(Meth)acrylic esters and their use.

The invention relates to new fluorine-containing acrylic and methacrylic acid esters, hereinafter called (meth) acrylic acid esters, and their preparation. The new compounds can be used as monomers for use in the dental field.

Fluorine-containing phenylcarbinol acrylates such as 1,1,1,3,3,3-hexafluoro-2-phenyl-2-acryloxypropane are from Org. Coat. Plastic. Chem. 42, 204-207, (1980). Similar (meth) acrylic esters, such as 1,3-bis (2- (meth) acrylic-oxy-1,1,1,3,3,3-hexafluoropropyl-2) -5-perfluoroalkyl-benzene and their use the dental field are described in US 4,356,296. The carbinols are acidified by the trifluoromethyl groups and the carbinol esters produced therefrom are distinguished by a reduced resistance to hydrolysis. This limits their usability as dental monomers.

Furthermore, the use of 1,1,5-trihydro-octafluoropentyl methacrylate in dental filling materials in J. Dent. Res. 58, 1181-1186 (1979).

Monomers of this type provide dental materials with insufficient mechanical properties.

There were new (meth) acrylic acid esters of the formula<chemistry id="chem0001" num="0001"><img file="EP0201031A2_D0001.tif" /></chemistry>in the<ul id="ul0001" list-style="none"><li>R¹ and R² are the same or different and are hydrogen, chlorine, fluorine or a C₁- to C₄-Alkylrest mean and</li><li>R³ and R⁴ are the same or different and for the group<chemistry id="chem0002" num="0002"><img file="EP0201031A2_D0002.tif" /></chemistry>or<chemistry id="chem0003" num="0003"><img file="EP0201031A2_D0003.tif" /></chemistry>stand where</li><li>R⁵ and R⁶ are identical or different and represent a hydrogen atom or a methyl group,</li><li>Z is a straight-chain or branched C₂- to C₈-Alkylene chain means and</li><li>n means values ​​from 1 to 4,</li></ul>found.

The new (meth) -acrylic acid esters are colorless, non-volatile and, after polymerisation, result in transparent plastics.

They can be used particularly well in sealants, adhesives and dental materials, such as dental fillings and coating materials. The materials obtained in this way are characterized by great resistance to physical and chemical stress. Of particular note are the favorable surface properties and low water absorption of the polymers obtained with the new (meth) acrylic acid esters.

In the context of the present invention, the substituents can generally have the following meaning.

AC₁- to C₄Alkyl radical generally means a straight-chain or branched hydrocarbon radical. Examples include methyl, ethyl, propyl, isopropyl, butyl and isobutyl. The methyl radical is preferred.

AC₂- to C₈Alkylene chain generally means a straight-chain or branched double-bonded hydrocarbon chain. Examples include ethylene, propylene, iso-propylene, butylene, iso-butylene, pentylene, iso-pentylene, hexylene, iso-hexylene, heptylene, iso-heptylene, octylene and iso-octylene.

Preferred (meth) acrylic acid esters are compounds of the formula<chemistry id="chem0004" num="0004"><img file="EP0201031A2_D0004.tif" /></chemistry>in the<ul id="ul0002" list-style="none"><li>_R³ and R⁴ are the same or different and for the groups<chemistry id="chem0005" num="0005"><img file="EP0201031A2_D0005.tif" /></chemistry>or<chemistry id="chem0006" num="0006"><img file="EP0201031A2_D0006.tif" /></chemistry>stand where</li><li>R⁵ and R⁶ are identical or different and represent a hydrogen atom or a methyl group,</li><li>Z is a straight-chain or branched C₂- to C₈-Alkylene chain means and</li><li>n means values ​​from 1 to 4.</li></ul>

The substituents R³ and R⁴ can preferably be in the 3,3'- or 3,4'- or 4,4'-position in the 1,2-diphenyl-tetrafluoroethane. Compounds with R³ and R⁴ in the 4,4'-position.

