Waterborne polyurethane floor coating and preparation method thereof

Abstract

The invention provides a waterborne polyurethane floor coating and a preparation method thereof. The waterborne polyurethane floor coating disclosed by the invention comprises the following components in parts by mass: 10-20 parts of an isocyanate composition; 8-22 parts of a water-based mortar emulsion; 60-80 parts of an active sand material; the isocyanate composition comprises a compound as shown in a formula I and an adduct thereof: # imgabs0 #, in the formula I, R is phenyl or substituted phenyl, and a substituent group in the substituted phenyl is selected from C1-C6 alkyl, C1-C6 alkoxy or halogen; l is-CH2 <->,-CH2CH2 <-> or-C (CH3) 2 <->; and n is 2 or 3. The waterborne polyurethane floor coating disclosed by the invention has relatively high reaction activity, flowability, mechanical strength and weather resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of floor coatings and relates to a waterborne polyurethane floor coating and a preparation method thereof. Background Art

[0002] Waterborne polyurethane mortar floor coating is a widely used hybrid floor paving product. The material is currently mainly composed of diphenylmethane diisocyanate (MDI), water-based emulsion, and cement sand. This type of product has the advantages of seamlessness, wear resistance, high temperature cleaning resistance, chemical corrosion resistance, and rapid curing. Compared with non-aqueous polyurethane floors, epoxy floors, and polyurea floors, waterborne polyurethane mortar floors have more significant high temperature cleaning resistance and are more suitable for food processing workshops, central kitchens, and other places that need to be exposed to hot water and steam. In addition, this product combines the characteristics of polyurethane and inorganic cement mortar, has excellent wear resistance and compression resistance, and is suitable for forklift operations, heavy object handling, and warehouses and AGV workplaces that are prone to oil pollution.

[0003] However, the weather resistance of the waterborne polyurethane floor coating formed by the existing MDI isocyanate component is poor, and yellowing occurs easily, which greatly reduces its maintainability. In addition, the waterborne polyurethane floor coating formed by isocyanate components such as hexamethyl diisocyanate (HDI) and isophorone diisocyanate (IPDI) has good weather resistance and is not prone to yellowing, but the reactivity of such products is low, and the hardness is slow to build up, thereby causing the inorganic matter in the system to settle, and then affecting the strength of the product. Adding a catalyst to the product can accelerate the reactivity, and then avoid the sedimentation of inorganic matter in the system, but after adding a catalyst, the reaction of isocyanate and water will be accelerated, resulting in an increase in floor blistering, and then also unfavorable to the strength of the product.

[0004] In summary, how to obtain a waterborne polyurethane floor coating with good reactivity, strength and weather resistance is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] In view of the defects existing in the prior art, the present invention provides a waterborne polyurethane floor coating and a preparation method thereof. The present invention enables the waterborne polyurethane floor coating to have high reactivity, fluidity, mechanical strength and weather resistance by making the waterborne polyurethane floor coating include an isocyanate composition formed by a compound shown in Formula I and an adduct thereof.

[0006] The first aspect of the present invention provides a waterborne polyurethane floor coating, which comprises the following components in parts by mass:

[0007] 10 to 20 parts of isocyanate composition;

[0008] 8-22 parts of water-based mortar emulsion;

[0009] 60-80 parts of active sand;

[0010] The isocyanate composition comprises a compound shown in formula I and an adduct thereof:

[0011]

[0012] In formula I, R is phenyl or substituted phenyl, the substituent in the substituted phenyl is selected from C1-C6 alkyl, C1-C6 alkoxy or halogen; L is -CH2-, -CH2CH2- or -C(CH3)2-; n is 2 or 3.

[0013] The waterborne polyurethane floor coating as described above, wherein the compound represented by formula I is selected from one or more of the following compounds:

[0014]

[0015] The waterborne polyurethane floor coating as described above, wherein the adduct of the compound represented by formula I includes an adduct of the compound represented by formula I and trimethylolpropane and / or a polymer of the compound represented by formula I.

