BLEACHED SHELLAC AND METHOD FOR PREPARING SAME

This application is being filed on 17 April 2009, as a PCT International Patent application in the name of 1099309 ONTARIO LTD. d/b/a/ ARMALAC INDUSTRIES, a Canadian national corporation, applicant for the designation of all countries except the U.S., and Raymond Patrick Charles Bower, a citizen of Canada, applicant for the designation of the U.S. only, and claims priority to U.S. Provisional Patent Application Serial No. 61/046,611 filed on 21 April 2008.

FIELD OF INVENTION The disclosure relates to bleached shellac and methods for preparing bleached shellac. The disclosure further relates to bleached shellac with low bioburden and robust stability for uses in food, industrial and pharmaceutical applications.

BACKGROUND With increased awareness about the environment, raw materials from petroleum based synthetics and the "green" quotient of consumer products have developed, shellac or shellac modified resins have gained importance due to their unique nontoxic and hypoallergenic properties. Shellac is water soluble, biologically degradable and has film forming, excellent adhesion, hardness, high gloss and superior electrical properties. Shellac or shellac modified resins are also compatible with other resins and can be cross linked, which allows for many other applications.

Shellac was first used as a wood polish for music instruments and furniture and later for uses in spar varnishes with antifouling properties for ship paints, phonographic records, wood and wallpaper paints, printing inks, resins for electrical applications and floor polishes. Today, new applications such as child-safe paints and inks and the coating of fruits and vegetables, food and confections, pills, tablets and vitamins in the pharmaceutical and neutraceutical industries have broadly expanded uses of shellac and require an improved level of safety for the public. Further, recent out-breaks of bovine spongee-form encephalitis (BSE) has caused the pharmaceutical industry to seek alternatives to bovine gelatin for gel capsule coverings.

There is a need for a shellac that has low microbial contamination and robust stability for uses in food, industrial and pharmaceutical applications, as well as methods for producing such a shellac with decreased environmental impact.

SUMMARY

Methods for producing a bleached shellac are described. The method can be a closed process and/or continuous process. The bleached shellac comprises reduced salts, reduced water soluble and water insoluble contaminants, reduced microbial contamination, enhanced shelf life, enhanced hardness, and enhanced scratchability. hi some embodiments, the bleached shellac of the disclosure meets or exceeds current standards for pharmaceutical coatings.

The methods of the invention generally include precipitating a bleached pre- shellac solution with an acid, screening the acid precipitated pre-shellac solution to form a first shellac cake and a mother liquid, and washing the first shellac cake with purified water. The bleached pre-shellac solution can be produced by dissolving seedlac in an alkaline solution comprising a pH of about 7.5 to about 9 at a temperature of about 180 ⁰ F to 212°F to form a seedlac solution, cooling the seedlac solution, bleaching the seedlac solution with low alkaline bleach, screening the bleached seedlac solution to form a separated liquid, bleaching the separated liquid with low alkaline bleach; and filtering the bleached solution to form a filtrated comprises the breached pre-shellac solution. hi some embodiments, a second shellac cake can be formed by heating the mother liquid to a temperature of about 95°F to about 105 ⁰ F, cooling the mother liquid, and screening the cooled mother liquid to form a second shellac cake. The methods of the invention can further include heating the first shellac cake and/or second shellac cakes to a temperature of about 130 ⁰ F to about 150 ⁰ F to form a shellac toffee, cooling the shellac toffee to form shellac, and washing the shellac with purified water, hi some embodiments of the invention, the method uses less than half of the amount of water used in conventional methods.

Methods for de-spoficiation of bleached shellac are also disclosed. The methods generally include germinating spores or inducing germination of spores in a pre-shellac solution, chemically sterlizing the pre-shellac solution, filtering the chemically treated

pre-shellac solution with a 0.5 micron or less filter, and inducing dilute hypochlorous acid in the filtered pre-shellac solution to form a de-sporifϊed pre-shellac solution.

Also described are coatings comprising a bleached shellac of the disclosure and coated substrates comprising said coatings.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a flow diagram illustrating the process steps of an embodiment of the invention for producing bleached shellac.

