MXPA00010332A - Optical articles comprising isosorbide polyesters and method for making same - Google Patents

Abstract

An optical article made of a transparent polymer which includes terephthaloyl moieties, optionally, other aromatic diacid moieties;ethylene glycol moieties;isosorbide moieties;and, optionally, one or more other diol moieties, wherein the polymer has an inherent viscosity of at least about 0.35 dL/g as measured on a 1%solution (weight/volume) in o-chlorophenol at 25°C.

Description

OPTICAL ARTICLES COMPRISING ISOSORBIDE PQLIESTERS AND METHODS FOR THE ELABORATION FIELD OF THE INVENTION This invention relates generally to the field of optical articles, such as compact discs, and more specifically to optical articles comprising specific polymeric materials and to methods of making optical articles comprising these polymeric materials.

ANTECEDENTS OF THE TECHNIQUE Optical storage in the compact disk (CD) format has gained widespread use in the computer, advertising and consumer markets as a low-cost and convenient method of storing information. The digital information is stored in a substrate by means of pitting and grooves which are read with a laser light source. As optical storage technology advances to the Digital Versatile Disk (DVD), the density of the information in the substrate needs to be increased when making stings Ref: 123438 even smaller and closer to each other. An erasable CD also creates more demands on the resins used in CDs. Therefore, improvements are needed in the resins and in the manufacturing processes to make CDs and DVDs. In the CD and DVD manufacturing process, the information is encoded in the form of pitting and grooves that are duplicated from a stamper in a mold on a plastic substrate. The substrate is then metallized so that the laser reading is reflected from the coded stings. The CD after the stamping and metallization, is covered with a lacquer or resin which protects the disc and which can be marked with ink for labeling and identification. DVDs are similar to CDs in manufacturing, but they can also have a semi-reflective layer added to encode an additional layer of information on top of the first surface (replicated). For DVDs, two discs are joined together with a transparent adhesive to duplicate the information content. The DVD disc is then read from the top and bottom using two light sources. In the case of recordable CDs and DVDs, a continuous groove or track is molded into the substrate for laser tracking. A phase change material (a decolorizing solution or an inorganic alloy) is then coated in rotation or deposited on the plastic substrate. A metallic alloy, preferably gold, is deposited on the recording medium to reflect the reading laser beam. Finally, a coating is applied to protect the metal layer. The molding of CDs with fast cycle times requires a plastic resin with a special combination of rheological, mechanical, thermal, water absorption and optical characteristics. One of the most important properties is a low melting point viscosity, which can be obtained by reducing the molecular weight of the polymer.A viscosity with a low melting point allows rapid injection molding and also a rapid relaxation of biorefrigence and the mechanical stresses on the molded disc before the polymer solidifies.Mechanical properties such as stiffness, shrinkage and impact resistance are important to obtain molded discs that are flat, have good pit replication and are mechanically robust. Heat resistance is desirable because the compact discs are used and stored in uncontrolled environments, such as the interior of a car, where the temperatures can be very high.The low water absorption is also important so that the discs molded retain their performance characteristics with high humidity and temperature. Bonding to metal in an environment with high moisture content is important for a long-term storage capacity. The optical characteristics of the plastic material include low optical voltage coefficient and high optical transmission, so that the laser beam passes through the substrate and is reflected with minimal distortion. The main performance standards that compact discs must satisfy in relation to the fidelity of pit replication (information content), low birefringence in the substrate (optical signal fidelity) and flat disc condition (no bends in the rotating disc) . It is difficult for a plastic resin to satisfy all the above requirements. For example, melt viscosity polymers that have been reduced by decreasing molecular weight generally have poor mechanical properties. Many plastics have been proposed or used, including polycarbonates, acrylics, polyesters, polystyrene and copolymers of cyclic olefins. Bisphenol-A polycarbonate and acrylic polymers are the most widely used, mainly due to their high optical transmission, excellent mechanical properties (polycarbonates) and low birefringence (acrylics). However, these materials have many disadvantages that include a high optical tension coefficient (polycarbonates), high water absorption (acrylics) and poor metallization (acrylics). Therefore, there is a need for an improved optical quality plastic resin as a substrate material for compact discs. Plastics that can be used in CD and DVD ("optical plastics") have sufficiently good properties so that they can also be used in other optical articles. The term "optical articles", as used in the present, refers to articles that are used in optical applications. Optical articles deal with light, including the effects where light produces and experiences, and the generation, propagation and / or transmission of light are used. Optical plastics are plastics that have optical properties that make them suitable for use in optical articles. Optical items include lenses such as Fresnel lenses, instrument panel windows and covers, prismatic reflectors, optical fibers, CDs, DVDs, and transparent films and films. The molded lenses can be used for such applications as for example for directing light beams and images. Plastic lenses are useful because they can incorporate additional features and mechanical arrangements into the design of the lenses and because they are easy to produce by molding. The material requirements for the lenses are similar to those of compact discs.

The 1, 4: 3, 6-dianhydro-D-sorbitol diol, referred to in the following as isosorbide, the structure of which is illustrated below, is easily manufactured from renewable sources, such as sugars and. starches For example, isosorbide can be made from D-glucose by hydrogenation, followed by acid-catalyzed dehydration.

