JP7609602B2 - Hydraulic polymer cement composition and method for application thereof - Google Patents

Description

The present invention relates to a mortar-like hydraulic polymer cement composition that is composed of at least a water-dispersible polyol, a polyisocyanate, an organometallic catalyst, hydraulic cement, and aggregate, and is applied to the surface of a floor base concrete to a depth of 2.5 mm or more and less than 10.0 mm, and a method for applying the composition.

Conventionally, mortar-like hydraulic polymer cement compositions applied to the surface of the floor base concrete have an extremely large shrinkage force of the coating film, so if they are simply applied to the surface of the floor base concrete, they easily peel off. Therefore, as shown in claim 3 of Patent Document 1, it was necessary to first remove the weak layer of the floor base concrete, create grooves 7 to 13 mm deep and 7 to 13 mm wide at the edge of the floor base concrete, and if the distance between opposing grooves exceeds 12 m, create joints 7 to 13 mm deep and 7 to 13 mm wide within 12 m of the grooves, and apply the composition directly to the floor base concrete to a thickness of 6 to 9 mm while filling the grooves and joints.

To solve this problem, Patent Document 2 proposes a composition that can be applied without creating grooves or joints 7 to 13 mm deep and 7 to 13 mm wide in the floor base concrete by blending a specific diluent into the composition to reduce the shrinkage force of the coating film.

Patent Document 3 proposes a hydraulic polymer cement composition that is a mortar-like hydraulic polymer cement composition containing a water-dispersible polyol, a polyisocyanate, cement, aggregate, and water, and is applied to the surface of a concrete substrate to a thickness of 3 mm to 5 mm.

Patent Document 4 also proposes a paste-like hydraulic polymer cement composition that is applied to the surface of floor base concrete to a depth of 0.2 mm or more but less than 4.0 mm, and a method for applying the composition.

JP 2015-81325 A JP 2016-17024 A JP 2017-65942 A JP 2020-37508 A

However, although the composition described in Patent Document 2 can suppress the shrinkage force to a low level, as shown in the examples, even when crude MDI (4,4'-diphenylmethane diisocyanate) is used in the polyisocyanate, which is expected to increase the coating film strength, the compressive strength is only about 21 N/ ^mm2 , which is an issue in that it does not have sufficient performance for use, for example, as floors in food factories, which require higher strength, thermal shock resistance, and impact resistance.

Furthermore, as shown in the examples of the hydraulic polymer cement composition in Patent Document 3, similar to the above, the case where crude MDI (4,4'-diphenylmethane diisocyanate, polymethylpolyphenyl polyisocyanate) is used as the polyisocyanate is shown, and the compressive strength is shown to be 31.0 N/mm2 ^. However, the shrinkage rate of the coating film of this composition is high, and as shown in the evaluation method for thermal shock resistance in paragraph 0036 of Patent Document 3, it is necessary to provide joints 10 mm deep and 10 mm wide 5 mm inward from the ends of the four sides of the test specimen. In other words, if the test specimen does not have such joints, there is a problem that the coating film will easily peel off due to its shrinkage force when evaluating thermal shock resistance.

Furthermore, when polymethyl polyphenyl polyisocyanate is used as the polyisocyanate, the compositions of Patent Documents 2 and 3 have the problem that they turn yellow significantly when exposed to ultraviolet light, and the color of the composition applied to the floor changes, eventually turning brown and damaging the aesthetic appearance.

In addition, the composition of Patent Document 4 has the problem that fine cracks may occur on the coating surface over time.

The problem that the present invention aims to solve is to provide a hydraulic polymer cement composition and its application method, which is a mortar-like hydraulic polymer cement composition that is applied to the surface of a concrete floor base to a thickness of 2.5 mm to 9.0 mm, but has a coating film with low shrinkage stress that will not peel off even when applied directly to the surface of the concrete floor base, and therefore does not require the creation of grooves 7 to 13 mm deep and 7 to 13 mm wide at the edge of the concrete floor base or joints 7 to 13 mm deep and 7 to 13 mm wide every 12 m or less from the grooves, and which has high compressive strength, impact resistance, and thermal shock resistance despite the low shrinkage stress of the coating film, does not change color due to ultraviolet rays, and does not cause fine cracks to appear on the coating film surface over time, resulting in excellent aesthetics.

