Phthalic anhydride based polyester-ether polyols and urethane prepolymers produced therefrom

[0002] 1. Field of the Invention

[0003] Disclosed are polyester-ether polyols and methods for producing such polyester-ether polyols, along with urethane prepolymers and methods for producing urethane prepolymers comprising the polyester-ether polyols. Such polyols and urethane prepolymers are useful in the preparation of urethane foams and/or non-foam urethanes, wherein the polyester-ether polyol is either the primary polyol component or is utilized in combination with conventional auxiliary polyester- and/or polyether-based polyols. The invention further relates to urethane foam and non-foam urethane compositions such as coatings, adhesives, sealants, and elastomers, which may be prepared utilizing the polyester-ether polyols and/or the urethane prepolymers derived therefrom. The polyols of the instant invention are preferably the reaction product of phthalic anhydride and diethylene glycol, to produce an intermediate polyester polyol, which is subsequently reacted with an alkylene oxide, e.g., propylene oxide, to produce the subject polyester-ether polyols. These polyester-ether polyols impart greatly improved solubility and compatibility to or with mixtures of known alkylene oxide polyols (e.g., polypropylene oxide based polyether polyols) and polyester polyols. The polyester-ether polyols of the instant invention are desirably of lower viscosity than precursor polyester polyols and are generally soluble in either polyester- and/or polyether-based polyols.

[0004] 2. Description of the Related Art

[0005] Desirable physical properties of non-foam polyurethane coatings, adhesives, sealants and elastomers (CASE) include, among others, durability, flexibility, rigidity, hardness, toughness, resistance to abrasion, ability to bond to various substrates, and resistance to chemicals; one of the most desirable properties is hydrolytic stability. Coatings, adhesives, sealants and elastomers which are not resistant to hydrolysis undergo chain scission and gradual degradation of the other physical properties. Desirable properties of finished urethane foams include beneficial insulation characteristics and flame retardency. Industrial polyurethanes are generally made from the reaction of isocyanates/polyisocyanates and materials with multiple hydroxyl moieties (“polyols”). In many foam, adhesive and coatings formulations, polyols comprise the majority of the formulation weight, so that the final product properties are influenced mostly by the polyols.

[0006] Of the commercially available polyols, polyether- and polyester-containing materials are dominant. Polyether polyols are usually based on propylene oxide, ethylene oxide or tetrahydrofuran. These typically exhibit very good resistance to hydrolysis, which is an important requirement of many adhesives and coatings. However, polyether polyols promote adhesion to a very limited variety of substrates. In contrast, polyester polyols generally promote adhesion to more types of surfaces but are more susceptible to hydrolysis. Typically, a polyester molecule is hydrolyzed to an acid and alcohol as shown below. The hydrolysis may be acid or base catalyzed.

[0007] The deleterious consequence of such hydrolysis in a polyurethane material is the loss of desirable physical properties, as hydrolysis gives undesirable products with lower molecular weight.

[0008] In addition, polyester polyols are utilized in both foam and non-foam formulations to improve physical properties such as toughness, tensile and flexural strength, durometer hardness, solvent resistance, and thermal properties. Urethane coatings, and other applications, based on polypropylene oxide polyols and toluene diisocyanate have found limited applications, i.e. indoors only, as also they contain contaminant ether linkages which are readily prone to oxidative degradation. CASE materials derived from polyester polyols, such as those prepared by the condensation of an aliphatic dicarboxylic acids and poly alcohols, are widely used indoors and outdoors. Their primary function in finished CASE materials has been to enhance abrasion resistance. While these CASE materials possess better durability than those based on polypropylene oxide polyols and toluene diisocyanate, they also contain ether groups that undergo oxidative degradation.

[0009] Aliphatic polyester polyols, which contain ether linkages and/or ester linkages have found wide spread use in CASE, as additives which can provide improved bonding and durability. These materials are generally based on caprolactone or adipic acid backbones. One of the more widely used commercial polyester polyols is based on polycaprolactone and sold under the trade name Tone® (Union Carbide Corp.). This polyester polyol is the product of the homopolymerization of caprolactone with a hydroxyl containing compound as an initiator, such as a diol, to form polycaprolactone polyols. These polyester polyol materials are hydrolytically stable, resistant to yellowing, display excellent abrasion, chemical and impact resistance, they provide excellent resistance to oxidative degradation, and are considered to be the leaders of the commercial products which are currently available. However, such materials are generally of high molecular weight (i.e., 1000 g/mol), they are solids at about 25° C. which require heating (to about 60° C.) prior to use and they are therefore generally more difficult to formulate with as compared to lower melting, lower viscosity polyols.

[0010] Aliphatic polyester polyols based on adipic acid are prepared by the condensation of adipic acid and a diol, such as 1,6-hexanediol, as shown below:

[0011] HO₂C—(CH₂)₄—CO₂H+HO—(CH₂)₆—OH→HO[—(CH₂)₆—OOC—(CH₂)₄—COO—](CH₂)₆—OH

[0012] These materials are well known to undergo hydrolytic degradation at the ester linkage cites of the molecule. However, the materials have the advantage of a low manufacturing cost, as compared to Tone® type materials, which is favorable from a consumer point of view.

