RETAINING MATERIALS
Mineral tanning agents
1. Chromium salt
2. Aluminum salt
3.Zirconium salt
4. Titanium salt
Vegetable tanning agents
Hydrolyzed
1.Mirobalan
2.Kestane
3.Valeks
4.Sumak
5. Oak bark
6-Dividivi
7-Tara
(some of it is
Condensed
1.Kebrako 2.Mimoz to
3.Mangrov to
4-Magrov
5- Gambir
synthetic tanning agents
1.Naftal the contents may
2.Fenolik are
3.Aldehit are
4.Reçineli are
5.Akrilik and
phenolic tanning
Tanning agents containing phenolic groups, without creating excessive thickness increase in the skin, and without accumulating in the glaze, plates by forming a soft attitude. Its binding to the skin is similar to vegetable tannins, but it does not contain as many phenolic groups. Molecular structures are not as big as vegetable tannins. Therefore, they become more stable and less oxidized.
The disadvantage is that they do not improve sweating fastness. They lighten the skin and allow it to be dyed to light colors. They can be used in the production of white leathers.
Resinous Tannins
Resinous retanning agents, on the other hand, are substances that fill the skin by filling between the fibers of the skin without reacting with the active groups of the skin.
Resinous tannins
• melamine,
• urea,
• dicyandiamide
They are obtained by condensing with formaldehyde (condensation). With the acidification of the environment and the increase in temperature, the molecular structures begin to grow and pile up between the skin fibers. Thus, an increase in thickness occurs on the skin and begins to fill the gaps of the skin.
While resin tannins create an increase in the thickness of the leather, it improves the sanding fastness of the leather and the dry closet fastness. Resinous tannins significantly lighten the color of the skin. Attention should be paid to dark color dyeing. If resin tannins are used more than 10%, the skins may harden in the press process. If used in an acidic environment, they accumulate on the skin of the skin.
Acrylic tannins
Aqueous solutions of acrylic acid, metaxylic acid, ethyl ester or methyl ester are used in skin retannage. These polymers penetrate the skin and improve the attitude and usage characteristics of the skin. 5 ph should be used in skin retannage. Filling effect increases if used with vegetable tannins. If acrylic tannins are given before other retanning agents, retanning agents are better distributed in the skin. Acrylic tannins tighten the skin of the skin, creating a firm skin.
• Acrylic tannins lighten the skin. Commercially, the most anionically charged ones are found. Anionic acrylic polymers improve the light fastness of leathers. They don't change the skin character too much.
Aldehyde tannins
In retanning process, aldehydes are mostly used to increase the sweat, wash and tear resistance of the skin. Glutardialdehyde, one of the aldehydes, is used in the retanning process. Glutardialdehyde should be used before neutralization when ph of skin is at 4.5 -5. If glutardialdehyde is given to the bath at high phs, the skin of the skin starts to shrink. They fill the glaze without roughening and allow the paint to be distributed homogeneously. If it is given in chrome tanning, it increases the consumption of chrome. Leathers retanned with glutardialdehyde should not be used in leather types to be dyed white when it turns yellow. As you use glutardialdehyde, the softness of the skin increases but the strength of the skin decreases.
Naphthalene syntans
• Dye penetration
• Dye leveling
• Distribution of vegetable tannins in the bathroom
using for.
The phs of these syntans are around 7.5-8.5.
Herbal Grains
They are included in retanning agents in herbal tannins. Vegetable tannins fill the skin too much and reduce the elasticity of the skin as they tighten the skin too much. Herbal tannins are fast and superficially attached to the skin. Therefore, accumulation on the surface is prevented by using naphthalene containing syntans. Neutralization process is done adequately and completely and the interest of vegetable tannins on the skin is reduced. Vegetable tannins increase the thickness of the skin. If it is used with acrylics, the desired increase in the fullness of the leather is achieved.
It increases sanding fastness. The presence of hydrophilic (water-loving) groups in the structure of vegetable tannins helps the shoe skins to sweat. They are offered as a commercial product alone or mixed with other synthetic tannins. The skin of the skins that have undergone excessive vegetation turns rough and the grains are formed on the skin. Vegetable tannins color the skin distinctly to their own colors, this should be taken into account in the retanning process.
Important vegetable tannins used in retanning
Mimosa: It is one of the most used vegetable tannins. They give tougher and fuller leathers than other herbs. They fill the glaze better without excessive puckering. They increase the sanding fastness of leathers. They reduce the elongation of the skins and reduce their strength. It is used in the retannage of soft character leathers. They make the color of the skin a little dull, and reduce the light fastness.
Sweet chestnut: Chestnut extracts give firmer and coarse skinned skin. Sanding fastness is better than mimosa. Causes low skin puffiness and shrinkage at low phs. They make the color of the leather matte. Light fastnesses are moderate.
Normal chestnut: The tanning power is high. It gives firmer and fuller leathers. They have a high tendency to shrink the skin. Since they tend to accumulate on the skin, they give rough skin and inelastic skin. They blur the color of the skin and make it matte. Light fastness is moderate. It has high water resistance. Should not be used alone if used in
retanning. Sulfite kebraco: They give less plump leathers. They give skin similar properties with mimosa. They give the skin a red color. The color gets darker as you wait. It should not be preferred in light color painting.
Tara: They give light colored and high light fastness leathers. It gives leather with soft tough and thin skin. Tara extracts are sensitive to iron ions. Tara extracts are used in combination with other grains. It is preferred in the production of leathers with screws that will be produced in pastel color and soft features.
