MXPA01003566A - Aromatic acid monomers, polymers, products and processes for their manufacture - Google Patents

Abstract

Processes for producing aromatic monomers useful for forming polyesters are disclosed. Cost effective steps employed in the processes permit small amounts of process-related materials typically removed from monomer to remain in an aromatic monomer product. In many cases, the presence of the process-related materials left in the monomer product by the cost effective process steps can enhance the performance of the monomer in certain applications. Aromatic monomer products and polymers produced therefrom having these advantages also are disclosed, as well as products such as pasteurizable bottles made from these polymers.

Description

-1 MONOMERS OF AROMATIC ACID, POLYMERS, PRODUCTS AND PROCESSES FOR ITS MANUFACTURE FIELD OF, THE INVENTION 'The invention is generally concerned with polymers formed from aromatic acids. More particularly, the invention is concerned with aromatic acid monomers which contain small amounts of materials which may provide unexpected advantages during the polymerization or copolymerization of those acid monomers, as well as processes for manufacturing such mono-ions of aromatic acids and polymers.

BACKGROUND OF THE INVENTION The manufacture of useful aromatic acids such as z. ? "Monomers" is commonly a complex multi-stage process, for example, 2,6-naphthalenedicarboxylic acid 2,6-NDA) can be manufactured by a five-step synthesis process that includes the steps of reacting or - xylene and butadiene in an alkenylation reaction to produce 5-ortho-tolylpentene, cyclization of 5-ortho-tolylpentene to form 1-, 5-d-methyltetraline (1,5-DMT), dehydrogenation of 1,5-DMT to produce 1,5-dimethylnaphthalene (1,5-DMN), isomerization of 1,5-DMN to produce 2,6-dimethenaphthalene (2,6-DMN) and oxidation of 2,6-DMN to produce 2, 6-NDA.

Ref: 128710 The raw NDA produced by such a process will contain a wide variety of what is believed to be the undesirable material related to the process. Many of these materials will be 2,6-NDA isomers or mono- or tri-functional reaction products. Other undesirable process related materials contained in the crude NDA will be reactive such as catalytic metals carried through the various reaction stages and colorless bodies formed during the reaction steps. As used herein, the term "material related to the process" means any material that is formed or added at any stage of the process leading to the manufacture of the aromatic acid monomer product in which they are included, but are not limited to catalysts, products of side reactions, undesirable oxidation products, undesirable isomers and the like. It is believed that in the preparation of polyesters from monomers such as NDA, the purity of the monomer is critical to satisfactorily obtain high molecular weight polymers and a sufficiently fast kinetic polymerization rate. For this reason, polymer manufacturers commonly require that monomer impurities such as monofunctional and trifunctional glycols and carboxylic acids be minimized or eliminated from the monomers to be used in the polymerization reactions. For example, it is expected that terephthalic acid and isophthalic acid commonly contain less than 200 parts per million or less in total weight of the monocarboxylic and tricarboxylic acids. Similarly, it is expected that the ethylene glycol used in polymerization reactions usually does not contain detectable impurities. It is thought that tricarboxylic acids are undesirable because such trifunctional compounds can cause undesirable crosslinking of polymer chains. It is reported that such crosslinking contributes to low crystallization rates and polymer brittleness, both of which are undesirable characteristics in many applications. Additionally, when the crosslinking becomes substantial a "gel point" is reached. At this point, the polymer can not be polymerized in the molten state or in the molten state and is no longer considered a thermoplastic material. • It is believed that monocarboxylic acids and other monofunctional materials are undesirable components in monomers because they act as "chain lids" that inhibit the development of molecular weight and because they decrease the reaction kinetics. If the concentration of such materials is too high, the polymerization rate can become zero due to the termination of otherwise reactive end groups.

It is thought that color bodies of various types are undesirable in monomers. The presence of colored bodies in the monomer can result in a substantially greater color in a polymer than would likely appear from apparently small amounts of visible color in a monomer, thus still making minute amounts of colorless bodies in the undesirable monomers. As used herein, the term "colored bodies" refers to any carboxylic acid containing material related to the process present in a monomer or polymer that may contribute to the presence of color in the monomer or polymer if present in the sufficient quantity. It is thought that metals such as entrained catalytic metals are undesirable components in the monomers. For example, it is believed that the entrained cobalt and manganese oxidation catalyst are undesirable monomer impurities because they are expected to affect the polymerization rate and color of the polymer in an unpredictable manner. It is thought that such metals also sometimes affect the amount of color visible in a monomer or polymer. Because it is believed that the presence in the monomer of undesirable process related materials such as by-products, reagents and impurities as color bodies can result in a lower polymer product, a substantially large effort is devoted to improving the purity of monomers such as 2,6-NDA to provide a product quality that is considered acceptable by customers. For example, purified aromatic acids have been produced from crude aromatic acids upon suspension of the effluent from a crude aromatic acid oxidation process, passing the slurry or slurry through a plurality of heaters until the products of The reaction is dissolved, passing the resulting solution over a purification catalyst and then crystallizing a purified product. Such a process requires substantial time and energy beyond that expended to produce crude aromatic acid and therefore substantially increases the cost of the monomer. Alternatively, the high purity monomer can be manufactured from a relatively high purity feedstock, such a process in which relatively pure 2,6-naphthalenedicarboxylate (2,6-NDC) is hydrolyzed to form relatively pure NDA. This process is also cost intensive due to the complexity and expense of producing the relatively pure NDC feedstock material.

