CA2367926A1 - Composition for producing molded parts which contains ground leather, and method for producing or using said molded parts - Google Patents
Composition for producing molded parts which contains ground leather, and method for producing or using said molded parts Download PDFInfo
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- CA2367926A1 CA2367926A1 CA002367926A CA2367926A CA2367926A1 CA 2367926 A1 CA2367926 A1 CA 2367926A1 CA 002367926 A CA002367926 A CA 002367926A CA 2367926 A CA2367926 A CA 2367926A CA 2367926 A1 CA2367926 A1 CA 2367926A1
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- Prior art keywords
- leather
- ground stock
- binder
- composition
- binders
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
- C08L75/04—Polyurethanes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J11/00—Recovery or working-up of waste materials
- C08J11/04—Recovery or working-up of waste materials of polymers
- C08J11/06—Recovery or working-up of waste materials of polymers without chemical reactions
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L89/00—Compositions of proteins; Compositions of derivatives thereof
- C08L89/04—Products derived from waste materials, e.g. horn, hoof or hair
- C08L89/06—Products derived from waste materials, e.g. horn, hoof or hair derived from leather or skin, e.g. gelatin
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2110/00—Foam properties
- C08G2110/0016—Foam properties semi-rigid
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2110/00—Foam properties
- C08G2110/0033—Foam properties having integral skins
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Dermatology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Treatment And Processing Of Natural Fur Or Leather (AREA)
- Synthetic Leather, Interior Materials Or Flexible Sheet Materials (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
The invention relates to a composition that contains leather and/or rubber particles, binders and softeners. The composition is characterized by the properties of natural leather, that is, favorable absorption of humidity, release of humidity, retention of humidity and a long-wearing and flexible behavior while it is easy to process to molded parts. The composition is processed to molded parts by (a) mixing the binder with the softener and the leather and/or rubber particles; (b) transferring the mixture to a mold that is preheated to 120 ~C to 160 ~C; (c) heat-treating the mixture in the mold for 3 to 20 minutes at maximally 160 ~C and (d) cooling and removing the molded part from the mold. The molded parts are useful as components for producing shoes and as sound-absorbing elements for the construction or automotive industry.
Description
Composition For Producing Molded Parts Which Contains Ground Leather, And Method For Producing~or Using Said Molded Parts The object of the present invention are compositions containing leather and/or rubber particles, binders and plastifiers for the preparation of formed articles as well as methods for the preparation of said formed articles. Another object of the present invention is the preparation of said formed articles for use as shoe components and as sound insulation elements for the construction and automobile industries.
Description of the background art/Field of the invention During the last decade, several applications have gained patent protection which related to the use of tanned leather scrapings. A major part of these processes aim at the preparation of various formed articles after appropriate size reduction of the leather scrapings wherein a binder is used.
Some of these processes describe the behaviour of the leather scrapings obtained after size reduction. This material is not uniform and its processing is difficult because depending on the starting leather scrapings and the type of size reduction the material contains powders and fibres of different sizes and nature/origin. Due to its structure, the material tends to form a fluffy pelt which impedes its further processing.
However, although these adverse properties of the leather scrapings are not pointed out in the Hungarian patents, the disadvantages become obvious when the ground stock is provided and because of the difficulties in obtaining a uniform binder coating. Although the patent application No.
Description of the background art/Field of the invention During the last decade, several applications have gained patent protection which related to the use of tanned leather scrapings. A major part of these processes aim at the preparation of various formed articles after appropriate size reduction of the leather scrapings wherein a binder is used.
Some of these processes describe the behaviour of the leather scrapings obtained after size reduction. This material is not uniform and its processing is difficult because depending on the starting leather scrapings and the type of size reduction the material contains powders and fibres of different sizes and nature/origin. Due to its structure, the material tends to form a fluffy pelt which impedes its further processing.
However, although these adverse properties of the leather scrapings are not pointed out in the Hungarian patents, the disadvantages become obvious when the ground stock is provided and because of the difficulties in obtaining a uniform binder coating. Although the patent application No.
- 2 -HU T/40 316 (December 28, 1986) states that a "homogenous"
leather ground stock free form knots is obtained, a mixing period of 2-3 hours is required to ensure a uniform mixing quality.
Although there are several exceptions (e.g. EP 0 92 594 A1, PCT/EP93/01812), patent applications from other countries pay more attention to the behaviour of the leather ground stock.
In patent No. US 5 346 934, the amount of the fines fraction is limited to a particular value by means of air separation.
Several patents from other countries (EP 0 256 663 A2, US 5 134 178, and US 5 272 190) state that the adhesion of the leather ground stock is reduced and its wettability is increased by means of a steam treatment. In some of the patented processes (EP 0 089 029 A2, CH 17 828/71/, and CH 17 040/72/), in order to obtain the final product the leather ground stock is processed by means of a wet felting process known from the papermaking industry.
On the other hand, patent US 4 380 474 states that in the case of polymeric diisocyanates it is possible to perform the application of appropriate binders by means of spraying.
Since the adhesive tendency of fibre ground stocks is w~ell-known in the textile industry, methods have been developed for the preparation of thick and thin felts. Some are of the opinion that the adhesive tendency is dependent on the surface of the elementary fibres while others think that it depends on the electrostatic charging of the fibre elements.
As illustrated by the discussion above and supported by our experience, a uniform application of the binder -particularly at binder concentrations below 50~ by wt. - may CA 02367926 2001-10-17 _ 3 necessitate complex installations and expensive preparative operations which in the end may have an effect on the competitiveness of the final product on the market.
