WO2022117837A1

WO2022117837A1 - Net

Info

Publication number: WO2022117837A1
Application number: PCT/EP2021/084208
Authority: WO
Inventors: Rudolf Einsiedel; Matthias MIELKE
Original assignee: Cordenka Innovations GmbH
Priority date: 2020-12-04
Filing date: 2021-12-03
Publication date: 2022-06-09
Also published as: DE102020132307A1; EP4256118A1; CN114592276A

Abstract

Described is a net containing two groups of cellulose yarns, wherein the groups cross one another, characterised in that the yarns of one group essentially contain cellulose multi-filaments and the yarns of the other group contain cellulose multi-filaments and/or cellulose staple fibres. The net can be used more particularly to pack agricultural products such as bales of hay and straw.

Description

network

Description:

The invention relates to a net which is suitable for packaging agricultural, forestry and horticultural products, in particular hay bales and straw bales.

The cultivation of grain is one of the most important cultural achievements of mankind. Depending on the region of the world, other types of grain play a role, namely rice, corn, rye, oats, millet or various types of the botanical genus Triticum, which includes the various types of wheat as well as spelt, emmer and einkorn.

What all of these types of grain have in common is that they are representatives of the botanical family of sweet grasses and that, in addition to the seeds that are important for human nutrition, they also produce large amounts of stalk material, which is a by-product after the seeds are threshed out. Dry stalk material resulting from threshing processes is commonly referred to as "straw". Straw material consisting of cut and dried grass that has not undergone a threshing process is referred to as "hay".

Hay is a valuable fodder that is primarily used by livestock that cannot tolerate fermented fodder (silage) (horses) or that cannot be fed with silage for reasons of use. Mention should be made here in particular of cows whose milk is marketed as so-called "hay milk" or used for the production of particularly high-quality raw milk cheeses. Straw, on the other hand, is primarily important as a bedding material for traditionally run stables.

What hay and straw have in common is that they are produced during the summer months but have to be stored for the whole year. Storage that is protected from moisture in particular is essential for storage in order to prevent the growth of mold, for example. Whereas hay and straw used to be stored as loose material on "haylofts" under the roofs of farmhouses or in barns, during the 20th century storage in the form of compressed bales, which were stabilized by wrapping them with string or nets, became more common. For hay and straw bales, there are both cuboid and roll-shaped designs, with the roll shape (“round bales”) being the dominant form in recent years.

In the round baler used to make round bales, the hay or straw picked up from the field is formed into a strand which is compacted and rolled up into a compact, cylindrical bale. The bale is then wrapped in a net to stabilize it.

High stability requirements are placed on the nets used for packaging, since their task is to keep the compacted bales in shape against significant counterforces for months, sometimes for a year or even several years. For this reason, nets made of tear-resistant synthetic fibers such as polyethylene, polypropylene, polyamide or polyester are usually used for this purpose. Since synthetic fibers of this type are generally produced from fossil raw materials, their use is not without concerns for ecological reasons, particularly with regard to their disposal properties.

Surprisingly, it has now been shown that the disadvantages of the prior art are overcome by a network containing two groups of cellulosic yarns, the groups crossing each other, characterized in that the yarns of a group essentially contain cellulosic multifilaments and that the yarns of the other group contain cellulose multifilaments and/or cellulose staple fibers.

In the present application, the wording "essentially ... contained" means that the mass fraction of the component mentioned is at least 60%. However, the mass fraction of said component can also be 100%.

A network within the meaning of the present application is a flat structure made of yarns connected to one another that forms stitches that take up more space than the game itself by a factor of two. It is typical of networks within the meaning of the application that they do not restrict the passage of gases and liquids, or restrict them only to a small extent.

Yarns within the meaning of the present application are one-dimensional structures made of fibers, the fibers being aligned largely parallel to one another and, depending on the character of the fibers and the yarn, can be connected to one another by twisting, twirling, gluing or welding. The fibers that make up a yarn can also be in the form of a yarn in such a way that several first yarns are connected to one another in such a way that a second yarn is obtained. It is possible, for example, to twist two or more first yarns together to obtain a second yarn. Games made by twisting other games are known to those skilled in the art as "twisting" and their manufacture by twisting yarns is known as "twisting".

