Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/12—Hydrolysis
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F12/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F12/02—Monomers containing only one unsaturated aliphatic radical
  • C08F12/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F12/14—Monomers containing only one unsaturated aliphatic radical containing one ring substituted by hetero atoms or groups containing heteroatoms
  • C08F12/22—Oxygen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F212/06—Hydrocarbons
  • C08F212/08—Styrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F212/14—Monomers containing only one unsaturated aliphatic radical containing one ring substituted by heteroatoms or groups containing heteroatoms
  • C08F212/22—Oxygen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/30—Introducing nitrogen atoms or nitrogen-containing groups
  • C08F8/32—Introducing nitrogen atoms or nitrogen-containing groups by reaction with amines
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2438/00—Living radical polymerisation
  • C08F2438/02—Stable Free Radical Polymerisation [SFRP]; Nitroxide Mediated Polymerisation [NMP] for, e.g. using 2,2,6,6-tetramethylpiperidine-1-oxyl [TEMPO]

Definitions

• the field of the invention encompasses plasticizers, in particular, alternative polyphthalate compounds comprising well-defined short polymers containing pendant phthalate esters that under common environmental conditions do not release phthalate esters into the environment, which are known to be endocrine disruptors.
• the field of the invention also encompasses methods for making and using such compounds and plastics (such as PVC) blended with such compounds.
• Phthalates also called phthalate esters
• phthalate esters have been used very commonly (approx. 6 million tons per year) for the formulation of PVC consumer products. Phthalates are relativly easily leached from the plastic matrix into the environment due to the fact that there is no covalent bond between the phthalates and plastics in which they are mixed. As plastics age and break down, the rate of release of phthalates accelerates. In use, phthalate esters leach from the polymer matrix, and when metabolized, can give rise to molecules that, to certain endocrine receptors, structurally and functionally resemble hormones, and therefore act as endocrine disruptors.
• phthalate esters DEHP, DBP (dibutyl phthalate) and BBP (butylbenzyl phthalate) in toys and other child care articles was forbidden by the European Union in 2005, and was banned by the Consumer Safety Commission in 2009 in the United States for toys marketed to children younger than 12 years old, and child care articles for children up to age 3.
• phthalate plasticizers continue to be used for food packaging, medical devices and some toys, and also in articles such as rain coats and cosmetics. Phthalate plasticizers are also used in many other products such as automobile interiors, PVC pipes for drinking water. Such uses are causing increasing medical concern as data accumulates and awareness grows.
• Patent DE 4338124 These publications are hereby incorporated by reference for all purposes. The fact that these references are cited is not an admission that they are prior art.
• polyphthlates that might be ingested cannot be metabolized into hormone mimics. This could revolutionize the plastics industry: most immediately providing solutions for children's products, food packaging, and medical applications.
• the invention encompasses polyphthalate compounds comprising polymers containing pendant phthalate esters that under common environmental conditions do not release phthalate esters (which are known to be endocrine disruptors) in any significant amount.
• the invention also encompasses methods for making such compounds.
• the methods of making the compounds of the invention may use any suitable type of polymerization reaction, many of which are known in the art. For example, Nitroxide Mediated Radical Polymerization (NMRP) may be used. Other controlled and uncontrolled polymerization reactions may be used with one or more type of monomer reactant.
• the invention also encompasses compositions comprising a plastic in need of plasticization (such as PVC) blended with such compounds, and articles made with such compositions.
• polymers containing pendant phthalate esters are prepared by Nitroxide Mediated Radical Polymerization (NMRP).
• NMRP Nitroxide Mediated Radical Polymerization
• the products may be used as plasticizers when blended with polyvinyl chloride (PVC) and other plastics.
• 4-vinylphthalate ester monomers are polymerized in a controlled manner by NMRP to give short polymers consisting of a covalent carbon chain backbone bearing phthalate ester side-groups. Hydrolysis of these designed polymers will release only alcohols, rather than phthalates. Thus degradation products cannot be metabolized to give hormone mimics that may cause endocrine disruption. Both homo- and co-polymers are prepared by the method of the invention, allowing the preparation of polymers with variable molecular weights, variable spacing between phthalate moieties, and variable polarity.
• the invention encompasses (but is not limited to) the following embodiments:
• These experimental conditions are as follows: Hydrolysis of PVC/polyphthalate films are performed by aging the films for 10 weeks at 37 °C, and alternatively at 70 °C in water at neutral and low pH following the procedure described in: Wang, Q.; Storm, B. K., Migration of additives from poly(vinyl chloride) (PVC) tubes into aqueous media.
