Preparation of Polyurethane and Polyisocyanurate Foams Using Liquid Siloxane Nucleating Additives

Abstract

The present invention discloses a method for preparing polyisocyanurate and polyurethane foams by using a liquid silicone nucleating additive, and a foam-forming composition for preparing foams having improved thermal insulation properties, the foam-forming composition comprising an isocyanate component, an isocyanate-reactive component, a blowing agent, and a liquid silicone nucleating additive.

Description

Technical Field

[0001] The present disclosure relates to the use of liquid siloxane nucleating additives in the preparation of thermal insulation foams. More specifically, the present disclosure relates to foam-forming compositions comprising at least one liquid siloxane material as a nucleating additive, and methods for preparing rigid polyisocyanurate (PIR) and polyurethane (PUR) foams that exhibit excellent thermal insulation properties and good mechanical characteristics.

[0002] Preface

[0003] Rigid polyisocyanurate (PIR) and polyurethane (PUR) foams have excellent thermal insulation properties and can thus be used in various applications such as construction and building, roofing, tanks, pipes, appliances, refrigerated transportation, etc. The reason for these unique features is the combination of a closed-cell honeycomb structure containing specific gases such as hydrocarbons with low thermal conductivity. With the market demand for better thermal insulation and government regulations for increasingly higher energy efficiency, there is an urgent need and a continuous market demand for further improving the thermal insulation properties of PIR / PUR rigid foams. One such solution is to obtain foams with a finer honeycomb structure to achieve a lower thermal conductivity (also known as the λδ value or K-factor). There is still a need to achieve better thermal insulation while maintaining ease of processing, light weight, and good mechanical characteristics. Summary of the Invention

[0004] The object of the present disclosure is to provide compositions for preparing rigid polyisocyanurate (PIR) and polyurethane (PUR) foams, methods for preparing PIR and PUR foams, and blowing agent compositions comprising novel liquid siloxane additives for preparing PIR and PUR foams, and foams prepared therefrom.

[0005] The present disclosure is based on the following surprising discovery: Although liquid siloxane additives are insoluble in typical polyols and polyisocyanates used to prepare PIR or PUR foams, they can be used as additives in foam preparation to reduce the K-factor of the resulting rigid PIR / PUR foams when incorporated in small amounts during the foam preparation process.

[0006] A first embodiment of the preparation method is to provide a foam-forming composition comprising: an isocyanate-reactive component comprising at least one or more polyols; a polyisocyanate component; a blowing agent; and at least one liquid siloxane nucleating additive in an amount of 0.1 pts to 5 pts based on the total weight of at least one or more polyols in 100 pts of the isocyanate-reactive component; wherein at least one liquid siloxane additive has the following structure:

[0007]

[0008] wherein R1 can be a C1-C4 alkyl group or a trimethylsilyloxy group, and R2 can be a C5 to C18 alkyl group, a C5 to C18 cycloalkyl group, or a C7 to C18 aralkyl group.

[0009] Any auxiliary components such as blowing catalysts, gel catalysts, trimerization catalysts, surfactants, reactive or non-reactive diluents, additional physical or chemical blowing agents, antioxidants, flame retardant additives, pigments, fillers, etc. can be incorporated into the isocyanate-reactive component or into the isocyanate component first before mixing the isocyanate-reactive component, the isocyanate component, the blowing agent, and at least one liquid silicone nucleating additive together for foam preparation, or can be mixed into the foam-forming composition as a separate stream during the mixing of the isocyanate-reactive component and the isocyanate component. Not all of these auxiliary components are necessary for foam preparation and should not be construed as limiting the scope of the present disclosure in any way.

[0010] Another embodiment of the present invention is to provide a blowing agent composition comprising at least one blowing agent and at least one liquid silicone nucleating additive, wherein the blowing agent is selected from the group consisting of aliphatic hydrocarbons having 3 to 7 carbon atoms, cycloaliphatic hydrocarbons having 3 to 7 carbon atoms, and hydrofluoroolefins, or mixtures thereof, and wherein the at least one liquid silicone nucleating additive has a chemical structure of Formula I and the viscosity of the silicone nucleating additive at room temperature (25 °C) is not greater than 10 centistokes (cSt).

[0011] Another embodiment of the present invention is to provide a method for preparing rigid polyisocyanurate (PIR) and / or polyurethane (PUR) foams using the above foam-forming composition, wherein the polyisocyanurate and polyurethane foams are prepared by reacting at least one isocyanate-reactive component with at least one polyisocyanate component in the presence of a blowing agent and at least one liquid silicone nucleating additive, wherein the at least one liquid silicone nucleating additive can be premixed into the blowing agent at a molar ratio between 1:100 and 1:10 or can be mixed into the foam-forming composition as a separate stream. Additionally, the isocyanate index of the formed foam is between 100 and 600. The isocyanate index is defined as the stoichiometric ratio of the isocyanate groups in the isocyanate component to the hydroxyl groups in the isocyanate-reactive component (e.g., polyol, water, etc.) multiplied by 100.

[0012] Any optional auxiliary components such as blowing catalysts, gel catalysts, trimerization catalysts, surfactants, reactive or non-reactive diluents, additional physical or chemical blowing agents, antioxidants, flame retardant additives, pigments, fillers, etc. can be incorporated into the isocyanate-reactive component or into the isocyanate component first before mixing the isocyanate-reactive component, the isocyanate component, the blowing agent, and at least one liquid silicone additive together for foam preparation, or can be mixed into the foam-forming composition as a separate stream during the mixing of the isocyanate-reactive component and the isocyanate component. Not all of these auxiliary components are necessary for foam preparation and should not be construed as limiting the scope of the present disclosure in any way.

[0013] The foam density can be in the range of 20 kg / m 3 –200 kg / m 3 (e.g., 25–100 kg / m 3 、or 25–60 kg / m 3 ). In this embodiment, the thermal conductivity of the formed foam can be no greater than 20.6 mW / m-K at 10 °C. In this embodiment, the compressive strength of the formed foam can be no less than 100 KPa (e.g., at least 120 KPa).

[0014] It should be noted that throughout the present disclosure, at least one liquid silicone nucleating additive is sometimes referred to as an additive and sometimes as a material. The silicone can be incorporated directly into the foam-forming composition as a separate stream or added by premixing with the blowing agent or any optional auxiliary additive used for foam preparation.

[0015] It is to be understood that the foregoing general description and the following detailed description are both exemplary and explanatory only and are not restrictive of the claims. Detailed Description

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this method belongs. In addition, all publications, patent applications, patents, and other references mentioned herein are incorporated by reference. As disclosed herein, the terms "composition", "formulation", or "mixture" refer to a physical blend of different components, which is obtained by simply physically mixing the different components. As disclosed herein, "and / or" means "and, or as an alternative". Unless otherwise specified, all ranges include the end values.

[0017] In various embodiments, compositions are provided for preparing rigid polyisocyanurate (PIR) and polyurethane (PUR) foams, which comprise a polyisocyanate component having two or more isocyanate groups in each molecule, an isocyanate-reactive component comprising one or more polyols reactive with the isocyanate groups, a blowing agent, and at least one liquid silicone nucleating additive. Without being bound by theory, generally the polyisocyanate component and the isocyanate-reactive component are stored in separate containers until they are blended together and a polymerization reaction occurs between the isocyanate groups and the hydroxyl groups to form polyisocyanurate and polyurethane. Polyurethane refers to a polymer comprising a main chain formed of repeating units (-NH-C(O)-O-) derived from the reaction between isocyanate groups and hydroxyl groups, while polyisocyanurate comprises a polyisocyanurate ring structure formed by the trimerization of isocyanate groups.

[0018] As used herein, the terms "polyisocyanurate and polyurethane", "polyisocyanurate or polyurethane", "PIR and PUR", "PIR or PUR", and "PIR / PUR" are used interchangeably and refer to a polymeric system comprising both polyurethane chains and polyisocyanurate groups, the relative proportions of which depend substantially on the stoichiometric ratio of the polyisocyanate compound and the polyol compound contained in the raw materials. In addition, the composition of ingredients such as catalysts and other additives, as well as processing conditions such as temperature, reaction duration, etc., can also slightly affect the relative amounts of PUR and PIR in the final foam product. Thus, the polyisocyanurate and polyurethane foams (PIR / PUR foams) as described in the context of the present disclosure refer to foams obtained as a reaction product of the above polyisocyanates with compounds having isocyanate-reactive groups, particularly polyols. In addition, additional functional groups, such as urethane, biuret, or urea, can be formed during the reaction. The PIR / PUR foam can be a rigid foam. The compositions of the present disclosure can additionally comprise catalysts, blowing agents, and other additives.

