Polyester polyol composition

Abstract

The present disclosure provides a composition. In an embodiment, the composition includes a reaction product of (1) a polyester polyol having a functionality greater than or equal to 3.0, and an OH number (OHv) less than 300 mg KOH / g. The composition has an initial viscosity. The composition also includes (2) an isocyanate-silane adhesion promoter providing an OH:NCO equivalence ratio greater than 2.5:1. The composition has a final viscosity less than the initial viscosity.

Description

POLYESTER POLYOL COMPOSITIONBACKGROUND

[0001] Formulation design for polyurethane-based products requires skillful usage and dosage of different kinds of raw materials such as: isocyanates, polyols and additives. Isocyanates include monomeric and polymeric NCO terminated backbones and can be further distinguished into aromatic isocyanates and aliphatic isocyanates depending on the starting materials. Polyols are OH terminated backbones which are generally divided into polyether polyols and polyester polyols. Polyols are characterized by functionality (F), OH number (OHv), and viscosity. Additives can refer to a wide variety of raw materials which are mainly used to enhance or modify the properties of polyurethane-based products and can include catalysts, silicones, colorants, adhesion promoters, UV stabilizers, fillers, flame retardants, etc.

[0002] Formulation design for polyurethane-based products typically focuses on blends or prepolymers. A blend is a simple mixture of raw materials while a prepolymer is a reaction product of raw materials which can either be used as a standalone component or as an intermediate for subsequent blends or prepolymers.

[0003] The viscosity of the formulation, and the viscosity of the polyol in particular, can significantly influence the final usability and subsequent application range for a given polyurethane-based product. Consequently, the art recognizes the need for the ability to control (or reduce) the viscosity of polyols, and polyester polyols in particular, used in the formulation of polyurethane-based products.SUMMARY

[0004] The present disclosure provides a composition. In an embodiment, the composition includes a reaction product of (1) a polyester polyol having a functionality greater than or equal to 3.0, and an OH number (OHv) less than 300 mg KOH / g. The composition has an initial viscosity. The composition also includes (2) an isocyanate-silane adhesion promoter providing an OH:NCO equivalence ratio greater than 2.5:1. The composition has a final viscosity less than the initial viscosity.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 is a graph showing viscosity and OHv for polyether polyols.

[0006] FIG. 2 is a graph showing viscosity and OHv for polyester polyols.

[0007] FIG. 3 is a graph showing viscosity and OHv for inventive example 1 and inventive example 2.DEFINITIONS

[0008] The numerical ranges disclosed herein include all values from, and including, the lower and upper value. For ranges containing explicit values (e.g., a range from 1, or 2, or 3 to 5, or 6, or 7), any subrange between any two explicit values is included (e.g., the range 1-7 above includes subranges 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6; etc.)

[0009] Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percents are based on weight and all test methods are current as of the filing date of this disclosure.

[0010] The terms "comprising", "including", "having" and their derivatives do not exclude the presence of any additional component or procedure. The term, "consisting essentially of" excludes any other component or procedure, except those essential to operability. The term "consisting of" excludes any component or procedure not specifically stated.

[0011] A "hydrocarbon," or a "hydrocarbon group" is a group that consists of only carbon atoms and hydrogen atoms.

[0012] A "polyester" is a compound containing two or more ester linkages in the same linear chain of atoms.

[0013] A "polyether" is a compound containing two or more ether linkages in the same linear chain of atoms.

[0014] A "polyisocyanate," as used herein, is a compound that contains two or more isocyanate groups. An "isocyanate group" is a functional group with the structure: -N=C=O (or "NCO group" or "NCO").

