CA2262000A1 - Compostable backing foil - Google Patents
Compostable backing foil Download PDFInfo
- Publication number
- CA2262000A1 CA2262000A1 CA002262000A CA2262000A CA2262000A1 CA 2262000 A1 CA2262000 A1 CA 2262000A1 CA 002262000 A CA002262000 A CA 002262000A CA 2262000 A CA2262000 A CA 2262000A CA 2262000 A1 CA2262000 A1 CA 2262000A1
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- Prior art keywords
- acids
- optionally
- film
- bifunctional
- proportion
- Prior art date
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- Abandoned
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
- B29C55/10—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial
- B29C55/12—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
- B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
- B29K2995/0037—Other properties
- B29K2995/0059—Degradable
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B38/00—Ancillary operations in connection with laminating processes
- B32B38/0012—Mechanical treatment, e.g. roughening, deforming, stretching
- B32B2038/0028—Stretching, elongating
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2367/00—Polyesters, e.g. PET, i.e. polyethylene terephthalate
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2519/00—Labels, badges
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
- B32B37/14—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers
- B32B37/15—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer being manufactured and immediately laminated before reaching its stable state, e.g. in which a layer is extruded and laminated while in semi-molten state
- B32B37/153—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer being manufactured and immediately laminated before reaching its stable state, e.g. in which a layer is extruded and laminated while in semi-molten state at least one layer is extruded and immediately laminated while in semi-molten state
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 µm. 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.
(IV) aliphatic polyester amides.
Description
WW 5469-Foreign Br/by/S-P
Compostable supportin~ web The invention relates to biodegradable, particularly compostable films which aremanufactured by extrusion from the melt.
The invention relates to multi-layer, at least two-layer films with an asymmetrical layer structure and a low tendency to curl, which may be prepared by coextrusionand are obtained in the ple~aldlion process directly as matt films without further treatment stages. The films are composed of compostable polymers or copolymers 10 and contain, in one of the outer layers, relatively large amounts of mineral filler. Due to the unexpectedly similar volume contraction of the filled and unfilled layers of the at least two-layer film during the preparation process, the films according to the invention have an extremely low tendency to curl. In addition, they may contain proportions of processing auxiliaries, coloured pigments and stabilisers. As a result 15 of their silk-matt surface characteristics, said films are suitable for the low-gloss covering of surfaces. They may be used, for example as supporting films for adhesive plasters, sticking plasters or plaster strips.
The films according to the invention are suitable for a multiplicity of applications, 20 the use as supporting films for adhesive plasters being emphasised here in particular.
Adhesive plasters are generally composed of a supporting material, coated with apressure-sensitive adhesive, a wound cover which has a smaller surface area than the supporting material, and a release material which protects pressure-sensitive adhesive and wound cover during storage. Films for such applications have to meet a 25 multiplicity of requirements, aesthetic as well as technical requirements having to be satisfied in particular.
Films for medical plasters have to be dimensionally stable and able to withstand a chemical or physical pretreatment in order to be printed and/or coated.
WW 5469-Foreign The aesthetic requirements include primarily a silk-matt surface which guarantees a skin-like appearance. Matt surfaces are generally assessed by gloss, and minim~lgloss values are desired. Generally speaking, gloss values of <10 have proved acceptable for plasters, measured in accordance with DIN 67 530, at an angle of 20~.
S The tactile properties of plaster films must also be attractive, said properties including in particular a soft feel.
In the use of a cut-to-size plaster piece, the load due to tensile forces remains small in practice since the pressure-sensitive adhesive has particularly low adhesion to a 10 conventionally used release material such as, for example, silicone-coated paper or rigid films. Cut-to-size plaster pieces differ in this context from rolls of plaster where relatively high pull forces may occur since a release layer is dispensed with in this case and the adhesive layer is situated on the outside of the plaster.
15 Similarly, films for rolls of plaster are not very soft materials. When a longitudinal load is applied of the kind that occurs e.g. during removal as an adhesive tape from the roll, low longitudinal expansion is desirable and generally obtained.
To this extent, not only are the high ultimate tensile stress values or elongation at 20 break values important for characterising a suitable film material for use assupporting film for cut-to-size plaster pieces, but also the initial elongation values in the event of a tensile stress are important criteria of assessment.
In the past, matt-calendered polyvinyl chloride (PVC) films were used in many cases 25 as supporting films. The public discussion about the effects on health of the vinyl chloride monomer and the so-called external plasticisers, criticism focusing on the phthalate plasticisers in particular, intensified the pressure to replace plasticised PVC.
30 The requirements in respect of films for medical plasters are set out, for exarnple, in the German utility model applications GM 90 12 161.9 and GM 93 06 768.2 (both WW 5469-Foreign Beiersdorf). The classification of plasters is regulated by the relevant ph~rm~copoeias, this being for example the DAB 10 (1991) in Germany.
It is known that certain polymer materials are subject to biological degradation.
5 These mainly include materials which are obtained from naturally occurring polymers directly or after modification, for example, polyhydroxyalkanoates such as polyhydroxybutyrate, plastic celluloses, cellulose esters, plastic starches, chitin and pullulan. A controlled variation of the polymer composition or of the structures, of the kind that is desirable from the point of view of the polymer application, is10 difficult to achieve in view of the natural synthesis process and often achieved only to a very limited degree.
Many of the synthetic polymers, on the other hand, are attacked only extremely slowly by microorg~ni~m~, if at all. Mainly synthetic polymers containing 15 heteroatoms in the main chain are regarded as potentially biodegradable. An important class within these materials are the polyesters. Synthetic raw materials containing only aliphatic monomers have relatively good biodegradability but because of their material properties can be used only to an extremely limited degree;
cf. Witt et al. in Macrom. Chem. Phys., 195 ( 1994) p. 793 - 802. Aromatic 20 polyesters, on the other hand, exhibit markedly worse biodegradability whilst having good material properties.
Various biodegradable polymers have become known recently (see DE 44 32 161).
These have the property of being highly melt processable and on the other hand 25 biodegradable, i.e. their whole polymer chain is cleaved by microorg~ni~m~ (bacteria and fungi) by way of enzymes and degraded completely to carbon dioxide, water and biomass. A corresponding test in the natural environment with the action of microorg~ni.~m~, of the kind predomin~ting i.a. in a compost, is given i.a. in DIN 54 900.
WW 5469-Forei~n The object of the present invention is to provide melt processable and fully biodegradable plastic films with fillers such that no synthetic materials remain in the compost and which have a good range of mechanical properties, particularly strength and impact resistance.
The object was to provide a matt film obtainable from the film preparation process without further mechanical treatment stages. In order to guarantee simple further processing to supporting films for cut-to-size plaster pieces, the film was to have a low tendency to curl. From an ecological standpoint, the film according to the 10 invention was to be free from halogen compounds and aromatic plasticisers with a comparatively low molecular weight. It was to have at least one adhesive-tolerant side so that it can be coated without difficulty with a pressure-sensitive adhesive on common transfer l~min~ting machines. In addition, the film was to be elastic so that it can adjust in a flexible manner to skin movements in the wound area. Very largely 15 isotropic properties in the film plane are an advantage for the use of the film on the widest possible scale.
The object is achieved by incorporating mineral fillers in at least one layer of a multi-layer film to be prepared from thermoplastic, biodegradable moulding 20 compositions.
The present invention thus provides rigid and yet biodegradable plastic films, characterised in that mineral fillers, particularly of natural origin, which areincorporated in the melt in fully biodegradable polymers, are used as base material 25 of at least one outer layer of the film. Accordingly, the present invention is to be regarded as providing a biodegradable and compostable film with improved mechanical and optical properties. The terms "biodegradable and compostable polymers or films" within the meaning of this invention mean materials whose biodegradability is tested according to the test of DIN 54 900 from the 1996 draft.
WW 5469-Foreign The film according to the invention is obtained preferably by processing from the melt, the various layers exhibiting only minor differences in their volume contraction on cooling so that a structure with a low tendency to curl is obtained.
The film according to the invention may contain the additives customary in plastics 5 processing.
The invention also provides a film which has biaxial orientation and is composed of one or more polymers which are all biodegradable and compostable, and possibly contains additional additives for improving processability. Biaxial orientation is 10 carried out in the case of amorphous thermoplastics in temperature ranges above the glass transition temperature and in the case of partially crystalline thermoplastics below the crystalline melting point.