[0016] In the waterborne polyurethane floor coating as described above, the isocyanate composition comprises 70% to 99% of the compound represented by formula I and 1% to 29% of the adduct of the compound represented by formula I in terms of mass percentage.

[0017] As mentioned above, the water-based polyurethane floor coating, wherein the water content of the water-based mortar emulsion is 10wt% to 45wt%, preferably 20wt% to 40wt%.

[0018] The water-based polyurethane floor coating as described above, wherein the water-based mortar emulsion includes a defoamer.

[0019] In the waterborne polyurethane floor coating as described above, the active sand material comprises one or more of cement, slaked lime and quartz sand.

[0020] In the waterborne polyurethane floor coating as described above, the active sand material comprises 10 to 15 parts by mass of cement, 1 to 5 parts by mass of slaked lime and 50 to 60 parts by mass of quartz sand.

[0021] In the water-based polyurethane floor coating as described above, the quartz sand comprises a mixture of medium sand and fine sand; the average particle size of the medium sand is 0.5-0.35 mm; and the average particle size of the fine sand is 0.35-0.25 mm.

[0022] A second aspect of the present invention provides a method for preparing the waterborne polyurethane floor coating as described above, comprising the following steps:

[0023] The isocyanate composition is mixed with the aqueous mortar emulsion, and then the active sand material is added and mixed to obtain the aqueous polyurethane floor coating.

[0024] The implementation of the present invention has at least the following beneficial effects:

[0025] The waterborne polyurethane floor coating of the present invention includes an isocyanate composition formed by the compound shown in formula I and its adduct, wherein the compound shown in formula I is a polyisocyanate compound with a benzene ring, and the NCO group in the compound is a non-conjugated structure with the benzene ring, and its ultraviolet absorption capacity is relatively weak, and the yellowing phenomenon of the floor coating caused by light radiation can be avoided, thereby improving its weather resistance, in addition, the electron donating effect of the benzene ring makes the coating have a higher reactivity, and the rigidity of the benzene ring makes the coating have a higher strength, and the composition formed by the compound shown in formula I and its adduct can make the isocyanate composition have a moderate viscosity and a higher functionality, so that the coating has a higher degree of crosslinking while maintaining good fluidity, thereby obtaining better strength. In summary, the waterborne polyurethane floor coating of the present invention uses the isocyanate composition, water-based mortar emulsion and active sand material with a specific structure in a compounded manner according to a specific mass fraction, so that the floor coating has both high reactivity, fluidity, mechanical strength and weather resistance. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Current waterborne polyurethane floor coating is mainly formed by isocyanate component with diphenylmethane diisocyanate (MDI), and the isocyanate group of diphenylmethane diisocyanate is directly conjugated with benzene ring, so its ultraviolet light absorption ability is stronger, and weather resistance is poor, and yellowing phenomenon occurs easily. For improving the weather resistance of waterborne polyurethane floor coating, it is also reported in the prior art that isocyanate component without conjugated structure such as aliphatic and alicyclic etc. such as HDI, IPDI is used to form waterborne polyurethane floor coating, although the weather resistance of coating is significantly improved, the reactivity of such products is low, and hardness is slow to establish, which is unfavorable for the improvement of product strength. Therefore, the present invention considers starting with isocyanate component, by the selection of isocyanate component so that waterborne polyurethane floor coating has good reactivity, strength and weather resistance concurrently.

[0028] Based on this, the first aspect of the present invention is a waterborne polyurethane floor coating, which comprises the following components in parts by mass:

[0029] 10 to 20 parts of isocyanate composition;

[0030] 8-22 parts of water-based mortar emulsion;

[0031] 60-80 parts of active sand;

[0032] Wherein, the isocyanate composition comprises a compound shown in formula I and an adduct thereof:

[0033]

[0034] In formula I, R is phenyl or substituted phenyl, wherein the substituent in the substituted phenyl is selected from C1-C6 alkyl, C1-C6 alkoxy or halogen; L is -CH2-, -CH2CH2- or -C(CH3)2-; and n is 2 or 3.

