CA2348820A1 - Modified thermoplastic composition and method of production of same - Google Patents
Modified thermoplastic composition and method of production of same Download PDFInfo
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- CA2348820A1 CA2348820A1 CA 2348820 CA2348820A CA2348820A1 CA 2348820 A1 CA2348820 A1 CA 2348820A1 CA 2348820 CA2348820 CA 2348820 CA 2348820 A CA2348820 A CA 2348820A CA 2348820 A1 CA2348820 A1 CA 2348820A1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/08—Processes
- C08G18/0895—Manufacture of polymers by continuous processes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
- C08G18/4205—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups
- C08G18/4208—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing aromatic groups
- C08G18/4211—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing aromatic groups derived from aromatic dicarboxylic acids and dialcohols
- C08G18/4213—Polycondensates having carboxylic or carbonic ester groups in the main chain containing cyclic groups containing aromatic groups derived from aromatic dicarboxylic acids and dialcohols from terephthalic acid and dialcohols
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- 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
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2101/00—Manufacture of cellular products
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2270/00—Compositions for creating interpenetrating networks
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- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
A process for creating a polymer of increased flexural modules, toughness and tensile strength, comprised of an interpenetrating network ("IPN") of a secondary polymer which is intensely dispersed within a first polymer, utilizing at least one isocyanate reacted with a catalyst. The composition has improved mechanical and processing properties rendering it useful as a moldable resin.
Description
Resend 5-25-0~; 4:28PM;Furman & Kallio R9a ;+~ 306 359 6956 # 4/ 25 942-Q2~OS
M4D1FIED THERMO~X.AST1C COMPOSITION AND IVXET~OD OF C
v PItUbUCTION OF SAME
T.he present discovery relates to a thermoplastic consisting of an interpenetrating network ("IpN") which exhibits high melt strengths.
BAC~CItOTJNb OF TTI~INVENTXUN:
Production of polyetl~ylone terephthalatc ("PBT") consisting of an interpenetrating network ("IPN"), which exhibits high melt strengths and other favorable characteristics, is known in the art. Au IPN is comprised of a secondary polymer which is intensely dispersed withiu~ a first incompatible polymer. In U.S. Patent No. 4,409,167 (Kolouch et a1), a process is described of coupling an incrnnpatible polymer with PET to produce a PST blend resin in the presence of isocyaaatc with a much increased melt strength, however, this process does not result in the formation of an interpenetrating network.
It is also well understood that there arc Limitations pertaining to polymer, and specifically PET, processabifity which tcrnd to limit the thiclaness of finished products, such as sheet in amorphous phase, this being due to the crystallization which occurs in heavy wall materials, rendering the product brittle aaxd non formable in secondary processes.
Polystyrene, when used as a foam, has a very broad process window of typically 50°F, whereas the z~anges in which crystalline or semi-crystalline polyesters foam are very narrow, as described in US Pat. 5,2$8,764. It would be desirable to provide a PET resin that overcomes these narrow processing parameters. r ,.
i.
Theca have been many attempts to address this melt strength problem by means of branching and/or thermal zx~elt addition of dissimilar polymers such as nylon, polycarbonate, polyethylene, etc., as described For example in U.S. Patent Nos. 4,9$1,631 Resend 5-25-0~; 4:28PM;Furman & Kallio R9a ;+~ 306 359 6956 # 5/ 26 942-02-45 f (Cheung et al), 5,288,764 (Rotter et al), and 5,696,176 (Khemani et al).
Continued difficulties persist in this prior art insofar as resolving tlxe need to expand the process a window while at the same time maintaining the thermal stability of products produced from such compositions and processes. This is especially true in cases of Iow intrinsic viscosity ("1V") PET, such as recycled bottle stock, which has repeated heat lxistories that have lowered the 1V to below acceptable levels. Virgin PET with intrinsic viscosities below 0.8 also must be enhanced by addition of expensive branching and nucleating agents in order to produce acceptable foam or other lightweight products. Such branching agents still fail to sufficiently expand the temperariue range needed for maximum processability of PET, and thus limit the applications in which these modified PETS can be used.
Previous endeavors which have been made to solve the problem relating to the abrupt tran,sitian between the melt crystalliuxe te,nperahcre window and the lowez temperature required to maintain die melt strength have had limited success, such as U.S.
Patent Nos.
5,000,991 and 5,134,02$ (Hyashi et al), which attempt to address some of the problems through the use of branching agents such as PMDA. This approach o$en produces levels of unreacted PMDA or other residue heat stabilizers that exceed minimum health requirements and are extremely detrimental in the case of Toad applications such as vacuum formed food trays.
tJ.S. Patent No. 5,364,908 (~ishi at al) demonstrates a means with which to produce a high: melt compound based on pET by prereacting a number of rrinyls, polyesters, pofymides, polyethcrs and polyuz~etk~anes, and melt blending them in the presence of isocyanates or epoxy resins in the presence of a diisacyanate. This process requires a separate step to create a polymer, wluch is used to compatabilize dissimilar polymers, r ,.
and does not do wa in situ in order to form an IPN. This process describes a means with which to compat-abilize dissimilar polymers by first creating a dispersant pre-polymer that has functionality snn, lar to at least one of the primary resins. It is also necessary to pre-form a compatabilizer and thereafter melt blend it into the dissimilar polymers. No Resend 5-25-0~; 4:28PM;Furman & Kallio R9a ;+t 306 359 6956 # 6/ 26 a mention is made in the disclosures of that patent regarding the production of low-density materials. Furthermore, the compositions thus produced are used to secondarily compatabilize dissimilar polymers in the presence of diisocyanates while melt blending.
This requires a complete secondary costly process and further does not address the need to limit the percentages of low thermal stable polymers. This process fails to address the much desired need for an impact modified f~T which both has the thermal stability and can be dozxe in situ in a single step. further, this prior art teaches nothing of the needs pertaining to impact improvements as relate to lighter der~ity products. This leads to a limited usage and application such as extn~ded products whore shape and form must be maintained until cooled.
F
SlJlh?IyIAnY OF INVEN'I'K~N:
The present invention is directed at the production, of polymers, including PET, having a minuscule 1PN of a secondary polymer which is intensely dispersed within said first incompatible polymer, utilizing at least one isocyanate reacted with a catalyst, which results in increased melt strength, impact resistance, flexural modules, tensile strength and crystallization rate. The composition thus produced has greater stiffness and 2U resistance to yield at elevated temperatures which renders it especially useful for foamed articles that require rigidity and toughness, such as constriction foam board, food packaging applications end wood like replacement. 'phc thermoplastic PET
compound produced by means of the present invention also exhibits the much sought after characteristics required for solid farms such as injection molding, extruded solid products, blow molding, and the like.
I:
i=
r In addition to this modified ther<n6plastic product, the process for producing same is disclosed. The process provides a method of greatly lowering the percentage to weight of the lower thermally stable secondary polymer in the IPN which is needed to impart sufficient izzxpact strength and other properties to the first polymer. The present invention ;_ Resend 5-25-0~; 4:28PM;Fu~man & Kallio R9a ;+~ 306 359 6956 # 7/ 26 a also reduces or eliminates the need for costly branching agents in order to obtain the dasired mechanical and processing properties. The process comprises creatizzg a thermoplastic composition by dy"amic malt blending of the following components at a melt temperature: a first polymer; a secondary polymer; at least one catalyst;
and at least one isocynata or epoxy compound.
Also disclosed is a single phase process for producing a compound based on polyethylene terephthalate ("PET") and blends of polyethylene terephthalate, and aliphatic and aromatic polyolcfins, polymerised with organic diisocyanatas (whether aromatic, aliphatic, or cycloaliphatic) or epoxy compounds, in the presence of a catalyst or catalysts, which results in the creation of an interpenetrating network (IP1V) structure.
