Title of Invention

A POLYMER COMPOSITION

Abstract A polymer composition and method for reducing the permeability of gases through molded polymeric containers and films by incorporating into the polymer from which the container or film is formed effective amount of a barrier-enhancing additive, such as monoesters of hydroxybenzoic acid hydroxynapthoic acid.
Full Text FORM 2
THE PATENTS ACT, 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See Section 10; rule 13]
"A POLYMER COMPOSITION"
E.I.DU PONT DE NEMOURS AND COMPANY, a Delaware corporation, of 1007 Market Street, Wilmington, Delaware 19898, United States of America,
The following specification particularly describes the nature of the invention and the manner in which it is to be performed:-


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TITLE
METHOD AND COMPOSITION FOR IMPROVING GAS BARRIER PROPERTIES OF POLYMERIC CONTAINERS AND FILMS
CROSS REFERENCED) TO RELATED APPLICATIONS
This application claims priority benefit from U.S. provisional patent application no. 60/148,537 filed August 12, 1999.
BACKGROUND OF THE INVENTION
The present invention is a polymer composition and method for improving the gas barrier performance of polymeric containers and films, and particularly containers for food and beverages which are molded from thermoplastic polyester polymers. More particularly, the invention is a polymer composition and method for reducing the permeability of gases through molded polymeric containers, sheets and films by incorporating into the polymer from which the container, sheet or film is formed an effective amount of a barrier-enhancing additive of the type described herein.
The addition of small amounts of molecular additives to a base polymer can result in antiplasticization of the polymer whereby the modulus of the polymer increases below its glass transition temperature and its barrier to gas permeability can improve. For example, Robeson describes the use of phenyl-2-naphthyl amine in polysulfone [Robeson, L.M; Faucher, J.A., J. Polym. Sci, Part B 7, 35-40 (1969)] and various polychlorinated aromatic molecules in polycarbonate and in polyvinyl chloride [Robeson, L.M., Polym. Eng. Sci. 9, 277-81 (1969)]. Maeda and Paul [Maeda, Y.; Paul, D.R., J. Polym. Set, Part B: Polym. Phys. 25, 981-1003 (1987)] disclose the use of tncresyl phosphate in polyphenylene oxide to lower the sorption of carbon dioxide (and therefore its permeability). However, the need exists to improve the gas barrier performance of polymer resins of the type currently used for molded containers for food and beverages, and, in particular, poly (ethylene) terephthalate (PET) thermoplastic polyester polymers used for producing injection stretch blow molded bottles for packaging water, carbonated soft drinks and beer. Additives selected from 4-hydroxybenzoates and related molecules of the type described herein have not been suggested.
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SUMMARY OF THE INVENTION
The present invention and the inventive features described herein reside in the discovery of certain barrier-enhancing additives for thermoplastic polymers. The invention is a polymer composition that contains one or more of the additives and a method for reducing gas permeability of shaped polymeric articles produced from such a composition, such articles being generally selected from containers, sheets and films.
The method comprises incorporating into the polymer an effective amount of a barrier-enhancing additive, or a mixture of barrier-enhancing additives, selected from the group consisting of:
(a) monoesters of hydroxybenzoic acid and hydroxynaphthoic acid of the formula (A)






15

wherein R is C] - Cg aikyl, benzyl, phenyl or naphthyx; Ar is substituted or unsubstituted phenylene or naphthalene; or formula (AA) where M is a cation such as, but not limited to, sodium, ammonium, tetraalkyl ammonium, potassium, calcium, magnesium or zinc;
(b) diesters of hydroxybenzoic acid of the formula (B)


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wherein Ar is as defined above, and R1 is C1 - Cg alkyl, (CH2CH20)kCH2CH2 where k is 1 or more, benzyl, phenyl or naphthyl; or formula (BB) where M is as defined above.
(c) monoamides of hydroxybenzoic acid and hydroxynaphthoic acid of the formula (C)

wherein R and Ar are as defined above; or formula (CC) where M is as defined above.
(d) diamides of hydroxybenzoic acid of the formula (D)

wherein Ar is as defined above, and R2 is C] - Cg alkyl, (CH2CH20)kCH2CH2 where k is 1 or more, benzyl, phenyl or naphthyl; or formula (E>D) where M is as defined above.
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(e) ester-amides of hydroxybenzoic acid of the formula (E)
where Ar is as defined above and R3 is C\ - Cg alkyl, C\ - Cg dialkyl, (CH2CH20)kCH2CH2 where k is 1 or greater, benzyl, phenyl or naphthyl, or 5 formula (EE) where M is as defined above. As used herein, an effective amount, i.e., the preferred range of barrier enhancing additive, is from 0.1% by wt. to 20% by wt. of the base polymer comprising the polymeric article.
Polymeric articles, and particularly extruded film or injection stretch blow molded polyester (e.g., PET) bottles, which contain one or more of the 1 barrier-enhancing additives described herein, exhibit substantially reduced oxygen and carbon dioxide permeability values when measured according to ASTM D3985 and water vapor permeability values when measured according to ASTM F1249 in comparison to corresponding polymeric articles which contained no barrier-enhancing additives.
DETAILED DESCRIPTION OF THE INVENTION The present invention resides in the discovery that oxygen, water vapor and carbon dioxide (C02) permeability values for shaped polymeric containers and films can be substantially reduced by incorporating into the base polymer from which the articles are formed from about 0.1% by wt. up to about 20% by wt. of a 20 barrier-enhancing additive of the type defined herein.
A uniform physical blend, or mixture, is prepared comprising the base polymer and one or more barrier-enhancing additives in the desired concentrations. As used herein with reference to the invention, the term "composition" is intended to mean a physical blend or mixture. Water-sensitive base polymers, such as, for


