JPS5814385B2 - Plaster composition with good fluidity - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention enables a free surface to be formed by natural flow by simply pouring a slurry containing a small amount of water as a dispersion medium, and further hardens within a suitable time to ensure excellent surface precision. At the same time, the present invention relates to a fluid plaster composition that has excellent performance in terms of workability, dimensional accuracy, and surface condition of molded products after curing.

In particular, the present invention focuses on the particle size distribution of at least one type of 6-gypsum (hereinafter abbreviated as α-type hemihydrate, etc.) selected from α-type hemihydrate gypsum, β-type hemihydrate gypsum, and ■-type anhydrite, which is used as the main raw material. By controlling the particle size distribution, shape, and specific gravity of the aggregate, the purpose is to be economical and to dramatically improve various performances such as accuracy, dimensional accuracy, fluidity, and surface condition of the cured product.

Although the composition of the present invention can also be used for spray construction or as grout for ground improvement by pumping, these performances are mainly effective in producing cast molded bodies, so below we will focus on these performances to the highest level. The present invention will be explained in more detail with reference to its use as a spreadable floor, which is required to exhibit excellent performance.

Traditionally, to obtain a horizontal surface for the floor of a building, a base is formed with sand scattering or foamed concrete, and mortar is placed on top of it using a sliding ruler or water thread as a reference, but special methods are required to improve the horizontal surface accuracy. Skill is required, and there is also a limit to the area that can be constructed per unit time.

Furthermore, the precision of the mortar bed formed in this way cannot be said to be good.

On the other hand, as a raised floor construction method, floor panels with adjuster bolts are installed, but since this is a point load rather than a surface load on the structural panel itself, the support metal fittings receive concentrated stress, and the horizontal surface remains for a long period of time. is difficult to maintain.

Therefore, a horizontal floor surface with surface loads is required.

Conventionally, it has been known to mix several types of additives into anhydrous plaster or cement materials to increase their fluidity and use them for flooring materials, etc.

For example, West German Patent No. 1943634 describes the use of anhydrite as a flooring material by adding sodium sulfonate of a substance having an amino-S-triazine ring, an alkali metal oxide, an antifoaming agent, etc. ing.

However, this method does not improve the physical properties by adjusting flow rate distribution, aggregate shape, and specific gravity as in the present invention, so it does not provide essential improvements, and economically, the cost of additives is high. It is disadvantageous.

Further, JP-A-47-43118 discloses the use of α-type hemihydrate plaster and an aqueous resin emulsion to obtain a fluid plaster composition.

However, this method is also not economical because it uses an expensive aqueous resin emulsion, and also because the particle size of the α-type hemihydrate gypsum is not specified, cracks tend to occur after hardening.

In addition, it is well known that aggregate not only has an economical effect as a bulking agent, but also has general effects such as reducing weight and developing strength.

For application to flooring materials, for example, Japanese Patent Application Laid-Open No. 49-37426
The publication describes that the base material is hydrated hardening materials such as cements and various types of gypsum, and one or two types of additives such as sand, clay, aggregates such as calcium carbonate, and hardening modifiers.
It has been shown that a horizontal floor surface can be formed by adding 4 or more and distributing the resulting suspension on the floor surface by mixing it with water.

}^Generally, in construction using cement mortar, the same amount or three times the amount of sand as cement is mixed in as aggregate.

However, the aggregate used in these methods does not have a defined particle size distribution, which may reduce the fluidity of the plaster, cause poor surface finish, or cause floating ice on the pouring surface. There are some problems that may occur.

Furthermore, in the construction of cement mortar, it is common to level it with a metal trowel, so little attention is paid to fluidity, and the particle size distribution of sand used as aggregate is not regulated. do not have.

Furthermore, little consideration was given to the shape of the aggregate, such as its sphericity.

Furthermore, in recent years, a construction method in which a heating element is placed in the floor has become widely used, but no attempt has been made to improve the heat transfer performance by using aggregate.

The standard water penetration rate of α-type hemihydrate gypsum is much lower than that of β-type hemihydrate gypsum, so when used as a plaster, the amount of water mixed can be reduced, and the strength of the hardened product is increased.

However, in general, when the amount of mixed water is low, if the mixture is mixed with water and poured onto the floor, it will not have the fluidity to form a horizontal surface due to natural flow.

