Chemical synthesis of hydroxy terminated perfluoro ethers as intermediates for highly fluorinated polyurethane resin

Rochow, S. E.

Stump, E. C., Jr.

English

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~lizabeth A; ~ a r / t e r  
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3 f.243 (CATEGORY) 
https://ntrs.nasa.gov/search.jsp?R=19710017778 2020-03-17T03:12:54+00:00Z
3,574,7 70 Utlited States Patent Ofice Apn. 3, 197P 
(3) Objects of the i a v ~ t i o n  
3,574,770 
TED PERFLUOR0 EmERS An object of this invention is lo pnovrdc navel bydloxyl 
T. 0. paine, ~~6~~ t&dmi~shlator of the ~ ~ f i ~ ~ ~ l  A ~ ~ ~ -  terminated prfluoroethers useful as hntrinledia:cz rn 
laau6es anit Space Administrafion, with respect $0 am forming new polymers. 
invena&on of Eugene C. $&nap, Jr., and Stephen Engene 5 Another object of this inve~tion is to provide new 
Woehow, GdnesviBBe, FBa. highly fluorinated polyurethane resins. 
No Drawing. Rled QPet 24, $968, Ser. No. 770,398 
Int. el. @We 43/00 SUMMARY OF THE HNVENTIOI4 
U.S. el. 260-615 2 Claims The herein invention involves the initiai formarlan of 
10 highly fluorinated diofs containinn ether 1;nbaees and 
Hydroxy terminated perfluoro ethers and polyurethane 
resins incorporating the structure 
-CH2CF (CF,) iOCF2CF (CF3) ImO (CF2,)pQ 
LCF (CF3) CF201 ,CF(CF,) CH- 
where 
p is an integer of 2 to 12, and 
m and n are integers whose sum is from 0 to 20. 
having the general formula 
- - 
HOCH&F(CF3) [OCF2@F(CF3) lmO (;CFa)DO 
lCF(CQ3)CFZOlnCF(CF3)CEZ8R 
These materials are prepared by reducing tine acid jilroi~de 
terminated precursors formed in accord with the descrip- 
tion in the aforegoing mentioned Pat. 3,25@,087, by rent- 
lion with a reducing agent such as li:b:ucq aBumrnum hy- 
dride or an alkali metal borohydrid-. The bj~droxjil tcr- 
minated ethers are useful as in:emecii:rtas in tne pr-pnva- 
tion of various materials and particular31 ~n ~ h c  ffir~:a- 
tion of polymers. They have been rrvli~ecl to losrr-rtiatc 
O H G I N  O F  THE INVENTION new ananovel polyurethanes by reactilg ~hese dioIs with 
a suitable diisocyanate. Of particular impoi'ance ;Q the The invention described herein was made in the per- 25 formation of highly fluorinated polyurethanes where: "ie 
formance of work under a NASA and is subject dials of this invention are reacted ~iitl? th",highly fiori- 
to the provisions of section 305 of the National Aero- nated diisocyanates such as tetral"uoro-m-pIICnj~kene diiso- 
nautics and Space Act of 1958, Public Law 85-568 (72 cy,ate- Stat. 435 U.S.C. 2457). 
