KR102116507B1 - Polyester Resin Composition and Molded Article Produced with the Same - Google Patents

Abstract

The present invention relates to a polyester resin composition and a molded article prepared therefrom, and more specifically, includes 20 to 60% by weight of polybutylene terephthalate resin (PBT) and 40 to 80% by weight of polycarbonate resin (PC). 100 parts by weight of the basic resin;
10 to 20 parts by weight of a compound containing maleic anhydride relative to 100 parts by weight of the base resin; And it relates to a polyester resin composition comprising 1 to 3 parts by weight of a carbodiimide compound and a molded article prepared therefrom.

Description

Polyester resin composition and molded article produced therefrom {Polyester Resin Composition and Molded Article Produced with the Same}

The present invention relates to a polyester resin composition for use in safety toe caps and safety helmets and molded articles made therefrom.

The present invention relates to a polyester resin composition that simultaneously satisfies high impact strength and high flexural modulus and maintains properties even in a high temperature and high humidity environment, and more specifically, polybutylene terephthalate resin, polycarbonate resin, impact modifier and moisture resistance It relates to a polyester composition consisting of a release.

The toe cap of the safety shoes is a means to protect the foot from external impact by being located between the inner skin and the outer part of the toe of the shoe that requires safety during work. In general, the toe cap is made of a metal material, but this adds to the weight of the shoe and has the disadvantage of being vulnerable to thermal insulation when the working environment is low.

In addition, the conventional plastic tow cap has advantages such as being lightweight and providing resilience, but it needs to be supplemented because it has a fatal disadvantage in that its impact resistance is weaker than that of a metal tow cap. In addition, in the case of safety shoes, because of its own functionality, it is poorly ventilated compared to general sneakers, and when exposed to a humid environment for a long period of time, the vulnerable polyester resin has an unsuitable problem.

In the case of polycarbonate-polybutylene terephthalate alloy resin compositions used as a conventional material, there is a tendency to bend characteristics (resilience) and impact resistance according to the content ratio of polycarbonate and polybutylene terephthalate, so safety toe As a resin composition to be used as a cap, a composition capable of simultaneously satisfying the above two characteristics must be developed, and a situation is required to develop a resin composition having special performance capable of maintaining mechanical properties even when exposed to moisture for a long time.

The present invention seeks to provide a polyester resin composition having excellent impact resistance, flexural modulus and hydrolysis resistance, and a molded article prepared therefrom.

Accordingly, the present invention is a preferred first embodiment, a basic resin comprising 100 parts by weight of a basic resin comprising 20 to 60% by weight of polybutylene terephthalate resin (PBT) and 40 to 80% by weight of polycarbonate resin (PC). Parts by weight; 10 to 20 parts by weight of a compound containing maleic anhydride, based on 100 parts by weight of the base resin; And 1 to 3 parts by weight of an imide-based hydrolysis agent selected from aromatic carbodiimide, aliphatic carbodiimide, and mixtures thereof.

The aliphatic carbodiimide according to the above embodiment may be poly (1,3,5-triisopropyl-phenylene-2,4-carbodiimide).

The compound containing maleic anhydride according to the embodiment may be represented by Formula 1 below.

[Formula 1]

Here, m, n and p are integers of 10 to 50, respectively.

The polyester resin composition according to the embodiment may further include an additive selected from heat stabilizers, mold release agents, antioxidants, and mixtures thereof.

The present invention also provides, as a second preferred embodiment, a molded article made from the polyester resin composition.

The polyester resin composition according to the present invention has excellent impact resistance, flexural modulus, and hydrolysis resistance, and is particularly useful for toe caps and safety helmets for safety boots.

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

The present invention is 100 parts by weight of a base resin comprising 20 to 60% by weight of polybutylene terephthalate resin (PBT) and 40 to 80% by weight of polycarbonate resin (PC); 10 to 20 parts by weight of a compound containing maleic anhydride represented by Chemical Formula 1 with respect to 100 parts by weight of the basic resin; And it relates to a polyester resin composition comprising 1 to 3 parts by weight of a carbodiimide compound.

