FIELD

The present disclosure relates to the use of a high silica zeolites in the production of polyurethane adhesives. More particularly, the present disclosure relates to a polyurethane adhesive comprising at least a high silica zeolite and a process to produce polyurethane adhesives.

INTRODUCTION

Polyurethane (PU) adhesives are widely utilized to bond wood, LVT, parquet, PVC and rubber floor to the concrete substrate for residential and commercial flooring applications. The polyurethane used in this application is a highly filled system formulated with various fillers and additives. The presence of the PU prepolymer and additives result in a musty inherent odor originating from volatile molecules (VOCs) trapped inside and slowly released through diffusion over the course of time. Emission of volatile molecules in the end product can have both regulatory and quality considerations, therefore PU adhesives with minimal VOCs content are highly desirable. Volatile molecules in PU adhesives can originate from unreacted monomers or as by-product molecules formed during the curing process. Typically, these unwanted VOCs are removed through time consuming and uneconomical stripping methods.

SUMMARY

A purpose of the present disclosure is to provide a composition for polyurethane prepolymers for use as adhesives and a method of production for said adhesives.

In one embodiment of the presently disclosed subject matter, the PU adhesives are incorporated with zeolites, which surprisingly results in a low odor or odor free adhesive composition. It was discovered that high silica zeolites (e.g., zeolites with a Si/ Al molar ratio of > 35) with low affinity for H2O molecules have a tremendous selectivity for nonpolar and polar organic molecules. These zeolites can physically adsorb small organic molecules in the presence of H2O and do not release adsorbed molecules even on subjecting it to high temperatures (e.g., 200°C).

The hydrophobic nature of these high silica zeolites prevents displacement of adsorbed VOC molecules by H2O molecules. Compared to other commercially available zeolites, these high silica alternatives show significant reduction in VOC molecules, specifically odor causing molecules at relatively low loading levels. Additionally, due to inert nature of these zeolites, as well as the need for a low concentration to be effective (e.g., lwt%), there is minimal impact on mechanical and physical properties of the resulting adhesives. The use of these high silica zeolites can reduce the total aldehyde content by > 80% (e.g., < lOppm) and decrease the total VOC content by > 50%.

In one embodiment, the polyurethane prepolymer can be present from 90 to 99.9 wt% with the zeolite being be present from 0.1 to 20 wt% and stable in temperature range up to 200°C.

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

DETAILED DESCRIPTION

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the method belongs. Also, all publications, patent applications, patents, and other references mentioned herein are incorporated by reference. As disclosed herein, the term "composition", "formulation" or "mixture" refers to a physical blend of different components, which is obtained by mixing simply different components by a physical means. As disclosed herein, “and/or” means “and, or as an alternative”. All ranges include endpoints unless otherwise indicated.

All parts by weight relative to the components of the adhesive composition are based on 100 total parts by weight of the adhesive composition. For purposes of United States patent practice, the contents of any referenced patent, patent application or publication are incorporated by reference in their entirety (or its equivalent US version is so incorporated by reference) especially with respect to the disclosure of definitions (to the extent not inconsistent with any definitions specifically provided in this disclosure) and general knowledge in the art.

The numerical ranges in this disclosure are approximate, and thus may include values outside of the range unless otherwise indicated. Numerical ranges include all values from and including the lower and the upper values, in increments of one unit, provided that there is a separation of at least two units between any lower value and any higher value. As an example, if a compositional, physical or other property, such as, for example, temperature, is from 100 to 1,000, then all individual values, such as 100, 101, 102, etc., and sub ranges, such as 100 to 144, 155 to 170, 197 to 200, etc., are expressly enumerated. For ranges containing values which are less than one or containing fractional numbers greater than one (e.g., 1.1, 1.5, etc.), one unit is considered to be 0.0001, 0.001, 0.01 or 0.1, as appropriate. For ranges containing single digit numbers less than ten (e.g., 1 to 5), one unit is typically considered to be 0.1. These are only examples of what is specifically intended, and all possible combinations of numerical values between the lowest value and the highest value enumerated, are to be considered to be expressly stated in this disclosure. Numerical ranges are provided within this disclosure for, among other things, molecular weight and the relative amounts of the individual components in the composition.

“Comprising”, “including”, “having” and like terms mean that the composition, process, etc. is not limited to the components, steps, etc. disclosed, but rather can include other, undisclosed components, steps, etc. In contrast, the term “consisting essentially of’ excludes from the scope of any composition, process, etc. any other component, step etc. excepting those that are not essential to the performance, operability or the like of the composition, process, etc. The term “consisting of’ excludes from a composition, process, etc., any component, step, etc. not specifically disclosed. The term “or”, unless stated otherwise, refers to the disclosed members individually as well as in any combination.

Additionally, other optionally auxiliary components such as surfactant, catalyst, additional blowing agent, flame retardant additive, etc. may be pre-mixed into the isocyanate-reactive component or the isocyanate component, which is then mixed with the other components to produce the PU adhesive or admixed into the adhesive composition as separate streams. Not all of these optional auxiliary components are required for the foam production and should not be read as limiting the scope of this disclosure in any way.

Various embodiments of the presently disclosed composition may vary in the amounts, contents or concentration of the isocyanate-reactive component and the isocyanate component. The isocyanate component in these embodiments are calculated based on the total weight of the foam-forming composition, i.e. combined weight of the isocyanate-reactive component, the isocyanate component, the zeolite, and all optional auxiliary components if not already accounted for in another component.

I. Polyurethane Adhesive

The adhesive composition includes 20 to 50 weight percent (wt.%) of a moisture curable polymer system; 30 to 60 wt.% of a calcium carbonate filler system; 5 to 15 wt.% of a organic plasticizer; and 0.1 to 10 wt.% of a silane based adhesion promoter, where the wt.% of the moisture curable polymer system, the calcium carbonate filler system, the seed oil based fatty acid ester and the silane based adhesion promoter are based on the total weight of the adhesive composition.

A variety of moisture curable polymer systems can be used with the adhesive compositions of the present disclosure. For example, the moisture curable polymer system is a reaction product of an isocyanate component and a polyol component, where the moisture curable polymer system has a free isocyanate content (%NCO) from 1 weight percent (wt.%) to 14 wt.%. For the various embodiments, the moisture curable polymer system is formed by combining an excess of an isocyanate (e.g., a diisocyanate) with an isocyanate-reactive composition (e.g., a polyol), where one of the isocyanate (NCO) groups of the isocyanate component reacts with one of the hydroxyl (OH) groups of the polyol. The other end of the polyol reacts with another isocyanate, where the resulting isocyanate prepolymer has an isocyanate group on both ends. The moisture curable polymer system can be a diisocyanate itself, but has a greater molecular weight, a higher viscosity, a lower isocyanate content by weight (%NCO), and a lower vapor pressure as compared to the isocyanate used in forming the moisture curable polymer system. In addition to a diol, a triol or higher functional polyol could also be used for the polyol in the reaction, as long as an excess amount of diisocyanate is used. Molar ratios of diisocyanate to polyol greater than two to one can also be used in forming the moisture curable polymer system.

