Vinylidene fluoride and trifluoroethylene containing polymers latexes

Patent metadata

Field	Value
Publication number	US-11629249-B2
Application number	US-201716340050-A
Country	US
Kind code	B2
Filing date	Sep 29, 2017
Priority date	Oct 5, 2016
Publication date	Apr 18, 2023
Grant date	Apr 18, 2023

Abstract

The invention provides novel latexes of particles of vinylidene fluoride/trifluoroethylene copolymers possessing a more ordered ferroelectric crystalline phase, and hence improved ferro-, pyro-, and piezo-electric properties, and a method for manufacturing the same by emulsion polymerization in the presence of certain cyclic fluorosurfactants.

First claim

The invention claimed is:

1. An aqueous latex comprising particles of a polymer (F), wherein polymer (F) comprises:
recurring units derived from vinylidene fluoride (VDF) in an amount of at least 60% moles and of at most 81% moles, with respect to the total moles of recurring units;
recurring units trifluoroethylene (TrFE) in an amount of at least 18% moles and of at most 39% moles, with respect to the total moles of recurring units, and
optionally recurring units derived from at least one additional monomer different from VDF and TrFE in an amount of 0 to 5% moles,
said polymer (F) possessing thermodynamic ordered structure in the ferroelectric phase, such that the relation between:
(i) the parameter Xc (%) defined as follows:

Xc
⁢

(
%
)

=

Δ
⁢

H
c

(

Δ
⁢

H
m

+

Δ
⁢

H
c

)

×
100

wherein ΔH c is the enthalpy associated to the Curie transition between ferroelectric and paraelectric phase, as determined in J/g by DSC technique on second heating scan, at a ramp rate of 10° C., and ΔH m , is the enthalpy of melting, as determined in J/g according to ASTM D3418; and
(ii) the content of recurring units different from VDF expressed in % moles, with respect to the total moles of recurring units, designated as CM (% moles), satisfies the following inequality: Xc (%)≥a·CM (% moles)+b wherein a=−1.10 and b=75.00; and
wherein the polymer (F) is obtained via polymerization in the presence of a fluorinated surfactant (C), wherein surfactant (C) complies with formula (I):

wherein X 1 , X 2 , X 3 , equal or different from each other are independently selected from H, F, and C 1-6 (per)fluoroalkyl groups, optionally comprising one or more catenary or non-catenary oxygen atoms; L represents a bond or a divalent group; R F is a divalent fluorinated C 1-3 bridging group; and Y is an anionic functionality.

2. The aqueous latex of claim 1 , wherein polymer (F) comprises recurring units derived from one or more than one fluoromonomers other than VDF and TrFE or recurring units derived from one or more than one non-fluorinated monomers.

3. The aqueous latex of claim 1 , wherein polymer (F) comprises:
recurring units trifluoroethylene (TrFE) in an amount of from 20% to 35% moles, with respect to the total moles of recurring units.

4. The aqueous latex of claim 1 , wherein polymer (F) consists essentially of recurring units derived from VDF and TrFE.

5. The aqueous latex of claim 1 , wherein the melt flow index (MFI) of polymer (F), as determined according to ASTM D 1238 (230° C./5 kg), is of 0.5 to 500 g/10 min.

6. The aqueous latex of claim 4 , wherein polymer (F) consists essentially of:
from 18 to 35% by moles of recurring units derived from TrFE; and
from 68 to 80% moles.

7. The aqueous latex of claim 5 , wherein the melt flow index (MFI) of polymer (F), as determined according to ASTM D 1238 (230° C./5 kg), is of 2 to 10 g/10 min.

Assignees

• Solvay Specialty Polymers It

Inventors

• Marrani Alessio
• Falco Ivan
• Kapelyushko Valeriy

Classifications

• H10D1/68

  Capacitors having no potential barriers · CPC title

• Y02P20/54

  using solvents, e.g. supercritical solvents or ionic liquids · CPC title

• C08F214/182

  Monomers containing fluorine not covered by the groups C08F214/20 - C08F214/28 · CPC title

• C08F214/22 Primary

  Vinylidene fluoride · CPC title

• H01G7/06

  having a dielectric selected for the variation of its permittivity with applied voltage, i.e. ferroelectric capacitors (electrets H01G7/02) · CPC title