Combination of homologous photochromic annulated naphthopyrans for easily realising aesthetic grey and brown colour tones in phototropic polymers

Abstract

The present invention relates to the combination of two specific homologous photochromic annulated naphthopyran isomers according to formulae (I) and (II) below, and to the incorporation thereof into polymers for corresponding phototropic products. These phototropic polymers are characterised by very stable and aesthetically pleasing colour tones in the darkened state. In addition, this makes it possible to realise phototropic products which darken intensely and lighten again very quickly.

Description

[0001] Combination of homologous photochromic annelated naphthopyrans for the simple realization of aesthetic grey and brown hues.

[0002] in phototropic polymers

[0003] The present invention relates to the combination of two special homologous photochromic annelated naphthopyran isomers according to formulas (I) and (II) below and their incorporation into polymers for corresponding phototropic products. These phototropic polymers are characterized by very stable and aesthetically pleasing darkening shades. Furthermore, deeply darkening and very quickly lightening phototropic products can be produced in this way.

[0004] Thiourethane polymers are by far the most widely used materials for plastic spectacle lenses with higher refractive indices of > 1.60. EP 4240797 describes the use of a specific combination of two different photochromic fused naphthopyran isomers, according to the formulas specified therein, particularly for incorporation into thiourethane polymers. The two naphthopyran isomers combined in EP 4240797 exhibit different tinting shades, which, in combination, complement each other to produce, for example, aesthetically pleasing gray or brown tones.

[0005] The present invention is based on the objective of providing new systems whose incorporation, particularly into thiourethane polymers, leads to phototropic polymers characterized by very stable and aesthetically pleasing darkening colors. Incorporation should also be possible, in particular, by mass dyeing.

[0006] This problem is solved by the items specified in the claims.

[0007] In particular, the novel combination of two homologous, photochromic annulated naphthopyrans is provided according to the following general formulas (I) and (II):

[0008]

[0009] where in formulas (I) and (II)

[0010] m is an integer between 0 and 1,

[0011] n is an integer between 0 and 1, and

[0012] p represents an integer between 0 and 50;

[0013] The residues Ri, R2 and R3 each independently represent a substituent, selected from hydrogen, bromine, chlorine, fluorine, a (Ci-Ce) alkyl residue, a (C3-C7) cycloalkyl residue, a (Ci-Cej) thioalkyl residue, a (Ci-Ce) alkoxy residue, a trifluoromethyl residue, a phenyl residue, a 4-methoxyphenyl residue, a phenoxy residue, a 4-methoxyphenoxy residue, a benzyl residue, a 4-methoxybenzyl residue, a benzyloxy residue, a 4-methoxybenzyloxy residue, a biphenyl residue, a biphenyloxy residue, a naphthyl residue, a naphthoxy residue, a di-(Ci-C6) alkylamino residue, a piperidinyl residue, a 3,5-Dimethylpiperidinyl residue, an indolinyl residue, a morpholinyl residue, a 2,6-dimethylmorpholinyl residue, a thiomorpholinyl residue, an azacycloheptyl residue, a phenylamino residue, a (Ci-C6)-alkylphenylamino residue, a diphenylamino residue, a (4-methyloxyphenyl)phenylamino residue, a bis(4-methoxyphenyl)amino residue,a (4-ethoxyphenyl)phenylamino residue, a bis(4-ethoxyphenyl)amino residue, a 10,10-dimethyl-9,10-dihydroacridine residue, a phenothiazinyl residue, a phenoxazinyl residue, a phenazinyl residue, a carbazolyl residue, a 1,2,3,4-tetrahydrocarba-zolyl residue or a 10,11-dihydro-dibenz[b,f]azepinyl residue;

[0014] or the residues Ri and R2 together represent the group -X-(CH2)qY-, wherein X and Y are independently selected from the groups -0-, -S-, -N(Ci— Ce)-alkyl, -NCeHs-, -CH2-, -C(CH3)2-, -C(C2HS)2- or -C(C6Hs)2- and q is an integer from 1 to 3; with the proviso that if this numerical value is 2 or 3, a benzene ring may also be fused to two adjacent CH2 groups; and with the further proviso that if X or Y represent -CH2-, they may also represent a fused benzene ring together with the respective adjacent CH2 group;

[0015] the residues R4 and Rs each independently represent a substituent, selected from a (Ci-Ce) alkyl residue, a (Cs-Cyj) cycloalkyl residue, a trifluoromethyl residue, a phenyl residue, or a benzyl residue;

