ORGANIC BASED EMULSIONS FOR SUN FILTER APPLICATIONS

Abstract

The present invention refers to an agricultural composition for providing UV-A and/or UV-B protection to plants and parts thereof, the composition comprising at least one wax, at least one lignin, at least one emulsifier, water, optionally calcium carbonate, and optionally a solvent, wherein the ratio of wax:lignin in the composition is from 100:1 to 100:200 based on the dry weight of the wax and the lignin. Furthermore, the present invention refers to the use of such an agricultural composition for UV-A and/or UV-B protection of plants and parts thereof as well as to the use of the combination of at least one wax and at least one lignin as UV-A and/or UV-B protecting agent, wherein the ratio of wax:lignin is from 100:1 to 100:200 based on the dry weight of the wax and the lignin.

Claims

1. An agricultural composition for providing UV-A and/or UV-B protection to plants and parts thereof, the composition comprising: at least one wax; at least one lignin; at least one emulsifier; water; optionally calcium carbonate; and optionally a solvent; wherein the ratio of wax:lignin in the composition is from 100:1 to 100:200 based on the dry weight of the wax and the lignin.

2. The agricultural composition according to claim 1, wherein the composition consists of: at least one wax; at least one lignin; at least one emulsifier; water; optionally calcium carbonate; and optionally a solvent.

3. The agricultural composition according to claim 1, wherein the ratio of wax:lignin in the composition is from 100:5 to 100:180, preferably from 100:10 to 100:150, and most preferably from 100:30 to 100:100 based on the dry weight of the wax and the lignin.

4. The agricultural composition according to claim 1, wherein the at least one wax is selected from the group consisting of carnauba wax, bees wax, paraffin wax, shellac wax, candelilla wax, ouricury wax, sugar-cane wax, soy wax, bayberry wax, petroleum waxes, laurel wax, rice bran wax and mixtures thereof and preferably is carnauba wax.

5. The agricultural composition according to claim 1, wherein the at least one lignin is selected from the group consisting of natural lignin, klason lignin, hydrolyzed lignin, milled wood lignin, soda lignin, organosolv lignin, kraft lignin, alkali lignin, sulphonated lignin and mixtures thereof and preferably is sulphonated lignin.

6. The agricultural composition according to claim 1, wherein the at least one emulsifier is selected from the group comprising PEG compounds, PEG-free emulsifier, silicone-based emulsifier, silicones, fatty acids and mixtures thereof.

7. The agricultural composition according to claim 1, wherein the at least one wax and the at least on lignin are each present in the composition in an amount from 0.1 to 45 wt.-% based on the total weight of the agricultural composition, preferably in an amount of 0.5 to 40 wt.-%, even more preferably in an amount of 0.8 to 30 wt.-% and most preferably in an amount of 1 to 20 wt.-% based on the total weight of the agricultural composition.

8. The agricultural composition according to claim 1, wherein the at least one emulsifier is present in the composition in an amount from 0.1 to 30 wt.-% based on the total weight of the agricultural composition, preferably in an amount of 1 to 15 wt.-%, and most preferably in an amount of 2 to 10 wt.-%, based on the total weight of the agricultural composition.

9. The agricultural composition according to claim 1, wherein the agricultural composition comprises calcium carbonate, preferably in an amount from 0.1 to 10 wt.-% based on the total weight of the agricultural composition, more preferably in an amount from 0.3 to 3 wt.-%, even more preferably in an amount from 0.5 to 2 wt.-% and most preferably in an amount from 0.8 to 1.5 wt.-% based on the total weight of the agricultural composition.

10. The agricultural composition according to claim 2, wherein the calcium carbonate is selected from the group consisting of ground calcium carbonate (GCC), preferably marble, limestone, chalk and/or nanoGCC, precipitated calcium carbonate (PCC), preferably vaterite, calcite and/or aragonite, and mixtures thereof and most preferably the calcium carbonate is ground calcium carbonate.

