WO1999061514A1 - Procede de production d'une preforme de polymere thermoplastique et article ainsi produit - Google Patents

Procede de production d'une preforme de polymere thermoplastique et article ainsi produit Download PDF

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Publication number
WO1999061514A1
WO1999061514A1 PCT/US1999/011659 US9911659W WO9961514A1 WO 1999061514 A1 WO1999061514 A1 WO 1999061514A1 US 9911659 W US9911659 W US 9911659W WO 9961514 A1 WO9961514 A1 WO 9961514A1
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WO
WIPO (PCT)
Prior art keywords
thermoplastic polymer
container
preform
finish
reheat rate
Prior art date
Application number
PCT/US1999/011659
Other languages
English (en)
Inventor
David Paul Fischer
Lavonna Suzanne Buehrig
Original Assignee
Eastman Chemical Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eastman Chemical Company filed Critical Eastman Chemical Company
Priority to CA002332984A priority Critical patent/CA2332984A1/fr
Priority to BR9910709-0A priority patent/BR9910709A/pt
Priority to EP99925890A priority patent/EP1082377A1/fr
Priority to JP2000550911A priority patent/JP2002516204A/ja
Publication of WO1999061514A1 publication Critical patent/WO1999061514A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/08—Metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
    • B29C71/0063—After-treatment of articles without altering their shape; Apparatus therefor for changing crystallisation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/04—Carbon
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2949/00—Indexing scheme relating to blow-moulding
    • B29C2949/07—Preforms or parisons characterised by their configuration
    • B29C2949/0715—Preforms or parisons characterised by their configuration the preform having one end closed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
    • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
    • B29C49/06—Injection blow-moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
    • B29C71/02—Thermal after-treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/25—Solid
    • B29K2105/253—Preform
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0037—Other properties
    • B29K2995/0041—Crystalline
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C08K2003/2265—Oxides; Hydroxides of metals of iron
    • C08K2003/2272—Ferric oxide (Fe2O3)