OH H Isosorbide has been incorporated as a monomer within the polyester which also includes terephthaloyl moieties. See, for example, R. Storbeck et al., Makromol. Chem., Vol. 194, p. 53-64 (1993); R. Storbeck et al., Polymer. vol. 34, p. 5003 (1993). However, it is generally considered that the secondary alcohols such as isosorbide have little reactivity and are sensitive to acid catalyzed reactions. See, for example, D. Braun et al., J. Prakt. Chem., Vol. 334, p. 298-310 (1992). As a result of poor reactivity, polyesters made with an isosorbide monomer and terephthalic acid esters are expected to have a relatively low molecular weight. Ballauff et al., Polyesters (Derived from Renewable Sources), Polymeric Materials Encyclopedia, vol. 8, p. 5892 (1996). Copolymers containing isosorbide portions, ethylene glycol portions and terephthaloyl moieties have been reported only rarely. A copolymer containing these three portions, in which the molar ratio of ethylene glycol to isosorbide is about 90:10, are reported in German Patent Application No. 1,263,981 (1968). The polymer is used as a minor component (approximately 10%) of a combination with polypropylene to improve the dyeability of polypropylene fiber. It is manufactured by melt polymerization of dimethyl terephthalate, ethylene glycol and isosorbide, but the conditions, which are described only in general terms in the publication, have not provided a polymer having a high molecular weight. The copolymers of these same three monomers have recently been described again, where it is observed that the glass transition temperature Tg of the copolymer is increased with the content of isosorbide monomer to about 200 ° C for the homopolymer of isosorbide terephthalate. The polymer samples are made by reacting terephthaloyl dichloride in solution with the diol monomers. This method provides a copolymer with a molecular weight that is apparently greater than that obtained in the German patent application described above, but is still relatively low when compared to other polyester polymers and copolymers. In addition, these polymers are manufactured by polymerization and solution and are therefore free of diethylene glycol portions as a polymerization product. See R. Storbeck, Dissertation Universitat Karlsruhe (1994); R. Storbeck et al., J. Appl. Poly er S ience, vol. 59, p. 1199-1202 (1996). U.S. Patent 4,418,174 describes a process for the preparation of polyesters useful as raw materials in the production of aqueous baked lacquers. The polyesters are prepared with an alcohol and an acid. One of the many preferred alcohols is dianhydrosorbitol. However, the average molecule weight of the polyesters is from 1000 to 10,000, and a polyester containing a dianhydrosorbitol moiety has not actually been made. U.S. Patent 5, 179, 143 describes a process for the preparation of compression molded materials. In addition, hydroxyl-containing polyesters are described herein. These hydroxyl-containing polyesters are listed to include polyhydric alcohols including 1, 4: 3, 6-dianhydrosorbitol. However, again, the highest molecular weights reported are relatively low, that is, from 400 to 10,000, and in fact a polyester containing the 1, 4: 3, 6-dianhydrosorbitol portion has not been made. Published PCT applications WO 97/14739 and W0 96/25449 disclose cholesteric and nematic liquid crystalline polyesters including isosorbide portions as monomer units. Such polyesters have relatively low molecular weights and are not isotropic.