Figure 2 is a flow diagram illustrating the process steps of an alternative embodiment of the invention for producing bleached shellac.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Conventional methods for making shellac are known. See, for example, Chemistry of Lac, by P. K. Bose, D. Sc. F. N. L, Y. Sankaranarayanan, M. Sc, S. C. Sen Gupta, M. Sc, Indian Lac Research Institute, (1963); Shellac, Angelo Brothers Ltd., Cossipore, Calcutta, India, (1965); Encyclopedia of Polymer Science and Technology, Vol. 12 (N. M. Bikales, ed.) Interscience, New York (1970); and Kirk-Othmer Encyclopedia of Chemical Technology, 3rd Edition, Col. 20 (M. Grayson, ed.) Wiley, N.Y. (1982). Shellac provided by these methods tends to be soft, thermally sensitive, and prone to microbial continuation. In contrast to shellac provided by the conventional methods, the methods of the disclosure provide a bleached shellac having reduced salts, reduced microbial contamination, and enhanced shelf life. In some embodiments, the bleached shellac disclosed herein meets or exceeds current standards for pharmaceutical coatings. The methods of the disclosure also use significantly less water than conventional methods. Conventional methods are known to use about 50 Ib of water per 1 Ib of shellac produced. See, for example, Chemistry of Lac, by P. K. Bose, D. Sc. F. N. L, Y. Sankaranarayanan, M. Sc, S. C. Sen Gupta, M. Sc, Indian Lac Research Institute, (1963). The methods disclosed herein use approximately half the amount of water used in conventional methods. In some embodiments of the invention, the method uses less than half of the amount of water used in conventional methods.

As used herein, "shellac" means a refined or processed shellac resin. Shellac is a natural polyester product comprised of two principle organic acids, shelloic acid and aleuritic acid (9, 10, 16-trihydroxyhexadecanoic acid), in a random polymeric molecule. Natural shellac has been reported to contain about 43% by weight aleuritic acid. Female parasitic insects (Lassifer Lacca Tachacardia Kerr or Coccus Laced) produce a resinous secretion as a protective coating for their larvae. The secretion forms hard layers on branches and twigs of various trees (Ber, Kusum, and Dhak) and bushes in India and Thailand both in the wild and through cultivation. The coated branches are known as sticklac, which is the primary form of the shellac resin. Sticklac typically includes tree bark, branches, twigs, larvae, and other debris. Seedlac is the material recovered from ground and washed sticklac. Seedlac is a raw material for shellac production. Methods

One aspect of the present disclosure is methods of making a bleached shellac that has pharmaceutically acceptable bioburdens, reduced salts, reduced water soluble and water insoluble contaminants, enhanced shelf life, enhanced hardness, and enhanced scratchability. Preferably the bleached shellac of the disclosure meets or exceeds statistical quality assurance standards for effective pathogenic bacterial control. A bleached shellac of the disclosure having a reduced bioburden is generally fit for human consumption and free of human pathogenic bacteria. The methods described herein reduce the bioburden of the bleached shellac in part through de-sporification of the pre-shellac solution. The methods generally comprise germinating spores in a pre-shellac solution; chemically sterilizing the pre-shellac solution; filtering the chemically treated pre-shellac solution with a 0.5 micron or less filter; and inducing dilute hypochlorous acid in the filtered pre-shellac solution to form a de-sporifϊed pre-shellac solution. In an embodiment, the pre-shellac solution is heated to about 180 - 21O ⁰ F, cooled to room temperature or about 7O ⁰ F to about 75 ⁰ F, treated with sodium hypochlorite, filtered to 0.5 microns, and then treated with dilute hypochlorous acid by inducing formation of said acid by adding sulfuric acid to a weak solution of bleach. Referring now to Fig. 1. The process provides seedlac that is dissolved in aqueous media. Debris such as branches, twigs, and bark are typically removed from seedlac

before dissolution in the aqueous media. The dissolution can be carried out for example, using a low shear propeller mixer, that is air driven or a high shear mixer driven at low speed. The aqueous media is adjusted to a pH value of from about 7.5 to 9.0. The pH adjustment step can be performed using any pharmaceutically acceptable base, for example, sodium carbonate or sodium hydroxide. A sufficient amount of purified water is added to the seedlac to result in a solution of from about 5 to about 30% solids based on total weight of the solution at a temperature from about 180 - 21O ⁰ F. As used herein, purified water means water that meets the standards of United States Pharmacopeia (USP) monograph 29. In an embodiment, the purified water is reverse osmosis water or distilled water. Preferably the purified water is low calcium and/or low salt purified water. As described above, the heating also induces germination of spores in the dissolved seedlac.

