Imidyl-containing polyester polyols and expanded rigid foams

Abstract

Disclosed are rigid polyurethane or polyisocyanurate foams, polyester polyols for producing the foams, and methods for preparing the foams. The foams comprise the reaction products of polyisocyanates, polyester polyols, water, surfactants, catalysts, and optional ingredients. The polyester polyols comprise polyacids containing phthalimide, polyols containing phthalimide, or combinations thereof. The rigid foams produced by the polyester polyols exhibit higher thermal stability and / or greater expansibility than foams made from other polyester polyols. The polyester polyols containing phthalimide should allow formulators to improve the flammability properties of rigid foams while reducing the content of flame retardants and / or lowering the index and should facilitate the production of thinner insulation boards.

Description

Technical Field

[0001] The present invention relates to polyester polyols containing phthalimide and their use for producing rigid polyurethane or polyisocyanurate foams having improved heat resistance and expansion properties. Background Art

[0002] Rigid polyurethane (PU) or polyisocyanurate (PIR) foams are common insulation materials. Foams must pass well-defined, region-specific flammability tests. Flame retardants are incorporated into foams to reduce flammability. However, common flame retardants are expensive, and many of them—especially halogenated ones—are under increasing regulatory pressure. In addition, even with flame retardants, flammability requirements can be difficult to meet.

[0003] Polyester polyols are typically used to produce rigid PU or PIR foams. Some polyols are better than others at imparting desirable flammability properties to foams; desirable properties include low mass loss, reduced smoke generation, and better char formation (i.e., better expansion). In some cases, ethylene terephthalate polyesters have been used to improve foam flammability.

[0004] Further improvements in the flammability properties attributable to polyester polyols are desirable. These improvements would allow formulators to achieve acceptable flammability characteristics at reduced flame retardant levels and reduced polyisocyanate ratios. Additionally, thinner rigid foam insulation boards could be manufactured with good flame retardancy.

[0005] Polyimides, polymers prepared, for example, by reacting dianhydrides (such as pyromellitic dianhydride) with aromatic diamines or with diisocyanates, are used in applications requiring high thermal stability. Polyimides have not been widely used in building insulation due to their high cost and relatively poor insulating properties. Instead, they are mainly used in special applications such as electronic devices requiring high thermal stability, chemical resistance and good dielectric properties.

[0006] The construction industry would benefit from the availability of polyester polyols with improved thermal stability and the ability to produce rigid PU and PIR foams with improved flammability properties. The desired polyols would allow formulators of rigid foams to reduce their reliance on traditional flame retardants and high polyisocyanate content, passing industry standard flammability tests. Ideally, the polyols would be economical and easy to synthesize from readily available starting materials. Summary of the invention

[0007] In one aspect, the present invention relates to a rigid polyurethane or polyisocyanurate foam. The foam comprises a reaction product of a polyisocyanate, a polyester polyol, water, a surfactant, a catalyst, and optional ingredients. The polyester polyol comprises repeating units of a polyacid containing phthalimide, a polyol containing phthalimide, or a combination thereof.

[0008] In other aspects, the present invention includes polyester polyols comprising repeating units of terephthalic acid, diethylene glycol and polyacids containing phthalimide, polyols containing phthalimide, or combinations thereof. In some aspects, the polyester polyols have a hydroxyl value in the range of 150 to 800 mg KOH / g and an acid value in the range of 0.1 to 5 mg KOH / g.

[0009] The present invention comprises a process comprising formulating a rigid polyurethane or polyisocyanurate foam by reacting a polyisocyanate and a polyester polyol as described above with water, a surfactant, a catalyst and optional ingredients.

[0010] Rigid PU and PIR foams produced from the polyester polyols exhibit improved flame retardancy, higher thermal stability and / or greater expansibility compared to rigid foams prepared from conventional polyester polyols. This allows the foams to pass flammability tests with reduced flame retardant content and reduced polyisocyanate requirements (lower NCO / OH index). It also facilitates the production of thinner insulation boards with acceptable flame retardancy. The polyols can be synthesized from readily available starting materials. DETAILED DESCRIPTION

[0011] A. Rigid PU and PIR foam

[0012] In some aspects, the present invention relates to rigid polyurethane (PU) or polyisocyanurate (PIR) foams. PU foams will have predominantly urethane linkages, but may have a smaller proportion of urea and / or isocyanurate content, while PIR foams (also commonly referred to as polyurethane-modified polyisocyanurate foams or "PU-PIR foams") will have predominantly isocyanurate content and may have a smaller proportion of urethane and / or urea groups.

[0013] The foam comprises the reaction product of a polyisocyanate, a polyester polyol, water, a surfactant, a catalyst, and optional ingredients.

[0014] 1. Polyisocyanate

[0015] Polyisocyanates suitable for use are well known and many are available from DDoW Chemical (as PAPI TM , and VORONATETM Trademark), Evonik BASF Covestro and ), Huntsman and other polyurethane intermediate suppliers. Suitable polyisocyanates for use have an average NCO functionality in the range of 2.0 to 3.0. The polyisocyanate can be aromatic or aliphatic. Aromatic polyisocyanates include, for example, toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI) or polymeric diisocyanate (p-MDI), etc. Aliphatic polyisocyanates include, for example, hexamethylene diisocyanate (HDI), hydrogenated MDI, cyclohexane diisocyanate (CHDI), isophorone diisocyanate (IPDI), trimethyl or tetramethyl hexamethylene diisocyanate (TMXDI), etc. Aromatic polyisocyanates are preferred, especially polymeric MDI with an NCO functionality in the range of 2.3 to 3.0. Suitable polymeric MDIs include, for example M10 (average NCO functionality = 2.3), M20 (average NCO functionality = 2.7) and M70L (average NCO functionality = 3.0), products from BASF, and 489 (modified polymeric MDI, average NCO functionality = 2.9, a product of Covestro). Mixtures of different polyisocyanates can be used. Dimeric and trimeric polyisocyanates can be used. In some aspects, aromatic polyisocyanates, such as p-MDI, are preferred.

