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
• • 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
  • C08K13/00—Use of mixtures of ingredients not covered by one single of the preceding main groups, each of these compounds being essential
  • C08K13/02—Organic and inorganic ingredients

Definitions

• This invention relates to synthetic polyamide compositions, to processes for their production and to shaped articles, including textile fibres, made from such compositions.
• Polyamides such as polyhexamethylene adipamide and polycaprolactam, are widely used for many purposes because of their remarkable mechanical strength. Their main field of application is the production of synthetic fibres, but they also find increasing use in other branches for example, in the production of tools and machine parts.
• the excellent properties of these polyamides are, however, considerably impaired by their tendency to become yellow under various conditions in the presence of oxygen. The yellowing occurs, for example, when polyarnides are subjected to elevated temperatures, when they are repeatedly washed with hot water, and when they are exposed to light and then kept for some time in the dark.
• British Patent No. 652,947 proposes copper salts of mono-carboxylic acids together with diketones
• United States Patent No. 2,705,227 describes a combination of copper, inorganic near Lucerne, Switzer- altogether, Emmena Swiss body 3,260,697 Patented July 12, 1966 ice halogen salts, and phosphorus compounds
• German Auslegeschrift No. 1,111,376 mentions a mixture of cerium (III) and/ or titanium (Ill) salts and hypophosphoric acids.
• the present invention provides synthetic polyamide compositions, especially suitable for making textile fibres, which are substantially free from colour and possess a substantial stability against discolouration caused by heat and light.
• the expression free from colour is used herein to mean absence of any undesired colouration of the polyamide, but doesnot exclude colour intentionally produced by the addition of dyes or pigments.
• the synthetic polyamide compositions of the invention comprise a composite stabilizing agent consisting essentially of (l) a thermally stable phenol, (2) a salt or ester of an inorganic phosphorus oxy-acid, (3) a manganese salt, and (4) an organic carboxylic acid anhydride.
• a composite stabilizing agent consisting essentially of (l) a thermally stable phenol, (2) a salt or ester of an inorganic phosphorus oxy-acid, (3) a manganese salt, and (4) an organic carboxylic acid anhydride.
• phenols cannot be used as they are oxidized too quickly, but thermally stabilized phenols containing, e.g. one or more tertiary butyl groups such as 2,5-di-tert-butyl hydroquinone, 2,2 methyl-bis-(4-methyl-G-tert-butylQphenol), 2,2-methylene-bis-(4-ethyl-6-tert butyl-phenol), or 4,4ibutylidene bis(6-tert butyl-m-cresol) have been found to be very suitable.
• sodium hypophoshite and triphenyl phosphate which are both relaible, are preferred.
• manganous lactate manganous oxalate and manganous hypophosphite are very suitable.
• acid anhydride component benzoic acid anhydride and hexa-hydro-phthalic acid anhydride are very satisfactory.
• a further advantage of the invention is that these acid anhydrides, in addition to acting as stabilizers, act also as chain terminators for the polycondensation process for making the polyamides. They can, therefore, replace the acetic acid which is usually employed for this purpose.
• the conventional type of chain terminating mono-oarboxylic acid cannot (as shown in the Example 11 below) be used to replace component (4) in the stabilizing agent of the invention.
• the stabilizers have the further advantage that they work well in the presence of titanium dioxide, which is usually incorporated in polyamides as a delustering pigment and which is known to increase considerably their sensitivity to light. Dyeing and addition of optical brightening agents do not impair the effects of the stabilizer combination of this turbed by its presence in the polyamide.
