WO2012112542A1 - Agent de nucléation cristallin supporté pour polypropylène - Google Patents

Agent de nucléation cristallin supporté pour polypropylène Download PDF

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Publication number
WO2012112542A1
WO2012112542A1 PCT/US2012/025037 US2012025037W WO2012112542A1 WO 2012112542 A1 WO2012112542 A1 WO 2012112542A1 US 2012025037 W US2012025037 W US 2012025037W WO 2012112542 A1 WO2012112542 A1 WO 2012112542A1
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Prior art keywords
polypropylene
alpha
dispersed particle
dispersed
chemical
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PCT/US2012/025037
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English (en)
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Philip Jacoby
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Mayzo, Inc.
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Publication of WO2012112542A1 publication Critical patent/WO2012112542A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
    • C08K5/0083—Nucleating agents promoting the crystallisation of the polymer matrix
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K9/00—Use of pretreated ingredients
    • C08K9/04—Ingredients treated with organic substances
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/24—Crystallisation aids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/10—Homopolymers or copolymers of propene

Definitions

  • the present disclosure relates to nucleating agents, and specifically to crystal nucleating agents that can be used to produce, for example, polypropylene molded or extruded parts.
  • Crystal nucleating agents are widely used in polypropylene processes to increase the rate of crystallization from the melt, and to increase the level of crystallinity in molded and extruded parts. Using nucleating agents can be beneficial, providing shorter cycle times during molding and higher strength and stiffness properties in a molded part. Certain nucleating agents can also improve the clarity and/or reduce the haze of a polypropylene part by producing crystalline aggregates known as spherulites. Such spherulites can be much smaller than the wavelength of visible light, leading to a reduction in light scattering that can result in haziness. These nucleating agents are typically either heterogeneous particles dispersed in molten polypropylene or compounds that dissolve in molten polypropylene and then crystallize out at temperatures higher than the temperature at which the polypropylene crystals start to develop.
  • Polypropylene can crystallize in one or more of three different crystalline forms known as the alpha, beta, and gamma forms.
  • the alpha phase is the most common and most stable form of polypropylene. Most conventional crystal nucleating agents nucleate only the alpha form of polypropylene.
  • the beta phase is less common and less thermodynamically stable, but beta crystalline polypropylene has been used to make novel products such as microporous oriented films. Beta phase polypropylene can also have higher ductility and impact strength than alpha phase polypropylene. Beta phase polypropylene has also been used to improve the properties of and lower the cost of making pressure pipe, thermoformed products, and geogrids that are used to reinforce roadbeds.
  • the gamma form of polypropylene does not have significant commercial interest.
  • Alpha nucleating agents are widely used to improve the physical properties and processing characteristics of polypropylene. These nucleating agents can initiate growth of alpha spherulites from molten polypropylene as it cools during the fabrication of molded or extruded parts. Such nucleation can accelerate the solidification process, leading to shorter cycle times and higher productivity. In addition, rapid formation of polymer crystals can lead to higher levels of crystallinity in a molded part. Also, properties that depend on the level of crystallinity, such as tensile strength and modulus, can also be higher in nucleated polypropylene. Another benefit of alpha nucleating agents is that by decreasing the size of the spherulites in the final molded or extruded part, the amount of light scattering can be decreased such that the final parts have improved clarity and reduced haze.
  • carboxylic acid metal salts such as sodium benzoate, lithium benzoate, aluminum 4-tertiary butyl benzoate, phosphate metal ester salts such as sodium bis (4-tertairy butyl phenyl) phosphate, or sodium 2,2'-methylenebis (4,6-di-tertiary butyl phenyl) phosphate and compounds such as polyalcohol derivatives (e.g. dibenzylidene sorbitol, bis (methyl benzylidene) sorbitol or bis (dimethyl benzylidene sorbitol).
  • carboxylic acid metal salts such as sodium benzoate, lithium benzoate, aluminum 4-tertiary butyl benzoate
  • phosphate metal ester salts such as sodium bis (4-tertairy butyl phenyl) phosphate, or sodium 2,2'-methylenebis (4,6-di-tertiary butyl phenyl) phosphate
  • compounds such as
  • the phosphate metal ester salts and the sorbitol based nucleants can be more powerful than inexpensive nucleants such as sodium benzoate and lithium benzoate.
  • the more powerful nucleants can provide more rapid crystallization, resulting in higher tensile strength, modulus, and better clarity compared to that of the less powerful alpha nucleants.
