JPH07115904B2 - Elastic polymer-cement composition having fast setting property - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a) Field of Industrial Application The present invention relates to a polymer cement composition having low-temperature curability, rapid hardening, flexibility and elasticity.

The polymer cement composition of the present invention can be used in various fields such as construction and civil engineering.

(B) Conventional technology It is well known that a synthetic mortar concrete composition having excellent adhesiveness, water resistance, bending strength, etc. can be obtained by mixing synthetic resin emulsion such as ethylene vinyl acetate type, SBR type and acrylic type into Portland cement. is there. It is also known to add an electrolyte such as a sulfuric acid band or quick lime to cement mortar to prevent freezing and improve hardening characteristics at low temperatures.

C) Problems to be Solved by the Invention In a polymer cement composition, it takes a long time to mix a synthetic resin emulsion and to exhibit excellent performance. In addition, blending a sulfuric acid band or quicklime electrolyte into the polymer cement to accelerate the curing speed may destroy the electrical double layer of the Pollimer dispersion, promote dispersion destruction, and cause gel formation or separation. There is.

D) Means for solving the problem When an electrolyte such as a sulfuric acid band or quick lime is added, dispersion breakage of the polymer emulsion is likely to occur, but it is stabilized by arranging a polar group and promoting a crosslinking reaction with the electrolyte. It has been found that the polymer cement paste state is maintained and the curing speed is increased 4 to 5 times faster than the conventional product. Sulfuric acid bands and quick lime are cement admixtures that are relatively easily available and easily handled as general industrial products.

As a result of examining the coagulation effect of the main electrolyte additives with cement, the results shown in Table 1 were obtained.

These results also show that the sulfuric acid band (Al ₂ (SO ₄ ) ₃ ) and quick lime (CaO) have excellent curability. However, these electrolytes are liable to cause dispersion fracture of the polymer dispersion, and the addition concentration is Schulye-Har
According to dyt's law, it becomes like Table-2.

Therefore, the addition amount depends on the electrolyte, but in the sulfuric acid band is 0.1 to 0 per 100 parts by weight of Portland cement.
5 parts by weight, in quicklime, 1 to 3 parts by weight, preferably 1.2 to 2.0 parts by weight. If the amount added is out of the above range, no effect is observed, or dispersion destruction of the polymer dispersion precedes, and gel separation frequently occurs.

In addition, as a polymer dispersion, Tg is considered in consideration of coating strength, flexibility and adhesiveness after film formation in acrylic emulsion with the best durability performance. A range of -25 ° C to + 5 ° C is selected. Low Tg below -25 ℃
If the temperature is above + 5 ° C, it is difficult to obtain the required flexibility. Specifically good that the number of carbon atoms of the alkyl group linked acrylic acid ester is in the range of C ₂ -C _8, which out of this range or strong sticky, sufficient performance or hardness is too high Can not be issued. As long as the object of the present invention is satisfied, styrene other than acrylic acid ester, ethylene, vinyl acetate, etc. may be used for the copolymerization.

Further, the thickener affects the mixing stability and coating workability of the cement polymer mixture, and the optimum addition amount is 0.2 to 0.7 parts by weight, and when it is small, it is not effective, and when it is large, the coating workability becomes difficult. In addition, a water reducing agent is an indispensable additive.
The optimum range is 1 to 0.8 parts by weight. Even if 0.8 parts by weight or more is added, the water reducing effect becomes constant.

E) Action The sulfuric acid band and quicklime electrolyte are metal-crosslinked with the terminal carboxyl groups and methylol groups of the Polmer dispersion,
Interpolymer cross-linking of the polymer is promoted, and the polymerization proceeds.

On the other hand, in cement, the hydration reaction is promoted by the hydration heat of the sulfuric acid band and quicklime, and the generation of cement gel is promoted.
Therefore, the electrolyte, which originally acts as an aggregating gelling agent for polymer dispersions, etc., promotes the cross-linking reaction by introducing a polar group, and also utilizes the fact that heat of hydration is generated, facilitating the cement hydration reaction. It has been found that it has the effect of causing.

F) Effect of the Invention As described above, the present invention utilizes the fact that an electrolyte having a cohesive gelation action is cross-linked with a polar group of an emulsion, without causing cohesive gelation and by heat of hydration to give a cement gel. It has the effect of accelerating the generation rate, and has the effect of imparting quick-hardening properties with the polymer cement mortar having elasticity and flexibility.

G) Example Preparation of sample In the polymer cement mortar having the formulation shown in Tables 3 to 5, a mixture of water and an emulsion was mixed in advance,
Each component other than these was prepared by dry blending, and kneaded according to the preparation of JIS A 6916 cement base conditioning coating material 5.3 sample and used. The values in the table are parts by weight.

Test method-Curing time: A sample is applied to a 4 mm asbestos slate board to a thickness of 2 mm. This is left in a standard condition (20 ° C, 65% RH) and water is flowed down every 30 minutes by the method of JIS A 6909 (1975) 5.3.
The time when the coating film was not washed off was defined as the curing time.

・ Impact resistance: Conforms to JIS A 6916 5.8, but height is 100
It was set to cm, and the presence or absence of cracks, peeling, etc. was observed.

-Water resistance: A sample prepared in the same manner as the measurement of the curing time was aged in a standard state for 7 days and then immersed in water at 20 ° C for 40 days to observe the presence or absence of blistering or peeling.

-Flexibility: Conforms to JIS A 6909 (1984) 5.21. However, the film thickness was 1 mm.

Adhesion: A test piece prepared and cured to have a film thickness of 2 mm according to JIS A 6916 5.6 was cross-cut with a cutter, and the adhesion was measured with cellophane tape.

Low temperature curability: A sample prepared in the same manner as the measurement of curing time
After curing for 24 hours at 5 ° C., the coating film surface was scraped with a nail to check the cured state.

Test results Test results are shown in Table-6.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area C04B 111: 50

Claims (3)

[Claims] 1. A glass transition point (hereinafter referred to as Tg) in the range of -25 ° C. to + 5 ° C. with respect to 100 parts by weight of Portland cement, and 0.1 to 3 in total of N-methylol group and carboxyl group-containing monomer as polar groups. Acrylic ester-based copolymer emulsion having a solid content of 25% by weight
70 parts by weight, 1 to 3 parts by weight of quicklime as a hardening accelerator or 0.1 to 0.5 parts by weight of a sulfuric acid band, and 50 to 300 parts by weight in total of fillers such as aggregate and extender pigment and thickening A rapid-hardening elastic polymer cement composition containing an agent and a water-reducing agent. 2. The addition amount of the thickening agent according to claim 1 is 0.2 per 100 parts by weight of Portland cement.
~ 0.7 parts by weight, a rapid-hardening elastic polymer cement composition. 3. The amount of the water reducing agent added according to claim 1 is 0.1 with respect to 100 parts by weight of Portland cement.
A rapid hardening elastic polymer cement composition, characterized in that it is 0.8 parts by weight.