KR100926044B1 - Polyester resins composition - Google Patents

Abstract

The present invention relates to a polyester resin composition, more specifically, the tensile strength of 580 ~ 650 kg / ㎠, impact strength properties of 3 ~ 5 kg.cm / cm, after aging at 200 ℃ for 4 hours Has a haze property of 6% or less, excellent surface smoothness and glossiness of the molded part, especially low volatility even in high temperature conditions in which the molded part is sealed for a long time, low volatility not contaminated with other parts assembled together It provides a polyester resin composition.

Polyester gaze composition, headlamp bezel, low volatility

Description

Polyester resins composition

The present invention relates to a polyester resin composition, and more particularly, to a polyester resin composition which is suitable for use in automobiles and various industrial headlamp bezels due to its excellent surface properties and low volatility in a high temperature environment.

In the case of automotive and various industrial headlamp bezels, since excellent surface characteristics are basically required characteristics, steady development of technology has been progressed to date. However, there is a need for an additional low volatility characteristic in recent years due to the improvement of quality due to the extension of the warranty period. In addition, when a large amount of volatile material is generated, the deposition amount in the post-process, or the surface defects during unpainting can be visually confirmed, and after assembly, when used as an automobile headlamp part for a long time, the internal temperature is about 150 to 180 degrees. As it rises to ℃, a problem arises in that the lens part in contact with the outside by the low molecular material or other components applied to the material adheres to the fine volatile material due to the volatile component, thereby reducing the transparency of the lens.

On the other hand, typical examples of the thermoplastic polyester include polyethylene terephthalate (hereinafter referred to as PET) and polybutylene terephthalate (hereinafter referred to as PBT). However, in the case of PET, the long-term heat resistance is excellent, but the crystallization rate of the resin is low and the crystallinity is low, so that difficulties in productivity, mold release, etc. occur in injection molding and extrusion processing. In the case of PBT, the long-term heat resistance is inferior to that of PET, but the molding productivity is improved due to the fast crystallization rate, and the market is rapidly expanding. However, since PBT has a high crystallization rate, surface addition of the reinforcing agent occurs when a large amount of reinforcing agent is added. This phenomenon is limited to use for the unpainted parts of molded parts.

As a method for improving the surface properties, there is a method of improving the heat resistance of PBT by controlling the crystallization degree and crystallization rate and increasing the surface properties by melting and mixing PBT and PET having a large number of amorphous regions at an appropriate ratio according to the product. However, when the filler (Filler) is contained, the effect of such PET is reduced, for example, in the case of glass fibers, the surface properties of the molded article is expressed, and the whitening of the molded article is greatly reduced. . Therefore, in the case of products requiring rigidity, the rigidity and surface properties are controlled as minerals. In general, even in the case of resins to which minerals are added, the surface properties are considerably inferior to products molded by the resin itself due to the surface expression of minerals.

In addition, in the case of a composition in which PBT and PET are mixed (Alloy), when the PET portion is large, the crystallization rate is slowed, so that the molding time is long and the post deformation occurs during injection molding. Accordingly, U.S. Patent Nos. 3435093, 3516975, 4344874, 4357268, 4380321, 4440889, and Japanese Patent Laid-Open No. 53-21757 describe inert inorganic metals of crystal nucleating agents and crystal growth agents. Salt, other paraffins and montanic acid were used to solve the above problems. In addition, Korean Patent Laid-Open Publication No. 2002-62403 discloses a technique of adding an alkylsilane or an alkylate silane, a silane epoxide, montan wax, a heat resistant agent, or the like to a blend of PBT and PET. Korean Patent Laid-Open Publication No. 2000-0055413 discloses a technique in which a polyphenylene sulfide resin based on a thermosetting resin is mixed with polyether imide and PBT having excellent heat resistance and impact resistance and reinforced with glass fibers. However, the above technique has shown a disadvantage in that the processability and surface condition of the polyphenylene sulfide are not applicable to the thin film molded product.