[0016] Rigid foams can be formulated over a wide range of indices. As used herein, "index" means the ratio of isocyanate to hydroxyl equivalents multiplied by 100. Rigid PU foams are produced with relatively low indices, such as 90 to 150, while rigid PIR foams are typically produced with relatively high indices, such as 180 to 350.

[0017] 2. Polyester polyols containing phthalimide-containing reactants

[0018] The polyester polyol comprises repeating units of a phthalimide-containing polyacid, a phthalimide-containing polyol, or a combination thereof.

[0019] a. Phthalimide-containing polyacid

[0020] Suitable phthalimide-containing polyacids have two or more, preferably two or more, carboxylic acid groups.In some aspects, the phthalimide-containing polyacid is a phthalimide-containing diacid.

[0021] In some aspects, the phthalimide-containing polyacid is the reaction product of trimellitic anhydride and an amino acid. In some aspects, the amino acid is glycine, alanine, phenylalanine, serine, or threonine.

[0022] In other aspects, the polyacid containing phthalimide is the reaction product of phthalic anhydride or trimellitic anhydride and an amino acid selected from aspartic acid and glutamic acid. In these aspects, when phthalic anhydride is used, the polyacid containing phthalimide is a diacid, and when trimellitic anhydride is used, the polyacid containing phthalimide is a triacid.

[0023] In some aspects, the phthalimide-containing polyacid is a diacid having the structure:

[0024]

[0025] Where R 1 and R 2 Each is independently hydrogen, alkyl, hydroxyalkyl, haloalkyl or alkoxy, and n has a value of 0 to 4. In other aspects, R 1 and R 2 Each is independently hydrogen, methyl, methoxy or 2-hydroxyethyl. 1 and R 2 are each independently hydrogen or methyl.

[0026] b. Phthalimide-containing polyols

[0027] The polyol containing phthalimide can have two or more hydroxyl groups, or 2 to 7 or 2 to 3 hydroxyl groups. Combinations of polyols with different hydroxyl functionalities can be used. In some aspects, the polyol containing phthalimide is a diol or triol containing phthalimide.

[0028] In some respects, the polyol containing phthalimide is the reaction product of aliphatic amino alcohol, diol or polyol and trimellitic anhydride. Suitable aliphatic amino alcohol has primary amino group and hydroxyl group. In some respects, aliphatic amino alcohol has 2 to 20 carbon or 2 to 10 carbon or 2 to 4 carbon. Example includes ethanolamine (EA), 2-(2-aminoethoxy) ethanol (AEE), 2-[2-(2-(aminoethoxy) ethoxy] ethanol etc., and their mixture. In some respects, amino alcohol is ethanolamine or 2-(2-aminoethoxy) ethanol.

[0029] Suitable glycols and polyols are straight or branched aliphatic compounds with two or more hydroxyl groups. In some cases, the hydroxyl group is located on the adjacent carbon. Suitable glycols and polyols include, for example, ethylene glycol, propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2-methyl-1,3-propanediol, pentaerythritol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,6-hexanediol, tripropylene glycol, tetraethylene glycol, polyethylene glycol with a number average molecular weight of 250 to 1000 g / mol, glycerol, trimethylolethane, trimethylolpropane, sucrose, sorbitol, etc., and mixtures thereof. In some aspects, the diol or polyol is ethylene glycol, diethylene glycol, triethylene glycol, or a combination thereof.

[0030] In some aspects, the polyol containing phthalimide is the reaction product of a bis(anhydride) and two molar equivalents of an aliphatic amino alcohol. A bis(anhydride) has two anhydride groups in the same molecule. Suitable bis(anhydrides) include, for example, pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-diphthalic anhydride, 3,4'-diphthalic anhydride, butane-1,2,3,4-tetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4- Cyclopentanetetracarboxylic acid dianhydride, 1,2,3,4-cyclohexanetetracarboxylic acid dianhydride, 3,3',4,4'-diphenylsulfone-tetracarboxylic acid dianhydride, 4,4'-(4,4'-isopropylidene diphenyloxy) terephthalic anhydride, 2,3,6,7-naphthalenetetracarboxylic acid 2,3:6,7-dianhydride, 4,4'-oxydiphthalic anhydride, 3,4-oxydiphthalic anhydride, and the like, and mixtures thereof. In some aspects, the bis(anhydride) is pyromellitic acid dianhydride. In other aspects, the bis(anhydride) has the formula:

[0031]

[0032] Wherein L is an optional divalent linking group having a structure selected from the following: -O-, -S-, -S(=O)-, -S(=O)2-, -C(=O)-, -C2-, -CH2-, -CH2-CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, -C(Ph)(CH3)- and -CH(Ph)-.

[0033] In some aspects, the phthalimide-containing polyol is a diol having the structure:

[0034]

[0035] wherein m and n each independently have an average value of 1 to 5.

[0036] The amount of the phthalimide-containing polyacid or phthalimide-containing polyol incorporated into the polyester polyol can vary and will depend on other formulation components, indices, performance benefits, cost considerations and other factors. In some aspects, the amount will be based on the amount of the polyester polyol, in the range of 10 wt % to 50 wt %, 12 wt % to 30 wt %, or 15 wt % to 25 wt %.

[0037] In some respects, polyester polyol also comprises the repeating unit of another kind of diacid, diester or acid anhydride that are usually used in producing polyester polyol.These reactants are well-known to those skilled in the art, and comprise for example phthalic anhydride, maleic anhydride, itaconic anhydride, isophthalic acid, terephthalic acid, dimethyl terephthalate, DMT residue, C2-C9 aliphatic diacid (such as succinic acid), glutamic acid, adipic acid, suberic acid, azelaic acid etc. or their combination.In some respects, described another kind of diacid, diester or acid anhydride are phthalic anhydride, terephthalic acid or adipic acid or their combination.