[0015] A "polyol" is an organic compound containing multiple hydroxyl ("—OH," or "OH") groups. In other words, a polyol contains at least two hydroxyl groups. Nonlimiting examples ofsuitable polyols include diols (which contain two hydroxyl groups) and triols (which contain three hydroxyl groups)

[0016] A "polyurethane," as used herein, is the reaction product of an isocyanate with a polyol.TEST METHODS

[0017] Functionality (F). As used herein, "functionality" refers to the number of reactive sites per molecule. For a polyol, the functionality (the number of OH sites per molecule) may be determined by the OH Number and the polyol molecular weight using Equation A below:Equation AFunctionality (F) = OH Number*Molecular Weight / 56100

[0018] OH number. The term "hydroxyl number" (or "OH number") is a measure of the amount of reactive hydroxyl groups available for reaction. The measurements were carried out using a Metrohm Omnis titrator. In a typical measurement a sample is weighted according to the formula 40 / expected OHv ("hereafter "formula") and then dissolved in 30 ml of anhydrous tetrahydrofuran. The sample is then fed to the titrator which performs the measurement through an automated procedure which involves reacting the available OH groups with p-toluenesulfonyl isocyanate to form an acid carbamate, converting the excess of p-toluenesulfonyl isocyanate to sulfonamide with water effectively neutralizing it and finally running a direct potentiometric titration of the acid carbamate with tetrabutylammonium hydroxide. When measuring the OH Number with the formula method, an expectation of what the final result will be is used to calculate the sample weight in grams. By way of example, if the polyol is expected to have an OH number of 50, the sample weight is calculated as follows: Sample Weight = 40 / 50 = 0.8 g.

[0019] Viscosity. Viscosity measurements were performed using a Brookfield DV-I viscosimeter. A measurement sample is conditioned at the desired temperature (25°C, 50°C, or 60°C) for two hours using either a thermostatic bath for measurements at temperatures between 15°C and 25°C or an oven for measurements at temperatures above 25°C. An appropriate spindle is selected according to the expected sample's viscosity range at the desired measurementtemperature. After conditioning, the sample is placed under the viscosimeter and lifted with a support so that the instrument's spindle is submerged in the sample. The spindle is then put under rotation and the rotational speed is adjusted so that the resulting torque is between 40% and 90%. The sample is then left for a few seconds while the viscosity measurement stabilizes after which the value is recorded in centipoise ("cP").DETAILED DESCRIPTION

[0020] The present disclosure provides a composition. In an embodiment, the composition includes a reaction product of (1) a polyester polyol having a functionality greater than or equal to 3.0, and an OH number (OHv) less than 300 mg KOH / g. The polyester polyol has an initial viscosity. The composition also includes (2) an isocyanate-silane adhesion promoter providing an OH:NCO equivalence ratio greater than 2.5:1. The composition has a final viscosity less than the initial viscosity (of the polyester polyol).

[0021] In the design of polyurethane-based products, polyols are typically selected from polyether polyols and polyester polyols depending on their funcionality and molecular weight (MW) for application-specific requirements. In polyols, hydroxyl number (OHv), functionality (F), and molecular weight (MW), having the following correlation:OHv = 56100 * F / MWWhat is evident from this correlation is that for a given F value, the higher the MW the lower the OHv and vice versa. The selection of polyol used in a given formulation has a significant impact in the overall final viscosity of the final composition. This is because a polyol's viscosity is related to its MW principally and this correlation is different when considering polyethers or polyesters.

[0022] Polyethers are made from a starting molecule, typically selected from polyalcohols, polyaminoalcohols and polyalkanolamines, which can be propoxylated or ethoxylated.

[0023] For a given starting material, high molecular weight polyether polyol exhibits high viscosity and as molecular weight decreases so does viscosity. Interestingly, as MW continues to decrease, viscosity will begin to increase at a certain point due to increased hydrogen bondingeffect. A polyether polyol's viscosity is therefore mainly influenced by MW and hydrogen bonding and is shown in the graph in FIG. 1.

[0024] This relationship between viscosity and molecular weight is valid for both ethoxylated polyether and propoxylated polyether. Ethoxylated polyether is typically less viscous than propoxylated polyether at equal OHv and starting molecule. In general, polyether polyols tend to have manageable viscosities compared to polyester polyols and therefore polyether polyols generally do not generate particular issues in formulation design as do polyester polyols.

