KR20240006278A - Preperation method of film and film - Google Patents

Abstract

The embodiment relates to a film manufacturing method, film, etc., and includes a sheet forming step of forming a composition for a film into a sheet; A film forming step of obtaining a film by biaxially stretching the sheet in the machine direction and the width direction, wherein the film composition includes polycyclohexylenedimethylene terephthalate resin; and polyethylene isosorbide cyclohexylenedimethylene terephthalate resin, wherein the longitudinal tear strength of the film is 270 N/mm or more.
The film increases the glass transition temperature by blending a heterogeneous resin with polycyclohexylenedimethylene terephthalate resin, which is difficult to control crystallization, improves heat resistance, makes it easier to control the degree of crystallization, and has improved tear strength. It provides a film with excellent physical properties such as

Description

Film manufacturing method and film {PREPERATION METHOD OF FILM AND FILM}

Embodiments relate to a method and film for manufacturing a film with improved tear strength, processability, etc.

Polyester has stable properties in terms of heat resistance, mechanical strength, transparency, etc. For this reason, it is widely used in various fields such as containers, packaging materials, films, and cables. In particular, PCT (Polycyclohexylenedimethylene Terephthalate) has superior heat resistance and moisture resistance compared to other resins, and its use is increasing in fields that require high heat resistance, especially in the field of electric vehicles and electrical components.

PCT resin can be produced by condensation polymerization of cyclohexanedimethanol and terephthalic acid.

PCT resin has rapid crystallization characteristics. These characteristics can help improve processability and production efficiency in the manufacture of injection molded products. However, in extrusion and stretching processes, these crystallization characteristics may cause a decrease in production yield.

The above-mentioned background technology is technical information that the inventor possessed for deriving the present invention or acquired in the process of deriving the present invention, and cannot necessarily be said to be known art disclosed to the general public before filing this application.

Related prior art includes Domestic Patent Publication No. 10-2022-0053850 and Domestic Patent Publication No. 10-2020-0128095.

The purpose of the embodiment is to provide a film manufacturing method and film with improved tear strength, processability, etc.

A method for manufacturing a film, which is an embodiment for achieving the above object, includes a sheet forming step of forming a composition for a film into a sheet; A film forming step of obtaining a film by biaxially stretching the sheet in the machine direction and the width direction, wherein the film composition includes polycyclohexylenedimethylene terephthalate resin; and polyethylene isosorbide cyclohexylenedimethylene terephthalate resin, and the longitudinal tear strength of the film is 270 N/mm or more.

The film composition may include the polycyclohexylenedimethylene terephthalate resin and polyethylene isosorbide cyclohexylenedimethylene terephthalate resin in a weight ratio of 1:0.1 to 0.5.

The film forming step includes a machine direction stretching process of stretching the sheet in the machine direction at a first stretching temperature and a first stretching ratio; and a width direction stretching process of obtaining a stretched sheet by stretching the sheet in the width direction at a second stretching temperature and a second stretching ratio. may include.

The first stretching temperature may be 80°C to 100°C.

The first stretching ratio may be 3.0 to 3.5.

The second stretching temperature may be 200°C to 240°C.

The second stretching ratio may be 3.5 to 3.9.

The sheeting step may include an extrusion process of extruding the film composition at an extrusion temperature.

The extrusion temperature may be 250°C to 300°C.

A film according to another embodiment includes polycyclohexylenedimethylene terephthalate resin; and polyethylene isosorbide cyclohexylenedimethylene terephthalate resin.

The longitudinal tear strength of the film may be 270 N/mm or more.

The glass transition temperature of the film may be 93°C or higher.

The ratio of the polycyclohexylenedimethylene terephthalate resin and the polyethylene isosorbide cyclohexylenedimethylene terephthalate resin may be 1:0.1 to 0.5.

The film may have a tear strength in the width direction of 300 N/mm or more.

The film may have a difference between longitudinal tear strength and width direction tear strength of 70 N/mm or less.

The polycyclohexylenedimethylene terephthalate resin includes a diol-based repeating unit and a dicarboxylic acid-based repeating unit, and when the total carboxylic acid-based residue is considered 100% by weight, the isophthalic acid residue is 0 to 20% by weight. It can be included.

