Patent Description:
Methods of forming polyester, thermoplastic urethane and other engineering plastic (EP) compositions having superior mechanical properties by reacting the polyester, thermoplastic urethane and other engineering plastic with an olefin-maleic anhydride copolymer during compounding are described. Also described herein are novel compositions formed by compounding olefin-maleic anhydride copolymers (OMAP) such as ethylene-maleic anhydride copolymers with polyester (PE), thermoplastic urethane (TPU) and other engineering plastics.

Engineering plastics include plastic materials having superior mechanical and/or thermal properties compared to commodity plastics, such as polystyrene, PVC, polypropylene, polyethylene, and the like. Engineering plastics often refers to thermoplastic materials, and include a wide range of materials such as acrylonitrile butadiene styrene (ABS), used for car bumpers, dashboard trim and Lego® bricks; polycarbonates, used in motorcycle helmets; and polyamides (nylons), used for skis and ski boots. Engineering plastics have gradually replaced traditional engineering materials such as wood or metal in many applications. Besides equaling or surpassing wood and metal products in weight/strength and other properties, engineering plastics are much easier to manufacture, especially in complicated shapes. Engineering plastics often possess a unique combination of properties that may make it the material of choice for a particular application. For example, polycarbonates are highly resistant to impact, while polyamides are highly resistant to abrasion. Other properties exhibited by various grades of engineering plastics include heat resistance, mechanical strength, rigidity, chemical stability and fire resistance. As a result of the high degree of variability and wide applicability of their use, engineering plastics have been the subject of much research as development.

Despite large investments in engineering plastics that have been made to-date, there is a great need for the development of engineering plastics having superior properties.

<CIT> describes concentrate compositions (e.g. master batches) comprising olefin-maleic anhydride copolymers and other additives dispersed in various carrier resins and methods for their preparation and use.

The present invention provides a thermoplastic pelletizable compatibilized polymer alloy composition comprising:.

Additional embodiments, features, and advantages of the disclosure will be apparent from the following detailed description and through practice of the disclosure. The polymers of the present disclosure can be described as embodiments in any of the following enumerated clauses. It will be understood that any of the embodiments described herein can be used in connection with any other embodiments described herein to the extent that the embodiments do not contradict one another.

Articles manufactured from those novel compositions are also described herein. It will be appreciated that products which are made from PE, PC and TPU are exposed to considerable stresses during manufacture and processing and eventual end use in the application, and that a composition and method for producing enhanced properties with increased durability are needed. The concept of enhancing performance of individual engineering plastics by compounding with olefin-maleic anhydride copolymers (OMAP) can be extended to compositions that comprise more than one type of engineering plastic, to form useful engineering plastic alloys. In compositions where existing alloys are compatible, the addition of olefin-maleic anhydride copolymers (OMAP) increases mechanical performance. In compositions, where incompatibility exists, the olefin-maleic anhydride copolymer (OMAP) enables the compatibilization of different engineering plastics.

The compositions described herein may be formed by providing an engineering plastic reaction mixture of an engineering plastic or an alloy of engineering plastics with an olefin-maleic anhydride copolymer, and compounding the engineering plastic reaction mixture at a processing temperature.

Described herein are novel compositions formed by compounding olefin-maleic anhydride copolymers, such as ethylene-maleic anhydride copolymers, with an engineering plastic or an alloy of engineering plastics. Compounding an engineering plastic or an alloy of engineering plastics with olefin-maleic anhydride copolymer enhances many properties of engineering plastics or alloy of engineering plastics.

According to the invention, the olefin-maleic anhydride copolymer is an ethylene-maleic anhydride copolymer having a molar ratio of ethylene to maleic anhydride of <NUM>:<NUM>.

Illustrative engineering plastics whose properties can be modified by compounding with olefin-maleic anhydride copolymers a polyester (PE), a terpolymer of acrylonitrile-butadiene-styrene (ABS), a polycarbonate, a polyphenylene ether (PPE), a polyacetal (also referred to as a polyoxymethylene or a polyformaldehyde), a polyamide (a nylon), a polyethylenterephthalate (PET), a polybutylenterephthalate (PBT), a polysulphone (PSU), a polyetherimide (PEI), a polyphenyl sulphone (PPSU), a polyether sulphone (PES), a polyphenylenesulphide (PPS), a polyaryletherketone (PAEK), a polyamidimide (PAI), a polyimides (PI) and combinations thereof (not in accordance with the invention).

