JPH07110775B2 - Elastic mortar composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mortar composition widely used in the field of civil engineering and construction.

For example, it can be used as paving material for roads, floor material for various factories and parking lots, anti-vibration material for machine foundation, various joint materials and caulking material, and also suitable for repair material and waterproof material. .

[Conventional technology]

A large amount of various mortars and concretes are used in the field of civil engineering and construction. Mortar and concrete have good workability and high strength (particularly compressive strength), but have a drawback that cracks easily occur in the mortar after hardening. It is considered that this is due to the drying and shrinkage of the mortar itself, the temperature change as an external change, freeze-thawing, and the external pressure due to human walking and vehicle passage. In addition, there is a case where the mortar cannot follow the crack when the crack is generated in the base structure.

For this reason, the present inventors have already proposed, as a mortar composition, a system in which a synthetic polymer emulsion having elasticity is added to a combination of cement and aggregate called polymer cement mortar (Japanese Patent Application No. 61-195627). . This system has crack-following properties, has sufficient adhesive strength with the base skeleton, and has good waterproof performance, but the construction thickness is limited to 1 to 2 mm, and cracks occur in mortar when the thickness is 5 mm or more. It is easy and the surface layer of the applied mortar hardens, but when it is 3 to 4 mm or less from the surface layer, an uncured phenomenon occurs.

Therefore, it was not possible to carry out the construction at a place where thickness was required. Further, in recent works, there is a demand for shortening the work process, and a material that can immediately start the next process after the work is desired.

Further, if the hardening phenomenon is slow, there is a problem that the applied material will start to flow out if there is rainfall and flooding half a day after the application.

[Problems to be solved by the invention]

The present invention has been made to solve the above problems, and an object thereof is to provide a mortar composition satisfying all the following requirements.

Must have crack followability Adhesive strength with the base structure should be sufficient Water resistance should be good Wear resistance should be excellent Crack should not occur with deformation function 5mm or more, all layers Curing is sufficient over time. It is an early-strength type and can start the next process within several hours after construction. [Means for Solving Problems] In order to solve the above problems, the present inventors In the cement-based mortar, which is a substance, it was considered necessary to make use of the original performance of the mortar and to provide the mortar with elastic properties. Therefore, the present invention was completed by intensive research.

A mortar composition satisfying this condition is an elastic mortar composition containing a specific synthetic polymer emulsion.

The elastic mortar composition according to the present invention is a mixture of portland cement, ultra-rapid cement, rubber powder and a specific synthetic polymer emulsion with water.

The elastic mortar composition according to the present invention comprises 5 to 40% by weight of Portland cement, 5 to 40% by weight of ultra rapid hardening cement, and rubber powder.
It is desirable to contain 10 to 60% by weight and 5 to 30% by weight of synthetic polymer emulsion (resin solid content), and add water so that the total amount of water is 5 to 40% by weight and knead uniformly. Mix and use.

As the Portland cement, it is possible to use ordinary commercial products such as ordinary Portland cement, early-strength Portland cement, or white Portland cement that are used for industrial purposes.

As ultra-rapid cement, 3CaO ・ SiO ₂ and CaSO ₄ and 11CaO ・ 7Al ₂ O ₃・ CaF ₂ are commercially available under the name of jet cement.
Those containing as a main compound can be used. This cement develops sufficient strength within a few hours by the hydration reaction of 11CaO.7Al ₂ O ₃ .CaF ₂ and CaSO ₄ , so it is mainly used for emergency construction.

As the rubber powder, commercially available natural rubber and crushed synthetic rubber can be used, and in addition, crushed rubber such as used tires, belts, hoses as industrial waste can also be used. .

The size of the rubber powder should be 10 mm or less in maximum diameter, but 5 mm
The following fine powders are more preferable.

The synthetic polymer emulsion used in the present invention is an acrylic polymer emulsion, and is a monomer mixture comprising the following (a) to (d): (a) an alkyl acrylate having an alkyl group having 4 to 8 carbon atoms. Ester 55-90 (wt%) (b) Acrylonitrile and / or styrene 5-40 (wt%) (c) Acrylic acid and / or methacrylic acid 1-10 (wt%) (d) 2-hydroxyethyl acrylate, 2 -Hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, acrylamide, methacrylamide One or more of 1 to 10 (wt%) is a copolymer emulsion obtained by emulsion polymerization using a nonionic emulsifier. .

Examples of the synthetic polymer emulsion include vinyl acetate polymer emulsion, SBR polymer emulsion, ethylene-vinyl acetate polymer emulsion, epoxy resin polymer emulsion, and the like. The object of the present application is achieved for the first time by the above acrylic polymer emulsion without achieving the object of (1).

