Low residual monomeric diol aromatic polyester polyols

Abstract

An aromatic polyester polyol comprising: a total product OH number of from 150 to 450; -a viscosity of less than 12,000 cp; -lt; 30% of the OH number of the residual monomeric diol of the total product OH number; -a residual monomeric diol in an amount of less than 10 wt%; and-a level of 1, 4-dioxane of less than 50.

Description

TECHNICAL FIELD

[0001] The present invention relates to low residual monomer glycol aromatic polyester polyols. More particularly, the present invention relates to low residual monomer glycol aromatic polyester polyols produced using a thermal separation process under vacuum. BACKGROUND

[0002] Energy usage has long been a concern for consumers, particularly in the construction of permanent dwellings. However, recent spikes in fuel costs and potential shortages of home heating oil only serve to exacerbate these concerns. One tool that consumers use to mitigate the effects of this is the use of insulating materials, which can be used not only in new construction, but also in renovations. In particular, spray applied insulating foams are increasingly used in such applications due to their excellent insulating properties and ability to block air flow. Such materials not only serve to insulate, but also act as a barrier to air, moisture and vapor, and can be used to seal attics, exterior walls and wall cavities. The increased demand for polyurethane spray foams has spurred foam precursor (such as polyester polyols) suppliers to correspondingly increase their performance and cost effectiveness expectations.

[0003] In polyurethane applications, polyols of high functionality and / or high terephthalate content have viscosities of 12000 cp or less, preferably < 8000 cp, and in some cases < 6000 cp are desirable because these products allow formulators to process aromatic polyester polyols for PUIR / PIR systems with improved mechanical and flame retardant properties. Conventional aromatic polyester polyols can contain up to 25% residual monomer diols depending on the product hydroxyl value; and the presence of residual monomer diols in the polyol results in lower product viscosities. Additionally, formulators often employ high equivalent weight diols, such as triethylene glycol, tetraethylene glycol, PEG 200, PEG 400 and PEG 600 to reduce the viscosity of aromatic polyester polyols with high functionality. In both cases, the presence of high residual monomer diols and the use of high equivalent weight molecular weight diols results in a reduction of aromatic structure in the polyol, which further results in poor mechanical and poor burn performance of the subsequent foam.

[0004] For these reasons, there has been an ongoing effort to improve the performance of polyols; for example, U.S. 9,809,674, CN104262596, CN110563935, CN103724598 are directed to high functionality aromatic polyester polyols; U.S. 8,912,364, U.S. 5,689,012, U.S. 6,713,599, and U.S. 8,680,211 are directed to a narrow range of molecular weight polyols; WO2010 / 051962, WO2010 / 142399, and U.S. 8,481,606 are directed to low 1,4-dioxane polyester polyols. Nonetheless, there is a continuing need for polyol compositions that provide improved performance, especially in spray foam applications. SUMMARY

[0005] In conventional polyols, the presence of residual monomer diol at a level of 10% provides a lower viscosity. Residual monomer diol significantly increases the overall hydroxyl value of the product, and often > 35% of the product OH value of conventional aromatic polyester polyols comes from the OH of the residual monomer diol. Removing residual diol in the final product to a level of < 10%, and in some cases to a level of < 5%, reduces the OH value, however, this inevitably increases the product viscosity. Applicants have discovered low viscosity aromatic polyester polyol compositions with lower residual monomer diol. Such polyol compositions have higher polymer content and higher aromaticity, providing better mechanical properties and higher flame retardancy to PU / PIR foams. Reducing residual monomer diol also reduces the overall OH value of the polyester polyol product. In PU / PIR applications, low OH products facilitate optimization of MDI usage.

[0006] Polyols containing high functionality, high terephthalic acid (TA), and viscosity below 10,000 cp are also desirable in polyurethane applications, as these products have good mechanical properties and burning properties in PU and PIR systems. Conventional prepared polyesters typically have a viscosity above 10,000 cp (especially for functionality higher than 2), thus a viscosity modifier or excess diol is needed to control the viscosity.

[0007] In one embodiment, the present invention is directed to an aromatic polyester polyol comprising a total product OH value of 150 to 450; a viscosity of less than 12,000 cp; residual monomer diol in an amount of less than 10 wt%; a total OH of residual monomer diol of < 30% of the total product OH value; and a level of 1,4-dioxane of less than 50 ppm.

[0008] In another embodiment, the present invention is directed to a method for making a low viscosity aromatic polyester polyol product. In another embodiment, the present invention is directed to a method comprising: feeding a feed stream comprising a diol stream, an aromatic stream comprising at least one of an aromatic ester and an acid, and a catalyst stream to a reactor, wherein the diol stream is selected from monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, higher diols, dipropylene glycol, methylpropanediol, higher molecular weight polyethylene glycols and polypropylene glycols, higher functionality diols such as glycerol, trimethylolpropane, pentaerythritol, glucosides and alkyl substituted glucosides; and the aromatic acid / ester is selected from terephthalic acid, isophthalic acid, phthalic acid / anhydride, trimellitic anhydride and their corresponding esters or combinations thereof; reacting the feed stream in the reactor to form an intermediate product stream comprising water, diol, optionally 1,4-dioxane, and an aromatic polyester polyol having a total product OH value greater than 250. Separating the intermediate product stream by a thermal separation process under vacuum into a diol rich stream and a product stream having a total product OH value less than 450, a viscosity less than 12,000 cp; and a level of residual monomer diol of less than 10 wt%. The intermediate product stream contains more than a 10%-50% excess of residual monomer diol, and preferably about a 20%-35% excess of residual monomer diol. Subsequently, the excess residual monomer diol in the intermediate stream is removed by a thermal separation process under vacuum to produce a diol overhead (ovh) stream comprising primarily monomer diol and a bottoms stream comprising the inventive polyol with low residual monomer diol, as described above.