The resulting polymer composition exhibits highly increased melt, impact, tensile, and flexural strengths, fhe subsequent polymers of this discovery facilitate the manufacture of fine closed cola foams having marked improvements in low temperature grad general flexural strength. Polymers produced by the present invention fiuther exhibit izxxprovements in rates of crystallisation, thus enhancing procassability in tha amorphous phase for applications such as therxxaoformed article where secondary processing is employed. Polymer compounds of the present invention further show improved melt strength, and are therefore capably of baing axuded into thick sheet, profiles, pre-forms, and injection molded or blow molded articles. Thermoformed articles from compounds produced through the present discovery exhibit extremely high draw ratios at irACreased crystallisation levels.
More specifically, the compound exhibits unusual and beneficial characteristics that facilitate the creation of both axtremely law density foamed articles and high density =-solid polymers, both of these being characterized by increased impact, flex, and melt a strangths as well as other much sought after advantages. The IPN is formed with E
relatively tow levels (often 10 weight pyrcant or lass) of secondary polymers, created in situ in a single step process which forans co-continuous structures within the main first polymer. Tha advantage of creating this IPN polymer in situ, while foaming, is that it r.
Resend 5-25-0~; 4:28PM;Furman R Kallio R9a ;+~ 306 359 6956 # 8/ 26 i, results in the production of a micron size cell structure capable of forming extremely low-density material with very improved mechanical properties, capable of utilizing a n n broad temperature processing wind4w. Fo~,tns that arc produced with the present invention facilitate a marked reduction in gas requirements for foaming, and further 5 contribute to a reduction in the use of expensive and detrimental additives such as branching agents normally required.
DETAILED DESCRIPTION OF THE PREFI~I~ItED EMBODIMENTS:
As outlined in general above, the present invention is a modified poiymez~
product and a process for producing same. Tht modified polymer product has desirable processing qualities and paramete~cs as well as broad uses. It is particularly contemplated that thr;
present invention will have utility in the production of a modified polyethylene tercphthalate (fET), wherein PET would be used as the first polymer in the product. It will be wnderstood, howwer, that the process of the present invention could also be practiced on other first polymers axed any other such first polymer is also contemplated within the scope of the present invention.
It has been the practice xr~ the prior art to impart improved mechanical properties to PET
by large additions of either a dissimilar polymer or a coxnpatabilizer to produce the desired properties in the end composite, whether diisocyanates were employed or not.
The lower melt characteristics of the modifying polymer taught in the prior art have greatly inhibited applications where high temperature thermal stability in finished products is mandated, such as food trays for oven-bakeable applications, under-hood applications in automotive engineering, or for high temperature insulation foams. This discovery enables the production of a modified PET which is capable of achieving the higher service temperature applications, Without the need for large amounts of expensive impact modifying polymers such as SEBS or thermally unstable impact modifying secondary potym~rs, previously needed to mechanically improve the base PET.
!~
Resend 5-25-0~; 4:28PM;Furman & Kallio Rga ;+~ 306 359 6956 # 9/ 26 l~Tovc1 thermolalastic comflosatian: E
T.he modified thermoplastic composition of the present invention is created from the blending of a melted first polymer together with a secondary polymer in the presence of a catalyst, together with at least one isocyanate or epoxy compound. Generally speaking it is intended that the first polyzxxer which is modified using this process, resulting in the creation of interpenetrating networks therein, is polyethylene tcrcphthalate.
Xt will however be understood that it might be obvious to one skilled in the art to alter or modify t this composition by using a different first polymer, and such other polymers and attendant obvious alterations in the process or composition are contexxxplated within the scope of the present invention. The first polymer could also be any crystalline polymer or modified .PST as described in "Modern Plastics, Encyclopedia 9$". The precise method of production of this modified tliermopIastic composition is outlined in further detail below.
It is contemplated that the P~'l' or other first polymer would comprise between 60 to 99 percent by weight of the total components used in the creation of the thermoplastic composition, and that any amount of first polymer in this range is contemplated within the scope of the present invention.
Whether the first polymer is PET or otherwise, it is intended that the raw PET
resin or first polymer used in the creation of the composition of the present invention could either be virgin thermoplastic material, or alternatively could come from scrap or recycled sources. It will be understood that the process and composition of the present invention are particularly useful in the production of the themaoplastic composition of the; present invention using scrap or recycled PET since the process of the present invention will allow for the strengthening of the first polymer which might otherwise be degraded from previous heating or manipulation. 1t will be understood that the use of any grade of 1~ET
resin or other first polymer is contemplated within the scope of the invention as claimed.
E.
r Resend 5-25-0~; 4:28PM;Furman & Kallio R9a ;+~ 306 359 6956 # ~0/ 26 Where recycled. or scrap polymers arc used, it will be understood that there might be residues of barrier-coatings, such as polyatnidcs or tlorocarbons, present iua same, which E
will not effect the process or its output detrimentally.
By using minor amounts of secondary polymers with lower melt temperatures, the product yielded retains the much desired thermal properties of the crystalline PET or other similar first polymer. Practiciszg of this invention produces thermoplastics, and specifically PET, that can retain their lii,gh thermal stability. It is contemplated that the quantity of secondary polymer would be in the range of 1 to 40 weight % of the fiirst polymer present in the compositivzr. 1t will be understood that any secondary polymer inclusion within this range is contemplated within the scope of the present i.zwe"tion.
The secondary polymer disclosed in the e~cample outlined below is polyethylene, but it will be understood that other polycarbomidcs or other polymers might also be used as the secondary polymer in the composition of the product of the present invention and that such changes will also be contemplated within the scope of the present invention.
Without limiting the senerality of the foregoing, other specific secondary polymers which are contemplated arc any aliphatic and aromatic polyolefins, or polyamides or E'VA.
copolymers, and specifically polyethylene, ethylene vinyl acetate or polypropylene.
Dependent upon the desired end result, the first polymer and secondary polymer used might either be compatible or incompatible, also known as similar or dissirnilar, for blending purposes, which will yield different results from the blending process. It will be understood that axzy combination of compatible or incompafible first and secondary polymers is contemplated within the scope of the present irzveution.
The product of the present invention produces foams at extremely high-elevated temperatures, often in the range of490°F to 520°F, which all prior art fails tQ accomplish.
hTence extremely low-density foamed products with high melt strengths and greatly increased impact rcsista:nce can be produced, thereby allowing the polymeric composition of the present in ention to be formed into previously impossible configurations. Much Resend 5-25-Oi; 4:28PM;Furman & Kallic R9a ;+7 306 359 6956 # »/ 26 desired higher rates of throughput can be attained as well, due to eliminating the requirement of extensive cool down, as is the case in tandem line foaming apparatus used t to make foam sheet for packaging.
S The catalyst which is used might eith.ex be added as a separate ingredient, or in some cases might actually be compounded into the seconc~ry polymer being used in the composition Qf the product of the present invention. The catalyst, it is contemplated, would generally speaking be used in the axxaount of 0-001 to 5.0 weight % of the first polymer, depending on the type or combination of catalysts being used and the desired results.
Also, the catalyst component znay contain a degree of chemical foaming agerxt and disper5ant, with which to regulate tha rate and degree with which the IPNs are formed.
Various types of chemical foaming agents and dispersants could be used and it will be 35 understood that all such agents and dispersants are coxxtez~apiated within the scope of the present invention. Non polar hydrocarbon .foaming agents may be used, separately or in cambinatiox~ with chemical blowing agents that enhance tha dispersion and structure of the IPNs such as 5-Phenyltetra.zQle. The present invention answers the diff',culties encountered in the prior art in production of foams over a wide temperatuxe range.
