Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
1999-12-07
2002-06-11
Michl, Paul R. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
Reexamination Certificate
active
06403751
ABSTRACT:
TECHNICAL FIELD
The invention relates to copolymers of hydrogen siloxanes and unsaturated compounds. More specifically, the present invention relates to copolymers of hydrogen siloxanes and unsaturated compounds, wherein at least some of the SiH groups have been converted into silanol groups or reactive derivatives thereof and/or at least some of the SiH groups have silanol groups or reactive derivatives thereof bonded to them. The instant invention also relates to adhesive solutions made from said copolymers, to the use of said copolymers to promote adhesion between condensation-crosslinking silicone relining compositions and protheses. Finally, the instant invention relates to the use of said copolymers to promote the adhesion of condensation-crosslinking silicone impression compositions to impression trays, and to other uses.
BACKGROUND ART
Materials for dental prostheses generally consist of polymethylmethacrylate or of copolymers of different methacrylates. When a prosthesis no longer fits well, it must be manufactured afresh or relined (corrected). This relining may be effected with prosthesis material again (a hard relining) but it may also be necessary to choose a significantly softer material for such purposes (a non-hardening relining). With the average age increasing, there is a considerable rise in the demand for the last-mentioned soft materials.
Customary soft relining materials consist of polymethacrylates to which plasticiser has been added or of silicone. The polymethacrylates to which plasticiser has been added can be polymerised onto the (polymethylmethacrylate) prosthesis material, but in the course of a few months become harder to the point of brittleness as a result of the plasticiser's dissolving out. Relinings with silicone elastomers do not exhibit such brittleness. They lemain soft over a prolonged period, but on the other hand the provision of a firm bond between silicone elastomers and polymethacrylates always presents a considerable problem. Even when attempts are made to join the layers mechanically by etching or mechanical roughening, the silicone layer becomes detached from the prosthesis after a few weeks or even after a few days.
Several methods of solving this problem by chemical means have been described. For example, DE 196 35 696 A1 describes polymers containing reactive groups, such as —OH or —NH, to which hydrogen silicone units are linked, with hydrogen being removed. Solutions of such SiH-group-containing copolymers, after being applied to the surface of a prosthesis, are able to react with and become bonded to an addition-crosslinking vinyl silicone layer applied thereto. Since the hydrogen siloxane units are linked via —C—O—Si— bonds or via —C—NH—Si— bonds, adhesive bonds made in accordance with this Offenlegungsschrift are extremely hydrolysis-labile in the aqueous environment of the mouth and are suitable only for short-term temporary relinings of a few days or weeks.
A better solution to the problem is described in EP 0 632 060 A1 which describes for such purposes copolymers that are prepared by copolymerisation of methacrylates with vinyl- or allyl-methacrylates, hydrogen silicones having an adequate SiH content then being linked to free vinyl or allyl groups with the aid of a platinum catalyst.
Solutions of such SiH-group-containing copolymers, after being applied to the surface of a prosthesis, are likewise able to react with and become bonded to a vinyl silicone layer applied thereto. The hydrogen siloxane units are linked to the polymer chain structures via ester groups —CO—O—, have better resistance to hydrolysis and are therefore effective over a longer period of time as promoters of adhesion between the material of the prosthesis and the applied silicone, even in the aqueous environment of the mouth. The preparation process is a multiple-step procedure and is therefore inconvenient and expensive and the polymers prepared have acid-and base-sensitive ester groups.
The accompanying patent application DE 199 05 224.7 describes as a better solution very hydrolysis-resistant SiH-group-containing copolymers that have proved to be very effective adhesion promoters for the relining of protheses with addition-crosslinking silicones and additionally also have excellent properties when they are used as impression tray adhesives for addition-crosslinking silicone impression materials.
The above-mentioned adhesives of patent specification EP 0 632 060 A1 and the more advanced adhesives of patent application DE 199 05 224.7 have proved satisfactory as adhesives with potentially high adhesive strengths. They can be used effectively, however, only for the adhesive bonding of addition-crosslinking vinyl silicones.
Similar questions and problems also apply, however, to a broad product range of condensation-crosslinking silicones. Here too it would be desirable to find similarly effective adhesive bonding systems.
SUMMARY OF THE INVENTION
The invention is a new type of hydrolysis-resistant materials that, especially when used in the form of a solution, result in lastingly stable, moisture-resistant adhesion behavior between prosthesis material and non-hardening condensation-crosslinking silicone relining and also optionally between the material of an impression tray and the condensation-crosslinking silicone impression material.
In other words, the invention provides materials that, especially when used in the form of a solution, bring about a strong adhesive action between prosthesis material and condensation-crosslinking silicones and that are able to act as lastingly stable, moisture-resistant adhesives between prosthesis material and non-hardening silicone relinings of condensation-crosslinking silicones and also as strong impression tray adhesives for condensation-crosslinking silicone impression materials.
DISCLOSURE OF THE INVENTION
There are disclosed according to the invention copolymers having repeating structural units a) of the formula
and b) of the formula (II)
In the preceding formulae m and p are each, independently of the one another, whole numbers >0; n=1; o=1 or 0; Y is a bond or a group of the formula —CR
2
— or —CO—O—CR
2
—CR
2
—CR
2
—; each of the radicals R, independently of one another, is a hydrogen atom, an alkyl group, a group of the formula —CR′
2
—OR′, —OR′, —COOR′, —SiR
c
,R
d
,R
e
, —NR
d
—R
c
, an organic acid radical, its anhydride or its corresponding readily hydrolysable ester of the formula —O—CO—R
c
or its corresponding readily hydrolysable amide of the formula —NR
d
—CO—R
c
, a phenyl group optionally substituted by one or two —CR′═CR′
2
groups, or a group of the formula —CR
e
,R
f
CHR
g
—SiX
3
, a group of the formula —SiOSiO(SiO)
m
H, an epoxy group, an aziridine group, a phosphate or phosphorate group or an anhydride thereof or a bond, or two radicals R together represent a group of the formula ═CR2; and each of the radicals R′, R
c
, R
d
, R
e
, R
f
, R
g
and X independently of the others may be a hydrogen atom, an OH group, an alkyl group, an alkoxy group or an aryl group; with the proviso that in at least one unit of the formula II at least one radical R bonded to a Si atom is a —OH, —OR
c
, or —NR
d
R
c
group or a radical of the formula —OCOR
c
, or —NR
d
COR
c
.
Preferably the radicals R, R
c
, R
d
, R
e
, R
f
, R
g
and X are independently of one another, H atoms, OH, methyl, ethyl, methoxy or ethoxy groups. Preferably at least one unit of the formula I and one unit of the formula II are linked to one another via C—Si bonds and/or via —OCO— bonds.
The alkyl groups mentioned are substituted or unsubstituted, branched or unbranched and have preferably from 1 to 12, more preferably from 1 to 6 and most preferably 1, 2 or 3 carbon atoms. The aryl groups mentioned are substituted or unsubstituted and have 1, 2, 3 or 4 condensed aromatic rings. As substituents there are defined according to the invention e.g. branched or unbranched groups having 1, 2, 3 or 4 carbon atoms, —NO
2
, —CN, —NH
2
, —COOH, vinyl, allyl or —CONH
2
Engelbrecht Jürgen
Kix Martin
Frommer & Lawrence & Haug LLP
Michl Paul R.
S & C Polymer
Santucci Ronald
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