CA1040338A - Polyethylene terephthalate/terpolymer blends; films, sheets, and articles made using such blends; and method of making trays using such sheets - Google Patents
Polyethylene terephthalate/terpolymer blends; films, sheets, and articles made using such blends; and method of making trays using such sheetsInfo
- Publication number
- CA1040338A CA1040338A CA208,306A CA208306A CA1040338A CA 1040338 A CA1040338 A CA 1040338A CA 208306 A CA208306 A CA 208306A CA 1040338 A CA1040338 A CA 1040338A
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- CA
- Canada
- Prior art keywords
- composition according
- polyethylene terephthalate
- sheets
- terpolymer
- blends
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
- C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
-
- 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
-
- 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
- C08K3/34—Silicon-containing compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
- C08L23/08—Copolymers of ethene
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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)
- Compositions Of Macromolecular Compounds (AREA)
- Table Devices Or Equipment (AREA)
Abstract
Abstract of the Disclosure This invention is a composition for sheets, films coatings, containers or trays comprising a blend of polyethylene terephthlate (as defined herein) and a terpolymer of ethylene, vinyl ester and acrylic or methacrylic acid. Articles, such as cooking containers or trays, are made by using such polyethylene terephthlate/
terpolymer blends or made using sheets made from such blends.
Such trays may be used for cooking food at temperatures up to about 200°C. Methods are disclosed for making trays including thermoforming sheets made from such blends.
terpolymer blends or made using sheets made from such blends.
Such trays may be used for cooking food at temperatures up to about 200°C. Methods are disclosed for making trays including thermoforming sheets made from such blends.
Description
1tJ~(~3~3 This invention is a composition for sheets, fllms, coatings, containers or trays comprising a blend of polyethylene terephthalate (as defined herein) and a terpolymer of ~thylene, vinyl ester and acrylic or methacrylic acid.
In the prior art, unmodified polyethylene tere-phthalate has been used in making shaped and other arti-cles which utilize its toughness, its formability, its durability and its chemically and biologically inert behavior. For some uses, however, such unmodlfled poly~
ethylene terephthalate has properties or deflciencies which make it unsuitable.
Accordingly, specialized blends have been developed to meet particular needs. For example, poly-ethylene terepht.halate with copolymer~ of ~ -oleflns and vinyl esters have been developed to enhance mechanic~l properties, such as hardness, lmpact strength, tou~hness and abrasion reslstance.
According to the present invention, there ls provided a composition for sheets, films, coatings or containers comprising a blend of polyethylene tereph-thalate wlth a polymeric additive that ls malnly but no~
entirely based on ethylene, characterized in that the blend includes, by weight, 99 to 95% polyethylene tereph-I thalate and 1 to 5% of a terpolymer of at least 65% ethy-¦ lene wlth (a) at least 5% of a vinyl ester of a 1-6 carbon saturated monobasic aliphatlc carboxylic acld and (b) 0.1 to 10% of acrylic and/or methacrylic ~cl~. It iB prcferred to uee 3% of the terpolymer.
Preferred vinyl esters are the vinyl esters of 1 to 4
In the prior art, unmodified polyethylene tere-phthalate has been used in making shaped and other arti-cles which utilize its toughness, its formability, its durability and its chemically and biologically inert behavior. For some uses, however, such unmodlfled poly~
ethylene terephthalate has properties or deflciencies which make it unsuitable.
Accordingly, specialized blends have been developed to meet particular needs. For example, poly-ethylene terepht.halate with copolymer~ of ~ -oleflns and vinyl esters have been developed to enhance mechanic~l properties, such as hardness, lmpact strength, tou~hness and abrasion reslstance.
According to the present invention, there ls provided a composition for sheets, films, coatings or containers comprising a blend of polyethylene tereph-thalate wlth a polymeric additive that ls malnly but no~
entirely based on ethylene, characterized in that the blend includes, by weight, 99 to 95% polyethylene tereph-I thalate and 1 to 5% of a terpolymer of at least 65% ethy-¦ lene wlth (a) at least 5% of a vinyl ester of a 1-6 carbon saturated monobasic aliphatlc carboxylic acld and (b) 0.1 to 10% of acrylic and/or methacrylic ~cl~. It iB prcferred to uee 3% of the terpolymer.
