DE4422663A1 - Photochromically (phototropically) dyed transparent article - Google Patents

Abstract

A photochromically dyed transparent article is described, which additionally has an absorbing substance which at least partly absorbs light in the UV spectrum and, if necessary, of a wavelength below a specific wavelength range in the visible spectrum. The invention is distinguished by the fact that the absorbing substance is provided in a layer which is provided on and/or below that surface of the article which faces away from the direction of light incidence.

Description

The invention relates to a photochromic colored transparent object, which also has a has absorbent substance that is tight in UV-Be rich and possibly light with a wavelength below a certain wavelength range in visible area at least partially absorbed.

Often it is necessary that optical parts, such as Lenses, eyeglass lenses and in particular sun protection lenses  water, visors of helmets etc. impermeable to UV and especially for UV-A radiation. At glasses glasses Furthermore, it is often used for physiological reasons required that they be at least partially short-wave Radiation in the visible range, for example light with a wavelength less than approx. 400 nm absorption ren.

In the case of plastic parts which (on the light side) are superficial are colored photochromic, as shown for example in U.S. Patent 4,286,957 or DE-A-35 16 568 can, according to the physiological requirements absorbent substances or substances, such as. B. UV Absorber, added to the polymer during manufacture become. This can be done, for example, by adding it to the Monomer before polymerization or in the batch before extrusion. Unless the photochromic coloring does not reach very deep into the polymer Performance, d. H. especially the darkening of the light sided photochromic coloring by adding from sorbent substances hardly weakened.

It is different with plastic parts, however are colored photochromically in the mass. With these in the Mass absorbed by photochromically colored plastic parts the additive is just the UV-A radiation that is used for Excitation of the photochromic molecules is needed. The Performance, d. H. the degree of darkening is therefore in in this case drastically due to the absorbent additive decreased.

The invention has for its object a photo chrome colored transparent object, which too additionally (at least) an absorbent substance  points, the light in the UV range and, if necessary Light with a wavelength below a certain Wavelength range in the visible range at least partially absorbed, so that the photochromic performance especially from in bulk colored objects by the absorbent sub punch is not affected.

An inventive solution to this problem is in Claim 1 specified. Further training of the Erfin are subject of the subclaims.

According to the invention, the absorbent substance is in one Layer provided on and / or below the Surface of the counter facing away from the direction of light stands is provided. The absorbent can Substance one or more UV absorbers or the phy Connections corresponding to biological requirements include those in the normally facing away from the light Introduced side of the item or on this side be applied.

It can also include certain substances in the item introduced and other substances on the object for example, who applied by means of a layer of lacquer the.

Depending on the plastic material of the counterpart stand, you can use the most varied of methods Production of the absorbent layer used who the. In any case, the photochromic counter is first was made and then in the light surface of the object facing away from the direction of fall the absorber introduced or applied to it:  

With thermosets, such as acrylates, CR 39 or MR-6 can for example those in US Pat. No. 4,286,957 or DE-A- 35 16 568 described methods used analogously be, of course, instead of a photochromic Dye or UV absorbers are introduced.

When the absorber is introduced into a lacquer, it can by spraying, brushing or using the spin technique be brought.

Thermoplastics such as polycarbonate can be introduced a procedure analogous to the absorbent substances are used, as in DE-A-42 35 182 be is written.

The procedure according to the invention is particularly suitable ders for mass-colored objects and especially for Eyeglass lenses.

The following is the production of photochromic art Described fabric parts using an exemplary embodiment ben:

In a monomer, for example the TS-150 monomer Tokuyama Corp., 500 ppm of the photochromic Dyes stirred in at 20-25 ° C within 2 h. After adding 1% initiator (tert. Butyl peroxyneode canoat) is stirred for a further 15 min at 20-25 ° C and the The mixture was then degassed at 10 torr.

The mixture is poured into the casting through a 1.2 µm filter mold (2 mm face glasses) filled and according to a temperature program recommended by the monomer manufacturer  Cured for 20 h at 35-90 ° C. After demoulding the glasses are annealed at 120 ° C for 2 h.

This is followed by the introduction of the UV Protection, which is described below:

In 1 liter of softened water, in which a teaspoon of house maintenance detergent is given, 40 g 2.2 ', 4.4'- tetrahydroxybenzophenone suspended and by heating brought to 95 ° C in solution. In this solution the - Prepared accordingly - glasses dipped for 45 min and by rinsing in hot water at 80 ° C for 15 seconds (Add 1 dash of household detergent) cleaned.

Variant A without pretreatment (UV protection on both sides
Variant B back surface covered (UV protection on the front
Variant C front surface covered (UV protection on the back

The measurement results are presented below:

The photochromically colored glasses were measured in a measuring arrangement in accordance with DIN 58 217, ie irradiated with 50 klux at 23 ° C. for 15 min. The photo chrome power was determined, ie the difference in transmission Eτ in the unexposed and exposed state after 15 min. The transmissions are assessed according to the spectral sensitivity of the normal observer V _λ .

The same measurement was made with the different ones repeated versions of UV-protected glasses. Of the UV protection achieved is very good in all 3 variants, for variants B and C within the measurement accuracy table (τ at 390 nm <1%).  

This gives the following results:

If a so-called "blue blocker" is used instead of the UV absorber used (for example 20 g BASF Celliton yellow G and BASF Celliton Yellow 7 GFL per liter of water, diving time 10 min), none of the photochromic dyes show more a light reaction in variants A and B. In variant C is only slightly weakened, the Re. caused by the yellow pre-coloring reduction in transmission in the unexposed state is caused.

Claims (7)

1. Photochromic colored transparent object, which additionally has an absorbing substance that absorbs light in the UV range and optionally with a wavelength below a certain wavelength range in the visible range at least partially, characterized in that the absorbing substance is provided in one layer , which is provided on and / or below the surface of the object facing away from the direction of light incidence. 2. The article of claim 1, characterized in that the object from a Plastic material is made. 3. Article according to claim 2, characterized in that the object with photo chrome dye is mass-colored. 4. Object according to one of claims 1 to 3, characterized in that the object is a pair of glasses glass is. 5. Object according to one of claims 1 to 4, characterized in that the absorbent substance several different UV and / or light visible its area has absorbent substances which give if necessary arranged in different layers are.   6. Process for the manufacture of an object one of claims 1 to 5, characterized in that first the photochromic Item produced and then in the Surface of the counter facing away from the direction of light state of the absorber by means of diffusion from the light facing surface is brought forth. 7. Method of making an item according to one of claims 1 to 5 or according to claim 6, characterized in that first the photochromic Item manufactured and then on the Surface of the counter facing away from the direction of light a layer with the absorber is applied.