Lactose paints

Abstract

Disclosed are paint and coatings compositions comprising a lactose fatty acid ester and methods of making them.

Description

LA CTOSE PAINTSRELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 705,279, filed October 9, 2024.BACKGROUND

[0002] Lactose, a prevalent byproduct of the dairy industry, primarily derived from milk permeate and other cheese byproducts, offers significant potential for novel applications in the paint industry. This document delineates the transformation of lactose into an amphiphilic surfactant suitable for use in paint formulations, circumventing the limitations imposed by traditional milk paints, which rely on casein as a primary binder. By addressing the chemical modification of lactose, this invention not only enhances the value of dairy byproducts but also provides an inherently sustainable and high-performance alternative to existing paint systems.SUMMARY

[0003] In one aspect the present disclosure provides a coating or paint composition, comprising a pigment, a solvent, and a surfactant comprising a lactose fatty acid ester.

[0004] In another aspect, the disclosure provides a method of producing a paint, wherein the method comprises: i) combining anhydrous lactose, a fatty acyl halide, and a solvent, thereby producing a lactose fatty acid ester; ii) isolating the lactose fatty acid ester; and iii) combining a pigment, a second solvent, and the isolated lactose fatty acid esterBRIEF DESCRIPTION OF THE DRAWINGSFigure 1 shows the elements of the present invention including a surfactant derived from esterified lactose without casein, linseed oil as a humectant, and malachite mica, iron ochre, and pre-reduced indigo pigment to form a paint composition with suspended pigment particles.Figure 2A hue saturation value (HSV) spectrum analysis of malachite mica, iron ochre, and pre-reduced indigo paints.Figures 2B and 2C show paint of the present disclosure applied to paper.DETAILED DESCRIPTION

[0005] Lactose constitutes approximately 70 to 80% of the total weight of milk permeate, making it a substantial byproduct of cheese production. While lactose can be marketed as a commodity, its profit margins are relatively modest. The rigorous quality assurance standards imposed on food and pharmaceutical applications further limit its market potential. Conversely, the utilization of lactose in non-food applications, such as paint formulations, presents a lucrative opportunity.

[0006] Historically, milk-based paints, utilizing casein as a binder, have been employed for millennia, with evidence suggesting their use dating back approximately 49,000 years. Casein, a protein derived from milk, is integral to traditional milk paints; however, its depletion during cheese manufacturing poses a challenge for sustainable paint production using milk permeate- derived products.

[0007] The present application seeks to address the inherent limitations of traditional milk paints by chemically transforming lactose into an amphiphilic surfactant. Previous applications of esterified lactose focus upon applications in food emulsification and drug delivery. This invention presents the first application of esterified lactose as a paint binder / surfactant in conjunction with pigment particles. This approach enables the effective utilization of lactose, thereby elevating its status from a low-value commodity to a high-value product in the coatings industry.

[0008] Disclosed is a new type of bio-paint readily derived from lactose (a common byproduct of the dairy industry). This paint is comprised of pigment (e.g., indigo, ochre, and malachite), an oil medium (e.g., linseed oil), and esterified lactose - such as lactose di-saccharides which are given a non-polar ester tail (e.g., palmitoyl and lauryl ester tails). The ester tail creates an amphiphilic molecule with a hydrophobic and a hydrophilic end. Due to this amphiphilic property, esterified lactose has been explored as a food emulsifier and drug delivery medium, but never in conjunction with pigment or as a paint.

[0009] One obvious advantage for esterified lactose as a paint emulsifier / surfactant is that it is non-toxic, biodegradable, and readily abundant from existing waste streams. The dairy industry produces a lot of lactose byproduct as a result of cheese making. It is worth noting that the present invention is fundamentally different from "milk paints" which have been around for millennia and use the protein component of milk "casein" as its fundamental building block. Thepresent invention does not require casein at all; indeed, it does not include any casein which is good because casein is not a common dairy byproduct as it is consumed in cheese manufacturing. Casein paints cure by protein-alkali reactions to form a hard, porous, matte, mineral-like surface that is highly breathable and characteristically “chalky,” with good adhesion to porous substrates but limited flexibility and a propensity to burnish or spot with water before full cure. Casein-based paints therefore have limited utility.

