JPS59164663A - Efflorescence preventer for cement products - 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 an efflorescence inhibitor for cement products.

In the past, it has been nearly impossible to prevent efflorescence in cement products. The efflorescence occurs when soluble components in the hardened cement precipitate on the surface of the hardened cement when water evaporates as the surface dries. Therefore, conventional solutions include reducing the mixing water by using water reducing agents, adding inert substances finer than cement particles, filling capillaries, and adding other oils, fats, and synthetic resins. However, even if these methods reduce efflorescence to some extent, no efflorescence inhibitor has been developed that can completely prevent efflorescence in cement products.

The present inventors have discovered an excellent efflorescence inhibitor that does not cause efflorescence even under adverse conditions where efflorescence is extremely likely to occur, and is completely different from conventional efflorescence inhibitors, and has completed the present invention.

(2) That is, the present invention is based on the general formula (1) (wherein, X is an aliphatic amine having 1 to 7 carbon atoms,
7 cycloalkylamine or a polyamine having 2 to 10 carbon atoms, respectively (residues obtained by removing m+j active hydrogens, A and A' are alkylene groups, and Y is a polycarboxylic acid with two carboxyl groups removed. residue, (nxm+r
rxl is a number from 1 to 10 when X is an aliphatic amine residue or a cycloalkyl amine residue, and a number from 4 to 20 when X is a polyamine residue, and m is a number from 1 to 4. white of a cement product containing an aminocarboxylic acid type compound represented by the number of 0 to 4, 0 is a number of 1 to 4, and M is an ion of hydrogen, alkali metal, alkaline earth metal, or ammonium. It is a bloom inhibitor.

By incorporating the efflorescence inhibitor of the present invention into the interior and/or surface of a cement product using the method described below, the generation of efflorescence from the product can be prevented (3).

1 carbon number as the X residue constituting the general formula (1) of the present invention
Examples of aliphatic amines of ~7 include methylamine, ethylamine, propylamine, isopropylamine, butylamine, pentylamine, hexylamine, 2-ethylbutylamine, dimethylamine, diethylamine, dipropylamine, methylethylamine, methylpropylamine. , methylpentylamine, ethylpropylamine, ethylbutylamine, etc., and examples of cycloalkylamines having 4 to 7 carbon atoms that serve as the X residue include:
Examples include cyclobutylamine, cyclopentylamine, cyclohexylamine, methylcyclohexylamine, and the like. Examples of polyamines having a total carbon number of 2 to 10 include aliphatic polyamines such as ethylene diamine, diethylene triamine, triethylene pentamine, pentaethylene hexazine, piperazine, propylene diamine, and hexamethylene diamine, and aromatic ring polyamines such as xylylene diamine. Examples include polyamines having hexahydroxy (4) lylene diamine, alicyclic polyamines such as isophorone diamine, and aromatic polyamines such as m-phenylene diamine. Among these various amines, aliphatic amines are preferred because they can further improve the efflorescence prevention effect, and aliphatic amines having an alkyl group having 3 to 5 carbon atoms are particularly preferred. If an amine having an alkyl group or a cycloalkyl group having 8 or more carbon atoms is used, not only will the efflorescence prevention effect be reduced, but also air will be entrained in the cement product, resulting in a decrease in strength, which is undesirable.

Examples of the polycarboxylic acid constituting Y in the general formula (1) of the present invention include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, superric acid, azelaic acid, and sebacic acid. Aliphatic saturated dicarboxylic acids, aliphatic unsaturated dicarboxylic acids such as maleic acid and fumaric acid, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, tricarboxylic acids such as tricarballylic acid and benzenetricarboxylic acid, etc. can be used. Among these polycarboxylic acids, saturated and unsaturated dicarboxylic acids having 1 to 4 carbon atoms other than the carboxylic group (5) are preferred from the viewpoint of preventing efflorescence. Examples of these dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, and fumaric acid.
Particularly preferred are succinic acid, maleic acid and fumaric acid.

