Thermoplastic resin composition and molded article prepared therefrom

Abstract

The thermoplastic resin composition of the present invention comprises: about 100 parts by weight of a polypropylene resin; about 30 parts by weight to about 45 parts by weight of glass fibers surface-treated with polyolefin; about 50 parts by weight to about 60 parts by weight of a phosphorus-nitrogen based flame retardant including about 70% by weight to about 90% by weight of piperazine pyrophosphate and about 10% by weight to about 30% by weight of a melamine polyphosphate; and about 1.5 parts by weight to about 4.5 parts by weight of a maleic anhydride modified polypropylene. The thermoplastic resin composition has excellent flame retardancy (film flame retardancy and electrical flame retardancy), impact resistance, rigidity, extrudability, balance of physical properties, and the like.

Description

Technical Field

[0001] The present invention relates to a thermoplastic resin composition and a molded article manufactured therefrom. More specifically, the present invention relates to a thermoplastic resin composition having good properties in terms of flame retardancy (film flame retardancy and resistance to ignition), impact resistance, rigidity, extrudability, and balance of properties therebetween, and a molded article manufactured therefrom. Background Art

[0002] Due to its good chemical resistance, weather resistance, and processability, polypropylene resin can be easily manufactured into injection molded products, films, and blow molded products, and is widely used in various applications such as electronic components, automobiles, and building materials.

[0003] Polypropylene resin is inherently flammable due to its chemical structure, and various organic or inorganic flame retardants need to be added to impart flame retardancy thereto. However, due to growing environmental concerns and stricter regulations on existing halogen-based flame retardants, there is an increasing need to reduce or eliminate the use of halogen-based flame retardants in thermoplastic resin compositions to ensure the applicability of thermoplastic resin compositions as environmentally friendly materials.

[0004] However, compared with the use of halogen-based flame retardants, the use of non-halogen-based flame retardants alone in thermoplastic resin compositions can result in a significant reduction in flame retardancy. In addition, combining non-halogen-based flame retardants with inorganic fillers to improve the flame retardancy and mechanical properties of olefin-based thermoplastic resin compositions can lead to deterioration of extrudability and plasticity.

[0005] Therefore, there is a need for a thermoplastic resin composition having good properties in terms of flame retardancy (film flame retardancy and resistance to ignition), impact resistance, rigidity, extrudability, and balance of properties therebetween.

[0006] The background art of the present invention is disclosed in Korean Patent Registration No. 10-1863421, etc. Summary of the Invention

[0007]

Technical Problem

[0008] An object of the present invention is to provide a thermoplastic resin composition having good properties in terms of flame retardancy (film flame retardancy and resistance to ignition), impact resistance, rigidity, extrudability, and balance of properties therebetween.

[0009] Another object of the present invention is to provide a molded article manufactured from the above thermoplastic resin composition.

[0010] From the following detailed description of the embodiments, the above and other objects of the present invention will become apparent.

[0011]

Technical Solution

[0012] 1. One aspect of the present invention relates to a thermoplastic resin composition. The thermoplastic resin composition comprises: about 100 parts by weight of a polypropylene resin; about 30 to about 45 parts by weight of glass fibers surface-treated with a polyolefin; about 50 to about 60 parts by weight of a phosphorus-nitrogen flame retardant, which comprises about 70 wt% to about 90 wt% of piperazine pyrophosphate and about 10 wt% to about 30 wt% of melamine polyphosphate; and about 1.5 to about 4.5 parts by weight of maleic anhydride-modified polypropylene.

[0013] 2. In Embodiment 1, the polypropylene resin may comprise at least one of a homopolypropylene resin, a block polypropylene resin, and a random polypropylene resin.

[0014] 3. In Embodiment 1 or Embodiment 2, the glass fibers surface-treated with a polyolefin may have a polyolefin content of about 0.3 wt% to about 1.7 wt%.

[0015] 4. In Embodiments 1 to 3, the polyolefin of the glass fibers surface-treated with a polyolefin may comprise at least one of polypropylene and polyethylene.

[0016] 5. In Embodiments 1 to 4, the maleic anhydride-modified polypropylene may have a graft degree of maleic anhydride in the range of about 0.5 wt% to about 3.0 wt%.