[0010] Finally, when applied to a surface, the present disclosure provides a paint that has not discolored or visually altered at all following over a year of aging. The esterified lactose did not spoil, go off color, or change consistency. This is evidence that the lactose paints of the present disclosure can prove a shelf stable product which is necessary for paints.Definitions

[0011] As used in this application, the term “solvent” is intended to be construed broadly, consistent with its usage in the paints and coatings arts, to encompass not only volatile thinners and diluents, but also the liquid vehicle that carries and binds pigment and other solids. In oilbased systems, such vehicle functions as the binder or medium and may comprise a drying oil, e.g., that undergoes autoxi dati on and crosslinking to form a polymeric or otherwise solid film upon curing. Accordingly, unless the context expressly requires a volatile diluent, “solvent” includes non-volatile, film-forming binders / mediums such as linseed, walnut, safflower, poppy seed, and analogous drying oils, as well as their modified forms (e.g., stand oils, bodied oils), that serve as the base medium and cure to a durable, cross-linked coating. This definition is intended to clarify that the claimed compositions and methods encompass systems in which the “solvent” both carries the pigment during application and remains in the film as the primary binder after drying and polymerization.Embodiments

[0012] The present disclosure provides a coating or paint composition, comprising a pigment, a solvent, and a surfactant comprising a lactose fatty acid ester.

[0013] In some embodiments, the solvent is an oil. In some embodiments, the solvent is selected from linseed (flax), walnut, poppy seed, safflower, sunflower (high-oleic), perilla, hemp, and tung (chinawood) oils. In some embodiments, the solvent is linseed oil.

[0014] In some embodiments, the composition comprises about 0.2 g to about 1.0 g of pigment per 2.0 mL of solvent. In some embodiments, the composition comprises about 0.3 g to about 0.8 g of pigment per 2.0 mL of solvent. In some embodiments, the composition comprises about 0.35 g to about 0.7 g of pigment per 2.0 mL of solvent. In some embodiments, the composition comprises about 0.4 g to about 0.6 g of pigment per 2.0 mL of solvent. In some embodiments, the composition comprises about 0.45 g to about 0.55 g of pigment per 2.0 mL of solvent.

[0015] In some embodiments, the composition comprises about 0.5 g of pigment per 2.0 mL of solvent.

[0016] In some embodiments, the composition comprises a ratio of about 1 part pigment to about 4 parts surfactant. In some embodiments, the composition comprises a pigment-to- surfactant ratio of about 1 : 8 to about 1 : 1. In some embodiments, the composition comprises a pigment-to-surfactant ratio of about 1:6 to about 1:2. In some embodiments, the composition comprises a pigment-to-surfactant ratio of about 1:5 to about 1 :3. In some embodiments, the composition comprises a pigment-to-surfactant ratio of about 1:4.5 to about 1 :3.5. In some embodiments, the composition comprises a pigment-to-surfactant ratio of about 1 :4.25 to about 1:3.75. In some embodiments, the composition comprises a pigment-to-surfactant ratio of about 1:4.1 to about 1 :3.9. In some embodiments, the composition comprises a pigment-to-surfactant ratio of about 1 :4.

[0017] In some embodiments, the lactose fatty acid ester is derived from linear, branched, saturated, or unsaturated C4-C18 fatty acids.

[0018] In some embodiments, the lactose fatty acid ester is derived from saturated fatty acids (C4-C30). In some embodiments, the lactose fatty acid ester is derived from butyric, valeric, caproic, enanthic, caprylic, pelargonic, capric, undecylic, lauric, tridecylic, myristic, pentadecylic, palmitic, margaric, stearic, arachidic, behenic, lignoceric, cerotic, montanic, or melissic acid.

[0019] In some embodiments, the lactose fatty acid ester is derived from monounsaturated fatty acids. In some embodiments, the lactose fatty acid ester is derived from palmitoleic, oleic, elaidic, vaccenic, petroselinic, gondoic, gadoleic, erucic, or nervonic acid.

[0020] In some embodiments, the lactose fatty acid ester is derived from polyunsaturated fatty acids (pufas). In some embodiments, the lactose fatty acid ester is derived from linoleic, alpha-linolenic, gamma-linolenic, stearidonic, arachidonic, eicosapentaenoic, docosapentaenoic, docosahexaenoic, or conjugated linoleic acid.

[0021] In some embodiments, the lactose fatty acid ester is derived from hydroxy and other functionalized fatty acids. In some embodiments, the lactose fatty acid ester is derived from 12- hydroxystearic, ricinoleic, lesquerolic, or vernolic acid.

[0022] In some embodiments, the lactose fatty acid ester is derived from common branched (“iso / anteiso”) and synthetic branched acids. In some embodiments, the lactose fatty acid ester is derived from isostearic, isopalmitic, isononanoic, or isodecanoic acid.

