Patent Application
20240317992
The present invention relates to a thermoplastic resin composition and a molded article formed therefrom. More particularly, the present invention relates to a thermoplastic resin composition that exhibits good properties in terms of metal adhesion, impact resistance, rigidity, and balance therebetween, and a molded article formed 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 comprising interior/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 comprising impact resistance and rigidity of the polyester resin by adding additives, such as inorganic fillers and the like, to the polyester resin. For example, polybutylene terephthalate (PBT) resins reinforced by inorganic fillers, such as glass fiber and the like, are used for automobile components or housings of mobile phones. However, such materials have a limitation in improvement in impact resistance, rigidity, and the like, and cause deterioration in metal adhesion and the like.
Therefore, there is a need for a thermoplastic resin composition having good properties in terms of metal adhesion, impact resistance, rigidity, and balance therebetween.
The background technique of the present invention is disclosed in Korean Patent Registration No. 10-0709878 and the like.
It is one aspect of the present invention to provide a thermoplastic resin composition that exhibits good properties in terms of metal adhesion, impact resistance, rigidity, and balance therebetween.
It is another aspect of the present invention to provide a molded article produced from the thermoplastic resin composition.
The above and other aspects of the present invention can be achieved by the present invention described below.
The present invention provides a thermoplastic resin composition that has good properties in terms of metal adhesion, impact resistance, rigidity, 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) a flat glass fiber; (D) an epoxy-modified olefin copolymer; and (E) a poly(ether ester) copolymer.
As used herein to represent a specific numerical range, the expression “a to b” means “≥a and ≤b”.
According to the present invention, the polyester resin may be selected from any polyester resins used in a typical thermoplastic resin composition. For example, the polyester resin may be obtained by polycondensation of a dicarboxylic acid component and a diol component, in which the dicarboxylic acid component may comprise: 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-naphthalene dicarboxylic acid, and the like; and 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 in which the diol component may comprise 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, and a cycloalkylene diol.
In some embodiments, the polyester resin may comprise at least one of polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), and polycyclohexylenedimethylene terephthalate (PCT). Preferably, the polyester resin comprises at least one of polybutylene terephthalate, polyethylene terephthalate, and polycyclohexylenedimethylene terephthalate.
In some embodiments, the polyester resin may have an inherent viscosity [η] of about 0.5 dl/g to about 1.5 dl/g, for example, about 0.7 dl/g to about 1.4 dl/g, as measured in accordance with ASTM D2857. Within this range, the thermoplastic resin composition can exhibit good mechanical properties and the like.
According to the present invention, the polycarbonate resin serves to improve impact resistance and appearance characteristics of the thermoplastic resin composition and may comprise any 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, or carbonate diester.
In some embodiments, the diphenols may comprise, 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 polycarbonate resin prepared by adding a tri- or higher polyfunctional compound, specifically, a tri- or higher valent phenol group-containing compound, in an amount of about 0.05 mol % to about 2 mol % 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. In addition, the polycarbonate resin may be partly 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 500,000 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 fluidity (processability).
In some embodiments, the polycarbonate resin may be present in an amount of about 5 to about 25 parts by weight, for example, about 10 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 5 parts by weight relative to about 100 parts by weight of the polyester resin, the resin composition can suffer from deterioration in impact resistance, metal adhesion, and the like, and if the content of the polycarbonate resin exceeds about 25 parts by weight, the resin composition can suffer from deterioration in metal adhesion, rigidity, and the like.
According to the present invention, the flat glass fiber serves to improve rigidity, impact resistance, and metal adhesion of the thermoplastic resin composition comprising the polyester resin and the polycarbonate resin together with the epoxy-modified olefin copolymer and the poly(ether ester) copolymer.
In some embodiments, the flat glass fiber may have a rectangular cross-section, a rectangular cross-section with a curved corner, or an elliptical cross-section, and may have a cross-section aspect ratio (long-side length/short-side length in cross-section) of about 1.5 to about 10, a short-side length of about 2 μm to about 10 μm, and a pre-processing length of about 2 mm to about 20 mm. Within this range, the thermoplastic resin composition can have good properties in terms of rigidity, processability, flexibility, and the like.
In some embodiments, the flat glass fiber may be subjected to surface treatment with a typical surface treatment agent. The surface treatment agent may comprise a silane compound, a urethane compound, and an epoxy compound, without being limited thereto.
