MXPA00008782A - Polyester resin compositions for calendering - Google Patents

Abstract

A polyester resin composition is calendered to produce a film or a sheet. The polyester resin composition is a polyester having a crystallization half time from a molten state of at least 5 minutes combined with an additive for preventing sticking of the polyester to calendering rolls.

Description

H.

RESSNA POLSESTER COMPOSSCONS FOR CALENDERING TECHNICAL FIELD OF THE SNVENCSON This invention is concerned with the manufacture of a film and sheet using calendering processes and more particularly with the use of polyesters in such calendering processes.

BACKGROUND OF THE SNVENCSON Calendering is an economical and highly efficient means of producing film and sheet from plastics such as plasticized and rigid polyvinyl chloride (PVC) compositions. Films and sheets usually have a thickness in the range of about 0.05 mm (2 mils) to about 1.14 mm (45 mils). They are easily thermoformed in various forms and are used for a wide variety of packaging applications. The calendered PVC film or sheet can be used in a wide range of applications including swimming pool liner, graphic arts, transaction cards, security cards, plywood, wall coverings, book binding, folders, mosaics floor and products that are printed or decorated or laminated in a secondary operation. Japanese application No. Heisei 7-197213 (1995) issued to E. Nishimura et al. and European patent application 0 744 439 A1 (1996) issued to Y. Azuma _ et al. describe the state of the art with respect to the polypropylene resin compositions used in the calendering processes. In a typical calendering process line, the plastic resin is mixed with specific ingredients such as stabilizers to prevent thermal degradation, modifiers for clarity, characteristics of thermal stability or opacity, pigments, lubricants and processing aids; static, UV inhibitors, and flame retardants.The mixed ingredients are plasticized in a kneader or extruder.With heat, cut and pressure, the dry powders are melted to form a homogeneous molten material.The extruder feeds the molten material in a process continuous to the upper end of the calendering section of the calendering line between the first and second heated calendering rollers Normally, four rollers are used to form three separations or spaces between rollers.The rollers are configured in an "L" shape or from X? L "inverted. The rollers vary in size to accommodate different film widths. The rollers have separate temperature and speed controls. The material advances through the space between rollers between the first two rollers, which is called the space between feed rollers. The rollers rotate in opposite directions to help distribute the material across the width of the rollers. The material is wound between the first and second, second and third, third and fourth rollers, etc. The separation between the rollers decreases in thickness between each of the rollers, in such a way that the material is thinned between the set of rollers as it advances. After passing through the calendering section, the material moves through another series of rollers where it is stretched and gradually cooled to form a film or sheet. Then, the cooled material is rolled into master rollers or master rollers. General descriptions of calendering processes are described in Jim Butschli, Packaging World, p. 26-28, June 1997 and W.W. Titow, PVC Technology, 4th edition, p.p. 803-848 (1984), Elsevier Publishing Co., both incorporated herein by reference. Although PVC compositions have so far consisted of the largest segment of the calendered films and sheets trade, small quantities of other thermoplastic polymers such as thermoplastic rubbers, certain polyurethanes, talcum-filled polypropylene, acrylonitrile / butadiene / styrene terpolymers (ABS resins) and chlorinated polyethylene are sometimes processed by calendering methods. Attempts to calender polyester polymers such as poly (ethylene terephthalate). ~ { EE-T) "or poly (1-terephthalate), 4-butylene) (PBT) have not been successful. For example, PET polymers with inherent viscosity values of about 0.6 dl / g have insufficient melting strength to develop properly on the calendering rolls. Also when the polyester is fed to the rolls at typical processing temperatures of 160 ° C to 180 ° C, the PET polymer crystallizes causing an inhomogeneous mass which is unsuitable for further processing. The inhomogeneous mass causes large unwanted forces on the calendering bearings. The tendency of polyester polymers to hydrolyze during processing in the molten or semi-molten state on rollers open to ambient conditions is also a concern. Typical PET polymers without the inclusion of process lubricants or internal release additives also have a tendency to adhere to the calendering rolls at typical processing temperatures. Conventional processing of polyesters to a film or sheet involves extruding a molten polyester through a multiple tube of a flat mold. The manual or automatic adjustment of the flange of the mold is used to control the thickness through the network of material. Water-cooled protection rollers are used to cool the cloth or cast tape and impart a smooth surface finish. A typical mold extrusion process is "" "" shown in Figures 2A and 2B. Extrusion processes, while producing excellent film and sheet quality do not have the performance and economic advantages that are provided by the calendering process. Thus, there is a need in the art for an efficient and economical process for making films and sheets of polyester as an alternative to extrusion processes. Thus, it is the provision of such a solution with which the present invention is concerned.

