UV photocuring polyurea sealant and preparation method thereof

Abstract

The invention discloses a UV light-cured polyurea sealant and a preparation method thereof. The UV light-cured polyurea sealant is prepared from a polyurea acrylate prepolymer, a reactive diluent, a photoinitiator, a defoaming agent, a dispersing agent and filler. Wherein the Mn of the polyurea acrylate prepolymer is 6000 to 8000, the Mw of the polyurea acrylate prepolymer is 7500 to 9500, the Tg of the polyurea acrylate prepolymer is-40 DEG C to-20 DEG C, and the double bond content of the polyurea acrylate prepolymer is 1.0 to 1.5 mmol / g. According to the present invention, the prepared UV light-cured polyurea seam beautifying agent can achieve rapid light curing so as to achieve the purpose of convenient construction, can achieve excellent mechanical properties such as high strength, high hardness, high toughness, high adhesion and impact resistance, has stable and lasting hydrophobic and waterproof ability, and can be suitable for tile seam filling in humid environments such as kitchens, bathrooms and the like; in addition, the wide requirement from matte to highlight can be met; in addition, the preparation method is simple, and large-scale production is easy to realize.

Description

Technical Field

[0001] This invention relates to a tile grout product and its preparation method, specifically to a UV-curable polyurea tile grout and its preparation method, belonging to the field of functional materials technology. Background Technology

[0002] With the improvement of people's living standards and the increasing demand for aesthetically pleasing living environments, tile tiling has become a common choice for interior and exterior decoration. As a key material for filling tile gaps and beautifying decorative spaces, the performance of grout directly affects the overall decoration effect and durability.

[0003] Currently, the market for epoxy grout products has undergone iterative development from white cement and single-component water-based epoxy resin to two-component epoxy resin and two-component polyurea grout. Two-component epoxy resin grout, due to its high hardness and rich colors, once became the mainstream in the market, but it also has some inherent drawbacks: First, its curing reaction speed is greatly affected by ambient temperature; it cures slowly at low temperatures and reacts too quickly at high temperatures, causing inconvenience during construction. Second, epoxy resin is prone to yellowing under long-term ultraviolet radiation, affecting its appearance, especially in sunny areas such as outdoors or balconies. Third, its curing process involves a certain degree of volume shrinkage, which may lead to microcracks or detachment at the bonding point with the tiles. Finally, the product usually contains a certain amount of organic solvents and volatile amine curing agents, posing environmental and health risks.

[0004] To address the yellowing problem of epoxy resin, polyurea grout sealant has emerged in recent years. Polyurea materials possess excellent resistance to yellowing, high elasticity, abrasion resistance, and chemical corrosion resistance, far surpassing the performance of epoxy resin. However, existing two-component polyurea grout sealants typically use amines or isocyanates as curing agents, requiring precise mixing of components A and B before application. This introduces new problems: ① Short working window: After mixing, the curing reaction begins rapidly, and applicators must complete the application within a limited working time; otherwise, the material thickens and hardens, leading to application difficulties and material waste; ② High requirement for mixing uniformity: Insufficient mixing of components A and B can result in localized uncured areas or decreased performance, demanding high application skills; ③ Residue issues: Unreacted isocyanate components may be harmful to human health.

[0005] Ultraviolet (UV) light curing technology originated in the 1960s. Its basic principle is that when a liquid matrix containing unsaturated carbon-carbon double bonds is irradiated with ultraviolet light, the photoinitiator absorbs the radiation energy and is excited, generating free radicals or cations. This, in turn, triggers a chemical reaction between the unsaturated carbon-carbon double bonds in the liquid matrix, resulting in cross-linking and curing to form a cured product with a three-dimensional structure. UV light curing technology has significant advantages such as fast curing speed, high energy efficiency, zero volatile organic compound (VOC) emissions, insensitivity to temperature, and the ability to achieve automated production. It has been widely used in coatings, inks, adhesives, and other fields.

[0006] Introducing UV curing technology into the tile grout industry holds promise for completely resolving numerous shortcomings of existing two-component polyurea tile grout products, such as short operating windows, uneven mixing, and dependence on ambient temperature. However, directly using traditional UV-cured resins (such as epoxy acrylates and polyurethane acrylates) presents problems including insufficient adhesion to tiles, high hardness but poor toughness after curing, large shrinkage, and inadequate aging resistance to fully meet the long-term use requirements of tile grout. Therefore, there is an urgent need in this field to develop a new type of tile grout that retains the excellent properties of polyurea materials, such as resistance to yellowing and high elasticity, while also combining the advantages of UV curing technology, such as high efficiency, environmental friendliness, and convenient application. Summary of the Invention

[0007] In view of the above-mentioned problems and needs of the existing technology, the purpose of this invention is to provide a UV-curable polyurea grout sealant and its preparation method.

[0008] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0009] A UV-curable polyurea grout sealant is made using the following formula:

[0010] 30-60 parts by weight of polyurea acrylate prepolymer;

[0011] 30-60 parts by weight of reactive diluent;

[0012] 1-5 parts by weight of photoinitiator;

[0013] Defoamer 0.1-0.5 parts by weight;

[0014] Dispersant 0.2–1 parts by weight;

[0015] 10-30 parts by weight of filler;

[0016] The polyurea acrylate prepolymer has a number-average molecular weight (Mn) of 6000–8000, a weight-average molecular weight (Mw) of 7500–9500, a glass transition temperature (Tg) of -40℃ to -20℃, and a double bond (C=C) content of 1.0–1.5 mmol / g.

[0017] In a preferred embodiment, the polyurea acrylate prepolymer has a number-average molecular weight (Mn) of 6200–7500, a weight-average molecular weight (Mw) of 7800–9300, a glass transition temperature (Tg) of -35℃ to -23℃, and a double bond (C=C) content of 1.2–1.45 mmol / g.

[0018] In a further preferred embodiment, the molecular weight distribution index (PDI=Mw / Mn) of the polyurea acrylate prepolymer is 1.2 to 1.3.

[0019] In a further preferred embodiment, the viscosity of the polyurea acrylate prepolymer at 25°C is 4500–6500 mPa·s.

[0020] In a further preferred embodiment, the acid value of the polyurea acrylate prepolymer is ≤ 0.1 mg KOH / g.

