Patent Application
20240254330
The present invention relates to a thermoplastic resin composition and a molded article produced therefrom. More particularly, the present invention relates to a thermoplastic resin composition having good properties in terms of metal adhesion, impact resistance, rigidity, thermal stability, and balance therebetween, and a molded article produced therefrom.
As engineering plastics, a polyester resin and a blend of a polyester resin and a polycarbonate resin exhibit useful properties and are applied to various fields including interior and exterior materials for electric/electronic products. However, the polyester resin has problems of low crystallization rate, low mechanical strength, and low impact strength.
Thus, various attempts have been made to improve mechanical properties including impact resistance and rigidity of the polyester resin by adding additives such as inorganic fillers to the polyester resin. For example, polybutylene terephthalate (PBT) resins reinforced by inorganic fillers, such as glass fibers, are frequently used as materials for automotive parts and the like. However, such materials have a limitation in improvement in impact resistance, rigidity, and the like and exhibit deterioration in metal adhesion and the like.
Therefore, there is a need for development of a thermoplastic resin composition having good properties in terms of metal adhesion, impact resistance, rigidity, thermal stability, and balance therebetween.
The background technique of the present invention is disclosed in Korean Patent Registration No. 10-0709878.
It is an object of the present invention to provide a thermoplastic resin composition having good properties in terms of metal adhesion, impact resistance, rigidity, thermal stability, and balance therebetween.
It is another object of the present invention to provide a molded article formed from the thermoplastic resin composition.
The above and other objects of the present invention can be achieved by embodiments of the present invention described below.
The present invention provides a thermoplastic resin composition having good properties in terms of metal adhesion, impact resistance, rigidity, thermal stability, and balance therebetween and a molded article formed therefrom.
Hereinafter, embodiments of the present invention will be described in detail.
A thermoplastic resin composition according to the present invention comprises: (A) a polyester resin; (B) a polycarbonate resin; (C) flat glass fibers; (D) an epoxy-modified olefin polymer; and (E) a maleic anhydride-modified polyolefin.
As used herein to represent a specific numerical range, “a to b” means “≥a and ≤b”.
The polyester resin according to the present invention may be a polyester resin used in typical thermoplastic resin compositions. For example, the polyester resin may be obtained by polycondensation of a dicarboxylic acid component with a diol component, wherein: the dicarboxylic acid component may include aromatic dicarboxylic acids, such as terephthalic acid (TPA), isophthalic acid (IPA), 1,2-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 1,6-naphthalene dicarboxylic acid, 1,7-naphthalene dicarboxylic acid, 1,8-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalenedicarboxylic acid and the like, aromatic dicarboxylates, such as dimethyl terephthalate (DMT), dimethyl isophthalate, dimethyl-1,2-naphthalate, dimethyl-1,5-naphthalate, dimethyl-1,7-naphthalate, dimethyl-1,7-naphthalate, dimethyl-1,8-naphthalate, dimethyl-2,3-naphthalate, dimethyl-2,6-naphthalate, dimethyl-2,7-naphthalate and the like; and the diol component may include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2,2-dimethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,5-pentanediol, 1,6-hexanediol, cycloalkylene diol, and the like.
In some embodiments, the polyester resin may include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), polycyclohexylenedimethylene terephthalate (PCT), and combinations thereof. Preferably, the polyester resin includes polybutylene terephthalate, polyethylene terephthalate, polycyclohexylenedimethylene terephthalate, and combinations thereof.
In some embodiments, the polyester resin may have an intrinsic viscosity [n] of about 0.5 dL/g to about 1.5 dL/g, for example, about 0.7 dL/g to about 1.3 dL/g, as measured in accordance with ASTM D2857. Within this range, the thermoplastic resin composition can have good mechanical properties.
The polycarbonate resin according to the present invention serves to improve impact resistance, appearance characteristics and the like of the thermoplastic resin composition and may be a polycarbonate resin used in typical thermoplastic resin compositions. For example, the polycarbonate resin may be an aromatic polycarbonate resin prepared by reacting diphenols (aromatic diol compounds) with a precursor, such as phosgene, halogen formate, carbonic diester, and the like.
