A high-strength, yellowing-resistant, and moisture-proof two-component polyurethane grout sealant, its preparation method, and its application.

Abstract

This invention relates to a high-strength, yellowing-resistant, and moisture-proof two-component polyurethane grout sealant, its preparation method, and its application, belonging to the field of grout sealant technology. The sealant comprises component A and component B. Component A contains a polyether polyol, a silicone-containing polyether polyol, a first inorganic powder, a molecular sieve activated powder, and a first catalyst. Component B contains an HDI trimer and a second inorganic powder. The silicone-containing polyether polyol is prepared by a ring-opening reaction between a small-molecule silicone-containing polyol and a resin with epoxy groups under the action of a second catalyst. This invention, by introducing a silicone-containing polyether polyol prepared through a ring-opening reaction, utilizes its hydrophobic properties to effectively solve the problem of foaming in conventional polyurethane grout sealants in humid environments. It also improves the adhesion strength to the tile glaze and exhibits excellent yellowing resistance and good mechanical properties. This product is suitable for tile grouting or decorative grouting in humid environments such as kitchens, bathrooms, and balconies.

Description

Technical Field

[0001] This invention relates to the field of tile grout technology, and in particular to a high-strength, yellowing-resistant, and moisture-proof two-component polyurethane tile grout, its preparation method, and its application. Background Technology

[0002] Grout is a crucial material for filling gaps after tile installation, and its performance directly affects the decorative effect and lifespan. Currently, the grouts available on the market are mainly two-component epoxy resin grout and two-component polyurea grout. Two-component epoxy grout has advantages such as low shrinkage, good stain resistance, and a dense, smooth surface, but its resistance to yellowing is poor, especially in areas exposed to ultraviolet radiation such as balconies and windows, where noticeable yellowing can occur within a short period. Furthermore, while epoxy grout has high hardness after curing, it lacks toughness, and its high shrinkage rate after long-term use can easily lead to problems such as delamination and cracking. Two-component polyurea grout cures quickly and has good weather resistance, but it generally suffers from a short working period, especially in hot and humid summer environments where the grout rapidly forms a skin and hardens, leaving the grout installer insufficient time to smooth and polish it. Additionally, polyurea grout has poor adhesion to the tile glaze, easily causing delamination in stress-concentrated areas such as corners.

[0003] Two-component polyurethane grout theoretically combines the advantages of both epoxy and polyurea by selecting raw materials such as aliphatic isocyanates and yellowing-resistant polyols to achieve resistance to yellowing and adjustable application time. However, when conventional two-component polyurethane grout is applied in humid environments, the isocyanate component reacts with moisture to produce carbon dioxide gas, causing the grout to foam and blister, severely affecting the grout's finish and waterproofing performance. This problem of moisture-curing foaming has long remained unresolved, which is the main reason why there are currently almost no mature two-component polyurethane grout products on the market.

[0004] Taking an existing polyurethane grout, a commercially available epoxy grout, and a commercially available polyurea grout as examples, their typical performance is compared as follows: The existing polyurethane grout has a tensile strength of approximately 9 MPa, an elongation at break of approximately 23%, and an adhesive strength of approximately 6.8 MPa (tile failure); the commercially available epoxy grout has a tensile strength of approximately 19 MPa but an elongation at break of only approximately 3.8%, and an adhesive strength of approximately 4 MPa (debonding); the commercially available polyurea grout has a tensile strength of approximately 3.5 MPa and an adhesive strength of approximately 3.5-4.5 MPa (debonding). It is evident that both the commercially available epoxy and polyurea grouts exhibit debonding, while the existing polyurethane grout, although not debonding, has significantly insufficient mechanical properties. In summary, existing grouts cannot simultaneously meet the comprehensive requirements of high tensile strength, high elongation at break, and high adhesive strength.

