Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K9/00—Tenebrescent materials, i.e. materials for which the range of wavelengths for energy absorption is changed as a result of excitation by some form of energy
  • C09K9/02—Organic tenebrescent materials
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
  • G02B1/041—Lenses
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/20—Filters
  • G02B5/22—Absorbing filters
  • G02B5/23—Photochromic filters

Definitions

• the present invention relates to a neutral-colored gray photochromic plastic object which remains almost completely neutral or gray both during the darkening and during the lightening.
• the plastic object according to the invention can be used in particular as a neutral-colored gray photochromic spectacle lens.
• Photochromic plastic products especially eyeglass lenses, have been on the market since the 1980s.
• Glass Perfalit Colormatic new since 1 995) already contained pyrans in addition to spiro-oxazines and / or fulgides.
• the products currently commercially available such as glass Transitions III, preferably use pyrans, especially naphthopyrans and larger ring systems derived from them.
• the Transitions II I products with the refractive index 1, 56 are based on US 5,753, 1 46.
• US 5,753,146 relates to compositions comprising at least two photochromic naphthopyran compounds which are free of amino-substituted aryl groups on the carbon atom which is adjacent to the oxygen atom of the pyran ring.
• these compositions When activated in a suitable carrier and exposed to ultraviolet solar radiation, these compositions are said to have a gray or brown neutral color when activated, which in the a * and b * ranges from + 10 to -10 of the CIELAB- Color system is included.
• Measurements of the glasses described as prior art in US Pat. No. 5,753,146 have shown that their color position in the darkened state is a * ⁇ + 8undb * ⁇ +4. In the brightening phase, even
• the present invention is therefore based on the object of providing a color-neutral gray photochromic plastic object which is almost completely color-neutral, i.e. during the darkening and during the lightening. remains gray.
• a color-neutral or gray photochromic plastic object which, when introduced, comprises at least two different photochromic color centers from the class of benzopyrans and higher, fused ring systems derived therefrom, the object being distinguished by the fact that it lasts for 15 minutes Exposure with 50 klux at 23 ° C according to prEN 8980 and a 1 5-minute lightening in the dark only goes through color locations whose chroma is C * ⁇ 8, preferably C * ⁇ 6, more preferably C * ⁇ 5.
• the color locus of the plastic object after a 15-minute exposure to 50 klux at 23 ° C. according to prEN 8980, has a C * value ⁇ 5, preferably C * ⁇ 4, more preferably C * ⁇ 3 , on.
• the spectral transmission of the object according to the invention is in the range from 400 to 650 nm in the darkened state after exposure for 1 5 minutes with 50 klux at 23 ° C. according to prEN 8980, preferably below 25%, more preferably below 20%.
• the spectral transmission of the object according to the invention at 700 nm in the darkened state after exposure for 15 minutes with 50 klux at 23 ° C. according to prEN 8980 is preferably below 50%.
• the transmission is as constant as possible in the central area of the visible.
• the spectral transmission difference in the range from 41 5 to 640 nm in the darkened state after 15 minutes of exposure to 50 klux at 23 ° C. according to prEN 8980 should be, for example, less than 10%, more preferably less than 8%.
• the spectral transmission according to V ⁇ in the completely deactivated state is preferably over 80% with a material thickness of 2 mm without antireflection coating.
• Photochromic glasses are all-round glasses, ideally they should replace both a colorless glass and a sun protection glass. This results in the requirement for the highest possible transmission without light excitation, e.g. at night. With anti-reflective coating, the aforementioned value enables transmission values close to or around 90%.
• the plastic object according to the invention can be used as an optical element, such as a lens, whose refractive index, measured with the Na-d line, is between 1.49 and 1.76.
• the plastic object according to the invention is used as a spectacle lens.
• Fig. 1 shows the absorption in the visible spectral range of a typical example according to the invention after 15 minutes of darkening with 50 klux at 23 ° C. according to the measurement method described in prEN 8980.
