The present invention is generally related to moisture-scavenging compositions, and more particularly, the invention is related to moisture- scavenging oxazolidines, ketimine alcohols and aldimine alcohols and mixtures thereof. Background Of The Art

Moisture-curable polyurethane coatings are extensively used as commercia and industrial protective and/or decorative coatings. Polyurethane coatings, known in the industry as one of the toughest coatings available, are routinely applied as protective coatings on interior and exterior walls of buildings, industrial machinery, military equipment and vehicles, commercial and passenger vehicles, and any other surface requiring a protective coating. Moisture-curable polyurethane systems are also used extensively as sealants and adhesives. Moisture-curing polyurethane coating systems include a polyisocyanate component which reacts with atmospheric water at room temperature to form useful films. These systems also include pigments, organic solvents, and a variety of adjuvant components, e.g., surface active agents, dispersants, diluents, and fillers. This type of coating is one of the finest coatings available that can be produced without the application of heat or other external sources of energy. These systems are very useful for objects that cannot be heat-cured such as buildings, large machinery, airplanes, ships and vehicles.

Since the polyisocyanate component reacts with even trace amounts of

moisture, extreme care must be taken so that the polyisocyanates do not contact

water until they are applied to a surface to be coated. Water is, however, unintentionally and unavoidably introduced into the formulation process in the form of dissolved water in solvents, adsorbed and absorbed water in fillers and pigments, and atmospheric moisture. Subsequent reaction of the water with the polyisocyanate component of the system results in an irreversible reaction which will harden the product, making it unusable before it can be applied to the

surface to be coated.

Moisture-curing polyurethane coatings are supplied as both one and two- part systems. In a two-part system, a polyol is chosen that will chemically react with and polymerize the polyisocyanate. The polyol portion generally includes a pigment. The pigmented polyol portion and the polyisocyanate portion are supplied in separate containers to the ultimate user or consumer. The consumer mixes the two portions in accordance with the ratio specified by the manufacturer just prior to use. This admixture has a limited life and must be used within a relatively short period of time or it will polymerize and become unusable in its container.

The two-part system presents several problems to the ultimate user. For example, there is a risk that the pigmented polyol portion and the polyisocyanate portion will not be mixed in the correct ratio. This could seriously detract from the performance of the resulting moisture-cured polyurethane coating. In addition, this approach is expensive in that material is wasted if the entire aclmixture is not used promptly.

Moisture-curing polyurethane coatings are also supplied as a one-part system eliminating all of the above mentioned problems of the two-part system.

In the one-part system, however, extreme care must be taken to assure that all the moisture is removed from the system prior to packaging the product; otherwise, the polyisocyanate component in the product will react with the available water and polymerize in the container. Sources of water in one-part systems include color pigments and fillers which contain absorbed and adsorbed moisture on their surfaces, water dissolved in solvents, and atmospheric moistur

This water must be removed in order to produce an acceptable product. The

existing methods for preparing color-pigmented moisture-curable polyurethane coatings in a single package require expensive equipment to dry the pigments, solvents, and fillers. In the alternative, moisture-scavenging agents are added to the preparation.

One group of moisture-scavenging compounds are the molecular sieves. Molecular sieves adsorb water into their pores, thereby binding the water and preventing it from reacting with the polyisocyanate component. An example of molecular sieve is sodium potassium aluminosilicate, available from the Mobay Corp., Pittsburgh, Pennsylvania, under the tradename designation Baylith L Powder. One disadvantage of using molecular sieves is that they reduce the glos of the cured coating. Another disadvantage of molecular sieves is that they will sometimes plasticize or embrittle the cured coating. A second group of water-scavenging agents widely used to prevent moisture-contamination of moisture-curable polyurethane coating systems is the monomeric isocyanates. A typical monomeric isocyanate, such as p- toluenesulfonyl isocyanate (Vanchem, Inc. Lockport, Connecticut), react with water to generate carbon dioxide and the corresponding sulfonamide, e.g.,

p-toluenesulfonamide. The carbon dioxide diffuses from the pigment grind duri the dehydration phase as carbon dioxide gas.

A disadvantage of monomeric isocyanates is that they are extremely corrosive to skin and toxic. In literature prepared by a supplier of monomeric isocyanates (Aldrich Chemical Co., Milwaukee, Wisconsin), monomeric isocyanates are referred to as harmful if swallowed, inhaled, or absorbed throug the skin. Moreover, these compounds are listed as extremely corrosive to the

tissues of the mucous membranes, upper respiratory tract, and skin. Symptoms monomeric isocyanate exposure include burning, coughing, nausea and vomiting, chemically induced asthma, chest pain, and pulmonary edema possibly causing death. If these compounds are to be handled by the ultimate user, the manufacturer recommends a self-contained breathing apparatus, rubber hoots an heavy rubber gloves. Since these compounds are extremely corrosive to skin and toxic, great care must be taken in their manufacture, handling, and use. This enormous health risk dramatically increases the cost of these compounds to the manufacturer and the ultimate user.

There is a need for a moisture-scavenger which efficiently, cost effectively, and safely removes water from moisture-curable polyurethane coating systems and from any other application where residual water is a problem, without seriously detracting from the performance of the cured coating.

