KR100553183B1 - Heat shrinkage polyester film - Google Patents

Abstract

 The present invention relates to a heat shrink polyester film for use in plastic bottles, glass bottles, battery packaging, integrated packaging of several containers, etc., in particular, a heat shrink polyester film having excellent shrinkage properties and good antistatic properties and printability. The purpose is to provide.

The present invention is a method for achieving the above object, the glass transition temperature is 67 ℃ or more and the water containing a polyester-based water dispersion binder represented by the formula (I) and natural or synthetic layer silicate inorganic particles having antistatic properties Disclosed is a heat-shrink polyester film characterized by applying and drying a dispersion on at least one side of a film.

Heat Shrink, Polyester, Antistatic

Description

Heat Shrink Polyester Film {HEAT SHRINKAGE POLYESTER FILM}

The present invention relates to a heat shrinkable polyester film, and more particularly, to an antistatic and fusion resistant coating applied with an antistatic mixed dispersion composition during the stretching process or during stretching and heat fixation in the manufacturing process of the polyester shrink film. It is related with this excellent polyester film.

Heat-shrinkable films are being used in a variety of applications, including plastic bottles, glass bottles, battery packaging, and packaging for multiple containers. PVC, polystyrene (PS), polypropylene (PP), and the like have been used as the material, and recently, the use of polyester is gradually increasing according to reports that PVC produces dioxins, which are environmental pollutants.

In general, polyethylene terephthalate (PET), which is widely used, has excellent heat resistance, weather resistance, and chemical resistance, and a sufficient shrinkage rate can be obtained by stretching or changing the temperature of a thermal process, but a shrinkage label is produced due to rapid shrinkage stress or shrinkage rate. , When used in products such as bottles cause process problems due to shrinkage non-uniformity at the time of shrinkage, in addition to the distortion of the print letters, bar code (bar code) is not recognized in the final product.

Korea as a way to address these shortcomings Patent Application No. 1986-0011602, Korean Unexamined Patent 2001-0011259, Japanese Patent Application Publication No. 57-42726, Small 59-97175, Small 62-91555, Small 64-4326, Flat 3-81338, Flat 3-142224, Flat 5- 318587, Pyeong 7-174684, Pyeong 7-205283, Pyeong 7-216109, Pyeong 9-239834, etc., are terephthalic acid, the main component of polyethylene terephthalate, and dicarboxylic acid components other than ethylene. It is proposed that butanediol, 1,4-cyclohexanedimethanol, 1,3-propanediol, etc. can be used as a copolymerization component to improve shrinkage uniformity.

However, the shrinkage film is able to secure the uniformity of shrinkage due to the copolymerization component, but due to poor printing due to fusion of labels by high-temperature filling in the post-processing process, dust adhesion due to static electricity, and electrostatic adhesion between labels. Problems such as deterioration of workability in the continuous labeling process.

Generally, as a method of imparting antistatic property to a polyester film, US Pat. Nos. 4,263,263 and 4214035 propose a method of using various polymers such as an acrylic polymer containing a quaternary ammonium salt compound. When applied to, the problem is that the quaternary ammonium salt, which is a single molecule, is deteriorated in printability due to transfer to the opposite side, or that the antistatic agent on the surface is washed by water in the washing process due to its poor water resistance, thereby losing its function. Occurs.

 The present invention has been made to solve the above-mentioned conventional problems, excellent shrinkage characteristics when used for labeling, overall coating of various containers, heat shrinkage with good printability while retaining antistatic properties through coating processing The purpose is to provide a film.

The present invention relates to a polyester-based water dispersion binder (A) having a carboxylic acid in a main chain represented by the following formula (I) having a glass transition temperature of 67 ° C. or higher, and a natural or synthetic layered silicate having antistatic properties. Disclosed is a heat-shrink polyester film characterized in that an antistatic aqueous dispersion of a mixed composition of inorganic particles (B) is applied and dried on at least one surface of a stretched or heat-fixed film during the stretching process.

[Formula I]

Wherein R is an aryl or alkyl group,

R ', R "is - (CH ₂₎ an alkylene or polyoxyalkylene group having an alkylene group, a side chain expressed by n-, x, y is an integer from 1 to 100.

Hereinafter, the present invention will be described in detail.

As the polyester of the present invention, for example, at least one selected from terephthalic acid, isophthalic acid, sebacic acid, anipic acid, oxalic acid, malonic acid, glutaric acid, pimeric acid and pyromellitic acid as a dicarboxylic acid component And a pyromellitic anhydride etc. can be used as a carboxylic acid provision component in a principal chain.

Ethylene glycol, 1,4-butanediol, 1,3-propanediol of alkylene group without side chain as diol component, 2,2-dimethyl-1,3-propanediol, 2-methyl- of alkylene group with side branch One or more components selected from the group consisting of 1,3-propanediol, diethylene glycol, polyethylene glycol, polytetramethylene glycol are used. The molecular weight of polyester is suitably 1000 to 20,000. When the molecular weight is too small, it is difficult to secure water resistance and to serve as a sufficient binder, and when the molecular weight is too large, it is difficult to make an aqueous dispersion. The obtained polymer is added with an organic solvent such as isopropyl alcohol or n-butyl cellusolve, organic amine, and water to form a dispersion. The glass transition temperature of the polyester resin is preferably 67 ° C. or higher, but when the glass transition temperature is lower than 67 ° C., it is not good in terms of fusion prevention and water resistance.

