Reconstituted leather product and process

Details Reconstituted leather product and process Reconstituted leather product and process

1999-06-04

2001-07-24

Theisen, Mary Lynn (Department: 1732)

Plastic and nonmetallic article shaping or treating: processes

Direct application of fluid pressure differential to...

Bulk deposition of particles by differential fluid pressure

C264S115000, C264S121000, C264S122000, C264S913000, C428S904000, C524S011000

Reexamination Certificate

active

06264879

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a reconstituted leather product and a process for producing a reconstituted leather product. More particularly, the invention relates to a dry process for forming a reconstituted leather product from leather fibers. The reconstituted leather product of the invention has desirable leather qualities, can be cut and sewn into leather products and is generally recyclable. The leather product of the invention can be reconstituted, that is, used as a starting material in the process of the invention.
BACKGROUND OF THE INVENTION
Conventional processes for producing tanned leather and tanned leather goods generate considerable waste material. Scraps from cut leather, wet blue shavings from the tanning process, and other leather waste from conventional leather processes is usually bulked and transported to landfills. Disposal of leather waste in this way is environmentally undesirable and can be costly to the leather producer. In addition, chromed tanned leather and chemicals used to produce leather products can be unwanted in landfill operations.
Current approaches to recycling leather waste materials include producing fertilizers by extracting portions of slurried leather. Considerable waste, requiring disposal, can be a byproduct of this extraction process.
Processes for producing a moldable mat from fibrous wood products are well known. One such process is disclosed in U.S. Pat. No. 4,418,031 to Doerer et al. In the Doerer et al. process, cellulose fibers are mixed with synthetic fibers, the synthetic fibers are melted, and then solidified to form a cohesive mat of cellulose and synthetic fibers. This process includes dry blending the fibers together, passing this blend through a former, curing the blend in an oven, and molding the cured blend into a shaped article.
It has been found that utilizing a dry process for making a fibrous mat is environmentally advantageous and relatively time and energy efficient. Typically, if a dry process is used for fibrous mat preparation and processing, then there is no slurry or waste byproduct that has to be discarded.
It should be highly desirable to develop a process for making a reconstituted leather product using limited amounts of water. It would also be highly desirable for this same process to recycle all types of scrap and waste leather and hide materials. Preferably, a process is developed such that the reconstituted leather product is continuously recyclable, that is, the reconstituted product at the end of its useful life is capable of entering the preparation process of the invention as a starting material.
Further, it is desirable to produce a reconstituted leather product having the strength and pliability of real leather. The reconstituted leather product can also have the ability to be cut and sewn into leather-like products. It is also desirable to produce a reconstituted leather product having similar physical properties when compared with natural, unrecycled leather.
SUMMARY OF THE INVENTION
Applicant has discovered a process for producing a reconstituted leather product by mixing leather fibers and other leather materials with synthetic fibers and resin in a relatively dry forming process. This process produces a reconstituted leather product that when finished can have the desired qualities of strength and pliability similar to natural, unrecycled leather.
The invention provides a reconstituted leather product and a process for making that product while recycling all types of leather scrap and waste. The process of the invention utilizes scrap leather from all aspects of the tanning and leather product producing process, including discarded and/or reconstituted leather products. The final reconstituted leather product of the invention can be finished to have the look and physical properties of real leather. The reconstituted leather of the invention is pliable and can be cut and sewn into leather-like products.
Preparing the reconstituted leather product of the invention involves combining leather fibers, bonding fibers, resins, and optionally other additives, such as additional fibers, wetting agents, colors and perfumes. Preferably all of these components are recyclable.
The term “leather fibers,” as used herein, refers to fibers of natural leather, fibers of reconstituted leather, and/or mixtures thereof As used herein, the term “leather materials” refers to materials of natural leather, of reconstituted leather, and/or mixtures thereof including waste materials generated in each step of the leather production process.
In the process of the invention, natural and/or reconstituted leather scrap and waste materials are reduced to leather fibers, mixed with bonding fibers, resin and optionally other additives in an essentially dry process to produce a reconstituted leather product. The reconstituted leather product has a distinct woven fiber appearance and can be soft and pliable when finished to possess the look of natural leather. Preferably, the reconstituted leather product is recyclable.
Applicants have found that this type of dry process is inappropriate for some types of leather processing and/or recycling, because the dry leather fibers or other leather materials can easily crumble or burn during the process. If the leather materials crumble or burn during the recycling process, the resulting reconstituted leather product's physical properties are diminished.
As used herein, the term “essentially dry” refers to a process in which the leather material used throughout the reconstitution process has a moisture content of about 25% by weight or less. A wet leather slurry is typically not formed in the process of the invention as compared with other attempts to recycle leather products.
Leather products made by the process of the invention are woven in appearance, and can be cut, sewn and shaped into products commonly formed of leather and/or synthetic leather materials including: insoles, mid soles and linings for shoes, boots, skates and other types of footwear; leather-like pads, liners, panels, supports or outside finishes for use in the apparel, furniture, packaging, automobile, computer and other industries.
The reconstituted leather product of the invention is preferably continuously recyclable. That is, the product produced by the method of the invention can be reduced to fibers and may again be used in the process of the invention, once it has outlived its useful life.
These and other features of the invention will become more apparent upon reading the following detailed description of the invention and preferred embodiments.


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