U.S. patent application number 17/533460 was filed with the patent office on 2022-03-17 for use of semi-aromatic copolyamide for transporting refrigerant fluid.
This patent application is currently assigned to Arkema France. The applicant listed for this patent is Arkema France. Invention is credited to Philippe Blondel, Beno t Brule, Eric Gamache, Estelle Meurice Pierrat.
Application Number | 20220082186 17/533460 |
Document ID | / |
Family ID | |
Filed Date | 2022-03-17 |
United States Patent
Application |
20220082186 |
Kind Code |
A1 |
Blondel; Philippe ; et
al. |
March 17, 2022 |
USE OF SEMI-AROMATIC COPOLYAMIDE FOR TRANSPORTING REFRIGERANT
FLUID
Abstract
Provided is a method for heating or cooling a liquid or a body
by means of a vapor compression circuit containing a heat transfer
fluid. The vapor compression circuit element includes at least one
layer that includes copolyamide of formula X/10.T/Y, where the
structural variables are described herein.
Inventors: |
Blondel; Philippe; (Bernay,
FR) ; Brule; Beno t; (Beaumont-Le-Roger, FR) ;
Gamache; Eric; (Philadelphia, PA) ; Meurice Pierrat;
Estelle; (Corneville sur-Risle, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Arkema France |
Colombes |
|
FR |
|
|
Assignee: |
Arkema France
Colombes
FR
|
Appl. No.: |
17/533460 |
Filed: |
November 23, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16784323 |
Feb 7, 2020 |
11209105 |
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17533460 |
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16276160 |
Feb 14, 2019 |
10914409 |
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16784323 |
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14767530 |
Aug 12, 2015 |
10605385 |
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PCT/FR2014/050290 |
Feb 13, 2014 |
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16276160 |
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International
Class: |
F16L 11/08 20060101
F16L011/08; B29C 48/00 20060101 B29C048/00; C09K 5/04 20060101
C09K005/04; C08G 69/36 20060101 C08G069/36; C08G 69/26 20060101
C08G069/26; B32B 25/14 20060101 B32B025/14; B32B 27/34 20060101
B32B027/34; C08L 77/06 20060101 C08L077/06; B32B 27/32 20060101
B32B027/32; C08L 77/02 20060101 C08L077/02; B32B 1/08 20060101
B32B001/08; B32B 25/10 20060101 B32B025/10; B32B 27/20 20060101
B32B027/20; B32B 27/22 20060101 B32B027/22; B32B 25/08 20060101
B32B025/08; C08L 101/00 20060101 C08L101/00; B29C 45/00 20060101
B29C045/00; B29C 49/00 20060101 B29C049/00; F25B 13/00 20060101
F25B013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 18, 2013 |
FR |
13.51361 |
Claims
1.-28. (canceled)
29. A heat transfer device comprising a vapor compression circuit
which comprises at least one vapor compression circuit element
comprising at least one layer consisting of (1) 30% to 99% by mass
of at least one copolyamide comprising units of the formula X, 10.T
and Y and (2) at least one member selected from the group
consisting of functionalized polyolefins, plasticizers, conversion
aids, fillers, heat stabilizers, UV stabilizers, nucleating agents,
dyes, pigments, mold release agents, flame retardants, surfactants,
fluorescent whiteners, additional polymers, and antioxidants,
wherein: X represents alternatively the residues of an aliphatic
amino acid comprising from 8 to 18 carbon atoms, or a lactam, or
the unit X.sub.1.X.sub.2 which represents the residues resulting
from the condensation of an aliphatic diamine comprising from 6 to
18 carbon atoms and a (cyclo)aliphatic dicarboxylic acid comprising
from 6 to 18 carbon atoms; 10.T represents the residues from the
condensation of a decane diamine and terephthalic acid; Y
represents the residues from the condensation of an aliphatic
diamine comprising from 9 to 14 carbon atoms and an aromatic
dicarboxylic acid, Y being different from the unit 10.T; the molar
proportion of units 10.T in the copolyamide is greater than 0%; the
molar proportion of the units Y relative to the total of units 10.T
and Y is from 0% to 30%; the proportion of units X is from 0.4 to
0.8 mol per mole of semi-aromatic units 10.T and Y; the vapor
compression circuit element is suitable for transporting a heat
transfer fluid selected from the group consisting of hydrocarbon,
hydrofluorocarbon, ether, hydrofluoroether, and fluoroolefin
compounds; and the heat transfer device is selected from the group
consisting of mobile and stationary air conditioning devices,
refrigeration devices, freezing devices, Rankine-cycle and
heat-pump heating devices.
30. The heat transfer device as claimed in claim 29, wherein the
vapor compression circuit contains a heat transfer fluid selected
from the group consisting of hydrocarbon, hydrofluorocarbon, ether,
hydrofluoroether, and fluoroolefin compounds.
31. The heat transfer device as claimed in claim 30, wherein the
heat transfer fluid is admixed with a lubricant.
32. The heat transfer device as claimed in claim 29, wherein the
vapor compression circuit element is in contact with the heat
transfer fluid and wherein the heat transfer fluid is a admixed
with a lubricant.
33. The heat transfer device as claimed in claim 29, wherein the
vapor compression circuit element belongs to a vapor compression
circuit integrated in a device selected from the group consisting
of mobile and stationary air conditioning devices, refrigeration
devices, freezing devices, Rankine-cycle and heat-pump heating
devices.
34. The heat transfer device as claimed in claim 29, wherein the
vapor compression circuit element is a connection element or a
pipe.
35. The heat transfer device as claimed in claim 29, wherein said
layer is disposed on an inner surface of the element.
36. A heat transfer device as claimed in claim 29, wherein the
vapor compression circuit element is a multilayer tube comprising
in succession: an inner layer consisting of the at least one
copolyamide; optionally, a first intermediate layer, composed of a
first composition comprising an elastomeric material; optionally, a
second intermediate layer, composed of a reinforcing textile; and
an outer layer, composed of a second composition comprising an
elastomeric material.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a Divisional of U.S. application
Ser. No. 16/784,323, filed Feb. 7, 2020, which is a Divisional of
U.S. application Ser. No. 16/276,160, filed Feb. 14, 2019, now U.S.
Pat. No. 10,914,409, which is a Divisional of U.S. application Ser.
No. 14/767,530, filed Aug. 12, 2015, now U.S. Pat. No. 10,605,385,
which is a national phase application of International Application
No. PCT/FR2014/050290, filed Feb. 13, 2014, which claims priority
to French Application No. 13.51361, filed Feb. 18, 2013. The
disclosures of each of these applications are incorporated herein
by reference in their entireties for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates to the use of a composition
based on semi-aromatic copolyamide for producing circuit elements
intended for transporting a refrigerant fluid (such as R-1234yf),
especially in the field of motor vehicle air conditioning.
BACKGROUND OF THE INVENTION
[0003] The transporting of refrigerant fluids in vapor compression
circuits, such as those employed more particularly in motor vehicle
air conditioning, necessitates the use of materials having a very
specific set of mechanical, thermal, and chemical properties.
[0004] The elements in these circuits (and especially the tubing)
are required in particular: [0005] to be impervious to the fluids
being transported (and in particular to fluorocarbon refrigerant
compounds), and also to water and to oxygen; [0006] to exhibit
chemical resistance to the fluids being transported, and also to
water and to oxygen, in order to prevent excessive degradation over
the long term; [0007] to exhibit sufficient mechanical resistance
but also sufficient flexibility (especially in motor vehicle air
conditioning, where the under-hood assembly and congestion
constraints dictate folding of the tubing); [0008] to exhibit
satisfactory heat resistance, owing to the fact that the fluids
being transported may be at a high temperature, and that the
temperature of the environment may also be high (especially in
motor vehicle air conditioning, since the components in question
may be positioned close to the engine).
[0009] The above constraints are particularly difficult to observe
with certain refrigerant fluids. For example, the fluid R-1234yf
(2,3,3,3-tetrafluoropropene), which can be used more particularly
in motor vehicle air conditioning, is more chemically reactive than
the fluids of the preceding generation, such as R-134a
(1,1,1,2-tetrafluoroethane). The chemical resistance and the
barrier properties of the elements in the vapor compression
circuits are therefore even more critical. The difficulty of
observing the constraints above is exacerbated by the fact that
certain lubricants, when used in a mixture with refrigerant
compounds (such as polyalkylene glycols or PAGs), also have a
tendency to be aggressive with respect to these circuit
elements.
[0010] At the present time, the tubing for transporting refrigerant
fluids in motor vehicle air conditioning comprises rigid metallic
portions (generally made of aluminum) and flexible portions made of
multilayer tubes. Some of these multilayer tubes are known as
veneer tubes; they comprise in succession, from the outside to the
inside, a first layer of rubber-type elastomer, a reinforcing
braid, a second layer of rubber-type elastomer, and an inner layer
based on polyamide.
[0011] In the versions available commercially, the inner layer
based on polyamide (or PA) may be, for example, a formulated PA 6
(polycaprolactam) (with or without plasticizer, with or without
impact modifier, with or without stabilizer), a formulated PA 6/6.6
copolyamide (with or without plasticizer, with or without impact
modifier, with or without stabilizer), or else an alloy PA 6 or PA
6.6 (polyhexamethylene adipamide) with polyolefins and
functionalized polyolefins (product sold under the brand name
Orgalloy.RTM. by Arkema).
[0012] Furthermore, document US 2007/0048475 describes a variant of
these multilayer tubes, wherein the inner layer is based on PA 9.T
(polymer of 1,9-nonanediamine or 2-methyl-1,8-ottanediamine and
terephthalic acid), optionally blended with another polyamide
resin.
[0013] Document US 2012/0279605 describes another variant of the
multilayer tubes above, wherein the inner layer is a composition
comprising a polyamide, an impact modifier, a phenolic antioxidant,
a plasticizer, and a copper-based heat stabilizer. The polymer may
be selected from a list of polymers including, in particular, PA
6/6.T (copolymer containing PA 6 segments and PA 6.T segments, in
other words a polymer of hexamethylenediamine and terephthalic
acid). The preferred polyamide, however, is PA 6.
[0014] Document US 2011/0136957 describes a resin for the inner
layer of a vapor compression circuit, the resin being said to be
chemically resistant toward R-1234yf. The resin is selected from a
long list of polymers, including polyamides and more particularly
semi-aromatic polyamides. In the examples, the resins used are
based on PTFE (polytetrafluoroethylene) of polyimide.
[0015] Document US 2011/0183095 describes tubes for transporting
heat transfer fluids in motor vehicle air conditioning, comprising
an inner layer based on PA 6.10 (polyhexamethylene sebacamide) and
an outer layer based on a polyamide such as a polyphthalamide. The
polyphthalamide exemplified is PA 9.T.
[0016] Document US 2011/0239674 describes joints for a vapor
compression circuit, made from the same materials. Document US
2012/0018995 also describes assemblies of tubes and joints that are
made from the same materials. Documents WO 2010/061289 and US
2011/0277492 further describe vapor compression circuit elements
made from these same materials.
[0017] Document US 2011/0155359 relates to tubes for transporting
R-1234yf that are made from a resin based on semi-aromatic
polyamide. The semi-aromatic copolyamide used in the examples is PA
6.6/6.T (copolymer of PA 6.6 and PA 6.T).
[0018] In a more general context, document EP 1505099 describes
compositions intended for replacement of rubbers or metals, or for
use as materials of electrical cables, or for the manufacture of
tanks, hoses, and containers. These compositions comprise
copolyamides of general formula PA X/Y.Ar (Ar meaning aromatic),
including PA 11/10.T, which results from the condensation of
aminoundecanoic acid, 1,10-decanediamine, and terephthalic
acid.
[0019] Document WO 2006/037615 describes compositions based on
semicrystallized polyamides for the manufacture of flexible tubes
for transporting different fluids such as fuels (gasoline or
diesel), hydraulic braking fluid, and others. PA 6.10, PA 6.12, and
PA 10.10 are given as examples.
[0020] Document EP 1717022 relates to multilayer tubes for various
applications, and more particularly for the transport of fuel in
vehicles, from the tank to the engine. These tubes comprise an
intermediate polyamide layer, made for example of PA 6.10
(polyhexamethylene sebacamide) or PA 6.12 (polyhexamethylene
dodecanamide).