Preferred vinyl esters are the vinyl esters of 1 to 4
- 2 -~.
, ., .,., car~on saturated monobaslc aliphatic carboxylic acids, especially vinyl acetate; preferred quantity of vinyl ester in the terpolymer is at least 12~, especially 20 to 30%. Preferred quantity of acrylic or methacrylic acid in the terpol~-mer is 0.5% to 7%, especially ~.5%
to 3%. The most preferred terpolymer consists of 72%
ethylene, 27% vlnyl acetate and 1% methacrylic acid.
Sheets made from the polyethylene terephthalate/
terpolymer blends of this invention have been round to be particularly useful for making thermoformed trays of greater toughness and with greater freedom from embrittle-ment or sagging after heating, at temperatures up to , about 200C., for example, as compared to trays of un-modlfied polyethylene terephthalate or of polyethylene terephthalate with prevlously used modifiers. Other beneflts which arise from these sheets as used ln thermo-formed structures or trays include more rapld crystalli-zatlon, providing better form stability in newly-formed structures, as well as improved mold release and forming properties. Further, we have found that trays made uslng sheets of such polyethylene terephthalate/terpolymer blends may be formed in known vacuum thermoforming equip-ment at a reduced cycle time, as compared to trays made using sheets of known blends or of unmodified polyethylene terephthalate.
The requirements for a satisfactory, versatile tray are that it should permit cooking of its contents up to about 200C., and should have thermal stability and not become too brittle or be prone to cracking upon heating. Further, it should not become distorted upon heatlng.
_ 3 _ lQ4~33~3 Previou~ly lt ha~ been the practlce to rorm tray~ of heat-~ealable polymer~, ~uch a~ vlnyl~ ~nd olefln~, to facllltate ~ecurlng lld~ thereon, but these iln general do not po~se~-the thermal ~tablllty requlred for reheatlng ~ood~. Formed tray~ of alumlnum foll have been employed, but these lack verJatlllty ln that they are unJultable ~or u~e ln mlcrowave oven~, for example, Compo~itlonJ accordlng to the pre~ent lnventlon have been found u~eful ln the form of cooklng contalnerJ
or tray~ for packaglng rood and for Jub~equent cooklng and reheatlng Or rood,.
Terpolymer~ wlthln the ~cope of tho~e userul ln the pre~ent lnventlon lnclude tho~e de~crlbed ln detall ln U.S. Patent 3 215 678 to Adelman et al. The degree o~ improvement in propertle~ obtalned by thlJ
lnventlon appear~ to be relatlvely ln~en~ltlve to varlatlon Or the melt lndex o~ the terpolymer u~ed ln thl~ lnventlon.
Polyethylene terephthalate whlch can be u~ed ln the blend of thl~ lnventlon lnclude~ (a~ polymer~ whereln at lea~t 97~ o~ the polymer contaln~ the repeatlng ethyle~e terephthalate unlt~ Or the rormula:
i. O O
-0CH2CH20C ~
wlth the remalnder belng mlnor amount~ of e~ter-rormlng component~, and (b~ copolymer~ o~ ethylene terephthalate whereln up to 10 mole percent o~ the copolymer 1~ pre-pared from the monomer unlt~ o~ dlethylene glycol; pro-pane-1,3-dlol; butane-1,4-diol; polytetramethylene glycol;
polyethylene glycol; polypropylene glycol; 1,4-hydroxy-i 30 methylcyclohexane; and the llke, ~ub~tltuted for the ,~ , 1 ~1 --4--,, ~. , 1()4V338 glycol molety in the preparation of the copolymer and/or l~ophthallc; blbenzoic; naphthalene 1,4- or 2,6-dlcarboxyllc;
adlplc; sebacic; decane-l,lO-dicarboxylic acid; and the like, - substituted for the acid moiety in the preparation of the copolymer.