The invention also provides the use of the matt compostable films as supporting web 15 of adhesive tapes which are coated on one side with the pressure-sensitive adhesives known according to the prior art. In particular, this relates to adhesive tapes which are further processed to adhesive plasters or active ingredient plasters.
The layer structure according to the invention is formed from at least one layer (I) of 20 a compostable polymer and/or a compostable copolymer and/or mixtures thereof,this taking place optionally with the addition of suitable colorants and stabilisation additives in effective amounts, and at least a second matt layer (2).
Layer (2) is characterised in that said layer has compostable polymers as matrix, i.e.
25 in a majority proportion, and is flatted by the addition of a filler. The matrix material used in preference for layer (2) is the same polymer as for layer (1). Further layers (3) may optionally be arranged between layers (1) and (2), said further layers being formed in turn preferably from a compostable matrix resin.
30 Suitable polymers are:
, _ .
WW 5469-Foreign aliphatic and partly aromatic polyesters of A) linear bifunctional alcohols, for example, ethylene glycol, hexane diol or preferably butane diol, and/or optionally cycloaliphatic bifunctional alcohols, for example, cyclohexane dimethanol and, in addition, optionally small amounts of higher-functionality alcohols, for example, 1,2,3-propane triol or neopentyl glycol, and of linear bifunctional acids, for example, succinic acid or adipic acid, and/or optionally cycloaliphatic bifunctional acids, for example, cyclohexane dicarboxylic acid, and/or optionally aromatic bifunctional acids, for example, terephthalic acid or isophthalic acid or naphthalene dicarboxylic acid and, in addition, optionally small amounts of higher-functionality acids, for example trimellitic acid, or B) acid- and alcohol-functionalised building blocks, for example, hydroxybutyric acid or hydroxyvaleric acid or derivatives thereof, for example, ~-caprolactone, or a mixture or a copolymer of A) and B) wherein the aromatic acids account for a proportion of not more than 50 wt.%, based on all the acids.
The acids may also be used in the form of derivatives, for example, acid chlorides or esters.
Aliphatic polyester urethanes of C) an ester proportion of linear bifunctional alcohols, for example, ethylene glycol, butane diol, hexane diol, preferably butane diol, and/or optionally cycloaliphatic bifunctional alcohols, for example, cyclohexane dimethanol and, in addition, optionally small amounts of higher-functionality alcohols, WW 5469-Foreign for example, 1,2,3-propane triol or neopentyl glycol, and of linear bifunctional acids, for example, succinic acid or adipic acid, and/or optionally cycloaliphatic and/or aromatic bifunctional acids, for example, cyclohexane dicarboxylic acid and terephthalic acid and, in addition, optionally small amounts of higher-functionality acids, for example trimellitic acid, or D) an ester proportion of acid- and alcohol-functionalised building blocks, for example, hydroxybutyric acid and hydroxyvaleric acid or derivatives thereof, for example, ~-caprolactone, or a mixture or a copolymer of C) and D), and E) the reaction product of C) and/or D) with aliphatic and/or cycloaliphatic bifunctional isocyanates and, in addition, optionally higher-functionality isocyanates, for example, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and optionally, in addition, with linear and/or cycloaliphatic bifunctional and/or higher-functionality alcohols, for example, ethylene glycol, butane diol, hexane diol, neopentyl glycol, cyclohexane dimethanol, wherein the ester proportion C) and/or D) is at least 75 wt.%, based on the sum of C), D) and E).
25 Aliphatic-aromatic polyester carbonates of F) an ester proportion of linear bifunctional alcohols, for example, ethylene glycol, butane diol, hexane diol, preferably butane diol, and/or cycloaliphatic bifunctional alcohols, for example, cyclohexane dimethanol and, in addition, optionally small amounts of higher-functionality alcohols, for example, 1,2,3-propane triol or neopentyl glycol, and of linear bifunctional acids, for WW 5469-Foreign example, succinic acid or adipic acid, and/or optionally cycloaliphatic bifunctional acids, for example, cyclohexane dicarboxylic acid and, in addition, optionally small amounts of higher-functionality acids, for example trimellitic acid, or s G) an ester proportion of acid- and alcohol-functionalised building blocks, for example, hydroxybutyric acid or hydroxyvaleric acid or derivatives thereof, for example, ~-caprolactone, or a mixture or a copolymer of F) and G) and H) a carbonate proportion which is prepared from aromatic bifunctional phenols, preferably bisphenol A and carbonate donors, for example, phosgene, wherein the ester proportion F) and/or G) is at least 70 wt.% based on the sum of F), G) and H).
Aliphatic polyester amides of 20 I) an ester proportion of linear and/or cycloaliphatic bifunctional alcohols, for example, ethylene glycol, hexane diol or butane diol, preferably butane diol, or cyclohexane dimethanol and, in addition, optionally small amounts of higher-functionality alcohols, for example, 1,2,3-propane triol or neopentyl glycol, and of linear and/or cycloaliphatic bifunctional acids, for example, succinic acid, adipic acid, cyclohexane dicarboxylic acid, preferably adipic acid and, in addition, optionally small amounts of higher-functionality acids, for example trimellitic acid, or K) an ester proportion of acid- and alcohol-functionalised building blocks, for example, hydroxybutyric acid or hydroxyvaleric acid or derivatives thereof, for example, ~-caprolactone, .. . . . .
WW 5469-Forei~n g or a mixture or a copolymer of I) and K) and L) an amide proportion of linear and/or cycloaliphatic bifunctional and, in S addition, optionally small amounts of higher-functionality amines, forexample tetramethylene (1i~mine, hexamethylene diamine, isophorone diamine, and of linear and/or cycloaliphatic bifunctional acids and, in addition, optionally small amounts of higher-functionality acids, for example, succinic acid or adipic acid, or M) an amide proportion of acid- and amine-functionalised building blocks, preferably c3-laurinlactam and in particular preference ~-caprolactam, or a mixture of L) and M) as amide proportion, wherein the ester proportion I) and/or K) is at least 30 wt.% based on the sum of I), K), L) and M).
The biodegradable and compostable raw materials according to the invention may be 20 furnished with processing auxiliaries and additives such as, for example, nucleating agents (for example, 1,5-naphthalene disodium sulfonate), stabilisers or lubricants.
The biodegradable copolyesters, polyester urethanes, polyester carbonates and polyester amides have a molecular weight of at least 10,000 g/mole and have a 25 random distribution of the starting materials (monomers) in the polymer.
The biodegradable polymers mentioned are preferably polyester urethanes and polyester carbonates and particularly preferably polyester amides.
30 The invention also provides the use of a certain class of materials of biodegradable and compostable polymers for the plepaldlion of the film, said class of materials WW 5469-Foreign being polyester amide. The film according to the invention may be prepared from a polyester amide or a mixture of various polyester amides.
Suitable flatting agents for layer (1) of the film according to the invention are 5 minerals which are used in the form of powder, as is customary for incorporation in non-biodegradable thermoplastics.
The mineral fillers include, for example and in preference gypsum, wollastonite and in particular preference chalk and kaolin. Natural and synthetic silicas are likewise to 10 be regarded as suitable. Layer silicates are particularly suitable.
The thermoplastic moulding compositions according to the invention for layer (1)contain 1 wt.% to 80 wt.%, preferably 10 wt.% to 60 wt.%, particularly preferably 20 wt.% to 40 wt.% of minerals, preferably of natural origin.
The layer silicate proportion of the matt layer of the film according to the invention should be, in a particularly preferred embodiment, advantageously at least 10 wt.%, so that a marked flatting is obtained and on the other hand it should not exceed 25 wt.%. Surprisingly, no appreciable impairment of the mechanical strength occurs in 20 this case.
The invention also provides a process for the preparation of the reinforced thermoplastic moulding compositions according to the invention, characterised inthat the fillers are intim~tely mixed with the biodegradable polymer, e.g. in a 25 kneader or preferably an extruder.
It is generally advantageous, mainly from an economic angle, if the matt layer accounts for a small proportion of the total layer thickness of the film flatted on one side. Consequently, thickness combinations in which the proportion of the layer 30 flatted with layer silicate is 15 - 40% of the total layer thickness are of particular interest.
