U.S. patent application number 10/790687 was filed with the patent office on 2004-09-09 for foaming compositions.
This patent application is currently assigned to Ausimont S.p.A.. Invention is credited to Basile, Giampiero, Girolomoni, Sauro, Musso, Ezio.
Application Number | 20040176489 10/790687 |
Document ID | / |
Family ID | 11380662 |
Filed Date | 2004-09-09 |
United States Patent
Application |
20040176489 |
Kind Code |
A1 |
Musso, Ezio ; et
al. |
September 9, 2004 |
Foaming compositions
Abstract
Use as foaming agents having a low environmental impact of
azeotropic or near azeotropic compositions using
difluoromethoxy-bis(difluoromethyl ether) and/or
1-difluroromethoxy-1,1,2,2-tetrafluoroethyl difluoromethyl
ether.
Inventors: |
Musso, Ezio; (Alessandria,
IT) ; Basile, Giampiero; (Alessandria, IT) ;
Girolomoni, Sauro; (Alessandria, IT) |
Correspondence
Address: |
ARENT FOX KINTNER PLOTKIN & KAHN
1050 CONNECTICUT AVENUE, N.W.
SUITE 400
WASHINGTON
DC
20036
US
|
Assignee: |
Ausimont S.p.A.
|
Family ID: |
11380662 |
Appl. No.: |
10/790687 |
Filed: |
March 3, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10790687 |
Mar 3, 2004 |
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09375239 |
Aug 16, 1999 |
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6753356 |
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Current U.S.
Class: |
521/97 ;
521/98 |
Current CPC
Class: |
C08J 2203/142 20130101;
C08J 2203/12 20130101; C08J 2203/14 20130101; C08J 2203/146
20130101; C08J 9/149 20130101 |
Class at
Publication: |
521/097 ;
521/098 |
International
Class: |
C08J 009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 19, 1998 |
IT |
MI98 A 001905 |
Claims
1. A process for foaming polyurethanes comprising: adding to
compositions used to make solid polymers azeotropic or near
azeotropic foaming agents compositions as substitutes for CFC 11 to
give a homogeneous foam having density of about 30 Kg/cm.sup.3,
said foaming agent compositions based on
di-fluoromethoxy-bis(difluoromethyl ether) and/or
1-difluoro-methoxy-1,1,- 2,2-tetrafluoroethyl difluoromethyl ether,
said foaming agent compositions essentially selected from the group
consisting of:
29 Composition % by weight IV) difluoromethoxy 1-99
bis(difluoromethyl ether) (HCF.sub.2OCF.sub.2OCF.sub.2H);
1,1,1,3,3-pentafluorobutane 99-1 (CF.sub.3CH.sub.2CF.sub.2CH.sub.3,
HFC 365mfc) V) difluoromethoxy 1-40 bis(difluoromethyl ether)
(HCF.sub.2OCF.sub.2OCF.sub.2H); 1,1,1,4,4,4-hexafluorobutane 99-60
(CF.sub.3CH.sub.2CH.sub.2CF.sub.3, HFC 365ffa)
wherein the difluoromethoxy-bis(difluoromethyl ether) part contains
up to 40% by weight of
1-difluoromethoxy-1,1,2,2-tetrafluoroethyldifluoromethyl ether.
2. The process of claim 1, wherein said foaming agent compositions
are selected from the group consisting of:
30 composition % by weight IV) difluoromethoxy 10-98
bis(difluoromethyl ether) (HCF.sub.2OCF.sub.2OCF.sub.2H);
1,1,1,3,3-pentafluorobutane 90-2 (CF.sub.3CH.sub.2CF.sub.2CH.sub.3,
HFC 365 mfc) V) difluoromethoxy 10-40 bis(difluoromethyl ether)
(HCF.sub.2OCF.sub.2OCF.sub.2H); 1,1,1,4,4,4-hexafluorobutane 90-60
(CF.sub.3CH.sub.2CH.sub.2CF.sub.3, HCF 356 ffa).
3. The process of claim 1, wherein said foaming agent compositions
are selected from the group consisting of:
31 composition % by weight D) difluoromethoxy 60% by wt.
bis(difluoromethyl ether) (HCF.sub.2OCF.sub.2OCF.sub.2H);
1,1,1,3,3-pentafluorobutane 40% by wt.
(CF.sub.3CH.sub.2CF.sub.2CH.sub.3, HFC 365 mfc) E) difluoromethoxy
20% by wt. bis(difluoromethyl ether)
(HCF.sub.2OCF.sub.2OCF.sub.2H); 1,1,1,4,4,4-hexafluorobutane 80% by
wt. (CF.sub.3CH.sub.2CH.sub.2CF.sub.3, HCF 356 ffa).
4. The process according to claim 1, wherein said compositions are
added in amounts in the range 1-15% by weight on the total
preparation.
5. The process according to claim 1, wherein said compositions are
used in combination with H.sub.2O and/or CO.sub.2.
6. The process according to claim 5, wherein the water amount is in
the range 0.5-7 parts by weight on one or hundred parts of
polyol.
7. The process according to claim 5, wherein the CO.sub.2 amount is
in the rage 0.6-10 parts by weight on one hundred parts of
polyol.
8. The process according to claim 5, wherein stabilizers for
radicalic decomposition reactions are added, the concentration of
which is in the range 0.1-5% by weight with respect to the foaming
agent.
