Heat shrinkable film composition comprising polyethyleneterephtalate resin and polyester based copolymer, and heat shrinkable film

Abstract

A composition for forming a heat shrinkable film includes a polyethylene terephthalate (PET) resin having an inherent viscosity of 0.50 to 1.2 dl/g, and a polyester based copolymer including a dicarboxylic acid-derived residue including a residue derived from an aromatic dicarboxylic acid and a diol-derived residue including a residue derived from 4-(hydroxymethyl)cyclohexylmethyl 4′-(hydroxymethyl)cyclohexane carboxylate represented by the following Chemical Formula 1 and a residue derived from 4,4-(oxybis(methylene)bis)cyclohexane methanol represented by the following Chemical Formula 2. ##STR00001##

Claims

1. A heat shrinkable film, made by a method comprising: extruding a composition comprising: a polyethylene terephthalate (PET) resin having an inherent viscosity of 0.50 to 1.2dl/g; and a polyester based copolymer including a dicarboxylic acid-derived residue including a residue derived from an aromatic dicarboxylic acid; and a diol-derived residue including a residue derived from 4-(hydroxymethyl)cyclohexylmethyl 4′-(hydroxymethyl)cyclohexane carboxylate represented by the following Chemical Formula 1, a residue derived from 4,4-(oxybis(methylene)bis) cyclohexane methanol represented by the following Chemical Formula 2, and a residue derived from 1,4-cyclohexane dimethanol, to draw the extruded product, wherein the polyester based copolymer is prepared by reacting the dicarboxylic acid-derived residue and the diol-derived residue to perform an esterification reaction and a polycondensation reaction, wherein a total content of 4-(hydroxymethyl)cyclohexylmethyl 4′-(hydroxymethyl)cyclohexane carboxylate and the residue derived from 4,4-(oxybis(methylene)bis) cyclohexane methanol is 2 to 17 mol % of the entire diol, wherein the 4-(hydroxymethyl)cyclohexylmethyl 4′ (hydroxymethyl)cyclohexane carboxylate, the 4,4-(oxybis(methylene)bis) cyclohexane methanol, and the 1,4-cyclohexane dimethanol are present in an amount of 20 to 30 mol % relative to 100 mol % of the dicarboxylic acid, and wherein a temperature of a feeder of an extruder is lower than a temperature of a die, wherein the temperature of the die is between 270 and 275° C. ##STR00005##

Description

EXAMPLE 1

(1) A PET resin chip having an inherent viscosity of 0.80 dl/g and a polyester based copolymer chip of which an inherent viscosity was 0.75 dl/g and in which a content of cyclohexane dimethanol based compounds (4-(hydroxymethyl)cyclohexylmethyl 4′-(hydroxymethyl)cyclohexane carboxylate, 4,4-(oxybis(methylene)bis) cyclohexane methanol, and 1,4-cyclohexane dimethanol) in a polymer was 30 mol % based on a content of terephthalic acid were used as raw materials. After the resin chips were dried, the PET resin and the polyester based copolymer were mixed at a ratio of 1:9 in a rotary stirrer and put into a hopper of an injection machine. Then, a film was extruded using an extruder and closely adhered to a roll to obtain an undrawn film. Thereafter, the undrawn film was drawn, thereby preparing a heat shrinkable film.

EXAMPLE 2

(2) A heat shrinkable film was prepared by the same method in Example 1 except that the PET resin chip and the polyester based copolymer chip were blended at a ratio of 7:3.

EXAMPLE 3

(3) A heat shrinkable film was prepared by the same method in Example 1 except that the PET resin chip and the polyester based copolymer chip were blended at a ratio of 9:1.

EXAMPLE 4

(4) A heat shrinkable film was prepared by the same method in Example 1 except that a polyester based copolymer chip in which the content of the cyclohexane dimethanol compound was 20 mol % based on the content of terephthalic acid was used as the raw material and the PET resin chip and the polyester based copolymer chip were blended at a ratio of 1:9.

EXAMPLE 5

(5) A heat shrinkable film was prepared by the same method in Example 4 except that the PET resin chip and the polyester based copolymer chip were blended at a ratio of 4:6.

