U.S. patent application number 11/070160 was filed with the patent office on 2005-09-15 for fluoropolyether adhesive composition.
This patent application is currently assigned to Shin-Etsu Chemical Co., Ltd.. Invention is credited to Shiono, Mikio.
Application Number | 20050202260 11/070160 |
Document ID | / |
Family ID | 34752209 |
Filed Date | 2005-09-15 |
United States Patent
Application |
20050202260 |
Kind Code |
A1 |
Shiono, Mikio |
September 15, 2005 |
Fluoropolyether adhesive composition
Abstract
An adhesive composition comprising the following components: (A)
a linear polyfluoro compound having at least two SiH bonds per
molecule and a perfluoropolyether residue in a main chain of the
linear polyfluoro compound (A); (B) an organohydrogensiloxane
having a fluorinated group and at least two hydrogen atoms each
bonded to a silicon atom per molecule; (C) a compound of a platinum
group metal; (D) hydrophobic silica powder; (E) an alkoxysilane
represented by the following formula (1) (RO).sub.3--Si--T (1)
wherein R is a monovalent hydrocarbon group, T is a group
represented by the formula, --OR.sup.1 or --CHR.sup.2--COOR.sup.3,
wherein R.sup.1 is a monovalent hydrocarbon group, which may be the
same with or different from R, R.sup.2 is a hydrogen atom or a
methyl group and R.sup.3 is a monovalent hydrocarbon group; and (F)
an organosiloxane having at least one SiH bond and at least one
group selected from the group consisting of an epoxy group and a
trialkoxysilyl group. The composition has no quality variation from
lot to lot and gives gives a cured product having good resistance
to solvents and heat, and durability.
Inventors: |
Shiono, Mikio; (Annaka-shi,
JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
Shin-Etsu Chemical Co.,
Ltd.
|
Family ID: |
34752209 |
Appl. No.: |
11/070160 |
Filed: |
March 3, 2005 |
Current U.S.
Class: |
428/448 ;
525/403 |
Current CPC
Class: |
C08L 83/08 20130101;
C08K 5/541 20130101; C09J 171/02 20130101; C08K 5/5419 20130101;
C08L 71/02 20130101; C08L 83/00 20130101; C09J 183/08 20130101;
C08L 71/02 20130101; C08L 83/08 20130101; C09J 183/08 20130101;
C08L 83/00 20130101; C08L 2666/14 20130101; C08L 83/00 20130101;
C08L 2666/14 20130101; C09J 171/02 20130101; C08G 65/007 20130101;
C08L 2666/14 20130101; C08G 65/336 20130101 |
Class at
Publication: |
428/448 ;
525/403 |
International
Class: |
B32B 009/04; C08G
065/32; C08L 071/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 5, 2004 |
JP |
2004-063206 |
Feb 25, 2005 |
JP |
2005-051162 |
Claims
1. An adhesive composition comprising the following components: 100
parts by weight of (A) a linear polyfluoro compound having at least
two alkenyl groups per molecule and a perfluoropolyether residue in
a main chain of the linear polyfluoro compound (A); (B) an
organohydrogensiloxane having a fluorinated group and at least two
SiH bonds per molecule in such an amount that a molar amount of the
SiH bond is 0.5 to 3.0 times that of the alkenyl group contained in
the component (A); (C) 0.1 to 500 ppm of a compound of a platinum
group metal in an amount of, calculated as platinum group metal,
based on 100 parts by weight of the component (A); 0.5 to 30 parts
by weight of (D) hydrophobic silica powder; 0.5 to 15 parts by
weight, per 100 parts by weight of the component (D), of (E) an
alkoxysilane represented by the following formula (1)
(RO).sub.3--Si--T (1) wherein R may be the same with or different
from each other and is a monovalent hydrocarbon group, T is a group
represented by the formula, --OR.sup.1 or --CHR.sup.2--COOR.sup.3,
wherein R.sup.1 is a monovalent hydrocarbon group, which may be the
same with or different from R, R.sup.2is a hydrogen atom or a
methyl group and R.sup.3 is a monovalent hydrocarbon group; and 0.1
to 10 parts by weight of (F) an organosiloxane having at least one
SiH bond and at least one group selected from the group consisting
of an epoxy group and a trialkoxysilyl group, said at least one
group being bonded to a silicon atom of the organosiloxane (F) via
an organic group which may contain an oxygen atom.
2. The adhesive composition according to claim 1, wherein R,
R.sup.1 and R.sup.3 of the component (E) may be the same with or
different from each other and are monovalent hydrocarbon groups
having 1 to 8 carbon atoms and no aliphatic unsaturated bond.
3. The adhesive composition according to claim 1, wherein the
component (A) is represented by the following formula (2)
CH.sub.2.dbd.CH--(X).sub.-
a--R.sub.f.sup.1--(X').sub.a--CH.dbd.CH.sub.2 (2) wherein X is
--CH.sub.2--, --CH.sub.2O--, --CH.sub.2OCH.sub.2--, or
--Y--NR'--CO--, wherein Y is --CH.sub.2-- or an o- , m- , or
p-dimethylsilylphenylene group represented by the following formula
(Z) 28and R' is a hydrogen atom or a monovalent hydrocarbon group
of which hydrogen atom may be replaced with a halogen atom, X' is
--CH.sub.2--, --OCH.sub.2--, --CH.sub.2OCH.sub.2--, or
--CO--NR'--Y'--, wherein Y' is --CH.sub.2-- or an o- , m- , or
p-dimethylsilylphenylene group represented by the following formula
(Z') 29and R' is a hydrogen atom or a monovalent hydrocarbon group
of which hydrogen atom may be replaced with a halogen atom, "a" is
an integer of 0 or 1 and may be the same with or different from
each other; R.sub.f.sup.1 is a divalent perfluoropolyether group
represented by the following formula (i) or (ii):
--C.sub.tF.sub.2t[OCF.s- ub.2CF(CF.sub.3)].sub.bO(CF.sub.2).sub.LO
[CF(CF.sub.3)CF.sub.2O].sub.cC.s- ub.tF.sub.2t-- (i) wherein b and
c are integers of from 0 to 200 with an average of a sum, b+c,
ranging from 2 to 200, L is an integer of from 2 to 6 and t is an
integer of 2 or 3, --C.sub.tF.sub.2t[OCF.sub.2CF(CF.sub.- 3)
].sub.u(OCF.sub.2).sub.vOC.sub.tF.sub.2t-- (ii) wherein u is an
integer of from 1 to 200, v is an integer of from 1 to 50, with an
average of a sum, u+v, ranging from 2 to 200, and t is an integer
of 2 or 3.
4. The adhesive composition according to claim 1, wherein the
organohydrogensiloxane (B) has at least one group selected from the
group consisting of perfluoroalkyl groups, perfluoroxyalkyl groups,
perfluoroalkylene groups, and perfluoroxyalkylene groups.
