Dental materials based on substituted iminooxadiazine dione...

Details Dental materials based on substituted iminooxadiazine dione... Dental materials based on substituted iminooxadiazine dione...

2003-02-10

2004-11-16

Gorr, Rachel (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From reactant having at least one -n=c=x group as well as...

C525S131000, C523S109000, C522S167000

Reexamination Certificate

active

06818725

ABSTRACT:

The present invention relates to dental materials which contain substituted iminooxadiazine dione derivatives.
Varnishes and dyes based on isocyanates have been long known. These cure by polyaddition of a diol, such as 1,4-butylene glycol, to a diisocyanate, such as hexamethylene diisocyanate, accompanied by development of polyurethanes. The use of isocyanates in dental materials is likewise known. Here the isocyanates are often combined with (meth)acrylates, so that a two-phase curing of the material by diisocyanate polyaddition and radical polymerization is possible. In this way the dental material can be initially pre-cured by polyurethane formation after introduction into the patient's mouth and modeled in the initially cured state and any resulting excess can be easily removed before it is then finally cured by radical polymerization.
It has been shown however that technically significant diisocyanates, such as e.g. hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI) and bis-(4-isocyanatocyclohexyl)-methane (H
12
MDI), both in monomeric and in oligomeric form, i.e. for example in the form of trimers, are often sensitive to temperature and moisture. In addition, the oligomeric forms mostly have high viscosities which make their further processing difficult. Dental materials often contain for example a greater or lesser filler proportion, which has to be homogeneously worked into the material in order to achieve the most uniform properties possible. The incorporation of the filler is made difficult by viscous monomers. In addition, the filler content is limited in the case of high viscosity so that an adaptation of the properties of the material to the desired application purpose is possible only to a limited extent.
The object of the invention is to make dental materials available which are insensitive to moisture and whose filler content can accordingly be matched exactly to the requirements.
This object is achieved by dental materials which contain at least one iminooxadiazine dione derivative and at least one hydroxyl compound with at least two OH groups. By iminooxadiazine dione derivatives are meant derivatives of 6-imino-1,3,5-oxadiazine-2,4-dione, which have at least 2, preferably at least 3 free isocyanate groups.
Dental materials are preferred which contain at least one iminooxadiazine dione derivative with the formula
in which R is a C
1
to C
16
alkyl, C
1
to C
16
cycloalkyl and/or C
1
to C
16
alkylcycloalkyl radical which has 1 to 4, preferably 1 to 2, most preferably 1 isocyanate group.
The preferred iminooxadiazine dione derivatives are asymmetric trimers of diisocyanates which form when three diisocyanate monomers each combine via an isocyanate group and the second isocyanate group is retained. The substituted 6-imino-1,3,5-oxadiazine-2,4-diones used according to the invention are therefore also called diisocyanate trimers in the following, for the sake of simplicity.
By alkylcycloalkyl radicals are meant groups which contain both alkyl and cycloalkyl radicals. Alkyl, cycloalkyl and alkylcyclalkyl radicals with 4 to 14 and in particular 6 to 13 carbon atoms are preferred. Quite particularly preferred iminooxadiazine dione derivatives are the asymmetric trimers of hexamethylene diisocyanate. By diisocyanate trimers according to the invention are preferably meant compounds which are formed by three identical monomers.
Further iminooxadiazine dione derivatives preferred according to the invention and their preparation are described in DE 196 11 849 A2, DE 197 34 048 A2 and by Richter and Mertes, Farbe & Lack 106 (9/2000) pages 60 ff.
The iminooxadiazine dione derivatives used according to the invention can be cured like the monomeric compounds by isocyanate polyaddition and show an isocyanate reactivity comparable with the symmetric diisocyanate trimers. By the symmetric trimers are meant the corresponding isocyanuric acid derivatives which have a symmetric arrangement of ring atoms and substituents.
The iminooxadiazine dione derivatives and in particular the asymmetric diisocyanate trimers are characterized compared with the symmetric trimers by a clearly increased moisture—and temperature—stability and a lower viscosity.
For example, the viscosity of the asymmetric trimer of hexamethylene diisocyanate (R═—(CH
2
)
6
—NCO) is lower by a factor of two than the viscosity of the corresponding symmetric trimer. The lower viscosity facilitates the incorporation of filler into the material and simultaneously allows the use of higher filler amounts.
The iminooxadiazine dione derivatives preferred according to the invention have a viscosity of <2000 mPas, preferably of <1500 mPas and particularly preferably roughly 1000±200 mPas. Unless stated otherwise, the viscosity is measured according to DIN EN 3219/A3.
The dental materials according to the invention preferably contain at least 5 to 50 wt.-%, particularly preferably 7 to 40 wt.-% and quite particularly preferably 9 to 30 wt.-% of the asymmetric trimer, relative to the total mass of the material.
The dental materials according to the invention contain, as further component, at least one hydroxyl compound which, together with the iminooxadiazine dione derivative, forms a polyurethane by diisocyanate polyaddition.
Polyols in particular are suitable as hydroxyl compounds. By polyols are meant compounds with 3 and more hydroxyl groups, the term hydroxyl group referring to alcoholic OH groups. Monomeric or polymeric aliphatic, alicyclic or aromatic compounds with 3 to 6 OH groups are particularly preferred.
Among the hydroxyl compounds with three OH groups, trimethylolethane, trimethylolpropane, trimethylolbutane, glycerol and the low-molecular adducts of ethylene and/or propylene oxide to the named compounds are to be emphasized as particularly suitable.
Preferred hydroxyl compounds with four OH groups are pentaerythritol and di-trimethylolpropane.
A preferred hydroxyl compound with six OH groups is di-pentaerythritol.
Furthermore aliphatic and/or cycloaliphatic diols can also be used, e.g. ethylene glycol, di- and triethylene glycol, 1,2- and 1,3-propanediol, di- and tripropylene glycol, 1,2 and 1,3 or 1,4 butanediol, 1,6 hexanediol, 2-methylpentanediol, neopentyl glycol, cyclohexanediol and dimethylolcyclohexane.
Preferred polymeric polyols are polyester polyols, polyether polyols and polyalcohols which contain both ester and ether groups, hydroxyl compounds being particularly preferred which have an equivalent weight of 50 to 1000, particularly preferably 70 to 400 per hydroxyl group. Among the polymer polyols, compounds are furthermore preferred which have a branched structure.
Particularly suitable for the preparation of the dental materials according to the invention are hydroxyl compounds which, in addition to the hydroxyl groups, contain radically polymerizable groups and thus facilitate a cross-linking of the polyurethane chains formed by the diisocyanate polyaddition by radical polymerization. Vinyl, methacryl and/or acryl groups in particular can be considered as polymerizable groups.
The preferred hydroxyl compounds with radically polymerizable groups include the hydroxyethyl (meth)acrylates, such as e.g. 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate and 4-hydroxybutyl methacrylate.
A mixture of the abovementioned hydroxyl compounds can also be advantageously used as hydroxyl component, preferably a mixture of monomeric and polymeric hydroxyl compounds. A preferred mixture contains 28 to 38 wt.-%, preferably 30 to 36 wt.-% monomeric hydroxyl compound, in particular trimethylolpropane, and 62 to 72 wt.-%, preferably 64 to 70 wt.-% polymeric hydroxyl compound, in particular polyesters containing hydroxyl groups and/or polyalcohol containing ester and ether groups, the polymer components having a branched structure according to a further preferred version.
The hydroxyl compound content of the dental materials is based primarily on the amount of iminooxadiazine dione derivative. A content of 4 to 40 wt.-%, p

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