  • Sodium benzoate ( aBz) is the most commonly used alpha nucleant due to its low cost, but it does not provide ideal polypropylene parts.
  • the clarity of parts produced using NaBz can suffer from the relatively large particle size of NaBz and the difficulty of dispersing NaBz in molten polypropylene.
  • Both particle size and dispersibility can affect nucleation performance, since finer particle size can produce more nucleating particles at a given loading level of nucleant, and nucleation is a surface phenomenon that only takes place at the surface of the nucleating particle.
  • Sodium benzoate particles are somewhat sticky and tend to agglomerate, making it difficult to disperse and to feed pure NaBz into a compounding extruder.
  • this disclosure in one aspect, relates to nucleating agents, and specifically to crystal nucleating agents that can be used to produce, for example, polypropylene molded or extruded parts.
  • the present disclosure provides an alpha nucleated polypropylene resin comprising an alpha-nucleating agent produced by an in-situ reaction between a dispersed particle and a second chemical that dissolves in a molten polypropylene.
  • the present disclosure provides an alpha nucleated polypropylene resin, wherein the dispersed particle is non-nucleating.
  • the present disclosure provides an alpha nucleated polypropylene resin, wherein the dispersed particle comprises a metal salt, a metal oxide, or combination thereof.
  • the present disclosure provides an alpha nucleated polypropylene resin, wherein the dispersed particle comprises sodium carbonate, sodium bicarbonate, lithium carbonate, or a combination thereof.
  • the present disclosure provides an alpha nucleated polypropylene resin, wherein the second chemical comprises an organic mono- or dicarboxylic acid.
  • the present disclosure provides an alpha nucleated polypropylene resin, wherein the second chemical comprises benzoic acid.
  • the present disclosure provides an alpha nucleated polypropylene resin, wherein the polypropylene comprises a homopolymer, impact copolymer, random copolymer of polypropylene, or a combination thereof, where a co-monomer comprises ethylene, butene, octane, or a combination thereof.
  • the present disclosure provides an alpha nucleated polypropylene resin, wherein the dispersed particle has an average particle size less than about 10 micrometers. [0018] In another aspect, the present disclosure provides an alpha nucleated polypropylene resin, wherein a ratio of the dispersed particle to the second chemical is from about 2: 1 to about 200: 1.
  • the present disclosure provides an alpha nucleated polypropylene resin, wherein at least a portion of the surface of the dispersed particle reacts with the second chemical to produce an alpha nucleating salt which coats at least a portion of the surface of the dispersed particle.
  • the present disclosure provides a method for preparing a supported alpha nucleating agent, the method comprising contacting a dispersed particle and a second chemical in molten polypropylene.
  • the present disclosure provides a method for preparing a supported alpha nucleating agent, wherein a dispersed particle and a second chemical are contacted such that an in-situ reaction takes place between at least a portion of the surface of the dispersed particle and the second chemical to produce an alpha nucleant coating on the surface of the dispersed particle.
  • the present disclosure provides an alpha nucleated masterbatch that contains between 5% and 70% of a non-nucleating dispersed phase compound that has been reacted in-situ with a dissolved organic compound in the polypropylene melt such that the particles of the dispersed phase are coated with an alpha nucleating salt of the dispersed phase particle and the dissolved organic compound.
  • Ranges can be expressed herein as from “about” one particular value, and/or to "about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as "about” that particular value in addition to the value itself. For example, if the value "10” is disclosed, then “about 10" is also disclosed. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.
  • the terms “optional” or “optionally” means that the subsequently described event or circumstance can or can not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
  • the phrase “optionally substituted alkyl” means that the alkyl group can or can not be substituted and that the description includes both substituted and unsubstituted alkyl groups.
  • compositions of the invention Disclosed are the components to be used to prepare the compositions of the invention as well as the compositions themselves to be used within the methods disclosed herein. These and other materials are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these materials are disclosed that while specific reference of each various individual and collective combinations and permutation of these compounds can not be explicitly disclosed, each is specifically contemplated and described herein. For example, if a particular compound is disclosed and discussed and a number of modifications that can be made to a number of molecules including the compounds are discussed, specifically contemplated is each and every combination and permutation of the compound and the modifications that are possible unless specifically indicated to the contrary.
  • X and Y are present at a weight ratio of 2:5, and are present in such ratio regardless of whether additional components are contained in the compound.
  • a weight percent of a component is based on the total weight of the formulation or composition in which the component is included.