[0021] Documents WO 2010/015785 and WO 2010/015786 describe
compositions based on semi-aromatic copolyamide of general formula
A/10.T for the manufacture of various articles, for instance
consumer goods such as electrical, electronic, or automotive
equipment, surgical hardware, packaging, or else sports
articles.
[0022] Similar applications are envisaged in document WO
2011/015790, which relates to compositions based on copolyamide
11/10.T, 12/10.T, etc.
[0023] Document WO 2011/077032 aims to provide a semi-aromatic
polyamide which can be used generally in the manufacture of a
variety of articles, for instance electronic components intended
for electrical or electronic equipment in the field of road
transport, road traffic or rail traffic, in the aeronautical,
audio-video, and videogames fields, and also in the industrial
sector. This semi-aromatic polyamide may be, among others, of
formula 10/10.T, 11/10.T, 12/10.T, etc.
[0024] Document US 2011/0123749 describes a copolyamide
corresponding to the condensation of 1,6-hexanediamine,
1,10-decanediamine, terephthalic acid, and at least one further
monomer selected from the group of dicarboxylic acids comprising
from 8 to 18 carbon atoms, laurolactam, aminolauric acid, and
combinations thereof. The intended uses are as containers and
conduits in the automotive sector, as for example fuel, oil,
coolant, or urea lines.
[0025] None of the above documents describes polymeric material
having properties that are fully satisfactory for the transport of
heat transfer fluid, especially in motor vehicle air conditioning,
and especially when the heat transfer fluid is a hydrofluorocarbon
compound (HFO) such as R-1234yf (mixed with a lubricating oil).
[0026] There is therefore a need for development of vapor
compression circuit elements that display an effective compromise
between their properties of imperviousness to the heat transfer
fluid, to water, and to oxygen, their chemical resistance to the
heat transfer fluid, to water, and to oxygen, their mechanical
strength, their flexibility, and their heat resistance. This need
is felt particularly in the area of motor vehicle air conditioning,
especially when the heat transfer fluid is R-1234yf, admixed with a
lubricant such as a polyalkylene glycol (PAG) or else polyol ester
(POE) oil.
SUMMARY OF THE INVENTION
[0027] The invention concerns first of all a vapor compression
circuit element comprising at least one layer composed of a
composition comprising copolyamide of formula X/10.T/Y, in which:
[0028] X represents alternatively the residues of an aliphatic
amino acid comprising from 8 to 18 carbon atoms, or the unit
X.sub.1.X.sub.2 which represents the residues resulting from the
condensation of an aliphatic diamine comprising from 6 to 18 carbon
atoms and a (cyclo)aliphatic dicarboxylic acid comprising from 6 to
18 carbon atoms; [0029] 10.T represents the residues from the
condensation of a decane diamine and terephthalic acid; and [0030]
Y represents from the condensation of an aliphatic diamine
comprising from 9 to 14 carbon atoms and an aromatic dicarboxylic
acid;
[0031] the molar proportion of units 10.T in the copolyamide being
greater than 0%;
[0032] the molar proportion of the units Y relative to the total of
units 10.T and Y being from 0% to 30%; and
[0033] the proportion of units X being from 0.4 to 0.8 mol per mole
of semi-aromatic units 10.T and Y.
[0034] According to one embodiment, the copolyamide of formula
X/10.T/Y is a copolyamide of formula X/10.T.
[0035] According to one embodiment, X represents either the
residues of an aliphatic amino acid comprising from 10 to 12 carbon
atoms or the unit X.sub.1.X.sub.2 which represents the residues
resulting from the condensation of an aliphatic diamine comprising
from 6 to 12 carbon atoms and an aliphatic diacid comprising from 6
to 12 carbon atoms.
[0036] According to one embodiment, Y represents a unit 10.I, 9.T,
12.T, or 14.T.
[0037] According to one embodiment, the copolyamide of formula
X/10.T/Y is selected from the copolyamides of formulae 11/10.T,
12/10.T, 6.10/10.T, 6.12/10.T, 10.6/10.T, 10.10/10.T, 10.12/10.T,
12.12/10.T, and 10.14/10.T, and more preferably is a copolyamide of
formula 11/10.T.
[0038] According to one embodiment, the proportion of units X in
the copolyamide is from 0.5 to 0.7 mol per mole of semi-aromatic
units 10.T and Y.
[0039] According to one embodiment, the copolyamide X/10.T/Y is
present in the composition in a proportion by mass of 30% to 99%,
preferably of 40% to 95%, more preferably of 50% to 85%; and/or the
composition further comprises: [0040] optionally, one or more
functionalized or non-functionalized polyolefins, preferably in a
proportion by mass of 5% to 40%, more preferably of 12% to 36%;
[0041] optionally, one or more plasticizers, preferably in a
proportion by mass of 1% to 10%, more preferably of 2% to 7%;
[0042] optionally, one or more additives selected from conversion
aids, fillers, heat stabilizers, UV stabilizers, nucleating agents,
dyes, pigments, mold release agents, flame retardants, surfactants,
fluorescent whiteners, antioxidants, and mixtures thereof.
[0043] According to one embodiment, the vapor compression circuit
element is suitable for transporting a heat transfer fluid, said
heat transfer fluid being preferably selected from hydrocarbon,
hydrofluorocarbon (HFO), ether, hydrofluoroether, or fluoroolefin
compounds, more particularly from fluoropropenes, fluoropropanes,
and fluoroethanes; and more preferably from
1,3,3,3-tetrafluoropropene, 2,3,3,3-tetrafluoropropene,
1,2,3,3,3-pentafluoropropene, 1,1,3,3-tetrafluoropropene,
3,3,3-trifluoropropene, 2,3,3-trifluoropropene,
1,1,1,2-tetrafluoroethane, 1,1,2,2-tetrafluoroethane,
pentafluoroethane, difluoromethane, 1,1-difluoroethane,
1,1,1,2,3,3,3-heptafluoropropane, 1,1,1-trifluoropropane,
1,1,1,3,3,3-hexafluoropropane, 1,1,1,3,3-pentafluoropropane,
1,1,1,3,3-pentafluorobutane, trifluoroiodomethane, and mixtures
comprising them; and especially preferably said heat transfer fluid
comprising or being 2,3,3,3-tetrafluoropropene.
[0044] According to one embodiment, the heat transfer fluid is
admixed with a lubricant preferably selected from mineral oils,
silicone oils, paraffins of natural origin, naphthenes, synthetic
paraffins, alkylbenzenes, poly-alpha-olefins, polyalkylene glycols,
polyol esters and/or polyvinyl ethers; the lubricant being more
preferably a polyalkylene glycol or a polyol ester. The lubricant
content of the refrigerant+lubricant mixture is, for example, from
0.05% to 10% by weight, preferably from 1% to 5%.
[0045] According to one embodiment, the vapor compression circuit
element belongs to a vapor compression circuit integrated in a
device selected from mobile or stationary air conditioning devices,
refrigeration devices, freezing devices, Rankine-cycle and
heat-pump heating devices; and preferably integrated in a motor
vehicle air conditioning device.
[0046] The term "integrated" means that the vapor compression
circuit belongs to the device and that, consequently, the vapor
compression circuit element, which belongs to the vapor compression
circuit, also belongs to the device.
[0047] In other words, the device is composed of a vapor
compression circuit comprising one or more vapor compression
circuit elements.
[0048] According to one embodiment, the vapor compression circuit
element is a connection element or a pipe.
[0049] According to one embodiment, said layer composed of a
composition comprising a copolyamide X/10.T/Y is disposed on an
inner surface of the element.
[0050] According to one embodiment, the vapor compression circuit
element is a multilayer tube, preferably comprising in succession:
[0051] an inner layer which is said layer composed of a composition
comprising a copolyamidex X/10.T/Y; [0052] optionally, a first
intermediate layer disposed above said layer, composed of a first
composition comprising an elastomeric material; [0053] optionally,
a second intermediate layer disposed above said layer, composed of
a reinforcing textile; [0054] an outer layer disposed above said
layer, composed of a second composition comprising an elastomeric
material;
[0055] each composition comprising an elastomeric material being
preferably a composition comprising an ethylene-propylene rubber or
an ethylene-propylene-diene monomer rubber.
[0056] According to one embodiment, the vapor compression circuit
element is an extruded article.
[0057] The invention also provides a heat transfer device
comprising a vapor compression circuit which comprises at least one
vapor compression circuit element as described above, and
preferably a plurality of such elements.
[0058] According to one embodiment, the heat transfer device is
selected from mobile or stationary air conditioning devices,
refrigeration devices, freezing devices, Rankine-cycle and
heat-pump heating devices; said device preferably being a motor
vehicle air conditioning device.
[0059] According to one embodiment, the vapor compression circuit
contains a heat transfer fluid selected from hydrocarbon,
hydrofluorocarbon (HFO), ether, hydrofluoroether, or fluoroolefin
compounds, more particularly from fluoropropenes, fluoropropanes,
and fluoroethanes; and preferably from 1,3,3,3-tetrafluoropropene,
2,3,3,3-tetrafluoropropene, 1,2,3,3,3-pentafluoropropene,
1,1,3,3-tetrafluoropropene, 3,3,3-trifluoropropene,
2,3,3-trifluoropropene, 1,1,1,2-tetrafluoroethane,
1,1,2,2-tetrafluoroethane, pentafluoroethane, difluoromethane,
1,1-difluoroethane, 1,1,1,2,3,3,3-heptafluoropropane,
1,1,1-trifluoropropane, 1,1,1,3,3,3-hexafluoropropane,
1,1,1,3,3-pentafluoropropane, 1,1,1,3,3-pentafluorobutane,
trifluoroiodomethane, and mixtures comprising them; and very
preferably said heat transfer fluid comprises or is
2,3,3,3-tetrafluoropropene.
[0060] According to one embodiment, the heat transfer fluid is
admixed with a lubricant, preferably selected from mineral oils,
silicone oils, paraffins of natural origin, naphthenes, synthetic
paraffins, alkylbenzenes, poly-alpha-olefins, polyalkylene glycols,
polyol esters and/or polyvinyl ethers; the lubricant being more
preferably a polyalkylene glycol or a polyol ester.
[0061] The invention also provides the use of a layer composed of a
composition comprising a copolyamide of formula X/10.T/Y for
transporting a heat transfer fluid in a vapor compression circuit
in which. [0062] X represents alternatively the residues of an
aliphatic amino acid comprising from 8 to 18 carbon atoms, or the
unit X.sub.1.X.sub.2 which represents the residues resulting from
the condensation of an aliphatic diamine comprising from 6 to 18
carbon atoms and a (cyclo)aliphatic dicarboxylic acid comprising
from 6 to 18 carbon atoms; [0063] 10.T represents the residues from
the condensation of a decane diamine and terephthalic acid; and
[0064] Y represents from the condensation of an aliphatic diamine
comprising from 9 to 14 carbon atoms and an aromatic dicarboxylic
acid;
[0065] the molar proportion of units 10.T being greater than
0%;
[0066] the molar proportion of the units Y relative to the total of
units 10.T and Y being from 0% to 30%; and
[0067] the proportion of units X being from 0.4 to 0.8 mol per mole
of aromatic units 10.T and Y.
[0068] According to one embodiment, the composition is as described
above.
[0069] According to one embodiment, the heat transfer fluid is as
described above.
[0070] According to one embodiment, the layer composed of a
composition comprising a copolyamide X/10.T/Y is a layer of a vapor
compression circuit element as described above.
[0071] The invention also provides a method for heating or cooling
a liquid or a body by means of a vapor compression circuit
containing a heat transfer fluid, said method comprising in
succession the evaporation of the heat transfer fluid, the
compression of the heat transfer fluid, the condensation of the
heat fluid, and the expansion of the heat transfer fluid, wherein
the vapor compression circuit comprises a vapor compression circuit
element as described above.
[0072] According to one embodiment, this method for heating or
cooling is a method for heating, air conditioning, refrigerating,
or freezing, and preferably is a method for air conditioning in a
motor vehicle.
[0073] According to one embodiment, the heat transfer fluid used in
the heating or the cooling is as described above.
[0074] The invention also provides a method for producing the
circuit element as described above, comprising a step of applying a
layer of a composition comprising a copolyamide of formula
X/10.T/Y.
[0075] According to one embodiment, this layer is applied by
injection molding, extrusion, extrusion-blow molding, coextrusion,
or multiple injection molding.
[0076] According to one embodiment, the circuit element is a
multilayer tube as described above, the method for producing this
element comprising the successive extrusion, on a mandrel, of the
inner layer, optionally of the first intermediate layer, optionally
of the second intermediate layer then of the outer layer.
