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
2001-06-11
2004-09-14
Yoon, Tae H. (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...
C524S588000, C524S591000, C524S837000, C524S858000, C427S207100, C428S448000
Reexamination Certificate
active
06790903
ABSTRACT:
The invention relates to a polymer dispersion comprising water and at least 60% by weight of an organic polymer containing at least one group of the general formula (I)
—A—Si (Z)
n
(OH)
3-n
(I)
in which A is CH
2
or a linear or branched, saturated or unsaturated alkylene radical having from 2 to about 12 C atoms or is an arylene radical having from about 6 to about 18 C atoms or an arylenealkylene radical having from about 7 to about 19 C atoms, Z is CH
3
, O—CH
3
or a a linear or branched, saturated or unsaturated alkyl radical or alkoxy radical having from 2 to about 12 C atoms and n is 0, 1 or 2, or a condensation product of at least two such groups.
The invention likewise relates to a composition comprising an organic polymer containing at least one group of the general formula I and at least one further organic polymer or a mixture of two or more further organic polymers.
Silane-terminated, moisture-curing one-component polyurethane compositions are increasingly being used as flexible coating, sealing and adhesive compositions in construction and in the automobile industry. In such applications, stringent requirements are imposed on the extensibility, adhesion and curing rate. Moreover, such silane-terminated polymers often have water repellency properties, which give the sealing, coating or adhesive compositions prepared from them excellent water resistance and heat resistance.
The prior art discloses alkoxysilane-terminated polymers which are used as flexible sealing, coating and adhesive compositions.
For instance, EP-B 0 549 626 describes alkoxysilane-terminated, moisture-curing, one-component polyurethanes which find application, for example, as joint-sealing compositions. The compounds disclosed rapidly form a skin and rapidly attain freedom from tack, even after prolonged storage. A disadvantage of the compounds described, however, is that owing to their reactive end groups they have to be stored under moisture exclusion conditions and over a prolonged period of storage there is the risk of irreversible changes in properties.
In order to remedy this disadvantage, attempts have been made in the past to prepare dispersions of silane-terminated polymers. For example, DE-A 36 37 836 describes an aqueous silicone dispersion obtainable from an OH-terminated polydiorganosiloxane, (organo) metallic compounds and a siliconate. The products described have a curing time of at least one day. Polymers containing at least one group of the general formula —A—Si(Z)
n
(OH)
3-n
are not disclosed in the document.
DE-C 42 15 648 relates to a dispersion of alkoxysilane-terminated polymers whose chain contains amino groups capable of forming salts. Dispersions having a solids content of not more than 41% by weight are described. When such dispersions are used to bond absorbent materials, the high water content imposes a high water load on the substrate. In the case of paper bonds, for example, this may lead to dimensional changes in the substrate, which are unwanted.
WO 91/08244 relates to masonry preservatives which comprise polyurethanes terminated by alkoxysilane groups. The polymer contents of the dispersions described, however, are very low, at between 5 and 30% by weight. Moreover, the dispersions have a pH of ≧10. Therefore, the dispersions described are useful neither as surface coating compositions for producing coatings with mechanical load-bearing properties, nor as sealants or adhesives.
DE-US 25 58 653 relates to silanol-containing urethane dispersions. The polyurethanes described contain hydrolyzable or hydrolyzed silyl end groups and in the polymer backbone possess solubilizing or emulsifying groups, especially carboxyl groups. The dispersions described have polymer contents of up to about 40% by weight. The polymers described are required to contain, as well as the solubilizing groups, urea groups, which are produced by chain extension of a prepolymer with isocyanate end groups in water. At high siloxane contents, the compounds described exhibit a high level of formation of coagulum, and their water resistance is unsatisfactory.
A problematic consequence with all of the prior art dispersions of silanol-terminated polyurethanes is that the achievable solids contents are low. Such low solids contents are, however, beset by a number of drawbacks, whose elimination was an object of the present invention. This object is achieved by means of a polymer dispersion comprising water and at least 60% by weight of an organic polymer containing at least one group of the general formula —A—Si(Z)
n
(OH)
3-n
(formula I).
The invention accordingly provides a polymer dispersion comprising water and at least 60% by weight of an organic polymer containing at least one group of the general formula I
—A—Si (Z)
n
(OH)
3-n
(I)
in which A is CH
2
or is a linear or branched, saturated or unsaturated alkylene radical having from 2 to about 12 C atoms or is an arylene radical having from about 6 to about 18 C atoms or an arylenealkylene radical having from about 7 to about 19 C atoms or an alkyl-, cycloalkyl- or aryl-substituted siloxane radical having from about 1 to about 20 Si atoms, Z is CH
3
, O—CH
3
or is a linear or branched, saturated or unsaturated alkyl radical or alkoxy radical having from 2 to about 12 C atoms, and n is 0, 1 or 2, or a condensation product of at least two such groups.
Suitable organic polymers containing at least one group of the general formula I are all organic polymers that are dispersible in water by by means of suitable methods. In one preferred embodiment of the invention, the composition of the invention comprises as organic polymer a polymer selected from the group consisting of polyurethanes, polyesters, polyamides, polyethers, polyacrylates, polymethacrylates, polystyrene, polybutadiene, polyethylene, polyvinyl esters, ethylene/&agr;-olefin copolymers, styrene/butadiene copolymers, styrene/acrylonitrile copolymers, ethylene/vinyl acetate copolymers, or a mixture of two or more of said polymers.
Said polymers may, where possible, be provided with solubilizing groups, i.e, groups capable of dissociation in water. In one preferred form of the invention, however, the organic polymers either have no water-dissociable groups or, where such groups are present, the conditions in the polymer dispersion of the invention are chosen such that the water-dissociable groups are present in dissociated form only to a minor extent if at all.
For the purposes of the present text, a “water-dissociable group” means a functional group which, in an acidic, neutral or basic aqueous solution, undergoes dissociation into an anion and a cation.
In one preferred embodiment of the invention, a polyurethane is used as organic polymer. Suitable polyurethanes are preparable, for example, using the following building blocks:
a) at least one polyisocyanate,
b) at least one polyol,
c) at least one alkoxysilane of the general formula II
X—A—Si (Z)
n
(OR)
3-n
(II)
in which X is a radical containing at least one isocyanate-reactive functional group, for example at least one OH, SH, NH or COOH group, or at least one OH-reactive group, for example, at least one carboxyl; anhydride, NCO or oxirane group, or a mixture of two or more such groups, A is CH
2
or is a linear or branched, saturated or unsaturated alkylene radical having from 2 to about 12 C atoms or is an arylene radical having from about 6 to about 18 C atoms or an arylenealkylene radical having from about 7 to about 19 C atoms or an alkyl-, cycloalkyl- or aryl-substituted siloxane radical having from about 1 to about 20 Si atoms, Z is CH
3
, O—CH
3
or is a linear or branched, saturated or unsaturated alkyl radical or alkoxy radical having from 2 to about 12 C atoms, R is CH
3
or a linear or branched, saturated or unsaturated alkyl radical having from 2 to about 12 C atoms, and n is 0, 1 or 2.
If desired, it is possible in addition to use up to about 20% by weight of chain extender (building block d), based on the polyurethane weight.
Suitable isocyanates (building block a) are any desired o
Ernst Wolfgang
Klauck Wolfgang
Klein Johann
Loth Helmut
Majolo Martin
Henkel Kommanditgesellschaft auf Aktien (Henkel KGaA)
Woodcock & Washburn LLP
Yoon Tae H.
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