What is needed is an effective cost way to produce aromatic acids such as NDA that are suitable for use in polymer applications.

BRIEF DESCRIPTION OF THE INVENTION Surprisingly, it has been found that the presence of certain levels of materials related to the process in aromatic acid monomers can result in monomers that also function or better than aromatic acid monomers of higher purity when used. in many polymer applications. In some applications, the presence of certain levels of catalytic metals can result in faster polycondensation and polymerization reactions in the solid state, thereby improving the economics of these polymerization reactions without affecting the desired properties of the polymer product. In other applications, the presence of certain trifunctional materials in the aromatic acid monomer product provides the branching of polymer chains, thereby providing an increased melt strength which is useful when articles are molded from the polymer. In still other applications, the presence of certain levels of metallic impurities and color bodies provides an aromatic acid monomer having a brownish molding that is useful in particular end uses., which include but are not limited to the packaging of beverages such as beer in coffee colored polymeric bottles. While in some cases the above aromatic acid monomers could be produced directly as solids separated from the product of an oxidation reaction, commonly the aromatic monomer product according to the present invention will be produced by a relatively simple post-processing of materials oxidized aromatic feedstocks, such as by suspending or washing crude aromatic acid in an appropriate solvent under the appropriate process conditions. The monomeric product manufactured in this way can be both less expensive and advantageous in certain end uses.

DETAILED DESCRIPTION OF THE INVENTION The following detailed description of preferred embodiments of the invention focuses on the advantages of the invention with respect to the preparation of the 2,6-naphthalene dicarboxylic acid monomer product and polymers made therefrom. As will be discussed later in more detail, it is believed that the advantages of the invention are also useful in relation to other aromatic acid monomers such as terephthalic acid, isophthalic acid and other isomers of naphthalene dicarboxylic acids. As indicated above, 2,6-naphthalenedicarboxylic acid (2,6-NDA) can be manufactured by a five step synthesis process which includes the steps of reacting o-xylene and butadiene and an alkenylation reaction to produce -orto-tolylpentene, cyclization of 5-ortho-tolylpentene to form 1,5-dimetitetralin (1,5-DMT), dehydrogenation of 1,5-DMT to produce 1,5-dimethylnaphthalene (1,5-DMN), isomerization of 1,5-DMN to produce 2,6-dimethylnaphthalene (2,6-DMN) and oxidation of 2,6-DMN to produce 2,6-NDA. The aromatic feedstocks such as the 2,6-DMN oxidized in this process preferably contain at least 97 mol% of the feed material to be oxidized to the acid, calculated as one mole percent of the whole aromatic material in the raw material of food. The crude 2,6-NDA produced by the above process preferably contains at least 93 mol% acid monomer and is commonly expected to contain unacceptable levels of one or more of the following materials: trifunctional materials, l-bromo- 2, 6-NDA, 2-naphthoic acid, 6-formyl-2-naphthoic acid, cobalt, manganese, bromine, iron and various colored bodies. It has been found that frequently it is not dangerous and in many cases it is advantageous to allow certain levels of metals, trifunctional compounds and color bodies to be present in the 2,6-NDA monomer product used in the polymerization reactions. In many cases, these levels of acceptable and advantageous materials can be obtained by the relatively simple processing of the oxidation product of 2,6-DMN, thereby eliminating the need for expensive purification steps such as recrystallization. Acceptable and preferred levels of the above materials consistent with the invention are listed in Table 1 below. The ppm ranges listed refer to the ppm by weight of the material present in the NDA monomer product.

Table 1 Material Acceptable level Preferred level trifunctional 50 to 10,000 150 to 8,500 monofunctional 50 to 5,000 150 to 3,500 metals (Co + Mn) 50 to 10,000 500 to 2,000 bodies of color 50 to 500 50 to 250 The NDA monomer having one or more of the above materials in concentrations according to the invention can easily be produced by, for example, suspending the crude NDA oxidation product to separate a fraction of such materials, as long as allows a desirable or at least non-detrimental portion of such materials to remain in the monomer. As used herein, the term "suspension" refers to any process that employs a solvent to wash or disperse a crude oxidation product, but specifically excludes any process that dissolves more than about 10 mol% of a desired aromatic monomer present in crude oxidation products, such as a recrystallization step. Other examples of "suspension" processes according to the invention include the use of higher solvent volumes in the reactor in which the aromatic feedstock is oxidized to render the materials more soluble in the process, reducing a both by this the levels present in the product, adding or increasing the volume of solvent in the crystallizer train of the oxidation process to reduce the presence of material related to the process by dilution and the use of filtration with a solvent wash to reduce the level of materials related to the process remaining in the monomer product.

