U.S. patent application number 13/424881 was filed with the patent office on 2012-07-19 for copolymers for barriers.
This patent application is currently assigned to HONEYWELL INTERNATIONAL INC.. Invention is credited to NANCY IWAMOTO, TAO LI, ERIC J. RAINAL, GEORGE J. SAMUELS, GREGORY J. SHAFER, CLINTON A. THRELFALL.
Application Number | 20120184697 13/424881 |
Document ID | / |
Family ID | 39562935 |
Filed Date | 2012-07-19 |
United States Patent
Application |
20120184697 |
Kind Code |
A1 |
SAMUELS; GEORGE J. ; et
al. |
July 19, 2012 |
COPOLYMERS FOR BARRIERS
Abstract
A polyvinylidene difluoride copolymer with a fluoroolefin
selected from 2,3,3,3-tetrafluoropropene,
1,1,3,3,3-pentafluoropropene, 2-chloro-pentafluoropropene,
hexafluoropropylene, trifluoroethylene, chlorotrifluoroethylene,
3,3,3-trifluoro-2-trifluoromethylpropene and a mixture thereof,
wherein the stoichiometry of the co-monomers defines the barrier
properties of the copolymer. Such polymers include moisture barrier
copolymers and oxygen barrier copolymer. Processes for preparing
such moisture barrier copolymers and oxygen barrier copolymers are
also provided.
Inventors: |
SAMUELS; GEORGE J.;
(Williamsville, NY) ; SHAFER; GREGORY J.; (Newark,
DE) ; LI; TAO; (Parsippany, NJ) ; THRELFALL;
CLINTON A.; (Whorton, NJ) ; IWAMOTO; NANCY;
(Ramona, CA) ; RAINAL; ERIC J.; (Morristown,
NJ) |
Assignee: |
HONEYWELL INTERNATIONAL
INC.
MORRISTOWN
NJ
|
Family ID: |
39562935 |
Appl. No.: |
13/424881 |
Filed: |
March 20, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11961660 |
Dec 20, 2007 |
8163858 |
|
|
13424881 |
|
|
|
|
60871006 |
Dec 20, 2006 |
|
|
|
Current U.S.
Class: |
526/249 ;
526/250 |
Current CPC
Class: |
C08F 214/225 20130101;
C08F 214/18 20130101; C01B 5/00 20130101; C08J 5/18 20130101; C08J
2327/16 20130101; B60C 1/0008 20130101; Y02P 20/582 20151101; C01B
13/0255 20130101; C01B 2210/0062 20130101; C08F 214/22 20130101;
Y02E 60/32 20130101 |
Class at
Publication: |
526/249 ;
526/250 |
International
Class: |
C08F 214/22 20060101
C08F214/22 |
Claims
1.-11. (canceled)
12. A moisture barrier copolymer comprising: from about 0.1 wt % to
about 50 wt % vinylidene fluoride; and from about 50 wt % to about
99.9 wt % a fluorinated comonomer; wherein said copolymer is
substantially impermeable to moisture.
13. The moisture barrier copolymer of claim 12, wherein said
vinylidene fluoride is from about 5 wt % to about 30 wt % of the
copolymer; and wherein said fluorinated comonomer is from about 70
wt % to about 95 wt % of the copolymer.
14. The moisture barrier copolymer of claim 12, wherein said
vinylidene fluoride is from about 5 wt % to about 15 wt % of the
copolymer; and wherein said fluorinated comonomer is from about 85
wt % to about 95 wt % of the copolymer.
15. The moisture barrier copolymer of claim 12, wherein said
fluorinated comonomer is selected from the group consisting of:
2,3,3,3-tetrafluoropropene, 1,1,3,3,3-pentafluoropropene,
2-chloro-pentafluoropropene, hexafluoropropylene,
trifluoroethylene, chlorotrifluoroethylene,
3,3,3-trifluoro-2-trifluoromethylpropene and a mixture thereof.
16. The moisture barrier copolymer of claim 12, further comprising
a non-fluorinated comonomer.
17. The moisture barrier copolymer of claim 16, wherein said
non-fluorinated comonomer is selected from the group consisting of:
an alkene of 2-8 carbon atoms, acrylate or methacrylate ester of 4
to 24 carbon atoms, hydroxyethyl acrylate or methacrylate,
hydroxypropyl acrylate or methacrylate, glycidyl acrylate or
methacrylate, acrylonitrile, methacrylonitrile, vinyl ether of 4 to
24 carbon atoms optionally substituted by at least one hydroxy
group, styrene, alpha-methylstyrene, paramethyl styrene, allyl
alcohol, methallyl alcohol, vinyl acetate, vinyl carboxylate of
5-24 carbon atoms wherein the carboxylate is optionally substituted
by at least one hydroxy group, methyl ethyl ketone, hydroxyethyl
vinyl ether, hydroxybutyl vinyl ether, alkyl vinyl ether, and
combinations thereof.
18. A process for the preparation of a moisture barrier copolymer
of claim 12, comprising the step of contacting in a reaction zone:
vinylidene fluoride; a fluorinated comonomer; an initiator; and
optionally a non-fluorinated comonomer; wherein said contacting is
carried out at a temperature, pressure and length of time
sufficient to produce a moisture barrier copolymer having a
composition comprising from about 0.1 wt % to about 50 wt %
vinylidene fluoride; and from about 50 wt % to about 99.9 wt % a
fluorinated comonomer.
19. The process of claim 18, wherein said reaction zone further
comprises a solvent selected from the group consisting of: water,
ethyl acetate, butyl acetate, toluene, xylene, methyl ethyl ketone,
2-heptanone, 1-methoxy-2-propanol acetate, 1,1,1-trichloroethane
and mixtures thereof.
20. The process of claim 18, wherein said fluorinated comonomer is
selected from the group consisting of: 2,3,3,3-tetrafluoropropene,
1,1,3,3,3-pentafluoropropene, 2-chloro-pentafluoropropene,
hexafluoropropylene, trifluoroethylene, chlorotrifluoroethylene,
3,3,3-trifluoro-2-trifluoromethylpropene and a mixture thereof.