Definitions

  • the present invention relates generally to the field of processing thermoplastic polymers and forming thermoplastic articles, and more particularly to a method of crystallizing a thermoplastic polymer by introducing a reheat rate- increasing additive into the thermoplastic polymer and processing same.
  • compositions particularly compositions comprising poly(ethylene terephthalate) or copolymers thereof (hereinafter collectively referred to as "PET"), for example in the form of films, bottles and other containers is well known.
  • PET poly(ethylene terephthalate) or copolymers thereof
  • container- forming compositions in the form of polymer chips or pellets, are usually formed into the container shape in a two stage process. First, a container preform is injection molded; and second, either immediately or after a short storage period, the container preform is blown using compressed air into a mold which is in the final shape of the container.
  • the container preform In the second stage of the process, the container preform is usually at or near ambient temperature, and it has to be heated to a temperature (for PET) of from about 85 °C to about 120°C for the blow molding step. It is this "reheat" step which is usually the rate-determining step in the second stage of the process.
  • known energy-absorbing materials have been added to polymer compositions to increase the "reheat" rate of the polymer preform to be processed and made into a container.
  • Tg glass transition temperature
  • the output of the container-forming processes is increased and less energy is required when using reheat rate-increasing additives. Examples of such known energy-absorbing materials or reheat rate-increasing additives and compositions containing same are illustrated in U.S. Patents 4,408,004; 4,476,272; 4,535,118; 4,420,581; 5,419,936; and 5,529,744.
  • Thermoplastic polymers are often heat-treated to modify their material characteristics for improved performance when forming thermoplastic articles.
  • the finishes i.e., the upper portion typically comprising an opening and threads for engaging a cap
  • the finishes are commonly crystallized by heating the finish of the preform, typically by exposure to infrared (ER.) radiation.
  • ER. infrared
  • the purpose of subjecting heat-set preforms to this process known as the Yoshino Process (U.S. Patent 5,261,545), is to convert the amorphous material in this region of the container to crystalline form, and thereby prevent or reduce distortion of the finish of the heat-set container during hot filling.
  • an injection-molded preform is placed in a carrier which shields the body of the preform against exposure to crystallizing heat, but leaves the finishes exposed.
  • the carrier containing the preform passes through an oven, where the preform finish is exposed to infrared energy for a sufficient amount of time to allow the finish to highly crystallize.
  • High crystallinity provides dimensional stability to the finish and allows the resulting article or container to be hot-filled without suffering from thermal distortion in the finish.
  • crystallizing a thermoplastic polymer preform is an additional step in the conventional container-forming process.
  • An additional step creates longer and less efficient processing.
  • Several factors effect the rate at which the crystallizing machine can process preforms, including polyester resin properties, oven efficiency, temperature the preform attains in the oven, and time spent in the oven. Accordingly, increasing efficiency by minimizing the amount of time and additional energy required to complete the container-forming process having a crystallization step is still needed.
  • the method of the present invention uses a polymer/reheat rate-increasing additive composition to increase the rate of the polymer crystallization and, thus, the efficiency of a conventional container- forming process.
  • this invention in one aspect, relates to a method of producing a thermoplastic polymer preform having at least a crystalline finish portion comprising (i) providing a thermoplastic polymer composition comprising a thermoplastic polymer and at least one reheat rate-increasing additive; (ii) forming a preform from the thermoplastic polymer composition, wherein the preform comprises a finish portion and a body portion; and (iii) exposing at least the finish portion of the preform to energy until crystallized.
  • the present invention relates to a method of producing a thermoplastic polymer container having at least a crystalline finish portion, the method comprising (i) providing a thermoplastic polymer composition comprising a thermoplastic polymer and at least one reheat rate-increasing additive; (ii) forming a preform from the thermoplastic polymer composition, wherein the preform comprises a finish portion and a body portion; (iii) exposing at least the finish portion of the preform to energy until crystallized; and (iv) blow molding the preform into a container, wherein the container has at least a crystalline finish portion.
  • the present invention relates to a method of crystallizing at least a finish portion of a thermoplastic polymer container comprising (i) providing a thermoplastic polymer container comprising a thermoplastic polymer and at least one reheat rate-increasing additive, wherein the container has a finish portion and a body portion; and (ii) exposing at least the finish portion of the container to energy until crystallized.
  • the present invention relates to a method of crystallizing a thermoplastic polymer composition
  • a method of crystallizing a thermoplastic polymer composition comprising (i) providing a thermoplastic polymer composition comprising a thermoplastic polymer and at least one reheat rate-increasing additive; and (ii) exposing at least a portion of the composition to energy until crystallized.
  • the present invention relates to a method for forming containers comprising a heat-set finish on a portion of the container comprising (i) molding a container from a polymer comprising at least one reheat rate-improving additive; and (ii) heat-setting at least a portion of the finish of the container.
  • the present invention relates to a container formed from a thermoplastic polymer comprising a body and a finish, wherein the finish is crystalline and contains a reheat rate-increasing additive.
