JP6208533B2 - Water-based polyurethane composition and method for applying the same to floor concrete - Google Patents

Description

  The present invention relates to a water-based polyurethane composition having good coating workability and quick surface hardening even at low temperatures in winter and a method for applying the same to floor concrete, particularly floors of food factories where hot water flows down. The coating film does not peel off even when hot water of 95 ° C. repeatedly flows, and the coating film does not crack or peel off even if a heavy object falls. The present invention relates to a water-based polyurethane composition that prevents a pedestrian from slipping and falling even when a floor on which a polyurethane composition has been applied and cured is wet, and a method for applying the same to floor concrete.

  Conventionally, a curable polymer cement composition having a practically sufficient pot life and excellent low-temperature curability has been proposed (Patent Document 1). The curable polymer cement composition is a curable polymer cement composition containing a polyol, a catalyst, a polyisocyanate, a cement, an aggregate and water, and is represented by the general formula (1) described in Patent Document 1 as a catalyst. A curable polymer cement composition using the imidazole compound and dimorpholinodiethyl ether represented.

JP 2004-67419 A

  However, even though the curable polymer cement composition is excellent in low-temperature curability, the technical scope described in Patent Document 1 may not be sufficient, and hot water at 95 ° C repeatedly flows down. In a usage environment where the paint film peels off or the weight falls, the paint film may crack and peel off, and the paint film surface is covered with resin, so water remains on the paint film. There was a problem that the pedestrian might slip and fall when doing so.

  The problem to be solved by the present invention is that the coating workability is good and the surface curing is fast even at 5 ° C., and the coating film is peeled off even when hot water at 95 ° C. is repeatedly flowed, or a heavy object falls. A water-based polyurethane composition in which a coating film is not cracked and peeled, and a pedestrian does not slip and fall even when a floor where the water-based polyurethane composition of the present invention is applied and cured is wet. It is in providing the construction method to this floor foundation concrete.

The invention according to claim 1 is a hydraulic polymer cement composition comprising a polyol, a catalyst, polyisocyanate, cement, aggregate and water, wherein the polyol has a castor oil-modified trifunctional polyol and a bisphenol A skeleton. It consists of a tetrafunctional polyol and a bifunctional polyether polyol having a bisphenol A skeleton. The catalyst is composed of an imidazole compound and dimorpholinodiethyl ether, and further contains an alcohol compound having a hydroxyl group equivalent of 100 to 200 and one hydroxyl group, The oil-modified trifunctional polyol and the tetrafunctional polyol having a bisphenol A skeleton have a hydroxyl equivalent of 250 to 450, and the bifunctional polyether polyol having a bisphenol A skeleton has a hydroxyl equivalent of 150 to 250, which is a total of cement and aggregate. Number of copies Providing an aqueous polyurethane composition, which is a 75 to 90 parts by weight of the goods total of 100 parts by weight.

  In the invention according to claim 2, the time that can be mixed at 5 ° C. and coated on the floor underlay concrete with a hammer is 11 minutes or more immediately after mixing, and the thickness is 6-9 mm on the floor underlay concrete at 5 ° C. 2. The water-based polyurethane composition according to claim 1, wherein the time when the surface hardness after application is 60 in the durometer D type is within 6 hours.

  The invention according to claim 3 is to remove the brittle layer of the floor foundation concrete, provide a groove portion having a depth of 7 to 13 mm and a width of 7 to 13 mm at the edge of the floor foundation concrete, and the distance between the facing groove portion and the groove portion is When it is over 12 m, a joint part having a depth of 7 to 13 mm and a width of 7 to 13 mm is provided every 12 m from the groove part, and the water-based polyurethane composition according to claim 1 or 2 in the groove part and the joint part. 3. The water-based polyurethane according to claim 1 or 2, wherein the water-based polyurethane composition according to claim 1 or 2 is applied to the thickness of 6 to 9 mm directly on the floor foundation concrete while being filled. Provided is a method for constructing a composition on floor foundation concrete.

