Plant protective cover
This invention relates to a plant protective cover of a translucent polymeric material including at least one transmission spectrum modifier for minimizing the transmission in the ultraviolet range up to 350 nm; and for adjusting the transmission in the visible light range between 350 nm and 750 nm in accordance with photosynthetic and photomorphogenic requirements of plants to be cultivated underneath the plant protective cover, to enhance the growth conditions of such plants. The cover further includes a transmission spectrum modifier for minimizing the transmission in the infrared range above 750 nm. The transmission in the visible light range between 350 nm and 750 nm is adjusted by decreasing the transmitted green and yellow wavelengths and by changing the ratio of blue to red wavelengths transmitted towards a 2:3 ratio. The cover optimises growing conditions for plants cultivated underneath the cover thus providing relatively enhanced plant growth and performance.
1. A plant protective cover comprising
a translucent polymeric material,
a first transmission spectrum modifier in the material for minimizing the transmission in the ultraviolet range up to 350 nm, and
a second transmission spectrum modifier in the material in the form of chromophtal red BRN to adjust the transmission in the visible light range between 350 nm and 750 nm of natural light irradiation passing through the cover, in accordance with photosynthetic and photomorphogenic requirements of plants to be cultivated underneath the plant protective cover, to enhance the growth conditions of such plants, by decreasing the transmitted green and yellow wavelengths and by changing the ratio of blue to red wavelengths transmitted to a 2:3 ratio, so as to increase the level of transmission of the red wavelength relative to the level of transmission thereof in the absence of the second transmission spectrum modifier.
2. A plant protective cover according to claim 1 , wherein the material includes between 0.05 and 2.0% on a mass per mass basis of the transmission spectrum modifier in the form of chromophtal red BRN.
3. A plant protective cover as claimed in claim 1 or 2 , which includes in the material at least one substance selected from the group consisting of between 0.1 and 2.0% of a phosphite antioxidant on a mass per mass basis, between 0.1 and 2.0% of a hindered phenolic antioxidant and a pre-irradiated linear low-density polyethylene.
4. A plant protective cover as claimed in claim 3 , wherein the material of the plant protective cover includes on a mass per mass basis any one or more additives selected from the group consisting of 2.0% of a calcined clay IR absorber, 0.3% of a first hindered amine light stabilizer in the form of dimethyl succinate .w/ 4-hydroxy-2,2,6,6-tetramethyl-1 piperidine ethanol, 0.3% of a second hindered amine light stabilizer in the form of poly((6-((1,1,3,3-tetramethylbutyl)amino)-s-triazine-2,4dijil)(2,2,6,6-tetramethyl-4-piperidyl)imino)hexamethylene(2,2,6,6-tetramethyl-4-piperidyl)imino))), 0.4% of a phosphite antioxidant in the form of tris(2,4-di-t-butylphenyl)phosphite, 0.2% of a phenolic antioxidant stabilizer in the form of 1,3,5-trimethyl-2,4,6-tris(3,5-ditert-butyl-4-hydroxybenzyl)benzene, 0.2% of a hindered phenolic antioxidant in the form of tetrakismethylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane and 2.0% of an IR absorber in the form of calcium carbonate (52%), magnesium carbonate (42%), silica (5%) and aluminium hydroxide.
5. A plant protective cover as claimed in claim 1 or 2 , wherein the material of the plant protective cover includes up to 95% on a mass per mass basis of a radiation-pre-crosslinked linear low-density polyethylene having a melt flow index (MFI) of 2160 g/10 min at 190° C.
6. A plant protective cover as claimed in claim 1 or 2 , wherein the cover is produced in a form selected from the group consisting of a mono film, a multi-layer laminate film, a woven net and a knitted net.
7. A plant protective cover as claimed in claim 6 , wherein the cover is in the form of a woven net or a knitted net and the polymeric material is selected from the group consisting of fibrous polyethylenes, polyamides and polyesters.
8. A method of manufacturing a plant protective cover comprising the steps of:
providing a translucent polymeric material;
incorporating in the material a first transmission spectrum modifier for minimizing the transmission in the ultraviolet range up to 350 nm; and
incorporating in the material a second transmission spectrum modifier in the form of chromophtal red BRN to adjust the transmission in the visible light range between 350 nm and 750 nm of natural light irradiation passing through the cover, in accordance with photosynthetic and photomorphogenic requirements of plants to be cultivated underneath the plant protective cover, to enhance the growth conditions of such plants, by decreasing the transmitted green and yellow wavelengths, and by changing the ratio of blue to red wavelengths transmitted to a 2:3 ratio, so as to increase the level of transmission of the red wavelength relative to the level of transmission thereof in the absence of the second transmission spectrum modifier.
9. A method as claimed in claim 8 , wherein the step of incorporating in the material a second transmission spectrum modifier includes the step of incorporating in the material between 0.05 and 2.0% on a mass per mass basis of the spectrum modifier in the form of chromophtal red BRN.
10. A method as claimed in claim 8 or 9 , including the step of including in the material at least one substance selected from the group consisting of between 0.1 and 2.0% of a phosphite antioxidant on a mass per mass basis, between 0.1 and 2.0% of a hindered phenolic antioxidant and a pre-irradiated linear low-density polyethylene.
11. A method as claimed in claim 10 , including the step of including in the material, on a mass per mass, any one or more additives selected from the group consisting of 2.0% of a calcined clay IR absorber, 0.3% of a first hindered amine light stabilizer in the form of dimethyl succinate .w/ 4-hydroxy-2,2,6,6-tetramethyl-1 piperidine ethanol, 0.3% of a second hindered amine light stabilizer in the form of poly((6-((1,1,3,3-tetramethylbutyl)amino)-s-triazine-2,4dijil)(2,2,6,6-tetramethyl-4-piperidyl)imino)hexamethylene(2,2,6,6-tetramethyl-4-piperidyl)imino))), 0.4% of a phosphite antioxidant in the form of tris(2,4-di-t-butylphenyl)phosphite, 0.2% of a phenolic antioxidant stabilizer in the form of 1,3,5-trimethyl-2,4,6-tris(3,5-ditert-butyl-4-hydroxybenzyl)benzene, 0.2% of a hindered phenolic antioxidant in the form of tetrakismethylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)methane, and 2.0% of an IR absorber in the form of calcium carbonate (52%), magnesium carbonate (42%), silica (5%) and aluminium hydroxide.
12. A method as claimed in claim 8 , wherein the step of providing the translucent polymeric material includes the step of providing a material that includes up to 95% on a mass per mass basis of a radiation pre-irradiated linear low-density polyethylene having a melt flow index (MFI) of 2160 g/10 min at 190° C.
13. A method as claimed in claim 8 , wherein the step of providing the translucent polymeric material includes the step of incorporating the transmission spectrum modifiers in one or more films extruded in a form selected from the group consisting of a mono film, a multi-layer laminate film, a woven net and a knitted net.
14. A method as claimed in claim 8 , wherein the cover is in the form of a woven net or a knitted net, and the polymeric material is selected from the group consisting of fibrous polyethylenes, polyamides and polyesters.