The preparation process of chemicals has a crucial influence on their final performance. Various factors such as preparation method, selection of raw materials, reaction conditions and purification process will directly affect the purity, stability and functionality of chemicals. In addition, the process technology and equipment used in the preparation process also determine the quality and application effect of chemicals to a large extent. Therefore, optimizing the preparation process of chemicals is a key link to improve their performance and application value.

Qingdao JIERUIXIN has always been professional in the selection and preparation of chemicals. After years of research, the deployment of the most likely to meet the needs of paper coating chemicals. Their professional team continues to optimize the chemical formulations to ensure that each product has excellent performance. It is also equipped with an advanced chemical preparation system, strictly controlling every step, from raw material processing to the final product, to ensure that every part of the coating process is perfect. This professional and fine process ensures the high quality and stability of its products, making it a strong competitiveness in the market.Based on their years of experience, the following conclusions can be drawn about the preparation of chemicals:

1.Datinization process of modified starch

(1) gelatinization concentration: generally between 10% and 20%;

(2) Dilematinization requirements:

① First, add a certain amount of water to the gelatinization tank, and start the mixer;

② Add the measured modified starch, and disperse the modified starch evenly;

③ Heat the steam to 85~90℃, close the steam valve, and continue to keep warm for 10~15 minutes;

④ After the insulation, open the layer cooling water valve of the gelatinization tank layer, and close the cooling water valve after the pasting liquid temperature is cooled to normal temperature;

⑤ The preservative is diluted with a certain amount of water and added to the gelatinizing liquid, further stirring for 3~5 minutes, and finally the gelatinization liquid is filtered and placed in the gelatinizing liquid storage tank for use.

2.Carboxymethyl cellulose sodium (CMC), dissolution process

(1) Dissolution concentration: generally about 10%;

(2) Dissolution requirements:

① First add a certain amount of water to the dissolution tank and start the mixer;

② Sprinkle CMC evenly under stirring, stir for more than 10 hours after CMC addition, so that CMC and water are fully fused and fully dissolved. Finally, filter CMC dissolution solution and put it in the CMC dissolution solution storage tank for use.

3.Preparation of CB coatings

(1) Add a certain amount of water to the CB coating mixing tank and disperse it Good spacer and dispersant, start the mixer stirring for 5 minutes; (2) Add measured starch paste, microcapsules, carboxylic styrene emulsion, CMC in the CB coating ingredient tank in order, and continue to stir for 10~15 minutes; (3) filter the above prepared CB coating and place it in the CB coating storage tank.

4.Preparation of CF coatings

1.Divergence of pigments

CF paint pigments generally for kaolin and light calcium carbonate, two kinds of pigment property is different, meet the requirements of dispersion time is different also, kaolin than light calcium carbonate, conditions allow two pigments best respectively, but the practice of most manufacturers is usually the two pigments together.

The pigment dispersion process is as follows:

(1) Add a certain amount of water, foam inhibitor and dispersant to the CF coating dispersion tank first, and start the mixer for stirring for 2~3 minutes;

(2) Add calcium carbonate and kaolin respectively (the concentration of pigment dispersion liquid is generally 55%~60%);

(3) Increase the stirring speed and continue to stir at high speed for at least 70 minutes.

2.Mix of each component of CF coating

(1) Transfer the dispersed pigment mixture to the CF coating mixing tank.

(2) Add residual water, starch paste, chromogen, carboxylic styrene latex, CMC dissolution solution and lubricant to the CF paint mixing tank;

(3) Start the CF coating mixing tank mixer, and add caustic soda for 10~15 minutes to adjust the pH value;

(4) Filter the prepared CF coating and place it in the CF storage tank.

Paint performance

1 Performance of CB coating

(1) Solid content of 18%~23%;

(2) Viscosity: 13.0 ~ 17 cp;

(3) pH value: 7. 5~8. 0.

2 Performance of CF coatings

(1) Solid content of 23%~26%;

(2) Viscosity: 25 ~ 35 cp;

(3) pH value: 8. 0~8. 5

Problems to be noted in the coating preparation process

1. In the batching process (pigment dispersion and component mixing), the partition cooling water of the dispersion tank and batching tank must be opened.

2. Preparation of paint and addition of color material in the production of color paper:

(1) If the color material is a powder (solid), the color material should be dissolved in water and added to the pigment high-speed dispersion tank together with the pigment high-speed dispersion;

(2) If the color material is liquid, the color material is diluted in water and added in the paint mixing tank.

3. If conditions permit, it is recommended that kaolin be separated from light calcium carbonate.

4. At present, most manufacturers of coating filtration equipment use round vibrating screen.

5. The pH value of general CF coating is controlled at 8. 0~8. 5, so the viscosity is moderate, the mobility and stability are good; the quality of carbon carbon paper is also good.

6. The spacer must be pre-dispersed before adding CB coating ingredients tank, the pre-dispersion concentration is generally 20%, the high speed disperser is used for dispersion, and the appropriate amount of dispersant can also be added when the spacer is pre-dispersed.

7. The use of modified starch in CB and CF coatings is because the starch has good water retention and does not form a film, so that the coating is in an open state, which is helpful to improve the color rendering effect of carbon-free carbon paper.

8. Paint flow generally uses screw pump, and a few manufacturers use diaphragm pump.

9. The foam suppressing agent in CF coating should not be added in excess, otherwise it is easy to cause the coated paper to produce fish eyes (white dots), especially when the production of color carbon-free carbon paper.