, formate, butyrate or propionate of a polysaccharide is reacted with caprolactone, a di-lactide or diglicidyl lactone (2-glycolic acid) by means of an extrusion reaction becomes.

8. The method, in particular according to one of claims 1 to 7, characterized in that the at least one polyhydroxy polymer or derivative thereof is a polyhydroxy ether, such as polyglycerol, polyerithritol, polypentaerithritol, polysorbitol, polymannitol, etc.

9. The method, in particular according to one of claims 1 to 8, characterized in that the at least one polyhydroxy polymer or derivative thereof is a polyvinyl alcohol, such as in particular a partially hydrolyzed polyvinyl alcohol or a derivative thereof.

10. The method, in particular according to one of claims 1 to 9, characterized in that the polyhydroxy polymer or the derivative thereof with the lactone if necessary. is premixed into an extruder or kneader and melted and then the melt is intimately mixed along an extruder or kneader and, if necessary, at least partially degassed in order to add unreacted, low molecular weight lactone from the reaction mixture before the melt is discharged from the extruder or kneader enter.

11. The method, in particular according to one of claims 1 to 10, characterized in that the polyhydroxy polymer or the derivative is reacted with the at least one lactone together with at least one further biodegradable polymer.

12. The method, in particular according to one of claims 6 to 11, characterized in that a cellulose derivative, optionally a further biodegradable polymer and the lactone are premixed and introduced into an extruder and melted, whereupon the melt is mixed with the catalyst and finally, the melt is intimately mixed in the extruder in a temperature range of approximately 160 to 230 ° C., lactone which has not reacted before the melt is discharged and alcohols formed by reacting the catalyst are at least partially removed by degassing.

13. The method, in particular according to one of claims 6 to 12, characterized in that cellulose acetate or diacetate, formate or butyrate with a degree of substitution between 1.4 and about 2.6 optionally together with the further biodegradable Ren polymer is mixed in a ratio of 1: 1 to 3: 1 with caprolactone and in a temperature range of about 160 ° C to about 230 ° C in an extruder, such as in particular a co-rotating, self-cleaning twin-screw extruder for about 5 to 20 minutes. is mixed in the melt, and that the melt is degassed before being discharged to at least partially discharge low-molecular substances, such as unreacted caprolactone and reaction products formed when the catalyst is reacted.

14. The method, in particular according to one of claims 6 to 13, characterized in that the cellulose derivative together with

Starch, starch acetate and / or cellulose is reacted with caprolactone, the ratio of cellulose derivative to the further biodegradable polymer being from approximately 3: 1 to approximately 1: 3.

15. The method, in particular according to one of claims 1 to 14, characterized in that an alkoxylate of the catalyst

Alkali metals, alkaline earth metals, earth metals or rare earths is used.

16. The method, in particular according to one of claims 1 to 15, characterized in that the at least one polyhydroxypo lymer or derivative thereof with caprolactone, a di-lactide or diglicidyllactone (2-glycolic acid) is reacted by means of an extrusion reaction.

17. The method, in particular according to one of claims 6 to 16, characterized in that at least cellulose acetate,

diacetate, formate or butyrate with caprolactone, a di-lactide or diglicidyl lactone (2-glycolic acid) is reacted by means of an extrusion reaction.

18. The method, in particular according to one of claims 1 to 17, characterized in that a tertiary butylate, secondary butylate, primary butylate or an isopropylate is used as catalyst.

19. The method, in particular according to one of claims 1 to 18, characterized in that triethanolamine titanate (TEAT) is used as a catalyst.

20. The method, in particular according to one of claims 1 to 19, characterized in that an yttrium alkoxylate, an aluminum alkoxylate, a potassium alkoxylate and / or a titanium alkoxylate is used, in particular yttrium oxide isopropylate, aluminum Isopropylate, tetrabutyl orthotitanate and / or potassium tertiary butra is used as a catalyst.

21. Thermoplastic, preferably biodegradable composition based on at least one polyhydroxy polymer derivative, containing a reaction product of at least one polyhydroxy polymer or a derivative thereof and at least one lactone, which can be obtained by reacting the reaction mixture in a homogeneous melt, as preferably in an extruder, which reaction product is preferably at least largely free of low molecular weight substances.

22. Thermoplastic, preferably biodegradable composition based on at least one polyhydroxy polymer derivative, comprising a reaction product of at least one polyhydroxy polymer or a derivative thereof and at least one lactam and / or a carboxylic acid, which can be obtained by reacting the reaction mixture in a homogeneous melt, such as preferably in an extruder, which reaction product is preferably at least largely free of low molecular weight substances.

