BACKGROUND

[0001] Solvents play an important role being used in many diverse applications such as paints and coatings, adhesives, inks, personal care and household products. They are also heavily used industrially as, for example, a reaction medium or as an extractant. To select the best solvent a range of technical properties are evaluated including solubility, evaporation rate, and viscosity. However, many technically- suitable solvents are potentially hazardous, and the beneficial aspects of their use must be weighed against negatives that may include, for example, their toxicity, flammability, contribution to global warming, etc.

SUMMARY

[0002] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0003] In one aspect, embodiments disclosed herein relate to solvent systems that include an alkyl tert-butyl ether and at least one selected from the group consisting of ethanol, a hydrocarbon solvent, and an oxygenated solvent.

[0004] In another aspect, embodiments disclosed herein relate to compositions that include at least one resin and a solvent system that includes an alkyl tert-butyl ether and at least one selected from the group consisting of ethanol, a hydrocarbon solvent, and an oxygenated solvent.

[0005] In another aspect, embodiments disclosed herein relate to methods of cleaning a surface of an article, the methods including contacting the surface of the article with a solvent system that includes an alkyl tert-butyl ether and at least one selected from the group consisting of ethanol, a hydrocarbon solvent, and an oxygenated solvent, where the solvent system is added in an amount effective to accomplish cleaning. [0006] In another aspect, embodiments disclosed herein relate to a method of coating a surface of an article, the method included applying a composition onto the surface, where the composition includes at least one resin and a solvent system that includes an alkyl tert-butyl ether and at least one selected from the group consisting of ethanol, a hydrocarbon solvent, and an oxygenated solvent.

[0007] In another aspect, embodiments disclosed herein relate to a method of thinning a first composition, the method including adding a solvent system that includes an alkyl tert-butyl ether and at least one selected from the group consisting of ethanol, a hydrocarbon solvent, and an oxygenated solvent, into the first composition.

[0008] In another aspect, embodiments disclosed herein relate to a method of adhering two articles together, the method comprising applying a composition to at least one of two articles and bringing the two articles in contact with each other, thereby adhering the two articles, where the composition includes at least one resin and a solvent system that includes an alkyl tert-butyl ether and at least one selected from the group consisting of ethanol, a hydrocarbon solvent, and an oxygenated solvent.

[0009] Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.

DETAILED DESCRIPTION

[0010] Alkyl tert-butyl ethers, such as ethyl tert-butyl ether (ETBE), are widely used as an octane booster in gasoline. However, the use of ETBE as a solvent has not been heretofore explored. ETBE is an attractive candidate as a solvent as it may be produced by the reaction of sugarcane-sourced ethanol with isobutylene in a catalytic reaction. The use of renewably-sourced alcohol results in this process providing low carbon emissions (0.34 kg CO2 eq./kg) and yields a final product that may contain 33% biobased carbon.

[0011] In one aspect, embodiments disclosed herein relate to solvent systems that include an alkyl tert-butyl ether and at least one selected from the group consisting of ethanol, a hydrocarbon solvent, and an oxygenated solvent. In particular embodiments, the alkyl tert-butyl ether may be ethyl tert-butyl ether. [0012] In another aspect, embodiments disclosed herein relate to compositions that include a resin and a solvent system comprising an alkyl tert-butyl ether and at least one solvent selected from the group consisting of ethanol, a hydrocarbon solvent, and an oxygenated solvent.

[0013] In another aspect, embodiments disclosed herein relate to methods for using a solvent system, which may include an alkyl tert-butyl ether and at least one selected from the group consisting of ethanol, a hydrocarbon solvent, and an oxygenated solvent. In one or more embodiments, said methods may include thinning a composition, adhering two articles together, or cleaning a surface.

[0014] Two important properties of a solvent are its solvency and evaporation.

Though solvents may be used singly, a single solvent typically does not possess ideal values for both properties, necessitating the use of a solvent mixture or system. Furthermore, the cost of a solvent is also extremely important, not only in terms of production but in storage and handling as well. Therefore, the use of a low-density solvent is often advantageous.

[0015] Embodiments described herein may advantageously provide solvent systems that can dissolve a wide array of solutes, may possess a suitable evaporation rate, and are economically advantageous. Additionally, components of the solvent systems may be at least partially derived from renewable carbon sources, mitigating some of the negative repercussions of solvent use.