• Fig. 2 shows the color locus in the a * -b * color space of the CIELAB system for a typical example according to the invention in comparison with the color locus in example 4 of US Pat. No. 5,753,146 (corresponds to the glass transition gray 1, 56) during a 1st 5-minute exposure with 50 klux according to prEN 8980 and a 1 5 minutes of lightening in the dark at 23 ° C.
• a photochromic plastic article is provided for the first time, which is almost completely color-neutral, i.e. during the darkening and during the lightening. actually stays gray throughout.
• the present invention is based on the consideration of specific selection parameters with regard to the photochromic dyes to be used in a photochromic plastic glass.
• a neutral-colored gray photochromic plastic object has, for example, the one shown in FIG. 1 reproduced spectral absorption in the visible spectral range after 1 5-minute darkening with 50 klux at 23 ° C according to the measurement method described in prEN 8980.
• the spectral transmission difference is less than 1 0%, this condition is also with a tolerance of the limits of ⁇ 1 0 nm during the
• the neutral-colored impression can also be achieved, for example, with a range reduced to 600 nm.
• the color location of a photochromic plastic glass that contains more than one photochromic dye also depends on the spectral composition of the excitation light. This applies not only in the excitation phase (direct sunlight or scattered light), but also in the brightening phase for the residual light.
• a standard is used below which is independent of all eventualities at the measurement location, such as the time of year and day, latitude, altitude, weather and climate conditions etc.
• the analysis of the transmission light using a diode array and EDP - as described in more detail in the technical section of prEN 8980 - allows the transmission and the color location to be determined every 3 seconds.
• a color-neutral gray photochromic plastic object is one whose color location is constantly close to the zero point during the darkening and brightening described. All 4 quadrants of the CIELAB color system are preferably run through here. This can be done clockwise or counterclockwise or in a loop movement (shape of an eight). Since the starting point is usually only reached again by special measures (eg baking out) and not lightened within 15 minutes at 23 ° C, the color locus is usually not closed. The ideal case of a circle concentric around the zero point is not attainable, rather the shape of the color locus movement is mostly ellipsoid, square or diamond-shaped. The C * value is important for the neutral gray color.
• the invention has a C * value that does not exceed 8 at any point in the cycle described.
• the color-neutral gray photochromic plastic object according to the present invention preferably has a C * value of C * ⁇ 6, more preferably C * ⁇ 5.
• the color-neutral gray photochromic plastic object has a color location after a 15-minute period
• a neutral hue in additive mixing results from the mixing of at least two colors. If there are only two colors, these should be approximately complementary, i.e. the absorptions of the photochromic dyes or their maxima in the visible spectral range must be shown in the UCS color table of CIE 1 976 for 2 ° normal observers by a the "Weissfeld" straight line can be connected. With only two dyes, this means that the absorption maximum of one dye should be below approximately 495 nm, that of the other should be above approximately 570 nm. The difference between the absorption maxima of possible combinations results in values of approx. 1 00 to 1 30 nm.
• pyrans Decisive for the true color locus of color-neutral gray glasses is not only the position of the absorption maximum, but the band shape of the absorption in the visible spectral range.
• pyrans have a very broad “soft” structure-free absorption band in the visible spectral range.
• various pyrans for example those described in WO 98/28289, have two absorption bands in the visible spectral range, the shorter-wave ones having almost the same intensity as the longer-wave ones.
• These compounds are preferably used when the second dye is to have a clear absorption even in the very long-wave visible spectral range around 700 nm. If such a broad absorption is desired, three or more photochromic compounds are preferably used.
• UV absorption is of crucial importance. UV does not only mean the pure UV range up to 380 nm, but also the very short-wave visible light up to about 400 nm. The location of the UV maximum is less so than
• the shape of the UV absorption bands is crucial.
• the absorption and concentration of the dyes must be selected in such a way that no dye alone takes up more than 60% of the intensity of the excitation light above 380 nm.
• a photochromic dye is already a neutral-colored glass possible. This has the additional advantage that all factors that impair a neutral color during the darkening and brightening, such as different darkening and brightening speeds, are excluded. In this case, the color is not influenced by the temperature (no different temperature dependency) or the spectral composition of the excitation light (no different excitation spectra).
