KR20200068903A - Polyester resin composition, polyester film, and preparation method thereof - Google Patents

Abstract

A manufacturing method of a polyester film of the present invention is a method to which a lubricant having a low melting point or softening point is applied, enabling efficient manufacturing of polyester films having excellent calendering properties and excellent optical properties.

Description

Polyester resin composition, polyester film and manufacturing method thereof {POLYESTER RESIN COMPOSITION, POLYESTER FILM, AND PREPARATION METHOD THEREOF}

The present invention relates to a polyester resin composition, a polyester film and a method for manufacturing the same.

The calendering process is a process of forming films and sheets using a calender, that is, a rolling machine in which several heating rolls are arranged. The calendering process has been mainly used to make films and sheets because the production speed is faster than the extrusion process and it is easy to process with a thin thickness.

Polyvinyl chloride (PVC) resins, which have been mainly used in the calender process, have excellent processability, but are difficult to recycle and cause environmental problems when discarded. In addition, polypropylene (PP) resin has excellent calenderability, but is not environmentally friendly, and has a problem of printing and lamination without corona and primer treatment.

On the other hand, polyethylene terephthalate (PET) resin, which is a typical polyester resin, has excellent properties for price, but has poor calenderability. Accordingly, it is known to manufacture a polyester film using a polyethylene terephthalate (PETG) resin modified with glycol to have properties suitable for being applied to a calendering process.

Domestic Patent Publication No. 2014-0109506 Domestic Patent Publication No. 2016-0180844

An object of the present invention is to provide a calendering polyester resin composition, a polyester film, a method for manufacturing the same, and the like, which have little staining on the surface and have excellent light transmittance.

In one aspect for achieving the above object, the present invention is a calendering polyester resin composition comprising 0.1 to 10 parts by weight of a lubricant based on 100 parts by weight of a polyester resin containing a dicarboxylic acid repeating unit and a diol repeating unit. Preparation steps to prepare; A kneading step of kneading the calendering polyester resin composition in a blender to prepare a kneading composition; The kneading composition is introduced into a calender roll comprising two or more rollers rotating and rolling in opposite directions to each other, and the kneading compositions are rolled through a predetermined position between the calender rolls and formed into a sheet shape to form a polyester film. Rolling step for manufacturing; And it provides a method of manufacturing a polyester film comprising; a completion step of manufacturing a calendaring polyester film including a cooling process for cooling the polyester film.

The lubricant may include a first lubricant having a melting point or a softening point of 100°C or less.

The above manufacturing method can produce a polyester film having a stain pattern area of 30% or less.

The lubricant may further include a second lubricant having a melting point or a softening point of more than 100°C and 160°C or less.

In the rolling step, the roll speed of the calender roll may be applied to 15 m/min or more.

The lubricant may further include a second lubricant.

The melting point or softening point of the second lubricant may be at least 10 °C different from the melting point or softening point of the first lubricant.

The lubricant may further include two or more first lubricants.

The first lubricant of the two types may have a difference in melting point or softening point of 10°C or more.

The polyester resin may include 20 to 90 mol% of an aliphatic or alicyclic diol repeating unit based on the entire diol compound constituting the polymer chain of the polyester resin.

The diol repeating unit may be derived from a compound having a repeating unit having a diol residue in a linear or branched form having 2 to 10 carbon atoms.

The diol repeating unit may include a neopentyl glycol repeating unit.

The polyester film may have a haze value of 15% or less.

The polyester film may have a total transmittance of 80% or more.

In another aspect for achieving the above object, the present invention comprises 0.1 to 10 parts by weight of a lubricant based on 100 parts by weight of a polyester resin comprising a dicarboxylic acid repeating unit and a diol repeating unit, and the lubricant melts A calendered polyester film comprising a first lubricant having a point or softening point of 100° C. or less, and having a speckle area observed on one surface of 30% or less is provided.

The lubricant may further include a second lubricant.

The melting point or softening point of the second lubricant may be at least 10 °C different from the melting point or softening point of the first lubricant.

The polyester film may have a total transmittance of 80% or more.

The polyester resin may include 20 to 90 mol% of an aliphatic or alicyclic diol repeating unit based on the entire diol compound constituting the polymer chain of the polyester resin.

In another aspect for achieving the above object, the present invention comprises 0.1 to 10 parts by weight of a lubricant based on 100 parts by weight of a polyester resin comprising a dicarboxylic acid repeating unit and a diol repeating unit, and the lubricant A calendering polyester resin composition comprising a first lubricant having a melting point or softening point of 100° C. or less is provided.

The first lubricant may have a viscosity (Viscosity) measured at 120 °C of 20 mPa.s or less.

The lubricant may further include a second lubricant.

The melting point or softening point of the second lubricant may be at least 10 °C different from the melting point or softening point of the first lubricant.

The lubricant may further include a second lubricant having a melting point or a softening point of more than 100°C and 160°C or less.

The polyester resin contains 20 to 90 mol% of any one repeating unit selected from the group consisting of a neopentyl glycol repeating unit, a cyclohexanedimethanol repeating unit, and combinations thereof as a diol repeating unit. can do.