[0077] The present invention allows the drawbacks of the prior art
to be overcome. It provides more particularly a composition based
on semi-aromatic copolyamide that allows to be produced vapor
compression circuit elements exhibiting an effective compromise
between their properties of imperviosity to the heat transfer
fluid, to water, and to oxygen, their chemical resistance to the
heat transfer fluid, to water, and to oxygen, their mechanical
strength, their flexibility, and their heat resistance, all of this
especially within the field of motor vehicle air conditioning, and
especially when the heat transfer fluid is a HFO such as R-1234yf,
admixed with a lubricant such as a PAG or POE oil.
[0078] Relative to the PA 6 polyamide-based compositions which are
in use at present in the trade as an inner layer for multilayer
tubes for motor vehicle air conditioning vapor compression
circuits, the compositions of the invention allow the production of
a layer having, in particular, enhanced: [0079] barrier properties
to heat transfer fluids (especially R-1234yf, but also R-134a, for
example); and/or [0080] dimensional stability properties with
respect to water; and/or [0081] barrier properties with respect to
water; and/or [0082] chemical and thermal stability properties in
the presence of R-1234yf and PAG-type lubricant; and/or [0083]
long-term thermal stability properties; and/or [0084] flexibility
properties.
[0085] Relative to the compositions based on polyphthalamide PA 6.T
or PA 9.T that are mentioned in some of the documents set out
above, the compositions of the invention allow the production of a
layer having, in particular, enhanced: [0086] dimensional stability
properties with respect to water; and/or [0087] barrier properties
with respect to water; and/or [0088] long-term thermal stability
properties; and/or [0089] flexibility properties; and/or [0090]
properties of adhesion to an elastomer; and/or [0091] shaping
properties (capacity for conversion).
BRIEF DESCRIPTION OF THE DRAWINGS
[0092] The FIGURE schematically shows a multilayer tube according
to one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0093] The invention is now described in greater detail, without
limitation, in the description which follows.
Semi-Aromatic Copolyamide Used According to the Invention
[0094] The nomenclature used in defining the polyamides is
described in standard ISO 1874-1:1992 "Plastics--Polyamide (PA)
molding and extrusion materials--Part 1: Designation", particularly
on page 3 (tables 1 and 2).
[0095] The invention resides in the use of a semi-aromatic
copolyamide of general formula X/10.T/Y, on the understanding that
this formula covers both copolymers X/10.T (containing only units X
and 10.T) and terpolymers X/10.T/Y (containing units X, 10.T, and
Y).
[0096] Hereinafter, the copolyamide X/10.T/Y is called "copolyamide
of the invention" and the composition containing this copolyamide
is called "composition of the invention" for greater
simplicity.
[0097] It is recalled that X represents alternatively the residues
of an aliphatic amino acid comprising from 8 to 18 carbon atoms, or
the unit X.sub.1.X.sub.2 which represents the radicals resulting
from the condensation of a diamine comprising from 6 to 18 carbon
atoms and a (cyclo)aliphatic diacid comprising from 6 to 18 carbon
atoms; that 10.T represents the residues from the condensation of a
decanediamine and terephthalic acid, in stochiometric proportions;
and that Y represents the residues from the condensation of an
aliphatic diamine comprising from 9 to 14 carbon atoms and an
aromatic dicarboxylic acid (Y is different from the unit 10.T, the
latter already being present in the copolyamide in any case).
[0098] The decanediamine condensed with the terephthalic acid (unit
10.T) may be linear or branched, or a mixture of two or more
decanediamines. The diamine in question is preferably
1,10-decanediamine (linear), which is less sensitive to water.
[0099] As far as the unit Y is concerned, the diamine may be linear
or branched, preferably linear, and may comprise 9, or 10, or 11,
or 12, or 13, or 14 carbon atoms. The aromatic dicarboxylic acid
may in particular be terephthalic acid or isophthalic acid. The
length of the diamine chain is important for the water resistance
of the copolyamide.
[0100] Y may in particular represent the units 9.T, 12.T, 14.T, or
10.I (I referring to isophthalic acid).
[0101] The molar proportion of units Y, relative to the entirety
(the sum) of the units 10.T and Y, is from 0% to 30%, preferably
from 0% to 20%, and more preferably from 0% to 10%.
[0102] The proportion of units X is from 0.4 to 0.8 mol per mole of
semi-aromatic units (that is, per mole of the entirety of units
10.T and, where appropriate, Y), preferably from 0.5 to 0.7 per
mole of aromatic units.
[0103] According to one embodiment, the copolyamide X/10.T/Y is
devoid of units Y.
[0104] X may be selected from a unit obtained from an amino acid, a
unit obtained from a lactam, and a unit X.sub.1.X.sub.2
corresponding to the formula (Ca aliphatic diamine).(Cb
(cyclo)aliphatic dicarboxylic acid), where a represents the number
of carbon atoms in the diamine and b represents the number of
carbon atoms in the dicarboxylic acid, a and b each being between 6
and 18 (endpoints included).
[0105] The copolyamide X/10.T/Y advantageously has a
polymolecularity index, abbreviated Ip, of less than or equal to
3.5. The polymolecularity index of said copolyamide is preferably
between 2.0 and 3.0 (endpoints included).
[0106] This index is measured conventionally and as known to the
skilled person by size exclusion chromatography or gel permeation
chromatography. The polymolecularity index of the copolyamides of
the invention is preferably measured by gel permeation
chromatography. More particularly it is measured in a solvent
appropriate for the copolyamide, such as a fluorinated solvent, as
for example hexafluoroisopropanol, at a temperature of between
20.degree. C. and 50.degree. C., preferably at 40.degree. C.
[0107] It is specified that the expression "between", used in the
preceding paragraphs, but also in the remainder of the present
description, should be understood as including each of the
endpoints stated.
[0108] With regard more specifically to the meaning of the unit X,
when X represents an amino acid, it may be selected in particular
from 9-aminononanoic acid (X=9), 10-aminodecanoic acid (X=10),
10-aminoundecanoic acid (X=11), 12-aminododecanoic acid (X=12), and
11-aminoundecanoic acid (X=11) and its derivatives, especially
N-heptyl-11-aminoundecanoic acid.
[0109] In place of an amino acid, consideration may also be given
to a mixture of two, three, etc., or more amino acids such as
described here. The copolyamides formed then comprise three, four,
etc., or more units, respectively.
[0110] When X represents a lactam, it may be selected from
caprylolactam, pelargolactam, decanolactam, undecanolactam, and
lauryllactam (X=12).
[0111] X preferably denotes a unit obtained from a monomer selected
from 10-aminoundecanoic acid (coded 11), 11-aminoundecanoic acid
(coded 11), 12-aminododecanoic acid (coded 12), and lauryllactam
(coded L12).
[0112] Among the combinations which can be contemplated, the
following copolyamides are of particular interest: copolyamides
conforming to one of the formulae selected from 11/10.T and
12/10.T.
[0113] When the unit X is a unit conforming to the formula
X.sub.1.X.sub.2, the unit (Ca diamine) is selected from linear or
branched aliphatic diamines.
[0114] When the diamine is linear, of formula
H.sub.2N--(CH.sub.2).sub.a--NH.sub.2, the monomer (Ca diamine) is
preferably selected from hexanediamine (a=6), heptanediamine (a=7),
octanediamine (a=8), nonanediamine (a=9), decanediamine (a=10),
undecanediamine (a=11), dodecanediamine (a=12), tridecanediamine
(a=13), tetradecanediamine (a=14), hexadecanediamine (a=16),
octadecanediamine (a=18), octadecenediamine (a=18), and diamines
obtained from fatty acids.
[0115] When the diamine is branched, it may comprise one or more
methyl or ethyl substituents on the main chain. For example, the
monomer (Ca diamine) may advantageously be selected from
2,2,4-trimethyl-1,6-hexanediamine,
2,4,4-trimethyl-1,6-hexanediamine, 2-methyl-1,5-pentanediamine, and
2-methyl-1,8-octanediamine.
[0116] The expression "monomer (Cb (cyclo)aliphatic dicarboxylic
acid)" refers to an aliphatic monomer, which may be linear or
branched, or a cycloaliphatic monomer.
[0117] When the monomer (Cb dicarboxylic acid) is aliphatic and
linear, it is selected from adipic acid (b=6), heptanedioic acid
(b=7), octanedioic acid (b=8), azelaic acid (b=9), sebacic acid
(b=10), undecanedioic acid (b=11), dodecanedioic acid (b=12),
brassylic acid (b=13), tetradecanedioic acid (b=14),
hexadecanedioic acid (b=16), octadecanedioic acid (b=18), and
octadecenedioic acid (b=18).
[0118] When the dicarboxylic acid is cycloaliphatic, it may
comprise the following carbon frameworks: norbornylmethane,
cyclohexylmethane, dicyclohexylmethane, dicyclohexylpropane,
di(methylcyclohexyl)propane.
[0119] Among all of the possible combinations for copolyamides
X/10.T in which X is a (Ca aliphatic diamine).(Cb (cyclo)aliphatic
dicarboxylic acid) unit, those employed in particular will be
copolyamides conforming to one of the formulae selected from
6.10/10.T, 6.12/10.T, 10.6/10.T, 10.10/10.T, 10.12/10.T,
12.12/10.T, and 10.14/10.T.
[0120] With regard to the terpolymers X/10.T/Y (with units Y
present), those employed in particular will be copolyamides
conforming to one of the formulae selected from 11/10.T/10.I,
12/10.T/10.I, 6.10/10.T/10.I, 6.12/10.T/10.I, 10.6/10.T/10.I,
10.10/10.T/10.I, 10.12/10.T/10.I, 12.12/10.T/10.I, and
10.14/10.T/10.I; 11/10.T/9.T, 12/10.T/9.T, 6.10/10.T/9.T,
6.12/10.T/9.T, 10.6/10.T/9.T, 10.10/10.T/9.T, 10.12/10.T/9.T,
12.12/10.T/9.T, and 10.14/10.T/9.T; 11/10.T/12.T, 12/10.T/12.T,
6.10/10.T/12.T, 6.12/10.T/12.T, 10.6/10.T/12.T, 10.10/10.T/12.T,
10.12/10.T/12.T, 12.12/10.T/12.T, and 10.14/10.T/12.T;
11/10.T/14.T, 12/10.T/14.T, 6.10/10.T/14.T, 6.12/10.T/14.T,
10.6/10.T/14.T, 10.10/10.T/14.T, 10.12/10.T/14.T, 12.12/10.T/14.T,
and 10.14/10.T/14.T.
[0121] Although the majority of the comonomers or starting products
contemplated in the present description (amino acids, diamines,
dicarboxylic acids) are saturated, there is nothing to prevent the
possibility that they may be partially unsaturated.
[0122] Mention may be made, for example, of the fact that the C18
dicarboxylic acid may be octadecanedioic acid, which is saturated,
or else octadecenedioic acid, which itself has an unsaturation.
[0123] The copolyamide of the invention may comprise monomers
originating from resources resulting from renewable raw materials,
in other words comprising organic carbon obtained from biomass and
determined according to standard ASTM D6866. These monomers
resulting from renewable raw materials may be 1,10-decanediamine
or, when present, in particular, 11-aminoundecanoic acid, and the
aliphatic and linear dicarboxylic acids and diamines as defined
above.
[0124] The copolyamides of the invention may be prepared by
polycondensation of the above-defined comonomers, in the presence,
for example, of hypophosphorous acid or at least one of its
salts.
[0125] The detailed description of a polycondensation process of
this kind is contained in particular in document WO
2010/015786.
[0126] More particularly, according to a first embodiment, this
process comprises the single step of reacting the amino acid X (or
the Ca and Cb dicarboxylic acids and diamines) and the
stochiometric combination of decanediamine and terephthalic acid
(and optionally isophthalic acid), in the presence of sodium
hypophosphite, water, and optionally other additives. The time,
temperature, and pressure conditions are described in greater
detail in document WO 2010/015786.
