KR0130611B1 - Polyester film - Google Patents

Abstract

The polyester film is at least one axis-oriented and is characterized by including the followings as an additive agent: barium sulfate 1.0 - 30wt% in reference to the polyester coated with zinc compound 0.01 - 0.15wt% in reference to the barium sulfate; fluorescent organic pigment 0.05 - 1.0wt% in reference to the polyester; and an inorganic pigment 0.01 - 1.0wt% in reference to the barium sulfate in order to control Col-b value.

Description

Polyester film

The present invention relates to a polyester film, and in detail, has excellent printing properties and antistatic properties on the surface, and less discoloration due to work and sunlight, and thus can be used as a white board, various magnetic cards, photo papers, printing materials, high-quality wrapping papers, and the like. It relates to an ester film.

Generally, pre-paid magnetic cards such as communication cards such as telephone cards, credit cards such as bank cards, and transportation cards such as underground cut cards are mainly manufactured from polyvinyl chloride and paper. come.

Cards made of polyvinyl chloride as a basic raw material are thick, so it is unsatisfactory to carry several cards at the same time, and because of their low impact strength, flexibility, and flame resistance, they are easy to be destroyed by external impacts, and due to heat generated during printing. The disadvantage is that the film is easily deformed. In addition, cards manufactured using paper have poor water resistance, mechanical strength, durability, and the like, and thus problems are more serious. In view of such a problem, in recent years, polyester films based on polyester as various magnetic cards have been increasingly used.

Among the polyesters, polyethylene terephthalate is chemically and physically stable, has high mechanical strength, and has excellent flame resistance, durability, chemical resistance, and electrical insulation, so that it can be used for medical treatment, picking, magnetic recording media, capacitor, packaging, photo film, It is widely used not only for labels but also for various molded products.

Recently, many studies have been conducted outside of Korea to use polyester films having high transparency and surface gloss suitably for magnetic cards. A white pulley film produced by mixing a high refractive index inorganic compound filler to control high transparency of a polyester film and adding a brightener to enhance whiteness is the most advanced and commercially available.

However, the white polyester film for magnetic cards manufactured as described above is easily discolored due to sulfidation when exposed to sunlight under high temperature conditions or for a long time, and thus is not suitable for high quality cards, and due to the characteristics of the polyester film, static electricity is easily generated and accumulated. In the printing process, problems such as printing unevenness and poor adhesion of ink are issued. In addition, the most fatal problem is that the loss of various valuable information stored in the magnetic card may cause loss of reliability. In addition, the existing titanium compound added to maintain the film concealability is expensive and the manufacturing cost is high, as well as agglomeration easily occurs at room temperature and humidity, there are many difficulties in the process.

Looking at the technology developed to solve the various problems as described above while utilizing the excellent properties of the polyester film is as follows.

Japanese Patent Application Laid-Open No. 62-243120 and Japanese Patent Laid-Open No. 2-206622 disclose a technique of adding polyester inorganic particles, and Japanese Patent Application Laid-open No. 2-185532 disclose a technique using barium sulfate alone. Japanese Unexamined Patent Publication No. Hei 3-50241 et al. Discloses a technique in which a polyolefin resin is blended with polyester and then stretched by adding a mixture of barium sulfate and calcium carbonate.

However, the results of these studies only suggested the possibility of using inorganic materials such as barium sulfate or titanium compounds, and did not solve the problems caused during industrial application.

It is an object of the present invention to provide a polyester film suitable for use in various cards by improving the above-mentioned problems, which is white, opaque, has excellent printing and antistatic properties, and is less discolored by heat and sunlight.