[0025] Polyester polyols are typically made by condensation of polyalcohols with polycarboxylic acids and / or anhydrides and can be classified into aromatic polyesters and aliphatic polyesters depending on the presence (or absence) of aromatic monomers in the backbone chain. A polyester polyol's viscosity generally increases as MW increases and is mainly affected by MW and the interactions that develop between ester groups. Aromatic polyester polyols exhibit higher viscosities than aliphatic polyester polyols at equal MW. Furthermore, for polyester polyols, the higher the F, the higher the viscosity at a given MW. A plot of a polyester's viscosity is shown in the graph at FIG. 2.

[0026] As shown in FIG. 2, the viscosity increase at low OHv is large, especially for aromatic polyester polyols with F>2. This means that not only is it difficult to design low OHv polyesters but also that, different from polyethers, the choice of polyesters in formulation design is generally restricted to OHv>250 mgKOH / g.

[0027] When considering polyester polyols in polyurethane formulation design, a restriction exists in terms of usable OHv. The correlation between OHv, and viscosity is such that any attempt in synthesizing a low OHv polyester, either via direct monomer condensation or via prepolymerization with isocyanates, will yield an unusable product unless solvents are employed to reduce viscosity. Using a solvent, however, restricts the application field of low OHv polyesters to solvent-based formulations only. In other words, using low OHv polyesters in solvent-free formulations is significantly restricted, let alone impossible, unless an alternative solution is found to break free from the correlation between OHv and viscosity.

[0028] In the present composition, the reaction product includes a polyester polyol having a functionality (F) greater than or equal to 3.0, an OH number (OHv) less than 300 mg KOH / g, andan initial viscosity. The polyester polyol has a functionality greater than or equal to 3.0, or from 3.0 to 10, or from 3.0 to 8.0. The polyester polyol has an OHv number less than 300 mg KOH / g, or from 50 mg KOH / g to less than 300 mg KOH / g, or from 50 mg KOH / g to less than 150 mg KOH / g, or from 150 mg KOH / g to less than 300 mg KOH / g. The polyester polyol has an initial viscosity. The "initial viscosity," as used herein, is the viscosity of the polyester polyol prior to reaction with the isocyanate-silane adhesion promoter. The polyester polyol has an initial viscosity from 2,000 cP to 40,000 cP, or from 2,000 cP to 5,000 cP, or from 20,000 cP to 40,000 cP, or from 22,000 cP to 40,000 cP, or from 25,000 cP to 40,000 cP, or from 30,000 cP to 40,000 cP.

[0029] The composition includes the isocyanate-silane adhesion promoter (interchangeably referred to as "promoter"). An "isocyanate-silane adhesion promoter," as used herein, is a molecule with a hydrocarbon backbone, the hydrocarbon backbone having opposing ends and terminated on a first end by at least one, or one, isocyanate functional group (N=C=O) and terminated on a second end by a silane with Structure A:Structure A-Si-(OR1)X(R2)ywherein R1and R2each independently is a C1-C20 hydrocarbon group, or a C1-C12 hydrocarbon group, or a Ci-Cs hydrocarbon group, or a C1-C4 hydrocarbon group, or a C1-C3 hydrocarbon group, or a C1-C2 hydrocarbon group, x is an integer and is 1, 2 or 3, y is an integer and is 0, 1, or 2, and x+y = 3. The isocyanate-silane adhesion promoter can be an aliphatic isocyanate adhesion promoter, an aromatic isocyanate adhesion promoter, and combinations thereof. Nonlimiting examples of suitable isocyanate-silane adhesion promoters include 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3- isocyanatopropylmethyldiethoxysilane, 3-isocyanatopropylmethyldimethoxysilane,(isocyanatomethyl)methyldimethoxysilane, isocyanatomethyltrimethoxysilane, isocyanatomethyltriethoxysilane, and combinations thereof.