Depending on the type of fibers used, filament yarns and staple fiber yarns can be distinguished. In addition, in the present application, the term "yarn" also includes all other filamentous structures from which nets can be produced, namely, for example, all types of threads, tapes such as plastic tapes or film strips, for example made of plastic films. In the further course of the application, the terms “yarn” and “thread” are used synonymously.

Filaments within the meaning of the present application are fibers whose length is almost infinite in relation to their thickness. A typical filament has one length of one meter or more, but the length can also be several hundred and even several thousand meters. It is therefore conceivable, for example, that the content of a complete yarn spool consists of just a single filament. Filaments typically arise in processes in which streams of spinnable liquids are solidified in a controlled manner, as is the case, for example, in the formation of natural fibers such as silk or spider threads, but especially in the artificial production of fibers from solutions or melts.

A staple fiber within the meaning of the application has a length in the range from a few hundred micrometers to a few centimeters. Most known natural fibers are staple fibres, such as cotton, flax, hemp, kenaf, sisal, ramie, jute or cellulose derived from wood. However, staple fibers can also be obtained by crushing filaments. Cellulose staple fibers produced by crushing cellulose filaments are known to those skilled in the art as "rayon staple".

Cellulosic fibers in the context of the application are all fibers based on the biopolymer cellulose, but in particular cotton fibers, flax fibers, hemp fibers, kenaf fibers, sisal fibers, ramie fibers, jute fibers or those based on pulp obtained from wood. In addition, cellulose fibers are also understood to mean chemical cellulose fibers such as lyocell fibers, viscose fibers or cupro fibers. All natural fibers derived from plants are cellulose fibers. In terms of length, all cellulosic fibers derived directly from plants are cellulosic staple fibers. Cellulosic filaments can be made from plant-derived cellulose by processes that bring the cellulose to a liquid form, which is then converted back to solid cellulose via the intermediate stage of liquid jets becomes.

A distinction is made between chemical and physical processes in the processes used to convert cellulose into a liquid form. Corresponding chemical processes, which are also known to those skilled in the art as "regenerate processes", are based on bringing the cellulose into a soluble form by chemical modification, then producing jets of liquid from the corresponding solution and subsequently subjecting the liquid jets to chemical conditions which reverse the chemical modification of the cellulose and thus allow the liquid jets to form cellulose filaments. Chemical modifications suitable for this purpose are, for example, conversion into cellulosic anthate (known to those skilled in the art as the "viscose process" or "xanthogenate process") or into the phosphoric acid ester of cellulose (also known to those skilled in the art as the "Bocell process" or "Akzo process"). . In both processes, the chemical modification of the cellulose is achieved by introducing the jets of liquid into a suitable coagulation bath, in which the chemical modification of the cellulose is reversed.

Physical processes to bring cellulose into a soluble form are known to those skilled in the art as “direct dissolving processes”. They are based on the fact that the cellulose is dissolved directly in a suitable medium without undergoing any chemical change. Mention should be made in this context of the Cupro process, in which an ammoniacal solution of tetramine copper(II) hydroxide is used as the solvent, and the Lyocell process, in which N-methylmorpholine N-oxide (NMMO) is used as the solvent . Ionic liquids are also used as solvents. In all cases, jets of liquid are generated from the solution and fed into a suitable precipitation bath, in which the cellulose precipitates out of the solution and forms cellulose filaments.

Cellulose filament yarns are notable for their particularly high strength, which makes them ideal strength members in nets according to the invention. In addition, cellulose multifilament yarns produced using the viscose process exhibit pronounced so-called wet shrinkage. Contact with water can reduce their length by up to 15%. The extent of wet shrinkage is dependent on the degree of stretching of the cellulose multifilament yarn as well as on the degree of twisting or twisting and can be controlled and adjusted to a desired value as a result.

Surprisingly, wet shrinkage has been found to be particularly beneficial in netting used to wrap bales of straw and hay. as they contract due to moisture shrinkage when they come into contact with water, compress the packaged goods and thus counteract water absorption by the packaged goods. This is all the more the case since the contracting net also counteracts swelling of the packaged goods due to water absorption.