BRIEF DESCRIPTION OF THE INVENTION Contrary to the teachings and expectations that have been published in the prior art, the isotropic, ie semicrystalline and amorphous or non-liquid crystalline copolyesters containing terephthaloyl moieties, ethylene glycol moieties, isosorbide moieties and, optionally, diethylene glycol moieties, are easily synthesized in molecular weights that are suitable for manufacturing manufactured products, such as films, beverage bottles, molded products, films and fibers, on an industrial scale. In a preferred embodiment, the number of terephthaloyl moieties in the polymer is in the range of from about 25% to about 50 mole% (moles% of the total polymer). The polymer may also include amounts of one or more aromatic diacid moieties such as, for example, those derived from isophthalic acid, 2,5-furanedicarboxylic acid, 2,5-thiophenecarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2, 7 acid. -naphthalenedicarboxylic acid, and 4,4'-benzoic acid, at combined concentrations of up to about 25 mol% (moles% of the total polymer). In a preferred embodiment, the ethylene glycol monomer units are present in amounts of about 5 mol% to about 49.75 mol%. The polymer may also contain portions of diethylene glycol. depending on the manufacturing method, the amount of diethylene glycol portions is in the range of about 0.0 mole% to about 25 mole%. In a preferred embodiment, the isosorbide is present in the polymer in amounts in the range of about 0.25 mole% to about 40 mole%. Also one or more diol monomer units may be included in amounts up to a total of about 45 moles? . Of course, all percentages depend on the particular application desired. Desirably, however, equimolar amounts of diacid monomer units and diol monomer units are present in the polymer. This equilibrium is desirable to obtain a high molecular weight. The polymers of these compositions have glass transition temperatures, as measured by differential scanning calorimetry, from about 85 ° C to about 196 ° C, with preferred compositions generally having Tg from about 90 ° C to about 165 ° C. The polymers have inherent viscosities of from about 0.35 to about 0.60 dl / g, preferably from about 0.4 to about 0.5 dl / g, measured in a 1% (w / v) solution in o-chlorophenol at 25 ° C. The polymers in this composition range are amorphous (or can be cooled to amorphous solder), transparent and have low birefringence. Polymer compositions which are amorphous because they are cooled, are slow to crystallize, even when heated above the glass transition temperature. The copolymer is formed into articles that can be used in optical applications (ie, optical articles). These articles include substrates for compact discs and DVDs and the finished structure thereof, including lenses, Fresnel lenses, instrument panel windows and covers, prismatic reflectors, films and thin and thick transparent films, optical fibers and the like. The preferred shaped articles are compact discs and DVDs, substrates for making CDs and DVDs, and lenses, including Fresnel lenses. Finished CDs and DVDs have pitting on the surface of the discs in a CD or DVD format. They also have a reflective layer (usually metal) and a protective coating, such as a lacquer. DVDs can also include additional layers to adapt to the DVD format, such as additional reflective or semi-reflective layers, additional protective layers and more than one disc stacked together. The copolymer is formed within these optical articles by one or more commonly used methods for forming and manufacturing plastics, which include injection molding, compression molding, extrusion through a die, which can be designed to manufacture fibers, films, sheets, bars and other shaped objects, calendering, engraving, embossing and injection / compression molding. Preferred manufacturing methods are injection molding and injection / compression molding, and the preferred shaped articles are discs for CD and DVD. The invention also comprises a method for making disks, CDs and DVDs, lenses and other optical articles in forming the polymer including portions of terephthalic acid, isosorbide, and ethylene glycol described above, in a disk or other form, by injection molding. . In the case of discs, the discs may have pre-molded stitches on the surface of the disc in a CD or DVD format during injection molding, or they may be injection molded / compression combined for read-only discs, or they may have only slots in the case of recordable discs. Stings or other marks readable with a laser can be generated on recordable discs by applying laser radiation focused on a coating that has changed (eg, been fused) by the focused laser. In all cases, the discs are additionally manufactured by application of other coatings and layers to make a finished CD or DVD. These coatings and layers include a reflective coating (usually a metal), a protective coating (for example a lacquer) or other reflective, semi-reflective or transparent layers or additional coatings and discs as needed to conform to the CD or DVD format. Optical articles shaped using the above polymers have many attractive properties, including high optical transmission in thick substrates, good pit replication, good metal adhesion, low birefringence resulting in low optical retardation in CD substrates, mechanical rigidity at high temperature, high heat distortion temperature, low shrinkage, low moisture absorption and good scratch resistance.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES OF THE DESCRIPTION The isotropic polyester polymer, described in detail in the following, can be made by melt condensation of a combination of monomers containing a portion of ethylene glycol, an isosorbide portion and a terephthaloyl portion. Small amounts of other mesomers may be added during the polymerization or may be produced as by-products during the reaction. In a preferred embodiment, the ethylene glycol monomer units are present in amounts of about 5 mole% to about 49.75 mole%, preferably 10 mole% to about 49.5 mole%, and most preferably about 25 mole% at about 48 mole%, than even more preferably from about 15 mole% to about 40 mole% and alternatively about 15 mole% to about 38 mole%. The polyester polymer can also contain monomeric units of diethylene glycol. Depending on the manufacturing method, the amount of diethylene glycol monomer units is in the range of from about 0.0 mole% to about 25 mole%, preferably, 0.25 mole% to about 10 mole%, and more preferably from 0.25 mole% to about 5 - Í5 -moles ?. Diethylene glycol can be produced as a byproduct of the polymerization process and can also be added to help accurately regulate the amounts of diethylene glycol monomer units that are in the polyester polymer. In a preferred embodiment, the isosorbide portions are present in the polyester polymer in amounts in the range of about 0.25 mole% to about 40 mole, preferably from about 0.25 mole% to about 30 mole%, and more preferable -about 0.5 moles? to 20 moles ?. Depending on the application, the isosorbide can be present in any desirable range such as 1 mol% to 3 moles ?, 1 mol? to 6 moles ?, 1 mol? to 8 moles ?, and 1 mole? to 20 moles ?. The lower limit of isosorbide in the above most preferred compositions without the optional comonomers other than ethylene glycol, is approximately the minimum amount of isosorbide necessary to return to the completely amorphous polymer, regardless of the procedure. Polymers with less than 12 moles? of isosorbide can become amorphous by cooling them from their molten condition. These are slow to crystallize under conditions where crystallization takes place. A higher concentration of isosorbide provides polymers that are amorphous and have a higher vitreous transition temperature (Tg). Polymers that are always amorphous and having higher Tg are preferred for use in environments where the optical articles may be exposed to elevated temperatures, which may result in crystallization in the compositions that have cooled to become amorphous. Optionally, one or more monomer units of another diol may be included in amounts up to a total of about 45 moles, preferably less than 20 moles? and even more preferably less than 15 moles ?, even more preferably less than 10 moles ?, and even more preferably less than 2 moles ?. Examples of these different optional diol units include aliphatic alkylene glycols having 3-12 carbon atoms and having the empirical formula H0-Q,? ^ N-0H, where n is an integer of 3-12, including branched diols such as 2, 2-dimethyl-l, 3-propanediol; cis or trans-1,4-cyclohexanedimethanol and mixtures of cis and trans isomers; triethylene glycol; 2, 2-bis [4- (2-hydroxyethoxy) phenyl] propane; 1, 1-bis [4- (2-hydroxyethoxy) phenyl] cydohexane; 9, 9-bis [4- (2-hydroxyethoxy) phenyl] fluorene; 1.4: 3, 6-dianhydromanitol; 1, 4: 3, 6-dianhydroiditol; and 1,4-anhydroerythritol. In a preferred embodiment, the number of terephthaloyl moieties in polymer is in the range of about 25 moles? to about 50 moles ?, more preferably about 40 moles? to about 50 moles, even more preferably about 45 moles? to approximately 50 moles? (moles of the total polymer). The polymer may also include amounts of one or more aromatic diacid portions such as, for example, those derived from isophthalic acid, 2,5-furanodicarboxylic acid, 2,5-thiophenedicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,7-acid. -naphthalenedicarboxylic acid, and 4,4'-benzoic acid, at combined levels of up to about 25 moles ?, preferably up to 10 moles ?, much more preferably up to about 5 moles? (moles of the total polymer). Of course, the totality of the percentages depends on the particular application desired. However, desirably, equimolar amounts of diacid monomer units and diol monomer units are present in the polymer. This equilibrium is desirable to obtain a high molecular weight. The polyester has an inherent viscosity, which is an indicator of molecular weight, of at least about 0.35 dl / g, measured in a 1% (w / v) solution of the polymer in o-chlorophenol at a temperature of 25 °. C. This inherent viscosity is sufficient for some applications, such as some optical articles and coatings. For CDs and DVDs, an inherent viscosity of at least about 0.4 dl / g to 0.5 dl / g is preferred. Higher inherent viscosities are required for many other applications (eg bottles, films, foils, molding resins). The conditions can be adjusted to obtain the desired inherent viscosities of up to at least about 0.5 dl / g and desirably greater than 0.65 dl / g. Further processing of the polyester can obtain inherent viscosities of 0.7, 0.8, 0.9, 1.0, 1.5, 2.0 dl / g, and even higher. Molecular weights are usually not measured directly. Instead, the inherent viscosity of the polymer in solution or the molten viscosity is used as an indicator of molecular weight. For the present polymers, the inherent viscosity is measured by the method previously described, with a molecular weight corresponding to an inherent viscosity of about 0.35 or greater which is sufficient for some uses. Higher molecular weights, corresponding to inherent viscosities of about 0.45 or greater, may be required for other applications. Generally, the inherent viscosity / molecular weight ratio can be adjusted to the linear equation: log (IV) = 0.5856 x log (Mw) - 2.9672 Inherent viscosities are a better indicator of molecular weight for sample comparisons and are used as the molecular weight indicator in the present. Some of the polymers of the invention can be manufactured by any of several methods. The product compositions vary to a certain extent depending on the method used, particularly in the amount of diethylene glycol portions that are present in the polymer. These methods include the reaction of diol monomers with chlorides. Terephthalic acid acid and any other acid that may be present. The reaction of terephthaloyl dichloride with isosorbide and ethylene glycol is easily carried out by combining the monomers in a solvent (for example toluene) in the presence of a base, such as pyridine, which neutralizes HCl as it is produced. This procedure is described in R. Storbeck et al., J. ADP !. Polymer Science, vol. 59, p. 1199-1202 (1996). Other well-known variations can also be used using terephthaloyl dichloride (for example interfacial polymerization or the monomers can simply be stirred together while heating). When the polymer is made using the acid chloride, the ratio of monomer units in the product polymer is about the same as the ratio of reactive monomers. Therefore, the ratio of monomers charged to the reactor is the same as the desired ratio in the product. A slight excess of diol or diacid or a trace amount of a monofunctional finishing group may be necessary to reduce the molecular weight of the polymer so that it has an inherent viscosity in the desired range. For example, an inherent viscosity in the range of about 0.40-0.50 dl / g is suitable for use in the manufacture of optical articles, such as substrates for CDs and DVDs and in lenses. Such adjustments in stoichiometry and conditions are easily realized by those skilled in the art. The conditions of the melt process of the present invention, particularly the amounts of monomers used, depend on the polymer composition desired. The amount of diol and diacid or dimethyl ester thereof is desirably chosen so that the final polymer product contains the desired amounts of the various monomer units, desirably with equimolar amounts of monomer units derived from the diols and from the diacids Due to the volatility of some of the monomers, including isosorbide, and depending on variables such as whether the reactor has been sealed (ie, under pressure), and the efficiency of the distillation columns used to synthesize the polymer, some of the monomers may be required to be included in excess at the beginning of the polymerization reaction and are removed by distillation as the reaction proceeds. This is particularly true for ethylene glycol and isosorbide. The exact amount of monomers to be charged in a particular reactor is easily determined by a person skilled in the art, but will often be in the following ranges. The excess ethylene glycol and isosorbide are desirably charged, and the excess ethylene glycol and isosorbide are removed by distillation or other evaporation medium-as the polymerization reaction proceeds. Terephthalic acid or dimethyl terephthalate is desirably included in an amount of about 50% to about 100 moles, more preferably 80 moles? to about 100 mole% of the diacid monomers that are charged, the remainder is optionally diacid monomers. Isosorbide is desirably loaded in an amount of about 0.25 mole% to about 150 mole? or more, compared to the total amount of diacid monomers. The use of diethylene glycol monomer is optional, and it is often made in situ. If diethylene glycol is added, is it charged in an amount of up to about 20 moles? of the total amount of the diacid monomers. Is ethylene glycol charged in an amount in the range of about 5 moles? to approximately 300 moles ?, desirably 20 moles? to approximately 300 moles? of the diacid monomers and optional additional diols are charged in an amount of up to about 100 moles? of the diacid monomers. The ranges given for the monomers used to make the polyester polymer are very wide due to the wide variation in monomer loss during polymerization, depending on the efficiency of the distillation columns and other kinds of recovery and recycling systems, and they are only an approximation. The exact amounts of monomers that are charged to a specific reactor to obtain a specific composition is easily determined by one skilled in the art. In the polymerization process, the monomers are combined, and gradually heated by mixing with a catalyst or a mixture of catalysts to a temperature in the range of about 260 ° C to about 300 ° C, desirably of 280 ° C to about 285 ° C. The exact conditions and catalysts depend on whether the diacids are polymerized as true acids or as dimethyl esters. The catalyst may be initially included with the reagents, or it may be added one or more times to the mixture, as it is heated. The catalysts used can be modified as the reaction progresses. Heating and stirring is continued for a sufficient time and at a temperature is sufficient, generally with removal with distillation of the excess reagents, to provide a molten polymer having a sufficiently high molecular weight to be suitable for manufacturing manufactured products. . Catalysts that may be used include Li, Ca, Mg, Mn, Zn, Pb, Sb, Sn, Ge, and Ti salts, such as salts and acetate oxides, including glycol adducts and Ti alkoxides. These are generally known in the art, and the specific catalyst or combination or sequence of catalysts used can be easily selected by one skilled in the art. The preferred catalyst and preferred conditions differ based on whether the diacid monomer is polymerized as the free diacid or as the dimethyl ester. The most preferred catalysts are those containing germanium and antimony. For applications where it is desirable to have an amorphous polymer, such as that which is used to make transparent optical articles, the amount of isosorbide portion is in the range of about 2% to about 30% on a molar basis, the portions of ethylene glycol are present in an amount of approximately 10? at about 48% on a molar basis, optionally other diols such as the 1,4-cyclohexanedimethanol portions are present in a maximum amount of about 45? on a molar basis, the diethylene glycol portions are present in an amount of from about 0.0% to about 5%, preferably from 0.25% to about 5? on a molar basis, the terephthaloyl moieties are present at a level of approximately 25? at approximately 50? and other optional diacid portions, such as 2,6-naphthalenedicarboxylic acid, isophthalic acid, 4,4'-benzoic acid and mixtures thereof, are present in amounts up to a total of about 25? on a molar basis. Some of these compositions (ie, those that have isosorbide at concentrations less than about 12?) Are semicrystalline if they are cooled slowly from the melt or if they anneal above their vitreous transition temperatures, but are amorphous if cooled rapidly of the melt. In general, the compositions which can be semicrystalline are slower to crystallize than the poly (ethylene terephthalate) compositions, so that it is easier to make transparent articles that remain transparent using crystallizable copolymers even though they may be exposed to low conditions. which can crystallize. The melt polymerization process of the present invention is desirably carried out either using dimethyl esters (for example dimethyl terephthalate) as reactants, or using the free diacid as a reagent. Each process has its own preferred catalyst and its preferred conditions. These are generally described in the following. These are analogues which are well known processes for the preparation of poly (ethylene terephthalate). The utility of these methods for obtaining a high molecular weight polymer is surprising in view of the descriptions by others who have worked with isosorbide polyesters and in view of what is generally expected to be that the secondary diols have low reactivities and the esters of secondary alcohols have reduced thermal stability. These two processes are a little different and are described later.

