CA2264857A1 - Polyester resin composition and bottle produced from the resin composition - Google Patents

Abstract

A resin composition comprising polyethylene terephthalate and polyethylene naphthalate, a process for producing the composition, a bottle produced from the composition, and a process for producing the bottle. The resin composition is prepared by melt-mixing (A) polyethylene terephthalate with (B) polyethylene naphthalate in such a ratio that the proportion of ethylene naphthalate units is 5 to 15 mol % based on the sum of (A) and (B) with an extrusion kneader while regulating the ratio of the extruder output to the rotational speed of the screw to 0.1 to 1.4 kg/hr.rpm. The composition has a degree of transesterification of 20 % or lower and, despite this, can give bottles with high transparency and high resistance to hot pressing in high-speed production facilities.

Description

CA 02264857 1999-03-03MCCARTHY TETRAULT FILE: 057377—24944OAPPLICANT: MITSUBISHI PLASTICS, INC.INVENTORS: SHUN-ICHI NISHIHARATATEO KANESAKIMASATOSHI OGISHITAMASANOR HATATITLE: POLYESTER RESIN COMPOSITION ANDBOTTLE PRODUCED FROM THE RESINCOMPOSITION510152025CA 02264857 1999-03-03E. H I I | I.The present invention relates to a resin composition comprising polyethyleneterephthalate and polyethylene naphthalate and a process for preparing thecomposition. The present invention relates also to a bottle produced from thecomposition and a process for the preparation of the bottle.E..HE.,Plastic hollow containers are light and have good impact resistance and henceare widely used as containers for various kinds of liquids. Among them, hollowcontainers such as a bottle produced by stretch blow molding polyethyleneterephthalate, i.e. bottles, are widely used as containers for beverages such asjuice, soft drinks, and carbonated drinks, because they are easily produced andexcellent in clarity and mechanical properties.Recently, improved qualities such as heat resistance and gas barrier propertyover those of current containers are desired to allow bottle—filling under sterilizationat an elevated temperature and an extended storage period of bottle contents.For example, containers are filled with carbonated beverages at a low temperature.The containers are capped and placed in a warm water bath to be subjected tosterilization or disinfection at an elevated temperature. During the sterilization, amouth and neck part and a bottom part of the bottle are exposed to heat andpressure, which causes the container to swell or cause the bottom part to protrudedue to the heat creep phenomenon. One way to solve this problem currentlyemployed is to attach a polyethylene base cup to a round bottom part of a bottle to 10152025CA 02264857 1999-03-03produce a container with a base cup. However, such a container with a base cuphas a drawback of an increased production cost caused by an additional processfor attaching a base cup. Also in the reclamation of such a container, separationof the base cup from the container body is required, because they are made ofdifferent materials. This makes the reclamation difficult. Another drawback is thatit is difficult to secure a flow route for hot water during the sterilization of thecontents.Meanwhile, self-standing containers(bott|es) having a plurality of legs at a bottomin stead of a base cup, which are capable of standing by themselves, are employed.However, the self~standing bottles are limited in use. For example, conditions ofthe sterilization of bottle contents should be mild. To improve heat and pressureresistance of the self-standing containers, a step of clouding-crystallizing a mouthand neck part of the bottle which part tends to change the shape in the heatingsterilization is practiced, so as to make the crystallinity of the part within apredetermined range. Alternatively, heat setting of a barrel part and a bottom partis practiced. However, these treatments make the process complicated todecrease production throughput, and also are difficult to control due to their narrowcontrol ranges. For example, although an increase in the crystallinity raiseshardness of a container and thus restrains the deformation caused in the heatingsterilization, too much increase makes the hardened part of the container brittle tobe easily broken when a mechanical impact is applied to the container.Thus, a container which has a property that it does not change the shape in theheating sterilization and maintains its self-standing capability is desiredHereinafter, the property is referred to as " resistance to heat and pressure".Polyethylene naphthalate that is known to be superior to polyethyleneterephthalate in heat resistance and in gas barrier property has been examined to10152025CA 02264857 1999-03-03be used for a bottle and a film to improve resistance to heat and pressure. Forexample, in JP Laid Open 52-45466, a bottle consisting of a polyethylenenaphthalate homopolymer and having an excellent heat resistance and gas barrierproperty is described. However, polyethylene naphthalate is expensive,compared to polyethylene terephthalate that is mass-produced for fibers, films andmolding applications, so that the polyethylene naphthalate homopolymer is notcommercially used.To take advantage of the superior heat resistance and the gas barrier property ofpolyethylene naphthalate, blends of polyethylene terephthalate with polyethylenenaphthalate or polyethylene terephthalate naphthalate copolymers are proposedand described in, for example, JP Laid Open 50-122549, JP Laid Open 2-276877,JP Laid Open 2-274757, JP Laid Open 3—43425, RESEARCH DISCLOSURE,29410, pp. 714-719(1988), and RESEARCH DISCLOSURE, 29484, pp.807-814(1988).However, since compatibility between polyethylene terephthalate andpolyethylene naphthalate is bad, their mixtures usually have milky white color andshow bad clarity. Therefore, to obtain a transparent blend of polyethyleneterephthalate and polyethylene naphthalate, it is necessary to causetransesterification reaction by melt-mixing thereby to make the molecular structurecloser to that of a random copolymer. To attain sufficient clarity, a long reaction timeabove the melting points of the resins is required. Especially when a proportion ofthe ethylene naphthalate unit to the total of polyethylene terephthalate andpolyethylene naphthalate is about 10 mole%, it is believed that thetransesterification reaction should proceed to a considerable extent, as describedin, for example, JP Laid-Open 9-52277.The present inventors tried to find molding conditions to obtain a transparent10152025. because of the limited reaction time.CA 02264857 1999-03-03blend by directly melt-mixing and molding polyethylene terephthalate andpolyethylene naphthalate with an injection molding machine, and concluded that, ina small scale production machine, a production speed could be slower to prolong aresin residence time, and therefore a transparent blend could be obtained; andhowever, in a recently developed high-speed bottle production unit with an outputrate exceeding 300kg per hour, a transparent molded article could not be obtainedAlso, in a conventional process of melt-mixing polyethylene terephthalate with polyethylene naphthalate with a kneadingextruder, a transparent molded article was difficult to obtain in a high-speedproduction unit due to the limited reaction time. Prolonging a reaction time orraising a molding temperature to enhance the reaction causes degradation of theresin or formation of thermal decomposition products such as acetaldehyde, whichis not desirable especially in the beverage bottle application where preservation oftastes and aroma is important.Thus the first object of the present invention is to provide a resin compositionwhich makes it possible to produce a transparent bottle made from a blend ofpolyethylene terephthalate with polyethylene naphthalate even in high-speedbottle production facility, and a process of the resin composition, by solving theabove-mentioned problems.The second object of the present invention is to provide the resin compositiondescribed in the above paragraph, wherein a heat resistance is improved.The third object of the present invention is to provide a bottle preform to be usedto produce a polyester bottle having a high resistance to heat and pressure, and aprocess for preparing the preform.The fourth object of the present invention is to provide a blended polyesterbottle having a low content of acetaldehyde, one of thermal decomposition10152025CA 02264857 1999-03-03products.The fifth object of the present invention is to provide a self-standing bottle whichshows a high resistance to heat and pressure and allows easy reclamation withoutbeing provided with a base cup or being subjected to crystallization treatment.Further, the sixth object of the present invention is to provide a process forpreparing the above-mentioned self-standing bottle.The seventh object of the present invention is to provide a process for preparinga self-standing bottle superior in moldability and a resistance at dropping.E. l E H I I.The present invention relates to a process for preparing a polyester resincomposition, characterized by melt-kneading (A) polyethylene terephthalate with(B) polyethylene naphthalate in a proportion of the ethylene naphthalate unit to atotal of (A) and (B) of from 5 to 15 mole% with a kneading extruder in a ratio of anextruder output rate to a screw rotation speed of 0.1 to 1.4kg/hr- rpm.The present invention also relates to a polyester resin composition comprising(A) polyethylene terephthalate and (B) polyethylene naphthalate, characterized inthat a proportion of the ethylene naphthalate unit to a total of (A) and (B) is from 5to 15 mole%, and that a transesterification ratio is 20% or less, or a coldcrystallizing temperature, determined by differential scanning calorimetry, is 140°Cor higher, and also relates to resin pellets comprising the composition and a bottlepreform made from the composition.Further, the present invention relates to a polyester resin composition preparedby melt-kneading (A) polyethylene terephthalate and (B) polyethylene naphthalate,characterized in thata. a proportion of the ethylene naphthalate unit to a total of (A) and (B) is from10152025CA 02264857 1999-03-055 to 15 mole%,b. a transesterification ratio is 20% or less, andc. a content of the diethylene glycol ester unit in (A) polyethylene terephthalateis 1.5 mole% or less based on (A).As one embodiment of the present bottles, a polyester resin bottle is providedwhich is characterized in that the bottle comprises (A) polyethylene terephthalateand (B) polyethylene naphthalate in a proportion of the ethylene naphthalate unit toa total of (A) and (B) of from 5 to 15 mole°/o, that a haze at a barrel part of saidbottle is 3% or less, and that a content of acetaldehyde is 20ppm or less.Another embodiment of the present bottle is a polyester self-standing bottle,characterized in that the bottom part of said bottle has a plurality of leg partsextending below from a hemispherically curved bottom face with said leg partsbeing disposed at an approximately regular interval along the circumference of thebottom face, and that said polyester resin bottle comprises a polyester resincomposition comprising (A) polyethylene terephthalate and (B) polyethylenenaphthalate in the proportion of the ethylene naphthalate unit to a total of (A) and(B) of from 5 to 15 mole%, and having a transesterification ratio of 5 to 30 % and anintrinsic viscosity of 0.70 dl/g or larger.Preferably, the afore-mentioned polyethylene naphthalate (B) comprises anester component or components other than the ethylene naphthalate component ina proportion of 15mole°/o or less, more preferably 10% or less, and most preferably8 mole% or less.Also, (B) polyethylene naphthalate is preferably polyethylene 2,6-naphthalenedicarboxylate. It is especially preferred that (B) polyethylene naphthalate is apolyethylene terephthalate naphthalate copolymer comprising 8 mo|e°/o of anethylene terephthalate component.10152025CA 02264857 1999-03-03The present invention relates to a process for preparing a self—standing bottle,comprising a step of biaxial-stretch blow molding a preform in a circumferentialstretch ratio of 3.7 to 4.3 and a longitudinal stretch ratio of 2.7 to 3.3, wherein saidpreform comprises a polyester resin composition comprising (A) polyethyleneterephthalate and (B) polyethylene naphthalate in a proportion of the ethylenenaphthalate unit to a total of (A) and (B) of from 5 to 15 mo|e°/o, and having anintrinsic viscosity of 0.70 dl/g or larger.Further, the present invention provides a process for preparing a bottle superiorin moldability and in resistance at dropping, characterized in that use is made of aresin composition prepared by steps of(1) melt-mixing polyethylene terephthalate