In addition, an antifoaming agent and a preservative are added as needed. The amount of defoamer added was 0.05 based on the acrylic synthetic polymer emulsion.
~ 0.5% is suitable. Examples of the defoaming agent include Nopco 803
4 (Made by San Nopco), ADEKA NATE B-748 (Made by Asahi Denka)
and so on. The resin solid content of this emulsion is 40-55.
It is about% by weight.

The synthetic polymer emulsion used in the present invention is a copolymer emulsion obtained by emulsion-polymerizing the monomer mixture of (a) to (d) using a nonionic emulsifier as described above. The main reason for using this emulsion is to increase the adhesive strength, adhesive strength and elongation.

55 to 90% of the acrylic acid alkyl ester having an alkyl group having 4 to 8 carbon atoms (C _{4 to} C ₈ ) is used because when the acrylic acid ester having C ₃ or less is used, the elongation of the polymer cement sheet is increased. Is small, the followability of cracks in the base becomes poor, and when an acrylate ester having C ₉ or more is used, the adhesive strength becomes small and the elongation also becomes small.

When the acrylic ester content exceeds 90%, the strength is low, and when it is less than 55%, the elongation is low.

The reason why the amount of acrylonitrile and / or styrene is limited to 5 to 40% is that if the amount is less than 5%, the strength becomes small, and if it exceeds 40%, the elongation becomes small.

The reason for limiting the amount of acrylic acid and / or methacrylic acid to 1 to 10% is that if it is less than 1.0%, both the adhesive strength and the elongation become small, and if it exceeds 10%, the elongation becomes small and the water resistance becomes poor.

The amount of 2-hydroxyethyl acrylate and the like is limited to 1 to 10% because when it is less than 1%, a hair crack is likely to occur, so that water permeability and air permeability are increased and the neutralization prevention performance is deteriorated. This is because if it exceeds 10%, the water resistance becomes poor. Further, when an anionic emulsifier is used in combination, water permeability and air permeability are increased and elongation is reduced.

The composition ratio of the mortar composition is preferably the above-mentioned, and if the portland cement is less than 5% by weight, the long-term strength becomes insufficient, and if it exceeds 40% by weight, the elastic properties decrease.

Further, if the ultra-rapid cement is less than 5% by weight, the initial strength is insufficiently expressed, and if it exceeds 40% by weight, the elastic properties are reduced and the pot life is short.

The more rubber powder is added, the more the elastic properties are improved.
If it exceeds 10% by weight, the strength tends to decrease, and if it is less than 10% by weight, the elastic properties are insufficient. Therefore, this range is preferably 10 to 60% by weight.

When the synthetic polymer emulsion is added in a larger amount, the elastic property is improved, but when it exceeds 30% by weight, the strength is lowered, the water resistance is deteriorated, and when thickened, an uncured phenomenon occurs.

Further, if it is less than 5% by weight, the elastic properties are insufficient.

Further, a suitable amount of water suitable for workability is added so as to be 5 to 40% by weight to adjust the mixing.

Incidentally, 100 parts by weight of the elastic mortar composition described above is added to the fine aggregate 10-2.
It is also possible to use it by adding 00 parts by weight. When the fine aggregate is mixed in the above range, the surface texture becomes smoother than that of the additive-free, and the cost becomes economically low.

The amount to be mixed is preferably 10 to 200 parts by weight, and if it exceeds 200 parts by weight, problems such as strength will occur. As fine aggregates to be used, silica sand Nos. 2, 3, 4, 5 and 6 are generally used.
No.7 and No.7 are used.

It is also possible to use a high performance water reducing material as a substance for improving the fluidity of mortar in this system.

〔Example〕

Examples will be described in order to clarify the effects of the present invention, but the technical scope of the present invention is not limited thereto.

(A) Preparation of Mortar Composition Materials used for preparation of the product of the present invention are as follows.

(A) Portland cement (abbreviated PC) Asano ordinary Portland cement (b) Super fast hardening cement (abbreviated JC) Product name "Jet cement" Onoda Cement Co., Ltd. (c) Rubber powder Waste tires are crushed to a maximum diameter of 5 mm or less (D) Synthetic polymer emulsion (described later) (e) Fine aggregate FM2.7 produced by Kashima Kabushiki Kaisha was tested with the compositions shown in Table 1 to compare the performance of various synthetic polymer emulsions.