Foams produced through this invention also exhibit melt strengths and surface smoothness uncharacteristic of prior art. Without limiting the generality of the types of hydrocarbon foaming agents which could be used, it is contemplated that they might be selected from the group of: isopentanc, cyclopentane, carbon dioxide, n-pentane, nitrogen, butane, isohexane, heptane and chlorodifloro-methane.
1t will be obvious to one skilled in the art various types of catalysts which could be used in the process and reaction of the present invention, and it is intended that all such catalysts are contemplated within the scope of the claims herein. Without limitixAg the generality of the foregoing, however, it is contemplated that the catalysts might be one or more nucleating agent, such as polynethyl siloxane or selections iiom the group Resend 5-25-0~; 4:28PM;Furman & Kallio R9a ;+i 306 359 6956 # ~2/ 26 including talc, calcium fluoride, sodium phenylphosphinate, aluminum oxide, titanium dioxide, fnely divided polytetrahuoroethylene, tetlon, or pyromcllitic dianhydride (PMDA), sulfuric acid, ron oxide or any base earth metal groups,.and/or might be one or more catalysts selected ifrom the following: dibutyltin dilaurate, maleate, precursors for phenolic resin, urea, melamine, dioctyltin dilaurate, sulphuric acid, sodium acetate, zinc chloride, carbomide, 5-phcnyltctrazole, tart-butyl peroxy 2-ethylhexyl carbonate, tart-butyl peroxy-3,5,5-trimcthylhcxanoato, 2,5-.Uiznethyl-2,5-di(tert-butylperoxy)hexane, tart-butyl peroxyber~coate. The catalysts might be one or more of these types of cor,~.pounds.
to While the isocyanate discussed above is methylenediphenylene diisocyanatc ("MDi"), it will be understood that any number of other isocyanates or derivatives of isocyanates, such as diisocyanates or triisQcyanates, could be used and it will be understood that all such isocya,nates and derivatives thereof are contemplated within the scope of the claimed invention. Without tirniting the generality of the foregoing, it Is contemplated that some of tlxe isQCyanates which might be used are 4,4'- phenylmathari~ diisocyanate (MI7n, polyn~ethylene polyphcnyl, polyisocyanate (f.A,p~.
The compositions made possible by the present disclosure arc a result of dynamic curing of the isocyanate in th.e presence of a catalyst which both serves to transitionally cure the carries resin while polymerizing the isocyanatc, thus forming minute interpenetrating networks which act as membranes to any foam cells which are formed in situ in the PET
or other first polyzz~ez~ .resin. It is this aspect, namely the formation of the interpenetrating network, as has been discovered, that causes the extremely fme dispersioxt az~d zetention of closed foam cells, even at extremely high die exit temperatures, e.g.
500°F. This is done without the need to branch the PET as described in much of the prior art.
The 1PN
a composition formed also produces solid polymers with much improved mechanical properties without the loading of large amounts of modif~ring secondary polymers as the prior arts teach. This makes the properties of tl~e composition thus produced far more m Resend 5-25-Ot; 4:28PM;Furman & Kallio R9a ;+~ 306 359 6958 # 13/ 26 resemble those of the parent PET than the trade-off properties which are experienced when employing the prior art.
C
Epoxy compounds could also be employed in the production of the modified PET
or first 5 polymer of the present invention. Various epoxy compounds could he used and it will be understood that all such epoxy compounds are contemplated within the scope of the prevent invention, but without limitang the generality of the foregoing it is specifically thought that the epoxy compounds might include phenols, bisplienols, aromatic epoxy resin and cycloaliphatic epoxy resin. As well, it will be understood tlaat more than one 10 isocyanate and/or epoxy compound might be used in a blend. It is contemplated that isocyanates ar epoxy compounds will be pt'eseot in the amount of .over 0.01 weight percent of the first polymer used in the campvsition- It will be understood that variations in the components the secondary polymer, the eatfi,lyst or catalysts and the isocyanatcs ar epoxy compotuads, as dictated by the application to which the compound is to be applied, are contczxtplated within the scope of the present invention as well.
,An oxygen barrier such as vinyl siloxane could also be added to the product of the present invention and it will be understood that variations in the oxygen barrier employed are also contemplated within the scope of the present invention. Similarly various heat stabilizers could be employed, which it will also be understood are contemplated within the scope ofthe presex~.t invention.
The method of blending employed in the production of the modified thermoplastic composition of the present invention can have a controlled and preferable effect on the final product as well. if an aggressive or dynamic blending process is employed a mart homogenous product will be yielded, since the dynamic blending will cause the size of the particle dispersion in the IfNs created to diminish. A hpmagenous product such as this with a lower dispersion will yield a higher tensile strength thennoplastie composition. Altcmativcly, it may also in certain circumstances be desiured to produce a thermoplastic composition with a lower tensile characteristic or the like, in which case a Resend 5-25-0~; 4:28PM;Fu~man 8~ Kal~io Rga ;+~ 306 359 6956 # 14/ 26 ii nzpre passive blending method z~cti~ht be employed. It will be understood that both types of thermoplastic composition, namely those produced by dynamic or non-dynann.i.c blending, as well as the process of the present invention employing either dynamic or non-dynamic blending, are contemplated within the scope of the present invention.
The product, a ra.vdified thermoplastic composition of a durst primary polymer, of the present invention exhibits better attributes than a standaz~ sample of said first polymer.
For example, where the first polymer is PET the present invention yields a product with a markedly higher intrinsic viscosity than a standard PET sheet. The following graph shows the intrinsic viscosity of a sheet of modified i'ET (marked as Davilon thereon) of the present invention in comparison to a standard PET sheet:
Intrinsic Viscosity 7.4 --.
1.2 _..
... . ..._ ....
0 ..-_...
, -- . O Intrinsic Vscosity D (tlUg) . ...
. ...._._ .
o ... __.
a . f~
a o n Devilon $Iandrd PE'T t l Sheet St,eet 1S Similarly, the product of the present invention also exhibits other better material properties than a standard sample of a first polymer being PET or otherwise.
For i~
Il A
Resend 5-25-0~; 4:28PM;Furman & Kallio Rga ;+~ 306 359 6956 # ~5/ 26 )42-02-OS
lz example, the thermoplastic composition of the present invention will exhibit a better co efficient of thermal expansion, greater tear strength, increased flexural modules, improved elongation or tensile strength characteristics and/or Ga,mder impact performance than standard samples of the first polymer being modifed in accordance with the present invention.
Method of prod coon of thermoplastic composition:
The discussion of the product, thermoplastic composition, above it will be understood is equally applicable to the details of the process ofproduction of same outlined below. As outlined in the claims hcr~;of, the modified thermoplastic composition produced by tlxe process of the present invention is produced by tht dynamic melt blending of the various components. The most preferred zzxethod of producing the compounds is by way of melt blending in a thermoplastic extruder. Either a single or twin screw extruder could be used. Alternatively, an application unit such as a,n injection molding unit could also be used to perform the melt blending operation to produce the modified PET of the present invention. It will be understood that any other type of an apparatus which can be used to melt blend the composition of the present invention is also contemplated within the scope hereof.