In order to solve the above problems, the present invention provides a hydraulic polymer cement composition comprising a water-dispersible polyol, a polyisocyanate, an organometallic catalyst, glycerin, a hydraulic cement, and an aggregate,
the water-dispersible polyol contains water, a castor oil-based trifunctional polyol, and a tetrafunctional polyol having a bisphenol A skeleton, has a hydroxyl equivalent of 500 to 800, and is 4 to 10 parts by weight per 100 parts by weight of the total composition;
the castor oil-based trifunctional polyol is more than 30 parts by weight and not more than 50 parts by weight based on 100 parts by weight of the water-dispersible polyol,
The amount of glycerin is more than 0 parts by weight and not more than 5 parts by weight per 100 parts by weight of the total composition,
The polyisocyanate is an aliphatic isocyanurate, and the polyisocyanate is 5 to 15 parts by weight per 100 parts by weight of the total composition;
The hydraulic cement is 5 to 15 parts by weight based on 100 parts by weight of the total composition.
The aggregate is 70 to 85 parts by weight per 100 parts by weight of the total composition.
The present invention provides a hydraulic polymer cement composition comprising:

The invention described in claim 2 provides a hydraulic polymer cement composition according to claim 1 or claim 2, characterized in that the polyisocyanate is hexamethylene diisocyanurate.

The invention described in claim 3 provides a method for applying the hydraulic polymer cement composition described in claim 1 or 2 to a floor base concrete surface to a thickness of 2.5 to 10 mm.

The hydraulic polymer cement composition of the present invention has the effect of being able to be applied to the surface of floor base concrete to a thickness of 2.5 mm to 9 mm, and also has the effect of causing extremely small shrinkage stress, which is the stress generated inside the hardened coating film. Therefore, even if the above thickness is applied directly onto the floor base concrete, the hardened coating film will not peel off.

In addition, because the hydraulic polymer cement composition of the present invention has an extremely small coating shrinkage stress as described above, there is no need to provide joints 7 to 13 mm deep and 7 to 13 mm wide at the edges of the floor base concrete or every 12 m or less on the floor base concrete surface, as was previously required. This means that the composition can be applied to the floor base concrete surface easily and in a short time, resulting in low cost.

In addition, the hydraulic polymer cement composition of the present invention has the effect of having sufficient compressive strength, impact resistance, and thermal shock resistance, even though the shrinkage stress, which is the stress generated inside the coating film, is extremely small. Of course, the hydraulic polymer cement composition of the present invention can be used even if the special characteristic of thermal shock resistance is not required.

In addition, since the polyisocyanate in the hydraulic polymer cement composition of the present invention is composed of an aliphatic isocyanurate, the coating film after curing does not yellow due to sunlight or ultraviolet rays, etc., and has an excellent appearance.

The hydraulic polymer cement composition of the present invention has good application workability even when applied to a thickness of 2.5 to 5 mm, which is slightly thinner than conventional compositions, and has sufficient thermal shock resistance to prevent peeling or cracking even when washed with hot water, as is done on food factory floors.

Furthermore, the hydraulic polymer cement composition of the present invention has the effect that after it is applied to the surface of a floor base concrete and hardens, there is almost no occurrence of fine cracks on the coating surface over time.

This is a model diagram of coating film peeling, viewed from the cross-sectional direction of the coating film, showing the state in which the coating film of a coating floor material applied to the surface of a base concrete material peels off at an angle of 5 degrees due to the coating film shrinkage force T. FIG. 1 is a graph showing the relationship between the surface tensile strength and the residual laitance rate of a base concrete having a water-cement ratio of 60%.

The present invention will be described in detail below.

