JP2001031461A - Antimicrobial cement modifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antimicrobial cement modifier capable of providing a concrete and/or a mortar formulated with a metal ion in comparatively high concentration without inhibiting the hydration reaction of the cement by including an antimicrobial hydrotalcite and a blast furnace slag. SOLUTION: The antimicrobial hydrotalcite is preferably the one of the formula M1-x2+Mx3+(OH-)2+x-y(An-)y/n(M2+ is at least one kind of Mg2+, Fe2+, Ca2+, Zn2+ or Cu2+; M3+ is at least one kind of Al3+ or Fe3+; An- is at least one kind of CO32-, SO42-, Cl-, OH-, NO3- or NO2-; x is a positive number within the range of 0.1<=x<=0.5; y is a positive number within the range of 0.1<=y<=0.5; n is 1 or 2). The blast furnace slag capable of being utilized as the cement admixture has a prescribed standard such as a vitrification degree, a chemical composition and a basicity (CaO+MgO+Al2O3/SiO2), especially preferably the vitrification degree of >=90% and the basicity of >=1.6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement modifier capable of imparting significantly higher antimicrobial properties without inhibiting a hydration reaction of a cement when used in a cement.

[0002] The present invention further relates to a concrete or mortar composition having the above-mentioned cement modifier, which has antimicrobial properties and has excellent durability against sulfuric acid or carbonic acid generated by microorganisms.

[0003]

2. Description of the Related Art Concrete or mortar is indispensable in constituting our present living environment because of its excellent functionality and low cost supported by mass production. However, this concrete or mortar structure, which is generally made permanent, also deteriorates due to various factors, which is often a social problem.

One of the causes of the deterioration of concrete or mortar is the involvement of microorganisms.

Conventionally, as a countermeasure against such deterioration of concrete or mortar caused by microorganisms, the surface of a concrete structure is coated with an organic material having high chemical resistance such as an epoxy resin, a vinyl ester resin or an unsaturated polyester resin. (Concrete Corrosion Protection Guidelines (draft): Sewerage Corporation (1997), JP-A-7-171494), silver, copper, zinc, cement
A method of blending an inorganic metal powder such as nickel (Japanese Patent Application Laid-Open Nos. 4-149053 and 11-79920) has been proposed.

[0006] However, in the former method, defective portions (pinholes, insufficient thickness of the coating) during the application of the organic coating material.
And the latter method is silver,
There are problems that metal powders such as copper are expensive, and that the metal powders are poorly dispersible in a cement composition containing cement and aggregate and cannot exert a sufficient antimicrobial effect.

On the other hand, recently, it has been found that a specific composite metal hydroxide, that is, hydrotalcite, has excellent antimicrobial properties, and the hydrotalcites are used as antibacterial and antifungal agents such as resins, rubbers, fibers and paints. There has been proposed a method for use as an agent (JP-A-6-72816, JP-A-6-65).
011, JP-A-8-48606, JP-A-8-291
011).

[0008]

DISCLOSURE OF THE INVENTION The present inventors have been studying the development of highly durable concrete or mortar with a particular emphasis on the influence of microorganisms. When an antimicrobial material carrying ions is added to the cement, it is difficult to develop sufficient strength as concrete because the inorganic metal ions contained therein inhibit the hydration reaction of the cement, and as a result, it can be expected The problem is that effective microbial properties cannot be imparted. An object of the present invention is to solve such a problem.

That is, the present invention is a method which enables a relatively high concentration of metal ions to be incorporated into concrete / mortar without inhibiting the hydration reaction of cement. It is an object of the present invention to provide a method for imparting a desired effective antimicrobial property to a product.

It is a further object of the present invention to provide a cement modifier which is useful for realizing the above-mentioned method and which is well dispersed in cement and does not adversely affect the physical properties of the obtained concrete / mortar. .

Another object of the present invention is to provide a highly safe cement modification in which heavy metal ions are not eluted from the concrete / mortar structure into the external environment during use in view of environmental safety which has recently been emphasized. To provide materials.

