JPS5914416B2 - Composition for mixing cement - Google Patents

Description

Detailed Description of the Invention The present invention relates to an emulsion provided for the modification of mortar and concrete, and more specifically, it improves workability and adhesion to various adherends by incorporating it into mortar and concrete. This article relates to an acrylic emulsion that dramatically improves properties such as flexibility, bending strength, and flexibility.

It is well known that the properties of cement can be improved by blending resin emulsions into cement mortar, concrete, etc. (hereinafter referred to as cement).As resin emulsions, synthetic rubber latex, acrylic emulsions, vinyl acetate emulsions, Ethylene-vinyl acetate emulsions have been used.

Among them, acrylic emulsions are said to be excellent emulsions in overall quantity as resin emulsions for mixing with cement.

For example, vinyl acetate emulsions have drawbacks in terms of water resistance and alkali resistance, and ethylene-vinyl acetate emulsions have considerably improved the drawbacks of vinyl acetate emulsions, but have poor weather resistance and water resistance. It is not as good as acrylic emulsion.

Synthetic rubber latexes such as styrene-butadiene latex or chloroprene latex are also widely used for this purpose, but they have drawbacks in terms of weather resistance and abrasion resistance.

As mentioned above, acrylic emulsions can be said to exhibit the best overall performance as resin emulsions for cement mixing, combined with their excellent weather resistance.

Furthermore, since conventionally commercially available resin emulsions for mixing with cement are anionic, even if they are stabilized by adding a nonionic emulsifier, when mixed with cement, Ca2+ ions in the cement As a result, a uniform cement-resin emulsion was not dispersed, and the performance of the resin emulsion could not be fully exploited.

Furthermore, when a large amount of nonionic emulsifier is used in combination for the purpose of alleviating anionic properties, there are undesirable effects such as a decrease in the water resistance of the resin mortar/concrete and the formation of bubbles due to the tremendous foaming power of the nonionic emulsifier.

Although acrylic emulsions are relatively superior to those using other polymers as long as they are anionic, they cannot avoid the above-mentioned drawbacks.

Therefore, cationic emulsions are said to be suitable for use in cement mixing, and it is true that when cationic resin emulsions are mixed with cement, they can impart unprecedented performance to resin mortar and concrete.

In other words, ■ Ca2+ is well dispersed in cement and aggregate, resulting in an extremely dense structure and particularly improved bending strength.
Good stability, extended pot life, and improved workability ■ Dramatically improved adhesion to various materials.

It has excellent effects such as

Therefore, it can be easily assumed that the best resin mortar/concrete can be made by using a cationic acrylic emulsion for cement mixing.However, contrary to expectations, ordinary Merely cationizing the acrylic emulsion does not bring out the sufficient cationization effect, and the early strength development is insufficient, resulting in poor water resistance at the early stage of curing.

■At the initial stage of cross-talk, it becomes agglomerated, resulting in poor workability.

■Flaws such as insufficient alkali resistance occurred. The present inventors conducted intensive studies to develop a cationic acrylic emulsion for mixing with cement that overcomes the above-mentioned drawbacks. A monomer containing 20 to 99% by weight of one or more selected monomers and 1 to 30% by weight of one or more monomers selected from methyl or ethyl esters of acrylic acid and methacrylic acid. We have discovered that a cationic acrylic emulsion, which is an emulsion polymer of a mixture and has been given cationic properties by a cationic surfactant, exhibits excellent performance, and have completed the present invention based on this finding. .

The mechanism of action of the emulsion on cement according to the present invention is unknown, but polymers that do not contain monomers such as methyl or ethyl esters of acrylic acid and methacrylic acid, which are easily hydrolyzed, have weak early strength development. Also, if the water resistance is insufficient or if the amount is too high, agglomeration and a decrease in alkali resistance are observed when mixed with cement. It is thought that
By hydrolyzing an appropriate amount of the above-mentioned easily hydrolyzable acrylic ester or methacrylic ester, sufficiently controlled Ca crosslinking occurs between the polymers or between the polymer and the hardened cement product, which, together with the effect of cations, results in an excellent cement. It is believed that a polymer-cement composite is formed.

The feature of the present invention is that an appropriate amount of the above-mentioned acrylic ester or methacrylic ester which is easily hydrolyzable is copolymerized with an acrylic acid alkyl ester or methacrylic acid alkyl ester having a carbon number of 4 to 10 alkyl group which is difficult to hydrolyze. As a result, we have fully brought out the excellent weather resistance of acrylic resin and the excellent performance of cationic resin emulsion as a cement admixture.

By mixing the emulsion of the present invention with cement, workability is improved, the solidified material has excellent physical properties, and it exhibits excellent adhesion to various types of structures, achieving unprecedented effects. I can do it.

Details of the effects of the emulsion of the present invention will be described in Examples.