  • a residue of a chemical species refers to the moiety that is the resulting product of the chemical species in a particular reaction scheme or subsequent formulation or chemical product, regardless of whether the moiety is actually obtained from the chemical species.
  • an ethylene glycol residue in a polyester refers to one or more -OCH 2 CH 2 0- units in the polyester, regardless of whether ethylene glycol was used to prepare the polyester.
  • a sebacic acid residue in a polyester refers to one or more - CO(CH 2 ) 8 CO- moieties in the polyester, regardless of whether the residue is obtained by reacting sebacic acid or an ester thereof to obtain the polyester.
  • alkyl group as used herein is a branched or unbranched saturated
  • hydrocarbon group of 1 to 24 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, pentyl, hexyl, heptyl, octyl, decyl, tetradecyl, hexadecyl, eicosyl, tetracosyl and the like.
  • a "lower alkyl” group is an alkyl group containing from one to six carbon atoms.
  • alkoxy as used herein is an alkyl group bound through a single, terminal ether linkage; that is, an "alkoxy” group may be defined as -OR where R is alkyl as defined above.
  • a "lower alkoxy” group is an alkoxy group containing from one to six carbon atoms.
  • alkenyl group as used herein is a hydrocarbon group of from 2 to 24 carbon atoms and structural formula containing at least one carbon-carbon double bond.
  • alkynyl group as used herein is a hydrocarbon group of 2 to 24 carbon atoms and a structural formula containing at least one carbon-carbon triple bond.
  • aryl group as used herein is any carbon-based aromatic group including, but not limited to, benzene, naphthalene, etc.
  • aromatic also includes “heteroaryl group,” which is defined as an aromatic group that has at least one heteroatom incorporated within the ring of the aromatic group. Examples of heteroatoms include, but are not limited to, nitrogen, oxygen, sulfur, and phosphorus.
  • the aryl group can be substituted or unsubstituted.
  • the aryl group can be substituted with one or more groups including, but not limited to, alkyl, alkynyl, alkenyl, aryl, halide, nitro, amino, ester, ketone, aldehyde, hydroxy, carboxylic acid, or alkoxy.
  • cycloalkyl group is a non-aromatic carbon-based ring composed of at least three carbon atoms.
  • examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.
  • heterocycloalkyl group is a cycloalkyl group as defined above where at least one of the carbon atoms of the ring is substituted with a heteroatom such as, but not limited to, nitrogen, oxygen, sulphur, or phosphorus.
  • aralkyl as used herein is an aryl group having an alkyl, alkynyl, or alkenyl group as defined above attached to the aromatic group.
  • An example of an aralkyl group is a benzyl group.
  • hydroxyalkyl group as used herein is an alkyl, alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, halogenated alkyl, or heterocycloalkyl group described above that has at least one hydrogen atom substituted with a hydroxyl group.
  • alkoxyalkyl group is defined as an alkyl, alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, halogenated alkyl, or heterocycloalkyl group described above that has at least one hydrogen atom substituted with an alkoxy group described above.
  • esters as used herein is represented by the formula— C(0)OA, where A can be an alkyl, halogenated alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, or heterocycloalkenyl group described above.
  • carbonate group as used herein is represented by the formula -OC(0)OR, where R can be hydrogen, an alkyl, alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, halogenated alkyl, or heterocycloalkyl group described above.
  • aldehyde as used herein is represented by the formula -C(0)H.
  • keto group as used herein is represented by the formula -C(0)R, where R is an alkyl, alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, halogenated alkyl, or heterocycloalkyl group described above.
  • ether as used herein is represented by the formula AOAi, where A and Ai can be, independently, an alkyl, halogenated alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl, or heterocycloalkenyl group described above.
  • sulfo-oxo group as used herein is represented by the formulas -S(0) 2 R, - OS(0) 2 R, or , -OS(0) 2 0R, where R can be hydrogen, an alkyl, alkenyl, alkynyl, aryl, aralkyl, cycloalkyl, halogenated alkyl, or heterocycloalkyl group described above.
  • compositions disclosed herein have certain functions. Disclosed herein are certain structural requirements for performing the disclosed functions, and it is understood that there are a variety of structures that can perform the same function that are related to the disclosed structures, and that these structures will typically achieve the same result.
  • the present disclosure provides crystal nucleating agents that can, in various aspects, impart improved properties to a molded or extruded polypropylene part.
  • an improved sodium benzoate nucleant can be useful in a wide range of applications and reduce nucleant cost. It would also be advantageous to improve the nucleation efficiency of more expensive alpha nucleants so that they could be used at lower addition levels and reduce the final cost of a nucleated polypropylene part.
