AND THEIR USE IN HOT-MELT ADHESIVES AND BINDERS

FIELD OF THE INVENTION

The invention relates to polyester polyols produced by partially glycolyzing thermoplastic polyesters and use of the polyols in hot-melt adhesive and binder compositions.

BACKGROUND OF THE INVENTION

Thermoplastic polyesters, such as polyethylene terephthalate (PET) from bottles, carpeting, and other sources, provide a practically endless supply of raw material for making valuable intermediate polymers such as polyester polyols. This“upcycling” of waste streams is a sustainable alternative to producing the intermediate polymers from petrochemical-based glycols and aromatic dicarboxylic acids or their derivatives

Frequently, recovered PET is glycolyzed completely to provide monomeric building blocks (e.g., bis(hydroxyethyl) terephthalate, “BHET”) that are reassembled by condensation polymerization. Less often, the PET is only partially glycolyzed, then utilized in that form as an oligomeric intermediate. These oligomeric intermediates are complex mixtures that can be characterized by their ring-and-ball softening points and other properties.

Partially glycolyzed thermoplastic polyesters have potential applicability in hot-melt adhesives. Various kinds of hot-melt adhesives are known. They are usually thermoplastic materials (rather than thermosets) and can be based on ethylene-vinyl acetate (EVA) copolymers, polyolefins, polyamides, polyesters, or polyurethanes. The EVA compositions usually include a paraffinic wax, an EVA copolymer, and a tackifier, often in roughly equal amounts by weight. The tackifier is commonly a rosin ester, a polyterpene, or a terpene-phenol polymer. Partially glycolyzed thermoplastic polyesters have apparently not been used to formulate hot-melt adhesives.

Partially glycolyzed thermoplastic polyesters also have potential value as binders or binder components for asphalt compositions, wood composites, textiles, fireplace logs, and molded composite articles from agricultural or synthetic polymer wastes. The binders present in asphalt compositions oxidize with time and use. In warm climates, breakdown of the binder contributes to rutting, especially near intersections, where slow traffic and braking of heavy vehicles on hot days put incredible stress on road surfaces. It is known to incorporate ground, recycled PET (without glycolysis) into an asphalt composition with binder, aggregate, and other materials, including, for example, recycled rubber from automotive tires. Ideally, the recycled materials could boost the high-temperature performance of an asphalt binder. The potential of partially glycolyzed thermoplastic polyesters for improving binders, however, has apparently not been previously explored.

Humanity benefits from new ways to upcycle thermoplastics and extend the lifecycle for these and other materials previously generated for other purposes from valuable natural resources. And identifying new ways to use waste streams of PET and other thermoplastics in everyday products such as hot-melt adhesives, composites, and asphalt compositions has palpable value.

SUMMARY OF THE INVENTION

In one aspect, the invention relates to a polyester polyol. The polyol comprises a partially glycolyzed reaction product of 65 to 90 wt.% of a thermoplastic polyester and 2 to 15 wt.% of a diol. Optionally, the polyol further comprises 2 to 20 wt.% of a vegetable oil-based hydrophobe; 1 to 5 wt.% of a C4-C36 dicarboxylic acid, diester, or anhydride; or 1 to 25 wt.% of a polyether polyol, or a combination of these. The wt.% values are based on the total amount of charged reactants. The optional polyether polyol comprises recurring units of ethylene oxide, propylene oxide, butylene oxides, or combinations thereof, and has a number-average molecular weight within the range of 500 to 8000 g/mol. The molar ratio of diol to thermoplastic polyester recurring units is less than 0.8, and the polyester polyol has a ring-and-ball softening point as measured by ASTM D-36 within the range of 55°C to 200°C. The polyester polyol is useful for formulating hot-melt adhesives and binder compositions.

In another aspect, the invention relates to a polyester polyol comprising recurring units of 65 to 90 wt.% of a thermoplastic polyester; 2 to 15 wt.% of a diol; 2 to 20 wt.% of a vegetable oil-based hydrophobe; 1 to 5 wt.% of a C4-C36 dicarboxylic acid, diester, or anhydride; and optionally, 1 to 25 wt.% of the polyether polyol described above. The wt.% values are based on the total amount of charged reactants. In this aspect, the polyester polyol has a hydroxyl number as measured by ASTM E-222 within the range of 10 to 50 mg KOH/g, an acid number as measured by ASTM D4662-15 within the range of 10 to 50 mg KOH/g, and a ring-and-ball softening point as measured by ASTM D-36 of at least 40°C. The polyester polyol is useful for formulating hot-melt adhesives and binder compositions.

The invention includes processes for making polyester polyols. One process comprises first reacting 65 to 90 wt.% of a thermoplastic polyester and 2 to 15 wt.% of a diol at a temperature within the range of 125°C to 320°C in the presence of a catalyst to produce a partially glycolyzed intermediate. This intermediate is reacted with 2 to 20 wt.% of a vegetable oil-based hydrophobe; 1 to 5 wt.% of a C4-C36 dicarboxylic acid, diester, or anhydride; and optionally, the polyether polyol described above, at a temperature within the range of 125°C to 320°C to produce a polyester polyol. The wt.% values are based on the total amount of charged reactants. The polyester polyol has a ring-and-ball softening point as measured by ASTM D-36 of at least 40°C. Preferably, the polyester polyol is then cooled, and the resulting solid pellet, sheet, or formed article is then pulverized or pelletized.

In another inventive process, a polyester polyol is made by a process which comprises reacting 65 to 90 wt.% of a thermoplastic polyester; 2 to 15 wt.% of a diol; 2 to 20 wt.% of a vegetable oil-based hydrophobe; 1 to 5 wt.% of a C4-C36 dicarboxylic acid, diester, or anhydride; and optionally, 1 to 25 wt.% of the polyether polyol described above, in a single-screw or twin-screw extruder at one or more temperatures within the range of 125°C to 320°C to produce an extrudate. The wt.% values are based on the total amount of charged reactants. Preferably, the extrudate is then cooled and pulverized or pelletized.

Although glycolysis is most often used to generate monomeric building blocks, we found that partially glycolyzed thermoplastic polyesters can be valuable intermediates for producing hot-melt adhesives and binder compositions. DETAILED DESCRIPTION OF THE INVENTION

The invention relates to polyester polyols produced from partial glycolysis of thermoplastic polyesters with diols, processes for making the polyols, and end-use applications for the polyols, particularly hot-melt adhesives and binder compositions.