The urethane prepolymers have an average isocyanate functionality sufficient to allow the preparation of a crosslinked polyurethane upon cure and not so high that the polymers are unstable. Stability in this context means that the prepolymer or adhesive prepared from the prepolymer has a shelf life of at least 6 months at ambient temperature (23° C.), in that it does not demonstrate an increase in viscosity during such period which prevents its application or use. Preferably the prepolymer or adhesive prepared therefrom does not undergo an increase in viscosity of more than 50 percent during the stated period. Preferably, the average isocyanate functionality is greater than 2.2 and preferably at least 2.4. Below 2.2 the ability of the prepolymer to crosslink sufficiently to achieve the desired strength of the cured adhesive is compromised. Preferably the average isocyanate functionality of the prepolymer is 3.0 or less and more preferably 2.8 or less. Above 3.0 average isocyanate functionality the prepolymer and adhesives prepared from the prepolymer may exhibit unacceptable stability.

The prepolymer preferably has a free isocyanate content which facilitates acceptable strength in adhesives prepared from the prepolymers after 60 minutes and stability of the prepolymer. Preferably, the free isocyanate content is greater than 2.2 percent by weight or greater based on the weight of the prepolymer, more preferably 2.5 percent by weight or greater, even more preferably 2.7 percent by weight or greater, and preferably 15 percent by weight or less, even more preferably 12 percent by weight or less and most preferably 10 percent by weight or less. Preferably, the weight average molecular weight of the prepolymer is 3,000 or greater, more preferably 4,000 or greater, even more preferably 5,000 or greater and most preferably 6,000 or greater; and is preferably 20,000 or less, more preferably 15,000 or less, even more preferably 10,000 or less and most preferably 8,000 or less. The prepolymer preferably exhibits a viscosity which facilitates formulation of a pumpable adhesive which has good green strength. Preferably the viscosity of the prepolymer is 20,000 centipoise (cps) or less and more preferably 13,000 or less, preferably 3,000 or greater, and more preferably 6,000 cps or greater and most preferably 8,000 cps or greater. The viscosity of the adhesive can be adjusted with fillers although the fillers cannot improve the green strength of the final adhesive. Below 3,000 cps the adhesive prepared from the prepolymer may exhibit poor green strength. Above 20,000 the prepolymer may be unstable and subject to gelling. The prepolymer may be prepared by any suitable method, such as by reacting one or more compounds containing on average more than one, and preferably at least about two, isocyanate-reactive groups and a dispersion triol with an excess over stoichiometry of one or more polyisocyanates under reaction conditions sufficient to form a prepolymer having isocyanate functionality and free isocyanate content which meets the criteria discussed above.

Isocyanate

Preferable polyisocyanates for use in preparing the prepolymer include any aliphatic, cycloaliphatic, aryl aliphatic, heterocyclic or aromatic polyisocyanate, or mixture thereof, with an average isocyanate functionality of at least 2.0 and an equivalent weight of at least 80. Preferably, the isocyanate functionality of the polyisocyanate is at least 2.0, more preferably at least 2.2, and is more preferably at least 2.3; and is preferably no greater than 4.0, more preferably no greater than 3.5, and is most preferably no greater than 3.0. Higher functionalities may also be used, but their use may cause excessive crosslinking, resulting in an adhesive which is too viscous to handle and apply easily, can cause the cured adhesive to be too brittle and cause foaming due to carbon dioxide gassing. Preferably, the equivalent weight of the polyisocyanate is at least 100, more preferably at least 110, and is more preferably at least 120; and is preferably no greater than 300, more preferably no greater than 250, and is most preferably no greater than 200.

Examples of such polyisocyanates include ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, cyclobutane- 1,3- diisocyanate, cyclohexane- 1,3- and 1,4-diisocyanate and mixtures of these isomers; 1- isocyanato-3,3,5-trimethyl-5-isocyanato methyl cyclohexane; 2,4- and 2,6-hexahydrotolylene diisocyanate and mixtures of these isomers, hexahydrol, 3- and/or 1,4-phenylene diisocyanate, perhydro-2,5'- and/or 4,4'-diphenyl methane diisocyanate, 1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate and mixtures of these isomers, diphenyl methane-2,4'- and/or 4,4'-diisocyanate, naphthylene-l,5-diisocyanate, triphenyl methane-4,4',4'-tri-isocyanate, polyphenyl polymethylene polyisocyanates of the type obtained by condensing aniline with formaldehyde, followed by phosgenation such as described in British Patents 874,430 and 848,671, perchlorinated aryl polyisocyanates as described in German Auslegeschrift 1,157,601, polyisocyanates containing carbodiimide groups as described in German Patent 1,092,007, diisocyanates of the type described in U.S. Pat. No. 3,492,330, polyisocyanates containing allophanate groups of the type described in British Patent 994,890, Belgian Patent 761,626 and Dutch Patent Application No. 7,102,524, polyisocyanates containing isocyanurate groups as described in German Patents 1,022,789, 1,222,067, 1,027,394, 1,929,034 and 2,004,048, polyisocyanates containing urethane groups as described in Belgian Patent 752,261 or U.S. Pat. No. 3,394,164, polyisocyanates containing acrylated urea groups as in German Patent 1,230,778, polyisocyanates containing biuret groups as described in German Patent 1,101,392, British Patent 889,050 and French Patent 7,017,514, polyisocyanates obtained by telomerization reactions described in Belgian Patent 723,640, polyisocyanates containing ester groups as described in British Patents 965,474 and 1,072,956, USP 3,567,763 and German Patent 1,231,688 and reaction products of the aforementioned isocyanates with acetals as described in German Patent 1,072,385. Preferably the polyisocyanate is an aromatic or cycloaliphatic polyisocyanate such as diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, tetramethylxylene diisocyanate, and is most preferably diphenylmethane-4,4'-diisocyanate.

The polyisocyanates are used in a sufficient amount to form an advanced polyurethane prepolymer having free reactive isocyanate moieties. Preferably the amount of polyisocyanate is 5 percent by weight or greater based on the starting materials and more preferably 9 percent by weight or greater and preferably 20 percent by weight or less, more preferably 15 percent by weight or less and even more preferably 11 percent by weight or less.