In one embodiment, the wet shrinkage of at least one cellulosic multifilament yarn is at least 12%. In one embodiment, the wet shrinkage of at least one cellulosic multifilament yarn is at least 10%. In one embodiment, the wet shrinkage of at least one cellulosic multifilament yarn is at least 8%. In one embodiment, the wet shrinkage of at least one cellulosic multifilament yarn is at least 6%. In one embodiment, the wet shrinkage of at least one cellulosic multifilament yarn is at least 5%.

Compared to prior art nets, cellulose multifilament yarns also have the advantage that they do not show the creep behavior that is the case with the yarns otherwise used which are based on thermoplastics. The creep behavior of the cellulose multifilament yarns in the nets according to the application is much less pronounced than in the yarns of the prior art. Cellulosic multifilament yarns retain their length even under long-term tension and are therefore particularly suitable for use in hay and straw bale nets, in which they are sometimes stored under tension for months. Furthermore, because there is no need to counteract creep of the material, using a net according to the application makes it possible to wrap the bale with less material than is necessary with the thermoplastic materials of the prior art. When using a net made of polypropylene, a round bale usually has to be wrapped about 3.2 times in order to achieve the necessary stability, while when using a net according to the application only 2 or 2.5 wrappings are necessary to achieve a long-term stable bale. In this way it is possible to increase the number of turns compared to the prior Technique to reduce to 62-78%. At the same time, the wrapping time is shortened to the same extent and the corresponding amount of material is saved.

In one embodiment, the yarns of the net according to the application have a titer of at least 820 dtex. In one embodiment, the titre of the yarns of the net according to the application is at least 950 dtex, 1100 dtex or 1300 dtex. The game titer is also known to those skilled in the art as “effective fineness”.

The high strength of cellulosic yarns, in particular cellulosic multifilament yarns, allows the distances between the yarns in the nets according to the application to be larger than in the prior art nets, where distances of about 2.5 cm are usual. In one embodiment, the longitudinal threads of the net according to the application are at least 2.5 cm, at least 3 cm, at least 3.5 cm, at least 4 cm or at least 5 cm apart.

The nets according to the application have at least two groups of threads. In one embodiment, the threads of each group run essentially parallel to one another. "Essentially parallel" means that the threads of a group do not cross. A group of yarns can run in the machine direction. Depending on the processing technique, this group of threads is known to the person skilled in the art under terms such as “warp” or “flutter” but also simply as “longitudinal threads”.

A second group of threads crosses the threads of the first group. This type of thread is known to those skilled in the art, e.g. under the designation "weft" or simply as "cross threads".

The wrapping of hay and straw bales is typically done with the net in the machine direction. In one embodiment, the threads running in the machine direction are therefore exposed to particularly strong mechanical loads and therefore act as reinforcements. In one embodiment, the threads running in the machine direction essentially contain cellulose multifilament yarns. The primary task of the transverse threads is to hold the net together, to cover the crop and to provide the necessary mechanical grip. In one embodiment, yarns which essentially contain cellulosic staple fibers are preferably used for the threads running in a cross-machine direction.

In the present application, the term “substantially” means a proportion of at least 60% by weight, in embodiments at least 70%, 80%, 90% or 100%. However, the transverse threads can also consist of 100% cellulose multifilament yarn.

The net according to the invention can be produced from cellulosic yarns by any method known to those skilled in the art. For example, manufacture by knotting, weaving, warp-knitting or knitting is conceivable.

In one embodiment, the net according to the invention is in the form of knitwear. In one embodiment, the net according to the invention is formed as a knitted fabric. In one embodiment, it is a knitted fabric. In one embodiment, it is a tubular knitted fabric. In one embodiment, it is a Raschel knitted fabric.

In one embodiment, the yarns used to produce the network according to the invention consist of at least 60% by mass of cellulose staple fibers. In one embodiment, the yarns used to produce the net according to the invention consist of at least 70% by mass of cellulose staple fibers. In one embodiment, the yarns used to produce the net according to the invention consist of at least 80% by mass of cellulose staple fibers.

In one embodiment, the yarns used to produce the net according to the invention consist of at least 60% by mass of cellulose filaments. In one embodiment, the yarns used to produce the net according to the invention consist of at least 70% by mass of cellulose filaments. In one embodiment, the yarns used to produce the net according to the invention consist of at least 80% by mass of cellulose filaments. In one embodiment, the threads used to produce the net according to the invention consist of 100% by mass of cellulose filaments.