A. The polyester polyols

1 . Thermoplastic polyesters

Thermoplastic polyesters suitable for use in making the inventive polyester polyols are well known in the art. They are condensation polymers produced from the reaction of glycols and dicarboxylic acids or acid derivatives, preferably aromatic dicarboxylic acid or acid derivatives. Examples include polyethylene terephthalate (PET); polybutylene terephthalate (PBT); polytrimethylene terephthalate (PTT); glycol-modified polyethylene terephthalate (PETG); copolymers of terephthalic acid and 1 ,4-cyclohexanedimethanol (PCT); PCTA (an isophthalic acid-modified PCT); copolymers of diols with 2,5- furandicarboxylic acid or dialkyl 2,5-furandicarboxylates, e.g., polyethylene furanoate; polylactic acid; copolymers of 2,2,4,4-tetrarmethyl-1 ,3-cyclobutanediol with isophthalic acid, terephthalic acid or orthophthalic derivatives; dihydroferulic acid polymers; copolymers from naphthalene dicarboxylic acids and esters; and the like, and mixtures thereof. Further examples of polyester thermoplastics are described in Modern Polyesters: Chemistry and Technology of Polyesters and Copolvesters. J. Scheirs and T. Long, eds., Wiley Series in Polymer Science, 2003, John Wiley & Sons, Ltd. Hoboken, NJ. Other examples of thermoplastic polyesters may be found in Chapters 18-20 of Handbook of Thermoplastics. O. Olabisi, ed., 1997, Marcel Dekker, Inc. New York. Suitable thermoplastic polyesters include virgin polyesters, recycled polyesters, or mixtures thereof. Polyethylene terephthalate is particularly preferred, especially recycled polyethylene terephthalate (rPET), virgin PET, recycled PETG, virgin PETG, and mixtures thereof. Sources of glycol-modified PETG include virgin PETG, recycled PETG containers, PETG dunnage, PETG packaging, and the like. For more examples of suitable thermoplastic polyesters, see U.S. Pat. Appl. Publ. No. 2009/0131625, the teachings of which are incorporated herein by reference. Recycled polyethylene terephthalate suitable for use in making the inventive polyester polyols can come from a variety of sources. The most common source is the post-consumer waste stream of PET from plastic bottles or other containers. The rPET can be colorless or contain dyes (e.g., green, blue, or other colors) or be mixtures of these. A minor proportion of organic or inorganic foreign matter (e.g., paper, other plastics, glass, metal, etc.) can be present. A desirable source of rPET is“flake” rPET, from which many of the common impurities present in scrap PET bottles have been removed in advance. Another desirable source of rPET is pelletized rPET, which is made by melting and extruding rPET through metal filtration mesh to further remove particulate impurities. Because PET plastic bottles are currently manufactured in much greater quantity than any recycling efforts can match, scrap PET will continue to be available in abundance.

Other sources of PET include PET textiles and PET carpeting, such as recycled PET textiles and recycled PET carpeting. For example, recycled PET polyester carpet including polyolefin backing, calcium carbonate filler, and latex adhesive is a useful source of thermoplastic polyester. In certain aspects of the practice of this invention, the PET content of the recycled PET originating from PET content carpet may be greater than 90%, greater than 80%, greater than 70%, or even greater than 50% by weight of the recycled carpet.

Other sources of PTT include PTT textiles and PTT carpeting, such as recycled

PTT textiles and recycled PTT carpeting. For example, recycled PTT polyester carpet including polyolefin backing, calcium carbonate filler, and latex adhesive is a useful source of thermoplastic polyester. In certain aspects of the practice of this invention, the PTT content of the recycled PTT originating from PTT content carpet may be greater than 90%, greater than 80%, greater than 70%, or even greater than 50% by weight of the recycled carpet.

Blends of polyester thermoplastics and recycled polyester thermoplastics may be used for the practice of this invention. 2. Diols

Diols suitable for use in making the inventive polyester polyols are well known. By “diol,” we mean a linear or branched, aliphatic or cycloaliphatic compound or mixture of compounds having two or more hydroxyl groups. Other functionalities, particularly ether or ester groups, may be present in the diol. In preferred diols, two of the hydroxyl groups are separated by from 2 to 10 carbons, preferably 2 to 5 carbons. Suitable diols include, for example, ethylene glycol, propylene glycol, 1 ,3-propanediol, 1 ,2-butylene glycol, 1 ,3- butylene glycol, 2,3-butanediol, 1 ,4-butanediol, 2-methyl-1 ,3-propanediol, pentaerythritol, neopentyl glycol, glycerol, trimethylolpropane, 3-methyl-1 ,5-pentanediol, 2, 2,4,4- tetrarmethyl-1 ,3-cyclobutanediol, 1 ,3-cyclohexanediol, 1 ,4-cyclohexandiol, 1 ,4- cyclohexanedimethanol, 1 ,3-cyclohexanedimethanol, diethylene glycol, dipropylene glycol, triethylene glycol, 1 ,6-hexanediol, tripropylene glycol, tetraethylene glycol, bisphenol A alkoxylates, polypropylene glycols and polyethylene glycols having a number average molecular weight up to about 400 g/mol, block or random copolymers of ethylene oxide and propylene oxide, and the like, and mixtures thereof. In some preferred aspects, the diol is selected from propylene glycol, 2-rmethyl-1 ,3-propanediol, 3-methyl-1 ,5- pentanediol, neopentyl glycol, diethylene glycol, bisphenol A alkoxylates, polyethylene glycols having a number average molecular weight up to about 200 g/mol, and mixtures thereof. Diethylene glycol, neopentyl glycol, propylene glycol, ethylene glycol, and bisphenol A alkoxylates are particularly preferred. In a preferred aspect, the diol is recycled. For instance, propylene glycol can be recovered from aircraft deicing operations, and ethylene glycol can be recovered from engine coolants or antifreeze.

3. “Partially qlycolvzed”

The thermoplastic polyesters are“partially glycolyzed” or partially digested by reaction with the diol to produce recurring units of the polyester polyol. Partial glycolysis involves selecting conditions effective to convert the thermoplastic polyester to a complex mixture of hydroxy-functional oligomers. A minor proportion of the mixture may include molecules that are well digested, such as bis(hydroxyalkyl) terephthalates. However, the goal of partial glycolysis is to incorporate hydroxyl and carboxylic acid functionality while reducing the molecular weight of the thermoplastic enough to effect a desirable reduction in softening point, melting point, or both. Consequently, the degree of glycolysis needed for a particular application will usually vary. For instance, for a hot-melt adhesive application, a softening point within the range about 40°C to 100°C may be most desirable, whereas for a binder application, a higher softening point within the range of 90°C to 180°C may be more preferred. The skilled person can control the degree of glycolysis by altering reactant selection, diol to thermoplastic polyester ratio, mixing rate, reaction temperature, reaction time, and other factors. Usually, the reaction is performed by heating the thermoplastic polyester, diol(s), and any catalyst at least until the mixture liquefies and particles of the thermoplastic polyester are no longer apparent.

4. Vegetable oil-based hydrophobes

In some aspects, the polyester polyols incorporate 2 to 20 wt.%, preferably 3 to 15 wt.%, of recurring units from one or more vegetable oil-based hydrophobes.

Suitable vegetable oil-based hydrophobes are well known. Examples include dimer fatty acids, oleic acid, ricinoleic acid, tall oil, tall oil fatty acids, tung oil, corn oil, canola oil, soybean oil, sunflower oil, triglycerides or alkyl carboxylate esters having saturated or unsaturated C6-C36 fatty acid units, castor oil, alkoxylated castor oil, saturated or unsaturated C6-C18 dicarboxylic acids or diols, cardanol-based products, recycled cooking oil, branched or linear C6-C36 fatty alcohols, hydroxy-functional materials derived from epoxidized, ozonized, or hydroformylated vegetable oils, fatty esters or fatty acids, hydroxy-functionalized vegetable oils (e.g., “Honey Bee” polyols), maleated polybutadienes, maleic anhydride-grafted polyolefins, hydroxyl or carboxylic acid- terminated polybutadienes, polyfarnesene polyols, and the like, and mixtures thereof. The hydrophobes are well-suited to react with partially glycolyzed thermoplastic polyesters.