[0127] According to a second embodiment, this process comprises two
steps. The first step leads to a diacidic oligomer, which undergoes
polycondensation during the second step with the decanediamine,
according to the following sequence: first reaction step of the
terephthalic acid (and optionally isophthalic acid) with the amino
acid X, in the presence of a hypophosphite salt; and second
reaction step of the diacidic oligomer thus formed in the preceding
step with decanediamine. The time, temperature, and pressure
conditions are described in greater detail in document WO
2010/015786. Where X is a (Ca aliphatic diamine).(Cb
(cyclo)aliphatic dicarboxylic acid) mixture, it is possible to
introduce from 10% to 100% by weight of the Ca diamine in the first
reaction step, any remainder of the Ca diamine being introduced
with the Cb (cyclo)aliphatic dicarboxylic acid in the second
reaction step.
[0128] According to a third embodiment, this process comprises two
steps: first reaction step of the amino acid X with terephthalic
acid (and optionally isophthalic acid), and with 10% to 90% by
weight of decanediamine, in the presence of a hypophosphite salt;
and second reaction step of the oligomer produced in the first step
with the balance of the decanediamine in one or more portions. The
time, temperature, and pressure conditions are described in greater
detail in document WO 2010/015786. Where X is a (Ca aliphatic
diamine).(Cb (cyclo)aliphatic dicarboxylic acid) mixture, it is
possible to introduce from 10% to 100% by weight of the Ca diamine
in the first reaction step, any remainder of the Ca diamine being
introduced with the Cb (cyclo)aliphatic dicarboxylic acid in the
second reaction step.
[0129] According to a fourth embodiment, this process comprises two
steps: first reaction step of the amino acid X with terephthalic
acid (and optionally isophthalic acid) and all of the diamine, in
the presence of a hypophosphite salt; an oligomer is obtained by
discharging of the reactor under steam pressure and crystallization
of said oligomer; second step of post polymerization at atmospheric
pressure or under vacuum of the oligomer produced in the first
step. The time, temperature, and pressure conditions are described
in greater detail in document WO 2010/015786.
[0130] The polycondensation processes according to the present
invention may be performed in any reactor conventionally used in
polymerization, such as reactors with anchor or ribbon stirrers.
Continuous polymerization processes are likewise possible. However,
when the process comprises a second step, as defined above, it may
also be performed in a horizontal or finisher reactor, known more
commonly by the skilled person as a "finisher". The finishers may
be equipped with a device for implementing vacuum or for
introducing reactant (addition of diamine), which may be staged or
otherwise, and may operate within a wide temperature range.
[0131] At the end of this process or during the second step (when
the process comprises two steps), as well as the balance of
diamine, it is possible to admix the copolyamide X/10.T/Y with
customary additives for polyamides, as defined hereinafter. The
additives to the copolyamide of the invention are present
preferably in an amount of 1% to 70%, more preferably of 5% to 60%,
or of 15% to 50%, by weight relative to the weight of the
composition.
[0132] The copolyamide X/10.T/Y according to the invention
preferably has an amine chain end content of greater than or equal
to 20 .mu.eq/g, an acid chain end content of less than 100
.mu.eq/g, and a nonreactive chain end content of greater than or
equal to 20 .mu.eq/g.
[0133] The chain end content of each of the amine, acid, and
nonreactive functions is measured conventionally by NMR (Nuclear
Magnetic Resonance).
[0134] Preferably the amine chain end content is between 25 and 100
.mu.eq/g, and preferably between 30 and 58 .mu.eq/g.
[0135] Preferably the acid chain end content is between 2 and 80
.mu.eq/g, and preferably between 15 and 50 ueq/g.
[0136] Preferably the nonreactive chain end content is
advantageously greater than or equal to 30 .mu.eq/g, and preferably
between 35 and 200 .mu.eq/g.
[0137] To adjust the chain end content, it is possible to use chain
termination agents, these being compounds capable of reacting with
the terminal amine and/or carboxylic acid functions of the
polyamides, thereby stopping the reactivity of the end of the
macromolecule, and hence the polycondensation.
[0138] The chain termination agents appropriate for reaction with
the terminal amine function may be monocarboxylic acids,
anhydrides, such as phthalic anhydride, monohalogenated acids,
monoesters, or monoisocyanates. Monocarboxylic acids are used with
preference. They may be selected from monocarboxylic aliphatic
acids, such as acetic acid, propionic acid, lactic acid, valeric
acid, caproic acid, capric acid, uric acid, tridecylic acid,
myristic acid, palmitic acid, stearic acid, pivalic acid, and
isobutyric acid; alicyclic acids, such as cyclohexanecarboxylic
acid; monocarboxylic aromatic acids such as toluic acid,
.alpha.-naphthalenecarboxylic acid, .beta.-naphthalenecarboxylic
acid, methylnaphthalenecarboxylic acid, and phenylacetic acid; and
mixtures thereof. Preferred compounds are the aliphatic acids, and
especially acetic acid, propionic acid, lactic acid, valeric acid,
caproic acid, capric acid, lauric acid, tridecylic acid, myristic
acid, palmitic acid, and stearic acid.
[0139] The chain termination agents appropriate for reaction with
the terminal acid function may include monoamines, monoalcohols,
and monoisocyanates. Monoamines are used with preference. They may
be selected from aliphatic monoamines, such as methylamine,
ethylamine, propylamine, butylamine, hexylamine, octylamine,
decylamine, laurylamine, stearylamine, dimethylamine, diethylamine,
dipropylamine, and dibutylamine; alicyclic amines, such as
cyclohexylamine and dicyclohexylamine; aromatic monoamines, such as
aniline, toluidine, diphenylamine, and naphthylamine; and mixtures
thereof.
[0140] The preferred compounds are butylamine, hexylamine,
octylamine, decylamine, laurylamine, stearylamine, cyclohexylamine,
and aniline.
[0141] It is also possible to react the acid and/or amine ends,
respectively, with inorganic bases such as alkali metal and
alkaline earth metal hydroxides, such as potassium hydroxide and
sodium hydroxide, and with inorganic acids such as HCl, HNO.sub.3,
and H.sub.2SO.sub.4.
[0142] The chain termination agents may be introduced during the
first and/or second steps, in the case of the two-step production
processes of the copolyamide X/10.T/Y described above. For more
details, reference is made here to document WO 2010/015785.
[0143] According to one embodiment, the composition of the
invention comprises a single copolyamide X/10.T/Y as described
above (and no other polyamide).
[0144] According to one variant, the composition of the invention
comprises two or a plurality of different copolyamides X/10.T/Y as
described above.
[0145] According to one variant, the composition of the invention
comprises, further to the copolyamide or copolyamides X/10.T/Y as
described above, one or more additional polyamides (see below).
Polyolefins
[0146] The composition of the invention optionally and
advantageously comprises from 5% to 40%, and preferably from 12% to
36%, by weight of at least one polyolefin.
[0147] The function of the polyolefins is that in particular of
flexibilizing the composition and/or endowing it with impact
resistance and/or of enhancing its dimensional stability with
respect to water (by virtue of their hydrophobic character).
[0148] The polyolefins used may be selected from crosslinked
polyolefins, functionalized polyolefins, and mixtures thereof, and
optionally other polyolefins. Functionalized polyolefins are
advantageously present in the composition.
[0149] A crosslinked polyolefin may take the form of a phase
dispersed in the matrix formed by the polyamide or polyamides.
[0150] This crosslinked polyolefin originates from the reaction of
two or at least two products having groups which react with one
another.
[0151] More particularly, the crosslinked polyolefin is obtained
from at least one product (A) comprising an unsaturated epoxide and
at least one product (B) comprising an unsaturated carboxylic
anhydride.
[0152] The product (A) is advantageously a polymer comprising an
unsaturated epoxide, this unsaturated epoxide being introduced into
said polymer either by grafting or by copolymerization.
[0153] The unsaturated epoxide may in particular be selected from
the following epoxides: [0154] aliphatic glycidyl esters and ethers
such as allyl glycidyl ether, vinyl glycidyl ether, glycidyl
maleate and itaconate, glycidyl acrylate and methacrylate, and
[0155] alicyclic glycidyl esters and ethers such as 2-cyclohexene
1-glycidyl ether, diglycidyl cyclohexene-4,5-carboxylate, glycidyl
cyclohexene-4-carboxylate, glycidyl
5-norbornene-2-methyl-2-carboxylate, and diglycidyl
endo-cis-bicyclo [2,2,1]-5-heptene-2,3-dicarboxylate.
[0156] According to a first form, the product (A) is a polyolefin
grafted with an unsaturated epoxide. A polyolefin is understood to
be a homopolymer or copolymer comprising one or more olefin units
such as units of ethylene, propylene, but-1-ene, or any other
alpha-olefin. Examples of polyolefins include the following: [0157]
polyethylene and, in particular, low-density polyethylene (LDPE),
high-density polyethylene (HDPE), linear low-density polyethylene
(LLDPE), and very low-density polyethylene (VLDPE); polypropylene;
ethylene/propylene copolymers; elastomeric polyolefins such as
ethylene-propylene (EPR or EPM) or ethylene-propylene-diene monomer
(EPDM); or else metallocene polyethylenes obtained by single-site
catalysis; [0158] styrene/ethylene-butene/styrene (SEBS) block
copolymers; styrene/butadiene/styrene (SBS) block copolymers;
styrene/isoprene/styrene (SIS) block copolymers; or else
styrene/ethylene-propylene/styrene block copolymers; [0159]
copolymers of ethylene and at least one product selected from salts
of unsaturated carboxylic acids, esters of unsaturated carboxylic
acids, and vinyl esters of saturated carboxylic acids. The
polyolefin may in particular be a copolymer of ethylene and alkyl
(meth)acrylate, or a copolymer of ethylene and vinyl acetate.
[0160] According to a second form, the product (A) is a copolymer
of alpha-olefin and an unsaturated epoxide and, advantageously, a
copolymer of ethylene and an unsaturated epoxide. The amount of
unsaturated epoxide may advantageously represent up to 15% by
weight of the copolymer (A), with the amount of ethylene itself
representing at least 50% by weight of the copolymer (A).
[0161] Mention may be made in particular of copolymers of ethylene,
a vinyl ester of saturated carboxylic acid, and an unsaturated
epoxide, and of copolymers of ethylene, an alkyl (meth)acrylate,
and an unsaturated epoxide. The alkyl of the (meth)acrylate
preferably comprises from 2 to 10 carbon atoms. Examples of alkyl
acrylates or methacrylates which can be used are, in particular,
methyl acrylate, methyl methacrylate, ethyl acrylate, n-butyl
acrylate, isobutyl acrylate, and 2-ethylhexyl acrylate.
[0162] According to one advantageous version of the invention, the
product (A) is a copolymer of ethylene, methyl acrylate, and
glycidyl methacrylate, or a copolymer of ethylene, n-butyl
acrylate, and glycidyl methacrylate. It will also be possible in
particular to use the product sold by Arkema under the name
LOTADER.RTM. AX8900.
[0163] According to another form of the invention, the product (A)
is a product having two epoxide functions, such as bisphenol A
diglycidyl ether (BADGE).
[0164] The product (B) is advantageously a polymer comprising an
unsaturated carboxylic anhydride, this unsaturated carboxylic
anhydride being introduced into said polymer either by grafting or
by copolymerization.
[0165] Examples of unsaturated dicarboxylic anhydrides which can be
used as constituents of the product (B) are, in particular, maleic
anhydride, itaconic anhydride, citraconic anhydride, and
tetrahydrophthalic anhydride.
[0166] According to a first form, the product (B) is a polyolefin
grafted with an unsaturated carboxylic anhydride. As has been seen
above, a polyolefin is a homopolymer or copolymer comprising one or
more olefin units such as units of ethylene, propylene, but-1-ene,
or any other alpha-olefin. This polyolefin may in particular be
selected from the examples of polyolefins listed earlier on above
for the product (A), when the latter is a polyolefin grafted with
an unsaturated epoxide.
[0167] According to a second form, the product (B) is a copolymer
of alpha-olefin and an unsaturated carboxylic anhydride and,
advantageously, is a copolymer of ethylene and an unsaturated
carboxylic anhydride.
[0168] The amount of unsaturated carboxylic anhydride
advantageously may represent up to 15% by weight of the copolymer
(B), with the amount of ethylene representing at least 50% by
weight of the copolymer (B).
[0169] Mention may be made more particularly of copolymers of
ethylene, a vinyl ester of saturated carboxylic acid, and an
unsaturated carboxylic anhydride, and also of copolymers of
ethylene, an alkyl (meth)acrylate, and an unsaturated carboxylic
anhydride. The alkyl of the (meth)acrylate preferably comprises
from 2 to 10 carbon atoms. The alkyl acrylate or methacrylate may
be selected from those given earlier on above for the product
(A).