[0035] Aqueous mortar emulsion is a polymer emulsion used to enhance the performance of cement mortar, and its composition generally includes polymer resin emulsion and water, wherein the polymer resin emulsion can give the mortar stronger adhesion, flexibility and crack resistance, and water, as one of the main components of the emulsion, plays a dispersing role, which helps to evenly disperse the polymer particles in the entire floor coating. The aqueous mortar emulsion of the present invention uses polyol as the resin emulsion, which can be obtained by self-production or commercially available.

[0036] Active sand refers to sand that can improve the strength of mortar through chemical reaction or physical strengthening mechanism. Sand refers to granular materials obtained by natural or artificial methods, such as lime, silica, quartz sand, etc.

[0037] The adduct of the compound represented by formula I refers to the product obtained by polymerization of the compound represented by formula I itself or reaction of the compound represented by formula I with other compounds.

[0038] The waterborne polyurethane floor coating of the present invention comprises three components: an isocyanate composition, a waterborne mortar emulsion and an active sand material. The isocyanate group in the isocyanate composition reacts with a polyol hydroxyl group and water in the waterborne mortar emulsion to generate a polyurethane component and polyurea. The water in the waterborne mortar emulsion also undergoes a hydration reaction with cement in the active sand material, and finally the waterborne polyurethane floor coating is formed through the above reactions.

[0039] Among them, the isocyanate composition includes the compound shown in formula I and its adduct. On the one hand, compared with MDI having two benzene rings, the compound shown in formula I has only one benzene ring, the number of its benzene rings is smaller, and its NCO group is connected to the benzene ring through the L group, thereby avoiding the conjugation of the NCO group and the benzene ring. Therefore, the compound shown in formula I has a low degree of conjugation, which can reduce the absorption of ultraviolet rays by the floor coating, thereby avoiding the occurrence of yellowing, thereby improving its weather resistance; on the other hand, compared with aliphatic isocyanates and alicyclic isocyanates such as HDI and IPDI, the single benzene ring structure in the compound shown in formula I has a stronger electron donating effect, which is beneficial to enhancing the reactivity of the isocyanate group, so that it can be used without the addition of an additional catalyst. On the other hand, the compound shown in Formula I has a relatively low viscosity and functionality. The low viscosity makes the coating have better fluidity, making it easy to mix and participate in the reaction, but the low functionality leads to a low degree of crosslinking of the formed polyurethane, which is not conducive to improving the strength of the floor. The adduct of the compound shown in Formula I has a relatively high functionality and viscosity. The present invention obtains an isocyanate composition by mixing the compound shown in Formula I and its adduct, so that the isocyanate composition has both moderate viscosity and high functionality, so that the coating has a higher degree of crosslinking while maintaining good fluidity, so that the formed floor has a relatively high strength.

[0040] In summary, the present invention adds a polyisocyanate and a composition thereof with a specific structure into a water-based polyurethane floor coating, and synergizes the isocyanate composition, the water-based mortar emulsion and the active sand material according to the above-mentioned specific mass fractions, so that the floor coating has higher reactivity and fluidity, and the formed floor has higher mechanical strength and weather resistance.

[0041] In the specific scheme of the embodiment of the present application, the mass fraction of the isocyanate composition in the floor coating can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts or a range consisting of any two of the above values; the mass fraction of the aqueous mortar emulsion can be 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts or the range consisting of any two of the above values. Preferably, the mass fraction of the aqueous mortar emulsion is 8-16 parts; the mass fraction of the active sand can be 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, 75 parts, 76 parts, 77 parts, 78 parts, 79 parts, 80 parts or the range consisting of any two of the above values.

[0042] In some specific embodiments, the compound represented by Formula I is selected from one or more of the following compounds:

[0043]

[0044] The above isocyanate compounds can not only make the floor coating have higher reactivity, mechanical strength and weather resistance, but also have the advantages of wide sources and easy acquisition.