[0016] or the residues R4 and Rs together represent the group -(CH2)r- and r represents an integer from 1 to 3; with the proviso that if this numerical value is 2 or 3, a benzene ring may also be fused to two adjacent CH2 groups; and with the further proviso that one of the CH2 units may be replaced by -C(CH3)2-, -C(C2HS)2- or -C(C6Hs)2-;

[0017] the residues Re, R7 and Rs each independently represent a substituent selected from hydrogen, a (Ci-Ce) alkyl residue, a (Cs-Cyj) cycloalkyl residue, a (Ci-Ce) alkoxy residue, a phenyl residue, a 4-methoxyphenyl residue, a 3,4,5-trimethoxyphenyl residue, a 4-(dimethylamino)phenyl residue, a 4-(N-morpholinyl)phenyl residue, a 4-(diphenylamino)phenyl residue, a 4-(trifluoromethyl)phenyl residue, a phenoxy residue or a benzyl residue;

[0018] or the residues Re and R7 together or R7 and Rs together form an annelated benzene ring which may be unsubstituted, mono- or disubstituted, wherein the substituents may be selected from hydrogen, a (Ci-Ce) alkyl residue, a (Ci-Ce) al-koxy residue, a phenyl residue or a benzyl residue;

[0019] or the residues Re and R7 together or R7 and Rs together form an fused naphthalene ring system, an fused benzofuran ring system, an fused benzothiophene ring system, an fused 3,3-dimethylindene ring system or an fused 2H-chromene ring system;

[0020] the residues R9, R10, R11, R and R14 each independently represent a substituent, selected from a (Ci-Cs) alkyl residue or a phenyl residue;

[0021] the residue R12 represents a substituent selected from a (Ci-Cs) alkyl residue, a phenyl residue or the group

[0022]

[0023] where s represents an integer between 0 and 1 and t represents an integer between 1 and 50.

[0024] Preferably the ratio of the two naphthopyrans of formulas (I) and (II) is between 1:10 and 10:1, more preferably between 1:5 and 5:1 and particularly preferably between 1:3 and 3:1.

[0025] Fig. 1 shows a synthesis scheme for the preparation of the compounds used according to the invention as well as the function of their excitation;

[0026] Fig. 2 shows VIS absorption spectra of the prior art compounds (EP 4 240797); Fig. 3 shows VIS absorption spectra of compounds according to the invention (double absorption bands); and

[0027] Fig. 4 shows an illustration of the darkening color tones of compounds used according to the invention in comparison to reference compounds from the prior art.

[0028] Fig. 5 shows the phototropic performance of two combinations according to the invention of the two homologous, photochromic annelated naphthopyrans according to the above general formulas (I) and (II).

[0029] According to the present invention, a novel combination of two special photochromic annelated naphthopyrans and their incorporation into polymers for phototropic products is provided. The two annelated naphthopyrans are homologous systems, meaning that the basic structure differs from each other by only one carbon atom at a specific molecular position (directly adjacent to the naphthalene subunit). This small difference is unexpectedly sufficient to produce very different darkening shades. Both photochromic annelated naphthopyrans are characterized by the fact that, in the darkened state, they each exhibit a pronounced double absorption band in the visible wavelength range. As a consequence, they each produce matte (i.e.,Non-brilliant darkening shades, with which aesthetically pleasing gray and brown mixed shades can be easily achieved in phototropic polymers when the two annelated naphthopyrans are combined in a suitable ratio. Furthermore, deeply darkening and very quickly lightening phototropic products are accessible in this way.

[0030] The compounds according to the invention are synthesized from the underlying fused naphthopyrans with a 4-hydroxy substituent (i.e., m = 0) or a 4-(2-hydroxyethoxy) substituent (i.e., m = 1) on the benzene ring bonded to the carbon atom adjacent to the pyran oxygen. The compounds according to the invention are prepared according to the synthesis scheme in Figure 1. The method is identical for formulas (I) and (II) – therefore, only the pyran ring with the two aryl substituents is shown in Figure 1.

[0031] In contrast to the use of the compounds according to the invention in polythiourethanes, the attachment of a longer poly(propylenoxy) chain in polymers produced from acrylate monomers is not absolutely necessary to achieve very good phototropic properties - compounds of formulas (I) and (II) with p = 0 are also well suited for this purpose.

