WO2013022345A1 - Sugar-based plasticizers - Google Patents

Abstract

The invention relates to O-acylated O-alkylated monoglycosides, and to their use as plasticizing or coalescing agents for compositions comprising a thermoplastic polymer. The invention further relates to a method for preparing said O-acylated O-alkylated monoglycosides, and to plastic, coating, ink, adhesive or sealant compositions comprising these O-acylated O-alkylated monoglycosides.

Description

SUGAR-BASED PLASTICIZERS

FIELD OF THE INVENTION

The present invention relates to plasticizers and coalescents, and to methods for producing new compounds for use as plasticizers and coalescents.

BACKGROUND OF THE INVENTION

Plasticizers (or "dispersants") are compounds that are added to polymer-based material compositions, such as plastics, adhesives and paints, to reduce the glass transition temperature (T_g) of these compositions. The use of plasticizers results in an increase of flexibility (elasticity), processability and durability of plastics, which greatly broadens their application possibilities and allows tuning of their properties. In terms of production volumes, plasticizers form the most important plastics additive. About 90% of all plasticizers are applied in polyvinyl chloride (PVC). "Hard" PVC is used in drain pipes and window frames. "Plasticized" PVC may contain up to 60 phr (parts per hundred rubber) of plasticizer, and is applied in, for example, vinyl flooring and rain gear. Phthalate esters form by far the largest class of plasticizers for use in plastics, making up a share of around 84% of the world plasticizer market. Generally, phthalate ester plasticizers owe their popularity to a combination of low price, versatility and excellent technical performance. At present, about 15 different phthalate plasticizers are being produced commercially; of these, «-butylbenzyl phthalate (BBP), di-n-butyl phthalate (DnBP, DBP), di-2-ethylhexyl phthalate (DEHP) and di-isononyl phthalate (DiNP) are the most commonly applied plasticizer compounds.

In coating formulations such as latex paint, plasticizers such as 2,2,4-trimethyl- 1,3-pentanediol monoisobutyrate (Texanol™; Eastman, USA) are incorporated to reduce the glass transition temperature (T_g) of the latex formulation below that of the drying temperature, enabling the formation of a continuous film as the coating cures. In the art, such temporary plasticizers are commonly referred to as "coalescing agents" or simply "coalescents". Plasticizers are not covalently bound to the material to which they are added; as a result, during production, usage and disposal of plasticized materials, plasticizer compounds are emitted to the surroundings due to migration and subsequent leaching and evaporation. As the use of phthalate ester plasticizers is intense and ubiquitous, ranging from baby toys to food packaging to medical disposables to floor covering, there are growing concerns regarding the safety of long- term phthalate exposure. Phthalate esters and their metabolites have been detected in food products such as milk, meat and baby food, and are accumulated in the fat tissue and milk of mammals. Phthalate ester plasticizer accumulation in the body has been associated with negative health effects including endocrine disruption, carcinogenicity, insulin resistance, low birth weight and even attention deficit hyperactivity disorder (ADHD). Accordingly, the European Union has recently imposed a ban on the use of n- butylbenzyl phthalate (BBP), di-n-butyl phthalate (DnBP, DBP) and di-2-ethylhexyl phthalate (DEHP) in children's toys and other children's articles, and on the use of di- isononyl phthalate (Di P) and di-isodecyl phthalate (DiDP) in all articles for children under the age of 3 years.

Likewise, in the field of coatings, coalescing agents are under increasing scrutiny by safety, environmental and health institutions, as the long-term exposure to man-made volatile organic compounds (VOCs) is linked to several adverse respiratory, allergic and immune effects.

The increasing pressure from legislation to reduce the use of harmful and/or volatile coalescing agents and plasticizers as described herein above has motivated the development of alternative compounds capable of reducing the glass transition temperature (T_g) of the composition to which they are added. Commercially available alternative plasticizing/coalescing compounds comprise adipates such as bis(2- ethylhexyl) adipate (DEHA) benzoates such as diethylene glycol dibenzoate (DEGDB), alkyl citrates such as triethyl citrate (TEC) and acetyl tri-n-butyl citrate (ATBC), trimellitates (esters of 1,2,4-benzenetricarboxylic acid), sulfonates, phosphates and polymeric plasticizers such as polycaprolactone-polycarbonate (PCL-PC). A plasticizer comprising fully acetylated 1,2-hydroxy stearic acid glycerol monoester, prepared by esterification of glycerol and castor oil is commercially available as GRINDSTED® SOFT-N-SAFE. EP1058711B 1 discloses isosorbide esters, including isosorbide-2,5-di- 2-ethylhexanoate (IsDEH) for reducing the glass transition temperature of vinyl and styrene acrylic latex coating compositions and PVC plastic.

Alternative solutions to the problem of plasticizer migration and leaching have been sought in the field of surface modification of the polymeric material comprising the plasticizing agent. However, each of these alternative compounds and methods aimed at reducing migration, leakage and bioaccumulation suffer from one or more disadvantages including high volatility, high price, unsatisfactory thermal stability, insufficient versatility, poor hydrolytic stability, modified transparency/opacity, objectionable odor, limited availability and/or reduced effectiveness. For example, while trimellitate plasticizers show less volatility and migration than phthalates, they adversely affect the transparency of PVC foils in which they are incorporated. Citrate plasticizers and coalescents have a favorable toxicological profile; however, this is thwarted by limited thermal stability and increased sensitivity towards microbial decay.

Thus, there is a need in the art for new compounds that form suitable alternatives to the phthalate esters, which compounds are able to reduce the glass transition temperature of the composition to which they are added, but do not suffer from the above-described disadvantages associated with phthalate esters and their present alternatives, and which compounds are environmentally and physiologically safe.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide plasticizers and coalescing agents that do not suffer from the disadvantages summarized herein above. In particular, it is an object of the present invention to provide compounds that are able to reduce the glass transition temperature of the composition to which they are added, that are safer for living organisms and show improved biodegradability. It is a further object to provide materials having plasticizing and coalescing properties that are thermally stable and display limited volatility during processing and use.

The inventors have now found that particular substituted glycosides, more precisely O-acylated monoglycosides, obtainable by O-glycosidation at the anomeric carbon atom of a monosaccharide and acylation (alkanoylation) of its remaining non- anomeric hydroxyl groups, are capable of significantly reducing the glass transition temperature of thermoplastic polymers. A comparison is attached in the Examples section. Hence, the substituted glycosides according to the present invention can be successfully used as a plasticizer in synthetic plastics comprising polyvinyl chloride (PVC), polyvinyl acetate (PVA), rubbers, cellulose plastics, and polyurethane (PU) and polymeric foams, as well as in adhesives, sealants and in coating compositions which cure by coalescence, like inks and acrylic and styrene-acrylic dispersions in water.

The substituted glycosides of the invention are found to be highly compatible with mainstream plastics like PVC even up to levels of 60 phr ("(weight) parts per hundred of rubber"). In addition, they are found to be readily applicable as coalescing agent in customary commercial coating formulations, particularly water-based latex- type compositions. Notably, when mixed in an amount of 20 % (w/w) into PVC they are capable of reducing its glass transition temperature (T_g) with more than 40 °C.

Furthermore, the plasticizing/coalescing compounds according to the invention display thermal stability and volatility comparable to those of state of the art phthalate plasticizers/coalescents.

Accordingly, in one aspect the present invention relates to particular substituted monoglycosides. In another aspect, the invention relates to the use of these substituted monoglycosides as plasticizers and coalescing agents. More specifically, the invention relates to O-acylated O-glycosides, including glycopyranosides and glycofuranosides, wherein the anomeric carbon is O-glycosidated using a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon aglycon moiety "R¹". In these compounds, the remaining available (non-anomeric) hydroxyl groups of the glycosidated monosaccharide are acylated, i.e. the hydrogen atom of the hydroxyl group is replaced with an acyl group R²' wherein R² corresponds to an acyl radical RC=0. Examples include O-acetylation (R = CH₃) and O- propionylation (R = CH₃CH₂). Without wishing to be bound to any theory, it is the belief of the inventors that acylation of the free hydroxyl groups reduces the polarity of the R^-glycosides and improves compatibility with the polymeric matrix to be plasticized. Throughout this text, the O-acylated and O-glycosidated monosaccharide derivatives described above will be referred to as "R¹, R²-substituted (mono)glycosides" or simply "substituted glycosides".

The invention furthermore pertains to a method of reducing the glass transition temperature (T_g) of a composition comprising a thermoplastic polymer, comprising adding an effective amount of the substituted monoglycosides of the invention to said composition.

