Thermoplastic resin composition for coolant transport lines and coolant transport pipe

Abstract

Thermoplastic resin composition for a coolant transport line, comprising a matrix containing a thermoplastic resin and a rubber domain dispersed in the matrix, wherein the thermoplastic resin composition has an oxygen permeability coefficient of not greater than 0.02 cm³·mm / (m²·day·mmHg) at a temperature of 21°C and at a relative humidity of 0%, the thermoplastic resin forming the matrix has a melt viscosity of not greater than 300 Pa·s at a temperature of 250°C and a shear rate of 243.2 s⁻¹, the thermoplastic resin comprises a thermoplastic resin with a melting point or glass transition point of not less than 150°C and with an oxygen permeability coefficient of not greater than 0.004 cm³·mm / (m²·day·mmHg) at a temperature of 21°C and at a relative humidity of 0%, the thermoplastic resin at least oneselected from the group consisting of a polyamide, a polyester, an ethylene-vinyl alcohol copolymer, a polycarbonate and a polyketone, the rubber is an isobutylene-based block copolymer comprising a polyisobutylene block and a polystyrene block, and an olefin-based or styrene-based polymer with at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, an acid anhydride group and a carboxyl group, and the thermoplastic resin composition comprises the matrix at a volume ratio of 25 to 50 vol% and the domain at a volume ratio of 50 to 75 vol%.

Description

AREA

[0001] The present invention relates to a thermoplastic resin composition for a coolant transport line and a coolant transport line. In particular, the present invention relates to a thermoplastic resin composition for a coolant transport line, comprising a matrix comprising a thermoplastic resin and a rubber domain dispersed in the matrix, as well as a coolant transport line comprising a layer of the thermoplastic resin composition. BACKGROUND

[0002] For motor vehicles, there is an increasing need for weight reduction, and efforts are underway to achieve this by manufacturing hoses from resins with good barrier properties instead of the rubber hoses traditionally used in motor vehicles, thus reducing their thickness. In particular, hoses for refrigerant transport in air conditioning systems of common motor vehicles are mainly made of rubber materials, and if these primary materials can be replaced by resins with good barrier properties, weight reduction can be achieved.

[0003] ZB proposes, as a hose for transporting a coolant, such as Freon gas, a hose comprising an inner liner, a reinforcing layer and an outer liner, wherein an inner layer of the inner liner is formed from a polyamide-based resin, an outer layer of the inner liner is formed from a polyamide / acrylic rubber graft polymer alloy or a thermoplastic elastomer comprising a thermoplastic polyolefin resin and EPDM, butyl-based rubber or acrylonitrile butadiene rubber, and the outer liner is formed from a thermoplastic elastomer comprising a thermoplastic polyolefin resin and EPDM or butyl-based rubber. [QUOTATION LIST][PATENT LITERATURE]

[0004] [Patent Literature 1] Japanese Unexamined Patent Publication No. H4-145284 SUMMARY [TECHNICAL TASK]

[0005] The resin material of the inner layer of the inner conduit forming the tube of patent literature 1, although good in terms of barrier properties, lacks flexibility, and the resin material of the outer layer of the inner conduit and the resin material of the outer conduit forming the tube, although excellent in terms of flexibility, are not necessarily satisfactory in terms of extrusion processability.

[0006] An objective of the present invention is to provide a thermoplastic resin composition for a coolant transport line, wherein the composition is good with regard to barrier properties, is flexible and is advantageous with regard to extrusion processability. [SOLUTION TO THE TASK]

[0007] The present invention (I) provides a thermoplastic resin composition for a coolant transport line, comprising a matrix comprising a thermoplastic resin and a domain comprising a rubber dispersed in the matrix, wherein the thermoplastic resin composition has an oxygen permeability coefficient of 0.02 cm 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and at a relative humidity of 0%, the thermoplastic resin forming the matrix has a melt viscosity of not greater than 300 Pa·s at a temperature of 250°C and at a shear rate of 243.2 s -1 exhibits that the thermoplastic resin is a thermoplastic resin with a melting point or glass transition point of not less than 150°C and a thermoplastic resin with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2·day·mmHg) at a temperature of 21°C and at a relative humidity of 0% or a thermoplastic resin with a melting point or glass transition point of not less than 150°C and with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and a relative humidity of 0%, and the rubber comprises an isobutylene-based block copolymer comprising a polyisobutylene block and a polystyrene block, and an olefin-based or styrene-based polymer with at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, an acid anhydride group and a carboxyl group.

[0008] The present invention (II) provides a coolant transport line comprising a layer of the thermoplastic resin composition according to the present invention (I) as an inner layer.