  Even when the water-based polyurethane composition of the present invention and the method for applying the same to the floor foundation concrete are applied at 5 ° C. in winter, the total number of cement and aggregate is 75 to 90 parts per 100 parts by weight of the whole composition. Since the blending amount of the polyol and polyisocyanate relative to the entire composition (resin blending amount) is relatively small, the coating workability is good and the surface cures quickly, and the shrinkage of the resin is the edge of the coating film. Since the force for lifting the sheet becomes small, there is an effect that the coating film does not peel even if hot water of 95 ° C. is repeatedly flowed.

  In addition, since the total number of cement and aggregate is as large as 75 to 90 parts by weight with respect to 100 parts by weight of the entire composition, the coating surface of the aqueous polyurethane composition of the present invention coated and cured on floor foundation concrete There is an effect that the pedestrian does not slip and fall even if the aggregate appears and the surface of the coating film is wet and wet with water or the like.

  The polyol is composed of a castor oil-modified trifunctional polyol, a tetrafunctional polyol having a bisphenol A skeleton, and a bifunctional polyether polyol having a bisphenol A skeleton. An alcohol compound having a hydroxyl group, a castor oil-modified trifunctional polyol and a tetrafunctional polyol having a bisphenol A skeleton have a hydroxyl equivalent of 250 to 450, and a bifunctional polyether polyol having a bisphenol A skeleton has a hydroxyl equivalent of 150 to 450. Since it is 250, the surface hardness of the coating film applied at 5 ° C. is 60 within 6 hours in the durometer D type, and there is an effect that the floor can be used early even in winter. For this reason, even in winter, the floor can be repaired overnight.

  Moreover, when applying the water-based polyurethane composition according to the present invention onto the floor foundation concrete, the brittle layer of the floor foundation concrete is removed, and a groove portion having a depth of 7 to 13 mm and a width of 7 to 13 mm is formed at the edge of the floor foundation concrete. When the distance between the opposing groove portions is more than 12 m, a joint portion having a depth of 7 to 13 mm and a width of 7 to 13 mm is provided every 12 m from the groove portion, and the inside of the groove portion and the joint portion are charged. By applying the water-based polyurethane composition according to claim 1 or 2 to a thickness of 6 to 9 mm directly on the floor foundation concrete while filling the water-based polyurethane composition according to claim 1 or claim 2 There is an effect that peeling of the coating film end due to curling of the film due to curling and lifting of the coating film occurring in a part slightly away from the coating film edge do not occur. In particular, in a food factory where hot water of about 95 ° C. flows repeatedly, there is an effect that the floor can be used in a healthy state for a long period of time because these peeling and floating do not occur.

  The present invention will be described in detail below.

  The water-based polyurethane composition of the present invention is a hydraulic polymer cement composition containing a polyol, a catalyst, a polyisocyanate, a cement, an aggregate, and water. The polyol comprises a castor oil-modified trifunctional polyol and a bisphenol A skeleton. It comprises a tetrafunctional polyol having a bifunctional polyether polyol having a bisphenol A skeleton, further comprising an alcohol compound having a hydroxyl equivalent of 100 to 200 and having one hydroxyl group, and has a castor oil-modified trifunctional polyol and a bisphenol A skeleton. The tetrafunctional polyol has a hydroxyl group equivalent of 250 to 450, the bifunctional polyether polyol having a bisphenol A skeleton has a hydroxyl equivalent of 150 to 250, and the total number of cement and aggregate is 75 in 100 parts by weight of the total composition. ~ 90 parts by weight An aqueous polyurethane composition according to, in addition to these, if necessary pigments and diluents, and dispersing agents, additives such as defoaming agent is blended.