BRIEF DESCRIPTION OF THE SNVENCSON A polyester resin composition for calendering is disclosed as comprising a polyester having a half-life of crystallization from a molten state of at least 5 minutes and an additive to prevent adhesion of the polyester to the calendering rolls. In another embodiment of the invention a process for preparing a film or a sheet comprising the step of calendering such a polyester resin composition is described.

BRIEF DESCRIPTION OF THE DIVESCRIPTION Figure 1 is a diagram of the calendering process of the polyester of the present invention; Figure 2A is a schematic of the polymer flow in a flat mold manifold tube used in eP "extrusion process of the prior art for the polyester film Figure 2B is a schematic of a portion of the extrusion process of the art preamp for polyester film. "-" Figure 3 is a graph showing the rolling bearing force with respect to time for examples 2 and 3. Figure 4 is a graph showing the separation of rollers with respect to time for examples 2 and 3. Figure 5 is a graph showing the torque of the roller with respect to time for examples 2 and 3.

DETAILED DECLINE OF THE SNVENCSON Certain amorphous or semi-crystalline polyester resin compositions are unexpectedly calendared using conventional calendering processes to produce uniform films and sheets. The polyester resin compositions comprise a polyester having an average crystallization time from a molten state of about 5 minutes and an additive to prevent adhesion to the calendering rolls. The films and sheets typically have a thickness in the range of about 0.05 mm (2 mils) to about -2 mm (80 mils). Polyesters useful in the practice of this invention include polyesters that have an average crystallization time from a molten state of at least 5 minutes, preferably about 12 minutes. The term "polyesters" as used herein is intended to include copolyesters. Amorphous polyesters are preferred because they have an average time of infinity crystallization. The desired crystallization kinetics of the melt can also be obtained by adding polymer additives or altering the molecular weight characteristics of the polymer. A particularly useful technique is to mix amorphous polyester or very slow crystallization polyester with the polyester base. The mean crystallization times as defined in the present invention are measured using a differential scanning calorimeter Perkin-Elmer Model DSC-2. Each 15.0 mg sample is sealed in an aluminum container and heated to 290 ° C at a rate of approximately 320 ° C / min. for 2 minutes. The sample is then immediately cooled to the predetermined isothermal crystallization temperature at a rate of about 320 ° C / minute in the presence of helium. The mean time of crystallization is determined as the time of arrival of the isothermal crystallization temperature to the point of a peak of crystallization in the DSC curve. Preferred polyesters comprise (i) at least 80 mol% of a diacid residue component selected from terephthalic acid, naphthalene dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid or mixtures thereof and (ii) by at least 80% by mol of a diol residue component of the diols containing from 2 to about 10 carbon atoms and mixtures thereof. The diacid residue component is based on 100 mol% and the diol waste component is based on 100 mol%. For the diacid residue component, any of several isomers of naphthalenedicarboxylic acid or mixtures of isomers may be used, but the isomers 1,4, 1, 5-, 2,6- and 2,7- are preferred. Also mixtures of cis, trans ~ or mixtures of cis / trans isomer of 1,4-cyclohexanedicarboxylic acid can be used. Sulfoisophthalic acid can also be used. The diacid residue component can be modified with minor amounts of up to about 20 mol% of other diacids containing about 4 to about 40 carbon atoms and includes succinic acid, glutaric acid, azelaic acid, adipic acid, suberic acid, sebacic acid , dimeric acid and the like.; ~~~ - For the diol residue component, the preferred diols include ethylene glycol, diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol and mixtures thereof. More preferably, the diol residue component is from about 10 to 100% mol 1, 4-cyclohexanedimethanol and from about 90 to 0% mol ethylene glycol. The diol residue component can also be modified with up to about 20 mol% of other diols. Suitable modified diols include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, propylene glycol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol and the like. - The inherent viscosity (I.V.) of the useful polyesters is generally in the range from about 0.4 to about 1.5 dl / g, preferably from about 0.6 to about 1.2 dl / g. I.V. as used herein refers to the determination of the inherent viscosity at 25 ° C using 0.25 grams of polymer per 100 ml of a solvent composed of 60% by weight of phenol and 40% by weight of tetrachloroethane. Amorphous polyesters are manufactured by melt phase techniques well known in the art. The semicrystalline polyesters can be manufactured by a combination of molten phase and solid-phase co-depletion procedures well known in the art. In addition to polyester, the polyester resin composition for calendering also includes an additive which prevents the polyester from sticking to the calendering rolls. The amount of additive used in the polyester resin composition is usually about 0.01 to 10% by weight based on the total weight percent of the polyester resin composition.The optimum amount of additive used is determined by factors well known in the art and variations in the equipment, material, process conditions and thickness of the film material are considered.Additives suitable for use in the present invention are well known in the calendering art and include internal lubricants, agents for slip or slurry or mixtures thereof Examples of such additives include fatty acid amides such as erucilamide and stearamide, metal salts or organic acids such as calcium stearate and zinc stearate, fatty acids and esters such as stearic acid, oleic acid and palmitic acid; hydrocarbon waxes such as paraffin wax, polyethylene waxes, ester waxes such such as carnauba, mono- and di-glycerol stearates, talc; and acrylic copolymers (e.g., PARALOID K175 available from Rohm &Haas). Antiblock and disintegrating auxiliaries such as microcrystalline silica and erucilamide are also frequently used Conventional oxygen stabilizing agents can also be used with the polyesters of the present invention to prevent oxygen degradation during the processing of the molten material. semi-cast on the rollers. Suitable stabilizers include esters such as distearyl thiodipropionate or dilauryl thiodipropionate; phenolic stabilizers such as IRGANOX 1010 available from Ciba-Geigy AG, ETHANOX 330 r available from Ethyl Corporation and butylated hydroxytoluene and phosphorus-containing stabilizers such as IRGAFOS available from Ciba-Geigy AG and WESTON stabilizers available from GE Specialty Chemicals. These stabilizers can be used alone or in combinations. Sometimes the melt viscosity and the melting strength of the polyester are insufficient for proper processing in the calendering equipment. In these cases, the use of an agent that improves the strength of the melt is desirable, such as by the addition of small amounts (from about 0.1 to about 2.0 mol%) of a branching agent to the polyesters either during their preparation Initial or during its subsequent mixing or feeding procedures before it reaches the calendering equipment. Agents ofSuitable branching includes multifunctional or glycol acids such as trimellitic acid, trimellitic anhydride, pyromelitic dianhydride, trimethylolpropane, glycerol, pentaerythritol, citric acid, tartaric acid, 3-hydroxyglutaric acid and the like. These branching agents can be added directly to the polyester or mixed with the polyester in the form of a concentrate as described in U.S. Patent Nos. 5,654,347 and 5,696,176. It is also possible to use agents such as sulfoisophthalic acid to increase the melt strength of the polyester to a desired level. In addition to the additives described above, other typical additives used with polymers can be used as desired. These include plasticizers, dyes, colorants, pigments, fillers, fabric agents, antiblocking agents, antistatic agents, staple fibers, glass, impact modifiers, flame retardants, carbon black, talc, Ti02 and the like. In another embodiment of the present invention, a process for the preparation of a film or sheet comprising the step of calendering the polyester resin composition described above is described. Conventional calendering processes and equipment are used to calender the polyester resin composition. Calenders having at least two adjacent heated rollers are suitable for processing the polyester resin composition, which is introduced between the two rollers in the form of pellets, powder or melt. The rollers may be in series or have a configuration of "L", "L" inverted or, Z ". Typical processing temperatures for the rollers will generally be in the range of 130 ° C to about 250 ° C, preferably approximately 140 ° C to approximately 190 ° C. " The pre-drying of the polyester resin composition or the ventilation of excess moisture during processing is preferred to prevent degradation of the polymer by hydrolysis. With reference to