Isocyanate-reactive composition

Abstract

An isocyanate-reactive composition comprising (i) at least one isocyanate-reactive compound, and (ii) a predetermined amount of at least one thixotropic modifier, and a foam-forming composition for producing a polyurethane or polyisocyanurate foam comprising (A) at least one isocyanate component, and (B) at least one isocyanate-reactive component, wherein the at least one isocyanate-reactive component is the isocyanate-reactive composition described above.

Description

[Technical Field]

[0001] The present invention relates to an isocyanate-reactive composition, a process for preparing said isocyanate-reactive composition, and a foam-forming formulation comprising said isocyanate-reactive composition. [Background technology]

[0002] Introduction Polyurethane foams and methods for producing them are well known. Generally, polyurethane foams are prepared by mixing reactive chemical components, such as an isocyanate component, with an isocyanate-reactive component in the presence of commonly used additives, such as a suitable catalyst and a suitable blowing agent. Typically, polyurethane foams are formed from two separate components: a first component, commonly referred to as the "A-side" component, and a second component, commonly referred to as the "B-side" component. The A-side and B-side components react when the two components come into contact with each other. To prepare conventional polyurethane foams, the first component, or A-side, contains an isocyanate compound, such as a diisocyanate or polyisocyanate, with a high level of highly reactive isocyanate (N=C=O) functionality on the molecule. The second component, or B-side, contains an isocyanate-reactive compound with a functional group reactive with the isocyanate functionality of the isocyanate compound in the A-side component. The isocyanate-reactive compound is generally a polyol with two or more hydroxyl groups. In some cases, a mixture of polyols is used to achieve the desired foaming properties. The overall ratio of NCO groups on the A side to hydroxyl groups on the B side is often varied to achieve different foam properties. For rigid polyurethane foams (PUR foams), the isocyanate index (ISO index), which is the molar ratio of NCO groups to OH groups, is typically greater than 1.0. For example, rigid polyurethane foams have an ISO index of about 1.1 to 1.5, while rigid polyisocyanurate foams (PIR foams) typically have an ISO index of at least 1.5, and more often at least 1.8. The weight ratio of A side to B side depends on the ISO index, the NCO equivalent molecular weight of the A side, and the hydroxyl equivalent molecular weight of the B side; the weight ratio of A side to B side can vary from 4:1 to 1:4.

[0003] To date, rigid polyurethane foams have been produced using various methods known in the art. For example, WO 2013 / 026809(A1) discloses a process for producing polyurethanes by reacting a polyisocyanate with a polyol containing at least one thixotropic agent to solve the phase separation problem when incorporating a copolymer polyol into a rigid foaming system. The thixotropic agent specified in the above reference is based on a solution of a polyamide containing urea groups in an organic solvent.

[0004] WO 2017 / 155863(A1) discloses a rigid polyurethane foam comprising the reaction product of an isocyanate and an isocyanate-reactive thixotropic composition. The thixotropic composition is based on a combination of three polyether polyols with specific structural and rheological properties. The first of the three polyether polyols is an ortho-toluene diamine (o-TDA) type, the second of the three polyols is a polyol requiring 4-5 functionality, and the third of the three polyols is a polyol requiring 5-6 functionality. No thixotropic additives or fillers are used or taught in WO 2017 / 155863(A1).

[0005] U.S. Patent Application No. 2012 / 0183694(A1) discloses spray foam formulations containing rheology modifiers. The rheology modifiers are used to resist the mobility of the uncured formulation after it is sprayed, allowing it to expand and cure. Different types of rheology modifiers are described in U.S. Patent Application No. 2012 / 0183694(A1), with modified nanoclay rheology modifiers disclosed as being most effective at providing sag resistance. U.S. Patent Application No. 2012 / 0183694(A1) does not mention any use of rheology modifiers to improve thermal insulation properties or mechanical crushability. Summary of the Invention

[0006] One aspect of the present invention is directed to an isocyanate-reactive composition comprising (i) at least one isocyanate-reactive compound and (ii) an amount of at least one thixotropy modifier, such as microfibrillated cellulose.

[0007] In one embodiment, the at least one isocyanate-reactive compound, component (i), of the isocyanate-reactive composition is at least one polyester polyol compound.

[0008] In another embodiment, the at least one isocyanate-reactive compound, component (i), is at least one polyester polyol compound, and the polyester polyol compound is at least 30 pts, based on the total weight of all isocyanate-reactive compounds in 100 parts by weight in the isocyanate-reactive composition.

[0009] In yet another embodiment, the isocyanate-reactive composition comprises (i) at least one isocyanate-reactive compound, and (ii) at least one thixotropy modifier, wherein the at least one thixotropy modifier is a cellulose ether, and the cellulose ether is methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, and mixtures thereof.

[0010] In yet another embodiment, the amount of the at least one thixotropy modifier, component (ii), is from 0.01 parts by weight to 5 parts by weight, based on the total weight of all isocyanate-reactive compounds in 100 parts by weight in the isocyanate-reactive composition.

[0011] Another aspect of the present invention is directed to a process for producing the above isocyanate-reactive composition, comprising the steps of combining (i) at least one isocyanate-reactive compound and (ii) a predetermined amount of at least one thixotropy modifier, such as microfibrillated cellulose.

[0012] Yet another aspect of the present invention is directed to a foam-forming composition for producing polyurethane or polyisocyanurate foams, comprising (A) at least one isocyanate component and (B) at least one isocyanate-reactive component, wherein the at least one isocyanate-reactive component, component (B), comprises the isocyanate-reactive composition described above. Foam-forming compositions comprising the isocyanate-reactive component in component (B) are particularly useful for making polyurethane rigid (PUR) foams, polyisocyanurate rigid (PIR) foams, or a combination of both PIR and PUR foams with improved thermal insulation performance and mechanical toughness.

[0013] Yet another aspect of the present invention is directed to a process for producing a foam-forming composition for producing polyurethane or polyisocyanurate foam, comprising combining (A) at least one isocyanate component and (B) at least one isocyanate-reactive component, wherein the at least one isocyanate-reactive component comprises the isocyanate-reactive composition described above.

[0014] Yet another aspect of the present invention is directed to rigid polyurethane or polyisocyanurate foams made from the above-described foam-forming compositions. DETAILED DESCRIPTION OF THE INVENTION

[0015] As used herein, "thixotropy modifier" or "thixotropic agent" refers to an organic or inorganic material that exhibits a stable form at rest but becomes fluid when agitated. A thixotropic fluid requires a finite time to achieve equilibrium viscosity when subjected to a sudden change in shear rate. Such behavior is generally referred to as thixotropic flow, characterized by time-dependent shear thinning. Many gels and colloids are thixotropic materials. Thixotropy arises because particles or structural solutes require time to organize, as explained by Mewis and Wagner, "Thixotropy." Advances in Colloid and Interface Science. 147-148:214-227 (2009).

[0016] "Fibril" herein refers to a structural material that has the large aspect ratio, such as length to diameter, of a fiber or filament. Fibrils tend to have diameters in the range of 10 nm to 100 nm. Fibrils are not usually found alone, but as part of larger hierarchical structures commonly found in biological systems.

[0017] "Microfibrillated cellulose" (abbreviated herein as "microfibrillated cellulose, MFC") is a cellulose polymer, a naturally occurring linear polymer made up of repeating units of glucose. Single polymers stack together to form fibrils, and these fibrils stack together again to form the naturally occurring cellulose fiber structure. This supramolecular structure consists of both crystalline and amorphous regions. MFC is also called nanocellulose, cellulose nanofiber (CNF), or cellulose nanocrystal (CNC).

