Hydraulic fluid composition based on polyalkylene glycol with enhanced fire resistance

Abstract

The present invention relates to a polar hydraulic fluid composition comprising a mixture of a polyalkylene glycol (PAG) obtained using a polymerization initiator having a carbon chain length of C4 to C18, a nonionic phosphate ester and an amine antioxidant, having enhanced fire resistance, and is a homopolymer and / or copolymer of ethylene oxide and / or butylene oxide and / or propylene oxide.

Description

Technical Field

[0001] The present invention relates to a polar hydraulic fluid composition, which comprises a mixture of polyalkylene glycol (PAG), nonionic phosphate ester and amine antioxidant, and has enhanced fire resistance, wherein the polyalkylene glycol (PAG) is obtained using a polymerization initiator with a carbon chain length of C4 to C18, and is a homopolymer and / or copolymer of ethylene oxide and / or butylene oxide and / or propylene oxide. Background Art

[0002] One of the challenges of today's technology is to develop hydraulic fluid compositions characterized by fire resistance, biodegradability and excellent practical properties, such as lubricity and stability during use. In addition, common factors affecting their application are economic considerations caused by the price of raw materials and the need for frequent fluid changes. The idea of ​​this article is to create products that meet the above technical and economic conditions, providing a usable and safe alternative for various applications and products based on mineral oils.

[0003] There are several classes of synthetic fire resistant hydraulic fluids available commercially, including HFDR fluids based on phosphate esters, HFC fluids based on water and glycols, and PAG fluids based on polyalkylene glycols.

[0004] HFDR features very good flame retardancy and thermal stability, but its high price and toxicity limit its use. In addition, due to long-term operation at high temperatures, they may show a tendency to hydrolyze, resulting in a decrease in lubrication performance and requiring more frequent oil changes.

[0005] HFC (water-glycol-based) oils are cheaper and safer, but their lubrication properties are generally poorer, especially at high temperatures. They also require special water retention systems, which increases operating costs.

[0006] PAG (polyalkylene glycol) oils, accordingly, are characterized by excellent thermal stability, good lubricity, biodegradability and enhanced fire resistance after addition of a suitable antioxidant, typically in excess of 1 wt / wt % of the hydraulic fluid composition.

[0007] The high levels of antioxidants used in WO 01 / 90232 A2 reduce the biodegradability of the formulation and lead to the inclusion of the product in the GHS (Globally Harmonized System of Classification and Labelling of Chemicals) classification. This classification includes the indication of hazards to human health and the environment in the safety data sheet of the final composition covered by the claims.

[0008] In the document WO 04 / 053031 A2, the use of highly ethoxylated polyalkylene glycols leads to an increase in the polarity of the liquid, which prevents one type of composition with enhanced fire resistance from being easily replaced by another type of composition. In addition, this makes the hygroscopicity of the liquid increased, interfering with its hydrolytic stability, resulting in the need for more frequent replacement of the liquid. The document also shows the possibility of using functional additives. The additives shown in the cited examples show strong toxicity to humans and the environment, making it difficult to use or even eliminating the possibility of use in the context of current laws and regulations.

[0009] Document US 6156228A shows hydraulic fluid compositions with enhanced fire resistance based on phosphoric acid esters and natural triglycerides, which may also contain polyalkylene glycols, which have a lower flash point than the subject of the present invention. Moreover, high contents of phosphoric acid esters can significantly reduce the hydrolytic stability. Summary of the invention

[0010] The subject of the present invention is a polar hydraulic fluid composition characterized by enhanced fire resistance. The hydraulic fluid composition comprises a mixture of polyalkylene glycols (PAGs) and additives in the form of phosphate esters and amine antioxidants, each additive and therefore each such composition being characterized by a kinematic viscosity at 40° C. of 41.4 mm 2 / s to 50.6mm 2 / s (ISO VG 46), which is what the end user expects.