The film manufacturing method and film of the embodiment provide a film with improved tear strength, processability, etc., and a manufacturing method thereof. The film increases the glass transition temperature by blending a heterogeneous resin with polycyclohexylenedimethylene terephthalate resin, which is difficult to control crystallization, improves heat resistance, makes it easier to control the degree of crystallization, and has improved tear strength. It provides a film with excellent physical properties such as

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Throughout the specification, similar parts are given the same reference numerals.

As used herein, the terms "about", "substantially", etc. are used to mean at or close to the numerical value when manufacturing and material tolerances inherent in the stated meaning are presented, and to aid understanding of the embodiments. It is used to prevent unscrupulous infringers from unfairly exploiting disclosures in which precise or absolute figures are mentioned.

Throughout this specification, the term "combination thereof" included in the Markushi format expression means a mixture or combination of one or more components selected from the group consisting of the components described in the Markushi format expression, It means including one or more selected from the group consisting of.

Throughout this specification, description of “A and/or B” means “A, B, or A and B.”

Throughout this specification, terms such as “first”, “second” or “A” and “B” are used to distinguish the same terms from each other unless otherwise specified.

In this specification, B is located on A, which means that B is located on A or B can be located on A with another layer located in between, and B is located in contact with the surface of A. It is not interpreted as limited to doing so.

In this specification, singular expressions are interpreted to include singular or plural as interpreted in context, unless otherwise specified.

In this specification, room temperature means 20°C to 25°C.

The resin described herein is interpreted to include the resin itself and compounds derived from the resin. Illustratively, the polyester resin described herein is interpreted to include polyester resin and derivatives of the polyester resin.

The '~-based repeating unit' described in this specification refers to a repeating unit (residue) derived from a compound applied as a monomer. By way of example, the diol-based repeating unit refers to a repeating unit (residue) derived from a diol-based compound.

Polycyclohexylene-dimethylene terephthalate (PCT) is a resin that has excellent physical properties and is being studied for various possible uses for injection molding. However, because it has the characteristic of rapid crystallization, it is not easy to form into a film, making production difficult despite its high usability. In addition, the breakability of the film may increase due to various causes such as rapid crystallization, which can fatally lower the processability. The inventors studied a method to improve the efficiency of film formation and improve the physical properties of the film by complementing the characteristics of polycyclohexylenedimethylene terephthalate resin through heterogeneous resin blending, and made polyethylene isosorbide cycle among various heterogeneous resins. An invention utilizing hexylenedimethylene terephthalate resin (Polyethylene Isosorbide Cyclohexylenedimethylene Terephthalate, PEICT) is presented.

Hereinafter, the implementation example will be described in more detail.

Film manufacturing method

A method of manufacturing a film according to one embodiment includes a sheet forming step of forming a composition for a film into a sheet; It includes a film forming step of obtaining a film by biaxially stretching the sheet in the machine direction and the width direction.

The film composition includes polycyclohexylenedimethylene terephthalate resin; and polyethylene isosorbide cyclohexylenedimethylene terephthalate resin. For convenience, the sum of these two resins is abbreviated as resin mixture.

Polycyclohexylenedimethylene terephthalate resin includes dicarboxylic acid-based repeating units and diol-based repeating units.

The dicarboxylic acid-based repeating unit may include a terephthalic acid-based repeating unit and may include an isophthalic acid-based repeating unit.

The diol-based repeating unit includes a repeating unit having a cyclohexane skeleton and may include a cyclohexanedimethanol residue.

The dicarboxylic acid-based repeating unit may include 80 mol% or more, 90 mol% or more, and 100 mol% or less of terephthalic acid residues, and 20 mol% or less and 15 mol% of isophthalic acid residues, based on a total of 100 mol%. Hereinafter, it may be included in 12 mol% or less, 10 mol% or less, 8 mol% or less, 6 mol% or less, and 4 mol% or less. The polyester resin may contain more than 0 mol%, more than 1 mol%, and more than 2 mol% of the isophthalic acid residue.

When the dicarboxylic acid-based repeating unit includes terephthalic acid residues and isophthalic acid residues in the above amounts, it may have relatively high melting point characteristics and low crystallization characteristics. In addition, when isophthalic acid residues are included in this amount, it can contribute to improving the long-term durability of the film.