[0038] The polyester polyol has a hydroxyl value in the range of 150 to 800 mg KOH / g, or 180 to 450 mg KOH / g, or 200 to 300 mg KOH / g. The polyester polyol has an acid value in the range of 0.1 to 5 mg KOH / g, or 0.2 to 3 mg KOH / g, or 0.3 to 2 mg KOH / g.

[0039] In some respects, polyester polyol is mixed as blend or as reaction component, and natural oil is such as soybean oil, sunflower oil, safflower oil, rapeseed oil, canola oil, corn oil, coconut oil, tall oil, palm oil, olive oil, vegetable oil, linseed oil, castor oil etc.The amount of the natural oil mixed in polyester polyol can change according to expected application.In some respects, the amount of natural oil in use will be based on the amount of polyester polyol, in the scope of 2 % by weight to 20 % by weight or 4 % by weight to 15 % by weight or 5 % by weight to 10 % by weight.

[0040] In some respects, before using polyol to produce rigid foam, polyester polyol is blended with nonionic surfactant. Suitable nonionic surfactant is known in the art and is commercially available. Example includes alcohol alkoxylate, alkanolamide, ethoxylated alkanolamide, EO / PO copolymer, alkoxylated alkylphenol, ethoxylated fatty amine, fatty diester of polyalkylene glycol etc. In some respects, based on the amount of blend, the amount of nonionic surfactant when used is in the range of 1 wt % to 20 wt %, 1 wt % to 10 wt % or 1 wt % to 5 wt %.

[0041] 3. water

[0042] The rigid PU and PIR foams produced according to the present invention include water as a reactant. The amount of water used depends on several factors, including the amount of polyisocyanate, the desired index, the nature and amount of the polyester polyol, the catalyst, surfactant and blowing agent used, and other factors. Typically, the amount of water used is in the range of 0.1 wt % to 3 wt %, 0.2 wt % to 1 wt %, or 0.2 wt % to 0.6 wt %, based on the amount of polyester polyol in the rigid foam formulation.

[0043] 4. Surfactants

[0044] Surfactants suitable for use in preparing PU and PIR foams are well known. Examples include commercially available products from Evonik, Dow Chemical, Siltech, Momentive Performance Materials, etc. Thus, suitable surfactants include B Silicone surfactant (Evonik), Silicone surfactants (Siltech), VORASURF TM Surfactant (Dow), Surfactants (Mmentive) and other surfactants. Many suitable surfactants are polysiloxanes or other silicon-based surfactants. Generally speaking, the surfactant should help to produce closed-cell rigid foam.

[0045] 5. catalyst

[0046] Rigid foams are produced in the presence of urethane catalysts, isocyanurate catalysts, or both.

[0047] Catalysts suitable for use include compounds that catalyze the reaction of isocyanate and water ("blowing catalysts") and compounds that catalyze the formation of urethane, urea or isocyanurate bonds ("PU catalysts", "PIR catalysts" or "trimerization catalysts").

[0048] Amine catalysts are typically tertiary amines or alkanolamines and mixtures thereof with diluents (typically glycols such as dipropylene glycol). Examples include bis(2-dimethylaminoethyl) ether, N,N-dimethylaminopropylamine, N,N-dimethylethanolamine, triethylenediamine, benzyldimethylamine, N,N-dimethylcyclohexylamine, N,N,N',N',N"-pentamethyldiethylenetriamine (PMDETA), diethanolamine, N-ethylmorpholine, N,N,N'N'-tetramethylbutanediamine, 1,4-diaza[2.2.2]bicyclooctane, and the like, and combinations thereof. Examples include 5 or 8 (Evonik) and A-1 or A-99 (Momentive).

[0049] Other catalysts include carboxylates (eg, potassium acetate, potassium octoate), organotin compounds (eg, dibutyltin dilaurate, stannous octoate), quaternary ammonium compounds (eg, N-(2-hydroxyethyl)trimethylammonium chloride), and the like, and combinations thereof.

[0050] Suitable catalysts are available from Evonik ( Amine catalysts, Metal catalysts, TMR catalyst, K-15 catalyst and Catalyst), Huntsman( Catalysts), King Industries( Catalyst), Momentive( Catalysts), Galata Chemicals( Organic tin catalyst) etc.

[0051] 6. Foaming agent

[0052] Optionally, one or more blowing agents (other than water) are included. Blowing agents suitable for use are well known and include aliphatic or alicyclic C4-C6 hydrocarbons, water, monocarboxylic and polycarboxylic acids and their salts, tertiary alcohols, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halogenated hydrocarbons, hydrofluoroolefins (HFOs), etc., and mixtures thereof. For further examples of suitable blowing agents, see U.S. Pat. No. 6,359,022, the teachings of which are incorporated herein by reference.

[0053] Pentane blowing agents are preferred, i.e., n-pentane, isopentane, cyclopentane, and mixtures thereof. In some aspects, cyclopentane may be the most effective of the C5 blowing agents used to achieve the desired low temperature R value. However, cyclopentane may be more expensive than n-pentane or isopentane, and may adversely affect the dimensional stability of the foam, so there may be a trade-off in cost and performance. The specific C5 blowing agent (or combination) and the preferred amount used will depend on many factors, including overall cost, desired foam density, characteristics of the foam, processing considerations, and other factors within the discretion of the skilled person.

[0054] 7. Flame retardants

[0055] Optionally, the rigid foam includes one or more flame retardants. Suitable flame retardant additives include solid or liquid compounds containing phosphorus, chlorine, bromine, boron or a combination of these elements. Examples include brominated phthalic acid diols, ammonium polyphosphate, triethyl phosphate, tris(2-chloroisopropyl) phosphate, tetra(2-chloroethyl)ethylene diphosphate, tris(β-chloroethyl) phosphate, tris(2,3-dibromopropyl) phosphate, and the like.