[0016] SOLVENT SYSTEMS AND PROPERTIES THEREOF

[0017] Solvent systems in accordance with one or more embodiments of the present disclosure may include one or more alkyl tert-butyl ethers. In one or more embodiments, the alkyl group of the alkyl tert-butyl ether may be a Cl -CIO linear or branched hydrocarbon group. In some embodiments, the alkyl group may be a Cl- C4 linear or branched hydrocarbon group. The alkyl tert-butyl ether of particular embodiments may be ethyl tert-butyl ether.

[0018] In addition to the aforementioned alkyl tert-butyl ethers, solvent systems in accordance with embodiments of the present disclosure may further include one or more additional solvents or co-solvents. In some embodiments, the one or more solvents may be selected from any suitable solvent known to one of skill in the art, but in particular embodiments the one or more solvents may be selected from the group consisting of hydrocarbon solvents and oxygenated solvents, including alcohols.

[0019] The hydrocarbon solvents of one or more embodiments are not particularly limited and may include any suitable solvents, including aromatic and aliphatic species. The aliphatic hydrocarbon solvents of one or more embodiments may be saturated or unsaturated and linear, branched or cyclic. In one or more embodiments, the aliphatic hydrocarbon solvent may be a C6 to CIO hydrocarbon solvent. In particular embodiments, the aliphatic hydrocarbon solvent may be a C6 to C8 hydrocarbon solvent. The aromatic hydrocarbon solvents of one or more embodiments may be monocyclic and may be substituted or unsubstituted. The solvent systems of some embodiments may particularly include alkylbenzenes. In particular embodiments, the solvent system may include one or more of toluene, xylene, and other alkylbenzenes such as mesitylene, ethylbenzene, diethylbenzene, triethylbenzene, cumene, cymene, and the like.

[0020] The oxygenated solvents of one or more embodiments are not particularly limited and may include any suitable oxygen-containing solvent such as ketones, esters, glycols ethers, and alcohols, among others. In particular, solvent systems of some embodiments may include ethanol.

[0021] Solvent systems in accordance with embodiments of the present disclosure may include any suitable amount of alkyl tert-butyl ether. The amount of alkyl tert- butyl ether may range from a lower limit selected from any one of 2 vol%, 3 vol%, 5 vol%, 10 vol%, 15 vol%, and 20 vol% to an upper limit selected from any one of 15 vol%, 20 vol%, 25 vol%, 30 vol%, and 35 vol%, where any lower limit may be paired with any upper limit. In particular embodiments, the alkyl tert-butyl ether is present in the solvent system in an amount ranging from 5 to 30 vol%.

[0022] Solvent systems in accordance with embodiments of the present disclosure may include an alkyl tert-butyl ether in an amount of 5 to 30 vol% and an oxygenated solvent in an amount of 70 to 95 vol%. The amount of oxygenated solvent may range from a lower limit selected from any one of 70 vol%, 73 vol%, 75 vol%, 77 vol%, and 80 vol% to an upper limit selected from any one of 80 vol%, 83 vol%, 85 vol%, 87 vol%, and 90 vol%, where any lower limit may be paired with any upper limit. In particular embodiments, the oxygenated solvent may be ethanol. In other embodiments, the solvent system may contain an alkyl tert-butyl ether in an amount of 5 to 30 vol%, and a mixture of two or more oxygenated solvents in a total amount of 70 to 95 vol%. Each of the oxygenated solvents may be present in an amount of 5 to 90 vol%, relative to the total volume of the solvent system, and each oxygenated solvent may be contained in an amount either the same as or different from one another. In particular embodiments, the amount of each oxygenated solvent may range from a lower limit selected from any one of 5 vol%, 10 vol%, 15 vol%, 20 vol%, 30 vol%, 40 vol%, 50 vol%, 60 vol%, 70 vol%, and 80 vol% to an upper limit selected from any one of 10 vol%, 15 vol%, 20 vol%, 30 vol%, 40 vol%, 50 vol%, 60 vol%, 70 vol%, 80 vol% and 90 vol%, where any lower limit may be paired with any upper limit.