Olefin-maleic anhydride copolymers can suitably be used to modify the properties of polyesters (not in accordance with the invention).

The polyesters can be synthetic or natural/bio-based or even thermoset (such as unsaturated polyester that is then cross-linked or cured with peroxide or by other methods). Illustrative examples of polyesters include but are not limited to aliphatic polyesters such as polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), polyethylene adipate (PEA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), and poly(<NUM>-hydroxybutyrate-co-<NUM>-hydroxyvalerate) (PHBV). Additional illustrative examples of polyesters include semi-aromatic polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN) and aromatic liquid crystal polyester (LCP) type polyesters such as Vectra®. Other examples of copolyesters included in the methods and compositions described hereinare PETG and commercial products like EcoFlex® from BASF, Triton® and Eastar® from Eastman Chemicals, and Polyclear® from Invista. It is to be understood that a single polyester or an alloy of one or more polyesters may be used in any of the polymers, methods, or compositions described herein.

Compounding with olefin-maleic anhydride copolymers suitably upgrades recycled or virgin polyester chosen from one or more of the families described above (not in accordance with the invention). As used herein, the term "recycled" includes reprocessed, regrind, scrap and reclaimed polyester from a post-industrial process, a post-consumer source, or an "off-grade" product from a polyester manufacturer. As used herein, "upgrades" refers to improving the mechanical performance of a polyester relative to the unmodified polyester resin. For instance, an upgraded polyester could have increased tensile elongation or tensile modulus.

Condensation polymers such as polyesters are widely used to make plastic products such as films, bottles, and other molded products. The mechanical and physical properties of these polymers are dependent on their molecular weights. These materials may experience an extrusion step and a final processing step which may be another compounding/extrusion operation followed by profile or sheet forming, thermoforming, blow molding, or fiber spinning, or they can be injection or otherwise molded in the molten state. Typically, all of these steps occur under high temperature conditions and may cause some degree of polymer molecular weight degradation. This molecular weight degradation may occur via high temperature hydrolysis, alcoholysis or other de-polymerization mechanisms well known for these types of polyesters. It is known that molecular weight degradation can negatively affect the mechanical and rheological properties of polyesters. These property changes can limit or exclude the use of these materials in demanding applications or from being recycled.

Addition of olefin-maleic anhydride copolymers to polyesters suitably increases the melt viscosity of the polyesters (not in accordance with the invention). It is believed that this increase in melt viscosity may arise via chain extension and/or branching. The olefin-maleic anhydride copolymers are used at levels that show low levels of branching promoting an increase in melt viscosity. The modified polyester with increased melt viscosity and branching is believed to exhibit a non-Newtonian flow which is particularly useful for certain applications, such as extrusion blow molding, roto-forming, fiber forming, film extrusion, profile extrusion, sheet extrusion and thermoforming.

Olefin-maleic anhydride copolymers are suitably used in the form of concentrates dispersed in a suitable carrier resin along with additives. Such concentrates can be referred to as master batches.

In some embodiments, UV stabilizers and absorbents, halogenated or non-halogenated flame retardant additives; reinforcements such a mineral or fibers, fabrics, roving filaments, tubes and yarns, made from glass, carbon, graphite, cellulose and other natural materials; and/or aromatic high melting polymers (sometimes referred to as aramids) are included within the reaction mixture.

In some embodiments, inter-esterification catalysts, esterification catalysts, etherification inhibitors, polymerization catalysts, stabilizers including heat stabilizers and light stabilizers, polymerization regulators, plasticizers, lubricants, rheology modifiers, friction modifiers, an anti-blocking agent, an antioxidant, an antistatic agent, a UV absorber, a pigment, a dye and other additives or stabilizing agents known in the art may also be optionally added to the mixtures described herein.

