Silane and silicic acid (hetero)polycondensate having aromatic compounds linked via coupling groups which are suitable as or for matrix systems having high translucency and good mechanical properties

Abstract

The present invention relates to compounds and silicic acid (hetero)polycondensates comprising structures of formulas (1) and/or (2), ##STR00001## R.sup.2 is a hydroxy group or a free carboxylic acid residue or a carboxylic acid ester derived therefrom or a salt derived therefrom, R.sup.3 denotes a residue having a hydrocarbon-containing branched or unbranched backbone which is bonded to silicon by carbon, and can be arbitrarily interrupted by heteroatoms or coupling groups or by other heteroatom-containing groups, where the zigzag line purely schematically denotes the hydrocarbon-containing backbone, the three not more closely characterized bonds of the Si-atom represent additional residues bonded to the silicon atom, selected from residues that can be hydrolyzed from silicon, hydroxy groups and residues bonded to silicon by carbon which can have the same meaning as R.sup.3 or can have a different meaning deviating therefrom, or represent oxygen bridges to further silicon atoms and/or other metal atoms in the case the structure (1) is part of a silicic acid (hetero)polycondensate, the residue Y is either divalent, and then has the meaning of S, NR.sup.4 or P(O)(R.sup.4).sub.c(Z).sub.d with ZOR.sup.4, c=0 or 1, d=0 or 1 and (c+d)=1, or trivalent and has the meaning of N or P(O), R.sup.4 represents a hydrocarbon-containing residue and in the NR.sup.4 residue can in addition have the meaning of hydrogen, W is a substituted or unsubstituted hydrocarbon residue bonded to Y, the chain of which can be interrupted by S, O, NH, NR.sup.4, C(O)O, NHC(O), C(O)NH, NHC(O)O, C(O)NHC(O), NHC(O)NH, S(O), C(S)O, C(S)NH, NHC(S), NHC(S)O, Ar is a residue that carries at least one aromatic group which is unsubstituted or substituted with one or more residues, where the aromatic groups do not carry substituents, selected from boronic acid-, the carboxylic acid-, the phosphine acid-, the phosphonic acid- and the sulfonic acid group and from hydroxy groups, where Ar must be bonded to W if a0, Z is selected from urethane-, acid amide-, ether- and ester groups, R.sup.1 is a straight chain or branched, organically polymerizable group carrying at least one CC double bond, and the index e is 1, 2, 3, 4 or an integer greater than 4, the index a is equal to 0 or 1 or 2, the index b=1, 2, 3 or an integer greater than 3 if a0, and b=1 or 2 if a=1, the index m is 1, 2 or an integer greater than 2, the index n is 0, 1, 2 or greater than 2 and the index o is 1 or 2 or greater than 2.
composites and organically polymerized masses produced therefrom and methods for producing the same.

