EP0545277A1 - Packaging body and use thereof - Google Patents

Abstract

The invention relates to the subject-matter specified in the patent claims. The invention relates to packaging materials, produced from cardboard and paper products, furnished with transparent members, in which the transparent members, after use of the packaging, can be destroyed or dissolved in water and the cellulose/wood pulp portion can be fed to a wastepaper reprocessing plant. The dissolved transparent members can be disposed of by municipal sewage treatment plants without problems, since in place of the hitherto used transparent plastic films, transparent members made of biologically degradable amylose-containing shaped compositions are used. The invention further relates to the use of this packaging body made of at least one transparent member and non transparent member as a recyclable packaging material.

Description

The invention relates to the subject matter specified in the claims. The invention relates in particular to packaging bodies made from cardboard and paper products provided with transparent parts, the transparent parts being able to be destroyed or dissolved in water after use of the packaging and the pulp / wood pulp part being able to be fed to a waste paper processing plant. The loosened transparent parts can be easily disposed of in municipal wastewater treatment plants. Instead of the previously used transparent plastic films, transparent parts made of biodegradable amylose-containing molding compounds can be used. The invention further relates to the use of this packaging body made of at least one transparent part and non-transparent part as a recyclable packaging material.

Cardboard and paper products with transparent parts have had a firm place in the packaging sector for decades and have proven their worth. Representatives of this type of packaging are e.g. Folding boxes with transparent windows, blister packs that are glued to the back of the cardboard, and letter envelopes that have transparent windows for the letter address.

A wide variety of transparent plastic films made of polyvinyl chloride, polyester, polyethylene, polypropylene, polystyrene, cellophane etc. have been used as transparent windows. These previously used transparent synthetic foils are glued into the cardboard and paper sleeves. Mainly water-insoluble synthetic adhesives, for example based on isocyanates, are used for this.

After the packaging materials have been used, they can no longer be reused, since the foils disrupt the process sequences in the waste paper preparation systems by clogging the screens or these process sequences are no longer possible. Manual, upstream separation of the films is far too complex, so that the packaging in question has so far only been disposed of by incineration and landfill can be.

It is foreseeable, however, that in future legislation will only allow packaging materials that can either be recycled or disposed of in an environmentally friendly manner.

Therefore, the problem underlying the invention is to replace the previously used plastic windows in the widespread packaging materials, consisting of paper and cardboard products, provided with transparent windows, with novel, water-destructible or water-soluble, biodegradable windows, which at the reprocessing of the packaging can be removed without any problems, so that the wood pulp / pulp content can in turn be used in waste paper processing plants.

This problem is solved by the features of claims 1 and 14, respectively.

The sub-claims contain advantageous embodiments of the invention.

The invention is based on the finding that, surprisingly, based on amylose-containing molding compositions, water-soluble or water-destructible, biodegradable films can be produced which are suitable for use as transparent windows in cardboard and paper packaging. The film or the transparent part produced from a thermoplastic molding compound by extrusion or coextrusion is also shrinkable and thermoformable and can be used in blister packs.

It is thus possible to produce films from amylose and / or starches containing high amylose, which have an amylose content of at least 50% by weight, in particular from 65 to 95% by weight, and their derivatives, on conventional thermoplastic systems, which can be designed as blown films or flat films. Furthermore, it is also possible to modify the amylose-containing molding compositions with additions of preferably aliphatic polyamides and copolyamides, the transparency (single-phase) of the films being retained. In this case, the films are no longer completely soluble in water, but can be destroyed in water, ie the films are brought into a water-dispersible state in which the amylose-containing fraction dissolves in water and the polymer fraction is dispersed in the form of very fine particles.

According to the invention, a packaging body is thus provided, consisting of at least one transparent part and a non-transparent part, which is recyclable and the transparent part is water-destructible or water-soluble, biodegradable and made from a film made of a thermoplastic, amylose-containing molding compound by extrusion or coextrusion and the non-transparent part made of cardboard or paper is made.

worin

R

ein H-Atom oder ein Alkylrest mit 1 bis 18 C-Atomen

R'

ein Alkylrest mit 1 bis 18 C-Atomen,

R''

eine OH-, OR- oder Polyethergruppe und

a

eine Methylen-, Ethylen- oder Isopropylenrest ist.

This molding composition consists of at least one unmodified and / or at least one modified, preferably chemically modified amylose and / or at least one unmodified and / or at least one modified, preferably chemically modified starch. The starch has an amylose content of at least 50% by weight, in particular 65 to 95% by weight. The chemically modified amylose and / or chemically modified starch has a degree of substitution of 0.01 to 0.5, preferably 0.03 to 0.3 and, in a special embodiment, contains substituents from the group:

wherein

R

an H atom or an alkyl radical having 1 to 18 C atoms

R '

an alkyl radical with 1 to 18 carbon atoms,

R ''

an OH, OR or polyether group and

a

is a methylene, ethylene or isopropylene radical.

