Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From reactant having at least one -n=c=x group as well as...
Reexamination Certificate
2000-08-04
2003-11-18
Sergent, Rabon (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From reactant having at least one -n=c=x group as well as...
C521S155000, C521S159000, C521S163000, C521S170000, C528S068000, C528S074000, C528S076000, C528S080000, C528S085000
Reexamination Certificate
active
06649726
ABSTRACT:
DETAILED DESCRIPTION OF THE INVENTION
1. Field of the Invention
The present invention relates to a two-component type polyurethane composition, a two-component type micro foamed polyurethane elastomer, applications thereof and a process of preparing the same. In particular, the present invention relates to a two-component type polyurethane composition and a two-component type micro foamed polyurethane elastomer both excellent in sag resistance, a process of preparing the same, a polyurethane sealant for sealing joints in buildings, doors and the like, and in bodies of cars, and a process of preparing the same.
2. Background of the Invention
Due to their excellent physical properties such as rubber elasticity, cold proof resistance and durability, polyurethane resins have been lately used as sealing materials for buildings, cars, etc. The sealing materials for use in buildings and cars are required to be applicable to the base surface of a variety of shapes. And it is particularly important for them to have such excellent sag resistance that they do not sag down while being applied to a vertical or sloping surface even to enough thickness to exhibit watertightness.
Thus, in order to prevent the fluid from sagging, mineral fillers such as surface treated calcium carbonate, colloidal silica and bentonite, which have been treated with higher fatty acid or fatty ester, or organic matter such as hydrogenated castor oil, aliphatic amide wax or polytetrafluoroethylene resin (PTFE) have been generally added to the polyurethane resins as thixotropy-imparting agent (thixotropic agent).
The use of these thixotropic agents, however, causes problems that, since a large amount of such agents must be add to the polyurethane resins so as to enhance the sag resistance, apparent viscosity of the polyurethane resins increases at the time of their application, and hence workability is deteriorated and that the resins with such agents are often poor in storage stability.
The use of amines, as thixotropic agents, has been also well known. For example, there is disclosed in Japanese Patent Publication No. 54-26274 a method of preparing a polyurethane elastomer which is characterized by reacting a polyisocyanate component and polyoxyalkylene polyamine. And there is disclosed in Japanese Patent Publication No. 53-4527 a method of preparing an adhesive based on polyurethane composed of an isocyanate-terminated prepolymer, a polyhydroxy compound and a catalyst in which part of the polyhydroxy compound is substituted with a primary amine compound having a chemical formula R(NH
2
)
n
(wherein R represents an aliphatic hydrocarbon group having 8 or less carbon atoms, n=2 to 4) in an amount of 4 to 30% by equivalent weight based on the free isocyanate group content of prepolymer.
Each of these methods, however, has a problem that it takes several seconds to several minutes from the moment of mixing a polyisocyanate component and active hydrogen component of amine, etc. to the moment of the development of thixotropy. Thus, although they are applicable in the case of hand-application with a caulking gun or mechanical-application with a low-pressure apparatus, they have no practical use in the case of application with a high-pressure apparatus which requires higher working efficiency, because it takes them too much time to allow the development of thixotropy to take place.
In such a situation, there have been demands that sealing materials should appear which enable more excellent development of thixotropy and have more excellent physical properties, thereby are applicable under various conditions such as mechanical-application, hand-application and application with a high-pressure apparatus.
In light of the above problems, the present inventors concentrated their energies on studying a two-component type polyurethane composition in which development of excellent thixotropy takes place immediately after mixing a polyisocyanate component and active hydrogen compound component. And the present inventors finally found that, for the two-component type polyurethane composition or the two-component type micro foamed polyurethane elastomer obtained from a polyisocyanate component and active hydrogen compound component, when using an alicyclic diamine as active hydrogen compound, it develops such excellent thixotropy that it is applicable under various conditions such as mechanical-application, hand-application, etc. even if it substantially contains no thixotropic agents, because the alicyclic diamine participates in the development of thixotropy, and that the above composition or elastomer has excellent sag resistance and other physical properties. The present inventors also found that the above composition or elastomer is suitable for sealing material, which led to the completion of the present invention.
OBJECT OF THE INVENTION
The present invention was made to solve the problems attendant to the prior arts as described above, and the object of the present invention is to provide a two-component type polyurethane composition and a two-component type micro foamed polyurethane elastomer which develop excellent thixotropy immediately after mixing a compound having an isocyanate group and a compound having active hydrogen, enable their application under various conditions such as mechanical-application, hand-application, etc, and in addition, have excellent sag resistance and other physical properties suitable for sealing materials, and a method of preparing the same.
SUMMARY OF THE INVENTION
The two-component type polyurethane composition according to the present invention is obtained from a principal component containing a compound having an isocyanate group and a curing agent containing a compound having active hydrogen and is characterized in that both the above principal component and the above curing agent contain substantially no thixotropic agent, the total time from the moment of mixing the above principal component and the above curing agent to the moment of the development of thixotropy is 2 seconds or shorter, the slump of the mixture of the above principal component and the above curing agent is 3 mm or smaller, the above compound having active hydrogen has flash point of 60° C. or higher, and that, when boiling the cured two-component type polyurethane composition in boiling water under atmospheric pressure for 60 minutes, change in mass of the above cured two-component type polyurethane composition before and after the boiling is 0.6% or smaller by mass.
Preferably the two-component type polyurethane composition described above has break strength of not less than 0.5 MPa and not more than 30 MPa at −30° C. and elongation at break of not less than 50% and not more than 700% at −30° C. Preferably the compound having active hydrogen described above has at least two hydroxyl groups and/or at least two amino groups.
Preferably the two-component type polyurethane composition described above has a constitutional unit having the following general formula [I]:
wherein m, n represent an integer from 1 to 5 independently, in the rate of not less than 0.001% and not more than 30% by mass.
Preferably the compound having active hydrogen described above contains alicyclic diamine.
Preferably the above alicyclic diamine is polycyclic aliphatic diamine having the following general formula [II]:
wherein m, n represent an integer from 1 to 5 independently.
Preferably the above alicyclic diamine content of the compound having active hydrogen described above is not less than 1% and not more than 50% by equivalent weight as active hydrogen group conversion on the basis of the total active hydrogen group in the same compound.
The two-component type micro foamed polyurethane elastomer according to the present invention is obtained from a principal component containing a compound having an isocyanate group, a curing agent containing a compound having active hydrogen and a foaming agent and is characterized in that both the above principal component and the above curing agent contain sub
Abe Takashi
Kawanabe Hisashi
Sakaguchi Hiroaki
Usaka Kazuto
Mitsui Chemicals Inc.
Sergent Rabon
LandOfFree
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