In order to achieve the above object, in the present invention, at least 60% by weight of the main repeating unit is a polyester film having an intrinsic viscosity of 0.4 to 0.9d1 / g made of ethylene terephthalate, and is 0.01 to about barium sulfate as an additive. Barium sulfate coated with 0.15% by weight of zinc compound was 1.0-30% by weight based on polyester, fluorescent organic pigment was 0.05-1.0% by weight based on polyester, and the following formula (1) Inorganic pigments to adjust 0.02 to 1.0% by weight and Col-b value of the compound represented by the formula and the sulfonic acid metal salt derivative having an acid value of 1.0 mgKOH / g or less represented by the following general formula (2), respectively, based on polyester: It provides at least a uniaxially oriented polyester film comprising 0.01 to 1.0% by weight based on barium.

(In formula, R1 is a C1-C10 alkali group, R2 is a C8-C25 alkali group, M is an alkaline earth metal or an alkali metal.) It is preferable that especially the said barium sulfate has a particle diameter of 0.01-5 micrometers.

In addition, the inorganic pigment is preferably an inorganic substance having a hexagonal structure having a composition of αK · βNa · γCa · δAl · εSi (α: β: γ: δ: ε (1: 2: 1: 1: 3).

In the present invention, in order to solve the fatal defect of the white polyester film as described above, using barium sulfate surface-treated with zinc to suppress the discoloration of the film and by using a sulfone compound and an anionic antistatic agent together The crystal structure was controlled to give antistatic properties and at the same time excellent ink adhesion. Colors were adjusted using inorganic pigments.

The polyester of the present invention has an intrinsic viscosity of 0.4 to 0.9 d1 / g measured at a concentration of 0.3 grams per 25 milliliters of autochloropace at 35 ° C. If the intrinsic viscosity is less than 0.4d1 / g, breakage occurs frequently during stretching, which leads to a significant drop in productivity, and a decrease in physical properties such as mechanical strength in the final film, and a melt viscosity when the intrinsic viscosity exceeds 0.9 dl / g. Since the rise is very high, productivity in the post-process due to the difficulty in the manufacturing process, such as extrusion instability is greatly reduced so as to be in the above range. Preferably, the intrinsic viscosity is set to 0.5 to 0.8 d1 / g.

In this invention, polyester polycondenses the acid component which has aromatic thicarboxylic acid as a main component, and the glycol component which has alkylene glycol as a main component. Specific examples of the aromatic dicarboxylic acid used as the acid component include dimethyl terephthalate, terephthalic acid, isophthalic acid, naphthalene-ticarboxylic acid, cyclohexane-dicarboxylic acid, digenoxyethane group carboxylic acid and diphenyl. Dicarboxylic acid, diphenyl ether dicarboxylic acid, cyantrazene dicarboxylic acid α, β-bis (2-chlorophenoxy) ethane-4-4-dicarboxylic acid, and the like. Terephthalate and terephthalic acid are preferable. Specific examples of the alkylene glycol include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, hexylene glycol and the like, and among these, ethylene glycol is particularly preferable.

The polyester of the present invention is a homopolyester of at least 60% by weight of polyethylene-terephthalate and may be copolymerized within 40% by weight. Specific examples of the copolymerization components include diol compounds such as diethylene glycol, propylene glycol, neopentyl glycol, polyethylene glycol, p-xylene glycol, 1.4-cyclohexanedimethanol, and 5-sodium sulforezocin and adipic acid, 5 -Dicarboxylic acid components, such as sodium sulfoisophthalic acid, polyfunctional dicarboxylic acid components, such as trimellitic acid and a pyromellitic acid, etc. are mentioned.

As the inorganic filler in the present invention, barium sulfate having a crystal form of tetragonal crystals (a = 7.5 Å b = 8.8 Å angle = 90 °), crystal structure, and an average particle diameter of 0.01 to 5 μm is used. Dominates whiteness and light transmittance.

The degree of whiteness of the film to be produced is about 80 to 110%. When the degree of whiteness is less than 80%, the film has a yellow color, resulting in poor printing quality. When the whiteness is more than 110%, the film has a blue color on the surface. This is because the senses fall. Preferably the whiteness is 85 to 105%.