[0009] In another embodiment, the present invention is directed to an aromatic polyester polyol having a 1,4-dioxane level of < 50 ppm.

[0010] In yet another embodiment, the present invention is directed to a polyurethane foam comprising an aromatic polyester polyol, a surfactant, a catalyst, an isocyanate, and a blowing agent, wherein the aromatic polyester polyol comprises a total OH product value of 150 to 450; a viscosity of less than 12,000 cp; a residual monomer diol of less than 10 wt%; and a level of 1,4-dioxane of less than 50 ppm. Preferably, when the total product OH value is less than or equal to 220, the residual monomer diol is less than 4 wt%; when the total product OH value is less than 280, the residual monomer diol is less than 6 wt%, when the total product OH value is less than 350, the residual monomer diol is less than 8 wt%; and when the total product OH value is less than 450, the residual monomer diol is less than 10 wt%. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 A wiped film evaporator is shown to act as a thermal separation device for removing excess diol in the intermediate polyol product.

[0012] Figure 2 A smoke tester is shown for polyurethane and polyisocyanurate foam comparative smoke testing.

[0013] Figure 3 A green strength comparison of the inventive polyol to commercially produced polyols is shown. DETAILED DESCRIPTION

[0014] The present subject matter relates to low viscosity polyols with reduced residual monomeric diol levels, where the OH value of the residual monomeric diol is less than 30% of the total product hydroxyl groups. As shown in Table 1, typical aromatic polyester polyols on the market contain 7% to 20% residual monomeric diol, depending on the product OH value. While the residual diol in aromatic polyester polyols increases as the product hydroxyl value increases, in all cases, the OH value of the residual diol is always greater than 35% of the total product hydroxyl groups.

[0015] Table 1. Residual monomeric diol in current commercial aromatic polyester polyols.

[0016]

[0017] The polyols of the present subject matter also provide improved fire performance and green strength. For polyester polyols made with diethylene glycol, the polyols of the present subject matter further have a pathway to low to no 1,4-dioxane, a possible carcinogen, lower storage crystallization potential, high PTA polyester, and ultra-high (> 3.0) functionality.

[0018] In one embodiment, the present invention relates to an aromatic polyester polyol comprising a total product OH value of 150 to 450; a viscosity of less than 12,000 cp; an OH of residual monomeric diol of < 30%; residual monomeric diol in an amount of less than 10 wt%; and 1,4-dioxane at a level of less than 50 ppm.

[0019] With respect to the characterization of the aromatic polyester polyols of the present subject matter, the hydroxyl value or OH is reported in mg KOH / g and measured according to the ASTM D6342 standard. The acid value is reported in mg KOH / g and measured according to the ASTM 4662 standard. The water content of the polyol is measured according to the ASTM D4672 standard. The viscosity of the polyol is measured at 25°C using a Brookfield viscometer according to the ASTM D4878 standard.

[0020] For the purposes of this specification, the term "residual monomer diol" includes the sum of all unreacted diols used in the esterification process. The residual monomer diol can be ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, glycerol, and other monomer diols used to make the polyol. The residual monomer diol in the polyol can be measured by gas chromatography with a flame ionization detector using a DB-1 column and a silanization reagent to quantitatively analyze the residual diols. The gas chromatography used for the analysis has been standardized against the relevant diol standards. The development of gas chromatography for the analysis of low molecular weight diols, such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, glycerol, and the like, using a silanization reagent is known in the art and can be readily developed by one of ordinary skill and / or one of ordinary knowledge in the art.

[0021] Preferably, the aromatic polyester polyol has a total product OH value of less than 200 and a viscosity of less than 10,000 cp at 25°C, preferably less than 8000 cp at 25°C. Preferably, the aromatic polyester polyol has a functionality between 2.2 and 3.5, a total product OH value of less than <400 mg KOH / gram of sample, and a product viscosity of less than 12000 cp at 25°C, preferably less than 8000 cp at 25°C.

[0022] Preferably, the aromatic polyester polyol is free of flame retardants and / or other additives that reduce the viscosity and / or the hydroxyl value of the product. For the purposes of this specification, the term "flame retardant" includes solid or liquid compounds containing phosphorous, chlorine, bromine, boron, nitrogen, or combinations of these elements. Examples include brominated phthalate glycols, ammonium polyphosphate, triethyl phosphate, tris(2-chloroisopropyl) phosphate, tetrakis(2-chloroethyl) ethylene diphosphate, tris(beta-chloroethyl) phosphate, tris(2,3-dibromopropyl) phosphate, and the like. The term "additive" includes diluents, such as propylene carbonate, dimethyl basic ester (DBE), non-ionic surfactants, and the like, intended to reduce the viscosity of the polyol.

[0023] Preferably, the aromatic polyester polyol has an average functionality or average hydroxyl functionality greater than 1.9, preferably between 1.95 and 3.5, and a viscosity of less than 12,000 cp. The term "average functionality" or "average hydroxyl functionality" of a polyol indicates the average number of -OH groups per molecule. One way to determine the average functionality is by measuring the average molecular weight (Mn) of the polyol by gel permeation chromatography. The average functionality is:

[0024] Average functionality = polyol equivalent weight (Eqwt) / Mn

[0025] where Eqwt = 56,100 / the number of OH groups of the polyol, and Mn is the average molecular weight of the polyol.

