KR102200890B1 - Polycarbonate resin composition having excellent chemical resistance in appearance characteristics - Google Patents

Abstract

When a metal pigment is applied to a conventional polycarbonate and polycyclohelylenedimethylene terephthalate alloy, a chemical-resistant polycarbonate resin composition with excellent appearance characteristics can solve the problem that it is difficult to achieve a uniform metal surface due to poor compatibility with the resin. Is initiated. The present invention (A) 60 to 89% by weight of a polycarbonate resin; (B) 10 to 39% by weight of polycyclohexylenedimethylene terephthalate resin; (C) 0.01-3% by weight of internal lubricant; And (D) 0.01-5% by weight of a metal pigment; it provides a polycarbonate resin composition comprising.

Description

Polycarbonate resin composition having excellent chemical resistance in appearance characteristics}

The present invention relates to a polycarbonate resin composition, and more particularly, to a resin composition that can express a uniform metallic color on the surface, and has excellent mechanical properties and chemical resistance, so that it can be applied as interior and exterior materials for electric/electronic parts including automobiles. About.

Polycarbonate has excellent mechanical properties such as heat resistance and impact resistance, and is used in various fields such as interior and exterior materials of automobiles and electric and electronic devices, but has problems of product deterioration such as degradation of physical properties and discoloration due to household chemicals (disinfectants, fragrances, etc.) On the other hand, polyester-based resins have excellent chemical resistance to chemicals and are widely used in household containers such as various detergents and cosmetics, but their heat resistance is low and their use in high temperature environments is limited.

As such, various attempts have been made to supplement and overcome the problems of the two resins, and among them, a method of alloying polycarbonate and polyester resins has been actively developed.

Polycarbonate (PC) and polycyclohelylenedimethylene terephthalate (PCT) alloy not only overcome the shortcomings of the two resins by improving chemical resistance and heat resistance for chemicals, but also realize color based on transparency, especially metallic color. There is an advantageous advantage in exerting. However, when the metal pigment is applied, not only the compatibility with the resin is poor, but also it is difficult to realize a uniform metal surface due to the tendency to clump together.

Korean Patent Publication No. 2018-0031474 discloses a polycarbonate resin composition that exhibits excellent metallic color based on chemical resistance and transparency, but does not mention realization of a uniform metallic color on the surface.

In addition, Korean Patent No. 0856747 discloses a polyester/polycarbonate blend that can overcome the problem of lowering the transparency of a polyester/polycarbonate blend and at the same time secure excellent heat resistance, but it is applied to various housings based on transparency. It does not mention the color toning, imparting metallic color and chemical resistance.

In addition, Korean Laid-Open Patent No. 2009-0080132 discloses a method of manufacturing a thermoplastic resin that can be used at high temperatures while maintaining transparency through a blend of polycarbonate and polyester, and its use, but does not mention the color (metal) implementation. have.

The present invention was devised to solve the above problem, and when a metal pigment is applied to a conventional polycarbonate and polycyclohelylenedimethylene terephthalate alloy, it is difficult to achieve a uniform metal surface due to poor compatibility with the resin. It is intended to provide a chemical-resistant polycarbonate resin composition having excellent appearance properties.

The present invention in order to solve the above problems, (A) 60 to 89% by weight of a polycarbonate resin; (B) 10 to 39% by weight of polycyclohexylenedimethylene terephthalate resin; (C) 0.01-3% by weight of internal lubricant; And (D) 0.01-5% by weight of a metal pigment; it provides a polycarbonate resin composition comprising.

In addition, the internal lubricant is polyethylene wax or polypropylene wax, and provides a polycarbonate resin composition, characterized in that the weight average molecular weight is 5,000 to 10,000 g/mol.

In addition, the polycarbonate resin composition is a polycarbonate resin composition, characterized in that the light transmittance (ASTM D1003, 3 mm thick injection specimen, based on the addition of pigment) is 65% or more, and the gloss uniformity according to the following measurement method is less than 5 Provides.

