Polycarbonate resin composition having excellent optical properties and molded article containing the same

Abstract

The present invention relates to a polycarbonate resin composition having excellent optical properties and a molded article containing the same. More specifically, the present invention relates to a polycarbonate resin composition which contains polycarbonate as a base resin and a polyalkylene glycol adduct of an anhydrosugar alcohol, which is a biomass-derived substance, as a plasticizer component, and which has excellent optical properties and processability as well as excellent mechanical properties such as tensile strength and heat resistance, and a molded article containing the same.

Description

Technical Field

[0001] The present invention relates to a polycarbonate resin composition having excellent optical properties and a molded article containing the same. More specifically, the present invention relates to a polycarbonate resin composition containing polycarbonate as a base resin and a polyalkylene glycol adduct of anhydro sugar alcohol, which is a biomass-derived substance, as a plasticizer component, and having excellent optical properties and processability, as well as excellent mechanical properties such as tensile strength and heat resistance, and a molded article containing the same.

Background Art

[0002] In order to manufacture light-guides used in automobile headlamps and the like, lighting components and housings of various electronic devices with a uniform thickness, a resin having a high melt index is required, and at the same time, a resin having excellent transmittance, low yellowness index characteristics, good impact resistance, and the like is required. In recent years, consideration for the environment has become important, and the development of a resin that simultaneously satisfies the above physical properties and improves transparency has been demanded.

[0003] Patent Document 1 discloses a composition containing polycarbonate and a carboxylic acid ester of isosorbide, in which the rheology and optical properties are improved. However, the disclosed material has a transmittance of only 89% at a thickness level of 4 mm and a YI value exceeding 2, and thus has insufficient physical properties for use as a light-guide. In addition, Patent Document 2 discloses a [poly(isosorbide carbonate and aromatic carbonate - aromatic carbonate)] - [polycarbonate] block copolymer that is environmentally friendly, has a high biomass-derived substance content, and has an excellent balance of physical properties such as color, moldability, heat resistance, and impact resistance. However, the disclosed material is not intended to achieve physical properties for use as a light-guide, such as improving optical properties.

[0004] Therefore, in order to solve the problems of the prior art, there has been a demand for the development of an environmentally friendly resin composition that has a high transmittance, a low yellowness index, excellent mechanical properties such as moldability and tensile strength, and heat resistance, and is particularly suitable for light guide applications.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention solves the above-mentioned problems of the prior art, and provides an environmentally friendly polycarbonate resin composition having excellent optical properties (i.e., high transmittance and low yellowness index) and processability as compared with conventional polycarbonate resin compositions, and excellent mechanical properties such as tensile strength and heat resistance, and a molded article (particularly, a light guide) containing the same.

Means for Solving the Problems

[0007] To achieve the above object, one aspect of the present invention provides a thermoplastic resin composition comprising a polycarbonate resin as a base resin; and a polyalkylene glycol adduct of anhydro sugar alcohol as a plasticizer component.

[0008] Another aspect of the present invention provides a molded article, preferably a light guide, containing the thermoplastic resin composition according to the present invention.

Effects of the Invention

[0009] The thermoplastic resin composition according to the present invention is environmentally friendly and has excellent optical properties (i.e., high transmittance and low yellowness index) and processability compared to conventional polycarbonate resin compositions, and also has excellent mechanical properties such as tensile strength and heat resistance. Therefore, molded articles containing this can be suitably used for optical applications in various industrial fields, and in particular, can be extremely suitably used for applications as light guides (more specifically, light guides for automobiles, and even more specifically, light guides for automobile headlamps).

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described in more detail.

[0011] The thermoplastic resin composition of the present invention contains a polycarbonate resin as a base resin; and a polyalkylene glycol adduct of anhydro sugar alcohol as a plasticizer component.

[0012] (1) Base resin: Polycarbonate resin The polycarbonate resin contained as a base resin in the thermoplastic resin composition of the present invention may be an aromatic polycarbonate resin, and its type is not particularly limited as long as the technical idea of the present invention can be realized. Any of the thermoplastic aromatic polycarbonate resins conventionally used in this field can be used.