In another aspect a method of preparing the substituted glycosides according to the invention is provided. Advantageously, the substituted glycosides of the invention may be prepared starting from the cracking products of the biorefinery of agricultural side streams, including wheat, corn (maize) and sugar beet pulp. For instance, sugar beet pulp, the residual tissue after beet sugar production, contains over 70 wt% of polysaccharides, which are predominantly built from glucose, galacturonic acid, arabinose, xylose, and galactose monosaccharide units. Hence, the present invention provides a novel means for utilizing the residual material of food production. As the plasticizing/coalescing compounds of the present invention are derived from naturally occurring sugars, they have great potential as environmentally and physiologically safe additives for application in e.g. food packaging, baby products and children's toys. In one aspect, the invention thus pertains to a polymer-based consumer good comprising an effective amount of the substituted glycosides, i.e. present to an extent that a desirable T_g reducing and/or coalescing effect in the consumer good is attained.

LIST OF PREFERRED EMBODIMENTS

1. A substituted glycoside having the general structure

(I)

wherein x is 2 or 3;

R¹ is a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon having from 1 to 22 carbon atoms;

R² is an acyl group RC=0, wherein R is a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon having from 1 to 22 carbon atoms;

R⁴ is H or CH₂OR²; and

wherein if x = 2 and R⁴ is H, R³ is CH(OR²)R⁵, and R⁵ represents H, COOR¹ or CH₂OR²;

wherein if x = 2 and R⁴ is CH₂OR², R³ is CH₂OR²;

wherein if x = 3 and R⁴ is H, R³ is selected from the group consisting of H, COOR¹, and CH₂OR²;

wherein if x=3 and R⁴ is CH₂OR², R³ is H. 2. Substituted glycoside according to embodiment 1 wherein, if x = 2 and R⁴ is H, R³ is CH₂(OR²), and, if x = 3 and R⁴ is H, R³ is H.

3. Substituted glycoside according to embodiment 1 or 2, wherein R¹ is selected from the group consisting of methyl (CH₃), ethyl (C₂H₅), n-propyl (n-C₃H₇), iso-propyl (i-C₃H₇), n-butyl (η-0₄Η₉), iso-butyl (i-C₄H₉), n-pentyl (n-C₅Hn), iso-pentyl (1-C₅H₁₁), hexyl (C₆Hi₃), 2-ethylhexyl (CH₂CH(C₂H5)C₄H₉), n-octyl (C₈Hi₇), iso-nonyl (C₉H₁₉), i-C₁₀H₂₁ (iso-decyl) and n-dodecyl (n-Ci₂H₂₅), preferably ethyl, n-butyl, i-butyl and i- pentyl.

4. Substituted glycoside according to embodiment 1, 2 or 3, wherein R² is selected from the group consisting of acetyl (CH₃C=0), propionyl (CH₃CH₂C=0), butyryl

(CH₃(CH₂)₂C=0) and pentanoyl (CH₃(CH₂)₃C=0), preferably CH₃C=0 (acetyl) and propionyl (CH₃CH₂C=0).

5. Substituted glycoside according to any one of the preceding embodiments, wherein the substituted glycoside is an arabinofuranoside, xylofuranoside, galacturonic acid furanoside, fructofiiranoside, arabinopyranoside, xylopyranoside, galacturonic acid pyranoside or fructopyranoside, preferably an arabinofuranoside, fructofiiranoside, arabinopyranoside or fructopyranoside.

6. Substituted glycoside according to embodiment 5, wherein the substituted glycoside is an arabinoside.

7. Substituted glycoside according to embodiment 6, wherein the substituted glycoside is chosen from O-propionylated ethyl arabinoside (PrEA), O-propionylated i- pentyl arabinoside (PriPnA), O-acetylated ethyl arabinoside (AEA), O-propionylated n- butyl arabinoside (PrBA), O-acetylated n-butyl arabinoside (ABA), O-propionylated i- butyl arabinoside (PriBA), O-acetylated i-butyl arabinoside (AiBA) or O-acetylated i- propyl arabinoside (AiPA), preferably from O-propionylated ethyl L-arabinoside (PrEA), O-propionylated i-pentyl L-arabinoside (PriPnA), O-acetylated ethyl L- arabinoside (AEA), O-propionylated n-butyl L-arabinoside (PrBA), O-acetylated n- butyl L-arabinoside (ABA), O-propionylated i-butyl L-arabinoside (PriBA), O- acetylated i-butyl L-arabinoside (AiBA) or O-acetylated i-propyl L-arabinoside (AiPA).

8. Substituted glycoside according to any one of the preceding embodiments having a degree of acylation of at least 70%, preferably at least 80%, more preferably at least 85%), most preferably at least 90%. 9. A plastic, coating, ink, adhesive or sealant composition comprising at least a thermoplastic polymer and one or more substituted glycosides according to embodiments 1-8.

10. Composition according to embodiment 9, containing at least 0.5 wt%, based on weight of the thermoplastic polymer, of the one or more substituted glycosides.

11. Composition according to embodiment 9 or 10, having a glass transition temperature lower than 80 °C, preferably lower than 40 °C, more preferably lower than 30 °C, even more preferably lower than 25 °C, yet even more preferably lower than 20 °C, yet even more preferably lower than 15 °C, most preferably lower than 5 °C.

12. Composition according to any one of embodiment 9-11, wherein the composition contains 5-99.5 wt.% of a thermoplastic polymer selected from polyvinyl chloride (PVC), polyurethane (PU), acrylate polymers, acrylate copolymers, ethylene vinyl acetaat (EVA), polystyrene (PS), poly(vinyl butyral) (PVB), poly(vinyl acetate) (PVA), nylon, polyamide, polycelluloid, poly(methyl methacrylate) (PMMA), vinyl acrylic copolymer, styrene/butyl aciylic/methacrylic acid copolymer and combinations thereof, preferably from polyvinyl chloride (PVC), polystyrene (PS), poly (vinyl butyral) (PVB), poly(vinyl acetate) (PVA), nylon, polyamide, polycelluloid, poly(methyl methacrylate) (PMMA), vinyl acrylic copolymer, styrene/butyl aciylic/methacrylic acid copolymer and combinations thereof.

13. Composition according to embodiment 12, wherein the thermoplastic polymer is selected from polyvinyl chloride (PVC) poly(vinyl acetate) (PVA), polyurethane (PU), ethylene vinyl acetaat (EVA), acrylate polymers, acrylate copolymers and combinations thereof.

14. A process of preparing a composition according to any one of embodiments 9- 13, said process comprising combining a thermoplastic polymer with an additive, said additive containing at least 5 wt.% of substituted glycoside according to any one of embodiments 1-8.

14. Use of a substituted glycoside according to any one of embodiment 1-8, or mixtures thereof, as a plasticizer or coalescing agent in a composition comprising a thermoplastic polymer.

15. A method of preparing a substituted glycoside according to any one of embodiments 1-8, comprising the steps, in no particular order, of

O-glycosidation at the anomeric carbon of a monosaccharide or monosaccharide derivative to produce an R^-O-monoglycoside; O-acylation of the non-anomeric hydroxyl groups of said monosaccharide or monosaccharide derivative to produce the corresponding OR² ester, wherein R¹ is a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon having from 1 to 22 carbon atoms; and R² is an acyl group RC=0, wherein R is a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon having from 1 to 22 carbon atoms.

15. Method according to embodiment 14, comprising the consecutive steps of

(i) glycosidation of a monosaccharide in the presence of a catalyst, to produce an R^O-glycoside;

(ii) acylation of the available non-anomeric hydroxyl groups of said R^O- glycoside to produce an O-acylated R^O-glycoside.

DETAILED DESCRIPTION OF THE INVENTION

In one aspect the invention thus pertains to a substituted glycoside having the general structure

(I)

wherein x is 2 or 3;

R¹ is a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon having from 1 to 22 carbon atoms;

R² is an acyl group RC=0, wherein R is a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon having from 1 to 22 carbon atoms;

R⁴ is H or CH₂OR²; and wherein if x = 2 and R⁴ is H, R³ is CH(OR²)R⁵, and R⁵ represents H, COOR¹ or CH₂OR²;

wherein if x=2 and R⁴ is CH₂OR², R³ is CH₂OR²;

wherein if x = 3 and R⁴ is H, R³ is selected from the group consisting of H, COOR¹, and CH₂OR²;

wherein if x=3 and R⁴ is CH₂OR², R³ is H.