The diol-based repeating unit may further include the following diol-based repeating units other than the cyclohexanedimethanol. Illustratively, 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-1,5-pentanediol , 2,4-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,1-dimethyl-1,5-pentanediol, and residues derived from them. .

The diol-based repeating unit may include 70 mol% or more, 80 mol% or more, 90 mol% or more, and 100 mol% or less of cyclohexanedimethanol residues, based on 100 mol% of the total.

The polyester resin may be polycyclohexylenedimethylene terephthalate resin.

The polycyclohexylenedimethylene terephthalate resin may have a weight average molecular weight (Mw) of 30,000 g/mol to 50,000 g/mol, and may be 30,000 g/mol to 40,000 g/mol.

The polycyclohexylenedimethylene terephthalate resin may have a melting point of 280°C or higher. This has a higher melting point compared to polyethylene terephthalite resin, a common polyester resin, and can provide excellent heat resistance to the film.

The polyethylene isosorbide cyclohexylenedimethylene terephthalate resin includes an isosorbide-based repeating unit, a cyclohexylenedimethylene repeating unit, and a terephthalic acid-based repeating unit.

Illustratively, the polyethylene isosorbide cyclohexylenedimethylene terephthalate resin may include a diol repeating unit and a dicarboxylic acid repeating unit.

The diol repeating unit may include an isosorbide-based repeating unit and a cyclohexylenedimethylene repeating unit, and may further include an ethylene-based repeating unit.

Based on 100 mol% of the diol repeating unit, the isosorbide-based repeating unit may be included in an amount of 1 to 40 mol%, 1 to 30 mol%, and 1 to 15 mol%. Based on 100 mol% of the diol repeating unit, the cyclohexylenedimethylene repeating unit may be included in an amount of 1 to 60 mol%, 10 to 60 mol%, and 40 to 60 mol%. Based on 100 mol% of the diol repeating unit, the ethylene-based repeating unit may not be included or may be included in the remaining amount.

It may contain 1 to 100 mol% of terephthalic acid repeating units based on 100 mol% of the dicarboxylic acid repeating units.

Polyethylene isosorbide cyclohexylenedimethylene terephthalate resin having the above-mentioned characteristics can have a beneficial effect on controlling the glass transition temperature and crystallinity of the film.

For example, the polyethylene isosorbide cyclohexylenedimethylene terephthalate resin may be a commercially available product under the trade name ECOZEN, specifically ECOZEN T90, ECOZEN T95, and ECOZEN T110 manufactured by SK Chemicals. , ECOZEN T120, etc. may be applied, but are not limited thereto.

The polyethylene isosorbide cyclohexylenedimethylene terephthalate resin may be an amorphous resin. When applying the polyethylene isosorbide cyclohexylenedimethylene terephthalate resin, which is an amorphous resin, the crystallinity of the film is more advantageous for controlling the crystallinity of the film.

The polyethylene isosorbide cyclohexylenedimethylene terephthalate resin contains a cyclohexylenedimethylene repeating unit and a terephthalic acid repeating unit in the polymer molecule, and may have excellent compatibility with the polycyclohexylenedimethylene terephthalate resin. . In addition, the polyethylene isosorbide cyclohexylenedimethylene terephthalate resin does not contain an isomeric isophthalic acid residue in the molecule, and thus can control crystallinity while substantially suppressing a decrease in melting temperature.

The film composition may include the polycyclohexylenedimethylene terephthalate resin and polyethylene isosorbide cyclohexylenedimethylene terephthalate resin in a weight ratio of 1:0.1 to 0.5. The weight ratio may be 1:0.15 to 0.45, and may be 0.15 to 0.35. The glass transition temperature that can be improved by applying polyethylene isosorbide cyclohexylenedimethylene terephthalate resin is maintained while maintaining the advantages of polycyclohexylenedimethylene terephthalate resin compared to applying a mixture of the two resins at this content. , better effects such as crystallinity control can be obtained.

The film composition may further include inorganic particles as needed. Inorganic particles may be mixed with the above resins and included in the film.

The inorganic particle is, for example, any one selected from the group consisting of silica, talc, titanium oxide (TiO ₂ ), calcium carbonate (CaCO ₃ ), barium sulfate (BaSO ₄ ), and combinations thereof. may be included.

Applying the inorganic particles can help increase the mechanical strength of the film.