For example, the following (meth) acrylic acid esters may be mentioned:<tables id="tabl0001" num="0001"><img file="EP0201031A2_D0007.tif" /></tables><tables id="tabl0002" num="0002"><img file="EP0201031A2_D0008.tif" /></tables>

A process for the preparation of the new (meth) -acrylic acid esters was also found. The production process is characterized in that a 1,2-bis (fluorophenyl) -1,1,2,2-tetrafluoroethane of the formula<chemistry id="chem0007" num="0007"><img file="EP0201031A2_D0009.tif" /></chemistry>in the<ul id="ul0003" list-style="none"><li>R¹ and R² are the same or different and are hydrogen, chlorine, fluorine or a C₁- to C₄-Alkylrest mean</li><li>with α, ω-dihydroxy compounds of the formula<chemistry id="chem0008" num="0008"><img file="EP0201031A2_D0010.tif" /></chemistry>in the</li><li>n values ​​from 1 to 4 and</li><li>R⁵ Means hydrogen or methyl,</li></ul>etherified in the presence of a strong base and the reaction product esterified with (meth) acrylic acid and / or its reactive derivatives or reacted with isocyanatoalkyl (meth) acrylates.

Compounds of the formula III are, for example, according to LM Yagupolskii, VI Troitskaya, Zh. Obshch. Khim. 35. (9), 1620 (1965) and J. Gen. Chem. USSR 35, 1616 to 1623 (1965) accessible.

α, ω-dihydroxy compounds can be, for example, ethylene glycol, propylene glycol, diethylene glycol or triethylene glycol.

Reactive derivatives of (meth) acrylic acid are, for example, the acid halides, preferably the chlorides and esters, preferably esters of lower alcohols.

The oxyalkylation of the compounds III with the α, ω-dihydroxy compounds described above is carried out in the presence of strong bases in the temperature range from 50 to 180 ° C., preferably 100 to 160 ° C.

Strong bases can be a PK according to the invention_BHave a value of less than 3, preferably less than 2, particularly preferably less than 0. Examples include potassium tert-butoxide, sodium and potassium isopropoxide.

The products are isolated, for example, by pouring the reaction mixture onto ice water and suctioning off the precipitated crystals or, in the case of liquid products, extracting them with a water-insoluble solvent.

The intermediates obtained by the oxyalkylation have the general formula<chemistry id="chem0009" num="0009"><img file="EP0201031A2_D0011.tif" /></chemistry>in the<ul id="ul0004" list-style="none"><li>R¹ and R² have the meaning mentioned above,</li><li>R⁵ Hydrogen or a methyl group and</li><li>n means values ​​from 1 to 4.</li></ul>

The number of attached oxyalkylene units (n) is variable within wide limits.

N can preferably assume the values ​​1 or 2.

Hydroxyl compounds of the formula have proven to be particularly advantageous<chemistry id="chem0010" num="0010"><img file="EP0201031A2_D0012.tif" /></chemistry>in the<ul id="ul0005" list-style="none"><li>n assumes values ​​from 1 to 4 and</li><li>R⁴ represents a hydrogen atom or a methyl group.</li></ul>

The (meth) acrylic acid esters (I) according to the invention are obtained from the hydroxyl compounds of the formula (V) by esterification or by reaction with isocyanatoalkyl (meth) acrylates.

For the esterification, (meth) acrylic acid, (meth) acrylic acid chloride, (meth) acrylic acid anhydride or (meth) acrylic acid esters of lower alcohols can be used. The esterification is preferably carried out with (meth) acrylic acid in the presence of an acid catalyst, for example p-toluenesulfonic acid, sulfuric acid or ion exchangers in the H^e-Form in a solvent that is immiscible with water, for example toluene, chloroform xylene, etc.

The esterification can be carried out, for example, as follows:<ul id="ul0006" list-style="none"><li>The hydroxyl compound and an excess of (meth) acrylic acid are suspended or dissolved in a solvent, and the acidic catalyst and a polymerization inhibitor are added. The water formed during the esterification is removed from the equilibrium by azeotropic distillation. The reaction is generally carried out in the temperature range from 50 ° C. to about 120 ° C. (boiling point of the azeotropic mixture about 100 ° C.).</li></ul>

Suitable polymerization inhibitors are, for example, 2,6-di-tert-butyl-4-methylphenol, methylene blue and hydroquinone in an amount of 0.01 to 1% by weight. After the esterification has ended, unreacted (meth) acrylic acid is removed by extraction with a basic aqueous solution. The inhibitor is separated off, for example, by adding adsorbents. The reaction products according to the invention are isolated by distilling off the solvents.