Figure 1, an inverted "L" configuration is used for the four heated rollers 10, 12, 14 and 16. The four rollers form three separations or spaces between rollers. A space between feed rolls 18 is formed between the first roll 10 and the second roll 12. A measured roll gap 20 is formed between the second roll 12 and the third roll 14. A space between finishing rolls 22 is formed between third roller 14 and fourth roller 16. A hot strip or rod 24 of the molten polyester resin composition is uniformly fed by a feed device 26 pivotally mounted in the space between feed rollers 18. The molten composition is preferably a homogeneous measured material that leaves the composition or extrusion operation (not shown). The molten composition can be further mixed and heated by the circulating melt bank formed in the space between feed rollers 18. The molten composition is optionally forced between the first roller 10 and the second roller 12 by the rotating action of the rollers, then forced through the space between measuring rollers 22 for reduction to their final desired thickness and finally forced through the space between finishing rollers 22 to form a film or sheet 28 of a particular caliber The resulting film or sheet 28 made from the polyester resin composition of the present invention has a uniform thickness that is produced by passing the resin composition The polyester resin composition is compressed in the spaces between the rollers separating the rollers, and each successive space between rollers between the calendering rollers is reduced. in size of the opening to obtain the final film or sheet gauge. Figures 2Á and 2B, the prior art extrusion technique for producing polyester film or sheet uses a heated flat mold 30. A molten polyester supplied with a screw extruder "(not shown) enters the mold 30 at the entrance 32 of the" - "cast The melt is forced to flow uniformly across the width of the mold 30 by an internal distribution manifold 34. This uniform flow must continue through the flat part of the mold 36 and the outlet plane 38. The extruded strip 40 of hot polymer is cooled on water cooled rolls 42. Final gauge control can be done by adjusting a mold flange The present invention of calendering a polyester resin composition has some significant advantages over the extrusion of polyesters as A method of producing film or foil A significant advantage is the retention of inherent viscosity after calendering compared to before calendering As is evident from the data in Table 2, the inherent viscosity of the polyester resin composition is retained at most 90%, more preferably 95%. Other advantages include high production speeds, good thickness control and convenience for long, continuous production runs. For example, modern PVC calendering processes, which would be analogous to the polyester calendering processes of the present invention, produce yields of more than 3000 Kg / h and sheets having a thickness tolerance of +/- 2% on sheets of 0.25 mm thick. The sheets can have widths greater than 2500 mm, which compares quite favorably with respect to a typical sheet extruder for the production of film or polyester sheet. The typical extrusion process has yields of 500 to 750 Kg / h, has a thickness tolerance of +/- 5% for a 0.25 mm thick sheet and provides a sheet width of 1000 mm. The improved consistency of films or sheets manufactured using the calendering process allows for less training time and less heating and adjustments of the cycle process during secondary training operations. The economic advantages are also evident in terms of the cost of conversion per Kg of sheet obtained through the calendering processes of high production with respect to the extrusion processes. Thus, the present invention provides films and sheets made by calendering the polyester resin composition which have an excellent appearance and can be used in a wide range of decorative and packaging applications. Films and sheets are easily thermoformed in various forms for specific packaging applications for food and non-food products. They can be printed with a wide variety of inks and can be laminated either online or offline with fabrics or other plastic films or sheets. Some specific end users could include, graphic arts, transaction cards, security cards, wall coverings, book bindings, folders and the like. This invention may be further illustrated by the following examples of the preferred embodiments thereof, although it will be understood that these examples are included simply for purposes of illustration and are not intended to limit the scope of the invention unless specifically indicated otherwise. way.