The film composition may further include an antioxidant.

Antioxidants may be applied to prevent aging of the resin exposed to high temperatures during the polyester resin synthesis process, but in embodiments, they are applied during the process of filmizing the resin, not during the resin synthesis process. Additionally, three or more types of these antioxidants can be mixed and applied. Specifically, antioxidants may include phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants.

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; Benzenepropanoic 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 it may be a combination thereof.

The phosphorus-based antioxidant is exemplarily 3,9-bis(2,4-dicamylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane [3 ,9-Bis(2,4-dicumylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[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-tertiary-butylphenyl)4,4'-biphenylene diphosphonite; Or it may be 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; Lauryl stearyl-3,3'-thiodipropionic acid ester; Pentaerythrityl tetrakis (3-laurylthio propion ester); Or it may be a combination thereof.

The phenolic antioxidant may be included in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the polycyclohexylenedimethylene terephthalate resin.

The phenolic antioxidant may be included in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the resin mixture.

The phosphorus-based antioxidant may be included in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the polycyclohexylenedimethylene terephthalate resin.

The phosphorus-based antioxidant may be included in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the resin mixture.

The sulfur-based antioxidant may be included in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the polycyclohexylenedimethylene terephthalate resin.

The sulfur-based antioxidant may be included in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the resin mixture.

The sulfur-based antioxidant is applied in an amount of 30 parts by weight or more based on 100 parts by weight of the phenol-based antioxidant.

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

The phosphorus-based antioxidant and the phenol-based antioxidant may be applied at a weight ratio of 1:0.1 to 4, and may be applied at a weight ratio of 0.3 to 1.2.

The film may contain more than 800 ppm, may contain more than 1,000 ppm, may contain more than 1,200 ppm, may contain more than 1,800 ppm, and may contain more than 2,000 ppm based on 100 parts by weight of the resin mixture. It can contain more than 2,200 ppm. The antioxidant may be included at 5,000 ppm or less, and may be included at 4,000 ppm or less. When the antioxidant is applied in this range, it can contribute to improving the long-term durability of the film and provide a film that retains excellent mechanical properties for a long period of time.

In embodiments, the inventors have found that the amount of antioxidant applied to improve long-term durability can be related to the monomer content of the resin. For example, it was confirmed that when the polyester resin is a polycyclohexylenedimethylene terephthalate resin and the content of the isophthalic acid residue contained in the resin changes, there is a difference in the content of the required antioxidant.

C _IPA is the content (mol%) of the isophthalic acid residue based on the entire dicarboxylic acid repeating unit in the polycyclohexylenedimethylene terephthalate resin, and C _OA is the content of the antioxidant contained in the polyester film. When the content is expressed in ppm units (by weight), the long-term reliability index (unit: ppm/mol%) is calculated as C _OA /(C _IPA +5).

The film may have a long-term reliability index of 120 to 400 ppm/mol%, 130 to 350 ppm/mol%, and 180 to 300 ppm/mol%. If the long-term reliability index is too large, there is concern about the waste of antioxidants or changes in physical properties due to excessive use, and if the long-term reliability index is too small, long-term reliability may decrease.

Additionally, the inventors confirmed that by increasing the content of isophthalic acid residues in the polycyclohexylenedimethylene terephthalate resin, crystallinity control can be made easier. However, it was determined that applying only this method lowers the melting temperature of the resin itself, which may be an obstacle to improving heat resistance. Accordingly, the above-mentioned method called resin blending was applied, and when mixed with the polyethylene isosorbide cyclohexylenedimethylene terephthalate resin and applied as a resin mixture, the heat resistance of the film was improved through improvement of the glass transition temperature, etc. ; Beneficial effects such as improvement in film fairness and fracture resistance were also obtained through improvement in tear strength.

The film of the embodiment may further include an applicator (electrostatic applicator).

The applicator may be a salt of an alkali metal or a salt of an alkaline earth metal, and contributes to forming the extruded resin into a sheet in the film manufacturing process. Exemplarily, the licensor may be a magnesium-based compound or a potassium-based compound, and specifically, magnesium acetate, potassium acetate, or a mixture thereof may be applied.

The applicator may be applied so that the content of the metal or metal ion contained in the applicator is 300 to 1000 ppm based on 100 parts by weight of the resin mixture.