It is a further object of the present invention to exhibit the antimicrobial properties by including the above cement modifier, and to provide a high durability against chemicals such as sulfuric acid or carbonic acid produced by microorganisms. It is to provide a high concrete or mortar composition.

[0013]

Means for Solving the Problems The inventors of the present invention have been diligently studying to solve the above-mentioned problems day and night, and by using a compound supporting inorganic metal ions and a blast furnace slag together, the metal ion Inhibition of the cement hydration reaction can be significantly reduced, so that a large amount of metal ions can be blended without deteriorating the initial strength and physical properties of the concrete / mortar, and as a result, the desired excellent properties of the concrete / mortar found that can impart antimicrobial, further, OH as compounds bearing an inorganic metal ion ^- by using a hydrotalcite having a large amount, it is possible to increase the latent hydraulic blast furnace slag used in combination, denser The ability to prepare concrete / mortar with excellent long-term strength and metal ions in hydrotalcite To be held constant, that the environmental pollution by heavy metals problem does not occur, also thereby antimicrobial be long lasting,
It has been found that by using blast furnace slag, by increasing the chemical resistance of mortar or concrete, durability is improved due to a synergistic effect with antimicrobial properties.

The present invention has been completed based on these various findings.

That is, the present invention is a cement modifier capable of imparting antimicrobial properties to cement, as described in the following items 1 and 2. Item 1. An antimicrobial cement modifier containing antimicrobial hydrotalcite and blast furnace slag. Item 2. The antimicrobial hydrotalcite has the following formula (1):

[0016]

Embedded image M_1-x ²⁺M_x ³⁺(OH^-)_{2 + xy}(A^n-)_{y / n} (1) (where M²⁺Is Mg²⁺, Fe²⁺, Ca²⁺, Zn²⁺Or C
u²⁺At least one of the following:³⁺Is Al³⁺Or Fe³⁺
At least one of the following:^n-Is CO_Three ^2-, SO_Four ^2-, C
l^-, OH^-, NO_Three ^-Or NO_Two ^-At least one of
You. x is 0.1 ≦ x ≦ 0.5, y is 0.1 ≦ y ≦ 0.5
Indicates a positive number. n is 1 or 2. )
Item 4. The antimicrobial cement modifier according to Item 1,

Further, the present invention is a concrete or mortar composition described in the following items 3 and 4. Item 3. An antimicrobial concrete or mortar composition containing antimicrobial hydrotalcite, blast furnace slag, cement and aggregate. Item 4. The antimicrobial hydrotalcite has the following formula (1):

[0018]

Embedded image M_1-x ²⁺M_x ³⁺(OH^-)_{2 + xy}(A^n-)_{y / n} (1) (where M²⁺Is Mg²⁺, Fe²⁺, Ca²⁺, Zn²⁺Or C
u²⁺At least one of the following:³⁺Is Al³⁺Or Fe³⁺
At least one of the following:^n-Is CO_Three ^2-, SO_Four ^2-, C
l^-, OH^-, NO_Three ^-Or NO_Two ^-At least one of
You. x is 0.1 ≦ x ≦ 0.5, y is 0.1 ≦ y ≦ 0.5
Indicates a positive number. n is 1 or 2. )
Item 3. The antimicrobial concrete or concrete according to item 3,
Lutar composition.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The antimicrobial cement modifier of the present invention is characterized by containing at least antimicrobial hydrotalcite and blast furnace slag.

The antimicrobial hydrotalcite used in the present invention is a composite metal hydroxide having antimicrobial properties,
Specifically, it means a composite metal hydroxide having a heavy metal ion such as copper or zinc having an antibacterial property stably inside the crystal structure.

The microorganisms of the present invention include algae, bacteria, fungi including fungi, protozoa, viruses and virus-like substances.
Mention may be made of bacteria, and fungi, including molds. Among them, the genus Thiobacillus, which is a sulfur oxidizing bacterium, is known as a bacterium that produces sulfuric acid and mainly causes deterioration in concrete or mortar in sewerage facilities.Specifically, such bacteria include Thiobacillus thiooxidans, Thiobacillus
us noverus, Thiobacillus verustus and the like. In addition, fungi such as black mold (Aspergillus niger) generated on the surface of building materials that impair the aesthetics of concrete facilities, and algae generated on waterways and impairing the aesthetics are preferably targeted.

