KR20160083528A - Polyester resin composition, and molded artice manufactured therefrom - Google Patents

Abstract

The present invention relates to a polyester resin composition, comprising: 100 parts by weight of a base resin including a polybutylene terephthalate resin (PBT) and a polyethylene terephthalate (PET); 90-120 parts by weight of a glass fiber with respect to 100 parts by weight of the base resin; and 0.1-2 parts by weight of a silane compound. The polyester resin composition can exhibit weather resistance stability, surface properties, size stability, and mechanical properties, required for a wiper blade component of a vehicle.

Description

POLYESTER RESIN COMPOSITION AND POLYESTER RESIN COMPOSITION AND MOLDED ARTICE MANUFACTURED THEREFORM

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin composition and a plastic molding using the same. More specifically, the present invention relates to a polybutylene terephthalate (PBT) resin, a polyethylene terephthalate (PET), a glass fiber, ≪ / RTI > compounds.

Wiper blade parts for automobiles are generally made of metal for high strength, mold shrinkage and weather resistance. Recently, there has been a tendency for wiper blade parts to be made lighter and more environmentally friendly, and polybutylene terephthalate resin (PBT) and polyethylene terephthalate resin And glass fiber reinforced materials. However, in the case of conventional PBT and PET reinforced materials, a resin having a high metal or physical property is contained in the blades to produce inserts for injection molding in order to exhibit specific properties. Manufacture of plastic wiper blades without metal or padding requires high physical properties and low mold shrinkage, which can lead to cost reduction and process simplification.

In addition, wiper blades are unpainted products and require excellent appearance and weatherability. In order to bring the physical properties and shrinkage to desired levels, it is most preferable to increase the specific gravity of the glass fibers in the resin composition. However, Is limited. As the content of the glass fiber increases continuously, the mechanical properties are increased, but the load is increased during compounding, resulting in a decrease in productivity, and the flowability is rapidly lowered, And the surface characteristics are also lowered.

Therefore, it is possible to further increase the mechanical properties within a limited amount of the glass fiber, and to use the wiper blade, it is possible to provide a resin capable of significantly improving mechanical properties such as excellent surface properties and weatherability, Development of a composition is required.

Accordingly, it is an object of the present invention to provide a molded article satisfying impact resistance, stability, surface characteristics and shrinkage characteristics by producing a polyester resin containing PBT resin, PET resin, glass fiber, and silane compound.

A first preferred embodiment according to the present invention is a resin composition comprising 100 parts by weight of a base resin comprising polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) And 0.1 to 2 parts by weight of a silane compound, wherein the weight ratio of the PBT to the PET is 60:40 to 90:10.

The intrinsic viscosity of the PBT resin according to the first embodiment may be 0.7 to 1.2 dl / g.

The intrinsic viscosity of the PET resin according to the first embodiment may be 0.6 to 1.2 dl / g.

The silane compound according to the first embodiment may be at least one selected from the group consisting of 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane , And the like.

The glass fiber according to the first embodiment may have a diameter of 10 to 13 탆, a length of 3 to 5 mm, and a surface treated with a coupling agent.

In this case, the coupling agent may be a silane-based material having one kind of organic functional group selected from the group consisting of a vinyl group, an epoxy group, a mercaptan group, and an amine group.

A second preferred embodiment according to the present invention is a plastic molded article comprising the polyester resin composition.

The molded article according to the second embodiment has a tensile strength of 1500 kgf / cm ² or more and a flexural modulus of 120,000 kgf / cm ² or more.

According to the present invention, it is possible to obtain excellent mechanical properties and surface properties by using a base resin including PBT and PET and glass fiber, and to improve the reactivity between the base resin and the glass fiber, Thereby increasing the compatibility. Furthermore, the polyester molded articles produced using the same can exhibit excellent mechanical properties, surface properties, weatherability, and dimensional stability, and can be used as automobile wiper blade materials.

According to one aspect of the present invention, there is provided a thermoplastic resin composition comprising 90 to 120 parts by weight of glass fiber (Glassfiber) per 100 parts by weight of a base resin comprising polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) And 0.1 to 2 parts by weight of a silane compound, wherein the weight ratio of the PBT to the PET is 60:40 to 90:10. In addition, a plastic molded article containing the polyester resin composition can be provided.