[0023] In some embodiments, the lactose fatty acid ester is derived from short- to medium-chain “met” components. In some embodiments, the lactose fatty acid ester is derived from caprylic, capric, or lauric acid.

[0024] In some embodiments, the lactose fatty acid ester is derived from very long chain specialty fatty acids. In some embodiments, the lactose fatty acid ester is derived from arachidic, behenic, lignoceric, or nervonic acid.

[0025] In some embodiments, the lactose fatty acid ester is derived from octanoic acid, lauric acid, or palmitic acid.

[0026] In some embodiments, the surfactant comprises more than one lactose fatty acid ester.

[0027] In some embodiments, the pigment is selected from natural pigments and botanical dyes.

[0028] Natural pigments are colorants derived from naturally occurring minerals and earths that are processed but not fundamentally altered, valued for their stability, lightfastness, and muted, “earthy” chroma ideal for artist and architectural paints. Non-limiting examples include: yellow ochre (goethite-based iron oxide); red ochre / hematite; raw sienna and burnt sienna (iron oxide with manganese; calcined for “burnt”); raw umber and burnt umber (iron / manganese oxides; calcined for “burnt”); green earth / terre verte (celadonite or glauconite); caput mortuum / Mars violet (purplish iron oxide); natural chalk / whiting (calcium carbonate) as an extender / whitener; bone black and vine / lamp black (carbon blacks); graphite (natural carbon); malachite (basic copper carbonate) and azurite (basic copper carbonate) where available; genuine ultramarine from lapis lazuli in specialty ranges; and historic composites such as Maya Blue.

[0029] Botanical dyes are colorants extracted from plant materials and used directly as dyes or converted to “lake” pigments for paint by precipitating the soluble dye onto an inert substrate, enabling incorporation into binders. Non-limiting examples include: madder root (Rubiatinctorum; alizarin / purpurin reds, often as madder lakes); weld / reseda luteola (luteolin yellows, often as reseda lakes); turmeric / curcumin (strong yellow, commonly laked for paints); annatto / achiote (bixin / norbixin oranges); logwood / haematoxylum (purples to blacks, often laked); brazilwood / sappanwood (reds); sandalwood (reds / oranges); walnut hulls (browns); cutch / catechu (brown to sepia); buckthorn berries and sap green (yellow-greens); safflower (carthamin pinks / reds); henna / lawsone (orange-browns); spirulina / algae pigments (blue / green tones); and indigo from Indigofera or Polygonum tinctorium (reduced as a dye; also used to prepare indigo lakes for paint).

[0030] In some embodiments, the pigment is selected from inorganic mineral pigments and organic vat dyes.

[0031] Inorganic mineral pigments are crystalline, largely insoluble compounds derived from naturally occurring minerals or engineered ceramic solids. Non-limiting examples include: ultramarine blue and violet (synthetic sodium aluminosilicate with sulfur chromophores); Egyptian blue (cuprorivaite, CaCuSi4O10); Prussian blue / iron blue (iron hexacyanoferrate); cobalt aluminate blue (PB28) and cerulean blue / cobalt stannate (PB35); cobalt greens (cobalt zinc oxide spinels, PG19); chromium(III) oxide green (PG17) and hydrated chromium oxide / viridian (PG18); iron oxide earths — reds, yellows, browns, and blacks (hematite, goethite, magnetite); manganese violet (manganese ammonium pyrophosphate); cobalt violet (cobalt phosphate variants); bismuth vanadate yellow (PY184); nickel titanate yellow (PY53) and other mixed-metal oxide titanates; cadmium sulfide / selenide yellows, oranges, and reds (with regulated use); lead chromate and molybdate oranges (legacy chromates, subject to stringent restrictions); and white mineral pigments such as titanium dioxide (rutile / anatase), zinc oxide, and lithopone (zinc sulfide / barium sulfate).

[0032] Organic vat dyes are water-insoluble colorants that are applied via a soluble, reduced “leuco” form and then oxidized back to the insoluble dye, prized for exceptional fastness; several members of this class are also manufactured as pigments for paints when precipitated or milled as insoluble particles. Non-limiting vat dye families and exemplars include: indigo (C.I. Vat Blue 1) from plant or synthetic sources; indanthrone blue / indanthrene (C.I. Vat Blue 4; also sold as Pigment Blue 60 for paints); flavanthrone yellows (e.g., C.I. Vat Yellow 1); pyranthrone oranges (e.g., C.I. Vat Orange 1); thioindigo reds / violets (various C.I. Vat Red designations);and brominated or chlorinated anthraquinone vat greens and violets used for high-fastness applications.