[0017] 6. In Embodiments 1 to 5, the maleic anhydride-modified polypropylene may have a melt flow index of about 80 g / 10 min to about 140 g / 10 min measured at a temperature of 230 °C under a load of 2.16 kg according to ASTM D1238.

[0018] 7. In Embodiments 1 to 6, the weight ratio of the glass fibers surface-treated with a polyolefin to the phosphorus-nitrogen flame retardant may be in the range of about 1:1.2 to 1:2.

[0019] 8. In Embodiments 1 to 7, the weight ratio of the maleic anhydride-modified polypropylene to the glass fibers surface-treated with a polyolefin may be in the range of about 1:10 to about 1:20.

[0020] 9. In Embodiments 1 to 8, the weight ratio of the maleic anhydride-modified polypropylene to the phosphorus-nitrogen flame retardant may be in the range of about 1:15 to about 1:30.

[0021] 10. In Embodiments 1 to 9, the thermoplastic resin composition may have a flame retardancy of V-0 or higher measured on an injection-molded sample with a thickness of 0.8 mm by the UL-94 vertical test method.

[0022] 11. In Embodiments 1 to 10, the thermoplastic resin composition may have a glow wire ignition temperature (GWIT) of about 750 °C or higher as measured in accordance with UL746A on a sample having dimensions of 100 mm × 100 mm × 1.5 mm.

[0023] 12. In Embodiments 1 to 11, the thermoplastic resin composition may have a notched Izod impact strength of about 4 kgf·cm / cm to about 8 kgf·cm / cm as measured in accordance with ASTM D256 on a 1 / 8" thick sample.

[0024] 13. In Embodiments 1 to 12, the thermoplastic resin composition may have a flexural modulus of about 48,000 kgf / cm 2 to about 60,000 kgf / cm 2 as measured in accordance with ASTM D790 at a crosshead speed of 2.8 mm / min on a 1 / 4" thick sample.

[0025] 14. Another aspect of the present invention relates to a molded article. The molded article is made from the thermoplastic resin composition according to any one of Embodiments 1 to 13.

[0026]

Advantageous Effects

[0027] The present invention provides a thermoplastic resin composition having good properties in terms of flame retardancy (film flame retardancy and resistance to ignition), impact resistance, rigidity, extrudability, and the balance of properties therebetween. Detailed Embodiments

[0028] Hereinafter, embodiments of the present invention will be described in detail.

[0029] The thermoplastic resin composition according to the present invention includes (A) a polypropylene resin; (B) glass fibers surface-treated with a polyolefin; (C) a phosphorus-nitrogen flame retardant; and (D) maleic anhydride-modified polypropylene.

[0030] When used herein to denote a specific numerical range, "a to b" means "a ≤ and ≤ b".

[0031] (A) Polypropylene Resin

[0032] The polypropylene resin according to an embodiment of the present invention, when used together with glass fibers surface-treated with a polyolefin, a specific phosphorus-nitrogen flame retardant, and maleic anhydride-modified polypropylene, is used to improve the flame retardancy (film flame retardancy and resistance to ignition), impact resistance, rigidity, extrudability, and the balance of properties therebetween of the thermoplastic resin composition, and may include the polypropylene resin used in a typical thermoplastic resin composition.

[0033] In some embodiments, the polypropylene resin may include at least one of a homopolypropylene resin, a block polypropylene resin, and a random polypropylene resin. Herein, the block polypropylene resin may include a block polypropylene resin containing a homopolypropylene block and an ethylene-propylene copolymer block and / or a homopolyethylene block, and the random polypropylene resin may include an ethylene-propylene random copolymer.

[0034] In some embodiments, the polypropylene resin may include a mixture of about 10 wt% to about 90 wt% of a homopolypropylene resin and about 10 wt% to about 90 wt% of a block polypropylene resin.

[0035] In some embodiments, the polypropylene resin may have a melt flow index (MI) of about 1 g / 10 min to about 100 g / 10 min, such as about 5 g / 10 min to about 80 g / 10 min, 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 may be excellent in terms of mechanical properties, moldability, extrudability, etc.

