Photochromic acetate plate, spectacle frame made from such a plate, spectacles and related manufacturing process

Abstract

Photoacetate plate (10), made with areas comprising at least one photochromic dye (4) and areas without photochromic dyes, arranged to define geometries, designs, patterns and images desired by the manufacturer, in which the areas comprising at least one photochromic dye (4) comprise a non-photochromic dye (6) with a light absorption profile such that absorption overlap between the activation region of the photochromic dye (4) and the absorption region of the non-photochromic dye (6) is avoided.

Description

[0001] PHOTOCHROMIC ACETATE PLATE, SPECTACLE FRAME MADE FROM SUCH A PLATE, SPECTACLES AND RELATED MANUFACTURING PROCESS

[0002] The present invention relates to a photochromic acetate plate, to a spectacle frame made from such a plate, to spectacles and to a related manufacturing process.

[0003] As is known, spectacle frames can be made from acetate, a material that is easy to process and therefore ideal for making spectacles, since it can be milled, polished and processed to create a wide diversity of fashionable frames with endless colour combinations. Acetate is a product derived from cellulose, which is an organic fibre. The starting material from which acetate is obtained is a plant-based cellulose.

[0004] In order to produce frames, cellulose acetate is transformed and processed into rigid plates. The acetate plates are then cut and milled to obtain spectacle frames in the desired shapes.

[0005] Photochromic acetates are known, which contain a photochromic dye which, in the presence of sunlight, reveals colours that would otherwise be invisible.

[0006] The effect is reversible, as when the material is protected from sunlight, the colour changes and returns to neutral, i.e. unactivated.

[0007] However, processes for manufacturing frames made from known types of photochromic acetate require the photochromic effect to be achieved in a totally uniform manner. Adding photochromic dye, which is dispersed in the material of which the frame is made, gives rise to uniform, single-colour colouring that is always different but not precisely defined and, above all, cannot be produced according to specific geometries, designs or images.

[0008] This means that with known processes, it is not possible to obtain acetate frames having a colouring featuring precise, desired and possibly even repeatable geometric patterns, designs, images or details.

[0009] There is a solution in which the frame is made using at least one photoacetate plate, the plate being made with areas comprising at least one photochromic dye and areas without photochromic dyes, arranged to define geometries, designs and images desired by the manufacturer.

[0010] However, the above solution has a drawback due to the fact that photochromic effects cannot be achieved throughout the entire volume of the frame, as the standard dyes used for acetate have an absorption spectrum such that the activation of the photochromic dye used is prevented.

[0011] The main purpose of the present invention is to produce a photochromic acetate plate and a spectacle frame made from this plate, which can present precise, desired and, if necessary, repeatable geometries, designs, patterns or images throughout the entire volume of the plate and thus of the frame itself, and which can be proposed in one or more different colours.

[0012] Within the context of this objective, one aim of the present invention is to produce a photochromic acetate plate (and a related spectacle frame) that can preferably be produced using the usual wet block or solvent block technology, while allowing the desired predetermined geometries, designs, patterns or images to be obtained. Alternatively, the photochromic acetate plate (and a related spectacle frame) can be produced by extrusion or using “dry block” technology.

[0013] Last but not least, the aim of the present invention is to produce a photochromic acetate plate, a spectacle frame made from this plate and a related process that are highly reliable, relatively simple to produce and of competitive cost.

[0014] This objective, as well as these and other aims that will become clearer hereinbelow, are achieved by a photoacetate plate, made with areas comprising at least one photochromic dye and areas without photochromic dyes, arranged to define geometries, designs, patterns and images desired by the manufacturer, characterized in that said areas comprising at least one photochromic dye comprise a dye with a light absorption profile such that absorption overlap between the activation region of the photochromic dye and the absorption region of the non-photochromic dye is avoided.

[0015] Further features and advantages of the invention will emerge more clearly from the description of a preferred, but not exclusive, embodiment of the spectacle frame and related process according to the present invention, illustrated by way of example and without limitation in the accompanying drawings, in which:

[0016] Figure 1 shows a schematic perspective view on the left of cubes without and with photochromic dyes and dye, in the presence of artificial light, and on the right the same cubes in the presence of sunlight, in accordance with the frame, spectacles and process according to the present invention;

[0017] Figure 2 shows a perspective view of a plate according to the present invention;

[0018] Figure 3 shows a spectacle frame made according to the present invention and exposed to artificial light;

[0019] Figure 4 shows a spectacle frame made according to the present invention and exposed to sunlight;

[0020] Figure 5 shows a graph of the absorption spectra of the dyes used in the plate, frame and spectacles according to the present invention.

