Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/02—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D01F6/04—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyolefins
  • D01F6/06—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyolefins from polypropylene
• • 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
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/34—Heterocyclic compounds having nitrogen in the ring
  • C08K5/3412—Heterocyclic compounds having nitrogen in the ring having one nitrogen atom in the ring
  • C08K5/3432—Six-membered rings
  • C08K5/3435—Piperidines
• • 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
  • C08K5/34—Heterocyclic compounds having nitrogen in the ring
  • C08K5/3467—Heterocyclic compounds having nitrogen in the ring having more than two nitrogen atoms in the ring
  • C08K5/3477—Six-membered rings
  • C08K5/3492—Triazines
  • C08K5/34926—Triazines also containing heterocyclic groups other than triazine groups
• • 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
  • C08K5/49—Phosphorus-containing compounds
  • C08K5/51—Phosphorus bound to oxygen
  • C08K5/52—Phosphorus bound to oxygen only
  • C08K5/527—Cyclic esters
• • 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
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/10—Other agents for modifying properties
• • 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
  • C08K2201/00—Specific properties of additives
  • C08K2201/019—Specific properties of additives the composition being defined by the absence of a certain additive

Definitions

• the instant invention pertains to stabilized polypropylene fiber, free or essentially free of any traditionally used phenolic antioxidant, and having enhanced light stability, enhanced long term heat stability and especially enhanced gas fade resistance.
• This fiber formu ⁇ lation is stabilized by an effective amount of a mixture of a selected hindered amine, a se ⁇ lected hydroxylamine and a selected phosphite.
• Polypropylene fiber is traditionally stabilized with a blend of selected phenolic antioxi ⁇ dant, selected phosphite and selected hindered amine light stabilizer.
• This formulation generally provides adequate processing, heat and light stabilization performance, but does not provide adequate gas fade resistance which is needed to maintain color properties during storage and end-use application.
• Gas fading is known in the industry as a discoloration re ⁇ sulting from the exposure of plastic articles to an atmosphere containing oxides of nitro ⁇ gen.
• the components of the instant stabilizer system for polypropylene fibers are generically well-known as stabilizers for a host of organic and polymeric substrates.
• the components of the instant stabilizer system for polypropylene fiber are a specific combination of selec ⁇ ted 2,2,6,6-tetramethylpiperidine hindered amines, phosphites or phosphorates and N,N- dialkylhydroxylamines, in the absence or essential absence of a phenolic antioxidant.
• This instant stabilizer formulation provides unexpectedly superior gas fade resistance, and heat and light stability performance properties to the polypropylene fibers which are notorious ⁇ ly difficult to stabilize effectively.
• the instant phenolic free antioxidant stabilizer system provides the best overall stabilization for polypropylene fiber.
• Discoloration of polypropy ⁇ lene fibers when exposed to an atmosphere containing oxides of nitrogen, i.e. gas fading conditions, encountered with stabilizer systems containing phenolic antioxidants, makes such systems unacceptable in this important property even though in other performance criteria the phenolic antioxidants perform adequately.
• the hindered amines are a very important class of light and thermal stabilizers based on compounds having a 2,2,6,6-tetramethylpiperidine moiety somewhere in the molecule. These compounds have achieved great commercial success and are well-known in the art.
• phosphonites or phosphites such as those described in US-A-4360 617 have also achieved great commercial success as stabilizers.
• N,N-Dialkylhydroxylamines also are known in the art as seen in US-A-4590 231, US-A-4782 105, US-A-4876 300 and US-A-5 013 510. These compounds are useful as process stabilizers for polyolefins when used alone or in combination with phenolic anti ⁇ oxidants and/or other coadditives, particularly as taught in US-A-4876 300.
• compositions of the prior art are distinguished from the compositions of the prior art in several important aspects listed below:
• Hindered phenolic antioxidants plus phosphites combinations have generally poor gas fade resistance
• Phosphites plus hindered amines lack adequate process stabilization.
• the instant combination of stabilizers provide all of the required requisites of gas fade resistance and process and thermal stability.
• the object of this invention is to provide a stabilizer system for polypropylene fiber, in the absence of any traditionally used phenolic antioxidant or in the presence of only very low levels of phenolic antioxidant, which would allow the polypropylene fibers to have en ⁇ hanced light and long term heat stability and especially enhanced gas fade resistance while maintaining process stabilization comparable to any system using phenolic antioxidants.
• Another object of the instant invention is to provide a method to improve gas fade re- sistance and to reduce color formation in polypropylene fibers by using the instant stabili ⁇ zer system free of phenolic antioxidant.