[0013] Polyester polyols derived from phthalic anhydride (PA) and low molecular weight diols are reported in U.S. Pat. No. 4,644,027 to Magnus et al., issued Feb. 17, 1987 and U.S. Pat. No. 4,644,047 to Wood, issued Feb. 17, 1987, for the production of cellular polyurethane and polyurethane/polyisocyanurates. Polyester polyols derived from PA and neopentyl glycol have been reported in U.S. Pat. No. 4,390,688 to Walz et al., issued Jun. 28, 1983. These materials are described as water dilutable polyesters with good resistance to xylene and dilute caustic solutions. PA polyester polyols have been used in polyurethane/polyisocyanurate rigid foams to impart low thermal conductivity, to lower cost and to lower blowing agent usage as reported in U.S. Pat. No. 4,791,148 to Riley et al., issued Dec. 13, 1988; U.S. Pat. No. 4,888,365 to Riley et al., issued Dec. 19, 1989 and U.S. Pat. No. 5,164,422 to Londrigan et al., issued Nov. 17, 1992. The PA based polyester polyols have been used in the preparation of urethane-modified isocyanurate foam as reported in U.S. Pat. No. 4,544,679 to Tideswell et al., issued Oct. 1, 1985.

[0014] Rigid foams have incorporated PA-based polyester polyols and perfluorinated hydrocarbons to enhance the thermal insulating properties of the foam, as reported in U.S. Pat. No. 4,981,879 to Snider, issued Jan. 1, 1991 and EP 394736 A2, Snider et al., Oct. 31, 1990. The preparation of urethane prepolymers utilizing conventional polyester and polyether polyols is disclosed in U.S. Pat. No. 5,021,507 to Stanley et al., issued Jun. 4, 1991, and more recently in U.S. Pat. No. 5,863,980 to Choi et al., issued Jan. 26, 1999.

[0015] As mentioned above, both polyester-based and polyether-based polyols have their respective beneficial properties and drawbacks/limitations. Additionally, and perhaps most importantly, polyether and polyester polyols are generally not compatible with each other, i.e., they are often not readily soluble or miscible, and therefore are not readily capable of being employed as a mixture for use in any particular application. An ideal polyol would have the desirable properties exhibited by both ester- and ether-based polyols, with limited disadvantages of each previously mentioned. Additionally, and most importantly, there has been a long felt need for a polyol which can function as either a primary polyol or co-polyol in urethane and urethane prepolymer applications and/or compatibilize, i.e. solubilize, reduce viscosity, and make miscible, mixtures of conventional polyester and polyether polyols.

[0016] This invention relates to novel polyester-ether polyols and their use in preparing urethane prepolymers. Additionally, the invention relates to the use of such polyols and prepolymers in making urethane foams and non-foam urethane coatings, adhesives, sealants and/or elastomers. Methods for producing the polyester-ether polyols are disclosed, along with methods for producing urethane prepolymers. It has been surprisingly discovered that the polyester-ether polyols of the instant invention possess highly desirable properties, such as reduced viscosity, improved ease of handling and are highly compatible with ester- and/or ether-based conventional polyols, i.e. they are generally soluble/miscible in either polyester- and/or polyether-based polyols.

[0017] The polyester-ether polyols are useful as either the primary polyols in urethane prepolymers, urethane foams and non-foam urethanes, or as a co-polyol in combination with auxiliary conventional ether- and/or ester-based polyols. Additionally, the polyester-ether polyols generally provide improved hydrolytic stability to CASE materials in which they are utilized.

[0018] It has been surprisingly discovered that the inventive polyester-ether polyols are soluble in and are compatible with other phthalic and/or non-phthalic anhydride based polyester polyols of similar molecular weights, such as caprolactone based polyester polyols, adipic acid based polyester polyols, terephthalate based polyester polyols, isophthalate based polyester polyols, and other aliphatic based polyester polyols. The polyester-ether polyols of the instant invention provide a unique combination of improved low viscosity and compatibility/compatibilization of polyester and polyether based polyols, which allows for the utilization of the conventional ether- and ester-based polyols in combination with each other. The polyester-ether polyols of the instant invention allow for the formation of stable and compatibilized mixtures of ester- and ether-based polyols which are usually immiscible.

[0019] The polyester-ether polyols of the present invention are generally the reaction product of phthalic anhydride (PA), a polyhydroxyl compound, and an alkoxylating agent, e.g., propylene oxide, as shown below:

[0020] wherein R is branched or linear, saturated or unsaturated C_2-10alkyl, cycloalkyl, alkenyl, alkynl, aromatic, polyoxyethylenic, polyoxypropylenic; wherein R may contain pendant secondary functionality such as hydroxyl, aldehyde, ketone, ether, ester, amide, nitrile, amine, nitro, thiol, sulfonate, sulfate, and/or carboxylic groups; n is typically 1-200 and each n1 is independently 1-200. Where pendant secondary hydroxyl functionality is present, such hydroxyl groups may optionally be alkoxylated. Preferably, phthalic anhydride is reacted with a polyol, i.e., a diol such as diethylene glycol to form an intermediate polyester polyol. This intermediate polyester polyol is then reacted with an alkoxylating agent, such as propylene oxide, to form the polyester-ether polyol.

[0021] While a wide variety of polyhydridic alcohols may be utilized in the present invention to prepare the intermediate polyester polyols, preferred PA polyester polyol intermediates are of the form

[0022] wherein n=2-10, x=1-500. Highly preferred PA polyester polyol intermediates for use in the present invention are derived from the condensation of phthalic anhydride and ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, polyethylene glycol, polypropylene glycol triethylene glycol, and tetramethylene glycol and mixtures thereof.

