DK175151B1 - Stabilized polypropylene fibers, as well as methods for increasing gas bleach resistance and reducing color formation, increasing resistance to degradation due to exposure to UV radiation and increasing thermal stability .... - Google Patents

Description

in DK 175151 B1

The present invention relates to stabilized polypropylene fibers which are free of or substantially free of any traditionally used phenolic antioxidant and which have enhanced light stability, increased long-term heat stability and, in particular, increased gas-bleaching resistance. This fiber composition is stabilized with an effective amount of a mixture of a selected hindered amine, a selected hydroxylamine and a selected phosphite. The invention also relates to a method of increasing gas bleach resistance 10 and reducing color formation, increasing degradation resistance due to exposure to UV radiation and increasing the thermal stability of polypropylene fibers.

Polypropylene fibers are traditionally stabilized with a mixture of selected phenolic antioxidant, selected phosphite, and selected hindered amine light stabilizer. This composition generally provides appropriate treatment or manufacture, heat and light stabilization, but does not provide sufficient gas-bleach resistance, which is required to maintain color properties during storage and in end use. There has been a long-standing need for a stabilizer system on the market that can prevent this gas bleaching and color formation associated with the use of phenolic antioxidants. Gas bleaching is known in the industry as a discoloration that results from exposing plastic articles to an atmosphere containing oxides of nitrogen.

The components of the polypropylene fiber stabilizer system of this invention are generically known as stabilizers 30 for a host of organic and polymeric substrates. The components of the present polypropylene fiber stabilizer system are a specific combination of selected 2,2,6,6-tetramethylpiperidine-hindered amines, phosphites or phosphonites and Ν, Ν-dialkylhydroxylamines, in the absence or substantial absence of a phenolic antioxidant. The present stabilizer composition unexpectedly provides superior gas-bleaching resistance and heat and light stability properties for the polypropylene fibers, which are notoriously difficult to stabilize effectively. The present phenol-free antioxidant stabilizer system provides the best overall stabilization for polypropylene fibers. Discoloration of polypropylene fibers when exposed to an atmosphere containing oxides of nitrogen, i.e. gas-bleaching conditions, which occur in connection with stabilizer systems containing phenolic antioxidants, cause such systems to be unacceptable for this important property, although the phenolic antioxidants for other property criteria have appropriate characteristics.

The hindered amines are a very significant class 15 of light and heat 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.

Likewise, phosphonites or phosphites, e.g.

20 described in US-A-4,360,617 also achieved great commercial success as stabilizers.

Ν, Ν-Dialkylhydroxylamines are also known in the art as disclosed in US-A-4,590,231 corresponding to EP-A-0138,767, US-A-4,782,105, US-A-4,876,300 corresponding to to EP-A-25 0323,409 and US-A-5,013,510. These compounds can be used as process stabilizers for polyolefins when used alone, or in combination with phenolic antioxidants and / or other co-additives, particularly as disclosed in US-A-4,876,300. Although US-A-4,876,300 generically states that 30 Ν, dial-dialkyl hydroxylamines can be used in combination with phenolic antioxidants, hindered amines, phosphites, UV absorbers and other additives, there is no specific indication that polypropylene fibers with good result can be stabilized by specific combinations of 35 selected hindered amines, phosphites or phosphonites and Ν, Ν-dialkyl hydroxylamines. Thus, the present invention is essentially a selection from the broad generic scope of US-A-4,876,300.

However, the present composition differs from the prior art compositions in several significant respects, set forth below: 1. Obstructed phenolic antioxidants plus phosphite combinations generally have poor gas bleaching resistance.

10 2. Phosphites alone lack appropriate process and thermal stabilization efficiency and 3. Phosphites plus hindered amines lack appropriate process stabilization.

The present combination of stabilizers provides all the required properties with respect to gas bleach resistance and process and thermal stability.

The object of the present invention is to provide a stabilizer system for polypropylene fibers, in the absence of any traditionally used phenolic antioxidant or in the presence of only very low amounts of phenolic antioxidant which will allow the polypropylene fibers to have increased light stability and long term heat stability and especially increased resistance to gas bleaching, while maintaining a process stabilization comparable to any system in which phenolic antioxidants are used.

Another object of the present invention is to provide a method for improving gas bleach resistance and for reducing color formation in polypropylene fibers using the present phenolic antioxidant stabilizer system.

The present invention relates to stabilized poly-35 propylene fibers which are free of or substantially free of any phenolic antioxidant and which have increased light stability, increased long-term heat stability and increased resistance to gas bleaching, which fibers are stabilized with a mixture of a) a hindered amine selected from the group consisting of the polycondensation product of 4,4'-hexamethylene bis- (amino-2,2,6, β-tetramethylpiperidine) and 2,4-dichloro-6- tert.octylamino-s-triazine, the polycondensation product of 1- (2-hydroxyethyl) - 2,2,6,6-tetramethyl-4-hydroxy-piperidine and succinic acid, 10 N, N ', N ", N"' - tetrakis - [4,6-Bis- (butyl- (2,2,6,6-tetramethylpiperidin-4-yl) -amino) -s-triazin-2-yl] -1,10-di-amino-4 , 7-diazadecane, the polycondensation product of 4,4'-hexamethylene bis- (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-15-6-morpholino-s-triazine, poly- [methyl - 3- (2,2,6,6-tetramethylpiperidin-4-yl-oxy) -propyl] -siloxane, bis- (2,2,6,6-tetramethylpiperidine) n-4-yl) -cyclohexylene-dioxydimethylmalonate, 1,3,5-tris- (N-cyclohexyl-N- [2- (2,2,6,6-tetramethylpiperazin-3-one-4-yl) ) -ethyl] -amino-s-triazine, the polycondensation product of 4,4'-hexamethylene-bis- (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-cyclohexylamino-s-triazine and poly- (N- [4,6-bis- (butyl- (2,2,6,6-tetramethyl-piperidin-4-yl) -amino) -s-triazin-2-yl) -1 4,7-Triazanonan} -ω-Ν "- [4,6-bis- (butyl- (2,2,6,6-tetramethylpiperidin-4-yl) -amino) -s-triazin-2-yl] -amine, b) a phosphite or phosphonite selected from the group consisting of tris- (2,4-di-tert.-butylphenyl) -phosphite, 3,9-di- (2,4-di-tert.-butylphenyl) 2,4,8,10-tetraoxa-3,9-diphospha [5.5] undecane, 2,2 ', 2 "- nitrilo tris - [ethyl - (3,3', 5,5 '' tetra tert) -butyl-1,1'-biphenyl-2,2'-diyl) phosphite], ethyl bis (2,4-di-tert.butyl-6-methylphenyl) phosphite) (2,4-di-tert. but c) N, N - dialkylhydroxylamine product produced by the direct oxidation of N, N-di- (hydrogenated tallow) amine by oxidation of a butylphenyl) -4,4'-bis (diphenylene) phosphonite solution of N, N-di- (hydrogenated tallow) amine in a lower alkanol solvent with a molar excess of 10-70% aqueous hydrogen peroxide solution at a temperature of 40-65 ° C, where the weight ratio of constituents (a) · . (b): (c) ranges from 1: 1: 1 to 100: 2: 1, preferably from 10: 1: 1 to 10: 2: 1 and most preferably from 6: 1: 1 to 6: 2: 1.