Suitably, the olefin-maleic anhydride copolymers or its concentrate form are used optionally with other additives typically used in polymer and plastic compounds (thermoplastic and thermoset. Illustrative examples of additives include: fillers, reinforcements, flame retardants, antioxidants and stabilizers, and the like.

Suitably, addition of an olefin-maleic anhydride copolymer is used to alloy two or more polyesters improving the overall mechanical properties of the polyester-polyester alloy compound (not in accordance with the invention).

Suitably, the addition of an olefin-maleic anhydride copolymer is used to alloy polyesters with polyamides improving the overall mechanical properties of the polyester-polyamide alloy compound.

In accordance with the invention, the two non-compatible engineering plastics are (i) thermoplastic polyurethane (TPU) and polybutylene terephthalate (PBT), or (ii) polyamide and polybutylene terephthalate.

Although injection molding is the commonly applied process for the final conversion of the compositions described herein, it is appreciated that, in addition to the processes described herein, the compositions described herein are useful in other processes such as blow molding, roto-forming, fiber forming, film, profile and sheet extrusion and thermoforming.

Illustrative embodiments described herein include use of processing methods such as extrusion compounding using equipment known to one skilled in the art. In the plastics industry, compounding is a process that mixes one or more polymers with one or more additives to produce plastic compounds in one or more steps. The feeds may be pellets, powder and/or liquids, but the product is usually in pellet form, to be used in other plastic-forming processes such as extrusion and injection molding.

Other illustrative embodiments of the methods described herein include directly extruding the compounding mixture into a finished article such as a filament, fiber, film, sheet, and molded part. It is to be understood that the compounding step may include a reaction between one and more of the components of the mixture.

In any of the methods or compositions described herein, one or more UV stabilizers, or UV absorbents, halogenated or non-halogenated flame retardant additives, reinforcements such a mineral or fibers, fabrics, roving filaments, tubes and yarns, made from glass, carbon, graphite, cellulose and other natural materials; and/or aromatic high melting polymers (sometimes referred to as aramids) are included. Plasticizers, lubricants, rheology modifiers, friction modifiers, and other additives known to one skilled in the art may also be optionally added. Additional illustrative additives include, heat stabilizers, light stabilizers, polymerization regulators, plasticizers, lubricants, rheology modifiers, friction modifiers, anti-blocking agents, antioxidants, antistatic agents, pigments, dyes, fillers or mixtures thereof.

According to the present invention, the olefin-maleic anhydride is an ethylene maleic anhydride alternating copolymer (EMA) with a molar ratio of ethylene to maleic anhydride of about <NUM>:<NUM>. The olefin-maleic anhydride copolymers used in the compositions and methods described herein distinctly differ from maleic anhydride grafted polyolefins. In maleic anhydride grafted polyolefins the molar ratio of the maleic anhydride to olefin is generally less than <NUM>:<NUM> and more typically less than <NUM>: <NUM>,<NUM>. Illustrative differences between the olefin-maleic anhydride copolymers used herein and maleic anhydride grafted polyolefins are listed in the following table.

In any of the methods or compositions described herein, the olefin-maleic anhydride copolymer can have a weight average molecular weight (MWw) in the range of about <NUM> to about <NUM>,<NUM> ; about <NUM>,<NUM> to about <NUM>,<NUM>; about <NUM>,<NUM> to about <NUM>,<NUM>; about <NUM>,<NUM> to about <NUM>,<NUM>; or about <NUM>,<NUM> to about <NUM>,<NUM>. In any of the methods or compositions described herein, the <NUM>: <NUM> alternating olefin-maleic anhydride copolymer selected may be a <NUM>:<NUM> alternating copolymer of ethylene and maleic anhydride (<NUM>:<NUM> EMA) with a weight average molecular weight (MWw) of about <NUM>,<NUM> such as that sold under the trademark ZeMac® E-<NUM> (Vertellus Specialties Inc. , E60), or the <NUM>:<NUM> EMA selected may have a weight average molecular weight (MWw) of about <NUM>,<NUM> such as that sold under the trademark ZeMac® E-<NUM> (Vertellus Specialties Inc.