[0023] Alkoxylating agents useful herein include any agent capable of providing a sufficient amount of ether moieties to the final polyester-ether polyol. Preferred alkoxylating agents are ethylene oxide, propylene oxide, butylene oxide, or mixtures thereof.

[0024] The phthalic anhydride based polyester-ether polyols are compatible with standard foam flowing and formation techniques and are also compatible with atmospheric curing, heat curing, and exhibit normal pigmentation compatibility.

[0025] The invention encompasses polyester-ether polyols, methods for preparing such polyols, and their use in preparing urethane prepolymers, urethane foams and non-foam urethane coatings, adhesives, sealants and/or elastomers. The polyester-ether polyols of the instant invention are preferably the reaction product of phthalic anhydride or phthalic acid, a diol, and an alkoxylating agent, wherein the phthalic anhydride or phthalic acid and the diol are first reacted to from an intermediate polyester polyol, which is subsequently reacted with an alkoxylating agent (e.g., propylene oxide), to give a polyester-ether polyol. Although the polyester-ether polyols of the instant invention are useful as the primary polyols in the preparation of urethane prepolymers, urethane foams and CASE materials, they are primarily and preferably useful as compatibilizing polyols in combination with polyester and/or polyether polyols.

[0026] Accordingly, the instant invention encompasses a composition suitable for preparing urethane prepolymers and/or urethane foams or non-foam urethane coatings, adhesives, sealants and/or elastomers, comprising:

[0027] (a) from about 0% to about 5.0% based on the weight of the composition of a urethane catalyst;

[0028] (b) from about 10% to about 90% based on the weight of the composition of a phthalate polyester-ether polyol which is the reaction product of:

[0029] (1) about 2-60% based on the weight of the polyester-ether polyol of phthalic anhydride or phthalic acid; and

[0030] (2) about 40-98% based on the weight of the polyester-ether polyol of at least one polyol of the formula:

[0031] HO—R₁—OH

[0032] wherein R₁represents:

[0033] (a) alkylene groups of about 2 to 10 carbon atoms;

[0034] (b) —CH₂—R₂—CH₂—

[0035] where R₂represents:

[0036] or

[0037] (c) —(R₃O)_n2—R₃—

[0038] where each R₃independently is an alkylene group of about 2 to about 4 carbon atoms, and n2 is an integer of from about 1-200; and

[0039] (3) about 10-80% based on the weight of the polyester-ether polyol of an alkoxylating agent;

[0040] (c) from about 0-50 percent by weight of an auxiliary polyether polyol, polyester polyol, or a mixture thereof;

[0041] (d) from about 0% to about 10% based on the weight of the composition of a blowing agent; and

[0042] (e) from about 0% to about 5% based on the weight of the composition of a compatibilizing surfactant.

[0043] The R₁alkylene groups may be branched or straight chain, saturated or unsaturated, and when R₂contains a hydroxyl moiety, such hydroxyl group may be optionally alkoxylated. The polyester-ether polyol is preferably the reaction product of phthalic anhydride or phthalic acid, the polyol, and the alkoxylating agent, wherein the phthalic anhydride or phthalic acid and the polyol are first reacted to from an intermediate polyester polyol, which is subsequently reacted with the alkoxylating agent to give the polyester-ether polyol.

[0044] The instant invention further encompasses a composition suitable for preparing urethane prepolymers and/or urethane foams or non-foam urethane coatings, adhesives, sealants and/or elastomers, comprising:

[0045] (a) from about 10% to about 60% based on the weight of the composition of an isocyanate;

[0046] (b) from about 50% to about 90% based on the weight of the composition of a phthalate polyester-ether polyol which is the reaction product of:

[0047] (1) about 2-60% based on the weight of the polyester-ether polyol of phthalic anhydride or phthalic acid; and

[0048] (2) about 40-98% based on the weight of the polyester-ether polyol of at least one polyol of the formula:

[0049] HO—R₁—OH

[0050] wherein R₁represents:

[0051] (a) alkylene groups of about 2 to 10 carbon atoms;

[0052] (b) —CH₂—R₂—CH₂—

[0053] where R₂represents:

[0054] or

[0055] (c) —(R₃O)_n2—R₃—

[0056] where each R₃independently is an alkylene group of about 2 to about 4 carbon atoms, and n2 is an integer of from about 1-200; and

[0057] (3) about 10-80% based on the weight of the polyester-ether polyol of an alkoxylating agent.

[0058] (c) from about 0-50% based on the weight of the composition of an auxiliary polyether polyol, polyester polyol, or a mixture thereof;

[0059] (d) from about 0% to about 10% based on the weight of the composition of a blowing agent; and

[0060] (e) from about 0% to about 5% based on the weight of the composition of a compatibilizing surfactant.

[0061] The R alkylene groups may be branched or straight chain, saturated or unsaturated, and when R₂contains a hydroxyl moiety, such hydroxyl group may be optionally alkoxylated. The polyester-ether polyol is preferably the reaction product of phthalic anhydride or phthalic acid, the polyol, and the alkoxylating agent, wherein the phthalic anhydride or phthalic acid and the polyol are first reacted to from an intermediate polyester polyol, which is subsequently reacted with the alkoxylating agent to give the polyester-ether polyol.