Summary of The Invention

In order to satisfy the need for an efficient, cost effective and lower toxicity moisture-scavenger, one aspect of the present invention provides a moisture-scavenging composition including a mixture of moisture scavenging

compounds, wherein the mixture consists of from 0 to 100 mole percent of the compound:

wherein: R _x is a methyl or methylol group, an ethyl or ethylol group, a branched or straight chain alkyl or alkanol group, a cycloalkyl group, or an aryl group; R ₂

a hydrogen atom, a methyl or methylol group, an ethyl or ethylol group, a straig chain or branched chain alkyl or alkanol group, a cycloalkyl group, or an aryl group, or R _α and R ₂ are fused together with the attached carbon to form a cycloalkane ring; R ₃ , R ₄ and R ₅ are, individually, a hydrogen atom, a methyl or methylol group, an ethyl or ethylol group, or a straight chain or branched chain alkyl or alkanol group; R ₆ is a hydrogen atom, a methyl group, an ethyl group, o a straight chain or branched chain alkyl group; and R ₇ is a hydrogen atom, a methyl or methylol group, an ethyl or ethylol group, a straight chain or branched chain alkyl or alkanol group, a cycloalkyl group, an acyl group or an aryl group; and from 0 to 100 mole percent of the compound:

wherein: R _lf R ₂ , R ₃ , R ₄ , R ₅ , R ₆ and R ₇ are as defined above for compound (I).

In a preferred embodiment, the R ₇ substituents is a hydrogen atom, a

methyl group, an ethyl group, a straight chain or branched chain alkyl group, an

acyl group or an aryl group; the Rg substituent of the compounds is a hydrogen atom or a methyl group; the R ₅ substituent of the compounds is a hydrogen ato a methyl group, an ethyl group or a (C _j - C ₅ ) branched chain or straight chain alkyl group; the R ₃ and R ₄ groups are hydrogen atoms; the R _t substituent is an aryl group, an ethyl group or a ( - C _s ) branched or straight chain alkyl group; and the R ₂ substituent is a hydrogen atom, a methyl group, an ethyl group or a (C ₃ - C ₅ ) branched or straight chain alkyl group, or R _t and R ₂ are fused together with the attached carbon to form a cycloalkane ring.

A further aspect of the invention is directed to a method of dehydrating a preparation. According to the method, an effective amount of the moisture- scavenging composition including at least one of the compounds described above is mtimately admixed with the preparation. In one preferred ^p .mhndirnent, the moisture-scavenging compound is at least one of a ketimine or aldimine alcohol of compound (I) and an oxazolidine compound (II) and the effective amount of the composition includes from 1 to 3 moles of the moisture-scavenging compound for every mole of water in the preparation to be dehydrated.

The moisture-scavenging compositions of the invention can consist entirely of the moisture-scavenging compounds described above. In the alternative, the composition can include an effective amount of pigments, organic solvents, fillers, polyisocyanates and adjuvants. The amount of the moisture-scavenging compounds included in the composition is critical to the invention to the extent that the composition must include a sufficient amount of a moisture-scavenging compound to dehydrate the preparation to which it is added to, e.g., an organic solvent, or a pigment millbase preparation. Furthermore, the composition must

contain a sufficient amount of the moisture-scavenger compound to prepare anhydrous compositions useful in applications in which water is preferably avoided, e.g., moisture-curable polyurethane applications, or dehydration of surfaces onto which moisture-curable coatings are to be applied.

Brief Description Of The Drawings

FIG. 1 graphically illustrates the relative hydrolysis rates of the 2-(l- hydroxy-2-hydroxymethylbutyl)(cyclohexylidine) amine/4-ethyl-4-hydroxymethyl- l,3-oxazolidine-2-spiro-l'-cyclohexane mixture (-•-), the 2-(l-hydroxybutyl)(l- phenyl-1-ethylidine) amine/4-ethyl-2-methyl-2-phenyl-l,3-oxazolidine mixture (-+- ), the 2-(l-hydroxy-2-hydroxymethylbutyl)(l-phenyl-l-ethylidine) arnine/4-ethyl-4- hydrnxyrnethyl-2-methyl-2-phenyl-l _; 3-oxazolidine mixture (-*-). the 2-(l- hydroxybutyl)(2-heptylidine) amine/4-ethyl-2-methyl-2-pentyl-l,3-oxazolidine mixture (-D-), the 2-(l-hydroxybutyl)(5-methyl-2-hexylidine) amine/4-ethyl-2- methyl-2-(3-methylbutyl)-l,3-oxazolidine mixture (-* -), the 2-(l-hydroxy-2- hydroxymethylbutyl)(5-methyl-2-hexylidine) amine/4-ethyl-4-hydroxymethyl-2- methyl-2-(3-methylbutyl)-l,3-oxazolidine mixture (-0-), and the 2-(l- hydroxybutyl)(2,6-dimethyl-4-heptylidine) amine/2,2-(di-2-methylpropyl)-4-ethyl- 1,3-oxazohdine mixture (-Δ-);

FIG. 2 graphically illustrates the relative hydrolysis rates of the 2-(l- hydroxybutyl)(cyclohexylidine) amine/4-ethyl-l,3-oxazolidine-2-spiro-r- cyclohexane mixture (-•-), the 2-(l-hydroxybutyl)(4-methyl-2-pentylidine) amine/4-ethyl-2-methyl-2-(2-methylpropyl)-l,3-oxazohdine mixture (-*-), the 2-(l- hydroxy-2-hydroxymethylbutyl)(4-methyl-2-pentylidine) amine/4-ethyl-4-

hyα^oxymethyl-2-methyl-2-(2-methylpropyl)-l,3-oxazolidine mixture (-+-), and th

2-( l-hydroxy-2-hydroxymethylbutyl) (2-heptylidine) amine/4-ethyl-4-hydroxymethy

2-methyl-2-pentyl-l,3-oxazoUdine mixture (-□-); and

FIG. 3 graphically illustrates the relative water scavenging activity of the (l-hydroxybutyl)(4-methyl-2-pentyUdine) amine/4-ethyl-2-methyl-2-(2- methylpropyl)-l,3-oxazoUdine mixture (-•-), the 2-(l-hydroxybutyl)(l-phenyl-l- ethylidine) aπιine/4-ethyl-2-methyl-2-phenyl-l,3-oxazoUdine mixture (-+-), the 2-

