Classifications

• • 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
  • C08K5/098—Metal salts of carboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C61/00—Compounds having carboxyl groups bound to carbon atoms of rings other than six-membered aromatic rings
  • C07C61/12—Saturated polycyclic compounds
  • C07C61/125—Saturated polycyclic compounds having a carboxyl group bound to a condensed ring system
  • C07C61/13—Saturated polycyclic compounds having a carboxyl group bound to a condensed ring system having two rings
• • 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
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2602/00—Systems containing two condensed rings
  • C07C2602/36—Systems containing two condensed rings the rings having more than two atoms in common
  • C07C2602/42—Systems containing two condensed rings the rings having more than two atoms in common the bicyclo ring system containing seven carbon atoms

Definitions

• This invention relates to types of bicyclic nucleator compounds that provide highly versatile nucleation benefits for different thermoplastics.
• Such nucleator compounds provide very high peak crystallization temperatures and short crystallization cycle time for certain thermoplastic formulations with or without the presence of other calcium stearate and/or peroxide components within the same type of formulation.
• inventive nucleator compounds exhibit very little, if any, fugitivity from such thermoplastic formulations thereby providing excellent processing characteristics as well as excellent nucleation capabilities for a variety of different thermoplastic resins, independent of the presence of different, potentially necessary, additives (such as calcium stearate).
• Thermoplastic compositions as well as thermoplastic additive packages comprising such inventive nucleator compounds are also contemplated within this invention.
• thermoplastic is intended to mean a polymeric material that will melt upon exposure to sufficient heat but will retain its solidified state, but not prior shape without use of a mold or like article, upon sufficient cooling. Specifically, as well, such a term is intended solely to encompass polymers meeting such a broad definition that also exhibit either crystalline or semi-crystalline morphology upon cooling after melt- formation. Particular types of polymers contemplated within such a definition include, without limitation, polyolefins (such as polyethylene, polypropylene, polybutylene, and any combination thereof), polyamides (such as nylon), polyurethanes, polyesters (such as polyethylene terephthalate), and the like (as well as any combinations thereof).
• Thermoplastics have been utilized in a variety of end-use applications, including storage containers, medical devices, food packages, plastic tubes and pipes, shelving units, and the like. Such base compositions, however, must exhibit certain physical characteristics in order to permit widespread use. Specifically within polyolefins, for example, uniformity in arrangement of crystals upon crystallization is a necessity to provide an effective, durable, and versatile polyolefin article. In order to achieve such desirable physical properties, it has been known that certain compounds and compositions provide nucleation sites for polyolefin crystal growth during molding or fabrication. Generally, compositions containing such nucleating compounds crystallize at a much faster rate than unnucleated polyolefin. Such crystallization at higher temperatures results in reduced fabrication cycle times and a variety of improvements in physical properties, such as, as one example, stiffness.
• nucleators Such compounds and compositions that provide faster and or higher polymer crystallization temperatures are thus popularly known as nucleators.
• Such compounds are, as their name suggests, utilized to provide nucleation sites for crystal growth during cooling of a thermoplastic molten formulation. Generally, the presence of such nucleation sites results in a larger number of smaller crystals. As a result of the smaller crystals formed therein, clarification of the target thermoplastic may also be achieved, although excellent clarity is not always a result. The more uniform, and preferably smaller, the crystal size, the less light is scattered. In such a manner, the clarity of the thermoplastic article itself can be improved.
• thermoplastic nucleator compounds are very important to the thermoplastic industry in order to provide enhanced clarity, physical properties and/or faster processing.
• dibenzylidene sorbitol derivative compounds are typical nucleator compounds, particularly for polypropylene end-products.
• NA-11 sodium 2,2' -methyl ene-bis-(4,6-di-tert- butylphenyl) phosphate
• NA-11 aluminum bis[2,2'-methylene-bis-(4,6-di-tert-butylphenyl)phosphate]
• NA-21 aluminum bis[2,2'-methylene-bis-(4,6-di-tert-butylphenyl)phosphate]
• talc talc, and the like.
