WO1998004412A1

WO1998004412A1 - Compostable backing foil

Info

Publication number: WO1998004412A1
Application number: PCT/EP1997/003745
Authority: WO
Inventors: Thomas Gernot; Dirk Schultze; Michael Stiem; Gunter Weber
Original assignee: Wolff Walsrode Ag
Priority date: 1996-07-26
Filing date: 1997-07-14
Publication date: 1998-02-05
Also published as: CN1226203A; CA2262000A1; AU3694797A; JP2000516545A; DE19630231A1; BR9710571A; KR20000029557A; IL128074A0; EP0914250A1; AU718448B2

Abstract

A compostable backing foil is composed of at least two layers and has a low tendency to curling and on one side gloss values lower than 10, measured according to DIN 67 530 at a 20° angle. The outer layer of the foil, which has the lower gloss values, contains 1-80 % by weight of a uniformly distributed filler with a mean particle size < 22 νm. The individual layers of the polymer-resin layered structure contain as matrix materials polymers from the group composed of (I) aliphatic and partially aromatic polyesters; (II) aliphatic polyester urethanes; (III) aliphatic-aromatic polyester carbonates; (IV) aliphatic polyester amides.

Description

Compostable carrier web

The invention relates to biodegradable, in particular compostable, films which are produced by extrusion from the melt.

The invention relates to low-curl, multilayer, at least two-layer films with an asymmetrical layer structure, which can be produced by coextrusion and are obtained directly as matt films without further treatment steps in the manufacturing process. The films consist of compostable polymers or copolymers and contain large amounts of mineral filler in one of the outer layers. Due to the unexpected similar volume contraction of the filled and unfilled layers of the at least two-layer film during the manufacturing process, the films according to the invention have an extremely low tendency to curl. They can also contain proportions of processing aids, color pigments and stabilizers. Due to their silky matt surface characteristics, these foils are suitable for low-gloss covering of surfaces. For example, they can be used as carrier films for wound plasters, adhesive plasters or plaster strips.

The films according to the invention are suitable for a large number of applications, the main emphasis here being on the use as carrier films for wound plasters. Wound plasters generally consist of a carrier material coated with a pressure sensitive adhesive, a wound covering which is smaller in area than the carrier material and a release material which protects the pressure sensitive adhesive and wound covering during storage. Films for such applications have to meet a multitude of requirements, in addition to the technical and aesthetic requirements.

Films for medical plasters must be dimensionally stable, can be chemically or physically pretreated in order to be printed and / or coated.

The aesthetic requirements include primarily a silky matt

Surface that ensures a skin-like appearance. Matt surfaces are generally judged by the gloss, minimum gloss values are aimed for. Gloss values <10 have generally proven themselves for plasters, measured according to DIN 67 530, at an angle of 20 °. The haptics of the plaster films must also be appealing, in particular a soft grip.

When a plaster cut is used, the load caused by tensile forces remains practically low, since the pressure sensitive adhesive has a particularly low adhesive bond to a commonly used release material, such as siliconized paper or rigid foils. Plaster cuts differ here from roller plasters, where higher peel forces can occur because there is no separating layer and the adhesive layer lies on the outside of the plaster.

Likewise, films for roller plasters are not very soft

Materials. In the longitudinal tensile load, as z. B. occurs when removing it as adhesive tape from the roll, a small longitudinal stretch is desirable and generally set.

In this respect, not only the high tensile strength and / or tensile strength are required to characterize a suitable film material for use as a carrier film for plaster blanks. Elongation at break values are decisive, but also represent the initial elongation values under tensile load as important evaluation criteria.

In the past, matt-calendered polyvinyl chloride (PVC) films were used as carrier films. The public discussion about the health effects of the monomer vinyl chloride and the so-called external plasticizers, with phthalate plasticizers in particular becoming the focus of criticism, intensified the pressure to substitute plasticized PVC.

The requirements for films for medical plasters are described, for example, in German utility model applications GM 90 12 161.9 and GM 93 06 768.2 (both Beiersdorf). The classification of plasters is regulated by the respective pharmacopoeia, in Germany this is for example DAB 10 (1991).

