Amine-catalyzed thiol-curing of epoxy resins

Abstract

A composition containing an epoxide compound with two or more epoxide groups, a thiol ester with two or more ester groups and two or more thiol groups and/or a thiol ether with two or more thiol groups, and 0.005-2 wt. %, based on the total weight of the composition, of a tertiary amine which has a 5- or 6-membered aliphatic nitrogen heterocycle, said composition containing less than 1 wt. % of a primary amine. The composition can be used as an embedding medium for microscopy and as an adhesive and to an optical element which comprises the composition.

Claims

1. A composition comprising: (A) an epoxy compound with two or more epoxy groups, (B) at least one oligomeric thiourethane, and (C) a tertiary amine comprising a 5- or 6-membered aliphatic nitrogen heterocycle in an amount of 0.005-2 wt.-%, based on the total weight of the composition, wherein the composition contains less than 1 wt.-%, based on the total weight of the composition, of a primary amine; and wherein an average number of monomers comprising the oligomeric thiourethane is between 3 and 100.

2. The composition of claim 1, wherein the tertiary amine is selected from the group consisting of 1-(2-hydroxyethyl)pyrrolidine, 1-(2-hydroxyethyl)pyrrolidone, 1-(2-hydroxyethyl)piperidine, 1-ethylpiperazine, 1-(2-hydroxyethyl)piperazine, 1,4-bis-(2-hydroxyethyl)piperazine, 1-methylimidazole, 4-(2-hydroxyethyl)morpholine, 1,4-diazabicyclo[2.2.2]octane (DABCO), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

3. The composition of claim 1, wherein the oligomeric thiourethane comprises at least 4 free thiol groups.

4. The composition of claim 1, wherein an average number of monomers comprising the oligomeric thiourethane is between 5 and 25.

5. The composition of claim 1, comprising two or more oligomeric thiourethanes.

6. The composition of claim 4, wherein an average number of the monomers contained in the oligomeric thiourethane is between 5-25 and a proportion of the oligomeric thiourethane or of the oligomeric thiourethanes, based on the total weight of the composition, is 10-50 wt.-%.

7. The composition of claim 1, wherein the at least one oligomeric thiourethane is made from pentaerythritol tetra(3-mercaptopropionate) (PTMP) with xylylene diisocyanate (XDI), pentaerythritol tetra(3-mercaptopropionate) with norbornyl diisocyanate (NBDI), or pentaerythritol tetra(3-mercaptopropionate) with isophorone diisocyanate (IPDI).

8. The composition of claim 1, wherein (A) the epoxy compound with two or more epoxy groups comprises bisphenol A diglycidyl ether and/or bisphenol F diglycidyl ether, (B) the at least one oligomeric thiourethane is present in an amount of 10-50 wt.-% is obtained from pentaerythritol tetra(3-mercaptopropionate) (PTMP) and/or trimethylolpropane tri(3-mercaptopropionate) (TPMP) with xylylene diisocyanate (XDI), norbornyl diisocyanate (NBDI) and/or isophorone diisocyanate (IPDI), wherein each oligomeric thiourethane comprises two or more free thiol groups, and (C) the tertiary amine comprising the 5- or 6-membered aliphatic nitrogen heterocycle is selected from the group consisting of 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,4-diazabicyclo[2.2.2]octane (DABCO) in an amount of 0.005-0.3 wt.-%, based on the total weight of the composition, or 1-(2-hydroxyethyl)pyrrolidine, 1-(2-hydroxyethyl)pyrrolidone, 1-(2-hydroxyethyl)piperidine, 1-ethylpiperazine, 1-(2-hydroxyethyl)piperazine, 1,4-bis-(2-hydroxyethyl)piperazine, 1-methylimidazole and 4-(2-hydroxyethyl)morpholine, in an amount of 0.3-2 wt.-%, based on the total weight of the composition.

9. The composition of claim 1, wherein the composition further comprises (D) a photolatent base in an amount of 0.5-2 wt.-% selected from the group consisting of substituted 5-(carbonylarylmethyl)-1,5-diazabicyclo[4.3.0]nonane and substituted 8-(carbonylarylmethyl)-1,8-diazabicyclo[5.4.0]undecane, and (E) a photoinitiator.

