JPS6355143A - Resilient mortar composition - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to the field of civil engineering and construction, including waterproofing materials for building blocks, repair materials,
This invention relates to a mortar composition used as a concrete frame care material.

[Conventional technology]

In the fields of civil engineering and architecture, mortar compositions are used to decorate and repair surfaces such as inner and outer walls of structures.

As a mortar composition, for example, a system called polymer cement mortar, in which various synthetic polymer emulsions are added to a combination of cement and aggregate, is known. This system has some effects on improving adhesive strength with the base structure, improving waterproof performance, preventing dry-out, and protecting the structure.

However, this conventionally known composition has the disadvantage that cracks tend to form in the mortar after hardening.

This is caused by shrinkage of the mortar itself, by external changes (e.g. temperature changes, freezing and thawing), and by the mortar's inability to follow the crank when cracks occur in the underlying structure. There is. This causes water to enter through the crank, causing water leakage. Additionally, reinforcing bars in concrete are generally stable in alkaline environments without rusting, but the concrete becomes neutral due to the action of carbon dioxide gas in the air, and the reinforcing bars rust due to the action of oxygen, moisture, and carbon dioxide gas. . Furthermore, rusting is promoted by the infiltration of salt. Therefore, it is important to prevent these as much as possible, but if cracks occur, this deterioration will be further accelerated. Conventional polymer cement mortars are insufficient in providing these shielding effects, and when cracks occur in the underlying structure, cracks also occur in the mortar itself, making it unsuitable for this purpose.

[Problem that the invention seeks to solve]

The present invention was made to solve the above problems, and its purpose is to develop a mortar composition as a coating material that satisfies all of the following conditions.

■ Must have crack-following properties ■ Must have sufficient adhesion strength to the underlying structure ■ Must have good waterproof performance ■ Should have low gas permeability as a protection for the building structure, especially to suppress the infiltration of carbon dioxide gas as much as possible [Problems] Means for Solving] In order to solve the above-mentioned problems, the present inventors added elasticity to known polymer cement mortar to prevent the mortar from cranking after hardening and to prevent cracks occurring in the base structure. It is designed to improve waterproof performance and adhesive strength with the underlying structure, and to suppress permeability to gases such as carbon dioxide and oxygen.

In order to satisfy this condition, it is necessary to combine a specific mortar composition with a specific synthetic polymer emulsion.

The elastic mortar used in the present invention contains cement, aggregate, a specific synthetic polymer emulsion, and water as essential components. The elastic mortar composition of the present invention preferably contains 20 to 50% by weight of cement material, 20 to 50% by weight of aggregate, and 15 to 30% by weight of synthetic polymer emulsion (resin solid content). Water is added so that the total amount of water including water in the emulsion is 15 to 30% by weight, and the emulsion is kneaded and mixed uniformly before use.

Examples of synthetic polymer emulsions include vinyl acetate-based polymer emulsions, SBR-based polymer emulsions, ethylene-vinyl acetate-based polymer emulsions, and epoxy resin-based polymer emulsions. Achieving the purpose of the present application for the first time with a system polymer emulsion - The synthetic polymer emulsion used in the present invention is the following (a) to (d):
Monomer mixture (% by weight) (a) Acrylic acid alkyl ester having an alkyl group having 4 to 8 carbon atoms 55 to 90 (0 Acrylonitrile and or styrene 5 to 4 degrees (
c) Acrylic acid and/or methacrylic acid 1-1° (
d) A copolymer emulsion obtained by emulsion polymerization of one or more of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, and methacrylamide 1 to 10 using a nonionic emulsifier, optionally containing an antifoaming agent, Add preservatives. The amount of antifoaming agent added is 0.05 to the acrylic synthetic polymer emulsion.
~0.5% is suitable. Examples of antifoaming agents include Nopco 8034 (-!; manufactured by Nopco), Adekanato B-
748 (manufactured by Asahi Denka). Further, the resin solid content of this emulsion is about 40 to 55% by weight.