[0032] For use in polythiourethanes, however, the attachment of a longer poly(propylene-enoxy) chain is necessary – there are two synthetic routes for this: If n represents 0, commercially available polypropylene glycol monobutyl ethers (with p > 10 in formulas (I) and (II), for example, p « 42 with an average molecular weight of 2500) are first activated as tosylate (Ts). The chain length in each case exhibits a Gaussian distribution, i.e., mixtures with different chain lengths are present, distributed around a maximum. Covalent attachment to the annealed naphthopyranes, which were previously activated by deprotonation with sodium hydride, is then achieved via a standard Williamson ether synthesis. If n represents 1, the reaction with succinic anhydride is performed first.After activation of the free carboxyl group of the succinyl unit with carbonyldiimidazole (CDI), a very mild ester synthesis with the hydroxy group of polypropylene glycol monobutyl ether can be achieved even at low reaction temperatures.

[0033] Similar compounds with the basic structure of formula (I) were first presented for use in plastics of all kinds in EP 3807258. In EP 4240797, these compounds (exemplary embodiments darkening to blue tones were presented) were combined with photochromic compounds with an isomeric basic structure that darken to orange tones to realize gray- and brown-darkening phototropic products. The compounds of formula (I) according to the invention have a more narrowly defined substitution pattern at two positions compared to formula (I) from EP 4240797. To achieve the desired double absorption properties, two alkoxy substituents are essential, i.e., one oxygen atom together with the substituents R4 and Rs. The compounds of formula (II) according to the invention have a basic structure reduced by one carbon atom compared to (I) (the carbon atom with the substituent Rn is missing), i.e.,(I) and (II) are therefore homologous systems. Analogous to (I), the presence of two alkoxy substituents at the same position in the molecule is also essential for the compounds of formula (II) according to the invention. Compounds of formula (II) (i.e., m = n = p = 0) were first presented in EP 1 214311.

[0034] Surprisingly, the combination of compounds according to formula (I) with homologous compounds according to formula (II) is characterized by the fact that aesthetically pleasing gray and brown darkening shades can be easily achieved in phototropic polymers, which are very stable with regard to hue consistency during darkening and lightening, as well as longevity. This is due to the presence of a pronounced double absorption band in the visible wavelength range of the electromagnetic spectrum in the darkened state. Although the basic structure of the compounds according to the invention of formulas (I) and (II) differs by only one carbon atom, this small difference is unexpectedly sufficient to produce completely different shades. These darkening shades are non-brilliant (i.e., not very bright) due to the double absorption band.for example not intense orange or intense blue as presented in EP 4240797), but matte (for example bluish-grey or reddish-brown), which makes it much easier and with fewer restrictions to achieve aesthetic grey and brown mixed colour tones.

[0035] Photochromic polymers combining these two fused naphthopyrans are characterized by very stable and aesthetically pleasing darkening shades. Furthermore, this combination allows for the creation of deeply darkening and very quickly lightening photochromic products. In addition, this combination exhibits excellent durability in photochromic plastic spectacle lenses.

[0036] Suitable polymer systems for this purpose are primarily polythiourethanes, polyurethanes, and polymers made from acrylate monomers. To obtain the best possible phototropic properties (i.e., darkening depth, lightening rate, and lifetime stability) for each polymer matrix, the substituents and the coefficients m, n, and p in formulas (I) and (II) are optimally adapted to the respective matrix.

[0037] Polythiourethanes are by far the most widely used materials for plastic spectacle lenses with higher refractive indices of >1.60. The higher the refractive index, the thinner a corrective lens can be. As already explained in EP 4240 797, the presence of a longer poly(propylenoxy) chain covalently bonded to the dye backbone is necessary for the use of polythiourethanes to achieve excellent photochromic properties. This is because the very dense polythiourethane thermosets used for ophthalmic purposes do not allow conventional photochromic dyes any space to open from the colorless naphthopyran form to the open (colored) merocyanine form through long-wave UV radiation (e.g., sunlight; see Figure 1 below). Therefore, no or only extremely weak darkening is observed upon irradiation with long-wave UV light.In contrast, the fused naphthopyrans according to the invention exhibit excellent darkening depth upon irradiation with long-wave UV light due to the covalently bonded longer poly(propylene-oxy) chain (with p > 10 in formulas (I) and (II)). Evidently, the presence of the longer poly(propylene-oxy) chain modifies the immediate dye environment either sterically (change in the surrounding network density) or electronically (change in the surrounding polarity) such that the opening of the unexcited (colorless) form to the open (colored) form by long-wave UV radiation becomes readily possible. The long poly(propylene-oxy) chain is located close to the photolabile center of the photochromic dye and thus close to the site of bond cleavage upon excitation or bond regeneration upon lightening (see Figure 2 below), and can therefore provide efficient shielding from the thiourethane polymer.