The licensor may be a mixture of magnesium acetate and potassium acetate. The mixture may include magnesium and potassium at a content ratio (molar ratio) of 1:1 to 10, and may include a content ratio (molar ratio) of 1:5 to 10. In this range, the function of the applicator is sufficiently performed while interaction with other additives is substantially suppressed, thereby providing a film with improved durability.

The sheet forming step can be applied without limitation as long as it is a method of forming the resin into a sheet.

Illustratively, the sheeting step may include an extrusion process of extruding the film composition at an extrusion temperature.

The extrusion temperature applied in the extrusion process may be 250 ℃ to 300 ℃, and may be 280 ℃ to 300 ℃. The pressure applied to the extruder at the above temperature allows extrusion to proceed appropriately.

The film forming step is a step of obtaining a film by biaxially stretching the sheet in the machine direction and the width direction.

The film forming step may include a machine direction stretching process of stretching the sheet in the machine direction at a first stretching temperature and a first stretching ratio.

The film forming step may include a width direction stretching process to obtain a stretched sheet by stretching the sheet in the width direction at a second stretching temperature and a second stretching ratio.

The first stretching temperature may be 80°C to 100°C, 85°C to 100°C, and 90°C to 100°C.

The first stretching ratio may be 3.0 to 3.5, and may be 3.1 to 3.4.

The second stretching temperature may be 200°C to 240°C, 210°C to 240°C, or 220°C to 240°C.

The second stretching ratio may be 3.5 to 3.9, 3.6 to 3.9, or 3.7 to 3.9.

By applying the first stretching temperature and the second stretching temperature, stretching can be performed while substantially reducing the occurrence of breakage during the process.

By applying the first draw ratio and the second draw ratio, it is possible to provide a film with improved tear strength, etc.

A heat setting process of heat setting the stretched sheet to obtain the film may be further included. Heat setting can be performed at a temperature of 200 to 250°C.

The film manufacturing method of the embodiment can produce a film with excellent crystallinity control, heat resistance, and mechanical strength by blending two resins. A detailed description of the film will be provided later.

film

Films according to embodiments include polycyclohexylenedimethylene terephthalate resin; and polyethylene isosorbide cyclohexylenedimethylene terephthalate resin.

The film may further include the characteristics of each of the two resins mentioned in the film composition, their application ratios, antioxidants, inorganic particles, applicators, etc. in their own form or in the form of their decomposition products. Since more specific descriptions overlap with those described above, detailed descriptions are omitted.

The film may have a glass transition temperature of 93°C or higher, 94°C or higher, 95°C or higher, and 96°C or higher. The glass transition temperature of the film may be 100°C or lower and 98°C or lower. This glass transition temperature is about 3 to 5°C higher than a film using the same polycyclohexylenedimethylene terephthalate resin as the entire amount of the resin, and is determined while substantially suppressing the decrease in melt temperature. It is advantageous in controlling sex.

The film of the embodiment has a longitudinal tear strength of 270 N/mm or more.

The longitudinal tear strength of the film may be 275 N/mm or more, may be 280 N/mm or more, may be 285 N/mm or more, may be 290 N/mm or more, may be 300 N/mm or more, and may be 310 N/mm or more. It may be more than N/mm. The longitudinal tear strength may be 350 N/mm or less, and may be 340 N/mm or less. This longitudinal tear strength is significantly improved compared to the case where the resin blend is not applied, and can help prevent fracture substantially despite the tension applied to the film during the process.

The film of the embodiment may have a tear strength in the width direction of 300 N/mm or more.

The tear strength in the width direction of the film may be 305 N/mm or more, 315 N/mm or more, 320 N/mm or more, 325 N/mm or more, 330 N/mm or more, 335 It may be more than N/mm. The tear strength in the width direction may be 360 N/mm or less, and may be 350 N/mm or less. This tear strength in the width direction is significantly improved compared to the case where the resin blend is not applied, and can help prevent fracture substantially despite the tension applied to the film during the process or during the stamping process that can be applied later. .

The film of the embodiment may have a difference between the longitudinal tear strength and the width direction tear strength of 70 N/mm or less, 60 N/mm or less, 52 N/mm or less, 45 N/mm or less, and 30 It may be less than N/mm. These comparatively different films can substantially reduce the occurrence of breakage and provide films with excellent processability.

