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
  • C08K5/49—Phosphorus-containing compounds
  • C08K5/51—Phosphorus bound to oxygen
  • C08K5/52—Phosphorus bound to oxygen only
  • C08K5/524—Esters of phosphorous acids, e.g. of H3PO3
  • C08K5/526—Esters of phosphorous acids, e.g. of H3PO3 with hydroxyaryl compounds
• • 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
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/32—Compounds containing nitrogen bound to oxygen
• • 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
  • C08K5/49—Phosphorus-containing compounds
  • C08K5/51—Phosphorus bound to oxygen
  • C08K5/53—Phosphorus bound to oxygen bound to oxygen and to carbon only
  • C08K5/5317—Phosphonic compounds, e.g. R—P(:O)(OR')2
  • C08K5/5333—Esters of phosphonic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/12—Applications used for fibers
• • 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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2314/00—Polymer mixtures characterised by way of preparation
  • C08L2314/06—Metallocene or single site catalysts

Definitions

• This invention relates to polypropylene compositions useful in the manufacture of fibers and films.
• the invention relates to polypropylene compositions containing selected additives which provide for reduced devolatilization as evidenced by a reduction in the amount of smoke, oil and wax generated when such compositions are spun or extruded into fibers or films.
• N,N-dialkylhydroxylamines are recognized in the art as being useful process stabilizers for polyolefins including polypropylene. See for example USPs 4,590,231, 4,876,300 and WO 94/24344. USP 4,876,300 suggests that there are advantages in the use of long chain N,N-dialkylhydroxylamines as process stabilizers for polyolefins and teaches the use of such hydroxylamines in combination with other additives including organic phosphites in stabilizing polyolefins including low melt flow polypropylene.
• WO 94/24344 teaches a three component system for stabilizing polypropylene which includes a long chain N,N-dialkylhydroxylamine, an organic phosphite and a hindered amine.
• This publication suggests that the hindered a ine can replace conventionally used phenolic compounds to provide long term heat aging stability and that the three component system provides excellent resistance to gas fading. None of these patents suggest using the hydroxylamines alone or in combination with other additives such as organic phoshites to reduce the formation of smoke during melt extrusion of high melt flow polypropylene resins.
• the present invention relates to high melt flow polypropylene compositions which provide for reduced smoke formation when extruded into fibers or films.
• the inventive composition comprises a high melt flow polypropylene resin, a stabilizing amount of an N,N-dialkylhydroxylamine and a stabilizing amount of an organic phosphite or phosphonite and, optionally, other conventional additives such as antioxidants, acid acceptors, light stabilizers, ultraviolet light absorbers and the like.
• novel polypropylene compositions of the present invention comprise a high melt flow polypropylene resin, a stabilizing amount of an N,N-dialkylhydroxylamine and a stabilizing amount of an organic phosphite or phosphonite and, optionally, other conventional additives.
• High melt flow polypropylene resins useful in the composition of the present invention can be homopolymers of propylene, random copolymers of propylene with ethylene or higher alpha-olefins such as butene containing at least 70% by weight (w) preferably at least 80% w propylene, and polypropylene impact copolymers.
• the homopolymer phase of such impact copolymers is preferable a polypropylene homopolymer but may contain up to 5% w of a comonomer such as ethylene or a higher alpha-olefin.
• the rubber phase of the impact copolymer is a copolymer of ethylene and propylene with an ethylene content of between 30% w and 90% w, preferable 45% w to 75% w.
• the amount by weight of rubber phase present in the impact copolymer ranges between 5% w to 50% w and preferably from about 10% w and 35% w.
• the high melt flow polypropylene resins useful in the present invention have a melt flow of at least 20 dg/min (as determined by ASTM D-1238, Cond.
• Such high melt flow resins can be obtained directly in the polymerization reactor using certain "metallocene” catalysts such as those described, for example, in "Metallocene Catalyzed Polymers", edited by G. M. Benedikt and B. L.
• High melt flow polypropylene resins useful in the compositions of the present invention are advantageously prepared by contacting a low melt flow propylene polymer with an effective amount of an organic peroxide at elevated temperatures in an extruder.
• a peroxide particularly useful in the cracking of polypropylene resins is 2,5-dimethyl-2,5 bis(t-butylperoxy)hexane. Other peroxides known in the art could also be used.
• the amount of peroxide used and the cracking temperature will depend upon the melt flow of the starting polymer and the desired melt flow of the final product. Typically, the amount of peroxide used will range between 25 ppm and 5000 ppm. Temperatures in the extruder may range between 180° C and 320°C.