And transmittance | permeability of a film shall be 0.5 to 2.0%. This is because when the light transmittance exceeds 2.0%, the film is less visible due to the small concealability of the film, and the problem is that the strength of the film is weakened because a large amount of micro bubbles must be contained in order for the light transmittance to be less than 0.5. to be. More preferably, the light transmittance is made 0.8 to 1.5%.

The zinc compound is coated on the barium sulfate to improve the light resistance of the film, and the amount of the zinc metal compound is 0.01 to 0.15% by weight based on the barium sulfate. This is because when the zinc compound component is less than 0.01% by weight, the light resistance effect is lowered, and when the zinc compound component is more than 0.15% by weight, the side effect of lowering the thermal stability is generated. More preferably, it is effective to coat the zinc compound in an amount of 0.03 to 0.05% by weight.

The amount of the barium sulfate coated with zinc may vary depending on the thickness and use of the polyester film, but is 1.0 to 30 wt% based on the polyester. If the addition amount of barium sulfate is less than 1.0 neutral light%, the effect of addition is insignificant, and if it is higher than 3% by weight, the mechanical properties such as the strength and flexibility of the film are lowered. Therefore, the effect of a large amount of input will not be obtained.

The fluorescent organic pigment in the present invention is a bisbenzoazole system, which absorbs light energy in the ultraviolet region and disperses energy by dissolving energy into the short wavelength region of visible light, thereby improving the appearance of low short wavelength reflectance when only inorganic materials are added. . In the case where the reflectance at 440 nm, which is the short wavelength region of visible light, is 75% or more, it is appropriate that the appropriate amount of the main organic pigment is 0.05 to 1.0% by weight based on polyester. In other words, if the dose is less than 0.05% by weight, there is almost no increase in reflectance at 440nm, and if the dose is more than 1.0% by weight, the reflectance at 440nm is too high, resulting in a white-white film.

Barium sulfate used as an inorganic filler in the present invention has a small specific gravity and excellent dry dispersibility as well as low market price compared to the titanium compound has a number of advantages in the development of the use, Co1-L value is good but blue light emitted Due to the disadvantage that the envy after printing is deteriorated, it is necessary to use an inorganic pigment for the purpose of improving the Co-b value.

The inorganic pigments used in the present invention are hexagonal, structured inorganic substances having a composition of αK, βNa, γCa, δAl, εSi (α: β: γ: δ: ε (1: 2: 1: 1: 3), 0.01 to 1.0% by weight, based on the amount of barium sulfate, which is less than 0.1% by weight, does not improve the col-b value and becomes yellow when it exceeds 1.0% by weight. Because.

The antistatic agent in the present invention uses a compound represented by the general formula (1) and a sulfonic acid metal salt derivative having an acid value of 1.0 mgKOH / g or less represented by the general formula (2) together, and by adding them, The surface resistance should be 10 ¹² Ω or less.

In the above formula, R ₁ is an alkyl group having 1 to 10 carbon atoms, R ₂ is an alkyl group having 8 to 25 carbon atoms, and M is an alkaline earth metal or an alkali metal including Li, Na, and Mg.

The antistatic agent compound of the general formula (1) is added to 0.02 to 1.0% by weight based on polyester, which is fine fisheye is formed on the surface of the film when the addition amount thereof is less than 0.02% by weight. This is because not only the physical properties are greatly reduced, but there is almost no improvement in the antistatic properties. When the content exceeds 1.0% by weight, the decomposition of the polyester occurs and the mechanical properties and the whiteness of the film are greatly reduced. More preferably, the addition amount is 0.05 to 0.8 wt%.

Specific examples of the compound of the general formula (1) include sodium 3.5-kigarbo-methoxybenzenesulfonate, sodium 3.5-dicarbo-ethoxybenzene sulfonate, sodium 3.5-dicarbo-pentoxybenzene sulfonate, lithium 3.5-dica Rebo-ethoxybenzenesulfonate, potassium 3.5-dicarbo-pentoxy benzene sulfonate and the like.