Those patent applications which relate to the preparation of formed final products suggest the use of numerous natural as well as synthetic adhesives as the binders. Besides the diisocyanates already mentioned above there is often used an ethylene-vinyl acetate copolymerizate (US 5 272 190, US 5 346 934), and the leather ground stock is frequently admixed into rubber mixtures (US 5 272 190, US 5 346 394). The patent No.
US 4 497 871 recommends to use a crude rubber solution as the binder. Other patent applications additionally mention polyvinyl acetate (HU 204 548 B) and polyvinyl chloride (HU
206 738 B) as binders.
Form stabilisation of the of the products prepared from the leather ground stock is carried out after curing of the binder which may be achieved by drying, removal of the solvents, cooling, polycondensation, and polyaddition. The process parameters strongly depend on the properties of the binder and the ground stock, and the parameters of the leather ground stock are taken into consideration by only some of the patents - in a very limited manner. This mad result from the fact that most of the patents treat the leather ground stock as if it were a filler and assume to have been successful if the properties of the binder are not unacceptably deteriorated by the addition of the leather ground stock.
- 3a- -EP 0 456 264 A2 relates to a leather in the form of a powder wherein the mean particle size of the leather particles is 7 um with a maximal deviation of 3 uzn.
US 3,116,200 describes a reconstituted leather product which contains tanned leather fibres together with polyvinyl acetate and a plastifying composition. With respect to its size the leather material is as uniform as possible.
FR 1,033,397 describes a product containing leather scrapings and a plastifying agent in an amount of 33~.
GB 586,232 relates to the reuse of leather scrapings wherein tanned leather is pretreated by a treatment with 1~ sulfuric acid which further contains sodium hypophosphite. The maximal leather content in the composition is 20~ in the form of dust.
DE 865366 C is directed to a process for the preparation of a leather substitute wherein first a pulp is formed which contains fibre bunches and which is subjected to a chemical treatment, and the pulp thus prepared is mixed with an 1 emulsion comprising a mixture of a vinyl resin and an anthracene oil. The product thus obtained is formed into sheets by means of pressure and dried.
WO 90/00184 describes a polymer composition containing rubber discards or leather fibres wherein the composition contains surfactants and wherein 10-50$ of the leather or rubber particles have a size of < 1 mm.
Most of the prior art compositions use leather only as~a~
filler, and the mechanical and physico-chemical properties of the (natural) leather are altered due to the processing. In particular a treatment at higher temperatures leads to a partial or complete denaturation of the natural leather whereby its suppleness, flexibility, as well as its capability to absorb water are lost.
Therefore, in contrast to the practice used heretofore, the object underlying the present invention is to provide a composition containing leather and/or rubber particles and binders wherein - in the presence of leather particles - the advantageous properties of the natural leather, i.e.
appropriate moisture pick-up and loss, moisture holding, and strain recovery behaviour, are preserved and utilised in the final product, and wherein the composition may be easily processed to obtain formed articles.
It is another object of the present invention to provide a method for the preparation of formed articles from such compositions wherein the advantageous properties of the natural leather are preserved and utilised in the formed articles.
It is another object of the present invention to use the formed articles prepared according to the present invention as shoe components and as sound insulation elements for' construction industry and automobile industry, respectively.
According to the present invention, leather of natural structure refers to leather which - in contrast to imitation leather - is of natural origin, and to leather which has not been completely ground to form powder and/or has not been completely dewatered or denatured, respectively, by means of a thermal treatment.
Brief description of the invention According to the present invention, the above-mentioned objects have been achieved by providing a composition containing leather and/or rubber particles, characterised in that the composition contains 30-89.5 by wt. leather and/or rubber particles;
10-60~ by wt. binders; and 0.5-20~ by wt. plastifiers.
A preferred composition contains:
30-89.50 by wt. leather ground stock;
10-60$ by wt. binders; and 0.5-20~ by wt. plastifiers.
A further preferred composition contains:
30-85~ by wt. leather ground stock;
10-60o by wt. binders and 2-20o by wt. plastifiers.
Another preferred composition contains: a 30-89.5 by wt. leather ground stock;
10-49.5 by wt. binders; and 0.5-20~ by wt. plastifiers.
According to the present invention it is further preferred to replace the leather ground stock partially or completely, preferably to 50 to 1000, by rubber granulates.
Moreover, the present invention provides a method forwthe preparation of formed articles from such compositions wherein the method comprises the following steps of:
(a) mixing the binder with the plastifier and the leather and/or rubber particles (according to methods known per se) ;
(b) introducing the mixture into a compression mould preheated to 120°C-160°C, preferably 140°C-155°C~
(c) conducting a heat treatment for 3-20 minutes inside the compression mould which has a maximal temperature of 160°C; and (d) cooling and removing the formed article from the compression mould.
The method according to the present invention comprises a compression operation which may by performed effectively in a temperature range adapted to the properties of leather with minimal running and short operation times and which enables the preparation of formed final products having different properties depending on the ratio of binder to leather ground stock.
A feature of the method according to the present invention is that it comprises pretreatment operations, i.e. grinding and binder application, which can be conducted easily thereby greatly simplifying industrial application.
The purpose of conducting the grinding is not to prepare a homogenous ground stock or one which varies within a narrow range. Instead of a uniform physical (formal) appearance there are prepared uniform mixtures of fractions having the same form. The higher adhesion properties of the light _ 7 _ fractions, the so-called leather fluff, are utilised for the application of the binder. Therefore, the leather will not be completely ground to form powder so that the original leather structure is preserved.