[0018] As used throughout this specification, the following abbreviations have the following meanings, unless the context clearly indicates otherwise: "=" means "equal to", @ means "at", "<" means "less than", ">" means "greater than", "≦" means "less than or equal to", "≧" means "greater than or equal to", g = grams, mg = milligrams, pts = parts by weight, kg = kilogram, g / cc = grams per cubic centimeter, kg / m 3 = kilograms per cubic meter, g / eq = grams per equivalent weight, g / mol = grams per mole, mg KOH / g = the acid number of a chemical measured as the number of milligrams of potassium hydroxide needed to neutralize 1 gram of the chemical, mg KOH / g = milligrams of potassium hydroxide per gram, L = liter, mL = milliliter, g / L = grams per liter, Mw = molecular weight by mass, m = meters, μm = microns, mm = millimeters, cm = centimeters, nm = nanometers, min = minutes, s = seconds, rad / s = radians per second, ms = milliseconds, hr = hours, mm / min = millimeters per minute, m / s = meters per second, °C = degrees Celsius, mPa.s = millipascal-second, mPa = megapascal, kPa = kilopascal, GPa = gigapascal, Pa.s / m 2 = Pascal seconds per square metre, cN = centinewtons, rpm = revolutions per minute, mm 2 = square millimeters, mW / mK = milliwatts per meter-Kelvin, g / 10min = grams per 10 minutes, % = percent, eq% = equivalent percent, vol% = volume percent, and wt% = weight percent.

[0019] Unless otherwise specified, all percentages, parts, ratios, and other amounts are defined by weight. For example, all percentages set forth herein are weight percentages (wt %) unless otherwise indicated.

[0020] Temperatures are given in degrees Celsius (°C), and "ambient temperature" means 20°C to 25°C unless otherwise specified.

[0021] As previously mentioned, polyurethane or polyisocyanurate foams are formed by reacting a first component (A), commonly referred to as the "A-side" component, with a second component (B), commonly referred to as the "B-side" component. The A-side component contains at least one isocyanate compound, such as a diisocyanate or polyisocyanate, and the B-side component contains at least one isocyanate-reactive compound having a functional group that is reactive with the isocyanate functionality of the isocyanate compound in the A-side component.

[0022] One broad embodiment of the present invention comprises a B-side component comprising an isocyanate-reactive composition comprising a mixture of (Bi) at least one isocyanate-reactive compound and (Bii) a predetermined amount of at least one thixotropic modifier. The mixture of compounds (Bi) and (Bii) forming the isocyanate-reactive composition can then be used as the B-side component of a polyurethane or polyisocyanurate foam-forming composition comprising a reactive mixture of an A-side component and a B-side component.

[0023] Isocyanate-reactive compositions for making rigid polyurethane or polyisocyanurate foams with improved thermal insulation performance and mechanical toughness include a thixotropic modifier such as MFC, and in one general embodiment, (1) the amount of thixotropic modifier is from 0.01 pts to 5 pts based on the total weight of the isocyanate-reactive compounds at 100 pts; (2) the average functionality of the isocyanate-reactive groups is 3 or less, more preferably in the range of 1.8 to 2.7; and (3) the ratio of the viscosities measured at 0.1 rad / sec and 100 rad / sec on the isocyanurate-reactive composition at 60°C is greater than 10 but less than or equal to 300.

[0024] Generally, the thixotropy modifier can be introduced into the isocyanate-reactive composition, component (B), in various forms such as the pure material (e.g., as a solid powder), or as part of a solution, dispersion, or paste, or any combination thereof, to provide the amount of thixotropy modifier in component (B) within the aforementioned range of 0.01 pts to 5 pts, based on the total weight of the isocyanate-reactive compounds in 100 pts.

[0025] Rigid polyurethane or polyisocyanurate foams prepared from a reactive mixture of (A) a polymeric isocyanate, having in one embodiment an Isocyanate Index of 1.0 or greater, and in another embodiment in the range of 1.1 to 7, (B) the isocyanate-reactive composition described above, and (C) optionally auxiliary or additional ingredients consisting of surfactants, foaming catalysts, physical or chemical blowing agents, flame retardant additives, nucleating agents, and the like, beneficially exhibit low thermal conductivity and improved mechanical toughness. In a preferred embodiment, the thermal conductivity of the foam is 19.5 mW / mK or less at 10°C, and the mechanical friability of the foam is 10% or less.

[0026] Optional auxiliary or additional ingredients can be added to the A-side and / or B-side components of the foam-forming composition, as needed. In preferred embodiments, the optional auxiliary or additional ingredients can include, for example, (C) a blowing agent and / or catalyst. In some embodiments, auxiliary ingredients such as urethane catalysts, trimerization catalysts, surfactants, reactive or non-reactive diluents, physical or chemical blowing agents, antioxidants, flame retardant additives, pigments, adhesion promoters, and the like can be used in the present invention.

[0027] The isocyanate component, component (A) (or A-side component) of the present invention can include, for example, one or more isocyanate compounds, including, for example, polyisocyanates. As used herein, "polyisocyanate" refers to molecules having an average of greater than 1.0 isocyanate groups / molecule, for example, an average functionality greater than 1.0.

[0028] The isocyanate compounds useful in the present invention can be aliphatic polyisocyanates, cycloaliphatic polyisocyanates, araliphatic polyisocyanates, aromatic polyisocyanates, or combinations thereof. Examples of isocyanates useful in the present invention include polymethylene polyphenylisocyanate, toluene 2,4- / 2,6-diisocyanate (TDI), methylenediphenyl diisocyanate (MDI), polymeric MDI, triisocyanatononane (TIN), naphthyl diisocyanate (NDI), 4,4'-diisocyanatodicyclohexyl-methane, 3-isocyanatomethyl-3,3,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate IPDI), tetramethylene diisocyanate, hexamethylene diisocyanate, among others. diisocyanate (HDI), 2-methyl-pentamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate (THDI), dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 4,4'-diisocyanato-3,3'-dimethyl-dicyclohexylmethane, 4,4'-diisocyanato-2,2-dicyclohexylpropane, 3-isocyanatomethyl-1-methyl-1-isocyanatocyclohexane (MCI), 1,3-diisooctylcyanato-4-methylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, and combinations thereof. In addition to the isocyanates mentioned above, partially modified polyisocyanates containing, among others, uretdione, isocyanurate, carbodiimide, hexamethylimine, allophanate, or biuret structures, and combinations thereof, may also be utilized in the present invention.

[0029] The isocyanate may be polymeric. As used herein, "polymeric" refers to higher molecular weight homologs and / or isomers in describing the isocyanate. For example, polymeric methylene diphenyl isocyanate refers to higher molecular weight homologs and / or isomers of methylene diphenyl isocyanate.

[0030] In another embodiment, the isocyanate component useful in the present invention may comprise an isocyanate prepolymer, which is known in the art and is generally prepared by reacting (1) at least one isocyanate compound with (2) at least one polyol compound.

[0031] As previously mentioned, the isocyanate can have an average functionality of greater than 1.0 isocyanate groups / molecule. For example, the isocyanate can have an average functionality of 1.75 to 3.50. All individual values ​​and subranges between 1.75 and 3.50 are included, for example, the isocyanate can have an average functionality ranging from a lower limit of 1.75, 1.85, or 1.95 to an upper limit of 3.50, 3.40, or 3.30.

[0032] The isocyanate may have an isocyanate equivalent weight of 80 g / eq to 300 g / eq, including all individual values ​​and subranges between 80 g / eq and 300 g / eq, for example, the isocyanate may have a lower isocyanate equivalent weight of 80 g / eq, 90 g / eq, or 100 g / eq to an upper limit of 300 g / eq, 290 g / eq, or 280 g / eq.

[0033] The isocyanates used in the present invention can be prepared by known processes, for example, polyisocyanates can be prepared by phosgenation of the corresponding polyamine with the formation of a polycarbamoyl chloride and its thermal decomposition to provide a polyisocyanate and hydrogen chloride, or in another embodiment, polyisocyanates can be prepared by a phosgene-free process, for example, by reacting the corresponding polyamine with urea and an alcohol to obtain a polycarbamate and its thermal decomposition to yield, for example, a polyisocyanate and an alcohol.

[0034] The isocyanates used in the present invention are commercially available. Examples of commercially available isocyanates useful in the present invention include, but are not limited to, VORANATE™, PAPI™, and ISONATE™ trade name polyisocyanates, such as VORANATE™ M220 and PAPI™ 27, among other commercially available isocyanates, all of which are available from The Dow Chemical Company.