[0045] In some preferred embodiments, the adduct of the compound shown in Formula I includes an adduct of the compound shown in Formula I and trimethylolpropane (TMP) and / or a polymer of the compound shown in Formula I.

[0046] The multimer of the compound shown in Formula I refers to a polymer formed by at least two molecules of the compound shown in Formula I. For example, it can be a trimer, a pentamer, etc. of the compound shown in Formula I.

[0047] The compound shown in Formula I has 2 or 3 isocyanate groups, while TMP is a trifunctional polyol. The adduct formed by the reaction of the two has a highly cross-linked network structure, which is beneficial to improve the strength of floor coatings. Similarly, the polymer of the compound shown in Formula I can form a stronger network structure through cross-linking compared to the monomer, thereby improving the strength of the material.

[0048] In some preferred embodiments, the isocyanate composition comprises 70% to 99% of the compound of formula I and 1% to 29% of the adduct of the compound of formula I in terms of mass percentage.

[0049] Adding a suitable amount of its adduct to the component of formula I helps to improve the overall functionality of the isocyanate composition, thereby enhancing the crosslinking strength of the paint film, and improving the compressive strength, flexural strength and wear resistance of the paint film. The specific amount of addition can be selected within the above range according to different product performance requirements.

[0050] Exemplarily, the mass percentage of the compound represented by Formula I in the isocyanate composition can be 70%, 75%, 80%, 85%, 90%, 95%, 99% or a range consisting of any two of the above values, and the mass percentage of the adduct of the compound represented by Formula I can be 1%, 5%, 10%, 15%, 20%, 25%, 29% or a range consisting of any two of the above values.

[0051] In some preferred embodiments, the water content of the aqueous mortar emulsion is 10 wt% to 45 wt%, preferably 20 wt% to 40 wt%.

[0052] The water content of the water-based mortar emulsion within the above range is conducive to the formation of an oil-in-water structure of the coating system, thereby giving priority to the reaction between the polyol resin and the isocyanate in the early stage of the film-forming process of the coating system, thereby reducing the generation of bubbles.

[0053] Exemplarily, the water content of the aqueous mortar emulsion can be 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt% or a range consisting of any two of the above values.

[0054] The present invention does not specifically limit the source of the water-based mortar emulsion, which can be obtained by preparing the above compounds according to a specific mass percentage, or can be obtained commercially. For example, it can be one or more of the products with the brand names of allnex resin SETATHANE-DE-2761, allnex resin SETATHANE-DE-2767, and Solu Green, etc., or the above commercial water-based mortar emulsion can be mixed with water to meet a specific water content.

[0055] In some preferred embodiments, the floor coating further comprises a defoamer. The addition of the defoamer can inhibit the generation of bubbles during the use of the coating and avoid the adverse effect of bubbles on the floor strength.

[0056] Furthermore, the mass fraction of the defoamer in the floor coating is 0.1 to 1 part. For example, it can be 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1.0 part or a range consisting of any two of the above values.

[0057] The present invention does not specifically limit the type of the defoamer, which can be selected from defoamers commonly used in the art, such as BYK LP D 23014.

[0058] The present invention does not specifically limit the type of active sand material, as long as it is conducive to enhancing the strength of the floor, and specifically includes but is not limited to one or more of cement, slaked lime, and quartz sand. Among them, cement and quartz sand are conducive to enhancing the strength of the floor, and slaked lime can provide good plasticity and workability in the mortar, which is convenient for construction and leveling.

[0059] As a preferred embodiment, the active sand material includes 10 to 15 parts by mass of cement, 1 to 5 parts by mass of slaked lime and 50 to 60 parts by mass of quartz sand.

[0060] Furthermore, the active sand material may also include pigments for making the floor coating form different colors. Specifically, the pigments include one or more of titanium dioxide, phthalocyanine blue, and art green.

