Polyester polyol and method for preparing same

Abstract

The present invention relates to polyester polyols derived from a reaction mixture comprising at least one anhydrohexitol, at least one polyfunctional carboxylic acid, and at least one non-metallic inorganic acidic catalyst selected from non-metallic inorganic acidic compounds having a phosphorus atom in an oxidation state of +1, non-metallic inorganic acidic compounds having a phosphorus atom in an oxidation state of +3, and mixtures thereof. Additionally, the present invention relates to a method for making the polyester polyols and their use in polyurethane adhesive compositions.

Description

[Technical field]

[0001] The present invention relates to polyester polyols, particularly bio-based polyester polyols, and to methods for their preparation. Additionally, the present invention relates to polyurethane adhesive compositions comprising the polyester polyols. [Background technology]

[0002] Polyester polyol is one of the raw materials for producing polyurethane, and is usually a linear polymer obtained by condensation polymerization of multifunctional carboxylic acids and polyols. Condensation polymerization is a reversible reaction, but as the viscosity of the reaction mixture increases in the later stage of the reaction, the reaction product water cannot be easily separated from the reaction mixture. Therefore, it is necessary to maintain the forward reaction direction by methods such as heating and increasing the stirring speed. However, if the reaction time is too long, the cost will increase and the properties of the polyester polyol may deteriorate. In order to shorten the reaction time, catalysts suitable for the condensation polymerization of polyester polyols have been widely used.

[0003] Meanwhile, renewable bio-based resources have also been successfully developed, and various bio-based polyols, such as coconut oil, natural rubber, rubber seed oil, cashew nut / shell oil, soybean oil, and isosorbide, have been adopted for polyester polyols.

[0004] Isosorbide, among others, can be produced by catalytic dehydration of sorbitol, a hydrogenated product of glucose that is widely biorenewable. Isosorbide, a typical bio-based chemical, has many unique properties, such as a rigid structure of V-shaped diol molecule, high thermal stability, biodegradability, renewable potential, solubility in water, and non-toxicity, which may provide many features to polymer materials using isosorbide as a monomer. Recently, isosorbide has been used to prepare polyester polyols for polyurethane adhesives.

[0005] For example, U.S. Patent Application Publication No. 2013 / 0109804 discloses a polycarbonate diol obtained by reacting at least one diol selected from isosorbide, isomannide, and isoidide, a diol having 1 to 15 carbon atoms that may contain a heteroatom, and (iii) a diester carbonate, using a metal catalyst as a transesterification catalyst.

[0006] US Pat. No. 9,309,438 discloses a radiation-curable composition comprising at least one (meth)acrylated compound (A); and at least one inactive OH-terminated polyester (B) prepared from a polyol component comprising at least one cyclic ether polyol and a polyacid component using a strong acid such as an alkyl- and / or arylsulfonic acid or an organometallic compound as a catalyst.

[0007] US Patent Publication No. 2009 / 0253888 discloses a method for preparing polyesters using an organophosphinic acid compound as a catalyst in combination with a metal catalyst.

[0008] However, due to the reactivity of isosorbide, it has been found that when polyester polyols containing a large amount of isosorbide are polymerized by conventional methods, the reaction product appears dark in color, which indicates that isosorbide is affected by side effects in the presence of conventional catalysts during polymerization.Therefore, it is desirable to produce polyester polyols containing high isosorbide content with high conversion using cost-effective catalysts. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] US Patent Application Publication No. 2013 / 0109804 [Patent Document 2] U.S. Pat. No. 9,309,438 [Patent Document 3] US Patent Application Publication No. 2009 / 0253888 Summary of the Invention

[0010] The first object of the present invention is to at least one anhydrohexitol, at least one multifunctional carboxylic acid, and At least one non-metallic inorganic acidic catalyst selected from non-metallic inorganic acidic compounds having a phosphorus atom in the oxidation state +1, non-metallic inorganic acidic compounds having a phosphorus atom in the oxidation state +3, and mixtures thereof. and providing a polyester polyol derived from a reaction mixture comprising:

[0011] Another object of the present invention is to provide a polyurethane adhesive composition comprising a polyol component comprising at least one polyester polyol of the present invention and an isocyanate component comprising at least one multifunctional isocyanate.