[0026] Preferably, the residual monomer diol is less than 4 wt% when the total product OH value of the aromatic polyester polyol is less than 220.

[0027] Preferably, the residual monomer diol is less than 6 wt% when the total product OH value of the aromatic polyester polyol is less than 280.

[0028] Preferably, the residual monomer diol is less than 8 wt% when the total product OH value of the aromatic polyester polyol is less than 350.

[0029] Preferably, the residual monomer diol is less than 10 wt% when the total product OH value of the aromatic polyester polyol is less than 450.

[0030] In another embodiment, the present application is directed to a method comprising: feeding a feed stream comprising a diol stream, an aromatic stream comprising at least one of an aromatic ester and an acid, and a catalyst stream to a reactor, wherein the diol stream is selected from monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, higher glycols, dipropylene glycol, methylpropanediol, higher molecular weight polyethylene glycols and polypropylene glycols, higher functionality diols such as glycerol, trimethylolpropane, pentaerythritol, glucosides and alkyl substituted glucosides; and the aromatic acid / ester is selected from terephthalic acid, isophthalic acid, phthalic acid / anhydride, trimellitic anhydride and their corresponding esters or combinations thereof; reacting the feed stream in the reactor, thereby forming an intermediate product stream. The intermediate product stream contains 10%-50% residual monomer diol, and preferably about 20%-35% residual monomer diol. Subsequently, the residual monomer diol in the intermediate product stream is separated by a thermal separation process under vacuum into a diol rich stream and a product stream that is an aromatic polyester polyol of the present application having a total product OH value of less than 450, a viscosity of less than 12000 cp; and a level of residual monomer diol of less than 10 wt%.

[0031] Preferably, in the method, the feed stream further comprises a hydroxyl terminated material in the diol stream, and the acid stream further comprises at least one of a fatty acid family / ester, a fatty acid / oil or combinations thereof. The fatty acid in the acid stream can contain succinic acid, glutaric acid, adipic acid and / or their esters and / or combinations thereof.

[0032] Preferably, in the method, the hydroxyl terminated material is an alkanolamine selected from diethanolamine, triethanolamine, substituted ethanolamines or mixtures thereof.

[0033] Preferably, in the method, the fatty acid is selected from succinic acid, glutaric acid, adipic acid, their esters or combinations thereof.

[0034] Preferably, the ratio of the diol stream to the aromatic stream is from 2.4 to 4.

[0035] Preferably, the reaction is conducted at a reaction temperature of 180°C to 235°C.

[0036] Preferably, the vacuum separation is conducted at a temperature of 130°C to 170°C and a pressure of 0.1 mmHG to 20 mmHG.

[0037] In the reaction to form the intermediate polyol, the diol stream is selected from monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, higher diols, dipropylene glycol, methylpropanediol, higher molecular weight polyethylene glycols and polypropylene glycols, higher functionality diols such as glycerol, trimethylolpropane, pentaerythritol, glucoside, and alkyl substituted glucosides, or combinations thereof.

[0038] The diol stream is preferably selected from monoethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, or mixtures thereof. More preferably, the diol stream is selected from diethylene glycol and polyethylene glycol. To make polyols of functionality higher than 2, triols and higher functionality alcohols can be added including glycerol, trimethylol, pentaerythritol, glucoside, and alkyl substituted glucosides.

[0039] In the reaction to form the intermediate polyol, other hydroxyl terminated materials can also be added or used in the feed stream such as alkanolamines including diethanolamine, triethanolamine, substituted ethanolamines, and the like.

[0040] The process can further comprise at least one of a hydroxyl terminated material, and / or an aliphatic acid / ester, a fatty acid, and a natural oil, or combinations thereof, in the feed stream. The aliphatic acid can contain succinic acid, glutaric acid, adipic acid, and / or esters and / or combinations thereof in the acid stream.

[0041] The aromatic acids / esters in the aromatic stream are preferably selected from terephthalic acid, phthalic anhydride, isophthalic acid, trimellitic anhydride, and / or esters thereof and / or intermediates and / or by-products produced during the production of these acids / esters. More preferably, the aromatic esters are selected from terephthalic acid, phthalic anhydride, and / or esters thereof. In the reaction to form the intermediate polyol, other modifiers, such as aliphatic acids and / or fatty acid / oil derivatives, can be used as hydrophobic reactants for the preparation of the polyol. Preferably, the aliphatic acids / esters are selected from succinic acid, glutaric acid, adipic acid, and / or esters thereof and / or combinations thereof. Fatty acids include, for example, hexanoic acid, octanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid, and the like, and mixtures thereof. Fatty acid esters include, for example, fatty methyl esters such as methyl laurate, methyl palmitate, methyl oleate, and the like. Fatty alcohols include, for example, decanol, oleyl alcohol, dodecanol, tridecanol, and the like. Natural oils include, for example, soybean oil, sunflower oil, castor oil, corn oil, olive oil, palm oil, tall oil, tallow, and the like. Alkyl phenols include, for example, octyl phenol, nonyl phenol, decyl phenol, dodecyl phenol, and the like.

[0042] A catalyst is used in the reaction to form the intermediate polyol. Preferably, the catalyst is selected from, but not limited to, titanates such as tetrabutyl titanate, tetraisopropyl titanate, and metal-based oxides such as dibutyl tin oxide, lead oxide, antimony oxide, and combinations thereof. Other catalysts can also be used, including alkali metal catalysts or Lewis acids or Brønsted acids.