[0038] Regarding the length of the poly(propylenoxy) chain, it should be noted that below a poly(propylenoxy) chain length of about 10 (p < 10) a significant decrease in the phototropic performance can be observed; the shielding of the dye from the polythiourethane environment is then obviously no longer effectively possible.

[0039] The poly(propylenoxy) chain in the compounds of formulas (I) and (II) according to the invention is either directly (i.e., n = 0) or via a succinyloxy bridge (i.e., n = 1) bonded to the dye backbone. For reasons of synthesis efficiency and lightening speed (see Table 1), it is often more advantageous to introduce an additional glycol bridge (i.e., m = 1).

[0040] The compounds of formula (I) according to the invention exhibit matte reddish (F = H) to matte violet (R2 = diarylamino) darkening hues, depending primarily on the donor properties of the substituent F. Phenoxy and especially alkoxy groups prove to be the most suitable substituents F, since these substituents generate matte reddish-brown darkening hues, making it very easy to achieve aesthetically pleasing gray and brown mixtures (see compound 1 according to the invention).

[0041] The compounds of formula (II) according to the invention exhibit - also depending primarily on the donor properties of the substituent R2, but with a wider color range - matt yellowish-olive (R2 = alkoxy; see compound 2 according to the invention) to matt bluish-grey (R2 = diarylamino; see compound 3 according to the invention) darkening shades.

[0042] In a direct comparison of the two homologs with only hydrogen as the substituent R2, the compounds according to formula (I) light up significantly more slowly than the compounds according to formula (II) – another unexpected difference between the homologous systems besides the different color shades. This will be explained in more detail later.

[0043] In contrast, the compounds according to the invention from EP 4 240 797 exhibit brilliant darkening colors (intense orange tones or intense blue tones), since they each have only one absorption band in the visible wavelength range in the darkened state, whereas the compounds used according to the invention have a double absorption band.

[0044] This difference is clearly illustrated in Figures 2 and 3. Figure 2 shows the prior art reference compounds 1 (orange; compound 4 from EP 4 240 797) and 2 (blue; compound 2 from EP 4240797) with only one absorption band. Figure 3 shows three new compounds used according to the invention, each with a double absorption band. The exact molecular structures of compounds 1 (from formula (I)) and 2 and 3 (from formula (II)) used according to the invention are listed in Table 1.

[0045] As can be seen in Figure 2, the compounds used according to the invention have two absorption maxima (or transmission minima) in the visible wavelength range and generally absorb over a significantly wider range - resulting in matte darkening tones, which makes it very easy to achieve aesthetically pleasing grey and brown mixed tones.

[0046] The combination according to the invention is also particularly advantageous because it is relatively easy to match the lightening rates by choosing suitable substituents (see Table 1) - this is crucial for use in mixtures so that the darkening hue remains constant over the entire excitation and lightening cycle.

[0047] The compounds used according to the invention, as described in formulas (I) and (II), exhibit excellent lifetime stability against UV radiation – due to the presence of the three non-hydrogen substituents Rg to Ru at the two non-aromatic carbon atoms in formula (I) and the two non-hydrogen substituents R13 and Ru in formula (II). The former was already described in EP 4240797; corresponding compounds with fewer non-hydrogen substituents at these positions exhibit a significantly shorter lifetime due to the easier oxidizability at this location and the formation of colored oxidation products. Three non-hydrogen substituents in formula (I) represent the optimum.A hydrogen atom on the carbon atom with Ru in formula (I) is necessary for steric reasons, since another non-hydrogen substituent on the carbon atom with Ru sterically hinders the opening of the colorless naphthopyran form to the open (colored) form by long-wave UV radiation too much, and thus only a weak darkening can be observed when irradiated with long-wave UV light.

[0048] The excitation process (bond cleavage by long-wave UV light resulting in the colored form) is also illustrated in Figure 1. The reversion to the non-excited naphthopyran form occurs purely thermally; therefore, at higher temperatures, fewer molecules are present in the darkened state on average, as the reverse reaction is faster. This results in the temperature dependence of the darkening depth typical for photochromic plastic lenses. At the same UV intensity, the darkening depth is inversely proportional to the temperature. However, the proportionality factor—i.e., the strength of this dependence—can be influenced to some extent by the choice of substituents.