5. The adhesive composition according to claim 1, wherein the
hydrophobic silica powder (D) is a fumed silica having been surface
treated with at least one selected from the group consisting of
organochlorosilanes, organodisilazanes, and cyclic
organopolysilazanes.
6. The adhesive composition according to claim 1, wherein the
organosiloxane (F) has at least one group selected from the group
consisting of perfluoroalkyl groups and perfluoroxyalkyl groups,
said at least one group being bonded to a silicon atom of the
organosiloxane (F) via an organic group which may contain an oxygen
atom.
7. A part of an automobile control system, characterized in that
said part has a protective seal or a coating prepared from the
adhesive composition according to any one of the claims 1 to 6.
8. A part of a printer, characterized in that said part has a
protective seal or a coating prepared from the adhesive composition
according to any one of the claims 1 to 6.
9. A printer comprising the part according to claim 8.
Description
CROSS REFERENCES
[0001] This application claims benefits of Japanese Patent
Applications No. 2004-063206 filed on Mar. 5, 2004, and
No.2005-51162 filed on Feb. 25, 2005, the contents of which are
hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an adhesive composition
which is self-adhesive to various kinds of substrates such as
metals and plastics. The composition, when cured, gives a
fluorinated elastomer adhering strongly to a substrate with
excellent long-term durability.
DESCRIPTION OF THE PRIOR ART
[0003] A curable composition is known which forms a fluorinated
elastomer by addition reaction between alkenyl groups and
hydrosilyl groups contained in the composition. Japanese Patent
Application Laid-Open No.9-95615 discloses a composition which
comprises, in addition to the aforesaid curable composition, an
organopolysiloxane having hydrosilyl groups and epoxy groups and/or
trialkoxysilyl groups to thereby have a self-adherence property.
Japanese Patent Application Laid-Open No.2001-220509 discloses a
composition which further comprises silica powder surface-treated
with a fluorinated organosilane or a fluorinated organosiloxane to
thereby improve durability of a cured product thereof.
[0004] These compositions can be cured in a short period of time to
give cured products having resistance to solvents, chemicals and
heat, good low temperature property, low moisture permeability, and
good electrical properties. For this reason, the compositions are
used as adhesives in various industries where the above properties
are required, particularly in the automobile industry, for sealing
or coating of electric and electronic automobile parts.
[0005] However, the adhesive composition comprising the silica
powder has a drawback. That is, adhesion strength and durability of
a cured product therefrom vary depending on the amount of moisture
adsorbed on the silica powder. Further, the higher the adsorbed
moisture content is, the lower the adhesion strength and durability
tend to be. This variation in properties is detrimental in the
automobile industry where quality stability of automobile parts is
crucial. Therefore, an adhesive composition is desired which shows
no quality variation from lot to lot and gives an adhesive layer
having long-term reliability.
SUMMARY OF THE INVENTION
[0006] A purpose of the present invention is to provide an adhesive
composition which has no quality variation from lot to lot; can be
cured by heating for a short period of time to adhere strongly to
substrates of various kinds of materials such as metals and
plastics; and gives a cured product having good resistance to
solvents and heat, low moisture permeability and durability.
[0007] The inventor has found that the above purpose is attained by
incorporating specific alkoxysilane in an adhesive composition
[0008] Thus, the present invention is an adhesive composition
comprising the following components:
[0009] 100 parts by weight of (A) a linear polyfluoro compound
having at least two alkenyl groups per molecule and a
perfluoropolyether residue in a main chain of the linear polyfluoro
compound (A);
[0010] (B) an organohydrogensiloxane having a fluorinated group and
at least two SiH bonds per molecule in such an amount that a molar
amount of the SiH bond is 0.5 to 3.0 times that of the alkenyl
group contained in the component (A);
[0011] (C) 0.1 to 500 ppm of a compound of a platinum group metal
in an amount of, calculated as platinum group metal, based on 100
parts by weight of the component (A);
[0012] 0.5 to 30 parts by weight of (D) hydrophobic silica
powder;
[0013] 0.5 to 15 parts by weight, per 100 parts by weight of the
component (D), of (E) an alkoxysilane represented by the following
formula (1)
(RO).sub.3--Si--T (1)
[0014] wherein R may be the same with or different from each other
and is a monovalent hydrocarbon group,
[0015] T is a group represented by the formula, --OR.sup.1 or
--CHR.sup.2--COOR.sup.3, wherein R.sup.1 is a monovalent
hydrocarbon group, which may be the same with or different from R,
R.sup.2is a hydrogen atom or a methyl group and R.sup.3 is a
monovalent hydrocarbon group; and
[0016] 0.1 to 10 parts by weight of (F) an organosiloxane having at
least one SiH bond and at least one group selected from the group
consisting of an epoxy group and a trialkoxysilyl group, said at
least one group being bonded to a silicon atom of the
organosiloxane (F) via an organic group which may contain an oxygen
atom.
[0017] The present composition comprises the specific alkoxysilane
of the formula (1) above to thereby be free from the aforesaid
problem caused by moisture adsorbed on silica powder. The
composition adheres well to various kinds of materials such as
metals and plastics. An adhesive layer formed by heating the
composition at a relatively low temperature for a short period of
time has excellent resistance to solvents, heat, low moisture
permeability and durability. The composition is useful for sealing
and coating electric or electrical parts in the industries where
stable quality and long-term reliability are required.
PREFERRED EMBODIMENTS OF THE INVENTION
[0018] Each component of the present adhesive composition will be
explained below.
[0019] (A) Linear Polyfluoro Compound
[0020] The linear polyfluoro compound (A) has at least two alkenyl
groups per molecule. Preferably, the linear polyfluoro compound (A)
is represented by the following formula (2),
CH.sub.2--CH--(X).sub.a--R.sub.f.sup.1--(X').sub.a--CH.dbd.CH.sub.2
(2)
[0021] wherein X is --CH.sub.2--, --CH.sub.2O--,
--CH.sub.2OCH.sub.2--, or --Y--NR'--CO--, wherein Y is --CH.sub.2--
or an o- , m- , or p-dimethylsilylphenylene group represented by
the following formula (Z) 1
[0022] and R' is a hydrogen atom or a monovalent hydrocarbon group
of which hydrogen atom may be replaced with a halogen atom,
[0023] X' is --CH.sub.2--, --OCH.sub.2--, --CH.sub.2OCH.sub.2--, or
--CO--NR'--Y'--, wherein Y' is --CH.sub.2-- or an o- , m- , or
p-dimethylsilylphenylene group represented by the following formula
(Z') 2
[0024] and R' is a hydrogen atom or a monovalent hydrocarbon group
of which hydrogen atom may be replaced with a halogen atom,
[0025] "a" is an integer of 0 or 1 and may be the same with or
different from each other; and
[0026] R.sub.f.sup.1 is a divalent perfluoropolyether group.