In a preferred embodiment, the molding composition can contain additives which are selected from the group consisting of plasticizers, urea, urea derivatives, emulsifiers, lubricants and release agents. The emulsifiers have a hydrophile-lipophile balance (HLB) value from 0 to 20, e.g. Stearates, polyoxyethylene 20 sorbitan monolaurate or polyethylene (20) sorbitan monopalmitate.

In another embodiment, the packaging body according to the invention with a transparent part consists of a water-destructible and biodegradable film made of a molding compound which is a mixture of at least one non-modified and / or at least one modified, preferably chemically modified starch and / or at least one -modified and / or at least one modified, preferably chemically modified amylose and at least one selected, preferably aliphatic polymer with a melting or softening point of 50 to 200 ° C, preferably 60 to 180 ° C. The proportion of the polymer (s) which is (are) preferably selected from the group of polyesters, copolyesters, polyamides, copolyamides, polyolefins, copolyolefins, polyvinyl alcohol, ethylene oxide copolymers, propylene oxide copolymers, vinyl alcohol copolymers, pullulan and gelatin is based 0.1 to 90 parts by weight, preferably 20 to 60 parts by weight, particularly preferably 20 to 40 parts by weight, of the total mixture.

The transparent windows containing amylose or starch can be inserted into the packaging or envelopes according to the invention by means of the corresponding systems for plastic windows, the windows being advantageously glued in with water, starch glue or other water-soluble adhesives.

For the reprocessing of the cardboard boxes / paper packaging according to the invention with the transparent windows these can be easily reprocessed in waste paper processing plants. For this purpose, the used packaging according to the invention is comminuted in a chopping plant, for example a cutting mill, and expediently soaked overnight in water which has an alkaline pH, in particular from 8 to 10.5, particularly preferably from 9.0 to 10.0. Increasing the water temperature to 60 to 80 ° C accelerates and shortens the release process for the transparent films. In a further step, the chips from the cardboard boxes and transparent windows according to the invention can optionally be suspended in water with energy-intensive stirring, preferably in a pulper or fiberizer, and treated intensively mechanically for 10 to 30 minutes, the transparent windows dissolving.

If the transparent windows consist of an amylose and / or starch-polymer mixture, it is advantageous to insert an intermediate step between the first and the further step in which the chips from the cardboard boxes or packaging are treated with enzymes. Bactosol MTN from Sandoz and a wetting agent, for example Sandopan LFW from Sandoz, are suitable for this purpose.

After the treatment steps, the fibers are separated from the water containing amylose and / or starch by sieving, the wastewater being able to be disposed of biologically via a sewage treatment plant and the remaining fibers being able to be reused for paper production.

The invention will now be explained in more detail by the following examples.

I. Production of the amylose-containing molding compositions Starch molding compound I: Example 1a)

According to the process described below, 70 parts by weight of hydroxypropyl corn starch with a degree of substitution of 0.06 and an amylose content of 50% by weight and 15 parts by weight of glycerol, 12.8 parts by weight of sorbitol, 2 parts by weight Parts of urea and 0.2 parts by weight of magnesium stearate a starch molding compound which was then granulated.

Extruder setting data:

• a) Heating zones:
  • (1) room temperature
  • (2) 130 ° C
  • (3) 130 ° C
  • (4) 100 ° C
  • (5) 100 ° C
  • (6) 150 ° C
• b) Pressure: Zone (6) (30-40 bar) 3 x 10⁶ - 4 x 10⁶ Pa
• c) torque: 70%
• d) Vacuum: (-0.4 bar) -4 x 10⁴ Pa.

In the feed area (heating zone 1) of a co-rotating, tightly intermeshing twin-screw extruder with a screw geometry according to FIG. 1 and a screw length-diameter ratio of 41, 70 parts by weight of hydroxypropyl corn starch with a degree of substitution of 0.06 and an amylose content of 50 parts by weight were % and 12.8% by weight of sorbitol were metered in separately at point 7 of FIG. 1, mixed and conveyed simultaneously in the extruder. 0.2% by weight of magnesium stearate was dissolved in 2% by weight of urea at 60 ° C. in 15% by weight of glycerol. This pre-homogenized plasticizer-emulsifier-additive mixture was metered into the extruder (heating zone 2) at point 8 of FIG. 1, then mixed and conveyed simultaneously in the extruder. After disintegrating the starch granules and completely plastifying the starch mixture in the kneading chamber 11 (heating zones 2 and 3) into one homogeneous melt, the starch melt was degassed by applying a negative pressure at point 9 of FIG. 1 (heating zone 4). After passing through the heating zone (5), the homogeneous, thermoplastically processable starch melt in the heating zone (6) was extruded through a nozzle as a strand with little strand expansion (nozzle: 3 mm, strand: 4 mm), cooled and granulated.

Example 1b)

As example 1a), but with a urea fraction of 1 part by weight and a sorbitol fraction of 13.8 parts by weight.

