A method for preparing a two-component polyurethane anti-abrasion marking paint

Abstract

The application relates to the paint technology field and discloses a preparation method of a two-component polyurethane anti-abrasion marking paint, wherein the marking paint comprises A component: 100 parts by weight of water-based polyester polyol, 35-42 parts by weight of pigment, 1-1.4 parts by weight of dispersant and the like. B component is 21-28 parts by weight of isocyanate curing agent. The side chain of the water-based polyester polyol contains hydrophilic sulfonate groups, so that the polyester polyol and the paint A component have good hydrophilicity and water dispersibility. After being cured with the isocyanate curing agent, siloxane structural units are introduced into the polyurethane molecular chain, the toughness and the anti-abrasion performance of the paint film are improved, and the paint film has higher impact resistance, flexibility and water resistance. The prepared paint has good practical application in outdoor traffic sign marking and the like.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a method for preparing a two-component polyurethane anti-wear marking coating. Background Technology

[0002] Waterborne polyurethane coatings are environmentally friendly, have good film-forming properties, and excellent corrosion resistance, making them widely used in flooring decoration, wooden furniture, and automobile manufacturing. Two-component polyurethane coatings typically consist of polyol components and isocyanate curing agents. Traditional waterborne polyurethane coatings suffer from poor abrasion resistance and waterproofing, limiting their practical application in outdoor transportation, road marking, and other applications.

[0003] Common polyols used in polyurethanes include polyether polyols and polyester polyols, which have a significant impact on the performance of polyurethanes and their coatings. Chinese patent CN118580480B discloses an organosilicon-modified polyester polyol, its preparation method, and its application. The method involves reacting carboxyl or hydroxyl-terminated MDT silicone resin with a diacid and a diol to obtain an organosilicon-modified polyester polyol, which can improve the adhesion, tensile strength, and other properties of polyurethanes. However, the polyurethane in this patent does not have water-based properties and good abrasion resistance, which is not conducive to the practical application of polyurethanes in abrasion-resistant water-based coatings and other applications. Summary of the Invention

[0004] (i) The technical problem solved by the present invention is that the two-component polyurethane coating has poor wear resistance and waterproof performance.

[0005] (II) The technical solution of the present invention is: a two-component polyurethane anti-wear marking coating and its preparation method. The coating includes component A and component B. Component A consists of 100 parts by weight of waterborne polyester polyol, 0.3-0.8 parts by weight of defoamer, 0.3-0.6 parts by weight of leveling agent, 35-42 parts by weight of pigment, and 1-1.4 parts by weight of dispersant. Component B is 21-28 parts by weight of isocyanate curing agent.

[0006] The preparation method of the coating is as follows: water, water-based polyester polyol, defoamer, leveling agent, pigment and dispersant are added to a container, and sheared and dispersed to obtain component A; component B isocyanate curing agent is added to obtain a two-component polyurethane anti-wear marking coating.

[0007] The preparation method of waterborne polyester polyol is as follows: add polyol, acid anhydride monomer, polyacid, and sodium organosilicon sulfonate dicarboxylic acid to the reaction vessel, purge with nitrogen to remove air, heat to the esterification reaction temperature, stir to carry out the esterification reaction, and remove the generated water; evacuate, heat to the polycondensation reaction temperature, add the catalyst dibutyltin dilaurate, stir to carry out the polycondensation reaction until the acid value drops to about 1 mg KOH / g, cool down and discharge to obtain waterborne polyester polyol.

[0008] Preferably, the molar ratio of polyol, acid anhydride monomer, polyacid, and sodium organosilicon sulfonate dicarboxylic acid is (140-160):(25-32):(50-58):(10-25).

[0009] Preferably, the polyol is any one or a combination of ethylene glycol, neopentyl glycol, and diethylene glycol.

[0010] Preferably, the polyacid is succinic acid or adipic acid.

[0011] Preferably, the anhydride monomer is phthalic anhydride or tetrahydrophthalic anhydride.

[0012] Preferably, the esterification reaction temperature is 180-190℃ and the esterification reaction time is 3-4h; the polycondensation reaction temperature is 225-240℃.