  • beta nucleation researchers have shown that by coating a nano-sized calcium carbonate particle with pimelic acid, it is possible to produce a supported calcium pimelate on the surface of the calcium carbonate particles.
  • Calcium pimelate is known to be a very effective beta-nucleating agent in polypropylene.
  • Such a supported beta nucleant can be produced using lower levels of expensive pimelic acid and can provide high activity and high selectivity for the beta nucleation of polypropylene.
  • This approach however, also has several drawbacks including the need for a difficult and expensive step of coating calcium carbonate particles with pimelic acid using solvents such as acetone.
  • nano-sized calcium carbonate should be prepared using precipitated calcium carbonate, which is much more expensive than the more commonly used ground calcium carbonate.
  • nano-particle size of these supported nucleating particles can lead to a low bulk density for the nucleating agent and difficulties in dispersing the nucleant in polypropylene.
  • the effectiveness of the calcium pimelate salt as a beta nucleant could be dramatically improved by producing the calcium pimelate in-situ in a polypropylene melt by incorporating both calcium carbonate and pimelic acid into the melt.
  • the pimelic acid can react, for example, at the surface of the calcium carbonate particles, to produce a coating of calcium pimelate which can function as a beta nucleant.
  • the calcium pimelate nucleant is supported on the calcium carbonate particles.
  • the required concentration of calcium pimelate can be reduced by at least a factor of 10, for example, a factor of at least 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, or 50.
  • the methods of the present invention can provide an improvement in nucleation ability as measured by the crystallization temperature, Tc, in the cooling cycle of a DSC scan (differential scanning calorimetry).
  • Tc crystallization temperature
  • the higher the Tc value the more rapid the crystallization of polypropylene.
  • Tc values are typically never higher than about 124 C, based on a DSC cooling rate of 10 °C per minute.
  • an in-situ generated calcium pimelate, as prepared in accordance with the various methods of the present disclosure can provide a Tc values of up to about 130 °C.
  • the methods of the present disclosure can be used to produce alpha nucleants in-situ, using a two-component system, so that the alpha nucleants are supported on non-nucleating particles.
  • the in-situ nucleants can be inexpensive and easy to disperse in molten polypropylene.
  • the support particles for the inventive alpha nucleants can comprise one or more inorganic salts, such as, for example, salts that are not soluble in molten polypropylene and/or which are easy to disperse in molten polypropylene to give small particles and uniform particle size dispersion.
  • the second component can be an an organic molecule, such as, for example, an organic acid, that is soluble in the molten polypropylene, and which can react with the support particles during, for example, standard extrusion compounding.
  • a dispersion of sodium bicarbonate and/or sodium carbonate in molten polypropylene, together with dissolved benzoic acid can be combined with benzoic acid.
  • a low level of benzoic acid and an excess of sodium bicarbonate can provide a coating of sodium benzoate on sodium
  • the dispersed particles can function as an alpha-nucleating agent.
  • the resulting dispersion of sodium benzoate coated particles of sodium bicarbonate can function as a strong alpha-nucleating agent. Since both sodium bicarbonate and benzoic acid are inexpensive components, this in-situ produced alpha nucleant can be inexpensive to produce.
  • lithium carbonate can be produced in-situ by blending an excess of lithium carbonate with benzoic acid into molten polypropylene, so that lithium benzoate forms on at least a portion of the surface of the dispersed lithium carbonate particles.
  • high performance alpha nucleating agents such as phosphate ester salts
  • phosphate ester salts can be produced by the in-situ reaction of a dissolved ester compound with a dispersed particle of an insoluble sodium salt in molten polypropylene.
  • the active nucleating agent would be present as a coating on the dispersed sodium salt particle.
  • Lower levels of active nucleating agent would be needed to achieve strong alpha nucleation in the polypropylene.
  • the present invention provides methods to produce a supported alpha nucleating in-situ by reacting an insoluble dispersed compound with a soluble compound in the molten polypropylene.
  • a chemical reaction can take place between the dissolved compound and the dispersed compound to produce an active alpha nucleating agent on at least a portion of the surface of the dispersed particle.
  • the dispersed particle can comprise sodium bicarbonate.
  • the dissolved compound can comprise benzoic acid.
  • the dispersed particle can comprise lithium carbonate and the dissolved compound can comprise benzoic acid.
  • an alpha nucleant can comprise a mixture of two or more individual alpha nucleants that can be formed, for example, in-situ.