10. An adhesive comprising the composition according to claim 1.

11. A cement comprising the adhesive according to claim 10.

12. An embedding medium for microscopy comprising the composition according to claim 1.

13. An optical element for a display device that can be fitted on the head of a user and generates an image, the optical element comprising a front side and a rear side, a coupling-in section and a coupling-out section spaced apart from the coupling-in section, and a light guiding channel which is suitable for guiding light bundles of pixels of the generated image, which are coupled into the optical element via the coupling-in section of the optical element, in the optical element to the coupling-out section, by which they are coupled out of the optical element, wherein the optical element comprises an inner and an outer shell joined to each other with a composition according to claim 1.

14. A display device having a holder that can be fitted on the head of a user, an image-generating module secured to the holder, which generates an image, and an imaging optical system secured to the holder, which comprises an optical element according to claim 13 and which, when the holder is fitted on the user's head, images the generated image such that the user can perceive it as a virtual image.

15. The composition of claim 4, wherein the oligomeric thiourethane is obtained by reacting at least one thiol ester that comprises two or more ester groups and two or more thiol groups and/or at least one thioether that comprises two or more thiol groups, with at least one di- or polyisocyanate, wherein the oligomeric thiourethane comprises two or more free thiol groups.

16. The composition of claim 5, wherein the oligomeric thiourethanes is obtained by reacting at least one thiol ester that comprises two or more ester groups and two or more thiol groups and/or a thioether that comprises two or more thiol groups, with at least one di- or polyisocyanate, wherein each oligomeric thiourethane comprises two or more free thiol groups.

17. The composition of claim 5, wherein an average number of the monomers contained in the oligomeric thiourethane is between 5-25 and a proportion of the oligomeric thiourethane or of the oligomeric thiourethanes, based on the total weight of the composition, is 10-50 wt.-%.

18. The composition of claim 1, wherein the at least one oligomeric thiourethane is a thioether comprising 2,3-bis(2-mercaptoethylsulfanyl)propane-1-thiol.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained in even more detail below by way of example with reference to the attached drawings, which also disclose features essential to the invention. For greater clarity, a representation which is accurate in terms of scale and proportion is dispensed with at least partially in the figures and there is no shading. There are shown in:

(2) FIG. 1 an embodiment of the display device according to the invention;

(3) FIG. 2 an enlarged partial sectional view of the optical element 1 according to the invention including a schematic representation of the image-generating module;

(4) FIGS. 3-7 partial sectional views to explain the production of the optical element according to the invention, and

(5) FIG. 8 a partial sectional view to explain an alternative way of producing the optical element according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

(6) In the embodiment shown in FIG. 1, the display device 1 according to the invention comprises a holder 2 that can be fitted on the head of a user, which can be formed e.g. in the manner of a conventional spectacles frame, as well as a first and a second spectacle lens 3, 4, which are secured to the holder 2. The holder 2 with the spectacle lenses 3, 4 can be formed e.g. as sports glasses, sunglasses and/or glasses for correcting defective vision, wherein a virtual image can be reflected into the user's field of view via the first spectacle lens 3, as is described below.

(7) For this purpose, the display device 1 comprises an image-generating module 5, which can be arranged in the area of the right-hand temple stem of the holder 2, as is represented schematically in FIG. 1. The image-generating module 5 can comprise a two-dimensional image-generating element 6 (FIG. 2), such as e.g. an OLED, an LCD or an LCoS chip or a tilting mirror matrix, with a plurality of pixels arranged e.g. in columns and rows.

(8) The spectacle lenses 3 and 4, and in particular the first spectacle lens 3, are only described together with the display device 1 according to the invention by way of example. The spectacle lenses 3, 4, or at least the first spectacle lens 3, are in each case formed separately as a spectacle lens 3, 4 according to the invention or as an optical element according to the invention. The optical element according to the invention can also be used in another context than with the display device 1 described here. Therefore, the optical element, when it is formed as a spectacle lens, can, naturally, also be formed as second spectacle lens 4.

(9) As can best be seen from the enlarged schematic partial sectional view in FIG. 2, the display device 1 comprises an imaging optical system 7 which contains an optical element 8 arranged between the image-generating element 6, or the imaging system 6, and the first spectacle lens 3. In addition, the first spectacle lens 3 itself also serves as part of the imaging optical system 7.