In addition, although a composition of amorphous polycarbonate resin in polyester has been proposed, the resin composition has excellent gloss and smoothness, but has high volatility at a high temperature, that is, higher than 160 ° C., and lacks heat resistance, and thus covers the lamp outer cover rather than the lamp bezel. It is applied for the purpose.

The present invention seeks to provide a polyester resin composition having a beautiful surface of a molded article, excellent glossiness, and having low volatility and excellent strength suitable for automobile headlamp bezels.

In order to achieve the above object, the present invention has a tensile strength of 580 ~ 650 kg / ㎠, impact strength properties of 3 ~ 5 kg.cm / cm, haze (aging) characteristics after aging (aging) for 4 hours at 200 ℃ It provides the polyester resin composition to have physical properties that are 6% or less.

In addition, the composition of the present invention is based on 100 parts by weight of polybutylene terephthalate, 20 to 60 parts by weight of polyethylene terephthalate, 0.2 to 0.8 parts by weight of a phosphorous compound represented by the following formula (1), silicone compound 0.2 represented by the following formula (2) To provide a polyester resin composition comprising 0.5 to 0.5 parts by weight and talc 5 to 30 parts by weight.

[Formula 1]

In the above formula, R ₁ , R ₂ and R ₃ are each an alkyl group having 1 to 5 carbon atoms,

[Formula 2]

In the above formula, R ₄ is hydrogen or an alkyl group having 1 to 10 carbon atoms, R ₅ is an alkyl group having 1 to 10 carbon atoms, R ₆ is an aryl group having 6 to 7 carbon atoms, and n is an integer of 100 to 1000.

The present invention also provides an automotive and industrial headlamp bezel made of the polyester resin composition according to the above method.

Hereinafter, the present invention will be described in detail.

Basically, the moldings for automobile bezels are large in size but thin in thickness, which causes problems of warpage after injection molding and breakage when physical properties are low. Therefore, suitable tensile strength and impact strength are also required for use in automobile headlamp bezels. Required. In other words, when the tensile strength is 580 kg / ㎠ and the impact strength is less than 3 kg.cm / cm, there is a problem of breaking during assembly, the relative strength when the tensile strength is more than 650 kg / cm 2 and the impact strength is more than 5 kg.cm / cm As a result of the lack of elongation characteristics, even a small shock is more likely to be broken. In addition, such physical properties should further include inorganic substances such as talc, so that the haze characteristics are worse, thereby lowering the low volatility and transparency.

Therefore, the present inventors, while trying to satisfy the above properties, the polybutylene terephthalate (polybutylene terephthalate, hereinafter referred to as PBT) as a main component, using a suitable content of PET, specific phosphorus compounds, silicone compounds and talc After melt-kneading in a twin screw extruder, the chip state was measured, and the heat resistance and volatilization characteristics were low. Thus, the present invention was confirmed to have low volatility and excellent strength suitable for automobile headlamp bezels. .

Accordingly, the polyester resin composition of the present invention can be used for various parts for automobile headlamp bezel or other automobiles by supplementing the volatilization property, especially when used for a long time in high temperature conditions, long-term thermal, low volatility characteristics and It is characterized by having an excellent strength.

Such compositions of the present invention comprise polyester resins, talc, phosphorus compounds and silicone compounds of specific compositions.

Polyester resin used in this invention means resin which mixed PET with PBT. When PET is mixed with the PBT, 20 to 60 parts by weight of PET is mixed with respect to 100 parts by weight of PBT, and preferably 25 to 45 parts by weight is used. In this case, the composition in which the mixed PET is not added does not exhibit excellent properties at the heat deformation temperature, which is a heat resistant property. In addition, if the content of PET is more than 60 parts by weight of PBT 100 parts by weight, the crystallization rate is too slow during injection molding, so the molding cycle is long and there is a problem such as mold release. It is not preferable because of the disadvantage.

PBT resin used in the present invention is produced by condensation polymerization through direct esterification or transesterification using 1,4-butanediol and terephthalic acid or dimethyl terephthalate as monomers, and its intrinsic viscosity is 0.8-1.4 dl / It is preferable to use about g resin. PBT usable in the present invention may use Kolon's brand name SPESIN KP210, but the present invention is not limited thereto.