One preferred embodiment of the preaent invention is the utilization of a low IV (U-GS to U.75) PET as the first polymer in combination with dibutyltin dilaurate together with linear low-donsity polyethylene and MDI. As outlined in detail herein, these components might be v<~,ri~;d without departing from the scope of the claimed iz~veution, In one exaxnple, a component batch of 97.17% by weight PET, 2% by weight linear low-density polyethylene, 0.03% DBTL (catalyst) and 0.8% MDI (methylenediphenyle"e diisocyanate) were processed at 530 degrees Fahrenheit in a barrier single screw extruder (30:1 LxD), and at the completion of the dynamic melt blending the dye exit temperature was 505 degrees Fahrenheit.
Resend 5-25-Oi; 4:~gPM;Furman & Kallio R9a ;+7 306 359 6956 # ~6~ 26 Preferably, the PET and catalyst, together with the polymer used to form the structure, are introduced at the feed throat of the extruder, with the MDt injected at a port in the extruder barrel after melt blending has occurred, although in practice, the introduction of alt components at the feed tb~z~oat has proven quite satisfactory in producing the compounds described herein. The PET resin and compounds can be preblendcd and or dry blended provided the catalyst's sensitivity to heat is not an issue.
Alternatively, such catalyst rnay be added separately at tlac feed throat.
The catalyst cov~ld be added or present at a level of 0.401 to 10.0 weight percent, based on the weight of the first polymer.
Weight percentages of catalyst Mbil in the production of low-density foam may be irt the area of 0.1 to 3.0 weight percentage of the first polymer, and, in the case of high-density non.-foamad compounds, as high as f weight percent. The blended materials are heated during extrusion to a temperature in the range of 4$0°F to 560°F, or at a minimum to the melt phase of the higher melt first polymer being incorporated, provided it does not exceed the temperature where the lower melt secondary polymer would deteriorate, with sufficient residenc~r time as to allow the diisocyanate to be extensively dispersed aztd cured so as to create the IPN sub stzucture. The dynamic melt blending of the product 24 could take place at any melt teanperature which is sufficient to ensure at least two phases have 3-dimensional spatial continuity resulting from the dynamic ~uriztg in the presence of the catalyst. Tandem extrusion may be used where optimum characteristics aid control of the finished composition or foam is preferred.
ZS A. .hydrocarbon gas might be added during melt-blending. other additives which might be added during the melt bleztding include one or more of antioxidants, stabilizers, dyes, flame-retardants, c;xtenders, UV stabilizers and other processing aids. Where heat stabilizers are added to the process or product of the present invention, the heat stabilizers) might be compounded into an IrVA carrier resin or vinyl based carrier resin 30 or alternatively added directly during processing. The carrier resin might be a polyolefirt t=
p Resend 5-25-0~; 4:28PM;Furman & Kallio R9a ;+~ 306 359 6956 ~ ~7/ ~6 9az-oz-os which comprises from 2 to 6 carbon aton,5. Similarly, the catalyst might be added directly to the composition or process, or might be compounded into an elastomer for addition. Specifically, the catalyst might optionally be compounded into a CPE
p~lyalt~.
Vinyl siloxane might also be added during the blending process, in a sufficient amount to form a surface oxygen barrier. Alternatively the PET conxposike might be coated with an oxygen inhibiting barrier coat compaCible with the PET resin upon exiting the extruder or other blending unit.
lU
The blended thermoplastic could be rapidly cooled upon exiting the blending vessel. it could be cooled in either sheet or pellet form, amongst others, dependent upon the secondary manufaehuing processing requirements. Where foaming agents had teen added in or shifted to a gaseous state during the blending, rapid cooling might optazz~ally trap the foaming agent within the thermoplastic in a liquid phase such that in secondary manufacturing upon rebeating of the PET product, the foaming agent would shift back to its gaseous state and the need for separate addition of foaming agents in secondary manufacturing could be lessened.
The product of any variation of the process of the present invention outlined herein, is contemplated within the scope of the claimed invention as well, Thus it can be seen that the invention accomplishes all of its stated objectives. The foregoing is considered as illustrative only of the principles of the invention. Further, since nuxz~orQus changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.
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M4D1FIED THERMO~X.AST1C COMPOSITION AND IVXET~OD OF C
v PItUbUCTION OF SAME
T.he present discovery relates to a thermoplastic consisting of an interpenetrating network ("IpN") which exhibits high melt strengths.
BAC~CItOTJNb OF TTI~INVENTXUN:
Production of polyetl~ylone terephthalatc ("PBT") consisting of an interpenetrating network ("IPN"), which exhibits high melt strengths and other favorable characteristics, is known in the art. Au IPN is comprised of a secondary polymer which is intensely dispersed withiu~ a first incompatible polymer. In U.S. Patent No. 4,409,167 (Kolouch et a1), a process is described of coupling an incrnnpatible polymer with PET to produce a PST blend resin in the presence of isocyaaatc with a much increased melt strength, however, this process does not result in the formation of an interpenetrating network.
It is also well understood that there arc Limitations pertaining to polymer, and specifically PET, processabifity which tcrnd to limit the thiclaness of finished products, such as sheet in amorphous phase, this being due to the crystallization which occurs in heavy wall materials, rendering the product brittle aaxd non formable in secondary processes.
Polystyrene, when used as a foam, has a very broad process window of typically 50°F, whereas the z~anges in which crystalline or semi-crystalline polyesters foam are very narrow, as described in US Pat. 5,2$8,764. It would be desirable to provide a PET resin that overcomes these narrow processing parameters. r ,.
i.
Theca have been many attempts to address this melt strength problem by means of branching and/or thermal zx~elt addition of dissimilar polymers such as nylon, polycarbonate, polyethylene, etc., as described For example in U.S. Patent Nos. 4,9$1,631 Resend 5-25-0~; 4:28PM;Furman & Kallio R9a ;+~ 306 359 6956 # 5/ 26 942-02-45 f (Cheung et al), 5,288,764 (Rotter et al), and 5,696,176 (Khemani et al).
Continued difficulties persist in this prior art insofar as resolving tlxe need to expand the process a window while at the same time maintaining the thermal stability of products produced from such compositions and processes. This is especially true in cases of Iow intrinsic viscosity ("1V") PET, such as recycled bottle stock, which has repeated heat lxistories that have lowered the 1V to below acceptable levels. Virgin PET with intrinsic viscosities below 0.8 also must be enhanced by addition of expensive branching and nucleating agents in order to produce acceptable foam or other lightweight products. Such branching agents still fail to sufficiently expand the temperariue range needed for maximum processability of PET, and thus limit the applications in which these modified PETS can be used.
Previous endeavors which have been made to solve the problem relating to the abrupt tran,sitian between the melt crystalliuxe te,nperahcre window and the lowez temperature required to maintain die melt strength have had limited success, such as U.S.
Patent Nos.
5,000,991 and 5,134,02$ (Hyashi et al), which attempt to address some of the problems through the use of branching agents such as PMDA. This approach o$en produces levels of unreacted PMDA or other residue heat stabilizers that exceed minimum health requirements and are extremely detrimental in the case of Toad applications such as vacuum formed food trays.
tJ.S. Patent No. 5,364,908 (~ishi at al) demonstrates a means with which to produce a high: melt compound based on pET by prereacting a number of rrinyls, polyesters, pofymides, polyethcrs and polyuz~etk~anes, and melt blending them in the presence of isocyanates or epoxy resins in the presence of a diisacyanate. This process requires a separate step to create a polymer, wluch is used to compatabilize dissimilar polymers, r ,.
and does not do wa in situ in order to form an IPN. This process describes a means with which to compat-abilize dissimilar polymers by first creating a dispersant pre-polymer that has functionality snn, lar to at least one of the primary resins. It is also necessary to pre-form a compatabilizer and thereafter melt blend it into the dissimilar polymers. No Resend 5-25-0~; 4:28PM;Furman & Kallio R9a ;+t 306 359 6956 # 6/ 26 a mention is made in the disclosures of that patent regarding the production of low-density materials. Furthermore, the compositions thus produced are used to secondarily compatabilize dissimilar polymers in the presence of diisocyanates while melt blending.