[0036] (B) Glass fibers treated with a polyolefin

[0037] According to an embodiment of the present invention, glass fibers, when applied to a polypropylene resin together with a specific phosphorus-nitrogen flame retardant and maleic anhydride-modified polypropylene, are used to improve the flame retardancy (film flame retardancy and resistance to ignition), impact resistance, rigidity, extrudability, balance of properties therebetween, etc. of the thermoplastic resin composition, and may include glass fibers treated with a polyolefin as a sizing agent.

[0038] In some embodiments, based on the total weight of the glass fibers treated with a polyolefin, the polyolefin (sizing agent) may be present in an amount of about 0.3 wt% to about 1.7 wt%, such as about 0.5 wt% to about 1.5 wt%. Within this range, the thermoplastic resin composition may have good properties in terms of impact resistance, rigidity, appearance, etc.

[0039] In some embodiments, the polyolefin (sizing agent) may include at least one of polypropylene and polyethylene.

[0040] In some embodiments, the glass fibers may be provided in fiber form and may have various cross-sectional shapes, such as a circular shape, an oval shape, a rectangular shape, etc. For example, using fibrous glass fibers having a circular cross-section and / or a rectangular cross-section as the glass fibers may be advantageous in terms of mechanical properties.

[0041] In some embodiments, glass fibers having a circular cross-section may have a cross-sectional diameter of about 5 μm to about 20 μm and a pre-processed length of about 2 mm to about 20 mm measured using a scanning electron microscope (SEM), and glass fibers having a rectangular cross-section may have an aspect ratio (major cross-sectional diameter / minor cross-sectional diameter) of about 1.5 to about 10, a minor diameter of about 2 μm to about 10 μm, and a pre-processed length of about 2 mm to about 20 mm measured using a scanning electron microscope (SEM). Within these ranges, the thermoplastic resin composition can be excellent in mechanical properties, appearance, etc.

[0042] In some embodiments, relative to about 100 parts by weight of the polypropylene resin, glass fibers treated with a polyolefin surface treatment may be present in an amount of about 30 parts by weight to about 45 parts by weight, such as about 35 parts by weight to about 41 parts by weight. If the content of the glass fibers treated with a polyolefin surface treatment is less than about 30 parts by weight relative to about 100 parts by weight of the polypropylene resin, the thermoplastic resin composition may have poor properties in terms of impact resistance, rigidity, etc., and if the content of the glass fibers treated with a polyolefin surface treatment exceeds about 45 parts by weight relative to about 100 parts by weight of the polypropylene resin, the thermoplastic resin composition may have poor properties in terms of flame retardancy (film flame retardancy and resistance to ignition), appearance, etc.

[0043] (C) Phosphorus-nitrogen flame retardant

[0044] The phosphorus-nitrogen flame retardant according to one embodiment of the present invention, when applied to a polypropylene resin together with glass fibers treated with a polyolefin surface treatment and maleic anhydride-modified polypropylene, is used to improve the flame retardancy (film flame retardancy and resistance to ignition), impact resistance, rigidity, extrudability, balance of properties therebetween, etc. of the thermoplastic resin composition, and may include a phosphorus-nitrogen flame retardant containing piperazine pyrophosphate and melamine polyphosphate.

[0045] In some embodiments, the phosphorus-nitrogen flame retardant may include about 70 wt% to about 90 wt%, such as about 75 wt% to about 85 wt% of piperazine pyrophosphate and about 10 wt% to about 30 wt%, such as about 15 wt% to about 25 wt% of melamine polyphosphate. If the content of piperazine pyrophosphate is less than about 70 wt% (if the content of melamine polyphosphate exceeds 30 wt%), the thermoplastic resin composition may have poor properties in terms of flame retardancy (film flame retardancy and resistance to ignition), impact resistance, etc., and if the content of piperazine pyrophosphate exceeds about 90 wt% (if the content of melamine polyphosphate is less than 10 wt%), the thermoplastic resin composition may have poor properties in terms of impact resistance, rigidity, extrudability, appearance, etc.

[0046] In some embodiments, the phosphorus-nitrogen flame retardant may further include zinc oxide. With respect to about 100 parts by weight of the phosphorus-nitrogen flame retardant, zinc oxide may optionally be present in an amount of about 0.5 parts by weight to about 3 parts by weight, such as about 0.7 parts by weight to about 2.5 parts by weight. Within this range, the thermoplastic resin composition may have further improved properties in terms of flame retardancy, extrudability, appearance, etc.

