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
1999-11-08
2001-06-26
Cain, Edward J. (Department: 1714)
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...
C556S458000
Reexamination Certificate
active
06251981
ABSTRACT:
TECHNICAL FIELD
The present invention relates to the novel polyalkoxysiloxane compounds which, when blended in the existing coatings, coating solutions or resin compositions containing fillers such as various types of powders, do not affect their storage stability and compatibility of the components and are capable of, or useful for, providing such functions as stain resistance, weather resistance, scratch resistance, acid resistance, heat resistance, water resistance and solvent resistance to the coats or coating films.
The present invention also relates to the novel aqueous emulsion-forming compositions containing the said polyalkoxysiloxane compound of the present invention, which, when blended in the existing water-based coatings or aqueous coating solutions, can maintain storage stability and compatibility and are capable of providing such functions as stain resistance and weather resistance to the obtained coats or coating films.
BACKGROUND ART
Recently, low-molecular weight polyalkoxysiloxane compounds having alkoxyl groups, such as those obtained from partial hydrolysis/condensation of tetramethoxysilane, tetraethoxysilane, tetrabutyoxysilane or the like, are used with increasing popularity in the industries. For instance, “MKC Silicate MS51” and “MKC Silicate MS56” are produced and sold by Mitsubishi Chemical Corporation as partial hydrolysis/condensation products of tetramethoxysilane. These partial hydrolysis/condensation products of tetramethoxysilane are added to the existing coatings, coating solutions to be applied for surface treatment of powders and various other types of bases, and resin compositions containing fillers such as inorganic powders, for the purpose of providing the useful functions such as stain resistance, weather resistance, scratch resistance, acid resistance and heat resistance to the coats or coating films.
However, addition of such partial hydrolysis/condensation products of tetramethoxysilane to the coatings, coating solutions or resin compositions may affect their storage stability. Specifically, such addition is causative of such problems as increase of viscosity and inducement of caking of the coatings or coating compositions during storage or in the course of preparation thereof.
“Ethyl Silicate ES40” Colcoat Co., Ltd. etc., as partial hydrolysis/condensation products of tetraethoxysilane, and “MKC Silicate BTS” (Mitsubishi Chemical Corporation), etc., as partial hydrolysis/condensation products of tetrabutoxysilane are commercially produced and sold. These alkoxysilanes and their partial hydrolysis/condensation products have little probability of causing rise of viscosity or caking when added to the said coatings. In some cases, however, they fail to show their effect of providing the envisioned functions, such as stain resistance, scratch resistance, heat resistance, etc., to the finally obtained coats. Especially, the coats would prove unsatisfactory in hardness.
It has been desired to offer the partial hydrolysis/condensation products of alkoxysilane compounds which, when blended in coatings, can maintain or improve their storage stability and compatibility and also contribute to providing such functions as stain resistance, weather resistance, scratch resistance, acid resistance and heat resistance to the finally obtained coats or coating films.
Especially when these alkoxysilanes or their partial hydrolysis/condensation products are blended in the water-based coatings, there would arise such problems as reduced compatibility of the components, increase of viscosity, gelation, and even cissing in the coats or coating films, resulting in marred appearance of the coats, and these problems have been a bar to utilization of the said products for water-based coatings. In recent years, solvent-based coatings has been changed to water-based ones for the benefit of environmental protection and safety, and accordingly it has been required to provide the partial hydrolysis/condensation products of alkoxysilane compounds which, when blended in water-based coatings, won't impair their storage stability and show an outstanding effect in providing such functions as stain resistance, weather resistance, scratch resistance, acid resistance, water resistance and solvent resistance to the coats.
DISCLOSURE OF THE INVENTION
As a result of the present inventors' earnest studies to solve the above subject matter, it has been found that the polyalkoxysiloxane compounds represented by a specific rational formula have an excellent effect in developing the functions such as stain resistance of the coats, and also contribute to maintaining storage stability in the liquid state when blended with various types of component materials. It has been further found that these polyalkoxysiloxane compounds are capable of maintaining a stable liquid state even when far increased in molecular weight in comparison with the partial hydrolysis/condensation products of various types of tetraalkoxysilanes which have been available as polyalkoxypolysiloxanes.
The present invention has been attained on the basis of the above finding, and its aspects are shown as follows.
In the first aspect of the present invention, there are provided polyalkoxysiloxane compounds represented by the rational formula: SiO
x
(OR
1
)
y
(OR
2
)
z
, wherein z/(y+z)=0.05 to 0.5 by mole, 0.5≦x≦1.5, 2x+y+z=4, R
1
is a methyl group, an ethyl group or mixture thereof, and R
2
is an organic group different from R
1
.
In the second aspect of the present invention, there are provided polyalkoxysiloxane compounds represented by the rational formula: SiO
x
(OR
1
)
y
(OR
2
)
z
, wherein 0.5≦x≦1.5, 2x+y+z=4, R
1
is a methyl group and/or an ethyl group, and R
2
is at least one of the alkyl groups having 3 to 4 carbon atoms.
In the third aspect of the present invention, there are provided the polyalkoxysiloxane compounds whose haze factor A is not more than 2.0.
In the fourth aspect of the present invention, there is provided an aqueous emulsion-forming composition comprising
component (A) of a polyalkoxysiloxane compound represented by the rational formula SiO
a
(OR
1
)
b
(OR
2
)
c
, and
component (B) of a nonionic surfactant,
wherein 0.5≦a≦¼, c/(b+c)=0.05 to 0.5, 2a+b+c=4, R
1
is a methyl group or an ethyl group, and R
2
is an organic group different from R
1
.
In the fifth aspect of the present invention, there is provided an aqueous emulsion-forming composition comprising:
component (A) of a polyalkoxysiloxane compound represented by the rational formula SiO
a
(OR
1
)
b
(OR
2
)
c
component (B) of an organic solvent having a solubility parameter (SP) of not more than 9.5, and
component (C) of a nonionic surfactant,
wherein 0.5≦a≦1.4, c/(b+c)=0.05 to 0.5, 2a+b+c=4, R
1
is a methyl group or an ethyl group, and R
2
is an organic group different from R
1
.
The present invention is described in detail below.
First, the first to third aspects of the present invention pertaining to the polyalkoxysiloxane compounds are explained.
The polyalkoxysiloxane compounds of the present invention are represented by the rational formula SiO
x
(OR
1
)
y
(OR
2
)
z
. The “polyalkoxysiloxane compounds” referred to in the present invention are compounds having as their backbone a siloxane skeleton represented by the formula (Si—O)
n
, with an alkoxyl group attached to the Si atom. The said siloxane skeleton may be linear, cyclic or branched.
The polyalkoxysiloxane compounds of the present invention are usually provided as a composition having a molecular weight distribution, but it is essential that the composition of these compounds be represented by the above-shown rational formula.
When x<0.5 in the above formula, the compounds may be unsatisfactory in their effect of providing the specific functions to the coats when the compounds are blended in an existing coating, coating solution or filled resin composition and used for coating. Also, such compounds are low in the degre
Katsumata Haruo
Kobayashi Hiroshi
Matsuzoe Nobuyuki
Ooba Kenji
Sawai Takeshi
Cain Edward J.
Conlin David G.
Dike Bronstein Roberts & Cushman IP Group
Edwards & Angell LLP
Mitsubishi Chemical Company
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