MULTILAYER WATER DISPERSIBLE FILM HAVING IMPROVED GERMINATION OF SEEDS AND SOIL FERTILITY

Abstract

This invention relates to water-soluble/dispersible film system with embedded/entrapped water dispersible materials. Said invention discloses water dispersible film system with crop and vegetables seed strip with embedded/entrapped therein such as to provide precise and desired release of actives ingredients there from and its method of manufacturing for diverse applications, in which a variety of substances such as Fertilizers, Micronutrients, Organic fertilizer, Plant growth hormones, Bio-pesticides, Bioinsecticides, Bio fungicide, Organic Soil Conditioners, Plant growth promoter, Neem pesticides, Humicacid, Weed control (herbicide, preemergence herbicide) including treatments for the removal of dormancy. The invention further discloses novel online and offline process for the manufacture of such multi layered water dispersible film with or without liners and of desired shapes to selectively entrap interacting/non-interacting materials and their combinations.

Claims

1. A composite, bio-degradable agricultural film which comprises: a) a first layer formed from a water-soluble resin and at least one releasable form of nitrogen admixed therein and at least one releasable plant nutrient in addition to nitrogen for providing an initial amount of nutrients to a plant during the germination stage and early emergent stage, b) a second layer formed as an adherent coating on said first layer, said second layer comprising a Physical blend of water-soluble synthetic PVOH and PVAc water resisting resin having an average molecular weight which is greater than the average molecular weight of the water soluble synthetic resin in said first layer and at least one releasable form of nitrogen admixed therein, and a water resistant polymer to retard the degradation rate of said second layer and to slow the rate of release of said nitrogen so that said second layer provides needed nutrients to a plant during the later stage of its growth.

2. A composite, degradable, agricultural film as claimed in claim 1 in which the water-soluble synthetic resin in said first layer is a polyvinyl alcohol having an average molecular weight within the range of about 15,000 and about 72,000, and the water-soluble synthetic resin in said second layer is a polyvinyl alcohol having an average molecular weight within the range of about 49,000 and 100,000 and wherein the water-resistant polymer in said second layer is a polyvinyl acetate having an average molecular weight within the range of about 45,000 to about 140,000.

3. A multilayer bio degradable composite, agricultural film which comprises: (a) a first layer formed from a water-soluble synthetic resin and at least one releasable form of nitrogen admixed therein and at least one releasable plant nutrient in addition to nitrogen for providing an initial amount of nutrients to a plant during the preemergent and early emergent stage; (b) a second layer formed as an adherent coating on said first layer, said second layer comprising a water-soluble synthetic resin having an average molecular weight which is greater than the average molecular weight of the water soluble synthetic resin in said first layer and at least one releasable form of nitrogen admixed therein, for providing the nutrients during the growth stage of the plant; and (c) a third layer formed as an adherent coating on said second layer, said third layer comprising a water-soluble synthetic resin having an average molecular weight which is less than the average molecular weight of the water soluble synthetic resin in said second layer.

4. A multilayer bio degradable composite, degradable, agricultural film, as claimed in claim 3 in which said Second layer includes at least one releasable plant nutrient in addition to nitrogen.

5. A multilayer bio degradable composite, degradable, agricultural film, as claimed in claim 4 in which said top layer includes at least one releasable plant nutrient in addition to nitrogen.

6. A multilayer bio degradable composite, degradable, agricultural film, as claimed in claim 3 in which said second layer includes a blend of water soluble and water-resistant polymer to retard the degradation rate of said second layer.

7. A multilayer bio degradable composite, degradable, agricultural film, as claimed in claim 6 in which said water-soluble resin in each of said layers is polyvinyl alcohol.

8. A multilayer bio degradable composite, degradable, agricultural film, as claimed in claim 7 in which the average molecular weight of the polyvinyl alcohol in said first layer ranges from about 15,000 to about 22,000.

9. A multilayer bio degradable composite, degradable, agricultural film, as claimed in claim 8 in which the average molecular weight of the polyvinyl alcohol in said second layer ranges from about 22,000 to about 72,000.