The calendering polyester resin composition of the present invention, a polyester film, and a method for manufacturing the same, are prepared by effectively applying a calendering method to produce a polyester film, while producing a polyester film having substantially no or little mottled occurrence and excellent light transmittance. can do. The present invention can be manufactured to have excellent physical properties while producing an environmentally friendly polyester film, which is recyclable, in an efficient calendering method.

1 is a conceptual diagram briefly illustrating a film manufacturing apparatus to which an embodiment of the present invention is applicable.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily practice. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. The same reference numerals are used for similar parts throughout the specification.

In this specification, when it is said that a configuration "includes" another configuration, this means that unless otherwise stated, other configurations may be excluded and other configurations may be further included.

In this specification, when a configuration is said to be "connected" to another configuration, this includes not only a case of'directly connecting', but also a case of'connecting another configuration in between'.

In the present specification, the meaning that B is located on A means that B is directly in contact with A, or that B is located on A while another layer is positioned between them, and B is placed in contact with the surface of A. It is not limited to being interpreted.

In this specification, the term "combination of these" included in the expression of the marki form means one or more mixtures or combinations selected from the group consisting of the elements described in the expression of the marki form, the components It means to include one or more selected from the group consisting of.

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

In 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 the present specification, a singular expression is interpreted to include a singular or plural number that is interpreted in context unless otherwise specified.

When the inventors of the present invention produce a polyester film by a calendering method, they recognize that the optical properties (transparency, haze value, etc.) of the film are deteriorated or a problem that a mottled pattern is generated on the surface may occur, and this is solved. While searching for a method to control the type of lubricant applied to the polyester resin composition for calendering, the content of the lubricant is adjusted to produce a polyester film having a relatively high light transmittance without problems such as generation of air bubbles or surface unevenness of the film. The present invention was completed after confirming that it can be manufactured with excellent production efficiency by applying a calendaring method.

Hereinafter, the present invention will be described in more detail with reference to the conceptual diagram of the film production apparatus of FIG. 1. In order to achieve the above object, a method of manufacturing a polyester film according to an embodiment of the present invention includes a preparatory step, a kneading step, a rolling step, and a completion step. ).

The preparatory step is a step of preparing a calendering polyester resin composition (1a) containing 0.1 to 10 parts by weight of a lubricant based on 100 parts by weight of a polyester resin containing a dicarboxylic acid repeating unit and a diol repeating unit.

The calendering polyester resin composition (1a) may include a lubricant in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the polyester resin, and may include 0.5 to 6 parts by weight. When the lubricant is applied in a range of such a content, it is possible to provide a polyester resin composition suitable for application in a calendering process.

The lubricant is advantageous in that it is desirable to obtain desired properties while applying one type of lubricant alone, but it is advantageous in that two or more types of lubricant can be applied to the composition to more easily secure the intended properties.

The calendering process includes forming a sheet or film while passing the resin between at least two rolling rolls. In this calendering process, if the lubricant does not sufficiently move to the resin surface, external activity is insufficient, so that the resin can be easily released from the roll, and film production itself may be difficult. In addition, if the lubricant moves too much to the resin surface, film production is possible, but rather the optical properties of the film may deteriorate. In the present invention, considering these characteristics, two or more types of lubricants are applied to the composition to obtain relatively better physical properties.

Specifically, the lubricant may include a first lubricant, and the first lubricant is a lubricant having a melting point or a softening point of 100°C or less. Specifically, the first lubricant may include one or two or more first or second lubricants having a melting point or softening point of 85° C. or less, and a first or second lubricant having a melting point or softening point of more than 85° C., respectively. The releasability and bank characteristics, which are difficult to improve at the same time, can be further improved.

The first lubricant may include a 1-a lubricant having a melting point or softening point of 75°C or less and a 1-b lubricant having a melting point or softening point of more than 75°C. When two or more first lubricants having different melting points or softening points are mixed and applied in this way, releasability and transparency that are difficult to improve at the same time can be further improved.

The lubricant may include a compound such as a fatty acid and/or a polymer material such as polyethylene. Compounds such as fatty acids and metal salts of fatty acids have a melting point or a freezing point called titer. However, in the case of a polymer material in which the classification of solid liquid gas is not clear, the melting point is not clear, and instead, the softening point is applied as a measure of the temperature at which the lubricant melts (softens), similar to the melting point. Therefore, in the present invention, the term "melting point or softening point" is used as a term for softening and melting point. However, in the present specification, even if expressed as “melting point” or “softening point” according to the context, this expression is interpreted to mean “melting point or softening point” suitable for the type of the target lubricant.

When the lubricant is applied as the first lubricant having a relatively low melting point (or softening point), the mottled phenomenon formed on the surface of the produced film can be further reduced. This is because the first lubricant has a relatively low melting point (or softening point), which is softened relatively first in the film production process, and helps to remove the bubbles of the calendering polyester resin composition from the calender bank, while at the same time the excess lubricant on the calender roll is filmed. It is thought to be because it serves to help not to remain on the surface.

