FIELD

[0001] The field to which the disclosure generally relates is a hose suitable for use in refrigerant systems such as vehicle, industrial, and residential refrigerant systems, such as automotive air conditioning systems. The hose has an inner layer with improved properties used in air conditioning systems.

BACKGROUND

[0002] This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.

[0003] Hoses are used for transporting refrigerants in vehicle air conditioning (AC) systems, as well as industrial and residential refrigerant systems. Such hoses serve the purpose of joining the principal operating components of the refrigerating device. The hoses are typically designed to have good flexibility, high strength, the ability to bend to small radii without kinking, and to maintain impermeability to the fluids resident therein.

[0004] Recent changes in vehicle air conditioning systems necessitate changes to traditional compounds used in forming certain layers of vehicle air conditioning hoses, and in particular, the layer at the inner surface of the hose which is in contact with the refrigerant and compressor oil resident and contained within the hose. In one instance, the movement towards refrigerants with low global warming potentials (GWP) such as 2,3,3,3-tetrafluoropropene, known commercially as R1234yf, presents challenges in selecting materials for layers of the hose. Some traditional hose inner layers can decrease the effectiveness of these new refrigerants. Rubber materials with certain polymerization initiators including peroxides can lead to the polymerization of 2,3,3,3-tetrafluoropropene.

[0005] Additionally, with the hybridization and electrification of vehicles there has been a movement away from traditional polyalkylene glycol (PAG) AC system compressor oils to polyolester (POE) compressor oils, along with a demand for increased service temperatures. POE oils, however, can cause increased swelling and softening of traditional vehicle AC hose layer compounds, such as butyls, halobutyls, and chloroprenes. Furthermore, these traditional AC hose layer compounds may not be designed for use at increased service temperatures.

[0006] Another consideration is the emerging use of nickel in the automotive AC compressors. This requires avoidance of sulfur cure systems, sulfur donors, and other sulfur-containing accelerators and additives due to corrosion of nickel. Elemental sulfur can provide crosslinks that contain 3 to 8 sulfur atoms. These crosslinks have lower bond energy than the carbon to carbon bonds, and those crosslinks with the greatest the number of sulfur atoms will provide the weakest bonds strengths. These weaker sulfur to sulfur bonds, when exposed to heat or stress, create an opportunity for bond breakage. Any unreacted sulfur, along with this bond breakage could provide sulfur that could lead to sulfur corrosion in AC compressors when nickel and other materials with lower corrosion resistance are used. To reduce the number of sulfur crosslinks, the quantity of elemental sulfur can be reduced or eliminated and sulfur containing accelerators can be used. While the number of sulfur atoms within crosslinks will be reduced as compared to rubber conventionally cured with elemental sulfur, any sulfur-to-sulfur bonds will have more susceptibility to bond breakage than carbon-to-carbon bonds when exposed to heat or stress. Any unreacted portions of sulfur accelerators or sulfur donors will also be available to corrode easily corroded AC compressor components such as nickel. Typically, the need to avoid sulfur or the demand for increased service temperatures will drive material selection towards a peroxide cured elastomer, which presents issues described above.

[0007] Thus, there is an ongoing need for air conditioning hoses having certain layers constructed of material layers which overcome the issues described above, and such need is met, at least in part, with embodiments according to the following disclosure.

SUMMARY

[0008] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

In a first aspect of the disclosure, a refrigerant hose is provided, which includes an innermost tube defining a lumen therein, the innermost tube having an elastomeric material comprising a high temperature resistant polyepichlorohydrin (HT-ECO) rubber which is cured with a bis-phenol-S based curing system. The refrigerant hose may further, and optionally, include a permeation inhibiting layer which surrounds the innermost tube, and, optionally, an elastomeric tie layer. The refrigerant hose also includes a reinforcing layer disposed outwardly from the innermost tube and the optional permeation inhibiting layer, when used, as well as a cover layer disposed outwardly from the reinforcing layer. The innermost tube, in some cases, has a volume swell percentage of 10% or less when exposed to polyolester oil or polyalkylene glycol oil for 168 hourrs @ 150°C. Further, the innermost tube is devoid of peroxide, devoid of added reactive sulfur including elemental sulfur, and/or sulfur donors. In some aspects, the lumen contains molecules of 2,3,3,3-tetrafluoropropene refrigerant therein. In some cases, the bis-phenol-S based curing system includes sodium carbonate, bis-phenol-S and organo-onium.