Specific limits on the amount of comonomer are governed by the polymer glass transltion temperature since lt has been fou~d that copolymers havlng a glass transl-tlon temperatu~e below about 50C. generally have reduced mechanical properties. Thls generally corresponds to the additlon of no more than 10 mole percent comonomer. One exceptlon to thls ls the additlon of blbenzolc acld where , the copolymer ~lass transltlon temperature remalns above 50~C. even when the copolymer contalns more than 10 mole percent blbenzoic acid. Other exceptlons will be obvlous to the artlsan. alass transitlon temperature~ are a~
determined using standard differentlal scannlng calorl-metry technlques.
l In the compositlons of thls lnventlon the poly-¦ 2~ ethylene terephthalate may contaln from 0.1 to 1.5% by weight of afinely divided inert mineral solld ~ubstance, or a nucleating agent. Calcium carbonate, aluminum ~lllcates and talc are examples of sultable nucleatlng agents. If deslred, the polyethylene terephthalate may contaln a nucleating agent and opaclfylng agent, 8uch as tltanlum dloxlde. Preferably, the polyethylene tereph-thalate contalns 1% talc and 1.5% tltanlum dloxlde. The inherent viscosity of the blend composltion preferably ls , from 0.70 to 0.95 and for a shaped article therefrom, ~; 30 inherent viscosity preferably is from 0.65 tc 0.85.
: . .
. ~
, .. . . . . .
()338 used herein, inherent vlsco~lty i8 b~ed on 1% concentration of polymer ln a 75/25 welght percent ~olutlon of trlfluoroacetlc acld/methylene chlorlde, respectively, at 30C. and i8 computed uslng the formula n~tur~l log (vl~co~lty of ~olution) Inherent Vl~co~lty = viscosity o~ ~olvent where C i8 the concentratlon ~xpre~ed ln grams oi poly-mer per lO0 milllllterJ of ~olution.
In preparlng the compo~ltion~ o~ the pre~ant lnvention, the component~ ~hould be pre-dried at tempera-ture~ and pre~ures such a8 to obtain maximum drying whlle avoldlng agglom¢ratlon. They may be blended by meterlng the indlvldual ~tream~ lnto a ~lngle or twin ~crew extruder ~hlch serve~ to melt and mix the components, The blend, thus mlxed and melted, may then be extruded by known method~.
Sheet~, lncludlng ca~t amorphou~ ~heet~, or fllm~ made from the blend~ o~ the ln~tant inventlon may be prepared by kno~n ~methods and devlce~, e.g., as ln U.S. Patent 2 823 421 to ~carlett, ~ny number Or thermoformlng method~ and devlce~
may be u~ed whereln a ~heet, sultably clamped, 1~ drawn or pu~hed lnto a mold u~lng the vacuum whereby ~uch ~heet take~ the ~hape o~ the lnner ~urrace Or the mold whlch lt ; 1~ brought lnto contact wlth to form the molded artlcle or contalner. The method~ may lnclude (l) stralght i,! vacuum formlng (2~ drape formlng (3~ match-mold formlng (4) ~llp-ring formlng (5~ plug-assl~t vacuum formlng (6~ plug-a~slst pressure formlng (7~ ~nap-vacuum forming ` .
, ~
1~3'~ 3~
, . . .
(8~ blllo~ rormlng (9~ trapped-~heet, contact-heat pre~-- ~ure rormlng and (10~ preheat, plug-a~cl~t pre~ure ~orm-'.f' ' lng, Mean~ and dctail~ ror Juch thermo~ormlng may be ` found ln copendlng Canadlan Patent ~ppllcatlon 193 039, ~ led February 20, 1974.