The antistatic agent compound of the general formula (2) used in the present invention is added in an amount of 0.02 to 1.0 wt% based on the polyester. In consideration of the antistatic properties, mechanical properties, etc. of the film, it is preferable to make the addition amount thereof 0.05 to 0.8% by weight. Examples of the compound of the general formula (2) include sulfonic acid metal salt derivatives such as potassium octylbenzenesulfonate, potassium nonylbenzenesulfonate, potassium undecylbenzenesulfonate, and mixtures thereof.

Since the sulfonic acid metal salt derivative of the general formula (2) has excellent heat resistance and excellent compatibility with the compound of the general formula (1), a polyester prepared by adding to the polyester together with the compound of the general formula (1) The film has excellent antistatic properties. In addition, the film tension of the film is increased, the adhesion to the ink and the coating liquid is also very excellent. For reference, the surface tension of the film does not improve the adhesion to the ink and various coating liquids below 45 dyne / cm.

In order to produce a film having excellent antistatic properties, mechanical properties, ink and adhesion to various coating liquids, the compounds of the general formulas (1) and (2) must be used simultaneously as the antistatic agent.

In addition to the above polyesters, known additives such as ultraviolet absorbers, heat stabilizers, polycondensation catalysts, dispersants, electrostatic agents, crystallization accelerators, travel agents, anti-locking agents, etc. do not impair the effects of the present invention. May optionally be added within.

Two methods can be used to introduce various additives added in the present invention. That is, a method in which each additive is slurried with ethylene glycol to the required concentration in the final film and directly introduced into the esterification or transesterification reaction or polycondensation reaction may be used, or firstly, all or part of the additive may be used at a high concentration. After preparing the injected polyester polycondensate, there is a method of manufacturing a master batch chip (high concentration chip) in which an additive is not administered in the extrusion molding process or some additives are mixed with a polyester polycondensate injected at a high concentration. Both of the above methods can be applied, but it is preferable to add the second method in order to reduce contamination of the polymerization reactor and increase dispersibility of the additive.

Hereinafter, a preferred embodiment of the present invention will be described in detail. Various performances of the films produced in each example and comparison were evaluated by the following method. (Hereinafter, the weight percentages mentioned in the Examples are based on polyester.)

(1) glossiness

ASTM D523 (Standard Diameter: Black Diameter, Measurement Strength: 60 Degrees)

(2) whiteness

JIS-L-1015 (reflectance of wavelength 450nm: B%, reflectance of 550nm: G%)

Whiteness = 4B-3G

(3) light transmittance

ASTM Dl003 (Diameter: 25mm, Scattering Angle: 2.5 °)

(4) 440 nm reflectance

Reflectance measurement value at 440nm of visible light wavelength using light source color shade (Japan Corporation, Model: SZS-∑80)

(5) Antistatic property (antistatic property)

Measure the surface resistance using the insulation resistance meter of U.S. Hewlett (20 ℃, RH: 65%, applied voltage: 550V, unit: Ω)

(6) light resistance evaluation

Measure the Color-L value by using a color difference meter after exposure to ultraviolet rays for 30 hours under the condition of 60 ℃ using a light and primary color difference meter (Japan Corporation Corporation, Model: SZS-∑80).

(7) fairness

The slitting state of the film cross section was judged as follows.

0: When the cross section is uniform and clean

(Triangle | delta): When there is a slight omission phenomenon but uniformity is good overall.

×: severe dropout

(8) printability

The 3rd degree printing state on the film surface was judged as follows.

0: Print status is clear and border is clear

(Triangle | delta): Although the part of the printing state clarity and a boundary is somewhat unclear, it is favorable overall.

X: Print state clarity and boundaries between colors are unclear.