23. Thermoplastic composition, in particular according to claim 21 or 22, obtainable by reacting a polyacetal, such as polysaccharide, a polyvinyl alcohol, polyvinyl alcohol-polyvinyl acetate copolymer, polyvinyl alcohol-polyethylene-

Copolymers, polyvinyl alcohol acetals or a polyhydroxy ether such as polyglycerol, polyerithritol, polypentaerithritol, polysorbitol, polymannitol etc. and / or mixtures thereof with caprolactone in a ratio of 1: 1 to 3: 1 using a catalyst comprising an alkoxylate of an element of the

Alkali metals, alkaline earth metals, earth metals, rare earths and / or titanium.

24. Thermoplastic composition, in particular according to one of claims 21 to 23, obtainable by reacting a polysaccharide acetate, diacetate, formate, butyrate and / or a propionate with a degree of substitution of approximately 1.4 to approximately 2, 6, optionally together with another biodegradable polymer, such as starch, starch acetate, chitin, cellulose and / or a cellulose derivative with caprolactone or caprolactam Ratio 1: 1 to 3: 1 using a catalyst comprising an alkoxylate of an element of the alkali metals, alkaline earth metals, earth metals, rare earths and / or titanium.

25. Thermoplastic composition, in particular according to one of claims 21 to 23, obtainable by reacting cellulose acetate, diacetate, formate and / or butyrate with a degree of substitution of about 1.4 to about 2.6, optionally together with a further biodegradable polymer such as starch, starch and / or cellulose with caprolactone or caprolactam in a ratio of 1: 1 to 3: 1 using a catalyst, comprising an alkoxylate of an element of the alkali metals, alkaline earth metals, earth metals, the rare ones Earth and / or titanium.

26. Use of the thermoplastic, preferably biodegradable compositions based on at least one polyhydroxy polymer derivative produced by one of the processes according to claims 1 to 20 for the production of blown films, flat films, sheets, injection molded products, bottles and fibers.

27. Use of the thermoplastic, preferably biodegradable compositions based on at least one polyhydroxy polymer derivative produced by one of the processes according to claims 1 to 20 as a blend component for the production of biodegradable materials and as a phase mediator in polymer blends of hydrophilic and hydrophobic thermoplastics, in particular for blends Made from destructurized or thermoplastic starch with synthetic degradable polymers.

28. Single-layer or multilayer film and composite film containing at least one layer, made from a thermoplastic see, preferably biodegradable composition according to any one of claims 21 to 25.

CHANGED REQUIREMENTS

[Received at the International Bureau on April 16, 1999 (April 16, 1999); original claims 1-28 by; new claims 1-27 replaced; all other claims unchanged (7 pages)] _! , ". _V experience for reacting at least one polyhydroxy polymer or polyhydroxy polymer derivative with at least one lactone, a lactam and / or a carboxylic acid, characterized in that the reaction by means of extrusion reaction by using high shear conditions in the extruder or kneader in a largely homogeneous melt takes place, any water arising as a result of the esterification reaction or any residual water, any monomers contained in the reaction mixture, low molecular weight reaction products and, in particular, alcohols liberated when a catalyst is used are removed by degassing.

2. The method according to claim 1, characterized in that the lactone or the lactones, the lactam or the lactams and / or the carboxylic acids with the hydroxypolymer or the derivative thereof forms a molecularly disperse mixture.

3. The method according to any one of claims 1 or 2, characterized gekennzeichne that the at least one polyhydroxylated polymer or derivative thereof is selected from the following list _t,:

4. The method according to claim 3, characterized in that at least one of the following materials is selected as the polysaccharide or derivative: Gums: Arabicum = Acacia gum, tragacanth, carragenan, furcelaran, ghatti, guar, locust bean, psyllium, quince, tamarind;

Plant extracts: Agar = extract Gelidium sp., Alginate = block copolymer from beta-D-mannuoronic acid and alfa-L-guluronic acid, arabinogalactan, pectin;

Fermentation products: dextran, xanthan, curdlan, scleroglucan;

as well as other starches like Com, Tapioca, Potato, Wheat, Rice etc. ;

Cellulose derivatives such as carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and also methyl ether of pectin, hydroxypropyl alginates;

modified starches;

Shellfish extracts, chitin and chitosan.