(l-hydroxybutyl)(2-heptylidine) arjame/4-ethyl-2-methyl-2-penlyl-l,3-oxazoUdine mixture (-*-), the 2-(l-hydroxybutyl)(5-methyl-2-hexylidine) amine/4-ethyl-2- methyl-2-(3-methylbutyl)-l,3-oxazohdine mixture (-□-), the 2-(l-hydroxybutyl)(2,6- dimethyl-4-heptyhdine) aιnine/2,2-(di-2-methylpropyl)-4-ethyl-l,3-oxazolidine mixture (-x -) _: and the 2-(l-hydroxy-2-me±ylpropyl)(4-methyl-2-pentylidine) an ine/2-(2-methylpropyl)-2,4,4-trimethyl-l,3-oxazoUdine mixture (-0-).

Description Of The Preferred Embodiment The present invention provides a moisture-scavenging composition including a new class of moisture-scavenging compounds. The composition can be advantageously used in the formulation of specialty moisture-curable polyurethane systems, including sealants, adhesives and coatings, and in any other application in which residual water is a problem. It has been discovered that a class of compounds including ketimine and aldimine alcohols and substituted monocyclic oxazolidines are excellent moisture-scavengers. The prior art has disclosed a rather broad class of oxazolidine compounds as crosslinking reagents, reacting with polyfunctional isocyanates in the presence of polyols or water to form polymeric coatings. United States Patent No. 4,101,527 discloses an

equimolar reaction of an oxazolidine with a polyfunctional isocyanate in the presence of water to form a polyurethane coating. United States Patent No.

3,941,753 describes pre-polymers for coating formation prepared from the reaction of a ketinainoalkanol with a polyisocyanate. Bicyclic moisture scavengi oxazolidine compounds for use in formulating polyurethane coatings are disclose in copending U.S. patent application serial no. 07/624,062 by Chou, et al., entitled "Moisture Scavenging Oxazolidines", filed December 4, 1990.

The moisture-scavenging composition of the present invention includes a mixture of moisture scavenging compounds, wherein the mixture consists of fro 0 to 100 mole percent of the compound:

wherein: R _α is a methyl or d or straight chain alkyl or alkanol group, a cycloalkyl group, or an aryl group; R ₂ a hydrogen atom, a methyl or methylol group, an ethyl or ethylol group, a straig chain or branched chain alkyl or alkanol group, a cycloalkyl group, or an aryl group, or R _α and R ₂ are fused together with the attached carbon to form a cycloalkane ring; R ₃ , R ₄ and R ₅ are, individually, a hydrogen atom, a methyl or methylol group, an ethyl or ethylol group, or a straight chain or branched chain alkyl or alkanol group; R ₆ is a hydrogen atom, a methyl group, an ethyl group, o a straight chain or branched chain alkyl group; and R ₇ is a hydrogen atom, a methyl or methylol group, an ethyl or ethylol group, a straight chain or branched

chain alkyl or alkanol group, a cycloalkyl group, an acyl group or an aryl group; and from 0 to 100 mole percent of the compound:

wherein: R _l5 R ₂ , R ₃ , R ₄ , R ₅ , R ₆ and R ₇ are as defined above for compound (I). Referring to the moisture-scavenging ketimine or aldimine alcohol compounds (I) of the present invention, the preferred R group substituents are those which increase the reactivity of the compound to water. Without limiting

the invention, it has been discovered that aliphatic or aromatic R group substituents increase the reactivity of the compound to water. The moisture-

scavenging ketimine or aldimine alcohol compounds (I) of the present invention react chemically with water in the following manner:

H R R- ⁾

N H

R _ft .

0R ₇ + H20 — > ^• R ₆ c R ₅ + C

O I R ₇

As shown above, the reaction products are an amino alcohol and a carbonyl compound. One mole of moisture-scavenging ketimine or aldimine

alcohol will react with and remove one mole of water. Therefore, it is preferred that the moisture-scavenging compositions of the invention containing ketimine or

aldimine alcohols include at least one mole of the moisture-scavenging ketimine

or aldimine alcohol for each mole of water to be removed. However, since a

perfectly efficient reaction environment cannot be guaranteed in industrial

settings, it is preferable that from 1 to about 3 moles of the moisture-scavenging ketimine or aldimine alcohol be included for every mole of water to be removed.