In addition, polyethylene terephthalate (PET) resin is produced by condensation polymerization through direct esterification or transesterification using ethanol and terephthalic acid or dimethyl terephthalate as monomers, and its intrinsic viscosity is about 0.4 to 0.8 dl / g. It is preferable to use resin.

In the present invention, talc is used for thermal properties, mechanical strength and dimensional stability. It is preferable that the particle size of the talc used by this invention is 3-10 micrometers. If the particle size is smaller than 3 μm, it is difficult to add to the extruder in the resin manufacturing process, and there is a problem of quantification and productivity. This causes a problem that is not excellent. As a preferable example of the particle | grains of the talc used by this invention, the talc whose average is 5-6.5 micrometers can be used.

The talc is added in an amount of 20 to 50 parts by weight based on 100 parts by weight of the PBT resin. If the content is less than 20 parts by weight, the thermal properties, mechanical strength and dimensional stability are poor. There is a problem in that the surface characteristics of the mineral surface is lowered.

In addition, in the case of using a highly volatile heat resistant agent that is not excellent in thermal stability, it is severely decomposed in the course of the twin screw extruder, and thus does not act as a heat resistant agent or a vacuum system that removes low molecular material from the discharge portion of the tip of the extruder. It is not preferable because a large amount of the heat-resistant agent added by the present is not present in the resin or when it is used as a volatile component when applied to a high temperature environment in a product state.

Therefore, in the present invention, it is used for automobile bezels and to reinforce the heat resistance of the volatiles included in the composition, there is a feature of using a phosphorus-based compound of formula (1).

[Formula 1]

In the above formula, R ₁ , R ₂ and R ₃ are each an alkyl group having 1 to 5 carbon atoms.

The compound of the formula (1) used in the present invention has excellent long-term heat resistance having heat resistance and exhibits excellent low volatility and beautiful surface properties.

Examples of phosphorus compounds excellent in improving heat resistance used in the present invention include bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phthalate (Bis (2,6-di). -tert-butyl-4-methyl phenyl) pentaerythritol-di-phosphate) may be used, but the present invention is not limited thereto.

It is preferable that the addition amount of the said phosphorus compound is 0.2-0.8 weight part with respect to 100 weight part of PBT resin. More preferably, 0.3 to 0.5 weight part is preferable. If the content is less than 0.2 parts by weight, long-term heat resistance cannot be obtained. If the content is more than 0.8 parts by weight, the results and surface properties may be impaired in terms of heat resistance effect when used less than that.

In addition, the present invention is characterized by using a silicone-based compound of the formula (2) to further reinforce the heat resistance and to solve the above problems.

[Formula 2]

In the above formula, R ₄ is hydrogen or an alkyl group having 1 to 10 carbon atoms, R ₅ is an alkyl group having 1 to 10 carbon atoms, R ₆ is an aryl group having 6 to 7 carbon atoms, and n is an integer of 100 to 1000.

The silicon compound of Formula 2 used in the present invention is an organic compound in which an organic material is present at each end portion. This compound has good reactivity with polyester, melts and kneads well, and has a secondary role in improving heat resistance. As an example of the compound of Formula 2, Dow Corning's silicon-based compound may be used.

It is preferable that the usage-amount of the said silicone type compound is 0.2-0.5 weight part with respect to 100 weight part of PBT resin. If the content is less than 0.2 parts by weight, it is not possible to obtain a heat-resistant effect, and when the content is more than 0.5 parts by weight, there is a problem of lowering the physical properties to an excessive content in the resin.

In addition, the resin composition according to the present invention is prepared by melt kneading by using a twin screw extruder equipped with a pressure reducing device with two conventional inlets, which is retained to maximize the mechanical properties of the resin composition and to prevent thermal decomposition of the composition during melt kneading. It is good to minimize the time.

Moreover, the composition of this invention can mix | blend additives, such as a heat stabilizer, an antistatic agent, a plasticizer, suitably as needed within the range which does not impair the objective.

