JP2001354895A - Treatment of leather - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating a leather product such as leather footgear by which water-repellency and/or oil-repellency can be imparted to the leather product without providing damage, and simultaneously mild to the environment, and further to provide a composition for treating the leather. SOLUTION: The use of a water-based air-curable composition for treatment of the leather for imparting the water-repellency and/or oil-repellency thereto is characterized in that the composition comprises water and a cationic perfluoroalkyl acrylate copolymer having a glass transition temperature (Tg) up to 40 deg.C. The composition for treating the leather comprises the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a treatment for imparting water repellency and / or oil repellency to leather products. More specifically, the present invention does not damage leather footwear,
At the same time it concerns the processing of environmentally friendly leather footwear.

[0002]

BACKGROUND OF THE INVENTION The treatment of fabrics, shoes, carpets, and various other textile products to impart water and / or oil repellency, and thereby impart stain resistance, is well known. Very often initial processing is performed during the manufacture of the product, and subsequent processing is required to restore the water and / or oil repellent finish lost from use.

[0003] In order to impart water repellency and / or oil repellency, various treatment compositions containing a fluorine-based chemical have been used. Traditionally, such compositions have been water-based (aqueous), and when applied, to bind the fluorine-based chemicals to the product to be treated and to evaporate the water, Heat is used. However, this is far from ideal for the processing of products made from leather, especially footwear. Because when you apply heat,
Leather dries out and can tear.

One example of this type of aqueous treatment composition is disclosed in US Pat. No. 5,902,637. This document discloses a method for restoring water repellency or oil repellency to cloth, footwear, and woven fabric which have been previously subjected to a water repellent or oil repellent finish. In this method, a product to be treated is washed, and then a composition containing a fluoroacrylate copolymer is sprayed while the product is in a wet state. Thereafter, the product is dried at a temperature of 55-75 ° C. (130-170 ° F.) to crosslink the fluoroacrylate copolymer with the pre-existing water or oil repellent coating on the product and to form a uniform Coating. The use of this type of composition is not suitable for processing leather goods.

[0005] Treatment compositions that do not require the use of heat typically have an organic solvent because they have a lower boiling point than water and are relatively easy to evaporate. However, a general trend throughout the industry is to produce environmentally friendly products, and the use of compositions containing organic solvents, even in small amounts, is undesirable.

US Pat. No. 5,370,919 discloses a composition for treating textile products, which comprises a water-soluble or water-dispersible fluorine-containing polyoxyalkylene compound, a solid. It consists of a water-soluble or water-dispersible antifouling agent and water, and optionally up to 60% by weight of a water-miscible organic solvent. Although the organic solvent is said to be merely optional, the only composition illustrated comprises a mixture of water and an organic solvent, specifically ethylene glycol. Moreover, while the composition is stated to be generally applicable to textile products, including leather, the only test results reported are for textile products.

US Pat. No. 4,668,726 discloses compositions based on various fibrous materials, especially other fluorochemicals, to impart water and oil repellency to carpets. The composition consists of a complex mixture of various fluorochemicals in the form of an aqueous emulsion or an organic solution. More specifically, the composition comprises a cationic fluorochemical and a non-ionic fluorochemical, optionally a fluorine-containing polyoxyalkylene and / or
Alternatively, it is composed of a hydrocarbon-based nonionic surfactant.

[0008] US Patent No. 4,681,790 also discloses other compositions based on fluorochemicals for imparting water and oil repellency to fibrous materials. The composition comprises:
It consists of what has been reported as a synergistic mixture of an aromatic fluorochemical and a fluoroaliphatic polyoxyalkylene in a liquid medium containing water as the main component and a small amount of a water-miscible organic solvent.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a leather treatment method which can be cured without heating and can impart excellent water repellency and / or oil repellency to leather products. is there. More specifically, an object of the present invention is to provide a use of a composition containing a fluorine-based chemical substance capable of treating such leather in leather treatment, and to provide a composition for treating leather.