[0035] The amount of isocyanate compound used in the reactive foam-forming composition of the present invention can be, for example, 20% to 80% by weight in one embodiment, 25% to 75% by weight in another embodiment, and 30% to 70% by weight in yet another embodiment.

[0036] The isocyanate-reactive component of the present invention, component (B) (or B-side component), comprises an isocyanate-reactive composition that is a mixture, combination, or blend of (Bi) at least one isocyanate-reactive compound and (Bii) an amount of at least one thixotropic modifier.

[0037] The isocyanate-reactive compound (Bi) can be, for example, one or more compounds that react with the isocyanate compounds present in the A-side component. The isocyanate-reactive compound includes, for example, polyol compounds including polyether polyols, polyester polyols, polyester ether polyols, polycarbonate polyols, polyacrylate polyols, polycaprolactone polyols, natural oil polyols, and blends thereof. In a preferred embodiment, the polyol compound can be selected from the group consisting of polyether polyols, polyester polyols, polyester ether polyols, and mixtures thereof. The polyol compound (Bi) can also include other polyols, such as alkylene glycol chain extenders. The polyol compound (Bi) can, for example, in one embodiment, include a single polyol or a mixture or blend of two or more different polyols. As used herein, "polyol" refers to a compound having an average hydroxyl functionality of 1.8 or greater, such as a diol, triol, tetrol, etc. The functionality (average number of isocyanate-reactive groups / molecule) of the polyol compound may be, for example, at least 1.8 in one embodiment, and at least 2.0 in another embodiment.

[0038] Any number of different polyols, such as those discussed herein, among others known to those skilled in the art, can be utilized for the polyol compound. For example, the polyol compound (Bi) useful in the present invention can include one or more embodiments of polyol compounds such as aromatic polyester polyols, triols or polyether triols such as glycerol, sucrose / glycerin-initiated polyether polyols, sorbitol-initiated polyether polyols, amine-initiated polyols, and mixtures thereof.

[0039] Generally, the average hydroxyl functionality of the polyol compounds useful in the present invention, as described above, can range from as low as less than 1.8 to as high as 7.5. For example, aromatic polyester polyols can have an average hydroxyl functionality of 1.8 to 3.0, and sucrose / glycerin-initiated polyether polyols can have an average hydroxyl functionality of 3.5 to 7.5. Thus, the average hydroxyl functionality of the polyol compounds used in the present invention can range from 1.8 to 7.5. All individual values ​​and subranges between 1.8 and 7.5 are included. For example, polyol compounds can have an average hydroxyl functionality ranging from a lower limit of 1.8, 2.0, 3.0, or 3.5 to an upper limit of 7.5, 7.0, 6.5, or 6.0.

[0040] Generally, the polyol compound can have an average hydroxyl number in the range of 75 mg KOH / g to 650 mg KOH / g, including all individual values ​​and subranges between 75 mg KOH / g and 650 mg KOH / g, for example, the polyol compound can have an average hydroxyl number from a lower limit of 75 mg KOH / g, 80 mg KOH / g, 100 mg KOH / g, 150 mg KOH / g, or 175 mg KOH / g to an upper limit of 650 mg KOH / g, 600 mg KOH / g, 500 mg KOH / g, or 450 mg KOH / g.

[0041] Generally, the polyol compound can have a number average molecular weight of 100 g / mol to 1,500 g / mol, including all individual values ​​and subranges from 100 g / mol to 1,500 g / mol, for example, a polyol compound can have a number average molecular weight of from a lower limit of 100 g / mol, 150 g / mol, 175 g / mol, or 200 g / mol to an upper limit of 1,500 g / mol, 1250 g / mol, 1,000 g / mol, or 900 g / mol.

[0042] Generally, the polyol compound can have a hydroxyl equivalent molecular weight of from 50 g / eq to 750 g / eq, including all individual values ​​and subranges between 50 g / eq and 750 g / eq, for example, the polyol compound can have a hydroxyl equivalent molecular weight of from a lower limit of 50 g / eq, 90 g / eq, 100 g / eq, or 110 g / eq to an upper limit of 350 g / eq, 300 g / eq, 275 g / eq, or 250 g / eq.

[0043] As used herein, "aromatic polyester polyol" refers to a polyester polyol containing an aromatic ring. For example, the aromatic polyester polyol may be a phthalic anhydride diethylene glycol polyester or may be prepared using an aromatic dicarboxylic acid together with a glycol. The aromatic polyester polyol may be, for example, a hybrid polyester-polyether polyol, such as those discussed in WO 2013 / 053555.

[0044] In one embodiment, the aromatic polyester polyol can be prepared using known equipment and reaction conditions. In another embodiment, the aromatic polyester polyol can be commercially available. Examples of commercially available aromatic polyester polyols include, but are not limited to, several polyols sold under the trade name STEPANPOL (trademark), such as STEPANPOL (trademark) PS-2352, available from Stepan Company.

[0045] One or more embodiments of the present invention may include a polyol compound comprising a triol. The triol may have an average hydroxyl functionality of 3.0. The triol may be a polyether or polyester triol. For example, the triol may be glycerol.

[0046] In one embodiment, the triol can be prepared using known equipment and reaction conditions. In another embodiment, the triol can be obtained commercially. Examples of commercially available triols include, but are not limited to, several polyols sold under the trade name VORATEC™, such as VORATEC™ SD 301, available from The Dow Chemical Company, among others.

[0047] One or more embodiments of the present invention may include a polyol compound comprising a sucrose / glycerin-initiated polyether polyol. The sucrose / glycerin-initiated polyether polyol may include structural units derived from another alkylene oxide, such as ethylene oxide. The sucrose / glycerin-initiated polyether polyol may include structural units derived from styrene-acrylonitrile, polyisocyanate, and / or polyurea.

[0048] In one embodiment, the sucrose / glycerin-initiated polyether polyol can be prepared using known equipment and reaction conditions. For example, the sucrose / glycerin-initiated polyether polyol can be formed from a reaction mixture including sucrose, propylene oxide, and glycerin. One or more embodiments provide that the sucrose / glycerin-initiated polyether polyol is formed via the reaction of sucrose with propylene oxide. In another embodiment, the sucrose / glycerin-initiated polyether polyol can be commercially obtained. Examples of commercially available sucrose / glycerin-initiated polyether polyols include, but are not limited to, several polyols sold under the VORANOL™ trade name, such as VORANOL™ 360, VORANOL™ 490, and VORANOL™ 280, available from The Dow Chemical Company, among others.

[0049] One or more embodiments of the present invention may include a polyol compound comprising a sorbitol-initiated polyether polyol. In one embodiment, the sorbitol-initiated polyether polyol may be prepared using known equipment and reaction conditions. For example, the sorbitol-initiated polyether polyol may be formed from a reaction mixture comprising sorbitol and an alkylene oxide, such as ethylene oxide, propylene oxide, and / or butylene oxide. The sorbitol-initiated polyether polyol may be capped; for example, the addition of alkylene oxide may be performed to preferentially place or cap a particular alkylene oxide at a desired position in the polyol.

[0050] In another embodiment, sorbitol-initiated polyether polyols can be obtained commercially. Examples of commercially available sorbitol-initiated polyether polyols include, but are not limited to, several polyols sold under the trade name VORANOL™, such as VORANOL™ RN 482, available from The Dow Chemical Company, among others.

[0051] One or more embodiments of the present invention may include a polyol composition comprising an amine-initiated polyol. The amine-initiated polyol may be initiated with an aromatic amine or an aliphatic amine, for example, the amine-initiated polyol may be, among others, an orthotoluenediamine (o-TDA)-initiated polyol, an ethylenediamine-initiated polyol, a diethylenetriamine-initiated polyol, a triisopropanolamine-initiated polyol, or a combination thereof.