and polyethylene naphthalate in aproportion of the ethylene naphthalate component to a total of the polyethyleneterephthalate and the polyethylene naphthalate of 20 to 50 mole°/o, and(2) melt-mixing the product of step (1) with an additional amount of polyethyleneterephthalate so as to attain a proportion of the ethylene naphthalatecomponent of from 5 to15 mole%.The present resin composition prepared by the process of the invention providesa bottle with excellent clarity even in a low transesterification ratio with which claritycould not be attained previously. This fact allows providing the present bottlewhich shows reduced resin degradation, and has an excellent resistance to heatand pressure and a reduced amount of thermal decomposition products. Also, acycle time is decreased and, therefore, bottle production in high-speed productionfacility is possible.Further, the present invention provides a process for preparing the resincomposition as well as a bottle therefrom that is improved over the above-10152025CA 02264857 1999-03-03mentioned composition in a resistance to heat and pressure, in a moldability and ina resistance at dropping.E“: .I. “E.Fig ‘l is a front view of an example of the self-standing bottle of the presentinvention. Fig.2 is an enlarged sectional view of the bottom part described in Fig.1.Fig. 3 is a bottom plan view of an example of the self-standing bottle of the presentinvention. Fig. 4 is a cross sectional view of an example of the preform.E..HE[|ElI.El B.: ..The present resin composition is characterized in that it comprises (A)polyethylene terephthalate and (B) polyethylene naphthalate in a proportion of theethylene naphthalate unit to a total of (A) and (B) of from 5 to 15 mole%, and has atransesterification ratio of 20% or less, or a cold crystallizing temperature,determined by differential scanning calorimetry, of 140°C or higher.Polyethylene terephthalate used in the invention is substantially linear and iscomposed mainly of units derived from terephthalic acid or ester derivatives thereofand ethylene glycol or ester derivatives thereof. The polyethylene terephthalatemay comprise units derived from other dicarboxylic acid and/or other dihydroxycompounds in a concentration of 10mole°/o or less. Dicarboxylic acids other thanterephthalic acid include aromatic dicarboxylic acids such as phthahlic acid,isophthahlic acid, naphthalenedicarboxylic acid, diphenylene dicarboxylic acid, anddiphenoxyethanedicarboxylic acid; aliphatic carboxyl acids such as adipic acid,sebacic acid, azelaic acid, decanedicarboxylic acid; alicyclic dicarboxylic acids10152025CA 02264857 1999-03-03such as cyclohexanedicarboxylic acid; and ester derivatives thereof.Dihydroxy compounds other than ethylene glycol include aliphatic glycols suchas trimethylene glycol, propylene glycol, tetramethylene glycol, neopntyl glycol,hexamethylene glycol, dodecamethylene glycol, diethylene glycol, triethyleneglycol, and tetraethylene glycol; alicyclic glycols such as cyclohexnedimethanol;aromatic diols such as bisphenols, hydroquinone, and 2,2-bis(4- ,3 -hydroxyethoxyphenyl) propane; and ester derivatives thereof.Polyethylene terephthalate used in the present invention preferably has anintrinsic viscosity [7] (determined at 30°C in a 1:1 volume blend of phenol andtetrachloroethane )of 0.6 to 1.2 (dl/g), more preferably of 0.7 to 0.9 (dl/g).Polyethylene naphthalate used in the present invention is composed mainly ofethylene naphthalate units derived from naphthalenedicarboxylic acid and ethyleneglycol. Naphthalenedicarboxylic acids include 2,6- naphthalenedicarboxylic acid,2,7- naphthalenedicarboxylic acid, 2,5- naphthalenedicarboxylic acid, and 1,4-naphthalenedicarboxylic acid, among which 2,6- naphthalenedicarboxylic acid ispreferred.The afore-mentioned polyethylene naphthalate may comprise ester units derivedfrom other dicarboxylic acids than naphthalenedicarboxylic acid and/or otherdihydroxy compounds than ethylene glycol in a concentration of 15 mole% or less,preferably 10 mole% or less, more preferably 8 mole% or less. The otherdicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid,isophthahlic acid, diphenyl dicarboxylic acid, and diphenoxyethanedicarboxylic acidas well as ester derivatives thereof. The other dihydroxy compounds includealiphatic glycols such as trimethylene glycol, propylene glycol, tetramethyleneglycol, neopntyl glycol, hexamethylene glycol, dodecamethylene glycol, diethyleneglycol, triethylene glycol, and tetraethylene glycol; alicyclic glycols such as10152025CA 02264857 1999-03-0310cyclohexnedimethanol; aromatic diols such as bisphenols, hydroquinone, and 2,2-bis(4- ,3 -hydroxyethoxyphenyl) propane; and ester derivatives thereof.The afore-mentioned other ester unit is preferably incorporated in a form of anaphthaiate coplyester polymer. Particularly, a copolyester polymer with ethyleneterephthalate is preferred. This is because such a coplyester polymer has amelting point closer to that of polyethylene terephthalate than a polyethylenenaphthaiate homopolymer and, therefore, is easily melt~kneaded with polyethyleneterephthalate. A content of the other ester unit in the copolyester is 15 mole% orless, preferably 10 mole% or less. Particularly preferred is a polyethyleneterephtha|ate—ethylene 2,6-dinaphthalate copolymer comprising 8 mole% of anethylene naphthaiate unit.Polyethylene naphthaiate used in the present invention preferably has anintrinsic viscosity [7] (determined at 30°C in a 1:1 volume blend of phenol and1,1 ,2_.2-tetrachloroethane )of 0.4 to 1.0 dl/g, more preferably of 0.4 to 0.8 dl/g.In the present invention, the transesterification ratio means ester interchangebetween polyethylene terephthalate and polyethylene naphthaiate, for which adetermination method will be described below. The transesterification ratio of thepresent resin composition is 20% or less. Even a composition with atransesterification ratio above 20% may provide a transparent bottle, if thecomposition has a cold crystallizing temperature of 140°C or higher. However, thetransesterification is preferably 20% or less, more preferably 18% or less, from thestandpoint of improving the mass-productivity and preventing the degradation ofthe resin.In the present invention, the cold crystallizing temperature is a crystallizing peaktemperature in a calorimetric curve obtained with a differential scanning calorimeter(DSC220, ex SEIKO Electronics Co.) at a temperature elevation rate of 10°C/min.10152025CA 02264857 1999-03-0311The cold crystallizing temperature of the present polyester resin composition is140°C or higher, preferably 140 to 160°C, more preferably 150 to 160°C. If thecold crystallizing temperature is lower than 140°C, clarity of the obtained bottle isbad, while it is practically difficult to obtain a resin composition having that above160°C.In the present invention, the resin composition having a transesterification ratio of20% or less and a cold crystallizing temperature of 140°C or higher is preferred.Such a resin composition not only provides transparent bottles suitable forbeverages but also has a mass—productivity adaptive to high-speed production. Theresin composition having such properties could not be obtained by conventionalmethods of blending polyethylene terephthalate with polyethylene naphthalate.Especially, it is one of the characteristics of the present resin composition that evenwhen the composition has a transesterification ratio of 20% or less, it provides atransparent bottle.E I E . : .. H . I I E . H lEresswzeIncidentally, further improvement is desired in resistance to heat and pressure ofa mouth and neck part of a bottle, since heat and pressure are concentrated on themouth and neck part in a hot filling and sterilizing step. To improve heatresistance, a method where a mouth and neck part is crystallized is commonlyused in polyethylene terephthalate biaxially stretched bottles, but is timeconsuming and leads to decrease in throughput. Another method is to increase aglass transition temperature of a raw material resin. In this method, a mouth andneck part of a bottle is not stretched, so that the resistance to heat and pressure ofthis part is mainly determined by the glass transition temperature (Tg) of the raw10152025CA 02264857 1999-03-0312material resin.To increase Tg, one may blend a larger amount of polyethylene naphthalatewhich has a higher Tg than polyethylene terephthalate. However, polyethylenenaphthalate is expensive. In addition, if the amount of polyethylene naphthalateexceeds 20 mole%, the crystallinity degreases to become unsuitable to biaxial-stretch blow molding. Accordingly, the solution by blending a larger amount ofpolyethylene naphthalate has the limitation.The present inventors have focused their consideration on a content of adiethylene glycol ester unit in polyethylene terephthalate as a factor affecting a Tgbesides the aforesaid blending ratio. The unit is derived from a reaction ofterephthalic acid or ester derivatives thereof with diethylene glycol or derivativesthereof. The present inventors have examined a relationship between the contentof the unit and a Tg of the resin to have found that a resin composition having ahigh Tg and an excellent resistance to heat deformation can be obtained by the useof a resin having a content of the unit at a certain level or below.That is, the present invention is a polyester resin composition prepared by melt-kneading (A) polyethylene terephthalate and (B) polyethylene naphthalate,characterized in thata. a proportion of the ethylene naphthalate unit to a total of (A) and (B) is from 5 to15 mole%,b. a transesterification ratio is 20% or less, and .c. a content of the diethylene glycol ester unit in (A) polyethylene terephthalate is1.5 mole% or less based on (A).Further, it is preferred that the content of the diethylene glycol ester unit in thepolyester resin composition is 1.5 mole°/o or less based on the total of (A) and (B).In the aforesaid resin composition, it is preferred that polyethylene terephthalate10152025CA 02264857 1999-03-0313does not comprise units derived from any other dicarboxylic acids and/or any otherdihydroxy compounds.In addition, the content of diethylene glycol ester unit in the polyethyleneterephthalate used in the invention should not exceed a certain level. The unit isformed in reactions of diethylene glycol, which is a bi-product in the production ofpolyethylene terephthalate, with terephthalic acid or derivatives thereof, and isconsidered to have the structure represented by the formula (1), Le. 2-ethyleneoxyethylene terephthalate residue. The present inventors have examineda relationship between a content of the unit and a Tg of a resin on variouspolyethylene terephthalate resins. As a result, the present inventors havesucceeded in realizing a higher Tg of a raw material polyester resin—blendcomposition by using polyethylene terephthalate having a content of the unit of 1.5mole% or less, preferably 1.4 mole% or less, without increasing the amount ofpolyethylene naphthalate to be blended, and thereby further improving theresistance to heat and pressure of a bottle.