It is known that certain polymeric materials can undergo biodegradation. Mainly materials to be mentioned here are those that are obtained from naturally occurring polymers directly or after modification, for example polyhydroxyalkanoates such as polyhydroxybutyrate, plastic Celluloses, cellulose esters, plastic starches, chitosan and pullulan. A targeted variation of the polymer composition or the structures, as is desirable on the part of the polymer application, is difficult and often only possible to a very limited extent due to the natural synthesis process.

However, many of the synthetic polymers are not attacked by microorganisms, or only very slowly. Mainly synthetic polymers that contain heteroatoms in the main chain are considered to be potentially biodegradable. The polyesters represent an important class within these materials. Synthetic raw materials which only contain aliphatic monomers have a relatively good biodegradability, but can only be used to a very limited extent on account of their material properties, cf. Witt et al. in Macrom Chem Phys, 195 (1994) S 793 - 802. Aromatic polyesters, on the other hand, show significantly deteriorated biodegradability with good material properties

Various biodegradable polymers have been known recently (see DE 44 32 161). These have the property that they can be processed easily thermoplastically and, on the other hand, are biodegradable, ie their entire polymer chain is split by microorganisms (bacteria and fungi) via enzymes and completely degraded to carbon dioxide, water and biomass A corresponding test in a natural environment under the influence of microorganisms, as u. a. prevails in a compost, among other things. in the

Given DIN 54 900

The object of the present invention is to provide thermoplastically processable and completely biodegradable plastic films with fillers in such a way that no synthetic materials remain in the compost and have a good mechanical profile of properties, in particular strength and impact resistance

It was necessary to provide a matted film in such a way that it can be obtained from the film production process without further mechanical treatment steps. In order to ensure easy further processing into carrier films for plaster cuts, the film required should be low-curl

Visibility, the film according to the invention should be free of halogen compounds and aromatic plasticizers with a comparatively low molecular weight. It should have at least one side with a good adhesion, so that it is self-adhesive can be easily coated with a pressure sensitive adhesive on common transfer laminating machines. In addition, the film should be adjustable so that it can adapt flexibly to skin movements in the wound area. Largely isotropic properties in the film level are advantageous for the universal use of the film.

The object is achieved by incorporating mineral fillers into at least one layer of a multilayer film which can be produced from thermoplastic, biodegradable molding materials.

The present invention thus relates to rigid, yet tough, biodegradable plastic films, characterized in that mineral

Fillers, in particular of natural origin, which are thermoplastic incorporated into completely biodegradable polymers, are used as the base material of at least one outer layer of the film. Accordingly, the object of the present invention is to be seen in the fact that a biodegradable and compostable film with improved mechanical and optical

Providing properties The terms "biodegradable and compostable polymers or foils" are understood in the sense of this invention to mean goods which are tested for biodegradability in accordance with the test according to DIN 54 900 from the 1996 draft

The film according to the invention is preferably obtained by processing from the melt, the different layers showing only slight differences in their volume contraction when cooling, so that a low-curl structure is obtained. The film according to the invention can contain the additives customary in plastics processing.

The invention also relates to a film which has a biaxial orientation and consists of one or more all biodegradable and compostable polymers and possibly contains additional additives to improve processability. The biaxial orientation takes place in the case of amorphous thermoplastics in temperature ranges above the glass transition temperature and in the case of partially crystalline thermoplastics below the crystallite melting temperature. The invention also relates to the use of the matted compostable films as a carrier web of adhesive tapes which are coated on one side with the pressure-sensitive adhesives known from the prior art. In particular, this relates to adhesive tapes that are processed into wound or active substance plasters.

The layer structure according to the invention is made up of at least one layer (1) made of a compostable polymer and / or a compostable copolymer and / or mixtures thereof, optionally with the addition of suitable colors and stabilizing additives in effective amounts and at least one second matted layer (2) educated

The layer (2) is characterized in that it is a matrix, i. h with a predominant proportion, has compostable polymers and receives the matting by adding a filler. The same polymer as layer (1) is preferably used as the matrix material for layer (2). Possibly. can be arranged between layers (1) and (2) further layers (3), which in turn are preferably formed from a compostable matrix resin

Suitable polymers are:

Aliphatic and partially aromatic polyester

A) linear bifunctional alcohols, for example ethylene glycol, hexanediol or preferably butanediol, and / or optionally cycloaliphatic bifunctional alcohols, for example cyclohexanedimethanol, and additionally, if appropriate, small amounts of higher-functionality alcohols, for example 1,2,3-propanetriol or neopentyl glycol, and also from linear bifunctionals Acids, for example succinic acid or adipic acid, and / or optionally cycloaliphatic bifunctional acids, for example cyclohexanedicarboxylic acid, and / or optionally aromatic bifunctional acids, for example terephthalic acid or isophthalic acid or naphthalenediarboxylic acid, and additionally optionally small amounts of higher-functionality acids, for example trimellitic acid, or B) from acid- and alcohol-functionalized building blocks, for example hydroxybutyric acid or hydroxyvaleric acid, or their derivatives, for example ε-caprolactone,

or a mixture or a copolymer of A and B

the aromatic acids not more than 50% by weight based on all

Identify acids.

The acids can also be used in the form of derivatives, for example acid chlorides or esters

Aliphatic polyester urethanes

C) an ester fraction from linear bifunctional alcohols, for example

Ethylene glycol, butanediol, hexanediol, preferably butanediol, and / or optionally cycloaliphatic bifunctional alcohols, for example cyclohexanedimethanol, and additionally optionally small amounts of higher-functionality alcohols, for example 1,2,3-propanetriol or neopentylglycol, and from linear bifunctional acids, for example

Succinic acid or adipic acid, and / or optionally cycloaliphatic and / or aromatic bifunctional acids, for example cyclohexanedicarboxylic acid and terephthalic acid, and additionally optionally small amounts of highly functional acids, for example 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 ε-caprolactone,

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 isocyanates and additionally optionally high-functionality isocyanates, for example tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and optionally additionally with linear and / or cycloaliphatic bifunctional isocyanates and / or higher-functional alcohols, for example ethylene glycol, butanediol, hexanediol, neopentylglucol, 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, for example ethylene glycol, butanediol, hexanediol, preferably butanediol, and / or cycloaliphatic bifunctional alcohols, for example cyclohexanedimethanol, and additionally, if appropriate, small amounts of higher-functional alcohols, for example 1,2,3-propanπol or neopentyl glycol, as well as from linear bifunctional acids, for example succinic acid or adipic acid, and / or possibly cycloaliphatic bifunctional acids, for example cyclohexanedicarboxylic acid, and, if appropriate, small amounts of higher-functionality acids, for example trimellitic acid, or

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

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, for example ethylene glycol, hexanediol or butanediol, preferably butanediol or cyclohexanedimethanol, and additionally if necessary, small amounts of higher-functional alcohols, for example 1,2,3-propanetriol or neopentylgycol, and of linear and / or cycloaliphatic bifunctional acids, for example succinic acid, adipic acid, cyclohexanedicarboxylic acid, preferably adipic acid and additional, if appropriate, small amounts of higher-functional acids, for example 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 ε-caprolactone,

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

L) an amide component from linear and / or cycloaliphatic bifunctional and additionally optionally small amounts of higher-functional amines, for example tetramethylene diamine, hexamethylene diamine, isophorone diamine, and from linear and / or cycloaliphatic bifunctional acids and, if appropriate, small amounts of higher-functionality acids, for example succinic acid or Adipic acid, or

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

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

wherein the ester fraction I) and / or K) at least 30% by weight based on the

Sum of I), K), L) and M).

The biodegradable and compostable raw materials according to the invention can be equipped with processing aids and additives, such as, for example, nucleating agents (for example 1,5-naphthalene disodium sulfonate), stabilizers or lubricants.

The biodegradable copolyesters, polyester urethanes, polyester carbonates and polyester amides have a molecular weight of at least 10,000 g / mol and have a statistical distribution of the starting materials (monomers) in the polymer. Among the biodegradable polymers mentioned are preferably polyester urethanes and polyester carbonates and particularly preferably polyester amides.

The invention furthermore relates to the use of a certain class of materials of the biodegradable and compostable polymers for the production of the film, this class of material being polyester amide. The film according to the invention can be produced from a polyester amide or a mixture of different polyester amides.

Suitable matting agents for layer (1) of the film according to the invention are minerals which are used in powder form, as is customary for incorporation into non-biodegradable thermoplastic materials.