In some embodiments, the flat glass fiber may be present in an amount of about 50 to about 150 parts by weight, for example, about 60 to about 140 parts by weight, relative to about 100 parts by weight of the polyester resin. If the content of the flat glass fiber is less than about 50 parts by weight relative to about 100 parts by weight of the polyester resin, the resin composition can suffer from deterioration in metal adhesion, impact resistance, rigidity, and the like, and if the content of the flat glass fiber exceeds about 150 parts by weight, the resin composition can suffer from deterioration in metal adhesion, impact resistance, fluidity, appearance characteristics, and the like.
According to the present invention, the epoxy-modified olefin copolymer serves to improve impact resistance, rigidity, and metal adhesion of the thermoplastic resin composition comprising the polyester resin and the polycarbonate resin together with the flat glass fiber and the poly(ether ester) copolymer, and may be a reactive olefin copolymer prepared by adding an epoxy compound as a reactive functional group to an olefin copolymer for modification of the olefin copolymer.
In some embodiments, the epoxy compound may comprise glycidyl (meth)acrylate, allyl glycidyl ether, 2-methyl-allyl glycidyl ether, and mixtures thereof.
In some embodiments, the epoxy-modified olefin copolymer may be prepared through copolymerization of the epoxy compound with an olefin copolymer obtained through copolymerization of an alkylene monomer and an alkyl (meth)acrylate monomer. The alkylene monomer may be a C2 to C10 alkylene, for example, ethylene, propylene, isopropylene, butylene, isobutylene, octene, and combinations thereof. The alkyl (meth)acrylate monomer may be a C1 to C8 alkyl (meth)acrylate, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, and combinations thereof.
In some embodiments, the epoxy-modified olefin copolymer may comprise a glycidyl (meth)acrylate-modified ethylene-methyl acrylate copolymer, a glycidyl (meth)acrylate-modified ethylene-ethyl acrylate copolymer, a glycidyl (meth)acrylate-modified ethylene-butyl acrylate copolymer, and combinations thereof.
In some embodiments, the epoxy-modified olefin copolymer 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, as measured at 190° C. under a load of 2.16 kg in accordance with ASTM D1238. Within this range, the thermoplastic resin composition can exhibit good impact resistance.
In some embodiments, the epoxy-modified olefin copolymer may be present in an amount of about 1.5 to about 15 parts by weight, for example, about 2 to about 13 parts by weight, relative to about 100 parts by weight of the polyester resin. If the content of the epoxy-modified olefin copolymer is less than about 1.5 parts by weight relative to about 100 parts by weight of the polyester resin, the thermoplastic resin composition can suffer from deterioration in impact resistance and the like, and if the content of the epoxy-modified olefin copolymer exceeds about 15 parts by weight, the thermoplastic resin composition can suffer from deterioration in metal adhesion, rigidity, and the like.
In some embodiments, the flat glass fiber (C) and the epoxy-modified olefin copolymer (D) may be present in a weight ratio (C:D) of about 1:0.014 to about 1:0.22, for example, about 1:0.02 to about 1:0.15. Within this range, the thermoplastic resin composition can exhibit further improved properties in terms of impact resistance, metal adhesion, rigidity, and the like.
According to the present invention, the poly(ether ester) copolymer serves to improve metal adhesion, impact resistance, and rigidity of the thermoplastic resin composition comprising the polyester resin and the polycarbonate resin together with the flat glass fiber and the epoxy-modified olefin copolymer, and may be a polymer of a reaction mixture comprising a C4 to C20 dicarboxylic acid; a C1 to C10 diol; and a poly(oxyalkylene) diol.
In some embodiments, the poly(ether ester) copolymer may comprise poly(1,4-butylene terephthalate-co-tetramethylene oxalate) copolymer (PBT-co-PTMO).
In some embodiments, the poly(ether ester) copolymer may have a melt volume-flow rate (MVR) of about 1 cm3/10 min to about 150 cm3/10 min, for example, about 2 cm3/10 min to about 100 cm3/10 min, as measured at 230° C. under a load of 2.16 kg in accordance with ISO 1133. Within this range, the thermoplastic resin composition can exhibit good impact resistance, metal adhesion, and the like.
In some embodiments, the poly(ether ester) copolymer may be present in an amount of about 0.5 to about 10 parts by weight, for example, about 0.8 to about 7.5 parts by weight, relative to about 100 parts by weight of the polyester resin. If the content of the poly(ether ester) copolymer is less than about 0.5 parts by weight relative to about 100 parts by weight of the polyester resin, the resin composition can suffer from deterioration in impact resistance and the like, and if the content of the poly(ether ester) copolymer exceeds about 10 parts by weight, the resin composition can suffer from deterioration in metal adhesion, rigidity, and the like.