[0009] The present invention includes the following aspects. [1] Thermoplastic resin composition for a coolant transport line, comprising a matrix comprising a thermoplastic resin and a rubber domain dispersed in the matrix, wherein the thermoplastic resin composition has an oxygen permeability coefficient of not greater than 0.02 cm 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and at a relative humidity of 0%, wherein the thermoplastic resin forming the matrix has a melt viscosity of not greater than 300 Pa·s at a temperature of 250°C and a shear rate of 243.2 s -1exhibits that the thermoplastic resin is a thermoplastic resin with a melting point or a glass transition point of not less than 150°C and a thermoplastic resin with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and at a relative humidity of 0% or a thermoplastic resin with a melting point or glass transition point of not less than 150°C and with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2·day·mmHg) at a temperature of 21°C and at a relative humidity of 0%, and the rubber comprises an isobutylene-based block copolymer comprising a polyisobutylene block and a polystyrene block, and an olefin-based or styrene-based polymer with at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, an acid anhydride group and a carboxyl group. [2] Thermoplastic resin composition for a coolant transport line according to [1], wherein the thermoplastic resin composition has a 10% modulus of not greater than 10 MPa at a temperature of 25°C and at a relative humidity of 50% in a tensile test according to JIS K7161. [3] Thermoplastic resin composition for a coolant transport line according to [1] or [2], wherein the thermoplastic resin is at least one selected from the group consisting of a polyamide, a polyester, an ethylene vinyl alcohol copolymer, a polycarbonate and a polyketone. [4] Thermoplastic resin composition for a coolant transport line according to one of [1] to [3], wherein the isobutylene-based block copolymer comprises a styrene-isobutylene diblock copolymer and / or a styrene-isobutylene-styrene triblock copolymer. [5] Thermoplastic resin composition for a coolant transport line according to one of [1] to [4], wherein the olefin-based or styrene-based polymer is at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, an acid anhydride group and a carboxyl group, and at least one selected from the group consisting of an acid anhydride-modified α-olefin-based thermoplastic elastomer, an acid anhydride-modified styrene-ethylene-butylene-styrene block copolymer, an acid anhydride-modified styrene-ethylene-propylene-styrene block copolymer and an acid anhydride-modified ethylene-ethyl acrylate copolymer. [6] Thermoplastic resin composition for a coolant transport line according to one of [1] to [5], wherein the thermoplastic resin composition comprises the matrix at a volume ratio of 25 to 50 vol% and the domain at a volume ratio of 50 to 75 vol%. [7] Thermoplastic resin composition for a coolant transport line according to one of [1] to [6], wherein the proportion of the total amount of thermoplastic resin has a melting point or glass transition point of not less than 150°C, and the proportion of thermoplastic resin has an oxygen permeability coefficient of not greater than 0.04 cm 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and at a relative humidity of 0% and of the thermoplastic resin with a melting point or a glass transition point of 150°C or more and with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2·day·mmHg) at a temperature of 21°C and at a relative humidity of 0% in the matrix is ​​not less than 50 wt%. [8] Thermoplastic resin composition for a coolant transport line according to one of [1] to [7], wherein the proportion of the isobutylene-based block copolymer in the domain is 50 to 95 wt.%. [9] Thermoplastic resin composition for a coolant transport line according to one of [1] to [8], wherein the thermoplastic resin composition comprises 0.5 to 5 parts by weight of at least one selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester and a fatty acid amide, based on 100 parts by weight of the rubber in the thermoplastic resin composition.

[10] Thermoplastic resin composition for a coolant transport line according to one of [1] to [9], wherein the thermoplastic resin composition comprises 0.5 to 10 parts by weight of a divalent metal oxide, based on 100 parts by weight of the rubber in the thermoplastic resin composition.

[11] Thermoplastic resin composition for a coolant transport line according to one of [1] to

[10] , wherein the thermoplastic resin composition comprises 0.1 to 8 parts by weight of a trihydric alcohol having a triazine backbone, based on 100 parts by weight of the rubber in the thermoplastic resin composition.

[12] Coolant transport line comprising a layer of the thermoplastic resin composition according to one of [1] to

[11] as an inner layer. [BENEFICIAL EFFECTS OF THE INVENTION]

[0010] The thermoplastic resin composition according to the invention for a coolant transport line is good in terms of barrier properties, flexible and advantageous in terms of extrusion processability. DESCRIPTION OF THE EXECUTION FORMS

[0011] The present invention (I) provides a thermoplastic resin composition for a coolant transport line, comprising a matrix comprising a thermoplastic resin and a rubber domain dispersed in the matrix, wherein the thermoplastic resin composition has an oxygen permeability coefficient of not greater than 0.02 cm 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and at a relative humidity of 0%, the thermoplastic resin forming the matrix has a melt viscosity of not greater than 300 Pa·s at a temperature of 250°C and at a shear rate of 243.2 s -1exhibits that the thermoplastic resin is a thermoplastic resin with a melting point or glass transition point of not less than 150°C and a thermoplastic resin with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and at a relative humidity of 0% or a thermoplastic resin with a melting point or glass transition point of not less than 150°C and with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2·day·mmHg) at a temperature of 21°C and a relative humidity of 0%, and the rubber comprises an isobutylene-based block copolymer comprising a polyisobutylene block and a polystyrene block, and an olefin-based or styrene-based polymer with at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, an acid anhydride group and a carboxyl group.

[0012] The present invention (I) relates to a thermoplastic resin composition for a coolant transport line. The coolant transport line refers to a line for transporting a coolant in an air conditioning system or the like. The line can be a flexible hose or a rigid line that is not easily deformed. The thermoplastic resin composition according to the invention can be used, in particular, to manufacture a hose for transporting a coolant in the air conditioning system of a motor vehicle. The coolant transport line typically comprises an inner line, a reinforcing layer, and an outer line, and the thermoplastic resin composition according to the invention can be used, in particular, to manufacture the inner line of the coolant transport line.Examples of refrigerants used in an air conditioning system can include hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), hydrocarbons, carbon dioxide, and ammonia; examples of HFCs include R410A, R32, R404A, R407C, R507A, and R134a; examples of HFOs include R1234yf, R1234ze, R1233zd, R1123, R1224yd, and R1336mzz; and examples of hydrocarbons include methane, ethane, propane, propylene, butane, isobutane, hexafluoropropane, and pentane.

[0013] The thermoplastic resin composition according to the invention comprises a matrix and a domain dispersed in the matrix. In other words, the thermoplastic resin composition according to the invention has a so-called sea-island structure. The matrix corresponds to a sea, and the domain corresponds to an island. The ratio between the matrix and the domain is not limited as long as the effects according to the invention are exerted, and preferably the volume ratio of the matrix to the volume ratio of the domain in the thermoplastic resin composition is 25 to 50 vol% or 50 to 75 vol%, respectively. The volume ratio of the matrix in the thermoplastic resin composition is particularly preferably 25 to 40 vol%, and even more preferably 30 to 40 vol%. If the volume ratio of the matrix is ​​too low, a phase inversion between the matrix and the domain can occur, leading to a reversal of the sea-island structure.If the volume ratio of the matrix is ​​too high, the content of the thermoplastic resin that forms the matrix can increase, which can lead to an undesirable flexibility.

