DD276084A1 - TEMPORARY PROTECTIVE LAYER FOR OPTICAL GLASSES AGAINST CORROSION AND SEALING - Google Patents

Abstract

The field of application of the invention relates to the protection of fabricated or semi-finished optical Praezisionsflaechen against corrosion and fogging and other schaedigende influences during processing, storage and intermediate storage in the production process of optical components. The invention has for its object to achieve within the scope of known optical technology, a temporary protection of Praezisionsflaechen particularly endangered glass so as to achieve an increase in the yield and reduction of reworking costs. According to the invention a temporary protective layer is applied, which consists of soluble in toluene or halogenated hydrocarbons, film-forming, aryl-substituted polyarylenevinylenes, z. As poly (1,4-phenylene-1-phenylvinylen) exists. This coating can be applied in the context of conventional optical technology without special technological effort and can be removed at any time without any ado without adverse effects for subsequent processing steps (surface trimming, fine kitten).

Description

For this 1 page formulas

Field of application of the invention

The invention relates to a temporary protective layer for optical glasses against corrosion and fogging, which are used for optical precision surfaces during the processing process, during temporary storage in technologically conditioned processing breaks and in the storage of saturated optical components up to their (linsatz for the completion of optical components in wlif .enscruiftlichen device construction can be applied.

Characteristic of the known state of the art

Made in the machining process optical precision surfaces are protected after the polishing process or before further processing steps against corrosion, contamination and mechanical damage. Previously used protective layers are made of polyvinyl alcohols, polyacetates or other polyesters, to which other resins can also be added. The coating is applied by brushing, dipping, spraying and pouring. The protection thus achieved is not sufficient for glasses susceptible to corrosion, since in particular the moisture of the air infiltrates or penetrates the protective layers and triggers the corrosion process. As a result of longer storage tents and the effect of high humidity, these so insufficiently protected precision surfaces of optical components must be re-processed (rework), and then finally to be used in optical components can. Another protective option known in the literature is to render the polished surface hydrophobic (GB 1201275, USA 4410563). The addition of silanes to the Glasoborfläche should cause this effect. Since this deposition occurs in the regol at discrete points on the surface and no composite film forms, the coating is removed by hydrolytic cleavage under the action of moisture. The Hydrphoblerung is also a massive chemical attack on the glass surface often with the participation of water, alcohol and alkanoic acids, so that this process leads to the destruction of the optical quality of the surfaces in special corrosion endangered glasses.

A good protective layer, which ensures as far as possible a sufficient corrosion protection, can be achieved by applying metal layers (Kailer, A .: Forschungsbericht CZ 1961, Kalier, A., Pauli, M., Junhold, H.-J .: Forschungsbericht CZ1964). , The coating is realized here in a physical-chemical way. The disadvantage of the metal layer is that with it a check of the shape deviation or surface quality U with conventional methods is no longer possible. Such layers must be removed chemically or abrasive. This results in the best case, the same effort as "I Correction of corroded areas.

Another way of protecting particularly endangered glasses against corrosion is currently the storage and transport of such glasses. In special containers that are hermetically sealed against atmospheric moisture (30% relative humidity).

As a protective layer against corrosion and fog, the application of a layer of purified paraffin has been proposed (WP: DD 245652 A1). As a result, a complete protective effect can also be achieved. The disadvantage of this variant is that this can not be done in conjunction with conventional Rohklebekittsn, the paraffin layer is attacked in hydrocarbon-containing atmosphere and media and dissolved and for the coating, a modification of the conventional technology is necessary.

Object of the invention

The aim of the present invention is to develop a usable between the processing steps protective layer for finished or semi-finished precision optical surfaces, which protects against corrosion, fogging, dirt or transport damage and residue pilot without affecting the optical quality and consequences for the further treatment of precision surfaces (metallization , Antireflection coating, etc.). The invention is directed in particular at the protection of the shortcomings of the previous methods in Langzoif and to overcome their application to particularly corrosion endangered glasses in the machining process. The use of the invention should be realized within existing optical technologies without additional effort and oine cause significant increase in Gutauebeute processed optical components.