[0027] Examples of R', besides a hydrogen atom, include monovalent
hydrocarbon groups having 1 to 12 carbon atoms, preferably 1 to 10
atoms, for example, alkyl groups such as methyl, ethyl, propyl,
butyl, hexyl, cyclohexyl, and octyl groups; aryl groups such as
phenyl group and tolyl groups; aralkyl groups such as benzyl group
and phenylethyl groups; and halogenated groups thereof wherein a
part of or all of the hydrogen atoms are replaced with a halogen
atom such as a fluorine atom. Among these, a methyl group and a
phenyl group are preferred.
[0028] In the formula (2), R.sub.f.sup.1 is a divalent
perfluoropolyether group, preferably the one represented by the
following formula (i) or (ii):
--C.sub.tF.sub.2t[OCF.sub.2CF(CF.sub.3)].sub.bO(CF.sub.2).sub.LO[CF(CF.sub-
.3)CF.sub.2O].sub.cC.sub.tF.sub.2t-- (i)
[0029] wherein b and c are integers of from 0 to 200 with an
average of a sum, b+c, ranging from 2 to 200, L is an integer of
from 2 to 6 and t is an integer of 2 or 3,
--C.sub.tF.sub.2t[OCF.sub.2CF(CF.sub.3)].sub.u(OCF.sub.2).sub.vOC.sub.tF.s-
ub.2t-- (ii)
[0030] wherein u is an integer of from 1 to 200, v is an integer of
from 1 to 50, with an average of a sum, u+v, ranging from 2 to 200,
and t is an integer of 2 or 3.
[0031] Preferred examples of R.sub.f.sup.1 are represented by the
following formulae, among which the first one is especially
preferred. 3
[0032] wherein m and n are integers of 1 or larger with an average
of a sum, m+n, ranging from 2 to 200; 4
[0033] wherein m and n are integers of 1 or larger with an average
of a sum, m+n, ranging from 2 to 200; and 5
[0034] wherein m is an integer of from 1 to 200 and n is an integer
of from 1 to 50.
[0035] Preferably, the linear polyfluoro compound (A) is
represented by the following formula (3). 6
[0036] wherein X and X' are as already explained above, "a" may be
the same with or different from each other and is an integer of 0
or 1, L is an integer of from 2 to 6, and b and c are both integers
of from 1 to 150 with an average of a sum, b+c, ranging from 2 to
200.
[0037] Examples of the linear polyfluoro compound of the formula
(3) are as shown below. 7
[0038] In the above formulae, m and n are integers of from 1 to 200
with m+n ranging from 6 to 200.
[0039] Preferably, the linear polyfluoro compound (A) has a
viscosity of from 100 to 100,000 mPa.s, more preferably from 500 to
50,000 mPa.s, and most preferably from 1,000 to 20,000 mPa.s at 23
degrees C. Particularly for sealing, potting, coating or
impregnation application, the viscosity in the above range is
preferred because of excellent physical properties both at a time
of applying the composition and a time after curing. The above
linear polyfluoro compounds may be used alone or in a mixture of
two or more of them.
[0040] (B) Organohydrogensiloxane
[0041] The organohydrogensiloxane (B) has at least two SiH bonds
per molecule and a fluorinated group. The organohydrogensiloxane
(B) functions as a crosslinking agent or a chain extender for the
linear polyfluoro compound (A). Preferably, the
organohydrogensiloxane (B) has at least one fluorinated group
selected from the group consisting of perfluoroalkyl groups,
perfluoroxyalkyl groups, perfluoroalkylene groups and
perfluoroxyalkylene groups from the viewpoint of good miscibility
with the linear polyfluoro compound (A), uniform properties of the
composition and, accordingly, of a cured product.
[0042] Examples of such fluorinated groups are represented by the
following formulae.
C.sub.gF.sub.2g+1--
[0043] wherein g is an integer of from 1 to 20, preferably from 2
to 10;
--C.sub.gF.sub.2g--
[0044] wherein g is an integer of from 1 to 20, preferably from 2
to 10; 8
[0045] wherein f is an integer of from 2 to 200, preferably from 2
to 100, and h is an integer of from 1 to 3; 9
[0046] wherein i and j are integers of at least 1 with an average
of a sum, i+j, ranging from 2 to 200, preferably from 2 to 100;
and
--(CF.sub.2O).sub.e--(CF.sub.2CF.sub.2O).sub.l--CF.sub.2--
[0047] wherein e and l are integers of from 1 to 50.
[0048] The perfluoroalkyl group, perfluoroxyalkyl group,
perfluoroalkylene group, or perfluoroxyalkylene group may be bonded
to a silicon atom via a divalent group such as an alkylene group,
an arylene group and a combination thereof, which divalent group
may have an ether, an amide, or a carbonyl group. Examples of the
divalent group include those having 2 to 12 carbons shown
below.
--CH.sub.2CH.sub.2--
--CH.sub.2CH.sub.2CH.sub.2--
--CH.sub.2CH.sub.2CH.sub.2OCH.sub.2--
--CH.sub.2CH.sub.2CH.sub.2--NH--CO--
--CH.sub.2CH.sub.2CH.sub.2--N(Ph)--CO--
--CH.sub.2CH.sub.2CH.sub.2--N(CH.sub.3)--CO--
--CH.sub.2CH.sub.2CH.sub.2--O--CO--
[0049] wherein "Ph" represents a phenyl group.
[0050] Examples of the organohydrogensiloxane (B) having aforesaid
fluorinated group include the compounds represented by the
following formulae, which may be used alone or in a mixture of two
or more of them. In the formulae below, "Me" represents a methyl
group and "Ph" represents a phenyl group. 10111213141516
[0051] In the above formulae, n and m are integers of from 1 to 50
with a sum, n+m, ranging from 2 to 50.
[0052] The organohydrogensiloxane (B) is incorporated in the
composition in an amount enough to form a cured product through a
reaction with the linear polyfluoro-compound (A). Typically, the
organohydrogensiloxane (B) is incorporated in such an amount that a
molar amount of the SiH bond therein is 0.5 to 3.0 times,
preferably 0.8 to 2.0 times, that of the alkenyl group such as a
vinyl, an allyl, or a cycloalkenyl group present in the component
(A). With a less amount of SiH bond than the aforesaid lower limit,
a cured product may not be obtained which has a sufficient degree
of crosslinking and thus sufficient hardness. On the other hand, a
larger amount of SiH bond than the aforesaid upper limit may cause
foaming during curing process.
[0053] (C) Compound of a Platinum Group Metal
[0054] The compound of a platinum group metal (C) is a
hydrosilylation catalyst. The hydrosilylation catalyst promotes an
addition reaction between the alkenyl groups in the component (A)
and the SiH bonds in the component (B). Generally, the
hydrosilylation catalyst is a compound of a noble metal. Platinum
or a platinum compound is widely used because they are readily
available.
