ES2270978T3 - REFRIGERANT LUBRICANT COMPOSITIONS THAT INCLUDE A FOAM INDUCTIVE ADDITIVE. - Google Patents

Abstract

A lubricant composition has a synthetic lubricant base oil, preferably a polyol ester, and a polyether foam-inducing additive. The composition is suitable for use in a refrigerant system, particularly with HFC refrigerant gases. The foam-inducing additive is an alternative to known silicon-containing foam-inducing additives, which are not suitable for all refrigerant systems.

Description

Cooling lubricant compositions that They comprise a foam inducing additive.

This invention relates to a composition. lubricant and its use in refrigeration systems.

It is known that excessive foaming in the Cooling systems is not desirable. Reduce the effectiveness of the lubricant composition when cooling the motor bovines and Remove heat from the compressor. In addition, too much foam can make too much lubricant composition passes through the mouth of the system and enter the low pressure zone of the system refrigeration. However, a moderate amount of foaming it can be beneficial, particularly for noise suppression inside the refrigeration system compressor. Section 7.20 from the 1998 ASHRAE Refrigeration Handbook indicates that "one layer foamy on top of the level of the lubricant dampens the noise created by the moving parts of the compressor. "There are other benefits of foaming; for example the control of the vapor release rate as described in WO / 9512649 and promotion of enhanced oil return as described in US 4829786.

Historically, mineral oils were used in lubricating compositions for refrigerant gases chlorofluorocarbons (CFC) and hydrochlorofluorocarbons (HCFC). These mixtures of lubricating composition / CFC / HCFC demonstrated a tendency to foam. In some cases where foaming does not it is desirable or excessive it was found that it was necessary to control foam production In other cases, in which the foaming is advantageously, it was found that it was necessary to promote foaming. For example, US 3,792,755 describes a method for attenuating noise produced by a hermetic compressor unit in operation that has means to stir the lubricant composition during operation, lubricant composition containing a foaming agent, which is an organosiloxane. The foaming agent helps generate and keep a cachaza or fine bubble foam that acts to absorb and thus attenuate the noise produced by the compressor unit during operation CFCs described in US 3,792,755 include dichloroethylene, dichlorodifluoromethane (R-12) and monochlorodifluoromethane (R-22).

In recent years, legislation has dictated a departure from such traditional refrigerant gases towards alternatives that have lower ozone depletion potential or zero, such as hydrofluorocarbon gases (HFC). This change in the refrigerant gas has needed a change in the composition lubricant away from mineral oils, which are not compatible with these new HFC gases. Lubricating compositions are used Synthetic compatible with more polar HFCs. Examples of fluids basic suitable for such synthetic lubricant compositions they are polyalkylene glycols, polyol esters, polyvinyl ethers and alkylbenzenes.

It has been found that gas mixtures HFC refrigerants and such synthetic lubricant compositions tend to show a tendency to foaming inherently very lower than CFC blends with lubricating compositions based on mineral oils. For example, see Chapter 5 of "Foaming Characteristics of Refrigerant / Lubricant Mixtures", reference number DOE / CE / 23810-88a, which presented the work supported by the Department of Energy of USA and was prepared by The Air-Conditioning and Refrigeration Technology Institute in March 1998. By consequently, when foam generation is an advantage, there is a need to generate a cachaza or foam of fine bubbles in The lubricating composition The generation of such foam can achieved by adding a foaming additive to the lubricating composition

Known foaming additives are based on silicon, for example organosiloxanes or silicones. WO 95/12649 describes a lubricant composition comprising a lubricant of synthetic polyol ether and an additive that increases the density of the foam to use in a refrigerator system with at least one compressor and a halocarbon refrigerant gas, preferably a HFC The additive that increases foam density is preferably a siloxane but it can also be a polymer ester halogenated aliphatic (for example, Fluorad FC430 available from 3M) and it is found that both increase the density of the foam and control the release of steam from the compressor.

EP 0590238 A1 describes a compressor for compress an HFC refrigerant that is characterized by the presence  of a lubricating composition consisting of an ester of pentaerythritol and a siloxane foaming additive where creates a layer of oil foam during operation of the compressor to reduce compressor noise.

JP10088173 A2 describes lubricating compositions for refrigeration compressors for noise reduction, which comprise HFC refrigerants, sterile oily lubricants with at least 2 ester bonds, a hydrolytic stabilizer, a antioxidant and 0.001-0.01% by weight of oils Silicones

However, these foaming additives that contain silicon may not be suitable for all systems refrigerants since they are only partially miscible with the oil base of the lubricant composition. This can lead to separation of additives containing silicone in the parts Cooling system cooling. The loss of additives that contain silicone can also cause loss of foaming due to the depletion of additive, the fouling of surfaces of heat exchangers and blocking of valves On the other hand, the silicones present on surfaces metallic prevent the painting of such surfaces.