• the instant invention pertains to stabilized polypropylene fiber, free or essentially free of any phenolic antioxidant, and having enhanced light stability, enhanced long term heat stability and enhanced gas fade resistance, which fiber is stabilized by a mixture of
• a hydroxylamine selected from the group consisting of N,N-dioctadecylhydroxylamine
• N,N-dialkylhydroxylamine of the formula T 1 T 2 NOH where T 1 and T 2 are the all yl mixture found in hydrogenated tallow amine; and the N,N-diallcylhydroxylamine product made by the direct oxidation of N N-di(hydro- genated tallow)amine by the process of US-A-5 013 510 or US-A-4898 901;
• weight ratio of components (a):(b):(c) is from 1:1:1 to 100:2:1; preferably 10:1:1 to 10:2:1; and most preferably 6:1:1 to 6:2:1.
• the effective amount of the mixture of stabilizers is from 0.05 to 5 %, preferably 0.1 to 2 %, most preferably 0.15 to 1 %, by weight based on the weight of the fiber.
• Stabilized polypropylene fiber which are of particular interest are those where the compo ⁇ nent (a) is selected from the group consisting of
• Stabilized polypropylene fiber which are also of particular interest are those where the component (b) is selected from the group consisting of
• Stabilized polypropylene fiber which are particularly preferred are those where the com ⁇ ponent (c) is the N,N-dialkylhydroxylamine product made by the direct oxidation of N,N- di(hydrogenated tallow)amine by the process of US-A-5 013 510 or US-A-4898 901.
• the instant invention also pertains to a binary stabilizer system where the sta ⁇ bilized polypropylene fiber, free or essentially free of any phenolic antioxidant, and having enhanced light stability, enhanced long term heat stability and enhanced gas fade resistance, which fiber is stabilized by a mixture of
• Binary stabilized polypropylene fiber which are of particular interest are those where the component (I) is selected from the group consisting of
• Binary stabilized polypropylene fiber which are of particular interest are those where the component (II) is the N,N-dialkylhydroxylamine product made by the direct oxidation of N,N-di(hydrogenated tallow)amine by the process of US-A-5 013 510 or US-A-4 898 901.
• the effective amount of the mixture of stabilizers is from 0.05 to 5 %, preferably 0.1 to 2 %, most preferably 0.15 to 1 %, by weight based on the weight of the fiber.
• the instant invention involves a selected mixture of stabilizers which are free or essentially free of any phenolic antioxidants.
• Some manufacturers of polypropylene add tiny amounts, usually ⁇ 0.01 % by weight of phenolic antioxidant, to aid in the initial manufacture of the polypropylene resin.
• the amount of phenolic antioxidant remaining in the resin used to prepare polypropylene fiber is far less than the 0.05% by weight of phenolic antioxidant used in the working examples of US-A-4876300.
• free or essentially free of phenolic anti ⁇ oxidant as used in the context of the instant invention means 0 to 0.01 % by weight of phenolic antioxidant may be present in the instant compositions. No phenolic antioxidant is deliberately added to the instant compositions in order to achieve the stabilization efficacies described.
• Another most important aspect of the instant invention is to a method for improving gas fade resistance and reducing color formation in stabilized polypropylene fiber by incorpo ⁇ rating therein an effective stabilizing amount of the mixture of stabilizers described above without the loss of any other stabilization property.
• Still another aspect of the instant invention is to a method for enhancing the resistance to degradation of polypropylene fiber, due to exposure to UV radiation over that which can be achieved by the use of conventional stabilizers alone, by incorporating therein an effec ⁇ tive stabilizing amount of the mixture of stabilizers described above.
• Yet another aspect of the instant invention is to a method for enhancing the thermal stabi ⁇ lity of polypropylene fiber, over that which can be achieved by the use of conventional stabilizers alone, by incorporating therein an effective stabilizing amount of the mixture of stabilizers described above.
• the cited hindered amines and phosphites are generally commercially available or can be made by published methods.
• N,N-dialkylhydroxylamines are prepared by methods disclosed in US-A-4782 105; US-A-4 898 901 and particularly US-A-5 013 510 by the direct oxidation of N,N-di- (hydrogenated tallow)amine by hydrogen peroxide.
• the polypropylene fiber may also contain other additives such as fillers and reinforcing agents such as calcium carbonate, silicates, glass fibers, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black, graphite and other additives, for example, plasticizers, lubricants, emulsifiers, pigments, optical brighteners, flame- proofing agents and anti-static agents.
• additives such as fillers and reinforcing agents such as calcium carbonate, silicates, glass fibers, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black, graphite and other additives, for example, plasticizers, lubricants, emulsifiers, pigments, optical brighteners, flame- proofing agents and anti-static agents.