Examples of inorganic particles having antistatic properties are representative of layered silicate inorganic particles, and the multilayer silicate inorganic particles that can be used include natural and synthetic inorganic particles. These are multilayer silicate inorganic particles composed of a silica tetrahedron sheet and an alumina or magnesium octahedron sheet, and typically include one or more inorganic particles selected from the group of smectite or montmorillonite. The solid content of the polyester resin and the antistatic inorganic particles in the coating liquid is preferably in the range of about 0.2 to 20% by weight. If it is less than 0.2% by weight, it is difficult to obtain excellent antistatic properties, and it is more than 20% by weight. In use it can adversely affect the heat shrink of the film.

The amount of the layered silicate particles is preferably in the range of about 20 to 1,000 parts by weight with respect to 100 parts by weight of the polyester resin as the binder to be used. When used less than the antistatic property in the range of 10 ⁷ ~ 10 ¹² Ω / square expressed by surface resistance can not be obtained.

These one or more minerals may typically have at least one naturally occurring cation or primary cation such as potassium, calcium, or sodium present in the gallery attracted to the negative charge of the clay surface and may contain a small amount of water. It can conduct static electricity accumulated on the surface by external or friction. The natural moisture content and internal charge of about 10% has the characteristics to maintain excellent antistatic properties even at a wide range of humidity levels. In particular, the larger the nano-dispersion is possible, the better the antistatic and transparency can be obtained.

The antistatic coating composition of the present invention can be applied onto a film during or after the stretching step in the film production process of the shrink film resin. The coating in the stretching step is stretched from 0 to 4 times in the longitudinal direction, and then applied to a thickness of about 0.01 to 10 μm using a gravure roll or wire bar application method, and then preheated at 70 to 100 ° C. and 3 to 5 times in the transverse direction. The shrinkage film can be stretched to produce a heat shrink film having a shrinkage ratio of at least one direction of 30% or more. When applying the coating composition of the present invention on the stretched film can also be applied and dried under similar conditions to impart an antistatic function.

The heat shrinkable polyester film substrate of the present invention is a polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, copolyester containing cyclohexane dimethanol, 2,2-dimethyl-1,3-propanediol (NPG ) And at least two or more copolyesters containing 2-methyl-1,3-propane diol (NPG) and the like. It can obtain by extruding the copolyester obtained by throwing in all the polymerization processes. Shrinkage characteristics can be obtained by adjusting draw temperature, heat setting temperature, and draw ratio so that at least one direction shrinkage may be 30% or more.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, wherein the measurement and evaluation of physical properties were carried out by the following method.

1. Hot water shrinkage

The 10 cm × 10 cm shrink film was soaked in hot water at 90 degrees for 10 seconds, and then taken out to calculate the length.

Thermal contraction rate (%) = (10-film length after treatment) × 100

2. surface resistance

After leaving the sample for 24 hours at 23 ° C. and 52% RH, the antistatic properties (OHM / square) were evaluated with a surface resistance meter.

3. Haze

A polyester film sampled at a size of 10 cm × 10 cm is placed vertically on an HAMATIZER DIGITAL HAZEMETER (manufactured by Nippon Densoku Co., Ltd.), and the light having a wavelength of 400 to 700 nm is transmitted in a direction perpendicular to the vertically placed sample. The value shown was measured.

At this time, the haze value is calculated by the following equation and displayed on the haze meter.

      Haze (%) = (1- DF / TT) × 100

DF: amount of scattered light TT: total amount of transmitted light

4. Coating uniformity

The appearance of the coated film was visually observed to evaluate the degree of uniform coating.

○: When the coating state is uniform

X: coating state is nonuniform or poor compatibility

5. Lacquer Adhesion

An oil-based lacquer for evaluation, consisting of 10 parts of n-butanol, 250 parts of methyl cellosolve, 10 parts of methyl ethyl ketone, 25 parts of cellulose acetate butyrate, and 3 parts of rhodamine ratio (dye), was coated with wire bar # 18 on the coated film sample. After sufficiently drying in a drier at 90 ° C. for 1 minute, 100 scales are drawn on the surface using a cross cutter, and then an adhesive tape is attached and peeled off. At this time, the evaluation was based on the remaining number of scales did not peel off of 100 scales.

Ex) 100: No peeling off (excellent)

      0: All peeled off (defective)

6.water resistance

  After soaking in running water for 60 seconds, the surface resistance was measured after drying at room temperature.