[0030] In an embodiment, the isocyanate adhesion promoter is selected from 3- isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropylmethyldiethoxysilane, 3-isocyanatopropylmethyldimethoxysilane, and combinations thereof.

[0031] In an embodiment, the isocyanate-silane adhesion promoter is 3- isocyanatopropyltriethoxysilane.

[0032] The composition includes the isocyanate-silane adhesion promoter at an OH:NCO equivalence ratio greater than 2.5:1. In other words, the composition contains the isocyanate- silane adhesion promoter in an amount to yield an OH:NCO equivalence ratio greater than 2.5:1. The "OH:NCO equivalence ratio," as used herein is the stoichiometric ratio of the number OH groups in the polyester polyol to the number of NCO groups (in the promoter). By way of example, when the number of OH groups equals the number of NCO groups, the OH:NCO equivalence ratio is 1:1. The isocyanate-silane adhesion promoter is present in an amount to yield an OH:NCO equivalence ratio greater than 2.5:1, or from greater than 2.5:1 to 8:1 , or from 3.0:1 to 7.8:1.

[0033] In an embodiment, the composition includes the reaction product of a polyester polyol with a functionality from 3.0 to 8.0, or from 3.0 to 4.0, an OH number (OHv) from 150 mg KOH / g to less than 300 mg KOH / g, and an initial viscosity from 20,000 cP to 40,000 cP at 25°C, or from 30,000 cP to 40,000 cP at 25°C. The composition includes an isocyanate-silane adhesion promoter that is isocyanatopropyltriethoxysilane in an amount to provide an OH:NCO equivalence ratio from 2.5:1 to 8.0:1. The composition has a final viscosity from 15,000 cP to 28,000 cP. The composition is a liquid at 25°C.

[0034] In an embodiment, the composition includes the reaction product of a polyester polyol with a functionality from 3.0 to 8.0, or from 3.0 to 4.0, an OH number (OHv) from 150 mg KOH / g to less than 300 mg KOH / g, and an initial viscosity from 20,000 cP to 40,000 cP at 25°C, or from 30,000 cP to 40,000 cP at 25°C. The composition includes an isocyanate-silane adhesion promoter that is isocyanatopropyltriethoxysilane in an amount to provide an OH:NCO equivalence ratio from 2.5:1 to 8.0:1. The composition has a final viscosity from 15,000 cP to 28,000 cP and the final viscosity is less than the initial viscosity. The composition is a liquid at 25°C. The composition is terminated with OH groups (and silane groups). As the OH:NCOequivalence ratio is greater than 2.5:1, the composition has no, or is otherwise void of, terminal NCO groups.

[0035] In an embodiment, the composition includes polyester polyol to the exclusion of polyether polyol. In other words, the composition is free of, or is otherwise void of, polyether polyol and the polyol component in the composition consists of only polyester polyol.

[0036] Bounded by no particular theory, Applicant discovered that capping part of the available OH groups of a polyester polyol with a reactive molecule that is the isocyanate-silane adhesion promoter unexpectedly (i) lowers the OHv of the final composition, (ii) simultaneously lowers the viscosity of the final composition, and (iii) does not yield any chain extension or branching reaction (which would increase the molecular weight of the final composition) as shown in the graph in FIG. 3.

[0037] By way of example, and not limitation, examples of the present disclosure will now be described in detail in the following examples.EXAMPLES

[0038] Materials used in the comparative samples (CS) and in the inventive examples (IE) are provided in Table 1 below.Table 1

[0039] According to the correlation that exists between molecular weight ("MW") and OHv, one way of lowering the OHv of a polyol is to increase its MW. This can be done in two ways: (1) synthesize longer polymeric chains by incorporating more monomers within the chain, and (2) chemical reaction to further promote the extension of already available polymeric chains. Comparative samples 1 and 2 explore these two routes.

[0040] In Table 1 above, the OHv values are provided for four readily available branched polyester polyols with different monomeric composition and progressively longer polymeric chains and therefore progressively increasing MW and decreasing OHv. Polyester polyols with OHv<250 mgKOH / g were evaluated.

