Training cord

Abstract

Training cord, wherein the training cord is biodegradable and contains cellulosic yarns, characterized in that the cellulosic yarns are multifilament yarns which are locally intermingled with one another and in that the training cord is bulked. The invention further relates to a method for producing said training cord. The field of application of said training cord relates to horticulture and agriculture, in particular greenhouse cultivation, for example of fruiting vegetables such as tomatoes, aubergines, peppers and cucumbers.

Description

[0001] CRD3315

[0002] Guide cord II

[0003] Description:

[0004] The invention relates to a guide cord for use in horticulture and agriculture.

[0005] The cultivation of various climbing plants is important for human nutrition and the production of food and beverages. These include twining plants, whose shoots wind around an object, as is the case with hops, for example. Also important are plants from the group of tendril climbers, which develop their own shoots with which they cling to supports. Examples include grapevines, raspberries, beans, peas, as well as cucumbers, zucchini, and other cucurbits. Finally, plants from the group of sprawling climbers also play a role; these find their support by developing lateral shoots. Examples of this group include...

[0006] Blackberries or, as fruits of particular economic importance, tomatoes, peppers and eggplants.

[0007] To provide climbing plants with optimal growing conditions, the provision of trellises or supports is essential. In viticulture, permanent trellises or pergolas are typically used for this purpose, while hop plants are usually trained on iron wires. These supports offer the necessary stability and rigidity to withstand adverse weather conditions, especially strong winds, over a long period, sometimes for years or even decades. However, most commercially cultivated climbing plants are significantly shorter-lived than grapevines and are therefore unsuitable for cultivation on permanent supports. Furthermore, at least in Europe, they are generally grown in greenhouses. In greenhouse cultivation, for example, tomatoes are trained on strings, which are usually disposed of along with the plant remains at the end of the growing season.Synthetic fiber cords, such as polypropylene, are commonly used for this purpose. These provide the necessary strength to support, for example, heavy tomato fruits, while also being flexible enough to be wound onto the tying hooks commonly used in tomato cultivation. A flexible material is required that does not deform plastically or elastically under the sometimes heavy load. Another requirement is that the support cord should offer the plant sufficient grip so that the tendrils or shoots can essentially "hold on" to it. Therefore, threads that are too smooth are unsuitable.

[0008] This requirement profile is generally met by polymer-based twine. However, a disadvantage is the non-biodegradable material, which prevents composting of the plant material together with the twine residue. Instead, such plant remains must be disposed of as regular waste, for example by burning, and are not available as raw material for compost or as mulch.

[0009] To create an ecologically and economically sensible alternative to the use of plastic cords in greenhouse cultivation, experts are familiar with support cords made from biodegradable yarns, which can be based on natural fiber yarns such as cotton, jute, sisal or hemp, but also on cellulose-based fibers such as viscose or lyocell.

[0010] Cellulose-based fibers can act as load-bearing elements due to their high tensile strength; however, yarns made from them are generally considered too smooth to provide sufficient support for climbing plants. Therefore, conventional biodegradable trellis cords always contain at least a proportion of staple fiber yarn to achieve the necessary roughness. DE 19757701 A1 discloses a biodegradable climbing aid that is particularly suitable for growing hop plants.

[0011] It has now surprisingly been shown that a guide cord, according to the present application, is able to provide sufficient support for climbing plants of all kinds.

[0012] This task is solved by a guide cord, wherein the guide cord is biodegradable according to DIN EN 13432 and contains cellulosic yarns, characterized in that the cellulosic yarns are multifilament yarns which are irregularly locally or continuously twisted or intertwined and that the guide cord is puffed up.

[0013] The swirling of the cellulosic multifilament yarn can be achieved, for example, using methods known to those skilled in the art as intermingling, air texturing, or tangle-making. The term "irregular" refers to a structure that cannot be described using simple means and that, over a length of at least half a meter of the guide cord, does not exhibit regularly recurring structural motifs, as is the case, for example, with a twist. Instead, the individual filaments of the multifilament yarns are arranged irregularly.

[0014] In this application, the term "biodegradable" refers to products or substances which, under suitable environmental conditions, are completely degraded within a period of a few days to one year by microorganisms present in the environment, such as bacteria, algae and fungi, into substances that are again available to biological cycles.

[0015] The standards AS 5810 and NF T 51-800 define conditions that goods of any kind must meet in order to be biodegradable under the conditions of usual composting applied in home gardens.

[0016] In contrast, the standards DIN EN 13432 and ASTM D6400 define biodegradation under industrial conditions such as elevated temperature and humidity.