[0061] As a preferred embodiment, the quartz sand comprises a mixture of medium sand and fine sand, wherein the average particle size of the medium sand is 0.5-0.35 mm, and the average particle size of the fine sand is 0.35-0.25 mm. The mixture of medium sand and fine sand with different particle sizes can make the coating have better fluidity.

[0062] A second aspect of the present invention provides a method for preparing the waterborne polyurethane floor coating as described above, comprising the following steps:

[0063] The isocyanate composition is mixed with the water-based mortar emulsion, and then active sand is added and mixed to obtain a water-based polyurethane floor coating.

[0064] The present invention does not specifically limit the preparation method of the waterborne polyurethane floor coating, and the waterborne polyurethane floor coating can be efficiently and simply prepared through the above steps.

[0065] Furthermore, in order to ensure that the components are mixed evenly and react fully, the above mixing process can be completed by stirring at a rotation speed of 300 to 800 rpm. Exemplarily, the rotation speed can be 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm or a range consisting of any two of the above values.

[0066] The waterborne polyurethane floor coating and its preparation method provided by the present invention will be introduced in detail below in conjunction with specific embodiments.

[0067] In the following examples, unless otherwise specified, the raw materials used can be obtained by commercial purchase or conventional methods. Experimental methods without specific conditions are selected according to conventional methods and conditions in the art or according to the product instructions.

[0068] Among them, the sources of the main raw materials are as follows:

[0069] XDI: Wanhua Chemical Group Co., Ltd.

[0070] XDI-TMP: Wanhua Chemical Group Co., Ltd.

[0071] Phenyl diisocyanate: Wanhua Chemical Group Co., Ltd.

[0072] PM-200: Wanhua Chemical Group Co., Ltd.

[0073] HT-100: Wanhua Chemical Group Co., Ltd.

[0074] IPDI: Wanhua Chemical Group Co., Ltd.

[0075] Example 1

[0076] This embodiment provides a waterborne polyurethane floor coating and a preparation method thereof:

[0077] 1) The raw material formula of the waterborne polyurethane floor coating of this embodiment includes 15 parts of waterborne mortar emulsion, 14 parts of isocyanate composition, and 71 parts of active sand material according to the weight ratio;

[0078] The aqueous mortar emulsion includes 14.5 parts by weight of allnex resin SETATHANE-DE-2761 (water content is 30 wt%, resin content is 70 wt%) and 0.5 parts by weight of defoamer BYK-1794;

[0079] The isocyanate composition includes 11.9 parts by mass of the compound of formula I-2 and 2.1 parts by mass of the compound of formula I-2 and TMP adduct;

[0080] The active sand material includes 13.1 parts by mass of white cement, 3.5 parts by mass of slaked lime, and 54.1 parts by mass of quartz sand, wherein the quartz sand is a mixture of medium sand with a particle size of 0.5 to 0.35 mm and fine sand with a particle size of 0.35 to 0.25 mm in a mass ratio of 7:3.

[0081] 2) The preparation method of the waterborne polyurethane floor coating of this embodiment includes: mixing the waterborne mortar emulsion and the isocyanate composition evenly, adding active sand, and stirring at a speed of 500 rpm using a disperser to obtain the waterborne polyurethane floor coating.

[0082] Example 2

[0083] This embodiment provides a waterborne polyurethane floor coating and a preparation method thereof. The raw material formula and preparation method thereof are basically the same as those in Example 1, except that:

[0084] The raw material formula of the waterborne polyurethane floor coating includes, by weight: 16.4 parts of waterborne mortar emulsion, 15 parts of isocyanate composition, and 68.6 parts of active sand;

[0085] The water-based mortar emulsion includes 16 parts by mass of allnex resin SETATHANE-DE-2761 and 0.4 parts by mass of defoamer BYK-1794;

[0086] The isocyanate composition includes 10.5 parts by mass of the compound of formula I-2 and 4.5 parts by mass of the compound of formula I-2 and TMP adduct.