Isocyanates of the formula are preferably suitable for reacting the hydroxyl compounds of the formula V with isocyanatoalkyl (meth) acrylates:<chemistry id="chem0011" num="0011"><img file="EP0201031A2_D0013.tif" /></chemistry>in which<ul id="ul0007" list-style="none"><li>Z is a straight-chain or branched C₂- to C₈-Alkylene chain and</li><li>R⁶ represents a hydrogen atom or a methyl group. Suitable isocyanatoalkyl (meth) acrylates are 2-isocyanatoethyl methacrylate, 2-isocyanatopropyl methacrylate and 1,2-dimethyl-3-isocyanatopropyl acrylate.</li></ul>

The conversion to urethane is preferably carried out with the exclusion of water in an inert solvent. Examples of suitable solvents are: chloroform, tetrahydrofuran, dioxane, methylene chloride, toluene and acetonitrile. Preferred solvents are chloroform, tetrahydrofuran and acetonitrile.

The reaction is generally carried out in the temperature range from 20 to 100 ° C., preferably 30 to 70 ° C. Catalysts containing tin, such as dibutyltin dilaurate or tin (II) octoate, are preferably used to accelerate the reaction. Other suitable catalysts are compounds with tert. Amino groups and titanium compounds. In general, the catalyst is used in an amount of 0.01 to 2.5% by weight, preferably 0.1 to 1.5% by weight, based on the total amount of the reactants.

The conversion to the urethane is generally carried out in the presence of 0.01 to 0.2% by weight of a polymerization inhibitor, for example 2,6-di-tert-butyl-4-methylphenol, at atmospheric pressure. However, it is also possible to carry out the method according to the invention at a negative or positive pressure.

The reaction can be carried out, for example, as follows:<ul id="ul0008" list-style="none"><li>An isocyanatoalkyl (meth) acrylate (VII) and a hydroxyl compound (V) are dissolved or suspended in the solvent and the catalyst is added with stirring.</li></ul>

After the addition of the polymerization inhibitor, the reaction solution is heated to a temperature between 20 and 100 ° C.

The time course of the implementation can be followed, for example, by measuring the IR spectra. After the isocyanate groups have reacted completely, the reaction products are isolated by removing the solvent. Prior cleaning with the aid of adsorbents, for example activated carbon, bleaching earth, silica gel or aluminum oxide, is possible.

For use as monomers for dental filling compounds or coating compositions (dental lacquers) in the dental field, the (meth) acrylic acid esters of the formula 1 according to the invention can be mixed with monomers known per se, for example in order to adapt the viscosity to the intended use. Viscosities in the range from 60 to 10,000 mPas are preferred. This can be achieved by optionally adding a comonomer of lower viscosity as a reactive diluent to the monomers according to the invention. The compounds according to the invention are used in a mixture with comonomers in a proportion of approximately 30 to approximately 90% by weight, a proportion of 50 to 90% by weight being particularly preferred.

In the context of the present invention, it is also possible to use mixtures of various (meth) acrylic acid esters according to the invention.

It is also possible to use monomer mixtures which contain several comonomers as reactive diluents.

For example, the following comonomers are mentioned:<ul id="ul0009" list-style="none"><li>Triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,12-dodecanediol dimethacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol dimethacrylate, (meth) acrylic acid ester of ethoxylated or propoxylated hydroxyl-containing tricyclo [5.2.1.0^2,6] decane derivatives (cf. DE-OS 2 931 925 and 2 931 926). In particular, comonomers are preferred which have a boiling point above 100 ° C. at 13 mbar.</li></ul>

The (meth) -acrylic acid esters according to the invention can be cured, if appropriate in a mixture with the monomer mentioned, using methods known per se (GM Brauer, H. Argentar, Am. Chem. Soc., Symp. Ser. 212, S 359-371 ( 1983)). A system consisting of a peroxidic compound and a reducing agent, for example based on tertiary aromatic amines, is suitable for the so-called redox polymerization, the peroxide-containing and amine-containing monomer mixture having to be stored separately until use in order to prevent premature polymerization.

Examples of suitable peroxides are:<ul id="ul0010" list-style="none"><li>Dibenzoyl peroxide, dilauroyl peroxide and di-chlorobenzoyl peroxide.</li></ul>

Examples of tertiary aromatic amines are N, N-dimethyl-p-toluidine, bis- (2-hydroxyethyl) -p-toluidine, bis (2-hydroxyethyl) -3,5-dimethylaniline, and that in DE-PS 2,759,239 N-methyl-N- (2-methylcarbamoyl-oxypropyl) -3,5-dimethylaniline described.