[0019] According to a broad embodiment of the present disclosure, a foam-forming composition and a method for preparing rigid polyurethane and polyisocyanurate foams for the foam-forming composition comprise four components, namely an isocyanate component (Component A) comprising at least one polyisocyanate compound, an isocyanate-reactive component (Component B) comprising at least one or more polyols, at least one blowing agent (Component C), and at least one liquid silicone nucleating additive (Component D), wherein the at least one liquid silicone nucleating additive can be premixed with the blowing agent or incorporated as a separate stream during foam preparation. Additionally, other optional auxiliary components such as surfactants, catalysts, additional blowing agents, flame retardant additives, etc. can be premixed into the isocyanate-reactive component or the isocyanate component and then mixed with the other components to prepare PUR / PIR foams or mixed as separate streams into the foam-forming composition for foam preparation. Not all of these optional auxiliary components are necessary for foam preparation and should not be construed as limiting the scope of the present disclosure in any way.

[0020] Various embodiments of the compositions disclosed herein can vary in terms of the amounts, contents, or concentrations of the isocyanate-reactive component and the isocyanate component. The isocyanate component in these embodiments is calculated based on the total weight of the foam-forming composition, which is the combined weight of the isocyanate-reactive component, the isocyanate component, the blowing agent, at least one liquid silicone nucleating additive, and all optional auxiliary components (if not already incorporated into one of the four components (A), (B), (C), or (D)); while the contents of other components such as the at least one liquid silicone nucleating additive, surfactants, catalysts, blowing agents, and other additives are based on the total polyol weight equal to 100 parts (pts) in the isocyanate-reactive component.

[0021] I. Liquid Siloxane Nucleating Additives

[0022] Silicones are functional materials in organosilicon chemistry, characterized by Si–O–Si bonds. Typical linear and unbranched silicones can be represented by Structure A below, where the main chain consisting of repeating units of -(Si(CH3)2-O)- is capped at each end with tris(methyl)siloxy groups, and p is an integer, for example, from 1 to 100, so that the unbranched silicone molecule contains only two tris(methyl)siloxy groups.

[0023]

[0024] Branched silicones have more than two tris(methyl)siloxy groups. An example of a branched silicone is shown by the following formula, which contains four tris(methyl)siloxy groups:

[0025]

[0026] Siloxane materials are hydrophobic by nature. Unless the siloxane molecules are chemically modified additionally, they are insoluble in most common polyols used to prepare polyisocyanurate / polyurethane foams.

[0027] Surprisingly, it has been found that low molecular weight (Mw) liquid siloxanes having at least one long alkyl chain with 5 carbons and a longer length can be used as nucleating additives for preparing polyurethane and polyisocyanurate foams, resulting in foams with smaller cell sizes and improved thermal insulation properties. While not wishing to be bound by any theory, it is believed that the above liquid siloxane additives can provide nucleation centers when finely dispersed throughout the foam-forming composition, at which nucleation centers the blowing agent is converted into the gas phase and the density of bubble nucleation during the reactive foaming process is increased.

[0028] Specifically, the siloxanes useful in the present disclosure have a structure represented by Formula 1:

[0029]

[0030] wherein R1 can be a C1-C4 alkyl group or a trimethylsiloxy group, and R2 can be a C5 to C18 alkyl group, a C5 to C18 cycloalkyl group, or a C7 to C18 aralkyl group.

[0031] The liquid siloxane nucleating additive of the present invention advantageously used has a molecular weight of from 280 g / mol to 750 g / mol, including all individual values and subranges from 350 g / mol to 750 g / mol; for example, the liquid siloxane nucleating additive can have a number average molecular weight from a lower limit of 280 g / mol, 290 g / mol, 300 g / mol, or 320 g / mol to an upper limit of 750 g / mol, 700 g / mol, 650 g / mol, 600 g / mol, 550 g / mol, 525 g / mol, or 500 g / mol.

[0032] According to one embodiment of the present disclosure, the kinematic viscosity of the liquid siloxane nucleating additive at room temperature (i.e., at about 25 °C) is between 0.5 cSt and 10.0 cSt (mm 2 / s), preferably in the range of 1 cSt to 7.5 cSt, and more preferably in the range of 1.0 cSt to 5.0 cSt. Liquid siloxane additives with viscosities higher than 10.0 cSt are less effective in nucleating bubbles due to their slower diffusion, while liquid siloxane additives with viscosities lower than 0.5 cSt tend to show phase separation and reduced foaming stability during foam preparation.

[0033] Representative examples of liquid silicone nucleating additives suitable for the foam-forming compositions and foam preparation methods of the present invention include the following compounds SID4627.6, SIO6711.5, and SIO6715.7, all of which are commercially available from Gelest, Inc. (Morrisville, PA).

[0034]

[0035] According to one embodiment of the present disclosure, the liquid silicone nucleating additive can be mixed with other foaming components as a separate stream before foam preparation. Alternatively, the liquid silicone nucleating additive of the present invention can be premixed with at least one foaming agent of the foam-forming composition and then introduced to mix with all the foaming components used for foam preparation. In one embodiment of the present disclosure, based on the total weight of at least one or more polyols equal to 100 pts in the foam-forming composition, the amount of the liquid silicone nucleating additive is 0.1 pts to 5 pts (e.g., 0.2 pts to 3 pts, or 0.5 pts to 2.5 pts).

[0036] II. Blowing Agents

[0037] The liquid silicone nucleating additive of the present invention can be combined with various foaming agents used in the foam-forming composition to prepare rigid polyurethane and polyisocyanurate foams, including liquid or gaseous foaming agents that are evaporated to foam the polymer or gaseous foaming agents that are generated in-situ to foam the polymer.

[0038] A variety of conventional foaming agents can be used. For example, the foaming agent can be one or more of the following: water, various hydrocarbons, various hydrofluorocarbons, various hydrofluoroolefins, formic acid, inert gases, various chemical foaming agents that produce nitrogen or carbon dioxide under foaming reaction conditions, etc.; and mixtures thereof.

[0039] The blowing agents used in the present invention should have a boiling point of about -30°C to about 100°C at atmospheric pressure, preferably about -20°C to about 80°C, more preferably about 0°C to about 80°C, even more preferably about 5°C to about 75°C, and most preferably about 10°C to about 70°C. Exemplary examples of blowing agents that can be used in the present invention include low-boiling hydrocarbons such as heptane, hexane, n-pentane and isopentane, n-pentane and isopentane, and industrial-grade mixtures of n-butane and isobutane with propane; cycloalkanes such as cyclopentane and / or cyclohexane; low-boiling ethers such as furan, dimethyl ether and diethyl ether; low-boiling ketones such as acetone and methyl ethyl ketone; alkyl carboxylates such as methyl formate, dimethyl oxalate and vinyl lactate; various hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs) such as 1,1-dichloro-2,2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane, pentafluoropropane, heptafluoropropane, hexafluorobutene, (E,Z)1,1,1,4,4,4-hexafluoro-2-butene and trans-1-chloro-,3,3,3-trifluoropropene, trans-1,3,3,3-tetrafluoroprop-1-ene, 1,3,3,3-tetrafluoropropene, etc. Some of these blowing agents are commercially available materials called LBA, GBA, Opteon TM 1100, Opteon TM 1150, etc. Mixtures of these low-boiling liquids with each other and / or with other substituted or unsubstituted hydrocarbons can also be used.

[0040] Particularly advantageous blowing agents for the present invention are completely miscible with the liquid silicone nucleating additives as described in the previous section. At least one blowing agent of the present invention is selected from the group consisting of aliphatic hydrocarbons having 3 to 7 carbon atoms, cycloaliphatic hydrocarbons having 3 to 7 carbon atoms, and hydrofluoroolefins or mixtures thereof.

[0041] In various embodiments, the blowing agent can be selected at least in part based on the desired density of the final foam. The blowing agent can be added to the polyol side before the isocyanate-reactive component is combined with the isocyanate component, or added as a separate stream. Based on the total polyol amount of 100 pts in the foam-forming composition, the amount of the blowing agent is about 0.1 pts to about 40 pts (e.g., about 0.5 pts to about 35 pts, 1 pts to 30 pts, or 5 pts to 25 pts).