[Method of measuring gloss uniformity]

A specimen (150×150×2.5 mm) injected with the resin composition at an injection temperature of 260° C. was adjusted for 24 hours under conditions of 23±2° C. and 50±5% relative humidity, and then 5 points (each corner and center Part), using a gloss meter (angle 60°) to measure the gloss and calculate the dispersion value.

The polycarbonate resin composition according to the present invention contains an internal lubricant of a specific composition when applying a metal pigment to an alloy of polycarbonate resin and polycyclohexylenedimethylene terephthalate, thereby maintaining excellent chemical resistance and dispersibility of the metal pigment. It is possible to provide a chemical-resistant polycarbonate resin composition capable of realizing high-quality appearance characteristics by providing uniformity to the metallic color of the surface.

1 is a view showing a measurement portion of a specimen when evaluating gloss uniformity in a test example of the present invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail. In describing the present invention, when it is determined that a detailed description of a related known technology may obscure the subject matter of the present invention, a detailed description thereof will be omitted. Throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components, unless otherwise stated.

The present inventors have conducted research to develop a polycarbonate resin that can solve the problem that it is difficult to realize a uniform metal surface due to poor compatibility with the resin when a metal pigment is applied to a conventional polycarbonate and polycyclohelylenedimethylene terephthalate alloy. As a result, when a metal pigment is applied to an alloy of polycarbonate resin and polycyclohexylenedimethylene terephthalate, it contains an internal lubricant of a specific composition, thereby maintaining excellent chemical resistance and improving the dispersibility of the metal pigment. It was discovered that it is possible to realize high-quality appearance characteristics by imparting uniformity to the color, and came to the present invention.

Therefore, the present invention (A) 60 to 89% by weight of a polycarbonate resin; (B) 10 to 39% by weight of polycyclohexylenedimethylene terephthalate resin; (C) 0.01-3% by weight of internal lubricant; And (D) 0.01 to 5% by weight of a metal pigment; discloses a polycarbonate resin composition comprising.

The resin composition has a light transmittance (ASTM D1003, 3 mm thick injection specimen, based on no pigment added) of 65% or more, preferably 70% or more, and exhibits a characteristic of less than 5 gloss uniformity according to the following measurement method. It is possible to achieve high-quality appearance characteristics by giving uniformity to the product, and as a result of the chemical resistance test according to the method described later, it is maintained at a level of 75% or more, preferably at least 80% of the tensile strength before the test, and It exhibits chemical resistance that maintains a level of 50% or more, preferably 55% or more of the elongation.

[Method of measuring gloss uniformity]

A specimen (150×150×2.5 mm) injected with the resin composition at an injection temperature of 260° C. was adjusted for 24 hours under conditions of 23±2° C. and 50±5% relative humidity, and then 5 points (each corner and center Part), using a gloss meter (angle 60°) to measure the gloss and calculate the dispersion value.

Hereinafter, each component of the polycarbonate resin composition according to the present invention will be described in more detail.

(A) Polycarbonate resin

The polycarbonate (PC) resin used in the present invention has excellent impact resistance, heat resistance, weather resistance, self-extinguishing property, flexibility, processability and transparency, and excellent weather resistance, maintaining high physical properties for a long period of time, and excellent heat resistance and cold resistance. Maintains performance despite changes.

The resin of the polycarbonate is not particularly limited, but may be a polymerized resin including a bisphenol-based monomer and a carbonate precursor.

The bisphenol-based monomer is, for example, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ketone, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A; BPA), 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cyclohexane (bisphenol Z; BPZ), 2,2-bis(4-hydroxy-3) ,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2 ,2-bis(4-hydroxy-3chlorophenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl )Propane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane and α,ω-bis[3-(ο-hydroxyphenyl)propyl] It may be one or more selected from the group consisting of polydimethylsiloxane.

In addition, the carbonate precursor is, for example, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate , Bis (diphenyl) carbonate, carbonyl chloride (phosgene), triphosgene, diphosgene, carbonyl bromide and bishaloformate may be one or more selected from the group consisting of.

In the present invention, the polycarbonate resin may be, for example, a polymer of bisphenol A having a weight average molecular weight (Mw) of 10,000 to 200,000, preferably 20,000 to 50,000.