The film of the embodiment may be a biaxially oriented polyester film.

The film of the embodiment may be a sequentially biaxially oriented polyester film.

Films of embodiments may have a thickness of less than 1,000 μm, less than 800 μm, less than 600 μm, less than 500 μm, less than 300 μm, less than 100 μm, less than 80 μm, less than 70 μm, less than 60 μm, or less than 50 μm. The film may have a thickness of 1 ㎛ or more, 2 ㎛ or more, 5 ㎛ or more, or 10 ㎛ or more.

The film can have excellent shrinkage under hot air conditions where hot air at a temperature of 150°C is applied and left for 30 minutes. For example, the shrinkage rate of the film may be 1.2% or less.

The shrinkage rate can be calculated as follows.

[Equation 1]

Shrinkage rate (%) = {(original length - length after shrinkage)/(original length)}Х100%

The film of the embodiment improves mechanical strength through a process such as stretching,

By applying various technical means, such as controlling the blending of the resin, crystallinity can be controlled and, in particular, the possibility of crystallization and transverse fracture at the ends of the film can be reduced.

The film of the embodiment is good for application to fuel cells, and is particularly excellent for use as a sub-gasket film included in the stack structure of a hydrogen fuel cell.

The film of the embodiment is suitable for application to an antenna.

The film of this embodiment utilizes heat resistance and insulation properties, making it excellent for use in applications such as surface coatings for electrical appliances and interior materials for electric vehicles.

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.

Preparation of homo PCT film (Comparative Example 1)

A monomer mixture containing 100 mol% of cyclohexanedimethanol (CHDM) as a diol-based compound and 96 mol% of terephthalic acid (TPA) and 4 mol% of isophthalic acid (IPA) as a dicarboxylic acid-based compound was added to a stirrer. After adding 1 ppm of titanium catalyst based on 100 parts by weight of the mixture, a transesterification reaction was performed at 275°C.

The transesterified material was transferred to a separate reactor equipped with vacuum equipment, and then polymerized at 285°C for 160 minutes to obtain polycyclohexylenedimethylene terephthalate (PCT) resin.

The PCT resin (abbreviated as PCT4) was processed into a masterbatch chip and dried at a temperature of 140°C. As an antioxidant, BASF's IRGANOX 1010, IRGAFOS 168, and ADEKA's ADK STAB AO-412S were mixed in equal amounts by weight and applied at about 2000 ppm (based on the entire resin, by weight). In the case of the additive, magnesium and potassium were 9. Magnesium acetate and potassium acetate were mixed and applied to achieve a weight ratio of :1. Afterwards, the raw materials were put into an extruder, extruded into a sheet form at a temperature of about 295°C, and casted on a casting roll.

The extruded sheet was preheated at a temperature of 85°C for 10 seconds and then stretched 3.0 times in the machine direction (MD) at a temperature of 95°C. Next, it was stretched 3.7 times in the width direction (TD) at a temperature of 230°C. Afterwards, the stretched sheet was heat-set at a temperature of 230°C for about 30 seconds and relaxed to prepare a 25 ㎛ thick homo PCT film.

Preparation of blended PCT film (Examples 1 to 4)

It was manufactured in the same manner as the above homo-PCT film, but the applied resin was a mixture of PCT resin and ECOZEN resin (PEICT resin). Differences from the manufacturing of homo PCT film, such as mixing ratio and stretching ratio, are shown in Table 1 below.

Evaluation of physical properties

(Measurement of glass transition temperature)

The glass transition temperature of the film for each example and comparative example was measured. Specifically, a 3 mg to 6 mg film sample was placed in TA's Q2000 model, a differential scanning calorimeter, and then a first scan was performed by applying a first scan temperature increase rate of 10°C/min. After quenching the sample, a second scan was performed under the same conditions as the first scan to measure the glass transition temperature, and the results are shown in Table 1 below.

(Measurement of tear strength)

The tear strength was determined by inserting a specimen cut to the standard according to ASTM D1004 between 25.4 mm (1 in) intervals of the tear test device and fixing it with a clip. It was set to pull up and down to fracture at a speed of 100 mm/min, and the measurement results are shown in Table 1 below, divided into the width direction and the machine direction.

