DE19800842A1 - Biodegradable synthetic yarn material for use as cords in agriculture - Google Patents

Abstract

The synthetic yarn material (1) is a monofilament of a biologically degradable polyolefin. The total degrading time is controlled. The outer surface is roughened, and it is drawn to increase the tensile strength using a variable drawing action. The yarn (1) material is a biologically degradable high density or low density modified polyethylene (HDPE, LDPE). The material has a higher shear strength than ST 37 wire. The synthetic yarn (1) has a circular crosssection, with projecting ribs (4) or profiles at the circumference. The cross section can also be oval, or follow a suitable curve, or it can be quadrilateral or other polygon crosssection shape.

Description

The patent claims are based on a plastic thread.

The use of such plastic threads according to the invention is intended below exemplified in hop cultivation, but the use is also also in other areas, e.g. B. viticulture, construction or Packaging industry possible.

In hop growing, iron wires are used as climbing aids for hop plants used. The plant can grow upwards on the wires and thus can reach the desired heights when hopping up to about seven meters.

The wires are connected to a cross wire in the hop garden knotted and in the ground in the immediate vicinity of the hop plant stuck. The wire is harvested by hand or by machine when the hops are harvested cut off just below the ground with the hop plant and above also demolished with the hop plant.

In the hop-picking machine, the wire is cut together with the plant remains of the hop plant is chopped up and left to rot or rust Fields spent.

Before the hop plant starts to sprout again next spring, a new hop wire for each hop plant as described above appropriate.

The hop wires are currently made of iron, usually ST 37, and have a round cross-section with a diameter between 1.1 and 1.5 mm. The hop plant needs a certain surface roughness on the wire surface in order to hold on to the wire well. With conventional iron wire, this surface roughness results from the manufacturing process and from the resulting rust film.

The conventional iron wire has major disadvantages.

A first disadvantage is its very high weight. A larger hop farmer owns approx. 100,000 hop plants, d. H. he has to reattach 100,000 wires every year. Here he has to carry and carry enormous weights.

Another disadvantage is the relatively high price. Another disadvantage is that the Chopping the wire occurs a very high wear on the chopping knives. A the so-called "hop spikes" are a particular disadvantage. If the Hop farmer with the tractor and wagon the chopped material with the approx. 2 to 5 cm long pieces of iron wire from his farm on the fields, it comes regularly that such "hop spikes" fall on the street. When driving over  These "hop spikes" with the car then drill into the tires and lead to high damage.

Another major disadvantage is the accumulation of environmentally harmful substances in the ground.

The same applies to other areas of application.

Plastic threads are often used to remedy the problems described Monofilament or multifilament threads have been described. None of the described Threads have been successful in practice. This is because with all Plastic threads only one of the variety of problems described was solved more or less well, but the others remained.

So z. B. in DE 24 50 062 B2 a monofilament thread made of plastic described. This thread has an extremely disadvantageous mirror smooth Surface and can only be used in conjunction with a special hook Find. The mirror-smooth surface prevents knots from locking themselves and practice has shown that tendrils cannot find a foothold. In addition, the strength of the thread is unsatisfactory.

DE 34 17 543 A1 describes a monofilament for bringing up hops described. Here, however, a highly environmentally harmful mixture is formed Plastics used, namely polyolefins with styrene polymer. From styrene is known to be suspected of causing cancer.

In DE-GM 73 00 375 a common multifilament cord is used as Hop line is described. This cord does not loosen any of the above problems described and has yet another problem, she wraps around the chopping knife when the plant remains are chopped and blocks the entire chopper.

DE-OS 22 62 480 describes a wire for agricultural purposes. He should consist of polyolefins or related polymers and is said to have a pimple-like surface. This alone is not enough for the above To solve problems. In addition, the pimples are a problem because they are can press into the plant cell structure and damage the plants.

EP 0 536 009 A1 only describes that plastic products degrade through chemical attacks or photo degradation.

DE-GM 94 13 194.5 describes a seed mat, some of which are not detailed described decomposing materials.

DE 44 40 858 A1 describes biodegradable polyesters and their Manufacturing described what is not a solution to the above problems represents.