In addition, the polycarbonate resin may have a melt index (300°C, 1.2 kg load) of 5 to 15 g/10min, more preferably 7 to 13 g/10min. It has excellent processability and moldability within the above melt index range, and has an excellent balance of properties. If the melt index is lower than the above range, the flowability may be insufficient and unmolding may occur, and if the melt index is high, the impact strength tends to be slightly lowered.

In the present invention, the polycarbonate resin is included in an amount of 60 to 89% by weight in the total resin composition for flowability, impact resistance, and processability of the final thermoplastic resin composition, preferably 65 to 84% by weight, more preferably 75 to It may be included in an amount of 84% by weight.

(B) Polycyclohexylenedimethylene terephthalate resin

The polycyclohexylenedimethylene terephthalate (PCT) resin used in the present invention includes terephthalic acid (TPA) or dimethylterephthalate (DMT) and 1,4-cyclohexanedimethanol, CHDM) or crystalline polyester produced by transesterification and polycondensation reaction, and has a very high melting point and a very fast crystallization rate.

The PCT resin has excellent heat resistance, chemical resistance, moisture absorption and flow resistance compared to polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), which are general-purpose polyesters, and among them, the heat deflection temperature is 245~260℃ , It is an engineering plastic that can replace metal with a continuous use temperature of 130~150℃. Compared with other polymer resins, such PCT resins have very good color stability and have a significantly lower moisture absorption rate, so they can be used in various ways for housings of electrical and electronic products.

In the present invention, the PCT resin may be included in an amount of 10 to 39% by weight, preferably 15 to 34% by weight, more preferably 15 to 24% by weight in the total resin composition. When the content of the PCT resin is less than 10% by weight, the degree of improvement in chemical resistance may be insufficient, and when it exceeds 39% by weight, it may be difficult to implement a metallic color due to decreased transparency.

(C) internal lubricant

In the present invention, the internal lubricant is an oily solid having slipperiness and plasticity, and is included as a part of the thermoplastic resin composition to improve the fluidity and releasability of the composition, and in particular, improve compatibility and dispersibility of metal pigments during alloying. It plays a role to let.

In this way, the use of various internal lubricants may be considered to improve the dispersibility of the metal pigments of the polycarbonate resin and the polycyclohexylenedimethylene terephthalate alloy resin, but in the present invention, in particular, polyethylene wax or polypropylene wax is used. When it was confirmed that the ideal metal pigment dispersibility can be exhibited.

In this case, the internal lubricant may be included in an amount of 0.01 to 3% by weight, preferably 0.05 to 2% by weight, more preferably 0.15 to 0.9% by weight in the total resin composition. If the content of the internal lubricant does not reach a certain level, it may be difficult to implement compatibility and dispersing properties of metal pigments, and if the content is excessive, dispersing properties of metal pigments may be deteriorated due to poor appearance due to peeling and gas formation on the surface. .

On the other hand, in the present invention, when polyethylene wax or polypropylene wax is used as the internal lubricant, gas may be induced in injection, extrusion and processing conditions due to low molecular weight, and this may lead to deterioration of metallic pigment dispersion characteristics, so the weight average It is preferable to use those having a molecular weight of 5,000 to 10,000 g/mol, more preferably 6,000 to 8,000 g/mol.

(D) metallic pigment

In the present invention, the metallic pigment is added to polycarbonate and polycyclohelsilenedimethylene terephthalate alloy and used to express various colors of the final polycarbonate resin composition, and is not particularly limited as such metallic pigments, such as aluminum, copper, Zinc, titanium, iron nickel, and alloys thereof.

Here, as the metallic pigment, aluminum having an average particle diameter of 5 to 100 μm may be preferably used. In the case of using aluminum of the particle size, not only an oxide layer is formed in the resin composition, but also various colors can be expressed by overlapping metal particles.

The metallic pigment may be included in an amount of 0.01 to 5% by weight, preferably 0.05 to 3% by weight, more preferably 0.2 to 1% by weight in the total resin composition. When the content of the metal pigment is less than a certain level, color expression may be limited, and when the content is excessive, the dispersion characteristics of the metal pigment may deteriorate.