[0042] In a preferred embodiment, the foam-forming composition of the present invention comprises at least one liquid silicone nucleating additive and a blowing agent in a predetermined ratio. The molar ratio of the at least one liquid silicone nucleating additive to the blowing agent is generally from about 1:100 to 1:10, preferably from about 1:75 to 1:15, more preferably from about 1:50 to 1:15. In some embodiments, a higher proportion of the silicone nucleating additive can be used (e.g., at a molar ratio of about 1:9), but care must be taken to ensure that a large amount of the silicone additive does not cause any foaming stability problems. Conversely, a smaller proportion of the nucleating agent can also be used (e.g., a molar ratio of 1:125 or even 1:150), but when the level of the silicone nucleating additive used is too low, the improvement of the foam properties may be limited.

[0043] III. Isocyanate Component

[0044] In various embodiments, the isocyanate component of the foam-forming composition of the present invention may comprise, for example, one or more isocyanate compounds, including, for example, polyisocyanates. As used herein, "polyisocyanate" refers to a molecule having an average of greater than 1.0 isocyanate (NCO) groups / molecule, e.g., an average NCO functionality greater than 1.0.

[0045] The isocyanate compounds that can be used in the present invention can be aliphatic polyisocyanates, cycloaliphatic polyisocyanates, araliphatic polyisocyanates, aromatic polyisocyanates, or combinations thereof. Examples of isocyanates that can be used in the present invention include, but are not limited to, polymethylene polyphenyl isocyanate; toluene 2,4- / 2,6-diisocyanate (TDI); methylene diphenyl 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 (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-diisocyanato-2-methylcyclohexane; and combinations thereof, etc. In addition to the above isocyanates, partially modified polyisocyanates, including uretdione, isocyanurate, carbodiimide,

[0046] Uretonimine, urethane or biuret structures and their combinations, etc. can be used in the present invention.

[0047] The isocyanate compound can be polymeric. As used herein, when describing isocyanates, "polymeric" refers to homologues and / or isomers having a high molecular weight. For example, polymeric methylene diphenyl diisocyanate refers to the high molecular weight homologues and / or isomers of methylene diphenyl diisocyanate.

[0048] The isocyanate compound that can be used in the present invention can be a modified polyfunctional isocyanate, that is, a product obtained by the chemical reaction of an isocyanate compound. Exemplary are polyisocyanates containing esters, ureas, biurets, urethanes and carbodiimides and / or uretonimines. It is also possible to use a liquid polyisocyanate containing a carbodiimide group, a uretonimine group and / or an isocyanurate ring and having an isocyanate group (NCO) content of 10% by weight to 35% by weight, 10% by weight to 32% by weight, 10% by weight to 30% by weight, 15% by weight to 30% by weight or 15% by weight to 28% by weight. These include, for example, polyisocyanates based on 4,4'-, 2,4'- and / or 2,2'-diphenylmethane diisocyanate and the corresponding isomer mixtures, 2,4- and / or 2,6-toluene diisocyanate and the corresponding isomer mixtures; mixtures of diphenylmethane diisocyanate and PMDI; and mixtures of toluene diisocyanate and PMDI and / or diphenylmethane diisocyanate.

[0049] Alternatively or in addition, the isocyanate component may also contain an isocyanate prepolymer. Isocyanate prepolymers are known in the art; and are generally prepared by reacting (1) at least one isocyanate compound and (2) at least one polyol compound. The isocyanate prepolymer can be obtained by reacting the above monomeric isocyanate compound or polymeric isocyanate with one or more isocyanate-reactive compounds such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,4-butynediol, 1,5-pentanediol, neopentyl glycol, bis(hydroxymethyl)cyclohexane such as 1,4-bis(hydroxymethyl)cyclohexane, 2-methylpropane-1,3-diol, methylpentanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol and polybutylene glycol.

[0050] Prepolymers suitable for use as the polyisocyanate component are prepolymers having an NCO group content of from 5% to 30% by weight, or preferably from 10% to 30% by weight. These prepolymers can be prepared by the reaction of diisocyanates and / or polyisocyanates with materials comprising lower molecular weight diols and triols. Individual examples are aromatic polyisocyanates containing urethane groups, having an NCO content of from 5% to 30% by weight (e.g., from 10% to 30% by weight or from 15% to 30% by weight), which are obtained by the reaction of diisocyanates and / or polyisocyanates with, for example, lower molecular weight diols, triols, alkylene oxide diols, alkylene dioxide diols or polyalkylene oxide diols having a molecular weight of up to about 1000. These polyols can be used alone or in the form of a mixture of alkylene dioxide diols and / or polyalkylene oxide diols. By way of example, diethylene glycol, dipropylene glycol, polyethylene glycol, ethylene glycol, propylene glycol, butylene glycol, polypropylene glycol and polypropylene-polyethylene glycol can be used. Polyester polyols can also be used, as well as alkane diols such as butylene glycol. Other diols which are also useful include bis(hydroxyethyl)- or bis(hydroxypropyl)-bisphenol A, cyclohexanedimethanol and bis(hydroxyethyl)hydroquinone.

[0051] As described above, 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 from 1.75 to 3.50. All individual values and subranges including from 1.75 to 3.50 are included; for example, the isocyanate can have an average functionality with a lower limit of 1.5, 1.75, 1.85 or 1.95 to an upper limit of 3.5, 3.4, 3.3, 3.2, 3.1 or 3.

[0052] The isocyanate can have an isocyanate equivalent weight of from 80 g / eq to 300 g / eq. All individual values and subranges including from 80 g / eq to 300 g / eq are included; for example, the isocyanate can have an isocyanate equivalent weight with a lower limit 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.

[0053] The isocyanates used in the present invention can be prepared by known methods. For example, polyisocyanates can be prepared by the phosgenation of the corresponding polyamines, where polycarbamyl chlorides are formed and pyrolyzed to give the polyisocyanate and hydrogen chloride; or in another embodiment, polyisocyanates can be prepared by a phosgene-free process, such as by reacting the corresponding polyamine with urea and an alcohol to give a polyurethane and thermally decomposing it to give, for example, a polyisocyanate and an alcohol.

[0054] The isocyanates used in the present invention are commercially available. Examples of commercial isocyanates which can be used in the present invention include, but are not limited to, those sold under the trade name VORANATE TM 、PAPI TMand ISONATE TM such as VORANATE TM M 220 and PAPI TM polyisocyanates such as 27, all of which are purchased from Dow, Inc., and other commercial isocyanates.

[0055] Generally speaking, the amount of the isocyanate component can vary based on the end use of the rigid PIR / PUR foam. For example, as an illustrative embodiment, based on the total weight of all components in the foam-forming composition used to prepare the rigid PIR / PUR foam, the concentration of the isocyanate component can be about 20 wt% to about 80 wt%, or about 25 wt% to about 80 wt%, or about 30 wt% to about 75 wt%. The stoichiometric ratio of the isocyanate groups in the isocyanate component to the hydroxyl groups in the isocyanate-reactive component is between about 1.0 and 6, resulting in the formed polyurethane and polyisocyanurate foams having an isocyanate index between 100 and 600. The isocyanate index can have a lower limit of 100, 105, 110, 115, 120, 125, 150, 175, and 180 to an upper limit of 600, 575, 550, 525, 500, 475, 450, 425, 400, 375, 350, 325, and 300.

[0056] IV. Isocyanate-Reactive Components

[0057] In various embodiments of the present disclosure, the isocyanate-reactive component comprises one or more isocyanate-reactive compounds, such as polyols selected from the group consisting of: aliphatic polyols containing at least two hydroxyl groups, cycloaliphatic or aromatic polyols containing at least two hydroxyl groups, araliphatic polyols containing at least two hydroxyl groups, polyether polyols, polycarbonate polyols, polyester polyols, polyester ether polyols, and mixtures thereof. In one example, the polyols are selected from the group consisting of: C2-C16 aliphatic polyols containing at least two hydroxyl groups, C6-C15 cycloaliphatic or aromatic polyols containing at least two hydroxyl groups, C7-C15 araliphatic polyols containing at least two hydroxyl groups, and combinations thereof. The polyester polyols generally have an average molecular weight of 200 to 5,000. The polyether polyols have an average molecular weight of 100 to 5,000,

[0058] In one embodiment, the isocyanate-reactive component comprises a mixture of two or more different polyols, such as a mixture of two or more polyether polyols, a mixture of two or more polyester polyols, or a mixture of at least one polyether polyol and at least one polyester polyol. The isocyanate-reactive component has a functionality of at least 1.8 (the average number of isocyanate-reactive groups, particularly hydroxyl groups, in the polyol molecule) and an OH value of from 80 mg KOH / g to 2,000 mg KOH / g. The OH value of the isocyanate-reactive component is preferably from 100 mg KOH / g to 1,500 mg KOH / g, more preferably from 120 mg KOH / g to 1,000 mg KOH / g, even more preferably from 150 mg KOH / g to 750 mg KOH / g, still even more preferably from 150 mg KOH / g to 750 mg KOH / g, and yet even more preferably from 150 mg KOH / g to 500 mg KOH / g.

