Grass-Containing Liquid Packaging Board

Abstract

The method according to the invention for producing a grass fibre-containing liquid packaging board has the following steps, specifically: providing a fibre suspension formed from at least a first and second pulp type, wherein the first pulp type is constituted by grass fibres, and the second pulp type is selected from a group of pulps which comprises primary fibres such as chemical pulp, for example sulphate pulp or sulphite pulp, in each case based on long-fibre wood or short-fibre wood, wood pulp, and synthetic fibres or recycled fibres based on one or more recycled paper classifications, mixing and/or swelling the fibres in the pulp suspension under predefined conditions with respect to material density and temperature, grinding the at least two pulp types together in a pulp suspension to a degree of dewatering between 40° SR and 60° SR, adding starch and/or a sizing agent as an additive in the mass, diluting the pulp suspension and producing a board on a paper machine, surface sizing the board using at least one starch-containing suspension, and drying the paper structure to a dry content between 4% and 10%.

Claims

1. A method for producing a grass fibre-containing liquid packaging board having the following steps: providing a fibre suspension formed from at least a first and second pulp type, wherein the first pulp type is constituted by grass fibres, and the second pulp type is selected from a group of pulps which comprises primary fibres based on long-fibre wood or short-fibre wood, wood pulp, and synthetic fibres or recycled fibres based on one or more recycled paper classifications, mixing and/or swelling the fibres in the pulp suspension at a predefined material density and temperature, grinding the at least two pulp types together, in a pulp suspension to a degree of dewatering between 40° SR and 60° SR, adding starch and/or a sizing agent as an additive in the mass, diluting the pulp suspension and producing a board on a paper machine, surface sizing the board using at least one starch-containing suspension, and drying the paper structure to a dry content between 4% and 17%.

2. The method according to claim 1, wherein the pulp suspension has a material density between 1% and 10%.

3. The method according to claim 1, wherein the proportion of the first pulp type in the finished board is between 10% and 50%.

4. The method according to claim 1, wherein the proportion of the second pulp type in the finished board is between 90% and 50%.

5. The method according to claim 1, wherein the second pulp is selected from a group of pulps which comprises natural pulps, refiner mechanical pulp (RMP), chemi refiner mechanical pulp (CRMP or CMP) or chemi-thermomechanical pulp (CTMP), pressurised refiner mechanical pulp (PRMP), semi-chemical pulp, high-yield chemical pulp, chemical pulp, alkaline pulp, all of the aforementioned pulps in the form of fresh fibres or also as recycled fibres of the medium or high grades in accordance with EN 643:2001, group 2 or group 3.

6. The method according to claim 1, wherein the second pulp type is a mixture of 10% to 60% short-fibre pulp, and 90% to 40% long-fibre pulp.

7. The method according to claim 1, wherein the mixing and/or the swelling are performed at a predefined material density between 0.1% and 15% over a time between 2 minutes and 10 minutes, and at a temperature between 10° C. and 70° C.

8. The method according to claim 1, wherein the starch is a potato, a maize or a wheat starch.

9. The method according to claim 1, wherein the sizing agent for hydrophobing the cellulose fibres is a resin size, or a synthetic sizing agent, and is combined with a natural or synthetic polymer.

10. The method according to claim 1, wherein the board produced on the paper machine has a mass per unit area between 35 g/m2 and 600 g/m2.

11. The method according to claim 1, wherein the surface sizing is performed with at least one starch suspension, wherein the starch suspension alternatively comprises at least one further additive, which is selected from the group which comprises carboxymethyl cellulose, glyoxal, polymer sizing agent, dry strength agent, wet strength agent, resin size, and synthetic sizing agents.

12. The method according to claim 1, wherein the grinding is performed in a Hollander with a power up to 200 kW, Papillon Refiner with a power between 100 and 3600 kW, a single-disc refiner, a twin-disc refiner, a twin-refiner, a flat cone crusher and/or a steep cone crusher with a power between 90 kW and 2800 kW or a disc mill with a power between 315 kW and 2500 kW.

13. The method according to claim 1, wherein the pulp is dispersed prior to the grinding.

14. The method according to claim 1, wherein the board is smoothed in the paper machine and/or offline by means of a calender, under predefined conditions in respect of the temperature, compressive stress, duration, number of nips, elastic properties of the rollers and the web moisture.