In the present invention, by using a polyester including PBT and PET, it is possible to obtain excellent surface characteristics and processing characteristics of a molded article made of the polyester resin of the present invention, and has high mechanical properties including glass fibers. Further, the reactivity of the PBT and the PET including the silane compound is improved to increase the compatibility.

The silane compound is represented by the following formula (1).

≪ Formula 1 >

[Basic Resin]

In the present invention, the base resin may include polybutylene terephthalate (PBT) and polyethyleneterephthalate (PET), and the weight ratio of the PBT to PET is 60:40 to 90: 10 < / RTI >

[ PBT  Suzy]

The polybutylene terephthalate (PBT) resin can be produced by condensation polymerization through direct esterification reaction or transesterification reaction using butanediol and terephthalic acid or dimethyl terephthalate as monomers.

The PBT resin may have an intrinsic viscosity of 0.7 to 1.2 dl / g. When the intrinsic viscosity of the PBT resin is less than 0.7 dl / g, the overall mechanical properties of the resin composition may deteriorate and flowability may be increased. If it is more than 1.2 dl / g, processing due to decrease in flowability during injection molding may be difficult due to high viscosity.

In this case, the intrinsic viscosity (?) Can be measured at 20 占 폚 using a Ureter-type viscosity tube after the sample to be measured is dissolved in methylene chloride.

If the content of the PBT resin is less than 60% by weight, the mechanical properties may be deteriorated. If the content of the PBT resin is more than 90% by weight, the PBT resin may be crystallized rapidly The dimensional stability may be deteriorated.

[ PET  Suzy]

The polyethylene terephthalate (PET) resin can be produced by condensation polymerization through direct esterification reaction or transesterification reaction using ethylene glycol and terephthalic acid or dimethyl terephthalate as monomers.

If the intrinsic viscosity of the PET resin is less than 0.6 dl / g, the overall mechanical property of the resin composition may be deteriorated and flowability may be increased. If the intrinsic viscosity of the PET resin is less than 0.6 dl / g, If it is more than 1.2 dl / g, processing due to decrease in flowability during injection molding may be difficult due to high viscosity.

If the content of the PET resin is less than 10% by weight, the surface properties are not improved. If the content of the PET resin is more than 40% by weight, the PET resin may have a slow crystallization , Which may result in a decrease in the surface properties due to a decrease in the overall crystallization temperature.

[glass fiber]

In the present invention, it is preferable to use glass fibers having a diameter of 10 to 13 mu m and a length of 3 to 5 mm and having a surface treated with a coupling agent. The coupling agent is preferably a silane-based material having an organic functional group such as a vinyl group, an epoxy group, a mercaptan group or an amine group. The glass fiber can serve to reinforce the mechanical properties, particularly the mechanical strength, of the polyester resin composition and the plastic molded article obtained therefrom. If the content of the glass fiber is less than 90 parts by weight, the target value of the mechanical properties can not be attained. If the amount of the glass fiber exceeds 120 parts by weight, the mechanical properties But may cause defective molding due to a decrease in surface characteristics and a decrease in flowability.

[ Silane  compound]

In the present invention, the silane compound has the same structure as the chemical formula (1), and the compatibility between the glass fiber and the polymer is increased to improve the mechanical properties and surface properties. The present silane compound is a substance which simultaneously contains an epoxy group and a silane group in the molecule and specifically includes 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4- Hexyl) ethyltrimethoxysilane and the like, and it is preferable to use 3-glycidoxypropyltrimethoxysilane. The amount of the silane compound may be 0.1 to 2 parts by weight based on 100 parts by weight of the base resin. If the amount is less than 0.1 part by weight, the effect of improving mechanical strength is insufficient. If the amount is more than 2 parts by weight, .

[additive]

The polyester resin composition according to the present invention may further contain additives according to the required characteristics.

The additive may be at least one selected from the group consisting of heat stabilizers, antioxidants, light stabilizers, weather stabilizers, mold release agents, compatibilizers, dyes, pigments, colorants, nucleating agents, plasticizers, impact reinforcements, stabilizers and lubricants.