[0062] Most commonly when a urethane prepolymer is desired, it is prepared by condensation polymerization, i.e., the isocyanate with the polyol(s), most preferably the polymerization of a diisocyanate with a diol. A prepolymer is generally defined as a non-stoichiometric reaction product of an isocyanate and a polyol. The urethane prepolymers may also be prepared by polymerizing the compositions disclosed herein in the presence of an optional polyamino or a polymercapto-containing compound such as diamino polypropylene glycol or diamino polyethylene glycol or polythioethers such as the condensation products of thiodiglycol either alone or in combination with other glycols such as ethylene glycol, 1,2-propylene glycol or with other polyhydroxy compounds disclosed herein. Also, small amounts of low molecular weight dihydroxy, diamino, or amino hydroxy compounds may be used such as saturated and unsaturated glycols e.g. ethylene glycol or condensates thereof such as diethylene glycol, triethylene glycol, and the like; ethylene diamine, hexamethylene diamine and the like; ethanolamine, propanolamine, N-methyldiethanolamine and the like. Typically for the preparation of urethane prepolymers, the isocyanate, polyol(s), and other components are combined in proportions so as to yield a urethane prepolymer characterized by an isocyanate content of from about 0.25 to about 25%, preferably to about 1 to 10%, and most preferably from 1.5 to 5%. In addition, the ratio of isocyanate equivalents to hydroxyl, amino or mercapto equivalents (known as the isocyanate index) should be greater than 1 but no more than about 2 for prepolymer preparation. The precise amount of the isocyanate used in the polymerization will depend on the equivalent weight and amount of the non-isocyanate components, and the particular isocyanate employed. In general, the amount of the isocyanate needed to achieve the isocyanate content will vary from about 5 to about 55% of the final prepolymer.

[0063] The invention further encompasses a composition suitable for preparing urethane prepolymers and/or urethane foams or non-foam urethane coatings, adhesives, sealants and/or elastomers, comprising:

[0064] (a) from about 10% to about 70% based on the weight of the composition of an isocyanate;

[0065] (b) from about 0.02% to about 5.0% based on the weight of the composition of a urethane catalyst; and

[0066] (c) from about 50% to about 90% based on the weight of the composition of a phthalate polyester-ether polyol which is the reaction product of:

[0067] (1) about 2-60% based on the weight of the polyester-ether polyol of phthalic anhydride or phthalic acid; and

[0068] (2) about 40-98% based on the weight of the polyester-ether polyol of at least one polyol of the formula:

[0069] HO—R₁—OH

[0070] wherein R₁represents:

[0071] (a) alkylene groups of about 2 to 10 carbon atoms;

[0072] (b) —CH₂—R₂—CH₂—

[0073] where R₂represents:

[0074] or

[0075] (c) —(R₃O)_n2—R₃—

[0076] where each R₃independently is an alkylene group of about 2 to about 4 carbon atoms, and n2 is an integer of from about 1-200; and

[0077] (3) about 10-80% based on the weight of the polyester-ether polyol of an alkoxylating agent selected from the group consisting essentially of ethylene oxide, propylene oxide or butylene oxide or mixtures thereof;

[0078] (d) from about 0-50% based on the weight of the composition of an auxiliary polyether polyol, polyester polyol, or a mixture thereof.

[0079] (e) from about 0% to about 10% based on the weight of the composition of a blowing agent; and

[0080] (f) from about 0% to about 5% based on the weight of the composition of a compatibilizing surfactant.

[0081] The R₁alkylene groups may be branched or straight chain, saturated or unsaturated, and when R₂contains a hydroxyl moiety, such hydroxyl group may be optionally alkoxylated. The polyester-ether polyol is preferably the reaction product of phthalic anhydride or phthalic acid, the polyol, and the alkoxylating agent, wherein the phthalic anhydride or phthalic acid and the polyol are first reacted to from an intermediate polyester polyol, which is subsequently reacted with the alkoxylating agent to give the polyester-ether polyol.

[0082] In a more preferred embodiment the compositions suitable for preparing urethane prepolymer and/or urethane foams and non-foam urethane coatings, adhesives, sealants and/or elastomers will comprise from about 10-40%, most preferably from about 10-30% of the isocyanate when present; from about 0.5-4.0%, most preferably from about 0.5-3.0% of the urethane catalyst when present; from about 50-80%, most preferably from about 50-70% of the phthalate polyester-ether polyol, wherein the phthalate polyester-ether polyol preferably comprises from about 10-60%, most preferably 20-50% of phthalic acid or phthalic anhydride; preferably from about 40-80% of the polyol; and preferably from about 10-50% of the alkoxylating agent. In highly preferred embodiments, the alkoxylating agent is propylene oxide and is present in about 50-60% by weight, based on the intermediate polyester polyol. In a more preferred embodiment the urethane prepolymers and/or urethane compositions will comprise from about from about 5-40%, most preferably from about 10-30% of the auxiliary polyether polyol, polyester polyol, or a mixture thereof.

[0083] The compositions disclosed herein may be substantially free of CFC and/or hydrocarbon blowing agents (i.e. they contain less than 1% by weight of a blowing agent) and are suited for use in non-foam applications, i.e., CASE. Alternatively, the compositions of the present invention may optionally contain CFC and/or hydrocarbon blowing agents and be suited for use in foam applications, i.e., open and closed cell foams. Optionally, the composition disclosed herein may additionally contain from about 0.01-20.0% by weight of a polyisocyanurate.

[0084] In a preferred embodiment, the alkoxylating agent is propylene oxide. Highly preferred isocyanates are 2,4- and/or 2,4/2,6-toluene diisocyanate, diphenyl methane 4,4′-diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, or mixtures thereof. Highly preferred urethane catalysts are tetramethylbutanediamine (TMBDA), 1,4-diaza(2,2,2)bicyclooctane (DABCO), dibutyltindilaurate (DBTDL) tinoctoate (SnOct), dimorpholine diethylether (DMDEE), or mixtures thereof.