[0170] According to an advantageous version of the invention, the
product (B) is a copolymer of ethylene, an alkyl (meth)acrylate,
and an unsaturated carboxylic anhydride. Preferably the product (B)
is a copolymer of ethylene, ethyl acrylate, and maleic anhydride,
or a copolymer of ethylene, butyl acrylate, and maleic anhydride.
It will be possible in particular to use the products sold by
Arkema under the names LOTADER.RTM. 4700 and LOTADER.RTM. 3410.
[0171] It would not be departing the scope of the invention if a
part of the maleic anhydride of the product (B), according to the
first and second forms which have just been described, was partly
hydrolyzed.
[0172] According to one particular embodiment of the invention, the
amounts by weight of product (A) and of product (B), coded
respectively as [A] and [B], may be such that the ratio [B]/[A] is
between 3 and 14, and advantageously between 4 and 9.
[0173] In the composition according to the invention, the
crosslinked polyolefin may also be obtained from products (A) and
(B) as described above and from at least one product (C), this
product (C) comprising an unsaturated carboxylic acid or an
alpha,omega-aminocarboxylic acid.
[0174] The product (C) is advantageously a polymer comprising an
unsaturated carboxylic acid or an alpha,omega-aminocarboxylic acid,
one or other of these acids being introduced into said polymer by
copolymerization.
[0175] Examples of unsaturated carboxylic acids which can be used
as constituents of the product (C) are, in particular, acrylic
acid, methacrylic acid, and the carboxylic anhydrides stated above
as constituents of the product (B), these anhydrides being
completely hydrolyzed.
[0176] Examples of alpha,omega-aminocarboxylic acids which can be
used as constituents of the product (C) are, in particular,
6-aminohexanoic acid, 11-aminoundecanoic acid, and
12-aminododecanoic acid.
[0177] The product (C) may be a copolymer of alpha-olefin and an
unsaturated carboxylic acid, and, advantageously, a copolymer of
ethylene and an unsaturated carboxylic acid. Mention may be made in
particular of the completely hydrolyzed copolymers of the product
(B). According to an advantageous version of the invention, the
product (C) is a copolymer of ethylene and (meth)acrylic acid, or a
copolymer of ethylene, an alkyl (meth)acrylate, and (meth)acrylic
acid. The amount of (meth)acrylic acid may represent up to 10% by
weight and, preferably from 0.5% to 5% by weight of the copolymer
(C). The amount of alkyl (meth)acrylate is generally between 5% and
40% by weight of the copolymer (C).
[0178] The product (C) is preferably a copolymer of ethylene, butyl
acrylate, and acrylic acid. It will be possible in particular to
use the product sold by BASF under the name LUCALENE.RTM. 3110.
[0179] According to one particular embodiment of the invention, the
amounts by weight of product (A), of product (B), and of product
(C), coded respectively [A], [B], and [C], may be such that the
ratio [B]/([A]+[C]) is between 1.5 and 8, the amounts by weight of
products (A) and (B) being such that [C].ltoreq.[A].
[0180] Advantageously, the ratio [B]/([A]+[C]) may be between 2 and
7.
[0181] The dispersed, crosslinked polyolefin phase may of course
originate from the reaction of one or more products (A) with one or
more products (B) and, where appropriate, with one or more products
(C).
[0182] It is possible to use catalysts which allow the reaction of
the reactive functions of the products (A) and (B) to be
accelerated. Reference may be made in particular to the teaching of
document WO 2011/015790 with regard to examples of catalysts, it
being possible for the latter to be used in an amount by weight of
between 0.1% and 3% and, advantageously, between 0.5% and 1% of the
total weight of the products (A), (B), and, where appropriate
(C).
[0183] Preferably, when the polyolefin is a crosslinked polyolefin,
it is present in the composition in an amount of between 13% and
40% by weight, relative to the total weight of the composition.
[0184] The composition of the invention may comprise, furthermore,
at least one functionalized polyolefin (D).
[0185] According to the invention, functionalized polyolefin (D)
means the polymers below.
[0186] The functionalized polyolefin (D) may be an alpha-olefin
polymer having reactive units: the functionalities. Reactive units
of these kinds are carboxylic acid, anhydride, or epoxy
functions.
[0187] As an example, mention may be made as polyolefins of
homopolymers or copolymers of alpha-olefins or diolefins, such as,
for example, ethylene, propylene, but-1-ene, oct-1-ene, and
butadiene, and more particularly: [0188] homopolymers and
copolymers of ethylene, especially LDPE, HDPE, LLDPE (linear
low-density polyethylene), VLDPE (very low density polyethylene),
and metallocene polyethylene, [0189] homopolymers or copolymers of
propylene, [0190] ethylene/alpha-olefin copolymers such as
ethylene/propylene copolymers, EPRs (ethylene-propylene rubber),
and EPDMs (terpolymer based on ethylene/propylene/diene), [0191]
styrene/ethylene-butene/styrene (SEBS), styrene/butadiene/styrene
(SBS), styrene/isoprene/styrene (SIS), and
styrene/ethylene-propylene/styrene (SEPS) block copolymers, [0192]
copolymers of ethylene with at least one product selected from the
salts or esters of unsaturated carboxylic acids, such as alkyl
(meth)acrylate (for example, methyl acrylate), or the vinyl esters
of saturated carboxylic acids, such as vinyl acetate (EVA), the
proportion of comonomer possibly reaching 40% by weight.
[0193] These above-described polyolefins may be grafted,
copolymerized, or terpolymerized with reactive units (the
functionalities), such as carboxylic acid, anhydride, or epoxy
functions.
[0194] More particularly, these polyolefins are grafted or co- or
ter-polymerized with unsaturated epoxides such as glycidyl
(meth)acrylate, or with carboxylic acids or the corresponding salts
or esters, such as (meth)acrylic acid (which may be fully or
partially neutralized by metals such as Zn, etc.) or else with
carboxylic anhydrides such as maleic anhydride.
[0195] The functionalized polyolefin (D) may be selected from the
following (co)polymers, grafted with maleic anhydride or glycidyl
methacrylate, in which the degree of grafting is, for example, from
0.01% to 5% by weight: [0196] PE (polyethylene), PP
(polypropylene), copolymers of ethylene with propylene, butene,
hexene, or octene, containing for example from 35% to 80% of
ethylene; [0197] ethylene/alpha-olefin such as ethylene-propylene
copolymers, EPRs, and EPDMs, [0198] SEBS, SBS, SIS, and SEPS block
copolymers, [0199] EVA copolymers, containing up to 40% by weight
of vinyl acetate, [0200] copolymers of ethylene and alkyl
(meth)acrylate, containing up to 40% by weight of alkyl
(meth)acrylate, [0201] copolymers of ethylene and EVA and alkyl
(meth)acrylate, containing up to 40% by weight of comonomers.
[0202] A functionalized polyolefin is, for example, a PE/EPR blend
in which the ratio by weight may vary within broad degrees, as for
example between 40/60 and 90/10, said blend being co-grafted with
an anhydride, especially maleic anhydride, according to a degree of
grafting, for example, of 0.01% to 5% by weight.
[0203] The functionalized polyolefin (D) may also be selected from
majority-propylene ethylene/propylene copolymers grafted with
maleic anhydride and then condensed with mono-amino polyamide (or a
polyamide oligomer) (products described in EP-A-0342066).
[0204] The functionalized polyolefin (D) may also be a copolymer or
a terpolymer of at least one of the following units:
[0205] (1) ethylene,
[0206] (2) alkyl (meth)acrylate or vinyl ester of saturated
carboxylic acid, and
[0207] (3) anhydride such as maleic anhydride or (meth)acrylic acid
or epoxy such as glycidyl (meth)acrylate.
[0208] Examples of functionalized polyolefins of this latter type
include the following copolymers, in which ethylene represents at
least preferably 60% by weight and in which the termonomer
represents for example from 0.1% to 12% by weight of the copolymer:
[0209] ethylene/alkyl (meth)acrylate/(meth)acrylic acid or maleic
anhydride or glycidyl methacrylate copolymers; [0210]
ethylene/vinyl acetate/maleic anhydride or glycidyl methacrylate
copolymers; [0211] ethylene/vinyl acetate or alkyl
(meth)acrylate/(meth)acrylic acid or maleic anhydride or glycidyl
methacrylate copolymers.
[0212] In the preceding copolymers, the (meth)acrylic acid may be
salified by the salts of Zn or Li.
[0213] The term "alkyl meth(acrylate)" (D) denotes C.sub.1 to
C.sub.8 alkyl acrylates and methacrylates; the alkyl meth(acrylate)
may be selected from methyl acrylate, ethyl acrylate, n-butyl
acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, cyclohexyl
acrylate, methyl methacrylate, and ethyl methacrylate.
[0214] Moreover, the aforementioned polyolefins (D) may also be
crosslinked by any appropriate process or agent (diepoxy,
dicarboxylic acid, peroxide, etc.); the "functionalized polyolefin"
also includes mixtures of the aforementioned polyolefins with a
difunctional reactant such as a dicarboxylic acid, dianhydride,
diepoxy, etc., which is capable of reacting with the latter, or
mixtures of at least two functionalized polyolefins which are able
to react with one another.
[0215] The copolymers (D) mentioned above may also be copolymerized
randomly or in sequenced form and may have a linear or branched
structure.
[0216] The molecular weight, the MFI index, and the density of
these polyolefins may also vary to a large degree, as the skilled
person will appreciate. The MFI index is the melt flow index. It is
measured according to standard ASTM 1238.
[0217] The functionalized polyolefins (D) are advantageously
selected from any polymer comprising alpha-olefinic units and units
which bear reactive polar functions such as epoxy, carboxylic acid,
or carboxylic anhydride functions. Examples of such polymers
include terpolymers of ethylene, alkyl acrylate, and maleic
anhydride or glycidyl methacrylate, such as the Lotader.RTM.
products from the applicant company, or polyolefins grafted with
maleic anhydride, such as the Orevac.RTM. products from the
applicant company, and also terpolymers of ethylene, alkyl
acrylate, and (meth)acrylic acid. Mention may also be made of
homopolymers or copolymers of polypropylene which are grafted with
a carboxylic anhydride and then condensed with polyamides or
mono-amino oligomers of polyamide, as described in patent
application EP 0342066.
[0218] More particularly the functionalized polyolefins (D) are:
[0219] terpolymers of ethylene, alkyl acrylate, and maleic
anhydride; [0220] terpolymers of ethylene, alkyl acrylate, and
glycidyl methacrylate; [0221] polypropylenes and polyethylenes
grafted with maleic anhydride; [0222] copolymers of ethylene and of
propylene and optionally of monomeric diene that are grafted with
maleic anhydride; [0223] copolymers of ethylene and octene that are
grafted with maleic anhydride; [0224] and mixtures thereof.
[0225] Preferably, when the polyolefin is a functionalized
polyolefin (D), it is present in an amount of between 10% and 40%
by weight, preferably between 15% and 30% by weight, relative to
the total weight of the composition.
[0226] In addition to a crosslinked and/or functionalized
polyolefin, the composition of the invention may advantageously
comprise at least one nonfunctionalized polyolefin (E).
[0227] A nonfunctionalized polyolefin (E) is conventionally a
homopolymer or copolymer of alpha-olefins or of diolefins, such as,
for example, ethylene, propylene, but-1-ene, oct-1-ene, and
butadiene. The following may be mentioned by way of example: [0228]
polyethylene homopolymers and copolymers, more particularly LDPE,
HDPE, LLDPE (linear low-density polyethylene), VLDPE (very
low-density polyethylene), and metallocene polyethylene, [0229]
homopolymers or copolymers of propylene, [0230]
ethylene/alpha-olefin such as ethylene/propylene copolymers, EPRs,
and EPDMs, [0231] SEBS, SBS, SIS, and SEPS block copolymers, [0232]
copolymers of ethylene with at least one comonomer selected from
salts or esters of unsaturated carboxylic acids, such as alkyl
(meth)acrylate (for example, methyl acrylate), or vinyl esters of
saturated carboxylic acids such as EVA, the proportion of comonomer
possibly reaching 40% by weight, relative to the total weight of
the copolymer, [0233] and mixtures thereof.
[0234] The abovementioned copolymers (E) may be copolymerized
randomly or in sequenced form and may have a linear or branched
structure.