• photochromic plastic glasses can be manufactured in three different ways.
• the photochromic dyes can be distributed homogeneously in the mass of the plastic glass.
• they can (usually only on the convex side) be introduced into the surface of the plastic glass using heat by diffusion.
• they can be applied in a layer on the plastic glass. Concentrations can be determined for the former and the latter type of production according to the individual data of the individual photochromic dyes, for diffusion-colored ones
• the ideal solution for providing a neutral-colored gray photochromic plastic object would be a single photochromic dye with the corresponding absorption properties.
• all the problems mentioned below would also be
• a glass is colored with two pyrans, which have similar absorption maxima in the UV range, saturation absorptions, darkening and brightening rates and their long-wave absorption maximum at 425 nm and 540 in the visible spectral range nm, a particularly preferred example.
• such a glass is never gray or brown, but red to red-violet. It is completely ignored in US Pat. No. 5,753,146 that pyrans in particular with ⁇ max > 525 nm are often distinguished by two or more absorption maxima in the visible spectral range. These must be taken into account if their intensity is more than approx. 50% of the main band.
• the individual dyes to be used must be tested in the plastic in which the
• the selection must then be made according to the spectral absorption behavior in the UV range.
• the absorption (extinction) in the unexposed state is assessed. Since some of the photochromic dyes in question still absorb well beyond the UV limit, which is generally applied at 380 nm, the UV range here means the wavelength range ⁇ 41 0 nm, in which the spectral sensitivity to light of the average human eye is still below about 0.1% of the maximum value.
• the absorption function is folded with the spectral distribution of the solar radiation E sA ( ⁇ ) if the use of the photochromic plastic object under natural sunlight is the main application. You can do this from the values
• the absorption behavior in the visible spectral range is then used to produce a plastic object according to the invention.
• the absorption range can be determined, in which the absorption ⁇ OD min. 80% of the / l max VIS value.
• the dyes are selected such that the absorption ranges cover the spectral range from 420 to 600 nm in such a way that the differences and / or overlaps at the limits are ⁇ 10 nm.
• absorption envelopes are to be calculated for dyes whose ⁇ ma) NIS difference is ⁇ 50 nm. These can be treated like the absorption curves of the individual dyes.
• the saturation absorption is not of the importance as described in US Pat Mix can be adjusted. It is also a function of the lightening speed, i.e. slower brightening photochromic dyes always have higher ⁇ OD values in saturation than faster brightening dyes of a related structure. Since inefficient photochromic dyes cannot be used economically, commercially available dyes in ⁇ OD shifttt only differ by a maximum of about a factor of 2, as is also shown in Table 1 in US Pat. No. 5,753,146. Since the absorption is an exponential function for concentration according to the Lambert-Beer law, this can be achieved with small concentration variations (at least as long as you are still in the approximately linear range).
• the procedure can be such that the time in which the photochromic dye in question reaches 50% of the final value is evaluated.
• the faster (fastest) darkening Dye should not undercut the slower (slowest) darkening dye by more than about 30%.
• the coincidence of the lightening times is extremely important.
• the lightening or half-life is the time that the dye in the plastic article needs at 23 ° C to reach half the absorption difference between the unexposed state and the state after 15 minutes of exposure.
• the relative difference should not exceed 25%.
• the absolute value or the absolute difference is meaningless for the neutrality of the color, rather the intended use of the plastic object determines the framework for the absolute value of the brightening rate.
• Fig. 2 is the color locus in the a * -b * color space of the CIELAB system for a typical example according to the invention (mass-colored in the plastic material TS-1 50 from Tokuyama) and for example 4 from US Pat. No. 5,753, 1 46 as a representative comparative example (surface-colored in CR-407 from PPG) during a 1-minute exposure to 50 klux according to prEN 8980 and a 1 5-minute lightening in the dark at 23 ° C.
• the color C * of the comparative example is 1 0.5 in the fully darkened state, whereas the value of the example according to the invention is C * ⁇ 3. Furthermore, a C * value of 5 is never exceeded during darkening and brightening.