[0056] 8. Other polyols

[0057] In addition to the polyester polyols formed from the phthalimide-containing reactants, the rigid foams optionally incorporate other polyols (polyester polyols, polyether polyols, Mannich polyols), in particular other aromatic polyester polyols.

[0058] Suitable aromatic polyester polyols are well known and many are commercially available. The polyester polyols can be generated from aromatic dicarboxylic acids or derivatives thereof, in particular one or more phthalate-based compounds or compositions (e.g., terephthalic acid, dimethyl terephthalate, DMT residues, phthalic anhydride, isophthalic acid, etc.) and one or more diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propylene glycol, 2-methyl-1,3-propanediol, glycerol, trimethylpropane, etc.), optionally with a certain aliphatic dicarboxylic acid (e.g., adipic acid, succinic acid) content. In a preferred aspect, the aromatic polyester polyol comprises repeating units from phthalic anhydride and diethylene glycol.

[0059] Commercially available aromatic polyester polyols include Trademarks for products acquired from Stepan Corporation, especially PS series products, such as PS-1812, PS-1912, PS-1952, PS-2002, PS-2080, PS-2352, PS-2412, PS-2520, PS-2602, PS-3021, PS-3422, PS-3524, etc. Suitable aromatic polyester polyols can also be purchased from Huntsman ( Polyols), Coim (ISOEXTER TM polyols) and INVISTA( Polyols) are obtained.

[0060] As measured by ASTM E-222, the hydroxyl number of the aromatic polyester polyol is in the range of 150 to 400 mg KOH / g, 160 to 350 mg KOH / g, or in some aspects in the range of 200 to 300 mg KOH / g or 230 to 250 mg KOH / g. In some aspects, the polyol has a number average molecular weight of 280 to 1100 g / mol or 300 to 700 g / mol. The aromatic polyester polyol preferably has an acid value of less than 5 mg KOH / g, or less than 2 mg KOH / g, or less than 1 mg KOH / g. The polyol has a viscosity of less than 25,000 cP at 25°C, less than 10,000 cP at 25°C, or less than 5,000 cP at 25°C. In some aspects, the viscosity is in the range of 100 cP to 10,000 cP at 25 °C or in the range of 500 cP to 5,000 cP at 25 °C.

[0061] Suitable polyester polyols have an average hydroxyl functionality within the range of 2.7 to 8.0. In the presence of hydroxyl and / or amine functional initiators, these polyols are easily synthesized by the ring-opening polymerization of propylene oxide, ethylene oxide, butylene oxide, tetrahydrofuran or their mixture. In some cases, the reaction is catalyzed by alkali (e.g., KOH), transition metal catalysts (e.g., double metal cyanide catalysts), Lewis acids (e.g., BF3 catalysts) and the like. Various glycols, triols and higher functionality initiators can be used alone or in combination, with the condition that the average hydroxyl functionality of the polyols is between 2.7 and 8.0. In some respects, sucrose, sorbitol or another high functionality initiator are used alone or in combination with glycols (e.g., ethylene glycol, diethylene glycol), triols (e.g., glycerol, trimethylolpropane, triethanolamine) or amine initiators (e.g., ethylenediamine) to achieve high target functionality.

[0062] Many suitable polyester polyols are commercially available having an average hydroxyl functionality in the range of 2.7 to 8.0. Examples include Products (e.g. 4030, 4034, 4035, 4050, 4063, 6501, 8162, 8164, 9138, 9181 and 9196) from Carpenter product( GP-700, GP-5015, GSP-280, GSP-355, GSP-520, SP-477, SPA-357, SPA-530, EDAP-770 and EDAP-800), from Dow Chemical product( 270, 280, 370 and 490) and from Huntsman product( S-490, SA-499, SD-361, SD-441, SG-360 and SG-522).

[0063] Mannich polyols may also be used. Suitable Mannich polyols are the reaction products of phenols (typically alkylated phenols), formaldehyde, and alkanolamines, which are typically alkoxylated with ethylene oxide and / or propylene oxide to provide the desired molecular weight and target hydrophilicity / hydrophobicity balance. See, e.g., U.S. Pat. No. 6,495,722. Mannich polyols are available from Huntsman (e.g., R-425-X, R-470X), Carpenter( MX-425, MX-470), Cardolite (GX-9101, GX-9102, NX-9001), and other suppliers.

[0064] In suitable polyol compositions, the polyether or Mannich polyol will have a hydroxyl value in the range of 150 to 800 mg KOH / g. In some aspects, the polyether polyol will have a hydroxyl value in the range of 150 to 550 mg KOH / g, or in the range of 150 to 400 mg KOH / g.

[0065] The polyether or Mannich polyol will have an average hydroxyl functionality in the range of 2.7 to 8.0. In some aspects, the polyether or Mannich polyol will have an average hydroxyl functionality in the range of 3.0 to 7.0 or 4.0 to 7.0.

[0066] 9. Foam properties

[0067] In some aspects, the rigid polyurethane or polyisocyanurate foam produced from the polyester polyol made from the polyacid containing phthalimide or the polyol containing phthalimide will have a relatively low density of less than 2 pounds per cubic foot (pcf), in the range of 1.4 to 1.8 pcf or 1.5 to 1.7 pcf. In other aspects, the rigid polyurethane or polyisocyanurate foam produced from the polyester polyol made from the polyacid containing phthalimide or the polyol containing phthalimide will have a relatively high density in the range of 2 to 3 pcf, or 2.0 to 2.5 pcf, or 2.2 to 2.4 pcf.