  The polyol used in the aqueous polyurethane composition of the present invention comprises a castor oil-modified trifunctional polyol, a tetrafunctional polyol having a bisphenol A skeleton, and a bifunctional polyether polyol having a bisphenol A skeleton.

  The castor oil-modified trifunctional polyol is castor oil and derivatives thereof, for example, diglyceride, monoglyceride of castor oil fatty acid, and a mixture thereof, and is a polyol having 3 hydroxyl groups. The hydroxyl equivalent of the castor oil-modified trifunctional polyol used in the present invention is preferably 250 to 450. If it is less than 250, curing as a water-based polyurethane composition becomes fast and workability becomes poor, and if it exceeds 450, the water-based polyurethane composition as a water-based polyurethane composition. The strength after curing is insufficient.

  The tetrafunctional polyol having a bisphenol A skeleton is an epoxy ring-opening polyol obtained by reacting an active hydrogen compound with a polyepoxy compound having a bisphenol A skeleton, and the hydroxyl equivalent is preferably 250 to 450. When the hydroxyl equivalent is less than 250, curing as a water-based polyurethane composition is accelerated, resulting in poor workability. When it exceeds 450, the strength after curing as a water-based polyurethane composition is insufficient.

  The bifunctional polyetherol having a bisphenol A skeleton is a polyether polyol obtained by subjecting bisphenol A to an addition reaction of one or more alkylene oxides such as ethylene oxide and propylene oxide, and has a hydroxyl group equivalent of 150 to 250. preferable. If the hydroxyl equivalent is less than 150, curing as a water-based polyurethane composition is accelerated, resulting in poor workability. If it exceeds 250, the strength after curing as a water-based polyurethane composition is insufficient.

  In addition to the polyol, the aqueous polyurethane composition of the present invention further contains an alcohol compound having a hydroxyl group equivalent of 100 to 200 and having one hydroxyl group. When the hydroxyl equivalent is less than 100 or more than 200, the defoaming property at the time of curing becomes insufficient. As an alcohol compound having a hydroxyl equivalent of 100 to 200, there is menthol (hydroxyl equivalent 156).

  As the catalyst used in the aqueous polyurethane composition of the present invention, an imidazole compound and dimorpholinodiethyl ether are used. Examples of imidazole compounds include imidazole, 2-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, Examples include 2-phenyl-4-methylimidazole, and in particular, imidazole, 2-methylimidazole, 1,2-dimethylimidazole, and 2-ethyl-4-methylimidazole are excellent in solubility with polyols. Is suitable.

  The polyisocyanate used in the water-based polyurethane composition of the present invention has good workability, fast curability at low temperature, and high strength after curing. Therefore, 4,4′-diphenylmethane diisocyanate may be used. Although it is preferable, other aliphatic polyisocyanates, aromatic polyisocyanates, alicyclic conducting polyisocyanates, and the like can also be used, and can also be used in combination.

  The number of isocyanate groups relative to one hydroxyl group of the polyol and alcohol compound is preferably 5.5 to 6.5, and if it is less than 5.5, curing is delayed, and if it exceeds 6.5, foaming due to carbon dioxide gas may occur in the cured product. is there.

  The cement used in the water-based polyurethane composition of the present invention is mainly intended to impart a specific color tone to the white Portland cement since the water-based polyurethane composition of the present invention is applied to floor foundation concrete and imparts a beautiful appearance. It is preferable to use an agent. In addition, ordinary Portland cement, alumina cement, blast furnace cement, and early-strength Portland cement can be used in combination. The blending amount of cement is 5 to 10 parts by weight in 100 parts by weight of the whole composition.