Within the context of the present invention, the terms "substituted glycoside", and "(R²) acylation" should be understood to refer to compounds wherein preferably at least 60% of the available non-anomeric hydroxyl groups of the monoglycoside starting material are esterified with an acyl group R², with R² as defined above, i.e. to compounds having a degree of R² acylation, or briefly "acylation degree" of 60% or more. The acylation degree may be determined by saponification of the acylated glycoside and quantification, e.g. using HPLC, of the amount of acid produced on hydrolysis of the glycoside ester. From this, the amount of unsubstituted glycoside is calculated and subsequently the degree of substitution (DS) of the glycoside. The acylation degree corresponds to DS divided by the number of hydroxyl groups in the glycoside that are theoretically available for acylation. Preferably, the acylation degree of the substituted glycosides of the invention is at least 70%, more preferably at least 80%), even more preferably at least 85%>, most preferably at least 90%>.

Within the context of the present invention, the term "plasticizer" refers to a compound that is capable of increasing the plasticity or fluidity of the material composition in which it is incorporated. Although various theories about the mechanism of plasticizing action exist, it is generally accepted that plasticizer molecules are to a smaller or larger extent capable of embedding themselves between the (polymeric) molecules of the composition in need of plasticization, thereby reducing friction between the latter molecules, increasing "free volume" and reducing the glass transition temperature of the composition.

Herein, a "coalescing agent" or "coalescent" is considered a particular sub- species of the concept of plasticizer. More specifically, a "coalescing agent" reduces the glass transition temperature of a coating composition during its curing cycle, thereby facilitating fusion of the coating emulsion droplets ("coalescence") as the solvent evaporates, resulting in satisfactory film formation. As such, a coalescing agent can be considered as a temporary plasticizing agent. In another aspect, the invention pertains to the use of a substituted glycoside as defined above, or mixtures thereof, as a plasticizer or coalescing agent in a composition comprising a thermoplastic polymer.

Preferably, the substituted glycosides of the invention are used as a plasticizing or coalescing agent in plastics (including polymeric foams), coating compositions (including inks), sealants and adhesives.

The R¹ aglycon moiety is bonded through an O-glycosidic linkage at the anomeric position of the sugar moiety. It may optionally be substituted with heteroatoms selected from nitrogen, oxygen, sulfur or phosphor, and/or functional groups chosen from esters, ethers, aldehydes and amides. Preferably, R¹ is selected from the group consisting of CH₃ (methyl), C2H5 (ethyl), n-C₃H₇ (n-propyl), i-C₃H₇ (iso-propyl), n-C₄H9 (n-butyl), i-C₄H₉ (iso-butyl), n-CsHn (n-pentyl), i-CsHn (iso- pentyl; CH₃CH₂CH(CH₃)₂), C₆Hi₃ (hexyl), CH₂CH(C₂H₅)C₄H9 (2-ethylhexyl), C₈Hi₇ (n-octyl), 1-C9H19 (iso-nonyl), i-C₁₀H₂₁ (iso-decyl) and n-Ci₂H₂₅ (n-dodecyl). In a particularly preferred embodiment, R¹ is ethyl, n-propyl, n-butyl, i-butyl or i-pentyl, more preferably ethyl, n-butyl, i-butyl or i-pentyl.

The acyl group R² aids in modulating the polarity of the glycosides. R² may optionally be substituted with heteroatoms selected from nitrogen, oxygen, sulfur or phosphor, and/or functional groups chosen from esters, ethers, aldehydes and amides. In one preferred embodiment, R² is an acetyl (CH₃C=0) or proprionyl (CH₃CH₂C=0) group. It was observed by the inventors that too high viscosities of the substituted glycosides impede mixing with the polymer matrix. It was furthermore found that this viscosity to at least some extent is reduced using longer chain acyl groups at the free hydroxyl positions of the glycosides. Accordingly, in another preferred embodiment R² is propionyl (CH₃CH₂C=0), butyryl (CH₃(CH₂)₂C=0) or pentanoyl (CH₃(CH₂)₃C=0).

Synthesis

The present invention also provides a method for the preparation of the substituted glycosides according to the invention, comprising the steps, in no particular order, of - O-glycosidation at the anomeric carbon of a monosaccharide or monosaccharide derivative to produce an R^O-monoglycoside;

O-acylation of the non-anomeric hydroxyl groups of said monosaccharide or monosaccharide derivative to produce the corresponding OR² ester. Preferably, the substituted glycoside compounds of the invention are prepared according to a process comprising the subsequent steps of

(i) glycosidation at the anomeric carbon of a monosaccharide in the presence of a catalyst, to produce an R^-O-glycoside;

(ii) acylation of the available non-anomeric hydroxyl groups of said R^-O- glycoside to produce an O-acylated R^-O-glycoside.

Herein, R¹ is a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon having from 1 to 22 carbon atoms. R¹ may optionally be substituted with heteroatoms selected from nitrogen, oxygen, sulfur or phosphor, and/or functional groups chosen from esters, ethers, aldehydes and amides; preferably, R¹ is selected from the group consisting of CH₃, C₂H₅, n-C₃H₇, n- C₄H₉, 1-C4H9 (iso-butyl), n-C₅Hn, i-C₅Hn (iso-pentyl), C₆Hi₃, CH₂CH(C₂H5)C4H9 (2- ethylhexyl), C₈Hi₇ (n-octyl), 1-C9H19 (iso-nonyl), i-C₁₀H₂₁ (iso-decyl) and n-Ci₂H₂₅ (n- dodecyl). In a particularly preferred embodiment, R¹ is ethyl, n-propyl, n-butyl, i-butyl or i-pentyl, more preferably ethyl, n-butyl, i-butyl or i-pentyl.

R² is an acyl group (RC=0), wherein R is a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon having from 1 to 22 carbon atoms. R² may optionally substituted with heteroatoms selected from nitrogen, oxygen, sulfur or phosphor, and/or functional groups chosen from esters, ethers, aldehydes and amides.

In one preferred embodiment, R² is an acetyl (CH₃C=0), propionyl (CH₃CH₂C=0), butyryl (CH₃(CH₂)₂C=0) or pentanoyl (CH₃(CH₂)₃C=0) group. In a particularly preferred embodiment, R² is acetyl (CH₃C=0) or propionyl (CH₃CH₂C=0).

Several methods are known in the art for the formation of substituted glycosides, and it is within the ordinary competence of the skilled person to select an appropriate synthesis method. Per J. Garegg, "Synthesis and Reactions Of Glycosides" in Advances in Carbohydrate Chemistry and Biochemistry, Vol. 59, its contents herein incorporated by reference, provides an extensive overview of the state of the art in the synthesis of substituted glycosides.

A particularly suitable method for alkylation of monosaccharides is the Fischer glycosidation (also referred to as "Fischer glycosylation") reaction, involving the formation of a glycoside by the reaction of an unprotected aldose or ketose with a primary alcohol in the presence of an acid catalyst, resulting in the corresponding alkyl O-glycoside.

In case of the use of uronic acid monosaccharides as starting material, such as galacturonic acid, which contain a free carboxylic acid group, said carboxylic acid group is also esterified (producing the corresponding uronic ester group -COOR¹) using this procedure.

Provision of the substituted glycosides of the invention furthermore involves an acylation reaction, replacing the hydrogen atoms of the unsubstituted hydroxyl groups with an acyl group R² to result in alkanoyl ester groups OR², hence providing the O- acylated glycosides according to the invention. Acylation of the glycoside may be performed by reacting with the appropriate acid anhydride or acid halide, such as propionic anhydride, (CH₃CH₂C=0)₂0 or acetyl chloride (CH₃C=OCl), respectively. The acylation reaction is typically performed in the presence of a mild base such as pyridine. As an environmentally benign alternative, ionic liquids may be used as solvent/catalyst in the acylation reaction. Another suitable process for providing the substituted glycosides of the invention involves the Koenigs-Knorr reaction, wherein a glycosyl halide is substituted with an alcohol in the presence of silver promoter to yield the alkyl O-glycoside. In this process, the O-glycosidation reaction is performed on the O-acylated glycosyl halide, i.e., R² substitution is performed prior to R¹ substitution.

Further suitable methods include enzymatic or microbial glycosidations and the

Schmidt alkylation reaction. Alternatively the acylated glycosides can be prepared via a transesterification reaction of an acyl ester (e.g. methyl ester) and the alkyl glycoside with or without the use of a suitable co-solvent.

