CA1262199A - Catalytic copolymerization of bicyclic amide acetals and polyisocyanates - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
An improved process for the copolymerization of a bicyclic amide acetal with a polyisocyanate comprising carrying out the copolymerization reaction in the presence of a catalyst selected from the group con-sisting of tertiary amines, organo tin compounds and iron and nickel salts at a temperature in the range of from about 10°C. to 200°C. is described.

Description

C~3 Thi~ lnvention rel~te6 ~o ~n impxov~D proc~s for . ~ 5 the copolymeriz~tion of bicyclic ~mide ~et~ls and polyi~ yan~e~ and ~ore paxticularly pert~ins ~o a cat~lyt~ pro~es~ iEor the ¢opolymerization of ~icyclic ~mide ~ce~16 ~nà poly~ocyAnates employing organotin and terti~ry a~ine c~t~lyæt~.
The ~eac~ion of bicycl~c amide ~cetals wîth di- or poly-i~ocyan~ge~ ~t higher temperatures to give brittle polymer~ has been de~ribed in Gennan Pa~ent No.
3,235,933. 'rhe use of ~noisture to improve ~he copolymerization oiE bi~yclic ~mide ~ce~a3 ~ ar~d 15 p~lyi~ocyan~tes has been di~cloged in U. S. Patent .
~o. 4, 549, 005 issued October 22, ~9~
I ha~e di o~vered lch~t the rate of ~spolyJnex~zation ~f bieyclic ~Imide ace~al~ ~nd 20 polyisoeyanate~ can be improv~d dr~matically by the use of ~ ~pecified &ati!lly5t in the cop~lymerization pr~cess and tha~ the re~ul~ g polymex~ ve ~uch i~proved phy~ioal propertie~ w~en eompared with the polymers which resul~ ~rom the prior art non-catalyti~ proce~s.
Although b~cyclic a~de ~cetal~ have previou~ly ~een shown to xe~ct w~th ~socy~nates, these reactions generl~lly ~re ~lo~ ~nd require rel~tively high reaction temp~t;~ure~O There ha~ ~een no previou61y described u~e Q~f alny catalyst ln th~ ~opolymerizæ~tion of bicyclic 30 am~de ~cet~l~ with polyi~ocyanate~. I have ~i~covered ~h~ the u6e of ~r~iary amine~ andJor organo~in ¢~aly~ts ~n the copoly~erization of blcyclic ~mide ~cet~ nd polyiE~ocyan~tefi results in ~igo~ ~i.can~ rate $~provement yieldlng polymers oiE ~uch l~pro~cd 35 propert$es ~nd th~lt the proc~s c~n be carried ou~ at relat~vely 1QW t~ r~tures (iExom ab~ut 10C, ~o about ~, t~ "39 200C.~ thus making the process more suitable for many applications such as in the reaction injection molding ~RIM) proce~s.
The bicyclic amide acetals useful in the process of this invention are those conforming to Formulas I, ; lI or III.

7 o R~ R~n Rn R" 2 _ 2 I II III

wher~in R, R' and Rn' independently repres~nt hydrogen, an alkyl group having from l to 15 carbon atoms, an aryl group having from 6 to 12 carbon atoms, an alkyl ether ~roup having from l to 20 carbon atoms or an aryl ether group having from 6 to 20 rarbon atoms; R"
represents an alkyl group having from l to 20 carbon atorns or an alkaryl group having from 7 to 20 carbon atoms; and R~n represents an alkylene group having from 1 to 20 carbon atoms, an alkarylene group having from 7 to 20 car~on atoms, an alkylene ether group having from 1 to 20 carbon atoms or an arylene ether group having from 6 to 20 ~arbon atoms.
The polyisocyanates useful in this inve~tion include organic isocyanates having at least two i~ocyanate groups per molecule. The polyisocyanates can ~e of low~ high or intermediate molecular weight and can be any of a wide variety of organic polyi60cyanate~ including ethylene diisocyanate, ~ 3~

trimethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate trimer, tetraethylene diisocyanate, pentamethylene diisocyanate, propylene-1,2-di-isocyanate, 2,3-dimethyl tetramethylene diisocyanate, 1,4-diisocyanato cyclohexane, cyclopentene-1,3-diisocyanate, p-phenylene diisocyanate, l-methyl phenylene--2,4-diisocyanate, naphthalene-1,4-diisocyanate, toluene diisocyanate, diphenyl-4,-4'diisocyanate, benzene-1,2,4-triisocyanate, xylene-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 ~t least two more fully disclosed in U.S~ Patent Numbers 3,350,362 and 3,382,215. Polyisocyanates which are polymeric in nature including isocyanate prepolymers of all types are included in this invention~
The bicyclic amide acetal group is considered to be at least bifunctional towards the isocyanate group~
The types of catalysts which are most effective in the process of this invention include organo tin compounds such as tin carboxylates, organotin alkoxides and other organotin salt~ (such as organotin thiolates, organotin carboxylate and the like), tertiary amines ~such as Nr ~ Nn-tris [dimethyl amino propyl] hexa hydrotriazine), and iron and nic~el ~alts ~such as iron acetyl acetonate)~ We have found that the inclusion of small amounts of these catalyst~ (0.001 to 5~ by weight based on bicyclic amide acetal) will result in improvements inc.luding ~ignificant polymerization rate increase, lower reaction temperatures required, and much improved 3~. polymer physical properties without the need for postcuring of the polymer. For instance, ~he reaction of a bicyclic amide acetal of Formulas I in which R, R' and R~' are hydrogen and R" is methyl with liquid methylene bis(phenyl isocyanate) at room temperature requires more than 30 minutes to gel and the polymer obtained even after postcuring at 100 degrees C~ for 20 ; minutes has been found to be extremely brittle and no physical properties could be determined because of the brittleness whereas when the same reaction is carried out in the pres nce of ahout 0.05~ by weight of tin ~II) octoate, gelation occurred in less than one minute and the polymer obtair.ed showed notched izod impact strength of 0.4 foot pounds/inch of notch and a heat distortion temperature of about 142 degrees C.
Similarly, when a strong tertiary amine catalyst :L5 (li5-diazabicyclo (5.4.0) undec-5-ene (DBV~) which is partially neutralized with 2-ethyl hexanoic acid or phenolics is used, the gelatiorl occurred within 1.5 minutes and the polymer showed notched izod impact strength of 0.8 foot pounds/inch of notch and a heat distortion temperature of 150 clegrees C. Another interesting improvement which has been observed is that the products of the process of this invention generally have lower specific gravity when compared to the products of the uncataly2ed process of the prior art.
2S Thus~ because of the improvea reaction rate at much lower reaction temperatures and rapid physical properties build up in the product of the process of this invention, the process lends itself to use in the RIM process. Furthermore r the mixture of bicyclic amide acetal and polyisocyana~es which have long open time (at least 30 minutes at room temperature shelf life) and they can be cured rapidly by using catalyst, the system now lends itself for use in applications such as vapor phase cured coatings or vapor injection coatings. Use of other additives known to react with isocyanates such as polyol6, epoxides, oxazolines, x ~

thiols, etc., and inert fillers such as talc, kaoline, glass, carbon, metal powders and the like is within the scope of this invention.

~5 EXAMPLES 1-17 Several experiments were carried out by mixing a variety of bicyclic amide acetals with liquid methylene bis(phe~yl isocyanate) in the absence as well as in the presence of organotin and tertiary amine catalysts.
The reactions were carried out in a 20 ml jar~ The catalyst (when used) was dissolved in the bicyclic amide acetal and the resultin~ mixture was mixed with the polyisocyanate~ The progress of the polymerization reaction was determined by recording the reaction tempera~ure increase of the mixture with time by means of a thermocouple arranqement. The gel time has been considered to be that of the maximum temperature. The reactions, where no or little exotherm was observed, wexe run for a maximum of 30 minutes. The materials used and the results obtained are given in the following Table. It should be noted that Examples 1, 11, 13 and 15 were conducted for purpose of comparison and are outside the scope of this invention.
In the Table A is a bicyclic amide acetal of Formula I in which R, R' and Rn~ are hydrogen and R" is methyl; B is a bicyclic amide acetal of Formula I in which R and R' are hydxogen, R" is ethyl and R~' is C~2OCH~CH=CH2, C is a bicyclic amide acetal of Formula I in which R, R' and R~' are hydrogen and R" is CH2Ph;
D i8 a bicyclic amide acetal o~ Formula II in which R
and R' are hydrogen; R~ is ethyl and Rn~ is C4H8; T-9 is tin (II) octoate; PC SA 102 is 1,5-diazabicyclo (5.4.0) undec-5-ene partially blocked with ethyl hexanoic acid; PC 4:L is N,N'rNn-tris(dimethylamino 3S propyl) hexahydro triazine; DBTDL is dibutyl tin d~laluratet Adogen is tetraalkyl ammonium chloride and ~ 39 Fe(AcAc~ i.s ir~n triacetylacetonate. The polyisocyanate is MDI which is liquid methylene bi~(phenyl isocyanate).