9. Polyurethane polymer foaming compositions comprising, as blowing
agent substitutes of CFC-11 to give a homogeneous foam having
density of about 30 Kg/cm.sup.3, foaming agent azeotropic or near
azeotropic compositions selected from the group consisting of:
32 composition % by weight IV) difluoromethoxy 1-99
bis(difluoromethyl ether) (HCF.sub.2OCF.sub.2OCF.sub.2H);
1,1,1,3,3-pentafluorobutane 99-1 (CF.sub.3CH.sub.2CF.sub.2CH.sub.3,
HFC 365 mfc) V) difluoromethoxy 1-40 bis(difluoromethyl ether)
(HCF.sub.2OCF.sub.2OCF.sub.2H); 1,1,1,4,4,4-hexafluorobutane 99-60
(CF.sub.3CH.sub.2CH.sub.2CF.sub.3, HCF 356 ffa).
wherein the diflouromethoxy-bis (difluoromethyl ether) parts
contains up to 40% by weight of
1-difluoromethoxy-1,1,2,2-tetrafluoroethyldifluoromet- hyl
ether.
10. Polyurethane polymer foaming compositions according to claim 9
comprising foaming agent selected from the group consisting of:
33 composition % by weight D) difluoromethoxy 60% by wt.
bis(difluoromethyl ether) (HCF.sub.2OCF.sub.2OCF.sub.2H);
1,1,1,3,3-pentafluorobutane 40% by wt.
(CF.sub.3CH.sub.2CF.sub.2CH.sub.3, HFC 365 mfc) E) difluoromethoxy
20% by wt. bis(difluoromethyl ether)
(HCF.sub.2OCF.sub.2OCF.sub.2H); 1,1,1,4,4,4-hexafluorobutane 80% by
wt. (CF.sub.3CH.sub.2CH.sub.2CF.sub.3, HCF 356 ffa).
Description
[0001] The present invention relates to azeotropic or near
azeotropic compositions to be used as trichlorofluoromethane (CFC
11) substitutes in the foaming field.
[0002] More specifically the present invention relates to
azeotropic or near azeotropic mixtures characterized by zero ODP
(Ozone Depletion Potential), low GWP (Global Warming Potential) and
VOC (Volatile Organic Compounds) values.
[0003] The foamed polyurethanes represent a class of materials
widely used for applications concerning the furnishing, car and in
general transport, building and cooling industry.
[0004] Polyurethanes are polyaddition products between isocyanates
and polyols; depending on the precursor features, it is possible to
obtain flexible, rigid foams, or foams having intermediate
characteristics.
[0005] The former are used in the furnishing and car sector, while
rigid polyurethanes are widely used in the thermal insulation field
for building and cooling industry.
[0006] All the polyurethane foams require a foaming agent for their
preparation in order to obtain cellular structures, density,
mechanical and insulation properties suitable for any application
type.
[0007] As known, the common foaming agent used for the preparation
of foamed polyurethanes has been for a long time CFC 11.
[0008] CFCs and specifically CFC 11 have, however, the drawback to
show a high destroying power on the stratospheric ozone layer,
therefore, the production and commercialization have been subjected
to rules and then banned since Jan. 1, 1995.
[0009] In the foamed polyurethane field, the use versatility of
these products, which allows applications in different fields with
the use of suitable technologies and raw material formulations, has
made impossible the identification of a single product valid for
the replacement of CFC 11 in all applications.
[0010] The alternative solutions which now result widely used
foresee the use of hydrocarbons (n-pentane, iso-pentane and
cyclo-pentane) or of HCFC 141b (1,1-dichloro-1-fluoroethane).
[0011] Hydrocarbons, due to their high flammability, have not a
generalized use and require large investments to avoid fire and
explosion risks in plants using them. Furthermore, these foaming
agents constitute an atmospheric pollution source since, if exposed
to the sun light in the presence of nitrogen oxides, they undergo
oxidative degradation phenomena, with formation of the so called
ozone-rich "oxidizing smog". Due to this negative characteristic,
these products are classified as VOC compounds (Volatile Organic
Compound). HCFC 141b, which has been and is one of the most valid
substitutes for above applications, has however the drawback to be
moderately flammable and especially to be characterized by an ODP
value equal to 0.11 (CFC 11 has ODP=1) and therefore it has been
subjected to restricted use. There was a need to have available
substitutes able to furtherly limit or overcome the above mentioned
environmental and safety problems and which allow a simpler and
generalized use as foaming agents.
[0012] In a previous patent application in the name of the
Applicant foaming compositions using specific hydrofluoropolyethers
have been described. However said hydrofluoropolyethers are very
expensive for their obtainment process.
[0013] The need was therefore felt to have available foaming
compositions based on said hydrofluoropolyethers (HFPE) having an
azeotropic or near azeotropic behaviour as to be used as substitute
of CFC 11 but with low environmental impact expressed in terms of
ODP, GWP and VOC values.
[0014] The Applicant has unexpectedly found that the
hydrofluoropolyether-based mixtures (HFPE), object of the present
invention, are characterized by chemical-physical properties such
to be suitable as substitutes of CFC 11, they have an environmental
impact expressed in terms of ODP equal to zero and low GWP and VOC
values.