• N,N-dialkylhydroxylamines which are part of the compositions of the present invention are known in the art as secondary antioxidant additives useful for stabilizing polypropylene during melt processing.
• Many specific examples of N,N- dialkylhydroxylamine s useful in the present invention and methods of preparation are specifically disclosed in U.S. Pat. Nos. 4,590,231; 4,782,105; 4,876,300 and 5,013,510, the disclosures of which are incorporated herein by reference.
• Particularly useful in the compositions of this invention are the long chain N,N- dialkylhydroxylamines disclosed in U.S. Pat. No. 4,876,300 and having the formula
• Rl and R2 are independently alkyl groups having 12 to 18 carbon atoms.
• the most preferred alkyl groups for Rl and R2 are the alkyl mixture found in hydrogenated tallow amine.
• the amount of N,N- dialkylhydroxylamine incorporated into the compositions of the present invention to achieve the desired results will be in the range of 50 ppm to 5000 ppm based on the total composition and preferably in the range of 200 ppm to 1000 ppm.
• compositions of the present invention are known in the art as being useful as secondary antioxidants and stabilizers for polypropylene resins and are selected from the group consisting of:
• Tris(2,4-di-tert-butylphenyl) phosphite (IRGAFOS 168);
• Tris(2,4-di-tert-butylphenyl) phosphite is particularly useful and preferred as the organic phosphite which is part of the compositions of the present invention.
• the amount of organic phosphite or phosphonite incorporated into the compositions of the present invention should be in the range of 100 ppm to 5000 ppm, preferably in the range of 500 ppm to 2000 ppm .
• compositions of the invention also may contain additives which may be generally termed stabilizers, antioxidants, lubricants, acid acceptors, anti-static agents, nucleating additives and additives which stabilize against radiation, such as ultraviolet (UV) stabilizers and those that provide resistance to gamma irradiation.
• additives which may be generally termed stabilizers, antioxidants, lubricants, acid acceptors, anti-static agents, nucleating additives and additives which stabilize against radiation, such as ultraviolet (UV) stabilizers and those that provide resistance to gamma irradiation.
• UV ultraviolet
• Antioxidants which may be most useful in the compositions of the present invention include primary antioxidants of the phenolic-type. Their main function is to provide long-term thermal stability which is usually required in fabricated articles such as fibers and films.
• Preferred phenolic primary antioxidants include 1,3,5-tris- (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) l,3,5-triazine-2,4,6- (lH,3H,5H)-trione and tetrakis[methylene (3,5-di-tert-butyl-4- hydroxyhydrocinnamate)] methane.
• antioxidants include l,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxy-benzyl) benzene; octadecyl 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl) propionate ; tris[3,5-di- t-butyl-4-hydroxybenzyl) isocyanurate; 3,5-di-tert-butyl-4- hydroxyhydrocinnamic acid triester with l,3,5-tris(2-hydroxyethyl)-s- triazine-2,4,6(lH,3H,5H)-trione; bis-[3,3-bis(4'hydroxy-3'tert-butyl- phenyl)-butanoic acid]-glycolester; 2,2'-methylene-bis-(4-methyl-6- tertiary-butylphenol)-terephthalate; 2,2 bis
• Primary antioxidants such as those specified above may advantageously be combined with secondary antioxidants such as organic phosphites or phosphonites to provide the desired long term thermal stability for the compositions of this invention. To achieve the best results, it is desirable to keep the total amount of primary and secondary antioxidants present under about 1.5% by weight of the composition.
• Lubricants or mold release agents are typified by fatty acid amides, examples of which include ethylene bis stearamide, oleamide and erucamide.
• Acid acceptors may be categorized as salts of fatty acid, lactic acid salts and related derivatives, hydrotalcite-like compounds, and certain metal oxides. Examples of each type in order include calcium stearate, calcium lactate, DHT-4A, and zinc or magnesium oxide.
• Anti-static agents enhance static decay on molded parts.
• Key examples include glyceryl monostearate and glyceryl distearate, as well as mixtures thereof.
• Nucleating additives are typified by benzoic acid salts such as sodium, lithium or aluminum benzoate, minerals such as talc, and organophosphorous salts such as NA-11 and MARK 2180.
• Ultraviolet stabilization is provided by light absorbers such as TINUVIN 327 or by hindered amine types such as CYASORB 3346, TINUVIN 622, TINUVIN 770 DF and CHIMASSORB 944.
• Milliken's RS 200 additive is of benefit, as are mobilizing additives such as mineral oil (cited in U.S. Patents Nos. 4,110,185 and 4,274,932). The latter is used in combination with a non-phenolic secondary antioxidant and a hindered amine.