[0068] In some aspects, the rigid polyurethane or polyisocyanurate foam produced from the polyester polyol made from the polyacid containing phthalimide or the polyol containing phthalimide has improved thermal stability compared to similar foams prepared using other polyester polyols (i.e., polyester polyols other than polyester polyols made from the polyacid containing phthalimide or the polyol containing phthalimide). Thermal stability can be evaluated using the 15 minute or 1 hour hot plate test described below (see Table 3-Table 5). In some aspects, the improved thermal stability is demonstrated by reducing the mass loss % measured by at least 5% or otherwise reducing 5% to 50% after a 15 minute hot plate test at a temperature in the range of 1000°C to 1200°C.

[0069] In other aspects, the rigid polyurethane or polyisocyanurate foam produced from the polyester polyol made from the polyacid containing phthalimide or the polyol containing phthalimide has improved expansibility compared to similar foams prepared using other polyester polyols (i.e., polyester polyols other than polyester polyols made from the polyacid containing phthalimide or the polyol containing phthalimide). Expansibility can be evaluated using the 15 minute or 1 hour hot plate test described below (see Table 3-Table 5). In some aspects, the improved expansibility is demonstrated by measuring a thickness increase of at least 5% or otherwise an increase of 5% to 50% after a 15 minute hot plate test at a temperature in the range of 1000°C to 1200°C.

[0070] B. Polyester polyols

[0071] In some aspects, the invention includes polyester polyols incorporating phthalimide-containing polyacids or phthalimide-containing polyols. Thus, some inventive polyester polyols comprise repeating units of terephthalic acid, diethylene glycol, and phthalimide-containing polyacids or phthalimide-containing polyols. Phthalimide-containing reactants have been described above in Section A.2.

[0072] The amount of the phthalimide-containing polyacid or phthalimide-containing polyol incorporated into the polyester polyol can vary and will depend on other formulation components, indices, performance benefits, cost considerations and other factors. In some aspects, the amount will be based on the amount of the polyester polyol, in the range of 10 wt % to 50 wt %, 12 wt % to 30 wt %, or 15 wt % to 25 wt %.

[0073] Optionally, the polyol of invention is mixed with natural oil as blend or reaction component.The amount of the natural oil mixed in the polyester polyol can be changed according to expected application.In some respects, polyol comprises the natural oil of 2 wt % to 20 wt % or 4 wt % to 15 wt % or 5 wt % to 10 wt % based on the amount meter of polyester polyol.Suitable natural oil comprises for example soybean oil, sunflower oil, safflower oil, rapeseed oil, canola oil, corn oil, coconut oil, tall oil, palm oil, olive oil, vegetable oil, linseed oil, castor oil etc.

[0074] Optionally, the polyol includes reactants other than terephthalic acid, such as anhydrides, diacids, or diesters (e.g., phthalic anhydride, maleic anhydride, itaconic anhydride, isophthalic acid, terephthalic acid, dimethyl terephthalate, DMT residues, C2-C9 aliphatic diacids (such as succinic acid), glutamic acid, adipic acid, suberic acid, azelaic acid, etc., or combinations thereof).

[0075] Optionally, the polyol includes a diol or a polyol other than diethylene glycol (eg, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, glycerol, trimethylolpropane, etc.).

[0076] In some aspects, the polyester polyol comprises at least 35 wt%, or 40 wt% to 95 wt%, of terephthalic acid repeating units, based on the combined amount of terephthalic acid and any optional anhydrides, diacids, or diesters other than terephthalic acid.

[0077] In some aspects, the polyester polyol comprises at least 55 wt%, or 60 wt% to 90 wt%, of diethylene glycol repeating units, based on the combined amount of diethylene glycol and any optional diols or polyols other than diethylene glycol.

[0078] In some aspects, the phthalimide-containing polyacid used to produce the polyester polyol is the reaction product of trimellitic anhydride and an amino acid. In some aspects, the amino acid is glycine, alanine, phenylalanine, serine or threonine.

[0079] In other aspects, the phthalimide-containing polyacid used to produce the polyester polyol is the reaction product of phthalic anhydride or trimellitic anhydride and an amino acid selected from aspartic acid and glutamic acid.

[0080] In other aspects, the phthalimide-containing polyacid used to produce the polyester polyol is a diacid having the structure:

[0081]

[0082] Where R 1 and R 2 Each is independently hydrogen, alkyl, hydroxyalkyl, haloalkyl or alkoxy, and n has a value of 0 to 4. In other aspects, R 1 and R 2 Each is independently hydrogen, methyl, methoxy or 2-hydroxyethyl. 1 and R 2 are each independently hydrogen or methyl.

[0083] In some respects, the polyol containing phthalimide for producing polyester polyol is the reaction product of aliphatic amino alcohol, diol or polyol and trimellitic anhydride. Suitable aliphatic amino alcohol and diol or polyol are described in the above part A.2.b. In some respects, amino alcohol is ethanolamine or 2-(2-aminoethoxy) ethanol.

[0084] In other aspects, the phthalimide-containing polyol for producing the polyester polyol is the reaction product of a bis(anhydride) and two molar equivalents of an aliphatic amino alcohol. Suitable bis(anhydrides) and aliphatic amino alcohols are described in Section A.2.b above. In some aspects, the bis(anhydride) is pyromellitic dianhydride. In other aspects, the bis(anhydride) has the formula:

[0085]

[0086] Wherein L is an optional divalent linking group having a structure selected from the following: -O-, -S-, -S(=O)-, -S(=O)2-, -C(=O)-, -C2-, -CH2-, -CH2-CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, -C(Ph)(CH3)- and -CH(Ph)-.

[0087] In still other aspects, the phthalimide-containing polyol used to produce the polyester polyol is a diol having the structure:

[0088]

[0089] wherein m and n each independently have an average value of 1 to 5.