[0013] The preferred method for preparing sodium organosilicon sulfonate dicarboxylic acid is as follows:

[0014] (1) Add ethanol, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and 4-formylbenzoic acid to the reaction vessel, stir at room temperature for 2-3 h, then add sodium borohydride and continue the reaction for 3-4 h, add hydrochloric acid solution to adjust the pH to 4-5, precipitate out, filter, dry to obtain organosilicon dicarboxylic acid.

[0015] .

[0016] (2) Add acetonitrile, organosilicon dicarboxylic acid in a molar ratio of 1:(2-2.6):(2.8-3.2), sodium 2-bromoethanesulfonate, and sodium carbonate to the reaction vessel. Heat to 40-55℃ and react for 8-12 hours. Remove acetonitrile by rotary evaporation, dilute with sodium chloride solution, extract with dichloromethane, and rotary evaporate the organic phase. Recrystallize the product in an 80% (v / v) aqueous ethanol solution to obtain organosilicon dicarboxylic acid sodium sulfonate. The reaction formula is:

[0017] .

[0018] Preferably, in (1), 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and 4-formylbenzoic acid are stirred at room temperature for 2-3 hours, and then sodium borohydride is added in a molar ratio of 1:(2-2.1):(2.2-2.4).

[0019] (III) Beneficial Technical Effects: This invention uses dibutyltin dilaurate as a catalyst and sodium organosilicon sulfonate as a functional monomer to undergo esterification and polycondensation reactions with polyols such as neopentyl glycol, polyacids such as adipic acid, and anhydride monomers such as phthalic anhydride to obtain a water-based polyester polyol. This water-based polyol is then compounded with pigments, dispersants, etc., to form component A of a polyurethane coating. The side chains of the polyester polyol contain hydrophilic sulfonate groups, giving both the polyester polyol and component A of the coating good hydrophilicity and water dispersibility.

[0020] This invention uses isocyanate curing agent as component B. After curing with component A, siloxane structural units are introduced into the polyurethane molecular chain, improving the toughness and wear resistance of the coating film. It exhibits higher impact resistance and flexibility. Simultaneously, the siloxane structure has strong water resistance and is not easily hydrolyzed, further enhancing the water resistance of the polyurethane. The resulting coating has excellent practical applications in outdoor traffic signs and markings. Detailed Implementation

[0021] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention.

[0022] Example 1:

[0023] (1) Add 700 mL of ethanol, 20 mmol of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and 40 mmol of 4-formylbenzoic acid to the reaction vessel, stir at room temperature for 3 h, then add 48 mmol of sodium borohydride and continue the reaction for 3 h, add hydrochloric acid solution to adjust the pH to 4, precipitate out, filter, dry, and obtain organosilicon dicarboxylic acid.

[0024] (2) Add 250 mL of acetonitrile, 20 mmol of organosilicon dicarboxylic acid, 40 mmol of sodium 2-bromoethanesulfonate, and 56 mmol of sodium carbonate to the reaction vessel, heat to 55 °C, react for 8 h, remove acetonitrile by rotary evaporation, dilute with 20% sodium chloride solution, extract with dichloromethane, evaporate the organic phase by rotary evaporation, and recrystallize the product in 80% ethanol aqueous solution to obtain sodium organosilicon sulfonate dicarboxylic acid.

[0025] (3) Add 102 mmol neopentyl glycol, 45 mmol diethylene glycol, 58 mmol adipic acid, 10 mmol sodium organosilicon sulfonate dicarboxylic acid, and 32 mmol phthalic anhydride to the reactor, purge with nitrogen to remove air, heat to 180°C, stir and react for 4 hours, and remove the generated water; evacuate, heat to 230°C, add 0.064 g of catalyst dibutyltin dilaurate, stir and react until the acid value drops to about 1 mg KOH / g, cool and discharge to obtain water-based polyester polyol.

[0026] (4) Add 140mL of water, 100g of waterborne polyester polyol, 0.3g of defoamer (FoamStar ED2522), 0.5g of leveling agent (TEGO4100), 38g of pigment titanium dioxide, and 1.2g of dispersant (TEGO-715W) to the container, and shear and disperse to obtain component A; add 23g of isocyanate curing agent (Covestro xp2655) to component B to obtain a two-component polyurethane anti-wear marking paint.

[0027] Example 2:

[0028] (1) Add 800 mL of ethanol, 20 mmol of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and 42 mmol of 4-formylbenzoic acid to the reaction vessel, stir at room temperature for 2 h, then add 44 mmol of sodium borohydride and continue the reaction for 4 h, add hydrochloric acid solution to adjust the pH to 5, precipitate out, filter, dry, and obtain organosilicon dicarboxylic acid.