• the excellent protection afforded by the new four-component stabilizer against heat is especially important in the textile industry, because polyamides are necessarily heated at several stages in the manufacture of textile fibres. Although poly-condensation is carried out in a nitrogen atmosphere, traces of oxygen are still present, and, in any case, oxidation is possible when the molten mass is discharged from an autoclave or extruded from a spinneret. Unprotected polyamide chips and fi'bres have, therefore, a distinct ivory colour, while compositions containing the four-component stabilizing agent of the present delustered. Further discolouration polyamides usually occurs in the dry heat-setting process, and this operation causes considerable yellowing of unprotected fibres and makes an additional bleaching treatment necessary.
• polyamide fibres and fabrics produced in accordance with the present invention do not need bleaching, that they possess and keep a bright, pure white, and that when dyed, they preserve a clear and distinct colour shade foils, tools, and many other goods.
• the four components of the stabilizing agent are incorporated in the polyamides during tion process of manufacture of the polyamides, and the stabilizers.
• the polyhexamethylene adipamide compositions are prepared as follows: A 50% aqueous solution of hexamethylene diamine adipate is evaporated until a concentration of 75 to is achieved and is then heated in stabilizers, of any optical brightening agents can take place at various stages during manufacture. In Examples I to III the phenolic compound, the phosphorus compound, and the manganese salt are mixed with the 50% solution of hexamethylene diamine adipate. The titanium dioxide, in the form of a 20% aqueous dispersion, and, if desired,
• the polycaprolactam composition is made by warming caprolactam to C., mixing it with 1% of water and heating it in an autoclave for 2 hours at 250 C. Then dioxide or optical brightening agents can take place at In Example IV the manganese salt are added to the caprolactam together with the 1% of water, and the carboxylic acid anhydride,
• fibres are melt-spun in the usual manner, and compared with containing no stabilizer ferent combinations of only three of the four stabilizers used in the present invention.
• the relative viscosity is determined at 25 C. on an 11% solution of the polyamide composition in 90% formic acid.
• the heating test is carried out with a Thermotest Rhodiaceta developed by Rhodiaceta S.A., Paris, and made by Societe pour la Difiusion dAppareils de Mesure et de Controle, S.A., Tassin-la-Demi-Lune, Rhone, France. In this test small hanks of yarn are brought into contact during 60 seconds with heated metal plates having a temperature between 210 and 240 C., after which the colour of the yarn is judged visually.
• fibres not containing an optical brightening agent are used, because these agents are decomposed by light and may become yellow themselves.
• the fibres are exposed to sunlight of an intensity equal to rating 7 of the blue standard, according to test 95810 of the Swiss Standards Institution (SNV), and subsequently kept in the dark for three months, after which the colours of the light-exposed and the unexposed fibres are compared.
• the polyamide chips obtained are pure white.
• Fibres made in the same manner, but without the addition of an optical brightening agent, are subjected to the irradiation test. Bothv the light-exposed and the unexposed fibres show the same whiteness.
• Fibres are made for comparison in the same manner containing 1.1% of titanium dioxide and only three stabilizers, i.e.:
• Example Ill Fibres are melt-spun from a polyamide composition made from 5 kg. of hexamethylene diamine adipate containing 1.1% of titanium dioxide, 0.1% of Uvitex MP, and, as stabilizers, 0.05% of 2,5-di-tert-butyl-hydroquinone, 0.25% of triphenyl phosphate, 0.01% of manganous oxalate, equal to 38 parts of manganese per million parts of polyamide, and 0.55 of hexahydrophthalic acid anhydride.
• the relative viscosity of the fibres is 34.5, their tensile strength 6.2 g./denier, and their elongation at break 24.1%.
• the colour of the fibres both before and after heating to 225 C. is a pure white.
• Example 1V Fibres are melt-spun from a polyamide composition made from 5 kg. of cap -rolactam containing as stabilizers 0.05% of 2,5-di-tert-butyl-hydroquinone, 0.1% of sodium hypophosphite, 0.01% of manganous oxalate, equal to 38 parts of manganese per million parts of polyamide, and 0.225% of benzoic acid anhydride.
