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Aqueous dispersion of low molecular weight polytetrafluorethylene and preparation method thereof

An aqueous dispersion, polytetrafluoroethylene technology, applied in the directions of pharmaceutical formulations, cosmetic preparations, cosmetic preparations, etc., can solve the problem of unrecorded data suggesting that the chain transfer agent is added to the polymer emulsion particle size and molecular weight, lack of practical issues of sex

Active Publication Date: 2012-05-30
DAIKIN IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] However, the polymer solid content concentration of the aqueous dispersion described in the examples of Patent Document 8 is as thin as 6.5% by weight, and it is very impractical in terms of productivity.
In addition, Patent Document 8 does not describe any data suggesting the addition of a chain transfer agent, the emulsified particle diameter and the molecular weight of the obtained polymer.

Method used

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  • Aqueous dispersion of low molecular weight polytetrafluorethylene and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] APFO is not added to the system, and the polymerization initiator and the chain transfer agent are the amounts shown in Table 1, and the stirring speed in the reaction is controlled to 700rpm, except that, in the same manner as in Comparative Example 1, an aqueous solution of low molecular weight PTFE was obtained. Dispersions. In the resulting aqueous dispersion, polymer particles hardly appeared on the air-liquid interface.

[0040] Coagulation, washing, and drying steps were performed on the above-mentioned aqueous dispersion in the same manner as in Comparative Example 1 to obtain the target low-molecular-weight PTFE powder.

[0041] Add TDS-80C (Daiichi Kogyo Pharmaceutical Co., Ltd.) at 6.0% by mass relative to the mass of low-molecular-weight PTFE as a nonionic surfactant to the above-mentioned aqueous dispersion, adjust the pH to 9.0 with aqueous ammonia, and place the mixture under normal pressure. By standing still at a temperature of 65° C., water was evapor...

Embodiment 2

[0043] An aqueous dispersion of low-molecular-weight PTFE was obtained in the same manner as in Example 1, except that the stirring speed during the reaction was controlled to 600 rpm. In the resulting aqueous dispersion, polymer particles hardly appeared on the air-liquid interface.

[0044] Coagulation, washing, and drying steps were performed on the aqueous dispersion in the same manner as in Example 1 to obtain the desired low-molecular-weight PTFE powder.

Embodiment 3

[0046] An aqueous dispersion of low-molecular-weight PTFE was obtained in the same manner as in Example 1, except that the stirring speed during the reaction was controlled to 500 rpm. In the resulting aqueous dispersion, polymer particles hardly appeared on the air-liquid interface. Coagulation, washing, and drying steps were performed on the aqueous dispersion in the same manner as in Example 1 to obtain a low-molecular-weight PTFE powder as the target object.

[0047] The aqueous dispersion of low-molecular-weight PTFE obtained in each embodiment and comparative example 1 was subjected to the physical property evaluations of the following (1) to (2), and the powder obtained in each embodiment and each comparative example was subjected to the following (3) )~(7) physical performance evaluation.

[0048] (1) Solid content concentration (P%) in aqueous dispersion

[0049] The aqueous dispersion (Xg) was heated at 150° C. for 3 hours, and the solid content concentration (P%) ...

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Abstract

The invention relates to a lowmolecular weight polytetrafluoroethylene dispersion liquid and a preparing method thereof, relates to a method for preparing lowmolecular weight polytetrafluoroethylene (PTEE) dispersion liquid with low cost and without adding fluorine-containing surfactant. In the method, without adding fluorine-containing surfactant, on the basis of a chain transfer agent, emulsionpolymerization of tetrafluorethylene (TFE) is carried out in aqueous medium containing a polymerization initiator or emulsion polymerization of monomers capable of copolymerizing with TFE and TFE. The method is characterized in that the chain transfer agent is a compound which is selected from at one of hydrocarbon having 1-3 H and C and halohydrocarbon having 1-3 C, the polymerization initiator is a water-soluble peroxide.

Description

technical field [0001] The invention relates to a low-molecular-weight polytetrafluoroethylene aqueous dispersion and a manufacturing method thereof. Background technique [0002] Low-molecular-weight polytetrafluoroethylene (PTFE) (also known as PTFE micropowder) with a molecular weight of less than 600,000 has excellent chemical stability, extremely low surface energy, and is difficult to fibrillate. Additives for the surface texture of coating films are used in the manufacture of plastics, inks, cosmetics, paints, greases, etc. (for example, see Patent Document 1). [0003] As a method for producing low-molecular-weight PTFE, the following methods are known: a method of thermally decomposing high-molecular-weight PTFE and a specific fluoride at a high temperature (for example, see Patent Document 2); Or a method of irradiating a molded body with ionizing radiation (for example, see Patent Document 3) and the like. [0004] The method of thermally decomposing high-molecu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F14/26C08F2/38C08F2/22C08F4/28C08J3/07C08J3/16C09D127/18C08L27/18A61K8/81C10M147/02G03G9/08
Inventor 辻雅之山中拓泽田又彦
Owner DAIKIN IND LTD