[0041] Comparing Bester 12 to Bester 210, it is seen that at similar OHv, Bester 210 exhibits a slightly lower viscosity than Bester 12. This is due to the monomeric composition of the two polyester polyols. Bester 12 contains a portion of aromatic monomer which increases its final viscosity. Given this fact, a ready way to obtain low OHv for Bester 12 is to revert to purely aliphatic backbones in order to obtain low OHv branched polyester polyols with low viscosities. However, the branching of the polymer backbone does not allow for a significant decrease in viscosity. Furthermore, purely aliphatic backbones lead to overall lower performance levels when compared to aromatic backbones. This trade-off is not always acceptable especially in application areas where chemical and thermal resistance are required.

[0042] Comparing Bester 12 and Bester 115, it can be seen that when OHv is low, the viscosity of the polyester polyol is high. In fact, the viscosity of Bester 115 at 25°C is so high that the viscosity of Bester 115 had to be measured at a higher temperature (60°C) in order to obtain a viscosity reading even though Bester 115 is a liquid at 25°C.

[0043] Comparing Bester 115 to Bester 63C, it is seen that as OHv value lowers, the higher is the viscosity of the polyester polyol. In fact, the viscosity of Bester 63 at 25°C is so high that the viscosity of Bester 63C had to be measured at a higher temperature (50°C). Reliance on purely aliphatic backbones did not reduce the overall viscosity, but rather led to a waxy polyester polyol at 25°C.A. Synthesis

[0044] CS1

[0045] In a reaction flask equipped with a stirrer, a reflux condenser, a thermometer and a heating jacket, 1080 g of Bester 104 was loaded and heated to 45°C under stirring. 120 g of Isonate M125 was subsequently loaded, after having been pre-heated at 50°C and liquified. The temperature was raised to 60°C in 20 minutes after which it was set to 85°C. The reaction was run for 3 hours and 40 minutes under stirring before checking via FTIR that the NCO% was 0. The reaction flask, still under stirring, was then cooled down to 65°C before discharging the content.

[0046] CS2

[0047] In a reaction flask equipped with a stirrer, a reflux condenser, a thermometer and a heating jacket, 1056 g of Bester 648 was loaded and heated up to 45°C under stirring. 144 g of Isonate M125 was subsequently loaded, after having been pre-heated at 50°C and liquified. The temperature was raised to 65°C in 17 minutes after which it was set to 85°C. The reaction was run for 1 hour and 80 minutes under stirring before checking via FTIR that the NCO% was 0. The reaction flask, still under stirring, was then cooled down to 55°C before discharging the content.

[0048] I El

[0049] In a reaction flask equipped with a stirrer, a reflux condenser, a thermometer and a heating jacket, 712.2 g of Bester 12 was loaded after having been pre-heated at 60°C for 30 minutes. The reaction flask content was mixed and homogenized at 60°C for 40 minutes. 88.1 g of Silquest A-Link 25 was subsequently loaded, and the temperature was raised to 80°C. The reaction was run for 1 hour and 30 minutes under stirring before checking via FTIR that the NCO% was 0. The reaction flask, still under stirring, was then cooled down to 50°C before discharging the content.

[0050] IE2

[0051] In a reaction flask equipped with a stirrer, a reflux condenser, a thermometer and a heating jacket, 616.2 g of Bester 12 was loaded after having been pre-heated at 60°C for 30minutes. The reaction flask content was mixed and homogenized at 60°C for 40 minutes. 184.3 g of Silquest A-Link 25 was subsequently loaded, and the temperature was brought up to 80°C. The reaction was run for 1 hour and 30 minutes under stirring before checking via FTIR that the NCO% was 0. The reaction flask, still under stirring, was then cooled down to 50°C before discharging the content.

