Perfluoroalkyl polyether glycols and their use

Homo- and copolymers of 3-perfluoroalkyl-1,2-epoxypropane having a number average molecular weight between about 650 and 5000, preferably 1000 to 3000, are prepared by polymerizing 3-perfluoroalkyl-1,2-epoxypropane in the presence of an acidic catalyst and preferably a molecular weight controlling agent.

FIELD OF THE INVENTION 
The present invention relates to polyether glycols containing pendant 
perfluoroalkyl groups, and to segmented block copolymers derived 
therefrom. 
BACKGROUND OF THE INVENTION 
Polyether, polyester or polycarbonate glycols at molecular weights of 650 
to 5000 are usually used as soft segments in various segmented block 
copolymers such as polyurethanes and elastomeric polyesters. On the other 
hand, compounds which contain perfluoroalkyl groups of sufficient length 
are known to dramatically reduce surface energy in systems, giving rise to 
water and oil repellency as well as antisoiling properties. 
Fluorine-containing polyethers of the formula: 
##STR1## 
are disclosed in U.S. Pat. No. 3,242,218, and polyether glycols of the 
formula: 
##STR2## 
are disclosed in U.K. Patent Specification No. 782.615. The former 
materials are nonfunctional compounds; consequently, they could not be 
used to form segmented block copolymers. On the other hand, the latter, 
due to the single perfluoromethyl group, provides such very marginal 
surface energy reduction that it is incapable of providing any effective 
oil or water repellency. U.S. Pat. Nos. 3,896,251, 4,046,944 and 4,540,765 
disclose the preparation of polyurethanes, using glycols of the gene al 
formula: 
##STR3## 
However, it is well known that monomeric glycols such as those disclosed 
in the latter three U.S. patents yield segmented polymers having inferior 
physical properties, such as tensile strength and modulus; e.g. they fail 
to give polyurethanes having sufficient elasticity. Monomeric glycols or 
diamines are usually used as curing agents or chain extenders and become 
part of the hard segment. On the other hand, the amorphous soft segment in 
form of an oligomeric ester, ether or carbonate glycol has to be long 
enough to equalize the hard crystalline urea or urethane segment. 
U.S. Pat. No. 4,427,803 discloses using polyethers derived from 
3-perfluoroalkyl-1,2-epoxy-propane in combination with other materials as 
mold release agents. The patentees state that their polymers are known 
from British Patent No. 782615 which discloses cationic polymerization of 
3,3,3-trifluoro-1,2-epoxypropane or its 2-methyl analog to a high 
molecular weight polymer; e.g. the former is polymerized to a molecular 
weight in excess of 50,000. Using the British process with the monomers 
disclosed in the U.S. patent leads to nonfunctional cyclic ethers and/or 
high molecular ethers with a functionality of less than two. Because such 
products have little or no functionality, they apparently are well suited 
as mold release agents. By the same token, however, they are quite 
unsuitable for making useful polymers. European Patent Application 0 152 
065 prepares copolymers of .OMEGA.-perfluoroalkyl-1,2-epoxyalkanes 
(including propane) with various other epoxy compounds. No chain transfer 
agent is recited in the Examples of the European Application, and as a 
consequence, the copolymers are of high molecular weight, making them 
unsuitable for incorporation into segmented block copolymers, such as 
polyurethanes and elastomeric polyesters (the average molecular weights 
are between 7050 in Example 3 and 13,600 in Example 12). In a similar 
fashion, water-and oil-repellent agents are described in Japanese Patent 
Application 46-25361, published July 22, 1971. Those agents comprise 
homopolymers and copolymers prepared by polymerizing 
3-perfluoroalkyl-1,2-epoxy-propanes in the absence of any molecular weight 
control agent. As a consequence, those polymers also would be unsuitable 
for preparing the above-mentioned segmented block copolymers, as their 
molecular weights would be entirely too high. 
BRIEF SUMMARY OF THE INVENTION 
Novel polymers of 3-perfluoroalkyl-1,2-epoxy-propane having a number 
average molecular weight in the range between about 650 and about 5000 are 
provided. They can be prepared by polymerizing 
3-perfluoroalkyl-1,2-epoxypropane in the presence of an acidic catalyst 
and a molecular weight controlling agent.