Claims

1. Compound of formula (1), (2), or (3), or silicic acid (hetero)polycondensate comprising structures of formula (1), (2), or (3) ##STR00013## wherein R.sup.2 is a hydroxy group or a free carboxylic acid residue or a carboxylic acid ester derived therefrom or a salt derived therefrom, R.sup.3 denotes a residue having a hydrocarbon-containing branched or unbranched backbone which is bonded to silicon by carbon, and can be arbitrarily interrupted by heteroatoms or coupling groups or by other heteroatom-containing groups, where the zigzag line purely schematically denotes the hydrocarbon-containing backbone, the three not more closely characterized bonds of the Si-atom represent additional residues bonded to the silicon atom, selected from residues that can be hydrolyzed from silicon, hydroxy groups and residues bonded to silicon by carbon, which can have the same meaning as R.sup.3 or can have a different meaning deviating therefrom, with the proviso that in case of a compound of formula (1), (2) or (3), the residues are selected such that the silane can subsequently be subjected to hydrolytic condensation or represent oxygen bridges to further silicon atoms and/or other metal atoms if the structure (1) is part of a silicic acid (hetero)polycondensate, the residue Y is either divalent and then has the meaning of S, NR.sup.4 or P(O)(R.sup.4).sub.c(Z).sub.d with ZOR.sup.4, c=0 or 1, d=0 or 1 and (c+d)=1, or trivalent and has the meaning of N or P(O), R.sup.4 represents a hydrocarbon-containing residue and in the residue NR.sup.4 can in addition have the meaning of hydrogen, W is a substituted or unsubstituted hydrocarbon residue, the chain of which can be interrupted by S, O, NH, NR.sup.4, C(O)O, NHC(O), C(O)NH, NHC(O)O, C(O)NHC(O), NHC(O)NH, S(O), C(S)O, C(S)NH, NHC(S), NHC(S)O, Ar is a residue that carries at least one aromatic group which is unsubstituted or which is substituted with one or more residues, where the aromatic groups do not carry substituents, which are selected from boronic acid-, a carboxylic acid-, a phosphine acid-, a phosphonic acid- and a sulfonic acid group as well as from hydroxy groups, the index b=1, 2, or 3, the index m is 1, 2 or an integer greater than 2, the index n is 0, 1, 2 or greater than 2 and the index o is 1 or 2 or greater than 2, Z is selected from urethane-, acid amide-, ether- and ester groups, R.sup.1 is a straight chain or branched, organically polymerizable group carrying at least one CC double bond and e is 1, 2, 3, 4 or an integer greater than 4, W, in the case that both Z groups represent ester groups which are bonded to W via the carboxyl-carbon atom, can be a single bond and is otherwise a carbon chain optionally interrupted by oxygen atoms, sulfur atoms, carbonyl groups, carboxyl groups, amino groups or amide groups, and f=1, 2, 3, 4, 5 or 6 or greater than 6.

2. Silicic acid (hetero)polycondensate comprising structures of formula (1), (2), or (3) as claimed in claim 1, further comprising a particulate filler dispersed therein.

3. Silicic acid (hetero)polycondensate comprising structures of formula (1), (2), or (3) as claimed in claim 2, wherein the silicic acid (hetero)polycondensate and the filler have a refractive index difference .sub.nD the region of 0.001.

4. Silicic acid (hetero)polycondensate comprising structures of formula (1), (2), or (3), as claimed in claim 1, in the form of bulk materials, composites, cements, adhesives, casting compounds, coating materials, adhesion promoters, fillers, fibers, and priming materials for fillers of fibers.

5. Silicic acid (hetero)polycondensate comprising structures of formula (1), (2), or (3), as claimed in claim 2, in the form of bulk materials, composites, cements, adhesives, casting compounds, coating materials, adhesion promoters, fillers, fibers, and priming materials for fillers of fibers.

6. Compound mixture or silicic acid (hetero)polycondensate according to claim 1, comprising (i) a compound or structures as specified in formula (1) and a compound or structures of formula (2), or (ii) a compound or structures as specified in formula (1) and a compound or structures of formula (3), or (iii) a compound or structures as specified in formula (1), a compound or structure of formula (2) and a compound or structures of formula (3).

7. Compound mixture or silicic acid (hetero)polycondensate according to claim 6, further comprising a particulate filler dispersed therein.

8. Compound mixture or silicic acid (hetero)polycondensate according to claim 7, wherein the silicic acid (hetero)polycondensate and the filler have a refractive index difference .sub.nD in the region of 0.001.

9. Compound mixture or silicic acid (hetero)polycondensate according to claim 6 in the form of bulk materials, composites, cements, adhesives, casting compounds, coating materials, adhesion promoters, fillers, fibers, and priming materials for fillers of fibers.

10. Compound mixture or silicic acid (hetero)polycondensate according to claim 7 in the form of bulk materials, composites, cements, adhesives, casting compounds, coating materials, adhesion promoters, fillers, fibers, and priming materials for fillers of fibers.