[0010] The relatively simple composition of water and a cationic perfluoroalkyl acrylate copolymer having a glass transition temperature of up to 40 ° C. is now surprisingly effective on leather goods, especially leather footwear. It has been found that these compounds provide a good water repellency and / or oil repellency. The relatively low glass transition temperature of the fluoroacrylate copolymer used allows the composition to air cure (ie, cure without heating), thereby preventing damage to the leather being treated. . Furthermore, the absence of any substantial amount of organic solvents makes the composition environmentally friendly.

[0011]

Thus, according to the present invention, in the use of a water-based air-curable composition for leather treatment for imparting water repellency and / or oil repellency, the composition comprises water and water. A cationic perfluoroalkyl acrylate copolymer having a glass transition temperature (Tg) of up to 40 ° C. is provided.

Further, according to the present invention, there is provided leather footwear treated with the aqueous air-curable composition.

Further, according to the present invention, a water-repellent and / or water-repellent composition comprising a water-based air-curable composition containing water and a cationic perfluoroalkyl acrylate copolymer having a glass transition temperature (Tg) of up to 40 ° C. A leather treatment composition for imparting oil repellency is provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the present specification, an aqueous air-curable composition (composition for treating leather) is composed of water and the above-mentioned cationic perfluoroalkyl acrylate copolymer (hereinafter simply referred to as “fluoro acrylate copolymer”). And preferably also consist essentially of these, which, in conjunction with air curing, are essential for achieving the desired water and / or oil repellency. It means that it is the only ingredient. More specifically, the composition does not require any other water repellent and / or oil repellent components, and more preferably, the invention provides that such other components have significant water repellency. And / or the presence in an amount that provides an oleophobic effect is excluded.

[0015] However, the composition may be used conventionally in the treatment of leather or may contain additional component materials that assist in applying the composition to leather. For example,
When the composition is to be applied as a spray, the composition can include any type of propellant that is conventionally used in the art. Preferred embodiments include butane, propane, and carbon dioxide gas, but may be simply compressed air.

However, most preferably, other than the propellant gas, if desired, the composition does not include other additional components (ie, components that are not present therein when the copolymer is provided). .

The fluoroacrylate copolymer is at about 40 ° C.
Having the following glass transition temperature (Tg) is important for the present invention. Preferred fluoroacrylate copolymers have a Tg value of about 30 ° C. or less, for example up to 25 ° C., with the most preferred Tg range being 15-22 ° C. If desired, a mixture of fluoroacrylate copolymers can be used.

The fluoroacrylate copolymer preferably used in the present invention is usually formed by copolymerization of a fluorine-containing acrylate monomer and a fluorine-free polyoxyalkylene monomer. Oxyalkylene monomers may also be used. Preferably, the fluoroacrylate copolymer is
It is prepared by reacting at least one fluorine-containing monomer or oligomer that can be prepared by telomerization with another monomer or oligomer. Such preferred copolymers are, for example,
Eliminate copolymers prepared from perfluoroalkylsulfonate oligomers that produce harmful by-products.

The fluoroacrylate copolymer may be linear, but is preferably branched because the branched polymer structure has been found to improve film forming properties at low temperatures. Particularly preferred is a branched copolymer having an active curing point at a branch position. Further, an aliphatic copolymer is preferable to an aromatic copolymer.

A particularly preferred example of a commercially available fluoroacrylate copolymer preferably used in the present invention is a Nuba ACFP liquid supplied by Clariant (Nuva ACFP L).
liquid) and Nuva ACFPM liquid (Nuba ACF)
PM Liquid) (trade name). Other fluoroacrylate copolymers of the same general type as these materials are particularly suitable for use in the present invention. Nuba ACFP
The liquor and Nuba ACFPM liquor are supplied as aqueous fluoroacrylate copolymer emulsions and contain a mixture of different fluoroacrylate copolymers. Generally, they contain a fluoroacrylate copolymer at a solids content of about 20% by weight and may be used as supplied or may be further diluted according to the type of finish required for the leather to be treated. Is also good. However, higher polymer contents can be used.