[0049] To measure the phototropic and spectral properties (see Figure 3 and Table 1), the compounds of formulas (I) and (II) according to the invention were incorporated into an optical thiourethane polymer, i.e., one suitable for commercial plastic spectacle lenses. For this purpose, the photochromic dyes were dissolved in the liquid isocyanate component and, after addition of the thiol component and the polyaddition catalyst, thermally polymerized using a temperature program.

[0050] Phototropic performance (darkening depth and lightening rate) and darkening color point (see Figure 4) of the test specimens produced in this way (planar glass with 2 mm thickness) were subsequently determined using standard measurements at 23°C according to DIN EN ISO 8980-3.

[0051] Figure 4 clearly shows a comparison of the darkening color coordinates in a* / b* color coordinates of compounds according to the invention against prior art reference compounds. The molecular structures of the compounds according to the invention shown in Figure 4 are listed in Table 1. Compounds 1, 4, 5, and 6 according to the invention are described by formula (III), and compounds 2, 3, and 7 according to the invention by formula (IV). Formula (III) represents a subgroup of (I), and formula (IV) a subgroup of (II).

[0052] A negative a* value in the a* / b* color coordinate system represents a greenish tint, a positive a* value a red one. A negative b* value represents a blue tint, a positive b* value a yellow one. Derived mixed colors such as violet or orange are then found in the area between the respective semi-axes (i.e., between the blue and red semi-axes and the yellow and red semi-axes, respectively). The further the measurement point is from the origin of the coordinate system, which by definition represents the absence of color, the more intense and vibrant the tint. Measurement points near the origin of the coordinate system (region A represents particularly aesthetically pleasing shades of gray) symbolize matte shades such as bluish-gray or reddish-brown. A special case are brown shades that are a mixture of different primary colors. Empirical studies have shown that aesthetically pleasing brown shades (e.g.,chestnut brown) in the a* / b* color coordinate system in the area of ​​region B.

[0053] The reddish-brown darkening hue of compound 1 of formula (III) according to the invention is already close to this region B – significantly closer compared to the intensely orange reference compound 1 (compound 4 from EP 4240797). By combining it with the yellowish-olive darkening hue of compound 2 of formula (IV) according to the invention in a suitable mixing ratio, aesthetically pleasing brown hues of region B can be achieved very easily.

[0054] Similarly, the bluish-gray darkening hue of compound 3 of formula (IV) according to the invention is already close to region A, which represents aesthetic gray tones; again, significantly closer compared to the intensely blue reference compound 2 (compound 2 from EP 4240797). By combining it with the reddish-brown darkening hue of compound 1 of formula (III) according to the invention in a suitable mixing ratio, aesthetic gray tones of region A can be achieved very easily; sometimes the addition of a small amount of compound 2 of formula (IV) according to the invention is also advantageous.

[0055] The brightening behavior from the completely darkened state of the compounds according to the invention is also listed in Table 1. The measure of the brightening behavior is defined as the percentage relative increase in transmission after 2 minutes of brightening, normalized to the total photochromic range of complete brightening. This practically relevant parameter for describing the photochromic kinetics is here referred to as Relative Brightening F ≤ 2 min.

[0056] R2min = 100 X X2 min _~ Ts [%]

[0057] T 0 s

[0058] wherein

[0059] to the light transmittance in the unexcited state;

[0060] t s the light transmittance in the darkened state;

[0061] t2min is the light transmittance after 2 minutes of brightening from a darkened state.

[0062] The stated percentage value is calculated from the transmission data of the phototropic kinetic measurement according to DIN EN ISO 8980-3 at 23°C. In the first step, the transmission difference between the state after 2 minutes of brightening and the previously achieved darkened state is determined; in the second step, the transmission difference between the brightened and darkened states is determined. The ratio of the two transmission differences is multiplied by 100 to obtain a percentage value. A value of 50% for R2 min means that after 2 minutes of brightening, half of the photochromic stroke to the fully brightened state has already been completed. The higher the percentage value, the faster the brightening process.