The hydraulic polymer cement composition of the present invention, in regard to the hydraulic polymer cement composition of claim 1, is a hydraulic polymer cement composition comprising a water-dispersible polyol, a polyisocyanate, an organometallic catalyst, glycerin, hydraulic cement, and an aggregate, in which the water-dispersible polyol contains water, a castor oil-based trifunctional polyol, and a tetrafunctional polyol having a bisphenol A skeleton, the hydroxyl equivalent is 500 to 800 and is 4 to 10 parts by weight per 100 parts by weight of the entire composition, and the castor oil-based trifunctional polyol is 3 to 4 parts by weight per 100 parts by weight of the water-dispersible polyol. The hydraulic polymer cement composition is characterized in that the amount of glycerin is more than 0 parts by weight and not more than 50 parts by weight, the amount of glycerin is more than 0 parts by weight and not more than 5 parts by weight per 100 parts by weight of the entire composition, the polyisocyanate is composed of an aliphatic isocyanurate, the amount of polyisocyanate is 5 to 15 parts by weight per 100 parts by weight of the entire composition, the amount of hydraulic cement is 5 to 15 parts by weight per 100 parts by weight of the entire composition, and the amount of aggregate is 70 to 85 parts by weight per 100 parts by weight of the entire composition, and in addition to these, additives such as pigments, dispersants, defoamers, and diluents can be blended as necessary.

The water-dispersible polyol used in the present invention contains water, a castor oil-based trifunctional polyol, and a tetrafunctional polyol having a bisphenol A skeleton, and the castor oil-based trifunctional polyol is castor oil and its derivatives, such as diglycerides and monoglycerides of castor oil fatty acids and mixtures thereof, and is a polyol with three hydroxyl groups. The hydroxyl equivalent of the castor oil -based trifunctional polyol used in the present invention is preferably 250 to 450. If it is less than 250, the shrinkage stress of the cured product increases, causing the coating film to peel off from the base concrete, or the curing speed increases, resulting in poor workability, and if it exceeds 450, the strength after curing as a hydraulic polymer cement composition is insufficient. The content of the castor oil-based trifunctional polyol in the water-dispersible polyol is preferably more than 30 parts by weight and not more than 50 parts by weight in 100 parts by weight of the water-dispersible polyol, and if it is 30 parts by weight or less, the compressive strength may be insufficient, and if it exceeds 50 parts by weight, the thermal shock resistance may be insufficient.

The tetrafunctional polyol having a bisphenol A skeleton is an epoxy ring-opening polyol obtained by reacting a polyepoxy compound having a bisphenol A skeleton with an active hydrogen compound, and the hydroxyl equivalent is preferably 250 to 450. If the hydroxyl equivalent is less than 250, the shrinkage stress of the cured product increases, causing the coating film to peel off from the base concrete, or the curing speed increases, resulting in poor workability, and if it exceeds 450, the strength after curing as a hydraulic polymer cement composition is insufficient. The content of the tetrafunctional polyol having a bisphenol A skeleton in the water-dispersible polyol is preferably more than 2 parts by weight and not more than 15 parts by weight per 100 parts by weight of the water-dispersible polyol. If it is 2 parts by weight or less, the compressive strength may be insufficient, and if it exceeds 15 parts by weight, the thermal shock resistance may be insufficient.

The hydroxyl equivalent of the water-dispersible polyol used in the present invention is preferably 500 to 800. If it is less than 500, the hydraulic polymer cement composition will harden too quickly, resulting in poor workability, and if it exceeds 800, the hydraulic polymer cement composition will have insufficient strength after hardening. The amount of water-dispersible polyol blended is preferably 4 to 10 parts by weight per 100 parts by weight of the total composition. If it is less than 4 parts by weight, the strength of the hardened composition will decrease, and if it exceeds 10 parts by weight, the workability when applying the composition with a metal trowel will decrease.

The amount of glycerin used in the present invention is more than 0 parts by weight and not more than 5 parts by weight per 100 parts by weight of the total composition, and is an amount that restores the compressive strength, impact resistance, and thermal shock resistance that become insufficient due to the addition of the tetrafunctional polyol having a bisphenol A skeleton.