WW 5469-Forei~n The addition of the flatting layer silicate is carried out preferably in the form of an additive masterbatch which, in a particularly preferred embodiment, has a weightproportion of layer silicate between 30 and 80 wt.%. A smaller proportion has 5 economic disadvantages whilst a higher proportion of layer silicate in the masterbatch brings about a poor distribution which becomes appale~ll, for example, in undesirable silicate agglomerates. This causes a more uneven rollghn~cs and hence less pleasant tactile properties.
10 Compostable polymers or compostable copolymers with colllpalalively high meltflow indices between 8 and 24 g/10 min, measured in accordance with DIN 53 735 at 190~C and under a test load of 2.16 kg, have proved to be suitable for the preparation of such additive masterbatches. In order to be able to improve the masterbatch homogeneity, further plasticising auxiliaries such as, e.g., waxes, may 15 optionally be contained. To prevent thermal damage of the polymer component of the masterbatch, the latter are usually furnished with stabilisers.
In a preferred embodiment, individual or all layers of the multi-layer-film according to the invention may be modified by the further addition of processing aids, fillers, 20 colorants and stabilisers. Colorants permit the production of plasters for special fields of application.
In one of these selected embodiments, at least one of the layers contains coloured pigments. Beige-coloured film is popular if wound and wound cover are not to be 25 openly visible. Bright colourings and printing applications are used in many cases in children's plasters. Further additives such as silicates and waxes modify the application properties, particularly the surface slip behaviour. Stabilisers make it possible to keep the films according to the invention over a lengthy period and to prevent damage during processing. The common additives for plastics are described 30 by Gachter and Muller in: Handbuch der Kunststoff Additive, Hanser Verlag, Munich 1983.
WVV 5469-Foreign The invention also provides processes for the plepalalion of the film according to the mventlon.
5 Said processes are characterised in that the biodegradable and compostable material(s) are initially broken down by the effect of heat and shear, the melt streams are placed one over the other in a die and discharged and cooled until solidification.
This may be carried out by conventional processes of flat or blown film extrusion.
10 Said processes are described, for example, by Michaeli in: Extrusionswerkzeuge fur Kunststoffe und Kautschuk, Carl Hanser Verlag, Munich 1991. Further information is given in Handbuch der Kunststoff Extrusionstechnik, published by Hensen, Knappe and Potente, Carl Hanser Verlag, Munich 1989.
15 The winding of the film, and also a further treatment by heating and/or orientation and/or a surface treatment on one or both sides may take place immediately afterwards.
With regard to their later use, the films according to the invention may be modified 20 in terms of their surface properties by a surface treatment process. Corona, plasma or fluorine and flame treatments are particularly suitable for this purpose. Such processes were described in detail, for example, by Dorn and Wahono in Maschinenmarkt 96 (1990) 34-39 or Milker and Moller in Kunststoffe 82 (1992) 978-981. A preferred process is the corona treatment.
In the corona treatment, the procedure is advantageously such that the film is passed between two conducting elements acting as electrodes, whereby such a high current -usually alternating current of about 10 kV with a frequency of 10 kHz - is applied between the electrodes that corona discharges can take place. As a result of these 30 discharges, the air along the film surface is ionised so that reactions take place on the film surface during which polar groups are produced in comparison with the WW 5469-Foreign polymer matrix. The treatment intensities required for the pretreatment of the films according to the invention lie within the usual bounds, treatment intensities that yield surface tensions from 38 to 50 mN/m being preferred.
5 The films according to the invention may be pretreated on one or both sides. The purpose of such treatments is to improve the surfaces in terms of their properties of adhesion to the printing and/or coating materials. In the case of plasters, conventional printing applications are, for example, brightly coloured ~nim~l~ or articles which are printed preferably on the matter side of children's plasters. The 10 coating with pressure-sensitive adhesives is generally a conventional process with plasters, and takes place preferably on the smoother side of the film.
In the case of orientation, heating in the case of partially crystalline materials takes place to temperatures below the crystalline melting point and in the case of 15 amorphous materials to above the glass transition temperature, followed by one or more biaxial orientation operations. After the orientation stage(s), a fixing of the film may optionally be carried out in each case. After the orientation processes and the possibly predominant fixing stages, the film thus manufactured may optionally be surface-treated in line. The treatment may be carried out with a corona, flame, 20 plasma or an oxidative substance or mixture of substances such that an increase in the surface tension on the film is obtained.
The invention also provides a process for orienting the film. Biaxial orientation may be carried out in a simultaneous stretching process or in a two-stage sequential25 process wherein both longitudinal followed by transverse stretching and transverse followed by longitudinal stretching may take place, or in a three-stage sequential process wherein both longitudinal followed by transverse and finally longitudinal stretching and transverse followed by longitudinal and finally transverse stretching may take place, or in a four-stage sequential process wherein both longitudinal 30 followed by transverse followed by longitudinal and finally transverse stretching and WW 5469-Foreign transverse followed by longitudinal followed by transverse and finally longitudinal stretching may take place.
Each individual orientation may optionally be followed by a fixing of the film. The individual orientation in a longitudinal and transverse direction may take place in one or more stages in this case.
In a preferred form of the film according to the invention, biaxial orientation is characterised in that it is a sequential process that starts with longitudinal stretching.
In an even more preferred form of the film according to the invention, biaxial orientation is characterised in that the total stretch ratio in the longitudinal direction is 1: 1.5 to 1: 10 and the total stretch ratio in the transverse direction is 1: 2 to 1:
20.
In an even more preferred form of the film according to the invention, biaxial orientation is characterised in that the total stretch ratio in the longitudinal direction is 1: 2.8 to 1: 8 and the total stretch 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, said film has a thickness of < 500 llm.
A particular embodiment of the films according to the invention is characterised in that the film has a total thickness between at least 30 ~Lm and at most 200 ~m. Films with a thickness of at least 50 ~lm and at most 100 ~m are particularly suitable.
The invention also provides the use of the film according to the invention. A suitable application is the use of said film as a solo film in pretreated or non-pretreated and in printed or unprinted form for coating with pressure-sensitive adhesives. The film coated in this way is suitable, for example, as a label or adhesive strip. A further WW 5469-Foreign fini~hing stage is the provision of wound coverings or active substance release functions which are customary with plasters.
In order to improve printing adhesion or anchoring of the adhesive, the film surface 5 may be pretreated during preparation and/or afterwards during further processing with a corona, flame, plasma or another oxidative substance or mixture of substances such that an increase in the surface tension is obtained.
In a particularly preferred use of said film according to the invention, only 10 substances which are biodegradable and compostable are used to prepare a plaster structure, so that the entire composite is likewise biodegradable and compostable.
The invention also provides the use of the film according to the invention as starting material for the ~repaldlion of an adhesive tape or plaster with very high water15 vapour permeability, said film being pierced with a cold or heated spiked roller. The intended use of said film is wound covering and protective film in the hygiene sector.
The invention is explained in even more detail below on the basis of examples and 20 comparative examples, and a comparison of the examples with one another and with the comparative examples is made on the basis of the summary of relevant properties shown in Table 1.
WW 5469-Fore;~n Example 1 Within the context of the first example a two-layer film was produced by coextrusion on a blown film unit. The extruders used for melting were operated with temperature programmes of 130 - 145~C, the temperature of the blown film die being 145~C.
The formed film had a layer thickness sequence of 20 ~m, 60 ~lm. In view of the inaccuracy of a thickness determined by mechanical sc~nning due to the roughening effect of the addition of layer silicate according to the invention, the stated thicknesses are nominal layer thicknesses which were determined by calculation on the assumption of a smooth surface of what was actually the rough, matt side. On the basis of the densities of the raw materials and the averaged densities of the raw material mixtures, these nominal layer thicknesses and the total nominal layer thickness can be calculated by adding the values obtained for the respective layers.
The non-matt 60 llm thick layer which formed the outer layer (1) of the film bubble during film production was produced from a compostable polyester amide. The polyester amide used was composed of the building blocks butane diol, adipic acid and caprolactam. It had a melt viscosity of 250 Pas at 190~C (measured in accordance with DIN 54811-B) and a melting point of 125~C, measured in accordance with ISO 3146/C2. The density of the polyester amide was 1.07 g/cm3, measured in accordance with ISO 1183.
The outer layer formed from the polyester amide resin with the addition of lubricants underwent a corona treatment after film production, and a surface tension of 35 mN/m was obtained.