As used herein, the term "compounding" generally refers to a process that mixes one or more polymers with one or more additives to produce plastic compounds in one or more steps. The materials to be mixed may be in the form of pellets, powders and/or liquids. Typically the product is in pellet form for use in other plastic-forming downstream processes such as extrusion and injection molding.

A polymer blend is formed when two polymers are mixed together to create a material with different properties than the two starting polymers. However most polymers are incompatible with one another and hence form many domains of immiscible phases which are rather large in size with almost no interfacial interaction between them. So most polymer blends have properties that are not what one would expect from an arithmetic addition of the properties from the fraction of each polymer property. A polymer alloy is the result when the interfacial adhesion between the two phases is improved sufficiently and the mixture of the two polymers shows synergistic properties such that you end up with improved property performance. This alloy of polymers may result because the two polymers are chemically compatible with one another or be the result of the use of a third component which acts to compatibilize the two immiscible polymers. In such a case, tiny domains of one polymer are formed in the matrix of the other polymer due to good adhesion at the interface between the two polymers. The formation of these dispersed domains results in improved properties compared to a blend of the two immiscible polymers. The third component used to compatibilize the otherwise two immiscible polymers is called a compatibilizer.

A composite is a blend of a polymer with a filler or reinforcing agent, which is used to enhance the properties of a polymer. Compatibilization of alloys, blends and composites requires intimate physical mixing and interfacial bonding or chemical compatibility. Compatibilization of composites enables them to have improved mechanical properties. How well the polymers and/or filler or reinforcement are compatiblized can be determined by morphology or by mechanical properties.

The olefin-maleic anhydride copolymer described herein is not a grafted copolymer with one or two maleic anhydride groups per molecular chain, but a true copolymer with multiple maleic anhydride groups in the main chain of the polymer. The olefin-maleic anhydride copolymers in the methods and compositions described herein have weight average molecular weights (MWw) in the range of <NUM> to <NUM>,<NUM>. In one embodiment, the ethylene-maleic anhydride copolymers are <NUM>:<NUM> alternating copolymers. In one aspect, ethylene-maleic anhydride copolymers sold under the ZeMac® trademark can be used. It is believed that addition of olefin-maleic anhydride copolymers to polyesters enhances mechanical properties of the polyesters by increasing the melt viscosity and/or melt elasticity (i.e. chain extension of the polyester).

In any of the embodiments described herein, the olefin-maleic anhydride copolymer selected for reaction with a polyester and other engineering plastics and their alloys has a weight average molecular weight (MWw) of in the range of about <NUM> to about <NUM>,<NUM>; about <NUM>,<NUM> to about <NUM>,<NUM>; about <NUM>,<NUM> to about <NUM>,<NUM>; about <NUM>,<NUM> to about <NUM>,<NUM>; or about <NUM>,<NUM> to about <NUM>,<NUM>. In any of the embodiments described herein, the <NUM>:<NUM> EMA may have a weight average molecular weight (MWw) of about <NUM>,<NUM> such as that sold under the trademark ZeMac® E-<NUM> (Vertellus Specialties Inc. , E60), or the <NUM>:<NUM> EMA selected may have a weight average molecular weight (MWw) of about <NUM>,<NUM> such as that sold under the trademark ZeMac® E-<NUM> (Vertellus Specialties Inc. Moreover, the EMA may be used in an exemplary embodiment of the method of producing compounded polyester at a concentration of between about. <NUM>% to about <NUM>% w/w; about <NUM>% to about <NUM>%; about <NUM>% to about <NUM>% w/w; about <NUM>% to about <NUM>% w/w; or about <NUM>% to about <NUM>% w/w.