, Improvement~ brought abcut by the ln~tant lnve-ntlon may be note~ by rererrlng to the rollo~lng T~ble I:
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,, a.~ ~ ~I C~ cu m,~ C~J ~ cr ~,~ o CU C~J
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~ e a) P~ s o ~N ~ --O ~ ~ O
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i~ ~ S ~I S~; ~i ~ C ~ ~ ~ ~ _I ~( ~. _ ~ 0 Q~ ~ E .1 ~1 ~: O D
i~ ~n ~) S ~ ~ ~ ~ - h _I o ~ ~1, ,1 ~ C C --I ~ Q ~ ' 0 .; 0 ~I S c a 0 ~ x ~ 0 ~o ~ o P~ ~ . o h ~ ~ m ~ C o o o ~ ~ ~D
, a~ h H ~ ~ V ~ C~ {U CJ~ 0 , ~ a~
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. 1~14~3338 ; The drawing i9 a graph comparing impact strengths of sheets made from a polyethylene terephthalate/terpolymer blend of thls lnvention with ~heets made from a polyethylene terephthalate/cop~lymer blend at various lnherent visc~sities, , The polyethylene terephthalate/terpolymer blend sheets tested contained 96~ polyethylene terephthalate and 3% of the terpolymer which consisted of 72% ethylene, 27% vinyl acetate, and 1% methacrylic acid, while the poly-ethylene terephthalate/copolymer blend sheets contained 96% polyethylene terephthalate and 3% of the copolymer which consisted of 72~ ethylene and 28~ vinyl acetate, Both the polyethylene terephthalate/terpolymer and poly-ethylene terephthalate/copolymer blends contained 1 talc, In making the sheets tested, the polyethylene terephthalate/terpolymer and polyethylene terephthalate/
copolymer blends were extruded onto a co~led surface, after whlch the a~orphous sheets formed thereby were strlpped from the sur~ace, These sheets were then brought lnto contact with a heated surface and crystallized at 150C for 100 seconds, Such sheets, after crystalliza-tlon, were then tested at room temperature using a Gardner impact tester, The results of these tests appear in the graph whlch clearly shows the lmprovements ln impact strengths brought about by the instant invention, The following Example and Table II also show tray forming and tray durability improvements brought about by this inventlon, Example SAmple~ o~ polyethylene terephthalRte ~ere ~)4()338 blended ~ith a terpolymer Or 72~ ethylene, 27~ vlnyl acetate and 1% methacryllc acid and compared to poly-ethylene terephthalate samples blended wlth a copolymer of 72% ethylene and 28% vinyl acetate with respect to tray formability ar.d durability after oven heating.
All samples contained 96% polyethylene terephthalate,
, ., .,., car~on saturated monobaslc aliphatic carboxylic acids, especially vinyl acetate; preferred quantity of vinyl ester in the terpolymer is at least 12~, especially 20 to 30%. Preferred quantity of acrylic or methacrylic acid in the terpol~-mer is 0.5% to 7%, especially ~.5%
to 3%. The most preferred terpolymer consists of 72%
ethylene, 27% vlnyl acetate and 1% methacrylic acid.
Sheets made from the polyethylene terephthalate/
terpolymer blends of this invention have been round to be particularly useful for making thermoformed trays of greater toughness and with greater freedom from embrittle-ment or sagging after heating, at temperatures up to , about 200C., for example, as compared to trays of un-modlfied polyethylene terephthalate or of polyethylene terephthalate with prevlously used modifiers. Other beneflts which arise from these sheets as used ln thermo-formed structures or trays include more rapld crystalli-zatlon, providing better form stability in newly-formed structures, as well as improved mold release and forming properties. Further, we have found that trays made uslng sheets of such polyethylene terephthalate/terpolymer blends may be formed in known vacuum thermoforming equip-ment at a reduced cycle time, as compared to trays made using sheets of known blends or of unmodified polyethylene terephthalate.
The requirements for a satisfactory, versatile tray are that it should permit cooking of its contents up to about 200C., and should have thermal stability and not become too brittle or be prone to cracking upon heating. Further, it should not become distorted upon heatlng.
_ 3 _ lQ4~33~3 Previou~ly lt ha~ been the practlce to rorm tray~ of heat-~ealable polymer~, ~uch a~ vlnyl~ ~nd olefln~, to facllltate ~ecurlng lld~ thereon, but these iln general do not po~se~-the thermal ~tablllty requlred for reheatlng ~ood~. Formed tray~ of alumlnum foll have been employed, but these lack verJatlllty ln that they are unJultable ~or u~e ln mlcrowave oven~, for example, Compo~itlonJ accordlng to the pre~ent lnventlon have been found u~eful ln the form of cooklng contalnerJ
or tray~ for packaglng rood and for Jub~equent cooklng and reheatlng Or rood,.