The polyisocyanate used in the present invention is obtained from an aliphatic polyisocyanate and is composed of an aliphatic isocyanurate having an isocyanurate structure. In particular, hexamethylene diisocyanurate obtained by cyclotrimerizing 1,6-hexamethylene diisocyanate is preferred because it has excellent weather resistance and improves the hardness of the coating film. To cyclotrimerize 1,6-hexamethylene diisocyanate, the method described in JP-A-01-33115 can be used. The polyisocyanate used in the present invention can be used in combination with other aliphatic diisocyanates, alicyclic diisocyanates, etc., or prepolymers thereof, and a polyisocyanate content of 99% by weight or more is used.

The polyisocyanate used in the present invention may have an NCO% of 15 to 25% by weight, and more preferably has an NCO% of 20 to 25% by weight. If it is less than 15% by weight, the strength of the coating film may be insufficient, and if it exceeds 25% by weight, the amount of polyisocyanate with an isocyanurate structure will decrease, and conversely, the amount of polyisocyanate that is not trimerized, such as diisocyanate, will increase, similarly resulting in insufficient coating film strength.

The viscosity of the polyisocyanate used in the present invention is preferably 500 to 3500 mPa·s/25°C. If it is less than 500 mPa·s, the strength of the coating film may be insufficient, and if it exceeds 3500 mPa·s, the workability when applying it to the base concrete surface may decrease.

The polyisocyanate used in the present invention is 5 to 15 parts by weight per 100 parts by weight of the total composition. If it is less than 5 parts by weight, the strength of the coating film may be insufficient, and if it is more than 15 parts by weight, the curing time may be too short, resulting in insufficient workability.

The organometallic catalyst used in the present invention is blended to accelerate the curing of the composition, and examples of the organometallic catalysts that can be used include tin octylate, tin oleate, tin laurate, dibutyltin diacetate, dibutyltin diacetylacetonate, dibutyltin dilaurate, dibutyltin dichloride, lead octylate, lead naphthenate, and bismuth octylate. Among these curing catalysts, organotin compounds are more preferred. Among these curing catalysts, dibutyltin diacetylacetonate, dibutyltin diacetate, dibutyltin dilaurate, and dibutyltin dichloride are more preferred in terms of catalytic effect. The amount of the organometallic catalyst blended is 0.001 to 0.01 parts by weight per 100 parts by weight of the total composition. If the amount is less than 0.001 parts by weight, the strength of the coating film may be insufficient, and if the amount is more than 0.01 parts by weight, the curing may be too fast, resulting in poor workability when applying with a metal trowel, etc.

The hydraulic cement used in the present invention is preferably mainly white Portland cement so as to impart a specific color tone, and other materials such as ordinary Portland cement, alumina cement, blast furnace cement, and high-early-strength Portland cement can also be used in combination. The amount of hydraulic cement is preferably 5 to 15 parts by weight per 100 parts by weight of the total composition; if it is less than 5 parts by weight, the strength of the coating film decreases, and if it exceeds 15 parts by weight, the workability of applying the composition to the base concrete surface with a metal trowel or the like decreases.

The aggregates used in the hydraulic polymer cement composition of the present invention are a combination of insulator powder with a particle size of 1.0 to 3.0 mm, silica sand with a particle size of 0.6 to 2.36 mm, silica sand with a particle size of 0.21 to 1.18 mm, silica sand with a particle size of 0.15 to 0.85 mm, silica sand with a particle size of 0.05 to 0.6 mm, and silica sand with a particle size of 0.04 to 0.3 mm. Insulator powder is made by crushing insulators that have been broken or discarded at insulator production plants, and has the effect of imparting the strength, abrasion resistance, heat resistance, etc. of ceramics to floors. If the particle size is less than 1.0 mm, the workability of applying to the floor base concrete will be poor, and if it exceeds 3.0 mm, the dispersibility in the composition and the unevenness of the coating surface after hardening will be too large.