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example, polyesters should preferably be thoroughly dried by heating under air or
nitrogen flow or vacuum as known to those experienced in the art. The mixture is
then heated and extruded or molded at a sufficiently high temperature to melt the base
polymer and provide for sufficient mixing of the additive or mixture of additives
within the base polymer matrix. By way of example using PET/such melt
temperature ranges from about 255°C to 300°C. The composition thus produced
comprises the barrier-enhancing additive (or mixture of such additives) substantially
in its (their) original molecular form; that is, only small amounts of barrier-enhancing
additive have been observed to react with the base polymer via trans-esterification or
10 other reaction mechanism typical of the functional groups present. It is preferred to
prepare and extrude or mold the polymer composition under conditions of relatively
low temperature and processing residence time which thereby minimizes the
opportunity for the barrier-enhancing additives to react with the base polymer. Best
performance in terms of desirable mechanical properties of polymeric containers and
films produced according to the invention is achieved when no more than about 10%
of the gas barrier-enhancing additive has reacted with the base polymer. As a
consequence of any reaction of a gas barrier-enhancing additive within the scope of
the invention with a base polymer, the molecular weight of the starting base polymer
may decrease.
2(|) The gas barrier-enhancing additives found to be most suitable for carrying out
the invention are selected from the group consisting of:
(a) monoesters of hydroxybenzoic acid and hydroxynaphthoic acid of the formula (A)


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wherein R is C1 - Cg aikyl, benzyl, phenyl or naphthyl; Ar is substituted or
unsubstituted phenylene or naphthylene; or formula (AA) where M is a cation such as,
but not limited to, sodium, ammonium, tetraalkyl ammonium, potassium, calcium,
magnesium or zinc;
5 (b) diesters of hydroxybenzoic acid of the formula (B)

wherein Ar is as defined above, and R1 is C1- C8 alkyl, (CH2CH20)kCH2CH2 where k is 1 or more, benzyl, phenyl or naphthyl; or formula (BB) where M is as 1() defined above.
(c) monoamides of hydroxybenzoic acid and bydroxynaphthoic acid of the formula (C)

15 wherein R and Ar are as defined above; or formula (CC) where M is as defined above.
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(d) diamides of hydroxybenzoic acid of the formula (D)

wherein Ar is as defined above, and R2 is C1 - Cg alkyl, (CH2CH20)kCH2CH2 where k is 1 or more, benzyl, phenyl or naphthyl; or formula (DD) where M is as defined above.
(e) ester-amides of hydroxy benzoic acid of the formula (E)

where Ar is as defined above and R3 is Cj - Cg alkyl, Cj - Cg dialkyl,
(CH2CH20)kCH2CH2 where k is 1 or greater, benzyl, phenyl or naphthyl, or
formula (EE) where M is as defined above.
The above-defined barrier-enhancing additives can be obtained from
commercial suppliers or they can be synthesized using established procedures.
Base polymers most suitable for use in practicing the invention comprise thermoplastic homopolymers, copolymers (both block and random), and blends of such thermoplastic polymers. Most suitable are polyester homopolymers and copolymers. Among suitable polyester base polymers are those polymers which contain structural units derived from one or more organic diacids (or their corresponding esters) selected from the group consisting of terephthalic acid,
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isophthalic acid, naphthalene dicarboxylic acids, hydroxybenzoic acids,
hydroxynaphthoic acids, cyclohexane dicarboxylic acids, succinic acid, glutaric acid,
adipic acid, sebacic acid, 1,12-dodecane dioic acid and the derivatives thereof, such
as, for example, the dimethyl, diethyl, or dipropyl esters or acid chlorides of the
dicarboxylic acids and one or more diols selected from ethylene glycol, 1,3-propane
diol, nathphalene glycol, 1,2-propanediol, 1,2-, 1,3-, and 1,4-cyclohexane dimethanol,
diethylene glycol, hydroquinone, 1,3-butane diol, 1,5-pentane diol, 1,6-hexane diol,
triethylene glycol, resorcinol, and longer chain diols and polyols which are the
reaction products of diols or polyols with alkylene oxides.
1 0 In a preferred embodiment of the invention the polyester base polymer is
polyethylene terephthalate (PET), which includes PET polymer which has been modified with from about 2 moIe% up to about 5 mole% of isophthalate units. Such modified PET is known as "bottle grade" resin and is available commercially as Melinar® Lasert- polyethylene terephthalate brand resin (E. I. du Pont de Nemours and Company, Wilmington, DE). As used hereinafter in illustrating the invention, the term PET will refer to commercially available "bottle grade" polyester resin.
Preparation of Film and Container Samples
Film samples are indicative of the improved gas barrier properties obtainable from the invention. Such film samples were generated from physical blends of a base polymer and a selected additive from among those described herein, and the samples were either compression molded or extrusion cast using a co-rotating twin screw extruder with a slit die, typically having a 0.38 mm gap, a quench roil, and a vacuum port on the front barrel section, with barrel, adapter, and die temperatures set at 240°C 2|5 to 275°C depending on the polymer composition being used. Melt temperatures were measured with a thermocouple, and, for samples prepared using a twin screw extruder, melt temperatures were typically about 15°C to 20°C above the set temperature. In a few instances as noted, a transfer line, in which static mixers were installed within the line in place of a compounding screw, was used along with a slit die. Films were typically 0.05 to 0.25 mm thick. The thick films were subsequently stretched biaxially simultaneously to 3,5X.hy3.5^C using a Long stretcher at 90°C, 9000%/minute unless otherwise
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For fabricating bottles, 26g preforms were injection molded using a Nissei ASB 50 single stage injection stretch blow molding machine with barrel temperatures set at about 265°C and with a total cycle time of about 30 seconds. The preforms were immediately blown into 500 mL round-bottomed bottles with a blow time of 5 seconds. All other pressure, time and temperature set-points were typical for commercially available PET bottle resin.
Tensile bars 1/8" thick were molded using a 6oz. injection molding machine with the following machine set-up: barrel temp: 255°C, mold temp: 20°C/20°C, cycle time: 20 sec/20 sec, injection pressure: 5.5 MPa, RAM speed: fast, screw speed: lp 60 rpm, and back pressure: 345 kPa,
Analytical Procedures
NMR Spectrometry
1|5 Samples for 1H NMR were dissolved in tetrachloroethane-d2 at 130°C.
Spectra were acquired at 120°C at 500 MHz.
Thermal Analysis
Differential Scanning Calorimetric data were acquired at 2°/min on a TA 2p Instruments calorimeter.
Permeability
Oxygen permeability values (OPV) were measured for each sample according to ASTM procedure D3985 at 30°C, 50% RH on an Ox-Tran 1000 instrument from 25 Modern Controls, Inc. Carbon dioxide permeability was measured at 25°C and 0% RH on a Permatran CIV instrument, also from Modem Controls, Inc. Water vapor permeability was measured at 37-38°C, 100% RH on a Permatran-W600 instrument, also from Modern Controls, according to ASTM procedure F1249.
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Intrinsic-Viscosity
Intrinsic viscosity values were, determined from 0.4 wt% solution of polymers or polymer blends in a 1:1 (by weight) mixture of methylene chloride and trifluoroacetic acid at 20°C.
The present invention relates to" a polymer composition comprising (1) a base which is selected from thermoplastic homopolymers, random or block copolymers and a blend or blends of such homopolymers and copolymers and (2) a concentration of from 0.1% by wt. upto 20% by wt. of the composition of a gas barrier-enhancing molecular addictive or mixture of such gas barrier-enhancing molecular additives selected from the group consisting of:
a)monoesters of hydroxybenzoic acid and hydroxynaphthoic acid of the formula (A)