The concentration of the peroxide or of the amine is advantageously chosen such that it is 0.1 to 5% by weight, preferably 0.5 to 3% by weight, based on the monomer mixture.

The monomers according to the invention can also be brought to polymerization by irradiation with UV light or visible light (for example in the wavelength range from 230 to 650 nm).

It is a one-component system. The advantage over redox-curing two-component systems is that the curing of the monomer mixture is not impaired by inhomogeneities which can be caused in the redox system by inadequate mixing of the two components.

Suitable initiators for the photo-initiated polymerization are, for example, benzil, benzil dimethyl ketal, benzoin monoalkyl ether, benzophenone, p-methoxybenzophenone, fluorenone, thioxanthone, phenanthrenequinone and 2,3-bornanedione (camphorquinone), optionally in the presence of synergistic photoactivators such as N, N-methacrylate , Triethanolamine, 4-N, N-dimethylaminobenzenesulfonic acid bisallylamide. The implementation of the photopolymerization process is described for example in DE-PS 3 135 115.

In addition to the initiators described above, light stabilizers and polymerization inhibitors known per se for this purpose can be added to the (meth) acrylic acid esters according to the invention.

The light stabilizer and the polymerization inhibitor are generally used in an amount of 0.01 to 0.50 parts by weight, based on 100 parts by weight of the monomer mixture. The monomer mixtures can be used as coatings (tooth varnishes) without the addition of fillers.

When used as tooth filling compounds, fillers are generally added to the monomer mixtures obtained. In order to be able to achieve a high degree of filling, monomer mixtures which have a viscosity in the range from 60 to 10,000 mPas are particularly advantageous. The monomer mixtures containing the compounds of the formula I according to the invention can preferably be admixed with inorganic fillers. For example, rock crystal, quartzite, crystallobalite, quartz glass, finely divided silica, aluminum oxide and glass ceramics, for example glass ceramics containing lanthanum and zircon (DE-OS 23 47 591) may be mentioned.

To improve the bond to the polymer matrix of the polymethacrylate, the inorganic fillers are preferably pretreated with an adhesion promoter. Adhesion can be achieved, for example, by treatment with organosilicon compounds (Plueddemann, Progress in Organic coatings, 11, 297 to 308 (1983)). 3-methacryloyloxypropyltrimethoxysilane is preferably used.

The fillers for the dental filling compositions according to the invention generally have an average particle diameter of 0.01 to 100 μm, preferably 0.05 to 50 μm, particularly preferably 0.05 to 5 μm. It can also be advantageous to use several fillers next to one another which have a different particle diameter.

The proportion of the (meth) -acrylic acid esters according to the invention in the filling materials is generally 5 to 85% by weight, based on the filling material.

The filler content in the tooth filling materials is generally 5 to 85% by weight, preferably 50 to 80% by weight.

For the production of the tooth filling compounds, the components are processed using kneading machines known per se.

Manufacturing examples

example 1

<ul id="ul0011" list-style="none"><li>A) Preparation of 1,2-bis [4- (2-hydroxyethoxy) phenyl] -1,1,2,2-tetrafluoroethane<chemistry id="chem0012" num="0012"><img file="EP0201031A2_D0014.tif" /></chemistry>700 ml of ethylene glycol and 65 g of 1,2-bis (4-fluorophenyl) -1,1,2,2-tetrafluoroethane^* are heated to 110 ° C in a stirred flask. 57 g of potassium tert-butoxide are added in portions and the mixture is then stirred at 150 ° C. for 7 hours. The mixture is cooled, poured onto 4 l of ice water and mixed with a homogenizer (Ultraturax). The precipitated crystals are filtered off with suction, stirred again with 2 l of water, filtered off again, dried and recrystallized from toluene. Yield: 39 g. Melting point: 124-127 ° C. The 1 H NMR spectrum shows the structure given above.</li><li>B) Preparation of 1,2-bis [4- (2-hydroxyethoxyethoxy) pheny] -1,1,2,2-'tetrafluoroethane<chemistry id="chem0013" num="0013"><img file="EP0201031A2_D0015.tif" /></chemistry>700 ml diethylene glycol and 65 g 1,2-bis (4-fluorophenyl) -1,1,2,2-tetrafluoroethane^* are heated to 130 ° C. in a stirred flask and 57 g of potassium tert-butoxide are added in portions. The mixture is then heated to 150 ° C and stirred at this temperature for 2 hours. The mixture is cooled, poured onto 4 l of ice water and mixed with a homogenizer (Ultraturax) until crystals precipitate. The precipitate is filtered off, stirred again with 3 1 of water, acidified with hydrochloric acid, suction filtered, dried and recrystallized from toluene. Yield: 70 g Melting point: 94-95 ° C The integrated ¹H-NMR spectrum actuates the structure given above ^* Chem. Abstr. Reg. NO [4100-99-6]</li></ul>