[0059] Generally, the average hydroxyl functionality of polyol compounds useful in the present invention, such as those described above, can range from as low as 1.8 to as high as 7.5. For example, an aromatic polyester polyol can have an average hydroxyl functionality of from 1.8 to 3.0; and a sucrose / glycerol-initiated polyether polyol can have an average hydroxyl functionality of from 3.0 to 7.5. Thus, the average hydroxyl functionality of the polyol compounds useful in the present invention can range from 1.8 to 7.5. All individual values and subranges from 1.8 to 7.5 are included; for example, the polyol compound can have an average hydroxyl functionality with a lower limit of from 1.8, 2.0, 2.2, 2.5, 2.7, 3.0 or 3.5 to an upper limit of from 7.5, 7.0, 6.5, 6.0, 5.7, 5.5, 5.2, 5.0, 4.8, 4.5, 4.2 or 4.0.

[0060] Generally, the polyol compound can have an average hydroxyl value in the range of from 75 mg KOH / g to 650 mg KOH / g. All individual values and subranges from 75 mg KOH / g to 650 mg KOH / g are included; for example, the polyol compound can have an average hydroxyl value with a lower limit of from 75 mgKOH / g, 80 mg KOH / g, 100 mg KOH / g, 125 mg KOH / g, 150 mg KOH / g or 175 mg KOH / g to an upper limit of from 650 mg KOH / g, 600 mg KOH / g, 550 mg KOH / g, 500 mg KOH / g, 450 mg KOH / g or 400 mg KOH / g.

[0061] Typically, the polyol compound may have a number average molecular weight of from 100 g / mol to 1,500 g / mol. All individual values and sub-ranges from 100 g / mol to 1,500 g / mol are included; for example, the polyol compound may have a number average molecular weight ranging 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, 1,250 g / mol, 1,000 g / mol or 900 g / mol.

[0062] Typically, the polyol compound may have a hydroxyl equivalent molecular weight of from 50 g / eq to 750 g / eq. All individual values and sub-ranges from 50 g / eq to 750 g / eq are included; for example, the polyol compound may have a hydroxyl equivalent molecular weight ranging 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.

[0063] Polyester polyols are typically obtained by the condensation of a polyol with a polyfunctional carboxylic acid having 2 to 12 carbon atoms (e.g., 2 to 6 carbon atoms). Typical polyols used to prepare polyester polyols are diols or triols and include ethylene glycol, diethylene glycol, polyethylene glycol such as PEG 200, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, pentylene glycol or hexylene glycol, polyether polyols, glycerol, etc. Typical polyfunctional carboxylic acids are selected from the group consisting of: succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decane dicarboxylic acid, maleic acid, fumaric acid and phthalic acid, isophthalic acid, terephthalic acid, isonaphthalenedicarboxylic acid and combinations thereof. The average OH functionality of the polyester polyol is preferably at least 1.8, even more preferably at least 2.0. Aromatic polyester polyols are a common type of polyester polyol used in rigid polyurethane foams.

[0064] As used herein, "aromatic polyester polyol" refers to a polyester polyol that includes an aromatic ring. For example, the aromatic polyester polyol may be phthalic anhydride diglycol polyester or may be prepared by using an aromatic dicarboxylic acid and a diol. The aromatic polyester polyol may be a hybrid polyester-polyether polyol, for example, as discussed in International Publication No. WO 2013 / 053555.

[0065] Aromatic polyester polyols can be prepared using known equipment and reaction conditions. In another embodiment, aromatic polyester polyols are commercially available. Examples of commercially available aromatic polyester polyols include, but are not limited to, those sold by Stepan Company under the trade name STEPANPOL TM (such as STEPANPOL TMPS-2352) Various polyols and the like for sale.

[0066] Polyether polyols typically have a hydroxyl functionality between 2 and 8, specifically 2 to 6, and are typically prepared by the polymerization of one or more alkylene oxides selected from propylene oxide (PO), ethylene oxide (EO), butylene oxide, tetrahydrofuran, and mixtures thereof with a suitable starting molecule or mixture of starting molecules in the presence of a catalyst. Typical starting molecules include compounds having at least two hydroxyl groups or at least one primary amine group in the molecule. Suitable starting molecules can be ethylene glycol, glycerol, trimethylolpropane, pentaerythritol, castor oil, sugar compounds such as glucose, sorbitol, mannitol, and sucrose, aliphatic amines and aromatic amines, polyphenols, resoles, oligomeric condensation products such as phenol and formaldehyde, and Mannich condensates of phenol, formaldehyde, and dialkanolamine, and melamine, etc.

[0067] By means of a starting molecule having at least 2 (e.g., 2 to 8) hydroxyl groups in the molecule, the following non-limiting examples can be further used: trimethylolpropane, glycerol, pentaerythritol, castor oil, sugar compounds such as glucose, sorbitol, mannitol, and sucrose, polyphenols, resoles, oligomeric condensation products such as phenol and formaldehyde, and Mannich condensates of phenol, formaldehyde, and dialkanolamine, and melamine. Catalysts for preparing polyether polyols can include basic catalysts for anionic polymerization, such as potassium hydroxide, or Lewis acid catalysts for cationic polymerization, such as boron trifluoride. Suitable polymerization catalysts can include potassium hydroxide, cesium hydroxide, boron trifluoride, or double cyanide complex (DMC) catalysts, such as zinc hexacyanocobaltate or phosphazene compounds. In one embodiment of the present disclosure, the number average molecular weight of the polyether polyol is in the range of 100 g / mol to 2,000 g / mol. For example, in the range of 125 g / mol to 1,500 g / mol, 150 g / mol to 1,250 g / mol, 150 g / mol to 1,000 g / mol, or 200 g / mol to 1,000 g / mol.

[0068] The polyether polyols suitable for the present invention can have an average hydroxyl functionality of 2.0 and are commonly referred to as diols. Diols can be ethylene glycol, propylene glycol, ethoxylates of ethylene glycol or propylene glycol, propoxylates of ethylene glycol or propylene glycol, etc. Examples of commercially available diols include, but are not limited to, those sold under the trade name VORANOL TM such as VORANOL TM 2110-TB and various polyols and the like purchased from The Dow Chemical Company.

[0069] The polyether polyols suitable for the present invention may have an average hydroxyl functionality of 3.0 and are commonly referred to as triols. The triols may be glycerol, trimethylolpropane, ethoxylated or propoxylated glycerol or trimethylolpropane, etc. The triols can be prepared using known equipment and reaction conditions. Examples of commercially available triols include, but are not limited to, the various polyols available from The Dow Chemical Company under the trade name VORATEC TM , such as VORATEC TM SD 301 sold.

[0070] The polyether polyols suitable for the present invention may include sucrose / glycerol-initiated polyether polyols. The sucrose / glycerol-initiated polyether polyols may include structural units derived from another alkylene oxide such as ethylene oxide or propylene oxide. The sucrose / glycerol-initiated polyether polyols may include structural units derived from styrene-acrylonitrile, polyisocyanate, and / or polyurea. The sucrose / glycerol-initiated polyether polyols can be prepared using known equipment and reaction conditions. For example, the sucrose / glycerol-initiated polyether polyols can be formed from a reaction mixture comprising sucrose, propylene oxide, and glycerol. One or more embodiments provide that the sucrose / glycerol-initiated polyether polyols are formed by the reaction of sucrose and propylene oxide. In another embodiment, the sucrose / glycerol-initiated polyether polyols are commercially available. Examples of commercially available sucrose / glycerol-initiated polyether polyols include, but are not limited to, those available under the trade name VORANOL TM such as VORANOL TM 360, VORANOL TM 490, and VORANOL TM 280, a variety of polyols purchased from The Dow Chemical Company (Dow).