[0013] In one embodiment, the aromatic polycarbonate resin can be produced from a dihydric phenol, a carbonate precursor, and a molecular weight regulator.

[0014] The dihydric phenols are one of the monomers constituting the aromatic polycarbonate resin, and the following formula (1)

Chemical formula

[0015] Non-limiting examples of the divalent phenols include bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)naphthylmethane, bis(4-hydroxyphenyl)-(4-isobutylphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1-ethyl-1,1-bis(4-hydroxyphenyl)propane, 1-phenyl-1,1-bis(4-hydroxyphenyl)ethane, 1-naphthyl-1,1-bis(4-hydroxyphenyl)ethane, 1,2-bis(4-hydroxyphenyl)ethane, 1,10-bis(4-hydroxyphenyl)decane, 2-methyl-1,1-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), etc., and preferably bisphenol A.

[0016] The carbonate precursor is another monomer that constitutes the aromatic polycarbonate resin. Non-limiting examples thereof include carbonyl chloride (phosgene), carbonyl bromide, bis-haloformate, diphenyl carbonate, dimethyl carbonate, etc., and preferably carbonyl chloride (phosgene).

[0017] As the molecular weight regulator, a conventionally known compound, that is, a monofunctional compound equivalent to the monomers used in the production of thermoplastic aromatic polycarbonate resins can be used. Non-limiting examples of the molecular weight regulator include phenol-based derivatives (e.g., p-isopropylphenol, p-tert-butylphenol (PTBP), p-cumyl phenol, p-isooctylphenol, p-isononylphenol, etc.), aliphatic alcohols, etc. Preferably, p-tert-butylphenol (PTBP) is mentioned.

[0018] Examples of the aromatic polycarbonate resin produced from such dihydric phenols, carbonate precursors, and molecular weight regulators include linear polycarbonate resins, branched polycarbonate resins, copolycarbonate resins, and polyester carbonate resins, etc. In the present invention, these can be used alone or in a mixture of two or more.

[0019] In one embodiment, the viscosity-average molecular weight (Mv, measured in a methylene chloride solution at 25°C) of the aromatic polycarbonate resin may be 15,000 to 40,000, more specifically 17,000 to 30,000, and even more specifically 20,000 to 30,000. When the viscosity-average molecular weight of the aromatic polycarbonate resin is less than 15,000, the mechanical properties such as impact strength and tensile strength may decrease. Conversely, when the viscosity-average molecular weight of the aromatic polycarbonate resin exceeds 40,000, problems may occur in the processing of the resin due to an increase in solution viscosity.

[0020] In one embodiment, with respect to 100 parts by weight of the total amount of the thermoplastic resin composition of the present invention, the amount of the polycarbonate-based resin may be, for example, 15 parts by weight or more, 20 parts by weight or more, 30 parts by weight or more, 40 parts by weight or more, 45 parts by weight or more, 50 parts by weight or more, 55 parts by weight or more, 60 parts by weight or more, 70 parts by weight or more, 80 parts by weight or more, or 90 parts by weight or more, and may be 99.9 parts by weight or less, 99.8 parts by weight or less, 99.7 parts by weight or less, 99.6 parts by weight or less, 99.5 parts by weight or less, 99.4 parts by weight or less, 99.3 parts by weight or less, 99.2 parts by weight or less, 99.1 parts by weight or less, or 99 parts by weight or less.

[0021] (2) Plasticizer component: Polyalkylene glycol adduct of anhydro sugar alcohol The polyalkylene glycol adduct of anhydro sugar alcohol contained as a plasticizer component in the thermoplastic resin composition of the present invention is a compound having a form in which a polyalkylene glycol substituent is bonded to the terminal hydroxy group of anhydro sugar alcohol.