Isocyanate-Reactive Compound

In the present disclosure, other isocyanate-reactive compositions besides the polyol component can be used in forming the moisture curable polymer system of the present disclosure.

The term “isocyanate-reactive compound” as used herein includes water and any organic compound having on average more than one, preferably at least two, and preferably no more than 4, isocyanate-reactive moieties, such as a compound containing an active hydrogen moiety or an imino-functional compound. For the purposes of this invention, an active hydrogen moiety refers to a moiety containing a hydrogen atom which, because of its position in the molecule, displays significant activity according to the Zerewitnoff test described by Wohler in the Journal of the American Chemical Society, Vol. 49, p. 3181 (1927). Illustrative of such active hydrogen moieties are — COOH, —OH, — NH2— NH— , — CONH2, — SH, and — CONH— . Typical active hydrogen-containing compounds include polyols, polyamines, polymercaptans, polyacids and compounds containing at least one oxazolidine moiety. Suitable imino-functional compounds are those which have at least one terminal imino group per molecule, such as are described, for example, in U.S. Pat. No. 4,910,279.

Preferable isocyanate-reactive compounds are polyols. The term polyol as here used includes any organic compound having on average more than one and preferably at least two, and preferably no more than four, isocyanate-reactive hydroxyl moieties.

The polyol component can have a number average molecular weight of 1,000 g/mol to 6,000 g/mol. Other number average molecular weight values may also be possible. The number average molecular weight values reported herein are determined by end group analysis, as is known in the art.

Other examples of suitable polyols include those polymers or copolymers formed with propylene oxide that have a hydroxyl equivalent weight of at least 300. The propylene oxide may be 1,3-propylene oxide, but more typically is 1 ,2-propylene oxide. If a copolymer, the comonomer is another copolymerizable alkylene oxide such as, for example, ethylene oxide, 2,3- butylene oxide, tetrahydrofuran, 1,2-hexane oxide, and the like. A copolymer may contain 75% or more by weight, preferably 85% or more polymerized propylene oxide, based on the total weight of polymerized alkylene oxides. A copolymer preferably contains no more than 15%, especially no more than 5% by weight polymerized ethylene oxide. The polymer or copolymer of propylene oxide should have a nominal functionality of at least 2.0. The nominal functionality preferably is 2.5 to 6, more preferably 2.5 to 4 or 2.5 to 3.3. The hydroxyl equivalent weight of the polymer or copolymer of propylene oxide is at least 300, preferably at least 500, more preferably 500 to 3200, in some embodiments 600 to 3000 and in particular embodiments from 800 to 2500. The polyol can also be formed of a blend, where the polyol blend includes a blend of the diol and triol. The diol can have an average molecular weight (Mw) of 500 to 8,000 grams/mole and a triol having an average molecular weight (Mw) of 2500 to 6500 grams/mole. In various embodiments, the polyol component can have a hydroxyl number of from 10 mg KOH/g to 700 mg KOH/g. In still other embodiments, the polyol component has a hydroxyl number of from 15 mg KOH/g to 100 mg KOH/g, or from 20 mg KOH/g to 50 mg KOH/g. As used herein, a hydroxyl number is the milligrams of potassium hydroxide equivalent to the hydroxyl content in one gram of the polyol or other hydroxyl compound. The polyol can also have a number averaged isocyanate reactive group functionality of 1.6 to 6, such as 2 to 6 or 3 to 5.

Preferable polyols useful in the preparation of the prepolymers include, for example, polyether polyols, polyester polyols, poly(alkylene carbonate)polyols, hydroxyl-containing poly thioethers, polymer polyols, and mixtures thereof. Poly ether polyols are well-known in the art and include, for example, polyoxyethylene, polyoxypropylene, polyoxybutylene, and polytetramethylene ether diols and triols which are prepared by reacting an unsubstituted or halogen- or aromatic-substituted alkylene oxide with an initiator compound containing two or more active hydrogen groups such as water, ammonia, a polyalcohol, or an amine. Such methods are described, for example, in U.S. Pat. Nos. 4,269,9945; 4,218,543; and 4,374,210. In general, polyether polyols may be prepared by polymerizing alkylene oxides in the presence of an active hydrogen-containing initiator compound.

Preferable alkylene oxides include ethylene oxide, propylene oxide, butylene oxides, styrene oxide, epichlorohydrin, epibromohydrin, and mixtures thereof. Preferable initiator compounds include water, ethylene glycol, propylene glycol, butanediol, hexanediol, glycerin, trimethylol propane, pentaerythritol, hexanetriol, sorbitol, sucrose, hydroquinone, resorcinol, catechol, bisphenols, novolac resins, phosphoric acid, amines, and mixtures thereof.

Polyester polyols are also well-known in the art and may be prepared by reacting a poly carboxy lie acid or anhydride thereof with a polyhydric alcohol. Examples of preferable polycarboxylic acids include succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, maleic acid, trimellitic acid, phthalic acid anhydride, tetrahydrophthalic acid anhydride, hexahydrophthalic acid anhydride, tetrachlorophthalic acid anhydride, endomethylene tetrahydrophthalic acid anhydride, maleic acid anhydride, glutaric acid anhydride, fumaric acid, and mixtures thereof. Examples of preferable polyhydric alcohols useful in preparing polyester polyols include ethylene glycols, propane diols, butane diols, 1,6- hexanediol, 1,8-octanediol, neopentylglycol, glycerol, trimethylol propane, pentaerythritol, quinitol, mannitol, sorbitol, methyl glycoside, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycols, polypropylene glycols, and mixtures thereof. Preferable polymer polyols include dispersions of polymers of vinyl monomers in a continuous polyol phase, particularly dispersions of styrene/acrylonitrile copolymers. Also useful are the so-called polyisocyanate polyaddition (PIPA) polyols (dispersions of polyureapolyurethane particles in a polyol) and the polyurea dispersions in polyols (PHD polyols). Copolymer polyols of the vinyl type are described, for example, in U.S. Pat. Nos. 4,390,645, 4,463,107, 4,148,840 and 4,574,137.

Preferably, the polyol(s) have an average functionality of at least 1.5, more preferably at least 1.8 and most preferably at least 2.0; and is preferably no greater than 4.0, more preferably no greater than 3.5 and most preferably no greater than 3.0. Preferably, the equivalent weight of the polyol(s) is at least 200, more preferably at least 500 and more preferably at least 1,000; and is preferably no greater than 3,500, more preferably no greater than 3,000 and most preferably no greater than 2,500.