11. Organically cross-linked silicic acid (hetero)polycondensate, comprising structures of formula (2) according to claim 1 in which (i) some or all of the R.sup.1 residues are cross-linked to each other via polymerization, or (ii) some or all of the R.sup.1 residues are cross-linked via Michael addition with di- or higher thiols or di- or higher amines, or (iii) some or all of the R.sup.1 residues are cross-linked to each other via polymerization, and wherein the organically cross-linked silicic acid (hetero)polycondensate further comprises structures of formula (0) ##STR00014## wherein the residues and substituents R.sup.2, R.sup.3, o and n have the same meaning as in formula (1) and R.sup.1 has the same meaning as in formula (2), with the proviso that some or all of the R.sup.1 residues are cross-linked to each other via polymerization or via Michael addition with di- or higher thiols or di- or higher amines, or with R.sup.1 residues of the structure of formula (2), or (iv) some or all of the R.sup.1 residues are cross-linked to each other via polymerization, and wherein the organically cross-linked silicic acid (hetero)polycondensate further comprises structures of formula (1), or (v) some or all of the R.sup.1 residues are cross-linked via Michael addition with di- or higher thiols or di- or higher amines, and wherein the organically cross-linked silicic acid (hetero)polycondensate further comprises structures of formula (1), or (vi) some or all of the R.sup.1 residues are cross-linked to each other via polymerization and some or all of the R.sup.1 residues are cross-linked via Michael addition with di- or higher thiols or di- or higher amines, wherein the organically cross-linked silicic acid (hetero)polycondensate further comprises structures of formula (1).

12. Organically cross-linked silicic acid (hetero)polycondensate according to claim 11, further comprising a particulate filler dispersed therein.

13. Organically cross-linked silicic acid (hetero)polycondensate according to claim 12, wherein the silicic acid (hetero)polycondensate and the filler have a refractive index difference .sub.nD in the region of 0.001.

14. Organically cross-linked silicic acid (hetero)polycondensate according to claim 11 in the form of bulk materials, composites, cements, adhesives, casting compounds, coating materials, adhesion promoters, fillers, fibers, and priming materials for fillers of fibers.

15. Organically cross-linked silicic acid (hetero)polycondensate according to claim 13 in the form of bulk materials, composites, cements, adhesives, casting compounds, coating materials, adhesion promoters, fillers, fibers, and priming materials for fillers of fibers.

16. Method for producing a compound of formula (1) or a silicic acid (hetero)polycondensate comprising structures of formula (1) according to claim 1, comprising the steps: providing a silane or a silicic acid (hetero)polycondensate with the structure of formula (0), ##STR00015## wherein the residues and substituents R.sup.1, R.sup.2, R.sup.3, m, n and o have the same meaning as in formula (1) and reacting said silane or silicic acid (hetero)polycondensate with a compound of formula (II)
X(Ar).sub.b(II) wherein the groups, residues and indices Ar and b have the meanings specified for formula (1) and X is selected from HS, HNR.sup.4, HP(O)R.sup.4.sub.cZ.sub.d, with ZOR.sup.4 and R.sup.4 has the meaning specified for formula (1), c=0 or 1, d=0 or 1 and (c+d)=1, HN and HP(O).

17. Method according to claim 16, where the molar ratio of the R.sup.1 groups in the silane or of the structure (0) to compound (II) is between 5:1 and 1:1.

18. Method for producing a compound of formula (2) or a silicic acid (hetero)polycondensate comprising structures of formula (2) according to claim 1, comprising the steps: providing a silane or a silicic acid (hetero)polycondensate with the structure of formula (1), ##STR00016## wherein the groups, residues and indices have the same meaning as specified for structure (1), and reacting said silane or silicic acid (hetero)polycondensate with a compound of formula (III)
Q-W(R.sup.1).sub.b(III) wherein Q is selected from an isocyanate group, an epoxy group and, with the proviso that R.sup.2 in formula (1) is an OH-Group, from a carboxylic acid group COOH which can be present in activated form and, with the proviso that R.sup.2 is a carboxylic acid group or a salt or an ester thereof, from an OH-Group, W is a substituted or unsubstituted hydrocarbon residue, the chain of which can be interrupted by S, O, NH, NR.sup.4, C(O)O, NHC(O), C(O)NH, NHC(O)O, C(O)NHC(O), NHC(O)NH, S(O), C(S)O, C(S)NH, NHC(S), NHC(S)O, R.sup.1 is a straight chain or branched, organically polymerizable group, which carries at least one CC double bond, and b is 1, 2, 3, or an integer greater than 3, where the compound of formula (III) is employed in a stoichiometric or sub- or over-stoichiometric amount relative to the molar amount of R.sup.2.