[0029] (2) Add 250 mL of acetonitrile, 20 mmol of organosilicon dicarboxylic acid, 52 mmol of sodium 2-bromoethanesulfonate, and 64 mmol of sodium carbonate to the reaction vessel, heat to 40 °C, react for 12 h, remove acetonitrile by rotary evaporation, dilute with 20% sodium chloride solution, extract with dichloromethane, evaporate the organic phase by rotary evaporation, and recrystallize the product in 80% ethanol aqueous solution to obtain sodium organosilicon sulfonate dicarboxylic acid.

[0030] (3) Add 93 mmol neopentyl glycol, 67 mmol ethylene glycol, 59 mmol succinic acid, 15 mmol sodium organosilicon sulfonate dicarboxylic acid and 26 mmol tetrahydrophthalic anhydride to the reactor, purge with nitrogen to remove air, heat to 190°C, stir and react for 3 h, and remove the generated water; evacuate, heat to 225°C, add 0.072 g of catalyst dibutyltin dilaurate, stir and react until the acid value drops to about 1 mg KOH / g, cool and discharge to obtain water-based polyester polyol.

[0031] (4) Add 160mL of water, 100g of waterborne polyester polyol, 0.8g of defoamer (FoamStar ED2522), 0.3g of leveling agent (TEGO4100), 42g of pigment titanium dioxide, and 1.4g of dispersant (TEGO-715W) to the container, and shear and disperse to obtain component A; add 21g of isocyanate curing agent (Covestro xp2655) to component B to obtain a two-component polyurethane anti-wear marking paint.

[0032] Example 3:

[0033] (1) Add 82 mmol neopentyl glycol, 58 mmol ethylene glycol, 53 mmol adipic acid, 20 mmol sodium organosilicon sulfonate dicarboxylic acid (prepared from Example 1), and 27 mmol phthalic anhydride to the reactor, purge with nitrogen to remove air, heat to 185°C, stir and react for 4 h, and remove the generated water; evacuate, heat to 240°C, add 0.055 g of catalyst dibutyltin dilaurate, stir and react until the acid value drops to about 1 mg KOH / g, cool and discharge to obtain water-based polyester polyol.

[0034] (2) Add 160mL of water, 100g of waterborne polyester polyol, 0.4g of defoamer (FoamStar ED2522), 0.6g of leveling agent (TEGO4100), 35g of pigment titanium dioxide, and 1g of dispersant (TEGO-715W) to the container, and shear and disperse to obtain component A; add 28g of isocyanate curing agent (Covestro xp2655) to component B to obtain a two-component polyurethane anti-wear marking paint.

[0035] Example 4:

[0036] (1) Add 88 mmol neopentyl glycol, 61 mmol ethylene glycol, 50 mmol adipic acid, 25 mmol sodium organosilicon sulfonate dicarboxylic acid (prepared from Example 1), and 25 mmol phthalic anhydride to the reactor, purge with nitrogen to remove air, heat to 180°C, stir and react for 4 h, and remove the generated water; evacuate, heat to 240°C, add 0.058 g of catalyst dibutyltin dilaurate, stir and react until the acid value drops to about 1 mg KOH / g, cool and discharge to obtain water-based polyester polyol.

[0037] (2) Add 150mL of water, 100g of waterborne polyester polyol, 0.8g of defoamer (FoamStar ED2522), 0.3g of leveling agent (TEGO4100), 35g of pigment titanium dioxide, and 1g of dispersant (TEGO-715W) to the container, and shear and disperse to obtain component A; add 26g of isocyanate curing agent (Covestro xp2655) to component B to obtain a two-component polyurethane anti-wear marking paint.

[0038] Comparative Example 1:

[0039] (1) Add 102 mmol neopentyl glycol, 45 mmol diethylene glycol, 58 mmol adipic acid, 10 mmol terephthalic acid and 32 mmol phthalic anhydride to the reactor, purge with nitrogen to remove air, heat to 180°C, stir and react for 4 h, and remove the generated water; evacuate, heat to 230°C, add 0.064 g of catalyst dibutyltin dilaurate, stir and react until the acid value drops to about 1 mg KOH / g, cool down and discharge to obtain polyester polyol.