The 20 ~m thick inner layer (2) of the film was produced from a mixture composedof 70 wt.% of the polyester amide resin used for the 60 ~m thick layer and 30 wt.%
of a layer silicate masterbatch. Said masterbatch had a talc proportion of 50 wt.%.
WW 5469-Foreign The size of the talc particles was less than 22 ~lm. The melt temperature measured after the die exit was 152~C.
Example 2 A two-layer film structure with a total thickness of 51 ~Lm of biodegradable polyester amide with a melt viscosity of 250 Pas at 190~C (measured in accordance with DIN54 811 - B) and a melting point of 125 ~C measured in accordance with ISO
3146/C2 was biaxially oriented under the following process parameters. The maximum extrusion temperature was 205~C.
Accordingly, the extruder heating zones were heated to a maximum of 182~C and the die to a maximum of 205~C. The melt was cooled as a two-layer flat film on chill rolls at roll temperatures of 20~C. A rigid thick film was obtained which was heated to orientation temperature in the next process stage by means of heating rolls with temperatures of 65~C. The smooth layer (1) was composed of polyester amide with the addition of lubricants. It had a thickness of 39 ~m.
The matt layer (1) with a thickness of 12 llm was prepared from a mixture composed of 80 wt.% of the polyester amide resin used for the 39 llm thick layer and 20 wt.%
of a silica masterbatch. The masterbatch had a silica proportion of 40 wt.%. The size of the silica particles was < 15 llm.
The actual stretching rolls were operated at a temperature of 70~C. Initially, the flat film was stretched longitudinally in two stages firstly by the ratio 1: 1.5 and then by the ratio 1: 2.5. A total stretch ratio of 1: 3.75 was thus obtained in the longitudinal direction. The post-heating rolls over which the film then passed had a temperature of 85~C. The pre-heating zones of the transverse stretching oven were heated to 100~C. The temperature in the actual transverse stretching part was 95~C. Here the film was stretched in the transverse direction by the ratio of 1: 5 . By calculation, a surface stretch ratio of 1: 18.75 was thus obtained. After transverse stretching, the ~W 5469-Forei~n film was fixed at a temperature of 105~C. The production speed at the outlet of transverse stretching was 32.0 m/min.
Comparative example A
A single-layer film with a thickness of 100 ~lm was formed with a blown film die as in Example 1. The polyester amide resin used was furnished with lubricants.
Comparative example B
A single-layer flat film of polyester amide was oriented as in Example 2. The polyester amide resin was furnished with lubricants. The film thickness was 46 llm.
The following physical properties and compostability were measured as follows onthe samples produced.
Mechanical properties:
The mechanical variables ultimate tensile strength and elongation at break were determined on the samples both in the longitudinal and in the transverse direction according to DIN 53 455. The E-modulus in the longitudinal and transverse direction was determined according to DIN 53 457. The thickness of the individual samples was determined according to D~N 53 370.
Optical properties:
The optical properties determined on the films were the surface gloss according to 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 specification of the D~N draft standard DIN 54 900 part 3 of 1996. On the basis of the test results, the WW 5469-Forei~n classification of the film samples in the apl)ropliate class is carried out according to the DIN recommendations.
The results of the tests on the samples from Example 1 and 2 and comparative 5 examples I and 2 are given in Table 1.
Table 1 Example Example Comparative Comparative 2 example 1 example2 Mechanical properties Thickness [~m] 80 51 100 46 E-modulus long. [MPa] 280 255 270 226 E-modulus transv. [MPa] 323 305 350 292 Ultimate tensile 54 92 SS 90 strength long. [MPa]
Ultimate tensile 42 111 40 109 strength transv. [MPa]
Elongation at break 390 186 412 224 long. [%]
Elongation at break 630 98 654 111 transv. [%]
Optical properties Gloss [GU], matter side 0.8 S 3.1 105 Gloss [GU], smoother side 3.0 78 3.2 116 Compostability yes yes yes yes Biodegradability All the films according to the invention given in the examples have reduced gloss 10 compared with the films examined within the context of the comparative examples.
Compostable supportin~ web The invention relates to biodegradable, particularly compostable films which aremanufactured by extrusion from the melt.
The invention relates to multi-layer, at least two-layer films with an asymmetrical layer structure and a low tendency to curl, which may be prepared by coextrusionand are obtained in the ple~aldlion process directly as matt films without further treatment stages. The films are composed of compostable polymers or copolymers 10 and contain, in one of the outer layers, relatively large amounts of mineral filler. Due to the unexpectedly similar volume contraction of the filled and unfilled layers of the at least two-layer film during the preparation process, the films according to the invention have an extremely low tendency to curl. In addition, they may contain proportions of processing auxiliaries, coloured pigments and stabilisers. As a result 15 of their silk-matt surface characteristics, said films are suitable for the low-gloss covering of surfaces. They may be used, for example as supporting films for adhesive plasters, sticking plasters or plaster strips.
The films according to the invention are suitable for a multiplicity of applications, 20 the use as supporting films for adhesive plasters being emphasised here in particular.
Adhesive plasters are generally composed of a supporting material, coated with apressure-sensitive adhesive, a wound cover which has a smaller surface area than the supporting material, and a release material which protects pressure-sensitive adhesive and wound cover during storage. Films for such applications have to meet a 25 multiplicity of requirements, aesthetic as well as technical requirements having to be satisfied in particular.
Films for medical plasters have to be dimensionally stable and able to withstand a chemical or physical pretreatment in order to be printed and/or coated.
WW 5469-Foreign The aesthetic requirements include primarily a silk-matt surface which guarantees a skin-like appearance. Matt surfaces are generally assessed by gloss, and minim~lgloss values are desired. Generally speaking, gloss values of <10 have proved acceptable for plasters, measured in accordance with DIN 67 530, at an angle of 20~.
S The tactile properties of plaster films must also be attractive, said properties including in particular a soft feel.
In the use of a cut-to-size plaster piece, the load due to tensile forces remains small in practice since the pressure-sensitive adhesive has particularly low adhesion to a 10 conventionally used release material such as, for example, silicone-coated paper or rigid films. Cut-to-size plaster pieces differ in this context from rolls of plaster where relatively high pull forces may occur since a release layer is dispensed with in this case and the adhesive layer is situated on the outside of the plaster.
15 Similarly, films for rolls of plaster are not very soft materials. When a longitudinal load is applied of the kind that occurs e.g. during removal as an adhesive tape from the roll, low longitudinal expansion is desirable and generally obtained.
To this extent, not only are the high ultimate tensile stress values or elongation at 20 break values important for characterising a suitable film material for use assupporting film for cut-to-size plaster pieces, but also the initial elongation values in the event of a tensile stress are important criteria of assessment.
In the past, matt-calendered polyvinyl chloride (PVC) films were used in many cases 25 as supporting films. The public discussion about the effects on health of the vinyl chloride monomer and the so-called external plasticisers, criticism focusing on the phthalate plasticisers in particular, intensified the pressure to replace plasticised PVC.
30 The requirements in respect of films for medical plasters are set out, for exarnple, in the German utility model applications GM 90 12 161.9 and GM 93 06 768.2 (both WW 5469-Foreign Beiersdorf). The classification of plasters is regulated by the relevant ph~rm~copoeias, this being for example the DAB 10 (1991) in Germany.
It is known that certain polymer materials are subject to biological degradation.
5 These mainly include materials which are obtained from naturally occurring polymers directly or after modification, for example, polyhydroxyalkanoates such as polyhydroxybutyrate, plastic celluloses, cellulose esters, plastic starches, chitin and pullulan. A controlled variation of the polymer composition or of the structures, of the kind that is desirable from the point of view of the polymer application, is10 difficult to achieve in view of the natural synthesis process and often achieved only to a very limited degree.
Many of the synthetic polymers, on the other hand, are attacked only extremely slowly by microorg~ni~m~, if at all. Mainly synthetic polymers containing 15 heteroatoms in the main chain are regarded as potentially biodegradable. An important class within these materials are the polyesters. Synthetic raw materials containing only aliphatic monomers have relatively good biodegradability but because of their material properties can be used only to an extremely limited degree;
cf. Witt et al. in Macrom. Chem. Phys., 195 ( 1994) p. 793 - 802. Aromatic 20 polyesters, on the other hand, exhibit markedly worse biodegradability whilst having good material properties.
Various biodegradable polymers have become known recently (see DE 44 32 161).
