DEP0001148BA - Process for treating glass surfaces to reduce the amount of reflected light - Google Patents

Description

Patent attorneys
Dlpl .-! Ng. F. Sailor
DipL-lng. E. Vorwerk

Berlin SW 68 §8

Hedemannstrasse * 10

Hedemannstrasse 10,

Pilkington Brothers Limited, Liverpool 2 / England, (County 27728, Martins Bank Building, Water Btreet Lancaster)

Process for treating glass surfaces for reduction

des · ν *! Β · ~ * αίΒ & Βαι · ±. Mts of reflected light <

The invention relates to the treatment of the surface of glass to reduce the amount of light reflected from the surface at all incident light "One purpose of the invention is to provide an improved treatment that is simple and can be used cheaply on large glass surfaces, the treatment being precisely controllable and a uniform result over the entire treated surface results in «

The process for treating glass surfaces in order to reduce the amount of light reflected from the surface incident light according to the invention / in that the surface repeatedly with a solution of Silifeefitetrachlorid in a volatile, non-aqueous solvent is wetted that every layer of atmosphere created in this way on the glass exposed until dry and that each dried layer is rubbed off until it shines,

Any dried layer is dull and the rubbing must be continued until the dullness disappears entirely and the surface is completely shiny and prepared for the next wetting »

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A suitable solvent for Silifeesrfcetrachlorid is

Carbon tetrachloride, a strength of 1 % for weight

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silicon tetrachloride has been found to be sufficient.

Weaker solutions can be used, but a larger number of wetting and rubbing processes are then required. Stronger solutions can be used, they are

cium , ο but difficult to use. In place of Silil & e * rt; etrachlorid

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Siliteeschloroform or Silicate tetrabromide can be used »The solution of the bromide mixture can be more concentrated.

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The wetting of the glass surface is preferably carried out by

Dipping the glass over the high edge into the solution so that both surfaces are wetted at the same time »

The atmospheric conditions to which the wetted surface is exposed should correspond to those in the place on which the treatment is carried out »

The number of wetting and drying operations required to achieve the best result will vary. You depends on the composition of the glass to be treated, the strength of the solution and the atmospheric Conditions. However, there is one most favorable number; a porting of treatment after this number causes the reflectivity the surface increases instead of decreasing »When the glass surface is successively wetted and dried its matte color changes and it has been found that ordinary window glass gives the best result becomes when the color turns purple.

To explain the 'invention, an embodiment is described below in which the method is based on commercial

IcLtQXMdL common window glass with a content of about 72 % silicon /

and is applied with a refractive index of approximately 1.52.

When carrying out the process, the glass to be treated is first cleaned and brought to the surrounding temperature,

After the glass is cleaned and has reached the air temperature at which the treatment is carried out, it will

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dipped over the high edge in a solution of silicon tetrachloride in carbon tetrachloride ι the strength of the solution is around 1 % for the unit volume of the tetrachloride.

The glass is in the. Solution immersed and immediately withdrawn without pause, it is then exposed to the air, until the surface is dry. The surface is then rubbed until it becomes shiny. »The surface sometimes has a dull appearance. This dullness is completely eliminated by rubbing the surface with a cloth. Sometimes the surface has a greasy appearance. In this case, intensive rubbing is required because it is completely clean and shiny must be before the glass is immersed again.

If the surface is completely clean and shiny, then the glass is immersed again in the solution and immediately pulled out again, whereupon it is then again air-dried. After the surface has dried the second time rub it down with a cloth again until it is clean and shiny. The successive steps, viz Dipping, drying and rubbing are repeated until the reflectivity of the surface reaches its lowest value has.

After the third immersion of the surface of the glass, it gets a brownish color. With further immersion the color deepens and changes to purple. Usually

the color has turned completely purple after seven or eight times / lintaueheη. This color indicates that the cheapest Conditions, namely the condition of smallest reflectivity Sj is reached.

If the treatment is continued after the color has changed to purple, the reflectivity increases steadily. the Color changes first to blue, then blue-green and yellow-green «

The treatment described can halve the amount of light reflected by the untreated window glass be decreased. The amount of light reflected from each treated surface of the window glass is around 2% "

The rubbing of the glass between successive dips is very important, otherwise the smooth would be Surface of the glass can be completely destroyed »

After the last immersion, the surface is rubbed until it becomes shiny and then washed off, e.g. with a barrel or alcohol.

When it comes to lead glasses with a content of up to 65 % PbO and about 30% Sii with a refractive index of 1.7, a very high reduction in reflection is achieved, the amount of light reflected from each surface is around 1 %, In general, lead glasses require fewer treatments than commercial "window glass"; only 6 dips are required for lead glass compared to eight for window glass.

For lead glass, the most favorable color is a deep bronze purple red.

It is noted that the method of reducing the reflectivity of the glass surface by immersion in a Solution according to the invention is therefore particularly advantageous,

because a relatively large glass surface can be treated easily and economically.