[0055] Examples of the platinum compound include hydrogen
chloroplatinic acid, a complex of hydrogen chloroplatinic acid with
an olefin such as ethylene, an alcohol, or a vinylsiloxane,
metallic platinum supported on silica, alumina or carbon. Compounds
of other platinum group metal than platinum may be used, for
example, compounds of rhodium, ruthenium, iridium, and palladium,
such as RhCl(PPh.sub.3).sub.3, RhCl(CO)(PPh.sub.3).sub.2,
Ru.sub.3(CO).sub.l2, IrCl(CO)(PPh.sub.3).sub.2- , and
Pd(PPh.sub.3).sub.4, wherein "Ph" represents a phenyl group.
[0056] The compound of a platinum group metal (C) may be used in a
solid form, but preferably used in a solution, for example, a
solution of chloroplatinic acid or the chloroplatinic acid complex
with an olefin such as an ethylene in an appropriated solvent in
the viewpoint of good miscibility with the linear polyfluoro
compound (A).
[0057] The component (C) is used in a catalytic amount, typically
ranging 0.1 to 500 ppm, calculated as platinum group metal, based
on 100 parts by weight of the component (A).
[0058] (D) Hydrophobic Silica Powder
[0059] The hydrophobic silica powder (D) provides physical strength
in a cured product and makes (F) the organosiloxane dispersed
uniformly in the composition. The hydrophobic silica powder (D) may
be prepared by treating silica fine powder which is known as a
filler in silicone rubber and has a BET specific surface area of at
least 50 m.sup.2/g, particularly from 50 to 400 m.sup.2/g, with a
surface treatment agent which will be explained below.
[0060] With silica powder having a BET specific surface area
smaller than the aforesaid lower limit, physical strength of a
cured product may be too low, and the component (F) may not be
dispersed uniformly in the composition. Silica powder having a BET
specific surface area exceeding the aforesaid upper limit may be
difficult to be dispersed uniformly in a composition. Examples of
the silica powder (D) include fumed silica, precipitated silica and
colloidal silica, among which fumed silica is most preferred.
[0061] The aforesaid silica fine powder may be surface treated with
an agent for hydrophobicity selected from the group consisting of
organochlorosilanes, organodisilazanes, cyclic organopolysilazanes,
and linear organopolysiloxane, among which organochlorosilanes,
organodisilazanes and cyclic organopolysilazanes are preferred.
[0062] The hydrophobic silica powder (D) may be incorporated in the
composition in an amount of from 0.5 to 30 parts by weight,
preferably 1.0 to 25 parts by weight, per 100 parts by weight of
the component (A). A composition comprising the silica in an amount
less than the aforesaid lower limit may not adhere well or give a
cured product with unsatisfactory adhesion strength. On the other
hand, a composition comprising the silica in an amount exceeding
the aforesaid upper limit may not flow properly and also give a
cured product with unsatisfactory adhesion strength.
[0063] (E) Alkoxysilane
[0064] In the present composition, the alkoxysilane (E) is
represented by the following formula (1)
(RO).sub.3--Si--T (1)
[0065] wherein R may be the same with or different from each other
and is a monovalent hydrocarbon group, T is a group represented by
the formula, --OR.sup.1 or --CHR.sup.2--COOR.sup.3, wherein R.sup.1
may be the same with or different from R and is a monovalent
hydrocarbon group, R.sup.2 is a hydrogen atom or a methyl group,
and R.sup.3 is a monovalent hydrocarbon group.
[0066] In the formula (1), preferred examples of R include
monovalent hydrocarbon groups having 1 to 8, preferably 1 to 4,
carbon atoms and preferably having no aliphatic unsaturated bond,
for example, alkyl groups such as methyl, ethyl, propyl, isopropyl,
butyl, isobutyl, tert-butyl, pentyl, hexyl, and octyl groups;
cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl
groups; aryl groups such as phenyl, tolyl, and xylyl groups; and
aralkyl groups such as benzyl, and phenylethyl groups. Among these,
a methyl, an ethyl, a propyl, an isopropyl, a butyl, an isobutyl,
and a tert-butyl groups are preferred.
[0067] In the formula (1), T is a group represented by the formula,
--OR.sup.1 or --CHR.sup.2--COOR.sup.3. In the group, --OR.sup.1 ,
R.sup.1 is a monovalent hydrocarbon group which may be the same
with or different from the aforesaid R.
[0068] In the group, --CHR.sup.2--COOR.sup.3, R.sup.2 is a hydrogen
atom or a methyl group and R.sup.3 is a monovalent hydrocarbon
group having 1 to 8, preferably 1 to 4, carbon atoms which
preferably has no aliphatic unsaturated bond. Examples of R.sup.3
include alkyl groups such as methyl, ethyl, propyl, isopropyl,
butyl, isobutyl, tert-butyl, pentyl, hexyl, and octyl groups;
cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl
groups; aryl groups such as phenyl, tolyl, and xylyl groups; and
aralkyl groups such as benzyl, and phenylethyl groups. Among these,
alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl,
isobutyl, and tert-butyl groups are preferred.
[0069] The alkoxysilane of the formula (1) can be prepared by a
method known to the silicone industry. For example, it can be
prepared by subjecting tetrahalogenosilane to a reaction with an
alcohol, R.sup.1OH, in the presence of a dehydrohalogenation
agent.
[0070] Examples of the alkoxysilane are represented by the
following formulae. These alkoxysilane may be used alone or in a
combination of two or more of them.
(CH.sub.3O).sub.4Si
(C.sub.2H.sub.5O).sub.4Si
(C.sub.2H.sub.5O).sub.3SiOCH.sub.3
(n--C.sub.3H.sub.7O).sub.4Si
(n--C.sub.3H.sub.7O).sub.3SiOCH.sub.3
(n--C.sub.3H.sub.7O).sub.3SiOC.sub.2H.sub.5
(i--C.sub.3H.sub.7O).sub.4Si
(i--C.sub.3H.sub.7O).sub.3SiOCH.sub.3
(i--C.sub.3H.sub.7O).sub.3SiOC.sub.2H.sub.5
(n--C.sub.4H.sub.9O).sub.3SiOCH.sub.3
(n--C.sub.4H.sub.9O).sub.3SiOC.sub.2H.sub.5
(i--C.sub.4H.sub.9O).sub.3SiOCH.sub.3
(i--C.sub.4H.sub.9O).sub.3SiOC.sub.2H.sub.5
(t--C.sub.4H.sub.9O).sub.3SiOCH.sub.3
(t--C.sub.4H.sub.9O).sub.3SiOC.sub.2H.sub.5
[0071] The alkoxysilane of the formula
(RO).sub.3--Si--CHR.sup.2--COOR.sup- .3 may be prepared by
different methods depending on the type of R.sup.2. The one with
R.sup.2 being a hydrogen atom may be prepared by subjecting a
tetraalkoxysilane of the following formula (4) to a reaction with
bromoacetate of the following formula (5) in the presence of zing
powders.