wherein R is C1 - C8 alkyl, benzyl, phenyl or naphthyl; Ar is substituted or unsubstituted phenylene or naphthylene; or formula (AA) where M is a cation such as, but not limited to, sodium, ammonium, tetraalkyl ammonium, potassium, calcium, magnesium or zinc;


(b) diesters of hydroxybenzoic acid of the formula (B)

wherein Ar is as defined above, and R1 is C1-C4 alkyl, (CH2CH20)kCH2CH2 where k is 1 or more, benzyl, phenyl or naphthyl; or formula (BB) where M is as defined above.
(c) monoamides of hydroxybenzoic acid and hydroxynaphthoic acid of the formula (C)

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wherein R and Ar are as defined above; or formula (CC) where M is as defined above, (d) diamides of hydroxybenzoic acid of the formula (D)


wherein Ar is as defined above, and R2 is C1 -Cs alkyl, (CH2CH20)kCH2CH2 where k is 1 or more, benzyl, phenyl or naphthyl; or formula (DD) where M is as defined above, (e) ester-amides of hydroxybenzoic acid of the formula (E)

where Ar is as defined above and R3 is C1 - C8 alkyl, C1 - C8 dialkyl, (CH2CH20)kCH2CH2 where k is 1 or greater, benzyl, phenyl or naphthyl, or formula (EE) where M is as defined above.
/5
EXAMPLES
Example 1
Films comprising commercially available PET resin (Melinar® Laser+ PET
Vp brand resin) as the base polymer plus a barrier additive were prepared by a variety of
methods as follows: melt pressing (M), extrusion compounding through a slit die (E),
and transfer line mixing (T) into a slit die, and noted below in the table.
Compositions are indicated in Table 1. After extrusion, films were simultaneously
biaxially stretched to 3.5X by 3.5X at 90°C and at a rate of 9000%/min. Oxygen
15 permeation values (OPV) were measured according to ASTM procedure D3985 at 30°
C, 50% relative humidity. Weight percent of the additive in the resin was assayed by
NMR; where such analysis was not possible, nominal values (i.e., amounts initially
mixed into the resin) are noted. In each case, both in unstretched and stretched films,
the OPV was lower in films which contained a barrier-enhancing additive according
20 to the invention than typical PET values (Control values, Table 1). OPV units are
cc-mils/l 00 sq. in-24 hr-atm.
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Intrinsic-Viscosity
Intrinsic viscosity values were, determined trom 0.4 wt% solution of polymers or polymer blends in a 1:1 (by weight) mixture of methylene chloride and trifluoroacetic acid at 20°C.
The present invention relates to"a polymer composition comprising (1) a base which is selected from thermoplastic homopolymers, random or block copolymers and a blend or blends of such homopolymers and copolymers and (2) a concentration of from 0.1% by wt. upto 20% by wt. of the composition of a gas barrier-enhancing molecular addictive or mixture of such gas barrier-enhancing molecular additives selected from the group consisting of:
a)monoesters of hydroxybenzoic acid and hydroxynaphthoic acid of the formula (A)

wherein R is C1 - C8 alkyl, benzyl, phenyl or naphthyl; Ar is substituted or unsubstituted phenylene or naphthylene; or formula (AA) where M is a cation such as, but not limited to, sodium, ammonium, tetraalkyl ammonium, potassium, calcium, magnesium or zinc;
(b) diesters of hydroxybenzoic acid of the formula (Bj



wherein Ar is as defined above, and R1 is C1-C4 alkyl, (CH2CH20)kCH2CH2 where k is 1 or more, benzyl, phenyl or naphthyl; or formula (BB) where M is as denned above.
(c) monoamides of hydroxybenzoic acid and hydroxynaphthoic acid of the formula (C)