[0090] In some aspects, the polyester polyol further comprises repeating units of another diacid, diester, or anhydride commonly used to produce polyester polyols. These reactants are well known to those skilled in the art and have been described above in Section A.2.b.

[0091] The present invention includes blends comprising the inventive polyester polyol described in Part B and 1 to 20 wt %, 1 to 10 wt %, or 1 to 5 wt % of a nonionic surfactant based on the amount of the blend.

[0092] The polyester polyol has a hydroxyl value in the range of 150 to 800 mg KOH / g, or 180 to 450 mg KOH / g, or 200 to 300 mg KOH / g. The polyester polyol has an acid value in the range of 0.1 to 5 mg KOH / g, or 0.2 to 3 mg KOH / g, or 0.3 to 2 mg KOH / g.

[0093] C. method

[0094] In some aspects, the present invention is directed to a method comprising incorporating a polyester polyol comprising repeating units of a phthalimide-containing polyacid, a phthalimide-containing polyol, or a combination thereof into a rigid polyurethane or polyisocyanurate foam in an amount effective to improve the expansion or thermal stability of the foam as compared to similar foams prepared from other polyester polyols (i.e., polyester polyols other than polyester polyols prepared from phthalimide-containing polyacids or phthalimide-containing polyols).

[0095] In some aspects, the improved expansion of the foam is demonstrated by a measured thickness increase of at least 5%, or in some aspects 5% to 50%, after hot plate testing at a temperature in the range of 1000°C to 1200°C for 15 minutes.

[0096] In some aspects, the improved thermal stability of the foam is demonstrated by a reduction of at least 5%, or in some aspects 5% to 50%, in the % mass loss measured after hot plate testing at a temperature in the range of 1000°C to 1200°C for 15 minutes.

[0097] In other aspects, the present invention relates to a method comprising preparing a rigid polyurethane or polyisocyanurate foam. In this method, polyisocyanates, polyester polyols, water and surfactants are reacted in the presence of a urethane catalyst, an isocyanate catalyst or both, optionally in the presence of a blowing agent, and optionally in the presence of a flame retardant. The polyester polyol comprises repeating units of a polyacid containing phthalimide, a polyol containing phthalimide, or a combination thereof. The polyester polyol has a hydroxyl value in the range of 150 to 800 mg KOH / g and an acid value in the range of 0.1 to 5 mg KOH / g.

[0098] The following examples are merely illustrative of the invention and the skilled artisan will recognize many variations that are within the spirit of the invention and scope of the claims.

[0099] Example 1

[0100] Polyester polyols from phthalimide-containing diols (polyol 1)

[0101] A flask equipped with mechanical stirring, a heating mantle, a bag-packed distillation tower, a condenser and a receiver, a temperature controller, and a nitrogen inlet is charged with trimellitic anhydride (353 g) and diethylene glycol (975 g). 2-(2-aminoethoxy)-ethanol (193 g) is slowly added while stirring at room temperature. The addition rate is controlled to maintain the reaction temperature below 80°C. Water is removed to increase the reaction temperature to 170°C to promote the formation of imide. Heating is continued until the theoretical amount of water is collected and the mixture is uniform. Terephthalic acid (463 g) and phthalic anhydride (222 g) are added while stirring, and the mixture is heated to 220°C for 4 hours. The acid value, hydroxyl value, and water content are monitored until the target hydroxyl number is reached. Soybean oil (173 g, 7.5 wt %) is added, and the mixture is heated to 220°C for 8 hours to promote transesterification. The obtained product had a hydroxyl value: 249 mg KOH / g; an acid value: 0.4 mg KOH / g. The product was combined with a nonionic surfactant (5% by weight) and then used as a polyol component for preparing a rigid foam.

[0102] Example 2

[0103] Polyester polyol from phthalimide-containing diol (Polyol 2)

[0104] The procedure of Example 1 was generally followed, using ethanolamine (76 g) instead of 2-(2-aminoethoxy)ethanol. Amounts of other reactants: trimellitic anhydride (238 g); diethylene glycol (1096 g); phthalic anhydride (276 g); terephthalic acid (574 g); soybean oil (176 g). Hydroxyl value: 250 mg KOH / g; acid value: 0.6 mg KOH / g. The product was combined with a nonionic surfactant (5 wt %) before use as the polyol component for the preparation of rigid foam.

[0105] Example 3

[0106] Polyester polyols from phthalimide-containing diacids (Polyol 3)

[0107] The procedure of Example 1 was generally followed, using alanine (90 g) instead of 2-(2-aminoethoxy)ethanol to generate the diacid intermediate containing phthalimide. Amounts of other reactants: trimellitic anhydride (195 g); diethylene glycol (991 g); phthalic anhydride (263 g); terephthalic acid (379 g); soybean oil (150 g). Hydroxyl value: 238 mg KOH / g; acid value: 0.6 mg KOH / g. The product was combined with a nonionic surfactant (5 wt%) before use as the polyol component for the preparation of rigid foam.

[0108] Example 4

[0109] From phthalimide-containing diacids and

[0110] Polyester polyol containing phthalimide diol (polyol 4)

[0111] The procedure of Example 1 was generally followed, using alanine (59 g) and ethanolamine (54 g) to generate a phthalimide-containing diacid intermediate and a phthalimide-containing diol intermediate, respectively. Amounts of other reactants: trimellitic anhydride (296 g), diethylene glycol (938 g), adipic acid (129 g), terephthalic acid (476 g), and soybean oil (150 g). Hydroxyl value: 245 mg KOH / g; acid value: 0.3 mg KOH / g. The product was combined with a nonionic surfactant (5 wt %) before use as the polyol component for the preparation of rigid foam.