The games contained in the network can be colored in whole or in part for color identification or design of the network according to the invention. Dyeing is technically particularly easy to achieve with staple fiber yarns, since staple fibers accept dyes more easily than filaments. By adding dyes or pigments to the viscose solution, spun-dyed cellulose multifilaments can also be produced. By twisting in dyed staple fiber yarns or spun-dyed cellulose multifilaments, the colored design of the nets according to the invention is possible in a particularly efficient manner. This is not only for design reasons, but also for practical reasons, as it is possible in this way to easily mark nets with certain properties such as mesh size, yarn thickness or strength.

In one embodiment, the nets are constructed in such a way that they can be completely composted in accordance with AS 5810 and/or NF T 51-800 under the usual undemanding conditions in the home and garden area. As a result, the disposal of disused and unusable networks can be made significantly easier. In addition, this means an enormous simplification of the disposal, e.g. The possibility of subsequent use as compost or through fermentation in biogas plants can solve practical disposal problems and turn them into sustainable recycling processes.

If, according to the application, the net is made exclusively from cellulosic yarns, it can even be digestible for certain farm animals, in particular ruminants such as cattle, goats or sheep. Damage to the health of livestock due to residues of nets accidentally getting into the feed, as is usual with prior art nets, is thus ruled out. What is more, the net according to the application can even be fed to livestock chewing the cud together with the content (eg hay). A further contribution can therefore be made to reducing unwanted plastic inputs into soil, water and the food chain.

The network according to the application can be designed either as a flat structure or as a tubular structure. Flat structures are particularly suitable for consolidating agricultural products such as round or cuboid hay and straw bales. Tubular nets are particularly suitable for holding Christmas trees.

The application also relates to a sack, pouch or bag which contains nets according to the application and which can be used for packaging comparatively robust agricultural, forestry or horticultural products such as potatoes, onions, cabbages, pome fruit or firewood . Depending on the size, corresponding sacks, bags or bags can be used for transporting large quantities or for selling small quantities in retail. In the case of firewood packaging, the sack, bag or bag can also be burned according to the application without any additional odor nuisance or environmental pollution.

The invention also relates to the use of the net according to the invention, or sacks made from it, for packaging agricultural, forestry and horticultural products such as Christmas trees, rooted trees or shrubs, straw bales, hay bales, cotton bales or cotton modules or banana trees.

Claims

Expectations:

1 . Net containing two groups of cellulose yarns, the groups crossing each other, characterized in that the yarns of one group essentially contain cellulose multifilaments and that the yarns of the other group contain cellulose multifilaments and/or cellulose staple fibers.

2. Network according to claim 1, wherein the network is woven, warp-knitted, knotted or knitted.

3. The net of claim 2, wherein the net is a Raschel knit.

4. Network according to one or more of the preceding claims, wherein the yarns of at least one group are twisted.

5. Net according to one or more of the preceding claims, wherein the distance between the yarns of at least one group is at least 2.5 cm, preferably at least 3 cm, even more preferably at least 4 cm, particularly preferably at least 5 cm.

6. Network according to one or more of the preceding claims, wherein the cellulose multifilament yarns are produced by the viscose, the cupro or by direct dissolving processes, such as the lyocell process.

7. Network according to one or more of the preceding claims, wherein the cellulose staple fiber yarns contain viscose staple fibers, cotton, hemp fibers or jute fibers.

8. Network according to one or more of the preceding claims, wherein one or more staple fiber yarns are dyed.

9. Net according to one or more of the preceding claims, wherein one or more cellulosic multifilament yarns are dyed.

10. Net according to one or more of the preceding claims, wherein the net according to DIN EN 13432 is biodegradable.

11 . Net according to one or more of the preceding claims, wherein the net is biodegradable according to AS 5810 and/or NF T 51 -800.

12. Sack, pouch or bag for holding agricultural products such as potatoes, cabbages, pome fruit or firewood containing at least one net according to one or more of the preceding claims.

13. Use of a network according to one or more of claims 1 to

11 for packaging agricultural products such as Christmas trees, rooted trees or shrubs, straw bales, hay bales, cotton bales or banana trees.