-0 oc CO--O-CH2CH2—O--CH2CH2—O (1)In the preparation of the present composition in the present invention, thecontent of the diethylene glycol ester unit is determined on every lot of polyethyleneterephthalate and those having the content of 1.5 mo|e°/o or less are used. Thecontent of the unit can be determined by, e.g., NMR spectrometry on proton peakscorresponding to the diethylene group of aromatic carboxylic acid diethylene glycolester, which will be described in details below.10152025CA 02264857 1999-03-0314The aforesaid polyethylene terephthalate has an intrinsic viscosity [:7 ] of 0.6 to1.2 (dl/g), more preferably of 0.7 to 0.9 (dl/g).As to polyethylene naphthalate used in the invention, what is described aboveregarding the resin composition applies here, too. Further, in the presentcomposition, the content of the diethylene glycol ester unit in a final product resincomposition is preferably 1.5 mole% or less, and accordingly the content of thediethylene glycol ester unit in the polyethylene naphthalate is preferably at a certainlevel or less. The diethylene glycol ester unit in the polyethylene naphthalate isconsidered to have a structure of the above-mentioned formula (1) with thebenzene ring being replaced by a naphthalene ring. In the copolymer withpolyethylene terephthalate the structure of formula (1) may also be included.Preferably, the content of the diethylene glycol ester unit in the polyethyleneterephthalate that is a base polymer of the present composition is 1.4 mole% orless, and the content of the diethylene glycol ester unit in the polyethylenenaphthalate is 2.0 mole% or less.A blend ratio of (A) polyethylene terephthalate with (B) polyethylene naphthalateis such that a proportion of the ethylene naphthalate unit to a total of (A) and (B) isfrom 5 to 15 mole%, preferably 7 to 13 mole°/o. If the content of the ethylenenaphthalate unit is blow the afore-mentioned lowest limit, heat resistance and a gasbarrier property of a bottle are insufficient. Meanwhile, If the content of theethylene naphthalate unit is above the afore-mentioned upper limit, a blend resincomposition loses the crystallizing property to cause problems. For example,pellets are fused and stick to each other during dehumidifying drying beforesecondary melt-molding, which is not desirable.10152025CA 02264857 1999-03-0315 The resin composition of the present invention is prepared in a form of pellets orthe like. Then, the resin composition of the present invention is molded into abottle preform by injection molding. The bottle preform is characterized in that itcomprises (A) polyethylene terephthalate and (B) polyethylene naphthalate in aproportion of the ethylene naphthalate unit to a total of (A) and (B) of from 5 to 15mole%, and has a transesterification ratio of 25% or less, or a cold crystallizingtemperature, determined by differential scanning calorimetry, of 140°C or higher.EolxesterjqmesOne embodiment of the polyester bottle of the present invention is a polyesterbottle characterized in that it comprises (A) polyethylene terephthalate and (B)polyethylene naphthalate in a proportion of the ethylene naphthalate unit to a totalof (A) and (B) of from 5 to 15 mole°/o, and has a haze at a barrel part of said bottleof 3% or less, and a content of acetaldehyde of 20ppm or less. The aforesaidpolyester bottle preferably has a transesterification ratio of 27% or less.The aforesaid bottle is characterized by superior clarity with a haze at a barrelpart of the bottle of 3% or less. Here, a haze is a value determined according toASTM D 1003, as will be described below.Thermal degradation of the raw material resin can be restrained as describedabove, and accordingly the aforesaid polyester bottle is characterized in that it hasan acetaldehyde content of 20ppm or less. Therefore, ingredients of beverages orthe like contained in the bottle are not deteriorated by acetaldehyde, and the tastesand aroma are preserved very well. The acetaldehyde content herein isdetermined by extracting a predetermined amount of finely divided pieces from abottle with distilled water and analyzing it by gas chromatography. The details will10152025CA 02264857 1999-03-0316described later in the specification.In the aforesaid bottle, the transesterification ratio is 27 % or less, preferably25 % or less. Although this transesterification ratio is lower than that previouslyrequired for clarity, the resin composition has excellent clarity. A resin compositionhaving a transesterification ratio above 27% may give a transparent bottle.However, a higher melt temperature or a longer melt time is required to attain sucha high transesterification ratio, so that problems arise in mass-productivity anddegradation of the resin or the like, and also the acetaldehyde content increases. Another embodiment of the bottle of the present invention is a plastic self-standing bottle prepared by biaxial-stretch blow molding, characterized in that thebottom part (1) of the bottle has a plurality of leg parts (2) extending below from ahemispherically curved bottom face (11) with the leg parts being disposed at anapproximately regular interval along the circumference of the bottom face, and thatsaid polyester resin bottle comprises a polyester resin composition comprising (A)polyethylene terephthalate and (B) polyethylene naphthalate in a proportion of theethylene naphthalate unit to a total of (A) and (B) of from 5 to 15 mole%, and havinga transesterification ratio of 5 to 30 °/o and an intrinsic viscosity of 0.70 dl/g or larger.In the bottle, it is preferred that a mouth and neck part and a central part of thebottom face (10) of said bottle are of a substantially noncrystalline state, and havea density of 1.330 to 1.3509/cm3. It is further preferred that a wall thickness in abarrel part of the bottle is 0.5mm or less or a weight per unit net internal volume ofthe bottle is 0.055 to 0.065g/ cma.The intrinsic viscosity for the afore-mentioned bottle is measured at 30 °C withan Ubbelohde's viscometer on samples prepared by dissolving 0.5 g of the10152025CA 02264857 1999-03-0317polyester resin cut from the self-standing bottle in 100 cc of a 1:1 volume blend ofphenol and 1,1,2,2-tetrachloroethane. The intrinsic viscosity of the resincomposition in the aforementioned self-standing bottle is 0.70 dl/g or larger,preferably 0.73 dl/g or larger. A bottle having an intrinsic viscosity below 0.70 dl/gmay have an uneven bottle wall thickness, particularly a thickness of a barrel partof a bottle is often thin and feels bad when held in a hand; and also such a bottlehaving an uneven wall thickness has very poor resistance to heat and pressurewhen subjected to heat sterilization treatment.The intrinsic viscosity usually becomes smaller than that of a raw materialpolyester resin composition because of thermal degradation of the resincomposition caused by the heating in a cylinder and shearing heat imposed by ascrew in a molding step. Therefore, to ensure that the intrinsic viscosity of theresin constituting the self-standing bottle be 0.7 dl/g or larger, a mixing ratio of (A)to (B) is preferably set so as to meet the inequality: (an intrinsic viscosity of (A) xwt% of (A) + an intrinsic viscosity of (B) x wt°/o of (B))/100>0.7, preferably >0.75,provided that the intrinsic viscosity of (A) and that of (B) are in the rangesmentioned for the resin composition.The transesterification ratio of the polyester resin composition constituting thebottle is 5 to 30 °/o, preferably 7 to 25 °/o. A resin composition having atransesterification ratio above 30 °/o may provide a bottle with good clarity.However, a higher melt temperature or a longer melt time is required to attain sucha high transesterification ratio, so that the problems may occur in, for instance,mass-productivity and degradation of the resin; and also change in a barreldiameter of a bottle after heat sterilization treatment tends to increase.in the aforesaid self-standing bottle, it is preferred that a mouth and neck partand a centeral part of the bottom face of said bottle are of a substantially10152025CA 02264857 1999-03-0318noncrystalline state, and have a density of 1.330 to 1.350g/cm3. As used herein,the terms "substantially noncrystalline state" mean that the bottle is clear in visualobservation, and no cloudy part due to crystallization can be noticed. The presentbottle is characterized in that, even if the mouth and neck part and the other are ofthe substantially noncrystalline states, it shows less deformation in heat sterilization.Since one can save a clouding crystallization treatment which is conventionallypracticed on a mouth and neck part to prevent deformation in heat sterilization, theproductivity of the bottle is improved. In addition, the clarity of the mouth and neckpart gives a refreshing appearance to the bottle, which is suitable for soft drinks.Herein, the density of the mouth and neck part and the cental part of the bottomface are determined by a density gradient method, which will be described in detaillater in the specification. The density is 1.330 to 1.350 g/cm"’, preferably 1.336 to1.340 g/cm3. If it is higher than 1.350 g/cm3 , a cloudy part formed by crystallizationis noticeable in visual observation.Further, the self-standing bottle preferably has a bottle wall thickness at a barrelpart of 0.5 mm or less. Here, the barrel part is a part other than the mouth andneck part and the bottom part, and is indicated by numeral 12 in Fig. 1 which showsan example of the self-standing bottle of the present invention. Especially, it ischaracteristic to the present bottle that, even when the wall thickness of the upperend portion (20) of the curved surface of the bottom part immediately below thebarrel part in Fig. 1 is 0.5mm or less, the present bottle shows little change in shapeby heat sterilization.Further, the self-standing bottle preferably has a weight per unit net internalvolume of 0.055 to 0.065g/ cm'‘‘. The wall thickness of the present self-standingbottle can be thin as described above and, hence, a weight per unit net internalvolume ca be small. For example, it is possible to make a’ bottle of 500ml in net10152025CA 02264857 1999-03-0319internal volume having about 30.5g in weight.E . 3 . . | E E E . B I II EThe present resin composition may be prepared by weighing (A) polyethyleneterephthalate and (B) polyethylene naphthalate individually, for instance, in a formof pellets in a proportion of (B) polyethylene naphthalate of from 5 to 15 mole%,and then melt-kneading them at a temperature of a melting point of the resinmixture or higher with a kneading extruder. The kneading extruder is preferablyprovided with a degassing device, such as a twin-screw extruder with vents.Polyethylene terephthalate and polyethylene naphthalate are preferably dried inadvance, but they can be melt-kneaded with a kneading extruder having ventswithout being dried. The temperature in the melt kneading is set to a temperatureof the melting point of the resin mixture or higher, e.g., 290 to 330°C of a resintemperature. The resin is kneaded and extruded in a ratio of the extruder outputrate to a screw rotation speed of from 0.1 to 1.4 kg/hr-rpm, preferably 0.4 to 1.2kg/hr-rpm. If the ratio is lower than the afore-mentioned lower limit, a largeramount of heat is caused on the resin by a strong shear force of the extruder, whichcauses undesirable degradation of the resin. in addition, mass-productivity isworsened because of the decrease in the extruder throughput. On the other hand,if the ratio exceeds 1.4, the resins cannot disperse homogeneously each other andclarity of the composition is worse. If the average residence time of the resin isprolonged by decreasing the extruder throughput to improve the dispersion of theresin, problems arise, such as decrease in the mass-productivity. The resincomposition obtained is usually molded into a form of pellets.The afore-mentioned polyester resin composition may comprise various kinds ofadditives such as stabilizers against weathering, pigments and dyes as far as the10152025CA 02264857 1999-03-0320objects of the present invention are not damaged.Subsequently, the obtained pellets are heated in air at 110 to 130°C for 2 to 4hours to crystallize at least the surface of the pellets, and dehumidified and dried at140 to 160°C for 3 to 6 hours to lower the water content, usually, to be 50ppm orless. The dried pellets are fed to a conventional injection molding machine andmelt-injection molded into preforms. The molding temperature is the melting pointof the resin plus 5 to 40°C, preferably p|us10 to 20°C. If the molding temperatureis lower than the melting point of the resin plus 5°C, a melt viscosity is too high toinjection-mold the resin easily. If it is higher than the melting point plus 40°C, theamount of thermal decomposition products, e.g., acetaldehyde, increases whichmay degrade the quality of the bottle for beverages.An injection molding machine used in the present invention is preferably providedwith vents, which has a high kneading effect and is capable of removing the thermaldecomposition products such as acetaldehyde by sucking them out under areduced pressure or vacuum, but any conventional injection molding machine maybe used. When the average residence time of the resin is 40 to 240 seconds,preferably 90 to 180 seconds, with an IJD of about 20 to 25,it is possible to obtainpreforms having good clarity and an acetaldehyde content of 20 ppm or less.The intrinsic viscosity becomes usually lower than that of the raw materialpolyester resin composition due to degradation of the resin composition caused bythe heating in a cylinder and heat generated by shear force on the resin passingthe screw in a molding step. Therefore, to prevent the intrinsic viscosity of thepreform from becoming lower than 0.7 dl/g , it is preferred to mix (A) polyethyleneterephthalate with (B) polyethylene naphthalate in the ratio already described forthe self-standing bottle and take care to avoid that the cylinder temperature is toohigh compared with the melting point of the resin composition and that the cycle10152025CA 02264857 1999-03-0321time is too large.The cylinder temperature of an injection molding machine is preferably 290°C orlower, more preferably 280°C or lower. The molding cycle time per preform ispreferably 40 seconds or shorter, more preferably 30 seconds or shorter. Mostpreferably, the cylinder temperature is 280°C or lower and the cycle time perpreform is 30 seconds or shorter.The preform obtained is biaxial-stretch