Example 2 (4,4'-isomer of compound 1 from Table 1)

Preparation of 1,2-bis- [4- (2-methacryloyloxyethoxy) phenyl] -1,1, -2,2-tetrafluoroethane<ul id="ul0012" list-style="none"><li>37.4 g (0.1 mol) of 1,2-bis- [4- (2-hydroxyethoxy) phenyl] -1,1,2,2, -tetrafluoroethane</li><li>25.8 g (0.3 mol) methacrylic acid</li><li>1 g p-toluenesulfonic acid and</li><li>0.3 g methylene blue</li></ul>

are suspended in 100 ml of toluene. At 110 ° C the water is removed by azeotropic distillation, air being passed through the suspension. When the water separation is complete, the mixture is stirred with bleaching earth, filtered off with suction and the filtrate is extracted with sodium bicarbonate solution. The organic phase is stirred with pulp flour and suction filtered. It is then washed neutral with sodium chloride solution. The organic phase is dried over sodium sulfate and freed from the solvent in vacuo.<ul id="ul0013" list-style="none"><li>Yield: 39.3 g (77%)</li><li>Melting point: 84 to 85 ° C</li><li>GC analysis: 97%</li></ul>

Example 3 (4,4'-isomer of compound 2 from Table 1)

Preparation of 1,2-bis- [4- (2-methacryloyloxy-ethoxy-ethoxy) phenyl III, 1,2,2-tetrafluoroethane<ul id="ul0014" list-style="none"><li>46.2 g (0.1 mol) of 1,2-bis- [4- (2-hydroxyethoxyethoxy) phenyl) 1,1,2,2-tetrafluoroethane</li><li>25.8 g (0.3 mol) methacrylic acid</li><li>1 g p-toluenesulfonic acid and</li><li>0.3 g of methylene blue are in</li><li>150 ml of toluene suspended.</li></ul>

With the introduction of air, the water of reaction is continuously removed for 24 hours. When the reaction is complete, the mixture is stirred with bleaching earth, suction filtered and the filtrate is extracted with sodium bicarbonate solution. The organic phase is stirred with pulp flour and suction filtered. It is then washed neutral with sodium chloride solution. The toluene phase is dried over sodium sulfate and freed from the solvent in vacuo.

Yield: 53.5 g (89.5%) Melting point: 64 to 66 ° C ¹H-NMR (CDC1₃) [ppm]: 1.95 (-CH₃, 6H), 4.5 - 3.7 (-CH₂-, 16H), 5.5 - 5.65 and 6.2 - 6.05 (= CH₂, 4H), 6.75 - 7.5 (1,4-disubstituted phenyl radical, 8H)

Example 4 (4,4'-isomer of compound 6 from Table 1)

Preparation of 1,2-bis [4- (2-methacryloyloxyethyl-carbamoyloxy-ethoxyethoxy) phenyl] -1,1,2,2-tetrafluoroethane 4.62 g (10 mmol) of 1,2-bis- [4- (2nd -Hydroxyethoxyethoxy) -phenyl] -1,1,2,2-tetrafluoroethane are dissolved in 30 ml of chloroform.

0.03 g of stannous octoate and 0.003 g of 2,6-di-tert-butyl-4-methylphenol are added. 3.1 g (20 mmol) of 2-isocyanatoethyl methacrylate are slowly added dropwise at room temperature. After the addition of the isocyanate has ended, the reaction mixture is stirred at 50 ° C. until the IR absorption of the NCO band at 2200 cm^-1 has disappeared (about 5 hours reaction time). The product is isolated by removing the solvent in vacuo. The urethane is a colorless, viscous liquid that becomes crystalline after several days when it cools below 10 ° C.

Yield: 7.6 g (98.4%). The expected structure was confirmed by the ¹H-NMR spectrum confirmed.

