HU208899B - Process for producing microporous, water-permeable tubes from compositions comprising vulcanized rubber grinds and thermoplastic synthetic materials - Google Patents

Abstract

Microporous, water permeable pipes are prepd from a mix based on reground vulcanized rubber of an average 0.5-2.0 mm particle size to which at least 7% of powdered thermoplastic is added, pref. high pressure low-density polyethylene, as well as 0.1 wt% of a mixt of penta:chloro-thio-phenol and an organic-metal-complex cpd, 0-0.05 wt% rubber and/or plastic additives, as heat light and UV stabilizers and/or fungicides, and bactericides. The mixt is fed into an extruder at 140-200 deg.C, pref. 160-180 deg.C and extruded via a mesh with less than 1 mm apertures. Material leaving the high pressure extrusion head is cooled intensively, resulting in microfissures during contraction due to the dissimilarity in the coefficients of linear expansion of the two materials.

Description

Scope of the description: 4 pages (including 1 page figure)

EN 208,899 Β

The present invention relates to a method for producing microporous water permeable tubes from a composition comprising vulcanised rubber and thermoplastic.

The production of porous tubes for irrigation plant cultivation is accomplished in a variety of known ways.

No. 77 89 172. according to Japanese Kokai (26.7.1977) (CA 8720 2615 m), a porous plastic tube made of polyethylene or ethylene-vinyl acetate copolymer with a softening point higher than 100 μm, and an inorganic or organic (polymer) powder of less than 100 μm; Extraction of an inorganic powder with a diameter of less than 10 μm and containing H ₂ O yields a porous product. Thus, the above raw material, cellulose and CaSO ₄ -2H ₂ O, are extruded at 130 ° C to form a water and gas permeable tube.

Kokai Tokkio Koko IP 58 167 628 (03.03.1983) (CA 10010463 e), 100 parts by weight of a 30 mesh (0.5 mm) milled tire waste, 50-60 parts by weight of polyethylene pellet and 3 parts by weight of sodium hydrogen carbonate. the mixture is extruded at 120-150 ° C to form a porous tube.

No. 1 296 545 According to British patent specification, a mixture of poly (methyl methyl acrylate) or PVC press and acrylonitrile-butadiene-styrene copolymer blends 0.5-10% by weight of sodium bicarbonate and sodium carbonate and extruded to give a porous product .

No. 4,177,334. U.S. Pat. No. 4,196,196 discloses a process for producing a microporous tube from poly tetrafluoroethylene.

No. 4,003,408 U.S. Pat. No. 4,013,406 proposes the preparation of an underground irrigation porous tube by blending a regenerated tire regenerate of 70% 30 mesh (0.6 mm) into a 30% high density polyethylene vinyl, acrylonitrile-butadiene-styrene copolymer (ABS), with a mixture of attaclay. Open-cell labyrinths are formed to foam the vapor from the regenerate-absorbed moisture from the extrusion and to release the gases released from the material, and the water permeability of the resulting tube is between 0.3 and 0.7 bar per hour at 1.5-2.5 1 / m.

All of the prior art processes provide porosity for water permeability using some kind of propellant, which may be gas, water vapor, sodium hydrogen carbonate, etc. released from the material during the technology.

The invention is based on the discovery that an amorphous rubber blend with a diameter of 0.5 to 2.0 mm and a high pressure, low density polyethylene blend extruded at 160-180 ° C during extrusion head pressure and then out of the extruder head due to the different linear shrinkage of the two materials , when the pressure is eliminated, they swell differently and, as a result, microcapillaries develop on the contact surfaces of the two materials. In this way, by adding a special decomposition agent, the devulcanized layer formed on the surface of the rubber foam results in adhesion that provides sufficient strength with the low density polyethylene, so that the microcapillaries formed by the head pressure escape do not reduce the strength, and the tube is cooled to the required size within a specified distance and is cooled to the required size, and no larger microbial cracks are achieved.

It is an object of the present invention to vulcanize a rubber granule having an average particle size of 0.52.0 mm by mixing with at least 7 parts by weight of thermoplastic powder, preferably high pressure, low density polyethylene, by adding at least 0.1 parts by weight of disintegrant to pentachlorothiophenol and organic. a mixture of metal complexes, optionally up to 0.5 parts by weight of one or more rubber and / or plastic auxiliaries, preferably heat-light UV stabilizers, and / or a mixture of glycoside and bactericides, and 140-200 ° C It is fed into an extruder C, preferably 160-180 ° C, and extruded using a sieve with a mesh size of less than 1 mm through a high pressure extruder head, and the outlet tube is cooled at a cooling rate of at least 10 ° C / s to form microprises, and we fix them.

The pre-blended material is added directly to the extruder, preferably heated to 160-180 ° C, using a sieve in the extruder head having a hole diameter of less than 1 mm, the outlet tube extending intensively at the head, as mentioned above, at a cooling rate of at least 10 ° C / s. - cooling, followed by continuous cooling of at least 7 m, depending on the diameter of the tube and cooling to room temperature, depending on the wall thickness. The cooled tube is applied to the winding unit by a conveyor-tension conveyor belt. With this method, the formation and fixation of the microcracks in the tube production is achieved.

