Method for producing low molecular weight polytetrafluoroethylene, low molecular weight polytetrafluoroethylene, and powder
US-2019023856-A1 · Jan 24, 2019 · US
Method for producing composition containing low molecular weight polytetrafluoroethylene
US11548989B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-11548989-B2 |
| Application number | US-201916967799-A |
| Country | US |
| Kind code | B2 |
| Filing date | Feb 5, 2019 |
| Priority date | Feb 7, 2018 |
| Publication date | Jan 10, 2023 |
| Grant date | Jan 10, 2023 |
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Abstract
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A method for producing a composition containing low molecular weight polytetrafluoroethylene, the method including: (I) irradiating a composition containing high molecular weight polytetrafluoroethylene with ionizing radiation to obtain a composition containing low molecular weight polytetrafluoroethylene having a melt viscosity at 380° C. in the range of 1.0×102 to 7.0×105 Pa·s; and (II) decomposing a low molecular weight fluorine-containing compound contained in the composition containing low molecular weight polytetrafluoroethylene obtained above.
First claim
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The invention claimed is: 1. A method for producing a composition containing low molecular weight polytetrafluoroethylene, comprising: (I) irradiating a composition containing high molecular weight polytetrafluoroethylene with ionizing radiation to obtain a composition containing low molecular weight polytetrafluoroethylene having a melt viscosity at 380° C. in the range of 1.0×10 2 to 7.0×10 5 Pa·s; and (II) decomposing a low molecular weight fluorine-containing compound contained in the composition containing low molecular weight polytetrafluoroethylene obtained above by irradiation of ultraviolet light, wherein the high molecular weight polytetrafluoroethylene has a standard specific gravity in the range of 2.130 to 2.230, the composition containing high molecular weight polytetrafluoroethylene is at least one selected from the group of a molded body, a scrap, a fragment produced during formation of a molded body, a cutting chip produced during cutting of a molded body, and a preform; and the low molecular weight fluorine-containing compound is an acid having a fluorine-containing carbon chain having 6 to 14 carbon atoms or its derivative. 2. The method for producing a composition containing low molecular weight polytetrafluoroethylene according to claim 1 , wherein irradiation with ultraviolet light of 10 to 400 nm is carried out as the ultraviolet light irradiation. 3. The method for producing a composition containing low molecular weight polytetrafluoroethylene according to claim 1 , wherein the step (II) comprises decomposing a low molecular weight fluorine-containing compound and grinding the composition obtained in the step (I). 4. The method for producing a composition containing low molecular weight polytetrafluoroethylene according to claim 3 , wherein the step (II) comprises grinding the composition obtained in the step (I) and decomposing a low molecular weight fluorine-containing compound contained in the ground composition containing low molecular weight polytetrafluoroethylene. 5. The method for producing a composition containing low molecular weight polytetrafluoroethylene according to claim 1 , wherein a content of the low molecular weight fluorine-containing compound in the composition containing low molecular weight polytetrafluoroethylene obtained in the step (II) is 50 mass ppb or less based on the low molecular weight polytetrafluoroethylene. 6. The method for producing a composition containing low molecular weight polytetrafluoroethylene according to claim 1 , wherein the low molecular weight fluorine-containing compound in the composition containing low molecular weight polytetrafluoroethylene obtained in the step (II) contains perfluorooctanoic acid and a salt thereof; and a content of the perfluorooctanoic acid and a salt thereof is less than 25 mass ppb based on the low molecular weight polytetrafluoroethylene.
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- What does patent US11548989B2 cover?
- A method for producing a composition containing low molecular weight polytetrafluoroethylene, the method including: (I) irradiating a composition containing high molecular weight polytetrafluoroethylene with ionizing radiation to obtain a composition containing low molecular weight polytetrafluoroethylene having a melt viscosity at 380° C. in the range of 1.0×102 to 7.0×105 Pa·s; and (II) decom…
- Who is the assignee on this patent?
- Daikin Ind Ltd
- What technology area does this patent fall under?
- Primary CPC classification C08K5/095. Mapped technology areas include Chemistry & Metallurgy.
- When was this patent published?
- Publication date Tue Jan 10 2023 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
- What related patents are in patentsdb?
- We list 1 related publication on this page (citations in our corpus or others sharing the same primary CPC).