[0021] With reference to the figures, the acetate plate according to the invention, generally indicated by reference number 10 (and therefore the spectacle frame according to the present invention, generally indicated by reference number 1), is made of photochromic acetate and the process for making it is, preferably, the solvent block process, also known as the wet block process. Alternatively, for example, the injection moulding technique can be used.

[0022] To obtain the acetate paste, the polymer, plasticizer and any additives are mixed in the presence of a solvent.

[0023] Using a calender, at least one photochromic dye 4 is then combined with the acetate paste to obtain photochromic acetate sheets. From the abovementioned sheets, at least one block (cube) 3 with photochromic dyes 4 is obtained.

[0024] The sheets can be cut using a dicer so as to obtain a plurality of photochromic cubes 3.

[0025] Similarly, an acetate paste is obtained without the addition of photochromic dyes.

[0026] From the abovementioned sheets, at least one block (cube) 2 without photochromic dyes is obtained.

[0027] In this case also, the sheets can be cut using a dicer to obtain acetate cubes 2 without dyes, or transparent cubes, but which can also be coloured with a non-photochromic dye 6 (acetate dye).

[0028] The non-photochromic dye 6 must be chosen appropriately so as not to have UV absorption.

[0029] This avoids absorption overlap between the activation region of the photochromic dyes and the absorption region of the non-photochromic dyes 6.

[0030] The non-photochromic dye 6 chosen with a well-defined light absorption profile allows the desired effect to be enabled throughout the volume of the frame and enables spectacles to be produced with all the pattems / geom etries already known in the acetate sector with the addition of the photochromic property.

[0031] Essentially, the acetate block is made with a combination of photochromic dye 4 and non-photochromic dye 6 (acetate dye), in which the light absorption spectrum of the non-photochromic dye 6 is such that acetate dye 6 does not absorb in the UV range (or absorbs significantly less than the photochromic dye 4) and therefore the acetate block can be coloured throughout its volume.

[0032] Therefore, the frame made with these acetate plates will have two different colours on passing from indoor lighting to sunlight.

[0033] Cubes 3 with photochromic dyes 4 and acetate dye 6 (non- photochromic) and cubes 2 without photochromic dyes (possibly with a dye that is not photochromic, i.e. acetate dye 6), in order to obtain the desired aesthetic result, are then transferred to a mould, appropriately combining the cubes 3 with photochromic dyes 4 and acetate dye 6 with the cubes without photochromic dyes in the desired configuration, in order to obtain a single block through pressure and temperature. The single block is then sliced and the slices are left to dry in an oven.

[0034] The photochromic dyes 4 are not dispersed homogeneously in the acetate material from which the frame is made, but are organized or arranged in such a way as to highlight specific geometries, designs, patterns and images.

[0035] The spectacle frame is thus made of photochromic acetate, in which the photochromic dyes 4 and the acetate dye 6 are arranged according to a specific aesthetic choice, desired by the manufacturer, to create appropriate patterns, including, for example, the one known as “tortoiseshell”.

[0036] The presence of acetate dyes 6 combined with photochromic dyes 4, in which the former are chosen so as not to interfere with the absorption of the photochromic dyes 4, enables the entire volume of the frame to be coloured in the absence of sunlight, so that in indoor light the frame will have a colour throughout its volume, while in sunlight the frame will have a colour given by the activation of the photochromic dyes 4.

[0037] The invention also relates to a spectacle frame made with the plate described above, and also to a pair of spectacles.

[0038] In practice, it has been found that the photoacetate plate, the spectacle frame, the spectacles and the process according to the invention entirely fulfil the objective and the set aims, as it is possible to obtain a plate and thus a frame with geometric patterns, designs and the like throughout the volume of the plate (and the frame), made with photochromic dyes and acetate dye, arranged in an appropriately defined manner in the acetate plate from which the frame is made. The plate, the frame, the spectacles and the process thus conceived are subject to numerous modifications and variations, all of which fall within the scope of the attached claims.

[0039] Furthermore, all the details may be replaced with other technically equivalent elements.

