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...
Reexamination Certificate
2001-11-07
2004-08-17
Robertson, Jeffrey B. (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...
C528S015000, C528S025000, C156S329000
Reexamination Certificate
active
06777485
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a novel sealant composition containing a reinforcing filler and a method of equipping a vehicle with glass by direct glazing with the composition.
BACKGROUND ART
The glass for fixed. windows, such as the windshield and rear-window of a vehicle, is installed on the automotive body more often than not by the method called “direct glazing”. Direct glazing is a method of equipping automotive bodies with glass directly using a sealant having a high adhesive strength (which may be called an “adhesive” as well).
The sealant used for such direct glazing for vehicles is required to have the following characteristics.
(1) The sealant itself must have a high mechanical strength so that it will not be easily destroyed, namely a tensile strength at break of not less than 3 MPa;
(2) A high adhesive strength can be established between the glass and the sealant or between the automotive body and the sealant;
(3) The sealant must have an adequate degree of hardness and yet a sufficient degree of rubber elasticity to preclude the transmission of vibrations and shocks to the glass, namely a 100% modulus of not less than 1 MPa and an elongation at break of not less than 200%;
(4) For quick glazing, the sealant must cure quickly after the glass is set in position on the body, specifically undergoing surface curing in about 10 to 55 minutes of standing in the air at room temperature;
(5) For early expression of physical properties after installation, the depth curing of the sealant should be rapid; the sealant should specifically cure down to not less than 4 mm from the surface in one day.
Today, as the sealant for direct glazing, moisture-curable urethane sealants are in use and no sealant that may replace them has been commercially developed as yet.
Aside from urethane sealants, a curable resin composition comprising a crosslinkable silyl group-containing oxyalkylene polymer, carbon black and a crosslinkable group-free oxyalkylenenpolymer has been disclosed (WO 97/13820). However, this literature does not teach the proper introduction rate of a crosslinkable silyl group in the crosslinkable silyl group-containing oxyalkylene polymer or the adhesive strength of the composition.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a novel sealant that may replace the urethane sealant and a direct glazing method using the novel sealant. Stated differently, the invention relates to a novel curable resin composition providing for sufficiently high mechanical strength, adhesive strength, rubber elasticity and good workability and a direct glazing method utilizing the composition.
As such, the first aspect of the invention is concerned with a curable resin composition
which comprises
(I) a reactive silicon group-containing polyether oligomer such that the reactive silicon group exists exclusively at the molecular chain terminus and that the introduction rate of the reactive silicon group into the molecular chain terminus is not less than 85% as determined by
1
H-NMR analysis
and (II) a reinforcing filler.
The second aspect of the invention is concerned with a direct glazing method for directly equipping a vehicle with glass using a sealant,
wherein said curable resin composition is used as said sealant.
The present invention is now described in detail.
DISCLOSURE OF THE INVENTION
The reactive silicon group-containing polyether oligomer (I) for use in the curable resin composition of the present invention should be such that the reactive silicon group exists exclusively at the molecular chain terminus and that the introduction rate of the reactive silicon group is not less than 85% as determined by
1
H-NMR analysis.
The term “reactive silicon group” in the context of the present invention means any group capable of forming a siloxane bond upon inter-group condensation and, as such, is not particularly restricted. However, the group represented by the following general formula (1) can be mentioned as a preferred example.
—(Si(R
1
2-b
)(X
b
)O)
m
Si(R
2
3-a
)X
a
(1)
(wherein R
1
and R
2
may be the same or different and each represents an alkyl group containing 1 to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, an aralkyl group containing 7 to 20 carbon atoms or a triorganosiloxy group of the formula (R′)
3
SiO—; when two or more R
1
or R
2
groups are present, they may be the same or different; R′ represents a monovalent hydrocarbon group containing 1 to 20 carbon atoms and the three R′ groups may be the same or different; X represents a hydroxyl group or a hydrolyzable group and when two or more X groups are present, they may be the same or different; a represents 0, 1, 2 or 3 and b represents 0, 1 or 2; as regards b in —Si(R
1
2-b
)(X
b
)O— which occurs in m repeats, the value of b may be the same or different over the repeats; m represents an integer of 0 to 19; with the condition that the relation of a +&Sgr;b≧1 is satisfied).
Referring to the above general formula (1), R
1
and R
2
each may be an alkyl group such as methyl and ethyl; a cycloalkyl group such as cyclohexyl; an Aryl group such as phenyl; an aralkyl group such as benzyl; or a triorganosiloxy group represented by the formula (R′)
3
SiO— wherein R′ is methyl or phenyl, for instance. Particularly preferred for R
1
, R
2
and R′ are methyl.
The hydrolyzable group mentioned above for X is not particularly restricted but can be a known hydrolyzable group. Thus, for example, hydrogen, halogen, alkoxy, acyloxy, ketoximate, amino, amido, acid amido, aminoxy, mercapto and alkenyloxy can be mentioned. In view of mild hydrolyzability and ease of handling, alkoxy groups such as methoxy, ethoxy, propoxy and isopropoxy are preferred.
The hydroxyl group and/or hydrolyzable group may be attached, in a varying number of 1 to 3, to one silicon atom but the (a +&Sgr;b) value, namely the total number of hydroxyl and hydrolyzable groups occurring per reactive silicon group is preferably in the range of 1 to 5. When two or more hydroxyl and/or hydrolyzable groups exist in the reactive silicon group, they may be the same or different.
The number of silicon atoms in the reactive silicon group may be one or not less than two but, in the case of the reactive silicon group in which silicon atoms are linked by siloxane bonding or the like, may be about 20 at the maximum.
Among various reactive silicon groups, those of the following general formula (8) are preferred from availability points of view.
—Si(R
2
3-a
)X
a
(8)
(wherein R
2
, X and a are as defined above)
The introduction rate of such a reactive silicon group may be determined by various techniques but, in the context of the present invention, is the value found by
1
H-NMR analysis of the reactive silicon group-containing polyether oligomer (1) The introduction rate of the reactive silicon group can be defined as the value found by determining the proportions of the termini into which the reactive silicon group has been introduced and the molecular chain termini into which the reactive silicon group has not been introduced from
1
H-NMR data and calculating the percentage of the termini into which the reactive silicon group has been introduced based on the total population of molecular chain termini.
In the reactive silicon group-containing polyether oligomer to be used in the present invention, the introduction rate of the reactive silicon group into the molecular chain terminus as determined by
1
H-NMR analysis is not less than 85% and, to provide for further improvements in physical properties, is preferably not less than 90%.
The curable resin composition comprising a reactive silicon group-containing polyether oligomer with a terminal introduction rate of the reactive silicon group of not less than 85% not only insures good physical properties required of a sealant (tensile strength at break, elongation at break, cure speed, etc.) but also displays an outstanding adhesive strength. When said introduction rate is less than 85%, the effec
Ito Hiroshi
Iwakiri Hiroshi
Jyono Hideharu
Kawakubo Fumio
Odaka Hidetoshi
Kaneka Corporation
Robertson Jeffrey B.
Westerman Hattori Daniels & Adrian LLP
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