Preferably the polyol is a mixture of one or more diols and one or more triols. Preferably the one or more polyols are polyether polyols and more preferably polyoxyalkylene oxide polyols. Most preferred, however, are ethylene oxide-capped polyols prepared by reacting glycerine with propylene oxide, followed by reacting the product with ethylene oxide.

The polyols are present in an amount sufficient to react with most of the isocyanate groups of the isocyanates leaving enough isocyanate groups to correspond with the desired free isocyanate content of the prepolymer. Preferably the polyols are present in an amount of 30 percent by weight or greater based on the prepolymer, more preferably 40 percent by weight or greater and most preferably 50 percent by weight or greater. Preferably the polyols are present in an amount of 80 percent by weight or less based on the prepolymer, more preferably 75 percent by weight or less and most preferably 70 percent by weight or less. In the embodiment where the polyols comprise a mixture of diols and triols the amount of diols present is preferably 10 percent by weight or greater based on the prepolymer, more preferably 17 percent by weight or greater and most preferably 19 percent by weight or greater; and 30 percent by weight or less based on the prepolymer, more preferably 23 percent by weight or less and most preferably 21 percent by weight or less. In the embodiment where the polyols comprise a mixture of diols and triols the amount of triols present is preferably 15 percent by weight or greater based on the prepolymer, more preferably 25 percent by weight or greater and most preferably 28 percent by weight or greater; and preferably 40 percent by weight or less based on the prepolymer, more preferably 35 percent by weight or less and most preferably 32 percent by weight or less. The proportion of diol to triol is chosen to achieve the desired isocyanate functionality of the prepolymer. Calcium Carbonate Filler

The adhesive composition may further include 30 to 60 wt.% of a calcium carbonate filler system. Other preferred wt.% ranges for the calcium carbonate filler system as used in the adhesive composition include 30 to 50 wt.%; 30 to 40 wt.%; 40 to 60 wt.%; 40 to 50 wt.% and 50 to 60 wt.%, where the wt.% is based on the total weight of the adhesive composition. For the various embodiments, the calcium carbonate filler system does not include an aluminum silicate.

For the various embodiments, the calcium carbonate filler system includes calcium carbonate (CaCCh) having a spheroidal shape. As used herein, a spheroidal shape includes prolate spheroids, oblate spheroids and/or spheres. For the various embodiments, two groups of the spheroidal particles of calcium carbonate constitute the calcium carbonate filler system of the present disclosure. Specifically, the calcium carbonate filler system is formed from a first spheroidal particle of calcium carbonate having an equivalent spherical mean diameter of 70 nanometer (nm) to 15 micrometer (pm); and a second spheroidal particle of calcium carbonate having an equivalent spherical mean diameter of greater than 15 pm to 200 pm. It is appreciated that while a single value for the equivalent spherical mean diameter for each of the first spheroidal particle and the second spheroidal particle is given, each have a size distribution where the wt.% of calcium carbonate particles having an equivalent spherical mean diameter of 45 pm or greater (Plus 325 Mesh, wt.%) for a given size of either the first spheroidal particle or the second spheroidal particle is from 0.003 wt.% to 0.8 wt.% for the first spheroidal particle and from 8 to 20 wt.% for the second spheroidal particle.

Preferably, the calcium carbonate filler system is formed from the first spheroidal particle of calcium carbonate having an equivalent spherical mean diameter of 1 pm to 10 pm and the second spheroidal particle of calcium carbonate having an equivalent spherical mean diameter of 15 pm to 40 pm, where the wt.% of the first spheroidal particle and the second spheroidal particle are based on the total weight of the calcium carbonate filler system. More preferably, the calcium carbonate filler system is formed from the first spheroidal particle of calcium carbonate having an equivalent spherical mean diameter of 2 pm to 5 pm and the second spheroidal particle of calcium carbonate having an equivalent spherical mean diameter of 20 pm to 30 pm, where the wt.% of the first spheroidal particle and the second spheroidal particle are based on the total weight of the calcium carbonate filler system. In one specific embodiment, the calcium carbonate filler system is formed from the first spheroidal particle of calcium carbonate having an equivalent spherical mean diameter of 3 pm and the second spheroidal particle of calcium carbonate having an equivalent spherical mean diameter of 25 pm. For the various embodiments, the calcium carbonate filler system has 5 to 50 wt.% of the first spheroidal particle of calcium carbonate having the equivalent spherical mean diameter of 70 nm to 15 pm, as described herein, and 50 to 95 wt.% of the second spheroidal particle of calcium carbonate having the equivalent spherical mean diameter of greater than 15 pm to 200 pm, as described herein. Preferably, the calcium carbonate filler system has 25 to 50 wt.% of the first spheroidal particle of calcium carbonate having the equivalent spherical mean diameter of 70 nm to 15 pm, as described herein, and 50 to 75 wt.% of the second spheroidal particle of calcium carbonate having the equivalent spherical mean diameter of greater than 15 pm to 200 pm, as described herein. In one preferred embodiment, the calcium carbonate filler system has 50 wt.% of the first spheroidal particle of calcium carbonate having the equivalent spherical mean diameter of 70 nm to 15 pm, as described herein, and 50 wt.% of the second spheroidal particle of calcium carbonate having the equivalent spherical mean diameter of greater than 15 pm to 200 pm, as described herein. In another preferred embodiment, the calcium carbonate filler system has 25 wt.% of the first spheroidal particle of calcium carbonate having the equivalent spherical mean diameter of 70 nm to 15 pm, as described herein, and 75 wt.% of the second spheroidal particle of calcium carbonate having the equivalent spherical mean diameter of greater than 15 pm to 200 pm, as described herein.

The wt.% of the first spheroidal particle and the second spheroidal particle provided herein are based on the total weight of the calcium carbonate filler system. For the calcium carbonate filler system provided herein, the wt.% of both the first spheroidal particle and the second spheroidal particle total 100 wt.%. In other words, no other filler(s) are present in the calcium carbonate filler system provided herein.