[0063] Table 1

[0064] Molecular structures of the compounds shown in Figures 3 and 4 according to formulas (III) and (IV) and their brightening rate after 2 min at 23°C in the thiourethane polymer:

[0065]

[0066]

[0067]

[0068]

[0069] When combining compounds of formulas (III) and (IV) in dye mixtures, it is important that the lightening rates of the components are matched; otherwise, an undesirable color drift will occur during lightening. Therefore, compounds 1, 2, and 3 according to the invention are perfectly matched components for dye mixtures with aesthetically pleasing gray and brown darkening tones.

[0070] Excellent, fast-lightening, photochromic plastic spectacle lenses currently available commercially exhibit an excellent F2 min value of approximately 50% after 2 minutes of lightening; i.e., by suitable combination of the inventive compounds 1, 2 and 3, it is possible - as already explained - to relatively easily realize excellent photochromic plastic spectacle lenses with aesthetic grey and brown hues that lighten very quickly with excellent darkening depth.

[0071] The slower-brightening compounds 5, 6, 7 and 8 according to the invention can be used in special photochromic plastic spectacle lenses for warmer climates, since these darken to a greater extent at higher temperatures due to the slower reverse reaction compared to the compounds 1, 2 and 3 according to the invention (see Figure 1 below), as more dye molecules are present in the darkened (open) state.

[0072] Adjusting the desired brightening rate is relatively easy by varying the substituents in formulas (I) and (II). There are several levers for this:

[0073] The first determining factor is, unexpectedly, the type of alkyl substituent R4 or Rs – this is clearly demonstrated by comparing compounds 1 and 4 according to the invention, and compounds 7 and 8 according to the invention. Compounds with an ethylene bridge for R4 / R5 – resulting in an fused dioxane ring – lighten significantly more slowly compared to compounds with two separate alkyl substituents for R4 and Rs. This is completely unexpected, since both the electronic effect (donor strength) and the steric effect (spatial size) should not differ significantly from each other. This effect can be observed for compounds of formula (I) as well as (II). Consequently, while compound 4 according to the invention lightens extremely quickly, it does not darken deeply enough under UV irradiation for excellent photochromic plastic spectacle lenses, because the reversal reaction to the colorless ground state is too rapid.

[0074] Unexpectedly, compounds of formula (II) with an identical substitution pattern R2 to Rs lighten significantly more slowly after UV exposure compared to compounds of formula (I). Therefore, in contrast to compound 4, compound 2 according to the invention, with two separate alkyl substituents for R4 and Rs, does not lighten too quickly and generates excellent depth of darkening with very rapid lightening.

[0075] The second lever point is the electronic effect of the donor strength of substituent R2 – this is clearly illustrated by comparing compounds 1 and 5 according to the invention, and compounds 2 and 3 according to the invention. The stronger the donor R2, the faster the photochromic dye lightens after UV exposure. This fact is not new, but has already been observed in many earlier photochromic naphthopyran systems. To prevent compound 3 according to the invention with the very strong diarylamine donor from lightening too quickly and thus darkening too weakly, a third lever point (a steric effect) can be exploited, which, however, only exists in compounds of formula (II) – the size of substituents R13 and R14. The larger these substituents and their steric effects are, the faster the photochromic dyes lighten.Therefore, reducing the size of these substituents in compound 3 according to the invention, compared to compound 2 according to the invention (from propyl to ethyl), compensates for the effect of the stronger donor for R2 with regard to faster lightening and weaker darkening depth. However, if the substituents become even smaller (methyl), the photochromic dyes generally lighten significantly too slowly. This third point of leverage does not exist in compounds of formula (I), since – as already explained – a hydrogen atom must be attached to the carbon atom with R11 in order to achieve sufficient darkening depth.

[0076] The fourth and final lever point is the coupling of the poly(propylenoxy) chain via the succinyloxy group (in the case of n = 1) directly to the naphthopyran backbone (i.e., m = 0) or via an additional glycol bridge (i.e., m = 1) – this is clearly illustrated by comparing compounds 1 and 6 according to the invention. Photochromic dyes without a glycol bridge (i.e., m = 0) lighten significantly more slowly – the reason for this, analogous to the second lever point, lies in the difference in the donor strength of the substituent directly covalently bonded to the benzene ring. Compounds with the stronger alkoxy donor (i.e., m = 1) lighten significantly faster compared to compounds with the weaker acyloxy donor (i.e., m = 0).

[0077] With these various leverage points, a comprehensive repertoire is available to tailor the desired phototropic properties in order to generate suitable partners for the combination according to the invention. Table 2

[0078]

[0079] Table 2 shows two examples of combinations according to the invention of the compounds 1 to 3 according to the invention, which achieve aesthetic grey and brown colorations.