• ASTM methods are used to probe plasticizer extractability in organic solvents: ASTM D1239 - 07 extraction into hexanes at 50°C with mechanical stirring, and ASTM D2222 - 09 extraction into methanol with mechanical stirring (ASTM D1239 - 07 ("Standard Test Method for Resistance of Plastic Films to Extraction by Chemicals". In ASTM International, West
• a polyphthalate compound comprising polymers containing pendant phthalate esters that under experimental conditions release no detectable amount (less than 1% or alternatively less than 3%) of phthalate esters.
• An assay used to measure the release of phthalate esters by hydrolysis of PVC/polyphthalate films may be performed by aging the films for 10 weeks at 37 °C (alternatively at 50°C, 60°C or 70°C) in water at neutral (and alternatively low) pH following the procedure described by Wang (see above).
• a method for altering the physical properties of PVC by mixing the PVC with a plasticizer wherein the plasticizer is a polyphthalate polymer compound comprising low molecular weight (2000 - 25000) polymers having pendant phthalate esters that under experimental conditions do not release phthalate esters.
• the molecular weight of the polymers may be, for example, 500 to 2500000, or 1000 to 2000000, or 1500 to 1000000, or 2000 to 500000.
• Mixing may be done, for example, by solution casting (Lindstrom, et al., Journal of Applied Polymer Science 2006, 100, (3), 2180-2188) or may be done by any other suitable method of mixing such as simple mechanical mixing at a temperature that encourages blending of components.
• NMRP Nitroxide Mediated Radical Polymerization
• polymerization is carried out at a temperature between, for example 120°C and 126°C using unimolecular alkoxyamine initiators. Alternatively a higher or lower temperature range may be used, for example, temperatures may be 110°C to 140°C or 40°C to 200°C or 60°C to 175°C or 80°C to 155°C or 100°C to 150°C orl00°C to 135°C or 110°C and 130°C.
• the polymerization can be carried out neat (without a solvent) in the monomer without the presence of a solvent to produce short polymers of a covalent carbon backbone bearing phthalate ester side-groups.
• a solvent may be used for the polymerization reaction.
• polymerization may be done by any other known method.
• the defined steps can be carried out in any order or simultaneously (except where the context excludes that possibility), and the method can optionally include one or more other steps which are carried out before any of the defined steps, between two of the defined steps, or after all the defined steps (except where the context excludes that possibility).
• first and second features this is generally done for identification purposes; unless the context requires otherwise, the first and second features can be the same or different, and reference to a first feature does not mean that a second feature is necessarily present (though it may be present).
• reference is made herein to "a” or “an” feature this includes the possibility that there are two or more such features.
• Plasticizer is used herein to describe any substance added to a polymer to chance plasticity, viscosity, fluidity, hardness or another physical quality of the polymer.
• Plastic refers to any polymeric organic amorphous solid compound that is moldable when heated and includes, for example PVC, acrylics, polyesters, silicones, polyurethanes, and halogenated plastics.
• the applicant may mean a polymer with a DP (degree of polymerization) of between 2 and several thousand, for example 40 and 1000 or 10 and 100.
• Hormone is used herein to describe any compound that interacts with the endocrine system of an animal.
• Endocrine disruptor is used herein to describe any compound that interferes with the normal physiological functioning of the endocrine system of an animal.
• a plasticizer does not release phthalate esters, in this disclosure, means that it does not release an appreciable amount of phthalate esters, or alternatively that it releases less than the amount of phthalate esters that a commonly used traditional plasticizer will release over the same period of time under the same conditions; for example no more than 10% or 20%. In other embodiments it may release no more than 30%, 40%, 50%, 60%, 70% or no more than 80% of phthalate esters that a commonly used traditional plasticizer will release over the same period of time.
• One defined method of measuring release is the Wang (above) method of aging a film for 10 weeks at 37°C in water at neutral pH (e.g. 7 to 7.4).
• a plasticizer made of short polymers consisting of a covalent carbon chain backbone bearing phthalate ester side-groups may release less than 30% (or alternatively less than 20%, 10%, 5%, 3%, 1% or less than 0.5%) of the phthalate esters that would be released, over the same period under the same conditions, by a plasticizer not made of short polymers consisting of a covalent carbon chain backbone bearing phthalate ester side-groups.
• plasticizers used for PVC (polyvinylchloride) products are branched alkyl phthalate esters of low molecular weight such as di-2-ethylhexyl phthalate (DEHP) 1 and diisononyl phthalate (DINP) 2 ( Figure 1).
• DEHP di-2-ethylhexyl phthalate
• DIHP diisononyl phthalate
• Figure 1 The plasticizing effect is based on an increase of the free volume per volume of material, which results in a decrease of the glass transition temperature.
• pure PVC is inherently a rigid and brittle material
• the macroscopic effect of the addition of plasticizers is increased flexibility and workability, a reduced melt viscosity and lower elastic modulus.