• additives discussed above may be used separately or blended with the primary antioxidants. This applies to all the above additive types and further includes fillers like barium sulfate, clays, calcium carbonate, silicates, pigments, such as titanium dioxide, zinc oxide, lead chromate, cadmium sulfides, cadmium selenide, zinc sulfide, basic carbonate of white lead; stabilizers such as tribasic lead sulfate, basic lead chlorosilicate, dibutyl tin oxide and other salts of lead, zinc, cadmium, tin, and the like; flame retardants such as antimony oxide; ultra-violet stabilizers, slip agents, anti-block agents, and other solid additives which enhance the properties and processability of the polymer to which they are added.
• fillers like barium sulfate, clays, calcium carbonate, silicates, pigments, such as titanium dioxide, zinc oxide, lead chromate, cadmium sulfides, cadmium seleni
• any additives including the N,N-dialkylhydroxylamine and organic phosphite or phosphonite compounds which are part of the compositions of the present invention may be incorporated into the high melt flow polypropylene resin by conventional techniques at any convenient stage prior to or during the extrusion of the compositions into shaped articles such as fibers or films.
• the additives may be mixed with the polypropylene resin in dry powder form or as a solution or suspension in an extruder prior to or during the process of cracking the resin or the process of pelletizing the resin.
• the effectiveness of the N,N- dialkylhydroxylamine and organic phosphite or phosphonite additive system in reducing smoke may be enhanced by employing the technique of "inerting" in the equipment used to extrude the novel polypropylene compositions of this invention and/or in the area surrounding such equipment.
• This technique involves maintaining an inert gas atmosphere such as nitrogen or carbon dioxide in the extrusion equipment including the extruder and die and/or in an enclosed space surrounding such equipment.
• the amount of smoke generated in the process of extruding several polypropylene compositions was measured and compared.
• the polypropylene resin component was the same in each composition tested and is identified as a polypropylene homopolymer having a melt flow (MF) of 38 dg/min which was obtained by peroxide cracking a nominal 3 MF polypropylene homopolymer produced in a gas phase reactor using a Zeigler-Natta catalyst.
• MF melt flow
• the amount of various additives present in each composition shown in Table I below is given in parts per million (ppm) by weight.
• the polypropylene resin composition to be tested was fed to a 5 inch slit film die with a 0.020 inch die gap using a Brabender 3/4 inch single screw extruder.
• the die was completely surrounded by an enclosure having an exhaust chimney at the top which was connected to an exhaust blower.
• the open bottom of the enclosure through which the polymer extrudate exits was attached to a fabric enclosure which surrounds the extrudate for a distance of 3 feet.
• the atmosphere surrounding the die is continuously withdrawn through the exhaust blower.
• the amount of smoke generated in the atmosphere surrounding the die during the extrusion of each formulation tested was measured using a model HAM-1010 particle detector manufactured by PPM, Inc. This particle detector, which works on a light scattering principal, was connected by sampling tubing to the exhaust chimney which is attached to the die enclosure. A flow meter and vacuum pump were connected to the particle detector.
• a Control average smoke density value was calculated and used to determine the Smoke Indicator number for the compositions tested which appears in Table I.
• the Control average smoke density value was determined by calculating the average of the average smoke densities of the first three compositions in Table I.
• the Control average smoke density value thus represents the average of the average smoke densities for the 9 test runs involved in Examples 1-3 in Table I.
• the compositions in Examples 1-3 are essentially the same and involve the presence of a known phenolic antioxidant process stabilizer, Irganox 3114 sold by Ciba.
• the Smoke Indicator number is calculated by dividing the average smoke density of the polypropylene composition of each Example by the Control average smoke density. The lower the Smoke Indicator number, the more resistant the composition is to the generation of smoke during melt extrusion.

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• Chemical & Material Sciences (AREA)
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• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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• 1999
  • 1999-08-25 AU AU57883/99A patent/AU5788399A/en not_active Abandoned
  • 1999-08-25 WO PCT/US1999/019605 patent/WO2000012605A1/en not_active Application Discontinuation
  • 1999-08-25 BR BR9913224-9A patent/BR9913224A/pt not_active IP Right Cessation
  • 1999-08-25 EP EP99945246A patent/EP1115783A1/de not_active Withdrawn
  • 1999-08-25 CA CA002341588A patent/CA2341588A1/en not_active Abandoned
  • 1999-08-25 JP JP2000567609A patent/JP2002523591A/ja active Pending

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