[0021] In one embodiment, the polyurea acrylate prepolymer is made from the following raw materials:

[0022] 4-6 parts by weight of isocyanate;

[0023] 30-50 parts by weight of polyetheramine;

[0024] Hard monomer 0.05-0.5 parts by weight;

[0025] Soft monomer 0.05-0.5 parts by weight;

[0026] Functional monomers, 0.05–0.5 parts by weight;

[0027] Catalyst: 0.1–0.3 parts by weight;

[0028] Polymerization inhibitor: 0.1–0.3 parts by weight;

[0029] Solvent 20-30 parts by weight.

[0030] In one embodiment, the isocyanate is selected from any one of isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), diphenylmethane diisocyanate (MDI), and toluene diisocyanate (TDI), with isophorone diisocyanate (IPDI) being preferred.

[0031] In one embodiment, the polyetheramine is selected from any one of D230, D400, and D2000, with D2000 being preferred.

[0032] In one embodiment, the hard monomer is selected from methyl methacrylate (MMA) and / or methyl acrylate (MA); the soft monomer is selected from any one or more of ethyl acrylate (EA), n-butyl acrylate (n-BA), lauryl acrylate (LA), 2-ethylhexyl acrylate (2-HEA), and lauryl methacrylate (LMA); and the functional monomer is selected from any one or more of hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), acrylamide, and hydroxypropyl methacrylate (HPMA).

[0033] In a preferred embodiment, the hard monomer is selected as methyl methacrylate (MMA), the soft monomer is selected as 2-ethylhexyl acrylate (2-HEA), and the functional monomer is selected as hydroxyethyl acrylate (HEA).

[0034] In a further preferred embodiment, the mass ratio of the hard monomer to the soft monomer to the functional monomer is 35:35:30.

[0035] In one embodiment, the catalyst is selected from either dibutyltin dilaurate (DBTDL) or dibutyltin dioctanoate (DBTO), with dibutyltin dilaurate (DBTDL) being preferred.

[0036] In one embodiment, the polymerization inhibitor is selected from any one of hydroquinone (HQ), p-hydroxyanisole (MEHQ), 2,6-di-tert-butyl-p-cresol (BHT), and methyl hydroquinone (THQ), with hydroquinone (HQ) being the most preferred.

[0037] In one embodiment, the solvent is selected from any one of acetone, ethyl acetate, toluene, dibutyl phthalate (DBP), and dioctyl phthalate (DOP), with acetone being the preferred choice.

[0038] In one embodiment, the preparation of the polyurea acrylate prepolymer includes the following steps:

[0039] S1) Under nitrogen protection, first add the required amount of isocyanate and solvent to the reaction vessel, then heat it to 50-60°C in a water bath, and add the required amount of polyetheramine dropwise while stirring, controlling the dropwise rate so that the internal temperature does not exceed 60°C.

[0040] After S2) is finished, maintain the internal temperature at 50-60℃ to continue the reaction; when the content of the remaining isocyanate group (-NCO) is monitored to be 5wt%-10wt%, raise the internal temperature to 55-65℃, and add a mixture of functional monomer and about 1 / 3 catalyst in the specified amount while stirring.

[0041] After S3) drops are completed, maintain the internal temperature at 55-65℃ to continue the reaction; when the content of the remaining isocyanate group (-NCO) is monitored to be 0.5wt%-2wt%, add a mixture of the specified amount of soft monomer and about 1 / 3 of the specified amount of catalyst dropwise under stirring.

[0042] After S4) the reaction is completed, maintain the internal temperature at 55-65℃ and continue the reaction; when the residual -NCO content is monitored to be 0.05wt%-0.2wt%, add a mixture of the specified amount of hard monomer and the remaining amount of catalyst dropwise while stirring.

[0043] After S5) the reaction is completed, the internal temperature is maintained at 55-65℃ to continue the reaction; when the content of residual isocyanate group (-NCO) is ≤0.01wt%, the trace amount of by-product low-boiling substances is removed by vacuum to obtain acrylate-terminated polyurea macromonomer.

[0044] S6) Reduce the temperature of the reaction system to 50-60℃, add the specified amount of polymerization inhibitor, and keep the system warm and stir until the system is uniform and transparent.

[0045] S7) Turn off the nitrogen gas, stop stirring, allow it to cool naturally to room temperature, and filter to obtain a colorless to slightly yellow liquid polyurea acrylate prepolymer.

[0046] In a preferred embodiment, the polyetheramine, hard monomer, soft monomer, and functional monomer are all pre-treated by vacuum dehydration at 60-80°C until the moisture content is ≤0.05%.

[0047] In a preferred embodiment, the stirring rate is 150–250 rpm / min.

[0048] In one embodiment, the reactive diluent is selected from any one or two of tripropylene glycol diacrylate (TPGDA), trimethylolpropane triacrylate (TMPTA), 1,6-hexanediol diacrylate (HDDA), and isobornyl acrylate (IBOA).

[0049] In a preferred embodiment, the reactive diluent is composed of tripropylene glycol diacrylate (TPGDA) and 1,6-hexanediol diacrylate (HDDA) in a mass ratio of 1:1.

[0050] In one embodiment, the photoinitiator is selected from any one or two of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I2959), 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (819).

[0051] In a preferred embodiment, the photoinitiator is composed of I2959 and 1173 in a mass ratio of 1:1 to 1:9.

[0052] In one embodiment, the defoamer is selected from any one of BASF 2410AC, BYK-A530, and BYK-014, with BASF 2410AC being preferred.

[0053] In one embodiment, the dispersant is selected from any one of BYK-110, BYK-2152, and BYK-AT204, with BYK-110 being preferred.

[0054] In one embodiment, the filler is selected from any one or more of fumed silica, calcium carbonate, barium sulfate, quartz, alumina, and hydrotalcite.

[0055] In a preferred embodiment, the filler is composed of fumed silica and quartz in a mass ratio of 1:19 to 1:20.

[0056] One embodiment of the UV-cured polyurea grout preparation method includes the following steps:

[0057] a) Under yellow light, add the solid photoinitiator in the formula to 1 / 12 to 1 / 6 of the amount of reactive diluent, and heat in a water bath at 80 to 100°C until it is completely dissolved to obtain solution A, which is then set aside.