Greater amounts of the ketimine or aldimine alcohol can be added, but are not preferred. All R group substituents which facilitate the reaction of water with the moisture-scavenging ketiminoalkanol and aldiminoalkanol compounds (I) of the present invention are preferred. In one preferred embodiment of the invention,

the R ₇ substituent is a hydrogen atom, a methyl group, an ethyl group, a straight chain or branched chain alkyl group, an acyl group or an aryl group; the R ₆ substituent of the compound is a hydrogen atom or a methyl group; the R ₅ substituent of the compound (I) is a hydrogen atom, a methyl or ethyl group, or (C ₅ - C ₅ ) branched chain or straight chain alkyl group; the R ₃ and R ₄ groups are hydrogen atoms; the R _t substituent is an aryl group, an ethyl group or a ( - C ₅ ) branched or straight chain alkyl group; and the R ₂ substituent is a hydrogen atom a methyl group, an ethyl group, or a ( - C ₅ ) branched or straight chain alkyl

group, or R-. and R ₂ are fused together with the attached carbon to form a cycloalkane ring. More preferably, the R ₁ substituent is an aryl group, an ethyl group or a ( - C ₅ ) branched or straight chain alkyl group; the R ₂ and R ₅ substituents are methyl or ethyl groups, or ( - C ₅ ) branched or straight chain alkyl groups; the R ₇ substituent is a hydrogen atom, a methyl group, an ethyl group, an acyl group or an aryl group; and the R ₆ , R ₃ and R ₄ groups are hydrogen

atoms. Most preferably, the R ₁ substituent is an aryl group or a (C ₃ - C ₅ ) branched or straight chain alkyl group; the R ₂ substituent is a methyl group, an ethyl group, or a (C ₃ - C ₅ ) branched or straight chain alkyl group; the R ₅ group is

a methyl group or an ethyl group; and the R ₇ , R ₆ , R ₃ and R ₄ groups are hydroge atoms.

Referring to the moisture-scavenging oxazolidine compounds (II) of the present invention, the preferred R group substituents are those which increase th reactivity of the ring to water. Without limiting the invention, it has been discovered that aliphatic or aromatic R group substituents increase the reactivity of the ring to water. The moisture-scavenging oxazolidine compounds (H) of the present invention react chemically with water in the following manner:

As shown above, the reaction products are an amino alcohol and a carbonyl compound. One mole of moisture-scavenging oxazoUdine compound (II) will react with and remove one mole of water. Therefore, it is preferred that the moisture-scavenging compositions of the invention containing oxazolidine compounds include at least one mole of the moisture-scavenging oxazolidine compound for each mole of water to be removed. However, since a perfectly efficient reaction environment cannot be guaranteed in industrial settings, it is preferable that from 1 to about 3 moles of the moisture-scavenging oxazolidine compound be included for every mole of water to be removed. Greater amounts of the oxazolidine compound can be added, but are not preferred.

All R group substituents which facilitate the reaction of water with the

moteture-scavenging oxazolidine compounds (EE) of the present invention are

^"

preferred. In one preferred embodiment of the invention, the R ₇ substituent of the compound (II) is a hydrogen atom, a methyl group, an ethyl group, a straigh chain or branched chain alkyl group, an acyl group or an aryl group; the R^ substituent of the compound is a hydrogen atom or a methyl group; the R ₅ substituent of the compound is a hydrogen atom, a methyl or ethyl group, or a

(C _j - C ₅ ) branched chain or straight chain alkyl group; the R ₃ and R ₄ groups are hydrogen atoms; the R _t substituent is an aryl group, an ethyl group or a (C ₃ -

branched or straight chain alkyl group; and the R ₂ substituent is a hydrogen ato a methyl group, an ethyl group, or a ( - C ₅ ) branched or straight chain alkyl group, or R ₁ and R ₂ are fused together with the attached carbon to form a

cycloalkane ring. More preferably, the R _x substituent is an aryl group, an ethyl group or a (C _j - C ₅ ) branched or straight chain alkyl group: the R ₂ and R ₅ substituents are methyl or ethyl groups, or ( - C ₅ ) branched or straight chain alkyl groups; the R ₇ substituent is a hydrogen atom, a methyl group, an ethyl group, an acyl group or an aryl group; and the R ₆ , R ₃ and R ₄ groups are hydroge atoms. Most preferably, the R-* substituent is an aryl group or a ( - C ₅ ) branched or straight chain alkyl group; the R ₂ substituent is a methyl group, an ethyl group, or a (C ₃ - C ₅ ) branched or straight chain alkyl group; the R ₅ group is a methyl group or an ethyl group; and the R ₇ , R ₆ , R ₃ and R ₄ groups are hydroge atoms.

The structure of the R substituents in either the ketiminoalkanols, aldiminoalkanols or monocyclic oxazolidines is determined by the selection of the reactant precursor compounds. Reaction of a primary amino alcohol with a carbonyl compound produces an equilibrium mixture of an oxazolidine compoun

(II) along with its tautomeric iminoalcohol compound (I) as confirmed by JLR spectral data. The amount of each compound present in the equilibrium mixtur varies depending on the R substituents. Bulky substituents at R-* and R ₂ , as well as substitution at R ₃ and R ₄ will generally shift the equilibrium to the iminoalcohol compound (I), although the compounds of the present invention ar not limited thereto. In a specific embodiment of the invention, the 2-(l- hydroxybutyl) (4-methyl-2-pentylidine) amine/4-ethyl-2-methyl-2-(2-methylpropyl)

1,3-oxazolidine iminoalcohol-oxazolidine mixture is prepared by reacting D,L-2- amino-1-butanol with methyl isobutyl ketone. Detailed protocols for synthesizing several preferred moisture-scavengers of the present invention are described herein.