The first lubricant may have a viscosity (Viscosity) measured at 120 °C of 20 mPa.s or less. This means that the first lubricant has a relatively low viscosity in a calendaring environment, and the first lubricant can impart sufficient plasticity and release properties to the composition from a relatively low temperature. When the polyester resin composition for calendering having excellent bank characteristics is applied, a calendering sheet or film having good air quality in the bank and superior surface quality can be manufactured. In addition, the first lubricant is thought to play a role in further improving the surface properties of the film by interacting with the above properties and the excess slip agent that may cause staining to be applied to the calender roll.

The lubricant may further include a second lubricant.

The melting point (or softening point) of the second lubricant may be at least 10°C different from the melting point (or softening point) of the first lubricant. When two or more lubricants having different melting points are applied together to the calendering polyester composition, the lubricant is softened at different temperatures depending on the process temperature controlled in the process of manufacturing the film by the calendering method, and some of the lubricants are softened. As a process such as disappearing, the composition may have an appropriate viscosity in a kneading process, a rolling step, or the like.

Here, the difference between the melting point or the softening point of the first lubricant and the second lubricant is when the melting point (or softening point) of the first lubricant is higher than that of the second lubricant and the first lubricant is higher than that of the second lubricant according to the calendering process. It includes all cases where the melting point (or softening point) is lower, but preferably refers to a case where the melting point (or softening point) of the second lubricant is higher than that of the first lubricant.

The second lubricant may have a melting point or a softening point of greater than 100°C, and may be greater than 100°C and less than 160°C. Specifically, the second lubricant may have a melting point or a softening point of more than 100°C and 140°C or less, and more than 100°C and 120°C or less. When the lubricant having such a melting point or softening point is applied as the second lubricant, the elution rate of the lubricant or the degree of softening of the composition can be precisely controlled during the calendering process, and the compatibility of the resin with the first lubricant can be seen. A polyester film that can be improved, and has excellent bank characteristics, optical characteristics, and surface characteristics, can be produced by a calendering method.

The second lubricant may have a viscosity (Viscosity) measured at 140 °C of 150 mPa.s or more, 150 to 1200 mPa.s, 150 to 800 mPa.s, and 150 to 550 mPa.s. Can be. This means that the second lubricant has a relatively high viscosity in a calendering environment. If the first lubricant imparts sufficient plasticity and releasability to the composition from a relatively low temperature, the second lubricant has a calendering temperature. It contributes to improving the degree of softening of the resin composition and compatibility between the first lubricant and the second lubricant. In addition, the composition comprising the second resin having such properties can help the calendering process to be operated more efficiently by helping the resin with a suitable degree of softening and the introduction of a surplus slip agent into the polymer resin. Better films can be produced.

The lubricant may include the first lubricant and the second lubricant in a weight ratio of 1: 0.1 to 2, may include a weight ratio of 1: 0.2 to 1.6, and may include a weight ratio of 1: 0.8 to 1.5. have. When the first lubricant and the second lubricant are mixed and applied to the composition in this weight ratio, a polyester film having excellent releasability, productivity, etc., and excellent optical properties can be produced.

The lubricant includes a polar lubricant containing a polar functional group in the molecule, and a non-polar lubricant having a non-polarity as a whole because the polar functional group is not contained in the molecule or the polar functional group is hardly exposed to the surface of the active body.

Specifically, the polar lubricant may be one having a functional group selected from the group consisting of hydroxyl groups, carboxyl groups, ester groups, and combinations thereof in the molecule. A polar lubricant may be applied as the first lubricant, and more specifically, the first lubricant may include at least one of a hydroxyl group, a carboxyl group, and a ster group in a molecule to include a polar portion in the same molecule, and the polar portion And a non-polar part containing an alkyl or alkenyl group having 12 or more carbon atoms. Specifically, the first lubricant may include one or more functional groups selected from the group consisting of hydroxyl groups, carboxyl groups, ester groups, and combinations thereof in the molecule, and may have 12 to 66 carbon atoms.

When a lubricant having this property is applied as a first lubricant, the properties between the polyester resin having a polar part and a non-polar part are similar so that the space between the polymer chains is opened and the lubricant is mixed to help soften the polymer resin. , It also improves the compatibility with other lubricants and helps the composition to be kneaded more easily.

The lubricant is i) a fatty acid-based lubricant comprising a fatty acid-based lubricant that is a fatty acid, a fatty acid salt, and an ester of fatty acids, and ii) a polymer-based lubricant comprising polyethylene, low-density polyethylene, ultra-low-density polyethylene, polyethylene oxide, or low-density polyethylene oxide. It may include any one or more selected from the group consisting of phosphorus polyethylene-based lubricant.

The polyester resin includes a dicarboxylic acid compound and a diol compound as monomers. That is, the polyester resin may have a repeating unit derived from a dicarboxylic acid compound and a diol compound polymerized therefrom.