[0085] A preferred polyester-ether polyol for use in the above and below described compositions has the formula:

[0086] wherein R represents:

[0087] (a) alkylene groups of about 2 to 10 carbon atoms;

[0088] (b) —CH₂—R₂—CH₂—

[0089] where R₂represents:

[0090] (c) —(R₃O)_n2—R₃—

[0091] where each R₃independently is an alkylene group of about 2 to about 4 carbon atoms, and n2 is an integer of from about 1-200; and

[0092] wherein R′ and R″ are independently —[CH₂CH₂O]_n1—, —[CH₂CH(CH₃)O]_n1—, —[CH₂CH₂CH(CH₃)O]_n1—, or a random combination thereof, where n1 is independently 1-200 for R′ and R″; and wherein n is 1-200.

[0093] The R alkylene groups may be branched or straight chain, saturated or unsaturated, and when R₂contains a hydroxyl moiety, such hydroxyl group may be optionally alkoxylated.

[0094] A highly preferred polyester-ether polyol has the formula

[0095] wherein R represents:

[0096] (a) alkylene groups of about 2 to 10 carbon atoms;

[0097] (b) —CH₂—R₂—CH₂—

[0098] where R₂represents:

[0099] (c) —(R₃O)_n2—R₃—

[0100] where each R₃independently is an alkylene group of about 2 to about 4 carbon atoms, and n2 is an integer of from about 1-200; and

[0101] where n1 is independently 1-200; and wherein n is 1-200.

[0102] The R alkylene groups may be branched or straight chain, saturated or unsaturated, and when R₂contains a hydroxyl moiety, such hydroxyl group may be optionally alkoxylated.

[0103] A most preferred polyester-ether polyol has the formula

[0104] wherein each R is —(CH₂CH₂OCH₂CH₂)—; wherein each n1 is independently 1-200; and wherein n=1-200.

[0105] Specific auxiliary polyester polyols suitable for use in the compositions of the invention include for example phthalic acid diethylene glycol polyester polyols. Suitable auxiliary phthalic acid diethylene glycol polyester polyols are commercially available from Stepan Company, Northfield, Ill. Representative auxiliary polyols are StepanPol® PS-2002 (a phthalic anhydride diethylene glycol polyester polyol having an OHv of 195 and a functionality of 2), StepanPol® PS-3152 (a phthalic anhydride diethylene glycol polyester polyol having an OHv of 315 and a functionality of 2), and StepanPol® PS-4002 (a phthalic anhydride diethylene glycol polyester polyol having an OHv of 400 and a functionality of 2), and mixtures thereof. In the instant invention, by OH value (OHv) is meant hydroxyl value, a quantitative measure of the concentration of hydroxyl groups, usually stated as mg KOH/g, i.e., the number of milligrams of potassium hydroxide equivalent to the hydroxyl groups in 1 g of substance. By functionality is meant the number of reactive groups, e.g., hydroxyl groups, in a chemical molecule.

[0106] Other auxiliary polyester polyols, i.e. non-phthalic anhydride-based polyester polyols, include for example, polyester polyols derived from the condensation of caprolactone and a poly alcohol. Specific auxiliary polyether polyols suitable for use in the methods and compositions of the invention include for example the condensation products of propylene glycol/propylene oxide, trimethylolpropane/ethylene oxide/propylene oxide, trimethylolpropane/propylene oxide, sucrose/propylene glycol/propylene oxide, alkylamine/propylene oxide, and glycerin/propylene oxide, and mixtures thereof.

[0107] Although not critical to the present invention, the compositions of the present invention may optionally contain from about 0.01-50.0 percent by weight of a cross linking agent. Suitable cross linking agents are, for example, higher functionality alcohols such as triols or pentaerythitol.

[0108] A wide variety of urethane catalysts are suitable for use in the present invention. Generally, any urethane catalyst capable of effecting a polymerization to form a urethane CASE may be used in the present invention. Examples of suitable urethane catalysts include, among others, tetramethylbutanediamine (TMBDA), 1,4-diaza(2,2,2)bicyclooctane (DABCO), dibutyltindilaurate (DBTDL) and tinoctoate (SnOct), and mixtures thereof.