Terpolymer~ wlthln the ~cope of tho~e userul ln the pre~ent lnventlon lnclude tho~e de~crlbed ln detall ln U.S. Patent 3 215 678 to Adelman et al. The degree o~ improvement in propertle~ obtalned by thlJ
lnventlon appear~ to be relatlvely ln~en~ltlve to varlatlon Or the melt lndex o~ the terpolymer u~ed ln thl~ lnventlon.
Polyethylene terephthalate whlch can be u~ed ln the blend of thl~ lnventlon lnclude~ (a~ polymer~ whereln at lea~t 97~ o~ the polymer contaln~ the repeatlng ethyle~e terephthalate unlt~ Or the rormula:
i. O O
-0CH2CH20C ~
wlth the remalnder belng mlnor amount~ of e~ter-rormlng component~, and (b~ copolymer~ o~ ethylene terephthalate whereln up to 10 mole percent o~ the copolymer 1~ pre-pared from the monomer unlt~ o~ dlethylene glycol; pro-pane-1,3-dlol; butane-1,4-diol; polytetramethylene glycol;
polyethylene glycol; polypropylene glycol; 1,4-hydroxy-i 30 methylcyclohexane; and the llke, ~ub~tltuted for the ,~ , 1 ~1 --4--,, ~. , 1()4V338 glycol molety in the preparation of the copolymer and/or l~ophthallc; blbenzoic; naphthalene 1,4- or 2,6-dlcarboxyllc;
adlplc; sebacic; decane-l,lO-dicarboxylic acid; and the like, - substituted for the acid moiety in the preparation of the copolymer.
Specific limits on the amount of comonomer are governed by the polymer glass transltion temperature since lt has been fou~d that copolymers havlng a glass transl-tlon temperatu~e below about 50C. generally have reduced mechanical properties. Thls generally corresponds to the additlon of no more than 10 mole percent comonomer. One exceptlon to thls ls the additlon of blbenzolc acld where , the copolymer ~lass transltlon temperature remalns above 50~C. even when the copolymer contalns more than 10 mole percent blbenzoic acid. Other exceptlons will be obvlous to the artlsan. alass transitlon temperature~ are a~
determined using standard differentlal scannlng calorl-metry technlques.
l In the compositlons of thls lnventlon the poly-¦ 2~ ethylene terephthalate may contaln from 0.1 to 1.5% by weight of afinely divided inert mineral solld ~ubstance, or a nucleating agent. Calcium carbonate, aluminum ~lllcates and talc are examples of sultable nucleatlng agents. If deslred, the polyethylene terephthalate may contaln a nucleating agent and opaclfylng agent, 8uch as tltanlum dloxlde. Preferably, the polyethylene tereph-thalate contalns 1% talc and 1.5% tltanlum dloxlde. The inherent viscosity of the blend composltion preferably ls , from 0.70 to 0.95 and for a shaped article therefrom, ~; 30 inherent viscosity preferably is from 0.65 tc 0.85.
: . .
. ~
, .. . . . . .
()338 used herein, inherent vlsco~lty i8 b~ed on 1% concentration of polymer ln a 75/25 welght percent ~olutlon of trlfluoroacetlc acld/methylene chlorlde, respectively, at 30C. and i8 computed uslng the formula n~tur~l log (vl~co~lty of ~olution) Inherent Vl~co~lty = viscosity o~ ~olvent where C i8 the concentratlon ~xpre~ed ln grams oi poly-mer per lO0 milllllterJ of ~olution.
In preparlng the compo~ltion~ o~ the pre~ant lnvention, the component~ ~hould be pre-dried at tempera-ture~ and pre~ures such a8 to obtain maximum drying whlle avoldlng agglom¢ratlon. They may be blended by meterlng the indlvldual ~tream~ lnto a ~lngle or twin ~crew extruder ~hlch serve~ to melt and mix the components, The blend, thus mlxed and melted, may then be extruded by known method~.
