PULP FOR PAPER, BOARD OR CARD AND THE PROVISION AND USE THEREOF

Abstract

Paper, board and/or card and a fibrous mixture for producing the same are disclosed. The mixture includes a fraction of fibrous material got from broad-leaved plants and a fraction of pulp. The fibrous broad-leaved plant material is preferably produced from a pomace, especially a food production pomace, and is used to produce packaging for the food from which the pomace was obtained.

Claims

1. A fibre material mixture for the production of paper, paperboard and/or cardboard, which contains a fraction of a herb fibre material retrieved from a herb pomace and a fraction of pulp.

2. The fibre material mixture according to claim 1, wherein the fraction of herb fibre material is 5% to 70%, preferably 30% to 60%, and particularly preferably 40% to 50%, of a total weight of fibre materials in the mixture.

3. The fibre material mixture according to claim 1, wherein the herb fibre material consists of a mixture of fibre materials retrieved from different herb species.

4. The fibre material mixture according to claim 1, wherein herbs for retrieval of the herb fibre material are selected from the herb species burnet, speedwell, sage, elderflower, thyme, ribwort, lady's mantle, primrose, mallow, horehound, peppermint, yarrow, marshmallow, verbena, hops, chamomile, poppy, lavender, orange blossom, orange leaves, rose blossom, vervain, apple mint, nettle, bergamot mint, ginger mint, lime mint, stevia and/or subspecies thereof.

5. The fibre material mixture according to claim 1, wherein the mixture contains a weight fraction of 30% to 95% of pulp.

6. The fibre material mixture according to claim 1, wherein the pulp fraction is composed of a larger part of short-fibre pulp and a smaller part of long-fibre pulp.

7. The fibre material mixture according to claim 1, wherein the mixture contains a fraction of fibre material retrieved from grass, wherein a weight fraction of grass fibre material corresponds to half of the weight fraction of herb fibre material to the double of the weight fraction of herb fibre material.

8. The fibre material mixture according to claim 1, wherein it has a weight fraction of 20%-30% of herb fibre material (preferably 25%), a weight fraction of 20%-30% of grass fibre material (preferably 25%) and a weight fraction of at least 40% of pulp (preferably 50%), with all weight fractions together giving a total weight of fibre materials in the mixture of 100%.

9. A method for providing a fibre material for the production of paper, paperboard and/or cardboard, in which herbs are used as fibre raw material, which are mechanically and/or chemically decomposed and processed into a pomace for retrieval of the fibre material.

10. The method according to claim 9, wherein herb cellulose remains in the herb pomace and other herb components are extracted.

11. The method according to claim 9, wherein the herbs are selected from the herb species burnet, speedwell, sage, elderflower, thyme, ribwort, lady's mantle, primrose, mallow, horehound, peppermint, yarrow, marshmallow, verbena, hops, chamomile, poppy, lavender, orange blossom, orange leaves, rose blossom, vervain, apple mint, nettle, bergamot mint, ginger mint, lime mint, stevia and/or subspecies thereof.

12. The method according to claim 9, wherein a herb pomace, produced from the herbs, is dried at a temperature between 50° C. to 140° C. (preferably 125° C.) (Residual moisture of <10%) (drum dryer).

13. The method according to claim 9, wherein the herb pomace is dried and subsequently milled in a first milling process to a fibre length of 5 mm to 10 mm (preferably at most 8 mm).

14. The method according to claim 13, wherein the dried and milled herb pomace is subjected to a second milling process in a press.

15. A method for producing paper, paperboard and/or cardboard, in which the fibre material mixture according to claim 1 and/or a herb fibre material in which herbs are used as fibre raw material, which are mechanically and/or chemically decomposed and processed into a pomace for retrieval of the fibre material is used.

16. The method according to claim 15, wherein the fibre material mixture is whipped with water to form a suspension and the fibre materials in the suspension are milled with a freeness of 2500 to 3500 (preferably 3000).

17. Paper, paperboard or cardboard produced from the fibre material mixture according to claim 1 and/or from a herb fibre material in which herbs are used as fibre raw material, which are mechanically and/or chemically decomposed and processed into a pomace for retrieval of the fibre material.