The test was also conducted in a system in which water was added to normal sand mortar (PC / fine aggregate = 1/2) (Comparative Example 6). The amount of added water is
50% by weight based on PC.

Further, a system in which 100 parts by weight of fine aggregate was added to 100 parts by weight of the composition shown in Table 1 was also evaluated (Example 3). In this case, the polymer emulsion used was the emulsion (I) described below.

Synthetic polymer emulsion used Acrylic polymer used in the elastic mortar of the present invention
The emulsion (I) whose production method is shown below and
(II) was used. (Examples 1 and 2). Also, a comparative example
As an acrylic polymer emulsion III, IV, V (manufacturing method
Is shown below) and a commercially available SBR type emulsion (abbreviation S
BR) (Product name Petals SB-300 Showa Denko KK product)
And ethylene-vinyl acetate polymer emulsion (abbreviated as EV
A) (Product name Petals EV-300 Showa Denko product)
Used (Comparative Examples 1, 2, 3, 4, 5).

(1) Method of producing acrylic polymer emulsion (I) 137 g of ion-exchange resin treated water (hereinafter simply referred to as ion-exchange water) in one reactor equipped with a stirrer, a cooler and a thermometer
Then, 3 g of sodium pyrophosphate and 4 g of polyoxyethylene lauryl ether (Neugen YX-500 nonionic emulsifier manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) are charged and the internal temperature of the reactor is raised to 80 ° C. Next, 2-ethylhexyl acrylate prepared in advance
A monomer emulsion obtained by emulsifying a monomer mixture of 420 g, acrylonitrile 100 g, 2-hydroxyethyl acrylate 5 g, and methacrylic acid 3 g in a nonionic emulsifier solution prepared by dissolving ionogen YX-500 36 g in ion-exchanged water 282 g 84
Of the 8 g, 80 g is added to the reactor, and subsequently an initiator aqueous solution in which 1 g of ammonium persulfate is dissolved in 5 g of ion-exchanged water is added to perform a pre-reaction. After 10 minutes of pre-reaction, the remaining monomer emulsion is uniformly added over 4 hours while controlling the internal temperature of the reactor to 83 to 85 ° C to carry out emulsion polymerization. Separately from this, an initiator aqueous solution prepared by dissolving 1.2 g of ammonium persulfate in 5 g of ion-exchanged water is uniformly added dropwise from 2 hours after the start of dropping the monomer emulsion to the end of the dropping. After the dropping of the monomer emulsion, the mixture was aged at 83 to 85 ° C. for 1 hour, cooled to room temperature, and 3 g of 23 to 28% ammonia water was added. The obtained acrylic synthetic polymer emulsion had pH = 8.5 and a concentration of 56%.

(2) Manufacturing method of acrylic polymer emulsion (II) In the manufacturing method of acrylic polymer emulsion (I), the monomer mixture liquid consists of 2-ethylhexyl acrylate 330, styrene 190g, 2-hydroxyethyl acrylate 5g, and methacrylic acid 5g. Other than the above, copolymerization was carried out according to the method for producing the acrylic polymer emulsion (I). The pH of the acrylic polymer emulsion was 7.5 and the concentration was 55.2%.

(3) Method for producing acrylic polymer emulsion (III) In the method for producing acrylic polymer emulsion (I),
A polymer emulsion (I) was used except that ethyl acrylate was used instead of 420 g of 2-ethylhexyl acrylate. The obtained acrylic polymer emulsion had a pH of 8.7 and a concentration of 56.1%.

(4) Method for producing acrylic polymer emulsion (IV) In the method for producing acrylic polymer emulsion (I),
2-Hydroxyethyl acrylate and methacrylic acid were removed, and 425 g of 2-ethylhexyl acrylate and 105 g of acrylonitrile were used as a monomer mixture liquid, and the mixture was produced according to the production method of the acrylic polymer emulsion (I).

An emulsion having a pH of 9.5 and a concentration of 55.8% was obtained.

(5) Method for producing acrylic emulsion (V) In the method for producing acrylic polymer emulsion (I),
Inogen YX-500 instead of 4 g charged in the reactor
-500 3 g and 1 g of sodium lauryl sulfonate (made by Emar 10 Kao Soap) are charged, and ingen YX-500 is used as an emulsifier for emulsifying a monomer mixture instead of 36 g of inogen YX-500.
Acrylic polymer emulsion (I) except that a monomer emulsion was prepared using 34 g and 102 g of Emar
Polymerization was carried out according to the production method of. The obtained acrylic polymer emulsion had a pH of 8.7 and a concentration of 56.3%.

