Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/16—Catalysts
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
  • G02B1/041—Lenses
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/089—Reaction retarding agents
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/16—Catalysts
  • C08G18/18—Catalysts containing secondary or tertiary amines or salts thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/38—Low-molecular-weight compounds having heteroatoms other than oxygen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/38—Low-molecular-weight compounds having heteroatoms other than oxygen
  • C08G18/3855—Low-molecular-weight compounds having heteroatoms other than oxygen having sulfur
  • C08G18/3876—Low-molecular-weight compounds having heteroatoms other than oxygen having sulfur containing mercapto groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
  • C08G18/75—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
  • C08G18/75—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic
  • C08G18/758—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing two or more cycloaliphatic rings
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
  • G02B1/041—Lenses
  • G02B1/043—Contact lenses
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2125/00—Compositions for processes using internal mould release agents
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
  • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
  • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
  • G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
  • G11B7/253—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates
  • G11B7/2533—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising resins

Definitions

• the present invention relates to a polymerization catalyst for polythiourethanes, a polymerizable liquid composition containing it and a process for the production of organic polythiourethane glass with a high refractive index, good optical and physico-mechanical properties starting from said polymerizable liquid compositions; the invention also relates to organic glass obtained from the polymerization of said compositions by mould casting.
• the first component (A) contains at least one cycloaliphatic diisocyanate monomer
• the second component (B) contains one or more polythiols having a molecular weight ranging from 100 to 1,000 g/moles, and a functionality ranging from 2 to 5
• the third component (C) is a polymerization catalyst which does not contain organometallic compounds.
• ADC ADC-based on the commercial success of ADC is due not only to the good properties of the polymerized products, but also to the relatively simple production technique of the manufactured products, known as “casting” or “manual casting”.
• Polythiourethanes are, in turn, well-known as resins having a high refractive index, cited, for example, in EP271839, one of the first papers which describes the reaction of isocyanates with sulfur containing compounds to give polythiourethanes.
• the main objective of EP271839 is to find a suitable internal mould release agent, as external mould release agents cause various surface defects.
• EP 271839 describes internal mould release agents selected from non-ionic fluorinated surfactants, non-ionic silicon surfactants, alkyl ammonium quaternary salts, metal salts of higher fatty acids and esters of phosphoric acid, in an amount of 10 to 10,000 ppm with respect to the total mixture.
• Organometallic catalysts containing tin are currently commonly used in industry, but as they represent a potential risk for both human beings and for the environment, due to their toxicity and bio-accumulation, various alternatives based on catalysts not containing tin, have recently been proposed.
• WO2010001550 describes the use of a mixture of a zinc compound, a compound having general formula (1) and a compound having general formula (2)
• JP 2006199885 describes thiol complexes of Si, Ge, Sn, Zr or Ti.
• Non-metal catalysts are also described in JP2008074957 which provides for mixtures of amines and substituted sulphonates. These mixtures however do not operate as described in this document. In fact, the mixing of the various components does not lead to obtain polymerizable liquid compositions, but the premature formation of a viscous gel which proves to be unsuitable for the production of optical articles on an industrial scale.
• JP2008074958 on the contrary, the amine compounds are combined with phosphates. More specifically, JP2008074958 discloses a system which provides a salt of a trifunctional amine and an alkyl ester of a phosphoric acid.
• the present invention allows both objectives to be achieved. It relates, in fact, to a simple casting process for the production of transparent manufactured products having a high refractive index, made of plastic thermosetting material of the polythiourethane type with excellent physico-mechanical properties, starting from polymerizable liquid compositions which represent a further objective of the present invention.
• the present invention has therefore surprisingly found a new catalytic system, not containing organometallic catalysts based on tin, which is simpler and which guarantees enhanced results in terms of simplicity and facility in effecting the productive process, a good release from the mould, a good reactivity, at the same time guaranteeing a product with a high refractive index, with good optical properties, an improved toughness and impact strength.
