KR100363869B1 - Manufacturing method of laminated polyester film - Google Patents

Abstract

The present invention relates to a method of manufacturing a laminated polyester film, which prevents the formation of voids on the surface during film production, thereby reducing the occurrence of large particles due to cutting, thereby improving the dropout phenomenon in manufacturing a magnetic tape. In addition to exhibiting electronic properties, the object of the present invention is to provide a method for producing a laminated polyester film having low roughness, good slidability and winding property, and excellent properties in transparency and gloss. The present invention to achieve a method for producing a polyester film composed of ethylene terephthalate or ethylene naphthalate, a polyester resin having an IV of 0.5 to 0.7 and filler particles having an average particle diameter of 0.5 to 1.0μm 0.1 to the resin weight Resin A layer contained at 3% by weight, and polyester number having IV of 0.5 to 0.7 The resin B layer containing 0.1 to 3% by weight of the filler particles having an average particle diameter of 1.0 to 2.0 μm and the polyester resin having an IV of 0.5 to 0.7 are 0.1 to 3.0 μm of the filler particles having an average particle diameter of 2.0 to 3.0 μm. The resin C layer containing 3% by weight and the resin D layer containing 0.1 to 3% by weight of inorganic particle filler having an average particle size of 3.0 to 4.0 μm in polyester resin having IV of 0.5 to 0.7 are not adjacent to each other. The present invention provides a method for producing a laminated polyester film, characterized in that at least uniaxially stretching after stacking three or more layers by lamination or overlapping.

Description

The method of producing a layed polyester film

The present invention relates to a polyester film, and more particularly, to prevent the formation of voids on the surface of the film by the filler added with the resin in the production of the polyester film and to reduce the occurrence of large particles as well as the same The present invention relates to a method for producing a laminated polyester film that can improve glossiness by increasing the glossiness at the time of roughness and preventing stress concentration on the surface of the film to lower the friction coefficient.

Saturated linear polyester films represented by polyethylene terephthalate have excellent mechanical properties, heat resistance, weather resistance, electrical insulation, chemical resistance, etc., and thus are widely used in a wide range of fields such as packaging, photography, electrical, magnetic tape, and the like.

In particular, the polyester film used for the magnetic is required to have a high running characteristics and electronic properties, and as a conventional technique for securing the running characteristics of the film as described above, inorganic fillers such as calcium carbonate are generally added to the polyester resin Molding techniques have been introduced, but when the inorganic filler is added in an excessive amount, a relatively low electronic characteristic problem occurs.

For this reason, in order to reduce the roughness of the film by reducing the amount of filler added to improve the electronic properties, the contact energy on the surface of the polymer increases, so that the main product is very poor due to the so-called blocking phenomenon that the films stick to each other. do.

As a method for improving such a phenomenon, a method of securing a stable running property by applying a coating liquid containing a lubricating agent on the film during the manufacture of the polyester film is adopted, but when the amount of the activating agent is increased, the running performance is improved. On the other hand, there is a disadvantage in that the yield is poor due to the manufacturing process.

Also, in the case of the filler, a large particle filler is prepared in a slurry form from a small size, and is collectively added during chip polymerization, so when a large particle filler is located on the surface of the film, voids are formed on the surface of the film, so that the slitting process or Due to the generation of chips during post-processing of the magnetic film coating process, the dropout increases and sometimes falls off during the driving of the magnetic tape, thereby causing a problem in that the wear resistance of the film is very deteriorated.

In addition to the magnetic film described above, transparency is managed as one of the most important qualities when used as a base material for packaging films. In order to secure such high transparency, conventionally, no haze is added by not adding a filler during film production. To reduce the and to increase the gloss is used, but in this case, the winding is impossible due to the blocking phenomenon when winding the film.

Therefore, a method of applying a coating liquid containing a slip agent made of inert inorganic particles onto a film to reduce the coefficient of friction is wound up. However, this method also rapidly increases the breakage of the film due to blocking tension when the thickness of the film becomes thin. The poor coating process causes various quality problems during post-processing.

The present invention is to solve the problems of the prior art as described above, by preventing the formation of voids on the surface during film production to reduce the occurrence of large particles due to the cutting to improve the drop out (dropout) phenomenon in the manufacture of magnetic tape It is an object of the present invention to provide a method for producing a laminated polyester film that not only exhibits excellent electronic properties but also has low roughness, good slidability and winding property, and excellent properties in transparency and gloss.