Therefore, when using gypsum as a horizontal flooring material while taking strength into consideration, special additives are mixed in to increase its fluidity.

On the other hand, looking at the kneading workability of this fluidized plaster with water, if only the base material such as α-type hemihydrate gypsum and various additives such as dispersants are used and no aggregate is mixed, a mixer for kneading etc. In this case, lumps (Tokari 7 mako) may be formed on the kneading instep, and if this is directly spread on the floor surface, it may be difficult to form a horizontal floor surface.

The present inventors previously solved this problem by mixing aggregate with an adjusted particle size distribution with α-type hemihydrate gypsum, etc. with an adjusted particle size distribution, and adding necessary additives/agents to this (particularly Kaisho 53-
110625), but in the present invention, by further selecting the sphericity and specific gravity of the aggregate used, if necessary, the slurry viscosity, we succeeded in providing a gypsum plaster composition with excellent fluidity, high aggregate penetration rate, and high economic efficiency. This is what I did.

That is, the present invention uses a material whose main component is α-type hemihydrate gypsum, etc., whose particle size distribution is adjusted to 60% or more of 0 to 60μ and 40% or less of 0 to 10μ, by weight. The ratio of 0 to 0.15 mm is 20% or less, the particle specific gravity is 1.5 or more and 3.6 or less, and the sphericity of the particles measured by the angle of repose is 45° on a dry basis.
Gypsum: Aggregate = 10025 by weight of the following spherical aggregate
By including it in a ratio of ~100:400, a gypsum plaster with good fluidity can be obtained.

Standard amount of mixed water for gypsum used as a base material in the present invention (JI
(measured according to S-R-9112) is 20 to 70 by weight for α-type hemihydrate gypsum, and 40 for β-type hemihydrate gypsum.
-100 weight scale, and 25 to 80 weight scale for type II anhydrite are mainly used, but from the viewpoint of maintaining strength and shortening drying completion time, it is preferable to mix as little water as possible.

In addition, the particle size distribution is adjusted to a weight ratio of 0 to 60 microns to 60 parts or more, preferably 70 parts or more, and 0 to 10 microns to 40 parts or less, preferably 5 to 35%.

Generally, when the number of particles of 10 μm or less is small, floating ice formation increases during application of the blaster composition, and when the amount exceeds the above range, fluidity becomes poor and strength also decreases.

Furthermore, when the number of particles of 60 μm or less is less than the above range, the fluidity is poor.

However, these are also related to the aggregate particle size as described below.

Particle sizes of 60μ or less were measured using a Shimadzu automatic particle size distribution analyzer RS-50, and ethylene glycol was used as the dispersion medium (the same applies hereinafter).As for the aggregate, various types of aggregate such as river sand and crushed stone sand were used. Examples include sand fly ash, clay, red mud, calcium carbonate slag, and other industrial waste, but sand, fly ash, slag, etc. are common.The particle size distribution of the aggregate is 0.15 mm or less, preferably 15 mm or less. A modified version of candy is used. Furthermore, if particles with extremely large diameters are present, unevenness will occur in the finished bed surface, resulting in poor surface accuracy, so it is natural that a diameter larger than the thickness of the cloth is not allowed.

The aggregate particle size of 0.15 mm was measured using a standard sieve (the same applies hereinafter).

If the amount of fine particles of 0.15 mm or less exceeds the above range, the fluidity of the plaster will be poor and more lumps will be produced during kneading.

When the specific gravity of the aggregate is small, the effective particle size distribution range tends to be biased towards the large particle size side.

A preferred condition is that the specific gravity used is greater than the slurry specific gravity, but this value is 1.5.

The mixing ratio of α-type hemihydrate gypsum etc. and aggregate is 100:
A ratio of 5 to 100:400 is used, but from the viewpoint of impact strength, compressive strength, and fluidity, the ratio is 100:10 to 100:
A range of 300 is particularly useful.

The particle size distribution of α-type hemihydrate gypsum, etc. and aggregate should be considered separately from the viewpoint of maintaining strength and preventing the formation of lumps during cross-tracking, but from the viewpoint of fluidity, it is necessary to consider the particle size distribution of each as a mixture. Should be considered.

That is, if the 0 to 10 μm ratio is not maintained below 40% by weight, the fluidity will be significantly impaired.

Preferably, a range of 5 weight units or more and 35 weight units or less is effective.

