Curable composition

Details Curable composition Curable composition

2000-06-14

2002-11-26

Moore, Margaret G. (Department: 1712)

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

Synthetic resins

From silicon reactant having at least one...

C528S026000, C528S034000, C525S100000

Reexamination Certificate

active

06486289

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a curable composition which is conducive to reducing a tensile stress with a high restoring force retained and has a sufficiently high degree of adhesiveness.
BACKGROUND ART
Polymers containing reactive silicon groups cure by crosslinking in the presence of moisture. A curable composition utilizing a polymer the backbone chain of which is a polyoxypropylene, among them, has the characteristic of being liquid at room temperature but forming a rubber elastomer on curing and has, therefore, been used universally as, for example, a sealant for architectural use.
For use in architectural applications, a curable composition is required to be of high restoring force and low stress in order to follow the shrinkage of joints.
As means for implementing a low stress feature, a method, comprising changing polymer species and that comprising increasing the amount of the curing catalyst, and the like are known. However, with any of such means, a reduction in stress is accompanied by a decrease in restoring force so that a curable composition having a satisfactory balance of stress and restoring force cannot be obtained.
Moreover, in order that such a composition can be used as a sealant, the composition is further required to have satisfactory adhesive properties. For the construction of a cured product of the sealant, a tin-series curing catalyst or an amine-series promotor is usually employed. However, the concomitant use of an amine compound causes the problem of lowering adhesiveness and is, therefore, not recommendable for sealant use.
DISCLOSURE OF THE INVENTION
The present invention is directed to a curable composition comprising an oxyalkylene polymer (A-1) having at least one reactive silicon group per molecule, an acid (B), an amine (C), and a tin-series curing catalyst (D).
The invention is now described in detail.
The present invention comprises an oxyalkylene polymer (A-1), an acid (B), an amine (C) and a tin-series curing catalyst (D).
The component (A-1) mentioned above contains at least one reactive silicon group per polymer molecule. If the number of reactive silicon groups per molecule is less than 1, the polymer will be insufficient in curability, and, therefore, the above range must be adhered to. The preferred number is 1.1 to 5. Exceeding 5 is undesirable, for the network structure will become too dense to show satisfactory mechanical characteristics.
The backbone chain of said oxyalkylene polymer (A-1) having at least one reactive silicon group per molecule has a repeating unit of the following general formula (1).
—R
1
—O—  (1)
(wherein R
1
represents a divalent hydrocarbon group)
R
1
mentioned above is not particularly restricted insofar as it is a divalent hydrocarbon group but is preferably a methylene group or a straight-chain or branched-chain alkylene group containing2 to 14 carbonatoms. The more preferred group is a straight-chain or branched-chain alkylene group of 2 to 4 carbon atoms.
The repeating unit of the general formula (1) mentioned above is not particularly restricted, but there can be mentioned —CH
2
O—, —CH
2
CH
2
O—, —CH
2
CH (CH
3
)O—, —CH
2
CH (C
2
H
5
)O—, —CH
2
C(CH
3
)
2
O—, and —CH
2
CH
2
CH
2
CH
2
O—, among others.
The backbone chain of said oxyalkylene polymer (A-1) may comprise one species of said repeating unit represented by general formula (1) or comprise two or more species of said repeating units.
Said backbone chain of oxyalkylene polymer (A-1) may contain urethane-binding and/or other moieties within the range not seriously affecting the characteristics of the oxyalkylene polymer.
The urethane-binding moiety mentioned above are not particularly restricted, but there can be mentioned the moiety available from the reaction of an aromatic polyisocyanate, e.g. toluene(tolylene) diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate or the like, or an aliphatic polyisocyanate, e.g. isophorone diisocyanate, hexamethylene diisocyanate or the like, with a polyol having the above repeating unit of the general formula (1).
The reactive silicon group in said component (A-1) is a silicon-containing group having a hydrolyzable group or a hydroxyl group as the reactive group and is preferably a group of the following general formula (2).
—[Si(R
2
)
2−a
(X)
a
O]
m
—Si(R
3
)
3−b
(X)
b
  (2)
wherein R
2
and R
3
are the same or different and each represents an alkyl group of 1 to 20 carbon atoms, an aryl group of 6 to 20 carbon atoms, an aralkyl group of 7 to 20 carbon atoms or a triorganosiloxy group of the formula (R
4
)
3
SiO— in which R
4
represents a monovalent hydrocarbon group of 1 to 20 carbon atoms and the three R
4
groups may be the same or different; when R
2
or R exists in 2 or more, each may represent the same group or different groups; X represents a hydrolyzable group or a hydroxyl group and when X exists in 2 or more, each may represent the same group or different groups; a represents an integer of 0 to 2; b represents an integer of 0 to 3; m represents an integer of 0 to 19 and when m exists in 2 or more, a in m of the—[Si (R
2
)
2−a
(X)
a
O]
m
— group may represent the same value or different values. It should be understood that said reactive silicon group of the general formula (2) contains at least one hydrolyzable group or hydroxyl group represented by X.
The above-mentioned alkyl group of 1 to 20 carbon atoms is not particularly restricted, but there can be mentioned methyl, ethyl, isopropyl, butyl, t-butyl and cyclohexyl, among others.
The aryl group of 6 to 20 carbon atoms is not particularly restricted but may for example be phenyl or naphthyl.
The aralkyl group of 7 to 20 carbon atoms is not particularly restricted but may for example be benzyl.
The monovalent hydrocarbon group of 1 to 20 carbon atoms is not particularly restricted, but there can be mentioned methyl, ethyl, isopropyl, butyl, t-butyl, pentyl, ethinyl, 1-propenyl, vinyl allyl, 1-methylbutyl, 2-ethylbutyl and phenyl, among others.
Said hydrolyzable group represented by X is not particularly restricted, but there can be mentioned various known groups such as hydrogen, halogen, alkoxy, acyloxy, ketoximate, amino, amido, acid amide, aminooxy, mercapto, alkenyloxy, etc. Among these, hydrogen, alkoxy, acyloxy, ketoximate, amino, amido, aminooxy, mercapto and alkenyloxy are preferred, and from the standpoint of mild hydrolyzability and ease of handling, alkoxy groups are particularly preferred.
The hydroxyl or hydrolyzable group represented by X can bind, within the range of 1 to 3, to one silicon atom. Moreover, the sum of the hydroxyl and hydrolyzable groups in said reactive silicon group of the general formula (2) is preferably within the range of 1 to 5.
The silicon atom forming said reactive silicon group may be one or two or more, and when silicon atoms are joined by siloxane bonding or the like, the number may be 20 at a maximum.
Among reactive silicon groups represented by the above general formula (2), reactive silicon groups of the following general formula (3) are readily available and, therefore, can be used with advantage in the practice of the present invention.
—Si(R
3
)
3−b
X
b
  (3)
(wherein R
3
, X, and b are as defined hereinbefore).
Referring to said component (A-1), the method for introduction of said reactive silicon group of the general formula (2) is not particularly restricted but any of the known methods, such as the following, can be utilized.
(1) The process comprising reacting an oxyalkylene polymer having a functional group such as hydroxyl within its molecule with an organic compound having an active group reactive to said functional group and an unsaturated group to thereby give an unsaturated group-containing oxyalkylene polymer or carrying out a copolymerization reaction with an epoxy compound containing an unsaturated group to thereby give an unsaturated group-containing oxyalkylene polymer and then hydrosilylating the resulting unsaturated group-containing oxyalkylene polymer with a reactive

Affiliated with

Also associated with

Rating

Curable composition does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Curable composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Curable composition will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2939264