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wherein R and Ar are as defined above; or formula (CC) where M is as defined above, (d) diamides of hydroxybenzoic acid of the formula (D)


wherein Ar is as defined above, and R2 is C1 -Cs alkyl, (CH2CH20)kCH2CH2 where k is 1 or more, benzyl, phenyl or naphthyl; or formula (DD) where M is as defined above, (ej ester-amides of hydroxybenzoic acid of the formula (E)

where Ar is as defined above and R3 is Ci - Cs. alkyl, Ci - Cs dialkyl,
(CH2CH20)kCH2CH2 where k is 1 or greater, benzyl, phenyl or naphthyl, or
formula (EE) where M is as defined above. 5
EXAMPLES
Example 1
Films comprising commercially available PET resin (Melinar® Laser+ PET
10 brand resin) as the base polymer plus a barrier additive were prepared by a variety of
methods as follows: melt pressing (M), extrusion compounding through a slit die (E),
and transfer line mixing (T) into a slit die, and noted below in the table.
Compositions are indicated in Table 1. After extrusion, films were simultaneously
biaxially stretched to 3.5X by 3.5X at 90°C and at a rate of 9000%/min. Oxygen
15 permeation values (OPV) were measured according to ASTM procedure D3985 at 30°
C, 50% relative humidity. Weight percent of the additive in the resin was assayed by
NMR; where such analysis was not possible, nominal values (i.e., amounts initially
mixed into the resin) are noted. In each case, both in unstretched and stretched films,
the OPV was lower in films which contained a barrier-enhancing additive according
20 to the invention than typical PET values (Control values, Table 1). OPV units are
cc-mils/100 sq. in-24 hr-atm.
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Table 1

Sample Preparation* Additive Wt% (NMR) OPV: Unstretched OPV: Stretched
Control E None 0 11.08** 7.23**
A M Methyl 4-hydroxybenzoate 2.48 7.07 3.48
B T Methyl 4-hydroxybenzoate 5.74 3.76 3.56
C T Methyl 4-hydroxybenzoate 3.49 7.14 3.69
D T Methyl 4-hydroxybenzoate 1.55 8.17 4.70
E T Methyl 4-hydroxybenzoate 0.66 5.91
F . E Ethyl 4-hydroxybenzoate 3.71 5.42 4.14
G E n-Propyl 4-nyaVoxyienzoate 2.90 7.91 4.74
H E i-Propyl 4-hydroxybenzoate 6.00 (nominal) 4.01
I M Benzyl 4-hydroxybenzoate 5.88 (nominal) 8.87 3.99
J M Phenyl 4-
hydroxybenzoate 5.55 (nominal) 7.71 3.82
K E Phenyl hydroxynaphthoate 5 (nominal) 8.49 4.47
* Preparation methods: E = extrusion compounded then extrusion through a slit die to make film; M = melt-pressed film; T = transfer line with static mixers then
5 extrusion through a slit die to make film.
** For unstretched PET film, the control OPV is the mean of values for seven different samples, each run in duplicate; the standard deviation is 0.49. For stretched film, the control OPV is the mean of values for 27 different samples, each run in duplicate; the standard deviation is 0.41.
0
Example 2 Films prepared from commercially available PET resin (Melinar® Laser+ brand PET resin) which contained zero or nominally 2 \vt% of the sodium salt of
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methyl 4-hydroxybenzoate were extruded using a twin screw extruder. Oxygen permeability values were determined for both as-cast and biaxially stretched films, as in Ex. 1. Films were stretched to 3.5X by 3.5X at 9000%/min, 100°C. The OPV for the stretched film containing the additive was 5.18 cc-mils/100 sq. in-24 hr-atm stretched, versus 6.56 for stretched PET film without an additive; the additive therefore produced a 26.6% improvement in oxygen barrier performance.
Example 3
PoIy(propylene terephthalate) ("3GT") films containing zero and nominally 10 3 wt% methyl 4-hydroxybenzoate ("MHB") were prepared using a twin screw extruder and a barrel setting of 240°C. Films containing no MHB and nominally 3 wt% MHB were stretched 3X by 3X at 55°C and 53°C respectively. Oxygen permeability values for the 3GT films containing MHB were 4.72 cc-mil/100 sq. in-24 hr-atm for cast film and 3.59 cc-mil/100 sq. in-24 hr-atm for stretched film, versus the 3GT control OPV 15 values of 8.56 for as-cast film and 5.30 for stretched film. Water vapor permeability at 38°C for as-cast films containing MHB was 2.22 g-mil/100 sq. in-24 hr and 1.95 g-mil/100 sq. in-24 hr for stretched film, versus the 3GT control values of 3.50 for as-cast film and 2.24 for stretched film.