21. The process of claim 18, further comprising a non-fluorinated
comonomer.
22. The process of claim 18, wherein said non-fluorinated comonomer
is selected from the group consisting of: an alkene of 2-8 carbon
atoms, acrylate or methacrylate ester of 4 to 24 carbon atoms,
hydroxyethyl acrylate or methacrylate, hydroxypropyl acrylate or
methacrylate, glycidyl acrylate or methacrylate, acrylonitrile,
methacrylonitrile, vinyl ether of 4 to 24 carbon atoms optionally
substituted by at least one hydroxy group, styrene,
alpha-methylstyrene, paramethyl styrene, allyl alcohol, methallyl
alcohol, vinyl acetate, vinyl carboxylate of 5-24 carbon atoms
wherein the carboxylate is optionally substituted by at least one
hydroxy group, methyl ethyl ketone, hydroxyethyl vinyl ether,
hydroxybutyl vinyl ether, alkyl vinyl ether, and combinations
thereof.
23. A moisture barrier copolymer, comprising: from about 90 wt % to
about 99.9 wt % chlorotrifluoroethylene and from about 10 wt % to
about 0.1 wt % of a fluoromonomer selected from the group
consisting of CF.sub.3CF.dbd.CH.sub.2, CF.sub.3CF.dbd.CF.sub.2,
CF.sub.3CH.dbd.CF.sub.2, CF.sub.3CF.dbd.CFH,
cis-CF.sub.3CH.dbd.CFH, trans-CF.sub.3CH.dbd.CFH,
CF.sub.3CH.dbd.CH.sub.2, and combinations thereof based on the
total weight of the copolymer.
24. The copolymer of claim 23, wherein the chlorotrifluoroethylene
is present from about 93 wt % to about 99.9 wt %, wherein the
fluoromonomer is present from about 7 wt % to about 0.1 wt %.
25. The copolymer of claim 23, wherein the chlorotrifluoroethylene
is present from about 96 wt % to about 99.9 wt %, wherein the
fluoromonomer is present from about 4 wt % to about 0.1 wt %.
26. The copolymer of claim 23, wherein the moisture permeability is
about 0.25 gm-mil/(100 in.sup.2-day) or less.
27. The copolymer of claim 23, wherein the moisture permeability is
about 0.2 gm-mil/(100 in.sup.2-day) or less.
28. The copolymer of claim 23, wherein the moisture permeability is
about 0.1 to about 0.25 gm-mil/(100 in.sup.2-day) or less.
29. The copolymer of claim 23, wherein the fluoromonomer is
CF.sub.3CF.dbd.CH.sub.2.
30. The copolymer of claim 23, further comprising a different
fluorinated comonomer and/or a non-fluorinated comonomer.
31. The copolymer of claim 23, wherein the copolymer is in the form
of a film.
32. A moisture barrier copolymer, comprising: from about 90 wt % to
about 99.9 wt % chlorotrifluoroethylene and from about 10 wt % to
about 0.1 wt % of a fluoromonomer based on the total weight of the
copolymer, wherein the copolymer is substantially impermeable to
moisture.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional application of U.S.
patent application Ser. No. 11/961,660, filed Dec. 20, 2007,
(currently pending) which claims priority from U.S. Provisional
Patent Application No. 60/871,006, filed Dec. 20, 2006, the
contents each of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to the use of
polyvinylidene difluoride containing copolymers as barrier
materials wherein the gas diffusivity of the copolymer can be
controlled. More particularly, the present invention relates to
compositions where the composition of the copolymers defines the
barrier properties.
[0004] 2. Description of the Prior Art
[0005] Fluorine-containing monomers, polymers and copolymers are
described in U.S. Pat. Nos. 2,970,988, 2,931,840, 2996,555,
3,085,996, 6,486,281, 6,867,273 (see Column 3, line 29-50) and
6,703,450 (see Column 2, line 42, to Column 3, line 5, for
monomers). Vinylidene fluoride copolymers are described in U.S.
Pat. No. 3,893,987 and a process for making fluoroolefin copolymers
is described in U.S. Pat. No. 3,240,757. Vinylidene
fluoride/chlorotrifluoroethylene copolymers are described in U.S.
Pat. Nos. 5,292,816 and 3,053,818. Vinylidene
fluoride/3,3,3-trifluoro-2-trifluoromethylpropene copolymers and a
method for making vinylidene
fluoride/3,3,3-trifluoro-2trifluoromethylpropene copolymers are
described in U.S. Pat. No. 3,706,723.
[0006] Other copolymers made with fluoroolefins are described in
U.S. Pat. Nos. 2,599,640; 2,919,263; 3,812,066; 4,943,473;
5,200,480; 6,342,569 and 6,361,641.
[0007] Fluorocarbon/Acrylate Coatings are described in U.S. Pat.
No. 3,716,599 and powder coating are described in U.S. Pat. No.
5,030,394.
[0008] Solvent based blending is described in U.S. Pat. No.
3,324,069. Polyvinylidene fluoride/polymethyl methacrylate blends
are described in U.S. Pat. No. 6,362,271. Other blends are
described in U.S. Pat. Nos. 5,051,345; 5,496,889 (Compatibilized
Blends); 4,990,406 (F-terpolymer/acrylate blends). Graft Copolymers
are described in U.S. Pat. No. 4,308,359.
[0009] A wide variety of thermoplastic polymers are known, as are
films formed from such thermoplastic polymers. Important physical
characteristics of such films include their barrier properties,
including barriers to gas, aroma, and/or vapor such as water vapor,
as well as its physical characteristics, such as toughness, wear
and weathering resistances, and light transmittance. These
properties are especially important in film applications such as,
for example, in the use of films as a packaging material for food
or medical products.
[0010] It is well known in the art to produce multilayer
fluoropolymers films. See, for example, U.S. Pat. Nos. 4,146,521;
4,659,625; 4,677,017; 5,139,878; 5,855,977; 6,096,428; 6,138,830;
and 6,197,393. Many fluoropolymers materials are commonly known for
their excellent moisture and vapor barrier properties, and
therefore are desirable components of packaging films. In addition,
fluoropolymers exhibit high thermal stability and excellent
toughness.