  • a method for modifying at least a portion of the surface of dispersed, non-nucleating particles in a polypropylene matrix so that these particles become alpha nucleating agents.
  • Such a method comprises reacting the dispersed particles with a dissolved organic compound, such as benzoic acid, in the molten polypropylene so that a layer of an alpha nucleant salt, such as sodium benzoate and/or lithium benzoate, forms on the surface of the dispersed particles.
  • these salts are known to be effective alpha-nucleating agents, and since the dispersed particles are coated with these agents, the dispersed particles will become alpha-nucleating agents.
  • a further object of this invention is to provide articles that are molded or extruded from any of the alpha-nucleated polypropylene compositions described herein.
  • the efficiency of an alpha nucleant produced by the in-situ reaction of a dissolved organic compound such as benzoic acid with a metal salt such as sodium bicarbonate or lithium carbonate can be improved so that more rapid crystallization of the polypropylene part occurs when compared to that of simply dispersing the pure alpha nucleant in the polypropylene resin.
  • polypropylene that can be useful in the inventive compositions described herein can include polypropylene homopolymer and copolymers of propylene and ethylene, for example random and heterophasic (or impact) copolymers.
  • other polypropylene compositions can be used alone or in combination with any of the compositions recited herein.
  • the inventive polypropylene compositions can comprise one or more impact modifiers such as ethylene-propylene-diene monomer copolymers (EPDM), copolymers of ethylene with higher alpha-olefins (such as ethylene-octene copolymers), polybutadiene, polyisoprene, styrene-butadiene copolymers, hydrogenated styrene- butadiene copolymers, styrene-isoprene copolymers, and hydrogenated styrene-isoprene copolymers.
  • EPDM ethylene-propylene-diene monomer copolymers
  • copolymers of ethylene with higher alpha-olefins such as ethylene-octene copolymers
  • polybutadiene polyisoprene
  • styrene-butadiene copolymers polybutadiene
  • polyisoprene polyisoprene
  • inventive polypropylene compositions can further comprise polymer additives known in the art, including but not limited to hindered phenolic antioxidants, phosphorus based secondary antioxidants (e.g. phosphites and phosphonites), thioethers, hydroxylamines, nitrones, amine-N-oxides, alkylated diphenylamines, acid neutralizers (metal soaps, metal oxides, and the like as well as mixtures), metal deactivators, ultraviolet absorbers, hindered amine light stabilizers, benzoate light stabilizers, lubricants, anti-scratch additives, pigments, flame retardants, fluorescent whitening agents, and many others.
  • polymer additives known in the art, including but not limited to hindered phenolic antioxidants, phosphorus based secondary antioxidants (e.g. phosphites and phosphonites), thioethers, hydroxylamines, nitrones, amine-N-oxides, alkylated dipheny
  • additional polymer additives are described in "Plastic Additives Handbook", 5th ed., H. Zweifel, Ed., Hanser Publishers, Kunststoff, 2001, which is incorporated herein by reference.
  • the additional polymer additives may be incorporated into the polymeric materials as part of the additive mixtures of the present invention or as separate components.
  • various types of polypropylene-based resins can be used as the starting base resin.
  • the propylene-based polymers as referred to herein, contain at least one propylene unit.
  • the polymer may be a homopolymer of polypropylene, a random or block copolymer of propylene and another a-olefin or a mixture of a-olefins, or a blend of a polypropylene homopolymer and a different polyolefin.
  • the a-olefin may be polyethylene or an a-olefin having 4 to 12 carbon atoms.
  • the a-olefin contains containing 4 to 8 carbon atoms, such as butene-1 or hexene-1.
  • the copolymer may contain up to 40 mol%, and up to 50 mol%, of ethylene or an alpha- olefin having 4 to 12 carbon atoms, or mixtures thereof. Blends of propylene homopolymers with other polyolefins, such as high density polyethylene, low density polyethylene, or linear low density polyethylene and polybutylene can be used herein.
  • the propylene-based polymer has a melt flow rate (MFR) sufficiently high for facile and economical production of the injection molded or extruded parts, but not so high as to produce a molded part with undesirable physical properties.
  • MFR should be in the range of from about 0.5 decigrams/minute to about 200 decigrams/minute (dg/min), for example, about 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 25, 50, 75, 100, 125, 150, 175, or 200; or from about 2.0 dg/min to about 100 dg/min, for example, about 2, 3, 4, 5, 6, 7, 8, 9, 10, 13, 16, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85,
  • the MFR of the resin can exceed about 200 dg/min.