• Such compounds all impart high polyolefin crystallization temperatures; however, each also exhibits its own drawback for large-scale industrial applications.
• acetals of sorbitol and xylitol are typical nucleators for polyolefins and other thermoplastics as well.
• Dibenzylidene sorbitol (DBS) was first disclosed in U.S. Pat. No. 4,016,118 by Hamada, et al. as effective nucleating and clarifying agents for polyolefin. Since then, large numbers of acetals of sorbitol and xylitol have been disclosed, including bis(p -methylbenzylidene) sorbitol (hereinafter referred to as 4-MDBS). Representative references of such other compounds include Mahaffey, Jr., U.S. Pat. No. 4,371,645 [di-acetals of sorbitol having at least one chlorine or bromine substituent] .
• the effective nucleating agents are the metal salts of organic acids. Wijga in U.S. Pat. Nos. 3,207,735, 3,207,736, and 3,207,738, and Wales in
• nucleating agents Another class of nucleating agents was suggested by Nakahara, et al. in U.S. Pat. No. 4,463,113, in which cyclic bis-phenol phosphates was disclosed as nucleating and clarifying agents for polyolefin resins, as well as U.S. Pat. No. 5,342,868 to Kimura, et al. Compounds that are based upon these technologies are marketed under the trade names NA-11 and NA- 21, discussed above.
• bicyclic compounds such as bicyclic dicarboxylic acid and salts
• polyolefin nucleating agents as well within Patent Cooperation Treaty Application WO 98/29494, 98/29495 and 98/29496, all assigned to Minnesota Mining and Manufacturing.
• the best working examples of this technology are embodied in disodium bicyclo[2.2.1]heptene dicarboxylate and camphanic acid.
• the efficacy of nucleating agents is typically measured by the peak crystallization temperature of the polymer compositions containing such nucleating agents.
• a high polymer peak crystallization is indicative of high nucleation efficacy, which generally translates into fast processing cycle time and more desirable physical properties, such as stiffness/impact balance, etc., for the fabricated parts.
• Compounds mentioned above all impart relatively high polyolefin crystallization temperatures; however, each also exhibits its own drawback for large-scale industrial applications.
• the effective nucleating compounds exhibit a very high peak crystallization temperature, for example, above 125°C within a test homopolymer polypropylene that, when unnucleated exhibits a number of different characteristics such as a density of about 0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (R scale) of about 90, a tensile strength of about 4,931 psi, an elongation at yield of about 10%, a flexural modulus of about 203 ksi, an Izod impact strength of about
• a very high peak crystallization temperature for example, above 125°C within a test homopolymer polypropylene that, when unnucleated exhibits a number of different characteristics such as a density of about 0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (R scale) of about 90, a tensile strength of about 4,931 psi, an
• Such a polypropylene homopolymer provides an effective test subject for this purpose due to the general uniformity of product available (and thus better uniformity in peak crystallization temperature, etc., results, therein for samples of such a thermoplastic), as well as the widespread use of such a thermoplastic.
• a test homopolymer is not the only thermoplastic in which the inventive nucleating agent may be present; it is solely a test formulation in order to determine the highest peak crystallization temperature, etc., for certain inventive nucleating agents under certain conditions.
• camphanic acid exhibits such a high polymer peak crystallization temperature within such a test homopolymer propylene formulation.
• camphanic acid exhibits very poor thermal stability, where it tends to vaporize and accumulate on the surface of plastic processing equipments during processing. This phenomenon is generally referred to as "plate out” within the plastics industry. The "plate out” effect of this additive make it impractical for any commercial use.
• the combination of very high polymer peak crystallization temperature (thus highly efficient nucleation) and a low degree of fugitivity (and thus high thermal stability and low plate-out characteristics) within the target polymers is very desirable within the plastics industry, particularly where the peak crystallization temperature is measured above 126°C within a homopolymer polypropylene measured by differential scanning calorimetry at a rate of 20°C/minute. So far, such a combination has not been provided within this intensively studied area of polymer nucleating agents.