'3~3 TABLE
., 5 Bicyclic Polyiso- Gel Arnide cyanate Catalyst Time Acetal (~) ~ ~ (Min.
A(3.25~ 7.5 None 30

2 A(3.26) 7.4 T-9~0.01) 0.5

3 A13,26) 7.5 PCSA102(0.06) 1.5

4 A13.22) 7.5 PCSA102~0.09) 1.0 A(3.27) 7.5 PC41(0.05) 3.5 6 A~3.22~ 7.6 DBTDL(0.011 1.2 7 A(3.23) 7,5 DBTDL(0.01) 0.7 PC41 ~0.05) 8 A(3.25) 7.4 ADOGEN (0.1) 10 9 A¦3.2) 7.4 Fe~ACAC) (0.05) T-~ (0 . 01) 0. 5 A(3.27) 7.6 T-9(0.01) 0O8 PC41 ~0. 05) 11 B l5. 3) 7. 6 None 30 12 B(5.31 7.6 T-9(0.01) 1.5 13 C(5.1) 7. 6 None 30 14 C (5. 1~ 7. 6 ~-9 ~0. 1) 1 . 0 A (3. 2) g. 2 ~one 30 ~1.0) 16 A (3. 2~ 9. 2 T-9 (O. 01) 0. 7 17 A(3.2) 9.2 DBTDL(0.01) 1.0 D(1.0) ~. ~ t;~" ~ 9 9 This experiment which was carried out in the absence of any catalyst is for comparative purposes and is outside the ~cope of ~he present invention. The ~5 methyl substituted bicycl~c amide acetal of Formula I
in which R, R', and Rn' are hydrogen and R~ is methyl (32.5g) was degassed on a rotary evaporator under reduced pressure and was mixed with 78g of degassed liquid methylene bis(phenyl isscyanate). The resulting mixture was poured into a mold prepared from two parallel silicone coated glass plates held apart by l/8 inch spacers. The mold was placed in an oven at 100 degrees C. for 20 minutes. The polymer sheet obtained in this manner was found to be extremely brittle so that no physical testing could be done on it. The specific gravi~y for this polymer was found to be 1~286.

The procedure of Example 18 was followed usin~ the same reaction charge~ The bicyclic amide acetal ~32.5g) was mixed with 0.07g of stannous octoate catalyst and the degassed mixture was mixed rapidly with 78g of liquid MDI was poured into the mold. The polymer was cured in 20 minutPs a~ lO0 degrees C. and was found to have a notched izod impact strength (~S~M
D-256) of 0.4 foot pounds/inch of notch, an unnotched izod impact strength of 2.5 foot pounds~inch, a heat distortion temperature (ASTM D-648) of 142 degrees C., a flexural ~trength ~ASTM D-790~ of 20,947 psi and a flexural modul~s of.~40,855 psi. Th~ specific gravity of the polymer was :I d 279 ~

The proce~ure ~f:Exampl~ 18 was followed using 33g of bicyclic amide acetal, O.lg of Polycat SA lO~ and $

~ 3~3 79g of liquid MDI. The polymer was found to have a notched izod impact strength of 0~8 foot pounds/inch of notch~ dn un~otched izod impact strength of 14 foot pounds3inch and a heat distortion tempera~ure of 149 '5 degrees C. The polymer was also found to have a specifi.c gravity of 1.270.

This is a comparative example outside the scope of the present invention. The reac~ion mixture of Example 18 was poured into the heated mold ~60 degrees C.) and was left under open atmospheric temperature for 20 minutes. The polymer formed was extrPmely brittle and no physical properties could be determined.
EXAMPLE 2~
The procedure of Example 21 was followed using 34.39 of the bicyclic amide acetal of Formula 1 in which Rn is methyl and R, R' and Rn' are hydrogen, 0.04g of stannous oc~oate catalyst and 85g of liquid MDI. A rapid polymerization occurred within 30 seconds of the time the mixture was poured into the mold. The resulting polymer was found to have a notched izod impact strength of 0.3 foot pounds/inch of notch, a heat distortion temperature of 140 degrees C., a flexural strength of 12,056 psi and a flexural modulu~
of 439,b66 psi.

E~YAMPLE 23 The procedure of Example 21 was followed using 34.2g of the bicyclic amide acetal, 0.12g of Polycat SA
102 And 83.3g of liqui~ MDI 'nhe polymer was found to have a notched izod iml ~ct s..engtil of 0.8 foot pounds/inch of notlch, ~ unn, ched izod impact streng~h of 7 foot pounds/inch, ; hea~. ~istortion temperature of 3~3 148 degrees C. a flexural strength of 25,126 psi and a flexural modulus vf 391,084 psi.

