KR100555133B1 - Polyester resin compositions - Google Patents

Abstract

The present invention relates to a polyester resin composition excellent in mechanical strength and gas barrier properties, and more specifically, (a) with respect to 100 parts by weight of (a) polyester resin, (b)

0 to 20 parts by weight of plate silicate based on 100 parts by weight of a copolymer consisting of 50 to 99% by weight of a mixture of m -xylenediamine and adipic acid and 1 to 50% by weight of other monomers capable of forming polyamides in addition to the above monomers. It relates to a polyester resin composition composed of 0.1 to 30 parts by weight of a polyamide resin composition.

The composition according to the present invention is not only excellent in meltability and compatibility, but also excellent in mechanical strength and gas barrier property, and thus can be used in the manufacture of films, sheets, containers, and the like.

Polyester, m-xylenediamine, adipic acid, plate silicates, ε-caprolactam, gas barrier properties

Description

Polyester resin compositions

The present invention relates to a novel polyester resin composition, and more particularly to a polyester resin, by combining a polyamide copolymer prepared from a mixture of monomers capable of forming a polyamide and a plate-like silicate, The present invention relates to a polyester resin composition having improved gas barrier properties.

Polyester resins are widely used in food and beverage industry films and containers because of their excellent mechanical strength, chemical resistance, moldability and gas barrier properties.

However, polyester resins have limited gas barrier properties, such as tomato-containing products (ketchup, tomato sauce), juices (fruit and vegetable juices), alcoholic carbonated drinks (beer, malt beverages, champagne), and beverages for warming up (coffee, tea). Its use is limited in fields that require high gas barrier properties such as).

In order to improve this, a method of preparing a polyester resin in a multilayer structure with a polymer having excellent gas barrier properties, or treating the surface of a container by chemical or physical methods such as plasma coating has been proposed.

However, this method is expensive and can cause problems of recycling.

Another way to improve the gas barrier properties of polyester resins is to mix polyamides known as MXD-6.

This method has the advantage of being cost-competitive and using existing equipment without raising the issue of recycling.

For this reason, MXD-6 polyamide resins, that is, resins prepared from m -xylenediamine and adipic acid, have excellent barrier properties to gases such as oxygen, carbon dioxide, and water vapor, and thus are widely used for packaging films and multilayer containers.

In addition, the MXD-6 polyamide resin is a resin suitable for use in combination with a polyester resin because it has excellent compatibility with the polyester resin, and the glass transition temperature, melting point, and crystallization rate are similar to the polyester resin.

However, since the phenylene structure present in the main chain gives rigid properties to the MXD-6 polyamide resin, when combined with the polyester resin, the phenylene structure lowers the degree of flexibility and elongation to reduce the degree of orientation, thereby lowering the mechanical strength.

The present invention is to solve the above problems of the prior art, and to provide a polyester resin composition excellent in mechanical strength and gas barrier properties as well as excellent compatibility between the polyester resin and the polyamide copolymer. do.

Another object of the present invention is to provide a film, a sheet and a container including at least one layer of the polyester resin composition layer.

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

The present invention relates to 100 parts by weight of (a) polyester resin, (b) 50 to 99% by weight of a mixture of m -xylenediamine and adipic acid, and 1 to 50% by weight of a monomer capable of forming a polyamide in addition to the above monomers. It relates to a polyester resin composition, characterized in that the composition is composed of 0.1 to 30 parts by weight of a polyamide resin composition composed of 0 to 20 parts by weight of plate-like silicate with respect to 100 parts by weight of a copolymer composed of.

In the present invention, the polyester resin is one or more selected from the group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, or copolymers thereof, and more preferably. Polyethylene terephthalate.

In the present invention, m -xylenediamine and adipic acid forming the MXD-6 portion of the polyamide copolymer are used in a molar ratio of 1: 1 and added to the monomer mixture at 50 to 99% by weight.

When the amount of the mixture of m -xylenediamine and adipic acid is less than 50% with respect to the entire monomer mixture, compatibility with the polyester resin is lowered, thereby decreasing mechanical strength and gas barrier property.

Other monomers capable of forming polyamides include ε-caprolactam, terephthalic acid, isophthalic acid, 12-aminododecanoic acid, tetramethylenediamine, and hexamethylenediamine. 1 to 50% by weight of the mixture is used for mixing.

However, the polyamide copolymer has a disadvantage in that the crystallization rate is slow and the crystallinity is reduced, thereby deteriorating physical properties such as heat resistance, mechanical strength, and gas barrier properties.

In the present invention, the plate-like silicate improves the heat resistance, chemical resistance, mechanical strength, gas barrier property, etc. of the polyamide copolymer, and also serves to promote the slow crystallization rate by copolymerization.

The plate silicates include montmorillonite, hectorite, Weidelite, saponite, nontronite, mica, fluorinated mica and the like, and at least one of them is used, more preferably montmorillonite.