• phthalates are not covalently bonded to PVC, they leach out of the polymer matrix into the environment. Humans are exposed to phthalates from a wide range of products such as food packaging, medical devices and toys. Studies on the migration of low molecular plasticizers and their decomposition products into food and biological fluids like saliva or blood and the resulting health risk have raised serious health concerns. Animal studies have shown that some phthalates, such as DEHP and their metabolic products, behave as Endocrine Disrupting
• Polymeric plasticizers demonstrate decreased migratory aptitude in comparison to small molecule phthalate plasticizers.
• Polyesters such as poly(s-caprolactone) (PCL) 3 and poly(butylene adipate) (PBA) 4 ( Figure 2), have been investigated as polymeric plasticizers since 1947.
• Hubbel reported that poly(s-caprolactone) is compatible with PVC in a concentration range of 10% - 90%, and demonstrates efficient plasticizing properties.
• the plasticizing behavior of commercial elastomers such as polycaprolactone glycol-based thermoplastic urethanes (PCL/TPU Estane 54351 and PE/TPU Estane 58213 developed by Goodrich),
• poly(ethylene- co-vinyl acetate-co-carbon monoxide) terpolymers (Elvaloy 741 and Elvaloy 742 developed by DuPont) and poly(l,3-butylene adipate) (REOPLEX® developed by Ciba-Geigy) have been investigated. These polymers are miscible with PVC, and display reduced migration in comparison to low molecular plasticizers, while their plasticizing effects are useful for specific applications.
• the influence of molecular weight and branching of poly(butylene adipate) s on the plasticizer efficiency and migration aptitude was recently studied by Hakkarainen.
• the major disadvantages of these polyesters is that the polymer backbone is susceptible to hydrolysis, which changes their physical properties with aging and exposure to moisture.
• polyesters as plasticizers are characterized as low, medium or high molecular weight plasticizers, with average molecular weights ranging from 1,000 to 10,000. While the migration resistance improves with increasing molecular weight, the processability decreases.
• Miscibility Molecular dynamics simulations by Lee of polyester blends with PVC indicate that a ratio of 3-4 methylene units per ester is a lower limit for miscibility, while the upper limit is 10-12 methylene units per ester, with an optimal ratio of 6 methylene units per ester, which is corroborated by experimental data: the melting point depression method gave an optimal ratio of 7, whereas thermodynamic
• Branching Slightly branched polymers enhance the plasticizing effect in terms of greater elongation and improved miscibility. Due to the higher density of chain ends in branched polymers, the free volume and mobility is higher in comparison to linear polymers with the same molecular weight. However high degrees of branching result in low miscibility and poor mechanical properties. Concentration: A concentration of approximately 40 wt % of polyester plasticizer is needed to obtain materials with elastomeric behavior. Endgroups: The polyester endgroups play a role in moderating the susceptibility of the polymeric plasticizer to hydrolysis. This effects the subsequent migration of monomeric degradation products from the PVC matrix. The inherent degradability of polyesters, leading to lower molecular weight hydrolysis products, makes these plasticizers of limited usefulness. Thus a robust, non-hydrolysable polymeric plasticizer with a non-hydrolizable backbone is desirable.
• the present invention entails preparation of poly(vinylphthalate ester)s, as homopolymers, or random copolymers with styrene, acrylates or other comonomers, to be used as substitutes for standard phthalate plasticizers in PVC.
• poly(vinylphthalate ester)s as homopolymers, or random copolymers with styrene, acrylates or other comonomers
• phthalate esters are now used on the million ton scale annually, a substitute is desirable that is chemically similar, but which shows low migratory ability from the PVC matrix.
• these poly(vinylphthalates) are linked together by a robust carbon polymer backbone: hydrolysis will release only alcohols, rather than phthalates. Thus degradation products pose no danger of being metabolized to form Endocrine Disruptor Compounds.
• NMRP Nitroxide-mediated radical polymerization
• the alkoxyamine based on the alpha-hydrogen bearing nitroxide TIPNO T-butyl-isopropyl- phenyl-nitroxide
• the very similar initiator BLOCKBUILDER ® initiator based on the alpha-hydrogen bearing nitroxide SGI (13) is available commercially on large scale from Arkema Inc.
• NMP is an attractive method for this application.
• the polymerizations are typically carried out by heating in the range of 120-126 °C (other temperature ranges are possible - see above) using unimolecular alkoxyamine initiators, neat in the monomer (alternatively a solvent may be used).
• the radical nature of the polymerization makes this a chemoselective technique that is tolerant to a variety of functional groups on the monomers including esters, anhydrides, amides, alcohols, amines, epoxides, nitriles, and carbamates.
