Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
2000-09-01
2002-07-09
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
C525S431000, C528S015000, C528S026000, C528S028000, C528S031000, C528S032000
Reexamination Certificate
active
06417311
ABSTRACT:
This invention relates to curable compositions which firmly bond to a variety of substrates such as polyphenylene sulfide and nylon while curing into fluorinated elastomers.
BACKGROUND OF THE INVENTION
Curable fluorinated elastomer compositions utilizing addition reaction between alkenyl and hydrosilyl radicals are well known in the art. It is also known from JP-A 9-95615 to add an organopolysiloxane having a hydrosilyl radical and an epoxy and/or trialkoxy radical as a third component to such a composition for rendering it self-adhesive. This composition can be cured by brief heating while it can bond to a variety of substrates during curing. Since the cured product has good solvent resistance, chemical resistance, heat resistance, low-temperature properties, low moisture permeability and electrical properties, the composition is useful in an adhesion application in a variety of industrial fields where such properties are required.
The composition forms a satisfactory bond to such plastics as epoxy resins, phenolic resins and polyester resins, but a less satisfactory bond to such engineering plastics as polyphenylene sulfide (PPS) and nylon. The composition is not applicable where PPS and nylon are used. Since PPS and nylon are often used as casing material, an improvement in bond to these engineering plastics is desired.
SUMMARY OF THE INVENTION
An object of the invention is to provide a novel and improved curable composition which cures into a fluorinated elastomer that firmly bonds to PPS and nylon.
The invention pertains to a curable composition of the addition curing type comprising a fluorinated amide compound having at least one alkenyl radical in a molecule, a fluorinated organohydrogensiloxane, and a platinum group compound. It has been found that by adding to this composition an organosiloxane having in a molecule at least one hydrogen atom directly attached to a silicon atom, and at least one epoxy and/or trialkoxysilyl radical attached to a silicon atom through a carbon atom or a carbon atom and an oxygen atom, and preferably further having a perfluoroalkyl or perfluoropolyether radical, as a tackifier and further adding a carboxylic anhydride as an adhesion reaction promoter, there is obtained a curable composition which cures into a fluorinated elastomer that not only has good solvent resistance, chemical resistance, heat resistance, low-temperature properties, low moisture permeability and electrical properties, but also firmly bonds to a variety of substrates including PPS and nylon.
Accordingly, the invention provides a curable composition comprising as essential components,
(A) a fluorinated amide compound having at least one alkenyl radical in a molecule,
(B) a fluorinated organohydrogensiloxane,
(C) a platinum group compound,
(D) an organosiloxane having in a molecule at least one hydrogen atom directly attached to a silicon atom, and at least one of epoxy radicals and trialkoxysilyl radicals each attached to a silicon atom through a carbon atom or a carbon atom and an oxygen atom, and
(E) a carboxylic anhydride.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Briefly stated, the curable composition of the invention contains (A) a fluorinated amide compound having an alkenyl radical as a base polymer, (B) a fluorinated organohydrogensiloxane as a crosslinker and chain extender, (C) a platinum group compound as a catalyst, (D) an organosiloxane as a tackifier, and (E) a carboxylic anhydride as an adhesion promoter.
Component (A) is a fluorinated amide compound which should have at least one alkenyl radical in a molecule, and preferably two alkenyl radicals at opposite ends. In the compound, fluorine is preferably contained as a monovalent perfluoroalkyl, monovalent perfluoropolyether, divalent perfluoroalkylene or divalent perfluoropolyether radical. Preferably the compound has the following linkage.
Further, the compound may have the following linkage.
The fluorinated amide compound (A) is preferably of the following general formula (1).