[0052] Table 2

[0053] Results

[0054] In Table 2, for CS1 and CS2 Isonate M 125 (monomeric pure MDI) was used to promote the extension of already available polymeric chains contained in two different polyester polyols, Bester 104 and Bester 648, both made from the same monomer starters: adipic acid, isophthalic acid and diethylene glycol. In each of CS1 and CS2, a reduction of the OHv of the polyester is obtained. As expected, each of CS1 and CS2 has a higher final viscosity (compared to initial viscosity) as a result of increasing the polymeric chains, and thereby increasing the MW.

[0055] CS1 exhibited higher viscosities both before and after the synthesis when compared to CS2 mainly due to the different ratio in the monomeric composition of the polyesters used. Linear polyester polyols were used for CS1 and CS2, because using a branched structure would have led to much higher viscosity increases that could not be measured with the Brookfield DV- 1 viscosimeter.

[0056] In inventive examples 1 and 2, different amounts of Silquest A-Link 25 were reacted with Bester 12 (a branched polyester polyol) to obtain increasing levels of OHv reduction.

[0057] Applicant discovered an innovative approach for lowering the OHv of a polyester polyol. Rather than attempting to increase the polyester polyol's MW as explained above, applicant discovered an isocyanate-silane adhesion promoter that acts as a capping agent for some of the OH groups available in the polyol.

[0058] By using a capping agent (i.e., the isocyanate-silane adhesion promoter), no chain extension or crosslinking reaction occurs that would impact the polyol's viscosity as described previously. Utilization of the capping agent modifies the functionality of the available polymeric chains by formally reducing the available OH groups of the polyester polyol, thereby lowering the OHv.

[0059] In Table 2, IE1-IE2 show that not only is the reduction of OHv possible, but surprisingly the final viscosity is reduced (compared to the initial viscosity) the more the OHv is lowered.

[0060] Silquest A-Link 25 (3-isocyanatopropyl triethoxysilane), is used to cap available OH groups of the polyester polyol by replacing the OH groups with a component having a silane moiety, the silane moiety enabling crosslinking at a later stage. The functionality, F, for the polyester polyol is greater than or equal to 3.0. A functionality of 2.0 leads to unwanted monofunctional polyester polyol chains or fully capped polyester polyol chains. Monofunctional polyester polyol chains are not suitable for further crosslinking and fully capped polyester polyol chains are no longer reactive.

[0061] Bounded by no particular theory, Applicant discovered low OHv (less than 300 mg KOH / g) branched polyester polyols with low viscosity are desirable for a number of reasons, particularly in formulation design for solventless (SL) 2 component (2K) polyurethane (PU) adhesives.

[0062] SL 2K PU adhesives typically include an OH component and an NCO component. The OH and NCO components can be either formulated as a blend of raw materials or as a prepolymer. The OHv and the viscosity of the OH component will be dependent on the raw materials in the case of both the blend and the prepolymer.

[0063] When mixing the NCO and OH components of a SL 2K PU adhesive, the mixing is typically performed in amounts that will lead to a stoichiometric excess of NCO groups. A stoichiometric excess of NCO groups allows proper curing of the adhesive as all the available OH groups will react with the available NCO while the remaining excess NCO portion can further cure by reacting with moisture. If the mixing was done in amounts that resulted in a stoichiometric excess of OH groups, the adhesive curing would stop as soon as all the available NCO groups are reacted leaving free OH groups with nothing else to chemically bond with, eventually resulting in poor adhesion properties.

[0064] The term "NCO index" is the stoichiometric excess of NCO in a reaction with a polyol, to form polyurethane. By way of example, an NCO index of 100 indicates a stochiometric 1:1 ratio of NCO groups and OH groups whereas an NCO index of 120 indicates a stoichiometric excess of NCO and an NCO index of 80 indicates a stoichiometric excess of OH. The NCO index is dependent on four parameters: (i) OH component (ii) OHv, (iii) the NCO component NCO% and (iv) the amount of NCO and OH components mixed together, which is generally called mix ratio. The way OHv, NCO% and mix ratio are bound to the index is such that, for a given amount of NCO component at a given NCO%, the lower the OHv the more OH component will be required to reach the same index. Furthermore, considering the range of NCO% and OHv traditionally used in SL 2K PU adhesives, a mix ratio typically includes 100 parts by weight (PBW) of NCO component, 30-60 PBW of OH component and an NCO index of 120-160.