[0040] (2) Add 140mL of water, 100g of polyester polyol, 0.3g of defoamer (FoamStar ED2522), 0.5g of leveling agent (TEGO4100), 38g of pigment titanium dioxide, and 1.2g of dispersant (TEGO-715W) to the container, and shear and disperse to obtain component A; add 23g of isocyanate curing agent (Covestro xp2655) to component B to obtain a two-component polyurethane anti-wear marking paint.

[0041] Comparative Example 2:

[0042] (1) 700 mL of ethanol, 20 mmol of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, and 40 mmol of 4-formylbenzoic acid were added to a reaction vessel. The mixture was stirred at room temperature for 3 h, and then distilled under reduced pressure. The product was recrystallized in dichloromethane to obtain an organosilicon dicarboxylic acid. The structural formula is as follows: .

[0043] (2) Add 102 mmol neopentyl glycol, 45 mmol diethylene glycol, 58 mmol adipic acid, 10 mmol organosilicon dicarboxylic acid and 32 mmol phthalic anhydride to the reactor, purge with nitrogen to remove air, heat to 180°C, stir and react for 4 h, and remove the generated water; evacuate, heat to 230°C, add 0.064 g of catalyst dibutyltin dilaurate, stir and react until the acid value drops to about 1 mg KOH / g, cool down and discharge to obtain polyester polyol.

[0044] (3) Add 140mL of water, 100g of polyester polyol, 0.3g of defoamer (FoamStar ED2522), 0.5g of leveling agent (TEGO4100), 38g of pigment titanium dioxide, and 1.2g of dispersant (TEGO-715W) to the container, and shear and disperse to obtain component A; add 23g of isocyanate curing agent (Covestro xp2655) to component B to obtain a two-component polyurethane anti-wear marking paint.

[0045] Comparative Example 3:

[0046] (1) Add 102 mmol neopentyl glycol, 45 mmol diethylene glycol, 58 mmol adipic acid, 10 mmol sodium isophthalic acid-5-sulfonate (CAS No. 6362-79-4), and 32 mmol phthalic anhydride to the reactor, purge with nitrogen to remove air, heat to 180°C, stir and react for 4 h, and remove the generated water; evacuate, heat to 230°C, add 0.064 g of catalyst dibutyltin dilaurate, stir and react until the acid value drops to about 1 mg KOH / g, cool and discharge to obtain water-based polyester polyol.

[0047] (2) Add 140mL of water, 100g of waterborne polyester polyol, 0.3g of defoamer (FoamStar ED2522), 0.5g of leveling agent (TEGO4100), 38g of pigment titanium dioxide, and 1.2g of dispersant (TEGO-715W) to the container, and shear and disperse to obtain component A; add 23g of isocyanate curing agent (Covestro xp2655) to component B to obtain a two-component polyurethane anti-wear marking paint.

[0048] The dispersibility of the emulsion was observed after placing component A of the coating at room temperature for 60 days.

[0049] The coating is applied to the surface of the tinplate substrate and dried and cured at 70℃ for 24 hours. Abrasion resistance and friction loss are tested according to GB / T 1768-2006. Impact resistance of the coating film is tested according to GB / T 1732-2020. Flexibility is tested according to GB / T 1731-2020. Water resistance is tested according to GB / T 1733-1993.

[0050] Table 1

[0051]

[0052] The table above shows that the A component of the coatings in Examples 1-4 did not separate after storage and exhibited excellent emulsion dispersibility. This is because the side chains of the polyester polyol contain hydrophilic sulfonate groups, giving the polyester polyol good hydrophilicity and water dispersibility. Furthermore, after curing with the isocyanate curing agent, the resulting polyurethane film exhibits low frictional mass loss, excellent abrasion resistance, impact resistance, and flexibility, as well as superior water resistance. This is mainly because the molecular backbone of the water-based polyester polyol contains siloxane structural units, which can improve the toughness and abrasion resistance of the polyurethane film, resulting in higher impact resistance and flexibility. Simultaneously, the siloxane structure has strong water resistance and is not easily hydrolyzed, thereby improving the water resistance of the polyurethane.