The effective amount of the mixture of stabilizers 15 is e.g. from 0.05 to 5%, preferably from 0.1 to 2%, most preferably from 0.15 to 1%, by weight based on the weight of the fiber.

Stabilized polypropylene fibers of particular interest are those in which component (a) is selected from the group 20 consisting of the polycondensation product of 4,4'-hexamethylene-bis-amino-2,2,6,6-tetramethylpiperidine) and 2 , 4-dichloro-6-tert. octylamino-s-triazine, the polycondensation product of 1- (2-hydroxyethyl) -2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, N, N 1, N ", N" -tetrakis [4,6 -bis- (butyl- (2,2,6,6-tetra-methylpiperidin-4-yl) -amino) - s-triazin-2-yl] -1,10-diamino-4,7-diazadecane, the polycondensation product of 4,4'-hexamethylene bis-30 (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-morpholino-s-triazine, poly [methyl-3- (2.2, 6,6-tetramethylpiperidin-4-yloxy) -propyl] -siloxane, bis- (2,2,6,6-tetramethylpiperidin-4-yl) -cyclohexylene-dioxydimethylmalonate and 1,3,5-tris- {N- cyclohexyl-N- [2- (2,2,6,6-tetramethyl-1-piperazin-3-one-4-yl) -ethyl] -amino-s-triazine.

Stabilized polypropylene fibers which are also of particular interest are those in which component (b) is selected from the group consisting of 5-tris- (2,4-di-tert.butylphenyl) phosphite, 3.9-di- (2.4 di-tert.butylphenyl) -2,4,8,10-tetraoxa-3.9-diphospha [5.5] undecane, 2,2 ^ 211 -nitrilo-tris- [ethyl (3,3 ', 5,5' -tetra) tert-butyl-1,11-biphenyl-2,21-diyl) phosphite] and ethyl bis (2,4-di-tert-butyl-6-methylphenyl) phosphite.

Particularly preferred stabilized polypropylene fibers are those in which component (c) is the N, N-dialkyl-hydroxylamine product produced 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.

In addition, the present invention also relates to stabilized polypropylene fibers which are free or substantially free of any phenolic antioxidant and have increased light stability, increased long-term heat stability and increased gas-bleaching resistance, which fibers are stabilized with a mixture of I ) an hindered amine selected from the group consisting of the polycondensation product of 4,4'-hexamethylene bis- (amino-2,2,6,6-tetramethyl-piperidine and 2,4-dichloro-6-tert-octylamino-5 triazine, the polycondensation product of 1- (2-hydroxyethyl) - 2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, Ν, Ν ', N ", Ν'" - tetrakis- [4,6-bis- butyl- (2,2,6,6-tetra-methylpiperidin-4-yl) amino) -s-triazin-2-yl] -1,10-30 diamino-4,7-diazadecane, the polycondensation product of 4.4 -hexamethylene bis- (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-morpholino-s-triazine, poly- [methyl-3- (2,2,6,6- tetramethylpiperidin-4-yloxy) -propyl] -siloxane, bis - (2,2,6,6-tetramethylpiperidin-4-yl) - cyclohexylene ...... - 7 DK 175151 B1 dioxydimethylmalonate, 1,3,5-tris- {N-cyclohexyl-N- [2- (2,2,6,6-tetramethyl-piperazin-3-one 4-yl) -ethyl] -amino-5-triazine and the polycondensation product of 4,4'-hexamethylene-bis-5 (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-cyclohexylamino -s-triazine and II) N, N-dialkylhydroxylamine product produced by the direct oxidation of N, N-di- (hydrogenated tallow) -amine by oxidation of a solution of N, N-di-10 (hydrogenated tallow) - amine in a lower alkanol solvent having a molar excess of 10-70% hydrogen peroxide at a temperature of 40-65 ° C where the weight ratio of constituents (I): (II) ranges from 100: 1 to 1: 2; preferably from 10: 1 to 1: 1 and most preferably from 5: 1 to 3: 1.

Binary stabilized polypropylene fibers of particular interest are those wherein component (I) is selected from the group consisting of the polycondensation product of 4,4'-hexamethylene bis-20 (amino-2,2,6,6-tetramethylpiperidine) and 2 , 4-dichloro-6-tert-octylamino-s-triazine, the polycondensation product of 1- (2-hydroxyethyl) - 2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid and N, Ν ', N ", N "-Tetrakis [4,6-bis (butyl- (2,2,6,6-tetramethylpiperidin-4-yl) -amino) -s-triazin-2-yl] -1,10-dia- mino-4,7-diazadecane.

