Semi-aromatic polyamide composition, semi-aromatic polyamide film and production method therefor, electronic material, optical component, and solar power generation module

Abstract

A purpose of the present invention is to provide a semi-aromatic polyamide composition which is less apt to form a gel-state substance therein during melt extrusion. Another purpose is to provide a semi-aromatic polyamide film obtained from the semi-aromatic polyamide composition, the semi-aromatic polyamide film having a low yellowness and high breaking resistance, being less apt to thermally shrink in high-temperature atmospheres, and having high moist-heat resistance in high-temperature high-humidity atmospheres. This semi-aromatic polyamide composition comprises a semi-aromatic polyamide, a heat stabilizer based on a hindered phenol, and a heat stabilizer based on a hindered amine.

Description

Semi-aromatic polyamide compositions, semi-aromatic polyamide films and methods for producing the same, electronic materials, optical components, and photovoltaic modules.

[0001] The present invention relates to a semi-aromatic polyamide composition, a semi-aromatic polyamide film and a method for producing the same, electronic materials, optical components, and photovoltaic modules.

[0002] Semi-aromatic polyamide films are made by forming semi-aromatic polyamide compositions into thin films. They are highly heat-resistant and lightweight, and are therefore used in a wide range of fields, including displays, semiconductors, automobiles, and environment / energy.

[0003] Among these applications, for example, the base film used in LED displays requires dimensional stability at high temperatures to withstand solder reflow during circuit formation. Therefore, semi-aromatic polyamides with high melting points are preferably used as the resin component of the base film. Furthermore, semi-aromatic polyamide films used as base films, etc., require resistance to humidity and heat to improve their service life when used outdoors. In particular, semi-aromatic polyamide films used in outdoor display materials, solar power generation materials, electrical insulation materials, automotive materials, and building materials require high resistance to humidity and heat.

[0004] Long-term reliability evaluations for outdoor use vary depending on the requirements, but commonly employed methods include durability tests in an environment of 85°C and 85% humidity, and pressure cooker tests in an environment of 121°C and 100% humidity.

[0005] On the other hand, semi-aromatic polyamides with high heat resistance, such as those with a melting point exceeding 300°C, have very close melting points and thermal decomposition temperatures. As a result, crosslinking and degradation are likely to occur due to decomposition reactions during melt processing. Consequently, insoluble or infusible gel-like substances are formed in the polymer, impairing the quality of the film. Alternatively, when removing these gel-like substances with filters, the filters become clogged, making it difficult to manufacture films by continuous extrusion over long periods.

[0006] Patent Document 1 discloses a technique for improving hydrolysis resistance by reducing the amount of terminal carboxyl groups in a biaxially oriented polyester film. However, it does not consider processing suitability at high temperatures of 250°C or higher, such as reflow solder resistance. Patent Document 2 discloses a technique for improving heat and moisture resistance by using a PEN film with EVA as an interlayer adhesive as a protective sheet for solar cell modules. However, this document also does not consider how to achieve both processing suitability at high temperatures of 250°C or higher and heat and moisture resistance under outdoor exposure.

[0007] Japanese Patent Publication No. 2015-145460 Japanese Patent Publication No. 2011-124428

[0008] The present invention has been made in view of the above circumstances and aims to provide a semi-aromatic polyamide composition that does not easily produce gel-like material during melt extrusion. The present invention also aims to provide a semi-aromatic polyamide film obtained from the above semi-aromatic polyamide composition that has low yellowness, high fracture resistance, is less susceptible to thermal shrinkage in high-temperature atmospheres, and has high heat and humidity resistance in high-temperature and high-humidity atmospheres.

[0009] The present invention provides the following embodiments: <1> A semi-aromatic polyamide composition containing a semi-aromatic polyamide, a hindered phenol-based heat stabilizer, and a hindered amine-based heat stabilizer. <2> The semi-aromatic polyamide composition according to <1>, wherein the content of the hindered phenol-based heat stabilizer is 0.5 to 10 parts by mass per 1 part by mass of the hindered amine-based heat stabilizer. <3> The semi-aromatic polyamide composition according to <1> or <2>, wherein the content of the hindered phenol-based heat stabilizer is 0.1 to 1.5% by mass. <4> The semi-aromatic polyamide composition according to any one of <1> to <3>, wherein the semi-aromatic polyamide is at least one selected from the group consisting of polyamide 6T, polyamide 9T, polyamide 10T, and polyamide 9N. <5> A semi-aromatic polyamide film obtained from the semi-aromatic polyamide composition according to any one of <1> to <4>. <6> The following physical properties (1) to (4): (1) The thermal shrinkage rate S in the longitudinal direction of the film, which is determined by measuring the dimensions after heat treatment in an atmosphere of 250°C for 5 minutes, and then leaving it at a temperature of 23°C and humidity of 50% RH for 2 hours. MD and thermal shrinkage coefficient S in the width direction TDThe semi-aromatic polyamide film described in <5> satisfies all of the following conditions: (1) The respective values ​​are -1.0 to 1.5%; (2) The retention rate of the tensile break elongation in the longitudinal and width directions of the film after moist heat treatment for 120 hours at a temperature of 121°C and a humidity of 100% RH is 80% or more; (3) The yellowness (YI) is 10 or less in absolute value; (4) The tensile break strength in the longitudinal and width directions of the film is 150 MPa or more. <7> An electronic material having the semi-aromatic polyamide film described in <5> or <6>. <8> An optical component having the semi-aromatic polyamide film described in <5> or <6>. <9> A photovoltaic module having the semi-aromatic polyamide film described in <5> or <6>. <10> A method for producing a semi-aromatic polyamide film according to <5> or <6>, comprising the steps of: obtaining an unstretched film from the semi-aromatic polyamide composition according to <1>; stretching the unstretched film to obtain a stretched film; and subjecting the stretched film to a heat-fixing treatment at a temperature of the melting point (Tm) of the semi-aromatic polyamide - (10 to 22°C). <11> The method for producing a semi-aromatic polyamide film according to <10>, comprising the step of subjecting the stretched film that has undergone heat-fixing treatment to a relaxation treatment.

[0010] The semi-aromatic polyamide composition of the present invention contains a hindered phenol-based heat stabilizer and a hindered amine-based heat stabilizer, thereby effectively suppressing the formation of gel-like material during melt extrusion. This not only allows for the production of high-quality semi-aromatic polyamide films, but also reduces clogging of filters when removing gel-like material, enabling film production through long-term continuous extrusion.

[0011] Furthermore, the semi-aromatic polyamide film of the present invention exhibits excellent dimensional stability in high-temperature environments because it is less susceptible to thermal shrinkage in high-temperature environments, and it also has high heat and moisture resistance in high-temperature and high-humidity environments, thus maintaining excellent mechanical properties even in such environments. Moreover, the semi-aromatic polyamide film of the present invention has high tensile strength, resulting in high fracture resistance, and low yellowness, resulting in high transparency and achromaticity.

[0012] Because the semi-aromatic polyamide film of the present invention has the above-mentioned characteristics, it can be suitably used, for example, as a film used in solar cells such as perovskite type, an optical film used as a substrate for display materials, a film used in transparent antennas and sensors, and a heat-resistant tape.

[0013] 1. Semi-aromatic polyamide composition The semi-aromatic polyamide composition of the present invention contains a semi-aromatic polyamide, a hindered phenol-based heat stabilizer, and a hindered amine-based heat stabilizer. The semi-aromatic polyamide composition of the present invention will be described in detail below.

[0014] <Semi-aromatic polyamide> A semi-aromatic polyamide is a resin obtained by a dehydration condensation reaction between a dicarboxylic acid component and a diamine component, and has at least repeating units derived from the dicarboxylic acid component and repeating units derived from the diamine component. Furthermore, a semi-aromatic polyamide contains an aromatic compound in either the dicarboxylic acid component or the diamine component. A semi-aromatic polyamide may contain one type of compound, or two or more types of compounds.

[0015] Examples of dicarboxylic acid components include aliphatic dicarboxylic acids and aromatic dicarboxylic acids.

[0016] Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanediic acid, tetradecanediic acid, and octadecanediic acid. These may be used individually or in combination of two or more.

[0017] Examples of aromatic dicarboxylic acids include terephthalic acid (TPA), isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, and 4,4'-diphenyl etherdicarboxylic acid. These may be used individually or in combination of two or more.

[0018] Examples of naphthalenedicarboxylic acids include 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid. Examples of diphenyldicarboxylic acids include 4,4'-diphenyldicarboxylic acid, 3,3'-diphenyldicarboxylic acid, and 2,2'-diphenyldicarboxylic acid. These may be used individually or in combination of two or more.

[0019] Examples of diamine components include aliphatic diamines, alicyclic diamines, and aromatic diamines.

[0020] Examples of aliphatic diamines include linear aliphatic diamines such as 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine (NDA), 1,10-decanediamine (DDA), 1,11-undecanediamine, and 1,12-dodecanediamine; and branched aliphatic diamines such as 2-methyl-1,8-octanediamine (MODA), 4-methyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine, 2,2,4(2,4,4)-trimethyl-1,6-hexanediamine, 2-methyl-1,5-pentanediamine, 2-methyl-1,6-hexanediamine, and 2-methyl-1,7-heptanediamine. These may be used individually or in combination of two or more.

[0021] Examples of alicyclic diamines include isophorone diamine, norbornane dimethylamine, and tricyclodecane dimethylamine. These may be used individually or in combination of two or more.

[0022] Examples of aromatic diamines include metaxylylenediamine, p-xylylenediamine, m-phenylenediamine, and p-phenylenediamine. These may be used individually or in combination of two or more.

[0023] From the viewpoint of obtaining a semi-aromatic polyamide film that is excellent in dimensional stability under high temperature atmospheres, heat and humidity resistance under high temperature and high humidity atmospheres, transparency, and achromaticity, it is preferable that the dicarboxylic acid component contains an aromatic dicarboxylic acid, more preferably terephthalic acid and / or naphthalenedicarboxylic acid, and even more preferably terephthalic acid.

[0024] The proportion of terephthalic acid and / or naphthalenedicarboxylic acid (the total proportion if two or more are included) in the total amount of dicarboxylic acid components is preferably 60 mol% or more, more preferably 70 mol% or more, and even more preferably 85 mol% or more, from the viewpoint of obtaining a semi-aromatic polyamide film that has excellent dimensional stability in a high-temperature atmosphere, excellent heat resistance in a high-temperature and high-humidity atmosphere, low water absorption, and excellent water resistance.

[0025] From the viewpoint of obtaining a semi-aromatic polyamide film with excellent dimensional stability in high-temperature atmospheres, heat and humidity resistance in high-temperature and high-humidity atmospheres, transparency, and achromaticity, the diamine component preferably contains an aliphatic diamine, and more preferably contains an aliphatic diamine having 6 to 12 carbon atoms. The number of carbon atoms of the aliphatic diamine is preferably 7 or more, more preferably 8 or more, even more preferably 9 or more, and also preferably 11 or less, even more preferably 10 or less. Specifically, the number of carbon atoms of the aliphatic diamine is preferably 7 to 12, more preferably 8 to 12, even more preferably 9 to 12, even more preferably 9 to 11, particularly preferably 9 or 10, and most preferably 9.

[0026] The proportion of aliphatic diamine (preferably an aliphatic diamine having 6 to 12 carbon atoms) in the total amount of diamine components (when two or more are contained, the total proportion) is preferably 60 mol% or more, more preferably 75 mol% or more, still more preferably 90 mol% or more, from the viewpoint of obtaining a semi-aromatic polyamide film excellent in dimensional stability in a high-temperature atmosphere, heat and humidity resistance in a high-temperature and high-humidity atmosphere, transparency, and achromaticity.

[0027] From the viewpoint of obtaining a semi-aromatic polyamide film excellent in dimensional stability in a high-temperature atmosphere, heat and humidity resistance in a high-temperature and high-humidity atmosphere, transparency, and achromaticity, a compound having a repeating unit represented by the following formula (pa-1) is preferable for the semi-aromatic polyamide. (In formula (pa-1), R is a divalent hydrocarbon group containing an aromatic hydrocarbon ring, and n is an integer of 1 or more.)

[0028] Examples of the aromatic hydrocarbon ring include aromatic hydrocarbon rings having 6 to 12 carbon atoms such as a benzene ring and a naphthalene ring.

[0029] The aromatic hydrocarbon ring may have a substituent. Examples of the substituent include a halogen atom, an oxo group, a hydroxy group, a substituted oxy group (for example, a C1-4 alkoxy group), a carboxy group, and a substituted oxycarbonyl group (for example, a C1-4 alkoxycarbonyl group). These may be present singly or in combination of two or more.

[0030] Examples of the divalent hydrocarbon group containing an aromatic hydrocarbon ring include a group obtained by removing two hydrogen atoms from the structural formula of one aromatic hydrocarbon ring (for example, an arylene group having 6 to 12 carbon atoms such as a phenylene group and a naphthylene group), a group obtained by removing two hydrogen atoms from a structural formula in which two or more aromatic hydrocarbon rings are bonded via a single bond or a linking group, and a group in which the above group is bonded to a divalent aliphatic hydrocarbon group.

[0031] Examples of the linking group include a divalent aliphatic hydrocarbon group, a carbonyl group (—CO—), an ether bond (—O—), a thioether bond (—S—), and an ester bond (—COO—).

[0032] As the divalent aliphatic hydrocarbon group, for example, there may be mentioned linear or branched alkylene groups having 1 to 5 carbon atoms such as methylene group, methylmethylene group, dimethylmethylene group, ethylene group, propylene group, and trimethylene group.

[0033] R is preferably an arylene group having 6 to 12 carbon atoms, more preferably a phenylene group.

[0034] From the viewpoint of obtaining a semi-aromatic polyamide film excellent in dimensional stability in a high-temperature atmosphere, heat and humidity resistance in a high-temperature and high-humidity atmosphere, transparency, and achromaticity, n is preferably 6 to 12. n is more preferably 7 or more, still more preferably 8 or more, even more preferably 9 or more, and also more preferably 11 or less, still more preferably 10 or less. Specifically, n is more preferably 7 to 11, still more preferably 8 to 11, even more preferably 8 to 10, particularly preferably 9 or 10, and most preferably 9.

[0035] When n is an integer of 2 or more, the divalent saturated aliphatic hydrocarbon group represented by "C n H2 n " may be linear or branched.

[0036] As the semi-aromatic polyamide, a compound having a repeating unit represented by the following formula (pa-2) is particularly preferable. n in the following formula (pa-2) is the same as described above.

[0037] The semi-aromatic polyamide may have a repeating unit obtained by ring-opening polymerization of lactams such as ε-caprolactam, ζ-enanthlactam, η-capryllactam, and ω-laurolactam as long as the effects of the present invention are not impaired. That is, the semi-aromatic polyamide may have a repeating unit derived from lactams in addition to the repeating unit derived from the dicarboxylic acid component and the repeating unit derived from the diamine component.

[0038] The sum of the proportion of repeating units derived from the dicarboxylic acid component and the proportion of repeating units derived from the diamine component in all constituent units of the semi-aromatic polyamide (preferably the proportion of repeating units represented by the above formula (pa-1), more preferably the proportion of repeating units represented by the above formula (pa-2)) is preferably 60 mol% or more, more preferably 75 mol% or more, and even more preferably 90 mol% or more, from the viewpoint of obtaining a semi-aromatic polyamide film that is excellent in dimensional stability under high temperature atmospheres, heat resistance under high temperature and high humidity atmospheres, transparency, and achromaticity.

[0039] From the viewpoint of improving the dimensional stability of the semi-aromatic polyamide film in a high-temperature atmosphere and its heat resistance to moisture in a high-temperature, high-humidity atmosphere, as well as improving processability, the semi-aromatic polyamide preferably has a melting point (Tm) of 270 to 350°C, more preferably 300 to 330°C, and a glass transition temperature (Tg) of 120 to 180°C. By having Tm and Tg within the above ranges, the dimensional stability of the semi-aromatic polyamide film in a high-temperature atmosphere and its heat resistance to moisture in a high-temperature, high-humidity atmosphere are improved, and thermal decomposition during processing into a film can be effectively suppressed. The Tm and Tg of the semi-aromatic polyamide can be adjusted by the type of monomer constituting the semi-aromatic polyamide and the copolymerization ratio.

[0040] As the semi-aromatic polyamide, it is preferable to use at least one selected from the group consisting of polyamide 6T (reaction product of 1,6-hexanediamine and TPA), polyamide 9T (reaction product of NDA and / or MODA and TPA), polyamide 10T (reaction product of DDA and TPA), and polyamide 9N (reaction product of NDA and / or MODA and naphthalenedicarboxylic acid), and more preferably polyamide 9T.

[0041] The intrinsic viscosity of the semi-aromatic polyamide is preferably 0.8 to 2.0 dL / g, more preferably 0.9 to 1.8 dL / g, from the viewpoint of facilitating the production of films with excellent mechanical strength. The intrinsic viscosity of the semi-aromatic polyamide can be controlled by adjusting the degree of polymerization. The method for measuring the intrinsic viscosity of the semi-aromatic polyamide is described in the examples.

[0042] The semi-aromatic polyamide may contain a polymerization catalyst and an end-capturing agent. Examples of polymerization catalysts include phosphoric acid, phosphorous acid, hypophosphorous acid, or salts thereof. Examples of end-capturing agents include acetic acid, lauric acid, benzoic acid, octylamine, cyclohexylamine, and aniline.

[0043] Semi-aromatic polyamides can be produced using methods known for producing crystalline polyamides. Examples include solution polymerization or interfacial polymerization using acid chloride and a diamine component as raw materials (Method A), obtaining a low polymer using a dicarboxylic acid component and a diamine component as raw materials, and then increasing the molecular weight of the obtained low polymer by melt polymerization or solid-phase polymerization (Method B), obtaining a salt and a crushed mixture of the low polymer using a dicarboxylic acid component and a diamine component as raw materials, and then solid-phase polymerization of the obtained crushed mixture (Method C), and obtaining a salt using a dicarboxylic acid component and a diamine component as raw materials, and then solid-phase polymerization of the obtained salt (Method D).

[0044] Of the above methods, methods C and D are preferred, and method D is more preferred. Compared to method B, methods C and D allow for obtaining crushed mixtures and salts to be subjected to solid-phase polymerization at lower temperatures, and moreover, do not require large amounts of water when obtaining the crushed mixtures and salts to be subjected to solid-phase polymerization. Therefore, the generation of gel-like substances can be suppressed, and thereby the generation of fish eyes can be suppressed.

[0045] In method B, for example, a nylon salt prepared by mixing a diamine component, a dicarboxylic acid component, and a polymerization catalyst together can be heated and polymerized at 200 to 250°C to obtain a low polymer. The intrinsic viscosity of the low polymer is preferably 0.1 to 0.6 dL / g. Setting the intrinsic viscosity of the low polymer within this range has the advantage of preventing disruption of the molar balance between carboxyl groups in the dicarboxylic acid component and amino groups in the diamine component during subsequent melt polymerization or solid-phase polymerization, thereby increasing the polymerization rate. If the intrinsic viscosity of the low polymer is less than 0.1 dL / g, the polymerization time will be longer, which may result in lower productivity. On the other hand, if the intrinsic viscosity of the low polymer exceeds 0.6 dL / g, the resulting semi-aromatic polyamide may be discolored.

[0046] Solid-phase polymerization of low polymers is preferably carried out under reduced pressure or under an inert gas flow. Furthermore, the solid-phase polymerization temperature is preferably 200 to 280°C. By setting the solid-phase polymerization temperature within this range, discoloration and gelation of the resulting semi-aromatic polyamide can be suppressed. If the solid-phase polymerization temperature is below 200°C, the polymerization time will be longer, which may result in lower productivity. On the other hand, if the solid-phase polymerization temperature exceeds 280°C, the resulting semi-aromatic polyamide may discolor or gel.

[0047] It is preferable to carry out the melt polymerization of low polymers at a temperature of 350°C or lower. If the polymerization temperature exceeds 350°C, decomposition and thermal degradation of the semi-aromatic polyamide may be accelerated. As a result, semi-aromatic polyamide films obtained from such semi-aromatic polyamides may have inferior strength and appearance. The aforementioned melt polymerization also includes melt polymerization using a melt extruder.

[0048] In method C, for example, a suspension containing a molten aliphatic diamine component and a solid aromatic dicarboxylic acid component is stirred and mixed to obtain a mixture. Then, in this mixture, at a temperature below the melting point of the final semi-aromatic polyamide, a reaction to produce a salt by the reaction of the aromatic dicarboxylic acid component and the aliphatic diamine component, and a reaction to produce a low polymer by polymerization of the produced salt are carried out to obtain a mixture of salt and low polymer. In this case, crushing may be carried out while the reaction is in progress, or crushing may be carried out after the reaction has been completed and the mixture has been removed. The resulting reaction product is then subjected to solid-phase polymerization at a temperature below the melting point of the final semi-aromatic polyamide to increase its molecular weight to a predetermined molecular weight to obtain a semi-aromatic polyamide. Solid-phase polymerization is preferably carried out in an inert gas stream such as nitrogen at a polymerization temperature of 180 to 270°C and a reaction time of 0.5 to 10 hours.

[0049] In method D, for example, a powder of an aromatic dicarboxylic acid component is heated in advance to a temperature above the melting point of the aliphatic diamine component and below the melting point of the aromatic dicarboxylic acid. An aliphatic diamine component is then added to the aromatic dicarboxylic acid component powder at this temperature, without substantially containing water, in order to maintain the powder state, to obtain a salt. The obtained salt is then subjected to solid-phase polymerization at a temperature below the melting point of the final semi-aromatic polyamide to increase its molecular weight to a predetermined molecular weight to obtain a semi-aromatic polyamide. Solid-phase polymerization is preferably carried out in an inert gas stream such as nitrogen at a polymerization temperature of 180 to 270°C for a reaction time of 0.5 to 10 hours.

[0050] Commercially available semi-aromatic polyamides may be used. Examples of commercially available semi-aromatic polyamides include "Genesta®" from Kuraray, "Zecot®" from Unitika, "Lenny®" from Mitsubishi Engineering Plastics, "Arlen®" from Mitsui Chemicals, and "Ultramid®" from BASF.

[0051] The semi-aromatic polyamide composition may contain other resins besides semi-aromatic polyamide as resin components. However, from the viewpoint of obtaining a semi-aromatic polyamide film that is excellent in dimensional stability under high temperature atmospheres, heat and humidity resistance under high temperature and high humidity atmospheres, transparency, and achromaticity, the content of semi-aromatic polyamide is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 99% by mass or more, based on the total amount of resin components (100% by mass) contained in the semi-aromatic polyamide composition.

[0052] <Hindered phenol-based heat stabilizers and hindered amine-based heat stabilizers> By incorporating hindered phenol-based heat stabilizers and hindered amine-based heat stabilizers into the semi-aromatic polyamide composition, the formation of gel-like material during melt extrusion can be effectively suppressed. This not only allows for the production of high-quality semi-aromatic polyamide films with fewer foreign substances, but also reduces clogging of filters when removing gel-like material, enabling continuous and stable film production over long periods. Furthermore, it can suppress the decrease in tensile elongation of the semi-aromatic polyamide film after heat treatment.

[0053] The hindered phenol-based heat stabilizer can be any known compound without particular limitation, but from the viewpoint of suppressing decomposition during melt extrusion, it is preferably a compound whose mass decreases by 10% at a temperature of 330°C or higher, and more preferably, from the viewpoint of further improving the effects of the present invention, it is at least one selected from the group consisting of 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane and N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propanamide.

[0054] Examples of commercially available hindered phenol-based heat stabilizers include Irganox 1098 (manufactured by BASF), Rianox 1098 (manufactured by Rianlon), and Smirizer GA-80 (manufactured by Sumitomo Chemical).

[0055] While known hindered amine-based heat stabilizers can be used without particular limitations, from the viewpoint of suppressing decomposition during melt extrusion, it is preferable that the temperature at which the mass decreases by 10% is 330°C or higher. Furthermore, from the viewpoint of further improving the effects of the present invention, it is more preferable that it be at least one selected from the group consisting of N,N'-bis-2,2,6,6-tetramethyl-4-piperidinyl-1,3-benzenedicaramide and 2-ethyl-2'-ethoxyoxalanilide.

[0056] Examples of commercially available hindered amine-based heat stabilizers include NYLOSTAB S-EED FF (manufactured by CLARIANT).

[0057] In the semi-aromatic polyamide composition of the present invention, the content ratio of the hindered phenol-based heat stabilizer to the hindered amine-based heat stabilizer is not particularly limited. However, from the viewpoint of further improving the effects of the present invention, the content of the hindered phenol-based heat stabilizer is preferably 0.5 to 10 parts by mass, more preferably 1 to 9 parts by mass, even more preferably 1 to 8 parts by mass, even more preferably 1 to 6 parts by mass, and particularly preferably 1 to 4 parts by mass, per 1 part by mass of the hindered amine-based heat stabilizer.

[0058] In the semi-aromatic polyamide composition of the present invention, the content of the hindered phenol-based heat stabilizer is not particularly limited. However, from the viewpoint of further improving the effects of the present invention, suppressing bleed-out to the film surface, and suppressing poor feeding during melt extrusion (a phenomenon in which raw material chips have difficulty entering the extruder and the amount of extrusion decreases), which reduces the amount of discharged molten semi-aromatic polyamide composition and lowers the production efficiency of the film, the content is preferably 0.1 to 1.5% by mass, more preferably 0.2 to 1.4% by mass, even more preferably 0.3 to 1.3% by mass, even more preferably 0.4 to 1.2% by mass, and particularly preferably 0.4 to 1.0% by mass.

[0059] <Other Additives> The semi-aromatic polyamide composition of the present invention contains at least a semi-aromatic polyamide, a hindered phenol-based heat stabilizer, and a hindered amine-based heat stabilizer. However, other additives may be included as needed to improve the properties of the film without impairing the effects of the present invention. Examples of other additives include lubricants, colorants (e.g., pigments such as titanium dioxide, dyes, etc.), color inhibitors, heat stabilizers (except hindered phenol-based heat stabilizers and hindered amine-based heat stabilizers), antioxidants (e.g., phosphate esters, phosphite esters, etc.), weather resistance improvers (e.g., benzotriazole compounds, etc.), flame retardants (e.g., halogen-based flame retardants, phosphorus-based flame retardants, etc.), plasticizers, mold release agents, reinforcing agents (e.g., talc, etc.), modifiers, antistatic agents, ultraviolet absorbers, antifogging agents, and various polymers. These may be included individually or in combination of two or more.

[0060] Lubricants are components that reduce friction and improve slipperiness. Examples include inorganic particles such as silica, alumina, titanium dioxide, calcium carbonate, kaolin, and barium sulfate; and organic particles such as acrylic resin particles, melamine resin particles, silicone resin particles, and cross-linked polystyrene particles. These can be included individually or in combination of two or more.

[0061] The average particle size (median diameter by volume) of the lubricant is, for example, 0.05 to 5.0 μm. The average particle size is preferably 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 1.0 μm or more, particularly preferably 2.0 μm or more, and also preferably 4.5 μm or less, more preferably 4.0 μm or less, even more preferably 3.5 μm or less, particularly preferably 3.0 μm or less. Specifically, the average particle size of the lubricant is preferably 0.1 to 4.5 μm, more preferably 0.5 to 4.0 μm, even more preferably 1.0 to 3.5 μm, particularly preferably 2.0 to 3.0 μm. The lubricant content is, for example, 0.3 parts by mass or less, preferably 0.05 to 0.3 parts by mass, per 100 parts by mass of semi-aromatic polyamide. The average particle size and content of the lubricant are adjusted as appropriate according to the required properties for the semi-aromatic polyamide film, such as friction properties and optical properties.

[0062] <Thickening properties of semi-aromatic polyamide compositions> It is preferable that the viscosity of a semi-aromatic polyamide composition does not increase during the melting time. The gel-like substance produced during melt extrusion is formed when the molecular chains of the resin are bonded together by some chemical bond during melt extrusion, forming a three-dimensional network structure, losing fluidity, and becoming solid. During the formation of the gel-like substance, the melt viscosity of the semi-aromatic polyamide composition increases. In other words, the increase in melt viscosity that occurs when a semi-aromatic polyamide composition is subjected to a thermal history serves as an indicator of gelation.

[0063] <Productivity of Semi-Aromatic Polyamide Films> From an economic standpoint, it is preferable to have a high production volume per run. The more foreign matter that is captured by the extrusion filter in continuous melt extrusion, the higher the filter pressure becomes, making it difficult to continue production for long periods due to filter clogging. In addition, in order to reduce the number of defects caused by foreign matter in the film, it is preferable to use a finer filter, but it is undesirable if the rate of pressure increase of the filter becomes too high, limiting the production time. Also, a low extrusion rate (discharge rate) per hour is undesirable because it reduces production.

[0064] The semi-aromatic polyamide composition of the present invention, by containing a combination of a hindered phenol-based heat stabilizer and a hindered amine-based heat stabilizer, can effectively suppress the unexpected formation of gel-like material during melt extrusion, thereby effectively suppressing the increase in melt viscosity. Furthermore, because the semi-aromatic polyamide composition of the present invention can effectively suppress the formation of gel-like material during melt extrusion, it can suppress filter clogging and improve the productivity of semi-aromatic polyamide films.

[0065] <Preparation of Semi-Aromatic Polyamide Composition> The method for preparing the semi-aromatic polyamide composition of the present invention is not particularly limited. Before putting the semi-aromatic polyamide into the extruder, the semi-aromatic polyamide composition may be prepared in advance by mixing at least the semi-aromatic polyamide with a hindered phenol-based heat stabilizer and a hindered amine-based heat stabilizer. Alternatively, the semi-aromatic polyamide composition may be prepared by putting each component into the extruder during film formation and mixing (melt kneading) them. The order in which the components are mixed and the order in which the components are put into the extruder are not particularly limited. Furthermore, in preparing the semi-aromatic polyamide composition of the present invention, pellets (masterbatch) containing at least the semi-aromatic polyamide and various additives may be used.

[0066] Typical methods for preparing semi-aromatic polyamide compositions include the following: (1) A method of mixing at least semi-aromatic polyamide, a hindered phenol-based heat stabilizer, and a hindered amine-based heat stabilizer. (2) A method of preparing pellets (masterbatch) by melt-kneading a high concentration of additives (e.g., lubricants) with semi-aromatic polyamide, and then melt-kneading the masterbatch, natural pellets (additive-free semi-aromatic polyamide pellets), a hindered phenol-based heat stabilizer, and a hindered amine-based heat stabilizer in an extruder during film formation (masterbatch method). (3) A method of loading a dry blend containing at least semi-aromatic polyamide, a hindered phenol-based heat stabilizer, and a hindered amine-based heat stabilizer into an extruder and melt-kneading it in the extruder. (4) A method of loading at least semi-aromatic polyamide, a hindered phenol-based heat stabilizer, and a hindered amine-based heat stabilizer into an extruder separately and melt-kneading them in the extruder.

[0067] 2. Semi-aromatic polyamide film The semi-aromatic polyamide film of the present invention is obtained from the semi-aromatic polyamide composition.

[0068] <Heat Shrinkage Ratio> The heat shrinkage ratio S in the longitudinal direction of the semi-aromatic polyamide film of the present invention is determined by heat treatment at a temperature of 250°C for 5 minutes, followed by leaving it at a temperature of 23°C and a humidity of 50% RH for 2 hours, in order to improve dimensional stability in a high-temperature atmosphere. MD and thermal shrinkage coefficient S in the width direction TD However, each is preferably -1.0 to 1.5%, more preferably -0.8 to 1.3%, even more preferably -0.6 to 1.0%, even more preferably -0.4 to 0.6%, and particularly preferably -0.2 to 0.4%. Longitudinal heat shrinkage S of the semi-aromatic polyamide film of the present invention MD and thermal shrinkage coefficient S in the width direction TD The range can be adjusted by the type of semi-aromatic polyamide, the respective contents of hindered phenol-based heat stabilizers and hindered amine-based heat stabilizers, the stretching conditions, the heat-fixing treatment conditions, and the relaxation treatment conditions.

[0069] In the present invention, the thermal shrinkage rate of the semi-aromatic polyamide film is measured by the method described in the examples.

[0070] <Retention Rate of Tensile Elongation at Break> From the viewpoint of improving moisture heat resistance in a high-temperature, high-humidity atmosphere, the semi-aromatic polyamide film of the present invention has a retention rate of tensile elongation at break in the longitudinal and width directions of the film after moist heat treatment at a temperature of 121°C and a humidity of 100% RH for 120 hours, preferably 80% or more, more preferably 85% or more, even more preferably 90% or more, and even more preferably 95% or more, respectively. The retention rate of tensile elongation at break in the longitudinal and width directions of the semi-aromatic polyamide film of the present invention can be adjusted to the above range depending on the type of semi-aromatic polyamide, the respective contents of hindered phenol-based heat stabilizers and hindered amine-based heat stabilizers, stretching conditions, heat setting treatment conditions, and relaxation treatment conditions.

[0071] In the present invention, the retention rate of the tensile break elongation of the semi-aromatic polyamide film is measured by the method described in the examples.

[0072] <Yellowness (YI)> From the viewpoint of improving visibility, the semi-aromatic polyamide film of the present invention preferably has a yellowness (YI) of 10 or less in absolute value, more preferably 8 or less in absolute value, even more preferably 6 or less in absolute value, even more preferably 4 or less in absolute value, and particularly preferably 2 or less in absolute value. The yellowness (YI) of the semi-aromatic polyamide film of the present invention can be adjusted to the above range depending on the type of semi-aromatic polyamide, the conditions of the heat-setting treatment of the stretched film, and the film thickness, etc.

[0073] In the present invention, the yellowness (YI) of the semi-aromatic polyamide film is measured by the method described in the examples.

[0074] <Tensile Breaking Strength> From the viewpoint of providing high break resistance, the semi-aromatic polyamide film of the present invention has a tensile breaking strength in the longitudinal direction and width direction of the film, preferably 150 MPa or more, more preferably 155 MPa or more, even more preferably 160 MPa or more, and even more preferably 165 MPa or more. The tensile breaking strength in the longitudinal direction and width direction of the semi-aromatic polyamide film of the present invention can be adjusted to the above range by the type of semi-aromatic polyamide, the respective contents of the hindered phenol-based heat stabilizer and the hindered amine-based heat stabilizer, the stretching conditions, the heat setting treatment conditions, and the relaxation treatment conditions.

[0075] In the present invention, the tensile breaking strength of the semi-aromatic polyamide film is measured by the method described in the examples.

[0076] <Thickness> The thickness of the semi-aromatic polyamide film of the present invention is adjusted as appropriate depending on the application and purpose, but from the viewpoint of film strength, transparency and achromaticity, it is preferably 1 to 150 μm, more preferably 10 to 100 μm, even more preferably 20 to 80 μm, and even more preferably 30 to 60 μm.

[0077] <Applications> The semi-aromatic polyamide film of the present invention has high transparency and achromaticity, excellent dimensional stability in high-temperature atmospheres, and high heat and humidity resistance in high-temperature and high-humidity atmospheres, making it suitable for use in various electronic materials, optical components, electrical insulating materials, automotive materials, and building materials. Specifically, the semi-aromatic polyamide film of the present invention can be used as an LED mounting substrate, an optical substrate for various displays such as liquid crystal and organic EL, a substrate for flexible printed wiring, a coverlay film for flexible printed wiring, a heat-resistant masking tape, an industrial process tape such as a heat-resistant tape for semiconductor manufacturing processes, a substrate material for solar cell modules, an automotive sensor material, and a film used in automotive protective materials.

[0078] 3. Method for producing a semi-aromatic polyamide film The semi-aromatic polyamide film of the present invention can be produced, for example, by forming an unstretched film (film formation) by extruding the semi-aromatic polyamide composition, and then stretching the unstretched film.

[0079] The raw materials for the semi-aromatic polyamide film may be a mixture of virgin raw materials, or they may be a mixture of off-spec films or scraps generated as edge trim during the production of the semi-aromatic polyamide film, or a mixture of virgin raw materials prepared by adding virgin raw materials to the scrap mixture.

[0080] <Film Formation> The film formation process involves melting and extruding the semi-aromatic polyamide composition in an extruder, discharging the molten material in a sheet-like form from a flat die such as a T-die or I-die, and cooling it by bringing it into contact with the cooling surface of a moving cooler such as a cooling roll or steel belt to form an unstretched film.

[0081] The semi-aromatic polyamide composition is melted and mixed in an extruder for about 5 to 10 minutes at, for example, a temperature of about 280 to 340°C. The extrusion temperature is preferably between the melting point (Tm) of the semi-aromatic polyamide and 330°C, from the viewpoint of facilitating extrusion and suppressing the decomposition of the semi-aromatic polyamide.

[0082] From the viewpoint of suppressing the crystallization of the semi-aromatic polyamide and obtaining an unstretched film that is easy to stretch and can be stretched to a uniform thickness, the temperature of the cooling surface of the moving cooler is preferably 30 to 60°C, more preferably 30 to 50°C, and even more preferably 30 to 40°C.

[0083] The thickness of the unstretched film needs to be adjusted appropriately depending on the desired thickness of the semi-aromatic polyamide film and the stretching ratio, but it is typically around 100 to 800 μm.

[0084] The heat of crystallization of the unstretched film is preferably 20 J / g or more, more preferably 25 J / g or more, from the viewpoint of improving the tensile elongation at break, reducing haze, and stabilizing the stretching process. If the heat of crystallization of the unstretched film is less than 20 J / g, crystallization is progressing, and the film obtained by stretching this unstretched film tends to have a low tensile elongation at break, or high haze if it contains a lubricant such as silica. In addition, stretching becomes unstable, and stretching may become impossible due to frequent breakage. Furthermore, a higher stretching force is required in the initial stages of stretching, making it difficult to obtain a stretched film of uniform thickness. The method for measuring the heat of crystallization of the unstretched film is as described in the examples.

[0085] <Stretching> The stretching step is a step in which the unstretched film obtained in the film formation step is stretched to obtain a stretched film. When the unstretched film is stretched, the semi-aromatic polyamide contained in the unstretched film becomes oriented and crystallizes. The stretching may be uniaxial stretching or biaxial stretching, but biaxial stretching is preferred.

[0086] The biaxial stretching method is not particularly limited and examples include the flat sequential biaxial stretching method, the flat simultaneous biaxial stretching method, and the tubular method.

[0087] The stretching ratio is preferably 2.0 to 3.5 times in the longitudinal direction and 2.0 to 4.0 times in the width direction, and more preferably 2.0 to 3.0 times in the longitudinal direction and 2.8 to 4.0 times in the width direction.

[0088] In the case of sequential biaxial stretching, the stretching ratio is more preferably 2.3 to 2.6 times in the longitudinal direction and 3.3 to 3.8 times in the width direction. In the case of sequential biaxial stretching, if the stretching ratio in the longitudinal direction exceeds 3.5 times, the resulting stretched film may undergo excessive crystallization, resulting in a decrease in stretchability in the width direction. Furthermore, even if stretching in the width direction is achieved, the resulting stretched film is prone to stretching unevenness, which can lead to a decrease in thickness accuracy, a decrease in tensile elongation at break in the longitudinal direction, and a decrease in transparency.

[0089] In the case of simultaneous biaxial stretching, the stretching ratio is more preferably 2.5 to 3.3 times in the longitudinal direction and 2.5 to 3.5 times in the width direction, and even more preferably 2.8 to 3.2 times in the longitudinal direction and 2.8 to 3.3 times in the width direction. In the case of simultaneous biaxial stretching, if the stretching ratio in the longitudinal direction exceeds 3.5 times, the resulting stretched film may have a high thermal shrinkage rate and reduced dimensional stability. On the other hand, if the stretching ratio in the width direction exceeds 4.0 times, the thermal shrinkage rate increases, dimensional stability decreases, and the tensile elongation at break may further decrease.

[0090] When the stretching ratio in the longitudinal and width directions is less than 2.0 times, the resulting stretched film is prone to stretching unevenness, which can result in uneven thickness and reduced flatness.

[0091] The stretching speed is preferably such that the stretching strain rate in both the longitudinal and width directions exceeds 400% / min, more preferably between 800 and 12000% / min, and even more preferably between 1200 and 6000% / min. If the stretching strain rate is 400% / min or less, crystals may grow during stretching, causing the film to break. If the stretching strain rate is too high, the unstretched sheet may not be able to follow the deformation and may break.

[0092] From the viewpoint of preventing film breakage and obtaining a stably stretched film, and from the viewpoint of suppressing the occurrence of stretching unevenness in the film, the stretching temperature is preferably a temperature above the glass transition temperature (Tg) of the semi-aromatic polyamide, more preferably a temperature above Tg and below (Tg + 35°C), and even more preferably a temperature above Tg and below (Tg + 15°C).

[0093] <Heat Fixing Treatment> The method for producing the semi-aromatic polyamide film of the present invention preferably includes a heat fixing treatment step. The heat fixing treatment step is a step in which the stretched film is subjected to heat treatment while being held by the clips used during stretching. By subjecting the stretched film to heat fixing treatment, the occurrence of heat damage unevenness is suppressed, and the heat shrinkage rate of the semi-aromatic polyamide film can be further reduced.

[0094] The heat-setting temperature is preferably the melting point (Tm) of the semi-aromatic polyamide minus (10 to 22°C), and more preferably the melting point (Tm) of the semi-aromatic polyamide minus (10 to 20°C), from the viewpoint of suppressing thermal shrinkage in a high-temperature atmosphere, improving tensile elongation at break, reducing yellowness, suppressing appearance defects due to heat-induced wrinkles, and preventing breakage. The heat-setting treatment may be carried out by maintaining a constant temperature or by providing a temperature gradient.

[0095] The heat setting time needs to be adjusted appropriately depending on the thickness of the stretched film, but from the viewpoint of further reducing the heat shrinkage rate of the semi-aromatic polyamide film, it is, for example, 1 to 50 seconds, preferably 3 to 40 seconds, and more preferably 5 to 35 seconds.

[0096] The heat setting process can be carried out by known methods such as blowing hot air, irradiating with infrared rays, or irradiating with microwaves. From the viewpoint of uniform and precise heating, the method of blowing hot air is preferred.

[0097] <Relaxation Treatment> The method for producing a semi-aromatic polyamide film of the present invention preferably includes a relaxation treatment step. The relaxation treatment step is a step of relaxing a stretched film at a predetermined relaxation rate under predetermined temperature conditions. By relaxing the stretched film, residual stress in the stretched film can be removed and its thermal dimensional stability can be improved.

[0098] The relaxation process can be performed in-line, simultaneously or separately, in the longitudinal and width directions. When performed separately, methods include relaxing the longitudinal direction first, then the width direction, or relaxing the width direction first, then the longitudinal direction. In the case of sequential biaxial stretching, the relaxation process can be (i) performed simultaneously in-line in the longitudinal and width directions after longitudinal stretching and transverse stretching, followed by heat fixing, or (ii) performed longitudinal stretching, then relaxation in the longitudinal direction, followed by transverse stretching, heat fixing, and then relaxation in the width direction. Note that in (ii), if heat fixing is performed after longitudinal stretching and longitudinal relaxation, the resulting film becomes difficult to stretch transversely, so it is not preferable to perform heat fixing before transverse stretching. Furthermore, in the sequential biaxial stretching methods described in (i) and (ii) above, the material is stretched longitudinally first, followed by transverse stretching. However, in the sequential biaxial stretching method, it is also acceptable to stretch the material transversely first, followed by longitudinal stretching. Additionally, the relaxation process can be performed in-line in the width direction after biaxial stretching, and then, after being wound up, the material can be relaxed in the longitudinal direction by passing it through a drying oven set to a predetermined temperature under low tension offline.

[0099] The relaxation temperature is not particularly limited, but it is preferable that it be the same temperature as the temperature during the heat fixation process (the same temperature as the heat fixation temperature if the heat fixation process is performed at a constant temperature, or the final heat fixation temperature in the heat fixation process if the heat fixation process is performed with a temperature gradient).

[0100] The relaxation time needs to be adjusted as appropriate depending on the thickness of the stretched film, but for example, it is 5 to 30 seconds, preferably 5 to 15 seconds.

[0101] The longitudinal relaxation rate needs to be adjusted appropriately depending on the thickness of the stretched film, but from the viewpoint of further reducing the longitudinal heat shrinkage rate of the semi-aromatic polyamide film and preventing film sagging, it is preferably 1.0 to 6.0%, more preferably 1.5 to 5.0%, and even more preferably 2.0 to 4.0%.

[0102] The degree of relaxation in the width direction needs to be adjusted appropriately depending on the thickness of the stretched film, but from the viewpoint of further reducing the thermal shrinkage rate in the width direction of the semi-aromatic polyamide film and preventing sagging of the film, it is preferably 1.0 to 5.0%, more preferably 1.5 to 4.0%, and even more preferably 1.5 to 3.0%.

[0103] Because semi-aromatic polyamides are highly crystalline, applying sequential biaxial stretching can easily cause oriented crystallization in the unstretched film when stretched in the longitudinal or widthwise direction. Since oriented crystallized films can be difficult to stretch in the next orthogonal direction, it is preferable to apply simultaneous biaxial stretching. On the other hand, when the thickness of the unstretched film exceeds 50 μm, simultaneous biaxial stretching results in excessively high stretching forces, significantly increasing the difficulty of stretching. Therefore, for biaxial stretching of unstretched films with high stretching forces, it is preferable to apply sequential biaxial stretching rather than simultaneous biaxial stretching.

[0104] In the apparatus for producing the semi-aromatic polyamide film of the present invention, for example, the surfaces of the cylinder, barrel melting section, metering section, single pipe, filter, and T-die are preferably treated to reduce surface roughness in order to prevent the accumulation of raw materials. Methods for reducing surface roughness include, for example, surface modification with a low-polarity substance, or deposition of silicon nitride or diamond-like carbon on the surface.

[0105] The semi-aromatic polyamide film produced by the above method may be in the form of a single sheet or in the form of a film roll when wound onto a winding roll, but from the viewpoint of productivity when used for various applications, it is preferable to be in the form of a film roll. The film in the form of a film roll may be slit to a desired width.

[0106] The semi-aromatic polyamide film of the present invention may be a single-layer film composed of one type of layer or a multilayer structure formed by laminating two or more types of layers. When adopting a multilayer structure, for example, in the case of a two-layer film, a lubricant can be contained in any one of the two layers, and in the case of a three-layer film, lubricants can be respectively contained in the layers located on both surfaces among the three layers. The type and content of the lubricant to be contained can be designed independently. By adopting such a multilayer structure, the surface roughness of each surface of the film can be independently controlled.

[0107] In order to improve the adhesiveness with other materials, the surface of the semi-aromatic polyamide film of the present invention may be subjected to surface treatments such as corona treatment, plasma treatment, acid treatment, and flame treatment.

[0108] Layers formed of inorganic substances such as metals or their oxides, other types of polymers, paper, woven fabrics, non-woven fabrics, and wood may be laminated on the semi-aromatic polyamide film of the present invention.

[0109] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[0110] 1. Evaluation method (1) Using an Ubbelohde viscometer for the intrinsic viscosity of semi-aromatic polyamide, in concentrated sulfuric acid at 30 °C, the intrinsic viscosity (η inh ) of semi-aromatic polyamide under each concentration of 0.05 g / dL, 0.1 g / dL, 0.2 g / dL, and 0.4 g / dL was calculated from the following formula, and the obtained intrinsic viscosity (η inh ) was extrapolated so that the concentration of semi-aromatic polyamide became zero, and the value was taken as the limiting viscosity [η]. η inh = [ln(t1 / t0)] / c [In the formula, η inh is the intrinsic viscosity (dL / g), t0 is the flow-down time of the solvent (seconds), t1 is the flow-down time of the semi-aromatic polyamide solution (seconds), and c is the concentration of semi-aromatic polyamide in the semi-aromatic polyamide solution (g / dL).]

[0111] (2) Melting point and glass transition temperature of semi-aromatic polyamide Using a differential scanning calorimeter (PerkinElmer, DSC-7), semi-aromatic polyamide was heated from 20°C to 350°C at a rate of 10°C / min under a nitrogen atmosphere and held for 5 minutes (1st Scan), then cooled from 350°C to 20°C at a rate of 100°C / min and held for 5 minutes. The glass transition temperature observed during the process of further heating from 20°C to 350°C at a rate of 10°C / min (2nd Scan) was defined as the glass transition temperature Tg of the semi-aromatic polyamide. Similarly, the peak top temperature of the crystal melting peak observed in the 2nd Scan was defined as the melting point Tm.

[0112] (3) Thickening properties of semi-aromatic polyamide compositions Dynamic viscoelasticity measurements of semi-aromatic polyamide compositions were performed using an ARESG2 rheometer manufactured by TA Instruments under the following conditions: Measurement temperature: 320°C Strain: 5% Frequency: 0.1 to 100 rad / s Fixture: 25 mm parallel plate (gap distance 1.5 mm) Measurement atmosphere: under nitrogen environment Repeated measurements: 15 times From the obtained viscosity data, the viscosity η of the first measurement at 1 rad / s was calculated 1 This process is repeated until the viscosity η at 1 rad / s is measured for the 15th time. 15 The viscosity ratio was determined using the following formula: Viscosity ratio = η 15 / η 1 The viscosity of the semi-aromatic polyamide compositions was then evaluated according to the following criteria: [Evaluation Criteria] A: Viscosity ratio less than 9 B: Viscosity ratio 9 or more and less than 11 C: Viscosity ratio 11 or more and less than 13 D: Viscosity ratio 13 or more

[0113] (4) The pressurized semi-aromatic polyamide composition for the filter was introduced into a single-screw extruder heated to a cylinder temperature of 320°C and melted. The mixture was then filtered through a flat plate filter (NF-10D, manufactured by Nippon Seisen Co., Ltd., nominal filtration diameter 30 μm) having a breaker plate on the back, and subsequently extruded from a T-die heated to 320°C. During extrusion, the flow rate per unit area of ​​the filter was 0.8 kg / cm³. 2The extrusion rate was set to be equal to MPa / hour, and the time at which the set extrusion rate was reached was defined as the extrusion start time. The upstream pressure of the filter at the start of extrusion and the upstream pressure of the filter 10 hours after the start of extrusion were recorded, and the filter pressure increase rate was calculated using the following formula: Filter pressure increase rate (MPa / h) = (Upstream pressure of the filter 10 hours after the start of extrusion (MPa) - Upstream pressure of the filter at the start of extrusion (MPa)) / 10 (h) The pressure increase performance of the filter was then evaluated according to the following criteria: [Evaluation criteria] A: Filter pressure increase rate is less than 0.20 MPa / h B: Filter pressure increase rate is 0.20 or more and less than 0.25 MPa / h C: Filter pressure increase rate is 0.25 or more and less than 0.30 MPa / h D: Filter pressure increase rate is 0.30 MPa / h or more

[0114] (5) Discharge volume The semi-aromatic polyamide composition was fed into a single-screw extruder with a screw diameter of φ90 mm and a screw length (L) / screw diameter (D) = 29, with the cylinder temperature heated to 320°C. The extrusion screw rotation speed was set to 60 rpm and melt extrusion was performed, with the amount of extrusion per hour being defined as the discharge volume (kg / h).

[0115] (6) Heat shrinkage rate of semi-aromatic polyamide film A test specimen (longitudinal dimension 100 mm x width dimension 10 mm) was cut from the semi-aromatic polyamide film and left for 2 hours in an atmosphere of 23°C and 50% RH. After that, the longitudinal dimension (MD direction) of the test specimen was measured using an image dimension measuring instrument (Keyence Corporation, IM-7000). The test specimen was heat-treated in an atmosphere of 250°C for 5 minutes and then left for 2 hours in an atmosphere of 23°C and 50% RH. After that, the MD direction dimension of the test specimen was measured using the IM-7000. The heat shrinkage rate in the MD direction (S) was calculated using the following formula. MD The S of the three test specimens was calculated. MD The average value of the S of the semi-aromatic polyamide film MD S MD (%) = {(Dimensions in the MD direction before heat treatment - Dimensions in the MD direction after heat treatment) / Dimensions in the MD direction before heat treatment] × 100 Heat shrinkage rate (S) in the width direction (TD direction) of semi-aromatic polyamide film TD) Except for using a test specimen (width dimension 100 mm x length dimension 10 mm), the above S MD The measurement is performed using the same method, and the thermal shrinkage rate in the TD direction (S) is calculated using the following formula. TD The S of the three test specimens was calculated. TD The average value of the S of the semi-aromatic polyamide film TD S TD (%) = {(Dimension in the TD direction before heat treatment - Dimension in the TD direction after heat treatment) / Dimension in the TD direction before heat treatment] × 100

[0116] (7) Retention of tensile elongation at break of semi-aromatic polyamide film The tensile elongation at break in the longitudinal (length direction) and width direction of five semi-aromatic polyamide film test specimens (150 mm in length, 10 mm in width) was measured using an Autograph AG-X manufactured by Shimadzu Corporation at a test speed of 500 mm / min, in accordance with JIS K7127:1999 (Plastics - Test methods for tensile properties - Part 3: Test conditions for films and sheets), and the average value was calculated. In addition, five semi-aromatic polyamide film test specimens (150 mm in length, 10 mm in width) were subjected to moist heat treatment for 120 hours in an environment of 2 atm, temperature 121°C, and relative humidity 100%, and then left for 2 hours at a temperature of 23°C and humidity 50% RH. After that, the tensile elongation at break in the longitudinal (length direction) and width direction of the five test specimens was measured in the same manner as above, and the average value was calculated. The retention rate (%) of the tensile elongation at break in the longitudinal and width directions before and after moist heat treatment was calculated using the following formula: Retention rate of tensile elongation at break = (Average value of tensile elongation at break after moist heat treatment / Average value of tensile elongation at break before moist heat treatment) × 100

[0117] (8) Yellowness (YI E313) of semi-aromatic polyamide film A test specimen of semi-aromatic polyamide film (50 mm wide x 50 mm long) was used to measure the yellowness (YI E313) of the semi-aromatic polyamide film using a spectrophotometer / colorimeter SE 6000 manufactured by Nippon Denshoku Industries Co., Ltd., in accordance with JIS K 7373:2006 (Plastics - Method for determining yellowness and degree of yellowing), under geometric optical conditions e, 0° illumination, and 0° reception. The calculation method for yellowness was "using the standard illuminant D65 and the XYZ color system".

[0118] (9) Tensile breaking strength of semi-aromatic polyamide film The tensile breaking strength in the longitudinal and width directions of five semi-aromatic polyamide film test specimens (150 mm in length, 10 mm in width) was measured using an Autograph AG-X manufactured by Shimadzu Corporation at a test speed of 500 mm / min, in accordance with JIS K7127:1999 (Plastics - Test methods for tensile properties - Part 3: Test conditions for films and sheets), and the average value was calculated.

[0119] 2. Raw Materials (1) Semi-aromatic polyamide Semi-aromatic polyamide A obtained in the following Production Example 1 was used. Production Example 1 3289 parts by mass of terephthalic acid (TA), 2533 parts by mass of 1,9-nonanediamine (NDA), 633 parts by mass of 2-methyl-1,8-octanediamine (MODA), 48.9 parts by mass of benzoic acid (BA), 6.5 parts by mass of sodium hypophosphate monohydrate (corresponding to 0.1% by mass of the total of TA, NDA, MODA, and BA), and 2200 parts by mass of distilled water were placed in a reaction vessel and purged with nitrogen. The molar ratio of these raw materials (TA / BA / NDA / MODA) was 99 / 2 / 80 / 20. The contents of the reaction vessel were stirred at 100°C for 30 minutes, and then the internal temperature was raised to 210°C over 2 hours. At this time, the pressure inside the reaction vessel was 2.12 MPa (22 kg / cm²). 2 The pressure was increased to ). The reaction continued for 1 hour, then the temperature was raised to 230°C, and the temperature was maintained at 230°C for 2 hours, during which the water vapor was gradually released and the pressure was reduced to 2.12 MPa (22 kg / cm²). 2 The reaction was carried out while maintaining the pressure at 0.98 MPa (10 kg / cm²). Next, the pressure was increased to 0.98 MPa (10 kg / cm²) over 30 minutes. 2 The temperature was lowered to 30°C and the mixture was reacted for another hour to obtain a prepolymer. The obtained prepolymer was dried at 100°C under reduced pressure for 12 hours, and then pulverized to a size of 2 mm or less. Next, the pulverized prepolymer was solid-state polymerized at a temperature of 230°C and a pressure of 13.3 Pa (0.1 mmHg) for 10 hours to obtain a semi-aromatic polyamide (PA9T). The obtained PA9T was supplied to a twin-screw extruder (manufactured by Japan Steel Works, Ltd., TEX44C), melt-kneaded and extruded at a cylinder temperature of 320°C, cooled, and cut to produce pellets of semi-aromatic polyamide A. The melting point, glass transition temperature, and intrinsic viscosity of semi-aromatic polyamide A are shown in Table 1.

[0120]

[0121] (2) Silica-containing master tip A master tip (M1) containing 1% by mass of silica, obtained in the following Production Example 2, was used. Production Example 2 A master tip (M1) containing 1% by mass of silica was prepared by melt-kneading 99 parts by mass of semi-aromatic polyamide A and 1 part by mass of silica (manufactured by Fuji Silicia Chemical Co., Ltd., Silophobic 100, average particle size 2.7 μm).

[0122] (3) Heat stabilizer a: Hindered phenol type 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (manufactured by Sumitomo Chemical Co., Ltd., SumiLizer GA-80)

[0123] (4) Heat stabilizer b: Hindered amine type N,N'-bis-2,2,6,6-tetramethyl-4-piperidinyl-1,3-benzenedicarboxamide (manufactured by Clariant, NYLOSTAB S-EED FF)

[0124] (5) Heat stabilizer c: Phosphorus-based tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylenediphosphonite (Clariant, Hostanox P-EPQ)

[0125] Example 1 (Production of Semi-Aromatic Polyamide Film) (Film Formation) A mixture was obtained by mixing semi-aromatic polyamide A, heat stabilizer a, heat stabilizer b, and master tip (M1) in an amount of 0.6 parts by mass of heat stabilizer a, 0.2 parts by mass of heat stabilizer b, and 0.2 parts by mass of silica with 100 parts by mass of semi-aromatic polyamide A. The obtained mixture was put into a 90 mm single-screw extruder set to a cylinder temperature of 295°C (first stage), 320°C (middle stage), and 320°C (last stage) and melted. The mixture was filtered through a flat plate filter with a breaker plate on the back (NF-13D manufactured by Nippon Seisen Co., Ltd., nominal filtration diameter 60 μm), extruded into a sheet from a T-die set to 320°C, and cooled by electrostatic adhesion onto a cooling roll set to a surface temperature of 40°C to obtain a substantially unoriented, unstretched film with a thickness of 430 μm (crystallization heat: 27 J / g). The heat of crystallization of the unstretched film was measured by the following method. 10 mg of the unstretched film was heated from 40°C to 350°C at a rate of 20°C / min in a nitrogen atmosphere using a differential scanning calorimeter (PerkinElmer, DSC-7) (1st Scan), and the heat of the resulting exothermic peak was determined. The cooling roll used had a 0.15 mm thick ceramic (Al2O3) coating on its surface. Two carbon brushes were placed upstream of the point where the roll surface and the film made contact, and the carbon brush holders were grounded to remove static electricity from the surface of the ceramic coating layer. A 0.2 mm diameter tungsten wire was used as the electrode, and a voltage of 6.5 kV was applied using a 300 W (15 kV × 20 mA) DC high-voltage generator.

[0126] (Biaxial stretching) Next, the unstretched film was biaxially stretched using a flat-type sequential stretcher. First, the unstretched film was heated to 130°C by roll heating and infrared heating, and stretched in the longitudinal direction (longitudinal direction) at a stretching ratio of 2.5 times to obtain a longitudinally stretched film. Subsequently, the longitudinally stretched film was continuously guided to a transverse stretcher while both ends were held with clips, and sequential biaxial stretching was performed. Inside the transverse stretcher, the machine was preheated to 123°C, and the longitudinally stretched film was transversely stretched at a stretching section temperature of 130°C and a stretching ratio of 3.4 times to obtain a biaxially stretched film.

[0127] (Heat setting treatment) The biaxially oriented film, while still held by clips, was heat-set in a heat setting zone at 278°C for 29 seconds.

[0128] (Relaxation Treatment) Subsequently, under a temperature atmosphere of 278°C, the distance between clips was adjusted to perform a relaxation treatment for 10 seconds at a relaxation rate of 3.0% in the longitudinal direction and 1.9% in the transverse direction (width direction). The film was then cooled to 80°C to obtain a semi-aromatic polyamide film with a thickness of 50 μm. The film thickness was measured at 51 points (evenly spaced) in the width direction using a digital display meter (HEIDENHAIN, ND287), and the average value of the obtained measurements was adopted.

[0129] Examples 2-9 and Comparative Examples 1-8: Semi-aromatic polyamide films were obtained in the same manner as in Example 1, except that the content of heat stabilizers a and b or c, the heat-fixing temperature, the relaxation rate, and the film thickness were changed, as shown in Table 2.

[0130] Table 2 shows the composition of the semi-aromatic polyamide films produced in Examples 1 to 9 and Comparative Examples 1 to 8, the film production conditions, and the properties of the obtained semi-aromatic polyamide films.

[0131]

[0132] The semi-aromatic polyamide compositions of Examples 1 to 9 contained a hindered phenol-based heat stabilizer and a hindered amine-based heat stabilizer, which suppressed viscosity increases at high temperatures and inhibited the formation of gel-like substances during melt extrusion, resulting in low pressure increases in the extrusion filter and excellent continuous film production capabilities.

[0133] The semi-aromatic polyamide films of Examples 1 to 9 exhibited excellent tensile strength, high fracture resistance, low yellowness, high transparency and achromaticity, low thermal shrinkage in high-temperature atmospheres, excellent dimensional stability, and high retention of tensile elongation in high-temperature and high-humidity atmospheres, as well as excellent heat and humidity resistance.

[0134] On the other hand, the semi-aromatic polyamide compositions of Comparative Examples 1 to 8 did not contain hindered phenol-based heat stabilizers or hindered amine-based heat stabilizers, resulting in a large increase in viscosity at high temperatures, and the formation of gel-like material during melt extrusion caused a high pressure increase in the extrusion filter, resulting in poor continuous film productivity.

[0135] The semi-aromatic polyamide film of Comparative Example 1 exhibited poor dimensional stability due to its high thermal shrinkage rate in a high-temperature atmosphere because the temperature during the heat-setting treatment was low. The semi-aromatic polyamide films of Comparative Examples 5 and 6 exhibited poor retention of tensile elongation at break in a high-temperature, high-humidity atmosphere and poor resistance to humid heat. Furthermore, the semi-aromatic polyamide films of Comparative Examples 1 to 8 had low tensile strength and poor break resistance because a large amount of gel-like material was present within the film.

Claims

1. A semi-aromatic polyamide composition containing a semi-aromatic polyamide, a hindered phenol-based heat stabilizer, and a hindered amine-based heat stabilizer.

2. The semi-aromatic polyamide composition according to claim 1, wherein the content of the hindered phenol-based heat stabilizer is 0.5 to 10 parts by mass per 1 part by mass of the hindered amine-based heat stabilizer.

3. The semi-aromatic polyamide composition according to claim 1, wherein the content of the hindered phenol-based heat stabilizer is 0.1 to 1.5% by mass.

4. The semi-aromatic polyamide composition according to claim 1, wherein the semi-aromatic polyamide is at least one selected from the group consisting of polyamide 6T, polyamide 9T, polyamide 10T, and polyamide 9N.

5. A semi-aromatic polyamide film obtained from the semi-aromatic polyamide composition described in claim 1.

6. The following physical properties (1) to (4): (1) The thermal shrinkage rate S in the longitudinal direction of the film, which is determined by measuring the dimensions after heat treatment in an atmosphere of 250°C for 5 minutes, and then leaving it at a temperature of 23°C and humidity of 50% RH for 2 hours. MD and thermal shrinkage coefficient S in the width direction TD The semi-aromatic polyamide film according to claim 5, satisfying all of the following: (1) the respective values ​​are -1.0 to 1.5%, (2) the retention rate of the tensile break elongation in the longitudinal and width directions of the film after moist heat treatment for 120 hours at a temperature of 121°C and a humidity of 100% RH is 80% or more, (3) the yellowness (YI) is 10 or less in absolute value, and (4) the tensile break strength in the longitudinal and width directions of the film is 150 MPa or more.

7. An electronic material having a semi-aromatic polyamide film according to claim 5 or 6.

8. An optical component having the semi-aromatic polyamide film according to claim 5 or 6.

9. A photovoltaic module having the semi-aromatic polyamide film according to claim 5 or 6.

10. A method for producing a semi-aromatic polyamide film according to claim 5 or 6, comprising the steps of: obtaining an unstretched film from the semi-aromatic polyamide composition according to claim 1; stretching the unstretched film to obtain a stretched film; and subjecting the stretched film to a heat-fixing treatment at a temperature of the melting point (Tm) of the semi-aromatic polyamide - (10 to 22°C).

11. A method for producing a semi-aromatic polyamide film according to claim 10, comprising the step of subjecting a heat-fixed stretched film to a relaxation treatment.

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