Sheet~, lncludlng ca~t amorphou~ ~heet~, or fllm~ made from the blend~ o~ the ln~tant inventlon may be prepared by kno~n ~methods and devlce~, e.g., as ln U.S. Patent 2 823 421 to ~carlett, ~ny number Or thermoformlng method~ and devlce~
may be u~ed whereln a ~heet, sultably clamped, 1~ drawn or pu~hed lnto a mold u~lng the vacuum whereby ~uch ~heet take~ the ~hape o~ the lnner ~urrace Or the mold whlch lt ; 1~ brought lnto contact wlth to form the molded artlcle or contalner. The method~ may lnclude (l) stralght i,! vacuum formlng (2~ drape formlng (3~ match-mold formlng (4) ~llp-ring formlng (5~ plug-assl~t vacuum formlng (6~ plug-a~slst pressure formlng (7~ ~nap-vacuum forming ` .
, ~
1~3'~ 3~
, . . .
(8~ blllo~ rormlng (9~ trapped-~heet, contact-heat pre~-- ~ure rormlng and (10~ preheat, plug-a~cl~t pre~ure ~orm-'.f' ' lng, Mean~ and dctail~ ror Juch thermo~ormlng may be ` found ln copendlng Canadlan Patent ~ppllcatlon 193 039, ~ led February 20, 1974.
, Improvement~ brought abcut by the ln~tant lnve-ntlon may be note~ by rererrlng to the rollo~lng T~ble I:
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i~ ~n ~) S ~ ~ ~ ~ - h _I o ~ ~1, ,1 ~ C C --I ~ Q ~ ' 0 .; 0 ~I S c a 0 ~ x ~ 0 ~o ~ o P~ ~ . o h ~ ~ m ~ C o o o ~ ~ ~D
, a~ h H ~ ~ V ~ C~ {U CJ~ 0 , ~ a~
:~ ,i N ~ _ ~ * *
. 1~14~3338 ; The drawing i9 a graph comparing impact strengths of sheets made from a polyethylene terephthalate/terpolymer blend of thls lnvention with ~heets made from a polyethylene terephthalate/cop~lymer blend at various lnherent visc~sities, , The polyethylene terephthalate/terpolymer blend sheets tested contained 96~ polyethylene terephthalate and 3% of the terpolymer which consisted of 72% ethylene, 27% vinyl acetate, and 1% methacrylic acid, while the poly-ethylene terephthalate/copolymer blend sheets contained 96% polyethylene terephthalate and 3% of the copolymer which consisted of 72~ ethylene and 28~ vinyl acetate, Both the polyethylene terephthalate/terpolymer and poly-ethylene terephthalate/copolymer blends contained 1 talc, In making the sheets tested, the polyethylene terephthalate/terpolymer and polyethylene terephthalate/
copolymer blends were extruded onto a co~led surface, after whlch the a~orphous sheets formed thereby were strlpped from the sur~ace, These sheets were then brought lnto contact with a heated surface and crystallized at 150C for 100 seconds, Such sheets, after crystalliza-tlon, were then tested at room temperature using a Gardner impact tester, The results of these tests appear in the graph whlch clearly shows the lmprovements ln impact strengths brought about by the instant invention, The following Example and Table II also show tray forming and tray durability improvements brought about by this inventlon, Example SAmple~ o~ polyethylene terephthalRte ~ere ~)4()338 blended ~ith a terpolymer Or 72~ ethylene, 27~ vlnyl acetate and 1% methacryllc acid and compared to poly-ethylene terephthalate samples blended wlth a copolymer of 72% ethylene and 28% vinyl acetate with respect to tray formability ar.d durability after oven heating.
All samples contained 96% polyethylene terephthalate,
3% of the terpolymer or copolymer, and 1% talc, all by weight based on the total weight of the blend.
The samples were prepared from carefully drled components, melt blended in a screw extruder and cast onto a cooled quench roll to form amorphous sheets. The amorphous sheets, ranging in thickness from 325 to 450 microns, were evaluated for formabillty by preheatlng the ~heet from 8 to 10 seconds to a temperature from 90 to 100C., and formlng ln a heated vacuum rormlng mold.
Mold cycle tlmes and mold temperatures varled as ~hown ln Table II.
