Thermoplastic resin composition having high rigidity and low coefficient of linear thermal expansion and molded article comprising same

Patent metadata

Field	Value
Publication number	US-11993702-B2
Application number	US-202217858378-A
Country	US
Kind code	B2
Filing date	Jul 6, 2022
Priority date	Jul 6, 2021
Publication date	May 28, 2024
Grant date	May 28, 2024

Abstract

The present disclosure provides a thermoplastic resin composition having high rigidity and a low coefficient of linear thermal expansion and a molded article including the same. Specifically, the thermoplastic resin composition includes a base resin including at least two polypropylene-based resins having different melt indexes, an elastomer having a melt index (190° C., 2.16 kg) of 20 g/10 min to 35 g/10 min as measured by ASTM D1238, and inorganic particles, and has a flexural modulus (FM) of 2,500 MPa or more and a coefficient of linear thermal expansion (CLTE) of 60 μm/m° C. or less.

First claim

The invention claimed is:

1. A thermoplastic resin composition comprising:
a base resin comprising a first polypropylene-based resin having a melt index (230° C., 2.16 kg) of 90 g/10 min to 110 g/10 min as measured by ASTM D1238, and a second polypropylene-based resin having a melt index (230° C., 2.16 kg) of 50 g/10 min to 70 g/10 min as measured by ASTM D1238;
an elastomer having a melt index (190° C., 2.16 kg) of 20 g/10 min to 35 g/10 min as measured by ASTM D1238; and
inorganic particles.

2. The thermoplastic resin composition of claim 1 , wherein each of the first polypropylene-based resin and the second polypropylene-based resin comprises at least one selected from the group consisting of: homo-polypropylene, a copolymer of propylene and α-olefin having 2 and 4 to 20 carbon atoms, and combinations thereof.

3. The thermoplastic resin composition of claim 1 , wherein the base resin comprises the first polypropylene-based resin and the second polypropylene-based resin at a weight ratio of 1:0.2 to 1:0.6.

4. The thermoplastic resin composition of claim 1 , wherein the elastomer comprises a copolymer of ethylene and α-olefin having 3 to 8 carbon atoms.

5. The thermoplastic resin composition of claim 1 , wherein the inorganic particles comprise at least one selected from the group consisting of: talc, mica, calcium carbonate, wollastonite, clay, magnesium sulfate, whiskers, and combinations thereof.

6. The thermoplastic resin composition of claim 1 , wherein the inorganic particles have an average diameter of 1 μm to 3 μm.

7. The thermoplastic resin composition of claim 1 , comprising:
50 wt % to 60 wt % of the base resin;
15 wt % to 30 wt % of the elastomer; and
20 wt % to 35 wt % of the inorganic particles.

8. The thermoplastic resin composition of claim 1 , further comprising at least one nucleating agent selected from the group consisting of: a cyclohexane dicarboxylic acid metal salt, metal stearate, and combinations thereof.

9. The thermoplastic resin composition of claim 1 , further comprising at least one additive selected from the group consisting of: an antioxidant, an ultraviolet absorber, a nucleating agent, a coupling agent, a dispersant, a light stabilizer, a processing lubricant, a slipping agent, an antistatic agent, an inorganic pigment, and combinations thereof.

10. A molded article comprising the thermoplastic resin composition of claim 1 .

11. The molded article of claim 10 , wherein IZOD impact strength measured at 23° C. according to ASTM D256 is 320 J/m or more and IZOD impact strength measured at −30° C. is 45 J/m or more.

12. The molded article of claim 10 , wherein tensile strength measured according to ASTM D638 is 17 MPa or more.

13. The molded article of claim 10 , wherein the molded article is at least one automobile exterior material selected from the group consisting of: a side sill molding, door molding, fender molding, quarter glass molding, roof rack, side outer garnish, roof molding garnish, back panel molding, tailgate garnish, and combinations thereof.

Assignees

• Hyundai Motor Co Ltd
• Kia Corp
• Lotte Chemical Corp

Inventors

• Yoon Jin Young
• Lee Hee Joon
• Cha Dong Eun
• Kwon Sun Jun
• Park Chun Ho
• Jeong Seung Ryong
• Lim Kyung Hwan
• Jang Eun Hwa

Classifications

• C08L23/16 Primary

  Ethylene-propylene or ethylene-propylene-diene copolymers · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• C08L2205/03

  containing three or more polymers in a blend · CPC title

• C08L2205/06

  having improved processability or containing aids for moulding methods · CPC title

• C08L2205/24

  Crystallisation aids · CPC title