JP2748796B2 - Lightweight cement building materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic autoclave-cured lightweight cement building material, and more particularly to an extruded ceramic autoclave-cured lightweight extruded cement building material.

[0002]

2. Description of the Related Art In order to manufacture a lightweight cement product used as a building material, that is, a lightweight cement building material by extrusion molding, a cement as a hydraulic binder is mixed with an aggregate and reinforcing fibers, and also a lightweight aggregate is compounded. This can be performed by passing a material kneaded with water through an extruder.

As this lightweight aggregate, it is common to use inorganic foams such as pearlite and shirasu balloon. However, these inorganic foams are easily broken at the time of kneading or extrusion molding, so that a sufficient weight-reducing effect is exhibited. Not done.

[0004] It has also been proposed to use a thermoplastic resin foam such as expanded polystyrene or expanded vinylidene chloride as a lightweight aggregate (Japanese Patent Publication No. 63-1276, Japanese Patent Publication No. 4-2719).
No. 6). However, in the case of using expanded polystyrene, the expanded polystyrene has a large particle size, so that the expanded polystyrene causes a springback phenomenon after molding and appears on the surface of the material. On the other hand, foamed vinylidene chloride has a small particle size of 100 μm or less after foaming, so a lightweight cement product with good surface skin can be obtained.
Since this foamed vinylidene chloride is expensive, economy is a major problem.

The present inventors have also proposed using a water-absorbing polymer that retains the particle size even after absorbing water as a lightweight aggregate.
(See JP-A-2-133356). In this technology, the water-absorbing polymer that has been absorbed in advance is mixed as an aggregate, and the water in the polymer evaporates due to the heat treatment in the curing and drying steps.
It is based on the idea of creating vacancies. Since the water-absorbing polymer has a smaller particle size than the expanded polystyrene, there is no unevenness on the surface of the product after extrusion molding, and a good surface skin can be obtained. It is also significantly more economical than foamed vinylidene chloride.

[0006] However, the water-absorbing polymer is susceptible to damage by the external force applied in the kneading and extrusion steps, and has problems such as a smaller particle size than the initial particle size or a wide particle size distribution. This distribution of pore size is not particularly problematic in terms of lightness, but exterior materials used in houses or factory buildings are often directly fixed with screws or nails. The size distribution influences.

In order to improve the nailability, it is important to have a gap capable of absorbing the volume increase when the nail enters the material, but the size of the hole has an appropriate range.
In other words, the more nails in a certain particle size range, the better the nailing performance, but in the above case, it is necessary to mix a large amount of a water-absorbing polymer to stably secure the voids, Since a large amount of water is used in association with this large amount of mixing, there is a problem that cement hardenability, which is important in production, is delayed, that is, early strength is low.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an excellent lightweight cement building material which overcomes the disadvantages of the prior art. Further, a specific object of the present invention is to provide a lightweight cement building material having high early strength, which is excellent in nailing properties as well as light in weight, has good surface properties, and is extremely important in the production process.

[0009]

Means for Solving the Problems The inventors of the present invention continued research on lightweight cement building materials mixed with a water-absorbing polymer. The inventors have found that it is effective to use a thermoplastic resin foam having a particle size of 0.2 to 1.5 mm later with a water-absorbing polymer, and have completed the present invention.

Therefore, the gist of the present invention is that 0.2 to 1 part by weight of a water-absorbing polymer and 100% by weight of an inorganic ceramics-based powder composed of a hydraulic binder and an aggregate, and an expansion ratio are 100% by weight.
Autoclaved lightweight with closed cells, comprising 0.1 to 1 part by weight of a thermoplastic resin foam having a particle size of 0.2 to 1.5 mm after foaming of 10 to 50 times, and one or more admixtures. It is a cement building material.

As described above, when only a water-absorbing polymer is used as a weight-reducing material, the nailing property is stabilized, but there is a problem that the setting property of the cement is delayed, and a thermoplastic resin is used as the weight-reducing material. When only a foam is used, there is a problem that a smooth surface cannot be obtained due to unevenness of the foam. In order to solve these problems at the same time, the present invention utilizes a synergistic effect due to the coexistence of both. It is.

