IMPROVEMENTS RELATING TO POLYURETHANE CATALYSTS

Abstract: Delayed action catalyst systems, principally for polyurethane production, of improved shelf life with greater potential for process control comprise: (i) a compound of the formula: (FORMULA) wherein: Q and Q' which may be the same or different, each represent C<u1>u to C<u10>u alkylene, C<u2>u to C<u10>u alkenylene or an arylene group; R<u1>u, R<u2>u, R<u3>u and R<u4>u which may be the same or different, each represent a substituted or unsubstituted alkyl group; and x represents zero or an integer less than 6; and (ii) an amine.

Description: IMPROVEMENTS RELATING TO POLYURETHANE CATALYSTS This invention relates to improved catalysts for the production of polyesters and polyurethanes. In our OLS 2821306 we have described and claimed compounds of the formula: R OOCQCOO - Sn J (_0 wherein: Q and Q* which may be the same or different, each represent a group of the formula -j (-CH η \— or an arylene group; R , R , R and R. , " which may be the same or different, each represent a substituted or unsubstituted alkyl group; n represents zero or an integer from 1 to 10, and x represents zero or an integer less than 6. Such compounds are delayed action catalysts for polyester and polyurethane production. We have now determined that delayed action catalyst systems of improved shelf life with greater potential for process control comprise: (i) a compound of the formula: wherein: Q and Q' , which may be the same or different, each represent a C to C alkylene, C to C alkenylene or an arylene group; R , R , R and R. , which may be the same or different , each represent a substituted or unsubstituted alkyl group; and x represents zero or an integer less than 6 ; and (ii ) an amine . OMPI /,. IPO - 2 - Component (ii) of the catalyst system is suitably a tertiary amine, preferably one of the formula: wherein: R , R,, R , which may be the same or different, each 5' 6' 7 represent a C to C alkyl group, for example an ethyl group. Triethylamine is found to be a convenient tertiary amine for use as component (ii). In the above formulae R , R , R or R, suitably represents an unsubstituted alkyl group, for example a C to C,. alkyl group, preferably a C to C, alkyl group. Generally, R and R will be 1 At 3. £Λ identical and it is particularly preferred that they both represent butyl groups. Suitably, R and R, will be identical. It is preferred that R and R, both represent a methyl or an ethyl group. Q and Q 1 , are preferably identical, most preferably a C to C, linear alkylene group. Preferably, x represents an integer less than 4, especially 1. It is believed that when x = 1, and possibly when x > 1, these compounds exist in an associated form. When x = 1, the structure may be a dimer of the formula: It is not known whether, at the low concentrations encountered in polyurethane-forming reactions, these compounds are associated or not. Preferred delayed action catalyst systems of the invention are those in which one or, most preferably, both of R and of Q (R and R, being identical and Q and Q' being identical) are C to C, moieties. Examples include the derivatives of ethyl O F / λ . WIF - 3 - adipate half ester, methyl glutarate half ester and methyl succinate half ester, especially methyl glutarate half ester and methyl succinate half ester. Preferably the weight ratio (i):(ii) is from 0.80:1 to 1.20:1. The above mentioned compositions of the invention are delayed action catalyst systems for the production of polyurethane. Component (i) of the catalyst systems of the invention may be prepared in accordance with the disclosure of our OLS 2821306. It is particularly preferred that the reagents are anhydrous; for example the organic solvent is preferably sodium-dried. This invention also provides a delayed action process for the preparation of a polyurethane, which process comprises introducing a polyol and a pol isocyanate into a reaction vessel in the presence of a delayed action catalyst system as herein described; forming a homogeneous mixture of the reactants and catalyst system prior to polymerisation; and allowing the homogeneous mixture to polymerise to a polyurethane. Such a process is, however, strongly temperature dependent. Thus, with the preferred catalyst systems of the invention, for example those derived from methyl glutarate half ester or methyl succinate half ester, it is highly desirable that the initial temperature of the homogeneous mixture is not greater than 30 C, preferably from 20 C to 25 C; if the initial temperature is higher, there is a possibility that the catalyst system will immediately be activated and no delay period observed. However, for less active catalyst systems of the invention, such as those claimed from n-dodecyl succinate half ester, excellent results may be attained by using an initial temperature of 40 C to 50 C for the homogeneous mixture. Broadly speaking, the selection of catalyst component (i) will depend on the desired initial temperature of the homogeneous mixture, the reactant bulk, and, OMPI - 4 - to a lesser extent, reactor geometry and composition. This may readily be determined by routine experiment by one skilled in the art. The catalyst systems of this invention may also be used at higher temperatures at which no delay period is observed. Once catalyst component (i) has been selected, it is possible to optimise the system (a) by the amount of (i) present and (b) by the weight ratio (i):(ii) present, thereby giving great control over the process of this invention. Thus, in general, it is found that both delay time and reaction time are reduced by increasing the quantity of component (i). Thereafter, it is found that the effect of an increased amount of component (i) can be tempered by reducing the weight ratio (i):(ii). This invention provides a polyurethane prepared using a catalyst system of the present invention. The following Examples illustrate the invention. In each case the stannoxane used as component (i), prepared by reacting equimolar quantities of the half ester with dibutyl tin dioxide in anhydrous toluene, and the viscometry apparatus, were as disclosed in our OLS 2821306. O Λ, WI - 5 - EXAMPLES 1 TO 15 TABLE 1 1 Propylan D- 1002 3 Bis(ethyl adipatodibutyl tin)oxide 2 Tolylene diisocyanate 4 Triethylamine - 6 - EXAMPLES 16 TO 26 5. Bis(methyl glutaratodibutyl tin) oxide 6. Bis(methyl succinatodibutyl tin) oxide 7. Bis(dodecylsuccinatodibutyl tin) oxide 8. BisOmethyl sebacatodibutyl tin) oxide 9. Bis(ethyl fumaratodibutyl tin) oxide OMPI WIPO - 7 - In the accompanying Drawings several of the Examples (indicated by the reference number at the top of the respective curve) have their kinetic plots shown. Comparative plot 27 was effected with the conventional catalyst dibutyl tin dilaurate under the conditions shown in Table 2.