  • the present invention relates to products made by the processes of the present invention.
  • Figure 1 is a plot of crystallinity (weight percent) of six PET polymers versus radiant energy exposure (watts) of the polymers over a 32.2 second period.
  • the polymers having the reheat rate-increasing additive therein have the highest crystallinity.
  • Figure 2 is a plot of crystallinity (weight percent) of six PET polymers versus production rate (parts/minute) of the polymers. Two of the polymers having the reheat rate-increasing additive therein show higher crystallinity at the same lower production rate indicating a faster crystallization rate for those polymers having the additive.
  • thermoplastic preform a thermoplastic "preform,” “article,” “container” or “bottle” is intended to include the processing of a plurality of thermoplastic preforms, articles, containers or bottles.
  • Ranges may be expressed herein as from “about” or “approximately” one particular value and/or to “abouf'or “approximately” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about,” it will be understood that the particular value forms another embodiment.
  • the rate and percent of crystallization of an amorphous thermoplastic polymer can be increased by incorporating into the polymer a reheat rate-increasing additive before processing by a crystallization machine "Amorphous," for purposes of further defining the polymers of the present invention pnor to crystallization, shall mean substantially noncrystalhne
  • a substantially noncrystalhne polymer typically may have less than about 5 to 7 weight percent crystallinity
  • significant increases in the efficiency of processing heat-set PET container preforms having a crystallized finish portion using the Yoshino process may be obtained by means of the method descnbed herein
  • the process aspects of the invention may be defined as a method of producing molded articles compnsing prepanng a preform of thermoplastic polymer admixed with a reheat rate-mcreasmg additive, subjecting the preform to radiant energy for a penod of time necessary to raise its temperature to above the glass transition temperature of the polymer, and subsequently forming the preform into a desired shape
  • glass transition temperature is defined generally as the temperature at which the polymer changes from a glass-like matenal to a rubbery or leathery matenal
  • the present invention is highly useful because 1 ) the method increases the amount of reheat energy which is absorbed by the preforms, and 2) the method increases (nucleates) the spherulitic crystalline growth rate dunng the step of preform/container crystallization Spherulitic crystalline growth may be defined as the increase in spheroid crystalline bodies m the amorphous polymer
  • the method of the present invention provides preforms/containers having a higher or increased degree of crystallinity m a shorter processing time
  • the method of the present invention further provides a container- forming and/or container-processing step having increased output rates.
  • the present invention comprises a method of producing a thermoplastic polymer preform having at least a crystalline finish portion.
  • the method comprises (i) providing a thermoplastic polymer composition comprising a thermoplastic polymer and at least one reheat rate-increasing additive; (ii) forming a preform from the thermoplastic polymer composition, wherein the preform comprises a finish portion and a body portion; and (iii) exposing at least the finish portion of the preform to energy until crystallized.
  • the invention also relates to a preform produced by the method of this embodiment.
  • the present invention relates to a method of producing a thermoplastic polymer container having at least a crystalline finish portion.
  • This method comprises (i) providing a thermoplastic polymer composition comprising a thermoplastic polymer and at least one reheat rate-increasing additive; (ii) forming a preform from the thermoplastic polymer composition, wherein the preform comprises a finish portion and a body portion; (iii) exposing at least the finish portion of the preform to energy until crystallized; and (iv) blow molding the preform into a container, wherein the container has at least a crystalline finish portion.
  • the preform in step (iv) is at a temperature of from 80 °C to 125 °C for blow molding.
  • the invention also relates to a container produced by the method of this second embodiment.
  • the present invention relates to a method of crystallizing at least a finish portion of a thermoplastic polymer container comprising (i) providing a thermoplastic polymer container comprising a thermoplastic polymer and at least one reheat rate-increasing additive, wherein the container has a finish portion and a body portion; and (ii) exposing at least the finish portion of the container to energy until crystallized.
  • This embodiment differs from that of exposing a preform to energy until crystallized. In this embodiment, at least the fimsh portion of a container, not a preform, is exposed to crystallizing energy
  • the present invention relates to a method of crystallizing a thermoplastic polymer composition
  • the method compnses (l) providing a thermoplastic polymer composition compnsing a thermoplastic polymer and at least one reheat rate-increasing additive, and (n) exposing at least a portion of the composition to energy until crystallized
  • This embodiment is different in that at least a portion of a composition having an additive is exposed to crystallizing energy and not a finish of a preform or a container
  • the thermoplastic polymer composition is in the form of an article, more preferably a container, and even more preferably a bottle
  • the invention relates to a bottle crystallized by the method of this embodiment
  • this invention relates to a method for forming containers compnsing a heat-set finish on a portion of the container compnsing (I) molding a container from a polymer compnsing at least one reheat rate-improving additive, and (n) heat-setting at least a portion of the finish of the container
  • the reheat rate-improving additive is carbon black, iron oxide or antimony metal
