Organosiloxane compound with one end stopped with an aminoalkyl group and a manufacturing method thereof

A novel organosiloxane compound of the formula ##STR1## wherein R is either hydrogen atom or an alkyl having 1-3 carbon atoms, and n is an integer such that 0.ltoreq.n.ltoreq.1,000, is effective in improving surface characteristics of synthetic silicon resins in which it is contained such as oxygen permeability and surface slip factor, and is produced by reacting a cyclic silazane of the formula ##STR2## with a silanol of the formula ##STR3##

BACKGROUND OF THE INVENTION 
The present invention relates to a novel organosiloxane compound one of 
whose ends is stopped with an aminoalkyl group and a method of 
manufacturing such a compound. 
An organosiloxane compound with both ends stopped with aminoalkyl is known. 
There are various examples of such a compound, and one of them is 
represented by the following formula wherein both ends are stopped with an 
aminopropyl group: 
##STR4## 
These organosiloxanes with both ends stopped with aminoalkyl are used to 
obtain modified siloxane compounds. The modification of the 
organosiloxanes lies in reactions between the amino groups of the 
organosiloxanes and the "acid anhydride group" [--CO--O--CO-- in 
(RCO).sub.2 0], carboxyl group, isocyanato group, epoxy group, etc. of 
other monomer compounds. The thus modified siloxane compounds are 
effective, when included in the raw materials for syntheses of a polyimide 
resin, a polyamide resin, or a polyurea resin, in imparting to these 
resins high oxygen permeability, high surface slip factor, and other 
desirous surface characteristics which are inherent in silicone resins. 
However, the surface improving effects caused by the inclusion of a 
siloxane both of whose ends are stopped with aminoalkyl are not 
satisfactory. Further improvements, especially in oxygen permeability and 
surface slip factor in the resulting synthetic resins are desired. It is 
believed that the existence of the relatively reactive amino group at each 
end of the siloxane chain leads to a reaction that causes the siloxane 
chain to have no free end, whereby the surface improving effects of the 
siloxane are spoiled. 
Furthermore, when reacted with a polyfunctional monomer which has in it 
three or more functional groups such as an acid anhydride group, carboxyl 
group, isocyanato group, and epoxy group, an organic siloxane with both 
ends stopped with aminoalkyl undergoes gelatinization to thereby lose its 
surface improving effects. 
It was speculated that the use of an organosiloxane with only one end 
stopped with an aminoalkyl group would solve these problems. However, 
neither such organosiloxane nor a method of manufacturing the same was 
known. 
OBJECT OF THE INVENTION 
It is, therefore, the primary object of the invention to provide an 
organosiloxane compound only one of whose ends is stopped with an 
aminoalkyl group and a method of manufacturing such a compound. 
It is another object of the invention to provide an organosiloxane compound 
which is effective to improve surface characteristics of synthetic resins 
produced therefrom such as oxygen permeability and surface slip factor, 
and a method of manufacturing such a compound. 
The foregoing and other objects, features and advantages of the present 
invention will be apparent from the following detailed description 
thereof. 
SUMMARY OF THE INVENTION 
The foregoing objects are attained by an organosiloxane compound one of 
whose ends is stopped with an aminoalkyl group generally represented by 
Formula (I): 
##STR5## 
wherein R is either hydrogen atom or an alkyl having 1-3 carbon atoms, and 
n is an integer such that 0.ltoreq.n.ltoreq.1,000. 
In practice, however, the organosiloxane compound of Formula (I) is always 
prepared in the form of a mixture of numerous molecules of Formula (I) 
differing in the number n depending on the degree of polymerization, and 
therefore the actual requirement is that the mean value of n is 0, 1,000 
or any whole or fractional number therebetween. 
The organosiloxane compound (I) is obtained, for example, by reacting a 
cyclic silazane represented by Formula (II) wherein R is the same as that 
in (I): 
##STR6## 
with a silanol or a mixture of silanols represented by Formula (III): 
##STR7## 
wherein the integer n is equal to that in (I).