10. A multilayer bio degradable composite, degradable, agricultural film, as claimed in claim 9 in which said average molecular weight of the polyvinyl alcohol in said third layer ranges from about 72,000 to about 95,000.

11. A multilayer bio degradable composite, degradable, agricultural film, as claimed in claim 3 in which said water-resistant polymer is polyvinyl acetate.

12. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 6 in which said water-resistant polymer is polyvinyl acetate and in which the source of nitrogen is a urea formaldehyde condensate with a formaldehyde to urea ratio of about 1:2.

13. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 3 in which said first layer includes a source of phosphorous and potassium.

14. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 13 in which said source of nitrogen is selected from the group consisting of urea and urea-formaldehyde poly condensates.

15. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 14 in which said source of nitrogen is urea and in which said first layer includes a nitrification inhibitor.

16. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 13 in which said plant nutrient in addition to nitrogen is water soluble NPK.

17. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 3 in which said first layer includes starch and a fumigant.

18. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 12 in which said polyvinyl acetate has an average molecular weight within the range of about 45,000 to about 190,000.

19. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 13 in which said second layer includes a urea-formaldehyde poly condensate and di ammonium phosphate. And ammonium sulfate.

20. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 19 in which second layer includes corn starch.

21. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 19 in which said second layer includes an insecticide.

22. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 19 in which said second layer includes a pesticide.

23. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 13 in which said third layer includes a source of phosphorous and potash and soil constructing materials like zinc and ferrous.

24. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 23 in which said third layer includes ethylene-glycol having molecular weight 400 and 6000.

25. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 23 in which said third layer includes propylene glycol.

26. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 23 in which said third layer includes glycerol.

27. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 23 in which said third layer includes wetting agent like non-ionic surfactant e.g. Sodium lauryl sulphate, Triton-X, 100, TRITON-X-114, brig 35 etc.

28. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 23 in which said third layer includes starch.

29. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 23 in which said third layer includes a material selected from the group consisting of insecticides, neem base insecticides, weedicide, pesticides, fungicides and mixtures thereof.

30. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 2 in which said top or first layer includes about 2-5% W/V soluble NPK (19-19-19) (Basfoliar, Germany) has a tensile strength of about (254) Kilograms per square centimeter, and elongation at break of about (116%), about 13.0% moisture, and a thickness of about 20 micron.

31. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 3 in which said second or middle layer includes about 2-5% W/V organic liquid fertilizer has a tensile strength of about (210) Kilograms per square centimeter, and elongation at break of about (45%), about 5.5% moisture, and a thickness of about 20 micron.

32. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 10 in which said core or bottom layer includes about 1-10% W/V corn starch and 0-5% V/V glycerol has a tensile strength of about (264) Kilograms per square centimeter, and elongation at break of about (126%), about 9.35% moisture, and a thickness of about 20 micron.

33. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 1 in which the water-soluble synthetic resin in said first layer is poly vinyl acetate blend with polyvinyl alcohol (10:90 ratio).

34. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 1 in which the water-soluble synthetic resin in said second layer is a poly vinyl acetate blend with polyvinyl alcohol (30:70 ratio).

35. A multilayer biodegradable composite, degradable, agricultural film, as claimed in claim 10 in which said bottom layer includes between about 5-10% W/V starch, 0-8% V/V glycerol, 0-6% V/V propylene glycol, 0-4% V/V poly ethylene glycol 400, 0-5% W/V polyethylene glycol 6000 and 0-2% sodium lauryl sulphate, the thickness of such film may be 15-20 micron and polyvinyl alcohol resins in each of said layers have a degree of hydrolysis ranging from about 86 to about 89%.