  • the polymer compnses antimony metal m a concentration of about 20 ppm (ppm parts per million by weight) or more, iron oxide in a concentration of less than about 12 ppm or carbon black m a concentration of less than about 10 ppm
  • the invention also relates to a container formed from the method of this embodiment
  • the present invention relates to a container formed from a thermoplastic polymer
  • the container compnses a body and a finish, wherein the finish is crystalline and contains a reheat rate-increasing additive
  • the fimsh is at least 25 weight percent crystalline
  • the thermoplastic polymer used for forming the container is poly(ethylene terephthalate) or a copolymer thereof
  • the reheat rate-increasing additive preferably includes, but is not limited to, carbon black, iron oxide, antimony, tin, copper, silver, gold, palladium, platinum or a mixture thereof.
  • the thermoplastic polymer composition is preferably transparent.
  • the thermoplastic polymer may comprise a homopolymer or comprise a copolymer.
  • the polymer is a polyester, and more preferably poly(ethylene terephthalate) or a copolymer thereof.
  • Exposure to energy to crystallize at least the finish portion of the preform or container having the additive is effected for about 25 seconds.
  • the finish of the preform is at least 20 weight percent crystalline after exposure to crystallizing energy.
  • the crystallizing radiant energy is at least partially within the infrared region of the energy spectrum. Further, at least a portion of the preform crystallizes at a rate faster than that of a preform without a reheat rate-increasing additive.
  • the thermoplastic polymer used in the invention is most usually a polyester, particularly a partially aromatic polyester, especially a polyester derived, at least mainly, from an aromatic diacid and an aliphatic (including cycloaliphatic) diol.
  • a prefened partially aromatic polyester is one which comprises at least 50 mole %, preferably at least 70 mole %, of ethylene terephthalate residues.
  • the polyester may also contain residues derived from ethylene isophthalate, ethylene naphthalate, ethoxyethylene terephthalate, ethoxyethylene isophthalate or ethoxyethylene naphthalate.
  • polyesters such as polyethylene terephthalate polymer (PET) are made by reacting a glycol with a dicarboxylic acid as the free acid or its dimethyl ester to produce a prepolymer compound which is then polycondensed to produce the polyester. If required, the molecular weight of the polyester can then be increased further by solid state polymerization.
  • PET polyethylene terephthalate polymer
  • Suitable polyesters for the method of the present invention include crystallizable polyester homopolymers or copolymers that are suitable for use in containers and packaging, and particularly food packaging.
  • the present invention provides accelerated crystallization rates for any thermoplastic resins, e.g., PET containing a reheat rate-increasing additive.
  • Suitable polyesters are generally known in the art and may be formed from aromatic dicarboxyhc acids, esters of dicarboxyhc acids, anhydrides of dicarboxyhc esters, glycols, and mixtures thereof.
  • the polyesters are formed from repeat units comprising terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, dimethyl-2,6- naphthalenedicarboxylate, 2,6-naphthalenedicarboxylic acid, ethylene glycol, diethylene glycol, 1,4-cyclohexane-dimethanol, 1,4-butanediol, and mixtures thereof.
  • the dicarboxyhc acid component of the polyester may optionally be modified with one or more different dicarboxyhc acids.
  • additional dicarboxyhc acids include aromatic dicarboxyhc acids preferably having 8 to 14 carbon atoms, aliphatic dicarboxyhc acids preferably having 4 to 12 carbon atoms, or cycloaliphatic dicarboxyhc acids preferably having 8 to 12 carbon atoms.
  • dicarboxyhc acids to be included with terephthalic acid are: phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexanediacetic acid, diphenyl-4,4'-dicarboxylic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, mixtures thereof and the like.
  • the amount of said second dicarboxyhc acid is less than 30 mole% and more preferably less than about 15 mole%.
  • glycol component may optionally be modified with one or more different glycols other than ethylene glycol.
  • additional glycols include cycloaliphatic diols preferably having 6 to 20 carbon atoms or aliphatic diols preferably having 3 to 20 carbon atoms.
  • glycols examples include: diethylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol, propane- 1,3-diol, butane- 1,4-diol, pentane-l,5-diol, hexane-l,6-diol, 3-methylpentanediol-(2,4), 2- methylpentanediol-( 1 ,4), 2,2,4-trimethylpentane-diol-(l ,3), 2-ethylhexanediol-(l ,3), 2,2-diethylpropane-diol-( 1 ,3), hexanediol-(l ,3), 1 ,4-di-(hydroxyethoxy)-benzene, 2,2-bis-(4-hydroxycyclohexyl)-propane, 2,4-dihydroxy-l,l,3,3-tetramethyl- cyclo
  • the thermoplastic resin may also contain small amounts of trifunctional or tetrafunctional comonomers such as trimellitic anhydride, trimethylolpropane, pyromellitic dianhydride, pentaerythritol, and other polyester forming polyacids or polyols generally known in the art.
  • trifunctional or tetrafunctional comonomers such as trimellitic anhydride, trimethylolpropane, pyromellitic dianhydride, pentaerythritol, and other polyester forming polyacids or polyols generally known in the art.
  • the thermoplastic polymers according to this invention include at least one reheat rate-increasing additive.
  • Reheat rate is defined as the change in average temperature of a molded part as a function of exposure to a radiant heat source for a specified time.
  • Suitable reheat rate-increasing additives are well known in the art and include, preferably, black and gray body absorbers such as carbon black, antimony metal, iron oxide and the like, as well as near infrared absorbing dyes, including, but not limited to those disclosed in U.S. 97/15351, which is incorporated herein by reference.
  • the reheat rate-increasing additive should be present in an amount sufficient to improve the reheat rate of an unmodified polymer.
  • the actual amount of reheat rate-increasing additive will vary depending on which additive is used.
  • the thermoplastic polymer composition comprises the reheat rate-increasing additive in a concentration of about 1 to 300 ppm.
