KR20000002226A - Transparent copolyester plate sheet - Google Patents

Abstract

PURPOSE: A copolyester plate sheet is provided which has transparency and excellent physical properties such as light transmittance and Hase characteristic. CONSTITUTION: The copolyester sheet, useful as transparent sound insulation wall and windowpane of high-rise building is prepared. For example, a mixture of terephthalic acid and ethylene glycol is melt-copolymerized with 3 mole % of 2,6-naphthalene dicarboxylate, 3 mole % of isophthalic acid and 3 mole % of 1,4-cyclohexanedimethanol based on the total acid component to give copolyester resin having intrinsic viscosity of at least 0.80, which is melted and extruded to give transparent sheet having light transmittance of 87% and Hase value of 3.1%.

Description

Transparency Copolyester Plate

The present invention relates to a transparent copolyester thick sheet sheet having excellent transparency and various physical properties, inexpensive manufacturing cost, and thick thickness.

Polyethylene terephthalate (hereinafter referred to as PET) resin has excellent physical properties, processability and economical efficiency, and thus is used in PET bottles, clothing fibers, films, and a wide variety of other fields. In recent years, the use of packaging materials is increasing rapidly due to excellent mechanical and chemical properties and high recyclability. One of the fields is a sheet, which is widely used as a thin sheet for vacuum forming (1 mm or less in thickness). However, a polyester sheet having a thickness of 1 mm or more has a problem in that it is difficult to manufacture due to inadequate crystallization characteristics and melting characteristics inherent in PET resin.

In general, in order to manufacture a thick sheet (hereinafter referred to as a thick sheet) with a polymer resin, the crystallization rate should be low, the crystallinity should be low, and a polymer resin having a moderately high melt viscosity for morphological stability in a molten state should be used.

As a new attempt to satisfy these required properties, it has been attempted to copolymerize other comonomers in PET to make modified polyester copolymers and has been successful in many parts.

As such, a method of preparing a modified polyester copolymer by copolymerizing another copolymerization monomer to PET may be broadly classified into two types.

First, a part of a terephthalate component, specifically dimethyl terephthalate (hereinafter referred to as DMT) or terephthalic acid (hereinafter referred to as TPA), which is used as an acid component in PET polymerization, is replaced with a diacid or a diacidester. The method to use is used. As the dieside or dieside ester, isophthalic acid (hereinafter referred to as IPA) or dimethylisophthalate (hereinafter referred to as DMI) is mainly used.

In other words, a polyester copolymer is prepared by copolymerizing [i] DMT or TPA, [ii] DMI or IPA and [i] ethylene glycol (hereinafter referred to as EG).

As shown in the following formulas (I) and (II), TPA and IPA differ only in the position where the functional group is attached to the benzene ring, and the rest of the structure is the same.

[General Formula (I) represents TPA, and General Formula (II) represents IPA.]

Therefore, IPA reacts well up to several mol% because of its good reactivity in the reaction system during PET polymerization. Thus, the copolyester copolymerized by several mol% of IPA or DMI has the structure of general formula (IV), and is different from the homopolyester which has the structure of general formula (III).

Due to such structural differences, the copolyester of the general formula (IV) interferes with the regularity of the molecular chain during the crystallization process, so that the crystallization rate is slow and the crystallinity is low. However, as the content of IPA or DMI increases, various physical properties of the resin are drastically lowered. When the content of IPA or DMI is reduced in order to prevent such deterioration of properties, the crystallization rate delay effect and the crystallinity deterioration effect required for copolyester thick sheet production cannot be obtained.

Due to such a problem, the copolyester of general formula (IV) copolymerizing about 3 mol% of IPA or DMI is currently used only for the manufacture of thick bottles or thin sheets.

Next, a method of substituting a part of ethylene glycol (EG), which is one of monomers used in PET polymerization, with 1,4-cyclohexanedimethanol (hereinafter referred to as CHDM) may be used. In other words, the copolymer is prepared by copolymerizing [i] DMT or TPA, [ii] EG, and [iii] CHDM, and then preparing a transparent copolyester thick sheet using the same.

CHDM has the same structure as formula (V) and has a longer molecule length than EG, which impedes the regularity of crystals in the copolyester, thus slowing down the crystallization rate and decreasing crystallinity.