[0043] The reaction to form the intermediate polyol is an esterification and / or transesterification reaction that is carried out at a temperature between 180 °C and 250 °C, preferably between 210 °C and 230 °C. The reaction is carried out in the presence of the catalyst described above, typically in the range of 10 ppm to 2000 ppm, more preferably between 200 ppm and 600 ppm.

[0044] The reactor in which the reaction to prepare the intermediate polyol is carried out is a closed vessel that is configured and selected to safely accommodate the continuous agitation and nitrogen purging of the reactants and / or reaction mixture, minimize the loss of reactants, and quantitatively obtain the by-products produced during the reaction, such as water. The reaction vessel is equipped with mechanical agitation, nitrogen inlet, packed column, condenser with receiver, and temperature control for monitoring the reactor and column overhead temperatures. The procedure and conditions for the esterification / transesterification reaction are known in the art (see U.S. Patent 3.647,759, the disclosure of which is incorporated herein by reference).

[0045] The intermediate product stream from the esterification / transesterification reaction contains hydroxyl terminated oligomers and high levels of residual monomer diol, with the total product OH value of the intermediate product > 250 mgKOH / gram of sample. If diethylene glycol is used as the monomer, 1,4-dioxane can also be present in the intermediate product stream. Depending on the initial diol to acid ratio used in the reaction, the intermediate polyol can contain up to 50% or more of the residual monomer diol. The intermediate product stream is then thermally separated at temperatures below 200°C, preferably between 140°C and 180°C. The molecular weight (MW) distribution of the low diol product in the bottoms stream can be controlled by varying the diol / acid ratio during the esterification / transesterification process, varying the separation temperature, and / or the ratio of the overhead stream to the bottoms stream of the thermal separation process, and then stripping the excess diol under vacuum at temperatures below 200°C. Preferably, the ratio of the diol stream to the aromatic stream is 2.0 to 4.0.

[0046] Thermal separation process under vacuum

[0047] The thermal separation process under vacuum at temperatures below 200°C is used to remove excess diol from the polyester polyol. This process can also be used to remove unwanted contaminants such as 1,4-dioxane. The thermal separation process can include the use of wiped film evaporators (WFE), molecular stills (MSD), vacuum distillation, and short path molecular distillation equipment. The use of WFE and MSD is preferred. Figure 1 A process is demonstrated for making residual monomer diol polyols using an esterification process where a WFE is used to separate volatile compounds and unreacted diol monomers. In the WFE process, a mechanically agitated thin film of the feed material is introduced to a heated surface under vacuum to effectively remove the residual monomer diol at lower temperatures (below 200°C) and shorter residence times. Both the operating temperature and shorter residence times minimize the total thermal exposure of the product, preventing excessive thermal degradation and minimizing the production of higher molecular weight oligomers, resulting in higher viscosity polyol products. The temperature of the thermal separation process is preferably 130°C to 170°C. The pressure of the thermal separation process is preferably 0.1 mm Hg to 20 mm Hg.

[0048] When using diethylene glycol to produce the intermediate, 1,4-dioxane is produced as a byproduct. 1,4-Dioxane is a hazardous byproduct produced during the esterification process. In a process to remove monomeric diethylene glycol from the intermediate, the 1,4-dioxane produced in the process is also stripped overhead and a polyol with a low 1,4-dioxane content, i.e., the final product, is obtained in the bottoms stream. The resulting polyester polyol has a total product OH value of less than 400, a viscosity of less than 15,000 cp, and a residual monomeric diol level of less than 10 wt%. Preferably, when the total product OH value of the aromatic polyester polyol is less than or equal to 220, the residual monomeric diol is less than 4 wt%; when the total product OH value is less than 280, the residual monomeric diol is less than 6 wt%; when the total product OH value is less than 350, the residual monomeric diol is less than 8 wt%; and when the total product OH value is less than 450, the residual monomeric diol is less than 10 wt%. Preferably, the polyester polyol has a 1,4-dioxane level of < 50 ppm or is not detectable.

[0049] In yet another embodiment, the present invention is directed to a polyurethane and / or polyisocyanurate foam comprising an aromatic polyester polyol, a surfactant, a catalyst, an isocyanate, and a blowing agent, wherein the aromatic polyester polyol comprises a total product OH value of 150 to 450; a viscosity of less than 12,000 cp; a total OH value of residual monomeric diol of < 30%; a residual monomeric diol in an amount of less than 10 wt%; and a level of 1,4-dioxane of less than 50 ppm.

[0050] In another embodiment, the present invention is directed to an aliphatic polyester polyol or a mixed aliphatic / aromatic polyester polyol comprising a total product OH value of < 120; a viscosity of less than 20,000 cp; an OH value of residual monomeric diol of < 5% of the total product OH value; and a residual monomeric diol in an amount of less than 1%.

[0051] Preferably, when the total product OH value of the aliphatic polyester polyol or the mixed aliphatic / aromatic polyester polyol is less than 80, the residual monomeric diol is less than 0.5 wt%. More preferably, the residual monomeric diol is less than 0.2 wt% and the viscosity is < 18,000 cp.

[0052] Preferably, the aliphatic polyester polyol or the mixed aliphatic / aromatic polyester polyol has a functionality of 1.9 to 4.

