KR20060071685A - Thermoplastic polyester resin compositions - Google Patents

Abstract

The present invention relates to a thermoplastic polyester resin composition, and more specifically, to a resin composition comprising polybutylene terephthalate and polyethylene terephthalate, talc, a branched fatty acid ester which is a compound represented by the following Chemical Formula 1 as an internal lubricant, and It relates to a thermoplastic polyester resin composition comprising a reactive organofunctional silane represented by the formula (2). The resin composition is excellent in mechanical properties and metal material deposition properties, especially in a high temperature environment because less generation of migration (migration) material in the resin is excellent in the head lamp optical properties, the material for automotive head lamp bezel (head lamp bezel) It can be usefully used.

[Formula 1]

(In Formula 1, n is an integer of 14 to 18.)

[Formula 2]

(In Formula 2, n is an integer of 1 to 20.)

Polybutylene Terephthalate, Polyethylene Terephthalate, Thermoplastic, Polyester, Resin, Composition, Migration, Headlamp Bezel

Description

Thermoplastic polyester resin compositions

The present invention relates to thermoplastic polyester resin compositions that can be used as materials for automotive headlamp bezels.

Generally, plastic materials widely used as resins for automobile head lamp bezels include polycarbonate resins or acrylonitrile butadiene starene triple copolymer resins or polybutylene terephthalate (hereinafter referred to as PBT) and polyethylene terephthalate (hereinafter referred to as PET). It is a blend. Depending on the design structure and the type of bulbs or other factors, the car head lamps have different rising temperatures at lighting time, and it is natural to use resins having higher heat resistance as they rise to higher temperatures. Therefore, relatively high heat resistance PBT and PET blends are the most used resin.

However, as already known, PET and PBT resins have a problem that the cycle time is long and post deformation occurs during injection molding due to the slow crystallization rate. To remedy this problem, U.S. Pat.Nos. 3,435,093, 3,516975, 4,344,874, 4,357,268, 4,380,621 and 4,440889, and British Patent No. 1,249,252, Japanese Patent Publication 54-38622 Japanese Patent Laid-Open No. 53-21757 et al. Attempted to improve the moldability of polyester resins using crystal nucleation agents, inert inorganic metal salts of crystal growth agents, and other paraffins and montan acids. In Korean Patent Laid-Open Publication No. 2002-62403, alkyl silane or alkylate silane, silane epoxide, montan wax, and heat-resistant agent were added to PBT and PET blend to improve surface properties and secondary processability.

However, all of these techniques use low molecular weight additives, which results in a material that migrates in the resin due to the elevated temperature when the head lamp is turned on, and the migrated material solidifies on the inner surface of the head lamp lens to finally There is a technical problem of lowering light transmittance.

Accordingly, in order to solve the above problems, the inventors of the present invention have excellent mechanical properties and metal deposition properties in secondary processing while PBT and PET blends retain moldability in the injection process, and are particularly elevated when the head lamp is turned on. In order to provide a polyester resin composition in which fewer substances are migrated in the resin even at a temperature, the present invention has been accomplished by using a resin composition, molecular weight change, and various additives.

Accordingly, an object of the present invention is excellent in mechanical properties, metal material deposition properties, in particular, because the less migration material in the resin is generated under high temperature environment and excellent in the head lamp optical properties, it can be used as a material for automobile head lamp bezel It is to provide a thermoplastic polyester resin composition.

In order to achieve the above object, the thermoplastic polyester resin composition of the present invention is talc 0.01 to 45 to 100 parts by weight of a resin composition comprising 60 to 99.9% by weight of polybutylene terephthalate and 0.1 to 40% by weight of polyethylene terephthalate. It is characterized by comprising 0.01 to 0.4 parts by weight of the branched fatty acid ester which is a compound represented by the following formula (1) as parts by weight, internal lubricant and 0.01 to 0.4 parts by weight of the reactive organic functional silane represented by the following formula (2).

(In Formula 1, n is an integer of 14 to 18.)