For example, the crude 2,6-naphthalenedicarboxylic acid can be recovered directly from the mother liquor (concentrated solution) of oxidation of 2,6-DMN. Then the crude 2,6-NDA can be redispersed or resuspended in an appropriate solvent such as water, a low molecular weight carboxylic acid or a mixture of water and a low molecular weight carboxylic acid at a weight ratio of about 0.1 to about 1 part of 2,6-naphthalenedicarboxylic acid per part of solvent. Preferred process conditions for the suspension process include temperatures of 60 to 125 ° C, a temperature of 75 to 110 ° C is more preferred and pressures of about 0.5 to 3 atmospheres, pressures of 1 to 2 atmospheres are more preferred. The proportions of solvent acid to water can range from 100% acid to 100% water, the proportion in parts of acid to water preferred is about 90:10 to 50:50, the most preferred ranges are about 80 parts of acid and 20 parts of water. Preferably, at least a portion of the solvent used to redisperse or resuspend 2,6-naphthalene dicarboxylic acid in this manner is a process stream or process derived stream such as condensate from the vapor output of the oxidation reaction mixture. . In this case, the solvent comprising water and acid such as acetic acid can be returned, at least in part, to the oxidation reactor. Alternatively, the solvent can be distilled to recover the low molecular weight carboxylic acid for recycling to the oxidation reactor. The solvents may contain other process materials that will not substantially affect the suspension process or properties of the monomer product, such as alcohols or acetates generated in the process. However, such process streams must contain little or none of the materials related to the process that seek to be minimized in the suspension process. The above suspension step provides a relatively purer 2, 6-naphthalenedicarboxylic acid. In many cases, such a 2,6-NDA monomer product, according to the invention will be appropriate or preferred for certain applications with respect to a monomer product produced from a more complex process having additional purification steps. After this suspension step, the 2,6-naphthalenedicarboxylic acid can be separated from the solvent by any method or methods known in the art for dividing or separating a solid from a liquid phase such as for example centrifugation, filtration or settling. Of particular interest in the resuspended NDA are concentrations of catalytic metals such as cobalt and manganese, the proportion of cobalt and manganese metals, the level of multifunctional aromatics and the level of colored impurities. The levels and proportions of catalytic metals are important because they will affect the polymerization rate of the monomer and because its presence may in some cases influence the color of the final polymer. For NDA applications, the total amount of Co and Mn present in the resuspended material should not be more than approximately 10,000 parts per million by weight of the resuspended product, from 500 to 2,000 parts per million is preferred, and from 1,000 to 1,500 parts by million is more preferred. The molar ratio Co to Mn can range from 5: 1 to 0.2: 1, the preferred proportions are from 4: 1 to 0.25: 1 and the most preferred proportions are 3: 1 and 0.5: 1. The levels of multifunctional materials are important when the polymer to be produced from the aromatic monomer requires an additional melting force. For NDA applications, trifunctional naphthalenic portions are the most likely species, 1,2,6-, 1,3,7- and 2,3,6-naphthalene tricarboxylic acids predominate in the mixture. Preferably, these trifunctional species will be present in the resuspended NDA in an amount of between 50 and about 10, 000 parts per million by weight, preferably between approximately 200 and 9,000 ppm by weight and more preferably between approximately 150 and 8,500 ppm by weight. When other aromatic monomers such as PTA are the subject of the invention, trifunctional acids such as 1,2,3-, 1,2,4- and 1, 3, 5-benzenetricarboxylic acids and mixtures thereof are the trifunctional species more probable and may be present in the ranges previously received for naphthalene trifunctional species. Mixtures of any and all of the above trifunctional impurities can of course be present according to the invention and impurities having a functionality greater than 3 can be advantageously used according to the invention, as used herein, the term "trifunctional material" "means any material related to the process having three functional groups capable of reacting with a glycol number under polymerization conditions. The term "multifunctional material" means any such material with a functionality of three or more. The color of polyester is a very important performance requirement in certain applications, while in other applications, color is not important. Sometimes, a color such as coffee is required for certain packaging applications. The brown color is commonly obtained between the addition of dyes that are usually high molecular weight organic compounds. The dyes are undesirable because they can impair the properties of polyester, especially the barrier permeation to gases such as oxygen and carbon dioxide. Additionally, dyes are expensive and may be undesirable from environmental recycling points of view. Thus, the color groups present in an aromatic acid monomer may be useful for inducing a color such as coffee or amber to the polymers formed subsequently. Color bodies useful according to the invention include benzocoumarin, pentaquinone, pentacene and fluorenone structures containing carboxylic acid functions. Typically, these color bodies should be present in an amount of between about 50 and about 500 parts per million by weight, more preferably between about 50 and 250 ppm and more preferably present at a level of about 150 ppm. The suspended NDA according to the invention may also contain monofunctional impurities including, but not limited to, aromatic acid impurities, such as benzoic acid and benzoic acid substituted with groups such as methyl, bromine and formyl groups, also as acid 1- and 2-naphthoic and 1- and 2-naphthoic acid substituted with groups such as methyl, bromine and formyl and mixtures thereof. The concentration of monocarboxylic acids in a resuspended NDA is usually about 50 to 5,000 ppm by weight, preferably 100 to 4,000 ppm by weight and more preferably about 150 to 3,500 ppm by weight. As used herein, the term "monofunctional material" means any material related to the process having a single functional group capable of reacting a glycol monomer under typical polymerization conditions. Each of the above materials need not be present in the amounts mentioned above if the desired advantage attributable to that material is not required in the application of the desired monomer. By way of example, the crude NDA can be resuspended to produce an NDA monomer having the appropriate specifications summarized in Table 2 below.