In another embodiment a master batch composition comprising an olefin-maleic anhydride copolymer and one or more additional additives in a matrix of a carrier resin is used. Some desired characteristics of a master batch include: the master batch improves the uniformity of the incorporation of the additives in the final composition, the additives do not phase separate from the carrier resin, the carrier resin does not phase separate with the polymer being formulated, the carrier resin remains thermally stable at the processing temperatures and under the processing conditions typically used for processing engineering plastics, and the presence of the carrier resin in the polymer formulation should not adversely affect the performance of the formulated composition. The choice of the carrier resin can be but not limited to polymers or their combination selected from polyacetal, polycarbonate, thermoplastic polyurethane (TPU), acrylonitrile-butadiene-styrene terpolymers (ABS) and polyester such as polylactic acid (PLA), a polyglycolic acid (PGA), a polycaprolactone (PCL), a polyethylene adipate (PEA), a polyhydroxyalkanoate (PHA), a polyhydroxybutyrate (PHB), a poly(<NUM>-hydroxybutyrate-co-<NUM>-hydroxyvalerate) (PHBV), a polyethylene terephthalate (PET), a polybutylene terephthalate (PBT), a polytrimethylene terephthalate (PTT).

Tensile, flexural, and Izod impact strength measurements were carried out using ASTM methods D-<NUM>, D-<NUM>, and D-<NUM>, respectively at <NUM>. Melt flow rate (MFR) measurements were made following ASTM D-<NUM>. Heat deflection/distortion temperatures (HDT) were measured using ASTM method D-<NUM>. These mechanical and thermal tests were carried out without additional drying. The samples were used as molded after conditioning the test specimen as described in the ASTM protocol. Water absorption tests were carried after drying to equilibration to ensure that all the absorbed water is between <NUM>%-<NUM>% dryness levels.

A <NUM>: <NUM> ethylene-maleic anhydride alternating copolymer grade ZeMac® E60 (E60) from Vertellus Specialties Inc. with a weight average molecular weight (MWw) of <NUM>,<NUM> was used in illustrative examples.

NLP™ clear grade of recycled polyethylene terephthalate (RPET) was obtained from Phoenix Technologies International. Recycled polybutylene terephthalate (RPBT), PBT325 NA EF grade and recycled <NUM>% glass filled, GPB <NUM> NA EF grade was obtained from Lucent Polymers. Ingeo® Biopolymer 3251D grade of polylactic acid (PLA) was obtained from NatureWorks LLC.

Thermoplastic urethane (TPU) Pearlthane 11T93 (Shore A 93A) was obtained from Lubrizol. The thermoplastic urethane is a polycaprolactone co-polyester. Polybutylene terephthalate (PBT), Crastin 6131C was obtained from DuPont. Polycarbonate-Acrylonitrile butadiene styrene alloy (PC-ABS, Grade GP1-<NUM>) was obtained from Polymer Resources Ltd.

Composite pellets of compounded recycled and virgin polyester with ZeMac® E60 were prepared in a co-rotating twin screw extruder (Coperion ZSK-<NUM>). Recycled PET compounding by itself or with E60 copolymer was conducted using temperature settings between <NUM>-<NUM>. The recycled PBT and glass-filled PBT compounds were compounded with or without E60 using temperature settings between <NUM>-<NUM>. The PLA, with or without E60 was processed at temperature settings between <NUM>-<NUM>. Care was taken to ensure that all grades were used dry.

Composite pellets of compounded thermoplastic urethane (TPU) and its alloy polybutylene terephthalate (PBT) with and without ZeMac® E60 were prepared in a co-rotating twin screw extruder (Coperion ZSK-<NUM>). The compounding with and without ZeMac®E60 was processed at temperatures between <NUM>-<NUM>. Care was taken to ensure that all grades were used dry.

Composite pellets of compounded alloy of polycarbonate-acrylonitrile butadiene styrene (PC-ABS) with and without ZeMac® E60 were prepared in a co-rotating twin screw extruder (Coperion ZSK-<NUM>). The compounding with and without ZeMac®E60 was processed at temperatures between <NUM>-<NUM>. Care was taken to ensure that all grades were used dry.

The formulation used for producing compounds of polyester with olefin-maleic anhydride copolymers is shown in TABLE <NUM>:.

Table <NUM> shows the mechanical properties of recycled PET compounded by itself and with E60 copolymer at <NUM>%. The lowering in MFR with olefin-maleic anhydride copolymer result demonstrates that molecular weight of the PET is increasing which is then complimented by increase in flexural modulus and heat deflection temperature.