[0080] The proportions given in the table refer to the total dye concentration of 2000 ppm in the thiourethane matrix.

[0081] The table value "To" represents the transmission in the unshaded state of the test specimen, "Ts" represents the transmission in the darkened state of the test specimen after darkening in standard measurements at 23°C according to DIN EN ISO 8980-3. The "R 2min" value represents the relative brightening after a 2-minute brightening time, as explained in more detail above.

[0082] As can be seen from Table 2, the combination according to the invention No.

[0083] 1. Excellent transmission in the undarkened state and very good darkening depth after illumination. With a relative lightening of 62% after 2 minutes, this combination is also ideally suited for modern photochromic lenses. The darkening color point (a* / b* = -1.2Z-3.4), also determined during standard measurement, corresponds to a pleasantly neutral gray tone and lies within the "aesthetic gray region" sketched in Figure 4 (see also Figure 5).

[0084] The combination according to the invention No. 2 in Table 2 also shows excellent transmission in the non-darkened state and good darkening depth for brown test specimens after illumination. With a relative lightening of 50% after 2 minutes, this combination is also well suited for modern photochromic spectacle lenses. The darkening color point (a* / b* = 6.6 / 20.5) also determined in the standard measurement corresponds to a pleasant reddish-brown tone and is located within the “aesthetic brown region” sketched in Figure 4 (see also Figure 5).

[0085] In summary, the examples shown demonstrate that excellent results for gray and brown photochromic lenses can be achieved using a combination of just two photochromic dyes. However, when using photochromic dyes with brilliant darkening colors, achieving these product properties would require a combination of more than two photochromic dyes.

[0086] The scope of the present invention is not limited to homogeneously mass-dyed phototropic polythiourethanes, polyurethanes, and polymers made from acrylate monomers, but also includes, in particular, two-component systems in which a 0.1–1 mm thin phototropic polymer functional layer is polymerized onto a polymer substrate (casting process). Besides attractive manufacturing costs, this process has the significant advantage that, unlike homogeneously mass-dyed products, excellent UV protection for the wearer of eyeglasses can be easily achieved by incorporating any desired amount of UV absorber into the polymer substrate. This is not possible with homogeneously mass-dyed phototropic polymers, since incorporated UV absorbers filter out the long-wave UV light required for darkening by the photochromic dyes.The present invention also includes sandwich systems in which a 0.1-1 mm thin phototropic polymer functional layer is located between two polymer bodies.

[0087] Furthermore, the scope of the present invention is not limited to the presence of the two naphthopyran homologs according to formulas (I) and (II). In addition, further tailored photochromic dyes, permanent dyes (for pre-colored products), and additives, in particular those for improving product properties, can be used. The scope of the present invention also includes the use of the combination of fused naphthopyran homologs according to the invention in polymers for photochromic products, in particular for ophthalmic purposes, in lenses and glasses for spectacles of all kinds, such as prescription glasses, driving glasses, ski goggles, sunglasses, motorcycle goggles, for visors of protective helmets and the like, and for sun protection purposes in vehicles and in the construction sector, in the form of windows, protective screens, covers, roofs, and the like.