(RO).sub.4--Si (4)
[0072] wherein R is as defined above,
BrCH.sub.2--COOR.sup.3 (5)
[0073] wherein R.sup.3 is as defined above,
[0074] Examples of the alkoxysilane are represented by the
following formulae. These may be used alone or in a mixture of two
or more of them.
(CH.sub.3O).sub.3SiCH.sub.2COOCH.sub.3
(CH.sub.3O).sub.3SiCH.sub.2COOC.sub.2H.sub.5
(CH.sub.3O).sub.3SiCH.sub.2COOC.sub.3H.sub.7--n
(CH.sub.3O).sub.3SiCH.sub.2COOC.sub.3H.sub.7--i
(CH.sub.3O).sub.3SiCH.sub.2COOC.sub.4H.sub.9--n
(CH.sub.3O).sub.3SiCH.sub.2COOC.sub.4H.sub.9--i
(CH.sub.3O).sub.3SiCH.sub.2COOC.sub.4H.sub.9--t
(CH.sub.3O).sub.3SiCH.sub.2COOC.sub.8H.sub.17--n
(C.sub.2H.sub.5O).sub.3SiCH.sub.2COOCH.sub.3
(C.sub.2H.sub.5O).sub.3SiCH.sub.2COOC.sub.2H.sub.5
(C.sub.2H.sub.5O).sub.3SiCH.sub.2COOC.sub.3H.sub.7--n
(C.sub.2H.sub.5O).sub.3SiCH.sub.2COOC.sub.3H.sub.7--i
(C.sub.2H.sub.5O).sub.3SiCH.sub.2COOC.sub.4H.sub.9--n
(C.sub.2H.sub.5O).sub.3SiCH.sub.2COOC.sub.4H.sub.9--i
(C.sub.2H.sub.5O).sub.3SiCH.sub.2COOC.sub.4H.sub.9--t
[0075] The alkoxysilane with R.sup.2being a methyl group may be
prepared by subjecting an organohydrogensiloxne of the following
formula (6) to a reaction with an acrylate of the formula (7) in
the presence of a platinum catalyst.
(RO).sub.3--Si--H (6)
[0076] wherein R is as defined above;
CH.sub.2.dbd.CH--COOR.sup.3 (7)
[0077] wherein R.sup.3 is as defined above;
[0078] Preferably, the alkoxysilane obtained is isolated and
purified by, for instance, distillation, after the reaction.
[0079] Examples of the alkoxysilane are represented by the
following formulae. These may be used alone or in a mixture of two
or more of them.
(CH.sub.3O).sub.3SiCH(CH.sub.3)COOCH.sub.3
(CH.sub.3O).sub.3SiCH(CH.sub.3)COOC.sub.2H.sub.5
(CH.sub.3O).sub.3SiCH(CH.sub.3)COOC.sub.3H.sub.7--n
(CH.sub.3O).sub.3SiCH(CH.sub.3)COOC.sub.3H.sub.7--i
(CH.sub.3O).sub.3SiCH(CH.sub.3)COOC.sub.4H.sub.9--n
(CH.sub.3O).sub.3SiCH(CH.sub.3)COOC.sub.4H.sub.9--i
(CH.sub.3O).sub.3SiCH(CH.sub.3)COOC.sub.4H.sub.9--t
(CH.sub.3O).sub.3SiCH(CH.sub.3)COOC.sub.8H.sub.17--n
(C.sub.2H.sub.5O).sub.3SiCH(CH.sub.3)COOCH.sub.3
(C.sub.2H.sub.5O).sub.3SiCH(CH.sub.3)COOC.sub.2H.sub.5
(C.sub.2H.sub.5O).sub.3SiCH(CH.sub.3)COOC.sub.3H.sub.7--n
(C.sub.2H.sub.5O).sub.3SiCH(CH.sub.3)COOC.sub.3H.sub.7--i
(C.sub.2H.sub.5O).sub.3SiCH(CH.sub.3)COOC.sub.4H.sub.9--n
(C.sub.2H.sub.5O).sub.3SiCH(CH.sub.3)COOC.sub.4H.sub.9--i
(C.sub.2H.sub.5O).sub.3SiCH(CH.sub.3)COOC.sub.4H.sub.9--t
[0080] The component (E) may be incorporated in the composition in
an amount of 0.5 to 15 parts by weight, preferably 1 to 10 parts by
weight, per 100 parts by weight of the component (D). With a less
amount of the component (E) than the aforesaid lower limit, the
effect on the component (D) may not be sufficient to achieve the
present purpose. A composition comprising a larger amount of the
component (E) than the aforesaid upper limit may not be cured
properly, so that physical strength of a cured product therefrom
may be too low.
[0081] The alkoxysilane (E) is mixed with the linear polyfluoro
compound (A) and the hydrophobic silica powder (D) in a mixing
apparatus such as a planetary mixer, a gate mixer and a kneader. By
mixing these three components all together, moisture adsorbed on a
surface of the hydrophobic silica powder (D) may be removed; a
surface of the hydrophobic silica powder (D) may be
alkoxysilylated; and adsorption of the linear polyfluoro compound
(A) on the surface of the hydrophobic silica powder (D) is promoted
to prevent adsorption of the component (F) on the surface of the
hydrophobic silica powder (D). Consequently, a flow property of the
composition, adhesion property in a curing process and durability
of a cured product therefrom are improved.
[0082] Preferred alkoxysilane (E) are as shown below. They are easy
to prepare and their by-products are volatile and thus easy to
remove.
(CH.sub.3O).sub.4Si
(C.sub.2H.sub.5O).sub.4Si
(CH.sub.3O).sub.3SiCH.sub.2COOCH.sub.3
(CH.sub.3O).sub.3SiCH.sub.2COOC.sub.2H.sub.5
(CH.sub.3O).sub.3SiCH.sub.2COOCH.sub.3
(CH.sub.3O).sub.3SiCH.sub.2COOC.sub.2H.sub.5
(CH.sub.3O).sub.3SiCH(CH.sub.3)COOCH.sub.3
(CH.sub.3O).sub.3SiCH(CH.sub.3)COOC.sub.2H.sub.5
(C.sub.2H.sub.5O).sub.3SiCH(CH.sub.3)COOCH.sub.3
(C.sub.2H.sub.5O).sub.3SiCH(CH.sub.3)COOC.sub.2H.sub.5
[0083] (F) Organosiloxane
[0084] The organosiloxane (F) makes the present composition
self-adhesive, i.e., adhering to a various kinds of substrates
without a primer. The organosiloxane (F) has a SiH bond and at
least one group selected from the group consisting of an epoxy and
trialkoxysilyl groups, which at least one group is bonded to a
silicon atom of the organosiloxane (F) via an organic group which
may contain an oxygen atom. Preferably, it further has at least one
perfloroalkyl group or perfloroxyalkyl group bonded to a silicon
atom of said organosiloxane via an organic group which may contain
an oxygen atom.
[0085] The organosiloxane (F) may be linear, cyclic or branched.