The polycarbonate resin composition according to the present invention may further include an additive suitable for its intended use or effect. For example, by adding a release agent, an anti-drip agent, an antioxidant, a colorant, etc., it can be applied for various purposes.

Hereinafter, a specific example according to the present invention will be described.

First, specifications of components including polycarbonate resins used in Examples and Comparative Examples of the present invention are as follows.

(A) Polycarbonate (PC) resin

A bisphenol A type polycarbonate (PC-1100S, Lotte Chemical) having a weight average molecular weight of 33,000 and a melt index (300°C, 1.2 kgf) of 10 g/10min was used.

(B) Polycyclohexylenedimethylene terephthalate (PCT) resin

PCT resin (SKYPURA 3402, SK Chemicals) having an intrinsic viscosity (IV) of 0.7 dl/g was used.

(C) Polybutylene terephthalate (PBT)

Polybutylene terephthalate (PBT) resin (Kanghui Petrochemical) having an intrinsic viscosity (IV) of 1.1 dl/g was used.

(D) Polyethylene terephthalate (PET)

Polyethylene terephthalate (PET) resin (Lotte Chemical) having an intrinsic viscosity (IV) of 0.8 dl/g was used.

(E-1) Internal lubricant

Polyethylene wax (Hi-wax 800P, Mitsui chemical) having a weight average molecular weight (Mw) of 8,000 g/mol was used.

(E-2) Internal lubricant

Polyethylene wax (Hi-wax 720P, Mitsui chemical) having a weight average molecular weight (Mw) of 7,200 g/mol was used.

(E-3) Internal lubricant

Polyethylene wax (Hi-wax 400P, Mitsui chemical) having a weight average molecular weight (Mw) of 4,000 g/mol was used.

(E-4) Internal lubricant

Polyethylene wax (Hi-wax 320P, Mitsui chemical) having a weight average molecular weight (Mw) of 3,000 g/mol was used.

(E-5) Internal lubricant

Polyethylene wax (Hi-wax 110P, Mitsui chemical) having a weight average molecular weight (Mw) of 1,000 g/mol was used.

(F) metallic pigment

As a metallic pigment, aluminum powder having an average particle diameter of 20 to 30 μm was used.

Example 1

(A) 79.3% by weight of polycarbonate resin, (B) 20% by weight of PCT resin, (E-1) 0.2% by weight of internal lubricant, and (F) 0.5% by weight of metal pigment were quantitatively mixed and mixed, 270°C to 300°C The thermoplastic resin composition was made into chips using a twin-screw extruder heated with a hot air dryer, and dried at 110° C. for 4 hours, and then the specimen was injection-molded using a mold for making a specimen.

Examples 2 to 9 and Comparative Examples 1 to 3

In Example 1, a specimen was molded in the same manner as in Example 1, except that the components (A) to (F) were adjusted to the content of Table 1 below.

Test example

For the specimens according to the Examples and Comparative Examples, the melt index, tensile strength, elongation, heat resistance, chemical resistance, light transmittance and gloss uniformity were measured according to the following method, and the results are shown in Table 2 below.

[How to measure]

(1) Melt Index

According to ASTM D1238, it was measured under the condition of 2.16kg load at 250°C.

(2) Tensile strength and elongation

A specimen for measurement was made according to ASTM D638, and tensile strength and elongation were measured using a universal testing machine.

(3) Heat resistance (heat deflection temperature, HDT)

A specimen for measurement was made according to ASTM D648 and the heat resistance was measured using a heat resistance tester.

(4) Chemical resistance evaluation

After injecting the manufactured pellets at an injection temperature of 260°C using an injection machine, adjust the condition of the injected tensile strength specimen for 24 hours under conditions of 23±2°C and 50±5% relative humidity, and follow the method below. Evaluation was performed.

① The chemical resistance test fixture was manufactured with a critical strain of 1.0%, and the tensile specimen was fixed with the test fixture.

② Sunscreen (SPF 50) and fragrance (general product sold for automobiles) were applied to the tensile specimen for 1 minute, respectively, and then left at 23±2℃ for 168 hours.