[0009] According to some aspects, the refrigerant hose further includes a tie layer disposed between a permeation inhibiting layer and the reinforcing layer when a permeation barrier layer is incorporated into the refrigerant hose. In some cases, the cover layer is based on one or more of butyl (HR), halobutyl (CIIR/BIIR), high temperature resistant polyepichlorohydrin (HT-ECO) rubber which is cured with a bis- phenol-S based curing system, brominated isobutylene paramethyl-styrene (BIMS) and ethylene-propylene-diene monomer rubber (EPDM). The reinforcement layer may be a woven polyester fabric, such as a woven polyethylene terephthalate fabric, glass fibers, cotton fibers, polyester fibers, polyaramid fibers, and/or aramid fibers. In some aspects, the reinforcing layer is a spiral reinforcing layer, and the refrigerant hose further includes a second tie layer surrounding the spiral reinforcing layer, and a second spiral reinforcing layer disposed between the cover layer and the second tie layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and:

[0011] FIG. 1 illustrates a barrier braided hose in a cut away perspective view, in accordance with the disclosure;

[0012] FIG. 2 depicts an all rubber braided hose in a cut away perspective view, in accordance with the disclosure;

[0013] FIG 3 illustrates a spiral barrier hose in a cut away perspective view, in accordance with the disclosure;

[0014] FIG. 4 depicts a cross-section of a hose with refrigerant and oil contained therein.

DETAILED DESCRIPTION

[0015] The following description of the variations is merely illustrative in nature and is in no way intended to limit the scope of the disclosure, its application, or uses. The description is presented herein solely for the purpose of illustrating the various embodiments of the disclosure and should not be construed as a limitation to the scope and applicability of the disclosure. In the summary of the disclosure and this detailed description, each numerical value should be read once as modified by the term “about” (unless already expressly so modified), and then read again as not so modified unless otherwise indicated in context. Also, in the summary of the disclosure and this detailed description, it should be understood that a value range listed or described as being useful, suitable, or the like, is intended that any and every value within the range, including the end points, is to be considered as having been stated. For example, “a range of from 1 to 10” is to be read as indicating each and every possible number along the continuum between about 1 and about 10. Thus, even if specific data points within the range, or even no data points within the range, are explicitly identified or refer to only a few specific, it is to be understood that inventors appreciate and understand that any and all data points within the range are to be considered to have been specified, and that inventors had possession of the entire range and all points within the range.

[0016] Unless expressly stated to the contrary, "or" refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by anyone of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0017] In addition, use of the "a" or "an" are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of concepts according to the disclosure. This description should be read to include one or at least one and the singular also includes the plural unless otherwise stated.

[0018] The terminology and phraseology used herein is for descriptive purposes and should not be construed as limiting in scope. Language such as "including," "comprising," "having," "containing," or "involving," and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited.

[0019] Also, as used herein any references to "one embodiment" or "an embodiment" means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily referring to the same embodiment.

[0020] Hose embodiments according to the disclosure generally include a rubber hose having an innermost tube, at least one reinforcement layer, and an outer cover. The hose embodiments also include barrier style hose which generally includes a barrier layer, at least one reinforcement layer, optional reinforcement layer or layers, optional tie layer or layers, an outer cover, and an innermost tube.

[0021] The innermost tube, according to some aspects, is formed from an elastomeric material including a high temperature resistant polyepichlorohydrin (HT- ECO) rubber which is cured with a bis-phenol-S based curing system. Other suitable additives may also be included in a mixture forming the elastomeric material, such as, but not limited to, one or more carbon blacks, processing aids, antiozonants, retardants to prevent an unduly quick cure, curing aids, antioxidants, other reinforcing agents and fillers, such as silica, coupling agents, dispersants, adhesion promotors, and the like. After curing, the innermost tube has a volume swell percentage of 10% or less, a volume swell percentage in the range of 10% to 1 %, or even a volume swell percentage in the range of 7% to 1 %, when exposed to polyolester oil or polyalkylene glycol oil for 168 hours @ 150°C. Such properties provide lower volume swelling when in contact with polyolester oil as compared to typical air conditioning hose compounds. Also, lower hardness change is observed when using a high temperature resistant polyepichlorohydrin (HT-ECO) rubber which is cured with a bis-phenol-S based curing system, and the innermost tube in contact with polyolester oils, as compared to typical air conditioning hose compounds, while providing the improved temperature resistance as needed for some vehicles, such as hybrid and electric vehicles.