  The aggregate used in the water-based polyurethane composition of the present invention includes an insulator powder having a particle size of 1.0 to 3.0 mm, cinnabar sand having a particle size of 0.6 to 2.36 mm, and a particle size of 0.21.硅 1.18 mm of cinnabar and particle size of 0.15 to 0.85 mm of cinnabar are used in combination. The insulator powder is obtained by pulverizing an insulator that has been damaged or discarded at an insulator factory, and has the effect of imparting the strength, wear resistance, heat resistance, etc. of ceramics to the floor. When the particle diameter is less than 1.0 mm, the workability of application to the floor foundation concrete is deteriorated, and when it exceeds 3.0 mm, the dispersibility in the composition and the unevenness of the coating surface after curing are too large.

  The cinnabar with particle diameter of 0.6-2.36 mm is No.3 cinnabar, the cinnabar with particle diameter of 0.21-1.18 mm is cinnabar No.4, and the cinnabar with particle diameter of 0.15-0.85 mm is 5 No. Insulating powder with a particle size of 1.0 to 3.0 mm, cinnabar with a particle size of 0.6 to 2.36 mm, cinnabar with a particle size of 0.21 to 1.18 mm, and a particle size of 0.15 to 0 Application ratio to floor foundation concrete is 0.9-1.1: 0.9-1.1: 1.8-2.2: 1.8-2.2 by weight. From the viewpoint of property, strength expression and impact resistance. The ratio of the total amount of potato powder and these cinnabar to the whole composition is 75 to 90 parts by weight in 100 parts by weight of the whole composition. If it is less than 75 parts by weight, the resin floats on the surface of the cured product and the slip resistance is lowered, and if it exceeds 90 parts by weight, the coating workability becomes poor.

  In addition to the above, slaked lime is preferably added to the aqueous polyurethane composition of the present invention. The slaked lime absorbs carbon dioxide gas generated by the urea reaction between polyisocyanate and water, and the carbon dioxide gas generated until the composition is applied on the floor foundation concrete and hardens to concentrate on a specific part to press the coating film. This has the effect of suppressing the occurrence of swelling.

  When applying the water-based polyurethane composition of the present invention onto the floor foundation concrete, first, a brittle layer such as latency on the floor foundation concrete surface is removed by polishing or the like, and the floor around the floor of the floor foundation concrete or around the grating is removed. When a groove portion having a depth of 7 to 13 mm and a width of 7 to 13 mm is provided by a concrete cutter or the like at the end portion as the end portion, and the distance between the facing groove portion and the groove portion exceeds 12 m, within 12 m from the groove portion A joint having a depth of 7 to 13 mm and a width of 7 to 13 mm is provided by a concrete cutter or the like. Then, the water-based polyurethane composition according to claim 1 or 2 is directly applied onto the floor foundation concrete while the groove-based portion and the joint portion are filled with the water-based polyurethane composition according to claim 1 or 2. Apply to a thickness of 6-9 mm. Within 12 m from the groove, a joint is provided within 12 m from one groove, and then within 12 m from the joint when the distance between the groove and the other groove facing the groove is greater than 12 m. If the distance between the joint part and the other groove part opposed to the joint part is more than 12 m, it means that the joint part is further provided, and as a result, all the groove parts and joint parts are provided. And the distance between the joint part and the joint part is within 12 m.

  Providing grooves and joints in the floor foundation concrete is that the aqueous polyurethane composition of the present invention shrinks the resin due to the curing reaction, and as a result, the entire aqueous polyurethane composition shrinks. The purpose is to prevent the object from peeling off. The peeling occurs remarkably in a food factory where hot water is allowed to flow down on the floor for cleaning. The size of the groove and joint is preferably 7 to 13 mm in depth and 7 to 13 mm in width from the viewpoint of work with a concrete cutter or the like and prevention of peeling. Moreover, when a joint is provided every 12 m from the groove, the coating film shrinks due to the curing reaction of the aqueous polyurethane composition of the present invention, and due to the shrinkage, near the center between the groove and the joint or between the joint and the joint. In the vicinity of the center of the film, peeling occurs due to the contraction of the coating film, and the coating film in the vicinity of the center is in a floating state.