[Formula 1]

Here, m and n are integers of 10 to 50, respectively.

1) Basic balance

The basic resin according to the present invention may be one containing 20 to 60% by weight of polybutylene terephthalate (PBT) resin and 40 to 80% by weight of polycarbonate (PC) resin.

Polybutylene terephthalate (PBT) resin

Polybutylene terephthalate resin is a resin produced by a polycondensation reaction of 1,4-butanediol and dimethyl terephthalate, and is a crystalline thermoplastic plastic resin having a melting point of 225 ° C.

The polybutylene terephthalate resin may have an intrinsic viscosity of 0.6 dl / g to 1.8 dl / g, and if the intrinsic viscosity of the polybutylene terephthalate resin is less than 0.6 dl / g, mechanical properties may deteriorate, and 1.8 dl If it exceeds / g, flowability may deteriorate.

In this case, the intrinsic viscosity (η) can be measured at 20 ° C. by using the Uberode-type viscosity tube of the filtrate obtained after dissolving the sample to be measured in methylene chloride.

The polybutylene terephthalate resin is to be contained in 20 to 60% by weight of the base resin, if the content is less than 20% by weight, the effect of improving the flexural modulus may be negligible, and if it exceeds 60% by weight, the impact strength may be limited. Can be.

Polycarbonate (PC) resin

Polycarbonate (PC) resin is an aromatic polycarbonate resin produced by an interfacial polycondensation reaction between bisphenol A and phosgene, and may have a viscosity average molecular weight (Mv) of 15,000 to 35,000, and an impact when the viscosity average molecular weight is less than 15,000. The strength may be lowered, and if it is more than 35,000, the flowability may be lowered.

At this time, the viscosity-average molecular weight was measured by dissolving polycarbonate pellets in methylene chloride and measuring the intrinsic viscosity [η] of the mixed filtrate at 20 ° C using the Uberode-type viscosity tube. Equation of '.

[η] = 1.23 X 10 ^ (-5) X Mv ^ (0.83)

The content of the polycarbonate resin may be 40 to 80% by weight of the base resin, if the content is less than 40% by weight, the effect of improving impact properties may be negligible, and if it exceeds 80% by weight, fluidity may be deteriorated.

2) Compound containing maleic anhydride (impact reinforcement)

The compound containing maleic anhydride according to the present invention serves as an impact resistance agent, and has excellent compatibility with a polyester resin.

In addition, the compound containing maleic anhydride may improve the continuous sagging phenomenon of the extrudate during extrusion by increasing the viscosity of the polyester resin composition to impart a viscosity for the basic extrusion moldability of the polyester resin composition. In addition, it is possible to reinforce the impact strength of the polyester resin composition.

The content of the compound containing maleic anhydride may be 10 to 20 parts by weight based on 100 parts by weight of the polyester resin, and if the content is less than 10 parts by weight, the effect of improving mechanical strength is negligible, and more than 20 parts by weight It can only lead to a cost increase without an improvement in strength.

The compound containing maleic anhydride may be selected in consideration of reactivity with a polyester end group, compatibility with a polyester resin, and viscosity properties suitable for extrusion molding, and the compound containing maleic anhydride is represented by the following Chemical Formula 1 It may be a compound represented by.

[Formula 1]

Here, m, n and p are integers of 10 to 50, respectively.

More specifically, the compound containing maleic anhydride may be a copolymer in which maleic anhydride functional groups are grafted onto polyethylene octene.

3) Carbodiimide compound (hydrolysis-resistant agent)

The carbodiimide compound of the present invention is an imide-based hydrolysis agent, and serves to inhibit hydrolysis between polybutylene terephthalate molecules, and the content of the carbodiimide compound is 1 to 3 weight based on 100 parts by weight of the base resin If the content is less than 1 part by weight, the effect of hydrolysis resistance may be negligible, and if the content is more than 3 parts by weight, the cost may be increased without improvement of hydrolysis resistance.

