Insulation coating

Abstract

The present invention relates to a novel use of a polyamide-based composition in the preparation of insulating coatings, which exhibit excellent dielectric strength, high volume resistivity, and outstanding flame retardancy. The insulating coatings can be used in various technical fields, particularly in electrical and electronic systems, new energy vehicles, electrical insulation materials for motors (motor coil bobbins are provided with insulating coatings), insulating jackets, and heat-resistant parts or components.

Description

[Technical Field]

[0001] The present invention relates to a polyamide-based composition having excellent dielectric strength, high volume resistivity, and outstanding flame retardant performance, which can be used in various technical fields, particularly in electrical and electronic systems, new energy vehicles, electrical insulating materials for motors (motor coil bobbins are provided with insulating coatings), insulating jackets, and heat-resistant parts or components, and to novel applications of insulating coatings prepared from the polyamide-based composition.

[0002] Background of the Invention Electric and hybrid vehicles require electric motors and motor-generators. Electric motor applications require insulating and heat-resistant properties for devices such as motor winding insulation, electrical coils, wires, and cables, as well as for capacitor media, which require film or paper-like products. The materials used to manufacture such devices must be robust enough to ensure safety regarding the insulation. Such films are generally made from synthetic resins.

[0003] Japanese Patent Application Laid-Open No. 11-341714 discloses a motor stator having a covering made of polyphenylene sulfide and glass fiber, but the thickness of such a covering cannot meet the thickness requirements of the insulating sheet.

[0004] Japanese Patent Application Laid-Open No. 2008-263704 discloses insulating paper provided with heat-resistant sheets made of aromatic polyamide fiber on both sides of the insulating paper, and an adhesive is used to connect the insulating paper to the resin molded body.

[0005] International Publication No. 2015 / 033696 discloses a motor bobbin in which an insulating sheet is impregnated with a resin molding without the use of adhesive. The surface of the insulating sheet is made of aramid paper made from aramid fiber and aramid short fiber. The aramid insulating paper is made from chopped or precipitated fibers using a wet papermaking process and formed using a hot press process, which provides a good solution for high melting temperatures, excellent heat resistance and insulation performance, inherent flame retardancy, and excellent chemical resistance.

[0006] However, aramid insulating paper is very expensive. Improvements have been developed to reduce costs and reduce the sacrifice of properties by using impregnation or lamination. One example is a composite of a polymer coating and polymer fiber, such as a polyester coating and polyester fiber, a polyester coating and polyaramid fiber, or a polyimide coating and polyaramid fiber. Composite materials combine the combined properties of the coating and fiber materials, significantly improving the tear resistance and impregnation of the insulating material, providing better performance than single materials and being easier to use. However, the cost of composite materials remains high.

[0007] Polyester coatings, such as polyethylene terephthalate coatings, are widely used in various industrial applications, but their heat resistance and dimensional stability cannot meet the requirements for practical industrial applications.

[0008] Japanese Patent Publication No. 2000-186141 discloses a semi-aromatic polyamide sheet. However, numerous fish eyes were observed during the manufacturing process. Japanese Patent Publication No. 2018-135414 also discloses a semi-aromatic polyamide sheet containing a black pigment for use in laser welding. However, this sheet cannot be used as an insulating coating.

[0009] These improvements still fall short of practical applications, and there is a need for insulating coatings that have low thickness, good flame retardancy, high dielectric strength, high volume resistivity, and low cost.

[0010] Summary of the Invention An object of the present invention is to provide a novel use of polyamide-based compositions in the preparation of insulating coatings.

[0011] Surprisingly, the present inventors have found that insulating coatings having a dielectric strength of at least 40 KV / mm at room temperature can be achieved by extruding a polyamide-based composition, followed by stretching, heat setting and cooling procedures. A) 69 to 89.9 wt% of polyamide; B) 10 to 25 wt. % of a flame retardant; C) 0.1 to 1.0 wt% of an acid scavenger; D) 0 to 5 wt. % of further additives; and the total weight percentage of components A) to D) is 100%.

[0012] Another object of the present invention is to provide an insulating coating that exhibits excellent dielectric strength, high volume resistivity, and excellent flame retardant performance.

[0013] The insulating coating of the present invention exhibits excellent flame retardancy approaching V-0 UL94 VTM for a 0.20 mm thick test piece and V-0 UL94 for a 0.8 mm thick test piece.

[0014] The insulating coating of the present invention is capable of passing the GWFI (Glow Wire Flammability Index) test according to DIN EN 60695-2-12 at 960°C on test specimens with thicknesses of 0.75 mm and 1.5 mm.

[0015] The insulating coating of the present invention has a dielectric strength of more than 40 KV / mm when measured in a conditioned state at room temperature in Midel 7131 ester solution according to IEC 60243-1.

[0016] The insulating coating of the present invention has a dielectric strength of more than 70 KV / mm when measured in a Midel 7131 ester solution in a dry state at room temperature in accordance with IEC 60243-1.

[0017] The insulating coating of the present invention has a dielectric strength of more than 40 KV / mm when measured in a dry state in Midel 7131 ester solution at 150°C in accordance with IEC 60243-1.

[0018] The insulating coating of the present invention has a dielectric strength loss of 40% or less, preferably 35%, at 120°C compared to the dielectric strength measured in a dry state at room temperature in Midel 7131 ester solution according to IEC 60243-1.

[0019] The insulating coating of the present invention has a dielectric strength loss of 45% or less, preferably 37%, at 150°C compared to the dielectric strength measured in a dry state at room temperature in Midel 7131 ester solution according to IEC 60243-1.

[0020] Yet another object of the present invention is to provide the use of said insulating coating for manufacturing components, in particular electrical insulating parts (such as coil bobbins) for electrical and electronic systems, new electric vehicles, and motors.

[0021] Detailed Description of the Invention Unless otherwise defined, all technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which the present invention belongs. The basic definitions or explanations set forth above in the general terms or preferred ranges apply to the final product, and correspondingly to the starting materials and intermediates. These basic definitions can be combined with each other as desired, i.e., include combinations between the general definitions and / or the respective preferred ranges and / or embodiments.

[0022] All embodiments and preferred embodiments disclosed herein can be combined as desired and are considered to be within the scope of the present invention.

[0023] The terms "a," "an," and "the" are used interchangeably with the term "at least one." The phrases "at least one of" and "comprises at least one of," following a list, refer to any one of the items in the list, and any combination of two or more items in the list. All numerical ranges include their endpoints and non-integer values ​​between the endpoints, unless otherwise stated.

[0024] The term "about" refers to a range of numbers that one of skill in the art would consider equivalent to the recited value, in the context of achieving the same function or result.

[0025] Unless otherwise specified, all percentages (%) are "percent by weight."

[0026] The term "unit" refers to the repeating units that make up a polyamide, unless otherwise specified.

[0027] As used herein, the term "PA" refers to polyamide. The term "PA* / PA**" refers to a copolymer of PA* and PA**.

[0028] A) 69 to 89.9 wt% of polyamide; B) 10 to 25 wt. % of a flame retardant; C) 0.1 to 1.0 wt% of an acid scavenger; D) 0 to 5 wt. % of further additives; and the total weight percent of components A) through D) is 100%.

[0029] In a preferred embodiment, the insulating coating is A) 72 to 78.7 wt.% polyamide; B) 19.85 to 23 wt. % of a flame retardant; C) 0.15 to 0.4 wt % of an acid scavenger; D) 1.3 to 4.6 wt. % of further additives; and the total weight percentage of components A) to D) is 100%.

[0030] Preferably, the polyamide is selected from at least one semi-crystalline, semi-aromatic polyamide having crystalline domains as evidenced by the presence of a melting peak having a melting enthalpy of at least 5 J / g, as measured by differential scanning calorimetry (DSC) according to ISO 11357 at a heating rate of 10 K / min.

[0031] The semi-crystalline, semi-aromatic polyamides of the present invention comprise dicarboxylic acid units, diamine units, and optionally units derived from other monomers such as amino acids and / or lactam units, where the dicarboxylic acid units or diamine units have aromatic groups. For example, the semi-aromatic polyamides comprise aromatic dicarboxylic acid units and aliphatic diamine units, or aliphatic and / or alicyclic dicarboxylic acid units and aromatic diamine units.

[0032] The aromatic dicarboxylic acid unit can typically be derived from an aromatic dicarboxylic acid. The aliphatic dicarboxylic acid unit can typically be derived from an aliphatic dicarboxylic acid and / or an aliphatic dicarboxylic acid chloride. The alicyclic dicarboxylic acid unit can typically be derived from an alicyclic dicarboxylic acid and / or an alicyclic dicarboxylic acid chloride.

[0033] The aliphatic or aromatic diamine units may typically be derived from an aliphatic or aromatic diamine, respectively.

[0034] The amount of the other monomer is preferably 0 to 20 mol %, more preferably 0 to 15 mol %, and even more preferably 0 to 10 mol %, based on all units constituting the semi-crystalline semi-aromatic polyamide.

[0035] The aromatic dicarboxylic acid in the present invention preferably contains 8 to 20 carbon atoms, more preferably 8 to 14 carbon atoms, and is, for example, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and / or diphenyldicarboxylic acid, more preferably terephthalic acid, naphthalenedicarboxylic acid, a mixture of terephthalic acid and isophthalic acid, or a mixture of terephthalic acid and naphthalenedicarboxylic acid.

[0036] The aliphatic dicarboxylic acid in the present invention preferably contains 4 to 36 carbon atoms, more preferably 5 to 36 carbon atoms, and most preferably 5 to 20 carbon atoms or 36 carbon atoms, for example, 5, 6, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, and / or 36 carbon atoms. Examples of aliphatic dicarboxylic acids include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanoic acid, hexadecanedioic acid, octadecanedioic acid, dimer acids having 36 carbon atoms, and mixtures thereof, with adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and mixtures thereof being more preferred.

[0037] The aliphatic dicarboxylic acid chloride in the present invention preferably contains 9 to 36 carbon atoms, more preferably 9 to 20 carbon atoms, and more preferably 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 carbon atoms. Examples of aliphatic dicarboxylic acid chlorides are azelayl chloride, sebacoyl chloride, undecandioyl dichloride, and mixtures thereof.

[0038] The alicyclic dicarboxylic acid in the present invention preferably contains 4 to 20 carbon atoms, more preferably 8 to 20 carbon atoms, and more preferably contains one carbon skeleton selected from the group consisting of cyclohexane, cyclopentane, cyclohexylmethane, dicyclohexylmethane, bis(methylcyclohexyl), and mixtures thereof, and most preferably is selected from the group consisting of cis- and trans-cyclopentane-1,3-dicarboxylic acid, cis- and trans-cyclopentane-1,4-dicarboxylic acid, cis- and trans-cyclohexane-1,2-dicarboxylic acid, cis- and trans-cyclohexane-1,3-dicarboxylic acid, cis- and trans-cyclohexane-1,4-dicarboxylic acid, and mixtures thereof.

[0039] The aliphatic diamine in the present invention may be a linear aliphatic diamine or a branched aliphatic diamine, preferably a linear aliphatic diamine. The aliphatic diamine preferably contains 4 to 36 carbon atoms, more preferably 4 to 22 or 36 carbon atoms, and most preferably 4 to 14 carbon atoms, for example, 4, 5, 6, 8, 9, 10, 11, 12, 13, or 14 carbon atoms. Examples of linear aliphatic diamines include 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,16-hexadecanediamine, 1,18-octadecanediamine, 1,20-eicosanediamine, 1,22-docosanediamine, and and mixtures thereof, preferably 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, and mixtures thereof, and more preferably 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, and mixtures thereof. Examples of branched aliphatic diamines are 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2-methyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine, 2,4,4-trimethylhexamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4-dimethyloctanediamine and mixtures thereof, preferably 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2-methyl-1,8-octanediamine, 2,4,4-trimethylhexamethylenediamine, 2,2,4-trimethylhexamethylenediamine and mixtures thereof.

[0040] The aromatic diamine in the present invention is preferably selected from the group consisting of m-xylylenediamine (MXD), p-xylylenediamine (PXD), bis(4-aminophenyl)methane, 3-methylbenzidine, 2,2-bis(4-aminophenyl)propane, 1,1-bis(4-aminophenyl)cyclohexane, 1,2-diaminobenzene, 1,3-diaminobenzene, 1,4-diaminobenzene, 1,2-diaminonaphthalene, 1,3-diaminonaphthalene, 1,4-diaminonaphthalene, 2,3-diaminotoluene, N,N'-dimethyl-4,4'-biphenyldiamine, bis(4-methylaminophenyl)methane, 2,2'-bis(4-methylaminophenyl)propane, and mixtures thereof, and more preferably MXD and / or PXD.

[0041] Suitable amino acids in the present invention preferably contain 4 to 20 carbon atoms, more preferably 4 to 14 carbon atoms, for example 9, 10, 11, 12 or 13. Examples of amino acids are 4-aminobutanoic acid, 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and mixtures thereof.

[0042] Suitable lactams according to the present invention preferably contain 4 to 12 carbon atoms, more preferably 5 to 12. Examples of lactams are 2-pyrrolidone (γ-butyrolactam), 2-piperidone (δ-valerolactam), ε-caprolactam, capryllactam, decanolactam, undecanolactam, enantholactam and / or lauryllactam, preferably ε-caprolactam and / or undecanolactam.

[0043] In a preferred embodiment of the present invention, the semi-crystalline semi-aromatic polyamide comprises dicarboxylic acid units and diamine units, and 0 to 20 mol % of units derived from an amino acid and / or a lactam, based on the total moles of units constituting the semi-crystalline semi-aromatic polyamide; i. The dicarboxylic acid units are derived from an aromatic dicarboxylic acid (a-1) or a combination of an aromatic dicarboxylic acid (a-1) and an aliphatic dicarboxylic acid (a-3) and / or an alicyclic dicarboxylic acid (a-2) or other dicarboxylic acids. The aromatic dicarboxylic acid (a-1) is preferably present in an amount of 60 to 100 mol %, and the other dicarboxylic acid (a-2) is preferably present in an amount of 0 to 40 mol %, based on the total moles of the dicarboxylic acid units constituting the semi-crystalline semi-aromatic polyamide. The diamine units are derived from an aliphatic diamine (b-1) or a combination of an aliphatic diamine (b-1) and an aromatic diamine (b-2). The aliphatic diamine (b-1) is preferably present in an amount of 80 to 100 mol % and the aromatic diamine (b-2) is preferably present in an amount of 0 to 20 mol % based on the total moles of the diamine units constituting the semi-crystalline, semi-aromatic polyamide. ii. The dicarboxylic acid units are derived from an aliphatic dicarboxylic acid (a-3) or a combination of an aliphatic dicarboxylic acid (a-3) and an alicyclic dicarboxylic acid. Based on the total moles of dicarboxylic acid units constituting the semi-crystalline semi-aromatic polyamide, the aliphatic dicarboxylic acid (a-3) is preferably present in an amount of 80 to 100 mol %, and the alicyclic dicarboxylic acid is preferably present in an amount of 0 to 20 mol %; The diamine units are derived from an aromatic diamine (b-2) or a combination of an aromatic diamine (b-2) and an aliphatic diamine (b-1). The aromatic diamine (b-2) is preferably present in an amount of 80 to 100 mol % and the aliphatic diamine (b-1) is preferably present in an amount of 0 to 20 mol % based on the total moles of the diamine units constituting the semi-crystalline, semi-aromatic polyamide.

[0044] In a preferred embodiment, the semi-crystalline, semi-aromatic polyamide comprises dicarboxylic acid units and diamine units, the dicarboxylic acid units being derived from aromatic dicarboxylic acids (a-1) or combinations of aromatic dicarboxylic acids (a-1) with other dicarboxylic acids (a-2), including aliphatic dicarboxylic acids (a-3) and / or alicyclic dicarboxylic acids. The aromatic dicarboxylic acid (a-1) is terephthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, a combination of terephthalic acid and isophthalic acid, or a combination of terephthalic acid and naphthalenedicarboxylic acid, and the aromatic dicarboxylic acid (a-1) is preferably present in an amount of 60 to 100 mol%, more preferably 80 to 100 mol%, even more preferably 90 to 100 mol%, and most preferably 95 to 100 mol%, based on the total moles of dicarboxylic acid units constituting the semicrystalline semi-aromatic polyamide. The other dicarboxylic acid (a-2) is preferably present in an amount of 0 to 40 mol%, more preferably 0 to 20 mol%, even more preferably 0 to 10 mol%, and most preferably 5 mol% or less, based on the total moles of dicarboxylic acid units constituting the semicrystalline semi-aromatic polyamide. The diamine units are derived from an aliphatic diamine (b-1) or a combination of an aliphatic diamine (b-1) and an aromatic diamine (b-2). The aliphatic diamine (b-1) is preferably present in an amount of 80 to 100 mol%, more preferably 90 to 100 mol%, and most preferably 95 to 100 mol%, based on the total moles of diamines constituting the semicrystalline, semiaromatic polyamide. The aromatic diamine (b-2) is preferably present in an amount of 0 to 20 mol%, more preferably 0 to 10 mol%, and most preferably 0 to 5 mol%, based on the total moles of diamine units constituting the semicrystalline, semiaromatic polyamide.

[0045] In a preferred embodiment, the semi-crystalline semi-aromatic polyamide comprises dicarboxylic acid units and diamine units, the dicarboxylic acid units being derived from an aromatic dicarboxylic acid (a-1) and 0 to 10 mol %, more preferably 0 to 5 mol %, of another dicarboxylic acid (a-2); the aromatic dicarboxylic acid (a-1) comprises 10 to 40 mol%, more preferably 15 to 30 mol%, and most preferably 20 to 30 mol% of isophthalic acid and 60 to 90 mol%, more preferably 70 to 85 mol%, and most preferably 70 to 80 mol% of at least one aromatic dicarboxylic acid selected from the group consisting of terephthalic acid, naphthalenedicarboxylic acid, and biphenyldicarboxylic acid, and is preferably terephthalic acid or a combination of terephthalic acid and naphthalenedicarboxylic acid; and the other dicarboxylic acid is (a-2) an aliphatic dicarboxylic acid and / or an alicyclic dicarboxylic acid, the mole percentages being based on the total moles of dicarboxylic acid units constituting the semicrystalline semi-aromatic polyamide; The diamine units are derived from an aliphatic diamine (b-1) or a combination of an aliphatic diamine (b-1) and an aromatic diamine (b-2). Based on the total moles of diamine units constituting the semi-crystalline, semi-aromatic polyamide, the aliphatic diamine (b-1) is preferably present in an amount of 90 to 100 mol%, more preferably 95 to 100 mol%, and the aromatic diamine (b-2) is preferably present in an amount of 0 to 10 mol%, more preferably 0 to 5 mol%.

[0046] In a more preferred embodiment, the aliphatic dicarboxylic acid (a-3) of the other dicarboxylic acid (a-2) is preferably glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanoic acid, hexadecanedioic acid, or octadecanedioic acid, more preferably glutaric acid, adipic acid, sebacic acid, and / or dodecanedioic acid.

[0047] In a more preferred embodiment, the aliphatic diamine (b-1) is a linear aliphatic diamine (b-1a) or a combination of a linear aliphatic diamine and a branched aliphatic diamine (b-1b). The linear aliphatic diamine (b-1a) is preferably selected from the group consisting of 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine. The branched aliphatic diamine (b-1b) is preferably selected from the group consisting of 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2-methyl-1,8-octanediamine, 2,4,4-trimethylhexamethylenediamine, and 2,2,4-trimethylhexamethylenediamine.

[0048] Examples of semi-crystalline semi-aromatic polyamides are polyamide MXD5, polyamide PXD5, polyamide MXD6, polyamide PXD6, polyamide MXD9, polyamide PXD9, polyamide MXD10 and / or polyamide PXD10.

[0049] The polyamides in the present invention may include polyamide copolymers or blends of two or more polyamides and their copolymers.

[0050] Semi-crystalline semi-aromatic polyamides are -R represents one or more of a linear aliphatic diamine and a branched aliphatic diamine; -T represents terephthalic acid; -I represents isophthalic acid, -A represents one or more aromatic diamines; -Y represents one or more aliphatic dicarboxylic acids; -V represents one or more of the lactams This is aptly represented by the annotation:

[0051] Suitable semi-crystalline semi-aromatic polyamides are Based on the total moles of -(T)+(I), 60 to 100 mol % of (T), 0 to 40 mol % of (I), preferably 60 to 85 mol % of (T), 15 to 40 mol % of (I), more preferably 65 to 80 mol % of (T), 20 to 35 mol % of (I), and 100 mol % of (R), where R is a linear or branched aliphatic polyamide preferably having 4 to 36 carbon atoms, more preferably 5 to 18 carbon atoms, and most preferably 6 to 12 carbon atoms. Examples of these polyamides include PA4T / 4I, PA4T / 6I, PA5T, PA5T / 5I, PA6T, PA6T / 6I, PA6T / 8T, PA6T / 10T, PA6T / 10I, PA9T, PA10T, PA12T, PA10T / 10I, PA6T / 9T, PA6T / 12T, PA4T / 6T / DT, PA4T / 10T / DT, PA4T / 4I / 6T / 6I / DT / DI, PA6T / 12T / 6I / 12I, PA6T / 10T / 6I, The compound includes PA4T / 6T / 4I / 6I, PA5T / 6T / 5I / 6I, PA5T / 4T / 5I / 4I, PA4T / 10T / 5I / 10I, PA4T / 6T / DT, PA4T / 10T / DT, or PA4T / 4I / 6T / 6I / DT / DI, preferably PA5T, PA6T, PA9T, PA10T, PA6T / 6I, PA6T / 10T, PA6T / 12T, PA6T / 10T / 6I, PA6T / DT, or PA6T / DT / 6I / DI, where D is 2-methylpenta-methylenediamine or 3-methyl-1,5-pentanediamine, or a mixture thereof, and D is in an amount of 0 to 20 mol %, preferably 0 to 10 mol %, of the total moles of (R).

[0052] In a preferred embodiment, the semi-crystalline semi-aromatic polyamide is PA6T / 6I containing 65 to 80 mol % of (T) and 20 to 35 mol % of (I).

[0053] In a preferred embodiment, the semi-crystalline, semi-aromatic polyamide is PA6T / 10T containing 10 to 60 mol% (6T) and 40 to 90 mol% (10T), preferably 10 to 40 mol% (6T) and 60 to 90 mol% (10T).

[0054] In one preferred embodiment, the semi-crystalline, semi-aromatic polyamide is PA6T / 10T / 6I, which contains 60-90 mol % of (6T), 5-40 mol % of (6I) and 5-45 mol % of (10T).

[0055] In one preferred embodiment, the semi-crystalline, semi-aromatic polyamide is PA6T / 10T / 6, which contains 60-85 mol % (6T), 15-40 mol % (10T), and 5-15 mol % caprolactam.

[0056] Suitable semi-crystalline semi-aromatic polyamides are Based on the total moles of (T)+(I)+(V)+(Y), 60 to 100 mol% of (T), 0 to 40 mol% of (I), 0 to 10 mol% of (V), preferably 0 to 5 mol% of (V), 0 to 80 mol% of (Y), preferably 0 to 60 mol% of (Y), more preferably 0 to 40 mol% of (Y). The polyamides can be represented by PART / RY, PART / V, PART / RI / RY, or PART / RI / V, including the following: wherein R is a linear aliphatic polyamide preferably having 4 to 36 carbon atoms, more preferably 5 to 18 carbon atoms, and most preferably 6 to 12 carbon atoms. Examples of these polyamides include PA5T, PA5T / 5I, PA5T / 6T / 5I / 6I, PA5T / 4T / 5I / 4I, PA4T / 10T / 5I / 10I, PA5T / 510, PA6T, PA6T / 6, PA6T / 12, PA6T / 6I / 6, PA6T / 66, PA4T / 410, PA6T / 610, PA6T / 612, PA6T / 1012, and PA9T. , PA9T / 612, PA9T / 1012, PA10T, PA10T / 106, PA10T / 612, PA10T / 1012, PA6T / 6I / 66, PA10T / 12, PA10T / 11, PA11T, PA12T, and PA6T / 6I / 12, preferably PA6T / 6, PA66 / 6T, PA6T / 610, or PA6T / 612.

[0057] In a preferred embodiment, PART / RY contains 60 to 100 mol % of (T) and 0 to 40 mol % of (Y), where R is 1,6-hexanediamine, 1,9-nonanediamine, or 1,10-decanediamine, and Y is dodecanedioic acid.

[0058] The semi-crystalline, semi-aromatic polyamide of the present invention has a melting temperature (Tm) of 250° C. to 350° C., preferably 280° C. to 320° C., and most preferably 305° C. to 315° C. The melting temperature is defined as the temperature corresponding to the endothermic peak in a differential scanning calorimetry (DSC) curve, which is obtained by DSC measurement at a heating rate of 10 K / min in accordance with ISO 11357.

[0059] The semi-crystalline, semi-aromatic polyamide of the present invention preferably has a viscosity number of 60 to 150 ml / g, more preferably 110 to 130 ml / g, measured in a 0.5 wt. % solution in 96 wt. % sulfuric acid according to the ISO 307-2007 method.

[0060] In a preferred embodiment, the semi-crystalline, semi-aromatic polyamide is selected from polyamide MXD6, polyamide 12T, polyamide 11T, polyamide 10T, polyamide 9T, polyamide 6T, polyamide 6T / 66, polyamide 6T / DT, polyamide 66 / 6T / 61, polyamide 66 / 6T, polyamide 6T / 6, polyamide 6T / 6I, polyamide 5T, polyamide 5T / 5I, polyamide 5T / 6T / 5I / 6I, polyamide 5T / 4T / 5I / 4I, polyamide 5T / 510, and mixtures thereof.

[0061] In another preferred embodiment, the semi-crystalline semi-aromatic polyamide is PA4T / 410, PA4T / 4I, PA4T / 6I, PA4T / 10T / 5I / 10I, PA4T / 6T / DT, PA4T / 10T / DT, PA4T / 4I / 6T / 6I / DT / DI, PA5T, PA5T / 5I, PA5T / 6T / 5I / 6I, PA5T / 4T / 5I / 4I, PA5T / 510, PA6T, PA6T / 6, PA6T / 12, PA6T / 6I / 6, PA6T / 6I / 66, PA6T / 66, PA6T / 610, PA6T / 612, PA6T / 1012, PA6T / 6I / 12, PA6T / 8T, PA6T / 9T, PA6T / 10T, PA6T / 10I, PA6T / 12T, PA9T, PA9T / 612, PA9T / 1012, PA10T, PA10T / 106, PA10T / 612, PA10T / 1012, PA10T / 12, PA10T / 11, PA11T, PA12T, and mixtures thereof.

[0062] The semi-crystalline semi-aromatic polyamide can be produced by a conventionally known method such as a melt polymerization method or a solution polymerization method.

[0063] The amount of the semi-crystalline, semi-aromatic polyamide (A) in the present invention is 69% by weight to 89.9% by weight, preferably 70% by weight to 89% by weight, more preferably 72% by weight to 85% by weight, for example, 72% by weight, 75% by weight, 76% by weight, 78% by weight, 79% by weight, 80% by weight, 83% by weight, or 85% by weight, based on the total weight of the insulating coating. Suitable semi-crystalline, semi-aromatic polyamides may be PA9T or copolymers thereof, PA10T or copolymers thereof, PA11T or copolymers thereof, PA12T or copolymers thereof, and mixtures thereof.

[0064] The polyamides disclosed herein should not be limited to those prepared from virgin crude oil monomers, but may also be fully or at least partially biobased or derived from waste streams or recycling activities, i.e., the polyamides used herein can be based on renewable, secondary, or recycled materials. For example, the PA5T, PA6T, PA9T, PA10T, PA11T, and PA12T used herein can be prepared or obtained or derived from monomers obtained in a conventional remonomerization process.

[0065] Preferably, the flame retardant herein is a metal salt of a phosphinic acid of formula (I), a metal salt of a diphosphinic acid of formula (II); [ka] (wherein R1 and R2 are the same or different and are linear or branched C1-C6 alkyl, preferably linear or branched C1-C4 alkyl, more preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl and / or phenyl; M or N is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, a protonated nitrogen base or a mixture thereof, preferably Mg, Ca, Al, Zn, or a mixture thereof, m is an integer from 1 to 4, and n is an integer from 1 to 4; R3 is a straight or branched C1-C 10 Alkylene, C6-C 10 Arylene, C7~C 20 Alkyl arylene or C7-C 20 aryl alkylene, preferably linear or branched C1-C4 alkylene or C6-C 10 arylene, more preferably methylene, ethylene, n-propylene, isopropylene, n-butylene, tert-butylene, n-pentylene, n-octylene, n-dodecylene, phenylene, naphthylene, phenylmethylene, phenylethylene, phenylpropylene, or phenylbutylene). and / or a mixture thereof.

[0066] R4 and R5 are the same or different and are linear or branched C1 to C6 alkyl, preferably linear or branched C1 to C4 alkyl, more preferably methyl, ethyl or propyl; q is an integer of 1 to 4; p is an integer of 1 to 4; and x is an integer of 1 to 4.

[0067] The protonated nitrogen base is preferably a protonated base of ammonia, melamine, triethanolamine, in particular NH4 + is.

[0068] The phosphinic acid for producing the metal salt of the phosphinic acid of the formula (I) in the present invention is preferably dimethylphosphinic acid, ethylmethylphosphinic acid, diethylphosphinic acid, or methyl-n-propylphosphinic acid.

[0069] The diphosphinic acid for producing the salt of diphosphinic acid of formula (II) in the present invention is preferably methane-di(methylphosphinic acid), ethane-1,2-di(methylphosphinic acid), hexane-1,6-di(methylphosphinic acid), benzene-1,4-di(methylphosphinic acid), methylphenylphosphinic acid, or diphenylphosphinic acid.

[0070] Examples of the metal salt of phosphinic acid of formula (I) include calcium dimethylphosphinate, magnesium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, magnesium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, magnesium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate, calcium methyl-n-propylphosphinate, magnesium methyl-n-propylphosphinate, aluminum methyl-n-propylphosphinate, and zinc methyl-n-propylphosphinate. Among these, aluminum diethylphosphinate, zinc diethylphosphinate, aluminum dimethylphosphinate, and zinc dimethylphosphinate are more preferred.

[0071] Examples of metal salts of diphosphinic acids of formula (II) include calcium methane di(methylphosphinate), magnesium methane di(methylphosphinate), aluminum methane di(methylphosphinate), zinc methane di(methylphosphinate), calcium benzene-1,4-(dimethylphosphinate), magnesium benzene-1,4-(dimethylphosphinate), aluminum benzene-1,4-(dimethylphosphinate) and zinc benzene-1,4-(dimethylphosphinate).

[0072] The flame retardant may further comprise a flame retardant synergist (B-2). Suitable flame retardant synergists include phosphorus synergists, nitrogen synergists and phosphorus / nitrogen synergists.

[0073] The phosphorus synergist in the present invention can be a metal salt of phosphorous acid, a polyphosphate, a phosphazene, a polyphosphate, an organophosphate, and mixtures thereof. The metal salt of phosphorous acid has the formula (III) or (IV): [ka] (wherein T is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, a protonated nitrogen base or a mixture thereof, preferably Al and / or Zn; r is 1 to 4; w is 1 to 4; and z is 1 to 7, preferably 1 to 4). Contains structural units of

[0074] Examples of molten salts of phosphorous acid are Al(H2PO3)3, Al2(HPO3)3, Zn(HPO3), Al2(HPO3)3·4H2O and Al(OH)(H2PO3)2·2H2O, preferably Al2(HPO3)3.

[0075] The protonated nitrogen base is preferably a protonated base of ammonia, melamine, triethanolamine, in particular NH4 + is.

[0076] Suitable nitrogen synergists may be melamine condensation products such as melem, melam, melon, and mixtures thereof.

[0077] Suitable phosphorus / nitrogen synergists may be reaction products of melamine and polyphosphoric acid, condensation products of melamine and polyphosphoric acid, and mixtures thereof, such as dimelamine pyrophosphate, melamine polyphosphate, melem polyphosphate, melam polyphosphate, melon polyphosphate, and mixtures thereof.

[0078] The mass ratio of the metal salt of dialkylphosphinate (B-1) to the flame retardant synergist (B-2) is preferably 60:40 to 90:10, more preferably 75:25 to 90:10, for example, 85:15 or 80:20.

[0079] A suitable flame retardant may be Clariant's Exolit® OP series.

[0080] The flame retardant synergist can also be a metal oxide, metal hydroxide, boehmite, hydrotalcite, hydrocalumite, metal borate such as zinc borate, or metal hydroxystannate such as zinc hydroxystannate. Suitable metal oxides are magnesium oxide, calcium oxide, zinc oxide, manganese oxide, tin oxide, tin oxide hydrate, and mixtures thereof. Suitable metal hydroxides are aluminum hydroxide, magnesium hydroxide, calcium hydroxide, zinc hydroxide, and manganese hydroxide.

[0081] In one preferred embodiment, the flame retardant (B) is a mixture of a metal salt of a dialkylphosphinate (B-1) and a metal salt of a phosphorous acid containing structural units of formula (III) or (IV).

[0082] In one preferred embodiment, the flame retardant (B) is a mixture of a metal salt of a dialkylphosphinate (B-1) and a flame retardant synergist (B-2), the metal salt of dialkylphosphinate (B-1) is selected from the group consisting of aluminum diethylphosphinate, zinc diethylphosphinate, aluminum dimethylphosphinate and zinc dimethylphosphinate, preferably aluminum diethylphosphinate; the flame retardant synergist is a metal salt of phosphorous acid containing a structural unit of formula (III) or (IV) selected from the group consisting of Al(H2PO3)3, Al2(HPO3)3, Zn(HPO3), Al2(HPO3)3·4H2O and Al(OH)(H2PO3)2·2H2O, preferably Al2(HPO3)3, The metal salt of phosphinic acid (B-1) and the flame retardant synergist (B-2) are present in a mass ratio of 75:25 to 90:10.

[0083] In one preferred embodiment, the flame retardant (B) is a mixture of a metal salt of a dialkylphosphinate (B-1) and a flame retardant synergist (B-2), the metal salt of dialkylphosphinate (B-1) is at least one selected from the group consisting of aluminum diethylphosphinate, zinc diethylphosphinate, aluminum dimethylphosphinate and zinc dimethylphosphinate, preferably aluminum diethylphosphinate; and the flame retardant synergist (B-2) is at least one selected from the group consisting of melamine polyphosphate, melem polyphosphate, and melam polyphosphate; The metal salt of phosphinic acid (B-1) and the flame retardant synergist (B-2) are present in a mass ratio of 75:25 to 90:10.

[0084] The flame retardant (B) in the present invention is contained in an amount of 10 to 25% by weight, preferably 15 to 25% by weight, for example 15, 20, or 25% by weight, based on the total weight percent of the insulating coating.

[0085] The acid scavenger in the present invention includes metal stannates, metal hydroxystannates, and metal salts of higher fatty acids.

[0086] The term "metal stannate" as used herein excludes partially or fully hydrated metal stannates. Examples of metal stannates are zinc stannate, magnesium stannate, calcium stannate, barium stannate, bismuth stannate, and mixtures thereof, preferably zinc stannate and bismuth stannate.

[0087] Examples of metal hydroxystannates are zinc hydroxystannate, bismuth hydroxystannate, and mixtures thereof.

[0088] Examples of metal salts of higher fatty acids are calcium stearate, zinc stearate, magnesium behenate, magnesium stearate, sodium ricinoleate and potassium palmitate, antimony pyrocatecholate and zinc pyrocatecholate, and mixtures thereof, with zinc stearate, calcium stearate and magnesium stearate being preferred.

[0089] The acid scavenger can also be zinc oxide, calcium lactate, hydrotalcite, dihydrotalcite, and mixtures thereof.

[0090] In a preferred embodiment of the present invention, the acid scavenger is a metal stannate, preferably anhydrous zinc stannate and / or anhydrous bismuth stannate.

[0091] The acid scavenger (C) in the present invention is contained in an amount of 0.1 to 1% by weight, preferably 0.1 to 0.5% by weight, based on the total weight percent of the insulating coating.

[0092] The further additives in the present invention may be selected from conventional additives for plastics, such as lubricants, antioxidants, mold release agents, impact modifiers, heat stabilizers, light stabilizers, e.g., UV stabilizers, plasticizers, surfactants, nucleating agents, coupling agents, antibacterial agents, antistatic agents, and any combination thereof.

[0093] For purposes of the present invention, additives may be used in conventional amounts, for example, the insulating coating may include at least one additive in an amount of 0.01 to 5 weight percent, based on the total weight percent of the insulating coating.

[0094] The insulating coating may contain, for example, an antioxidant. Suitable antioxidants are aromatic amine-based antioxidants, hindered phenol-based antioxidants, and phosphite-based antioxidants, in particular hindered phenol-based antioxidants. Examples of the hindered phenolic antioxidant include, but are not limited to, α-[3-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1-oxopropyl]-ω-[3-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1-oxopropoxy]poly(oxy-1,2-ethanediyl), 2,4-bis[(octylthio)methyl]-o-cresol, octyl-3,5-di-tert-butyl-4-hydroxy-hydrocinnamate, 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid C7-C9 branched alkyl ester, 2,4-bis[(dodecylthio)methyl]-o-cresol, 4,4′-butylidenebis-(3-methyl-6-tert-butylphenol), 3,5-bis(1,1-dimethylethyl)- 4-Hydroxybenzenepropanoic acid octadecyl ester, pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydrophenyl)propionate], 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine, tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, and 2,2-thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-1,6-hexanediylbis[3,5-bis(1,1-dimethylethyl)-4-hydroxyl-benzenepropanamide].

[0095] When present, the antioxidant may be in an amount of 0.01 to 1 weight percent, or 0.1 to 0.5 weight percent, based on the total weight percent of the insulating coating.

[0096] The insulating coating may contain, for example, a heat stabilizer. Suitable heat stabilizers include organic phosphinates, inorganic hypophosphites, inorganic phosphonates, organic phosphinates, and mixtures thereof, with inorganic phosphonates and organic phosphinates being preferred. Examples of heat stabilizers include sodium phosphonate, potassium phosphonate, sodium phenylphosphonate, potassium phenylphosphonate, lithium phenylphosphonate, sodium ethylphosphonate, potassium ethylphosphonate, ammonium phosphonate, sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, magnesium hypophosphite, calcium hypophosphite, ammonium hypophosphite, sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, magnesium hypophosphite, calcium hypophosphite, ammonium hypophosphite, and sodium benzenephosphinate.

[0097] Suitable heat stabilizers are halogen-containing compounds, preferably metal halides, more preferably KCl, KBr, KI and CuI, most preferably a mixture of KI and CuI.

[0098] The insulating coating can include, for example, a lubricant. Suitable lubricants are preferably esters or amides of saturated or unsaturated aliphatic carboxylic acids having 10 to 40, preferably 16 to 22, carbon atoms with saturated aliphatic alcohols or amines having 2 to 40, preferably 2 to 6, carbon atoms. The carboxylic acids can be monobasic or dibasic. Examples of carboxylic acids include pelargonic acid, palmitic acid, lauric acid, margaric acid, dodecanedioic acid, and behenic acid, with stearic acid, capric acid, and montanic acid (a mixture of fatty acids having 30 to 40 carbon atoms). The fatty alcohols can be monohydric to tetrahydric. Examples of fatty alcohols include n-butanol, n-octanol, stearyl alcohol, ethylene glycol, propylene glycol, neopentyl glycol, and pentaerythritol, with glycerol and pentaerythritol being preferred. The fatty amines can be monofunctional to trifunctional. Examples of aliphatic amines are stearylamine, ethylenediamine, propylenediamine, hexamethylenediamine and di(6-aminohexyl)amine, with ethylenediamine and hexamethylenediamine being particularly preferred.

[0099] Preferred esters or amides are N,N'-ethylenedi(stearamide), glycerol distearate, glycerol tristearate, glycerol monopalmitate, glycerol trilaurate, glycerol monobehenate, and pentaerythritol tetrastearate. N,N'-ethylenedi(stearamide) is particularly preferred as a lubricant in the insulating coating according to the present invention.

[0100] It is also possible to use mixtures of different esters or amides, or combinations of esters with amides in any desired mixing ratio.

[0101] Other lubricants are preferably long-chain fatty acids (e.g., stearic acid or behenic acid), salts thereof (e.g., calcium stearate or zinc stearate), or montan wax (a mixture of linear saturated carboxylic acids with a chain length of 28 to 32 carbon atoms), calcium montanate or sodium montanate, and also low molecular weight polyethylene waxes and low molecular weight polypropylene waxes.

[0102] When present, the lubricant may be in an amount of 0.01 to 2 weight percent, or 0.2 to 1 weight percent, based on the total weight percent of the insulating coating.

[0103] The insulating coating may include, for example, an impact modifier. Suitable impact modifiers may include polyolefin-based, styrene-based, and unsaturated carboxylic acid-based impact modifiers. Suitable impact modifiers may also be modified with functional blocks such as epoxy functional blocks and / or acid anhydride blocks. The epoxy functional blocks may be units derived from glycidyl (meth)acrylate. The acid anhydride blocks may be units derived from maleic anhydride.

[0104] Suitable polyolefin impact modifiers can include polyolefins containing repeating units derived from olefins having from 2 to 10 carbon atoms. Examples of such olefins include ethylene, 1-butene, 1-propylene, 1-pentene, 1-octene, and mixtures of ethylene and 1-octene, preferably ethylene, 1-propylene, and mixtures of ethylene and 1-octene.

[0105] Suitable unsaturated carboxylic acid impact modifiers may include blocks derived from carboxylic acids and their derivatives, such as esters, imides, and amides. Suitable carboxylic acids and their derivatives include, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, glutaconic acid, itaconic acid, citraconic acid, (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (methyl)acrylate, and isobutyl (meth)acrylate.

[0106] The impact modifier may also be a bipolymer or terpolymer or a core-shell structured polymer. Examples of such impact modifiers include styrene / ethylene / butylene copolymer (SEBS), ethylene-methyl acrylate-glycidyl methacrylate terpolymer, ethylene / propylene / diene rubber (EPDM), and ethylene-octene copolymer.

[0107] When present, the impact modifier may be in an amount of 0.01 to 5 weight percent, or 1 to 5 weight percent, based on the total weight percent of the insulating coating.

[0108] The insulating coating may include plasticizers, including, for example, but not limited to, dioctyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, hydrocarbon oils, and N-(n-butyl)benzenesulfonamide.

[0109] When present, the plasticizer may be in an amount of 0.01 to 5 weight percent, or 1 to 5 weight percent, based on the total weight percent of the insulating coating.

[0110] The insulating coating may contain, for example, a nucleating agent that, when used in small amounts, does not deteriorate the physical properties of the molded article and has a significant effect in promoting crystallization.

[0111] The nucleating agent herein can be selected from at least one of inorganic nucleating agents having a particle size of less than 1 μm and organic nucleating agents. Preferably, the inorganic nucleating agent is at least one of talc powder, montmorillonite, and calcium carbonate, and the organic nucleating agent is at least one of sodium benzoate, sorbitol dibenzyl ester, and sodium carboxylate.

[0112] The nucleating agent, if present, may be in an amount of 0.01 to 5 weight percent, or 1 to 5 weight percent, based on the total weight percent of the insulating coating.

[0113] The insulating coating of the present invention is a coating or a thin sheet, and the thickness can be adjusted based on the application requirements, preferably in the range of 50 μm to 600 μm, more preferably in the range of 100 μm to 400 μm, and most preferably in the range of 150 μm to 300 μm.

[0114] The insulating coating of the present invention exhibits excellent flame retardancy approaching V-0 UL94 VTM for a 0.20 mm thick test piece and V-0 UL94 for a 0.8 mm thick test piece.

[0115] The insulating coating of the present invention is capable of passing the GWFI (Glow Wire Flammability Index) test according to DIN EN 60695-2-12 at 960°C on test specimens with thicknesses of 0.75 mm and 1.5 mm.

[0116] The insulating coating of the present invention is capable of passing the GWIT (glow wire ignition temperature) test according to DIN EN 60695-2-13 at 775°C on a test piece having a thickness of 0.75 mm.

[0117] The insulating coating of the present invention has a dielectric strength of more than 40 KV / mm, preferably more than 45 KV / mm, measured in a conditioned state at room temperature in Midel 7131 ester solution according to IEC 60243-1.

[0118] The insulating coating of the present invention has a dielectric strength of greater than 70 KV / mm, preferably greater than 72 KV / mm, measured in a dry state at room temperature in Midel 7131 ester solution according to IEC 60243-1.

[0119] The insulating coating of the present invention has a dielectric strength of more than 40 KV / mm, preferably more than 45 KV / mm, measured in a dry state at 150° C. in Midel 7131 ester solution according to IEC 60243-1.

[0120] The insulating coating of the present invention has a dielectric strength loss of 40% or less, preferably 35%, at 120°C compared to the dielectric strength measured in a dry state at room temperature in Midel 7131 ester solution according to IEC 60243-1.

[0121] The insulating coating of the present invention has a dielectric strength loss of 45% or less, preferably 37%, at 150°C compared to the dielectric strength measured in a dry state at room temperature in Midel 7131 ester solution according to IEC 60243-1.

[0122] The surface of the insulating coating of the present invention is flat, smooth and uniform, and is free from defects such as silver spots, burrs and cracks.

[0123] Therefore, the present invention provides a coil bobbin comprising the insulating coating of the present invention.

[0124] the present invention further provides uses of the insulating coating, which can be used in the following fields: packaging; electrical insulating materials for motors, transformers, cables, etc.; dielectric materials for capacitors, etc.; magnetic tape materials such as magnetic tape cassettes, magnetic tapes for digital data storage, and video tapes; protective sheets for solar cell substrates, liquid crystal panels, display devices, etc.; electronic substrate materials such as LED mounting substrates, flexible printed wiring boards, and flexible flat cables; heat-resistant tapes such as cover lay films for flexible printed wiring, heat-resistant masking tape, and industrial process tape; heat-resistant barcode labels; heat-resistant reflectors; insulating tape; various release films; heat-resistant base films; photographic films; molding materials; agricultural materials; medical materials; civil engineering and construction materials; membranes for household use such as filtration membranes, and industrial materials.

[0125] Therefore, the present invention provides a method for producing the insulating coating of the present invention, which includes the step (S1) of heating granules prepared from a polyamide-based composition having the same components as the insulating coating and melt-extruding the granules through a slit die to form an extruded layer, and cooling the extruded layer to obtain an insulating coating or an unstretched coating.

[0126] In a preferred embodiment of the present invention, the production method includes a step (S2) of stretching the unstretched film to form an insulating film.

[0127] In a preferred embodiment of the present invention, the manufacturing method includes a step (S3) of heat setting and cooling to obtain an insulating coating.

[0128] In a more preferred embodiment of the present invention, the method of manufacture comprises: (S1) a step of heating granules prepared from a polyamide-based composition having the same components as the insulating coating, melt-extruding the granules through a slit die to form an extruded layer, and cooling the extruded layer to obtain an insulating coating or an unstretched coating; (S2) A step of stretching the unstretched film to form an insulating film. Includes.

[0129] In a more preferred embodiment of the present invention, the method of manufacture comprises: (S1) a step of heating granules prepared from a polyamide-based composition having the same components as the insulating coating, melt-extruding the granules through a slit die to form an extruded layer, and cooling the extruded layer to obtain an insulating coating or an unstretched coating; (S2) stretching the unstretched film to form an insulating film; (S3) heat fixing and cooling to obtain an insulating film; Includes.

[0130] The granules are prepared according to conventional methods. For example, the individual components of the insulating coating according to the present invention can be mixed and then shaped to form an article by injection and / or extrusion in conventional mixing equipment, such as a screw extruder, a Brabender mixer, or a Banbury mixer. The mixing or extrusion temperature used herein is generally 280°C to 330°C.

[0131] Regarding step (S1), the granules are preferably melted at a temperature of 280 to 340°C and then screw-extruded into a layer or film having a thickness of 50 to 600 μm. The screw rotation speed is not limited in the present invention and is, for example, 30 to 80 rpm. Chill roll: 100 to 180°C. Cooling can be achieved by conventional methods, for example, via a chill roll. The chill roll temperature is preferably 110 to 170°C.

[0132] The stretching in step (S2) can be carried out by a conventional method.

[0133] In a preferred embodiment of the present invention, in the process of step (S2), the unstretched film is stretched in the longitudinal direction by 0 to 3 times, more preferably by 0.1 to 1.5 times.

[0134] In a preferred embodiment of the present invention, the unstretched film is stretched at a temperature of 125°C to 180°C.

[0135] In a preferred embodiment of the present invention, after the insulating coating is obtained, it is peeled off from the roll at a speed of preferably 1 m / min to 15 m / min, more preferably 2 m / min to 8 m / min. [Example]

[0136] The following examples further illustrate aspects of the present invention; these examples are provided to illustrate certain aspects of the invention and should not be construed as limiting thereof.

[0137] The following materials and test methods were used in the examples.

[0138] material: [Table 1]

[0139] General specimen preparation procedure Granulation preparation: Naturally colored polyamide 9T was dried at 120°C until the moisture content was less than 0.1% by weight, and all other components (C) and (D) were premixed in a tumble mixer for 10 minutes. In the next step, the dried polyamide 9T was melt-extruded with the dried compounding components using a twin-screw extruder with a diameter of 26 mm and an L / D ratio of 44. Flame retardant (B) was added to the polymer melt via a side feeder. The extruder was operated with a flat temperature profile at a rotation speed of 350 rpm, a throughput of 30 kg / h, and a barrel temperature of 280°C to 330°C. The resulting strands were cooled in a water bath and pelletized.

[0140] Preparation of the insulating coating: The obtained granules were heated and melt-extruded through a slit die, and a film having a thickness of 240 μm was produced using a single-screw extruder (rotation speed: 50 rpm, flat temperature profile: 340°C, cooling roll: 140°C, peeling speed: 4.8 m / min).

[0141] measurement: Test specimens for the tests listed in Table 2 were injection molded in an Arburg 420C injection molding machine at a melt temperature of about 340°C and a mold temperature of about 80°C.

[0142] 1. The tensile modulus, tensile strength, and elongation at break of 4 mm thick test specimens were measured in accordance with ISO 527-2-1993. Type 1 test specimens described in ISO 527-2-1993 were used. Charpy notched impact strength and Charpy unnotched impact strength were measured in accordance with ISO 179-2 / 1eA. All test specimens were conditioned at 23°C and 50% relative humidity for 24 hours. Testing was performed in the same atmosphere as the conditioning.

[0143] 2. Melt volume flow rate (MVR) was tested according to ISO1133 at 325°C and a load of 5 kg.

[0144] 3. Viscosity number was determined according to ISO 307 as a 0.5 wt% solution in 96 wt% sulfuric acid at 25°C.

[0145] 4. Flammability was determined according to UL 94 V method (Underwriters Laboratories Inc. Standard of Safety, "Test for Flammability of Plastic Materials for Parts in Devices and Appliances", p.14-p.18 Northbrook 1998).

[0146] 5. The Glow-Wire Flammability Index (GWFI) was tested on plaques according to DIN EN 60695-2-12. The GWFI test is a general suitability test for plastics in contact with parts carrying electrical potential. The temperature determined is the highest temperature at which one of the following conditions is met in three consecutive tests: (a) no ignition of the test specimen, or (b) an afterflame or glow time of 30 seconds after the end of exposure to the glow-wire and no ignition of the substrate.

[0147] 6. The glow-wire ignition temperature (GWIT) was tested on plaques according to DIN EN 60695-2-13. In the GWIT test, the maximum temperature is determined for three specimens (e.g., on a plate with a geometry of 60 x 60 x 1.5 mm) using a glow-wire at temperatures between 650 and 960 °C, and the exposure time of the glow-wire does not lead to ignition. The specified glow-wire ignition temperature exceeds the determined maximum temperature by 25 K. The criterion for ignition is a flame with a burning time of more than 5 seconds.

[0148] 7. Volume resistivity was measured in accordance with IEC 62631-3-1.8. Dielectric strength was measured in accordance with IEC 60243-1 in Midel 7131 ester fluid. Midel 7131 is a biodegradable synthetic ester dielectric fluid designed to provide an alternative to mineral oil, silicone fluids, and dry-type transformers. 20mm diameter ball / ball electrode. Voltage slew rate = 2.0kV / s.

[0149] [Table 2]

[0150] [Table 3]

[0151] The results in Table 3 show that the insulating coating of Ex. 1 (i.e., the N4U41 coating) prepared using the polyamide-based composition of the present invention exhibits a significant increase in dielectric strength at a relatively thin thickness and excellent flame retardancy compared to the T410 coating of Comp. 1. Considering that the cost of the T410 coating of Comp. 1 is much higher than the cost of the N4U41 coating of Ex. 1, the present invention provides an effective method for obtaining an insulating coating with excellent dielectric strength, high volume resistivity, and outstanding flame retardancy.

[0152] [Table 4]

[0153] Surprisingly, the results in Table 4 show that, although the insulating coating prepared using the polyamide-based composition of the present invention exhibits a relatively high dielectric strength (i.e., 46 kV / mm) at a high temperature of 150°C, the decrease in dielectric strength at 150°C is only about 37% compared to the dielectric strength measured in a dry state at room temperature (i.e., 23°C) in a Midel 7131 ester solution according to IEC 60243-1. In addition, the dielectric strength of the insulating coating at 120°C can remain above 45 (i.e., 48), despite a decrease of about 34% compared to the dielectric strength measured in a dry state at room temperature (i.e., 23°C). Thus, the insulating coating provided by the present invention exhibits a relatively small decrease in dielectric strength in response to increasing temperature and, therefore, excellent dielectric strength stability when exposed to significantly elevated temperatures.

[0154] [Table 5]

[0155] Furthermore, it is surprising to see from the results in Table 5 that the insulating coating prepared using the polyamide-based composition of the present invention exhibits high volume resistivity at room temperature. Even at a high temperature of 150°C, the volume resistivity can still remain at 3.1E+09 Ohm*cm, proving that the insulating coating still has improved electrical insulating properties at high temperatures.

[0156] [Table 6]

[0157] The insulating coatings produced by the examples of the above polyamide-based compositions shown in Table 6 can approach V-0 UL94 VTM for 0.2 mm thick specimens, V-0 UL94 for 0.8 mm thick specimens, and V-2 UL94 for 0.4 mm thick specimens, and also show excellent flame retardancy, passing the GWFI (Glow Wire Flammability Index) test according to DIN EN 60695-2-12 at 960°C for 0.75 mm and 1.5 mm thick specimens.

[0158] With regard to insulating properties, the insulating coatings produced in Examples 2-3 have excellent dielectric strength exceeding 40 KV / mm at room temperature, and also exhibit excellent dielectric strength stability, with a dielectric strength decrease of 45% or less at 150°C compared to the dielectric strength measured in a dry state at room temperature in Midel 7131 ester solution according to IEC 60243-1.

[0159] Furthermore, the mechanical properties of the insulating coating prepared using the polyamide-based composition of the present invention can meet the requirements for use in various technical fields, particularly in electrical and electronic systems, new energy vehicles, electrical insulating materials for motors (motor coil bobbins are provided with insulating coatings), packaging, and heat-resistant materials.

[0160] It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the scope and spirit of the invention. It is intended that the embodiments and examples be considered merely as illustrative. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.

Claims

1. An insulating coating prepared from a polyamide-based composition, A) 69 to 89.9 wt. % of a polyamide; B) 10 to 25 wt. % of a flame retardant; C) 0.1 to 1.0 wt % of an acid scavenger; D) 0 to 5 wt. % of further additives; wherein the total weight percent of components A) through D) is 100%.

2. 10. The insulating coating of claim 1, wherein the polyamide comprises at least one semi-crystalline, semi-aromatic polyamide comprising dicarboxylic acid units, diamine units, and optionally units derived from other monomers such as amino acids and / or lactam units, wherein the dicarboxylic acid units or diamine units bear aromatic groups.

3. 3. The insulating coating of claim 2, wherein the semi-crystalline, semi-aromatic polyamide comprises aromatic dicarboxylic acid units and aliphatic diamine units, or aliphatic and / or alicyclic dicarboxylic acid units and aromatic diamine units.

4. The semi-crystalline semi-aromatic polyamide is PA4T / 410, PA4T / 4I, PA4T / 6I, PA4T / 10T / 5I / 10I, PA4T / 6T / DT, PA4T / 10T / DT, PA4T / 4I / 6T / 6I / DT / DI, PA5T, PA 5T / 5I, PA5T / 6T / 5I / 6I, PA5T / 4T / 5I / 4I, PA5T / 510, PA6T, PA6T / 6, PA6T / 12, PA6T / 6I / 6, PA6T / 6I / 66, PA6T / 66, PA6T / 610, PA6T / 612 4. The insulating coating according to claim 1, wherein the insulating coating is at least one selected from the group consisting of PA6T / 1012, PA6T / 6I / 12, PA6T / 8T, PA6T / 9T, PA6T / 10T, PA6T / 10I, PA6T / 12T, PA9T, PA9T / 612, PA9T / 1012, PA10T, PA10T / 106, PA10T / 612, PA10T / 1012, PA10T / 12, PA10T / 11, PA11T, PA12T, or any combination thereof.

5. The flame retardant is a metal salt of a phosphinic acid of formula (I), a metal salt of a diphosphinic acid of formula (II); 【Chemical 1】 (In the formula, R １ and R ２ are the same or different, and are linear or branched C １ ~C ６ alkyl, preferably straight-chain or branched C １ ~C ４ alkyl, more preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl and / or phenyl; M or N is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, a protonated nitrogen base or a mixture thereof, preferably Mg, Ca, Al, Zn, or a mixture thereof, m is an integer from 1 to 4, and n is an integer from 1 to 4; R ３ is a straight or branched C １ ~C １０ Alkylene, C ６ ~C １０ Arylene, C ７ ~C ２０ Alkylarylene or C ７ ~C ２０ aryl alkylene, preferably linear or branched C １ ~C ４ Alkylene or C ６ ~C １０ arylene, more preferably methylene, ethylene, n-propylene, isopropylene, n-butylene, tert-butylene, n-pentylene, n-octylene, n-dodecylene, phenylene, naphthylene, phenylmethylene, phenylethylene, phenylpropylene or phenylbutylene; R ４ and R ５ are the same or different, and are linear or branched C １ ~C ６ alkyl, preferably straight-chain or branched C １ ~C ４ alkyl, more preferably methyl, ethyl or propyl; q is an integer of 1 to 4; p is an integer of 1 to 4; and x is an integer of 1 to 4. The insulating coating according to any one of claims 1 to 4, comprising (B-1) a metal salt of dialkylphosphinate containing a metal salt of dialkylphosphinate or a mixture thereof.

6. 6. The insulating coating according to claim 5, wherein the flame retardant further comprises a flame retardant synergist (B-2) that is at least one selected from the group consisting of a phosphorus synergist, a nitrogen synergist, and / or a phosphorus / nitrogen synergist.

7. 7. The insulating coating according to claim 1, wherein the acid scavenger comprises at least one selected from the group consisting of metal stannates, metal hydroxystannates, metal salts of higher fatty acids, or any combination thereof.

8. 8. The insulating coating of claim 1, wherein the further additive can be at least one selected from the group consisting of a lubricant, an antioxidant, a release agent, an impact modifier, a heat stabilizer, a light stabilizer, a plasticizer, a surfactant, a nucleating agent, a coupling agent, an antibacterial agent, an antistatic agent, and any combination thereof.

9. 9. An insulating coating according to any one of claims 1 to 8, wherein the coating has a thickness in the range of 50 μm to 600 μm, more preferably in the range of 100 μm to 400 μm, and most preferably in the range of 150 μm to 300 μm.

10. 10. The insulating coating according to claim 1, wherein the dielectric strength measured in a conditioned state at room temperature in a Midel 7131 ester solution in accordance with IEC 60243-1 exceeds 40 KV / mm.

11. 10. The insulating coating according to claim 1, wherein the dielectric strength measured in a dry state at room temperature in a Midel 7131 ester solution in accordance with IEC 60243-1 exceeds 70 KV / mm.

12. 10. The insulating coating according to claim 1, wherein the dielectric strength measured in a dry state in Midel 7131 ester fluid at 150°C in accordance with IEC 60243-1 exceeds 40 KV / mm.

13. 13. The insulating coating according to claim 1, which has a dielectric strength loss of 45% or less at 150°C in Midel 7131 ester fluid compared to the dielectric strength measured in a dry state at room temperature in accordance with IEC 60243-1.

14. Use of a polyamide-based composition in the preparation of an insulating coating, the insulating coating comprising: A) 69 to 89.9 wt. % of a polyamide; B) 10 to 25 wt. % of a flame retardant; C) 0.1 to 1.0 wt % of an acid scavenger; D) 0 to 5 wt. % of further additives; wherein the total weight percentage of components A) to D) is 100%.

15. The use according to claim 12, wherein granules prepared from a polyamide-based composition having the same components as the insulating coating are extruded and cooled to obtain the insulating coating or the unstretched coating.

16. The use according to any one of claims 13, wherein the unstretched film is stretched to form an insulating film.

17. The use according to any one of claims 13 to 14, wherein the unstretched film is stretched, heat-set and cooled to obtain an insulating film.

18. Use according to any one of claims 13 to 15, wherein the granules are melted, preferably at a temperature of 280 to 340°C, and then screw extruded into a film having a thickness of 50 to 600 µm.

19. 12. Use of the insulating coating according to any one of claims 1 to 11 for manufacturing components of electrical insulating parts for electric and electronic systems, new energy vehicles, and motors.

Images