[0047] In some embodiments, with respect to about 100 parts by weight of the polypropylene resin, the phosphorus-nitrogen flame retardant may be present in an amount of about 50 parts by weight to about 60 parts by weight, such as about 53 parts by weight to about 59 parts by weight. If the content of the phosphorus-nitrogen flame retardant is less than about 50 parts by weight with respect to about 100 parts by weight of the polypropylene resin, the thermoplastic resin composition may have poor properties in terms of flame retardancy (film flame retardancy and resistance to ignition) and rigidity, etc., while if the content of the phosphorus-nitrogen flame retardant exceeds about 60 parts by weight with respect to about 100 parts by weight of the polypropylene resin, the thermoplastic resin composition may have poor properties in terms of impact resistance, extrudability, appearance, etc.

[0048] In some embodiments, glass fibers surface-treated with a polyolefin and the phosphorus-nitrogen flame retardant may be present in a weight ratio of about 1:1.2 to about 1:2, such as about 1:1.3 to about 1:1.8 (glass fibers surface-treated with a polyolefin:phosphorus-nitrogen flame retardant). Within this range, the thermoplastic resin composition (and molded articles made therefrom) may be further improved in terms of mechanical properties, flame retardancy, etc.

[0049] (D) Maleic anhydride-modified polypropylene

[0050] The maleic anhydride-modified polypropylene according to one embodiment of the present invention, when applied to a polypropylene resin together with glass fibers surface-treated with a polyolefin and the phosphorus-nitrogen flame retardant, is used to improve the flame retardancy (film flame retardancy and resistance to ignition), impact resistance, rigidity, extrudability, and the balance of properties therebetween of the thermoplastic resin composition, and may include maleic anhydride-modified polypropylene obtained by polymerizing (grafting) maleic anhydride onto polypropylene.

[0051] In some embodiments, the maleic anhydride-modified polypropylene may have a graft degree of maleic anhydride in the range of about 0.5 wt% to about 3 wt%, such as about 0.7 wt% to about 2.8 wt%. Within this range, the thermoplastic resin composition may have good properties in terms of impact resistance, flame retardancy, injection moldability, etc.

[0052] In some embodiments, the maleic anhydride-modified polypropylene may have a melt flow index of about 80 g / 10 min to about 140 g / 10 min, such as about 100 g / 10 min to about 120 g / 10 min, 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 may have good properties in terms of flame retardancy and the like.

[0053] In some embodiments, relative to about 100 parts by weight of the polypropylene resin, the maleic anhydride-modified polypropylene may be present in an amount of about 1.5 parts by weight to about 4.5 parts by weight, such as about 2 parts by weight to about 3.6 parts by weight. If the content of the maleic anhydride-modified polypropylene is less than about 1.5 parts by weight relative to about 100 parts by weight of the polypropylene resin, the thermoplastic resin composition may have poor properties in terms of flame retardancy, impact resistance, rigidity, etc., while if the content of the maleic anhydride-modified polypropylene exceeds about 4.5 parts by weight relative to about 100 parts by weight of the polypropylene resin, the thermoplastic resin composition may have poor properties in terms of flame retardancy, injection moldability, etc.

[0054] In some embodiments, the maleic anhydride-modified polypropylene and the glass fiber treated with a polyolefin surface treatment may be present in a weight ratio of about 1:10 to about 1:20, such as about 1:12 to about 1:20 (maleic anhydride-modified polypropylene: glass fiber treated with a polyolefin surface treatment). Within this range, the thermoplastic resin composition (and molded articles made therefrom) may have further improved properties in terms of impact resistance, flame retardancy, injection moldability, etc.

[0055] In some embodiments, the maleic anhydride-modified polypropylene and the phosphorus-nitrogen flame retardant may be present in a weight ratio of about 1:15 to about 1:30, such as about 1:17 to about 1:29 (maleic anhydride-modified polypropylene: phosphorus-nitrogen flame retardant). Within this range, the thermoplastic resin composition (and molded articles made therefrom) may have further improved properties in terms of impact resistance, flame retardancy, injection moldability, etc.