These have the property of being highly melt processable and on the other hand 25 biodegradable, i.e. their whole polymer chain is cleaved by microorg~ni~m~ (bacteria and fungi) by way of enzymes and degraded completely to carbon dioxide, water and biomass. A corresponding test in the natural environment with the action of microorg~ni.~m~, of the kind predomin~ting i.a. in a compost, is given i.a. in DIN 54 900.
WW 5469-Forei~n The object of the present invention is to provide melt processable and fully biodegradable plastic films with fillers such that no synthetic materials remain in the compost and which have a good range of mechanical properties, particularly strength and impact resistance.
The object was to provide a matt film obtainable from the film preparation process without further mechanical treatment stages. In order to guarantee simple further processing to supporting films for cut-to-size plaster pieces, the film was to have a low tendency to curl. From an ecological standpoint, the film according to the 10 invention was to be free from halogen compounds and aromatic plasticisers with a comparatively low molecular weight. It was to have at least one adhesive-tolerant side so that it can be coated without difficulty with a pressure-sensitive adhesive on common transfer l~min~ting machines. In addition, the film was to be elastic so that it can adjust in a flexible manner to skin movements in the wound area. Very largely 15 isotropic properties in the film plane are an advantage for the use of the film on the widest possible scale.
The object is achieved by incorporating mineral fillers in at least one layer of a multi-layer film to be prepared from thermoplastic, biodegradable moulding 20 compositions.
The present invention thus provides rigid and yet biodegradable plastic films, characterised in that mineral fillers, particularly of natural origin, which areincorporated in the melt in fully biodegradable polymers, are used as base material 25 of at least one outer layer of the film. Accordingly, the present invention is to be regarded as providing a biodegradable and compostable film with improved mechanical and optical properties. The terms "biodegradable and compostable polymers or films" within the meaning of this invention mean materials whose biodegradability is tested according to the test of DIN 54 900 from the 1996 draft.
WW 5469-Foreign The film according to the invention is obtained preferably by processing from the melt, the various layers exhibiting only minor differences in their volume contraction on cooling so that a structure with a low tendency to curl is obtained.
The film according to the invention may contain the additives customary in plastics 5 processing.
The invention also provides a film which has biaxial orientation and is composed of one or more polymers which are all biodegradable and compostable, and possibly contains additional additives for improving processability. Biaxial orientation is 10 carried out in the case of amorphous thermoplastics in temperature ranges above the glass transition temperature and in the case of partially crystalline thermoplastics below the crystalline melting point.
The invention also provides the use of the matt compostable films as supporting web 15 of adhesive tapes which are coated on one side with the pressure-sensitive adhesives known according to the prior art. In particular, this relates to adhesive tapes which are further processed to adhesive plasters or active ingredient plasters.
The layer structure according to the invention is formed from at least one layer (I) of 20 a compostable polymer and/or a compostable copolymer and/or mixtures thereof,this taking place optionally with the addition of suitable colorants and stabilisation additives in effective amounts, and at least a second matt layer (2).
Layer (2) is characterised in that said layer has compostable polymers as matrix, i.e.
25 in a majority proportion, and is flatted by the addition of a filler. The matrix material used in preference for layer (2) is the same polymer as for layer (1). Further layers (3) may optionally be arranged between layers (1) and (2), said further layers being formed in turn preferably from a compostable matrix resin.
30 Suitable polymers are:
, _ .
WW 5469-Foreign aliphatic and partly aromatic polyesters of A) linear bifunctional alcohols, for example, ethylene glycol, hexane diol or preferably butane diol, and/or optionally cycloaliphatic bifunctional alcohols, for example, cyclohexane dimethanol and, in addition, optionally small amounts of higher-functionality alcohols, for example, 1,2,3-propane triol or neopentyl glycol, and of linear bifunctional acids, for example, succinic acid or adipic acid, and/or optionally cycloaliphatic bifunctional acids, for example, cyclohexane dicarboxylic acid, and/or optionally aromatic bifunctional acids, for example, terephthalic acid or isophthalic acid or naphthalene dicarboxylic acid and, in addition, optionally small amounts of higher-functionality acids, for example trimellitic acid, or B) acid- and alcohol-functionalised building blocks, for example, hydroxybutyric acid or hydroxyvaleric acid or derivatives thereof, for example, ~-caprolactone, or a mixture or a copolymer of A) and B) wherein the aromatic acids account for a proportion of not more than 50 wt.%, based on all the acids.
The acids may also be used in the form of derivatives, for example, acid chlorides or esters.
Aliphatic polyester urethanes of C) an ester proportion of linear bifunctional alcohols, for example, ethylene glycol, butane diol, hexane diol, preferably butane diol, and/or optionally cycloaliphatic bifunctional alcohols, for example, cyclohexane dimethanol and, in addition, optionally small amounts of higher-functionality alcohols, WW 5469-Foreign for example, 1,2,3-propane triol or neopentyl glycol, and of linear bifunctional acids, for example, succinic acid or adipic acid, and/or optionally cycloaliphatic and/or aromatic bifunctional acids, for example, cyclohexane dicarboxylic acid and terephthalic acid and, in addition, optionally small amounts of higher-functionality acids, for example trimellitic acid, or D) an ester proportion of acid- and alcohol-functionalised building blocks, for example, hydroxybutyric acid and hydroxyvaleric acid or derivatives thereof, for example, ~-caprolactone, or a mixture or a copolymer of C) and D), and E) the reaction product of C) and/or D) with aliphatic and/or cycloaliphatic bifunctional isocyanates and, in addition, optionally higher-functionality isocyanates, for example, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and optionally, in addition, with linear and/or cycloaliphatic bifunctional and/or higher-functionality alcohols, for example, ethylene glycol, butane diol, hexane diol, neopentyl glycol, cyclohexane dimethanol, wherein the ester proportion C) and/or D) is at least 75 wt.%, based on the sum of C), D) and E).
25 Aliphatic-aromatic polyester carbonates of F) an ester proportion of linear bifunctional alcohols, for example, ethylene glycol, butane diol, hexane diol, preferably butane diol, and/or cycloaliphatic bifunctional alcohols, for example, cyclohexane dimethanol and, in addition, optionally small amounts of higher-functionality alcohols, for example, 1,2,3-propane triol or neopentyl glycol, and of linear bifunctional acids, for WW 5469-Foreign example, succinic acid or adipic acid, and/or optionally cycloaliphatic bifunctional acids, for example, cyclohexane dicarboxylic acid and, in addition, optionally small amounts of higher-functionality acids, for example trimellitic acid, or s G) an ester proportion of acid- and alcohol-functionalised building blocks, for example, hydroxybutyric acid or hydroxyvaleric acid or derivatives thereof, for example, ~-caprolactone, or a mixture or a copolymer of F) and G) and H) a carbonate proportion which is prepared from aromatic bifunctional phenols, preferably bisphenol A and carbonate donors, for example, phosgene, wherein the ester proportion F) and/or G) is at least 70 wt.% based on the sum of F), G) and H).
Aliphatic polyester amides of 20 I) an ester proportion of linear and/or cycloaliphatic bifunctional alcohols, for example, ethylene glycol, hexane diol or butane diol, preferably butane diol, or cyclohexane dimethanol and, in addition, optionally small amounts of higher-functionality alcohols, for example, 1,2,3-propane triol or neopentyl glycol, and of linear and/or cycloaliphatic bifunctional acids, for example, succinic acid, adipic acid, cyclohexane dicarboxylic acid, preferably adipic acid and, in addition, optionally small amounts of higher-functionality acids, for example trimellitic acid, or K) an ester proportion of acid- and alcohol-functionalised building blocks, for example, hydroxybutyric acid or hydroxyvaleric acid or derivatives thereof, for example, ~-caprolactone, .. . . . .
WW 5469-Forei~n g or a mixture or a copolymer of I) and K) and L) an amide proportion of linear and/or cycloaliphatic bifunctional and, in S addition, optionally small amounts of higher-functionality amines, forexample tetramethylene (1i~mine, hexamethylene diamine, isophorone diamine, and of linear and/or cycloaliphatic bifunctional acids and, in addition, optionally small amounts of higher-functionality acids, for example, succinic acid or adipic acid, or M) an amide proportion of acid- and amine-functionalised building blocks, preferably c3-laurinlactam and in particular preference ~-caprolactam, or a mixture of L) and M) as amide proportion, wherein the ester proportion I) and/or K) is at least 30 wt.% based on the sum of I), K), L) and M).