19. Method for producing a compound having formula (3) or a silicic (hetero)polycondensate comprising structures of formula (3) according to claim 1, comprising the steps: providing a silane or a silicic acid (hetero)polycondensates with the structure of formula (1), ##STR00017## wherein the groups, residues and indices have the same meaning as specified for structure (1), and reacting said silane or silicic acid (hetero)polycondensate with a compound of formula (IV)
Q-W[-Q].sub.f(IV) wherein Q is selected from an isocyanate group, an epoxy group and, with the proviso that R.sup.2 in formula (1) is an OH group, from a carboxylic acid group COOH or an activated carbonyl compound derived therefrom and, with the proviso that R.sup.2 is a carboxylic acid group, from an OH group, or wherein two Q residues together are part of a cyclic, intramolecular anhydride of a dicarboxylic acid (C(O)O(O)C), W is either a substituted or unsubstituted hydrocarbon residue, the chain of which can be interrupted by S, O, NH, NR.sup.4, C(O)O, NHC(O), C(O)NH, NHC(O)O, C(O)NHC(O), NHC(O)NH, S(O), C(S)O, C(S)NH, NHC(S), and/or NHC(S)O or, with the proviso that each Q is an activated carboxylic acid group and f is equal to 1, represents a single bond, where in the case that Q is part of a cyclic intramolecular anhydride of a dicarboxylic acid, W is bonded via two carbon atoms with the C(O)O(O)C group, and f is 1, 2, 3, 4, 5 or 6 where the compound of formula (IV) is employed in such a stoichiometric ratio that the number of R.sup.2 residues and the number of the Q groups are present in a ratio of 1:1, or an excess of Q groups is present.

20. Method for producing a compound mixture or silicic acid (hetero)polycondensate according to claim 6, wherein variant (i) comprises the steps: providing a silane or a silicic acid (hetero)polycondensate with the structure of formula (1), ##STR00018## wherein the groups, residues and indices have the same meaning as specified for structure (1), and reacting said silane or silicic acid (hetero)polycondensate with a compound of formula (III)
Q-W(R.sup.1).sub.b(III) wherein Q is selected from an isocyanate group, an epoxy group and, with the proviso that R.sup.2 in formula (1) is an OH group, from a carboxylic acid group COOH which can be present in activated form and, with the proviso that R.sup.2 is a carboxylic acid group or a salt or an ester thereof, from an OH group, W is a substituted or unsubstituted hydrocarbon residue, the chain of which can be interrupted S, O, NH, NR.sup.4, C(O)O, NHC(O), C(O)NH, NHC(O)O, C(O)NHC(O), NHC(O)NH, S(O), C(S)O, C(S)NH, NHC(S), NHC(S)O, R.sup.1 represents a straight chain or branched, organically polymerizable group, which carries at least one CC double bond, and b is 1, 2, 3, or an integer greater than 3, where the compound of formula (III) is used in a substoichiometric amount relative to the molar amount of R.sup.2.

21. Method for producing a compound mixture or silicic acid (hetero)polycondensate according to claim 6, wherein variant (ii) comprises the steps: providing a silane or a silicic acid (hetero)polycondensate with the structure of formula (1), ##STR00019## wherein the groups, residues and indices have the same meaning as specified for structure (1), and reacting said silane or silicic acid (hetero)polycondensate with a compound of formula (IV)
Q-W[-Q].sub.f(IV) wherein Q is selected from an isocyanate group, an epoxy group and, with the proviso that R.sup.2 in formula (1) is an OH group, from a carboxylic acid group COOH or an activated carbonyl compound derived therefrom and, with the proviso that R.sup.2 is a carboxylic acid group, from an OH group, or wherein two residues Q together are part of a cyclic, intramolecular anhydride of a dicarboxylic acid (C(O)O(O)C), W is either a substituted or unsubstituted hydrocarbon residue, the chain of which can be interrupted by S, O, NH, NR.sup.4, C(O)O, NHC(O), C(O)NH, NHC(O)O, C(O)NHC(O), NHC(O)NH, S(O), C(S)O, C(S)NH, NHC(S), and/or NHC(S)O or, with the proviso that each Q is an activated carboxylic acid group and f is equal to 1, represents a single bond, where in the case that Q is part of a cyclic intramolecular anhydride of a dicarboxylic acid, W is bonded via two carbon atoms with the C(O)O(O)C group, and f is 1, 2, 3, 4, 5 or 6 where the compound of formula (IV) in employed in such a stoichiometric ratio that the number of R.sup.2 residues are greater than the number of Q groups.