Examples of the organosiloxane (F) are as shown below. 17
[0086] wherein R.sup.4 is a monovalent hydrocarbon group which may
be halogenated, A and B will be explained below, and x, y, z and w
are numbers with 0.ltoreq.w.ltoreq.100, 1.ltoreq.x.ltoreq.100,
1.ltoreq.y.ltoreq.100, and 0.ltoreq.z.ltoreq.100 and.
[0087] Preferred examples of R.sup.4 include monovalent hydrocarbon
groups, having 1 to 10, particularly 1 to 8, carbon atoms, for
example, alkyl groups such as methyl, ethyl, propyl, butyl, hexyl,
cyclohexyl, and octyl groups; aryl groups such as pheyl, and tolyl
groups; aralykyl groups such as benzyl and phenylethyl groups; and
partly or fully halogenated groups thereof, among which a methyl
group is particularly preferred.
[0088] Preferably, x, y, z and w are numbers with
1.ltoreq.x.ltoreq.20, 1.ltoreq.y.ltoreq.20, 1.ltoreq.z.ltoreq.20,
0.ltoreq.w.ltoreq.20 with 3.ltoreq.w+x+y+z.ltoreq.50.
[0089] The group, A, is an epoxy or trialkoxysilyl group which is
bonded to a silicon atom of the organosiloxane (F) via an organic
group which may contain an oxygen atom. Examples are represented by
the following fomulae. 18
[0090] wherein R.sup.5 represents a divalent hydrocarbon group
having 1 to 10, particularly 1 to 5, carbon atoms, which may have
an oxygen atom, for example, an alkylene group such as a propylene,
a butylene, a pentylene, a hexylene, a propyleneoxymethylene, and a
butyleneoxymethylene group and a cycloalkylene group;
--R.sup.6--Si(OR.sup.7).sub.3
[0091] wherein R.sup.6 represents a divalent hydrocarbon group
having 1 to 10, particularly 1 to 4, carbon atoms, for example, an
alkylene group such as an ethylene, propylene and butylene group;
and R.sup.7 represents a monovalent hydrocarbon group having 1 to
8, particularly 1 to 4, carbon atoms, for example, an alkyl group
such as a methyl, ethyl, propyl, isobutyl and tert-butyl group; and
19
[0092] wherein R.sup.8 represents a monovalent hydrocarbon group
having 1 to 8, particularly 1 to 4, carbon atoms, for example, an
alkyl group such as a methyl, ethyl, propyl, isopropyl, butyl,
isobutyl and tert-butyl group; R.sup.9 represents a hydrogen atom
or a methyl group; and k is an integer of from 2 to 10.
[0093] The group, B, is a perfluoroalkyl group or a
perfluoroxyalkyl group bonded to a silicon atom of the component
(F) via an organic group which may have an oxygen atom. Examples of
B are represented by the following formulae
C.sub.gF.sub.2g+1--
[0094] wherein g is an integer as defined above; and
F--[CF(CF.sub.3)CF.sub.2O].sub.f--C.sub.hF.sub.2h--
[0095] wherein f and h are as defined above.
[0096] The organosiloxane (F) may be prepared by subjecting an
organohydrogenpoilysiloxane having at least three SiH bonds per
molecule to an addition reaction with a compound having both an
aliphatic unsaturated group such as a vinyl group or an allyl
group, and an epoxy group and/or a trialkokysilyl group and,
optionally, a compound having both an aliphatic unsaturated group
and a perfluoroalkyl group or perfluorooxyalkyl group, according to
a conventional manner. It should be noted that the number of the
aliphatic unsaturated group should be smaller than that of the SiH
bonds and therefore a part of the SiH bonds remain unreacted.
[0097] After the reaction, the organosiloxane (F) is isolated.
However, removal of unreacted reactants and a catalyst used may be
enough to be incorporated in the present composition.
[0098] Examples of the component (F) are as shown below, wherein Me
represents a methyl group. These may be used alone or in a mixture
of two or more of them. 2021
[0099] wherein o, q, and r are positive numbers, and p is an
integer of at least 0; 222324
[0100] wherein o, q, and r are positive numbers, and p is an
integer of at least 0. 25
[0101] The component (F) may be incorporated in the composition in
an amount of from 0.1 to 10, preferably 0.2 to 5, parts by weight
per 100 parts by weight of the component (A). With the component
(F) less than the aforesaid lower limit, satisfactory adhesion
strength is not be attained. A composition comprising the component
(F) in an amount more than the aforesaid upper limit may not flow
properly and the curing reaction is so prohibited that a cured
product shows a lower physical strength.
[0102] Optional Components
[0103] The present composition may comprise optional components in
addition to the aforesaid components (A) to (F), such as agents for
regulating the viscosity, flexibilizers, plasticizers,
hydrosilylation reaction retarders, inorganic fillers, adhesion
promoters, adhesion aids different from the component (F), and
silane coupling agents in such amounts as not to adversely affect
the present composition. An example of the agent for regulating the
viscosity or the flexibilizer is represented by the following
formula (8)
R.sub.f.sup.2--(X').sub.aCH.dbd.CH.sub.2 (8)
[0104] wherein, X' and "a" are as defined above and R.sub.f.sup.2
is represented by the following formula
F--[CF(CF.sub.3)CF.sub.2O].sub.f--C.sub.hF.sub.2h--
[0105] wherein f and h are integers as defined above, provided that
f is smaller than both an average of a sum, b+c, and an average of
a sum, u+v, in the group, R.sub.f.sup.1.
[0106] Examples of the polyfluoro monoalkenyl compound of the
formula (8) are as shown below. 26
[0107] wherein m is a number to meet the aforesaid
requirements.
[0108] Examples of the plasticizer are represented by the following
formulae (9) and (10):
D--O--(CF.sub.2CF.sub.2CF.sub.2O).sub.c'--D (9)
[0109] wherein D is a group of the formula CsF.sub.2.+.sub.1--with
s being an integer of from 1 to 3, c' is an integer of from 1 to
200 and not larger than a sum of an average of (b+c) and L and a
sum of an average of u+v in R.sub.f.sup.1 in the component (A);
D--O--(CF.sub.2O).sub.d'(CF.sub.2CF.sub.2O).sub.e'--D (10)
[0110] wherein D is the group as defined above, d' and e' are
integers of from 1 to 200 with d'+e'.ltoreq.(the average of b+c)+L
and d'+e'.ltoreq.u+v in R.sub.f.sup.1 in the component (A).
[0111] Examples of the linear polyfluoro compound of the formulae
(9) and (10) are as shown below.
CF.sub.3O--(CF.sub.2CF.sub.2CF.sub.2O).sub.n--CF.sub.2CF.sub.3
CF.sub.3--[(OCF.sub.2CF.sub.2).sub.n(OCF.sub.2).sub.m]--O--CF.sub.3
[0112] wherein m and n are integers of from 1 to 200 and a sum,
m+n, meets the aforesaid requirements.
