A method for manufacturing hybrid-natural leather having excellent appearance quality and good durability such as light resistance, water resistance, elongation and abrasion resistance is provided. Particularly, the fiber layer having a similar structure to the natural leather is introduced to the natural leather and the natural leather and the fiber layer are bonded and fused with each other under a specific condition to manufacture hybrid-natural leather having excellent durability while preventing wrinkles, stretching, and the like from being generated.

The present invention provides a method of manufacturing leather, which not only significantly suppresses the occurrence of adhesive wrinkling and boarding/alighting wrinkling when used for an automobile seat, for example, but also exhibits appropriate flexibility. The present invention is a method of manufacturing leather including a pretreatment step, a tanning step, a retanning step, and a drying and finishing step in this order, the retanning process including, in the following order, subjecting a shaving leather obtained from the tanning process to a stage of performing treatment using a predetermined retanning agent and a predetermined resin, a stage of performing treatment using a predetermined retanning agent, a predetermined resin, and a predetermined fatliquoring agent, and a stage of performing treatment using a predetermined resin and a predetermined fatliquoring agent, and the drying in the drying and finishing process including, in the following order, subjecting a leather obtained from the retanning process to a stage of drying under reduced pressure under predetermined conditions and a step of drying at atmospheric pressure under predetermined conditions.

The present invention provides a method of manufacturing leather, which not only significantly suppresses the occurrence of adhesive wrinkling and boarding/alighting wrinkling when used for an automobile seat, for example, but also exhibits appropriate flexibility. The present invention is a method of manufacturing leather including a pretreatment step, a tanning step, a retanning step, and a drying and finishing step in this order, the retanning process including, in the following order, subjecting a shaving leather obtained from the tanning process to a stage of performing treatment using a predetermined retanning agent and a predetermined resin, a stage of performing treatment using a predetermined retanning agent, a predetermined resin, and a predetermined fatliquoring agent, and a stage of performing treatment using a predetermined resin and a predetermined fatliquoring agent, and the drying in the drying and finishing process including, in the following order, subjecting a leather obtained from the retanning process to a stage of drying under reduced pressure under predetermined conditions and a step of drying at atmospheric pressure under predetermined conditions.

The present invention discloses a process for preparing a flame-retardant, lightfast, low fogging and degradable car seat leather wherein ammonia salt deliming is replaced with an ammonia free one, tetrakis hydroxymethyl phosphonium sulfate and the flame-retardant starchy leather surfactant are used as the tanning agents to replace the conventional chrome tanning agent, hot water washing is used to reduce the fogging value of the seat leather, the flame-retardant performance is enhanced by combination of retanning, greasing and coating, the lightfast material is applied to enhance the lightfastness of the coating and the spray coating is replace with the roller coating to lower the consumption of the paints.

The present invention discloses a process for preparing a flame-retardant, lightfast, low fogging and degradable car seat leather wherein ammonia salt deliming is replaced with an ammonia free one, tetrakis hydroxymethyl phosphonium sulfate and the flame-retardant starchy leather surfactant are used as the tanning agents to replace the conventional chrome tanning agent, hot water washing is used to reduce the fogging value of the seat leather, the flame-retardant performance is enhanced by combination of retanning, greasing and coating, the lightfast material is applied to enhance the lightfastness of the coating and the spray coating is replace with the roller coating to lower the consumption of the paints.

A process for tanning leathers including a pre-tanning step and a tanning step is provided. In the pre-tanning step leathers are treated with a cationic active agent including a quaternized ester of a fatty acid and triethanolamine, or mixtures thereof and, subsequently, with an anionic active agent including tannins vegetable extracts and a natural or synthetic dispersant selected from the group consisting of lignosulfonates, distillation stillages, sulfonated disulfonic polymers, sulfonated naphthalene polymers or mixtures thereof, to obtain leathers with a shrinkage temperature of at least 65 C. The pre-tanning and tanning steps do not include treatment with aldehydes or aldehyde donor compounds and/or with metal salts.

A process for tanning leathers including a pre-tanning step and a tanning step is provided. In the pre-tanning step leathers are treated with a cationic active agent including a quaternized ester of a fatty acid and triethanolamine, or mixtures thereof and, subsequently, with an anionic active agent including tannins vegetable extracts and a natural or synthetic dispersant selected from the group consisting of lignosulfonates, distillation stillages, sulfonated disulfonic polymers, sulfonated naphthalene polymers or mixtures thereof, to obtain leathers with a shrinkage temperature of at least 65 C. The pre-tanning and tanning steps do not include treatment with aldehydes or aldehyde donor compounds and/or with metal salts.

A method for tanning an animal skin may include: (a) putting the skin in contact with a first tanning bath including at least one dialdehyde of general formula OCH(CH.sub.2).sub.nHCO, wherein n is 0 or an integer number greater than or equal to 1 and less than or equal to 8, and wherein the first tanning bath has a pH greater than or equal to 1 and less than or equal to 5; (b) bringing the pH of the first tanning bath to a pH greater than 5 and less than 8; and/or (c) repeating one or more times the steps (a) and (b) on the skin coming from the step (b) using a second or further tanning bath. In the first, second, and further tanning baths, surfactants may be present in a total quantity less than 0.05% by weight relative to a pelt weight of the skin.

A method for tanning an animal skin may include: (a) putting the skin in contact with a first tanning bath including at least one dialdehyde of general formula OCH(CH.sub.2).sub.nHCO, wherein n is 0 or an integer number greater than or equal to 1 and less than or equal to 8, and wherein the first tanning bath has a pH greater than or equal to 1 and less than or equal to 5; (b) bringing the pH of the first tanning bath to a pH greater than 5 and less than 8; and/or (c) repeating one or more times the steps (a) and (b) on the skin coming from the step (b) using a second or further tanning bath. In the first, second, and further tanning baths, surfactants may be present in a total quantity less than 0.05% by weight relative to a pelt weight of the skin.