The antioxidant may be at least one selected from the group consisting of a phenol type, a phosphite type, a thioether type, and an amine type antioxidant.

The releasing agent may be at least one member selected from the group consisting of a fluorine-containing polymer, a silicone oil, a metal stearate, a montanic acid metal salt, a montanic ester wax, and a polyethylene wax.

The weathering stabilizer may be at least one selected from the group consisting of a benzotriazole stabilizer, a sebacate hurst stabilizer, a triazine stabilizer, a benzophenol stabilizer, and an amine stabilizer.

The pigment may be at least one selected from carbon black having a particle size of 10 to 50 占 퐉.

[Manufacturing method]

Each component of the present invention can be applied to a compounding process for producing a molding chip by melting, kneading and extruding using an extruder to produce a polyester resin composition. In order to maximize the kneading of the composition, the mixer may be manufactured by kneading at 255 ° C to 275 ° C using a twin-screw extruder. Further, the residence time can be minimized in order to prevent thermal decomposition of the composition during melt-kneading, and it is necessary to adjust the screw rotation speed in consideration of dispersibility in the composition, and can be carried out at a rotation speed of about 200 to 300 rpm .

The polyester resin composition according to the present invention has excellent surface properties, weatherability, mechanical properties and dimensional stability. Specifically, it has a tensile strength of at least 1500 kgf / cm 2, a flexural modulus of at least 120,000 kgf / E 2.0 or less, a molding shrinkage ratio of 0.80% or less, and a good surface property are applicable to automobile wiper blades.

In describing an embodiment of the present invention, the addition amount represents parts by weight in the absence of another technique, and the production method and the molding and analysis evaluation method of the test piece were carried out according to the following methods. Hereinafter, the present invention will be described in more detail with reference to the following examples.

[ Example ]

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are for the purpose of illustrating the present invention more specifically, and the present invention is not limited thereto.

Example  1 to 5 and Comparative Example  1 to 7

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

After that, the specimens were dried and tested by injection molding machine.

Example  1 and Example  2

The content of PBT resin and PET resin was fixed, and the content of glass fiber and silane compound was changed to prepare a polyester resin composition.

Example  3 and Example  4

The content of the PBT resin and the PET resin was varied, and the content of the glass fiber and the silane compound was varied to prepare a polyester resin composition.

Example  5

The content of the PBT resin and the PET resin was changed and the content of the glass fiber and the silane compound was fixed to prepare a polyester resin composition.

Comparative Example  One

A polyester resin composition was prepared in the same manner as in Example 1, except that the silane compound was not used.

Comparative Example  2 and Comparative Example  3

A polyester resin composition was prepared in the same manner as in Example 1, except that the glass fiber content was changed.

Comparative Example  4 and Comparative Example  5

A polyester resin composition was prepared in the same manner as in Example 1 except that the PET resin content was changed.

Comparative Example  6 and Comparative Example  7

A polyester resin composition was prepared in the same manner as in Example 1, except that the PBT resin content was changed.

Impact strength, tensile strength, heat distortion temperature, mold shrinkage and surface properties were measured for the specimens of the polyester resin compositions prepared in Examples and Comparative Examples, and the results are shown in Table 2.

(1) Tensile strength

A 1/8 inch dumbbell specimen was prepared according to ASTM D638 and the tensile strength measurement rate was set at 5 mm / min.

(2) Flexural modulus

A 1/8 inch specimen was prepared in accordance with ASTM D790 and the flexural modulus measurement rate was set at 3 mm / min.

(3) Weather stability

Weather-O-Meter 2500KJ / m2, Delta-E (ΔE, color difference) after external weathering test was measured.

(4) Surface properties

Using the polyester resin composition, the specimen prepared by the screw extruder was visually observed for surface color, blackness, gas and GF appearance, and the surface properties were evaluated on the basis of the following criteria.

Good: The color of the surface is high and the gas and GF traces are not visible.

Bad: Surface color has low blackness or GS and GF visible mark.