[0017] Filaments, as defined in this application, are structures whose length is almost infinitely large relative to their thickness. In particular, filaments are understood to be fibers of exceptionally great length. A typical filament has a length of one meter or more, but the length can also be several hundred or even several thousand meters. Filaments are typically formed in processes in which streams of liquids are brought to a controlled solidification, as is the case, for example, in the formation of natural fibers such as silk or spider silk, but especially in the artificial production of fibers from solutions or melts.

[0018] Staple fibers are different from filaments. These are fibers that are short compared to filaments. Typical staple fibers range in length from a few millimeters to a few centimeters. While staple fibers made from synthetic polymers are generally obtained by cutting filaments, the vast majority of natural fibers such as cotton, jute, hemp, sisal, or wool are staple fibers.

[0019] A multifilament yarn within the meaning of the present application is a yarn consisting of several parallel filaments that are wound, unwound, and handled together, but which are not, or only very weakly, connected to one another. The connection of the individual filaments in a multifilament yarn is usually achieved by continuous twisting or localized swirling of the individual filaments, but can also be achieved by localized welding or bonding. Cellulose multifilament yarns can be produced by various processes. All these processes have in common that the cellulose, optionally after chemical modification, is converted into a soluble form and dissolved. The dissolved form thus obtained is forced through nozzles, and after passing through the nozzle, a controlled precipitation of the liquid jets is initiated, during which the cellulose regenerates. Essential processes of this type are known to those skilled in the art.Examples include the viscose process, the cupro process and the direct dissolution process, in which the cellulose is dissolved in a suitable solvent, such as N-methylmorpholine N-oxide or ionic liquids.

[0020] Additives such as pigments or functional additives can be added to the liquid before the spinning process. Coloring with pigments during the spinning process has the advantage that the color is significantly more permanent than coloring after spinning, as it is achieved by pigments embedded in the filament material. Generally, coloring the guide cord is advantageous for clearly identifying cords with different properties, such as varying thicknesses or breaking strengths, or when different colors are beneficial in specific applications. For example, using different colors can allow for the differentiation of plant shoots.

[0021] The multifilament yarns of the guide cord according to the invention are connected to one another by twisting. Twisted yarns are known to those skilled in the art as yarns that are connected to one another by irregular entanglements of the individual filaments. Twisting thus contrasts with other joining techniques such as twisting or cording, in which the yarn itself and / or individual strands of the yarns exhibit a regular, easily quantifiable twist (e.g., in turns per centimeter), resulting in a helical shape. Twisting also contrasts with other joining techniques such as gluing, in which the individual filaments are joined by a continuously or spot-applied adhesive, and welding, in which the individual filaments are completely or partially melted and thus connected to one another by their own material.

[0022] The swirling effect is typically introduced into the yarn by an airflow. For this purpose, the yarn is guided through or past a swirling nozzle, with an airflow simultaneously passing through the nozzle to create the swirling effect. The airflow can be continuous or pulsed. The pulses of a pulsed airflow can be regular or irregular.

[0023] Typically, the timing of regularly placed pulses is correlated with the game's running speed in such a way that a specific number of so-called tangent points per meter results. In one embodiment, the yarn has 2 to 20 tangent points per meter.

[0024] The swirling process is accompanied by a swelling of the yarn. Swelling, in this context, refers to the increase in yarn volume without the addition of further material. Swelling therefore means that the amount of air or gas enclosed by the individual filaments is increased. This reduces the density of the yarn, while simultaneously increasing its surface area and roughness, resulting in improved grip and adhesion to the stems, shoots, or tendrils of plants being trained along the guide wire. The guide wire according to the present application thus provides plants with better support than guide wires of the prior art.

[0025] Furthermore, twisting is an extremely efficient process compared to twisting, gluing, or welding. Spinning or twisting machines, which impart a true twist to the yarn, are technically very complex devices that subject the yarn to considerable mechanical stress both parallel to and perpendicular to its direction of travel. In addition to the tension placed on the yarn during the twisting process, there are also adverse effects from friction. Finally, twisting or stranding is a comparatively slow process.

[0026] Swirl nozzles are technically simpler in design than spinning or twisting machines; they are smaller, contain fewer moving parts, and subject the yarn to less mechanical stress in terms of both tension and friction. Ultimately, the processing speed of swirl nozzles is significantly higher than that of spinning or twisting machines, allowing a larger quantity of yarn to be processed into piping cords in a shorter time, resulting in a considerable economic advantage. Another advantage of swirl production is that the resulting yarns are structurally much more flexible than those produced by twisting. While twisted yarns always have a circular cross-section, swirl yarns can be formed into any desired cross-sectional shape.

[0027] It has now surprisingly been shown that the tensile strength or load-bearing capacity of guide cords produced by twisting is sufficient to meet the high tensile strength requirements placed on guide cords.