The method according to the present invention is characterised by the fact that the properties of the binder are modified by addition of plastifying agents so that it is possible to largely preserve the original properties of the heat sensitive leather ground stock. This is done by preventing the decomposition process and minimising the loss of water. As the binders, there may be used thermoplastic as well as specific three-dimensionally crosslinking polymers wherein the use of waste recycling products may present an economical advantage while generally no disadvantages with respect to quality have been observed.
In the composition according to the present invention, preferably polar plastifiers are contained, preferably phosphoric esters or phthalates.
The method according to the present invention is environmentally friendly, does not cause a pollution of environmental water and air while it is possible to regrind the hard scrapings.
The oily leather recycling product obtained has a specific density of 0.7-1.3 g/cm3 and contains leather chippings of several mm in size which are embedded in the binder.
The final products may be used in the following two fields of use which, however, should not be construed as a limitation of the use for other applications.
If used in the shoe industry, the final products may be advantageously used with a Content of leather ground stock of 30-75 ~ by wt. by themselves or in combination with d.~fferent materials.
According to the present invention, the leather ground stock may be replaced, partially or completely, by rubber granulates, for example from fabrication waste or from the reuse of automobile tyres, so that compressed bodies, boards, and/or formed articles may be formed which comprise rubber in a high proportion. The amount of leather ground stock replaced may be varied within broad limits, and there may be replaced for example 50-100 of the leather ground stock by rubber granules.
As acoustic insulation materials, the final products may be used with a leather ground stock content of 50-90 ~ by wt. by themselves or in combination with other materials.
Another feature of our method is that it may be easily coupled to textiles, paper, natural leather and/or with coverings made of synthetic material which is identical or similar to the binder.
Detailed description of the invention In different patent applications, there are described numerous size reduction devices for the processing of tanned leather scrapings. In this respect, the dry and wet size reduction devices are considered as same. Accordingly, beater slushing devices, grinding gears with blades and hammers, as well as other grinding machines, respectively, have been mentioned in the applications.
In the method according to the present invention, the grinding of the leather scrapings is performed in a dry operation in a manner that the ground stock obtained contains natural leather chippings with natural structure having a grain size of 1-10 mm (preferably 4-8 mm) in a proportion of 50-80% by wt. in the light leather fluff fraction which is randomly distributed within the irregular content of leather powder and leather fibre residues. The balance, i.e. 50-20%
by wt. comprises powder < 1 mm and leather fibre residues >
mm.
According to the present invention, it is possible to replace the above-mentioned leather ground stock or the leather particles, respectively, partially or completely by rubber granulates. In this manner there may be prepared for example compressed bodies, boards and/or formed articles wherein the amount of replaced leather preferably is 50 to 100%. The rubber granulates may be synthetic and/or natural rubber. The use of rubber granules from fabrication waste or from rubber derived from the reuse of automobile tyres is preferred.
The binder used may be a thermoplastic or weakly cross-linked polymer, preferably polyvinyl chloride, ethylene vinyl acetate copolymer, thermoplastic rubber, and weakly cross-linked polyurethane, which is present in the form of a powder and may be partially molten in a temperature range below 160°C. Preferred binders for use are waste ground stocks of the soft cellular materials used in the furniture and automobile industries and the soft integral skin foams used in the shoe and automobile industries, respectively. It is required for the binder ground stock that 100% of the material pass a 1.25 mm screen according to DIN standard while 15% of the material are held back by a 0.63 screen according to DIN standard. Generally, the required grinding fineness may be achieved by using simple methods. It is further preferred according to the present invention to employ PVC powders, preferably semi-hard PVC powder as the binder ground stock.
The binder ground stock is mixed free from knots with a chlorinated or unchlorinated phosphoric ester in an amount of 2-20 o by wt., mostly 5-15~ by wt., based on the total composition, or with other plastifiers adapted to the binder.
Afterwards, the leather ground stock described above is added. The amount of leather ground stock may be varied with respect to the binder within broad limits, i.e. in the range of 50 to 89.5 ~ by wt. (0.5 to 8.95 times the amount of binder). A preferred ratio is 100 to 400 by wt. of leather ground stock (1-4 times the amount of binder) as based on the weight of the binder. After some minutes of mixing a preproduct is obtained wherein the natural leather particles and the granules of the binder material are randomly distributed within the fluffy leather pelt. The polar plastifying agent acts to greatly improve the adhesion of the binder granules to the leather fluff so that the material may be transferred from the mixing device to the compression mould with a minimal loss of binder, and may be removed and proportioned, respectively, without a change in the ratio.
The forming operation may be carried out by means of a heat treatment for 3-20 minutes depending on the thickness of the product inside the compression mould which has been preheated to 120-160°C, preferably to 140-155°C.
Depending on the composition, the properties of the finished product may vary within a broad range, and for modification of the properties the above-mentioned introduction of w coverings of textile, paper, and a synthetic~material which may be coupled to the binder provide further possibilities.
Examples Each of the following examples relates to the use of a leather recycling product. However, thereby it is note intended to limit the scope of the present invention.
Particularly, there is also comprised according to the present invention a partial or complete replacement of the leather by rubber granulates.
19t Example Preparation of a 300 x 150 x 5 mm leather recycling product having a specific density of 0.8 g/cm3 and a woven textile covering having a weight of 20 g/m2 on one surface 54 g ground stock of 54 g semi-hard polyurethane integral skin foam which shows the above-described parameters with respect to its grain size and may also be prepared from production or recycled waste are mixed free from knots with g tris-(chloroisopropyl)-phosphate plastifier.
Subsequently, 108 g of leather ground stock are added which shows the size and. composition parameters mentioned above.