11. The agricultural composition according to claim 1, wherein the solvent is present in the agricultural composition, and preferably the ratio of solvent:lignin in the composition is from 5:1 to 100:1, preferably from 10:1 to 20:1, and most preferably from 12:1 to 16:1 based on the dry weight of the solvent and the lignin.

12. The agricultural composition according to claim 1, wherein the at least one lignin is a water-soluble lignin, preferably sulphonated lignin, and no solvent is present in the agricultural composition.

13. The agricultural composition according to claim 1, wherein the composition is in the liquid form.

14. A method of using an agricultural composition according to claims 1 for UV-A and/or UV-B protection of plants and parts thereof, comprising the step of applying the agricultural composition to plants and parts thereof.

15. The method according to claim 14, wherein the plants and parts thereof are fruits, vegetables, trees, seeds, leaves, wood, nuts, crops, crop plants and flowers.

16. A method of using an agricultural composition as a UV-A and/or UV-B protecting agent, comprising the step of applying the agricultural composition to plants and parts thereof, wherein the agricultural composition comprises at least one wax and at least one lignin, and wherein the ratio of wax:lignin is from 100:1 to 100:200 based on the dry weight of the wax and the lignin.

17. The agricultural composition according to claim 2, wherein the ratio of wax:lignin in the composition is from 100:5 to 100:180, preferably from 100:10 to 100:150, and most preferably from 100:30 to 100:100 based on the dry weight of the wax and the lignin.

18. The agricultural composition according to claim 2, wherein the at least one wax and the at least on lignin are each present in the composition in an amount of 1 to 20 wt.-% based on the total weight of the agricultural composition.

19. The agricultural composition according to claim 2, the agricultural composition comprises calcium carbonate in an amount from 0.8 to 1.5 wt.-% based on the total weight of the agricultural composition.

20. The agricultural composition according to claim 2 wherein the at least one lignin is a water-soluble lignin, preferably sulphonated lignin, and no solvent is present in the agricultural composition.

Description

FIGURES

[0182] FIG. 1: Schematic of the absorbance measurement with the sample located inside the integrating sphere.

[0183] FIG. 2: Schematic of the transmittance measurement with the integrating sphere.

[0184] FIG. 3: Absorbance of the agricultural compositions with 0, 0.5, 1.5, 2, 3 and 5 wt.-% lignin.

[0185] FIG. 4: Absorbance of the agricultural compositions as a function of lignin concentration at 300 nm and 360 nm.

[0186] FIG. 5: Transmittance of an agricultural composition comprising only 5 wt.-% wax, only 5 wt.-% lignin, a combination of 5 wt.-% wax and 5 wt.-% lignin and a combination of 5 wt.-%, 5 wt.-% lignin and 1.5 wt.-% calcium carbonate.

EXPERIMENTS

1. Measurement Methods

[0187] In the following, measurement methods implemented in the examples are described.

Transmittance and Absorbance Measurements

[0188] The transmittance and absorbance measurements are carried out with a double beam PerkinElmer Lambda 950 UV/Vis/NIR spectrophotometer equipped with a 150 mm integrating sphere PMT—InGaAs detectors.

[0189] For the absorbance analysis, the tested agricultural compositions are diluted with deionized water in a volume ratio of 1:80. The agricultural compositions are poured in a quartz cuvette with a 1 cm path length and placed with a center mount holder inside the integrating sphere as shown in FIG. 1. This setup allows for simultaneous measurement of both the transmittance (T) and reflectance (R) of the sample, so that the absorbance (A) can be derived as

A=−log(T+R) [0190] in one single measurement.

[0191] Deionized water is used as reference measurement. The spectrophotometer is scanned in the range 280 nm-400 nm in steps of 2 nm. Two replicate samples for each diluted agricultural composition are prepared and measured, and the average absorption spectrum is calculated.

[0192] For the transmittance analysis, the samples are prepared by spraying the agricultural compositions on a quartz plate (50×50×3 mm). The coated plates are let drying for 1 hour in the dark. The as-prepared plates are placed at the entrance of the integrating sphere as shown in FIG. 2. The transmittance measurements are performed in the range 280 nm-400 nm in steps of 2 nm. Four repetitions are performed on each sample at different sample locations obtained by rotating the sample by 90° around the axis of incident light beam. The average transmittance spectrum of the sample is then calculated. Finally, the average transmittance spectra of the samples are normalized to the average transmittance of the bare quartz plate.