[0058] b) Add the specified amount of polyurea acrylate prepolymer, the remaining specified amount of reactive diluent, the liquid photoinitiator, defoamer, and dispersant from the formulation to the mixing tank, and stir at 800–1000 rpm until they are uniformly mixed; then add the specified amount of filler, and stir at 1000–2000 rpm until they are uniformly mixed.

[0059] c) Add solution A to the mixture obtained in step b) and stir at 800-1000 rpm until it is uniformly mixed to obtain the UV-curable polyurea grout, which is a uniformly dispersed and opaque liquid product.

[0060] Compared with the prior art, the present invention has the following significant advantages:

[0061] Experiments have shown that this invention, by employing a specific polyurea acrylate prepolymer, not only enables the prepared UV-curable polyurea grout to achieve rapid curing (only 0.5 minutes), facilitating convenient construction, but also achieves excellent mechanical properties such as high strength, high hardness, high toughness, high adhesion, and impact resistance. Furthermore, it possesses stable and durable hydrophobic and waterproof capabilities, making it suitable for tile grouting in damp environments such as kitchens and bathrooms. In addition, the gloss level can be flexibly adjusted within the range of 55.7 to 79.8, meeting a wide range of needs from matte to high gloss. Moreover, the preparation method of the UV-curable polyurea grout described in this invention is simple, easy to scale up, and exhibits good process stability. Therefore, this invention successfully solves the contradiction between curing speed, mechanical balance, durability, and decorative effect that is difficult to balance in traditional grout products, demonstrating significant progress and application value compared to existing grout products. Attached Figure Description

[0062] Figure 1 The infrared spectra of the polyurea acrylate prepolymer and the UV-cured polyurea grout sealant in Example 1 are compared before and after curing.

[0063] Figure 2 Photographs showing the water resistance test results of UV-cured polyurea grout prepared in Examples 1-7. Detailed Implementation

[0064] The technical solution of the present invention will be further described in detail and completely below with reference to the embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the manufacturer.

[0065] The performance testing methods for polyurea acrylate prepolymers in the following examples and comparative examples are described below:

[0066] ① Molecular weight and molecular weight distribution: Gel permeation chromatography (GPC) was used with tetrahydrofuran as the mobile phase and polystyrene as the standard to determine the number average molecular weight (Mn) and weight average molecular weight (Mw), and the molecular weight distribution index was calculated according to PDI=Mw / Mn.

[0067] ② Glass transition temperature (Tg): Determined by differential scanning calorimetry (DSC) at a heating rate of 10℃ / min;

[0068] ③ Double bond content: determined by iodometric titration or 1H NMR, unit mmol / g;

[0069] ④ Isocyanate (-NCO) content: According to standard GB / T 12009.4-2016, the di-n-butylamine-hydrochloric acid titration method was used for determination, and the detection limit was 0.01wt%.

[0070] ⑤ Viscosity: Measured using a rotational viscometer at 25℃, unit: mPa·s;

[0071] ⑥ Acid value: Determined by acid-base titration method according to standard GB / T 2895-2008, expressed as mg KOH / g.

[0072] The test methods for the mechanical properties and stability of UV-cured polyurea grout in the following examples and comparative examples are as follows:

[0073] ① Tensile property test

[0074] Referencing GB / T 328.9 "Test Methods for Waterproofing Membranes - Part 9: Tensile Properties of Polymer Waterproofing Membranes" or GB / T 18173.1 "Polymer Waterproofing Materials - Part 1: Sheets", the tensile test methods applicable to elastomers are used. A universal testing machine is used to stretch a standard dumbbell-shaped specimen (cut according to specifications) at a constant rate to determine its tensile strength (maximum stress at fracture) and elongation at break (percentage of elongation at fracture to initial length).

[0075] ② Hardness test

[0076] Referring to the standards GB / T 6739-2022 "Determination of Hardness of Pencils" and ISO 15184:2020 "Determination of Hardness of Pencils with Paints and Varnishes", the specific test method is as follows:

[0077] Prepare high-quality drawing pencils that meet relevant standards, such as 6H, 5H, 4H, 3H, 2H, H, F, HB, etc. Use a pencil sharpener to remove the wood from the pencil, exposing about 5mm of lead, and ensure that the lead is an undamaged cylindrical shape.

[0078] Ensure the sample is flat, free of oil and damage, and place it in an environment of 23±2 ℃ for at least 24 hours before testing;

[0079] Fix the pencil on the pencil hardness tester, make the pencil at a 45-degree angle to the sample surface (with the pencil tip away from the operator), and then draw a line of about 15mm away from the operator.

[0080] Start with the hardest pencil and gradually decrease the hardness of the pencils you use until the pencil cuts into or scratches the coating.

[0081] Result determination: The pencil hardness of the UV-cured polyurea grout is determined by the pencil hardness that does not scratch or abrade the coating; for example, if a 6H pencil does not scratch the coating, but a 5H pencil does scratch the coating, then the pencil hardness of the grout is 6H.

[0082] ③ Flexibility test

[0083] The test was conducted in accordance with the provisions of standard GB / T 1731-2020. The wet film thickness should be 1.0±0.1 mm. The test was conducted after curing under standard conditions for 168 hours. The specific test method is as follows: The grout to be tested was applied to a clean tinplate (120mm×25mm×0.3mm), and the wet film thickness was controlled at 1.0±0.1 mm. After complete curing under UV light, it was placed under standard conditions of 23±2 ℃ and 50±5 % relative humidity for 168 hours. After curing, the test plate was bent 180° around a standard axis bar with the coating facing outward within 2-3 seconds. The plate was immediately observed with a 4x magnifying glass. The smallest axis bar diameter (mm) that did not cause the paint film to crack or peel off was recorded as the flexibility result. The smaller the result value, the better the flexibility.