36. A method for preparing a clear multilayer multi-nutrients containing biodegradable film which comprises the steps of: (a) forming a blend of PVAc and PVOH solution comprising a water-resistant thermoplastic resin and an organic solvent and nitrogen releasing agents wetting agent and soil constructing agent and plasticizer; (b) casting a film from above said blend (c) drying said film; and (d) forming a blend of water soluble synthetic film-forming resin and water resistance polymer, and at least one nitrogenous constituent which functions as a releasable source of nitrogen and nitrogen releasing agents wetting agent and soil constructing agent and plasticizer (e) coating the dried film resulting from step b with a layer of said aqueous admixture, (f) drying the coating applied in step d; (g) casting the film of solution consisting of polyvinyl alcohol with wetting agent, plasticizer, sealing agent, starch on step e.

37. A method for preparing a clear multi-layer nutrient containing degradable mulch film in accordance with claim 36 wherein the water-resistant thermoplastic resin used in step (a) is selected from the group consisting of polyvinyl acetate, ethylene/acrylic acid copolymer, ethylene/ethyl acrylate copolymer and mixtures thereof.

38. A method for preparing a clear multi-layer nutrient containing degradable film in accordance with claim 37 wherein the water-resistant thermoplastic resin is a polyvinyl acetate having an average molecular weight ranging from about 40,000 to about 190,000.

39. A method for preparing a clear multi-layer multi nutrients containing degradable film in accordance with claim 36 wherein the water-soluble synthetic film forming resins in steps (c) and (j) are selected from the group consisting of blend of polyvinyl alcohol with polyacrylamide and blend of polyvinyl alcohol with polyacrylic acid.

40. A method for preparing a clear multi-layer nutrient containing degradable film in accordance with claim 33 wherein the water-soluble synthetic film forming resins in steps (c), (e) and (g) are polyvinyl alcohol.

41. A method for preparing a clear multi-layer nutrient containing degradable mulch film in accordance with claim 34 wherein the water-resistant thermoplastic resin is a polyvinyl acetate having an average molecular weight ranging from about 40,000 to about 190,000 and wherein the water-soluble synthetic film forming resins in steps (d) and (j) are polyvinyl alcohol having average molecular weights between about 25,000 and about 95,000.

42. A method for preparing a clear multi-layer nutrient containing degradable film in accordance with claim 36 wherein said first, second, and third layer; the poly vinyl alcohol the degree of hydrolysis is ranging from 86-98%; this water-soluble polymeric material may be hot water soluble or cold water soluble depending on the degree of hydrolysis and molecular weight higher the molecular weight having less solubility in cold water.

Description

DESCRIPTION OF DRAWINGS

[0044]

TABLE-US-00001 FIG. 1: Schematic Diagram of Manufacturing Process of Biodegradable Plastic Film FIG. 2: Encapsulation of Seed FIG. 3: Schematic Diagram of Encapsulated Seed with Coated Thread FIG. 4: Schematic Diagram of Sealing of Seed with Coated Thread Using Solution