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Example 4
A blend of MHB with PET (IV 0.86) was prepared via twin-screw extrusion at 245°C. The resulting blend, which was a concentrate, had an IV of 0.86 dL/g, and contained 6.9% MHB by NMR analysis. The blend was dried overnight at 100°C under vacuum and combined with standard commercial PET bottle resin (IV 25 0.83 dL/g, dried 6 hours at 150°C). 26g sample preforms were then injection molded using a Nissei ASB 50 single stage injection stretch blow molding machine, using barrel temperatures of about 265°C and a total cycle time of approximately 30 seconds. The preforms were immediately blown into 500 mL round-bottomed bottles with a blow time of 5 seconds. All other pressure, time and temperature set-30 points were typical for standard PET bottle resin. A control set of bottles made only





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of the standard PET bottle resin (IV 0.83, dried 6 hours at 150°C) was prepared under the same conditions. The oxygen permeation value for panels cut from bottles containing 1.97 wt% methyl 4-hydroxybenzoate ("MHB") was determined to be 3.69 cc-mils/100 sq. in-24 hr-atm versus 5.73 for a control PET bottle panel. Carbon dioxide permeation values were 9.65 cc-mil/100 sq. in-24 hr-atm. for the bottle with MHB and 14.62 for the control panel.
Example 5
Commercially available PET film containing 4 wt% MXD-6 6007 nylon (Mitsubishi Gas Chemical Corp.) and, nominally, 3 wt% MHB was extruded along with a PET control film. The films were biaxially stretched 3.5X by 3.5X as in Example 1. The OPV for the film containing the additives was 2.59 cc-mils/l 00 sq. in-24 hr-atm, versus the control film"s OPV of 7.14.
Example 6
A diester of p-hydroxybenzoic acid ("HBA") (corresponding to Formula B where R1 = CH2CH2) was synthesized from the reaction of stoichiometric mixtures of HBA and ethylene glycol in diphenyl ether with the catalyst butyl stannoic acid. PET films containing 0 and 4.55 wt% of this diester were extruded and then stretched as in Example !. The OPV of the film containing the diester was 3.93 cc-mils/100 sq. in-24 hr-atm, and the OPV of the PET film without the diester was 7.32 cc-mils/100 sq. in-24 hr-atni.
Example 7
The benzamide of HBA (corresponding to Formula C where R = phenyl) was synthesized from the reaction of MHB with benzylamine. An extruded PET film containing a nominal 3 wt% of this benzamide and stretched as in Example 1 exhibited an OPV of 5.00 cc-mil/100 sq. in-24 hr-atm, vs. a PET control film which had an OPV of 6.94.
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Example 8
The diamide of HBA (corresponding to Formula D where R1 = CH2CH2) was synthesized from the reaction of 4-acetoxybenzoyl chloride with ethylene diamine, followed by basic hydrolysis of the acetate groups. An extruded PET film containing a nominal 3 wt% of this diamide and stretched as in Example 1 exhibited an OPV of 5.46 cc-mil/lGO sq. in-24 hr-atm whereas a PET control film exhibited an OPV of 7.79.
Example 9
10 A diesterof HBA and methylene glycol was synthesized from the reaction of
stoichiometric mixtures of HBA and triethylene glycol in diphenyl ether with the catalyst butyl stannoic acid. PET film containing 6.49 wt% of this diester (determined by NMR) was extruded and stretched as in Example 1. The OPV for this film was 4.0 cc-mil/100 sq. in-24 hr-atm whereas a PET control film exhibited an
1) OPV of 7.04.
Example 10
A blend of 97 wt% dried PET resin (Melinar® Laser*- brand PET resin) and 3 wt% methyl 4-hydroxybenzoate was mixed thoroughly and added to the hopper of a 20 6 GZ. injection molding machine. Standard 1/8 thick tens ile i^ars were molded W"tii the following machine set-up: barrel temp 255°C, mold temp: 20°C/20°C, cycle time: 20 sec/20 sec, injection pressure: 5.5 MPa, RAM speed: FAST, screw speed: 60 rpm, and back pressure: 345 kPa. Intrinsic viscosity was measured on sections which were cut from the center of the bars using a 0.4% solution in 1:1 TFA: CH2C12 at 19°C. 2 5 The I.V. was 0.73 dL/g vs. a control PET resin sample molded under identical conditions which had an I.V. of 0.73 dL/g.
In contrast, the I.V. of the bottle from Example 4, containing 1.97 wt% MHB and prepared from a pre-compounded MHB/PET concentrate, was 0.464 dL/g, and the control PET bottle I.V. was 0.76 dL/g. This example demonstrates that : 0 degradation of the polymer composition"s molecular weight (as evidenced by I.V.) can be avoided by selection of appropriate processing conditions.
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Example 11
Laser+ PET films containing 0 to 3.46 wt% MHB were prepared by extrusion compounding. Two of these were also biaxially stretched as in Example 1. Water vapor permeabilities (g-mil/100 sq. in - 24 hr) at 38°C, 100% relative humidity are tabulated below.


MHB Content (wt%) Water Vapor Permeability, As-Cast Film Water Vapor Permeability, Stretched Film
0 4.31 2.43
0.56 3.87 ~
1.91 3.42 1.69
3.46 2.93
Example 12
Films of Lexan® 134r polycarbonate, Ultem® 1000 polyetherimide (both 10 manufactured by General Electric), and Radel® polyethersulfone (manufactured by Boedeker Plastics, Inc.) containing 0 or nominally 5 wt% n-propyl p-hydroxybenzoate (PHB) were melt-pressed at 260, 270, and 270°C, respectively. Oxygen permeabilities (OPV) at 30°C are tabulated below.

