JPS60127256A - Plaster composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plaster composition with excellent self-smoothing properties. More specifically, the present invention relates to a plaster composition characterized by blending an acrylic emulsion and cement.

Conventionally, in floor repair work for buildings, sandblasting and mortar finishing were performed to adjust the uneven floor surface after the floor surface material had been peeled off, which required a long process and construction period. Recently, self-smooth flooring materials (self-leveling flooring materials) have been used, but the surface smoothness of self-leveling flooring materials with uneven surfaces is maintained when the pouring thickness is 10 to 8 Off. This is because it has the following performance. Therefore, there is a long-awaited development of a flooring material that has sufficient self-smoothness even when the pouring thickness is thin, and it is expected that this will shorten the repair work process and construction period.

Self-smoothing plaster compositions based on gypsum that have been proposed so far include those to which a dispersant and a water collecting agent are added, and those to which an aqueous emulsion is added.

An example of the former is described in Japanese Patent Publication No. 54-16972°, which states that alpha hemihydrate gypsum is used as a base material, a sulfonic acid dispersant and a phosphate ester surfactant are used as dispersants, and a dispersion aid. A plaster composition that uses alkali sulfate as an alkali sulfate and also contains a water retention agent and an antifoaming agent has self-smoothing properties and has a slump value (flow value in the present invention).

(same below) was 16 to 17 crn. However, the flow value is 4o-? This is the value obtained by measuring the radius when the pipe is pulled up after j and the slurry is spread into a circular shape. When this slurry was poured into two construction areas with an average pouring thickness of 20a, the horizontal surface accuracy after hardening was ±1.20 (lQQn
+ interval).

By the way, in the case of a flow value of 16 to 17 cm by the above method, the average thickness after spreading into a circular shape is 2.7 to 2.4 m.
It is calculated as l. Therefore, in the case of thin casting with a casting thickness of 2.0 fl or less, the self-smoothness is not sufficient and it is necessary to use a brush or a trowel. Further, although various changes were made in the concentration of additives within the scope of this example, there were no conditions that satisfied all of the flow value, compressive strength, solid-liquid separability, etc. Japanese Patent Publication No. 52-89846, which is an example of the latter, describes a composition consisting of plaster and emulsion in such a proportion that when the plaster solidifies, it absorbs most of the water in the emulsion. has self-smoothness, flexibility, non-shrinkage, water resistance, etc. By the way, no fixed data regarding self-smoothness are given in this example, but "even on slightly inclined and uneven surfaces it is possible to obtain an equally horizontal layer with a thickness of about 3.2 mm. Judging from the statement ``, it seems that self-smoothness is insufficient in this example as well in the case of bookkeeping. In addition, the amount of emulsion (solid content 40-56%) used is 12-6
A large number of 2% is not preferable because it increases the cost and is disadvantageous in terms of fire resistance.

In view of the above-mentioned current situation, the present inventors have made extensive studies and have found that by blending a specific emulsion and cement with plaster, self-smoothness can be significantly improved, and the present invention has been completed. That is, as a result of the studies conducted by the present inventors, the following has become clear.

(1) Increasing the amount of crosstalk water improves the flow value, but the strength decreases, floating ice occurs, and the expansion rate increases.

(2) When the dispersant is increased, the flow value does not change much;
Expansion rate increases.

(3) When an acrylic resin emulsion is added, the flow value improves and no decrease in strength is observed, but the expansion rate increases.

(4) Adding cement has an expansion suppressing effect.

From these results, we found suitable conditions for the combination of acrylic resin emulsion and cement that improve the flow value and do not reduce physical properties such as strength, expansion rate, solid-liquid separation, and completed the present invention. reached.

That is, in the present invention, the acrylic resin emulsion has a resin solid content of 0 with respect to 100 parts by weight of α-hemihydrate gypsum.
．． 4 to 4.0 parts by weight, 0.2 to 2.0 parts by weight of cement, and 27 to 40 parts by weight of water. The present invention relates to a plaster composition containing one or more of an inhibitor, an antifoaming agent, a water retention agent, an aggregate, etc., as required.

The α-type hemihydrate gypsum used as a base material raw material in the present invention usually has a standard mixed water content (according to JIS-R-9112) of 2.
7 to 50% by weight is selected, and those with a weight of 42 or less are particularly desirable. Although the particle size distribution of α-type hemihydrate gypsum is closely related to the standard amount of mixed water, it is not particularly restricted in the present invention.

The acrylic resin emulsion has a polymerizable seven polymer (
Methyl acrylate (consisting of Meester 1 and one or more 4-acrylic esters, or styrene added), which is emulsion polymerized. Usually particle size 0.1 to 8 μm, solid content. It is 30 to 60% by weight.

6- Toughtic ■R-1 as an example of a commercially available product that is suitably used
08 (manufactured by Japan Exlan), Polytron A1221 (
(manufactured by Fukkasei) etc. are used. Addition amount is α hemihydrate gypsum 10
0.4 to 4.0 parts by weight is used as the resin solid content with respect to 0 parts by weight. If the amount is less than this range, the effect of addition will not be exhibited, and if it is added beyond this range, it is unfavorable from the viewpoint of fire resistance and cost. Preferably, 0.8 to 1.2 overlapping parts are used.

The cement used is usually Portland cement, white cement, etc., and the amount added is 0.2 to 2.0 parts by weight per 100 parts by weight of α-hemihydrate gypsum. If the amount is less than this range, the effect of addition will not be exhibited, and if it is added beyond this range, the slump value will decrease. Preferably 0.4-1
．． 5 parts by weight are used.