  • the reheat rate-increasing additive may be typically any reheat rate-increasing additive used in the art, including, but not limited to, carbon black, iron oxide, antimony, tin, copper, silver, gold, palladium, platinum or a mixture thereof.
  • the polymer composition may comprise antimony metal in a concentration of at least 10 ppm.
  • the more effective concentration of the iron oxide is from about 1.0 to about 100 ppm, preferably from about 1 to about 50 ppm with 1-30 ppm being most preferred.
  • the iron oxide, preferably Fe 2 0 3 is used in very finely divided form e.g., from about 0.01 to about 200 ⁇ m, preferably from about 0.1 to about 10.0 ⁇ m, and most preferably from about 0.2 to about 5.0 ⁇ m.
  • Such oxides are described, for example, on pages 323-349 of Pigment Handbook, Vol. 1, copyright 1973, John Wiley & Sons, Inc.
  • Iron oxide for example, can be added to the polyester reactant system, during or after polymerization, to the polyester melt, or to the molding powder or pellets from which the bottle preforms are formed.
  • the bottle preforms are test tube shaped, injection moldings which are heated above the glass transition temperature of the polymer and then positioned in the bottle mold to receive the pressurized air through its open end.
  • Any radiant energy source may be employed, and the one used for heating the preforms according to this invention is a quartz lamp, Model Q-1P, 650 W., 120 V., by Smith Victor Corp.
  • Suitable preferred metals for use as the additive according to the method of this invention include antimony, tin, copper, silver, gold, palladium and platinum or a mixture of two or more of these. It should also be appreciated that additional gray and black body absorbers including, but not limited to arsenic, cadmium, mercury and lead can also be used. However, for most applications, silver, gold, arsenic, cadmium, mercury, lead, palladium and platinum are either too expensive or environmentally hazardous and these metals are, consequently, not particularly preferred.
  • the metal is one or more of antimony, tin or copper with antimony being particularly advantageous.
  • the metal if metal is used as the reheat rate-increasing additive, the metal preferably is in particle form for ease of processing.
  • the metal particles are preferably sufficiently fine for them not to be visible to the eye and have a range of sizes such that abso ⁇ tion of radiation occurs over a relatively wide part of the wavelength range and not just at one particular wavelength or over a narrow band.
  • the amount of metal particles present in the thermoplastic polymer composition is a balance between the desired reduction in the reheat time of the polymer, the crystallization of the polymer and the amount of haze that is acceptable for a given application.
  • the amount of metal particles is from about 1 ppm to 300 ppm, more particularly from about 5 ppm to 150 ppm, and especially from about 10 ppm to 100 ppm. If desired, masterbatches of the polymer composition containing quantities of metal particles in far higher concentrations can be made for subsequent blending with polymer essentially free from the metal particles to achieve the desired levels of particles.
  • antimony is especially preferred because, in the form of antimony trioxide (antimony (III) oxide), it is a catalyst for the polymerization of the monomers used in the preparation of polyesters such as poly( ethylene terephthalate).
  • antimony metal present in the polyester melt is a slightly reducing environment, the polyesters may naturally have a very minor proportion of antimony metal present, e.g., upt o about 5-6 ppm. However, these low levels of antimony metal do not affect the reheat time significantly.
  • additives and/or lubricants normally used in polyesters may be used if desired.
  • additives include catalysts, colorants, pigments, glass fibers, fillers, impact modifiers, antioxidants, stabilizers, processing aids, flame retardants, acetaldehyde reducing compounds and the like.
  • the method of the present invention is particularly suited for use in the production of a heat-set thermoplastic polymer (e.g., polyester) container.
  • a polyester preform for example, is molded in the injection molding machine from a polyester resin containing a reheat rate-increasing additive.
  • the preform is molded according to known techniques, whereby polyester pellets are dried and injection molded to produce clear, amorphous polyester preforms.
  • the amorphous or "glassy" preforms preferably comprise a threaded finish portion and a body portion.
  • the finish portion is crystallized according to the present invention to prevent distortion of the finish upon further processing of the preform to produce a container, or upon heat-filling of the container.
  • the body portion of the preform is typically processed, as by heated blow molding, to form a container having a desired shape and size.
  • a portion of the preform is crystallized.
  • Preferably, only the finish is crystallized.
  • Crystallization of the finish is usually an optional, and, until now, predominantly cumbersome stage of a preform-forming process.
  • crystallization rates are dramatically increased rendering a crystallization stage more desirable in many container-forming applications.
  • crystallization involves exposing at least a portion of the preform finish to radiant heat from lamps in a row of ovens (across a spectrum which may include the IR range) while protecting the body of the preform.
  • the preform is transported to a crystallization machine.
  • the preforms are preferably loaded into carriers which shield the bodies of the preforms against exposure to crystallizing heat, but leave the finishes exposed.
  • the carriers, containing the preforms are passed through the crystallizing machine, where the preform finishes are exposed to infrared energy for a sufficient amount of time to allow the finishes to crystallize.
  • This stage preferably involves exposing at least a portion of the preform finish to radiant heat from lamps in a row of ovens (across a spectrum that may include the IR range) while protecting the body of the preform.
  • the finish is heated to temperatures at which the selected polyester crystallizes rapidly (for PET about 150°C to about 180°C).
  • spherulitic crystallinity levels at a minimum of about 20 weight percent.