[0040] In practice, the materials used, and also the contingent dimensions and shapes, may be any depending on the requirements and the state of the art.

[0041] The content of Italian patent application No. 102024000029349, the priority of which is claimed in the present patent application, is incorporated by reference.

[0042] Where the technical characteristics in the claims are followed by numerical references and / or abbreviations, these numerical references and / or abbreviations have been added for the sole purpose of increasing the intelligibility of the claims and consequently these numerical references and / or abbreviations have no effect on the scope of each element identified only for indicative purposes by these numerical references and / or abbreviations.

Claims

CLAIMS1. Photoacetate plate (10), made with areas comprising at least one photochromic dye (4) and areas without photochromic dyes, arranged to define geometries, designs, patterns and images desired by the manufacturer, characterized in that said areas comprising at least one photochromic dye (4) comprise a non-photochromic dye (6) with a light absorption profile such that absorption overlap between the activation region of the photochromic dye (4) and the absorption region of the non-photochromic dye (6) is avoided.

2. Plate according to Claim 1, characterized in that said non- photochromic dye (6) does not absorb in the UV range or absorbs to an extent that is not significant compared to the photochromic dye (4).

3. Spectacle frame (1) made from at least one photoacetate plate (10), said photoacetate plate being made with areas comprising at least one photochromic dye (4) and areas without photochromic dyes, arranged to define geometries, designs, patterns and images desired by the manufacturer, characterized in that said areas comprising at least one photochromic dye (4) comprise a non-photochromic dye (6) with a light absorption profile such that absorption overlap between the activation region of the photochromic dye (4) and the absorption region of the non-photochromic dye (6) is avoided.

4. Frame according to Claim 3, characterized in that said non- photochromic dye (6) does not absorb in the UV range or absorbs to an extent that is not significant compared to the photochromic dye (4).

5. Spectacle frame according to Claim 3, characterized in that said areas with photochromic dye (4) and said areas without photochromic dye (6) are obtained by means of photochromic acetate cubes (3) and non- photochromic acetate cubes (2) arranged according to a desired aesthetic choice.

6. Process for making spectacle frames, comprising the steps consisting in: treating an acetate paste;adding at least one photochromic dye (4) to said acetate paste to obtain photochromic acetate sheets; treating an acetate paste free of photochromic dyes and containing colours chosen to achieve a desired aesthetic result, to obtain acetate sheets free of photochromic dyes; from said acetate sheets with at least one photochromic dye (4) and one non-photochromic dye (6) and sheets with non-photochromic dye but without photochromic dye (4), obtaining at least one block (3) of acetate with photochromic dye (4) and non-photochromic dye (6) and at least one block (2) of acetate without photochromic dye; placing said block (3) of photochromic acetate with photochromic dye (4) and said block (2) of acetate without photochromic dye in a mould so as to define the desired geometries, designs, patterns and images; applying pressure and temperature to said mould to obtain a single block; slicing said single block and allowing the slices thus obtained to dry in an oven; obtaining spectacle frames of desired shapes from said dried slices.

7. Process according to Claim 6, also comprising the steps consisting in: using a dicer, cutting said photochromic acetate sheets with photochromic dye and producing a plurality of said cubes (3) of photochromic acetate with photochromic dye (4); using said dicer, cutting said acetate sheets without photochromic dye to obtain a plurality of said cubes (2) of acetate without photochromic dye.

8. Process according to Claim 7, characterized in that it comprises a step consisting in combining more than one block (2) without photochromic dye with a block (3) with photochromic dye (4).

9. Process according to Claim 7, characterized in that it comprises astep consisting in combining more than one block (2) without photochromic dye with more than one block (3) with photochromic dye (4).

10. Process according to Claim 6, characterized in that said block (2) without photochromic dye is made with non-photochromic dyes (6).

11. Spectacles, comprising a frame and a pair of arms, said frame and said arms being obtained from a photoacetate plate (10), made with areas comprising at least one photochromic dye (4) and areas without photochromic dyes, arranged to define, geometries, designs, patterns and images desired by the manufacturer, characterized in that said areas comprising at least one photochromic dye (4) comprise a non-photochromic dye (6) with a light absorption profile such that absorption overlap between the activation region of the photochromic dye (4) and the absorption region of the non- photochromic dye (6) is avoided.

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