BACKGROUND OF THE INVENTION 30 DESCRIPTION OF THE P R E F E R R J ? ~  EMBODIMENT3 
(1 ) Field of the invention 
As indicated, the preparation of [he zc-6 flrrolide ler- 
This invention is in the field of new perfluorinated ether 
,inated precursors of the herein in-cier~tion is &orou~hly 
materials, more particularly the invention relates to a new described in Pat. 3,250,807. Basical]y, the ;leaterials are 
hydrox~ terminated pepfiuoroether and a ~ o l ~ u r e t h a n e  35 prepared by the reaction of &acid finorides with hrxafluo- 
resin derived from that ether. ropropylene epoxide in the presence of a surtable catalyst 
(2) Description of the prior art such as cesium fluoride. The precursors are one of a fr-LC- 
tion of the products obtained from Ihat reaction. A spe- Highly fluorinated polymers are of particular interest 
cific example fohming the precwsoi jnvol\ es ibe reac- 
because tend possess outstanding resist- *' tion of hexafluorapropy~ene oxide with gerflrroroglu~avyl 
with good properties and nOn-flammabilit~. fluoride in fie presence of cesium flLioride a sn:;ai31e 
These properties are attributable mainly to the presence of 
solvent. the fluorine atoms in the polymer chain. As a result, poly- The precursor acid fluoride terminated ethers are cen- that are perRuorinated Possess the maximum 45 verted to diois in wi& the herein illvention by foregoing properties. reduction through the use of a maten21 such as an alkali There is disclosed in U.S. Pat. 3,250,807 the diacid 
metal borohydride or an alumiwLlm hydri2e, Reducuon fluoride precursors of the herein invention having the takes place in presence of an inelt sorvcrle sue? general formula dioxane or diethyleneglycol dimet".r:rl ether. --he diacid 
0 0 50 fluoride starting material is usually ad!!-d d:oswise to 
F~CF(CF~)[OCF~CF(CP~)~~O(CF~),O[CP(CF~)CF~~].CF(GF~)~~ the solution of the solvent and reducing agent m:xfnrc. 
The temperature at  which the reducf~on 1.; carried out 
where is not critical. Normally the reactants are hcated to a 
p=integer of 2 to 12, temperature not in excess of the boiling temperature of 
m+n=integers of 0 to 20. 55 the solvent. UsualPy the reactants are s:irrcd daring the: 
reaction for a period of up to three I~ours. i i W e  r:ki 
That patent disclosed utilization for these ethers as chern- of this time, is preferably acidcd to remove 2inv ical intermediates. As indicated therein, the materials excess borohydride present. n i s  is dIen followled by 
would have outstanding thermal and chemical properties separation of the desired end product. 
when utilized as dispersing agents and the like. Further, The diol products produced from the a2aregolng de- 
the patent indicated that due to the particular end group " scr ibe~ reductmn can be ahen utilized to form poiy- 
structure, i.e., urethanes by reacting them with suitable d~i~ocyznales, 
0 Any diisocyanate conventionally utilrzed to arodrlce pc'y- 
-8 F urethane resins is contemplated. This inc\iidcs folrmeno di- 
65 isocyanate including mixtures of its mxazrs sjzh as th- 
the materials could be decarboxylated, to result in vinyl 2,4 and 2 , j  isomers. Further conlcmplat& i s  dipi.ce?yi- 
ethers which would have utility as mOnOnlerS in the for- methane-4,4'-diisocyanate, Barliculal 5, it desirable jq 
malion of thermosetting resins. There was no appreciation the herein invention to utilize d i i ~ ; c ~ ~ ~ ~ s a i ~  *,o obidm 3 
of the conversion of the carboxyl grouping to a hydroxyl maximum amount of fluoride atoms. The extremely good 
one and the subsequent utilization of the hydroxy ter- high temperature properties, nonilam nabrIity rind the hki: 
minated material in the formation of novel polyurethane can be attributed to the presence cbf fluor-ne atoals 51 
resins. the polymer chains. Thus, if the diisc!cymate also con- 
rains a high substitution of fluorine atoms, one obtains 55" C.  The mixture was then heated at  75' C. for six 
a golymel- containkg the desired properties. Thus, it is hours, to  assure complete hydrolysis of unreacted hy- 
pae'erred to use d~lsocyanales such as tetrafiuoro-2,4- dride. 100 milliliters of additional water was added and 
phe3yleee diisocyanate, tetrafluoro-p-phenylene diisocy- the mixture then allowed to cool. The lower layer was 
anate, pe-fluorotrhethylene diisocyanate, 1-chloro-2,4- separated and the upper layer was extracted three times 
di1socyan~to-3,4,6-t1ifluorobenzene and the like. with ether. This material was combined, the ether was 
The resultant polymers will range from sticky semi- stripped and the remainder distilled to  give 69 grams 
solids to tough baitile sheets depending upon the amount of 
o i  diisocyanate utilized in the extension and cross-link- 
ing reaction that transpires between it and the diols. It HOCH&E (CF3)OCE2CF (CF3) 0 
should be noted that although the hardness of the re- (C&) 50CF(CF3CH20H 
snitant pezlyrslers increases with the increasing ratio of EXAMPLE IrtT 
d~nsocyar,zte to did ,  the glass temperature of the re- The procedure set forth in Example 111 was repeated, 
sniltant polyhlreiha~~es is not aversely affected. n u s ,  it is utilizing 4 grams or -106 mole of sodium borohydride, 
coatemplated to utilize a mole ratio of diisocyanate to 15 and 45 grams of .05 mole of a diacid fluoride having 
diol of from 1:4 up to 3: 1. The preferred mole ratio the formula 
range of tiie diisocyanate to diol is from 1:l to 2: 1. 