(Measurement of shrinkage rate)

The films were cut into sizes of 15 mm in width and 300 mm in length, respectively, to produce specimens. The specimen was placed in an oven at 150°C for 30 minutes, taken out of the oven, and the longitudinal length of the specimen was measured under a microscope. From the measured values, the shrinkage rate value was calculated according to Equation 1 below, and if the shrinkage rate value is less than 1.2%, it is Pass, and if it is more than 1.2%, it is Fail, which is indicated in Table 1 below.

[Equation 1]

Shrinkage rate (%) = [(L ₀ - L)/L ₀ ] * 100

In Equation 1, L ₀ is the length before heat treatment, and L is the length after heat treatment.

PCT+ECOZEN(PEICT) total standard content stretching ratio
(MD/TD) LSM/TSM temperature (℃) Shrinkage rate (%) Comparative Example 1 - 3.0x3.7 95/230 Pass Example 1 15% by weight* 3.2x3.7 Pass Example 2 3.2x3.9 Pass Example 3 20% weight%** 3.4x3.7 Pass Example 4 3.4x3.9 Pass Tg (℃) machine direction
Tear strength (N/mm) Width direction
Tear strength (N/mm) Tear strength difference (N/mm) Comparative Example 1 91.03 192.37 296.84 104.47 Example 1 95.7 280.28 331.24 50.96 Example 2 281.55 307.34 25.79 Example 3 96.15 301.71 343.09 41.38 Example 4 323.78 337.61 13.83

* The PEICT content ratio based on 1 part by weight of PCT resin is 0.18.

** PEICT content ratio based on 1 part by weight of PCT resin is 0.25.

Referring to Table 1, it can be seen that the samples to which the film composition of the embodiment was applied had improved tear strength, had a low difference in tear strength, and maintained the excellent physical properties of homo resin, such as shrinkage rate.

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 made by those skilled in the art using the basic concept of the present invention defined in the following claims are also possible. falls within the scope of rights.

Claims (10)

A sheet forming step of forming the film composition into a sheet;
It includes a film forming step of obtaining a film by biaxially stretching the sheet in the machine direction and the width direction,
The film composition includes polycyclohexylenedimethylene terephthalate resin; and polyethylene isosorbide cyclohexylenedimethylene terephthalate resin;
A method of producing a film, wherein the longitudinal tear strength of the film is 270 N/mm or more.
According to paragraph 1,
The composition for the film includes the polycyclohexylenedimethylene terephthalate resin and the polyethylene isosorbide cyclohexylenedimethylene terephthalate resin in a weight ratio of 1:0.1 to 0.5.
The method of claim 1, wherein the film forming step is
A machine direction stretching process of stretching the sheet in the machine direction at a first stretching temperature and a first stretching ratio; and
A width direction stretching process of obtaining a stretched sheet by stretching the sheet in the width direction at a second stretching temperature and a second stretching ratio; Including,
The first stretching temperature is 80°C to 100°C, the first stretching ratio is 3.0 to 3.5, the second stretching temperature is 200°C to 240°C, and the second stretching ratio is 3.5 to 3.9. .
According to paragraph 1,
The sheeting step includes an extrusion process of extruding the film composition at an extrusion temperature,
A method of producing a film wherein the extrusion temperature is 250 ℃ to 300 ℃.
polycyclohexylenedimethylene terephthalate resin; and polyethylene isosorbide cyclohexylenedimethylene terephthalate resin;
A film having a longitudinal tear strength of at least 270 N/mm.
According to clause 5,
A film having a glass transition temperature of 93°C or higher.
According to clause 5,
A film wherein the ratio of the polycyclohexylenedimethylene terephthalate resin and the polyethylene isosorbide cyclohexylenedimethylene terephthalate resin is 1:0.1 to 0.5.
According to clause 5,
A film having a tear strength in the width direction of 300 N/mm or more.
According to clause 5,
A film in which the difference between longitudinal tear strength and width direction tear strength is 70 N/mm or less.
According to clause 5,
The polycyclohexylenedimethylene terephthalate resin includes a diol-based repeating unit and a dicarboxylic acid-based repeating unit,
A film comprising 0 to 20 wt% of isophthalic acid residues, based on 100 wt% of the total carboxylic acid residues.