Water-based composition of amino-functional silicon compounds

Details Water-based composition of amino-functional silicon compounds Water-based composition of amino-functional silicon compounds

2000-02-28

2003-03-18

Shaver, Paul F. (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Silicon containing

C427S331000, C106S287110

Reexamination Certificate

active

06534667

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a composition which comprises a mixture of water-soluble, amino-functional silicon compounds which are essentially free from alkoxy groups, water, optionally a low content of alcohol and optionally a content of acid. Such compositions moreover are free from solvents, water and alcohols being excluded from the amount of solvent.
2. Description of the Related Art
Amino silanes are known as water-soluble adhesion promoters. Water-based compositions with multi-functional organopolysiloxanes are also known as adhesion promoters, cf. EP 0 716 128 A2. In these systems, the reason for the improvement in the water-solubility is essentially attributed to the amino-functional groups.
A number of further fields of application for amino-functional silanes or siloxanes are:
The use in coating systems, in the field of corrosion protection, for biocidal treatment of surfaces, in the treatment of wood, in the preparation of electro-photographic toners, as a constituent in amino-silicone fluids (U.S. Pat. No. 5,077,421), as a constituent in epoxy resins [Chemical Abstracts (1991)—CA 114: 83579s] for the preparation of organically modified glasses (EP 0 223 987 A2), as an anticancer agent [Chemical Abstracts (1983)—CA 99: 133650c], for modification of glass surfaces and glass fiber surfaces in wastewater treatment for the treatment of pigments, as a constituent in catalysts and for the preparation thereof (U.S. Pat. No. 4,053,534) and as a flocculating agent, to mention only a few examples.
It is moreover known to employ amino-functional partly hydrolyzed alkoxy silane oligomers to reduce the formation of agglomerates in inorganic powders. U.S. Pat. No. 5,543,173 thus discloses that such formulations also comprise considerable amounts of alcohol, and moreover said silane oligomers can also liberate significant amounts of hydrolysis alcohol
Since amino silanes, such as, for example, aminopropyltriethoxysilane or aminopropyltrimethoxy-silane, are water-soluble, they allow a water-based application, for example in aqueous glass fiber sizes. Also, the formation of alcohols which occurs on hydrolysis also has an adverse effect. For example, on aqueous application of aminopropyltriethoxysilane, ethanol is formed as a hydrolysis product to the extent of about 62% of the weight of silane employed. As a combustible, water-soluble liquid, ethanol reduces the flash point of such application solutions, which in general necessitates the use of expensive, explosion-proof apparatuses.
Another disadvantage of alcohol-containing solutions is the fact that for ecological and work safety reasons, the solvent alcohol must be removed by sometimes very expensive industrial procedures.
Aminoalkoxysilanes can form a maximum of one silanetriol group per molecule upon hydrolysis. Silanols and other silanol functions can crosslink with one another or with other OH functions, for example with OH functions of a substrate or of dissolved, emulsified or suspended monomeric or polymeric substances. Such OH functions could be, for example, silanol functions on silic, glass, mineral, glass fiber or mineral fiber surfaces, OH functions on cellulose, leather, paper, wood and the like, and also OH functions on metal surfaces or metal oxide surfaces and also OH functions on the surface of plastics or polymers in formulations, for example emulsions or dispersions of naturally occurring substances or plastics. To achieve a higher crosslinking density and possibly associated therewith an improvement in the use properties, two silanetriol units per molecule, for example, would be desirable. Two silanetriol units per molecule are obtained on hydrolysis of bis(trialkoxysilylalkyl)amines. However, aqueous solutions of such compounds are not stable. They tend to gel and flocculate out and therefore are not capable of application.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a water-based composition which comprises (bis)trihydroxysilylalkyl)amines or siloxanes derived therefrom, has the lowest possible content of alcohol, furthermore is free from solvents, and comprises silicon compounds which are essentially free from alkoxy groups.
The object of the invention may be accomplished with a composition, which comprises a mixture of
(a) water-soluble, amino-functional silicon compounds which are essentially free from alkoxy groups represented by the formula (I) and (II):
 NH
2
[(CH
2
)
2
NH]
x
(CH
2
)
3
SiO
1.5
  (I)
(SiO
1.5
)(CH
2
)
3
[NH(CH
2
)
2
]
y
NH[(CH
2
)
2
NH]
x
(CH
2
)
3
SiO
1.5
  (II)
 wherein
x is 0, 1 or 2, and
y and z are each independently 0, 1 or 2, and
(b) water,
It has been found, surprisingly, that a low-viscosity, generally, largely storage-stable composition which comprises a mixture of water-soluble, amino-functional silicon compounds which are essentially free from alkoxy groups, water, optionally a low content of alcohol and optionally a content of acid is obtainable by mixing at least one amino silane of the general formula III:
NH
2
[(CH
2
)
2
NH]
x
(CH
2
)
3
Si(OR)
3
  (III)
where
x is 0, 1 or 2, and R is a linear or branched alkyl group having 1 to 4 C atoms,
and/or condensation products thereof, and
at least one amino silane of the general formula IV:
(RO)
3
Si(CH
2
)
3
[NH(CH
2
)
2
]
y
NH[(CH
2
)
2
NH]
z
(CH
2
)
3
Si(OR)
3
  (IV)
 where y and z are 0, 1 or 2 and are identical or different, and R is a linear or branched alkyl group having 1 to 4 C atoms,
and/or condensation products thereof,
adding water and optionally acid, carrying out hydrolysis and removing essentially all of the hydrolysis alcohol produced. Condensation products of amino silanes of the general formula III or IV are understood as meaning those dimeric, trimeric, tetrameric or higher oligomeric products which as a rule are obtainable by condensation and/or pre-hydrolysis of the particular monomers, alcohol being split off.
The inventive composition moreover is usually obtained in a liquid form which is easy to apply, and is generally essentially free from solvent. When the composition according to the invention is used, because of the silicon compounds of the general formulae I and II contained therein, a higher crosslinking density in the polymeric cured siloxane structure and a significant improvement in the mechanical, chemical and thermal properties of treated substances, for example composite materials, such as, for example, glass fiber- and mineral fiber-reinforced plastics, paints and coatings and polymers with a filler content, can be achieved.
The composition according to the invention can also suitably be diluted with water in any ratio, no additional hydrolysis alcohol being formed. Generally, the present composition is stable to storage in an outstanding manner for more than 12 months.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description.
DETAILED DESCRIPTION OF THE INVENTION
The composition of the invention may contain alcohol, acid, or both alcohol and acid. The composition according to the invention preferably has a content of alcohol of less than 5% by weight, particularly preferably less than 1% by weight, especially preferably from 1 ppm by weight to 0.5% by weight. In particular, such a composition can comprise methanol and/or ethanol as the alcohol.
The composition according to the invention furthermore has a content of silicon compounds of less than 60% by weight, preferably less than 50% by weight, and the content of silicon compounds is particularly preferably 0.1 to 40% by weight, and especially preferably 0.5 to 40% by weight.
The weight ratio here of the silicon compounds of the general formula I and of the general formula II in a composition according to the invention is suitably I/II≧1, the general formulae I and II

Affiliated with

Also associated with

Rating

Water-based composition of amino-functional silicon compounds does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Water-based composition of amino-functional silicon compounds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Water-based composition of amino-functional silicon compounds will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3010967