• nucleator compounds such as sodium benzoate, NA-1 1, disodium bicyclo[2.2.1] heptene dicarboxylate
• nucleator compounds are generally provided in powder or granular form to the polyolefin manufacturer, and since uniform small particles of nucleating agents are imperative to provide the requisite uniform dispersion and performance, such compounds must remain as small particles through storage.
• Certain nucleators such as sodium benzoate, exhibit high degrees of hygroscopicity such that the powders made therefrom hydrate easily resulting in particulate agglomeration.
• Such agglomerated particles may require further milling or other processing for deagglomeration in order to achieve the desired uniform dispersion within the target thermoplastic.
• unwanted agglomeration due to hydration may also cause feeding and/or handling problems for the user.
• Some nucleating agents such as certain DBS derivatives, exhibit certain practical deficiencies such as a tendency to plate-out at high processing temperatures.
• DBS derivatives particularly where the aromatic rings are mono-substituted, show much improved thermal stability.
• such compounds also tend to exhibit undesirable migratory properties coupled with problematic organoleptic deficiencies within certain polyolefin articles. As a result, such compounds cannot be widely utilized in some important areas, such as within medical devices (e.g., syringes, and the like) and food packaging.
• an object of the invention is to provide a polyolefin nucleating agent that provides excellent high peak crystallization temperatures to polypropylene articles and formulations and also exhibits extremely low fugitivity (excellent thermal stability, low plate- out).
• a further object of the invention is to provide a nucleator compound and compositions thereof that exhibit excellent calcium stearate compatibility within target polyolefin articles and formulations.
• the inventive compounds must exhibit excellent low hygroscopicity in order to accord an extremely good shelf-stable additive composition.
• Another objective of this invention is to provide a nucleating compound and composition that exhibits low migration once incorporated within polyolefin articles.
• Another objective of this invention is to provide a nucleating agent and composition that exhibits little or no foul taste and/or odor within polyolefin articles.
• Another object of the invention is to provide a nucleator compound that affects the crystallization process within the target polyolefin polymer in such a manner that the resultant lamellar structure is highly unique (extremely thick) in comparison with other nucleated polypropylene articles and formulations such that said polyolefin exhibits very high stiffness properties.
• this invention encompasses a nucleating agent which induces a peak crystallization temperature of at least 125°C (preferably, at least 125.5; more preferably, at least 126; still more preferably, at least 126.5; and most preferably at least 127; preferably such a temperature is as high as possible, up to the level of a self-nucleated test homopolymer polypropylene resin, such as at about 137-8°C, with a high temperature of about 134°C most preferred) for a test homopolymer polypropylene formulation, wherein the unnucleated test homopolymer propylene exhibits a density of about 0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (R scale) of about 90, a tensile strength of about 4,931 psi, an elongation at yield of about 10%, a flexural modulus of about 203 ksi, an Izod impact strength of about 0.67 ft
• a nucleating agent which induces a crystallization half time (tj /2 ) of at most 2.0 minutes in a test homopolymer polypropylene formulation, wherein the unnucleated test homopolymer propylene exhibits a density of about 0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (R scale) of about 90, a tensile strength of about 4,931 psi, an elongation at yield of about 10%, a flexural modulus of about 203 ksi, an Izod impact strength of about 0.67 ft-lb/in, and a deflection temperature at 0.46 mPa of about 93°C, and wherein said formulation is extruded then molded into plaques having dimensions of about 51 mm X 76 mm X 1.27 mm, wherein said tj /2 is measured by differential scanning calorimetry at a constant crystallization temperature of about
• this invention also encompasses a nucleating agent which induces a standard peak crystallization temperature of at least 123.5°C in a test homopolymer polypropylene formulation, wherein the unnucleated test homopolymer polypropylene exhibits a density of about 0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness
• nucleating agent is present in at most 1500 ppm, wherein said polymer nucleator exhibits no appreciable fugitivity from said polypropylene formulation during compounding of said polypropylene, and wherein said nucleating agent induces said peak crystallization temperature in said polypropylene formulation when no calcium stearate is present, and wherein said nucleating agent induces a comparative peak crystallization temperature of at most 2°C lower than said standard peak crystallization for the same polypropylene formulation when at least 800 ppm of calcium stearate is present. Furthermore, such a compound exhibits a very low hygroscopicity as well.