DETAILED DESCRIPTION OF THE INVENTION 
The novel polymers of the present invention comprise oligomeric glycols 
having a molecular weight in the range between about 650 and about 5000, 
preferably between about 1000 and about 3000, most preferably about 1500 
to about 2000, which can be represented by the general formula: 
##STR4## 
wherein R is a divalent radical of the formula: 
##STR5## 
R.sup.1 is a divalent aliphatic hydrocarbon radical containing 2 to 12 
carbon atoms; 
R.sub.f is a straight or branched chain perfluoroalkyl radical containing 4 
to 12 carbon atoms or mixtures thereof; 
x is 0 to 10; 
y is 0 to 10; 
n is 2 to 10, and 
z is 0 or 1. 
Tetrahydrofuran can serve both as a solvent and as a comonomer for the 
purposes of this invention; in that case, x is 1 to 20. 
The fluorinated monomers most preferred for the purposes of the present 
invention are those wherein R.sub.f is a mixture of perfluoroalkyl groups, 
CF.sub.3 CF.sub.2 (CF.sub.2).sub.m in which m is 2, 4, 6, 8 and 10 in the 
approximate weight ratio of 0.3/61.4/31.8/6/0.3. 
The oligomeric polymers of this invention 
comprise copolymers as well as homopolymers. The oligomeric copolymers and 
homopolymers of this invention can be prepared in the presence of an 
acidic catalyst. Copolymers can be prepared in accordance with this 
invention from 3-perfluoroalkyl-1,2-epoxypropane and one or more 
comonomers, such as ethylene oxide, 1,2-propylene oxide, epichlorohydrin, 
oxetane, tetrahydrofuran, and the like. The acid catalyst can be 
fluosulfonic acid; a Lewis acid such as antimony pentafluoride, boron 
trifluoride, tin tetrachloride, aluminum trichloride, etc.; solid acidic 
materials such as acidic montmorillonite clay or a strongly acidic 
cationic resin commercially available from E. I. du Pont de Nemours and 
Company as NAFION.RTM. perfluorosulfonic acid resin. 
Except when fluosulfonic acid is used as a catalyst, a chain stopper (a 
molecular weight control agent) should be used. Otherwise, the product 
will be too high in molecular weight to serve as soft segments in 
segmented block copolymers, such as polyurethanes and elastomeric 
polyesters. When fluosulfonic acid is used as the catalyst, the molecular 
weight of the product can be controlled by controlling the amount of 
catalyst used. The molecular weight of the polyether glycol oligomers of 
this invention will largely depend upon the amount of molecular weight 
control agent used. Generally water or any glycol containing from 2 to 
about 12 carbon atoms, and more desirably from 2 to 6 carbon atoms, may be 
utilized. Example of specific glycols include ethylene and the various 
propylene, butylene and hexylene glycols. By the term "various" the 
various isomers of the glycol are meant. Preferred compounds include 
ethylene glycol, 1.4-butanediol and 1,6-hexanediol. Generally a range from 
about 0.05 to 0.5 mole of diol or water per mole of monomer is used. If 
solid acidic catalysts are used (acidic montmorillonite, NAFION.RTM. H+ 
resin or the like) the preferred molecular weight controlling agent is 
acetic anhydride. The desired polyether glycol is then liberated by 
saponification of the corresponding diacetate. When a glycol is used as 
the molecular weight controlling agent, "z" in the foregoing formula is 1 
and "-OR.sup.1 -" is a radical derived from the glycol. When water or an 
anhydride is used for that purpose and the resulting diacetate hydrolyzed, 
"z" is 0. 