[0014] The matrix comprises a thermoplastic resin. The thermoplastic resin must have a melting point or glass transition temperature of at least 150°C and an oxygen permeability coefficient of at least 0.004 cm⁻¹. 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and at a relative humidity of 0% or comprises a thermoplastic resin with a melting point or glass transition point of not less than 150°C and with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and a relative humidity of 0%.

[0015] When the thermoplastic resin composition according to the invention is used for a line for transporting a coolant in the air conditioning system of a motor vehicle, such a coolant transport line, manufactured using the thermoplastic resin composition according to the invention, is located in an engine compartment of such a motor vehicle, and the engine compartment has a portion whose temperature reaches approximately 150°C. Therefore, the matrix preferably comprises a thermoplastic resin with a melting point or glass transition point of not less than 150°C. The thermoplastic resin preferably has a melting point or glass transition point of 150 to 300°C, and particularly preferably a melting point or glass transition point of 170 to 270°C. If the melting point or glass transition point of the thermoplastic resin is too high, the thermoplastic resin composition's moldability deteriorates.

[0016] Examples of thermoplastic resin with a melting point or glass transition point of not less than 150°C (hereinafter also referred to as "high melting point resin") may include, but are not limited to, a polyamide, a polyester, an ethylene-vinyl alcohol copolymer, a polycarbonate, a polyketone, a polyvinyl alcohol, a polyvinyl chloride, a polyvinylidene chloride, a polyphenylene sulfide, a polysulfone, a polyacetal, a polyphenylene ether, a polyetheretherketone, a polyimide and a polymethylpentene.

[0017] Examples of thermoplastic resin with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2·day·mmHg) at a temperature of 21°C and at a relative humidity of 0% (hereinafter also referred to as "low oxygen permeability resin") may include a polyamide, a polyester, an ethylene vinyl alcohol copolymer, a polycarbonate, a polyketone, a polyvinyl alcohol, a polyvinyl chloride, a polyvinylidene chloride and a polyimide.

[0018] The “oxygen permeability coefficient at a temperature of 21°C and at a relative humidity of 0%” is hereinafter simply referred to as the “oxygen permeability coefficient”.

[0019] The incorporation of the resin with low oxygen permeability into the matrix can result in the thermoplastic resin composition according to the invention having a desired oxygen permeability coefficient.

[0020] Examples of thermoplastic resin with a melting point or glass transition point of not less than 150°C and with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and at a relative humidity of 0% (hereinafter also referred to as "high melting point / low oxygen permeability resin") can include a polyamide, a polyester, an ethylene vinyl alcohol copolymer, a polycarbonate and a polyketone.

[0021] The incorporation of the resin with a high melting point / low oxygen permeability into the matrix can result in the thermoplastic resin composition according to the invention having the desired heat resistance and oxygen permeability coefficients.

[0022] Examples of polyamide include Nylon 6 with a melting point of 225°C and an oxygen permeability coefficient of 0.001 cm 3 mm / (m 2 ·day·mmHg), a nylon 6 / 66 copolymer with a melting point of 195°C and an oxygen permeability coefficient of 0.003 cm 3 mm / (m 2 ·day·mmHg), a nylon 6 / 12 copolymer with a melting point of 201°C and an oxygen permeability coefficient of 0.003 cm 3 mm / (m 2 ·day·mmHg), Nylon 66 with a melting point of 265°C, Nylon 11 with a melting point of 187°C, Nylon 12 with a melting point of 176°C, Nylon 610 with a melting point of 225°C, Nylon 46 with a melting point of 295°C, Nylon 6T with a melting point of 320°C, Nylon 9T with a melting point of 300°C and Nylon MXD6 with a melting point of 243°C. Nylon 6, a Nylon 6 / 12 copolymer and a Nylon 6 / 66 copolymer are preferred.

[0023] Examples of polyester include polyethylene terephthalate with a melting point of 256°C, polybutylene terephthalate with a melting point of 225°C and an oxygen permeability coefficient of 0.003 cm 3 mm / (m 2 ·day·mmHg) , polyethylene naphthalate with a melting point of 265°C and polybutylene naphthalate with a melting point of 243°C. Polybutylene terephthalate is preferred.

[0024] The ethylene-vinyl alcohol copolymer varies in melting point and oxygen permeability coefficient depending on the copolymerization fractions of ethylene and vinyl alcohol. A preferred copolymerization fraction of ethylene is 25 to 48 mol%. In particular, an ethylene-vinyl alcohol copolymer in which the copolymerization fraction of ethylene is 48 mol% has a melting point of 158°C and an oxygen permeability coefficient of 0.00003 cm⁻¹. 3 mm / (m 2preferably has a mean daily blood pressure (mmHg).

[0025] Examples of polycarbonate include bisphenol A-type polycarbonate with a glass transition point of 150°C.

[0026] Examples of the polyketone include a ketone-ethylene copolymer with a melting point of 255°C and a ketone-ethylene-propylene terpolymer with a melting point of 220°C.

[0027] The matrix may comprise any resin other than the high melting point resin, the low oxygen permeability resin and the high melting point / low oxygen permeability resin, as well as various additives, as long as the effects according to the invention are not impaired.