[0015] It is an object of the present invention azeotropic or near
azeotropic compositions to be used as foaming agents having a low
environmental impact, consisting essentially of:
1 composition % by weight general preferred I) difluoromethoxy 1-95
25-95 bis(difluoromethyl ether) (HCF.sub.2OCF.sub.2OCF.sub.2H);
n-pentane 99-5 75-5 II) difluoromethoxy 1-99 25-98
bis(difluoromethyl ether) (HCF.sub.2OCF.sub.2OCF.sub.2H);
iso-pentane 99-1 75-2 III) difluoromethoxy 1-60 20-60
bis(difluormethyl ether) (HCF.sub.2OCF.sub.2OCF.sub.2H); dimethyl
ketone (acetone) 99-40 80-40 IV) difluoromethoxy 1-99 10-98
bis(difluoromethyl ether) (HCF.sub.2OCF.sub.2OCF.su- b.2H);
1,1,1,3,3-pentafluorobutane 99-1 90-2
(CF.sub.3CH.sub.2CF.sub.2CH.sub.3, HFC 365 mfc) V) difluoromethoxy
1-40 10-40 bis(difluoromethyl ether)
(HCF.sub.2OCF.sub.2OCF.sub.2H); 1,1,1,4,4,4-hexafluorobutane 99-60
90-60 (CF.sub.3CH.sub.2CH.sub.2CF.sub.3, HFC 356 ffa) VI)
difluorometoxy 1-96 25-96 bis(difluoromethyl ether)
(HCF.sub.2OCF.sub.2OCF.sub.2H); methoxymethyl methylether 99-14
75-14 VII) difluoromethoxy 30-99 35-98 bis(difluoromethyl ether)
(HCF.sub.2OCF.sub.2OCF.sub.2H); n-hexane 70-1 65-2 VIII)
1-difluoromethoxy 1-93 25-93 1,1,2,2-tetrafluoroethyl
difluoromethyl ether (HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H);
n-pentane 99-7 75-7 IX) 1-difluoromethoxy 30-99 50-98
1,1,2,2-tetrafluoroethyl difluoromethyl ether
(HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H); dimethyl ketone (acetone)
70-1 50-2 X) 1-difluoromethoxy 15-99 25-98 1,1,2,2-tetrafluoroethyl
difluoromethyl ether (HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H);
n-hexane 85-1 75-2 XI) 1-difluoromethoxy 5-99 10-98
1,1,2,2-tetrafluoroethyl difluoromethyl ether
(HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H); ethyl alcohol 95-1 90-2
[0016] Difluoromethoxy-bis(difluoromethyl ether) is indicated as
HFPE1; 1-difluoromethoxy-1,1,2,2-tetrafluoroethyl difluoromethyl
ether is indicated as HFPE2. More specifically the azeotropic
compositions, in correspondence of which an absolute minimum or
maximum in the boiling temperature at the pressure of 1.013 bar
with respect to the pure products is noticed, are defined as
follows:
2 Compositions are defined within +/-2% by weight A)
difluoromethoxy-bis(difluoromethyl ether) 62% by wt.
(HCF.sub.2OCF.sub.2OCF.sub.2H); n-pentane 38% by wt. B)
difluoromethoxy-bis(difluoromethyl ether) 63% by wt.
(HCF.sub.2OCF.sub.2OCF.sub.2H); iso-pentane 36% by wt. C)
difluoromethoxy-bis(difluoromethyl ether) 42% by wt.
(HCF.sub.2OCF.sub.2OCF.sub.2H); dimethyl ketone (acetone) 58% by
wt. D) difluoromethoxy-bis(difluoromethyl ether) 60% by wt.
(HCF.sub.2OCF.sub.2OCF.sub.2H); 1,1,1,3,3-pentafluorobuta- ne 40%
by wt. (CF.sub.3CH.sub.2CF.sub.2CH.sub.3, HFC 365 mfc) E)
difluoromethoxy-bis(difluoromethyl ether) 20% by wt.
(HCF.sub.2OCF.sub.2OCF.sub.2H); 1,1,1,4,4,4-hexafluorobutane 80% by
wt. (CF.sub.3CH.sub.2CH.sub.2CF.sub.3, HFC 356 ffa) F)
difluoromethoxy-bis(difluoromethyl ether) 59% by wt.
(HCF.sub.2OCF.sub.2OCF.sub.2H); methoxymethyl methyl ether 41% by
wt. G) difluoromethoxy-bis(difluoromethyl ether) 75% by wt.
(HCF.sub.2OCF.sub.2OCF.sub.2H); n-hexane 25% by wt. H)
1-difluoromethoxy-1,1,2,2-tetrafluoroethyl 61% by wt.
difluoromethyl ether (HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H);
n-pentane 39% by wt. I) 1-difluoromethoxy-1,1,2,2-tetrafluoroet-
hyl 79% by wt. difluoromethyl ether
(HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H); dimethyl ketone (acetone)
21% by wt. L) 1-difluoromethoxy-1,1,2,2-tetrafluoroethyl 74% by wt.
difluoromethyl ether (HCF.sub.2OCF.sub.2CF.sub.2OCF.s- ub.2H);
n-hexane 26% by wt. M) 1-difluoromethoxy-1,1,2,2-te- trafluoroethyl
95% by wt. difluoromethyl ether
(HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H); ethyl alcohol 5% by wt.
[0017] The mixtures having an azeotropic or near azeotropic
behaviour are of great importance in order to avoid fractionation
or considerable variations of their composition during handling,
dosage and storage operations wherein accidental losses can take
place due to liquid evaporation and consequently variations of the
composition of the fluid.
[0018] The composition variations which take place in all the cases
when non azeotropic mixtures are used, involve deviations of the
foaming agent performances and the need to make suitable refillings
in order to restore the original composition and therefore the
mixture chemical-physical characteristics.
[0019] Furthermore, when the non azeotropic or non near-azeotropic
compositions contain more volatile flammable components, the vapour
phase becomes rich in such component until reaching the
flammability limit, with evident risks for the use safety.
