LV10006B - Gypsum plasticizer of forming mixture - Google Patents

Abstract

The invention applies to civil engineering, it may be used to produce different kinds of binders for plaster form mixtures. The object of the invention is a form mixture plasticizing premix substance, which consists of naphthalene sulfonic acid, and the sodium salt mixture product of condensation of lignin sulfonic acid and formaldehyde, which is beforehand neutralized by sodium either potassium or hydroxide. To improve the plasticizing action of premix, strength and water resistance of the product, to reduce the corrosion, it is offered to neutralize the above-mentioned premix by sodium hydroxide and to modify it by potassium hydroxide, adding it in quantities that guarantee the plaster mortar water pH between 10-14 (in the second case, potassium hydroxide is added in 0.05-0.8 mass proportion).The offered premix plasticises form mixtures efficiently and reduces the binders' water necessity by 33-48 percent.

Description

PLASTIC PLASTIC PLASTER

The invention relates to construction and can be used to make gypsum moldings in the manufacture of building materials, in the manufacture of articles and structures in factories or on construction sites.

It is known to produce a mixture of gypsum raw material mixing gypsum push hydrate, carbonate, fibrous and plasticizing additive with water, initially mixing 80-90% by weight of admixture water and 80-90% by weight of plasticizing additive with plaster push, hydrate and carbonate the resulting mixture is poured with stirring, and the remaining admixture of water and plasticizer added is added with the addition of an acidic additive / 1 /.

The disadvantage of this type of raw material mixture is the low water resistance of construction products - the low softening factor Km.

The known gypsum gypsum binder with the raw material blend / 2 / from 15-30¾ dolomite content, oxalic acid, naphthalenesulfonic acid with formaldehyde condensation product, as well as sodium and potassium glass and glycerol also do not allow to increase the water resistance of the structures and products made according to this scheme.

The closest to the recommended invention, after the effect obtained by the addition of gypsum mortar additives, is the plasticizer C-3/3 / and its American analog - Lomar D / 4 / (prototype) modifying additive. Both C-3 and the modified additive Lomar D are based on high molecular weight condensation products of naphthalene sulfonic acids with formaldehyde (sulfated naphthalene-formaldehyde resin). these plasticizers differ in that the modified additive Lomar D is a mixture of potassium salts of naphthalene sulfonic acids with a formaldehyde condensation product and C-3 a mixture of sodium salts supplemented with lignosulfonic acid sodium salt.

Introducing the optimum amount of C-3 into 0.7% of the weight of binder in the plaster allows lowering the normal water-gypsum ratio of C-4 from 0.54 to 0.45 for the grade C-4 and 0.5% in C-3. - for gypsum push hydrate binder grade C-13 the normal water-gypsum ratio decreases from 0.39 to 0.33. Thus, the use of C-3 binders reduces the water requirement by up to 20%.

By applying the optimum amount of 0.25% modified Lomar D gypsum mortar from the powders, the water-gypsum ratio decreases from 0.35 to

0.28 / 4 / and thus the need for water is reduced by up to 23%.

The data presented indicate that the use of plasticizable additives C-3 and modified Lomar D does not reduce the water requirement of the gypsum binder to such an extent as to exclude the drying stage of molded and monolithic structural products.

The most significant disadvantage of the known plasticizing additives, including C-3 and modified Lomar D, is that their addition to the gypsum compound does not lead to a noticeable increase in the water resistance - softening factor by 10-20%. Another disadvantage of these plasticizer additives is that their addition does not lead to neutralization of the acidic environment of the gypsum mortar, which corresponds to a hydrogen ion activity index of pH = 7. Acidic environment is the cause of corrosion of gypsum products reinforcement,

The object of the present invention is to increase the plasticizing and strengthening effect of the gypsum mortar additive by increasing the water resistance (softening factor) of the gypsum products and reducing the corrosion of the reinforcement. The object is achieved with a plasticizing additive consisting of a condensation product of naphthalene sulphonic acid with formaldehyde and a sodium salt of lignosulphonic acid, by adding alkali KOH in such a way that in an aqueous medium prepared with the optimum amount of plastering additive 10 to 14.