Before the polyether glycol is converted into a polyurethane or polyester, 
catalyst residues, excess diol, water and monomers are removed. The 
fluorine-containing polyether glycol of this invention can be used as soft 
segment by itself or in combination with other commercially available 
polyether glycols, polyester glycols or polycarbonate glycols. The 
preparation of polyurethanes or polyesters can be carried out in bulk or 
in a suitable solvent. Aqueous polyurethanes can be made if appropriate 
ionic modifiers are used. For the preparation of a polyurethane, any 
aliphatic or aromatic di- or poly-isocyanate can be used, usually in 
excess so that the polyurethane chains or networks that are formed carry 
at their ends free isocyanate groups which can either be extended to their 
optimum length with short chain aliphatic or aromatic glycols as well as 
diamines, or be blocked with a suitable protective group. For the 
preparation of linear polyesters any aliphatic or aromatic diacid or 
anhydride can be used together with short chain aliphatic or aromatic 
glycols. 
The following examples are illustrative of the invention. The 
3-perfluoroalkyl-1,2-proplyene oxides used in the examples are the most 
preferred such compounds described hereinabove. Unless specified 
otherwise, the composition of the products described in the examples was 
determined by proton NMR. 
EXAMPLE 1 
Into a reactor was charged 1 mol of 3-perfluoroalkyl-1,2-propylene oxide 
with an epoxide equivalent of 487 and 0.27 mole of ethylene glycol. To the 
mixed components was added at 5.degree. C. under nitrogen 5.4 ml of a 
boron trifluoride/tetrahydrofuran complex at a rate of 0.15 ml per minute. 
The resulting exotherm (to 126.degree. C.) was controlled by cooling with 
an ice-bath to a temperature of about 50.degree. C. The reactants became 
homogeneous and viscous, and the agitated reaction mass was then held for 
2 hours at 75.degree. C. before the addition of 60 ml of deionized water. 
After holding with agitation for 1 hour at 75.degree. C., 8.8 g of calcium 
oxide powder was added and heating was continued with agitation for 
another hour at 75.degree. C. The reaction product was then filtered and 
dried for about 2 hours at 80.degree.-85.degree. C. under a pressure of 
1300-2000 Pa (10-15 mm Hg), giving rise to a straw-colored viscous oil, 
which partially crystallized on standing. The polyether glycol thus 
obtained had the following characteristics: 
(1) Number average molecular weight: 1533 
(2) Viscosity: 2.9 Pa.s at 40.degree. C. 
(3) Fluorine Content: 67.0 Wt % 
(4) Composition: 
______________________________________ 
By Weight 97.7% of 3-perfluoroalkyl-1,2-propylene 
oxide 
2.3% of ethylene glycol 
Mole Ratio 3-perfluoroalkyl-1,2-propylene oxide/ 
ethylene glycol = 1:0.265 
______________________________________ 
EXAMPLE 2 
Into a reactor was charged with agitation 1 mol of 
3-perfluoroalkyl-1,2-propylene oxide with an epoxide equivalent of 440, 
2.65 moles of tetrahydrofuran and 0.269 mole of ethylene glycol. The 
agitated monomer mixture was cooled under nitrogen to 4.degree. C. before 
the addition of 5.1 ml of boron trifluoride/-tetrahydrofuran complex at a 
rate of 0.15 ml per minute. The resulting exotherm to 43.degree. C. was 
controlled through intermittent cooling with an ice-bath to a temperature 
of about 20.degree. C. After completion of catalyst addition, heating with 
agitation was continued for another hour at 70.degree. C. To the agitated 
homogeneous reaction mass was added 180 ml of deionized water. After 
holding with agitation for 1 hour at 70.degree. C., 9 g calcium oxide 
powder was added and heating was continued for another hour at 70.degree. 
C. The reaction product was then filtered and dried for about 2 hours at 
80.degree.-85.degree. C. under a pressure of 1300-2000 Pa (10-15 mm Hg), 
giving rise to a straw-colored viscous oil. 
The copolyether glycol thus obtained, had the following characteristics: 
(1) Number average molecular weight: 1696 
(2) Viscosity: 2.5 Pa.s at 40.degree. C. 