[0012] It is yet another object of the present invention to provide a polyurethane adhesive composition comprising a prepolymer that is the reaction product of a polyol component comprising at least one polyester polyol of the present invention and an isocyanate component comprising at least one multifunctional isocyanate.

[0013] It is yet another object of the present invention to provide one-part, two-part or multi-part adhesive systems comprising the reactive adhesive composition of the present invention.

[0014] It is yet another object of the present invention to provide a method of bonding materials which involves applying the one-part, two-part or multi-part adhesive system of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] In the following passages, the present invention will be described in more detail. Each aspect so described can be combined with any other aspect or aspects, unless expressly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous can be combined with any other feature or features indicated as being preferred or advantageous.

[0016] Unless otherwise defined, all terms used in disclosing the present invention, including technical and scientific terms, have the meaning commonly understood by one of ordinary skill in the art to which this invention belongs. Definitions of terms are set forth with further guidance to better understand the teachings of the present invention.

[0017] As used herein, the singular forms "a," "an," and "the" include both singular and plural referents unless the context clearly dictates otherwise.

[0018] The terms "comprising," "comprises," and "comprised of," as used herein, are synonymous with "including," "includes," or "containing," "contains," and are inclusive or open-ended and do not exclude additional, unrecited members, elements, or process steps.

[0019] The term "bio-based" refers to a material or product that is at least partially derived from biomass, such as plants, trees, animals, etc., and may have been subjected to physical, chemical, or biological processing. The term "fully bio-based" refers to a material or product that is entirely derived from biomass, such as plants, trees, animals, etc., and may have been subjected to physical, chemical, or biological processing.

[0020] The recitation of numerical endpoints includes all values ​​and fractions subsumed within the respective ranges, as well as the recited endpoints.

[0021] All documents cited herein are incorporated by reference in their entirety.

[0022] When referring to the molecular weight of a polymer herein, unless otherwise specified, the reference refers to the average molecular weight M n The number average molecular weight M of a polymer n can be determined, for example, by gel permeation chromatography (GPC) using THF as an eluent. Unless otherwise specified, the molecular weight is determined by GPC calibrated with polystyrene standards. The average molecular weight M w Also, M n This can be determined by GPC as described above.

[0023] The disclosed polyester polyols are derived / obtained from a reaction mixture comprising at least one anhydrohexitol, at least one multifunctional carboxylic acid, and at least one non-metallic inorganic acidic catalyst selected from non-metallic inorganic acidic compounds having a phosphorus atom in an oxidation state of +1, non-metallic inorganic acidic compounds having a phosphorus atom in an oxidation state of +3, and mixtures thereof.

[0024] Anhydrohexitols are obtained by dehydration of hexitols such as sorbitol (glucitol), mannitol, and iditol, which are in turn produced by reducing the carbonyl group of hexoses such as glucose, mannose, and idose, which are usually derived from several biological sources such as wheat, corn, and cellulose.

[0025] Double dehydration produces dianhydrohexitols. Typically, the anhydrohexitols are dianhydrohexitols such as dianhydromannitol, dianhydrosorbitol, dianhydroiditol and mixtures thereof. The dianhydrohexitols are preferably dianhydrosorbitols such as isosorbide, isomannide, isoidide, and more specifically isosorbide. Several companies specialize in the production of isosorbide, isomannide, and isoidide.

[0026] Preferably, the amount of the at least one anhydrohexitol is from 20 mol % to 60 mol %, based on the total moles of the polyester polyol reactants.

[0027] In addition to the anhydroxyhexitols, the polyester polyol reactants may optionally include at least one polyol other than the anhydrohexitols to react with the polyfunctional carboxylic acid.

[0028] Examples of such polyols include monoethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol (including R-, S- and racemic forms), 1,4-butanediol, 1,4-pentanediol, 3-methylpentane-1,5-diol, neopentyl glycol (2,2-dimethyl-1,3-propanediol), 1,5-pentanediol, 1,6-hexanediol, 1,8-ethane glycol, cyclohexanedimethanol, 2-methylpropane-1,3-diol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol and polybutylene glycol.

[0029] Preferably, the polyols other than the anhydrohexitols are fully bio-based. Examples of such polyols include, but are not limited to, glycerol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol (including R-, S- and racemic forms), 1,4-butanediol, 1,4-pentanediol, 1,5-pentanediol, ethylene glycol, diethylene glycol and triethylene glycol. These polyols may be used alone or in combination.