[0012]

Next, the reason for limiting the compounding materials and their ratios in the present invention as described above will be described. First, as a preliminary test, the relationship between the amount of the water-absorbing polymer mixed, nailing properties, surface properties of the material, and bending strength after curing for a predetermined time was determined experimentally. These results are shown graphically in FIGS. 1 to 3, and these data were determined as follows.

That is, 50 parts by weight of ordinary Portland cement as a hydraulic binder, 50 parts by weight of silica sand as an aggregate, 5 parts by weight of cellulose fibers as an admixture, and 1 part by weight of a thickener methylcellulose as an admixture, In advance
Extrusion molding by mixing a water-absorbing polymer (eg, Sumikagel manufactured by Sumitomo Chemical) that has been absorbed 30 times by weight, kneading with an appropriate amount of water
(Width 100 mm, thickness 10 mm), steam curing at 50 ° C. × 10 hours, and then autoclaving at 180 ° C. × 6 hours. The material after the steam curing was cut into a specimen having a length of 120 mm, a width of 50 mm, and a thickness of 10 mm, and a bending strength was determined by a centrally concentrated loading method having a span of 100 mm, and was defined as a green strength.

Further, the surface properties of the material after curing in an autoclave were visually observed, and the maximum surface unevenness difference of 0.5 mm or less was evaluated as ○, that of 0.5 mm or more and 1 mm or less as Δ, and that of 1 mm or more was evaluated as x.

Further, the material was cut into 100 mm × 10 mm, and a nail having a diameter of 2.5 mm was directly hit at a position 30 mm × 30 mm from each end face. Was evaluated as Δ, and the others were evaluated as ×.

FIG. 1 shows the raw strength, FIG. 2 shows the surface skin, and FIG. 3 shows the nailing property. From these results, it can be seen that as the amount of the water-absorbing polymer increases, the nailing property becomes better, but on the contrary, the green strength decreases and the surface skin also worsens.

Similarly, expanded polystyrene beads (raw material having a diameter of 0.
(3 to 0.5 mm) are shown in FIGS. 4, 5 and 6, respectively, in relation to the mixing amount and the green strength, surface skin, and nailability. Note that expanded polystyrene beads are 50 times expanded products (particle size
(1.1 to 1.8 mm) and 20-fold foam (particle size: 0.8 to 1.4 mm) were used. The formulation and production conditions are the same as for the water-absorbing polymer.

The material using 50-fold expanded polystyrene beads had a maximum particle size of 1.8 mm at the maximum, and the surface skin was deteriorated by being mixed. Also, it can be seen that the greater the amount of the 20-fold expanded polystyrene bead mixed, the better the nailing performance, but the surface skin is poor and there is no range where both performances are good.

Also, 50 times expanded polystyrene beads were
%, The green strength was low because the moldability was poor and the specific gravity was too small, but the green strength was good under other conditions of the mixing amount.

That is, when foamed polystyrene beads were used, if the particle size after foaming was about 0.8 to 1.4 mm in this experiment, it was found that up to 1 part by weight might not deteriorate the surface skin. . Therefore, 0.5% of the water-absorbing polymer
The same evaluation was carried out by changing the mixing amount of the expanded polystyrene beads by 20 times by weight, and the same evaluation was performed.
The result of FIG. 9 was obtained.

That is, it was found that the surface skin and nailing properties which were not obtained by using the water-absorbing polymer or the expanded polystyrene beads alone were good, and that the conditions were high in green strength.

Therefore, the performance was investigated by changing the amount of each of the expanded polystyrene beads and the water-absorbing polymer in which the original particle size and the expansion ratio were variously varied. As a result, it was found that the inorganic ceramics system composed of a hydraulic binder and an aggregate. For 100 parts by weight of powder,
0.2 to 1 part by weight of water-absorbing polymer and thermoplastic resin foam
It has been found that by adding 1 to 1 part by weight, the synergistic effect of the two can be sufficiently exerted, and a lightweight cement building material having characteristics never before seen can be obtained.

The water-absorbing polymer particles used in the present invention have a water absorption ratio of 20 times even under a strong alkali having a pH of 12 to 13.
(Weight) There is no particular limitation as long as it is granular and maintains the granularity even in the water absorbing state. For example, Sumika Gel (trade name) manufactured by Sumitomo Chemical having a chemical composition of acrylic acid and vinyl alcohol copolymer is suitable.