[0033] In some embodiments, the pigment comprises a metal oxide.

[0034] Metal oxide pigments are inorganic colorants composed of oxides or mixed-metal oxides. Non-limiting examples include: iron oxides in red, yellow, and black (Fe2O3, FeOOH, Fe3O4), including blended browns; titanium dioxide (rutile / anatase) for white and opacity control; zinc oxide (white, anti -microbial and drier effects in some systems); chromium(III) oxide green (PG17) and hydrated chromium oxide / viridian (PG18); manganese oxides and manganese-containing earths for umber / browns; mixed-metal oxide spinels such as cobalt aluminate blue (PB28), cobalt chromite greens, and nickel titanate yellow (PY53); and other engineered oxides used for heat- and light-fast architectural and industrial coatings.

[0035] In certain preferred embodiments, the pigment is selected from malachite mica, iron ochre, and pre-reduced indigo.

[0036] The present disclosure provides a method of producing a paint, wherein the method comprises: i. combining anhydrous lactose, a fatty acyl halide, and a solvent, thereby producing a lactose fatty acid ester; ii. isolating the lactose fatty acid ester; and iii. combining a pigment, a second solvent, and the isolated lactose fatty acid ester.

[0037] In some embodiments, the solvent is N-methyl-2-pyrrolidinone.

[0038] In some embodiments, esterifying the anhydrous lactose further comprises a catalyst comprising pyridine.

[0039] In some embodiments, the second solvent is an oil, such as linseed oil.EXAMPLESExample 1: Synthesis of Lactose Paint1. The lactose (72 grams, 0.2 moles) was desiccated at 50°C in the presence of anhydrous sodium sulfate for 8 hours.2. The desiccated lactose was dissolved in 500 mL of N-methyl-2-pyrrolidinone (NMP).3. Pyridine (20 mL) was added to the solution.4. A total of 0.067 moles of a fatty acyl halide of choice was prepared in NMP (tested with octanoyl chloride, lauryl chloride, and palmitoyl chloride).5. The fatty acyl halide solution was added dr op wise into the lactose-pyridine solution while stirring at room temperature, and the mixture was allowed to stir for 5 hours.6. The reaction was quenched with 500 mL of water.7. An equal volume of the reaction mixture and dichloromethane (DCM) was added to a separatory funnel.8. The funnel was shaken gently and then allowed to settle, after which the bottom DCM layer containing the product was decanted. The washing step was repeated 3-4 additional times, each time adding more water to the separatory funnel and agitating before allowing the layers to separate.9. The solids were filtered from the DCM using a vacuum filter.10. For every 2 grams of the fatty ester lactose product, 0.5 grams of pigment and 2.0 mL of solvent (tested with linseed oil) were mixed with a palette knife or other suitable instrument.

[0040] Synthesis was most successful with palmitoyl chloride, yielding considerable solid product. Octanyl and lauryl chloride yielded reduced product and of significantly less dense consistency. Not to be bound by theory, but it is hypothesized that the 16-carbon ester tail conjugated to lactose via palmitoyl chloride results in a more hydrophobic product capable of dissolving in DCM and therefore more easily purified than the 8 carbon and 12 carbon ester tails offered by octanoyl chloride and lauryl chloride. A setup of the paint mixing setup can be seen in Figure 2B. This opens the door for further exploration over a range of ester tail lengths. It could be that certain tail lengths might work best for surfactant applications on different substrates (e.g., concrete, wood, canvas, etc.) or in different application modalities (e.g., spray paint, dried paint powder, oil-based paint, etc.). Alternatively, a mixture of different ester tail lengths (as is naturally present in tallow) might provide a maximally robust chemistry.Example 2: Assessment of Paint Quality

[0041] To assess the paint quality, both a quantitative and a qualitative approach was taken. Individual 3 cm by 3 cm squares of water color paper were prepared and covered by the synthesized paint mixed with 3 naturally occurring, sustainable pigments - Malachite mica, Prereduced indigo, and Yellow ochre.