[0022] Anhydro sugar alcohol can be produced by a dehydration reaction of a hydrogenated sugar derived from natural products. Hydrogenated sugar (also referred to as "sugar alcohol") means a compound obtained by adding hydrogen to the reducing terminal group of saccharides. Generally, it has the formula HOCH 2 (CHOH) n CH 2 OH (where n is an integer from 2 to 5), and depending on the number of carbon atoms, it is classified into tetritol, pentitol, hexitol, and heptitol (having 4, 5, 6, and 7 carbon atoms respectively). Among them, hexitols having 6 carbon atoms include sorbitol, mannitol, iditol, galactitol, etc., and sorbitol and mannitol are substances with particularly great utility.

[0023] The anhydro sugar alcohol may be a monoanhydro sugar alcohol, a dianhydro sugar alcohol, or a mixture thereof, and is not particularly limited, but a dianhydro sugar alcohol can be used.

[0024] The monoanhydro sugar alcohol is an anhydro sugar alcohol obtained by removing one water molecule from within the hydrogenated sugar, and has the form of a tetraol having four hydroxy groups in the molecule. In the present invention, the type of the monoanhydro sugar alcohol is not particularly limited, and may preferably be a monoanhydro sugar hexitol, and more specifically, may be 1,4-anhydrohexitol, 3,6-anhydrohexitol, 2,5-anhydrohexitol, 1,5-anhydrohexitol, 2,6-anhydrohexitol, or a mixture of two or more thereof.

[0025] The dianhydro sugar alcohol is an anhydro sugar alcohol obtained by removing two water molecules from within the hydrogenated sugar, has the form of a diol having two hydroxy groups in the molecule, and can be produced using hexitol derived from starch. Since the dianhydro sugar alcohol is an environmentally friendly substance using renewable natural resources as raw materials, it has been attracting attention for a long time, and research on its production has been underway. Research on its production method has been continuously carried out with great interest. Among such dianhydro sugar alcohols, isosorbide produced from sorbitol currently has the widest industrial application range.

[0026] In the present invention, the type of the dianhydro sugar alcohol is not particularly limited, and may preferably be a dianhydrohexitol, and more specifically, may be 1,4:3,6-dianhydrohexitol. The 1,4:3,6-dianhydrohexitol may be isosorbide, isomannide, isoidide, or a mixture of two or more thereof. In a preferred embodiment of the present invention, the anhydro sugar alcohol may be isosorbide.

[0027] In one embodiment, the polyalkylene glycol may be polyethylene glycol, polypropylene glycol, polybutylene glycol, or a combination thereof.

[0028] In one embodiment, the molecular weight (weight average molecular weight) of the polyalkylene glycol may be 500 to 5000 g / mol, more specifically, it may be 1000 to 4000 g / mol, but is not limited thereto.

[0029] In one embodiment, the polyalkylene glycol adduct of the anhydro sugar alcohol has the following formula (2) H-[X] p -[O-A-O]-[X’] q -H (2) (In the formula, [O-A-O] is the part derived from anhydro sugar alcohol obtained by removing hydrogen atoms from the hydroxy groups at both ends of the anhydro sugar alcohol, and H-[X] p is independently H-[O-alkylene] p and [X’] q -H is independently [alkylene-O] q -H, and p and q each independently represent an integer of 2 to 15.) can be represented. More specifically, in the formula (2), the anhydro sugar alcohol may be isosorbide, also, the alkylene may be a linear alkylene having 2 to 8 carbon atoms or a branched alkylene having 3 to 8 carbon atoms, more specifically, ethylene, propylene, butylene or a combination thereof may be used, p and q may each independently represent an integer of 2 to 12.

[0030] In one embodiment, the polyalkylene glycol adduct of the anhydro sugar alcohol has the following formula (3)

Chemical formula

[0031] In one embodiment, the polyalkylene glycol adduct of the anhydro sugar alcohol can be obtained, for example, as shown in the following reaction scheme, by reacting a hydroxy group at both ends or one end (preferably both ends) of the anhydro sugar alcohol with an alkylene oxide in the presence of a catalyst (for example, a base catalyst), so that the hydrogen of the hydroxy group at both ends or one end (preferably both ends) of the anhydro sugar alcohol is substituted with a hydroxyalkyl group in the ring-opened form of the alkylene oxide. <Reaction Scheme> [Chemical formula]

[0032] In one embodiment, the alkylene oxide may be a linear alkylene oxide having 2 to 8 carbon atoms or a branched alkylene oxide having 3 to 8 carbon atoms, and more specifically, ethylene oxide, propylene oxide, butylene oxide or a combination thereof.