As the antimicrobial hydrotalcite used in the present invention, specifically, the following formula (2)

[0023]

Embedded image _{^{Mg 1-x 2+ Al x 3+}} (OH -) 2 + xy (A n-) y / n (2) ( wherein, A ^n-is CO ₃ ^2-, SO ₄ ^2-, Cl ^-, OH ^-, NO
₃ ^- or NO ₂ ^- represents at least one. x is 0.1 ≦ x
≦ 0.5, y indicates a range of 0.1 ≦ y ≦ 0.5. n is 1 or 2. M) of hydrotalcite indicated by)
The same type of substituted complex metal hydroxide obtained by substituting all or a part of g ²⁺ with the same kind of heavy metal ion, for example, Zn ²⁺ or Cu ²⁺ can be exemplified. These heavy metal ions may be used alone or in any combination of two or more.

The isomorphous substituted composite metal hydroxide is Ca
²⁺ and / or Mg ²⁺ and Cu ²⁺ and / or Zn
To an aqueous solution containing ²⁺ , a predetermined amount of an alkaline substance is added, and reacted under stirring to precipitate hydrotalcite crystals. Then, at an alkaline condition of pH 10 or higher, preferably pH 11 or higher, 50 ° C. or higher, It can be produced by a method of heat aging at preferably 80 ° C. or higher for 1 to 10 hours, preferably about 1 to 5 hours.

In the present invention, blast furnace slag generally used as a cement admixture can be widely used. Blast furnace slag which can be generally used as a cement admixture has a vitrification rate, a chemical composition and a basicity (Ca).
O + MgO + Al ₂ O ₃ / SiO ₂ ). In particular, the vitrification rate is preferably 90% or more,
The basicity is preferably 1.6 or more. As the chemical composition is not limited, generally SiO ₂ is about 31 to 40 wt%, CaO about 38 to 45 wt%, MgO is 8
About 2 wt%, Al ₂ O ₃ can be mentioned range of about 13 to 17 wt%. Although not limited, it is preferable that the magnesium oxide content is 10% by weight or less, the sulfur trioxide content is 4% by weight or less, and the chloride ion content is 0.02% by weight or less.

The blast furnace slag is preferably in the form of fine powder obtained by drying and pulverizing granulated blast furnace slag, and its fineness is not particularly limited.
00-10000 cm ² / g, preferably 6000-8
000 cm ² / g.

Specifically, as blast furnace slag fine powder, JI
A material conforming to the standard of SA6206-1997 (blast furnace slag fine powder for concrete) can be suitably used.

The mixing ratio of the antimicrobial hydrotalcite and the blast furnace slag to be mixed in the cement modifier of the present invention is not particularly limited, but is usually 100% by weight of the blast furnace slag.
% Of the antimicrobial hydrotalcite, preferably 15 to 30% by weight.

According to the cement improving material of the present invention, antimicrobial properties can be imparted to concrete or cement mortar prepared from cement by being added to and blended with cement.

That is, the present invention also provides a concrete or mortar composition containing the above cement improving material.

As the cement to which the above cement improving material is applied, any cement other than blast furnace cement in which blast furnace slag has been mixed in advance may be used, and Portland cement can be suitably exemplified.

When the cement of interest is blast-furnace cement, if the antimicrobial hydrotalcite is blended with the blast-furnace slag contained in the blast-furnace cement in the ratio described above, the object of the present invention and The effect can be achieved. The present invention does not exclude such a use method, and it is understood that the present invention is included in the present invention as long as the gist of the present invention of using blast furnace slag and antimicrobial hydrotalcite in combination with cement is used. I do.

The concrete of the cement improving material of the present invention
The mixing ratio in the mortar composition is not limited, but is usually 5 to 50% by weight, preferably 10 to 40% by weight, per 100% by weight of the concrete / mortar composition.