[0005] Therefore, developing a two-component polyurethane grout that can simultaneously meet the requirements of high strength, yellowing resistance, adjustable working time, and bubble-free curing in humid environments has significant market value and technical significance. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a two-component polyurethane grout that simultaneously meets the requirements of high strength, yellowing resistance, adjustable working time, and non-foaming curing in humid environments, as well as its preparation method and application.

[0007] Through extensive experimentation, the inventors unexpectedly discovered that a ring-opening reaction between small-molecule silicon-containing polyols (such as dimethylsilanediol and methylsilanetriol) and epoxy resins (such as epoxidized soybean oil and epoxidized fatty acid methyl esters) under the action of an alkaline catalyst yields products with excellent compatibility with ordinary polyether polyols, and significantly superior hydrophobicity and adhesion compared to simple physical mixing. Based on this discovery, the inventors completed this invention.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a high-strength, yellowing-resistant, and moisture-proof two-component polyurethane grout sealant, comprising component A and component B. Component A comprises a polyether polyol, a silicone-containing polyether polyol, a first inorganic powder, a molecular sieve activated powder, and a first catalyst. Component B comprises an HDI trimer and a second inorganic powder. The silicone-containing polyether polyol is prepared by a ring-opening reaction between a small-molecule silicone-containing polyol and a resin with epoxy groups under the action of a second catalyst.

[0009] As a preferred embodiment of the two-component polyurethane grout sealant of the present invention, the small molecule silicon-containing polyol is selected from at least one of dimethylsilanediol, methylsilanetriol, 1,1-bis(1-methylethyl)silanediol, and diethylsilanediol.

[0010] In a preferred embodiment of the two-component polyurethane grout sealant of the present invention, the resin with epoxy groups is selected from at least one of propylene oxide, epoxidized fatty acid methyl ester, and epoxidized soybean oil.

[0011] As a preferred embodiment of the two-component polyurethane grout sealant of the present invention, the hydroxyl value of the silicone polyether polyol is 300~330 mg KOH / g, and the epoxy value is less than 1%.

[0012] As a preferred embodiment of the two-component polyurethane grout sealant of the present invention, the first catalyst is selected from at least one of stannous octoate, dibutyltin dilaurate, bismuth isooctanoate, and zinc isooctanoate, or a compound of bismuth isooctanoate and zinc isooctanoate; and / or, the second catalyst is potassium hydroxide.

[0013] Preferably, the first catalyst is a compound of bismuth isooctanoate and zinc isooctanoate in a mass ratio of 1:1.

[0014] In a preferred embodiment of the two-component polyurethane grout sealant of the present invention, the first inorganic powder and the second inorganic powder are each independently selected from at least one of silica powder and calcium carbonate; and / or, the molecular sieve activated powder is selected from at least one of 3A, 4A, 5A, and 13X type molecular sieves.

[0015] In a preferred embodiment of the two-component polyurethane grout sealant of the present invention, each of the A and B components independently further includes at least one of hydrophobic fumed silica, a dispersant, a leveling agent, and a defoamer.

[0016] In a preferred embodiment of the two-component polyurethane grout sealant of the present invention, the molecular weight of the polyether polyol is 400~5000 g / mol.

[0017] Secondly, the present invention provides a method for preparing the above-mentioned high-strength, yellowing-resistant, and moisture-proof two-component polyurethane sealant, comprising the following steps: mixing the raw materials of component A evenly according to the ratio, vacuum degassing, and dispensing; mixing the raw materials of component B evenly according to the ratio, vacuum degassing, and dispensing; and mixing component A and component B through a mixing tube and extruding to obtain the sealant.

[0018] Thirdly, the present invention provides the application of the above-mentioned two-component polyurethane grout in tile grouting or grouting decoration in humid environments such as kitchens, bathrooms, and balconies.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention discloses a high-strength, yellowing-resistant, and moisture-proof two-component polyurethane grout sealant. Component A comprises polyether polyol, silicone polyether polyol, a first inorganic powder, molecular sieve activated powder, and a first catalyst; component B comprises HDI trimer and a second inorganic powder; wherein the silicone polyether polyol is prepared by a ring-opening reaction between a small molecule silicone polyol and a resin with epoxy groups.