The resulting solution from the dissolution step (pre-shellac solution) is subjected to a first bleaching stage. Generally the bleaching stage oxidizes materials in the dissolution step to "whiten" or reduce the color of the pre-shellac solution. Care must be taken not to adversely affect the shellac by oxidizing the acids of the natural shellac polymer. Examples of bleaching agents include sodium hypochlorite (NaOCl), hydrogen peroxide (H ₂ O ₂ ), chlorine dioxide and sodium perborate. Typically, the pre-shellac solution is bleached with sodium hypochlorite (low alkaline NaOH; with free chlorine from about 1 - 10% by wt) at a rate of up to 4 g/L, at a rate of from about 0.1 - about 10 gpm.

The ensuing pre-shellac solution is then filtered. The first filtration stage can be performed using, for example, cheese cloth, mesh screens, wire screens, solid bowl centrifugal separation methods, and disc stack centrifugal separations methods. The bleached mixture is filtered through a screen of from about 60 to about 350 mesh, followed by second bleaching stage of the filtrate by adding sodium hypochlorite (low alkaline NaOH; with free chlorine from about 1 - 12.5% by wt) at a rate of up to 4 g/L, at a rate of from about 0.1 - about 10 gpm. In some embodiments, the mixture is filtered to at least 0.5 microns. In some embodiments, sulfuric acid is added to the bleach solution to induce dilute hypochlorous acid. The hypochlorous acid kills virus and spores in the pre-shellac solution.

The ensuing pre-shellac solution from the second bleach stage can be filtered using, for example, a filter press, vacuum filtration, disc stack centrifuge, disposable cartridge filter, or membrane filtration. In an embodiment, the pre-shellac solution is filtered through cotton duct cloth with a filter press comprising diatomaceous earth. In an embodiment, the filter press comprises Celatom FW 12 as precoat on 0.0625 inches on plate and Calatom FW 14 as body coat 25 -50 lbs per batch of 550 pounds. Considerations for selecting a suitable diatomaceous earth includes the level of iron impurities (which inhibits the bleaching and darkens the product), particle size, filtration rate, and darcy permeability, hi an embodiment, the diatomaceous earth is of the calcined fluxed type with a pH greater than 7 and not less than 7. Further considerations in selecting a suitable filter aid include the carrying capacity of the filtering material. Preferably the carrying capacity of the filtering material is sufficient to encapsulate the total natural wax content in the raw lac resin.

After filtration, the pre-shellac solution is subjected to acid precipitation to form shellac. Acid precipitation can be induced by controlled addition of any pharmaceutically acceptable acid, such as sulphuric acid, hydrochloric acid, salt buffers, or organic acids to the pre-shellac solution. One example of a suitable organic acid is acetic acid. The precipitation step can be carried out, for example, by adding sulphuric acid from about 1% to about 5% dilution of concentrated sulphuric acid at a rate of less than about 10 gpm. The ratio of purified water to shellac in the acid precipitation is about 14:1, about 15:1, about 16:1, about 17:1, about 18:1, about 19:1, or about 20:1. hi an embodiment, the ratio of purified water to shellac comprises about 15:1 to about 18:1.

After precipitation, the acid precipitated solution is washed and filtered. The ratio of water to shellac for the wash is about 2:1, about 3:1, about 4: 1 , or about 5:1. hi an embodiment, the ratio of purified water to shellac comprises about 2: 1 to about 3:1. In an embodiment, the ratio comprises about 4 Ib water to 1 Ib shellac. Filtration methods such as vibrational round screener, rectangular vibrational screener, stationary screener, disc stack centrifugal separation, solid bowl centrifugal separation, flat bed screening, or similar methods using elliptical motion, round motion or a combination of vibrational, round, and orbital called universal motion can be used in this separation stage. In an embodiment, the acid precipitated material is put through a centrifugal separator with a