  The thickness of the water-based polyurethane composition of the present invention applied on the floor base concrete is determined from the viewpoint of impact resistance that the heavy material falls and the coating film is cracked or peeled off, and the coating workability on the floor base concrete. From this viewpoint, 6 to 9 mm is preferable. If it is less than 6 mm, the coating workability and impact resistance become insufficient, and if it exceeds 9 mm, the absolute amount of the shrinkage force of the resin increases, and even if the grooves and joints are provided, the coating film may be peeled off or floated. There is a case.

  Hereinafter, it demonstrates concretely in an Example and a comparative example.

Example 10-15 parts by weight of castor oil-modified trifunctional polyol having a hydroxyl group equivalent of 350, 10-15 parts by weight of a tetrafunctional polyol having a bisphenol A skeleton having a hydroxyl group equivalent of 360, and a bisphenol A skeleton having a hydroxyl group equivalent of 180 5 to 10 parts by weight of a bifunctional polyether polyol having 1 to 5 parts by weight, 1 to 5 parts by weight of an alcohol compound having a hydroxyl equivalent of 156 and one hydroxyl group, and a sulfonate compound (mesamol; trade name, Bayer) as a diluent 30 parts by weight of colored toner is mixed with 270 parts by weight of a mixture of polyol, diluent and water, which is 25 parts by weight and 30 parts by weight of water (ion-exchanged water). And used as the main agent of the water-based polyurethane composition of the examples. In addition, there exists JJ-500TA (brand name, Aika Kogyo Co., Ltd. product) as a commercial item of this main ingredient. In addition, as polyisocyanate, 300 parts by weight of Crude MDI (4,4′-diphenylmethane diisocyanate) Luplanate MB-5S (trade name, manufactured by BASF INOAC Polyurethane Co., Ltd., NCO wt%: 31.4 to 32.6%) A curing agent for the aqueous polyurethane composition was used. In addition, the aggregate includes 450 parts by weight of selven (trade name, manufactured by Okumura Serum Co., Ltd.) having a particle diameter of 1.0 to 3.0 mm as galvanized powder and cinnabar sand having a particle diameter of 0.6 to 2.36 mm: dried cinnabar 3 No. (trade name, manufactured by Shinozawa Kosuna Kogyo Co., Ltd.) 450 parts by weight and silica sand having a particle diameter of 0.21-1.18 mm: 900 parts by weight of Tohoku Kosuna No. 4 (trade name, manufactured by Tohoku Kosuna Co., Ltd.), and particle diameter 0.15-0.85 mm cinnabar: Tohoku cinnabar No. 5 (trade name, manufactured by Tohoku cinnabar Co., Ltd.) 900 parts by weight, and white Portland cement (manufactured by Taiheiyo Cement Co.) as 270 parts by weight Aggregates and cements of the aqueous polyurethane compositions of the examples were used.

  Aggregate and cement are prepared by mixing the above-mentioned insulator powder, three types of cinnabar sand, and white Portland cement in advance, and adding 30 parts by weight of slaked lime to the cement aggregate part of the aqueous polyurethane composition of the example. did. In the application to the floor base concrete and the evaluation of the following evaluation items, 300 parts by weight of the main agent of the above example, 300 parts by weight of the curing agent of the example, 3000 parts by weight of the cement aggregate part of the example, an imidazole compound and dimorpholinodiethyl A catalyst part JJ-500R (trade name, manufactured by Aika Kogyo Co., Ltd.) in which ether and water are mixed at 1: 1: 18 is blended, and the catalyst part is added to a total of 3600 parts by weight of the main agent, the curing agent, and the cement aggregate part. An aqueous polyurethane composition of the example was added at an additional 5% by weight.

