Studies on The Effect of Various Kind of Protin Binder to Produce High Quality Glaze Kid Leather

Glaze kid leather is a light fine high-class shoe upper leather. Principle of glaze kid leather is designed depending its. Like, full in substance, tine, smooth, lightly, glossy soft to feel, resilient, and non-stretchy etc, and also from, its physical quality requirements. On the whole its principle can be summarized in the following way.

Goat skin has length 70-90 cm without any defect and disease may be chosen for glaze kid leather. Soaking is done in as usual manner, prolonged soaking is avoided as far as possible, because it may loose hide substance though, and bacteria attack.

Liming is sharp and not very prolonged. Unhairing by painting is usually done because it keeps the goat hair unaffected, which is an important by product of glaze kid leather. After painting pelts are also impedes in flesh lime liquor with certain quality of sharpening agent. After liming, sharp declining and bedding is done. After deliming and bating pelts should be flaccid, silky grain, clean and should lie in any position in which it is kept.

Cr – attaining can be done following both single and double bath process, but best known process according to the practice of Dr.belaveky’s is the skins are treated with chrome alum and dichromate in the same bath to which, after some time, hypo and acid are added. Liquor of anning should not mask.

Neutralization should done with mild alkalis and pH should be near scout 4.8. it will be better if we can avoid neutralizing syntax. Retaining is carried out in a way that there in no surface deposition.

Direct dyes have been found to have good affinity for chrome leather, acid dyes are also need. Basic dye is used to increase brilliancy in the toping. It must note contain any kind fat or oils to its surface and fat contain should not exceed 6-8%. Mainly used synthetic and semi-synthetic fat because sulphited fats are highly penetrative and make leather too soft and natural bats have very poor fixing power. So may come out on pressure. Finishing is very vital in glaze kid leather. It is essential to use smallest possible quality of pigment finish to preserve the natural grain of goatskins and to impart smooth and soft feel. It should be resistant to dry and wet rubbing and also key test should not break the finish film until the it is cracked by key test, in season coats, now-a days caseins based water pigment finishes employed, smooth grain. Top coat, protein binders, poly amide etc, used. Fixing is done by HCHO.

Protein binder has very good effect upon glaze kid leather. It can cover most of the type of defect of the grain. Protein are insoluble in water but soluble in organic solvent and are opaque. Protein has very low binding effect. So it need to mix with wax emulsion and polyurethane impart good gloss on the leather. But if there were some resin it will destroy the protein binder capacity. After completing various type of testing it is found the finished glace kid leather has made in fine quality and in Bangladesh we can make glace kid leather which will not be expensive for us and it will not take more money to produce high quality glazed kid leather as export quality.

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Studies on The Production of Crackle Finished Leather

The Art of Crackle Finish Leather

Crackle finish is an interesting finish that gives the appearance of age on the surface of painted pieces. This finish uses a commercial product and requires two colors of paint – one for the undertones and the other for the top.

A crackle finish, method of forming a crackle finish and a kit for forming a crackle finish. The crackle finish includes a base coat of latex paint or stain on a surface to be treated. A crackle coating is applied over the base coat and dried to tack dry or completely dried. A latex wood filler is applied over the crackle medium. As the latex wood filler dries, it forms islands or domains separated by cracks or valleys revealing glimpses of the underlying base coat.

A crackle glaze or varnish is a finish which creates a crackled effect. Many people use crackle glazes for antiquing, because peeling, crackled paint has an old-fashioned look which goes especially well with restored furniture. Crackle glazes can be used on a wide range of things including pottery, furniture, picture frames, and even walls. A number of craft stores sell materials for crackle glazing, and you can also accomplish the effect with a few supplies you probably already have around the house.

Crackle Finish- The Basic Techniques:

When a crackle finish is made, one color is laid down as a base coat and allowed to dry before a crackling medium is painted over it. Once this medium dries, another coat of color is applied, and cracks and peels start to appear almost immediately. To seal a crackle glaze, a clear varnish or polyurethane sealer can be used. This sealer also halts the crackling process so that the second layer of color doesn't flake off entirely.

The crackle glaze effect is sometimes called craqueleure, and in fine art, it is sometimes used as a tool to date artworks and establish their provenance. Forgers spend lifetimes mastering the art of a properly crackled final layer of paint in the hopes that their works will pass muster by art inspectors; a dedicated forger may infuse a craqueleure with dust and particulates from an old piece of art from the right region in case an art inspector decides to chemically analyze the finish.