[0084] ④ Impact resistance test

[0085] Referring to the standard GB / T 1732-2020 "Test Method for Impact Resistance of Coating Film", the grout was applied to a standard substrate and cured until the coating was fully cured. The grout side of the test panel was placed face up on the anvil of the impact tester, ensuring that there was solid support below the impact point. Avoiding the edges, a 1kg impact hammer was released and allowed to fall freely, impacting the predetermined point vertically. Immediately afterward, the grout coating in the impact point and surrounding area was observed with a 4x magnifying glass to check for cracks or peeling. The impact was repeated at least 3 times at different positions on the same test panel or on a parallel sample. If no cracks or peeling occurred at any impact point at a certain height, it was judged as "passing the XX cm·kg impact resistance test". The ultimate impact resistance value was determined by increasing the impact height or the weight of the impact hammer until the sample was destroyed.

[0086] ⑤ Adhesion performance test

[0087] Referring to standards such as GB / T 9286-2021, ISO 2409, and ASTM D 3359, the grout is applied to a standard substrate. During testing, six parallel cuts are made on the coating using a cross-cutting tool, followed by six vertical cuts to form many small squares. For soft substrates, the grading is determined after cleaning with a soft brush; for hard substrates, after cleaning, tape is applied, quickly pulled off, and the grading is compared with the standard attached diagram.

[0088] ⑥ Contact angle performance test

[0089] The contact angle was measured using a contact angle tester, referring to the contact angle test method in standard T / CECS 10158-2021 "Aspartic Polyurea Tile Grout".

[0090] ⑦ Water absorption performance test

[0091] Referring to the water absorption test method in the standard T / CECS 10158-2021 "Aspartic Polyurea Tile Grout", after preparing a sample of regular size and uniformity, soak it in water for 24 hours, then use filter paper to absorb the surface moisture, weigh it immediately, and calculate the water absorption rate.

[0092] ⑧ Water resistance test

[0093] According to the reference standard GB / T 1733-1993 "Test Method for Water Resistance of Paint Film": After the sample is applied to the tile and cured, it is immersed in water, with two-thirds of the surface area immersed. After immersion for 24 hours, it is taken out, the surface moisture is dried, and the surface is visually inspected for phenomena such as loss of gloss, discoloration, and blistering. If it meets the product technical specifications, the water resistance of the grout is deemed qualified.

[0094] 9. Gloss Test

[0095] Referring to standard GB / T 9754, apply the grout sealant to the tile surface to form a smooth, bubble-free coating, and allow it to cure completely. Before testing, gently clean the surface dust with a soft cloth. Turn on the gloss meter and preheat it to a stable temperature. Place the gloss meter on a high-gloss work plate and adjust the reading to the standard plate calibration value. Then place it on a low-gloss plate (or zero calibration box) to check the zero point, ensuring the instrument is within its valid calibration period. Set the measurement angle to 60° and ensure the gloss meter's measuring port is tightly and vertically attached to the smooth surface of the grout sealant coating, ensuring no gaps and avoiding external light interference. Select at least 3-5 different locations on the sample for measurement and record the gloss value (in GU, gloss unit) at each point. Calculate the average value of all measurement points as the final gloss result for the sample.

[0096] Example 1

[0097] I. Preparation of polyurea acrylate prepolymer

[0098] This embodiment uses the following formulation to prepare the polyurea acrylate prepolymer:

[0099] Isocyanate (IPDI selected) 4.58g;

[0100] Polyetheramine (D2000 selected) 40.00g;

[0101] Hard monomer (selected MMA) 0.091g;

[0102] Soft monomer (using 2-HEA) 0.091g;

[0103] Functional monomer (HEA selected) 0.078g;

[0104] Catalyst (DBTDL selected) 0.15g;

[0105] Polymerization inhibitor (HQ selected) 0.20g;

[0106] Solvent (acetone preferred) 24.00g.

[0107] First, place the above-mentioned polyetheramine, hard monomer, soft monomer and functional monomer into a vacuum drying oven, and dehydrate them at 60-80℃ until the moisture content is ≤0.05%. Then cool them down to below 40℃ for later use.

[0108] The specific preparation method of the polyurea acrylate prepolymer is as follows:

[0109] S1) Under nitrogen protection, the required amount of isocyanate (4.58g IPDI in this example) and solvent (24.00g acetone in this example) are first added to the reaction vessel. Then, the vessel is heated to 50°C in a water bath. While stirring, the required amount of polyetheramine (40.00g D2000 in this example) is added dropwise, with the dropping rate controlled to keep the internal temperature below 60°C.

[0110] After S2) the addition is complete, maintain the internal temperature at 50°C and continue the reaction. Take samples every 30 minutes and use online FTIR to track the -NCO characteristic peak (2242 cm-1) to monitor the isocyanate group (-NCO) content. When the remaining -NCO content is in the range of 5wt% to 10wt% (inclusive of the endpoint value), verify it according to the di-n-butylamine-hydrochloric acid titration method in standard GB / T 12009.4-2016. When the verified remaining -NCO content is in the range of 5wt% to 10wt% (inclusive of the endpoint value), raise the internal temperature to 60°C and add a mixture of functional monomer (0.078 g HEA in this example) and about 1 / 3 of the catalyst (0.05 g DBTDL in this example) dropwise while stirring.

[0111] After S3) the addition is complete, maintain the internal temperature at 60°C and continue the reaction; when the content of the remaining -NCO is monitored by di-n-butylamine-hydrochloric acid titration method and is in the range of 0.5wt% to 2wt% (including the endpoint value), add dropwise a mixture of the specified amount of soft monomer (0.091g 2-HEA in this example) and about 1 / 3 of the specified amount of catalyst (0.05g DBTDL in this example) under stirring.

[0112] After S4) the addition is complete, maintain the internal temperature at 60°C and continue the reaction; when the residual -NCO content is monitored by di-n-butylamine-hydrochloric acid titration method and is in the range of 0.05wt% to 0.2wt% (including the endpoint value), add dropwise a mixture of the specified amount of hard monomer (0.091g MMA in this example) and the remaining specified amount of catalyst (0.05g DBTDL in this example) under stirring.

[0113] After S5) the titration is complete, maintain the internal temperature at 60℃ to continue the reaction; when the residual -NCO content is ≤0.01wt% by the di-n-butylamine-hydrochloric acid titration method, remove the trace amount of by-product low-boiling substances under vacuum to obtain acrylate-terminated polyurea macromonomers.