(Example 1)

Dimethyl terephthalate and ethylene glycol are mixed in a 1: 2 equivalent ratio and a transesterification catalyst is added to prepare a polyethylene terephthalate monomer (bis-2-hydroxyethylterephthalate). An average particle diameter of 0.3 µm, a tetragonal crystal structure, 20% by weight of barium sulfate coated with 0.03% by weight of zinc stearate based on barium sulfate to improve light resistance, and 0.10% by weight of an oxazole-based fluorescent pigment 3.5-dicarboe 1.5% by weight of oxybenzenesulfonate, 0.15% by weight of potassium octylbenzenesulfonate, 0.1% by weight of bis 2.4-di-t-butylphenylpentaerythritoldiphosphite and triphenylphosphate, and 3.5-di-t-tetrakis 0.15% by weight of butyl-hydroxyphenyl-propanoyl-oxymethyl-methane, based on the barium sulfate compound, αK.βNa.γCa.δAl.εSi (α: β: γ: δ: ε (1: 2: 1: 3: 3) 0.20% by weight of an inorganic pigment having a hexagonal structure and a general polycondensation catalyst were added to complete the polycondensation reaction to prepare a polyester resin having an intrinsic viscosity of 0.62d1 / g. Then dried, melted and pressed in accordance with conventional methods And by stretching the amorphous sheet and then formed into a longitudinal drawing mystery, transverse stretching ratio to 3.5 times, respectively to prepare a biaxially stretched polyester film having a thickness of 188㎛.

The physical properties of the obtained film are shown in Table 1. From Table 1, this film has glossiness 45%, light transmittance 0.8%, Co1-L value 91%, Col-b value, -0.1, 440nm reflectance 88%, light transmittance 0.8%, and the properties and light resistance, fairness, printability, etc. It can be confirmed that this is excellent.

(Example 2-8)

It was carried out in the same manner as in Example 1, except that the addition amount of the additive was changed as shown in Table 1, and the physical properties of the film thus prepared were good as in Table 1.

(Comparative Example 1-15)

It was carried out in the same manner as in Example 1, but was carried out by changing the type of additives and the amount thereof added as shown in Table 1 and the physical properties of the film thus prepared was poor as shown in Table 1.

Discoloration of the film was suppressed by adding the barium sulfate compound surface-treated with zinc according to the present invention, and the light resistance of the film was improved by coating with the barium sulfate zinc compound, and the antistatic agent was added. By controlling the crystal structure of the film to impart antistatic properties and improve ink adhesion, the Co1-b value is improved by adding an inorganic pigment, and the short wavelength reflectance is increased by adding a fluorescent organic pigment. It has become possible to produce white polyester films that have been improved to have properties.

In other words, the polyester film according to the present invention has high whiteness, opacity, excellent light resistance, printing characteristics and antistatic properties, and less discoloration due to heat and sunlight. It can be used as a wrapping paper.

Claims (4)

In a polyester film having an intrinsic viscosity of 0.4 to 0.9d1 / g of at least 60% by weight of the main repeating unit made of ethylene terephthalate, barium sulfate coated with 0.01 to 0.15% by weight of zinc compound based on barium sulfate as an additive Is 1.0 to 30% by weight based on polyester, fluorescent organic pigments to 0.05 to 1.0% by weight based on polyester, the compound represented by the following general formula (1) as an antistatic agent and the following general formula (2) 0.02 to 1.0 wt% of sulfonic acid metal lead derivative having an acid value of 1.0 mgKOH / g or less, based on polyester, and an inorganic pigment for controlling Co1-b value, respectively, based on 0.01 to 1.0 weight of barium sulfate At least uniaxially oriented polyester film comprising%. (Wherein R ₁ is an alkali of ₁ to 10 carbon atoms, R ₂ is an alkali of 8 to 25 carbon atoms, and M is an alkaline earth metal or an alkali metal) The polyester film according to claim 1, wherein the barium sulfate has a particle diameter of 0.015 mu m. The inorganic pigment is an inorganic substance having a hexagonal structure having a composition of αK.βNa.γCa.δAl.εSi (α: β: γ: δ: ε (1: 2: 1: 1: 3). Polyester film, characterized in that. The polyester film according to any one of claims 1 to 3, wherein the polyester film has a whiteness of 80 to 110% and a light transmittance of 0.5 to 2.0%.