The dispersant used as an additive is effective for loosening particles such as α-type hemihydrate gypsum into primary particles and improving initial fluidity. As the dispersant used in the present invention, ordinary dispersants for cement mortar are used, but sodium ligninsulfonate, calcium ligninsulfonate,
β-naphthalene sulfonic acid formaldehyde condensate sodium salt, β-creonate sulfonic acid, cresol sulfonic acid condensate, melamine formaldehyde condensate sulfonate and sulfite, polyacrylic dispersant, phosphate ester surfactant, etc. is given as a typical example. These dispersants can be used alone or in combination of two or more, if necessary.

The amount of the dispersant added varies depending on the type of dispersant used and whether or not it is used in combination with a phosphate ester surfactant, but it is usually 0 to 100 parts by weight of α-type hemihydrate gypsum etc.
．． 1 to 10 parts by weight are used. If used in a large amount exceeding this range, the fluidity may decrease or the setting and hardening properties may be adversely affected. Preferably it is 0.15 to 5 times.

There are various expansion inhibitors, but alkali metal sulfates are effectively used from the viewpoint of further enhancing the effect of the dispersant, improving the setting and hardening properties, and further increasing the fluidity of the slurry. . Among the alkali metal sulfates, potassium sulfate and sodium sulfate are selected from the viewpoint of economic efficiency. The added acid of alkali metal sulfate is α
The amount is about 0.2 to 8.0 parts by weight per 100 parts by weight of mold hemihydrate gypsum, etc.

If it is less than this range, the expansion suppressing effect will be insufficient, and if it exceeds this range, setting and hardening will be extremely rapid, resulting in a marked decrease in workability.

Setting regulators are used to adjust the gelation start time, and for α-type hemihydrate gypsum, there are various slowing agents such as various phosphates, various carboxylic acids, and various proteins, but depending on the amount added, The gelation time can be adjusted arbitrarily.

The water retaining agent is used to prevent solid-liquid separation before the slurry begins to gel. Although the amount of water-retaining agent added is not necessarily uniform depending on the type of water-retaining agent, in general, adding a water-retaining agent increases the viscosity of the slurry. Since this also functions as a so-called viscosity modifier, care must be taken in the amount added so as not to reduce the initial fluidity of the slurry. Water retention agents include cellulose, vinyl, and acrylic, and cellulose is widely used, but methyl cellulose is particularly preferred.The amount added is 2.0 parts by weight per 100 parts by weight of α-type hemihydrate gypsum, etc. If it is outside this range, the viscosity of the slurry will increase by 1, resulting in poor workability and poor surface accuracy of the finished floor surface.

Preferably it is 0.5 parts by weight or less.

A foaming agent is used to prevent foaming from occurring during slurry preparation. If the foamed slurry is spread on the floor surface, it will interfere with the shape of the horizontal surface, and furthermore, the surface will become avatar-like after curing, which is undesirable. Examples of antifoaming agents include silicone-based antifoaming agents and nonionic surfactants, and it has been found that silicone antifoaming agents are particularly good. The amount added is 0.01 to 100 parts by weight of α-type hemihydrate gypsum.
0. The height of the overlapping part is approximately m.

Water, which is a dispersion medium, is a major factor controlling the fluidity of the slurry produced by its stirring, but in the present invention, water/α-type hemihydrate gypsum is used in a weight ratio of 0.27 to 0.40. . At this time, if the ratio of α-type hemihydrate gypsum I to water is lower than this range, it is difficult to expect fluidity.
If it is higher than this range, satisfactory fluidity can be obtained, but solid-liquid separation or insufficient elasticity may occur, which is not preferable.

As mentioned above, considerable fluidity can be obtained by mixing the base material α-type hemihydrate gypsum with a relatively small amount of water and various additives, but if necessary, it is possible to obtain a range that satisfies the fluidity. It is also possible to mix aggregate and the like into the container. Various aggregates can be used in this case, including sand and calcium carbonate.

The above-mentioned various components may be used by being mixed in advance with α-type hemihydrate gypsum, or mixed into water as a dispersion medium.

EXAMPLES The present invention will be described in more detail with reference to Examples below, but the present invention is not limited by these Examples.

Example 1 The materials shown in Table 1 were thoroughly mixed to obtain a slurry. Table 8 shows the flow value of this slurry, the expansion coefficient during curing of the slurry, and the compressive strength after curing.

\ \ 13 - Examples 2 to 5 and Comparative Examples 1 to 2 A slurry was prepared by changing a part of Example 1 as shown in Table 2.

14- Table 8 From the above examples, the method of the present invention improves the flow value to 18 cm or more, maintains a compressive strength of 200 y/d or more, and produces a plaster composition with significantly improved self-smoothness. It is extremely useful. In Table 8, the flow value was measured using the method described above using a pipe with an inner diameter of 5.4α and a height of 9.5 cm. Measurement was carried out using JISAllog on the material that had been brought to an absolutely dry state.

-17 completed-

Claims (1)

[Claims] 0.4 to 4.0 parts by weight of acrylic resin emulsion as resin solid content, 0.2 to 2.0 parts by weight of cement, and 27 to 40 parts by weight of water to 100 parts by weight of α-hemihydrate gypsum. A plaster composition further containing one or more dispersants, dispersion aids, setting regulators, expansion inhibitors, antifoaming agents, water retention agents, aggregates, etc. as required.