5. The method according to any one of claims 3 or 4, characterized in that at least one acetate, diacetate, formate, butyrate or propionate of a polysaccharide is reacted with caprolactone, a di-lactide or diglicidyl lactone (2-glycolic acid) by means of an extrusion reaction.

6. The method according to any one of claims 1 to 5, characterized in that the at least one polyhydroxy polymer or derivative thereof is a polyhydroxy ether, such as Polyglycerin, polyerithritol, polypentaerithritol, polysorbitol, polymannitol, etc.

7. The method according to any one of claims 1 to 6, characterized in that the at least one polyhydroxy polymer or derivative thereof is a polyvinyl alcohol, such as in particular a partially hydrolyzed polyvinyl alcohol or a derivative thereof.

8. The method according to any one of claims 1 to 7, characterized in that the polyhydroxy polymer or the derivative thereof, optionally premixed with the lactone, is introduced into an extruder or kneader and melted and then the melt is intimately mixed along an extruder or kneader and, if necessary is at least partially degassed in order to remove unreacted, low molecular weight lactone from the reaction mixture before the melt is discharged from the extruder or kneader.

9. The method according to any one of claims 1 to 8, characterized in that the polyhydroxy polymer or the derivative is reacted with the at least one lactone together with at least one further biodegradable polymer.

10. The method according to any one of claims 4 to 9, characterized in that a cellulose derivative, optionally a further biodegradable polymer and the lactone are premixed and introduced into an extruder and melted, whereupon the melt is mixed with the catalyst and then the melt in Extruder is intimately mixed in a temperature range from approx. 160 to 230 ° C., lactone which has not reacted before the melt is discharged and alcohols formed by reacting the catalyst are at least partially removed by degassing.

11. The method according to any one of claims 4 to 10, characterized in that cellulose acetate or diacetate,

-formate or -butyrate with a degree of substitution between 1.4 and approx. 2.6, if appropriate together with the further biodegradable polymer, is mixed with caprolactone in a ratio of 1: 1 to 3: 1 and in a temperature range of approx. 160 ° C to approx. 230 ° C in an extruder, such as in particular a co-rotating, self-cleaning twin-screw extruder, is mixed in the melt for approx. 5 to 20 minutes, and that the melt is degassed before it is discharged to at least partially discharge low-molecular substances, such as unreacted caprolactone and reaction products formed when the catalyst is reacted.

12. The method according to any one of claims 4 to 11, characterized in that the cellulose derivative together with starch,

Starch acetate and / or cellulose is reacted with caprolactone, the ratio of cellulose derivative to the further biodegradable polymer being from about 3: 1 to about 1: 3.

13. The method according to any one of claims 1 to 12, characterized in that an alkoxylate of alkali metals, alkaline earth metals, earth metals or rare earths is used as the catalyst.

14. The method according to any one of claims 1 to 13, characterized in that the at least one polyhydroxy polymer or derivative thereof is reacted with caprolactone, a di-lactide or diglicidyl lactone (2-glycolic acid) by means of an extrusion reaction.

15. The method according to any one of claims 4 to 14, characterized in that at least cellulose acetate, diacetate, formate or butyrate with caprolactone, a di-lactide or diglicidyl lactone (2-glycolic acid) is reacted by means of an extrusion reaction.

16. The method according to any one of claims 1 to 15, characterized in that a tertiary butylate, secondary butylate, primary butylate or an isopropylate is used as catalyst.

17. The method according to any one of claims 1 to 16, characterized in that triethanolamine titanate (TEAT) is used as a catalyst.

18. The method according to any one of claims 1 to 17, characterized in that an yttrium alkoxylate, an aluminum alkoxylate, a potassium alkoxylate and / or a titanium alkoxylate is used, in particular yttrium oxide isopropoxide, aluminum isopropoxide, tetrabutyl orthotitanate and / or potassium tertiary butra is used as a catalyst.

19. Thermoplastic, preferably biodegradable composition based on at least one polyhydroxy polymer derivative, containing a reaction product of at least one polyhydroxy polymer or a derivative thereof and at least one lactone, which can be obtained by reacting the reaction mixture in a homogeneous melt, such as preferably in a Extruder, which reaction product is at least largely free of low molecular weight substances.

20. Thermoplastic, preferably biodegradable composition based on at least one polyhydroxy polymer derivative, containing a reaction product of at least one polyhydroxy polymer or a derivative thereof and at least one lactam and / or a carboxylic acid, which is available by reacting the reaction mixture in a homogeneous melt, such as preferably in an extruder, which reaction product is at least largely free of low molecular weight substances.