[0052] In one embodiment, the amine-initiated polyol can be prepared using known equipment and reaction conditions. For example, the amine-initiated polyol can be formed from a reaction mixture containing an aromatic or aliphatic amine and an alkylene oxide, particularly, for example, ethylene oxide and / or butylene oxide. The alkylene oxide can be added to the alkoxylation reactor in one step or sequentially over several steps, and each step can use a single alkylene oxide or a mixture of alkylene oxides.

[0053] Generally, the concentration of the isocyanate-reactive compound, such as polyol compound (Bi), used in the isocyanate-reactive composition, component B, of the reactive foam-forming compositions of the present invention can be, for example, from 95% to 99.99% by weight in one embodiment, from 95% to 99.9% by weight in another embodiment, from 95% to 99% by weight in yet another embodiment, from 95% to 99% by weight in yet another embodiment, from 97% to 99% by weight in yet another embodiment, and from 97.5% to 99% by weight in yet another embodiment, based on the total weight of the components in the isocyanate-reactive composition, component (B).

[0054] The thixotropy modifier compound (Bii) used in the isocyanate-reactive composition, component (B), of the reactive foam-forming composition of the present invention can be, for example, one or more compounds including, for example, MCF; nanocellulose; cellulose ether materials such as methylcellulose, ethylcellulose, hydroxyethylcellulose; starch; associative polymers; and mixtures thereof.

[0055] Inorganic compounds such as silica and organically modified sheet silicates can also be used as thixotropic agents. Incorporation of inorganic thixotropic agents into isocyanate-reactive compositions can be a little more difficult than with MCF-type materials because cellulosic materials interact better with polyols.

[0056] In one preferred embodiment, the thixotropy modifier compound may include MFC, hydroxyethyl cellulose, nanocrystalline cellulose, and mixtures thereof.

[0057] In another preferred embodiment, the thixotropy modifier compound may include commercially available compounds such as CELLOSIZE™ Hydroxyethyl Cellulose (HEC) (available from The Dow Chemical Company), MFC pastes in water such as EXILVA™ P01V and EXILVA™ F01V (products by Borregaard), and mixtures thereof.

[0058] The MFC useful in the present invention can be prepared from any cellulose raw material, such as wood pulp. In a preferred embodiment, wood pulp is used to prepare the MFC. Nanocellulose fibrils can be isolated from wood-based fibers using mechanical methods, such as exposing the pulp to high shear forces to separate larger wood fibers into nanofibers. Mechanical methods and devices for forming the MFC can include, for example, high-pressure homogenizers, ultrasonic homogenizers, grinders, or microfluidizers. In a preferred embodiment, a homogenizer is used to peel the cell walls of the fibers, liberating the nano-sized fibrils that form the MFC.

[0059] MFC is insoluble in water, has a high aspect ratio, and has a high surface area compared to conventional cellulose fibers. In aqueous suspension, MFC creates a particle-fibril network. MFC consists of long, interconnected fibrils, and the resulting flexible MFC particles create a strong network with high water retention efficiency.

[0060] MFC pastes, such as EXILVA™, are three-dimensional networks of cellulose microfibrils suspended in water. The microfibrils form flexible aggregates with a high surface area that allows for highly efficient interaction with the surroundings / matrix. This can be advantageous when using MFC as a rheology modifier.

[0061] MFC, which contains both crystalline and amorphous regions, possesses impressive mechanical properties, including high modulus and tensile strength. Nano-sized crystalline cellulose materials have been measured to exhibit Young's modulus of 150 GPa and tensile strength of 10 GPa. The use of MFC in applications will depend on the type of end use and the desired functionality in a particular product formulation. However, MFC offers significant opportunities for developing new formulations in various fields, contributing novel properties to products and providing a green profile for products.

[0062] The amount of thixotropy modifier compound used in component (B) of the reactive composition of the present invention can be, for example, from 0.01 pts to 5 pts in one embodiment, from 0.1 pts to 4 pts in another embodiment, from 0.2 pts to 3 pts in yet another embodiment, and from 0.5 pts to 2.5 pts in yet another embodiment, based on the total weight of the polyol compounds in the isocyanate-reactive composition, component (B), in 100 pts.

[0063] The average functionality of the isocyanate-reactive groups in component (B) of the present invention is 3.0 or less in one embodiment, in the range of 1.8 to 2.7 in another embodiment, in the range of 2.0 to 2.7 in yet another embodiment, and in the range of 2.0 to 2.5 in yet another embodiment.

[0064] The ratio of viscosities measured at 60°C for the isocyanate-reactive composition, i.e., the combination of (Bi) at least one isocyanate-reactive compound and (Bii) at least one thixotropic modifier, at two shear rates: (1) 0.1 rad / sec and (2) 100 rad / sec, is greater than 10 and less than 300 in one embodiment, between 15 and 250 in another embodiment, and between 20 and 200 in yet another embodiment. If the viscosity ratio is too small (e.g., less than 10), the viscosity of the isocyanate-reactive composition is not high enough to be effective in enhancing cell stability during the initial stages of the foaming process. Conversely, if the viscosity ratio is too large (e.g., greater than 300), the viscosity of the isocyanate-reactive composition at rest is too high to allow cells to expand into the desired low-density foam.

[0065] In addition to the above-described components (A) and (B) present in the foam-forming reactive mixture, the reactive mixture of the present invention may also include other additional optional auxiliary components, compounds, agents, or additives as component (C). Such optional component (C) may be added to the reactive mixture with either component (A) and / or (B), or may be added as a separate addition as component (C). The optional auxiliary components, compounds, agents, or additives that may be used in the present invention may include one or more optional compounds known in the art for their use or function. For example, optional component (C) may include expandable graphite, physical or chemical blowing agents, foaming catalysts, flame retardants, emulsifiers, antioxidants, surfactants, liquid nucleating agents, solid nucleating agents, Ostwald ripening retarding additives, pigments, solvents further comprising a solvent selected from the group consisting of ethyl acetate, methyl ether ketone, toluene, and mixtures of two or more thereof, and mixtures of two or more of the above-described optional additives.

[0066] The amount of optional compounds used to add to the reactive mixture of the present invention may be, for example, 0 to 50 pts based on 100 pts of the total polyol amount on the B-side in one embodiment, 0.1 to 40 pts in another embodiment, and 1 to 35 pts in yet another embodiment. For example, in one embodiment, the amount of physical blowing agent used, if used, may be 1 to 40 pts based on 100 pts of the total polyol amount on the B-side. In another embodiment, the amount of chemical blowing agent used, if used, may be 0.1 to 10 pts based on 100 pts of the total polyol amount on the B-side. In yet another embodiment, the amount of flame retardant additive used, if used, may be 5 to 25 pts based on 100 pts of the total polyol amount on the B-side. In yet another embodiment, the amount of surfactant used, if used, is typically 0.1 to 10 pts based on 100 pts of the total polyol amount on the B-side. In yet another embodiment, the amount of foaming catalyst used, if used, is 0.05 pts to 5 pts based on 100 pts of the total polyol amount of Side B. Also, in a typical embodiment, the amount of other additives used, if used, can be 0.1 pts to 5 pts based on 100 pts of the total polyol amount of Side B.

[0067] The isocyanate-reactive composition disclosed herein, component (B), can include a catalyst; for example, a catalyst can be added to the isocyanate-reactive composition. The catalyst can be a blowing catalyst, a gelling catalyst, a trimerization catalyst, or a combination thereof. As used herein, blowing catalysts and gelling catalysts can be distinguished by their tendency to favor either the urea (blow) reaction in the case of a blowing catalyst, or the urethane (gel) reaction in the case of a gelling catalyst. A trimerization catalyst can be utilized to enhance the isocyanurate reaction in the composition.

[0068] Examples of blowing catalysts include catalysts that may tend to favor the blowing reaction, including, but not limited to, short-chain tertiary amines or tertiary amines containing oxygen. Amine-based catalysts may not be sterically hindered. For example, blowing catalysts include, among others, bis-(2-dimethylaminoethyl)ether, pentamethyldiethylene-triamine, triethylamine, tributylamine, N,N-dimethylaminopropylamine, dimethylethanolamine, N,N,N',N'-tetramethylethylenediamine, and combinations thereof. An example of a commercially available blowing catalyst is POLYCAT™ 5 from Evonik, among other commercially available blowing catalysts.