Dimer fatty acids are suitable vegetable oil-based hydrophobes. Dimer fatty acids are made by dimerizing unsaturated fatty acids (e.g., oleic acid, linoleic acid, linolenic acid, ricinoleic acid) in the presence of a catalyst, such as a bentonite or montmorillonite clay. Commercially available dimer fatty acids are usually mixtures of products in which the dimerized product predominates. Some commercial dimer acids are made by dimerizing tall oil fatty acids. Dimer fatty acids frequently have 36 carbons and two carboxylic acid groups. They may be saturated or unsaturated. They may also be hydrogenated to remove unsaturation. In a preferred aspect, the dimer fatty acid comprises dimerized oleic acid, trimerized oleic acid, dimerized linoleic acid, trimerized linolelic acid, dimerized linolenic acid, trimerized linolenic acid, or mixtures thereof. Suitable dimer fatty acids include Pripol™ dimer fatty acids (products of Croda) such as Pripol™ 1006, 1009, 1010, 1012, 1013, 1017, 1022, 1025, 1027, 1029, 1036, and 1098; Unidyme™ dimer acids (products of Krayton) such as Unidyme™ 10, 14, 18, 22, 35, M15, and M35; dimer acids available from Emery Oleochemicals, and FloraDyme™ dimer acids from Florachem Corporation. Methods for synthesizing dimer fatty acids suitable for use are also known. Fatty acids having at least one carbon-carbon double bond are dimerized in the presence of a catalyst such as a montmorillonite, kaolinite, hectorite, or attapulgite clay (see, e.g., U.S. Pat. Nos. 2,793,220, 4,371 ,469, 5,138,027, and 6,281 ,373, the teachings of which are incorporated herein by reference; see also WO 2000/075252 and CA 10451 1 ).

Oleic acid is a suitable hydrophobe. Oleic acid is ubiquitous in nature as a fatty acid and is readily available from saponification of vegetable fats and oils.

Ricinoleic acid (12-hydroxy-9-c/s-octadecenoic acid) can be used as the hydrophobe. Castor oil contains 90% or more of ricinoleic acid residues and is a convenient and primary source of the acid.

Tung oil, also called“China wood oil,” is also suitable for use as the hydrophobe.

Tung oil is a triglyceride. The principal fatty acid residues (about 82%) are from alpha- eleostearic acid, a Cie fatty acid with 9 -cis, 1 1 -trans, 13 -trans unsaturation. The other fatty acid residues are from linoleic acid (8.5%), palmitic acid (5.5%), and oleic acid (4%). Consequently, tung oil has ester (glyceride) and olefin functionalities, and compared with other oils, it is highly unsaturated.

Other natural oils such as corn oil, canola oil, soybean oil, sunflower oil, and the like, are suitable hydrophobes. Also suitable are triglycerides or alkyl carboxylate esters having saturated or unsaturated C6-C36 fatty acid units.

Castor oil and alkoxylated castor oils are also suitable as hydrophobes. Castor oils ethoxylated with various proportions of ethylene oxide, for instance 5 to 100 moles of EO per mole of castor oil, are commercially available. Ethoxylated castor oils have ester (glyceride), olefin, and primary hydroxyl functionalities. Examples include Toximul ^® 8241 , Toximul ^® 8242, and Toximul ^® 8244, products of Stepan Company, and the Etocas™ series of ethoxylated castor oils from Croda. Ethoxylated castor oils can also be synthesized using well-known processes by reacting the oil with ethylene oxide in the presence of an alkoxide, Lewis acid, double metal cyanide complex, or other suitable ethoxylation catalyst.

Saturated or unsaturated C6-C18 dicarboxylic acids or diols are suitable for use as hydrophobes. Examples include azelaic acid, nonenedioic acid, sebacic acid, decenedioic acid, dodecanedioic acid, dodecenedioic acid, tetradecanedioic acid, tetradecenedioic acid, hexadecanedioic acid, hexadecenedioic acid, octadecanedioic acid, octadecenedioic acid, and the like, and mixtures thereof. Dicarboxylic acids are generally widely available from commercial sources.

Cardanol-based products can also be used as the hydrophobe. Cardanol, the main constituent of cashew nutshell oil, is an alkylated phenol having a linear C15 unsaturated alkyl chain. By“cardanol-based products,” we mean to include cardanol and products derived from cardanol. Such products may include alkoxylated cardanols, including the hydroxyalkylated compositions described in U.S. Pat. No. 6,229,054, the teachings of which are incorporated herein by reference. Also suitable are“cardanol dimers,” which can be made by joining two cardanol groups using a siloxane linker. In some aspects, Mannich chemistry is used to introduce amine functionality as an attachment to the phenolic rings of the cardanol dimers. Other functionalities, such as epoxy groups, can be introduced if desired. Suitable cardanol-based products, including cardanol dimers, are disclosed in U.S. Pat. Nos. 7,858,725; 7,994,268; 8,263,726; U.S. Pat. Appl. Publ. Nos. 201 1 /01 18495; 201 1/0065947; 201 1/0065883; 201 1 /0065882; and 201 1 /0065832, the teachings of which are incorporated herein by reference.

Recycled cooking oils are also suitable hydrophobes. The cooking oils, which contain vegetable oil mixtures, are collected from restaurants or commercial food preparation facilities. The product may be dark, even after carbon treatment, but its properties are generally consistent with requirements for acceptable polyols. Branched or linear C6-C36 fatty alcohols are suitable hydrophobes. For instance, isostearyl alcohol, a commonly used fatty alcohol available as an article of commerce, is suitable for use.

Hydroxy-functional materials derived from epoxidized, ozonized, or hydroformylated vegetable oils, fatty esters or fatty acids, also commonly known as“bio polyols” or“natural oil polyols” are another category of suitable hydrophobes. These products can be made from fatty esters (including natural oils) or fatty acids in several steps. Some products include a step to epoxidize carbon-carbon double bonds in the fatty ester or fatty acid, followed by a ring-opening step. In other products, unsaturation in the fatty ester or fatty acid is hydroformylated and then hydrogenated to introduce the hydroxyl functionality (see, e.g., D. Babb et al., Polvm. Preprints 48 (2007) 855, PCT Internat. Appl. WO 2006/012344, and U.S. Pat. No. 8,598,297, the teachings of which are incorporated herein by reference). Polyols made by hydrolysis or alcoholysis of epoxidized soybean oil are among the suitable bio-polyols. BiOH ^® polyols supplied by Cargill (e.g., BiOH ^® X-0002) and Agrol ^® polyols from BioBased Technologies are also suitable. The bio-polyol can also be generated“in situ” from a reaction between the glycol and an epoxidized fatty ester or an epoxidized fatty acid (such as epoxidized soybean oil, epoxidized methyl oleate, epoxidized oleic acid, or epoxidized methyl soyate). Suitable bio-polyols include polyols derived from ozonized fatty esters or ozonized fatty acids, such as mixtures obtained by ozonolysis of a natural oil in the presence of a glycol, as is described by P. Tran et al., J. Am. Oil Chem. Soc. 82 (2005) 653. For more examples of suitable bio-polyols, see U.S. Pat. Nos. 6,433,121 ; 8,664,352, U.S. Publ. Nos. 2012/0136169, 201 1/0313124, and 2009/0287007, and PCT Appl. No. W02009/058367, the teachings of which are incorporated herein by reference.