  • the molded part can become brittle or have reduced tensile strength.
  • the MFR is less than 0.5 dg/min, difficulties can be encountered in extruding or molding the part due to the high melt viscosity.
  • it can also be possible to blend polypropylene-based polymers of different melt flow rates to obtain a final average MFR that is in the desired range.
  • the propylene-based polymer is a polypropylene homopolymer or blend thereof.
  • the propylene-based polymer comprises polypropylene.
  • the propylene-based polymer comprises a random or block copolymer selected from the group consisting of copolymers of propylene and ethylene, copolymers of propylene an a-olefin with 4 to 12 carbon atoms, copolymers of polypropylene and a mixture of a-olefins with 4 to 12 carbon atoms, and copolymers of propylene and ethylene and one or more a-olefins with 4 to 12 carbon atoms.
  • the propylene-based polymer can optionally be admixed with one or more additives, including lubricants, antioxidants, ultraviolet absorbers, radiation resistance agents, antistatic agents, coupling agents, coloring agents, such as pigments and dyes, opacifiers, such as T1O2 and carbon black.
  • additives including lubricants, antioxidants, ultraviolet absorbers, radiation resistance agents, antistatic agents, coupling agents, coloring agents, such as pigments and dyes, opacifiers, such as T1O2 and carbon black.
  • standard quantities of the additives are included in the resin, although the addition of any minerals or abrasive additives should be kept to a minimum.
  • care should be taken to avoid incorporation of certain fatty acid salts or Group IIA metals such as calcium stearate, since these compounds can react with the alpha nucleating agents that have been formed in-situ, and destroy or diminish their alpha nucleating ability.
  • preparation of the inventive polypropylene compositions can be carried out by known methods such as dry blending of the components followed by mixing at a temperature sufficiently high to melt the thermoplastic components.
  • the melt blending can be carried out in any heatable container equipped with a mixer, e.g. in a closed apparatus such as an extruder, kneader, mixer or stirred vessel.
  • the second step of the mineral modification process can be conducted simultaneously to the preparation of the polypropylene compositions.
  • the insoluble metal salts or oxides can be contacted and/or mixed with an organic acid and polypropylene resin in an extruder at a temperature sufficient to melt the polypropylene.
  • composition is extruded as a strand, solidified in a water bath, and chopped into pellets suitable for use in subsequent molding processes.
  • sodium bicarbonate particles and/or lithium carbonate particles can be mixed with benzoic acid and polypropylene resin in an extruder. During this melt compounding process the benzoic acid can react in-situ with either the sodium bicarbonate or lithium carbonate to produce dispersed particles of the metal salts that are coated with the alpha-nucleating agents sodium benzoate and/or lithium benzoate.
  • useful articles molded from the inventive polypropylene compositions can be produced.
  • the pellets of the inventive alpha-nucleated polypropylene compositions can be fabricated into a number of useful articles, including automotive interior, exterior, and under- the-hood parts, appliance components, and many others.
  • the use of injection molding for the fabrication of such articles is an exemplary process and is well known in the art.
  • alpha-crystals can nucleate at the surface of the modified dispersed particles, producing a polypropylene article containing a fine grained alpha crystalline structure with a high crystallization temperature (Tc) as measured by DSC.
  • Tc crystallization temperature
  • the inventive articles are characterized by having a superior balance of tensile strength, stiffness, and reduced cycle time compared to articles prepared from comparable alpha-nucleated
  • thermal analysis through the use of Differential Scanning Calorimetry (DSC) can be performed on extruded pellets or molded parts of the inventive composition to assess the enhanced alpha nucleation that has been achieved through the use of in-situ formed alpha nucleating agents.
  • the parameter of most interest is the peak temperature of crystallization that is observed on the cooling scan after the sample is first heated in the DSC to a temperature that is well above the melting point of polypropylene.
  • a typical DSC cooling scan the molten polymer in the DSC is cooled at a controlled rate such as 10 degrees per minute.
  • Tc peak temperature
  • the methods of the present disclosure comprise the production of an alpha nucleating agent in-situ in molten polypropylene by reacting a dispersed phase comprising a metal salt, oxide, or other compound that does not melt or dissolve in polypropylene, with an organic compound that dissolves in polypropylene.
  • a metal salt, oxide, or other compound that does not melt or dissolve in polypropylene can include sodium bicarbonate and lithium carbonate.
  • An exemplary organic compound is benzoic acid.