Hence they are looking for foaming additives Alternative

According to this, in a first aspect, the The present invention provides a lubricating composition that understands:

to)

a synthetic lubricant base oil; Y

b)

a foam inducing additive, comprising a polyether having the formula

X-O- (RO) n -Y

in the that

-O- (RO) n - is a main chain of polyether

R is a group partially or fully halogenated alkyl having 1 to 10 carbon atoms and in which adjacent R groups can be same or different

n is in the range from 1 to 1000 and

X and Y are groups terminals, as indicated in claim 1.

By partially halogenated, it is understood that at minus one hydrogen atom of the alkyl group has been replaced by a halogen atom. Preferably, at least one atom of hydrogen in each of the carbon atoms of the alkyl group is has replaced by a halogen atom, more preferably all the hydrogen atoms of the alkyl group have been replaced by halogen atoms, so that R is a fully alkyl group halogenated Preferably, the halogen atom is an atom of fluorine. It is especially preferred when fluorine atoms have replaced all the hydrogen atoms in the group I rent.

The alkyl group, R, can be branched or of linear chain and can be saturated or unsaturated. R has preferably from 1 to 7 carbon atoms, more preferably from 1 to 4 carbon atoms. Examples of preferred R include -CF 2 -, -CF 2 CF 2 -, -CF (CF 3) -, -CF (CF 3) CF 2 -, -CF 2 CF 2 CF 2 - and -CF 2 CF 2 CF 2 CF 2 -. R can be chosen so that the polyether be a block, random or graft copolymer or a homopolymer

n is preferably in the range of 1 to 100, more preferably from 1 to 50. n may be the same or different for R. groups

An example of a preferred embodiment is

X-O- (R 1 O) n 1 - (R 2 O) n 2 -Y

where R1 and R2 are as defined for R but R 1 is different from R 2. n1 and n2 can be the same or different.

The main polyether chain has two groups terminals, X and Y. At least one of the groups X and Y terminals It comprises at least one functionalized group. Types of groups Functionalized include hydroxyl, ester, ethoxylated hydroxyl, ethoxylated ester, both organic and inorganic, amine, cyano and amide. The or each functionalized group may be located in the terminal group so that it connects directly to the chain polyether main; may be located at the tip of the terminal group away from the main polyester chain; or can be located within the main chain of the terminal group. Preferably, the functionalized group is located in the end of the terminal group away from the main chain of polyether Other groups that may be present within or from each terminal group includes alkyl and haloalkyl, in particular fluoroalkyl. Preferably, the terminal group is such that confers solubility of the foam inducing agent in the oil of synthetic lubricant base. Examples of terminal groups, which they comprise a functionalized group, they are -CF2COOCH3, -CF 2 CH 2 OH, -CF 2 CH 2 O (CH 2 CH 2 O) n H and -CF 2 CH 2 OCH 2 CH (OH) CH 2 OH.

The foam inducing additive has preferably a molecular weight between 100 and 10,000 units atomic, more preferably between 200 and 5000 atomic units. It is present at a level of between 0.0001 and 1.0% by weight in the lubricant composition, preferably at a level of between 0.0001 and 0.05%

The synthetic lubricant base oil is select so that the lubricant composition is compatible with HFC refrigerant gases. Preferably, it is selected from alkylbenzenes, polyvinyl ethers, polyalkylene glycols and esters Preferably, the synthetic lubricant base oil is an ester, more preferably an ester that is a derivative of a polyol, preferably a hydrocarbon-based polyol aliphatic, which has 2 to 6 hydroxyl groups and, preferably, from 3 to 12 carbon atoms. Suitable polyols include neopentyl glycol, pentaerythritol, trimethylolpropane, ditrimethylolpropane and dipentaerythritol. The ester is derived from the reaction of such polyol with one or more monocarboxylic acids saturated or unsaturated, linear or branched, having 3 to 12 carbon atoms, and optionally one or more acids saturated or unsaturated, linear or branched polycarboxyls, which have 4 to 54 carbon atoms. Preferably, the acids polycarboxylic acids, if present, have 2 or 3 groups carboxyl All the above acids can be replaced by their esterifiable derivatives, for example anhydrides.