325 mesh screen. The resulting cake is set aside and the filtrate is heated to from about 95 ⁰ F to about 105 ⁰ F, and then cooled. In an embodiment, the cake is cooled to about room temperature. In an embodiment, the cake is cooled to about 7O ⁰ F. Heating can be performed using steam or electrical heating elements within the equipment. The liquid is then screened through a 325 mesh screen and the recovered solid is added to the cake that was earlier set aside. The combined material is then heated to about 13O ⁰ F to about 15O ⁰ F, forming a rubber toffee-like material. The toffee-like material is then cut into hanks in the kettle and moved into a cold water tank to allowing the toffee-like material to become more brittle. The brittle material is then separated from the cold purified water and passed through a chopping mill thus reducing the size of the brittle material. The chopped material is then dried. Suitable drying methods include, but are not limited to, vacuum drying, forced air drying, conical drying, rotary drying, fluidized bed drying, flash drying, belt drying, indirect contact drying, and buell or turbo dryer. In an embodiment, the chopped material is dried under vacuum at reduced atmospheric pressure at a temperature of from about 9O ⁰ F to about 14O ⁰ F. The dried material is then put into a commutation mill, reducing the average size of the material to from about 1 inch to about 0.125 inch, then washing the resulted commutated material with water at a temperature of about from 30.4 - 34.3 ⁰ C, screening, rinsing and cooling the wash in a centrifuge, and drying the material. Suitable drying methods include, but are not limited to, vacuum drying, forced air drying, conical drying, rotary drying, fluidized bed drying, flash drying, belt drying, indirect contact drying, and buell or turbo dryer. In an embodiment, the chopped material is dried under vacuum at reduced atmospheric pressure at a temperature of from about 9O ⁰ F to about 14O ⁰ F. The resulting dried material is then ground to a desired final size. The final grinding can be achieved using a mill, such as a commutation mill, ball mill, or hammer mill. In an embodiment, a commutation mill is used for the final grinding. The resulting ground material can then be packaged. Alternatively, the dried material can be processed to be sold as solutions, for example, as alcoholic solutions for glaze candy coatings, as alkaline solvent solutions for pharmaceutical coatings or as aqueous alkaline solutions for fruit coatings.

Another embodiment of the present disclosure is a continuous system. In an embodiment, the method comprises a dry granulation roll compactor roller press system. Referring now to Fig. 2. The process provides for similar steps to those described in Figure 1. However, after the liquid is screened through a 325 mesh screen and the recovered solid is added to the cake that was earlier set aside, the cake is then processed using a roll compactor roller press system (Chilsonator, available from Separator Engineering Ltd, Scarborough, Ontario, Canada). Materials can be processed into densifϊed sheets in the Chilsonator by the use of mechanical pressure exerted on two compacting rolls. The densifϊed sheets can then be granulated to any desired mesh size. The Chilsonator system has a series of hot rollers that partially melts the product, then the product is cooled to allow for the brittle, chilled product to be delivered to the desired size. The resulting dried material can be packaged or further processed to produce a glaze or coating composition.

As described herein, the methods of the disclosure reduce the bioburden of the bleached shellac. In order to maintain reduced bioburden, the de-sporified pre-shellac solution can be processed into shellac as described herein in a closed system. In some embodiments, the de-sporified pre-shellac solution is processed into shellac as described herein under conditions that meet or exceed US FED STD 209E cleanroom standards, ISO 14644-1 cleanroom standards, and/or BS 5295 cleanroom standards. In some embodiments, the de-sporified pre-shellac solution can be processed into shellac as described herein under aseptic conditions.

The methods of the disclosure also significantly reduce the levels of water soluble and water insoluble contaminates in the bleached shellac. Water insolubles are removed from the pre-shellac solution through screening and filtration in an alkaline solution and from the acidified matrx by screening the shellac cake as described herein and in the examples. Water/alkaline solubles are removed by acidification of the pre-shellac solution and screening of the resultant shellac cake as described herein and in the examples.

The method of the disclosure can also be used to produce shellac wax having reduced microbial contamination. Shellac wax can be a product or by-product of the methods of the disclosure. In an embodiment, the pre-shellac solution from the second

bleach stage is filtered with a centrifugal disc stack centrifuge. The shellac wax is obtained from the top and/or middle fraction.