The effective amount of the mixture of stabilizers is from 0.05 to 5%, preferably from 0.1 to 2%, most preferably from 0.15 to 1%, by weight based on the weight of the fibers.

The present invention comprises a selected blend of stabilizers which are free of or substantially free of any phenolic antioxidant. Some polypropylene manufacturers add very small amounts, usually <0.01 to 35% by weight of phenolic antioxidant, to aid in the initial preparation of the polypropylene resin. The amount of phenolic residue remaining in the resin used to make polypropylene fibers is far less than the 0.05 wt.% Phenolic antioxidant used according to the exemplary embodiments of US-A-4,876,300. The term "free of 5 or substantially free of phenolic antioxidant" as used in the present invention means that from 0 to 0.01% by weight of phenolic antioxidant may be present in the present compositions. No phenolic antioxidant is intentionally added to the 10 compositions of this invention to achieve the stabilizing effects described.

Another, most significant aspect of the present invention is a method as claimed in claims 6 and 13 for improving gas-bleaching resistance and reducing color formation in stabilized polypropylene fibers by incorporating therein an effective stabilizing amount of the above-described mixing of stabilizers without loss of any other stabilizing property.

A further aspect of the present invention 20 is a method as claimed in claims 7 and 14 for increasing the resistance to degradation of polypropylene fibers due to exposure to UV irradiation, relative to the resistance obtainable using conventional stabilizers. alone, by incorporating therein an effective stabilizing amount of the above-described mixture of stabilizers.

Yet another aspect of the present invention is a method as claimed in claim 8 for increasing the thermal stability of polypropylene fibers relative to the stability that can be used using conventional stabilizers alone, by incorporating therein an effective stabilizing amount of the mixture of stabilizers described above.

Said hindered amines and phosphites are generally commercially available or can be prepared by published methods.

The N, N-dialkyl hydroxylamines are prepared by methods described in US-A-4,782,105, US-A-4,898,901, and in particular US-A-5,013,510, by the direct oxidation of N, II-di - (hydrogenated tallow) amine with hydrogen peroxide.

The polypropylene fibers may also contain other additives such as fillers and reinforcing agents, e.g. calcium carbonate, silicates, glass fibers, asbestos, talc, kaolin, mica, barium sulphate, metal oxides and hydroxides, carbon black, graphite and other additives, e.g. emollients, lubricants, emulsifiers, pigments, optical cleaners, fire retardants and antistatic agents. .

Conventional stabilization systems, e.g. Phenolic antioxidant with phosphite and hindered amine stabilizer, or phosphite with hindered amine stabilizer, can provide excellent stabilization to polypropylene fibers in selected applications, but it is only through the use of the present ternary combination of a selected hindered amine, a selected hydroxylamine and a selected phosphite, that all significant application properties of stabilized polypropylene fibers can be optimized.

Polypropylene is widely used in the manufacture of fiber for residential, commercial and automotive carpets. White and light colored fibers may suffer from discoloration due to gas bleaching discoloration.

Polypropylene resin, as originally manufactured, may contain very low amounts of phenolic antioxidant for stability purposes until the resin is later used in the manufacture of fibers. In each case, some additional stabilizer composition must be added to the propylene resin before making fibers possible. Obstructed phenolic antioxidants are well known as a potential source of such discoloration in the formation of quinone-type chromophores as oxidation products or as the result of exposure to the oxides of nitrogen in the environment (known as "gas-bleaching" discoloration).

It is therefore desirable to remove the phenolic antioxidant component from the polypropylene fibers. Unfortunately, once this has been done, other properties related to polymer stability have been adversely affected. Phenolic antioxidants protect the polymer during high temperature melt processing, extrusion and spinning. Phenolic antioxidants further protect polymer pellets and resultant fibers during storage and in end applications.

Surprisingly, it has been found that the phenolic antioxidant can be substituted in the present stabilizer system, which is a ternary combination of selected hindered amine, a selected hydroxylamine and a selected phosphite, or a binary combination of a selected hindered amine and a selected hydroxylamine. . This system provides stability beyond that obtained with conventional stabilizer systems having a phenolic antioxidant component, without the discoloration associated with the phenolic antioxidant when the stabilized polypropylene fiber is subjected to gas bleaching conditions, i.e. in an atmosphere containing the oxides 20 of nitrogen.

The following examples are given for illustrative purposes only.

Test compounds 25 AO A = 1,3,5-tris- (3,5-di-tert.butyl-4-hydroxybenzyl) isocyanurate, HALS 1 = the polycondensation product of 4,41-hexamethylene bis- (amino-2.2 , 6,6-tetramethylpiperidine) and 2,4-dichloro-6-tert-octylamino-s-triazine, HALS 2 = the polycondensation product of 1- (2-hydroxyethyl) - 2,2,6,6-tetramethyl-4 - hydroxypiperidine and succinic acid, HALS 3 = N, N ', N ", N"' - tetrakis- [4,6-bis- (butyl- (2,2,6,6-tetramethylpiperidin-4-yl) -amino) ) -s-triazin-2-yl] - 1,10-diamino-4,7-diazadecane, HALS 4 = the polycondensation product of 4,41-hexamethylene bis- (amino-2,2,6,6-tetramethylpiperidine) and 2,4- - 11-dichloro-6-morpholino-5-triazine, HALS 5 = poly [methyl-3- (2,2,6,6-tetramethylpiperidin-4-yloxy) propyl] siloxane , HALS 6 = bis- (2,2,6,6-tetramethylpiperidin-4-yl) -cyclohexylenedioxydimethylmalonate, HALS 7 = 1,3,5-tris- (N-cyclohexyl-N- [2- (2) , 2,6,6-tetramethylpiperazin-3-one-4-yl) ethyl] -amino-s-triazine,

Phos I = tris (2,4-di-tert.butylphenyl) phosphite,

Phos II = 3,9-di- (2,4-di-tert.butylphenyl) -2,4,8,10-tetra-oxa-3,9-diphospha [5.5] undecane,

Phos III = 2,2 ', 2 "-nitrolo- [triethyl-tris- (3,3', 5,5'-tetra-tert-butyl-1,1'-biphenyl-2,2'-diyl) - phosphite],

Phos IV = ethyl bis (2,4-di-tert-butyl-6-methylphenyl) phosphite, and HA HA = N, N-dialkylhydroxylamine product prepared 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.