Examples 1 to 7 Polyester compositions A and B are pre-dried at 65 ° C for 12 hours in a dehumidified dryer and compounded with various additives as listed in Table 1, using a 30 mm co-rotating twin screw combiner extruder. Werner Pfleiderer 40: 1 L / D. 1) Polyester A: Polyester containing an acid component of 100 mol% terephthalic acid and a glycol component of 31% mol. 1,4-cyclohexanedimethanol and 69%. "-in -mol ethylene glycol 2) Polyester B: Polyester containing an acid component of 100 mol% terephthalic acid and a glycol component of 3. 5% mol 1, 4-cyclohexanedimethanol and 96.5% ethylene glycol 3) PARALOID K175 is an acrylic processing additive available from Rohm & Haas. 4) This is a mixture of IRGANOX 1010, which is a phenolic stabilizer available from Ciba-Geigy AG, and DSTDP, which is a distearyl thiodipropionate commonly available in the industry. The mixture consists of 0.3% of the first and 0.2% of the last. 5) MYVEROL 1806 is a glycerol monostearate available from Eastman Chemical Company of Kingsport, TN, which is used as an internal lubricant. 6) Zn stearate is used as a slip additive. 7) KENAMIDA S is a fatty acid amide available from Witco Corporation, which is used as a slip additive. The extruded compositions are then re-dried to 65 ° C for 8 hours and sealed in metal lining bags to prevent moisture absorption. The compositions are then calendered to films having a thickness of 0.2 mm using an automated measuring roller mill available from Dr. Collin Gmbh d & "Ebersberg, Germany at a set roller temperature of 165 ° C. The rolling force exerted on the rollers, the roll torque, calendering capacity, weight average molecular weight and polymer crystallinity are measured and summarized in Table 2 and Figures 3 to 5. Table 2 * Excessive adhesion to the calendering rollers - it is not possible to detach the film ** The crystallization in the calendering rollers prevents the formation of a molten film. Figure 3 shows the rolling force of the roller with respect to time for examples 2 and 3. The composition of example 2 exhibits good calendering ability which is evident by the rolling force of the stable roller with respect to time . Example 2 has "an average infinity crystallization time." The composition of Example 3 crystallizes easily between the heated rolls, resulting in a high force being exerted on the roller bearings, thus being unsuitable for calendering. Figure 4 shows the space between rollers with respect to time for examples 2 and 3. Example 2 is calendered to a set of spaces between rolls, however, example 3 it has morphological changes associated with crystallization, which create forces that cause the rollers to separate, Figure 5 shows the torsional force of the roller with respect to time for examples 2 and 3. Example 2 has a torque of consistent roller and uniform calendering behavior Example 3 has an inconsistent torque before the rollers are unloaded - Examples 1-7 demo They analyzed the feasibility of calendering polyesters. Polyester A was an amorphous ppliester that has an average time of infinity crystallization. Polyester B has an average crystallization time of less than 5 minutes and one was easily calendered.