In this case, the important things are elongation, strength, which represents elastic properties,
The goal is to balance waterproofness, water resistance, gas permeability, etc. These performances are greatly influenced by the ratio of the synthetic polymer emulsion (resin solid content) to the cement material. That is, when this ratio is high, the elongation increases, the waterproof performance improves, and the gas permeability decreases, but the water resistance is poor and the development of strength is delayed. If this ratio is low, elongation and waterproof performance will decrease, gas permeability will increase, water resistance will improve, and strength will develop quickly.

The most balanced ratio between the two is preferably 50 to 90% by weight.

The aggregate used is generally crushed sand No. 3 or No. 4 because this material is usually used in a thickness of 1 to 5 mm.

No. 5, No. 6, No. 7, etc. are used.

As the cement material, ordinary Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, white Portland cement, etc. can be used, and medium-heat cement, blast furnace cement, alumina cement, and ultra-fast hardening cement can be used.

In addition to the above, the elastic mortar composition of the present invention includes a small amount of finely powdered activated silica, a water repellent, calcium carbonate, and pigments added to the above composition in order to further enhance elastic properties, elongation, strength, aesthetics, etc. The following composition can be used. That is, 20-50% by weight of cement material, 20-50% by weight of aggregate, 0.1-0.5% of finely divided activated silica.
% by weight, water repellent 0.2-0.4% by weight, calcium carbonate 0.1-0.5% by weight, pigment 0.4-1.5% by weight, and synthetic polymer emulsion (resin solid content) 15-15% by weight. It contains 30% by weight and is further mixed with a suitable amount of water as a coating material so that the amount becomes 15 to 35% by weight. Activated silica, water repellent, calcium carbonate are especially waterproof,
Effective in improving workability (ease of application) and water resistance.

As the water repellent, for example, stearate, ammonium oleate, etc. are used.

In addition, as pigments, various mild pigments may be mixed in according to the user's request to obtain the desired color.

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 reasons for using this emulsion are its adhesive strength and
The purpose is to increase adhesive strength and elongation.

Using 55 to 90% of acrylic acid alkyl ester having an alkyl group having 4 to 8 carbon atoms (04 to C8) is 0
When using an acrylic ester of C2 or less, the elongation of the polymer cement sheet is small and the crack followability of the base is poor, and when an acrylic ester of C2 or above is used, the adhesion strength becomes low. This is because the elongation also becomes smaller.

Moreover, when the acrylic acid ester content is 90% or more, the strength is low, and when it is 55% or less, the elongation is low.

Acrylonitrile and/or styrene amount 5-40%
If the strength is less than 5%, it is limited to 40%.
% or more, the elongation becomes small.

The reason why the amount of acrylic acid and/or methacrylic acid is limited to 1 to 10% is because if it is less than 1.0%, both adhesive strength and elongation will be small, and if it is more than 10%, elongation will be small and water resistance will be poor. It is from.

The amount of 2-hydroxyethyl acrylate etc. is 1-10%
The reason for this is that if it is less than 1%, hair cracks are likely to occur, so the water permeability and air permeability are poor, and the carbonation prevention performance is poor, and if it is more than 10%, water resistance is poor. Because it will be. Further, when an anionic emulsifier is used in combination, water permeability and air permeability increase, and elongation decreases.

[Effect]

The elastic mortar composition of the present invention, which is a combination of cement, crushed sand, etc., and a specific synthetic polymer emulsion, is
■It satisfies all of the conditions listed above, has excellent durability, and exhibits its performance over a long period of time.

〔Example〕

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

1. Materials used Table 1 shows the composition of the materials used.

Table 1 Weight% 2. Synthetic polymer emulsions used As acrylic polymers used in the elastic mortar of the present invention (-1:, emulsions ■ and ■ whose manufacturing method is shown below were used. Also, as a comparative example, acrylic polymer emulsion m ,■,v (method g is shown below) and commercially available SBR type emulsion (abbreviated as SBR) and ethylene-
A vinyl acetate polymer emulsion (abbreviated as EVA) was used.