1. Chromium salt
2. Aluminum salt
3.Zirconium salt
4. Titanium salt
Vegetable tanning agents
Hydrolyzed
1.Mirobalan
2.Kestane
3.Valeks
4.Sumak
5. Oak bark
6-Dividivi
7-Tara
(some of it is
Condensed
1.Kebrako 2.Mimoz to
3.Mangrov to
4-Magrov
5- Gambir
synthetic tanning agents
1.Naftal the contents may
2.Fenolik are
3.Aldehit are
4.Reçineli are
5.Akrilik and
phenolic tanning
Tanning agents containing phenolic groups, without creating excessive thickness increase in the skin, and without accumulating in the glaze, plates by forming a soft attitude. Its binding to the skin is similar to vegetable tannins, but it does not contain as many phenolic groups. Molecular structures are not as big as vegetable tannins. Therefore, they become more stable and less oxidized.
The disadvantage is that they do not improve sweating fastness. They lighten the skin and allow it to be dyed to light colors. They can be used in the production of white leathers.
Resinous Tannins
Resinous retanning agents, on the other hand, are substances that fill the skin by filling between the fibers of the skin without reacting with the active groups of the skin.
Resinous tannins
• melamine,
• urea,
• dicyandiamide
They are obtained by condensing with formaldehyde (condensation). With the acidification of the environment and the increase in temperature, the molecular structures begin to grow and pile up between the skin fibers. Thus, an increase in thickness occurs on the skin and begins to fill the gaps of the skin.
While resin tannins create an increase in the thickness of the leather, it improves the sanding fastness of the leather and the dry closet fastness. Resinous tannins significantly lighten the color of the skin. Attention should be paid to dark color dyeing. If resin tannins are used more than 10%, the skins may harden in the press process. If used in an acidic environment, they accumulate on the skin of the skin.
Acrylic tannins
Aqueous solutions of acrylic acid, metaxylic acid, ethyl ester or methyl ester are used in skin retannage. These polymers penetrate the skin and improve the attitude and usage characteristics of the skin. 5 ph should be used in skin retannage. Filling effect increases if used with vegetable tannins. If acrylic tannins are given before other retanning agents, retanning agents are better distributed in the skin. Acrylic tannins tighten the skin of the skin, creating a firm skin.
• Acrylic tannins lighten the skin. Commercially, the most anionically charged ones are found. Anionic acrylic polymers improve the light fastness of leathers. They don't change the skin character too much.
Aldehyde tannins
In retanning process, aldehydes are mostly used to increase the sweat, wash and tear resistance of the skin. Glutardialdehyde, one of the aldehydes, is used in the retanning process. Glutardialdehyde should be used before neutralization when ph of skin is at 4.5 -5. If glutardialdehyde is given to the bath at high phs, the skin of the skin starts to shrink. They fill the glaze without roughening and allow the paint to be distributed homogeneously. If it is given in chrome tanning, it increases the consumption of chrome. Leathers retanned with glutardialdehyde should not be used in leather types to be dyed white when it turns yellow. As you use glutardialdehyde, the softness of the skin increases but the strength of the skin decreases.
Naphthalene syntans
• Dye penetration
• Dye leveling
• Distribution of vegetable tannins in the bathroom
using for.
The phs of these syntans are around 7.5-8.5.
Herbal Grains
They are included in retanning agents in herbal tannins. Vegetable tannins fill the skin too much and reduce the elasticity of the skin as they tighten the skin too much. Herbal tannins are fast and superficially attached to the skin. Therefore, accumulation on the surface is prevented by using naphthalene containing syntans. Neutralization process is done adequately and completely and the interest of vegetable tannins on the skin is reduced. Vegetable tannins increase the thickness of the skin. If it is used with acrylics, the desired increase in the fullness of the leather is achieved.
It increases sanding fastness. The presence of hydrophilic (water-loving) groups in the structure of vegetable tannins helps the shoe skins to sweat. They are offered as a commercial product alone or mixed with other synthetic tannins. The skin of the skins that have undergone excessive vegetation turns rough and the grains are formed on the skin. Vegetable tannins color the skin distinctly to their own colors, this should be taken into account in the retanning process.
Important vegetable tannins used in retanning
Mimosa: It is one of the most used vegetable tannins. They give tougher and fuller leathers than other herbs. They fill the glaze better without excessive puckering. They increase the sanding fastness of leathers. They reduce the elongation of the skins and reduce their strength. It is used in the retannage of soft character leathers. They make the color of the skin a little dull, and reduce the light fastness.
Sweet chestnut: Chestnut extracts give firmer and coarse skinned skin. Sanding fastness is better than mimosa. Causes low skin puffiness and shrinkage at low phs. They make the color of the leather matte. Light fastnesses are moderate.
Normal chestnut: The tanning power is high. It gives firmer and fuller leathers. They have a high tendency to shrink the skin. Since they tend to accumulate on the skin, they give rough skin and inelastic skin. They blur the color of the skin and make it matte. Light fastness is moderate. It has high water resistance. Should not be used alone if used in
retanning. Sulfite kebraco: They give less plump leathers. They give skin similar properties with mimosa. They give the skin a red color. The color gets darker as you wait. It should not be preferred in light color painting.
Tara: They give light colored and high light fastness leathers. It gives leather with soft tough and thin skin. Tara extracts are sensitive to iron ions. Tara extracts are used in combination with other grains. It is preferred in the production of leathers with screws that will be produced in pastel color and soft features.
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