[0033] In one embodiment, the anhydro sugar alcohol may be treated with an acid component before reacting with an alkylene oxide, and the reaction of the anhydro sugar alcohol treated with the acid component and the alkylene oxide may be carried out, for example, in a high-pressure reactor capable of pressurization (for example, pressurization of 3 MPa or more), in the presence of a base catalyst (for example, hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide or hydroxides of alkaline earth metals such as calcium hydroxide), at a high temperature (for example, 100 °C to 180 °C, or 120 °C to 160 °C), for example, for 1 hour to 8 hours or 2 hours to 4 hours, but is not limited thereto. The reaction molar ratio of the anhydro sugar alcohol and the alkylene oxide may be, for example, 1 mol or more, 2 mol or more, or 3 mol or more, and may also be 30 mol or less, 20 mol or less, 15 mol or less, or 12 mol or less. For example, it may be 1 mol to 30 mol, preferably 2 to 20 mol, and more preferably 3 to 15 mol, but is not limited thereto.

[0034] In one embodiment, based on 100 parts by weight of the total amount of the thermoplastic resin composition of the present invention, the polyalkylene glycol adduct of the anhydro sugar alcohol as a plasticizer component may be contained in an amount of, for example, 0.06 part by weight or more, 0.1 part by weight or more, 0.2 part by weight or more, 0.3 part by weight or more, 0.4 part by weight or more, 0.5 part by weight or more, 0.6 part by weight or more, 0.7 part by weight or more, 0.8 part by weight or more, 0.9 part by weight or more, or 1 part by weight or more, and may also be contained in an amount of 2.49 parts by weight or less, 2.45 parts by weight or less, 2.4 parts by weight or less, 2.35 parts by weight or less, 2.3 parts by weight or less, 2.25 parts by weight or less, 2.2 parts by weight or less, 2.15 parts by weight or less, 2.1 parts by weight or less, 2.05 parts by weight or less, or 2 parts by weight or less. If the content of the polyalkylene glycol adduct of the anhydro sugar alcohol in 100 parts by weight of the total amount of the thermoplastic resin composition is less than 0.06 part by weight, the transmittance may decrease and the yellowness index may increase, and high transmittance may not be achieved. Conversely, if the content exceeds 2.49 parts by weight, the plasticizer in the composition may crystallize and the optical properties may deteriorate.

[0035] (3) Optional additives In the thermoplastic resin composition of the present invention, other additives can be added as necessary within the range that can achieve the object of the present invention in addition to the above components. The types and contents of the other additives can be easily selected by those skilled in the art according to various purposes. In one embodiment, an inorganic filler, a lubricant, an antioxidant, a light stabilizer, a hydrolysis stabilizer, a release agent, a colorant, an ultraviolet stabilizer, an antistatic agent, a conductivity-imparting agent, a magnetism-imparting agent, a crosslinking agent, an antibacterial agent, a processing aid, an abrasion-resistant agent, and a coupling agent can be added to the composition alone or in combination of two or more.

[0036] As the antioxidant, a phenolic, phosphite, thioether, or amine-based antioxidant can be used. As the release agent, a fluorine-containing polymer, silicone oil, metal salt of stearic acid, metal salt of montanic acid, montanic acid ester wax, or polyethylene wax can be used. Also, as the ultraviolet stabilizer, benzophenone or benzotriazole and amine-based ultraviolet stabilizers can be used. As the colorant, a dye or a pigment can be used.

[0037] In addition, as other additives, commercially available general ones can be used. The content of the other additives is not particularly limited, and may be 1 to 5 parts by weight, more specifically 2 to 5 parts by weight, based on 100 parts by weight of the total amount of the thermoplastic resin composition of the present invention. However, it is not limited thereto.