[0042] Adhering the paint consistently between swatches proved challenging as manual application naturally introduces variation between strokes of paint saturation and stroke length / pressure. To combat the variation, 5 swatches were painted for each pigment and application was intentionally varied between as light a coating as possible and as saturated an application as possible. Joint hue saturation value (HSV) spectrum analysis of all 5 paint swatches for each pigment type were calculated. HSV is a transform on the more common red blue green (RGB) space, capturing all of the same information but with the advantage that the entire visual color spectrum is represented by only one dimension (Hue). This allows analysis of the concentration / consistency of visual color spread via HSV analysis which is not possible in RGB. From the HSV analysis (Figure 2A) it seems the paint prepared with Indigo pigment suffers a diluted spread across multiple hue peaks, Mica exhibits dual hue peaks, and Ochre is concentrated into one peak. This however seems to contradict the qualitative results which show Ochre applications as somewhat “splotchy”, and Indigo and Mica as more even. This discrepancy is possibly explained by the inherent properties of the pigments and their interaction with the binder used in the paint formulation. The “splotchy” appearance can be attributed to the pigment’s texture and granulation, which can cause uneven distribution during application, even if the color itself is concentrated in a specific hue. On the other hand, Indigo and Mica may have more homogenous particle distributions that contribute to smoother application and even spread, despite the HSV analysis indicating a diluted spread for Indigo. The dual hue peaks observed in Mica may suggest that the light reflection and refraction properties of the mica particles create a visual complexity that isn’t captured fully in the HSV analysis. This discrepancy highlights the importance of combining both quantitative and qualitative assessments when evaluating paint quality, as each method provides unique insights into the performance and appearance of the pigments in use.

[0043] For a qualitative analysis, three paintings with the novel paint formulation (Figure 2C) were created. The author found the paints to handle somewhere between acrylic and oil paints - gliding with an easy and malleability of oil paints but generally without the staining and mess of oils. The yellow ochre pigment proved to be a little thin upon application, but the indigo and mica paints held their vibrancy. Additionally, all three paints were readily mixable - affording a full spectrum of mixed pigment hues. Finally, the paintings dried within 2 days at ambient room conditions. After 3 months, the pigment colors have not faded nor shown any signs of wear.INCORPORATION BY REFERENCE

[0044] All US and PCT patent application publications and US patents mentioned herein are hereby incorporated by reference in their entirety as if each individual patent application publication or patent was specifically and individually indicated to be incorporated by reference. In case of conflict, the present application, including any definitions herein, will control.EQUIVALENTS

[0045] While specific embodiments of the subject invention have been discussed, the above specification is illustrative and not restrictive. Many variations of the invention will become apparent to those skilled in the art upon review of this specification and the claims below. The full scope of the invention should be determined by reference to the claims, along with their full scope of equivalents, and the specification, along with such variations.

Claims

CLAIMSWe claim:

1. A coating or paint composition, comprising a pigment, a solvent, and a surfactant comprising a lactose fatty acid ester.

2. The composition of claim 1, wherein the solvent is an oil.

3. The composition of claim 1, wherein the solvent is linseed oil.

4. The composition of any one of claims 1-3, wherein the composition comprises about 0.2 g to about 1.0 g of pigment per 2.0 mL of solvent.

5. The composition of claim 4, wherein the composition comprises about 0.5 g of pigment per 2.0 mL of solvent.

6. The composition of any one of claims 1-5, wherein the composition comprises a ratio of about 1 part pigment to about 4 parts surfactant.

7. The composition of any one of claims 1 -6, wherein the lactose fatty acid ester is derived from linear, branched, saturated or unsaturated C4-C18 fatty acids.

8. The composition of any one of claims 1-7, wherein the lactose fatty acid ester is derived from octanoic acid, lauric acid, or palmitic acid.

9. The composition of any one of claims 1-8, wherein the surfactant comprises more than one lactose fatty acid ester.

10. The composition of any one of claims 1-9, wherein the pigment is selected from natural pigments and botanical dyes.

11. The composition of any one of claims 1-10, wherein the pigment is selected from inorganic mineral pigments and organic vat dyes.

12. The composition of any one of claims 1-11, wherein the pigment comprises a metal oxide.

13. The composition of any one of claims 1-12, wherein the pigment is selected from malachite mica, iron ochre, and pre-reduced indigo.

14. A method of producing a paint, wherein the method comprises: i. combining anhydrous lactose, a fatty acyl halide, and a solvent, thereby producing a lactose fatty acid ester; ii. isolating the lactose fatty acid ester; and iii. combining a pigment, a second solvent, and the lactose fatty acid ester.

15. The method of claim 14, wherein the solvent is N-methyl-2-pyrrolidinone.

16. The method of claim 14 or 15, wherein the step of esterifying the anhydrous lactose further comprises a catalyst comprising pyridine.

17. The method of any one of claims 14-16, wherein the second solvent is an oil (e.g., linseed oil).

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