In addition, in order to maintain strength, α-type hemihydrate gypsum, etc. of 10 μ or less must be mixed with a particle size of 5 weight percent or more, but if it is less than that, 5 weight percent of 10 to 30 μ, which is a close particle size range, must be mixed. It is necessary to mix the above.

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 liduninsulfonate, β-naphthalenesulfonic acid formaldehyde condensate sodium salt, β-creosote sulfone are used. Typical examples include acids, cresol sulfonic acid condensates, melamine formaldehyde condensate sulfonates and sulfites, polyacrylic dispersants, and phosphate ester surfactants.

These dispersants can be used alone or in combination of two or more, if necessary.

The amount of dispersant added depends on the type of dispersant used, and
The amount varies depending on whether or not more than one type of gypsum is used in combination, but it is usually used in an amount of 0.1 to 10 parts by weight, preferably 0.15 to 5 parts by weight, per 100 parts by weight of α-type hemihydrate gypsum.

If used in an amount exceeding this range, the fluidity may be reduced or the setting and hardening properties may be adversely affected.

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. Ru.

Among the alkali metal sulfates, potassium nitrate and sodium sulfate are selected from the viewpoint of performance and economy.

The amount of alkali metal sulfate added is approximately 0.2 to 3.0 parts by weight per 100 parts by weight of α-type hemihydrate gypsum, etc.

If it is below this range, the expansion suppressing effect will be insufficient, and if it is above this range, setting and hardening properties will be extremely rapid, resulting in a marked drop in workability.

Setting regulators are used to adjust the hardening start time, and for α-type hemihydrate gypsum and β-type hemihydrate gypsum, various slowing agents such as various phosphates, various carboxylic acids, and various proteins are used. be.

In addition, for anhydrous gypsum, Boltland cement is used to shorten the setting time.Water retention agents can cause solid-liquid separation before the slurry spread on the floor begins to gel, or create floating ice. It is used to prevent

Water retention agents include cellulose-based, vinyl-based, acrylic-based, etc., with cellulose-based being widely used.

The amount added varies depending on the type of water retention agent, but is 4.0 parts by weight or less, preferably 1.0 parts by weight or less per 100 parts by weight of α-type hemihydrate gypsum, etc.

However, if this value is expressed more accurately, it can be said to be an amount sufficient to adjust the slurry to a viscosity that provides desirable fluidity in relation to the aggregate particle shape and specific gravity.

This viscosity is 1.5 to 100 poise, preferably 10 to 60 poise.
poise, and its relationship with the above physical properties will be shown by the test examples described below.

Antifreeze agents include calcium chloride, ethylene+I-
/, propylene glycol, etc.

Antifoaming agents include silicone-based and sugar-based ones.
A silicon-based material is preferably used in an effective amount of 0.01 to 2 parts by weight based on α-type hemihydrate gypsum.

Particle sphericity is calculated by dividing the total surface area of the particle group by 2 of the average diameter of all particles.
It is defined as the value divided by the sum of the products, but this is difficult to measure in practice.

Robertson (Nature vol. 152, 53
Page 9 (published in 1943) defines the shape factor as the value obtained by dividing the measured value of the specific surface area by the calculated value of the specific surface area calculated from the equivalent sphere diameter of the particle.

(1,0 in the case of spheres) The inventors believe that when a plaster composition with good fluidity is distributed or sprayed on a flat surface, and considering the physical properties that spread due to self-flowing properties, it is best to evaluate this aggregate using the angle of repose. We found that this meets our purpose.

Therefore, the inventors developed several types of glass spheres, compressed and crushed glass spheres, and several types of glass spheres that were ground using a ball mill.
After passing through a 0.3-inch sieve and sieving the sample so that it passed through a 0.3-inch sieve, the angle of repose of the sieve was measured.

After measuring the angle of repose, when mixed and distributed as a standard plaster cast floor material with the composition shown in Table 1, the fluidity was 2
Now shown in the table.

Fluidity was measured with a flow value of 1, which was determined by an inner diameter of 5.4
cr, a pipe with a height of 9.5 cr is placed on a glass plate, slurry is poured into it, and after 40 seconds the pipe is pulled up to spread the slurry into a circular shape.The radius is measured.The larger this value, the better the fluidity. Approximately 12 as pouring material
12.5Cr to 13c for flooring materials over Cr
It is known from experience that r or more is preferable.

