Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-03-19
2001-12-11
Wilson, Donald R. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S326400, C525S369000, C525S387000
Reexamination Certificate
active
06329471
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing a carboxyl group-containing vinylidene fluoride copolymer and more particularly to a process for producing a carboxyl group-containing vinylidene fluoride copolymer for effective used as an oligomer having a functional group at both terminals.
2. Description of Related Art
Functional oligomers having a carboxyl group at both terminals can be effectively used as a chain-elongating agent for epoxy resin, isocyanate resin, etc., or as raw materials for a solvent-resistant sealant, an adhesive, a coating agent, etc., but carboxyl group-containing fluorine-based copolymers cannot be safely produced at a low cost according to the conventional processes as mentioned below.
U.S. Pat. No. 3,147,314 discloses a process, which comprises boiling a vinylidene fluoride-hexafluoropropene copolymer together with an amine in tetrahydrofuran for a long time, thereby effecting dehydrofluorination reaction, followed by oxidative decomposition of the resulting double bond by KMnO
4
, where not only the dehydrofluorinated copolymer must be once isolated and then subjected to oxidation reaction upon redissolution into acetone, but also the heavy metal Mn used in the oxidative decomposition reaction must be removed. That is, the resulting pollution control is a problem.
Literature “Functional fluorine-containing polymers” pages 11-12 (1982), published by Nikkan Kogyo Shinbun, Japan, discloses a process, which comprises copolymerizing tetrafluoroethylene with CF
2
═CFO(CF
2
)
4
COOCH
3
, followed by hydrolysis of side chain ester groups, where the ester group-containing monomer used in the copolymerization reaction is very expensive and thus is not suitable for industrial application, and also the hydrolysis reaction of the ester group does not fully proceed unless under alkaline conditions and thus is hardly applicable to the vinylidene fluoride-based copolymers.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a process for safely producing a carboxyl group-containing fluorine-based copolymer at a low cost.
Such an object of the present invention can be attained by treating a vinylidene fluoride copolymer with a base and a peroxide, preferably in the presence of a phase-transfer catalyst, thereby producing a carboxyl group-containing vinylidene fluoride copolymer.
DETAILED DESCRIPTION OF THE INVENTION
The vinylidene fluoride copolymer for use in the present invention includes, for example, copolymers of vinylidene fluoride [VdF] with at least one of hexafluoropropene [HFP], tetrafluoroethylene [TFE], perfluoro(methyl vinyl ether) [FMVE], perfluoro(ethyl vinyl ether) [FEVE], perfluoro(propyl vinyl ether) [FPVE], chlorotrifluoroethylene [CTFE], ethylene [E], propylene [P], etc., and more specifically VdF-HFP copolymer, VdF-HFP-TEF terpolymer, VdF-TFE copolymer, VdF-CTFE copolymer, VdF-CTFE-TFE terpolymer, VdF-FMVE copolymer, VdF-FEVE copolymer, VdF-FPVE copolymer, VdF-TFE-FMVE terpolymer, VdF-TFE-FMVE-CTFE quaternary copolymer, VdF-P-TFE terpolymer, VdF-HFP-E-TFE quaternary copolymer, etc.
Vinylidene fluoride copolymers containing about 30 to about 85% by mole, preferably about 75 to about 80% by mole, of vinylidene fluoride and having a weight average molecular weight Mw of about 1×10
5
to about 9×10
5
, preferably about 4.5×10
5
to 7×10
5
, a number average molecular weight Mn of about 0.5×10
5
to about 6×10
5
, preferably about 1.5×10
5
to about 3.5×10
5
and Mooney viscosity ML
1+10
(Method B: MB4-4, 121° C.) of about 5 to about 200, preferably about 20 to about 105, can be used in the present invention. Molecular weights or Mooney viscosities outside the above-mentioned range are not preferable, because of decreases in mechanical characteristics such as tension, elongation, permanent elongation, etc. or poor process ability.