The Nuba ACFP liquid contains very small amounts of acetone, for example up to 1% by weight. Such small amounts, or slightly higher amounts, of organic solvents are acceptable because they have a minimal impact on the environment, especially once they are further diluted with water. Nuba ACFPM fluid is a solventless version of Nuba ACFP fluid, and therefore contains the same polymer species as Nuba ACFP fluid. Both materials usually contain an emulsifier to help disperse the fluoroacrylate copolymer in water. Typical amounts of emulsifier are up to 7% by weight, but slightly higher amounts, for example up to 10% by weight, are acceptable.

The fluoroacrylate copolymer is generally used in an amount of 0.5 to 20% by weight, preferably 1 to 20% by weight, depending on the application method (coating method) and the required level of water repellency and / or oil repellency.
It is contained in the composition for leather treatment in an amount of up to 15% by weight, more preferably 2 to 10% by weight, most preferably 2 to 6% by weight.

[0023] No additional organic solvent is resolutely added to the leather treatment composition. Furthermore, it is preferred that any organic solvent is less than 1% by weight, more preferably less than 0.5% by weight, based on the total weight of the leather treatment composition.

The leather treating composition of the present invention can be used to protect various leathers including suede and nubuck. Further, the composition can be used for protection of various leather products, but is preferably used for protection of leather footwear such as shoes, boots and sandals.

[0025] The composition is applied to the leather to be treated by spraying or coating. As mentioned above, when the composition is applied by spray,
A propellant gas may be included. Preferably, however, no propellant gas is used for environmental reasons, and the composition is applied by means of a pump spray device. After treatment, the leather is left to dry at ambient temperature, usually up to about 25 ° C. Drying may be performed for up to 24 hours, but typically takes about 12-16 hours, or is completed within 12 hours.

Drying and concomitant crosslinking of the fluoroacrylate copolymer form a substantially continuous coating on the leather, which provides good water and / or oil repellency properties. .

The composition can be used to provide an initial protective coating on leather and / or can be used to restore a protective coating damaged by wearing.

[0028]

The invention will now be further described by way of the following examples. The following test was used to evaluate the water repellency properties of the treatment composition according to the present invention.

(1) Various isopropanol (IPA) using a water repellency test pipette
/ Water mixture is dropped on the test material. After 30 seconds, each drop is removed from the test material using a tissue. The water repellency is the highest I that does not leave traces or wet the test material.
It corresponds to a mixture with a PA content. The water repellency values (grades) and the corresponding IPA / water mixtures are shown in Table 1 below.

[0030]

[Table 1]

(2) Oil Repellency Test This test is used to determine the oil repellency of textiles and is performed according to the industry standard test AATCC118. The various standard test solutions shown in Table 2 below are dropped on the test material using a pipette. After 30 seconds, each drop is removed from the test material. The oil repellency corresponds to the highest numbered test liquid that does not leave or wet the test material. The oil repellency (grade) corresponding to the standard test liquid is shown in Table 2 below.

[0032]

[Table 2]

(3) Sprayability test This test has been used to determine the water repellency of textiles against surface wetting by water and has been approved by the world standard B.
S EN 24920 1922, ISO 4920 A
Implemented according to ATCC 22. Specific volume (250
(ml) of distilled water on the test material. The test material is
Mounted on a ring and inclined 45 ° to vertical so that the center of the test material is 150-152 mm below the spray nozzle. Immediately after the end of spraying, remove the holder together with the test material and tap twice. The appearance of the test material is then compared to the description taken from the AATCC Spray Test Ratings Table and to both standards in the figure to determine the degree of spraying. Table 3 below shows the spray degrees (grades).