[0028] The proportion of the total amount of the high-melting-point resin, the low-oxygen-permeability resin, and the high-melting-point / low-oxygen-permeability resin in the matrix is ​​preferably not less than 50 wt.%, particularly preferably not less than 60 wt.%, and even more preferably not less than 70 wt.%. If the proportion in the matrix lies within this numerical range, the thermoplastic resin composition according to the invention can exhibit the desired heat resistance and the desired oxygen permeability coefficient.

[0029] The domain comprises rubber. The rubber comprises an isobutylene-based block copolymer comprising a polyisobutylene block and a polystyrene block, and an olefin-based or styrene-based polymer with at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, an acid anhydride group, and a carboxyl group.

[0030] Examples of the isobutylene-based block copolymer comprising a polyisobutylene block and a polystyrene block (hereinafter also referred to simply as "isobutylene-based block copolymer") include a styrene-isobutylene diblock copolymer, a styrene-isobutylene-styrene triblock copolymer, and a modified product thereof. A styrene-isobutylene diblock copolymer and a styrene-isobutylene-styrene triblock copolymer are preferred.

[0031] The incorporation of an isobutylene-based block copolymer into the rubber can result in the thermoplastic resin composition according to the invention having a desired oxygen permeability coefficient.

[0032] Examples of the olefin-based or styrene-based polymer with at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, an acid anhydride group and a carboxyl group (hereinafter also referred to as "olefin-based or styrene-based polymer with a specified functional group") include an α-olefin-based thermoplastic elastomer, a styrene-ethylene-butylene-styrene block copolymer, a styrene-ethylene-propylene-styrene block copolymer, an acid anhydride-modified ethylene-ethyl acrylate copolymer, a styrene-butadiene-styrene block copolymer and a styrene-isoprene-styrene block copolymer, each having an epoxy group, an amino group, a hydroxyl group, an acid anhydride group or a carboxyl group.At least one selected from the group consisting of an acid anhydride-modified α-olefin-based thermoplastic elastomer, an acid anhydride-modified styrene-ethylene-butylene-styrene block copolymer, an acid anhydride-modified styrene-ethylene-propylene-styrene block copolymer and an acid anhydride-modified ethylene-ethyl acrylate copolymer is preferred.

[0033] If the rubber comprises the olefin-based or styrene-based polymer with a specified functional group, it serves as a compatibilizing agent between the isobutylene-based block copolymer and the matrix resin, which contributes to the stabilization of the sea-island structure.

[0034] The proportion of the isobutylene-based block copolymer in the domain is preferably 50 to 95 wt.%, particularly preferably 60 to 95 wt.%, and even more preferably 70 to 95 wt.%. If the proportion of the isobutylene-based block copolymer is too low, the barrier properties of the thermoplastic resin composition may deteriorate. If the proportion of the isobutylene-based block copolymer is too high, the island-sea structure of the thermoplastic resin composition may break down, leading to deterioration of the barrier properties and processability.

[0035] The proportion of the olefin-based or styrene-based polymer with a specified functional group in the domain is preferably 5 to 50 wt.%, particularly preferably 5 to 40 wt.%, and even more preferably 5 to 30 wt.%. If the proportion of the olefin-based or styrene-based polymer with a specified functional group is too low, the island-sea structure of the thermoplastic resin composition may break down, leading to a deterioration in barrier properties and processability. If the proportion of the olefin-based or styrene-based polymer with a specified functional group is too high, the barrier properties of the thermoplastic resin composition may deteriorate.

[0036] The domain may comprise a rubber other than the isobutylene-based block copolymer and the olefin-based or styrene-based polymer with a specified functional group, as well as various additives, as long as the effects according to the invention are not impaired.

[0037] The thermoplastic resin composition preferably comprises at least one selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester, and a fatty acid amide. The inclusion of at least one selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester, and a fatty acid amide can further improve the thermoplastic resin composition with regard to its extrusion processability.

[0038] Examples of fatty acids include stearic acid, palmitic acid, and oleic acid. Stearic acid is preferred.

[0039] Examples of the fatty acid metal salt include calcium stearate, magnesium stearate, zinc stearate, and barium stearate. Calcium stearate is particularly preferred.

[0040] Examples of fatty acid esters include fatty acid esters obtained by esterification reactions of a higher fatty acid, obtained by hydrolysis of coconut oil, castor oil, palm oil, beef tallow, or the like, with a low alcohol, a higher alcohol, or a polyhydric alcohol.

[0041] Examples of fatty acid amides include stearylamide, palmitylamide, and oleylamide.

[0042] The content of at least one compound selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester, and a fatty acid amide is preferably 0.5 to 5 parts by weight, particularly preferably 1 to 4 parts by weight, and even more preferably 1 to 3 parts by weight, based on 100 parts by weight of the rubber in the thermoplastic resin composition. If the content is too high, the barrier properties of the thermoplastic resin composition may deteriorate.

[0043] At least one, selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester and a fatty acid amide, may be present either in the matrix or the domain, or may be present in both the matrix and the domain.

[0044] The thermoplastic resin composition preferably comprises a divalent metal oxide. The inclusion of a divalent metal oxide can further improve the extrusion processability of the thermoplastic resin composition.

[0045] Examples of the divalent metal oxide include zinc oxide, magnesium oxide, copper oxide, calcium oxide, and iron oxide. Zinc oxide or magnesium oxide is preferred, and zinc oxide is particularly preferred.

[0046] The content of the divalent metal oxide is preferably 0.5 to 10 parts by weight, particularly preferably 1 to 10 parts by weight, and even more preferably 3 to 8 parts by weight, based on 100 parts by weight of the rubber in the thermoplastic resin composition. If the content is too high, the fatigue resistance of the thermoplastic resin composition may deteriorate.

[0047] The divalent metal oxide can be present in either the matrix or the domain, or it can be present in both the matrix and the domain.