18. A packaging for a food, which is at least partially made of paper, paperboard and/or cardboard, wherein the paper, the paperboard and/or the cardboard has a fraction of fibre material, which is retrieved from pomace originating from the production of the food.

19. The packaging according to claim 18, wherein the food is made at least partially from herbs and the fraction of fibre material is provided from a herb pomace, the herb pomace originating from the production of the herb food.

20. The packaging according to claim 19, wherein the fraction of fibre material is provided by a method in which herbs are used as fibre raw material, which are mechanically and/or chemically decomposed and processed into a pomace for retrieval of the fibre material.

Description

[0036] The invention is explained in more detail by means of examples, tests and figures. These are only intended to illustrate the concept of the invention and are not to be interpreted as restrictive. They show:

[0037] FIG. 1: Table of test results for four selected tests to produce paper, paperboard and/or cardboard in connection with herb fibre materials according to the present invention, and

[0038] FIG. 2: Diagram of a process sequence for drying during a process according to the invention for the provision of a herb fibre material.

[0039] For the production of food packaging from paper, paperboard and/or cardboard according to the present invention, a fibre material mixture is used which contains a fraction of fibre material retrieved from herbs and a fraction of pulp. From this fibre material mixture paper, paperboard and/or cardboard are made for food packaging.

[0040] The pulp used is e.g. retrieved by a sulphite or a sulphate process. Both processes dissolve lignin from wood fibres through chemical reactions during a cooking process lasting several hours, whereby the fibres remain undamaged and in full length. As a result, pulp has a higher basic whiteness and a higher tensile strength compared to wood pulp. To further increase the whiteness of pulp, it can be bleached with oxygen, hydrogen peroxide or sodium chloride after the decomposition process.

[0041] The fraction of fibre material retrieved from herbs is advantageously retrieved from a pomace that is produced during the production of food such as candies, tea extract, spices, etc. For the production of the pomace, the herbs are pressed, milled or grated to release their ingredients. Due to the extraction of the herb ingredients, only the herb cellulose and thus the component important for fibre material production remain. When producing fibre material packaging for the food from which the herb pomace originates, upcycling can be achieved, which reduces the need for fresh fibre material in the packaging production.

[0042] To provide herb fibre material from pomace, two tests were carried out in which herb pomace was obtained from a food producer and herb fibre material was retrieved therefrom. The pomace is preferably removed directly behind a system for extracting the herb ingredients. In this way, contamination of the pomace can be prevented and, if necessary, the necessary hygiene standards can be met.

[0043] In a first test, a mixed pomace was used, which was retrieved from a mixture of the following herb species: burnet, speedwell, sage, elderflower, thyme, ribwort, lady's mantle, primrose, mallow, horehound, peppermint, yarrow, lime blossom, lemon balm, orange mint, hyssop and marshmallow.

[0044] To dry the mixed pomace, a drying cabinet with a temperature of 40° C. and activated fan was used. The herbs were divided into dry baskets. To avoid moisture pockets, a low layer height is used in the dry baskets. Furthermore, the herb material is turned from time to time. After about 24 hours, the dry matter content was about 90%. A higher temperature is recommended to reduce the drying time. In a second test, a tea pulp was used that was retrieved from a mixture of the following herb species: burnet, speedwell, sage, elderflower, thyme, ribwort, lady's mantle, primrose, mallow, horehound, peppermint, yarrow, lime blossom, lemon balm, hyssop and marshmallow. A temperature of 60° C. was used. This enabled the drying time to be shortened to less than 18 hours. In addition, this test did not result in the formation of moisture pockets, which suggests more homogeneous drying. In this test, too, a dry content of a nearly 92% was achieved. Furthermore, the second drying test clearly showed that it is important for a later, industrial solution to ensure a low layer thickness or a thorough mixing of the pomace. Only in this way the formation of moisture pockets and the associated long drying time can be prevented.

[0045] With the herb fibre materials thus retrieved, laboratory tests were carried out to produce a cardboard for packaging with a grammage between 250 g/m.sup.2 and 260 g/m.sup.2, which are based on different fibre material mixtures. The laboratory tests are intended to serve as the basis for industrial production of such a packaging cardboard.