[0069] Examples of gelation catalysts include catalysts that may tend to favor the gel reaction, including, but not limited to, organometallic compounds, cyclic tertiary amines, long-chain amines such as those containing several nitrogen atoms, and combinations thereof. Organometallic compounds include organic compounds such as tin(II) salts of organic carboxylic acids, including, for example, tin(II) diacetate, tin(II) dioctanoate, tin(II) diethylhexanoate, and tin(II) dilaurate; dialkyltin(IV) salts of organic carboxylic acids, including, for example, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, and dioctyltin diacetate, and mixtures thereof. Bismuth salts of organic carboxylic acids, such as bismuth octanoate, can also be used as gelation catalysts. Cyclic tertiary amines and / or long-chain amines include dimethylbenzylamine, triethylenediamine, and combinations thereof. Examples of commercially available gelling catalysts include POLYCAT™ 8 and DABCO™ T-12 from Evonik, among other commercially available gelling catalysts.

[0070] Examples of trimerization catalysts include, among others, PMDETA-N,N,N',N'',N''-pentamethyldiethylenetriamine, N,N',N''-tris(3-dimethylaminopropyl)hexahydro-S-triazine, N,N-dimethylcyclohexylamine, 1,3,5-tris(N,N-dimethylaminopropyl)-S-hexahydrotriazine, [2,4,6-tris(dimethylaminomethyl)phenol], potassium acetate, potassium octanoate, tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, alkali metal hydroxides such as sodium hydroxide, alkali metal alkoxides such as sodium methoxide and potassium isopropoxide, and alkali metal salts of long-chain fatty acids having 10 carbon atoms to 20 carbon atoms, and combinations thereof. Some commercially available trimerization catalysts include DABCO™ TMR-2, DABCO™ TMR-7, DABCO™ K 2097; DABCO™ K15, POLYCAT™ 41, and POLYCAT™ 46, among other commercially available trimerization catalysts, all of which are available from Evonik.

[0071] The amount of catalyst, if used, can be from 0.05 pst to 5.0 pst of isocyanate-reactive composition, based on 100 pst of total polyol parts. All individual values ​​and subranges from 0.05 pst to 5 pst are included. For example, the catalyst can be from a lower limit of 0.05 pst, 0.1 pst, or 0.3 pst to an upper limit of 5.0 pst, 4 pst, or 3.5 pst of isocyanate-reactive composition, based on 100 pst of total isocyanate-reactive compounds in the isocyanate-reactive composition.

[0072] Various conventional blowing agents can be used, for example, the blowing agent can be one or more of water, various hydrocarbons, various hydrofluorocarbons, various hydrofluoroolefins, formic acid, various chemical blowing agents that produce nitrogen or carbon dioxide under the conditions of the foaming reaction, and the like, and mixtures thereof.

[0073] Chemical blowing agents, such as water, can be used alone or in combination with other chemical and / or physical blowing agents. Physical blowing agents, such as low-boiling hydrocarbons, can also be used. Examples of such liquids include alkanes such as heptane, hexane, n- and isopentane, technical-grade mixtures of n- and isopentane, n- and isobutane, and propane, cycloalkanes such as cyclopentane and / or cyclohexane, ethers such as furan, dimethyl ether, and diethyl ether, ketones such as acetone and methyl ethyl ketone, alkyl carboxylates such as methyl formate, dimethyl oxalate, and ethylene lactate, and halogenated hydrocarbons such as methylene chloride, dichloromonofluoromethane, difluoromethane, trifluoromethane, difluoroethane, tetrafluoroethane, chlorodifluoroethane, 1,1-dichloro-2,2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane, pentafluoropropane, heptafluoropropane, and hexafluorobutene, and Honeywell's SOLSTICE™ LBA. Mixtures of these low boiling point liquids with each other and / or with other substituted or unsubstituted hydrocarbons may also be used. Organic carboxylic acids such as formic acid, acetic acid, oxalic acid, Ricinolsau-Re, and carboxyl-containing compounds are also suitable.

[0074] The isocyanate-reactive composition disclosed herein, component (B), can include a surfactant; for example, a surfactant can be added to the isocyanate-reactive composition. The surfactant can be a cell-stabilizing surfactant. Examples of surfactants useful in the present invention include silicon-based compounds such as organosilicone-polyether copolymers, e.g., polydimethylsiloxane-polyoxyalkylene block copolymers, e.g., polyether-modified polydimethylsiloxane, and combinations thereof. Examples of surfactants include non-silicone organic surfactants such as VORASURF™ 504, available from The Dow Chemical Company. Surfactants are commercially available, including those available under trade names such as NIAXT™ (e.g., NIAX™ L 6988) and TEGOSTAB™ (e.g., TEGOSTAB™ B 8462).

[0075] The amount of surfactant, if used, can be from 0.1 pst to 10.0 pst of isocyanate-reactive composition, based on 100 pst of the total polyol combination in the isocyanate-reactive composition. All individual values ​​and subranges between 0.1 pst and 10.0 pst are included, for example, the surfactant can be derived from a lower limit of 0.1 pst, 0.2 pst, or 0.3 pst to an upper limit of 10.0 pst, 9.0 pst, 7.5 pst, or 6 pst of the isocyanate-reactive composition, based on 100 pst of the total polyol combination present in the isocyanate-reactive composition.

[0076] In a broad embodiment, the process for producing the isocyanate-reactive composition of the present invention, component (B) (or B-side component), comprises mixing, combining, or blending (Bi) at least one isocyanate-reactive compound selected from one or more of the compounds described above, (Bii) a predetermined amount of at least one thixotropic modifier compound selected from one or more of the compounds described above, and (Biii) optional components, as needed. The compounds (Bi) through (Biii) are mixed together under process conditions such that the compounds are thoroughly mixed together to form a homogeneous isocyanate-reactive composition. The components that make up the isocyanate-reactive composition may be mixed together by any known mixing process and equipment. The order in which the components are mixed to produce the isocyanate-reactive composition is not important; two or more compounds may be mixed together, followed by the addition of any other optional components. For example, in a preferred embodiment, the thixotropic additive compound (Bi) is first premixed with the isocyanate-reactive compound (Bii), followed by the addition of any optional compound (Biii) to form the B-side component.

[0077] In another broad embodiment, the process for producing the polyurethane or polyisocyanurate foam-forming reactive composition of the present invention generally comprises mixing (A) at least one isocyanate component as an A-side component, (B) at least one isocyanate-reactive component as a B-side component, and (C) optional components, as needed. Components (A) through (C) above are mixed together under process conditions such that the reactive components are thoroughly mixed together to form a homogeneous reactive polyurethane or polyisocyanurate foam-forming composition.

[0078] For example, in one preferred embodiment, a process for producing the polyurethane or polyisocyanurate reactive foam-forming composition of the present invention includes the following steps: (I) providing a reactor vessel or container for receiving the above-described components (A)-(C) to form a reaction mixture therein; (II) adding the above-described components (A)-(C) to the reactor vessel; (III) mixing the components (A)-(C) in the reactor vessel or container under process conditions to form a homogeneous reaction mixture; and (IV) reacting the above-described components (A)-(C) to form a polyurethane or polyisocyanurate foam.

[0079] The components that make up the foam-forming reactive composition may be mixed together by any known urethane foam mixing process and equipment. Typically, an impingent mixer is used to mix the A-side and B-side, as well as any additional optional components. The order in which the components are mixed to form the polyurethane or polyisocyanurate reactive foam-forming composition is not important; two or more compounds may be mixed together, followed by the addition of any other optional components. For example, in a typical embodiment, preparing the foam-forming composition includes providing at least one isocyanate component (A), such as one or more polyisocyanate compounds, as part of the A-side component of the foam-forming composition; providing at least one isocyanate-reactive component (B), such as one or more polyol compounds, as part of the B-side component of the foam-forming composition; and combining the at least one polyisocyanate compound (A-side), the at least one polyol compound (B-side), and any optional compounds, such as a blowing agent, catalyst, and / or surfactant, as component (C), to form the foam-forming composition.