• R1, R2 and R3, equal to or different from each other, represent a C 1 -C 20 linear or branched aliphatic group or a C 3 -C 20 cycloaliphatic group, said groups possibly containing heteroatoms such as N, O, P, S, halogens;
• a further object of the present invention therefore relates to polymerizable liquid compositions of the polythiourethane type, essentially consisting of three components (A), (B) and (C), wherein component (A) contains at least one cycloaliphatic diisocyanate monomer wherein the weight percentage of free isocyanate groups in said component (A) ranges from about 20% to about 50% by weight, preferably from about 25% to about 40% by weight, with respect to the total weight of component (A); component (B) contains at least one polythiol having a molecular weight ranging from 50 to 1,200 g/mole, preferably from 100 to 1,000 g/mole, and a functionality ranging from 2 to 5, preferably from 2 to 4, said components (A) and (B) being present in a weight ratio varying from 0.5:1 to 2:1, preferably from 1:1 to 2:1; component (C) being a catalyst according to the present invention.
• component (A) contains at least one cycloaliphatic diisocyanate monomer wherein the weight percentage
• Additives can be present in one of the two components (A) and (B), or in both, such as light stabilizers, antioxidants, UV absorbers, anti-fog agents, radical scavengers, dyes for colour correction, etc.
• the polymerizable composition according to the present invention does not require the separate addition of internal mould release agents such as non-ionic fluorinated surfactants, non-ionic silicon surfactants, alkylammonium quaternary salts or monoesters of phosphoric acid.
• a filtration phase c) to remove any possible pollutants dispersed in the mixture, said filtration phase also being effected alternatively or additionally, on the single components (A) and (B) before the mixing phase b);
• the polymerization is generally carried out by gradually heating the moulds filled with the liquid composition, passing from low to high temperatures within a time span varying from a few hours to numerous tens of hours, as will be seen hereunder.
• the presence of a catalyst is necessary, which ensures a good heat control as the temperature increases, but which, at the same time, has a high polymerization efficiency so as to allow the completion of the polymerization reaction and the production of a polymer characterized by optimal physico-mechanical properties, such as heat resistance and impact strength.
• a further object of the present invention relates to the manufactured products or optical articles comprising the organic glass obtained by the casting and polymerization process of the polymerizable composition, such as, for example, ophthalmic lenses and optical filters, sheets, displays, sun glasses, etc.
• the casting technique into a mould with which organic glass is obtained according to the present invention starting from polymerizable liquid compositions of the polythiourethane type can be of the manual type, or it can avail of mixing-dispensing machines.
• the manual casting process for the production of organic glass according to the present invention comprises the following phases:
• Filters of the propylene or nylon cartridge type having a porosity of 0.5-1 absolute microns, are suitable for the purpose.
• the filtration can be effected on the single components, separately, before the mixing phase.
• Phase d) is then effected, in which the moulds are filled by gravity casting, or by means of mechanical pumps or by applying a gaseous pressure, followed by the subsequent polymerization phase e) of the liquid composition by thermal treatment of the mould with temperatures varying from 20 to 140° C., preferably from 30° C. to 130° C. and with polymerization times which normally vary from 1 hour to 40 hours, preferably from 3 to 30 hours.
• the casting can be effected using moulds of various materials such as, for example glass or metals.
• Suitable metallic moulds can be produced in stainless steel, nickel, aluminium, copper, chromium, silver and gold.
• the manual casting technique applied in the process according to the present invention is completely similar to the casting technique used in the case of the ADC monomer but, with respect to this, the casting and polymerization process according to the present invention offers the advantage that the preparation of the polymerizable composition is effected at temperatures close to room temperature.
• the casting of the polymerizable composition according to the present invention can also be carried out with the use of a mixing-dispensing machine.
• FIG. 1 A scheme of the apparatus is provided in FIG. 1.
• the machine essentially consists of:
• the temperature in the transfer and dosage phases of the above components (A)+(C) and (B) and the dispensing rate are selected on the basis of the physico-chemical properties of the composition used, the type of optical article to be produced and its complexity.