The mixing amount of the water-absorbing polymer is set to 0.2 to 1 part by weight with respect to 100 parts by weight of the inorganic ceramics powder. When the amount is less than 0.2 part by weight, the effect of reducing the weight is small, and the amount exceeds 1 part by weight. This is because they inhibit the cement hardening reaction.

The particle size of the water-absorbing polymer particles is not particularly limited, but may generally be about 0.1 to 0.5 mm.
The reason why the water absorption ratio is set to 20 times or more is that if the water absorption ratio is less than 20 times, the effect of weight reduction becomes small.

Examples of the thermoplastic resin foam include polystyrene, polyethylene, and acrylic resin, and are not particularly limited in the present invention.
It is preferable that the diameter is 50 times and the particle diameter after foaming is 0.2 to 1.5 mm. The mixing amount is 0.1 to 1 part by weight.

If the expansion ratio is less than 10 times, it is uneconomical because the weight reduction effect is small, and if it exceeds 50 times, it is difficult to obtain a foamed product having a particle size of 1.5 mm or less. Particle size after foaming is 0.2 ~
Although it is 1.5 mm, it is difficult to obtain a foamed thermoplastic resin of less than 0.2 mm, and if it exceeds 1.5 mm, irregularities on the surface of the molded article become large. If the amount is less than 0.1 part by weight, the effect on weight reduction and nailing properties is small, and if it exceeds 1 part by weight, the surface properties deteriorate.

The inorganic ceramics-based powder is composed of a hydraulic binder and an aggregate, and the mixing ratio thereof is not particularly limited. In general, 30 to 50 parts by weight of the hydraulic binder and 70 to 50 parts by weight of the aggregate. The total amount is 100 parts by weight, and the above-mentioned water-absorbing polymer and thermoplastic resin foam are added to it.

As the hydraulic binder, high strength Portland cement, ordinary Portland cement, blast furnace cement and the like are generally used. The aggregate is generally fine powder aggregate such as silica sand powder, fly ash, diatomaceous earth, silica fume, etc., but the type is not limited.

In the present invention, one or more admixtures are blended, and the admixture includes a fiber and a thickener. Such admixtures are generally inorganic ceramic powders
It is sufficient to add 3 to 10 parts by weight with respect to 100 parts by weight, but it may be more or less. One of ordinary skill in the art will be able to determine this as appropriate. Examples of the fibers include carbon fibers, polypropylene fibers, and cellulose fibers. Examples of the thickener include methyl cellulose and ethyl cellulose.

The raw materials thus mixed are extruded after mixing and kneading. Due to the extrusion pressure at that time, phenomena such as partial powderization and drainage of the polymer are observed. However, it was confirmed from the observation of the pore state of the cross section that the polymer damage was significantly reduced as compared with the case of using the polymer alone due to the effect of reducing the extrusion pressure when used in combination with the thermoplastic resin foam. That is, the water-absorbing polymer can exhibit a more stable void-forming effect when used in combination with the thermoplastic resin foam.

After extrusion molding, steam curing is performed at room temperature to 80 ° C., and then autoclave curing is performed. At this time, the autoclave curing may be performed at a temperature of 120 to 180 ° C. as generally performed in order to focus on the curing reaction.

The thus obtained lightweight cement building material according to the present invention is lighter in weight, has excellent nailing properties and surface properties, and is practically the most important in terms of early strength. Show more. Next, the operation and effect of the present invention will be described more specifically with reference to examples.

[0034]

EXAMPLES As a water-absorbing polymer, Sumika Gel S-100 manufactured by Sumitomo Chemical Co., Ltd. (water absorption 30 times by weight, particle size 0.2 mm), expanded polystyrene beads as a thermoplastic resin foam, and further,
Using ordinary Portland cement as hydraulic binder, fine silica sand (particle size about 0.05mm) as aggregate, methylcellulose and cellulose fiber as admixture, respectively
Was determined.