[0046] In the first tests, the workability and the technical effects of the individual pomace were examined. The fibre material mixtures with herb fibre fraction listed below were used for the test samples.

TABLE-US-00001 Type of herb Herb frac- Grass Pulp long Pulp short Wood pulp pomace tion fraction fraction fraction fraction Mixed pomace 50%  0% 20% 30% 0% Mixed pomace 25% 25% 20% 30% 0% Tea pomace 50%  0% 20% 30% 0% Tea pomace 25% 25% 20% 30% 0%

[0047] Freeness of 0, 500, 1000 and 3000 revolutions were used for each of the fibre material mixtures.

[0048] In second tests, it was tested to replace—because of its origin—ecologically “bad”, short-fibre pulp, with wood pulp or the like. Thereby, exclusively the freeness of 3000 revolutions was used since this had proven to be optimal in the first tests. The fibre material mixtures listed below were selected for the test samples.

TABLE-US-00002 Type of herb Herb frac- Grass Pulp long Pulp short Wood pulp pomace tion fraction fraction fraction fraction Mix + tea 30% 25% 25%  0% 20% Mix + tea 30% 25% 30%  0% 15% Mix + tea 30% 20% 25%  0% 25% Mix + tea 45% 25% 20%  0% 10% Mix + tea 25% 20% 20% 20% 15% Mix + tea 30% 20% 15% 25% 10% Mix + tea 60% 20%  0%  0% 20% Mix + tea 40% 20% 40%  0%  0%

[0049] In third tests, a pulp board was made from a fibre material mixture without herb fibres in order to get a direct, technical comparison with a non-machine-made pulp board. The fibre material mixtures listed below were chosen for the test samples and a freeness of 3000 revolutions was chosen.

TABLE-US-00003 Type of herb Herb frac- Grass Pulp long Pulp short Wood pulp pomace tion fraction fraction fraction fraction — 0%  0% 40% 60% 0% — 0% 50% 20% 30% 0%

[0050] After the individual fractions of fibre raw materials for the fibre material mixtures have been weighed, they are whipped in water in a whipping device for about 15 minutes and mixed. The fibres dissolve in the water and form a suspension.

[0051] After the fibres have been mixed, they are mechanically separated from the water via a suction filter (Buchner funnel), such that a fibre cake is formed. This is necessary to enable milling under standardised conditions. The fibres are milled by a PFI mill, which mills according to DIN EN 25264-2, by a defined number of mill wheel revolutions (freeness number=number of revolutions). To carry out the milling, the fibre cake separated from the water is brought to a defined 300 g by adding water. The resulting fibre mass is then evenly distributed in the milling chamber and the milling process is started. After the defined milling revolutions have completed, the milled material is poured into a distribution vessel and filled with water. 10 ml of water per gram of surface weight of the later sheet are required in the distribution vessel. This results in the final fibre suspensions with which the tests for sheet formation with the fibre material mixtures listed above can be carried out.

[0052] The laboratory-sized sheet formation for these tests takes place in two main steps, the sheet formation and the drying. The sheet formation is also divided into several process sections, which should guarantee a comparable and reproducible sheet quality.

[0053] To start, a container of a sheet former is filled with water. The prepared final fibre suspension is added to the water. In order to achieve a homogeneous fibre distribution in the resulting suspension, air is supplied in the form of aeration. After the aeration has been stopped, the suspension is left to rest. Subsequently, the water is removed from the suspension and the fibres remain on a sieve in the sheet former. A sheet that forms in the process is knocked off the screen after coating, preferably with a release paper. After the sheet has been produced by the sheet former, it is present as a thin fibre layer on the release paper. Only after a drying process, for example in a steam-heated vacuum press, is the finished, the finished, dry sheet of paper, paperboard or cardboard is removed from the release paper.