[0235] The nonfunctionalized polyolefins (E) are advantageously
selected from homopolymers or copolymers of polypropylene and any
homopolymer or copolymer of ethylene and a comonomer of
alpha-olefin type higher than propylene, such as butene, hexene,
octene, or 4-methyl-1-pentene. Mention may be made, for example, of
polypropylenes, high-density polyethylenes, medium-density
polyethylenes, linear low-density polyethylenes, low-density
polyethylenes, and very low-density polyethylenes. These
polyethylenes are known by the skilled person as being produced
according to a radical process, according to Ziegler-type
catalysis, or, more recently, according to metallocene catalysis.
Preference is also given to copolymers of ethylene and EVA, such as
those sold under the trade name EVATANE by the applicant
company.
[0236] When the composition of the invention comprises a
nonfunctionalized polyolefin, the latter is present preferably in
an amount of between 5% and 30% by weight, preferably between 10%
and 20% by weight, relative to the total weight of the
composition.
Other Additives
[0237] The composition of the invention advantageously comprises a
plasticizer, preferably in a proportion by mass from 1% to 10%,
more preferably from 2% to 7%, relative to the total mass of the
composition.
[0238] Advantageously, a plasticizer is used which has a high
thermal stability, so as not to form fumes during steps of mixing
of the various polymers and of converting of the resulting
composition.
[0239] This plasticizer may be selected more particularly from:
[0240] benzenesulfonamide derivatives such as
n-butylbenzenesulfonamide (BBSA), ortho and para isomers of
ethyltoluenesulfonamide (ETSA), N-cyclohexyltoluenesulfonamide, and
N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA), [0241] esters of
hydroxybenzoic acids such as 2-ethylhexyl para-hydroxybenzoate
(EHPB) and 2-hexyldecyl para-hydroxybenzoate (HDPB), [0242] esters
or ethers of tetrahydrofurfuryl alcohol such as
oligoethyleneoxy-tetrahydrofurfuryl alcohol, and [0243] esters of
citric acid or hydroxymalonic acid, such as
oligoethyleneoxymalonate.
[0244] A preferred plasticizer, being commonly used, is
n-butylbenzenesulfonamide (BBSA).
[0245] Another particularly preferred plasticizer is
N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA). This is because the
latter has the advantage of preventing the formation of deposits on
the screw and/or on the extrusion die ("die drool") during a step
of conversion by extrusion.
[0246] A mixture of these plasticizers may also be used.
[0247] The composition of the invention advantageously comprises at
least one heat stabilizer.
[0248] The heat stabilizer may be present in an amount of 0% to 4%,
in particular of 0.01% to 2% or of 0.1% to 0.3% by weight, relative
to the total weight of the composition.
[0249] This may be a copper heat stabilizer.
[0250] More particularly it may be a copper salt or a copper salt
derivative, as for example copper iodide, copper bromide, copper
halides, and derivatives or mixtures thereof. Copper(I) salts are
preferred. Examples are copper iodide, copper bromide, copper
chloride, copper fluoride, copper thiocyanate, copper nitrate,
copper acetate, copper naphthenate, copper caprate, copper laurate,
copper stearate, copper acetylacetonate, and copper oxide. Copper
iodide, copper bromide, copper chloride, and copper fluoride are
preferred.
[0251] As a heat stabilizer, consideration may also be given to a
metal halide salt in combination with LiI, NaI, KI, MgI.sub.2, KBr,
or CaI.sub.2. KI and KBr are preferred.
[0252] The copper heat stabilizer is preferably a mixture of
potassium iodide and copper iodide (KI/CuI).
[0253] The mixture of potassium iodide and copper iodide that can
be used according to the present invention is present preferably in
a ratio of 90/10 to 70/30.
[0254] An example of a stabilizer of this kind is Polyadd P201 from
Ciba.
[0255] Greater details concerning the copper-based stabilizer will
be found in U.S. Pat. No. 2,705,227.
[0256] It is also possible to use complexed coppers such as the
Bruggolen H3336, H3337, H3373 products from Brueggemann.
[0257] The composition of the invention preferably comprises from
0.10% to 0.25% by weight of copper heat stabilizer.
[0258] Other possible heat stabilizers are sterically hindered
phenolic antioxidants. These compounds are described in detail in
document US 2012/0279605, in paragraphs [0025] and [0026], to which
reference is made expressly here.
[0259] However, according to an alternative embodiment, the
composition of the invention is devoid of such hindered phenolic
antioxidants.
[0260] Another category of possible stabilizers are the sterically
hindered amine-based UV stabilizers (or HALS), which are
2,2,6,6-tetramethylpiperidine derivatives. They may be used, for
example, in a range from 0% to 1%, or from 0.01% to 0.5%.
[0261] The composition of the invention may be composed solely of
the four classes of compounds, namely at least one polyolefin,
optionally a plasticizer, at least one heat stabilizer (more
particularly a copper stabilizer), and the semi-aromatic
copolyamide.
[0262] However, the composition may also comprise other compounds
in addition to those just mentioned. The composition of the
invention may, in particular, further comprise at least one
additive and/or at least one additional polymer.
[0263] The additional additives may be selected in particular from
adjuvants which aid conversion (or "processing aids"), fillers,
stabilizers other than that defined above, colorants, mold release
agents, flame retardants, surfactants, fluorescent whiteners, and
mixtures thereof.
[0264] Among the colorants, mention may be made in particular of
carbon black. The colorants or pigments may be present for example
at a level of 0.1% to 0.2% by weight.
[0265] Among the processing aids, mention may be made of stearates,
such as calcium or zinc stearates, natural waxes, and polymers
comprising tetrafluoroethylene (TFE).
[0266] The proportion by weight of processing aids is
conventionally between 0.01% and 0.3% by weight, advantageously
between 0.02% and 0.1% by weight, relative to the total weight of
the composition.
[0267] The fillers include silica, graphite, expanded graphite,
carbon black, glass beads, kaolin, magnesia, slags, talc,
nanofillers (carbon nanotubes), metal oxides (titanium oxide),
metals, and fibers (aramids, glass, carbon, or plant fibers),
especially long or short such fibers.
[0268] Depending on the nature of the fillers, the amount thereof
may represent up to 50% by weight, advantageously, up to 30% by
weight, of the total weight of the composition, and for example
from 5% to 30% or from 20% to 30% by weight. The fillers such as
expanded graphite, for example, may enhance the thermal
conductivity of the material (in order, for example, to promote
heat exchange between a chamber of a tube comprising a layer of
composition of the invention and the exterior, or between two
chambers of a tube comprising a layer of composition of the
invention).
[0269] The use of fibers, especially short ones, as for example
glass fibers, in an amount of 10% to 60% by weight, preferably of
20% to 40% by weight, may reinforce the layer formed from the
composition in question (the presence of fibers may be useful, for
example, at one end of the circuit element according to the
invention, in the region of a connection to another component). The
fibers may have a length, for example, of 0.05 to 1 mm, and in
particular of 0.1 to 0.5 mm. Their average diameter may be from 5
to 20 .mu.m, preferably from 6 to 14 .mu.m.
[0270] The composition of the invention may further comprise one or
more additional polymers, and in particular at least one third
polymer, such a polymer being different from the semi-aromatic
copolyamide(s) and from the polyolefin(s) mentioned above.
Alternatively the composition of the invention may have no such
additional polymer.
[0271] The additional polymer may in particular be selected from a
polyamide other than that defined above, a polyamide-block-ether, a
polyetheramide, a polyesteramide, a polyphenylene sulfide (PPS), a
polyphenylene oxide (PPO), a fluoropolymer, and mixtures
thereof.
[0272] The additional polymer is preferably selected from aliphatic
polyamides and polyamide-block-ethers. The aliphatic polyamides
include, in particular, long-chain polyamides such as PA 11, PA 12,
PA 6.10, PA 6.12, PA 6.14, PA 10.10, PA 10.12, and PA 12.12.
[0273] The composition may therefore contain up to 20% by weight of
at least one additional polymer, relative to the total weight of
the composition.
[0274] As an example of a composition of the invention, use may be
made of composition 1, which has the following formulation by mass:
[0275] polyamide PA 11/10.T (0.7 mol of 11-aminocarboxylic acid per
mole of 1,10-decanediamine and terephthalic acid): 55.8%; [0276]
ethylene/ethyl acrylate/maleic anhydride copolymer (mass ratio
69/30/1): 30%; [0277] ethylene/methyl acrylate/glycidyl
methacrylate copolymer (ratio 68/24/8): 6%; [0278] HP-BSA: 7%;
[0279] heat stabilizer composed of 80% KI, 10% CuI, and 10% calcium
stearate: 0.7%; [0280]
4,4'-bis(alpha,alpha-dimethylbenzyl)diphenylamine antioxidant:
0.5%.
[0281] As an example of the composition of the invention, use may
also be made of composition 2, which has the following formulation
by mass: [0282] polyamide PA 11/10.T (0.5 mol of 11-aminocarboxylic
acid per mole of 1,10-decanediamine and terephthalic acid): 68.25%;
[0283] ethylene/ethyl acrylate/maleic anhydride copolymer (mass
ratio 69/30/1): 24%; [0284] ethylene/methyl acrylate/glycidyl
methacrylate copolymer (ratio 68/24/8): 4%; [0285] ethylene/butyl
acrylate/acrylic acid copolymer (ratio 88/8/4): 2%; [0286] heat
stabilizer composed of 80% KI, 10% CuI, and 10% calcium stearate:
0.25%; [0287] 4,4'-bis(alpha,alpha-dimethylbenzyl)diphenylamine
antioxidant: 0.5%; [0288] various additives: 1% (including carbon
black).
[0289] As an example of the composition of the invention, use may
also be made of composition 3, which has the following formulation
by mass: [0290] polyamide PA 11/10.T (0.7 mol of 11-aminocarboxylic
acid per mole of 1,10-decanediamine and terephthalic acid): 68.25%;
[0291] ethylene/ethyl acrylate/maleic anhydride copolymer (mass
ratio 69/30/1): 15%; [0292] ethylene/methyl acrylate/glycidyl
methacrylate copolymer (ratio 68/24/8): 7.5%; [0293] ethylene/butyl
acrylate/acrylic acid copolymer (ratio 88/8/4): 7.5%; [0294]
stabilizer: 0.7%; [0295] various additives: 1.05% (including carbon
black).
[0296] As an example of the composition of the invention, use may
also be made of composition 4, which has the following formulation
by mass: [0297] polyamide PA 11/10.T (0.7 mol of 11-aminocarboxylic
acid per mole of 1,10-decanediamine and terephthalic acid): 85.9%;
[0298] ethylene/ethyl acrylate/maleic anhydride copolymer (mass
ratio 69/30/1): 6%; [0299] ethylene/methyl acrylate/glycidyl
methacrylate copolymer (ratio 68/24/8): 3%; [0300] ethylene/butyl
acrylate/acrylic acid copolymer (ratio 88/8/4): 3%; [0301] heat
stabilizer composed of 80% KI, 10% CuI, and 10% calcium stearate:
0.7%; [0302] 4,4'-bis(alpha,alpha-dimethylbenzyl)diphenylamine
antioxidant: 0.5%; [0303] carbon black: 0.9%.
Vapor Compression Circuit Element
[0304] The composition of the invention described above is used as
a vapor compression circuit element.
[0305] A vapor compression circuit comprises at least one
evaporator, a compressor, a condenser, and an expander, and also
lines for transporting heat transfer fluid between these elements.
The evaporator and the condenser comprise a heat exchanger
permitting an exchange of heat between a heat transfer fluid, which
circulates within the circuit, and another fluid or body.
[0306] The installation may include a turbine for generating
electricity (Rankine cycle).
[0307] The vapor compression circuit may be integrated in an
installation which may possibly also comprise at least one heat
exchange fluid circuit used for transmitting heat (with or without
a change of state) between the heat transfer fluid circuit and the
fluid or body to be heated or cooled.
[0308] The installation may also possibly comprise two (or more)
vapor compression circuits, containing the same or different heat
transfer fluids. For example, the vapor compression circuits may be
coupled with one another.
[0309] The vapor compression circuit operates according to a
conventional vapor compression cycle. The cycle comprises the
change in state of the heat transfer fluid from a liquid phase (or
liquid/vapor biphase) to a vapor phase at a relatively low
pressure, then the compression of the vapor-phase fluid to a
relatively high pressure, the change in state (condensation) of the
heat transfer fluid from the vapor phase to the liquid phase at a
relatively high pressure, and the reduction of the pressure in
order to restart the cycle.