[0080] In preparing the foam-forming composition, the A-side containing the polyisocyanate compound and the B-side containing the polyol compound can be prepared separately and individually and then mixed together in a foaming device such as a high-pressure impinging mixer. The A-side and / or B-side can include any of a number of optional ingredients, compounds, agents, components, or additives. In some embodiments, one or more of the other optional compounds (components) of the foam-forming composition, such as a blowing agent, surfactant, and / or catalyst, component (C), can be added to the foam-forming composition via (1) the polyisocyanate compound (A-side), (2) the polyol compound (B-side), or (3) both the A-side and the B-side. In other embodiments, the blowing agent, surfactant, and / or catalyst, component (C), can be added to the A-side and / or B-side before the A-side and the B-side are mixed together or at the same time as the A-side and the B-side are mixed together. For example, foaming additives as component (C), such as catalysts and surfactants, are sometimes premixed into the B-side before the premixed B-side ingredients are mixed with the A-side. Often, the blowing agent is premixed into the B-side as well. In other embodiments, the blowing agent is sometimes mixed online as a separate stream during the foaming process.

[0081] As previously mentioned, in one embodiment, the A-side and B-side of the foam-forming composition are prepared separately and individually from components (A) through (C). In a preferred embodiment, all of the components, ingredients, and optional components, if present, can be mixed together in the desired concentrations as an isocyanate component premix (A-side) and a polyol component premix (B-side) to prepare the final polyurethane or polyisocyanurate foam-forming composition.

[0082] In one general embodiment, the weight ratio of A-side (polyisocyanate side) to B-side (polyol side) forming the reactive foam-forming composition can generally be in the range of X:1 to Y:1, where X can be a value less than 1 and Y can range from 1 to 4. For example, in one preferred embodiment, the weight ratio of A-side to B-side is 0.25:1 to 4:1 by weight. With respect to the molar ratio of isocyanate groups (i.e., number of NCO groups) on the A-side to isocyanate-reactive groups (i.e., number of OH groups) on the B-side, the molar ratio can range from 1.1:1 to 6:1 in one embodiment, and from 1.5:1 to 5:1 in another embodiment.

[0083] The mixing of the ingredients may be carried out at a temperature of from 5°C to 80°C in one embodiment, from 10°C to 60°C in another embodiment, and / or from 15°C to 50°C in yet another embodiment.

[0084] The resulting foam-forming composition produced according to the above process is advantageously used to prepare rigid foams of the present invention, such as PUR foam, PIR foam, or a combination of both PIR and PUR foams. Conventional processes and equipment can be used to make rigid foams. In a typical embodiment, for example, the process of the present invention for producing polyurethane foam products includes the steps of (I) mixing an A-side component including at least one isocyanate compound, such as a polyisocyanate, and a B-side component including at least one isocyanate-reactive compound, such as a polyol compound, and any optional ingredients, as needed, to form a reactive foam-forming composition, and (II) once the components are mixed together, reacting the resulting mixture to form a polyurethane or polyisocyanurate foam. The reactive mixture is reacted to form a foam and then cured, and heat may be applied to the reaction mixture, if necessary, to accelerate the curing reaction. For example, the resulting reactive blend is then exposed to conditions sufficient to cause a foaming reaction and cure the reactive formulation to form a rigid foam. For example, the mixture of the A-side and B-side can be heated at an elevated temperature for a desired period of time to cure the foam-forming composition. The ingredients may be heated at a temperature of from 25°C to 80°C in one embodiment, from 35°C to 70°C in another embodiment, and / or from 45°C to 60°C in yet another embodiment.

[0085] Various methods can be used to manufacture insulation products incorporating rigid polyurethane or polyisocyanurate foam, including, for example, a continuous double-belt lamination process for making insulated metal panels with rigid metal facers (such as steel facers) on both the top and bottom of the panel; a continuous process for making boardstock foam with flexible facers, such as aluminum foil or paper, on both sides of the foam; a discontinuous process for making three-dimensionally shaped insulation panels or articles by injecting a reactive formulation into a mold cavity followed by subsequent curing of the formulation in the mold at temperatures ranging from 25°C to 80°C for a desired time; and other processes. Those skilled in the art can adjust the reaction rates of the current information to achieve the best mold filling and foam cure for the most economical production.

[0086] A process that can be used to manufacture insulating products can be the continuous double-belt lamination process described above. This process can include movable upper and lower belts, each having a heating element and a pressure mechanism that transfers heat and pressure to the product between the belts. One advantage of using a double-belt lamination process and apparatus can be that the product can be continuously held under heat for a desired period of time, and then cooled and set in place.

[0087] The isocyanate-reactive compositions of the present invention for making rigid polyurethane or polyisocyanurate foams may, in one typical embodiment, be applied at a density of 20 g / cm 3 ~60g / cm 3 In an exemplary embodiment, the rigid polyurethane or polyisocyanurate foam has a density of 25 g / cm3 in one embodiment. 3 ~60g / cm 3 and in another embodiment 30 g / cm 3 ~60g / cm 3 and in yet another embodiment 32 g / cm 3 ~50g / cm 3 and in yet another embodiment 35 g / cm 3 ~50g / cm 3 It could be.

[0088] The rigid polyurethane or polyisocyanurate foams of the present invention also exhibit several beneficial properties, such as (1) low thermal conductivity (improved thermal insulation performance) and (2) increased mechanical toughness. For example, the foams of the present invention exhibit low thermal conductivity at 10°C of 19.5 mW / mK in one general embodiment, 16.0 mW / mK to 19.5 mW / mK in another embodiment, 16.0 mW / mK to 19.2 mW / mK in yet another embodiment, 17.0 mW / mK to 19.2 mW / mK in yet another embodiment, and 17.0 mW / mK to 19.0 mW / mK in yet another embodiment. The insulating performance of the rigid foams of the present invention, as measured by thermal conductivity (or "K-factor"), is defined and determined by the procedure set forth in ASTM C518-04(2010).

[0089] Additionally, the foams of the present invention advantageously exhibit good mechanical toughness, as measured by the percentage of friability defined and determined by the procedure set forth in ATSM C421(2014). For example, in typical embodiments, the foams exhibit a rolling friability of 10% or less. In exemplary embodiments, the friability of rigid foams can range from 0.1% to 10%, 0.5% to 10%, and / or 1% to 10%.

[0090] The polyurethane foams produced by the process of the present invention can be used in a variety of applications and end uses, including, for example, insulation applications in the building and construction industry. Additionally, polyurethane foams can be used in coatings, adhesives, paper and packaging applications. Polyurethane foams can also be used in appliances, refrigerated shipping container applications, and the like. [Example]

[0091] The following examples are presented to further illustrate the invention, but should not be construed as limiting the scope of the claims. Unless otherwise indicated, all parts and percentages are by weight.

[0092] Various terms and designations are used in the Inventive Examples (Inv. Ex.) and Comparative Examples (Comp. Ex.), and these are explained below. "PUR" stands for rigid polyurethane in reference to the foam. "PIR" stands for rigid polyisocyanurate in relation to the foam. "DEG" stands for diethylene glycol. "PEG" stands for polyethylene glycol. "FR" stands for flame retardant.

[0093] The various ingredients, components, or raw materials used in the inventive examples (Inv. Ex.) and comparative examples (Comp. Ex.) are described below.

[0094] Six different types of polyols were used in the examples: (1) Polyol A is a polyester polyol prepared using an aromatic dicarboxylic acid and a polyglycol such as DEG, PEG200, or glycerol. (2) Polyol B is a polyester polyol similar to polyol A. (3) Polyol C is a polyester polyol similar to polyol A. (4) Polyol D is a polyether polyol manufactured by The Dow Chemical Company, such as VORATEC™ SD 301.

[0095] The characteristics of each of the six different types of polyols used in the examples are listed in Table I.

