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
2000-11-22
2004-03-09
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...
C524S115000, C524S284000, C524S300000, C524S306000, C524S464000, C524S487000, C528S018000, C528S027000, C528S034000
Reexamination Certificate
active
06703442
ABSTRACT:
TECHNICAL FIELD
This invention relates to a two-pack type curable composition containing a curable organic polymer having in its molecule a functional group crosslinkable by a reaction catalyzed by a bivalent tin based curing catalyst.
BACKGROUND ART
Examples of known compositions comprising a curable organic polymer having in its molecule a functional group crosslinkable by a reaction catalyzed by a bivalent tin based curing catalyst include an organic polymer which has a silicon-containing group (may be referred to as reactive silicon group hereinafter) having a hydroxyl group and/or hydrolyzable group bonded to a silicon atom and crosslinkable by forming a siloxane bond, an organic polymer which has an isocyanate group and a composition comprised of a hydroxyl group-containing organic polymer and a polyisocyanate compound. Particularly, an organic polymer having its bone structure comprised of such as of polyoxyalkylene or polyisobutylene is already produced industrially and used in various curable compositions.
Among them, polyoxyalkylene based polymers and polyisobutylene based polymer having reactive silicon groups are disclosed for example in JP-A-52-73998, JP-A-5-125272, JP-A-63-6003, JP-A-63-6041, JP-A-1-38407 and JP-A-8-231758 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”), and, like the case of room temperature-curable silicon rubber, they harden and give rubber-like hardened products at room temperature by forming a siloxane bond (Si—O—Si) between polymers by the action of moisture in the air or water in a composition.
A polyoxyalkylene based polymer having isocyanate group also hardens and gives a rubber-like hardened product at room temperature by forming a urea bond or urethane bond between polymers by the action of moisture in the air or the like. In addition, a composition comprised of a polyoxyalkylene based polymer having hydroxyl group and a polyisocyanate compound also hardens and gives a rubber-like hardened product by forming a urea bond or urethane bond between polymers by a reaction generated by mixing of these components.
It is known that the crosslinking reaction of these polymers is considerably accelerated by the presence of a tin compound, and, making use of this characteristic, they are broadly used in sealants, adhesives, paints and the like applications as a two-pack type curable composition by dividing a curable organic polymer having in its molecule a crosslinkable functional group and a catalyst component into solution A and solution B.
Various characteristics are required for the curable compositions to be used in sealants, adhesives and the like and the rubber-like hardened products obtained by their hardening and, in addition to modulus, breaking elongation, breaking strength and the like mechanical properties, recovery and adhesiveness for substrate are particularly important characteristics which have therefore been extensively studied. As a result, it is known that the modulus, breaking elongation, breaking strength and the like mechanical properties suitable for sealing materials can be obtained by adding a phthalic acid ester or the like plasticizer to a curable composition. It is known also that the recovery can be improved by the use of a bivalent tin based curing catalyst in comparison with the use of a tetravalent tin based catalyst. In addition, when made into a two-pack type curable composition, it is broadly carried out to control volume and viscosity of a curing agent as a component of the curing catalyst-containing counter part by adding a plasticizer, filler or the like, for the sake of its easy weighing and dispersion at the time of its mixing with the base resin. On the other hand, it has been discovered by the present inventors that markedly excellent adhesiveness, particularly adhesiveness for mortar slabs, is generated by the joint use of an amino group-containing silane compound as a compound which has both of an amino group and a hydrolyzable silyl group in its molecule, an epoxy group-containing silane compound as a compound which has both of an epoxy group and a hydrolyzable silyl group in its molecule and an epoxy resin as an adhesiveness provider.
However, when the present inventors have examined a curable composition comprised of an amino group-containing silane compound, an epoxy group-containing silane compound, an epoxy resin, a bivalent tin based curing catalyst as the curing catalyst and a plasticizer, in order to obtain a curable composition which satisfies all of the mechanical properties, recovery and adhesiveness for substrate, based on known techniques and the above discovery, it was revealed that this composition has a serial problem of being poor in storage stability. That is, reduction of adhesiveness was found after storage of the one-pack type composition containing all components. This is considered to be due to a reaction of the epoxy groups of the epoxy group-containing silane compound and epoxy resin with the amino group of the amino group-containing silane compound. In consequence, an attempt was made to prepare a two-pack type curable composition by dividing it into solution A and solution B in order to avoid coexistence of the amino group-containing silane compound with the epoxy group-containing silane compound and epoxy resin, but, in this two-pack type curable composition which respectively contains a curable organic polymer crosslinkable in the presence of a bivalent tin curing catalyst and having in its molecule a functional group crosslinkable by a reaction and an amino group-containing silane compound as the solution A components, and, an epoxy group-containing silane compound, an epoxy resin, a curing catalyst and a plasticizer for viscosity controlling use as the solution B components, its use became difficult because of the increase in viscosity during its storage, which seemed to be due to a catalytic reaction of water in the solution A with the amino group.
Accordingly, the object of the invention is to provide a curing agent for two-pack type curable composition use having excellent storage stability and also a two-pack type curable composition which satisfies all of the mechanical properties, recovery and adhesiveness for substrate, can be easily mixed when used and has excellent storage stability.
DISCLOSURE OF THE INVENTION
With the aim of solving the above problems, the present inventors have conducted intensive studies and found as a result of the efforts that the activity reduction and deactivation of curing catalysts, which have generally been considered to be due to adsorption and degeneration of catalyst species caused by added inorganic fillers, were actually caused by a completely different phenomenon, thus resulting in the resolution of the above problems.
Illustratively, in the case of a two-pack type curable composition which respectively contains a curable organic polymer, an epoxy group-containing silane compound and an epoxy resin as the solution A components and an amino group-containing silane compound, a curing catalyst and a plasticizer for viscosity controlling use as the solution B components, it was revealed that catalytic activity of the curing agent is considerably reduced after its storage and the curing rate is sharply reduced. In addition, a new surprising fact was discovered that reduction of the catalytic activity is not observed in the coexistence of a phthalic ester based plasticizer and a bivalent tin based curing catalyst, or in the coexistence of an amino group-containing silane compound, epoxy group-containing silane compound or the like compound containing a hydrolyzable silyl group in its molecule (to be referred also to as hydrolyzable silyl group-containing compound hereinafter) and a bivalent tin based curing catalyst, independent of the presence or absence of inorganic fillers, but activity of the bivalent tin based curing catalyst (c) is lost in the coexistence of the phthalic ester based plasticizer, hydrolyzable silyl group-containing compound and bivalent tin based curing catalyst (c),
Ando Hiroshi
Fukunaga Atsushi
Kawakubo Fumio
Masaoka Yoshiteru
Armstrong Kratz Quintos Hanson & Brooks, LLP
Dawson Robert
Kaneka Corporation
Zimmer Marc
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