• Conventional stabilization systems such as phenolic antioxidant with phosphite and hindered amine stabilizer, or phosphite with hindered amine stabilizer, can provide excel ⁇ lent stabilization to polypropylene fibers in selected performance areas, but it is only through the use of the instant ternary combination of a selected hindered amine, selected hydroxylamine and selected phosphite that all important performance properties for sta ⁇ bilized polypropylene fibers can be optimized.
• Polypropylene is used extensively for the manufacture of fiber for residential, commercial and automotive carpeting. White and light-colored fiber can suffer from discoloration due to gas fade discoloration.
• Polypropylene resin as it is originally manufactured may contain very low levels of phenolic antioxidant for stability till said resin is later fabricated into fiber. In each case some additional stabilizer package must be added to the propylene resin before fabrication into fiber is possible.
• Hindered phenolic antioxidants are well-known as a potential source of such discoloration by the formation of quinone type chromophores as oxidation products or as the result of environmental exposure to the oxides of nitrogen (known as "gas fade" discoloration).
• Phenolic antioxidants protect the polymer during high temperature melt processing, extrusion and spinning operations. Phenolic antioxi ⁇ dants further protect the polymer pellets and resultant fiber during storage and final end- use applications.
• the phenolic antioxidant could be replaced in the instant stabilizer system which is a ternary combination of a selected hindered amine, a selected hydroxylamine and a selected phosphite or a binary combination of a selected hindered amine and a selected hydroxylamine.
• Said system provides stability in excess of that ob ⁇ tained with conventional stabilizer systems having a phenolic antioxidant component without the discoloration associated with the phenolic antioxidant when the stabilized polypropylene fiber is exposed to gas fading conditions, i.e. in an atmosphere containing the oxides of nitrogen.
• AO A l,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate
• HALS 1 the polycondensation product of 4,4'-hexamethylene-bis(amino-2,2,6,6- tetramethylpiperidine) and 2,4-dichloro-6-tert-octylamino-s-triazine;
• HALS 2 the polycondensation product of l-(2-hydroxyethyl)-2,2,6,6-tetramethyl- 4-hydroxypiperidine and succinic acid;
• HALS 3 N,N',N ,, ,N'"-tetralds[4,6-bis(butyl-(2,2,6,6-tetramethylpiperidin-4-yl)- amino)-s-triazin-2-yl]-l,10-diamino-4,7-diazadecane;
• HALS 4 the polycondensation product of 4,4'-hexamethylene-bis(amino-2,2,6,6- tetramethylpiperidine) and 2,4-dichloro-6-morpholino-s-triazine;
• HALS 5 polyfmethyl 3-(2,2,6,6-tetramethylpiperidin-4-yloxy)propyl]siloxane
• HALS 6 bis(2,2,6,6-tetramethylpiperidin-4-yl) cyclohexylenedioxydimethyl- malonate
• HALS 7 l,3,5-tris ⁇ N-cyclohexyl-N-[2-(2,2,6,6-tetramethyl ⁇ iperazin-3-on-4-yl)- ethyl]amino-s-triazine;
• Phos I tris(2,4-di-tert-butylphenyl) phosphite
• Phos m 2,2 , ,2"-nitrilo[triethyl-tris-(3,3',5,5'-tetra-tert-butyl-l,l'-biphenyl-2,2'- diyl) phosphite];
• Phos IV ethyl bis(2,4-di-tert-butyl-6-methylphenyl) phosphite
• HA A the N,N-dialkylhydroxylamine product made by the direct oxidation of
• All additives are designated in % by weight based on the polypropylene. All formulations also contain 0.05% by weight of calcium stearate.
• Example 1 Process Stabilization of Polypropylene Fiber.
• Fiber grade polypropylene containing 0.05 % by weight of calcium stearate, is dry blen ⁇ ded with the test additives and then melt compounded at 246°C into pellets.
• the pelletized fully formulated resin is then spun at 274°C into fiber using a Hills laboratory model fiber extruder.
• the spun tow of 41 filaments is stretched at a ratio of 1: 3.2 to give a final denier of 615/41.
• melt flow rates of the formulated pellets before spinning and of the spun fiber tow after spinning are determined by ASTM 1238-86. The closer are the melt flow rates before and after spinning, the more effective is the process stabilization efficacy of the stabilizer system.
• processing stability data are given in Tables 1, 2, 3 and 4 below.
• HALS 2 0.30 % Phos I 0.05 % 13.8 18.3 HAA 0.05 %
• HALS 2 0.05 % Phos I 0.05 % 14.4 18.7 HAA 0.05 %
• HALS 3 0.30 % Phos I 0.05 % 14.2 17.5 HAA 0.05 %
• Example 1 Melt flow differences resulting from insufficient processing stability can be even more evident when the polypropylene is spun under more severe processing conditions.