[0030] In one embodiment, the polyester polyol reactants include at least one polyol other than anhydrohexitol. If present, the amount of polyol other than anhydrohexitol is from 1 mol % to 35 mol % based on the total moles of the polyester polyol reactants.

[0031] In another embodiment, the polyester polyol reactants include only anhydrohexitols as a polyol source for preparing the polyester polyols of the present invention.

[0032] The polyester polyols can be prepared by polycondensation of anhydrohexitols, optionally at least one polyol other than anhydrohexitols, and a substoichiometric amount of a polyfunctional carboxylic acid in the presence of the catalyst of the present invention. Preferably, the polyfunctional carboxylic acid (e.g., dicarboxylic acid and / or tricarboxylic acid) or reactive derivatives thereof (e.g., carboxylic anhydrides, chlorides, esters) have 2 to 36 carbon atoms.

[0033] Examples of dicarboxylic acids include adipic acid, succinic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, itaconic acid, furandicarboxylic acid, isophthalic acid, terephthalic acid, orthophthalic acid, dimerized fatty acid, trimerized fatty acid, and the like. These dicarboxylic acids are used alone or in combination. Examples of carboxylic anhydrides include adipic anhydride, succinic anhydride, and the like. These dicarboxylic anhydrides are used alone or in combination. In one embodiment, the polyfunctional carboxylic acid is selected from succinic acid, azelaic acid, sebacic acid, dimerized fatty acid, trimerized fatty acid, and mixtures thereof.

[0034] Dimerized fatty acids are the dimerization products of mono- or polyunsaturated acids and / or their esters. Preferred dimerized fatty acids are dimers of C10- to C36-, more preferably C12- to C24-, especially C14- to C22-alkyl chains. Suitable dimerized fatty acids include the dimerization products of oleic acid, linoleic acid, linolenic acid, palmitoleic acid, elaidic acid. Dimerization products of unsaturated fatty acid mixtures obtained by hydrolysis of natural fats and oils, such as sunflower oil, soybean oil, olive oil, rapeseed oil, cottonseed oil and tall oil, can also be used. Examples of dimerized (dimeric) fatty acids are Pripol 1019, 1013, 1017, 1006, available from Croda.

[0035] According to the present invention, the amount of the at least one polyfunctional carboxylic acid is up to 50 mol %, preferably 40-50 mol %, based on the total moles of the polyester polyol reactants.

[0036] The polycondensation of anhydrohexitol, any polyol and polyfunctional carboxylic acid is carried out in the presence of at least one catalyst.The catalyst is a non-metallic inorganic acidic catalyst, and is selected from non-metallic inorganic acidic compounds having phosphorus atom in oxidation state +1, non-metallic inorganic acidic compounds having phosphorus atom in oxidation state +3, and mixtures thereof.In a preferred embodiment, the at least one non-metallic inorganic acidic catalyst is selected from phosphinic acid, phosphonic acid, and mixtures thereof.In a further preferred embodiment, the non-metallic inorganic acidic catalyst is phosphinic acid.

[0037] The reaction mixture for preparing the polyester polyol can further include at least one solvent, such as water. When present, the solvent is included in an amount of 0.01 to 1 wt %, more specifically 0.1 to 0.5 wt %, of the total weight of the reactants. The non-metallic inorganic acidic catalyst can first be dissolved in water in a weight ratio of 5:1 to 1:5, preferably 1:1, and mixed with the other reactants to form the reaction mixture.

[0038] The inventors have surprisingly found that the non-metallic inorganic acidic catalyst of the present invention can prevent the decomposition of anhydrohexitol during polycondensation reaction at high temperatures, for example in localized areas of a polymerization reactor, and can reduce the cost of large-scale production of such polyester polyols compared to the much more expensive metal catalysts and organophosphoric acid catalysts used in the past. Furthermore, the use of the non-metallic inorganic acidic catalyst of the present invention does not produce harmful by-products that do not comply with chemical registrations and regulations in the production of anhydrohexitol-based polyester polyols. Thus, the cost and technical challenges of producing polyester polyols with high isosorbide content using organophosphorus compounds can be overcome, such as desired product specifications, bright product color, shorter reaction times, and fewer side reactions.