The polyester resin may be a diol compound based on 1 mol of the dicarboxylic acid compound in a ratio of 1.05 to 3 mol to be polymerized. When blended in the above ratio, the esterification reaction proceeds stably, which is advantageous to form a sufficient ester oligomer.

The dicarboxylic acid compound is terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, cyclohexane dicarboxylic acid, succinic acid, glutaric acid, orthotalic acid, adipic acid, azelaic acid, sebacic acid, decandicarboxylic acid , 2,5-furandicarboxylic acid, 2,5-thiofendicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4'-bibenzoic acid, and any one selected from the group consisting of can do. Specifically, the dicarboxylic acid compound may be any one selected from the group consisting of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, cyclohexanedicarboxylic acid, and combinations thereof.

The diol compound may include a linear or branched aliphatic diol, alicyclic diol, aromatic diol. Specifically, the linear or branched aliphatic diol is ethylene glycol, diethylene glycol, neopentyl glycol, 1,3-propanediol, 1,2-octanediol, 1,3-octanediol, 2,3-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 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, 1,6-hexanediol, 2-ethyl-3-methyl -1,5-hexanediol, 2-ethyl-3-ethyl-1,5-hexanediol, 1,7-heptanediol, 2-ethyl-3-methyl-1,5-heptanediol, 2-ethyl-3 It may be any one selected from the group consisting of -ethyl-1,6-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol and combinations thereof.

Specifically, the alicyclic diol may include any one selected from the group consisting of cyclohexanedimethanol, isosorbide, 2,2,4,4-tetramethyl-1,3-cyclobutanediol and combinations thereof.

When a film or sheet is produced by calendering the polyester resin containing the alicyclic diol, chemical structurally strong bonds can be obtained, thereby making a polyester film having improved impact strength and heat resistance. In addition, when a film or sheet is prepared by calendering using the composition containing the linear or branched aliphatic diol, the packing is well made to produce a polyester film having improved chemical resistance and surface strength of the film or sheet. Can be.

Specifically, the diol component may include any one glycol component selected from the group consisting of ethylene glycol, diethylene glycol, neopentyl glycol, cyclohexanedimethanol, and combinations thereof. More specifically, the diol-based compound may include neopentyl glycol as the glycol component.

The diol-based compound, based on the total of the diol-based compound, may include neopentyl glycol in 20 to 90 mol%, 30 to 80 mol% of neopentyl glycol, and 30 to 60 mol% of Neopentyl glycol. When neopentyl glycol is included in the diol-based compound in this range, the intrinsic viscosity of the resin is set to an appropriate range to further improve the calendering processability, and further improve the color and mechanical properties of the produced film. Can be.

When the lubricant described above is applied to a polyester resin containing 20 to 90 mol% of the diol component described above, specifically 30 to 80 mol%, and more specifically 30 to 60 mol% as an aliphatic diol, better calenderability is achieved. Can be obtained.

Specifically, in the calendering process, the lubricant interacts with the polyester resin to prevent releasing and sticking well to the calendering roll, bank characteristics such as being well mixed in the calender bank, and bubbles are well removed, and transparency to the prepared sheet. All criteria such as transparency to control the degree of clouding must be satisfied at a certain level or higher.

In order for the polyester resin composition to satisfy all of the properties required for the calendering process to a certain level or higher, the lubricant must quickly form a lubricant film on the surface of the polyester resin in the calendering process to have sufficient release property with the calender roll. . However, when the movement of the lubricant to the resin surface is excessively excessive, a phenomenon that the sheet or film produced by the calendering process becomes cloudy may appear, which may adversely affect optical properties. Therefore, in the calendering process, the lubricant film should be formed quickly on the resin surface, and at the same time, the space between the polymer chains in the polyester resin should be opened so that the lubricant does not move to the surface so that the lubricant is properly dispersed between the resins. The polyester resin is softened appropriately so that bubbles may be removed from the bank or the like.

The polyester resin is influenced by the linear chain structure forming the aliphatic diol component of the polyester, and the lubricants are more easily introduced into the polyester resin in comparison to the case of having a bulky chain structure such as aromatic. It can be, and it is considered that it is possible to open the space between the polymer chains in a short time, so that it can have better calenderability.

In addition, when the first lubricant and the second lubricant are applied together with one or more, respectively, a total of two or more, the calendering properties of the polyester resin of the present invention and the physical properties of the film may be further improved. It is evaluated that the polyester resin composition of the present invention having such properties has excellent properties in terms of releasability, bank properties, roll speed, and mottled area.

This is a property that the lubricants having different melting points (or softening points) have the properties of the lubricant (the first lubricant) itself, and after securing the releasability required in the calendering process in the resin, they are distinguished from the lubricant (the first lubricant). Interaction with other lubricants (second lubricants) having a melting point (or softening point) allows the surplus lubricant to move more easily into the resin, and at this time, the polyester resin component comprising a repeating unit derived from the aliphatic diol and It interacts to make it easier to proceed with these lubricants.