The mineral fillers include, for example and preferably, gypsum, wollastonite, and particularly preferably chalk and kaolin. Natural and synthetic silicas are also to be regarded as suitable. Layered silicates are particularly suitable.

The thermoplastic molding compositions for layer (1) contain 1% by weight to 80% by weight, preferably 10% by weight to 60% by weight, particularly preferably 20% by weight to 40% by weight of minerals, preferably of natural origin

In a particularly preferred embodiment, the layered silicate portion of the matted layer of the film according to the invention should advantageously be at least 10

% By weight so that a clear matting is achieved and, on the other hand, does not exceed 25% by weight. Surprisingly, there is no noticeable impairment of the mechanical strength.

The invention also relates to a method for producing the reinforced thermoplastic molding compositions according to the invention, characterized in that the fillers z. B are intimately mixed with the biodegradable polymer in a kneader or preferably extruder.

It is generally of primary economic benefit if the frosted

Layer has a small proportion of the total layer thickness of the one-sided matt film. Thickness combinations in are therefore of particular interest where the proportion of the layer matted with layered silicate is 15 - 40% of the total layer thickness.

The matting layered silicate is preferably added in the form of an additive masterbatch, which in a particularly preferred embodiment has a proportion by weight of layered silicate between 30 and 80% by weight. A smaller proportion has economic disadvantages, while a higher proportion of layered silicate in the masterbatch has a poor distribution brings with it, which is shown, for example, in unwanted silicate agglomerates. This causes a more uneven roughness and thus a more unpleasant feel

Compostable ones have been developed for the production of such additive masterbatches

Polymers or compostable copolymers with a comparatively high melt flow medium between 8 and 24 g / 10 min, measured in accordance with DIN 53 735 at 190 ° C and a test load of 2.16 kg, have been preserved In order to improve the masterbatch homogeneity, other plasticizing aids can be used if necessary such as waxes may be included to prevent thermal

Damage to the polymer component of the masterbatch, the latter are usually equipped with stabilizers

In a preferred embodiment, individual or all layers of the multilayer film according to the invention can be modified by further addition of processing aids, fillers, paints and stabilizers. Colors enable the production of plasters for special areas of application

In one of these selected embodiments, at least one of the layers of colored pigments contains a beige-colored film, which is popular when the wound and wound covering are not to be openly visible. Colorful colors and printing applications are often used in children's plasters. Other additives such as

Silicates and waxes modify the application properties, in particular the sliding behavior. Stabilizers make it possible to preserve the films according to the invention over a longer period of time or to avoid damage during processing. The common additives for plastics are from Gachter and Muller in the handbook of plastic additives, Hanser Publishing company,

Munich 1983 The invention also relates to processes for producing the film according to the invention

These processes are characterized in that the biodegradable and compostable materials are first broken down by the action of heat and shear, the melt streams are superimposed and discharged in a tool, and cooled until solidification. This can be done by the known processes of Flat or blown film extrusion happen

These processes are described, for example, by Michaeli in extrusion tools for plastics and rubber, Carl Hanser Verlag, Munich 1991

Further information can be found in the handbook of plastic extrusion technology, published by Hensen, Knappe and Potente, Carl Hanser Verlag, Munich 1989

Immediately afterwards, the film can be wound up, but also further treatment by tempering and / or orientation and / or surface finishing on one or both sides

With regard to their later use, the films according to the invention can be modified in their surface properties by means of a surface finishing process. Conventional corona, plasma or fluorine but also flame treatments are particularly suitable for this purpose. Such processes were described, for example, by Dorn and Wahono in Maschinenmarkt 96 (1990 ) 34-39 or Milker and Moller in Kunststoffe 82 (1992) 978-981 detailed. A preferred method is the corona treatment

The corona treatment is expediently carried out in such a way that the film is passed between two conductor elements serving as electrodes, with such a high voltage between the electrodes - usually an alternating voltage of approximately 10 kV with a frequency? of 10 kHz - is present that spray or corona discharges can take place. These discharges ionize the air along the film surface, so that there are reactions on the film surface which are more polar compared to the polymer matrix

Groups emerge. The treatment intensities required for the pretreatment of the films according to the invention are in the usual range, action intensities are preferred which result in surface tensions of 38 to 50 mN / m