[0071] The polyether polyols suitable for the present invention may include sorbitol-initiated polyether polyols. The sorbitol-initiated polyether polyols can be prepared using known equipment and reaction conditions. For example, the sorbitol-initiated polyether polyols can 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 polyols can be capped. For example, the alkylene oxide can be added in stages to preferentially locate or cap a specific alkylene oxide at the desired position of the polyol. The sorbitol-initiated polyether polyols are commercially available. Examples of commercially available sorbitol-initiated polyether polyols include, but are not limited to, those available from The Dow Chemical Company under the trade name VORANOL TM , such as VORANOL TM RN 482 sold.

[0072] The polyether polyols suitable for the present invention may include polyol compounds, which include amine-initiated polyols. The amine-initiated polyols may be initiated by aromatic amines or aliphatic amines. For example, the amine-initiated polyols may be o-tolylenediamine (o-TDA)-initiated polyols, ethylenediamine-initiated polyols, diethylenetriamine, triisopropanolamine-initiated polyols, or combinations thereof, etc. The amine-initiated polyols can be prepared using known equipment and reaction conditions. For example, the amine-initiated polyols can be formed from a reaction mixture containing an aromatic amine or an aliphatic amine and an alkylene oxide such as ethylene oxide and / or butylene oxide, etc. The alkylene oxide can be added to the alkoxylation reactor in one step or successively in several steps, and in each step, a single alkylene oxide or a mixture of alkylene oxides can be used.

[0073] Generally speaking, based on the total weight of all components in the foam-forming composition for preparing PUR / PIR foams, the amount of the polyol used herein can be in the range of about 10 wt% to about 80 wt%, or about 12 wt% to 70 wt%, or about 15 wt% to 60 wt%, or about 15 wt% to about 55 wt%, or about 15 wt% to about 50 wt%.

[0074] V. Optional Auxiliary Components

[0075] In addition to the above-mentioned at least one isocyanate-reactive component, at least one isocyanate component, at least one blowing agent, and at least one liquid silicone nucleating additive present in the foam-forming composition for preparing polyurethane / polyisocyanurate foams, the foam-forming composition of the present invention may further comprise other additional optional auxiliary components, compounds, reagents, or additives. Such optional components can be added to the reactive mixture together with any other components in the foam-forming composition (e.g., the isocyanate component, the isocyanate-reactive component, the blowing agent, or a liquid silicone nucleating additive) or added as a separate feed stream during foam preparation.

[0076] The optional auxiliary components, compounds, reagents, or additives that can be used in the present invention may include one or more various optional compounds known in the art for their uses or functions. For example, the optional components may include expandable graphite, additional physical or chemical blowing agents that may be the same as or different from the aforementioned blowing agents, blowing catalysts, flame retardants, emulsifiers, antioxidants, surfactants, compatibilizers, chain extenders, other liquid nucleating agents, solid nucleating agents, Ostwald ripening inhibitor additives, pigments, fillers, solvents, and also include solvents selected from the group consisting of ethyl acetate, methyl ethyl ketone, toluene, and mixtures of two or more of them; and mixtures of two or more of the above-mentioned optional additives.

[0077] Based on 100 pts of the total polyol amount in the isocyanate-reactive component, the amount of optional auxiliary compounds to be added to the foam-forming composition of the present invention can be, for example, 0 pts to 50 pts in one embodiment, 0.1 pts to 40 pts in another embodiment, and 1 pts to 35 pts in yet another embodiment. For example, in one embodiment, based on 100 pts of the total polyol amount in the isocyanate-reactive component, the amount of additional physical blowing agent (when used) can be 1 pts to 40 pts. In another embodiment, based on 100 pts of the total polyol amount in the isocyanate-reactive component, the amount of additional chemical blowing agent (when used) can be 0.1 pts to 10 pts. In another embodiment, based on 100 pts of the total polyol amount in the isocyanate-reactive component, the amount of flame retardant additive (when used) can be 1 pts to 25 pts. In yet another embodiment, based on 100 pts of the total polyol amount in the isocyanate-reactive component, the amount of surfactant (when used) is generally 0.1 pts to 10 pts. In even another embodiment, based on 100 pts of the total polyol amount in the isocyanate-reactive component, the amount of blowing catalyst (when used) is 0.05 pts to 5 pts. And in a general embodiment, based on 100 pts of the total polyol amount in the isocyanate-reactive component, the amount of other additives (when used) can be 0.1 pts to 10 pts.

[0078] Catalysts

[0079] The catalyst can include a urethane reaction catalyst and an isocyanate trimerization catalyst. The trimerization catalyst can be any trimerization catalyst known in the art that catalyzes the trimerization of organic isocyanate compounds. The trimerization of isocyanate can produce polyisocyanurate compounds inside the polyurethane foam. Without being limited by theory, the polyisocyanurate compounds can make the polyurethane foam harder and improve the fire reaction ability. The trimerization catalyst can include, for example, glycine salts, tertiary amine trimerization catalysts, alkali metal carboxylates, and mixtures thereof. In some embodiments, sodium N-2-hydroxy-5-nonylphenyl-methyl-N-methylglycinate can be employed. Based on 100 pts of the total polyol amount in the isocyanate-reactive component, when used, the trimerization catalyst can be present in an amount of 0.05 pts to 5 pts (for example, 0.1 pts to 3.5 pts, or 0.2 pts to 2.5 pts, or 0.5 pts to 2.5 pts).

[0080] Tertiary amine catalysts include organic compounds containing at least one tertiary nitrogen atom and capable of catalyzing the hydroxyl / isocyanate reaction between the isocyanate component and the isocyanate-reactive component. By way of example and not limitation, tertiary amine catalysts can include triethylenediamine, tetramethylethylenediamine, pentamethyldiethylenetriamine, bis(2-dimethylaminoethyl) ether, triethylamine, tripropylamine, tributylamine, tripentylamine, pyridine, quinoline, dimethylpiperazine, piperazine, N-ethylmorpholine, 2-methylpropanediamine, methyltriethylenediamine, 2,4,6-tris(dimethylamino-methyl)phenol, N,N',N”-tris(dimethylamino-propyl)hexahydrotriazine, and mixtures thereof. When used, the tertiary amine catalyst can be present in an amount of 0.05 pts to 5 pts (e.g., 0.1 pts to 3.5 pts, or 0.2 pts to 2.5 pts, or 0.5 pts to 2.5 pts) based on 100 pts of the total polyol amount in the isocyanate-reactive component.

[0081] The compositions of the present disclosure may also contain the following catalysts: tertiary phosphines such as trialkylphosphines and dialkylbenzylphosphines; chelates of various metals such as those obtainable from acetylacetone, benzoylacetone, trifluoroacetylacetone, ethyl acetoacetate, etc. with metals such as Be, Mg, Zn, Cd, Pd, Ti, Zr, Sn, As, Bi, Cr, Mo, Mn, Fe, Co, and Ni; acidic metal salts of strong acids such as iron chloride, tin chloride; salts of organic acids with various metals such as alkali metals, alkaline earth metals, Al, Sn, Pb, Mn, Co, Ni, and Cu; organotin compounds such as tin(II) salts of organic carboxylic acids, e.g., tin(II) diacetate, tin(II) dioctanoate, tin(II) diethylhexanoate, and tin(II) dilaurate, and dialkyltin(IV) salts of organic carboxylic acids, e.g., dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, and dioctyltin diacetate; bismuth salts of organic carboxylic acids such as bismuth octanoate; organometallic derivatives of trivalent and pentavalent As, Sb, and Bi, and metal carbonyls of iron and cobalt. In one embodiment, based on 100 pts of the total polyol amount in the isocyanate-reactive component, the total amount of the catalyst components used herein in the polyol package can generally be in the range of about 0.01 pts to about 10 pts, and 0.05 pts to about 5 pts.

[0082] Surfactants

[0083] The foam-forming composition of the present invention may comprise a surfactant. For example, the surfactant may be added to any one of the components of the foam-forming composition or added as a separate stream during foam preparation. The surfactant may be a cell-stabilizing surfactant. Examples of surfactants useful in the present invention include silicone-based compounds such as silicone-polyether copolymers such as polydimethylsiloxane-polyoxyalkylene block copolymers, for example polyether-modified polydimethylsiloxane and combinations thereof. Surfactants are commercially available and include those available under trade names such as NIAXT TM such as NIAX TM L 6988 and TEGOSTAB TM such as TEGOSTAB TM B 8462 and the like. Examples of surfactants also include non-silicone-based organic surfactants such as VORASURF TM 504 purchased from The Dow Chemical Company.