[0112] Example 5

[0113] Polyester polyols from phthalimide-containing diacids (polyol 5)

[0114] The procedure of Example 1 was generally followed, using ethanolamine (100 g) instead of 2-(2-aminoethoxy)ethanol to produce a phthalimide-containing diol intermediate. Amounts of other reactants: trimellitic anhydride (169 g); diethylene glycol (938 g); phthalic anhydride (197 g); terephthalic acid (574 g); adipic acid (78 g); soybean oil (150 g). Hydroxyl value: 245 mg KOH / g; acid value: 0.3 mg KOH / g. The product was combined with a nonionic surfactant (5 wt %) before use as a polyol component for the preparation of rigid foams.

[0115] Comparative Example 6

[0116] use PS-2352 (aromatic polyester polyol, hydroxyl number of about 240 mg KOH / g) was used as the polyol component for preparing the rigid foam.

[0117] Comparative Example 7

[0118] An aromatic polyester polyol containing terephthalic acid / phthalic anhydride (65 / 35 molar ratio), diethylene glycol / triethylene glycol (80 / 20 molar ratio) and 7.5 wt% of soybean oil having a nominal hydroxyl value of 250 mg KOH / g was used as the polyol component for the preparation of the rigid foam.

[0119] Comparative Example 8

[0120] use PS-2602 (a modified aromatic polyester polyol based on phthalic anhydride, with a hydroxyl number of about 260 mg KOH / g) was used as the polyol component for the preparation of the rigid foam.

[0121] Example 9

[0122] Polyester polyols from phthalimide-containing diacids (polyol 9)

[0123] A flask equipped with mechanical stirring, a heating mantle, a bag-packed distillation column, a condenser and a receiver, a temperature controller and a nitrogen inlet was charged with phthalic anhydride (497 g), aspartic acid (112 g) and diethylene glycol (719 g). The addition rate was controlled to maintain the reaction temperature below 80° C. The reaction mixture was heated to 220° C. for 10 hours. The acid value, hydroxyl value and water content were monitored until the target hydroxyl number was reached. Soybean oil (113 g) was added, and the mixture was heated to 220° C. for 2 hours to promote transesterification. The resulting product had a hydroxyl value: 249 mg KOH / g; an acid value: 2.7 mg KOH / g. The product was combined with a nonionic surfactant (5% by weight) and then used as a polyol component for preparing a rigid foam.

[0124] Low density rigid PIR foam

[0125] Low density (1.6 pcf) rigid polyisocyanurate foam was prepared. The B-side blend (polyester polyol, flame retardant, catalyst, surfactant, water and blowing agent) is shown in Table 1. Prior to foam preparation, the B-side and 489 (polymeric MDI, Covestro product, index 260) was equilibrated in a 70°F constant temperature bath for 1 hour. The polymeric MDI was weighed into a quart cup. The B-side component was added quickly, the reactants were mixed at >2500 ppm for 6 seconds, and the mixture was poured into a gallon paper cup. The crown was cut at 90 seconds.

[0126] High density rigid PIR foam

[0127] The procedure described above for preparing low density PIR foam was generally followed, with the recipe adjusted to give a good high density (2.3 pcf) PIR foam with an index of 300 (see Table 2 for formulation details).

[0128] Hot Plate Test

[0129] Foam samples were cut into 4"x4"x1.25" and the mass, thickness and density were measured. The samples were placed on a preheated (1200°C) hot plate for 15 minutes, during which the temperature was gradually reduced to 1000°C. High density foam samples were also tested for one hour. The samples were weighed, cut in half to determine the thickness, and analyzed for charring characteristics. The results appear in Tables 3-5.

[0130] Thermal stability measured by thermogravimetric analysis

[0131] Thermogravimetric analysis (TGA) was performed using a Discovery TGA instrument (TA Instruments). Polyol samples (30-40 mg) or PIR foam samples (3-4 mg) were tested in air at 25 mL / min. The temperature was increased from ambient temperature (25°C) to 700°C at 10°C / min. The data were plotted as mass retention (%) versus temperature. Higher mass retention at a given temperature indicates higher thermal stability. The results appear in Tables 6 and 7.

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139] As shown in Table 3, low density (index 260) rigid PIR foams from polyesters made using phthalimide-containing polyols or phthalimide-containing polyacids exhibit better thermal stability (lower mass loss) and much improved expansion (greater thickening) in the 15-minute hot plate test compared to rigid foams made from other aromatic polyester polyols. Similar trends are evident for high density (index 300) rigid PIR foams in the 15-minute (Table 4) or one-hour (Table 5) hot plate tests.

[0140] Table 6 shows the results of thermogravimetric analysis (TGA) of high density (index 300) rigid PIR foams in air. Rigid foams made from polyester polyols incorporating phthalimide-containing polyols or phthalimide-containing polyacids retain a higher proportion of their mass (i.e., have a higher thermal stability) when compared to rigid foams made from other polyester polyols. Table 7 demonstrates that the improved thermal stability of the foams can be attributed, at least in part, to the better thermal stability of the phthalimide-containing polyester polyols. The difference in mass retention at 400°C is particularly instructive.

[0141]

[0142]

[0143]

Claims

1. A rigid polyurethane or polyisocyanurate foam comprising the reaction product of: (a) polyisocyanates; (b) a polyester polyol, said polyester polyol comprising the following repeating units: (i) a polyol containing phthalimide; or (ii) a combination of a phthalimide-containing polyol and a phthalimide-containing polyacid; wherein the phthalimide-containing polyacid is the reaction product of trimellitic anhydride and an amino acid selected from the group consisting of glycine, alanine, phenylalanine, serine, threonine, aspartic acid and glutamic acid; and wherein the phthalimide-containing polyol is a reaction product of an aliphatic amino alcohol or a polyol and trimellitic anhydride; or a reaction product of a bis(anhydride) and two molar equivalents of an aliphatic amino alcohol; The polyester polyol has a hydroxyl value in the range of 150 to 800 mg KOH / g and an acid value in the range of 0.1 to 5 mg KOH / g; (c) water; (d) surfactant; (e) urethane catalysts, isocyanurate catalysts, or both; (f) a blowing agent; and (g) Optionally, a flame retardant.