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Studies on The Production of Football Leather from Cow Hide

Football Leather - All You Need to Know

Modern worldwide leather market is now a days very fond of football leather. Finished leather is also an intermediate product. Which serves as a raw material for finished leather is therefore, fashion driven, requiring more responsiveness to the market, whereas crust leather is more a commodity type product. Since 1990-91, Bangladesh have started exporting footwear and other leather goods. Bangladesh currently export leather footwear to Europe and Japan.

Leathers used for footballs are mainly chrome tanned leathers that have not been retanned or only lightly retanned in thickness of 2.5 – 3.0 mm. But generally ‘Football leather’ is not used for footballs  exclusively as it’s name might imply, but it is used for making the outer coverings for the football, the volleyball, the water polo ball, the rugby ball and many other balls of a similar nature.

Characteristic Properties of Football Leather :

1. Football leather must have high degree of resistance to the penetration of water. (great extent of water repellency)
2. It should have high tensile strength.
3. It should have high stitch tear strength.
4. It should be non-stretchy.
5. It should be non-elastic.
6. It should have good abrasive resistance.
7. It should have perfect fastness properties.
8. Its fibre structure should have low angle of weave.
9. The void space of the leather should be reduced filling with hard materials and its capillary action should be minimum.
10. It should have tightness and its elongation must not be more than 4%.
11. It should be thick (i.e. 2.1 mm-2.3 mm)
12. It should be resistant on inert in acid alkaline medium.

Principles of Football Leather Production

The Thick butt portion of cow hides are taken for making football leather. To get various desirable physical properties special care should be taken from soaking to finishing during manufacture.

Proper soaking is done with preservative. Liming is accomplished in such a way that less interfibrillary substances are removed. (i.e. Sharp liming). For high strength properties excessive swelling and splitting of the pelt should be avoided. Delimiting is done just after fleshing and without batting it is pickled.

For high strength and low stretchiness, it is tanned with high percentage of unmasked chrome and properly rechroming is done with chrome syntan to get more fullness. It is neutralized with Sodium (Na) or Potassium (K)-salts of organic acid for non-stretchiness and inertness.

Water-proofing fat liquor is used in fatliquoring with raw oil of high viscosity. After fat liquoring, chrome caping operation will be done with self basifying chrome. It is dyed with full penetrative dye. Then it is finally dried under maximum stretched condition in all direction. In finishing surface of football leather should be coated with water proofing agent in a thin finish film.

As production capacity in finished leather and leather goods is developed in Bangladesh, new jobs will be acquired, and markets will be accessed. In standard quality specification, thickness of football leather is min. 2mm. The Europe, Australian and Indian cow hides are generally thick. So, it is easier to keep the thickness 2mm. But in our country’s cow hide quality is not good for many reasons.

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Studies on The Manufacturing Procedure of Book Binding Leather

The decayed leather binding with a flaking or powdery surface and a broken spine is an all too common sight in many book collections. Bindings in this condition will remain a perpetual and ever increasing problem unless binders ensure the leather they use has a long term resistance to acidic atmospheric pollutants. Binders tend to select leather on aesthetic appearance and the way the leather handles during the binding operations. Insufficient consideration is given to the durability of the leather, but unfortunately there is little to guide the purchaser with regard to this property.

However the last eight years have seen the development of a combination tannage involving both vegetable tannins and aluminum salts that confers on the binding leather a markedly increased resistance to atmospheric pollutants. Such archival quality leathers with this semi-aluminum tannage are now being produced commercially and this paper describes the rigorous testing to which such leathers have been subjected in order to demonstrate their superior durability.

Book-binding leather are more softy usually full vegetable tanned leathers made from goat, sheep and calf skins. Book-binding leather should be-

• Book-binding leather must have very good tensile strength.
• Book-binding leather must have resistance to perspiration fastness.
• The grain finished leathers should be well let out to give a smooth grain surface.
• The grain-break should be free from looseness and pipyness.
• Book-binding have water -proof.
• Book-binding have by lasting 100-150 years.
• Book-binding leather have good tearing strength.
• Aesthetic feel.
• Used dye should not be pH sensitive.
• Light fastness not less than rating 4 on the blue wool scale.
• The fat content should not be less than 4% of the leather weight.

We are living new millenniums. Technology is growing rich every day. People demand is increasing. Many competitors are waiting in market to fulfill their demands. If we want to survive in this competition we have to acquire modern technology. Technology never now without successful experiment.

It is a fact that we are accustomed to use leather goods in our life to a large extent. Further more using leather goods are also a matter of status and prestige in many countries. As observed, it is easy to make book binding with leather but difficult to maintain it’s quality. For this reason, I took low graded goat skin and turned it to quality book binding leather. All the way of my project work I always give a though of quality and production cost.

Foreign currency can be gained in a significant way which may develop the country economy as raw materials and labor are two most important factor but available in our country.