• the "Living" nature of the radical polymerization gives polymers of predicable molecular weights (e.g., PDI from about 1.2 to 1.8), and as no solvent is employed, the polymerizations are economical and scaleable to prepare bulk commodities at the industrial level.
• solvent may be employed (but generally is not). Solvent may be added to ensure solubility of all of the components.
• super critical C0 2 may be used as the solvent.
• a number of vinyl boron agents have been used to carry out this transformation on aryl bromides, including protocols by Molander and Najera with potassium vinyltrifluoroborate. Joucla has developed a heterogeneous palladium catalyst to be used with potassium vinyltriflouroborates. Alternatively, the use of vinyl boronic acids have been used by a number of research groups.
• 4-vinylphthalic anhydride 26 from 4-vinylphthalic acid 15 by sublimation.
• 4-bromophthalic acid should be easily converted in to the corresponding anhydride, followed by vinylation. This will allow for easier handling of the intermediates, without concerns of premature polymerization during storage.
• plasticizer is DEHP, thus 2-ethylhexyl
• polymerizations to form homopolymers and copolymers is carried out using NMRP.
• the resulting polymers is initially characterized by 1H- NMR of the crude polymerization mixture to determine the ratio of consumed to residual monomer, and then GPC to determine molecular weight and polydispersity.
• Short homopolymers using 4-vinylphthalate esters are prepared, varying the molecular weights between 2,000 - 25,000 (DP ⁇ 4 - 24), or in other embodiments between, for example 10 and 40.
• the miscibility properties of these materials with PVC are unknown.
• they are tested for efficacy as plasticizers, as indicated by the glass transition temperature and tensile strength of the resulting blends.
• a variety of 4-vinylphthalate monomers is investigated, by varying the alcohols making up the phthalate esters, and varying the molecular weight of these homopolymers.
• the TEMPO-based initiator is used for these polymerizations, as it is less costly than the H nitroxide-based initiators. It is understood that TEMPO, TIPNO, or many other nitroxide-based initiators can be used.
• the bulky phthalic ester moieties may cause the homopolymers to be too rigid to exhibit satisfying plasticizing properties.
• random copolymers prepared by a mixture of 4-vinylphthalate esters and styrenes or acrylates are prepared.
• Styrene as a co-monomer will statistically spread apart the bulky phthalate sidegroups, but the parent polymer backbone is essentially polystyrene.
• acrylates will form copolymers that have polarity properties more closely related to the polyester plasticizers used today, without the susceptibility to backbone hydrolysis. It is possible that the acrylate "spacers" will act to isolate the bulky phthalate groups, allowing these copolymers to mimic traditional phthalate plasticizers when blended with PVC.
• the optimal ratio determined by Lee of 5-7 methylene to ester units in polyesters to achieve maximal miscibility with PVC indicates that rc-butyl acrylate is a good initial choice.
• a slightly branched alcohol such as isobutyl alcohol is another good choice.
• a polymer with molecular weights of 2000 - 10000 (DP ⁇ 4 - 24) is synthesized from 4-vinylphthalic esters and acrylates by NMRP. For these
• An alternative embodiment encompasses the use of 4-vinylphthalic anhydride as a co- monomer, to provide for the opportunity of post polymerization modification.
• Variables include: alcohol on phthalate ester; molecular weight of polymer; identity and ratio of comonomer (for acrylates, alcohol of acrylate is another variable); ratio of polyphthalate plasticizer blended with PVC.
• Solution cast films of PVC mixed with our designed phthalic ester polymers are prepared as described by Hakkarainen. These polymer blends are analyzed for miscibility and plasticizing effect, as well as stability.
• Miscibility Miscibility between the PVC and the polymeric phthalate plasticizers is determined by IR- spectroscopy and differential scanning calorimetry (DSC). Interactions between the CH 2 -C1- groups of PVC and the carbonyl groups of the polyesters are indicated by a shift of the carbonyl peak to lower wavenumbers. The existence of a single glass transition temperature is proof of full miscibility.
• Tensile Strength The mechanical properties of PVC/poly(4- vinylphthalic ester) films is investigated by tensile strength analysis, a good method to determine elastomeric behavior. These new polymer blends is compared with PVC containing traditional phthalate plasticizers.
• Glass Transition Temperature The plasticizing properties of the new polymer blends is probed by measuring the glass transition temperature, a good starting property is a T g below -30 °C.
• Stability and migration of polymeric plasticizers Hydrolysis of PVC/poly(4- vinylphthalic ester) films is performed by aging the films for 10 weeks at 37 °C in water. The degradation products is analyzed by GC-MS. Mass loss and water absorption of the films will also be measured.

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• 2013
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