  • the chemical reaction to produce this in-situ alpha nucleating agent can result in the alpha nucleant coating the dispersed particles of the insoluble metal salt.
  • the insoluble metal salt component can be present at an excess as compared to the dissolved organic compound.
  • the ratio of the dispersed salt to the dissolved organic compound can be in the range of from about 2: 1 to about 200: 1, for example, 2:1, 4:1, 6:1, 8:1, 10:1, 15:1, 20:1, 25:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, 125:1, 150:1, 175:1, or 200:1; or from about 5:1 to about 50:1, for example, 5:1, 7:1, 9:1, 11:1, 13:1, 15:1, 17:1, 19:1,21:1,23:1,25:1,27:1,29:1,31:1,33:1,35:1,37:1,39:1,41:1,43:1,45:1, 47:1,49:1, or 50:1.
  • the active alpha nucleant is present as a coating on at least a portion of the particle of the dispersed metal salt in the polypropylene, the nucleating efficiency of the alpha nucleant can be significantly improved, so that very low levels of the pure alpha nucleant are needed to produce high levels of alpha crystallinity in a molded polypropylene part, and very high crystallization temperatures (Tc) are achieved.
  • the dispersion of the alpha nucleant can be controlled by the particle size and/or particle size distribution of the dispersed metal salt.
  • the average particle size of a supported substrate can be less than about 10 micrometers, for example, less thab about 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 micrometers; or less than about 5 micrometers, for example, less than about 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, -.6, 0.5, 0.4, 0.3, 0.2, or 0.1 micrometers.
  • the dispersed metal salt and the organic compound can be directly blended with polypropylene using standard melt compounding equipment such as a twin screw extruder, a single screw extruder, or Farrell continuous mixer.
  • tt is not necessary to pre-coat the organic compound onto the surface of the supported substrate.
  • the organic compound can dissolve in the molten polypropylene during the melt compounding operation, and then react with the surface of the dispersed metal salt particles, producing a coating on the surface of this particle that represents the actual alpha nucleant.
  • the dispersed, coated particle can cause alpha crystals to form that then continue to grow until the fully crystallized polypropylene contains high concentrations of alpha crystals.
  • the metal salt particles can be coated with the organic compound during the grinding process that is used to produce the fine metal salt particle size.
  • such a pre- treatment step would eliminate the need to separately blend in the organic compound and the metal salt with polypropylene during the compounding process.
  • a masterbatch of the dispersed, coated alpha nucleating particles of the dispersed metal salt by using high concentrations of the metal salt and high concentrations of the organic compound during the melt compounding operation.
  • Such a masterbatch can contain a high concentration of coated particles, such that it can be greatly diluted by subsequent blending of small quantities of this masterbatch with large quantities of polypropylene in order to produce an alpha nucleated polypropylene exhibiting high Tc vales in the DSC and short cycle times during injection molding.
  • samples of sodium benzoate nucleated polypropylene were prepared.
  • a comparative sodium benzoate nucleated polypropylene sample identified as 004-14-4 in Table 1 was prepared by first making a masterbatch containing 10 % sodium benzoate (NaBz) in 90 % polypropylene homopolymer having a melt flow rate of 12 g/10 minutes. This masterbatch was prepared using a co-rotating twin screw extruder at a melt temperature of about 230 °C.
  • Portions of each plaque were subjected to analysis by DSC, operating under a nitrogen purge and using heating and cooling rates of 10 °C per minute.
  • the first heat scan started at room temperature and ran to 230 °C, followed by a cool down to room temperature and a second heating to 230 °C.
  • the crystallization temperature, Tc was measured as the peak temperature of the exotherm observed on the cool down scan.
  • polypropylene sames were prepared using lithium benzoate or a combination of lithium carbonate and benzoic acid. These samples were prepared by blending either lithium benzoate (LiBz) or a combination of lithium carbonate plus benzoic acid with polypropylene using a 2-roll mill under the same conditions as described above for Example 1. The compositions of the blends and the Tc values are shown in Table 2 below:
  • nucleated polypropylene samples were prepared using a 1" single screw extruder.
  • the sodium benzoate (NaBz) containing samples were prepared by blending pure sodium benzoate, available from Sigma Aldridge or Adeka Palmarole Company, with a polypropylene reactor powder resin using an addition level of 0.12 %.
  • the sodium benzoate was first ground to a fine powder using a mortar and pestle.
  • the Adeka Palmarole sodium benzoate, identified as NA-08 was already in the form of a fine powder so it was used without further treatment.