[0310] In the case of a cooling process, heat given off by the
fluid or the body which is being cooled (directly or indirectly,
via a heat exchange fluid) is absorbed by the heat transfer fluid,
in the evaporation of this fluid, at a temperature which is
relatively low in relation to the environment. Cooling processes
include air conditioning processes (with mobile installations, as
for example in vehicles, or with stationary installations),
refrigeration processes (with mobile installations, for example in
containers, or with stationary installations), and freezing or
cryogenic processes.
[0311] In the case of a heating process, heat is given up (directly
or indirectly, via a heat exchange fluid) from the heat transfer
fluid, in the condensation of the latter, to the fluid or body
which is being heated, at a relatively high temperature relative to
the environment. The installation which allows the transfer of heat
to be implemented is in this case called a "heat pump".
[0312] A "vapor compression circuit element", is understood to
mean, according to the present invention, any component of a
circuit of this kind, comprising a chamber, said component being
suitable for containing or transporting the heat transfer fluid.
The vapor compression circuit element that is the subject of the
present invention is preferably a pipe or tubing (or else a hose).
Alternatively the element in question may be a joining element or
connector between tubing or between tubing and compressor, or
condenser, or heat exchanger, or else a part of a buffer capacity
or a heat exchanger. The term "chamber" denotes the interior of
said component of said circuit, in particular the interior of the
pipe or of the tubing or the interior of the joining element or
connector.
[0313] The vapor compression circuit element may also be a heat
exchanger as such (in which case it comprises at least two chambers
for the circulation of two identical or different fluids, with one
necessarily giving up heat to the other).
[0314] The heat transfer fluid may be contained or transported in
gas, liquid, or bi-phase form in the above circuit element.
[0315] The layer of composition according to the invention
described above may in particular be a monolayer, or may be an
inner layer (intended to come into contact with the heat transfer
fluid) or an outer layer (intended to be in contact with the
environment) of the circuit element. This layer preferably
constitutes an inner layer (or coating).
[0316] Multilayer Tube
[0317] According to one particular embodiment, the vapor
compression circuit element according to the invention is a
flexible multilayer tube, intended in particular for a motor
vehicle air-conditioning installation. This tube may be intended,
for example, for connection at each end to metal tubing.
[0318] Preferably, and with reference to the FIGURE, the flexible
multilayer tube 10 comprises an inner layer 11 composed of the
composition of the invention described above, with the following
disposed in succession above said layer: optionally a first
intermediate layer 12, composed of a first composition comprising
an elastomeric material; optionally a second intermediate layer 13,
composed of a reinforcing textile; and an outer layer 14 composed
of a second composition comprising an elastomeric material.
[0319] A tube of this kind may be a "veneer" tube.
[0320] The first intermediate layer and/or the second intermediate
layer may be omitted when the outer elastomer layer is sufficiently
thick and/or when reinforcing fibers and/or fillers are included
therein.
[0321] It is also possible to provide an architecture wherein the
tube has a further layer of elastomeric material, in contact with
the inner layer (toward the chamber in the tube).
[0322] A tube of this kind may be a barrier tube.
[0323] The compositions comprising an elastomeric material may be
identical or different. The elastomeric material may comprise a
polymer selected from polyisoprenes, polybutadienes, copolymers of
butadiene and acrylonitrile, acrylic rubbers (AEM), epichlorohydrin
rubbers, copolymers of styrene and butadiene, butyl rubbers,
chlorinated butyl rubbers (CI-IIR), brominated butyl rubbers
(Br-IIR), chloroprene rubbers (CR), nitrile rubbers,
nitrile-butadiene rubbers (NBR), chlorosulfonated polyethylene
rubbers (CSM), ethylene-propylene copolymers, EPDMs
(ethylene-propylene-diene monomers),
ethylene-propylene-1,4-hexadiene terpolymers,
ethylene-propylene-dicyclopentadiene terpolymers, brominated
isobutylene-co-para-methylstyrenes (BIMS), and combinations
thereof. An elastomeric thermoplastic or a vulcanized thermoplastic
may be used.
[0324] Ethylene-propylene rubbers and EPDMs are preferred.
[0325] The reinforcing textile may be formed by braiding, knitting,
winding, or helical knitting of fibers. The fibers may be, for
example, glass, cotton, steel, polyester, or aramid fibers, or
combinations of these. The reinforcement provides pressure
resistance in combination with the layers of elastomeric
material.
[0326] The inner layer (composition of the invention) preferably
has a thickness of 25 to 250 .mu.m, and more preferably of 50 to
150 .mu.m.
[0327] The thickness of the other layers is adapted according to
the pressures used. It is possible, for example, for the assembly
of layers made of elastomeric material to be given a total
thickness of 1 to 10 mm. The thickness of the second intermediate
layer made of reinforcing textile is generally less than 1 mm.
Manufacture of the Composition of the Invention and of Circuit
Elements of the Invention
[0328] The composition of the invention may be prepared by any
method enabling a homogeneous mixture to be obtained, such as melt
extrusion, compacting, or roll milling.
[0329] More particularly, the composition of the invention may be
prepared by melt blending of the semi-aromatic polyamide(s), the
plasticizer(s), and the products (A), (B), and optionally (C)
producing the crosslinked polyolefin(s).
[0330] The optional additives and/or additional polymers may
themselves be introduced either at the same time as the
semi-aromatic polyamide(s), plasticizer(s), and products (A), (B),
and, where appropriate, (C), or in a subsequent step.
[0331] Advantageously, the composition may be obtained in the form
of pellets by compounding, in particular by means of a twin-screw
extruder, a co-kneader, or an internal mixer.
[0332] These pellets of the composition of the invention, obtained
by the above-described preparation process, may be subsequently
converted using tools known to the skilled person (such as an
injection press or an extruder), particularly in the form of tubes,
films, and/or moldings.
[0333] It is also possible to use a twin-screw extruder which
without intermediate pelletizing feeds an injection press or an
extruder, particularly for the production of tubes, films and/or
moldings.
[0334] The articles or objects according to the invention may be
obtained from the above composition by a known conversion process
such as injection molding, extrusion, extrusion-blow molding,
coextrusion, or multiple injection.
[0335] With regard to the manufacture of multilayer tubes described
in the preceding section, it is possible to use the following
method. [0336] The inner layer (composition of the invention) may
be extruded on a flexible or fixed mandrel. [0337] The first
intermediate layer (made of elastomeric material) is then applied.
[0338] The second intermediate layer (reinforcing textile) is then
applied. [0339] Subsequently the outer layer (made of elastomeric
material) is applied. Where appropriate, vulcanization is then
carried out in order to cure the elastomeric layers. [0340] There
is generally no need to use an adhesive between the layers, since
the assembly is provided with cohesion through fusional
bonding.
[0341] The resulting tubes may be cut before or after curing. If
they are cut before curing, the tube sections may be disposed on
short mandrels (which are curved, for example) before curing, in
order to give these tube sections a particular final shape or
configuration.
Heat Transfer Fluid
[0342] A "heat transfer compound" or "heat transfer fluid" (or
refrigerant or cold-generating fluid) is a compound or fluid,
respectively, that is capable of absorbing heat by evaporating at
low temperature and low pressure and of providing heat by
condensing at high temperature and high pressure, in a vapor
compression circuit. Generally speaking, a heat transfer fluid may
comprise one, two, three, or more than three heat transfer
compounds.
[0343] Moreover, the heat transfer fluid may optionally comprise
one or more additives which are not heat transfer compounds for the
intended application.
[0344] The heat transfer compounds may be hydrocarbon, ether,
hydrofluoroether, hydrofluorocarbons or fluoroolefin compounds or
HFO. Hydrofluorocarbons and fluoroolefins are preferred, and more
particularly fluoroolefins. Fluoropropenes, fluoropropanes, and
fluoroethanes are preferred.
[0345] Examples of preferred heat transfer compounds, used
individually or as a mixture, are 1,3,3,3-tetrafluoropropene
(R-1234ze), 2,3,3,3-tetrafluoropropene (R-1234yf),
1,2,3,3,3-pentafluoropropene (R-1225ye), 1,1,3,3-tetrafluoropropene
(R-1234zc), 3,3,3-trifluoropropene (R-1243zf),
2,3,3-trifluoropropene (R-1243yf), 1,1,1,2-tetrafluoroethane
(R-134a), 1,1,2,2-tetrafluoroethane (R-134), pentafluoroethane
(R-125), difluoromethane (R-32), 1,1-difluoroethane (R-152a),
1,1,1,2,3,3,3-heptafluoropropane (R-227ea), 1,1,1-trifluoropropane
(R-263), 1,1,1,3,3,3-hexafluoropropane (R-236fa),
1,1,1,3,3-pentafluoropropane (R-245fa), 1,1,1,3,3-penta
fluorobutane (R-365mfc), and trifluoroiodomethane.
[0346] The above compounds may also be used as a mixture with
ammonia or with carbon dioxide.
[0347] According to one preferred embodiment, the heat transfer
fluid is R-134a, or R-1234yf, the latter being particularly
preferred.
[0348] Mixtures of R-1234yf and ammonia, and of R-1234yf and carbon
dioxide, are also preferred, especially for stationary air
conditioning.
[0349] The additives may in particular be selected from lubricants,
nanoparticles, stabilizers, surfactants, tracers, fluorescers,
odorants, and solubilizers.
[0350] The stabilizer or stabilizers, when present, represent
preferably not more than 5% by mass in the heat transfer
composition. The stabilizers include in particular nitromethane,
ascorbic acid, terephthalic acid, azoles such as tolutriazole or
benzotriazole, phenolic compounds such as tocopherol, hydroquinone,
tert-butylhydroquinone, 2,6-di-tert-butyl-4-methylphenol, epoxides
(optionally fluorinated or perfluorinated alkyl, or alkenyl, or
aromatic) such as n-butyl glycidyl ether, hexanediol diglycidyl
ether, allyl glycidyl ether, butylphenyl glycidyl ether,
phosphites, phosphonates, thiols, and lactones.
[0351] Lubricants which can be used include, in particular, oils of
mineral origin, silicone oils, paraffins of natural origin,
naphthenes, synthetic paraffins, alkylbenzenes, poly-alpha-olefins,
polyalkylene glycols (PAG), polyol esters (POE) and/or polyvinyl
ethers.
[0352] According to the invention it is particularly preferred for
the heat transfer fluid circulating in the vapor compression
circuit to comprise a PAG lubricant or a POE lubricant.
[0353] According to one particularly preferred embodiment of the
invention, the heat transfer fluid is R-1234yf admixed with PAG
lubricant (and optionally further additives).
[0354] Among the PAG lubricants it is possible in particular to use
those described in document US 2010/0282999, hereby expressly
incorporated by reference. These lubricants conform to the formula
R.sub.1--(OR.sub.3).sub.n--R.sub.2, in which R.sub.1 and R.sub.2
are identical or different and represent a hydrogen atom, a C1-C5
alkyl group, or a C2-C5 acyl group, R.sub.3 represents a C2-C4
alkylene group, and the molar proportion of C2 alkylene groups in
the units R.sub.3 is not more than 30%. The hydroxyl value is
preferably not more than 100 mgKOH/g, or than 50, 30, or 10
mgKOH/g. The number-average molecular weight of the PAG is
preferably from 500 to 3000, or from 600 to 2000, or from 600 to
1500.
[0355] Among the PAG lubricants, it is also possible to use those
which are described in document US 2010/0175421, hereby expressly
incorporated by reference. These lubricants conform to the formula
R.sub.1--[(OR.sub.2).sub.m--R.sub.3].sub.n, in which R.sub.1
represents a hydrogen atom, a hydrocarbon group having 1 to 10
carbon atoms, an acyl group having 2 to 10 carbon atoms, a
hydrocarbon group having 2 to 6 bonding sites and 1 to 10 carbon
atoms, or a hydrocarbon group containing an oxygen atom and having
1 to 10 carbon atoms, R.sub.2 represents an alkylene group having 2
to 4 carbon atoms, R.sub.3 represents a hydrogen atom, a
hydrocarbon group having 1 to 10 carbon atoms, an acyl group having
2 to 10 carbon atoms, or a hydrocarbon group containing an oxygen
atom and having 1 to 10 carbon atoms, n represents an integer
ranging from 1 to 6, and m is a number such that the average value
m.times.n is from 6 to 80. Examples of such PAGs are polypropylene
glycol dimethyl ether, polyethylene-polypropylene glycol dimethyl
ether copolymer, polyethylene-polypropylene glycol methyl butyl
ether copolymer, and polypropylene glycol diacetate. The hydroxyl
value is preferably 5 mgKOH/g or less, or 3 mgKOH/g or less, or 1
mgKOH/g or less. The number-average molecular weight of the PAG is
preferably from 500 to 3000, or from 600 to 2500.
