DE3206775A1 - NEW POLYMERS AND THEIR USE FOR THE PRODUCTION OF OPTICAL ELEMENTS - Google Patents

Description

New polymers and their use in the manufacture of optical elements.

The invention relates to new polymers and their use for the production of optical elements.

It is generally known to produce optical elements, for example lenses, prisms and light guides, from polymers. In order to be suitable for the production of optical elements, the polymers must be colorless and transparent. Further it is desirable that the polymers have a high index of refraction. In the case of lenses, it makes use of High refractive index materials make it possible to use thinner lenses that have the same focal length as thicker lenses made from lower refractive index materials. The use of thinner lenses diminishes the volume of space required by the lens within an optical device or device. In addition, the production of thinner lenses requires less material, which has a favorable effect on the cost factor.

It has also been shown that materials with high Refractive index are advantageous for the manufacture of light guides. From US Pat. No. 3,809,686 there is a method of manufacture of light guides by selective irradiation of polymethyl methacrylate known with ultraviolet light of certain wavelengths. The selective irradiation leads to a recognizable Increase in the refractive index of the polymer along the path of the focused radiation. The refractive index of polymethyl methacrylate however, is only 1.49 to 1.50, and the increase caused by the irradiation is comparative small amount. (The change in the refractive index achieved is 0.5 10 E, where E is the exposure in joules per

Square centimeters of ultraviolet light from a mercury arc is).

The use of polymers with a considerably higher refractive index (above 1.60) in optical components would make it possible to use considerably thinner optical components than has previously been the case. This means that a There is a need for transparent and colorless polymers of high refractive index which can be used in the manufacture of optical Have components used.

The invention was based on the knowledge that such polymers can be produced with a high refractive index, if they are made from new monomers of the following structure:

R ³ OR ²
CH ₂ = CCS-CH-Ar-R ¹

where mean:

Ar is an arylene radical, preferably having 6 to 22 carbon atoms, e.g. B. a phenylene, naphthylene, anthrylene, perylenylene or acenaphthenylene radical.

R is a hydrogen or halogen atom, for example a Chlorine or bromine atom or an alkyl radical, preferably with 1 to 20 carbon atoms, for example a methyl, Ethyl, isopropyl or hexyl radical or an alkoxy radical, preferably having 1 to 20 carbon atoms, e.g. B. a Methoxy or ethoxy radical or an amino radical or a sulfide, sulfoxide or sulfonate radical or an aryl radical, preferably having 6 to 18 carbon atoms, e.g. B. a phenyl radical or a heterocyclic radical, preferably

a 5 to 7-membered ring that can be saturated,
for example a pyrrolidinyl, morpholinyl, piperidinyl, tetrahydrofuryl, dioxanyl or quinaldinyl radical or an unsaturated ring, for example a pyrrolyl, isoxazolyl, imidazolyl, isothiazolyl, furazanyl or pyrazolinyl radical;

2 1

R is a hydrogen atom or an alkyl radical, as for R

indicated or an aryl radical, as indicated for R or
an aralkyl radical, e.g. B. a benzyl radical and

R is a hydrogen atom or a methyl radical.

Polymers with a high refractive index can be produced by photopolymerizing a monomer of the formula given:

R ³ OR ^{2 1} I '

, = C-C-S-CH-

Ar-R ¹

where mean:

Ar is an arylene radical;

R is a hydrogen or halogen atom or an alkyl, alkoxy, amino, sulfide, sulfoxide, sulfonate, aryl or heterocyclyl radical, as stated;

R is a hydrogen atom or an alkyl, aryl or aralkyl radical, as indicated and

R is a hydrogen atom or a methyl radical.

The polymers according to the invention consist of 5 to 100 mol-I Monomers of the specified type and from 0 to 95 mol of copolymerizable ethylenically unsaturated monomers. The polymers that can be produced are practically colorless and transparent polymers with a refractive index greater than 1.60.

Due to the high refractive index, such polymers are particularly suitable for the production of optical components such as suitable for example lenses.

In the case of the "alkyl residues", "aryl residues" and "arylene residues" mentioned here they are optionally substituted radicals, d. H. the alkyl, aryl and arylene radicals can optionally be substituted, d. H. they can be, for example, methoxyethyl radicals, chlorophenylene radicals or bromonaphthylene radicals.

Examples of new thioacrylate monomers according to the invention which can be used for the production of advantageous polymers,

S- (1-naphthylmethyl) thioacrylate;

S- (2-naphthylmethyl) thioacrylate;

S- (1-naphthyl methyl) thiomethacrylate;

S- (1-kaphthyl) ethyl thioacrylate and

S-CI-Bromo-Z-naphthylmethylhioacrylate.