In addition, since CHDM does not break the molecular chain like IPA, even if the copolymerization content is increased, the reactivity and the physical properties of the polymer are not significantly reduced, and CHDM also has a high melt viscosity required for the manufacture of the thick sheet of the polymer resin.

However, in order to obtain a crystallization rate, low crystallinity characteristics, and relatively high melt viscosity characteristics that are sufficiently slow to enable the formation of a transparent thick sheet, CHDM should be copolymerized in a large amount up to about 30 mol%. As a result, the manufacturing cost of the product is also very expensive, and there is a significant limitation in the range of its use. In addition, in order to obtain sufficient mechanical properties, a high degree of polymerization is essential. When a large amount of CHDM is copolymerized, the degree of crystallinity is very low. Therefore, in order to obtain sufficient degree of polymerization, a considerable effort is required, such as having to equip special polymerization equipment. Eastman Chemical Co. produces and sells these polymers under the trade name PETG.

The present invention is to provide a transparent copolyester thick sheet excellent in various physical properties such as light transmittance, haze (Haze) properties, and low cost.

The present invention relates to a transparent copolyester thick sheet sheet which is excellent in transparency and various physical properties, and is inexpensive to manufacture and can be usefully used as a substitute for a transparent soundproof wall, a high-rise building glass window, and the like.

More specifically, the present invention relates to an acid component composed of a terephthalate component, a 2,6-naphthalenedicarboxylate component and an isophthalate component, [ii] ethylene glycol (EG) alone or ethylene glycol (EG); A glycol component, which is a mixture of 1,4-cyclohexanedimethanol (CHDM), is made of copolymerized copolymer, and relates to a transparent copolyester thick sheet having a light transmittance of 83% or more and a haze value of 5% or less.

The present invention relates to a 2,6-naphthalenedicarboxylate component which is essentially a part of the acid component when copolymerizing the resin for the sheet, in order to control the thermal and rheological properties requirements of the polymers required for molding the transparent copolyester thick sheet. And isophthalate components, and optionally 1,4-cyclohexanedimethanol (CHDM) as part of the glycol component.

In the present invention, as the terephthalate component, dimethyl terephthalate (DMT) or terephthalic acid (TPA) is mainly used.

As the 2,6-naphthalenedicarboxylate component, dimethyl-2,6-naphthalenedicarboxylate (hereinafter referred to as NDC) or 2,6-naphthalenedicarboxylic acid (hereinafter referred to as NDA) is mainly used. . In addition, isophthalate (IPA) or dimethyl isophthalate (DMI) is mainly used as the isophthalate component.

In order to manufacture a transparent thick sheet using a polymer material, the following basic properties are required.

First, since it is processed in the molten state, it is necessary to have stability that the molecular chain is not easily decomposed in the molten state.

Second, it must have proper melting characteristics. In other words, in order to maintain the shape of the thick sheet in the molten state, a high melt viscosity is required, but if it is too high, it becomes difficult to process, so a high viscosity is required within the processable degree.

Third, the crystallization behavior should be appropriate. The thicker the sheet, the harder the rapid cooling. Therefore, in order to prevent crystal formation that degrades the transparency of the sheet, it is preferable that the crystallization rate is slow and that the material itself has low crystallinity. However, complete amorphous materials may impede the improvement of mechanical strength, so that some degree of cleanup is required within the range of physical properties.

As a material satisfying only a part of the above required characteristics, it is difficult to manufacture a thick sheet, it is desirable to satisfy all the possible characteristics.

Hereinafter, the present invention will be described in more detail.

The present invention relates to an acid component composed of (EG) TPA or DMT as a terephthalate component, (ii) NDC or NDA as a 2,6-naphthalenedicarboxylate component and (A) IPA or DMI as an isophthalate component and EG or Copolyester resin is prepared by melt copolymerizing a glycol component, which is a mixture of EG and CHDM, and then extrudes it with an existing extrusion sheet molding machine to prepare a copolyester thick sheet.

Dimethyl-2,6-naphthalene dicarboxylate (NDC) used as part of the acid component in the present invention has a structure of formula (VI), 2,6-naphthalene dicarboxylic acid (NDA) is a general formula ( Iii) has a structure.