In an alternative embodiment, other fillers that can be used with the calcium carbonate filler system include, but are not limited to one or more of precipitated and colloidal calcium carbonates, reinforcing silicas such as fumed silicas, precipitated silicas, silica gels and hydrophobized silicas and silica gels; crushed and ground quartz, alumina, aluminum hydroxide, titanium hydroxide, diatomaceous earth, iron oxide, carbon black, graphite, mica, talc, and the like. When such additional fillers are present (i.e., if other fillers are present in the calcium carbonate filler system), the calcium carbonate filler system and the other fillers comprise 20 to 80, more typically 30 to 70 and even more typically 40 to 60, wt.% of the total weight of the adhesive composition. Seed Oil Based Fatty Acid Ester

The adhesive composition further includes 5 to 15 wt.% of a seed oil based fatty acid ester, where the wt.% is based on the total weight of the adhesive composition, where the seed oil based fatty acid ester acts as a plasticizer. The seed oil based fatty acid ester of the present disclosure is a fatty acid ester that is produced by the transesterification of a seed oil that replaces the glycerol component of the seed oil with a different alcohol. A preferred example of the seed oil includes soybean oil. Other examples of vegetable oils that may also be useful include, but are not limited to, those from castor, olive, peanut, rapeseed, corn, sesame, cotton, canola, safflower, linseed, palm, grapeseed, black caraway, pumpkin kernel, borage seed, wood germ, apricot kernel, pistachio, almond, macadamia nut, avocado, sea buckthorn, hemp, hazelnut, evening primrose, wild rose, thistle, walnut, sunflower, jatropha seed oils, or a combination of two or more of these oils. The use of other seed oils in also possible. Examples of animal products that might be useful include lard, beef tallow, fish oils and mixtures of two or more of these products. Additionally, oils obtained from organisms such as algae may also be used. Combination of vegetable, algae, and animal-based oils/fats may also be used.

Examples of the alcohol used in the transesterification include one or more of an organic mono- or poly-alcohol including a Ci to Cis organic moiety. More preferably, the alcohol is a Ci to Ce mono-alcohol, where the C4 to C6 group, when present, can be a straight or branched chain alkyl group. The most preferred alcohols are selected from methanol, ethanol, propanol, isopropanol, butanol, and mixtures thereof, with methanol normally being used.

As appreciated and known in the art, the seed oil based fatty acid ester can be prepared by the transesterification of the seed oil, during which the triglyceride of the seed oil reacts with the alcohol in the presence of a strong acid or base, producing a mixture of fatty acids alkyl esters and glycerol. Preferably, methanol is used in the transesterification process to produce a fatty acid methyl ester. For example, in one preferred embodiment the seed oil based fatty acid ester is a methyl ester produced from soybean oil. A commercial example of the preferred methyl ester produced from soybean oil includes a soybean oil methyl ester sold under the trade designator SOYGOLD available from CHEMPOINT, where SOYGOLD 1100 is one preferred example of the soybean oil methyl ester.

Silane Based Adhesion Promoter

The adhesive composition further includes 0.1 to 10wt.% of a silane based adhesion promoter, where the wt.% is based on the total weight of the adhesive composition. The silane based adhesion promoter of the present disclosure can be a bi-functional silanol coupling agent having terminal reactive groups of an amine, an isocyanate or an epoxy group. Suitable examples include 3 -glycidoxypropyltrimethoxy silane (GLYMO), glycidoxypropyltriethoxysilane (GLEO) isocyanatopropyltrimethoxysilane or combinations thereof. Examples of other useful adhesion promoters include N-2-aminoethyl-3-aminopropyl- triethoxysilane, gamma-aminopropyltriethoxysilane, gamma-aminopropyltrimethoxysilane, aminopropyltrimethoxysilane, bis-gamma-trimethoxysilypropyl)amine, N-phenyl-gamma- aminopropyltrimethoxysilane, triaminofunctionaltrimethoxysilane and gamma-aminopropyl- methyldiethoxysilane. The composition typically comprises, if present, 0.1 to 10, more typically 0.5 to 8 and even more typically 1 to 6 wt.% of the adhesion promoter.

Optional Additives

For the various embodiments, the adhesive composition can further include optional additives. For example, the adhesive composition can further include 0.5 to 4 wt.% of a silica based rheology modifier, wherein the wt.% is based on the total weight of the adhesive composition. Examples of the silica based rheology modifier include polydimethylsiloxane treated fumed silica such as those commercially available under the trade designator AEROSIL R202 or AEROSIL R805 (EVONIK).

The adhesive composition may further include a variety of other optional additives, where when present the optional additives may be present in an amount from 0.1 wt.% to 5 wt.% based on a total weight of the adhesive composition. Examples of the optional additives include, but are not limited to, a zeolite such as a molecular sieve powder (e.g., available from W.R. Grace under the trade name SYLOSIV). For example, the zeolite may be a crystalline aluminosilicate. An amount of the zeolite may be from 0.1 wt.% to 2 wt.%, based on the total weight of the adhesive composition. Additional examples of optional additives further include a catalyst for promoting reactions between free isocyanate of the adhesive composition and atmospheric moisture such that the reaction between the isocyanate(s) and the isocyanate reactive component occurs when the adhesive composition is dispensed from the can or cylinder. Examples of such catalysts include amine catalysts, metal complexes, or combinations thereof. The catalyst may be present in an amount of from 0.01 wt.% to 1 wt.%, from 0.05 wt.% to 0.5 wt.%, 0.1 to 1 wt.% or from 0.1 wt.% to 0.2 wt.% based on the total weight of the adhesive composition.

Amine catalysts may include organic compounds that contain at least one tertiary nitrogen atom (e.g., a tertiary amine) and are capable of catalyzing the free isocyanate groups in the adhesive composition. Examples include amidines or guanidines, such as for example 1,4- <Uazabicyclo[2.2.2]octane (DABCO), l,8-diazabicyclo[5.4.0]undec-7-ene (DBU), triethylenediamine, tetramethylethylenediamine, pentamethyldiethylene triamine, bis(2- dimethylaminoethyl)ether, triethylamine, tripropylamine, tributylamine, triamylamine, pyridine, quinoline, dimethylpiperazine, piperazine, N,N-dimethylcyclohexylamine, N-ethyl-morpholine, 2,2'-dimorpholinodiethylether ("DMDEE"), 2-methylpropanediamine, methyltriethylenediamine, 2,4,6-tri(dimethylamino methyl)phenol, N,N',N"-tris(dimethylamino-propyl)sym- hexahydrotriazine, and mixtures thereof. In further embodiments, the amine catalyst includes bis(2-dimethylamino-ethyl)ether, dimethylcyclohexylamine, N,N-dimethyl-ethanolamine, triethylenediamine, triethylamine, 2,4,6-tri(dimethylaminomethyl)phenol, N,N',N- ethylmorpholine, organometallic catalysts based on tin, zinc art l bismuth, for example dibutyltin dilaurate and/or mixtures thereof.

Additional optional additive includes, but are not limited to, a pigment, a flame retardant, an antibacterial agent, a thermostabilizing agent, paraffins or fatty alcohols or dimethylpolysiloxanes, chain extender, additional rheology additives, dyes, adhesion promoters, stabilizers against ageing and weathering, plasticizers, fungistatic and bacteriostatic substances.

