Types, Development and Synthesis of Wet Enhancers (2)

(a) Synthetic method of PPE resin

The polyamide polyamine epichlorohydrin resin is abbreviated as PPE, also known as polyamide polyamine epichlorohydrin resin or polyamide-epichlorohydrin resin. PPE is a water-soluble, cationic, thermosetting resin, non-formaldehyde polymer, non-toxic and tasteless, can be used in the pH range of 4-12, with good wet strength. It is characterized by low dosage, suitable for neutral papermaking, and easy handling of broke paper. It can also be used as a flocculant to treat factory wastewater.

1. Quality index of PPE resin: Appearance: light amber particle liquid, solid content: 12.5%±0.3%, specific gravity: 1.03kg/l, viscosity: 40-60cps, freezing point: -1°C, pH4.6-4.9 .

2, PPE resin chemical synthesis method is mainly divided into two steps, the first step to the first synthesis of polyamide, the second step to polyamide as raw material to generate PPE resin. Divinyltriamine and triethylenetetramine can also be used in the synthesis of polyamides.

3. Raw materials: Diethylenetriamine 103g (triethylene tetraamine 146g)

Oxalic acid 146g

Epoxy chloropropane sulfone 80g (When using triethylenetetramine, take epichlorohydrin 76 points 4g)

Water amount

10% hydrochloric acid (or sulfuric acid) amount

10% sodium hydroxide amount

4, utensils: open enamel bucket (or three-necked flask), stirrer, glass rod, alcohol lamp (or electric heater), balance (table), measuring cylinder, beaker, viscometer.

5, process conditions: normal temperature and pressure.

6, synthesis method:

first step. Diethylenetriamine 103g (or triethylene tetraamine 146) was taken and placed in an open enamel bucket (or three-necked flask). The stirrer was started and 31 g of water was added. Then slowly add 146g of oxalic acid, at which time the temperature rises to 115-120C. After stirring evenly, start heating and raise the temperature to 130C. At this time, it is necessary to pay attention to the insulation for about half an hour to prevent the foam from overflowing. After the foam disappeared, it continued to heat up to 190-200°C and hydrated for about 1.5-2 hours. The heating was stopped. When the temperature dropped below 160°C, water was slowly added to make the total amount 400 g. At this point, the solid content of the resin is about 50%, and the resin is ready for use after being stirred evenly. The yield of the resin is about 85%.

The second step. To the polyamide liquid prepared in the first step, 600 g of water was added thereto, stirred and 80 g of epichlorohydrin was added dropwise, and the addition was completed in about 3 to 11 minutes. When the heating is started and the temperature is raised to 75C, the heating is stopped, and the stirring is continued. When the viscosity is measured to 25-30 centipoise (solid content 19%), 10% hydrochloric acid (or sulfuric acid) is added immediately to adjust the pH to 4-5, and it can be stored for use.

third step. When used, it is first adjusted to pH 6-7 with 10% sodium hydroxide solution, diluted with appropriate amount of water, and added to the slurry tank after stirring.

7. Note:

(1) The reaction of diethylenetriamine (or triethylenetetramine) with acetic acid is carried out at 160°C-210°C under atmospheric pressure for 0.5-2 hours with a molar ratio of amine to acid of 0.8:1-1.4:1. Preferably, gelling occurs at 0.9:1 to 1.2:1, less than 0.8:1, and greater than 1.4:1 yields a low molecular weight polyamide.

(2) When the polyamide reacts with epichlorohydrin, the temperature is about 45°C to 70°C, and the viscosity is greater than 0.85 centipoise. The reaction is preferably carried out in an aqueous solution to moderate the reaction, usually without adjusting the pH, but the pH during the reaction The value will be reduced. If necessary, the addition of an acid generated in the alkali neutralization unit will favor the conversion of the chlorohydrin group to the epoxy group. When the desired viscosity has been reached, it is diluted with water to make the content of the resin solution about 10%, and cooled to 25°C, and then pH is adjusted to pH 5-6 to make it stable, preferably up to pH=5. The use of 1.0-1.5 moles of epichlorohydrin per secondary amine group of the polyamide gives satisfactory results.

(3) When using PPE resin, the pH should be adjusted to 7-8 with 10% sodium hydroxide, so that it can be activated. PPE resin can be directly added to the slurry. The range of addition is 0.1%-5% (for dry fiber ).

(4) Avoid contact with concentrated acid when using PPE resin.

8. Storage method: PPE resin should be stored in a cool, ventilated and dry place. Try to avoid freezing and high temperature (>32°C). The storage temperature should be higher than 4.4°C. If the product is melted and melted, it should be mixed evenly and used immediately; in the environment below 32°C, it can be stored for 3 months, and the wet strength effect will be reduced for more than 3 months. The general storage period is 6 months.