[0109] Isocyanates useful in the present invention, include among others for example, polyisocyanates, aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates, such as those described, for example, by W. Siefken in Justus Liebigs Annalen der Chemie 562: 75-136. Examples include ethylene diisocyanate; tetramethylene-1,4-diisocyanate, hexamethylene-1,6-diisocyanate; dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-1,3- and 1,4-diisocyanate and mixtures of these isomers; 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (German Auslegeschrift No. 1, 202,785, U.S. Pat. No. 3,401,190); hexahydrotolylene-2,4- and 2,6-diisocyanate and mixtures of these isomers; hexahydrophenylene-1,3- and/or -1,4-diisocyanate; perhydrodiphenylmethane-2,4′- and/or 4,4′-diisocyanate; phenylene-1,3- and -1,4-diisocyanate; tolulene-2,4- and -2,6-diisocyanate and mixtures of these isomers; diphenylmethane-2,4′- and/or -4,4′-diisocyanate; naphthylene-1,5-diisocyanate; triphenyl methane-4,4′,4″-triisocyanate; polyphenyl-polymethylene polyisocyanate which may be obtained by aniline/formaldehyde condensation followed by phosgenation and which have been described, for example, in British Pat. Nos. 874,430 and 848,671; m-and p-isocyanatophenyl sulphonyl isocyanate according to U.S. Pat. No. 3,454,606; perchlorinated aryl polyisocyanate as described, for example, in U.S. Pat. No. 3,277,138; polyisocyanate; containing carbodiimide groups as described in U.S. Pat. No. 3,152,162; the diisocyanates described in U.S. Pat. No. 3,492,330; polyisocyanates containing allophanate groups as described, for example, in British Pat. No. 994,890, Belgian Pat. No. 761, 626 and Published Dutch Patent application No. 7,102, 524; polyisocyanates containing isocyanurate groups as described, for example, in U.S. Pat. No. 3,001,973, in German Pat. Nos. 1,022,789; 1,222,067 and 1,027,394 and in German Offenlegungsschriften Nos. 1,929,034 and 2,004,048; polyisocyanates containing urethane groups as described, for example, in Belgian Pat. No. 752,261 or in U.S. Pat. No. 3,394,164; polyisocyanates containing acrylated urea groups according to German Pat. No. 1,230,778; polyisocyanates containing biuret groups as described, for example, in U.S. Pat. Nos. 3,124,605 and 3,201,372; and in British Pat. No. 889,050; polyisocyanates prepared by telomerization reactions as described, for example in U.S. Pat. No. 3,654,016; polyisocyanates containing ester groups as mentioned, for example, in British Pat. Nos. 965,474 and 1,072,956, in U.S. Pat. No. 3,567,763 and in German Pat. No. 1,231,688; reaction products of the above-mentioned isocyanates with acetals according to German Pat. No. 1,072,385; and, polyisocyanates containing polymeric fatty acid groups as described in U.S. Pat. No. 3,455,883, and mixtures thereof.

[0110] The distillation residues obtained from the commercial production of isocyanates and which still contain isocyanate groups may also be used, optionally dissolved in one or more of the above-mentioned polyisocyanates.

[0111] Other suitable polyisocyanates which are readily available include, for example, toluene-2,4- and -2,6-diisocyanate and mixtures of these isomers (“TDI”); polyphenyl polymethylene polyisocyanates which may be obtained by aniline/formaldehyde condensation followed by phosgenation (“crude MDI”); and, polyisocyanates containing carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret groups (“modified polyisocyanates”), and mixtures thereof.

[0112] Somewhat more preferred polyisocyanates are 2,4- and/or 2,4/2,6-toluene diisocyanate, diphenyl methane 4,4′-diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, and mixtures thereof.

[0113] Suitable polyisocyanurates useful in the present invention also include, as is well known to those skilled in the art, the cyclotrimerization product of any of the aforementioned polyisocyanates.

[0114] Compositions of the present invention may contain optional ingredients, including for example, rheology modifiers, plasticizers, pigments, and waxes.

[0115] Another embodiment of the present invention includes a novel polyester-ether polyol for use in preparing urethane prepolymers, urethane foams and non-urethane coatings, sealants, adhesives and/or elastomers of the formula:

[0116] wherein R represents:

[0117] (a) alkylene groups of about 2 to 10 carbon atoms;

[0118] (b) —CH₂—R₂—CH₂—

[0119] where R₂represents:

[0120] or

[0121] (c) —(R₃O)_n2—R₃—

[0122] where each R₃independently is an alkylene group of about 2 to about 4 carbon atoms, and n2 is an integer of from about 1-200; and

[0123] where n1 is independently 1-200; and

[0124] wherein n is 1-200.

[0125] The R alkylene groups may be branched or straight chain, saturated or unsaturated, and when R₂contains a hydroxyl moiety, such hydroxyl group may be optionally alkoxylated.

[0126] Another embodiment of the present invention includes a novel polyester-ether polyol for use in preparing urethane prepolymers, urethane foams and non-urethane coatings, sealants, adhesives and/or elastomers of the formula:

[0127] wherein each R is —(CH₂CH₂OCH₂CH₂)—; wherein each n1 is independently 1-200; and wherein n=1-200.

[0128] The instant invention further includes methods for preparing a phthalate polyester-ether polyol comprising combining:

[0129] a) about 2-60% based on the weight of phthalate polyester-ether polyol of phthalic anhydride or phthalic acid; and

[0130] b) about 40-98% based on the weight of phthalate polyester-ether polyol of at least one polyol of the formula:

[0131] HO—R₁—OH

[0132] wherein R₁represents:

[0133] (a) alkylene groups of about 2 to 10 carbon atoms;

[0134] (b) —CH₂—R₂—CH₂—

[0135] where R₂represents:

[0136] (c) —(R₃O)_n2—R₃—

[0137] where each R₃independently is an alkylene group of about 2 to about 4 carbon atoms, and n2 is an integer of from about 1-200, to form an intermediate polyester-polyol; and alkoxylating said intermediate polyester polyol with about 10-80% based on the weight of the phthalate polyester-ether polyol of an alkoxylating agent to form the polyester-ether polyol. The R₁alkylene groups may be branched or straight chain, saturated or unsaturated, and when R₂contains a hydroxyl moiety, such hydroxyl group may be optionally alkoxylated.