[0053] The aliphatic polyester polyols or mixed aliphatic / aromatic polyester polyols can be produced by feeding a feed stream comprising a diol stream and an aromatic stream comprising at least one of aromatic aliphatic and / or aromatic esters and acids and a catalyst stream to a reactor, wherein the diol stream is selected from monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, higher diols, dipropylene glycol, methylpropanediol, higher molecular weight polyethylene glycols and polypropylene glycols, higher functionality diols such as glycerol, trimethylolpropane, pentaerythritol, glucosides and alkyl substituted glucosides, the aliphatic acid / ester and / or aromatic acid is selected from succinic acid, glutaric acid, adipic acid, terephthalic acid, isophthalic acid, phthalic acid / anhydride, trimellitic anhydride and other di / multi-acids and their corresponding esters or combinations. The feed stream is reacted in the reactor to form an intermediate stream, wherein the residual monomer diol is in excess of 0.8% and preferably in excess of 1.5%. Finally, the excess residual monomer diol in the intermediate stream is removed by a thermal separation process under vacuum to a top stream as a diol rich stream and a bottom stream as the aliphatic polyester polyol or mixed aliphatic / aromatic polyester polyol of the present invention.

[0054] In yet another embodiment, the present invention relates to a polyurethane flexible foam comprising the aliphatic polyester polyol or mixed aromatic polyester polyol of the present invention, a surfactant, a catalyst, an isocyanate.

[0055] isocyanate

[0056] Suitable isocyanates for use are well known and many are available from Dow Chemical (under the PAPI TM , ISONATE ® , and VORONATE TM brands), Evonik (VESTANAT ® ), BASF (LUPRANATE ® ), Covestro (MONDUR ® and DESMODUR ® ), Huntsman (RUBINATE ®) and other polyurethane intermediate suppliers. Suitable isocyanates have an average NCO functionality (reactive groups per molecule) in the range of 2.0 to 3.0. The isocyanates can be aromatic or aliphatic. Aromatic isocyanates include, for example, toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI) or polymeric diisocyanate (p-MDI), and the like. Aliphatic isocyanates include, for example, hexamethylene diisocyanate (HDI), hydrogenated MDI, cyclohexane diisocyanate (CHDI), isophorone diisocyanate (IPDI), trimethyl or tetramethyl hexamethylene diisocyanate (TMXDI), and the like. Aromatic isocyanates, especially polymeric MDI with an NCO functionality in the range of 2.3 to 3.0 are preferred. Suitable polymeric MDI include, for example, LUPRANATE ® M-10 (average NCO functionality = 2.3) and LUPRANATE ® M-20 (average NCO functionality = 2.7), a product of BASF, and MONDUR ® 489 (modified polymeric MDI, average NCO functionality = 2.9), a product of Covestro. Mixtures of different isocyanates can be used. Dimerized and trimerized isocyanates can be used. In some aspects, aromatic isocyanates, such as p-MDI are preferred.

[0057] blowing agent

[0058] The blowing agent can include aliphatic or cycloaliphatic C4-C6 hydrocarbons, water, mono- and polycarboxylic acids and their salts, tertiary alcohols, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halogenated hydrocarbons, hydrofluoroolefins (HFOs), and the like, and mixtures thereof. For further examples of suitable blowing agents, see U.S. Patent No. 6,359,022, the teachings of which are incorporated herein by reference.

[0059] surfactant

[0060] Surfactants are used in the process of producing rigid PUR or PIR foams to enable the production of closed-cell rigid foams. Representative examples include products available from Evonik, Dow Chemical, Siltech, Momentive Performance Materials, and include, among others, TEGOSTAB ® B silicone surfactant (Evonik), SILSTAB ® silicone surfactant (Siltech), VORASURF TM surfactant (Dow), NIAX ®Surfactants (Momentive) and the like. Other suitable surfactants are polysiloxanes or other silicon-based surfactants.

[0061] Catalyst

[0062] Suitable catalysts for use include compounds that catalyze the reaction of isocyanate with water ("blowing catalysts"), and compounds that catalyze the formation of urethane, urea, or isocyanurate linkages ("PU catalysts," "PIR catalysts," or "trimerization catalysts").

[0063] Amine catalysts are typically tertiary amines or alkanolamines, and mixtures thereof with diluents, typically diols such as dipropylene glycol. Examples include bis(2-dimethylaminoethyl)ether, N,N-dimethylaminopropylamine, N,N-dimethylethanolamine, triethylenediamine, benzyldimethylamine, N,N-dimethylcyclohexylamine, N,N,N',N',N"-pentamethyldiethylenetriamine (PMDETA), diethanolamine, N-ethylmorpholine, N,N,N'N'-tetramethylbutanediamine, 1,4-diazabicyclo[2.2.2]octane, and the like, and combinations thereof. Examples also include POLYCAT ® 5 or POLYCAT ® 8 (Evonik) and NIAX ® A-1 or NIAX ® A-99 (Momentive).

[0064] Other catalysts include carboxylate salts (e.g., potassium acetate, potassium octoate), organotin compounds (e.g., dibutyltin dilaurate, stannous octoate), quaternary ammonium compounds (e.g., N-(2-hydroxyethyl)trimethylammonium chloride), and the like, and combinations thereof.

[0065] Suitable catalysts are available from Evonik (TEGOAMIN ® amine catalysts, KOSMOS ® metal catalysts, DABCO ® TMR catalysts, DABCO ® K-15 catalyst and POLYCAT ® catalysts), Huntsman (JEFFCAT ® catalysts), King Industries (K-KAT ® catalysts), Momentive (NIAX ® catalysts), Galata Chemicals (FOMREZ ® organotin catalysts), and the like.

[0066] Blowing agent

[0067] When a blowing agent is used in a process for producing rigid PUR or PIR foams, the blowing agent can include aliphatic or cycloaliphatic C4-C6 hydrocarbons, water, mono- and polycarboxylic acids and their salts, tertiary alcohols, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halogenated hydrocarbons, hydrofluoroolefins (HFOs), and the like, and mixtures thereof. For further examples of suitable blowing agents, see U.S. Patent No. 6,359,022, the teachings of which are incorporated herein by reference.