The concrete or mortar composition of the present invention may contain, in addition to the antimicrobial cement modifier of the present invention, commonly used thickeners and water reducing agents as long as the effects of the present invention are not impaired. A cement admixture may be added.

[0035]

EXAMPLES The present invention will be described below with reference to experimental examples and examples.
Although the present invention will be described in detail, the present invention
There is no restriction. The percentages described below are not particularly specified.
Unless otherwise indicated, weight percentages are used.Examples 1-3 Normal Portland cement 364g and Toyoura standard sand 10
40g, blast furnace slag 156g and hydrotalc
(Mg_0.806Cu_0.094Al_0.194(OH)_{2.0 69}(CO
_Three)_0.099Cl_0.115) Were each 52 g (Example 1),
78 g (Example 2), 104 g (Example 3), 0 g (vs.
And the water was added to the mixture at a rate of 338.
g was mixed and kneaded to prepare a concrete composition.
(See Table 1). In addition, the above-mentioned hydrotalcite
Using magnesium, copper chloride and aluminum chloride, M
g²⁺Is 1.875 mol / L, Cu²⁺Is 0.21 mol / L, Al³⁺
And a mixed aqueous solution adjusted to be 0.42 mol / L.
6.25 mol / L sodium hydroxide aqueous solution
Under stirring with water adjusted to pH 11 with sodium
And was prepared by simultaneous dropping. At the time of dropping, the reaction solution
Is maintained at 11 to 12 and the resulting hydrotal
The site crystals were heat-aged in a mother liquor at 60 ° C. for 2 hours to obtain
The crystals obtained are filtered, washed with water and dried to produce
Was.

[0036]

[Table 1]

This was kneaded for 3 minutes using a kneading machine in accordance with the physical test method of cement of old JIS R5201, 10. Strength test. The kneaded material was packed in a steel mold in two steps while stiffening it, and after 5 hours or more, the swelling on the mold was scraped off and left in a moisture box. After a lapse of 24 hours, the test specimen was removed from the mold, completely immersed in water, cured for a predetermined period, and then subjected to the following antimicrobial test and strength test. Experimental Example 1 Antimicrobial test Mortar specimens prepared in Examples 1 to 3 and Control Example (curing period: 24 hours in a moisture box, 13 days in water, length 4c)
mx 4cm x 16cm) with a concrete cutter to a thickness of 3mm, width 4cm x length 4cm x length 3
Specimens for antimicrobial test of mm were prepared (alkaline non-leachable system). In addition, in order to eliminate the effects of the alkali originally present in the mortar during the test, the prepared mortar test specimen was immersed in running water for 4 days, and a test specimen (alkaline leaching system) that leached the alkali was also prepared. did.

Using these, the following antimicrobial test was carried out with reference to JIS Z 2911 "Mold resistance test" and the German test method (DIN) 95256FIL / 95256FAL.

As microorganisms used in the evaluation, bacteria, Escherichia coli (Es
herichia coli JCM 1649), a black mold (Aureobashi dium pulluans F.) detected as a mold from various building materials and determined as a test strain in the JIS mold resistance test.
ERMS-9) was used. Algae are also tested in German test method D.
Green algae (Stichococcus bacillaris NIES) used in IN
-529) was used.

In the antimicrobial test, specifically, a medium for each microorganism was prepared, an agar plate was prepared on a petri dish, and a test mortar specimen was placed thereon. After the mortar specimen was set, a suspension of the microorganism was applied to the entire surface of the petri dish, and the growth state of the microorganism on the mortar specimen and on the agar (around the mortar specimen) was observed (Criterion 1, Reference 2). The results are shown in Tables 2 to 4.

[0041]

[Table 2]

[0042]

[Table 3]

[0043]

[Table 4]

In the tables, the criteria (1) and (2) comply with the criteria described in Tables 5 and 6, respectively.