  • These high levels of crystallinity give dimensional stability to the finish that enable the resulting container to be hot-filled without suffering from thermal distortion in the finish region.
  • at least a portion of the preform crystallizes at a rate faster than that of a preform without a reheat rate-increasing additive.
  • Crystallization of the finish can be performed either to the preform (as in the Yoshino process), to a pre-bottle (as in the Sidel SRCF process outlined in U.S. Patent No. 5,382,157), or to the actual heat-set bottle.
  • the desired container is preferably blow molded from the preform and heat- set, according to known techniques.
  • the preform body (with or without the crystallized finish) is exposed lamps emitting radiant heat (which may include the IR range of the spectrum) until the preform has reached the appropriate temperature range for bottle blowing (from about 85°C to about 120°C for PET).
  • the preform is removed from the oven and placed into a warm or hot blow mold and pressurized.
  • the preform is thereby stretched into a container, preferably a bottle which is held against the warm or hot blow mold (therefore, the name "heat-set").
  • a container preferably a bottle which is held against the warm or hot blow mold (therefore, the name "heat-set”).
  • These bottles are typically designed to withstand hot-filling without shrinkage greater than about 1% by volume. It is also desirable, although not required, to achieve a large degree of spherulitic crystallinity in the bottle sidewall in order to resist thermal distortion upon hot-filling of the bottle.
  • Crystallization of the bottle preforms occurs through crystal nucleation.
  • Crystal nucleation in the preform is primarily heterogeneous. That is, the initial seed crystal forms at the surface of a pre-existing foreign particle in the resin, in the present case, a reheat rate-increasing additive.
  • the additive in accordance with the present invention, is a component intentionally added to promote increased reheat rates and nucleation.
  • the density of crystal nucleation is controlled by the density of the additive as well as the rate at which seed crystals of polymer form at the surface of the additive, which is in turn influenced by material variables and temperature.
  • a polymer preform was injection molded. Specfically, preblended polymer
  • PET Homopolymer or modified PET pellet concentration @ 50:1 let down ratio resulting in a 12 ppm level of black iron oxide was formed.
  • Preforms were molded from the blend on a standard injection molding machine (4-cavity Husky LX-160). This injection molding machine is well known to one of ordinary skill in the art and, as such, need not be described in detail here.
  • preforms were crystallized on standard reheat equipment (Sidel SBO 2/3), which typically can be a stretch blow molding machine. This equipment is well known to one of ordinary skill in the art and, as such, need not be described in detail here.
  • standard reheat equipment Sidel SBO 2/3
  • This equipment is well known to one of ordinary skill in the art and, as such, need not be described in detail here.
  • preforms were subjected to the following various heating times and/or energy exposure levels to a point at which crystallization of the preform body occurred:
  • the crystallinity of the preforms was determined by first measuring gradient tube density, then converting density to weight percent crystallinity using the equations standard to the industry. Both measuring gradient tube density and converting density to crystallinity using standard equations are known to one of ordinary skill in the art and, as such, need not be described in detail here. The results of the examples tested are illustrated in Figures 1 and 2.
  • a PET Homopolymer preform with approximately 12 ppm black iron oxide was prepared by the method outlined above and subjected to approximately 475,000 watts of exposure of IR over a 32.2 second period.
  • the preform developed 41 weight percent crystallinity.
  • the same PET Homopolymer preform was prepared without the black iron oxide and subjected to the same exposure conditions. This preform developed only 10 weight percent crystallinity.
  • Figure 1 is a plot of experimental results demonstrating the crystallinity (weight percent) of various forms of PET after exposure to radiant energy (watts) over the 32.2 second reheat period.
  • Figure 2 is a plot of experimental results demonstrating the crystallinity (weight percent) of the
  • FIGs 1 and 2 refer to the following forms of PET manufactured and used by
  • EASTAPAK (R) copolyester B-l 1) with and without a reheat rate-increasing additive.
  • three forms of PET contain a reheat rate-increasing additive in accordance with the method of this invention: PET Homopolymer; CHDM Modified PET; and IPA Modified PET.
  • Figure 1 illustrates that at the end of the reheat period (32.2 seconds), wherein the PET forms are exposed to a final radiant energy of approximately 450,000 watts, the three above-mentioned PET forms having the reheat additive clearly have a higher crystallinity than those without the reheat additive.
  • PET polymers having the reheat rate-increasing additive is markedly increased over those PET polymers without the additive. For example, at lower production rates (8- 10 parts/minute), the 0.8 PET Homopolymer and 0.8 ItV CHDM modified PET having the reheat additive show over double (at 8 parts/minute) the crystallinity of those PET polymers without the additive. These results strongly suggest that 1) the rate of crystallization of the PET polymers with the additive is significantly higher than those without the additive, and 2) the reheat rate-increasing additive is the reason for the dramatic increase is the rate of crystallization. First, the PET polymers are the same (i.e., 0.8 ItV and modified with the same copolymers).
  • the processing conditions are the same (i.e., temperature, time, rate, exposure to energy). Therefore, the only experimental variable that distinguishes the results shown in Figure 2 is the reheat rate-increasing additive, and the results show that the additive dramatically improves crystallization of the PET polymers.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
  • Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