Table <NUM> shows the results of mechanical properties of recycled PBT compounded by itself and with E60 copolymer. Similar to the results of recycled PET, the recycled PBT compounds with E60 show increased flexural modulus and HDT because of increase in molecular weight as evident by lower MFR results.

Table <NUM> shows <NUM>% glass-filled recycled PBT compounded by itself and the mechanical properties are compared to <NUM>% (example F7) and <NUM>% (example F8) which is equivalent to <NUM>% and <NUM>% E60 equivalent by weight of the polymer. In both the E60 composites with recycled glass-filled PBT the resulting composite shows in enhancement of all the mechanical properties with the exception of HDT in example F7. The improvement in mechanical properties is accompanied by lowered MFR indicating an increased molecular weight.

It is believed that in addition to increased molecular weight, addition of the olefin-maleic anhydride copolymer also enhances the interaction of the glass-fiber with that of recycled PBT resin.

Table <NUM> shows mechanical property of PLA, a biopolymer polyester, whose commercial uses have grown especially for film extrusion, injection molding, blow molding, profile and sheet extrusion.

The results in Table <NUM> show an increase in tensile and flex modulus when PLA is compounded with E60 without affecting the impact strength of the polyester. Unlike other examples described, the MFR of PLA is not reduced by addition of E60 to the polyester.

It is known to one skilled in the art that alloying of two different classes of polyesters, both being compatible materials is useful for achieving polymer mixtures with balance of properties. However, it is very desirable to have such compositions with improved properties. An illustrative example of an alloy of interest is PET with PBT. PET is known to have long cycle times during molding and PBT is typically mixed in PET to ensure fast crystallization and improved impact strength. A PET/PBT alloy of commercial interest is <NUM>%PBT in a PET matrix. It would be very desirable to alloy recycled PET with recycled PBT and to enhance the mechanical property of such alloy.

TABLE <NUM> demonstrates the results of mechanical properties of recycled PET/ PBT alloy by itself and with the olefin-maleic anhydride copolymer (not in accordance with the invention). The results show that adding E60 copolymer improves the mechanical properties of the alloy resulting in a very tough alloyed compound as demonstrated in Example F12.

The compositions and method described here can be used for improving the properties of engineering plastics and enabling the alloying of polyesters with non-compatible engineering plastics. These concepts are demonstrated in the formulations shown in TABLE <NUM>.

The results of the formulation in Table <NUM> are shown in Table <NUM>.

The example F14 shows highly improved mechanical properties of TPU in the presence of ZeMac® E-<NUM> when compared to its control in example F13.

Example F16 and F19 shows very poor mechanical properties when polyester is alloyed with non-compatible TPU and Nylon engineering plastics; however examples F17 and F20 shows highly improved mechanical properties of both the alloys in presence of ZeMac® E-<NUM> demonstrating that ZeMac® E-<NUM> is working as a compatibilizer between two non-compatible engineering plastic matrix.

The formulation used for producing compounds of Polycarbonate-acrylonitrile butadiene styrene (PC-ABS) alloy with olefin-maleic anhydride copolymers is shown in TABLE <NUM>.

Example F21 representing control samples of PC-ABS alloys are well known to one skilled in the art. The mechanical properties of PC-ABS with olefin-maleic anhydride copolymers are shown in Table <NUM>.

Example F22 and F23 demonstrates that ZeMac® E-<NUM> improves all the mechanical properties of alloyed PC-ABS of Example F21.

The compositions described herein can be formed into articles using methods known to those skilled in the art, such as, injection molding, blow molding, extrusion, and the like.

Claim 1:
A thermoplastic pelletizable compatibilized polymer alloy composition comprising:
(a) two non-compatible engineering plastics; and
(b) an ethylene-maleic anhydride copolymer,
wherein the ethylene-maleic anhydride copolymer enables compatibilization of the non-compatible engineering plastics,
wherein the ethylene-maleic anhydride copolymer has a molar ratio of ethylene to maleic anhydride of <NUM>:<NUM>, and
wherein the two non-compatible engineering plastics are (i) thermoplastic polyurethane (TPU) and polybutylene terephthalate (PBT), or (ii) polyamide and polybutylene terephthalate (PBT).