[0056] The thermoplastic resin composition according to one embodiment of the present invention may further include additives used in typical polypropylene resin compositions. The additives may include, for example, a drip inhibitor, an antioxidant, a surfactant, a lubricant, a mold release agent, a nucleating agent, a stabilizer, a pigment, a dye, and mixtures thereof, but are not limited thereto.

[0057] In some embodiments, relative to about 100 parts by weight of the polypropylene resin, the additives may optionally be present in an amount of about 0.001 parts by weight to about 40 parts by weight, such as about 0.1 parts by weight to about 10 parts by weight.

[0058] The thermoplastic resin composition according to an embodiment of the present invention can be prepared in pellet form by mixing the aforementioned components and then melt-extruding in a typical twin-screw extruder at a temperature of about 180°C to about 280°C, such as about 200°C to about 260°C.

[0059] In some embodiments, the thermoplastic resin composition may have a flame retardancy of V-0 or higher as measured by the UL-94 vertical test method on an injection-molded sample with a thickness of 0.8 mm.

[0060] In some embodiments, the thermoplastic resin composition may have a glow wire ignition temperature (GWIT) of about 750°C or higher, such as about 750°C to about 790°C, as measured in accordance with UL746A on a sample having dimensions of 100 mm × 100 mm × 1.5 mm.

[0061] In some embodiments, the thermoplastic resin composition may have a notched Izod impact strength of about 4 kgf·cm / cm to about 8 kgf·cm / cm, such as about 4.5 kgf·cm / cm to about 7 kgf·cm / cm, as measured in accordance with ASTM D256 on a 1 / 8" thick sample.

[0062] In some embodiments, the thermoplastic resin composition may have a flexural modulus of about 48,000 kgf / cm 2 to about 60,000 kgf / cm 2 such as about 49,000 kgf / cm 2 to about 58,000 kgf / cm 2 as measured in accordance with ASTM D790 at a crosshead speed of 2.8 mm / min on a 1 / 4" thick sample.

[0063] The molded product according to the present invention is formed from the above thermoplastic resin composition. The thermoplastic resin composition can be prepared in pellet form. The prepared pellets can be made into various molded articles (products) by various molding methods (such as injection molding, extrusion molding, vacuum molding, casting, etc.). These molding methods are well-known to those of ordinary skill in the art to which the present invention pertains.

[0064] The molded article according to the present invention has good properties in terms of flame retardancy (film flame retardancy and resistance to ignition), impact resistance, rigidity, extrudability, and the balance of properties therebetween. Therefore, the molded article is useful for products that require flame retardancy (such as the housings of household appliances, power boxes, etc.).

[0065]

Mode of Invention

[0066] Next, the present invention will be described in more detail with reference to some embodiments. However, it should be noted that these embodiments are provided for illustration only and should not be construed as limiting the present invention in any way.

[0067] Embodiment

[0068] Details of the components used in the examples and comparative examples are as follows:

[0069] (A) Polypropylene resin

[0070] A mixture of 72 wt% of a homopolypropylene resin (product name: HA5034, manufacturer: PolyMirae) and 28 wt% of a block polypropylene resin (product name: JSS350N, manufacturer: Lotte Chemical) was used.

[0071] (B) Glass fiber

[0072] (B1) Glass fiber treated with polypropylene surface treatment (product name: ECS11-03-508C, manufacturer: JUSHI) was used.

[0073] (B2) Glass fiber without surface treatment (product name: T249, manufacturer: NEG) was used.

[0074] (C) Phosphorus-nitrogen flame retardant

[0075] (C1) A mixture comprising 80 wt% of piperazine pyrophosphate (Cas No.: 66034-17-1, manufacturer: HainanZhongxin Chemical) and 20 wt% of melamine polyphosphate (product name: Melapur 200, manufacturer: BASF) was used.

[0076] (C2) A mixture comprising 75 wt% of piperazine pyrophosphate and 25 wt% of melamine polyphosphate was used.

[0077] (C3) A mixture comprising 85 wt% of piperazine pyrophosphate and 15 wt% of melamine polyphosphate was used.

[0078] (C4) A mixture comprising 65 wt% of piperazine pyrophosphate and 35 wt% of melamine polyphosphate was used.

[0079] (C5) A mixture comprising 95 wt% of piperazine pyrophosphate and 5 wt% of melamine polyphosphate was used.