Likewise, when the flammable component is less volatile, it
concentrates in the liquid phase giving rise to a flammable
liquid.
[0020] Mixtures having azeotropic or near azeotropic behaviour
avoid the above disadvantage even when a flammable compound is
present.
[0021] An azeotrope is a particular composition which has singular
chemical-physical, unexpected and unforeseeable properties of which
the most important ones are reported hereinafter.
[0022] An azeotrope is a mixture of two or more fluids which has
the same composition in the vapour phase and in the liquid one when
it is in equilibrium under determined conditions.
[0023] The azeotropic composition is defined by particular
temperature and pressure values; in these conditions the mixtures
undergo phase changes at constant composition and temperature as
pure compounds.
[0024] A near azeotrope is a mixture of two or more fluids which
has a vapour composition substantially equal to that of the liquid
and undergoes phase changes without substantially modifying the
composition and temperature. A composition is near azeotropic when,
after evaporation at a constant temperature of 50% of the liquid
initial mass, the percent variation of the vapour pressure between
the initial and final composition results lower than 10%; in the
case of an azeotrope, no variation of the vapour pressure between
the initial composition and the one obtaind after the 50% liquid
evaporation is noticed.
[0025] Azeotropic or near azeotropic mixtures belong to the cases
showing meaningful, both positive and negative, deviations from the
Raoult law. As known to the skilled in the art such law is valid
for ideal systems.
[0026] When such deviations are sufficiently marked, the mixture
vapour pressure in the azeotropic point must therefore be
characterized by values either lower or higher than those of the
pure compounds.
[0027] It is evident that, if the mixture vapour pressure curve
shows a maximum, this corresponds to a minimum of boiling
temperature; viceversa to a vapour pressure minimum value, a
maximum of boiling temperature corresponds.
[0028] The azeotropic mixture has only one composition for each
temperature and pressure value.
[0029] However, by changing temperature and pressure, more
azeotropic compositions starting from the same components can be
obtained.
[0030] For example, the combination of all the compositions of the
same components which have a minimum or a maximum in the boiling
temperature at different pressure levels form an azeotropic
composition field.
[0031] Hydrofluoropolyethers used in the compositions of the
present invention: HFPE1 and HFPE2, are obtained by decarboxylation
processes of the alkaline salts obtained by hydrolysis and
salification of the corresponding acylfluorides, using processes
known in the art. For example, decarboxylation is carried out in
the presence of hydrogen-donor compounds, for example water, at
temperatures of 1400-170.degree. C. and under a pressure of at
least 4 atm. See for example EP 695,775 and the examples reported
therein; this patent is herein incorporated by reference.
[0032] The characteristics of the two hydrofluoropolyethers used in
the compositions of the present invention are reported in Table 1
in comparison with CFC 11 and HCFC 141b as regards ODP and GWP.
[0033] It has been found that the near azeotropic compositions of
points II, III, IV, V, VI, remain near azeotropic also when a
portion of difluoromethoxy-bis(difiuoromethyl ether) is substituted
with 1-difluoromethoxy-1,1,2,2-tetrafluoroethyldifluoromethyl
ether, up to 40% by weight. They are used as foaming agents.
[0034] The same for compositions of points IX and X when a portion
of 1-difluoromethoxy-1,1,2,2-tetrafluoroethyl difluoromethyl ether
is substituted by difluoromethoxy-bis(difluoromethyl ether), up to
40% by weight. They are used as foaming agents
[0035] The same for compositions of points I and VII wherein a
portion of difluoromethoxy-bis(difluoromethyl ether) is replaced by
1-difluoromethoxy-1,1,2,2-tetrafluoroethyldifluoromethyl ether up
to 50% by weight. They are used as foaming agents.
[0036] Likewise the compositions of points VIII and X, wherein a
portion of 1-difluoromethoxy-1,1,2,2-tetrafluoroethyl
difluoromethyl ether is replaced by
difluoromethoxy-bis(difluoromethyl ether) up to 50% by weight.
[0037] Another object of the present invention are ternary near
azeotropic compositions essentially consisting of:
3 % by weight XII) difluoromethoxy-bis(difluoromethyl ether) 1-64
(HCF.sub.2OCF.sub.2OCF.sub.2H); 1,1,1,3,3-pentafluorobutane 98-1
(CF.sub.3CH.sub.2CF.sub.2CH.sub.3, HFC 365 mfc) hydrocarbon 1-35
XIII) difluoromethoxy-bis(difluoromethyl ether) 1-22
(HCF.sub.2OCF.sub.2OCF.sub.2H); 1,1,1,4,4,4-hexafluorobutane 98-43
(CF.sub.3CH.sub.2CH.sub.2CF.su- b.3, HFC 356 ffa) hydrocarbon
1-35
[0038] used as foaming agents.
[0039] Among hydrocarbons, n-pentane and iso-pentane are preferred
preferably in the range 1-20% by weight.
[0040] A further object of the present invention are azeotropic or
near azeotropic compositions to be used as foaming agents, as
described at points from I) to XIII) and from A) to M), wherein a
portion of HFPE1 and/or HFPE2 is replaced by hydrofluoropoly-ethers
having the same structure of HFPE1 or HFPE2 but boiling point in
the range of 5.degree.-80.degree. C. Therefore, it is possible to
refer to fluids consisting essentially of HFPE1 and/or HFPE2.
[0041] The compositions mentioned at points I, II, IV, V, VI, VII,
VIII, X, A, B, D, E, F, G, H and L are preferred as foaming agents
for foamed polyurethanes, and represent a good substitute for CFC
11 for their good balance of foaming properties.