[0048] The thermoplastic resin composition preferably comprises a trihydric alcohol with a triazine ring. The inclusion of the trihydric alcohol with a triazine ring can improve the fatigue resistance of the thermoplastic resin composition.

[0049] The trihydric alcohol with a triazine ring is preferably tris(2-hydroxyethyl)isocyanurate, but is not limited to this.

[0050] The content of the trihydric alcohol with a triazine ring is preferably 0.1 to 8 parts by weight, particularly preferably 0.5 to 6 parts by weight, and even more preferably 1 to 5 parts by weight, based on 100 parts by weight of the rubber in the thermoplastic resin composition. If the content of the trihydric alcohol with a triazine ring is too high, the thermoplastic resin composition may be impaired with regard to extrusion processability.

[0051] The trivalent alcohol with a triazine ring can be present in either the matrix or the domain, or in both the matrix and the domain.

[0052] The thermoplastic resin forming the matrix preferably has a melt viscosity of no more than 300 Pa·s at a temperature of 250°C and a shear rate of 243.2 s⁻¹. -1(hereinafter also referred to simply as "melt viscosity"), preferably 50 to 300 Pa·s, particularly preferably 50 to 150 Pa·s. If the melt viscosity of the thermoplastic resin forming the matrix is ​​too high, phase inversion between the matrix and the domain can easily occur, making it impossible to increase the volume fraction of rubber in the domain. If the melt viscosity of the thermoplastic resin forming the matrix is ​​too low, rubber particles in the domain can hardly be finely dispersed, leading to a deterioration in fatigue resistance.

[0053] The melt viscosity of the thermoplastic resin that forms the matrix can be adjusted by the molecular weight of the thermoplastic resin.

[0054] The melt viscosity of the thermoplastic resin that forms the matrix can be measured with a capillary rheometer.

[0055] In the event that a large number of such thermoplastic resins forming the matrix are present, the melt viscosity measured in relation to a sample obtained by mixing such thermoplastic resins at a compounding ratio is defined as the melt viscosity of such thermoplastic resins forming the matrix.

[0056] The thermoplastic resin composition preferably has an oxygen permeability coefficient of not greater than 0.02 cm. 3 mm / (m 2 ·day·mmHg), especially preferred 0.015 cm 3 mm / (m 2 ·day·mmHg) or less, preferably not larger than 0.01 cm 3 mm / (m 2·day·mmHg), at a temperature of 21°C and a relative humidity of 0%. If the oxygen permeability coefficient of the thermoplastic resin composition lies within this numerical range, the thermoplastic resin composition also has improved barrier properties against a coolant and can therefore be suitable for use as a thermoplastic resin composition for a coolant transport line.

[0057] The oxygen permeability coefficient of the thermoplastic resin composition can be adjusted by the respective types and proportions of the thermoplastic resin forming the matrix and the rubber forming the domain.

[0058] The thermoplastic resin composition preferably has a 10% modulus of not greater than 10 MPa, particularly preferably not greater than 8 MPa, and even more preferably not greater than 6 MPa, at a temperature of 25°C and a relative humidity of 50% in a tensile test according to JIS K7161. If the 10% modulus of the thermoplastic resin composition is within this numerical range, the thermoplastic resin composition exhibits excellent flexibility and can therefore be suitablely used as a thermoplastic resin composition for a coolant transport line.

[0059] The 10% modulus of the thermoplastic resin composition can be adjusted by the respective types and proportions of the thermoplastic resin forming the matrix and the rubber forming the domain.

[0060] The thermoplastic resin composition, although not particularly restricted with regard to its manufacturing process, can be produced by kneading the thermoplastic resin and the rubber and, as required, at least one selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester and a fatty acid amide, the divalent metal oxide, the trivalent alcohol with a triazine ring and (one) further additive(s) by means of a twin-screw kneading extruder or the like.

[0061] The invention (II) provides a coolant transport line comprising a layer of the thermoplastic resin composition of the present invention (I) as an inner layer.

[0062] The coolant transport line according to the invention is preferably used in a hose for transporting a coolant in an air conditioning system, particularly preferably in a hose for transporting a coolant in an air conditioning system of a motor vehicle.

[0063] The coolant transport line preferably comprises an inner line, a reinforcing layer, and an outer line. At least one layer of the inner line in the coolant transport line according to the invention comprises the thermoplastic resin composition.

[0064] Although not particularly restricted in its manufacturing process, the coolant transport line can be produced as follows. The line can be manufactured by first extruding an inner tube, then braiding a fiber, which serves as a reinforcing layer, onto the tube, and finally covering the fiber with an outer tube by extrusion. EXAMPLES(1) Starting materials

[0065] The starting materials used in the following examples and comparison examples are as follows.

[0066] Nylon-1: Nylon 6, “UBE NYLON ® “1011FB, manufactured by UBE INDUSTRIES, LTD., and with a melting point of 225°C, an oxygen permeability coefficient of 0.001 cm 3 mm / (m 2 ·day·mmHg) and a melt viscosity of 90 Pa·s

[0067] Nylon-2: Nylon 6 / 12, “UBE NYLON ®“7024B, manufactured by UBE INDUSTRIES, LTD., and with a melting point of 201°C, an oxygen permeability coefficient of 0.003 cm 3 mm / (m 2 ·day·mmHg) and a melt viscosity of 270 Pa·s

[0068] Nylon-3: Nylon 6 / 66, “NOVAMID ® “2010R, manufactured by DSM, and with a melting point of 200°C, an oxygen permeability coefficient of 0.003 cm 3 mm / (m 2 ·day·mmHg) and a melt viscosity of 107 Pa·s

[0069] Nylon-4: Nylon 6, “UBE NYLON ® “1022B, manufactured by UBE INDUSTRIES, LTD., and with a melting point of 225°C, an oxygen permeability coefficient of 0.001 cm 3 mm / (m 2 ·day·mmHg) and a melt viscosity of 600 Pa·s

[0070] EVOH: Ethylene-vinyl alcohol copolymer with an ethylene content of 48 mol-%, “SoarnoL ®“H4815B, manufactured by NIHON GOSEI KAKO Co., Ltd., and a melting point of 158°C, an oxygen permeability coefficient of 0.00003 cm 3 mm / (m 2 ·day·mmHg) and a melt viscosity of 259 Pa·s

[0071] Polyester: Polybutylene terephthalate, “NOVADURAN ® “5010R5, manufactured by Mitsubishi Engineering-Plastics Corporation, and with a melting point of 224°C, an oxygen permeability coefficient of 0.003 cm 3 mm / (m 2 ·day·mmHg) and a melt viscosity of 300 Pa·s

[0072] SIBS: Styrene-isobutylene-styrene block copolymer, “SIBSTAR ® “102T, manufactured by KANEKA CORPORATION, which is non-crystalline and has an oxygen permeability coefficient of 0.076 cm 3 mm / (m 2 ·day·mmHg) has

[0073] Acid-modified styrene-based elastomer-1: maleic anhydride-modified styrene-ethylene-butylene-styrene block copolymer, “TUFTEC ® “M1913, manufactured by Asahi Kasei Corporation, is non-crystalline and has an oxygen permeability coefficient of 1,113 cm 3 mm / (m 2 ·day·mmHg) has

[0074] Acid-modified styrene-based elastomer-2: maleic anhydride-modified styrene-ethylene-butylene-styrene block copolymer “TUFTEC” ® “M1943, manufactured by KANEKA CORPORATION, which is non-crystalline and has an oxygen permeability coefficient of 1,355 cm 3 mm / (m 2 ·day·mmHg) has

[0075] Acid-modified polyolefin-1: maleic anhydride-modified α-olefin copolymer, "TAFMER ® “MH7020, manufactured by Mitsui Chemicals, Inc., which is non-crystalline and has a Oxygen permeability coefficients of 1,554 cm 3 mm / (m 2 ·day·mmHg) has

[0076] Acid-modified polyolefin-2: maleic anhydride-modified α-olefin copolymer, "TAFMER ® “MP0620, manufactured by Mitsui Chemicals, Inc., which is non-crystalline and has a Oxygen permeability coefficients of 1,436 cm 3 mm / (m 2 ·day·mmHg) has

[0077] Zinc oxide: Zinc oxide III, manufactured by SEIDO CHEMICAL INDUSTRY CO., LTD.

[0078] Stearic acid: technical-grade stearic acid, manufactured by Chiba Fatty Acid Co., Ltd.

[0079] Calcium stearate: Calcium stearate SC-PG, manufactured by SAKAI CHEMICAL INDUSTRY CO., LTD.

[0080] Trihydric alcohol with a triazine ring: Tris(2-hydroxyethyl)isocyanurate, “THEIC”, manufactured by SHIKOKU CHEMICALS CORPORATION (2) Production of the thermoplastic resin composition

[0081] Each thermoplastic resin composition shown in Tables 1 to 3 was prepared by the following procedure. First, a thermoplastic resin and zinc oxide were mixed to a zinc oxide content of 50 wt%, thus creating a zinc oxide masterbatch. If several thermoplastic resins were used and compounded, a masterbatch was prepared using the thermoplastic resin with the higher compounding ratio. Next, each starting material was fed into a twin-screw kneading extruder (manufactured by THE JAPAN STEEL WORKS, LTD.) at a compounding ratio shown in Tables 1 to 3 and kneaded at 235°C for 3 minutes. The kneaded product was continuously extruded from the extruder in the form of a strand, cooled with water, and then cut by a cutting device to obtain a pellet-shaped thermoplastic resin composition.The zinc oxide was added in such a way that it was compounded in the masterbatch in a desired quantity. (3) Evaluation of the thermoplastic resin composition

[0082] The melt viscosity of the thermoplastic resin forming the matrix, the oxygen permeability coefficient, the 10% modulus, the extrusion processability, and the dynamic fatigue resistance of the produced thermoplastic resin composition were evaluated. The evaluation results are presented in Tables 1 to 3.

[0083] The respective methods for measuring melt viscosity, oxygen permeability coefficient, 10% modulus, extrusion processability and dynamic fatigue resistance are described below. [Measurement of the melt viscosity of the thermoplastic resin that forms the matrix]

[0084] The melt viscosity (in Pa·s) of the thermoplastic resin forming the matrix was determined using a capillary rheometer “CAPILOGRAPH 1C”, manufactured by Toyo Seiki Seisaku-sho, ltd., with an opening of 1 mm in diameter and 10 mm in length, at a shear rate of 243 s⁻¹. -1 and measured at a temperature of 250°C for a retention time of 5 minutes. [Measurement of the oxygen permeability coefficient]

[0085] The oxygen permeability coefficient was measured at a temperature of 21°C and a relative humidity of 0% using OX-TRAN 1 / 50, manufactured by MOCON, Inc., with respect to a film obtained by extruding a sample in the form of a film with a thickness of 0.2 mm at 235°C using a T-nozzle extrusion device having a nozzle width of 550 mm and a φ40 mm single-screw extruder manufactured by Pla Giken Co., Ltd. [Measurement of the 10% module]

[0086] The 10% modulus was determined by extruding a sample in the form of a 1 mm thick film at 235°C using a T-nozzle extrusion device with a 200 mm nozzle width and a φ40 mm single-screw extruder manufactured by Pla Giken Co., Ltd., punching out a JIS 3 barbell so that the film extrusion direction in the resulting film was longitudinal, and performing a tensile test at a temperature of 25°C and a relative humidity of 50% according to JIS K7161 using an AUTOGRAPH tensile tester. ® , manufactured by Shimadzu Corporation, intended. [Assessment of extrusion processability]

[0087] A film with a thickness of 1 mm was obtained by extruding a sample at 235°C using a T-nozzle extrusion device having a nozzle width of 200 mm and a φ40 mm single-screw extruder manufactured by Pla Giken Co., Ltd., and was classified as "good" if it could be formed without problems, as "acceptable" if minor graining, hole formation, film end breakage or the like occurred, and as "unacceptable" if significant graining, hole formation, film end breakage or the like occurred. [Measurement of dynamic fatigue resistance]

[0088] Six JIS 3 dumbbells were die-cut from the film obtained under "Extrusion Processability Assessment", so that the film extrusion direction was a longitudinal direction, and each was repeatedly subjected to a 40% elongation (fatigue test at constant elongation). The barbells were subjected to a constant strain testing machine manufactured by UESHIMA SEISAKUSHO CO., LTD. at -35°C. The test was conducted until all barbells broke, and the endurance rating at a failure rate of 63.2%, as determined by a Weibull diagram, was defined as the dynamic fatigue strength. The value in Example 1 was assumed to be 100, and the endurance ratings in the other examples and comparison examples were each compared relative to this. Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Nylon-1 Weight part(s) 62,2 38,8 63,0 53,3 43,4 Nylon-2 Weight part(s) 8,7 17,3 Nylon-3 Weight part(s) 49,1 Nylon-4 Weight part(s) EVOH Weight part(s) polyester Weight part(s) SIBS Weight part(s) 80,0 80,0 30,0 50,0 95,0 80,0 Acid-modified styrene-based elastomer-1 Weight part(s) 20,0 20,0 70,0 50,0 5,0 Acid-modified styrene-based elastomer-2 Weight part(s) 20,0 Acid-modified polyolefin-1 Weight part(s) Acid-modified polyolefin-2 Weight part(s) zinc oxide Weight part (e) 5,0 3,0 5,0 5,0 5,0 5,0 Stearic acid Weight part(s) 1,0 0,5 1,0 1,0 1,0 1,0 Calcium stearate Weight part(s) 1,0 0,5 1,0 1,0 1,0 1,0 Trihydric alcohol with a triazine structure Weight part(s) In total Weight part(s) 169,2 142,8 170,0 169,0 167,7 156,1 Melt viscosity of the thermoplastic resin that forms the matrix Pa·s 90 90 90 93 96 107 Domain volume ratio Vol. 65 75 65 65 65 70 SIBS share in domain % by weight 80 80 30 50 95 80 Oxygen permeability coefficient of the thermoplastic resin composition cm 3 ·mm / (m 2 ·Tag.mmHg) 0,0081 0,0108 0,0200 0,0117 0,0093 0,0090 10% modulus of the thermoplastic resin composition MPa 5, 0 3,9 5,4 5,3 4,8 4,3 Extrusion processability of the thermoplastic resin composition good acceptable good good good good Dynamic fatigue resistance of the thermoplastic resin composition 100 140 90 100 110 150 Table 2 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Nylon-1 Weight part(s) 81,7 77,2 78,3 79,7 Nylon-2 Weight part(s) Nylon-3 Weight part(s) Nylon-4 Weight part(s) EVOH Weight part(s) 75,7 polyester Weight part(s) 136,3 SIBS Weight part(s) 65,0 70,0 60,0 60,0 60,0 60,0 Acid-modified styrene-based elastomer-1 Weight part(s) 35,0 30,0 Acid-modified styrene-based elastomer-2 Weight part(s) Acid-modified polyolefin-1 Weight part(s) 40,0 40,0 Acid-modified polyolefin-2 Weight part(s) 40,0 40,0 zinc oxide Weight part(s) 5, 0 5,0 5, 0 3, 0 0,5 10,0 Stearic acid Weight part(s) 1,0 1,0 0,2 1,0 1,5 0,5 Calcium stearate Weight part(s) 2, 0 1,0 0,3 4,0 3, 0 1,0 Trihydric alcohol with a triazine structure Weight part(s) In total Weight part (e) 183,7 243,3 187,2 185,2 183,3 191,2 Melt viscosity of the thermoplastic resin that forms the matrix Pa·s 259 300 90 90 90 90 Domain volume ratio Vol. 60 50 60 60 60 60 SIBS share in domain % by weight 65 70 60 60 60 60 Oxygen permeability coefficient of the thermoplastic resin composition cm 3 ·mm / (m 2 ·Tag·mmHg) 0,0004 0,0086 0,0113 0,0150 0,0134 0,0095 10% modulus of the thermoplastic resin composition MPa 10, 0 9,9 5,4 5,3 5,4 6,1 Extrusion processability of the thermoplastic resin composition good good good good good good Dynamic fatigue resistance of the thermoplastic resin composition 80 80 90 90 90 80 Table 3 Example 13 Example 14 Comparison example 1 Comparison example 2 cf. example 3 Nylon-1 Weight part(s) 62,1 52,6 77,4 79,3 Nylon-2 Weight part(s) Nylon-3 Weight part(s) Nylon-4 Weight part(s) 62,2 EVOH Weight part(s) polyester Weight part(s) SIBS Weight part(s) 80,0 80,0 100,0 80,0 Acid-modified styrene-based elastomer-1 Weight part(s) 20,0 20,0 100,0 20,0 Acid-modified styrene-based elastomer-2 Weight part(s) Acid-modified polyolefin-1 Weight part(s) Acid-modified polyolefin-2 Weight part(s) zinc oxide Weight part (e) 5,0 5,0 5,0 5,0 5,0 Stearic acid Weight part(s) 1,0 1,0 1,0 1,0 1,0 Calcium stearate Weight part(s) 1,0 1,0 1,0 1,0 1,0 Trihydric alcohol with a triazine structure Weight part(s) 0,1 8, 0 In total Weight part(s) 169,2 167,6 184,4 186,3 169,2 Melt viscosity of the thermoplastic resin that forms the matrix Pa·s 90 90 90 90 600 Domain volume ratio Vol. 65 65 60 60 65 SIBS share in domain % by weight 80 80 100 0 80 Oxygen permeability coefficient of the thermoplastic resin composition cm 3 ·mm / (m 2 ·Tag·mmHg) 0,0078 0,0075 - 0,0342 - 10% modulus of the thermoplastic resin composition MPa 5,1 5,7 - 5,5 - Extrusion processability of the thermoplastic resin composition good acceptable unacceptable good unacceptable Dynamic fatigue resistance of the thermoplastic resin composition 110 200 - 90 - COMMERCIAL APPLICABILITY

[0089] The thermoplastic resin composition according to the invention can be used in a suitable manner for the production of a coolant transport line.

Claims

[1] Thermoplastic resin composition for a coolant transport line, comprising a matrix comprising a thermoplastic resin and a rubber domain dispersed in the matrix, wherein the thermoplastic resin composition has an oxygen permeability coefficient of not greater than 0.02 cm 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and at a relative humidity of 0%, wherein the thermoplastic resin forming the matrix has a melt viscosity of not greater than 300 Pa·s at a temperature of 250°C and a shear rate of 243.2 s -1 exhibits that the thermoplastic resin is a thermoplastic resin with a melting point or a glass transition point of not less than 150°C and a thermoplastic resin with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2·day·mmHg) at a temperature of 21°C and at a relative humidity of 0% or a thermoplastic resin with a melting point or glass transition point of not less than 150°C and with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and at a relative humidity of 0%, and the rubber comprises an isobutylene-based block copolymer comprising a polyisobutylene block and a polystyrene block, and an olefin-based or styrene-based polymer with at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, an acid anhydride group and a carboxyl group. [2] Thermoplastic resin composition for a coolant transport line according to claim 1, wherein the thermoplastic resin composition has a 10% modulus of not greater than 10 MPa at a temperature of 25°C and at a relative humidity of 50% in a tensile test according to JIS K7161. [3] Thermoplastic resin composition for a coolant transport line according to claim 1 or 2, wherein the thermoplastic resin is at least one selected from the group consisting of a polyamide, a polyester, an ethylene vinyl alcohol copolymer, a polycarbonate and a polyketone. [4] Thermoplastic resin composition for a coolant transport line according to any one of claims 1 to 3, wherein the isobutylene-based block copolymer comprises a styrene-isobutylene diblock copolymer and / or a styrene-isobutylene-styrene triblock copolymer. [5] Thermoplastic resin composition for a coolant transport line according to any one of claims 1 to 4, wherein the olefin-based or styrene-based polymer is at least one functional group selected from the group consisting of an epoxy group, an amino group, a hydroxyl group, an acid anhydride group and a carboxyl group, and at least one functional group selected from the group consisting of an acid anhydride-modified α-olefin-based thermoplastic elastomer, an acid anhydride-modified styrene-ethylene-butylene-styrene block copolymer, an acid anhydride-modified styrene-ethylene-propylene-styrene block copolymer and an acid anhydride-modified ethylene-ethyl acrylate copolymer. [6] Thermoplastic resin composition for a coolant transport line according to any one of claims 1 to 5, wherein the thermoplastic resin composition comprises the matrix in a volume ratio of 25 to 50 vol% and the domain in a volume ratio of 50 to 75 vol%. [7] Thermoplastic resin composition for a coolant transport line according to any one of claims 1 to 6, wherein the proportion of the total amount of thermoplastic resin has a melting point or glass transition point of not less than 150°C, and the proportion of thermoplastic resin has an oxygen permeability coefficient of not greater than 0.04 cm 3 mm / (m 2 ·day·mmHg) at a temperature of 21°C and at a relative humidity of 0% and of the thermoplastic resin with a melting point or a glass transition point of 150°C or more and with an oxygen permeability coefficient of not greater than 0.004 cm 3 mm / (m 2·day·mmHg) at a temperature of 21°C and at a relative humidity of 0% in the matrix is ​​not less than 50 wt%. [8] Thermoplastic resin composition for a coolant transport line according to any one of claims 1 to 7, wherein the proportion of the isobutylene-based block copolymer in the domain is 50 to 95 wt.%. [9] Thermoplastic resin composition for a coolant transport line according to any one of claims 1 to 8, wherein the thermoplastic resin composition comprises 0.5 to 5 parts by weight of at least one selected from the group consisting of a fatty acid, a fatty acid metal salt, a fatty acid ester and a fatty acid amide, based on 100 parts by weight of the rubber in the thermoplastic resin composition. [10] Thermoplastic resin composition for a coolant transport line according to any one of claims 1 to 9, wherein the thermoplastic resin composition comprises 0.5 to 10 parts by weight of a divalent metal oxide, based on 100 parts by weight of the rubber in the thermoplastic resin composition. [11] Thermoplastic resin composition for a coolant transport line according to any one of claims 1 to 10, wherein the thermoplastic resin composition comprises 0.1 to 8 parts by weight of a trihydric alcohol with a triazine backbone, based on 100 parts by weight of the rubber in the thermoplastic resin composition. [12] Coolant transport line comprising a layer of the thermoplastic resin composition according to any one of claims 1 to 11 as an inner layer.