A further nsnect nf the invention is directed to a method of dehvdratine a preparation. In one embodiment the preparation includes at least one pigment and at least one organic solvent. According to the method, an effective amount of the composition of the invention including a ketimine or aldimine alcohol and/or a monocyclic oxazolidine moisture-scavenging compound as described above is intimately admixed with the preparation. In a preferred embodiment, the effective amount includes from 1 to about 3 moles of a mixture of a ketimine or aldimine alcohol compound (I) and an oxazolidine compound (II) for every mole of water in the preparation to be dehydrated.

According to one embodiment of the invention, catalysts are added in combination with the moisture-scavenging iminoalcohol-oxazolidine mixtures of the present invention to facilitate the reaction with water. The addition of a

preferred catalyst will, in some instances, minimize the amount of the

iminoalcohol-oxazolidine mixture required to remove water from a preparation increasing the efficiency of the reaction. Furthermore, a preferred catalyst will, certain circumstances, increase the rate at which the moisture-scavenging compounds react with water. Preferred catalysts include the organometallic catalysts, such as dibutyltin laurate, the mineral acid catalysts and the organic a catalysts, such as acetic acid.

According to another embodiment of the invention, the reaction between

the moisture-scavenging compounds and water occurs at temperatures from ambient to about the boiling point of the preparation being dehydrated. Preferably, this range is from about 40 to about 180 degrees Fahrenheit.

Increasing the temperature at which the reaction occurs increases the rate and the efficiency of the reaction.

The moisture-scavenging compounds of the present invention are advantageously used in urethane coating, sealant and adhesive systems to remov moisture during the formulation, packaging and application steps. The present invention provides the producer of specialty polyurethane systems with an expedient and efficient alternative to the physical methods of dehydration, exemplified by molecular sieves and drying machinery, and the potentially toxic prior chemical methods, exemplified by the monomeric isocyanates presently available. The moisture-scavenging compositions of the present invention are further provided for the storage stabilization of moisture-curable polyurethane systems. A still further intended use of the invention is the dehydration of surfaces onto which moisture-curable coatings are to be applied.

The invention provides an anhydrous composition including the moisture-

scavenging compounds described above and an organic solvent. Solvents used in the formulation of one and two-component systems are rapidly dehydrated by treating them with the moisture-scavenging composition of the invention. This anhydrous composition is useful in any appHcation where water is preferably avoided, e.g., preparing moisture-curable polyurethane coatings, or dehydrating surfaces prior to applying moisture-curable coatings. The quantity of moisture- scavenger in the composition will vary with the water content of the solvent. The amount of water in the organic solvent being dehydrated can be determined by gas chromatography. The solvents generally used in the formulation of specialty polyurethane systems are compatible with the moisture-scavenging compositions of the present invention. Solvents generally used in the preparation of

polyurethane moisture-scavenging preparations include aprotic solvents, such as ketones, esters, ethers, mtroparaffins, glycol esters, glycol ether esters, halogenated hydrocarbons, and alkyl and aromatic hydrocarbons.

Pigments, fillers, polyisocyanates, and adjuvants are suspended in organic solvents. For the purposes of this invention the term "fillers" is intended to include those materials added to a coating preparation to increase the solids content of the coating. The term "adjuvants" is intended to include those materials which are added to the coating formulation to aid application or formation, such as surface active agents, anti-settling agents, diluents, suspending agents and the like. Pigments, fillers, polyisocyanates and adjuvants can also be dehydrated with the water-scavenging compositions of the present invention.

One aspect of the present invention is a substantially anhydrous composition including pigments, fillers, organic solvents, and the moisture- scavenging compounds described above. It has been determined that a reaction period of from 30 minutes to about twenty-four hours is preferred to ensure substantially complete dehydration of pigment preparations. The amount of the moisture-scavenger composition required to dehydrate the pigment or filler will vary with the total water content. Through the addition of the moisture-

scavenging composition of the invention, an anhydrous composition is produced including pigments, organic solvent(s), fillers, polyisocyanates and adjuvants. Alternatively, any of the above-listed components can be deleted, depending on the needs of the ultimate user. This anhydrous composition is useful in applications where water is preferably avoided, e.g., in the formulation of moisture-curable polyurethane coatings.

The following examples are presented to describe preferred embodiments and utilities of the present invention and are not meant to limit the present invention unless otherwise stated in the claims appended hereto. Each of the equilibrium mixtures is referred to in the examples by the name of the iminoalcohol compound present in the mixture. These iminoalcohol compounds and their corresponding oxazolidines which form equilibrium mixtures are listed in the table below.

Table 1; Iminoalcohol-Oxazolidine Mixtures of the Present Invention

EXAMPLES

Example 1: Preparation of 2-( -Hvdroxybutylι ( ^" cyclohexylidine ^' , amine/4-Ethyl- U-oxazolidine^-spiro-l'-cvclohexane Mixture

D,I _^ 2-Arnino-l-butanol (AB®) (133.7 grams; 1.5 mol.) was added to a 3- neck, 500 ml round bottom flask equipped with a magnetic stir bar, a 250 ml addition funnel, a thermometer, and a Dean-Stark trap (50 ml capacity). While stirring, cyclohexanone (161.9 grams; 1.6 mol.) was added over a ten minute period resulting in an exothermic reaction (26°C →65°C). The reaction mixture was heated to reflux and 24 grams of water were collected in the Dean-Stark tra

over a two hour period. The product was purified by vacuum distillation (77-78°

@ 3.5 mm Hg) using a mirrored column (250mm x 10 mm i.d.) packed with metal helixes. The material was stored under a nitrogen ntmnspherfi.