NDC or NDA is mainly used to polycondensate with EG to make polyethylene naphthalate (hereinafter referred to as PEN) of general formula, which is a high functional polymer.

Such PEN shows very excellent properties in almost all physical properties, such as heat resistance, UV protection, gas barrier properties, tensile strength and hydrolysis resistance, compared to PET. However, NDC or NDA, which is a main raw material, is expensive and has difficulty in commercial production, and is used only in limited fields such as high-performance video tape films and special containers. Therefore, recently, methods such as copolymerization and blending with PET have been introduced in order to secure a competitive price / performance ratio, but the scope of development is still limited.

However, in the present invention, the monomer for copolymerizing NDC or NDA for the purpose of adjusting the thermal and rheological properties required for forming the transparent copolyester thick sheet sheet is not intended to improve the characteristics such as heat resistance and UV protection as in the prior art. Used as. That is, NDC or NDA as a monomer for copolymerization is used to appropriately delay the crystallization rate for preparing the transparent thick sheet, to reduce the crystallinity of the resin, and to secure the melt viscosity necessary for maintaining the strength in the molten state for easy molding. will be.

More specifically, the present invention first melt-copolymerizes an acid component consisting of (i) DMT or TPA, (ii) NDC or NDA, and (iii) IPA or DMI with a glycol component which is a mixture of EG or EG and CHDM. A random copolyester resin is prepared having a level of 0.70 to 0.90.

The content of 2,6-naphthalenedicarboxylate component in melt copolymerization is preferably 8 mol% or less relative to the total acid component, but is not particularly limited in their content. In general, however, the higher the content of the 2,6-naphthalenedicarboxylate component, the lower the crystallinity of the resin itself. If the content of the 2,6-naphthalenedicarboxylate component is too high to lower the crystallinity of the resin itself, the obtained resin after melt polymerization may be subjected to solid phase polymerization again to adjust the intrinsic viscosity (IV) of the resin. The content of isophthalate component in the melt copolymerization is preferably 0.5 to 5 mol% relative to the total acid component. On the other hand, when using CHDM with EG as the glycol component, the content of CHDM is preferably 15 mol% or less relative to the total acid component.

In the random copolyester resin structure of the present invention, the portion containing NDC or NDA instead of TPA or DMT and the portion containing CHDM instead of EG have a longer length, but the angle of the molecular chain is maintained as it is. Rather than the structure, it is similar to PETG, a product of Eastman Chemical Co., described earlier. As a result, the mechanism on the crystallization properties is similar to that of PETG, a product of Eastman Chemical Co., which is more advantageous for thick sheet forming.

Such local nonuniformity of the molecular chain acts as an obstacle to crystal formation requiring regularity, which slows down the crystallization rate and lowers the crystallinity. In addition, while obtaining the same effect as the polymerization does not lower the reactivity during the polymerization, the polymerization is easy, PEN physical properties are added to the PET and PETG physical properties is further improved physical properties. As a result, the copolyester resin of the present invention copolymerized by the above-described method satisfies both the thermal and rheological properties of the resin required in the transparent thick sheet forming process, so that the transparent thick sheet can be easily formed using these resins. can do. Next, after supplying said copolyester resin to an extrusion sheet molding machine, these resins are melt-extruded and the transparency copolyester thick sheet of this invention is manufactured.

The transparent copolyester thick sheet of the present invention has a light transmittance of 83% or more and a haze value of 5% or less. In addition, the transparent copolyester thick sheet of the present invention has a cooling crystallization calorific value (ΔHmc) of 1.0 J / g or less and a visible light refractive index of 1.35 to 1.70.

As described above, since the transparent copolyester thick sheet of the present invention has a large amount of cooling crystallization heat, crystallization proceeds actively during polymer cooling.

In addition, the transparent copolyester thick sheet of the present invention has a melt viscosity of 900 to 8,000 poise measured at a shear rate of 1,000 sec −1 at 270 ° C., and 100 sec − at 270 ° C. The melt viscosity measured by the shear rate of 1 is 1,700-30,000 poise.

Various physical properties of the transparent copolyester thick sheet described above are measured by the following method.

Haze value (%) and light transmittance (%)

After cutting a certain portion of the thick sheet is measured by a turbidity measuring instrument (Haze-Meter, NDH-300A- Nippon Denshoku).