blow molded into a self-standing bottle.As to a stretch ratio in the stretch molding, a circumferential stretch ratio is 3.7 to4.3 and a longitudinal stretch ratio is 2.7 to 3.3. Preferably the circumferentialstretch ratio is 3.9 to 4.1 and the longitudinal stretch ratio is 2.8 to 3.1. If thestretch ratios are higher than the above values, a wall of the bottle becomes so thinthat the resistance to heat and pressure is worse or the bottle bursts during themolding. On the other hand, if the stretch ratios are lower than the above values,non-stretched portions remain, for example, in a bottom part. Especially in a non-stretched in a bottom part, thermal creeping phenomenon takes place on accountof a rise in pressure inside the bottle in heat sterilization, which causes the wholecentral part of the bottom to swell out, and hence the bottle loses self-standingcapability.In the invention, the circumferential stretch ratio and the longitudinal stretch ratioare defined by the following equations:circumferential stretch ratio = an outer diameter of a barrel of a bottle / an outerdiameter of a barrel of a preform, andlongitudinal stretch ratio = a length below a neck to a bottom of a bottle / a lengthbelow a neck to a bottom of a preform.Herein, the outer diameter of a barrel of a preform means a diameter of the partindicated by numeral 31 in Fig.4; the length below a neck to a bottom of a preform10152025CA 02264857 1999-03-0322means a length of the pan indicated by numeral 33 in Fig.4; and the length below aneck to a bottom of a bottle means a length from the lowest end of a neck to a tip ofa leg of a self-standing bottle.The temperature of a preform subjected to biaxial-stretch blow molding ispreferably 90 to 100°C. Such a temperature can be realized by, for example,heating the preform with an infrared-heating medium located in parallel with thelongitudinal axis of the preform. If the temperature of a preform is not in the afore-mentioned range, it is difficult to obtain a bottle with even wall thickness, so thatresistance to heat and pressure of the obtained bottles tend to be worse. fijlIn another embodiment of the process for the preparation of the bottles accordingto the nvention, an improved method for preparing a bottle is provided which issuperior in bottle moldability and a resistance at dropping. in a first step of theprocess, polyethylene terephthalate and polyethylene naphthalate are melt-mixedin a proportion of the ethylene naphthalate component to a total of them of 20 to 50mole%. Then, the product of the first step is mixed with an additional amount ofpolyethylene terephthalate so as to attain a proportion of the ethylene naphthalatecomponent of from 5 to15 mo|e°/o. Thus, degradation of polyethylene terephthalatecan be decreased by preparing the resin composition having larger content ofethylene naphthalate by the melt-mixing in the first step, and mixing with anadditional amount of ethylene naphthalate. An intrinsic viscosity of polyethyleneterephthalate is higher than that of polyethylene naphthalate, so that a resincomposition having a higher intrinsic viscosity and a better moldability can beobtained finally. The improved moldability eliminates unevenness of the wallthickness in the molded article, thereby providing a bottle which is superior in a10152025CA 02264857 1999-03-0323resistance to heat and pressure as well as gas barrier property, and resistance atdropping.The proportion of the ethylene naphthalate component in the first step is 20 to 50mole°/o, preferably 20 to 45 mole%. If the ethylene naphthalate proportion is lowerthan the above lower limit, the amount of the polyethylene terephthalate to beadded in the second step becomes smaller, so that it becomes difficult to attain ahigh intrinsic viscosity. On the other hand, if the ethylene naphthalate proportionis higher than the above upper limit, phase separation may occur in the secondstep, resulting in poor clarity of the resin.The melt-mixing in the first step is performed in such a way that polyethyleneterephthalate and polyethylene naphthalate are weighed individually, for instance,in the form of pellets, and melt-mixed with each other at a temperature of at leastthe melting point of the resin mixture with a kneading extruder. The kneadingextruder is preferably provided with a degassing device, e.g., a twin-screw extruderwith vents. The temperature of the melt-mixing is set to a temperature of at leastthe melting point of the resin mixture, for example, a resin temperature at an exit ofthe extruder of 250 to 320°C. Preferably, the afore-mentioned temperature is 260to 290°C. By the melt-kneading at such a relatively low temperature, a resincomposition having higher clarity can be obtained. The extrusion conditions areas already mentioned above. The resin composition obtained has an intrinsicviscosity of 0.55 to 0.69 dl/g and is transparent. The composition is molded, forinstance, into a form of pellets. Then, the pellets are dried in air at 110 to 130°Cfor 2 to 4 hours to crystallize at least the surface layer and then dehumidifying-driedat 140 to 160°C for 3 to 6 hours. Thus, the water content of the pellets can bemade 50 ppm or less.in the second step, the dried pellets and an additional amount of polyethylene10152025CA 02264857 1999-03-0324terephthalate are mixed so as to attain a proportion of the ethylene naphthalatecomponent of from 5 to15 mole%. The mixing may be carried out with variousconventional means such as an injection molding machine, a blender, a mixer, andan extruder. Preferably, the mixing is conducted by feeding both of the pellets witha constant weight feeder to an injection molding machine to form a preform.An injection molding machine used in the present invention is preferably providedwith vents, which has a high kneading effect and is capable of removing thermaldecomposition products such as acetaldehyde by sucking them out under areduced pressure or vacuum, but any conventional injection molding machine maybe used. An average resin residence time and bottle moldability are the same asalready described above.ExamplesThe present invention will be further explained in the following examples.9 E I E . 3 ..Exa_mple_A-.1Polyethylene terephthalate ( intrinsic viscosity 0.85 dl/g ) and a copolymer( intrinsic viscosity 0.62 dl/g ), as the polyethylene naphthalate, consisting of 92mo|e°/o of an ethylene-2,6-naphthalene dicarboxylate unit and 8 mole °/o of anethylene terephthalate unit were fed at a constant weight rate in a weight ratio of 90to 10 into a corotating twin-screw extruder TEX 65 ( ex Nihon Seikosho Co.,screw diameter 65mm, L/D=42 ), and extruded into resin pellets under the mixingconditions that an extruder output rate was 250kg/hr, and a ratio of the extruderoutput rate to a screw rotation speed was 1Ø The pellets showed atransesterification ratio of 18% and a cold crystallizing temperature of 152.7°C.10152025CA 02264857 1999-03-0325Then, the pellets thus obtained were molded into preforrns of 31 g in weight with aninjection molding machine P50 ( ex Krupp Former Plast GmbH., 3.50 tons ) , whichwere then blow molded into bottles of 500ml in net internal volume with a blowmolding machine LBO1E( ex Krupp Corpoplast GmbH). The obtained bottles weretransparent. The temperature of the preforrns immediately before the moldingwas about 100‘C.Exam.Qle_A-2Resin pellets were molded under the same conditions as in Example A-1 exceptthat the extruder output rate was 200 kg/hr. The pellets showed atransesterification ratio of 9.5%, and a cold crystallizing temperature of 155'C. Then,bottles of 500ml in net internal volume, were obtained in the same manner as inExample A-1 which were transparent.Exam,ole_A_-.3 "Resin pellets having a transesterification ratio of 15%, and a cold crystallizingtemperature of 154"Cwere obtained under the same mixing conditions as inExample A-2 except that the ratio of an extruder output rate to a screw rotationspeed was 0.4. Then, transparent bottles of 500ml in net internal volume wereobtained in the same manner as in Example A-2. fiResin pellets were obtained under the same conditions as in Example A-1 exceptthat the ratio of an extruder output rate to a screw rotation speed was 1.8. Then,bottles of 500ml in net internal volume were obtained as in Example A-1. Thepellets molded under those mixing conditions showed a cold crystallizing10152025CA 02264857 1999-03-0326temperature of 133C and the bottles obtained therefrom were not transparent, butcloudy. mmfiA2Resin pellets were obtained under the same mixing conditions as in Example A-2 except that the ratio of an extruder output rate to a screw rotation speed was 1.8and then, bottles of 500ml in net internal volume were obtained as in Example A-2.The pellets molded under those mixing conditions showed a cold crystallizingtemperature of 134.2 C and the obtained bottles were not transparent, buttranslucent.mm Pellets of polyethylene terephthalate ( intrinsic viscosity 0.85 dl/g ) and pellets ofa copolymer ( intrinsic viscosity 0.62 dl/g ), as the polyethylene naphthalate,consisting of 92 mole% of an ethylene-2,6-naphthalene dicarboxylate unit and 8mole °/o of an ethylene terephthalate unit were homogeneously mixed with eachother in a weight ratio of 90 to 10 and dried at 150C for 6 hrs. Then, the mixturewas molded into preforms of 31 g in weight with an injection molding machine P50(ex Krupp Former Plast GmbH., 350 tons), which were subsequently blow moldedinto bottles of 500ml in net internal volume with a blow molding machine LB01 E 50( ex Krupp Corpoplast GmbH). Here, the average residence time was 210seconds, which was shorter than that conventionally required to producetransparent bottles solely with an injection molding machine, so that transparentbottles could not be obtained because of the insufficient mixing.The results obtained above are summarized in Table 1. Comparing theCA 02264857 1999-03-0327Examples and the Comparative Examples in Table 1, all the bottles obtained fromthe resin composition according to the present invention are superior in clarity withlower haze. Also, whereas it has been considered that a resin composition failsto give a transparent bottle unless it has a significantly high transesterification ratioand that its cold crystallizing temperature cannot be 140°C or higher, the resincomposition according to the present invention is characterized in that it gives abottle with superior transparency even in a high-speed production despite that ithas a transesterification ratio of 20% or lower, and also in that a cold crystallizingtemperature is 140°C or more.CA 02264857 1999-03-032832m AZinc S=o?§.§_<_o_a3c 0:65 B~m\ ><m$cm ._._.m:m- Ooa _::._:m_o woamBwozsm 0:65 moaméaofimzoz fimmamsom mmfimzzomzos o.<m$_=~__.6 <.moom:< _..m~m_uo_<m.3<_m:m _uo_<m3<_m:m mnmma Ego o2:m Bzo 83om$.Em.m$u3:m_m6 :mc_..3m_w.m :6}; e6>:.63v qmmiwmop 3 29 8.3: 2%moaméxammaiomxm3u_m >-H mo 5 $552 mmo . mm 5 Gun ofim o.mmoaméxammainmxw3U_m >-m mo 3 93.52 moo 4 mm am am cum» onmoqmérsmmaiomxmzim >-w 8 8 93,52 moo ox 8 Am ._wA PER cummoaiOoafimzmoz xammaiomxm3b_mH 8 3 $552 mmo em 8 m am oumm somofimsOo3cm1mo: xzmmaiumxm3m_m m 8 3 $352 moo 5 mm m Gab oumm Pm_:_mo._o:Ooaumzmoz Boaim.mxmnimw 8 3 Smozsm So - No on am ofim mm10152025CA 02264857 1999-03-0329The intrinsic viscosity, transesterification ratio, and cold crystallizing temperatureof the polyester resin composition or pellet in the above Examples and ComparisonExamples, and the haze of the drawing blown bottles were determined by thefollowing methods.I..”..The intrinsic Viscosity was measured at 30 °C with an Ubbelohde's viscometeron samples prepared by dissolving 0.5 g of the polyester resin in 100 cc of amixture of phenol and 1,1,2,2-tetrachloroethane of a 1:1 volume ratio.I .t. . B .An appropriate amount of a sample was dissolved in a 1:1 volume blend oftrifluoroacetic acid and chloroform, to which tetramethylsilane was added as areference. Proton NMR spectra were taken on the solution with an FT-NMFispectrometer (ex JEOL) to obtain the integrated intensities of the proton peakscharacteristic of the naphthalate-ethylene-terephthalate bond, naphthalate-ethylene-naphthalate bond, and terephthaIate- ethylene-terephthalate bond, fromwhich the abundance ratio of each bond was calculated. The conversion wascalculated from the abundance ratios according to the following equation :%TE(transesterification ratio)=(NET_obs)/(NET__calc) x 100(%)(NET_obs )2 ratio of naphthalate-ethylene-terephthalate bond(NEN_obs): ratio of naphthalate-ethylene-naphthalate bond(NET_ca|c): 2N(1-N)N (mole fraction of naphthalate component): (NEN_obs)+(NET_obs )/23”: ”.. IAbout 10mg of the resin was weighed in an Al pan and analyzed with a10152025CA 02264857 1999-03-0330differential calorimeter DSC22OC (ex SEIKO Electronics Co., calibrated with In)using a vacant Al pan as a reference at a temperature increase rate of 10°C/min.The crystallizing peak temperature was read from the obtained calorimetry cun/e.B_Qt1la_l:lazeA sample piece of 3 cm x 3cm was cut from the barrel part of the molded bottle,which was analyzed with a differential color meter 2 80 (ex Nihon DenshokuKogyo Co.) according to ASTM D 1003.EE.: ..H.l “IE.