PROCESS FOR DIMETILO TEREFTALATE It is this process, which is carried out in two stages, using terephthalic acid and the optional diacid monomers, if present, as their dimethyl ester derivatives. In smaller quantities, for example 1-2? by weight, free diacids can also be added. The diols (for example ethylene glycol and isosorbide) are mixed with dimethyl ester of the aromatic diacid (for example dimethyl terephthalate) in the presence of an ester exchange catalyst, which causes the exchange of the ethylene glycol by the methyl group of the esters of dimethyl through a transesterification reaction. This results in the formation of methanol, which is removed by distillation from the reaction flask, and bis (2-hydroxyethyl terephthalate). Due to the stoichiometry of this reaction, a little more than 2 moles of ethylene glycol are desirably added as reactants for the ester exchange reaction. Catalysts that carry out ester exchange include salts (usually acetates) of the following metals: Li, Ca, Mg, Mn, Zn, Pb and combinations thereof, Ti (OR) 4, wherein R is a group alkyl having 2-12 carbon atoms, and PbO. The catalyst components are generally included in an amount of about 10 ppm to about 100 ppm. Preferred catalysts for ester exchange include Mn (OAc) 2, Co (OAc) 2 and Zn (OAc) 2, where OAc is the abbreviation for acetate, and combinations thereof. The polycondensation catalyst in the second stage of the reaction, preferably Sb (III) oxide can now be added or at the start of polycondensation. A catalyst that has been used with particularly good success is based on salts of Mn (II) and Co (II) at levels of about 50 to about 100 ppm, each. These are used in the form of Mn (II) tetrahydrate acetate and Co (II) acetate tetrahydrate, although other salts of the same metals can also be used. Ester exchange is desirably carried out by heating and stirring the reagent mixture under an inert atmosphere (eg nitrogen) at atmospheric pressure from room temperature to a temperature high enough to induce ester exchange (approximately 150 ° C). The methanol is formed as a by-product and is distilled off from the reactor. The reaction is gradually heated to about 250 ° C until the production of methanol ceases. The end of methanol production can be recognized by a decrease in the upper temperature of the reaction vessel. A small amount of an additive having a boiling point of 170-240 ° C can be added to the ester exchange to aid in heat transfer within the reaction medium and to help retain volatile components in the container that can Sublimate to the packed column. The additive must be inert and not react with alcohols or dimethyl terephthalate at temperatures below 300 ° C. Preferably, the additive should have a boiling point greater than 170 ° C, more preferably within the range of 170 ° C to 240 ° C, and is used in an amount between about 0.05 and 10? by weight, more preferably between about 0.25 and 1% by weight of the reaction mixture. A preferred additive is tetrahydronaphthalene. Other examples include diphenylether, diphenylsulfone and benzophenone. Other such solvents are described in U.S. Patent 4,294,956, the content of which is incorporated herein by reference. The second stage of the reaction is initiated by adding a polycondensation catalyst and a sequestering agent for the transesterification catalyst. The polyphosphoric acid is an example of a sequestering agent that is normally added in an amount of about 10 to 100 ppm phosphorus per g of dimethyl terephthalate. An example of a polycondensation catalyst is antimony (III) oxide, which can be used at a concentration of 100 to approximately 400 ppm. The polycondensation reaction is typically carried out at a temperature of about 250 ° C to 285 ° C. During this time, ethylene glycol is distilled off from the reaction due to the condensation of bis (2-hydroxyethyl) terephthalate to form the polymer and a by-product of ethylene glycol, which is collected as a distillate. The polycondensation reaction described above is preferably carried out under vacuum, which can be applied while the reactor is heated to the polycondensation reaction temperature after polyphosphoric acid and Sb (III) oxide have been added. Alternatively, vacuum may be applied after the polycondensation reaction temperature reaches 280 ° C-285 ° C. In any case, the reaction is accelerated by the application of vacuum. The vacuum heating is continued until the molten polymer reaches the desired molecular weight, usually recognized by an increase in the melted viscosity to a predetermined level. This is observed as an increase in the torque required for the agitation motor to maintain agitation. An inherent viscosity of at least 0.5 dl / g, and generally up to about 0.65 dl / g or more can be obtained by this melt polymerization process without additional efforts at increasing molecular weights.