[0039] Preferably, the amount of non-metallic inorganic acidic catalyst used in the polycondensation reaction ranges from 0.001 to 5% by weight, more specifically from 0.02 to 1% by weight, of the total weight of the reactants.

[0040] Furthermore, the polyester polyol reaction mixture is essentially free of other catalysts, such as organic phosphoric acid, metal catalysts, amine catalysts or inorganic phosphoric acid with phosphorus atom in oxidation state +5. Preferably, it contains less than 0.05 wt. %, in particular less than 0.02 wt. %, of such catalysts based on the total weight of the reaction mixture. In a preferred embodiment, the polyester polyol reaction mixture is free of other catalysts.

[0041] Examples of metal catalysts include aluminum alkoxides, titanium alkoxides, magnesium alkoxides and zirconium alkoxides, tin compounds, more specifically organotin carboxylates such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin bis-(2-ethylhexanoate) or other organotin compounds such as dibutyltin oxide, dibutyltin dimethoxide, dibutyltin dibromide, dibutyltin dichloride, di-tert-butyltin dichloride, dimethyltin dibromide, dimethyltin dichloride, diphenyltin dichloride, or tin octoate, iron acetate, iron benzoate, iron naphthenate; iron acetylacetonate, manganese acetate, manganese naphthenate, manganese acetylacetonate, and the like.

[0042] In accordance with the present invention, polyester polyols containing higher amounts of anhydrohexitol building blocks are preferably prepared by a process comprising the steps of: (1) providing a reaction mixture comprising at least one anhydrohexitol, at least one polyfunctional carboxylic acid, at least one non-metallic inorganic acidic catalyst, and optionally at least one linear or branched aliphatic polyol to form a mixture; (2) heating the mixture stepwise to 200° C.-220° C. and maintaining it under nitrogen flow for 20-40 hours; (3) reducing the pressure stepwise to 1-300 mbar to complete the reaction; and (4) cooling the reaction mixture when the acid value of the reaction mixture is 5 or less to obtain a polyester polyol.

[0043] In the present invention, there is no particular limitation on the physical properties of the polyester polyol prepared by the above-mentioned method. Preferably, the polyester polyol is completely bio-based and is in the form of an amorphous liquid, a crystalline solid or an amorphous solid at room temperature.

[0044] In general, there is no particular restriction on the molecular weight of the polyester polyol used in the adhesive composition, so long as it does not adversely affect the properties of the adhesive composition and the cured adhesive. Preferably, the polyester polyol has a molecular weight M of 500 to 20,000 g / mol, particularly 1,000 to 10,000 g / mol.n has.

[0045] In the present invention, the polyester polyol preferably has an acid value of 0.1 to 5, more preferably 1 to 3 mgKOH / g. Assuming that all acid groups contained in 1 g of resin are free acids, the "acid value" of the polyester polyol of the present invention is expressed as the calculated value of the number of milligrams of potassium hydroxide required to neutralize the acid. Therefore, even if the acid group exists as a base in an actual system, it is regarded as a free acid. The "acid value" of the present invention is determined by dissolving the polyester polyol in a solvent, adding phenolphthalein as an indicator, and titrating with a 0.1 mol / L potassium hydroxide-ethanol solution in accordance with DIN 51558.

[0046] In the present invention, the polyester polyol may have a hydroxyl value of 5 to 150 mg KOH / g, preferably 10 to 120 mg KOH / g, particularly 15 to 100 mg KOH / g. As used herein, the hydroxyl value refers to the number of milligrams of potassium hydroxide required to neutralize acetic acid bound to the hydroxyl groups when 1 g of resin is acetylated.

[0047] The "hydroxyl number" of the present invention is determined in accordance with DIN 51558 by adding an acetylating agent to a polyester polyol, heating with a glycerin solution, cooling, adding phenolphthalein as an indicator, and titrating with a potassium hydroxide-ethanol solution.

[0048] In the present invention, the polyester polyol may have a glass transition temperature of -100°C to 100°C. The glass transition temperature of the polyester polyol is measured using a differential scanning calorimeter. A DSC curve was measured for an appropriate amount of sample at a heating rate of 10°C / min by differential scanning calorimetry, and the temperature of the inflection point of the obtained DSC curve was regarded as the glass transition temperature.

