KR-20260063961-A - POLYPROPYLENE RESIN COMPOSITION WITH EXCELLENT WELD PERFORMANCE AND MOLDED PRODUCT FORMED THEREFROM

Abstract

The present invention relates to a polypropylene resin composition with excellent weld performance and a molded article thereof. More specifically, the present invention can provide a polypropylene resin composition and a molded article thereof that improve weld strength and weld elongation by using a styrene-based rubber (styrene-based elastomer).

Inventors

• 유재정
• 서하규
• 김용범
• 조용석

Assignees

• 지에스칼텍스 주식회사

Dates

Publication Date

20260507

Application Date

20241031

Claims (19)

1. (A) Polypropylene resin; (B) Styrene rubber; (C) Olefin rubber; and (D) Includes a lubricant; and Polypropylene resin composition.
2. In paragraph 1, The above (A) polypropylene resin composition is a polypropylene resin having a melt index of 20 g/10 min to 40 g/10 min at a temperature of 230°C and a load of 2.16 kg.
3. In paragraph 1, The above (B) styrene-based rubber comprises at least one of styrene-butylene-styrene, styrene-ethylene-butylene-styrene, styrene-ethylene-propylene-styrene, styrene-ethylene-ethylene-propylene-styrene, styrene-butadiene-styrene, styrene-ethylene-butadiene-styrene rubber, styrene-isoprene-styrene, and styrene-isoprene-butadiene-styrene copolymer, and isopropyl-styrene resin composition.
4. In paragraph 3, The above (B) styrene-based rubber comprises (B-1) styrene-butadiene-styrene rubber and (B-2) styrene-ethylene-butadiene-styrene rubber, a polypropylene resin composition.
5. In paragraph 1, The above (C) olefin-based rubber comprises at least one of (C-1) octene-based rubber and (C-2) butene-based rubber, and is a polypropylene resin composition.
6. In paragraph 5, The above (C) olefin-based rubber is a polypropylene resin composition comprising (C-1) octene-based rubber.
7. In paragraph 4, The above (C) olefin-based rubber is a polypropylene resin composition comprising (C-2) butene-based rubber.
8. In paragraph 1, The above (D) lubricant comprises at least one of a fatty acid amide-based lubricant and silicone gum, in a polypropylene resin composition.
9. In paragraph 1, A polypropylene resin composition comprising 30 to 60 weight% of the (A) polypropylene resin, based on 100 weight% of the above polypropylene resin composition.
10. In paragraph 4, With respect to 100 weight% of the above polypropylene resin composition, A polypropylene resin composition comprising 20 to 30 weight% of the (B-1) styrene-butadiene-styrene rubber and 1 to 5 weight% of the (B-2) styrene-ethylene-butadiene-styrene rubber.
11. In paragraph 6, A polypropylene resin composition comprising 1 to 45 weight% of the (C-1) octene-based rubber, based on 100 weight% of the above polypropylene resin composition.
12. In Paragraph 7, A polypropylene resin composition comprising 1 to 25 weight% of the (C-2) butene-based rubber, based on 100 weight% of the polypropylene resin composition.
13. In paragraph 1, A polypropylene resin composition comprising 0.1 to 5 weight% of the (D) lubricant based on 100 weight% of the above polypropylene resin composition.
14. A molded article formed from a polypropylene resin composition according to any one of claims 1 to 13.
15. In Paragraph 14, The above molded article is a molded article having a weld elongation of 50% or more as measured by the ISO 527 method.
16. In Paragraph 14, The above molded article is a molded article having a weld strength of 17 MPa or higher as measured by the ISO 527 method.
17. In paragraph 1, The above molded product is 230 according to the ISO 1133 method A molded article having a melt index of 3.0 g/10 min or higher measured under temperature conditions and a load of 2.16 kg.
18. In paragraph 1, The above molded article is a molded article having a tensile strength of 15 MPa or more as measured by the ISO 37-1A method.
19. In paragraph 1, The above molded article is a molded article having a flexural modulus of 370 MPa or higher as measured by the ISO 178 method.

Description

Polypropylene resin composition with excellent weld performance and molded product formed therefrom The present invention relates to a polypropylene resin composition with excellent weld performance and a molded article formed therefrom. More specifically, the present invention relates to a polypropylene resin composition that improves weld strength and weld elongation by including a polypropylene resin and a styrene-based and olefin-based rubber composite resin, and a molded article formed therefrom. Plastics used in automotive plastic safety parts require reliability not only at room temperature but also at low and high temperatures. Therefore, olefinic resins, known for their stable physical properties at both low and high temperatures, are used. However, olefin-based resins had a problem where the weld area cracked, i.e., a weld line occurred. In the case of composite resins rather than single-phase resins, there was a problem that led to performance degradation, such as a decrease in the mechanical strength of the final product, due to the degradation of physical properties such as weld strength and weld elongation at the point where the resins meet (weld point). For example, referring to Figures 1 and 2, the top view and side view of the weld strength evaluation specimen shape according to ISO 527 show resins filled from both gates and meeting in the center, and a tensile specimen is briefly shown indicating the part where performance degradation occurs at the interface (weld point) where the two sides meet (an example of cracking at the interface is shown in the center of Figure 1). Figure 2 schematically shows the filling of resin over time, and indicates that the resin is filled from the part marked in blue in the direction of the part marked in red. The physical properties at such weld lines vary significantly depending on product molding conditions. Since performance degradation at the weld site cannot be avoided with conventional compositions, the weld location was intentionally controlled through design or processing methods. However, this method presents a problem in that it is difficult to secure the degree of freedom in mold design. Therefore, apart from researching mold design and injection molding methods to prevent weld formation, there is a growing need to develop resin compositions that can improve weld strength and weld elongation while satisfying target mechanical properties. Figure 1 is a top view and side view of the weld strength evaluation specimen shape according to ISO 527. Figure 2 shows the resin filling pattern over time of a weld strength evaluation specimen shape according to ISO 527 in a shaded type, where the resin is filled from the part marked in blue to the part marked in red, and the temperature increases in the center as the resin is filled. The aforementioned objectives, features, and advantages are described in detail below with reference to the attached drawings, thereby enabling those skilled in the art to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions would unnecessarily obscure the essence of the invention. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals are used to indicate the same or similar components. Where terms such as "comprising," "having," "consisting of," "arranging," or "having" are used for a component in this specification, other parts may be added unless "only" is used. Where a component is expressed in the singular, it includes cases where it is included in the plural unless specifically stated otherwise. In interpreting the components in this specification, they are interpreted to include an error range even if there is no separate explicit description. In this specification, the standard for units is weight (wt) unless otherwise specifically stated. For example, if "%" is indicated, it is interpreted as weight % (wt%). In this specification, unless otherwise specifically stated, the melt index refers to the melt index measured in accordance with ISO 1133. The present invention will be described in more detail below. [Polypropylene resin composition] A polypropylene resin composition according to one embodiment of the present invention may comprise (A) polypropylene resin; (B) styrene-based rubber; (C) olefin-based rubber; and (D) a lubricant. (A) Polypropylene resin The polypropylene resin of the present invention may have a melt index of 20 g/10 min to 40 g/10 min when measured under a temperature condition of 230°C and a load condition of 2.16 kg. If the melt index is less than 20 g/10 min, there may be a problem with reduced flowability and injection properties, and if it exceeds 40 g/10 min, there may be a problem with red