TEREFTAL ACID PROCESS The process of terephthalic acid similar to the process of dimethyl terephthalate except that the initial esterification reaction leads to bis (2-hydroxyethylterephthalate) and other low molecular weight esters are carried out at a slightly higher pressure (autogenous pressure, approximately 172 to 345 kPa (25-50 psi)). Instead of a double excess of diols, a smaller excess is used (approximately 10% to approximately 60%) of diols (ethylene glycol, isosorbide and other diols, if any). The intermediate esterification product is a mixture of oligomers, since sufficient diol is not present to generate a diester of terephthalic acid. The catalyst is also different. There is no need to add catalyst in the esterification reaction. A polycondensation catalyst (for example salts of Sb (III) or Ti (IV)) are still desirable to obtain a high molecular weight polymer. The catalyst that is needed to obtain a high molecular weight can be added after the esterification reaction, or it can be conveniently charged with the reactants at the beginning of the reaction. Catalysts which are useful for making the high molecular weight polymer directly from terephthalic acid and the diols include acetate and other salts of Co (II) alkanoate and Sb (III), Sb (III) oxide and Ge (IV) , and Ti (0R) 4 (wherein R is an alkyl group having 2 to 12 carbon atoms). Oxides solubilized with glycol from these metal salts can also be used. The use of this and other catalysts in polyester preparations is well known in the art. The reaction can be carried out in discontinuous steps, but this is not necessary. In large-scale practice, it can be carried out in stages to the extent that reagents and intermediates are pumped from the reactor into a reactor at increasing temperatures. In a batch process, the reactants and the catalyst can be charged to the reactor at room temperature and then gradually heated to about 285 ° C as the polymer is produced. The pressure is vented in the range of about 200 ° C to about 250 ° C, and vacuum is then applied in a desirable manner. The esterification to form bis (2-hydroxyethylterephthalate) esters and the oligomers is brought to elevated temperatures (between room temperature and about 220 ° C to 265 ° C under autogenous pressure), and a polymer is processed at temperatures in the range of approximately 275 ° C to approximately 285 ° C under high vacuum (less than 10 Torr, preferably less than 1 Torr). The vacuum is necessary to remove residual ethylene glycol, isosorbide and water vapor from the reaction to increase molecular weight. A polymer having an inherent viscosity of at least 0.5 dl / g, and generally up to about 0.65 dl / g, can be obtained by a direct polymerization process, without subsequent solid state polymerization. The progress of the polymerization can be monitored by the melt viscosity, which is observed facially by the torque required to maintain the stirring of the molten polymer.