Silica sand with a particle size of 0.6 to 2.36 mm corresponds to silica sand No. 3, silica sand with a particle size of 0.21 to 1.18 mm corresponds to silica sand No. 4, silica sand with a particle size of 0.15 to 0.85 mm corresponds to silica sand No. 5, silica sand with a particle size of 0.05 to 0.6 mm corresponds to silica sand No. 6, and silica sand with a particle size of 0.04 to 0.3 mm corresponds to silica sand No. 7. For example, the combined ratio of insulator powder with a particle size of 1.0 to 3.0 mm, silica sand with a particle size of 0.21 to 1.18 mm, and silica sand with a particle size of 0.04 to 0.3 mm is preferably 8-12:60-100:0.5-2.0 by weight from the standpoint of application workability, strength expression, impact resistance, etc. when applying 5 to 9 mm to the floor base concrete. For example, the combined ratio of insulator powder with a particle size of 1.0 to 3.0 mm, silica sand with a particle size of 0.21 to 1.18 mm, and silica sand with a particle size of 0.05 to 0.6 mm is 0.8 to 1.2:2.0 to 4.0:0.3 to 1.0 by weight, which is preferable from the standpoint of application workability, strength expression, impact resistance, etc., when applying the powder to a thickness of about 2.5 to 5 mm to the floor base concrete.

The amount of aggregate to be mixed is 70 to 85 parts by weight per 100 parts by weight of the total composition. If it is less than 70 parts by weight, the smoothness of the coating film may be poor, and if it is more than 85 parts by weight, the impact resistance may decrease.

In addition to the above, it is preferable to add hydrated lime to the water-independent polymer cement composition of the present invention. The hydrated lime absorbs carbon dioxide gas generated by the urea reaction between polyisocyanate and water, and has the effect of preventing the carbon dioxide gas generated when the composition is applied to the floor base concrete and hardens from concentrating in specific areas and pushing up the coating film, causing swelling.

The hydraulic polymer cement composition of the present invention is applied to the surface of the base concrete using a metal or wooden trowel, to a thickness of 2.5 to 9 mm. Preferably, the composition is first spread and applied to the surface of the base concrete using a wooden trowel, and then the composition is applied to the surface of the base concrete to be worked on, evenly distributed to the desired thickness, and then the composition is applied to the base concrete while being firmly pressed down with a metal trowel as a finishing touch, so that it becomes one with the base concrete. This results in a coating film without defects in the hardened coating and an aesthetically pleasing coating floor.

The following provides a detailed explanation in the examples and comparative examples.

<Examples and Comparative Examples>
The water-dispersible polyol contained 35 to 40 parts by weight of a castor oil -based trifunctional polyol having a hydroxyl equivalent of 350, 5 to 10 parts by weight of a tetrafunctional polyol having a bisphenol A skeleton having a hydroxyl equivalent of 360, 20 to 25 parts by weight of a sulfonic acid ester compound (Mezamol; product name, manufactured by Bayer) as a diluent, and 30 parts by weight of water (ion-exchanged water), totaling 100 parts by weight. The water-dispersible polyol A contained a hydroxyl equivalent of 500 to 800 and a castor oil-based trifunctional polyol having a hydroxyl equivalent of 280 to 40 parts by weight. water-dispersed polyol B (water content: 25-30% by weight) containing 25-33 parts by weight of castor oil-based bifunctional polyol per 100 parts by weight of castor oil-based trifunctional polyol, with an overall hydroxyl equivalent of 200-250; and water-dispersed polyol D (water content: 25-30% by weight) containing 14-20 parts by weight of castor oil-based bifunctional polyol per 100 parts by weight of castor oil-based trifunctional polyol, with an overall hydroxyl equivalent of 200-500; The polyisocyanate A was hexamethylene diisocyanurate (viscosity 2500 mPa·s/25°C, NCO%: 20% by weight, polyisocyanate content 99% by weight or more) and the polyisocyanate B was 4,4'-diphenylmethane diisocyanate (NCO%: 31.0% by weight). The organometallic catalyst was Neostan U220H (dibutyltin diacetylacetonate). The aggregate was a ceramic powder with a particle size of 1.0 to 3.0 mm. Using silica sand having a particle size of 0.21 to 1.18 mm: Tohoku Silica Sand No. 4 (trade name, manufactured by Tohoku Silica Sand Co., Ltd.), silica sand having a particle size of 0.05 to 0.6 mm: Tohoku Silica Sand No. 6 (trade name, manufactured by Tohoku Silica Sand Co., Ltd.), silica sand having a particle size of 0.04 to 0.3 mm: Tohoku Silica Sand No. 7 (trade name, manufactured by Tohoku Silica Sand Co., Ltd.), and white Portland cement (manufactured by Taiheiyo Cement Corporation) as hydraulic cement, hydraulic polymer cement compositions of the Examples and Comparative Examples were prepared according to the blending ratios shown in Table 1. In the following evaluations, Example 1, Comparative Examples 1 to 3, Comparative Example 7, and Comparative Example 9 were evaluated after finishing to a coating thickness of 7 mm, and Example 2, Comparative Examples 4 to 6, Comparative Example 8, and Comparative Example 10 were evaluated after finishing to a coating thickness of 3 mm.