• the polymerizable liquid composition according to the present invention therefore allows articles characterized by a high refractive index, excellent optical and physico-mechanical properties to be produced on an industrial scale by means of a simple and inexpensive casting process.
• the stability over time of the polymerizable liquid composition defined with the term “pot-life”, which indicates the time range from the preparation of the mixture in which the viscosity remains sufficiently low to allow its use, becomes a critical parameter.
• the pot-life does not represent a critical parameter in the case of casting with a mixing-dispensing machine as the catalyzed solution is immediately injected into the mould.
• the catalyst of the polymerizable liquid composition according to the present invention allows a high flexibility to be obtained in the catalysis of the polymerization reaction, thus allowing a variable pot-life, more or less long, to be envisaged in relation to the casting process selected, together with good mould release properties which make it suitable for an industrial product.
• the present invention relates to a casting and polymerization process of polymerizable liquid compositions of the polythiourethane type for the production of organic glass with a high refractive index, having good optical and physico-mechanical properties.
• the polymerizable liquid composition according to the present invention is composed of component (A), component (B) and component (C).
• Component (A) of the polymerizable composition according to the present invention contains at least one cycloaliphatic diisocyanate monomer or a mixture of cycloaliphatic diisocyanate monomers, wherein the weight percentage of free isocyanate groups in said component (A) ranges from about 20% to about 50% by weight with respect to the total weight of component (A) and, preferably, ranges from about 25% to about 40% by weight with respect to the total weight of component (A).
• cycloaliphatic diisocyanate monomers corresponding to component (A) of the composition according to the present invention are cyclohexane diisocyanate, methyl cyclohexane diisocyanate, bis(isocyanate methyl)cyclohexane, 4,4′-methylene bis(cyclohexyl isocyanate), 4,4′-isopropylidene bis(cyclohexyl isocyanate), 4,4′-dicyclohexylmethane diisocyanate), bis(isocyanate cyclohexyl)methane, bis(isocyanatecyclohexyl)-2,2-propane, bis(isocyanatecyclohexyl)-1,2-ethane, 3-isocyanate methyl-3,5,5-trimethyl cyclohexyl isocyanate commonly known as isophorone diisocyanate, 2,5(6) diisocyanate-methylbicyclo(2,2,1)heptane
• the cycloaliphatic diisocyanate monomer of component (A) of the composition according to the present invention is preferably selected from 4,4′-methylene bis(cyclohexyl isocyanate) and bis(isocyanate methyl)cyclohexane.
• Component (B) of the polymerizable composition according to the present invention contains one or more polythiols having a molecular weight ranging from 50 to 1,200 g/moles and preferably from 100 to 1,000 g/moles and a functionality from 2 to 5 and preferably from 2 to 4, said polythiols being selected from polythiols having general formula (3):
• R represents alkylidene groups having from 1 to 6 carbon atoms, the same or different;
• R1 represents alkyl groups having from 1 to 10 carbon atoms, the same or different;
• n ranges from 1 to 6;
• m varies from 1 to 6;
• p varies from 1 to 4;
• q is equal to 0 or 1 and p+q is equal to 4;
• polythiols having general formula (4):
• R represents an alkylidene group having from 1 to 6 carbon atoms; n ranges from 1 to 6; m ranges from 1 to 6; and/or polythiols having general formula (5):
• R1 —(CH 2 ) n —SH
• R2 —S—(CH 2 ) n —SH
• R3 —R—S—(CH 2 ) n —SH
• R is an alkyl group having from 1 to 10 carbon atoms and n ranges from 1 to 3.
