Patent GB-1024769-A (GB)
Title: Improvements in or relating to material comprising collagen fibres and the manufacture thereof
IPC: C14C13/00
Filed: 1963-01-29
Abstract: A process of forming material which can be used as a substitute for leather comprises the steps of applying to a non-woven intermeshed fibre mass so that it penetrates thereinto, an aqueous acidic suspension having a pH not higher than 3, of swollen distinct fine collagon fibres of microscopic size, reducing the acidity of the suspension in the fibre mass to a pH not lower than 3.5 and removing water from the swollen collagen fibres whereby the fibres reaggregate into a larger collagen fibre structure interspersed with the intermeshed fibres.  Preferably the pH of the suspension is 0.5 to 3 and the collagen fibres are between 0.001 and 4 millimetres in length.  The percentage of collagen fibres based on the total dry weight of collagen and non-collagenous fibre present may range from 5-90% and is desirably in the range 30-50%.  The suspension may contain a mixture in the ratio of from 2:1 to 1:2 parts by weight of collagen fibres having a formaldehyde content of from 0.1 to 0.4% and collagen fibres having a higher formaldehyde content e.g. 1.1% giving a resultant formaldehyde content of from 0.65 to 0.8% and a pH value of from 2 to 2.5.  With this mixture the suspension is said to penetrate the fibre batt effectively and to be retained effectively within the batt; the low formaldehyde content fibres serving as a carrier for the higher formaldehyde content fibres to aid in penetration whilst the higher formaldehyde content fibres impart the desired retention characteristics.  Further the suspension may comprise a mixture of tanned collagen fibres and gelatin in solution or tanned collagen fibres and a cationic surface active agent.  The process may further include the step of treating the reaggregated collagen fibres with a mineral tanning agent.  The non-woven intermeshed fibre materials may be nylon polyacrylic ester fibres, polyester fibres, polypropylene fibres, extruded cellulosic fibres, natural cotton or longer collagen fibrous material which has been treated e.g. by chrome tanning. Products having a higher collagen content at the surface may be formed by first treating the fibre batt with a collagen suspension having good penetrating ability and thereafter treating the surface of the batt with a suspension having a lower penetration ability.  The resultant product may be coated on one side with a solution in a lower alkyl alcohol of a soluble nylon, the alcohol allowed to evaporate and the surface perforated as by needling.ALSO:A process of forming material which can be used as a substitute for leather comprises the steps of applying to a non-woven intermeshed fibre mass so that it penetrates thereinto, an aqueous acidic suspension having a pH not higher than 3, of swollen distinct fine collagen fibres of microscopic size, reducing the acidity of the suspension in the fibre mass to a pH not lower than 3.5 and removing water from the swollen collagen fibres whereby the fibres reaggregate into a larger collagen fibre structure interspersed with the intermeshed fibres.  Preferably the pH of the suspension is 0.5 to 3 and the collagen fibres are between 0.001 and 4 millimetres in length.  The percentage of collagen fibres based on the total dry weight of collagen and non-collagenous fibre present may range from 5 to 90% and is desirably in the range 30-50%.  The suspension may contain a mixture in the ratio of from 2:1 to 1:2 parts by weight of collagen fibres having a formaldehyde content of from 0.1 to 0.4% and collagen fibres having a higher formaldehyde content e.g. 1.1% giving a resultant formaldehyde content of from 0.65 to 0.8% and a pH value of from 2 to 2.5.  With this mixture the suspension is said to penetrate the fibre batt effectively and to be retained effectively within the batt; the low formaldehyde content fibres serving as a carrier for the higher formaldehyde content fibres to aid in penetration whilst the higher formaldehyde content fibres impart the desired retention characteristics.  Further the suspension may comprise a mixture of tanned collagen fibres and gelatin in solution or tanned collagen fibres and a cationic surface active agent.  The process may further include the step of treating the reaggregated collagen fibres with a mineral tanning agent.  The non-woven intermeshed fibre materials may be nylon, polyacrylic ester fibres, polyester fibres, polypropylene fibres, extruded cellulosic fibres, natural cotton or longer collagen fibrous material which has been treated e.g. by chrome tanning. Products having a higher collagen content at the surface may be formed by first treating the fibre batt with a collagen suspension having good penetrating ability and thereafter treating the surface of the batt with a suspension having a lower penetration ability.  The resultant product may be coated on one side with a solution in a lower alkyl alcohol of a soluble nylon, the alcohol allowed to evaporate and the surface perforated as by needling.