The biodegradable and compostable raw materials according to the invention may be 20 furnished with processing auxiliaries and additives such as, for example, nucleating agents (for example, 1,5-naphthalene disodium sulfonate), stabilisers or lubricants.
The biodegradable copolyesters, polyester urethanes, polyester carbonates and polyester amides have a molecular weight of at least 10,000 g/mole and have a 25 random distribution of the starting materials (monomers) in the polymer.
The biodegradable polymers mentioned are preferably polyester urethanes and polyester carbonates and particularly preferably polyester amides.
30 The invention also provides the use of a certain class of materials of biodegradable and compostable polymers for the plepaldlion of the film, said class of materials WW 5469-Foreign being polyester amide. The film according to the invention may be prepared from a polyester amide or a mixture of various polyester amides.
Suitable flatting agents for layer (1) of the film according to the invention are 5 minerals which are used in the form of powder, as is customary for incorporation in non-biodegradable thermoplastics.
The mineral fillers include, for example and in preference gypsum, wollastonite and in particular preference chalk and kaolin. Natural and synthetic silicas are likewise to 10 be regarded as suitable. Layer silicates are particularly suitable.
The thermoplastic moulding compositions according to the invention for layer (1)contain 1 wt.% to 80 wt.%, preferably 10 wt.% to 60 wt.%, particularly preferably 20 wt.% to 40 wt.% of minerals, preferably of natural origin.
The layer silicate proportion of the matt layer of the film according to the invention should be, in a particularly preferred embodiment, advantageously at least 10 wt.%, so that a marked flatting is obtained and on the other hand it should not exceed 25 wt.%. Surprisingly, no appreciable impairment of the mechanical strength occurs in 20 this case.
The invention also provides a process for the preparation of the reinforced thermoplastic moulding compositions according to the invention, characterised inthat the fillers are intim~tely mixed with the biodegradable polymer, e.g. in a 25 kneader or preferably an extruder.
It is generally advantageous, mainly from an economic angle, if the matt layer accounts for a small proportion of the total layer thickness of the film flatted on one side. Consequently, thickness combinations in which the proportion of the layer 30 flatted with layer silicate is 15 - 40% of the total layer thickness are of particular interest.
WW 5469-Forei~n The addition of the flatting layer silicate is carried out preferably in the form of an additive masterbatch which, in a particularly preferred embodiment, has a weightproportion of layer silicate between 30 and 80 wt.%. A smaller proportion has 5 economic disadvantages whilst a higher proportion of layer silicate in the masterbatch brings about a poor distribution which becomes appale~ll, for example, in undesirable silicate agglomerates. This causes a more uneven rollghn~cs and hence less pleasant tactile properties.
10 Compostable polymers or compostable copolymers with colllpalalively high meltflow indices between 8 and 24 g/10 min, measured in accordance with DIN 53 735 at 190~C and under a test load of 2.16 kg, have proved to be suitable for the preparation of such additive masterbatches. In order to be able to improve the masterbatch homogeneity, further plasticising auxiliaries such as, e.g., waxes, may 15 optionally be contained. To prevent thermal damage of the polymer component of the masterbatch, the latter are usually furnished with stabilisers.
In a preferred embodiment, individual or all layers of the multi-layer-film according to the invention may be modified by the further addition of processing aids, fillers, 20 colorants and stabilisers. Colorants permit the production of plasters for special fields of application.
In one of these selected embodiments, at least one of the layers contains coloured pigments. Beige-coloured film is popular if wound and wound cover are not to be 25 openly visible. Bright colourings and printing applications are used in many cases in children's plasters. Further additives such as silicates and waxes modify the application properties, particularly the surface slip behaviour. Stabilisers make it possible to keep the films according to the invention over a lengthy period and to prevent damage during processing. The common additives for plastics are described 30 by Gachter and Muller in: Handbuch der Kunststoff Additive, Hanser Verlag, Munich 1983.
WVV 5469-Foreign The invention also provides processes for the plepalalion of the film according to the mventlon.
5 Said processes are characterised in that the biodegradable and compostable material(s) are initially broken down by the effect of heat and shear, the melt streams are placed one over the other in a die and discharged and cooled until solidification.
This may be carried out by conventional processes of flat or blown film extrusion.
10 Said processes are described, for example, by Michaeli in: Extrusionswerkzeuge fur Kunststoffe und Kautschuk, Carl Hanser Verlag, Munich 1991. Further information is given in Handbuch der Kunststoff Extrusionstechnik, published by Hensen, Knappe and Potente, Carl Hanser Verlag, Munich 1989.
15 The winding of the film, and also a further treatment by heating and/or orientation and/or a surface treatment on one or both sides may take place immediately afterwards.
With regard to their later use, the films according to the invention may be modified 20 in terms of their surface properties by a surface treatment process. Corona, plasma or fluorine and flame treatments are particularly suitable for this purpose. Such processes were described in detail, for example, by Dorn and Wahono in Maschinenmarkt 96 (1990) 34-39 or Milker and Moller in Kunststoffe 82 (1992) 978-981. A preferred process is the corona treatment.
In the corona treatment, the procedure is advantageously such that the film is passed between two conducting elements acting as electrodes, whereby such a high current -usually alternating current of about 10 kV with a frequency of 10 kHz - is applied between the electrodes that corona discharges can take place. As a result of these 30 discharges, the air along the film surface is ionised so that reactions take place on the film surface during which polar groups are produced in comparison with the WW 5469-Foreign polymer matrix. The treatment intensities required for the pretreatment of the films according to the invention lie within the usual bounds, treatment intensities that yield surface tensions from 38 to 50 mN/m being preferred.
5 The films according to the invention may be pretreated on one or both sides. The purpose of such treatments is to improve the surfaces in terms of their properties of adhesion to the printing and/or coating materials. In the case of plasters, conventional printing applications are, for example, brightly coloured ~nim~l~ or articles which are printed preferably on the matter side of children's plasters. The 10 coating with pressure-sensitive adhesives is generally a conventional process with plasters, and takes place preferably on the smoother side of the film.
In the case of orientation, heating in the case of partially crystalline materials takes place to temperatures below the crystalline melting point and in the case of 15 amorphous materials to above the glass transition temperature, followed by one or more biaxial orientation operations. After the orientation stage(s), a fixing of the film may optionally be carried out in each case. After the orientation processes and the possibly predominant fixing stages, the film thus manufactured may optionally be surface-treated in line. The treatment may be carried out with a corona, flame, 20 plasma or an oxidative substance or mixture of substances such that an increase in the surface tension on the film is obtained.
The invention also provides a process for orienting the film. Biaxial orientation may be carried out in a simultaneous stretching process or in a two-stage sequential25 process wherein both longitudinal followed by transverse stretching and transverse followed by longitudinal stretching may take place, or in a three-stage sequential process wherein both longitudinal followed by transverse and finally longitudinal stretching and transverse followed by longitudinal and finally transverse stretching may take place, or in a four-stage sequential process wherein both longitudinal 30 followed by transverse followed by longitudinal and finally transverse stretching and WW 5469-Foreign transverse followed by longitudinal followed by transverse and finally longitudinal stretching may take place.
Each individual orientation may optionally be followed by a fixing of the film. The individual orientation in a longitudinal and transverse direction may take place in one or more stages in this case.
In a preferred form of the film according to the invention, biaxial orientation is characterised in that it is a sequential process that starts with longitudinal stretching.
In an even more preferred form of the film according to the invention, biaxial orientation is characterised in that the total stretch ratio in the longitudinal direction is 1: 1.5 to 1: 10 and the total stretch ratio in the transverse direction is 1: 2 to 1:
20.
In an even more preferred form of the film according to the invention, biaxial orientation is characterised in that the total stretch ratio in the longitudinal direction is 1: 2.8 to 1: 8 and the total stretch 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, said film has a thickness of < 500 llm.
A particular embodiment of the films according to the invention is characterised in that the film has a total thickness between at least 30 ~Lm and at most 200 ~m. Films with a thickness of at least 50 ~lm and at most 100 ~m are particularly suitable.
The invention also provides the use of the film according to the invention. A suitable application is the use of said film as a solo film in pretreated or non-pretreated and in printed or unprinted form for coating with pressure-sensitive adhesives. The film coated in this way is suitable, for example, as a label or adhesive strip. A further WW 5469-Foreign fini~hing stage is the provision of wound coverings or active substance release functions which are customary with plasters.