(10) A light bundle 9 can emerge from each pixel of the imaging system 6. The desired image can be generated by correspondingly actuating the pixels of the imaging system 6 by means of a control unit 10, which can be part of the image-generating module 5. In FIG. 2, the beam path of a light beam is drawn in to represent the light bundles 9, with the result that the light beam 9 is also discussed hereafter.

(11) The light beam 9 emerging from the imaging system 6 runs through the optical element 8 and enters the first spectacle lens 3 via a coupling-in section 11 (here the end face of the first spectacle lens 3), and is guided in this along a light guiding channel 12 to a coupling-out section 13. The coupling-out section 13 comprises several reflective deflecting surfaces 14 (which can also be referred to as reflective facets) arranged next to each other on which a reflection of the light beams 9 takes place in the direction of a rear side 15 of the first spectacle lens 3, with the result that the light beams 9 exit the first spectacle lens 3 via the rear side 15.

(12) Thus, when a user is wearing the display device 1 according to the invention on his head as intended, he can perceive the image generated by means of the imaging system 6 as a virtual image when he looks at the coupling-out section 13. In the embodiment described here, the user must look towards the right by approx. 40 relative to the direction of view G of a forward view. In FIG. 2, the centre of rotation 16 of the user's eye, as well as the eyebox 17 or the exit pupil 17 of the imaging optical system 7 is drawn in for clarification. The eyebox 17 is the area which is provided by the display device 1 and in which the user's eye can move and he can still see the generated image as a virtual image.

(13) Although in the described embodiment the coupling-in is carried out via the end face of the first spectacle lens 3 and thus the coupling-in section 11 is formed on the end face of the first spectacle lens 3, it is also possible to carry out a coupling-in via the rear side 15 of the first spectacle lens.

(14) As is shown in the schematic representation in FIG. 2, both the rear side 15 and the front side 18 of the first spectacle lens 3 are formed curved.

(15) Furthermore, as can be learned in particular from the representations in FIG. 2, the first spectacle lens 3 is formed with two shells and comprises an outer shell 19 with a first and second side 20 and 21 and an inner shell 22 with a first and second side 23 and 24.

(16) The first side 20 of the outer shell 19 forms the front side 18 of the first spectacle lens 3 and the first side 23 of the inner shell 22 forms the rear side 15 of the first spectacle lens 3. The second side 21 of the outer shell 18 and the second side 24 of the inner shell 22, which face each other, have complementary curvatures and are connected flat to each other via an adhesive layer 31. To form the adhesive layer 31, the composition according to the invention can be used as adhesive for bonding the two shells 19, 22.

(17) The light guiding channel 12 is formed such that the desired guiding of the light beams 9 takes place from the coupling-in section 11 to the coupling-out section 13. This can take place, e.g., through total internal reflection on the front side 18 (=first side 20 of the outer shell 19) and the rear side 15 (=first side 23 of the inner shell 22). Of course, it is also possible for a reflective coating, which brings about the desired reflection of the light beams 9, to be formed on the front side 18 and/or on the rear side 15 in the area of the light guiding channel 12. The reflectivity of the reflective coating can e.g. be as high as possible (approx 100%) or lower. The reflective coating can thus be formed as a mirror layer or as a partially reflective layer.

(18) In the embodiment described here, the two sides 20, 21 of the outer shell 19 are spherically curved and the first side 20 of the outer shell 19 has a radius of curvature of 94 mm and the second side 21 of the outer shell 19 has a radius of curvature of 92 mm. The thickness of the outer shell is thus 2 mm. However, the outer shell 19 can also be formed with a smaller thickness. The thickness of the outer shell 19 can thus be in the range of from 0.15 mm to less than 2 mm. In particular, the outer shell 19 can be formed as a dimensionally stable film. Here, by dimensionally stable is meant in particular that the film at least withstands the force of gravity and thus retains its shape if no other forces are acting on it.

(19) The second side 24 of the inner shell 22 is spherically curved and has a radius of curvature which corresponds to the radius of the second side 21 of the outer shell 19. Here, this is therefore a radius of 92 mm. The first side 23 of the inner shell 22 is spherically curved and has the radius of curvature required to correct the user's defective vision (e.g. 150 mm when PMMA is used as material for the inner shell 22). Of course, the first side 23 of the inner shell can also be aspherically curved. The material of the outer shell 19 is preferably the same as the material of the inner shell 22. The thickness of the inner shell 22 depends substantially on the difference between the radius of the second side 24 of the inner shell 22 and the first side 23 of the inner shell 22 and, in the example described here, is approx. 3 mm.