[0042] The polyurethane foams produced with the azeotropic or near
azeotropic compositions of the present invention are obtained by
reaction between polyols and isocyanates in the presence of
catalysts and other additives usually employed for preparing
polyurethane foams, by using known methods. Depending on the
desired foams to be prepared, polyols and isocyanates will be used
such as to obtain in combination with the present invention
compositions the chemical-physical and mechanical characteristics
required for each specific application.
[0043] Another advantage of the present invention, in the
polyurethane foam preparation field, is that to be able to modulate
the affinity of the mentioned mixtures with the different types of
polyols used for the different applications in order to obtain the
desired manufactured article features in terms of density,
mechanical and insulation properties, with the possibility,
therefore, of a more generalized use of the foaming agent which
changes, depending on the applications, only the composition.
[0044] Azeotropic or near azeotropic compositions are added to the
formulations in amounts in the range 1-15% by weight on the total
preparation, including the same foaming agent. Preferably 1.5-10%
by weight, more preferably 1.5-8% by weight on the total
formulation for the foam preparation.
[0045] The mentioned compositions can be advantageously used in
combination with H.sub.2O and/or CO.sub.2, for example gas
phase.
[0046] In particular they can be used in combination with water, as
in the past it was done for the CFC 11, CF 11 "reduce"-based
formulations and today it is commonly done for the HCFC 141b-based
formulations.
[0047] Water can be added to the formulations in amount in the
range 0.5-7, preferably 1-6, and more preferably 1-4 parts by
weight on one hundred parts of polyol.
[0048] The CO.sub.2 can be used in concentrations in the range
0.6-10 parts, preferably 1-8 parts by weight on one hundred parts
by weight of polyol.
[0049] The mixtures of the invention can be used in combination
with stabilizing agents in order to limit the radicalic
decomposition reactions which, as known, are favoured by the
temperature, by the presence of metals and by very reactive
polyurethane formulations (for example due to polyols and/or
catalysts of basic nature used in such formulations).
[0050] The degradation reactions especially concerning the mixtures
containing HFC 356 ffa and 365 mfc, can be prevented or reduced by
the use of nitroparaffins and/or organic substances having double
bond double bonds in the molecule.
[0051] The stabilizing agents are generally used in amounts of
0.1-5% by weight.
[0052] Furthermore the compositions described at points I, II, III,
VII, VIII, IX, X, XI, XII, XIII, A, B, C, G, H, I, L, M can be used
for the preparation of thermoplastic foams. These compositions can
be used as foaming agents above all for foamed polystyrenes and
polyethylenes; these materials were prepared in the past by using,
as main foaming agents, dichlorofluoromethane (CFC 12), CFC 11 or
mixtures thereof. At present polystyrenes and polyethylenes for
thermal insulation applications are produced by using HCFC-based
mixtures (HCFC 22: chlorotrifluoro methane; HFC 142b: 1 chloro-1,1
difluoro ethane), which however have been restricted for their
environmental impact. The above compositions of the invention used
for the preparation of foamed polystyrenes and polyethylenes can be
advantageously used in combination with foaming agents selected
from CO.sub.2, HFC 134a (1,1,1,2 tetrafluoroethane), HFC 227ea, HFC
152a (1,1 difluoroethane), HFC 236ea (1,1,1,2,3,3
hexafluoropropane) and their binary mixtures. The latter can be
used in amount up to 95% by weight of the foaming agent. The amount
of the foaming agent to be used for the foamed thermoplastic
polymer synthesis is in the range 5-30% by weight on the
thermoplastic polymer.
[0053] The following examples are given for illustrative but not
limitative purpose of the present invention.
EXAMPLE 1
[0054] Azeotropic or Near Azeotropic Behaviour Evaluation
[0055] The mixture of known composition and weight is introduced in
a small glass cell, previously evacuated, having an internal volume
equal to about 20 cm.sup.3, equipped with metal connections,
feeding valve and a pressure transducer to evaluate the system
vapour pressure.
[0056] The filling volumetric ratio is initially equal to about
0.8% v.
[0057] The cell is introduced in a thermostatic bath and the
temperature is slowly changed until obtaining a vapour pressure
equilibrium value equal to 1.013 bar. The corresponding temperature
is recorded and it represents the mixture boiling temperature at
the 1.013 bar pressure.
[0058] The temperature is measured close to the equilibrium cell
with a thermometer the accuracy of which is equal to
+/-0.01.degree. C.; particular attention was paid so that the
external temperature measured in the bath is really the internal
one of the cell.
[0059] By changing the mixture composition it is possible to
estimate possible deviations with respect to the ideality and
therefore to identify the azeotropic composition which, as said,
will be characterized by an absolute minumum or maximum with
respect to the pure components.
[0060] In order to confirm the azeotropic or near azeotropic
behaviour, the mixture characterized by a minumum or a maximum in
the boiling temperature and others identified close to the
azeotrope were subjected to evaporation test at the azeotrope
constant temperature.
[0061] The cell content is removed at constant temperature by
evaporation until having a loss corresponding to 50% by weight of
the initial amount.
[0062] From the evaluation of the initial and final pressure the
percent variation of the vapour pressure is calculated: if the
decrease is equal to zero the mixture in those conditions is an
azeotrope, if the decrease is <10% its behaviour is of a near
azotrope.
[0063] It is known that a near azetropic mixture has a behaviour
closer and closer to a true azeotrope if the percent variation is
lower and lower and near zero.
