- 1 Types Of Polyamide Fibre
- 2 Properties Of Acid Dye
- 3 Classification Of Acid Dye
- 4 Metal Complex Dye
- 5 Washing Procedure (For Both Acid & Metal Complex Dye)
Nylon: It is a manufactured fiber in which the fibre-forming substance is a long-chain synthetic polyamide in which less than 85% of the amide (-CO-NH-) linkages are attached to two aromatic rings.
Types Of Polyamide Fibre
2 Types Of Fibres –
Nylon 6.6 and Nylon 6-dominate the polyamide fibre field. In recent years, however, a number of new polyamide fibres have assumed commercial importance depending upon polyamide fibre properties.
In some cases, these have already come into commercial production, in other cases, they are still under development, but show prospects of achieving real importance in due course. The commercial importance types of polyamide fibres are as follows:
- Nylon 6.6.
- Nylon 6.
- Nylon 6.10.
- Nylon 11.
- New types of polyamide fibres.
The most important polyamide fibre in terms of amount produced is nylon 6.6, that is, poly hexamethylene adipamide. The notation 6.6 denotes that there are 2 monomers, Each containing 6 carbon atoms which are required to form the polymer of this type of nylon. It is made by a condensation reaction between hexamethylenediamine and adipic acid.
Acid dyes are sodium salts of sulphonic acids but there are a few containing carboxyl groups. The acid dyes have a direct affinity towards protein fibres and polyamide fibres.
The acid dyes are so called because of the following reasons-
- The original numbers of the class (acid dye) are applied in a bath containing mineral or organic acid.
- They are all sodium salts of sulphonic and carboxylic acids and the anion is the active colored component.
Properties Of Acid Dye
- Water soluble.
- Always applied on acidic medium with organic or inorganic acid.
- Acid dyes have a direct affinity to polyamide fibres.
- Some acid dyes have good light fastness.
- Many bright shades are found.
- Most of the acid dyes are sodium salts of sulphonic acid and carboxylic acid and anion group is the active colored component.
Classification Of Acid Dye
On the basis of-
- Chemical structure.
- Dyeing characteristics.
- Dyestuff particles.
- Dyeing characteristics:
Acid dyes are commonly classified according to their dyeing behavior, especially in relation to the dyeing PH, their migration ability during dyeing and their washing fastness as follows;
- Level acid dyes.
- Fast acid dyes.
- Milling acid dyes.
- Super milling acid dyes.
Nylon fibre polymer may be represented as:
That is to say, Nylon polymer has an amino group at one end and carboxylic group in another. In the certain condition, it becomes-
Metal Complex Dye
Metal complex dyes are so called because of the metal, usual chromium, is already incorporates in the dye molecule during its manufacture. These dyes are also referred to as metal complex dyes.
The incorporation of the metal into the dye molecule has meant that the dye can be more readily applied to the fibre, thus eliminating part of the lengthy dyeing process.
There are two types of pre-metallized dyes: 1:1 premetallized dyes, which have one dye molecule for every metal atom and 2:1 premetallized dyes, colored which have two dye molecules for every metal atom.The fibres most colored with premetallized dyes are man-made synthetic nylon & natural protein fibres.
Dyeing With Pre-Metalised Dyes
1:1 Premetallized Dyes
The 1:1 premetallized dyes have to be applied in the very acid condition in order to achieve adequate exhaustion, therefore they have largely been replaced by the 2:1 premetallized dyes.
The very acid condition needed to apply these dyes can detrimentally affect the properties of the textile materials on which they are used. The 2:1 premetallized dyes are more easy to apply and require only slightly acid or neutral dye liquor. Therefore the 1:1 premetallized dyes are used only in exceptional circumstance.
2:1 Premetallized Dyes
The 2:1 premetallized dyes are applied from a slightly acid or neutral dye liquor. These dyes are soluble in an aqueous liquor because of the presence of the anionic solubilizing group in the dye molecule. The colored component of the dye is anionic and is attracted like acid dye to the positively charged amine groups of proteins and polyamide fibre.
The reaction between dye and nylon is given below:
Nylon-NH3 + Anionic metal dye Nylon-NH3-Dye
Properties Of Metal Complex Dyes
- No pre or post after treatment with metal salts is required
- Some of them are brighter than the chome dyes
- However their fastness is slightly lower than chrome dyes, but still, it is good enough
- Due to their ease of application and fastness properties, they are used for dyeing high-class dress material, hosiery, ladies wear
- Metal complex dyes that are otherwise known as pre‐metallizeddyes shows the great affinity towards protein fibres.
- Generally, it has been seen that metal complex dyes are Chromium or Cobalt complexes. Among the popular metal‐complex dyes, a variety is known as 1:2 metal‐complex dyes finds application for dyeing polyamide fibres.
- For dyeing wool, metal complex dyes are the most flavored. The following table shows a comparison between 1:1 metal‐complex and 1:2 metal complex dye.
- Metal complex dyes generally cannot be said as belonging to a particular application dye class.
- In fact, Metal complex dyes belong to numerous application classes of dyes. For example, they are found among direct, acid, and reactive dyes. When applied in the dyeing processes, metal‐complex dyes are used in pH conditions that are regulated by user class and the type of fiber type (wool, polyamide, etc). The pH levels for wool typically ranges from:
- Strongly acidic (ranging from 1.8 ‐4 for 1:1 metal‐complex dyes).
- Moderately acidic neutral (ranging from 4 ‐7 for 1:2 metal‐complex dyes).
Recipe Of Polyamide Fabric Based On Acid Dyes
In 50 degree temperature, we need to add dyes& auxiliaries than we need to follow the curve.
Functions Of Auxiliaries
UNIVADINE work as dye Leveling agent.
ALBEGAL work as crease preventive agent.
ALBATEX maintain the PH & it is the buffer of sodium acetate & acetic acid.
ALBAFLOW work as penetration accelerate.
Dyeing Recipe For 1:2 Metal Complex Dye
In 50 degree temperature, we need to add dyes & auxiliaries than we need to follow the curve.
Washing Procedure (For Both Acid & Metal Complex Dye)
- At 40 degree temperature we need to take fixing agent(1cc/l)+Softener(1cc/l)+Acetic acid(.5cc/l) at PH=4.5.
- Then we need to hot washed & cold washed the sample several times.