This requires a complete secondary costly process and further does not address the need to limit the percentages of low thermal stable polymers. This process fails to address the much desired need for an impact modified f~T which both has the thermal stability and can be dozxe in situ in a single step. further, this prior art teaches nothing of the needs pertaining to impact improvements as relate to lighter der~ity products. This leads to a limited usage and application such as extn~ded products whore shape and form must be maintained until cooled.
F
SlJlh?IyIAnY OF INVEN'I'K~N:
The present invention is directed at the production, of polymers, including PET, having a minuscule 1PN of a secondary polymer which is intensely dispersed within said first incompatible polymer, utilizing at least one isocyanate reacted with a catalyst, which results in increased melt strength, impact resistance, flexural modules, tensile strength and crystallization rate. The composition thus produced has greater stiffness and 2U resistance to yield at elevated temperatures which renders it especially useful for foamed articles that require rigidity and toughness, such as constriction foam board, food packaging applications end wood like replacement. 'phc thermoplastic PET
compound produced by means of the present invention also exhibits the much sought after characteristics required for solid farms such as injection molding, extruded solid products, blow molding, and the like.
I:
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r In addition to this modified ther<n6plastic product, the process for producing same is disclosed. The process provides a method of greatly lowering the percentage to weight of the lower thermally stable secondary polymer in the IPN which is needed to impart sufficient izzxpact strength and other properties to the first polymer. The present invention ;_ Resend 5-25-0~; 4:28PM;Fu~man & Kallio R9a ;+~ 306 359 6956 # 7/ 26 a also reduces or eliminates the need for costly branching agents in order to obtain the dasired mechanical and processing properties. The process comprises creatizzg a thermoplastic composition by dy"amic malt blending of the following components at a melt temperature: a first polymer; a secondary polymer; at least one catalyst;
and at least one isocynata or epoxy compound.
Also disclosed is a single phase process for producing a compound based on polyethylene terephthalate ("PET") and blends of polyethylene terephthalate, and aliphatic and aromatic polyolcfins, polymerised with organic diisocyanatas (whether aromatic, aliphatic, or cycloaliphatic) or epoxy compounds, in the presence of a catalyst or catalysts, which results in the creation of an interpenetrating network (IP1V) structure.
The resulting polymer composition exhibits highly increased melt, impact, tensile, and flexural strengths, fhe subsequent polymers of this discovery facilitate the manufacture of fine closed cola foams having marked improvements in low temperature grad general flexural strength. Polymers produced by the present invention fiuther exhibit izxxprovements in rates of crystallisation, thus enhancing procassability in tha amorphous phase for applications such as therxxaoformed article where secondary processing is employed. Polymer compounds of the present invention further show improved melt strength, and are therefore capably of baing axuded into thick sheet, profiles, pre-forms, and injection molded or blow molded articles. Thermoformed articles from compounds produced through the present discovery exhibit extremely high draw ratios at irACreased crystallisation levels.
More specifically, the compound exhibits unusual and beneficial characteristics that facilitate the creation of both axtremely law density foamed articles and high density =-solid polymers, both of these being characterized by increased impact, flex, and melt a strangths as well as other much sought after advantages. The IPN is formed with E
relatively tow levels (often 10 weight pyrcant or lass) of secondary polymers, created in situ in a single step process which forans co-continuous structures within the main first polymer. Tha advantage of creating this IPN polymer in situ, while foaming, is that it r.
Resend 5-25-0~; 4:28PM;Furman R Kallio R9a ;+~ 306 359 6956 # 8/ 26 i, results in the production of a micron size cell structure capable of forming extremely low-density material with very improved mechanical properties, capable of utilizing a n n broad temperature processing wind4w. Fo~,tns that arc produced with the present invention facilitate a marked reduction in gas requirements for foaming, and further 5 contribute to a reduction in the use of expensive and detrimental additives such as branching agents normally required.
DETAILED DESCRIPTION OF THE PREFI~I~ItED EMBODIMENTS:
As outlined in general above, the present invention is a modified poiymez~
product and a process for producing same. Tht modified polymer product has desirable processing qualities and paramete~cs as well as broad uses. It is particularly contemplated that thr;
present invention will have utility in the production of a modified polyethylene tercphthalate (fET), wherein PET would be used as the first polymer in the product. It will be wnderstood, howwer, that the process of the present invention could also be practiced on other first polymers axed any other such first polymer is also contemplated within the scope of the present invention.
It has been the practice xr~ the prior art to impart improved mechanical properties to PET
by large additions of either a dissimilar polymer or a coxnpatabilizer to produce the desired properties in the end composite, whether diisocyanates were employed or not.
The lower melt characteristics of the modifying polymer taught in the prior art have greatly inhibited applications where high temperature thermal stability in finished products is mandated, such as food trays for oven-bakeable applications, under-hood applications in automotive engineering, or for high temperature insulation foams. This discovery enables the production of a modified PET which is capable of achieving the higher service temperature applications, Without the need for large amounts of expensive impact modifying polymers such as SEBS or thermally unstable impact modifying secondary potym~rs, previously needed to mechanically improve the base PET.
!~
Resend 5-25-0~; 4:28PM;Furman & Kallio Rga ;+~ 306 359 6956 # 9/ 26 l~Tovc1 thermolalastic comflosatian: E
T.he modified thermoplastic composition of the present invention is created from the blending of a melted first polymer together with a secondary polymer in the presence of a catalyst, together with at least one isocyanate or epoxy compound. Generally speaking it is intended that the first polyzxxer which is modified using this process, resulting in the creation of interpenetrating networks therein, is polyethylene tcrcphthalate.
Xt will however be understood that it might be obvious to one skilled in the art to alter or modify t this composition by using a different first polymer, and such other polymers and attendant obvious alterations in the process or composition are contexxxplated within the scope of the present invention. The first polymer could also be any crystalline polymer or modified .PST as described in "Modern Plastics, Encyclopedia 9$". The precise method of production of this modified tliermopIastic composition is outlined in further detail below.
It is contemplated that the P~'l' or other first polymer would comprise between 60 to 99 percent by weight of the total components used in the creation of the thermoplastic composition, and that any amount of first polymer in this range is contemplated within the scope of the present invention.
Whether the first polymer is PET or otherwise, it is intended that the raw PET
resin or first polymer used in the creation of the composition of the present invention could either be virgin thermoplastic material, or alternatively could come from scrap or recycled sources. It will be understood that the process and composition of the present invention are particularly useful in the production of the themaoplastic composition of the; present invention using scrap or recycled PET since the process of the present invention will allow for the strengthening of the first polymer which might otherwise be degraded from previous heating or manipulation. 1t will be understood that the use of any grade of 1~ET
resin or other first polymer is contemplated within the scope of the invention as claimed.
E.
r Resend 5-25-0~; 4:28PM;Furman & Kallio R9a ;+~ 306 359 6956 # ~0/ 26 Where recycled. or scrap polymers arc used, it will be understood that there might be residues of barrier-coatings, such as polyatnidcs or tlorocarbons, present iua same, which E
will not effect the process or its output detrimentally.
By using minor amounts of secondary polymers with lower melt temperatures, the product yielded retains the much desired thermal properties of the crystalline PET or other similar first polymer. Practiciszg of this invention produces thermoplastics, and specifically PET, that can retain their lii,gh thermal stability. It is contemplated that the quantity of secondary polymer would be in the range of 1 to 40 weight % of the fiirst polymer present in the compositivzr. 1t will be understood that any secondary polymer inclusion within this range is contemplated within the scope of the present i.zwe"tion.
