Refrigerant composition

• US 7,560,045 B2
• Filed: 08/25/2006
• Issued: 07/14/2009
• Est. Priority Date: 10/21/2003
• Status: Expired due to Fees

• Current Assignee: Dow Global Technologies, Inc. (Dow, Inc.)
• Original Assignee: Dow Global Technologies, Inc. (Dow, Inc.)
• Inventors: Redwine, Oscar David, Brown, William, Serrano, Myrna
• Primary Examiner(s): Hardee; John R
• Application Number:
  US11/467,371
• Publication Number:
  US 20070040147A1
• Time in Patent Office: 1,054 Days
• Field of Search: 252/68
• US Class Current: 252/68
• CPC Class Codes: C09K 2205/24 Only one single fluoro component present
• CPC Class Codes: C09K 5/045 containing only fluorine as halogen
• CPC Class Codes: C10M 129/74 of polyhydroxy compounds
• CPC Class Codes: C10M 145/26 Polyoxyalkylenes
• CPC Class Codes: C10M 145/36 etherified
• CPC Class Codes: C10M 171/008 Lubricant compositions compatible with refrigerants
• CPC Class Codes: C10M 2207/2835 used as base material
• CPC Class Codes: C10M 2209/1033 used as base material
• CPC Class Codes: C10M 2209/1085 used as base material
• CPC Class Codes: C10M 2209/1095 used as base material
• CPC Class Codes: C10N 2020/101 Containing Hydrofluorocarbons
• CPC Class Codes: C10N 2030/02 Pour-point; Viscosity index
• CPC Class Codes: C10N 2030/12 Inhibition of corrosion, e.g. anti-rust agents or anti-corrosives
• CPC Class Codes: C10N 2030/64 Environmental friendly compositions
• CPC Class Codes: C10N 2040/30 Refrigerators lubricants or compressors lubricants
• CPC Class Codes: F25B 2400/18 Refrigerant conversion

Abstract

This invention describes a new refrigerant/lubricant combination for use in stationary and mobile refrigeration and air conditioning applications. In these applications, the refrigerant and lubricant must be soluble in each other (e.g., miscible) to ensure adequate lubricant circulation from the compressor, through the condenser, expansion device, and evaporator, and back to the compressor. Insufficient lubricant circulation will result in compressor failure. Low temperature solubility is particularly important to ensure lubricant flow through the cold evaporator. In addition, the lubricant and refrigerant combination should be stable in the presence of steel, and aluminum and copper containing metals. This invention describes the combination of refrigerant difluoroethane (e.g. R-152a) and polar, oxygenated lubricants, particular polyalkylene glycols (PAGs) and polyolesters (POEs) which may be used as a replacement for R-134a.

Claims

1. A refrigerant composition comprising:

a. a refrigerant consisting essentially of 1,1-difluoroethane;

b. lubricant consisting of one or more propylene oxide homopolymers selected from the group consisting of polyalkylene glycols (PAG) having the formula

Z-[(—

CH₂—

CH(CH₃)—

O—

)_n—

R]_p

where Z is the residue of a compound having 1-8 active hydrogens,

n is a number having an average value which will give the PAG with a number average molecular weight range from about 1000 to about 4000,

R is H or an alkyl group of 1 to 6 carbon atoms, and

p is an integer having a value equal to the number of active hydrogens of Z; and

c. a flame retardant selected from the group consisting of trifluorochloromethane, trifluoroiodomethane, phosphorous compounds, phosphate esters, hydrocarbons that contain iodine or bromine, hydrofluorocarbons that contain iodine or bromine, fluorocarbons that contain iodine or bromine, or any combination thereof;

wherein the viscosity of the lubricant is between about 40 and 150 cSt at 40°

C. and the lubricant is miscible in the refrigerant between about −

40°

C. and about 40°

C.

2. The refrigerant composition of claim 1 wherein the flame retardant includes a gaseous phase flame retardant.

3. The refrigerant composition of claim 1 wherein flame retardant consists of the phosphorous compounds, the phosphate esters, or both.