[0049] In one embodiment, the polyester polyol, preferably the fully bio-based polyester polyol, is an amorphous liquid. Preferably, such polyester polyol has an acid value of 0.1 to 3 mg KOH / g. Preferably, such polyester polyol has a hydroxyl value of 30 to 120 mg KOH / g, more preferably 50 to 100 mg KOH / g. Preferably, such polyester polyol has a Tg of -70 to -20°C, more preferably -30 to -60°C.

[0050] In another embodiment, the polyester polyol, preferably the fully bio-based polyester polyol, is a crystalline solid. Preferably, such polyester polyol has an acid value of 0.1-3 mgKOH / g. Preferably, such polyester polyol has a hydroxyl value of 20-100 mgKOH / g, more preferably 30-60 mgKOH / g. Preferably, such polyester polyol has a melting point of 30-100°C, preferably 40-70°C.

[0051] In yet another embodiment, the polyester polyol, preferably a fully biologically derived polyester polyol, is an amorphous solid. Preferably, such polyester polyol has an acid value of 0.1-3 mg KOH / g. Preferably, such polyester polyol has a hydroxyl value of 20-100 mg KOH / g, more preferably 30-80 mg KOH / g. Preferably, such polyester polyol has a Tg of -15-80°C, more preferably -10-60°C.

[0052] Another object of the present invention is to provide a reactive adhesive composition comprising a polyol component comprising at least one polyester polyol of the present invention and an isocyanate component comprising at least one multifunctional isocyanate.

[0053] According to the present invention, the reactive adhesive composition comprises the polyester polyol in an amount of 5% to 80% by weight, preferably 10% to 50% by weight, based on the total weight of the reactive adhesive composition.

[0054] It is yet another object of the present invention to provide a polyurethane adhesive composition comprising a prepolymer that is a reaction product obtained from a reaction mixture comprising a polyol component comprising at least one polyester polyol of the present invention and an isocyanate component comprising at least one multifunctional isocyanate.

[0055] According to the present invention, the prepolymer reactants include polyester polyol in an amount of 5% to 80% by weight, preferably 10% to 50% by weight, based on the total weight of the reactants.

[0056] Polyfunctional isocyanates that can be used in the practice of the present invention include alkylene diisocyanates, cycloalkylene diisocyanates, aromatic diisocyanates, and aliphatic-aromatic diisocyanates. Specific examples of suitable isocyanate-containing compounds include ethylene diisocyanate, ethylidene diisocyanate, propylene diisocyanate, butylene diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, cyclopentylene-1,3-diisocyanate, cyclohexylene-1,4-diisocyanate, cyclohexylene-1,2-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2-diphenylpropane-4,4'-diisocyanate, xylylene diisocyanate, 1,4-naphthylene diisocyanate, 1,5-naphthylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, diphenyl 4,4'-diisocyanate, azobenzene 4,4'-diisocyanate, These include, but are not limited to, diphenylsulfone-4,4'-diisocyanate, 2,4-tolylene diisocyanate, dichlorohexamethylene diisocyanate, furfurylidene diisocyanate, 1-chlorobenzene-2,4-diisocyanate, 4,4',4"-triisocyanatotriphenylmethane, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 4,4'-dimethyldiphenylmethane-2,2',5,5-tetratetraisocyanate, and the like. While such compounds are commercially available, methods for synthesizing such compounds are well known in the art. Oligomers, such as dimers and trimers, of the above monomeric isocyanates can also be utilized in the present invention. Preferably, the polyfunctional isocyanate is 4,4'-diphenylmethane diisocyanate (MDI).

[0057] Polyfunctional isocyanates also include blocked polyisocyanates such as the reaction products of mono-ol or monohydroxyphenolic compounds with organic polyisocyanates, which include organic compounds containing at least two isocyanato groups, including the hydrocarbon diisocyanates (e.g., alkylene diisocyanates and arylene diisocyanates), as well as the known triisocyanates and polymethylene poly(phenylene isocyanates).