POLYMERIZATION IN SOLID STATE For certain ranges of composition, the molecular weight can be further increased by polymerization in the solid state. However, in general, solid state polymerization is not needed for most optical articles because a sufficient molecular weight is obtained in the melt polymerization reaction. Solid state polymerization, if desired, is described in application serial number 09/064, 844 (attorney's file No. 032358-001), the content of which is incorporated herein by reference.

USE OF POLYMERS FOR THE MANUFACTURE OF OPTICAL ARTICLES The transparent and amorphous polymers produced by the above process can be mixed with other additives before being molded into optical articles. One or more additives may be included for such purposes in order to improve thermal stability, inhibit oxidation, improve polymer flow characteristics, add color to the polymer and improve the mold release properties of the polymer. The additives that perform these functions are well known in the art. In compositions that have been made and molded into discs, ULTRAN0XMR 628, IRGAN0XMR 1010 (Ciba Geigy), IRGAFOSMR 168 (Ciba Geigy, Ardsler, NY) and some combinations thereof have been successfully used as heat stabilizers. ACROWAXMR (from Lonza) Hoechst Wax C (from Hoechst AG, Frankfurt, Germany) and zinc stearate have been added as flow improvers / mold release agents. Flow improvers also reduce the opalescence of molded articles. These can be added at concentrations of about 0.1% to 0.5% by weight. Other alternative additives and amounts can be easily chosen by those skilled in the art. The polymeric materials are formed into optical articles and intermediate products for manufacturing optical articles by any of the commonly used methods for forming polymers. These include injection molding; compression molding, extrusion through a die to make a film, fiber, bar or the like; calendered; Recorded; stamping and injection / compression molding. The articles made by these methods can be used for such applications as substrates for CD and DVD, CD and DVD, lenses, Fresnel lenses, instrument and cover panel windows, prismatic reflectors, films and thick and thin films, optical fibers and similar. The preferred method of shaping the polymers is by injection or compression molding or a combination of injection / compression molding. The preferred optical articles made from these polymers are CD and DVD, the substrates from which CDs and DVDs are made, as well as lenses, including Fresnel lenses. The polymer that is used for injection molding of these preferred articles preferably has an inherent viscosity of about 0.40 to about 0.50 dl / g, and more preferably about 0.40 to about 0.45 dl / g, wherein the inherent viscosity is measured in a solution to 1? (weight / volume) of the polymer in o-chlorophenol at 25 ° C. This relatively low inherent viscosity is desirable because the polymer has a sufficiently low melt viscosity so that it can be injection molded rapidly, with a rapid relaxation of the birefringence and mechanical stresses that occur during molding before the polymer solidify. These result in a molded article that has low birefringence. An important property of this particular family of polymers is that the polymers have good mechanical and thermal properties, even though the molecular weight is reduced for ease of molding.

This invention is further illustrated by the following non-limiting examples.

EXAMPLE 1 .68 kg of dimethyl terephthalate, 5.79 kg of isosorbide, 4.88 kg of ethylene glycol, 4.76 g of manganese acetate (II) are placed in a stirred reactor, stainless steel, under nitrogen purge at atmospheric pressure. The reactor is equipped with a filler distillation column. The composition of the monomer corresponds to a molar ratio of dimethyl terephthalate: ethylene glycol: isosorbide of 1: 1.43: 0.72. The reactor is heated to 230 ° C in the next three hours, to 240 during the next hour and to 265 during the next hour. During this time, a distillate consisting mainly of methanol is collected from the packed column. After the temperature reaches 284 ° C, polyphosphoric acid is added to the reactor. The amount of polyphosphoric acid is equivalent to 402 mg of phosphorus. 4.66 g of germanium oxide (IV) catalyst is added as a solution in ethylene glycol (0.100N of Ge02 in ethylene glycol). The pressure inside the reactor is now reduced to 1 ml of mercury for a period of 2 hours. The reaction mixture is kept under vacuum for an additional 3 hours, and an additional distillation fraction is collected while the temperature is increased to 285 ° C. Subsequently, the reaction product, a viscous resin, is extruded in a water bath, cut into granules and dried in an oven. The resin has a glass transition temperature of 106 ° C and an inherent viscosity of 0.43 dl / g (measured at 25 ° C in an orthochlorophenol solution of 1? (weight / volume)). The monomeric composition of the polymer is measured by NMR as 50.1? of terephthalate, 33.5? of ethylene glycol residue, 2.6? of diethylene glycol residue and 12.9? of isosorbide residue, expressed as moles? of the polymer.