[0011] In a first aspect, the present invention relates to a polar hydraulic fluid composition comprising:

[0012] a) at least one polyalkylene glycol (PAG) obtained using a polymerization initiator with a carbon chain length of C4 to C18, the polyalkylene glycol being a homopolymer and / or copolymer of 0% to 20% ethylene oxide on average molar content and / or 0% to 80% butylene oxide on average molar content and / or 20% to 100% propylene oxide on average molar content, the molecular weight of the polyalkylene glycol being 1000 Da to 1200 Da, and the kinematic viscosity at 40° C. being 41.4 mm 2 / s to 50.6mm 2 / s, in an amount ranging from 94.5% to 98.9% by weight relative to the total composition,

[0013] b) a nonionic phosphate ester, which is a reaction mass of tert-butylbenzene diphenyl phosphate and bis(tert-butylphenyl)phenyl phosphate, in an amount of 1 to 5 wt % relative to the total composition,

[0014] - an antioxidant, which is an aromatic amine, in an amount ranging from 0.1% to 0.5% by weight relative to the total composition,

[0015] The composition has a thickness of 41.4 mm as measured according to ISO 3448. 2 / s to 50.6mm 2 / s kinematic viscosity at 40°C (viscosity grade ISO VG 46),

[0016] and a flash point greater than 270°C as determined according to ASTM D92.

[0017] Preferably, the polar hydraulic fluid composition has a viscosity greater than 47.5 mm as measured according to ASTM D445. 2 / s kinematic viscosity at 40°C.

[0018] Preferably, the composition has a biodegradability greater than 65% as determined according to OECD 301F.

[0019] Preferably, the composition comprises two polyalkylene glycols, wherein the first polyalkylene glycol is obtained using a polymerization initiator having a carbon chain length of C4, and the second polyalkylene glycol is obtained using a polymerization initiator having a carbon chain length of C16 to C18.

[0020] Preferably, in the polar hydraulic fluid composition, the first polyalkylene glycol has a mass of 1000 Da to 1099 Da, and the second polyalkylene glycol has a mass of 1100 Da to 1200 Da.

[0021] The composition of the present invention adopts another way to ensure the realization of the non-classification effect; that is, the product has a small impact on the natural environment, is safe to use, and does not harm human health, safety and the environment; due to the use of only safe raw materials and high biodegradability confirmed by the OECD 301F test, high ignition resistance is achieved at the same time.

[0022] The invention described is a hydraulic fluid composition consisting of a mixture of PAG (polyalkylene glycol) and purified non-toxic phosphate esters, wherein the amount of phosphate esters allows to increase the fire resistance, wherein the composition consists of biodegradable raw materials (more than 80%), the amount of ester introduced (up to 5% by weight) has no significant impact on the economics of the product. The composition also contains an antioxidant, however, the amount of antioxidant does not affect the classification of the product (up to 0.5% by weight).

[0023] The term "hydraulic fluid" refers to hydraulic oil, also called base oil or hydraulic oil or hydraulic preparation, which includes all agents used to transmit loads in hydraulic systems. Polar hydraulic fluid refers to hydraulic fluid compositions that exhibit the characteristics of polar molecules due to the chemical structure of their components, in particular the presence of hydroxyl groups in their structure, while non-polar hydraulic fluid refers to hydraulic fluid compositions that do not exhibit the characteristics of polar molecules due to the chemical structure of their components, which is related to the absence of hydroxyl groups or other polar groups in their chemical structure.

[0024] The polyalkylene glycol (PAG) is obtained using a polymerization initiator with a carbon chain length of C4 to C18. The polyalkylene glycol forming the basis of the hydraulic fluid composition is a homopolymer and / or copolymer of ethylene oxide (EO) and / or butylene oxide (BO) and / or propylene oxide (PO), wherein the average molar content of EO is 0% to 20%, the average molar content of BO is 0% to 80%, and the average molar content of PO is 20% to 100%. In addition, the composition according to the invention has an optimized C:O atomic ratio - according to literature data, when the ratio of carbon atoms to oxygen atoms is less than 3 or equal to 3, the PAG type base oil is insoluble in mineral oil (Synthetics, Mineral Oils, and Bio-Based Lubricants: Chemistry and Technology, Second Edition, Editor: Leslie R. Rudnick, Publisher: CRC Press, 2013; ISBN1439855374, 9781439855379), which ensures high biodegradability (higher than 65%) while being compatible / miscible with non-polar hydraulic fluids (base oils). The composition parameters of the polyalkylene glycols are average values, which is due to the fact that, firstly, they are produced from reactants of an inaccurately determined composition, or, secondly, they are mixtures of several polyalkylene glycols, whose final parameters are the arithmetic averages of the base PAGs constituting the mixture. The composition according to the invention may contain one or more than one polyalkylene glycol.

[0025] Phosphate is an alkyl derivative or an aryl derivative of phosphoric acid (V), which may include tri(p-tert-butylphenyl) phosphate, bis(p-tert-butylphenyl) phenyl phosphate and p-tert-butylphenyl diphenyl phosphate. Preferably, the phosphate constituting the base additive in the composition is a reaction mass (product of the same reaction) of tert-butylphenyl diphenyl phosphate and bis(tert-butylphenyl) phenyl phosphate.