The present invention for achieving the above technical problem is a laminated polyester film of three or more layers manufactured by using a known co-extrusion technique, the thickness of each resin layer-containing filler by varying the thickness of each co-extruded resin layer It provides a laminated polyester film characterized in that.

That is, the present invention provides a polyester resin having an IV (intrinsic viscosity) of 0.5 to 0.7 and a filler particle having an average particle diameter of 0.5 to 1.0 μm in a method for producing a polyester film having a repeating unit composed of ethylene terephthalate or ethylene naphthalate. The resin A layer containing 0.1 to 3% by weight of the resin and the polyester resin having an IV of 0.5 to 0.7 contain 0.1 to 3% by weight of the filler particles having an average particle size of 1.0 to 2.0 μm. The average particle diameter of the resin B layer and the polyester resin of IV of 0.5 to 0.7 are contained in the resin C layer and IV of 0.5 to 0.7. After the resin D layer containing 0.1 to 3% by weight of inorganic particle filler of 3.0 to 4.0μm is laminated in three or more layers, each independently or in duplicate, so as not to be adjacent to each other, at least Provided is a method for producing a laminated polyester film characterized by uniaxial stretching.

The reason for limiting the intrinsic viscosity (IV) of the polyester resin used in the present invention to 0.5 to 0.7 is that when the intrinsic viscosity is lower than 0.5, there is a problem that biaxial stretching is not easy due to breakage in the unstretched sheet state, and exceeds 0.7 This is because there is a difficulty in extruding because the screw is heavily loaded during extrusion.

At the time of lamination of the polyester film as described above, the particle diameter of the filler particles contained in each layer resin gradually decreases from the center layer to the outer layer.

Examples of preferred lamination configurations include resin A layer / resin B layer / resin A layer, resin A layer / resin B layer / resin C layer or resin A layer / resin B layer / resin C layer / resin B layer / resin A layer. It can be laminated in the form, and if you want to use it for packaging, resin B layer / resin C layer / resin D layer, resin B layer / resin C layer / resin D layer / resin C layer It can be laminated in various forms such as a resin B layer.

In this case, in the case of the resin layer used as the outermost layer, it is preferable that the layer thickness is not equal to or more than twice the average particle diameter of the filler particles. This is because the filler is uniformly distributed in one layer in the outer layer of the film. When the thickness of the outer layer is smaller than the average particle diameter of the filler when forming the film, the filler protrudes to the surface of the film during stretching in the film manufacturing process to form voids. This is because such voids may increase dropout and lower scratch resistance in magnetic applications, as well as increase haze in packaging, thereby lowering optical characteristics.

What is necessary is just to comprise the thickness after extending | stretching each said layer so that the film thickness in each layer may be a particle size of a filler.

The method for producing each polyester resin is not particularly limited, but the conventional polymerization method of polyester is applied as it is, but the polymer filler content may be determined by adjusting the amount of additive in the polymerization step. In addition, the filler particles added to the polyester in order to control the surface properties such as the runability, winding properties of the polymer can be selected by adding a suitable insoluble inorganic particles or organic particles to the polyester, such as inorganic particles Any of known particles such as calcium carbonate, dolomite, glass spare, fiberglass, talc, kaolin, mica, silica, barium sulfate, aluminum silicate and alumina may be used.

In addition, organic particles insoluble in polyester include a monovinyl compound having one aliphatic unsaturated bond in a molecule and a monovinyl compound having two or more aliphatic unsaturated bonds in a molecule and a crosslinking agent having at least two aliphatic unsaturated bonds in a molecule. Copolymers with the compound and fine powders of thermosetting phenol resins, thermosetting epoxy resins, thermosetting urea resins, benzoguanamine resins and fluorine resins can be used, and there are no particular restrictions on the type and amount of these compounds.

The method for producing a polyester sheet having a structure of three or more layers using the polyester resin used for each resin layer as described above is not particularly limited, and may be a conventionally known coextrusion method. By supplying the molten polymer to the multi-manifold die or the feedblock die to fix the plate-like molten polymer to the rotating cooling drum, a continuous sheet can be produced.

In the case of using the multi-manifold method, the thickness of the outer layer is controlled by adjusting the die lip gap of the outer layer. In the case of the feed block method, the thickness of the outer layer is controlled by adjusting the discharge amount and the choke bar of each layer.

The sheet thus manufactured is continuously subjected to longitudinal stretching, but it may be used in one or multiple stages of stretching. Between longitudinal stretching and transverse stretching, in-line coating may be performed to improve the adhesiveness, antistatic property, etc. of the film within the range without departing from the surface characteristics of the present invention. It is okay.