• the relative. viscosity of the fibres is 28.5, their tensile strength 5.0 g./ denier, 'and their elongation at break 15.3%.
• the colour of the fibres both before and after heating to 210 C. or when subjected to the irradiation test is a pure white.
• Fibres made for comparison in the same manner containing 0.17 of acetic acid as chain terminator and no stabilizing agents are originally white, but become strongly yellow when heated to 210 C.
• Example V Fibres are melt-spun from a polyamide composition made from 1000 kg. of hexamethylene diamine adipate containing 1.9% of titanium dioxide and, as stabilizers, 0.05% of 2,2-methylene bis-(4-methyl-6-tert-butyl-phenol), 0.3% of triphenyl phosphate, 0.01% of manganous oxalate, equal to 38 parts of manganese per million pants of polyamide, and 0.4% of benzoic acid anhydride.
• the relative viscosity of the fibres is 36.6, their tensile strength 5.8 g./denier, and their elongation at break 31.1%.
• the colour of the fibres both before and after heating to 225 C. is a pure white. When the fibres are subjected to the irradiation test, both the light-exposed and the unexposed fibres show .the same whiteness.
• Example VI Fibres are melt-spun from a polyamide composition made from 1000 kg. of hexamethylene diamine adipate containing 1.9% of titanium dioxide and, as stabilizers, 0.05% of 4,4 bu tylidene bis-(6-tert-butyl-m-cresol), 0.3% of triphenyl phosphate, 0.01% of manganous oxalate, equal to 38 pants of manganese per million pants of polyamide, and 0.4% of benzoic acid anhydride.
• the relative viscosity of the fibres is 34.5, their tensile strength 7.2 g./denier, and their elongation at break 16.6%.
• the colour of the fibres both before and after heating to 225 C. or when subjected to the irradiation test is a pure white.
• Synthetic polyamide compositions which are substantially free from colour and of good stability against discoloration by heart and light, in which have been inpolycontden's-ation (1) between 0.02 and 0.2% of a thermally stable phenol containing at least one tertiary-butyl group selected from the class consisting of 2,S-di-tert-butyl-hydroquinone, 2,2-methylene-bis-(4-methyl-6-tert-butyl-phenol), 2,2 methylenebis-(4-ethyl-6- tert-butyl-phenol), and 4,4'-butylidene bis- (6-tert-butyl-m-cresol), (2) between 0.05 and 0.5% of a compound selected from the class which consists of salts and esters of inorganic phosphorus oxy-acids, (3) between 20 and 80 parts of manganese per million parts of said polyamide composition in the form of a compound selected from the class consisting of manganous lactate, manganous oxalate and manganous
• Synthetic polyamide textile fibres which are substantially firee from colour and of good stability against discoloration by heat and light, in which have been incorporated during polycondensation 1) between 0.02 and 0.2% of a thermally stable phenol containing at lea-st one tentiary-bu'tyl group selected from the class consisting of 2,S-di-tert-butyl-hydroquinone, 2,2-methylene-bis-(4-methyl-6-tert-bu.tyl-phenol), 2,2 methylenebis-(4ethyl-6- tert-butyl-phenol), and 4,4-butylidene bis- (6-tert-butyl-m-cresol), (2) between 0.05 and 0.5% of a compound selected from the class which consists of salts and estens of inorganic phosphorus oxy-acids, 3) between 20 and pants of manganese per million parts of consists and hexahydrophthalic on the total weight of References Cited by the Examiner UNITED STATE

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Citations (9)

• 0
  • NL NL122899D patent/NL122899C/xx active
  • BE BE625217D patent/BE625217A/xx unknown
  • NL NL285687D patent/NL285687A/xx unknown
• 1961
  • 1961-11-24 GB GB42177/61A patent/GB978595A/en not_active Expired
• 1962
  • 1962-11-21 US US239330A patent/US3260697A/en not_active Expired - Lifetime
  • 1962-11-22 ES ES282696A patent/ES282696A1/es not_active Expired
  • 1962-11-22 DE DE19621520785 patent/DE1520785A1/de active Pending
  • 1962-11-22 CH CH1369562A patent/CH431071A/de unknown
• 1966
  • 1966-11-09 NL NL6615793A patent/NL6615793A/xx unknown

Patent Citations (9)

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