[0028] The tensile strength or load-bearing capacity is a crucial criterion for the suitability of a support string for cultivating a specific climbing plant. It must be considered that, under certain circumstances, the support string must bear the weight of an entire plant, potentially including large and heavy fruits such as beans, raspberries, blackberries, grapevines, hops, tomatoes, peppers, eggplants, zucchini, or cucumbers. Furthermore, climbing plants in greenhouses can reach considerable heights of several meters, meaning that a suitable support string must bear the weight of a plant of significant size. Depending on the climbing plant being trained, support strings are also subjected to considerable stress from repeated and mechanical harvesting of fruits. A support string according to the invention achieves a specific tensile strength previously unattainable for biodegradable support strings.Since it is not necessary to blend the guide line with comparatively low-tensile, heavy, and bulky staple fiber yarns, the guide line can be made thinner and lighter while maintaining the same or even higher tensile strength, which significantly simplifies logistics. Larger quantities of guide line of the same or better quality can thus be transported from the same spool volume. The reduced weight also makes the line easier to handle. Another advantage of thinner lines made from cellulose multifilament yarns is their reduced tendency to shade surrounding plants for two reasons. First, thinner lines cast less shade than thicker ones; second, lines made from cellulose multifilament yarns typically have a high reflectivity and therefore absorb less light, which is thus available to the surrounding plants for their growth.Furthermore, material in the form of expensive staple fiber gels, which previously had to be added to increase the roughness of a guide cord and also complicated the manufacturing process, is saved. The tensile strength of a guide cord according to the invention, relative to the cord's thickness, is at least 35 cN / tex. In one embodiment, the tensile strength of a guide cord according to the invention, relative to the cord's thickness, is at least 38 cN / tex. In one embodiment, the tensile strength of a guide cord according to the invention, relative to the cord's thickness, is at least 41 cN / tex. In one embodiment, the tensile strength of a guide cord according to the invention, relative to the cord's thickness, is at least 44 cN / tex. In one embodiment, the tensile strength of a guide cord according to the invention, relative to the cord's thickness, is at least 46 cN / tex.Since the tensile strength of the prior art guide cords, relative to the cord thickness, is a maximum of 37 cN / tex, this results in an increase of at least 2.5% in the tensile strength relative to the cord thickness in every case. All specifications for tensile strength relative to the cord thickness refer to measurements according to DIN EN ISO 2062 with a clamping length of 500 mm in standard climate conditions according to DIN EN ISO 139-1:2005. The fineness of the cord is determined according to DIN 53830 Part 3. The guide cord typically has a fineness of at least 3000 dtex. In one embodiment, the guide cord has a fineness of at least 5000 dtex, 6000 dtex, 8000 dtex, 10000 dtex, or 12000 dtex.

[0029] The guide cord typically has a maximum fineness of 45,000 dtex. In one embodiment, the guide cord has a maximum fineness of 30,000 dtex, 16,000 dtex, 10,000 dtex, or 8,000 dtex.

[0030] In one embodiment, the guide cord comprises at least one yarn, preferably two or more yarns, e.g. three, four, five, ten or twenty cellulose multifilament yarns.

[0031] To improve usability, the guide wire can be impregnated with a stiffening agent. To ensure that the plant remains and the guide wire can be used together as fertilizer or mulch, a biodegradable impregnating agent is advantageously used. This could include, for example, polysaccharides, starch, a starch derivative such as paste, polyvinyl alcohol, polycaprolactone, polybutylene succinate, polylactide, a plant or animal wax such as carnauba wax, sugar cane wax, lanolin, candelilla wax, carbomethylcellulose (CMC), or beeswax, or a plant or animal resin such as rosin or shellac, or fats or oils. Other biodegradable materials such as natural latex, linseed oil varnish, or chitosan can also be used.The impregnating agent should be able to stiffen the support cord, but at the same time, it should not impair the coiling capability of the support cord, which is typically sold and transported spooled. Likewise, it should not impair the possibility of winding the support cord onto winding hooks (also known to those skilled in the art as "tomato hooks") as described in the application. Increased resistance to rot is particularly advantageous for crops grown in soil rather than sterile nutrient solutions, which is often the case with peppers and eggplants, for example. The choice of impregnating agent can influence the biodegradability of the support cord by slowing it down.

[0032] If the impregnating agent is a substance that reinforces or stiffens the structure of the guide cord, it can also be used to stabilize the cross-section of the guide cord in a desired shape. In one embodiment, for example, the impregnated guide cord has a rectangular or ribbon-shaped cross-section, which significantly reduces the tendency of the guide cord to cut into plant stems, shoots, or tendrils compared to twisted guide cords. A ribbon-shaped cross-section is a rectangular cross-section in which the smaller dimension of the rectangle is at least 20 times smaller than the larger dimension of the rectangle.