The polyester film obtained by the present invention has a specific size of filler in a specific position, and has excellent electronic characteristics and excellent running performance and does not cause scratches, so that the polyester film has all functions as a magnetic tape for high density recording, and the packaging film has a low haze. It is possible to produce a film having excellent optical transmittance and glossiness and excellent running property.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples.

<Example 1>

Resin A Manufacturing Example

100 parts of dimethyl terephthalate, 70 parts of ethylene glycol and 0.05 part of calcium acetate were placed in a reactor and subjected to a transesterification reaction. After about 4 hours, the calcium carbonate having an average particle diameter of 0.5 μm in the system where the transesterification reaction was substantially completed 0.3 part of particles were added, followed by 0.06 part of trimethyl phosphate and 0.04 part of antimony trioxide, followed by polymerization for 5 hours by a conventional method to obtain a polyester resin having an IV of 0.630.

Resin B Manufacturing Example

The polyester resin A was carried out in the same manner as in the production example, but in the case of the calcium carbonate, an average particle diameter of 1.0 μm was used.

Resin C Manufacturing Example

The polyester resin A was carried out in the same manner as in Preparation Example, but the calcium carbonate was used having an average particle diameter of 2.0 μm.

After drying the respective resins A, B and C obtained from the respective polyester resin preparation examples, a co-extrusion process is performed by a conventional co-extrusion polyester film manufacturing method, and resin C is sheeted using a feed block. The resin B was co-extruded into an amorphous laminated polyester sheet by discharging the resin B to both surfaces of the resin C layer and the resin A to each surface portion of the resin B layer.

Subsequently, the amorphous laminated polyester sheet was stretched 3.5 times in the longitudinal direction under a temperature condition of 90 ° C., then stretched 4.3 times in the transverse direction at 110 ° C., and then subjected to a heat treatment at 210 ° C. for 3 seconds to obtain a thickness of the resin A layer. Is 0.5μm, resin B layer is 1.5μm, resin C layer is 5μm, and resin A layer / resin B layer / resin C layer / resin B layer / resin A layer is sequentially stacked. A laminated polyester film for magnetic recording was prepared. The average roughness of the surface of the polyester film thus prepared was 12 nm and the macroparticles, scratch resistance, activity, wear resistance, and electronic properties were measured according to the method defined in the following experimental example, and the results are shown in Table 1 below.

Experimental Example

Floor thickness

The cross section of the film was cut with a microzoom and measured with an electron microscope.

-IV-

The polymer was dissolved in ortho-chlorophenol and measured by an automatic viscosity meter (SKYVIS-5000) of SKC.

Average particle size

Particles were photographed with 50 sheets of a scanning electron microscope at 50 sites, measured by an image analysis device, and calculated by arithmetic mean particle size of each site.

Giant Particles

At the time of bonding two films, the projections of 1.0 μm or more formed in the size of 50 × 50 were observed under a microscope to measure the projections of 1.0 μm or more formed in the size of 50 × 50.

◎: 0

○: 1 to 3

△: 4 to 5

×: 6 or more

Scratch resistance

The film was visually observed in the polarization field to observe the number of scratches per 10 cm in width.

◎: 0

○: 1 to 3

△: 3 to 10

×: 10 or more

Active activity

TBT-300D, a tape running tester of the Yokohama Systems Research Institute, Japan, is used.The fixed guide pin is used to make the contact angle 135 ^O by using a tape slitting the film 1/2 inch wide at a driving speed of 3.3 cm / sec and a pulling force of 30 g. The running friction coefficient was measured using the following formula (1) from the winding tension when (material SUS303) was passed through 90m.

k = (2.303 / θ) log (Ti / To)

Here, θ is the contact angle between the film and the guide pin, Ti is the pulling tension and To means the winding tension.

◎: k value is -0.057 or more

○: k value is -0.122 or more

△: k value is -0.172 or more

X: k value is -0.172 or less

Wear resistance

At the end of the measurement of the activity, the degree of the powder on the fixing guide pin was evaluated in four steps.

◎: Almost no powder

○: 1 to 5% of the guide pin area

Δ: 5 to 10% of the guide pin area

X: 10% or more of the guide pin area

Electronic Characteristics (S / N Ratio)

After the video tape was manufactured using the polyester film prepared according to the present invention, the size of the noise signal was measured using a BR6400U type VTR deck of Nihon VICTA and a signal output of 4 megahertz.