II. High Silica Zeolites

The high silica zeolite additive may have a silicon to aluminum (Si/ Al) molar ratio of greater than 500. These zeolites are porous and have pore sizes > 10 A, capable of capturing large molecules. The amount of zeolite to the other foam forming composition components may be from 0.1 to 20 wt% zeolite and from 90 to 99.9 wt% urethane prepolymer. Other preferred embodiments may feature 0.2 to 10 wt% zeolite, 0.25 to 2.5 wt% zeolite, etc. Exceeding these relative amounts could affect the physical properties of an adhesive. The zeolites themselves are stable at temperatures up to 600°C and can also function at (or even below) room temperature.

One example of such a zeolite additive is ABSCENTS 3000 Cone, is a hydrophobic zeolite additive, with a silica-to-alumina ratio of 630, available from Honeywell UoP. In various preferred embodiments, the zeolite may have a silica-to-alumina ratio greater than: 35, 75, 150, 300, 500, and even 600.

The high silica zeolites in the embodiments above and other embodiments may be described as a silica polymorph wherein least 90% (preferably at least 95%) of the framework tetrahedral oxide units are SiO2 tetrahedra (e.g., Silicalite and F-Silicalite). In other embodiments, the zeolite may be described as an aluminosilicate, wherein the SiO2/A12O3 molar ratios are greater than approximately 18 and preferably greater than approximately 35. These exhibit the requisite degree of hydrophobicity. The SiO2/A12O3 molar ratio for an aluminosilicate may also be from about 35 and up, preferably from 200 to 500. Such aluminosilicate may be the commercially available zeolites ZSM-5, ZSM-11, ZSM-35, ZSM-23, ZSM-38.

Different zeolite species have different crystalline structures that determine the distribution, shape, and size of the zeolite’s pores. Natural zeolites may crystallize in a variety of natural processes, while artificial zeolites may be crystallized, for example, from a silica- alumina gel in the presence of templates and alkalis. There are over 200 known types of zeolite crystal structures. An MFI crystal structure, which may also be referred to as a silicate- 1 crystal structure, is a zeolite structure comprising multiple pentasil units connected by oxygen bridges which form pentasil chains, and having the chemical formula: Na _n Al _n Si96- _n Oi92- I6H2O, wherein n is greater than zero and less than 27. A faujasite (“FAU”) crystal structure, which may also be referred to a Y-type crystal structure or an IZA crystal structure, is a zeolite crystal structure that consists of sodalite cages which are tetrahedrally connected through hexagonal prisms, and which has a pore formed by a 12-membered ring. In aspects, the composition comprises a zeolite having a mixture of crystal structures, wherein the mixture of crystal structures comprises an MFI crystal structure and an FAU crystal structure.

The zeolites used in various embodiments of the presently disclosed subject matter may also be described by various other physical properties. Non- limiting examples for these properties include: the adsorption capacity of water vapor (at 25 °C and water vapor pressure (p/pO) of 4.6 torr) should not be greater than 10wt%, and preferably not greater than 6wt%. The pore diameter should be of at least 5.5A, preferably at least 6.2A. The zeolite should not contain water in the internal cavities of the microporous structure. The zeolite should also contain less than 2.0 wt% alkali metal on an anhydrous basis. One preferred embodiment features zeolite(s) with an Si/ Al molar ratio of 5 - 650, a pore volume of 0.1 - lcm3/g, a BET value of 50 -1000 m2/g, and water adsorption from 5 -50 cm3/g. Several zeolites and their various physical properties can be seen in the chart below.

Chart 1 : Zeolite Properties III. Method of Prepolymer Preparation

The polyurethane prepolymer may be prepared by any suitable method, such as bulk polymerization and solution polymerization. The reaction to prepare the prepolymer is carried out under anhydrous conditions, preferably under an inert atmosphere such as a nitrogen blanket, to prevent crosslinking of the isocyanate groups by atmospheric moisture.

The polyurethane prepolymer is preferably prepared by contacting the compounds or polymers containing isocyanate-reactive groups in the absence of catalyst and heating the mixture to 45° C. or greater, more preferably 48° C. or greater. The mixture is heated to a temperature of 55° C. or less, more preferably 49° C. or less. The isocyanate is then added to the mixture and the mixture is subjected to mixing so as to evenly disperse the polyisocyanate in the reaction mixture. Thereafter the polyurethane catalyst is added. After addition of the catalyst an exotherm generally results, preferably the exotherm peak is 58° C. or greater and more preferably 60° C. or greater. Preferably the exotherm peak is 70° C. or less, more preferably 65° C. or less. Above 70° C. the reaction mixture gels. Thereafter plasticizer may be added after the exotherm recedes, that is the temperature drops, to dilute the reactants and quench the reaction. The reaction should be run such that all free isocyanate-reactive moieties are reacted with isocyanate moieties.

The reaction mixture preferably contains a standard polyurethane catalyst. Examples of such catalysts include the stannous salts of carboxylic acids, such as stannous octoate, stannous oleate, stannous acetate, and stannous laureate; dialkyltin dicarboxylates, such as dibutyltin dilaurate and dibutyltin diacetate; tertiary amines and tin mercaptides. Preferably, the reaction to prepare the prepolymer is catalyzed by stannous octoate. The amount of catalyst employed is generally between 0.005 and 5 percent by weight of the mixture catalyzed, depending on the nature of the isocyanate.

IV. Adhesive Composition Preparation

The polyurethane prepolymers are present in the adhesive composition in an amount sufficient such that when the resulting adhesive cures substrates are bound together. Preferably the lap shear strengths of bonds so formed is 30 psi (206 kPa) or greater after 60 minutes and more preferably after 30 minutes. Preferably the polyurethane prepolymers are present in an amount of 55 parts by weight of the adhesive composition or greater, more preferably 60 parts by weight or greater and most preferably 69 parts by weight or greater. Preferably the polyurethane prepolymers are present in an amount of 80 parts by weight of the adhesive composition or less, more preferably 75 parts by weight or less and even more preferably 70 parts by weight or less. The isocyanate terminated polyurethane prepolymers and zeolite(s) are combined by any functionally capable means.

The adhesive of the invention may be further formulated with fillers and additives known in the prior art for use in adhesive compositions. By the addition of such materials physical properties such as viscosity flow rates and the like can be modified. However, to prevent premature hydrolysis of the moisture sensitive groups of the polyurethane prepolymer, fillers should be thoroughly dried before addition to the prepolymer.