Procédé de production d'une préforme de polymère thermoplastique ayant au moins une partie goulot cristalline, qui consiste (1) à obtenir une composition polymère thermoplastique comprenant un polymère thermoplastique et au moins un additif d'augmentation de la vitesse de rechauffe, (2) à former une préforme à partir de la composition polymère thermoplastique, la préforme comprenant une partie goulot et une partie corps, et (3) à exposer au moins la partie goulot de la préforme à de l'énergie jusqu'à ce que ladite partie cristallise.
PCT/US1999/011659 1998-05-27 1999-05-27 Procede de production d'une preforme de polymere thermoplastique et article ainsi produit WO1999061514A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
CA002332984A CA2332984A1 (fr) 1998-05-27 1999-05-27 Procede de production d'une preforme de polymere thermoplastique et article ainsi produit
BR9910709-0A BR9910709A (pt) 1998-05-27 1999-05-27 Processo para produzir uma pré-forma de polìmero termoplástico, pré-forma, processo para cristalizar pelo menos uma porção do acabamento de um recipiente de polìmero termoplástico, recipiente, processos para produzir um recipiente de polìmero termoplástico e para cristalizar uma composição de polìmero termoplástico, garrafa, e, processo para formar um recipiente compreendendo um acabamento ajustado por calor em uma porção do recipiente
EP99925890A EP1082377A1 (fr) 1998-05-27 1999-05-27 Procede de production d'une preforme de polymere thermoplastique et article ainsi produit
JP2000550911A JP2002516204A (ja) 1998-05-27 1999-05-27 熱可塑性ポリマープレフォームの製造方法及びそれから製造される物品