[0084] Other surfactants useful herein are polyethylene glycol ethers of long-chain alcohols, long-chain alkenyl sulfates, alkyl sulfonates, tertiary amine or alkanolamine salts of alkyl aryl sulfonic acids, and combinations thereof. Such surfactants are employed in an amount sufficient to stabilize the foaming reaction, prevent collapse, and form larger non-uniform cells. Based on 100 pts of the total polyol present in the isocyanate-reactive component, when used, the amount of surfactant may be from 0.1 pts to 10.0 pts. All individual values and subranges including from 0.1 pts to 10.0 pts are included; for example, based on 100 pts of the total polyol present in the isocyanate-reactive component, the surfactant may have a lower limit of 0.1 pts, 0.2 pts, or 0.3 pts to an upper limit of 10.0 pts, 9.0 pts, 7.5 pts, or 6 pts.

[0085] Additional Blowing Agents

[0086] In various embodiments, the foam-forming composition of the present invention may comprise an additional blowing agent that may be the same as or different from component (C). The additional blowing agent may be incorporated into either component (A) or (B) prior to foam preparation or added as a separate stream and mixed online with components (A), (B), (C), and (D) during foam preparation. The additional blowing agent may be selected at least in part based on the desired density of the final foam.

[0087] A variety of conventional blowing agents may be used. For example, the blowing agent may be one or more of the following: water, various hydrocarbons, various hydrofluorocarbons, various hydrofluoroolefins, formic acid, inert gases, various chemical blowing agents that produce nitrogen or carbon dioxide under the foaming reaction conditions, etc.; and mixtures thereof.

[0088] Chemical blowing agents (such as water) can be used alone or in combination with other chemical and / or physical blowing agents. Also suitable as chemical blowing agents are organic carboxylic acids such as formic acid, acetic acid, oxalic acid and carboxyl group-containing compounds.

[0089] Physical blowing agents can be used such as low-boiling hydrocarbons. Examples of such liquids used are alkanes such as heptane, hexane, n-pentane and isopentane; industrial grade mixtures of n-pentane and isopentane and of n-butane and isobutane with 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 vinyl lactate; and halogenated hydrocarbons such as dichloromethane, dichlorofluoromethane, difluoromethane, trifluoromethane, difluoroethane, tetrafluoroethane, chlorodifluoroethane, 1,1-dichloro-2,2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane, hexafluorobutene; various hydrochlorofluorocarbons (HCFC), hydrofluorocarbons (HFC) and hydrofluoroolefins (HFO) such as 1,1-dichloro-2,2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane, pentafluoropropane, heptafluoropropane, hexafluorobutene, (E,Z)1,1,1,4,4,4-hexafluoro-2-butene and trans-1-chloro-3,3,3-trifluoropropene, trans-1,3,3,3-tetrafluoroprop-1-ene, 1,3,3,3-tetrafluoropropene etc. Some of these blowing agents are commercially available materials called LBA, GBA, Opteon TM 1100, Opteon TM 1150 etc. Mixtures of these low-boiling liquids with each other and / or with other substituted or unsubstituted hydrocarbons can also be used.

[0090] In various embodiments, based on 100 pts of the total polyol amount in the isocyanate-reactive components, the amount of additional blowing agent is from about 0.1 pts to about 40 pts (e.g., from about 0.5 pts to about 35 pts, 1 pts to 30 pts, or 5 pts to 25 pts).

[0091] Other Optional / Auxiliary Additives

[0092] Other optional / auxiliary compounds or additives that can be used in the foam-forming compositions of the present invention to prepare polyurethane / polyisocyanurate foams can include, for example, other auxiliary catalysts, auxiliary surfactants, toughening agents, flow modifiers, tackifiers, diluents, stabilizers, plasticizers, dispersants, flame retardant (FR) additives and mixtures thereof.

[0093] In various embodiments, the fire resistance performance can be enhanced by including one or more flame retardants. The flame retardants can be halogenated or non - halogenated, and can include, for example but not limited to, tris(1,3 - dichloro - 2 - propyl) phosphate, tris(2 - chloroethyl) phosphate, tris(2 - chloropropyl) phosphate, triethyl phosphate, diammonium phosphate, various halogenated aromatic compounds, antimony oxide, aluminum trihydrate, and combinations thereof. Based on 100 pts of the total polyol amount in the isocyanate - reactive components, when used, the flame retardant can be present in an amount of 0.1 pts to about 30 pts, or about 1 pts to 25 pts, or about 2 pts to about 25 pts, or about 5 pts to about 25 pts.

[0094] Other additives such as fillers and pigments can be included to prepare the PIR / PUR foam. In non - limiting embodiments, such fillers and pigments can include barium sulfate, calcium carbonate, graphite, carbon black, titanium dioxide, iron oxide, microspheres, aluminum trihydrate, wollastonite, glass fiber, polyester fiber, other polymeric fibers, combinations thereof, etc.

[0095] VI. Method for Preparing Foams

[0096] In various embodiments, the PIR / PUR foam is prepared by mixing all the individual components (including at least one isocyanate - reactive component, at least one isocyanate component, at least one blowing agent, and at least one liquid silicone nucleating additive present) with any optional auxiliary additives (such as catalysts, surfactants, additional blowing agents, and any other additives) at room temperature or at an elevated temperature of 25 °C to 120 °C (e.g., 30 °C to 90 °C or 40 °C to 70 °C) for a duration of 1 second to 20 seconds, and then immediately pouring, spraying, injecting, or laying the resulting mixture into a mold cavity or substrate for foaming. In some embodiments, optional auxiliary additives such as catalysts, flame retardants, additional blowing agents, and surfactants, etc., can be added to the isocyanate - reactive component or the isocyanate component before mixing with the other components, or can be mixed online as a separate stream with the other components.

[0097] Mixing can be carried out in a spraying device, mixing head or container. Immediately after mixing, the foaming mixture is sprayed or otherwise deposited or injected or poured onto a substrate or into a mold. Regardless of any particular method of foam production, when the foam expands and cures, the amount of the foaming mixture introduced into the mold or onto the substrate is sufficient to completely fill the mold or take the shape of a plate or any other functional shape. Even a certain degree of overfilling can be introduced by using a slightly excessive amount of the reaction mixture beyond the minimum required amount. For example, the cavity can be overfilled by 5% to 35%, i.e., 5 wt% to 35 wt% more of the reaction system, than the minimum requirement for filling the cavity when the reaction mixture is fully expanded under the predetermined manufacturing conditions. This cavity can optionally be maintained at atmospheric pressure or partially evacuated to sub-atmospheric pressure.

[0098] After reaction, the foaming mixture takes the shape of the mold or adheres to the substrate to produce a PIR / PUR foam, and then is partially or fully cured. Conditions suitable for promoting the curing of PIR / PUR polymers include temperatures from about 20 °C to about 150 °C. In some embodiments, the curing is carried out at a temperature from about 30 °C to about 75 °C. In other embodiments, the curing is carried out at a temperature from about 35 °C to about 65 °C. In various embodiments, the temperature for curing can be selected at least partially based on the duration required for the PUR / PIR polymer to gel and / or cure at that particular temperature. The curing time will also depend on other factors, including for example the amount of specific components used (e.g., the type and amount of its catalyst), and the size and shape of the article being manufactured. The different articles prepared can include, but are not limited to, foam boards for roofs, insulation boards for construction and building purposes, and door panels for appliances, etc.

[0099] VII. Foam Properties

[0100] In a general embodiment, the rigid polyurethane or polyisocyanurate foam prepared from the foam-forming composition of the present invention has a density of 20 kg / m 3 to 200 kg / m 3 . In an exemplary embodiment, the density of the rigid polyurethane or polyisocyanurate foam can be 20 kg / m 3 to 150 kg / m 3 in one embodiment, 25 kg / m 3 to 100 kg / m 3 in another embodiment, 25 kg / m 3 to 75 kg / m 3 in another embodiment, 25 kg / m 3 to 60 kg / m 3 in yet another embodiment, and 30 kg / m 3Up to 60 kg / m 3 。

[0101] The rigid polyurethane or polyisocyanurate foams of the present invention also exhibit several beneficial properties such as low thermal conductivity (improved heat insulation performance). For example, the foams of the present invention exhibit a low thermal conductivity of no more than 20.6 mW / m-K at 10 °C in one general embodiment, 16.0 mW / m-K to 20.5 mW / m-K in another embodiment, 16.5 mW / m-K to 20 mW / m-K in another embodiment; 17.0 mW / m-K to 19.5 mW / m-K in yet another embodiment, and 17.0 mW / m-K to 19.0 mW / m-K in yet another embodiment. The insulation performance of the rigid foams of the present invention, as measured by thermal conductivity (or "K factor"), is defined and determined by the procedures described in ASTM C518-04 (2010).