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Studies on The Effects of Enzyme in Leather Processing

The use of enzymes in leather processing has a long and colorful history and a brief outline of this fascinating subject may perhaps help to put our present preoccupations into some perspective. Enzyme dependent processes have been employed in leather making for thousands of years. The enzymatic degradation of individual components of skins such as derma tin soleplate proteoglycan or elastin that can occur during bating process to achieve specific production objects, for example, the development of rapid unhairing liming processes or the production of more open or relaxed fiber structure.

The enzymatic formulations used in the beam house are [1] soaking sides for salted and dry raw hides and preserved fur skin [2] unhairing formulations for all types of hides and skins.[3]alkaline bates for scud removal and opening up of fiber structure [4]acid bates for blue chrome and fur skins [5] enzymatic degreasing agents for greasy skins and [6] enzymatic formulations for by production utilization.

Tanning is a process of converting participle outer covering of animals to no participle leathers with definite physical, chemical and biological properties so that they can be used in our daily life and industries. Before going into details, if necessary to discuss a little bit about the composition of hides and skins.

Reasons for using enzyme

1. Improve the quality.
2. Get a better yield.
3. Environment friendly.

Among these, protein is the only most important material for leather making 64 percent to 94 percent of the solid matters of the hides and skins are tot fibrous proteins known as albumin and musing are found in hides and skins. During soaking liming, bating, most of soluble proteins and fibrous proteins like keratin, reticular etc are removed. Then the white collagen fibers are tanned to usable leather.

Most of the enzymes used in the tannery processing are still of the proteolysis type, required to selectively degrade the peptide bonds of the different non collagen us proteins of hides and skins whilst avoiding any damage to the collagen itself.

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Application of Organometallic Compounds in Leather Processing

History of Organometallic Compounds

Early developments in organometallic chemistry include Louis Claude Cadet synthesis of methyl arsenic compounds related to cacodyl, William Christopher Zeise's platinum-ethylene complex, Edward Frankland discovery of dimethyl zinc, Ludwig Mond discovery of Ni(CO)4, and Victor Grignard organomagnesium compounds. The abundant and diverse products from coal and petroleum led to Ziegler-Natta, Fischer-Tropsch, hydroformylation catalysis which employ CO, H2, and alkenes as feedstocks and ligands.

Recognition of organometallic chemistry as a distinct subfield culminated in the Nobel Prizes to Ernst Fischer and Geoffrey Wilkinson for work on metallocenes. In 2005, Yves Chauvin, Robert H. Grubbs and Richard R. Schrock shared the Nobel Prize for metal-catalyzed olefin metathesis.

Organometallic Compounds

Organometallic compounds are also known as organo-inorganics, metallo-organics and metalorganics. Organometallic compounds are distinguished by the prefix "organo-" e.g. organopalladium compounds. Examples of such organometallic compounds include all Gilman and Grignard reagents which contain lithium and copper, and magnesium respectively. Tetracarbonyl nickel, and ferrocene are examples of organometallic compounds containing transition metals.

In addition to the traditional metals and semimetals, elements

such as boron, silicon, arsenic, and selenium are considered to form organometallic compounds. Examples include organomagnesium compounds such as iodo(methyl)magnesium MeMgI, diethylmagnesium (Et2Mg); organolithium compounds such as butyllithium (BuLi), organozinc compounds such as chloro(ethoxycarbonylmethyl)zinc (ClZnCH2C(=O)OEt); organocopper compounds such as lithium dimethylcuprate (Li+[CuMe2]); and organoborane compounds such as triethylborane (Et3B).

Many organometallic compounds exist in biological systems. For example, hemoglobin and myoglobin contain an iron center bonded to a porphyrin ring; magnesium is the center of a chlorin ring in chlorophyll. The specialized field of such inorganic compounds is known as bioinorganic chemistry.

Bangladesh has been a source of raw materials, ranging from hides and skins at the beginning of mostly crust and some finished leather. Since 1990-91, Bangladesh has started exporting footwear and other leather goods. Export earning from leather goods, were negligible from 1972-73 through 1989-90 averaging only Tk. 0.114 million per annum. But it has increased considerably since 1990-91 and has reached around TK. 700 million in 1993-94. It is significant that the demand of shoe upper leather is increasing in the international Market.

Keeping in mind both the points the international demand and availability of raw hides and skins. I have intended to develop a recipe for the production of shoe upper leather. Moreover, Production capacity in finished leather and leather goods is developed in Bangladesh, new jobs will be acquired, and markets will be accessed.