[0054] The sheets produced with the laboratory tests were examined for their quality. Measurements were made for the surface weight, the thickness, the specific volume, the bursting pressure, the bending resistance and the bending stiffness. The measurements were carried out according to the usual procedures. For the determination of tear length/strength and flexural strength, the specifications of the ISO 1924-2 and ISO 2493 standards were complied with. Before starting the measurements, it was ensured that the samples are adequately air-conditioned in the standard climate. This provides reproducible and correct results. Measurements were made as follows.

[0055] Surface weight: The measurement of the surface weight was carried out by placing the sheet in a tared balance and automatically calculating the measured value. After completing the measurements, the surface weight could be read from the display of the balance in g/m.sup.2.

[0056] Thickness: The measurement of the thickness was carried out on a cyclic thickness measuring device which outputs the measured value in micrometres. Five measurements per sheet were carried out at different points (edge, centre, etc.). From these measurements, the average value was subsequently calculated. Herewith, the spec. volume can be calculated by dividing it with the surface weight determined in each case.

[0057] Tear length: In order to be able to measure the tear length, a profile had to be created for each sheet beforehand, in which the previously determined values of surface weight and thickness were entered. This allows the measuring device to automatically calculate the tear length of the respective sheet. After a reference run, test strips were inserted and automatically fixed. One of the fixing clamping jaws is located on a fixed part of the measuring device, another sits on a movable slide, which now moves linearly away from the fixed clamping jaw. This tears the test strip apart while a dynamometer determines the required tensile force.

[0058] Burst pressure: With the measurement of the burst pressure, the sample is stretched over a round membrane with a pneumatic hold-down device. Subsequently, the membrane is filled with glycerine, which causes it to expand and penetrate the sheet to be measured. If the sheet tears due to excessive pressure, the membrane returns to its starting position and the next of the three test positions can be clamped. During the measurement, a manometer attached to the membrane determines the hydraulic burst pressure applied in kPa. Subsequently, the three measurement results were then summarised in a calculated average value.

[0059] Flexural rigidity: The measurement of the flexural rigidity was carried out by clamping the sample and bending it 5°, while a free end of the sample contacts a sensor of a load cell. The flexural stiffness is measured in mNm. Subsequently, the cardboard is rotated by a further 25° to a total of 30° of total bending, whereby the bending resistance is determined at the angles 7.5°, 15° and 30° in mN. For further consideration of the measured values, only the bending resistance value at a bending of 15° and the rigidity values at 5° are considered.

[0060] The results of the measurements are summarised in the table in FIG. 1. Surprisingly, the different fibre material mixtures used for the tests showed clear differences in the measured strength values. It can be seen that the mixed pomace achieves higher values in terms of flexural resistance and rigidity compared to the tea pomace. This can be attributed to its higher coarse content in the herb mixture in the form of e.g. burnet root pieces or mint branches. The long, stable fibres of these fractions and the resulting higher average fibre length give the paper a high flexural strength. As a result, the mixed pomace paper with 25% herb content achieved the highest value for flexural rigidity and flexural resistance.

[0061] The tea pomace, which is finer compared to the mixed pomace (smaller average fibre length), produces a lower spec. volume in the paper, whereby its density increases with the same thickness and the fibre-fibre connections are strengthened. As a result, the tea pomace achieves slightly better values in the burst pressure test compared to the mixed pomace.

[0062] It can also be observed that the herb fraction in the paper has an impact on the processability and strength of the paper. Paper with a high herb fraction of 55% could only be knocked off the screen to a limited extent on the sheet former. A herb content of 60% also caused considerable problems during dewatering. This is also the reason for the low, average grammage of these sheets. Furthermore, these sheets achieved less good strength values in bursting and bending tests. This can be attributed to the low fraction of pulp, more precisely the lack of short-fibre pulp. Short-fibre pulp has the main task of filling gaps in paper and thus creating better fibre-fibre cohesion. Long-fibre pulp can only compensate for this to a limited extent, as it primarily provides flexural rigidity and volume in the form of a high average fibre length and a large number of intact fibres. Due to the lack of this pulp fraction, there is no adequate fibre-fibre cohesion on the sheet former, such that the sieved fibre material layer can disintegrate when knocking off.