'5 An isocyanate prepolymer was prepared by reacting 90g of liquid MDI, lOg of liquid diglycidyl ether of Bisphenol-A lepoxy equîvalent weigh~ of 185) and lOg of carboxylic acid group terminated acrylonitrile-butadiene copolymer (molecular weight of 5000 containing 18~ acrylonitrile) at 90-100 degrees C. for three hours. The procedure of Example 18 was followed using 34g of the bicyclic amide acetal, OOlg of dibutyl tin dilaurate catalyst and 86g of the above isocyanate prepolymer. The polymer was cured for 43 minutes at 100 degrees C. and was found to have a notched izod impact strength of 0.85 foot pounds/inch of notch, an unnotched izod impact strength of 8.5 foot pounds~inch, a heat distortion temperature of 118 degrees C., a flexural strength of 19,827 psi and a flexural modulus of 424,71B psi.

~XAMPLE 25 The procedure of Example 18 was followed using 34g of the bicyclic amide acetalJ O.lg of N,N',Nn-tris-~dimethyl amino propyl~ hexahydro triazine, 0.04g of dibutylin dilaurate and 80g of liquid MDI. The resulting polymar was found to have a notched izod impact strength of 0.3 ft. lb~in of notch, Flexural strength of 14,828 p~i and a flexural modulus o~
583,559 psi.

Claims (17)

I CLAIM:

1. An improved process comprising copolymerizing a bicyclic amide acetal with a polyisocyanate at a temperature in the range of from about 10°C. to about 200°C. in the presence of a catalytic amount of at least one member selected from the group consisting of tertiary amines, organo tin compounds and iron and nickel salts.

2. The process of Claim 1 wherein the bicyclic amide acetal is one having the formula I, II or III

I II III
Wherein R, R' and R" independently represent hydrogen, an alkyl grounp having from 1 to 15 carbon atoms, an aryl group having from 6 to 12 carbon atoms, an alkyl ether group having from 1 to 20 carbon atoms or an aryl ether group having from 6 to 20 carbon atoms; R" represents an alkyl group having from 1 to 20 carbon atoms or an alkaryl group having from 7 to 20 carbon atoms;
and R'''' represents an alkylene group having from 1 to 20 carbon atoms, an alkylene group having from 7 to 20 carbon atoms, an alkylene ether group having from 6 to 20 carbon atoms.

3. The process of Claim 2 wherein the catalyst is present in from 0.001 to 5% by weight based on the weight of the bicyclic amide acetal.

4. The process of Claim 3 wherein the tertiary amine is N,N',N"-tris(dimethyl amino propyl) hexahydro-triazine, the organo tin compound is a tin carboxylate, an organo tin alkoxide or an organotin thiolate and the iron salt is iron acetyl acetonate.

5. The process of Claim 3 wherein the polyisocyanate is one having at least two isocyanate groups per molecule.

6. The process of Claim 5 wherein the bicyclic amide acetal is one of Formula I in which R,R' and R''' are hydrogen and R" is methyl.

7. The process of Claim 5 wherein the bicyclic amide acetal is one of Formula I in which R and R' are hydrogen, R" is ethyl and R''' is CH2OCH2CH2CH=CH2.

8. The process of Claim 5 wherein the bicyclic amide acetal is one of Formula I in which R, R' and R''' are hydrogen and R" is CH2Ph.

9. The process of Claim 5 wherein the bicyclic amide acetal is one of Formula II in which R and R' are hydrogen, R" is ethyl and R'''' is C4H8.

10. The process of Claim 5 wherein the catalyst is tin (II) octoate.

11. The process of Claim 5 wherein the catalyst is N,N',N"-tris-(dimethyl amino propyl) hexahydro triazine.

12. The process of Claim 5 wherein the catalyst is dibutyl tin dilaurate.

13. The process of Claim 5 wherein the catalyst is tetraalkyl ammonium chloride.

14. The process of Claim 5 wherein the catalyst is iron acetyl acetonate.

15. The process of Claim 5 wherein the polyisocyanate is methylene bis(phenyl isocyanate).

16. The process of Claim 6 wherein the catalyst is stannous octoate and the polyisocyanate is methylene bis(phenyl isocyanate).

17. The process of Claim 6 wherein the catalyst is dibutyl tin dilaurate and the polyisocyanate is an isocyanate prepolymer.