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Application of Puffed Corn in Adhesive Production

Aug 14, 2019

First, the principle

Corn starch has 27% amylose and 73% amylopectin. Amylose is not a linear chain in the stretched state, but is curled into a spiral due to the action of intramolecular hydrogen bonds. This tightly packed coil structure of amylose is advantageous for the formation of intermolecular hydrogen bonds, which is not conducive to hydrogen bonding with water molecules, so amylose is not easily soluble in cold water. Amylopectin has a highly branched structure consisting of many short chains. Due to the highly branched structure of amylopectin, it is easy to form hydrogen bonds with water molecules. Therefore, amylopectin is easily soluble in cold water, but its bonding performance is poor. . That is, whether it is amylose or amylopectin, its bonding is not good, and it cannot be used directly as an adhesive. It must be oxidized or gelatinized before it can be used. The gelatinized starch has good initial adhesion and high bonding strength, and can be directly used as an adhesive.

At present, the gelatinization of starch is mainly heating gelatinization and alkali gelatinization. We have chosen another gelatinization method: puffing gelatinization, and the test effect is good. According to the principle of puffing, the pulverized corn granules are put into a puffing machine, and heated, pressurized and mechanically acted to make the corn in a high temperature and high pressure state. At this point, the sealing cover of the extruder is quickly opened. At this moment, because the corn is suddenly reduced to the normal temperature and normal pressure state, the huge energy is released, and the superheated water vaporizes and evaporates, and its volume can expand by about two thousand times. This creates an expansion pressure. The huge expansion pressure causes the corn tissue to undergo a powerful blasting extension, causing the corn to cause numerous tiny spongy structures, ie, the corn is puffed.

After being expanded, the corn is macroscopically expressed in the volume of corn several times to ten times, porous, spongy, loose texture; microscopically, the molecular structure of the internal structure and chemical composition of corn starch has changed, starch The hydrogen bonds between the chains break, the chains move, the starch granules disintegrate, degrade, and α-form. During the expansion process, as the starch is degraded, a part of the side chain of the amylopectin is cleaved, and the α-1,6-glycosidic bond breaks, which increases the proportion of the shorter amylose. Puffing not only leads to the degradation of amylopectin, but also causes the breakage of α-1,4 glycosidic bonds in amylose to produce small molecular substances, which is the dextrinization of starch. These have exposed the hydroxyl groups in the spiral circle to the outside, and the α-1,6-glycosidic bond with water breaks, increasing the proportion of shorter amylose. Puffing not only leads to the degradation of the branched starch, but also causes the breakage of the α-1,4 glycosidic bond in the amylose to produce a small molecular substance, which is the dextrinization of the starch. These expose the hydroxyl groups in the original spiral ring to the outside, and form hydrogen bonds with water molecules, making them less soluble in water and soluble in water. That is, the expanded corn starch has a loose structure, a sponge shape, and is easily soluble in water. Infiltrated, swelled in water, increased viscosity, enhanced initial adhesion, and markedly improved bonding strength, which allows the expanded corn starch to be used directly as an adhesive.

Second, the production process

1, process flow:

Corn → Peeling → Destruction → Lifting the umbilical → Treatment of borax aqueous solution → Puffing → Crushing → Screening → Quality inspection → Packaging. The process can be adjusted according to the actual situation. If corn starch is used, the process flow is simplified: corn starch → borax aqueous solution → puffing → pulverization → sieving → quality inspection → packaging.

2, operating points

The clean corn is peeled, smashed, and the corn germ is extracted to make corn granules. The quality is to be skinless and umbilical. The corn granules are directly placed in a puffing machine to be puffed, and after being puffed, they are pulverized by a pulverizer at any time, sieved, and 200 mesh fine powder is collected to obtain puffed corn starch. 70 kg of expanded corn starch can be obtained per 100 kg of corn.

Third, the application

1, wallpaper rubber powder

The wallpaper adhesive used to use white latex. Due to its poor frost resistance, winter use is limited. There are now a variety of wallpaper adhesives that have good adhesion but are costly. If puffed corn starch is used to formulate wallpaper adhesive, it has good bonding effect, low cost and convenient use.

Formula (quality score):

Puffed corn starch, 0 96; salicylic acid, 0 02; sodium pentachlorophenolate, 0 01; sodium diacetate, 0 01 .

After mixing and sifting, the package will be finished.

  Instructions : 

Take 1 kg of wallpaper rubber powder, add 1 kg of cold water, and mix well to get a paste of wallpaper glue. It is easy to use and easy to use. The product can be stored for a long time. The wallpaper it bonds is flat, the initial tack is good, the edges are not curled, the wallpaper does not change color, and it won't be wormed.

2, corrugated carton adhesive powder

The corrugated carton used to be foamed with a saponin because it is easy to return to moisture and is toxic. Many places have now been replaced by cornstarch adhesives. Corn starch adhesive is light in weight, strong in bonding strength and non-toxic, but its natural drying speed is too slow, which limits its universal application. The puffed corn starch adhesive has good initial adhesion performance, high bonding strength, fast drying speed and convenient use. Formulation (mass fraction): expanded corn starch, 0 83; potassium permanganate, 0 02; sodium hexametaphosphate, 0 02; sodium benzoate, 0 03; sodium bentonite, 0 10 . After mixing and sifting, the package will be finished. Usage: Take corrugated carton adhesive powder 1 kg and add 5 kg of cold water. Stir well and use. The usage is the same as that of foaming alkali. The adhesive has good flow rate when used, no glue, no running edge, no corrosion, no toxicity. 6 hours can be carried out in the next process, no burrs, no collapse, high hardness, light weight, high bonding strength.

3, oil field additives

The water-soluble polymers used in the oil field are mainly carboxymethyl cellulose, carboxymethyl starch, polyacrylamide, polyacrylic acid and the like. They play an important role in the suppression of scale in oil fields, water shutoff in oil fields, and increased oil production. Because puffed corn starch is easy to dissolve, sticky, high temperature resistant and low cost, it is an ideal substitute for the above products.

Formula (quality score):

Puffed corn starch, 0 75; sodium hexametaphosphate, 0 05; polyacrylamide, 0 07; sodium benzoate, 0 03; calcium bentonite, 0 10 .

After mixing and sifting, the package will be finished.

  Instructions : 

Take 1 kg of oil additive powder, add 4 kg of cold water, mix well and then inject it into the well with a pump. The auxiliaries can be much lower than the price of carboxymethyl cellulose. Because of its high viscosity and strong ability to adsorb mud, it can significantly increase crude oil production.

4, textile slurry powder

Before the sizing of the textile, the starch solution is often used and used by direct heating. It takes a lot of time and labor and consumes a lot of energy. Nowadays, a mixture of starch and polyvinyl alcohol is often used, which is inconvenient for application due to heating. It can be dissolved by adding cold water to the expanded corn starch, saving labor and time, saving energy and being very convenient to use.

Formula (quality score):

Puffed corn starch, 0 85; sodium tripolyphosphate, 0 05; oxidized polyethylene wax, 0 08; sodium benzoate, 0 02 .

After mixing and evenly sieving, the package will be finished.

  Instructions : 

Take 1 kg of textile slurry powder, add 20 kg of cold water, mix well and use. The usage is the same as the general textile slurry. Since the line of the slurry is soft and hard, the hand feel is good and the yarn breakage rate is significantly reduced.