Shellac compositions The methods of the disclosure provide bleached shellac having reduced salts and reduced microbial contamination. The bleached shellac comprises about 0.3% w/w or less chloride salt, about 0.3% w/w or less sulphate salt, and an alueritic acid concentration that is not less than about 90% of the natural alueritic acid concentration of seedlac. In some examples the bleached shellac of the disclosure comprises about 0.28%, 0.26%, 0.24%, 0.22%, 0.20%, 0.18%, 0.16%, 0.14%, 0.12%, 0.10%, 0.08%, 0.06%, 0.04%, 0.02%, 0.01%, 0.008%, 0.006%, 0.004%, 0.002%, or 0.001% w/w or less chloride salt, hi some examples the bleached shellac of the disclosure comprises about 0.28%, 0.26%, 0.24%, 0.22%, 0.20%, 0.18%, 0.16%, 0.14%, 0.12%, 0.10%, 0.08%, 0.06%, 0.04%, 0.02%, 0.01%, 0.008%, 0.006%, 0.004%, 0.002%, or 0.001% w/w or less sulphate salt, hi some examples, the alueritic acid concentration of the bleached shellac of the disclosure is not less than about 100% , 99%, 98%, 97%, 96%, 95%, 94%, 93%, 92%, 91%, 90%, 89%, 88%, 87%, 86%, 85%, 84%, 83%, 82%, 81%, 80%, 79%, 78%, 77%, 76%, 75%, 74%, 73%, 72%, 71%, rr 70% of the natural alueritic acid concentration of seedlac. hi some examples, the bleached shellac comprises about 20% to about 65% %, about 30% to about 50%, about 40% to about 50%, or about 40% to about 45% w/w alueritic acid.

The bleached shellac of the disclosure comprises reduced microbial contamination, hi an embodiment, the shellac comprises one or more of: (i) an aerobic plate count of 100 colony forming units (CFU) or less per gram (g) of said shellac; (ii) 0 CFU Salmonella typhi per 25 g of said shellac; (iii) 0 CFU Escherichia coli per 10 g of said shellac; (iv) 0 CFU Staphylococcus aureus per 1O g of said shellac; or (v) 0 CFU Pseudomonas aeruginosa per 10 g of said shellac, hi an embodiment, the shellac comprises an aerobic plate count of 100 colony forming units (CFU) or less per gram (g) of said shellac; 0 CFU Salmonella typhi per 25 g of said shellac; 0 CFU Escherichia coli per 1O g of said shellac; 0 CFU Staphylococcus aureus per 1O g of said shellac; and 0 CFU Pseudomonas aeruginosa per 1O g of said shellac.

The bleached shellac of the disclosure comprises a pH of about 3.5 to about 4.5. In an embodiment, the bleached shellac comprises a pH of about 4 to about 3.5. Li an embodiment, the bleached shellac comprises apH of about 3.9 to about 3.5. hi an embodiment, the bleached shellac comprises apH of about 4.5, 4.4, 4.3, 4.2, 4.1, 4.0, 3.9, 3.8, 3.7, 3.6, or 3.5.

The bleached shellac of the disclosure comprises an acid number of about 65 mgKOH/g shellac to about 91 mgKOH/g. hi an embodiment, the bleached shellac comprises an acid number of about 70 mgKOH/g to about 91 mgKOH/g, about 75 mgKOH/g to about 91 mgKOH/g, about 80 mgKOH/g to about 91 mgKOH/g, and about about 85 mgKOH/g to about 91 mgKOH/g. hi an embodiment, the bleached shellac comprises an acid number of about 91, about 90, about 89, about 88, about 87, about 86, about 85, about 84, about 83, about 82, about 81, about 80, about 79, about 78, about 76, or about 75 mgKOH/g.

The bleached shellac of the dislosure can be waxed on unwaxed. In an embodiment, the bleached shellac comprises 5.5% w/w or less of wax. In an embodiment, the bleached shellac comprises 0.2% w/w or less of wax.

The bleached shellac provided by the methods of the disclosure can also include reduced amounts of heavy metals, insoluble matter, rosin, copol, and ash. In prefered embodiments, the bleached shellac comprises about 10 ppm or less of heavy metals, hi an embodiment, the bleached shellac comprises about 9 ppm or less of heavy metals, hi an embodiment, the bleached shellac comprises about 8 ppm or less of heavy metals, hi an embodiment, the bleached shellac comprises about 7 ppm or less of heavy metals, hi an embodiment, the bleached shellac comprises about 6 ppm or less of heavy metals, hi an embodiment, the bleached shellac comprises about 5 ppm or less of heavy metals, hi an embodiment, the bleached shellac comprises about 4 ppm or less of heavy metals. In an embodiment, the bleached shellac comprises about 3 ppm or less of heavy metals, hi an embodiment, the bleached shellac comprises about 2 ppm or less of heavy metals. In an embodiment, the bleached shellac comprises about 1 ppm or less of heavy metals, hi prefered embodiments, the bleached shellac of the disclosure comprises no rosin and/or copol. In prefered embodiments, the bleached shellac comprises 0.2% w/w or less of

insoluble matter. In prefered embodiments, the bleached shellac comprises 0.5 w/w or less of ash.