[0020] This invention introduces a silicone-containing polyether polyol into component A, which has strong hydrophobicity and can effectively suppress the side reaction between moisture and isocyanate. After curing at 85% relative humidity and 25℃, no visible bubbles were found in the cross-sections of Examples 1-3, while bubbles appeared in Comparative Examples 1 and 4, indicating that this invention is less prone to bubble formation under high temperature and humidity conditions. This invention uses an aliphatic HDI trimer and a yellowing-resistant polyether polyol system. The yellowing resistance ΔE values ​​of Examples 1-3 are all less than the standard requirement (<1), while Comparative Example 3 is higher than 1, indicating that this invention has comparable or superior UV yellowing resistance. Simultaneously, the bond strength of Examples 1-3 under different conditions is higher than ≥3. The tensile strength of Examples 1-3 is 13-14 MPa (standard requirement) and higher than that of Comparative Examples 1-4 (comparative Examples 1-3 all showed delamination), indicating that the present invention has a stronger bond with the ceramic tile glaze. The silicone polyether polyol used in Examples 1-3 and ordinary polyether polyol were mixed at a 1:1 ratio and left to stand for 24 hours without separation, while Comparative Example 4 showed separation. Comparative Example 3 is an epoxy system and is immiscible with polyether, proving that the ring-opening reaction effectively improves the compatibility between the silicone component and the polyether polyol. The tensile strength of Examples 1-3 is 13-14 MPa and the elongation at break is 36-40%, both of which meet the standard requirements and have better comprehensive mechanical properties than Comparative Examples 1, 2, and 4. The elongation at break is better than that of Comparative Example 3, and there is a significant improvement compared to the existing polyurethane grout (9 MPa, 23%) described in the background art.

[0021] In summary, this invention prepares silicone polyether polyols by ring-opening reaction of small-molecule silicone polyols with epoxy groups, achieving bubble-free curing of two-component polyurethane grout in humid environments. It also takes into account yellowing resistance, high adhesion, good compatibility and excellent mechanical properties, and has broad application prospects. Detailed Implementation

[0022] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. The embodiments described below are some, but not all, embodiments of this invention. The embodiments of this invention are used to illustrate the invention, not to limit it. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. Unless otherwise specified, experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the manufacturer. The raw materials and reagents used are commercially available conventional products or products that conform to relevant national / industry standards and are all commercially available.

[0023] Source of raw materials Except for the silicone polyether polyol, which was prepared in-house, the raw materials used in the examples, including polyether polyol, silicon micro powder, calcium carbonate, molecular sieve activated powder, HDI trimer, stannous octoate, potassium hydroxide, epoxidized soybean oil, epoxidized fatty acid methyl ester, dimethylsilanediol, and methylsilanetriol, are all commercially available industrial products. Those skilled in the art can choose equivalent substitutes as needed, without being limited to specific brands or models.

[0024] The preparation methods for silicone polyether polyols SP-1 and SP-2 are detailed in the "Preparation of Silicone Polyether Polyols" section below.

[0025] Preparation of silicone-containing polyether polyols Preparation of silicone-containing polyether polyol SP-1 Dimethylsilanediol (DMSD) and potassium hydroxide were mixed and stirred thoroughly at a mass ratio of 100:0.5. After purging with nitrogen twice, the mixture was heated to 110-120℃. Epoxidized soybean oil (ESO) was then slowly added dropwise, with the temperature controlled at 110-130℃ during the addition process. The addition was completed in 3-4 hours, maintaining a pressure <0.25MPa. The reaction was continued at 110-120℃ for 2-4 hours until the pressure dropped below 0.1MPa. A sample was taken and the epoxy value was measured to be <1%, and the hydroxyl value was 300-330 mg KOH / g. The sample was then neutralized to a pH of approximately 6, washed 2-3 times with water, and dehydrated under vacuum to obtain a silicone-containing polyether polyol, designated SP-1.