<Evaluation items and evaluation methods>

<Paint finish>
The hydraulic polymer cement compositions of the Examples and Comparative Examples were applied to a specified thickness with a metal trowel onto the surface of a dried JIS A5371 concrete slab measuring 300 mm x 300 mm x 60 mm thick (5% or less measured with a HI-520 concrete moisture meter in a concrete range) at 23°C, and the surface condition of the coating film was visually observed. A smooth finish was rated as ◯, and an uneven finish was rated as ×.

<Impact resistance>
The hydraulic polymer cement compositions of the Examples and Comparative Examples were applied to a specified thickness with a metal trowel onto the surface of a dried JIS A5371 concrete slab (5% or less measured with a HI-520 concrete range moisture meter) at 23° C. After curing for 7 days, a 1 kg steel ball was dropped 60 times from a height of 1 m onto the center of the slab, and the coating was rated as ◯ if there were no abnormalities such as cracks or peeling, and x if there were abnormalities such as cracks or peeling.

<Compressive strength>
The hydraulic polymer cement compositions of the Examples and Comparative Examples were cured at 23°C and the compressive strength (N/ ^mm2 ) of the cured products after 7 days of curing was measured in accordance with the provisions of JIS K 6911. The size of the test specimen was 13 mm x 13 mm x 25 mm. If the compressive strength was more than 22 N/ ^mm2, it was evaluated as having sufficient strength and was evaluated as ○, and if it was less than this, it was evaluated as ×.

<Thermal shock resistance and microcrack resistance>
A dried JIS A5371 concrete plate measuring 300 mm x 300 mm x 60 mm thick (5% or less measured with a Kett moisture meter HI-520 concrete range) was cut into quarters to obtain a test plate measuring 150 mm x 150 mm x 60 mm thick. The surface of the test plate was thoroughly roughened with sandpaper #80 to remove the brittle layer, and the hydraulic polymer cement compositions of the Examples and Comparative Examples were mixed uniformly and applied to a thickness of 7 mm for the hydraulic polymer cement compositions of Example 1, Comparative Examples 1 to 3, Comparative Example 7, and Comparative Example 9, or to a thickness of 3 mm for the hydraulic polymer cement compositions of Example 2, Comparative Examples 4 to 6, Comparative Example 8, and Comparative Example 10, and cured for 7 days. After that, 95°C hot water was run down the centre of the test piece for 5 minutes, followed by 20°C cold water for 10 minutes. This cycle was repeated 6,000 times for the 7 mm thick test piece, and 4,000 times for the 3 mm thick test piece. Those that showed no abnormalities such as peeling or lifting in the coating were rated as ◯ for thermal shock resistance, and those that showed abnormalities were rated as ×. Those that showed fine cracks on the coating surface were rated as × for fine crack resistance, and those that did not show fine cracks were rated as ◯.