After some minutes of stirring the leather ground stock absorbs the binder ground stock so that the two fraction do not separate and cannot be separated, respectively.
This wadding-like material is introduced into the compression mould preheated at 155°C after the textile covering has been spreaded inside the mould, and after closing of the device a heat treatment for 8 minutes is carried out. After cooling of the device, the prepared article may be removed.
2nd Example Preparation of a 300 x 150 x 10 mm leather recycling product having a specific density of 1.0 g/cm3 without covering The method of production is identical to that described in the 1st example except that for the preparation of the final product 350 g leather ground stock, 85 g semi-hard foam ground stock, and 15 g plastifying agent are used. The mixture is immediately transferred to the lower surface of the compression mould, and the heat treatment period is extended by 10 minutes.
3rd Example Preparation of 300 x 150 x 10 mm leather recycling product having a specific density of 1.2 g/cm3 without covering This method of production is a variation of the one described in the 2nd example wherein 175 g of semi-hard PVC powder are used as the binder which was wetted by 20 g dioctylphth~late serving as the plastifier.
4th Example Preparation of a 300 x 150 x 5 mm leather recycling product having a specific density of 1.1 g/cm3 and a combination of paper and aluminium foil on one surface 100 g thermoplastic rubber powder showing the grain size parameters as described above are mixed free from knots with
leather ground stock free form knots is obtained, a mixing period of 2-3 hours is required to ensure a uniform mixing quality.
Although there are several exceptions (e.g. EP 0 92 594 A1, PCT/EP93/01812), patent applications from other countries pay more attention to the behaviour of the leather ground stock.
In patent No. US 5 346 934, the amount of the fines fraction is limited to a particular value by means of air separation.
Several patents from other countries (EP 0 256 663 A2, US 5 134 178, and US 5 272 190) state that the adhesion of the leather ground stock is reduced and its wettability is increased by means of a steam treatment. In some of the patented processes (EP 0 089 029 A2, CH 17 828/71/, and CH 17 040/72/), in order to obtain the final product the leather ground stock is processed by means of a wet felting process known from the papermaking industry.
On the other hand, patent US 4 380 474 states that in the case of polymeric diisocyanates it is possible to perform the application of appropriate binders by means of spraying.
Since the adhesive tendency of fibre ground stocks is w~ell-known in the textile industry, methods have been developed for the preparation of thick and thin felts. Some are of the opinion that the adhesive tendency is dependent on the surface of the elementary fibres while others think that it depends on the electrostatic charging of the fibre elements.
As illustrated by the discussion above and supported by our experience, a uniform application of the binder -particularly at binder concentrations below 50~ by wt. - may CA 02367926 2001-10-17 _ 3 necessitate complex installations and expensive preparative operations which in the end may have an effect on the competitiveness of the final product on the market.
Those patent applications which relate to the preparation of formed final products suggest the use of numerous natural as well as synthetic adhesives as the binders. Besides the diisocyanates already mentioned above there is often used an ethylene-vinyl acetate copolymerizate (US 5 272 190, US 5 346 934), and the leather ground stock is frequently admixed into rubber mixtures (US 5 272 190, US 5 346 394). The patent No.
US 4 497 871 recommends to use a crude rubber solution as the binder. Other patent applications additionally mention polyvinyl acetate (HU 204 548 B) and polyvinyl chloride (HU
206 738 B) as binders.
Form stabilisation of the of the products prepared from the leather ground stock is carried out after curing of the binder which may be achieved by drying, removal of the solvents, cooling, polycondensation, and polyaddition. The process parameters strongly depend on the properties of the binder and the ground stock, and the parameters of the leather ground stock are taken into consideration by only some of the patents - in a very limited manner. This mad result from the fact that most of the patents treat the leather ground stock as if it were a filler and assume to have been successful if the properties of the binder are not unacceptably deteriorated by the addition of the leather ground stock.
- 3a- -EP 0 456 264 A2 relates to a leather in the form of a powder wherein the mean particle size of the leather particles is 7 um with a maximal deviation of 3 uzn.
US 3,116,200 describes a reconstituted leather product which contains tanned leather fibres together with polyvinyl acetate and a plastifying composition. With respect to its size the leather material is as uniform as possible.
FR 1,033,397 describes a product containing leather scrapings and a plastifying agent in an amount of 33~.
GB 586,232 relates to the reuse of leather scrapings wherein tanned leather is pretreated by a treatment with 1~ sulfuric acid which further contains sodium hypophosphite. The maximal leather content in the composition is 20~ in the form of dust.
DE 865366 C is directed to a process for the preparation of a leather substitute wherein first a pulp is formed which contains fibre bunches and which is subjected to a chemical treatment, and the pulp thus prepared is mixed with an 1 emulsion comprising a mixture of a vinyl resin and an anthracene oil. The product thus obtained is formed into sheets by means of pressure and dried.
WO 90/00184 describes a polymer composition containing rubber discards or leather fibres wherein the composition contains surfactants and wherein 10-50$ of the leather or rubber particles have a size of < 1 mm.
Most of the prior art compositions use leather only as~a~
filler, and the mechanical and physico-chemical properties of the (natural) leather are altered due to the processing. In particular a treatment at higher temperatures leads to a partial or complete denaturation of the natural leather whereby its suppleness, flexibility, as well as its capability to absorb water are lost.
Therefore, in contrast to the practice used heretofore, the object underlying the present invention is to provide a composition containing leather and/or rubber particles and binders wherein - in the presence of leather particles - the advantageous properties of the natural leather, i.e.
appropriate moisture pick-up and loss, moisture holding, and strain recovery behaviour, are preserved and utilised in the final product, and wherein the composition may be easily processed to obtain formed articles.