DETAILED DISCLOSURE 
Of the compounds of Formula I, those wherein R is methyl, and those wherein 
n is an integer from 0 to 500 are preferred. 
The cyclic silazane (II) is obtained, for example, by means of the method 
described in U.S. Pat. No. 3,146,250, whose disclosure is incorporated 
herein by reference, that is, by reacting a compound of the formula 
EQU Cl(CH.sub.3).sub.2 Si(CH.sub.2).sub.3 Cl 
with ammonia or an alkyl amine, preferably of 1 to 3 carbon atoms, i.e., 
methyl amine, ethyl amine and propyl amine. 
The reaction between the cyclic silazane (II) and the silanol (III) is 
normally conducted in the absence of a solvent, or, depending on the 
requirements, in an aprotic organic solvent, such as (i) an aromatic 
hydrocarbons solvent, e.g. benzene, toluene, xylene, (ii) an aliphatic 
hydrocarbons solvent, e.g. octane, (iii) a chlorinated hydrocarbons 
solvent, e.g. carbon tetrachloride, trichloroethane, (iv) a ketone, e.g. 
methyl ethyl ketone, methyl isobutyl ketone, (v) an ether, e.g. 
tetrahydrofuran, butyl ether, and (vi) an ester, e.g. ethyl acetate, butyl 
acetate. Although the reaction can be conducted at a temperature between 
0.degree. and 200.degree. C., it preferably is conducted at a temperature 
between 0.degree. and 120.degree. C. 
The relative proportions of the cyclic silazane (II) and the silanol (III) 
in the reaction mixture are determined based on the desired organosiloxane 
compound with one end stopped with an aminoalkyl group (I). Preferably, 
the amount of the cyclic silazane (II) employed is 5 to 20 mol. % greater 
than its stoichiometrically equivalent value with respect to the silanol 
(III), and when the reaction is completed, the unreacted cyclic silazane 
is removed by distillation. 
EXAMPLES 
In the following description of the examples, the method of the present 
invention is more clearly explained. 
EXAMPLE 1 
Synthesis of N-methyl-.gamma.-aminopropylpentamethyldisiloxane: 
9.0 g. (0.1 mol) of trimethylsilanol and 12.9 g. (0.1 mol) of the cyclic 
silazane compound represented by Formula (IV) were mixed together in a 
flask at room temperature. An exothermic reaction immediately occurred. 
##STR8## 
After the reaction continued for thirty minutes, the reaction mixture was 
distilled at 200.degree. to 202.degree. C. A colorless transparent liquid 
weighing 17 g. was obtained as the distillate. The yield of the liquid was 
78%. The H-NMR spectrum, IR spectrum, and mass spectrum of the liquid were 
observed. The results were: 
.sup.1 H-NMR (.delta., CCl.sub.4, ppm): 2.50 (N--CH.sub.2 --C, t, 2H), 2.35 
(N--CH.sub.3, s, 3H), 1.77-1.17 (C--CH.sub.2 --C and N--H, m, 3H), 
0.77-0.32 (C--CH.sub.2 --Si, m, 2H), 0.08 (SiCH.sub.3, s, 15H). 
IR(KBr, cm.sup.-1): 3290 (N--H), 1254 (Si--CH.sub.3), 1061 (Si--O) mass 
m/e: 219 (M.sup.+) 
According to these data, the transparent, liquid was a siloxane compound 
represented by Formula (V): 
##STR9## 
EXAMPLE 2 
Synthesis of dimethylsiloxane having one end stopped with 
N-methyl-.gamma.-aminopropyl: 
(1) A dimethylsiloxane oligomer of a mean molecular weight of 2220 
represented by Formula (VI) was obtained by the reaction of 9 g. (0.1 mol) 
of trimethylsilanol with 207.2 g. of hexamethylcyclotrisiloxane, in the 
presence of 25 mg. of a catalyst having Formula (VII) and 8 g. of 
acetonitrile: 
##STR10## 
(2) The dimethylsiloxane oligomer obtained in step (1) in an amount of 
216.2 g. was heated to and kept at a temperature of 80.degree. C., while 
15.5 g. (0.12 mol) of the same cyclic silazane used in Example 1 was 
dripped into the dimethylsiloxane oligomer. From the start of the dripping 
the reaction was continued for two hours. Then, the volatile components 
were removed by distillation under a reduced pressure of 3 mm Hg and at a 
temperature of 130.degree. C., leaving 208 g. of colorless transparent 
liquid as the residual liquid. The results of the IR spectrum, a 
quantitative analysis of amino group, and the gel permeation 
chromatographic analysis were as follows: 
IR(KBr, cm.sup.-1): 3400 (N--H), 1261 (Si--CH.sub.3), 1094, 1024 (Si--O) 
amine equivalence (molecular weight per one amino group): 2136 
(theoretically 2291) 
GPC: 
The number average molecular weight (Mn) was 2900 on the supposition that 
the liquid substance were a polystyrene. 
The weight average molecular weight (Mw) was 3600 on the supposition that 
the liquid substance were a polystyrene. 
The degree of polydispersion (Mw/Mn) was 1.24. 
It follows from these data that the formula of the liquid substance is as 
follows: 
##STR11## 
wherein n is about 28. 
The siloxane compound of Example 1 represented by Formula (V), and the 
siloxane compound of Example 2 represented by Formula (VIII) are novel in 
that each has only one end stopped with an aminoalkyl group. This kind of 
siloxane compound is effective in improving the surface qualities of 
various resins when it is added therein during the manufacturing process. 
Since the siloxanes obtained in Examples 1 and 2 have N-methylaminopropyl 
at only one end, the other end of each remains free even if these 
siloxanes are reacted with monomer compounds carrying other kinds of 
functional groups such as carboxyl, isocyanate and epoxy, in a synthesis 
of a resin; wherefore the resulting modified silicone resin has far 
improved surface characteristics such as slip factor compared with a 
conventional silicone resin based on a corresponding siloxane having an 
amino group at both its ends. 
Also, because the siloxane compound of the invention cannot participate in 
the polymerization, and, being monofunctional, does not gelatinize even 
when attacked by a trifunctional monomer or more functional ones, one can 
obtain desirably modified siloxane resins. 
Furthermore, since the structure of siloxane compounds of this invention is 
such that they exhibit polarity, they can be employed as surface active 
agents as well as emulsifying agents and auxiliary emulsifying agents. The 
surface activation effect is improved when the siloxane compound is in 
acid addition salt form, viz., a salt of an organic or inorganic acid, 
e.g., an acetate, a hydrochloride, or an ammonium salt which are obtained 
by reacting the amino group in the aminoalkyl with acetic acid, 
hydrochloric acid, or an alkyl halide, respectively. 
Contemplated equivalents of the compounds of this invention are those 
otherwise corresponding thereto wherein one, and/or one or both of methyl 
groups on the bridging silicon atom or atoms is another non-interfering 
aliphatic or aryl group, e.g., ethyl or phenyl. 
While this invention has been described in terms of specific embodiments 
thereof, other forms may be readily adapted by one skilled in the art. 
Accordingly, the scope of the invention is to be limited only by the 
claims following.