All additives are given in% by weight of the polypropylene. All compositions also contain 0.05% by weight of calcium stearate.

Example 1

Process stabilization of polypropylene fibers.

Fiber grade polypropylene containing 0.05% by weight of calcium stearate is dry mixed with the test additives and then melted at 246 ° C to pellets. The pelletized, fully formulated resin is then spun at 274 ° C into fibers using a Hills laboratory fiber extruder. The spun tow of 41 filaments is stretched at a ratio of 1: 3.2 to a final denier value of 615/41.

The melt flow rates of the formulated pellets before spinning and for the spun fiber tow after spinning are determined in accordance with ASTM 1238-86. The closer the 35 melt flow rates are before and after spinning, the more efficient is the process stabilization efficiency of the stabilizer system. The process stability data is given in the following Tables I, II, III and IV.

Table I:

Melt Flow Rate

Stabilizer Amount - -

Pellets Fiber HALS 1 0.30%

Phosl 0.09% 15.4 20.7 HA A 0.01% NECK 1 0.30%

Phos1 0.05% 14.9 19.6 HA A 0.05% NECK 1 0.05%

Phos I 0.09% 13.6 17.7 HA A 0.01% NECK 1 0.05%

Phos I 0.05% 13.6 18.8 HA A__0.05% ___ AO A 0.05% HALSI 0.05% 143

Phos1 0.05% V 19> 3 HA A 0.05%

Table II: __,

Melt Flow Rate

Stabilizer Amount —---

Pellets Fiber HALS 2 0.30%

Phos I 0.09% 13.7 18.6 HA A 0.01% NECK 2 0.30%

Phos1 0.05% 13.8 18.3 HA A 0.05% NECK 2 0.05%

Phosl 0.09% 13.4 17.8 HA A 0.01% NECK 2 0.05%

Phos1 0.05% 14.4 18.7 HAA__0.05% ___ AO A 0.05% NECK 2 0.05% 19 0 i o -i

Phosl 0 * 05% HA HA 0.05% 13 B1

Table III: __

Melt Flow Rate

Stabilizer Amount -

Pellets Fiber NECK 3 0.30%

Phosl 0.09% 13.3 19.3 HA A 0.01% NECK 3 0.30%

Phos1 0.05% 14.2 17.5 HA A 0.05% NECK 3 0.05%

Phosl 0.09% 14.3 18.6 HAA 0.01% NECK 3 0.05%

Phos1 0.05% 13.7 18.4 HA A__0.05% ___ AO A 0.05% NECK 3 0.05%, λο 17 <-

Phos1 0.05% 12.8 17.5 HA A 0.05%

Table IV: __

Smelteflydehastighéd

Stabilizer Amount —-

Pellets Fiber HALS 2 0.05%

Phos 5 0.05% 12.7 16.9 HA A 0.05% AO A 0.05% NECK 2 0.05% in λ g in g 2

Phos 5 0.05% ^ 'HA A 0.05% 14 DK 175151 B1

Examination of the data set forth above shows that the present compositions containing selected hindered amines, phosphites and hydroxylamines provide excellent process stabilization for polypropylene, a stabilization fully comparable to stabilizer systems containing phenolic antioxidants.

Example 2: Process Stabilization of Polypropylene Fibers.

Melting noise that results from insufficient process stability may be even more evident when the polypropylene is spun under more severe process conditions. In Example 1, the polypropylene is spun at 274 ° C. However, it is not unusual for polypropylene to be spun at a much higher temperature of 302 ° C. The melt flow rates of polypropylene spun at such temperatures are shown in the following Tables V, VI, VII or VIII.

Table V; ____

Melt Flow Rate

Stabilizer Amount of Fiber Spun Fiber Spun

at 274 ° C at 302 ° C

Phos I 0.15% __ 14 / 6__26.9

Phos I 0.10% after 155 AQA__0.05% ____ '

Phos I 0.05% 177 161 AO A 0.05% ____ '