Table 2 Material Trifunctional level 5,500 +/- 1,500 ppm monofunctional 2,000 +/- 1,000 ppm metals (Co + Mn) 1,000 +/- 500 ppm bodies of color 150 +/- 120 ppm Examples 1 and 2 below demonstrate the effect of the cobalt and manganese metal on the polymerization rate of an aromatic polymer. The effect of catalytic metals on the NDA monomer in a purified terephthalic acid (PTA) / naphthalenedicarboxylic acid (NDA) polymer was demonstrated by comparing the polymerization of a mixture of PTA at 92% mol / 8% NDA in catalyzed mol by antimony with ethylene glycol (the polymer is subsequently referred to herein as "PETN-8") with that of a similar mixture that had been "concentrated" with 90 parts per million by weight of cobalt (as cobalt acetate) and ppm by weight of manganese (as manganese acetate). The polymerization times for both mixtures were measured in terms of pressure esterification, atmospheric esterification and polycondensation reactions.

Example 1 In this example, the melt polymerization of PETN-8 without cobalt and manganese concentrations in the range of the invention was demonstrated. The following materials were placed in a 56 liter helical agitator reactor: 12.86 Kg of ethylene glycol, 27.53 Kg of terephthalic acid, 3.12 Kg of 2,6-naphthalene dicarboxylic acid, 1.34 g of tetramethylammonium hydroxide, 8.46 g of antimony trioxide and 3.00 g of cobalt acetate (20 ppm based on polymer yield). The initial temperature of the reactor was 107 ° C and the reactor was pressurized with 0.28 Kg / cm2 (40 psig) of nitrogen pressure. The temperature of the melt was increased to 223-246 ° C and the water was removed while the pressure was maintained at 0.28 Kg / cm2 (40 psig). When the evolution of water stopped, the pressure was reduced to atmospheric pressure and the esterification under pressure was consummated. The pressure esterification time was 218 minutes. Then the temperature of the melt was increased to 263 ° C and the atmospheric esterification was prolonged by 60 minutes. An additional 100 g of ethylene glycol and 3.83 g of phosphoric acid were added. The reactor pressure was decreased from atmospheric pressure to 3 mm of mercury over a period of 65 minutes as the melt temperature was increased to 285 ° C. The polycondensation of the melt was prolonged for an additional 108 minutes for a total of 173 minutes of the polycondensation time to arrive at a torque moment value of the stirrer of 20.74 Kg-m (1800 pounds / inches). The product was formed into strands, turned off and transformed into pellets. The product had an inherent viscosity of 0.58 dl / g measured in phenol / tetrachloroethane 60/40 at 30 ° C and a concentration of 0.4 g / dl.

Example 2 The following example demonstrates the melt polymerization of PETN-8 with cobalt and manganese concentrations present in the range of the invention. Example 1 was repeated with the same materials of raw materials and weights except that 4.42 g (28 ppm based on the weight of the polyester) of manganese acetate were added and the amount of cobalt acetate added was 13.59 g (91 ppm in based on the weight of the polyester). Using identical temperatures and pressures, the pressure esterification time was 220 minutes. The time of esterification at atmospheric pressure was 60 minutes and the polycondensation time at the melt temperature of 285 ° C required to obtain 20.74 Kg-m (1800 pounds / inch) of torque was 117 minutes. The inherent viscosity of the product was 0.59 dl / g. As can be seen by comparing Examples 1 and 2, the pressure and esterification reactions at atmospheric pressure were accomplished in approximately 220 and 60 minutes respectively for both the "concentrated" and control samples of Examples 1 and 2. However, Beneficially, the polycondensation reaction of the "concentrated" sample was accomplished in approximately 117 minutes, compared to approximately 173 minutes for the control sample. It is believed that the substantial reduction in reaction time provides a substantial economic advantage in use. Example 3 below demonstrates that the presence of mono- and tri-carboxylic acid impurities does not adversely affect the melt polymerization of PETN-8.