The bleached shellac of the disclosure comprises a Gardner Helleidge color of about 9 or less. In an embodiment, the bleached shellac comprises a Gardner Helleidge color of about 8 or less. In an embodiment, the bleached shellac comprises a Gardner Helleidge color of about 7 or less. In an embodiment, the bleached shellac comprises a Gardner Helleidge color of about 6 or less. In an embodiment, the bleached shellac comprises a Gardner Helleidge color of about 5 or less.

The bleached shellac of the disclosure comprises a Lovibond color of 2.9r, 29.Oy or less. In an embodiment, the bleached shellac comprises a Lovibond color of 2.15r, 21.5y or less. In an embodiment, the bleached shellac comprises a Lovibond color of 1.7r, 17y or less. In an embodiment, the bleached shellac comprises a Lovibond color of 1.2r, 12.Oy or less. In an embodiment, the bleached shellac comprises a Lovibond color of 0.8r, 8.0y or less. The bleached shellac of the disclosure can be formulated into a shellac solution.

The shellac solution be used as a coating. When dried, the shellac solution provides a hard protective coating useful in the same ways as conventional shellac, such as for example, as a glaze, varnish, or sealer. The shellac solution can be applied using conventional techniques used to apply conventional shellac including, but not limited to, brushing, dripping, spraying, pan coating, or ladling. The solvent in the shellac solution evaporates to leave a hard shellac coating.

A shellac solution can be prepared by mixing the bleached shellac of the disclosure with a solvent, such as a volatile organic solvent or water and a suitable alkalizing agent. Preferrably the water is purified water, such as reverse osmosis water or distilled water. In an embodiment, the purified water has been sterilized. In an embodiment the purified water meets the standards of United States Pharmacopeia (USP) monograph 29. Preferrably the purified water is low calcium and/or low salt purified water. Suitable volatile organic solvents include, but are not limited to, acetone, ethylene glycol butyl ether, methyl propyl carbinol, alcohols, including monohydric, dihydric and polyhydric alcohols, and propylene glycol, ethylene glycol, and diethylene glycol. Preferred alcohols include methanol, ethanol, and isopropyl alcohol.

The shellac sollutions of the disclosure can be used in coatings for coating a substrate, such as a fruit, a vegetable, a food, a pill, a confection, a neutraceutical composition, or a pharmaceutical composition. In a solvent based system, the coating generally comprises about 20% to about 50% shellac solds and about 80% to about 50% solvent. In water based systems, the coating generally comprises about 10% to about 25% shellac solids and a pH of about 7.2-8.5. In solvent/water blends, the coating generally comprises bout 10% to about 40% shellac solides.

The shellac solutions of the disclosure can be used as a coating for a pharmaceutical or neutraceutical. hi an embodiment, shellac produced by the methods of the disclosure is dissolved in alcohol and back titrated with dilute alkaline and water to a pH of about 7.2-8.5 Pharmaceutically acceptable flow additives, surfactants and masking agents can be blended into the sollution. The shellac solutions of the disclosure can also be used as a coating for fruit, hi an embodiment, water is heated to about 140 ⁰ F and an alkaline is added to adjust the pH to about 7.2-8.5. Shellac produced by the methods of the disclosure is added to the water and dissolved. Flow additives, surfactants and masking agents can then be blended into the solution.

Table 1 shows the specifications for an embodiment of a pharmaceutical grade refined bleached (dewaxed) shellac glaze of the invention.

Table 1

Table 2 shows the specifications for an embodiment of a pharmaceutical grade refined bleached (dewaxed) shellac glaze of the invention.

Table 2

Table 3 shows the specification for an embodiment of a pharmaceutical grade refined bleached (waxy) shellac glaze of the invention.