Claims: -8- CLAIMS 1. A catalyst system comprising: (i) a compound of the formula: OOCQ'COOR. wherein: Q and Q' , which may be the same or different, each represent C to C alkylene, C to C alkenylene or an arylene group; R , R , R and R, , which may be the same or different, each represent a substituted or unsubstituted alkyl group; and x represents zero or an integer less than 6; and (ii) an amine. 2. A catalyst system according to Claim 1 wherein (ii) comprises a tertiary amine of the formula: R 5 R 6 R 7 N wherein: R , R, and R , which may be the same or "different, each, represent a C to C alkyl group. 3. A catalyst system according to Claim 2 wherein (ii) comprises triethylamine. 4. A catalyst system according to any preceding claim wherein R , R , R or R , represents an unsubstituted alkyl group. 5- A catalyst system according to any preceding claim wherein R ■ , R„, R„ or R. represents a C. to C, alkyl group. 2 ^ 1 0 6. A catalyst system according to Claim 5 wherein R. , R , R or R, represents a C to C, alkyl group. 7. A catalyst system according to any preceding claim wherein R. and R are identical. 8. A catalyst system according to Claim 7 wherein R^ and R represent butyl groups. 9. A catalyst system according to any preceding Claim wherein R and R, are identical. 4 10. A catalyst system according to Claim 9 wherein R_ and R, represent methyl or ethyl groups. c <f _ V -9- 11. A catalyst system according to any preceding claim wherein Q and Q' are identical. 12. A catalyst system according to Claim 11 wherein Q and Q' represent a C to C, linear alkylene group. 3• A catalyst system according to any preceding claim wherein x represents an integer less than 4. 14. A catalyst system according to Claim 13 wherein x represents 1 15. A catalyst system according to any preceding claim wherein the weight ratio (i)s(ii) is from 0.8:1 to 1.2:1. 16. A delayed action process for the preparation of a polyurethane, which process comprises introducing a polyol and a polyisocyanate into a reaction vessel in the presence of a delayed action catalyst system according to any preceding claim; forming a homogeneous mixture of the reactants and catalyst system prior to polymerisation! and allowing the homogeneous mixture to polymerise to a polyurethane, 17. A process according to Claim 16 wherein the initial temperature o of the homogeneous mixture is-.below 30 C. 18. A polyurethane prepared using a catalyst system according to any of Claims 1 to 15. 19. A polyurethane according to Claim 18 which is an elastomer/ 20. A polyurethane according to Claim 18 or 19 which is foamed.

Inventors: WILLOUGHBY B
Applicants: NAT RES DEV, WILLOUGHBY B, NATIONAL RES DEV CORP
Application year: 1980
Main classification: C08G18
IPC codes: C08G18, C08G63