The invention has therefore set itself the task of a plastic thread To make available that avoids all these disadvantages.  

The solution to this problem is characterized in that it is a monofilament is made of a biodegradable polyolefin, the time until complete degradation is controllable, it is roughened on the surface, it is used Strength increase is stretched and the increase in strength by varying the Stretching is adjustable.

Particularly advantageous embodiments of the invention are in the subclaims described.

With the plastic threads according to the invention, all of the above are described Disadvantages of iron wires or multifilament threads safely avoided.

The ecological aspect is particularly noteworthy.

Due to the iron wires or non-degradable plastic threads, one becomes unnatural and harmful enrichment of the soil with z. B. iron and Iron compounds or other pollutants caused.

In the plastic thread according to the invention made of biodegradable Plastic disintegrates after a certain, definable time and becomes plastic under composting conditions by the bacteria and microbes in the soil converted natural excretion products, so that even one more natural fertilization is achieved.

The time it takes for the plastic thread according to the invention to completely break down is adjustable within limits, d. H. the plastic thread can be defined in its Dismantling time can be set for each individual application.

Variations in the stretching process can also affect the tensile strength on everyone special application.

The plastic thread according to the invention is both for manual and suitable for mechanical knotting.

In the drawing, only possible exemplary configurations of the plastic Thread shown.

Show it:

Fig. 1 shows a cross section of a plastic thread made of a stretched biodegradable plastic

Fig. 2 shows a cross section of another plastic thread made of a stretched biodegradable plastic

Fig. 3 shows a longitudinal section of another plastic thread made of a stretched biodegradable plastic.

The plastic threads are produced in the extrusion process. Then here by the geometry of the extrusion tool and the calibration or by downstream profiling devices the corresponding plastic thread Geometry or surface quality can be given.

A necessary surface roughness can be determined by chemical, physical or mechanical processes can be achieved.  

The increase in strength can be achieved by cold or warm stretching processes. Depending on the desired strength, the stretching process is one or more stages, cold or done warm.

Fig. 1 shows a plastic thread 1 , which is round in cross section, but has outwardly directed webs 4 .

Fig. 2 shows a further plastic thread 1 in cross section, it can be seen here that the surface has been provided with a certain roughness 5 .

FIG. 3 shows another plastic thread 1 in longitudinal section. A profile 6 of the surface can be seen here.

Both with the webs 4 and with the roughness 5 and also with the profiling 6 one achieves that z. B. a hop plant on the plastic thread 1 finds an excellent hold.

Self-locking of a knot is also ensured.

Claims (12)

1. Plastic thread ( 1 ), characterized in that

• - it is a monofilament,
• - it consists of a biodegradable polyolefin,
• - the time until complete dismantling is controllable,
• - it is roughened on the surface,
• - he is stretched to increase strength,
• - The increase in strength can be adjusted by varying the stretching.

2. Plastic thread ( 1 ) according to claim 1, characterized in that it consists of biodegradable modified PE-HD. 3. Plastic thread ( 1 ) according to one or more of the preceding claims, characterized in that it consists of biodegradable modified PE-LD. 4. plastic thread ( 1 ) according to claim 1, characterized in that it consists of biodegradable modified PP. 5. Plastic thread ( 1 ) according to one or more of the preceding claims, characterized in that it has a higher tensile strength than wires made of ST 37 . 6. Plastic thread ( 1 ) according to one or more of the preceding claims, characterized in that it is round in cross section. 7. plastic thread ( 1 ) according to one or more of the preceding claims, characterized in that it is round in cross section and is equipped with webs ( 4 ) on the circumference. 8. plastic thread ( 1 ) according to one or more of the preceding claims, characterized in that it has a profile ( 6 ) on its surface. 9. plastic thread ( 1 ) according to one or more of the preceding claims, characterized in that it is oval in cross section. 10. Plastic thread ( 1 ) according to one or more of the preceding claims, characterized in that it follows any curve in cross section. 11. Plastic thread ( 1 ) according to one or more of the preceding claims, characterized in that it is square in cross section. 12. Plastic thread ( 1 ) according to one or more of the preceding claims, characterized in that it is polygonal in cross section.