22. Method for producing a compound mixture or silicic acid (hetero)polycondensate according to claim 6, wherein variant (iii) comprises the steps: providing a silane or a silicic acid (hetero)polycondensate with the structure of formula (1), ##STR00020## wherein the groups, residues and indices have the same meaning as specified for structure (1), reacting said compound mixture or silicic acid (hetero)polycondensate with a compound of formula (III)
Q-W(R.sup.1).sub.b(III) wherein Q is selected from an isocyanate group, an epoxy group and, with the proviso that R.sup.2 in formula (1) is an OH group, from a carboxylic acid group COOH which can be present in activated form and, with the proviso that R.sup.2 is a carboxylic acid group or a salt or an ester thereof, from an OH group, W is a substituted or unsubstituted hydrocarbon residue, the chain of which can be interrupted by S, O, NH, NR.sup.4, C(O)O, NHC(O), C(O)NH, NHC(O)O, C(O)NHC(O), NHC(O)NH, S(O), C(S)O, C(S)NH, NHC(S), NHC(S)O, R.sup.1 is a straight chain or branched, organically polymerizable group, which carries at least one CC double bond, and b is 1, 2, 3, or an integer greater than 3, in a molar amount of , and reacting said compound mixture or silicic acid (hetero)polycondensate with a compound of formula (IV)
Q-W[-Q].sub.f-(IV) wherein Q is selected from an isocyanate group, an epoxy group and, with the proviso that R.sup.2 in formula (1) is an OH group, from a carboxylic acid group COOH or an activated carbonyl compound derived therefrom and, with the proviso that R.sup.2 is a carboxylic acid group, from an OH group, or wherein two residues Q together are part of a cyclic, intramolecular anhydride of a dicarboxylic acid (C(O)O(O)C), W is either a substituted or unsubstituted hydrocarbon residue, the chain of which can be interrupted by S, O, NH, NR.sup.4, C(O)O, NHC(O), C(O)NH, NHC(O)O, C(O)NHC(O), NHC(O)NH, S(O), C(S)O, C(S)NH, NHC(S), and/or NHC(S)O, or, with the proviso that each Q is an activated carboxylic acid group and f is equal to 1, represents a single bond, where in the case that Q is part of a cyclic intramolecular anhydride of a dicarboxylic acid, W is bonded via two carbon atoms to the C(O)O(O)C group, and f is 1, 2, 3, 4, 5 or 6, in a molar amount /(f+1), relative to the index fin formula (IV), where the molar amounts are selected such the condition +/(f+1)<n is met, where the index n denotes the molar amount of groups R.sup.2 in the amount of compounds or silicic acid (hetero)polycondensate of structure (1) used.

Description

EXEMPLARY EMBODIMENTS

Example Ia. Synthesis of Base Resin System 1 with a Coupling Group R2 (OH) (Production According to DE 4416857)

(1) To 125.0 g (0.503 moles) of 3-glycidyloxypropylmethyldimethoxysilane (MW=236) triphenylphosphine as catalyst, BHT as stabilizer and then 47.35 g (0.550 moles) methacrylic acid are added dropwise in a dry atmosphere and stirred at 80 C. (approx. 24 h). The reaction can be followed by the decrease of the carboxylic acid concentration by means of acid titration and by the epoxide conversion by means of Raman spectroscopy/epoxide titration. The band characteristic of the epoxy group of epoxy silane appears in the Raman spectrum at 1256 cm.sup.1. After addition of acetic acid ester (1000 mL/mole silane) and H.sub.2O for hydrolysis with HCl as a catalyst, the reaction is stirred at 30 C. After approx. several days of stirring, the work-up is performed by repeated shaking out with aqueous NaOH and water and filtration through hydrophobized filters. The reaction is first spun off and then drawn off under an oil pump vacuum. The result is a liquid resin without use of reactive diluters (monomers) with a very low viscosity of approx. 3-5 Pa.Math.s at 25 C. and 0.00 mmoles CO.sub.2H/g (no free carboxyl groups) and a refractive index n.sub.D of approx. 1.477.