• Example 1 the polypropylene is spun at 274°C. However, it is not unusual for polypropylene to be spun at much higher temperature at 302°C.
• the melt flow values of polypropylene spun at such tempe ⁇ ratures are shown in the Tables 5, 6, 7 or 8 below.
• HALS 2 0.05 % Phos I 0.05 % 13.7 17.4 HAA 0.05 %
• HALS 2 0.05 % Phos I 0.10% 13.6 16.1 HAA 0.05 %
• HALS 3 0.05 % Phos I 0.05 % 12.4 16.9 HAA 0.05 %
• Example 3 Light Stabilization of Polypropylene Fiber.
• the fibers are also exposed to UV light and to long term thermal aging under standard conditions.
• Socks knitted from the stabilized polypropylene fibers are exposed in an Atlas Xenon- Arc-WeatherOmeter using the SAE J1885 Interior Automotive conditions at 89°C, 0.55 kW/cm 2 at 340 nm with no spray cycle. Failure in this test is determined by the observa- tion of the physical failure of the sock when it is "scratched" with a blunt glass rod. The longer it takes for this catastrophic failure to occur, the more effective is the stabilizer system. The days to failure are given in Tables 9, 10, 11 and 12 below for each of the sta ⁇ bilization systems.
• HALS 3 0.30 % Phos I 0.05 % 37 HA A 0.05 %
• Example 4 Long Term Heat Stability of Polypropylene Fiber.
• HALS 2 0.30 % Phos I 0.05 % 72 HA A 0.05 %
• HALS 3 0.30 % Phos I 0.05 % 75 HA A 0.05 %
• Examples 5-6 show that, in regards to gas fade resistance, the instant stabilization mixture is far superior as measured by Delta E values where low numbers indicate less color. The numerical differences shown are significant, and the samples can be easily differentiated visually.
• Example 5 Gas Fade Resistance or Color Stability of Polypropylene Fiber.
• HALS 2 0.30 % Phos I 0.09 % 1.6 1.5 HAA 0.01 %
• HALS 2 0.30 % Phos I 0.05 % 1.5 1.9 HAA 0.05 %
• HALS 2 0.30 % AOA 0.05 % 3.9 5.3 Phos I 0.09 % HAA 0.01 %
• HALS 2 0.30 % AOA 0.05 % Phos I 0.05 % 1.9 3.7 HAA 0.05 %
• HALS 2 0.05 % Phos I 0.09 % 1.6 1.5 HAA 0.01 %
• HALS 2 0.05 % Phos I 0.05 % 1.0 1.3 HAA 0.05 %
• HALS 2 0.05 % AOA . 0.05 % 3.8 4.9 Phos I 0.09 % HAA 0.01 %
• HALS 2 0.05 % AOA 0.05 % Phos I 0.05 % 2.0 3.9 HAA 0.05 % Table 20:
• HALS 3 0.30 % Phos I 0.05 % 1.7 1.9 HAA 0.05 %
• HALS 3 0.30 % AOA 0.05 % 4.8 6.7 Phos I 0.09 % HAA 0.01 %
• HALS 3 0.30 % AOA 0.05 % Phos I 0.05 % 3.1 5.3 HAA 0.05 %
• HALS 3 0.05 % Phos I 0.05 % 1.2 1.3 HAA 0.05 %
• HALS 3 0.05 % AOA 0.05 % 4.0 5.3 Phos I 0.09 % HAA 0.01 %
• HALS 2 0.05 % Phos II 0.05 % 1.5 1.8 HA A 0.05 %
• HALS 2 0.05 % AO A 0.05 % 1.9 3.1 Phos H 0.05 % HA A 0.05 %
• HALS 4 0.30 % Phos I 0.05 % 1.2 HAA 0.05 %
• HALS 5 0.30 % Phos I 0.05 % 1.0 HAA 0.05 %
• HALS 6 0.30 % Phos I 0.05 % 1.0 HAA 0.05 %
• melt flow differences resulting from insufficient processing stability are quite evident when toe polypropylene is spun under severe processing conditions. This is particularly evident when polypropylene is spun at 302°C. The lower the melt flow rates are the more effective is the process stabilization efficacy of the stabilizer system (see also example 1). The melt flow values of polypropylene spun at that temperature are shown in the Tables 29, 30 and 31 below.
• HALS 1 0.05 % Phos I 0.05 % 18 HA A 0.05 %
• HALS 2 0.05 % Phos I 0.10 % 15 AO A 0.05 %
• HALS 2 0.05 % Phos I 0.05 % 19 HA A 0.05 %
• HALS 2 0.05 % 18 HA A 0.05 %
• HALS 3 0.05 % Phos I 0.05 % 17 HA A 0.05 %
• HALS 3 0.05 % 17 HA A 0.05 %

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