As defined herein above, acylation is considered to relate to esterification of at least 60% of the available hydroxyl groups at the non-anomeric carbon atoms of the monosaccharide or monosaccharide derivative. Preferably, the acylation degree of the substituted glycosides of the invention is at least 80%, more preferably at least 85%, most preferably at least 90%

The pentose or hexose starting compounds may be keto- or aldo- monosaccharides. As already explained in the summary of the invention, the sugar- based plasticizing/coalescing agents of the invention may advantageously be derived from the cracking products of the biorefinery of agricultural side streams, such as sugar beet pulp or wheat bran. The pentose or hexose monosaccharide starting material is preferably selected from arabinose, xylose, galacturonic acid, galactose, glucose, and fructose, more preferably from arabinose, xylose, galacturonic acid, and fructose. In the aldose and ketose derivatives having the general structure I presented herein above this corresponds to the aldofuranoside (x = 2; R⁴ = H) compounds wherein R³ is CH(OR²)R⁵, and R⁵ represents H (arabinose or xylose derived), COOR¹ (galacturonic acid derived), or CH₂OR² (glucose or galactose derived); to the aldopyranoside (x = 3 ; R⁴ = H) compounds wherein R³ is H (arabinose or xylose derived), COOR¹ (galacturonic acid derived) or CH₂OR² (glucose or galactose derived), respectively; to the ketofuranoside (x=2; R⁴ = CH₂OR²) compounds wherein R³ is CH₂OR² (fructofuranoside); and to the ketopyranose (x=3; R⁴ = CH₂OR²), wherein R³ is H (fructopyranoside). R¹ and R² are as described in detail herein above.

The glycosidation reaction may be catalyzed by homogenous or heterogeneous catalysts. Suitable homogenous catalysts are hydrogen chloride (HC1), sulfuric acid (H₂SO₄) p-toluenesulfonic acid (p-TsOH), boron trifluoride diethyl etherate (BF₃.Et₂0), iodine (I₂) and iron(III) chloride (FeCl₃). Suitable heterogeneous catalysts include macroporous zeolites and acid (ion-exchange) resins like Amberlyst® 15. The substituted glycosides of the invention can be present in the pyranose (six-membered monosaccharide ring, x = 3) or furanose (five-membered ring, x = 2) form. Generally, during synthesis, e.g. in the Fischer glycosidation reaction a mixture of both forms is obtained. The inventors have found that by appropriate choice of catalyst it is possible to influence the ratio of kinetic (furanoside) to thermodynamic (pyranoside) glycoside products of the alkylation reaction. As an example, using Amberlyst® 15 as acid catalyst in the glycosidations of arabinose in ethanol, arabinopyranoside and arabinofuranoside were formed in a molar ratio of 61 :39. This equilibrium can be shifted towards the formation of predominantly, i.e. more than 50 %, preferably more than 60 %, alkyl O-furanosides using catalysts with more Lewis acid character, such as boron trifluoride diethyl etherate (BF₃.Et₂0) and iodine (I₂). In one embodiment, trifluoride diethyl etherate (BF₃.Et₂0) or iodine (I₂) are used as a catalyst in the glycosidation reaction.

Typical compounds according to the invention are acetylated methyl-L- arabinoside, acetylated ethyl-L-arabinoside, acetylated n-propyl-L-arabinoside, acetylated n-butyl-L-arabinoside, acetylated i-butyl-L-arabinoside, acetylated i-propyl- L-arabinoside, acetylated 2-ethylhexyl-L-arabinoside, acetylated octyl-L-arabinoside, propionylated ethyl-L-arabinoside, propionylated n-butyl-L-arabinoside, propionylated i-butyl-L-arabinoside, propionylated i-pentyl-L-arabinoside, iso-butyrylated ethyl-L- arabinoside, iso-butyrylated n-propyl-L-arabinoside, iso-butyrylated i-propyl-L- arabinoside, iso-butyrylated i-pentyl-L-arabinoside, acetylated ethyl glycoside ester of D-galacturonic acid, acetylated n-butyl glycoside ester of D-galacturonic acid, acetylated i-butyl glycoside ester of D-galacturonic acid, acetylated octyl glycoside ester of D-galacturonic acid, acetylated i-pentyl glycoside ester of D-galacturonic acid, acetylated i-propyl glycoside ester of D-galacturonic acid, acetylated n-propyl glycoside ester of D-galacturonic acid, propionylated ethyl glycoside ester of D- galacturonic acid, propionylated i-propyl glycoside ester of D-galacturonic acid, propionylated n-butyl glycoside ester of D-galacturonic acid, propionylated i-butyl glycoside ester of D-galacturonic acid, propionylated i-pentyl glycoside ester of D- galacturonic acid, butyrylated octyl glycoside ester of D-galacturonic acid, butyrylated ethyl glycoside ester of D-galacturonic acid, butyrylated i-propyl glycoside ester of D- galacturonic acid, butyrylated n-butyl glycoside ester of D-galacturonic acid, butyrylated i-butyl glycoside ester of D-galacturonic acid, butyrylated i-pentyl glycoside ester of D-galacturonic acid, acetylated ethyl-D-xyloside, acetylated i-propyl- D-xyloside, acetylated n-propyl-D-xyloside, acetylated i-butyl-D-xyloside, acetylated n-butyl-D-xyloside, acetylated n-pentyl-D-xyloside, propionylated i-propyl-D-xyloside, propionylated n-propyl-D-xyloside, propionylated i-butyl-D-xyloside, propionylated n- butyl-D-xyloside, propionylated i-pentyl-D-xyloside, iso-butyrylated i-propyl-D- xyloside, iso-butyrylated n-propyl-D-xyloside, iso-butyrylated i-butyl-D-xyloside, iso- butyrylated n-butyl-D-xyloside, iso-butyrylated i-pentyl-D-xyloside, acetylated ethyl- D-fructoside, acetylated i-propyl-D-fructoside, acetylated n-propyl-D-fructoside, acetylated i-butyl-D-fructoside, acetylated n-butyl-D-fructoside, acetylated n-pentyl-D- fructoside, propionylated i-propyl-D-fructoside, propionylated n-propyl-D-fructoside, propionylated i-butyl-D-fructoside, propionylated n-butyl-D-fructoside, propionylated i-pentyl-D-fructoside, iso-butyrylated i-propyl-D-fructoside, iso-butyrylated n-propyl- D-fructoside, iso-butyrylated i-butyl-D-fructoside, iso-butyrylated n-butyl-D- fructoside, and iso-butyrylated i-pentyl-D-fructoside, wherein the substituted monoglycosides are present in their 5-membered (furanoside) or 6-membered (pyranoside) ring form, or as a mixture thereof.

Preferred compounds according to the invention are those wherein R¹ = ethyl, n-butyl, i-butyl or i-pentyl; R² = acetyl or propionyl; and for x=2 and R⁴ is H, R³ is CH(OR²)R⁵, with R⁵ representing H (arabinofuranoside, xylofuranoside) or COOR¹ (galacturonic acid furanoside); for x=3 and R⁴ is H, R³ is H (arabinopyranoside, xylopyranoside) or COOR¹ (galacturonic acid pyranoside); for x=2 and R⁴ is CH₂OR², R³ is CH₂OR² (fructofuranoside); for x=3 and R⁴ is CH₂OR², R³ is H (fructopyranoside) .

In another preferred embodiment, the substituted glycoside is an arabinofuranoside, xylofuranoside, galacturonic acid furanoside, fructofuranoside, arabinopyranoside, xylopyranoside, galacturonic acid pyranoside or fructopyranoside, more preferably an arabinofuranoside, arabinopyranoside, fructofuranoside or fructopyranoside.

Particularly preferred compounds are arabinosides, i.e. arabinofuranosides and/or arabinopyranosides. Particularly preferred arabinosides are O-propionylated ethyl arabinoside (PrEA), O-propionylated i-pentyl arabinoside (PriPnA), O-acetylated ethyl arabinoside (AEA), O-propionylated n-butyl arabinoside (PrBA), O-acetylated n- butyl arabinoside (ABA), O-propionylated i-butyl arabinoside (PriBA), O-acetylated i- butyl arabinoside (AiBA) and O-acetylated i-propyl arabinoside (AiPA), in particular O-propionylated ethyl L-arabinoside (PrEA), O-propionylated i-pentyl L-arabinoside (PriPnA), O-acetylated ethyl L-arabinoside (AEA), O-propionylated n-butyl L- arabinoside (PrBA), O-acetylated n-butyl L-arabinoside (ABA), O-propionylated i- butyl L-arabinoside (PriBA), O-acetylated i-butyl L-arabinoside (AiBA) and O- acetylated i-propyl L-arabinoside (AiPA).