(In Formula 2, n is an integer of 1 to 20.)

When the polyester resin composition is used as a material for automobile head lamp bezels, the mechanical properties and metal material deposition properties are excellent, and in particular, when the lamp is turned on, less material is migrated in the resin under a high temperature environment. There is an effect that does not lower.

Polybutylene terephthalate (hereinafter, PBT) used in the polyester resin composition of the present invention is generally a linear PBT resin prepared by condensation polymerization of butanediol on dimethyl terephthalate or terephthalic acid, preferably phenol and tetra The intrinsic viscosity of the PBT resin measured at 30 ° C by dissolving 0.5% (wt / volume) of PBT resin in a weight percent in a solvent with a chromoethane of 50:50 is used. Preferably, the intrinsic viscosity measured as described above is used 0.7 ~ 0.9 dl / g. It is difficult to secure mechanical properties when the intrinsic viscosity of the PBT resin is less than 0.5 dl / g, and when it exceeds 1.1 dl / g, thermal decomposition products of the resin are generated by the shear force as much as the viscosity increase of the resin during the extrusion process. This is because there are relatively many problems.

In addition, the content of the PBT resin is used in 60 to 99.9% by weight to 100 parts by weight of the total resin composition, which is a problem of poor surface quality when using less than 60% by weight of PBT resin, exceeding 99.9% by weight If used, the solidification rate of the resin is increased, there is a problem that the productivity is lowered and the post-deformation relatively occurs.

Polyethylene terephthalate (hereinafter referred to as PET) resin used in the polyester resin composition of the present invention is generally a linear PET resin prepared by condensation polymerization of terephthalic acid and ethylene glycol, preferably phenol and tetrachloroethane. 50: A viscosity of 0.5% (wt / volume) of the PET resin was dissolved in a solvent by weight in a viscosity of 50, and the intrinsic viscosity of the PET resin measured at 30 ℃ is used 0.5 ~ 1.0 dl / g. This shows a problem in mechanical properties when the intrinsic viscosity is less than 0.5 dl / g, and when it exceeds 1.0 dl / g, the pyrolysis product of the resin is generated by the shear force as much as the viscosity increase of the resin in the extrusion process, similar to the PBT resin. This is because there is a problem that a relatively large amount of material occurs.

In addition, the content of the PET resin is used in 0.1 to 40% by weight to 100 parts by weight of the total resin composition, which is a problem that the surface quality is lowered when using less than 0.1% by weight of PET resin, in excess of 40% by weight If used, the solidification rate of the resin is increased, there is a problem that the productivity is lowered and the post-deformation relatively occurs.

In the polyester resin composition of the present invention, talc is added to variously control the heat resistance of the resin composition, and the amount of the talc used is 0.01 to 45 parts by weight based on 100 parts by weight of the total resin. When the content is less than 0.01 parts by weight, the crystallization rate of the resin composition does not improve, which adversely affects the molding productivity and post deformation, and when used in excess of 45 parts by weight, a synergistic effect of heat resistance is obtained. This is because there is a problem that the surface gloss is poor.

On the other hand, since the shear force that the resin receives in the extrusion process together with the molecular weight of the resin affects the amount of migration material generated in the high temperature environment, the additive that can reduce the shear force that the resin receives in the extrusion process (lubricant) This additive should basically not migrate even at relatively high temperatures.

Therefore, in the polyester resin composition of the present invention, a branched fatty acid ester having 14 to 18 carbon atoms, which is a compound represented by Formula 1, is used as an internal lubricant, which reduces kneading by reducing shear force in an extrusion process of the resin. Add to facilitate.

In addition, the amount of the fatty acid ester compound used is 0.01 to 0.4 parts by weight, preferably 0.1 to 0.2 parts by weight based on 100 parts by weight of the total resin. If the content of the branched fatty acid ester compound is less than 0.01 parts by weight, it is difficult to expect a role as a lubricant, and it is not effective in preventing the generation of migration substances, and when the content exceeds 0.4 parts by weight, it is itself migrated to resin. Because it will adversely affect.

