Dispersibility improver for fluororesin powders, modifier...

Details Dispersibility improver for fluororesin powders, modifier... Dispersibility improver for fluororesin powders, modifier...

1999-06-30

2001-06-26

Dawson, Robert (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

At least one aryl ring which is part of a fused or bridged...

C524S261000, C524S265000, C524S266000, C524S267000, C524S268000, C524S462000, C524S545000, C528S025000, C528S026000, C528S029000, C528S031000, C528S042000

Reexamination Certificate

active

06251975

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to agents that improve the dispersibility (dispersibility improvers) of fluororesin powders, to modifiers for organic resins, and to organic resin compositions. More particularly, this invention relates to a dispersibility improver for fluororesin powders that can induce the uniform dispersion of fluororesin powders in organic resins, to a modifier for organic resins wherein said modifier comprises fluororesin powder and the aforesaid dispersibility improver, and to organic resin compositions that contain the aforesaid modifier and that as a result can form films with an excellent surface smoothness.
BACKGROUND OF THE INVENTION
The admixture of a fluororesin powder, e.g., Teflon™ powder, into organic resins is an already known strategy for improving the physical properties of organic resins. For example, Japanese Laid Open (Kokai or Unexamined) Patent Application Number Hei 9-286911 (286,911/1997) teaches the preparation of a highly impact-resistant polycarbonate resin composition by the addition of fibrillar polytetrafluoroethylene powder to polycarbonate resin. However, since fluororesin powders generally have low surface tensions, it has been quite difficult to achieve homogeneous dispersions of fluororesin powders in relatively high surface tension organic resins. As a result, there has been desire for the appearance of a method that can generate homogeneous dispersions of fluororesin powders in organic resins.
An object of this invention is to provide a dispersibility improver for fluororesin powders that has the ability to induce the uniform dispersion of fluororesin powders in organic resins.
Another object of this invention is to provide a modifier for application to organic resins wherein said modifier comprises fluororesin powder and the dispersibility improver.
An additional object of this invention is to provide organic resin compositions that contain the aforesaid modifier and as a consequence have the ability to form uniform and transparent coatings having an excellent surface smoothness.
SUMMARY OF THE INVENTION
This invention relates to a dispersibility improver for fluororesin powders wherein said dispersibility improver is a polyorganosiloxane whose molecule contains
(F1) at least 1 organic group selected from the group consisting of polyoxyalkylene-functional organic groups, alkyl groups having at least 12 carbon atoms, and polydialkylsiloxane chain-containing organic groups, and
(F2) at least 1 perfluoroalkyl-functional organic group with the general formula —R
2
—X—R
1
—(CF
2
)
a
F wherein R
1
represents C
1
to C
10
divalent hydrocarbon groups, R
2
represents C
1
to C
20
divalent hydrocarbon groups, X is a group with the formula —CO— or —COO—, and a is an integer with a value of at least 3.
This invention additionally relates to a modifier for organic resins comprising (A) fluororesin powder and (B)the polyorganosiloxane dispersibility improver.
The invention also relates to organic resin compositions comprising the admixture of components (A) and (B) into organic resin (C).
DETAILED DESCRIPTION OF THE INVENTION
The polyorganosiloxane (B) used in this invention contains in its molecule (F1) at least 1 organic group selected from the group consisting of polyoxyalkylene-functional organic groups, alkyl groups having at least 12 carbon atoms, and polydialkylsiloxane chain-containing organic groups and (F2) at least 1 perfluoroalkyl-functional organic group with the general formula —R
2
—X—R
1
—(CF
2
)
a
F.
The polyoxyalkylene-functional organic group can be expressed by groups with the general formula —(R
3
)
b
—O—(R
4
O)
c
—R
5
wherein R
3
is a divalent hydrocarbon group; R
4
is a C
1
to C
4
alkylene group; R
5
