KR-102962352-B1 - Paint compositions, coating films, and coated articles

Abstract

A paint composition is provided that does not use N-methyl-2-pyrrolidone and has performance similar to that of the prior art. The paint composition comprises polytetrafluoroethylene, a polyamideimide resin, and a filler, and is substantially free of N-methyl-2-pyrrolidone. The filler has a hardness of 7 to 12 on the New Mohs hardness scale and a primary particle size of 1 μm or less. The filler content is 10 to 30 parts by mass per 100 parts by mass of the solid content of the polyamideimide resin in the paint composition. The viscosity of the paint composition is 10,000 to 20,000 cps, and the dispersion of the paint, measured according to JIS K5600 using a grind gauge, is 5 μm or less.

Inventors

• 니시무라 히로시
• 가도와키 유
• 나카타니 야스카즈

Assignees

• 다이킨 고교 가부시키가이샤

Dates

Publication Date

20260512

Application Date

20210706

Priority Date

20200709

Claims (8)

1. A paint composition comprising polytetrafluoroethylene, polyamideimide resin and filler, and substantially not comprising N-methyl-2-pyrrolidone, It comprises at least one solvent selected from the group consisting of N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, and N-butyl-2-pyrrolidone, and The above filler has a hardness of 7 to 12 on the New Mohs hardness scale and a primary particle size of 1 μm or less, and The filler content is 10 to 30 parts by mass with respect to 100 parts by mass of the solid content of the polyamideimide resin in the paint composition, and The viscosity of the paint composition is 10,000 to 20,000 cps, and A paint composition characterized by a dispersion degree of 5㎛ or less as measured according to JIS K5600 using a grind gauge.
2. In paragraph 1, A paint composition in which the above filler is at least one selected from the group consisting of aluminum oxide and silicon dioxide.
3. In paragraph 1 or 2, Additionally, a paint composition comprising at least one resin selected from the group consisting of polyethersulfone (PES), polyetheretherketone (PEEK), and polyimide (PI).
4. In paragraph 1 or 2, Paint composition for automotive air conditioner compressor pistons.
5. A coating film characterized by being formed from a paint composition described in claim 1 or 2.
6. In paragraph 5, A coating with a wear resistance of 100 or higher.
7. A coated article characterized by having a coating film on its surface as described in paragraph 5.
8. delete

Description

Paint compositions, coating films, and coated articles The present disclosure relates to paint compositions, coating films, and coated articles. Polyamideimide resin is a resin classified as a super engineering plastic that possesses excellent performance, including high heat resistance, maintaining wear resistance and sliding characteristics even at high temperatures, and excellent dimensional stability. Patent Document 1 discloses a composition containing polyamideimide resin and polytetrafluoroethylene, using β-alkoxypropionamide solvent as a solvent. Patent document 2 discloses the use of 3-methoxy-N,N-dimethylpropanamide as a solvent for dissolving polyamideimide. Patent document 3 discloses a heat-resistant resin composition comprising a polyamideimide resin and an amide solvent. The present disclosure will be described in detail below. Conventionally, when polyamideimide resins are used as binder resins in paint compositions, those containing N-methyl-2-pyrrolidone as a solvent have been used. Since N-methyl-2-pyrrolidone is a resin with excellent solubility, using it has made it possible to obtain suitable paint compositions. In recent years, paint compositions that do not use N-methyl-2-pyrrolidone have been requested from various perspectives. For this reason, the use of other solvents that dissolve polyamideimide resins, such as those described in Patent Documents 1 to 3, has been proposed. However, paint compositions that do not use N-methyl-2-pyrrolidone require the use of low molecular weight resins compared to cases where N-methyl-2-pyrrolidone is used. This is because high molecular weight resins become sparingly soluble due to the reduced solubility of the solvent. Since lowering the molecular weight results in a decrease in performance such as strength and durability, there was a demand to improve these aspects and obtain performance equivalent to conventional paint compositions without using N-methyl-2-pyrrolidone. It is important that the paint composition of the present disclosure has a dispersion degree of 5 μm or less, as measured according to JIS K5600 using a grind gauge. Powder components incorporated into paint compositions tend to cause aggregation in the powder state, making it prone to containing coarse aggregated particles. In the paint composition of the present disclosure, the aggregated particles are broken down, thereby improving the above problem by making the dispersion of the paint, measured according to JIS K5600, 5 μm or less. That is, the above problem is improved by making both polytetrafluoroethylene and filler, which are powder components included in the paint composition, into particles that have been sufficiently broken down. Although the mechanism by which these effects are obtained is not clear, it is presumed that by dispersing with a low degree of dispersion, a highly uniform composition is obtained, enabling the formation of a uniform coating film and thereby improving the physical properties of the coating film. The dispersion of the paint measured according to JIS K5600 using a grind gauge is a value measured based on the specifications of the said JIS. It is more preferable that the above dispersion is 5㎛ or less. A composition having a dispersion degree of 5 μm or less can be obtained by sufficiently performing a treatment to break down particles when preparing a paint. The present disclosure is a paint composition comprising polytetrafluoroethylene, a polyamideimide resin, and a filler, and substantially not containing N-methyl-2-pyrrolidone. Each component included is described below. (Polytetrafluoroethylene) Polytetrafluoroethylene (hereinafter referred to as PTFE) is a polymer of tetrafluoroethylene. The above PTFE may be a homo PTFE containing only TFE units, or a modified PTFE containing TFE units and modified monomer units based on modified monomers copolymerizable with TFE. Furthermore, it is preferable that the above PTFE be a low molecular weight PTFE that has melt processability and does not have fibrillation properties. The above-mentioned modified monomer is not particularly limited as long as it is capable of copolymerizing with TFE, and examples include perfluoroolefins such as hexafluoropropylene [HFP]; chlorofluoroolefins such as chlorotrifluoroethylene [CTFE]; hydrogen-containing fluoroolefins such as trifluoroethylene and vinylidene fluoride [VDF]; perfluorovinyl ethers; perfluoroalkylethylene; ethylene; and fluorine-containing vinyl ethers having nitrile groups. In addition, the modified monomer used may be one type or multiple types. The above perfluorovinyl ether is not particularly limited, for example, the following general formula (1) CF 2 =CF-ORf 1 (1) Examples include perfluorounsaturated compounds expressed as (wherein Rf 1 represents a perfluoro organic group). In this specification, the term "perfluoro organic group" refers to an organic group formed in which all hydrogen atoms bonded to carbon atoms are replaced by fluori