Furthermore, if sand of the same particle size is used in addition to the glass bulbs, the flow value will be 11.8C with 150 parts of aggregate at an angle of repose of approximately 38°.
r, the flow value was found to be 12.7cn at 120 parts of aggregate.

Furthermore, flow values were measured for the mixed weight parts of each type of aggregate using converter slag with a specific gravity of 3.4 (angle of repose 22°) as the aggregate shown in Table 1, and the values shown in Table 3 were obtained.

As a result, the sphericity measured based on the angle of repose is 45°.
Preferably, if it is 300 or less, it can be used as an aggregate without causing floating ice, and if the angle of repose is close to a sphere, the fluidity is preferable even if the aggregate mixing amount is increased considerably to 400 by 100. It has become clear that it can be obtained.

The lower limit of the amount of aggregate to be used relative to the amount of gypsum is not determined by fluidity, but rather by adjusting the weight load, since the weight of the floor per unit area has an important effect on the sound insulation performance in the low frequency sound range, as in the case of floating floors. It is often used, so it was decided from that point of view.

In addition, especially in the case of converter slag, factors for adjusting the heat transfer characteristics were also taken into consideration, and these will be explained in more detail with reference to Examples.

The relationship between plaster viscosity and plaster viscosity is based on the viscosity of slurry that gives a flow value of 120 cr, particle specific gravity,
This was determined by considering the relationship between the angle of repose.

Specifically, granulated artificial aggregate with a particle specific gravity of approximately 1.8, aggregate made by grinding natural rough sea sand for various times in a pole mill (particle specific gravity approximately 2.6), and converter slag with various sphericities ( Particle specific gravity 3.4) with aperture of 2.4 mm and aperture of 0
．． The material was classified using both 15 mm sieves, and the material remaining on the 0.15 mm sieve was used as sample aggregate to produce pouring material having the composition shown in Table 4.

The amount of methylcellulose was changed as appropriate to adjust the flow value to about 12 cm.

The results are shown in Table 5.

As a result, the flow value to provide self-flowing property is 12 cr.
The slurry viscosity to obtain the above changes depending on the aggregate specific gravity and the angle of repose, but the larger the particle specific gravity, the narrower the applicable slurry viscosity range, and the moreover, the sphericity based on the angle of repose is biased towards the low angle of repose region. I understand.

On the other hand, if the particle specific gravity is low and the viscosity is low, the aggregate will float.

For particle specific gravity 1.8, the viscosity range is 169 poise to 58 poise; for particle specific gravity 2.6, the viscosity range is 2 and 7 poise to 52 poise; for particle specific gravity 3.4, the viscosity range is 7.4 poise to 32 poise, respectively. I understand.

When the particle specific gravity is 3.6, the usable range is 100 poise or less.

The reason why there are two viscosities with the same specific gravity and a flow value of approximately 12 CI is that on the high viscosity side, the viscosity naturally regulates the flow value, but on the low viscosity side, particle suspension or sedimentation has a negative effect on fluidity or finish. This is because

The present invention will be explained in more detail with reference to examples below, but these are not intended to limit the invention itself.

Examples 1 to 4 Table 7 shows the physical properties of slurries obtained by adding and mixing the aggregates and water shown in the table to various types of gypsum having the particle size distribution shown in Table 6.

The composition other than gypsum and aggregate at this time is shown in Table 8.

This fluidity is sufficient for use as a gypsum plaster composition.

The slurry of Examples 1 and 2 was poured into a container with an area of 11 m and 13 m.
When it was spread on a concrete slab of m2 in thickness to a thickness of 25 m, it hardened after 4 hours, and the difference in horizontal plane precision was 2.1 mm and 2.9 mm, respectively, which were preferable values.

Example 5 Glass wool with a thickness of 20 m and a density of 96 kg/m' was spread on a concrete slab with a thickness of 120 mr, and a polyethylene waterproof sheet with a thickness of 0.1 um was spread on top of it, and the same as in Example 1 was placed on top of it. A slurry consisting of 100 parts by weight of α-type hemihydrate gypsum, 300 parts by weight of the spherical converter slag of Example 1, 54 parts by weight of water, and the additives shown in Table 8 was spread to a thickness of 30 m.

At this time, the flow value was 14.21 m, and the viscosity was 36 poise.

After one month had passed and sufficient strength had been developed, the sound insulation performance was measured and the results were as shown in Table 9.