[0063] The freeness of the final fibre suspension also has an influence on the leaf quality. In all tests of the first series of tests, it can be seen that the strength values, be it burst pressure, tear length, tear resistance or bending resistance, increase due to a refinement of the freeness (high number of revolutions). This can be explained by an increased fibrillation of the fibres, which creates a better fibre-fibre cohesion. During fibrillation, the secondary fibre walls are exposed by squeezing, which leads to an enlargement of the specific fibre surface. As a result, more active binding sites can be formed on the surface of the fibre, which increases the fibre-fibre cohesion.

[0064] The laboratory tests clearly showed good mixtures and freeness for the herb paper production. In general, it was found that milling the fibre mixture is of great importance for the future paper properties. Furthermore, the fraction of short-fibre pulp was an important factor for the processability and strength of the paper. Without the addition of this pulp, the strength values dropped significantly in all strength measurements.

[0065] The fibre material mixture with 25% herb fibres from mixed pomace, 25% grass fibres, 20% long-fibre pulp and 30% short-fibre pulp has proven to be a very good combination of parameters. The grass fibres form an ecologically excellent substitute for pulp in paper. Nevertheless, the paper also contains 20% long-fibre pulp and 30% short-fibre pulp, as these are beneficial for the processability and strength. Due to this combination, the paper achieved the best values for tear length, tear strength and flexural rigidity in the test.

[0066] In the strength values, there was a clear difference between paper purely containing pulp, grass paper and the herb paper. The pulp paper achieves very good fibre cohesion due to its intact, chemically processed fibres. As a result, the pulp paper has very good values in all mechanical properties. Nevertheless, it turned out in the test that the rough sometimes also root-containing (wood-like) herb fibre mixtures also achieve better flexural strength values in herb paper than pure pulp paper.

[0067] All herb paper samples show a distinct green tone, which was produced by the introduction of herbs. The paper becomes optically more interesting but also bumpier with decreasing freeness. In addition, the surface of the herb paper becomes very inhomogeneous at low freeness <1000, which can lead to problems when coating, laminating or printing. With fine freeness >1000 a homogeneous and smooth surface is created, since no large fibres disturb the paper image or the paper surface.

[0068] From an olfactory point of view, the herb paper has a pleasant herb note, which gives it a very natural “touch”.

[0069] For a production of a paper, a paperboard or a cardboard with industrial equipment, the herb fibre material for the fibre material mixture according to the invention was subjected to a suitable preparation. The herb pomace was dried and processed into pellets, as they are usually used in industrial production.

[0070] The drying takes place in a drum dryer. This type of drying ensures permanent mixing of the pomace to be dried. This reliably prevents moisture pockets and minimizes the drying time. The inlet temperature of the herbs in the drum dryer corresponds approximately to the ambient temperature (when testing about 25°). The moisture content of the pomace is around 85-90% when it enters and is reduced to a moisture content of 10-12% within 3 minutes. The herb pomace passes the entire length of the drum three times before it leaves it again at a temperature of approx. 90° C. The drying process itself takes place at a drum end temperature of 125° C. The temperature at the hot air inlet of the drum is between 550° C. and 600° C. The volume flow of this hot air is around 50,000 m.sup.3/h, such that a maximum evaporation capacity of 6500 kg of water per hour is achieved.

[0071] FIG. 2 shows the detailed process sequence and the individual steps in the drying and pelletising system.

[0072] The process sequence can be summarised as follows. First of all, herb pomace 1 is provided. This is subjected to a dosage 2 and then chopped in a chopping step 3 and dried in a drying step 4. Heavy material is separated in a heavy material separation step 5 and fine material is separated in a fine material separation step 6. The resulting product from steps 5 and 6 is milled in a milling step 7 and the milled material is separated in a milling material separation step 8. This is followed by pelleting 9. The pelleted material is cooled in a cooling step 10 and then made available as end product 11.

[0073] During the process, inlet air 12 is supplied in drying step 4 and in cooling step 10. Exhaust air 13 is sucked out of the fine material separation step 6, during pelletising 9 and during the cooling step 10.