Example Ib. Synthesis of Base Resin System 2 without a Coupling Group R2 (Preparation According to DE 4011044)

(2) To 178 g (0.60 moles) of trimethylolpropane triacrylate (TMPTA), dissolved in acetic acid ester (1 L/mole TMPTA), 90.2 g (0.50 moles) of mercaptopropylmethyldimethoxysilane and ethanolic KOH with 5.0 mmoles KOH are added dropwise under argon with stirring (with cooling so that the temperature remains below 30 C.). The reaction mixture is further stirred for several minutes at room temperature. The completion of the reaction (thiol addition) can be monitored by means of the iodine-mercaptane test. After addition of H.sub.2O for hydrolysis/condensation with HCl as catalyst, the reaction is stirred at room temperature. Work-up is performed after approx. several days of stirring by repeated shaking out with water and filtering through hydrophobized filters. The reaction is first spun off and then drawn off under an oil pump vacuum. A liquid resin results.

Example IIa. Synthesis of the Example Series 1-1. Reaction Stage with Coupling Group R2 (OH)

(3) Basic Reaction Principle:

(4) ##STR00008##

Example IIa (1=0.2)

(5) To 26.8 g (0.10 moles) of base resin system 1, 2.20 g (0.020 moles) of thiophenol is added dropwise with stirring. The reaction can be followed e.g. by means of NMR. A liquid resin results with a viscosity of approx. 5.8-6.0 Pa.Math.s at 25 C. and a refractive index n.sub.D of approx. 1.493. Additional work-up is not required.

Example IIa-2 (1=0.4)

(6) To 39.7 g (0.15 moles) of base resin system 1, 6.61 g (0.079 moles) of thiophenol is added dropwise with stirring. A liquid resin results with a viscosity of approx. 7.0-7.2 Pa.Math.s at 25 C. and a refractive index n.sub.D of approx. 1.506. Additional work-up is not required.

Example IIa-3 (1=0.45)

(7) To 119.7 g (0.45 moles) of base resin system 1, 22.3 g (0.203 moles) of thiophenol is added dropwise with stirring. The reaction can be followed e.g. by means of NMR. A liquid resin results with a viscosity of approx. 7 Pa.Math.s at 25 C. and a refractive index n.sub.D of approx. 1.508. Additional work-up is not required.

(8) It is to be noted that the refractive index has increased only slightly (by 0.002) as compared to the product of Example IIa-2 due to the slightly increased thiophenol amount. It can thus be very finely adjusted.

(9) It is apparent from the comparison of the Examples Ia (comparator; starting material) 1a and 1b that the refractive index can be finely adjusted via the thiophenol amount: It can be seen that when 20 mole-% thiophenol is used as compound (II), a slight increase occurs as compared to the base resin system 1, with continues to increase when the molar amount of compound (II) is doubled.

(10) A liquid resin is formed in all three examples. Its viscosity increases only slightly from Example IIa-1 to IIa-3.

Example IIb. Synthesis of the Example Series 2-1. Reaction Stage with Coupling Group R2 (OH)

(11) Basic Reaction Principle:

(12) ##STR00009##

(13) The following components are used for 1=0.4: To 2.65 g (0.01 moles) of base resin system 1, 0.50 g (0.0044 moles) of methylbenzenethiol is added dropwise with stirring. The reaction can be followed e.g. by means of NMR. A liquid resin results at 25 C. and a refractive index n.sub.D of approx. 1.506. Additional work-up is usually not required.