Example 5 (4,4'-isomer of compound 8 from Table 1)

Preparation of 1,2- [4- (2-methacryloyloxyethoxyethoxy) -4 '- (2-acryloyloxyethoxyethoxy)] - diphenyl-1,1,2,2-tetrafluoroethane<ul id="ul0015" list-style="none"><li>46.2 g (0.1 mol) 1,2-bis- [4- (2-hydroxyethoxyethoxy) phenyl] -1,1,2,2-tetrafluoroethane</li><li>12.9 g (0.15 mol) methacrylic acid</li><li>10.8 g (0.15 mol) acrylic acid</li><li>1 g p-toluenesulfonic acid and</li><li>0.3 g methylene blue</li></ul>are suspended in 250 ml of toluene and heated under reflux for 24 hours.

The reaction and working up are carried out analogously to Example 3. After complete removal of the solvent, the monomer is a colorless, viscous liquid.

Yield: 51.7 g

Application examples:

Example 6

Manufacture of coating solutions

a) redox curing system

In a solution of the monomer mentioned in Example 5 (80 parts by weight) and triethylene glycol dimethacrylate (20 parts by weight), 2.00% by weight di-benzoyl peroxide and 0.04% by weight 2,6-di -ter-butyl-4-methylphenol dissolved.

2.2% by weight of N-methyl-N- (2-methylcarbamoyloxypropyl) -3,5-dimethylaniline are dissolved in a second mixture which contains no peroxide but is otherwise composed in the same way.

A mixture of equal parts of the two solutions described above hardens in 2 to 3 minutes.

b) light curing system

In a monomer mixture of 80 parts by weight of monomer from Example 5 and 20 parts by weight of triethylene glycol dimethacrylate, 0.5% by weight of 4-N, N-dimethylaminobenzenesulfonic acid-bis-allylamide, 0.125% by weight of benzil dimethyl ketal, 0 , 2 wt% bicyclo [2,2,1] -1,7,7-trimethyl-heptane-2,3-dione (2,3-bornanedione) and 0.04 wt% 2,6-di - Dissolved tert-butyl-4-methylphenol.

The liquid hardens when exposed with a dental lamp (exposure time 40 seconds).

Example 7

Example 6 was repeated using the monomer from Example 4.

The cured coating solutions from Examples 6 and 7 are transparent and have a high hardness.

Example 8

Production of a redox-curing dental compound

Amine paste: In a monomer mixture of 80 parts by weight of the compound according to the invention from Example 5 and 20 parts by weight of triethylene glycol dimethacrylate, 2.2% by weight of N-methyl-N- (2-methylcarbamoyloxypropyl) -3,5-dimethylaniline and 0.04% by weight .-% of the polymerization inhibitor from Example 6 dissolved. 5 g of this solution are processed into a paste with 15 g of a commercially available glass ceramic with an average particle diameter of 4 μm, which was silanized with 3-methacryloyloxypropyltrimethoxysilane.

Peroxide paste: 2.0 parts by weight of dibenzoyl peroxide are dissolved in a mixture of 80 parts by weight of the compound according to the invention from Example 5 and 20 parts by weight of triethylene glycol dimethacrylate. 5 g of this solution are processed into a paste with 15 g of a commercially available glass ceramic with an average particle diameter of 4 μm, which was silanized with 3-methacryloyloxypropyltrimethoxysilane.

A mixture of equal parts of amine paste and peroxide paste hardens within 2 to 3 minutes.

Example 9

Production of a light-curing tooth filling material

In a mixture of 80 parts by weight of monomer from Example 5 and 20 parts by weight of triethylene glycol dimethacrylate, 0.2% by weight of 2,3-bornanedione, 0.125% by weight of benzil dimethyl ketal, 0.5% by weight of X 4-N, N-dimethylamino benzenesulfonic acid bis-allylamide and 0.04% by weight of 2,6-di-tert-butyl-4-methylphenol.

5 g of this solution are processed with 15 g of the filler described in Example 8 into a paste (75% filler content).

The curing takes place by exposure with a dental lamp. With an exposure time of 40 seconds, the curing depth is 6.1 mm.

Example 10

Example 9 was repeated using the compound from Example 4.

Example 11

Measurement of solid surface tensions

Surface tension measurements were carried out on the cured coating composition from Example 6. The dynamic wetting behavior of liquids on the solid surfaces was determined using a video system. The surface tensions were calculated from the initial contact angles of 5 test liquids. The results are summarized in Table 2.<tables id="tabl0003" num="0003"><img file="EP0201031A2_D0016.tif" /></tables>