Table 3

Table 4 shows the specification for an embodiment of a pharmaceutical grade refined bleached (waxy) shellac.

Table 4

Uses

The bleached shellac of the disclosure is useful in the same ways as conventional shellac. Shellac of the present disclosure can be used in the preparation of cosmetics and personal care items, for example, but not limited to mascara, nail polish, temporary tattoos, hair sprays, creams and lotions. Other embodiments can include agricultural applications, such as pre-harvest treatment of stone fruit, protecting against splitting or cracking, fruit coating resins, anti-stick agent and post harvest processing.

Further uses of some of the embodiments include confectionary coating applications such as chocolate, gummies, polishing and glazing soft sugar shelled products and polishing and glazing candies and hard sugar shelled products. Other uses include bakery and snack food applications such as spice adhesive, moisture barriers and fat barriers.

Further embodiments of the present disclsoure include pharmaceutical applications such as encapsulation coatings for pills, granulations for pills, moisture barrier coatings for pills, time release coatings for pills, gelatining agent for time release of active pharmaceutical ingreients and time release delivery processes. Other medical

applications for embodiments of the present disclsoure can include liquid bandages and biological adhesives.

Yet other uses for embodiments of the present disclsosure include, but are not limited to, applications in bakery and snack foods. For example, coatings of pralines, cake decorations and sprinkles to prevent colurant and dye bleeding. Other industrial applications of embodiments of the present disclosure include printing inks, wood finishes, lighting lamp base adhesives, hats, ceramics, grinding wheels, candles, adhesives, paints and adhesive glue.

EXAMPLES

The following examples are provided for illustrative purposes only, and are in no way intended to limit the scope of the present application. Many variations and embodiments can be made to the disclosed invention.

Example 1

This example describes one embodiment of the methods of the inventions for producing a pharmaceutical grade refined bleached shellac.

Seedlac was dissolved in a sodium carbonate solution, pH 8.2, at a temperature of 190 F. The pre-shellac solution was cooled to 75 F and sodium hypochlorite (low alkaline NaOH <4 g/L; with 2.75% free chlorine) was added to the pre-shellac solution at a rate of less than 3 gallon per minute (gpm). The pre-shellac solution was then screened through 325 mesh using centrifugal screening and the filtrate rescreened. Sodium hypochlorite (low alkaline NaOH <4 g/L; with 2.75% free chlorine) was then added to the pre-shellac solution at a rate of less than 3 gallon per minute. The bleached pre- shellac solution was filtered through 8 oz cotton duct cloth using a filter press with diatomaceous earth (Celatom FW 12, available from EAGLEP ICHER minerals, as precoat on 0.0625 inches on plate and Celatom FW 14 as body coat 25 -50 lbs per batch of 550 pounds).

After filtration, the pre-shellac was acid precipitated by adding a 2-3% dilution sulphuric acid at a rate of 3 gpm. After precipitation, the acid precipitated pre-shellac solution was processed with a centrifugal separator with 325 mesh screen. The resulting

shellac cake was washed with fresh low calcium, low chloride R.O. water and the mother liquid was added to a kettle and heated to 100 ^° F. The mother liquid was then cooled to 70 ^° F and screened through 325 mesh screen. The shellac cake was added to the first shellac cake and then heated to 140°F to form a rubber toffee. The rubber toffee was cut in the kettle and the hanks were quenched in a cold water hardening tank.

After draining the hardening tank, the hardened shellac was passed through a chopper mill and the hardened shellac was reduced to shellac particles that were about 1 inch in diameter. The shellac particles were dried in a shelf vacuum dryer at a negative pressure of -28 mm Hg and a shelf temperature of 12O ⁰ F and then reduced to about a ¹ A inch in size with a commutation mill. The shellac particles were added to purified water at a ratio of 10:1 and heated to 90 ⁰ F and then pumped into a centrifuge, washed with fresh cold water, and spun dry. The shellac particles were then dried in a shelf vacuum dryer at a negative pressure of -28 mm Hg and a shelf temperature of 120 ⁰ F. After vacuum drying, the shellac was milled with a commutation mill to a size of about 1/8 inch and packaged.

It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. It should also be noted that the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise. All publications and patent applications in this specification are indicative of the level of ordinary skill in the art to which this invention pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated by reference. The invention has been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the invention.