In some embodiments, the epoxy-modified olefin copolymer (D) and the poly(ether ester) (E) may be present in a weight ratio (D:E) of about 1:0.06 to about 1:3.75, for example, about 1:0.1 to about 1:1.5. If the weight ratio (D:E) is less than about 1:0.06, the resin composition can suffer from deterioration in impact resistance and the like, and if the weight ratio (D:E) exceeds about 1:3.75, the resin composition can suffer from deterioration in metal adhesion and the like.
In some embodiments, the thermoplastic resin composition may further comprise additives used for typical thermoplastic resin compositions. Examples of the additives may comprise an impact modifier, a flame retardant, an antioxidant, an anti-dripping agent, a lubricant, a release agent, a nucleating agent, an antistatic agent, a stabilizer, pigments, dyes, and mixtures thereof, without being limited thereto. The additives may be present in an amount of about 0.001 to about 40 parts by weight, for example, about 0.1 to about 10 parts by weight, relative to about 100 parts by weight of the polyester resin.
In some embodiments, the thermoplastic resin composition may be prepared in pellet form by mixing the aforementioned components, followed by melt extrusion at about 200° C. to about 280° C., for example, at about 220° C. to about 270° C., using a typical twin-screw extruder.
In some embodiments, the thermoplastic resin composition may have a metal bonding strength of about 36 MPa to about 50 MPa, for example, about 37 MPa to about 48 MPa, as measured with respect to an aluminum specimen in accordance with ISO 19095.
In some embodiments, the thermoplastic resin composition may have a dart drop height of about 75 cm to about 120 cm, for example, about 76 cm to about 118 cm, at which cracks are generated on a 2 mm thick specimen upon dropping a 500 g dart onto the specimen in accordance with a DuPont drop test method.
In some embodiments, the thermoplastic resin composition may have a notched Izod impact strength of about 10 kgf·cm/cm to about 30 kgf·cm/cm, for example, about 11 kgf·cm/cm to about 25 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 tensile strength of about 117,000 kgf/cm2 to about 140,000 kgf/cm2, for example, about 118,000 kgf/cm2 to about 138,000 kgf/cm2, as measured on a 3.2 mm thick specimen at 50 mm/min in accordance with ASTM D638.
A molded article according to the present invention is produced from the thermoplastic resin composition as set forth above. The thermoplastic resin composition may be prepared in pellet form. The prepared pellets may be produced into various molded products (articles) by various molding methods, such as injection molding, extrusion molding, vacuum molding, casting, and the like. These molding methods are well known to those skilled in the art. The molded articles have good properties in terms of metal adhesion, impact resistance, rigidity, and balance therebetween, and thus can be advantageously used for interior/exterior materials of electrical/electronic products, interior/exterior materials of automobiles, and the like.
A composition material according to the present invention may comprise a plastic member produced from the molded article; and a metal member adjoining the plastic member.
In some embodiments, the plastic member may directly adjoin the metal member without a bonding agent interposed therebetween. For example, the plastic member may be formed to directly adjoin the metal member by molding the plastic member on the metal member, which is subjected to surface treatment by an electrochemical method, through injection molding or the like.
In some embodiments, the metal member may comprise at least one of aluminum, titanium, iron, and zinc.
In some embodiments, the metal member comprises aluminum, and the plastic member may have a metal bonding strength of about 36 MPa to about 50 MPa, for example, about 37 MPa to about 48 MPa, as measured with respect to the metal member in accordance with ISO 19095; a dart drop height of about 75 cm to about 120 cm, for example, about 76 cm to about 118 cm, at which cracks are generated on a 2 mm thick plastic member upon dropping a 500 g dart onto the specimen in accordance with a DuPont drop test method; a notched Izod impact strength of about 10 kgf·cm/cm to about 30 kgf·cm/cm, for example, about 11 kgf·cm/cm to about 25 kgf·cm/cm, as measured on a ⅛″ thick specimen in accordance with ASTM D256; and a tensile strength of about 117,000 kgf/cm2 to about 140,000 kgf/cm2, for example, about 118,000 kgf/cm2 to about 138,000 kgf/cm2, as measured on a 3.2 mm thick specimen at 50 mm/min in accordance with ASTM D638.
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 invention.
Details of components used in Examples and Comparative Examples are as follows.