[0026] The hydraulic fluid composition is composed of unclassified raw materials, so the product has little impact on the natural environment and is safe to use. Unclassified products are those that do not show any hazards to human health, safety and the environment in the safety data sheet.

[0027] At the same time, the hydraulic fluid composition provides better operating properties compared to typical products consisting of non-polar oils (mineral oils) (Table 1). In addition, the composition meets the requirements of the PN-EN ISO 12922 standard for hydraulic fluids.

[0028] Unexpectedly, the combination of a selected polyalkylene glycol, a mixture of additives in the form of phosphates and antioxidant amines can synergistically form a hydraulic fluid composition having very good industrial application parameters, as well as enhanced fire resistance.

[0029] Advantages of the Invention

[0030] Enhanced Fire Resistance:

[0031] The subject matter of the present invention is characterized by an increased flash point compared to other non-polar hydraulic oils and polyalkylene glycol type base oils of the same viscosity grade (Table 1). In addition, the developed composition is naturally non-flammable, which reduces the risk of fire in industrial applications where high temperatures or open fire sources are present.

[0032] Biodegradable and Environmentally Friendly:

[0033] The hydraulic fluid composition of the present invention is non-toxic and biodegradable, which makes it more environmentally friendly compared to non-polar hydraulic fluids. All ingredients of the hydraulic fluid composition are unclassified and are characterized by high biodegradability (Table 1).

[0034] Compatibility with non-polar hydraulic fluids:

[0035] The hydraulic fluid composition contains polyalkylene glycol synthesized using an optimal composition of C4 to C18 alcohol and alkylene oxide, and ensures high compatibility with polar hydraulic fluids and non-polar hydraulic fluids due to the optimized C:O ratio (according to literature data, when the ratio of carbon atoms to oxygen atoms is less than 3 or equal to 3, the PAG base oil is insoluble in mineral oil (Synthetics, Mineral Oils, and Bio-Based Lubricants: Chemistry and Technology, Second Edition, Editor: Leslie R. Rudnick, Publisher CRC Press, 2013; ISBN1439855374, 9781439855379)) (Table 2).

[0036] The polar-nonpolar nature also provides a wider range of additive options.

[0037] Excellent lubrication performance:

[0038] Compared to non-polar hydraulic fluids, the hydraulic fluid composition provides excellent lubrication properties while ensuring the above parameters (Table 1). The optimized composition reduces friction and wear of components, which translates into a longer service life of hydraulic systems such as pumps or actuators.

[0039] Material Compatibility:

[0040] The subject matter of the present invention is compatible with a wide range of elastomers (NBR-Nitrile rubber, FKM-Fluororubber, EPDM-Ethylenepropylene diene monomer) and metals used in hydraulic systems, thereby reducing the risk of degradation of seals, hydraulic hoses and other components (Table 1).

[0041] These advantages make the present invention an ideal solution for demanding industrial applications where safety, efficiency and environmental protection are critical.

[0042] Summarize

[0043] - The components of the composition are unclassified raw materials, which ensures minimal impact on the natural environment and safety in use.

[0044] - Blends of polyalkylene glycols of different media compositions offer improved properties for a variety of applications, including better thermal stability and higher compatibility with elastomers and metals used in hydraulic systems.

[0045] - This composition enables products based on non-polar oils (mineral, esters) to be easily replaced by the composition that is the subject of the invention, without the need to clean the hydraulic system.

[0046] - The composition is characterized by better thermal stability compared to existing hydraulic fluids.

[0047] - The proportion of polyalkylene glycol (PAG) in the composition improves its lubricating properties compared to conventional hydraulic fluids. DETAILED DESCRIPTION

[0048] The subject of the present invention is a polar hydraulic fluid composition characterized by enhanced fire resistance.

[0049] The hydraulic fluid composition of the present invention comprises:

[0050] - A mixture of polyalkylene glycols (PAGs) in an amount higher than 90% by weight relative to the total composition, preferably from 94.5% to 98.9%, obtained using polymerization initiators with carbon chain lengths ranging from C4 to C18. The polyalkylene glycols forming the basis of the hydraulic fluid composition are homopolymers and / or copolymers of ethylene oxide and / or butylene oxide and / or propylene oxide. The polyalkylene glycols form the basis of the hydraulic fluid composition, conferring its essential characteristics, including non-flammability, biodegradability, lubricity.

