Adhesive formulation and production process, such good content can not be shared by me alone!

The quality and dosage of the adhesive have a great relationship with the quality and dosage of starch, and the fineness of starch, protein and fat content all affect its performance. If the protein and fat content in the starch is too high, the fineness is less than 98 mesh (100 mesh filter), even if the oxidation degree is very high when making, the viscosity of the material is only twenty seconds (coated -4 cup viscosity meter measurement). But storage for 5-7 days or so will naturally thicken, lose fluidity,

. When using foam is also large, directly affect the quality of bonding, and the use of qualified starch, as long as the degree of oxidation and paste appropriate, made of adhesive finished viscosity of 40 to 10 seconds, storage period viscosity will not change much, but the color dark, but the viscosity basically unchanged.
amount of starch according to the specific requirements of the adhesive object and change
(1) single-sided corrugated cardboard with adhesive coating, the adhesive requirements are low, starch dosage: 150-170 kg / ton of water.
(2) high-strength corrugated paper on both sides of the glue, the adhesive requirements are higher, starch dosage 170-200 kg / ton of water.
(3) ordinary corrugated paper and grass pulp corrugated paper on both sides of the glue and cardboard and cardboard composite, the adhesive requirements are relatively high, starch dosage 180-300 kg / ton of water.
(4) automatic veneer machine and paper tube glue, adhesive has special requirements, in addition to fast drying, but also requires good bonding, high strength, starch dosage: 200-350 kg / ton of water.
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . NaOH aqueous solution, as long as the purity is qualified, any state of alkali can be used, soda dosing to add oxidizing starch stirring 20 minutes starch liquid for translucent paste so far, the amount of soda is too large, the fluidity of the glue is large Good transparency, storage time is long, but corrugated peak glue in the alkali content will also increase, made of corrugated cartons easy to reverse yellowing, resulting in corrugated carton surface ink color change; The amount of soda from the actual observation, generally about 12% of starch is more appropriate.
2, oxidants
starch adhesives, commonly used oxidants are hydrogen peroxide, sodium hypochlorate, potassium permanganate and so on. Potassium permanganate as an oxidant, the amount is easy to grasp, made of starch adhesive finished quality is also stable, but made of starch adhesive color for dark coffee or brown black. Sodium hypochloride and hydrogen peroxide as an oxidant to produce starch adhesive color pale yellow, but sodium hypochlorate starch adhesive in the use of unstable quality, decomposition of chlorine gas, so that operators feel eye discomfort; In addition, sodium hypochlorite in the sun or high temperature easy to break down, reduce the chlorine content, in the application to keep track of its exact content and moderately increase the dosing. From the use of analysis, the use of hydrogen peroxide as an oxidant, stable quality, small dosage, low cost, rapid reaction is the ideal material for use as an oxidant.
In the production of cold high-strength fast-dry starch adhesive, oxidation reaction played a key role, oxidation is appropriate (20-40 minutes after added soda viscosity of 60-80 seconds), starch dissolution performance improved, film-forming capacity is good, strong bonding force; , after adding soda, for a long time are constantly thin, or even the phenomenon of stirring (add soda reaction for more than 40 minutes, viscosity is higher than 100 seconds), so that the need to add oxidants for secondary oxidation, such as excessive oxidation, starch ring structure open chain, adhesion is low, or even lose the adhesion capacity (after adding soda reaction 20 minutes viscosity less than 40 seconds). Therefore, special attention should be paid to the use of oxidant content and ratio.
oxidation process temperature also played a role, the higher the temperature, the faster oxidation, summer general oxidation reaction 10-15 minutes, spring and autumn oxidation reaction 15-20 minutes, winter oxidation reaction 30 minutes or so, oxidation reaction time extended, oxidation complete, product quality is stable, but too long will affect the production cycle.
the specific dosage of
oxidants varies with starch, the amount of starch is small, the amount of oxidants is also small, the amount of sodium hypochlorate (10%) is about 28% of starch, the content of hydrogen peroxide (27.5%) is about 4% of starch, and the amount of potassium permanganate is about 2% of starch. The method of determining whether oxidation is appropriate is to stir for 20-40 minutes after adding soda, and to measure its viscosity of about 60 seconds (summer). The finished product is stored for about 2 hours, with a viscosity of about 50 seconds, and stabilizes at 40 to 10 seconds after one day. In addition, winter temperature is low, oxidant dosage should be appropriately increased, summer temperature is high, the reaction is fast, the dosage is appropriately reduced.