In addition, the thermoplastic polyester resin composition needs a binder that improves the bonding strength between the polyester resin and the talc, which is an inorganic filler, and also exhibits less migration under a high temperature environment.                     

Therefore, the said resin composition of this invention uses reactive organic functional silane represented by the said Formula (2) as a binder. In addition, the reactive organic functional silane is used in an amount of 0.01 to 0.4 parts by weight based on 100 parts by weight of the total resin. This is because when the content of the reactive organofunctional silane is less than 0.01 part by weight, the role as a binder is insufficient, and when the content exceeds 0.4 part by weight, there is a problem that the migration material increases.

On the other hand, the resin composition of the present invention may further include additives, such as antioxidants, flame retardants, mold release agents, antistatic agents, etc., according to the other needs, the amount of these are usually used.

The resin composition and the additive of the present invention are mixed with a mechanical mixer and then introduced through a primary inlet to a twin screw extruder to prepare a resin composition in a temperature range of 230 to 260 ° C. of the twin screw extruder. At this time, when the temperature is out of the above-mentioned range, in particular, when the temperature exceeds 260 ℃, the possibility of thermal decomposition of PBT and PET resin increases, which may adversely affect the mechanical properties and the surface quality of the final product. Low melt viscosity may cause a lot of migration material in the resin composition due to the generation of frictional heat by the shear force.

Hereinafter, the present invention will be described in more detail based on the following Examples and Experimental Examples, but the present invention is not limited only to these examples.

<Examples 1-5 and Comparative Examples 1-4>                     

In order to prepare the thermoplastic polyester resin composition, after mixing the composition with the composition and content as shown in Table 1 by a mechanical mixer, the obtained mixture was introduced into the primary inlet of the twin screw extruder, extrusion temperature 230 ~ 260 ℃, screw The rotational speed was extruded at 150 ~ 250 rpm to prepare a thermoplastic polyester resin composition. At this time, the twin screw extruder used during extrusion was made in Germany (Wenerner & Pfleiderer), and the diameter of the extruder was 25 mm and the ratio of length and diameter was 40. Meanwhile, TRIBIT 1300 (intrinsic viscosity 0.70dl / g, Samyang Corp.), TRIBIT 1800 (intrinsic viscosity 0.70dl / g, Samyang Corp.) as PBT, SB chip (intrinsic viscosity 0.64dl / g, Huvis) as PET, Rossi as fatty acid ester Loxiol EP 861 (a branched fatty acid ester with n = 16), Licowax OP (Clariant) with Montan Ox, 155F wax (Nippon Seiro) with olefin wax, Coupling Agent) A-187 (Union Carbide, n = 1 in the formula 2), 204 (Dow Coring, organic silane compound without a reactive group), Songnox 1010, Talc used NA-400 (Youngwoo Chemical). The results are shown in Table 1 below.                     

ingredient Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 PBT (TRIBIT1300) 73 73 73 85 73 0 73 55 73 PBT (TRIBIT1800) - - - - - 73 - - - PET 27 27 27 15 27 27 27 45 27 Fatty acid ester 0.2 0.2 0.2 0.4 0.2 0.2 - 0.2 0.5 Montan wax - - - - - - 0.2 - - Olefin Wax - - - - - - 0.2 - - Binder A-187 0.1 0.2 0.2 0.3 0.2 0.1 - 0.1 0.2 Binder 204 - - - - - - 0.2 - - Antioxidant 0.1 0.1 0.2 0.2 0.1 0.1 0.1 0.1 0.2 Talc 35 35 35 35 0.1 34 35 35 35

Experimental Example 1. Experiment of Degree of Migration Material in Resin Under High Temperature Environment>

In order to evaluate the degree of migration material in the resin under the high temperature environment of the thermoplastic polyester resin compositions prepared in Examples 1 to 5 and Comparative Examples 1 to 4, an injection molding machine BA 750 CD Plus (Battenfeld) was used. After making a specimen on a sheet 50 cm wide, 60 cm long, and 3 mm thick, cut it into 2 mm wide and 2 mm long, and then 5 g each in a 50 mm diameter glass Shaale container with a glass lid. The amount of migrating material condensed on the Shale glass cover after 5 hours of holding the temperature at 165 ° C. on the hot plate was evaluated using a haze meter. The injection molding conditions were injection temperature 240-250-250-260 (℃), injection pressure 750 kgf / cm ² , injection speed 60 mm / s, weighing speed 100 rpm, and the results are shown in Table 2 below. .

