1 Introduction
Since the advent of reactive dyes, sodium alginate (SA) has been the main paste for reactive dye printing on cotton fabrics.
Using the three types of cellulose ethers CMC, HEC and HECMC prepared in Chapter 3 as the original paste, they were applied to reactive dye printing respectively.
flower. The basic properties and printing properties of the three pastes were tested and compared with SA, and the three fibers were tested.
Printing properties of vitamin ethers.
2 Experimental part
Test materials and drugs
Raw materials and drugs used in the test. Among them, reactive dye printing fabrics have been desizing and refining, etc.
A series of pre-treated pure cotton plain weave, density 60/10cm×50/10cm, yarn weaving 21tex×21tex.
Preparation of printing paste and color paste
Preparation of printing paste
For the four original pastes of SA, CMC, HEC and HECMC, according to the ratio of different solid content, under stirring conditions
Then, slowly add the paste into the water, continue stirring for a period of time, until the original paste is uniform and transparent, stop stirring, and place it on the stove
In a glass, let stand overnight.
Preparation of printing paste
First dissolve urea and anti-dyeing salt S with a small amount of water, then add reactive dyes dissolved in water, heat and stir in a warm water bath
After stirring for a period of time, add the filtered dye liquor to the original paste and stir evenly. Add dissolve until you start printing
Good sodium bicarbonate. The formula of color paste is: reactive dye 3%, original paste 80% (solid content 3%), sodium bicarbonate 3%,
Anti-contamination salt S is 2%, urea is 5%, and finally water is added to 100%.
printing process
Cotton fabric reactive dye printing process: preparation of printing paste → magnetic bar printing (at room temperature and pressure, printing 3 times) → drying (105℃, 10min) → steaming (105±2℃, 10min) → cold water washing → hot Washing with water (80℃)→soap boiling (soap flakes 3g/L,
100℃, 10min) → hot water washing (80℃) → cold water washing → drying (60℃).
Basic performance test of original paste
Paste rate test
Four original pastes of SA, CMC, HEC and HECMC with different solid contents were prepared, and Brookfield DV-Ⅱ
The viscosity of each paste with different solid content was tested by a viscometer, and the change curve of the viscosity with the concentration was the paste formation rate of the paste.
curve.
Rheology and Printing Viscosity Index
Rheology: MCR301 rotational rheometer was used to measure the viscosity (η) of the original paste at different shear rates.
The change curve of the shear rate is the rheological curve.
Printing viscosity index: The printing viscosity index is expressed by PVI, PVI = η60/η6, where η60 and η6 are respectively
The viscosity of the original paste measured by the Brookfield DV-II viscometer at the same rotor speed of 60r/min and 6r/min.
water retention test
Weigh 25g of the original paste into an 80mL beaker, and slowly add 25mL of distilled water while stirring to make the mixture.
It is mixed evenly. Take a quantitative filter paper with a length × width of 10cm × 1cm, and mark one end of the filter paper with a scale line, and then insert the marked end into the paste, so that the scale line coincides with the paste surface, and the time is started after the filter paper is inserted, and it is recorded on the filter paper after 30 minutes.
The height to which moisture rises.
4 Chemical Compatibility Test
For reactive dye printing, test the compatibility of the original paste and other dyes added in the printing paste,
That is, the compatibility between the original paste and the three components (urea, sodium bicarbonate and anti-staining salt S), the specific test steps are as follows:
(1) For the test of the reference viscosity of the original paste, add 25mL of distilled water to 50g of the original printing paste, stir evenly, and then measure the viscosity.
The obtained viscosity value is used as the reference viscosity.
(2) To test the viscosity of the original paste after adding various ingredients (urea, sodium bicarbonate and anti-staining salt S), put the prepared 15%
Urea solution (mass fraction), 3% anti-staining salt S solution (mass fraction) and 6% sodium bicarbonate solution (mass fraction)
25mL was added to 50g of original paste respectively, stirred evenly and placed for a certain period of time, and then measured the viscosity of the original paste. Finally, the viscosity will be measured
The viscosity values were compared with the corresponding reference viscosity, and the percentage of the viscosity change of the original paste before and after adding each dye and chemical material was calculated.
Storage Stability Test
Store the original paste at room temperature (25°C) under normal pressure for six days, measure the viscosity of the original paste every day under the same conditions, and calculate the viscosity of the original paste after 6 days compared with the viscosity measured on the first day by formula 4-(1). The dispersion degree of each original paste is evaluated by the dispersion degree as an index
Storage stability, the smaller the dispersion, the better the storage stability of the original paste.