In addition to the polyester resin and the lubricant, the polyester resin composition may further include components such as a polymerization catalyst, a stabilizer, and a colorant.

These polymerization catalysts, stabilizers and colorants can be added to the product of the esterification reaction or transesterification reaction prior to the initiation of the polymerization reaction, and added to the mixed slurry comprising dicarboxylic acid and diol compound before the esterification reaction. It may be added in the middle of the esterification reaction step.

As the polymerization catalyst, an antimony-based compound, a titanium-based compound, a germanium-based compound, an aluminum-based compound, or a mixture of these compounds may be used. Antimony trioxide, antimony acetate, and antimony glycolate may be used as the antimony-based compound. As the titanium-based compound, tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, titanium dioxide, and titanium dioxide /Silicone dioxide copolymer may be used, and germanium-based compounds may include germanium dioxide, germanium acetate, and germanium glycolate.

As the stabilizer, phosphorus-based compounds such as phosphoric acid, trimethyl phosphate, and triethyl phosphate may be used, and the amount of addition may be 10 to 100 ppm based on the weight of the final polymer based on the phosphorus (P) mass.

The colorant is added to improve the color of the polymer, and a cobalt acetate, cobalt propionate metal salt colorant, and a colorant that is a dye component may be used, and the amount added may be 0 to 100 ppm based on the weight of the final polymer. .

The intrinsic viscosity (IV) of the polyester resin may be 0.6 to 3.0 dl/g. Specifically, the intrinsic viscosity (IV) of the polyester resin is 0.6 to 2.5 dl/g, 0.6 to 2.0 dl/g, 0.6 to 1.5 dl/g, 0.6 to 1.0 dl/g, 0.62 to 1.5 dl/g, 0.64 To 1.2 dl/g or 0.66 to 0.85 dl/g. When the intrinsic viscosity of the polyester resin is in the above range, it is possible to produce a polyester film having excellent calendering properties and excellent thickness uniformity of sheets and films.

The calendering polyester resin composition 1a prepared through the preparation step is then administered to the film production apparatus 10 from the kneading step.

The kneading step includes a kneading process of kneading the calendering polyester resin composition in a blender 100 to prepare a kneading composition.

Specifically, the kneading process may be performed by applying a high speed mixer (eg, Henshell Mixer). More specifically, the kneading process may be performed by pelletizing the polyester resin composition and mixing the pelletized polyester resin in a high-speed mixer for 30 to 300 seconds at a temperature of 20 to 40°C. have.

The kneading step may include the kneading process and gelling process described above.

The gelling process is a process of kneading and gelling the composition, i) a process of gelling using a streamlined extruder or a semi-variable intensive mixer, ii) a process of homogenizing using a mixing roll, or iii) homogenizing using a warming roll The process may include at least one process selected from among processes, or may be performed by sequentially applying the above three processes.

The gelled calendering polyester resin composition is moved as a kneading composition to be applied to a rolling step proceeding in a calendering method. At this time, the calendering polyester resin composition 1a may be moved to the calender roll 200 by the transport unit 120.

In the rolling step, the kneading composition is introduced into the calender roll 200 including two or more rollers that rotate and roll in opposite directions, so that the kneading compositions pass through a predetermined position between the calender rolls 200. It is a step of producing a polyester film (1b) is molded into a sheet shape.

In the rolling step, a polyester film is molded by a calendering method using a plurality of calender rolls 200. In FIG. 1, the calendar rolls 200 are shown as four, but the number and arrangement form can be changed.

In the rolling step, the temperature of the calender roll 200 may be applied to 110 to 230°C, and a temperature of 145 to 210°C may be applied. When the rolling step proceeds under these temperature conditions, it is possible to produce a more efficient polyester film.

In addition, the roll speed of the calender roll 200 may be applied to 15 m/min or more. When the lubricant having the above properties is applied, the calendering roll speed is applied at 15 m/min or more, while satisfactory releasability, bank characteristics, etc., which can produce a film with excellent production efficiency and high quality at the same time It means a point.

The polyester resin includes a repeating unit having a diol residue in a linear or branched form having 2 to 10 carbon atoms as the diol repeating unit. Specifically, the polyester resin may include a repeating unit of a diol compound having a linear or branched diol residue having 2 to 10 carbon atoms as the diol repeating unit, and may include a repeating unit of neopentyl glycol as the diol repeating unit. have.

The characteristics of these polyester resins are non-polar functional groups on the surface of the polyester film and polar functional groups on the central portion in the kneading and rolling processes described below, and interact with the lubricant described above. Specifically, the polyester resin having such a diol repeating unit can more easily enter the lubricant into the resin due to the interaction with the lubricant described above in the calendering process, that is, the linear chain structure formed by the aliphatic diol component. There is, it can improve the roll speed, bank characteristics, etc., through which it is possible to produce a calendaring polyester film excellent in both surface properties and optical properties.

In the rolling step, the polyester film 1b is manufactured by peeling the polyester film from the calender roll 200 using take off rolls (not shown) and adjusting the thickness and smoothness of the polyester film. It may further include an off process. This off-process may be performed at a temperature of 120 to 170°C.