[0011] Polychlorotrifluoroethylene has been employed as a high
performance moisture bather polymer. Comonomers, such as vinylidene
fluoride, have been introduced to modify water permeation rate or
other physical properties (WO 9306159 and U.S. Published
Application No. 2007128393). Various fluorocopolymers, including
copolymers of 2,3,3,3-tetrafluoro-1-propene and
chlorotrifluoroethylene, were disclosed in U.S. Pat. No. 2,970,988
as useful in protective coatings and as elastomers.
[0012] There is a continuing need in the art for further
improvements in to fluoropolymers films and film structures,
particularly those which provide a film structure featuring
differentiated barrier performance for different gases and/or water
vapor. This invention provides compositions showing specific
controlled gas diffusivity for oxygen and for water vapor as
defined by copolymer stoichiometry.
[0013] For this reason, the copolymer compositions and the
processes for making these compositions according to the present
invention are potentially useful commercially.
SUMMARY OF THE INVENTION
[0014] The present invention provides an oxygen barrier copolymer.
The oxygen barrier copolymer includes:
[0015] from about 50 wt % to about 99.9 wt % vinylidene fluoride;
and
[0016] from about 0.1 wt % to about 50 wt % a fluorinated
comonomer;
[0017] wherein said copolymer is substantially impermeable to
oxygen.
[0018] The present invention also provides a moisture or water
vapor bather copolymer. The moisture barrier copolymer
includes:
[0019] from about 0.1 wt % to about 50 wt % vinylidene fluoride;
and
[0020] from about 50 wt % to about 99.9 wt % a fluorinated
comonomer;
[0021] wherein said copolymer is substantially impermeable to
moisture.
[0022] The present invention further provides a process for the
preparation of an oxygen barrier copolymer. The process includes
the step of contacting in a reaction zone:
[0023] vinylidene fluoride;
[0024] a fluorinated comonomer;
[0025] an initiator; and optionally
[0026] a non-fluorinated comonomer;
[0027] wherein said contacting is carried out at a temperature,
pressure and length of time sufficient to produce an oxygen barrier
copolymer having a composition including from about 50 wt % to
about 99.9 wt % vinylidene fluoride and from about 0.1 wt % to
about 50 wt % a fluorinated comonomer.
[0028] The present invention further provides a process for the
preparation of a moisture barrier copolymer. The process includes
the step of contacting in a reaction zone:
[0029] vinylidene fluoride;
[0030] a fluorinated comonomer;
[0031] an initiator; and optionally
[0032] a non-fluorinated comonomer;
[0033] wherein said contacting is carried out at a temperature,
pressure and length of time sufficient to produce a moisture
barrier copolymer having a composition including from about 0.1 wt
% to about 50 wt % vinylidene fluoride; and from about 50 wt % to
about 99.9 wt % a fluorinated comonomer.
[0034] There is also provided another embodiment of a moisture
and/or gas bather copolymer. The copolymer has from about 90 wt %
to about 99.9 wt % chlorotrifluoroethylene and from about 10 wt %
to about 0.1 wt % of a fluoromonomer. The copolymer can be selected
from the group consisting of 2,3,3,3-tetrafluoro-1-propene,
CF.sub.3CF.dbd.CF.sub.2, CF.sub.3CH.dbd.CF.sub.2,
CF.sub.3CF.dbd.CFH, cis-CF.sub.3CH.dbd.CFH,
trans-CF.sub.3CH.dbd.CFH, CF.sub.3CH.dbd.CH.sub.2, and combinations
thereof based on the total weight of the copolymer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 is a chart showing a comparison of oxygen diffusion
into two copolymers; one a 10:1 vinylidene fluoride:
2,3,3,3-tetrafluoropropene random copolymer composition and the
other a 1:10 vinylidene fluoride: 2,3,3,3-tetrafluoropropene random
copolymer composition.
[0036] FIG. 2 is a chart showing water diffusion into a copolymer
of 10:1 vinylidene fluoride: 2,3,3,3-tetrafluoropropene random
copolymer composition.
[0037] FIG. 3 is a chart showing water diffusion into a copolymer
of a 1:10 vinylidene fluoride: 2,3,3,3-tetrafluoropropene random
copolymer composition.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] The present invention relates to fluoroolefin copolymers
with specific barrier properties and the process for making
them.
[0039] The oxygen bather copolymer present invention includes from
about 50 wt % to about 99.9 wt % vinylidene fluoride and from about
0.1 wt % to about 50 wt % a fluorinated comonomer.
[0040] In contrast, the moisture or water vapor barrier copolymer
includes from about 0.1 wt % to about 50 wt % vinylidene fluoride
and from about 50 wt % to about 99.9 wt % a fluorinated
comonomer.
[0041] Fluorinated comonomer selected from
2,3,3,3-tetrafluoropropene, 1,1,3,3,3-pentafluoropropene,
2-chloro-pentafluoropropene, hexafluoropropylene,
trifluoroethylene, chlorotrifluoroethylene,
3,3,3-trifluoro-2-trifluoromethylpropene, and a mixture thereof,
are preferred.
[0042] However, other fluorinated comonomers and non-fluorinated
comonomers may also be used in modest amounts.