[0045]

[Table 5]

[0046]

[Table 6]

From the above results, it is found that fungi such as mold and algae are mixed with the cement modifier of the present invention in an amount of 10% by weight or more, and bacteria are added in an amount of 15% by weight.
It can be seen that the above formulation significantly exerts antimicrobial properties. Experimental Example 2 Strength development characteristics of mortar Mortar test specimens prepared according to the method described in the above Examples (Examples 1 to 3, control example: curing period was 7 days and 28 days) according to JISR5201. Then, a bending strength test and a compression strength test were performed.

More specifically, the bending strength test was conducted according to JISR52.
01 "Physical test method of cement" 10. Using a Michaelis double lever-type bending strength tester specified in the strength test, the distance between the fulcrums was 100 mm, and the center of the test piece was 5 kgf / sec (49 N). ) And the maximum load was determined. In addition, the compression strength test is performed in the range of (40 ± 0.1 mm) ² per second using the compression test equipment specified in JISR5201 “Physical test method of cement” 10. It was loaded at a rate of 80 kgf (785 N), and the maximum load was determined. In the test, three specimens were used for each material age. In particular, in the compression strength test, six specimens cut by the bending strength test were used.

As a comparative experiment, only hydrotalcite (not including blast furnace slag fine powder) was used in place of the cement modifier used in the preparation of the mortar specimen at the same ratio as the content in the specimen. A mortar comparative test specimen was prepared by using the comparative test specimen, and a flexural strength test and a compressive strength test were performed on the comparative test specimen in the same manner as described above.

Table 7 shows the results of the bending strength test (the mortar specimen of the present invention (Examples 1 to 3) and the comparative mortar specimen (Comparative Examples 1 to 3)). Are shown in Table 8, respectively.

[0051]

[Table 7]

[0052]

[Table 8]

As can be seen from the above results, hydrotalcite is used in an amount of 4.8 that is an effective antimicrobial property.
%, A decrease in bending strength and compressive strength was observed, but sufficient strength could be maintained by using blast furnace slag in combination. From this, by using hydrotalcite and blast furnace slag together, it is possible to increase the amount of hydrotalcite and mix it while securing the necessary strength as concrete / mortar, and as a result, effective antimicrobial properties It can be seen that can be exhibited.

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Claims (4)

[Claims] 1. An antimicrobial cement modifier containing antimicrobial hydrotalcite and blast furnace slag. 2. An antimicrobial hydrotalcite having the following formula:
(1): embedded image M_1-x ²⁺M_x ³⁺(OH^-)_{2 + xy}(A^n-)_{y / n} (1) (where M²⁺Is Mg²⁺, Fe²⁺, Ca²⁺, Zn²⁺Or C
u²⁺At least one of the following:³⁺Is Al³⁺Or Fe³⁺
At least one of the following:^n-Is CO_Three ^2-, SO_Four ^2-, C
l^-, OH^-, NO_Three ^-Or NO_Two ^-At least one of
You. x is 0.1 ≦ x ≦ 0.5, y is 0.1 ≦ y ≦ 0.5
Indicates a positive number. n is 1 or 2. )
The antimicrobial cement modifier according to claim 1, which is: 3. An antimicrobial concrete or mortar composition comprising antimicrobial hydrotalcite, blast furnace slag, cement and aggregate. 4. An antimicrobial hydrotalcite having the following formula:
(1): embedded image M_1-x ²⁺M_x ³⁺(OH^-)_{2 + xy}(A^n-)_{y / n} (1) (where M²⁺Is Mg²⁺, Fe²⁺, Ca²⁺, Zn²⁺Or C
u²⁺At least one of the following:³⁺Is Al³⁺Or Fe³⁺
At least one of the following:^n-Is CO_Three ^2-, SO_Four ^2-, C
l^-, OH^-, NO_Three ^-Or NO_Two ^-At least one of
You. x is 0.1 ≦ x ≦ 0.5, y is 0.1 ≦ y ≦ 0.5
Indicates a positive number. n is 1 or 2. )
The antimicrobial concrete or claim 3 according to claim 3,
Is a mortar composition.