DETAILED DESCRIPTION OF THE INVENTION

[0045] Some crops need nutrients in three main stages like seed germination, vegetative and flowering for optimal growth and plant production. Such plants need phosphorous and potassium and some nitrogen during the pre-planting or preemergent stage. And during their second stage of growth, i.e., prior to fruiting, such plants require a medium dose of nitrogen and may require some phosphorous and potassium. And then, during the third stage of growth i.e., the flowering or fruiting stage, the plants need a major portion of nitrogen and may need additional amounts of phosphorous and potassium. While other crops such as corn, beans and etc. need nutrients in two main stages. A multi-layer degradable film according to the present invention can be tailored to provide optimal amounts of nutrients during the various stages of plant growth. For example, a preferred embodiment of the present invention includes a water-soluble polymer such as polyvinyl alcohol recommended average molecular weight within the range of about 20,000 to 40,000, Nitrogen, phosphorous and potassium sources such as water soluble NPK, urea, U-F (urea-formaldehyde) condensate product and the like. This layer provides the needed nutrients in the pre-planting or preemergent stage and may also be used to sterilize the soil. The second layer includes a water-soluble polymer such as a polyvinyl alcohol, or methyl cellulose or hydroxyethyl cellulose. However, the water-soluble polymer in the second layer has a higher average molecular weight recommended range from about 40,000 to about 95,000, generally hot water soluble poly vinyl alcohol. The second layer also includes a source of nitrogen such as a urea-formaldehyde condensate product and may include a source of phosphorous and potassium in the form of soluble NPK (19:19:19) and organic liquid fertilizer. The second layer is thin film of water-resistant polymer such as polyvinyl acetate blend with polyvinyl alcohol. This second layer provides the nutrients which are needed during the growth stage of the crop, i.e., prior to fruiting. The third or bottom layer includes a water-soluble polymer such as a polyvinyl alcohol having a relatively low molecular weight and include glycerol, ethylene-glycol having deferent molecular weight, starch, Propylene glycol, wetting agents, insecticides, pesticides, and fungicides. The nutritional multi-layer film as described above is an integral composite that is relatively strong, flexible and which has a high degree of clarity. Other additives can of course be incorporated in the various layers. For example, a nitrification inhibitor such as thiourea, others can be used with urea to slow the rate of release of nitrogen. However, when a urea-formaldehyde condensate is used as a source of nitrogen, a nitrification inhibitor is not usually needed since thiourea-formaldehyde condensate normally provides the desired slow release properties. According to the present preferred embodiment of the invention there are multiple major steps involved in the preparation of a multi-layer controlled release multi nutrients degradable film that can be tailored to meet the needs of a specific crop. For example, the top layer which is the slowest dissolving may be made of 20 to 25% water soluble polymer such as polyvinyl alcohol with a recommended molecular weight ranging from about 72,000 to 100,000 and a degree of hydrolysis ranging from about 97 to about 98%. The top layer also includes from about 2-10% of a water-resistant resin such as poly vinyl acetate in the form of blend with poly vinyl alcohol (30:70 ratio) with various nutrients containing nitrogen (N), phosphorous (P) and potassium (K) salts in form of water soluble NPK (19:19:19) in the range of 0 to 5% w/v. The second layer may contain 20-25% of a water-soluble polyvinyl alcohol with medium molecular weight recommended range from 22,000 to about 72,000, and 10-15% higher molecular weight ranging from 72,000 to 95,000, and about 2-10% of water resistant resin such as polyvinyl acetate and various salts. The second layer includes from 0-5% w/v U-F, 0-4% w/v water soluble NPK and 2-6% v/v organic liquid fertilizer. The third or bottom layer is the fastest dissolving layer and consists of 20 to 25% of low molecular weight polyvinyl alcohol with recommended molecular weights ranging from 15,000 to 22,000 and glycerol, ethylene-glycol having deferent molecular weight, starch, propylene glycol, wetting agents, the source of nitrogen in the above composite film is mainly urea and urea-formaldehyde poly condensates.

[0046] On the other hand, when urea-formaldehyde is added there is no need for nitrification inhibitors to be added because urea-formaldehyde is prepared in such a way as to provide slow release characteristics. In addition, according to our preparation procedure the urea-formaldehyde acts as a binder between the various layers of the composite film. Thus, the urea-formaldehyde used in the present invention is prepared according to the following procedure. A solution of urea is prepared in distilled water of about (120 gm in 500 ml water) and keep solution under continues agitation for 30 min, then add about 30 gm of formaldehyde solution, stir the mixture of 10 min. and then add 1-2 drops of concentrated HCL/H2SO4, stirred the mixture until white precipitation observed. Filter the products and wash with water several time to remove unreacted reactants and acid, dried the reaction product in oven maintain at 70° C. for 2-3 hrs. The molar ration of urea:formaldehyde may be (2:1). Another way is to form condensate product of urea and formaldehyde is dissolve polyvinyl alcohol 25% in water after complete dissolution add urea 10% W/V and formaldehyde solution of 8% V/V, reflux the reaction mixture under continues agitation at 70-80° C. temperature for 30-45 minutes. Stop the heating and agitation before jell formation. Filter the solution and allow to cool at room temperature. The preparation of the multi-layer composite film requires several steps. The film is made by solution casting using conventional casting method (FIG. 1), roller R1 (FIG. 1) is drum-based method. In this method casting solution is poured direct on finished drum surface without any carrier. Casting solution may be pass through two steel rolls having gape adjusting facility on one roll. The coating GSM/Thickness is control by the viscosity of solution and gape between two roll i.e. master roll and finishing roll. The thickness of film varies from about 35-45 micron depending upon the shape and size of the seed. Any coating thickness over the minimum will increase the cost of materials used and of the coating procedure.