[0051] - Ashless anti-wear (AW) additives such as non-ionic phosphates in an amount of 1 to 5 wt% relative to the total composition, preferably a reaction mass of tert-butylbenzene diphenyl phosphate and bis(tert-butylphenyl)phenyl phosphate, which can enhance fire resistance and prevent wear of hydraulic parts such as pumps and cylinders.

[0052] - Antioxidant additives such as amine antioxidants, in an amount ranging from 0.1% to 0.5% by weight relative to the total composition, which additives help to limit oxidative degradation of the fluid when operating at high temperatures. Example

[0053] Example 1

[0054] The composition comprises:

[0055] - Polyalkylene glycol with a molecular weight of 1050Da, starting from C4 alcohol, is a propylene oxide (PO) homopolymer with 17 to 18 PO units and a kinematic viscosity of 41.4mm at 40°C 2 / s to 50.6mm 2 / s (ISO VG 46), the amount thereof being 50% by weight relative to the total composition.

[0056] - Polyalkylene glycol with a molecular weight of 1100Da, starting from C18 alcohol, is a propylene oxide (PO) homopolymer with 14 to 15 PO units and a kinematic viscosity of 41.4mm at 40°C 2 / s to 50.6mm 2 / s (ISO VG 46), the amount of which is 45% by weight relative to the total composition.

[0057] - The kinematic viscosity of the reaction mass of tert-butylbenzene diphenyl phosphate and bis(tert-butylphenyl)phenyl phosphate (product of the same reaction) at 40°C is 41.4 mm 2 / s to 50.6mm 2 / s (ISO VG 46) of Rokolub AD 246 ULTRA in an amount of 4.8% by weight, relative to the total composition.

[0058] - N-[(1,1,3,3-tetramethylbutyl)phenyl]naphthalen-1-amine in an amount of 0.2% by weight relative to the total composition.

[0059] Example 2

[0060] The composition comprises:

[0061] - Polyalkylene glycol with a molecular weight of 1075Da, starting from C4 alcohol, is a copolymer of propylene oxide (PO) and ethylene oxide (EO), with 14 to 15 PO units, 4 to 5 EO units, PO:EO ratio of 4:1, and a kinematic viscosity of 41.4mm at 40°C 2 / s to 50.6mm 2 / s (ISO VG 46), the amount of which is 40% by weight relative to the total composition.

[0062] - Polyalkylene glycol with a molecular weight of 1100Da, starting from C18 alcohol, is a propylene oxide (PO) homopolymer with 14 to 15 PO units and a kinematic viscosity of 41.4mm at 40°C 2 / s to 50.6mm 2 / s (ISO VG 46), the amount of which is 56% by weight relative to the total composition.

[0063] - The kinematic viscosity of the reaction mass of tert-butylbenzene diphenyl phosphate and bis(tert-butylphenyl)phenyl phosphate (product of the same reaction) at 40°C is 41.4 mm 2 / s to 50.6mm 2 / s (ISO VG 46) of Rokolub AD 246 ULTRA in an amount of 3.7% by weight, relative to the total composition.

[0064] - N-[(1,1,3,3-tetramethylbutyl)phenyl]naphthalen-1-amine in an amount of 0.3% by weight relative to the total composition.

[0065] Example 3

[0066] The composition comprises:

[0067] - Polyalkylene glycol with a molecular weight of 1050Da, starting from C4 alcohol, is a propylene oxide (PO) homopolymer with 17 to 18 PO units and a kinematic viscosity of 41.4mm at 40°C 2 / s to 50.6mm 2 / s (ISO VG 46), the amount of which is 60% by weight relative to the total composition.

[0068] - Polyalkylene glycol with a molecular weight of 1150Da, starting from C18 alcohol, is a copolymer of propylene oxide (PO) and butylene oxide (BO), with 6 to 7 PO units, 6 to 7 BO units, PO:BO ratio of 1:1, and a kinematic viscosity of 41.4mm at 40°C 2 / s to 50.6mm 2 / s (ISO VG 46), the amount of which is 36% by weight relative to the total composition.

[0069] - The kinematic viscosity of the reaction mass of tert-butylbenzene diphenyl phosphate and bis(tert-butylphenyl)phenyl phosphate (product of the same reaction) at 40°C is 41.4 mm 2 / s to 50.6 mm 2 / s (ISO VG 46) of Rokolub AD 246ULTRA, the amount of which accounts for 3.6% by weight of the total composition.