21. Thermoplastic composition according to claim 19 or 20, obtainable by reacting a polyacetal such as polysaccharide, a polyvinyl alcohol, polyvinyl alcohol-polyvinyl acetate copolymer, polyvinyl alcohol-polyethylene copolymer, polyvinyl alcohol acetal or a polyhydroxy ether such as polyglycerol, polyerithritol, polypentaerithritol , Polymannitol, etc. and / or mixtures thereof with caprolactone in a ratio of 1: 1 to 3: 1 using a catalyst comprising an alkoxylate of an element of the alkali metals, alkaline earth metals, earth metals, rare earths and / or titanium .

22. Thermoplastic composition according to one of claims 19 to 21, obtainable by reacting a polysaccharide acetate, diacetate, formate, butyrate and / or a - propionate with a degree of substitution from about 1.4 to about 2.6, optionally together with another biodegradable polymer such as starch, starch acetate, chitin, cellulose and / or a cellulose derivative with caprolactone or caprolactam in a ratio of 1: 1 to 3: 1 using a catalyst comprising an alkoxylate of an element of the alkali metals, alkaline earth - limetals, earth metals, rare earths and / or titanium.

23. Thermoplastic composition according to one of claims 19 to 21, obtainable by reacting cellulose acetate, diacetate, formate and / or butyrate with a degree of substitution of about 1.4 to about 2.6, optionally together with another Biodegradable polymer such as starch, starch acetate and / or cellulose with caprolactone or caprolactam in a ratio of 1: 1 to 3: 1 using a catalyst comprising an alkoxylate of an element of the alkali metals, alkaline earth metals, earth metals, rare earths and / or from Titan.

24. Use of the thermoplastic, preferably biodegradable compositions based on at least one polyhydroxy polymer derivative produced by one of the processes according to claims 1 to 18 for the production of blown films, flat films, sheets, injection molded products, bottles and fibers.

25. Use of the thermoplastic, preferably biodegradable compositions based on at least one polyhydroxy polymer derivative produced by one of the processes according to claims 1 to 18 as a blend component for the production of biodegradable materials and as a phase mediator in polymer blends of hydrophilic and hydrophobic thermoplastics, in particular for blends Made from destructurized or thermoplastic starch with synthetic degradable polymers.

26. Single or multilayer film and composite film containing at least one layer made from a thermoplastic, preferably biodegradable composition according to one of claims 19 to 23.

27. Use of the thermoplastic, biodegradable compositions produced by one of the processes according to claims 1 to 18 for the production of compostable food packaging. DECLARATION REFERRED TO IN ARTICLE 19

Based on the references cited in the international search report, the claims of the present international patent application have been revised and adapted in such a way that they are both new and inventive against the background of the cited documents.

Reactions between polyhydroxy polymers and lactones or carboxylic acids are certainly described in the prior art, but in these reactions some of the reaction parameters which are essential for the present invention are not or only insufficiently weighted. These are e.g. working in the homogeneous melt, the use of a solvent being dispensed with or wherein the reactant to the polyhydroxy polymer also serves as a solvent or plasticizer, the reaction is carried out in an extruder or kneader under suitable, high shear conditions in order to ensure the production of a homogeneous melt, the reaction product produced being largely free of monomers, in particular of Water to be particularly suitable for use in the food sector.

The following comment applies:

In WO98 / 06755 native starch is reacted with, inter alia, esters, ester amides, fatty acids etc. for the production of starch polymer mixtures, the starch first being mixed with a suitable plasticizer, such as water, formic acid, caprolactone and the reaction product of the starch with the Ester, ester amide, etc. when the degree of substitution of the basic molar units of strength of 0.8 is reached to remove unbound plasticizer and water is degassed. According to Japan Abstracts JP 06 287279, the ring opening process in the graft copolymerization of a lactide and a cellulose ester or ether is described.

EP 0 704 470 describes the preparation of a lactone-modified polyvinyl alcohol, the proposed polyvinyl alcohol derivatives still having a high water absorption or swelling.

WO96 / 20220 describes the production of thermoplastic starch by reacting native starch with i.a. Lactic acid and polycaprolactone are described.

DE 44 28 211 finally describes the reaction of cellulose ester with caprolactone. It is suggested that the acid component of the ester that may be released when the cellulose ester is reacted is removed from the melt by degassing; the basic removal of any monomeric components, such as unreacted monomers, excess water, etc., is not an issue in this publication.