[0058] Illustrative examples of polyisocyanates for use in preparing the blocked isocyanates are: 2,4'-diisocyanatotoluene, 2,6-diisocyanatotoluene, methylenebis(4-cyclohexylisocyanate), 1,2-diisocyanatoethane, 1,3-diisocyanatopropane, 1,2-diisocyanatopropane, 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, bis(3-isocyanatopropyl)ether, bis(3-isocyanatopropyl)sulfide, 1,7-diisocyanatoheptane, 1,5-diisocyanato-2,2-dimethylpentane, 1,6-diisocyanato-3-methoxyhexane, 1,8-diisocyanatooctane, 1,5-diisocyanato-2,2,4-trimethylpentane, 1,9 ...bis(3-isocyanatopropyl)sulfide, bis(3-isocyanatopropyl)sulfide, bis(3-isocyanatopropyl)sulfide, bis(3-isocyanatopropyl)sulfide, bis(3-isocyanatopropyl)sulfide, bis(3-isocyanatopropyl)sulfide, bis(3-iso Natononane, 1,10-diisocyanatopropyl ether of 1,4-butylene glycol, 1,11-diisocyanatoundecane, 1,12-diisocyanatododecane, bis(isocyanatohexyl) sulfide, 1,4-diisocyanatobenzene, 2,4-diisocyanatotrilen, 2,6-diisocyanatotrilen, 1,3-diisocyanato-o-xylene, 1,3-diisocyanato-m-xylene, Silene, 1,3-diisocyanato-p-xylene, 2,4-diisocyanato-l-chlorobenzene, 2,4-diisocyanato-l-nitrobenzene, 2,5-diisocyanato-l-nitrobenzene, 4,4-diphenylmethylene diisocyanate, 3,3-diphenylmethylene diisocyanate, polymethylene poly(phenylene isocyanate), isophorone diisocyanate and mixtures thereof.

[0059] According to the present invention, the reactive adhesive composition or prepolymer reactant comprises a polyfunctional isocyanate in an amount of 5% to 50% by weight, preferably 10% to 30% by weight, based on the total weight of the reactive adhesive composition or reactant.

[0060] The polyol component or prepolymer reactants of the reactive adhesive composition may contain other polymeric polyols to further improve the adhesive properties. These other polymeric polyols may be bio-based or fossil-based. Preferably, these polymeric polyols are also bio-based to increase the biomass content in the adhesive composition. In a preferred embodiment, the polyol component further comprises other bio-based polymeric polyols. In another preferred embodiment, the amount of fully bio-based polyester polyols and other bio-based polymeric polyols (if present) is 50% to 85% by weight based on the total weight of the reactive adhesive composition.

[0061] When present, other polymeric polyols are present in the adhesive composition in an amount of from 1 to 50 weight percent, based on the total weight of the reactive adhesive composition.

[0062] In a preferred embodiment, the molar ratio of the at least one polyfunctional isocyanate to the at least one polyester polyol of the invention and other polymeric polyols, if present, expressed as NCO / OH, is from 5:1 to 1:1, preferably from 2.5:1 to 1.05:1.

[0063] The reactive adhesive composition may contain a catalyst. In the case of a two-part adhesive composition, it may be contained in the isocyanate component or the polyol component. The catalyst is used to promote the crosslinking reaction between the hydroxyl groups and the isocyanate groups of the polyfunctional isocyanate. Examples of catalysts include tertiary amine compounds and organometallic compounds.

[0064] Examples of tertiary amine compounds include triethylamine, triethylenediamine, N,N-dimethylbenzylamine, N-methylmorpholine, and diazabicycloundecene (also known as DBU).

[0065] Examples of organometallic compounds include tin and non-tin compounds.

[0066] Examples of tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (also known as DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, and examples include tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate.

[0067] Examples of non-tin compounds include titanium compounds such as dibutyltitanium dichloride, tetrabutyltitanium trichloride, and butoxytitanium trichloride, lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate, iron compounds such as iron ethylhexanoate and iron 2,4-pentanedionate, cobalt compounds such as cobalt benzoate and cobalt 2-ethylhexanoate, zinc compounds such as zinc naphthenate and zinc 2-ethylhexanoate, and zirconium naphthenate.

[0068] Among these, diazabicycloundecene (DBU), dibutyltin dilaurate (DBTDL), zinc 2-ethylhexanoate, etc. are preferred in terms of reactivity and hygiene.

[0069] The catalysts for the adhesive composition may be used alone or in combination of two or more kinds.