③ After 168 hours elapsed at 23±2℃, the tensile specimen was removed from the test fixture and left at 23±2℃ for about 1 to 2 hours.

④ After leaving for 1 to 2 hours as above, the tensile properties of each specimen to which the sunscreen and fragrance were applied were evaluated.

⑤ Chemical resistance When the tensile properties before the test are 75% or more, preferably 80% or more, and 50% of the elongation property, preferably 55% or more, the chemical resistance was evaluated as excellent.

(5) light transmittance

According to ASTM D1003, a measurement specimen (3mm) was prepared and the light transmittance was measured.

(6) Gloss uniformity (metal pigment dispersibility) evaluation

A specimen (150×150×2.5 mm) injected at an injection temperature of 260°C using an injection machine was adjusted for 24 hours under conditions of 23±2°C and 50±5% relative humidity. After measuring the glossiness using a gloss meter (angle 60°) for 5 points (each corner part and center part), the average value and the variance value were calculated. When the dispersion value was within 5, it was evaluated that the metallic pigment was uniformly dispersed on the surface. For example, in the case of FIG. 1, since the Gloss values of the measurement sites are 89, 88, 88, 90, and 84, respectively, the average value is 87.8 and the variance value is 4.16.

Referring to Table 2, when a metal pigment is applied to a polycarbonate resin and a polycyclohexylenedimethylene terephthalate resin alloy according to the present invention, by containing an internal lubricant of a specific composition, the dispersibility of the metal pigment while maintaining excellent chemical resistance. It can be seen that it is possible to realize high-quality appearance characteristics by providing uniformity to the metallic color of the surface by improving.

On the other hand, when the internal lubricant is not included (Comparative Example 1), the dispersibility of the metallic pigment is significantly lowered, and when a general PBT resin or PET resin is used as an alloy resin other than a PCT resin even if an internal lubricant of a specific composition is included. In (Comparative Examples 2 and 3), it can be seen that the dispersibility of the metallic pigment is relatively good, but the chemical resistance, transparency, and heat resistance are significantly reduced.

However, when the content of a specific internal lubricant is not within the preferred range (Example 5), the metal pigment dispersibility may not reach the expected level, and even when the content is relatively excessive (Example 6), the metal pigment dispersion It can be seen that the characteristics are somewhat deteriorated, and this is considered to be due to the appearance defect of peeling and gas formation on the surface.

In addition, it can be seen that even when the molecular weight of a specific internal lubricant is relatively low (Examples 7 to 9), the dispersion properties of the metal pigment are somewhat deteriorated, and this is believed to be because gas was induced during processing such as injection due to the low molecular weight. .

The preferred embodiments of the present invention have been described in detail above. The description of the present invention is for illustration only, and those of ordinary skill in the art to which the present invention pertains will be able to understand that other specific forms can be easily modified without changing the technical spirit or essential features of the present invention.

Therefore, the scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning, scope, and equivalent concepts of the claims are included in the scope of the present invention. It must be interpreted.

Claims (3)

(A) 60 to 89% by weight of a polycarbonate resin;
(B) 10 to 39% by weight of polycyclohexylenedimethylene terephthalate resin;
(C) 0.01-3% by weight of internal lubricant; And
(D) 0.01-5% by weight of metal pigment;
Including,
The internal lubricant is a polyethylene wax or a polypropylene wax, a polycarbonate resin composition, characterized in that the weight average molecular weight of 5,000 to 10,000 g / mol. delete The method of claim 1,
The polycarbonate resin composition has a light transmittance (ASTM D1003, 3 mm thick injection specimen, based on no pigment added) of 65% or more, and a gloss uniformity of less than 5 according to the following measurement method:
[Method of measuring gloss uniformity]
A specimen (150×150×2.5 mm) injected with the resin composition at an injection temperature of 260° C. was adjusted for 24 hours under conditions of 23±2° C. and 50±5% relative humidity, and then 5 points (each corner and center Part), using a gloss meter (angle 60°) to measure the gloss and calculate the variance.

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