Cooling crystallization calories (J / g)

Using a differential scanning calorimeter (DSC), the solution is allowed to stand at 290 ° C for at least 3 minutes and then measured while cooling at 20 ° C / min.

Visible light refractive index

Measured with Abbe refractometer.

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

Example 1

3 mol% of NDC, 3 mol% of IPA, and 3 mol% of CHDM were added to the mixture of TPA and EG, followed by melt copolymerization to prepare a copolyester resin. ) Is 0.80. The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 6 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 2

8 mol% of NDC, 3 mol% of IPA, and 8 mol% of CHDM are added to the mixture of TPA and EG, followed by melt copolymerization to prepare a copolyester resin having an intrinsic viscosity of 0.75. The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 8 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 3

8 mol% of NDC, 1 mol% of IPA, and 15 mol% of CHDM are added to a mixture of TPA and EG, followed by melt copolymerization to prepare a copolyester resin having an intrinsic viscosity of 0.71. The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 10 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 4

5 mol% of NDA and 4 mol% of IPA are added to the mixture of TPA and EG, followed by melt copolymerization to prepare a copolyester resin, followed by solid phase polymerization to give an intrinsic viscosity (IV) of 0.88. . The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 4 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 5

8 mol% of NDA and 2 mol% of IPA are added to the mixture of TPA and EG, followed by melt copolymerization to prepare a copolyester resin, followed by solid phase polymerization to give an intrinsic viscosity (IV) of 0.85. . The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 8 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 6

5 mol% of NDA and 1 mol% of IPA relative to the total acid component are added to the mixture of TPA and EG, followed by melt copolymerization to prepare a copolyester resin having an intrinsic viscosity of 0.71. The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 6 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 7

5 mol% of NDA and 3 mol% of IPA relative to the total acid component are added to the mixture of TPA and EG, followed by melt copolymerization to prepare a copolyester resin (A) having an intrinsic viscosity of 0.85. Meanwhile, 8 mol% NDA and 1 mol% IPA are added to a mixture of TPA and EG, followed by melt polymerization to prepare a copolyester resin (B) having an intrinsic viscosity of 0.82. The copolyester resins (A) and (B) prepared above were mixed to 1: 1, fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 6 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 8

5 mol% of NDC and 3 mol% of DMI are added to the mixture of DMT and EG, followed by melt copolymerization to prepare a copolyester resin, followed by solid phase polymerization to give an intrinsic viscosity (IV) of 0.88. . The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 4 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 9

8 mol% of NDC and 1 mol% of DMI are added to the mixture of DMT and EG, followed by melt copolymerization to prepare a copolyester resin, followed by solid phase polymerization to give an intrinsic viscosity (IV) of 0.85. . The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 8 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 10

4 mol% of NDC and 1 mol% of DMI are added to the mixture of DMT and EG, followed by melt copolymerization to prepare a copolyester resin having an intrinsic viscosity of 0.71. The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 6 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 11

5 mol% of NDC and 3 mol% of DMI are added to the mixture of DMT and EG, followed by melt copolymerization to prepare a copolyester resin (A) having an intrinsic viscosity of 0.85. Meanwhile, 8 mol% of NDC and 4 mol% of DMI are added to a mixture of DMT and EG, followed by melt polymerization to prepare a copolyester resin (B) having an intrinsic viscosity of 0.82. The copolyester resins (A) and (B) prepared above were mixed to 1: 1, fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 6 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 12

3 mol% of NDC, 3 mol% of DMI, and 3 mol% of CHDM were added to the mixture of DMT and EG, followed by melt copolymerization to prepare a copolyester resin, followed by solid phase polymerization to obtain intrinsic viscosity (IV). ) Is 0.80. The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 6 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 13

8 mol% of NDC, 1 mol% of DMI, and 8 mol% of CHDM are added to the mixture of DMT and EG, followed by melt copolymerization to prepare a copolyester resin having an intrinsic viscosity of 0.75. The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 8 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 14

8 mol% of NDC, 1 mol% of DMI, and 15 mol% of CHDM are added to the mixture of DMT and EG, followed by melt copolymerization to prepare a copolyester resin having an intrinsic viscosity of 0.71. The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 10 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 15