In some embodiments, the diphenols may include, for example, 4,4′-biphenol, 2,2-bis(4-hydroxyphenyl)propane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(3-chloro-4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, and 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, without being limited thereto. For example, the diphenols may be 2,2-bis-(4-hydroxyphenyl)propane, 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, or 1,1-bis(4-hydroxyphenyl)cyclohexane, specifically 2,2-bis(4-hydroxyphenyl)propane, which is also referred to as bisphenol A.
In some embodiments, the polycarbonate resin may be a branched polycarbonate resin. For example, the polycarbonate resin may be a branched polycarbonate resin prepared by adding about 0.05 mol % to about 2 mol % of a tri- or higher polyfunctional compound, specifically a tri- or higher valent phenol group-containing compound, based on the total number of moles of the diphenols used in polymerization.
In some embodiments, the polycarbonate resin may be a homopolycarbonate resin, a copolycarbonate resin, or a blend thereof. The polycarbonate resin may be partially or completely replaced by an aromatic polyester-carbonate resin obtained by polymerization in the presence of an ester precursor, for example, a bifunctional carboxylic acid.
In some embodiments, the polycarbonate resin may have a weight average molecular weight (Mw) of about 20,000 g/mol to about 50,000 g/mol, for example, about 25,000 g/mol to about 40,000 g/mol, as measured by gel permeation chromatography (GPC). Within this range, the thermoplastic resin composition can have good properties in terms of impact resistance, fluidity (processability), and the like.
In some embodiments, the polycarbonate resin may be present in an amount of about 7 parts by weight to about 25 parts by weight, for example, about 10 parts by weight to about 20 parts by weight, relative to about 100 parts by weight of the polyester resin. If the content of the polycarbonate resin is less than about 7 parts by weight relative to about 100 parts by weight of the polyester resin, the thermoplastic resin composition can exhibit deterioration in metal adhesion, impact resistance, appearance, and the like, whereas, if the content of the polycarbonate resin exceeds about 25 parts by weight relative to about 100 parts by weight of the polyester resin, the thermoplastic resin composition can exhibit deterioration in metal adhesion, rigidity, and the like.
The flat glass fibers according to the present invention serves to improve rigidity, impact resistance, metal adhesion and the like of the thermoplastic resin composition comprising the polyester resin and the polycarbonate resin together with the epoxy-modified olefin polymer and the maleic anhydride-modified polyolefin.
In some embodiments, the flat glass fibers may have a rectangular or elliptical cross-section. In addition, the flat glass fibers may have a cross-sectional aspect ratio (cross-sectional major diameter/cross-sectional minor diameter) of about 1.5 to about 10, a minor diameter of about 2 μm to about 10 μm, and a pre-processing length of about 2 mm to about 20 mm, as measured using a scanning electron microscope (SEM). Within these ranges of aspect ratio, minor diameter, and pre-processing length, the thermoplastic resin composition can have improved properties in terms of rigidity, processability, and the like.
In some embodiments, the flat glass fibers may be treated with a typical surface treatment agent.
In some embodiments, the flat glass fibers may be present in an amount of about 30 parts by weight to about 110 parts by weight, for example, about 50 parts by weight to about 100 parts by weight, relative to about 100 parts by weight of the polyester resin. If the content of the flat glass fibers is less than about 30 parts by weight relative to about 100 parts by weight of the polyester resin, the thermoplastic resin composition can exhibit deterioration in impact resistance, rigidity, thermal stability, and the like, whereas, if the content of the flat glass fibers exceeds about 110 parts by weight relative to about 100 parts by weight of the polyester resin, the thermoplastic resin composition can exhibit deterioration in metal adhesion, impact resistance, appearance, and the like.
The epoxy-modified olefin polymer according to the present invention serves to improve metal adhesion, impact resistance, rigidity, thermal stability and the like of the thermoplastic resin composition comprising the polyester resin and the polycarbonate resin together with the flat glass fibers and the epoxy-modified olefin polymer, and may be prepared by polymerization of an epoxy compound containing a reactive functional group with an olefin polymer (an olefin homopolymer, an olefin copolymer, an alkylene-alkyl (meth)acrylate copolymer, and the like).
In some embodiments, the epoxy compound may include glycidyl (meth)acrylate, allyl glycidyl ether, 2-methylallyl glycidyl ether, and mixtures thereof.
In some embodiments, the olefin polymer may be a homopolymer of alkylene monomers, a copolymer of alkylene monomers, and/or an alkylene-alkyl (meth)acrylate copolymer, wherein the alkylene monomers may include C2 to C10 alkylenes, for example, ethylene, propylene, isopropylene, butylene, isobutylene, octene, and the like.