Example IIc. Synthesis of the Example Series 5-1. Reaction Stage (with Coupling Group R2 (OH))

(14) Basic Reaction Principle:

(15) ##STR00010##

Example IIc (1=0.2)

(16) To 16.0 g (0.0615 moles) of base resin system 1, 2.48 g (0.0123 moles) of diphenylphosphine oxide and 0.2 mL of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) are added as a catalyst while stirring. The resulting reaction mixture is stirred at 50 C. until complete addition. The reaction can be followed e.g. by means of NMR. Following usual work-up e.g. in acetic ester (shaking out with water, filtration through hydrophobized filters, spinning off and then drawing off under an oil pump vacuum) a liquid resin results with a viscosity of approx. 37 Pa.Math.s at 25 C. and a refractive index n.sub.D1.500. The refractive index of the product of this Example is increased as compared to the refractive index of the Example IIa-1 (n.sub.D1.493, reaction of base resin system 1 with 0.2 molar amounts of HS-Ph; see Example series 1) with likewise 0.2 mole amounts of the adduct HP(O)(Ph).sub.2, i.e. the refractive index can be adjusted on a higher level. This is due to the presence of two phenyl groups per added molecule. The coupling group R.sub.2OH is not attacked during this reaction and can therefore be used for further addition of CC-containing compounds (e.g. according to Example IIIa-1; see Example series 4).

Example IId. Synthesis of the Example Series 3-1. Reaction Stage (without Coupling Group R2)

(17) Basic Reaction Principle:

(18) ##STR00011##

(19) The base resin system 2 (product of the Example Ib) was reacted with different amounts of thiophenol, where, however, care was taken to ensure that the molar amount (1) of thiophenol was below that of the silicon residues.

Example IIIa. Synthesis of the Example Series 4-2. Reaction Stage (with Coupling Group R2 (OH) and YNCO))

(20) Basic Reaction Principle:

(21) ##STR00012##

Example IIIa-1 (=0.8)

(22) To 15.4 g product from Example IIa-2 (0.05 moles) and 0.043 g BHT (2,6-di-tert-butyl-4-methyl phenol), 6.21 g (0.04 moles) of methacrylic acid-isocyanatoethylester (0.8 moles per mole of silicon-bonded R.sup.3 residue) are added dropwise in a dry atmosphere at 30 C. and further stirred at 30 C. The reaction can be followed e.g. by the decrease of the OCN band by means of the IR spectrum. The band characteristic of the OCN group appears in the IR spectrum at 2272 cm.sup.1. A liquid resin results with a viscosity of approx. 36 Pa.Math.s at 25 C. and a refractive index n.sub.D of approx. 1.502. Further work-up is not required.

Example IIIa-2 (=0.8)

(23) To 82.1 g from Example IIa-3 (0.26 moles) and 0.23 g BHT, 32.3 g (0.208 moles) of methacrylic acid isocyanatoethylester (0.8 moles per mole of silicon-bonded R.sup.3 residue) are added dropwise in a dry atmosphere at 30 C. with stirring and further stirred at 30 C. The reaction can be followed e.g. via the decrease of the OCN band by means of the IR spectrum. The band characteristic of the OCN group appears in the IR spectrum at 2272 cm.sup.1. A liquid resin results with a viscosity of approx. 37.6 Pa.Math.s at 25 C. and a refractive index n.sub.D of approx. 1.5044.

(24) Of note is that the refractive index is slightly increased (by 0.0024) as compared to the product of Example 4a due to the slightly increased amount of thiophenol.

(25) B. Preparation of Composite

(26) B1. Inventive Composite on the Basis of the Resin from Example IIIa-1

(27) Dental glass from the company Schott with the designation GM27884 (n.sub.D=1.53) and the specification UF0.7 (primary particle size of 0.7 m) is first incorporated into the resin of Example IIIa-1 by means of a three roll mill. Subsequently, dental glass with the specification K6 (primary particle size of 3 m) is incorporated using a planetary mixer. The glasses were added in a weight ratio of 1:2 (glass of specification UF0.7 to glass of specification K6). The total amount of glass in the composite was 70 wt.-%.

(28) B2. Inventive Composite on the Basis of the Resin from Example IIIa-1

(29) Example B1 was repeated with the difference that dental glass from the company Schott with the designation GM32087 (n.sub.D=1.52) and the specification UF0.4 (primary particle size of 0.4 m) was used and dental glass with the specification K6 (primary particle size of 3 m).