Phos I 0.10% 13 5 16.2 HAA__0.05% ____ NECK 2 0.05% 14 7 · o 1 o

Phos I__0.10% __ 3 __ * NECK 2 0.05%

Phos I 0.10% 14.3 16.3 AQA__0.05% ____ NECK 2 0.05%

Phos I 0.05% 13.7 17.4 HA A 0.05% ___ NECK 2 0.05%

Phos I 0.10% 13.6 16.1 HA A 0.05%

Table VI: 15 DK 175151 B1

Melt Flow Rate

Stabilizer Amount of Fiber Spun Fiber Spun

at 274 ° C at 302 ° C

Phos Π 0.15% 13.7 20.1

PhOSII 0.10% AO A 0 ,0 0.05% ^

Phos Π 0.10% ^^ HALS 2 0.05%

PhosH 0.10% 12.2 15.5 AO A 0.05% NECK 2 0.05%

PhosH 0.05% 12.4 15.5 HA A 0.05% NECK 2 0.05%

Phos Π 0.10% 12.7 15.6 HA A 0.05%

Table, VII: _ • Melt flow rate

Stabilizer Amount of Fiber Spun Fiber Spun

at 274 ° C at 302 ° C

Phos I 0.15% 14.6 26.9

Phos I 0.10% ι <ια icc AO A__0.05% ____ 1 NECK 3 0.05% 14c, u ·

Phos I 0.10%

Phos I 0.10% 13.5 15.1 AO A 0.05% NECK 3 0.05%

Phos I 0.05% 12.4 16.9 HAA 0.05% NECK 3 0.05%

Phos I 0.10% 12.9 16.7 HA A 0.05% DK 175151 B1

16 I

Table VIII: __ I

- Melt flow rate I

5 V "; I

Stabilizer Amount of Fiber Spun Fiber Spun I

I at 274 ° C at 302 ° C

Phos Π 0.15% __ 13 £ __20.1 I

I 10 Phos Π 0.10% 13 o 16.5 I

AO A__0.05% ____ 1_

I NECK 3 0.05% 14 1 22.8 I

Phosn__0,10% __ 21__

NECK 3 0.05% I

In Phosn 0.05% 13.1 14.9 I

I 15 HAA 0.05% ___ I

NECK 3 0.05% I

In Phosn 0.10% 12.5 15.4 I

I HA A 0.05% I 1

The data in Tables V, VI, VII and vm clearly show, I

In a conventional stabilizer system, an I

In combination of phenolic antioxidant and phosphite a good 'I

In process or processing stability. The removal of the phe- I

In nolic antioxidant in the presence or absence of an I

In inhibited amine results in a significant loss of process stability

In lysis. The replacement with a hydroxylamine instead of the I

However, in phenolic antioxidant, a process I provides

In stabilization that is fully comparable to the one you

You are provided with the system of phenolic antioxidant and I

In phosphite. IN

As shown in Example 5, the presence I

However, I of phenolic antioxidant in stabilizer systems I

In a devastating effect on gas deflection resistance

In it. IN

I 35 I

17 DK 175151 B1

Example 3: Light stabilization of polypropylene fibers.

The fibers are also exposed to UV light and to long-term thermal aging under standard conditions.

Socks knitted from the stabilized polypropylene-5 fibers are tested in an Atlas Xenon-Arc-WeatherOmeter using SAE J1885 Interior Automotive conditions at 89 ° C, 0.55 kW / cm 2 at 340 nm without any spray cycle. Failure in this experiment is determined by observing the physical failure of the sock when "scratched" with a blunt glass rod.

10 The longer it takes before this crucial failure occurs, the more efficient the stabilizer system is. The days before failure are given in the following Tables IX, X, XI and XII for each of the stabilizer systems.

Table IX:

Days before failure

Stabilizer Quantity

WeatherOmeter NECK 1 0.30%

Phos I 0.09% 34 HA A 0.01% NECK 1 0.30%

Phos I 0.05% 38 HAA 0.05% _ HALS '0.30% AO A 0.05% o o

Phos I 0.05% HAA 0.05% _.

NECK 1 0.30% AO A 0.05% 28

Phos I 0.10%

Table X; ___

Days before failure

Stabilizer Quantity ^

WeatherOmeter NECK 2 0.30%

Phos I 0.09% 23 HAA 0.01% _ NECK 2 0.30%

Phos I 0.05% 30 HA A 0.05% • Table XI: 18 DK 175151 B1

Days before failure

Stabilizer Quantity

WeatherOmeter 5 --- NECK 3 030%

Phosl 0.09% 38 HA A 0.01% NECK 3 0.30%

Phos I 0.05% 37 10 HA A 0.05%

Table XII:, Days Before Forever in Stabilizer Quantity

WeatherOmeter 15 ---- NECK 2 0.05%

Phos Π 0.05% 9 In HA A 0.05% _ 20 Example 4: Long-term heat stability of polypropylene fibers.

For long-term heat aging at 120 ° C, other knitted socks of the stabilized polypropylene fibers are subjected to treatment in a forced draft oven equipped with a rotary carousel. Again, failure is determined as described above.

25 The longer it takes before such a crucial failure occurs, the more efficient the stabilizer system is. The experimental data are given in the following tables XIII, XIV and XV.

Table XIII: __ 30 .... _ - Days before failure

Stabilizer Amount p

at 120 ° C

NECK 1 030%

Phos I 0.09% 65 HA A 0.01% 35 HALSI 0.30%

Phos I 0.05% 61 HA A 0.05%

Table XIV: 19 DK 175151 B1 .. ,, _ Days before failure

Stabilizer Menade at 120 ° C 5 NECK 2 0.30%

Phosl 0.09% 40 HAA 0.01% - NECK 2 0.30%

Phosl 0.05% 72 HA A 0.05%

Table XV;

Days before failure

Stabilizer Menade

3 at 120 ° C

NECK 3 0.30%

Phosl 0.09% 68 HA A 0.01% NECK 3 0.30%

Phos I 0.05% 75 HA A 0.05% 20 __ I_

Examples 5-6 show that with respect to gas bleach resistance, the present stabilizer mixture 25 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 distinguished visually.

Example 5: Gas Bleach Resistance or Color Stability of Polypropylene Fibers.

Other knitted socks of the stabilized polypropylene fibers are exposed to nitrogen oxides in an exposure chamber using AATCC Test Method 23-1988, "Co lor fastness 35 to Burnt Gas Fumes" using 3 and 7 "cycles". The test samples are removed from the chamber and assessed for color changes (Delta E color scale) on an Applied Color Systems Model CS-5 colorimeter (D65 illuminance, 2 ° observation). Low Delta E values indicate less color and better stabilization. The test data are given in the following 5 Tables XVI, XVII, XVIII, XIX, XX, XXI and XXII.