The rolling step may further include an embossing step if necessary, and the embossing step is a step of forming an embossed pattern on the polyester film 1b using an embossing roll or the like. The embossing step may be performed at a temperature of 30 to 130 ℃ by applying an embossing roll (not shown). The polyester film 1b having an embossed pattern formed on the surface through such an empo treatment step may have better winding properties.

The completion step includes a cooling process for cooling the polyester film 1b.

The completion step may include a cooling process for cooling the polyester film produced in the rolling step, a cutting process for cutting the cooled polyester film, and a winding step for winding the cut film.

The cooling process may be performed through a cooler 300 and the winding step may be performed through a winder 400.

In the cooling process, the polyester film 1b may be cooled using a cooling roll (not shown), and the temperature of the cooling roll may be maintained at -5°C to 50°C.

The polyester film 1b may be wound after cutting the width of the film using a side trimming device and measuring the thickness of the produced film using a thickness gauge.

The polyester film 1b thus produced has particularly excellent optical properties with excellent processability.

The polyester film (1b) may have a mottled area of 30% or less, and may be 20% or less. The polyester film (1b) may have a mottled area of 10% or less, and may be 0.001 to 10%. The calendered polyester film having a small uneven surface area can be efficiently manufactured through a calendering process, and has excellent optical characteristics at the same time. Specifically, it is thought that the uneven pattern observed on the surface of the polyester film produced by the calendering method is generated by the effect of the lubricant. However, when it is desired to manufacture a polyester film by an efficient calendering method, and in order to improve process efficiency, the use of a lubricant is essential. In the present invention, by applying the lubricant described above, it is possible to produce a polyester film with high efficiency while reducing the area of the occurrence of the mottled pattern formed on the surface of the polyester film.

The polyester film 1b may have a haze value of 15% or less, 13% or less, 11% or less, and 0.001 to 9%.

The polyester film 1b may have a total light transmittance of 80% or more and 88% or more.

The above-described polyester film having a haze value and transmittance as described above means that a film having fairly excellent optical properties can be efficiently produced by a calendering method.

The calendering polyester film 1b according to another embodiment of the present invention contains 0.1 to 10 parts by weight of a lubricant, based on 100 parts by weight of a polyester resin comprising a dicarboxylic acid repeating unit and a diol repeating unit, The speckled area observed on one side is 30% or less.

The detailed description of the polyester resin, the polyester film, the lubricant, the first lubricant, the second lubricant, and the like is duplicated with the above description, so that the detailed description is omitted.

The calendaring polyester resin composition according to another embodiment of the present invention includes 0.1 to 10 parts by weight of a lubricant, based on 100 parts by weight of a polyester resin containing a dicarboxylic acid repeating unit and a diol repeating unit, wherein the The lubricant includes a first lubricant having a melting point or softening point of 100°C or lower.

The detailed description of the polyester resin, the polyester film, the lubricant, the first lubricant, the second lubricant, and the like is duplicated with the above description, so that the detailed description is omitted.

The polyester resin composition (1a) of the present invention is applied together with a suitable lubricant, along with excellent properties related to processability such as excellent adhesion to the calendering roll in the calendering process and good release property, and smooth bubble release. A polyester film 1b having excellent film properties such as transparency, low haze, and no orange peel phenomenon can be produced.

The above contents will be described in more detail by the following examples. The following examples are only for illustrating the present invention, and the scope of the examples is not limited to them.

Preparation of samples of Examples and Comparative Examples

1) Preparation of polyester resin chips

For the production of the polyester resin, a diol component and a dicarboxylic acid component were added to a 2500 L reactor equipped with a stirrer and an outlet condenser so that the final polymer amount was 2,000 kg. The pressure inside the reactor was increased to 2.0 kg/cm 2 using nitrogen gas, and the reactor was reacted while raising the temperature to 265°C. At this time, the resulting product was discharged to the outside while the esterification reaction proceeded, and then the reaction product was transferred to a polycondensation reactor equipped with a stirrer, a cooling condenser, and a vacuum system.

To the obtained esterification reaction product, antimony triglycolate was added as a metal polycondensation catalyst to be 300 ppm based on the amount of the antimony element, and triethyl phosphate (TEP) as a phosphorus stabilizer was added to be 500 ppm based on the elemental amount of phosphorus. Did. Thereafter, the reactor inside temperature and pressure were increased to 285 to 290°C and 50 mmHg, and a low vacuum reaction was performed for 40 minutes. Then, the diol component was discharged to the outside, and the pressure was gradually reduced to 0.1 mmHg again, and the reaction was performed under high vacuum to the maximum power value.

The polyester resin obtained in the polycondensation reaction was discharged and cut into chips to prepare polyester chips.

Terephthalic acid (TPA) was applied as the dicarboxylic acid compound, and diethylene glycol (DEG), neopentyl glycol (NPG), and/or cyclohexane dimethanol (CHDM) was applied as the diol compound. The molar ratio of the dicarboxylic acid: diol was applied at 1:1.05 to 3.0, but the neopentyl glycol was applied at 30 to 90 mol% based on the entire diol compound.