[0114] S6) Reduce the temperature of the reaction system to 50°C, add the specified amount of polymerization inhibitor (0.20g HQ in this example), and keep the temperature and stir until the system is uniform and transparent;

[0115] S7) Turn off the nitrogen gas, stop stirring, and allow it to cool naturally to room temperature. Filter through a 0.2 µm PTFE filter to obtain a colorless to slightly yellow liquid polyurea acrylate prepolymer, abbreviated as P1.

[0116] The number-average molecular weight (Mn), weight-average molecular weight (Mw), glass transition temperature (Tg), double bond content, viscosity, and acid value of the obtained polyurea acrylate prepolymer were tested according to the above test method. The test results are shown in Table 1.

[0117] II. Preparation of UV-cured polyurea grout

[0118] This embodiment uses the following formula to prepare UV-curable polyurea grout sealant:

[0119] 40.0g of polyurea acrylate prepolymer;

[0120] Reactive diluent (TPGDA:HDDA=1:1) 60.0g;

[0121] Photoinitiator (I2959, solid) 0.5g;

[0122] Photoinitiator (1173, liquid) 4.5g;

[0123] Defoamer (BASF 2410AC) 0.3g;

[0124] Dispersant (BYK-110) 0.5g;

[0125] Filler (fumed silica) 1.0g;

[0126] Filler (quartz powder) 20.0g.

[0127] The specific preparation method of the UV-curable polyurea joint sealant is as follows:

[0128] a) Under a yellow light environment, add the solid photoinitiator in the formula (0.5 g of I2959 photoinitiator in this example) to 1 / 12 - 1 / 6 of the proportion amount of the reactive diluent (5 g of reactive diluent HDDA in this example), heat it in a water bath at 90 °C until it is completely dissolved, and obtain Solution A for standby;

[0129] b) Add the proportion amount of the polyurea acrylate prepolymer (40.0 g of polyurea acrylate prepolymer P1 in this example), the remaining proportion amount of the reactive diluent (25 g of reactive diluent HDDA and 30 g of TPGDA in this example), the liquid photoinitiator in the formula (4.5 g of 1173 photoinitiator in this example), the defoaming agent (0.3 g of BASF 2410AC in this example), and the dispersant (0.5 g of BYK - 110 in this example) into the feed barrel, stir at 800 rpm until they are mixed evenly (about stir for 5 min); then add the proportion amount of the filler (1 g of fumed silica and 20 g of quartz powder in this example), and stir at 1000 rpm until they are mixed evenly (about stir for 30 min);

[0130] c) Add Solution A to the mixed system obtained in step b), stir at 800 rpm until they are mixed evenly (about stir for 5 min), and the obtained UV-curable polyurea joint sealant is a uniformly dispersed and opaque liquid product.

[0131] Figure 1 is the infrared spectrum comparison chart of the polyurea acrylate prepolymer prepared in this example and the UV-curable polyurea joint sealant before and after curing; as Figure 1 shown: The integral areas of the absorption peaks of the polyurea acrylate prepolymer at 2242 cm -1 (N=C=O) and 3423 cm -1 (-OH) are both 0, indicating that the N=C=O bond of IPDI and the -OH bond of HEA have reacted completely without remaining groups; and, the C=C stretching vibration peak of the polyurea acrylate prepolymer at 1720 cm -1 weakens, which indicates that the double bond of the acrylate still exists, forming the polyurea acrylate prepolymer; in addition, after the UV-curable polyurea joint sealant is UV-cured, the C=C stretching vibration peak at 1720 cm -1 weakens significantly, and the double bond is opened, indicating that the UV-curable polyurea joint sealant can fully react and crosslink under ultraviolet light irradiation.

[0132] Test the mechanical properties of the obtained UV-curable polyurea joint sealant according to the above test method, and the specific test results are shown in Table 2.

[0133] Example 2

[0134] The only difference between this embodiment and Example 1 is that the formulation for preparing the polyurea acrylate prepolymer is as follows:

[0135] Isocyanate (IPDI selected) 4.80g;

[0136] Polyetheramine (D2000 selected) 40.00g;

[0137] Hard monomer (selected MMA) 0.182g;

[0138] Soft monomer (using 2-HEA) 0.182g;

[0139] Functional monomer (HEA selected) 0.156g;

[0140] Catalyst (DBTDL selected) 0.15g;

[0141] Polymerization inhibitor (HQ selected) 0.20g;

[0142] Solvent (acetone preferred) 24.00g.

[0143] The preparation steps and process conditions of the polyurea acrylate prepolymer are the same as those described in Example 1, and the resulting polyurea acrylate prepolymer is abbreviated as P2.

[0144] The number-average molecular weight (Mn), weight-average molecular weight (Mw), glass transition temperature (Tg), double bond content, viscosity, and acid value of the polyurea acrylate prepolymer obtained in this embodiment are shown in Table 1.

[0145] Using the polyurea acrylate prepolymer prepared in this embodiment, and following the formulation and preparation process of the UV-curable polyurea grout described in Example 1, the UV-curable polyurea grout of this embodiment is prepared.

[0146] The test results of various mechanical properties of the UV-cured polyurea grout obtained in this embodiment are detailed in Table 2.

[0147] Example 3

[0148] The only difference between this embodiment and Example 1 is that the formulation for preparing the polyurea acrylate prepolymer is as follows:

[0149] Isocyanate (IPDI selected) 5.00g;

[0150] Polyetheramine (D2000 selected) 40.00g;

[0151] Hard monomer (selected MMA) 0.273g;

[0152] Soft monomer (using 2-HEA) 0.273g;

[0153] Functional monomer (HEA selected) 0.234g;

[0154] Catalyst (DBTDL selected) 0.15g;

[0155] Polymerization inhibitor (HQ selected) 0.20g;

[0156] Solvent (acetone preferred) 24.00g.

[0157] The preparation steps and process conditions of the polyurea acrylate prepolymer are the same as those described in Example 1, and the resulting polyurea acrylate prepolymer is abbreviated as P3.

[0158] The number-average molecular weight (Mn), weight-average molecular weight (Mw), glass transition temperature (Tg), double bond content, viscosity, and acid value of the polyurea acrylate prepolymer obtained in this embodiment are shown in Table 1.