5 mol% of NDC and 3 mol% of IPA are added to the mixture of TPA and EG, followed by melt copolymerization to prepare a copolyester resin, followed by solid phase polymerization to give an intrinsic viscosity (IV) of 0.88. . The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 4 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 16

8 mol% of NDC and 1 mol% of IPA are added to the mixture of TPA and EG, followed by melt copolymerization to prepare a copolyester resin, followed by solid phase polymerization to give an intrinsic viscosity (IV) of 0.85. . The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 8 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 17

5 mol% of NDC and 1 mol% of IPA relative to the total acid component are added to the mixture of TPA and EG, followed by melt copolymerization to prepare a copolyester resin having an intrinsic viscosity of 0.71. The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 6 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 18

A copolyester resin (A) having an intrinsic viscosity of 0.85 is prepared by adding 5 mol% of NDC and 3 mol% of IPA to the mixture of TPA and EG followed by melt copolymerization. Meanwhile, 8 mol% of NDC and 1 mol% of IPA are added to a mixture of TPA and EG, followed by melt polymerization to prepare a copolyester resin (B) having an intrinsic viscosity of 0.82. The copolyester resins (A) and (B) prepared above were mixed to 1: 1, fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 6 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 19

5 mol% of NDA and 2 mol% of DMI are added to the mixture of DMT and EG, followed by melt copolymerization to prepare a copolyester resin, followed by solid phase polymerization to give an intrinsic viscosity (IV) of 0.88. . The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 4 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 20

8 mol% of NDA and 1 mol% of DMI are added to the mixture of DMT and EG, followed by melt copolymerization to prepare a copolyester resin, followed by solid phase polymerization to give an intrinsic viscosity (IV) of 0.85. . The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 8 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 21

8 mol% of NDA and 0.5 mol% of DMI are added to the mixture of DMT and EG, followed by melt copolymerization to prepare a copolyester resin having an intrinsic viscosity of 0.71. The copolyester resin thus prepared is fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 6 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

Example 22

5 mol% of NDA and 4 mol% of DMI are added to the mixture of DMT and EG, followed by melt copolymerization to prepare a copolyester resin (A) having an intrinsic viscosity of 0.85. Meanwhile, 8 mol% NDA and 1 mol% DMI are added to a mixture of DMT and EG, followed by melt polymerization to prepare a copolyester resin (B) having an intrinsic viscosity of 0.82. The copolyester resins (A) and (B) prepared above were mixed to 1: 1, fed to an extrusion sheet molding machine, and then melted and extruded to prepare a transparent sheet having a thickness of 6 mm. The results of measuring various physical properties of the prepared transparent sheet are shown in Table 1.

<Table 1> Property Measurement Results

division Thickness (mm) Light transmittance (%) Haze value (%) Cooling Crystallization Calorie (J / g) Visible light refractive index Melt Viscosity (Poise) For X For Y Example 1 6 87 3.1 0.90 1.40 900 2,000 Example 2 8 85 4.1 0.80 1.53 4,000 10,000 Example 3 10 82 5.0 0.85 1.67 8,000 25,000 Example 4 4 86 2.9 0.98 1.49 1,000 3,000 Example 5 8 85 3.5 0.82 1.55 3,000 10,000 Example 6 6 85 4.0 0.79 1.59 8,000 25,000 Example 7 6 84 4.1 0.80 1.51 5,000 15,000 Example 8 4 87 3.1 1.00 1.50 1,000 3,000 Example 9 8 86 4.0 0.85 1.65 4,000 10,000 Example 10 6 86 4.2 0.80 1.69 8,000 25,000 Example 11 6 85 4.4 0.83 1.60 6,000 15,000 Example 12 6 87 3.1 0.90 1.40 900 2,000 Example 13 8 85 4.1 0.80 1.53 4,000 10,000 Example 14 10 82 5.0 0.85 1.67 8,000 25,000 Example 15 4 87 3.1 1.00 1.50 1,000 3,000 Example 16 8 86 4.0 0.85 1.65 4,000 10,000 Example 17 6 86 4.2 0.80 1.69 8,000 25,000 Example 18 6 85 4.4 0.83 1.60 6,000 15,000 Example 19 4 86 2.9 0.98 1.49 1,000 3,000 Example 20 8 85 3.5 0.82 1.55 3,000 10,000 Example 21 6 85 4.0 0.79 1.59 8,000 25,000 Example 22 6 84 4.1 0.80 1.51 5,000 15,000

In Table 1, in the melt viscosity, X represents the case where the share rate is 1,000 sec-1 and Y represents the case where the share rate is 100 sec-1.