[0080] (D) Maleic anhydride-modified polyolefin

[0081] (D1) Polypropylene modified with maleic anhydride (Product name: CHEMS MP600PP, Manufacturer: Chemko S.C.).

[0082] (D2) Polystyrene modified with maleic anhydride (Product name: SMA-725, Manufacturer: Jiaxing Huawen Chemical).

[0083] Examples 1 to 9 and Comparative Examples 1 to 10

[0084] Mix the foregoing components in the amounts listed in Tables 1, 2, 3, and 4, and then extrude at 200 °C to prepare a thermoplastic resin composition in the form of pellets. Here, extrusion is carried out using a twin-screw extruder (L / D: 36, diameter: 45 mm). Dry the prepared pellets at 80 °C for 2 hours or longer, and then injection mold using a 6-ounce injection molding machine (molding temperature: 210 °C, mold temperature: 60 °C) to prepare samples. Evaluate the following properties of the prepared samples. The results are shown in Tables 1, 2, 3, and 4.

[0085] Characteristic evaluation

[0086] (1) Film flame retardancy: Measure the flame retardancy on an injection molded sample with a thickness of 0.8 mm by the UL-94 vertical test method.

[0087] (B.O: Burnout)

[0088] (2) Resistance to ignition: Measure the glow wire ignition temperature (GWIT) (unit: °C) on a sample with dimensions of 100 mm × 100 mm × 1.5 mm in accordance with UL746A.

[0089] (3) Notched Izod impact strength (unit: kgf·cm / cm): Measure the notched Izod impact strength on a 1 / 8" thick sample in accordance with ASTM D256.

[0090] (4) Flexural modulus (unit: kgf / cm 2 ) : Measure the flexural modulus on a 1 / 4" thick sample at a crosshead speed of 2.8 mm / min in accordance with ASTM D790.

[0091] (5) Extrudability: Visually inspect the surface of each thermoplastic resin composition extruded in the form of a strand. When no breakage or discontinuity is observed in the strand despite the formation of agglomerates (protrusions) on the strand, the corresponding resin composition is evaluated as "good", while when any breakage or discontinuity is observed in the strand, the corresponding resin composition is evaluated as "poor".

[0092] Table 1

[0093]

[0094] Table 2

[0095]

[0096]

[0097] Table 3

[0098]

[0099] Table 4

[0100]

[0101] As can be seen from the above results, the thermoplastic resin composition according to the present invention has good properties in terms of flame retardancy (film flame retardancy and resistance to reignition), impact resistance (notched Izod impact strength), rigidity (flexural modulus), extrudability, etc.

[0102] Conversely, it can be seen that the thermoplastic resin composition of Comparative Example 1 prepared using an insufficient amount of glass fiber surface-treated with a polyolefin undergoes deterioration in impact resistance, rigidity, etc., the thermoplastic resin composition of Comparative Example 2 prepared using an excessive amount of glass fiber surface-treated with a polyolefin undergoes deterioration in flame retardancy (film flame retardancy and resistance to reignition), etc., and the thermoplastic resin composition of Comparative Example 3 prepared using glass fiber B2 instead of the glass fiber surface-treated with a polyolefin according to the present invention undergoes deterioration in impact resistance, rigidity, etc. It can be seen that the thermoplastic resin composition of Comparative Example 4 prepared using an insufficient amount of a phosphorus-nitrogen flame retardant undergoes deterioration in flame retardancy (film flame retardancy and resistance to reignition), rigidity, etc., the thermoplastic resin composition of Comparative Example 5 prepared using an excessive amount of a phosphorus-nitrogen flame retardant undergoes deterioration in impact resistance, extrudability, etc., the thermoplastic resin composition of Comparative Example 6 prepared using phosphorus-nitrogen flame retardant C4 instead of the phosphorus-nitrogen flame retardant according to the present invention undergoes deterioration in flame retardancy (film flame retardancy and resistance to reignition), impact resistance, etc., and the thermoplastic resin composition of Comparative Example 7 prepared using phosphorus-nitrogen flame retardant C5 undergoes deterioration in impact resistance, rigidity, extrudability, etc. In addition, it can be seen that the thermoplastic resin composition of Comparative Example 8 prepared using an insufficient amount of maleic anhydride-modified polypropylene undergoes deterioration in flame retardancy (film flame retardancy), impact resistance, rigidity, etc., the thermoplastic resin composition of Comparative Example 9 prepared using an excessive amount of maleic anhydride-modified polypropylene undergoes deterioration in flame retardancy (film flame retardancy), etc., and the thermoplastic resin composition of Comparative Example 10 prepared using maleic anhydride-modified polyethylene D2 instead of the maleic anhydride-modified polypropylene according to the present invention undergoes deterioration in flame retardancy (film flame retardancy), impact resistance, rigidity, extrudability, etc.