2) Preparation of polyester film

The composition according to Table 1 and Table 2 below was prepared by blending a lubricant with the polyester resin. On average, the composition was extruded at 200° C., kneaded, gelled, and calendered to prepare a 0.2 mm thick film. The types and properties of the applied lubricant are as shown below.

Glidant 1: Stearic acid-based lubricant. Melting point 68 ℃, viscosity 70 ℃ 9.87 mPas, density 0.94 g / cm ³

Lubricant 2: Montan wax-based lubricant. Melting point 82.5 (80 to 85) ℃, viscosity 120 ℃ 20 mPas or less, density 1.00 to 1.02 g / cm ³

Lubricant 3: A polyethylene oxide-based lubricant. Softening point of 98 ℃, viscosity of about 180 mPas at 140 ℃, density 0.92 to 0.94 g / cm ³

Lubricant 4: polyethylene-based lubricant. Softening point of about 180 mPas at 103 ℃ and viscosity 140 ℃, density 0.91 to 0.93 g / cm ³

Lubricant 5: Polyethylene-based lubricant. Softening point of 108 ℃, viscosity of about 750 mPas at 140 ℃, density 0.91 to 0.93 g / cm ³

Lubricant 6: Polyethylene-based lubricant. A softening point of about 1100 mPas at 109°C and a viscosity of 140°C, with a density of 0.91 to 0.93 g/cm ³

Evaluation of physical properties of samples of Examples and Comparative Examples

1) Process evaluation

The following items were evaluated while performing the calendaring process using the polyester resin composition.

-Releasability: It was evaluated based on the following criteria whether the sheet did not stick to the processing roll and released well during the process.

O: excellent releasability, △: moderate releasability, X: poor releasability

-Bank characteristics: Whether air bubbles are generated in the bank of the calendar or bubbles are well removed.

O: There is little air bubbles in the bank at high speeds of 15 m/min or more, △: Air bubbles are slightly slower, X: There are many air bubbles and air bubbles are slow.

-Transparency: The sheet produced by the calendering process was judged visually by transparency and the degree of cloudiness.

O: Transparency is high and no cloudiness is observed, △: Transparency is good, but some cloudiness is observed or no cloudiness is observed, but transparency is somewhat poor, X: Bad transparency or bad cloudiness.

-Roll speed: In the calendering process, roll speed is related to production efficiency and film quality. X was applied when the roll speed was less than 15 m/min, and indicated as O when applied at 15 m/min or more.

2) Light transmittance (TT, Total Transmittance)

It was measured with a haze meter (model name: SEP-H) manufactured by Nihon Semitsu Kogaku, Japan, and total light transmittance (%) was measured using a C-light source.

3) Haze evaluation

It was measured with a haze meter (model name: SEP-H) manufactured by Nihon Semitsu Kogaku, Japan, and a haze (%) was measured using a C-light source.

4) Speckled area

The sheet produced by the calendering process was placed in an oven at 80° C. for 24 hours, and then reflected under a fluorescent lamp to evaluate whether spots were generated on the observation area (average value after evaluation based on 21 * 29.7 cm ² * 3 sheets).

O: uneven area 10% or less, △: uneven area 10% or more and 50% or less, X: uneven area 50% or more

The evaluation results are shown in Table 1 and Table 2 below. Hereinafter, in Table 1 and Table 2, the content of the lubricant means parts by weight (phr, per hundred resin) of the lubricant based on 100 parts by weight of the polyester resin.

Lubricant (melting point, ℃) Composition 1 Composition 2 Composition 3 Composition 4 Composition 5 Composition 6 Gliding 1 (68) 0.5 - 0.4 4 - - Gliding 2 (82.5) - 0.5 0.2 - - - Gliding 3 (98) - - - - 4 - Gliding 5 (108) - - - - - 4 Totality 0.5 0.5 0.6 4.0 4.0 4.0 Heterogeneity X O O O O O Bank O △ △ X X X Transparency O O O △ X X Roll speed X △ O O O O Speckled area O O O X X X

Glide
(Melting point, ℃) Composition 7 Composition 8 Composition 9 Composition 10 Composition 11 Composition 12 Composition 13 Composition 14 Composition 15 Gliding 1 (68) - - - - - - - - 0.36 Gliding 2 (82.5) - - - - - - - 0.16 - Gliding 3 (98) 0.5 - - - 0.4 0.4 0.4 - 0.36 Gliding 4 (103) - 0.5 - - 0.4 - - 0.24 0.27 Gliding 5 (108) - - 0.5 - - 0.4 - - - Gliding 6 (109) - - - 0.5 - - 0.4 - - Totality 0.5 0.5 0.5 0.5 0.8 0.8 0.8 0.40 1.01 Heterogeneity O X △ △ O O O O O Bank △ O O O O O O O O TT 90.2 89.9 89.5 89.7 90.0 89.0 89.2 89.5 89.5 Hz 11.2 13.1 12.0 12.7 13.4 12.8 15.0 6.2 10.8 Roll speed O X X X O O O O O Speckled area O O O O O O O O O

Referring to Tables 1 and 2, the lubricant applied to the polyester resin composition applies only one type to control various properties such as releasability, bank characteristics, transparency, and roll speed (process speed) to a certain level or more. It was confirmed that it was not easy.