• this invention encompasses a nucleating agent which produces an effective nucleation density of greater than 7 X 10 9 nuclei/cm 3 at an isothermal crystallization temperature of about 148°C in a test homopolymer polypropylene formulation comprising said nucleating agent, wherein the unnucleated test homopolymer propylene exhibits a density of about 0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (R scale) of about 90, a tensile strength of about 4,931 psi, an elongation at yield of about 10%, a flexural modulus of about 203 ksi, an Izod impact strength of about 0.67 ft-lb/in, and a deflection temperature at 0.46 mPa of about 93°, and wherein said formulation is extruded then molded into plaques having dimensions of about 51 mm X 76 mm X 1.27 mm, and wherein said nucle
• nucleating agent which exhibits a nucleation effectiveness factor (NEF) of greater than 0.06 in a test homopolymer polypropylene formulation having a density of about 0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (R scale) of about 90, a tensile strength of about 4,931 psi, an elongation at yield of about 10%, a flexural modulus of about 203 ksi, an Izod impact strength of about 0.67 ft-lb/in, and a deflection temperature of 0.46 mPa at about 93 °C, wherein said formulation is extruded and then molded into plaques having dimensions of about 51 mm X 76 mm X 1.27 mm.
• NEF nucleation effectiveness factor
• inventive nucleating agent is defined above as performing to a certain degree within a test polymer formulation, and is not required to be a component within such a test polymer formulation.
• inventive nucleating agent must perform to a certain level within a test homopolymer propylene, it may be present within any other type of polymer (such as a thermoplastic), including blends of polymers.
• a thermoplastic such as a thermoplastic
• the particular polymers within which such an inventive nucleating is effective and useful are listed below in greater detail.
• the bicyclic compounds are defined as organic compounds that contain two or more rings wherein at least two of the said rings share at least two nonadjacent atoms.
• novel nucleator compounds include the metal or organic salts of saturated [2.2.1] bicyclic dicarboxylates, and most preferably of these types of compounds conforming to Formula (I)
• Mj and M 2 are the same or different and are independently selected from the group consisting of metal or organic cations, and Rj, R 2 , R 3 , R , R5, 6 , R7, R 8 , 9, and RJO are individually selected from the group consisting of hydrogen, C 1 -C9 alkyl, hydroxyl, C 1 -C 9 alkoxy, C 1 -C 9 alkyleneoxy, amine, and C 1 -C 9 alkylamine, halogen, phenyl, alkylphenyl, and geminal or vicinal C 1 -C 9 carbocyclic.
• the metal cations are selected from the group consisting of calcium, strontium, barium, magnesium, aluminum, silver, sodium, lithium, rubidium, potassium, and the like.
• group I and group II metal ions are generally preferred.
• group I and II cations sodium, potassium, calcium and strontium are preferred, wherein sodium and calcium are most preferred.
• the Mj and M 2 groups may also be combined to form a single metal cation (such as calcium, strontium, barium, magnesium, aluminum, and the like).
• this invention encompasses all stereochemical configurations of such compounds, the cis configuration is preferred wherein cis-endo is the most preferred embodiment.
• polyolefin articles and additive compositions for polyolefin formulations comprising at least one of such compounds are also encompassed within this invention.
• nucleators which exhibit very high heat stabilities (and thus very low plate-out) within test polypropylene formulations. Therefore, a weight loss of nucleator compound during a thermal stability test of at most 5% is encompassed within this term.
• inventive nucleating agents meet all of these important requirements very well.
• inventive salts provide excellent high peak crystallization temperatures in a variety of polyolefin formulations, particularly within random copolymer polypropylene (hereinafter RCP) and homopolymer polypropylene (hereinafter HP).