Much preferred compounds are O-propionylated ethyl L-arabinoside (PrEA), O- propionylated i-pentyl L-arabinoside (PriPnA), O-acetylated ethyl L-arabinoside (AEA), O-propionylated n-butyl L-arabinoside (PrBA), O-propionylated i-butyl L- arabinoside (PriBA) and O-acetylated n-butyl L-arabinoside (ABA). In a further aspect, the invention pertains to a plastic, coating, ink, adhesive or sealant composition comprising at least a thermoplastic polymer and an effective amount of one or more of the alkyl glycosides of the invention. Preferably, the composition contains at least 0.5 wt%, more preferably at least 1 wt%, even more preferably at least 5 wt%, yet even more preferably at least 10 wt%, most preferably at least 20 wt%, based on weight of the thermoplastic polymer, of the one or more substituted glycosides of the invention. Preferably, the composition has a glass transition temperature lower than 80 °C, preferably lower than 40 °C, more preferably lower than 30 °C, even more preferably lower than 25 °C, yet even more preferably lower than 20 °C, yet even more preferably lower than 15 °C, most preferably lower than 5 °C. Preferably, the composition contains 5-99.5 wt.% of a thermoplastic polymer selected from polyvinyl chloride (PVC); polyurethane (PU), acrylate polymers, acrylate copolymers, ethylene vinyl acetaat (EVA), polystyrene (PS), poly(vinyl butyral) (PVB), poly(vinyl acetate) (PVA), nylon, polyamide, polycelluloid, poly(methyl methacrylate) (PMMA), vinyl acrylic copolymer, styrene/butyl aciylic/methacrylic acid copolymer and combinations thereof

In a more preferred embodiment, the thermoplastic polymer is selected from polyvinyl chloride (PVC), polystyrene (PS), poly(vinyl butyral) (PVB), poly(vinyl acetate) (PVA), nylon, polyamide, polycelluloid, poly(methyl methacrylate) (PMMA), vinyl acrylic copolymer, styrene/butyl aciylic/methacrylic acid copolymer and combinations thereof.

In another particularly preferred embodiment, the thermoplastic polymer is selected from polyvinyl chloride (PVC), poly(vinyl acetate) (PVA), polyurethane (PU), ethylene vinyl acetaat (EVA), acrylate polymers, acrylate copolymers and combinations thereof.

In another aspect, the present invention pertains to a process of preparing a plastic, coating, ink, adhesive or sealant composition as described above, said process comprising combining a thermoplastic polymer with an additive, said additive containing at least 5 wt.% of substituted glycoside according to the invention. In the following, further details are provided on the polymers and additives employed in such compositions.

Plastic compositions

In one embodiment, the invention pertains to a plastic composition comprising one or more thermoplastic polymers and an effective amount of one or more of the acylated glycosides according to the invention. Within the context of the present invention, this plastic composition may refer to the shaped, consumer-ready product or to the liquid/solid base suspensions of polymer and plasticizer in the art also referred to as "plastisol". Additionally, it may refer to polymeric "foams", such as polyurethane foam, polyvinyl chloride (PVC) foam and Styrofoam (polystyrene). Suitable polymers for use in the plastic compositions comprising one or more of the substituted glycosides according to the invention are all vinylic, cellulosic, acrylic and styrene-based polymers and co-polymers, including polyvinyl chloride (PVC), polystyrene (PS), poly(vinyl butyral) (PVB), poly(vinyl acetate) (PVA), nylon, polyamide, polycelluloid and poly(methyl methacrylate) (PMMA). The plastic compositions comprising substituted glycosides according to the invention are prepared using standard processes known to the skilled person, using optional additional components that are common in the art. The plastic composition of the invention comprises from 5 to 100 wt%, preferably 10- 80 wt%, more preferably 20-60 wt%, most preferably 30-50 wt%, based on the weight of the polymer, of one or more of the substituted glycosides according to the invention. Expressed alternatively, the plastic compositions contain 5-100 phr (parts per hundred polymer), preferably 10-80, more preferably 20-60 phr, most preferably 30-50 phr of the glycoside plasticizer of the invention. If no other compounds than the polymer and the plasticizer are present in the composition, this corresponds to 4.76-50 wt%, preferably 9.1-44.4 wt%, more preferably 16.67-37.5, most preferably 23.1-33.3 wt%, based on total weight of the composition, of one or more of the substituted glycosides according to the invention.

Preferably, the glycosides-comprising plastic composition of the invention has a glass transition temperature (T_g) lower than 80 °C, preferably lower than 50 °C, more preferably lower than 40 °C, even more preferably lower than 30 °C, most preferably lower than 20 °C. In one preferred embodiment, a plastic composition comprising (PVC), polystyrene (PS), poly (vinyl butyral) (PVB), poly(vinyl acetate) (PVA), nylon, polyamide, polycelluloid or poly(methyl methacrylate) (PMMA), or mixtures thereof, and from 40 phr of the substituted glycoside plasticizer of the invention has a T_g lower than 25 °C.

Ink or coating composition

In yet another aspect, the invention pertains to a coating composition, preferably a "latex" coating composition, comprising a synthetic resin selected from acrylic latex polymers, vinyl latex polymers, waterborne alkyds and mixtures thereof, a solvent, preferably water, as well as one or more of the substituted glycosides according to the invention.

Latex coating compositions, including latex resin-based inks and latex resin- based paints, cure by a process called coalescence where first the main solvent (usually water), and then the trace, or coalescing, solvent, evaporate and draw together and soften the polymeric binder particles and fuse them together into irreversibly bound networked structures, so that the paint will not redissolve in the solvent/water that originally carried it. In the coating composition of the invention, the substituted glycosides act as a coalescing agent (or "coalescent") by plasticizing the polymer particles, resulting in improved film formation upon water evaporation. It is desirable for the coalescing agent to have low water solubility, which increases its effectiveness, and have good hydrolytic stability.

Polymers suitable for use in the coating composition of the invention are well known in the paint art and are typically applied in the form of particles emulsified or suspended in an aqueous medium. They include, for example, the polymerization products of ethylenically unsaturated monomers, such as alkyl and alkoxy acrylates or methacrylates, vinyl esters of saturated carboxylic acids, mono-olefins, conjugated dienes, optionally with one or more monomers, such as, for example, styrene, methyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, vinyl acetate, acrylonitrile, and vinyl chloride, as well as polyols and polyacids. Preferred coating compositions according to the invention comprise a vinyl acrylic copolymer aqueous latex emulsion or a styrene/butyl aciylic/methacrylic acid copolymer latex emulsion.

These polymers can have a wide range of glass transition temperatures, depending on the desired properties of the resultant coating. The polymers and coalescing agents are present in the coating compositions of the present invention in an amount that provides the desired result. Preferably, the coating composition comprises one or more substituted glycosides according to the invention in an amount of at least 0.1 wt%, more preferably at least 0.5 wt-% and most preferably at least about 2 wt %, based on total weight of the coating composition. Preferably, the one or more substituted glycosides according to the invention are present in the coating composition in an amount of no greater than about 50 wt%, more preferably no greater than about 25 wt% and most preferably no greater than about 10 wt% based on the total weight of the coating composition.

The coating composition of the invention may further comprise other suitable components commonly used in such compositions, including pigments, defoamers, dispersing agents, adhesion promoters, antimicrobial agents etc.

The coating composition according to the invention preferably has a glass transition temperature (T_g) lower than 30 °C, more preferably lower than 25 °C, even more preferably lower than 15 °C, most preferably lower than 5 °C. In one preferred embodiment, a coating composition comprising up to 2.5 wt% of the glycoside plasticizer of the invention has a T_g lower than 15 °C. Adhesives and sealants

In a further aspect, the invention relates to an adhesive or a sealant comprising an effective amount of one or more of the substituted glycosides of the invention. Within the context of the present invention, "adhesives" and "sealants" are understood to comprise all compositions comprising one or more polymeric components that are employed to adhere to or bond items together, or to fill voids in or between materials. These may be drying adhesives and sealants, including solvent based adhesives/sealants and polymer dispersion (emulsion) adhesives/sealants; pressure sensitive adhesives based on e.g. (cyano)acrylates; hot-melt adhesives such as thermoplastic ethylene vinyl acetate; and multi-component glues such as acrylic polymer - polyurethane resin, which cross-link upon combination. In the art, sealants typically have lower strength and higher elongation than adhesives. As for the coating compositions of the invention, the sugar-derived plasticizer compounds of the invention serve to soften the polymer particles and promote their coalescence into a homogeneous continuous film. Preferably, the adhesive or sealant composition comprises one or more substituted glycosides according to the invention in an amount of at least 0.1 wt%, more preferably at least 0.5 wt% and most preferably at least about 2 wt %, based on the total weight of the adhesive or sealant composition. Preferably, the one or more substituted glycosides according to the invention are present in the adhesive or sealant composition in an amount of no greater than about 50 wt%, more preferably no greater than about 25 wt% and most preferably no greater than about 10 wt% based on the total weight of the adhesive or sealant composition. The sealants and adhesives of the present invention may include conventional additives known in the art.