“Honey Bee” polyols, products of MCPU Polymer Engineering, LLC, are another example of hydroxy-functional vegetable oils. These polyols, including their reaction products with coupling agents, such as maleic anhydride, are also suitable hydrophobes. The polyols avoid epoxidiation and ring-opening to make a natural oil polyol by reacting the natural oil with a crosslinker (e.g., diethanolamine) and iodine under conditions effective to introduce primary hydroxyl functionality into the polyol. See, e.g., U.S. Pat. Nos. 8,541 ,536; 8,822,625; and 8,865,854, the teachings of which are incorporated herein by reference.

Other suitable hydrophobes include hydroxyl- or carboxylic acid-terminated polybutadienes (such as those produced by TOTAL Cray Valley), polyfarnesene polyols (such as those produced by TOTAL Cray Valley), maleated polybutadienes (such as those produced by TOTAL Cray Valley). Maleic anhydride-grafted polyolefins such as linear low density polyethylene grafted with maleic anhydride, low density polyethylene grafted with maleic anhydride, polypropylene grafted with maleic anhydride, and high density polyethylene grafted with maleic anhydride (as supplied, e.g., by Eastman Chemical (e.g., Eastman™ G-3003 and Eastman™ G-3015 functionalized polymers) and by Dow Chemical Company under the Amplify ^® mark and LyondellBasell under the Plexar ^® mark).

5. C ₄ -C36 dicarboxylic acid, diester, or anhydride

In some aspects, the polyester polyols incorporate 1 to 5 wt.%, preferably 2 to 4 wt.%, of a C4-C36 dicarboxylic acid, diester, or anhydride (hereinafter also “C4-C36 dicarboxylic acid or derivative”). The C4-C36 dicarboxylic acid or derivative is included to build molecular weight, modify product viscosity, improve compatibility of the polyester polyol with other components of the hot-melt adhesive or binder composition, or for other purposes.

Suitable C4-C36 dicarboxylic acids or derivatives are well known, and many are commercially available. Examples include maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, trirmellitic acid, trimellitic anhydride, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, succinic anhydride, adipic acid, glutaric acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, cyclohexanedicarboxylic acids, 2,5-furandicarboxylic acid, and the like, ester derivatives thereof, and mixtures thereof. Preferred are C4-C12 dicarboxylic acids or derivatives. Commercially available diacid mixtures, such as“DBA” (a mixture of glutaric acid, succinic acid, and adipic acid) are also suitable for use. 6. Polvether polyols

Optionally, the polyester polyols described above are reaction products with one or more polyether polyols. Suitable polyether polyols comprise recurring units of ethylene oxide, propylene oxide, butylene oxides, or combinations thereof. Suitable polyether polyols have average hydroxyl functionalities from about 1 .8 to 8, or from 2 to 6, or from 3 to 5. Many polyether polyols of this type are commercially available from Dow Chemical, BASF, Fluntsman, Covestro, and other suppliers. In one aspect, the polyether polyol is a reactive polyol having primary hydroxyl end groups from ethylene oxide. In another aspect, the polyether polyol has a number average molecular weight within the range of 500 to 8,000 g/mol, or from 1 ,000 to 7,000 g/mol, or from 1 ,900 to 6,700 g/mol. The polyether polyol can be used to modify the softening point, viscosity, or other properties important for performance in hot-melt adhesives, binder compositions, or other end-use applications. Preferred ranges for the polyether polyols can be 0 to 25 wt.%, 1 to 25 wt.%, 1 to 20 wt.%, or 1 to 15 wt.%, wherein the wt.% values are based on the total amount of charged reactants.

7. Lignins or tannins

Optionally, the polyester polyols described above can comprise recurring units from a lignin, a tannin, or a mixture thereof. Suitable lignins include alkali lignins, organosolv lignins, and the like, and mixtures thereof. Organosolv lignins and their mixtures with alkali lignins are preferred. Alkali lignins are generated in the kraft process for paper pulping and are commercially available, for example, from MeadWestvaco. Research quantities of alkali lignins and organosolv lignins can be obtained from Sigma- Aldrich, for example. Larger quantities of alkali lignins are available from kraft plants, which normally burn the lignin for its fuel value. Larger quantities of organosolv lignins may be obtained, for example, from CIMV (France) or Fibria (Canada and Brazil), which operate pilot units for producing organosolv lignins.

The amount of lignin present in the inventive polyols can vary over a wide range. Generally, when a lignin is included, the polyols will comprise 0.1 to 35 wt.%, preferably 1 to 30 wt.%, more preferably 2 to 25 wt.%, of the lignin or its mixture with a tannin. Tannins suitable for use are the polyphenolic materials that occur in plant species. Suitable tannins derive from gallic acid, flavone, or phloroglucinol. Tannins suitable for use have been described in U.S. Pat. Nos. 5,516,338; 6,395,808; 6,624,258; and U.S. Publ. No. 2009/0269378, the teachings of which are incorporated herein by reference. The amount of tannin present in the inventive polyols can vary over a wide range. Generally, when a tannin is included, the polyols will comprise 0.1 to 35 wt.%, preferably 1 to 30 wt.%, more preferably 2 to 25 wt.%, of the tannin or its mixture with a lignin.

8. Hydroxy-functional ketal acid, ester, or amide

Optionally, the polyester polyol comprises recurring units from a hydroxy-functional ketal acid, ester or amide. Suitable hydroxy-functional ketal acids, esters, and amides can be made by reacting oxocarboxylates with a triol, preferably in the presence of an acid catalyst. As used herein, and for convenience,“ketal” refers to either a hydroxy- functional ketal (reaction product of a triol and a ketone) or a hydroxy-functional acetal (reaction product of a triol and an aldehyde).

Suitable oxocarboxylates have a ketone or aldehyde (“oxo”) functionality in addition to a carboxylate (acid, ester, or amide) functionality. The carbonyl groups of the ketone or aldehyde may or may not be separated by one or more carbons from the acid, ester, or amide carbonyl. Suitable oxocarboxylates include keto acids, keto esters, keto amides, aldo acids, aldo esters, and aldo amides.

Suitable keto acids include, for example, pyruvic acid, acetoacetic acid, levulinic acid, oxaloacetic acid, 2-ketobutyric acid, 2-ketovaleric acid, homolevulinic acid, 4- acetylbutyric acid, 3-ketohexanoic acid, 5-acetylvaleric acid, and the like.

Suitable keto esters are lower (e.g., C1-C10, preferably C1-C6) alkyl or alkenyl esters of the keto acids. Suitable alcohols used for making the esters from the keto acids include, for example, methanol, ethanol, 1 -propanol, 2-propanol, 1 -butanol, 2-butanol, 1 - hexanol, and the like, with methyl esters and ethyl esters being most preferred. Thus, suitable keto esters include, for example, ethyl pyruvate, ethyl acetoacetate, methyl acetoacetate, ethyl levulinate, ethyl 4-acetylbutyrate, and the like.

Suitable keto amides are reaction products of keto acids with ammonia, primary amines, or secondary amines, preferably secondary amines. Suitable amines for making the amides from the keto acids include, for example, methylamine, ethylamine, n- butylamine, cyclohexylamine, dimethylamine, diethylamine, di-n-butylamine, pyrrolidine, piperidine, and the like.