It was evaluated as the difference between the log value of the surface resistance (R ₂ ) and the log value of the surface resistance (R ₁ ) before the treatment.

 log (R2) -log (R1) ≤2.0 Good water resistance (○)

 log (R2) -log (R1)> 2.0 insufficient water resistance (×)

< Production and Coating Method of Polyester Film Substrate>

0.08 wt% of amorphous spherical silica particles having an average particle diameter of 2.3 mu m and terephthalic acid as a dicarboxylic acid, ethylene glycol as a diol component, 2,2-dimethyl-1,3-propanediol, and 1,4-butanediol are 69.5, A blend of polyethylene terephthalate, polybutylene terephthalate, and 2.2-dimethyl-1,3-propanediol copolyester polyester composed of 23 and 7.5 molar ratios was dried, melted, and adhered to the cooling drum by an electrostatic method through an extrusion die. After making the amorphous unstretched sheet, apply the coating solution prepared using # 3 Mayer bar after the corona treatment, and then heat it in a tenter and perform transverse stretching 3.5 times in the direction perpendicular to the film's advancing direction at 80 ° C to obtain a 50 탆 thick film. Got it. The shrinkage rate in the stretching direction obtained at this time was 45%.

 <Example 1>

Laponite microparticles with surfactant and antistatic properties were added to the pure water passed through the ion exchange resin, stirred well to make a nanosol, and then a copolyester emulsion (Japan Synthetic, W0030) was added to give a total solid concentration of 2.0wt. A coating solution of% was prepared. The ratio of copolyester resin and laponite in the coating solution was set to a weight ratio of 1 to 2.

This coating solution was used to obtain a heat-shrink film coated by the above-described method, the physical properties thereof are shown in Table 1 below.

<Example 2>

It carried out by the same method as Example 1 except having prepared and used the mixed aqueous dispersion coating composition of 5.0% of total solid content, The physical property was evaluated and shown in following Table 1.

<Example 3>

Except for using Cloisite NA (manufactured by Southern clay) instead of laponite was carried out in the same manner as in Example 1, the physical properties thereof are shown in Table 1 below.

<Example 4>

Except for using Kunipia (Kunimine Industries, Ltd) instead of laponite was carried out in the same manner as in Example 1, the physical properties thereof are shown in Table 1 below.

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<Comparative Example 1>

The same procedure as in Example 1 was carried out except that the composition for mixing aqueous dispersion having a total solid content of 1.025% consisting solely of copolyester emulsion (Japanese Synthetic, W0030, Tg = 75 ° C.) was used and evaluated. It is shown in Table 1 below.

<Comparative Example 2>

A quaternary ammonium salt having surfactant and antistatic properties was added to the pure water passed through the ion exchange resin, stirred well, and dissolved. Then, a copolyester emulsion (Japan Synthetic, W0030) was added, and the total solid concentration was 2.0wt%. Phosphorus coating solution was prepared, and the mixture was prepared in the ratio of copolyester resin and quaternary ammonium salt in a ratio of 1 to 2 to obtain a heat-shrink film coated on the film obtained above. It was.

<Comparative Example 3>

Laponite microparticles with surfactant and antistatic properties were added to the pure water passed through the ion exchange resin, and then stirred well to form a nanosol, and then a copolyester emulsion containing sulfonate (Japan Synthetic, WR901) was added to the total solid. A coating solution having a concentration of 2.0 wt% was prepared, and the mixture was prepared in such a manner that the ratio of the copolymerized polyester resin and the laponite was in a weight ratio of 1 to 2. The physical properties of the coated film were shown in Table 1 below.

 TABLE 1

Surface resistance HAZE Coating uniformity Lacquer adhesion Water resistance Example 1 6.2 × 10 ⁹ 3.3 ○ 100 ○ Example 2 1.9 × 10 ⁸ 3.6 ○ 100 ○ Example 3 2.2 × 10 ¹¹ 3.5 ○ 100 ○ Example 4 9.7 × 10 ¹⁰ 3.7 ○ 100 ○ Comparative Example 1 4.2 × 10 ¹⁶ 3.1 ○ 100 ○ Comparative Example 2 3.6 × 10 ⁸ 3.8 ○ 0 Ⅹ Comparative Example 3 2.1 × 10 ¹⁰ 3.3 ○ 80 Ⅹ

As can be seen from the above examples and comparative examples, the heat-shrinkable polyester film according to the present invention coated with a coating liquid containing a specific amount of inorganic particles having antistatic properties is excellent in shrinkage characteristics as well as excellent antistatic properties in various containers. It is particularly suitable when used for labeling, whole coating, and the like.

Claims (4)

Laminated Silicate Inorganic Particles 20 Natural or Synthetic as Antistatic Agent, based on 100 parts by weight of a polyester-based water dispersion binder having a carboxylic acid in a main chain represented by the following formula (I) with a glass transition temperature of 67 ° C. or higher To prepare an antistatic aqueous dispersion containing 0.2 to 20% by weight of solids mixed in a ratio of ~ 1,000 parts by weight, A heat-shrink polyester film, which is prepared by applying and drying the antistatic aqueous dispersion on at least one surface of the base film in the heat-setting state during the stretching process or after the stretching of the base film. [Formula I]

[Wherein R is an aryl or an alkyl group, R ', R "is selected from an alkylene group represented by-(CH ₂ ) _n- , alkylene or polyoxyalkylene group having a side branch, ｘ, ｙ is 1 It is an integer between -100.] delete delete delete