In some embodiments, the epoxy-modified olefin polymer may include glycidyl (meth)acrylate-modified polyethylene, a glycidyl (meth)acrylate-modified ethylene-butyl acrylate copolymer, a glycidyl (meth)acrylate-modified ethylene-methyl acrylate copolymer, and combinations thereof.
In some embodiments, the epoxy-modified olefin polymer may have a melt-flow index of about 1 g/10 min to about 50 g/10 min, for example, about 2 g/10 min to about 25 g/10 min, as measured at a temperature of 190° C. under a load of 2.16 kg in accordance with ASTM D1238. Within this range, the thermoplastic resin composition can have good properties in terms of impact resistance and the like.
In some embodiments, the epoxy-modified olefin polymer may be present in an amount of about 3 parts by weight to about 13 parts by weight, for example, about 4 parts by weight to about 10 parts by weight, relative to about 100 parts by weight of the polyester resin. If the content of the epoxy-modified olefin polymer is less than about 3 parts by weight relative to about 100 parts by weight of the polyester resin, the thermoplastic resin composition can exhibit deterioration in impact resistance, thermal stability, and the like, whereas, if the content of the epoxy-modified olefin polymer exceeds about 13 parts by weight relative to about 100 parts by weight of the polyester resin, the thermoplastic resin composition can exhibit deterioration in metal adhesion and the like.
In some embodiments, the flat glass fibers and the epoxy-modified olefin polymer may be present in a weight ratio (C:D) of about 1:0.04 to about 1:0.2, for example, about 1:0.04 to about 1:0.15. Within this range, the thermoplastic resin composition can have further improved properties in terms of impact resistance, rigidity, and the like.
The maleic anhydride-modified polyolefin according to the present invention serves to improve metal adhesion, impact resistance, rigidity, thermal stability and the like of the thermoplastic resin composition comprising the polyester resin and the polycarbonate resin together with the flat glass fibers and the epoxy-modified olefin polymer, and may be prepared by polymerization of a polyolefin (an alkylene homopolymer) with maleic anhydride (MAH).
In some embodiments, the polyolefin may be a homopolymer of alkylene monomers, wherein the alkylene monomers may include C2 to C10 alkylenes, for example, ethylene, propylene, isopropylene, butylene, isobutylene, octene, and the like.
In some embodiments, the maleic anhydride-modified polyolefin may include maleic anhydride-modified polypropylene, maleic anhydride-modified polyethylene, maleic anhydride-modified polybutylene, and combinations thereof.
In some embodiments, the maleic anhydride-modified polyolefin may have a melt-flow index of about 5 g/10 min to about 40 g/10 min, for example, about 10 g/10 min to about 15 g/10 min, as measured at a temperature of 230° C. under a load of 2.16 kg in accordance with ASTM D1238. Within this range, the thermoplastic resin composition can have good properties in terms of impact resistance, metal adhesion, and the like.
In some embodiments, the maleic anhydride-modified polyolefin may be present in an amount of about 0.2 parts by weight to about 10 parts by weight, for example, about 0.3 parts by weight to about 5 parts by weight, specifically about 0.4 parts by weight to about 2 parts by weight, relative to about 100 parts by weight of the polyester resin. If the content of the maleic anhydride-modified polyolefin is less than about 0.2 parts by weight relative to about 100 parts by weight of the polyester resin, the thermoplastic resin composition can exhibit deterioration in impact resistance, thermal stability, metal adhesion, and the like, whereas, if the content of the maleic anhydride-modified polyolefin exceeds about 10 parts by weight relative to about 100 parts by weight of the polyester resin, the thermoplastic resin composition can exhibit deterioration in metal adhesion, impact resistance, thermal stability, and the like.
In some embodiments, the epoxy-modified olefin polymer and the maleic anhydride-modified polyolefin may be present in a weight ratio (D:E) of about 1:0.1 to about 1:1, for example, about 1:0.05 to about 1:0.5. If the weight ratio (D:E) is less than about 1:0.1, the thermoplastic resin composition can exhibit deterioration in impact resistance, thermal stability, metal adhesion, and the like, whereas, if the weight ratio (D:E) exceeds about 1:1, the thermoplastic resin composition can exhibit deterioration in impact resistance, thermal stability, metal adhesion, and the like.