[0023] Solvent systems in accordance with embodiments of the present disclosure may include an alkyl tert-butyl ether in an amount of 5 to 30 vol%, one or more oxygenated solvents in a total amount of 25 to 80 vol%, and one or more hydrocarbon solvents in a total amount of 15 to 70 vol%. In particular embodiments, one of the one or more hydrocarbon solvents is an aromatic solvent, such as an alkylbenzene like xylene, toluene, or mixtures thereof. In some embodiments, the solvent system may comprise two or more hydrocarbon solvents, where at least one is an aliphatic solvent and at least one is an aromatic solvent. In particular embodiments, the amount of an aromatic solvent may range from a lower limit selected from any one of 15 vol%, 20 vol%, 25 vol%, 30 vol%, 40 vol%, 50 vol%, and 60 vol% to an upper limit selected from any one of 20 vol%, 25 vol%, 30 vol%, 40 vol%, 50 vol%, 60 vol%, and 70 vol%, where any lower limit may be paired with any upper limit. In some embodiments, the amount of an aliphatic solvent may range from a lower limit selected from any one of 15 vol%, 20 vol%, 25 vol%, 30 vol%, 40 vol%, 50 vol%, and 60 vol% to an upper limit selected from any one of 20 vol%, 25 vol%, 30 vol%, 40 vol%, 50 vol%, 60 vol%, and 70 vol%, where any lower limit may be paired with any upper limit. In particular embodiments, the total amount of the one or more oxygenated solvents may range from a lower limit selected from any one of 25 vol%, 30 vol%, 40 vol%, 50 vol%, 60 vol%, and 70 vol% to an upper limit selected from any one of 30 vol%, 40 vol%, 50 vol%, 60 vol%, 70 vol%, and 80 vol%, where any lower limit may be paired with any upper limit.

[0024] In one or more embodiments, solvent systems in accordance with the present disclosure may have a bio-based carbon content, as determined by ASTM D6866-18 Method B, of at least 5%, of at least 10%, of at least 20%, or of at least 30%, and up to 33%, 50%, 75%, 90%, or 100%.

[0025] The alkyl tert-butyl ethers of one or more embodiments may be synthesized from an alcohol that contains renewably- sourced carbon. Sources of the renewable carbon may include plant-based sources such as sugar cane and sugar beet, maple, date palm, sugar palm, sorghum, American agave, corn, wheat, barley, sorghum, rice, potato, cassava, sweet potato, algae, fruit, materials comprising cellulose, wine, materials comprising hemicelluloses, materials comprising lignin, wood, straw, sugarcane bagasse, sugarcane leaves, corn stover, wood residues, paper, and combinations thereof.

[0026] The ethyl tert-butyl ether of one or more embodiments may be produced from biologically sourced ethanol obtained by the fermentation of sugars or hydrolyzed starch, derived from the renewable sources of carbon detailed above. It is also envisioned that the biobased ethanol may be obtained from hydrolysis based products from cellulose and hemi- cellulose, which can be found in many agricultural by-products, such as straw and sugar cane husks. This fermentation is carried out in the presence of varied microorganisms, the most important of such being the yeast Saccharomyces cerevisiae.

[0027] The alkyl tert-butyl ether of one or more embodiments of the present disclosure may be synthesized by any suitable method known to one of skill in the art. In particular embodiments, alkyl tert-butyl ether is prepared by the reaction of a suitable alcohol with isobutylene. The isobutylene may be derived from crude oil or natural gas-sourced butane, or from a biobased process utilizing any of the above described plant sources such as from use of sucrose as a feedstock in an Escherichia coli platform (available, for example, from Global Bioenergies) or from conversion of 3-hydroxyisovalerate to isobutene as a side activity of mevalonate diphosphate decarboxylase or on isobutanol dehydration as a side activity of engineered oleate hydratase. [0028] A technical parameter that can be very important for solvent selection is the evaporation rate. Evaporation rate is directly associated to drying time of coatings and adhesives and therefore to productivity. As is indicated in Table 1, alkyl tert- butyl ethers, such as ethyl tert-butyl ether (ETBE), may have a high evaporation rate even relative to traditional solvents like acetone and methyl ethyl ketone.

[0029] Table 1: Evaporation rates of different solvents

[0030] In one or more embodiments, solvent systems in accordance with the present disclosure may have an evaporation rate of 200 or more, 300 or more, 400 or more, 500 or more, 600 or more, or 800 or more, relative to butyl acetate having an evaporation rate of 100. The evaporation rate may be measured by ASTM D 3539 Standard Test Methods for Evaporation Rates of Volatile Liquids by Shell Thin- Film Evaporometer. In particular embodiments, the solvent system may have an evaporation rate of at least 400.