• thiols having general formula (4), as component (B) of the polymerizable composition according to the present invention are:
• thiols having general formula (5), as component (B) of the polymerizable composition according to the present invention are:
• Examples of preferred thiols are 2,3-bis((2-mercaptoethyl)thio)-1-propanethiol and a mixture of 2,3-bis((2-mercaptoethyl)thio)-1-propanethiol and ethylene glycol-di(3-mercaptopropionate)
• components (A) and (B) preferably used are 4,4′-methylene bis(cyclohexyl isocyanate), as component (A), ethylene glycol-di(3-mercaptopropionate), and 2,3-bis(2-mercaptoethyl)thio)-1-propanethiol, as component (B).
• the organic glass or optical articles according to the present invention are prepared by the polymerization reaction of components (A) and (B) according to suitable weight ratios which generally vary from 0.5:1 to 2:1, in the presence of a suitable catalyst which forms component (C) and possibly further additives such as those listed below.
• Component (C) of the polymerizable liquid composition according to the present invention is a polymerization catalyst which does not contain organometallic compounds and consists of a mixture of
• R1, R2 and R3, equal to or different from each other, represent a C 1 -C 20 linear or branched aliphatic group, or a C 3 -C 20 cycloaliphatic group, said groups possibly containing heteroatoms such as N, O, P, S, halogens;
• R2 and R4 equal to or different from each other, represent a linear or branched C 1 -C 20 aliphatic group, or a C 3 -C 20 cycloaliphatic group
• R3 and R5, equal to or different from each other represent a C 1 -C 3 alkylidene group and m and p are equal to 0, 1 or 2
• the tertiary aliphatic amine and disubstituted phosphoric acid being present in a molar ratio varying from 1/1.3 to 1/20 and, preferably, from 1/1.5 to 1/15.
• Amine compounds having formula (1) which can be used for the purposes of the present invention are tertiary aliphatic amines such as, for example: triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, triisobutylamine, benzyldimethylamine, n-methyl-morpholine, dimethylcyclohexylamine, 1,2,2,6,6-pentamethyl-4 -piperidinol, 1,2,2,6,6-pentamethyl-4-hydroxyethyl-4-piperidinol, dimethyldipropylenetriamine, pentamethyldiethylenetriamine, bis(2-dimethylaminoethyl)ether, N-methyl morpholine, triethylenediamine, bicyclo-octane diamine (DABCO), etc.
• tertiary aliphatic amines such as, for example: triethylamine, tri-n-propylamine, tri
• Sterically hindered amines such as amines known as HALS and in particular liquid tertiary amines, can also be used, such as, for example:
• Examples of preferred amines according to the present invention are triethylamine, tri-n-propylamine, tri-isopropylamine, and mixtures of methyl-1,2,2,6,6-pentamethyl-4 piperidinyl sebacate (preferably 25% by weight) and bis(1,2,2,6,6-pentamethyl-4 piperidinyl) sebacate (preferably 75% by weight).
• disubstituted phosphoric acid having formula (2) which can be used for the purposes of the present invention are: dimethylphosphate, diethylphosphate, diisopropylphosphate, dibutylphosphate, dioctylphosphate, bis(2-ethylhexyl)phosphate, diisodecylphosphate, methoxyethyl-ethoxyethylphosphate, methoxyethyl-propoxyethylphosphate, ethoxyethyl-propoxyethyl phosphate, ethoxyethyl-butoxyethyl phosphate, di(methoxy-ethyl)phosphate, di(ethoxyethyl)phosphate, di(propoxy-ethyl)phosphate, di(butoxyethyl)phosphate, di(hexyloxy-ethyl)phosphate, di(decyloxyethyl) phosphate, di(methoxy-propy
• the disubstituted phosphoric acid used in the catalyst and therefore in the polymerizable liquid composition and process according to the present invention is preferably selected from C 8 diester of phosphoric acid, C 10 diester of phosphoric acid and/or mixtures thereof.
• Examples of preferred catalysts are mixtures of triethylamine and bis(2-ethylhexyl)phosphate or mixtures of methyl-1,2,2,6,6-pentamethyl-4 piperidinyl sebacate (25% by weight) and bis(1,2,2,6,6-pentamethyl-4piperidinyl)sebacate (75% by weight) with bis(2-ethylhexyl)phosphate.