The secondary polymer disclosed in the e~cample outlined below is polyethylene, but it will be understood that other polycarbomidcs or other polymers might also be used as the secondary polymer in the composition of the product of the present invention and that such changes will also be contemplated within the scope of the present invention.
Without limiting the senerality of the foregoing, other specific secondary polymers which are contemplated arc any aliphatic and aromatic polyolefins, or polyamides or E'VA.
copolymers, and specifically polyethylene, ethylene vinyl acetate or polypropylene.
Dependent upon the desired end result, the first polymer and secondary polymer used might either be compatible or incompatible, also known as similar or dissirnilar, for blending purposes, which will yield different results from the blending process. It will be understood that axzy combination of compatible or incompafible first and secondary polymers is contemplated within the scope of the present irzveution.
The product of the present invention produces foams at extremely high-elevated temperatures, often in the range of490°F to 520°F, which all prior art fails tQ accomplish.
hTence extremely low-density foamed products with high melt strengths and greatly increased impact rcsista:nce can be produced, thereby allowing the polymeric composition of the present in ention to be formed into previously impossible configurations. Much Resend 5-25-Oi; 4:28PM;Furman & Kallic R9a ;+7 306 359 6956 # »/ 26 desired higher rates of throughput can be attained as well, due to eliminating the requirement of extensive cool down, as is the case in tandem line foaming apparatus used t to make foam sheet for packaging.
S The catalyst which is used might eith.ex be added as a separate ingredient, or in some cases might actually be compounded into the seconc~ry polymer being used in the composition Qf the product of the present invention. The catalyst, it is contemplated, would generally speaking be used in the axxaount of 0-001 to 5.0 weight % of the first polymer, depending on the type or combination of catalysts being used and the desired results.
Also, the catalyst component znay contain a degree of chemical foaming agerxt and disper5ant, with which to regulate tha rate and degree with which the IPNs are formed.
Various types of chemical foaming agents and dispersants could be used and it will be 35 understood that all such agents and dispersants are coxxtez~apiated within the scope of the present invention. Non polar hydrocarbon .foaming agents may be used, separately or in cambinatiox~ with chemical blowing agents that enhance tha dispersion and structure of the IPNs such as 5-Phenyltetra.zQle. The present invention answers the diff',culties encountered in the prior art in production of foams over a wide temperatuxe range.
Foams produced through this invention also exhibit melt strengths and surface smoothness uncharacteristic of prior art. Without limiting the generality of the types of hydrocarbon foaming agents which could be used, it is contemplated that they might be selected from the group of: isopentanc, cyclopentane, carbon dioxide, n-pentane, nitrogen, butane, isohexane, heptane and chlorodifloro-methane.
1t will be obvious to one skilled in the art various types of catalysts which could be used in the process and reaction of the present invention, and it is intended that all such catalysts are contemplated within the scope of the claims herein. Without limitixAg the generality of the foregoing, however, it is contemplated that the catalysts might be one or more nucleating agent, such as polynethyl siloxane or selections iiom the group Resend 5-25-0~; 4:28PM;Furman & Kallio R9a ;+i 306 359 6956 # ~2/ 26 including talc, calcium fluoride, sodium phenylphosphinate, aluminum oxide, titanium dioxide, fnely divided polytetrahuoroethylene, tetlon, or pyromcllitic dianhydride (PMDA), sulfuric acid, ron oxide or any base earth metal groups,.and/or might be one or more catalysts selected ifrom the following: dibutyltin dilaurate, maleate, precursors for phenolic resin, urea, melamine, dioctyltin dilaurate, sulphuric acid, sodium acetate, zinc chloride, carbomide, 5-phcnyltctrazole, tart-butyl peroxy 2-ethylhexyl carbonate, tart-butyl peroxy-3,5,5-trimcthylhcxanoato, 2,5-.Uiznethyl-2,5-di(tert-butylperoxy)hexane, tart-butyl peroxyber~coate. The catalysts might be one or more of these types of cor,~.pounds.
to While the isocyanate discussed above is methylenediphenylene diisocyanatc ("MDi"), it will be understood that any number of other isocyanates or derivatives of isocyanates, such as diisocyanates or triisQcyanates, could be used and it will be understood that all such isocya,nates and derivatives thereof are contemplated within the scope of the claimed invention. Without tirniting the generality of the foregoing, it Is contemplated that some of tlxe isQCyanates which might be used are 4,4'- phenylmathari~ diisocyanate (MI7n, polyn~ethylene polyphcnyl, polyisocyanate (f.A,p~.
The compositions made possible by the present disclosure arc a result of dynamic curing of the isocyanate in th.e presence of a catalyst which both serves to transitionally cure the carries resin while polymerizing the isocyanatc, thus forming minute interpenetrating networks which act as membranes to any foam cells which are formed in situ in the PET
or other first polyzz~ez~ .resin. It is this aspect, namely the formation of the interpenetrating network, as has been discovered, that causes the extremely fme dispersioxt az~d zetention of closed foam cells, even at extremely high die exit temperatures, e.g.
500°F. This is done without the need to branch the PET as described in much of the prior art.
The 1PN
a composition formed also produces solid polymers with much improved mechanical properties without the loading of large amounts of modif~ring secondary polymers as the prior arts teach. This makes the properties of tl~e composition thus produced far more m Resend 5-25-Ot; 4:28PM;Furman & Kallio R9a ;+~ 306 359 6958 # 13/ 26 resemble those of the parent PET than the trade-off properties which are experienced when employing the prior art.
C
Epoxy compounds could also be employed in the production of the modified PET
or first 5 polymer of the present invention. Various epoxy compounds could he used and it will be understood that all such epoxy compounds are contemplated within the scope of the prevent invention, but without limitang the generality of the foregoing it is specifically thought that the epoxy compounds might include phenols, bisplienols, aromatic epoxy resin and cycloaliphatic epoxy resin. As well, it will be understood tlaat more than one 10 isocyanate and/or epoxy compound might be used in a blend. It is contemplated that isocyanates ar epoxy compounds will be pt'eseot in the amount of .over 0.01 weight percent of the first polymer used in the campvsition- It will be understood that variations in the components the secondary polymer, the eatfi,lyst or catalysts and the isocyanatcs ar epoxy compotuads, as dictated by the application to which the compound is to be applied, are contczxtplated within the scope of the present invention as well.
,An oxygen barrier such as vinyl siloxane could also be added to the product of the present invention and it will be understood that variations in the oxygen barrier employed are also contemplated within the scope of the present invention. Similarly various heat stabilizers could be employed, which it will also be understood are contemplated within the scope ofthe presex~.t invention.
The method of blending employed in the production of the modified thermoplastic composition of the present invention can have a controlled and preferable effect on the final product as well. if an aggressive or dynamic blending process is employed a mart homogenous product will be yielded, since the dynamic blending will cause the size of the particle dispersion in the IfNs created to diminish. A hpmagenous product such as this with a lower dispersion will yield a higher tensile strength thennoplastie composition. Altcmativcly, it may also in certain circumstances be desiured to produce a thermoplastic composition with a lower tensile characteristic or the like, in which case a Resend 5-25-0~; 4:28PM;Fu~man 8~ Kal~io Rga ;+~ 306 359 6956 # 14/ 26 ii nzpre passive blending method z~cti~ht be employed. It will be understood that both types of thermoplastic composition, namely those produced by dynamic or non-dynann.i.c blending, as well as the process of the present invention employing either dynamic or non-dynamic blending, are contemplated within the scope of the present invention.
