Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
2000-06-21
2003-02-04
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...
C556S425000, C008SDIG001, C008S115600
Reexamination Certificate
active
06515095
ABSTRACT:
This invention relates to nitrogen atom-containing polysiloxanes which can be synthesized from inexpensive reactants and useful as the main component of fiber and fabric finishing agent compositions for imparting softness and durability of home laundering to a variety of fibers or fibrous materials, methods for preparing the same, and fiber and fabric finishing agent compositions.
BACKGROUND OF THE INVENTION
A number of organopolysiloxanes such as dimethylpolysiloxanes, epoxy group-containing polysiloxanes, and nitrogen atom-containing polysiloxanes have been widely used as treating agents for imparting softness and smoothness to a variety of fibers or fibrous materials. Most widely used among others are the nitrogen atom-containing polysiloxanes, especially aminoalkyl group-containing organopolysiloxanes, which can impart satisfactory softness to a variety of fibers or fibrous materials. More specifically, fiber treating agents based on organopolysiloxanes having such aminoalkyl groups as —C
3
H
6
NH
2
and —C
3
H
6
NHC
2
H
4
NH
2
are widely used because of their softness capability as disclosed in JP-B 48-1480, JP-B 54-43614, JP-B 57-43673, JP-A 60-185879, JP-A 60-185880, and JP-A 64-61576.
These nitrogen atom-containing polysiloxanes are generally synthesized by equilibrating with alkalis dimethyl cyclics such as 1,1,3,3,5,5,7,7-octamethyl-cyclotetrasiloxane, nitrogen atom-containing trialkoxy-silanes, nitrogen atom-containing cyclopolysiloxanes, etc.
In the silicone industry, the dimethylsiloxy sources for polysiloxanes are dimethyl cyclics obtained by hydrolyzing dimethyldichlorosilane and distilling the hydrolyzate, and &agr;,&ohgr;-dihydroxydimethylpolysiloxane which is the still residue. Since the former is in greater demand than the latter, the latter is converted by cracking into the former as needed. As compared with the former, the latter is inexpensive.
Since the nitrogen atom-containing polysiloxanes as typified by aminoalkyl group-containing organopolysiloxanes are currently used for general purposes, there is an increasing demand for cost reduction. If &agr;,&ohgr;-dihydroxydimethylpolysiloxane could be used as the starting reactant, it would become possible to synthesize nitrogen atom-containing polysiloxanes in an inexpensive manner. There is a need for such a synthetic method.
As the method for obtaining higher molecular weight polysiloxanes from &agr;,&ohgr;-dihydroxydimethylpolysiloxane as the starting reactant, alcohol-removing reaction with alkoxysilanes is known. However, a high temperature or a catalyst is essential for this reaction because of low reactivity. British Patent No. 9,188,239 discloses the use of an amino compound salt with phosphoric acid or carboxylic acid as the catalyst. Japanese Patent No. 2,857,203 discloses the use of strontium hydroxide or barium hydroxide as the catalyst. However, the amino compound salts with phosphoric acid or carboxylic acid give rise to a yellowing problem when applied to white or tint color fibers or fibrous materials. Additionally, it is difficult to remove the catalyst from the product since most of these catalysts are liquid. On the other hand, such catalysts as strontium hydroxide and barium hydroxide also become foreign matters in the fiber treating step and cause cracking of polysiloxanes. This necessitates an extra step of removing the catalyst. An efficient reaction method without a need for a catalyst is thus demanded.
Among prior art nitrogen atom-containing poly-siloxanes, aminoalkyl group-containing organopolysiloxanes are most common. They suffer from the problem that the softness imparted thereby lowers during long-term use or by repeated washing. There is a need for nitrogen atom-containing polysiloxanes having long-lasting performance.
