Urea formaldehyde foam

DATE：2022/6/18 8:46:33 / READ： / SOURCE：This station

Urea formaldehyde foam

Urea formaldehyde resin is made from urea and formaldehyde by heating and polycondensation in acidic or alkaline medium. Urea formaldehyde plastic powder can be divided into powder molding powder (P), granular molding powder (g), fibrous molding powder (f) and granular molding powder for injection (I) according to its characteristic properties; According to the purpose, it can be divided into general purpose (a), tableware, with heat resistance (b), electrical, with good dielectric properties (c), and other special properties (E). Hollow plate production line www.handern com
Urea formaldehyde foam is a white block foam made of urea formaldehyde resin as raw material, sodium dibutyl naphthalene sulfonate (commonly known as Kaila powder) as surfactant, foam is formed by mechanical stirring, cured under the action of catalyst, and then dried. Its biggest advantages are light weight, low thermal conductivity and low price. It is widely used in industries, agriculture, transportation and national defense industries, such as trains, ships and automobiles. Urea formaldehyde foam has the disadvantages of strong water absorption and low mechanical strength, so it is generally not used as a structural material. Hollow plate production line www.handern com
1、 Raw materials
(1) Resin urea formaldehyde resin is a resin solution formed by the reaction of urea and formaldehyde in a certain proportion in weak acid, which is then mechanically stirred and continuously inflated into the air, reducing the surface tension of the system under the action of surfactant, making the air easy to disperse in the solution, thus forming numerous dense bubbles. At the same time, polycondensation was continued under the action of oxalic acid and phosphoric acid
The resin can also be added with additives such as filler (cellulose), pigment, curing agent and stable homogeneous plasticizer to prepare aldehyde plastic powder through kneading, drying, crushing, ball milling, sieving and other processes
(2) Generally, sodium dibutyl naphthalene sulfonate (Kaikai powder) is used as the hair agent, and the dosage is 2%~10%. This is an anionic surfactant. Currently, Kaikai powder BX and bx-78 hollow plate production lines are available www.handern com
(3) Generally, the hardener is a mixture of phosphoric acid and oxalic acid. The amount of phosphoric acid used alone is 15% of that of foaming agent solution. The amount of phosphoric acid used together with oxalic acid can be appropriately reduced. Hollow plate production line www.handern com
(4) Isophthalic acid is often used as stabilizer, and phenol can also be used as stabilizer. The dosage should be twice that of resorcinol.
(5) Its additives, plasticizers, lubricants, water, etc.
2、 Production process
The production process of urea formaldehyde foamed plastics includes six processes: preparation of urea formaldehyde resin solution, preparation of foaming solution, foaming, pre molding, drying and cutting. The production process is shown in Figure 8-1. The casting and forming equipment of urea formaldehyde foam plastic is shown in Figure 8-2.
Sodium glycine hexamethylene tetramine sulfonate butyl benzene urea water sodium sulfonate dibutyl benzene urea with acid blowing agent without acid blowing agent dilution foaming curing drying processing packaging hollow board production line www.handern com
1. manufacture of urea formaldehyde resin
First, add formaldehyde aqueous solution into the reactor, and adjust its pH value to 6.4~6.5 with 10% sodium hydroxide solution, then add urea and glycerin under the condition of stirring and reflux, heat the reaction mixture to boiling within about 1H, and reduce the pH value of the mixed solution to 5.0~5.5 with 10% formic acid aqueous solution after 15min. Continue the reaction under boiling until the viscosity of the mixture reaches 0.025~0.030mpas. Neutralize with sodium hydroxide solution to raise the pH value of the reaction mixture to 6.8~
7.0。 Cool to 20~30 ℃ and put the solution into the aluminum storage tank for standby. 2. preparation of foaming agent solution
Weigh a certain amount of pulling powder and water according to the formula, put them into the preparation pot, start the mixing and heat them with steam in the jacket. When the reaction temperature reaches 70~80 ℃, add the dissolved phenol solution and continue stirring for 1H; After all dissolves, add the reactant into the acid free foaming agent high-level tank for standby. The acid foaming agent is prepared according to the formula, and the operation method is the same as the above.
2. preparation of foaming agent solution hollow board production line www.handern com
Weigh a certain amount of pulling powder and water according to the formula, put them into the preparation pot, start the mixing and heat them with steam in the jacket. When the reaction temperature reaches 70~80 ℃, add the dissolved phenol solution and continue stirring for 1H; After all dissolves, add the reactant into the acid free foaming agent high-level tank for standby. The acid foaming agent is prepared according to the formula, and the operation method is the same as the above.

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