EXAMPLE 2 7.48 kg of purified terephthalic acid, 3.55 kg of isosorbide and 1.70 kg of ethylene glycol are placed in a stirring stainless steel reactor, preheated to 70 ° C under a nitrogen purge at atmospheric pressure. The reactor is equipped with a packed distillation column. The composition of the monomer corresponds to the molar ratio of the terephthalic acid: ethylene glycol: isosorbide of 1: 0.61: 0.54. The reactor is heated to 285 ° C in the next 3 hours and the reaction mixture is maintained under a positive pressure of 345-414 kPa (50-60 psi). During this time, a water distillate is mainly collected from the packed column. After the melting temperature reaches at least 275 ° C, and terephthalic acid is essentially consumed, determined by clearing the reaction mixture, the pressure is released and 3.77 g of germanium oxide catalyst is added (IV ) to a solution of ethylene glycol (O.IOON of Ge02 ethylene glycol.) The reaction mixture is stirred for an additional 20 minutes.The pressure in the reactor is reduced to 1-2 mm of mercury over a period of 1 hour and a fraction is collected. Further, the reaction product, a viscous resin, is extruded in a water bath, cut into granules and dried in an oven.The resin has a vitreous transition temperature of 116 ° C and an inherent viscosity. 0.43 dl / g (measured at 25 ° C in a 1% (weight / volume) orthochlorophenol solution.) The monomeric composition of the polymer is measured by NMR as 49.5% terephthalate, 30.3% ethylene glycol residue, 2.0% Diethylene glycol residue cabbage and 18.2% isosorbide residue, expressed as one mole? of the polymer.

EXAMPLE 3 The polymer of example 1 is injection molded using an Arburg injection molding machine (Arburg Maschinen Fabrik, Lossburg, Germany), into standard tension bars to measure the tensile and bending properties and is also injection molded into disks. The melting temperature is 270 ° C, and the temperature of the mold is 30 ° C. The properties of the polymer and the molded products are presented in Table 1.

EXAMPLE 4 Compact disks are molded from the described polymer and made in Example 1 using a Uniline 3000 replication line from First Light Technology, Inc. (Saco, Maine). The line consists of an injection molding machine (Netstal Discjet 600, Nafel, Switzerland), a CD mold (ICT Axxicon, Eindhoven, the Netherlands), a metallizing unit and coating and printing stations. The CDs are molded with a barrel temperature of 300 ° C, a nozzle temperature of 310 ° C, a mold temperature of 40 ° C, an injection time of 0.4 seconds, a cooling time of 1.8 seconds and a time of total cycle of 5 seconds. The measured optical and electronic parameters of the molded and metallized discs are presented in Table 2. Table 2 presents measured values and the specifications used in the industry. The specifications in table 2 are written according to the "free red" that is established in the compact disc digital audio description systems (N.V. Phillips, Eindhoven, The Netherlands and Sony Corporation, Japan). The data in table 2 are within these specifications or are below the upper allowable limit. The measurements are standard in the industry and are summarized below.

Delay is birefringence multiplied by the CD substrate thickness. Birefringence is the difference in the refractive indices along the radial and tangential directions, respectively. The optical delay is measured using a birefringence analyzer. Pitting depth is measured in relation to the height of the toms in the stamper used to mold the discs. It is measured using an atomic force microscope (AFM, Digital Instruments, Santa Barbara, CA). The rest of the parameters in table 2 is measured by a CDCATS SA3 analyzer (Audio Development Infor ationteknik, Sweden). Deflation refers to the radial deflection of the light beam due to bending and bending of the disk. The pulled thrust is a measure of how easy the impeller can start on the track as it follows the signal (high frequency). HF signal 13 is a measure of the decoding problems. (High frequency) HF 111 is similar to HFI3. Reflectivity is the level of light reflected from the stings. The block error rate (BLER) is a measure of pitting blocks that can not be read or corrected.

It should be understood that the embodiments described in the foregoing are illustrative only and that modifications may occur thereto to one skilled in the art. Accordingly, this invention is not considered to be limited to the embodiments described herein.

Table 1. Properties of optical polymers - 4? - 4á - Table 2. Measured properties of molded CDs The optical articles of the present invention can also be made with the polyesters described in copending application 09/064, 720 [file of lawyer no. 032358-008], and the polyester combinations described in copending application 09/064, 826 [attorney's file no. 032358-005], the content of each of which is incorporated herein by reference.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention

Claims (22)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. An optical article, characterized in that it comprises a transparent polymer which comprises portions of terephthaloyl, optionally, other portions of aromatic diacid; portions of ethylene glycol; portions of isosorbide and, optionally, one or more additional diol portions, wherein the polymer has an inherent viscosity of at least about 0.35 dl / g when measured as a solution to 1? (weight / volume) in o-chlorophenol at a temperature of 25 ° C.

2. The optical article according to claim 1, characterized in that the polymer has an inherent viscosity in the range of about 0.4 to about 0.5 dl / g.

3. The optical article according to claim 1, characterized in that the optical article is a compact disc, a digital versatile disc, a substrate for a compact disc or a digital versatile disc, a lens, an instrument panel window or cover, a prismatic reflector, a film, foil or optical fiber.

4. The optical article according to claim 1, characterized in that the terephthaloyl portions are present in an amount of about 25 moles? to approximately 50 moles? of the polymer, wherein the isosorbide portions are present in an amount from about 0.25 moles? to approximately 40 moles? of the polymer, wherein the polymer optionally additionally comprises portions of aromatic diacid other than the terephthaloyl portions in the range of 0 to about 10 moles? of the polymer, portions of ethylene glycol in an amount of up to about 49.75 moles? of the polymer and portions of additional diols in an amount of up to about 15 moles? of the polymer.