Herein R
1
is a substituted or unsubstituted monovalent hydrocarbon radical. R
2
is hydrogen or a substituted or unsubstituted monovalent hydrocarbon radical. Q is a radical of the following general formula (2) or (3):
wherein R
3
is a substituted or unsubstituted divalent hydrocarbon radical which may be separated by at least one atom of oxygen, nitrogen and silicon atoms, and R
2
is as defined above,
wherein R
4
and R
5
each are a substituted or unsubstituted divalent hydrocarbon radical. Rf is a divalent perfluoroalkylene or perfluoropolyether radical, and “a” is an integer of at least 0.
Referring to formula (1), R
1
stands for substituted or unsubstituted monovalent hydrocarbon radicals preferably of 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and also preferably free of aliphatic unsaturation. Examples include alkyl radicals such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, octyl and decyl; cycloalkyl radicals such as cyclopentyl, cyclohexyl and cycloheptyl; alkenyl radicals such as vinyl, allyl, propenyl, isopropenyl, butenyl, and hexenyl; aryl radicals such as phenyl, tolyl, xylyl and naphthyl; aralkyl radicals such as benzyl, phenylethyl and phenylpropyl; and substituted ones of these radicals in which some or all of the hydrogen atoms are replaced by halogen atoms or the like, typically fluorinated alkyl radicals such as chloromethyl, chloropropyl, bromoethyl, 3,3,3-trifluoropropyl, and 6,6,6,5,5,4,4,3,3-nonafluorohexyl.
R
2
stands for hydrogen or substituted or unsubstituted monovalent hydrocarbon radicals preferably of 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and also preferably free of aliphatic unsaturation, as defined above for R
1
. Examples of the monovalent hydrocarbon radicals are as exemplified above for R
1
, for example, alkyl radicals such as methyl, ethyl, propyl, and isopropyl; cycloalkyl radicals such as cyclohexyl; alkenyl radicals such as vinyl and allyl; aryl radicals such as phenyl and tolyl; and substituted ones of these radicals in which some hydrogen atoms are replaced by halogen atoms or the like, typically fluorinated alkyl radicals such as chloromethyl, chloropropyl, 3,3,3-trifluoropropyl, and 6,6,6,5,5,4,4,3,3-nonafluorohexyl.
Q is a radical of the following general formula (2) or (3).
R
2
in formula (2) is as defined above. R
3
may be selected from substituted or unsubstituted divalent hydrocarbon radicals, preferably from divalent hydrocarbon radical of 1 to 20 carbon atoms, especially 2 to 10 carbon atoms. Examples include alkylene radicals such as methylene, ethylene, propylene, methylethylene, butylene and hexamethylene; cycloalkylene radicals such as cyclohexylene; arylene radicals such as phenylene, tolylene, xylylene, naphthylene and biphenylene; substituted ones of these radicals in which some hydrogen atoms are replaced by halogen atoms or the like; and combinations of these substituted or unsubstituted alkylene and arylene radicals.
R
3
may contain one or more atoms of oxygen, nitrogen and silicon atoms at an intermediate of its linkage. In this case, the oxygen atom intervenes in the linkage of R
3
in the form of —O—. The nitrogen atom intervenes in the linkage of R
3
in the form of —NR′— wherein R′ is hydrogen, alkyl of 1 to 8 carbon atoms, especially 1 to 6 carbon atoms or aryl. The silicon atom intervenes in the linkage of R
3
in the form of a straight or cyclic organosiloxane-containing radical or organosilylene radical as shown below.
Herein, R″ is an alkyl radical of 1 to 8 carbon atoms or aryl radical as exemplified for R
1
and R
2
, R″′ is an alkylene radical of 1 to 6 carbon atoms or arylene radical as exemplified for R
3
, and n is an integer of 0 to 10, especially 0 to 5.
Examples of these radicals are given below.
In the above formulae, Me is methyl.
In formula (3), R
4
and R
5
are substituted or unsubstituted divalent hydrocarbon radicals of 1 to 10 carbon atoms, especially 2 to 6 carbon atoms. Illustrative are alkylene radicals such as methylene,
Fukuda Ken-ichi
Shiono Mikio
Dawson Robert
Zimmer Marc S.
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