Optional components of the adhesive of the invention include reinforcing fillers. Such fillers are well known to those skilled in the art and include carbon black, titanium dioxide, calcium carbonate, surface treated silicas, titanium oxide, fume silica, talc, and the like. Preferred reinforcing fillers comprise carbon black. In one embodiment more than one reinforcing filler may be used, of which one is carbon black and a sufficient amount of carbon black is used to provide the desired black color to the adhesive. The reinforcing fillers are used in sufficient amount to increase the strength of the adhesive and to provide thixotropic properties to the adhesive. Preferably the reinforcing filler is present in an amount of 1 part by weight of the adhesive composition or greater, more preferably 15 parts by weight or greater and most preferably 17 parts by weight or greater. Preferably the reinforcing filler is present in an amount of 40 parts by weight of the adhesive composition or less, more preferably 25 parts by weight or less and most preferably 23 parts by weight or less.

Among optional materials in the adhesive composition are clays. Preferred clays useful in the invention include kaolin, surface treated kaolin, calcined kaolin, aluminum silicates and surface treated anhydrous aluminum silicates. The clays can be used in any form which facilitates formulation of a pumpable adhesive. Preferably the clay is in the form of pulverized powder, spray-dried beads or finely ground particles. Clays may be used in an amount of 0 parts by weight of the adhesive composition or greater, more preferably 1 part by weight or greater and even more preferably 6 parts by weight or greater. Preferably the clays are used in an amount of 20 parts by weight or less of the adhesive composition and more preferably 10 parts by weight or less.

The adhesive composition of the invention may further comprise a catalyst known for promoting the cure of polyurethanes in the presence of moisture. Preferable catalysts include metal salts such as tin carboxylates, organo silicon titanates, alkyl titanates, bismuth carboxylates, and dimorpholinodiethyl ether or alkyl-substituted dimorpholinodiethyl ethers. Among preferred catalysts are bismuth octoate, dimorpholinodiethyl ether and (di-(2-(3,5- dimethylmorpholino)ethyl)) ether. Such catalysts, when employed are preferably employed in an amount based on the weight of the adhesive composition of 0 parts by weight or greater, more preferably 0.1 parts by weight or greater, even more preferably 0.2 parts by weight or greater and most preferably 0.4 parts by weight or greater. Such catalysts are preferably employed in an amount, based on the weight of the adhesive composition of 5 parts by weight or less, more preferably 1.75 parts by weight or less, even more preferably 1 part by weight or less and most preferably 0.6 parts by weight or less.

The adhesive composition of this invention may further comprise plasticizers so as to modify the rheological properties to a desired consistency. Such materials should be free of water, inert to isocyanate groups and compatible with a polymer. Suitable plasticizers are well known in the art and preferable plasticizers include alkyl phthalates such as dioctylphthalate or dibutylphthalate, partially hydrogenated terpene commercially available as “HB-40”, trioctyl phosphate, epoxy plasticizers, toluene-sulfamide, chloroparaffins, adipic acid esters, castor oil, toluene and alkyl naphthalenes. The amount of plasticizer in the adhesive composition is that amount which gives the desired rheological properties and which is sufficient to disperse the catalyst in the system. The amounts disclosed herein include those amounts added during preparation of the prepolymer and during compounding of the adhesive. Preferably plasticizers are used in the adhesive composition in an amount of 0 parts by weight or greater based on the weight of the adhesive composition, more preferably 5 parts by weight or greater and most preferably 10 parts by weight or greater. The plasticizer is preferably used in an amount of 45 parts by weight or less based on the total amount of the adhesive composition and more preferably 40 parts by weight or less.

The adhesive of this invention may further comprise stabilizers which function to protect the adhesive composition from moisture, thereby inhibiting advancement and preventing premature crosslinking of the isocyanates in the adhesive formulation. Included among such stabilizers are diethylmalonate and alkylphenol alkylates. Such stabilizers are preferably used in an amount of 0.1 parts by weight or greater based on the total weight of the adhesive composition, preferably 0.5 parts by weight or greater and more preferably 0.8 parts by weight or greater. Such stabilizers are used in an amount of 5.0 parts by weight or less based on the weight of the adhesive composition, more preferably 2.0 parts by weight or less and most preferably 1.4 parts by weight or less.

Optionally the adhesive composition may further comprise a thixotrope. Such thixotropes are well known to those skilled in the art and include alumina, limestone, talc, zinc oxides, sulfur oxides, calcium carbonate, perlite, slate flour, salt (NaCl), cyclodextrin and the like. The thixotrope may be added to the adhesive of composition in a sufficient amount to give the desired rheological properties. Preferably the thixotrope is present in an amount of 0 parts by weight or greater based on the weight of the adhesive composition, preferably 1 part by weight or greater. Preferably the optional thixotrope is present in an amount of 10 parts by weight or less based on the weight of the adhesive composition and more preferably 2 parts by weight or less.

Other components commonly used in adhesive compositions may be used in the adhesive composition of this invention. Such materials are well known to those skilled in the art and may include ultraviolet stabilizers and antioxidants and the like.

The adhesive composition of this invention may be formulated by blending the components together using means well-known in the art. Generally, the components are blended in a suitable mixer. Such blending is preferably conducted in an inert atmosphere in the absence of oxygen and atmospheric moisture to prevent premature reaction. It may be advantageous to add any plasticizers to the reaction mixture for preparing the isocyanate containing prepolymer so that such mixture may be easily mixed and handled. Alternatively, the plasticizers can be added during blending of all the components. Once the adhesive composition is formulated, it is packaged in a suitable container such that it is protected from atmospheric moisture and oxygen. Contact with atmospheric moisture and oxygen could result in premature crosslinking of the polyurethane prepolymer-containing isocyanate groups.

The adhesive composition of the invention is used to bond porous and nonporous substrates together. The adhesive composition is applied to a substrate and the adhesive on the first substrate is thereafter contacted with a second substrate. In preferred embodiments the surfaces to which the adhesive is applied are cleaned and primed prior to application; see for example U.S. Pat. Nos. 4,525,511, 3,707,521 and 3,779,794. Generally, the adhesives of the invention are applied at ambient temperature (23° C.) in the presence of atmospheric moisture. Exposure to atmospheric moisture is sufficient to result in curing of the adhesive. Curing can be accelerated by the addition of additional water or by applying heat to the curing adhesive by means of convection heat, microwave heating and the like. Preferably the adhesive of the invention is formulated to provide a working time of 6 minutes or greater, more preferably 10 minutes or greater. Preferably the working time is 15 minutes or less and more preferably 12 minutes or less.