15. The method according to claim 1, wherein the first pulp type is selected from a group which contains spiked grasses, meadow grasses and spiked meadow grasses, as well as sedges of the genera Poaceae and Cyperaceae, grasses of the subfamilies Anomochlooideae, Pharoideae, Puelioideae, Bambusoideae Ehrhartoideae, Pooideae, Tribus Aveneae, Tribus Poeae, Tribus, Triticeae Aristidoideae, Danthonioideae, Arundinoideae, Chloridoideae, Centothecoideae, Panicoideae, Saccharum officinarum and Micrairoideae, and Agrostis canina—velvet bentgrass; Agrostis capillaris—common bent; Agrostis stolonifera—creeping bent; Agrostis vinealis—brown bent; Aira caryophyllea—silver hairgrass; Aira praecox—early hairgrass; Alopecurus geniculatus—water foxtail; Alopecurus myosuroides—slender meadow foxtail; Alopecurus pratensis—meadow foxtail; Ammophila arenaria—marram grass; Anthoxanthum aristatum—awned vernalgrass; Anthoxanthum odoratum—sweet vernalgrass; Apera Spica-venti—lose silky-bent; Arrhenatherum elatius—bulbous oat grass; Avena fatua—common wild oat; Avena sativa—common oat; Brachypodium pinnatum—heath false brome; Brachypodium sylvaticum—false brome; Briza maxima—big quaking grass; Briza media—common quaking grass; Bromus arvensis—field brome; Bromus benekenii—Denver brome; Bromus carinatus—California brome—mountain brome; Bromus erectus—erect brome; Bromus hordeaceus—soft brome; Bromus inermis—awnless brome; Bromus madritensis—compact brome; Bromus secalinus—rye brome; Bromus sterilis—barren brome; Bromus tectorum—downy brome; Calamagrostis arundinacea—reed grass; Calamagrostis epigejos—wood small-reed; Catapodium rigidum—fern-grass; Coix lacryma-jobi—adlay; Cortaderia selloana—pampas grass; Corynephorus canescens—grey hair-grass; Cynodon dactylon—dog's tooth grass; Cynosurus cristatus—rested dog's tail; Dactylis glomerata—cock's foot; Danthonia decumbens—heath grass; Deschampsia cespitosa—tufted hairgrass; Deschampsia flexuosa—wavy hair-grass; Deschampsia setacea—bog hair-grass; Digitaria ischaemum—smooth crabgrass; Digitaria sanguinalis—purple crabgrass; Echinochloa crus-galli—common barnyard grass; Echinochloa muricata—rough barnyard grass; Elymus caninus—bearded couch; Elymus repens—couch grass; Eragrostis albensis—Elbe lovegrass; Eragrostis curvula—weeping lovegrass; Eragrostis minor—small lovegrass; Eragrostis multicaulis—Japanese lovegrass; Festuca arundinacea—tall fescue; Festuca filiformis—fine-leaf sheep fescue; Festuca gigantea—giant fescue; Festuca pratensis—meadow fescue; Festuca rubra—red fescue; Glyceria fluitans—floating sweet-grass; Glyceria maxima—great manna grass; Glyceria maxima—great manna grass; Helictotrichon pratense—meadow oat-grass; Helictotrichon pubescens—downy oat-grass; Helictotrichon pubescens—downy oat-grass; Holcus lanatus—tufted grass; Hordelymus europaeus—wood-barley; Hordeum jubatum—foxtail barley; Hordeum murinum—wall barley; Hordeum vulgare—common barley; Koeleria macrantha—crested hair-grass; Koeleria pyramidata—prairie Junegrass; Lolium multiflorum—Westerwolds ryegrass; Lolium perenne—perennial ryegrass; Lolium remotum—flaxfield ryegrass; Lolium temulentum—darnel ryegrass; Melica ciliata—hairy melic; Melica nutans—mountain melick; Melica uniflora—wood melick; Milium effusum—wood millet; Miscanthus floridulus—Pacific Island silvergrass; Miscanthus sacchariflorus—Amur silvergrass; Miscanthus sinensis—Chinese silvergrass; Miscanthus sinensis ‘Variegatus’—Chinese silvergrass; Miscanthus sinensis ‘Variegatus’—Chinese silvergrass; Molinia arundinacea—Moor grass; Molinia caerulea—purple moor grass; Nardus stricta—matgrass; Panicum capillare—witchgrass; Panicum miliaceum—proso millet; Panicum riparia—panic grass; Pennisetum setaceum—crimson fountain grass; Pennisetum villosum—feathertop grass; Phalaris arundinacea—reed canary grass; Phalaris canariensis—canary grass; Phleum phleoides—Boehmer's cat's tail; Phleum pratense—timothy grass; Phragmites australis—common reed; Poa annua—annual meadow-grass; Poa bulbosa—bulbous bluegrass; Poa chaixii—broad-leaved meadow-grass; Poa compressa—flattened meadow-grass; Poa nemoralis—wood bluegrass; Poa palustris—fowl bluegrass; Poa pratensis—Kentucky bluegrass; Poa trivialis—rough meadow-grass; Polypogon monspeliensis—annual beard-grass; Puccinellia distans—weeping alkaligrass; Secale cereale—rye; Sclerochloa dura—common hardgrass; Setaria italica—foxtail millet; Setaria pumila—yellow foxtail; Setaria verticillata—hooked bristlegrass; Setaria viridis—green foxtail; Sorghum bicolor—sorghum; Sorghum halepense—Johnson grass; Trisetum flavescens—yellow oatgrass; Triticale; Triticum aestivum—common wheat; Triticum dicoccon—Emmer; Triticum durum—durum wheat; Triticum monoccocum—einkorn wheat; Triticum spelta—dinkel wheat; Vulpia myuros—rat's tail fescue; Zea mays—maize, meadow grass, sport and utility grass, Festuca, Lolium perenne, Poa pratensis, Agrosti, sedges of the genus Carex, combinations hereof and the like, and seagrass or algae selected from a group containing Zostera seagrass genera and the species Zostera angustifolia Hornem. Rchb., Zostera asiatica Miki, Zostera caespitosa Miki, Zostera capensis Setch., Zostera capricorni Asch., Zostera caulescens Miki, Zostera japonica Asch. & Graebn., common seagrass Zostera marina L., Zostera mucronata Hartog, Zostera muelleri Irmisch ex Asch., dwarf eelgrass Zostera noltii Hornem., Zostera novazelandica Setch., Zostera tasmanica M. Martens ex Asch., Heterozostera and Phyllospadix, Posidonia Neptune grasses from the Posidoniaceae family, Cymodocea, Halodule, Syringodium and Thalassodendron from the Cymodoceaceae family and Enhalus acoroides, Halophila and Thalassia from the Hydrocharitaceae family, subfamily Halophiloideae, or Glaucophyta, Haptophyta, Cryptista (Cryptophyta), Euglenozoa, Dinozoa s. Dinoflagellates, Raphidophyceae Chloromonadophyceae, Chlorarachniophyta, yellow-green algae Xanthophyceae, golden algae (Chrysophyta), Bacillariophyta diatoms, Phaeophyta brown algae, Rhodophyta red algae, Chlorophyta green algae, Picobiliphyta, Heterokontophyta, Excavata, Stramenopile, Haptophyta, Cryptophyta, Chlorarachniophyta and Heterokontophyta, Alveolata, Biliphyta, combinations hereof and the like.