[0047] Film Formation:

[0048] All the deferent layer may be cast in single run by using deferent coating head mountain at deferent place on drum as shown in FIG. 1. Inside drum temperature is ranging from 80-90° C. Higher temperature causes bubble on surface of the cast film. The temperature of the heating oven around the drum may be ranging from 125-140° C. Same machine may be use for casting the film using carrier material. In this method casting solution of deferent batch may be poured from the coating head (FIG. 1 CH1, CH2, CH3, CH4) on the plan surface of carrier material. Coating head has facility to control the flow of batch solution by moving/adjusting the gap between to blade provide in coating head. Carrier material may be polyester film, poly coated film, fabric, metalize paper, metalize polyester film, coated fabric or others. Multilayer film may be produced by online or offline method. Here, R2, R3, R4 and R5 are the finishing roll While CH1, CH2, CH3 and CH4 are coating Head Mountain on drum roll R1.

[0049] Batch Formation: [0050] a) May be made by adding 25% polyvinyl alcohol (GL05 from Ghosenol), and 12% polyvinyl alcohol (173 Kurarey) in deferent vessels with distilled water and heating the mixture with continuous stirring at 60-95° C. to prevent gel formation and to avoid undissolved particle of polyvinyl alcohol, granules/powder is slowly added in cold water and after completing addition, increase the temperature until a clear solution is obtained. Wetting agent anionic surfactant like sodium lauryl sulphate (SLS) or nonionic surfactant alcohol ethoxylate, Triton x-100, Triton x-114 Brig 35 or other may be use in 1-2% W/V. The required amounts of additives, such as glycerol (2-5% W/V), polyethylene glycol (2-10% W/V) of different molecular weight i.e. 400 (3-6% W/V) and 6000 (2-10% W/V), soluble starch (1-8% W/V) are added to the polymeric solution. The clear solution is then filtered and cooled to 30-40° C. Thus two deferent solution is of poly vinyl alcohol is formed. [0051] b) Corn starch solution is prepared by using dissolving 10% starch in water by slowing adding starch in cold water and then increasing the temperature up to 90° C. with continuous stirring for 1 hr. until clear solution. The clear solution is then filtered and cooled to 30-40° C. [0052] C) Blend Preparation [0053] For the preparation of Starch with poly vinyl alcohol, starch of about 10% is added in distilled water. And add gradually starch powder with continues agitation for 30 min, and then increase the temperature of the mixture up to 90° C. for 1 hr. Use solution of poly vinyl alcohol (GL05) and Starch solution in 90:10 ratio in reaction vessel for stirring and heating at 90 deg. cell. For 1 hr. after that filter the solution and cool at room temp. Add other additives like such as glycerol (2-5% W/V), polyethylene glycol of different molecular weight i.e. 400 (3-6% V/V) and 6000 (2-10% W/V), soluble starch (1-8% W/V), propylene glycol (2-6% V/V) are added to the polymeric blend solution. Again stir solution for 30 min and then filtered and cooled to 30-40° C. [0054] d) Solution of polyvinyl acetate is prepared by adding 100 grams of polyvinyl acetate with recommended molecular weight ranging from 40,000 to 100,000 to a reaction vessel containing 1000 ml. of ethyl acetate. The reaction mixture is refluxed until all of the polymer is dissolved. Then, the reaction solution is cooled to room temperature with viscosities ranging from 20-25 sec. (measured with 4-B CUP when measured at 25° C.) [0055] e) blend of polyvinyl acetate and polyvinyl alcohol is formed by mixing solution of (d) and solution of (a) in reaction vessel, reflux the reaction mixture with adding 0-1% surface active agent SLS for 1 hr. and filter then cool at room temperature. The mixing ration PVA:PVAc may be (70:30). [0056] f) solution of all active ingredients 1-20% is dissolve in water and use as per require in solution of (e) and (c).