2. The rigid foam according to claim 1, wherein the polyisocyanate is polymeric MDI.

3. A rigid foam according to claim 1 or claim 2, wherein the amino alcohol is ethanolamine or 2-(2-aminoethoxy)ethanol.

4. A rigid foam according to claim 1 or claim 2, wherein the bis(anhydride) is pyromellitic dianhydride.

5. The rigid foam of claim 1 or claim 2, wherein the bis(anhydride) has the formula: Wherein L is an optional divalent linking group having a structure selected from the group consisting of: -O-, -S-, -S(=O)-, -S(=O)2-, -C(=O)-, -CH2-, -CH2-CH2-, -CH(CH3)-, -C(CH3)2-, -C(CF3)2-, -C(Ph)(CH3)- and -CH(Ph)-.

6. The rigid foam according to claim 1 or claim 2, wherein the phthalimide-containing polyol is a diol having the following structure: wherein m and n each independently have an average value of 1 to 5.

7. The rigid foam according to claim 1 or claim 2, wherein the amount of the phthalimide-containing polyacid or the phthalimide-containing polyol incorporated into the polyester polyol is in the range of 10% to 50% by weight based on the amount of the polyester polyol.

8. The rigid foam of claim 1 or claim 2, wherein the polyester polyol further comprises repeating units of one or more reactants selected from the group consisting of phthalic anhydride, maleic anhydride, itaconic anhydride, isophthalic acid, dimethyl terephthalate, succinic acid, glutamic acid, adipic acid, suberic acid, azelaic acid, and combinations thereof.

9. The rigid foam of claim 1 or claim 2, wherein the polyester polyol further comprises repeating units of diethylene glycol.

10. A rigid foam according to claim 1 or claim 2, which has improved expansion compared to similar foams prepared from other polyester polyols, as shown by the following: o C to 1200 o This is demonstrated by a measured thickness increase of at least 5% after a 15 minute hot plate test at a temperature in the range of C.

11. The rigid foam of claim 1 or claim 2, which has improved thermal stability compared to similar foams made from other polyester polyols, as determined by o C to 1200 o A reduction of at least 5% in % mass loss after hot plate testing for 15 minutes at temperatures within a range of C is demonstrated.

12. The rigid foam according to claim 10, wherein the blowing agent is a pentane blowing agent selected from n-pentane, isopentane, cyclopentane or a mixture thereof.

13. The rigid foam according to claim 11, wherein the blowing agent is a pentane blowing agent selected from n-pentane, isopentane, cyclopentane or a mixture thereof.

14. A method comprising incorporating into a rigid polyurethane or polyisocyanurate foam a polyester polyol comprising repeating units of a phthalimide-containing polyol or a combination of a phthalimide-containing polyol and a phthalimide-containing polyacid in an amount effective to improve the expansion or thermal stability of the foam as compared to similar foams prepared from other polyester polyols; wherein the phthalimide-containing polyacid is the reaction product of trimellitic anhydride and an amino acid selected from the group consisting of glycine, alanine, phenylalanine, serine, threonine, aspartic acid and glutamic acid; and wherein the phthalimide-containing polyol is a reaction product of an aliphatic amino alcohol or a polyol and trimellitic anhydride; or a reaction product of a bis(anhydride) and two molar equivalents of an aliphatic amino alcohol; The polyester polyol has a hydroxyl value in the range of 150 to 800 mg KOH / g and an acid value in the range of 0.1 to 5 mg KOH / g.

15. The method of claim 14, wherein the improved expansion of the foam is achieved by o C to 1200 o This is demonstrated by a measured thickness increase of at least 5% after a 15 minute hot plate test at a temperature in the range of C.

16. The method of claim 14 or claim 15, wherein the improved thermal stability of the foam is achieved by o C to 1200 o A reduction of at least 5% in % mass loss after hot plate testing for 15 minutes at temperatures within a range of C is demonstrated.

17. A method comprising formulating a rigid polyurethane or polyisocyanurate foam by reacting: (a) polyisocyanates; (b) a polyester polyol, said polyester polyol comprising the following repeating units: (i) a polyol containing phthalimide; or (ii) a combination of a phthalimide-containing polyol and a phthalimide-containing polyacid; wherein the phthalimide-containing polyacid is the reaction product of trimellitic anhydride and an amino acid selected from the group consisting of glycine, alanine, phenylalanine, serine, threonine, aspartic acid and glutamic acid; and wherein the phthalimide-containing polyol is a reaction product of an aliphatic amino alcohol or a polyol and trimellitic anhydride; or a reaction product of a bis(anhydride) and two molar equivalents of an aliphatic amino alcohol; The polyester polyol has a hydroxyl value in the range of 150 to 800 mg KOH / g and an acid value in the range of 0.1 to 5 mg KOH / g; (c) water; (d) surfactant; (e) urethane catalysts, isocyanurate catalysts, or both; (f) a blowing agent; and (g) Optionally, a flame retardant.

18. The method according to claim 17, wherein the blowing agent is a pentane blowing agent selected from n-pentane, isopentane, cyclopentane or a mixture thereof.

19. The method of claim 18, wherein the rigid polyurethane or polyisocyanurate foam has improved expansion compared to similar foams prepared from other polyester polyols, as determined by o C to 1200 o This is demonstrated by a measured thickness increase of at least 5% after a 15 minute hot plate test at a temperature in the range of C.

20. The method of claim 18, wherein the rigid polyurethane or polyisocyanurate foam has improved thermal stability compared to similar foams prepared from other polyester polyols, as determined by o C to 1200 o A reduction of at least 5% in % mass loss after hot plate testing for 15 minutes at temperatures within a range of C is demonstrated.

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