Example 8 Using the procedure of the compound of example 1, a polyester containing an acid component of 100 mol% terephthalic acid and a glycol component of 12 mol% 1-cyclohexanedimethanol and 88 mol% ethylene glycol (IV of 0.74 ) was combined with 1.0 wt% zinc stearate and 1.0 wt% MYVEROL 1806. The material was heated to its 260 ° C molten state and then transferred to a hot roll mill calender. The copolymer was calendered through the spaces between the compression rollers on the rollers of the calender to a final sheet thickness of 0.65 mm. This example demonstrated the feasibility of calendering a polyester having an average crystallization time of 12 minutes.

Claims (32)

1. RESVSNDSCACSONES -. A polyester resin composition for calendering, characterized in that it comprises (a) a polyester having an average crystallization time from a molten state of at least 5 minutes and (b) a sufficient amount of an additive, in wherein said additive prevents adhesion of the polyester to the calendering rolls.
2. 2. The polyester resin composition according to claim 1, characterized in that the average crystallization time of the polyester is at least 12 minutes.
3. 3. The polyester resin composition according to claim 1, characterized in that the polyester is amorphous and has an average crystallization time of infinity.
4. 4. The polyester resin composition according to claim 1, characterized in that the polyester comprises (i) at least 80 mol% of a diacid residue component selected from terephthalic acid, naphthalenedicarboxylic acid, 1,4- cyclohexanedicarboxylic acid, isophthalic acid and mixtures thereof and (ii) at least 80% by mol of diol residue components selected from diols containing 2 to about 10 carbon atoms and mixtures thereof, wherein the waste component of diacid is based on 100 mol% of the diol waste component and the residue component is based on 100 mol%.
5. The composition of polyester resin according to claim 4, characterized in that the diol residue component is selected from ethylene glycol, neopentyl glycol, diethylene glycol, 1,4-cyclohexanedimethanol and mixtures thereof.
6. The polyester resin composition according to claim 4, characterized in that the diol waste component comprises from about 10 to about 100% mol of 1,4-cyclohexanedimethanol and from 90 to about 0% mol of ethylene glycol.
7. The polyester resin composition according to claim 1, characterized in that the additive is an internal lubricant, a slip agent or a mixture thereof
8. 8. The polyester resin composition according to claim 1, characterized in that it further comprises (c) an oxygen stabilizing agent
9. 9. The polyester resin composition according to claim 1, characterized in hoisted because it also comprises (d) an agent that increases the strength of the melt.
10. 10. A process for the preparation of a film of a sheet, characterized in that it comprises the step of calendering a polyester resin composition "comprising (a) a polyester having an average crystallization time of a molten state of at least 5 minutes and (b) an additive which prevents the adhesion of the polyester to the calendering rollers
11. 11. The process according to claim 10, characterized in that in the calendering step, the composition of the polyester resin is It passes through a space between compression rollers between at least two rollers at temperatures of about 130 ° C to about 250 ° C.
12. 12. The process according to claim 10, characterized in that in the calendering step, the The polyester resin composition is passed through a compressive roll space of at least two calendering rolls at temperatures from about 140 ° C to about 190 ° C.
13. 13. The process according to claim 10, characterized in that before the calendering step, the polyester resin composition is in molten form, agglomerate or powder.
14. 14. The process according to claim 10, characterized in that the mean crystallization time of the polyester is at least 12 minutes.
15. 15. The process according to claim 10, characterized in that the polyester is amorphous having an average crystallization time of infinity.
16. 16. The process according to claim 10, characterized in that the polyester comprises (i) at least 80 mol% of a diacid residue component selected from terephthalic acid, naphthalene dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid and mixtures thereof and (ii) ) at least 80 mol% of a diol residue component selected from diols containing 2 to about 10 carbon atoms and mixtures thereof, wherein the diacid residue component is based on 100 mol% of a waste component of diol and the diol waste component is based on 100% mol.
17. 17. The process in accordance with the claim 16, characterized in that the diol waste component is selected from ethylene glycol, neopentyl glycol, diethylene glycol, 1,4-cyclohexanedimethanol and mixtures thereof.
18. 18. The process in accordance with the claim 16, characterized in that the diol waste component comprises from about 10 to about 100% mol 1, 4-cyclohexanedimethanol and from 90 to about 0% mol ethylene glycol.
19. The process according to claim 10, characterized in that the additive is an internal lubricant, a slip agent or a mixture thereof.
20. 20. The process according to claim 10, characterized in that before the calendering step, an oxygen stabilizing agent is added.
21. 21. The process according to claim 10, characterized in that before the calendering step, an agent is added that increases the strength of the melt.
22. 22. The process according to claim 10, characterized in that the polyester resin composition has an inherent viscosity retention of more than 90% after calendering as compared to before calendering.
23. 23. The process according to claim 22, characterized in that the viscosity retention is greater than 95%.
24. 24. A film or sheet manufactured by a process characterized in that it comprises the step of calendering a polyester resin composition comprising (a) a polyester having an average crystallization time of a molten state of at least 5 minutes and (b) ) an additive to prevent adhesion of the polyester to the calendering rollers.
25. 25. The film or sheet according to claim 24, characterized in that in the calendering step, the composition is passed through, from "a compressive space of at least two." Calendering rolls at temperatures of about 130 ° C to approximately 250 ° C.
26. 26. The film or sheet according to claim 24, characterized in that the average crystallization time of the polyester is at least 12 minutes.
27. 27. The film or sheet according to claim 24, characterized in that the polyester is amorphous and that it has an average crystallization time of infinity.
28. 28. The film or sheet according to claim 24, characterized in that the polyester comprises (i) at least 80 mol% of a diacid residue component selected from terephthalic acid, naphthalene dicarboxylic acid, 1,4-cyclohexane acid -dicarboxylic acid, isophthalic acid and mixtures thereof and (ii) at least 80% by mol of a diol residue component of the diols containing 2 to about 10 carbon atoms and mixtures thereof, wherein the component The diacid residue is based on 100% mol and the diol residue component is based on 100 mol%.
29. 29. The film and sheet according to claim 28, characterized in that the diol residue compound is selected from ethylene glycol, neopentyl glycol, diethylene glycol, 1,4-cyclohakanedimethanol, and the like.
30. The film or sheet according to claim 28, characterized in that the diol residue compound comprises from about 10 to about 100% mol, 1,4-cyclohexanedimethanol and from 90 to about 0% in ethylene glycol mole
31. 31. The film or sheet according to claim 28, characterized in that the polyester resin composition has an inherent viscosity retention of more than 90% after calendering as compared to before calendering. film or sheet of claim 31, characterized in that the viscosity retention is greater than 95%.