(1) The intrinsic viscosity and the diethyleneglycol ester unit content of the resinsused in the Examples are as follows;polyethylene terephthalate:a. Example B-1 and Comparison Examples B-1 and B-2intrinsic viscosity, 0.83 (dl/g),diethyleneglycol ester unit, 1.3 mole%,b. Reference Example B-1intrinsic viscosity, 0.83 (dl/g),diethyleneglycol ester unit, 1.7 mole%,c. Reference Example B-2 and Comparison Example B-3intrinsic viscosity, 0.83 (dl/g),diethyleneglycol ester unit, 3.2 mole%,polyethylene naphthalate: coplymer consisting of 92 mole% of an ethylene-2.6-naphthalene dlcarboxylate unit and 8 mole% of an ethylene terephthalate unit,intrinsic viscosity 0.50 (dl/g)diethyleneglycol ester unit, 1.8 mole%10152025CA 02264857 1999-03-0331(2) Preparation of the Resin Compositions «ExamplL=_&1The polyethylene terephthalate and the polyethylene naphthalate specifiedabove were fed in a constant weight rate in a ratio of 85 wt% to 15 wt% (ethylenenaphthalate unit, 11.4 mole °/o) into a corotating twin-screw extruder TEX 65 (ex.Nihon Seikosho Co., screw diameter 65mm, UD=42 ), and molded into blendpellets under the mixing conditions that an extruder output rate was 250kg/hr, and aratio of the extruder output rate to a screw rotation speed was 0.9. mBfiBlend pellets were obtained under the same melt-mixing conditions as inExample B-1 except that polyethylene terephthalate containing 1.7 mole% of adiethylene glycol ester unit was used. eB£Blend pellets were obtained under the same melt-mixing conditions as inExample B-1 except that polyethylene terephthalate containing 3.2 mole% of adiethylene glycol ester unit was used. Polyethylene terephthalate and polyethylene naphthalate, which were the sameas those used in Example B-1, were fed at a constant weight rate in a weight ratioof 85 wt% to 15 wt% into a corotating twin-screw extruder TEX 65 (ex NihonSeikosho Co., screw diameter 65mm, L/D=42 ), and molded into pe||ets'having atransesterification ratio of 28.2% under the mixing conditions that an extruderoutput rate was 250kg/hr, and a ratio of the extruder output rate to a screw rotation10152025CA 02264857 1999-03-0332speed was 0.09. Polyethylene terephthalate and polyethylene naphthalate, which resins were thesame as those used in Example B-1, were fed at a constant weight rate in a weightratio of 70 wt% to 30 wt°/o ( ethylene naphthalate 23.6 mole"/o) into a corotatingtwin-screw extruder model TEX 65 (ex Nihon Seikosho Co., screw diameter65mm, lJD=42 ) and molded into blend pellets under the mixing conditions that anextruder output rate was 250kg/hr, and a ratio of the extruder output rate to a screwrotation speed was 0.9.mm Polyethylene terephthalate, which was the same as that used in ReferenceExample B-2, was fed at a constant weight rate in a weight ratio of 70 wt% to 30wt% ( ethylene naphthalate 23.6 mo|e°/o) into a corotating twin-screw extruder TEX65 (ex Nihon Seikosho Co., screw diameter 65mm, L/D=42 ), and molded intoblend pellets under the mixing conditions that an extruder output rate was 250kg/hr,and a ratio of extruder output rate to a screw rotation speed was 0.9.(3) Measurement of the resin composition propertiesThe glass transition temperature, intrinsic viscosity, transesterification ratio, anddiethylene glycol ester unit content of the pellets prepared in the aforesaidconditions were measured. The measurement methods for the intrinsic viscosityand transesterification ratio were as described above, and those for the glasstransition temperature and diethylene glycol ester unit content were as will bedescribed below. . .75,10152025CA 02264857 1999-03-0333El . .The glass transition temperature was determined from charts obtained at atemperature elevation rate of 10'C/min with a differential scanning calorimeterDSC220C (ex SEIKO Electronics Co.).E. I I I I .Proton NMR spectra were obtained in the same manner as in thetransesterification ratio measurement. The ratio of the integrated intensity of thepeak around 4.84 ppm originated from the protons in the ethylene terephthalateunit to those of the peaks around 4.20 ppm and 4.70 ppm originated from theprotons in the diethylene group in the diethylene glycol ester terephthalate unit wasdetermined, from which a diethylene glycol ester terephthalate unit content wascalculated.(4) Measurement of the heat resistance of the resin compositionsFurther, the heat resistance of the resin compositions was determined on testpieces cut from a sheet of 2mm x 110mm made from each blend pellets by injectionmolding with an injection molding machine SH-15OA(ex Sumitomo Heavy IndustryCo.) at a cylinder temperature of 280°C.Tan 8 peak temperature in viscoelasticitvA 12cm-wide test piece was prepared from the sheet. With a viscoelasticitymeter RDA2(ex Reometrix Co. ) , a viscoelasticity was measured on the test pieceunder the following conditions to determine a tan 8 peak temperature.Temperature elevation rate : 2°C/min from 23°C to 130°CFrequency: 1OHz twist10152025CA 02264857 1999-03-03 A 2mm-wide test piece was prepared from the aforesaid injection molded eheet.With a tensile teet inetmment with a constant rnioroloed (ex INTESOO Co.). adeformation ratio wee measured.Teet pieoe: 2mmx2mrnx6ommLLoad : zokglcm‘ .Temperature program : 4'CImin from SOC to 85C held at 65CDetonnetion retio : measured after aomln at 65C(5) Preparation and evaluation of polyester bottlesPreterm: of 319 in weight were molded from each of the aforesaid blend pellets‘ with an injection molding machine SH-15OA(ex Surnitomo Heavy industry Co.) at acylinder temperature of_280‘C. After re-heated to 110C, the preform was moldedinto a bottle of 500 ml in net internal volume with a blow molding machine LB-01E(ex Krupp Corpo Pleat GmbH). The bottle was evaluated for moidabiiity andsubjected to a hot water filling test as described below. ' ’A bottle was filled with hot water of 85C and capped. After left for 3 minutee,the bottle wee by water. The intemei diameter of the mouth part wasmeasured with a micrometer and the ratio of change in the diameter. comparedwith the original lntemel diameter. was determined._The appearance of ‘each 5 bottles prepared under the aforesaid conditions wasvisueiiy observed immediately after the blow molding. A case, where all the 5CA 02264857 1999-03-0335bottles had the shape honestly conforming to the mold and stood upright, was ratedas "O " ; a case where even one of the bottles leaned was rated as "A"; and acase, where bottle failed apparently to honestly reproduce the shape of the moldwas rated as " >< ".The results of the above evaluations are as shown in Table 2.CA 02264857 1999-03-0336._.md_m m:92 3m.m2m_ _<_. _omom. N oo:..m23 3m ..m<< 3m8_._m_Zinc 8:0Emaama um__m. uaumammImm. qmmwaanmUm.o..3m=o: Z05: woamimam- 863m $833.0: 5 c._.3:9 c.:o_o\& ?So\ov _< Umom $§:§:_o: ._.o Sam no:m$2 B20 aw 3o m :28:83 . 83umBE$ . .8:0 3_o..o_oma 2:3 8:68:m__m 8m» 2 madvo_<m.:<_m:m_uo_<m.:<_m:m no_<m3<_m:m Uo_<m§<_m:m vo_<m=.<_m:m .m$u:.:m_m.m\ .. o . . o omxm3u_m .m3uZ:m_m.m :mn:3m_m8 ..m_.mu:3m_m:m :mu3:m_m$ _oo_<m3<_m:m 3:9 A325 A5 A3 A3 CL Ax;:mn:3m_m:mmx. w; 0.8 cm flu 5 82¢ can _.A Nm 8.» 8m cam .98 Oma.mx.w-_ 98 cm ...\. em 83. cum 5 3; may 8.. row .23 Omm..mx.m-m 98 om mm em mmxm on» No .2.» mew «Kb #3 .m.mo OOo3u.mx.m._ 98 om 5 5 mm: m on» .5 mm.» awe Sm ouo .98 xOo3n.mx.m-m 98 om 5 _.m 35o 98 em _m.m man om.» o.mm -98 xOo3u.mx.m-m 98 om an em 35¢ 98 No 5.0 mwo So 93 -o.mm x* _ H _:3:w.o <rmoow=<“Tm”D_m.:<_m:m o_<oo_ mmnmfi cs:10152025CA 02264857 1999-03-0337Compared to Reference Examples B-1 and B-2, the resin composition ofExample B-1 has higher Tg and tan 8 peak temperatures and has a lessdeformation ratio in the constant-microload tensile test and a less mouth sizechange ratio in the 85°C water-filled bottle, and thus is superior in heat resistance.in Reference Example B-1, the same resin was used as that in Example B-1 and,however, the moldability is bad, because the resin was kneaded till thetransesterification ratio became higher, resulting in degradation of the crystallinityof the resin. On the other hand, the resin composition of Example B-1 according tothe present invention shows not only good moldabiliy but also good clarity despitethe low transesterification ratio of 7.3%, and has a shorter manufacture cycle time.In Comparison example B-2, the polyethylene naphthalate content was higher.The resin has higher Tg, but shows a low intrinsic viscosity, resulting in poormoldability. Also in Comparison Example B-3, the polyethylene naphthalatecontent was higher. However, the resin shows a Tg similar with that in B-1 becauseof the higher diethylene glycol ester terephthalate unit, and also shows poormoldability.C.._E.r.e.f.O.lIfl.SE Polyethylene terephthalate ( intrinsic viscosity 0.85 dl/g ) and the copolymer( intrinsic viscosity 0.62 dl/g ), as the polyethylene naphthalate, consisting of 92mole% of an ethylene-2,6-naphthalene dicarboxylate unit and 8 mole °/o of anethylene terephthalate unit were fed at a constant weight rate in a weight ratio of 90wt% to 10 wt% into a corotating twin-screw extruder TEX 65 ( ex Nihon SeikoshoCo., screw diameter 65mm, L/D=42 ), and molded into resin pellets under themixing conditions that an extruder output rate was 200kg/hr, and a ratio of the10152025CA 02264857 1999-03-0338extruder output rate to a screw rotation speed was 1Ø The cold crystallizingtemperature of the pellets was 155°C. Then, the resin pellets were crystallized witha stirring dehumidifying drier Challenger Mini(ex Kawata Co.) at 120°C for 4 hours,and further dried at 150"C for 6 hours with a dehumidifying drier(ex Matsui Co.).Then, the dried pellets were molded into preforms of 31 g in weight with an injectionmolding machine P50 ( ex Krupp Former Plast GmbH., 350 tons). The preform wastransparent despite the low transesterification ratio of 7.6% and the content ofacetaldehyde, which is a blproduct, in the constituent resin was 11.6ppm. Theaverage residence time in the injection molding machine was 210 seconds. Thepreform was blow molded with a blow molding machine LB01E ( ex. KruppCorpoplast GmbH) at a drawing temperature of 100°C to obtain transparentbottles of 500ml in net internal volume.The bottle had excellent clarity with a hazeof the bottle at 0.3 mm thickness of 0.39%.E.xam,c2l.e.C_-2Resin pellets were prepared under the same conditions as in Example C-1except that the extruder output rate was 250kg/hr. The cold crystallizingtemperature of the obtained pellets was 152.7°C. Next, preforms were prepared inthe same manner as in Example C-1. The preform was transparent, and had atransesterification ratio of 10% and an acetaldehyde content of 12.5ppm. Thendrawing blown bottles of 500ml in net internal volume were molded in the samemanner as in Example C-1, which bottles were transparent with a haze of 0.46%.Examnle_Q;3Preforrns were prepared in the same manner as in example C-1 except that thepreform molding temperature was 295°C. The preform was transparent and had a10152025CA 02264857 1999-03-0339little higher acetaldehyde content of 23ppm. Then, drawing blown bottles of 500mlin net internal volume were molded in the same manner as in Example C-1, whichbottles were transparent with a haze of 0.61%.C_QmnaLi§on_Example_C_-1Resin pellets were prepared in the same manner as in Example C-2 except thatthe ratio of the extruder output rate to a screw rotation speed was 1.8. The coldcrystallizing temperature of the obtained pellets was 133°C. Next, preforms wereprepared in the same manner as in Example C-1, except that the moldingtemperature was 280°C. The preform was cloudy and opaque and the bottle of500ml in net internal volume obtained by drawing blow molding under the sameconditions as in Example C-1 was cloudy with a haze of 7.87%. Pellets of polyethylene terephthalate ( intrinsic viscosity 0.85 dl/g ) and pellets ofa copolymer ( intrinsic viscosity 0.62 dl/g ), as the polyethylene naphthalate,consisting of 92 mole°/o of an ethylene-2,6-naphthalene dicarboxylate unit and 8mole % of an ethylene terephthalate unit were homogeneously mixed with eachother in a weight ratio of 90vvt% to 10wt°/o and dried at 150C for 6 hrs. Then,preforms of 31 g in weight were prepared with an injection molding machine P50(ex Krupp Former Plast GmbH., 350 tons) at a molding temperature of 290°C withan average residence time of 210 seconds. The preform was not transparent andhad a transesterification ratio of 9.2%. Using the preform, bottles of 500ml in netinternal volume were drawing blow molded under the same conditions as inExample C-1. The bottle was cloudy with a haze of 10%.101520CA 02264857 1999-03-0340 mmPreforms were prepared in the same manner as in Comparison Example C-2except that the molding temperature was 310 ‘C . The preform had atransesterification ratio of 24.5% and was transparent. However, theacetoaldehyde content of the preform was 40.4ppm, which was too high for thebeverage bottle application. Bottles obtained by drawing blow molding the preformunder the same conditions as in Example C-1 showed a haze of 0.58%.An acetaldehyde content was measured in the following manner. 