[0043] Such fluorinated comonomers include a fluoroolefin comonomer
represented by the formula:
R.sup.1R.sup.2C.dbd.CR.sup.3R.sup.4
[0044] wherein each of R.sup.1, R.sup.2, R.sup.3, and R.sup.4 is
independently selected from hydrogen, chloro, fluoro, hydroxy,
alkoxy, alkoxycarbonyl, acyl, cyano, linear, branched or cyclic
alkyl of 1-6 carbon atoms optionally substituted by at least one
fluorine, aryl of 1-6 carbon atoms optionally substituted by at
least one fluorine, with the proviso that at least one of the
R.sup.1, R.sup.2, R.sup.3, and R.sup.4 groups is either fluorine or
a fluorine-containing group, and a mixture thereof. Examples of the
fluoroolefin comonomer include CFH.dbd.CH.sub.2,
CF.sub.2.dbd.CH.sub.2, CF.sub.2.dbd.CFH, CF.sub.2.dbd.CF.sub.2,
CClF.dbd.CF.sub.2, CBrF.dbd.CF.sub.2, CF.sub.3CH.dbd.CHF,
CF.sub.3CF.dbd.CF.sub.2, CF.sub.3CH.dbd.CF.sub.2,
cis-CF.sub.3CF.dbd.CHF, trans-CF.sub.3CF.dbd.CHF,
CF.sub.3CH.dbd.CH.sub.2, CF.sub.3CF.dbd.CH.sub.2,
CF.sub.3CF.sub.2CF.dbd.CF.sub.2, CF.sub.3CF.sub.2CH.dbd.CF.sub.2,
CF.sub.3CF.sub.2CF.dbd.CHF, CF.sub.3CF.sub.2CH.dbd.CH.sub.2,
CF.sub.3CF.sub.2CF.dbd.CH.sub.2,
CF.sub.3CF.sub.2CF.sub.2CF.dbd.CF.sub.2,
CF.sub.3CF.sub.2CF.sub.2CH.dbd.CF.sub.2,
CF.sub.3CF.sub.2CF.sub.2CF.dbd.CHF,
CF.sub.3CF.sub.2CF.sub.2CH.dbd.CH.sub.2,
CF.sub.3CF.sub.2CF.sub.2CF.dbd.CH.sub.2, CF.sub.3CH.dbd.CHCF.sub.3,
CF.sub.3CH.dbd.CFCF.sub.3, CF.sub.3CF.dbd.CFCF.sub.3,
HOCH.sub.2CH.dbd.CHF, HOCH.sub.2CH.dbd.CF.sub.2,
HOCH.sub.2CF.dbd.CH.sub.2, HOCH.sub.2CF.dbd.CHF,
HOCH.sub.2CF.dbd.CF.sub.2, HOCH.sub.2CF.dbd.CH.sub.2,
CF.sub.3CH.dbd.CHCl, CF.sub.3CCl.dbd.CH.sub.2, CF.sub.3CCl.dbd.CHF,
CF.sub.3CCl.dbd.CF.sub.2, CF.sub.3CF.dbd.CHCl, CF.sub.3CH.dbd.CFCl,
(CF.sub.3).sub.2C.dbd.CH.sub.2,
CF.sub.3CF.sub.2CF.sub.2CF.sub.2CH.dbd.CH.sub.2,
CF.sub.3CF.sub.2CF.sub.2OCF.dbd.CF.sub.2,
CF.sub.3CF.sub.2CF.sub.2CF.sub.2CH.dbd.CH.sub.2, and mixtures
thereof.
[0045] Additional examples of fluorinated comonomers include
.alpha.-trifluoromethylacrylate, .alpha.-trifluoromethylacrylate,
.alpha.-trifluoromethylacrylate, vinyl ether of 4 to 24 carbon
atoms substituted by at least one fluorine atoms, vinyl carboxylate
of 5-24 carbon atoms wherein the carboxylate is substituted by at
least one fluorine, and perfluoroalkyl vinyl ether.
[0046] Examples of such non-fluorinated comonomers include alkene
of 2-8 carbon atoms, acrylate or methacrylate ester of 4 to 24
carbon atoms, hydroxyethyl acrylate or methacrylate, hydroxypropyl
acrylate or methacrylate, glycidyl acrylate or methacrylate,
acrylonitrile, methacrylonitrile, vinyl ether of 4 to 24 carbon
atoms optionally substituted by at least one hydroxy group,
styrene, alpha-methylstyrene, paramethyl styrene, allyl alcohol,
methallyl alcohol, vinyl acetate, vinyl carboxylate of 5-24 carbon
atoms wherein the carboxylate is optionally substituted by at least
one hydroxy group, methyl ethyl ketone, hydroxyethyl vinyl ether,
hydroxybutyl vinyl ether, alkyl vinyl ether, and combinations
thereof,
[0047] Specific examples of the non-fluorinated comonomers include
alkene of 2-8 carbon atoms, acrylate or methacrylate ester of 4 to
24 carbon atoms, acrylonitrile, methacrylonitrile, vinyl ether,
styrene, alpha-methylstyrene, paramethyl styrene, allyl alcohol,
methallyl alcohol, vinyl acetate, vinyl carboxylate of 5-24 carbon
atoms, methyl ethyl ketone, hydroxyethyl vinyl ether, hydroxybutyl
vinyl ether, alkyl vinyl ether, and a mixture thereof and examples
of the acrylic non-fluorinated comonomers include methyl acrylate,
ethyl acrylate, propyl acrylate, butyl acrylate,
ethylhexylacrylate, octyl acrylate, dodecyl acrylate, stearyl
acrylate, benzyl acrylate, phenyl acrylate, methylmethacrylate,
ethylmethacrylate, butylmethacrylate, ethylhexymethacrylate, and
combinations to thereof.
[0048] To achieve an oxygen bather copolymer including monomers
vinylidene fluoride and a second fluorinated olefin, the weight
percentage of vinylidene fluoride is at least 50% and no more than
99.9% and the weight percentage of the second fluoroolefin is at
least 0.1% and no more than 50%. Said compositions differentiate
between diffusivities of oxygen and, for example, water vapor
providing superior barrier properties toward oxygen as compared
with bather properties toward water vapor.
[0049] To achieve a moisture barrier copolymer including monomers
vinylidene fluoride and a second fluorinated olefin, the weight
percentage of vinylidene fluoride is at least 0.1% and no more than
50% and the weight percentage of the second fluoroolefin is at
least 50% and no more than 99.9%. Said compositions differentiate
between diffusivities of water vapor and, for example, oxygen
providing superior barrier properties toward water vapor as
compared with barrier properties toward oxygen.