[0053] Comparative Example 1 uses terephthalic acid instead of sodium organosilicon sulfonate dicarboxylic acid. The side chain of the prepared polyester polyol does not contain hydrophilic sulfonate groups, resulting in poor dispersibility of the water emulsion of component A of the coating and easy separation. At the same time, the main chain of the polyester polyol and the prepared polyurethane does not contain siloxane structure, resulting in poor abrasion resistance, flexibility, impact resistance and water resistance of the paint film.

[0054] Comparative Example 2 uses organosilicon dicarboxylic acid as a raw material to prepare polyester polyol. The side chain does not contain hydrophilic sulfonate groups, resulting in poor dispersibility of water emulsion of component A of the coating and easy separation. However, the polyurethane coating film has excellent wear resistance, flexibility, impact resistance and water resistance.

[0055] Comparative Example 3 uses conventional sodium isophthalate-5-sulfonate as raw material to prepare a polyester polyol with hydrophilic sulfonate groups in its side chain. The water emulsion of component A of the coating has good dispersibility and does not separate. However, the main chain of the polyester polyol and the prepared polyurethane does not contain siloxane structure, resulting in poor abrasion resistance, flexibility, impact resistance and water resistance of the paint film.

[0056] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing a two-component polyurethane anti-wear marking paint, characterized in that, The preparation method includes the following steps: S1. Add polyol, acid anhydride monomer, polyacid, and structural formula [missing information] to the reaction vessel. Sodium organosilicon sulfonate dicarboxylic acid is purged with nitrogen to purge air, heated to the esterification reaction temperature, stirred to carry out the esterification reaction, and the generated water is removed; vacuum is applied, heated to the polycondensation reaction temperature, a catalyst is added, stirred to carry out the polycondensation reaction, cooled and discharged to obtain water-based polyester polyol. S2. Add water, 100 parts by weight of waterborne polyester polyol, 0.3-0.8 parts by weight of defoamer, 0.3-0.6 parts by weight of leveling agent, 35-42 parts by weight of pigment, and 1-1.4 parts by weight of dispersant to a container, and shear and disperse to obtain component A; add 21-28 parts by weight of isocyanate curing agent (component B) to obtain a two-component polyurethane anti-wear marking paint. The preparation method of the sodium organosilicon sulfonate dicarboxylic acid is as follows: (1) Add ethanol, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and 4-formylbenzoic acid to the reaction vessel, stir the reaction at room temperature for 2-3 h, then add sodium borohydride, continue the reaction for 3-4 h, add hydrochloric acid solution to adjust the pH to 4-5, precipitate out the precipitate, filter, dry, and obtain organosilicon dicarboxylic acid; (2) Add acetonitrile, organosilicon dicarboxylic acid, sodium 2-bromoethanesulfonate, and sodium carbonate to the reaction vessel, heat to 40-55℃, react for 8-12 hours, remove acetonitrile by rotary evaporation, dilute with sodium chloride solution, extract, and recrystallize the product in an ethanol aqueous solution to obtain sodium organosilicon dicarboxylic acid. In step (1), 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and 4-formylbenzoic acid are stirred at room temperature for 2-3 hours, and then sodium borohydride is added in a molar ratio of 1:(2-2.1):(2.2-2.4). The molar ratio of organosilicon dicarboxylic acid, sodium 2-bromoethanesulfonate, and sodium carbonate in (2) is 1:(2-2.6):(2.8-3.2).

2. The preparation method of the two-component polyurethane anti-wear marking paint according to claim 1, characterized in that, The molar ratio of the polyol, acid anhydride monomer, polyacid, and sodium organosilicon sulfonate dicarboxylic acid is (140-160):(25-32):(50-58):(10-25).

3. The preparation method of the two-component polyurethane anti-wear marking paint according to claim 2, characterized in that, The polyol is any one or a combination of ethylene glycol, neopentyl glycol, and diethylene glycol.

4. The preparation method of the two-component polyurethane anti-wear marking paint according to claim 2, characterized in that, The polyacid is succinic acid or adipic acid, and the anhydride monomer is phthalic anhydride or tetrahydrophthalic anhydride.

5. The preparation method of the two-component polyurethane anti-wear marking paint according to claim 1, characterized in that, The catalyst in S1 is dibutyltin dilaurate.

6. The preparation method of the two-component polyurethane anti-wear marking paint according to claim 1, characterized in that, The esterification reaction temperature in S1 is 180-190℃, and the esterification reaction time is 3-4h; the polycondensation reaction temperature is 225-240℃.

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