5. The optical article according to claim 4, characterized in that the additional aromatic diacid portions are derived from isophthalic acid, 2,5-furanodicarboxylic acid, 2,5-thiophenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-acid. -naphthalenedicarboxylic acid, and 4,4'-benzoic acid, or mixtures thereof.

6. The optical article according to claim 4, characterized in that the other diol portions are derived from aliphatic alkylene glycols or branched diols having 3-12 carbon atoms and having the empirical formula, H0-CnH2n-0H, wherein n is an integer of 3-12; cis or trans-1,4-cyclohexanedimethanol or mixtures of the cis and trans isomers; diethylene glycol; triethylene glycol; 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane; 1, 1-bis [4- (2-hydroxyethoxy) phenyl] cydohexane; 9, 9-bis [4- (2-hydroxyethoxy) phenyl] -fluorene; 1.4: 3, 6-dianhydromanitol; 1, 4: 3, 6-dianhydroiditol; and 1,4-anhydroerythritol or mixtures thereof.

7. The optical article according to claim 4, characterized in that the terephthaloyl moieties are present in an amount of about 45 moles? to approximately 50 moles? of the polymer, the isosorbide portions are present in an amount of about 0.25 moles? to approximately 20 moles? of the polymer, the ethylene glycol portions are present in an amount of about 5 moles? up to approximately 48 moles? of the polymer, additional diacid portions are present in an amount from 0 to about 5 moles? of the polymer, and additional diol portions are present in an amount from 0 to about 2 moles? of the polymer.

8. The optical article according to claim 7, characterized in that the optical article is a compact disk, a digital versatile disk, a substrate for a compact disk or digital versatile disk.

9. The optical article according to claim 8, characterized in that the polymer has an inherent viscosity in the range of about 0.4 to about 0.5 dl / g.

10. A method for making an optical article, characterized in that it comprises the steps of: (a) providing a polymer which comprises portions of terephthaloyl, optionally additional aromatic diacid portions; portions of ethylene glycol; portions of isosorbide; and, optionally, one or more additional diol portions, wherein the polymer has an inherent viscosity of at least about 0.35 dl / g measured in a 1% (w / v) solution in o-chlorophenol at 25 ° C; Y (b) forming the polymer into an optical article or a substrate that is used in an optical article.

11. The method in accordance with the claim 10, characterized in that the shaping comprises injection molding, compression molding, calendering, engraving, stamping, injection molding / compression or extrusion.

12. The method in accordance with the claim 11, characterized in that the extrusion is through a die that provides fibers, films, sheets or bars.

13. The method in accordance with the claim 10, characterized in that the polymer has an inherent viscosity in the range of about 0.4 to about 0.5 dl / g.

14. The method in accordance with the claim 10, characterized in that the polymer is formed into a compact disc, a digital versatile disc, substrate for a compact disc or digital versatile disc, lens, instrument panel or cover window, prismatic reflector, or optical fiber.

15. The method according to claim 10, characterized in that the terephthaloyl moieties are present in an amount of about 25 moles? up to approximately 50 moles? of the polymer, wherein the isosorbide portions are present in an amount from about 0.25 moles? up to about 40 moles? of the polymer, the other aromatic diacid portions are present in an amount of from about 0 to about 10 moles ?, the ethylene glycol portions are present in an amount of about 49.75 moles? of the polymer, and the other portions of diols are present in an amount of up to about 15 moles? of the polymer.

16. The method in accordance with the claim 15, characterized in that the additional aromatic diacid portions are derived from isophthalic acid, 2,5-furanodicarboxylic acid, 2,5-thiophenedicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, and 4,4 'acid. -bibenzoic, or mixtures thereof.

17. The method according to claim 15, characterized in that the other diol portions are derived from aliphatic alkylene glycols or branched diols having 3-12 carbon atoms and having the empirical formula, HO-CnH2n-OH, wherein n is a integer of 3-12; cis or trans-1,4-cyclohexanedimethanol or mixtures of the cis and trans isomers; triethylene glycol; 2, 2-bis [4- (2-hydroxyethoxy) phenyl] propane; 1, 1-bis [4- (2-hydroxyethoxy) phenyl-cyclohexane; 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene; 1.4: 3, 6-dianhydromanitol; 1, 4: 3, 6-dianhydroiditol; and 1,4-anhydroerythritol or mixtures thereof.

18. The method in accordance with the claim 15, characterized in that the terephthaloyl moieties are present in an amount of about 45 moles? up to approximately 50 moles? of the polymer, the isosorbide portions are present in an amount of about 0.25 moles? up to about 20 moles? of the polymer, the ethylene glycol portions are present in an amount of about 5 moles? up to approximately 48 moles? of the polymer, the other additional diacid portions are present in an amount from 0 to about 5 moles? of the polymer, and the other additional diol portions are present in an amount from 0 to about 2 moles? of the polymer.

19. The method according to claim 18, characterized in that the polymer is formed into a compact disk, digital versatile disk, or substrate for a compact disk or digital versatile disk.

20. The method according to claim 19, characterized in that the polymer has an inherent viscosity in the range of about 0.4 to about 0.5 dl / g.

21. The method according to claim 18, characterized in that it further comprises molding the polymer by injection molding, compression molding or combined injection / compression molding to provide a disc having punctures in a compact disc format suitable for reading with a laser; cover the disc with a reflective coating; and coating the disk with a protective coating to provide a compact disk.

22. The method according to claim 18, characterized in that it comprises molding the polymer by injection molding, compression molding or combined injection / compression molding to provide a disc having punctures in a digital versatile disc format suitable for reading with a laser; cover the disc with a reflective coating; add additional reflective layers, semi-reflective layers before or both reflective layers and semireflect before to provide a digital versatile disk.