[0087] Example 3

[0088] This embodiment provides a waterborne polyurethane floor coating and a preparation method thereof. The raw material formula and preparation method thereof are basically the same as those in Example 1, except that:

[0089] The raw material formula of waterborne polyurethane floor coating includes, by weight: 10.5 parts of waterborne mortar emulsion, 10 parts of isocyanate composition, and 79.5 parts of active sand;

[0090] The water-based mortar emulsion includes 10 parts by mass of allnex resin SETATHANE-DE-2761 and 0.5 parts by mass of defoamer BYK LP D 23014D;

[0091] The isocyanate composition includes 9.5 parts by mass of the compound of formula I-2 and 0.5 parts by mass of a TMP adduct of the compound of formula I-2.

[0092] Example 4

[0093] This embodiment provides a waterborne polyurethane floor coating and a preparation method thereof. The raw material formula and preparation method thereof are basically the same as those in Example 1, except that:

[0094] The raw material formula of the waterborne polyurethane floor coating includes, by weight: 20.5 parts of waterborne mortar emulsion, 18 parts of isocyanate composition, and 61.5 parts of active sand;

[0095] The water-based mortar emulsion includes 20 parts by mass of allnex resin SETATHANE-DE-2761 and 0.5 parts by mass of defoamer BYK LP D 23014D;

[0096] The isocyanate composition includes 15.3 parts by mass of the compound of formula I-2 and 2.7 parts by mass of a TMP adduct of the compound of formula I-2.

[0097] Embodiments 5 to 9

[0098] Embodiments 5 to 9 provide a waterborne polyurethane floor coating and a preparation method thereof, wherein the raw material formula and the preparation method thereof are substantially the same as those of Embodiment 1, except that the type of the isocyanate composition is different from that of Embodiment 1, as follows:

[0099] The isocyanate composition of Example 5 includes 11.9 parts by mass of the compound of formula I-1 and 2.1 parts by mass of the TMP adduct of the compound of formula I-1;

[0100] The isocyanate composition of Example 6 includes 11.9 parts by mass of the compound of formula I-3 and 2.1 parts by mass of the TMP adduct of the compound of formula I-3;

[0101] The isocyanate composition of Example 7 includes 11.9 parts by mass of the compound of formula I-4 and 2.1 parts by mass of the TMP adduct of the compound of formula I-4.

[0102] The isocyanate composition of Example 8 includes 11.9 parts by mass of the compound of formula I-5 and 2.1 parts by mass of the TMP adduct of the compound of formula I-5.

[0103] The isocyanate composition of Example 9 includes 11.9 parts by mass of the compound of formula I-2 and 2.1 parts by mass of the trimer of the compound of formula I-2.

[0104] Example 10

[0105] Example 10 provides a waterborne polyurethane floor coating and a preparation method thereof, wherein the raw material formula and preparation method thereof are substantially the same as those of Example 1, except that:

[0106] The isocyanate composition of Example 10 includes 9.3 parts by mass of Formula I-2 and 4.67 parts by mass of the TMP adduct of Formula I-2.

[0107] Examples 11 to 14

[0108] Embodiments 11 to 14 provide a waterborne polyurethane floor coating and a preparation method thereof, wherein the raw material formula and preparation method thereof are substantially the same as those of Embodiment 1, except that the composition of the waterborne mortar emulsion is different from that of Embodiment 1, as follows:

[0109] The aqueous mortar emulsion of Example 11 includes 14.5 parts by mass of allnex resin SETATHANE-DE-2767 and 0.5 parts by mass of defoamer BYK-1794, wherein the water content of allnex resin SETATHANE-DE-2767 is 10 wt % and the resin content is 90 wt %;

[0110] The composition of the water-based mortar emulsion of Example 12 is substantially the same as that of Example 11, except that the allnex resin SETATHANE-DE-2767 is added to adjust the water content to 20 wt %;

[0111] The composition of the water-based mortar emulsion of Example 13 is substantially the same as that of Example 11, except that the allnex resin SETATHANE-DE-2767 is added to adjust the water content to 30 wt %;

[0112] The composition of the aqueous mortar emulsion of Example 14 is substantially the same as that of Example 11, except that the allnex resin SETATHANE-DE-2767 is added to adjust the water content to 50 wt %.