◎: 1.0dB increase compared to normal state

○: 0.5dB higher than the reference state

△: equivalent to standard condition

×: bad compared to the reference state

Haze

The measurement was carried out according to the method defined in ASTM D1003. (Measurement diameter: 25 mm, fall angle: 2.5 degrees)

Glossiness

It was measured by the method defined in ASTM D 523. A black diameter was used as the reference diameter and the measurement angle was 60 degrees.

Friction coefficient

It was measured by the method defined in ASTM D 1894.

<Example 2>

After drying each of the resins A and B obtained from the polyester resin manufacturing example, a co-extrusion process is performed by a conventional co-extrusion polyester film manufacturing method, and the resin B is discharged to the center of the sheet using a feed block. The resin A was coextruded into an amorphous laminated polyester film by discharging to both sides of the resin B layer.

Subsequently, the amorphous laminated polyester film was stretched 3.5 times in the longitudinal direction under a temperature condition of 90 ° C., then stretched 4.3 times in the transverse direction at 110 ° C., and then subjected to a heat treatment at 210 ° C. for 3 seconds to obtain a thickness of the resin A layer. A laminated polyester film for self-recording having a three-layer structure in which a resin A layer / resin B layer / resin A layer formed of 1.0 mu m and a resin B layer having a thickness of 8.0 mu m was sequentially laminated.

The average roughness of the surface of the polyester film thus prepared was 8 nm and the macroparticles, scratch resistance, activity, wear resistance, and electronic properties were measured according to the method defined in the above experimental example, and the results are shown in Table 1 below.

<Example 3>

The same method as in Example 1, except that the average particle diameter of the calcium carbonate used in the production of the resins A, B and C was 1.0 μm, 2.0 μm and 3.0 μm, respectively, and the weight parts were added in 0.1 parts by weight, respectively. The thickness of each of the resin A layer, the resin B layer, and the resin C layer was 1.0 μm, 2.0 μm, and 3.0 μm, respectively, to prepare a packaging film.

The average roughness of the surface of the polyester film thus prepared was 30 nm and the haze, glossiness and coefficient of friction were measured according to the method defined in the above experimental example, and the results are shown in Table 1 below.

Comparative Example 1

100 parts of dimethyl terephthalate, 70 parts of ethylene glycol and 0.05 part of calcium acetate were placed in a reactor and subjected to a transesterification reaction. After about 4 hours, the calcium carbonate having an average particle diameter of 0.5 μm in the system where the transesterification reaction was substantially completed 0.3 parts of particles and 0.3 parts of calcium carbonate particles having an average particle diameter of 1.0 μm and 0.3 parts of calcium carbonate particles having an average particle diameter of 2.0 μm were added, followed by addition of 0.06 parts of trimethylphosphate and 0.04 parts of antimony trioxide, followed by polymerization for 5 hours by a conventional method. The reaction was carried out to obtain a polyester resin having an IV of 0.630.

After drying the prepared polyester resin and performing an extrusion process by a conventional method for producing a polyester film, extruded into an amorphous laminated polyester sheet, and stretched 3.5 times in the longitudinal direction under a temperature condition of 90 ℃ 110 ℃ Was stretched 4.3 times in the transverse direction, and then heat-treated at 210 ° C. for 3 seconds to prepare a polyester film for magnetic recording having a thickness of 9 μm.

The average roughness of the surface of the polyester film thus prepared was 18 nm, and the macroparticles, scratch resistance, activity, wear resistance, and electronic properties were measured according to the method described in the above experimental example, and the results are shown in Table 1 below.

Comparative Example 2

100 parts of dimethyl terephthalate, 70 parts of ethylene glycol and 0.05 part of calcium acetate were placed in a reactor and subjected to a transesterification reaction. After about 4 hours, the calcium carbonate having an average particle diameter of 1.0 μm was substantially obtained in the system where the transesterification reaction was completed. 0.3 parts of particles and 0.3 parts of calcium carbonate particles having an average particle diameter of 2.0 µm and 0.3 parts of calcium carbonate particles having an average particle diameter of 3.0 µm were added, followed by addition of 0.06 parts of trimethyl phosphate and 0.04 parts of antimony trioxide, followed by polymerization for 5 hours by a conventional method. The reaction was carried out to obtain a polyester resin having an IV of 0.630.

After drying the prepared polyester resin and performing an extrusion process by a conventional method for producing a polyester film, extruded into an amorphous laminated polyester sheet, and stretched 3.5 times in the longitudinal direction under a temperature condition of 90 ℃ 110 ℃ After stretching 4.3 times in the transverse direction in the heat treatment at 210 ℃ for 3 seconds to prepare a packaging polyester film having a thickness of 9μm.

