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
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/20—Carboxylic acid amides

Definitions

• composition which comprises polyacrylonitrile and a stabilising agent which comprises maleamic acid or an N-substituted maleamic acid in which the N-substitutants are methyl, ethyl and phenyl groups or the amide group;
• the invention is concerned with the stabilisation of polyacrylonitrile :and particularly with stabilisation against discolouration on exposure to heat.
• polyacrylonitrile I mean both homopolymers of acrylonitrile and also copolymers containing at least 80 percent by weight of acrylonitrile units.
• Such copolymers may be the products of copolymerisation with acrylonitrile of such other monomers :as styrene, methyl acrylate, itaconic acid, methallyl sulphonic acid and its salts, vinyl acetate and vinyl pyridine.
• the invention is particularly applicable to copolymers containing 90 to 95 percent by weight of acrylonitrile units.
• Thermal discolouration of polyacrylonitrile has been known for some time.
• the discolouration is believed to be caused by conjugation of carbon-nitrogen double bonds derived from the cyanide groups.
• proposals for the prevention of this discolouration include, for example, the addition to polymer solutions of reducing agents, which may be organic or inorganic in nature. It has been found that some of the additives employed for the prevention of thermal discolouration interfere with other properties of the polyacrylonitrile, for example the dyeability may be impaired.
• the invention comprises a polyacrylonitrile article containing a stabilising agent which is maleamic acid or an N-substituted maleamic acid.
• a stabilising agent which is maleamic acid or an N-substituted maleamic acid.
• the N-substituents of N-substituted maleamic acids suitable as stabilising agents may be, for example, -CH -C H CO.NH CO.NHR', CO.NR'R -C H or C H R'.
• Examples of N-substituted maleamic acids which may be employed are Maleuric acid CI-I-CO.NHOONH2 CH-COOH.
• CH-COOH and Polyacrylonitrile articles to which the invention relates may take any of the usual forms.
• such an article may be a filament, a staple fibre, a thread, a fabric or a film.
• Such polyacrylonitrile articles may be used in conjunction with articles consisting of other material.
• a yarn or fabric may be a blend of polyacrylonitrile fibres with other fibres.
• the stabilising agent employed in the invention may be incorporated in the polyacrylonitrile article by known methods.
• the most common method of application is by addition of the stabilising agent to a spinning solution 3,417,049 Patented Dec. 17, 1968 of the polyacrylonitrile. This method may be employed Where suitable, but when the solvent is an inorganic salt solution, addition of the stabilising agent thereto can lead to contamination of the solvent if a recycling process is used.
• the stabilising agent should be applied to the polyacrylonitrile article after the article has been formed.
• one method of applying the stabilising agent consists in immersing the article in 'a solution of the agent followed by removal of excess liquor from the article and by drying. In suitable cases this process may be operated continuously. It is preferred that the impregnation of the polyacrylonitrile article with the solution of the stabilising agent should be performed before the article has been dried for the first time since its production.
• the amount of the stabilising agent which is incorporated in the polyacrylonitrile may vary according to such factors as the nature of the article, the degree of stabilisation required and the particular stabilising agent used. Normally, however, it is not necessary to employ more than 5 percent by weight of the compound on the article although more than this, up to 10 percent or higher, may be used. It is preferred to use a quantity of the order of 0.2 ml percent by weight.
• the stabilising agent in a neutralised or partially neutralised form.
• the polyacrylonitrile is dyeable with basic dyes.
• treatment with unneutralised stabilising agent considerably affects the dye uptake but that the effect may be mitigated by use of the agent in a solution which has been partially neutralised with sodium hydroxide, or other base.
• the invention includes polyacrylonitrile articles containing the salts of maleamic acid or N-substituted maleamic acids.
• Example 1 A 200 filament, 600 denier, bright polyacrylonitrile tow was passed continuously, before it had been dried after production, through a bath containing a 1 percent by weight aqueous solution of maleuric acid, which had been neutralised to pH 4.5 with sodium hydroxide. After im' mersion in the bath, the tow was padded to percent take-up and dried in an oven at 80 C.
• Example 5 which were stretched and dried and tested to measure their tability to thermal discolouration.
• the fibres were heated for one hour in an oven at 130 C. during which the fibre yellowness was found to rise from 0.075 to 0.297 compared with a final fibre yellowness of 0.35 for untreated fibre.
• N-substituted maleamic acid in which the N-substituent is selected from the group consisting Of CH3, 'C2H5, -CONH2, and C6H5;
• composition as claimed in claim 1 which contains from 0.1 to 5 percent by weight of the stabilising agent.
• composition as claimed in claim 1 which contains from 0.2 to 1 percent by weight of stabilising agent.

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Artificial Filaments (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Coloring (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=10112849

Family Applications (1)

Country Status (7)

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Citations (3)

• 1965
  • 1965-05-03 GB GB18462/65A patent/GB1138945A/en not_active Expired
• 1966
  • 1966-04-29 US US546207A patent/US3417049A/en not_active Expired - Lifetime
  • 1966-05-02 SE SE5962/66A patent/SE314824B/xx unknown
  • 1966-05-02 NL NL6605901A patent/NL6605901A/xx unknown
  • 1966-05-03 BE BE680408D patent/BE680408A/xx unknown
  • 1966-05-03 ES ES0326259A patent/ES326259A1/es not_active Expired
  • 1966-05-03 DE DE19661669381 patent/DE1669381A1/de active Pending

Patent Citations (3)

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