[0064] As a further confirmation of the azeotropic and near
azeotropic behaviour, together with the above reported evaluations,
analyses of the composition of some mixtures object of the present
invention, have been carried out by gaschromatographic method
before and after the evaporation test.
[0065] The azeotropic mixtures maintain unchanged, within the
limits of the error of the analytical methods, the composition
after the liquid evaporation, while in the case of near azeotropic
systems, limited composition variations are observed.
[0066] In all the measurements reported in Tables from 2 to 13 the
visual observation of the liquid phase at its normal boiling
temperature has at any rate shown that no phase separations took
place and that the solutions were limpid and homogeneous.
4TABLE 1 Chemical - physical and toxicological characteristics of
hydrofluoropolyethers Chemical formula CCl.sub.3F
CCl.sub.2FCH.sub.3 HCF.sub.2OCF.sub.2OCF.sub- .2H
HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H CFC 11 HCFC 141b Molecular
mass 184.04 234.05 137.37 116.94 ODP CFC 11 = 1 0 0 1 0.11 GWP
<10 <10 55 10.8 lifetime, years
[0067]
5TABLE 2 boiling temperature evaluation at the pressure of 1.013
bar HCF.sub.2OCF.sub.2OCF.sub.2H/n-pentane binary mixture
COMPOSITION BOILING TEMPERATURE HCF.sub.2OCF.sub.2OCF.sub.2H (% by
weight) (.degree. C.) 0 35.79 12.6 26.42 25.9 23.00 50.0 21.45 61.9
21.32 74.9 21.35 83.4 21.49 87.0 21.70 95.6 25.18 100 35.39
[0068]
6TABLE 2a evaluation of the azeotropic and near azeotropic
behaviour by determination of the vapour pressure percent variation
after evaporation of 50% of the initial liquid mass Initial
composition (% by wt.) HCF.sub.2OCF.sub.2OCF.sub.2H/ Temperature
Initial pressure .DELTA.P/P .times. 100 n-pentane.backslash.
(.degree. C.) (bar) (%) 61.9/38.1 21.32 1.013 0 50.3/49.7 21.32
1.010 2.47 84.3/15.7 21.32 1.006 3.08
[0069]
7TABLE 3 evaluation of the boiling temperature at the pressure of
1.013 bar HCF.sub.2OCF.sub.2OCF.sub.2H/iso-- pentane binary mixture
COMPOSITION BOILING TEMPERATURE HCF.sub.2OCF.sub.2OCF.sub.2H (% by
wt.) (.degree. C.) 0 27.18 14.2 21.02 20.4 20.00 39.5 17.70 61.0
17.40 63.1 17.35 80.1 17.68 90.4 19.80 100 35.39
[0070]
8TABLE 4a evaluation of the azeotropic and near azeotropic
behaviour by determination of the vapour pressure percent variation
after evaporation of 50% of the initial liquid mass Initial
composition (% by wt.) HCF.sub.2OCF.sub.2OCF.sub.2H/ Temperature
Initial pressure .DELTA.P/P .times. 100 iso-pentane (.degree. C.)
(bar) (%) 63.0/37.0 17.35 1.013 0 39.0/61.0 17.35 1.003 1.49
79.8/20.2 17.35 1.003 4.79
[0071]
9TABLE 4 evaluation of the boiling temperature at the pressure of
1.013 bar HCF.sub.2OCF.sub.2OCF.sub.2H/acet- one binary mixture
COMPOSITION HCF.sub.2OCF.sub.2OCF.sub.- 2H BOILING TEMPERATURE (%
by wt.) (.degree. C.) 0 56.50 28.1 57.88 41.7 58.11 51.0 57.98 61.2
56.63 74.8 53.62 100 35.39
[0072]
10TABLE 4a evaluation of the azeotropic and near azeotropic
behaviour by determination of the vapour pressure percent variation
after evaporation of 50% of the initial liquid mass. New
composition after evaportion of 50% by weight Initial composition
of the liquid .DELTA.P/ (% by wt.) Initial (% by wt.) P .times.
HCF.sub.2OCF.sub.2OCF.sub- .2H/ Temperature pressure
HCF.sub.2OCF.sub.2OCF.sub.2H/ 100 acetone (.degree. C.) (bar)
acetone (%) 41.7/58.3 58.11 1.013 41.8/58.2 0 28.0/72.0 58.11 1.021
31.1/68.9 0.88 50.4/49.6 58.11 1.019 49.7/50.3 1.37
[0073]
11TABLE 5 evaluation of the boiling temprature at the pressure of
1.013 bar HCF.sub.2OCF.sub.2OCF.sub.2H/HFC 365 mfc binary mixture
COMPOSITION BOILING TEMPERATURE HCF.sub.2OCF.sub.2OCF.sub.2H (% by
wt.) (.degree. C.) 0 40.09 10.0 36.89 20.0 34.92 30.0 33.71 40.1
33.01 50.1 32.66 60.1 32.60 75.0 33.13 80.0 33.54 100 35.39
[0074]
12TABLE 5a evaluation of the azeotropic and near azeotropic
behaviour by determination of the vapour pressure percent variation
after evaporation of 50% of the initial liquid mass Initial
composition (% by wt.) HCF.sub.2OCF.sub.2OCF.sub.2H/ Temperature
Initial pressure .DELTA.P/P .times. 100 HFC 365mfc (.degree. C.)