[0026] Preparation of silicone-containing polyether polyol SP-2 The preparation of SP-2 differs from that of SP-1 in that: dimethylsilanediol in SP-1 is replaced with an equal amount of methylsilanetriol (MST), and epoxidized soybean oil (ESO) is replaced with an equal amount of epoxidized fatty acid methyl ester (EFAME). The remaining components and preparation process are the same as those of SP-1, resulting in a silicone-containing polyether polyol, denoted as SP-2.

[0027] Example 1 (Preferred Formula) 1. Preparation of silicone-containing polyether polyol SP-1 100g of dimethylsilanediol (DMSD) was mixed with 0.5g of potassium hydroxide and stirred until homogeneous. After purging with nitrogen twice, the mixture was heated to 115℃. 120g of epoxidized soybean oil (ESO) was then slowly added dropwise, with the temperature controlled at 120℃±5℃ during the addition process. The addition was completed in 3.5 hours, maintaining a pressure of 0.20-0.22MPa. The reaction was continued at 115℃ for 3 hours until the pressure dropped to 0.08MPa. A sample was taken and the epoxy value was measured to be 0.6%, and the hydroxyl value was 315mg KOH / g. The mixture was then neutralized to approximately pH 6, washed three times with water, and dehydrated under vacuum to obtain the silicone-containing polyether polyol SP-1.

[0028] 2. Formulation of two-component polyurethane grout This embodiment provides a high-strength, yellowing-resistant, and moisture-proof two-component polyurethane grout sealant, the formula of which is as follows by weight: Component A: 40 parts of polyether polyol (PPG-2000), 60 parts of silicone polyether polyol (SP-1), 30 parts of silica powder, 20 parts of calcium carbonate, 5 parts of 4A molecular sieve activated powder, 0.1 parts of bismuth isooctanoate and zinc isooctanoate compounded in a 1:1 mass ratio, hydrophobic fumed silica, 0.3 parts of dispersant, 0.2 parts of leveling agent, and 0.1 parts of defoamer.

[0029] Component B: 80 parts HDI trimer, 15 parts silica powder, 5 parts calcium carbonate, 0.3 parts hydrophobic fumed silica, 0.2 parts dispersant, 0.1 parts leveling agent, and 0.1 parts defoamer.

[0030] 3. Preparation method of two-component polyurethane grout sealant This embodiment provides a method for preparing the above-mentioned two-component polyurethane grout sealant, the steps of which are as follows: (1) Bake the silica powder, calcium carbonate and hydrophobic fumed silica in component A at 150°C for 10-12 hours, and then cool them to room temperature in a sealed container for later use; the silica powder, calcium carbonate and hydrophobic fumed silica in component B are treated in the same way. (2) Add each raw material of component A into a planetary mixer according to the ratio, stir for 30 minutes under vacuum of -0.095MPa, and dispense the material into 400mL two-component tubes; (3) Add each raw material of component B to the planetary mixer according to the ratio, stir for 30 minutes under vacuum of -0.095MPa, and dispense the material into 400mL two-component tubes; (4) When using, install the static mixing tube with the two-component tube containing components A and B, and use an electric glue gun to squeeze out the first 30cm and discard it. After squeezing out, the two-component polyurethane sealant of this embodiment is obtained.

[0031] The properties of the tile grout prepared by the above method after curing are shown in Table 2.

[0032] The inventors believe that the main reason for the performance improvement is that silicon atoms in the silicon-containing polyether polyol form chemical bonds with the polyether segments through a ring-opening reaction. This retains the flexibility of the polyether segments while introducing the strong hydrophobicity and high adhesion activity to inorganic surfaces of the silicon-containing segments. Simultaneously, the chemical bond structure formed by the ring-opening reaction effectively solves the compatibility problem between the silicon-containing component and ordinary polyether polyols, ensuring the stability of the formulation system.