The average roughness of the surface of the polyester film thus prepared was 50 nm and the haze, glossiness or coefficient of friction was measured according to the method defined in the above experimental example, and the results are shown in Table 1 below.

division Roughness (Ra, nm) Large particles Scratch resistance Activity Wear resistance Electronic properties Haze Glossiness Coefficient of friction Example 1 12 ◎ ◎ ○ ○ ○ - - - Example 2 8 ◎ ◎ ○ ○ ◎ - - - Example 3 30 - - - - - 1.0 180 0.45 / 0.55 Comparative Example 1 18 ○ ○ ○ △ △ - - - Comparative Example 2 50 - - - - - 1.0 160 0.60 / 0.69

As can be seen from the results of Table 1, the film of Examples 1 and 2 according to the present invention has a very low average roughness of 12 and 8, respectively, so that the reactivity is very excellent, and the winding property is greatly improved. It was found that the degree of generation of macroparticles was very low, the scratch resistance and the abrasion resistance were excellent, and the dropout occurred less and the electronic properties were also very good.

However, in Comparative Example 1 prepared in a single layer by mixing at a time without separating the layer according to the particle size range of the filler particles, the average roughness was relatively low, but the winding property was good.

In addition, the polyester film of Example 3 prepared for the purpose of packaging by increasing the size of the filler particles to be added is excellent in the gloss can be used as a high-quality packaging material, and the friction coefficient was shown to be excellent in antistatic properties, In Comparative Example 2, the average roughness of 50 nm was very large, and thus the winding property was lowered and the gloss was lowered. Therefore, it was difficult to apply it as a high quality packaging material. It can be seen that phenomena such as blocking due to static electricity can easily occur.

As described above, the polyester film having a laminated structure of three or more layers provided by the present invention, as described above, produces a film having a low void and a low roughness and good running property, thereby providing both an improvement in electronic properties and runability. In order to limit the filler size and thickness of each layer of the co-extruded polyester film, the projections of a certain size on the surface of the film are uniformly distributed, thereby preventing the concentration of stress, thereby reducing the contact area, and thus exhibiting excellent mobility. .

Claims (7)

In the method for producing a polyester film composed of ethylene terephthalate or ethylene naphthalate, a polyester resin having an IV of 0.5 to 0.7 and filler particles having an average particle diameter of 0.5 to 1.0 μm are contained at 0.1 to 3% by weight based on the weight of the resin. Resin B layer containing 0.1 to 3% by weight of filler particles having a mean particle size of 1.0 to 2.0 μm in the resin A layer and a polyester resin having an IV of 0.5 to 0.7 and a polyester having an IV of 0.5 to 0.7. Resin C layer containing 0.1 to 3% by weight of filler particles having an average particle diameter of 2.0 to 3.0 μm in the resin and inorganic particles filler having an average particle diameter of 3.0 to 4.0 μm in a polyester resin having an IV of 0.5 to 0.7. Laminate comprising at least uniaxial stretching after lamination of three or more layers of the resin D layer containing the weight% independently or overlapping with each other so as not to be adjacent to each other Method for producing a polyester film. The method of claim 1, wherein the laminated polyester film comprises a resin A layer / resin B layer / resin C layer / resin B layer / resin A layer. The method of claim 1, wherein the laminated polyester film comprises a resin A layer / resin B layer / resin A layer. The method of claim 1, wherein the laminated polyester film is composed of a resin B layer / resin C layer / resin D layer / resin C layer / resin B layer. The method for producing a laminated polyester film according to any one of claims 1 to 4, wherein the thickness after stretching of each resin layer is greater than or equal to the particle size of the filler particles added to each resin layer. The thickness of the resin A layer is 0.5 to 1.0μm, the thickness of the resin B layer is 1.0 to 2.0μm, the thickness of the resin C layer is 2 to 3.0μm and the thickness of the resin D layer is 3.0 Method of producing a laminated polyester film, characterized in that from 4μm. The method of claim 5, wherein the filler particles are inorganic or organic particles insoluble in polyester, and calcium carbonate, dolomite, glass spare, fiberglass, talc, kaolin, mica, silica, barium sulfate, aluminum silicate, alumina, thermosetting phenol. A method for producing a laminated polyester film, characterized in that the resin, thermosetting epoxy resin, thermosetting urea resin, benzoguanamine resin or fluorine resin alone or as a mixture.