The time and temperature of the polymerization re- 0 0 
action is dependent rlpon the molecular weight of the pre- /I FCCF(CP,)[OCFICF(CPJ)J,O(CB(CF~)CF~~],CF(CF~)~F 
pc l~mef  and the type of diisocyanate used. Completion 20 where m+n=2, together with 75 grams of dioxane. 
of poiymerization lor the given di0l-diisocyanate can be The material was dried with magnesium sulfate prior to 
determined by the iilcrease in viscosity of the melt ~ 0 1 ~ -  distillation. This produced 32 grams of the dial having 
mer. Generally the temperature of curing can vary from the formula 
25" t~ laSOo,  while the time of the cure can range from 
80 to 30 minutes. Id. is believed that the invention will 2j HcXH2CE(CF3)[QCF2CE(C~)lmo(CF2)50 
be further sulderstuod from the following detailed exam- [CF(CF,) CF2B] ,CF(CF3) CH20N 
where m+n=2. 
EXAMPLE V 
One pound of dry ethyl ether was added to a 2-liter, The procedure of Example I11 was repeated, utilizing ?-necked flask thai bad been flamed out under nitrogen. 30 grams or .079 mole of sodium borohydride and 40 
 he flask was eqeripped with a condenser, stirrer and gpams or .0137 mole of a diacid fluoride having the formula 
addition funnel, To the ethyl ether was added 13.5 grams 
or .35 mote of lffhi\irn aluminurn hydride. 100 grams or 0 
"244 a d e  of P ~CF(CF~)[OCF~CF(CF~)J,O(CFI)~O[CF(CFJ)CP~~~.CF(CF~&F 
a 0 35 where m+n=3, and 55 grams of dioxane in a 200-IILilli- 
1 I /I 
F C(CF?) IOCB(CF~)CF  liter 3-necked flask. Distillation gave 17 grams of the diol 
was added dropwise to maintain reflux. The mixture was having the formula 
heated at s e e m  15 minutes after the addition was com- HOCR2CF(CE,) [OCF2CF(CF3)]mO(CF2)50 
plctc. Upon cooling, 15 milliliters of water was added 40 [CF(CjF3) (CF201nCH(CE3)CHzOH 
slowly over one horir, and the whole mixture was added 
ao 600 mi11ililers of 6 N to assure conlplete hy- wherem+n=3' 
drolvsis of the nnreacted hvdride. The ether laver was EXAMPLE M 
used to extract the water, -and the ether solution was In this example a polyurethane was utilizing distilled giving 69 grams of 45 8.75 grams or .01 mole of the diol product of Example 
HOCH2(CF2)40CF(CF3)CW20H IV, and 2.32 grams or .O1 mo!e of tetrafluoro-m-phenyl- 
Identiiicd sy  infrared, NMR, and elemental analysis. ene diisocyanate. The reactants were mixed and-heated 
for 90 minutes at 165" C. and an additional 30 minutes 
EXAMPLE II at 185" C. under vacuum to prevent nloisture from en- 
Utilizing the procedure of Example I, 102 grams or tering the system and reacting with diisocyanate. The ma- 
"177 mole of terials were then press cured at 160" C. for 30 minutes 
0 0 at 1000 p.s.i. to produce a sticky, elastomeric, semisolid 
' I  I/ film. 