[0159] Using the polyurea acrylate prepolymer prepared in this embodiment, and following the formulation and preparation process of the UV-curable polyurea grout described in Example 1, the UV-curable polyurea grout of this embodiment is prepared.

[0160] The test results of various mechanical properties of the UV-cured polyurea grout obtained in this embodiment are detailed in Table 2.

[0161] Example 4

[0162] The only difference between this embodiment and Example 1 is that the formulation for preparing the polyurea acrylate prepolymer is as follows:

[0163] Isocyanate (IPDI selected) 5.20g;

[0164] Polyetheramine (D2000 selected) 40.00g;

[0165] Hard monomer (selected MMA) 0.364g;

[0166] Soft monomer (using 2-HEA) 0.364g;

[0167] Functional monomer (HEA selected) 0.304g;

[0168] Catalyst (DBTDL selected) 0.15g;

[0169] Polymerization inhibitor (HQ selected) 0.20g;

[0170] Solvent (acetone preferred) 24.00g.

[0171] The preparation steps and process conditions of the polyurea acrylate prepolymer are the same as those described in Example 1, and the resulting polyurea acrylate prepolymer is abbreviated as P4.

[0172] The number-average molecular weight (Mn), weight-average molecular weight (Mw), glass transition temperature (Tg), double bond content, viscosity, and acid value of the polyurea acrylate prepolymer obtained in this embodiment are shown in Table 1.

[0173] Using the polyurea acrylate prepolymer prepared in this embodiment, and following the formulation and preparation process of the UV-curable polyurea grout described in Example 1, the UV-curable polyurea grout of this embodiment is prepared.

[0174] The test results of various mechanical properties of the UV-cured polyurea grout obtained in this embodiment are detailed in Table 2.

[0175] Example 5

[0176] The only difference between this embodiment and Example 1 is that the formulation for preparing the polyurea acrylate prepolymer is as follows:

[0177] Isocyanate (IPDI selected) 5.40g;

[0178] Polyetheramine (D2000 selected) 40.00g;

[0179] Hard monomer (selected MMA) 0.455g;

[0180] Soft monomer (using 2-HEA) 0.455g;

[0181] Functional monomer (HEA selected) 0.39g;

[0182] Catalyst (DBTDL selected) 0.15g;

[0183] Polymerization inhibitor (HQ selected) 0.20g;

[0184] Solvent (acetone preferred) 24.00g.

[0185] The preparation steps and process conditions of the polyurea acrylate prepolymer are the same as those described in Example 1, and the resulting polyurea acrylate prepolymer is abbreviated as P5.

[0186] The number-average molecular weight (Mn), weight-average molecular weight (Mw), glass transition temperature (Tg), double bond content, viscosity, and acid value of the polyurea acrylate prepolymer obtained in this embodiment are shown in Table 1.

[0187] Using the polyurea acrylate prepolymer prepared in this embodiment, and following the formulation and preparation process of the UV-curable polyurea grout described in Example 1, the UV-curable polyurea grout of this embodiment is prepared.

[0188] The test results of various mechanical properties of the UV-cured polyurea grout obtained in this embodiment are detailed in Table 2.

[0189] Example 6

[0190] This embodiment prepares a UV-curable polyurea grout sealant according to the following formula:

[0191] 30.0g of polyurea acrylate prepolymer;

[0192] Reactive diluent (TPGDA:HDDA=1:1) 30.0g;

[0193] Photoinitiator (I2959, solid) 0.5g;

[0194] Photoinitiator (1173, liquid) 0.5g;

[0195] Defoamer (BASF 2410AC) 0.1g;

[0196] Dispersant (BYK-110) 0.2g;

[0197] Filler (fumed silica) 0.5g;

[0198] Filler (quartz powder) 9.5g.

[0199] The polyurea acrylate prepolymer used is the same as the P4 prepared in Example 4;

[0200] The specific preparation method of the UV-cured polyurea grout is the same as that described in Example 1;

[0201] The test results of various mechanical properties of the UV-cured polyurea grout obtained in this embodiment are detailed in Table 2.

[0202] Example 7

[0203] This embodiment prepares a UV-curable polyurea grout sealant according to the following formula:

[0204] 60.0g of polyurea acrylate prepolymer;

[0205] Reactive diluent (TPGDA:HDDA=1:1) 55.0g;

[0206] Photoinitiator (I2959, solid) 2.5g;

[0207] Photoinitiator (1173, liquid) 2.5g;

[0208] Defoamer (BASF 2410AC) 0.5g;

[0209] Dispersant (BYK-110) 1.0g;

[0210] Filler (fumed silica) 1.5g;

[0211] Filler (quartz powder) 28.5g.

[0212] The polyurea acrylate prepolymer used is the same as the P4 prepared in Example 4;

[0213] The specific preparation method of the UV-cured polyurea grout is the same as that described in Example 1;

[0214] The test results of various mechanical properties of the UV-cured polyurea grout obtained in this embodiment are detailed in Table 2.

[0215] Comparative Example 1

[0216] The only difference between this comparative example and Example 1 is that the polyetheramine raw material used to prepare the polyurea acrylate prepolymer is replaced by D230 instead of D2000. All other contents are the same as described in Example 1.

[0217] The number-average molecular weight (Mn), weight-average molecular weight (Mw), glass transition temperature (Tg), double bond content, viscosity, and acid value of the polyurea acrylate prepolymers obtained in this comparative example are shown in Table 1.

[0218] Using the polyurea acrylate prepolymer prepared in this comparative example, the UV-curable polyurea grout of this comparative example was prepared according to the formulation and preparation process of the UV-curable polyurea grout described in Example 1.

[0219] The test results of various mechanical properties of the UV-cured polyurea grout obtained in this comparative example are detailed in Table 2.

[0220] Comparative Example 2

[0221] The only difference between this comparative example and Example 1 is that the amounts of the hard monomers, soft monomers, and functional monomers used to prepare the polyurea acrylate prepolymer are not within the range of the proportions described in this invention. The specific proportions are as follows:

[0222] Isocyanate (IPDI selected) 4.58g;

[0223] Polyetheramine (D2000 selected) 40.00g;

[0224] Hard monomer (selected MMA) 0.0273g;

[0225] Soft monomer (using 2-HEA) 0.0273g;

[0226] Functional monomer (HEA selected) 0.0234g;

[0227] Catalyst (DBTDL selected) 0.15g;

[0228] Polymerization inhibitor (HQ selected) 0.20g;

[0229] Solvent (acetone preferred) 24.00g.