The plate silicate is used in an amount of 0 to 20 parts by weight based on 100 parts by weight of the polyamide copolymer, and when it exceeds 20 parts by weight, the melt viscosity of the polymer is increased by the plate silicate having a large surface area, thereby making it difficult to polymerize and process.

In the present invention, the plate-like silicate may be one having an interlayer distance of 10 as it is without surface treatment, or an enlarged interlayer distance using a surface treatment agent.

Surface treatment agents used to extend the interlayer distance include ε-caprolactam, phosphoric acid, 6-aminododecanoic acid, 12-aminododecanoic acid, alkyl amines, alkyl ammonium ions, silane compounds and the like.

In the case of surface treatment of the plate silicate, the plate silicate is reacted with ε-caprolactam, a surface treatment agent and water in the preparation to perform pretreatment, which is then transferred to a reactor to prepare a polyamide copolymer.

This surface treatment method does not require a recovery process of the plate silicate, there is an advantage that can significantly reduce the amount of water used as the dispersion medium of the plate silicate.

The polymerization process for preparing the polyamide copolymer in the present invention is as follows.

(1) A plate-like silicate, ε-caprolactam, a surface treatment agent, and water are added to the preparation, followed by heating while stirring to perform pretreatment.

At this time, the surface treating agent is added in the amount of 1 equivalent to the ion exchange ability of the plate silicate.

(2) In the reactor, monomers forming m -xylenediamine, adipic acid, and other polyamides are added at a desired composition ratio, and water is added and stirred.

If the plated silicate is not surface treated or if a surface treated commercialized product is used, the plated silicate is added directly to the reactor.

(3) After transferring the mixture of the preparation to the reactor and reacting in the pressurized state, the pressure of the reactor is gradually removed to make the atmospheric pressure.

(4) Pressure reduction is carried out to adjust the molecular weight of the copolymer to the desired level, and then discharged.

(5) The unreacted material of the copolymer is extracted and then dried to obtain the final polyamide copolymer.

In the present invention, the polyester resin and the polyamide copolymer may be manufactured into a molding by using an injection machine or an extruder after dry blending or melt blending according to the production conditions of the product. Equipment such as a tumbler mixer is used, and melt mixing is carried out using a Brabender mixer, a single- or twin-screw extruder.

The polyamide copolymer is used in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the polyester resin, and when it is less than 0.1 parts by weight, it is difficult to obtain the desired effect of the present invention. Will decrease.

In addition to the above components, a mold release agent, a colorant, an antioxidant, and a flame retardant may be added to the polyester resin composition of the present invention as needed.

The evaluation method of the physical property used in the Example and the comparative example is as follows.

<Property evaluation method>

1) Melting point and crystallization temperature: Measured by differential scanning thermal analyzer (DSC).

2) Density: measured by ASTM D 1505, unit is g / cm 3.

3) Intrinsic viscosity: After dissolving in a co-solvent of 1,1,2,2-tetrachloroethane and phenol, it measured at the temperature of 25.

4) Tensile strength and tensile modulus of elasticity: According to ASTM 882, the width of the specimen was 15 mm, the gauge length was 50 mm, and then measured at a rate of 50 mm / min.

At this time, the measurement temperature was 23 degreeC and the relative humidity was maintained at 55%.

5) Oxygen Permeability: The biaxially stretched film was placed on an oxygen permeability measuring device (Mocon Ox-Tran 2/20), and then measured at a temperature of 23 ° C. for 24 hours.

The relative humidity of oxygen and carrier gas (98% nitrogen + 2% hydrogen) was maintained at 55%.

Examples 1 to 3

3 kg of ε-caprolactam, 48.2 kg of m -xylenediamine, 51.3 kg of adipic acid and 55 kg of water were added thereto, followed by stirring at 130 rpm for 2 hours at 50 rpm.

The temperature of the reactor was raised to 265 to maintain a pressure of 14 kg / cm 2 and reacted at 40 rpm for 2 hours.

After the pressure of the reactor was gradually removed for 1 hour to create an atmospheric pressure, the reaction was completed by depressurizing for 210 minutes at a pressure of 0.3 kg / cm 2.

After the completion of the polymerization, the polymer was discharged by pressurizing at 5 kg / cm 2, and then, it was made into chips. The polymer was washed with water at 95 for 24 hours to remove the unreacted material, and then vacuum dried at 100 to 20 hours to obtain a polyamide copolymer resin. .

After the polyester resin and the polyamide copolymer resin were dry mixed at the weight% shown in Table 1 below, the mixture was mixed using a single screw extruder having an L / D of 25 to 220-260-280-285-280-280-280 A 150 m sheet was made by melt extrusion at -280-270-262-262-262 (° C).

The thermal analysis of the sheet produced using a differential scanning thermal analyzer was performed, the density and intrinsic viscosity were measured and the results are shown in Table 1.