The adhesive composition is preferably used to bond flooring to other substrates such as metal, plastics, PVC, wood, or turf. Other applications may include bonding concrete, plywood, particle or chip board, vinyl or ceramic tile and cement backer board, among other materials. Preferably the adhesive compositions of the invention demonstrate a lap shear strength after 60 minutes from application to substrates of 30 psi (206 kPa) or greater, more preferably 60 psi (412 kPa) or greater and most preferably 80 psi (548 kPa) or greater. Lap shears are determined according to ASTM D-3163. Preferably the cured adhesive compositions of the invention demonstrate an elongation of 300 percent or greater as determined according ASTM D-638-91 and preferably greater than about 600 percent. Preferably the elongation is 700 percent or less.

Viscosities are determined using a Brookfield Viscometer, Model RVT at standard conditions of 72° F. and 50% RH and using the following procedure. The viscometer is calibrated using silicone oils of known viscosities, which vary between 5,000 cps to 50,000 cps. A set of RV spindles that attach to the viscometer are used for the calibration. All measurements are done using the No. 5 spindle at a speed of 1 revolution per second for 5 minutes until the viscometer equilibrates. The viscosity corresponding to the equilibrium reading is then calculated using the calibration.

EXAMPLES

Materials

A traditional polyurethane prepolymer (Dow DIAMONDLOCK™ adhesive) may be mixed with commercially available powdered zeolite(s). A preferred, tested formulation for such a polyurethane prepolymer is listed below in Table 1. Table 2 lists the zeolite(s) utilized.

Table 1: Adhesive Formulation Table 2: List of Zeolites tested

General Protocols for Preparation and Testing

An adhesive sample that contained lwt% zeolite was placed in HS GC vials. The weighing was done in a glove box to minimize exposure of adhesive to moisture, prevent premature curing. 1 drop of water was added into the HS GC vial to promote curing and obtain conditions similar to the final flooring application.

For the tested embodiment, a 1 Qt Double Planetary Ross mixer was utilized for combining the adhesive ingredients. These ingredients include: the prepolymer (30g), SoyGold 1100 (10g) and PTSI (0.125g). The liquid mixture was mixed at 22rpm for 30 minutes under full vacuum at 50°C. The vacuum was released under nitrogen and the liquid mixture was checked for clarity.

The heating system was then removed from the mixer. Zeolites/Molecular sieves (1g) and Silica (Aerosil R202, 2g) were added and mixed for 30 minutes at 22rpm under vacuum. The vacuum was then released under nitrogen and the mixture was checked to ensure it was homogenous. Gamaco was then added (Calcium carbonate, 12.5g) to the homogenous mixture and mixed for 30 minutes, followed by the addition of CC103 (Calcium carbonate, 43.3g) the mixture being further mixed for an additional 30 mins. Once again, the vacuum was release under nitrogen and the mixture checked for homogeneity.

GLYMO epoxy silane (1g) was then added to the mixture and mixed for 20 minutes under vacuum. The vacuum was once again released under nitrogen and a sample taken for the viscosity testing. DMDEE catalyst (0.075g) was the added and mixed for 20 minutes under vacuum. The vacuum was then release under nitrogen for the final time and the material was transferred from mixer and stored for later application.

The following method and settings were utilized to analyze the adhesive samples by Headspace Gas Chromatography (GCxGC/TOFMS Method) by use of a LECO® Pegasus BT 4D GC x GC system with Liquid N ₂ Cooled Thermal Modulator:

Gas Chromatograph: Agilent 7890 equipped with a LECO thermal desorption GCxGC modulator.

Columns: Primary column: Supelco Petrocol DH, 50 m X 0.25 mm ID, 0.5 pm. Secondary column: DB-Wax, 1.5 m X 0.10 mm ID, 0.10 pm film thickness. 0.89 m is in the 2 oven, 0.20 m in GC oven, 0.10 m in modulator and 0.31 m in MS transfer line.

GCxGC Modulation: Second dimension separation time: 3 sec, hot pulse time: 0.40 sec, cool time

Between stages: 1.10 sec. Modulator temperature offset: 15 °C above the primary oven.

Carrier Gas: Helium, 1.5 mL/min with corrected constant flow via pressure ramps.

Inlet: Split injection mode, split ratio: 30: 1, temperature: 250 °C.

Injection volume: 2000 pL by Gas-Tight Syringe.

Oven Temperature

Primary GC Oven: 40 °C, 7 min, 3 °C/min to 250 °C, hold for 10 min.

Secondary Oven: +5 °C higher than oven temperature.

Modulator Temp: +15 °C higher than oven temperature.

MS: LECO Pegasus BT Time-of- Flight Mass Spectrometer.

Low Mass: 15.

High Mass: 300.

Acquisition Rate: 200 Hz.

Extraction Frequency: 30 Hz.

Electron Energy: -70 Volts.

Transfer Line: 250 °C.

Ion Source: 250 °C.

Solvent Delay: 0 minutes.

Software: ChromaTOF V5.40

For curing time determination, a BYK drying time recorder was utilized to follow the curing process of adhesive material (ASTM D-5895). Typically, a thin film (150 p) was cast on a glass substrate using ~1 mL of the mixed materials. Tack- free time of the thin film was recorded with BYK drying time recorder under 23° C and 50% RH.

For viscosity measurement, the adhesive product rheology was measured using ARES 2000 instrument equipped with a 25mm steel parallel plate and a gap of 450 p. The shear history of the sample was erased by pre-shearing the adhesive at a shear rate 100 1/s for 30 sec at 25 °C. Viscosity was measured at a steady state flow step at 25 °C isothermal temperature with a shear rate ramp from 100 Hz to 10-5 Hz.

Mechanical properties such as tensile stress, elongation at break and stress @ 100% elongation were measured according to ASTM standard test D-1708. A thin film for micro-tensile analysis was prepared by using a 25 mil draw down bar, casting the adhesive material on polypropylene substrate, and curing at room temperature for 1 week.

Results

As shown in Table 3, the adhesive formed with a high silica zeolite (Example 1) showed an enormous improvement in the reduction of volatile compounds (over 50%) versus a traditional PU adhesive (Comparative Example 1) when measure by Headspace Gas Chromatography .

Additionally, the mechanical properties of PU adhesive with zeolites incorporated were also tested under various protocols. The results of these tests can be seen in Table 4 below. As shown, there is little to no impact on the mechanical properties of a PU adhesive which has had a zeolite additive mixed in.

Table 3: GC HS Results of PU Adhesives Containing Zeolites

Table 4: Mechanical testing results of Adhesive with zeolites