[0096] [Table 1] A variety of different types of foaming additives were used in the examples and such additives are listed in Table II.

[0097] [Table 2]

[0098] Polyisocyanates used in the examples include Polyisocyanate A=PAPI™ 580N, and Polyisocyanate B=PAPI™ 27, both available from The Dow Chemical Company.

[0099] The thixotropic additives used in the examples include thixotropic additive A, which is an MFC paste such as EXILVA™ P01V available from Borregaard, and thixotropic additive B, which is cellulose nanocrystals (CNC) available from CelluForce.

[0100] The physical blowing agent used in the examples and comparative examples is cyclopentane.

[0101] The foam-forming compositions presented in Tables III and IV are two exemplary systems of the present invention based on two different polyol packages: (1) 100% polyester polyol, and (2) a blend of polyester and polyether polyols from Tables III and IV, respectively. Thermal conductivity or K-factor is measured at two different temperatures: (1) 50°F (10°C) and (2) 20°F (-6.7°C), respectively. These two systems were used in the examples to determine the effective range of the thixotropic additive.

[0102] General procedure for preparing foams The polyol, surfactant, flame retardant, catalyst, and water were added to a plastic mixing cup, and the plastic cup with its contents was weighed. The contents of the cup were then mixed in a high-speed overhead mixer to prepare the "polyol package" (side B). The target amount of blowing agent was then added to the cup and thoroughly mixed with the polyol package. Subsequently, the desired amount of polyisocyanate compound, component A (side A), was added to the compound mixture in the cup. The resulting complete compound was immediately mixed in a high-speed overhead mixer at a mixer speed of 3,000 rpm for 5 seconds, and then the compounded compound was poured into a preheated mold preheated to 55°C. The mold size was 5 cm x 20 cm x 30 cm. The mold was positioned vertically along the length of the mold for forming. After approximately 20 minutes, the foam was removed from the mold and allowed to sit on a lab bench overnight before testing the physical properties of the resulting foam product.

[0103] Test Measurement The foam-forming compositions and foam products made according to the Examples and Comparative Examples described herein were subjected to various tests.

[0104] Viscosity measurement Viscosity measurements on polyols or polyol blends with and without thixotropic additives were performed using an ARES rheometer (TA Instrument) at a temperature of 60°C. A 50 mm cup and plate geometry was used for all rheological measurements. Sample thickness was held constant at approximately 1.5 mm. Dynamic viscosity data were collected from frequencies between 0.01 rad / s and 100 rad / s at a constant strain of 10%. The ratio of viscosities at 0.1 rad / s and 100 rad / s was calculated and reported; the higher the viscosity ratio, the more thixotropic the fluid exhibited.

[0105] Creaming and Gel Times Creaming time and gel time are determined according to the test procedures described in ASTM D7487(2013). The general procedure for measuring creaming time and gel time is as follows: Free rise foams are made by the plastic cup method described above in "General Procedure for Preparing Foams." Using this method, polyol, surfactant, flame retardant, catalyst, and water are weighed into a plastic cup. An overhead mixer is used to mix the polyol compound and other ingredients in isocyanate-reactive component B (side B). The appropriate amount of blowing agent is then added to the cup and thoroughly mixed into the isocyanate-reactive component (side B). The isocyanate component (side A) is then added to the cup, followed by immediate mixing for 5 seconds at approximately 3,000 rpm using an overhead mixer. The time recording begins when mixing of the isocyanate component with the isocyanate-reactive component mixture is triggered. When the foam-forming formulation in the cup shows a distinct color or appearance change based on the formation of numerous air bubbles (or more commonly known to those skilled in the art as creaming), that time is recorded as the "creaming time." The tip of a wooden tongue depressor is then dipped into the foam-forming formulation and quickly withdrawn to determine if the foaming mixture becomes stringy. The time at which the foaming formulation becomes stringy based on the wooden tongue depressor test is recorded as the "gel time."

[0106] Thermal conductivity (K factor or lambda value) Within 24 hours after the foams were made (and after they had rested overnight on the laboratory bench), foam square samples measuring 20 cm x 20 cm x 2.5 cm were cut from the interior and center of the foams. The thermal conductivity (K-factor) of each foam sample was measured at 50°F (10°C) for the PIR system (Table III) and at 20°F (-6.7°C) for the PUR system (Table IV) according to the procedure described in ASTM C518-04(2010). The accuracy of the K-factor measurements is typically within 0.1 mW / mK. The average of the K-factor measurements of at least two foam square samples tested was reported.

[0107] Foam Density The density of the rigid foam was measured according to the procedure described in ASTM 1622-03(2008). The rigid foam samples were cut into cubes measuring 5 cm x 5 cm x 5 cm. The samples were weighed to measure the exact dimensions of each sample. The density of the samples was then calculated.

[0108] Friability Foam crushability was measured by testing foam samples in a tumbling machine according to the procedure described in ASTM C421 (2014). The apparatus contained an oak cube box with interior dimensions of 7 1 / 2 inches x 7 3 / 4 inches x 7 3 / 4 inches (190 mm x 197 mm x 197 mm). The box shaft was motor-driven at a constant speed of 60 ± 2 rpm. Twenty-four 3 / 4 ± 1 / 32-inch (19 mm ± 0.8-mm) cubes of room-dried solid oak were placed in the box containing the test foam samples. Test foam samples were prepared by cutting molded foam into 1 ± 1 / 16-inch (25.4 ± 1.6-mm) cubes with a fine-tooth saw.

[0109] Open cell content The open cell content of rigid PU foam samples was measured according to ASTM D-6226. A Micromeretics AccuPyc 1330 pycnometer equipped with the FoamPyc option for calculating open cell content was used for this measurement. Five foam specimens with nominal dimensions of 1 inch x 1 inch x 1 inch (2.54 cm x 2.54 cm x 2.54 cm) taken from various points on the foam sample were measured. Any foam specimen with obvious defects upon visual inspection was excluded from testing. All foam specimens were conditioned for a minimum of 24 hours at ASTM standard laboratory conditions prior to measurement. The average open cell content for each foam specimen was reported.

[0110] Examples 1-7 and Comparative Examples A and B: Thixotropic Additives in PIR Systems Comparative Example A Following the "General Procedure for Preparing Foams" above, 180 g of foaming mixture was prepared and immediately poured into a vertically positioned mold measuring 5 cm x 20 cm x 30 cm. For this particular formulation, approximately 135 g of foaming mixture was poured into the mold interior. After 20 minutes, the resulting foam was removed from the mold and allowed to sit overnight on a lab bench before testing the resulting foam product for physical properties. The results of the foam property characterization are summarized in Table III.

[0111] Examples 1 to 3 A three-stage mixing procedure was used to pre-disperse 2 pts of thixotropic additive A into 73 pts of polyol A using a Flack Tek mixer, including: (1) adding 2 pts of thixotropic additive A to 8 pts of polyol A in a mixing cup, followed by mixing the resulting mixture in the Flack Tek mixer at 10,000 rpm for 1 minute; (2) adding an additional 20 pts of polyol A to the mixing cup, followed by mixing at 10,000 rpm for 1 minute; and (3) adding another 45 pts of polyol A to the mixing cup, followed by mixing at 10,000 rpm for 1 minute. The resulting thixotropic additive-polyol mixture was used to prepare foam-forming formulations using a protocol similar to that used in Comparative Example A and by following the detailed formulation data set forth in Table III. Foam properties for Inventive Examples 1-3 are summarized in Table III.

[0112] Examples 4 and 5 The protocol for dispersing thixotropic additive A in polyol A and subsequent foam preparation was replicated as described in Examples 1-3 above, except that only 1 pts of thixotropic additive A was used. Foam properties for inventive examples 4 and 5 are reported in Table III.

[0113] Example 6 The protocol for dispersing thixotropic additive A in polyol A and subsequent foam preparation was replicated as described in Examples 1-3 above, except that only 0.5 pts of thixotropic additive A was used. Foam properties for inventive example 6 are reported in Table III.