Comparative Examples 1 to 3
35 to 40 parts by weight of a castor oil-modified trifunctional polyol having a hydroxyl group equivalent of 350, 3 to 8 parts by weight of a tetrafunctional polyol having a bisphenol A skeleton having a hydroxyl group equivalent of 360, and a sulfonic acid ester compound (mesamol; 30 parts by weight of color toner is added to 270 parts by weight of a mixture of polyol and water, including 20 to 25 parts by weight of a trade name (manufactured by Bayer) and 30 parts by weight of water (ion exchange water). It mixed and it was set as the main ingredient of the water-based polyurethane composition of a comparative example. In addition, 300 parts by weight of Crude MDI (4,4′-diphenylmethane diisocyanate) Rupranate MB-5S (trade name, manufactured by BASF INOAC Polyurethane Co., Ltd., NCO weight%: 31.4 to 32.6%) is used as a polyisocyanate as a comparative example. A curing agent for an aqueous polyurethane composition was used.

  The aggregate and cement of the comparative example were the same as the aggregate and cement of the example, and the cement aggregate part of the comparative example was also the same as the cement aggregate part of the example. In the application to the floor base concrete and the evaluation of the following evaluation items, 300 parts by weight of the main agent of the comparative example, 300 parts by weight of the curing agent of the comparative example, 3000 parts by weight of the cement aggregate part of the comparative example, and further an imidazole compound and dimorpholinodiethyl ether And catalyst part JJ-500R (trade name, manufactured by Aika Kogyo Co., Ltd.) in which 1: 1 and 18 are mixed with water, and the catalyst part is added to a total of 3600 parts by weight of the main agent, the curing agent and the cement aggregate part. Further, 3% by weight was added as the aqueous polyurethane composition of Comparative Example 1, and 5% by weight of the catalyst was similarly added as the aqueous polyurethane composition of Comparative Example 2, and the catalyst was further added in the same manner. The aqueous polyurethane composition of Comparative Example 3 was added with 7% by weight.

Evaluation items and evaluation methods

5 ° C. Curability Under 5 ° C., the water-based polyurethane compositions of Examples and Comparative Examples 1 to 3 that were uniformly mixed were applied on the floor foundation concrete to a thickness of 6 to 9 mm with a gold trowel, and the surface hardness was In the durometer hardness D type specified in JIS K7215, the time of 60 or more was evaluated as “◯” when the time of 6 hours or less was evaluated as “◯”.

5 ° C working time Under 5 ° C, the time in which the aqueous polyurethane compositions of Examples and Comparative Examples 1 to 3 mixed uniformly on floor foundation concrete can be applied with a gold trowel to a thickness of 6 to 9 mm in minutes. It was evaluated as ◯, and 11 minutes or more were evaluated as ◯, and 10 minutes or less as x.

5 ° C. Surface finish at 5 ° C. Coating film obtained by applying the aqueous polyurethane compositions of Examples and Comparative Examples 1 to 3 uniformly mixed on floor foundation concrete to a thickness of 6 to 9 mm with a gold trowel. The surface state was visually observed, and a case where the surface was smooth was evaluated as ◯, and a case where the surface was uneven was evaluated as ×.

On the surface of impact 23 ° C. under JISA5371 300mm × 300mm × thickness 60mm dry concrete slab of (less than 5% by ket moisture meter HI-520 concrete range) were uniformly mixed Examples and Comparative Example 1 Thoroughly apply the water-based polyurethane composition of Comparative Example 3 to a thickness of 6-9 mm with a gold trowel and cure for 7 days. Drop a steel ball with a height of 1 m to 1 kg 30 times in the center, cracking and peeling off the coating film. Those having no abnormality such as ◯ were evaluated, and those having abnormality such as cracking and peeling were evaluated as ×.