• the plastic object according to the invention contains one or more plastic materials as a carrier or matrix for the photochromic dyes to be used or used.
• the plastic materials used can be the plastics which can usually be used in the prior art, in particular for ophthalmic purposes.
• the plastic material made of poly (C 1 -C 12 alkyl) methacrylates, polyoxyalkylene methacrylates, polyalkoxyphenol methacrylates, cellulose acetate, cellulose triacetate, cellulose acetate propionate,
• Plastic object is provided to be measured.
• the test specimens for the characteristic values can be produced in different ways.
• the following method has proven to be particularly advantageous.
• the dyes are the finished cast resin batch (monomers, initiator, possibly additives such as antioxidants, UV absorbers) in a concentration of 0.01 to 0.1 wt .-%, preferably 0.03 to 0.06 wt .-%, admitted.
• the polymerization of these test specimens takes place in the same polymerization program that is intended for the final plastic object.
• the dyes must be mixed in the same way in a cast resin batch without additives.
• the concentration depends on the thickness of the coating. For example, 2 wt.
• the product of the concentration of the dye in the fully cured layer in% of the layer weight and the layer thickness should preferably have the value 4 x 10 "7 m. If photochromic surface coloring by thermal diffusion is provided for the plastic object, the concentration is only directly with enormous effort to determine, for example by quantitative analysis or by UV absorption of concentration series, but it has proven to be sufficient to adjust the dyeing conditions (temperature program) for a dye whose absorption maximum is in the visible spectral range at about 550 nm so that the test specimen before and after standard exposure one
• test specimens are measured, as described in the experimental part of prEN 8980, in a kinetic bench.
• the measuring light passing through the test specimen should be able to be analyzed in quick succession for transmission and color location, e.g. using a diode array spectrometer.
• the result of this measurement is the color location of the test specimen before the exposure and at any time during the exposure and the brightening phase. This usually takes place in the dark.
• this can also be done under standard type A (incandescent lamps) or under weakened exposure (shadow condition)
• a spectral analysis is carried out at least before the exposure, at the end of the exposure and at the end of the measurement, that is to say an absorption spectrum in the range from about 350 to 800 nm is recorded.
• the conditions for simulating natural lighting by sunlight such as
• the temperature dependence of the photochromic effect is generally also important.
• the samples are measured at two temperatures that at least cover the later control range. Include 80%. In the case of spectacle lenses for European markets, these are, for example, 10 ° C. and 35 ° C. If the fatigue of the photochromic reaction due to aging is important for the object according to the invention, the samples are subjected to artificial aging (for example 50 hours in a Suntest device from Fa . Heraeus) measured again.
• the following data are then taken from the spectral measurements - the longest wave excitation maximum in the UV (UV max ) from the spectrum in the unexposed state and the longest wave absorption value from the last spectrum at the end of the exposure, which generally corresponds to the fully activated state.
• maximum in the visible spectral range (VIS may ) The difference in optical density ( ⁇ OD) measured at VIS max with regard to the fully activated state compared to the unnoticed state is referred to as L max .
• the difference after 15 s exposure to the unexposed state is referred to as L e .
• the quotient of L e through L max is V e.
• the time Z a which the test body needs to lighten in VIS max from the fully darkened state in the optical density by the value L max / 2 is the decisive parameter
• the value Z a is given in seconds
• the photochromic dyes are then arranged in a table in a first column according to their VIS max value.
• the corresponding Z a values are entered in a second column and the V e values in a third column.
• the UV max values are listed in a fourth column.
• the temperature dependence T a can be entered in a fifth column and the aging value A can be entered in a sixth column
• photochromic dyes are used as the basic dye, the VIS max value of which is above 550 nm, ie. one or more substantially blue naphthopyran dyes as set forth below. Since the spectral perception of light of the human eye is greatest at this wavelength and its product with the standard illuminant D 65 at 620 nm essentially corresponds to that at 500 nm, the subjective impression of the photochromic reaction, i.e. Intensity of darkening, speed of darkening and brightening, etc., mainly characterized by these dyes. These and the remaining dyes are therefore divided into two groups.