[0113] Embodiments 15-16

[0114] Embodiments 15 to 16 provide a waterborne polyurethane floor coating and a preparation method thereof, wherein the raw material formula and preparation method thereof are substantially the same as those of Embodiment 1, except that:

[0115] The quartz sand in Example 15 only uses medium sand with a particle size of 0.5 to 0.35 mm;

[0116] The quartz sand used in Example 16 is only fine sand with a particle size of 0.35 to 0.25 mm.

[0117] Comparative Examples 1 to 4

[0118] Comparative Examples 1 to 4 provide a waterborne polyurethane floor coating and a preparation method thereof, wherein the raw material formula and preparation method thereof are substantially the same as those of Example 1, except that:

[0119] Comparative Example 1: The isocyanate composition in Example 1 was replaced with PM200;

[0120] Comparative Example 2: The isocyanate composition in Example 1 is replaced with HDI trimer HT100;

[0121] Comparative Example 3: The isocyanate composition in Example 1 is replaced by the compound shown in Formula I-2;

[0122] In Comparative Example 4, the isocyanate composition of Example 1 was replaced with isophenylene diisocyanate.

[0123] Test Case

[0124] According to the national standard "GB / T 22374-2018 Floor Coating Materials", the waterborne polyurethane floor coatings of the above embodiments and comparative examples were tested for initial fluidity, operable time, wear resistance, compressive strength (7d), flexural strength (7d), water resistance (168 hours), acid resistance (10% sulfuric acid, 48h), and oil resistance (120# solvent oil, 72h). Among them, the wear resistance test standard uses a 1000-turn, CS-17 rubber grinding wheel for testing;

[0125] Artificial aging resistance is tested by artificial accelerated aging test according to GB / T 23987-2009. The conductivity of the spray water is ≤5μS / cm; the cycle conditions are: UV radiation for 8h, 0.77W / m 2 , 60℃; dark for 4h, 50℃; condensation for 4h, 40℃; spraying for 15min. The rating method uses GB-T 1766-2008 rating method for paint and varnish coating aging.

[0126] The test results of the above parameters are shown in Table 1. In Table 1, normal appearance indicates that the appearance is normal and no bubbles are generated; normal water resistance, acid resistance and oil resistance indicate that the appearance of the coating does not change during the water resistance, acid resistance and oil resistance tests, indicating that the water resistance, acid resistance and oil resistance are good; the higher the value of artificial aging resistance, the higher the degree of yellowing of the coating and the worse the weather resistance.

[0127] Table 1

[0128]

[0129]

[0130] From Table 1 we can see that:

[0131] 1) Examples 1 to 4 all have excellent appearance, construction performance, mechanical strength and yellowing resistance, and can meet various requirements for outdoor floors.

[0132] 2) The floor coatings of Examples 1 and 5 to 9 have good yellowing resistance and weather resistance. It can be seen that different types of isocyanate compounds such as Formula I-1, Formula I-2, Formula I-3, Formula I-4, and Formula I-5 are used in floor coatings, and the performance is similar; the viscosity of the compounds of Formula I-4 and Formula I-5 used in Examples 7 to 8 is relatively large, resulting in a higher viscosity of the system and poor overall fluidity of the paint film; compared with Examples 1 and 5 to 8 using a combination of isocyanate and TMP compounded with isocyanate, Example 9 uses a trimer of XDI compounded with an isocyanate compound, and the coating performance of the two cases is similar, and the performance is relatively balanced.

[0133] 3) By comparing Example 1 with Example 10, it can be seen that the adduct ratio in Example 10 is increased, resulting in an increase in the viscosity of the system and a decrease in the initial fluidity of the paint film.