The alkali is injected by mixing C-3 and KOH powders in proportions of 1 ppm. C-3: 0.05-0.8 ppm. KOH or by mixing the solutions of C-3 and KOH in the above proportions into dry matter.

The recommended plasticizer additive for MV can be applied to all possible gypsum binder compounds (uny3 ~ form push hydrate CaSO) anhydrite binder (CaSO) as well as in mixtures of different proportions of these binders.

The essential difference between the recommended additive MV and Lomar D, the chemical additive that is closest to its effect on the gypsum binder, is:

(1) the presence of hydroxyl ions,

(2) the simultaneous presence of potassium and sodium ions,

3) the presence of salts of lignosulfonic acid sodium.

Example of making and using a plasticizing additive.

To make the specific plasticizer additive, C-3 plasticizer powder and granulated alkali KOH (potassium hydroxide) are used in a weight ratio of 1 ppm. C-3:. 0.05-0.8 da.d. KOH. Mix dry ingredients thoroughly.

The ready-to-use powder plasticizer can be introduced directly into the water of the gypsum binder mix in an amount of 0.5-1.0¾ of the weight of the binder used.

If necessary, the plasticizing dry additive is pre-dissolved in water, adding not less than 4.6 da.w. water per 1 m.d. MV.

The plasticizer additive MV can also be made on the basis of liquid plasticizer C-3, which is manufactured industrially in the form of a 30% aqueous solution. Also, KOH is then made into a 30% concentration solution and then the two are mixed. For 1 L of C-3 solution use 0.28 L of KOH.

The composition compositions of the additive MV are shown in Table 1.

Table 1

Components * MV-1 MV-2 MV-3 Plasticizer C-3, m.d. 1 1 1 KOH ,, m.d. 0.8 0.2 0.6

* Calculation of C-3 and KOH for dry matter.

Table 2 shows, besides the gypsum and anhydrite binder characteristics used to test the effect of the plasticizing additive MV, the gypsum push hydrate binder characterization used in the prototype / 4 /. Table 2 also shows the results of exposure to optimum amounts of plasticizer additives C-3, Lomar D and modified Lomar D for gypsum binders, as well as examples of the application of various variants of MV additives. ₄

According to the data presented, the additive MV allows to reduce the water requirement of the gypsum and anhydrite binder by 33.4-48% depending on the type of binder, whereas the modified Lomar D additive does not reduce the maximum water requirement by more than 20%. The compression strength of gypsum products increases at least 1.89 times with MV, and even 3.5 times with some types of binders. With the prototype additive, the analogue strength increases by no more than 1.65 times.

The water resistance (softening coefficient Km) of plaster exhibitions increases by at least 32% when using MV, but no effect similar to the prototype is observed.

The recommended plasticizer additive MV exceeds all known analogues in the mortar from gypsum and anhydrite binders, and differs significantly from the prototype in increasing the water resistance (softening factor) of products made from gypsum and anhydrite binder.

The recommended plastering agent MV, in contrast to the prototype, reduces the acidity of gypsum and anhydrite binder mortars to pH 8-9 and contributes to reducing corrosion of gypsum products.

The effect of MV plasticizer additive on gypsum and anhydrite binder compounds is the result of complex action of components not present in the prototype.

Sources of information

1. USSR Author Certificate No. 1276645 AI C 04 B 1/00, 1983.

2. USSR Certificate of Author Nr. 1474122 AI C 04 B 11/024, 1986.

3. TY-6-36-0204229-625-90.

4. U.S. Pat. 4237260 C 08 6/00 1980 / Prototype /

Claims (2)

Formula of the Invention 1. A plasticizer for a gypsum formulation consisting of a mixture of naphthalene sulfonic acid with a formaldehyde condensation product and lignin sulfonic acid sodium salts, previously neutralized with sodium or potassium hydroxide, characterized in that, in order to increase plasticizing effect, product strength and water resistance and the mixture is first neutralized with sodium hydroxide and then modified with potassium hydroxide in an amount sufficient to guarantee the production of gypsum mortar in the pH range of 10 to 14. 2. A plasticizer according to claim 1, wherein the modifying potassium hydroxide is introduced in an amount of 0.05-0.8 parts by weight.