[0033] In addition to a stiffening impregnating agent, the guide wire according to the present application can also be provided with further finishing materials. These include, for example, dyes, UV protection, or antioxidants, but also substances that have a direct or indirect effect on the plant being trained on the guide wire. For example, impregnation with a fertilizer solution is conceivable, the components of which are gradually released into the soil during the use of the guide wire or which are mobilized during the composting process. Furthermore, the guide wire according to the invention can also be equipped with biocides that protect the plant from pest infestation. Possible biocides (EU 528 / 2012, EC 1107 / 2009) are, for example, insecticides or fungicides, the latter of which can also protect the guide wire from rot. Impregnation with repellents that keep away harmful insects is also conceivable. The incorporation of sensors (e.g.,(for weight control, local moisture or nutrient control), LED light sources or electrically conductive threads in the guide cord are possible.

[0034] The desired substances can also be applied to the guide cord using spraying, printing, dipping or extrusion methods, or spun directly into the yarn.

[0035] When cultivating some types of climbing plants, it can be advantageous for yield if the support cord is retensioned from time to time, thus stretching the climbing plant. With prior art support cords, this is usually done manually. In contrast, the support cord according to the invention offers the possibility of being designed to retension itself automatically. Viscose fibers exhibit significant wet shrinkage and reduce their length upon contact with water or humid air. In this way, viscose fiber support cords in greenhouses can be retensioned, for example, by targeted humidification using drip or sprinkler systems, without the need for manual labor. The degree of wet shrinkage can be controlled by the process parameters during the production of the multifilament material.

[0036] Furthermore, impregnation can significantly reduce the wet shrinkage of the guide cord. For this purpose, the impregnating agent, consisting of an aqueous solution, suspension, or emulsion, is applied to the guide cord, with the water triggering the wet shrinkage. If the guide cord is then dried without tension, its original length is not restored, and the shrunken state is effectively frozen as the impregnating agent dries.

[0037] The invention further relates to a method for producing a guide cord comprising the steps of laying down at least two cellulose multifilament yarns, guiding the multifilament yarn through a swirling nozzle and swirling the filaments of the multifilament yarn together.

[0038] In one embodiment, at least 150, at least 300, at least 450, at least 500, at least 600, or at least 700 standard liters of air per minute are passed through the swirl nozzle. In another embodiment, at most 400, at most 450, at most 500, at most 600, at most 700, at most 800, or at most 900 standard liters of air per minute are passed through the swirl nozzle.

[0039] In one embodiment, the air pressure in the swirl nozzle is at least 2 bar, at least 2.5 bar, at least 3 bar, at least 3.5 bar, at least 4 bar, or at least 5 bar. In another embodiment, the air pressure in the swirl nozzle is at most 3 bar, at most 3.5 bar, at most 4 bar, at most 4.5 bar, at most 5 bar, at most 6 bar, at most 7 bar, at most 8 bar, or at most 10 bar.

[0040] In one embodiment, the guide cord comprises at least one yarn, preferably two or more yarns, e.g. three, four, five, ten or twenty cellulose multifilament yarns.

Claims

guide cord Patent claims:

1. Guide cord, wherein the guide cord is biodegradable and contains cellulosic yarns, characterized in that the cellulosic yarns are multifilament yarns which are irregularly intertwined locally or continuously and that the guide cord is fluffed up.

2. Guide cord according to one of the preceding claims, wherein the guide cord is provided with an impregnating agent.

3. Guide cord according to claim 2, wherein the stiffening impregnating agent is polysaccharide, starch, a starch derivative, polyvinyl alcohol, polycaprolactone, polylactide, polybutylene succinate, natural latex, chitosan, fats, oils, linseed oil varnish, a vegetable or animal wax such as carnauba wax, sugar cane wax, candelilla wax, carboxymethylcellulose or beeswax, or a vegetable or animal resin such as rosin or shellac.

4. Guide cord according to one of the preceding claims, wherein the guide cord has a tensile strength of at least 30 cN / tex relative to the thickness of the cord.

5. Guide cord according to one of the preceding claims, wherein the guide cord is impregnated with one or more fertilizers, insecticides, fungicides or repellents.

6. Guide cord according to one or more of the preceding claims, wherein the guide cord has a rectangular or ribbon-like cross-section.

7. Method for manufacturing a guide cord according to one of the preceding claims, comprising the steps a. Feeding one or more cellulose multifilament yarns, b. Guiding the cellulose multifilament yarns through a vortex nozzle, Intertwining of the individual filaments of the multifilament game.

8. Use of a guide cord according to one or more of claims 1 to 6 or a guide cord produced according to the method in claim 7 in greenhouse crops, preferably in the cultivation of tomatoes, peppers, aubergines, zucchini, raspberries, beans or cucumbers.