[0103] Although some embodiments have been described herein, those skilled in the art will understand that various modifications, changes, and variations can be made without departing from the spirit and scope of the present invention. Therefore, it should be understood that these embodiments are provided for illustration only and should not 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 preceding description, and the claims and their equivalents are intended to cover such modifications and the like that fall within the scope of the present invention.

Claims

1. A thermoplastic resin composition, comprising: About 100 parts by weight of a polypropylene resin; About 30 to about 45 parts by weight of glass fibers treated with a polyolefin; About 50 to about 60 parts by weight of a phosphorus-nitrogen flame retardant, which comprises about 70 wt% to about 90 wt% of piperazine pyrophosphate and about 10 wt% to about 30 wt% of melamine polyphosphate; and About 1.5 to about 4.5 parts by weight of maleic anhydride-modified polypropylene.

2. The thermoplastic resin composition according to claim 1, wherein the polypropylene resin comprises at least one of a homopolypropylene resin, a block polypropylene resin, and a random polypropylene resin.

3. The thermoplastic resin composition according to claim 1 or claim 2, wherein the glass fibers treated with a polyolefin have a polyolefin content of about 0.3 wt% to about 1.7 wt%.

4. The thermoplastic resin composition according to any one of claims 1 to 3, wherein the polyolefin of the glass fibers treated with a polyolefin comprises at least one of polypropylene and polyethylene.

5. The thermoplastic resin composition according to any one of claims 1 to 4, wherein the maleic anhydride-modified polypropylene has a graft degree of maleic anhydride in the range of about 0.5 wt% to about 3.0 wt%.

6. The thermoplastic resin composition according to any one of claims 1 to 5, wherein the maleic anhydride-modified polypropylene has a melt flow index of about 80 g / 10 min to about 140 g / 10 min measured at a temperature of 230 °C under a load of 2.16 kg according to ASTM D1238.

7. The thermoplastic resin composition according to any one of claims 1 to 6, wherein the weight ratio of the glass fibers treated with a polyolefin to the phosphorus-nitrogen flame retardant is in the range of about 1:1.2 to 1:

2.

8. The thermoplastic resin composition according to any one of claims 1 to 7, wherein the weight ratio of the maleic anhydride-modified polypropylene to the glass fibers treated with a polyolefin is in the range of about 1:10 to about 1:

20.

9. The thermoplastic resin composition according to any one of claims 1 to 8, wherein the weight ratio of the maleic anhydride-modified polypropylene to the phosphorus-nitrogen flame retardant is in the range of about 1:15 to about 1:

30.

10. The thermoplastic resin composition according to any one of claims 1 to 9, wherein the thermoplastic resin composition has a flame retardancy of V-0 or higher measured on an injection-molded sample with a thickness of 0.8 mm by the UL-94 vertical test method.

11. The thermoplastic resin composition according to any one of claims 1 to 10, wherein the thermoplastic resin composition has a glow wire ignition temperature (GWIT) of about 750 °C or higher measured on a sample having dimensions of 100 mm × 100 mm × 1.5 mm according to UL746A.

12. The thermoplastic resin composition according to any one of claims 1 to 11, wherein the thermoplastic resin composition has a notched Izod impact strength of about 4 kgf·cm / cm to about 8 kgf·cm / cm measured on a 1 / 8" thick sample in accordance with ASTM D256.

13. The thermoplastic resin composition according to any one of claims 1 to 12, wherein the thermoplastic resin composition has a flexural modulus of about 48,000 kgf / cm 2 to about 60,000 kgf / cm 2 measured on a 1 / 4" thick sample at a crosshead speed of 2.8 mm / min in accordance with ASTM D790.

14. A molded article made from the thermoplastic resin composition according to any one of claims 1 to 13.

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