[0113] The aforesaid compounds (8) to (10) may be incorporated in
an amount of from 1 to 300, preferably 50 to 250, parts by weight
per 100 parts by weight of the component (A). Preferably, these
compounds have a viscosity ranging from 5 to 100,000 mPa.s at 23
degrees C.
[0114] Examples of the retarder for hydrosilylation reaction
include acetylenic alcoholes such as 1-ethynyl-1-cyclohexano,
3-methyl-1-butyne-3-ol, 3,5-dimethyl-1-hexyne-3-ol,
3-methyl-1-pentyne-3-ol, and phenylbutynol; reaction products of
these acetylenic alcohols with chlorosilane substituted with a
monovalent fluorine-containing substituent,
3-methyl-3-pentene-1-yene, 3,5-dimethyl-3-hexyene-1-yene, and
triarylisocyanurate, a polyvinylsiloxane and organic phosphorus
compounds. By using the retardar, curing reactivity and a shelf
life of the composition can be controlled.
[0115] Examples of the inorganic fillers include reinforcing or
semi-reinforcing fillers such as silica powder, fused silica
powder, diatomaceous earth, and calcium carbonate; inorganic
pigments such as titanium oxide, iron oxide, carbon black, and
cobalt aluminate; heat stabilizers such as titanium oxide, iron
oxide, carbon black, cerium oxide, cerium hydroxide, zinc
carbonate, magnesium carbonate and manganese carbonate; heat
conductive agents such as alumina, boron nitride, silicon carbide
and metal powders; and electrical conductive agents such as carbon
black, silver powder, and conductive zinc white.
[0116] Examples of the adhesion aid include carboxylic acid
anhydrides and titanate esters.
[0117] Method for the Preparation of the Composition
[0118] The present composition may be prepared by thoroughly mixing
the aforesaid components (A) to (F) and, if desired, optional
components in a mixing apparatus such as a planetary mixer, a gate
mixer and kneader and, if needed, a three-roll mill.
[0119] In the mixing, not all of the components are mixed at a
time. In a first step, a part of the component (A), component (D)
and component (E) are mixed, wherein the component (D) is added,
preferably in several portions, in an amount of 20 to 60 parts by
weight per 100 parts by weight of the component (A) now mixed while
mixing. The component (E) is added in an amount of from 0.5 to 15
parts by weight per 100 parts by weight of the component (D). The
mixing is first carried out without heating until the hydrophobic
silica (D) gets thoroughly wet with the other components. In a
second step, the mixture obtained in the first step is kneaded with
heating under a reduced pressure or heating under pressure, and
then the rest of the component (A) is added. In a third step, the
remaining components are added to the liquid base compound obtained
in the second step and thoroughly mixed until a homogeneous mixture
is obtained.
[0120] In the first and second steps, a surface of the hydrophobic
silica powder (D) becomes free of any adsorbed water, treated with
the alkoxysilane (E) and coated with the linear polyfluoro compound
(A) to prevent the other component, particularly the component (F),
from adsorbing on the surface of the hydrophobic silica (D),
whereby a flow property of the composition and adhesion strength
are improved. The kneading may be carried out in a planetary mixer,
a gate mixer and kneader.
[0121] In the first step, the amount of the component (D) to be
added to 100 parts by weight of the component (A) varies depending
on the type of the hydrophobic silica powder (D) as well as the
amount and the type of the alkokysilane (E). Typically, the amount
ranges from 20 to 60 parts by weight. If the amount is less than
the aforesaid lower limit, a shearing force is too small to
sufficiently wet the component (D) with the component (A), so that
the viscosity of the resulting composition may too high. If the
amount exceeds the aforesaid upper limit, so much heat generates
during mixing that may damage a mixing apparatus.
[0122] Heating conditions in the second step are not particularly
limited, but preferably heating at a temperature of from 120 to 180
degrees C. for at least 1 hour is employed.
[0123] A pressure in the second step may be above or below
atmospheric pressured depending on a mixing apparatus used. In a
planetary mixer or a gate mixer, a reduced pressure of -0.05 MPa in
gage or lower is preferably employed. In a kneader, a gage pressure
of 0.4 to 0.6 MPa is preferably employed. Under these conditions,
the component (A) easily wets a surface of the component (D) to
coat the surface.
[0124] In the third step, the present adhesive composition is
obtained by adding the components (B), (C) and (F) to the liquid
base compound containing the component (A), the component (D)
coated with the component (A) and/or with the component (E).
[0125] The adhesive composition thus prepared may be cured at room
temperature depending on the type of the functional groups in the
linear polyfluoro compound (A) and the type of the platinum group
metal compound (C). Preferably, heat is applied to promote the
curing. To attain stronger adhesion to various substrates, it is
preferred to heat the composition at a temperature of 60 degrees C.
or higher, more preferably, 100 to 200 degrees C., for a period of
from several minutes to several hours.
[0126] The present composition may be used in a solution of a
desired concentration in a solvent, for example, a fluorinated
solvent such as 1,3-bis(trifluoromethyl)benzene, Fluorinert (trade
mark, ex 3M Co.), perfluorobutyl methyl ether, and perfluorobutyl
ethyl ether. The use of the solvent is particularly preferred for a
thin layer coating application.
[0127] The present adhesive composition is useful as an adhesive
for automobile parts, and electric and electronic parts. For
example, the present composition is useful as a sealant or
protective coating for pressure sensors, gas concentration
detectors, and temperature sensors used in automobile control
systems; protective encapsulant for sensors exposed to hot water,
various kinds of gases or chemicals; an adhesive for ink jet
printers; an adhesive or encapsulant for printer heads; a coating
agent for rolls or belts in laser printers or copying machines; and
a sealant or coating agent for printed circuit boards.
EXAMPLES
[0128] The present invention will be explained in detail below with
reference to the Examples, but not limited to them. In the
following, "part" means "part by weight." Viscosity and adhesion
strength were measured at 23 degrees C.
Example 1
[0129] In a planetary mixer, 100 parts of the linear polyfluoro
compound of the following formula (11) having a viscosity of 10,000
mPa.s, a number average molecular weight of 17,000 and a vinyl
group content of 0.012 mole/100 g were placed, to which 2.0 parts
of alkoxysilane of the following formula (12). Then, 25 parts of
fumed silica was added in five batches in 2 hours while kneading
without heating, which silica had been surface treated with
dimethyldichlorosilane and had a BET specific surface area of 110
m.sup.2/g and a moisture content of 0.3 wt %. Then, the planetary
mixer was heated while mixing so that a temperature of the content
of the mixer rose to 150 degrees C. The content was kept at a
temperature of from 150 degrees C. to 170 degrees C. for further 2
hours under a reduced pressure of -0.008 MPa gage. Then, the
content was cooled below a temperature of 40 degrees C., to which
25 parts of the linear polyfluoro compound of the formula (11) was
added and mixed for another 1 hour. The contents thus obtained were
kneaded in a three-roller mill for 2 passes, whereby a base
compound was obtained.