In order to improve printing adhesion or anchoring of the adhesive, the film surface 5 may be pretreated during preparation and/or afterwards during further processing with a corona, flame, plasma or another oxidative substance or mixture of substances such that an increase in the surface tension is obtained.
In a particularly preferred use of said film according to the invention, only 10 substances which are biodegradable and compostable are used to prepare a plaster structure, so that the entire composite is likewise biodegradable and compostable.
The invention also provides the use of the film according to the invention as starting material for the ~repaldlion of an adhesive tape or plaster with very high water15 vapour permeability, said film being pierced with a cold or heated spiked roller. The intended use of said film is wound covering and protective film in the hygiene sector.
The invention is explained in even more detail below on the basis of examples and 20 comparative examples, and a comparison of the examples with one another and with the comparative examples is made on the basis of the summary of relevant properties shown in Table 1.
WW 5469-Fore;~n Example 1 Within the context of the first example a two-layer film was produced by coextrusion on a blown film unit. The extruders used for melting were operated with temperature programmes of 130 - 145~C, the temperature of the blown film die being 145~C.
The formed film had a layer thickness sequence of 20 ~m, 60 ~lm. In view of the inaccuracy of a thickness determined by mechanical sc~nning due to the roughening effect of the addition of layer silicate according to the invention, the stated thicknesses are nominal layer thicknesses which were determined by calculation on the assumption of a smooth surface of what was actually the rough, matt side. On the basis of the densities of the raw materials and the averaged densities of the raw material mixtures, these nominal layer thicknesses and the total nominal layer thickness can be calculated by adding the values obtained for the respective layers.
The non-matt 60 llm thick layer which formed the outer layer (1) of the film bubble during film production was produced from a compostable polyester amide. The polyester amide used was composed of the building blocks butane diol, adipic acid and caprolactam. It had a melt viscosity of 250 Pas at 190~C (measured in accordance with DIN 54811-B) and a melting point of 125~C, measured in accordance with ISO 3146/C2. The density of the polyester amide was 1.07 g/cm3, measured in accordance with ISO 1183.
The outer layer formed from the polyester amide resin with the addition of lubricants underwent a corona treatment after film production, and a surface tension of 35 mN/m was obtained.
The 20 ~m thick inner layer (2) of the film was produced from a mixture composedof 70 wt.% of the polyester amide resin used for the 60 ~m thick layer and 30 wt.%
of a layer silicate masterbatch. Said masterbatch had a talc proportion of 50 wt.%.
WW 5469-Foreign The size of the talc particles was less than 22 ~lm. The melt temperature measured after the die exit was 152~C.
Example 2 A two-layer film structure with a total thickness of 51 ~Lm of biodegradable polyester amide with a melt viscosity of 250 Pas at 190~C (measured in accordance with DIN54 811 - B) and a melting point of 125 ~C measured in accordance with ISO
3146/C2 was biaxially oriented under the following process parameters. The maximum extrusion temperature was 205~C.
Accordingly, the extruder heating zones were heated to a maximum of 182~C and the die to a maximum of 205~C. The melt was cooled as a two-layer flat film on chill rolls at roll temperatures of 20~C. A rigid thick film was obtained which was heated to orientation temperature in the next process stage by means of heating rolls with temperatures of 65~C. The smooth layer (1) was composed of polyester amide with the addition of lubricants. It had a thickness of 39 ~m.
The matt layer (1) with a thickness of 12 llm was prepared from a mixture composed of 80 wt.% of the polyester amide resin used for the 39 llm thick layer and 20 wt.%
of a silica masterbatch. The masterbatch had a silica proportion of 40 wt.%. The size of the silica particles was < 15 llm.
The actual stretching rolls were operated at a temperature of 70~C. Initially, the flat film was stretched longitudinally in two stages firstly by the ratio 1: 1.5 and then by the ratio 1: 2.5. A total stretch ratio of 1: 3.75 was thus obtained in the longitudinal direction. The post-heating rolls over which the film then passed had a temperature of 85~C. The pre-heating zones of the transverse stretching oven were heated to 100~C. The temperature in the actual transverse stretching part was 95~C. Here the film was stretched in the transverse direction by the ratio of 1: 5 . By calculation, a surface stretch ratio of 1: 18.75 was thus obtained. After transverse stretching, the ~W 5469-Forei~n film was fixed at a temperature of 105~C. The production speed at the outlet of transverse stretching was 32.0 m/min.
Comparative example A
A single-layer film with a thickness of 100 ~lm was formed with a blown film die as in Example 1. The polyester amide resin used was furnished with lubricants.
Comparative example B
A single-layer flat film of polyester amide was oriented as in Example 2. The polyester amide resin was furnished with lubricants. The film thickness was 46 llm.
The following physical properties and compostability were measured as follows onthe samples produced.
Mechanical properties:
The mechanical variables ultimate tensile strength and elongation at break were determined on the samples both in the longitudinal and in the transverse direction according to DIN 53 455. The E-modulus in the longitudinal and transverse direction was determined according to DIN 53 457. The thickness of the individual samples was determined according to D~N 53 370.
Optical properties:
The optical properties determined on the films were the surface gloss according to 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 specification of the D~N draft standard DIN 54 900 part 3 of 1996. On the basis of the test results, the WW 5469-Forei~n classification of the film samples in the apl)ropliate class is carried out according to the DIN recommendations.
The results of the tests on the samples from Example 1 and 2 and comparative 5 examples I and 2 are given in Table 1.
Table 1 Example Example Comparative Comparative 2 example 1 example2 Mechanical properties Thickness [~m] 80 51 100 46 E-modulus long. [MPa] 280 255 270 226 E-modulus transv. [MPa] 323 305 350 292 Ultimate tensile 54 92 SS 90 strength long. [MPa]
Ultimate tensile 42 111 40 109 strength transv. [MPa]
Elongation at break 390 186 412 224 long. [%]
Elongation at break 630 98 654 111 transv. [%]
Optical properties Gloss [GU], matter side 0.8 S 3.1 105 Gloss [GU], smoother side 3.0 78 3.2 116 Compostability yes yes yes yes Biodegradability All the films according to the invention given in the examples have reduced gloss 10 compared with the films examined within the context of the comparative examples.
Claims (9)
1. A compostable film having at least two layers, characterised in that the filmaccording to the invention has a low tendency to curl and has on one side gloss values of < 10, measured in accordance with DIN 67 530 at an angle of 20°, wherein the outer layer of the film having the lower gloss values contains a proportion from 1 to 80% of substantially uniformly distributed filler, the average particle size of which is < 22 µm and, as matrix materials of the individual layers of the polymer-resin layer structure, polymers from the group comprising I. aliphatic and partly aromatic polyesters II. aliphatic polyester urethanes III. aliphatic-aromatic polyester carbonates IV. aliphatic polyester amides.