[0065] Applicant discovered a way to lower the OHv of polyester polyol (and branched polyester polyol in particular) in polyurethane formulation design without increasing the viscosity (and without increasing the molecular weight) of the final composition. The reaction product of (i) a polyester polyol with functionality greater than or equal to 3.0 and OHv less than 300 KOH / mg and (2) an isocyanate adhesion promoter providing an OH:NCO equivalence ratio greater than 2.5:1 (or from greater than 2.5:1 to 8.0:1) unexpectedly yields a (final) composition with a final viscosity less than the initial viscosity of the polyester polyol and also has a final OHv value less than the OHv value of the polyester polyol. Nonlimiting examples of advantages for use of the present composition in polyurethane adhesive compositions include: (i) increased pot life and better cleanability, (ii) free NCO monomer content dilution for the reduction of whiteningeffect on metal and improved primary aromatic amine (PAA) decay, (iii) reduction in final viscosity (compared to the initial viscosity of the polyol component) which yields higher (faster) lamination speeds, and (v) the ability to use 100:100, or 80:100 NCO:mix ratios yielding product ease of use and NCO cost dilution.

[0066] It is specifically intended that the present disclosure not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims

Claims

CLAIMS1. A composition comprising: a reaction product of(1) a polyester polyol having a functionality greater than or equal to 3.0, an OH number (OHv) less than 300 mg KOH / g, and an initial viscosity;(2) an isocyanate-silane adhesion promoter providing an OH:NCO equivalence ratio greater than 2.5:1; and the composition has a final viscosity less than the initial viscosity.

2. The composition of claim 1 wherein the polyester polyol has a functionality from greater than or equal to 3.0 to 8.0, an OH number (OHv) from 150 mg KOH / g to less than 300 mg KOH / g, and an initial viscosity from 20,000 cP to 40,000 cP at 25°C.

3. The composition of any of claims 1-2 wherein the isocyanate-silane adhesion promoter is selected from the group consisting of an aliphatic isocyanate adhesion promoter, an aromatic isocyanate adhesion promoter, and combinations thereof.

4. The composition of any of claims 1-3 wherein the isocyanate-silane adhesion promoter is selected from the group consisting of 3-isocyanatopropyltriethoxysilane, 3- isocyanatopropyltri methoxysilane, 3-isocyanatopropylmethyldiethoxysilane, 3- isocyanatopropylmethyldimethoxysilane, and combinations thereof.

5. The composition of any of claims 1-4 wherein the isocyanate-silane adhesion promoter has an OH:NCO equivalence ratio from 2.5:1 to 8.0:1; the polyester polyol has an initial viscosity from 20,000 cP to 40,000 cP; and the composition has a final viscosity from 15,000 to 28,000 cP and the final viscosity is less than the initial viscosity.

6. The composition of any of claims 1-5 wherein the composition has an initial viscosity from 30,000 cP to 40,000 cP and a final viscosity from 15,000 cP to 28,000 cP.

7. The composition of any of claims 1-6 wherein the polyester polyol has a functionality from 3.0 to 8.0, an OHv from 150 mg KOH / g to less than 300 mg KOH / g and an initial viscosity from 30,000 cP to 40,000 cP; and the isocyanate-silane adhesion promoter is isocyanate propyltriethoxy silane having an OH:NCO equivalence ratio from 2.5:1 to 8.0:1.

8. The composition of any of claims 1-7 wherein the composition is a liquid at 25°C.

9. The composition of any of claims 1-8 wherein the composition is void of polyether polyol.

10. The composition of any of claims 1-9 wherein the composition is void of NCO terminal groups.

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