POLYMERIZATION OF BICYCLIC AMIDE ACETALS AND POLYISOCYANATES IN THE PRESENCE OF MOISTURE

Abstract: A process for the preparation of novel polymeric pro­ ducts which involves the reaction of mixtures of bicyclic amide acetals and polyisocyanates with moisture is de­ scribed.

Description: Bicyclic amide acetals and their manufacture are described in Synthesis, 1971, page 16 et seqq.. DE-A-3235933 discloses a process for the production of bicyclic orthoester amides (bicyclic amide acetals) and their suitability as chain extenders and cross linking agents in the polyurethan field. The reaction of an isocyanate pre-polymer with a bicyclic amide acetat carried out at elevated temperatures (150°C) to give a cross-linked polymer product is described in Example 6 thereof. This invention relates to the process for the preparation of useful polymers by reaction of bicyclic amide acetals and polyisocyanates in the presence of moisture at about room temperature. Bicyclic amide acetals have been hydrolyzed with an excess of water in Ann. Chem. 716, 135(1968). The use of mixtures of bicyclic amide acetals and polyisocyanates in moisture-cure systems has not been described previously. It has been discovered that mixtures of bicyclic amide acetals and polyisocyanates will polymerize in the presence of moisture at about room temperature to produce valuable polymers useful as coatings or adhesives. The polymerization which occurs in this process is particularly advantageous in that no volatile materials are produced during the polymerization reaction so that under normal conditions no foaming or bubble formation occurs. This is highly desirable in the case in which the polymerization process is used to produce coatings. The bicyclic amide acetals useful in the process of this invention are those which conform to the formula (I). wherein R is a hydrocarbon group having from 1 to 18 carbon atoms and preferably an alkyl group having from 1 to 18 carbon atoms or an aryl or alkaryl group having from 6 to 12 carbon atoms; R' can be independently selected and represents hydrogen, a hydrocarbon group having from 1 to 18 carbon atoms or an ether group having from 2 to 18 carbon atoms; and R" represents hydrogen, a hydrocarbon group having from 1 to 18 carbon atoms, or an ether group having from 2 to 18 carbon atoms. The polyisocyanates useful in the process of the invention are those isocyanate compounds which contain at least two isocyanate groups per molecule and included in this group are monomeric, oligomeric and polymeric isocyanate compounds which comply with the foregoing requirement. Polyisocyanates useful in this invention are organic isocyanates having at least two isocyanate groups per molecule. The polyisocyanates can be of low, high or intermediate molecular weight and can be any of a wide variety of organic polyisocyanates including ethylene disocyanate, trimethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate trimer, tetraethylene diisocyanate, pentamethylene diisocyanate, propylene-1,2-diisocyanate, 2,3-dimethyl tetramethylene diisocyanate, butylene-1,2-diisocyanate, butylene-1,3-diisocyanate, 1,4-diisocyanato cyclohexane, cyclopentane 1,3-diisocyanate, p-phenylene diisocyanate, 1-methyl phenylene-2,4-diisocyanate, naphthalene-1,4-diisocyanate, toluene diisocyanate, diphenyl-4,4'-diisocyanate, benzene-1,2,4-triisocyanate, xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate, 4,4'-diphenylene methane diisocyanate, 4,4'-diphenylene propane diisocyanate, 1,2,3,4-tetraisocyanato butane, butane-1,2,3-triisocyanate, polymethylene polyphenyl isocyanate, and other polyisocyanates having an isocyanate functionality of at least two as more fully disclosed in US-A-3,350,362 and 3,382,215. Polyisocyanates which are polymeric in nature including isocyanate prepolymers or all types are included in this invention. The process of this invention is carried out at about room temperature. Although a catalyst is not required in the process of this invention, it is sometimes desirable to use a catalyst such as an amine, an amino alcohol, a metal salt such as dibutyl tin dilaurate or stannous octoate. The amount of moisture required for the polymerization reaction of this invention can vary from just a trace to an equal molar amount in respect to the bicyclic amide acetal used in the process. Although the exact mechanism of the reaction involved in the process of this invention is not known with any degree of certainty, it is possible that the bicyclic amide acetal reacts with moisture to form the corresponding amide diol wherein R, R' and R" have the foregoing designations which amide diol then reacts with the isocyanate groups to form polymeric polyamide-polyurethane materials. The amide diol itself may possibly act as a promoter in the polymerization reaction of this process. The invention is further illustrated in the following examples. EXAMPLE 1 A mixture of 4.3g of a bicyclic amide acetal (Formula I, R=-CH₂CH₃, R'=-H, R"=-CH₂OCH₂CH=CH₂) and 8.4g of hexamethylene diisocyanate trimer was applied to a clean glass plate as a 0,0254mm (1 mil) thick film. The film was allowed to stand at room temperature in the open atmosphere for two days during which it cured to give a clear, colorless film. The following tests were performed. EXAMPLE 2 The procedure of Example 1 was repeated except that one drop of dibutyltin dilaurate was added to the mixture prior to applying it to the glass plate. The resulting film was found to cure within 5 hours and tests on the film showed results similar to those of Example 1. EXAMPLE 3 The procedure of Example 2 was repeated except that R" in Formula I was -C₆H₅. Results similar to those in Example 2 were obtained. EXAMPLE 4 The procedure of Example 1 was followed using 2.15g of the bicyclic amide acetal, 7.30g of a mixture of toluene disocyanate and hexamethylene diisocyanate trimer and a drop of a tertiary amine catalyst in the mixture. A film of 0,0508mm (2 mils) thickness was applied to a clean glass plate and overnight cure at room temperature in the open atmosphere produced a tough film which was not affected by exposure to methyl ethyl ketone, toluene, water or 5% aqueous NaOH.

Claims: A process for producing a cured polymeric material, characterized in that a bicyclic amide acetal of formula I wherein R is a hydrocarbon group having from 1 to 18 carbon atoms and R' can be independently selected and represents hydrogen, a hydrocarbon group having from 1 to 18 carbon atoms or an ether group having from 2 to 18 carbon atoms; and R" represents hydrogen, a hydrocarbon group having from 1 to 18 carbon atoms or an ether group having from 2 to 18 carbon atoms is mixed with a polyisocyanate compound having at least two isocyanate groups per molecule and the resulting mixture is allowed to react in the presence of moisture at about room temperature. The process of Claim 1 wherein the moisture present is from just a trace up to an equal molar amount based on the moles or bicyclic amide acetal present. The process of Claim 2 wherein there is also included a catalyst. The process of Claim 2 wherein R is -CH₂CH₃ and R" is -CH₂OCH₂CH=CH₂ The process of Claim 2 wherein R is -CH₂CH₃ and R" is -C₆H₅. The process of Claim 3 wherein the catalyst is a tertiary amine. The process of Claim 3 wherein the catalyst is dibutyl tin dilaurate. The process of Claim 2 wherein the polyisocyanate is hexamethylene diisocyanate trimer. The process of Claim 2 wherein the polyisocyanate is a mixture of toluene diisocyanate and hexamethylene diisocyanate trimer.

Inventors: GOEL, ANIL B.
Applicants: ASHLAND OIL, INC.
Application year: 1985
Main classification: C08G18
IPC codes: C08G18