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WO-2026094936-A1 - THERMOPLASTIC POLYESTER RESIN COMPOSITION FOR FOAM MOLDING, AND FOAM MOLDED ARTICLE

WO2026094936A1WO 2026094936 A1WO2026094936 A1WO 2026094936A1WO-2026094936-A1

Abstract

The present disclosure addresses the problem of providing a polyester resin composition suitable for mold expansion methods such as foam molding, particularly core-back foam injection molding. A thermoplastic polyester resin composition for foam molding according to the present disclosure contains a crystalline polyester (A1), a crystalline polyester (A2) other than the crystalline polyester (A1) and/or an amorphous polyester (B), and a glycidyl-group-containing styrene copolymer (C), and furthermore contains, as needed, an inorganic reinforcing material (D), wherein: in a total of 100 mass parts of (A1), (A2), (B), and (C), (A1) is 60 parts by mass or more, (A2) is 0-40 parts by mass, (B) is 0-30 parts by mass, (A2) and (B) are a total of 5 parts by mass or more, and (C) is 0.1-7 parts by mass; (D) is 0-100 parts by mass relative to a total of 100 mass parts of (A1), (A2), (B), and (C); and the thermoplastic polyester resin composition for foam molding satisfies formula (1).　Formula (1): Tm − Tc2 ≥ 30°C

Inventors

  • FUJII, YASUTO
  • SHIMOHARAI, Takuya
  • OKAJIMA, Hiroki

Assignees

  • 東洋紡エムシー株式会社

Dates

Publication Date
20260507
Application Date
20251029
Priority Date
20241031

Claims (15)

  1. Crystalline polyester (A1), Crystalline polyester (A2) other than the crystalline polyester (A1), and/or amorphous polyester (B), It contains a glycidyl group-containing styrene copolymer (C), Furthermore, a thermoplastic polyester resin composition containing an inorganic reinforcing material (D) as needed, In a total of 100 parts by mass of the crystalline polyester (A1), the crystalline polyester (A2), the amorphous polyester (B), and the glycidyl group-containing styrene copolymer (C), 60 parts by mass or more of the crystalline polyester (A1), The crystalline polyester (A2) 0 to 40 parts by mass, The amorphous polyester (B) is 0 to 30 parts by mass, and the total amount of the crystalline polyester (A2) and the amorphous polyester (B) is 5 parts by mass or more. The glycidyl group-containing styrene copolymer (C) is 0.1 to 7 parts by mass, The inorganic reinforcing material (D) is present in an amount of 0 to 100 parts by mass per 100 parts by mass of the total of the crystalline polyester (A1), the crystalline polyester (A2), the amorphous polyester (B), and the glycidyl group-containing styrene copolymer (C). A thermoplastic polyester resin composition for foam molding that satisfies the following formula (1). Tm-Tc2≧30℃ (1) During the ceremony, Tm (°C): Melting point of thermoplastic polyester resin composition determined by differential scanning calorimeter (DSC) Tc2 (°C): Cooling crystallization temperature of thermoplastic polyester resin composition determined by differential scanning calorimeter (DSC)
  2. The thermoplastic polyester resin composition for foam molding according to claim 1, wherein the crystalline polyester (A1) mainly comprises terephthalic acid or a derivative thereof as a polycarboxylic acid component, and mainly comprises a linear aliphatic polyhydric alcohol having 4 or fewer carbon atoms, or a polyhydric alcohol having 6 or more carbon atoms with an alicyclic skeleton as a polyhydric alcohol component.
  3. The thermoplastic polyester resin composition for foam molding according to claim 1, wherein the crystalline polyester (A2) is polyethylene terephthalate or polybutylene terephthalate, which may be copolymers.
  4. The thermoplastic polyester resin composition for foam molding according to claim 1, wherein the amorphous polyester (B) is copolymerized polyethylene terephthalate.
  5. The thermoplastic polyester resin composition for foam molding according to claim 2, wherein the crystalline polyester (A1) is a copolymerized polyester obtained by copolymerizing dimerol as the diol component.
  6. The thermoplastic polyester resin composition for foam molding according to claim 2, wherein the crystalline polyester (A1) is polybutylene terephthalate.
  7. The thermoplastic polyester resin composition for foam molding according to claim 2, wherein the crystalline polyester (A1) is a copolymer of polybutylene terephthalate or polycyclohexylene dimethylene terephthalate and dimergol.
  8. The thermoplastic polyester resin composition for foam molding according to claim 3, wherein the crystalline polyester (A2) is a copolymerized polyester obtained by copolymerizing an aromatic dicarboxylic acid other than terephthalic acid as the dicarboxylic acid component.
  9. The thermoplastic polyester resin composition for foam molding according to claim 3, wherein the crystalline polyester (A2) is a copolymer of polybutylene terephthalate and isophthalic acid.
  10. The thermoplastic polyester resin composition for foam molding according to claim 4, wherein the amorphous polyester (B) is copolymerized polyethylene terephthalate obtained by copolymerizing an aliphatic diol having a branched chain structure as the diol component.
  11. The thermoplastic polyester resin composition for foam molding according to claim 4, wherein the amorphous polyester (B) is a copolymer of polyethylene terephthalate and neopentyl glycol.
  12. The thermoplastic polyester resin composition for foam molding according to claim 1, wherein the glycidyl group-containing styrene copolymer (C) is a copolymer containing a vinyl aromatic monomer and a glycidyl alkyl (meth)acrylate as constituent units.
  13. The thermoplastic polyester resin composition for foam molding according to claim 12, wherein the vinyl aromatic monomer is styrene and the glycidyl alkyl (meth)acrylate is glycidyl acrylate.
  14. A foamed molded article obtained by molding a thermoplastic polyester resin composition for foam molding according to any one of claims 1 to 13, The foamed molded body is a foamed molded body having non-foamed skin layers on both sides of the foamed layer.
  15. An in-vehicle component formed by molding a thermoplastic polyester resin composition for foam molding according to any one of claims 1 to 13.