[0038] The thermoplastic resin composition according to the present invention uses anhydro sugar alcohol, which is a biomass-derived substance, so it is environmentally friendly, has excellent optical properties (i.e., high transmittance and low yellowness index) and processability compared to conventional polycarbonate resin compositions, and also has excellent mechanical properties such as tensile strength and heat resistance. Therefore, molded articles containing this can be suitably used for optical applications in various industries. In particular, it can be extremely suitably used for applications as a light guide (more specifically, a light guide for automobiles, and even more specifically, a light guide for automobile headlamps).

[0039] Accordingly, according to another aspect of the present invention, a molded article containing the thermoplastic resin composition of the present invention is provided. The molded article may be an extruded article or an injection molded article of the thermoplastic resin composition of the present invention. In a preferred embodiment, the molded article may be a light guide.

[0040] The present invention will be described in more detail through the following examples and comparative examples. However, the scope of the present invention is not limited thereto.

Examples

[0041] The components used in the examples and comparative examples are as follows. (A) Polycarbonate resin: 3017 PJ manufactured by Samyang Corporation (B) Polycarbonate resin: 1600R manufactured by Lotte Chemical Corporation (C) [Poly(isosorbide carbonate - aromatic carbonate)] - [polycarbonate] block copolymer (copolymer manufactured by the method disclosed in Korean Patent No. 10 - 1608411) (D) Polyethylene glycol (PEG) (D - 1) PEG - 1000 (molecular weight: 1000 g / mol) (D - 2) PEG - 2000 (molecular weight: 2000 g / mol) (D - 3) PEG - 4000 (molecular weight: 4000 g / mol) (E) Polypropylene glycol (PPG) (E - 1) PPG - 1000 (molecular weight: 1000 g / mol) (E - 2) PPG - 2000 (molecular weight: 2000 g / mol) (E - 3) PPG - 4000 (molecular weight: 4000 g / mol) (F) Polybutylene glycol (PBG) (F - 1) PBG - 1000 (molecular weight: 1000 g / mol) (F - 2) PBG - 2000 (molecular weight: 2000 g / mol) (F-3) PBG-4000 (Molecular weight: 4000 g / mol) (G) Poly(ethylene adipate) (AD2000) (Molecular weight: 8000 g / mol) (H) Fatty acid diester of isosorbide (ID37, manufactured by Roquette Pierre) (I) Polyethylene glycol adduct of isosorbide (I-1) EI-1000 (Molecular weight of polyethylene glycol: 1000 g / mol) (I-2) EI-2000 (Molecular weight of polyethylene glycol: 2000 g / mol) (I-3) EI-4000 (Molecular weight of polyethylene glycol: 4000 g / mol) (J) Polypropylene glycol adduct of isosorbide (J-1) PI-1000 (Molecular weight of polypropylene glycol: 1000 g / mol) (J-2) PI-2000 (Molecular weight of polypropylene glycol: 2000 g / mol) (J-3) PI-4000 (Molecular weight of polypropylene glycol: 4000 g / mol) (K) Polybutylene glycol adduct of isosorbide (K-1) BI-1000 (Molecular weight of polybutylene glycol: 1000 g / mol) (K-2) BI-2000 (Molecular weight of polybutylene glycol: 2000 g / mol) (K-3) BI-4000 (Molecular weight of polybutylene glycol: 4000 g / mol) The polyalkylene glycol adduct of isosorbide was produced by adding an acid-treated isosorbide and the corresponding alkylene oxide in the presence of KOH as a catalyst at 100 °C to 140 °C, cooling and filtering the product, and purifying it using an ion exchange resin.

[0042] After manufacturing the resin compositions with the components and contents of each of the examples and comparative examples shown in Table 1 below, an extrusion molding was carried out using a twin-screw melt kneading extruder with L / D = 48 and Φ = 25 mm under the conditions of a melting temperature of 240 to 260°C, a screw rotation speed of 150 rpm, a first vent pressure of about -600 mmHg, and a self-feeding speed of 20 kg / h. After cooling the extruded strands in water, they were cut with a rotary cutter to produce pellets.