[0022] Any suitable high temperature resistant polyepichlorohydrin (HT-ECO) rubber may be used. Some nonlimiting examples include high temperature resistant polyepichlorohydrin (HT-ECO) rubbers from Zeon Chemicals L.P., Louisville, Ky, such as, but not limited to, Zeon Hydrin® HT-ECO DP5227. Any suitable bis-phenol-S, bisphenol AF or bis-penol Scoring system may be used for cuing the high temperature resistant polyepichlorohydrin (HT-ECO) rubber. Some nonlimiting examples include the Dynamar™ bis-phenol-SS based curing system available from Dyneon LLC of Oakdale, Minn. One non-limiting example of such a Dynamar™ system includes a combination of Dynamar™ RC5251 Q sodium carbonate cure activator, Dynamar™ FC5157 bis-phenol-S-S, and Dynamar™ FX5166 organo-onium.

[0023] It is observed by the inventors that by using a high temperature resistant polyepichlorohydrin (HT-ECO) rubber which is cured with a bis-phenol-SS based curing system for the innermost tube, the effectiveness of the refrigerant is improved by avoiding use of peroxide cure systems for the innermost tube, since residual peroxides can lead to the crosslinking of the refrigerant. It is observed by the inventors that by using such a high temperature resistant polyepichlorohydrin (HT-ECO) rubber which is cured with a bis-phenol-SS based curing system for the innermost tube, the compressor integrity is improved by avoiding the use of elemental or rubber maker's sulfur or sulfur donors which are known to corrode nickel in AC compressors.

[0024] With regards to the barrier layer, when used, any suitable material may be used to form the layer when constructing a barrier style hose. A barrier layer is not used in the all rubber construction. Some suitable, yet non-limiting examples of barrier materials includes polyamides such as PA11 , PA46, PA6, PA66, PA6,66, PA66,6, PA69, PA610, PA612, PA1010, PA1212, PA4T, PA6T, PA9T, and PA10T; thermoplastic polyester elastomers based upon polyether-ester block copolymers, such as those supplied under tradename Hytrel®; or thermoplastic elastomers comprised of polyamide and polyether backbone blocks, such as those supplied under tradename Pebax®.

[0025] When used, tie layer(s) is typically comprised of any suitable thermoset materials including, but not limited to, polybutadiene (BR), copolymers of butadiene and acrylonitrile (NBR), butyl rubber (HR), chlorobutyl rubber (CIIR), bromobutyl rubber (BUR), copolymers of butadiene and styrene (SBR), polychloroprene (CR), ethylene propylene rubber (EPM), or ethylene propene diene (EPDM) or blends of such materials such as, but not limited to, a BIIR/EPDM blend. In one embodiment, the base stock material for the layer is EPDM.

[0026] When used, the reinforcing layer may be based on a material formed by braiding, spiraling, knitting, or helical knitting of yarn. The reinforcing layer may be based on a material which is woven or non-woven. The material may be selected from conventional hose reinforcing yams, such as glass, cotton, polyester, or aramid fibers, or a blend of any of these fibers. In some aspects, the reinforcing layer in the hose is a polyester or aramid fabric, or even a blend of polyethylene terephthalate yam and polyethylene naphthalate yam to form the fabric.

[0027] Any suitable rubber may be used for the cover layer employed in embodiments of this disclosure. In some aspects, the rubber is selected from, but not limited to, ethylene propylene diene rubber (EPDM), ethylene propylene rubber (EPR), butyl rubber (HR), chlorobutyl rubber (CIIR), bromobutyl rubber (BUR), chloroprene rubber (CR), nitrile rubber (NBR), chlorosulfonated polyethylene rubber (CSM), epichlorohydrine rubber (ECO), high temperature resistance polyepichlorohydrine rubber (HT-ECO), acrylic rubber (ACM), chloroprene rubber (CR), ethylene-acrylic elastomer (AEM), or chlorinated polyethylene (CPE), and blends or copolymers thereof, and the like. In one embodiment, the base stock for the cover layer is EPDM.