(B) Evaluation test Mortar compositions (Examples 1 and 2) using acrylic polymer emulsions (I) and (II), and acrylic polymer emulsions (III), (IV), (V) and SBR An evaluation test was conducted on mortar compositions using EVA (Comparative Examples 1, 2, 3, 4, 5).

Furthermore, the evaluation test was performed on the system (Example 3) to which the fine aggregate was added and the ordinary sand mortar (Comparative Example 6).

(1) Adhesive strength test The test was performed according to JIS A 6909. Mortar was applied on a concrete sidewalk board (JIS A 5304) to a thickness of 8 mm, and the mortar was allowed to stand in a curing room at a temperature of 20 ° C. and a humidity of 65% RH for 4 weeks to measure the adhesive strength.

(2) Water permeability test The test is JIS A 1404 "Testing method for cement waterproofing agent for buildings".
It was carried out in accordance with.

Placing mortar on the mold 40t × 150φm / m, temperature 20 ℃,
The measurement was performed after performing curing for 21 days at a humidity of 65% RH.

The applied water pressure is 3 kg / cm ² , and the pressurization time is 1 hour.

The results are expressed by the increase in water permeability.

Permeability increase = W ₂ -W ₁ W ₁ = the weight before (g) W ₂ = weight immediately Permeability Test embodiment (g) (3) wear resistance test mold 5t × 100φm / m implementing permeability test Placing mortar as a specimen,
Abrasion test was conducted after curing for 28 days at a temperature of 20 ° C and a humidity of 65% RH.

Wear is Taber type, wear wheel is H22, load is 1000g,
The number of cycles is 1000.

The result is expressed by the amount of wear loss.

Amount of wear loss = W ₁ −W ₂ W ₁ = Weight before performing wear test (g) W ₂ = Weight after performing wear test (g) (4) Deformation amount test Physical test method of cement (JIS R 5201 ). The size of the test piece is a prism with a cross section of 40 mm square and a length of 160 mm. After placing this mortar, the temperature is 20 ° C and the humidity is 65%.
After curing for 28 days under RH, it was subjected to measurement.

The distance between the fulcrums was set to 100 mm, and the specimen was loaded at the center of the side surface at a rate of 5 kgf per second, and the displacement of the mortar at maximum load was determined.

As can be seen from the test results in Table 2, those obtained by combining the emulsion (I) or emulsion (II) of the present invention with Portland cement, super rapid hardening cement and rubber powder have high adhesive strength, waterproof performance and resistance. The abrasion test is also good, and it has appropriate elastic properties.

The ones using commercially available SBR and EVA as the emulsion (Comparative Examples 4 and 5) showed relatively good values in the adhesive strength, the water permeability test and the abrasion resistance test, but the deformation which is one of the elastic properties. The amount is small and insufficient for this purpose.

Further, the product of the present invention shows overwhelmingly good results as compared with ordinary sand mortar.

Example 3 is a system in which 100 parts by weight of the fine aggregate is added to 100 parts by weight of the composition shown in Table 2, which is slightly inferior to Examples 1 and 2, but there is no problem in practical use.

The sand mortar of Comparative Example 6 was capable of walking by a person one day after it was cast, while all other compounding systems were capable of walking by a person 3 hours after casting.

(Effects of the Invention) The elastic mortar composition according to the present invention satisfies all of the above-mentioned conditions (1) to (3) and has excellent elastic properties as compared with conventional mortar and polymer cement mortar, so that cracks do not occur, and early strength Since it is a system, the work of the next step can be performed after several hours, and the waterproof performance, the adhesive strength and the abrasion resistance are extremely excellent. Also, it has excellent durability and exhibits its performance over a long period of time.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-52-147626 (JP, A) JP-A-63-55143 (JP, A) JP-A-61-72662 (JP, A) JP-A-54- 43285 (JP, A) JP-A-58-138764 (JP, A)

Claims (1)

[Claims] 1. A mortar composition comprising water mixed in a mixture of Portland cement, ultra-rapid cement, rubber powder and synthetic polymer emulsion, wherein the synthetic polymer emulsion is an acrylic polymer emulsion, Monomer mixture consisting of the following (a) to (d) (a) Acrylic acid alkyl ester having an alkyl group having 4 to 8 carbon atoms 55 to 90 (% by weight) (b) Acrylonitrile and / or styrene 5 to 40 (Wt%) (c) acrylic acid and / or methacrylic acid 1 to 10 (wt%) (d) 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, acrylamide, Emulsifying 1 to 10 (wt%) of methacrylamide with nonionic emulsifier Elastic mortar composition, which is a combined copolymer emulsion.