Explanation of the essence of the invention

The invention has for its object to achieve in the context of conventional optical technologies with the processing stages grinding, polishing, centering, surface treatment during the processing steps and topologically related storage periods away a temporary protection of precision surfaces particularly vulnerable optical glasses against corrosion, fogging and other harmful influences. According to the invention, this object is achieved in that a layer is applied, which is soluble in organic solvents and solvent mixtures, film-forming, aryl-substituted Polyarvlenvinylonen of the general formula. 1

- Ar - G = C -

I i

R ₁ R ₂

Ar is an aromatic radical from which two bonds originate and which is preferably derived from benzene,

Biphenyl, diphenyl ether and diphenylmethane. R and R ₂ are substituents: R _{1 is} phenyl and substituted phenyl, preferably 4-methylphonyl, 4-chlorophenyl, 4-methoxyphenyl R] - phenyl and substituted pheny., Preferably 4-methylphenyl, 4-chlorophenyl, 4-methoxyphenyl and hydrogen. As for the temporary protective layers according to the invention are particularly suitable aryl-substituted polyarylenevinylenes

called (formulas 2-7):

Poly (1,4-phenylene-1-phenylvinylene) 2 Poly-1,4-phenylene-1 (4-methylphenyl) vinylene) 3 Poly [1,4-phenylene-i (4-chlorophenyl) vinyl] 4 Poly (1,4-phenylene-1,2-diphenylvinylene) 5 Poly (1,4-phenylene-1,2 bis (4-methoxyphenyl) vinylene) β Poly (oxy-1,4-phenylene-1,2-diphonylvinyl-1,4-phenylene) 7

Solutions of aryl-substituted polyarylonyl nylonone in organic solvents (preferably toluene or halogenated hydrocarbons, preferably toluene, chlorobenzene or xylene) form surprising catfish such moisture-impermeable and dense films on solid surfaces that meet the objective of the present invention.

The solvent should be selected so that a closed layer formation and no attack of the surface takes place. When operating at room temperature, the boiling point of the solvent should be between 100 ° C and 200 ° C (preferably toluene, chlorobenzene, xylene). The formation of dense layers takes place particularly favorably when polyarylenevinylenes with number-average relative molecular masses Mn 5000 are used. The coating can be achieved favorably by application (brushing, spraying or dipping with a solution containing 1-20 mol% aryl-substituted polyarylenevinylene.) To increase the contrast in the optical quality test, the protective layer can be dyed dark by introducing organic dyes into the solution Softeners, stabilizers and binders can be added to improve the coating properties.The protective layer of polyarylenevinylenes can also be used in conjunction with organic under- and outer layers (lacquers, green adhesive, fine cements) and inorganic under- and outer layers (antireflection coatings, metal layers).

The fluorescence of the Polyarylenvlnylenschlcht In the UV can be used to control the hole-freedom during coating and to control the residue-free removal of the layer low. The Polyarylenvinylenlösung can be handled well in Fertigungsprczeß because it shows no signs of aging by the action of atmospheric oxygen or moisture and at any time can be diluted to a suitable concentration.

In the manufacture of optical components with several precision surfaces (lenses or prisms), the already finely polished surface can be covered with the protective layer and then held for processing further surfaces with raw adhesive. This prevents the attack of the aqueous cooling and Spühlmediums as the Rohklebekittes itself to the already manufactured precision surface of sensitive glasses. If necessary, the protective layer of polyarylenevinylene can be removed without residue in the abovementioned solvents (aromatic hydrocarbons, halohydrocarbons) without negative effects being incurred for subsequent treatments (surface area coating).

Depending on the technological requirements of the overall optical component manufacturing process, it may be possible, and may be convenient, to use a different solvent than that used for film formation (e.g., perchlorethylene, trichlorethylene, methylene chloride) for stripping.

The layer has the effect of protecting optical surfaces of endangered glasses (acid class β 1, weathering class 1), in particular against corrosion and fogging, as well as against mechanical influences, ng, by transport movements (scratches) and atmospheric contaminants (dust, splashes, atmospheric moisture).