(20) As already mentioned, the materials of the inner and outer shell 22 and 19 are preferably the same, with the result that they have an identical refractive index. The inner and outer shell 22 and 19 are preferably bonded over the whole surface via the adhesive layer 31, with the result that a compact first spectacle lens 3 is provided.

(21) The first spectacle lens 3 of the embodiment described here provides a correction of +2 dioptres.

(22) The optical element according to the invention can be produced as follows:

(23) In a first step, a first semi-finished part 25 is produced in the injection mould from a thermoplastic polymer. As is shown in the enlarged partial sectional view from FIG. 3, the first semi-finished part 25 comprises the first side 23 and the second side 24. A microstructuring 26, which simulates the shape of the desired reflective facets 14, is formed on the second side 24.

(24) The first semi-finished part 25 is then coated with an optically active layer 27, which is represented with a dotted line, in the area of the microstructuring 26 (to simplify the representation, the layer 27 is not drawn in in FIG. 2). Known coating methods can be used for this, such as e.g. chemical vapour deposition (CVD) or physical vapour deposition (PVD). The optically active layer 27, which is represented with dots in FIG. 4, is chosen such that the described reflective facets 14 are provided.

(25) The indentations which are present because of the microstructuring 26, which extend from the second side 24 into the semi-finished part 25, are filled in in a following step such that a smooth continuous second side 24 results (FIG. 5). For filling the indentations, the same material 28 as the material for producing the semi-finished part 25 or an optical cement or optical adhesive 28 can be used. In particular, the composition according to the invention can be used.

(26) Then, the outer shell 19 is produced in injection moulding from a thermoplastic polymer as second semi-finished part 30 such that it comprises the first and second side 20, 21. Alternatively, the second semi-finished part 30 can be produced before the production of the first semi-finished part 25 or at the same time as the first semi-finished part 25. This second semi-finished part 28 is then bonded to the first semi-finished part 25 over the whole surface. For this, the second side 21 of the second semi-finished part 30 and/or the second side 24 of the first semi-finished part 25 can be coated with an optical adhesive or an optical cement in order to form an adhesive layer 31. In FIG. 6, the case is shown in which the second side 24 of the first semi-finished part 25 is coated with the adhesive layer 31. Then, the two semi-finished parts are brought into contact with each other at their surfaces 21 and 24 via the adhesive layer 31, which can also be referred to as adhesion layer, as is indicated by the arrows P1 in FIG. 6, and the adhesive layer 31 is cured in order thus to produce the optical element 3 according to the invention, as it is shown in FIG. 7. Thus, the optical element 3 according to the invention is present, which is built up in two shells, wherein the outer sides 23 and 20 of the two shells 19 and 22 form the rear side 15 and the front side 18 of the first spectacle lens 3.

(27) Different materials can be used as material for the two semi-finished parts 25 and 30. However, the same material is preferably used for both semi-finished parts 25 and 30. In particular, thermoplastic polymers and/or thermosetting polymers are used.

(28) As thermoplastic polymers e.g., PMMA (polymethyl methacrylate, e.g. Plexiglas), PA (polyamide, e.g. Trogamid CX), COP (cyclo olefin polymers, e.g. Zeonex), PC (polycarbonate, poly(bisphenol A carbonate), e.g. Makrolon), LSR (Liquid Silicone Rubber, e.g. Silopren, Elastosil), PSU (polysulfone, e.g. Ultrason), PES (polyethersulfone) and/or PAS (poly(arylene sulfone)) can be used. As thermosetting polymers e.g., ADC (allyl diglycol carbonate, e.g. CR-39), acrylates (e.g. Spectralite), PUR (polyurethanes, e.g. RAVolution), PU/PUR (polyureas, polyurethanes, e.g. Trivex), PTU (polythiourethanes, e.g. MR-8, MR-7) and/or polymers based on episulfide/polythiol (e.g. MR-174) can be used.