• VIS max values above 620 nm and below 570 nm have proven to be unfavorable. In both cases the color correction is difficult, in the second case the permeability in the red spectral range is usually so high that color distortion occurs in extreme darkness, for example when skiing. Become two or more
• the mean values of their characteristic values (Z a , V e , T a , A) can be treated like the characteristic values of a single dye, provided their relative values do not differ by more than 15%. Otherwise, the further dyes to be added must be selected for each individual, appropriately selected basic dye, as shown below.
• the remaining, available photochromic dyes all those whose T a value deviates by more than 30% from that of the reference dye are deleted. If the resistance to aging is important, all those are deleted from the remaining ones whose A value deviates by more than 20% from that of the reference dye.
• UV_- ax value critical.
• the UV max values may not deviate from that of the reference dye by more than 15 nm.
• photochromic dyes from the group of benzopyrans and higher fused ring systems derived therefrom such as e.g. Naphthopyran dyes, which are readily available to a person skilled in the art, are reduced according to the preceding criteria - depending on the selected reference dye or base dye - the number of
• the neutral-colored, gray plastic object according to the invention further photochromic dyes to be mixed regularly to less than a dozen.
• the absorption spectrum of the reference dye in the fully activated state is then used to further narrow down the further photochromic dyes required to achieve a photochromic plastic object according to the invention.
• an ideal gray glass has a constant absorption over the entire visible spectral range from 380 to 780 nm.
• due to the spectral sensitivity of the human eye to light this is not necessary from a physiological point of view.
• the areas below 430 nm and above all above 680 nm are of minor importance.
• the wavelengths are determined in which there is a relative absorption minimum.
• the dyes with the corresponding VIS max - Values selected that are suitable to close this absorption gap If, according to the previous restrictions, the selection is too small to find an exactly matching dye, an appropriate dye mixture is used to fill such an absorption gap.
• the total concentration used is about 25 to 40% by weight of the reference dye. For most applications, e.g. B. for use as sun protection glasses in glasses, the concentration of the reference dye necessary for sufficient darkening is outside the scope of Lambert-Beer law.
• the photochromic compounds which can be used for the present invention all belong to the class of benzopyrans and higher, fused ring systems derived therefrom, such as, for. As naphthopyrans or fluorenopyrans.
• naphthopyrans or fluorenopyrans for the upper wavelength range there are mainly [2H] -naphtho (1, 2-b) -pyrans which are aromatic or heteroaromatic substituted in the 2,2-position, for the lower one
• Wavelength range in the 3.3 position correspondingly substituted [3H] -naphtho (2, 1-b) pyrans can be, for example, the naphthopyrans described in PCT-DE 98/02820 and the lndeno [2, 1-f] naphtho described in PCT / EP 99/05258 [1, 2-b] pyran derivatives and / or spiro-9-fluoro-no [1, 2-b] pyane derivatives. As preferred examples of this can be
• the shorter-wave absorbing photochromic dyes that can be combined with the base dye are, for example, 3- (4-diphenylaminophenyl) -3- (2-fluorophenyl) -3H-naphtho [2, 1-bpyran,
• oxazines or fulgides such as, for example, the oxazines described in US Pat. No. 5,753,146, without the Leave the essence of the present invention.
• Oxazine M max > 600 nm are sold by HCH James Robinson.
• small amounts of fulgides can be added, for example from the company Tokuyama are offered, their /. max value should exceed 570 nm.

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• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Eyeglasses (AREA)
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• 1999
  • 1999-11-16 WO PCT/EP1999/008791 patent/WO2000029877A1/de not_active Application Discontinuation
  • 1999-11-16 CA CA002318239A patent/CA2318239C/en not_active Expired - Fee Related
  • 1999-11-16 US US09/600,081 patent/US6373615B1/en not_active Expired - Lifetime
  • 1999-11-16 JP JP2000582826A patent/JP2002530686A/ja active Pending
  • 1999-11-16 EP EP99959280A patent/EP1047962A1/de not_active Withdrawn
  • 1999-11-16 AU AU16519/00A patent/AU750198B2/en not_active Ceased

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