Example 2: Preparation of 2-d-Hydroxy-2-hvdroxymethvIbutyl ^' .(cyclohexylidine amine^-EthyM-hvdroxymethyl-lJ-oxazolidine-Z-spiro-l- ¹ - cyclohexane Mixture

2-Amino-2-ethyl-l, 3-propanediol (AEPD ^® ) (178.9 grams; 1.3 mol.) was added to a 3-neck, 1 liter round bottom flask equipped with a mechanical stirrer, a 500 ml addition funnel, a thermometer, and a Dean-Stark trap (100 ml capacity). While stirring, cyclohexanone (309.1 grams; 3.1 mol.) was added over seven minute period causing a lower reaction mixture temperature. The reaction mixture was heated to reflux and 25 grams of water were collected in the Dean- Stark trap over a two hour period. The product was purified by vacuum distillation (121°C-123°C @ 2mm Hg) using a mirrored column (250 rnm x 10 m i.d.) packed with metal helixes. The material was stored under a nitrogen atmos

Example 3: Preparation of 2-(l-Hydroxybutyl)(4-methyl-2-pentylidine) amine/ Ethyl-2-methyl-2-(2-methylpropyD-1.3-oxazolidine Mixtnre

D,I^2-Amino-l-butanol (AB ^® ) (133.7 grams; 1.5 mol.) was added to a 3- neck, 500 ml. round bottom flask equipped with a magnetic stir bar, a 250 ml addition funnel, a thermometer, and a Dean-Stark trap (50 ml capacity). While stirring, 4-methyl-2-pentanone (MTBK) (165.3 grams; 1.6 mol.) was adde over a three minute period causing a lower reaction mixture temperature.

(20°C→17°C). The reaction mixture was heated to reflux and 25 grams of water were collected in the Dean-Stark trap over a six hour period. The crude produc was purified by vacuum distillation (91°C @ 14 mm Hg) using a mirrored colum

(250mm x 10mm i.d.) packed with metal helixes. The material was stored under a nitrogen atmosphere.

Example 4: Preparation of 2-d-Hydroxy-2-hydroxymethylbutyl>(4-methyI-2- pentylidine) amine/4-Ethyl-4-hydroxymethvI-2-methyl-2-f2- methylpropylVl. 3-oxazolidine Mixture

2-Amino-2-ethyl-l,3-propanediol (AEPD ^® ) (179.3 grams; 1.3 mol.) was added to a 3-neck, i liter round bottom flask equipped with a mechanical stirrer, a 500 ml addition funnel, a thermometer, and a Dean-Stark trap (100 ml capacity). While stirring, 4-methyl-2-pentanone (MTBK) (315.7 grams; 3.1 mol.) was added over a three minute period causing the reaction mixture temperature to lower by 1°C. The reaction mixture was heated to reflux and 24 grams of water were collected in the Dean-Stark trap over a fifty-five hour period. The

crude product was purified by vacuum distillation (107°C-109°C @ 2 mm Hg) using a mirrored column (250mm x 10 mm id.) packed with metal helixes. The material was stored under a nitrogen atmosphere.

Example 5; Preparation of 2-fl-HvdroxyburvI)(l-phenyl-l-ethylidine) amine/4 Ethyl-2-methyl-2-phenyI-1.3-oxazolidine Mixture

D,L-2-Amino-l-butanol (AB ^® ) (133.7 grams; 1.5 mol.) was added to a 3- neck, 500 ml round bottom flask equipped with a magnetic stir bar, a 250 ml. addition funnel, a thermometer, and a Dean-Stark trap (50 ml capacity). While

stirring, acetophenone (198.3 grams; 1.6 mol.) was added over a five rninute period causing a lower reaction mixture temperature (21°C-*18°C). The reactio rnixture was heated to reflux and 26 grams of water were collected in the Dean- Stark trap over a twenty hour period. The crude product was purified by a vacuum distillation (95-99°C @ 2-3 mm Hg) using a mirrored column (250mm x 10mm i.d.) packed with metal helixes. The material was stored under a nitroge

atmosphere.

Example 6: Preparation of 2-d-Hvdroxy-2-hydroxymethylbutyl ^' )fl-phenyl-»l- ethylidine) amine/4-Ethyl-4-hvdroxymethyl-2-methyl-2-phenyl-1 - oxazolidine Mixture

2-Amino-2-ethyl-l,3-propanediol (AEPD ^® ) (179.4 grams; 1.3 mol.) was added to a 3-neck, 1 liter round bottom flask equipped with a mechanical stirrer, a 500 ml addition funnel, a thermometer, and a Dean-Stark trap (100 ml capacity). While stirring, acetophenone (378.7 grams; 3.1 mol.) was added over an eight minute period causing a three degree lowering in the reaction mixture temperature. The reaction mixture was heated to reflux and 20 grams of water were collected in the Dean-Stark trap over a twenty hour period. The crude product was purified by vacuum distillation (114°C *→120°C @ 0.9-1.0 mm Hg) using a mirrored column (250 mm x 10 mm i.d.) packed with metal helixes. The material was stored under a nitrogen atmosphere.