• RCP random copolymer polypropylene
• HP homopolymer polypropylene
• inventive salts provide excellent mechanical properties for polyolefin articles without the need for extra fillers and rigidifying additives, and desirable processing characteristics such as improved (shorter) cycle time.
• the salts also show much improved hygroscopicity comparing to prior art and thus granular or powder formulations of such a salt do not agglomerate or clump together. Lastly, such inventive salts do not interact deleteriously with calcium stearate additives.
• the WO 98/29494 reference discloses nucleation and clarification additives for polyolefin articles including unsaturated [2.2.1] dicarboxylate salts; however, there is no exemplification of a saturated dicarboxylate salt of this type.
• the closest embodiment within that art is identified as disodium bicyclo[2.2.1]heptene dicarboxylate.
• the peak crystallization temperatures provided target polyolefin articles with these inventive saturated compounds are from about 2.5 to about 5°C above that for the related unsaturated compounds.
• Such dramatic improvements are simply unexpected and are unpredictable from any known empirical or theoretical considerations.
• significant improvements in hygroscopicity of the saturated compounds were also unexpectedly observed. Such unpredictable improvements are of great practical significance as discussed before.
• inventive salts are thus added within the target polyolefin in an amount from about 50 ppm to about 20,000 ppm by weight in order to provide the aforementioned beneficial characteristics, most preferably from about 200 to about 4000 ppm. Higher levels, e.g., 50%) or more by weight, may also be used in a masterbatch formulation.
• Optional additives within the inventive salt-containing composition, or within the final polyolefin article made therewith, may include plasticizers, antistatic agents, stabilizers, ultraviolet absorbers, and other similar standard polyolefin thermoplastic additives.
• polyolefin or polyolefin resin is intended to encompass any materials comprised of at least one polyolefin compound.
• Preferred examples include isotactic and syndiotactic polypropylene, polyethylene, poly(4-methyl)pentene, polybutylene, and any blends or copolymers thereof, whether high or low density in composition.
• the polyolefin polymers of the present invention may include aliphatic polyolefins and copolymers made from at least one aliphatic olefin and one or more ethylenically unsaturated co-monomers.
• the co-monomers if present, will be provided in a minor amount, e.g., about 10 percent or less or even about 5 percent or less, based upon the weight of the polyolefin (e.g. random copolymer polypropylene), but copolymers containing up to 25% or more of the co- monomer (e.g., impact copolymers) are also envisaged.
• Other polymers or rubber such as EPDM or EPR
• Such co-monomers may serve to assist in clarity improvement of the polyolefin, or they may function to improve other properties of the polymer.
• Other examples include acrylic acid and vinyl acetate, etc.
• olefin polymers whose transparency can be improved conveniently according to the present invention are polymers and copolymers of aliphatic monoolefins containing 2 to about 6 carbon atoms which have an average molecular weight of from about 10,000 to about 2,000,000, preferably from about 30,000 to about 300,000, such as, without limitation, polyethylene, linear low density polyethylene, isotactic polypropylene, syndiotactic polypropylene, crystalline ethylene propylene copolymer, poly(l-butene), polymethylpentene, 1-hexene, 1-octene, and vinyl cyclohexane.
• the polyolefins of the present invention may be described as basically linear, regular polymers that may optionally contain side chains such as are found, for instance, in conventional low density polyethylene.
• the nucleating agents of the present invention are not restricted to polyolefins, and may also give beneficial nucleation properties to polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), as well as polyamides such as Nylon 6, Nylon 6,6, and others.
• PET polyethylene terephthalate
• PBT polybutylene terephthalate
• PEN polyethylene naphthalate
• any thermoplastic composition having some crystalline content may be improved with the nucleating agents of the present invention.
• the compositions of the present invention may be obtained by adding the inventive saturated bicyclic dicarboxylic salt (or combination of salts or composition comprising such salts) to the thermoplastic polymer or copolymer and merely mixing the resultant composition by any suitable means.