As shown in Table 2, it was confirmed that the composition of Examples 1 to 5 had a very low haze value than the compositions of Comparative Examples 1 to 4.

Therefore, it was found that the thermoplastic polyester resin composition of the present invention generated less migration material in the composition even under a high temperature environment.

Experimental Example 2. Mechanical Properties and Metal Material Deposition Properties Experiments

In order to measure the mechanical properties and metal material deposition properties of the specimen prepared in Experimental Example 2, the actual automotive headlamp bezel was molded to evaluate mechanical properties, particularly tensile strength, flexural strength and surface properties after molding, in particular aluminum deposition properties. It was. At this time, the mechanical property measurement criteria were measured in accordance with ASTM standards, using aluminum as a metal material, the aluminum deposition property is formed by the actual bezel using the respective compositions of Example 1 and then as a hard coating agent on the surface of the molded article first After coating and performing aluminum deposition in a vacuum state, the deposition surface was cut at regular intervals with a sharp blade to determine the degree of surface peeling, and the results are shown in Table 2 below.

As shown in Table 2, the compositions of Examples 1 to 5 were slightly superior or almost similar in tensile strength and flexural strength as compared with the compositions of Comparative Examples 1 to 4, and confirmed that aluminum deposition properties were very excellent.

Therefore, it was found that the thermoplastic polyester resin composition of the present invention is more excellent in depositing metallic materials while retaining mechanical properties possessed in the prior art.

ingredient Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Tensile Strength (kg / cm ² ) 650 650 630 630 600 640 630 640 630 Flexural Strength (kg / cm ² ) 880 890 880 890 800 900 880 880 890 Aluminum deposition ◎ ◎ ◎ ◎ ◎ ㅇ ㅇ △ △ Haze 2.5 2 2 2 1.5 12 25 22 26

◎: best, ㅇ: excellent, △: good

As described above, the thermoplastic polyester resin composition of the present invention has excellent mechanical properties and metal material deposition properties, and especially in high temperature environments, since less migration material is generated in the resin, the headlamp optical characteristics are excellent. It can be usefully used as a material for (Bezel).

Claims (5)

Branched fatty acid ester, which is a compound represented by the following formula 1 as talc 0.01 to 45 parts by weight, internal lubricant, 100 parts by weight of a resin composition comprising 60 to 99.9% by weight of polybutylene terephthalate and 0.1 to 40% by weight of polyethylene terephthalate A thermoplastic polyester resin composition comprising 0.01 to 0.4 parts by weight and 0.01 to 0.4 parts by weight of a reactive organic functional silane represented by the following formula (2). [Formula 1]

 (In Formula 1, n is an integer of 14 to 18.) [Formula 2]

(In Formula 2, n is an integer of 1 to 20.) The thermoplastic polyester resin composition of claim 1, wherein the polybutylene terephthalate resin is a linear polybutylene terephthalate resin prepared by polycondensation of butanediol on dimethyl terephthalate or terephthalic acid. The thermoplastic polyester resin composition according to claim 2, wherein the intrinsic viscosity of the polybutylene terephthalate resin is 0.5 to 1.1 dl / g. The thermoplastic polyester resin composition of claim 1, wherein the polyethylene terephthalate resin is a linear polyethylene terephthalate resin prepared by condensation polymerization of terephthalic acid and ethylene glycol. The thermoplastic polyester resin composition of claim 4, wherein the polyethylene terephthalate resin has an intrinsic viscosity of 0.5 to 1.0 dl / g.