1From the mouth part of the preform, 5.0 g of a sample was cut. The sample wasextracted with 10 ml of distilled water at 160°C. After 2 hours of the extraction,about 1 ml of ethanol was added and analyzed for an acetaldehyde content by gaschromatography. GC conditions are as follows:Gas chromatography unit : model GC7A (ex Shimadzu Seisakusho Co.)Column : PEG-6000(3.2 mm x 1.6 m)column temperature 105°Cinjection temperature 220°Cdetector temperature 220°Ccarrier gas nitrogen, 200kPa, splitlessinjection volume 2 ,1 l.The results are as shown in Table 3.CA 02264857 1999-03-034132¢ w_u_,m3:.: 3o_Q__.6_<:x.:m B20 930$ Em__m~ 3o_a_:Pno:aEo:m oozaaozmOo_a059: $8\ ><mSmm Q<m$__E:omoqmi Smamaom 83nmS:=m ><mSom imam- >09.83:0: mam 3 um__m~m Zoaiu amamsom mmfimamomzos Sismmo m_am3am moamEmé 3m_m1m_ 0:65 mcmma 820 o. .mm_: $3umB:.:m 23¢ ammo <_moom=< oosnma :m~mEo_<m5<_m:m Uo_<m.:<_m:m ?o\:_.V :6\:163V Ammop 29 we Ammo; £3 3:8 €93 fix:.m$E::w_ma :mn:.:w_w8mx.O; mo 40 Emmi Um__m. moo A on am mmo M. o Nm 9.3 :.m 98mx.o-m mo A o Emmi nmzmfi mmo _ 8 any mmo M. o 3 oumm so 93mx.O-_ mo 8 Emmi _um__m~ moo E on am mom ,3 o 5 oumm mm 0.3O03?mx.O-. mo .0 Emmi Um__m. mmo em 8 am Bo M3 w oumm Emb 2:Conan.mx.o-m mo 3 0.60. Ema - - - - moo B o mm oumm mom. 3.»02.6. .mx.O-m mo 4 o 0.69 U_m:a - - - - Bo Bo M3 33 .5.» cum10152025CA 02264857 1999-03-0342D. Polyester Resin BottlesExamnLesDA_to_D_-3Pellets of polyethylene terephthalate ( intrinsic viscosity 0.83 dl/g ) and pelletsof a copolymer ( intrinsic viscosity 0.62 dl/g ), as the polyethylene naphthalate,consisting of 92 mole% of an ethylene-2,6-naphthalene dicarboxylate unit and 8mole % of an ethylene terephthalate unit were fed in an twin-screw extruder withoutdrying, model TEX -65 a ( ex Nihon Seikosho Co., L/D=42, 3 vents) at aconstant weight rate in the weight ratio specified in Table 1, and melt extruded at aratio of the extruder output rate to a screw rotation speed of 1.0 kg/hr- rpm to obtainpellets having an ethylene-2,6-dinaphthalate unit of 7.6 to13.8 mole%. Thetemperature of the molten resin was 300°C, and the residence time of the moltenresin was 1.5 minutes. Then, preforms of 31 g in weight with a maximum wallthickness of 4.0 mm were prepared from the pellets with an injection moldingmachine SH150A ( ex Sumitomo Heavy Industry, L/D=25 ). The temperature ofthe molten resin was 270°C in Examples D-1 and D-2, and 290°C in Example D-3 ,and the residence time of the molten resin was 3.5 minutes in Examples 1 to 3.From the preforms, bottles of 500ml in net internal volume were drawing blowmolded with a blow molding machine LB01 E ( ex. Krupp Corpoplast GmbH). emBottles of 500ml in net internal volume were prepared in the same manner as inExamples D-1 and 2 except that the pellets were mixed so that the ethylene-2,6-dinaphthalate unit was 3.7 mole%.The aforesaid pellets of polyethylene terephthalate and the aforesaid pellets of10CA 02264857 1999-03-0343polyethylene naphthalate were homogeneously mixed so that the ethylene-2,6-dinaphthalate unit was 7.6 mole%. Following dehumidifying drying, the mixedpellets were directly introduced to an injection molding machine SH15OA ( exSumitomo Heavy Machine Industry) without advance melt kneading to moldpreforms of 31 g in weight with a maximum wall thickness of 4.0 mm. Theresidence time of the molten resin were 3.8 minutes in Comparison Example D-2,10.7 min in Comparison Example D-3 and 13.0 min in Comparison Example D-4,and the temperature of the molten resin was 280°C in all of these ComparisonExamples. These preforms were drawing blow molded into bottles of 500ml in netinternal volume with a blow molding machine LBO1 E ( ex. Crup Foamer Plast Co.).Table 4 shows the results of the evaluation on the transesterification ratio,acetaldehyde content, haze, and heat and pressure resistance of the obtainedbottles.CA 02264857 1999-03-0344was A_<=x3c 8:0 ?S.o\ov moam two mémmimam- Imm: mmmfimzmomaos Emmmcqmm3<_m:m B20 ImNm >om6_Qm:<am Emimsom_uo_<m5<_m:m .uo_<m=.<_m:m :mv:3m_m8 :3 Ao\ov 8382 $3.m$_u:3m_m8 :mu:§m_m:m ::_23o_.o\ov €23mxm:6_m 0; mo 5 Na 3 Pm 5 wmxm3o_m 0-» mm 3 am 8 on 3 wemxm3n_m o-m mo 3 Na 2 o.m E EOo3Um2mo:mxm3n_m U; 8 m mu m ow 2 mm.Oozfimamozmxm3u_m O.» mo 8 Na 3 PM 3 -Ooanmimosmxm3u_m ca 8 8 Na E on 3 mOozfimzmozmxm3n_m O.» we 3 sm 3 .1 mm mm10152025CA 02264857 1999-03-0345Bottles of Examples D-1,D-2 and D-3 had excellent clarity with a haze of 0.6-0.7% even though they had a low transesterification ratios of 11 to 24%. Also theyhad a low acetaldehyde content and a low change ratio of the whole volume of 2.9to 3.1 % and is suitable for the beverage bottle application. On the other hand, thebottle in Comparison Example D-1 showed a large change ratio of the wholevolume of 6.5% and poor resistance to heat and pressure, because of the lowethylene naphthalate unit content. In Comparison Examples D-2 to D-4, bottleswere blow molded from the preforms obtained by injection molding directly withoutadvance melt kneading. The bottle of Comparison Example D-2 showed poorclarity, which is considerably due to lack of melting. The bottles of ComparisonExamples D-3 and D-4 showed better clarity because of the longer residence timethan that of Comparison Example D-2. However, the acetaldehyde content washigher, and therefore the bottles are not suitable for the beverage bottle application.Further, it is seen from the comparison of Example D-1 and Comparison ExampleD-2 that the bottles of the present invention are characteristically clear even with alower transesterification ratio.The acetaldehyde content and resistance to heat and pressure were measuredas follows. EmFive grams of a sample cut from a bottle was finely divided, and was extractedwith 10ml of distilled water at 160°C for 2 hours. After the extraction, about 1 ml ofethanol was added and analyzed for an acetaldehyde content by gaschromatography as described above. &A bottle was filled with a carbonated water of 2.5 gas volume at 5°C and capped.10152025CA 02264857 1999-03-0346The bottle was then sprayed by warm water at 66°C for 22 min. The ratio of changeof the whole volume of the bottle before and after the spraying was determined.Here, the terms “ gas volume” means the ratio of the volume of the dissolvedcarbon dioxide gas at a pressure of 1 atm at 20°C to the volume of water. The ratioof change in the whole volume was determined according to the following equation.Ratio of change in the whole volume =(the whole volume after heating - thewhole volume before heating) x 100/ the whole volume before heatingPellets of polyethylene terephthalate ( intrinsic viscosity 0.83 dl/g ) and pellets ofa copolymer ( intrinsic viscosity 0.65 dl/g ), as the polyethylene naphthalate,consisting of 92 mole°/o of an ethylene-2,6-naphthalene dicarboxylate unit and 8mole °/o of an ethylene terephthalate unit were fed in a twin-screw extruder withoutdrying, TEX 65 a ( ex Nihon Seikosho Co., L/D=42, 3 vents) at a constant weightrate and melt kneaded at a ratio of the extruder output rate to a screw rotationspeed of 1.0 kg/hr - rpm to obtain resin pellets having the ethylene-2,6-dinaphthalate unit of 5 to 15 mole°/o. The temperature of the molten resin was300°C, and the residence time of the molten resin was 1.5 minutes. Afterdehumidifying-dried, the pellets were fed to an injection molding machine SH150A( ex Sumitomo Heavy Industry, L/D=25 ) to prepare preforms, which weighed 30.5g.The preforms were blaxial-drawing blow molded into bottles of 500ml in netinternal volume as shown in Fig. 1 with a blow molding machine LB01E (ex. KruppCorpoplast GmbH), wherein the temperature of the barrel part of the mold was85°C and that of the bottom part was 20°C.Fig.2 shows an enlarged sectionalview of the bottom part and Fig.3 shows a bottom plan view.10152025CA 02264857 1999-03-0347mm Bottles of 500 ml in net internal volume were prepared in the same manner as inExamples E-1, E-2 and E-3 except that the content of the ethylene-2,6-naphthalenedicarboxylate unit was 2 mole%.Bottles of 500 ml in net internal volume were prepared in the same manner as inExamples E-1, E-2 and E-3 except that resin pellets or preforms having theethylene-2,6—naphthalene dicarboxylate unit of 7.6 mo|e°/o were preparedaccording to the molding conditions shown in Table 6.Bottles of 500 ml in net internal volume were prepared in the same manner as inExamples F-1 to -3 except that resin pellets or preforms having the ethylene-2,6-naphthalene dicarboxylate unit of 7.6 mole% were prepared according to themolding conditions shown in Table 7.The following methods were used to determine a density, etc., and to evaluate theobtained bottles.D_en;~2i1;LA density was determined on samples cut from a mouth and neck part of a bottleand from the center of a bottom with a n-heptane-carbon tetrachloride densitygradient column at 20°C.10152025CA 02264857 1999-03-0348WalubicknessA wall thickness of a bottle was determined by measuring a wall thickness of fourcircumferential points of each part of a bottle by a micrometer and averaging them.E III I I I .I.Appearance of each 5 bottles in each of the Examples and ComparisonExamples immediately after the biaxial-streching blow molding process wasvisually observed. When a bottle, showed a shape honestly conforming to themold, stood uprightly on a flat surface, and was transparent throughout the bottle, itwas rated as "O "; when a bottle leaned on a flat surface, it was rated as "A";and a bottle, failed apparently to reproduce theshape of the mold, it was rated as "X II.:I . II. .I..A bottle was filled with carbonated water of 2.5 gas volume at 5°C and capped.The bottle was then sprayed by warm water at 70°C for 30 min. The appearanceafter the spraying was visually observed. A bottle, which showed no or littlechange in the appearance and stood upright was rated as "O "; a bottle whichstood upright but showed appreciable appearance change was rated as "A"; anda bottle which changed apparently in shape and could not stand by itself was ratedas As used herein, the term s“ gas volume" mean a ratio of the volume ofdissolved carbon dioxide gas at a pressure of 1 atm at 20°C to the volume of water.:I .I I. II II I .A diameter of a barrel part of a bottle was measured on each 5 bottles after theafore-mentioned heating treatment to determine the ratio of change. A bottle with aCA 02264857 1999-03-0349change of 2.5% or less was rated as "O " ; a bottle with a change of 2.5 - 3.5%was rated as "A" ; and a bottle with a change above 3.5% was rated as " >< As can be seen from Table 5, the bottle in Comparison Example E-1, of whichethylene naphthalate content was as low as 2 mole%, deformed largely after theheat sterilization treatment and lost the self-standing capability due to thedefonnation in the leg parts. On the other hand, the bottles in Examples E-1, E-2and E-3, of which ethylene naphthalate contents were 5 to 15 mole%, showed goodmoldabillty, little deformation by the heating sterilization treatment to have asuperior resistance to heat and pressure.CA 02264857 1999-03-0350fimzm mmxm3n_mm-. mxm3v_mm-m mxm3u_mm-w Oo3vmiwo:mxm3u_mm-_m3<_m:m :m6_.::m_m.8 3o_ .5 m 5 :1. moo3vo:m2.3m:mmmHm:.._om:o: Ego 3 mo do 3. mm.3338 <_moom:< 26 P3 cum can 98Um:m:< m” m 39:: E25“ 58 Sam 58 53m zmox um:Um:m:< E m 3:03 omimq Roam Sum 53 58 Summoam 3oEmE_:< O O O O>numm_,m:om mama smmfima D O O Xwm:.m_ Q5322 O O O Xosmznm mama xmmfimaCA 02264857 1999-03-0351Amzm mmxm-» mx.m-m mx.m-m Ooau. Oo3_u.mx.m-m mx.m-wU2mxzcamq amx-m,nE amxamu amxamn +mx-mmn Ewanwas 0.“oc€S 8.8 .8Emmi mofimé Saaoanm__m» mnmma xc\:163 co _ A T. .4.m39mE$3 30:2. 89: so moo wow woo Sm I_<_o:m: $9:qmmamaom 23¢ mmo 8 am So am :_<_o_am« mx-ao> mm; mo> m:-_mo> m_+ao> m_+_mo>_u$..o3,. 282m: 89:Smamsom =3m mmo 8 8 8 8 PSm.3<_m:m :mu:3m_m.Booanosmi 3o_ 8 3 3 Ho 3 Nafimsmmmfimzmomaoz Ego .3 m _ o mm .. 