(29) In FIG. 8, in an enlarged sectional representation, the first semi-finished part 25 is shown with the microstructuring 26 and the optically active layer 27. Unlike in the previously described filling in of the microstructuring 26 in one step, in the variant according to FIG. 8 this is carried out in two steps. In this way, an undesired shrinkage which can occur on curing of the material of the filling layers 28.sub.1, 28.sub.2 (filling layer 28.sub.1 and then filling layer 28.sub.2) can be minimized. Of course, the filling in can also be carried out in more than two steps, e.g. in three, four, five or six steps.

(30) In the display device 1 according to the invention the virtual image is reflected into the user's field of view via the first spectacle lens 3. Of course, a reflection via the second spectacle lens 4 is also possible. Furthermore, the display device 1 can be formed such that items of information or virtual images can be reflected via both spectacle lenses 3, 4. The reflection can take place such that a three-dimensional image impression results. However, this is not absolutely necessary.

(31) The spectacle lenses 3, 4 can have a refractive power of zero or a refractive power different from zero (in particular for the correction of defective vision). As is shown in the figures, both the front side 11 and the rear side 12 of the spectacle lens 3 are formed curved. In particular, the front side 11 can be spherically curved. If the spectacle lens has a refractive power different from zero, in order to correct defective vision, as a rule the curvature of the rear side 15 is chosen appropriately, in order to achieve the corresponding correction. The rear side 15 can have a curvature which differs from the spherical shape.

(32) The holder 2 does not have to be formed as a spectacle-type holder. Any other type of holder with which the display device can be fitted or worn on the head of the user is also possible.

(33) In the described embodiment examples, the spectacle lens 3 is formed with two shells. However, it is also possible to produce the spectacle lens with more than two shells, e.g. at least three shells. In particular, the spectacle lens can be produced from two parts (which do not necessarily need to be shells) or from more than two parts. The shells or parts are then preferably bonded with the composition according to the invention.

(34) The Following Examples Explain the Invention.

(35) The compositions mentioned below were prepared by mixing the components in the stated sequence of the resin and by producing the hardener separately therefrom by mixing the components in the named sequence of the hardener and by subsequently mixing resin and hardener in the stated ratio. Where stated, the mixing of resin and hardener took place in dual cartridges, as are customary in adhesive technology, in which resin and hardener are mixed by pushing them through a mixing section in the form of a helix (static mixing tube), wherein the ratio x+y, for example 2+1, indicates the weight ratio of resin to hardener.

(36) With the adhesives described below, sufficiently long processing times of about 60-120 min. could be obtained accompanied by a complete full cure within about 4-6 hours (at room temperature) and excellent adhesion was achieved. With the described embedding media, excellent image qualities could be obtained on the microscopic examination of tissue sections.

(37) 1. Adhesives: Structural Adhesives, Setting Adhesives

EXAMPLE 1

(38) Resin: 100 parts by weight Araldite F 3 parts by weight Glymo 0.02 parts by weight Seripas Red Hardener: 100 parts by weight pre-polymer PTMP/XDI (100+10 parts by weight) 3 parts by weight 1-(2-hydroxyethyl)pyrrolidine as amine base Batch: 100 parts by weight resin+80 parts by weight hardener

EXAMPLE 2

(39) Resin: 75 parts by weight Araldite F 20 parts by weight colourless resin adhesive 52A (plasticized epoxy resin) 5 parts by weight glycerol tribenzoate 3 parts by weight Glymo 0.02 parts by weight Seripas Red Hardener: 40 parts by weight pre-polymer PTMP/XDI (100+10 parts by weight) 60 parts by weight PTMP 5 parts by weight 1-ethylpiperazine as amine base Suitable for application in 2+1 dual cartridges

EXAMPLE 3

(40) Resin: 50 parts by weight Araldite F 50 parts by weight Nanopox F 440 3 parts by weight glycerol tribenzoate 3 parts by weight Glymo 0.02 parts by weight Seripas Red Hardener: 100 parts by weight PTMP 0.35 parts by weight DABCO as amine base Suitable for application in 2+1 dual cartridges

EXAMPLE 4

(41) Resin: 100 parts by weight Araldite F 3 parts by weight Glymo 0.02 parts by weight Sudan Blue 50 parts by weight Silbond FW 12 EST (fused silica flour, silanized) Hardener: 100 parts by weight pre-polymer PTMP/XDI (100+10 parts by weight) 0.5 parts by weight DABCO as amine base Batch: 100 parts by weight resin+55 parts by weight hardener