Examples of suitable lubricant compositions include the EMKARATE RL range of cooling lubricants available from Uniqema, a company of Chemical Industries plc. The synthetic lubricant base oils for these lubricant compositions are derived from pentaerythritol or oligomers thereof and / or neopentyl glycol which are reacted with linear and / or branched acids (or their esterifiable derivatives) having 5 to 10 atoms of
carbon.

The synthetic lubricant base oil has a viscosity at 40 ° C from 2 to 500 cSt.

The lubricating composition has a viscosity at 40ºC from 2 to 500 cSt. The lubricating composition may comprise in addition other foaming additives, for example organosiloxanes or silicones If present, such other foaming additives are at a level of between 0.0001 and 1.0% by weight in the composition lubricant, preferably at a level between 0.0001 and 0.1%, plus preferably at a level between 0.0001 and 0.05%. The composition lubricant can also comprise other lubricant additives functional. Suitable additives include antioxidants, additives antiwear, agents for extreme pressures, eliminators of acids, stabilizers, surfactants, index improvers viscosity, corrosion inhibitors, deactivators or metal passivators, lubricity enhancers or agents of oiliness and modifiers against friction.

In a second aspect, the present invention provides the use of a lubricating composition in a system of refrigeration, wherein the lubricant composition comprises

to)

a synthetic lubricant base oil; Y

b)

a foam inducing additive, comprising a polyether having the formula

X-O- (RO) n -Y

in the that

-O- (RO) n - is a main chain of polyether

R is a group partially or fully halogenated alkyl having 1 to 10 carbon atoms and in which adjacent R groups can be same or different

n is in the range from 1 to 1000 and

X and Y are groups terminals, as indicated in claim 10.

The refrigerant of the refrigerant system suitably comprises a hydrochlorofluorocarbon (HCFC), an HFC or a combination of refrigerants containing at least one HFC, HCFC or both. Preferably, the refrigerant does not contain atoms of chlorine. Suitable HFC gases include R134a (1,1,1,2-tetrafluoroethane), R-32 (difluoromethane), R-125 (1,1,1,2,2-pentafluoroethane), R-152a (1,1-difluoroethane) and R-143a (1,1,1-trifluoroethane). There may be others components in the combination of refrigerants, for example hydrocarbons, preferably with 1 to 6 carbon atoms, fluorinated hydrocarbons and other refrigerants, for example dioxide of carbon or ammonia.

The present invention is further illustrated by reference to the following non-limiting examples.

Example one

The foaming tendency and the stability of the 200 ml foam of a lubricating composition comprising EMKARATE RL 22H from ICI and various levels of foam inducing additive, Fomblin HC-OH from Ausimont (HOCH2 CF2O- ( CF 2 CF 2 O) p - (CF 2 O) q -CF 2 CH 2 OH), were measured at room temperature (24.5 ° C). The foaming tendency of the lubricant composition was determined using the standard test method ASTM D-892-97, Standard Test Method for Foaming Characteristics of Lubricating Oils. The test determines the tendency of the foam in terms of the volume of foam produced by bubbling air through 200 ml of the lubricating composition. Foam stability is the time elapsed in seconds for the foam
disappear

The results are shown in Table 1.

Example 2

Example 1 was repeated, except that it bubbled R134a through the lubricant composition instead of air. The Results are shown in Table 2.

Example 3

Example 1 was repeated, except that Fomblin HC-OH was replaced by Fluorolink E10 (H (OCH 2 CH 2) n OCH 2 CF 2
O- (CF 2 CF 2 O) p - (CF 2 O) q -CF 2 CH 2 O (CH 2 CH 2 O) n H) of Ausimont. The results are shown in Table 3.

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TABLE 1

Concentration from Trend Stability from Fomblin HC-OH (ppm) the Foam (ml) the foam (seconds) 0 0 0 twenty twenty 0 fifty 380 135 100 380 219 250 400 206 500 370 220

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TABLE 2

Concentration from Trend Stability from Fomblin HC-OH (ppm) the Foam (ml) the foam (seconds) 0 0 0 twenty 0 0 fifty 40 35 100 30 27 250 twenty 10 500 30 19

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TABLE 3

Concentration from Trend Stability from Fomblin HC-OH (ppm) the Foam (ml) the foam (seconds) 0 0 0 250 390 194

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Example 4

The foaming tendency and the stability of the 200 ml foam of a lubricating composition comprising various qualities of EMKARATE RL of ICI and 250 ppm of additive Fomblin HC-OH foam inducer were measured at ambient temperature (24.5ºC) bubbling through so much air as R134a. The results are shown in Table 4.