9°._31:m_o <_woom:< E6 of ca 3» 93 9.3Um:m:< B m 39:: mzmox Um: Q03» 58 ‘bum Sum 83 $3Dm:m:< m. m co:o3 omima m\o3.o. 33 53 Sum _ 8m 5%._.:.o_3mmm 9. um: mo 33 ex 93 93 E5 93woam 3o_amu__:< O O O O O>EummE:om 942 zmmfimu D O O D Dwm_._.m_ Emamfimq nrmzmmmam. smmaq O O O D x10CA 02264857 1999-03-0352As shown in Table 6, the bottle in Comparison Example E-2 having a lowtransesterification ratio showed large changes in appearance and in a barreldiameter after the heat sterilization treatment. Meanwhile, the bottle inComparison Example E-3 having a high transesterification ratio of 32% showedlarge change in a barrel diameter after the heat sterilization treatment. Also, asseen from Table 7, the bottle in Comparison Example E-4 having a low intrinsicviscosity of 0.63 dl/g was worse in moldability to have uneven thickness andshowed poor resistance to heat and pressure..On the other hand, all the bottles inExamples from E-4 to E-10 having transesterification ratios of 5-30 and intrinsicviscosities of 0.70 dl/g or more showed good moldability, and little deformation bythe heat sterilization treatment to have superior resistance to heat and pressure.CA 02264857 1999-03-035AmU_m .\.O03?mx.m-u mx.m-m mx.m-o mx.m-3 mxm-»02 ozmxicamw ._.mx-mm Q amxam Q 29a amx-mm Q Ewanmmzo 2oc.8S B8 .8 _Am\:163 eo _.o I 3 cmmo$<< 35:0:Emmi mvmmaumzm. 4m3uSE«m3 30.5: $9: 00 woo wow u wow wow_<_o:m: 6,9:fimmimzom 23¢ mmo gm on u 8 M8_<_o_am1 m:«ao> mi; ,n.o> m:-ao> m:-_ mo> mm; mo>v«m3a3 _<_o:m: 8m_:Smamsom Sam mmo 8 8 B o 8 8m3<_m:m :mc:.3m_m8oo3uo:m3 30. .5 3 E 3 3 Nafimzmmmfizmomaos $20 .3 I 8 8 B 3_:3:m.o <.moom:< as of 3m 3» 9: 98Um:m:< m.“ m 39:: m8% um: Q03“ 38 Z8 2.8 #8.‘ $3Um:m:< mm m canon. omimfi m\o3w C3 33 Sam 2.8 Sum4.:.o_Smmm 3 um: mo 33 9.8 9%. 9.8 O3 9%mega 3o_qmE_:< O O O O x>vnmm«m:om mama smmfima O O O O Dmm2m_ a_m3m~m« ozmzmmmama smmflmq O O O O D10152025CA 02264857 1999-03-0354 Pellets of polyethylene terephthalate ( intrinsic viscosity 0.83 dl/g ) and pellets ofa copolymer ( intrinsic viscosity 0.61 dl/g ), as the polyethylene naphthalate,consisting of 92 mole% of an ethylene-2,6-naphthalene dicarboxylate unit and 8mole % of an ethylene terephthalate unit were fed into a corotating twin-screwextruder, TEX -65 a ( ex Nihon Seikosho Co., L/D=42, 3 vents, without drying )at an constant weight rate and melt extruded into resin pellets having anethylene-2,6-dinaphthalete unit of 7.6 mole% at a ratio of the extruder output to ascrew rotation speed of 1Ø The temperature of the molten resin was 300C andthe residence time of the molten resin was 1.5minutes. After dried, the pellets werefed to an injection molding machine SH15OA (ex Sumitomo Heavy Industry,L/D=25 ) to prepare a preform as shown in Fig.4 with the cylinder temperature andthe cycle time per preform shown in Table 1. The preforms were biaxial-stretchingblow molded into bottles of 500ml in net internal volume as shown in Fig. 1 with ablow molding machine LB01E ( ex. Krupp Corpoplast GmbH) in a circumferenrtialstretch ratio of 2.95 and a longitudinal stretch ratio of 4.13 in all of the Examples 1to 3. Fig.2 is an enlarged sectional view of the bottom part and Fig.3 is a bottomplan view. 'Examnlesl=_—4_ans:l_E;5Bottles of 500 ml in net internal volume were prepared in the same manner as inExamples F-1, F-2 and F-3 except that the intrinsic viscosity of the preform wasO.763d|/g, the cylinder temperature was 280C and the cycle time per preform was40sec, and the stretch ratios were set as shown in Table 9.Bottles of 500 ml in net internal volume were prepared in the same manner as in10152025CA 02264857 1999-03-0355Examples F-1, F-2 and F-3 except that the cylinder temperature was 300°C andthe cycle time per preform was 50 sec or 60 sec.Bottles of 500 ml in net internal volume were prepared in the same manner as inExamples F-4 and F-5 except that the stretch ratios were set as shown in Table 9.The obtained bottles were evaluated for the resistance to heat and pressure,change in appearance, mass distribution, and bottle moldability. mA bottle was filled with carbonated water of 2.5 gas volume at 5°C and capped.The bottle was then sprayed by warm water at 66°C for 22 min. The ratio of changein the whole volume of the bottle was determined. Here, the terms “ gas volume”mean a ratio of the volume of dissolved carbon dioxide gas at a pressure of 1 atmat 20°C to the volume of water. A bottle which showed the ratio of change in thewhole volume of 2.5% or less was rated as "O"; a bottle with the ratio of 2.5-3.5 %,as "A"; and a bottle with the ratio exceeding 3.5%, as " X Qhana9_in_aI2D.eaLance_The appearance after the aforesaid heat treatment was visually observed. Abottle which showed no or little change in the appearance and stood upright wasrated as "O " ; a bottle which stood upright but showed appreciable change in theappearance was rated as "A"; and a bottle which changed apparently in shapeand could not stand by itself was rated as " >< I I I. .I .The barrel part of the bottle specified by numeral "3" in Fig 1 was cut andweighed. The ratio of the weight to the total weight of the bottle was determined.10CA 02264857 1999-03-0356E III I I I .I.The appearance of the bottle immediately after the biaxial-streching blow moldingwas visually observed. When a bottle showed the shape conforming honestly tothe mold, stood upright on a flat surface, and was transparent throughout the bottle,it was rated as "O "; when a bottle leaned or had a cloudy part, it was rated as "A; and when a bottle failed apparently to reproduce the shape of the mold orimpossible to be molded, it was rated as " >< ".Each ten bottles of each of the Examples and the Comparison Examples wererated in all the evaluations above and the ratings were averaged. The results ofExamples F-1 to F-3, and Comparison Example F-1 and F-2 are as shown in Table8, and the results of Examples F-4 and F-5 and Comparison Examples F-3 to F-5are as shown in Table 9. In the overall rating , "O " means " excellent", "A"means "good" and " >< " means " poor".CA 02264857 1999-03-0357._.mU_m mOoan. Oo3u.min; min-» mx.m-m min; min-»m.3<_m:m :mv:§m_m8 ooauosmi C30. oi S S No 3 amzoasm o<_:a2 63vm$E«m A08 N8 M8 Bo use Sooozaaosm O<o_m 23¢. man. 3 mo 8 8 8_:3:m_o <wmoom:< 3 E962: ESQ 38 9:5 38. 980 93¢woam 85. <<m.m3 EV Sm mom Sm wow mom_.u.m:m_ <<mE_.._» SV 3 mo 3 3 so_wm:m_ Ego Q; 2.. Ba mwm ES mac<<:o_m <o_c3m osmzmm Sac Gov O D D x x>E.mmE:om m:m_. zmmfima O O D x xO<mS__ $28 0 D D x xCA 02264857 1999-03-03584mu_m mO03? O03?mx._u-n mivm mx._u-w mifln Oo3n.mx._u-mm3<_m:m :mn:3m_mnm ooauozmzn n3o_ «go No .\..m No Nm NmO:o:3+m«m::m_ £88: Sac N8 mom mom man 93_.o:m_.Ea_:m_ mzmas Ego n.mm now non mnw New_<_oa5o o<_:am1m3u2mnSm A09 moo moo moo mmo mmono:o:_o:m O<o_m :39 mmo. no no no no no_:.=._:m_o <_moom:< 9. 383:: REV oumm 38 oumw 38 38woam 3o_omu=:< O O D D x<<:o_m <o_:3m ormzom Sac Qwv O O x D _3uomm_Em no m<m_:m_m>mbmm=m:om mnmfi 38:3 0 O x x _3vomm.Em no m<m_:mnmO<m_.m__ «maze O O x x x10152025CA 02264857 1999-03-0359As can be seen from Table 8, the barrel weight decreases with the decreasingintrinsic viscosity of a preform. The bottles from a preform having an Intrinsicviscosity oi 0.70di/g or more ( Examples F-1 to F-3) felt good when held in a handand stood upright steadily on a fist urtace. On the other hand. when the intrinsicviscosity was less than 0.70 dl/9 (Comparison Examples F-1 and F-2), the wallthickness and weldtt oi the barrel were smaller, and the touch was worse when_ held in a hand. Also the bottles showed a cloudy portion, which is not good inappearance.As’ to the resistance to heat and pressure and the change in appearance, theratio of change in whole volume and the defamation at the bottle increased withthe decreasing Intrinsic viscosity oi‘ a preform as shown in Table 8. because thebottle swelled in the radial and longitudinal directions more easily. The bottles inExamples F-1 and F-2. swelled in the bottom parts by the heat treatment in theevaluation of resistance to heat and pressure and could not stand by themselves.‘Meanwhile, the bottles in Examples F-1 to F-3 were excellent in the resistance toheat and pressure and showed little change in appearance.It can seen from Table 9 that the bottles with superior capability and stability ofupright-standing could be obtained when the circumferential stretch ratio was from3.7 to 4.3 and the longitudinal stretch ratio was from 2.7Vto 3.3 (Examples F4 andF-5), Those bottles were good also in the resistance to heat and ‘pressure. incontrast. the bottle in Comparison Example F-3, where the longitudinal etnetch ratiowas less than 2.7 and the circumferential stretch ratio was bigger than 4.3, had anon-stretched portion in the bottle and was poor in moldablilty. in the evaluation ofthe resistance to heat and pressure. the bottle iege changed the shape to lose theself-standing capability and the change in the whole volume was greater than thatin Examples F-4 and F-6. The bottles in Comparison Exarnplas F4 and F-6.10152025CA 02264857 1999-03-0360where the longitudinal stretch ratio was greater than 3.3, showed a non-stretchedportion and a cloudy portion and were poor in moldability. Especially, no bottle inComparison Example F-5 could be molded. The bottle in Comparison Example F-4 was inferior in the resistance to heat and pressure to the bottles in Examples 4and 5. Exam.ole_G-_1Polyethylene terephthalate ( intrinsic viscosity 0.83 dl/g ) and a copolymer( intrinsic viscosity 0.50 dl/g ) consisting of 92 mole% of an ethyIene-2,6-naphthalene dicarboxylate unit and 8 mole % of an ethylene terephthalate unitwere fed into a corotating twin-screw extruder TEX -65 ( ex Nihon Seikosho Co.,screw diameter 65mm, UD=42) at a constant weight rate in a weight ratio of 70wt% to 30wt% and molded into kneaded pellets. Then, the kneaded pellets weremixed with the same polyethylene terephthalate in a 50% to 50% weight ratio, andmolded into preforms of 31g in weight with an injection molding machine P50 ( exKrupp Former Plast GmbH., 350 tons) , and then blow molded with a blow moldingmachine LB01 E ( ex. Krupp Corpoplast Plast Corp.) to obtain transparent bottle of500ml in net internal volume. The temperature of the preform immediately beforethe blow molding was about 100 °C.Kneaded pellets were prepared in the same manner as in Example G-1 exceptthat the polyethylene terephthalate and the polyethylene naphthalate copolymerwere mixed in the weight ratios listed in the second column of Table 10. Then, thekneaded pellets were mixed with the polyethylene terephthalate in the weight ratiosCA 02264857 1999-03-0361shown in the fourth column of Table 10 to obtain bottles of 500ml in net internalvolume.CA 02264857 1999-03-0362._.mc_m 5_sm=-3_x.:o S=o?».\..v m3<_m:m m.m=m. _<__x.:n $20 ?$..\& m.3.§$ w 2. _< mesa353.835 932%: :mu:3m_m$ _< eamozoa 3oE.:nV :mE::m_m.m o m moam :m~m mmmismom_oo_<m€_m:m _uo.<m=.<_m:m :3: Ego E V §$a8_ vo_<m€.m:m :3: 8:0 3:9 3o_%g__2 Q; m. a6u_u_:m88u:=.m_m.m :mu3:m_m8 .3o_m..\& o um=m. 68u:.:m_m8 ::o_mo\&mxw3u_m_ 3 mo Ba pad mo mo :.m 0.1 A O o.m Omxm3u_mm mo 3 mm.» 98m 8 mo :.m ofl: O on Omxm3v_mw mo mo xi .w cam» 8 3 :3. ours O on» Omm.ma=8 mo mo :1 38 3 8 S.» 98» x 9% xmxm:b_m.mmaaaom mm a :.m 9: a so o :.m oamw x oum xlmxm3m_mm.uo_<m.:<_m:m:moZ:m_w8ooaumamos a mm :.m 38 0 mm Dmxm3c_m10152025CA 02264857 1999-03-0363C9mi2azison_ExamnleInto an injection molding machine model P50 (ex Krupp Former Plast GmbH.,350 tons ) , 85wt% of polyethylene terephthalate and 15 wt°/o of a polyethylenenaphthalate copolymer were directly fed without being molded into kneaded pelletsin advance, and molded into a preform of 31g in weight. Then, a bottle of 500ml innet internal volume was prepared as in Example G-1.The results of evaluation are as shown in Table 10. As seen from Table 10, all ofthe resins in Examples G-1 to G-3 according to the present invention are superiorto those of Reference Examples G-1 and G-2 in moldability to give bottles havingcontours conforming to the mold. None of the bottles were broken in a drop test,which is another evidence of the superior moldability. Further, all of the bottlesaccording to the invention have good transparency with the haze of 0.8 or lower.Meanwhile, the bottle of the Comparison Example has a high haze and is notsuitable for the beverage bottle application. The clarity of the bottle may beimproved with an elongated melting time, which in turn makes the high-speedproduction of bottles impractical. Here, the resistance at dropping wasdetermined as follows.E . l .This test was performed on each 10 bottles from each Example. Twenty fourhours after the molding the bottle was filled with carbonate water of 4.0 gas volume,and kept at 5°C for 24 hours, and then dropped from a 2.0 m height with the bottompart being down. In table 10, a case where none of the 10 bottles was broken wasrated as "O", and a case where even one bottle was broken was rated as " X Field of the industrial ApplicationAs described above, the resin composition and the bottles therefrom according toCA 02264857 1999-03-0364the invention are suitable for the beverage bottle application and the presentprocess for preparing the bottle can be advantageously practiced in high-speedproduction facility.