Suitable aldo acids include, for example, 2-oxoacetic acid, 3-oxopropanoic acid, 2-methyl-3-oxopropanoic acid, 4-oxobutanoic acid, 2-methyl-4-oxobutanoic acid, 3- methyl-4-oxobutanoic acid, 5-oxopentanoic acid, 2-methyl-5-oxopentanoic acid, 3- methyl-5-oxopentanoic acid, 4-methyl-5-oxopentanoic acid, 6-oxohexanoic acid, 5- methyl-6-oxohexanoic acid, and the like.

Suitable aldo esters are lower (e.g., C1-C10, preferably C1-C6) alkyl or alkenyl esters of the aldo acids. Suitable alcohols used for making the esters from the aldo acids include, for example, methanol, ethanol, 1 -propanol, 2-propanol, 1 -butanol, 2-butanol, 1 - hexanol, and the like, with methyl esters and ethyl esters being most preferred. Thus, suitable aldo esters include, for example, ethyl 3-oxopropanoate, methyl 4-oxobutanoate, ethyl 6-oxohexanoate, and the like.

Suitable aldo amides are reaction products of aldo acids with ammonia, primary amines, or secondary amines. Suitable amines for making the amides from the aldo acids include, for example, methylamine, ethylamine, n-butylamine, cyclohexylamine, dimethylamine, diethylamine, di-n-butylamine, pyrrolidine, piperidine, and the like.

For additional examples of suitable oxocarboxylates, see U.S. Pat. Nos. 8,604,077; 8,546,519; and 8,053,468, the teachings of which are incorporated herein by reference.

The hydroxy-functional ketal acids, esters, and amides can be made by reacting oxocarboxylates with a triol. Suitable triols have are relatively low molecular weight compounds having three hydroxyl groups. Examples include glycerol, trimethylolpropane, trimethylolethane, 1 ,2,4-butanetriol, 1 ,2,5-trihydroxypentane, and the like. Glycerol, trimethylolpropane, and trimethylolethane are readily available and are preferred for some aspects. For additional examples of suitable triols, see U.S. Pat. Nos. 8,604,077; 8,546,519; and 8,053,468, the teachings of which are incorporated herein by reference.

The reaction of an oxycarboxylate and a triol, in some aspects in the presence of an acid catalyst, provides a hydroxy-functional ketal acid, ester, or amide. Suitable acid catalysts for this reaction are well known and include mineral acids, organic acids, solid acids, organic clays, and the like. Organic sulfonic acids, such as p-toluenesulfonic acid, are particularly preferred.

In some aspects, the hydroxy-functional ketal acid, ester, or amide has the general structure:

wherein R ¹ is hydrogen, methyl, ethyl, or hydroxymethyl; R ² is hydrogen, C1 -C24 alkyl, or C1 -C24 alkenyl; Z is a C1 -C6 alkylene group or a C1 -C6 alkylene group substituted with a C1 -C24 alkyl or alkenyl group; X is OR ³ or NR ⁴ R ⁵ ; R ³ is hydrogen or a C1 -C12 alkyl group; each of R ⁴ and R ⁵ is independently a C1 -C12 alkyl group; m is 0 or 1 ; and n is 0 or 1 . In some aspects, X is preferably OR ³ , and R ³ is a C1 -C12 alkyl group.

Hydroxy-functional ketal esters are preferred. Suitable hydroxy-functional ketal esters include, for example, ethyl levulinate glycerol ketal, methyl levulinate trimethylolpropane ketal, ethyl levulinate trimethylolpropane ketal, ethyl pyruvate glycerol ketal, ethyl pyruvate triethylolpropane ketal, ethyl acetoacetate glycerol ketal, and the like. In some aspects, levulinate glycerol ketals are preferred hydroxy-functional ketal esters.

In some aspects, the molar ratio of ketal acid, ester or amide recurring units to thermoplastic polyester recurring units is within the range of 0.5 to 2.0, or 0.6 to 1.8, or 0.7 to 1 .6.

9. Digestible polymers

Digestible polymers contain a functional group selected from an ester, amide, ether, carbonate, urea, carbamate, glycoside, and isocyanurate, or combinations thereof. “Digestible polymer” as used herein, and as described in more detail in U.S. Publ. Nos. 2016/0052844 and 2017/0029561 , the teachings of which are incorporated herein by reference, refers to a polymer component capable of being broken down or degraded into smaller polymeric, oligomeric, or monomeric components and/or trans-reacting with ester groups during the process of glycolysis. Digestible polymers can be obtained from recycled polymers and waste streams, including synthetic plastics and natural waste materials such as avian feathers or wool. In fact, in view of green chemistry and sustainability considerations, it is highly desirable to use digestible polymers from such sources. The digestible polymer may further be obtained from virgin or newly manufactured sources. The latter choice makes sense in cases where the additional performance benefit obtained by digesting the newly manufactured polymer provides a value-added benefit to the resulting polyester polyol product.

10. Preparation of partially qlvcolyzed thermoplastic polyesters

In some aspects, the thermoplastic polyester and diol are first heated, optionally in the presence of a catalyst, to give a partially glycolyzed intermediate. This intermediate will commonly be a mixture of diol reactant, diol(s) generated from the thermoplastic polyester, terephthalate oligomers, and other glycolysis products. In batch reactors, heating is advantageously performed at temperatures within the range of 80°C to 240°C, preferably 100°C to 230°C, more preferably 130°C to 230°C, and most preferably 160°C to 225°C. Reaction temperatures can be significantly higher in continuous reaction processes, e.g., single-screw or twin-screw extrusion, for which residence times are generally much shorter. Thus, preferred reaction temperatures with extrusion or similar processes with short residence times range from 130°C to 320°C, from 150°C to 300°C, or from 200°C to 260°C. Reaction conditions are controlled to ensure partial glycolysis of the thermoplastic polyester, usually targeting a particular hydroxyl number, acid number, ring-and-ball softening point, or some combination of desired properties.

Catalysts suitable for making the partially glycolyzed intermediate are well known (see, e.g., K. Troev et al. , J. Appl. Polym. Sci. 90 (2003) 1 148). In particular, suitable catalysts comprise titanium, antimony, germanium, zirconium, manganese, or other metals. Specific examples include titanium alkoxides (e.g., tetrabutyl titanate or tetraisopropyl titanate), titanium(IV) phosphate, zirconium alkoxides, lead acetate, cobalt acetate, rmanganese(ll) acetate, antimony trioxide, germanium oxide, or the like, and mixtures thereof. Catalysts that do not significantly promote isocyanate reaction chemistries or other undesirable side reactions are preferred; in this respect, preferred catalysts exclude zinc acetate, an otherwise popular catalyst choice in some literature. As is discussed in more detail below, catalysts comprising titanium, particularly titanium alkoxides, are especially preferred. The amount of catalyst used is typically in the range of 0.005 to 5 wt.%, preferably 0.01 to 1 wt.%, more preferably 0.02 to 0.7 wt.%, based on the total amount of polyol being prepared. The molar ratio of diol to thermoplastic polyester recurring units is preferably less than 0.8, and in some aspects is within the range of 0.1 to 0.5 or from 0.1 to 0.3.