The films according to the invention can be pretreated on one or both sides. Such treatments serve to improve the surfaces with regard to their adhesion properties to printing and / or coating materials. In the case of plasters, the usual printing applications are, for example, colorful animals or objects, which are preferably printed on the matt side of children's plasters with pressure sensitive adhesives is a common procedure for plasters; it is preferably carried out on the smoother side of the film

In the case of orientation, it is then used for partially crystalline materials

Temperatures below the Kπstallit melt temperature and, in the case of amorphous materials, tempered above the glass transition temperature and then stretched one or more times biaxially.After the stretching step or steps, the film can optionally be fixed in each case

Film may be surface-finished in m-line. The finishing can be carried out with a corona, a flame, a plasma or an oxidative substance or mixture of substances such that there is an increase in the surface tension on the film

The invention also relates to a method for stretching the

Foil The biaxial stretching can be carried out in the simultaneous stretching process or in the two-stage sequential process, where both first longitudinal and then transverse stretching and first transverse and then slow stretching, or in the three-stage sequential process, both longitudinal, then transverse and finally slow stretching as well as first crosswise, then longitudinally and finally laterally stretching, or in the four-stage sequential process, where both first longitudinally, then laterally, then longitudinally and finally laterally stretched, and first laterally, then longitudinally, then laterally and finally can be stretched slowly

The film may be attached to each individual stretching. The individual stretching in the longitudinal and transverse directions can be carried out in one or more stages In a preferred form of the film according to the invention, the biaxial stretching is characterized in that it is a sequential process which begins with the elongation.

In an even more preferred form of the film according to the invention, the biaxial stretching is characterized in that the total stretching ratio in the longitudinal direction is 1 1, 5 to 1 ^* 10 and the total stretching ratio in the transverse direction is 1 2 to 1 20

In an even more preferred form of the film according to the invention, the biaxial stretching is characterized in that the total stretching ratio in the longitudinal direction is 1 2.8 to 1 8 and the total stretching ratio in the transverse direction is 1 3.8 to 1 15

In an even more preferred form of the film according to the invention, it has a thickness which is <500 μm

A special embodiment of the films according to the invention is characterized in that the film has a total thickness between at least 30 μm and at most 200 μm. Films with a thickness of at least 50 μm and at most 100 μm are particularly suitable

The invention furthermore relates to the use of the film according to the invention. The use of this film as a solo film in pretreated or untreated as well as in printed or unprinted form is suitable for coating with PSAs. The film coated in this way is suitable, for example, as a label or adhesive strip The finishing stage is the application of wound dressings or drug release functions that are common with plasters

To improve pressure adhesion or adhesive anchoring, the film surface can be pretreated with a corona, a flame, a plasma or another oxidative substance or mixture of substances during production and / or subsequently during further processing, so that there is an increase in the surface tension In a particularly preferred form of use of this film according to the invention, only substances which are biodegradable and compostable are used to produce a plaster structure, so that the overall composite is also biodegradable and compostable.

The invention furthermore relates to the use of the film according to the invention as a starting material for the production of an adhesive tape or plaster with very high water vapor permeability, by piercing this film with a cold or tempered needle roller. The purpose of this film is the wound covering and protective film in the hygiene area

The invention is explained in more detail below with the aid of examples and comparative examples; the examples are compared with one another and with the comparative examples on the basis of the overview of relevant properties shown in Table 1.

example 1

In the first example, a two-layer film was produced by coextrusion on a blown film line. The extruders used for melting were operated with temperature programs of 130-145 ° C, the temperature of the blown film tool was 145 ° C

The formed film had a layer thickness sequence of 20 μm, 60 μm. Due to the inaccuracy of a thickness determined by mechanical scanning, which is caused by the roughening effect of the addition of the layered silicate according to the invention, the indicated thicknesses are nominal layer thicknesses, which arithmetically assume a smooth surface of the real rough, matted On the basis of the densities of the raw materials or the averaged densities of the raw material mixtures, these nominal layer thicknesses or the total nominal layer thickness can be calculated by adding the values obtained for the respective layers