(1) Process for producing acrylic polymer emulsion (1) Ion-exchange resin treated water (hereinafter simply referred to as ion-exchanged water) 137!
J, 3 g of birophosphate, and 4 I of hyphoryoxyethylene lauryl ether (Neuden YX-500 nonionic emulsifier manufactured by Dai-Kogyo Seiyaku Co., Ltd.) and the internal temperature of the reactor was set to 80°C.
The temperature rises to Next, a monomer mixture of 2-ethylhexyl acrylate 4201 acrylonitrile 100i, 5 g of 2-hydroxyethyl acrylate, and 3 g of methacrylic acid was added to 282 g of ion-exchanged water and mixed with Noigun YX-
80I of the monomer emulsion Noyon 848I emulsified in a nonionic emulsifier solution dissolved in 50036# is added into the reactor, and then an aqueous initiator solution in which 1 g of ammonium persulfate is dissolved in ion exchange water 5I is added to perform a pre-reaction. . After 10 minutes of pre-reaction, the remaining monomer emulsion was added uniformly over 4 hours while controlling the internal temperature of the reactor to 83 to 85°C to form an emulsion. Apart from this, ammonium persulfate 1.2! An aqueous initiator solution prepared by dissolving i in ion-exchanged water 5I is uniformly dropped from 2 hours after the start of dropping the monomer emulsion until the end of dropping. After the monomer emulsion dropwise addition was completed, 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 a pH of 8.
．． 5, the concentration was 56%.

(2) Manufacturing method of acrylic polymer emulsion (U) In the manufacturing method of acrylic polymer emulsion (1), the monomer mixture is 2-ethylhexyl acrylate 330. Styrene 19ON, 2-hydroxyethyl acrylate 5
Copolymerization was carried out according to the method for producing acrylic polymer emulsion (1), except that it consisted of g and methacrylic acid 5I.

The acrylic polymer emulsion is 7.5, and the concentration is 5.
It was 5.2%.

(3) Production method of acrylic polymer emulsion (111) In the production method of acrylic polymer emulsion (Rino, 2
-Ethylhexyl acrylate 420. ! Except for the use of ethyl acrylate in step 9, polymer emulsion (
Manufactured using the manufacturing method 1). The obtained acrylic polymer emulsion had a rating of 8.7 and a concentration of 56.1%.

(4) Manufacturing method of acrylic polymer emulsion (IV) In the manufacturing method of acrylic polymer emulsion (1), 2
-Hydroxyethyl acrylate and 2-ethylhexyl acrylate as a monomer mixture excluding methacrylic acid.
It was produced according to the method for producing acrylic polymer emulsion (1) using 1-425 g of acrylonitrile and 105 g of acrylonitrile.

An emulsion with a concentration of 55.8% was obtained.

(5) Manufacturing method of acrylic emulsion (V) In the manufacturing method of acrylic polymer emulsion (I), Noigun YX-5004N is charged into one reactor.
-5003,9 and 1 g of sodium lauryl sulfonate (manufactured by Emarl 1O Kao Soap Co., Ltd.) were added to Noir 7 YX-50036 as an emulsifier for emulsifying the monomer mixture.
1! (Instead of D/I'ly YX-500341
and emal to 2it - [Other than making monomer emulsion, acrylic polymer emulsion (
Polymerization was carried out according to the method described above. The resulting acrylic polymer emulsion had a weight of 8.7% and a concentration of 56.3%.

3. Evaluation test Mortar compositions using acrylic polymer emulsions I and It (Examples 1 and 2) and acrylic polymer Z
ff /l/John III *F/s V + S
Mortar composition using BRe EVA (Comparative Example 1)
, 2, 3, 4°5) were evaluated.

3.-1 Adhesive strength test The test was conducted in accordance with JIS A6909. 2 mortar on concrete sidewalk board (JIS A3304)
kg/m2 and apply this at a temperature of 20℃ and a humidity of 65%RH.
The adhesive strength was measured after being left in a curing room for 4 weeks.

3.-2 Elongation and tensile strength A mold release agent was applied to a smooth iron plate and 2.0 kg/2.0 kg of mortar was applied.
A test specimen was prepared by applying 2 m2 of the resin, peeling it off after curing, and molding it into a sheet.