When two or more lubricants were applied to the polyester resin composition at the same time, it was confirmed that properties corresponding to normal or excellent for each item could be obtained. Particularly, when a first lubricant having a melting point or softening point of 2 or more lubricants and a second lubricant having a melting point or softening point of 100° C. or less and a second lubricant having a temperature of 100° C. or more and 160° C. or less are applied together, even if the amount of lubricant is increased, the level of staining on the sheet surface is small or insignificant. The ring process has advantageous properties for the production of polyester resins.

The preferred embodiments of the present invention have been described in detail above, but the scope of the present invention is not limited to this, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

1a: Polyester resin composition 1b: Polyester film
10: film production apparatus 100: blender
200: Calender roll 300: Cooler
400: winder

Claims (18)

A preparation step of preparing a calendering polyester resin composition containing 0.1 to 10 parts by weight of a lubricant based on 100 parts by weight of a polyester resin containing a dicarboxylic acid repeating unit and a diol repeating unit; A kneading step of kneading the calendering polyester resin composition in a blender to prepare a kneading composition; The kneading composition is introduced into a calender roll comprising two or more rollers rotating and rolling in opposite directions to each other, and the kneading compositions are rolled through a predetermined position between the calender rolls and formed into a sheet shape to form a polyester film. Rolling step for manufacturing; And the completion step of manufacturing a calendaring polyester film including a cooling process for cooling the polyester film; including,
The lubricant includes a first lubricant having a melting point or a softening point of 100° C. or less, to prepare a polyester film having a speckle area of 30% or less, and a method of manufacturing a polyester film.
According to claim 1,
The lubricant further comprises a second lubricant having a melting point or a softening point greater than 100°C and less than 160°C, and the method for producing a polyester film.
According to claim 1,
In the rolling step, the roll speed of the calender roll is applied to 15 m/min or more, a method of manufacturing a polyester film.
According to claim 1,
The lubricant further comprises a second lubricant, and the melting point or softening point of the second lubricant differs from the melting point or softening point of the first lubricant by 10° C. or higher.
According to claim 1,
The lubricant further comprises two or more first lubricants, and the first lubricant of the two kinds has a difference in melting point or softening point of 10°C or more from each other.
According to claim 1,
The polyester resin comprises a repeating unit of 20 to 90 mol% of an aliphatic or alicyclic diol based on the entire diol-based compound constituting the polymer chain of the polyester resin.
According to claim 1,
A method for producing a polyester film comprising a neopentyl glycol repeating unit as the diol repeating unit.
According to claim 1,
The polyester film has a haze value of 15% or less, the production method of the polyester film.
According to claim 1,
The polyester film has a total light transmittance (Total Transmittance) of 80% or more, the production method of the polyester film.
Based on 100 parts by weight of a polyester resin comprising a dicarboxylic acid repeating unit and a diol repeating unit, the lubricant contains 0.1 to 10 parts by weight of the lubricant, and the lubricant includes a first lubricant having a melting point or softening point of 100° C. or less, and A calendaring polyester film having an uneven surface area of 30% or less observed from one side.
The method of claim 10
The lubricant further comprises a second lubricant, and the melting point or softening point of the second lubricant is at least 10°C different from the melting point or softening point of the first lubricant, the calendering polyester film.
The method of claim 10
The polyester film has a total transmittance (Total Transmittance) of 80% or more, a calendaring polyester film.
The method of claim 10
The polyester resin comprises 20 to 90 mol% of an aliphatic or alicyclic diol repeating unit based on the entire diol compound constituting the polymer chain of the polyester resin, a polyester film.
A calendar containing 0.1 to 10 parts by weight of a lubricant based on 100 parts by weight of a polyester resin comprising a dicarboxylic acid repeating unit and a diol repeating unit, wherein the lubricant comprises a first lubricant having a melting point or softening point of 100° C. or less. Ring polyester resin composition.
The method of claim 14
The first lubricant is a calendaring polyester resin composition having a viscosity (Viscosity) of 20 mPa.s or less measured at 120°C.
The method of claim 14
The lubricant further comprises a second lubricant, and the melting point or softening point of the second lubricant is at least 10°C different from the melting point or softening point of the first lubricant, the calendering polyester resin composition.
The method of claim 14
The lubricant further comprises a second lubricant having a melting point or softening point of more than 100°C and 160°C or less, the calendering polyester resin composition.
The method of claim 14
The polyester resin contains 20 to 90 mol% of one diol repeating unit selected from the group consisting of a neopentyl glycol repeating unit, a cyclohexanedimethanol repeating unit, and combinations thereof as a diol repeating unit. The calendering polyester resin composition.

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