4. The refrigerant composition of claim 3 wherein the lubricant consists of the propylene oxide homopolymers and the composition further comprises an additives package consisting of an extreme pressure additive, an anti-wear additive, an antioxidant, a high-temperature stabilizer, a corrosion inhibitor, a detergent, an anti-foaming agent, or any combination thereof.

5. The refrigerant composition of claim 3 wherein at least a portion of the homopolymer PAG is a polymer of propylene oxide (PO) prepared from propylene oxide initiated with a monohydric alcohol.

6. The refrigerant composition of claim 5 wherein the monohydric alcohol includes methanol.

7. The refrigerant composition of claim 5 wherein the monohydric alcohol includes butanol.

8. The refrigerant composition of claim 3, wherein at least a portion of the homopolymer PAG is a polymer of propylene oxide (PO) prepared from propylene oxide initiated with a polyhydric alcohol.

9. The refrigerant composition of claim 3, wherein the composition is a single phase at ambient temperature after 2 weeks in the presence of at least one metal catalyst at an elevated temperature up to 175°

C.

10. The refrigerant composition of claim 3, wherein the composition is clear at ambient temperature after 2 weeks of storage at 175°

C. in the presence of at least one metal selected from the group consisting of steel, aluminum, copper and combinations thereof.

11. The refrigerant composition of claim 10 wherein the lubricant is present at a concentration between 3 and 30 wt.%.

12. The refrigerant composition of claim 1 wherein the flame retardant consists of trifluorochloromethane, trifluoroiodomethane, phosphorous compounds, phosphate esters, hydrocarbons that contain iodine or bromine, hydrofluorocarbons that contain iodine or bromine, fluorocarbons that contain iodine or bromine, or any combination thereof.

13. The refrigerant composition of claim 12 wherein the flame retardant consists of trifluorochloromethane, trifluoroiodomethane, hydrocarbons that contain iodine or bromine, hydrofluorocarbons that contain iodine or bromine, fluorocarbons that contain iodine or bromine, or any combination thereof.

14. The refrigerant composition of claim 1 wherein

at least a portion of the homopolymers pag is a polymer of propylene oxide (PO) prepared from propylene oxide initiated with a monohydric alcohol;

the lubricant is present at a concentration between 3 and 30 wt.%; and

the composition is clear at ambient temperature after 2 weeks of storage at 175°

C. in the presence of at least one metal selected from the group consisting of steel, aluminum, copper and combinations thereof.

15. The refrigerant composition of claim 14 wherein the flame retardant includes the phosphate ester.

16. The refrigerant composition of claim 15 wherein the the flame retardant consists of the phosphate ester.

17. The refrigerant composition of claim 15 wherein the monohydric alcohol includes butanol.

18. The refrigerant composition of claim 1 wherein the flame retardant consists of the phosphate esters.

19. A refrigerant composition comprising:

a. a hydrofluorocarbon refrigerant having a global warming potential lower than that of R-134a;

b. lubricant consisting of one or more propylene oxide homopolymers selected from the group consisting of polyalkylene glycols (PAG) having which has the formula

Z-[(—

CH₂—

CH(CH₃)—

O—

)<sub>n—

R]p</sub>

where Z is the residue of a compound having 1-8 active hydrogens,

n is a number having an average value which will give the PAG with a number average molecular weight range from about 1000 to about 4000,

R is H or an alkyl group of 1 to 6 carbon atoms, and

p is an integer having a value equal to the number of active hydrogens of Z; and

c. an additives package consisting of an extreme pressure additive, an anti-wear additive, an antioxidant, a high-temperature stabilizer, a corrosion inhibitor, a detergent, an anti-foaming agent, a flame retardant, or any combination thereof;

wherein the additives package includes the flame retardant, and the flame retardant consists of trifluorochloromethane, trifluoroiodomethane, phosphorous compounds, phosphate esters, hydrocarbons that contain iodine or bromine, hydrofluorocarbons that contain iodine or bromine, fluorocarbons that contain iodine or bromine, or any combination thereof.

20. The refrigerant composition of claim 19 wherein the flame retardant consists of the phosphate esters.