[0070] The adhesive composition of the present invention may or may not contain an organic solvent. Examples of organic solvents include heterocyclic, aliphatic, or aromatic hydrocarbons such as toluene, isophorone, and xylene, monohydric or polyhydric alcohols such as ethylhexanol, butoxypropanol, isopropanol, butyl diglycol, methanol, ethanol, propanol, and butanol, ethers such as diethylene glycol dimethyl ether and dipropylene glycol methyl ether, ethyl glycol, and butyl glycol, esters such as ethyl acetate, butyl acetate, pentyl acetate, or ethyl ethoxypropionate, ketones such as cyclohexanone, methyl ethyl ketone (MEK), methyl amyl ketone, methyl isobutyl ketone (MIBK), and acetone, and amides such as N-methylpyrrolidone, N-ethylpyrrolidone, methoxypropyl acetate, and dimethylformamide.

[0071] The reactive adhesive composition can be used directly as described above, but if desired, the adhesive composition of the present invention can also be formulated with conventional additives that are compatible with the composition. The additives can be included in the polyol and / or isocyanate components, provided that they are inert to other components such as the polyol and / or isocyanate. Such additives include adhesion promoters, defoamers, optical brighteners, dispensing agents, pigments, viscosity modifiers, and mixtures thereof.

[0072] Suitable adhesion promoters for use in the adhesive composition of the present invention are silane compounds such as, for example, mercaptopropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, bis-(γ-trimethoxysilylpropyl)amine, N-β-(aminoethyl)-gamma aminopropylmethyldimethoxysilane, tris-(γ-trimethoxysilyl)isocyanurate and mixtures thereof.

[0073] Suitable antifoam agents for use as additives are, for example, acrylate copolymers.

[0074] An optical brightener suitable for use as an additive is, for example, 2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole).

[0075] Dispensing agents suitable for use are, for example, polymeric alkyloamino amides, hydroxy-functional carboxylic acid esters and structured acrylate copolymers.

[0076] Suitable pigments for use are, for example, pigment pastes and colour pastes.

[0077] A suitable viscosity modifier for use is, for example, fumed silica.

[0078] The adhesive composition / system of the present invention can be produced by mixing the components / parts / prepolymers and optional additives. There is no particular limitation on the mixing method as long as the adhesive of the present invention is obtained. There is also no particular limitation on the order in which the components are mixed. The adhesive composition / system of the present invention can be produced without the need for a special mixing method or special mixing order.

[0079] The invention also provides a method of bonding articles together, comprising applying the adhesive system of the invention in liquid form to a first article, contacting a second article with the system applied to the first article, and subjecting the applied system to conditions that allow the system to cure and bond substrates. The compositions are typically dispensed and stored in liquid or solid form and are stored in the absence of moisture. Also provided are articles of manufacture that include the cured adhesive composition of the invention.

[0080] The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the concept of the present invention. EXAMPLES

[0081] The following materials were used in the examples: Sebacic acid was obtained from Sigma Aldrich. Succinic acid was obtained from Sigma Aldrich. Isosorbide was obtained from Roquette under the trade name Polysorb PA. 1,3-Butanediol was obtained from Godavari Biorefineries. 1,2-Propanediol was obtained from Sigma Aldrich. Ethylene glycol was obtained from Sigma Aldrich. Dimeric fatty acids were obtained from Croda under the trade name Pripol. Phosphinic acids were obtained from Sigma Aldrich. Orthophosphoric acid was obtained from Sigma Aldrich. (2-Methoxyphenyl)phenylphosphinic acid was obtained from Sigma Aldrich. Titanium(IV) isopropylate was obtained from Sigma Aldrich. 2,4'-MDI was obtained from Covestro.

[0082] Preparation of polyester polyols Polyester polyol examples of the present invention (Examples 1 to 6) were prepared according to the formulations in Table 1. Comparative polyester polyols (Comparative Examples 1 to 5) were prepared according to the formulations in Table 2.

[0083] The polyacid and polyol were charged into a 1 or 5 liter 4-neck flask equipped with a nitrogen sparge tube, a thermocouple, an overhead stirrer, and a distillation arm. The mixture was heated stepwise under nitrogen flow up to 220 °C. The complete reaction took about 20 to 40 h depending on the reaction composition (monomers and catalyst). Aqueous catalyst solution in a 1:1 weight ratio was added either at the beginning or directly during the polycondensation reaction. The system pressure was then reduced stepwise to 10 to 300 mbar to achieve complete conversion. The reaction product was cooled when the acid number was below 5 mg KOH / g. The polyester polyols were characterized by acid number (mg KOH / g), OH number (mg KOH / g), viscosity at specific temperature (Pa·s), and Mn (g / mol) according to the GPC method. DSC measurements were performed to determine the Tg and melting temperature Tm (°C) of the final polyester polyols.