TABLE 4

Quality of Trend the Foam Trend Stability of the Foam Foam Stability EMKARATE RL Foam in Air (ml) in R134a (ml) in air (seconds) in R134a (seconds) 32H 480 fifty 294 58 15H 230 fifty 112 twenty-one 7H fifty 30 twenty-one 12

Example 5

The foaming tendency and the stability of the 200 ml foam of a lubricating composition comprising EMKARATE RL 22H from ICI and various foam inducing additives They were measured at room temperature (24.5 ° C). The results are shown in Table 5.

TABLE 5

Foam Inductive Additive Trend Air Foam Foam Stability in Air (ppm) (ml) (seconds) Fomblin HC-OH (250 ppm) 470 237 Fluorolink E10 (250 ppm) 390 194 Fluorad FC430 (250 ppm) 0 0 (Comparative) FS1265 (250 ppm) (Comparative) 360 222 Fomblin and Lvac (250 ppm) 0 0 (Comparative) PDMS 1 (500 ppm) (Comparative) 5 13 PDMS 2 (500 ppm) (Comparative) 5 30 FS1265 is trifluoromethylsiloxane of Dow. Fomblin and Lvac it is a perfluoroalkyl ether of molecular weight approximately 2400 from Ausimont. PDMS 1 is Silicone Fluid SWS-101 50 from Akrochem's viscosity 50 cSt. PDMS 2 is Silicone Fluid SWS-101 Akrochem 350 viscosity 350 cSt. Fluorad FC430 is a surfactant 3M fluorinated.

The results are indicative of a trend and superior foam stability of the compositions lubricants of the present invention.

Example 6

Example 1 was repeated using 250 ppm of Fomblin HC-OH and the addition of 120 ppm Silicone Fluid SWS-101 50 of Akrochem of 50 cSt. The Results are shown in Table 6.

TABLE 6

Foam Inductive Additive Trend Air Foam Foam Stability in Air (ppm) (ml) (seconds) Fomblin HC-OH (250 ppm) Y 350 178 Silicone (120 ppm) Silicone only (120 ppm) - Comparative 150 78

Claims (10)

1. A lubricating composition comprising:

to)

a synthetic lubricant base oil; Y

b)

a foam inducing additive, comprising a polyether having the formula

         \ vskip1.000000 \ baselineskip
      

X-O- (RO) n -Y

         \ vskip1.000000 \ baselineskip
      

in the that

-O- (RO) n - is a main chain of polyether

R is a group partially or fully halogenated alkyl having 1 to 10 carbon atoms and in which adjacent R groups can be same or different

n is in the range from 1 to 1000 and

X and Y are groups terminals, where at least one of the terminal groups X and Y It comprises at least one functionalized group selected from hydroxyl, ester, ethoxylated hydroxyl, ethoxylated ester, both Organic as inorganic, amine, cyano and amide.

2. A lubricating composition according to the claim 1, wherein R is a fully alkyl group halogenated having 1 to 7 carbon atoms. 3. A lubricating composition according to the claim 1 or claim 2, wherein the halogen is fluorine. 4. A lubricating composition according to a any one of claims 1 to 3, wherein n is in the range from 1 to 100. 5. A lubricating composition according to any one of claims 1 to 4, wherein the at least one functionalized group is located at the end of the terminal group away from the main chain of
polyether 6. A lubricating composition according to a any one of claims 1 to 5, wherein the at least one functionalized group includes haloalkyl groups. 7. A lubricating composition according to a any one of claims 1 to 6, wherein the additive foam inductor is present at a level between 0.0001 and 0.1% by weight of the lubricant composition. 8. A lubricating composition according to a any one of claims 1 to 7, wherein the oil of Synthetic lubricant base is chosen from alkylbenzenes, poly (ethers vinyl), polyalkylene glycols and esters. 9. A lubricating composition according to the claim 8, wherein the synthetic lubricating base oil It is an ester that is a derivative of a polyol. 10. Use of a lubricating composition in a cooling system, in which the lubricant composition understands

to)

a synthetic lubricant base oil; Y

b)

a foam inducing additive, comprising a polyether having the formula

         \ vskip1.000000 \ baselineskip
      

X-O- (RO) n -Y

         \ vskip1.000000 \ baselineskip
      

in the that

-O- (RO) n - is a main chain of polyether

         \ newpage
      

R is a group partially or fully halogenated alkyl having 1 to 10 carbon atoms and in which adjacent R groups can be same or different

n is in the range from 1 to 1000 and

X and Y are groups terminals, where at least one of the terminal groups X and Y It comprises at least one functionalized group selected from hydroxyl, ester, ethoxylated hydroxyl, ethoxylated ester, both Organic as inorganic, amine, cyano and amide.