The transparent copolyester thick sheet of the present invention has excellent light transparency and haze characteristics in spite of its thick thickness and is excellent in transparency. In addition, it is excellent in various physical properties such as mechanical properties, and manufacturing cost is also low. As a result, the transparent copolyester thick sheet of the present invention can be usefully used in many industrial fields such as transparent soundproof walls, glass windows of high-rise buildings, and alternatives to automobile glass windows.

In addition, the present invention can obtain the following effects.

First, it is possible to adjust the melt viscosity is easy to manufacture a thick sheet.

The present invention has a large change in melt viscosity depending on the content of 2,6-naphthalenedicarboxylate component (NDC or NDA) and CHDM, and the 2,6-naphthalenedicarboxylate component (NDC or NDA) and CHDM The wide range of content control allows the preparation of copolyesters of a wide variety of properties. In particular, the width of the resin can be controlled in the molten state can be easily overcome the limitation of the moldable thickness. As a result, a transparent thick sheet sheet having a thickness of about 10 mm, which was difficult to manufacture with a conventional polyester resin, can be easily produced.

Second, there is no physical property deterioration with increasing 2,6-naphthalenedicarboxylate component (NDC or NDA) and CHDM content.

Third, it is easy to adjust the crystallization characteristics.

In the copolyester of the present invention, since the crystallization characteristics are different depending on the content of 2,6-naphthalenedicarboxylate component (NDC or NDA) and CHDM, the content control and polymerization degree of NDC, NDA and CHDM are different. By controlling the crystallization rate and the heat of crystallization of the resin itself can be arbitrarily adjusted. As a result, it is easy to manufacture a transparent thick sheet of a desired thickness.

Fourth, it is economic.

When only CHDM is used as a copolymerization monomer, to prepare a thick sheet, the concentration of CHDM should be added up to about 30 mol%. However, the present invention simultaneously uses 2,6-naphthalenedicarboxylate component (NDC or NDA) as a copolymerization monomer. It is economical because the use of expensive CHDM can be reduced.

Fifth, the physical properties of the prepared sheet is excellent.

Various excellent properties of PEN are expressed to a considerable level, which is excellent in weather resistance, mechanical properties, and chemical properties.

Claims (9)

[Iii] an acid component composed of a terephthalate component, a 2,6-naphthalenedicarboxylate component and an isophthalate component, [ii] ethylene glycol (EG) alone or ethylene glycol (EG) and 1,4-cyclohexane A transparent copolyester thick sheet of which a glycol component, which is a mixture of dimethanol (CHDM), is made of copolymer copolymerized, has a light transmittance of 83% or more and a haze value of 5% or less. The transparent copolyester thick sheet according to claim 1, wherein the amount of cooling crystallization (ΔHmc) of the copolyester is 1.0 J / g or less. The transparent copolyester thick sheet according to claim 1, wherein the melt viscosity of the copolyester measured at a shear rate of 100 sec-1 at 270 ° C is 1,700 to 30,000 poise. The transparent copolyester thick sheet according to claim 1, wherein a melt viscosity of the copolyester measured at a shear rate of 1,000 sec −1 at 270 ° C. is 900 to 8,000 poises. The transparent copolyester thick sheet according to claim 1, having a thickness of at least 3 mm. The transparent copolyester thick sheet according to claim 1, wherein the copolyester has a visible light refractive index of 1.35 to 1.70. The transparent copolyester thick sheet according to claim 1, wherein the terephthalate component is dimethyl terephthalate (DMT) or terephthalic acid (TPA). The transparent copolyester thick sheet according to claim 1, wherein the 2,6-naphthalenedicarboxylate component is dimethyl-2,6-naphthalenedicarboxylate (NDC) or 2,6-naphthalenedicarboxylic acid (NDA). . The transparent copolyester thick sheet according to claim 1, wherein the isophthalate component is isophthalic acid (IPA) or dimethylisophthalate (DMI).