JPS5822583B2 - Dyeing method using microwave heating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for dyeing various textile products by microwave heating.

Conventionally, as a dyeing method using high-frequency heating, a method is known in which textile products are impregnated with a certain amount of dyeing liquid and heated with microwaves (Japanese Patent Laid-Open No. 48-46669, Japanese Patent Publication No. 5
2-28141).

When polyester fibers and blends with other fibers are continuously dyed using this method, the disperse dye is dispersed in an aliphatic polyhydric alcohol with a boiling point higher than that of water and a fairly high dielectric constant. Immerse the object to be dyed in the dye solution, squeeze it with a mangle to 100% pick-up, and heat it in the microwave.

However, heating a substance by microwaves generates heat by absorbing electromagnetic energy within the electric field, so the heating efficiency of the heated object is governed by the voltage and the electromagnetic wave absorption ability of the substance, such as textile materials, dyes, and solvents present in the electric field. In actual microwave heating, temperature control is difficult because various factors such as electromagnetic wave absorption ability, change in dielectric constant due to temperature rise of solvent and water, and thermal properties (heat radiation constant and heat storage effect) due to the structure of the fiber material interact with each other. It was extremely difficult.

In addition, a solvent with a high dielectric constant is used to enhance the heating effect, but microwave heating accelerates the evaporation rate of the solvent contained in the fibers, causing a rapid temperature rise and reducing the amount of solvent in the fiber matrix. There are problems such as a change in the evaporation partial pressure, which causes a bumping phenomenon, and the fact that the heat of evaporation is taken away from the fiber matrix, which lowers the temperature of the fiber matrix and causes uneven dyeing.

Furthermore, in the dyeing of fibers, there is a distribution-limiting rate between the dye and the fiber matrix, which is governed by a certain diffusion ability, and with rapid heating such as microwave heating, the evaporation rate of the solvent is fast, so the dye is absorbed inside the fiber. Another drawback was that it did not diffuse well into the dye, making it impossible to achieve sufficient staining.

As a result of extensive research to develop a dyeing method using microwave heating that overcomes the above-mentioned drawbacks, the present inventor has found that:
We have discovered that when textile products are immersed in a dye solution containing a specific solvent and then heated with microwaves, it is possible to dye them quickly, stably and uniformly, and based on this knowledge, we have completed the present invention.

That is, the present invention provides a microprocessor method which is characterized in that the object to be dyed is immersed in a dye bath in which a dye is dispersed or dissolved in a mixture of water and an organic solvent having a boiling point higher than that of water, and then microwave heating is performed as it is. This is a dyeing method using wave heating.

The dyeing method of the present invention can be applied to all kinds of textile products such as synthetic fibers such as cotton, wool, and polyester fibers, as well as blended textile products and interwoven products.
As for dyes, all the dyes used for dyeing these textile products can be used.

Examples of organic solvents having a boiling point higher than water used in the present invention include ethylene glycol, glopylene glycol, dimethyl sulfoxide, diethyl sulfoxide,
Examples include dimethylformamide, diethylformamide, dimethylacetamide, benzyl alcohol, and nitrobenzenato (1) polar solvents.

Such a high boiling point organic solvent is used in combination with water in an appropriate ratio.

The ratio of this organic solvent to water is appropriately selected depending on the type of material to be dyed.
Since it can be dyed at around 00°C, the proportion of water should be increased, and if high temperature dyeing is required, such as with polyester, the proportion of water should be reduced.

In the method of the invention, the textile product is heated in the microwave while immersed in a dye bath.

At this time, the fibers are swollen by a large amount of the dyeing solution, and the microwave heating for a short time brings the fibers to a high temperature, which promotes dyeing inside the fibers and increases dyeing efficiency.

Furthermore, since the solvent does not evaporate from the fiber matrix, there is no problem of the temperature of the fiber matrix decreasing.

In this way, in the present invention, all the electromagnetic waves of the electric field are absorbed, so the thermal energy conversion efficiency is as high as about 80%.

In the method according to the invention, it is advantageous to control the bath temperature by taking a portion of the dyeing solution out of the electric field and circulating it.

As a method of circulation, for example, an outlet is provided at the bottom of one end of the dyeing container, an inlet is provided at the top of the other end, the outlet and inlet are connected through a pipe, and the dye solution is pumped up using a pump. For example, a method can be used.

Circulating the dye solution makes the heating temperature uniform and allows precise temperature control.

The method of the present invention is a dyeing method that is excellent in terms of energy saving because it uses the dye efficiently and can perform good dyeing with a small bath ratio by short-time microwave heating.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Direct Red 23
23) A solution obtained by dissolving 5 parts by weight of anhydrous sulfur salt in 10 parts by weight of water was mixed with 90 parts by weight of ethylene glycol to prepare a uniform dyeing solution.

A rice cloth (100'?/m) was immersed in this solution, and microwave heating was performed for 1 minute at a frequency of 2450 MHz and an output of 800 W using a fringing type microwave heating device while circulating the dye solution. A uniform red dyed fabric was obtained.

Example 2 Lanac o7 E-ro-4G (Larlacr
on Yellow 4G) 12 parts by weight, P#-3G (B
A dyeing solution was prepared by dissolving 0.8 parts by weight of C.lue 3G) and 3 parts by weight of urea in a mixed solution consisting of 95 parts by weight of dimethyl sulfoxide and 5 parts by weight of water.

A wool jersey was immersed in this solution, and microwave heating was performed for 1 minute and 30 seconds under the same conditions as in Example 1 while circulating the dye solution, yielding a dark green dyed fabric.

Example 3 Kayalon Polyester Blue 2GL-8 (Kaya
lon Polyester Blue 2GL-3)
A dyeing solution was prepared by dissolving 3 parts by weight in 97 parts by weight of dimethyl sulfoxide, adding 3 parts by weight of water, and adjusting the pH to 4.5 to 5 with acetic acid.

When polyester taffeta was immersed in this and microwave heating was performed for 1 minute at an output of 600 W while circulating the dyeing solution, a deep blue dyed cloth was obtained.

Example 4 Kayalon Polyester Blue 2GL-3 (Kaya
lon Polyester Blue 2GL-8)
A dyeing solution was prepared by uniformly dispersing 3 parts by weight in a mixed solution consisting of 99 parts by weight of ethylene glycol and 1 part by weight of water.

Polyester taffeta was immersed in this, and microwave heating was performed for 2 minutes at an output of 600 W while circulating the dye solution, resulting in a dark blue dyed cloth.

Claims (1)

[Claims] 1. An object to be dyed is immersed in a dye bath in which a dye is dispersed or dissolved in a mixture of water and an organic solvent having a boiling point higher than that of water,
A dyeing method characterized by microwave heating as is. 2. The method according to claim 1, wherein the organic solvent having a boiling point higher than water is ethylene glycol, propylene glycol, dimethyl sulfoxide, diethyl sulfoxide, dimethyl formamide, diethyl formamide, benzyl alcohol, or nitrobenzene.