Examples of the acrylic acid alkyl ester or methacrylic acid alkyl ester having an alkyl group having 4 to 10 carbon atoms in the emulsion of the present invention include butyl, isobutyl, 2-
Examples include esters of acrylic acid or methacrylic acid having an alkyl group such as ethylhexyl, n-octyl, and n-hexyl.

Esters having an alkyl group having less than 4 carbon atoms are not preferred in terms of alkali resistance, and esters having an alkyl group having more than 10 carbon atoms are undesirable because cold resistance decreases.

The above-mentioned monomer can be appropriately selected in the range of 20 to 99% by weight of the total monomers, but from the viewpoint of the strength and weather resistance of resin mortar and concrete, it is preferably 30 to 70% by weight, and more preferably 30 to 70% by weight. It is 35 to 55% by weight.

Methyl and ethyl esters of acrylic acid or methacrylic acid are used in the present invention to take advantage of their easy hydrolyzability, but acrylic acid methyl ester is particularly preferred.

The object of the present invention can be achieved by using this in an amount of 1 to 30% by weight based on the total monomers, preferably 1 to 20% by weight, and more preferably 3 to 15% by weight.

If the copolymerization ratio of the easily hydrolyzable acrylic acid ester is too small, the initial effect cannot be obtained, and if it is too large, the alkali resistance will decrease.

In addition to the above two types of monomers, a monomer having an unsaturated ethylene bond that can be copolymerized with them can be used if necessary.

Specifically, styrene, acrylonitrile, vinyl acetate,
Vinylidene chloride, etc., and also includes all other monomers normally used as comonomers in acrylic polymers, but monomers with carboxyl or sulfonic acid groups as functional groups are This is not preferable because it reduces the stability of

However, it is certainly possible to copolymerize a small amount without impairing the stability of the system.

Cationic monomers such as methacryloxyethyltrimethylammonium chloride, dimethylaminoethylmethacrylate hydrochloride, dimethylaminepropylmethacrylamide hydrochloride, dimethyldiarylammonium chloride, and vinylpyridine can also be used.

If the amount of the copolymerizable monomer is too large relative to the total weight, durability will be impaired, so the amount used should be 79 parts by weight or less, preferably 55 parts by weight or less, based on the total weight.

Examples of cationic surfactants that can be used in the present invention include quaternary ammonium compounds such as trimethyloctadecyl ammonium chloride, trimethyldodecyl ammonium chloride, trimethylhexadecyl ammonium chloride, alkyldimethylbenzylammonium chloride, distearyldimethylammonium chloride, and trimethylstearylammonium chloride. salt, or dimethyloctylamine, dimethyldecylamine, dimethyllaurylamine, dimethylmyristylamine, dimethylpalmitylamine, dimethylstearylamine, dimethyloleylamine, trioctylamine, N-methylmorpholine, dimethylbenzylamine, polyoxyethylenealkylamine Among them, quaternary ammonium salts such as trimethylstearylammonium chloride are particularly preferred.

A cationic surfactant can be used alone, but when used in combination with a nonionic surfactant, the stability of the emulsion is improved and there are many positive effects such as improved workability when mixed with cement.

As the nonionic surfactant, any of those normally used in acrylic emulsions can be used.

An example is polyoxyethylene lauryl ether,
Alkyl and alkylphenol ethers of polyoxyethylene such as polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, and polyoxyethylene nonylphenol ether.

Sorbitan fatty acid esters such as sorbitan monostearate, sorbitan monolaurate, sorbitan distearate, sorbitan monooleate, and sorbitan trioleate; polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbicun monolaurate.

These are polyethylene glycol fatty acid ester and chrycerin monofatty acid ester.

Suitable blending amounts of the surfactant are 0.1 to 4% by weight and 0.5% by weight of the cationic surfactant and nonionic surfactant, respectively, based on the solid content of the polymer in the emulsion. ~101
0 parts by weight, more preferably 0.3 to 1.0 parts by weight and 2 to 4 parts by weight, respectively.

The emulsion of the present invention is produced by a conventional polymerization method using a radical initiator, and the cationic surfactant is
It is added before, during, or after polymerization or a combination thereof.

Various additives may be mixed with the emulsion of the present invention as long as the performance as a cement admixture is not deteriorated, but there are cases where new properties can be imparted by adding ordinary cement additives to the emulsion of the present invention. There are many.

Examples of additives that are effective when added to the emulsion of the present invention include film-forming aids such as butylcarpitol, setting accelerators such as calcium chloride, low molecular weight sodium polyacrylate, sodium naphthalenesulfonate, sodium ligninsulfonate, etc. Examples include cement fluidizing agents, silicone-based or ethylene oxide condensation-based antifoaming agents, and ordinary AE agents.

The amount of these ingredients may be the amount adopted in this field.

The mixing ratio of the emulsion of the present invention to cement is:
It is desirable to mix resin solids at a ratio of 1 to 30 parts by weight per 100 parts by weight of cement; if the amount is less than 1 part by weight, the desired effect may not be achieved; If used in excess of this amount, the performance of the cement solidified material will deteriorate.