The composition of the present invention as described above has a tensile strength of 580 ~ 650 kg / ㎠, impact strength properties of 3 ~ 5 kg.cm / cm, in particular the haze characteristic is 6% or less (after 200 ℃ x 4hr aging) It exhibits low volatility.

The present invention has an effect of providing a polyester resin composition suitable for automobile headlamp bezel because the surface of the molded article is beautiful, excellent gloss, especially low volatility and excellent strength.

Hereinafter, preferred examples and comparative examples are presented to aid in understanding the present invention. However, the following examples are only for illustrating the present invention, and the present invention is not limited thereto.

When describing an embodiment of the present invention, the addition amount represents parts by weight unless otherwise stated, and the production method and the method of forming and analyzing the test piece were performed according to the following method.

Example 1

30 parts by weight of PET (polyethylene terephthalate) to 100 parts by weight of PBT (polybutylene terephthalate) resin as a primary raw material inlet using a twin screw extruder heated to 220 to 260 ° C, and a phosphorous compound of formula 1 used as a heat resistant agent 0.2 parts by weight of (Bis (2,6-di-tert-bytyl-4-methyl phenyl) pentaerythritol-di-phosphate) and 0.3 parts by weight of the silicone compound of Formula 2 were added. In addition, 48 parts by weight of talc (Talc, particle size: 6㎛) with respect to 100 parts by weight of PBT resin was introduced into a secondary inlet located in the middle of the cylinder, it was prepared into pellets through a hot melt kneading process. The pellet chips were dried with a dehumidifying dryer at a temperature of 130 ° C. for 5 hours. The dried pellet-like material was produced as a test piece for surface property evaluation. In addition, volatilization characteristics were evaluated in a dried chip state.

And after drying using a dehumidifying dryer for 5 hours at 110 ℃ using a screw injection machine heated to 220 ~ 240 ℃ to prepare a test specimen for ASTM standard evaluation, the physical properties were evaluated, and the results are shown in Table 2.

<Examples 2 to 3 and Comparative Examples 1 to 8>

100 parts by weight of PBT resin, PET resin, phosphorus-based compound (Bis (2,6-di-tert-bytyl-4-methylphenyl) pentaerythritol-di-phosphate), silicon-based compound, talc content is changed as shown in Table 2 below Other conditions and compositions were carried out in the same manner as in Example 1.

In addition, the Examples and Comparative Examples were carried out in the same manner as usual in the above-mentioned conditions, and then the physical properties were measured by the following evaluation method. The results are shown in Table 2.

TABLE 2

division Composition (part by weight) A B C D Example 1 30 0.2 0.3 48 Example 2 25 0.2 0.3 45 Example 3 40 0.3 0.2 45 Comparative Example 1 15 0.2 0.3 45 Comparative Example 2 65 0.2 0.3 45 Comparative Example 3 30 0.2 0.3 15 Comparative Example 4 30 0.2 0.3 60 Comparative Example 5 30 - 0.3 45 Comparative Example 6 30 1.0 0.3 45 Comparative Example 7 30 0.2 - 45 Comparative Example 8 30 0.2 0. 8 45

Note) In Table 1 above,

A: PET, polyethylene terephthalate having an intrinsic viscosity (IV) of 0.63 dl / g

B: phosphorus compound (Bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphate)

C: silicon compound (Formula 2)

D: talc, particle size 6㎛, Kochi

[Assessment Methods]

(1) surface properties

Each resin composition made after melting and kneading was dried in a chip state using a dehumidifying dryer, and then a 150-meter injection molding machine manufactured by Nisei Co., Ltd., using a disc mold 10 cm in diameter and 3.2 mm thick. And the mold temperature was fixed at 80 degreeC. Thereafter, the degree of gas and flow marks on the surface of the molded product released under the conditions of injection pressure 800 kg / cm 2 and holding pressure 400 kg / cm 2 was visually observed.