Example 7: Preparation of 2-(l-Hydroxybutyl)(2-heptylidine) amine/4-EthyI-2- methyl-2-penryl-l 3-oxazoIidine Mixture

D,L-2-amino-l-butanol (AB ^® ) (133.7 grams; 1.5 mol.) was added to a 3-

neck, 500 ml round bottom flask equipped with a magnetic stir bar, a 250 ml addition funnel, a thermometer, and a Dean-Stark trap (50 ml capacity). While stirring, 2-heptanone (MAK) (188.3 grams; 1.6 mol.) was added over a three minute period causing a lowering of the reaction mixture temperature

(24°C→20°C). The reaction mixture was heated to reflux and 24 grams of water were collected in the Dean-Stark trap over a thirteen hour period. The crude product was purified by vacuum distillation (70-73°C @ 0.8-1.0 mm Hg) using a rnirrored column (250 mm x 10mm i.d.) packed with metal helixes. The material was stored under a nitrogen atmosphere.

Example 8: Preparation of 2-f l-Hydroxy-2-hydroxymethylbutyOf2-heptylidine ^' , amine/4-EthvI-4-hydroxymethvI-2-methyI-2-Dentyl-1 OxazoIidine Mixture

2-Amino-2-ethyl-l,3-propanediol (AEPD ^® ) (179.3 grams; 1.3 mol.) was added to a 3-neck, 1 liter round bottom flask equipped with a mechanical stirrer, a 500 ml addition funnel, a thermometer, and a Dean-Stark trap (100 ml capacity). While stirring, 2-heptanone (MAK) (359.6 grams; 3.1 mol.) was added over a five minute period causing a two degree temperature drop in the reaction mixture temperature (24°C— >22°C). The reaction mixture was heated to reflux and 26 grams of water were collected in the Dean-Stark trap over a thirteen hour period. The crude product was purified by vacuum distillation (97°C-98°C @ 1.0

mm Hg) using a mirrored column (250 mm x 10 mm i.d.) packed with metal helixes. The material was stored under a nitrogen atmosphere.

Example 9: Preparation of 2-(l-HydroxybutyD(5-methyl-2-hexylidine) amine/4 Ethyl-2-methyl-2-f3-methylbutvn-1.3-oxazoIidine Mixture

D,I^2-Amino-l-butanol (AB ^® ) (133.7 grams; 1.5 mol.) was added to a 3- neck, 500 ml round bottom flask equipped with a magnetic stir bar, a 250 ml addition funnel, a thermometer, and a Dean-Stark trap (50 ml capacity). While

stirring, 5-methyl-2-hexanone (MIAK) (188.4 grams; 1.6 mol.) was added over a four minute period causing a four degree lowering of the reaction mixtur temperature (22°C- _* 18°C). The reaction mixture was heated to reflux and 21 grams of water were collected in the Dean-Stark trap over a twelve hour period. The crude product was purified by vacuum distillation (46-48°C @ 03 mm Hg) using a mirrored column (250 mm x 10mm i.d.) packed with metal helixes. The material was stored under a nitrogen atmosphere.

Example 10: Preparation of 2-(l-Hydroxy-2-hydroxymethylbutyl>(5-methyl-2- hexylidine) amine/4-Ethyl-4-hydroxymethyl-2-methyl-2-(3- methylbutyπ-1 -oxazolidine Mixture

2-Amino-2-ethyl-l,3-propanediol (AEPD ^® ) (179.3 grams; 1.3 mol.) was added to a 3-neck, 1 liter round bottom flask equipped with a mechanical stixrer, a 500 ml addition funnel, a thermometer, and a Dean-Stark trap (100 ml capacity). While stirring, 5-methyl-2-hexanone (MIAK) (360.0 grams; 3.1 mol.) was added over a three minute period causing a one degree temperature drop in the reaction mixture temperature (22°C->21°C). The reaction mixture was heate to reflux and 25 grams of water were collected in the Dean-Stark trap over a ten hour period. The crude product was purified by vacuum distillation (98-99°C @ 0.3 mm Hg) using a mirrored column (250 mm x 10 mm i.d.) packed with metal helixes. The material was stored under a nitrogen atmosphere.

Example 11: Preparation of 2-(l-Hydroxybuty0f2.6-dimethyl-4-heptylidine ^' » amine/2.2-fDi-2-methylpropyl)-4-ethyI-1 -oxazolidine Mixture

D,Lz-2- Amino- 1-butanol (AB ^® ) (133.7 grams; 1.5 mol.) was added to a 3- neck, 500 ml round bottom flask equipped with a magnetic stir bar, a 250 ml addition funnel, a thermometer, and a Dean-Stark trap (50 ml capacity). While stirring, 2,6-dimethyl-4-heptanone (DEBK) (234.7 grams; 1.3 mol.) was added over a two minute period causing a three degree lowering of the reaction m ture temperature (24 ⁰ C→21°C). The reaction mixture was heated to reflux and 24 grams of water were collected in the Dean-Stark trap over a twenty hour period. The crude product was purified by vacuum distillation (95-99°C @ 1.5-1. mm Hg) using a mirrored column (250 mm x 10 mm id.) packed with metal helixes. The material was stored under a nitrogen atmosphere.

Example 12: Preparation of 2-f l-Hydroxy-2-methylpropyO(4-methyl-2- pentylidine) amine/2-(2-Methylpropyl ^' l-2.4.4-trimethyl-l,3- oxazolidine Mixture

2-Aniino-2-methyl-l-propanol (AMP™) (133.7 grams; 1.5 mol.) was added to a 3-neck, 500 mi round bottom flask equipped with a magnetic stir bar, a 250 ml addition funnel, a thermometer, and a Dean-Stark trap (50 ml capacity). The flask was warmed to 45 ^C C to melt the AMP. While stirring, 4-methyl-2-pentanone (MEBK) (165.3 grams; 1.6 mol.) was added over a five minute period and the mixture was heated to reflux. After thirty-five hours, 23 grams of water were collected in the Dean-Stark trap. The crude product was purified by vacuum distillation (36°C @ 1.1mm Hg) using a mirrored column (250 mm 10mm i.d.) packed with metal helixes. The material was stored under a nitrogen atmosphere.