[0050] It has been found that the diffusion properties of
vinylidene fluoride/fluoroolefin copolymers are different for
oxygen and moisture depending on the copolymer composition. Thus
the vinylidene fluoride/fluoroolefin copolymer can act as a
differential barrier between oxygen and moisture. Materials
including films may be manufactured showing specific barrier
properties. Films with different stoichiometries may be bonded
together for combined effects.
[0051] When a random copolymer of vinylidene
fluoride/2,3,3,3-tetrafluoropropene with a high proportion of
vinylidene fluoride, the material has a low bather to water but a
higher barrier to oxygen. When the monomer proportions are reversed
the diffusivity trends are reversed. This means that gas
diffusivity can be controlled through the stoichiometric
composition of the vinylidene fluoride/fluoroolefin copolymer.
[0052] Without being limited by theory, the diffusivity differences
appear to be related to interaction differences of the gases with
the polymer composition.
[0053] As can be seen in FIG. 1, the invention provides vinylidene
fluoride/fluoroolefin copolymer compositions wherein the higher the
vinylidene fluoride content in the copolymer composition the higher
the bather to oxygen diffusion. Thus polyvinylidene fluoride has
excellent bather properties toward oxygen and these properties are
maintained in the copolymer composition of 10:1 vinylidene
fluoride: 2,3,3,3-tetrafluoropropene.
[0054] As can be seen in FIG. 2, the invention provides vinylidene
fluoride/fluoroolefin copolymer compositions wherein the higher the
vinylidene fluoride content in the copolymer composition the lower
the bather to moisture diffusion. Thus high vinylidene fluoride
content vinylidene fluoride: 2,3,3,3-tetrafluoropropene copolymers
surprisingly demonstrate barrier properties toward moisture that
show a measurable and reverse interaction difference as compared
with bather properties shown toward oxygen diffusion.
[0055] Fluorine-containing polymers and copolymers are described in
U.S. Pat. Nos. 2,970,988 and 6,077,609. Vinylidene fluoride
copolymers are described in U.S. Pat. No. 3,893,987 and a process
for making fluoroolefin copolymers is described in U.S. Pat. No.
3,240,757. Vinylidene difluoride/chlorotrifluoroethylene copolymers
are described in U.S. Pat. Nos. 5,292,816 and 3,053,818. Vinylidene
fluoride/3,3,3-trifluoro-2-trifluoromethylpropene copolymers and a
method for making vinylidene
fluoride/3,3,3-trifluoro-2trifluoromethylpropene copolymers are
described in U.S. Pat. No. 3,706,723.
[0056] The fluoroolefin comonomer of the vinylidene
fluoride/fluoroolefin copolymer can be any fluoroolefin of suitable
reactivity that gives a copolymer with specific barrier properties.
In one preferred embodiment of the invention the second
fluoroolefin comonomer is selected from 2,3,3,3-tetrafluoropropene,
1,1,3,3,3-pentafluorpropene and 2-chloro-pentafluoropropene. In a
more preferred embodiment of the invention the second fluoroolefin
comonomer is 2,3,3,3-tetrafluoropropene. In yet another more
preferred embodiment of the invention the second fluoroolefin
comonomer is 1,1,3,3,3-pentafluoropropene.
[0057] In another preferred embodiment of the invention the second
fluoroolefin comonomer is selected from hexafluoropropene,
trifluoroethylene, chlorotrifluoroethylene and
3,3,3-trifluoro-2-trifluoromethylpropene.
[0058] The oxygen barrier vinylidene fluoride/fluoroolefin
copolymer of the invention includes the weight percentage of the
vinylidene fluoride comonomer between 50 and 99.9% and the weight
percentage of the second fluoroolefin comonomer between 0.1 and
50%. In a preferred embodiment of the invention the weight
percentage of the vinylidene fluoride comonomer in the copolymer is
between 70 and 95% and the weight percentage of the second
fluoroolefin commoner in the copolymer is between 5 and 30%. In a
further preferred embodiment of the invention, the weight
percentage of the vinylidene fluoride comonomer in the copolymer is
between 85 and 95% and the weight percentage of the second
fluoroolefin comonomer in the copolymer is between 5 and 15%.
[0059] The moisture barrier vinylidene fluoride/fluoroolefin
copolymer of the invention includes the weight percentage of the
vinylidene fluoride comonomer between 0.1 and 50% and the weight
percentage of the second fluoroolefin comonomer between 50 and
99.9%. In a preferred embodiment of the invention the weight
percentage of the vinylidene fluoride comonomer in the copolymer is
between 5 and 30% and the weight percentage of the second
fluoroolefin commoner in the copolymer is between 70 and 95%. In a
further preferred embodiment of the invention, the weight
percentage of the vinylidene fluoride comonomer in the copolymer is
between 5 and 15% and the weight percentage of the second
fluoroolefin commoner in the copolymer is between 85 and 95%.
[0060] The invention still further provides a process for forming
the controlled bather vinylidene fluoride/fluoroolefin copolymers
of the invention including the step of contacting in a reaction
zone 1,1,-difluoroethylene; a fluorinated comonomer; an initiator;
and optionally a non-fluorinated comonomer; in a ratio such that
the desired copolymer composition designed for a specific use is
achieved.
[0061] Preferably, the contacting is carried out at a temperature,
pressure and length of time sufficient to produce said fluoroolefin
copolymer.
[0062] The invention still further provides said process wherein
said reaction zone preferably includes a solvent selective from
water, ethyl acetate, butyl acetate, toluene, xylene, methyl ethyl
ketone, 2-heptanone, 1-methoxy-2-propanol acetate,
1,1,1,-trichloroethane and mixtures thereof. A preferred solvent in
the reaction zone is water.
[0063] Another aspect of the process of the invention is use of
selected free-radical initiators. Common initiators used for free
radical polymerization of unsaturated monomers are generally
satisfactory in the process of the invention depending on the
nature and properties desired. For example, azo-type initiators
result in high polydispersity in the molecular weight distribution
whereas perester type peroxides produce a narrow molecular weight
distribution and, as such, are preferably used in most cases.