(bar) (%) 60.1/39.9 32.60 1.013 0 21.0/78.9 32.60 0.937 5.21
82.1/17.9 32.60 0.968 7.73
[0075]
13TABLE 6 evaluation of the boiling temperature at the pressure of
1.013 bar HCF.sub.2OCF.sub.2OCF.sub.2H/HFC 356 ffa binary mixture
COMPOSITION BOILING TEMPERATURE HCF.sub.2OCF.sub.2OCF.sub.2H (% by
wt.) (.degree. C.) 0 24.71 10.1 24.16 19.9 24.05 29.9 24.22 40.0
24.65 49.9 25.29 60.1 26.24 70.1 27.60 80.1 29.65 100 35.39
[0076]
14TABLE 6a evaluation of the azeotropic and near azeotropic
behaviour by determination of the vapour pressure percent variation
after evaporation of 50% of the initial liquid mass Initial
composition (% by wt.) HCF.sub.2OCF.sub.2OCF.sub.2H/ Temperature
Initial pressure .DELTA.P/P .times. 100 HFC 356 ffa (.degree. C.)
(bar) (%) 19.9/80.1 24.05 1.013 0 4.2/95.8 24.05 1.000 0.41
38.2/61.8 24.05 0.994 2.21
[0077]
15TABLE 7 evaluation of the boiling temperature at the pressure of
1.013 bar HCF.sub.2OCF.sub.2OCF.sub.2H/meth- oxymethyl methyl ether
binary mixture COMPOSITION BOILING TEMPERATURE,
HCF.sub.2OCF.sub.2OCF.sub.2H, % by wt. .degree. C. 0 41.96 20.1
42.80 27.5 43.05 38.1 43.40 50.6 43.78 59.1 43.74 60.2 43.76 65.0
43.53 72.1 42.95 78.7 41.66 100 35.39
[0078]
16TABLE 7a evaluation of the azeotropic and near azeotropic
behaviour by determination of the vapour pressure percent variation
after evaporation of 50% of the initial liquid mass Initial
composition (% by wt.) HCF.sub.2OCF.sub.2OCF.sub.2H/ methoxymethyl
Temperature Initial pressure .DELTA.P/P .times. 100 methyl ether
(.degree. C.) (bar) (%) 59.1/40.9 43.74 1.013 0 72.1/27.9 43.74
1.045 2.39 27.5/72.5 43.74 1.041 2.02
[0079]
17TABLE 8 evaluation of the boiling temperature at the pressure of
1.013 bar HCF.sub.2OCF.sub.2OCF.sub.2H/n-he- xane binary mixture
COMPOSITION BOILING TEMPERATURE HCF.sub.2OCF.sub.2OCF.sub.2H (% by
wt.) (.degree. C.) 0 68.00 15.4 43.86 34.0 35.15 50.8 33.12 65.6
32.42 74.7 32.10 78.1 32.15 90.1 32.22 100 35.39
[0080]
18TABLE 8a evaluation of the azeotropic and near azeotropic
behaviour by determination of the vapour pressure percent variation
after evaporation of 50% of the initial liquid mass Initial
composition (% by wt.) HCF.sub.2OCF.sub.2OCF.sub.2H/ Temperature
Initial pressure .DELTA.P/P .times. 100 n-hexane (.degree. C.)
(bar) (%) 74.7/25.3 32.10 1.013 0 65.6/34.4 32.10 1.006 0.60
90.1/9.9 32.10 1.011 0.89
[0081]
19TABLE 9 evaluation of the boling temperature at the pressure of
1.013 bar HCF.sub.2OCF.sub.2CF.sub.2OCF.sub- .2H/n-pentane binary
mixture COMPOSITION HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H BOILING
TEMPERATURE (% by wt.) (.degree. C.) 0 35.79 17.3 31.75 29.1 31.52
60.8 31.2 68.0 31.04 72.1 31.08 74.3 31.15 79.3 31.25 84.3 31.77
93.4 35.83 100 58.21
[0082]
20TABLE 9a azeotropic and near azeotropic behaviour evaluation by
determination of the vapour pressure percent variation after
evaporation of 50% of the initial liquid mass Initial composition
(% by wt.) HCF.sub.2OCF.sub.2CF.su- b.2OCF.sub.2H/ Temperature
Initial pressure .DELTA.P/P .times. 100 n-pentane (.degree. C.)
(bar) (%) 60.8/39.2 31.02 1.013 0 17.3/82.7 31.02 1.002 4.59
74.3/25.7 31.02 1.008 4.36
[0083]
21TABLE 10 boiling temperature evaluation at the pressure of 1.013
bar HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H/- acetone binary mixture
COMPOSITION BOILING TEMPERATURE
HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H (% by wt.) (.degree. C.) 0
56.50 15.5 56.83 30.8 58.23 40.7 59.45 58.6 62.87 70.0 65.04 79.4
65.96 85.5 65.28 89.9 64.41 100 58.21
[0084]
22TABLE 10a azeotropic and near azeotropic behaviour evaluation by
determination of the vapour pressure percent variation after
evaporation of 50% of the initial liquid mass New composition after
liquid evaporation of Initial composition 50% by weight (% by wt.)
Initial HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H/
HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H/ pressure acetone .DELTA.P/P
.times. 100 acetone Temperature (.degree. C.) (bar) (% by wt.) (%)
79.5/20.5 65.96 1.013 79.3/20.7 0 69.5/30.5 65.96 1.044 73.9/26.1
2.78 84.8/15.2 65.96 1.035 82.5/17.5 2.90
[0085]
23TABLE 11 boiling temperature evaluation at the pressure of 1.013
bar HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H/- n-hexane binary mixture
COMPOSITION BOILING TEMPERATURE
HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H (% by wt.) (.degree. C.) 0
68.00 20.6 56.24 39.7 48.81 59.9 46.74 73.8 46.66 78.7 46.76 89.9
49.00 100 58.21
[0086]
24TABLE 11a azeotropic and near azeotropic behaviour evaluation by
determination of the vapour pressure percent variation after
evaporation of 50% of the initial liquid mass Initial composition
(% by wt.) HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H/ Temperature
Initial pressure .DELTA.P/P .times. 100 n-hexane (.degree. C.)