The imide-based hydrolysis agent may be selected from aromatic carbodiimide, aliphatic carbodiimide, and mixtures thereof, and the aliphatic carbodiimide is poly (1,3,5-triisopropyl-phenylene-2, 4-carbodiimide).

In addition, the polyester resin composition of the present invention may further include an additive according to required properties, and the additive may be selected from heat stabilizers, mold release agents, antioxidants, and mixtures thereof.

The antioxidant may be selected from phenol, phosphite, thioether and amine types.

The release agent may be one selected from fluorine-containing polymers, silicone oils, metal stearic acid salts, metal montanic acid salts, montanic acid ester waxes, and polyethylene waxes.

Briefly summarized, the polyester resin composition according to the present invention may be made of a basic resin comprising an polybutylene terephthalate resin and a polycarbonate resin, an imide-based hydrolysis agent and an imide-based hydrolysis agent, and the composition It satisfies both the impact characteristics and the flexural modulus at the same time, and is characterized by excellent hydrolysis resistance. Specifically, the impact strength is 700 to 730 J / m (ASTM 256, 5.5J), and the flexural modulus is 22,000 to 25,000 kgf / ㎠ ( ASTM 790), and may be one that maintains 90% physical properties compared to initial properties at PCT (Pressure Cooker Test) 168h. In particular, the polyester resin composition according to the present invention can be applied to safety boots toe caps and safety helmets.

Hereinafter, the configuration and effects of the invention will be described in more detail through specific examples and comparative examples to help understanding of the invention. However, the following examples are only for understanding the invention more clearly, and the invention is not limited to the following examples.

Examples 1-4 and Comparative Examples 1-5

Each component was melted and kneaded in a twin-screw extruder heated to 245 to 270 ° C according to the composition shown in Table 1 below, to prepare a polyester resin composition in a chip state, and dehumidified at 120 ° C for 5 hours. It was dried using a dryer.

The polyester resin compositions prepared in Examples and Comparative Examples were evaluated by using a heated screw-type injection machine to prepare respective specimens at the same temperature as when melting and kneading.

Specifically, flexural strength, impact strength, tensile strength, and melt index were evaluated in the following manner using specimens prepared using the polyester resin compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 4, Table 2 shows the results.

In addition, for the specimens prepared using the polyester resin composition prepared in Example 4 and Comparative Example 5, PCT (Pressure Cooker Test) evaluation was performed in the following manner, but impact at 0 hr, 48 hr, 96 hr, and 168 hr. Strength and flexural modulus were evaluated.

1. Flexural strength: A 1/8 inch specimen was prepared according to ASTM D790, and the flexural strength measurement speed was set to 10 mm / min.

2. Impact strength: A 1/4 inch specimen was prepared according to ASTM D256 to measure the impact strength of Izod Notched at room temperature (23 ° C).

3. Tensile strength: A 1/8 inch specimen was prepared according to ASTM D638, and the tensile strength measurement rate was set to 50 mm / min.

4. Melt Index: Measured under a load of 2.16 kg at 250 ° C. according to ASTM D1238.

5. PCT (Pressure Cooker Test): This is a method designed to evaluate the phenomenon that can occur when plastics are exposed to moisture for a long time. Put the specimen in a pressure cooker at 121 ° C and 2 atmospheres, and boil it with water vapor to observe changes in physical properties. Is how to do it.

division Basic resin (based on 100 parts by weight) Impact modifier
(Parts by weight) Hydrolysis agent
(Parts by weight) PBT
(weight%) PC
(weight%) Example 1 30 70 15 2 Example 2 20 80 15 2 Example 3 60 40 15 2 Example 4 30 70 10 2 Comparative Example 1 30 70 0 2 Comparative Example 2 30 70 30 2 Comparative Example 3 10 90 15 2 Comparative Example 4 70 30 15 2 Comparative Example 5 30 70 10 0