The product, a ra.vdified thermoplastic composition of a durst primary polymer, of the present invention exhibits better attributes than a standaz~ sample of said first polymer.
For example, where the first polymer is PET the present invention yields a product with a markedly higher intrinsic viscosity than a standard PET sheet. The following graph shows the intrinsic viscosity of a sheet of modified i'ET (marked as Davilon thereon) of the present invention in comparison to a standard PET sheet:
Intrinsic Viscosity 7.4 --.
1.2 _..
... . ..._ ....
0 ..-_...
, -- . O Intrinsic Vscosity D (tlUg) . ...
. ...._._ .
o ... __.
a . f~
a o n Devilon $Iandrd PE'T t l Sheet St,eet 1S Similarly, the product of the present invention also exhibits other better material properties than a standard sample of a first polymer being PET or otherwise.
For i~
Il A
Resend 5-25-0~; 4:28PM;Furman & Kallio Rga ;+~ 306 359 6956 # ~5/ 26 )42-02-OS
lz example, the thermoplastic composition of the present invention will exhibit a better co efficient of thermal expansion, greater tear strength, increased flexural modules, improved elongation or tensile strength characteristics and/or Ga,mder impact performance than standard samples of the first polymer being modifed in accordance with the present invention.
Method of prod coon of thermoplastic composition:
The discussion of the product, thermoplastic composition, above it will be understood is equally applicable to the details of the process ofproduction of same outlined below. As outlined in the claims hcr~;of, the modified thermoplastic composition produced by tlxe process of the present invention is produced by tht dynamic melt blending of the various components. The most preferred zzxethod of producing the compounds is by way of melt blending in a thermoplastic extruder. Either a single or twin screw extruder could be used. Alternatively, an application unit such as a,n injection molding unit could also be used to perform the melt blending operation to produce the modified PET of the present invention. It will be understood that any other type of an apparatus which can be used to melt blend the composition of the present invention is also contemplated within the scope hereof.
One preferred embodiment of the preaent invention is the utilization of a low IV (U-GS to U.75) PET as the first polymer in combination with dibutyltin dilaurate together with linear low-donsity polyethylene and MDI. As outlined in detail herein, these components might be v<~,ri~;d without departing from the scope of the claimed iz~veution, In one exaxnple, a component batch of 97.17% by weight PET, 2% by weight linear low-density polyethylene, 0.03% DBTL (catalyst) and 0.8% MDI (methylenediphenyle"e diisocyanate) were processed at 530 degrees Fahrenheit in a barrier single screw extruder (30:1 LxD), and at the completion of the dynamic melt blending the dye exit temperature was 505 degrees Fahrenheit.
Resend 5-25-Oi; 4:~gPM;Furman & Kallio R9a ;+7 306 359 6956 # ~6~ 26 Preferably, the PET and catalyst, together with the polymer used to form the structure, are introduced at the feed throat of the extruder, with the MDt injected at a port in the extruder barrel after melt blending has occurred, although in practice, the introduction of alt components at the feed tb~z~oat has proven quite satisfactory in producing the compounds described herein. The PET resin and compounds can be preblendcd and or dry blended provided the catalyst's sensitivity to heat is not an issue.
Alternatively, such catalyst rnay be added separately at tlac feed throat.
The catalyst cov~ld be added or present at a level of 0.401 to 10.0 weight percent, based on the weight of the first polymer.
Weight percentages of catalyst Mbil in the production of low-density foam may be irt the area of 0.1 to 3.0 weight percentage of the first polymer, and, in the case of high-density non.-foamad compounds, as high as f weight percent. The blended materials are heated during extrusion to a temperature in the range of 4$0°F to 560°F, or at a minimum to the melt phase of the higher melt first polymer being incorporated, provided it does not exceed the temperature where the lower melt secondary polymer would deteriorate, with sufficient residenc~r time as to allow the diisocyanate to be extensively dispersed aztd cured so as to create the IPN sub stzucture. The dynamic melt blending of the product 24 could take place at any melt teanperature which is sufficient to ensure at least two phases have 3-dimensional spatial continuity resulting from the dynamic ~uriztg in the presence of the catalyst. Tandem extrusion may be used where optimum characteristics aid control of the finished composition or foam is preferred.
ZS A. .hydrocarbon gas might be added during melt-blending. other additives which might be added during the melt bleztding include one or more of antioxidants, stabilizers, dyes, flame-retardants, c;xtenders, UV stabilizers and other processing aids. Where heat stabilizers are added to the process or product of the present invention, the heat stabilizers) might be compounded into an IrVA carrier resin or vinyl based carrier resin 30 or alternatively added directly during processing. The carrier resin might be a polyolefirt t=
p Resend 5-25-0~; 4:28PM;Furman & Kallio R9a ;+~ 306 359 6956 ~ ~7/ ~6 9az-oz-os which comprises from 2 to 6 carbon aton,5. Similarly, the catalyst might be added directly to the composition or process, or might be compounded into an elastomer for addition. Specifically, the catalyst might optionally be compounded into a CPE
p~lyalt~.
Vinyl siloxane might also be added during the blending process, in a sufficient amount to form a surface oxygen barrier. Alternatively the PET conxposike might be coated with an oxygen inhibiting barrier coat compaCible with the PET resin upon exiting the extruder or other blending unit.
lU
The blended thermoplastic could be rapidly cooled upon exiting the blending vessel. it could be cooled in either sheet or pellet form, amongst others, dependent upon the secondary manufaehuing processing requirements. Where foaming agents had teen added in or shifted to a gaseous state during the blending, rapid cooling might optazz~ally trap the foaming agent within the thermoplastic in a liquid phase such that in secondary manufacturing upon rebeating of the PET product, the foaming agent would shift back to its gaseous state and the need for separate addition of foaming agents in secondary manufacturing could be lessened.
The product of any variation of the process of the present invention outlined herein, is contemplated within the scope of the claimed invention as well, Thus it can be seen that the invention accomplishes all of its stated objectives. The foregoing is considered as illustrative only of the principles of the invention. Further, since nuxz~orQus changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.
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Claims (68)
1. A thermoplastic composition created from the melt blending of a first polymer together with a secondary polymer in the presence of a catalyst, together with at least one isocyanate or epoxy compound.
2. The composition of claim 1 wherein an interpenetrating network is created within said thermoplastic composition.
3. A thermoplastic composition created from the blending of a melted first polymer together with a secondary polymer in the presence of a catalyst, together with at least one isocyanate or epoxy compound, said blending resulting in the formation of at least one interpenetrating network within said thermoplastic composition.
4. The composition of Claim 1 wherein said secondary polymer is incompatible for blending with said first polymer.
5. The composition of Claim 1 wherein said secondary polymer is compatible for blending with said first polymer.
6. The composition of Claim 1 wherein said components are dynamically blended.
7. The composition of Claim 1 wherein said components are not dynamically blended.
8. The composition of Claim 1 wherein said secondary polymer is dissimilar to said first polymer.
9. The composition of Claim 1 wherein said first polymer is polyethylene terephthalate.
10. The composition of Claim 9 wherein an interpenetrating network is created within said thermoplastic composition.
11. The composition of Claim 9 wherein said first polymer comprises between 60 to 99 weight percent of the total blend.
12. The composition of Claim 1 wherein said first polymer is a recyclate.
13. The composition of Claim 1 wherein said secondary polymer is a polycarbomide.
14. The composition of Claim 1 wherein said catalyst is compound into said secondary polymer in advance of blending.
15. The composition of Claim 1 wherein said isocyanate or epoxy compound is methylenediphenylene diisocyanate ("MDI").
16. The composition of Claim 1 wherein the number of isocyanate or epoxy compounds is one.
17. The composition of Claim 1 wherein the number of isocyanate or epoxy compounds is more than one.
18. The composition of Claim 1 wherein said catalyst is present at a level of 0.001 to 5.0 weight percent, based on the weight of said first polymer.