[0230] The rest of the content is the same as described in Example 1.

[0231] The number-average molecular weight (Mn), weight-average molecular weight (Mw), glass transition temperature (Tg), double bond content, viscosity, and acid value of the polyurea acrylate prepolymers obtained in this comparative example are shown in Table 1.

[0232] Using the polyurea acrylate prepolymer prepared in this comparative example, the UV-curable polyurea grout of this comparative example was prepared according to the formulation and preparation process of the UV-curable polyurea grout described in Example 1.

[0233] The test results of various mechanical properties of the UV-cured polyurea grout obtained in this comparative example are detailed in Table 2.

[0234] Comparative Example 3

[0235] The only difference between this comparative example and Example 1 is that the quartz powder filler used in preparing the UV-curable polyurea grout is replaced with an equal amount of titanium dioxide; all other contents are the same as described in Example 1.

[0236] Experiments have shown that, under the same conditions, if titanium dioxide is used as a filler, the resulting polyurea grout will not be able to cure under UV light. This indicates that the excellent performance of the UV-curable polyurea grout described in this invention is not only related to the polyurea acrylate prepolymer, but also requires the synergistic effect of a specific filler (quartz powder).

[0237] Table 1. Performance test results of the polyurea acrylate prepolymers prepared in Examples 1-5 and Comparative Examples 1-2

[0238]

[0239] As shown in Table 1, the number-average molecular weight (Mn) of the polyurea acrylate prepolymers prepared in Examples 1-5 were all between 6000 and 8000, the weight-average molecular weight (Mw) was all between 7500 and 9500, the glass transition temperature (Tg) was all between -40℃ and -20℃, and the double bond (C=C) content was all between 1.0 and 1.5 mmol / g. In contrast, the number-average molecular weight (only 907) and weight-average molecular weight (only 1506) of the polyurea acrylate prepolymer prepared in Comparative Example 1 were significantly lower than the molecular weights described in this invention, and the molecular weight distribution index (1.66) was greater than 1.3, while the glass transition temperature (-12℃) was higher than the Tg range described in this invention. The double bond content (0.3 mmol / g) of the polyurea acrylate prepolymer prepared in Comparative Example 2 was significantly higher than the double bond content range described in this invention.

[0240] Table 2 Performance test results of UV-cured polyurea grout prepared in Examples 1-7 and Comparative Examples 1-2

[0241]

[0242] As shown in Table 2, the UV-curable polyurea grout prepared in Examples 1-7 not only achieve rapid curing (curing time of only 0.5 min), but also exhibit excellent mechanical properties. Specifically, the tensile strength is greater than 8 MPa, the elongation at break is within the range of 30% to 60%, the pencil hardness is consistently at 4H, the flexibility reaches 1 mm, and the impact resistance reaches 40-50 kg·cm, achieving a good balance between rigidity and flexibility with strong impact resistance. In addition, they have excellent adhesion, with all examples showing an adhesion grade of 1, demonstrating excellent bonding performance. The gloss can be flexibly adjusted within the range of 55.7 to 79.8, meeting a wide range of needs from matte to high gloss. Furthermore, they exhibit outstanding hydrophobic and moisture-proof properties, specifically: the contact angle is greater than 80°, indicating good surface hydrophobicity; the water absorption rate is less than 2%, demonstrating excellent moisture-proof performance.

[0243] Comparative Example 1, due to the significantly lower number-average molecular weight (only 907) and weight-average molecular weight (only 1506) of its prepared polyurea acrylate prepolymer compared to the molecular weight described in this invention, and its molecular weight distribution index (1.66) > 1.3, and glass transition temperature (-12℃) higher than the Tg range described in this invention, resulted in a UV-cured polyurea grout with an elongation at break of only 15.35% and an impact resistance of only 10 kg·cm under the same conditions. Comparative Example 2, on the other hand, had a significantly higher double bond content (0.3 mmol / g) than the double bond content range described in this invention, resulting in a UV-cured polyurea grout with a curing time that was twice as long (reaching 1 min) and a tensile strength of only 5.87 MPa, while its elongation at break was as high as 60.12%, all other things being equal. The pencil hardness is only H grade; obviously, if the performance of the polyurea acrylate prepolymer does not meet the special conditions described in this invention, a UV-cured polyurea grout product with excellent comprehensive performance cannot be obtained; only by using the polyurea acrylate prepolymer with the performance specified in this invention can the prepared UV-cured polyurea grout achieve a balance of properties such as rapid curing, high strength, high hardness, good flexibility, strong adhesion, and hydrophobicity and moisture resistance.

[0244] Figure 2 These are photographs showing the water resistance test results of the UV-cured polyurea grout prepared in Examples 1-7. Figure 2 As shown, the UV-cured polyurea grout prepared in Examples 1 to 7 did not show any peeling after being soaked in water for 24 hours, demonstrating excellent water resistance. In particular, the water resistance of Examples 2 to 5 was the best.

[0245] The experimental results above demonstrate that this invention, by employing a specific polyurea acrylate prepolymer, not only enables the prepared UV-curable polyurea grout to achieve rapid UV curing and convenient construction, but also achieves excellent mechanical properties such as high strength, high hardness, high toughness, high adhesion, and impact resistance. Furthermore, it possesses stable and durable hydrophobic and waterproof capabilities, making it suitable for tile grouting in damp environments such as kitchens and bathrooms. In addition, the gloss level can be flexibly adjusted within the range of 55.7 to 79.8, meeting a wide range of needs from matte to high gloss. Moreover, the preparation method of the UV-curable polyurea grout described in this invention is simple, easy to scale up, and exhibits good process stability. Therefore, this invention successfully resolves the contradiction between curing speed, mechanical balance, durability, and decorative effect that is difficult to balance in traditional grout products, demonstrating significant progress and application value compared to existing grout products.