[0033] Example 2 The difference between this embodiment and Example 1 is that the amount of polyether polyol in component A is 70 parts, and the amount of silicone polyether polyol (SP-1) is 30 parts. The remaining components and preparation methods are the same as in Example 1.

[0034] Example 3 Preparation of silicone-containing polyether polyol SP-2 100g of methylsilanetriol (MST) was mixed with 0.5g of potassium hydroxide and stirred until homogeneous. After purging with nitrogen twice, the mixture was heated to 115℃. 130g of epoxy fatty acid methyl ester (EFAME) was then slowly added dropwise, with the temperature controlled at 120℃±5℃. The addition was completed in 3.5 hours, maintaining a pressure of 0.20-0.22MPa. The reaction was continued at 115℃ for 3 hours until the pressure dropped to 0.08MPa. A sample was taken and the epoxy value was measured to be 0.7%, and the hydroxyl value was 308mg KOH / g. The mixture was then neutralized to approximately pH 6, washed three times with water, and dehydrated under vacuum to obtain the silicone-containing polyether polyol SP-2.

[0035] The difference between this embodiment and Example 1 is that the amount of polyether polyol in component A is 20 parts, and the amount of silicone polyether polyol (SP-2) is 80 parts. The remaining components and preparation methods are the same as in Example 1.

[0036] Comparative Example 1 The difference between this comparative example and Example 1 is that no silicone-containing polyether polyol is added to component A, and the polyether polyol is adjusted to 40 parts PPG-2000 and 60 parts MN-500, for a total of 100 parts. The remaining components and preparation methods are the same as in Example 1.

[0037] Comparative Example 2 Commercially available two-component polyurea grout sealant (brand and model omitted) was selected as comparative example 2 and tested under the same conditions. The results are shown in Table 1.

[0038] Comparative Example 3 Commercially available two-component epoxy grout sealant (brand and model omitted) was selected as comparative example 3 and tested under the same conditions. The results are shown in Table 1.

[0039] Comparative Example 4 The difference between this comparative example and Example 1 is that: instead of adding silicone polyether polyol SP-1 to component A, an equal weight of physically mixed silicone polyols is added.

[0040] The preparation method of the physically mixed silicon-containing polyol is as follows: dimethylsilanediol and polyether polyol (PPG-2000) are directly and physically mixed uniformly at a mass ratio of 60:40, without ring-opening reaction bonding. The remaining components and preparation methods are the same as in Example 1.

[0041] Performance testing 1. Sample preparation and numbering The two-component polyurethane grout prepared in Examples 1-3 and Comparative Examples 1-4 above, as well as commercially available products (Comparative Examples 2 and 3), were monitored for use.

[0042] 2. Testing Methods The test methods for each performance test item are shown in the table below. The specific operation shall be carried out in accordance with the relevant standard.

[0043] Table 1

[0044] Note: Moisture curing and foaming observation: After mixing components A and B, the mixture is poured into a mold and cured for 24 hours under conditions of relative humidity 85±5% and temperature 25±2℃. The cured sample is then removed, and the cross-sectional bubble situation is observed. No visible bubbles are recorded as "no bubbles", a small number of dispersed bubbles are recorded as "small bubbles", and dense or large bubbles are recorded as "large bubbles".

[0045] Compatibility observation: Mix the test sample (containing silicone polyether polyol, or the substitute in the comparative example) with polyether polyol (PPG-2000) at a mass ratio of 1:1, let it stand at room temperature for 24 hours, and observe whether the mixture separates into layers. If the mixture remains homogeneous and transparent without separation, it is recorded as "no separation"; if obvious separation of the two phases occurs, it is recorded as "separation".

[0046] 3. Test Results The samples were numbered as follows: Sample A (Example 1), Sample B (Example 2), Sample C (Example 3), Sample D (Comparative Example 1), Sample E (Comparative Example 2), Sample F (Comparative Example 3), and Sample G (Comparative Example 4). Samples A and B were subjected to the aforementioned performance tests, and the results are shown in Table 2 below.