The emulsion of the present invention is used for plastering, tiling, anticorrosion,
In addition to being usable as an emulsion for ordinary resin mortar for floors, plastering, waterproofing, grafting, etc., it also exhibits excellent performance in spraying applications such as cement ricin.

Next, the composition of the present invention will be described in more detail with reference to Examples and Comparative Examples, and all parts in each example are parts by weight.

Example 1 141.5 parts of ion-exchanged water and 3 parts of lauryldimethylbenzyl ammonium chloride were placed in a stainless steel reaction vessel with an internal volume of 20 A' equipped with a stirrer, and the internal temperature was adjusted to 80°C.
After heating to , a mixture of 50 parts of 2-ethylhexyl acrylate, 10 parts of methyl acrylate, 40 parts of styrene, and 0.5 parts of azobisamidinopropane hydrochloride was continuously added with stirring to carry out a polymerization reaction. The polymerization reaction was photonized after SHr.

Two parts of a silicone antifoaming agent were added and dispersed to this to obtain an emulsion of the present invention.

This emulsion was mixed into mortar and the test shown below was conducted.

1) Preparation of cement mortar Mix 300 parts of river sand with 00 parts of "ordinary Portland cement", add 10 parts of the solid content of the above polymer to the cement, and an appropriate amount of water to obtain a flow value of 180±5 (JISR
5201,9,7 flow test) was obtained.

2) Softness change test After storing the above sample in a curing room (20°C, 65R) () for 90 minutes, the flow value was determined by the method shown in 9.7 flow test of JISR5201, and the softness utilization was determined according to the following formula. .

3) Initial adhesion test According to JISA690755.4 initial adhesion test, mortar paste 2゜kg/Cr1l prepared by the method in section 1)
was applied on a 10 cTL square slate board and heated at 20°C at 65°C.
The test specimen was cured at RH for 3 hours, held at an angle of 45° with respect to the horizontal, and at the center of its surface,
Water with a water head of 150 cIrL is allowed to flow down for 10 minutes from a height of 30 m (30 m/m) through a hole with a diameter of 3 ± 0.1 m/m, and it is observed whether the substrate (slate board) is exposed at the flow down part.

4) Adhesion strength The sample prepared by the method in section 1) was placed on various substrates in a 40x40
Xb After curing at 20°C and 65RH for 28 days, the adhesion strength is measured.

Substrate type: 0 mortar board JISR5201 9.4
■ Glass plate commercially available ■ Aluminum plate commercially available ■ Galvanized iron plate commercially available ■ Hard PVC board commercially available ■ Aroncoat SA coating (acrylic rubber coating manufactured by Toagosei Kagaku Kogyo ■) 5) Water resistance adhesion change rate The material cured for 2 days on the mortar board described in the previous section was soaked in water at 20°C.
After 6 days of immersion, the adhesion strength was measured and the rate of change was determined according to the formula below.

The test results are shown in Table 3, and all of the compositions of the present invention showed good performance.

Examples 2 to 4 Emulsions were produced in the same manner as in Example 1 except for the initial charge and monomer composition, and tests were conducted in the same manner as in Example 1.

The polymerization composition is shown in Table 1.

The results are shown in Table 3, and all showed good performance.

Example 5 Put 82 parts of ion-exchanged water into a 2M stainless steel container equipped with a stirring blade, raise the temperature to 80°C, and then add 50 parts of 2-ethylhexyl acrylate, 10 parts of methyl acrylate, 40 parts of styrene, and polyoxyethylene under stirring. Nonylphenol ether ([(LB17.5) 20 parts dispersion of 50 parts of ion-exchanged water and 10% aqueous solution of azobiscyanoisochracic acid 1
0 parts were continuously added, and the polymerization reaction was completed in 3 hours.

After the reaction was completed, 0.5 part of trimethylstearylammonium chloride was added and dispersed to obtain an emulsion of the present invention.

This was mixed into mortar in the same manner as in Example 1, and a performance test was conducted.

The results are summarized in Table 3 and showed good performance.

Comparative Examples 1 to 3 Emulsions were obtained by the method shown in Example 1 using the following formulations, and the emulsions were mixed into mortar in the same manner as in Example 1, and a performance test was conducted.

The results are summarized in Table 3, and it can be seen that in Comparative Example 1, the initial adhesion performance decreased, in Comparative Example 2, workability and water resistance decreased, and in Comparative Example 3, the adhesive strength to various substrates was insufficient.

The polymerization composition is shown in Table 2.

Claims (1)

[Claims] 1 One or more monomers selected from acrylic acid alkyl esters and methacrylic acid alkyl esters having an alkyl group having 4 to 10 carbon atoms and methyl or ethyl esters of acrylic acid and methacrylic acid. 1. A cement-mixing composition comprising an emulsion polymer of a monomer mixture containing 1 to 30% by weight of one or more monomers, and which is imparted with cationic properties by a cationic surfactant.