An appropriate amount of water was added thereto, and after mixing and kneading, a flat plate having a width of 100 mm and a thickness of 10 mm was formed using an extruder. This was subjected to steam curing at 50 ° C. × 10H, and the bending strength at that time was determined under the condition of a centrally concentrated loading with a span of 100 mm, and was defined as the green strength. If the green strength exceeds the 30kg / cm ² ○, the 15~30kg / cm ² △, was to evaluate the early strength as × less than 15kg / cm ^2.

After steam curing, autoclaving was performed at 180 ° C. × 6H, and cut into flat plates of 100 mm × 100 mm. 30 mm × 30 from both sides of the flat plate obtained in this way
A nail having a diameter of 2.5 mm was hit at a position of mm, and cracks generated at that time were observed. If no crack is generated,
If cracks did not occur when more than half of the nails were driven, the nailing property was evaluated as x when cracks occurred more than half.

Further, the surface properties, that is, the surface skin, were evaluated as ○ when the maximum unevenness difference on the surface of the flat plate thus obtained was 0.5 mm or less, Δ when it was more than 0.5 mm and 1 mm or less, and × when it exceeded 1 mm. did.

The results are shown in Table 1 together with the mixing ratio.

Examples 1 to 3 all had good performance.

However, in Comparative Example 1, the nailing property was poor because the amount of expanded polystyrene beads was small. In Comparative Example 2, since the amount of expanded polystyrene beads was too large, the green strength was reduced due to a decrease in specific gravity, and the surface skin was poor. In Comparative Example 3, since the expansion ratio of the expanded polystyrene beads was large and the particle diameter after expansion was coarse, the surface skin was poor. In Comparative Example 4, since the blending amount of the water-absorbing polymer was small, the weight reduction was insufficient and the nailing property was poor. In Comparative Example 5, since the blending amount of the water-absorbing polymer was large, the raw strength was insufficient due to the inhibition of curing, and the ideological skin deteriorated.

[0041]

[Table 1]

[0042]

Since the present invention is constituted as described in detail above, it has a water-absorbing polymer which has a water absorption capacity of 20 times or more even under the strong alkali of cement and maintains a granular state in a water-absorbing state. Is 10 to 50 times and the particle size after foaming is 0.2 to 1.5
By using the thermoplastic resin foaming resistance of mm together, there is an effect that a building material having excellent nailing properties and surface texture and having high strength development efficiency in the manufacturing process can be obtained, which is extremely useful in industry.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a mixed amount of a water-absorbing polymer and green strength.

FIG. 2 is a graph showing a relationship between a mixed amount of a water-absorbing polymer and surface skin.

FIG. 3 is a graph showing a relationship between a mixed amount of a water-absorbing polymer and nailability.

FIG. 4 is a graph showing the relationship between the amount of foamed polystyrene beads mixed and green strength.

FIG. 5 is a graph showing the relationship between the amount of foamed polystyrene beads mixed and the surface skin.

FIG. 6 is a graph showing the relationship between the amount of foamed polystyrene beads mixed and nailing properties.

FIG. 7 is a graph showing the relationship between the amount of foamed polystyrene beads and the green strength in a blended system containing 0.5 part by weight of a water-absorbing polymer.

FIG. 8 is a graph showing the relationship between the amount of foamed polystyrene beads and the surface skin in a blended system containing 0.5 part by weight of a water-absorbing polymer.

FIG. 9 is a graph showing the relationship between the amount of foamed polystyrene beads mixed and the nailing performance in a compounding system containing 0.5 part by weight of a water-absorbing polymer.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C04B 111: 30 (72) Inventor Junichi Mizuno 12 Nishiha-cho, Minato-ku, Nagoya-shi Nichiha Co., Ltd. (56) References JP2 -133356 (JP, A) JP 4-27196 (JP, B2) JP-B 63-1276 (JP, B2)

Claims (1)

(57) [Claims] 1. An inorganic ceramics-based powder comprising a hydraulic binder and an aggregate, 100 parts by weight of an inorganic ceramic powder, 0.2 to 1 part by weight of a water-absorbing polymer, an expansion ratio of 10 to 50 times, and a particle size after expansion of 0.2 to 1 part. 1.
An autoclave-cured lightweight cement building material having closed cells, comprising 0.1 to 1 part by weight of a 5 mm thermoplastic resin foam and one or more admixtures.