It is another object of the present invention to provide a method for the preparation of formed articles from such compositions wherein the advantageous properties of the natural leather are preserved and utilised in the formed articles.
It is another object of the present invention to use the formed articles prepared according to the present invention as shoe components and as sound insulation elements for' construction industry and automobile industry, respectively.
According to the present invention, leather of natural structure refers to leather which - in contrast to imitation leather - is of natural origin, and to leather which has not been completely ground to form powder and/or has not been completely dewatered or denatured, respectively, by means of a thermal treatment.
Brief description of the invention According to the present invention, the above-mentioned objects have been achieved by providing a composition containing leather and/or rubber particles, characterised in that the composition contains 30-89.5 by wt. leather and/or rubber particles;
10-60~ by wt. binders; and 0.5-20~ by wt. plastifiers.
A preferred composition contains:
30-89.50 by wt. leather ground stock;
10-60$ by wt. binders; and 0.5-20~ by wt. plastifiers.
A further preferred composition contains:
30-85~ by wt. leather ground stock;
10-60o by wt. binders and 2-20o by wt. plastifiers.
Another preferred composition contains: a 30-89.5 by wt. leather ground stock;
10-49.5 by wt. binders; and 0.5-20~ by wt. plastifiers.
According to the present invention it is further preferred to replace the leather ground stock partially or completely, preferably to 50 to 1000, by rubber granulates.
Moreover, the present invention provides a method forwthe preparation of formed articles from such compositions wherein the method comprises the following steps of:
(a) mixing the binder with the plastifier and the leather and/or rubber particles (according to methods known per se) ;
(b) introducing the mixture into a compression mould preheated to 120°C-160°C, preferably 140°C-155°C~
(c) conducting a heat treatment for 3-20 minutes inside the compression mould which has a maximal temperature of 160°C; and (d) cooling and removing the formed article from the compression mould.
The method according to the present invention comprises a compression operation which may by performed effectively in a temperature range adapted to the properties of leather with minimal running and short operation times and which enables the preparation of formed final products having different properties depending on the ratio of binder to leather ground stock.
A feature of the method according to the present invention is that it comprises pretreatment operations, i.e. grinding and binder application, which can be conducted easily thereby greatly simplifying industrial application.
The purpose of conducting the grinding is not to prepare a homogenous ground stock or one which varies within a narrow range. Instead of a uniform physical (formal) appearance there are prepared uniform mixtures of fractions having the same form. The higher adhesion properties of the light _ 7 _ fractions, the so-called leather fluff, are utilised for the application of the binder. Therefore, the leather will not be completely ground to form powder so that the original leather structure is preserved.
The method according to the present invention is characterised by the fact that the properties of the binder are modified by addition of plastifying agents so that it is possible to largely preserve the original properties of the heat sensitive leather ground stock. This is done by preventing the decomposition process and minimising the loss of water. As the binders, there may be used thermoplastic as well as specific three-dimensionally crosslinking polymers wherein the use of waste recycling products may present an economical advantage while generally no disadvantages with respect to quality have been observed.
In the composition according to the present invention, preferably polar plastifiers are contained, preferably phosphoric esters or phthalates.
The method according to the present invention is environmentally friendly, does not cause a pollution of environmental water and air while it is possible to regrind the hard scrapings.
The oily leather recycling product obtained has a specific density of 0.7-1.3 g/cm3 and contains leather chippings of several mm in size which are embedded in the binder.
The final products may be used in the following two fields of use which, however, should not be construed as a limitation of the use for other applications.
If used in the shoe industry, the final products may be advantageously used with a Content of leather ground stock of 30-75 ~ by wt. by themselves or in combination with d.~fferent materials.
According to the present invention, the leather ground stock may be replaced, partially or completely, by rubber granulates, for example from fabrication waste or from the reuse of automobile tyres, so that compressed bodies, boards, and/or formed articles may be formed which comprise rubber in a high proportion. The amount of leather ground stock replaced may be varied within broad limits, and there may be replaced for example 50-100 of the leather ground stock by rubber granules.
As acoustic insulation materials, the final products may be used with a leather ground stock content of 50-90 ~ by wt. by themselves or in combination with other materials.
Another feature of our method is that it may be easily coupled to textiles, paper, natural leather and/or with coverings made of synthetic material which is identical or similar to the binder.
Detailed description of the invention In different patent applications, there are described numerous size reduction devices for the processing of tanned leather scrapings. In this respect, the dry and wet size reduction devices are considered as same. Accordingly, beater slushing devices, grinding gears with blades and hammers, as well as other grinding machines, respectively, have been mentioned in the applications.
In the method according to the present invention, the grinding of the leather scrapings is performed in a dry operation in a manner that the ground stock obtained contains natural leather chippings with natural structure having a grain size of 1-10 mm (preferably 4-8 mm) in a proportion of 50-80% by wt. in the light leather fluff fraction which is randomly distributed within the irregular content of leather powder and leather fibre residues. The balance, i.e. 50-20%
by wt. comprises powder < 1 mm and leather fibre residues >
mm.
According to the present invention, it is possible to replace the above-mentioned leather ground stock or the leather particles, respectively, partially or completely by rubber granulates. In this manner there may be prepared for example compressed bodies, boards and/or formed articles wherein the amount of replaced leather preferably is 50 to 100%. The rubber granulates may be synthetic and/or natural rubber. The use of rubber granules from fabrication waste or from rubber derived from the reuse of automobile tyres is preferred.