Example 3 Example 1 was repeated with the same raw material and weights as the control except that 12.57 g of trimellitic acid, 3.80 grams of 2-formyl-6-naphthoic acid, 2.22 grams of 2-naphthoic acid, 0.19 grams of 2-methyl-6-naphthoic acid were added. High purity NDA obtained by the hydrolysis of NDC was used in the control, while the resuspended crude NDA obtained directly from a DMN oxidation was used in the sample according to the invention. The composition and characteristics of the control sample and the sample containing mono- and tri- functional are summarized below. The color bodies were present in the raw sample but were not quantified. Impurity (ppm) Control Invention Tricarboxylic acids None 4,029 Acids Monocarboxylic 109 1,993 Catalyst level (ppm) Cobalt 20 90 Manganese None 30 Antimony 200 200 Processing time (minutes) Esterification 218 215 under pressure Esterification 60 60 Atmospheric Polycondensation 173 118 Properties of Polyester Inherent viscosity, 0.58 0.56 dl / g Color, value * b -0.38 +14.62 It is believed that the reduction in polycondensation time from 173 minutes to 118 minutes according to the present invention is of a major economic significance. With respect to color, it should be noted that the color value * b indicated above is a tristimulus color value on the blue / yellow scale. In this scale, a negative value appears blue and a positive value appears yellow but with values * b greater than approximately +10 the visual appearance is brown. Accordingly, the polyester prepared according to the invention was particularly suitable for beer bottles and other applications of brown containers without the added cost and environmental concern of the addition of an organic dye or pigment. Such polyesters containing color bodies of this invention are also useful as relatively low cost polyesters in applications where white color is not a requirement, such as for industrial fibers and insulating films. Example 4 below illustrates the increased ability of the polymers according to the invention to polymerize in the solid state.

Example 4 3.0 grams of polymer pellets produced from the materials of Examples 1 and 2 were recrystallized in an oven at a temperature of 150 ° C for 2.0 hours. The pellets were placed in test tubes, vacuum was applied and the test tubes were placed in an oil bath at room temperature. The oil was heated for a period of 200 minutes at a temperature of 210 ° C (410 ° F) which was considered as the starting point for solid state polymerization. The samples were periodically removed from the oil bath and the following data were obtained: Time (hours) Inherent viscosity (dl / g) Control Invention Start 0.60 0.58 1.0 0.61 0.62 2.0 0.62 0.64 4.0 0.65 0.68 6.0 0.71 0.73 8.0 0.75 0.77 Speed (dl / g) 0.0188 0.0238 The above data demonstrate an increase in the solid state polymerization rate of about 40% for the invention compared to the control. Examples 5 and 6 below demonstrate that films can be formed and stretched from polymers according to the invention and that the presence of foreign material in the polymer does not adversely affect the film product.

Example 5 Polymerized pellets in solid state according to the invention of example 4 were dried during 16 hours at 150 ° C and extruded in the molten state using a Killion Model KL-125 Single Screw Extruder equipped with a 3.17 cm (1.25 inch) screw with a length to diameter ratio of 24 to 1 (L / D = 24/1). The extruder was equipped with an adjustable 15 cm (6 inch) flange sheet die and 3 cooled temperature rolls for detachment. A heater temperature profile of 268.3 / 273.9 / 276.7 / 276.7 / 276.7 / 260 ° C (515/525/530/530/530 / -500 ° F) (feed throat to the die) was employed and the speed of the screw was 75 rpm A high quality amorphous sheet having a thickness of approximately 0.584 mm (23 mils) was produced.