[0031] In one or more embodiments, solvent systems in accordance with the present disclosure may have a maximum incremental reactivity of less than 10 g Cb/g VOC, less than 7 g Cb/g VOC, less than 5 g 0 ₃ /g VOC, less than 3 g 0 ₃ /g VOC, less than 2 g 03/g VOC, or less than 1 g 03/g VOC. In particular embodiments, the solvent system may have a maximum incremental reactivity of less than 3 g 0 ₃ /g VOC. The maximum incremental reactivity may be measured in accordance with a method of William P.L. Carter; Development of Ozone Reactivity Scales for Volatile Organic Compounds, Air & Waste, 1994, 44:7, 881-899.

[0032] The densities of a selection of different solvents are provided in Table 2. In one or more embodiments, solvent systems in accordance with the present disclosure may have a density of less than 0.95 g/cm ³ , less than 0.90 g/cm ³ , less than 0.85 g/cm ³ , less than 0.80 g/cm ³ , or less than 0.75 g/cm ³ . In some embodiments, the solvent system may particularly have a density of less than 0.85 g/cm ³ . The density of the solvent system of one or more embodiments may be measured at 20°C and 1 atm.

[0033] Table 2: Densities of different solvents.

[0034] Two properties particularly relevant for adhesive applications are surface tension and wettability. Wettability is the ability of a liquid to maintain contact with a solid surface, which is dependent upon the nature of the intermolecular forces that arise when the two are brought together and the surface tension of the liquid. As is depicted in Table 3, alkyl tert-butyl ethers, such as ETBE, demonstrate a very low surface tension relative to other solvents.

[0035] Table 3: Surface tension of different solvents

[0036] In one or more embodiments, solvent systems in accordance with the present disclosure may have a surface tension of less than 26 dynes/cm, less than 24 dynes/cm, less than 22 dynes/cm, or less than 20 dynes/cm. [0037] Some alkyl tert-butyl ethers, such as ETBE, are considered to be a non- carcinogenic and non-mutagenic solvent. ETBE also has a low Maximum Incremental Reactivity (MIR), a value that quantifies the propensity of a chemical compound to react in the atmosphere to form ground-level ozone.

[0038] Table 4: MIR values of different solvents.

[0039] In one or more embodiments, solvent systems in accordance with the present disclosure may have an MIR value of less than 6.0, less than 4.0, less than 3.0, less than 2.5, or less than 2.2 g Cb/g product.

[0040] Solvent systems according to the present disclosure will generally possess physical properties suitable for the intended use of the solvent system and/or the compositions produced therefrom. One of ordinary skill in the art will, with the benefit of this present disclosure, appreciate that altering the relative amounts and/or identities of the components of a solvent system will influence the properties of the system.

[0041] COMPOSITIONS

[0042] One or more embodiments of the present disclosure pertain to compositions that include an aforementioned solvent system and at least one solute. In particular embodiments, the solute is fully dissolved in the solvent system.

[0043] The solute of one or more embodiments is not particularly limited. In some embodiments, the solute may be one or more of a resin or polymer. In more particular embodiments, the resins may be selected from acrylic resins, nitrocellulose resins, polyester resins, polyol polyester resins, epoxy resins, alkyd resins, melamine resins, maleic resins, phenolic resins, isocyanate-based resins, polyurethane-based resins, polychloroprene, polyvinyl chloride, chlorinated polyvinyl chloride, styrene butadiene styrene, styrene butadiene, styrene isoprene styrene and ethylene-vinyl acetate (EVA).

[0044] The selection of a solvent or solvent system is initially determined by whether a certain solute will dissolve in said solvent or system. To determine the potential solubility of a material, the Hansen solubility parameters (HSPs) of the solvent and solute may be referenced. Each of the solvent and solute may be described by 3 parameters: 5D - the energy of the dispersion forces between molecules, dr - the energy of the dipole intermolecular forces between molecules, and 5H - the energy of the hydrogen bonds between molecules.