The binder used may be a thermoplastic or weakly cross-linked polymer, preferably polyvinyl chloride, ethylene vinyl acetate copolymer, thermoplastic rubber, and weakly cross-linked polyurethane, which is present in the form of a powder and may be partially molten in a temperature range below 160°C. Preferred binders for use are waste ground stocks of the soft cellular materials used in the furniture and automobile industries and the soft integral skin foams used in the shoe and automobile industries, respectively. It is required for the binder ground stock that 100% of the material pass a 1.25 mm screen according to DIN standard while 15% of the material are held back by a 0.63 screen according to DIN standard. Generally, the required grinding fineness may be achieved by using simple methods. It is further preferred according to the present invention to employ PVC powders, preferably semi-hard PVC powder as the binder ground stock.
The binder ground stock is mixed free from knots with a chlorinated or unchlorinated phosphoric ester in an amount of 2-20 o by wt., mostly 5-15~ by wt., based on the total composition, or with other plastifiers adapted to the binder.
Afterwards, the leather ground stock described above is added. The amount of leather ground stock may be varied with respect to the binder within broad limits, i.e. in the range of 50 to 89.5 ~ by wt. (0.5 to 8.95 times the amount of binder). A preferred ratio is 100 to 400 by wt. of leather ground stock (1-4 times the amount of binder) as based on the weight of the binder. After some minutes of mixing a preproduct is obtained wherein the natural leather particles and the granules of the binder material are randomly distributed within the fluffy leather pelt. The polar plastifying agent acts to greatly improve the adhesion of the binder granules to the leather fluff so that the material may be transferred from the mixing device to the compression mould with a minimal loss of binder, and may be removed and proportioned, respectively, without a change in the ratio.
The forming operation may be carried out by means of a heat treatment for 3-20 minutes depending on the thickness of the product inside the compression mould which has been preheated to 120-160°C, preferably to 140-155°C.
Depending on the composition, the properties of the finished product may vary within a broad range, and for modification of the properties the above-mentioned introduction of w coverings of textile, paper, and a synthetic~material which may be coupled to the binder provide further possibilities.
Examples Each of the following examples relates to the use of a leather recycling product. However, thereby it is note intended to limit the scope of the present invention.
Particularly, there is also comprised according to the present invention a partial or complete replacement of the leather by rubber granulates.
19t Example Preparation of a 300 x 150 x 5 mm leather recycling product having a specific density of 0.8 g/cm3 and a woven textile covering having a weight of 20 g/m2 on one surface 54 g ground stock of 54 g semi-hard polyurethane integral skin foam which shows the above-described parameters with respect to its grain size and may also be prepared from production or recycled waste are mixed free from knots with g tris-(chloroisopropyl)-phosphate plastifier.
Subsequently, 108 g of leather ground stock are added which shows the size and. composition parameters mentioned above.
After some minutes of stirring the leather ground stock absorbs the binder ground stock so that the two fraction do not separate and cannot be separated, respectively.
This wadding-like material is introduced into the compression mould preheated at 155°C after the textile covering has been spreaded inside the mould, and after closing of the device a heat treatment for 8 minutes is carried out. After cooling of the device, the prepared article may be removed.
2nd Example Preparation of a 300 x 150 x 10 mm leather recycling product having a specific density of 1.0 g/cm3 without covering The method of production is identical to that described in the 1st example except that for the preparation of the final product 350 g leather ground stock, 85 g semi-hard foam ground stock, and 15 g plastifying agent are used. The mixture is immediately transferred to the lower surface of the compression mould, and the heat treatment period is extended by 10 minutes.
3rd Example Preparation of 300 x 150 x 10 mm leather recycling product having a specific density of 1.2 g/cm3 without covering This method of production is a variation of the one described in the 2nd example wherein 175 g of semi-hard PVC powder are used as the binder which was wetted by 20 g dioctylphth~late serving as the plastifier.
4th Example Preparation of a 300 x 150 x 5 mm leather recycling product having a specific density of 1.1 g/cm3 and a combination of paper and aluminium foil on one surface 100 g thermoplastic rubber powder showing the grain size parameters as described above are mixed free from knots with
3 g dioctylphthalate as the plastifier. Then, this material is admixed with 250 g of leather ground stock which shows the size and composition parameters mentioned above. After some minutes of stirring and after the leather ground stock has absorbed the binder ground stock, the wadding-like material is introduced into the compression mould preheated at 145°C
into which the paper/aluminium combination has already been introduced with the paper side facing the mould opening. The material was spread uniformly inside the device, and after closing of the device was kept at the above-mentioned temperature for 6 minutes. After cooling of the apparatus, the final product is removed.
5"' Example Preparation of a 300 x 150 x 10 mm leather recycling product having a specific density of 1.15 g/cm3 without covering The method of production is identical to that described in example 4 except that in this case 100 g ethylene vinyl acetate copolymer were used as the binder material which had been wetted before with 10 g dioctylphthalate. Furthermore, the heat treatment was carried out for 8 minutes at 155°C.
Because no covering is used, the mixture is transferred directly to the lower surface of the compression mould.
into which the paper/aluminium combination has already been introduced with the paper side facing the mould opening. The material was spread uniformly inside the device, and after closing of the device was kept at the above-mentioned temperature for 6 minutes. After cooling of the apparatus, the final product is removed.
5"' Example Preparation of a 300 x 150 x 10 mm leather recycling product having a specific density of 1.15 g/cm3 without covering The method of production is identical to that described in example 4 except that in this case 100 g ethylene vinyl acetate copolymer were used as the binder material which had been wetted before with 10 g dioctylphthalate. Furthermore, the heat treatment was carried out for 8 minutes at 155°C.