16. The method according to claim 1, wherein the first pulp type is Silphie (Silphium perfolatium).

17. The method according to claim 1, wherein at least one further pulp from one of the two pulp types is admixed to the mixed ground pulp after the grinding.

18. The method according to claim 1, wherein the board is brushed or coated partially or fully on the upper side and/or lower side with a sealing lacquer prior to production of the liquid packaging.

19. The method according to claim 18, wherein the sealing lacquer is applied with a weight per unit area between 5 and 15 g/m2.

20. The method according to claim 18, wherein the sealing lacquer is a hot sealing lacquer used for integrally bonded connection of the board.

21. The method according to claim 1, wherein the board is printed by flexographic or offset printing.

22. The method according to claim 1, wherein the board has a surface KIT value of greater than 3.

23. Use of a board which is produced by the method of claim 1 for production of a liquid container, a vase, a plant pot, a beverage container, or a beverage cup.

Description

[0066] FIGS. 1 and 2 show a practical example for the grass-containing liquid container 1, in which the board according to the invention has been used to produce a bowl for food, in particular moist food. The area density of the board for producing the model was 300 g/m.sup.2. In FIG. 1, a view from above is shown, and in FIG. 2 a view from below is shown, wherein the base surface 5 is delimited by the side faces 3, 6, 8 and 10. In the overlap regions, of which positions 2, 4 and 7 can be seen in the illustration, the faces have been connected in an integrally bonded manner by means of the used sealing lacquer. This results in a water-resistant bowl form, with a hydrophobic surface, which only experiences water permeability after 4 hours. The edge region of the overlap between the side faces 7 and 10 can also be seen at reference sign 9.

[0067] Alternative embodiments, such as coffee cups and the like, can of course also be produced from a corresponding material, wherein here the overlap regions are also connected in an integrally bonded manner using sealing lacquer (for example base and sides in the case of a cylindrical basic form).

[0068] The corresponding board was produced as follows: [0069] Pulp composition: grass fibres 30%, long-fibre pulp 70%. [0070] Pulp preparation: 5 minutes swelling of the pulp at 25° C. and continuous mixing and a material density of 5%. Subsequent griding of the pulp using a flat cone refiner and with an energy input of 2000 kW to a degree of dewatering of 55° SR. Addition of 2% cationic starch as additive in the mass and dilution of the pulp suspension to 0.5% material density to produce the board web on a paper machine. [0071] Surface sizing of the board web in an online size press, wherein the size liquor has a material density of 10% and comprises starch and AKD as sizing agent. [0072] Drying of the board web to a residual moisture content of 7%

[0073] The corresponding board web was cut in order to produce the food bowl and, prior to folding, was coated with a sealing lacquer in an application amount of 10 g/m.sup.2, so that the overlap regions were connected in an integrally bonded manner to the sealing lacquer. The food bowl thus produced has a Kit value of 6.3 and can be used both for moist and very moist food. Moisture penetration occurs only in a time period of more than 4 hours. It is particularly advantageous that not only can primary pulp be spared due to the selected pulp composition, but that a fully recyclable or compostable packaging system is provided in comparison to food packaging known from the prior art.