Formabillty, or moldlng quallty, lncludlng con-formatlon to the mold cavity, the unirormlty Or the llp Or the formed tray, and the ease Or mold release were evaluated with results as shown ln Table II.
The perrormance Or the rormed tray wlt~, respect to toughness or brlttleness (l.e., durablllty) were evalu-ated after oven heating for 15 mlnutes at 200C., wlth results also as shown in Table II.
In thls durablllty evaluatlon the trays were licked wlth a flnger after such oven heatlng and coollng to room temperature and, as Table II shows, trays formed from sheets of polyethylene terephthalate blended wlth the terpolymer were "tough" and undamaged whlle trays Or sheets made using the copolymer were 80 "brlttle" they shattered at the point of impact.
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,~ " ~ p, ~ ~ p c!~
~ p, ,~ I I I 1 ~0 E~ ~) * ~ ** ~
* *
The samples were prepared from carefully drled components, melt blended in a screw extruder and cast onto a cooled quench roll to form amorphous sheets. The amorphous sheets, ranging in thickness from 325 to 450 microns, were evaluated for formabillty by preheatlng the ~heet from 8 to 10 seconds to a temperature from 90 to 100C., and formlng ln a heated vacuum rormlng mold.
Mold cycle tlmes and mold temperatures varled as ~hown ln Table II.
Formabillty, or moldlng quallty, lncludlng con-formatlon to the mold cavity, the unirormlty Or the llp Or the formed tray, and the ease Or mold release were evaluated with results as shown ln Table II.
The perrormance Or the rormed tray wlt~, respect to toughness or brlttleness (l.e., durablllty) were evalu-ated after oven heating for 15 mlnutes at 200C., wlth results also as shown in Table II.
In thls durablllty evaluatlon the trays were licked wlth a flnger after such oven heatlng and coollng to room temperature and, as Table II shows, trays formed from sheets of polyethylene terephthalate blended wlth the terpolymer were "tough" and undamaged whlle trays Or sheets made using the copolymer were 80 "brlttle" they shattered at the point of impact.
,,.. -. - .: , - , .
~6~4t~338 ~,. . . .
o ~ ~ -o ~ o o U~ ~ o ~ .
"' I V .C V I ~ ~ , C ~
~: L' 1~ ~ ~ P C~
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U~ U~ U~ U~ U~I~ I~ m ~ o .C fi ,4 ~ ,~
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. . . . .
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~ ~ ' o o o ~o ~ ~ ,~ U~ ~ ~ ~ ~ ~ ~ o o o . .; . ' .
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* *
Claims (21)
1. A composition for sheets, films, coatings or containers comprising a blend of polyethylene tere-phthalate with a polymeric additive that is mainly but not entirely based on ethylene, characterized in that the blend includes, by weight, 99 to 95% polyethylene terephthalate and 1 to 5% of a terpolymer of at least 65% ethylene with (a) at least 5% of a vinyl ester of a 1-6 carbon saturated monobasic aliphatic carboxylic acid and (b) 0.1 to 10% of acrylic and/or methacrylic acid.
2. A composition according to Claim 1 wherein there is used a vinyl ester of a 1-4 carbon acid.
3. A composition according to Claim 2 wherein the ester is vinyl acetate.
4. A composition according to Claim 1 wherein quantity of vinyl ester is at least 12%.
5. A composition according to Claim 4 wherein quantity of vinyl ester is 20-30%.
6. A composition according to Claim 1 wherein quantity of acrylic and/or methacrylic acid is at least 0.5%.
7. A composition according to Claim 6 wherein quantity of acrylic and/or methacrylic acid is up to 7%.
8. A composition according to Claim 6 wherein quantity of acrylic and/or methacrylic acid is up to 3%.
9. A composition according to Claim 1 wherein quantity of terpolymer is 3%.
10. A composition according to Claim 1 wherein the terpolymer is 72% ethylene, 27% vinyl acetate and 1%
methacrylic acid.
methacrylic acid.
11. A composition according to Claim 1 wherein the polyethylene terephthalate contains from 0.1 to 1.5%
by weight of a finely divided inert mineral solid substance.
by weight of a finely divided inert mineral solid substance.