[0246] Finally, it should be noted that the above are only some preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A UV-curable polyurea grout sealant, characterized in that, It is made using the following formula: 30-60 parts by weight of polyurea acrylate prepolymer; 30-60 parts by weight of reactive diluent; 1-5 parts by weight of photoinitiator; Defoamer 0.1-0.5 parts by weight; Dispersant 0.2–1 parts by weight; 10-30 parts by weight of filler; The polyurea acrylate prepolymer has a number-average molecular weight (Mn) of 6000–8000, a weight-average molecular weight (Mw) of 7500–9500, a glass transition temperature (Tg) of -40℃ to -20℃, and a double bond (C=C) content of 1.0–1.5 mmol / g.

2. The UV-curable polyurea grout sealant according to claim 1, characterized in that, The polyurea acrylate prepolymer is made from the following raw materials: 4-6 parts by weight of isocyanate; 30-50 parts by weight of polyetheramine; Hard monomer 0.05-0.5 parts by weight; Soft monomer 0.05-0.5 parts by weight; Functional monomers, 0.05–0.5 parts by weight; Catalyst: 0.1–0.3 parts by weight; Polymerization inhibitor: 0.1–0.3 parts by weight; Solvent 20-30 parts by weight.

3. The UV-curable polyurea grout sealant according to claim 2, characterized in that: The isocyanate is selected from any one of isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), diphenylmethane diisocyanate (MDI), and toluene diisocyanate (TDI); the polyetheramine is selected from any one of D230, D400, and D2000.

4. The UV-curable polyurea grout sealant according to claim 2, characterized in that: The hard monomer is selected from methyl methacrylate (MMA) and / or methyl acrylate (MA); the soft monomer is selected from any one or more of ethyl acrylate (EA), n-butyl acrylate (n-BA), lauryl acrylate (LA), 2-ethylhexyl acrylate (2-HEA), and lauryl methacrylate (LMA); the functional monomer is selected from any one or more of hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), acrylamide, and hydroxypropyl methacrylate (HPMA).

5. The UV-curable polyurea grout sealant according to claim 2, characterized in that: The catalyst is selected from any one of dibutyltin dilaurate (DBTDL) and dibutyltin dioctanoate (DBTO); the polymerization inhibitor is selected from any one of hydroquinone (HQ), p-hydroxyanisole (MEHQ), 2,6-di-tert-butyl-p-cresol (BHT), and methyl hydroquinone (THQ).

6. The UV-curable polyurea grout sealant according to claim 2, characterized in that: The solvent is selected from any one of acetone, ethyl acetate, toluene, dibutyl phthalate (DBP), and dioctyl phthalate (DOP).

7. The UV-curable polyurea grout sealant according to claim 2, characterized in that, The preparation of the polyurea acrylate prepolymer includes the following steps: S1) Under nitrogen protection, first add the required amount of isocyanate and solvent to the reaction vessel, then heat it to 50-60°C in a water bath, and add the required amount of polyetheramine dropwise while stirring, controlling the dropwise rate so that the internal temperature does not exceed 60°C. After S2) is finished, maintain the internal temperature at 50-60℃ to continue the reaction; when the content of the remaining isocyanate group (-NCO) is monitored to be 5wt%-10wt%, raise the internal temperature to 55-65℃, and add a mixture of functional monomer and about 1 / 3 catalyst in the specified amount while stirring. After S3) drops are completed, maintain the internal temperature at 55-65℃ to continue the reaction; when the content of the remaining isocyanate group (-NCO) is monitored to be 0.5wt%-2wt%, add a mixture of the specified amount of soft monomer and about 1 / 3 of the specified amount of catalyst dropwise under stirring. After S4) the reaction is completed, maintain the internal temperature at 55-65℃ and continue the reaction; when the residual -NCO content is monitored to be 0.05wt%-0.2wt%, add a mixture of the specified amount of hard monomer and the remaining amount of catalyst dropwise while stirring. After S5) the reaction is completed, the internal temperature is maintained at 55-65℃ to continue the reaction; when the content of residual isocyanate group (-NCO) is ≤0.01wt%, the trace amount of by-product low-boiling substances is removed by vacuum to obtain acrylate-terminated polyurea macromonomer. S6) Reduce the temperature of the reaction system to 50-60℃, add the specified amount of polymerization inhibitor, and keep the system warm and stir until the system is uniform and transparent. S7) Turn off the nitrogen gas, stop stirring, allow it to cool naturally to room temperature, and filter to obtain a colorless to slightly yellow liquid polyurea acrylate prepolymer.

8. The UV-curable polyurea grout sealant according to claim 2, characterized in that: The polyetheramine, hard monomers, soft monomers, and functional monomers are all pre-treated under vacuum at 60–80°C to achieve a moisture content of ≤0.05%.

9. The UV-curable polyurea grout sealant according to claim 1, characterized in that: The reactive diluent is selected from any one or two of tripropylene glycol diacrylate (TPGDA), trimethylolpropane triacrylate (TMPTA), 1,6-hexanediol diacrylate (HDDA), and isobornyl acrylate (IBOA); the photoinitiator is selected from diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (I2959), and 2-hydroxy-2-methyl-1-propanone. The defoamer is selected from any one or two of phenyl-1-propanone (1173) and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (819); the defoamer is selected from any one of BASF 2410AC, BYK-A530, and BYK-014; the dispersant is selected from any one of BYK-110, BYK-2152, and BYK-AT204; the filler is selected from any one or more of fumed silica, calcium carbonate, barium sulfate, quartz, alumina, and hydrotalcite.

10. A method for preparing the UV-curable polyurea grout sealant according to claim 1, characterized in that, Includes the following steps: a) Under yellow light, add the solid photoinitiator in the formula to 1 / 12 to 1 / 6 of the amount of reactive diluent, and heat in a water bath at 80 to 100°C until it is completely dissolved to obtain solution A, which is then set aside. b) Add the specified amount of polyurea acrylate prepolymer, the remaining specified amount of reactive diluent, the liquid photoinitiator, defoamer, and dispersant from the formulation to the mixing tank, and stir at 800–1000 rpm until they are uniformly mixed; then add the specified amount of filler, and stir at 1000–2000 rpm until they are uniformly mixed. c) Add solution A to the mixture obtained in step b) and stir at 800-1000 rpm until it is uniformly mixed to obtain the UV-curable polyurea grout, which is a uniformly dispersed and opaque liquid product.

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