Comparative Example 1

(6) A heat shrinkable film was prepared by the same method as in Example 1 except that a polyester based copolymer chip including a 1,4-cyclohexane dimethanol monomer at a content of 30 mol % based on a content of terephthalic acid without including 4-(hydroxymethyl)cyclohexylmethyl 4′-(hydroxymethyl)cyclohexane carboxylate and 4,4-(oxybis(methylene)bis) cyclohexane methanol was used and the PET resin chip and the polyester based copolymer chip were blended at a ratio of 1:9.

Comparative Example 2

(7) A heat shrinkable film was prepared by the same method as in Example 1 except for using only a polyester based copolymer chip including a 1,4-cyclohexane dimethanol monomer at a content of 30 mol % based on a content of terephthalic acid without using the PET resin chip.

Comparative Example 3

(8) A heat shrinkable film was prepared by the same method as in Example 1 except for using only the PET resin chip without using the polyester based copolymer chip.

Experimental Example 1: Heat Shrinkage Rate

(9) After heat shrinkable films prepared in Examples and Comparative Examples were cut into a square (10 cmm×10 cmm) and drawn at a draw ratio (DR) of 1:5 or 1:6 (MD:TD) and a draw speed of 20 mm/sec., the films were put into an oven at a temperature shown in Table 1 for 40 seconds to thereby be heat-shrunk. Thereafter, lengths of the samples in horizontal and vertical directions were measured, and the heat shrinkage rates were calculated by the following Equation. The results were shown in the following Table 1.
Heat shrinkage rate (%)=100×(length before shrinkage−length after shrinkage)/(length before shrinkage)

(10) Experimental Example 2: Transmissivity (Transparency)

(11) Transmissivity (%) at a wavelength of 400 nm of the heat shrinkable films prepared in Examples and Comparative Examples was measured using a UV/Vis spectrophotometer (JASCO V530) and the results were shown in the following Table 1.

(12) TABLE-US-00001 TABLE 1 Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 1 Example 2 Example 3 Diol Monomer Mixture of Compounds of Mixture of Compounds of 1,4-Cyclohexane — Chemical Formulas 1 and 2 and Chemical Formulas 1 and 2 Dimethanol 30 mol % 1,4-Cyclohexane Dimethanol and 1,4-Cyclohexane (Cyclohexane Dimethanol Based Dimethanol (Cyclohexane compounds) 30 mol % Dimethanol Based compounds) 20 mol % Mixing Ratio 1:9 7:3 9:1 1:9 4:6 1:9 0:10 10:0 of PET:Polyester based copolymer Molding 255 255 255 255 255 255 265 260 Temperature (Feeder, ° C.) Molding 275 275 275 270 270 275 265 260 Temperature (Die, ° C.) Shrinkage 69 73 74 71 72 73 76 — Initiation Temperature (° C.) Heat 76 65 60 71 59 66 68 51 Shrinkage Rate (%) at 90° C. Heat 80 68 62 74 63 71 75 53 Shrinkage Rate (%) at 95~100° C. Transparency 88 85 83 87 84 86 89 78 (%)

(13) As shown in Table 1, the shrinkage rate and the shrinkage initiation temperature may be changed to the desired level by adjusting the mixing ratio of polyethylene terephthalate (PET) and the polyester based copolymer according to the present invention, and since the shrinkage rate was high and the shrinkage initiation temperature was low as compared to the cases of applying the polyester based copolymer in which the 1,4-cyclohexane dimethanol monomer that was generally widely used was included at a content of 30 mol % based on the content of terephthalic acid, the shrinkage speed was slow, such that a process may be smoothly controlled, thereby decreasing a defect rate. Therefore, a heat shrinkable film product having excellent moldability may be obtained by molding the composition for forming a heat shrinkable film as described above through an extruding and drawing process.

(14) Although the present invention has been described in detail based on particular features thereof, and it is obvious to those skilled in the art that these specific technologies are merely preferable embodiments and thus the scope of the present invention is not limited to the embodiments. Therefore, the substantial scope of the present invention is defined by the accompanying claims and equivalent thereof.