• the quantity of component (C) ranges from 0.1 to 2% by weight with respect to the total weight of the polymerizable composition and preferably from 0.2% to 1.5% by weight with respect to the total weight of the composition.
• component (A) or component (B) or both can be incorporated into component (A) or component (B) or both, before the mixing phase or they can be added during the mixing phase of the two components.
• Non-limiting examples of these additives are dyes, including photochromatic dyes, bluing agents, UV absorbers of the family of benzotriazoles, IR absorbers, antioxidants, anti-fog agents and radical scavengers.
• a further improvement in the mechanical properties such as hardness, impact strength and abrasion resistance can be obtained by the addition of inorganic nanoparticles based on salts, or preferably based on zinc oxide, cerium oxide, silicon oxide, aluminium oxide, titanium oxide or zirconium oxide.
• the polymerizable composition according to the present invention does not require the separate addition of internal mould release agents such as non-ionic fluorinated surfactants, non-ionic silicon surfactants, quaternary alkylammonium salts or monoesters of phosphoric acid, as it is in itself inherently provided with self-release properties.
• internal mould release agents such as non-ionic fluorinated surfactants, non-ionic silicon surfactants, quaternary alkylammonium salts or monoesters of phosphoric acid, as it is in itself inherently provided with self-release properties.
• An object of the present invention also relates to the organic glass obtained with the casting and polymerization process of said compositions.
• a further object of the present invention relates to end-products or optical articles comprising the organic glass obtained with the casting and polymerization process of the polymerizable composition according to the present invention, as previously described, such as, for example, ophthalmic lenses and solar filters, Fresnel lenses, protective and safety shields, displays, substrates for optical disks, display panels and video display units, optical guides, components for mobile phones, transparent tubes.
• end-products or optical articles comprising the organic glass obtained with the casting and polymerization process of the polymerizable composition according to the present invention, as previously described, such as, for example, ophthalmic lenses and solar filters, Fresnel lenses, protective and safety shields, displays, substrates for optical disks, display panels and video display units, optical guides, components for mobile phones, transparent tubes.
• Said end-products or optical articles can be surface hardened with antiscratch coatings or they can be made non-reflective with techniques and materials normally used for ADC end-products.
• the extremely low viscosity values of the polymerizable compositions according to the present invention combined with a good pot-life of the composition itself, allow perfectly homogeneous mixtures of the various components to be obtained, consequently allowing defect-free optical end-products to be produced on an industrial scale.
• This characteristic is essential in particular for the production process of organic glass by means of the manual casting technique, object of the present invention, as, thanks to this, it is possible to fill a considerable number of moulds in short times, thus satisfying the fundamental requisite for industrial-type production.
• the polythiourethane thermosetting plastic materials i.e. the organic glass obtained with the process according to the present invention, have excellent optical properties and an excellent processability, similar to those which characterize ADC polymers but, with respect to the latter, they are equipped with a much higher impact strength and toughness. These characteristics make the material suitable for the manufacturing of complex end-products which cannot be produced with ADC polymers.
• the quantity of catalyst and the molar ratio between the two components tertiary amine and disubstituted phosphoric acid can be defined and optimized in the process according to the present invention so as to obtain a pot-life of the polymerizable composition which varies from short to sufficiently long and, at the same time, obtain a reduced polymerization time in the mould, which is economically advantageous, and makes the catalyst and therefore the process according to the present invention suitable for industrial production, as will appear evident from the following experimental examples.
• the pot-life at 25° C. of the polymerizable composition according to the present invention was evaluated by measuring the viscosity in consecutive times, starting from the preparation.
• the pot-life is defined, within the scope of the present invention, as the time range necessary for reaching this viscosity value. Consequently according to the previous definition, an adequate pot-life at 25° C. is equal to at least 2 hours.
• the polymerizable liquid compositions were then subjected to polymerization by means of thermal treatment in a forced circulation oven, with a gradual temperature rise as indicated in the following experimental examples.