(5) Mold Shrinkage

A circular plate test piece having a thickness of 3 mm was prepared in accordance with ASTM D955, and the test piece was allowed to stand at room temperature (23 DEG C) for 24 hours, and then measured using a vernier caliper. The direction orthogonal to the direction in which the resin enters was measured based on the gate of the injection port of the resin, and the shrinkage ratio of the present injection to the mold size was calculated and expressed in%.

division Base resin (100 parts by weight) Glass fiber
(Parts by weight) Silane compound
(Parts by weight) PBT resin
(weight%) PET resin
(weight%) Example 1 70 30 100 1.0 Example 2 70 30 110 1.2 Example 3 90 10 110 1.2 Example 4 80 20 120 1.4 Example 5 60 40 110 1.2 Comparative Example 1 70 30 110 0 Comparative Example 2 70 30 80 1.0 Comparative Example 3 70 30 130 1.6 Comparative Example 4 100 0 110 1.0 Comparative Example 5 95 5 110 1.0 Comparative Example 6 50 50 110 1.0 Comparative Example 7 0 100 110 1.0

division The tensile strength
(kgf / cm2) Flexural modulus
(kgf / cm2) Weather stability
(ΔE) Surface property Mold Shrinkage
(%) Example 1 1510 123000 1.2 Good 0.79 Example 2 1620 132000 1.4 Good 0.74 Example 3 1615 131800 1.3 Good 0.75 Example 4 1730 143000 1.5 Good 0.71 Example 5 1630 134000 1.4 Good 0.73 Comparative Example 1 1450 119000 1.4 Bad 0.74 Comparative Example 2 1220 95000 1.2 Good 0.86 Comparative Example 3 1810 153000 2.1 Bad 0.65 Comparative Example 4 1505 122500 1.9 Bad 0.82 Comparative Example 5 1510 123000 1.8 Bad 0.81 Comparative Example 6 1520 125000 2.2 Bad 0.79 Comparative Example 7 1580 129000 2.3 Bad 0.78

As can be seen from the above Table 2, the specimens prepared from the composition of the present invention had a tensile strength of at least 1500 kgf / cm 2 and a flexural modulus of 120,000 kgf / cm 2. In view of this, it can be confirmed that using the base resin mixed with PBT and PET resin as in the present invention has excellent mechanical properties, and it is preferable that 60 to 90% by weight of PBT and 10 to 40% by weight of PET are used .

In addition, when the glass fiber is used in an amount of 80 parts by weight based on the base resin (Comparative Example 2), it shows low mechanical properties and increases mold shrinkage ratio, and when used in 130 parts by weight (Comparative Example 3) Respectively.

In addition, it was confirmed that Comparative Example 1 in which the silane compound was not used had a surface property deteriorated, and that 1.0 to 2 parts by weight of the silane compound was used, so that it could satisfy both weathering stability, surface properties and mold shrinkage with high mechanical properties. This proves that the silane compound increases the reactivity between PBT and PET and glass fiber.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

Claims (8)

90 to 120 parts by weight of glass fiber and 0.1 to 2 parts by weight of a silane compound are added to 100 parts by weight of a base resin containing polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) Wherein the weight ratio of the PBT to the PET is 60:40 to 90:10.
The method according to claim 1,
Wherein the PBT resin has an intrinsic viscosity of 0.7 to 1.2 dl / g.
The method according to claim 1,
Wherein the PET resin has an intrinsic viscosity of 0.6 to 1.2 dl / g.
The method according to claim 1,
Wherein the silane compound is selected from the group consisting of 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane And at least one polyester resin composition.
The method according to claim 1,
Characterized in that the glass fibers are in the form of a umbrella with a diameter of 10 to 13 탆 and a length of 3 to 5 mm and the surface is treated with a coupling agent.
6. The polyester resin composition according to claim 5, wherein the coupling agent is a silane-based material having one kind of organic functional group selected from the group consisting of a vinyl group, an epoxy group, a mercaptan group, and an amine group.
A plastic molded article comprising the polyester resin composition according to any one of claims 1 to 6.
8. The method of claim 7,
Wherein the molded product has a tensile strength of at least 1500 kgf / cm ² and a flexural modulus of at least 120,000 kgf / cm ² .