EXAMPLE 5

(42) Resin: 100 parts by weight Epalloy 5000 3 parts by weight Glymo 0.02 parts by weight Sudan Blue Hardener: 100 parts by weight PTMP 0.5 parts by weight DABCO as amine base Suitable for application in 2+1 dual cartridges

EXAMPLE 6

(43) Resin: 30 parts by weight Rutapox 0158 30 parts by weight Rutapox 0162 40 parts by weight 1,4-butanediol diglycidyl ether 3 parts by weight Glymo 0.02 parts by weight Sudan Blue Hardener: 100 parts by weight pre-polymer PTMP/XDI (100+10 parts by weight) 0.1 parts by weight DBU as amine base Suitable for application in 1+1 dual cartridges

EXAMPLE 7

(44) Resin: 50 parts by weight Rutapox 0158 50 parts by weight Rutapox 0162 3 parts by weight Glymo 0.02 parts by weight Sudan Blue Hardener: 70 parts by weight pre-polymer PTMP/XDI (100+10 parts by weight) 30 parts by weight Thioplast G44 0.25 parts by weight DABCO as amine base Suitable for application in 1+1 dual cartridges

EXAMPLE 8

(45) Resin: 20 parts by weight Araldite F 60 parts by weight Nanopox F 440 20 parts by weight IPDX CL 16 0.02 parts by weight Sudan Blue Hardener: 100 parts by weight PTMP 4 parts by weight MTMO (3-mercaptopropyltrimethoxysilane) 0.3 parts by weight DABCO as amine base Suitable for application in 2+1 dual cartridges
2. Adhesives with Optical Properties: Cements, Embedding Media for Microscopy

EXAMPLE 9

(46) Resin: 60 parts by weight Rutapox 0158 40 parts by weight Rutapox 0162 2 parts by weight Glymo, distilled Hardener: 100 parts by weight PTMP 0.12 parts by weight DABCO as amine base Batch: 100 parts by weight resin+70 parts by weight hardener Refractive power (cured) at 20 C.: ne=1.596

EXAMPLE 10

(47) Resin: 35 parts by weight Rutapox 0158 25 parts by weight Rutapox 0162 40 parts by weight 1,4-butanediol diglycidyl ether, distilled 2 parts by weight Glymo, distilled Hardener: 100 parts by weight PTMP 0.25 parts by weight DABCO (amine base) Batch: 100 parts by weight resin+85 parts by weight hardener Refractive power (cured) at 20 C.: ne=1.571

EXAMPLE 11

(48) Resin: 40 parts by weight Epalloy 5000, distilled 60 parts by weight Erisys GE 22, distilled 3 parts by weight Glymo, distilled Hardener: 100 parts by weight pre-polymer TPMP/XDI (100+5.6 parts by weight) 4 parts by weight 1-(2-hydroxyethyl)piperazine, distilled as amine base Batch: 100 parts by weight resin+90 parts by weight hardener Refractive power (cured) at 20 C.: ne=1.540

EXAMPLE 12

(49) Resin: 60 parts by weight Rutapox 0158 40 parts by weight Rutapox 0162 2 parts by weight Glymo, distilled Hardener: 50 parts by weight PTMP 50 parts by weight TEMPIC 0.2 parts by weight DABCO as amine base Batch: 100 parts by weight resin+85 parts by weight hardener Refractive power (cured) at 20 C.: ne=1.592

EXAMPLE 13

(50) Resin: 62 parts by weight Rutapox 0158 38 parts by weight Rutapox 0162 2 parts by weight Glymo, distilled Hardener: 100 parts by weight MR7 B 0.12 parts by weight DABCO as amine base Batch: 100 parts by weight resin+50 parts by weight hardener Refractive power (cured) at 20 C.: ne=1.637
3. UV Activatable Adhesive Systems: The UV activation takes place by irradiating with a high-pressure mercury vapour lamp or with a UV LED preferably at 365 nm. Irradiation rate approx. 80-120 mW/cm.sup.2 for 30 to 120 seconds. During the UV activation there is a rapid colour change of the mixed adhesive from blue to yellow (colour indicator for the UV activation).