<Adhesion>
The hydraulic polymer cement compositions of the Examples and Comparative Examples were applied to a specified thickness with a metal trowel onto the surface of a dried JIS A5371 concrete slab measuring 300 mm x 300 mm x 60 mm (5% or less measured with a HI-520 concrete range moisture meter) at 23°C. After curing for 7 days, the adhesive strength (N/ ^mm2 ) between a 40 x 40 mm portion of the hydraulic polymer cement composition and the concrete slab was measured using a Construction Research Institute type adhesion tester. The state of failure was evaluated as ◯ when 100% cohesive failure of the base concrete was observed, and x otherwise.

<Peeling resistance>
For the hydraulic polymer cement compositions of Example 1, Comparative Examples 1 to 3, 7, and 9, the hardened products were molded into strips measuring 160 mm in length, 10 mm in width, and 7 mm in thickness, and for the hydraulic polymer cement compositions of Example 2, Comparative Examples 4 to 6, 8, and 10, the hardened products were molded into strips measuring 160 mm in length, 10 mm in width, and 3 mm in thickness, and the shrinkage strain L (mm) was measured after curing at 23° C. for 7 days and then heat curing for 14 days at 50° C. Next, the specimens were pulled in the longitudinal direction at a speed of 1 mm/min to measure the tensile elastic modulus E (N/mm ² ). The shrinkage stress (N/ ^mm2 ) per unit cross-sectional area of the coating film was calculated from the shrinkage strain amount L (mm) and the length _L0 (mm) of the test specimen after aging at 23°C for 7 days using the following formula (1). Furthermore, the coating film thickness was multiplied by 7 mm for Example 1, Comparative Examples 1 to 3, Comparative Example 7, and Comparative Example 9, and by 3 mm for Example 2, Comparative Examples 4 to 6, Comparative Example 8, and Comparative Example 10 to determine the coating film shrinkage force T (N/mm) per unit width of the coating film.
Contraction stress (N/mm ² )=E(L/L ₀ ) (1)
Here, since the coating film contraction force T (N/mm) is empirically considered to act in a direction that causes the coating film to peel off, it is assumed, based on a model and experience, that this coating film contraction force acts to pull the coating film at a shallow angle of about 5 degrees as shown in Figure 1, causing the coating film to peel off, and was converted into a vertical force Tv (N/mm) per unit width (mm) of the coating film using the following equation (2).
Vertical force Tv (N/mm) = sin5° × T (2)
Because the coating thickness is as thick as 7 mm or 3 mm, this vertical force Tv (N/mm) per unit width (1 mm) is experimentally and empirically considered to act on 1 ^mm2 of the base to which the coating is adhered, and this vertical force acts to pull the coating perpendicularly to the unit surface area (1 ^mm2 ) of the base concrete, and this was taken as the vertical stress _Tv2 (N/ ^mm2 ).

Based on this, first, the normal stress Tv2 (N/mm2) was compared with Figure 2, which shows the relationship between the surface tensile strength of the base concrete and the laitance residual rate when the water/cement ratio is 60% (see Table 1 and Figure 12 (air-dried state) of the Influence of Base Concrete on the Occurrence of Blisters in Coated Floors, Journal of Structural Engineering, Architectural Institute of Japan, No. ⁴⁹³ , pp. 1-7, March 1997. Only the base cohesive failure is extracted and illustrated from Figure ₁₂ (air-dried state)), and it was determined that even if 100% of the laitance remained in the base concrete, the surface tensile strength of the base would be 0.7 N/ ^mm2 (usually, base concrete from which all laitance has been removed is the base concrete specification suitable for the application of coated floor materials), and if the normal stress _Tv2 (N/ ^mm2 ) is smaller than 0.7 N/ ^mm2 , the coating film will not peel off from the base concrete due to the action of the shrinkage force of the coating film alone, and was evaluated as excellent. When the normal stress _Tv2 (N/ ^mm2 ) was greater than the surface tensile strength of the base concrete of 0.7 N/ ^mm2 (latence residual rate 100%), the coating film was rated as ×, since the coating film may destroy the surface of the base concrete and peel off due to the action of the shrinkage force of the coating film alone.