[0034]

[Table 3]

Example 1 5% by weight of Nuba ACFP liquid
For test materials pretreated with 10% and 15% by weight aqueous solution (corresponding approximately to 1%, 2% and 3% by weight of effective polymer) and air-cured for 24 hours,
As shown in Table 4 below, a water repellency and / or oil repellency test was performed.

[0036]

[Table 4]

The results reported in Table 4 show that while the water and oil repellency for carpet samples is consistently low, the water repellency for leather samples is comparable to synthetic fibers such as polyester and nylon. Is shown. further,
The oil repellency for leather is lower than that of synthetic fibers, but is clearly improved, and is significantly improved for carpet samples.

According to further studies on the water and oil repellency properties of the compositions of the present invention, for most of the leather and nubuck leather samples tested, the compositions were applied by the Applicant to footwear. Proofer Pro
superior) compared to commercially available solvent-based fluorochemical footwear protectors sold as. In addition, the compositions of the present invention exhibit consistently superior water and oil repellency properties compared to various other commercially available wax-based and silicone-based footwear protectants.

[Example 2] A spray degree test was performed on leather and polyester having different degrees of surface roughness. Each sample was pre-treated with a 20% by weight aqueous solution of Nuba ACFP solution (approximately 4% by weight polymer) before testing and cured for 24 hours.

The results achieved are shown in FIG. In FIG. 1, test materials 1 and 4 are different nubuck leathers, test materials 2 and 3 are different smooth leathers, and test material 5 is polyester.

The results show that the treatment composition imparts a much better sprayability, ie water repellency, on leather than on polyester under test. I have. This is somewhat surprising, keeping in mind that the results of the water repellency test show that the low concentration of Nuba ACFP liquid shows essentially similar results for various leathers and various synthetics. It should be.

[0042]

According to the present invention, it is possible to impart water repellency and / or oil repellency to a leather product such as leather footwear without damaging the same, and at the same time, to provide an environmentally friendly treatment method and leather treatment. A composition is provided.

[Brief description of the drawings]

FIG. 1 is a graph showing the results of a spray test on various leathers and polyesters.

[Explanation of symbols]

 1: Nubuck leather 2: Smooth leather 3: Smooth leather 4: Nubuck leather 5: Polyester

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Carolina Jones Dee 55, UK 4 Cutie Derbyshire, Alfreton, Clover Knock Industrial Park, Grange Closed, F-term in Grangers International Limited 4F056 AA01 BB02 CC12 CC65 DD04 DD44 EE20 FF16 FF19 4H020 BA13 4J038 CG141 CH251 GA12 HA15 MA08 MA13 NA07 PA06 PB02 PC09

Claims (10)

[Claims] 1. Use of a water-based air-curable composition for leather treatment for imparting water repellency and / or oil repellency,
The composition has a glass transition temperature (Tg) of up to 40 ° C. with water.
Use of a water-based air-curable composition comprising a cationic perfluoroalkyl acrylate copolymer having the following formula: 2. Use according to claim 1, wherein the composition consists essentially of water and the copolymer. 3. The use according to claim 1, wherein the copolymer has a Tg of up to 25 ° C. 4. The use according to claim 1, wherein said copolymer is a branched copolymer. 5. The use according to claim 1, wherein the composition contains 0.5 to 30% by weight of the copolymer. 6. The method according to claim 1, which is for treating leather footwear.
Use according to any one of the preceding claims. 7. The use according to claim 1, wherein the composition is applied to leather goods by spraying. 8. Use according to any one of the preceding claims, wherein the composition is applied to leather goods by means of a coating. 9. Leather footwear treated with the composition according to any one of claims 1 to 5. 10. Glass transition temperature (T) up to 40 ° C. with water
a water-based air-curable composition comprising a cationic perfluoroalkyl acrylate copolymer having g) and a water-repellent and / or oil-repellent composition for imparting water repellency and / or oil repellency.