Thermal shock resistance JIS A5371 300 mm x 300 mm x 60 mm thick dry concrete flat plate (5% or less in ket moisture meter HI-520 concrete range) cut to 1/4 and test 150 mm x 150 mm x thickness 60 mm As a plate, a joint portion having a depth of 10 mm and a width of 10 mm is provided on the surface of the test plate and 5 mm inside the four ends. At 23 ° C., the joints are applied to a thickness of 6 to 9 mm and cured for 7 days while filling the joints with the aqueous polyurethane compositions of Examples and Comparative Examples 1 to 3. Thereafter, 95 ° C hot water is allowed to flow down to the center of the test body for 5 minutes, and then 20 ° C cold water is allowed to flow down for 10 minutes. The cycle is repeated 4000 cycles. An abnormality was evaluated as x.

On the surface of the slip resistant 23 ℃ under JISA5371 300mm × 300mm × thickness 60mm dry concrete slab (less than 5% by ket moisture meter HI-520 concrete range), Examples and Comparative Examples 1 to were uniformly mixed The aqueous polyurethane composition of Comparative Example 3 was applied to a thickness of 6 to 9 mm with a gold trowel and cured for 7 days. The surface of the coating film was in a dry state and in a wet state with water using a portable skid resistance tester. BPN values were measured. A BPN value of 40 or more was evaluated as ◯.

On the surface of the dried concrete slab of 300 mm × 300 mm × thickness 60mm adherent 23 ° C. under JISA5371 (less than 5% by ket moisture meter HI-520 concrete range), Examples and Comparative Examples 1 to were uniformly mixed The aqueous polyurethane composition of Comparative Example 3 was applied to a thickness of 6 to 9 mm with a gold trowel and cured for 7 days, and the 40 × 40 mm portion of the aqueous polyurethane composition and the concrete flat plate were adhered using a Kenken adhesive strength tester. The strength was measured. As for the fracture state, 100% cohesive fracture of the ground concrete was evaluated as “good”, and the others were evaluated as “poor”.

Evaluation results The evaluation results are shown in Table 1.

Summary In all of the evaluation items, the evaluation results were evaluated as o, but in the comparative example, the 5 ° C. curability was evaluated as x, or the 5 ° C. pot life and surface finish were evaluated as x.

Claims (3)

A hydraulic polymer cement composition comprising a polyol, a catalyst, a polyisocyanate, a cement, an aggregate and water, wherein the polyol comprises a castor oil-modified trifunctional polyol, a tetrafunctional polyol having a bisphenol A skeleton, and a bisphenol A skeleton. The catalyst comprises an imidazole compound and dimorpholinodiethyl ether, and further contains an alcohol compound having a hydroxyl equivalent of 100 to 200 and one hydroxyl group, castor oil-modified trifunctional polyol and bisphenol A. The tetrafunctional polyol having a skeleton has a hydroxyl equivalent of 250 to 450, the bifunctional polyether polyol having a bisphenol A skeleton has a hydroxyl equivalent of 150 to 250, and the total number of parts of cement and aggregate is 100 parts by weight of the total composition During ~ 75-90 aqueous polyurethane composition, which is a part by weight.   Mixing at 5 ° C and applying on a gold-plated concrete on the floor base concrete is 11 minutes or more immediately after mixing, and when applied to the floor base concrete at 5 ° C to a thickness of 6 to 9 mm, The water-based polyurethane composition according to claim 1, wherein the time for which the surface hardness is 60 in the durometer D type is 6 hours or less. When the brittle layer of the floor foundation concrete is removed and a groove portion having a depth of 7 to 13 mm and a width of 7 to 13 mm is provided at the edge of the floor foundation concrete, and the distance between the facing groove portion and the groove portion exceeds 12 m, the groove portion A floor base concrete is provided with a joint portion having a depth of 7 to 13 mm and a width of 7 to 13 mm every 12 m from the inside and filling the water-based polyurethane composition according to claim 1 or 2 into the groove portion and the joint portion. The water-based polyurethane composition according to claim 1 or 2 is directly applied to a thickness of 6 to 9 mm directly on the floor-based concrete of the water-based polyurethane composition according to claim 1 or 2. Construction method.