(3) Fluorine Content: 48.6 Wt % 
(4) Composition: 
______________________________________ 
By Weight 75.2% of 3-perfluoroalkyl-1,2-propylene 
oxide 
22.8% of tetrahydrofuran 
2.0% of ethylene glycol 
Mole Ratio Tetrahydrofuran/3-perfluoroalkyl- 
1,2-propylene oxide/ethylene glycol = 
1:0.54:0.14 
______________________________________ 
EXAMPLE 3 
In an appropriate container, a homogeneous monomer feed was made up 
consisting of 1 mol 3-perfluoroalkyl-1,2-propylene oxide (epoxide 
equivalent 440), 2.65 mols of tetrahydrofuran and 0.269 mol of ethylene 
glycol. With agitation, 75 ml of the homogeneous monomer feed was charged 
into a reactor. The agitated monomer feed was cooled to 3.degree. C. under 
nitrogen before the addition of 5.1 ml of boron 
trifluoride/tetrahydrofuran complex at a rate of 0.15 ml per minute. 
During addition, the temperature rose slowly to 37.degree. C. After 
completion of catalyst addition, the remaining monomer feed was added with 
agitation at such a rate as to maintain the reaction temperature between 
36.degree. and 42.degree. C. The agitated reaction mass was then held at 
50.degree. C. for 3 hours before the addition of 120 ml of deionized 
water. After holding with agitation for 1 hour at 50.degree. C., 9 g of 
calcium oxide powder were added and heating agitation were continued for 
another hour at 50.degree. C. The reaction product was then filtered and 
dried for about 2 hours at 80.degree.-85.degree. C. under a pressure of 
1300-2000 Pa (10-15 mm Hg), yielding a straw-colored viscous oil. The 
copolyether glycol thus obtained had the following characteristics: 
(1) Number average molecular weight: 1710 
(2) Viscosity: 2.6 Pa.s at 40.degree. C. 
(3) Fluorine Content: 51.1 Wt % 
(4) Composition: 
______________________________________ 
By Weight 76.5% 3-perfluoroalkyl-1,2-propylene oxide 
21.6% tetrahydrofuran 
1.9% ethylene glycol 
Mole Ratio Tetrahydrofuran/3-perfluoroalkyl- 
1,2-propylene oxide/ethylene glycol = 
1:0.58:0.14 
______________________________________ 
EXAMPLE 4 
Into a reactor was charged with agitation 1 mol of 
3-perfluoroalky11,2-propylene oxide with an epoxide equivalent of 440, 15 
mols of tetrahydrofuran and 0.358 mol of ethylene glycol. The resulting 
homogeneous monomer mixture was cooled with agitation under nitrogen to 
4.degree. C. A boron trifluoride/tetrahydrofuran complex (24 ml) was fed 
with agitation to the cooled mixture at a rate of 0.3 ml per minute; 
during which, the temperature to rise to a maximum of 48.degree. C. After 
completion of catalyst addition, heating and agitation were continued at 
70.degree. C. for 2 hours. To the agitated homogeneous reaction mass was 
added 280 ml of deionized water. After holding with agitation for 1 hour 
at 70.degree. C., 39.1 g calcium oxide powder was added, and heating and 
agitation were continued for another hour at 70.degree. C. The reaction 
product was then filtered and dried for about 2 hours at 
80.degree.-85.degree. C. under a pressure of 1300- 2000 Pa (10-15 mm Hg) 
giving rise to a straw-colored viscous oil. The copolyether glycol thus 
obtained had the following characteristics: 
(1) Number average molecular weight: 1779 
(2) Viscosity: 6.9 Pa.s at 40.degree. C. 
(3) Fluorine Content: 29.6 Wt % 
(4) Composition: 
______________________________________ 
By Weight 46.5% of 3-perfluoroalkyl-1,2-propylene 
oxide 
52.4% of tetrahydrofuran 
1.1% of ethylene glycol 
Mole Ratio Tetrahydrofuran/3-perfluoroalkyl- 
1,2-propylene oxide/ethylene glycol = 
1:0.14:0.03 
______________________________________ 
EXAMPLE 5 
Into a reactor was charged with agitation 1 mol of 
3-perfluoroalkyl-1,2-propylene oxide (epoxide equivalent 440), 3 mols of 
tetrahydrofuran, 1 mol of ethylene oxide and 0.28 mol of ethylene glycol. 