Particularly advantageous monomers according to the invention correspond the following structural formulas:

Cll ₂ = CH-CS-CH ₂

CH ₂ = CH-CS-CH

The monomers according to the invention can be prepared by Heating of the corresponding mercaptan, for example 1- (naphthylmethyl) mercaptan with a molar amount of up to 20% Excess bicycloheptene carbonyl chloride in an organic Solvent, e.g. methylene chloride, at a temperature from 30 to 50 ° C., an acid-binding amine, for example diisopropylethylamine, being slowly added to the mixture.

The product is then distilled under conditions that promote the cleavage of cyclopentadiene, for example in vacuum at 200 to 300 ⁰ C, whereby, for example, S- (1-naphthylmethyl) thioacrylate receives the monomers, in good yields.

The starting material, namely Bicycloheptencarbonylchlorid, can be prepared by stirring cyclopentadiene with one to 20ligen molar excess of acryloyl chloride and an organic solvent, such as methylene chloride at reduced temperature, for example -70 to -85 ⁰ C, followed by bringing the reaction mixture slowly to room temperature . The acid chloride product is then isolated by distillation.

The monomers of the invention have melting points of less than or equal to SO ⁰ C. monomers having melting points above 50 C or form bubbles lead to a non-uniform crystallization when they are polymerized in bulk.

Bubbles and crystals in the polymer produced lead to light scattering and a loss of image sharpness in the optical components they are used to manufacture.

Examples of copolymerizable ethylenically unsaturated monomers, which can be used to make the polymers are

for example alkyl acrylates and methacrylates, ζ. B. methyl acrylate, Ethyl acrylate, propyl acrylate, butyl acrylate, benzyl methacrylate and butyl methacrylate; Vinyl ester, vinyl amide ^, vinyl nitrile, Vinyl ketones, vinyl halides, vinyl ethers, olefins and diolefins, for example acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, acrylamide, methacrylamide, vinyl chloride, methyl vinyl ketone, Fumaric acid ester, maleic acid ester and itaconic acid ester, 2-chloroethyl vinyl ether, dimethylaminoethyl methacrylate, 2-IIydroxyethyl methacrylate, N-Vinyl sue an amide, N-Vinylphthal imid, N-vinyl pyrrolidone, butadiene and ethylene.

Preferred monomers which are used to produce the polymers are, for example, acrylates and methacrylates. As whole Benzyl methacrylate has proven to be a particularly advantageous comonomer.

The new polymers can be produced by adding a comparatively small amount of a photoinitiator (0.001-1.0 percent by weight), for example benzoin methyl ether, to the new Monomer or a mixture of preferably 50 to 100 mol% of the new monomer and 0-50 mol% of a copolymerizable, ethylenically unsaturated monomers as described above. The polymerization of the mixture can, for example, at temperatures from 20 to 30 C, by irradiation with a UV lamp, the light of the near ultraviolet range radiates.

The polymers according to the invention have a refractive index of over 1.60, typically from 1.60 to 1.70. As already mentioned, the use of polymers with a refractive index greater than 1.60 enables the use of optical components, which are considerably thinner than conventionally manufactured components.

Other customary ones can also be used to produce the polymers Polymerization processes can be used. One of these polymerization processes is the so-called thermal polymerization, a Polymerization by irradiation with electron beams and polymerization by irradiation with high-energy gamma radiation. Examples of polymers according to the invention are:

Poly / S- (1-naphthylmethyl) thioacrylate; Poly / S- (2-naphthylmethyl) thioacrylate 7;

Poly / S-O-naphthylmethylthioacrylate-cobenzyl methacrylate7;

Poly / S- (2-naphthylmethyl) thioacarylate-cobenzyl methacrylate7

The new polymers according to the invention can, as already set out to use in an excellent manner for the production of optical components. Under "optical components" are included Understand the parts of optical devices or devices whose function is to bend or refract light. Under “Optical components” are therefore to be understood as elements or materials that reflect, diffract, deflect or transmit light capital. Preferably, however, "optical components" are to be understood as components in which changes in the light-refracting or light-diffractive ability reduce the usability of the Effect components. As used herein, "diffraction" or "refraction" is defined as the deflection of a beam of light or an energy wave from a straight path when passing from one medium (e.g. air) into another medium (such as for example glass or another optical material) in which the Speed of light or the energy wave is different, at an oblique angle.