[0045] Using HSPs, the chemical affinity of the solvent can be evaluated for different resins. The closer the solvent’s HSPs are to the resin’s, the more likely it is to dissolve it. HSP theory describes that, to determine if the solvent can effectively dissolve a resin, the relative energy difference (RED) can be calculated: if RED < 1 the system will dissolve, if RED = 1 the system will partially dissolve, and if RED > 1 the system will not dissolve. Table 5 is a comparison between the HSPs of an alkyl tert-butyl ether (specifically, ETBE) and other oxygenated and aromatics solvents. It can be observed that the parameters are similar to both families of solvents.

[0046] Table 5: HSPs for different solvents

[0047] In one or more embodiments, compositions in accordance with the present disclosure may have a relative energy difference between a solvent system and solute of less than 1.1, less than 1.0, less than 0.9, or less than 0.8. [0048] Compositions in accordance with one or more embodiments of the present invention may include one or more additives. The selection of the one or more additives is not particularly limited, and will be highly dependent upon the intended application of the composition. In particular embodiments, the at least one additive may be selected from the group consisting of pigments, dyes, carriers, fillers, and dullness agents. The composition of one or more embodiments may be, for example, a paint composition, a varnish composition, a lacquer composition, an adhesive composition, or a finish composition.

[0049] METHODS

[0050] The aforementioned solvent systems and compositions may be used in a wide array of methods. The uses of solvent systems and compositions in accordance with the present disclosure are not limited to the methods described herein. The solvent systems of one or more embodiments may be used in cleaning compositions, printing inks, varnishes, adhesives, lacquers, or thinners.

[0051] In one or more embodiments, solvent systems in accordance with the present disclosure may be used in a method of cleaning a surface of an article. In some embodiments, the method may include contacting the surface of the article with the solvent system. The amount of solvent system used is not particularly limited but will generally be an amount effective to accomplish cleaning. The cleaning may generate a composition that includes the solvent system and the components that were removed from the surface of the article.

[0052] Further methods that are in accordance with embodiments of the present disclosure may include applying any of the aforementioned compositions to a surface of an article, the composition coating the surface thereof.

[0053] In one or more embodiments, solvent systems in accordance with the present disclosure may be used in a method of thinning a first composition, the method including adding any of the aforementioned solvent systems to the first composition. The identity of the first composition is not particularly limited, but may be a one or more of an alkyl resin, a nitrocellulose resin, or a polyurethane.

[0054] Methods in accordance with one or more embodiments of the present disclosure may involve using the aforementioned compositions to adhere the surfaces of two articles together. In some embodiments, the methods may include applying the composition to the surface of at least one of the two articles and bringing the two articles into contact with each other. In such adhesive applications, it is envisioned that the solvent system may be designed to have a lower evaporation rate, depending on the type of adhesive, for example, and the desired adhesive strength. That is, in some instances, a lower evaporation rate may be desirable to allow the polymer chains to better intermingle (and adhere together) prior to the evaporation of the solvent system. Particular types of adhesive resins that are envisioned as being used with the solvent system of the present disclosure include polyurethane-based resins, polychloroprene, polyvinyl chloride, chlorinated polyvinyl chloride.

[0055] EXAMPLES

[0056] Examples \-\ are solvent systems that are suitable for thinning applications.

As is shown in Table 6, Examples 1-4 contain ETBE and exhibit advantageous properties (such as density, MIR, RED) as compared to Comparative Example 1, which does not contain ETBE.

[0057] Table 6: Thinners for dilution

[0058] Table 7: Thinners for dilution

[0059] Table 8: Thinners for cleaning

[0060] Table 9: Thinners for cleaning [0061] For adhesive applications, alkyl tert-butyl ethers may be used in a wide range of formulations using resins such as polychloroprene, polyurethane, PVC (polyvinyl chloride) and also cPVC (chlorinated polyvinyl chloride). See Tables 10-14. Toluene free compositions for polychloroprene-based adhesives have been developed. Polychloroprene-based resins are widely used in contact adhesives for manufacturing shoes and footwear, in wood industry and furnitures due to their versatility, as they present good results in bonding leather, textiles and other materials

[0062] Table 10: Solvent systems for a polychloroprene based adhesive

[0063] Table 11: Solvent systems for a PU based adhesive

[0064] Table 12: Solvent systems for a PVC based adhesive

[0065] Table 13: Solvent systems for a cPVC based adhesive

[0066] Table 14: Solvent systems for a EVA adhesive

[0067] Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means- plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words‘means for’ together with an associated function.