[0102] In addition, the foams of the present invention advantageously exhibit good mechanical properties as measured by the compressive strength determined by the procedures described in ASTM D-1621. For example, in one general embodiment, the foam exhibits a compressive strength value of not less than 100 KPa. Foams with a compressive strength below 100 KPa are generally considered to lack sufficient mechanical strength for long-term use.

[0103] The present invention regarding the use of liquid silicone nucleating additives to prepare foams with improved heat insulation performance brings several advantages to the polymer foam industry. Since many blowing agents and nucleating additives used to prepare polyurethane or polyisocyanurate foams are fluorine compounds known to cause global warming problems, the use of liquid silicone nucleating additives as described herein may allow for reduced emissions of global warming materials during manufacturing and subsequent use. Additionally, the present invention can be used to prepare foams with higher thermal efficiency, which can be used to manufacture more energy-efficient products that can reduce pollution emissions.

[0104] The foregoing description is intended to be general and is not intended to include all possible embodiments. Similarly, the examples provided below are merely illustrative and are not intended to limit or restrict the claimed subject matter in any way. Those skilled in the art will be fully aware that other embodiments within the scope of the claims will be apparent by considering the specification and / or practice of the methods disclosed herein. Such other embodiments may include the selection of specific components and their ingredients and proportions; mixing and reaction conditions, vessels, deployment equipment and schemes; performance and selectivity; identification of products and by-products; subsequent processing and their uses; etc.; and those skilled in the art will recognize that such embodiments may vary within the scope of their appended claims.

[0105] Examples

[0106] Materials

[0107] In the examples, two aromatic polyester polyols were used. They were prepared using aromatic dicarboxylic acids and polyglycols such as DEG, PEG200, glycerol, etc. Polyol A had an OH value of 220 mg KOH / g, a number average molecular weight of 510 g / mol, and an OH functionality of 2.0. Polyol B had an OH value of 315, a number average molecular weight of 427, and an OH functionality of 2.4.

[0108] In the examples and comparative examples, various foaming additives were used, such as catalysts, surfactants, FR additives, and physical blowing agents, etc. For example, Dabco K-2097 (Catalyst A) is a trimer catalyst purchased from Evonik; Polycat 5 (Catalyst B) is a foaming catalyst for polyurethane foaming purchased from Evonik. Surfactant A is a silicone polyether surfactant purchased from Evonik, and TEP (FR additive) is a triethyl phosphate flame retardant purchased from ICL-IP. Additionally, a fluorine compound 3M TM FA-188 (perfluorocarbon) was used as a nucleating additive for foam preparation.

[0109] In the examples and comparative examples, a variety of liquid silicone additives were used. They were all purchased from Gelest, Inc. in Morrisville, Pennsylvania, USA, and are listed in Table 1 below. Silicone additives A - C are the additives disclosed in the present invention, and silicone additives D and E are comparative materials.

[0110] Table 1. Liquid Siloxane Additives

[0111]

[0112]

[0113] The structures of each of the silicone additives A - E can be seen below.

[0114]

[0115] The polyisocyanates used in all examples and comparative examples of the present invention were commercially manufactured by Dow: PAPI 580N or Voranate M600. They are polymeric MDI having an NCO% of 30.8, an average isocyanate functionality of 3.0, and a viscosity at 25 °C of about 600 mPa.

[0116] The physical blowing agent used in all the examples and comparative examples of the present invention is a 70 / 30 blend of cyclopentane and isopentane, also known as the cyclo / isopentane blend (70 / 30).

[0117] General Protocol for Foam Preparation

[0118] Various foams were prepared by manual mixing using a overhead mixer as follows. The polyol, surfactant, flame retardant, catalyst and water were added to a plastic cup, and the plastic cup and its contents were weighed. Then, the cup contents were mixed with a high-speed overhead mixer to provide a "polyol pack" (i.e., side B). Then, the target amount of physical blowing agent and liquid silicone nucleating additive (if used) were added to the cup and thoroughly mixed with the polyol pack. Subsequently, the required amount of polyisocyanate component (i.e., side A) was added to the formulation mixture in the cup. Then, the resulting complete foam formulation was immediately mixed with a high-speed overhead mixer at 3,000 rpm for 5 seconds and then immediately poured into a vertical plate mold preheated to 55 °C. The vertical plate mold was sized 30 cm (height) × 20 cm (length) × 5 cm (width). The mold was placed vertically in its "height" direction for foaming. After curing for about 20 minutes inside the mold, the foam was removed from the mold and left overnight on the laboratory bench before physical property testing.

[0119] A high-pressure foaming machine (model: Cannon AP10) was also used for foam preparation. For the foams prepared by the high-pressure machine, all the required foaming components except the isocyanate component were premixed together and loaded into a tank for use. The isocyanate component was loaded into a separate tank. The foam formulation components from the two tanks were mixed using a high-pressure impact mixer, and the resulting foaming mixture was injected into the mold for curing. Two different molds were used for foam preparation. The first mold was a vertical plate mold sized 30 cm (height) × 20 cm (length) × 5 cm (width), and the second mold was a flat mold sized 30 cm (length) × 30 cm (width) × 10 cm (thickness or height). The "height" direction of each mold corresponded to the foam foaming direction during foam preparation. Both molds were also preheated to 55 °C and maintained at 55 °C throughout the duration of foam preparation. All the foams prepared by running the high-pressure machine were cured inside the mold for 5 minutes, then removed from the mold and left overnight on the laboratory bench before physical property testing.

[0120] Characterization and Property Measurements

[0121] The cream time and the gel time are determined according to the test procedures described in ASTM D7487 (2013). The general procedures for cream time and gel time measurements include the following: Free - rising foam is prepared by the above - described plastic cup method. Using this method, polyol, surfactant, flame retardant, catalyst, and water are weighed into a plastic cup. A high - speed mixer is used to mix the polyol components. Subsequently, an appropriate amount of blowing agent is added to the cup and thoroughly mixed into the polyol side components. Then the isocyanate component is added to the cup, and immediately thereafter, a overhead mixer is used to mix at approximately 3,000 rpm for 5 seconds. Time is recorded when the mechanical mixing of the isocyanate and polyol side mixture begins. When the foam formulation in the cup shows an obvious color or appearance change (or more commonly referred to as creamification) due to the formation of a large number of bubbles, then the time is recorded as the "cream time". Subsequently, the tip of a wooden tongue depressor is dipped into the foam formulation and quickly pulled out to check if the foaming mixture has become viscous. Based on the wooden tongue depressor test, the time when the foaming formulation becomes viscous is recorded as the "gel time".

[0122] Within 24 hours after foam preparation (after leaving it overnight on the laboratory bench), a foam sample with dimensions of 20 cm×20 cm×2.5 cm is cut from the middle - inner part of the molded foam for thermal conductivity measurement. The measurement is carried out at 50°F according to the procedures described in ASTM C518 - 04 (2010). The accuracy of the K - factor measurement is typically within 0.1 mW / m - K. The average value of the K - factor measurements of at least two test samples for each example and comparative example is reported.

[0123] The density of the rigid foam is measured according to the procedures described in ASTM 1622 - 03 (2008). Cubic samples with dimensions of 5 cm×5 cm×5 cm are cut from the middle - inner part of the molded foam for measurement. The density of each sample is calculated by weighing the mass and measuring its exact dimensions. At least three samples of each foam sample are measured, and their average value is reported.

[0124] The open - cell content of the formed rigid PU foam is measured according to ASTM D - 6226. This measurement is carried out using a pycnometer AccuPyc 1330 equipped with a FoamPyc option for calculating the open - cell content, obtained from Micromeretics (Norcross, GA). Five samples with nominal dimensions of 1”x1”x1” are taken from different positions of the entire foam sample and measured. Any sample with obvious defects is excluded from the test by visual inspection. Before measurement, all samples are conditioned for at least 24 hours under ASTM standard laboratory conditions. Then the average value of the open - cell content is reported.