is the hydrogen atom, a monovalent hydrocarbon group, or an acyl group; b is 0 or 1; and c is an integer from 1 to 300 and preferably is an integer with a value of at least 5. This polyoxyalkylene-functional organic group can be specifically exemplified by:
—C
3
H
6
O(C
2
H
4
O)
12
CH
3
,
—C
3
H
6
O(C
3
H
6
O)
20
CH
3
,
—C
3
H
6
O(C
2
H
4
O)
6
(C
3
H
6
O)
20
CH
3
,
—C
3
H
6
O(C
2
H
4
O)
20
H,
—C
3
H
6
O(C
3
H
6
O)
40
H,
—C
3
H
6
O(C
2
H
4
O)
20
(C
3
H
6
O)
20
H,
—C
3
H
6
O(C
3
H
6
O)
40
COCH
3
, and
—C
3
H
6
O(C
2
H
4
O)
20
(C
3
H
6
O)
20
COCH
3
.
The alkyl having at least 12 carbons can be exemplified by n-dodecyl, n-tetradecyl, n-hexadecyl, and n-octadecyl.
The polydialkylsiloxane chain-containing organic group can be exemplified by groups with the following general formula
wherein R is a substituted or unsubstituted monovalent hydrocarbon group, R
6
is alkylene or alkyleneoxyalkylene, and c is defined as above. This group can be specifically exemplified by groups with the following formulas wherein Me is an abbreviation for the methyl group.
—C
2
H
4
{Me
2
SiO}
40
Me
2
SiC
4
H
9
—C
2
H
4
{Me
2
SiO}
50
SiMe
3
—C
3
H
6
{Me
2
SiO}
40
Me
2
SiC
4
H
9
—C
2
H
4
{Me
2
SiO}
60
SiMe
3
R
1
in the perfluoroalkyl-functional organic groups (F2) represents C
1
to C
10
divalent hydrocarbon groups, among which ethylene and propylene are preferred. R
2
represents C
1
to C
20
divalent hydrocarbon groups and preferably contains at least 3 carbon atoms. Decamethylene is particularly preferred for R
2
. X is the —C(═O)— or —C(═O)O— group, the subscript a is an integer with a value of at least 3, preferably in the range of 4 to 10. The perfluoroalkyl-functional organic group can be specifically exemplified by:
—C
10
H
20
COOC
2
H
4
C
4
F
9
—C
10
H
20
COOC
2
H
4
C
6
F
13
—C
10
H
20
COOC
2
H
4
C
8
F
17
—C
4
H
8
COOC
2
H
4
C
8
F
17
—C
3
H
6
COOC
2
H
4
C
8
F
17
—C
10
H
20
COC
2
H
4
C
8
F
17
—C
3
H
6
COC
3
H
6
C
8
F
17
—C
2
H
4
COC
2
H
4
C
8
F
17
The polyorganosiloxane dispersibility improver can have, for example, a straight-chain, branched-chain, or cyclic molecular structure. In addition, the organic group (F1) is preferably bonded in side-chain position in this polyorganosiloxane, while the perfluoroalkyl-functional organic group with general formula (F2) is preferably bonded therein in side-chain position or molecular chain terminal position. The main chain of this polyorganosiloxane preferably has a degree of polymerization of at least 5. The molecular weight of the subject polyorganosiloxane is preferably from 1,000 to 1,000,000 and more preferably from 10,000 to 100,000. This polyorganosiloxane preferably has a fluorine content from 1 to 70 weight % and more preferably from 5 to 50 weight %. A full development of the ability to stabilize the dispersion of fluororesin powders will not occur at a fluorine content less than 1 weight %, while fluorine contents greater than 70 weight % cause a poor compatibility with organic resins.
Compounds as defined by the following general formula can be provided as typical examples of the polyorganosiloxane dispersibility improver.
R denotes substituted and unsubstituted monovalent hydrocarbon groups and can be specifically exemplified by C
1
to C
30
alkyl, alkenyl, aryl, and arylalkyl. R will typically be methyl or phenyl.
R
F
represents (F2) the perfluoroalkyl-functional organic group with the general formula —R
2
—X—R
1
—(CF
2
)
a
F.
D denotes (F1) the organic group selected from polyoxyalkylene-functional organic groups, alkyl groups having at least 12 carbon atoms, and polydialkylsiloxane chain-containing organic groups.
E is a group selected from R, R
F
, and D.
x is a number with a value from 0 to 500, y is a number from 0 to 500, z is a number from 1 to 500, and (x+y+z) preferably falls in the range from 2 to 1,000 and more preferably in the range from 5 to 1,000. The subscript y may be 0 when at least 1 of the terminal E groups is the perfluoroalkyl-functional organic group (F2).
In addition, the perfluoroalkyl-functional organic group (F2) and the organic group (F1) are preferably bonded in the subject polyorganosiloxane as graft chains along the siloxane backbone of the main chain.
The polyorganosiloxane dispersibility improver can be exemplified by the following compounds wherein Me

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