[0047] Table 2

[0048] Note: Sample D (Comparative Example 1) does not contain silicon-containing components and is not suitable for compatibility testing; Sample E (Comparative Example 2) and Sample F (Comparative Example 3) are not polyurethane systems and are immiscible with polyether, and are also not suitable for compatibility testing.

[0049] 4. Test Result Analysis As shown in Table 2, the abrasion resistance, flexural strength, compressive strength, shrinkage value, water absorption, tensile strength, elongation at break, yellowing resistance, and bonding strength under various conditions of Examples 1-3 all meet the standard requirements, and there are no bubbles or delamination. Comparative Examples 1-4, however, exhibit varying degrees of non-compliance with standard requirements, bubbles, or delamination. Compared to the existing polyurethane grout described in the background art (tensile strength approximately 9 MPa, elongation at break approximately 23%), the tensile strength (13-14 MPa) and elongation at break (36-40%) of Examples 1-3 are significantly improved.

[0050] The inventors believe that the reason why this solution can achieve the above-mentioned performance improvement is that the ring-opening reaction product of small molecule silicon-containing polyol and epoxy resin has a unique chemical structure. It retains the strong hydrophobicity and high adhesive activity of silicon-containing segments, and improves the compatibility with polyether polyol through chemical bonding. This allows the grout to cure without bubbles in a humid environment, while obtaining excellent adhesive strength, yellowing resistance and mechanical properties.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high-strength, yellowing-resistant, and moisture-proof two-component polyurethane grout sealant, comprising component A and component B, characterized in that, Component A comprises polyether polyol, silicone-containing polyether polyol, first inorganic powder, molecular sieve activated powder, and first catalyst; Component B comprises HDI trimer and a second inorganic powder. The silicon-containing polyether polyol is prepared by a ring-opening reaction between a small molecule silicon-containing polyol and a resin with epoxy groups under the action of a second catalyst.

2. The two-component polyurethane caulk according to claim 1, characterized in that The small molecule silicon-containing polyol is selected from at least one of dimethylsilanediol, methylsilanetriol, 1,1-bis(1-methylethyl)silanediol, and diethylsilanediol.

3. The two-component polyurethane caulk according to claim 1, wherein The resin with epoxy groups is selected from at least one of propylene oxide, epoxidized fatty acid methyl ester, and epoxidized soybean oil.

4. The two-component polyurethane caulk according to claim 1, wherein The hydroxyl value of the silicone polyether polyol is 300~330 mg KOH / g, and the epoxy value is less than 1%.

5. The two-component polyurethane caulk according to claim 1, wherein The first catalyst is selected from at least one of stannous octoate, dibutyltin dilaurate, bismuth isooctanoate, and zinc isooctanoate, or a complex of bismuth isooctanoate and zinc isooctanoate; and / or, the second catalyst is potassium hydroxide.

6. The two-component polyurethane caulk according to claim 1, wherein The first inorganic powder and the second inorganic powder are each independently selected from at least one of silica powder and calcium carbonate.

7. The two-component polyurethane caulk according to claim 1, wherein The molecular sieve activation powder is selected from at least one of 3A, 4A, 5A, and 13X molecular sieves; and / or, the molecular weight of the polyether polyol is 400~5000 g / mol.

8. The two-component polyurethane caulk according to claim 1, wherein Component A and Component B each independently include at least one of hydrophobic fumed silica, dispersant, leveling agent, and defoamer.

9. A process for the preparation of a high strength, yellowing resistant, moisture resistant two-component polyurethane sealant according to any one of claims 1 to 8, characterized in that, Includes the following steps: Mix all raw materials of component A according to the specified ratio, degas under vacuum, and package. Mix all raw materials of component B according to the specified ratio, degas under vacuum, and package. When using, mix components A and B through a mixing tube and extrude to obtain the final product.

10. The application of a two-component polyurethane grout sealant according to any one of claims 1 to 8 in tile grouting or decorative grouting in damp environments such as kitchens, bathrooms, and balconies.

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