(30) B3. Comparative Composite on the Basis of Base Resin System 1

(31) Example B2 was repeated with the difference that instead of the resin of Example IIIa-1, the base resin system 1 served as composite matrix.

(32) C. Mechanical and Optical Data after Curing

(33) Polymerization/Curing of Different Resin Systems and Composites as Compared to the Underlying Base Resin

(34) The resins from the example series or the base resin system 1 and the composite resulting therefrom were each placed into a rod form (2225 mm.sup.3) together with 1% Lucirin TPO. The (meth)acrylate groups were converted by photo-induced radical polymerization, causing the resin to cure. By means of 3-point bending test on the universal testing machine Z100 of Zwick GmbH & Co. KG, the module of elasticity, the fracture strength and the deflection up to fracture of the resultant rods is determined after 1.5 days of storage at 40 C. Following the corresponding production of plate-shaped test bodies, the refractive index is determined by means of a refractometer. The shrinkage values are obtained by means of a buoyancy method in the context of the photo-induced radical polymerization (15 min/1 day after irradiation). The composites with 1% Lucirin TPO are placed in a mold (h=2 mm; d=18 mm), and cured in the context of photo-induced radical polymerization. The translucency is determined by means of a spectrophotometer Color i7 from x-rite.

(35) TABLE-US-00001 TABLE 1 Fracture Elastic Refractive Shrinkage resistance modulus Deflection index [Vol.-%] Resin system [MPa] [GPa] [mm] n.sub.D 15 min/1 day Base resin- 89 1.94 3.2 1.504 5.2/5.8 system 1 (comparator) 1. Reaction stage (with coupling group R.sub.2 (OH)) IIa-1 71 1.43 3.3 1.519 n.d. IIa-2 No realistic values, since 1.525 4.0/4.1 very high deflection IIc-1 94 2.22 2.8 1.519 2. Reaction stage (with coupling group R.sub.2 (OH) and Y = NCO)) IIIa-1 110-116 2.36-2.42 2.54-2.71 1.524 4.7/5.7 (For multiple measurements, the values shown in the table are mean values unless a range is specified)

(36) When the compound of formula (II) is added in the 1st reaction stage not only the expected decrease in the elastic modulus and a significant reduction in shrinkage is observed in addition to the refractive index increase, but surprisingly a strongly flexibilizing effect on the cured material is also found (especially with a high proportion of (II)).

(37) In contrast, the strength and elastic modulus (despite the reduced number of double bonds resulting from addition to some of the existing double bonds) during reaction IIc-1 are even slightly higher than those of the underlying base resin system 1.

(38) The refractive index is significantly increased in the 1st reaction stage in all cases.

(39) The cured materials of the 2nd reaction stage (addition of a compound of formula (III))even with a high proportion of previously added compounds (II) (with a resulting very low organic networking potential and the resulting flexibilzing effect and reduced fracture strength)surprisingly also yield a hard material with high strength and increased refractive index with significantly improved mechanical data and reduced shrinkage, as compared to the underlying base resin system (here base resin system 1), while the refractive index is significantly increased.

(40) TABLE-US-00002 TABLE 2 Fillers Composite Type/ratio of Fracture Elastic on the Amount fillers to each strength modulus Deflection Translucency basis of (wt.-%] other [MPa] [GPa] [mm] [%] B3 70 GM27884/ 131 6.95 0.73 38 UF0.7:K6 = 1:2 After 2nd reaction stage (with coupling group R.sub.2 (OH) and Y = NCO)) B1 70 GM27884/ 151 7.92 0.71 61 UF0.7:K6 = 1:2 B2 70 GM32087/ 147 8.19 0.67 58 UF0.4:K6 = 1:2

(41) The refractive index of the cured resin system IIIa-1 is exactly between those of the two fillers used. Both composites (B1. and B2.) on the basis of the modified resin system IIIa-1 yield, with the same filler amount/type/ratio, a significant increase in translucency with simultaneous increase in strength and elastic modulus as compared to the composite on the basis of the unmodified base resin system-1 (comparator Example B3.). Composites are thereby made accessible that have high translucency and strength at the same time.