The base for use in the present invention includes, for example, hydroxides and carbonates of alkali metals or alkaline earth metals such as potassium hydroxide, sodium hydroxide, cesium hydroxide, calcium hydroxide, calcium carbonate, etc. and tertiary amines such as triethylamine, etc. The peroxide for use in the present invention includes, for example, hydrogen peroxide, persulfates, organic peroxides (including peracetic acid, organic hydroperoxides, etc.) and the like. Hydrogen peroxide is preferable because of low cost and unnecessary of post-treatment. The base and the peroxide can be added together at the same time or in the order of the base to the peroxide.
When a vinylidene fluoride-hexafluoropropene copolymer typical of the vinylidene fluoride copolymer is treated with KOH and H
2
O
2
, it seems that a vinylidene fluoride-hexafluoropropene copolymer having a carboxyl group at both terminals can be formed according to the following reaction mechanism:
The vinylidene fluoride-hexafluoropropene copolymer is very stable against an oxidizing agent, but is readily dehydrofluorinated in an alkaline medium to form a double bond. Proportion of formed double bond depends uniquely on the amount of the base to be used. For example, when the base is potassium hydroxide, sodium hydroxide or the like, about 0.3 to about 50% by weight, preferably about 3 to about 40% by weight thereof can be used on the basis of the copolymer.
The thus formed double bond is subjected to oxidation reaction with, for example, hydrogen peroxide, as a solution in an organic solvent containing about 5 to about 50% by weight, preferably about 10 to about 30% by weight, of hydrogen peroxide, whereby terminal carboxyl groups can be readily formed. The organic solvent for that purpose includes, for example, any one of vinylidene fluoride copolymer-dissolvable ketones, esters, amides, hydrofluorochlorocarbons, etc. Preferable are acetone, ethyl acetate, etc.
It is desirable from the viewpoint of exothermic control to carry out the treatment with the base and the peroxide at about 0° to about 100° C., preferably about 10° to about 30° C. To improve the reaction rate during the treatment, it is preferable to use a phase-transfer catalyst. As the phase transfer catalyst, about 1 to about 10 parts by weight, preferably about 2 to about 7 parts by weight, of at least one of quaternary ammonium salts and quaternary phosphonium salts represented by the following general formulae can be used on the basis of 100 parts by weight of the copolymer:
(R
1
R
2
R
3
R
4
N)
+
X
−
(R
1
R
2
R
3
R
4
P)
+
X
−
where R
1
to R
4
are each an alkyl group having 1 to 25 carbon atoms, an alkoxy group, an aryl group, an alkylaryl group, an aralkyl group or a polyoxyalkylene group, or two or three of which may form a heterocyclic structure together with N or P; and X
−
is an anion such as Cl
−
, Br
−
, I
−
, HSO
4
−
, H
2
PO
4
−
, RCOO
−
, ROSO
2
−
, RSO
−
, ROPO
2
H
−
, CO
3
−
, etc.
Specifically, the quaternary onium salt includes, for example, quaternary ammonium salts such as tetraethylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, n-dodecyltrimethylammonium bromide, cetyldimethylbenzylammonium chloride, methylcetyl-dibenzylammonium bromide, cetyldimethylethylammonium bromide, octadecyltrimethylammonium bromide, cetylpyridinium chloride, cetylpyridinium bromide, cetylpyridinium iodide, cetyl-pyridinium sulfate, 1-benzylpyridinium chloride, 1-benzyl-3,5-dimethylpyridinium chloride, 1-benzyl-4-phenylpyridinium chloride, 1,4-dibenzylpyridinium chloride, 1-benzyl-4-(pyrrolidinyl)pyridinium chloride, 1-benzyl-4-pyridino-pyridinium chloride, tetraethylammonium acetate, trimethyl-benzylammonium benzoate, trimethylbenzylammonium-p-toluene sulfonate, trimethylbenzylammonium borate, 8-benzyl-1,8-diaza-bicyclo[5,4,0]-undec-7-enium chloride, 1,8-diazabicyclo[5,4,0]-undecen-7-methylammonium
Blagodatova Olga Viktorinovna
Kokotin Igor Vladimirovich
Mizuide Fumiyo
Sokolov Sergey Vasilievich
Tatsu Haruyoshi
Baker & Daniels
Nippon Mektron Limited
Wilson Donald R.
LandOfFree
Process for producing carboxyl group-containing vinylidene... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for producing carboxyl group-containing vinylidene..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for producing carboxyl group-containing vinylidene... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2599422