Table XVI:

Delta E-color after bicycles Stabilizer Quantity - __ __3__7 NECK 1 030%

Phosl 0.09% 2.4 2.8 HA A 0.01% NECK 1 0.30%

Phos1 0.05% 23 2.9 HA A 0.05% NECK 1 030% AO A 0.05% c'j g 7

Phosl 0.09% V v HAA__0.01% ___ NECK 1 030% AO A 0.05%. ~ 51

Phosl 0.05% 4'3 0.1 HA A 0.05%

Table XVII; _________

Delta E-color after bicycles Stabilizer Quantity ----- "___3__7 NECK 1 0.05%

Phosl 0.09% 1.9 13 HA A__0.01% ___ HALSI 0.05%

Phos I 0.05% l, S 1.9 HA A 0.05% NECK 1 0.05% AO A 0.05% 00 57

Phos. 0.09% V

HAA__0.01% ___ NECK 1 0.05% AO A 0.05%. 50

Phosl 0.05% V ^ HA A 0.05% 211 175151 B1

Table XVIII:

Delta E-color 'after bikes

Stabilizer Amount --—- ___3__7 NECK 2 030%

Phosl 0.09% 1.6 1.5 HA A 0.01% NECK 2 0.30%

Phosl 0.05% 13 1.9 HA A 0.05% NECK 2 030% AO A 0.05% co

Phosl 0.09% HAA 0 0.01% AL NECK 2030% AO 0,0 0.05%. 0 ~ n

Phosl 0.05% A> y V

HA A 0.05%

Table XIX:

Delta E-color after bicycles Stabilizer Quantity ———— t ——— ___3__7 NECK 2 0.05%

Phosl 0.09% 1.6 1.5 HA A 0.01% NECK 2 0.05%

Phosl 0.05% 1.0 13 HA A 0.05% NECK 2 0.05% AO A 0.05% 00 .0

Phosl 0.09% HAA __ 0.01% __ NECK 2 0.05% AO A 0.05% 0 λ

Phos. 0.05% V

HA A 0.05%

Table XX: 22 DK 175151 B1

Delta E color 'after bicycles Stabilizer Quantity ----.-.- n.

___3__7 NECK 3 0.30%

Phos I 0.09% 2.4 2.3 HA A 0.01% NECK 3 0.30%

Phos I 0.05% 1.7 1.9 HA A 0.05% NECK 3 030% AO A 0.05% 48 6?

Phos I 0.09% -0.0 / HAA 0.01% HALS 3030% AO A 0.05% *, ς ~

Phos I 0.05% ^ HA A 0.05%

Table XXI:

Delta E-color after bicycles Stabilizer Quantity - - - __ __3__7 NECK 3 0.05%

Phos I 0.09% 1.9 1.6 HA A 0.01% NECK 3 0.05%

Phos I 0.05% 1.2 1.3 HA A 0.05% NECK 3 0.05% AO A 0.05% Δ n .o

Phos I 0.09%, U V

HAA__0.01% ___ NECK 3 0.05% AO A 0.05%. _ A (,

Phos I 0.05% 2'3 4'6 HA A 0.05%

Table XXII: 23 DK 175151 B1

Delta E-color after cycling _ Stabilizer Mass ---- ----. 3__7 NECK 2 0.05%

Phos 5 0.05% 1.5 1.8 HA A__0.05% ___ NECK 2 0.05% 10 AO A 0.05% in g o,

PhosH 0.05% * HA A 0.05% I 15

Example 6: Gas Bleaching Resistance or Color Stability of Polypropylene Fibers.

Other knitted socks of the stabilized polypropylene fibers are exposed to nitrogen oxides in an exposure chamber using AATCC Test Method 23-1988, "Colorfastness to Burnt Gas Fumes" for 3 "cycles". Experimental samples are removed from the chamber and assessed for color change (Delta E color scale) on an Applied Color Systems Model CS-5-color 25-meter (D65 illuminance, 2 ° observation). The test data are given in the following Tables XXIII, XXIV and XXV. Low Delta E values indicate less phase demand and better stabilization.

30

Table · XXIII: 24 DK 175151 B1

Stabilizer Amount of Delta E color after 3 cycles HALS 1 0.15%

Phosl 0.08% 6.9 AO A 0.04% NECK 1 0.15%

Phosl 0.08% 2.4 HA A 0.04% NECK 4 0.30%

Phosl 0.10% 2.7 AO A 0.05% NECK 4 0.30%

Phos I 0.05% 1.2 HA A 0.05% NECK 5 0.30%

Phosl 0.10% 3.2 AO A 0.05% NECK 5 0.30%

Phosl 0.05% 1.0 HA A 0.05% NECK 6 0.30%

Phosl 0.10% 2.1 AO A 0.05% NECK 6 0.30%

Phosl 0.05% 1.0 HA A 0.05% NECK 7 0.30%

Phos I 0.10% 2.2 AO A__0.05% __ NECK 7 0.30%

Phos I 0.05% 1.0 HA A 0.05%

Table XXIV: DK 175151 B1

Stabilizer Amount of Delta E color after 3 cycles 5 ----: - NECK 1 0.15%

Phos m 0.08% 5.6 AO A 0.04% __ NECK 1 0.15%

Phos ΠΙ 0.08% 3.8 10 HA A 0.04%

Table XXV:

Stabilizer Amount of Delta E color after 3 cycles 15 --- HALSI 0.15%

Phos IV 0.08% 4.8 AO A__0.04% __ HALSI 0.15%

Phos IV 0.08% 2.3 HA A 0.04%

Examination of the data set forth above shows that the present compositions containing other selected hindered amines, other phosphites and hydroxylamines provide excellent gas-bleaching resistance and color stability for polypropylene, a stability far superior to the stabilizer systems containing a phenolic antioxidant.

Example 7: Gas bleach resistance or color stability of polypropylene fibers.

Using the procedure of Example 6, the gas bleaching resistance or color stability of polypropylene fibers is measured when the fibers are protected by a binary system 35 of stabilizers containing an hindered amine and a hydroxylamine without the presence of any phosphite, compared with fibers. which further contains a phenolic antioxidant. The test data is given in the following tables XXVI, XXVII and XXVIII. Low Delta E values indicate less color and better stabilization.