[0074] Milling step 7: After the pomace has been dried in drying step 4, it is milled in milling step 7 in a hammer mill. This is important to homogenize the fibre quality and size before pelletising 9, which improves the pellet quality. The freeness is selected via the hole diameter of the milling sieve. A diameter of 8 mm is preferably used, as the downstream pelletising machine is a Kollergang press (=pan mill), whereby a further milling process takes place. If a 5 mm sieve is used, due to the double milling, the fine fractions in the subsequent pellet would be too large, which would result in a significant increase in the burden of the machine wastewater.

[0075] When choosing the drying temperatures in drying step 4, one may approach from the highest temperature (180° C.) to the optimal temperature of 125° C. This prevents clogging due to undried pomace. As a result, the pellets produced contained a residual moisture of <10%, which is optimal for the preservation of the pellets. In addition, the herbs are dried gently enough such that ash formation from burning herb fines is avoided.

[0076] Pelletising 9: The pelletising 9 takes place after the separation of the transport air, which has conveyed here the dried and milled herbs through the pipelines of the system. The pan mill now pelletizes using two wheels the milled herbs in pellets with 8 mm diameter. The resulting forces produce an additional milling effect, which further homogenizes the herb particle sizes. Subsequently, the pellets are cooled using several belt coolers, as they tend to increase in humidity due to condensation as a result of their inherent heat due to drying and pelleting. Once the cooling process is complete, the herb fibre material pellets are available for the paper production.

[0077] For the paper to be produced on the industrial equipment, a fibre material mixture with 15% herbs, 15% grass and 70% pulp content was used. Again, a grammage of 250 g/m.sup.2 was chosen. Although the laboratory tests showed that a fraction of 25% herb fibre material is optimal, a fraction of 15% was chosen for industrial production, since at the time of paper production it was not possible to provide a sufficiently large amount of herb fibre materials. Furthermore, the industrial equipment used has not yet been optimised for production with herbs or grass fibre materials.

[0078] For paper production, 7 t of herb pellets were fed into the production. In the pulper (mixing bucket) of the paper machine, the 7 tons of herb fibres were dissolved and mixed with a further 7 tons of grass fibres and 33 tons of pulp to form a fibre suspension. Subsequently, the fibre suspension was fed into the ongoing paper production process. Herewith, the paper machine goes through several 100 m of start-up waste, in which the desired herb fibre fraction cannot be guaranteed due to mixing with a previously used fibre suspension. After this waste had run through the paper machine, herb paper was constantly produced until the herb fibre suspension was used up.

[0079] After the paper was produced, the next day it was given a transparent starch primer. This is intended to improve the printability of the herb paper.

[0080] This herb paper industrially produced with 15% herb fibre fraction has several special properties. With increasing herb input, the properties such as the smell and the visual appearance can be further changed.

[0081] Visual appearance: The visual appearance of the herb paper appears in a beige, slightly green tone, with many small green and black herb or grass fibres. This gives the herb paper a very natural but also a new, unique or unknown visual appearance.

[0082] Haptics: Haptically, the herb paper is similar to an uncoated kraft or recycled paper.

[0083] Olfactorics: The smell of the herb paper is most intense immediately after production. Here, the paper has a clear herbaceous note.

[0084] For the use as packaging material, it is important that the herb paper does not give off any smell or taste to the packaged food. For this purpose, a Robinson test was carried out, with which the transfer behaviour was checked using small pieces of chocolate. For this purpose, 4 beaker glasses were filled with 3 strips (50 mm×150 mm) of herb paper and small chocolate pieces. Subsequently, the glasses were hermetically sealed and stored. After 5 days, the glasses were opened and the chocolates were evaluated in terms of smell and taste. In all 4 samples, the chocolate acquired no herb/grass taste or odour. It can therefore be rated as unproblematic in terms of smell/taste.

[0085] It follows that a paper, a paperboard or a cardboard with a fraction of fibre material retrieved from herbs is well suited for the packaging of food. The quality characteristics are suitable e.g. for a bag packaging, but also for a box packaging for which a higher flexural rigidity is required. Therefor, a packaging fibre material can be provided from a pomace that is produced in the food production, which has various ecological advantages for the packaging of the food, as explained at the beginning.