Particle Size Distribution

[0193] The weight determined median particle size d50(wt) was measured by the sedimentation method, which is an analysis of sedimentation behaviour in a gravimetric field. The measurement was made with a Sedigraph™ 5100 of Micromeritics Instrument Corporation, USA. The method and the instrument are known to the skilled person and are commonly used to determine particle size distributions of fillers and pigments. The measurement was carried out in an aqueous solution of 0.1 wt.-% Na4P2O7. The samples were dispersed using a high speed stirrer and supersonicated.

2. Materials Used in the Examples

[0194] Wax: Carnauba wax No. 1 yellow (CAS: 8015-86-9), available from Sigma Aldrich under the number 243213-250G

[0195] Lignin: Sodium sulphonated lignin, available from Domsjö Fabriker under the trade name Domsjö Lignin DS 10

[0196] Emulsifier: stearic acid (CAS: 57-11-4) in powder form, available from Sigma Aldrich under the number 54751 and triethanolamine (CAS: 102-71-6) in liquid form, available from Sigma Aldrich under the number T58300-25G

[0197] Water: Distilled water

[0198] Calcium carbonate: Ground calcium carbonate of marble type having a calcium carbonate content of more than 97.5 wt.-%; The ground calcium carbonate has a particles size of less than 2 μm in an amount of 52 to 62 wt.-% and a medium particle diameter d50 in the range of 1.2 to 2.2 μm

3. Tests

[0199] The following agricultural compositions were prepared:

[0200] In a heated bottom flask (95° C.), 11 g of carnauba wax was added and mixed slowly to melt the solid. 5 g of stearic acid was added to the latter, then kept under mixing to solubilize. Afterwards, 5 g of triethanolamine was furtherly added to the mixture and kept for 15 minutes. 180 g of boiling hot water was added to the mixture and kept for 30 minutes. Finally, different amounts of water-soluble lignin were added to the composition such that the composition comprises 0, 0.5, 1.5, 2, 3 or 5 wt.-% of lignin based on the total weight of the agricultural composition. The ratios of the wax to the lignin in these compositions are therefore 100:0, 100:10, 100:30, 100:40, 100:60, and 100:100.

[0201] Optionally, calcium carbonate is added to these compositions under mixing conditions in an amount of 1.5 wt.-%, based on the total weight of the agricultural compositions.

Absorbance Tests 01

[0202] The absorbance of the above prepared agricultural compositions is measured. As can be seen from FIG. 3 the combination of the at least one wax and the at least one lignin in the claimed range leads to an improved absorbance in the UV-A and UV-B range.

Absorbance Test 02

[0203] The absorbance of the above prepared agricultural compositions is calculated from FIG. 3 at 300 nm in the UV-B range and at 360 nm in the UV-A range and shown as a function of the lignin concentration. It can be seen from FIG. 4 that the absorbance increases linearly with increasing concentration of lignin. Therefore, the combination of the at least one wax and the at least one lignin leads to an improved absorbance in the UV-A and UV-B range.

Transmittance Test 01

[0204] The transmittance of three agricultural compositions comprising only wax (5 wt.-%) or only lignin (5 wt.-%) or a combination of wax and lignin (both 5 wt.-%) is measured. As can be seen from FIG. 5, the lower UV-A and UV-B transmittance is achieved with the combination of both wax and lignin. Therefore, such an agricultural composition containing both wax and lignin could be used as a sunscreen with improved performance compared to an agricultural composition containing only wax or only lignin.

[0205] The transmittance of the above prepared agricultural composition comprising a combination of both 5 wt.-% wax and 5 wt.-% lignin and in addition 1.5 wt.-% CaCO3 was also measured. Upon inclusion of CaCO3 in the agricultural composition, the UV-A and UV-B transmittance further decreases.