In the general formula (1) of the present invention, (AO)n or (A
The alkylene oxide constituting O)rr is ethylene oxide, propylene oxide, etc. In addition, in the present invention, the total number of moles of these alkylene oxides (nxm
+yyx#) is a number from 1 to 10 when X is an aliphatic amine residue or a cycloalkyl amine residue. When this number exceeds 10, air is entrained in the cement product, which not only reduces the strength of the product but also reduces the efflorescence prevention effect, which is not preferable. Furthermore, even when X is a polyamine residue (n x m + n'
j! ) is preferably not more than 20, as this will lessen the entrainment of air. In addition, from the viewpoint of efflorescence prevention effect, the molar ratio of ethylene oxide/propylene oxide is 0 to (6
) Coadducts (particularly block-like adducts) within the range of 5 are preferred, and those to which only propylene oxide is added are most preferred. In this case, oxides such as butylene oxide and styrene oxide are co-added to an extent that does not impede the performance of the cement product (in all oxyalkylenes,
(usually 50% by weight or less) is also included within the scope of the present invention. Furthermore, in the general formula (1) of the present invention, (AO square n
The alkylene groups of A1A' represented by , -(A'O''f-go) may be the same or different. When the amine compound has a primary amino group, this amino group is There are cases in which the working alkylene oxide chain is extended by one chain, and cases in which it acts as a divalent and extended by two chains, and either of these cases may be used.

However, from the point of view of the efflorescence prevention effect, compounds that act as divalent amino groups and have alkylene oxide added thereto are preferred, where m in the general formula (1) is 1 and l is 1.
It is a compound of In addition, when the amine compound is a polyamine, the amino group is preferably a residue that acts as a polyvalent and extends many chains7), and in this case too, m is preferably 1 from the viewpoint of preventing efflorescence. preferable.

The method for synthesizing the compound of general formula (1) of the present invention includes adding an alkylene oxide to the amine compound, and then esterifying the polycarboxylic acid using a polycarboxylic acid so that at least one carboxyl group remains free. The method of converting polyalkylene glycol such as polyethylene glycol (molecular weight approximately 200) into polycarboxylic acid compound such as monomethyl succinate is preferable because it is simple and easy, but the method is not limited to this method. There is also a method in which the terminal hydroxyl group is esterified by reaction with an acid, then the terminal hydroxyl group is chlorinated with phosphorus trichloride, this is further reacted with isopropylamine, and then hydrolyzed in the presence of an alkali such as caustic soda. It can also be obtained by adding oxide and then methylating with formic acid and formalin to obtain methyljetanolamine, which is then dehydrated and esterified by adding sodium monomaleate. When these aminocarboxylic acid type compounds (8) are used, the carboxylic acid group is usually used as a salt of an alkali metal such as lithium, sodium, or potassium, an alkaline earth metal such as calcium or magnesium, ammonia, or an organic amine. However, it can also be used in acid form or partially neutralized form. Generally, it is preferable to use the sodium salt.

The cement products treated with the above-mentioned efflorescence inhibitor of the present invention include commonly known mortar or concrete structures, cement 1-secondary products, and cement products treated according to the present invention described below. It also includes.

The cement used here is Portland cement,
Mixed cement, white cement, etc.

To prevent efflorescence in cement products, apply the efflorescence inhibitor of the present invention represented by the general formula (1) above to the inside of the cement product or
This can be achieved by including (adding and/or impregnating) on the surface. There are the following methods for incorporating an efflorescence inhibitor into a cement product.

(9) The first method is to add the above-mentioned efflorescence preventive agent to the cement by 0.2% by weight or more, preferably from 1.0 to 3.0% by weight (inner cutting) when kneading raw materials for cement products. This method involves uniformly dispersing the efflorescence inhibitor of the present invention throughout the cement product.

The second method is to prevent efflorescence according to the present invention by immersing the cement product in the above-mentioned efflorescence inhibitor, applying it with a brush, etc., or spraying it as soon as possible after the cement setting (initial setting) time. This method involves impregnating the surface of cement products with an inhibitor. This second method is preferred over the first method because it achieves the objective with the use of a small amount of anti-efflorescence agent. That is, in the second method, the compound represented by the general formula (1) is usually prepared in an aqueous solution or an aqueous dispersion (concentration is usually 1
0% to 100% by weight) to make cement products
This method involves impregnation. In this case, the amount of the present anti-corrosion agent to be impregnated into the surface of the cement product is generally 20 g/rd or more, preferably 50 g/n1 or more in terms of pure content.

Furthermore, as a third method, a method combining the first method and the second method 10) can be carried out, and this method has an even more effective efflorescence prevention effect than the first or second method. big.

Most efflorescence can be prevented by implementing the first, second, or third method, but if efflorescence occurs slightly due to the passage of time under conditions that are particularly prone to efflorescence, In some cases, it is possible to prevent further progress of efflorescence by repeatedly performing the second method.

As described above, by using the efflorescence inhibitor of the present invention, it is possible to completely prevent efflorescence that precipitates from the surfaces of cement products such as decorative concrete and exposed concrete, and from the joints of tiles and blocks.