The agitated homogeneous monomers mixture was cooled under nitrogen to 
3.degree. C. before the addition of 15.7 ml of boron 
trifluoride-tetrahydrofuran complex at a rate of 0.15 ml per minute. The 
reaction mixture was continuously cooled with agitation so as to control 
the exotherm below 20.degree. C. After completion of catalyst addition, 
the reaction mass was agitated for 2 hours at 70.degree. C. Then 250 ml of 
deionized water was added to the agitated reaction mass . After holding 
with agitation for 1 hour at 70.degree. C., 31.3 g of calcium oxide powder 
were added, and heating and agitation were continued for another hour at 
70.degree. C. The reaction product was then filtered and dried for about 2 
hours at 80.degree.-85.degree. C. under a pressure of 1300-2000 Pa (10-15 
mm Hg), yielding a straw-colored viscous oil. The terpolyether glycol thus 
obtained had the following characteristics: 
(1) Number average molecular weight: 1612 
(2) Viscosity: 2.6 Pa.s at 40.degree. C. 
(3) Fluorine Content: 46.9 Wt % 
(4) Composition: 
______________________________________ 
By Weight 71.7% of 3-perfluoroalkyl-1,2-propylene 
oxide 
21.9% tetrahydrofuran 
6.4% ethylene oxide + ethylene glycol 
______________________________________ 
EXAMPLE 6 
Into a reactor was charged with agitation 1 mol of 
3-perfluoroalkyl-1,2-propylene oxide with an epoxide equivalent of 437, 1 
mol of epichlorohydrin and 0.4 mol of ethylene glycol. The agitated 
monomer mixture was cooled to 3.degree. C. under nitrogen before the 
addition of 11.4 ml of boron trifluoride/tetrahydrofuran complex at a rate 
of 0.15 ml per minute. To control the exotherm, intermittent cooling was 
supplied. After completion of catalyst addition, the reaction mass was 
agitated for 12 hours at 80.degree. C. To the agitated reaction mass was 
then added 220 ml of deionized water. After agitating for another hour at 
80.degree. C., the product was dried for about 2 hours at 
80.degree.-85.degree. C. under a pressure of 1300-2000 Pa (10-15 mm Hg) 
giving a yellowish, hazy oil. 
The copolyether glycol thus obtained had the following characteristics: 
(1) Number average molecular weight: 1352 
(2) Fluorine Content: 52.5 Wt % 
EXAMPLE 7 
Into a reactor was charged with agitation 1 mol of 
3-perfluoroalkyl-1,2-propylene oxide with an epoxide equivalent of 440, 
and 2.65 mols of tetrahydrofuran. The agitated monomer mixture was cooled 
to 3.degree. C. under nitrogen before the addition of 5.4 ml of 
fluosulfonic acid at a rate of 0.4 ml per minute, causing an exotherm to 
15.degree. C. After completion of the catalyst addition, the temperature 
of the reaction mass was slowly raised to 20.degree., 30.degree. and 
finally 40.degree. C. while continuing agitation. After holding the 
reaction mass with agitation for 5 hours at 40.degree. C., a total of 120 
ml of deionized water was added and agitation was continued for 1 hour at 
40.degree. C. To the reaction mass was then added 9 g of calcium oxide 
powder, and heating and agitation were continued for another hour at 
40.degree. C. The reaction product was then filtered and dried for about 2 
hours at 80.degree.-85.degree. C. under a pressure of 1300-2000 Pa (10-15 
mm Hg) giving a yellowish oil which partially crystallized on standing at 
room temperature. 
The copolyether glycol thus obtained had the following characteristics: 
(1) Number average molecular weight: 1278 
(2) Viscosity: 2.4 Pa.s at 60.degree. C. 