EXAMPLE 6 Samples of the sheet of Example 6 were biaxially oriented on a T.M extruder. Long. The samples were heated to a temperature of 107.8 ° C -177.8 ° C (226-244 ° F) for a period of 2.0 minutes and stretched at a tension rate of approximately 300% / second to produce 3 x 3 biaxially oriented films . The following film properties were measured: Property Control The invention Crystallinity,% 25. 0 23. 7 Permeation of 34. 2 31. 2 Carbon dioxide (cc-mil inch / 100in2-day-atm @ 35 ° C) As can be seen from the above data, the PETN-8 copolyester sample of the invention containing high levels of monocarboxylic acids and tricarboxylic acids exhibited essentially the same level of crystallinity as the control sample and both films had similar permeation values to carbon dioxide, however, the lower permeation value for the invention results in a longer storage life for packaging applications Both films were very hard and showed no evidence of brittleness Other preferred polyesters that can employ the NDA monomer product according to the present invention include any PTA / NDA polymer having molar proportions of PTA to NDA of 99: 1 to 0: 100. The preferred ranges of NDA to PTA in NDA / PTA polyesters will range from 2 to 15% by mol NDA to 98 to 85% by mol PTA, from 2 to 9% by weight. n mol of NDA at 98 to 91% by mol of PTA is more preferred. The NDAs useful in the invention can be any polymerizable isomer such as 2,6-, 1,5-, 1,4- and 2,7-NDA, also as mixtures thereof. The polyesters may also include up to about 15 mol% of other carboxylic acids such as isophthalic acid and / or adipic acid. The polyester can also incorporate up to about 10 mol% of a glycol such as diethylene glycol, 1,4-butanediol, polybutadieneglycol or 1, -cyclohexanedimethanol or mixtures thereof. With respect to the ranges of materials related to the process summarized in Table 1 above, it should be noted that higher levels of monomer impurities are preferred in the monomeric product designed to be used as small fractions of a copolymer, as long as lower impurities will be preferred where the monomeric product comprises larger fractions of a copolymer or where the final product is a homopolymer. The inherent viscosity of polyesters according to the present invention as measured in a 60/40 solution of phenol / tetrachloroethane at 30 ° C and a concentration of 0.4 grams / dl will normally be between about 0.4 to 1.00 dl / g, of preferably about 0.50-0.90 dl / g and more preferably between about 0.60-0.80 dl / g. The dicarboxylic acid component of the polyesters according to the invention can optionally be modified with up to 15 mol% of one or more different dicarboxylic acids, other than terephthalic acid and 2,6-naphthalene dicarboxylic acid. Such additional dicarboxylic acids include aromatic dicarboxylic acids having preferably 8 to 14 carbon atoms, aliphatic dicarboxylic acids preferably having 4 to 12 carbon atoms or cycloaliphatic dicarboxylic acids preferably having 8 to 12 carbon atoms. Examples of dicarboxylic acids to be included are phthalic acid, isophthalic acid, cyclohexanediacetic acid, 4,4'-biphenyldicarboxylic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, azelaic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, resorcinodiacetic acid, diglycolic acid, 4,4-oxybis (benzoic acid), 1,12-dodecanedicarboxylic acid, 4'-sulphonyldibenzoic acid, 4,4'-methylenedibenzoic acid, trans-4,4'-stilbendicarboxylic acid, 2, 6-dicarboxyltetraine, 2,6-dicarboxydecaline and the like. Other additives and stabilizers known in the art such as glass fibers, mineral reinforcement, oxygen scavengers, diethylene glycol suppressants, optical brightening agents and phosphorus-containing stabilizers can be incorporated into the monomeric product or polymers made therefrom according to the invention. The monomers according to the invention can also be used to produce homopolymers and copolymers from relatively pure acids by adding the materials described above in the amounts summarized herein. For example, metal salts particularly useful for preparing metal-containing monomers include cobalt and manganese alkylates such as acetates, halides, especially bromides and salts of organic acid, particularly aromatic salts. When salts are added to relatively pure aromatic acids, the metal concentrations can range from about 20 to 10,000 ppm by weight, more preferably between about 50 to 2,000 ppm by weight and more preferably between about 100-1,000 ppm by weight. If Co and Mn are added to produce a monomer according to the invention, the molar ratio of Co to Mn can range from 5: 1 to 0.2: 1, the preferred proportions are between 4: 1 to 0.25: 1 and the proportions most preferred are between 3: 1 and 0.5: 1. The polymers according to the invention can be produced in the same way as the polymers are produced from the purest monomers of the same acids. Such polymerization reactions are well known in the art. For example, see "The Encyclopedia of Chemical Technology, Vol. 18, pp. 531-594, John Villey and Sons (1982) the disclosure of which is incorporated herein by reference." Co and homopolymers produced in accordance with the invention. they can be used to manufacture biaxially oriented sheets and films, fibers, stretched blow molded containers and any other application where such polyesters are normally employed, for example, see Plastics Engineering Handbook, 4th Edition, Van Nostrand Reinhold Company (1976), disclosure of which is incorporated herein by reference The presence of metals, color bodies and other impurities in the acidic monomer of the present invention makes these monomers particularly useful in applications of the NDA copolymer wherein the presence of color is desired or non-objectionable, as well as where improved high temperature performance is concerned. Particularly suitable for use in polymers according to the invention are containers for food or beverages that require heating or pasteurization and which must exhibit dimensional stability during and after the heating or pasteurization process. This is especially true where the packaged material contains carbon dioxide or another gas that will generate a substantial internal packing pressure when heated. Specific examples of such applications are pasteurizable bottles for beer bottles for fruit juices, such as plum juice, wherein the packaging heating capacity and color are desired packaging characteristics. The utility of the NDA / PTA copolymers is demonstrated by example 7 below.

