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...
Patent
1988-08-10
1990-02-20
Marquis, Melvyn I.
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...
524297, 524425, 524431, 524495, 524588, 524589, 524775, 524783, 524788, 524858, 525440, 525446, 525453, 525460, 528 28, 528 30, 528 60, 528 65, 528 66, 528 76, 528 77, C08K 509
Patent
active
049027360
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a one-part curing composition which cures in the humidity in the air, more particularly it relates to a one-part curing composition which comprises as essential constituents a compound having two or more silylthio ether bonds per molecule and a polymer having two or more isocyanate groups per molecule, which cures naturally in the humidity in the air, and which can be used as a sealing material.
BACKGROUND ART
Polymers having two or more isocyanate groups per molecule can readily polymerize by a reaction with an active hydrogen containing compound or water, and are widely used in fields such as sealing materials, caulking materials, adhesives, and paints. These isocyanate group-containing polymers are mixed with diamines, amino alcohols, glycols, polyols, etc. and are used as one-part or two-part curing compositions.
Of these, some one-part curing compositions cure in the humidity in the air by the curing mechanism of formula (1): ##STR2## (where R is a divalent organic group).
The carbon dioxide gas produced during the curing gives rise to swelling, foaming, and gas pockets. In particular, in a one-part curing composition with a fast curing speed, gas pockets easily occur inside the cured substance or near the interface between the cured substance and the object to which it adheres, having a detrimental effect on the sealing effect and strength and the adhesion to the object. Further, there is the problem that when the cured substance is heated, foaming, and softening or embrittlement of the cured substance occurs.
To resolve these problems, various proposals have been made in the past. For example, Japanese Examined Pat. Publication (Kokoku) No. 44-2114 discloses the addition of calcium oxide to the composition so as to absorb the carbon dioxide gas produced during curing. Further, Japanese Unexamined Pat. Publication (Kokai) No. 52-17560 discloses the use of a reaction of polyalkylene ether diol and polyalkylene triol with an excess of diisocyanate polymer having equivalent isocyanate groups and the use of a polymer which blocks the remaining isocyanate groups to suppress the foaming due to carbon dioxide gas so as to provide a one-part curing composition with a fast curing no speed. Further, German Pat. No. 2,116,882, No. 2,521,841, No. 2,651,479, and No. 2,718,393 disclose methods for curing without generation of carbon dioxide gas by the addition of enamine or compounds containing an enamine group, an alidimine group, or a ketimine group.
However, the method disclosed in Japanese Examined Pat. Publication (Kokoku) No. 44-2114 suffers from the problem that the generation of carbon dioxide gas under high temperature and humidity conditions exceeds the absorption by the calcium oxide and thus it is difficult to completely prevent foaming due to the carbon dioxide gas. Further, the method disclosed in Japanese Unexamined Pat. Publication (kokai) No. 52-17560 has the defect that foaming occurs under high temperature and humidity conditions and further that the usable isocyanate containing polymers are limited. Further, in the methods disclosed in German Pat. No. 2,116,882, No. 2,521,841, No. 2,651,479, No. 2,718,393, the active hydrogen-containing compounds used are limited to amines and the curing speed is slow. Further, the softening or embrittlement of the cured substance upon high temperature heating is considered to derive from the urethane bonds or urea bonds in the cured substance and, in the case of the use of polyamines or polyols as curing agents, improvement is difficult.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a one-part curing composition which avoids foaming due to carbon dioxide gas, and the problems in conventional one-part curing compositions using isocyanate-containing polymers as basic components, and enables curing by a curing mechanism free from generation of carbon dioxide gas.
Another object of the present invention is to provide a one-part curing composition free from foaming under high tem
REFERENCES:
patent: 4698407 (1987-10-01), Nakagima et al.
Dokoshi Noriaki
Matsui Tatsuro
Nakajima Masashi
Nonaka Toshiaki
Marquis Melvyn I.
Toray Thiokol Company Limited
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