[0028] With the exception of the innermost tube layer, the various material components utilized in the hose embodiments of this disclosure can be cured with conventional curatives including, but not limited to, peroxide, sulfur, sulfur donor curatives, amine curatives, resin cure system, metal oxide curatives, and the like. For example peroxides such as dicumyl peroxide, a-a-bis(t- butylperoxide)diisopropylbenzene, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, 1 , 1 -bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-bis(t- butylperoxy)hexane, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, and n-butyl 4,4- bis(t-butylperoxy)valerate can be employed in curing the rubber components of the hose. From 1 to about 10 parts of peroxide are generally utilized based on 100 parts of base polymer. Peroxides are preferred as the curative since they are less sensitive to premature crosslinking (scorch). Sulfur/sulfur donor curatives are also commonly used. A few examples of the many sulfur containing accelerators and sulfur donors available for rubber cure systems include tetramethyl thiuram disulfide, 4,4’- dithiodimorpholine, dipentamethylene thiuram tetrasulfide, thiocarbamyl sulfenamide, mercaptobenzothiazole, zinc dimethyl carbamate, dibenzothiazole disulfide, and N- cyclohexyl-2-benzothiazole sulfonamide.

[0029] The other rubber components employed in the hose of this invention can also contain various additives in conventional or suitable amounts. Such additives may include, and are not limited to retardants to prevent an unduly quick cure, antioxidants, processing aids, reinforcing agents and fillers, such as carbon black, silica, coupling agents, dispersants, adhesion promotors and the like.

[0030] Now referencing FIGS. 1 through 4 which depict some hose embodiments in accordance with the disclosure. FIG. 1 illustrates a barrier braided hose 100, in a cut away perspective view. Hose 100 includes an innermost tube 102, formed from an elastomeric material including a high temperature resistant polyepichlorohydrin (HT-ECO) rubber which is cured with a bis-phenol-SS based curing system, and which is surrounded by a permeation inhibiting layer 104. Disposed adjacent permeation inhibiting layer 104 is a tie layer 106 which has a reinforcing layer 108 disposed outwardly therefrom. Cover layer 110 is the outermost layer of hose 100.

[0031] With reference to FIG. 2, which depicts an all rubber braided hose 200, in a cut away perspective view, hose 200 includes an innermost layer 202, formed from an elastomeric material including a high temperature resistant polyepichlorohydrin (HT-ECO) rubber which is cured with a bis-phenol-S based curing system, and which surrounded by a reinforcing layer 208, and cover layer 210 is the outermost layer of hose 200.

[0032] Now referencing FIG. 3 which illustrates a spiral barrier hose 300, in a cut away perspective view. Hose 300 includes an innermost elastomer tube 302, formed from an elastomeric material including a high temperature resistant polyepichlorohydrin (HT-ECO) rubber which is cured with a bis-phenol-S based curing system, and which is surrounded by a permeation inhibiting layer 304. Adjacent to permeation inhibiting layer 304 is a tie layer 306 which has a spiral reinforcing layer 308 disposed outwardly therefrom. Surrounding the spiral reinforcing layer 308 is a second tie layer 312 which has second spiral reinforcing layer 314 disposed thereupon. Cover layer 310 is the outermost layer of hose 300.

[0033] Now referencing FIG. 4 which illustrates a cross-section of a barrier hose according to an embodiment of the disclosure with refrigerant and oil resident and contained therein. The cross-section is taken in a plane parallel the longitudinal centerline of the hose which is represented by + . Also, for purposes of illustrating the concept, as presented, this depiction presented is linearly dimensionless. Hose 400 includes an innermost tube 402, formed from an elastomeric material including a high temperature resistant polyepichlorohydrin (HT-ECO) rubber which is cured with a bis- phenol-S based curing system, and which, in some aspects, is surrounded by an optional permeation inhibiting layer 404, and disposed adjacent permeation inhibiting layer 404 is an optional tie layer 406. A reinforcing layer 408 disposed outwardly therefrom. Cover layer 410 is the outermost layer of hose 400. Resident within a lumen 412 defined within innermost tube 402 are molecules 420 of 2, 3,3,3- tetrafluoropropene refrigerant and POE oil droplets 422. As innermost tube 402 is formed from an elastomeric material including a high temperature resistant polyepichlorohydrin (HT-ECO) rubber which is cured with a bis-phenol-S based curing system, the 2,3,3,3-tetrafluoropropene refrigerant is stabilized, swelling due to contact of the inner wall of innermost tube 402 with POE oil is minimized, or essentially eliminated, and formation of polymerized 2,3,3,3-tetrafluoropropene molecules 424 is avoided. As such, innermost tube 402 is devoid of peroxide, as well as devoid of any added sulfur or sulfur containing materials, and lumen 412 is devoid of polymerized 2,3,3,3-tetrafluoropropene molecules 424.