The present invention also resides in a method of accelerating the formation of driers. Layers under conditions normal humidity, after which a volatile substance that easily mixes with the treatment liquid is added to it being, with the moisture that is necessary to the

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To produce the desired reaction with the silicon tar tetrachloride or silicon chloroform or oil tetrabromide, it is quicker Layer is made available.

For this purpose, a ketone, e.g. methyl-ethyl-ketone, preferably acetone, can be added to the solution, if small Quantities are used; the action of the ketone is that of a reservoir with very small amounts of moisture on the glass surface become available to initiate or support the development of the layers.

Experiments have shown that the formation of layers is accelerated by adding an amount of acetone of 2% for the unit volume of the carbon tetrachloride and that even better results are obtained if the acetone content is 3 "to 5 % for the unit volume of the tetrachloride used. Care must be taken, however, to avoid further increasing the percentage used, as tests have shown that a large percentage of acetone causes the glass to become cloudy and that at around 10% the effect of the solution is completely prevented.

In a very dry atmosphere, the addition of acetone shows a remarkable increase in the rate of formation the shift. Excellent results over a wide range of moisture are achieved through the use of a treatment solution.

Solution achieved according to the following / rml '/:

Carbon tetrachloride 100 parts (for the unit of volume, J.

Acetone 3 parts,

Sili- @ ^ »tetrachloride 1 to 2 parts.

The use of acetone is not only a means of accelerating the layer formation, but _s as stated, the number of dips can be reduced compared to a method in which acetone is not used. Excellent results have been achieved by using only six dips to treat the glass, while without acetone it would take seven to eight.

From another point of view, it is noted that the invention can be described as a method of increasing the proportion of incident light passing through the glass surface by forming a surface layer on the glass by wetting the surface with a solution of silicon tetrachloride in carbon tetrachloride to which a small amount (up to 5 %) of acetone is added to the solution by exposing the layer to the atmosphere and rubbing the layer after drying until it is shiny and by repeating the treatment until a purple color is noticeable in the layer is"

Sin advantage of the invention that lies in its application

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on glasses with a low silicon content is that these glasses, in general, lead to a decomposition of the surface in a humid atmosphere tend to have an increased resistance to this, if they according to the invention with a layer.

The invention relates not only to the method described

ren to reduce the amount of incident reflected light and to increase the amount of that transmitted by the glass Light j but also the product treated in this way.

Claims (1)

Claims ι 1 * Process for coating a glass surface to reduce the amount of light reflected from the surface, marked by repeatedly wetting the surface with a solution of Sili - @ = @@ tetrachloride in a volatile, non-aqueous solution Solvent, by exposing each created layer to the atmosphere "until the layer dries, and through rubbing down "every dried layer until it is shiny" 2. The method according to claim 1, characterized in that the glass surface with a solution of SiIic ^ chloroform or iuiK Silicestetrabromide is wetted in a volatile, non-aqueous solvent » als 3 «method according to claim 1, wherein« fei * · wetting solution ium
a / solution of silica tetrachloride in carbon tetrachloride verarenctei zfirett rid bht, / in a strength of 1 % ' ium of silicon tetrachloride. 4. The method according to any one of the preceding claims, characterized by the addition of a small amount of a volatile Ketones to the wetting solution, which makes the generation of the ivLM the desired reaction with the silicon reagent required moisture for the layer on the surface of the glass quickly is made available. eiurcli 5. The method according to claim 4, characterized in that d [ use of / [the The wetting solution 7 contains up to 5% acetone. 6. Process for treating glass surfaces to reduce the proportion of incident that is reflected from the glass surface Light and to increase the proportion of the incident light transmitted by the glass, consisting in the formation of a Surface layer on the glass by wetting the surface with a solution of silicate tetrachloride in carbon tetrachloride, the strength of the solution being 1 % - of the silicon tetrachloride and mixed with 3% acetone, exposing this layer to the atmosphere and rubbing the dried layer until it is glossy and repeating the treatment until a purple color appears in the layer Layer is noticeable. OZ, 7 «Commercial window glass with about 72% Si and with a refractive index of around 1.52, characterized in that, each surface is covered with a layer according to claim 1 and each covered surface of the glass has a purple-red color when viewed at an obtuse angle to the surface, and that the amount of the incident light reflected from each covered surface is approximately 2 % . 8. Lead glass in plate or sheet form with a sigehalt of around 30 % and a refractive index of approximately 1.7> characterized in that "each surface is covered with a layer according to claim 1 and each covered surface of the glass shows a rich bronze-purple color when viewed at an obtuse angle to the surface and that the amount of incident light reflected from each covered surface is approximately 1 % . 9 «Method for treating glasses according to one of claims 1 to 6 f * j Γ ^ ΤΊ " " \ 7 OYI ^ f ⁵ T * Ql ^ P ¹ T ^1- PT ΓΊ f ^ lr in ) A inu Sa Gr * ^ S ^ fiff rPfiJ *! & 3j T * tj "1 GX ^{1 -} Jj ^ T "! Τι * Ί C ^ I'll i * I fi Pi ΊΊ Tl rj f7"QT> * ΐ ο * characterized in that the glass over the high edge into a solution of the silicon reagent / in carbon tetrachloride is dived "