The present invention will be explained below with reference to Examples. In addition, in the formulation examples in Examples, parts and % indicate parts by weight and % by weight, respectively.

Example 1 Method ■: (11) Mix 1 part of ordinary Portland cement, 3 parts of sand, and 0.75 parts of water, and further add various efflorescence inhibitors of the present invention shown in Table 1 to the cement. Add 1.0% to 10
A cement mortar prismatic body measuring X 10 X 40 cm was molded, and after being cured in humid air for 24 hours (20° C., R1 190%), the mold was demolded. 2 of these mortar prisms in the long plane direction.
It was cut into cm-wide specimens of 10xlOx2c1n each.

The obtained specimen was immersed 1G in the thickness direction in water at 7°C, and the entire specimen was heated at 7°C, RH 50%, and wind speed 0.2.
The degree of efflorescence generation was visually observed after being left in an environmental container at ~0.3 m/sec, and the results shown in Table 1 were obtained.

Method ■: Mix 1 part of ordinary Portland cement, 3 parts of sand, and 0.75 parts of water, form a 10 x 10 x 40 cm cement mortar prismatic body, and leave it for 24 hours in humid air curing (20
℃, RH 90%), and then molded. This mortar prismatic body was cut into 2cm width pieces in the longitudinal direction, each 1010X10X.
Two specimens were prepared.

(12) Next, various efflorescence inhibitors (50% concentration aqueous solution or aqueous dispersion) of the present invention shown in Table I were applied to the surface of the specimen at a rate of 90 g/rrr as a pure component, and then the method The degree of occurrence of efflorescence was visually observed in the same manner as in (2), and the results shown in Table 1 were obtained.

Method ■: Mix 1 part of ordinary Portland cement, 3 parts of sand, and 0.75 parts of water, and further add 0.7% of the various efflorescence inhibitors of the present invention shown in Table 1 to the cement. te10
Cement 1-mortar prismatic bodies measuring 10 x 40 cm were molded, cured in humid air for 24 hours (20°C, R1 (90%)), and then demolded. , 10×10×2 CI11 specimens were prepared.

These specimens were further added with various efflorescence inhibitors of the present invention (50%
50 g of pure concentrated aqueous solution or aqueous dispersion)
/cd, the degree of efflorescence was visually observed in the same manner as in Method ①, and the results shown in Table 1 were obtained.

The degree of efflorescence was also observed for specimens that did not contain any anti-efflorescence agent or were coated with any anti-efflorescence (13) agent, and the results are also shown in Table 1 as a comparative example.

Table-1 In Table-1, ◎ indicates that no efflorescence is observed even after 4 months, ○ indicates that almost no efflorescence is observed even after 4 months, and Δ indicates that after 4 months ( 14) The mark ``X'' indicates that some efflorescence was observed, and the mark ``X'' indicates that efflorescence was observed significantly after 3 to 4 days.

In addition, -f'Eo)-8, (PO Toro indicates that 8 mol of ethylene oxide and 6 mol of propylene oxide were added to 1 mol of various amines, respectively, -CO-CH=CH
COONa is obtained by semi-esterifying 1 mol of the alkylene oxide adduct with 1 mol of maleic anhydride and then neutralizing it with caustic soda. In addition, the other expressions are the same, and the mark (*) is after adding 3 moles of ethylene oxide to 1 mole of butylamine, and then half-esterifying the block adduct with maleic anhydride by adding 3 moles of propylene oxide. , shows what was neutralized with caustic soda.

Patent applicant: Nippon Cement Co., Ltd. Sanyo Chemical Industries, Ltd. Representative: Patent attorney: Yasuhiro Funakoshi (15)

Claims (1)

[Claims] 1. The following general formula (1) (wherein, X is an aliphatic amine having 1 to 7 carbon atoms,
7 cycloalkylamine, or a residue obtained by removing (m+J) active hydrogens from a polyamine having 2 to 10 carbon atoms, A and A' are alkylene groups, and Y is a polycarboxylic acid with two carboxyl groups removed. residue, (nXm+gox
g is a number from 1 to 10 when X is an aliphatic amine residue or a cycloalkyl amine residue; g is a number from 4 to 20 when X is a polyamine residue; m is a number from 1 to 4. number, l is a number from 0 to 4, 0 is a number from 1 to 4, M is an ion of hydrogen, alkali metal, alkaline earth metal or ammonium). Characteristic efflorescence inhibitor for cement products.