The prepared sheet was cut to a size of 9 cm × cm and preheated at 120 to 30 seconds in a biaxial stretching apparatus, and then simultaneously stretched 3.4 times in biaxial directions, respectively, and heat-set at 200 ° C. for 30 seconds to prepare a biaxially stretched film.

Thermal analysis of the biaxially oriented film prepared by using a differential scanning thermal analyzer was performed, and the tensile strength, tensile modulus and oxygen permeability were measured and the results are shown in Table 2.

Examples 4-6

10 kg of ε-caprolactam, 43.9 kg of m -xylenediamine, and 46.6 kg of adipic acid were added, followed by adding 2 kg of montmorillonite (Closisite 15A, 125meq / 100g) and 55 kg of water to Examples 1 to 3 Polyamide copolymer resin was prepared in the same manner.

After the polyester resin and the polyamide copolymer resin were dry mixed in the weight% shown in Table 1, the sheet and the biaxially oriented film were prepared in the same manner as in Examples 1 to 3, and then the physical properties were evaluated. 2 is shown.

Comparative Example 1

The polyester resin was melt-extruded at 220-260-280-285-280- 280-280-280-270-262-262-262 (℃) using a single screw extruder having a L / D of 25 to give Examples 1 to 3. After the sheet and the biaxially stretched film was prepared in the same manner as in the following, the physical properties were evaluated and the results are shown in Tables 1 and 2.

Comparative Example 2

After the polyester resin and MXD-6 (Mitsubishi Gas Chemical Co., Ltd. 6007) resin were dry mixed at the weight% shown in Table 1, the sheet and the biaxially stretched film were prepared in the same manner as in Examples 1 to 3, and then the physical properties were evaluated. The results are shown in Tables 1 and 2.

<Table 1>

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Polyester resin (% by weight) 98 95 90 98 95 90 100 95 Polyamide Copolymer Resin (wt%)  2  5  10  2  5  10  -  5 (MXD-6) Melting Point (℃) 255 219 255 219 255 255 206 255 205 255 254 234 255 Crystallization temperature (℃) 198 167 205 167 205 198 148 205 147 209 196 182 204 Density (g / cm 3) 1.34 1.32 1.32 1.34 1.32 1.30 1.34 1.32 Intrinsic viscosity (dl / g) 0.59 0.54 0.53 0.59 0.56 0.52 0.60 0.55

<Table 2>

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Polyester resin (% by weight) 98 95 90 98 95 90 100 95 Polyamide Copolymer Resin (wt%)  2  5  10  2  5  10  -  5 (MXD-6) Melting Point (℃) 253 218 254 217 255 253 202 255 205 254 255 227 254 Crystallization temperature (℃) 209 165 209 164 211 204 210 151 211 202 175 212 Tensile Strength (MPa) 234 249 245 286 292 269 242 232 Tensile Modulus (MPa)) 3,720 4,070 3,870 3,940 4,230 3,960 3,580 3,460 Oxygen permeability (cc / ㎡ day) 98 84 67 93 80 56 133 87

As can be seen from the above examples and comparative examples, mechanical strength and gas barrier by using a combination of polyamide copolymers prepared from a mixture of monomers capable of forming polyamides and plate silicates with respect to polyester resins It is possible to prepare a polyester resin composition having excellent properties and improved crystallization rate.

Therefore, the polyester resin composition according to the present invention is useful as a material for sheets, films, containers, and the like that require excellent mechanical strength and gas barrier properties.

Moreover, the polyester resin composition which concerns on this invention can be utilized as a material of the various films, sheets, or container which contains the said polyester resin composition at least one or more layers.

Claims (5)

(A) To 100 parts by weight of polyester resin, (b) from 50 to 99% by weight of a mixture of m -xylenediamine and adipic acid, and from 1 to 50% by weight of other monomers capable of forming a polyamide in addition to the above monomers. A polyester resin composition comprising 0.1 to 30 parts by weight of a polyamide resin composition composed of 0 to 20 parts by weight of plate silicates, based on 100 parts by weight of the copolymer. According to claim 1, wherein the polyester resin is at least one member selected from the group consisting of polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, or copolymers thereof. Ester resin composition. The other monomer capable of forming a polyamide is at least one member selected from the group consisting of ε-caprolactam, terephthalic acid, isophthalic acid, 12-aminododecanoic acid, tetramethylenediamine, and hexamethylenediamine. Polyester resin composition, characterized in that. The polyester resin composition according to claim 1, wherein the plate silicate is at least one member selected from the group consisting of montmorillonite, hectorite, bidelite, saponite, nontronite, mica, and fluorinated mica. 2. The platelet silicate is untreated or surface treated with ε-caprolactam, phosphoric acid, 6-aminododecanoic acid, 12-aminododecanoic acid, alkyl amines, alkyl ammonium ions, silane compounds. Polyester resin composition, characterized in that.