The adhesive or sealant composition according to the invention preferably has a glass transition temperature (T_g) lower than 30 °C, more preferably lower than 25 °C, even more preferably lower than 15 °C, most preferably lower than 5 °C. In one preferred embodiment, an adhesive or sealant composition comprising up to 10 wt% of the glycoside plasticizer of the invention has a T_g lower than 15 °C. Glass transition temperature

The liquid-glass transition temperature, or briefly "glass transition temperature", T_g, is the temperature at which the reversible transition occurs in amorphous materials from a hard and relatively brittle state into a molten or rubber-like state. A number of differing operational definitions of the glass transition temperature T_g are in use. The most frequently used definition of T_g is the temperature or temperature range associated with the energy release (ACp) peak on heating during the glass transition, as measured using differential scanning calorimetry (DSC). A suitable method of determining T_g in polymer-plasticizer mixtures is provided in US2007/0282042, its contents herein incorporated by reference. Briefly, a mixture of ground PVC and plasticizer is heated from 20 to 110 °C at a heating rate of 10 °C/min, held for 3 minutes and cooled rapidly. This is repeated five times to blend the components thoroughly. Then, another run at 10 °C/min is performed to determine T_g. A standardized method is provided in ASTM E 1356

An alternative to DSC analysis is Thermomechanical Analysis (TMA). Another alternative is Dynamic Mechanical Thermal Analysis (DMTA), sometimes called Dynamic Mechanical Rheological Testing (DMRT), wherein T_g is characterized as the temperature at which the material changes from a rigid to a flexible phase. A sinusoidal stress is applied on the material while varying the temperature and the strain in the material is measured, allowing one to determine the elastic modulus E' and loss modulus E" . The glass transition is detected as a sudden and considerable (several decades) change in the elastic modulus and an attendant peak in damping behavior tan5 (Ε"/Ε'). DMTA is more informative about the material before and after the glass transition, as DMTA also measures the rubbery plateau modulus which is much more sensitive to detecting, for example, the effect of adding more plasticizer on elastic modulus. Standardized test methods for thermomechanical analysis (ASTM E 1545) and dynamic mechanical analysis (ASTM E 1640) are available.

Preferably, when incorporated in amounts of between 10 and 60 wt%, preferably 20 and 40 wt% by total weight of the composition, in a polymer-comprising composition, the substituted glycosides of the invention are capable of reducing T_g of said composition with at least 50 °C, more preferably at least 70 °C, even more preferably at least 80 °C, as determined using DSC or DMTA analysis. EXAMPLES

List of abbreviations

IsDEH = isosorbide-2,5-di-2-ethylhexanoate

ATBC = acetyl tri-n-butyl citrate

DEHP = di-2-ethylhexyl phthalate

DiDP = di-iso-decyl phthalate

AMA = acetylated methyl- L-arabinoside

AEA = acetylated ethyl-L-arabinoside

APA = acetylated n-propyl-L-arabinoside

ABA = acetylated n-butyl-L-arabinoside

AiBA = acetylated i-butyl-L-arabinoside

AiPA = acetylated i-propyl-L-arabinoside

AEHA = acetylated 2-ethylhexyl-L-arabinoside

AOA = acetylated octyl-L-arabinoside

PrEA = propionylated ethyl-L-arabinoside

PrB A = propionylated n-butyl-L-arabinoside

PriBA = propionylated i-butyl-L-arabinoside

PriPnA = propionylated i-pentyl-L-arabinoside

iBEA = iso-butyrylated ethyl-L-arabinoside

AEG = acetylated ethyl glycoside ester of D-galacturonic acid

ABG = acetylated butyl glycoside ester of D-galacturonic acid

AOG = acetylated octyl glycoside ester of D-galacturonic acid

AEX = acetylated ethyl-D-xyloside

ABX = acetylated n-butyl-D-xyloside

ABGl = acetylated n-butyl-D-glucoside

ABF = acetylated n-butyl-D-fructoside Example 1 : Synthesis and characterization of O-acylated alkyl-arabinosides

1.1.1 Synthesis of O-ethyl-L-arabinoside (EA)

p-TsOH (0.1 eq, 0.080 mol, 13.8 g) was suspended in ethanol (1200 ml) in an Erlenmeyer flask, and L-(+)-arabinose (120 g, 0.799 mol) was added.

This mixture was stirred overnight at 70 °C. After addition of another 0.025 eq p-TsOH (0.020 mol, 1.68 g), the mixture was stirred at 70 °C for 4 hours. TLC analysis (CH₂Cl₂/MeOH 9: 1) showed complete conversion.

The reaction mixture was cooled to room temperature. 5% NaHC0₃ (0.100 mol; 8.39 g; 167.8 ml) was added to neutralize the reaction mixture to pH 7.1. The reaction mixture was evaporated to yield a light yellow oily residue.

This residue was purified using column chromatography (silica gel 70-230 mesh, 60 A, using CH₂Cl₂/MeOH (100/0→ 90/10) as eluent. The product was obtained as a light yellow oil. Yield: 88.3 % (125.8 g). 1.1.2 Propionylation of O-ethyl-L-arabinoside (PrEA)

The ethyl-L-arabinoside (19.6 g; 0.11 mol) obtained from Example 1.1 was stirred in pyridine (10 eq, 1.10 mol, 89 ml). Propionic anhydride (6 eq, 0.66 mol, 85 ml) was added. The mixture was stirred overnight at room temperature.

The reaction mixture was then poured into 1500 ml of ice water and stirred overnight at room temperature. The aqueous phase was extracted (in portions of ca. 400 ml) with EtOAc (ca. 500 ml). The organic phase was successively washed with H₂0, 2N HC1 (aq), H₂0, 5% NaHC0₃ (aq) and H₂0 (all ca. 500 ml). The organic phase was dried on Na₂SC"4, filtrated and evaporated. The product was obtained as a light yellow liquid, which could be substantially decolored using active coal. Yield: 65.4 % (24.9 g).

1.2.1 Synthesis of n-butyl n-butyl D-galactoside uronate (O-butyl galacturonide; BG); transglycosidation and transesterification with 1-octanol to (O-octyl galacturonide; OG)

p-TsOH (0.1 eq, 0.039 mol, 6.7 g) was suspended in 1-butanol (15 eq, 5.80 mol, 530 ml) in a 2L Erlenmeyer flask, and D-(+)-galacturonic acid.H₂0 (82.0 g, 0.386 mol) was added. This mixture was heated at ± 85 °C during 4 hours and stirred overnight at 60 °C. After addition of another 0.025 eq p-TsOH (0.010 mol, 1.7 g), the mixture was stirred at 85 °C for 4 hours. TLC analysis (CH₂Cl₂/MeOH 9: 1) showed complete conversion. The reaction mixture was partly evaporated (evaporation of ± 250 ml 1-butanol). Subsequently, p-TsOH (0.1 eq, 0.010 mol, 1.7 g) and 1-octanol (10 eq, 3.86 mol, 611 ml) were added. The mixture was heated to 80 °C on a rotary evaporator at 20 mbar, under slow evaporation of 1-butanol. The reaction was proceeded for 6 hours at the rotary evaporator at ± 85 °C and ± 8 mbar. HPLC analysis showed almost complete conversion.

The reaction mixture was cooled to room temperature. 5% NaHC0₃ (aq) (0.125 mol; 4.06 g; 81.2 ml) was added to neutralize the reaction mixture to pH ±7.3. Water was pipetted off. 1-octanol was removed by vacuum distillation, T = 80 - 100 °C, p = ± 1- 2 mmHg, yielding an orange-red oily residue.

This residue was purified in two batches using column chromatography (silica gel 70- 230 mesh, 6θΑ, using CH₂Cl₂/MeOH (100/0→ 85/15) as eluent. The product, octyl octyl D-galactoside uronate was obtained as an orange oil. Yield: 80.7 % (137.4 g). 1.3.1. Synthesis of ethyl xyloside (EX)

p-TsOH (0.1 eq, 0.033 mol, 5.73 g) was suspended in ethanol (10 eq, 3.33 mol, 305 ml) in a 2L Erlenmeyer flask, and D-(+)-xylose acid (50 g, 0.33 mol) was added. This mixture was heated at ± 70 °C during 6 hours and stirred overnight at 60 °C. After addition of another 0.025 eq p-TsOH (0.0083 mol, 1.43 g), the mixture was stirred at 80 °C for 4 hours. TLC analysis (CHCl₂/MeOH 9: 1) showed complete conversion.