EXAMPLE

[0034] Some embodiments of the disclosure illustrated by the following example that is merely for the purpose of illustration and is not to be regarded as limiting the scope of the disclosure, or the manner in which it can be practiced. Unless specifically indicated otherwise, parts (phr) are given by weight based upon the amount of epichlorohydrin (ECO) elastomer. In this experiment, the rubber formulation, to be used to for innermost layers of AC hoses, was prepared, cured and tested for physical properties indicated based on a formulation provided by Zeon Chemicals (HT-ECO Compounding March 2021.

[0035] Table 1 :

Ingredient Amount

Polyepichlorohydrin (HT-ECO) rubber 100

(High Temperature Resistant Hydrin)

N550 carbon black 45

Glycol ether adipate plasticizer 5

Aliphatic fatty acid ester processing aid 1

Stearic acid 1

Hydroquinoline antioxidant 2

Sodium carbonate cure activator 8 bis-phenol-S 1.25

Organo-onium 1

TOTAL 164.25

Viscosity Properties

Mooney Viscosity, ML(1+4) @ 100°C ML 1+4 49.8

Mooney Scorch, ML(1+30) @ 125°C

Minimum Viscosity 31.6

TS, (min) >30

T35, (min) >30 MDR-2000 Rheometer, 60min./160°C

ML, (dNm) 1.6

MH, (dN m) 16.5

Ts2, (min) 9.5

T'90, (min) 36.3

[0036] The cured rubber inner layer was determined to have the physical properties provided in Table 2.

[0037] Table 2:

Original Properties, Press Cured 45min./160°C

Post Cured 4hr/150°C

Hardness A, (pts) 72

Modulus @ 100 %, (MPa) 4.2

Tensile, (MPa) 16.8

Elongation, (%) 393

Tear Strength, Trouser, (N/mm) 8.4

After Air Oven Aging, 70hr/150°C

Hardness A, (pts) 79

Hardness Change A, (pts) 7

Tensile, (MPa) 16.1

Tensile Change, (%) -4

Elongation, (%) 312

Elongation Change, (%) -21

After Air Oven Aging, 168hr/150°C

Hardness A, (pts) 82

Hardness Change A, (pts) 10

Tensile, (MPa) 14.5

Tensile Change, (%) -14

Elongation, (%) 261

Elongation Change, (%) -34

After Oil Aging, I RM 901 , 168hr/150°C

Hardness A, (pts) 81

Hardness Change A, (pts) 9

Tensile, (MPa) 15.3

Tensile Change, (%) -9

Elongation, (%) 259

Elongation Change, (%) -34

Volume Change, (%) -4.5 After Oil Aging, IRM 903, 168hr/150°C

Hardness A, (pts) 76

Hardness Change A, (pts) 4

Tensile, (MPa) 119

Tensile Change, (%) -29

Elongation, (%) 212

Elongation Change, (%) -46

Volume Change, (%) 6.2

[0038] Table 3 - Immersion of typical Air Conditioning hose compounds at 125°C for 168 hours in POE compressor oil (polyolester):

[0039] Table 4 - Testing of typical Air Conditioning hose with construction including a HT-ECO inner layer:

[0040] The foregoing description of the embodiments has been provided for purposes of illustration and description. Example embodiments are provided so that this disclosure will be sufficiently thorough, and will convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the disclosure, but are not intended to be exhaustive or to limit the disclosure. It will be appreciated that it is within the scope of the disclosure that individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

[0041] Also, in some example embodiments, well-known processes, well- known device structures, and well-known technologies are not described in detail. Further, it will be readily apparent to those of skill in the art that in the design, manufacture, and operation of apparatus to achieve that described in the disclosure, variations in apparatus design, construction, condition, erosion of components, gaps between components may present, for example.

[0042] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0043] Spatially relative terms, such as "inner", “adjacent”, "outer," "beneath," "below," "lower," "above," "upper," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the example term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0044] Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims. [0045] List of Reference Numerals (part of the description)

100 Barner braided hose

200 All rubber hose

300 Spiral barrier hose

400 Hose

102, 202, 302, 402 Innermost tube

104, 304, 404 Permeation inhibiting layer

106, 306, 312, 406 Tie layer

108, 208, 408 Braided reinforcing layer

308, 314 Spiral reinforcing layer

110, 210, 310, 410 Cover layer

412 Lumen

420 Molecules of 2,3,3, 3-tetrafluoropropene refrigerant or 1 ,1 ,1 ,2-tetrafluoroethane refrigerant

422 POE or PAG oil droplets

424 Polymerized 2, 3, 3, 3-tetrafluoropropene