[0064] Examples of the initiator include azobiscyanoacrylates,
aliphatic peresters, such as, t-butyl peroctoate and t-amyl
peroctoate, aliphatic peroxides, such as, tert-butyl peroxide,
aliphatic hydroperoxides, such as, tert-butyl hydroperoxide,
inorganic peroxides such as sodium peroxide, inorganic persulfates
such as to potassium persulfate, redox initiators involving
persulfates as oxidant and sufites such as sodium metabisulfite as
reductant, percarbonates such as
t-butylperoxide-2-ethylhexylcarbonate, peroxydicarbonates,
perhaloacetyl peroxides and a mixture thereof.
[0065] Generally, the perester initiator is used at a concentration
of less than 20 weight percent based on the weight of the total
monomers, usually the perester initiator is used at concentrations
less than 12 weight percent, with a range of from 0.1 to 1.0 weight
percent being preferred.
[0066] Preferably, the perester initiator is added to the reaction
zone together with the monomeric reactants, i.e., the azeotropic
mixture of monomers, as previously stated. However, a minor amount
of peroxide as a finishing step may be added after the
polymerization reaction has substantially ended. Such a finishing
step has the purpose of removing minor amounts of unreacted
monomers and aids in achieving a reaction zone product that may be
used directly for the desired end use or application.
[0067] Thus, it is important that at least 50, and preferably at
least 80, weight percent of the peroxide to be added with the
monomers and the balance of the initiator added during the
polymerization reaction.
[0068] The polymerization process may be conducted in the presence
of tertiary amine or a tertiary mercaptan-type chain transfer
agent. The use a chain transfer agent may result in a copolymer of
suitable molecular weight to have the required organic solvent
solubility.
[0069] Generally, the chain transfer agent is used at a
concentration of less than 5 weight percent based on the weight of
monomers added to the reaction zone.
[0070] The process can be carried out as a continuous, batch, vapor
phase, fixed bed, solution, emulsion, or a suspension type of a
polymerization process.
[0071] The reaction zone can further include a diluent, such as, a
solvent or mixture of solvents. Solvents used in non-aqueous
polymerization methods are preferably, non-polar, non-reactive,
non-polymerizable, non-protic solvents are used as the reaction
medium. However, other solvents, such as, non-interfering
non-polymerizable liquid which is a solvent both for the monomers
and copolymer products of the invention. Suitable reaction solvents
include esters, ketones, ethers, aromatic hydrocarbons, chlorinated
hydrocarbons, aliphatic hydrocarbons, and mixtures thereof.
Illustrative solvents are ethyl acetate, butylacetate, toluene,
xylene, methyl ethyl ketone, 2-heptanone, and
1,1,1-tri-chloroethane. Mixtures thereof can also be employed. The
aqueous polymerization reaction is preferably conducted using water
soluble initiators, buffers such as inorganic phosphates or
carbonates to maintain required pH level, required emulsifiers such
as salts of perfluoroalkyl carbonates or sulfonates.
[0072] In operation, preferably at least 10 wt % of the reactants
are converted to the product. More preferably, up to at least 80 wt
% of the reactants are converted to the product, and most
preferably, at least 90 wt % of the reactants are converted to the
product.
[0073] Operation of the process of the present invention under high
conversion conditions is generally preferred, particularly under
batch or solution, emulsion or suspension conditions. However, for
continuous, vapor phase, or fixed bed reactions, the present
process provides the unique advantage of recycling of the unreacted
starting materials thereby providing a cost advantage over other
known processes of the prior art.
[0074] Polymerization can be carried out essentially the same way
as the methods known and described in the art, such as, the methods
described in J. Polymer Sci. A: Polym. Chem. (1997) 35, 1593-1604,
and in U.S. Pat. Nos. 2,970,988; 3,893,987 (see Example 2);
3,240,757; 5,292,816; 3,053,818 (see Example 6); 3,812,066;
2,599,640; 6,342,569; 5,200,480; and 2,919,263.
[0075] The reaction zone preferably has provision for agitation and
heat exchange to assist uniformity and process control.
[0076] The process can be carried out as a continuous, batch, vapor
phase, fixed bed, solution, emulsion, or a suspension type of a
polymerization process.
[0077] The reaction zone can further include a diluent, such as, a
solvent or mixture of solvents. Suitable reaction solvents include
water or non-polymerizable organic solvents including
perfluorinated and perchlorinated alkanes that are liquids at
20.degree. C. Other suitable reaction solvents include esters,
ketones, ethers, aromatic hydrocarbons, chlorinated hydrocarbons,
aliphatic hydrocarbons, and mixtures thereof. Illustrative solvents
are 1,1,1-trichloroethane, ethyl acetate, butyl acetate, toluene,
xylene, methyl ethyl ketone, and 2-heptanone. Mixtures thereof can
also be employed.
[0078] There is another embodiment of a moisture barrier copolymer
in the present invention. The copolymer affords a high degree of
resistance to moisture and gas permeation while exhibiting
desirable thermal properties. The copolymer has from about 90 wt %
to about 99.9 wt % CTFE (chlorotrifluoroethylene) monomer and from
about 10 wt % to about 0.1 wt % of a fluoromonomer. The
fluoromonomer is preferably selected from the group consisting of
2,3,3,3-tetrafluoro-1-propene, CF.sub.3CF.dbd.CF.sub.2,
CF.sub.3CH.dbd.CF.sub.2, CF.sub.3CF.dbd.CFH,
cis-CF.sub.3CH.dbd.CFH, trans-CF.sub.3CH.dbd.CFH,
CF.sub.3CH.dbd.CH.sub.2, and combinations thereof based on the
total weight of the copolymer. A copolymer of CTFE and 1234yf
(2,3,3,3-tetrafluoro-1-propene) is preferred. The copolymer
preferably has chlorotrifluoroethylene from about 93 wt % to about
99.9 wt % and the fluoromonomer from about 7 wt % to about 0.1 wt
%. The copolymer preferably has chlorotrifluoroethylene from about
96 wt % to about 99.9 wt % and the fluoromonomer from about 4 wt %
to about 0.1 wt %. The copolymer exhibits a moisture permeability
is about 0.25 gm-mil/(100 in.sup.2-day) or less, preferably about
0.2 gm-mil/(100 in.sup.2-day) or less. A permeability range of
about 0.1 gm-mil/(100 in.sup.2-day) to about 0.25 gm-mil/(100
in.sup.2-day) or less. The copolymer may also have comonomers of
other fluorinated monomers and/or non-fluorinated comonomers
therein, such as those described above.