Because no covering is used, the mixture is transferred directly to the lower surface of the compression mould.
Claims (27)
1. Composition containing leather ground stock and binders wherein said composition contains:
30-89.5% by wt. leather ground stock;
10-60% by wt. binders; and 0.5-20% by wt. plastifiers, wherein the leather ground stock consists of leather particles having a natural structure and wherein 50-80 % by wt. of the leather particles have a grain size of 1 - 10 mm, preferably 4 - 8 mm and 50 - 20 % by wt. are powder < 1mm and leather fibre residues > 10 mm.
30-89.5% by wt. leather ground stock;
10-60% by wt. binders; and 0.5-20% by wt. plastifiers, wherein the leather ground stock consists of leather particles having a natural structure and wherein 50-80 % by wt. of the leather particles have a grain size of 1 - 10 mm, preferably 4 - 8 mm and 50 - 20 % by wt. are powder < 1mm and leather fibre residues > 10 mm.
2. Composition according to claim 1 wherein the leather ground stock is partially replaced by rubber granulates.
3. Composition according to one or more of the preceding claims wherein as the binders said composition contains thermoplastic polymers and/or weakly cross-linked polymers.
4. Composition according to one or more of the preceding claims wherein as the thermoplastic polymers said composition contains weakly crosslinked PU foams.
5. Composition according to one or more of the preceding claims wherein as the binder said composition contains waste ground stock from the soft foams used in the furniture and automobile industries or from the soft integral skin foams used in the shoe and automobile industries.
6. Composition according to one or more of the preceding claims wherein the binder has a melting point below 160°C.
7. Composition according to one or more of the preceding claims wherein said composition contains a binder ground stock in the form of a powder wherein 100 of the powder particles pass a 1.25 mm screen according to DIN standard while 15% of the particles are held back by a 0.63 screen according to DIN standard.
8.. Composition according to one or more of the preceding claims wherein the binder ground stock is PVC powder, preferably semi-hard PVC powder.
9. Composition according to one or more of the preceding claims wherein as the plastifying agents said composition contains polar plastifiers, preferably phosphoric esters or phthalates.
10. Composition according to claim 9 wherein as the plastifying agent said composition contains tris-(chloroisopropyl)phosphate and/or dioctylphthalate.
11. Method for the preparation of formed articles from compositions according to one or more of the preceding claims wherein said method comprises the following steps of:
(a) mixing the binder with the plastifier and the leather ground stock obtained by dry grinding (according to methods known per se);
(b) introducing the mixture into a compression mould preheated to 120°C-160°C, preferably 140°C-155°C;
(c) conducting a heat treatment for 3-20 minutes in the compression mould which has a maximal temperature of 160°C; and (d) cooling and removing the formed article from the compression mould.
(a) mixing the binder with the plastifier and the leather ground stock obtained by dry grinding (according to methods known per se);
(b) introducing the mixture into a compression mould preheated to 120°C-160°C, preferably 140°C-155°C;
(c) conducting a heat treatment for 3-20 minutes in the compression mould which has a maximal temperature of 160°C; and (d) cooling and removing the formed article from the compression mould.
12. Method according to claim 11 wherein first the binder is admixed with the plastifying agent and afterwards the mixture obtained is admixed with the leather ground stock.
13.. Method according to any of claims 11 or 12 wherein the formed article is prepared with a covering made of textiles, paper, natural leather, metals, synthetic materials or combinations thereof by introducing into the compression mould a covering of one or more of the above-mentioned materials prior to introduction of the composition.
14. Method according to any of claims 11 to 13 wherein thermoplastic polymers and/or weakly cross-linked polymers are used as the binders.
15. Method according to any of claims 11 to 14 wherein three-dimensionally crosslinked PU foams are used as binders.
16. Method according to any of claims 11 to 15 wherein waste ground stock from the soft foams used in the furniture and automobile industries or from the soft integral skin foams used in the shoe and automobile industries are used as the binder.
17. Method according to any of claims 11 to 16 wherein the binder has a melting point below 160°C.
18. Method according to any of claims 11 to 17 wherein a binder ground stock is used wherein 100% of the particles pass a 1.25 mm screen according to DIN standard while 15%
of the particles are held back by a 0.63 screen according to DIN standard.
of the particles are held back by a 0.63 screen according to DIN standard.
19. Method according to any of claims 11 to 18 wherein polar plastifiers, preferably phosphoric esters or phthalates, are used as the plastifying agents.
20.. Method according to any of claims 11 to 19 wherein tris-(chloroisopropyl)phosphate and/or dioctylphthalate is used as the plastifying agent.
21. Use of formed articles prepared according to any of claims 11 to 20 as an acoustic insulation material in the construction and automobile industries or as a shoe component wherein the formed article comprises 30-89.5% by wt. leather ground stock;
10-60% by wt. binders; and 0.5-20% by wt. plastifiers;
and optionally is prepared with a covering made of textiles, paper, natural leather, metals, synthetic materials or combinations thereof.
10-60% by wt. binders; and 0.5-20% by wt. plastifiers;
and optionally is prepared with a covering made of textiles, paper, natural leather, metals, synthetic materials or combinations thereof.
22. Use of formed articles prepared according to any of claims 11 to 20 as an acoustic insulation material in the construction and automobile industries wherein the formed article comprises an amount of leather ground stock of 50-89.5% by wt. and optionally is prepared with a covering made of textiles, paper, natural leather, metals, synthetic materials or combinations thereof.