The non-matted 60 μm thick layer that is used in film production

The outer layer (1) of the tube bladder was made from a compostable polyester amide. The polyester amide used was built up from the building blocks butanediol, adipic acid and caprolactam. It had a melt viscosity of 250 Pas at 190 ° C (measured according to DIN 5481 1-B) and a melting point of 125 ° C measured according to ISO 146 / C2 The density of the

Polyesteramids was 1.07 g / cm ³ , measured according to ISO 1 183

The outer layer formed from the polyester amide resin with the addition of lubricants was subjected to a corona treatment after the film production and a surface tension of 35 mN / m was achieved

The 20 μm thick inner layer (2) of the film was produced from a mixture consisting of 70% by weight of the polyester amide resin used for the 60 μm thick layer and 30% by weight of a layered silicate masterbatch. This masterbatch had a talcum content of 50% by weight The size of the talc particles was smaller than 22 μm. The melting temperature measured according to Dusenaustπtt was 152 ° C Example 2

A two-layer film structure with a total thickness of 51 μm made of biodegradable polyester amide with a melt viscosity of 250 Pas at 190 ° C (measured according to DIN 54 811-B) and a melting point of 125 ° C measured according to ISO 3146 / C2 was measured under the following process parameters biaxially stretched

The maximum extrusion temperature was 205 ° C

Correspondingly, the extruder temperature zones were heated to a maximum of 182 ° C and the mold to a maximum of 205 ° C. The melt was cooled as a two-layer flat film on a cooling roll mill at roll temperatures of 20 ° C. A solid thick film was formed, which in the next process step

Tempering rollers with temperatures of 65 ° C was heated to stretching temperature. The smooth layer (1) consisted of polyester amide with the addition of lubricants. It had a thickness of 39 μm

The matted layer (1) with a thickness of 12 μm was made from a mixture consisting of 80% by weight of that used for the 39 μm thick layer

Polyester amide resin and 20% by weight of a silica masterbatch The masterbatch had a silica content of 40% by weight. The size of the silica particles was <15 μm

The actual stretching rollers were operated at a temperature of 70 ° C. First the flat film was twisted in two stages

1 1.5 and then stretched in the longitudinal direction by the ratio of 1 2.5. The total stretching ratio in the longitudinal direction was thus 1. 3.75 The post-heating rollers over which the film then ran had a temperature of 85 ° C. The preheating zones of the The transverse stretching oven was heated to 100 ° C. The temperature in the actual transverse stretching part was 95 ° C

Ratio 1 5 stretched in the transverse direction This gave a calculated area stretch ratio of 1 18.75. After the transverse stretching, the film was fixed at a temperature of 105 ° C. The production speed at the outlet of the transverse stretch was 32.0 m / min Comparative Example A

Using a blown film tool, a single-layer film with a thickness of 100 μm was formed analogously to Example 1. The polyester amide resin used was lubricated.

Comparative Example B

Analogously to Example 2, a single-layer flat film made of polyester amide was oriented. The polyester amide resin was equipped with lubricants. The film thickness was 46 μm

The following physical properties and compostability were measured on the manufactured samples as follows

Mechanical properties ^*

The mechanical great tensile strength and elongation at break in both the longitudinal and transverse directions of the samples were determined in accordance with DIN 53 455. The modulus of elasticity in the longitudinal and transverse directions was determined in accordance with DIN 53 457. The thickness of the individual samples was determined in accordance with DIN 53 370

Optics

The surface gloss was determined as optical properties on the films in accordance with DIN 67 530 at a test angle of 20 °. The gloss measurement was carried out separately on both sides of the film.

Compostability:

The compostability was carried out in accordance with the test regulation of the DIN standard draft DIN 54 900 part 3 from 1996. Based on the test results, the film samples were classified into the appropriate class in accordance with the DIN recommendations

The results of the tests on the samples from Examples 1 and 2 and the

Comparative examples 1 and 2 are listed in Table 1 Table 1

Example 1 Example 2 Comparative Comparative Example 1 Example 2

Mechanical properties

Thickness [μm] 80 51 100 46

Young's modulus along [MPa] 280 255 270 226

E-module transverse [MPa] 323 305 350 292

Longitudinal tensile strength 54 92 55 90 [MPa]

Ultimate tensile strength 42 111 40 109 [MPa]

Elongation at break along 390 186 412 224 [%]

Elongation at break across [%] 630 98 654 111

Optics

Gloss [GE], matt 0.8 5 3.1 105 page

Gloss [GE], smoother 3.0 78 3.2 116 page

Compostability

Biodegradability yes yes yes yes

All of the films according to the invention listed in the examples have a reduced gloss compared to the films examined in the context of the comparative examples.