[0070] - N-[(1,1,3,3-tetramethylbutyl)phenyl]naphthalen-1-amine in an amount of 0.4% by weight relative to the total composition.

[0071] The term "within the range" in relation to the number of alkylene oxide units, or in the case of alcohols as starting materials, to the number of carbon atoms, results from the nature of the ingredients used in the composition according to the invention. The polyalkylene glycol used in the composition according to the invention is a polymeric compound and is therefore in fact a mixture of polymers of similar structure, but differing in the content of the groups described within certain narrow limits. It is therefore difficult to give a precise quantitative composition in the case of ingredients of this type.

[0072] The molecular weight of the polyalkylene glycol of the present invention is about 1000 Da to about 1200 Da, preferably about 1050 Da to about 1150 Da. The molecular weight is determined by gel permeation chromatography (GPC).

[0073] Table 1 below gives the parameters and properties of the compositions according to the invention (1 to 3) and compares them with commercial products (4 to 7).

[0074] Table 1

[0075]

[0076] Sample 1 - Composition 1 according to the invention

[0077] Sample 2 - Composition 2 according to the invention

[0078] Sample 3 - Composition 3 according to the invention

[0079] Sample 4 - L-HV type hydraulic mineral oil, composed of >90% hydrogenated heavy paraffin fraction (petroleum), kinematic viscosity at 40°C is about 40 mm 2 / s, is a mixture of API Group I base oil, i.e., SN150 and SN500, and 0.1% 2,6-di-tert-butylphenol.

[0080] Sample 5 - PAO-based HEPR type flame retardant synthetic hydraulic oil, composed of >90% polyalphaolefin, hydrogenated polydecene, with a kinematic viscosity of about 46 mm at 40°C 2 / s.

[0081] Sample 6 - a flame retardant synthetic hydraulic oil based on HFDR type phosphate esters, marketed as Rokolub FR T-46, consisting of 100% of the reaction mass of tert-butylbenzene diphenyl phosphate and bis(tert-butylphenyl)phenyl phosphate.

[0082] Sample 7 - Base oil Group V PAG type, trade name Rokolub PB-46, composed of >99% propoxylated butanol, molecular weight of 1050 Da, number of PO units of 17 to 18.

[0083] Table 2 below shows the compatibility comparison of the composition according to the present invention with standard solutions etc. The symbols in Table 1 are valid.

[0084] Table 2

[0085]

Claims

1. A polar hydraulic fluid composition comprising: a) at least one polyalkylene glycol (PAG) obtained using a polymerization initiator with a carbon chain length of C4 to C18, the polyalkylene glycol being a homopolymer and / or copolymer with an average molar content of 0 to 20% of ethylene oxide and / or an average molar content of 0 to 80% of butylene oxide and / or an average molar content of 20 to 100% of propylene oxide, the molecular weight of the polyalkylene glycol being 1000 to 1200 Da and the kinematic viscosity at 40° C. being 41.4 mm 2 / s to 50.6mm 2 / s, and the amount of the polyalkylene glycol is 94.5 wt % to 98.9 wt % relative to the total composition, b) a nonionic phosphate ester, which is a reaction material of tert-butylbenzene diphenyl phosphate and bis(tert-butylphenyl)phenyl phosphate, wherein the amount of the nonionic phosphate ester is 1 wt % to 5 wt % relative to the total composition, - an antioxidant which is an aromatic amine, the amount of said antioxidant being from 0.1% to 0.5% by weight relative to the total composition, in, The composition has a thickness of 41.4 mm as measured according to ISO 3448. 2 / s to 50.6mm 2 / s (viscosity grade ISO VG46) at 40°C, and a flash point greater than 270°C as determined according to ASTM D92.

2. The polar hydraulic fluid composition of claim 1, wherein the composition has a viscosity greater than 47.5 mm as measured according to ASTM D445. 2 / s kinematic viscosity at 40°C.

3. The polar hydraulic fluid composition of claim 1 or 2, wherein the composition has a biodegradability greater than 65% as determined according to OECD 301F.

4. The polar hydraulic fluid composition according to any one of claims 1 to 3, wherein: The composition comprises two polyalkylene glycols, a first polyalkylene glycol is obtained using a polymerization initiator having a carbon chain length of C4, and a second polyalkylene glycol is obtained using a polymerization initiator having a carbon chain length of C16 to C18.

5. The polar hydraulic fluid composition of claim 4, wherein the mass of the first polyalkylene glycol is from 1000 Da to 1099 Da, and the mass of the second polyalkylene glycol is from 1100 Da to 1200 Da.

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