EXAMPLE 7 Pasteurizable long-neck, medium-liter beer bottles having a champagne base were manufactured from experimental copolymers containing resuspended acid monomer according to the composition described in Table 2 above. In Example 7A, the PETN-3 copolymer employed had 3 mol% of resuspended NDA and 97 mol% of a purified terephthalic. In this example, an injection molding preform of 35.0 grams was prepared. The preform contained approximately 15 grams of copolymer in the shoulder area, approximately 10 grams of copolymer in the panel area and approximately 10 grams of material in the base area. In Example 7B, the PETN-5 copolymer contained 5 mol% of the resuspended NDA and 95 mol% of the same purified terephthalic acid. In this example, an injection molding preform of 34.1 grams was prepared. The preform contained approximately 14.7 grams of copolymer in the shoulder area, approximately 10 grams in the panel area and approximately 9.4 grams of material in the base area. The preforms of examples 7A and 7B were blown in 0.5 liter bottles using a Sidel SBL2 / 3 stretched blow molding machine. Carbonated water containing approximately 2.9 to 3.1 volumes of carbon dioxide was added to each bottle to a predetermined and capped filling line. The capped bottles were placed in a pasteurization chamber and sprayed with water at 71 ° C until the contents of the bottle reached a temperature of approximately 63 ° C. The temperature of the spray water was then reduced by 64 ° C to maintain the contents of the bottle at a temperature of 63 ° C for an additional 15 minutes. Then the temperature of the spray water was reduced until the contents of the bottle reached 40 ° C, after which time the bottles were cooled to room temperature in a cold water bath. Several physical parameters of the pasteurized bottles were measured to determine the effects on the pasteurization process bottles. The results of those measurements are summarized in Table 3 below.