The thermoplastic resin composition according to the present invention may further comprise additives used in typical thermoplastic resin compositions. The additives may include, for example, impact modifiers, flame retardants, antioxidants, anti-dripping agents, lubricants, release agents, nucleating agents, antistatic agents, stabilizers, pigments, dyes, and mixtures thereof, without being limited thereto. In the thermoplastic resin composition, the additives may be present in an amount of about 0.001 parts by weight to about 40 parts by weight, for example, about 0.1 parts by weight to about 10 parts by weight, relative to about 100 parts by weight of the polyester resin.
The thermoplastic resin composition according to the present invention may be prepared in pellet form by mixing the aforementioned components, followed by melt extrusion in a typical twin screw extruder at about 240° C. to about 300° C., for example, about 260° C. to about 290° C.
In some embodiments, the thermoplastic resin composition may have a metal adhesion strength of about 35 MPa to about 50 MPa, for example, about 36 MPa to about 48 MPa, as measured with respect to an aluminum-based metal specimen in accordance with ISO 19095.
In some embodiments, the thermoplastic resin composition may have a dart impact strength of about 76 cm to about 120 cm, for example, about 78 cm to about 110 cm, as determined by measuring a height from which dropping a 500 g dart causes cracking of a 2 mm thick specimen in accordance with the DuPont drop test method.
In some embodiments, the thermoplastic resin composition may have a notched Izod impact strength of about 12.5 kgf cm/cm to about 20 kgf cm/cm, for example, about 12.7 kgf cm/cm to about 17 kgf cm/cm, as measured on a ⅛″ thick specimen in accordance with ASTM D256.
In some embodiments, the thermoplastic resin composition may have a flexural modulus of about 80,000 kgf/cm2 to about 140,000 kgf/cm2, for example, about 80,000 kgf/cm2 to about 130,000 kgf/cm2, as measured on a ¼″ thick specimen at a rate of 2.8 mm/min in accordance with ASTM D790.
In some embodiments, the thermoplastic resin composition may have a tensile strength retention rate of about 80% or more, for example, about 80% to about 95%, as calculated according to Equation 1.
A molded article according to the present invention is formed of the thermoplastic resin composition set forth above. The thermoplastic resin composition may be prepared in pellet form. The prepared pellets may be produced into various molded articles (products) by various molding methods such as injection molding, extrusion, vacuum molding, casting, and the like. These molding methods are well known to those skilled in the art to which the present invention pertains. The molded article has good properties in terms of metal adhesion, impact resistance, rigidity, thermal stability, and balance therebetween, and thus is useful as interior/exterior materials for electronic devices, interior/exterior materials for automobiles, and the like.
A composite material according to the present invention may comprise: a plastic member as the molded article; and a metal member adjoining the plastic member.
In some embodiments, the metal member may directly adjoin the plastic member without a bonding agent interposed therebetween.
In some embodiments, the metal member may comprise at least one of aluminum, titanium, iron, and zinc.
In some embodiments, the metal member may comprise aluminum and the plastic member may have a metal adhesion strength of about 35 MPa to about 50 MPa, for example, about 36 MPa to about 48 MPa, as measured with respect to the metal member in accordance with ISO 19095. The plastic member may have a dart impact strength of about 76 cm to about 120 cm, for example, about 78 cm to about 110 cm, as determined by measuring a height from which dropping a 500 g dart results in cracking of a 2 mm thick specimen in accordance with the DuPont drop test method, a notched Izod impact strength of about 12.5 kgf cm/cm to about 20 kgf cm/cm, for example, about 12.7 kgf cm/cm to about 17 kgf cm/cm, as measured on a ⅛″ thick specimen in accordance with ASTM D256, a flexural modulus of about 80,000 kgf/cm2 to about 140,000 kgf/cm2, for example, about 80,000 kgf/cm2 to about 130,000 kgf/cm2, as measured on a ¼″ thick specimen at a rate of 2.8 mm/min in accordance with ASTM D790, and a tensile strength retention rate of about 80% or more, for example, about 80% to about 95%, as calculated according to Equation 1.
Next, the present invention will be described in more detail with reference to some examples. It should be understood that these examples are provided for illustration only and are not to be construed in any way as limiting the present invention.
Details of components used in Examples and Comparative Examples are as follows.