12. A composition according to Claim 1 wherein the polyethylene terephthalate contains a nucleating agent.
13. A composition according to Claim 12 wherein the nucleating agent is selected from calcium carbonate, aluminum silicates, and talc.
14. A composition according to Claim 1 wherein the polyethylene terephthalate contains an opacifying agent.
15. A composition according to Claim 1 wherein the polyethylene terephthalate contains titanium dioxide.
16. A composition according to Claim 1 wherein the polyethylene terephthalate contains 1% talc and 1.5%
titanium dioxide.
titanium dioxide.
17. A composition according to Claim 1 wherein the inherent viscosity of the blend is from 0.70 to 0.95.
18. A shaped article formed from the composition according to Claim 9 or 10.
19. A tray formed from a sheet made from the composition according to Claim 9 or 10.
20. An article according to any of Claims 1, 9 or 10 having an inherent viscosity of from 0.65 to 0.85.
21. A container or tray for heating food up to 200°C., shaped from a composition according to any of Claims 1, 9 or 10 and having an inherent viscosity of from 0.65 to 0.85.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US39426473A | 1973-09-04 | 1973-09-04 | |
| US48882674A | 1974-08-02 | 1974-08-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1040338A true CA1040338A (en) | 1978-10-10 |
Family
ID=27014664
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA208,306A Expired CA1040338A (en) | 1973-09-04 | 1974-09-03 | Polyethylene terephthalate/terpolymer blends; films, sheets, and articles made using such blends; and method of making trays using such sheets |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5072950A (en) |
| BE (1) | BE819496A (en) |
| CA (1) | CA1040338A (en) |
| DE (1) | DE2442226A1 (en) |
| FR (1) | FR2242435B1 (en) |
| GB (1) | GB1440735A (en) |
| IT (1) | IT1030607B (en) |
| LU (1) | LU70840A1 (en) |
| NL (1) | NL7411650A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1104734A (en) * | 1977-12-30 | 1981-07-07 | Stuart C. Cohen | Unfilled thermoplastic molding compositions |
| US4322333A (en) * | 1979-11-05 | 1982-03-30 | General Electric Company | Reinforced PBT-copolyaromatic/aliphatic block copolyesters |
| JPS5985674U (en) * | 1982-11-29 | 1984-06-09 | 高千穂電気株式会社 | electric soldering iron |
| US5310787A (en) * | 1991-06-04 | 1994-05-10 | Du Pont-Mitsui Polychemicals Co., Ltd. | Polyester packaging material |
| GB9415557D0 (en) * | 1994-08-02 | 1994-09-21 | Chamberlain Vinyl Products Ltd | Shoe stiffener |
| GB2476029A (en) * | 2009-11-06 | 2011-06-15 | Pregis Rigid Packaging Ltd | Polyethylene terephthalate copolymer container manufactured using nucleating agent |
-
1974
- 1974-09-02 JP JP49099986A patent/JPS5072950A/ja active Pending
- 1974-09-03 CA CA208,306A patent/CA1040338A/en not_active Expired
- 1974-09-03 GB GB3842274A patent/GB1440735A/en not_active Expired
- 1974-09-03 BE BE148175A patent/BE819496A/en unknown
- 1974-09-03 FR FR7429897A patent/FR2242435B1/fr not_active Expired
- 1974-09-03 NL NL7411650A patent/NL7411650A/en not_active Application Discontinuation
- 1974-09-03 LU LU70840A patent/LU70840A1/xx unknown
- 1974-09-03 IT IT26893/74A patent/IT1030607B/en active
- 1974-09-04 DE DE2442226A patent/DE2442226A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| LU70840A1 (en) | 1975-06-11 |
| NL7411650A (en) | 1975-03-06 |
| JPS5072950A (en) | 1975-06-16 |
| IT1030607B (en) | 1979-04-10 |
| FR2242435A1 (en) | 1975-03-28 |
| DE2442226A1 (en) | 1975-03-06 |
| GB1440735A (en) | 1976-06-23 |
| BE819496A (en) | 1975-03-03 |
| FR2242435B1 (en) | 1978-02-17 |
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