[0130] Forty eight parts of the base compound and 60 parts of the
linear polyfluoro compound of the formula (11) having a molecular
weight of 18,600 and a vinyl group content of 0.000107 mole/100 g
were placed in the planetary mixer and mixed to a homogeneous
mixture to which the following components were added and thoroughly
mixed in the order described below: 0.2 part of a solution of
platinum complex with divinyltetramethyldisiloxane in toluene
having a platinum concentration of 0.5 wt %, 0.3 part of a 50%
solution of ethynyl cyclohexanol in toluene, 1.6 parts of the
organohydrogensiloxane of the following formula (13) having 0.00386
mole/g of SiH bond, 1.1 parts of the organohydrogensiloxane of the
following formula (14) having 0,00779 mole/g of SiH bond, 0.5 part
of the organosiloxane of the formula (15) having a epoxy group and
1.4 parts of the organosiloxane of the formula (16) having a epoxy
group. A ratio of a SiH bond/vinyl group in the compound of the
formula (11) was 2.3. By deaerating the mixture thus obtained, the
present composition was obtained. 27
[0131] Shear Adhesion Strength and Cohesive Failure
[0132] Two test pieces of 100 mm.times.25 mm made of one of the
materials shown in Table 1 were arranged lengthwise with a 10 mm
long end of each test piece overlapped mutually. Between the
overlapped parts, 1 mm thick layer of the composition prepared
above was applied and heated at 150 degrees C. for 1 hour to cure.
The test specimen thus obtained was subjected to measurement of
shear adhesion strength by cramping a free end of one of the test
pieces and pulling down a free end of the other test piece at a
pulling rate of 50 mm/min using a tensile tester. A force at break
the bond was measured as initial shear adhesion strength. Then, the
ends of the test pieces where the composition was applied were
visually observed to determine cohesive failure percentage as a
ratio of an area where the cured composition remained to the area
where the composition initially applied.
[0133] Resistance of the Cured Composition to Pressure, Heat or
Gasoline
[0134] Test specimens obtained in the same manner as described
above were subjected to the following tests conditions and then to
the measurements of shear adhesion strength and cohesive failure
percentage as described above.
[0135] Test A: Pressure cooker test at a temperature of 121 degrees
C., and a pressure of 2 atm for 50 hours;
[0136] Test B: Heat resistance test at 150 degrees C. for 1000
hours;
[0137] Test C: Gasoline resistance test by immersing a test
specimen in test fuel oil C at 25 degrees C. for 168 hours.
Example 2
[0138] The procedures in Example 1 were repeated, except that 25
parts of fused silica surface-treated with dimethyldichlorosilane
having a BET specific surface of 110 m.sup.2/g and a moisture
content of 0.4 wt % was used in place of the fused silica used in
Example 1 and 2.5 parts of alkoxysilane of the following formula
(17) was used in place of the alkoxysilane of the formula (12) used
in Example 1.
(CH.sub.3O).sub.3SiCH(CH.sub.3)COOC.sub.2H.sub.5 (17)
Example 3
[0139] The procedures in Example 1 were repeated, except that 25
parts of fused silica surface-treated with hexamethyldisilazane
having a BET specific surface of 120 m.sup.2/g and a moisture
content of 0.2 wt % was used in place of the fused silica used in
Example 1 and 1.5 parts of alkoxysilane of the following formula
(18) was used in place of the alkoxysilane of the formula (12) used
in Example 1.
(CH.sub.3O).sub.3SiCH(CH.sub.3)COOC.sub.8H.sub.17--n (18)
Comparative Example 1
[0140] The procedures in Example 1 were repeated except that the
alkoxysilane of the formula (12) was not used.
Comparative Example 2
[0141] The procedures in Example 2 were repeated except that the
alkoxysilane of the formula (17) was not used.
Comparative Example 3
[0142] The procedures in Example 3 were repeated except that the
alkoxysilane of the formula (18) was not used.
[0143] The tests results are as shown in the Table 1 wherein the
numerals described in parentheses are cohesion failure percentage
and "PBT" represents polybutylene terephthalate.
1 TABLE 1 Shear adhsion strength Examples Comparative examples
(MPa) 1 2 3 1 2 3 Initial Aluminum 2.5(100) 2.5(100) 2.3(100)
2.4(100) 2.2(90) 2.2(100) Stainless steel 2.1(100) 2.1(100)
2.0(100) 2.0(95) 1.9(90) 1.9(95) Alumina 2.4(100) 2.4(100) 2.3(100)
2.2(100) 2.1(90) 2.1(100) Epoxy resin 1.8(100) 1.7(100) 1.7(100)
1.6(90) 1.5(90) 1.6(95) PBT resin 2.0(100) 2.0(100) 1.9(100)
1.9(95) 1.8(90) 1.8(95) After Aluminum 2.5(100) 2.5(100) 2.3(100)
2.3(95) 2.2(90) 2.2(95) test Stainless steel 2.1(100) 2.1(100)
2.0(100) 1.9(90) 1.8(85) 1.8(90) conditions A Alumina 2.4(100)
2.4(100) 2.3(100) 2.3(95) 2.1(90) 2.1(95) Epoxy resin 1.6(100)
1.5(100) 1.5(100) 1.4(85) 1.2(80) 1.4(90) PBT resin 1.1(100)
1.1(100) 1.0(100) 1.0(90) 0.9(80) 0.9(95) After Aluminum 2.7(100)
2.7(100) 2.5(100) 2.6(100) 2.5(95) 2.4(100) test Stainless steel
2.3(100) 2.3(100) 2.2(100) 2.2(95) 2.0(90) 2.1(95) conditions B
Alumina 2.6(100) 2.6(100) 2.5(100) 2.4(95) 2.2(90) 2.3(100) Epoxy
resin 1.6(100) 1.5(100) 1.5(100) 1.4(90) 1.3(90) 1.4(95) PBT resin
1.8(100) 1.8(100) 1.7(100) 1.7(90) 1.6(85) 1.6(90) After Aluminum
2.2(100) 2.2(100) 2.1(100) 2.0(90) 1.9(85) 2.0(95) test Stainless
steel 1.8(100) 1.8(100) 1.8(100) 1.6(90) 1.5(85) 1.6(90) conditions
C Alumina 2.1(100) 2.1(100) 2.0(100) 2.0(95) 1.9(90) 1.9(95) Epoxy
resin 1.6(100) 1.5(100) 1.5(100) 1.4(85) 1.2(80) 1.4(90) PBT resin
1.8(100) 1.8(100) 1.7(100) 1.6(90) 1.5(85) 1.6(95)
[0144] As shown in Table 1, the present compositions showed almost
100% cohesive failure, indicating stronger adhesion to the
substrates than the compositions or the comparative examples. The
cured products obtained from the present compositions had higher
resistance than the compositions of the comparative examples. The
present composition is useful not only as an adhesive but also as
protective sealant and coating.
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