[0079] Films may be manufactured using the bather copolymers
according to the present invention which show specific barrier
properties. In addition, a plurality of films of these copolymers
having different compositions may be bonded together for producing
multi-layered films that have the combined effects of the barrier
properties of the individual films.
[0080] The following non-limiting examples are illustrative of the
various embodiments of the present invention. It is within the
ability of a person of ordinary skill in the art to select other
variable from amongst the many known in the art without departing
from the scope of the present invention. Accordingly, these
examples shall serve to further illustrate the present invention,
not to limit them.
EXAMPLES
Example 1
Emulsion Copolymerization of 1234yf and VDF
[0081] A typical polymerization is run in a stirred stainless steel
autoclave in which reactants are added by methods known in the art.
To a 30 mL autoclave is added
(NH.sub.4).sub.2S.sub.2O.sub.8-ammonium persulfate: 0.14 g
dissolved in 1.0 mL of de-O.sub.2/DI water
Na.sub.2S.sub.2O.sub.5-sodium metasulfite: 0.3 g dissolved in 1.0
mL of de-O.sub.2/DI water. FeSO.sub.4-ferrous sulfate: 0.005 g
dissolved buffer solution. Na.sub.2HPO.sub.4/NaH.sub.2PO.sub.4
buffer: 1.34/0.68 g dissolved in 180 mL.
C.sub.7F.sub.15CO.sub.2(NH.sub.4) surfactant: 2.44 g dissolved with
buffer. Add 18 mL of the emulsion solution
(water/Na.sub.2HPO.sub.4/NaH.sub.2PO.sub.4/FeSO.sub.4/C.sub.7F.sub.15CO.s-
ub.2(NH.sub.4)).
[0082] During the polymerization, a mixture of the solution is
stirred while 9.5 g of a mixture of 10 mol % 1234yf and 90 mol % of
VDF are added in which an autogenous pressure is obtained at
10.degree. C. The pressure is kept during the polymerization to
obtain a constant concentration of monomer. After 48 hours, the
polymerization is stopped and monomers are released from the
autoclave. The polymerization latex was coagulated in 25% HCl and
polymer was washed and dried. 2.3 grams of a white copolymer was
obtained.
[0083] The copolymer of this example was tested for O.sub.2
diffusion. The results are shown in FIG. 1. The copolymer was also
tested for water permeation. The results are shown in FIG. 3. The
general penetration trends for water were opposite that of O.sub.2
and the 1234yf helped to block water.
[0084] An analogous copolymer having 90 mol % 1234yf and 10 mol %
of VDF was prepared in like manner as the above copolymer. The
analogous copolymer was tested for O.sub.2 diffusion. The results
are shown in FIG. 1. The analogous copolymer was also tested for
water permeation. The results are shown in FIG. 2.
Example 2
Emulsion Type Terpolymerization of VDF/CH2=CFCF3/CF2=CFCl
[0085] A typical polymerization is run in a stirred stainless steel
autoclave in which reactants are added by methods known in the art.
To a 300 mL autoclave is added
(NH.sub.4).sub.2S.sub.2O.sub.8-ammonium persulfate: 22 mL of a
solution of 1.12 g dissolved in 40 mL of de-O.sub.2/DI water.
Na.sub.2S.sub.2O.sub.5-sodium metasulfite: 12.5 mL of a solution of
2.4 g dissolved in 40 mL of de-O.sub.2/DI water. FeSO.sub.4-ferrous
sulfate: 0.005 g dissolved buffer solution.
Na.sub.2HPO.sub.4/NaH.sub.2PO.sub.4 buffer: 1.34/0.68 g dissolved
180 mL. C.sub.7F.sub.15CO.sub.2(NH.sub.4) surfactant: 2.44 g
dissolved with buffer. Add 180 mL of the emulsion solution
(water/Na.sub.2HPO.sub.4/NaH.sub.2PO.sub.4/FeSO.sub.4/C.sub.7F.s-
ub.15CO.sub.2(NH.sub.4)).
[0086] During the polymerization, a mixture of the solution is
stirred while 62.4 g of a mixture of 10.1 mol % 1234yf and 88.1 mol
% of CTFE and 1.8 mol % VDF are added and an autogenous pressure is
obtained at 10.degree. C. The pressure is kept during the
polymerization to obtain a constant concentration of monomer. After
6 hours, the polymerization is stopped and monomers are released
from the autoclave. The polymerization latex was coagulated in 25%
HCl and polymer was washed and dried. 26 grams of a white
terpolymer was obtained.
Example 3
Chlorotrifluoroethylene/1234yf Copolymer and Moisture Permeation
Comparison with Other Chlorotrifluoroethylene Polymers
CTFE/1234yf Copolymer Emulsion Polymerization
[0087] The deionized water was purged with nitrogen and the 300 ml
reactor was evacuated. The polymerization initiator solutions were
prepared by weighing out solids individually and completely
dissolving the solids separately in water just prior to use:
(NH.sub.4).sub.2S.sub.2O.sub.8-ammonium persulfate: 0.3 g dissolved
in 10 ml of deoxygenated de-ionized water,
Na.sub.2S.sub.2O.sub.5-sodium metasulfite: 4.5 g dissolved in 40 ml
of deoxygenated de-ionized water, FeSO.sub.4-ferrous sulfate: 0.005
g dissolved in the buffer solution,
Na.sub.2HPO.sub.4/NaH.sub.2PO.sub.4 buffer: 1.34/0.68 g
respectively is dissolved in 180 ml deoxygenated de-ionized water.
C.sub.7F.sub.15CO.sub.2(NH.sub.4) surfactant: 2.44 g dissolved with
buffer. Keep the reaction mixture temperature at about 10.degree.
