Natural Grain Leather

Abstract

A leather finishing process in which, in pertinent part, a warm water milling step is added after the base coat is applied to “crust” leather and cured. The warm water contains at least one dye fixation agent including but not limited to about 0.1-2.0% by weight of formic acid. Moreover, the base coat itself is an aqueous base coat containing at least two polymers such as an acrylic salt or a polyurethane salt. Between the polymeric constituents of the base coat, the acid fixation agent, and the use of the warm water milling step after the base coat has been applied and dried, a surprisingly natural feel to the leather is attained without loss of excellent adhesion, wear-resistance and other properties when the leather is completely finished.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. application Ser. No. 10 / 682,689, filed Oct. 9, 2003, which claims the benefit of U.S. Provisional Application No. 60 / 418,785, filed Oct. 15, 2002, the entire contents of all of said applications is hereby incorporated by reference.BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to a new leather manufacturing process which gives an enhanced natural feel to automotive leather without sacrificing wear, abrasion-resistance, adhesion or other qualities essential to satisfying rigorous automotive leather specifications.

[0004] 2. Description of Related Art

[0005] Leather manufacturing is a technology which has developed over many centuries using cattle, goat, kid, sheep and lamb hides, and even horse, pig, kangaroo, deer, reptile, seal and walrus, among others. The properties of the leather end-product vary depending upon the type of hide as well as the method used to ...

Examples

example 1

[0061]Cattle hides were collected and treated from hair removal through tanning and retanning, toggling and drying to create crust leather. A base coat in the amount of 1.5-1.7 grams per square foot was applied to the surface of the crust leather and allowed to dry at about 75-100 degrees C. A thin layer of clear top coat was applied immediately over the base coat and likewise allowed to dry at about 75-100 degrees C. The hides were then loaded into a drum with 150% by weight 45 degree C. water and tumbled for an hour. The hides were then subsequently gently squeezed dry without rolling, toggled, milled for 8 hours without added water, staked, sprayed with top coat, allowed to dry, and treated with final staking and milling treatments to soften them. The resulting leather had a much softer, warmer hand and feel than traditional Nappa leather, displayed excellent “break” in the leather, and yet satisfied major automotive leather specifications in test results described below.

[0062]Th...

example 2

[0065]A quantity of hides were treated in exactly the same way, from hair removal to finishing, except that a warm water milling step was added after the base coat was applied to some of the hides and the remaining hides were base coated without a subsequent water milling step. The base coat enumerated in Example 1 was used in the amount of 3.0-3.5 grams per square foot of hide on all the hides; roughly double the amount of base coat as used in Example 1. Notwithstanding the additional amount of base coat, the hides that were warm water tumbled displayed significantly improved hand, feel, break (as judged in the half pipe test), softness and apparent warmth as compared to the hides that were not warm water milled. The hides which had been warm water milled subsequent to base coating also had a more pronounced visual appearance of leather grain and hair cells compared to the hides which had not been warm water milled.

example 3

[0066]Finished hides of four chrome-tanned prior art leathers (“Vision,”“New Frontier,”“Classique,”“Salon”), as well as a chrome-tanned leather of the present invention (“Prestige”), were subjected to volatile organic hydrocarbon (VOC) analysis in order to determine the total VOC content (mg / kg) of the leathers, using the Toyota Tedlar Bag Method. Of the five finished hides tested, “Prestige” had the lowest VOC content of 0.05 mg / kg. The other four prior art leathers had substantially higher VOC contents, ranging from 0.6 mg / kg up to 2.6 mg / kg.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. application Ser. No. 10 / 682,689, filed Oct. 9, 2003, which claims the benefit of U.S. Provisional Application No. 60 / 418,785, filed Oct. 15, 2002, the entire contents of all of said applications is hereby incorporated by reference.BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to a new leather manufacturing process which gives an enhanced natural feel to automotive leather without sacrificing wear, abrasion-resistance, adhesion or other qualities essential to satisfying rigorous automotive leather specifications.

[0004] 2. Description of Related Art

[0005] Leather manufacturing is a technology which has developed over many centuries using cattle, goat, kid, sheep and lamb hides, and even horse, pig, kangaroo, deer, reptile, seal and walrus, among others. The properties of the leather end-product vary depending upon the type of hide as well as the method used to ...

Examples

example 1

[0061]Cattle hides were collected and treated from hair removal through tanning and retanning, toggling and drying to create crust leather. A base coat in the amount of 1.5-1.7 grams per square foot was applied to the surface of the crust leather and allowed to dry at about 75-100 degrees C. A thin layer of clear top coat was applied immediately over the base coat and likewise allowed to dry at about 75-100 degrees C. The hides were then loaded into a drum with 150% by weight 45 degree C. water and tumbled for an hour. The hides were then subsequently gently squeezed dry without rolling, toggled, milled for 8 hours without added water, staked, sprayed with top coat, allowed to dry, and treated with final staking and milling treatments to soften them. The resulting leather had a much softer, warmer hand and feel than traditional Nappa leather, displayed excellent “break” in the leather, and yet satisfied major automotive leather specifications in test results described below.

[0062]Th...

example 2

[0065]A quantity of hides were treated in exactly the same way, from hair removal to finishing, except that a warm water milling step was added after the base coat was applied to some of the hides and the remaining hides were base coated without a subsequent water milling step. The base coat enumerated in Example 1 was used in the amount of 3.0-3.5 grams per square foot of hide on all the hides; roughly double the amount of base coat as used in Example 1. Notwithstanding the additional amount of base coat, the hides that were warm water tumbled displayed significantly improved hand, feel, break (as judged in the half pipe test), softness and apparent warmth as compared to the hides that were not warm water milled. The hides which had been warm water milled subsequent to base coating also had a more pronounced visual appearance of leather grain and hair cells compared to the hides which had not been warm water milled.

example 3

[0066]Finished hides of four chrome-tanned prior art leathers (“Vision,”“New Frontier,”“Classique,”“Salon”), as well as a chrome-tanned leather of the present invention (“Prestige”), were subjected to volatile organic hydrocarbon (VOC) analysis in order to determine the total VOC content (mg / kg) of the leathers, using the Toyota Tedlar Bag Method. Of the five finished hides tested, “Prestige” had the lowest VOC content of 0.05 mg / kg. The other four prior art leathers had substantially higher VOC contents, ranging from 0.6 mg / kg up to 2.6 mg / kg.

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