* PBT: Kolon Corporation

* PC: manufactured by LG Chem

* Impact modifier (compound containing maleic anhydride): manufactured by Dupont (Elvaloy PTW resin)

* Hydrolysis resistance (carbodiimide compound): manufactured by Raschig (Stabilizer 9000)

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Impact strength
(J / m) 708 700 744 59 700 632 750 Flexural strength
(Kgf / ㎠) 943 930 918 923 364 973 721 Flexural modulus
(Kgf / ㎠) 23885 24924 22290 24786 23726 24071 19386 The tensile strength
(Kgf / ㎠) 511 523 499 565 529 549 462 Flow index
(g / 10min) 14.3 9.8 21.0 19.1 5.8 5.3 24.6

division Example 4 Comparative Example 5 0 h Impact strength
(J / m) 712 716 Flexural modulus
(Kgf / ㎠) 22465 22942 48 h Impact strength
(J / m) 710 691 Flexural modulus
(Kgf / ㎠) 22001 18752 96 h Impact strength
(J / m) 700 542 Flexural modulus
(Kgf / ㎠) 21757 17548 168 h Impact strength
(J / m) 677 <100 Flexural modulus
(Kgf / ㎠) 20066 <12000

Referring to Table 2, in the composition carried out in Example 1, compared with Comparative Example 1, the impact strength is very excellent, and shows a similar level compared to Comparative Example 2. However, in the case of Comparative Example 2, the flow index is very low, and thus there is a problem in productivity during actual product molding. In addition, Comparative Example 3 has excellent flexural modulus compared to Example 1, but has low impact characteristics, and Comparative Example 4 has excellent impact characteristics compared to Example 1, but it can be confirmed that the flexural modulus is low. In addition, Examples 3 and 4 satisfy the above-mentioned preferred impact strength and flexural strength. In the case of safety toe caps or helmets, the impact strength and flexural modulus should be satisfied at the same time. Therefore, as a result of Example 1 and Example 3 and Comparative Examples 1 to 4, it can be confirmed that the composition within the range specified in the present invention satisfies the two properties at the same time.

Referring to Table 3, PCT (Pressure Cooker Test) evaluation results, the composition of Example 4 shows a physical properties of 95% or more compared to the initial physical properties after 168 hours, but the composition of Comparative Example 5 without the hydrolysis-resistant carbodiimide compound After 96 hours, it was confirmed that it showed 75% of the properties compared to the initial properties.

Claims (6)

100 parts by weight of a basic resin comprising 20 to 60% by weight of polybutylene terephthalate resin (PBT) and 40 to 80% by weight of polycarbonate resin (PC);
With respect to 100 parts by weight of the basic resin
10 to 20 parts by weight of a compound containing maleic anhydride; And
A polyester resin composition comprising 1 to 3 parts by weight of a carbodiimide compound. According to claim 1,
The polybutylene terephthalate resin has an intrinsic viscosity of 0.6 to 1.8 dl / g,
The polycarbonate resin is a polyester resin composition, characterized in that the viscosity average molecular weight (Mv) is 15,000 to 35,000. According to claim 1,
The carbodiimide compound is a polyester resin composition characterized in that it is selected from aromatic carbodiimide, aliphatic carbodiimide, and mixtures thereof. According to claim 1,
The polyester resin composition, characterized in that the compound containing maleic anhydride is represented by the following formula (1).
[Formula 1]

Here, m, n, and p are integers of 10 to 50, respectively. According to claim 1,
The polyester resin composition is a polyester resin composition characterized in that it further comprises an additive selected from heat stabilizers, mold release agents, antioxidants and mixtures thereof. A molded article made from the polyester resin composition according to any one of claims 1 to 5.