- ίο -

As used herein, the term "optical device" or "optical device" is a collection of manufactured parts into one complete Device, device, apparatus, machine or structure or unit of a machine that for example can be used for scientific study or the use of electromagnetic radiation. "Optical components" are to be understood as meaning refractive or diffractive materials or elements, for example Lenses, lens adhesives, prisms, mirrors, fixed light pipes, Light guides, fiber optics, phase retardation plates and the like.

"Prisms" are to be understood as transparent bodies, some of which are delimited by two flat surfaces which do not run parallel to one another, with such bodies or elements in addition can be used to deflect or disperse a beam of light. Prisms can be used, for example, in Telescopes, binoculars, beam splitters, range finders, spectroscopes, spectrographs, spectrophotometers, refractometers and anamorphic systems.

A "mirror" here refers to bodies or elements with a polished or smooth surface (e.g. glass), capable of producing images through reflection. Mirrors can be used, for example, in telescopes, beam splitters, Rangefinders, reflective microscope lenses and Compaction systems.

Under a "fixed light pipe" or a "fixed light guide" is to be understood as a transparent body that tapers to form a cone for the internal reflection of an incident Meridional ray on the untapered end of the cone from the conical wall at progressively smaller angles of incidence until it is fed to the tapered end of the cone, for example, as described in the book by Smith "Modem Optical Engineering ", 1966, Chapter 9. Light guides and light pipes

can be used to enlarge the field of view of a
Radiometer with a small detector.

A "light guide" is a transparent body or element with practically tubular tracks made of a material of higher refractive index, enclosed by a material of lower refractive index, usable for an internal reflection of an incident meridional beam at the entrance end of the Walls of the tubular webs at practically the same angles of incidence up to the feed to the exit end of the conductor, as described, for example, in US Pat. No. 3,809,686. Such light guides can be used, for example, in electronic components for coupling or connecting simple optical circuits
as well as without capacitive effects.

As is well known, "fiber optics" are defined as transparent bodies in the form of elongated polished cylinders in which light strikes the cylinder walls at an angle of incidence greater than the critical angle for total internal reflection, which is used to divert light from one end to the at the other end without significant loss, either in the form of a single fiber or in the form of a flexible bundle of fibers, as described, for example, by Smith in "Modern Optical Engineering", 1966, chapter 9. Fiber optics are known to be used in medical diagnostic instruments, for example
flexible gastroscopes, used in fire detection systems for the transmission of signals to a sensor behind a heat shield in data processing devices for scanning holes punched in cards or for scanning markings on test forms, as well as in photometers and colorimeters as flexible probes for a fixed sensor .

A "phase retardation plate" is defined as a transparent one Body that is used to produce phase shifts in incident radiation, resulting in elliptical or circularly polarized light. Phase retardation plates can be made up of a pair of movable biaxial crystals in the form of Wedges with vertically aligned optical axes, for example Babinet compensators, Soleil compensators and the like. Exist. On the other hand, the desired phase shift can also be generated by a total internal reflection in a phase retardation plate, for example a Fresnel rhombus. Various phase retardation plates are described, for example by Kingslake, in "Applied Optics and Optical Engineering", 1965, Volume I, Chapter 9. Phase retardation plates are used in ellipsometers to study the reflective characteristics of metals and the properties of surface films of liquids with polarized light.

According to a particularly advantageous embodiment of the invention, the monomers and polymers are used as starting compounds for Used in making lenses. As is well known, a "lens" is a transparent body with two opposing bodies regular surfaces that are either both curved or one of which is curved and the other is flat and which either can be used individually or in combination in optical instruments to produce images by focusing Rays of light. It has been shown that due to the higher refractive index of these polymers it is possible to produce lenses, which are thinner than lenses made from polymers with a refractive index below 1.60, z. B. Polymethyl methacrylate, which has a refractive index of 1.49 to 1.50 has.

The lenses according to the invention are not only thinner than conventional ones Wise made lenses, but also require less curvature, take up less space and thus allow in the case of lenses made up of several elements, greater design options. It is also used to manufacture them a lesser one. Amount of polymer used, which has a cost-saving effect.

Monomers of the invention are therefore advantageously suitable for the production of optical components by polymerization in bulk. The polymer obtained in this way forms the material from which the optical component is made or made can.

According to a particularly advantageous embodiment of the invention, a lens made of a polymer according to the invention such as produce as follows:

A mixture of 5 to 100 mol% of a.5 according to the invention Monomers, for example S- (1-naphthylmethyl) thioacrylate,

0 to 95 mole ⁰ "of a copolymerizable ethylenically unsaturated monomer such as benzyl methacrylate and a relatively small amount of a photoinitiator is prepared as a starting mixture. A particularly advantageous molar ratio of the mixture components reads, for example, with S- (1-naphthylmethyl) thioacrylate: benzyl methacrylate of 84:16. A mold, for example a concave glass lens, is filled with the mixture, after which the mold is covered with a glass plate. The mixture is then polymerized by exposure to near ultraviolet light. In this way, a clear and transparent lens can be obtained which is made from the polymer according to the invention with a refractive index of over

1, 60 consists.