[0068] Examples

[0069] The following examples further detail and illustrate the method of the present application. These examples are merely illustrative of the present application. Those skilled in the art will recognize many variations that are within the spirit and scope of the application and the claims.

[0070] Example 1

[0071] Table 2 shows a comparison profile of the low residual monomeric diol polyester polyol of the present application (Sample 1) based on an equivalent formulation to a prior art polyol (Sample 2). As shown, the total residual monomeric diol in the present application polyol having a total product OH value of 378 is about 5%, whereas the residual present in Sample 2 is 15%, typical commercial products have a total product OH value greater than 350. The total OH contribution of the residual monomeric diol in the present application polyol is less than 25% of the total product OH value.

[0072] Table 2. The present application polyol versus conventional polyol based on the same composition

[0073]

[0074] Sample 1 is according to Figure 1The process flow shown was used to prepare. The raw material weights to prepare the intermediate product of Sample 1 are listed in Table 3. A 5 liter glass reactor equipped with mechanical stirring, nitrogen inlet, packed column, condenser with receiver, and temperature controllers to monitor reactor and column top temperatures was initially charged with 550 grams of PTA, 70 grams of phthalic anhydride, 70 grams of adipic acid, 800 grams of diethylene glycol, and 0.6 grams of catalyst. The reaction was brought to 230°C and the byproduct water was collected in the receiver. When the reaction mixture was free of solids, glycerol, and polyethylene glycol, the remaining diethylene glycol was added and the reaction was continued at 230°C until the target of less than 1 mg KOH / gram of sample acid value was achieved. At the end of the esterification process, the intermediate product showed a viscosity of less than 1000 cp and contained >25% unreacted DEG and glycerol. The excess unreacted DEG and glycerol in the intermediate product was removed using a wiped film evaporator (WFE) at 170°C and 5 mm Hg vacuum. The WFE conditions are listed in Table 3. The inventive polyol Sample 1 was the WFE bottom product, corresponding to the intermediate product after selective stripping of the remaining monomeric diol in the overheads. Table 3c shows the raw materials based on the total amount of diethylene glycol and glycerol removed to the WFE overheads. The calculated functionality of the inventive polyol (Sample 1) was 2.7.

[0075] Sample 2 was prepared using the reaction conditions currently used by commercial producers of aromatic polyester polyols. A 3 liter glass reactor equipped with mechanical stirring, nitrogen inlet, packed column, condenser with receiver, and temperature controllers to monitor reactor and column top temperatures was initially charged with 550 grams of PTA, 70 grams of phthalic anhydride, 70 grams of adipic acid, 511 grams of diethylene glycol, 150 grams of polyethylene glycol, 244 grams of glycerol, and 0.6 grams of catalyst. The reaction mixture was heated to 230°C and the byproduct water was collected in the receiver. As shown in Table 2, the viscosity of the inventive polyol was much lower at the same total product OH value compared to Sample 2, which was prepared with the typical residual diol of the commercial product. The inventive polyol Sample 1 also showed lower levels of residual monomeric diol.

[0076] Table 3. Inventive polyol (Example 1) - from intermediate product to final product (WFE bottom product)

[0077]

[0078] Example 2

[0079] Initially, 5817 grams of PTA, 687 grams of phthalic anhydride, and 8000 grams of diethylene glycol were charged into a 30 liter reactor equipped with mechanical stirring, nitrogen inlet, packed column, condenser with receiver, and temperature controllers for monitoring reactor and overhead temperatures. The reaction was brought to 230°C in the presence of esterification catalyst, and the byproduct water was collected in the receiver. When the reaction mixture became free of solids, 2466 grams of glycerol, 1080 grams of polyethylene glycol, and 4654 grams of diethylene glycol were added, and the reaction was continued at 230°C until the target of less than 1 mg KOH / gram of sample was reached. After the esterification reaction, the resulting intermediate product was cooled and charged into a WFE apparatus. The excess unreacted DEG and glycerol in the intermediate product were removed at 170°C and 5 mmHg vacuum. The WFE conditions are listed in Table 4c. The inventive polyol is the WFE bottoms product after the excess diol in the hot separation of the intermediate product. Table 4d shows the raw materials calculated based on the total amount of removed diethylene glycol and glycerol remaining in the WFE bottoms product. The calculated functionality of the inventive polyol (Example 2) is about 2.4. As shown in Table 4, the inventive polyol Example 2 uniquely contains low residual monomer diol, significantly lower than the residual monomer diol in the commercial product shown in Table 1. The residual monomer diol in Example 2 is less than 5% when the total product hydroxyl value is 310, and the residual monomer diol contributes less than 20% of the total OH in the total OH of the product.

[0080] Table 4. Inventive polyol (Example 2)

[0081]

[0082] Example 3

[0083] Table 5 shows the product profile of low viscosity, low hydroxyl polyols with nominal functionality of 2 and 2.1, where the total product OH value is less than 210. The low OH material was made from terephthalic acid, phthalic anhydride, adipic acid, diethylene glycol, and a small amount of polyethylene glycol. To functionalize the low OH polyol, glycerol can be added, as shown in Example 4. In both examples, the intermediate product was formed after esterification of the acid with DEG and / or glycerol at a diol / acid ratio of about 2 at 225°C. The residual diol was hot separated in WFE at 170°C and 4 mmHG. In both cases, the resulting product in the WFE stream contained less than 3% of low residual monomer diol, and the OH contributed less than 20% of the total product OH.