Table XXVI; __

Stabilizer Amount of Delta E color after 3 cycles NECK 1 0.05%

Phosl 0.10% 4.7 10 AO A__0.05% NECK 1 0.05%. Λ HA A 0.10% x · 0 HALSI 0.05%

HA A 0.05% M

15 ---- J

Table XXVII: ___

Stabilizer Amount of Delta E color after 3 cycles 20 '- NECK 2 0.05%

Phosl 0.10% 4.1 AO A__0.05% __ NECK 2 0.05% n 0 HA A 0.10% NECK 2 0.05% HA A 0.05%

Table XXVIII: 3 ° stabilizer Amount of Delta E color after 3 cycles HALS 3 0.05%

Phosl 0.10% 4.4 AO A__0.05% __ 35 HALS 3 0.05% HA A 0.10% 1, υ HALS 3 0.05% λ q HA A 0.05% uy 27 DK 175151 B1

Examination of the above data shows that the binary compositions of the present invention containing selected hindered amines and hydroxylamines provide excellent gas bleaching resistance and color stability in connection with polypropylene, a resistance or stability which is far superior to the stabilizer systems which contains a phenolic antioxidant.

Example 8: Process Stabilization of Polypropylene Fibers 10 Melt flow differences resulting from insufficient processing or process stability are quite evident when the polypropylene is spun under demanding processing conditions. This is particularly evident when the polypropylene is spun at 302 ° C. The lower the melt flow rates, the more efficient the process stabilization efficiency of the stabilizer system (see also Example 1). The melt flow values of polypropylene spun at this temperature are given in the following Tables XXIX, XXX and XXXI.

20

Table XXIX:

Melt Flow Rate

Stabilizer Mix e Fiber spun at 302eC

HALS 1 0.05% 65 25 HALSI 0.05% 34

Phosphorus> 10% ____ NECK 1 0.05%

Phosl 0.10% 16 AO A__0.05% __ HALSI 0.05% HA A 0.05% 30 HALSI 0.05%

Phosl 0.05% 18 HA A__0.05% __ 35

Table XXX: 28 DK 175151 B1 - Melt flow rate

Stabilizer Amount of Fiber Spun at 302ec NECK 2 0.05% 56 NECK 2 0.05%

Phosl__0.10% NECK 2 0.05%

Phos I 0.10% AO A_ 0.05% NECK 2 0.05%

Phos I 0.05% 19 HA A 0.05% 15 --- NECK 2 0.05%, o HA A 0.05% 15

Table XXXI: 20. Melting speed of sound

Stabilizer Amount of Fiber 6 pounds

at 302βα I

NECK 3 0.05% 28 NECK 3 0.05% rt *

Phosl 0.10% --- NECK 3 0.05%

Phos I 0.10% 16 AO A__0.05% __ NECK 3 0.05%

Phos I 0.05% 17 30 HA A 0.05% NECK 3 0.05% 17

HA A 0.05% U

35 29 DK 175151 B1

The data in Tables XXIX, XXX and XXXI clearly show that in a conventional stabilizer system, a combination of phenolic antioxidant, hindered amine and phos- phite provides good processing or process stability. The removal of the phenolic antioxidant results in a significant loss of process or treatment stabilization. However, the replacement of a hydroxylamine instead of the phenolic antioxidant provides a process stabilization that is fully comparable to that provided with the phenolic antioxidant-phosphite system, both in the presence or absence of the phosphite component. Thus, the hindered amine plus hydroxylamine binary stabilizer system provides excellent thermal process stabilization for the polypropylene fibers.

Claims (14)