• inventive compositions may be present in any type of standard thermoplastic (e.g., polyolefin, most preferably) additive form, including, without limitation, powder, prill, agglomerate, liquid suspension, and the like, particularly comprising dispersion aids such as polyolefin (e.g., polyethylene) waxes, stearate esters of glycerin, montan waxes, mineral oil, and the like.
• any form may be exhibited by such a combination or composition including such combination made from blending, agglomeration, compaction, and/or extrusion.
• composition may then be processed and fabricated by any number of different techniques, including, without limitation, injection molding, injection blow molding, injection stretch blow molding, injection rotational molding, extrusion, extrusion blow molding, sheet extrusion, film extrusion, cast film extrusion, foam extrusion, thermoforming (such as into films, blown-films, biaxially oriented films), thin wall injection molding, and the like into a fabricated article.
• injection molding injection blow molding, injection stretch blow molding, injection rotational molding, extrusion, extrusion blow molding, sheet extrusion, film extrusion, cast film extrusion, foam extrusion, thermoforming (such as into films, blown-films, biaxially oriented films), thin wall injection molding, and the like into a fabricated article.
• Thermoplastic compositions were produced comprising the additives from the Examples above and sample homopolymer polypropylene (HP) resin plaques, produced dry blended in a Welex mixer at -2000 rpm, extruded through a single screw extruder at 400- 450° F, and pelletized. Accordingly, one kilogram batches of target polypropylene were produced in accordance with the following table: HOMOPOLYMER POLYPROPYLENE COMPOSITION
• Polypropylene homopolymer (Himont Pro fax® 6301) 1000 g
• Irganox® 1010 Primary Antioxidant (from Ciba) 500 ppm Irgafos® 168, Secondary Antioxidant (from Ciba) 1000 ppm
• the base HP [having a density of about 0.9 g/cc, a melt flow of about 12 g/10 min, a Rockwell Hardness (R scale) of about 90, a tensile strength of about 4,931 psi, an elongation at yield of about 10%, a flexural modulus of about 203 ksi, an Izod impact strength of about 0.67 ft-lb/in, and a deflection temperature at 0.46 mPa of about 93°C, as well as an expected isotacticity of between about 96 and 99% through xylene solubles analysis] and all additives were weighed and then blended in a Welex mixer for 1 minute at about 1600 rpm.
• the molder was set at a temperature anywhere between 190 and 260°C, with a range of 190 to 240°C preferred, most preferably from about 200 to 230°C and at an injection speed within the range of between about 1 and about 5 cm 3 /second.
• the plaques had dimensions of about 51 mm X 76 mm X 1.27 mm, and the mold had a mirror finish which was transferred to the individual plaques.
• the mold cooling circulating water was controlled at a temperature of about 25°C.
• plaques of clarified polypropylene thermoplastic resin were formed through the process outlined above with the specific compositions listed above in the above Table. These plaque formulations are, of course, merely preferred embodiments of the inventive article and method and are not intended to limit the scope of this invention.
• the resultant plaques were then tested for peak crystallization temperatures (by Differential Scanning Calorimetry). Crystallization is important in order to determine the time needed to form a solid article from the molten polyolefin composition.
• a polyolefin such as polypropylene has a crystallization temperature of about 110°C at a cooling rate of 20°C/min.
• the best nucleator compound added will invariably also provide the highest crystallization temperature for the final polyolefin product.
• the nucleation composition efficacy was evaluated by using a modified differential scanning procedure based upon the test protocol ASTM D3417-99 wherein the heating and cooling rates utilized have been altered to 20°C/minute each.
• T c polymer peak crystallization temperature
• Thermal stability of is an important criteria for polymer additives. Additives lacking thermal stability would cause plate out and other processing issues. Stability tests are conducted on a Thermogravimetric Analyzer from TA Instruments. Roughly 10 mg of dry sample is added to the stainless steel sample cell. The sample cell is then blanketed with nitrogen. Sample is allowed to equilibrate for 5 minutes at 25°C. The temperature is then raised at 20°C/min ramp rate until it reaches 500°C. Weight loss in percentage versus temperature is recorded for the sample nucleator from within the sample polypropylene as a result of such thermal stability testing.