Claims

claims

1. At least two-layer compostable film, characterized in that the film according to the invention has a low tendency to curl and on one side has gloss values <10, measured according to DIN 67 530 at an angle of 20 °, the one having the lower gloss values

Outer layer of the film contains a proportion of 1-80% of substantially uniformly distributed filler, the average grain size of which is <22 μm and comprising polymers from the group as matrix materials of the individual layers of the polymer-resin layer structure

I. aliphatic and partially flavored polyesters

II. Aliphatic polyester urethanes

III. aliphatic-flavored polyester carbonates

IV. Aliphatic polyester amides

2. Film, according to claim 1, characterized in that it is in the or the biodegradable polymers to copolyesters from the

Groups of

I. aliphatic and partially aromatic polyester

A) linear bifunctional alcohols and / or optionally cycloaliphatic bifunctional alcohols and additionally, if appropriate, small amounts of higher-functionality alcohols and from linear bifunctional acids and / or optionally cycloaliphatic bifunctional acids and / or optionally aromatic bifunctional acids and additionally optionally small amounts of higher-functionality acids or

B) from acid and alcohol functionalized building blocks or their derivatives

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, or of II. Aliphatic polyester urethanes

C) an ester fraction from linear bifunctional alcohols and / or optionally cycloaliphatic bifunctional alcohols and additionally optionally small amounts of higher-functionality alcohols and from linear bifunctional acids and / or optionally cycloaliphatic and / or aromatic bifunctional acids and additionally optionally small amounts of higher-functional acids or

D) from an ester portion from acid and alcohol functionalized building blocks or their derivatives

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 isocyanates and additionally optionally high-functional isocyanates and, if appropriate, additionally with linear and / or cycloaliphatic bifunctional and / or highly functional alcohols,

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

III aliphatic-aromatic polyester carbonates look

F) an ester fraction from linear bifunctional alcohols and / or cycloaliphatic bifunctional alcohols and additionally, if appropriate, small amounts of higher-functionality alcohols and from linear bifunctional acids and / or optionally cycloaliphatic bifunctional acids and additionally, if appropriate, small amounts of higher-functionality acids or

G) from an ester portion of acid and alcohol functionalized building blocks or their derivatives

or a mixture or a copolymer of F) and G) and H) a carbonate fraction which is produced from aromatic bifunctional phenols and carbonate donors,

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

IV. Aliphatic polyester amides

I) an ester fraction from linear and / or cycloaliphatic bifunctional alcohols and additionally, if appropriate, small amounts of higher-functionality alcohols and from linear and / or cycloaliphatic bifunctional acids and additional, if appropriate, small amounts of higher-functionality acids or

K) from an ester portion of acid and alcohol functionalized building blocks or their derivatives

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

L) an amide content of linear and / or cycloaliphatic bifunctional and additionally, if appropriate, small amounts of higher-functionality amines and of linear and / or cycloaliphatic bifunctional and additionally optionally small amounts of higher-functionality acids or

M) from an amide portion of acid and amine functionalized building blocks

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).

3. Film according to one of claims 1 and / or 2, characterized in that silicas and / or silicates are used as filler. 4 film according to claims 1 and / or 2, characterized in that the individual layers of the film may contain further processing aids, silicates, waxes and colors being among the preferred additives

5 film according to at least one of the preceding claims, characterized in that it is polyester amides in the or the biodegradable and compostable polymers

6 A process for producing a film according to claims 1-5, characterized in that it is produced by extrusion

7 The method according to claim 6, characterized in that the film in

Is subjected to biaxial stretching in the course of the production

8. The method according to claim 7, characterized in that the total stretching ratio in the longitudinal direction is 1 1.5 to 1 10 and the total stretching ratio in the transverse direction is 1 2 to 1 20

9 Use of the film according to claims 1 to 5, characterized in that it is used as a solo film in pretreated or untreated as well as in printed or unprinted form with additional adhesive as a carrier film for labels, adhesive tapes and / or plasters