1. Stabilized polypropylene fibers which are free of or substantially free of any phenolic antioxidant and which have increased light stability, increased long-term heat stability and increased gas bleaching resistance, which fibers are stabilized with a mixture of a) a hindered amine selected from the group consisting of the polycondensation product of 4,4'-hexamethylene-bis- (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-tert-octylamino-s-triazine, po the leach condensation product of 1- (2-hydroxyethyl) - 2,2,6,6-tetramethyl-4-hydroxy-piperidine and succinic acid, N, N1, N ", N" '- tetrakis- [4,6-bis- (butyl) - (2,2,6,6-tetra-methylpiperidin-4-yl) -amino) -s-triazin-2-yl] -1,10-di-amino-4,7-diazadecane, the polycondensation product of 4, 4'-hexamethylene bis- (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-morpholino-s-triazine, poly- [methyl-3- (2,2,6, 6-tetramethylpiperidin-4-yl-oxy) -propyl] -siloxane, bis- (2,2,6,6-tetramethylpiperidin-4-yl) -cyclohexylene-dioxydimethylmalonate, 1,3,5-tr is- {N-cyclohexyl-N- [2- (2,2,6,6-tetramethyl-piperazin-3-one-4-yl) -ethyl] -amino-s-triazine, the polycondensation product of 4.41- hexamethylene bis- (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-cyclohexylamino-s-triazine and poly {N- [4,6-bis- (butyl- , 2,6,6-Tetramethyl-piperidin-4-yl) -amino] -s-triazin-2-yl] -1,4,7-triazanonan} -30 ω - N "- [4,6- bis- (butyl- (2,2,6,6-tetramethylpiperidin-4-yl) -amino) -s-triazin-2-yl] -amine, b) a phosphite or phosphonite selected from the group consisting of tris- (2 , 4-di-tert.butylphenyl) phosphite, 3,9-di- (2,4-di-tert.butylphenyl) -2,4,8,10-tetraoxa-3,9-diphospha [5.5] undecane , DK 175151 B1 2,2 ', 2 "-nitrilo tris- [ethyl - (3,3,5,51-tetra-tert-butyl-1,1'-biphenyl-2,2'-diyl) -phosphite), ethyl bis- (2,4-di-tert-butyl-6-methylphenyl) -phosphi t and tetrakis- (2,4-di-tert-butylphenyl) -4,4'-bis (diphenyl) and c) N, N -dialkylhydroxylamine product produced by the direct oxidation of N, N-di- (hydrogenated tallow) amine by oxidizing a solution of N, N-di-10 (hydrogenated tallow) amine in a lower alkanol solvent with a molar excess of 10-70% aqueous hydrogen peroxide solution at a temperature of 40-65 ° C where the weight ratio of the constituents (a) :( b) :( c) ranges from 1: 1: 1 to 100: 2: 1. The stabilized fiber of claim 1, wherein the component (a) is selected from the group consisting of the polycondensation product of 4,4'-hexamethylene bis - (amino-2,2,6,6-tetramethylpiperidine) and 2,4- dichloro-6-tert.octylamino-s-triazine, the polycondensation product of 1- (2-hydroxyethyl) -2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, N, N ', N ", N"' - tetrakis [4,6-bis- (butyl- (2,2,6,6-tetra-methylpiperidin-4-yl) -amino) -s-triazin-2-yl] -1,10-25 diamino-4, 7-Diazadecane, the polycondensation product of 4,4'-hexamethylene bis (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-morpholino-s-triazine, poly- [methyl-3- (2,2,6,6-tetramethylpiperidin-4-yloxy) -propyl) -siloxane, bis- (2,2,6,6-tetramethylpiperidin-4-yl) -cyclohexylene-dioxydimethylmalonate and 1,3,5- tris- {N-cyclohexyl-N- [2- (2,2,6,6-tetramethyl-piperazin-3-one-4-yl) -ethyl] -amino-s-triazine. The stabilized fiber of claim 1, wherein the component (b) is selected from the group consisting of DK 175151 B1 tris- (2,4-di-tert.butylphenyl) phosphite, 3.9-di- (2,4-di- tert.butylphenyl) -2,4,8,10-tetraoxa-3,9-diphospha [5.5] undecane, 2,21,2 "-nitrilo-tris- [ethyl (3,3 ', 5,5'-tetra-tert butyl-1,1'-biphenyl-2,2'-diyl) phosphite] and ethyl bis (2,4-di-tert-butyl-6-methylphenyl) phosphite. The stabilized fiber of claim 1, wherein the weight ratio of constituents (a) :( b) :( c) ranges from 10: 1: 1 to 10: 2: 1. A stabilized fiber according to claim 1, wherein the amount of the mixture of stabilizers is from 0.05 to 5% by weight, based on the weight of the fibers. A method of increasing gas bleach resistance and reducing color formation in stabilized polypropylene fibers, without loss of any other stabilizing property, by incorporating a mixture of stabilizers according to claim 1 therein. 7. A method of increasing the resistance to degradation of polypropylene fibers due to exposure to UV irradiation, relative to the resistance obtainable by the use of conventional stabilizers alone, by incorporating therein a mixture of stabilizers according to claim 1. A method of increasing the thermal stability of polypropylene fibers relative to that obtainable by the use of conventional stabilizers alone, by incorporating therein a mixture of stabilizers according to claim 1. 9. Stabilized polypropylene fibers which are free of 30 or substantially free of any phenolic antioxidant and which have enhanced light stability, increased long-term heat stability and increased gas-bleaching resistance, which fibers are stabilized with a mixture of I) a hindered amine selected from the group consisting of the polycondensation product of 4,4'-hexamethylene bis- - (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-1-6-tert.octylamino-5-triazine , the polycondensation product of 1- (2-hydroxyethyl) - 2.2.6.6-tetramethyl-4-hydroxypiperidine and succinic acid, N, Ν ', N ", N" "- tetrakis- [4,6-bis- (butyl- (2) 2,6,6-Tetra-5-methylpiperidin-4-yl) -amino-5-triazin-2-yl] -1,10-diamino-4,7-diazadecane, the polycondensation product of 4,4'-hexamethylene -bis- (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-morpholino-s-triazine, poly- [methyl-3- (2,2,6,6-tetramethylpiperidine) 4-yloxy) propyl] siloxane, bis - (2,2,6,6-tetramethylpiperidin-4-yl) -cyclohexylene dioxydimethyl malonate, 1,3,5-tris- {N-cyclohexyl-N- [2- (2,2,6,6-tetramethyl-piperazin-3-one-4-yl) -ethyl] -amino-s- triazine and the polycondensation product of the 4,4'-hexamethylene bis- (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-cyclohexylamino-s-triazine and the II) Ν, dial-dialkylhydroxylamine product which is produced by the direct oxidation of N, N-di- (hydrogenated tallow) - amine by oxidation of a solution of N, N-di- (hydrogenated tallow) amine in a lower alkanol solvent with a molar excess of 10-70% aqueous hydrogen peroxide solution at a temperature of 40-65 ° C, where the weight ratio of constituents (I): (II) ranges from 100: 1 to 1: 2. The stabilized fiber of claim 9, wherein the component (I) is selected from the group consisting of the polycondensation product of 4,4'-hexamethylene bis-30 (amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro - 6-tert.octylamino-s-triazine, the polycondensation product of 1- (2-hydroxyethyl) - 2.2.6.6-tetramethyl-4-hydroxypiperidine and succinic acid and N, N ', N ", N"' - tetrakis [4.6 bis (butyl- (2,2,6,6-tetramethylpiperidin-4-yl) -amino) -s-triazin-2-yl] -1,10-diamino-4,7-diazadecane. DK 175151 B1 The stabilized fibers of claim 9, wherein the weight ratio of constituents (I): (II) is from 10: 1 to 1: 1. A stabilized fiber according to claim 9, wherein the amount of the mixture of stabilizers is from 0.05 to 5% by weight, 5 based on the weight of the fibers. A method of increasing gas bleach resistance and reducing color formation in stabilized polypropylene fibers without loss of any other stabilizing property, by incorporating therein a mixture of 10 stabilizers according to claim 9. A method of increasing the resistance to degradation of polypropylene fibers due to exposure to UV radiation, relative to the resistance obtainable by the use of conventional stabilizers alone, by incorporating therein a mixture of stabilizers according to claim 9. 25 30