Polymer OPV, no PHB (cc-mil/l00 sq. in. 24 hr) OPV,nom.5 wt% PHB (cc-mil/l00 sq. in. 24 hr)
Lexan® 134r polycarbonate 232.5 138.7
Ultem® 1000 polyetherimide 48.05 24.45
Radel® polyethersulfone 89.79 52.11
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Example 13
Films of a copolymer of composition 7.4% poly(isosorbide terephthalate)-co-92.6%) poIy(ethylene terephthalate), prepared according to U.S. Patent No. 5,959,066, containing 0 to 3.85 wt% MHB were prepared by extrusion compounding, then 5 biaxially stretched 3.5X by 3.5X at 90°C (95°C for 0% MHB), 9000%/min. Oxygen permeabilities are tabulated below.

MHB Wt% OPV (cc-mil/100 sq. in/24 hr-atm)
0 8.22
0.70 8.02
2.24 5.57
3.85 3.98
19

WE CLAIM:
1. A polymer composition comprising (1) a base which is selected from thermoplastic homopolymers, random or block copolymers and a blend or blends of such homopolymers and copolymers and (2) a concentration of from 0.1% by wt. upto 20% by wt. of the composition of a gas barrier-enhancing molecular addictive or mixture of such gas barrier-enhancing molecular additives selected from the group consisting of:
(a) monoesters of hydroxybenzoic acid and hydroxynaphthoic acid of the formula (A)

wherein R is C1 - C8 alkyl, benzyl, phenyl or naphthyl; Ar is substituted or unsubstituted phenylene or naphthylene; or formula (AA) where M is a cation such as, but not limited to, sodium, ammonium, tetraalkyl ammonium, potassium, calcium, magnesium or zinc;
20
(b) diesters of hydroxybenzoic acid of the formula (B)


wherein Ar is as defined above, and Ri is C1-C4 alkyl, (CH2CH2O)kCH2CH2 where k is 1 or more, benzyl, phenyl or naphthyl; or formula (BB) where M is as defined above.
(c) monoamides of hydroxybenzoic acid and hydroxynaphthoic acid of the formula (C)

24
wherein R and Ar are as defined above; or formula (CC) where M is as defined above, (d) diamides of hydroxybenzoic acid of the formula (D)


wherein Ar is as defined above, and R2 is Ci -Cs alkyl, (CH2CH2O)kCH2CH2 where k is 1 or more, benzyl, phenyl or naphthyl; or formula (DD) where M is as defined above. (e) ester-amides of hydroxybenzoic acid of the formula (E)

where Ar is as defined above and R3 is C1 - Cs alkyl, C1 - Cs dialkyl, (CH2CH2O)kCH2CH2 where k is 1 or greater, benzyl, phenyl or naphthyl, or formula (EE) where M is as defined above.
2. The polymer composition as claimed in claim 1, wherein the base polymer is a polyester homopolymer or copolymer which contains structural units derived from one or more organic diacids or their corresponding esters selected from the group consisting of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acids, hydrexybenzoic acids, hydrexynaphthoic acids, cyclohexane dicarboxylic acids, succinin acid, glutaric acid, adipic acid, sebacic acid, 1, 12-dodecane dioic acid and the derivatives thereof which are the dimethyl, diethyl,
22

or dipropyl esters or acid chlorides of the dicarboxylic acids and one or more diols selected from the group consisting of ethylene glycol, 1-3-propane diol, naphthalene glycol, 1,2-propanediol, 1,2-, 1,3-, and 1,4-cyclohexane dimethanol, diethylene glycol, hydroquinone, 1,3-butane diol, 1,5-pentane diol, 1,6-hexane diol, triethylene glycol, resorcinol, and long chain diols and polyols which are the reaction products of diols or polyols with alkylene oxides, and the gas barrier-enhancing molecular additive or mixture of such gas barrier-enhancing molecular additives are present in the polymer composition at a total concentration of from 0.1% by wt. up to about 20% by wt of the composition.
3. The polymer composition as claimed in claim 2, wherein the polyester homopolymer or copolymer is polyethylene terephthtalate.
4. The polymer composition as claimed in claim 1, wherein the base polymer is selected from polycarbonates, polyetherimides and polyethersulfones.
[DR. ANUSHRI GUPTA]
OF REMFRY 8B SAGAR
ATTORNEY FOR THE APPLICANTS
5. An article of manufacture which is a sheet, a film or a container which is formed from the composition as claimed in claim 1. Dated this on 27/07/2005

13

Sheet No. ...3.
Box No.V DESIGNATION OF STATES
The following designations are hereby made under Rule 4.9(a) (mark the applicable check-boxes; at least one must be marked):
Regional Patent
X AP ARIPO Patent: GH Ghana, GM Gambia, KE Kenya, LS Lesotho, MW Malawi, SD Sudan, SZ Swaziland, UG Uganda, ZW Zimbabwe, and any other State which is a Contracting State of the Harare Protocol and of the PCT
X EA Eurasian Patent: AM Armenia, AZ Azerbaijan, BY Belarus, KG Kyrgyzstan, KZ Kazakhstan, MD Republic of Moldova, RU Russian Federation, TJ Tajikistan, TM Turkmenistan, and any other State which is a Contracting State of the Eurasian Patent Convention and of the PCT
X EP European Patent: AT Austria, BE Belgium, CH and LI Switzerland and Liechtenstein, CY Cyprus, DE Germany, DK Denmark, ES Spain, FI Finland, FR France, GB United Kingdom, GR Greece, IE Ireland, IT Italy, LU Luxembourg, MC Monaco, NL Netherlands, PT Portugal, SE Sweden, and any other State which is a Contracting State of the European Patent Convention and of the PCT
X OA OAPI Patent: BF Burkina Faso, BJ Benin, CF Centra! African Republic, CG Congo, CI Cote d"lvoire, CM Cameroon,
GA Gabon, GN Guinea, GW Guinea-Bissau, ML Mali, MR Mauritania, NE Niger, SN Senega!, TD Chad, TG Togo,
and any other State which is a member State of OAPI and a Contracting State of the PCT (if other kind of protection or
treatment desired, specify on dotted litis)
National Patent (if other kind of protection or treatment desired, specify on dotted line):