A polybutylene terephthalate resin (PBT, manufacturer: Shinkong Synthetic Fibers Corporation, product name: Shinite K006, intrinsic viscosity [η]: about 1.3 dL/g) was used.
A bisphenol A polycarbonate resin (PC, manufacturer: Lotte Chemical Corporation, weight average molecular weight: about 25,000 g/mol) was used.
Flat glass fibers (manufacturer: Nittobo Co., Ltd., product name: CSG 3PA-820, minor diameter: about 7 μm, cross-sectional aspect ratio: about 4, pre-processing length: about 3 mm) were used.
Glycidyl methacrylate-modified polyethylene (PE-GMA, manufacturer: Sumitomo Chemical Co., Ltd., product name: Igetabond) was used.
The aforementioned components were mixed in amounts as listed in Tables 1, 2, 3, and 4, followed by extrusion at 260° C., thereby preparing a thermoplastic resin composition in pellet form. Here, extrusion was performed using a twin-screw extruder (L/D: 44, ¢: 45 mm). The prepared pellets were dried at 80° C. for 4 hours or more and then subjected to injection molding using a 6 oz. injection machine (molding temperature: 270° C., mold temperature: 120° C.), thereby preparing specimens. The prepared specimens were evaluated as to the following properties. Results are shown in Tables 1, 2, 3, and 4.
Tensile strength retention rate (%)=TS1/TS0×100 [Equation 1]
From the results, it could be seen that the thermoplastic resin composition according to the present invention exhibited good properties in terms of metal adhesion (metal adhesion strength), impact resistance (dart impact strength and/or notched Izod impact strength), rigidity (flexural modulus), thermal stability (tensile strength retention rate), and balance therebetween.
Conversely, it could be seen that the thermoplastic resin composition of Comparative Example 1 prepared using an insufficient amount of the polycarbonate resin exhibited deterioration in metal adhesion, impact resistance, and the like; the thermoplastic resin composition of Comparative Example 2 prepared using an excess of the polycarbonate resin exhibited deterioration in metal adhesion and the like; the thermoplastic resin composition of Comparative Example 3 prepared using an insufficient amount of the flat glass fibers exhibited deterioration in impact resistance, rigidity, thermal stability and the like; and the thermoplastic resin composition of Comparative Example 4 prepared using an excess of the flat glass fibers exhibited deterioration in metal adhesion, impact resistance, and the like. In addition, it could be seen that the thermoplastic resin composition of Comparative Example 5 prepared using an insufficient amount of the epoxy-modified olefin polymer exhibited deterioration in impact resistance, thermal stability, and the like; the thermoplastic resin composition of Comparative Example 6 prepared using an excess of the epoxy-modified olefin polymer exhibited deterioration in metal adhesion and the like; the thermoplastic resin composition of Comparative Example 7 prepared using an insufficient amount of the maleic anhydride-modified polyolefin exhibited deterioration in impact resistance, thermal stability, and the like; the thermoplastic resin composition of Comparative Example 8 prepared using an excess of the maleic anhydride-modified polyolefin exhibited deterioration in metal adhesion, impact resistance, and the like; and the thermoplastic resin composition of Comparative Example 8 prepared using the maleic anhydride-modified ethylene-butene copolymer (E2) instead of the maleic anhydride-modified polyolefin according to the present invention exhibited deterioration in metal adhesion, impact resistance, thermal stability, and the like.
In addition, it could be seen that, even with the epoxy-modified olefin polymer (D) and the maleic anhydride-modified polyolefin (E) within the content ranges according to the present invention, the thermoplastic resin composition (Comparative Example 10) having a weight ratio (D:E) (1:0.017) less than 1:0.1 exhibited deterioration in impact resistance, thermal stability, and the like, and the thermoplastic resin composition (Comparative Example 11) having a weight ratio (D:E) (1:1.3) exceeding 1:1 exhibited deterioration in impact resistance, thermal stability, and the like.
Although some embodiments have been described herein, it will be understood by those skilled in the art that various modifications, changes, and alterations can be made without departing from the spirit and scope of the invention. Therefore, it should be understood that these embodiments are provided for illustration only and are not to be construed in any way as limiting the present invention. The scope of the present invention should be defined by the appended claims rather than by the foregoing description, and the claims and equivalents thereto are intended to cover such modifications and the like as would fall within the scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2021-0069846 | May 2021 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2022/006390 | 5/4/2022 | WO |