A further essential feature of the invention is that the surface of the rubber beads passing through the sieve with a diameter of up to 1 mm inserted into the extruder head is decompensated due to the friction energy and in the presence of the decomposition agent, and the active surfaces thus formed are more strongly bonded to the thermoplastic plastic. This bond strength ensures that larger cracks do not occur in the microcracks. Tool design ensures high head pressure; leaving the head, the two-component material swells to varying degrees, ensuring microbial cracking. Cooling of the material coming out of the tool to fix the formed micro-cracks to the outer diameter of the tube

Start less than 5 times.

The extruder head die in a high pressure tube is cooled in the cold water stream when the tool is left out, and is cooled and rolled continuously in a refrigerator of sufficient length to reduce the pressure caused by the drop of the tool and the different linear shrinkage.

A possible embodiment of the method according to the invention is illustrated by the figure, in which Figure 1 shows the technological sequence of the method.

Thus, Figure 1 illustrates the process operation when the tubular materials and additives are in powder form, allowing mixing in a simple powder mixer.

Measurement of the balance 2 from the storage tanks 1

After mixing the ingredients in the quick mixer. The vulcanized rubber mortar - thermoplastic system is added directly or after a rest to an extruder 4 preheated to 160170 ° C. The pipe-forming process occurs at 160-180 ° C in the extruder head 5, the formation of the microcracks occurs during the passage through the water flow. After cooling to room temperature, the tube containing the microcracks is transported to the roller 10 by means of the conveyor 9 and the winder 10, and wound every 100,200 meters.

The following examples illustrate the composition of the composition used in the process of the present invention

without limiting the invention to the examples. Example 1 85.01% 800 µm average grain size, 14.91% low density polyethylene powder 0.11% 100.01% pentachlorothiophenol and its metal complex as its zinc or copper salt. Example 2 79.41% An average grain size of less than 1000 mm, 0.11% pentachlorothiophenol and its metal complex as its zinc or copper salt, 20.01% low density polyethylene powder 0.11% Irganox 1010 Ciba-Geigy, Oxidative Anti-Aging, 0.11% Irganox PS 800 Ciba-Geigy, Oxidative Ozone, Heat, Aging & Anti-Fatigue 0:31% 100.01% stabilizer, preferably 2,4-dihydroxybenzophenone. Example 3 91.61% Average rubber particle size between 800 and 1400 pm 0.11% pentachlorothiophenol and its metal complex as its zinc or copper salt, 8.01% low density polyethylene powder 0,3t% UV stabilizer

preferably 2,4-dihydroxybenzophenone.

100.01%

Addition of the mixtures was carried out in an extruder heated to 170 ° C, and after the extrusion the cooling tube was cooled at a cooling rate of 12 ° C / s.

According to the present invention, the composition may be thermoplastic as a binder: low density polyethylene, high density polyethylene, linear polyethylene, polypropylene, ethylene vinyl acetate copolymer, polyvinylacetate, ethylene-ethyl acetate copolymer, polystyrene, and the like. Vulcanized rubber strips are selected from the group consisting of grinding of natural and butadiene-styrene rubber-based vulcanised rubber with a rubber and non-selective rubber strip.

It can be used as an auxiliary material for the rubber and plastics industry, e.g. a mixture of phenol, amine or sulfur-containing heat stabilizers, surfactants, lubricants, fungicides, bactericides, pentachlorothiophenol and organic metal complex.

The present invention allows a low density polyethylene to be used as a binder to produce a leaking irrigation tube containing microbes from a surface-activated rubber foam. The surface-activation of the rubber foam allows the use of a high-grade, less energy-consuming, 1.0 mm (16 mesh) rubber foam instead of the high-grade 0.5 mm (BSS 410, 30 mesh) rubber foam used in the known processes and as a binder. reduce the amount of polyethylene used in the process. In addition to the degradation pentachlorothiophenol and the organometallic complex, the degradation of the iron bacteria in the water is prevented by degradation by the chlorine content contained therein, and the metal complex also ensures that it cannot develop during the application of the surface.

The method according to the invention makes it possible to form more uniform and smaller microchrops than known. The leakage rate of known processes, which is strongly reduced (0.3-065 bar) per hour at 1.5-2.5 l / m, requires internal water pressure. Our process also provides the required leakage rate at an internal water pressure of 0.8-1.5 bar.

Claims (3)

PATENT CLAIMS CLAIMS 1. A method for producing microporous water-permeable tubes, wherein the tube is extruded from at least 7 parts by weight of a thermoplastic plastic powder, preferably high-pressure low-density polyethylene powder, of vulcanized rubber powder having an average particle size of 0.5 to 2.0 mm. , 1 part by weight of a disintegrant, preferably a mixture of pentachlorothiophenol and an organometallic complex, optionally up to 0.5 parts by weight of one or more auxiliaries for rubber and / or plastics, preferably from heat-light UV stabilizers and / or fungicidal, bactericidal substances preparing a mixture; and feeding it to an extruder heated to 140-200 ° C, preferably 160-180 ° C; and extruding it through a high pressure extruder head using a mesh of less than 1 mm mesh; cooling the outlet tube at an intense cooling rate of at least 10 ° C / s. Method according to claim 1, characterized in that the intensive cooling is applied at a distance less than 5 times the outer diameter of the pipe from the exit of the tool. The process according to claim 1, wherein the rubber powder is wholly vulcanized rubber, the raw material of which is natural rubber and / or butadiene-styrene, and the granulate has an average particle size greater than 0.5 mm.