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US8692498P 1998-05-27 1998-05-27
US60/086,924 1998-05-27

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WO1999061514A1 true WO1999061514A1 (fr) 1999-12-02

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001083193A1 (fr) * 2000-04-28 2001-11-08 Advanced Plastics Technologies, Ltd. Bouteilles et preformes a goulot cristallin
EP1535944A1 (fr) * 2003-11-28 2005-06-01 Futura Polymers Procédé de préparation d'une résine polyéthylènetéréphtalate avec des propriétés de rechauffe rapides pouvant être utilisée dans la fabrication de bouteilles

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7358322B2 (en) * 2004-03-09 2008-04-15 Eastman Chemical Company High IV melt phase polyester polymer catalyzed with antimony containing compounds
GB0407114D0 (en) * 2004-03-30 2004-05-05 Colormatrix Europe Ltd Polymer additives and methods of use thereof
US7816436B2 (en) * 2004-11-08 2010-10-19 INVISTA North America S.à.r.l. Carbon black with large primary particle size as reheat additive for polyester and polypropylene resins
CN111773762B (zh) * 2020-06-09 2022-03-08 江苏恒科新材料有限公司 一种节能紧凑型聚酯切片结晶干燥系统
WO2023100897A1 (fr) * 2021-11-30 2023-06-08 三菱エンジニアリングプラスチックス株式会社 Composition de résine, article moulé, composite et composite métal/résine

Citations (3)

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Publication number Priority date Publication date Assignee Title
US4535118A (en) * 1982-02-24 1985-08-13 The Goodyear Tire & Rubber Company High clarity, low haze polyesters having reduced infrared heat-up times
WO1994010242A1 (fr) * 1992-10-26 1994-05-11 Allied-Signal Inc. Systeme de nucleation pour des polyesters et articles formes a partir de ces derniers
US5419936A (en) * 1989-11-24 1995-05-30 Ici Chemical Industries Plc Polyester bottles

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4535118A (en) * 1982-02-24 1985-08-13 The Goodyear Tire & Rubber Company High clarity, low haze polyesters having reduced infrared heat-up times
US5419936A (en) * 1989-11-24 1995-05-30 Ici Chemical Industries Plc Polyester bottles
WO1994010242A1 (fr) * 1992-10-26 1994-05-11 Allied-Signal Inc. Systeme de nucleation pour des polyesters et articles formes a partir de ces derniers

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001083193A1 (fr) * 2000-04-28 2001-11-08 Advanced Plastics Technologies, Ltd. Bouteilles et preformes a goulot cristallin
EP1535944A1 (fr) * 2003-11-28 2005-06-01 Futura Polymers Procédé de préparation d'une résine polyéthylènetéréphtalate avec des propriétés de rechauffe rapides pouvant être utilisée dans la fabrication de bouteilles

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CA2332984A1 (fr) 1999-12-02
CN1311807A (zh) 2001-09-05
BR9910709A (pt) 2001-01-30
AR018393A1 (es) 2001-11-14
JP2002516204A (ja) 2002-06-04
EP1082377A1 (fr) 2001-03-14

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