[0057] The Multi-Layer Film is Cast as Follows:

[0058] A thin coating of GL05 water soluble polymer solution including all ingredients is poured onto a 100 micron polyester film use as carrier material and pass between two rolls. Thickness of the casting film is monitor by adjusting the gap between two rolls. The thickness of this layer is controlled by the viscosity of the casting solution and gape between two rolls. The carrier film passes from heating chamber for 3-4 min. The cast film is dried and the nutritional solution of the middle layer is cast on top of the first dried the film. And, again the thickness of this layer is controlled by the gap between two roller and viscosity of blending solution. The blending ratio of PVAc/PVA is (30:70). Then, after drying, a second layer of a nutritional solution, a third coating is cast on top of the second dried layer. The coated layer is pass from oven to compete drying. Thus, the produce films that are clear, flexible with good mechanical properties. (TABLE: 2)

[0059] Seed Sowing Procedure:

[0060] Seeds of deferent crops can be sowing by using this invented multilayered biodegradable film.

[0061] Encapsulation of seeds are carried out by any convention converting machine, the main important thing in encapsulation is the surface in contact with seed will be bottom layer of multilayer film. FIG. 2). During encapsulation of seed a bio-degradable thread/string may be introduce with seed. This thread is precoated with solution of bottom layer and dried before use. Encapsulation of thread with seeds increase the strength of film. FIG. 3). Another way of encapsulation of seeds with coated biodegradable thread is shown in FIG. 4, where the coated thread in semi dry form is pass from seed containing tray, because of sticky properties of semi dry thread the seeds are stick on the surface of the thread, dry the coated thread by blowing hot air having temperature around 40-50 deg. Cell. Then the coated thread with seeds pass between two laminated web of multilayer biodegradable film passing from two laminating roll (a and b) to prevent the damage of seed by pressing roll, one laminating roll (b) is covered with foam type material while other is having Teflon coated surface. Sealing of two laminated web of laminated biodegradable film may be carried out by applying solution of water and acetone using pen having flat nib of 1-2 cm width (FIG. 4, c). The mixing ratio of water:acetone may be (10:90). The resulting sealed film the pass from hot air having temp. 40-50 deg. Cell. Resulting film may be slit on line or off line as per end use. The encapsulated seeds are sow in soil with depth of about 2-2.5 inch, the moisture of soil may be 30-35%. For comparation study seeds without encapsulation are also sow. Experiment of germination is carried out in room having temperature ranging from 22-28° C. and relative humidity 55-65%. The result of germination and plant growth with and without film for various seeds are shown in Table-1.

TABLE-US-00002 TABLE-1 Plant Germination Height(cm) Plant Height(cm Rate(%) After 7 Days After 14 Days Sr. With Without With Without With Without No. Seeds Film Film Film Film Film Film 1 COWPEA 95 90 15 12.3 18 14 (CHOLI) 2 MOONG 96 90 17 14.3 19.5 16 3 PIGEON PEA 80 60 7 5.3 17 12 (TUVER) 4 VATANA 93 66 4 2 27 18 (PEAS) 5 VAL (INDIAN 95 87 11 9 26 19 BEAN) 6 RAJMA 94 85 7 6 26 22 (FRENCH BEANS) 7 DESI CHANA 90 75 9 8 31 26 8 KABULI 85 70 2.3 1.6 29 17 CHANA 9 WHEAT 92 80 16 12 26 18 10 MAIZE 90 69 12 7 29 19 11 PADDY 98 74 10 8 11 8.3

TABLE-US-00003 TABLE 2 TOP MIDDLE CORE MULTI Properties Units LAYER LAYER LAYER LAYER % Elongation At % 153 45 126 111 Break Tensile Strength kg/cm .Math. sq. 136 210 264 236 Peak Load kg/cm .Math. sq. 0.68 1.05 0.66 2.36 Solubility in sec 10 water at 22° C. COF 0.233 OTR 1.287 Thickness micron 20 20 15 45