Slipping rate test
First dry the cotton fabric to be printed to a constant weight, weigh and record it as mA; then dry the cotton fabric after printing to a constant weight, weigh and record it
is mB; finally, the printed cotton fabric after steaming, soaping and washing is dried to constant weight, weighed and recorded as mC
Hand test
First, the cotton fabrics before and after printing are sampled as required, and then the phabrometer fabric style instrument is used to measure the handiness of the fabrics.
The hand feeling of the fabric before and after printing was comprehensively evaluated by comparing the three hand feeling characteristics of smoothness, stiffness and softness.
Color fastness test of printed fabrics
(1) Color fastness to rubbing test
Test in accordance with GB/T 3920-2008 “Color fastness to rubbing for color fastness test of textiles”.
(2) Color fastness test to washing
Test according to GB/T 3921.3-2008 “Color fastness to soaping of textiles color fastness test”.
Original paste solid content/%
CMC
HEC
HEMCC
SA
Variation curve of viscosity of four kinds of original pastes with solid content
are sodium alginate (SA), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC) and
Viscosity curves of four kinds of original pastes of hydroxyethyl carboxymethyl cellulose (HECMC) as a function of solid content.
, the viscosity of the four original pastes increased with the increase of solid content, but the paste-forming properties of the four original pastes were not the same, among which SA
The pasting property of CMC and HECMC is the best, and the pasting property of HEC is the worst.
The rheological performance curves of the four original pastes were measured by MCR301 rotational rheometer.
- Viscosity curve as a function of shear rate. The viscosities of the four original pastes all increased with the shear rate.
increase and decrease, SA, CMC, HEC and HECMC are all pseudoplastic fluids. Table 4.3 PVI values of various raw pastes
Raw paste type SA CMC HEC HECMC
PVI value 0.813 0.526 0.621 0.726
It can be seen from Table 4.3 that the printing viscosity index of SA and HECMC is larger and the structural viscosity is smaller, that is, the printing original paste
Under the action of low shear force, the viscosity change rate is small, and it is difficult to meet the requirements of rotary screen and flat screen printing; while HEC and CMC
The printing viscosity index of CMC is only 0.526, and its structural viscosity is relatively large, that is, the original printing paste has a lower shear force.
Under the action, the viscosity change rate is moderate, which can better meet the requirements of rotary screen and flat screen printing, and can be suitable for rotary screen printing with higher mesh number.
Easy to get clear patterns and lines. Viscosity/mPa·s
Rheological curves of four 1% solids raw pastes
Raw paste type SA CMC HEC HECMC
h/cm 0.33 0.36 0.41 0.39
The water holding test results of 1%SA, 1%CMC, 1%HEC and 1%HECMC original paste.
It was found that the water holding capacity of SA was the best, followed by CMC, and worse by HECMC and HEC.
Chemical Compatibility Comparison
Variation of the original paste viscosity of SA, CMC, HEC and HECMC
Raw paste type SA CMC HEC HECMC
Viscosity/mPa·s
Viscosity after adding urea/mPa s
Viscosity after adding anti-staining salt S/mPa s
Viscosity after adding sodium bicarbonate/mPa s
The four primary paste viscosities of SA, CMC, HEC and HECMC vary with the three main additives: urea, anti-staining salt S and
The changes in the addition of sodium bicarbonate are shown in the table. , the addition of three main additives, to the original paste
The rate of change in viscosity varies greatly. Among them, the addition of urea can increase the viscosity of the original paste by about 5%, which may be
It is caused by the hygroscopic and puffing effect of urea; and the anti-staining salt S will also slightly increase the viscosity of the original paste, but it has little effect;
The addition of sodium bicarbonate significantly reduced the viscosity of the original paste, among which CMC and HEC decreased significantly, and the viscosity of HECMC/mPa·s
66
Secondly, the compatibility of SA is better.
SA CMC HEC HECMC
-15
-10
-5
05
Urea
Anti-staining salt S
sodium bicarbonate
Compatibility of SA, CMC, HEC and HECMC stock pastes with three chemicals
Comparison of storage stability
Dispersion of daily viscosity of various raw pastes
Raw paste type SA CMC HEC HECMC
Dispersion/% 8.68 8.15 8. 98 8.83
is the dispersion degree of SA, CMC, HEC and HECMC under the daily viscosity of the four original pastes, the dispersion
The smaller the value of degree, the better the storage stability of the corresponding original paste. It can be seen from the table that the storage stability of CMC raw paste is excellent
The storage stability of HEC and HECMC raw paste is relatively poor, but the difference is not significant.
Post time: Sep-29-2022