Sprayable powder of non-fibrillatable fluoropolymer

A fluoropolymer, non-fibrillation technology, which is applied in the treatment of dyed polymer organic compounds, powder coatings, fibrous fillers, etc., and can solve problems such as hindering direct recycling

Inactive Publication Date: 2002-04-17
THE CHEMOURS CO FC LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Separation in fly paint prevents direct recirculation to spray operations

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-8

[0072] Examples 1-8 Preparation of sprayable powders from aqueous dispersions

[0073] Sprayable powders were prepared by feeding aqueous dispersions of fluoropolymers and additional components as indicated into a spray dryer (shown in Figure 1 ) according to the 8 different compositions listed in Table 1 . For Examples 1-7, the spray dryer used was a Model 69 commercially available from APVA Americas, Inc., Tonawanda, NY. For Example 8, the spray dryer was also a laboratory model PSD-52 commercially available from APV. At the top of the chamber, the aqueous dispersion is passed through the centrifugal sprayer into the hot gas layer, where the dispersion is rapidly evaporated into primary particles which start to condense and dry during their descent through the chamber. The specific process conditions are listed in Table 1, including the air temperature at the chamber inlet and chamber outlet, the rotation speed of the atomizer and the air flow rate through the chamber. Pow...

Embodiment 8

[0082] *Example 8 APV laboratory dryer PSD-52 type, others are APV69 type.

[0083] Example 1

Example 2

Example 3

Powder category

PFA-1

PFA-2

PFA-3

Compression / densification process conditions

- roller pressure,

Psig(MPa)

1100(7.6)

650(4.5)

1000(6.9)

- degassed vacuum pressure, room temperature,

Hg column

15

12

15

- Sizing screen size, mils

156

125

200

Particle packing density

g / 100cc

98

96

101

[0084] Example 4

Example 5

Example 6

Example 7

Example 8

powder blend

50% PFA-3

+50% FEP-1

PFA-1+3%

TiO 2 (pigment)

PFA-1+8%

SiC (filler)

PFA-2+8%

Graphite (filler)

PFA-3+1%Sn

(stabilizer)

Compression / densification

Process conditions

- roller pressure,

Psig(MPa)

1200(8.3

)

650(4.5)

...

Embodiment 10

[0094] The TGA analysis of Example 10 did not reproduce the fully expected 8% by weight. Approximately 2% by weight of the inorganics was significantly volatile, consistent with all samples. This is unusual. Fluoropolymers decompose into highly reactive species such as hydrogen fluoride. Hydrogen fluoride is capable of reacting with inorganic substances, sometimes forming volatile fluorine-containing inorganic species.

[0095] Coatings on flat panels produced from the sprayable powder of Example 10 (ignoring the consistent 2% loss) contained substantially equal component concentrations of fluoropolymer and added components to the bulk sprayable powder. In this example, there was essentially no difference in the minor component concentration between the coating produced by spraying and the bulk sprayable powder of Example 10 relative to the minor component concentration of the sprayable bulk powder. The powder prepared by the method described in Example 10 was a homogeneous...

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Abstract

The invention provides for sprayable powder comprising friable granules of agglomerated primary particles of non-fibrillatable fluoropolymer and, optionally, at least one other component, the powder having a bulk density of at least 20g/100cc and average particle size of 5 to 100 micrometers. The sprayable powder is preferably free of water immiscible liquid, and more preferably free of halocarbon liquid. Included among the other components are inorganic fillers, pigments, high temperature resistant polymer binders. In an other embodiment, the invention provides for a sprayable powder comprising friable granules of agglomerated primary particles of a first non-fibrillatable fluoropolymer and at least one other non-fibrillatable component. The invention further provides for a process for preparing the sprayable powder by spray drying a liquid dispersion. In a preferred embodiment, the process includes densifying the granules of agglomerated primary particles that result from spray drying. Densifying may be carried out by mechanical compaction or by contacting the granules with a heated gas to form a fluidized bed. Optional steps of communication and heat treatment may be employed to achieve a desired bulk density and particle size for specific applications.

Description

field of invention [0001] This invention relates to non-fibrillated fluoropolymers, and more particularly to sprayable powders thereof. Background of the invention [0002] Fluoropolymer resins with properties such as good chemical resistance, excellent release properties, good heat resistance and electrical insulation are desirable in many applications. Melt flowable fluoropolymer powders have been found useful for coating cooking utensils such as frying pans, saucepans, rice steamers, grills and griddles as well as many industrial applications such as fuser rolls or belts for copiers and printers and chemical Handle the reactor. One of the advantages of applying powder coatings instead of liquid coatings is the absence of volatile organic solvents which involve environmental concerns and require costly remedial measures. [0003] Canadian Patent 1,248,292 (Buckmaster et al.) discloses a general process for the preparation of dry powders in which an aqueous polymeric disp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09D5/03B29B9/08C08J3/12C08K3/00C08L27/12C08L27/18C09C1/40C09C3/10C09D127/18
CPCB29B9/08C09D127/18C08L27/18C08J2327/12B29K2027/18C08J2327/18B29B2009/125C08J3/122C08L2205/02C08L2666/04C08J3/12
Inventor V·M·菲利克斯P·L·赫斯曼
Owner THE CHEMOURS CO FC LLC
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