[0084] [Table 1]

[0085] [Table 2]

[0086] As can be seen from Tables 1 and 2, the polyester polyols prepared according to the present invention were colorless to light yellow or yellowish in color, whereas the polyester polyols prepared without the present invention were dark or even black in color, indicating that decomposition of isosorbide occurred during the polymerization process. Also, the preparation of the polyester polyol of Comparative Example 5 required 26 hours, including 16 hours under vacuum conditions, whereas the preparation of the polyester polyol of Example 1 required only 21 hours, including 13.5 hours under vacuum conditions.

Claims

1. At least one anhydrohexitol, at least one polyfunctional carboxylic acid, and at least one non-metallic inorganic acidic catalyst selected from non-metallic inorganic acidic compounds having a phosphorus atom in an oxidation state of +1, non-metallic inorganic acidic compounds having a phosphorus atom in an oxidation state of +3, and mixtures thereof A polyester polyol derived from a reaction mixture containing the same.

2. The polyester polyol according to claim 1, wherein the anhydrohexitol is isosorbide.

3. The polyester polyol according to claim 1, wherein the polyfunctional carboxylic acid is bio-based, preferably selected from adipic acid, succinic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, itaconic acid, furandicarboxylic acid, isophthalic acid, terephthalic acid, orthophthalic acid, dimerized fatty acid, trimerized fatty acid, and mixtures thereof.

4. The polyester polyol according to claim 1, wherein the at least one non-metallic inorganic acidic catalyst is selected from phosphinic acid, phosphonic acid, and mixtures thereof.

5. The polyester polyol according to claim 1, wherein the amount of the at least one anhydrohexitol is 20 mol% to 60 mol% based on the total number of moles of the reactants.

6. The polyester polyol according to claim 1, wherein the amount of the at least one polyfunctional carboxylic acid is 60 mol% or less, preferably 20 mol% to 50 mol% based on the total number of moles of the reactants.

7. The polyester polyol according to claim 1, wherein the reaction mixture further contains at least one polyol other than anhydrohexitol, preferably bio-based, more preferably selected from glycerol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,4-pentanediol, 1,5-pentanediol, ethylene glycol, diethylene glycol, triethylene glycol, and mixtures thereof.

8. The polyester polyol according to claim 7, wherein the amount of the at least one polyol other than anhydrohexitol is 1 mol% to 50 mol%, preferably 10 mol% to 40 mol% based on the total number of moles of the reactants.

9. The polyester polyol according to claim 1, wherein the polyester polyol is liquid amorphous, solid crystalline or solid amorphous.

10. The polyester polyol according to claim 1, wherein the reaction mixture essentially does not contain a metal catalyst, preferably containing less than 0.02% by weight of a metal catalyst based on the total weight of the reaction mixture.

11. The polyester polyol according to claim 1, containing a metal element in an amount of less than 0.002% by weight of the polyester polyol, preferably less than 0.001% by weight.

12. 1) A step of providing a reaction mixture containing at least one anhydrohexitol, at least one polyfunctional carboxylic acid, at least one non-metallic inorganic acidic catalyst, and optionally at least one linear or branched aliphatic polyol; 2) A step of gradually heating the reaction mixture to 200°C to 220°C and maintaining it for 20 hours to 40 hours under a nitrogen flow; 3) A step of gradually reducing the pressure to 1 to 300 mbar to complete the reaction and obtaining a reaction product; and 4) A step of cooling the reaction product when the acid value of the reaction product becomes 5 or less to obtain a polyester polyol A method for preparing a polyester polyol according to any one of claims 1 to 11, comprising the steps.

13. A polyurethane adhesive composition comprising a polyol component containing at least one polyester polyol according to any one of claims 1 to 10 and an isocyanate component containing at least one polyfunctional isocyanate.

14. A polyurethane adhesive composition comprising a prepolymer which is a reaction product obtained by a reaction mixture containing a polyol component containing a polyester polyol according to any one of claims 1 to 11 and an isocyanate component containing at least one polyfunctional isocyanate.

15. An article comprising a cured product of the polyurethane adhesive composition according to claim 13.