Claims (24)

Claims

1. A process for preparing a polyester resin composition, characterized by melt-kneading (A) polyethylene terephthalate with (B) polyethylene naphthalate in a proportion of the ethylene naphthalate unit to a total of (A) and (B) of from 5 to 15 mole% with a kneading extruder in a ratio of an extruder output rate to a screw rotation speed of 0.1 to 1.4kg/hr-rpm.

2. A polyester resin composition comprising (A) polyethylene terephthalate and (B) polyethylene naphthalate, characterized in that a proportion of the ethylenenaphthalate unit to a total of (A) and (B) is from 5 to 15 mole%, and that a transesterification ratio is 20% or less, or a cold crystallizing temperature, determined by differential scanning calorimetry, is 140°C or higher.

3. A polyester resin composition prepared by melt-kneading (A) polyethylene terephthalate and (B) polyethylene naphthalate, characterized in that (a) a proportion of the ethylene naphthalate unit to a total of (A) and (B) is from 5 to 15 mole%, (b) a transesterification ratio is 20% or less, and (c) a content of the diethylene glycol ester unit in (A) polyethylene terephthalate is 1.5 mole% or less based on (A).

4. The polyester resin composition according to claim 3, wherein the content of the diethylene glycol ester unit is 1.5 mole% or less based on the total of (A) and (B)

5. The polyester resin composition according to any one of claims 2-4, wherein (B) polyethylene naphthalate comprises an ester component or components other than the ethylene naphthalate component in a proportion of 15 mole% or less.

6. The polyester resin composition according to any one of claims 2-5, wherein (B) polyethylene naphthalate comprises an ester component or components other than the ethylene naphthalate component in a proportion of 8 mole% or less.

7. The polyester resin composition according to any one of claims 2-6, wherein (B) polyethylene naphthalate is polyethylene 2,6-naphthalene dicarboxylate.

8. The polyester resin composition according to any one of claims 2-7, wherein said composition is molded in a form of pellets.

9. A polyester resin preform prepared by injection molding the polyester resin composition described in any one of claims 2-8.

10. A polyester resin bottle, characterized in that said bottle comprises (A) polyethylene terephthalate and (B) polyethylene naphthalate in a proportion of the ethylene naphthalate unit to a total of (A) and (B) of from 5 to 15 mole%, that a haze at a barrel part of said bottle is 3% or less, and that a content ofacetaldehyde is 20ppm or less.

11. The polyester resin bottle according to claim 10, wherein a transesterification ratio of the polyester resin is 27% or less.

12. A polyester self-standing bottle prepared by biaxial-stretch blow molding, characterized in that the bottom part of said bottle has a plurality of leg parts extending below from a hemispherically curved bottom face with said leg parts being disposed at an approximately regular interval along the circumference of the bottom face, and that said polyester resin bottle comprises a polyester resin composition comprising (A) polyethylene terephthalate and (B) polyethylene naphthalate in a proportion of the ethylene naphthalate unit to a total of (A) and (B) of from 5 to 15 mole%, and having a transesterification ratio of 5 to 30 %
and an intrinsic viscosity of 0.70 dl/g or larger.

13. The self-standing bottle according to claim 12, wherein a mouth and neck part and a center part of the bottom face of said self-standing bottle are of a substantially noncrystalline state, and have a density of 1.330 to 1.350g/cm3.

14. The self-standing bottle according to claim 12 or 13, wherein a wall thickness in a barrel part of said bottle is 0.5mm or less or a weight per unit net internal volume of said bottle is 0.055 to 0.065g/ cm3.

15. The bottle according to any one of claims 10-14, wherein (B) polyethylene naphthalate comprises an ester component or components other than the ethylene naphthalate component in a proportion of 15 mole% or less.

16. The bottle according to any one of claims 10-15, wherein (B)polyethylene naphthalate comprises an ester component or components other than the ethylene naphthalate component in a proportion of 8 mole% or less.

17. The bottle according to any one of claims 10-16, wherein (B) polyethylene naphthalate is polyethylene 2,6-naphthalene dicarboxylate.

18. A process for preparing a self-standing bottle comprising a step of biaxial-stretch blow molding a preform in a circumferential stretch ratio of 3.7 to 4.3 and a longitudinal stretch ratio of 2.7 to 3.3, characterized in that said preform comprises a polyester resin composition comprising (A) polyethylene terephthalate and (B) polyethylene naphthalate in a proportion of the ethylene naphthalate unit to a total of (A) and (B) of from 5 to 15 mole%, and having an intrinsic viscosity of 0.70 dl/g or larger.

19. A process for preparing a polyester bottle from a polyester resin composition comprising polyethylene terephthalate and polyethylene naphthalate, characterized in that use is made of a resin composition prepared by steps of (1)melt-mixing polyethylene terephthalate and polyethylene naphthalate in a proportion of the ethylene naphthalate component to a total of the polyethylene terephthalate and the polyethylene naphthalate of 20 to 50 mole%, and (2)melt-mixing the product of step (1 ) with an additional amount of polyethylene terephthalate so as to attain a proportion of the ethylene naphthalate component of from 5 to 15 mole%.

20. The process for preparing a polyester bottle according to claim 19, wherein a preform is prepared by injection molding in step (2).

21. The process for preparing a polyester bottle according to any one of claims 18-20, wherein the polyethylene naphthalate comprises an ester component or components other than the ethylene naphthalate component in a proportion of 15 mole% or less.

22. The process for preparing a polyester bottle according to any one of claims 18-21, wherein the polyethylene naphthalate comprises an ester component or components other than the ethylene naphthalate component in a proportion of 8 mole% or less..

23. The process for preparing a polyester bottle according to any one of claims 18-22, wherein the polyethylene naphthalate is polyethylene 2,6-naphthalene dicarboxylate.

24. A polyester resin composition obtained by step (1) of any one of claims 19-23, wherein the proportion of the ethylene naphthalate unit to the total of the polyethylene terephthalate and the polyethylene naphthalate is from 20 to 50 mole%, and the intrinsic viscosity is from 0.55 to 0.69 dl/g.