(3) Fluorine Content: 52.5 Wt % 
(4) Composition: 
______________________________________ 
By Weight 88.5% of 3-perfluoroalkyl-1,2-propylene 
oxide 
11.5% tetrahydrofuran 
Mole Ratio Tetrahydrofuran/3-perfluoroalkyl- 
1,2-propylene oxide = 1:1.26 
______________________________________ 
CONTROL 
A polyether glycol containing no fluorine was converted to a polyurethane 
in the following manner. Into a reaction vessel was charged 0.05 mol of a 
poly(tetramethylene ether glycol) [PTMEG] with a number average molecular 
weight of 1888, 0.15 mol of diphenylmethane-4,4'-diisocyanate, 0.1 mol of 
4-butanediol and 200 ml of dry dimethylformamide. To the agitated mixture 
under nitrogen atmosphere was added 1 drop of dibutyltin dilaurate 
catalyst. An exotherm was noticed immediately together with a rise in 
viscosity. After the exotherm subsided, the very viscous solution was 
heated for another hour at 85.degree. C. before being further diluted with 
dimethylformamide and/or tetrahydrofuran. The solution was cast onto a 
glass plate and allowed to dry for 4 hours at room temperature and 4 hours 
at 85.degree. C. to an elastic coating. The surface properties of the 
coating was determined by contact angle measurements using deionized water 
and hexadecane. The results are shown in Table I. 
EXAMPLE 8 
A blend of a non-fluorinated polyether glycol with a fluorine-containing 
polyether glycol was converted to a polyurethane in the following manner. 
Into a reaction vessel was charged 0.025 mol of a poly(tetramethylene 
ether glycol) [Mn(OH)=1888], 0.025 mol of the polyether glycol of Example 
3 [Mn(OH)=1719], 0.15 mol of diphenylmethane-4,4-diisocyanate, 0.1 mol of 
1,4-butanediol and 200 ml of dry dimethylformamide. The procedure 
described in the Control was used to make a coating, the surface 
properties of which are shown in Table 1. 
EXAMPLE 9 
The fluorine-containing polyether glycols of Examples 2, 3, 4 and 5 were 
converted to polyurethanes in the following manner. Into a reaction vessel 
was charged 0.05 mol of polyether glycol of Example 2 (Example 3, 4 and 5 
respectively) 0.15 mol of diphenylmethane-4,4,- diisocyanate, 0.1 mol of 
1,4-butanediol and 200 mol of dry dimethylformamide. The procedure 
described in the Control was used to make coatings, the surface properties 
of which are shown in Table 1. 
TABLE 1 
______________________________________ 
CONTACT ANGLES OF POLYURETHANE COATINGS 
Contact Angles 
Polyether (Advanced), Degrees 
Coating Glycol Type Deionized Water 
Hexadecane 
______________________________________ 
Control PTMEG 99 17 
Example 8 
Blend PTMEG/ 122 77 
Glycol of 
Example 3 
Example 9 
Glycol Example 2 
122 79 
Glycol Example 3 
114 71 
Glycol Example 4 
120 75 
Glycol Example 5 
116 74 
______________________________________ 
EXAMPLE 10 
Into a reaction vessel was charged with agitation 0.1 mol of polyether 
glycol of Example 3 and 0.2 mol of hexamethylene diisocyanate. The mixture 
was heated with agitation under nitrogen to 55.degree. C. Then one drop of 
dibutyltin dilaurate was added with agitation, causing an exotherm up to 
90.degree. C. The reaction mass was then held with agitation for 3 hours 
at 85.degree. C. to give a product having a free isocyanate content of 3.9 
as determined by the di-n-butylamine titration technique (Analytical 
Chemistry of Polyurethanes, Volume XVI, Part III, Wiley Interscience 1969, 
Pages 357-359). Then 5.9 parts of N-methyldiethanolamine were added to 
106.4 parts of the above prepolymer to give an isocyanate/hydroxyl mol 
ratio of 1 to 1. The resulting polymer was held with agitation for 17 
hours at 95.degree. C., and 1.5 g of 2-chloroacetamide were then added 
with agitation After heating with agitation for 2 hours at 125.degree. C., 
the polymer was cooled to 90.degree. C., and 2 g of acetic acid in 120 ml 
of preheated deionized water were added with agitation, followed by 2.8 g 
of 37% aqueous formaldehyde. The reaction mixture was agitated for an 
additional 1/2 hour at 90.degree. C. before being cooled to 50.degree. C. 
At that point 500 ml of acetone were added. Finally the acetone was 
stripped from the clear solution at 40.degree.-50.degree. C. under a 
pressure of 6,700-13,400 Pa (50-100 mm Hg) giving an aqueous 
cross-linkable polyurethane dispersion. Based on solids, the material 
contained 43.3 wt % of fluorine.