[0114] Example 7 Thixotropic Additive B was added directly to a mixture of Polyol A and Polyol B according to the formulation set forth in Table III, followed by vigorously mixing in a high shear overhead mixer. The other foaming ingredients shown in Example 7 were then added to the Polyol A and B mixture containing Thixotropic Additive B and thoroughly mixed to produce a foam. The foam of Example 7 was prepared using the same protocol as described in Examples 1-3. The foam properties of the foam of Example 7 are reported in Table III.

[0115] Comparative Example B The protocol for dispersing thixotropic additive A into polyol A and subsequent foam preparation is replicated as described in Examples 1-3 above, except that 5 pts of thixotropic additive A is used. The foam properties of the foam of Comparative Example B are reported in Table III.

[0116] [Table 3] Notes for Table III: * "nm" stands for "not measured" as large samples are required for this measurement.

[0117] The results in Table III show that the thermal conductivity (or K-factor) of foams made according to the inventive examples is lower than that of the comparative examples. The incorporation of MFC into rigid PIR foam also appears to reduce the physical crushability of the foam. This unexpected increase in toughness of the foam may be due to the three-dimensional network similar to the morphology of the MFC incorporated into the foam. Furthermore, the thixotropic additive may have a beneficial effect of stabilizing cell formation.

[0118] Comparative Example C and Examples 8 and 9: Thixotropic Additives in PUR Systems Comparative Example C The polyols and additives used in this Comparative Example C and in the foam preparation are listed in Table 4. The foam property results are also summarized in Table 4.

[0119] Example 8 In this Example 8, 2 pts of Thixotropic Additive A was pre-dispersed in 18 pts of Polyol A using a Flack Tek mixer in a two-stage mixing procedure: (1) adding 2 pts of thixotropic additive A to 8 pts of polyol F in a mixing cup, followed by mixing the resulting mixture in a Flack Tek mixer at 10,000 rpm for 1 minute; (2) adding an additional 10 pts of Polyol A to the mixing cup, followed by mixing at 10,000 rpm for 1 minute. The resulting thixotropic additive A-polyol A mixture was used to prepare a foam formulation by following the detailed formulation data set forth in Table IV. The foam properties of Inventive Example 8 are summarized in Table IV.

[0120] Example 9 In this Inventive Example 9, the procedure of Inventive Example 8 set forth in Table IV for making foam samples is replicated for testing, except that only 1 pts of Thixotropic Additive A is used. The foam properties of Inventive Example 9 are set forth in Table IV.

[0121] [Table 4]

[0122] The results reported in Table IV show that the incorporation of a thixotropic additive is beneficial for improving foam properties such as K-factor when a mixture of polyols with high and low OH functionality is used, unless the mixture of polyols already exhibits strong shear thinning behavior.

[0123] The polyols used in the examples set forth in Tables III and IV are polyester polyols and blends of polyester polyols and polyether polyols. When comparing the data for the different foaming systems within each individual Table III and IV, it can be concluded that the thixotropic additive is effective in both foaming systems as long as the average hydroxyl functionality of all polyols combined in the isocyanate-reactive composition is 3.0 or less. The present invention includes the following aspects. [1] 1. An isocyanate-reactive composition comprising: (i) at least one isocyanate-reactive compound; (ii) a predetermined amount of at least one thixotropic modifier, wherein the flow characteristics of the at least one thixotropic modifier are such that the isocyanate-reactive composition has a shear thinning behavior characterized by a ratio of the viscosity of the isocyanate-reactive composition measured at 60°C to a shear rate of 0.1 rad / sec and 100 rad / sec that is between 10 and 300. [2] 1. The composition of claim 1, wherein the at least one thixotropy modifier is microfibrillated cellulose, nanocellulose, cellulose ether, starch, associative polymer, or a mixture thereof. [3] The composition according to [1], wherein the amount of the at least one thixotropic modifier is 0.01 parts by weight to 5 parts by weight, based on the total weight of all isocyanate-reactive compounds in the isocyanate-reactive composition, component (B), in 100 parts by weight. [4] 1. The composition of claim 1, wherein the at least one isocyanate-reactive compound is selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, and mixtures thereof. [5] [1] The composition of [1], wherein the at least one isocyanate-reactive compound comprises one or more polyol compounds, and the total average hydroxyl functionality of all of the polyols combined present in the isocyanate-reactive composition is less than 3. [6] The composition of [1], wherein the at least one isocyanate-reactive compound comprises one or more polyol compounds, and the total average hydroxyl functionality of all of the polyols combined present in the isocyanate-reactive composition is 1.8 to 2.7. [7] 1. A foam-forming composition for producing polyurethane or polyisocyanurate foam, comprising: (A) at least one isocyanate component; (B) at least one isocyanate-reactive component, wherein the at least one isocyanate-reactive component is the isocyanate-reactive composition described in [1]. [8] 8. The foam-forming composition of [7], further comprising a surfactant, a catalyst, a physical blowing agent, a chemical blowing agent, a flame retardant additive, a nucleating agent, or a mixture thereof. [9] [7] The composition according to [7], wherein the at least one isocyanate component, component (A), is at least one aromatic isocyanate compound, or the at least one isocyanate component, component (A), is a blend of (1) at least one aromatic isocyanate compound and (2) at least one aliphatic isocyanate compound.

[10] 1. A process for producing a foam-forming composition for producing polyurethane or polyisocyanurate foam, comprising: (A) at least one isocyanate component; (B) at least one isocyanate-reactive component, wherein the at least one isocyanate-reactive component is the isocyanate-reactive composition described in [1].

Claims

1. 1. An isocyanate-reactive composition comprising: (i) at least one isocyanate-reactive compound; (ii) a predetermined amount of at least one thixotropy modifier; the at least one isocyanate-reactive compound is one or more polyol compounds, the polyol compounds comprising one or more polyester polyol compounds, and the total average hydroxyl functionality of all of the polyol compounds combined present in the isocyanate-reactive composition is less than 3; the polyester polyol compound is 30 parts by weight or greater, based on the total weight of all isocyanate-reactive compounds in 100 parts by weight of the isocyanate-reactive composition; the at least one thixotropy modifier is microfibrillated cellulose, nanocellulose, or a mixture thereof; the amount of the at least one thixotropy modifier is 0.01 parts by weight to 5 parts by weight, based on the total weight of all isocyanate-reactive compounds in 100 parts by weight in the isocyanate-reactive composition; an isocyanate-reactive composition, wherein the flow properties of said at least one thixotropic modifier are such that said isocyanate-reactive composition has shear thinning behavior characterized by a ratio of the viscosities of said isocyanate-reactive composition measured at 60°C, 0.1 rad / sec and 100 rad / sec shear rates of between 10 and 300.

2. 10. The composition of claim 1, wherein the at least one isocyanate-reactive compound further comprises a polyol compound selected from the group consisting of polyether polyols, polycarbonate polyols, and mixtures thereof.

3. 10. The composition of claim 1, wherein the polyester polyol compound is 60 parts by weight or greater, based on the total weight of all isocyanate-reactive compounds in 100 parts by weight in the isocyanate-reactive composition.

4. 1. A foam-forming composition for producing polyurethane or polyisocyanurate foam, comprising: (A) at least one isocyanate component; (B) at least one isocyanate-reactive component, wherein the at least one isocyanate-reactive component is the isocyanate-reactive composition of claim 1.

5. 5. The foam-forming composition of claim 4, further comprising a surfactant, a catalyst, a physical blowing agent, a chemical blowing agent, a flame retardant additive, a nucleating agent, or a mixture thereof.

6. 5. The composition of claim 4, wherein the at least one isocyanate component, component (A), is at least one aromatic isocyanate compound, or the at least one isocyanate component, component (A), is a blend of (1) at least one aromatic isocyanate compound and (2) at least one aliphatic isocyanate compound.

7. 1. A process for producing a foam-forming composition for producing polyurethane or polyisocyanurate foam, comprising: (A) at least one isocyanate component; (B) at least one isocyanate-reactive component, wherein the at least one isocyanate-reactive component is the isocyanate-reactive composition of claim 1.

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