JPH0148223B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention relates to the general formula (However, R represents an alkyl group having 1 or more carbon atoms.) A cement slurry and a polyalkylene glycol derivative having a carboxyl group at the terminal, which is an adduct of the polyalkylene glycol represented by the formula and a dibasic acid anhydride. In the presence of an organic solvent that is insoluble in water and capable of forming an inert inverse emulsion, a water-in-oil inverse emulsion is formed, the cement in the inverse emulsion is hardened, and the organic solvent and water are volatilized. This article relates to a method for manufacturing lightweight concrete. [Prior Art] Known methods for reducing the weight of cement concrete include mixing lightweight aggregate into cement slurry and introducing fine air bubbles into cement slurry using a foaming agent. There are two methods using foaming agents: one is to use a surfactant to harden the cement slurry in a foamed state, and the other is to mix aluminum powder into the cement slurry and cause a chemical reaction between the aluminum powder and cement components. A method of foaming is known. In general, the method using a foaming agent has a major drawback in that it is difficult to control the foaming state, resulting in non-uniform foaming. Particularly when producing large molded items, the upper and lower parts
The difference in density was quite large, and the foamed state was generally rough and the appearance was poor. On the other hand, according to the method using lightweight aggregate, relatively uniform molded products can be obtained, but it is difficult to produce lightweight concrete with a specific gravity of 1 or less. [Problems to be Solved by the Invention] The present invention aims to provide a novel method for producing lightweight concrete that improves the above-mentioned drawbacks of conventional lightweight concrete. That is,
The present inventors have discovered that in the presence of the polyalkylene glycol derivative and a cement slurry, a water-insoluble and inert organic solvent forms a water-in-oil inverse emulsion, and this inverse emulsion forms a cement slurry. They discovered that as the hydration reaction progresses, a hard cured product is formed. By drying the cured cement product thus obtained, water and organic solvent are volatilized, and lightweight concrete having a fine foam structure is obtained. [Means for solving the problem] Now, in the present invention, in order to produce an inverse emulsion, a cement slurry is added to a water-insoluble and inert organic solvent in the presence of the polyalkylene glycol derivative. However, if necessary, reinforcing materials, lightweight aggregates,
Fillers and colorants may also be added. The polyalkylene glycol used to prepare the polyalkylene glycol derivative is represented by the general formula above, and has an average molecular weight of, for example, 1,000 to 10,000, preferably 2,000 to 10,000.
5000 polypropylene glycol, polybutylene glycol, etc. are preferred. If the molecular weight of the polyalkylene glycol is lower than 1,000, the ability to form an inverse emulsion will be reduced, and if it exceeds 10,000, the viscosity of the inverse emulsion will become extremely high, making it impractical. The dibasic acid anhydride to be added to the polyalkylene glycol is not particularly limited, and examples thereof include phthalic anhydride, succinic anhydride, maleic anhydride,
Examples include hexahydrophthalic anhydride, but maleic anhydride and succinic anhydride are particularly preferred because addition reactions proceed easily. The polyalkylene glycol derivative has a terminal carboxyl group connected by an ester bond, and this terminal carboxyl group is obtained by mixing a cement slurry with a water-insoluble and inert organic solvent, During the stirring process, the cement is neutralized by metal cations such as Ca ⁺⁺ , Mg ⁺⁺ , Na ⁺ , and K ⁺ released from the cement. The neutralized product of polyalkylene glycol derivatives produced by the above mechanism with metal cations is insoluble in water and has an effective inverse emulsifying effect on inert organic solvents, so it is effective against oils. A water-in-water inverse emulsion is formed. As described above, according to the method of the present invention, there is no need to neutralize the polyalkylene glycol derivative with a basic substance etc. in advance, and the polyalkylene glycol derivative can be used without being neutralized. Therefore, the present invention can be said to be an industrially advantageous manufacturing method. used to produce the inverse emulsion,
Organic solvents that are insoluble in water and capable of forming an inert inverse emulsion include water-insoluble chain solvents that are liquid at room temperature and do not contain hydroxyl groups, aldehyde groups, carbonyl groups, nitro groups, amino groups, or sulfonic acid groups. Examples include cyclic compounds. For example, aliphatic hydrocarbons include pentane, hexane, cyclohexane, heptane, octane, nonane, decane, and the like. Examples of aromatic hydrocarbons include benzene, toluene, xylene, and ethylbenzene, and halides of these may also be used. These organic solvents may be used alone or in combination of two or more. These water-insoluble and inert organic solvents have a boiling point of 20°C or more in order to be vaporized together with water after the cement hardens.