Ausführungsbelsplele example 1 Three cylindrical bodies made of optical glass LaK 73 (acid class 3, weathering class 3 according to glass catalog JGW) are on a Circular surface of about 1 cm ¹ size polished to optical quality. The quality of the surface is in the incident light microscope

controlled. After cleaning with acetone and quality control, a 5% toluene solution of

Poly (1,4-phenylene-1-phenylvinylene): Ar "phenylene, Ri = phenyl, R _: = hydrogen, M _n = 14300

applied by brush.

After drying the layer and checking for no holes, the cylinder bodies treated in this way are tested for testing Corrosion resistance 3 days exposed to a saturated steam atmosphere at 50 ± 5 ⁰ C. The examination of the optical quality in the incident light microscope after removal of the protective layer resulted in the treated A complete protection against corrosive water attack. An unprotected parallel examined Surface and a not according to the invention coated with polyvinyl acetate showed dagegr η as a result of Water vapor attacks clearly corrosive phenomena l.i Form of efflorescence and recognizable by interference Corrosion stains. Example 2-4 LaK 73 surfaces prepared analogously to Example 1 are coated with the polyarylene vinylenes 3 and 7 and after the Corrosion test evaluated analogously to Example 1. The result is summarized in the following table: Ar R, R ₂ M _n result Benzene 4-methylphenyl hydrogen 14600 no corrosion Diphenyl ether phenyl-phenyl-20000 no corrosion Diphenyl ether phenyl phenyl-6500 no corrosion Example 5 LaK 73 surfaces prepared analogously to Example 1 were coated as in Example 1 and over 3 months in the Production hall stored. The optical quality test after removal of the protective layer revealed no change from freshly polished Surfaces. A comparable untreated probo clearly showed corrosion spots and fogging, which could be caused by cleaning in Do not remove acetone.

Example β

Purified and polished LaK 73 glass is analogous to Example 1 with poly (1,4-phenylene-1-phenylvinylene) by Aufstrelchen

of a 5% solution in purified chlorobenzene.

The 5% solution of chlorobonzole was added to color 0.01% crystal violet picrate. It became a dark green layer

erhalton. After storage in a saturated steam atmosphere (3 days at 50 ± 5 * 0 and the removal of the layer could be detected in a light microscope no corrosion phenomena.

CH ₃

il

Cl

= CH-

ff ^ c =

H ₃ CO PCH ₃

J76 08H

 n

Claims (7)

1. Temporary protective layer for optical glasses against corrosion and fogging, characterized in that this layer of soluble in organic solvents and solvent mixtures, film-forming, arylsubstituierlen polyarylenevinylenes of the general formula 1 R ₁ R ₂ where Ar is an aromatic radical from which two bonds originate and which is preferably derived from benzene, biphenyl, diphenyl ether and diphenylmethane: R ₁ = phenyl and substituted phenyl, preferably 4-methylphenyl, 4-chlorophenyl, 4- Methoxyphenyl, R ₂ = - phenyl and substituted phenyl, preferably 4-methylphenyl, 4-chlorophenyl, 4-methoxyphenyl and hydrogen. 2. Temporary protective layer according to claim 1, characterized in that aryl-substituted polyarylenevinylenes are dissolved in purified toluene, halogenated hydrocarbons or mixtures thereof and applied by brushing, spraying or dipping onto the cleaned and dry polished precision optical surface. 3. Temporary protective layer according to claim 1 and 2, characterized in that aryl-substituted polyarylenevinylenes of number average molecular weight M _n = 5000 are used. 4. Temporary protective layer according to claim 1 and 2, characterized in that the layer for increasing the contrast in the optical quality control contains organic dyes. 5. temporary protective layer according to claim 1,2 and 4, characterized in that plasticizers, stabilizers and binders are incorporated to improve the mechanical properties. 6. Temporary protective layer according to claim 1, 2, 4 and 5, characterized in that the layer is combined with further top and bottom layers. 7. temporary protective layer according to claim 1,2 and 3, characterized in that the protective layer by brushing, spraying a solution or immersion in a solution of poly (1,4-phenylene-1-phenylvinylen) of concentration 1-20 Ma. % is produced in toluene on the glass surface.