In addition, the 2012 edition of the Painted Floor Handbook (published March 1, 2012, supervised by Yokoyama Yutaka, edited and written by the Japan Painted Floor Industry Association, published and sold by Kobunsha) specifies that the surface (tensile) strength of newly constructed concrete/mortar and renovated base materials that serve as the base for painted floors should be 1.5 N/ ^mm2 . Therefore, by comparing this 1.5 N/ ^mm2 with the normal stress _Tv2 (N/ ^mm2 ), if the normal stress _Tv2 (N/ ^mm2 ) is smaller than 1.5 N/ ^mm2 , it is considered that the coating film will not peel off from the base concrete due to the action of the coating film's shrinkage force alone, and it is evaluated as ○. If the normal stress _Tv2 (N/ ^mm2 ) is greater than the surface (tensile) strength of 1.5 N/ ^mm2 , it is evaluated as ×, since the coating film may destroy the surface of the base concrete and peel off due to the action of the coating film's shrinkage force alone.

Of the above two judgments, if the judgment is ^○ at least at the specified value of 1.5 N/mm2 in the Coating Floor Handbook, it is judged that the peeling resistance is good, and if both are ×, it is judged that a groove 7 to 13 mm deep and 7 to 13 mm wide should be made at the edge of the floor base concrete, as in the past, and if the distance between opposing grooves exceeds 12 m, joints 7 to 13 mm deep and 7 to 13 mm wide should be made every 12 m from the groove, and the composition should be applied onto the floor base concrete while filling the grooves and joints.

<Yellowing resistance>
For the hydraulic polymer cement compositions of Example 1, Comparative Examples 1 to 3, 7, and 9, a 7 mm-thick cured coating film was irradiated with a black light (germicidal lamp, peak wavelength 256 nm, 31 μW/cm ² ) from a height of 50 cm for 200 hours, and the color difference (ΔE) before and after irradiation was measured. A ΔE of 1.0 or less was evaluated as ○, and a ΔE of more than 1.0 was evaluated as ×.

<Evaluation Results>
The evaluation results are shown in Table 2.

Claims (3)

A hydraulic polymer cement composition comprising a water-dispersible polyol, a polyisocyanate, an organometallic catalyst, glycerin, a hydraulic cement, and an aggregate,
the water-dispersible polyol contains water, a castor oil-based trifunctional polyol, and a tetrafunctional polyol having a bisphenol A skeleton, has a hydroxyl equivalent of 500 to 800, and is 4 to 10 parts by weight per 100 parts by weight of the total composition;
the castor oil-based trifunctional polyol is more than 30 parts by weight and not more than 50 parts by weight based on 100 parts by weight of the water-dispersible polyol,
the content of the tetrafunctional polyol having a bisphenol A skeleton is more than 2 parts by weight and not more than 15 parts by weight based on 100 parts by weight of the water-dispersible polyol,
The amount of the organometallic catalyst is 0.001 to 0.01 parts by weight based on 100 parts by weight of the total composition.
The amount of glycerin is more than 0 parts by weight and not more than 5 parts by weight per 100 parts by weight of the total composition,
The polyisocyanate is an aliphatic isocyanurate, and the polyisocyanate is 5 to 15 parts by weight per 100 parts by weight of the total composition;
The hydraulic cement is 5 to 15 parts by weight based on 100 parts by weight of the total composition.
The aggregate is 70 to 85 parts by weight per 100 parts by weight of the total composition.
A hydraulic polymer cement composition comprising: The hydraulic polymer cement composition according to claim 1, characterized in that the polyisocyanate is hexamethylene diisocyanurate. A method for applying the hydraulic polymer cement composition according to claim 1 or 2, which comprises applying the hydraulic polymer cement composition to a surface of a floor base concrete in a thickness of 2.5 to 10 mm.