The reaction mixture was cooled to room temperature. 5% NaHC0₃ (aq) (0.042 mol; 3.5 g; 69.9 ml) was added to neutralize the reaction mixture to pH ±7.2. The reaction mixture was evaporated to yield a light yellow oily residue.

This residue was purified using column chromatography (silica gel 70-230 mesh, 6θΑ (± 250 g), using CH₂Cl₂/MeOH (100/0→ 90/10) as eluent. The product was obtained as a light yellow oil. Yield 93.4 % (55.4 g).

1.3.2. Acetylation of ethyl xyloside (AEX)

The ethyl-L-xyloside (15.9 g, 0.084 mol) obtained from Example 1.3.2 was stirred in pyridine (10 eq, 0.84 mol, 68 ml). Acetic anhydride (6 eq, 0.51 mol, 47 ml) was added. The mixture was stirred overnight at room temperature.

The reaction mixture was then poured into 1200 ml of ice water and stirred overnight at room temperature. The aqueous phase was extracted (in portions of ca. 400 ml) with EtOAc (ca. 500 ml). The organic phase was successively washed with H₂0, 2N HC1 (aq), H₂0, 5% NaHC0₃ (aq) and H₂0 (all ca. 500 ml). The organic phase was dried on Na₂SC"4, filtrated and evaporated. The product was obtained as a light yellow oil, which could be substantially decolored using active coal. Yield 60.0 % (15.4 g).

1.4.1. Other O-acylated O-alkylated monoglycosides

The other O-acylated O-alkylated monoglycosides described in the Examples below were prepared using closely similar procedures, employing the analogous alkyl alcohols for the (trans)glycosidation and acid anhydrides for the acylation reactions, respectively.

1.4 Degree of acylation

The degree of acylation of a number of acetylated and propionylated glycosides according to the invention was determined by deacylation of a quantity of 1 gram of the compounds using a mixture of 60% iso-propanol and 40% 0.5M NaOH, followed by measurement of the amount (in wt%) of acetic acid or propionic acid liberated from the saponified specimen using HPLC (Column Biorad HPX-87H, 300 x 7,8 mm, Guard column: Biorad HPX-87H, 40 mm; Pump flow 0.5 ml/min, max. pressure 1000 psi (70 bar); injection volume: 20 μΐ loop; detector: RI, T 35°C, eluent: 0.015 M aqueous sulphuric acid, column oven temperature: 65 °C).

The degree of acylation (esterification) is calculated as follows:

1. A = number of moles of acid produced from saponified specimen = wt% acid x 1000 mg/M_w acid; this equals the number of moles of H₂0 consumed;

2. B = number of moles of unsubstituted glycoside after saponification = weight of unsubstituted glycoside/M_w (unsubstituted glycoside)

= (1000 + A x M_w (H₂0) - A x M_w (acid produced)) / M_w (unsubstituted glycoside);

3. Degree of substitution (DS) = A/B;

4. Degree of acylation = DS / DS_max, wherein DS_max denotes the theoretical maximum degree of acylation. Table 1 : Degree of acylation of some compounds of the invention

Table 2: Viscosity

Comparison between the viscosity of some acetylated and propionylated plasticizer compounds of the invention and reference compounds Texanol and acetyl tri-n- butylcitrate (ATBC), determined using an Anton-Paar Physica MCR 301 viscometer equipped with a spindle of 5 cm and 2° angle.

The plasticizers of the invention are more viscous than the reference compounds, but amply fluid for practical application.

Example 2: Thermo Gravimetric Analysis (TGA)

The volatility and temperature stability of a number of compounds of the invention was compared to a reference phthalate plasticizer (di-isodecyl phthalate (DiDP)), by using TGA (Perkin Elmer TGA-7) in the presence and absence of 0₂. TGA measures weight loss of a material as a function of the temperature at a certain heating rate. Weight loss can be caused by evaporation or by degradation (causing formation of volatile compounds). Samples were heated from room temperature to 550 °C at a heating rate of 10 °C/min. The average sample weight was about 20 mg and measurements were performed both under air and nitrogen. Gas flows were at 40 ml/min for the balance and 20 ml/min for the sample gas.

Compared to di-isodecyl phthalate (DiDP), ABG, AOG and ABA were found to display similar TGA profiles, except for showing minor amounts of water. Substantial evaporation of the substituted glycosides commences at temperatures over 200 °C. Hence, the compounds are considered to be thermally stable at processing temperatures (160-200 °C).

Example 3 : Preparation of dry blends

Dry blends were prepared by adding lubricant (3 phr Lankroflex ED06, Akcros), 0.25 phr stearic acid and stabilizer (2 phr liquid Ca/Zn stabilizer LZC-364, Akcros) to PVC (Marvylan S7102, purchased from LVM). The plasticizers of the invention were added last in amounts of 40 and 60 phr (parts per hundred of polymer). After thorough manual mixing of the components, the mixture was heated in an oven overnight at 60 °C. After additional mixing the compound (a dry powder) was ready for processing. Example 4: Compounding on a two roll mill

A two roll mill (Collin Type HOP) was preheated at 166/168 °C (front/rear) and the slit was adjusted to 0.4 mm. The dry blend of Example 3 (80 ± 2 grams) was put on the rolls and left for half a minute. The material was mixed for two and a half minutes by cutting and kneading. After leaving the material on the rotating rolls for another half a minute, the sheet was taken off.

Example 5: Preparation of smooth sheets; compression molding

A compression press (PHI) was preheated at 160°C. A mould (sized 180 x 120 x 1 mm) was filled with about 28 grams roll milled material and covered with PET-foil and steel disks. After heating for 4 minutes at 3 tons, the pressure was raised to 20 tons for 1 minute followed by cooling to room temperature in 10 minutes. DMTA test strips and tensile bars for mechanical testing were cut out of the resulting sheets Example 6: Tensile testing

Testing of mechanical properties was carried out at 20°C on a tensile testing machine (Zwick Z010), equipped with a 1 kN load cell and extensometers. The pressed sheets were punched in test specimen according to ISO-37, type 2 (dumb-bells with overall length 75.0 mm, length of narrow portion 25.0 mm, width of narrow portion 4.0 mm, width of ends 12.5 mm). After clamping the test specimen, the E-modulus was determined with a test speed of 1.0 mm/min. The stress at 100% strain and the strain at break were determined at 500 mm/min. (according to ISO- 1184).

Table 3 displays the results of the tensile testing of PVC sheets as prepared according to Examples 3-5 using 60 phr plasticizer of the invention and DEHP, DIDP, ATBC and GRIND STED® Soft-N-Safe (fully acetylated 1,2-hydroxy stearic acid glycerol monoester, prepared by esterification of glycerol and castor oil) reference plasticizers.

Table 3 : Tensile data of PVC containing 60 phr plasticizer.

These data demonstrate that the tensile data for R¹, R² substituted glycoside plasticizers of the invention are slightly inferior to those of the reference compounds, but amply sufficient for practical application. Example 7: Glass transition temperature (TV) determination in PVC sheets using DMTA

Dynamic Mechanical Thermal Analysis (DMTA) measurements were performed using a DMTA (Rheometrics RSA-2) equipped with a film geometry. A sample (sized appr. 25 x 4 x 1 mm) was fixed and tested in tensile mode with frequency 1.0 Hz at 0.1% strain. A temperature scan was performed from -40°C to 150°C, at a rate of 5°C/min. T_g was chosen to correspond to maximum damping behavior tan5 (Ε"/Ε').

Table 4 displays the glass transition temperature (T_g) of PVC sheets as prepared according to Examples 3-5 using 40 and 60 phr plasticizer of the invention and DEHP, DiDP, ATBC and Soft-N-Safe (Danisco) reference plasticizers.

Table 4: Glass transition temperatures (T_g) of plasticized PVC sheets determined with DMTA.

Example 8: Glass transition temperature (T_£) determination in PVC-plasticizer blends using DSC

5 mg samples of dry mixtures of ground PVC and plasticizer were placed in an aluminum DSC pan and heated from 20 to 1 10 °C at a heating rate of 10 °C/min using a Mettler Toledo DSC821e DSC apparatus. The samples were held for 3 minutes and cooled rapidly. This was repeated five times to blend the components thoroughly. Then, another run at 10 °C/min was performed to determine T_g.

Table 5 displays the glass transition temperature (T_g) of PVC-plasticizer blends, using the plasticizer of the invention and ATBC and Texanol® reference plasticizers. Amounts are 20 wt% plasticizer based on total weight of the blend, unless indicated otherwise.