It is desirable that the temperature be around 200℃. Cement used to produce cement slurry includes boltland cement, blast furnace cement, fly ash cement, silica cement, alumina cement, magnesia cement, and the like. Cement slurry is produced by thoroughly mixing cement and water, and the weight ratio of cement and water is preferably about 100:50 to 100:500.
When the water content increases, the weight becomes lighter but the strength decreases, while when it becomes lower, the strength increases but the lightness is lost. The polyalkylene glycol derivative used to produce the inverse emulsion is used in an amount of 1 to 100 parts by weight of a water-insoluble and inert organic solvent.
The amount is preferably about 50 parts by weight, preferably about 3 to 30 parts by weight.
If the amount of the polyalkylene glycol used is too large, the viscosity of the inverse emulsion becomes too high, making it impractical, while if it is too small, a stable inverse emulsion cannot be obtained. The inverse emulsion obtained as described above is poured into a mold and cast, or molded using an extruder or rolling roll, and then cured to harden the cement. ,
It is preferable to use a known cement curing method. During the cement hardening process or after cement has hardened, it is dried to remove the residual moisture from the cement hydration reaction and the organic solvent. The lightweight concrete of the present invention can be produced. In addition, after volatilizing the organic solvent, using an autoclave, high temperature,
High-strength lightweight concrete with a dense foam structure can also be produced by curing at high pressure. In addition, when producing emulsion, aggregates such as crushed stone and sand, lightweight aggregates such as perlite and shirasu balloons, glass fibers, metal fibers, synthetic fibers,
By mixing natural fibers etc., lightweight concrete with various properties can be manufactured. [Operation and Effect] The most important feature of the lightweight concrete obtained by the method of the present invention is that the foamed structure is fine and uniform. Therefore, its appearance is similar to that of ordinary cement concrete, and it has a smooth surface. Furthermore, even if a large molded product is manufactured, there will be no difference in density between the upper and lower parts. this is,
This is because the foam cells are filled with water. The second feature of the present invention is that the specific gravity can be set arbitrarily by changing the amount of water added to cement. That is, as the amount of water mixed with cement increases, the specific gravity of the resulting lightweight concrete decreases, and as the amount of water decreases, the specific gravity increases. A third feature of the present invention is that organic or inorganic reinforcing materials and fillers can be easily mixed into the formed inverse emulsion. This means that the viscosity of the inverse emulsion formed is
This is due to the fact that the reinforcing material and filler are uniformly dispersed. The fourth feature of the present invention is that it has excellent moldability. Since the inverse emulsion obtained by the present invention has a moderate viscosity,
Moldings having various shapes can be produced by casting, or plate-like products can be produced by extrusion molding. A fifth feature of the present invention is that the resulting lightweight concrete is nonflammable. This is a desirable property for fire prevention when used as a building material or the like. The present invention will be specifically explained below using Examples. Example 1 Polypropylene glycol with an average molecular weight of 2000
100 parts by weight of maleic anhydride, 10.4 parts by weight of maleic anhydride, and a small amount of sodium carbonate as a catalyst were charged into a reaction vessel and reacted in a nitrogen stream at 90°C for 3 hours, then gradually cooled. As a result, an addition rate of 91.5% was obtained. A polypropylene glycol maleic anhydride adduct (PPGMA2000) was obtained. Add 100 parts by weight of xylene to 1200 parts by weight of cement slurry obtained by mixing 500 parts by weight of Portland cement with 700 parts by weight of water, and mix well. Add 20 parts by weight of PPGMA 2000 and stir it to form a viscous inverse emulsion. Been formed. When this inverse emulsion was poured into a mold and cured at 60°C and 97% RH for 7 days and removed from the mold, a hard hardened cement product was obtained. By drying this hardened cement product and volatilizing the water and xylene, lightweight concrete with a specific gravity of 0.67 was obtained. The appearance of this lightweight concrete was almost the same as that of ordinary hardened cement. Example 2 100 parts by weight of xylene was added to 1200 parts by weight of a cement slurry obtained by mixing 500 parts by weight of Portland cement with 700 parts by weight of water, and the mixture was thoroughly mixed.
When 20 parts by weight of PPGMA2000 obtained in Example 1 was added and stirred, a viscous inverse emulsion was formed. Add a length of 12 to this inverse emulsion as a reinforcement.