The test specimen was cured for 28 days in air at a temperature of 20° C. and a humidity of 65% RH before measurements were taken.

This test method was based on JIS A 6008r Synthetic Polymer Roofing Test.

The measurement results of adhesive strength, tensile strength, and elongation are shown in Table 2.

Table 2, Table 3, -3 Water permeability and air permeability test φrrJm A molded board (40tx150) of 1/3 sand mortar coated with 97m2 of mortar on the 2' side was used as a test specimen and cured for 21 days at a temperature of 20°C and a humidity of 65% RH. The measurement was carried out after carrying out.

The water permeability test was conducted in accordance with JIS A1404 r Test method for cement waterproofing agents for construction. The water pressure applied was 3 to 9/
crn2. The pressurization time was 1 hour. The results are expressed in terms of increased water permeability.

Increase in water permeability = w2 - WI Wl - Weight before water permeability test (I) w2 = Weight immediately after water permeability test (,9) Air permeability test is performed at an air pressure of 1 kl
The air permeability coefficient was calculated under the conditions of il/m2.

In addition, the air permeability coefficient in the air permeability test was calculated using the following formula.

Q: Permeated air amount (CC/5ee) L: Thickness of specimen crn) PA: Air pressure equivalent to atmospheric pressure Unit volume weight (kvCC) P: Pressure on both sides of the specimen Force difference (kli+/αs A: Air permeable area (cn12) The results of this test are shown in Table 3.

3,-4 Neutralization acceleration test 1/3 sand mortar molded body (100X100X400mm
) The product of the present invention was applied at a rate of 2 k17/m2 over the entire surface at a temperature of 20°C.

The specimens were subjected to air curing at a humidity of 65% RH for 3 weeks. After curing, test specimens are treated with a neutralization accelerator (@ degree 40
℃, humidity 40% RH, carbon dioxide concentration 10%), and after 3 months, it was taken out and cut, and a phenolphthalein solution was sprinkled on it to measure the depth of carbonation. The results are shown in Table 4.

Table 4 As can be seen from the test results in Tables 2, 3, and 4, the combinations of Emulsion (I) and Emulsion (It) of the present invention with Portland cement aggregate had poor adhesive strength and tensile strength. Since it has high strength and elongation of 135 to 140%, it is considered to have sufficient crack followability.

Furthermore, these materials have low water permeability, low air permeability, and low neutrality depth, so they can be said to be excellent coating materials when judged comprehensively as building body care materials.

The emulsion using commercially available SBR (Comparative Example 4) shows good values in terms of adhesive strength, tensile strength, water permeability, air permeability, and prevention of carbonation, but is insufficient in terms of crack followability. The one using commercially available EVA (Comparative Example 5) shows good values in terms of adhesion and tensile strength, but is insufficient in other respects. Comparative Examples 1.2.3 are also insufficient in elongation, water permeability, and air permeability.

〔Effect of the invention〕

The elastic mortar composition of the present invention has superior elastic properties compared to conventional polymer cement mortar, so it does not generate cracks, has excellent prevention performance, has low gas permeability, and has strong adhesive strength, so it can be used as a waterproofing agent. Excellent as a repair agent and body care agent.

Claims (1)

[Claims] 1. A mortar composition in which water is blended with a mixture of cement material, aggregate, and a synthetic polymer emulsion, wherein the synthetic polymer emulsion is an acrylic polymer emulsion, and the following (a) ) to (d) (a) acrylic acid alkyl ester having an alkyl group having 4 to 8 carbon atoms 55 to 90 (wt%) (b) acrylonitrile and/or styrene 5 to 40
(% by weight) (c) Acrylic acid and/or methacrylic acid 1 to 10 (
(wt%) (d) 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate,
An elastic mortar composition characterized in that it is a copolymer emulsion obtained by emulsion polymerizing 1 to 10 (wt%) of one or more of acrylamide and methacrylamide using a nonionic emulsifier. 2. The elastic mortar composition according to claim 1, wherein the aggregate is silica sand. 3. The elastic mortar composition according to claim 1 or 2, which contains activated silica, a water repellent, calcium carbonate, and a pigment.