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EP-4737091-A1 - MOLDED POLYCHLOROTRIFLUOROETHYLENE OBJECT AND PRODUCTION METHOD THEREFOR

EP4737091A1EP 4737091 A1EP4737091 A1EP 4737091A1EP-4737091-A1

Abstract

Provided is a formed article including polychlorotrifluoroethylene, wherein the polychlorotrifluoroethylene has a melting point of 211 to 216°C, and the formed article has a projected area of 1,000 mm 2 or more, a thickness of 25 to 50 mm, and a degree of crystallinity of 65% or less.

Inventors

  • IMAMURA, HITOSHI
  • YAMAZAKI, KEIKO
  • HAMADA, HIROYUKI
  • FUNAOKA, Misato
  • MUKAI, ERI
  • FUJISAWA, MANABU

Assignees

  • Daikin Industries, Ltd.

Dates

Publication Date
20260506
Application Date
20240625

Claims (7)

  1. A formed article comprising a polychlorotrifluoroethylene, wherein the polychlorotrifluoroethylene has a melting point of 211 to 216°C, and the formed article has a projected area of 1,000 mm 2 or more, a thickness of 25 to 50 mm, and a degree of crystallinity of 65% or less.
  2. The formed article according to claim 1, wherein the polychlorotrifluoroethylene is a homopolymer of chlorotrifluoroethylene.
  3. The formed article according to claim 1 or 2, wherein the flow value of the polychlorotrifluoroethylene measured at 230°C is 2.0 × 10 -3 ml/sec or less.
  4. The formed article according to any one of claims 1 to 3, wherein the formed article is a turntable of a semiconductor cleaning apparatus.
  5. The formed article according to any one of claims 1 to 4, wherein the formed article has a projected area of 10,000 to 300,000 mm 2 , a thickness of 25 to 44 mm, and a degree of crystallinity of 52 to 65%, and the flow value of the polychlorotrifluoroethylene measured at 230°C is 1.0 × 10 -3 to 2.0 × 10 -3 ml/sec.
  6. A method for producing the formed article according to any one of claims 1 to 5, the method comprising: heating a mold with a heater, charging the polychlorotrifluoroethylene into the mold, and compression molding the polychlorotrifluoroethylene in the mold to obtain the formed article, wherein the temperature of the heater is set to 290 to 325°C, and the heating time by the heater and the temperature of the heater are adjusted so as to satisfy the following relational expression (X): (Heating time by heater (min)) < [1176 - 3.31 × (Temperature of heater (°C))].
  7. The method according to claim 6, wherein a rate of change in flow value calculated by the following equation is 3.0 or less: Rate of change in flow value = F 1 − F 0 / F 0 F 0 : Flow value of the polychlorotrifluoroethylene before being charged into the mold F 1 : Flow value of the polychlorotrifluoroethylene forming the formed article.

Description

TECHNICAL FIELD The present disclosure relates to a formed article of polychlorotrifluoroethylene and a method for producing the same. BACKGROUND ART Patent Document 1 discloses a thermoplastic copolymer consisting essentially of chlorotrifluoroethylene and containing 0.5 to 6 mol% of vinylidene fluoride. RELATED ART PATENT DOCUMENTS Patent Document 1: U.S. Patent No. 2738343 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION An object of the present disclosure is to provide a formed article which is less likely to develop cracks even when tightened with strong force. Another object of the present disclosure is to provide a method for producing a formed article which is less likely to develop cracks even when tightened with strong force. MEANS FOR SOLVING THE PROBLEM According to the present disclosure, a formed article comprising a polychlorotrifluoroethylene, wherein the polychlorotrifluoroethylene has a melting point of 211 to 216°C, and the formed article has a projected area of 1,000 mm2 or more, a thickness of 25 to 50 mm, and a degree of crystallinity of 65% or less is provided. EFFECTS OF INVENTION According to the present disclosure, a formed article which is less likely to develop cracks even when tightened with strong force can be provided. Furthermore, according to the present disclosure, a method for producing a formed article which is less likely to develop cracks even when tightened with strong force can be provided. BRIEF DESCRIPTION OF DRAWINGS Figure 1 is a graph plotting the temperature of a heater and heating time in the method for producing the formed articles of Experimental Examples 1 to 6 and Comparative Examples 1 to 3.Figure 2 is a schematic diagram illustrating a crack resistance test method. Fig. 2(a) is a front schematic view of a sample sheet clamped between a bolt, washer, and nut. Fig. 2(b) is a top schematic view of a sample sheet clamped between a bolt, washer, and nut. DESCRIPTION OF EMBODIMENTS Hereinafter, specific embodiments of the present disclosure will be described in detail; however, the present disclosure is not limited to the following embodiments. Patent Document 1 discloses that although polychlorotrifluoroethylene containing 0.5 to 6 mol% of vinylidene fluoride exhibits the chemical and physical properties of a homopolymer of chlorotrifluoroethylene, the resulting film has high gloss, smoothness, and reduced brittleness. A homopolymer of chlorotrifluoroethylene (CTFE) has the advantage of being formable with high dimensional accuracy as compared with copolymers of CTFE described in Patent Document 1. However, it has been found that when formed into a thick formed article having a large projected area, the resulting formed article tends to crack under a large tightening force. As a result of intensive studies to solve the above problem, it has now been found that by selecting polychlorotrifluoroethylene (PCTFE) having a specific melting point and adjusting the degree of crystallinity of the formed article to fall within a specific range, a formed article having a large projected area and thick wall, or a thin-walled portion machined from the formed article, which is less likely to develop cracks even when tightened with strong force can be obtained, even when the PCTFE contains a homopolymer of CTFE. That is, the formed article of the present disclosure comprises PCTFE, wherein the PCTFE has a melting point of 211 to 216°C, and the formed article has a projected area of 1,000 mm2 or more, a thickness of 25 to 50 mm, and a degree of crystallinity of 65% or less. Next, the formed article of the present disclosure will be described in detail. (Formed Article) The formed article of the present disclosure is a thick formed article having a large projected area. The projected area of the formed article is 1,000 mm2 or more, preferably 5,000 mm2 or more, more preferably 10,000 mm2 or more, still more preferably 50,000 mm2 or more, and particularly preferably 100,000 mm2 or more. The upper limit of the projected area may be, for example, 300,000 mm2 or less. If the projected area of the formed article is too small, cracks are less likely to occur in the formed article, but it becomes difficult to use the formed article in certain applications such as turntables of semiconductor cleaning apparatuses for installing large wafers. In the formed article of the present disclosure, the projected area refers to the projected area of the formed article when viewed in the thickness direction of the formed article. The thickness of the formed article is 25 to 50 mm, preferably 47 mm or less, and more preferably 44 mm or less. If the formed article is too thick, it becomes difficult to reduce the degree of crystallinity of the formed article, and the article tends to develop cracks. If the formed article is too thin, cracks are less likely to occur in the formed article, but it becomes difficult to use the formed article in certain applications such as turntables of se