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Production of Sued Leather from Wet Salted Goat Skin

A term taken from the French, "gants de Suède" (Swedish gloves), and applied to a leather finished on the flesh side by buffering so as to raise a velvet-like nap. The typical suede leather is produced from the smaller skins, such as calfskin, kidskin, lambskin and goatskin, although cowhide has also been used.

The nap is produced by buffing or wheeling the surface on the flesh side, or the split side of flesh splits; velvet suedes, however, are buffed on the grain side. A common criterion of good suede leather is that the fibers of the nap should be of uniform length and tightly packed together, in order to give a resilience to the nap so that it does not readily shown fingermarks. c The firmness of the nap depends upon the density and compactness of the fiber structure. Velvet suedes are finer than flesh suedes and a younger animal, such as a SLUNK , produces an even finer suede.

A principal concern in making suede leather is to retain the fine nap and still produce a soft leather; however, the leather must not be made soft by means of improper FAT-LIQUORING, because even a small excess of oil will produce a greasy suede nap.

Suede leather, often tooled in blind, was used in England as early as the 17th century, and in the 18th and early 19th centuries in blank book binding.

Two distinct layers will be seen-

1. Thin upper velvety layer, and
2. Thick lower compact layer.

The thin grain layer, compact but highly splitted and practically free from interfibrillary materials is like the flesh layer. The reticular sheaths around the collagen fiber bundles are completely ruptured and the fibers are separated from each other in the upper layer while in the middle portion the reticular sheaths remain intact even though sufficient degree of splitting inside the fiber bundles are maintained.

BRIEF DISCUSSION ABOUT SUEDE UPPER LEATHER PRODUCTION

Suede shoe upper leather is one of the most fashionable items in the world market. The suede shoe upper is mainly used in cold countries where the leather has to perform the role of shoe upper and garment together. In suede leather no looseness is desire and on the other hand it has to be soft in nature. So the control is very important from beam house to finishing.

The review on production of suede upper leather indicates that it requires a good understanding of science and technology of leather making, constant vigil and care during processing and abundant common sense in suitability monitoring the fee stock and the process.

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Bag Leather from Lower Grade Cow Hide

Leathers which are used for the manufacturing of different types of bag are known as bag leather. Mostly these are chrome or vegetable tanned from lower grade raw stock having thickness 1.0-1.5 mm (or above for some particular article).

Combination tanning is carried out with a combination of chrome, vegetable, synthetic or other tanning agents to improve the fullness and firmness and some other desire properties of shoe upper. The main combinations are semi-chrome and chrome-retanned leather. Leather is first tanned with vegetable and then retanned with chrome tanning agent is semi chrome retanned leather. Chrome retanned leather is softer and flexible and mostly used as shoe uppers.

PROPERTIES OF BAG LEATHER

1. The physical appearance of finished leather should look attractive with clear grain.


2. The leather must possess a soft and mellow ‘handle’ with fine and tight ‘break’ on the grain. The must be stable against repeated tensile and compressive strains and bending.


3. The leather must possess high strength properties i.e. tensile strength, stitch tear strength, split tear strength, elongation at break etc.


4. The leather must possess the hygienic property of being permeable to water vapor and air.


5. The finish on the leather should have high adhesion and must be durable against wet and dry rubbing.


6. Should be highly color fast.


7. Should have dry and wet rub fastness.

THE MAIN REQUIREMENTS OF IDEAL BAG LEATHER:

AESTHETIC APPEAL

The leather should have elegant attractive appearance. Elegant appearance requires that the grain surface must be distinguishable from that of a leather substitute and colors, gloss and grain appearance should be attractive and appeal to the buyers of the bag. The leather should retain the colour, should not stain wearer's clothes and should have ability to take polish. Not only looks but also the feel of the leather by touch in the bag are important.

PHYSICAL PROPERTIES

The most important requirements for bag leather are good adhesion (wet and dry) rub fastness and high temperature performance during plating, hot air drying and lasting. Strength and stretch of upper materials used in shoe making are good guides for their suitability. Low strength and stretch of upper leather and consider unsuitable for use as shoe uppers.

The important physical properties of upper leather which determine its suitability use in shoe making are:

1. Tensile strength


2. Stitch tear strength


3. Split tear strength


4. Elongation at break


5. Distension at grain crack

Modern worldwide leather market is now a days very fond of bag leather. Finished leather is also an intermediate product. Which serves as a raw material for finished leather is therefore, fashion driven, requiring more responsiveness to the market, whereas crust leather is more a commodity type product. Bangladesh currently exports leather bags to Europe and Japan.

As production capacity in finished leather and leather goods is developed in Bangladesh, new jobs will be acquired, and markets will be accessed. But in our country’s cow hide quality is not good for many reasons, but the lower grade raw stock can be upgraded to a higher level by using different tanning and finishing techniques.

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