• Polypropylene is typically processed between 200- 250°C and a weight loss of the sample nucleator in excess of 5% at 250°C is generally considered as unsuitable for use since the remaining amounts would be insufficient for proper and necessary nucleation to occur.
• the weight loss data for camphanic acid and disodium [2.2.1]cycloheptane dicarboxylate is shown below:
• camphanic acid exhibits comparable polymer peak crystallization temperature, it lacks the necessary thermal stability for practical commercial use.
• nucleators were tested in formulations with and without calcium stearate.
• the nucleation efficacy of the nucleators in each formulation was studied by measuring polymer crystallization temperature.
• the formulations and testing conditions are identical with those discussed above. A drop of 2 °C or more is considered a failure.
• Example C 184 Example A 194
• the inventive saturated compound exhibited much improved nucleation of polyester over the control with no nucleator compound and the unsaturated nucleator compound.
• Seven plaques were cut into nine strips each to give a total surface area of approximately 600 cm . These strips were rinsed with deionized water and allowed to dry. They were then placed into a glass extraction vessel and covered with 200 ml of deionized water. The glass vessels and their contents were autoclaved for 60 minutes at 121 ° C, and were allowed to cool and settle for 24 hours. After settling, approximately 60 ml of the extraction solution was transferred to a clean beaker, and 10 ml of this solution was filtered through a 0.8-®m filter fitted to a syringe. The filtrate was collected in a 1-cm quartz cuvette.
• thermoplastic product for different types of end-uses.
• Example 1 shows extraction levels comparable to thermoplastic samples containing no nucleator at all and thus indicates that such thermoplastic may be useful for various end-uses.
• One method of evaluating the nucleating efficiency of a nucleating agent in a given resin is to calculate the density of nucleating sites per unit volume of polymer as well as comparing such density measurements at differing isothermal crystallization temperatures.
• the effective nucleation densities for the inventive and comparative nucleating agents were calculated by combining isothermal crystallization kinetic data measured using differential scanning calorimetry and spherulitic growth rate data measured with optical microscopy.
• a Perkin Elmer DSC-7 was calibrated with an indium metal standard at a heating rate of 20C/min. Polymer samples with a thickness of 250 +/- 50 microns and a weight of 5.0 +/- 0.5 mg were encased in aluminum pans. The pans were then heated from 60°C to 220°C at 20°C/min, held 2 minutes, rapidly cooled to the isothermal crystallization temperature, and then held at the isothermal crystallization temperature until the crystallization was complete.
• For example, at an isothermal crystallization temperature of 140°C, homopolymer polypropylene nucleated with 0.1 % NA-1 lUF had Avrami rate constants n 3.21 and K
• the following Table shows the nucleation density measurements for various nucleating agents at 140 and 148°C isotherms. An asterisk for NA-21 indicates that the nucleation density was too low to be measured.
• the inventive nucleating agent provided an increase in nucleation density within the test homopolymer polypropylene at least an order of magnitude greater than the closest typical polyolefin nucleating agents. Therefore, such an inventive nucleating agent is defined as one which, at an isothermal T c of about 148°C of at least 7 E 9 (7 X 10 9 ) nuc/cm 2 ; preferably at least 1 E 10; still more preferably, at least 5 E 10; and most preferably at least 1 E l l, within the test homopolymer polypropylene formulation as noted above, and which, as noted above, does not exhibit any appreciable fugitivity from the thermoplastic formulation during compounding thereof.
• NEF nucleation effectiveness factor
• NEF N(148°C) N(140°C)].
• the inventive nucleating agent is more effective and versatile than the comparative compounds over a broad temperature range.
• a NEF is thus greater than about 0.06; more preferably, greater than about 0.08; still more preferably greater than about 0.10; and most preferably greater than about 0.12, since the greater the number, the greater the versatility of the nucleating agent.

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