(bar) (%) 73.8/26.2 46.66 1.013 0 39.8/60.2 46.66 0.938 7.57
89.9/10.1 46.66 0.935 8.02
[0087]
25TABLE 12 boiling temperature evaluation at the pressure of 1.013
bar HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H/- ethyl alcohol binary
mixture COMPOSITION BOILING TEMPERATURE
HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H (% by wt.) (.degree. C.) 0
78.50 20.6 72.35 48.9 63.70 62.6 60.12 80.0 57.33 89.7 56.07 94.7
55.65 98.0 55.75 99.0 56.02 100 58.21
[0088]
26TABLE 12a azeotropic and near azeotropic behaviour evaluation by
determination of the vapour pressure percent variation after
evaporation of 50% of the initial liquid mass New composition after
evaporation of 50% by weight of the Initial composition liquid (%
by wt.) Initial (% by wt.) HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2- H/
Temperature pressure HCF.sub.2OCF.sub.2CF.sub.2OCF.sub.2H/
.DELTA.P/P .times. 100 ethyl alcohol (.degree. C.) (bar) ethyl
alcohol (%) 94.7/5.3 55.65 1.013 95.0/5.0 0 79.4/20.6 55.65 0.954
75.6/24.4 1.26 99.0/1.0 55.65 1.005 99.3/0.7 2.99
[0089]
27TABLE 13 evaluation of the azeotropic behaviour of ternary
mixtures by determination of the vapour pressure percent variation
after evaporation of 50% of the initial liquid mass Ternary
mixtures Initial composition (% by wt) Boiling
HCF.sub.2OCF.sub.2OCF.sub.2H/HCF.sub.2OCF.sub.2CF.sub.2O-
CF.sub.2H/ temperature Initial pressure .DELTA.P/P .times. 100
acetone (.degree. C.) (bar) (%) 12.0/18.0/70.0 57.75 1.013 3.16
HCF.sub.2OCF.sub.2OCF.sub.2H/HCF.sub.2OCF.sub.2CF.sub.2OCF.su- b.2H
25.50 1.013 0.30 n-pentane 30.0/20.0/50.0
EXAMPLE 2
[0090] Use of HFPE-Based Mixtures as Foaming Agents for the
Preparation of Rigid Polyurethanes
[0091] Foams have been prepared according to the following
procedure:
[0092] In a polyethylene cylindrical container (diameter 12 cm;
height 18 cm) 100 g of polyol, the required water amount for each
kind of formualtion and the foaming agent used for the test, are
introduced.
[0093] The content is mixed with mechanical stirrer for one minute
at the rate of 1900 rpm, then isocyanate is added and stirring is
continued at the same speed for 15 seconds.
[0094] The foam is allowed to freely expand until the completion of
the reaction.
[0095] A foam portion is drawn in the central part of the foam for
the visual observation of the homogeneity, of the cellularity
properties of the foam and for the density determination.
[0096] The data are reported in Table 15 in comparison with those
obtained with CFC 11 and HCFC 141b (.alpha. and .beta. comparative
examples).
28TABLE 14 Example Example .alpha. .beta. Example Example Example
(comp) (comp) .gamma. .delta. .epsilon. Polyol 100 100 100 100 100
polyether (g) Water 2 2 2.6 2.7 2.6 pbw (g) Aminic 2.5 2.5 2.5 2.5
2.5 catalyst .diamond. pbw (g) CFC 11 30* pbw (g) HCFC 141b
28.sctn. pbw (g) HFPE1/ 29.8* HFC 365mfc (60/40) pbw (g) HFPE1/
28.5* HFC 356ffa (20) (80) pbw (g) HFPE1/ 33* HFPE2/ n-pentane (18)
(72) (10) pbw (g) ISO- 160 160 170 175 170 CYANATE pbw (g) Density
30 29.7 30.0 29.8 30.0 kg/m.sup.3 Foam GOOD GOOD GOOD GOOD GOOD
appearance HFPE1 = HCF.sub.2OCF.sub.2OCF.sub.2H HFPE2 =
HCF.sub.2OCF.sub.2CF.sub.2OC- F.sub.2H *: non flammable .sctn.:
flammable : polyol polyether with a number of hydroxyl equal to 500
mg KOH/g and containing silicone surfactant .diamond.: N,N-dimethyl
cyclohexylamine : Polymeric methylendiphenylisocyanate (MDI)
--DESMODUR 44V20 by Bayer pbw: parts by weight per 100 g of
polyol
[0097] The HFPE-based mixtures allow to obtain polyurethane foams
with good homogeneity and cellularity characteristics with
densities similar to the reference products.
[0098] Sufficiently low densities (about 30 Kg/m.sup.3) are
obtained with amounts of fluorinated foaming agent and water
comparable with the amounts used in the reference formulations with
CFC 11 and HCFC 141b.
[0099] A further advantage given by the mixtures containing HFPE is
that to eliminate or limit the inflammability due to the other
flammable components present in the mixture (n-pentane, HFC 365
mfc, HFC 356 ffa) with remarkable advantages in terms of foaming
agent handling and in terms of reaction with fire of the final
polyurethanic manufactured articles.
* * * * *