3, strong solid catalyst (desiccant)
cold high strength fast dry series starch adhesive is different from other adhesives, the main factor is the choice of "strong solid catalyst." Strong solid catalyst is composed of several salts and organic inorganic compound polymerization reaction, in the adhesive production process, as long as the appropriate amount of time, not only speed up the reaction speed, but also after the application of the glue through the polymer and oxygen in the air chemical reaction, quickly flocculation crystallization, but also speed up the adhesive film, shorten the drying time of cartons, improve the strength of cardboard. Therefore, the adhesive bonding speed (initial adhesion, full stickiness, damage fiber) is more than several times higher than similar starch glue. And cardboard hardness is high, good stiffness, strong solid catalyst dosage in the adhesive per ton of water dosage less than 5kg does not play its due role, per ton of water dosage is higher than 15kg, adhesive conjunctivation is too fast, easy to produce cardboard degluing phenomenon. Therefore, we should strictly control the delivery ratio. The normal dosage standard is 6-12kg/tonne of water.
4, crosslinker
adhesive paste after adding borax or boric acid, it can make short chain oxidizing starch with its hydroxyl and boron atoms form a complex, through these irregular crosslinking, the formation of a mesh structure, with Cross-linking to increase the adhesive effect, is conducive to improve the initial adhesion and speed up the drying speed, but also play an anti-corrosion impermeability and termination of the reaction effect, but the amount is not the more the better, too much will make the adhesive flow worse than adhesive frozen, difficult to glue, adhesive brittle. Too little complexing is not enough, poor bonding force, causing corrugated cardboard de-glue and run-corrugated phenomenon.
20-40 minutes after stirring after oxidation of starch paste, if the viscosity is about 60 seconds, can be further added borax solution, such as sticking through the high more than 100 seconds, can be added oxidant for two Suboxidation, after stabilization of the viscosity of 50 seconds (generally 2-3 hours), and then add borax solution, such as less than 100 seconds, can stabilize 2 hours after the appropriate water conditioning to about 60 seconds plus borax solution.
borax effective boron content of 11.32%, boric acid effective boron content of 17.48%, in the application, boric acid dosing can be reduced by nearly 1/3 compared to borax, borax dosing is generally 3-3.5% of starch, boric acid dosing is generally 2-3% of starch.
5, defrost
in the production and use of the process due to starch quality and reaction is not appropriate, will produce a lot of foam, affecting the normal application of glue machine, especially with hydrogen peroxide as an oxidant, more prone to foam, so that the appropriate amount of defrosting agent de-foaming. Deblants can be used in silicone oil or triglycerides phosphate, orthool, etc. Using sodium hypochlorate or potassium permanganate as an oxidant, the amount of triclosan phosphate was 0.01-0.03% of the amount of glue, and the amount of triclosan phosphate with hydrogen peroxide was 0.03-0.05% of the amount of glue.
Pay special attention to the amount of defrosting agent should not be too much, excessive will make the surface of the adhesive pressure reduction, loss of viscosity, bonding strength can not meet the requirements, in production, such as glue machine foam too much, it is best to stop to add a little desolation to the glue tank stirring uniformly, start trial, such as foam more, and then add a little, until it can run normally, but a little, do not add anti-foaming agent to the upper glue roll. Earth method to observe whether the defrosting agent is appropriate to put starch glue in a high transparency glass bottle, shake hard for about 2 minutes, immediately stop, observe the foam on top of the glue in the bottle, such as 20-30 seconds on the glue on the large foam disappeared, that is, the amount of defrosting agent can be used, can be glued to use;
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