• the physico-mechanical properties were determined on the polymerized products or organic glass thus obtained; in particular the following characteristics were determined:
• Haze % (ASTM D-1003), determined with a Macbeth Color i5 spectrophotometer.
• HDT Deflection temperature under flexural load 1.82 MPa
• composition nr. 1 was prepared according to the present invention, consisting of components (A), (B) and (C) in the quantities indicated in Table 1.
• Component (A) consists of 4,4′-methylene bis(cyclo-hexyl isocyanate).
• Component (B) is obtained by mixing at 25° C. and 10 mbar of pressure: ethyleneglycol-di(3-mercaptopropionate) and 2,3-bis((2-mercaptoethyl)thio)-1-propanthiol.
• Component (C) is obtained by mixing at 25° C., triethylamine and bis(2-ethylhexyl) phosphate.
• component (A) and 9 g of component (C) previously prepared and consisting of 0.82 g of TEA and 8.18 g of Bis(2-EHP) (molar ratio TEA/Bis(2-EHP) 1/3.1), were charged into a two-necked jacketed flask, equipped with a thermometer and magnetic stirrer.
• the whole solution was mixed at 25° C. for about 30 minutes, at an absolute pressure of 10 mbar, obtaining a polymerizable composition according to the present invention, on which the pot-life was evaluated with time at 25° C., by means of viscosity measurements at the same temperature (Table 2).
• the data indicate a pot-life higher than 4 hours and therefore suitable for the production of optical articles on an industrial scale with the manual casting technique.
• the polymerizable composition thus obtained was poured into glass moulds and subjected to polymerization in a forced circulation oven with a gradual temperature increase from 40° C. to 130° C. in 24 hours.
• the polythiourethane according to the present invention shows high refractive index values and a high Abbe number, excellent optical and physico-mechanical properties, the same or higher than those of the ADC polymer, in particular a density about 7% lower, an impact strength over 4 times higher and an HDT over 40° C. higher.
• compositions from nr. 2 to 5 were prepared according to the present invention, consisting of Components (A), (B) and (C) in the quantities and under the conditions indicated in Table 4.
• Composition n o 2 3 4 5 Component (A) H12MDI, g 1530 1500 1500 1500 Component (B) GDMP, g — 50 100 100 (mixture) DMPT, g 1000 950 900 900 Component (C) TEA, g 0.9 0.75 1.0 0.68 (mixture) Bis(2-EHP)g 3.75 3.75 8.0 6.8 Molar ratio TEA/Bis(2-EHP) 1/1.3 1/1.5 1/2.5 1/3.1
• the initial viscosity was measured on the degassed and limpid solutions thus obtained, and subsequently the viscosity, at the same temperature, in consecutive times, obtaining the values indicated in Table 5.
• the data indicate in each case a pot-life higher than 2 hours and consequently suitable for the production of optical articles on an industrial scale with the manual casting technique.
• the polymerizable compositions from nr. 2 to nr. 4 thus obtained were poured into glass moulds and subjected to polymerization in a forced circulation oven with a gradual temperature increase from 40° C. to 130° C. in 24 hours.
• Composition nr. 6 was prepared according to the present invention, consisting of Components (A), (B) and (C) in the quantities indicated in Table 7.
• Component (C) is obtained by mixing the following products at 25° C.:
• the data indicate a pot-life higher than 2 hours and consequently suitable for the production of optical articles on an industrial scale with the manual casting technique.
• the polymerizable composition nr. 6 thus obtained was poured into glass moulds and subjected to polymerization in a forced circulation oven with a gradual temperature increase from 40° C. to 130° C. in 24 hours.
• the transparent polythiourethane according to the present invention has excellent optical and physico-mechanical properties, completely analogous to those obtained with the polymerizable compositions of Example 1 of the present invention.
• compositions nr. 1C and nr. 2C consisting of Components (A), (B) and (C) in the quantities and under the conditions indicated in Table 10.

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