Description

Thermoplastic polyester resin composition for foam molding, and foam molded product This invention relates to a thermoplastic polyester resin composition for foam molding, and to an automotive component obtained by foam molding of the thermoplastic polyester resin composition. To improve fuel efficiency, automobiles have traditionally undergone weight reduction measures, such as replacing metal parts with resin molded parts. For example, resin molded parts are used in many in-vehicle components, including exterior panels, engine-related parts, mechanical parts, door trim, dashboard, console, instrument panel, monitors, and switches. Further weight reduction of these resin molded parts is also being considered. As a technology to achieve weight reduction in resin molded products, parts made by foam molding of resin (foamed molded products) are being considered. Foam molding creates a cellular structure inside the resin, which reduces the amount of resin used, thus making the parts lighter compared to non-foamed molded products. Furthermore, from the perspective of improving recyclability, foamed molded products using thermoplastic polyester resin compositions (hereinafter referred to as polyester resin compositions) are being considered. For example, Patent Document 1 discloses a polyester resin composition suitable for foam molding and a foam molded product. In recent years, foamed molded products with a sandwich structure consisting of a non-foamed skin layer on the surface and a foamed layer inside have attracted attention as foamed molded products with excellent appearance. Figure 1 is a schematic diagram illustrating an example of a method for producing a foamed molded article obtained by foaming the thermoplastic polyester resin composition of the present invention.Figure 2 is a photograph showing the foaming state of the cross-section of the foamed molded body of the example. The thermoplastic polyester resin composition of this disclosure (hereinafter referred to as the polyester resin composition), which is suitable for foam molding, contains predetermined amounts of a crystalline polyester (A1), a crystalline polyester (A2) different from the crystalline polyester (A1) and/or an amorphous polyester (B), and a glycidyl group-containing styrene copolymer (C), and may optionally contain a predetermined amount of an inorganic reinforcing material (D). Furthermore, the polyester resin composition has a melting point Tm (°C) and a cooling crystallization temperature Tc2 (°C) (sometimes called the crystallization temperature) that satisfy the following formula (1). Tm-Tc2≧30℃ (1) A foamed molded article having a sandwich structure with a non-foamed skin layer on the surface and a foamed layer inside (hereinafter referred to as a foamed molded article) is formed by a mold expansion method such as core-back injection foam molding. However, in order to achieve good foam moldability and appearance, it is necessary to appropriately adjust not only the composition of the polyester resin composition, but also the melting point Tm (°C) and crystallization temperature Tc2 (°C) of the polyester resin composition, as described below. In this disclosure, foam moldability refers to the ability to fill a mold and the foamed state, and in preferred embodiments, it may include the ability to conform to the shape of the foamed portion and the ability to release it from the mold. Appearance refers to the absence of blistering, silvering, flashing, and swirl marks on the surface of the foamed molded product. In particular, if the foamed molded product contains inorganic reinforcing materials, it is preferable that there is no silvering, flashing, swirl marks, or lifting of the inorganic reinforcing materials on the surface of the foamed molded product. The polyester resin composition of this disclosure contains two or more polyesters. The two or more polyesters consist of a crystalline polyester (A1) as the main component (60 parts by mass or more), a crystalline polyester (A2) other than crystalline polyester (A1), and/or amorphous polyester (B) as minor components. This allows the crystallization rate of the rapidly crystallizing crystalline polyester (A1) to be reduced by the crystalline polyester (A2) and/or amorphous polyester (B), thereby controlling the crystallization rate to satisfy formula (1) above, and improving foam moldability and appearance. Even when the crystallization rate of the slow-crystallizing crystalline polyester (A1) is increased by the crystalline polyester (A2) and/or amorphous polyester (B) to control the crystallization rate so as to satisfy the above formula (1), foam moldability and appearance can be improved. In this disclosure, "crystalline polyester (A2) other than crystalline polyester (A1)" means that crystalline polyester (A1) and crystalline polyester (A2) have different compositions. Of the two types of crystalline polyester, one with a higher content may be crystalline polyester (A1)