JP-2026075276-A - Polycarbonate resin composition and molded article

Abstract

[Problem] To enable the use of recycled polycarbonate resin without degrading its properties such as hue, impact resistance, and defects. [Solution] A polycarbonate resin composition comprising 100 parts by weight of polycarbonate resin (component A), consisting of 1 to 99 parts by weight of recycled polycarbonate resin (component A-1) and 99 to 1 part by weight of non-recycled polycarbonate resin (component A-2), wherein (component A-1) has an ashing residue of 0 to 0.4% by weight after 3 hours at 600°C, and (component A-1) has a 5% weight loss temperature measured in a nitrogen atmosphere under a temperature increase of 20°C/min of 405°C to 505°C. [Selection Diagram] None

Inventors

• 鬼澤 大光
• 光永 正樹
• 柳本 直輝

Assignees

• 帝人株式会社

Dates

Publication Date

20260508

Application Date

20241022

Claims (5)

1. (A) A polycarbonate resin composition comprising 100 parts by weight of polycarbonate resin (component A), consisting of 1 to 99 parts by weight of recycled polycarbonate resin (component A-1) and 99 to 1 part by weight of non-recycled polycarbonate resin (component A-2), wherein component A has an ashing residue of 0 to 0.4% by weight after 3 hours at 600°C, and the temperature of the 5% weight loss of component A, measured under a temperature increase of 20°C/min in a nitrogen atmosphere, is 405°C to 505°C.
2. The polycarbonate resin composition according to claim 1, wherein component B is at least one phosphate-based stabilizer selected from the group consisting of (B-1) phosphonic acid ester (component B-1), (B-2) acidic phosphate ester (component B-2), and (B-3) phosphate metal salt (component B-3).
3. The polycarbonate resin composition according to claim 1, wherein the recycled polycarbonate resin (component A-1) is obtained by a manufacturing process comprising: (i) a step of crushing a recovered polycarbonate resin molded product equipped with one or more magnetic separation steps (crushing step); (ii) a step of washing the crushed material obtained in the crushing step (washing step); and (iii) an extrusion step of pelletizing the crushed and washed material obtained in the washing step by melt kneading (extrusion step).
4. The polycarbonate resin composition according to claim 1, comprising 0.1 to 100 parts by weight of a thermoplastic resin other than polycarbonate resin (component C) per 100 parts by weight of polycarbonate resin (component A).
5. A molded article formed from the polycarbonate resin composition described in any one of claims 1 to 4.

Description

This invention relates to a polycarbonate resin composition and molded article that enables high-level property maintenance, containing recycled polycarbonate resin having a specific ashing residual amount and weight loss temperature, non-recycled polycarbonate resin, and a phosphate-based stabilizer. Thermoplastic resin compositions are used in a wide range of fields, including casings and components for electrical, electronic, and office automation equipment, interior and exterior parts for automobiles, furniture, musical instruments, and general merchandise. In recent years, in particular, high recyclability of thermoplastic resin compositions has become desirable for the realization of a sustainable society. Polycarbonate resin, in particular, is an expensive material, and recycling it reduces the consumption of new resources and promotes sustainable resource use. Therefore, the use of recycled polycarbonate resin has become an important social responsibility. On the other hand, the use of recycled polycarbonate resin has been difficult due to significant degradation of its properties upon recycling. A major problem with recycled polycarbonate resin is reduced transparency, and the increase in defects due to foreign matter contamination is particularly critical for transparent polycarbonate resin, making problem-solving crucial. Reduced thermal stability is also a significant issue. Furthermore, the use of phosphorus-based compounds as thermal stabilizers in polycarbonate resin compositions is widely known. Patent Document 1 discloses the use of specific phosphorus-based compounds in resins composed of polycarbonate-based resins and polyester resins. Patent Document 2 discloses the combined use of phosphorus-based compounds. However, existing methods have not yet reached a level that enables the use of recycled polycarbonate resin, and its use is strongly desired. Patent No. 4983427Patent No. 5640734 The details of this invention will be described below. <Component A: Polycarbonate resin> The polycarbonate resin used as component A in this invention is obtained by reacting a divalent phenol with a carbonate precursor. Examples of reaction methods include interfacial polymerization, molten transesterification, solid-phase transesterification of carbonate prepolymers, and ring-opening polymerization of cyclic carbonate compounds. Typical examples of divalent phenols used here include hydroquinone, resorcinol, 4,4'-biphenol, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A), 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 2,2-bis(4-hydroxyphenyl)pentane, and 4,4'-(p-phenyl Examples include bis(4-hydroxyphenyl)diphenol, 4,4'-(m-phenylenediisopropylpyridene)diphenol, 1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane, bis(4-hydroxyphenyl)oxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)ketone, bis(4-hydroxyphenyl)ester, bis(4-hydroxy-3-methylphenyl)sulfide, 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene. Preferred divalent phenols are bis(4-hydroxyphenyl)alkanes, with bisphenol A being particularly preferred and widely used due to its impact resistance. In this invention, in addition to bisphenol A-based polycarbonate resins, which are general-purpose polycarbonate resins, it is also possible to use special polycarbonate resins manufactured using other divalent phenols as component A. For example, polycarbonate resins (homopolymers or copolymers) using 4,4'-(m-phenylenediisopropylidene)diphenol (hereinafter sometimes abbreviated as "BPM"), 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (hereinafter sometimes abbreviated as "Bis-TMC"), 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (hereinafter sometimes abbreviated as "BCF") as part or all of the divalent phenol components are suitable for applications where dimensional changes due to water absorption and morphological stability are particularly demanding. It is preferable that these divalent phenols other than BPA be used in an amount of 5 mol% or more, particularly 10 mol% or more, of the total divalent phenol components constituting the polycarbonate resin. In particular, when high rigidity and better hydrolysis resistance are required, it is especially preferable that component A constituting the resin composition be one of the copolymer polycarbonate resins (1) to (3) below. (1) A copolymer polycarbonate resin in which, of 100 mol% of the divalent phenol component constituting the polycarbonate resin, BPM is 20 to 80 mol% (more preferably 40 to 75 mol%, even more preferably 45 to 65 mol%) and BCF is 20 to 80 mol% (more preferably 25 to 60 mol%, even more preferably 35 to 55 mol%). (2)