Claims

Claims 1. Combination of two homologous, photochromic annelated naphthopyrans according to the following general formulas (I) and (II): where in formulas (I) and (II) m is an integer between 0 and 1, n is an integer between 0 and 1, and p represents an integer between 0 and 50; the residues Ri, R2 and R3 each independently represent a substituent selected from hydrogen, bromine, chlorine, fluorine, a (Ci-Ce) alkyl residue, a (C3-C7) cycloalkyl residue, a (Ci-Cej) thioalkyl residue, a (Ci-Ce) alkoxy residue, a trifluoromethyl residue, a phenyl residue, a 4-methoxyphenyl residue, a phenoxy residue, a 4-methoxyphenoxy residue, a benzyl residue, a 4-methoxybenzyl residue, a benzyloxy residue, a 4-methoxybenzyloxy residue, a biphenyl residue, a biphenyloxy residue, a naphthyl residue, a naphthoxy residue, a di-(Ci-Cej) alkylamino residue, a piperidinyl residue, a 3,5-dimethylpiperidinyl residue, an indolinyl residue, a morpholinyl residue, a 2,6-dimethylmorpholinyl residue, a thiomorpholinyl residue, an azacycloheptyl residue, a phenylamino residue, a (Ci-Cej-alkylphenylamino residue, a diphenylamino residue, a (4-methoxyphenyl)phenylamino residue,a bis(4-methoxyphenyl)amino residue, a (4-ethoxyphenyl)phenylamino residue, a bis(4-ethoxyphenyl)amino residue, a 10,10-dimethyl-9,10-dihydroacridine residue, a phenothiazinyl residue, a phenoxazinyl residue, a phenazinyl residue, a carbazolyl residue, a 1,2,3,4-tetrahydrocarbazolyl residue or a 10,11-dihydro-dibenz[b,f]azepinyl residue; or the residues Ri and R2 together represent the group -X-(CH2)qY-, wherein X and Y are independently selected from the groups -0-, -S-, -N(Ci— Ce)-alkyl, -NCeHs-, -CH2-, -C(CH3)2-, -C(C2HS)2- or -C(C6Hs)2- and q is an integer from 1 to 3; with the proviso that if this numerical value is 2 or 3, a benzene ring may also be fused to two adjacent CH2 groups; and with the further proviso that if X or Y represent -CH2-, they may also represent a fused benzene ring together with the respective adjacent CH2 group; the residues R4 and Rs each independently represent a substituent, selected from a (Ci-Ce) alkyl residue, a (Cs-Cyj) cycloalkyl residue, a trifluoromethyl residue, a phenyl residue, or a benzyl residue; or the residues R4 and Rs together represent the group -(CH2)r- and r represents an integer from 1 to 3; with the proviso that if this numerical value is 2 or 3, a benzene ring may also be fused to two adjacent CH2 groups; and with the further proviso that one of the CH2 units may be replaced by -C(CH3)2-, -C(C2HS)2- or -C(C6Hs)2-; the residues Re, R7 and Rs each independently represent a substituent selected from hydrogen, a (Ci-Ce) alkyl residue, a (Cs-Cyj) cycloalkyl residue, a (Ci-Ce) alkoxy residue, a phenyl residue, a 4-methoxyphenyl residue, a 3,4,5-trimethoxyphenyl residue, a 4-(dimethylamino)phenyl residue, a 4-(N-morpholinyl)phenyl residue, a 4-(diphenylamino)phenyl residue, a 4-(trifluoromethyl)phenyl residue, a phenoxy residue or a benzyl residue; or the residues Re and R7 together or R7 and Rs together form an annelated benzene ring which may be unsubstituted, mono- or disubstituted, wherein the substituents may be selected from hydrogen, a (Ci-Ce) alkyl residue, a (Ci-Ce) al-koxy residue, a phenyl residue or a benzyl residue; or the residues Re and R7 together or R7 and Rs together form an fused naphthalene ring system, an fused benzofuran ring system, an fused benzothiophene ring system, an fused 3,3-dimethylindene ring system or an fused 2H-chromene ring system; the residues R9, R10, R11, Ris and R14 each independently represent a substituent, selected from a (Ci-Cs) alkyl residue or a phenyl residue; the residue R12 represents a substituent selected from a (Ci-Cs) alkyl residue, a phenyl residue or the group where s represents an integer between 0 and 1 and t represents an integer between 1 and 50.

2. Combination according to claim 1, wherein the ratio of the two naph-thopyranes of formulas (I) and (II) is between 1:10 and 10:1, preferably between 1:5 and 5:1, and particularly preferably between 1:3 and 3:

1.

3. Combination according to claim 1 or 2 for incorporation into polythiourethanes, wherein p is an integer between 10 and 50.

4. Combination according to any one of claims 1 to 3, further comprising one or more additional components selected from photochromic dyes, different from those of formulas (I) and (II), permanent dyes or additives.

5. Combination according to any one of claims 1 to 4, wherein the phototropic products are two-component systems in which a 0.1-1 mm thin phototropic polymer functional layer is polymerized onto a polymer substrate, or sandwich systems in which a 0.1-1 mm thin phototropic polymer functional layer is located between two polymer bodies.

6. Use of the combination according to any one of claims 1 to 5 in polymers for phototropic products, in particular for ophthalmic purposes, in lenses and glasses for spectacles of all kinds, such as prescription glasses, driving glasses, ski goggles, sunglasses, motorcycle goggles, for visors of protective helmets and the like, and for sun protection purposes in vehicles and in the construction sector, in the form of windows, protective screens, covers, roofs and the like.

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