Foaming compositions

Details Foaming compositions Foaming compositions

1999-08-16

2004-06-22

Sergent, Rabon (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Cellular products or processes of preparing a cellular...

C252S067000, C252S068000, C252S364000, C510S408000, C510S415000, C521S087000, C521S088000, C521S097000, C521S098000, C521S113000, C521S117000, C521S130000, C521S131000

Reexamination Certificate

active

06753356

ABSTRACT:

The present invention relates to azeotropic or near azeotropic compositions to be used as trichlorofluoromethane (CFC 11) substitutes in the foaming field.
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.
The foamed polyurethanes represent a class of materials widely used for applications concerning the furnishing, car and in general transport, building and cooling industry.
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.
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.
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.
As known, the common foaming agent used for the preparation of foamed polyurethanes has been for a long time CFC 11.
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.
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.
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).
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 90 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.
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.
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.
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.
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:
composition
% by weight
general
preferred
I)
difluoromethoxy
 1-95
25-95
bis(difluoromethyl ether)
(HCF
2
OCF
2
OCF
2
H);
n-pentane
99-5 
75-5 
II)
difluoromethoxy
 1-99
25-98
bis(difluoromethyl ether)
(HCF
2
OCF
2
OCF
2
H);
iso-pentane
99-1 
75-2 
III)
difluoromethoxy
 1-60
20-60
bis(difluormethyl ether)
(HCF
2
OCF
2
OCF
2
H);
dimethyl ketone (acetone)
99-40
80-40
IV)
difluoromethoxy
 1-99
10-98
bis(difluoromethyl ether)
(HCF
2
OCF
2
OCF
2
H);
1,1,1,3,3-pentafluorobutane
99-1 
90-2 
(CF
3
CH
2
CF
2
CH
3
, HFC 365 mfc)
V)
difluoromethoxy
 1-40
10-40
bis(difluoromethyl ether)
(HCF
2
OCF
2
OCF
2
H);
1,1,1,4,4,4-hexafluorobutane
99-60
90-60
(CF
3
CH
2
CH
2
CF
3
, HFC 356 ffa)
VI)
difluoromethoxy
 1-96
25-96
bis(difluoromethyl ether)
(HCF
2
OCF
2
OCF
2
H);
methoxymethyl methylether
99-14
75-14
VII)
difluoromethoxy
30-99
35-98
bis(difluoromethyl ether)
(HCF
2
OCF
2
OCF
2
H);
n-hexane
70-1 
65-2 
VIII)
1-difluoromethoxy
 1-93
25-93
1,1,2,2-tetrafluoroethyl
difluoromethyl ether
(HCF
2
OCF
2
CF
2
OCF
2
H);
n-pentane
99-7 
75-7 
IX)
1-difluoromethoxy
30-99
50-98
1,1,2,2-tetrafluoroethyl
difluoromethyl ether
(HCF
2
OCF
2
CF
2
OCF
2
H);
dimethyl ketone (acetone)
70-1 
50-2 
X)
1-difluoromethoxy
15-99
25-98
1,1,2,2-tetrafluoroethyl
difluoromethyl ether
(HCF
2
OCF
2
CF
2
OCF
2
H);
n-hexane
85-1 
75-2 
XI)
1-difluoromethoxy
 5-99
10-98
1,1,2,2-tetrafluoroethyl
difluoromethyl ether
(HCF
2
OCF
2
CF
2
OCF
2
H);
ethyl alcohol
95-1
90-2 
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:
Compositions
are defined within
+/−2% by weight
A)
difluoromethoxy-bis(difluoromethyl ether)
62% by wt.
(HCF
2
OCF
2
OCF
2
H);
n-pentane
38% by wt.
B)
difluoromethoxy-bis(difluoromethyl ether)
63% by wt.
(HCF
2
OCF
2
OCF
2
H);
iso-pentane
36% by wt.
C)
difluoromethoxy-bis(difluoromethyl ether)
42% by wt.
(HCF
2
OCF
2
OCF
2
H);
dimethyl ketone (acetone)
58% by wt.
D)
difluoromethoxy-bis(difluoromethyl ether)
60% by wt.
(HCF
2
OCF
2
OCF
2
H);
1,1,1,3,3 -pentafluorobutane
40% by wt.
(CF
3
CH
2
CF
2
CH
3
, HFC 365 mfc)
E)
difluoromethoxy-bis(difluoromethyl ether)
20% by wt.
(HCF
2
OCF
2
OCF
2
H);
1,1,1,4,4,4-hexafluorobutane
80% by wt.
(CF
3
CH
2
CH
2
CF
3
, HFC 356 ffa)
F)
difluoromethoxy-bis(difluoromethyl ether)
59% by wt.
(HCF
2
OCF
2
OCF
2
H);
methoxymethyl methyl ether
41% by wt.
G)
difluoromethoxy-bis(difluoromethyl ether)
75% by wt.
(HCF
2
OCF
2
OCF
2
H);
n-hexane
25% by wt.
H)
1-difluoromethoxy-1,1,2,2-tetrafluoroethyl
61% by wt.
difluoromethyl ether
(HCF
2
OCF
2
CF
2
OCF
2
H);
n-pentane
39% by wt.
I)
1-difluoromethoxy-1,1,2,2-tetrafluoroethyl
79% by wt.
difluoromethyl ether
(HCF
2
OCF
2
CF
2
OCF
2
H);
dimethyl ketone (acetone)
21% by wt.
L)
1-difluoromethoxy-1,1,2,2-tetrafluoroethyl
74% by wt.
difluoromethyl ether
(HCF
2
OCF
2
CF
2
OCF
2
H);
n-hexane
26% by wt.
M)
1-difluoromethoxy-1,1,2,2-tetrafluoroethyl
95% by wt.
difluoromethyl ether
(HCF
2
OCF
2
CF
2
OCF
2
H);
ethyl alcohol
 5% by wt.
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.
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.
Furthermore, when the non azeotropic or non near-azeotropic compositions contain more volatile flammable components, the vapour phase becomes ri

Affiliated with

Also associated with

Rating

Foaming compositions does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Foaming compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Foaming compositions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3338703