C. Add 180 ml of the emulsion solution
(water/Na.sub.2HPO.sub.4/NaH.sub.2PO.sub.4/FeSO.sub.4/C.sub.7F.sub.15CO.s-
ub.2(NH.sub.4)) and pump into the autoclave via syringe. Add the
(NH.sub.4).sub.2S.sub.2O.sub.8 and Na.sub.2S.sub.2O.sub.5 solution
to the autoclave via syringe for initial charge (and then by
metering pump for future charges) and stir mixture. Fill an ISCO
syringe pump with CTFE/1234yf at a 95:5 mole percent ratio, 52.25
grams and 2.75 grams respectively. Start adding the CTFE/1234yf
solution rapidly to a system pressure of about 70 psig and continue
at constant flow of 100 ml/min until all the CTFE/1234yf has been
added. Let the reaction continue and make adjustments as necessary.
Let the reaction proceed to the desired level of completion by
monitoring system pressure.
CTFE-1234yf Copolymer Suspension Polymerization
[0088] A copolymer having 3 wt % 1234yf
(2,3,3,3-tetrafluoropropene) and 97 wt % CTFE
(chlorotetrafluoroethylene) was prepared as follows. Deionized
water was purged with nitrogen and the system evacuated. The
polymerization initiator solutions were prepared by weighing out
solids individually and completely dissolving the solids separately
in water just prior to use: (NH.sub.4).sub.252O.sub.8-ammonium
persulfate: 2.5 g dissolved in 40 ml of deoxygenated de-ionized
water, Na.sub.2S.sub.2O.sub.5-sodium metasulfite: 4.5 g dissolved
in 40 ml of deoxygenated de-ionized water, CuCl.sub.2-cupric
chloride: 0.01 g dissolved in the buffer buffer solution,
Na.sub.2HPO.sub.4/NaH.sub.2PO.sub.4 buffer: 3/1.5 g respectively is
dissolved in 400 ml of deoxygenated de-ionized water. Add 200 ml of
the water/Na.sub.2HPO.sub.4/NaH.sub.2PO.sub.4/CuCl solution and
pump into the 500 ml autoclave via metering pump or syringe. Add 15
mL Na.sub.2S.sub.2O.sub.5 solution to the autoclave via metering
pump and stir mixture. Keep the reaction mixture temperature at
20-21.degree. C. Add 15 ml of the (NH.sub.4).sub.252O.sub.8
solution to the autoclave via metering pump and stir mixture slowly
during the addition of monomer. Fill an ISCO syringe pump with
CTFE/1234yf at a 95:5 mole percent ratio at -35.degree. C. Monomer
is typical added at about 15% by weight of the water used in the
system. Start adding the 30 grams of CTFE/1234yf solution rapidly
to a system pressure of pressure to 100 psig and continue at
constant flow of 100 ml/min until all the CTFE/1234yf has been
added. The polymerization is started as a batch reaction by slowly
metering in the Na.sub.2S.sub.2O.sub.5 solution at 0.01 ml/min. Let
the reaction continue and make adjustments as necessary. Let the
reaction proceed to the desired level of completion by monitoring
system pressure. About 80% solid polymer forms in about 8
hours.
[0089] There are several weak infrared spectral peaks at 1450,
1421, 1380, 1346 and 1070 cm.sup.-1, which are indicative of TFP
incorporation into the polymer. Two peaks appear useful for
quantitation -1346 and 1070 cm.sup.-1. Due to the low level of
hydrogen in the polymer, hydrogen elemental analysis is of marginal
use. However, carbon and fluorine elemental analysis is
satisfactory.
[0090] The CTFE/1234yf copolymer was formed into a film of 1.00 mil
thickness by using a film gauge and a heated carver press.
[0091] The CTFE/1234yf copolymer was tested for moisture permeation
against a CTFE homopolymer and two CTFE/vinylidene difluoride (VF)
copolymers (3 wt % and 5 wt % vinylidene fluoride). The films of
the CTFE homopolymer and two CTFE/vinylidene difluoride (VF)
copolymers were prepared in substantially the same manner as for
the CTFE/1234yf copolymer. Films were typically of 50 cm.sup.2 area
and 1.00 mil thick. A MOCON Water vapor permeation system was used
for the measurements.
[0092] The results showed that the film of the CTFE/1234yf
copolymer exhibited much better moisture barrier performance, i.e.,
lower moisture permeation, than the films of the CTFE/VF
copolymers. A small amount of 1234yf maintains a high degree of
bather protection while modifying and delivering desirable thermal
properties compared to the homopolymer. The results are set forth
in the Table below.
TABLE-US-00001 TABLE Permeability Comparison and Thermal Properties
Water Permeation gm-mil/ Heat Cool Reheat [100 in.sup.2-day]
T.sub.m(.degree. C.) H.sub.f(J/g) T.sub.g(.degree. C.)
T.sub.cc(.degree. C.) H.sub.c(J/g) T.sub.g(.degree. C.)
T.sub.m(.degree. C.) H.sub.f(J/g) Aclar Ultrex 2000 0.0154 211.34
-13.98 182.06 16.99 214.53 -17.15 Homopolymer Aclar VK 22A 0.03
205.91 -11.55 172.07 12.4 51.4 .sup.1 208.04 -12.91 2.5% VF2 Aclar
VX 0.033 165.18 -6.78 46 126.88 6.62 52 174 -8.22 5.0% VF2 NEW
CTFE/1234yf 0.019 190 -4.76 43.7 140.23 4.89 48.8 191.87 -4.53 3.0%
1234yf ACLAR .COPYRGT. is a Honeywell International brand of
Polychlorotrifluoroethylene. ACLAR Ultrex a pure homopolymer film.
ACLAR VK22A is a 2.5 wt % copolymer with vinylidene fluoride.
[0093] The present invention has been described with particular
reference to the preferred embodiments. It should be understood
that variations and modifications thereof can be devised by those
skilled in the art without departing from the spirit and scope of
the present invention. Accordingly, the present invention embraces
all such alternatives, modifications and variations that fall
within the scope of the appended claims.
* * * * *