In some aspects, a polyester polyol is produced by a process which comprises two steps. First, 65 to 90 wt.% of a thermoplastic polyester is reacted with 2 to 15 wt.% of a diol at a temperature within the range of 125°C to 320°C in the presence of a catalyst, preferably a catalyst comprising titanium, to produce a partially glycolyzed intermediate. This intermediate is then reacted with 2 to 20 wt.% of a vegetable oil-based hydrophobe and 1 to 5 wt.% of a C ₄ -C36 dicarboxylic acid, diester, or anhydride at a temperature within the range of 125°C to 320°C to produce a polyester polyol having a ring-and-ball softening point as measured by ASTM D-36 of at least 40°C. The wt.% values are based on the total amount of charged reactants. In preferred aspects, the polyol is subsequently cooled, and the resulting pellet, sheet, or formed article is then pulverized or pelletized. As used in this application,“pulverized” refers to a solid polyol product that has been comminuted, chopped, ground, or otherwise reduced in size to generate a powder, flake, pastille, granule, pellet, or other similar form.

In other aspects, a polyester polyol is produced by a process which comprises reacting 65 to 90 wt.% of a thermoplastic polyester, 2 to 15 wt.% of a diol, 2 to 20 wt.% of a vegetable oil-based hydrophobe, and 1 to 5 wt.% of a C4-C36 dicarboxylic acid, diester, or anhydride in a single-screw or twin-screw extruder at one or more temperatures within the range of 125°C to 320°C to produce an extrudate. The wt.% values are based on the total amount of charged reactants. In preferred aspects, the extrudate is subsequently cooled and pulverized or pelletized.

1 1 . Properties of the polyester polyols

In some aspects, the polyester polyols have number-average molecular weights as measured by gel permeation chromatography (GPC) within the range of 1 ,000 to 10,000 g/mol or within the range of 1 ,200 to 5,000 g/mol. In some aspects, the polyols have hydroxyl numbers as measured by ASTM E- 222 within the range of 10 to 50 mg KOH/g, or from 28 to 45 mg KOH/g.

In other aspects, the polyols have a ring-and-ball softening point as measured by ASTM D-36 of at least 40°C, or within the range of 55°C to 200°C, from 70°C to 190°C, or from 90°C to 180°C.

In some aspects, the polyester polyols have acid numbers as measured by ASTM D4662-15 within the range of 10 to 50 mg KOH/g or from 20 to 40 mg KOH/g.

B. Hot-melt adhesive compositions

Polyester polyols produced as described above are useful as components of hot- melt adhesives.

In one aspect, the hot-melt adhesive composition comprises 1 to 75 wt.% of a polyester polyol. The polyol comprises a partially glycolyzed reaction product of 65 to 90 wt.% of a thermoplastic polyester and 2 to 15 wt.% of a diol. Optionally, the polyol further comprises 2 to 20 wt.% of a vegetable oil-based hydrophobe, 1 to 5 wt.% of a C4-C36 dicarboxylic acid, diester, or anhydride, or both. The wt.% values are based on the total amount of charged reactants. The molar ratio of diol to thermoplastic polyester recurring units is less than 0.8, and the polyol has a ring-and-ball softening point as measured by ASTM D-36 within the range of 55°C to 200°C.

In another aspect, the hot-melt adhesive composition comprises 1 to 75 wt.% of a polyester polyol. The polyol comprises recurring units of 65 to 90 wt.% of a thermoplastic polyester; 2 to 15 wt.% of a diol; 2 to 20 wt.% of a vegetable oil-based hydrophobe; and 1 to 5 wt.% of a C4-C36 dicarboxylic acid, diester, or anhydride. The wt.%> values are based on the total amount of charged reactants. In this aspect, the polyol has a hydroxyl number as measured by ASTM E-222 within the range of 10 to 50 mg KOH/g, an acid number as measured by ASTM D4662-15 within the range of 10 to 50 mg KOH/g, and a ring-and-ball softening point as measured by ASTM D-36 of at least 40°C.

In some aspects, the polyester polyol is the principal component of the hot-melt adhesive. In other aspects, the polyester polyol is used primarily as a tackifier in combination with other adhesive components. The polyester polyol can be used in the production of a wide variety of hot-melt adhesives, including those based on ethylene-vinyl acetate (EVA) copolymers, polyolefins, polyamides, polyesters, polycarbonates, polyurethanes, or other thermoplastic compositions.

In a preferred aspect, the hot-melt adhesive is an EVA formulation that includes a wax (e.g., paraffinic wax, polyamide wax, Fisher-Tropsch wax) and a tackifier. In preferred aspects, the compositions include a paraffinic wax, an EVA copolymer, and a tackifier, often in roughly equal amounts by weight.

Suitable tackifiers include rosin esters, polyterpenes, terpene-phenol polymers, hydrocarbon resins, and the like. The polyester polyols described herein can be used to replace some or all of the conventional tackifier.

In one aspect, the invention relates to a hot-melt adhesive composition comprising 20 to 50 wt.% of a wax, 20 to 50 wt.% of an ethylene vinyl acetate (EVA) copolymer, and 20 to 50 wt.% of a tackifier comprising a polyester polyol as described above. As indicated above, the tackifier may further comprise a hydrocarbon resin, a polyterpene, a terpene-phenol resin, a rosin ester, or a mixture thereof.

C. Binder compositions

The inventive polyester polyols are useful for various types of binder compositions. In some aspects, the binder composition comprises 1 to 75 wt.% of a polyester polyol as described above.

The binder compositions include, for example, asphalt compositions, wood composites, textiles, artificial fireplace logs, molded composites from agricultural wastes (e.g., plant fibers, wood flour, ground tree bark, shell flour, sisal, starch, sawdust, grain straws, hemp, bagasse, cellulose fibers, palm kernel shells, nutshells, rice husks, jute, tomato skins, or other biomass), molded composites from synthetic polymer wastes (tire rubber crumbs or dust; ground polyurethane or polyisocyanurate foams; other synthetic polymer scrap; or synthetic polymer fibers such as polyamides, polyesters, aramids, polyvinyl alcohol fibers, or synthetic silk), and the like, and combinations thereof. 1 . Reinforced or filled composites

In another aspect, the inventive polyester polyols are used to prepare inorganic particulate-reinforced or filled composites. Suitable inorganic fillers or reinforcing particulates include fiberglass, recycled pulverized glass particles, mica flake or powder, ceramic fibers, talc, calcium carbonate, barium sulfate, wollastonite, carbon fibers, magnesium oxide, magnesium hydroxide, apatite, titanium dioxide, antimony oxide, clays, potassium titanate fiber, rock wool, kaolin, lignite fly ash, fumed silica, silica, aluminum oxide, zinc oxide, aluminum hydrate, graphite, calcium sulfate, phosphates, montmorillonite, feldspar, boron, carbon nanotubes, silver dust, carbon black, graphite fibers, graphite flakes, and the like, and combinations thereof.