23. Use of formed articles prepared according to any of claims 11 to 20 as a shoe component wherein the formed article comprises an amount of leather ground stock of 30-75% by wt. and optionally is prepared with a covering made of textiles, paper, natural leather, metals, synthetic materials or combinations thereof.
24. Method according to any of claims 14 to 23 wherein tris-(chloroisopropyl)phosphate and/or dioctylphthalate is used as the plastifying agent.
25. Use of formed articles prepared according to any of claims 14 to 24 as an acoustic insulation material in the construction and automobile industries or as a shoe component wherein the formed article comprises 30-89.5% by wt. leather ground stock;
10-60% by wt. binders; and 0.5-20% by wt. plastifiers;
and optionally is prepared with a covering made of textiles, paper, natural leather, metals, synthetic materials or combinations thereof.
10-60% by wt. binders; and 0.5-20% by wt. plastifiers;
and optionally is prepared with a covering made of textiles, paper, natural leather, metals, synthetic materials or combinations thereof.
26. Use of formed articles prepared according to any of claims 14 to 24 as an acoustic insulation material in the construction and automobile industries wherein the formed article comprises an amount of leather ground stock of 50-89.5% by wt. and optionally is prepared with a covering made of textiles, paper, natural leather, metals, synthetic materials or combinations thereof.
27. Use of formed articles prepared according to any of claims 14 to 24 as a shoe component wherein the formed article comprises an amount of leather ground stock of 30-75% by wt. and optionally is prepared with a covering made of textiles, paper, natural leather, metals, synthetic materials or combinations thereof.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE1999119111 DE19919111C2 (en) | 1999-04-27 | 1999-04-27 | Composition containing leather pulp for the production of moldings, process for the production or use of the moldings |
| DE19919111.5 | 1999-04-27 | ||
| PCT/EP2000/003759 WO2000064982A1 (en) | 1999-04-27 | 2000-04-26 | Composition for producing molded parts which contains ground leather, and method for producing or using said molded parts |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2367926A1 true CA2367926A1 (en) | 2000-11-02 |
Family
ID=7906029
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002367926A Abandoned CA2367926A1 (en) | 1999-04-27 | 2000-04-26 | Composition for producing molded parts which contains ground leather, and method for producing or using said molded parts |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP1177257A1 (en) |
| AR (1) | AR023611A1 (en) |
| BR (1) | BR0010048A (en) |
| CA (1) | CA2367926A1 (en) |
| DE (1) | DE19919111C2 (en) |
| WO (1) | WO2000064982A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10060246B4 (en) * | 2000-12-05 | 2011-05-05 | Süße, Harald, Dipl.-Ing. | Process for the processing of animal meal and animal debris for the production of leather fiber composites with addition of chrome shavings (CFS) and mineral fibers (TLV process) |
| DE10320061B4 (en) * | 2003-05-06 | 2005-12-22 | Bader Gmbh & Co. | Process for the production of a material using leather waste and molded part produced therewith |
| DE102008017960A1 (en) * | 2008-04-08 | 2009-10-15 | Bader Gmbh & Co. Kg | Flat material web for use as coating on car seats, hand tools, and consumer goods, and as interior carpeting for automobiles or commercial vehicles or interior decoration, has fiber layer made of leather fibers and binding agent |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH107214A (en) * | 1923-12-01 | 1924-10-01 | Louis Benoit Albert | Process for the production of objects from synthetic material. |
| DE865366C (en) * | 1941-04-07 | 1953-02-02 | Salpa Francaise | Process for the manufacture of a leather substitute |
| GB586232A (en) * | 1944-07-25 | 1947-03-12 | Bermondsey Leather Company Ltd | Process for utilising waste leather |
| US2464282A (en) * | 1945-11-24 | 1949-03-15 | Abrahams Morton | Utilization of leather waste |
| FR1033397A (en) * | 1951-03-05 | 1953-07-10 | Industrial process for manufacturing flat or relief parts in composition containing either leather, textile, asbestos, wood flour, cork waste | |
| US3116200A (en) * | 1957-01-08 | 1963-12-31 | Swift & Co | Reconstituted leather product and method of making |
| JP2526045B2 (en) * | 1986-03-17 | 1996-08-21 | 出光石油化学株式会社 | Method for manufacturing leather-like material |
| HU212122B (en) * | 1988-06-29 | 1996-02-28 | Volk | Polimer compositions containing waste rubber and/ore waste leather as filler |
| AU640005B2 (en) * | 1990-05-11 | 1993-08-12 | Idemitsu Kosan Co. Ltd | Powdered leather and method of producing the same |
-
1999
- 1999-04-27 DE DE1999119111 patent/DE19919111C2/en not_active Expired - Fee Related
-
2000
- 2000-04-26 WO PCT/EP2000/003759 patent/WO2000064982A1/en not_active Application Discontinuation
- 2000-04-26 CA CA002367926A patent/CA2367926A1/en not_active Abandoned
- 2000-04-26 EP EP00929431A patent/EP1177257A1/en not_active Withdrawn
- 2000-04-26 BR BR0010048A patent/BR0010048A/en not_active IP Right Cessation
- 2000-04-27 AR ARP000101984 patent/AR023611A1/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| EP1177257A1 (en) | 2002-02-06 |
| AR023611A1 (en) | 2002-09-04 |
| WO2000064982A1 (en) | 2000-11-02 |
| BR0010048A (en) | 2002-01-15 |
| DE19919111A1 (en) | 2000-11-02 |
| DE19919111C2 (en) | 2002-06-20 |
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