[0125] The compressive strength of the foam sample formed by measuring the mechanical resistance of the foam to compressive stress. This test is carried out perpendicular to the foaming direction of the foam (x-axis) or parallel to it (z-axis). The test is performed on 5 cm × 5 cm × 2.5 cm foam samples taken from the middle internal part of the foam prepared by a flat die according to the ASTM D-1621 method.

[0126] According to the procedure described in ASTM C 421 (2014), the brittleness of the formed foam is measured by testing the foam sample in a tumbling machine. The device consists of an oak cube box with internal dimensions of 7 1 / 2 inches × 7 3 / 4 inches × 7 3 / 4 inches (190 mm × 197 mm × 197 mm). The box shaft is a motor driven at a constant speed of 60 ± 2 revolutions per minute. Twenty-four 3 / 4 ± 1 / 32 inch (19 mm ± 0.8 mm) cubes of solid oak dried at room temperature are placed in the box together with the test sample. The test sample is prepared by cutting the internal part of the molded foam into 1 ± 1 / 16 inch (25.4 ± 1.6 mm) cubes with a fine-tooth saw.

[0127] By using Porescan β system to analyze a 2 cm × 1 cm × 0.5 cm sample to measure the cell size analysis of the formed foam. PoreScan β is an automatic cell size analysis instrument manufactured by Goldlucke Ingenieurleistungen. The system includes a camera and software components. The contrast liquid (provided by Goldlucke Ingenieurleistungen) is deposited on the foam sample by spraying and consists of carbon black in pentane with propane and butane as propellants. The foam sample treated with the contrast agent is imaged by the camera and processed by the software. For each sample, at least 5000 cells are imaged and analyzed. The average cell size in micrometers (μm) is reported in Table 3.

[0128] Examples 1 - 3 and Comparative Examples A - C

[0129] For Comparative Example A, 180 grams of the foaming mixture was prepared according to the general procedure described in the method of preparing the foam by manual mixing discussed above. Immediately pour the foaming mixture into a vertical upright plate mold of 30 cm (height) × 20 cm (length) × 5 cm (width). For this specific formulation, approximately 135 grams of the foaming mixture was poured into the mold. After 20 minutes, the formed foam was removed from the mold and placed on the laboratory bench overnight before physical property testing. The foam property results are summarized in Table 2 below.

[0130] Example 1 was prepared by mixing 2 parts of silicone additive A based on a total polyol amount equal to 100 parts into a premixed blend of polyol, catalyst, surfactant, FR additive, and water (or as shown in Table 2, 1.62 parts of silicone additive per total 81.2 pts of polyol), then adding the desired amount of physical blowing agent and mixing, and preparing the foam by following the detailed formulation described in Table 2 and a similar manual mixing protocol as in Comparative Example A. The foam properties of Example 1 are also summarized in Table 2.

[0131] Examples 2 - 3 and Comparative Examples B - C repeated the protocol of Example 1, except that each foam was prepared using different silicone additives according to Table 2. The foam properties of all these examples are reported in Table 2.

[0132] Table 2. Foam-Forming Compositions in PIR Systems

[0133]

[0134]

[0135] The results in Table 2 show that the thermal conductivity or K - factor of the foams prepared from the foam - forming compositions containing the silicone nucleating additives disclosed in the present invention is significantly lower than that of the foams without any silicone additives (e.g., Comparative Example A) or containing less desirable silicone additives (e.g., Comparative Examples B and C).

[0136] Examples 4 - 5 and Comparative Examples D - E

[0137] Table 3 shows the details of the foam - forming compositions of Comparative Examples D - E and Examples 4 - 5 and the properties of the foams prepared from these compositions using a high - pressure machine (model: Cannon AP10). Comparative Example D contains no liquid silicone nucleating additive and no other type of nucleating agent. Comparative Example E contains 2 parts of a non - silicone type nucleating agent FA - 188 but no silicone nucleating additive. Example 4 contains 2 parts of silicone nucleating additive C (SIO6715.7) but no nucleating agent FA - 188. Example 5 contains both silicone nucleating additive C and non - silicone type nucleating agent FA - 188.

[0138] Both the vertical plate mold and the flat plate mold were used for the foam preparation in Comparative Examples D - E and Examples 4 - 5. The K - factor values of the samples cut from the middle inner part of these two molds were measured. Additionally, a sandwich metal plate with a thin metal surface layer on the top and bottom of the foam was prepared using the flat plate mold. The sandwich metal plate was aged for two weeks, and then the middle inner part of the foam core was cut for K - factor measurement, hereinafter referred to as the "K - factor after aging". The detailed foam characteristics and the analysis results of the foam cell size of Comparative Examples D - E and Examples 4 - 5 are shown in Table 3.

[0139] Table 3. Foam-Forming Compositions

[0140]

[0141]

[0142] Note: "nm" in the table indicates "not measured".

[0143] The results in Table 3 show that compared with Comparative Example D, the foam of Example 4 using the liquid silicone nucleating additive C exhibits excellent foam characteristics such as low thermal conductivity, smaller cell size, similar mechanical properties, etc. Additionally, the comparison between Example 5 and Comparative Example E shows that when a non - siloxane type nucleating additive such as 3M TM FA - 188 is present in the foam formulation, the novel silicone nucleating additive disclosed in the present invention can lead to a further reduction in the thermal conductivity (K - factor).

Claims

1. A foam-forming composition for preparing polyisocyanurate and polyurethane foams, the foam-forming composition comprising: at least one polyisocyanate compound; at least one isocyanate-reactive compound; at least one blowing agent; 0.1 to 5 parts by weight of at least one liquid silicone nucleating additive per 100 parts by weight of the at least one isocyanate-reactive compound; Among them, the at least one liquid silicone nucleating additive is soluble in the at least one blowing agent; and, the at least one liquid silicone nucleating additive has the following structure: wherein, R1 is a C1 to C4 alkyl group or a tris(methyl)siloxy group, and R2 is a C5 to C18 alkyl group, a C5 to C18 cycloalkyl group or a C7 to C18 aralkyl group.

2. The foam-forming composition according to claim 1, wherein the at least one blowing agent is selected from the group consisting of aliphatic hydrocarbons having 3 to 7 carbon atoms, cycloaliphatic hydrocarbons having 3 to 7 carbon atoms, hydrofluoroolefins, or mixtures thereof.

3. The foam-forming composition according to claim 1, wherein per 100 parts by weight of the at least one isocyanate-reactive compound, the amount of the at least one blowing agent is 0.1 pts to 40 pts.

4. The foam-forming composition according to claim 2, wherein per 100 parts by weight of the at least one isocyanate-reactive compound, the amount of the at least one blowing agent is 0.1 pts to 40 pts.

5. The foam-forming composition according to any one of claims 1 to 4, wherein the molar ratio of the at least one liquid silicone nucleating additive to the blowing agent is 1:100 to 1:

10.

6. The foam-forming composition according to any one of claims 1 to 4, wherein the amounts of the at least one polyisocyanate compound and the at least one isocyanate-reactive compound are such that the isocyanate index is between 100 and 600.

7. The foam-forming composition according to any one of claims 1 to 4, wherein the composition further comprises at least one optional auxiliary additive selected from the group consisting of surfactants, catalysts, additional physical blowing agents, additional chemical blowing agents, flame retardant additives, nucleating agents, or mixtures thereof.

8. A method for preparing polyurethane and polyisocyanurate foams using the foam-forming composition according to any one of claims 1 to 7, the method comprising mixing the polyisocyanate compound, the isocyanate-reactive compound, the at least one liquid silicone nucleating additive, the at least one blowing agent, and any optional auxiliary additives.

9. The method for preparing polyurethane and polyisocyanurate foams according to claim 8, wherein the at least one liquid silicone nucleating additive is premixed with the at least one blowing agent or any optional auxiliary additives.

10. A polyurethane and polyisocyanurate foam prepared with a foam-forming composition according to any one of claims 1 to 7, wherein the foam density is between 25 and 100 kg / m 3 and the thermal conductivity of the polyurethane and polyisocyanurate foam product measured at 10 °C and within 24 hours of the foam preparation according to the procedure in ASTM C518-04 2010 is less than or equal to 20.6 mW / m·K.

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