It became clear that this resulted in the creation of a highly economical and sufficient sound-insulating floor.

In other words, the fluidity of conventional aggregates with a small angle of repose is low, which limits the amount of aggregate that can be mixed into the plaster composition. However, with the aggregate of the present invention, it was possible to mix aggregate with a high specific gravity at a ratio of 3@ (weight ratio) to plaster, so the thickness of the material could be increased to 30 m. This provides high sound insulation performance.

Example 6 Expanded polystyrene roomm was placed on the slab and O. After laying a polyethylene waterproof sheet of L mm, 20 m of mortar was evenly leveled to form a floor.

On top of this, copper-nickel alloy heating wires covered with butyl rubber and heat-resistant vinyl chloride were laid in a meandering manner at intervals of 10 cr.

30 mm of the slurry used in Example 5 was spread thereon.

On the other hand, as a comparison, 30 mL of a slurry containing no aggregate and 30 nm of 1:3 mortar were poured and cured.

Two weeks later, when a thermosensitive tape was pasted on the surface and electricity was applied, the temperature of the entire surface of the floor of Example 6 was constant at about 18°C, but the difference was about 2°C for the floor excluding aggregate, and the difference for the mortar floor was about 18°C. 3,
A temperature difference of 5C was generated on the floor surface corresponding to the heating wire area and the gap area between the heating lines.

This is because the converter slag, which has good heat conductivity, settles uniformly in the heating wires and the gaps between them, reducing the heat distribution.

As is clear from the above description, the present invention has better fluidity than sand conventionally used with the same particle size.

Furthermore, even in a mortar composition in which a large amount of aggregate is added to gypsum, it exhibits much higher self-flowing properties than sand.

This is because the aggregate itself also has self-flowing properties.

By using this property to fluidize the aggregate and gypsum slurry in two stages, it was possible to obtain even higher fluidity overall.

In addition, in conventional poured flooring materials, when water is added, the amount of mixed water is slightly higher than the control range (although there is a tendency to add a lot of water during work to obtain high fluidity), the aggregate settles. However, when it is deposited on the base, it increases the apparent unevenness of the base, and it also inhibits the self-flow of the gypsum slurry, which is the supernatant liquid, and as a result, it has been experienced that the surface accuracy of the finish deteriorates. Ta.

In particular, when aggregate with low sphericity is deposited, it will stick firmly.
There were many difficulties involved in leveling this with construction leveling tools, and in reality, there was usually nothing that could be done to reach the sedimentary layer beneath the opaque supernatant liquid, gypsum slurry. However, according to the present invention, there is no need to adjust the high fluidity by adjusting the amount of mixed water, so the difficulties associated with the above-mentioned conventional construction methods are avoided.

Furthermore, after 24 hours, the molded article obtained by the present invention after hardening has a compressive strength of 80 kg/Cf for α-type hemihydrate gypsum.
? L or more and bending strength of 30 kY/dm2 or more can be obtained.

In addition, approximately the same value as α-type hemihydrate is obtained for the ■-type anhydrite after about 50 hours.

Claims (1)

[Scope of Claims] 1. At least one type of six plasters selected from α-type hemihydrate plaster, β-type hemihydrate plaster, and ■-type anhydrous plaster has a particle size distribution of 0 to 60μ in weight ratio of 60μ. The particle size distribution of the aggregate is 0.1 in weight ratio to the material whose ratio is 0 to 10μ or less and is adjusted to 40 or less.
Spherical aggregate with a particle size of 5 mm or less is a factor of 20 or less, a particle specific gravity of 1.5 or more and 3.6 or less, and a sphericity of particles measured by the angle of repose of 45 degrees or less on a dry basis. A gypsum composition with good fluidity characterized by containing gypsum and aggregate in a ratio of 100:5 to 100:400. 2 If the particle size distribution of the aggregate used is 0.15 mm or less, 1
5 weight scale or less, 3.4 mm or more is 5 weight scale or less, and the aggregate has (a) particle sphericity measured at the angle of repose of 3
Spherical furnace slag with an angle of repose of 5° or less or (0) A mixture of this furnace slag with other aggregates and a spherical furnace slag with an angle of repose of 35° or less, and the viscosity of the plaster composition is 1.5 poise to 100 poise. The gypsum composition according to claim 1, which contains a dispersant and a water retention agent necessary to maintain the poise.