Example 13: Preparation of 2-d3-Dihydroxy-2-methylpropyDf4-methyl-2- pentylidine) amine/4-Hydroxymethyl-2.4-dimethyl-2-(2- methylpropyl-13-oxazolidine Mixture

2-Arnino-2-methyl-l,3-propanediol (AMPD™) (157.7 grams; 1.5 mol.) was added to a 3-neck, 1 liter round bottom flask equipped with a mechanical stirrer, a 500 ml addition funnel, a thermometer, and a Dean-Stark trap (100 ml capacity). The flask was warmed to 115°C to melt the AMPD. While stirring, 4- methyl-2-pentanone (MIBK) (180.3 grams; 1.8 mol.) was added gradually over a

twenty-two minute period to prevent lowering the temperature and precipitation of the AMPD. The mixture was heated to reflux and after twenty-six hours, 24 grams of water were collected in the Dean-Stark trap. The crude product was purified by vacuum distillation (95°C-100°C @ 1.8-2.0 mm Hg) using a mirrored column (250 mm x 10 mm id.) packed with metal helixes. The material was stored under a nitrogen atmosphere.

Example 14: Water Hydrolysis Comparison Study

The appropriate amount of an iminoalcohol-oxazolidine mixture (0.02 mol.) was added to a 100 ml volumetric flask and was diluted with some acetonitrile. Five equivalents of water (0.10 mol., 1.8 grams) and a 10 mole % catalyst load of acetic acid based on the iminoalcohol-oxazolidine rnixture (0.002 mol, 0.12 grams) were added to the solution. The solution was then diluted to the mark on the volumetric flask with acetonitrile. The amount of iminoalcohol- oxazolidine mixture, acetic acid and water for each solution that was prepared are listed below in Table 2.

Table 2.

After the solution was prepared, samples of the solution were held at 60° and monitored by gas chromatography every twenty-four minutes for the iminoalcohol-oxazolidine mixture, amino alcohol and ketone content over an eight hour period. A normalized gas chromatographic area count was determin for the above three components. A potential water scavenger candidate was deterrnined by the decrease in iniinoalcohol-oxazolidine mixture content with a corresponding appearance of the amino alcohol and ketone content. A graphica representation of the data is made by plotting the normalized peak areas of iminoalcohol, oxazolidine, amino alcohol, and ketone versus time (minutes). Relative hydrolysis rates of most of the above listed iminoalcohol- oxazolidine mixtures are compared in FIGS. 1 and 2 which show the normalized peak areas of the oxazolidine versus time. The 2-(l-hydroxybutyl)(4-methyl-2-

pentylidine) amine mixture, 2-(l-hydroxybutyl)(2,6-dimethyl- -heptyUdine) amine mixture, 2-(l-hydroxybutyl)(2-heptylidine) amine mixture, 2-(l-hydroxybutyl)(5- methyl-2-hexylidine) amine mixture and 2-(l-hydroxybutyl)(l-phenyl-l-ethyh ^' dine) amine mixture are shown to have greater hydrolysis rates than the other iminoalcohol-oxazolidine mixtures which were considered. The iminoalcohol- oxazolidine mixture having the most preferred hydrolysis rate is the 2-(l- hydroxybutyl)(4-methyl-2-pentylidine) amine mixture.

Example 15: Comparison of Water Scavenging Activity

The appropriate amount of an iminoalcohol-oxazolidine mixture (0.02 mol.) was added to a 100 ml volumetric flask and diluted with some acetonitrile.

A half an equivalent of water (0.01 mol., 0.18 gram) and a 10 mole % catalyst

load of acetic acid (0.002 mol., 0.12 gram) were added to the solution. The solution was then diluted to the mark on the volumetric flask with acetonitrile.

The amount of iπύnoalcohol-oxazolidine mixture, acetic acid and water for each solution that was prepared are listed below in Table 3.

Table 3

After the solution was prepared, samples of the solution were held at 25°C and monitored by gas chromatography for the iminoalcohol, oxazoUdine, ami-no alcohol and ketone and water content over a six hour period. The concentrations (moles/Uter) of the above six materials were monitored as a function of time to determine if a particular iminoalcohol-oxazolidine mixture showed water scavenging activity. The relative water scavenging rates are illustrated in FIG. 3 which illustrates the water concentration as a function of time. The 2-(l-

hydroxybutyl)(4-methyl-2-pentylidine) amine mixmre, 2-(l-hydroxybutyl)(5-methyl-

2-hexyUdine) amine mixture and 2-(l-hydroxybutyl)(2-heptylidine) amine mixture were shown to be the most effective moisture scavengers.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example and were herein described in detail. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives

falling within the spirit and scope of the invention as defined by the appended claims. Any R group substituents which increase the reactivity of a moisture scavenging compound of the present invention to water are within the scope of the present invention. For example, alkenyl and alkynl groups may be selected a

R group substituents if these groups increase the reactivity of a moisture scavenging compound to water. Likewise, any substituted R groups which

increase the reactivity of the moisture-scavenging compounds to water may be included in the compounds of the present invention.