2. Asphalt binder compositions

As used herein,“asphalt binder” and“bituminous binder” refer to a combination of bitumen and, optionally, other components. The other components can include polyester polyol additives produced from partially glycolyzed thermoplastic polymers (as described herein), elastomers, non-bituminous binders, adhesion promoters, softening agents, rejuvenating agents, polyphosphoric acids, or other suitable additives. Useful elastomers include, for example, ethylene-vinyl acetate copolymers, polybutadienes, ethylene- propylene copolymers, ethylene-propylene-diene terpolymers, butadiene-styrene block copolymers, styrene-butadiene-styrene (SBS) block terpolymers, isoprene-styrene block copolymers and styrene-isoprene-styrene (SIS) block terpolymers, or the like. The rubber components can improve low-temperature fatigue performance of asphalt binder compositions.

“Bitumen” refers to a mixture of viscous organic liquids or semi-solids from crude oil that is black, sticky, soluble in carbon disulfide, and composed primarily of condensed aromatic hydrocarbons. Alternatively, bitumen refers to a mixture of maltenes and asphaltenes. Bitumen may be any conventional type of bitumen known to the skilled person. The bitumen may be naturally occurring. It may be crude bitumen, or it may be refined bitumen obtained as the bottom residue from vacuum distillation of crude oil, thermal cracking, or hydrocracking. “Aggregate” is particulate mineral material suitable for use in asphalt paving. It generally comprises sand, gravel, crushed stone, and slag. Any conventional type of aggregate suitable for use in asphalt can be used. Examples of suitable aggregates include granite, limestone, gravel, and mixtures thereof.

“Asphalt pavement” or“asphalt concrete” refers to a combination of aggregate, asphalt binder, and other materials that is used for road surfaces, shoulders, bridge abutments, and similar structures.

Asphalt binders are manufactured to achieve a variety of different performance grades under the“Superpave” system. High temperatures can range from 46°C to 82°C, while low temperatures can range from -10°C to -46°C. A“PG 58-28” binder, for instance, can provide optimum performance at temperatures within the range of -28°C and 58°C.

Various analytical methods are used to evaluate asphalt binder properties. With dynamic shear rheometry (DSR), for example, the impact of additives on the dynamic shear properties of an asphalt binder composition can be measured. DSR is a well-known technique in the field and is discussed elsewhere (see, e.g., E. Ray Brown et al., Hot Mix Asphalt Materials, Mixture Design, and Construction, 3d ed. (2009), Chapter 2, pp. 88- 97). In general, rutting resistance (i.e., performance of the asphalt binder at relatively high temperatures) is improved for relatively high values of G ^* (complex modulus) and relatively low values of d (phase angle).

In one aspect, the invention relates to an asphalt binder composition. The composition comprises a bituminous binder and from 0.1 to 20 wt.%, preferably 0.5 to 10 wt.%, of an additive comprising a polyester polyol as described above. The amount of additive is based on the combined amounts of bituminous binder and polyol.

In other aspects, the binder composition comprises a PG 58-28 binder, and the dynamic shear, that is, the value of G7sin d at 10 rad/s, measured at 58°C is boosted by at least 20% by incorporation of the additive.

In a particular aspect, the polyester polyol used in the asphalt binder composition comprises recurring units of 65 to 90 wt.% of a thermoplastic polyester; 2 to 15 wt.% of a diol; optionally, 2 to 20 wt.% of a vegetable oil-based hydrophobe; and optionally, 1 to 5 wt.% of a C ₄ -C36 dicarboxylic acid, diester, or anhydride. The wt.% values are based on the total amount of charged reactants. In this aspect, the molar ratio of diol to thermoplastic polyester recurring units is less than 0.8, preferably from 0.1 to 0.5, and the polyol has a ring-and-ball softening point as measured by ASTM D-36 within the range of 55°C to 200°C.

In another particular aspect, the polyester polyol used in the asphalt binder composition comprises recurring units of 65 to 90 wt.% of a thermoplastic polyester; 2 to 15 wt.% of a diol; 2 to 20 wt.% of a vegetable oil-based hydrophobe; and 1 to 5 wt.% of a C4-C36 dicarboxylic acid, diester, or anhydride. The wt.% values are based on the total amount of charged reactants. In this aspect, the polyester polyol has a hydroxyl number as measured by ASTM E-222 within the range of 10 to 50 mg KOH/g, an acid number as measured by ASTM D4662-15 within the range of 10 to 50 mg KOH/g, and a ring-and- ball softening point as measured by ASTM D-36 of at least 40°C.

In other aspects, the invention includes asphalt concrete compositions comprising aggregate and the asphalt binder compositions described above. The following examples merely illustrate the invention; the skilled person will recognize many variations that are within the spirit of the invention and scope of the claims.

Preparation of Polyols A-K (general procedure)

In a typical example, a reactor equipped with an overhead mixer, condenser, heating mantle, thermocouple, and nitrogen inlet is charged with recycled PET (85.8 wt.%), diethylene glycol (14.2 wt.%, 0.30 moles of DEG per mole of rPET), and monobutyltin oxide (0.1 wt.%). The mixture is heated to 225°C with slow mixing under a flow of nitrogen. The reaction mixture is held at 225°C until no rPET particles remain, and the partial glycolysis is considered complete. See Table 1 for details.

Preparation of Polyols L-T (general procedure)

The procedure for preparing Polyols A-K is generally followed to produce a glycolyzed thermoplastic intermediate by first reacting the recycled PET with diethylene glycol (DEG) at a low molar ratio of 0.5 moles DEG/mole of rPET. The intermediate is then reacted with 10-20 wt.% of a hydrophobe or other modifier as indicated in Table 2. As shown in the table, the resulting polyester polyols have ring-and-ball softening points within the range of 150°C to 190°C.

Preparation of Polyols U-X

Polyols U, V, and W are prepared as described above using rPET (78.0 wt.%), diethylene glycol (12.0 wt.), and lignin, fumaric acid, or succinic acid (10.0 wt.%). The products have ring-and-ball softening points from 171 °C to 183°C. See Table 2A.

Polyol X is prepared from rPET (68.9 wt.%), glycerol (16.1 wt.%), and chicken feather meal (15.0 wt.%) generally as described earlier. The product has a ring-and-ball softening point of 71 °C (Table 2A).

Preparation of Polyol Y

A 1 -L flask equipped with temperature probe, heating mantle, temperature controller, nitrogen inlet, mechanical stirrer, and short-path condenser is charged with Polyol CC (31 1 g, 85 wt.%; ring-and-ball softening point: 172°C; viscosity at 190°C: 130cP) and Pluracol ^® 2100 reactive polyether triol (product of BASF, 45.9 g, 15 wt.%). The charged materials are heated to 225°C and reacted for 4 h. Thereafter, the product is poured into an aluminum container, cooled, and broken into pieces. The resulting polyol has a ring-and-ball softening point of 168°C. Viscosity (190°C): 2600 cP. Acid value: 8.6 mg KOH/g. Hydroxyl value (calculated): 35 mg KOH/g.

Preparation of Polyols AA-NN

Polyols AA-NN are generally prepared as described below with adjustments to the reactants and amounts as indicated in Tables 3 and 4.