A polybutylene terephthalate (PBT) resin having an inherent viscosity [η] of about 1.3 dl/g (Manufacturer: Shinkong Co., Ltd., Product: Shinite K006) was used.
A bisphenol-A polycarbonate resin having a weight average molecular weight of about 25,000 g/mol (Manufacturer: Lotte Chemical Co., Ltd.) was used.
Flat glass fibers having a short-side length of about 7 μm, a cross-section aspect ratio of about 4, and a pre-processing length of about 3 mm (Manufacturer: Nittobo Co., Ltd., Product: CSG 3PA-820) were used.
A poly(1,4-butylene terephthalate-co-tetramethylene oxalate) copolymer having a melt volume-flow rate (MVR) of about 5 cm3/10 min (PBT-co-PTMO, Manufacturer: DuPont, Product: Hytrel 4056) was used.
The above components were mixed in amounts as listed in Tables 1 to 4 and subjected to extrusion under conditions of 260° C., thereby preparing a thermoplastic resin composition in pellet form. Extrusion was performed using a twin-screw extruder (L/D=44, Φ: 45 mm) and the prepared pellets were dried at 100° C. for 4 hours or more and injection-molded in a 6 oz. injection molding machine (molding temperature: 270° C., mold temperature: 120° C.), thereby preparing specimens. The prepared specimens were evaluated as to the following properties by the following method, and results are shown in Tables 1 to 4.
From the result, it could be seen that the thermoplastic resin compositions according to the present invention had good properties in terms of metal adhesion (metal bonding strength), impact resistance (sheet impact strength and/or notched Izod impact strength), rigidity (tensile strength), and balance therebetween.
Conversely, it could be seen that the resin composition of Comparative Example 1 comprising an insufficient amount of the polycarbonate resin suffered from deterioration in impact resistance and the like; the resin composition of Comparative Example 2 comprising an excess of the polycarbonate resin suffered from deterioration in metal adhesion and the like; the resin composition of Comparative Example 3 comprising an insufficient amount of the flat glass fiber suffered from deterioration in metal adhesion, impact resistance, rigidity, and the like; and the resin composition of Comparative Example 4 comprising an excess of the flat glass fiber suffered from deterioration in metal adhesion, impact resistance and the like. It could be seen that the resin composition of Comparative Example 5 comprising an insufficient amount of the epoxy-modified olefin copolymer suffered from deterioration in impact resistance, and the like; the resin composition of Comparative Example 6 comprising an excess of the epoxy-modified olefin copolymer suffered from deterioration in metal adhesion, rigidity, and the like; the resin composition of Comparative Example 7 comprising the maleic anhydride-modified ethylene-butene copolymer (D2) instead of the epoxy-modified olefin copolymer according to the present invention suffered from deterioration in impact resistance and the like; and the resin composition of Comparative Example 8 comprising the ethylene-methyl acrylate copolymer (D3) instead of the epoxy-modified olefin copolymer suffered from deterioration in metal adhesion, and the like. It could be seen that the resin composition of Comparative Example 9 comprising an insufficient amount of the poly(ether ester) copolymer suffered from deterioration in impact resistance and the like; the resin composition of Comparative Example 10 comprising an excess of the poly(ether ester) copolymer suffered from deterioration in metal adhesion, rigidity, and the like; and the resin composition of Comparative Example 11 comprising the poly(1,4-butylene terephthalate-co-hexamethylene carbonate) copolymer (F) instead of the poly(ether ester) copolymer according to the present invention suffered from deterioration in metal adhesion and the like.
Further, it could be seen that, even with the epoxy-modified olefin copolymer and the poly(ether ester) copolymer, the thermoplastic resin composition having a weight ratio (D:E) of less than about 1:0.06 (a weight ratio of 1:0.05) (Comparative Example 12) suffered from deterioration in impact resistance and the like; and the thermoplastic resin composition having a weight ratio (D:E) of greater than about 1:3.75 (a weight ratio of 1:5) (Comparative Example 13) suffered from deterioration in metal adhesion and the like.
Although the present invention has been described with reference to some example embodiments, it should be understood by those skilled in the art that these embodiments are given by way of illustration only, and that various modifications, variations and alterations can be made without departing from the spirit and scope of the invention. Therefore, the embodiments should not be construed as limiting the technical spirit of the present invention, but should be construed as illustrating the technical spirit of the present invention. The scope of the invention should be interpreted according to the following appended claims as covering all modifications or variations derived from the appended claims and equivalents thereto.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2020-0186418 | Dec 2020 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2021/017107 | 11/19/2021 | WO |