(2) Haze and light transmittance:

The haze% and light transmittance were evaluated to evaluate the volatilization characteristics. Each resin composition made after melting and kneading was dried in a chip state and weighed by 5 g and covered with a transparent glass, respectively, put in a saale. After heating 4 hours on the hotplate fixed at 200 degreeC, the shale lid was evaluated for the light transmittance and the haze degree using the haze analyzer.

Haze% evaluation was performed on 23 +/- 2 degreeC and 50 +/- 5% of relative humidity based on ASTMD1003-61. The results are expressed in% haze and light transmittance and can be obtained by

[Calculation 1]

Haze Percent = T _d / T _t × 100

Where

T _d = (T ₄ -T ₃ (T ₂ / T ₁ )] / T ₁ ,

T _t = T ₂ / T ₁

T _t : total light transmittance

T _d : total light scattering degree

T ₁ : incident light amount

T ₂ : Total transmitted light amount by the test piece

T ₃ : Amount of scattered light by measuring instrument

T ₄ : Amount of scattered light by test piece and measuring instrument

In the case of light transmittance, more than 90% was judged to be good, and haze% was determined to be less than 6 haze% by evaluation method related to volatile characteristics.

The smaller the haze% and the higher the light transmittance, the less volatile content is under the high temperature evaluation condition.

(3) measuring tensile and impact properties

Tensile strength: measured according to ASTM-D-638

Izod Impact Strength: measured according to ASTM-D-256

TABLE 2

division Haze% Light transmittance (%) Surface Characteristics (Flow Marks) Tensile Strength (Kg / ㎠) Impact Strength (Kg cm / cm) Example 1 4.0 92.2 ◎ 620 3.5 Example 2 5.5 91.6 ◎ 600 3.2 Example 3 3.2 95.1 ◎ 625 3.6 Comparative Example 1 8.0 84.0 × 575 3.1 Comparative Example 2 5.0 92.0 × (unmodified) 555 3.2 Comparative Example 3 4.5 95.5 ◎ 565 2.7 Comparative Example 4 23.1 78.2 × 650 7.2 Comparative Example 5 17.1 81.1 × 615 3.4 Comparative Example 6 5.5 90.5 ◎ 600 3.1 Comparative Example 7 15.1 84.1 × 615 3.4 Comparative Example 8 5.8 90.5 ◎ 595 3.1   Note) ※ Surface characteristics: ◎ Excellent, X Poor

In Table 2, as a result of evaluating light transmittance, haze% and surface properties of the test piece produced by the resin composition according to the Examples and Comparative Examples, the polyester resin composition according to the present invention has a high temperature volatilization characteristics of the product after molding It is excellent in improving the phenomenon that the lens surface becomes opaque due to the low volatility when used for the bezel of automobile headlamp parts. On the other hand, in Comparative Examples 1 to 8, the surface of the lens was opaque due to volatile components, resulting in poor haze characteristics, light transmittance and surface characteristics.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

Since the resin composition of the present invention has excellent volatilization and surface properties, it can be used for automotive headlamp bezel applications and industrial unpainted parts used in high temperature environmental conditions.

Claims (4)

20 to 60 parts by weight of polyethylene terephthalate, 0.2 to 0.8 parts by weight of a phosphorus compound represented by Formula 1, 0.2 to 0.5 parts by weight of a silicon compound represented by Formula 2, and talc based on 100 parts by weight of polybutylene terephthalate To 50 parts by weight, Polyester having tensile properties of 580 to 650 kg / ㎠, impact strength of 3 to 5 kg.cm/cm, and haze property of 6% or less after aging at 200 ° C. for 4 hours. Resin composition. [Formula 1]

In the above formula, R ₁ , R ₂ and R ₃ are each an alkyl group having 1 to 5 carbon atoms, [Formula 2]

In the above formula, R ₄ is hydrogen or an alkyl group having 1 to 10 carbon atoms, R ₅ is an alkyl group having 1 to 10 carbon atoms, R ₆ is an aryl group having 6 to 7 carbon atoms, and n is an integer of 100 to 1000. delete The polyester resin composition of claim 1, wherein the talc has a particle size of 3 μm to 10 μm. An automotive and industrial headlamp bezel made of the polyester resin composition according to claim 1.