Table 3 Bottle material PETN-3 PETN-5 IV resin 0.80 0.80 Dimensional changes (% increase) Height 0.43 0.26 Diameter Upper protuberance 1.94 2.15 Medium panel 1.74 0.48 Lower protuberance 1.03 1.04 Neck 1.27 1.36 Line drop of 0.60 0.69 filling ( inches) Perpendicularity 0.119 0.152 (displaced inches bottle center line) Pressure (volumes) 2.71 2.68 In the case of examples 7A and 7B, the dimensional changes of bottle rings were judged acceptable on the basis of pressure retention (at least 75% of the pre-pasteurization pressure was retained when initially charged at a pressure of about 3 volumes) and perpendicularity (vertical deviation smaller than 0.635 cm (0.25 inches) for the vertical radial axis of symmetry of the bottle when the pasteurized bottle is stopped at its base, with the deviation measured at the top of the bottle. Fill line drops of less than 3% are also preferred, and injection molding bottle preforms containing between about 40-46% by weight of their material in the flange region, 26-32, were also found. % by weight of its material in its panel region and 25-31% by weight of its material in the base region were more successful in supporting pasteurization tests. It is believed that these distributions and geomet Approximate preform weight lines are useful for half-liter bottles formed from other polymers and are believed to be scalable to produce pasteurizable bottles of other volumes. While the above examples describe the invention with respect to certain monomeric products of naphthalene acid, those of ordinary skill in the art will recognize that the invention is equally useful in relation to monomers such as terephthalic acid, isophthalic acid and the like, with materials related to the process present in approximately the same ranges when they are corrected for the difference in molecular weight between the naphthalenic monomers and other aromatic monomers. Additionally, when the monomers according to the present invention are used to make copolymers, the process related materials present according to the present invention may be present, for example in any monomer or in more than one monomer. For these reasons, the invention is proposed to be limited only by the scope of the following claims. It is noted that, with regard 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 (21)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A process for producing a product of naphthalene dicarboxylic acid monomer, suitable for the manufacture of polyesters, the process is characterized in that it comprises the steps of : oxidizing a naphthalene feedstock to produce a crude naphthalene dicarboxylic acid; processing the crude naphthalene dicarboxylic acid to produce a naphthalene dicarboxylic acid monomer product comprising at least 90% mol of the acid monomer and one or more process related materials selected from the group consisting of between 50 and 5,000 ppm monofunctional materials, between 50 and 10,000 ppm of trifunctional materials, between 50 and 500 ppm of colored bodies and between 50 and 10,000 ppm of metals.
2. 2. The process in accordance with the claim 1, characterized in that it further comprises the step of polymerizing the naphthalene dicarboxylic acid monomer product of claim 1 in a homopolymer or a copolymer without carrying out an intermediate process step planned to separate the materials related to the process of the monomeric product before of carrying out the polymerization step.
3. 3. The process according to claim 2, characterized in that the processing step includes suspending the crude naphthalene dicarboxylic acid in a solvent selected from the group consisting of water, aliphatic organic acids having between 2 and 4 carbon atoms and mixtures of the same.
4. The process according to claim 3, characterized in that the suspension step is carried out at a temperature of about 75 to 110 ° C, at a pressure of about 1 to 2 atmospheres, wherein the solvent comprises at least 50% mol of acetic acid and a weight ratio of solvent to crude naphthalene acid of about 1: 1 to 10: 1.
5. The process according to claim 1, characterized in that the materials related to the process are selected from the group consisting of between 150 and 3,500 ppm of monofunctional materials, between 150 and 8,500 ppm of trifunctional materials, between 50 and 250 ppm of bodies of color and between 500 and 2,000 ppm of metals and combinations thereof.
6. 6. The process according to claim 1, characterized in that the material related to the process includes between 500 and 2,000 mol% of metals selected from the group consisting of cobalt, manganese and mixtures thereof.
7. The process according to claim 2, characterized in that it further comprises the step of producing a homopolymer or copolymer article from the polymerized naphthalene dicarboxylic acid monomer product, the article is selected from the group consisting of sheets, films, oriented films, fibers, injection molded articles and blow molded articles.
8. The process according to claim 2, characterized in that a copolymer is formed between about 2 and 15% mol of the product of polymerized naphthalene dicarboxylic acid monomer and between about 98 and 85% mol of one or more acids aromatics selected from the group consisting of terephthalic acid, isophthalic acid and adipic acid and mixtures thereof.
9. 9. The process according to claim 2, characterized in that the copolymer is formed from a monomer comprising between about 2 and 9% mol of the product of naphthalene dicarboxylic acid monomer and between about 91 and 98% mol of terephthalic acid.
10. 10. A product of naphthalene dicarboxylic acid monomer suitable for the manufacture of polyesters, the product is characterized in that it comprises at least 90 mol% of the acid monomer and one or more materials selected from the group consisting of between 50 and 5., 000 ppm of monofunctional materials, between 50 and 10,000 ppm of trifunctional materials, between 50 and 500 ppm of colored bodies and between 50 and 10,000 ppm of metals and combinations thereof.
11. The composition according to claim 10, characterized in that one or more of the materials is a material related to the process resulting from the manufacture of the product.
12. The composition according to claim 11, characterized in that the material related to the process is selected from the group consisting of between 150 and 3,500 ppm of monofunctional materials, between 150 and 8,500 ppm of trifunctional materials, between 50 and 250 ppm of colorless bodies and between 500 and 2,000 ppm of metals selected from the group consisting of cobalt and manganese and combinations thereof.
13. A polyester characterized in that it comprises at least 2 mol% of the product of claim 12 and that it has a color and tristimulus value greater than +10 on a yellow / blue scale.
14. 14. A copolymer formed from a monomer, characterized in that it comprises between about 2 and 10 mol% of polymerized naphthalene dicarboxylic acid monomer product of claim 10 and between about 98 and 90 mol% of terephthalic acid.
15. 15. An article formed from the copolymer of claim 14, characterized in that the article is selected from the group consisting of sheets, films, oriented films, injection molded articles and blow molded articles.
16. 16. A process for producing a naphthalene dicarboxylic acid monomer product, the process is characterized in that it comprises the steps of: oxidizing a naphthalene feedstock to produce a crude naphthalene dicarboxylic acid comprising a naphthalene dicarboxylic acid useful as a monomer in a polymerization reaction and process related materials formed during the manufacture of crude naphthalene dicarboxylic acid; suspending the crude naphthalene dicarboxylic acid in a solvent to remove a portion of the materials related to the process of the crude naphthalene dicarboxylic acid; recovering the solid monomer from the suspension to produce a naphthalene dicarboxylic acid monomer product comprising at least 93 mol% of the acid monomer and one or more materials related to the process selected from the group consisting of between 50 and 5,000 ppm of monofunctional materials, between 50 and 10,000 ppm of trifunctional materials, between 50 and 500 ppm of colored bodies and between 50 and 10,000 ppm of metals.
17. The process according to claim 16, characterized in that a recrystallization step between the oxidation step and the recovery step is not carried out.
18. The process according to claim 16, characterized in that it further comprises polymerizing the product of naphthalene dicarboxylic acid monomer in a homopolymer or copolymer without first carrying out an intermediate process step designed to separate the materials related to the process from the product. monomeric before carrying out the polymerization.
19. 19. A pasteurizable blow molded bottle prepared from a polymerized material characterized in that it comprises a copolymer containing between about 2 and 9 mol% of the naphthalene dicarboxylic acid monomer product formed by the process according to claim 16 and between about 98 and 91% mol terephthalic acid, the bottle is able to contain a gas-containing liquid during a pasteurization process in which the temperature of the gas-containing liquid is maintained at a temperature of at least 60 ° C for at least 15 minutes during the process and wherein the bottle is capable of retaining at least 70% of an initial gas pressure when it is charged to an initial gas pressure of approximately 3 volumes of gas per bottle volume.
20. 20. The bottle in accordance with the claim 19, characterized in that, after pasteurization, the bottle has a vertical axis of radial symmetry through the bottle that deviates from the perpendicular of less than 0.635 cm (0.25 inches).
21. 21. The bottle in accordance with the claim 19, characterized in that the bottle is a bottle having a capacity of approximately 500 ml and where the bottle is blown from a preform having a shoulder area, a panel area and a base area, the areas are expanded during the blowing process under exposure to heat and pressure to form a blow molded bottle and in which the shoulder area contains between about 14 to 16 grams of polymer, wherein the panel area contains between about 9 to 11 grams of polymer and wherein the base contains between about 8.5 and 11 grams of polymer.