Starch molding compound II:

70 parts by weight of the starch molding composition I from Example 1a) or 1b) were mixed with 30 parts by weight of a selected copolyamide: copolyamide 6 / 6.9 (Grilon CF 62 BSE from Ems-Chemie AG) and into the metering zone of a twin-screw extruder ZSK -30 (Werner Pfleiderer) dosed with 6 heating zones. The speed and the throughput were 100 revolutions ⁻¹ and 8 to 10 kg / hour.

II. Transparent part

Films made from starch molding compound I or II were produced on a state-of-the-art system for blown and flat film production. The films obtained were processed into transparent windows, ie cut to the appropriate size, and then inserted into the envelopes or packaging according to the invention by means of the corresponding systems for plastic windows, the gluing being carried out using water, starch glue or a water-soluble adhesive.

III. Process for disposing of the transparent parts that are used in the packaging according to the invention Example 2:

Reprocessing of mixed packaging waste for tools, screws and nails, consisting of the back of the cardboard and the transparent, thermoformed transparent front, which was made from a flat film of granules with the following composition:
70% propoxylated high amylose corn starch with an amylose content of 85% and a degree of propoxylation of 0.12
15% glycerol
13% sorbitol
2% urea.

5 kg of the packaging waste was soaked overnight in 200 l of water (approx. PH 10, hydrated lime). The entire slurry was then sculpted in a pulper for 20 minutes. After dewatering with a screen press, the resulting fibers could be returned to cardboard production.

Example 3:

This example shows the reprocessing of packaging materials according to the invention for sanitary fittings, made from cardboard boxes and transparent windows, consisting of transparent, cold water-resistant polyamide starch blown films, which was produced from a granulate of the composition below:
40% copolyamide 6 / 6.9 (Grilon XE 3222 from Ems-Chemie)
60% starch molding composition according to the composition from Example 2.

20 kg of packaging waste was pre-shredded into pieces of approx. 2 to 5 cm in length in a chopping plant and placed in a 500 l stirred kettle. Then 300 l of water (pH 6 to 7) was added and subjected to an enzyme treatment for 60 minutes with gentle stirring at 70 ° C. The following additives were added to the fleet for enzyme treatment:
Sandopan LFW 2 ml / l (wetting agent, company Sandoz)
Bactosol MTN 3 ml / l (enzyme, Sandoz).

After this pretreatment, the slurry of the packaging materials was transferred to a fiberizer and treated for 10 minutes. The fibers were then dewatered through a filter screen and fed to the production of cardboard.

Claims (14)

Packaging body consisting of at least one transparent part and a non-transparent part, characterized in that it is recyclable and the transparent part is water-destructible or water-soluble, biodegradable and is made of a film from a thermoplastic, amylose-containing molding compound. Packaging body according to claim 1, characterized in that the non-transparent part consists of cardboard or paper. Packaging body according to claims 1 to 2, characterized in that the film is produced by extrusion or coextrusion. Packaging body according to claim 1, characterized in that the molding composition contains at least one unmodified and / or at least one modified, preferably chemically modified, amylose and / or at least one unmodified and / or at least one modified, preferably chemically modified starch. Packaging body according to claim 4, characterized in that the starch has an amylose content of at least 50% by weight, in particular from 65 to 95% by weight. Packaging body according to claims 4 and 5, characterized in that the chemically modified amylose and / or chemically modified starch substituents selected from the group:

contains what R is an H atom or an alkyl radical with 1 to 18 C atoms R 'is an alkyl radical with 1 to 18 carbon atoms, R '' is an OH, OR or polyether group and a is a methylene, ethylene or isopropylene group. Packaging body according to claims 4 to 6, characterized in that the chemically modified amylose and / or chemically modified starch has a degree of substitution of 0.01 to 0.5, preferably 0.03 to 0.3. Packaging body according to claims 3 to 7, characterized in that the molding composition contains additives selected from the group of plasticizers, urea, urea derivatives, emulsifiers, lubricants and release agents. Packaging body according to claims 3 to 8, characterized in that the molding composition is a mixture of at least one unmodified and / or at least one modified, preferably chemically modified amylose and / or at least one unmodified and / or at least one modified, preferably chemically modified starch and at least one selected, preferably aliphatic polymer with a melting or softening point of 50 to 200 ° C, preferably 60 to 180 ° C. Packaging body according to claim 9, characterized in that the polymer is selected from the group of polyesters, copolyesters, polyamides, copolyamides, polyolefins, copolyolefins, polyvinyl alcohol, ethylene oxide copolymers, propylene oxide copolymers, vinyl alcohol copolymers, pullulan and gelatin. Packaging body according to claims 9 and 10, characterized characterized in that the polymer content is 0.1 to 90 parts by weight, in particular 20 to 60 parts by weight, particularly preferably 20 to 40 parts by weight, based on the total mixture. Packaging body according to claims 1 to 11, characterized in that the film has been subjected to a further shaping, preferably deep drawing or shrinking. Packaging body according to claims 1 to 12, characterized in that it is a letter envelope, a packaging with a cardboard back and transparent transparent front or a cardboard packaging with at least one transparent window. Use of the packaging body from at least one transparent part and a non-transparent part according to one of claims 1 to 13 as a recyclable packaging material.

Images