[0138] The instant invention further includes methods for preparing urethane prepolymers, urethane foams and non-foam urethane coatings, adhesives, sealants and/or elastomers, comprising combining:

[0139] (a) from about 10% to about 60% based on the weight of the composition of an isocyanate;

[0140] (b) from about 0.02% to about 5.0% based on the weight of the composition of a urethane catalyst; and

[0141] (c) from about 50% to about 90% based on the weight of the composition of a phthalate polyester-ether polyol which is the reaction product of:

[0142] (1) about 2-60% based on the weight of phthalate polyester-ether polyol of phthalic anhydride or phthalic acid; and

[0143] (2) about 40-98% based on the weight of phthalate polyester-ether polyol of at least one polyol of the formula:

[0144] HO—R₁—OH

[0145] wherein R₁represents:

[0146] (a) alkylene groups of about 2 to 10 carbon atoms;

[0147] (b) —CH₂—R₂—CH₂—

[0148] where R₂represents:

[0149] (c) —(R₃O)_n2—R₃—

[0150] where each R₃independently is an alkylene group of about 2 to about 4 carbon atoms, and n2 is an integer of from about 1-200; and

[0151] (3) about 10-80% based on the weight of phthalate polyester-ether polyol of an alkoxylating agent; and

[0152] (d) from about 0-50% based on the weight of the composition of an auxiliary polyether polyol, polyester polyol, or a mixture thereof;

[0153] (e) from about 0% to about 10% based on the weight of the composition of a blowing agent;

[0154] (f) from about 0% to about 5% based on the weight of the composition of a compatibilizing surfactant, to form a mixture; and

[0155] reacting/polymerizing the mixture to form a urethane prepolymer, urethane foam or non-foam urethane coating, adhesive, sealant and/or elastomer. The polyester-ether polyol is preferably the reaction product of phthalic anhydride or phthalic acid, the polyol, and the alkoxylating agent, wherein the phthalic anhydride or phthalic acid and the polyol are first reacted to from an intermediate polyester polyol, which is subsequently reacted with the alkoxylating agent to give the polyester-ether polyol.

[0156] Another embodiment of the present invention includes urethane prepolymers, urethane foams and non-foam urethanes suitable for use in a coatings, adhesives, sealants and/or elastomers which are made from polymerizing the compositions suitable for preparing such materials as described herein.

[0157] The merits of this invention are further supported by the following non-limiting and illustrative examples.

[0158] As used in the Examples and description appearing below, the following designations, symbols, terms and abbreviations have the indicated meanings:

[0159] In the following examples, all amounts are stated in percent by weight of active material unless indicated otherwise. One skilled in the art will recognize that modifications may be made in the present invention without deviating from the spirit or scope of the invention. The invention is illustrated by the examples contained within; such examples are not to be construed as limiting the invention or scope of the specific procedures or compositions described herein.

[0160] The following raw materials in Table I were used without purification in the examples which follow (abbreviations used are PA=phthalic anhydride, DEG=diethylene glycol, PPG=polypropylene glycol, PPO=polypropylene oxide, Gyl=glycerin, Su=sucrose, OHv=hydroxyl value in mg KOH/g). Polyols A and B are commercially available polyester polyols used as comparative examples as indicated below.

[0161] As shown in Table II, polyol C (comparative example) is a standard PA-DEG polyol (StepanPol PS-2002) and polyols D and E are examples of polyester-ether polyols. Both these polyols were prepared by the propoxylation of a ortho-phthalate diethylene glycol ester (StepanPol PS-2002).

[0162] PS-2002 is prepared as the condensation product of about 45% diethylene glycol (DEG) and 55% phthalic anhydride. Into a three gallon kettle is charged 4500 g of DEG and 5500 g PA. This mixture is heated to about 180° C. for four hours under a nitrogen atmosphere. After four hours the temperature is raised to about 180-200° C., and approximately 500 ppm of catalyst tetrabutyl titinate (Tyzor TBT, DuPont) is added to the kettle. The pressure is reduced in the kettle and removal the water by-product is begun under vacuum. The water is completely removed after about 24 hours of reaction at about 180-200° C. under vacuum. The final polyester polyol is characterized by a hydroxyl number of 190-200 mg KOH/g and has a Brookfield viscosity of about 20,000-30,000 cPs at 25° C. and an acid value less than 1 mg KOH/g.

[0163] Into a two gallon steel pressure Chemineer kettle is charged 3678 grams StepanPol® PS-2002 and 155 grams of crushed potassium hydroxide. The mixture is blended under a nitrogen blanket for 2 hours at 120° C. A total of 7,060 grams of propylene oxide is added under a pressure of <42 psig over three hours at a temperature of about 120-125° C. A total of 500 grams of this crude product is then transferred to a flask where it is then heated to about 100° C. and degassed to remove unreacted propylene oxide. The material is then finished/neutralized: To the remaining warm mixture, 1.5 grams of Magnesol HMR-LS (The Dallas Group) is added and the mixture is then stirred at about 100-120° C. for four hours. The resulting mixture is allowed to stand warm (80° C.) for approximately 12 hours and the product is decanted and filtered through a vacuum flask equipped with a Buchner funnel and a #4 Whatman filter paper. Approximately 0.1% H₃PO₄(85%) by weight of the polyol is then added. Analysis of polyol D gave the following properties:

[0164] Polyol E is prepared in a similar manner to that of polyol D, except the amounts of materials used are 14.5 g KOH, 2890 g, StepanPol PS-2002 and 6010 g propylene oxide. Analysis of polyol E gave the following properties:

[0165] Polyol F was prepared in a similar manner to than of Polyol E, but with a 128 mg KOH/g PA-DEG polyol as an initiator (438 g/eq); the initiator used is 2,965 grams of a 128 Ohv PA-DEG polyol, along with 20.1 g of 45% KOH (aqueous) and 2,360 grams of propylene oxide to give a propoxylated polyester ether polyol with an OH value of 82 mg KOH/g and subsequently finished/neutralized as described in Example 2 above. Analysis of polyol E gave the following properties:

[0166] Polyol G is prepared in a manner similar to Polyol F (2,965 grams of a 128 Ohv PA-DEG initiator, 20.1 grams of 45% KOH), but propoxylated (6,360 grams of propylene oxide) to an OH value of 53.8 mg KOH/g and subsequently finished/neutralized. Analysis of polyol E gave the following properties:

[0167] Prepolymers are generally prepared by the reaction of a polyol with an isocyanate at about 60-70° C. over a two hour period in a reactor equipped with agitation means and a slow nitrogen pad. The polyol is first warmed to 80° C. followed by the addition of the required amount of isocyanate flakes to form a mixture. The mixture is then sealed and allowed to cool over a 12 hour period to about 25° C.; the weight percent of unreacted isocyanate (% NCO) is then determined in accordance with test ASTM D 2582-80.

[0168] Dynamic viscosity is determined with a Brookfield RVT viscometer equipped with a #31 spindle, Thermocel and temperature controller. Table III gives the prepolymer nomenclature, formulations and results.

[0169] Elastomer Preparation

[0170] Elastomers are prepared by hand mixing the appropriate amount of prepolymer (H-J) with 1,4-butane diol for approximately 15 seconds, followed by the addition of one drop of DBTDL catalyst and approximately 10 seconds of additional hand mixing and casting into metal molds which are preheated to about 120° C. Elastomer parts were cured by placing the mold in a 120° C. oven for one hour, followed by removal and allowing the mold and contents to cool about 25° C. for at least four hours before extracting parts. Table IV gives formulation data for the elastomer samples (L-N).

[0171] Adhesion Sample Preparation

[0172] Adhesion samples were prepared by moistening 1″×2″ stainless steel strips (Q-Panel Lab Products) with a small amount of prepolymer (Table II) and then pressing a wood tongue depressor, by means of a five pound weight, onto the steel strip for 12 hours to form a bonded sample. The bonded samples were then evaluated using a “Pull apart test” approximately 24 hours later to classify the method of failure, as detailed more fully as described below. The “Pull apart test” entails bonding two surfaces together with a particular material, allowing the bond to dry/cure at room temperature (i.e., 25° C.) for approximately 24 hours, grasping both surfaces (one in each hand) and pulling the surfaces apart, followed by visual qualitative observation of the previously bonded surfaces to look for torn substrate fragments (substrate failure), torn adhesive (cohesive failure) or one clean surface (adhesive failure).

[0173] Elastomer Sample Evaluation

[0174] Elastomers prepared in Table IV were evaluated for Tensile Strength (ASTM D 638-91 method), Elongation (ASTM D 638-91 method) and Shore A and Shore D Hardness (ASTM D-2240-91 method). The results are presented below.

[0175] As can be seen by the above results, the formulation prepared from inventive Polyol D (in Elastomer L) exhibits greater tensile strength and elongation than that of Elastomer M, prepared from the conventional Polyol A, even though both specimens exhibit the same hardness.

[0176] As can be seen by the above results, the corresponding prepolymer of a pure PA-DEG polyester polyol is approximately 25,500 cP @ 25° C., where as the prepolymer of the polyester-ether polyol material is less than 10% of that viscosity, a highly desirable characteristic.

[0177] Adhesion Evaluations

[0178] For the metal-wood bond sample formed with prepolymer H, the failure method was cohesive; i.e., as an attempt was made to separate the wood and metal members by hand, both the wood and metal separated in tact, visibly undamaged and with adhesive residue on both the formerly bonded wood and metal surfaces.

[0179] For the metal-wood bond formed with Prepolymer J, the failure method was substrate; i.e., as an attempt was made to separate the wood and metal by hand, the wood split, leaving fragments of wood bonded to the metal.

[0180] In accordance with these qualitative results, substrate failure is almost always preferred in structural (load-bearing members) bonding, since the adhesive is stronger than one of the substrates. Here, the PPG-prepolymer/adhesive failed undesirably, as compared to the prepolymer made from the novel polyester-ether polyol, i.e. the material gave a more desirable failure.

[0181] Solubility Evaluations

[0182] The following polyol materials shown in Table V were used to explore the solubility, i.e., compatibility, of inventive polyester-ether polyols in other various ester- and ether-based polyols.

[0183] Blends of Polyol E and each of polyols in Table V above are made at weight ratio of 25:50 grams, 50:50 grams and 75:50 grams, respectively, in six ounce, open-mouth, clear flint glass jars. Similar blends are made with Polyol G. In each case (at each weight ratio), all the mixtures were visibly clear (formed soluble systems).

[0184] When Polyol E (or polyol G) are replaced in an identical series of experiments with either Polyols I, J, or N no solubility at any level was observed with any of the polyether polyols (A, B, F, G, H).

[0185] Polyol D will dissolve in either polyether or polyester glycols which is necessary to make stable two-part systems. Essentially, PA-DEG propoxylated to 55-58% propylene oxide by weight will be soluble in either ether or ester glycols. More propylene oxide by weight makes the product soluble on PPGs only; less PO with an ester is soluble only in ester glycols.

[0186] All documents, e.g., patents and journal articles, cited above or below are hereby incorporated by reference in their entirety.

[0187] From the foregoing, it will be appreciated that although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit or scope of the invention.