19. The composition of Claim 1 wherein said secondary polymer used is in the range of 1 to 40 weight percent of the total blend.
20. The composition of Claim 1 wherein said isocyanate or epoxy compound used is in the range of 0.1 to 3.0 weight percent, based on the weight of said first polymer.
21. The composition of Claim 1 further comprising vinyl siloxane as an oxygen barrier.
22. The composition of Claim 1 further comprising at least one heat stabilizer component.
23. A process for creating a thermoplastic composition, said process comprising melt blending of the following components at a melt temperature:
a) a first polymer;
b) a secondary polymer;
c) at least one catalyst; and d) at least one isocynate ar epoxy compound.
a) a first polymer;
b) a secondary polymer;
c) at least one catalyst; and d) at least one isocynate ar epoxy compound.
24. The process of Claim 23 wherein said thermoplastic composition contains at least one interpenetrating network.
25. The process of Claim 23 wherein said melt blending is dynamic.
26, The process of Claim 23 wherein said melt blending is not dynamic.
27. The process of Claim 23 wherein said secondary polymer is incompatible for blending with said first polymer.
28. The process of Claim 23 wherein said secondary polymer is dissimilar to said first polymer.
29. The process of Claim 23 wherein said secondary polymer is compatible for blending with said first polymer.
30. The process of Claim 23 wherein said first polymer is polyethylene terephthalate.
31. The process of Claim 23 wherein an interpenetrating network is created within the thermoplastic composition.
32. The process of Claim 23 wherein said secondary polymer is from the group of aliphatic and aromatic polyolefins.
33. The process of Claim 23 wherein said secondary polymer is from the group:
polyethylene, ethylene vinyl acetate or polypropylene.
polyethylene, ethylene vinyl acetate or polypropylene.
34. The process of Claim 23 wherein said at least one catalyst is a nucleating agent.
35. The process of Claim 23 wherein said secondary polymer is a polyamite.
36. The process of Claim 23 wherein said secondary polymer is an EVA
copolymer.
copolymer.
37. The process of Claim 23 wherein said nucleating event is polydimethyl siloxane.
38. The process of Claim 23 wherein said at least one catalyst is selected from the group: dibutyltin dilaurate, maleate, precursors for phenolic resin, urea, melamine, dioctyltin dilaurate, sulphuric acid, sodium acetate, zinc chloride, carbontide, 5-phenyltetrazole, tert-butyl peroxy 2-ethylhexyl carbonate, tert-butyl peroxy-3,5,5-trimethylhexanoate, 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl peroxybenzoate.
39. The process of Claim 38 wherein the number of catalysts is one.
40. The process of Claim 38 wherein the number of catalysts is more than one.
41. The process of Claim 23 wherein said isocynate is selected from the group:
4,4'-phenylmethane diisocyanate (MDI), polymethylene polyphenyl, polyisocyanate (PAPI).
4,4'-phenylmethane diisocyanate (MDI), polymethylene polyphenyl, polyisocyanate (PAPI).
42. The process of Claim 23 wherein said epoxy is selected from the group:
phenols, bisphenols, aromatic epoxy resin and cycloaliphatic epoxy resin.
phenols, bisphenols, aromatic epoxy resin and cycloaliphatic epoxy resin.
43. The process of Claim 23 wherein the melt temperature is sufficient to ensure at least two phases have 3-dimensional spatial continuity resulting from the dynamic curing in the presence of said catalyst.
44. The process of Claim 23 further comprising addition of a hydrocarbon gas during blending.
45. The process of Claim 23 wherein said first polymer is from a scrap source.
46. The process of Claim 23 wherein residues of barrier-coatings are present in said first polymer.
47. The process of Claim 46 wherein said barrier-coatings are polyamides or florocarbons.
48. The process of Claim 23 further comprising the addition of at least one hydrocarbon foaming agent during said melt blending.
49. The process of Claim 48 wherein said hydrocarbon foaming agent is selected from the group of isopentane, cyclopentane, carbon dioxide, n-pentane, nitrogen, butane, isohexane, heptane and chlorodifloro-methane.
50. The process of Claim 23 wherein said catalyst is at least one nucleating agent selected from the following group: talc, calcium fluoride, sodium phenylphosphinate, aluminum oxide, titanium dioxide, finely divided polytetrafluoroethylene, teflon, or pyromellitic dianhydride (PMDA), sulfuric acid, iron oxide or any base earth metal groups.
51. The process of Claim 23 wherein said catalyst is added at a rate of between 0.001 to 5 weight percent, based on the weight of said first polymer.
52. The process of Claim 23 further comprising the addition of at least one of the following additives during blending: antioxidants, stabilizers, dyes, flame-retardants, extenders, UV stabilizers and processing aids.
53. The process of Claim 23 further comprising the addition of vinyl siloxane in a sufficient amount to form a surface oxygen barrier in the completed product.
54. The process of Claim 23 wherein said melt blending is performed in an extruder.
55. The process of Claim 54 further comprising coating said thermoplastic composition with an oxygen inhibiting barrier coat compatible with said first polymer upon its exiting the extruder.
56. The process of Claim 23 wherein said melt blending is performed in an application unit.
57. The process of Claim 56 wherein the application unit is an injection molder.
58. The process of Claim 23 wherein said catalyst is present at a level of 0.001 to 10.0 weight percent, based on the weight of said first polymer.
59. The process of Claim 23 further comprising the addition of at least one additional heat stabilizer during the moll blending.
60. The process of Claim 59 wherein said catalyst and said additional heat stabilizer are compounded into an EVA carrier resin or vinyl base carrier resin
61. The process of Claim 23 wherein said catalyst is compounded into an elastomer.
62. The process of Claim 23 wherein said catalyst is compounded into a CPE
polyolefin.
polyolefin.
63. The process of Claim 60 wherein the carrier resin is a polyolefin which comprises from, 2 to 6 carbon atoms.
64. The process of Claim 23 further comprising rapidly cooling the blended thermoplastic composition upon completion of the melt blending step.
65. The process of Claim 48 wherein said at least one foaming agent changes phases from gas to liquid form upon cooling of the blended thermoplastic composition.
66. The process of Claim 48 wherein said at least one foaming agent is present in the cooled thermoplastic composition in such a fashion that said thermoplastic composition can be foamed in secondary manufacturing.
67. The process of Claim 64 wherein said blended thermoplastic is cooled in pellet form.
68. The process of Claim 64 wherein said blended thermoplastic composition is cooled in sheet form.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2348820 CA2348820A1 (en) | 2000-05-26 | 2001-05-25 | Modified thermoplastic composition and method of production of same |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002309508A CA2309508A1 (en) | 2000-05-26 | 2000-05-26 | Modification of polyethylene terephthalate (pet) |
| CA2,309,508 | 2000-05-26 | ||
| CA 2348820 CA2348820A1 (en) | 2000-05-26 | 2001-05-25 | Modified thermoplastic composition and method of production of same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2348820A1 true CA2348820A1 (en) | 2001-11-26 |
Family
ID=25681832
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2348820 Abandoned CA2348820A1 (en) | 2000-05-26 | 2001-05-25 | Modified thermoplastic composition and method of production of same |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2348820A1 (en) |
-
2001
- 2001-05-25 CA CA 2348820 patent/CA2348820A1/en not_active Abandoned
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