The following examples are intended to further illustrate the invention.

example 1

A mixture of 66 g (1 mol) of cyclopentadiene and 500 ml of methylene chloride was stirred with 90 g (1 mol) of acryloyl chloride at dry ice temperature (-78.5 ° C.), whereupon the mixture was slowly warmed to room temperature over a period of 24 hours. The reaction product was then distilled. The thus obtained bicyloheptene carbonyl chloride was then reacted with 1- (naphthylmethyl) mercaptan and heated to reflux temperature in methylene chloride (boiling point 40-41 ° C.), one equivalent of diisopropylethylamine being slowly added to the mixture. The product was then distilled in vacuo, using an oil bath at 250 ° C., during which cyclopentadiene was split off and S- (1-naphthylmethyl) thioacrylate was obtained in good yield. The reaction product was a liquid at room temperature, ie 20 ^{° C.} Thin-layer chromatography (hexane / ether in the ratio 50:50, silica gel) of the monomer obtained gave an Rr value of 0.09 to 0.72. An infrared spectral analysis of the monomer obtained gave the following absorption bands: 1677 cm (s), 1620 cm (m), 1519 cm (w), 1400 cm ¹ (s), 1175 cnf ¹ (m), 1014 cm ¹ (s) and 780 Cm ^-1 Cs).

A nuclear magnetic resonance spectral analysis of the obtained

Monomers gave a complex multiplet at 7.58 (7H), a

Doublet at 6.28 (2H), a triplet at 5.48 (1H) and a singlet at 4.58 (2H).

Example 2

A mixture of 34 g of S- (1-naphthylmethyl) thioacrylate, 5 g benzyl methacrylate and 0.2 g benzoin methyl ether as photo

initiator and 0.3 g Aerosol OT (mold release agent) American Cyanamid product of the following formula:

Na-HO ₇ S-CHCH ₀ COCH-CH-CJI _n οι ζ ζ 4 y

C = O

O-CH ₂ CH-C ₄ H ₉

was produced. The mixture was then made into a mold from a concave glass lens, filled and covered with a 7.62 mm thick glass plate. The mixture was then by irradiation with a UV lamp of 15 watts, which emitted UV light of the near ultraviolet range and at a distance of 10.1 cm had been set up, polymerized. In this way a clear and transparent lens was obtained.

Claims (6)

320G775. No. 1 Dr r kh nat j brand iss EASTMAN KODAK COMPANY patrntanwai / i State Street SOoo münc-πκν ^ Rochester, New York State, United States of America thiwhhchsth. η ΤΗΙ, ΙβΙ'ΌΝι (OHO) 2OHÜO7 TIOl .HX: Π a: «Kän (|> mwo d) 25 · February 1982 25/65 New polymers and their use for the production of optical elements Patent claims 1. Polymer, characterized in that it is built up to (a) 5 to 100 MoI-I from recurring units of the Formula: R ³ -E CH ₂ -c-ίο = 0 I 2 s-cH-ir Ar-R ¹ where mean: Ar is an arylene radical, R is a hydrogen or halogen atom or an alkyl, Alkoxy, amino, sulfide, sulfoxide, sulfonate, aryl or heterocyclyl radical; HANKVKHIUNOUNtJ: I) KUTKCtIB ΗΛΝΚ ΛΟ, 1''11, IAIyIO MONtTItCN, ACCOUNT NH. 27 IO IO1 IIU..Z 7007 (1010) _ ο - R is a hydrogen atom or an alkyl, aryl or aralkyl radical and R is a hydrogen atom or a methyl radical and (b) 0 to 95 mol from copolymerizable ethylenically unsaturated monomers. 2. Polymer according to claim 1, characterized in that in the given formula Ar represents a phenylene, naphthylene, anthrylene, perylenylene or acenaphthenylene radical. 3. Polymer according to claim 1, characterized in that in the given formula Ar is a naphthylene radical and R, R and R represent hydrogen atoms. 4. Polymer according to claim 1, characterized in that it is built up is composed of (a) units of the formula given and (b) acrylate or methacrylate units. 5. Polymer according to claim 1, characterized in that the recurring units (a) are derived from a monomer with a melting point of 50 ⁰ C or below and that the polymer has a refractive index of greater than 1.60. 6. Use of polymers according to Claims 1 to 5 for the production of optical elements, in particular lenses.