[0134] 4) By comparing Examples 11 to 14, it can be seen that the content of the water-based mortar emulsion has an effect on the viscosity and strength of the coating. The less the water content of the water-based mortar emulsion, the worse the fluidity of the paint film. At the same time, a lower water content will also lead to insufficient reaction of cement in the sand, resulting in a decrease in the strength of the paint film. Too much water content will lead to too many side reactions, resulting in blistering on the appearance of the paint film, and a significant decrease in compressive strength and flexural strength. The water content of the water-based mortar emulsion in Example 13 is the most suitable, and the overall performance is the best.

[0135] 5) By comparing Example 1 and Examples 15 to 16, it can be seen that the combined quartz sand material obtained by compounding medium sand and fine sand can make the paint film have better fluidity.

[0136] 6) By comparing Example 1 with Comparative Examples 1 to 4, it can be seen that Comparative Example 1 uses MDI as the isocyanate component, which has better physical strength but poor yellowing resistance; Comparative Examples 2 to 3 use HDI trimer, which has a slow reaction rate and low strength, and it is difficult to meet the strength requirements of floor coatings; Comparative Example 4 only uses a single compound shown in Formula I-2. Although it has good fluidity, the paint film strength is not as good as that of Example 1 in which an adduct is added; Comparative Example 5 uses isophenylene diisocyanate, which has a structure similar to the compound shown in Formula I-2. Although it also has only one phenyl group, the isocyanate group and the benzene ring are directly conjugated, resulting in poor yellowing resistance of its paint film.

[0137] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some or all of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A waterborne polyurethane floor coating, characterized in that: The floor coating comprises the following components in parts by mass: 10 to 20 parts of isocyanate composition; 8-22 parts of water-based mortar emulsion; 60-80 parts of active sand; The isocyanate composition comprises a compound shown in formula I and an adduct thereof: In formula I, R is phenyl or substituted phenyl, the substituent in the substituted phenyl is selected from C1-C6 alkyl, C1-C6 alkoxy or halogen; L is -CH2-, -CH2CH2- or -C(CH3)2-; n is 2 or 3.

2. The waterborne polyurethane floor coating according to claim 1, characterized in that: The compound represented by formula I is selected from one or more of the following compounds:

3. The waterborne polyurethane floor coating according to claim 1 or 2, characterized in that: The adduct of the compound shown in formula I includes an adduct of the compound shown in formula I and trimethylolpropane and / or a polymer of the compound shown in formula I.

4. The waterborne polyurethane floor coating according to any one of claims 1 to 3, characterized in that: The isocyanate composition comprises 70% to 99% of the compound shown in formula I and 1% to 29% of the adduct of the compound shown in formula I in terms of mass percentage.

5. The waterborne polyurethane floor coating according to claim 1, characterized in that: The water content of the aqueous mortar emulsion is 10 wt% to 45 wt%, preferably 20 wt% to 40 wt%.

6. The waterborne polyurethane floor coating according to claim 1 or 5, characterized in that: The aqueous mortar emulsion includes a defoamer.

7. The waterborne polyurethane floor coating according to claim 1, characterized in that: The active sand material includes one or more of cement, slaked lime and quartz sand.

8. The waterborne polyurethane floor coating according to claim 7, characterized in that: The active sand material comprises 10 to 15 parts by mass of cement, 1 to 5 parts by mass of slaked lime and 50 to 60 parts by mass of quartz sand.

9. The waterborne polyurethane floor coating according to claim 7 or 8, characterized in that: The quartz sand comprises a mixture of medium sand and fine sand; the average particle size of the medium sand is 0.5 mm to 0.35 mm; the average particle size of the fine sand is 0.35 mm to 0.25 mm.

10. A method for preparing the waterborne polyurethane floor coating according to any one of claims 1 to 9, characterized in that: The following steps are involved: The isocyanate composition is mixed with the aqueous mortar emulsion, and then the active sand material is added and mixed to obtain the aqueous polyurethane floor coating.

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