EXAMPLE 14

(51) Resin: 100 parts by weight Araldite F 3 parts by weight Glymo 5 parts by weight Darocur 1173 (radical initiator) 0.02 parts by weight Sudan Blue Hardener: 100 parts by weight pre-polymer PTMP/XDI (100+10 parts by weight) 5 parts by weight methoxycarbonylbenzyl DBN as photolatent amine base 2 parts by weight 1-ethylpiperazine as additional amine base Batch: 100 parts by weight resin+80 parts by weight hardener

EXAMPLE 15

(52) Resin: 40 parts by weight Araldite F 60 parts by weight Nanopox F 440 3 parts by weight Glymo 6 parts by weight Darocur 1173 (radical initiator) 0.02 parts by weight Sudan Blue Hardener: 80 parts by weight PTMP 20 parts by weight TEMPIC 5 parts by weight methoxycarbonylbenzyl DBN as photolatent amine base Suitable for application in 2+1 dual cartridges

EXAMPLE 16

(53) Resin: 30 parts by weight Epalloy 8330* 70 parts by weight Araldite F 8 parts by weight Darocur 1173 5 parts by weight Glymo 0.02 parts by weight Sudan Blue 35 parts by weight Silbond FW 12 EST 30 parts by weight Silbond FW 600 EST

(54) *epoxidized phenol novolac resin, manufacturer CVC Specialty Chemicals Hardener: 100 parts by weight pre-polymer PTMP/XDI (100+12 parts by weight) 5 parts by weight PL-DBN** 0.1 parts by weight DABCO (amine catalyst)

(55) ** PL-DBN=photolatent amine base DBN

(56) photoactivatable, suitable for 2+1 dual cartridges

(57) 4. Cement with High Adaptation of Refractive Power to Polycarbonate:

EXAMPLE 17

(58) Resin: 90 parts by weight Araldite F 10 parts by weight Epalloy 5000 3 parts by weight Glymo n.sub.e.sup.21=1.5649, D.sub.20=1.175 g/cm.sup.3 Hardener: 90 parts by weight pre-polymer PTMP/XDI (100+10 parts by weight) 10 parts by weight pre-polymer MR7 B/XDI (100+20 parts by weight) 0.1 parts by weight DABCO (amine catalyst) n.sub.e.sup.21=1.5568, D.sub.20=1.300 g/cm.sup.3 Batch: 100 parts by volume resin 60 parts by volume hardener (processing with mixing equipment) mixture n.sub.e.sup.21=1.5609 pot life (2 g) approx. 60 min. cured n.sub.e.sup.21=1.5912 polycarbonate (LQ 2647) n.sub.e.sup.21=1.5912 target wavelength is 546 nm (n.sub.e)
Measured Values of the Cured Mixture According to Example 16: n.sub.g (435.8 nm)=1.6078 n.sub.F.sup.(480.0 nm)=1.5996 n (508.5 nm)=1.5955 n.sub.e (546.1 nm)=1.5910, after a further 5 d/RT 1.5912 (thereafter refractive power stable) n (578.0 nm)=1.5880 n.sub.g (589.3 nm)=1.5870 n.sub.c (643.8 nm)=1.5826 (n.sub.F.sup.n.sub.c.sup.1)=0.0170 .sub.c=34.8
Comparison with Makrolon (Polycarbonate; LQ 2647), flat plate D=80 mm, d=2 mm n.sub.g (435.8 nm)=1.6123 n.sub.F.sup.(480.0 nm)=1.6017 n (508.5 nm)=1.5966 n.sub.e (546.1 nm)=1.5912 n (578.0 nm)=1.5875 n.sub.D (589.3 nm)=1.5864 n.sub.c (643.8 nm)=1.5819 (n.sub.F.sup.n.sub.c.sup.1)=0.0198 .sub.e=29.9

(59) The cements can additionally also contain additives, e.g. against yellowing through the action of daylight/sunlight in the form of so-called UV absorbers, e.g. Tinuvin P, Tinuvin 109, Tinuvin 900 or 2,4-dihydroxybenzophenone.

(60) Described above are just a few exemplary embodiments of the present invention. The principle according to the present invention is naturally subject to modifications within the scope of protection defined by the claims, regarding for example implementation details as well as fields of use. The present invention is not limited solely to the foregoing exemplary embodiment, but many variations are possible while remaining within an inventive concept defined by the claims.