[0084] Table 5. Inventive polyols with OH values between 180 and 210

[0085]

[0086] Example 4. Comparative foam test of samples 6 to 12.

[0087] Closed cell polyurethane foams were produced from the inventive polyols to achieve comparable performance to prior art polyols, including commercial products listed in Table 1 and / or polyols prepared in the laboratory outside the scope of the present invention. The polymer MDI or A side used in this study was Rubinate M (Huntsman) with an NCO content of 31.2%, a functionality of 2.7, and a viscosity of 190 cp at 25°C. Polyol blends (or B side) containing aromatic polyester and / or polyether polyols, flame retardant, surfactant, catalyst, blowing agent, and water were prepared. The A side and B side were pre-cooled to 20°C or less (such as 15°C or 18°C) for at least 1 hour. After temperature equilibration, the A side and B side were mixed in a mixing cup of appropriate size in a 1 : 1 weight ratio. The combined mixture was agitated using a motor driven stir blade rotating at 3500 rpm for 3-5 seconds and poured into an appropriate box based on the total weight of the foam. The reactivity profile was obtained by measuring the emulsion time, gel time, and skin time.

[0088] Table 6 lists various inventive polyols used to produce hand mixed foams for performance studies in a hand mixed spray formulation compared to prior commercial products shown in Table 1. For samples 6, 7, 9, 10, 11, and 12, the intermediate product was first produced using a similar apparatus described in the preparation of sample 1 and the residual monomer diol was thermally removed under vacuum to produce an aromatic polyester polyol with low residual monomer diol. The residual monomer diol for the inventive polyol samples (samples 6, 7, 9, 10, 11, 12) is shown in Table 6. These inventive polyols contain low residual diol where the OH contribution of the residual diol is less than 20%. Sample 8, which is not an inventive polyol, was prepared using a similar method as sample 2.

[0089] Table 6. Other examples of inventive polyols

[0090]

[0091] Samples 6-12 were used to prepare hand mixed foams using a typical spray formulation where the A side (isocyanate) was mixed with the B side in a 1 : 1 weight ratio. The description of various B sides used to prepare the hand mixed spray foams is listed in Table 7. To prepare the foams, the combined A side and B side mixture was agitated using a motor driven stir blade rotating at 3500 rpm for 3-5 seconds and poured into an appropriate box based on the total weight of the foam.

[0092] Table 7. B side formulations used for hand mixed foams

[0093]

[0094] Comparative smoke profiles of foams made with the inventive polyols and commercial polyols were tested using an in-house laboratory scale test apparatus (see Table 1 and Table 6). The test apparatus is shown in Figure 2 The foam sample was placed at a fixed 45 degree angle and a Bunsen burner was placed at the lower end of the sample. The flame was applied to the surface of the foam sample for a period of time. The smoke generated during the test was carried by the airflow through the tunnel and measured by a photometer or smoke detector located at the higher end of the tunnel. The signal from the detector was simultaneously collected by a computer to allow further processing of the data. This apparatus allowed comparative measurements of the smoke profile of foam systems made with different polyols under given burning conditions. The test results reported in Table 8 are the average of three to four test runs unless otherwise noted.

[0095] Table 8. Comparative reactivity, density, and smoke data for inventive polyols versus commercial products based on various spray formulation platforms

[0096]

[0097] The smoke comparison data shown in Table 8 demonstrates a continuing decrease in the amount of smoke for hand-mixed spray foam prepared with aromatic polyester polyols containing lower residual diols. As shown in Table 8, the smoke for foams made with the inventive polyols was reduced by 20-35% compared to commercial aromatic polyester polyols and / or aromatic polyester polyols with higher residual diols.

[0098] Green strength of foams prepared using Formulation 1 (see Table 8) was also tested. Green strength measures the ability of a foam to withstand forces before it is fully cured. Following the foaming procedure, the top edge of the foam cup was cut 2:00 minutes after mixing of A and B sides to provide a smooth, flat surface. To measure green strength, enough force was applied to the smooth surface to create a 0.35 inch indentation in the surface of the foam. The green strength of the foam was measured at 3, 4, 5, 6, 8, and 10 minutes after foaming. The test results are shown in Table 9. Figure 3 In general, foams with higher overall functionality exhibited fewer indentations than foams with lower functionality at the same density and reactivity. Figure 3 As shown, the inventive polyol with lower functionality (2.7) exhibited higher green strength compared to the commercial product with functionality of 2.8.

Claims

1. An aromatic polyester polyol comprising: - a total product OH number of 150 to 450; - a viscosity of less than 12,000 cp; - an OH number of residual monomer diol of < 30% of the total product OH number - residual monomer diol in an amount of less than 10 wt%; and - a level of 1,4-dioxane of less than 50 ppm.

2. The aromatic polyester polyol of claim 1, wherein the residual monomer diol is less than 4 wt% when the total product OH number is less than 220.

3. The aromatic polyester of claim 1, wherein the residual monomer diol is less than 6 wt% when the total product OH number is less than 280.

4. The aromatic polyester of claim 1, wherein the residual monomer diol is less than 8 wt% when the total product OH number is less than 350.

5. The aromatic polyester of claim 1, wherein the residual monomer diol is less than 10 wt% when the total product OH number is less than 450.

6. The aromatic polyester polyol of claim 1, wherein the aromatic polyester polyol has a functionality of 1.9 to 4.

7. The aromatic polyester polyol of claim 6, wherein the functionality is 1.9 to 2.

05.

8. The aromatic polyester polyol of claim 1, wherein the total product OH number is less than 200 and the viscosity is less than 10,000 cp.