T C L F ( C F ~ ) ~ ( C F ~ ) ~ O C P ( C F J ) C F  
55 EXAMPLE WI 
was reduced with 9 grams or .237 mole of lithium alumi- 
num hydride. The ether residue was heated at  reflux Example VI was repeated, however, a ratio of diiso- 
with benzcne, using a Dean-Stark apparatus to remove cyanate to diol of 1.4 to 1 mole produced a hard, clear 
watcr. Distillation gave 63 grams of film having a glass transition temperature of -53" C. and 
NOCH2CFI(@l'3) 0(CF2)50CF(CF3)CH20H 60 a Shore A hardness of 73. 
identified by inhared, NMR, and elemental analysis. EXAMPLE VIII 
ErnWIPLE I H  9.75 grams or .0094 mole of the diol produced in Ex- 
1/10 grams of dry dioxane was added to a 500-milli- ample V was mixed with 4.34 grams or .0187 mole of 
liter 3-necked flask with a stirrer, condenser, addition 65 tetrafluoro-m-phenylene diisocyanate. The reactants were 
fznmei and thermometer. 6.8 grams or .18 mole of sodium heated for 120 minutes at  162" 6. forming a thick fluid. 
hoiohydride was added. This was followed by a dropwise This fluid was then placed in a mold for 30 minutes at 
addition of 400 grains or ,135 mole of 160" C. and pressed at 2000 p.s.i. This produced a clear, 
o o hard sheet having a glass transition temperature of -58" 
1 1  I1 70 C. and a Shore A hardness of 97. 
F CCF(CFi) ~ C F ~ C F ( C F ~ ) O ( C F ? ) G O C F ( C F J )  C F  
with stirring at 28" to 75" C. over 3 hours. The mixture EXAMPLE IX 
was headed at 50-75' C. with stirring for an additional 
3 hours and cooled. 100 milliliters of water was added The tetrafluoro-m-phenylene diisocyanate utilized in 
sbwly over one hour, keeping the temperature below 75 the above examples was prepared by reacting tetrafluoro- 
3,574,770 
5 
m-phenylene diamine with chlorocarbonyl pyridinium where 
6 
chloride. 1300 milliliters of dry diethyl ether was placed is an integer of to 12, and in a 3-liter, 5-necked flask equipped with stirrer, ther- 
mometer, gas bubbler, two addition funnels and a low tem- rn and n are integers whose sum is from 0 to 20. 
perature condenser. 173 grams of phosgene was added at 2. The diol of claim 1 where p is 5 
-50" C. To  the phosgene was added 120 grams of pyri- 
dine and 250 milliliters of ether slowly at -50" C., form- References Cited 
ing a yellow solid. After addition, the mixture was stirred UNITED STATES PATENTS 
30 minutes at  -40" C .  Following this, 50 grams of tetra- 
fluoro-m-phenylene diamine was dissolved in 400 millili- 3,250,807 5/1966 Fritz et al. -- -- 260-615BFWX 10 3,402,169 9/1968 Jackson ----__-_-- 260-615BF ters of ether and added as the flask was allowed to warm 3,452,103 6/ 1969 Trischler --------- 260-6 5BF 
with stirring to room temDerature. The mixture was then 
stirred twokours at  10" ^ to 20" C. The solids were re- FOREIGN PATENTS 
moved by filtration and the solvent removed under vacu- 528,136 7/1956 Canada --------- 260-615BF 
um leaving a light yellow liquid. Distillation gave 37 15 
grams of clear tetrafluoro-m-phenylene diisocyanate. HOWARD T. MARS, Primary Examiner 
What is claimed is: 
U.S. CI. X.R. 
1. HO-CH2CF(CF3) [OCF2CF(CF3) 1,O 260-2, 77.5 
(CF2)pO[GF(CF3CF201nCF(CF,)CH~-OH 20 


Hydroxy terminated perfluoro ethers Patent

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