JP-B 46-3627 discloses the condensates of &agr;,&ohgr;-dihydroxydimethylpolysiloxane with amino group-containing alkoxysilanes, but reaction conditions are described nowhere. In Examples described therein, the ratio of the moles of &agr;,&ohgr;-dihydroxydimethylpolysiloxane to the moles of amino group-containing alkoxysilane is 0.07 or 0.02. These ratios are outside the range used in the present invention. Also, JP-A 6-184257 discloses analogous condensates, but no reference is made to the preparation method. No alkoxy groups are left in these condensates, that is, all alkoxy groups are replaced by &agr;,&ohgr;-dihydroxydimethylpolysiloxane. This structure differs from the polysiloxanes of the present invention. Further, U.S. Pat. No. 3,355,424 discloses piperidyl group-containing organopolysiloxanes which are prepared by hydrolytic condensation of an addition product of allyloxypiperidine and a dialkoxysilane. This preparation method differs from the method of the present invention. No alkoxy groups are left in these condensates.
Further, fibers treated with organopolysiloxanes having such aminoalkyl groups as —C
3
H
6
NH
2
and —C
3
H
6
NHC
2
H
4
NH
2
suffer from degradation of amino groups by heat or ultraviolet radiation during heat treatment, drying or aging. In particular, white or tint color fibers or fibrous materials treated with such organopolysiloxanes have the serious problem that their color changes to yellow and their softness lowers during heat treatment, drying or aging.
For preventing the yellowing problem, it was proposed to modify aminoalkyl group-containing organopolysiloxanes, for example, by reacting the aminoalkyl groups with organic acid anhydrides or chlorides (JP-A 57-101046), epoxy compounds (JP-A 59-179884), higher fatty acids (JP-A 1-306683), and carbonates (JP-A 2-47371).
As compared with the unmodified aminoalkyl group-containing organopolysiloxanes, these modified organopoly-siloxanes were found to be improved in anti-yellowing effect, but to a still insufficient extent. With respect to the impartment of softness and smoothness to fibers or fabrics, the modified ones are rather inferior to the unmodified ones.
SUMMARY OF THE INVENTION
An object of the invention is to provide a novel and improved nitrogen atom-containing polysiloxane which is effective as a main component of a fiber-treating agent composition for imparting softness and smoothness to fibers or fibrous materials while minimizing the yellowing thereof.
Another object of the invention is to provide a novel and improved nitrogen atom-containing polysiloxane which is effective as a main component of a fiber and fabric finishing agent composition for imparting to fibers or fibrous materials a softness which is not only high at the initial, but also lasts even after washing.
A further object of the invention is to provide a method for preparing the nitrogen atom-containing polysiloxane.
A still further object of the invention is to provide a fiber and fabric finishing agent composition comprising the nitrogen atom-containing polysiloxane as a main component.
We have found that an organopolysiloxane having some alkoxy groups left intact is effective for enhancing the bond to a substrate and improving softness, and durability of home laundering. In the resulting polymer, amino group-containing silicon atoms are not present as blocks, but regularly distributed in accordance with the degree of polymerization of &agr;,&ohgr;-dihydroxypolysiloxane. This feature is the largest difference from the polymers prepared by the prior art technique of alkali equilibration. The regular distribution of amino groups in the polymer is effective for improving softness and durability. The invention is predicated on this finding.
In a first aspect, the invention provides a nitrogen atom-containing polysiloxane having at least one polymer terminus represented by the general formula (1).
Herein R
1
is a nitrogen-free, substituted or unsubstituted, monovalent organic group of 1 to 20 carbon atoms, R
2
is a monovalent organic group containing at least one nitrogen atom, R
3
is an organoxy group represented by —OR
1
, and p is a positive number of 2 to 2,000.
In a second aspect, the invention provides a method for preparing a nitrogen atom-containing polysiloxane as defined above, comprising
Isobe Kenichi
Omura Naoki
Millen White Zelano & Branigan P.C.
Moore Margaret G.
Shin-Etsu Chemical Co. , Ltd.
LandOfFree
Nitrogen atom-containing polysiloxanes, their preparation,... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Nitrogen atom-containing polysiloxanes, their preparation,..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nitrogen atom-containing polysiloxanes, their preparation,... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3168242