Table 5: Glass transition temperatures (T_g) of PVC-plasticizer blends determined with Differential Scanning Calorimetry (DSC). Plasticizer Tg (°C)

No plasticizer 90

Texanol 28.1

ATBC 28.3

PrEA 29.2

PrEA 40 wt% 17.0

PrBA 35.1

AEA 34.3

PriPnA 35.0

PriBA 29.3

ABA 37.9

AMA 42.5

APA 40.2

ABA-A 37.4

ABGI 44.4

ABF 36.2

ABX 42.3

These data demonstrate that the R¹, R² substituted glycosides of the invention are capable of reducing T_g of a PVC composition with 40 °C or more when blended in amount of 20 wt% into a PVC composition, with propionylated ethyl-L-arabinoside (PrEA) and propionylated i-butyl-L-arabinoside (PriBA) having comparable T_g reducing capacity as Texanol and ATBC.

Example 9: Preparation of latex compositions

Latex compositions were prepared by adding 2.5 wt%, 5 wt%, and 10 wt% (by weight of the total composition) of substituted glycosides according to the invention to water- continuous emulsions of a commercially available (AkzoNobel) vinyl acrylic copolymer and a styrene/butyl acrylate/methyl methacrylate (S/BA/MAA) copolymer.

Example 10: Glass transition temperature (T_£) determination in latex compositions using DSC

The determination of T_g in latex coating compositions comprising the plasticizers of he invention using Differential Scanning Calorimetry (DSC) was performed by scanning from -15 °C to 50 °C at a rate of 10 °C/min, followed by rapid cooling and recording of a second heating run from -15 °C to 50 °C at 10 °C/min.

The results are presented in Tables 6 A and 6B. Table 6A: Glass transition temperatures (T_g) of vinyl acrylic copolymer latex compositions determined with Differential Scanning Calorimetry (DSC). The T_g of the vinyl acrylic latex compositions without plasticizer was 7.5 °C.

Table 6B: Glass transition temperatures (T_g) of styrene/BA/MMA copolymer latex compositions determined with Differential Scanning Calorimetry (DSC). The T_g of the styrene/BA/MMA copolymer latex compositions without plasticizer was 25.2 °C.

Claims

A substituted glycoside having the general structure

(I)

wherein x is 2 or 3;

R¹ is a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon having from 1 to 22 carbon atoms;

R² is an acyl group RC=0, wherein R is a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon having from 1 to 22 carbon atoms;

R⁴ is H or CH₂OR²; and

wherein if x = 2 and R⁴ is H, R³ is CH(OR²)R⁵, and R⁵ represents H, COOR¹ or CH₂OR²;

wherein if x = 2 and R⁴ is CH₂OR², R³ is CH₂OR²;

wherein if x = 3 and R⁴ is H, R³ is selected from the group consisting of H,

COOR¹, and CH₂OR²;

wherein if x=3 and R⁴ is CH₂OR², R³ is H.

Substituted glycoside according to claim 1 wherein, if x

CH₂(OR²), and, if x = 3 and R⁴ is H, R³ is H.

3. Substituted glycoside according to claim 1 or 2, wherein R¹ is selected from the group consisting of methyl (CH₃), ethyl (C₂H₅), n-propyl (n-C₃H₇), iso-propyl (i-C₃H₇), n-butyl (n-C H₉), iso-butyl (i-C₄H₉), n-pentyl (n-C₅Hn), iso-pentyl (1-C₅H₁₁), hexyl (C₆Hi₃), 2-ethylhexyl (CH₂CH(C₂H₅)C₄H₉), n-octyl (C₈H_n), iso-nonyl (C₉H₁₉), i- C10H21 (iso-decyl) and n-dodecyl (n-Ci2H₂5), preferably ethyl, n-butyl, i-butyl and i- pentyl.

4. Substituted glycoside according to claim 1, 2 or 3, wherein R² is selected from the group consisting of acetyl (CH₃C=0), propionyl (CH₃CH₂C=0), butyryl

(CH₃(CH₂)₂C=0) and pentanoyl (CH₃(CH₂)₃C=0), preferably acetyl CH₃C=0 and propionyl (CH₃CH₂C=0).

5. Substituted glycoside according to any one of the preceding claims, wherein the substituted glycoside is an arabinofuranoside, xylofuranoside, galacturonic acid furanoside, fructofuranoside, arabinopyranoside, xylopyranoside, galacturonic acid pyranoside or fructopyranoside, preferably an arabinofuranoside, fructofuranoside, arabinopyranoside or fructopyranoside. 6. Substituted glycoside according to claim 5, wherein the substituted glycoside is an arabinoside.

7. Substituted glycoside according to claim 6, wherein the substituted glycoside is chosen from wherein the substituted glycoside is chosen from O-propionylated ethyl arabinoside (PrEA), O-propionylated i-pentyl arabinoside (PriPnA), O-acetylated ethyl arabinoside (AEA), O-propionylated n-butyl arabinoside (PrBA), O-acetylated n-butyl arabinoside (ABA), O-propionylated i-butyl arabinoside (PriBA), O-acetylated i-butyl arabinoside (AiBA) or O-acetylated i-propyl arabinoside (AiPA), preferably from O- propionylated ethyl L-arabinoside (PrEA), O-propionylated i-pentyl L-arabinoside (PriPnA), O-acetylated ethyl L-arabinoside (AEA), O-propionylated n-butyl L- arabinoside (PrBA), O-acetylated n-butyl L-arabinoside (ABA), O-propionylated i- butyl L-arabinoside (PriBA), O-acetylated i-butyl L-arabinoside (AiBA) or O- acetylated i-propyl L-arabinoside (AiPA).

8. Substituted glycoside according to any one of the preceding claims having a degree of acylation of at least 70%, preferably at least 80%, more preferably at least 85%), most preferably at least 90%.

9. A plastic, coating, ink, adhesive or sealant composition comprising at least a thermoplastic polymer and one or more substituted glycosides according to claims 1-8.

10. Composition according to claim 9, containing at least 0.5 wt%, based on weight of the thermoplastic polymer, of the one or more substituted glycosides.

11. Composition according to claim 9 or 10, having a glass transition temperature lower than 80 °C, preferably lower than 40 °C, more preferably lower than 30 °C, even more preferably lower than 25 °C, yet even more preferably lower than 20 °C, yet even more preferably lower than 15 °C, most preferably lower than 5 °C.

12. Composition according to any one of claims 9-11, wherein the composition contains 5-99.5 wt.% of a thermoplastic polymer selected from polyvinyl chloride (PVC); polyurethane (PU), acrylate polymers, acrylate copolymers, ethylene vinyl acetaat (EVA), polystyrene (PS), poly(vinyl butyral) (PVB), poly(vinyl acetate) (PVA), nylon, polyamide, polycelluloid, poly(methyl methacrylate) (PMMA), vinyl acrylic copolymer, styrene/butyl aciylic/methacrylic acid copolymer and combinations thereof, preferably from polyvinyl chloride (PVC), polystyrene (PS), poly(vinyl butyral) (PVB), poly(vinyl acetate) (PVA), nylon, polyamide, polycelluloid, poly(methyl methacrylate) (PMMA), vinyl acrylic copolymer, styrene/butyl aciylic/methacrylic acid copolymer and combinations thereof.

13. Composition according to claim 12, wherein the thermoplastic polymer is selected from polyvinyl chloride (PVC), poly(vinyl acetate) (PVA), polyurethane (PU), ethylene vinyl acetaat (EVA) acrylate polymers, acrylate copolymers and combinations thereof.

14. A process of preparing a composition according to any one of claims 9-13, said process comprising combining a thermoplastic polymer with an additive, said additive containing at least 5 wt.% of substituted glycoside according to any one of claims 1-8.

15. Use of a substituted glycoside according to any one of claims 1-8, or mixtures thereof, as a plasticizer or coalescing agent in a composition comprising a thermoplastic polymer.

16. A method of preparing a substituted glycoside according to any one of claims 1- 8, comprising the steps, in no particular order, of

O-glycosidation at the anomeric carbon of a monosaccharide or monosaccharide derivative to produce an R^-O-monoglycoside;

- O-acylation of the non-anomeric hydroxyl groups of said monosaccharide or monosaccharide derivative to produce the corresponding OR² ester, wherein R¹ is a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon having from 1 to 22 carbon atoms; and R² is an acyl group RC=0, wherein R is a linear, cyclic or branched, saturated or unsaturated, substituted or unsubstituted, aliphatic or aromatic hydrocarbon having from 1 to 22 carbon atoms.

17. Method according to claim 16, comprising the consecutive steps of

(i) glycosidation of a monosaccharide in the presence of a catalyst, to produce an R^O-glycoside;

(ii) acylation of the available non-anomeric hydroxyl groups of said R^O- glycoside to produce an O-acylated R^O-glycoside.