A mixture of 25 parts by weight of alkali-resistant glass chopped strands of mm and 100 parts by weight of pearlite as a lightweight aggregate was poured into a mold, cured at 60°C and 97%RH for 7 days, and removed from the mold. A hard hardened cement product was obtained. It was done. Lightweight concrete was obtained by drying this hardened cement product to volatilize water and xylene.
The specific gravity of this lightweight concrete was 0.64. Example 3 Xylene was added to 1200 parts by weight of cement slurry obtained by mixing 500 parts by weight of Portland cement.
After adding 100 parts by weight and mixing well, 20 parts by weight of PPGMA2000 obtained in Example 1 was added and stirred to form a viscous inverse emulsion. To this inverse emulsion, 10 parts by weight of polypropylene fibers with a length of 12 mm were added as a reinforcing material, and perlite grains were added as a lightweight aggregate.
When 100 parts by weight were mixed, poured into a mold, cured at room temperature for 28 days, and removed from the mold, a hard hardened cement product was obtained. When this hardened cement product was further dried to volatilize water and xylene, lightweight concrete with a specific gravity of 0.62 was obtained. Example 4 100 parts by weight of xylene was added to 1200 parts by weight of cement slurry obtained by mixing 400 parts by weight of Portland cement and 800 parts by weight of water, and after mixing thoroughly,
When 20 parts by weight of PPGMA2000 obtained in Example 1 was added and stirred, a viscous inverse emulsion was formed. Add a length of 12 to this inverse emulsion as a reinforcement.
Add 25 parts by weight of mm alkali-resistant glass chopped strands, mix, pour into a mold, and heat to 97% at 60°C.
After curing at RH for 7 days, a hard cured product was obtained. When this hardened cement product was dried to volatilize water and xylene, lightweight concrete was obtained. The specific gravity of this lightweight concrete was 0.57. Example 5 Lightweight concrete with a specific gravity of 0.59 was obtained in the same manner as in Example 2, except that gasoline was used instead of xylene. Example 6 A lightweight cement having a specific gravity of 0.60 was obtained in the same manner as in Example 2, except that chlorobenzene was used instead of xylene. Example 7 100 parts by weight of xylene was added to 1200 parts by weight of a cement slurry obtained by mixing 600 parts by weight of white Portland cement and 600 parts by weight of water, and the mixture was thoroughly mixed.
When 20 parts by weight of PPGMA2000 obtained in Example 1 was added and stirred, a viscous inverse emulsion was formed. Add a length of 12 to this inverse emulsion as a reinforcement.
Add 25 parts by weight of alkali-resistant glass chopped strands of mm, mix, pour into a mold, heat at 60°C, 97°C.
After curing at %RH for 7 days, a hard cement material was obtained. By drying this hardened cement and volatilizing water and xylene, lightweight concrete with a specific gravity of 0.92 was obtained. Example 8 Polypropylene glycol with an average molecular weight of 3000
When 100 parts by weight of maleic anhydride, 7.2 parts by weight of maleic anhydride, and a small amount of sodium carbonate as a catalyst were charged into a reaction vessel and reacted at 120°C for 3 hours in a nitrogen stream, maleic anhydride was added to polypropylene glycol with an addition rate of 79.2%. (PPGMA3000) was obtained. To 1200 parts by weight of cement slurry obtained by mixing 500 parts by weight of Portland cement with 700 parts by weight of water, 100 parts by weight of toluene was added and mixed well.
When 20 parts by weight of PPGMA3000 was added and stirred, a viscous inverse emulsion was formed. A glass fiber with a length of 1.5 mm is added to this inverse emulsion as a reinforcing material.
When 50 parts by weight and 50 parts by weight of pearlite grains were mixed as a lightweight aggregate and poured into a mold and cured at 60°C and 97% RH for 7 days, a hard hardened cement product was obtained. By drying this hardened cement and volatilizing the water and toluene, lightweight concrete with a specific gravity of 0.77 was obtained. Example 9 A lightweight cement having a specific gravity of 0.75 was obtained in the same manner as in Example except that benzene was used instead of toluene. Table 1 shows the physical properties of the lightweight concrete obtained in the examples. 【table】

Claims (1)

[Claims] 1. General formula (However, R represents an alkyl group having 1 or more carbon atoms.) A polyalkylene glycol derivative having a carboxyl group at the terminal, which is an adduct of the polyalkylene glycol represented by the formula and a dibasic acid anhydride, and a cement slurry. in the presence of an organic solvent that is insoluble in water and capable of forming an inert inverse emulsion to form a water-in-oil inverse emulsion;
A method for producing lightweight concrete, which comprises curing the cement in the inverse emulsion and volatilizing the organic solvent and water.