2. A film according to claim 1, characterised in that the biodegradable polymer or polymers are copolyesters of the groups comprising I. aliphatic and partly aromatic polyesters of A) linear bifunctional alcohols and/or optionally cycloaliphatic bifunctional alcohols and, in addition, optionally small amounts of higher-functionality alcohols and of linear bifunctional acids and/or optionally cycloaliphatic bifunctional acids and/or optionally aromatic bifunctional acids and, in addition, optionally small amounts of higher-functionality acids, or B) acid- or alcohol-functionalised building blocks or derivatives thereof, or a mixture or a copolymer of A) and B), wherein the aromatic acids account for a proportion of not more than 50 wt.%, based on all the acids, or of II. aliphatic polyester urethanes of C) an ester proportion of linear bifunctional alcohols and/or optionally cycloaliphatic bifunctional alcohols and, in addition, optionally small amounts of higher-functionality alcohols and of linear bifunctional acids and/or optionally cycloaliphatic and/or aromatic bifunctional acids and, in addition, optionally small amounts of higher-functionality acids or D) an ester proportion of acid- and alcohol-functionalised building blocks or derivatives thereof, or a mixture or a copolymer of C) and D), and E) the reaction product of C) and/or D) with aliphatic and/or cycloaliphatic bifunctional isocyanates and, in addition, optionally higher-functionality isocyanates and optionally, in addition, with linear and/or cycloaliphatic bifunctional and/or higher-functionality alcohols, wherein the ester proportion C) and/or D) is at least 75 wt.%, based on the sum of C), D) and E), or of III. aliphatic-aromatic polyester carbonates of F) an ester proportion of linear bifunctional alcohols and/or cycloaliphatic bifunctional alcohols and, in addition, optionally small amounts of higher-functionality alcohols and of linear bifunctional acids and/or optionally cycloaliphatic bifunctional acids and, in addition, optionally small amounts of higher-functionality acids, or G) an ester proportion of acid- and alcohol-functionalised building blocks or derivatives thereof, or a mixture or a copolymer of F) and G) and H) a carbonate proportion which is produced from aromatic bifunctional phenols and carbonate donors, wherein the ester proportion F) and/or G) is at least 70 wt.% based on the sum of F), G) and H), or of IV. aliphatic polyester amides of I) an ester proportion of linear and/or cycloaliphatic bifunctional alcohols and, in addition, optionally small amounts of higher-functionality alcohols and of linear and/or cycloaliphatic bifunctional acids and, in addition, optionally small amounts of higher-functionality acids, or K) an ester proportion of acid- and alcohol-functionalised building blocks or derivatives thereof, or a mixture or a copolymer of I) and K) and L) an amide proportion of linear and/or cycloaliphatic bifunctional and, in addition, optionally small amounts of higher-functionality amines and of linear and/or cycloaliphatic bifunctional and, in addition, optionally small amounts of higher-functionality acids, or M) an amide proportion of acid- and amine-functionalised building blocks, or a mixture of L) and M) as amide proportion, wherein the ester proportion I) and/or K) is at least 30 wt.% based on the sum of I), K), L) and M).
3. A film according to one of claims 1 and/or 2, characterised in that silicas and/or silicates are used as filler.
4. A film according to claims 1 and/or 2, characterised in that the individual layers of the film may contain further processing auxiliaries, the preferred additives including silicates, waxes and colorants.
5. A film according to at least one of the preceding claims, characterised in that the biodegradable and compostable polymer or polymers are polyester amides.
6. A process for the preparation of a film according to claims 1 - 5, characterised in that it is prepared by extrusion.
7. A process according to claim 6, characterised in that the film undergoes biaxial orientation during preparation.
8. A process according to claim 7, characterised in that the total stretch ratio in the longitudinal direction is 1:1.5 to 1:10 and the total stretch ratio in the transverse direction is 1:2 to 1:20.
9. The use of the film according to claims 1 to 5, characterised in that it is used as solo film in pretreated or non-pretreated and in printed or unprinted form provided with additional adhesive as supporting film for labels, adhesive tapes and/or plasters.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19630231.5 | 1996-07-26 | ||
| DE19630231A DE19630231A1 (en) | 1996-07-26 | 1996-07-26 | Compostable carrier web |
| PCT/EP1997/003745 WO1998004412A1 (en) | 1996-07-26 | 1997-07-14 | Compostable backing foil |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2262000A1 true CA2262000A1 (en) | 1998-02-05 |
Family
ID=7800952
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002262000A Abandoned CA2262000A1 (en) | 1996-07-26 | 1997-07-14 | Compostable backing foil |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP0914250A1 (en) |
| JP (1) | JP2000516545A (en) |
| KR (1) | KR20000029557A (en) |
| CN (1) | CN1226203A (en) |
| AU (1) | AU718448B2 (en) |
| BR (1) | BR9710571A (en) |
| CA (1) | CA2262000A1 (en) |
| DE (1) | DE19630231A1 (en) |
| IL (1) | IL128074A0 (en) |
| WO (1) | WO1998004412A1 (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19811225A1 (en) * | 1998-03-18 | 1999-09-30 | Wolff Walsrode Ag | Improving the hydrolysis stability of films made from biodegradable polymers and processes for producing such films |
| DE19811773A1 (en) * | 1998-03-18 | 1999-09-23 | Wolff Walsrode Ag | Opaque, biodegradable and compostable film for packaging fruit and vegetables and for covering plants or greenhouses |
| DE19811226A1 (en) * | 1998-03-18 | 1999-09-30 | Wolff Walsrode Ag | Multi-layer, thermoplastic films made of polyester amide and process for their production |
| US6372339B1 (en) | 1998-10-16 | 2002-04-16 | Nitto Denko Corporation | Substrate film for adhesive sheet and adhesive sheet using the same |
| DE19912996A1 (en) * | 1999-03-23 | 2000-09-28 | Wolff Walsrode Ag | Biodegradable agricultural films |
| DE19921885A1 (en) * | 1999-05-12 | 2000-11-16 | Bayer Ag | Dispersion or solution for production of removable surface film, e.g. for protecting objects during transport, contains aliphatic polyester, polyester-urethane, -amide or -carbonate and micron-sized filler |
| WO2001000730A1 (en) * | 1999-06-25 | 2001-01-04 | Mitsui Chemicals, Inc. | Aliphatic polyester composition for masterbatch and process for producing aliphatic polyester film with the composition |
| DE19950295A1 (en) * | 1999-10-19 | 2001-04-26 | Beiersdorf Ag | Foil-based dressing material with imprint |
| DE19954405A1 (en) * | 1999-11-12 | 2001-05-17 | Wolff Walsrode Ag | Multi-layer, biodegradable, thermoplastic films and processes for their production and their use as packaging material and in cosmetic and hygiene articles |
| ITVI20100216A1 (en) * | 2010-07-30 | 2012-01-31 | Sacme S P A | BIODEGRADABLE COMPOUND ON POLYESTER CARRIER APPLIED TO A BIOPOLYMER |
| DE102015109642A1 (en) * | 2015-06-17 | 2016-12-22 | Leonhard Kurz Stiftung & Co. Kg | Foil, method of decorating an object and article |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3242658B2 (en) * | 1992-06-26 | 2001-12-25 | ザ、プロクター、エンド、ギャンブル、カンパニー | Biodegradable liquid-impermeable multilayer film composition |
| JPH073138A (en) * | 1993-06-15 | 1995-01-06 | Uni Charm Corp | Resin composition, porous film obtained therefrom, and production of the same film |
| FI99125C (en) * | 1993-12-31 | 1997-10-10 | Neste Oy | Polylaktidsammansättning |
| CA2158944A1 (en) * | 1994-01-24 | 1995-07-27 | Kozo Kotani | Biodegradable resin composition, film and molding |
| JP3328070B2 (en) * | 1994-06-17 | 2002-09-24 | 株式会社資生堂 | Resin container |
| JPH08283541A (en) * | 1995-04-13 | 1996-10-29 | Showa Denko Kk | Image formation support |
| JPH08290692A (en) * | 1995-04-25 | 1996-11-05 | Toppan Printing Co Ltd | Biodegradable card |
| EP0765911A3 (en) * | 1995-09-26 | 1998-05-20 | Bayer Ag | Reinforced biodegradable plastics |
-
1996
- 1996-07-26 DE DE19630231A patent/DE19630231A1/en not_active Withdrawn
-
1997
- 1997-07-14 IL IL12807497A patent/IL128074A0/en unknown
- 1997-07-14 CN CN97196781A patent/CN1226203A/en active Pending
- 1997-07-14 WO PCT/EP1997/003745 patent/WO1998004412A1/en not_active Application Discontinuation
- 1997-07-14 AU AU36947/97A patent/AU718448B2/en not_active Ceased
- 1997-07-14 BR BR9710571A patent/BR9710571A/en not_active Application Discontinuation
- 1997-07-14 JP JP10508432A patent/JP2000516545A/en active Pending
- 1997-07-14 KR KR1019997000615A patent/KR20000029557A/en not_active Application Discontinuation
- 1997-07-14 EP EP97933673A patent/EP0914250A1/en not_active Withdrawn
- 1997-07-14 CA CA002262000A patent/CA2262000A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| KR20000029557A (en) | 2000-05-25 |
| BR9710571A (en) | 1999-08-17 |
| AU3694797A (en) | 1998-02-20 |
| IL128074A0 (en) | 1999-11-30 |
| EP0914250A1 (en) | 1999-05-12 |
| CN1226203A (en) | 1999-08-18 |
| AU718448B2 (en) | 2000-04-13 |
| JP2000516545A (en) | 2000-12-12 |
| DE19630231A1 (en) | 1998-01-29 |
| WO1998004412A1 (en) | 1998-02-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |