KR20230093805A - Polyester resin composition, polyester film, and flexible flat cable - Google Patents

Abstract

The polyester resin composition according to the embodiment includes a polyester resin, an application agent and an antioxidant, the diol residue includes a cyclohexanedimethanol residue, the dicarboxylic acid residue includes a terephthalic acid residue, and the application The weight ratio of agent and antioxidant is 1:0.01 to 20.
The polyester film according to the embodiment has a b* value of 5 or less in the CIELAB color space after being left at 150° C. for 2 weeks.
The polyester resin composition, polyester film, etc. according to the embodiment have excellent properties such as heat resistance, durability, and optical properties, and are used in the manufacture of flexible flat cables requiring durability due to repeated exposure to heat to obtain more excellent properties It is possible to provide a flexible flat cable having.

Description

Polyester resin composition, polyester film and flexible flat cable {POLYESTER RESIN COMPOSITION, POLYESTER FILM, AND FLEXIBLE FLAT CABLE}

Embodiments relate to a polyester resin composition having excellent oxidation stability, durability, optical properties, etc. by appropriately adding an applicator and an antioxidant, a polyester film, and a flexible flat cable including the same.

Recently, metal materials are being replaced with plastic materials to reduce the weight of electrical and electronic devices such as automobiles. A flexible flat cable (FFC), one of automobile parts, is a type of connection cable used to connect between printed circuit boards (PCBs) or printed board assemblies (PBAs). thin. In addition, since the flexible flat cable is flexible and can be folded, it is widely used as a connection connector inside electronic devices such as mobile phones.

As the plastic material, a polyethylene terephthalate (PET) stretched film has low heat resistance, so it is difficult to use it for a flexible flat cable, which is a part requiring high heat resistance.

Republic of Korea Publication No. 10-2019-0059216 Republic of Korea Registration No. 10-2094283

An object of the embodiment is to provide a polyester resin composition and a polyester film having excellent oxidation stability, durability, and optical properties by appropriately adding an applicator and an antioxidant to the polyester film.

An object of the embodiment is to provide a polyester film or the like that can be utilized in manufacturing a flexible flat cable or the like.

In order to achieve the above object, the polyester resin composition of one embodiment includes a polyester resin, an application agent and an antioxidant, the polyester resin includes a diol residue and a dicarboxylic acid residue, and the diol residue is cyclo hexanedimethanol residues, the dicarboxylic acid residues contain terephthalic acid residues, and the weight ratio of the applying agent and antioxidant is 1:0.01 to 20.

The antioxidant may include a phenol-based antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant.

The applicator may be included in an amount of 200 ppm or more based on the total weight of the polyester resin composition.

The applicator may include the first metal salt and the second metal salt in a weight ratio of 1:1 to 10.

The first metal salt may include an alkali metal salt, and the second metal salt may include an alkaline earth metal salt.

Each of the first metal salt, the second metal salt, the alkali metal salt and the alkaline earth metal salt may be included in the polyester resin composition in an ionized state.

In order to achieve the above object, another embodiment of the polyester film is a polyester resin; an applicator or a reactant thereof; and an antioxidant or a reactant thereof, the polyester resin comprising a diol residue and a dicarboxylic acid residue, the diol residue comprising a cyclohexanedimethanol residue, and the dicarboxylic acid residue comprising a terephthalic acid residue. include

The polyester film may have a b* value of 5 or less in the CIELAB color space after being left at 150° C. for 2 weeks.

The polyester film may have a b* value difference (absolute value) of 5 or less before and after being left at 150 °C for 2 weeks.

L* is a value in the CIELAB color space, and the difference (absolute value) of L* before and after the polyester film is allowed to stand at 150° C. for 2 weeks may be 2 or less.

The polyester film may not be cracked after being left at 150 ° C. for one week.

The applicator may include a first metal salt and a second metal salt.

The first metal salt includes an alkali metal salt, and the second metal salt includes an alkaline earth metal salt.

The metal of the first metal salt and the metal of the second metal salt may be included in a weight ratio of 1:1 to 10.

Each of the first metal salt, the second metal salt, the alkali metal salt and the alkaline earth metal salt is contained in an ionized state in the polyester film, and each of the metal of the first metal salt and the metal of the second metal salt is Contains metal ions in an ionized state.

In order to achieve the above object, a flexible flat cable according to another embodiment includes at least one electrically conductive layer; and an insulating layer disposed to surround at least a portion of the electrically conductive layer, wherein the insulating layer includes the polyester film described above.

The polyester resin composition of the embodiment can be used to manufacture a polyester film having excellent properties such as oxidation stability, durability, and optical properties.

The polyester film of the embodiment has excellent oxidation stability, no cracking even under harsh conditions for a long period of time, and can maintain excellent optical properties.

The polyester film and the like of the embodiment can be utilized in parts for electric and electronic devices such as flexible flat cables to improve durability and properties such as optical properties.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Like reference numerals have been assigned to like parts throughout the specification.

In this specification, when a certain component "includes" another component, this means that it may further include other components without excluding other components unless otherwise specified.

In this specification, when a component is said to be "connected" to another component, this includes not only the case of being 'directly connected', but also the case of being 'connected with another component intervening therebetween'.

In this specification, the meaning that B is located on A means that B is located directly on A or B is located on A while another layer is located therebetween, and B is in contact with the surface of A. It is not construed as being limited to location.

In this specification, the meaning that B is located under A means that B is located under A directly in contact with B or B is located under A while another layer is located therebetween, and that B is located in contact with the surface of A. limited and not to be construed.

In this specification, the term "combination of these" included in the expression of the Markush form means a mixture or combination of one or more selected from the group consisting of the components described in the expression of the Markush form, It means including one or more selected from the group consisting of.

In this specification, the unit of ppm applied without special mention is based on weight.

It should be understood that all numerical ranges representing physical property values, dimensions, etc. of components described in this specification are modified by the term "about" in all cases unless otherwise specified.

In the present specification, "residue" means a certain part or unit derived from a specific compound and included in the result of the chemical reaction when a specific compound participates in a chemical reaction. For example, each of the dicarboxylic acid "residue" or the diol "residue" is a portion derived from a dicarboxylic acid component or a portion derived from a diol component in a polyester formed by an esterification reaction or a polycondensation reaction. can mean

Polyester films such as polyethylene terephthalate (PET) stretched films are used for manufacturing parts such as FFCs, but there is a limit to the heat resistance temperature of the film itself. Accordingly, the utilization of the stretched PET film and the like as an FFC applied to electrical and electronic device parts such as automobile power trains and engine control parts requiring high heat resistance is limited.

In addition, when manufacturing a polyester film, a metallic polymerization catalyst (Ti, etc.) is used to increase the activity of the polymerization reaction. Due to this, problems such as discoloration of the film in which it turns yellow rather than its original color and cracking may occur. To prevent this problem, antioxidants can be utilized.

On the other hand, an applicator is used for a film manufactured by an electrostatic application method. When an antioxidant and an application agent are applied together during film production, a problem of inhibiting each other's performance may occur due to an interaction between them.

Therefore, there is a need for a film that has no problems such as discoloration or breakage of the film while ensuring the efficiency of film production, and has improved oxidation stability and durability at the same time.

Hereinafter, an embodiment will be described in more detail.

polyester resin composition

In order to achieve the above object, a polyester resin composition according to an embodiment includes a polyester resin, an application agent and an antioxidant, wherein the polyester resin includes a diol residue and a dicarboxylic acid residue, and the diol residue is cyclohexanedimethanol residues, the dicarboxylic acid residues contain terephthalic acid residues, and the weight ratio of the application agent and antioxidant is 1:0.01 to 20.

The polyester resin may be prepared by a conventional polymerization method, and may be exemplarily polymerized under a metal-containing catalyst such as titanium or antimony.

The diol residue may include a cyclohexanedimethanol residue.

Specifically, the cyclohexanedimethanol residue may be a 1,4-cyclohexanedimethanol residue.

The polyester resin contains 50 mol% or more, 70 mol% or more, 80 mol% or more, 85 mol% or more, 90 mol% or more, 95 mol% or more, or 98 mol% or more. Also, the diol residue may be substantially composed of the cyclohexanedimethanol residue. When the above amount of the cyclohexanedimethanol residue is used as the diol residue, a polyester resin having improved heat resistance and hydrolysis resistance may be provided.

The diol residue may further include a diol residue other than a cyclohexanedimethanol residue. At this time, the polyester resin may be a co-polyester resin.

Specific examples of additional diol moieties include ethylene glycol, 1,3-propanediol, 1,2-octanediol, 1,3-octanediol, 2,3-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2-butyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1, Residues of 5-pentanediol, 2,4-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,1-dimethyl-1,5-pentanediol and mixtures thereof can

The dicarboxylic acid residue may include a terephthalic acid residue.

The dicarboxylic acid residue may be a terephthalic acid residue, an isophthalic acid residue, or a mixture thereof.

Specifically, the dicarboxylic acid residue may include a terephthalic acid residue and an isophthalic acid residue.

The content of the terephthalic acid residues may be 80 mol% or more, 90 mol% or more, 95 mol% or more, or 100 mol% or less when the total amount of the dicarboxylic acid residues is 100 mol%.

When the dicarboxylic acid residue includes a terephthalic acid residue and an isophthalic acid residue, the content of the isophthalic acid residue may be 20 mol% or less, and 15 mol% based on 100 mol% of the entire dicarboxylic acid residue. It may be less than, 10 mol% or less, may be 5 mol% or less. The content of the isophthalic acid residue may be 0 mol% or more, 1 mol% or more, 2 mol% or more, or 3 mol% or more.

When the dicarboxylic acid residue includes the terephthalic acid residue and the isophthalic acid residue in the above contents, it may have a relatively high melting point and low crystallization characteristics.

As the dicarboxylic acid residue, aromatic dicarboxylic acid residues such as dimethyl terephthalic acid, naphthalene dicarboxylic acid, and orthophthalic acid; aliphatic dicarboxylic acid residues such as adipic acid, azelaic acid, sebacic acid, and decane dicarboxylic acid; cycloaliphatic dicarboxylic acid residues; And it may further include one or more selected from the group consisting of residues of these esterified products.

The polyester resin may include 1,4-cyclohexanedimethylene terephthalate residues and 1,4-cyclohexanedimethylene isophthalate residues as repeating units. The polyester resin may include poly(1,4-cyclohexylenedimethylene terephthalate-co-isophthalate) (PCTA) resin.

The polyester resin may have a weight average molecular weight (Mw) of 30,000 g/mol to 50,000 g/mol or 30,000 g/mol to 40,000 g/mol.

The method for synthesizing the polyester resin is illustratively, mixing a monomer capable of constituting a dicarboxylic acid residue and a monomer capable of constituting a diol residue, and then inducing an esterification reaction or a condensation reaction to synthesize a polyester resin. can

A catalyst may be applied to the polyester resin to improve the efficiency of the polymerization reaction.

The catalyst may be applied in an amount of 0.00001 to 0.05 parts by weight and 0.00005 to 0.01 parts by weight based on 100 parts by weight of the polyester resin.

The catalyst may be a titanium-based compound, an antimony-based compound, a germanic compound, an aluminum-based compound, or a mixture thereof.

Specifically, the catalyst may be a titanium-based compound.

The titanium-based compound may include titanium tetraisopropoxide.

An antioxidant may be applied to the synthesis of the polyester resin. The antioxidant may be applied as necessary for the purpose of suppressing thermal oxidation at a temperature of about 275 ° C. at which the esterification reaction proceeds. However, it is common to apply only an appropriate amount of the antioxidant applied here. This is because, when a resin is synthesized by adding an excessive amount of an antioxidant, there is a high risk of delaying the polymerization reaction itself, and in many cases, a decrease in the intrinsic viscosity of the prepared resin occurs. Therefore, antioxidants that affect polyester resin synthesis are consumed in the synthesis process, and it is practically difficult to apply an excessive amount of antioxidants to an extent that affects film extrusion. Therefore, antioxidants applied to polyester resin compositions for the purpose of preventing oxidation during film production are substantially different from antioxidants applied during resin synthesis.

The synthesized polyester resin may be stored in the form of a chip and then utilized for manufacturing a polyester film.

The stored polyester resin may be subjected to a drying process before film production, and the drying may be performed at a temperature of 150 °C or less, and may be performed in an atmosphere of 70 to 148 °C. The drying may be performed such that the moisture content of the dried polyester resin is 100 ppm or less. Preferably, drying conditions are applied so that it is 50 ppm or less. When the drying process is performed at a temperature higher than 150° C., there is a concern that unintended color change may occur in the polyester resin itself.

The polyester resin composition may include an applicator.

The applicator may contribute to forming a film having a uniform thickness without a temperature gradient by adhering the sheet obtained by extruding the polyester resin composition to a cooling casting roll. In addition, the applicator may contribute to preventing excessive crystal formation of the film during annealing, suppressing non-uniform stretching, and preventing breakage.

The applying agent may include a first metal salt (including an ionized state; the same hereinafter) and a second metal salt (including an ionized state; hereinafter the same).

The first metal salt may include an alkali metal salt, and the second metal salt may include an alkaline earth metal salt.

Specifically, the first metal salt may include a potassium-based metal salt, and the second metal salt may include a magnesium-based metal salt.

More specifically, the potassium-based metal salt may be potassium acetate (C ₂ H ₃ O ₂ K), and the magnesium-based metal salt may be magnesium acetate (C ₄ H ₆ O ₄ Mg).

Each of the first metal salt, the second metal salt, the alkali metal salt, and the alkaline earth metal salt may include an ionized state.

Each of the potassium-based metal salt, the magnesium-based metal salt, the potassium acetate, and the magnesium acetate may include an ionized state.

Specifically, the metal salts described above, such as the first metal salt and the second metal salt, include both a state in which they are present in the polyester resin composition as they are and an ionized and separated state.

When the above compound is applied as the first metal salt and the second metal salt, it is possible to obtain effects such as maintaining transparency and preventing the formation of foreign substances while sufficiently performing the function as an applicator.

In the coating agent included in the polyester composition, the weight ratio of the first metal salt and the second metal salt is based on the weight of each metal salt (including ionized state; hereinafter the same) added.

In the polyester composition, the applicator may include the first metal salt and the second metal salt in a weight ratio of 1:1 to 10. Specifically, the applicator may include the first metal salt and the second metal salt in a weight ratio of 1:5 to 10, or 1:8 to 10. When the first metal salt and the second metal salt are applied in the above ranges, the function of the applicator can be sufficiently performed while the interaction with other additives can be substantially suppressed, and a film with improved durability and optical properties can be provided. can do.

An applicator may be included in an amount of 200 ppm or more based on the total weight of the polyester resin composition. Specifically, the applicator may be included in an amount of 300 ppm or more based on the entire polyester resin composition, and may be included in an amount of 350 ppm or more. The applicator may be included in an amount of 1000 ppm or less, 600 ppm or less, and 500 ppm or less based on the total weight of the polyester resin composition.

The polyester resin composition may include an antioxidant.

Antioxidants are usually applied to suppress unintended side reactions in chemical reactions, and are often applied mainly in the resin synthesis process.

In an embodiment, an antioxidant is applied to a resin composition including a resin that has already been synthesized. Through this, not only the basic function of suppressing side reactions in the filming process, but also the oxidation stability and durability of the manufactured film are improved, so that even if the film is exposed to harsh environments such as repeated heating and cooling during the process of use, the film's Aging can be substantially prevented. Due to these characteristics, the polyester film may have excellent utility as electrical and electronic device components such as flexible flat cables.

The polyester resin composition according to the embodiment may include three or more antioxidants.

Specifically, the antioxidant may include a phenol-based antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant.

Examples of the phenolic antioxidant include tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane; octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; benzenepromanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy,alkyl ester (alkyl has 7 or 9 carbon atoms); triethylene glycol-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate; tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate; 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; or a combination thereof.

The phosphorus-based antioxidant is exemplarily 3,9-bis (2,4-dicamylphenoxy) -2,4,8,10-tetraoxa-3,9-iphosphaspiro [5.5] undecane [3 ,9-Bis(2,4-dicumylphenoxy)-2,4,8,10-tetraoxa-3,9-iphosphaspiro[5.5]undecane]; bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol-di-phosphite; bis(2,4-di-tert-butylphenyl)pentaerythritol-di-phosphite; tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenylene diphosphonite; or a combination thereof.

The sulfur-based antioxidant is dilauryl-3,3'-thiodipropionic acid ester; Dimyristyl-3,3'-thiodipropionic acid ester; distearyl-3,3'-thiodipropionic acid ester; laurylstearyl-3,3'-thiodipropionic acid ester; pentaerythrityl tetrakis(3-laurylthiopropion ester); or a combination thereof.

The antioxidant may be applied together with three or more selected from those mentioned above.

The antioxidant may be included in an amount of 100 ppm or more, 500 ppm or more, 1000 ppm or more, or 3000 ppm or more based on the total weight of the polyester resin composition. The antioxidant may be included in an amount of 10000 ppm or less, 7000 ppm or less, and 5000 ppm or less based on the total weight of the polyester resin composition.

The phenolic antioxidant may be included in an amount of 40 ppm to 3000 ppm based on the total weight of the polyester resin composition.

The phosphorus-based antioxidant may be included in an amount of 40 ppm to 3000 ppm based on the total weight of the polyester resin composition.

The sulfur-based antioxidant may be included in an amount of 40 ppm to 3000 ppm based on the total weight of the polyester resin composition.

The antioxidant may include the phosphorus-based antioxidant and the sulfur-based antioxidant in a weight ratio of 1: 0.1 to 4, 1: may include a weight ratio of 0.4 to 2.2, and 1: may include a weight ratio of 0.8 to 1.2. can

The antioxidant may include the phosphorus-based antioxidant and the phenol-based antioxidant in a weight ratio of 1: 0.1 to 4, 1: may include a weight ratio of 0.4 to 2.2, and 1: included in a weight ratio of 0.8 to 1.2 can do.

Specifically, the antioxidant may include the phenol-based antioxidant, the phosphorus-based antioxidant, and the sulfur-based antioxidant in a weight ratio of 1: 0.5 to 1.5: 0.5 to 1.5.

When three or more antioxidants selected from those mentioned above are applied together in the above content or content ratio in the film manufacturing step, it is possible to substantially suppress the occurrence of cracking of the film even after harsh treatment of the manufactured film, and to be described later It is possible to further improve optical characteristics that appear according to color coordinates in the CIELAB color space.

The weight ratio of the applicator and the antioxidant may be 1:0.01 to 20. Specifically, the weight ratio of the applicator and the antioxidant may be 1: 2 to 15, 1: 4 to 13, 1: 7 to 11, or 1: 8 to 10. When the weight ratio of the applicator and the antioxidant is as described above, the interaction between each other is substantially suppressed, and durability and optical properties of the film can be further improved while sufficiently performing each function.

A method of processing and utilizing the polyester resin composition is not particularly limited, but utilization as a biaxially stretched film is most preferred.

polyester film

A polyester film according to an embodiment is a polyester resin; an applicator or a reactant thereof; and an antioxidant or a reactant thereof, the polyester resin comprising a diol residue and a dicarboxylic acid residue, the diol residue comprising a cyclohexanedimethanol residue, and the dicarboxylic acid residue comprising a terephthalic acid residue. and the b* value in the CIELAB color space is 5 or less after being left at 150° C. for 2 weeks.

A catalyst may be applied to the polyester resin during its polymerization reaction.

Detailed descriptions of the polyester resin, catalyst, diol residue, dicarboxylic acid residue, cyclohexanedimethanol residue, terephthalic acid residue, applying agent, antioxidant, etc. are omitted since they overlap with the above description.

The optical properties and durability of the polyester film can be confirmed by measuring color coordinate values in the CIELAB color space.

The CIELAB color space is a color value defined by the International Commission on Illumination (CIE), and is a color space that can almost match chrominance that can be detected by the naked eye and chrominance expressed numerically in the color space. it means.

Color coordinates in the CIELAB color space are represented by L*, a*, and b*.

The L* represents lightness, and the L* value is between 0 and 100. If the L* value is 0, it represents black, and if it is 100, it represents white (the color of the light source).

The a* represents the degree of red and green. Based on 0, the smaller (negative number) the value of a* is, the closer it is to green, and the larger (positive number), the closer it is to red.

The b* represents the degree of blue and yellow. Based on 0, the smaller (negative number) the b* value is, the closer it is to blue, and the larger (positive number), the closer it is to yellow.

The color coordinate values in the CIELAB color space can be measured by applying a general method of measuring each coordinate value in the color space. For example, it can be measured according to ASTM E308 using Hunter Lab's UltraScan PRO spectrophotometer.

The polyester film may have an L* value of 93 or more in the CIELAB color space after being left at 150 °C for 2 weeks. Specifically, the polyester film may have an L* value of 94 or more, 95 or more, 95.2 or more, 100 or less, 96 or less in the CIELAB color space after being left for 2 weeks at 150 ° C. , 95.3 or less.

The polyester film may have an L* value of 92 or more in the CIELAB color space after being left at 150° C. for 3 weeks. Specifically, the polyester film may have an L* value of 93 or more, 95 or more, 95.15 or more, 100 or less, 96 or less in the CIELAB color space after being left at 150 ° C. for 3 weeks. , 95.2 or less.

The polyester film may have an L* value difference (absolute value) of 2 or less before and after being left at 150 °C for 2 weeks. Specifically, the polyester film may have an L* value difference (absolute value) before and after being allowed to stand at 150 ° C. for 2 weeks may be 1 or less, may be 0.64 or less, may be 0.62 or less, may be 0.1 or more, may be 0.5 or more, , may be greater than or equal to 0.58.

The polyester film may have an L* value difference (absolute value) of 3 or less before and after being left at 150 °C for 3 weeks. Specifically, the polyester film may have a difference in L* value (absolute value) before and after being left at 150 ° C. for 3 weeks may be 2 or less, may be 0.8 or less, may be 0.68 or less, may be 0.1 or more, may be 0.5 or more, , may be greater than or equal to 0.63.

When the L* value of the polyester film is the same as above, the film maintains high brightness even after being left under harsh conditions, so that optical properties, durability, and the like may be excellent.

The polyester film may have an a* value of -0.7 or more in the CIELAB color space after being left at 150 °C for 2 weeks. Specifically, after the polyester film is left at 150 ° C. for 2 weeks, the a* value in the CIELAB color space may be -0.5 or more, -0.23 or more, -0.22 or more, 1 or less, and 0 It may be less than or equal to -0.2.

The polyester film may have an a* value of -1.2 or more in the CIELAB color space after being left at 150 °C for 3 weeks. Specifically, after the polyester film is left at 150° C. for 3 weeks, the a* value in the CIELAB color space may be -1 or more, -0.4 or more, -0.28 or more, 1 or less, and 0 It may be less than or equal to -0.1, or less than -0.26.

The polyester film may have a difference in a* value (absolute value) of 0.75 or less before and after being left at 150 °C for 2 weeks. Specifically, the polyester film may have a difference in a* value (absolute value) before and after being allowed to stand at 150 ° C. for 2 weeks may be 0.5 or less, may be 0.3 or less, may be 0.25 or less, may be 0.1 or more, may be 0.2 or more. .

The polyester film may have a difference in a* value (absolute value) of 1.3 or less before and after being left at 150 °C for 3 weeks. Specifically, the polyester film may have a difference in a* value (absolute value) before and after being allowed to stand at 150 ° C. for 3 weeks may be 1 or less, may be 0.5 or less, may be 0.4 or less, may be 0.3 or less, may be 0.1 or more, , may be greater than or equal to 0.2.

When the a* value of the polyester film is as described above, the red/green degree of the film is appropriately maintained even after being left under harsh conditions, and thus the film may have excellent optical properties and durability.

The polyester film may have a b* value of 5 or less in the CIELAB color space after being left at 150° C. for 2 weeks. Specifically, the polyester film may have a b* value of 3 or less, 1 or less, 0.9 or less, 0.8 or less, or 0.1 or more in the CIELAB color space after being left at 150 ° C. for 2 weeks. , may be greater than or equal to 0.5, and may be greater than or equal to 0.7.

The polyester film may have a b* value of 11 or less in the CIELAB color space after being left at 150° C. for 3 weeks. Specifically, the polyester film may have a b* value of 5 or less, 3 or less, 1.8 or less, 1.3 or less, 0.5 or more in the CIELAB color space after being left at 150 ° C. for 3 weeks. , may be 1 or more.

The polyester film may have a b* value difference (absolute value) of 5 or less before and after being left at 150 °C for 2 weeks. Specifically, the polyester film may have a b* value difference (absolute value) of 3 or less, 1 or less, 0.5 or less, 0.4 or less, 0.35 or less, before and after being left at 150 ° C. for 2 weeks. , may be greater than or equal to 0.1, and may be greater than or equal to 0.3.

The polyester film may have a b* value difference (absolute value) of 11 or less before and after being left at 150 °C for 3 weeks. Specifically, the polyester film may have a b* value difference (absolute value) before and after being allowed to stand at 150 ° C. for 3 weeks may be 5 or less, may be 1 or less, may be 0.9 or less, may be 0.7 or less, may be 0.1 or more, , may be greater than or equal to 0.6.

When the b* value of the polyester film is as described above, the blue/yellow degree of the film is appropriately maintained even after being left under harsh conditions, and thus the film may have excellent optical properties and durability. In particular, when a metal-containing catalyst such as titanium is applied, the film is oxidized and turns yellow due to the strong activity of the catalyst, and it is considered a very good value considering that it is not easy to suppress it.

Therefore, when the L*, a*, and b* values in the CIELAB color space of the polyester film left under severe conditions for a long period of time are the same as above, the optical properties such as brightness and transparency are excellent, and the heat resistance, durability, etc. this can be great

The polyester film may not be cracked after being left at 150 °C for 1 week. Specifically, the polyester film is left on a glass plate with tongs, etc., left inside the hot air for 5 minutes in the temperature atmosphere, then left at room temperature for 30 minutes to cool, visually evaluated whether it is broken by bending it at about 90 degrees Thus, cracking may not occur.

The polyester film may not be cracked after being left at 150 °C for 2 weeks, and may not be cracked after being left at 150 °C for 3 weeks. The evaluation method for crack occurrence is the same as described above.

The polyester film may include an applicator or a reactant thereof; and antioxidants or reactants thereof.

The applicator may contribute to forming a film having a uniform thickness without a temperature gradient by adhering the extruded sheet of the polyester resin composition to a cooling casting roll. In addition, the applicator may contribute to preventing excessive crystal formation of the film during annealing, suppressing non-uniform stretching, and preventing breakage.

The applying agent may include a first metal salt (including an ionized state; the same hereinafter) and a second metal salt (including an ionized state; hereinafter the same). The first metal salt may include an alkali metal salt, and the second metal salt may include an alkaline earth metal salt. Specifically, the first metal salt may include a potassium-based metal salt, and the second metal salt may include a magnesium-based metal salt. More specifically, the potassium-based metal salt may be potassium acetate (C ₂ H ₃ O ₂ K), and the magnesium-based metal salt may be magnesium acetate (C ₄ H ₆ O ₄ Mg).

Each of the first metal salt, the second metal salt, the alkali metal salt, and the alkaline earth metal salt may include an ionized state. Each of the potassium-based metal salt, the magnesium-based metal salt, the potassium acetate, and the magnesium acetate may include an ionized state.

Specifically, the metal salts described above, such as the first metal salt and the second metal salt, include both a state in which they exist in themselves as well as an ionized and separated state in the polyester resin film.

In the applicator or its reactant included in the polyester film, the metal weight of the first metal salt and the metal weight of the second metal salt are the weight of the metal (including ionized metal ions, hereinafter the same) detectable in the film. Based on weight.

The metal weight of the first metal salt and the metal weight of the second metal salt refer to the weight occupied by the metal in the total weight of each metal salt added. The weight occupied by the metal in the total metal salt may vary depending on the atomic weight and mole number of each metal. Therefore, the weight ratio of the first metal salt and the second metal salt added to the polyester resin composition or the like may be different from the weight ratio of the metal of the first metal salt and the metal of the second metal salt.

In the polyester film, the metal of the first metal salt and the metal of the second metal salt may be included in a weight ratio of 1:1 to 10. Specifically, the metal of the first metal salt and the metal of the second metal salt may be included in a weight ratio of 1:2 to 6, may be included in a weight ratio of 1:3 to 5, and may be included in a weight ratio of 1:3 to 4. .

Each of the metal of the first metal salt and the metal of the second metal salt may include a metal ion in an ionized state.

An applicator may be included in an amount of 200 ppm or more based on the entirety of the polyester film. Specifically, the applicator may be included in an amount of 300 ppm or more based on the entirety of the polyester film, and may be included in an amount of 400 ppm or more. The applicator may be included in an amount of 1000 ppm or less, 600 ppm or less, and 500 ppm or less based on the entirety of the polyester resin film.

Detailed description of the type, example, content, content ratio, etc. of the applicator overlaps with the above description, so description thereof will be omitted.

Antioxidants act to slow down the degree of oxidation of the resin and suppress aging by reacting to energy such as heat and ultraviolet light applied from the outside to the film during or after film production before the resin. In the embodiment, better durability was obtained by specifying the type of antioxidant.

Three types of antioxidants can be used together as antioxidants, and detailed descriptions of examples, contents, and content ratios of phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants are the same as those described above, so descriptions thereof are omitted.

Antioxidants are added to the composition prior to film production or during film production. Therefore, the antioxidant itself may remain in the produced polyester film, and the reactant may remain. Hereinafter, the content of the antioxidant included in the polyester film is the content including both (1) the form of the antioxidant itself is maintained and (2) a identifiable reactant thereof.

The antioxidant may be included in an amount of 100 ppm or more, 500 ppm or more, 1000 ppm or more, or 3000 ppm or more based on the total weight of the polyester film. The antioxidant may be included in an amount of 10000 ppm or less, 7000 ppm or less, and 5000 ppm or less based on the total weight of the polyester film.

The phenolic antioxidant may be included in an amount of 40 ppm to 3000 ppm based on the total weight of the polyester film. The phosphorus-based antioxidant may be included in an amount of 40 ppm to 3000 ppm based on the entirety of the polyester film. The sulfur-based antioxidant may be included in an amount of 40 ppm to 3000 ppm based on the total weight of the polyester resin film. The content of the antioxidant may be calculated as the sum of the residual antioxidant and its decomposition product.

The antioxidant may include the phosphorus-based antioxidant and the sulfur-based antioxidant in a weight ratio of 1: 0.1 to 4, 1: may include a weight ratio of 0.4 to 2.2, and 1: may include a weight ratio of 0.8 to 1.2. can

The antioxidant may include the phosphorus-based antioxidant and the phenol-based antioxidant in a weight ratio of 1: 0.1 to 4, 1: may include a weight ratio of 0.4 to 2.2, and 1: included in a weight ratio of 0.8 to 1.2 can do.

Specifically, the antioxidant may include the phenol-based antioxidant, the phosphorus-based antioxidant, and the sulfur-based antioxidant in a weight ratio of 1: 0.5 to 1.5: 0.5 to 1.5.

When three or more antioxidants are applied together in the above content or ratio of the content in the film production step, the film does not break even after harsh treatment of the produced film, and the color coordinates in the CIELAB color space characteristics, etc. may be excellent.

A difference may occur between the content of the antioxidant administered to the polyester resin composition and the content of the antioxidant measured in the prepared polyester film. This is because, as described above, the antioxidant itself is easily decomposed, and in the case of sulfur-based antioxidants, in particular, decomposition products may be removed in gaseous form. Therefore, based on the phosphorus-based antioxidant and its decomposition product in the polyester film, the sulfur-based antioxidant can be detected in a weight ratio of 2 times or less.

The weight ratio of the applicator and the antioxidant may be 1:0.01 to 20. Specifically, the weight ratio of the applicator and the antioxidant may be 1: 2 to 15, 1: 4 to 13, 1: 7 to 11, or 1: 8 to 10. When the weight ratio of the applicator and the antioxidant is as described above, the interaction between the applicator and the antioxidant is substantially suppressed, so that durability and optical properties of the film can be further improved while sufficiently performing each function.

The polyester film may have a thickness of 1 μm to 1,000 μm and 10 μm to 500 μm. Specifically, the thickness of the polyester film may be 1000 μm or less, may be 500 μm or less, may be 250 μm or less, may be 150 μm or less, may be 100 μm or less, may be 80 μm or less, may be 60 μm or less It may be 1 μm or more, 10 μm or more, or 40 μm or more.

When the thickness of the polyester film is as described above, mechanical properties and the like are maintained within a practically usable range.

In the present specification, when presenting physical properties having different values depending on the thickness without specific reference to the thickness, a sample having a thickness of 50 μm is used as a reference.

The polyester film can be used as an insulating layer surrounding the electrically conductive layer, and can maintain relatively stable physical properties for a long period of time even when repeatedly exposed to high heat generated by the electrically conductive layer.

In addition, the polyester film is excellently maintained in optical properties such as transparency even under severe conditions, and is excellent in utilization as a component of an electric and electronic device requiring optical properties.

Manufacturing method of polyester film

The manufacturing method of the said polyester film is demonstrated.

The method of manufacturing the polyester film includes a sheet forming step of forming a sheet by extruding a polyester resin composition including a polyester resin in which diol and dicarboxylic acid are polymerized, an applicator and an antioxidant; and a stretching step of stretching the sheet in the longitudinal and width directions and heat-setting the stretched sheet.

The polyester resin included in the polyester resin composition may be dried. The drying is performed before the extrusion process. The drying temperature is preferably 150 ℃ or less to prevent color change. The extrusion may be performed at a temperature of 230 °C to 300 °C, or 250 °C to 290 °C.

Stretching is applied after preheating. The preheating may be performed in a range satisfying Tg + 5 ° C to Tg + 50 ° C based on the glass transition temperature (Tg) of the polyester resin, and may be performed in a range satisfying Tg + 10 ° C to Tg + 20 ° C. can Illustratively, the preheating may be performed in the range of 70 °C to 90 °C. In this case, it is possible to secure the flexibility necessary for the stretching of the polyester film and suppress a phenomenon in which the polyester film is broken during the stretching process.

The stretching may be performed by biaxial stretching. For example, it may be biaxially stretched in the longitudinal direction (machine direction, MD) and the width direction (tenter direction, TD) through a simultaneous biaxial stretching method or a sequential biaxial stretching method. Preferably, a sequential biaxial stretching method of first stretching in one direction and then stretching in a direction perpendicular to that direction may be performed.

The stretching ratio in the longitudinal direction may be 2.0 to 5.0, 3.0 to 3.5, or 3.1 to 3.3. Also, the stretch ratio in the width direction may be 3.0 to 5.0, 3.3 to 4.7, 3.7 to 4.1, or 3.8 to 4.0. In this case, mechanical properties and the like of the film can be further improved.

A ratio (d1/d2) of the stretching ratio (d1) in the width direction to the stretching ratio (d2) in the longitudinal direction may be 0.9 to 1.4 or 1.1 to 1.3. The stretching ratios d1 and d2 represent the length after stretching when the length before stretching is 1.0.

The stretching speed may be 6.5 m/min to 8.5 m/min.

The stretched sheet may be heat-set, and the heat-set temperature may be 150 °C to 250 °C, 230 °C to 250 °C, specifically 235 °C to 245 °C. The heat setting may be performed for 5 seconds to 10 minutes, and more specifically, for 10 seconds to 7 minutes.

After starting the heat setting, the film may be relaxed in the longitudinal direction and/or the width direction, and the temperature range at this time may be 150 °C to 250 °C, and the relaxation rate may be 1% to 10%, or 3% to 7%. can

In the manufacturing method, a sheet is prepared by appropriately mixing a polyester resin, an application agent, and an antioxidant, and a film having a substantially high stretching ratio and high mechanical strength (tensile strength, etc.) is provided by applying an appropriate temperature and stretching ratio. can In addition, a film that has undergone processes such as stretching and heat setting has excellent characteristics in terms of optical properties and durability.

Laminates for electrical and electronic devices (flexible flat cables, etc.)

A laminate for an electrical and electronic device according to an embodiment has a multilayer structure, and includes at least one electrically conductive layer; and an insulating layer disposed to surround at least a portion of the electrically conductive layer, wherein the insulating layer includes the polyester film described above.

Specifically, the laminate for electric and electronic devices may be a flexible flat cable.

The electrical and electronic device laminate includes an electrically conductive layer disposed on a first insulating layer; and a second insulating layer disposed on the electrically conductive layer. The laminate may be seen in a form in which the first insulating layer and the second insulating layer are substantially not distinguished and surround the electrically conductive layer.

Each of the first insulating layer and the second insulating layer may include the polyester film described above. Illustratively, the polyester film may be applied to a layer in direct contact with the electrically conductive layer, but is not limited thereto.

The electrically conductive layer may be exemplarily made of copper, silver, platinum, electrically conductive polymer, or a mixture thereof, and may be applied in the form of a wire or a thin film. Illustratively, a copper wire or the like may be applied, but is not limited thereto.

The polyester film has improved oxidation resistance, durability, durability, etc., and is more usable as an insulation layer of a flexible flat cable that can be more stably applied to major parts such as automobile powertrains and engine control parts where relatively high temperatures occur. .

Hereinafter, it will be described in more detail through specific examples. The following examples are merely examples to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

(1) Preparation of polyester resin and resin composition

A monomer mixture of 100 mol% of cyclohexanedimethanol (CHDM) as a diol and 96 mol% of terephthalic acid (TPA) and 4 mol% of isophthalic acid (IPA) as a dicarboxylic acid was added to the stirrer, After adding 0.0001 part by weight of Ti catalyst based on 100 parts by weight of the monomer mixture, transesterification was performed at 275 °C. After transferring the reactant to a separate reactor equipped with a vacuum facility, polymerization was performed at 285° C. for 160 minutes to obtain polycyclohexylene dimethylene terephthalate (PCT) resin. The resin was dried at a temperature of 150 ° C or lower and then applied to the subsequent process. The PCT resin thus prepared was applied as a polyester resin in Examples 1 to 6 and Comparative Examples below.

To the polyester resins of Examples and Comparative Examples, an applicator and/or an antioxidant were added in the amounts shown in Table 1 below.

As the applicator, a mixture of potassium acetate (C ₂ H ₃ O ₂ K) and magnesium acetate (C ₄ H ₆ O ₄ Mg) at a weight ratio of 1:9 was applied.

As the antioxidant, a phenol-based antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant were added in a weight ratio of 1:1:1.

As the phenolic antioxidant, Irganox 1010 from BASF was applied.

As the phosphorus-based antioxidant, Doverphos S9228 from Dover was applied.

As the sulfur-based antioxidant, AO-412S from Adeka was applied.

(2) Manufacture of polyester film

Example 1

As shown in Table 1 below, a total of 400 ppm of the coating agent and a total of 1000 ppm of an antioxidant were added to the polyester resin. This was put into an extruder, extruded at about 290 ° C, and cast at about 20 ° C with a casting roll to form a sheet. After preheating, the sheet was stretched in the machine direction (MD) and width direction (TD) at a temperature of 110 °C. Thereafter, the stretched sheet was heat-set for about 30 seconds and then relaxed to prepare each polyester film. The stretching ratio and heat setting temperature are shown in Table 1 below.

Examples 2 to 6

Other conditions are the same as in Example 1, but polyester films of Examples 2 to 6 were prepared with the content and composition according to [Table 1], respectively.

Comparative Example 1

Other conditions were the same as in Example 1, but a polyester film was prepared without adding an antioxidant.

Authorization system
Content (ppm) Antioxidant content (ppm) content ratio
(applied agent: antioxidant) stretch ratio
(MD X TD) heat fixation
Temperature (℃) Comparative Example 1 400 - 1 : 0.0 3.2 X 3.9 240 Example 1 400 1000 1:2.5 3.2 X 3.9 240 Example 2 400 2000 1:5.0 3.2 X 3.9 240 Example 3 400 3000 1:7.5 3.2 X 3.9 240 Example 4 400 4000 1:10.0 3.2 X 3.9 240 Example 5 500 4000 1:8.0 3.2 X 3.9 240 Example 6 600 4000 1:6.6 3.2 X 3.9 240

(3) Evaluation of physical properties of polyester film

1) Evaluation of CIELAB color space coordinate values

After leaving the prepared polyester film at 150 degrees for 3 weeks, the value in the LAB space was evaluated. The results of the L*, a*, and b* values measured weekly according to ASTM E308 using Hunter Lab's UltraScan PRO spectrophotometer are shown in Tables 2 to 4 below, and the differences from the initial values are shown in Table 5.

L* Early 1 week 2 weeks 3 weeks Comparative Example 1 95.93 94.65 92.88 91.77 Example 1 95.96 95.79 94.62 93.01 Example 2 95.95 95.82 95.3 95.1 Example 3 95.95 95.86 95.35 95.26 Example 4 95.84 95.77 95.26 95.17 Example 5 95.83 95.8 95.22 95.2 Example 6 95.67 95.58 95.1 94.98

a* Early 1 week 2 weeks 3 weeks Comparative Example 1 0.02 -0.36 -0.76 -0.75 Example 1 0.04 -0.03 -0.68 -1.2 Example 2 0.05 0 -0.28 -0.43 Example 3 0.05 0 -0.23 -0.27 Example 4 0.03 0.03 -0.2 -0.26 Example 5 0.03 0.01 -0.21 -0.26 Example 6 0.05 0.01 -0.26 -0.29

b* Early 1 week 2 weeks 3 weeks Comparative Example 1 0.28 4.74 9.26 13.59 Example 1 0.29 0.81 3.88 10.83 Example 2 0.33 0.59 0.87 1.93 Example 3 0.28 0.52 0.67 1.11 Example 4 0.38 0.54 0.71 1.21 Example 5 0.39 0.53 0.71 1.03 Example 6 0.49 0.7 0.94 1.4

ΔL* Δa* Δb* 1 week 2 weeks 3 weeks 1 week 2 weeks 3 weeks 1 week 2 weeks 3 weeks Comparative Example 1 1.28 3.05 4.16 0.38 0.78 0.77 4.46 8.98 13.31 Example 1 0.17 1.34 2.95 0.07 0.72 1.24 0.52 3.59 10.54 Example 2 0.13 0.65 0.85 0.05 0.33 0.48 0.26 0.54 1.6 Example 3 0.09 0.6 0.69 0.05 0.28 0.32 0.24 0.39 0.83 Example 4 0.07 0.58 0.67 0 0.23 0.29 0.16 0.33 0.83 Example 5 0.03 0.61 0.63 0.02 0.24 0.29 0.14 0.32 0.64 Example 6 0.09 0.57 0.69 0.04 0.31 0.34 0.21 0.45 0.91

2) Durability evaluation (breaking evaluation)

The prepared polyester film was cut into a size of 100 mm x 100 mm, left in OVEN at 150 ° C. for 1 week, 2 weeks, and 3 weeks, respectively (hereinafter referred to as oven treatment), and then left at room temperature for 30 minutes to cool. Thereafter, when the film was bent at about 90 degrees, it was visually evaluated whether or not cracking occurred, and shown in Table 6 below. It was evaluated as O if there was no cracking and maintaining excellent durability, X if there was a problem in durability due to cracking, and △ if it was in the middle.

durability 1 week 2 weeks 3 weeks Comparative Example 1 X X X Example 1 O X X Example 2 O O X Example 3 O O X Example 4 O O O Example 5 O O O Example 6 O O △

Referring to [Table 1] and [Table 2] to [Table 5], compared to Comparative Examples in which antioxidants were not added, examples in which a biaxially oriented polyester film was prepared by adding an applicator and an antioxidant in an appropriate ratio In the case of 1 to 6, optical properties, such as L*, a*, b* values, etc. in the CIELAB color space after harsh treatment were found to be excellent. In addition, in the case of Examples 1 to 6, the change in L*, a*, and b* values before and after harsh treatment was small compared to the comparative example, and durability was also excellent.

Referring to [Table 1] and [Table 6], in the case of Examples 1 to 6 in which the applicator and antioxidant were added in an appropriate ratio compared to the comparative example in which antioxidant was not added, cracking occurred over a long period of time even after harsh treatment It has been shown to have excellent durability. In addition, even between Examples 1 to 6, long-term durability evaluation (breakage evaluation) results were different.

The above results are due to the fact that when the antioxidant and the application agent are added together in an appropriate ratio, the interaction between each other is suppressed to maintain each function excellently, and the heat resistance, durability, optical properties, etc. of the film are relatively excellent. It is judged to have followed

In particular, in the case of Examples 4 and 5, the optical properties and durability (low color coordinate value difference) represented by the CIELAB color space were the best, and the long-term durability represented by the tear evaluation was also the best.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also made according to the present invention. falls within the scope of the rights of

Claims (10)

Contains a polyester resin, a coating agent and an antioxidant,
The polyester resin contains a diol residue and a dicarboxylic acid residue,
the diol moiety comprises a cyclohexanedimethanol moiety;
The dicarboxylic acid residue includes a terephthalic acid residue,
The weight ratio of the applicator and antioxidant is 1: 0.01 to 20,
A polyester resin composition.
According to claim 1,
The antioxidant is a polyester resin composition comprising a phenol-based antioxidant, a phosphorus-based antioxidant and a sulfur-based antioxidant.
According to claim 1,
The applicator is included in 200 ppm or more based on the total polyester resin composition, the polyester resin composition.
According to claim 1,
The applicator includes a first metal salt and a second metal salt in a weight ratio of 1:1 to 10,
The first metal salt includes an alkali metal salt,
The second metal salt includes an alkaline earth metal salt,
Each of the first metal salt, the second metal salt, the alkali metal salt and the alkaline earth metal salt is included in its ionized state,
A polyester resin composition.
polyester resin;
an applicator or a reactant thereof; and
Contains an antioxidant or a reactant thereof;
The polyester resin contains a diol residue and a dicarboxylic acid residue,
the diol moiety comprises a cyclohexanedimethanol moiety;
The dicarboxylic acid residue includes a terephthalic acid residue,
After being left at 150 ° C. for 2 weeks, the b* value in the CIELAB color space is 5 or less,
polyester film.
According to claim 5,
A polyester film having a difference in b* value (absolute value) of 5 or less before and after being left at 150 ° C. for 2 weeks.
According to claim 5,
L* is a value in the CIELAB color space,
A polyester film having an L* difference (absolute value) of 2 or less before and after being left at 150 ° C. for 2 weeks.
According to claim 5,
The polyester film is a polyester film that does not break after being left for 1 week at 150 ° C.
According to claim 5,
The applicator includes a first metal salt and a second metal salt,
The first metal salt includes an alkali metal salt,
The second metal salt includes an alkaline earth metal salt,
The metal of the first metal salt and the metal of the second metal salt are included in a weight ratio of 1:1 to 10,
Each of the first metal salt, the second metal salt, the alkali metal salt and the alkaline earth metal salt includes an ionized state,
Each of the metal of the first metal salt and the metal of the second metal salt includes a metal ion in its ionized state,
polyester film.
at least one electrically conductive layer; and
Including; an insulating layer disposed to surround at least a portion of the electrically conductive layer;
The insulating layer comprises a polyester film according to claim 5,
Flexible flat cable.