LS Lesotho
LT Lithuania LU Luxembourg LV Latvia
MD Republic of Moldova
MG Madagascar
MK The former Yugoslav Republic of Macedonia
AL Albania


AM Armenia
AT Austria
AU Australia
AZ Azerbaijan

BA Bosnia and Herzegovina
BB Barbados
MN Mongolia
MW Malawi
MX Mexico
NO Norway
NZ New Zealand
Poland
Portugal
Romania
Russian Federation
Sudan
Sweden
Singapore
Slovenia
Slovakia
Sierra Leone
Tajikistan
TM Turkmenistan
TR Turkey
TT Trinidad and Tobago
UA Ukraine
UG Uganda
US United States of America
BG Bulgaria
BR Brazil
BY Belarus
CA Canada
CH and LI Switzerland and Liechtenstein
PL
PT
RO
RU
SD
SE
SG
SI
SK
SL
TJ
CN China
CU Cuba
CZ Czech Republic
DE Germany
DK Denmark ,
EE Estonia
ES Spain
FI Finland
GB United Kingdom
GD Grenada
GE Georgia
GH Ghana
GM Gambia
HR Croatia
HU Hungary
ID Indonesia
IL Israel
IN India
UZ Uzbekistan VN Viet Nam YU Yugoslavia ZW Zimbabwe
IS Iceland
JP Japan
KE Kenya
KG Kyrgyzstan
KP Democratic People"s Republic of Korea
KR Republic of Korea
KZ Kazakhstan
EC Saint Lucia
LK Sri Lanka
LR Liberia
Check-boxes reserved for designating States (for the purposes of a national patent) which have become party to the PCT after issuance of this sheet:
□ "
D
D
Precautionary Designation Statement: In addition to the designations made above, the applicant also makes under Rule 4.9(b) all other designations which would be permitted under the PCT except any designation(s) indicated in the Supplemental Box as being excluded from the scope of this statement. The applicant declares that those additional designations are subject to confirmation and that any designation which is not confirmed before the expiration of 15 months from the priority date is to be regarded as withdrawn by the applicant at the expiration of that time limit. (Confirmation of a designation consists of the fling ofa notice specifying thai designation
| and the payment of the designation and confirmation fees. Confirmation must reach the receiving Office within the i 5-month lime limit.)
Form PCT/RO/101 (second sheet) (January 1999) uBaisiar 1999, Pom PCTREQ See Notes to the request form


X The receiving Office is requested to prepare and transmit to the International Bureau a certified copy
of the earlier application(s) (only if the earlier application was filed with the Office which for the
purposes of the present international application is the receiving Office) identified above as itcm(s): _(1) (2)____
* Where the earlier application is an ARIPO application, it ix mandatory to indicate in the Supplemental Box at least one country parly to the Paris Convention for the Protection of Industrial Property for irhich that earlier application wax filed (Rule 4.10(b)(ii)J. See Supplemental Bar.
Box No. VII INTERNATIONAL SEARCHING AUTHORITY
Choice of International Searching Authority (ISA) Request to use results of earlier search; reference to that search (if an earlier
(if two Or more International Searching Authorities are I search has keen carriedout hy or requested from the InternationalSearching Authority): J
competent to carry out the international search, indicate the
Authority chosen; the two-letter code may be used): Date (day/month/year) Number Country (or regional Office)
ISA/EP )
Box No. VIII CHECK LIST: LANGUAGE OF FILING
This international application contains This international application is accompanied by the item(s) marked below: the following number of sheets: 1. X fee calculation sheet
request 4 2. [] separate signed power of attorney
description (excluding) 3. [X] copy of general power of attorney; reference number, if any:
sequence listing part) : 16 4. [] statement explaining lack of signature
claims : 6 5. □ priority document(s) identified in Box No. VI as -itcms(s):
abstract . 1 6. [] translation of international application into (language):
drawings : 0 7. separate indications concerning deposited microorganism or other biological material
sequence listing part 8. nucleottde and/or amino acid sequence listing in computer readable form
of description : 0 __
9. X other (specify): TRANSMITTAL LETTER
Total number of sheets : 27 .,
Figure of the drawings which Language of filing of the
should accompany the abstract: international application: ENGLISH"
Box No. IX SIGNATURE OF APPLICANT OR AGENT
Next to each signature, indicate the name of the person signing and the capacity in which the person signs (if such capacity is not obviousfrom reading the request).
E.I. DU PONT DE NEMOURS AND COMPANY
BY-
ROGERA. BOWMAN
ASSISTANT SECRETARY-PATENT BOARD

For receiving Office use only
1. Dale of actual receipt of the purported international application:
3. Corrected date of actual receipt due to later but
timely received papers or drawings completing the
purported international application:
4. Date of timely receipt of the required corrections under PCT Article 11(2):

2. Drawings: received:
not received:



5. International Searching Authority ISA/ (if two or more are competent):

6.