  • nucleated polypropylene samples were prepared using a 1" single screw extruder.
  • Lithium benzoate (LiBz) containing samples were prepared by blending pure lithium benzoate, available from either Sigma Aldridge or Adeka Palmarole Company, with a polypropylene reactor powder resin using an addition level of 0.12 %.
  • the lithium benzoate was first ground to a fine powder using a mortar and pestle.
  • the Adeka Palmarole lithium benzoate was already in the form of a fine powder so it was used withought further treatment.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

La présente invention a pour objet des procédés de production d'agents d'alpha-nucléation à bas coût in-situ dans un polypropylène fondu par la réaction de particules d'un sel ou d'un oxyde métallique en phase dispersée non nucléante insoluble avec un composé organique soluble, le produit réactif de ces deux composants étant un agent d'alpha-nucléation qui enrobe les particules en phase dispersée. Les agents d'alpha-nucléation peuvent être des agents d'alpha-nucléation produits in-situ. Des articles en polypropylène ayant des niveaux supérieurs de cristallinité peuvent être préparés à l'aide d'agents de nucléation classiques.
PCT/US2012/025037 2011-02-14 2012-02-14 Agent de nucléation cristallin supporté pour polypropylène WO2012112542A1 (fr)

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US20160137761A1 (en) * 2013-06-19 2016-05-19 Borealis Ag Process for production of polypropylene with high polydispersity
EP3109274A1 (fr) 2015-06-23 2016-12-28 Omya International AG Surface traitée produit matériau de remplissage pour alpha-nucléation de polyoléfines
CN116769253A (zh) * 2023-08-24 2023-09-19 山东路德新材料股份有限公司 一种土工格栅改性聚丙烯工程塑料及其制备方法与应用

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US6313204B1 (en) * 1997-01-17 2001-11-06 New Japan Chemical Co., Ltd. Method for recrystallizing diacetal in polyolefin resin
US20080045638A1 (en) * 2002-08-12 2008-02-21 Chapman Bryan R Plasticized hetero-phase polyolefin blends
US20080249248A1 (en) * 2007-04-09 2008-10-09 Derek Thurman Isotactic Polypropylene Nucleation
US20090081387A1 (en) * 2005-09-13 2009-03-26 Fujifilm Corporation Method of Producing Cyclic Polyolefin Film, Cyclic Polyolefin Film Produced by the Production Method, Method of Preparing Liquid Dispersion of Fine Particles, Liquid Dispersion of Fine Particles and Method of Preparing Dope
US20100016491A1 (en) * 2006-12-19 2010-01-21 New Japan Chemical Co., Ltd. Novel polyolefin resin composition and molded resin obtained therefrom

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Publication number Priority date Publication date Assignee Title
US6313204B1 (en) * 1997-01-17 2001-11-06 New Japan Chemical Co., Ltd. Method for recrystallizing diacetal in polyolefin resin
US20080045638A1 (en) * 2002-08-12 2008-02-21 Chapman Bryan R Plasticized hetero-phase polyolefin blends
US20090081387A1 (en) * 2005-09-13 2009-03-26 Fujifilm Corporation Method of Producing Cyclic Polyolefin Film, Cyclic Polyolefin Film Produced by the Production Method, Method of Preparing Liquid Dispersion of Fine Particles, Liquid Dispersion of Fine Particles and Method of Preparing Dope
US20100016491A1 (en) * 2006-12-19 2010-01-21 New Japan Chemical Co., Ltd. Novel polyolefin resin composition and molded resin obtained therefrom
US20080249248A1 (en) * 2007-04-09 2008-10-09 Derek Thurman Isotactic Polypropylene Nucleation

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160137761A1 (en) * 2013-06-19 2016-05-19 Borealis Ag Process for production of polypropylene with high polydispersity
EP3109274A1 (fr) 2015-06-23 2016-12-28 Omya International AG Surface traitée produit matériau de remplissage pour alpha-nucléation de polyoléfines
US10654986B2 (en) 2015-06-23 2020-05-19 Omya International Ag Surface treated filler material product for alpha-nucleation of polyolefins
CN116769253A (zh) * 2023-08-24 2023-09-19 山东路德新材料股份有限公司 一种土工格栅改性聚丙烯工程塑料及其制备方法与应用
CN116769253B (zh) * 2023-08-24 2023-12-12 山东路德新材料股份有限公司 一种土工格栅改性聚丙烯工程塑料及其制备方法与应用

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