[0356] Among PAG lubricants, it is also possible to use those which
are described in document WO 2010/075046, hereby expressly
incorporated by reference. These lubricants conform to the formula
RX(R.sub.aO).sub.x(R.sub.bO).sub.yR.sub.c, in which R is selected
from alkyl groups having from 1 to 10 carbon atoms, aliphatic
hydrocarbon groups having from 2 to 6 valences, and substituents
comprising a heterocycle in which the heteroatom or heteroatoms is
or are oxygen, X is selected from O and S, R.sub.a is a C2 alkylene
group, R.sub.b is a C3 alkylene group, Re is identical to R or
represents H, and x and y are 0 or an integer less than or equal to
100, independently. The sum x+y is an integer ranging from 5 to
100. The aliphatic hydrocarbon groups include, in particular,
alkanes, alkenes, alkynes, and more particularly methyl, butyl, and
propyl groups. The lubricant may be a linear oxypropylene
homopolymer. Alkoxy terminations, and especially methoxy
terminations, are preferred. These lubricants have a kinematic
viscosity of preferably at least 30 cSt, or 20 cSt, or 10 cSt at
40.degree. C., or a viscosity index of at least 150, or 120 or 100.
The total acid value is preferably less than 0.03, or 0.02, or 0.01
mgKOH/g.
[0357] Nanoparticles which can be used include in particular carbon
nanoparticles, metal (copper, aluminum) oxides, TiO.sub.2,
Al.sub.2O.sub.3, MoS.sub.2, etc.
[0358] Tracers (capable of being detected) include deuterated or
non-deuterated hydrofluorocarbons, deuterated hydrocarbons,
perfluorocarbons, fluoroethers, brominated compounds, iodinated
compounds, alcohols, aldehydes, ketones, nitrous oxide, and
combinations thereof. The tracer is different from the heat
transfer compound or compounds constituting the heat transfer
fluid.
[0359] Solubilizers include hydrocarbons, dimethyl ether,
polyoxyalkylene ethers, amides, ketones, nitriles, chlorocarbons,
esters, lactones, aryl ethers, fluoroethers, and
1,1,1-trifluoroalkanes. The solubilizer is different from the heat
transfer compound or compounds constituting the heat transfer
fluid.
[0360] Fluorescers include naphthalimides, perylenes, coumarins,
anthracenes, phenanthracenes, xanthenes, thioxanthenes,
naphthoxanthenes, fluoresceins, and derivatives and combinations
thereof.
[0361] Odorants include alkyl acrylates, allyl acrylates, acrylic
acids, acrylic esters, alkyl ethers, alkyl esters, alkynes,
aldehydes, thiols, thioethers, disulfides, allyl isothiocyanates,
alkanoic acids, amines, norbornenes, norbornene derivatives,
cyclohexene, heterocyclic aromatic compounds, ascaridole,
o-methoxy(methyl)phenol, and combinations thereof.
[0362] With regard to motor vehicle air conditioning, preference is
given to using a single heat transfer compound (rather than a
mixture) and a single lubricant (rather than a mixture), for
reasons of stability within the vapor compression circuit.
EXAMPLES
[0363] The examples which follow illustrate the invention without
limiting it.
Example 1--General Evaluation of the Properties of the Internal
Lavers Accordinq to the Invention
[0364] In this example, a comparison is made between various
properties of a layer composed of a composition comprising a
copolyamide of formula X/10.T (according to the invention, molar
ratio from 0.5/1 to 0.7/1) with those of layers composed of known
compositions, namely: [0365] a layer composed of an impact-modified
PA 6 composition, corresponding to the product sold by DuPont under
the name Zytel.RTM. ST 811; [0366] a layer composed of an alloy of
PA 6 with crosslinked polyolefins (commercial branded product
Orgalloy.RTM. LT5050 Naturel from Arkema); [0367] a layer composed
of a PA 6.6/6.T composition; [0368] a layer composed of a PA 9.T or
PA 10.T composition (Genestar.RTM. N1001 D).
[0369] The results are reported in table 1 below. Each layer is
scored on a scale from 1 (lowest performance) to 10 (maximum
performance).
TABLE-US-00001 TABLE 1 Presentation of various properties PA
11/10.T PA PA 9.T or Orga- (inven- 6.6/6.T PA 10.T PA. 6 lloy .RTM.
tion) Barrier to 10 10 5 5 10 fluorinated refrigerants Dimensional
3 7 1 3 7 stability in association with water Water barrier 7 10 5
7 10 Thermal and 10 10 5 5 10 chemical stability (in the presence
of oil and R-134a refrigerant) Thermal and 5 5 3 3 5 chemical
stability (in the presence of oil and R-1234yf refrigerant)
Long-term thermal 5 7 1 3 10 stability Flexibility of 1 5 5 7 7
resulting tube Adhesion of the 3 3 7 7 5 layer to an elastomer
Shapeability 1 3 7 7 5 Total score 45 60 39 47 69
[0370] With regard to the evaluation of the barrier property with
respect to fluorinated refrigerants: a measurement of permeation
with respect to fluorinated refrigerants (see example 2) showed
that the class of semi-aromatic polyamides and copolyamides was a
significantly better barrier than the glass of the PA6 and
Orgalloy.RTM. products.
[0371] With regard to the evaluation of the dimensional stability
associated with water and of the water barrier: the absorption of
water (hence the dimensional variation) and the water permeation
into the polyamide materials are associated with the density of
amide functions. Accordingly, the polyamides of class PA 6 are the
most hydrophilic, followed by PA 6.6/6.T and Orgalloy.RTM., which
benefits, by comparison with PA 6, from the hydrophobic character
of the polyolefins incorporated, and, lastly, by PA 9.T, 10.T, and
the semi-aromatic copolyamides of the invention.
[0372] With regard to the evaluation of the thermal and chemical
stability (in the presence of oil and R-134a refrigerant): the data
for thermal stability (example 4) show that the aromatic polyamides
or copolyamides have a greater thermal stability than the class of
the PA 6 and Orgalloy.RTM. products.
[0373] The permeation data (example 2) show that the aromatic
polyamides or copolyamides have a greater barrier performance with
respect to R-134a than the class of the PA 6 and Orgalloy.RTM.
products.
[0374] With regard to the evaluation of the thermal and chemical
stability (in the presence of oil and R-1234yf refrigerant): the
data for thermal stability (example 4) show that the aromatic
polyamides or copolyamides have a greater thermal stability than
the class of the PA 6 and Orgalloy.RTM. products.
[0375] The permeation data (example 2) show that the aromatic
polyamides or copolyamides have a greater barrier performance with
respect to R-1234yf than the class of the PA 6 and Orgalloy.RTM.
products.
[0376] With regard to the evaluation of the long-term thermal
stability: the thermal stability data (example 4) show that the
aromatic polyamides or copolyamides have a greater thermal
stability than the class of PA 6 and Orgalloy.RTM. products.
[0377] With regard to the evaluation of the flexibility of the
resulting tube: the tensile modulus data (example 4) show that the
Orgalloy.RTM. products and aromatic copolyamides of the invention
are more flexible and therefore result in more flexible tubes at
the same thickness.
[0378] With regard to the evaluation of the adherence of the layer
to an elastomer: the adherence to elastomer becomes more difficult
as the melting temperature of the internal layer goes up (see
example 4).
[0379] With regard to the evaluation of the shapeability: the
greater the increase in the melting temperature (example 4), the
greater the shaping temperature, giving rise to an additional
energy cost.
Example 2--Properties of Permeability with Respect to Fluorinated
Refrigerants
[0380] In this example, the permeability with respect to
fluorinated refrigerants (R-1234yf and R-134a) having a layer
composed of a composition comprising a copolyamide of formula
X/10.T (according to the invention) is compared with that of layers
composed of known compositions, namely: [0381] a layer of
impact-modified PA 6, corresponding to the product sold by DuPont
under the name Zytel.RTM. ST 811, which constitutes a current
commercial reference for the internal layer of a veneer tube for
the transport of refrigerant in a motor vehicle air conditioning
circuit; [0382] a layer based on PA 6/6.6 copolymer, corresponding
to the product sold by Arkema under the name Rilsan.RTM. RDG113;
[0383] a layer based on PA 11 known for its high heat resistance,
sold by Arkema under the name Rilsan.RTM. BESN Noir P126TL; [0384]
a layer (according to the invention) composed of composition 1
described above; [0385] a layer (according to the invention)
composed of composition 2 described above.
[0386] The flow measurements were carried out with a permeation
cell, by Lyssy GPM500/GC coupling at a temperature of 23.degree. C.
and 0% relative humidity. The top face of the cell is swept with
the test gas, and the flow diffusing through the film in the lower
part is measured by gas chromatography. Helium is used as carrier
gas sweeping the lower part.
[0387] The results are reproduced in tables 2a and 2b below. The
thicknesses are expressed in .mu.m (mean thickness and standard
deviation); the flows of refrigerants are expressed in cm.sup.30.25
.mu.m/m.sup.2/24 h/atm. The density of the vapor phase of R-134a is
4.24 kg/m.sup.3, and the density of the vapor phase of R-1234yf is
37.6 kg/m.sup.3.
TABLE-US-00002 TABLE 2a Results for R-134a Thickness Flow DuPont
Zytel .RTM. ST 811 40 .+-. 8 0.02 Rilsan .RTM. RDG113 87 .+-. 6
0.04 Rilsan .RTM. BESN Noir P126TL 69 .+-. 4 12 Composition 1
(invention) 95 .+-. 5 <0.01
TABLE-US-00003 TABLE 2b Results for R-1234yf Thickness Flow DuPont
Zytel .RTM. ST 811 40 .+-. 8 0.02 Rilsan .RTM. BESN Noir P126TL 69
.+-. 4 3 Composition 2 (invention) 76 .+-. 7 <0.01
Example 3--Probabilities of Water Vapor Permeability
[0388] In this example, the permeability to water of a layer
composed of a composition comprising a semi-aromatic polyamide of
formula X/10.T (according to the invention, composition 2) is
compared with that of layers composed of known compositions, namely
a composition based on PA 11 (product Besno TL), a composition
based on PA 12 (product Aesno TL), an Orgalloy.RTM. composition
(R60ES), and a composition of stabilized PA 6.
[0389] The measurements are carried out according to standard ASTM
E96, method E. The flows in table 3 are given in g.25 .mu.m/24
h/m.sup.2.
[0390] The results are reported in table 3 below.
TABLE-US-00004 TABLE 3 Water permeation results Inven- Orga- PA 11
PA 12 tion lloy .RTM. PA 6 23.degree. C., 85% relative 28 25 28 17
50 humidity 85.degree. C., 85% relative 1600 1600 950 1600 1800
humidity
Example 4--Physical and Mechanical Properties
[0391] In this example, the typical melting temperature expressed
in .degree. C. (measured according to standard ISO 11357), the
typical (dry) tensile modulus expressed in MPa (measured according
to standard ISO 527), and the heat or temperature resistance for a
half-life of 1000 h (measured in accordance with the properties of
elongation at break according to standard ISO 527) are compared for
a polyamide PA 6.6/6.T, a polyphthalamide PA 9.T (Genestar.RTM.
N1001D), a polyamide PA 6 (stabilized), a polyamide from the
Orgalloy.RTM. range (LT 5050 Naturel), and a copolyamide according
to the invention (compositions 1 and 2).
[0392] The results are reported in table 4 below.
TABLE-US-00005 TABLE 4 Physical and mechanical results PA Orga-
Inven- 6.6/6.T PPA 9.T PA 6 lloy .RTM. tion Melting temperature
280-330 260-310 225 225 250-275 Tensile modulus 3500 2500 2500 700
500-1600 Heat resistance 145 145 135 140 160
[0393] It is clearly apparent from examples above that the
copolyamides of formula X/10.T/Y and in particular of formula
X/10.T have very satisfactory properties for them to be used as
inner layer in a tube in which an HFO refrigerant flows and
especially 1234yf in the presence of PAG oil.
* * * * *