Transmittal of search copy delayed until search fee is paid

For International Bureau use only
Date of receipt of the record copy by the International Bureau:

Form PCT/RO/101 (last sheet) (July 1998; reprint January 1999)

LeoaiSiar 199B, Fonn PCTREQ See Notes to the request form

Documents:

833-mumnp-2004-claims(granted)-(1-11-2007).doc

833-mumnp-2004-form 2(granted)-(1-11-2008).doc

833-MUMNP-2005-CANCELLED PAGES(1-11-2007).pdf

833-MUMNP-2005-CLAIMS(2-8-2005).pdf

833-MUMNP-2005-CLAIMS(AMENDED)-(1-11-2007).pdf

833-mumnp-2005-claims(cancelled).pdf

833-mumnp-2005-claims(granted)-(01-11-2007).pdf

833-mumnp-2005-claims(granted)-(22-2-2008).pdf

833-mumnp-2005-claims.doc

833-mumnp-2005-claims.pdf

833-MUMNP-2005-CORRESPONDENCE(18-12-2007).pdf

833-mumnp-2005-correspondence(31-12-2007).pdf

833-mumnp-2005-correspondence(ipo)-(15-12-2006).pdf

833-MUMNP-2005-CORRESPONDENCE(IPO)-(4-4-2008).pdf

833-mumnp-2005-correspondence(ipo).pdf

833-mumnp-2005-correspondence-others.pdf

833-mumnp-2005-correspondence-received-ver-240106.pdf

833-mumnp-2005-correspondence-received-ver-251105.pdf

833-mumnp-2005-correspondence-received.pdf

833-mumnp-2005-correspondence-send.pdf

833-mumnp-2005-correspondence.pdf

833-mumnp-2005-description (complete).pdf

833-MUMNP-2005-DESCRIPTION(COMPLETE)-(2-8-2005).pdf

833-mumnp-2005-description(granted)-(22-2-2008).pdf

833-mumnp-2005-description(granted).doc

833-mumnp-2005-description(granted).pdf

833-mumnp-2005-form 1(02-08-2005).pdf

833-mumnp-2005-form 1.pdf

833-mumnp-2005-form 13(01-11-2007).pdf

833-MUMNP-2005-FORM 13(1-11-2007).pdf

833-mumnp-2005-form 13.pdf

833-mumnp-2005-form 18(25-01-2006).pdf

833-mumnp-2005-form 18.pdf

833-MUMNP-2005-FORM 2(COMPLETE)-(2-8-2005).pdf

833-mumnp-2005-form 2(granted)-(01-11-2007).pdf

833-mumnp-2005-form 2(granted)-(22-2-2008).pdf

833-mumnp-2005-form 2(granted).doc

833-mumnp-2005-form 2(granted).pdf

833-MUMNP-2005-FORM 2(TITLE PAGE)-(2-8-2005).pdf

833-mumnp-2005-form 2(title page)-(granted)-(22-2-2008).pdf

833-mumnp-2005-form 2(title page).pdf

833-mumnp-2005-form 3(01-11-2007).pdf

833-MUMNP-2005-FORM 3(2-8-2005).pdf

833-mumnp-2005-form 3(27-07-2005).pdf

833-mumnp-2005-form 3.pdf

833-mumnp-2005-form 5(27-07-2005).pdf

833-mumnp-2005-form 5.pdf

833-mumnp-2005-form pct-ipea-409(02-08-2005).pdf

833-mumnp-2005-form-1.pdf

833-mumnp-2005-form-pct-ipea-408.pdf

833-mumnp-2005-form-pct-ipea-seperate sheet-408.pdf

833-mumnp-2005-form-pct-ro-101.pdf

833-MUMNP-2005-GENERAL POWER OF ATTORNEY(2-8-2005).pdf

833-mumnp-2005-genrel power of attorney.pdf

833-mumnp-2005-pct-international examination report.pdf

833-mumnp-2005-pct-other.pdf

833-mumnp-2005-pct-request.pdf

833-mumnp-2005-pct-wo international publication report a1.pdf

833-mumnp-2005-petition under rule 137(1-11-2007).pdf

833-mumnp-2005-power of attorney.pdf

833-mumnp-2005-power of authority(01-11-2007).pdf

833-mumnp-2005-power of authority(13-09-2005).pdf

833-mumnp-2005-power of authority(24-07-2005).pdf

833-mumnp-2005-us-patent.pdf

833-MUMNP-2005-WO INTERNATIONAL PUBLICATION REPORT(2-8-2005).pdf


Patent Number 215213
Indian Patent Application Number 833/MUMNP/2005
PG Journal Number 13/2008
Publication Date 28-Mar-2008
Grant Date 22-Feb-2008
Date of Filing 02-Aug-2005
Name of Patentee E.I. DU PONT DE NEMOURS AND COMPANY
Applicant Address 1007 MARKET STREET, WILMINGTON, DELAWARE 19898 USA
Inventors:
# Inventor's Name Inventor's Address
1 IRENE GREENWALD PLOTZKER 2307 WYNWOOD DRIVE, WILMINGTON, DELAWARE 19810
2 SAMUEL TACITUS D'ARCANGELIS 2522 TRAYNOR AVENUE, CLAYMONT, DELAWARE 19703
3 THOMAS MICHAEL FORD 3112 CENTERVILLE ROAD, GREENVILLE, DELAWARE 19807
4 KENNETH GEORGE SHARP 164 HAMMILTON ROAD, LANDENBERG, PENNSYLVANIA 19350
PCT International Classification Number B65D65/38 C08K5/134
PCT International Application Number PCT/US00/21777
PCT International Filing date 2000-08-10
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/148,537 1999-08-12 U.S.A.
2 09/634,288 2000-08-09 U.S.A.