[0043] After heat drying the produced pellets at 80°C to 100°C for 4 hours, injection molding was carried out at a cylinder temperature of 250°C to 280°C and a molding temperature of 80°C to produce test pieces. The physical properties of each of the produced test pieces were measured by the methods described below, and the results are shown in Table 1 below. The physical properties of each of the produced test pieces were measured and evaluated by the following methods. (1) Tensile strength: Evaluated based on ASTM D638. (2) Flexural strength and modulus of elasticity: Evaluated based on ASTM D790. (3) Impact strength: Evaluated based on ASTM D256 (thickness 1 / 8 inch, notch - Izod). (4) Heat distortion temperature: Based on ASTM D648, evaluated under a load of 18.6 kg / cm 2 of load. (5) Melt index: Measured based on ASTM D1238 under the conditions of a temperature of 300°C and a load of 1.2 kgf. (6) Transmittance: Using a Gardneri Haze Meter manufactured by BYK, the transmittance (%) value was measured for a rectangular test piece (90×80×6.4 mm) based on ASTM D1003. (7) YI (yellowness index): Using a spectroscopic colorimeter CI 7800SE manufactured by X-rite, the YI value was measured for a rectangular test piece (90×80×6.4 mm).

Table 1-1

Table 1-2

Table 1-3

[0044] As shown in Table 1 above, in the case of Examples 1-1 to 3-5 according to the present invention, all of them have excellent optical properties (i.e., high transmittance and low yellowness index) and excellent processability (high melt index), and also have excellent mechanical properties such as tensile strength, flexural strength, flexural modulus, and impact strength, and heat resistance, and it was possible to ensure well-balanced physical properties.

[0045] Specifically, Examples 1-1 to 3-5, which are polycarbonate compositions excellent in the optical properties of the present invention, maintain mechanical physical properties and optical properties suitable for use as automotive light guides. In particular, the compositions of Examples 3-4 and 3-5 exhibit optical properties very suitable for parts for such applications, and it was confirmed that the mechanical physical properties and optical properties that can be used as automotive headlamp light guides have been improved.

[0046] However, in the case of the comparative examples, one or more of the above measurement and evaluation items were poor. That is, when the polyalkylene glycol adduct of anhydro sugar alcohol is not used as the plasticizer component, that is, in Comparative Examples 1-1 to 3-5 using simple polyalkylene glycol, Comparative Example 4-1 using poly(ethylene adipate), and Comparative Example 4-2 using the fatty acid diester of isosorbide, it was confirmed that the mechanical properties decreased because the alicyclic functional group that imparts rigidity was absent, or the optical properties were very poor because there was no polyalkylene glycol that imparts compatibility with the resin.

Claims

1. A polycarbonate resin as a base resin; and A polyalkylene glycol adduct of anhydro sugar alcohol as a plasticizer component; comprising A thermoplastic resin composition, wherein the molecular weight of the polyalkylene glycol is 500 to 5000 g / mol.

2. The thermoplastic resin composition according to Claim 1, wherein the polycarbonate resin is a thermoplastic aromatic polycarbonate resin.

3. The thermoplastic resin composition according to Claim 1, wherein the anhydro sugar alcohol is isosorbide.

4. The thermoplastic resin composition according to Claim 1, wherein the polyalkylene glycol is polyethylene glycol, polypropylene glycol, polybutylene glycol, or a combination thereof.

5. The thermoplastic resin composition according to Claim 1, comprising the polyalkylene glycol adduct of anhydro sugar alcohol in an amount of 0.06 parts by weight to 2.49 parts by weight based on 100 parts by weight of the total amount of the thermoplastic resin composition.

6. A molded article comprising the thermoplastic resin composition according to any one of Claims 1 to 5.

7. The molded article according to Claim 6, which is a light guide. ​ ​ ​ ​ ​

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