In one example, a 2-L reactor equipped with an overhead mixer, condenser, heating mantle, thermocouple, and nitrogen inlet is charged with recycled PETG (282 g, 18.8 wt.%), neopentyl glycol (1 13 g, 7.5 wt.%), and monobutyltin oxide (1 .5 g, 0.1 wt.%). The mixture is heated to 225°C with slow mixing under a flow of nitrogen. The reaction mixture is held at 225°C until no rPETG pellets remain. Once the solution is clear and homogeneous, rPET (847.8 g, 56.5 wt.%) is added in four separate portions. The reaction continues until no rPET pellets present, and the partial glycolysis is considered complete. The condenser is replaced with a vigreux column, short-path distillation head, and receiver. The mixture is cooled to 150°C. T all oil fatty acid (21 1 .8 g, 14.1 wt.%) is added by addition funnel. The mixture is heated with stirring under nitrogen flow to 205°C, and the condensation reaction is allowed to continue for six hours. When water removal is complete, the mixture is cooled to 160°C. Maleic anhydride (43.8 g, 2.9 wt.%) is added by addition funnel. The reaction mixture is held at 160°C for one hour, after which the reaction is complete. The hot mixture is poured onto a foil-lined tray to cool and solidify.

Propylene glycol or trimethylolpropane replaces some or all of the neopentyl glycol in some examples (see Tables 3 and 4). In one example, decanoic acid is used instead of tall oil fatty acid as the hydrophobe. In other examples, phthalic anhydride or trirmellitic anhydride is used in place of some or all of the maleic anhydride. In some examples, titanium(IV) butoxide is used instead of monobutyltin oxide.

Ring-and-ball softening points

Softening points are determined by melting a sample in a microwave oven, allowing it cool, and then testing its ring-and-ball softening point by ASTM D-36 using a Matest Softmatic™ automatic ring-and-ball tester. The softening point can be influenced, dramatically in some instances, by allowing the polyol samples to cool slowly and crystallize over a longer time period. For example, Polyol CC, when allowed to slowly crystallize over a period of weeks, had a ring-and-ball softening point of 169°C. However, when the sample is melted and then allowed to solidify more rapidly, its ring-and-ball softening point was much lower (58°C).

Thus, in some aspects, particularly where a lower softening point is desired, it may be desirable to include a crystallization inhibitor such as a bisphenol alkoxylate, bisphenol polycarbonate, sulfonyl diphenol, sulfonyl diphenol alkoxylate, or other crystallization inhibitor. For these and other examples of suitable crystallization inhibitors, see WO 2016/168043, the teachings of which are incorporated herein by reference.

Dynamic shear of asphalt binder compositions

Asphalt binder compositions are made by combining 1 to 7 wt.% of the inventive polyester polyol additives with a performance-grade (PG 58-28 from Suncor Energy) binder. Dynamic shear rheometry (DSR) and test method AASHTO T 315 (“Standard Method of Test for Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer”) are used to measure dynamic shear (G7sin d at 10 rad/s) in kPa. Samples are mixed at 380°F (193°C) prior to testing to ensure homogeneity.

Unoptimized results appear in Table 5. As shown in the table, the dynamic shear value usually increases when the polyester polyol additive is included when compared with an unmodified PG 58-28 binder. Increased values for dynamic shear should translate to improved high-temperature performance of the asphalt binder.

Low-temperature performance (specifically, creep stiffness) of a limited number of samples is evaluated using bending beam rheometry (BBR). These results show no significant change from the control, indicating that the polyol additives can improve high- temperature performance without an adverse impact on low-temperature properties.

Preparation and testing of hot-melt adhesives

Paraffin wax (HP 6020, product of Hase) is placed in an 80°C oven until molten.

A sample (20 g) is weighed into a 1/4 pint can and placed on a hot plate equipped with an overhead mixer and thermometer. The hot plate is set to 100°C. Ethylene-vinyl acetate copolymer (20 g, Evathane ^® 18-150, product of Arkema) is added over 5 min. and is allowed to melt into solution. After no EVA pellets remain, a polyol sample (20 g of Polyol AA, BB, or CC; see Table 3) or Pexalyn ^® 9100 tackifier (product of Pinova) is added slowly in pea-sized pieces over 10 min. Mixing continues until no polyol pellets are apparent.

When the hot-melt adhesive is homogeneous, a sample is applied via tongue depressor to a 1” x 1” square on a 1” x 4” substrate. The substrates tested include untreated polyethylene, ABS resin, cardboard, and polycarbonate. The coated substrate is overlaid with another substrate of the same material to form a 1” x 1” adhesive bond. Binder clips are applied to each side of the substrate to ensure good contact between the layers. The substrates cool under ambient conditions (25°C, 50% relative humidity) for 2 h or 24 h. When curing is complete, the samples are tested for lap shear strength using an Instron tester according to ASTM D1002. Performance at the 2-h mark is a measure of green strength. Performance at the 24-h mark presumes a complete curing opportunity. Results appear in Table 6.

As shown in the preliminary screening experiments summarized in Table 6, the hot-melt adhesives based on the polyols bond more readily to the more porous cardboard substrate than to any of the polymer substrates (ABS, polycarbonate, or polyethylene) and develop green strength within 2 h on cardboard. The polyol-based HMAs have improved green strength in bonding to cardboard compared with the HMA that contains Pexalyn ^® 9100, a thermoplastic pentaerythritol rosin ester tackifier (product of Pinova). Not surprisingly, overall better performance is achieved with a fully formulated commercial glue stick.

Additional hot-melt adhesive examples: PG-PET Polyol as an Additive

Polyol CC (prepared from partially glycolyzed PET, neopentyl glycol, TOFA, and maleic anhydride) is combined in various proportions with a commercial polyamide hot- melt adhesive (Ad Tech 700). Half-inch chunks of Ad Tech 700 hot-melt adhesive are melted in a steel beaker on a hotplate set at 250°C and the molten product is stirred mechanically. The desired amount (10 wt.% or 30 wt.%) of gravel-sized pieces of Polyol CC is introduced slowly into the beaker while the mixture is held at 180°C to 210°C. After about 10 minutes, the liquid mixture becomes homogeneous. The resulting hot-melt adhesives are cooled and stored until needed. Ring-and-ball softening points: Ad Tech 700: 142°C. With 10 wt.% of Polyol CC: 135°C. With 30 wt.% of Polyol CC: 137°C.

Test procedure

The ability of a hot melt adhesive to bond to polyvinyl chloride, polycarbonate, or aluminum substrates is evaluated.

Enough test substrate panels are obtained to allow testing in triplicate for each composition. Panels are cleaned with isopropyl alcohol, and a X 1” square of polyethylene is glued with hot-melt adhesive to one end of each test panel. The affixed polyethylene squares are used to align the substrate in the testing apparatus.

Steel containers of hot-melt adhesive to be tested are equilibrated in a 205°C. oven, then removed immediately prior to application. A sample of the hot-melt adhesive is applied evenly using a wooden applicator to a 1” x 1” area to the substrate on the opposite side of the polyethylene square. Another substrate piece is pressed together with the coated sample and the halves are clipped together. This process is repeated three times for each of the three substrate types.

After 1 hour of hold time, three specimens of each type are subjected to lap shear testing according to ASTM D1002. Vertically suspended test specimens are pulled apart using an MTS tensile tester at 12 in/min using a 10 kN load cell. A control sample utilized only Ad Tech 700 adhesive to bond the substrates. Results appear in Table 7. As shown in the Table, including 10 wt.% of Polyol CC as an additive in the commercial hot-melt adhesive can improve lap shear strength and/or promote a more desirable failure mode.

The preceding examples are meant only as illustrations; the following claims define the inventive subject matter.