9. The aromatic polyester polyol of claim 8, wherein the viscosity is less than 8000 cp.

10. The aromatic polyester polyol of claim 1, without the addition of a flame retardant and / or without the admixture of an additive that reduces the polyol's hydroxyl number and viscosity.

11. The aromatic polyester polyol of claim 6, wherein the functionality is greater than 2 to 3.

5.

12. The aromatic polyester polyol of claim 1, wherein the total product OH number is less than or equal to 220 and the residual monomer diol is less than 4 wt%.

13. The aromatic polyester polyol of claim 1, wherein less than 30% of the total product OH number is contributed by the residual monomer diol.

14. The aromatic polyester polyol of claim 13, wherein less than 20% of the total product OH number is contributed by the residual monomer diol.

15. A method comprising: - feeding a feed stream comprising a diol stream and an aromatic stream comprising at least one of an aromatic ester and acid, and a catalyst stream to a reactor, wherein: the diol stream is selected from monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, higher glycols, dipropylene glycol, methylpropanediol, higher molecular weight polyethylene glycols and polypropylene glycols, higher functionality diols such as glycerol, trimethylolpropane, pentaerythritol, glucosides, and alkyl substituted glucosides; and the aromatic acid / ester is selected from terephthalic acid, isophthalic acid, phthalic acid / anhydride, trimellitic anhydride, and their corresponding esters or combinations thereof; - reacting the feed stream in the reactor, thereby forming an intermediate stream comprising aromatic polyester polyol having a total product OH value greater than 250, residual monomeric diol, water, and optionally 1,4-dioxane; and - separating the residual monomeric diol in the intermediate stream into a diol rich overhead stream and a product stream having a total product OH value less than 450, a viscosity less than 12000 cp; and a level of residual monomeric diol less than 10 wt% by a thermal separation process under vacuum; and 16. The method of claim 15, wherein the feed stream further comprises a hydroxyl terminated material.

17. The method of claim 15, wherein the feed stream further comprises at least one of an aliphatic acid / ester, a fatty acid, and a natural oil, wherein the aliphatic acid / ester is selected from succinic acid, glutaric acid, adipic acid, and / or an ester thereof or a combination thereof, the fatty acid is selected from caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, ricinoleic acid, or a mixture thereof, and the natural oil is selected from soybean oil, sunflower oil, castor oil, corn oil, olive oil, palm oil, tall oil, tallow, or a mixture thereof.

18. The method of claim 15, wherein the reaction is conducted at a reaction temperature of 180 °C to 235 °C.

19. The method of claim 15, wherein the vacuum separation is conducted at a temperature of 130 °C to 170 °C and a pressure of 0.1 mmHG to 20 mmHG.

20. The method of claim 16, wherein the hydroxyl terminated material is an alkanolamine selected from diethanolamine, triethanolamine, a substituted ethanolamine, or a mixture thereof.

21. A polyurethane / polyisocyanurate foam comprising: a. the aromatic polyester polyol of claim 1; b. a surfactant; c. a catalyst; d. an isocyanate; and e. a blowing agent.

22. An aliphatic polyester polyol or a mixed aliphatic / aromatic polyester polyol comprising: - a total product OH value of < 120; - a viscosity of less than 20,000 cp; - an OH value of residual monomeric diol of the total product OH value of < 5%; and - residual monomeric diol in an amount of less than 1 wt%.

23. The aliphatic polyester polyol or mixed aliphatic / aromatic polyester polyol of claim 22, wherein the residual monomeric diol is less than 0.5 wt% when the total product OH value is less than 80.

24. The aliphatic polyester polyol or mixed aliphatic / aromatic polyester polyol of claim 22, wherein the aliphatic polyester polyol or the mixed aliphatic / aromatic polyester polyol has a functionality of 1.9 to 4.

25. A method of producing the aliphatic polyester polyol or mixed aliphatic / aromatic polyester polyol of claim 22, the method comprising: - feeding a feed stream comprising a diol stream and an aromatic stream comprising at least one of an aliphatic and / or aromatic ester and acid, and a catalyst stream to a reactor, wherein: the diol stream is selected from monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, higher glycols, dipropylene glycol, methylpropanediol, higher molecular weight polyethylene glycols and polypropylene glycols, higher functionality diols such as glycerol, trimethylolpropane, pentaerythritol, glucosides, and alkyl substituted glucosides, or combinations thereof; and the aliphatic acid / ester and / or aromatic acid is selected from succinic acid, glutaric acid, adipic acid, terephthalic acid, isophthalic acid, phthalic acid / anhydride, trimellitic anhydride, and other diacids / polyacids and their corresponding esters or combinations, - reacting the feed stream in the reactor, thereby forming an intermediate stream with more than 0.8% residual monomeric diol, - separating the excess residual monomeric diol intermediate stream into a diol rich stream in the overhead and the aliphatic polyester polyol or the mixed aliphatic / aromatic polyester polyol by thermal separation methods under vacuum.

26. A polyurethane foam comprising: a. the aliphatic polyester polyol or mixed aromatic polyester polyol of claim 22; b. a surfactant; c. a catalyst; d. an isocyanate; and e. a blowing agent.

27. The method of claim 25, wherein the total product OH value of the intermediate stream is greater than 15% of the total product OH value of the aliphatic polyester polyol or the mixed aliphatic / aromatic polyester polyol.

28. The aliphatic polyester polyol or mixed aliphatic / aromatic polyester polyol of claim 23, wherein the residual monomeric diol is less than 0.1 wt% and the viscosity< 18,000 cp.

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