A modified waterborne polyurethane dispersion, its preparation method and use

Abstract

The application relates to the technical field of water-based polyurethane dispersions, and specifically discloses a modified water-based polyurethane dispersion as well as a preparation method and application thereof. The modified water-based polyurethane dispersion comprises the following raw materials in parts by weight: 10-20 parts of a composite material, 1.2-3.5 parts of a polyol, 0.02-0.05 parts of a catalyst, 0.01-0.05 parts of a polymerization inhibitor, 1-5 parts of a neutralizing agent, 1-3 parts of a chain extender and 50-70 parts of water, wherein the composite material is used for modifying a polyurethane prepolymer to obtain the modified water-based polyurethane dispersion; and the preparation method comprises the following steps: uniformly mixing the composite material, the polyol, the catalyst and the polymerization inhibitor, heating, and keeping warm to obtain a mixture, adding the chain extender, the neutralizing agent and the water into the mixture, heating, and keeping warm to obtain the modified water-based polyurethane dispersion. The modified water-based polyurethane dispersion has the advantages of improving stain resistance through the synergistic effect of the raw materials.

Description

A modified waterborne polyurethane dispersion, its preparation method and application Technical Field

[0001] This application relates to the field of waterborne polyurethane dispersion technology, and in particular to a modified waterborne polyurethane dispersion, its preparation method and application. Background Technology

[0002] With the development of materials technology, high performance and low VOC have become the direction of coating development. Waterborne polyurethane dispersions, due to their use of water as the main dispersion medium, are not easily flammable and are environmentally friendly. Their unique soft and hard segment copolymer structure gives them excellent low-temperature resistance, hand feel, and hardness, which has attracted much attention and led to their widespread use in textiles, leather, adhesives, inks and other fields.

[0003] In the field of commercially available electronic devices, such as mobile phones, tablets, laptops, and automotive interiors, various substrates such as plastics, metals, and peels are used. It is generally desirable to cover these substrates with easy-to-clean coatings that have excellent adhesion, as well as stain-resistant and scratch-resistant coatings for various plastic substrates.

[0004] Because waterborne polyurethane structures are copolymerized from hard isocyanates and soft polyols, and hydrophilic groups are introduced, the soft polyester polyols are easily hydrolyzed and the polyether polyols are easily hygroscopic. Although existing waterborne polyurethane dispersions have good adhesion and pencil hardness, they have poor stain resistance. Summary of the Invention

[0005] To improve the stain resistance of waterborne polyurethane dispersions, this application provides a modified waterborne polyurethane dispersion, its preparation method, and its application.

[0006] In a first aspect, this application provides a modified waterborne polyurethane dispersion, employing the following technical solution:

[0007] A modified waterborne polyurethane dispersion comprises the following raw materials in parts by weight: 10-20 parts of composite material, 1.2-3.5 parts of polyol, 0.02-0.05 parts of catalyst, 0.01-0.05 parts of polymerization inhibitor, 1-5 parts of neutralizer, 1-3 parts of chain extender, and 50-70 parts of water, wherein the composite material is prepared by modifying polyurethane prepolymer with adipamide hydrazine.

[0008] By adopting the above technical solution, the modified waterborne polyurethane dispersion of this application can not only maintain good hardness, gloss and adhesion through the synergistic effect between the raw materials, but also improve the stain resistance. The pencil hardness is FH, the gloss at 60° angle is 92-98, the adhesion is 0-2, and the stain resistance is 3-5.

[0009] The composite material is prepared by modifying polyurethane prepolymer with adipic hydrazide, wherein adipic hydrazide is an acylhydrazide monomer. The polyurethane prepolymer is crosslinked by adipic hydrazide, and acylhydrazide groups are introduced into the molecular chain of the polyurethane prepolymer. As water evaporates, the ketone carbonyl group and the acylhydrazide group undergo a dehydration condensation reaction to generate crosslinking bonds, which gives it a lower surface tension and can improve the stability of the composite material. While maintaining the good pencil hardness and adhesion of the modified waterborne polyurethane dispersion, the lower surface tension can significantly improve the stain resistance of the composite material, thereby improving the stain resistance of the modified waterborne polyurethane dispersion.

[0010] Polyols are the basic components, and catalysts can promote the reaction, save time, and improve efficiency; polymerization inhibitors, neutralizers, and chain extenders are also basic components, which facilitates the preparation of modified waterborne polyurethane dispersions.

[0011] Preferably, the composite material is prepared by the following method: a polyurethane prepolymer is placed in water and dispersed, diacetone acrylate and potassium persulfate are added and mixed evenly to obtain a mixture; adipamide is added to the mixture, mixed evenly, and dried to obtain the composite material.

[0012] Furthermore, the composite material is prepared by the following method: the polyurethane prepolymer is placed in water and dispersed at a speed of 2500-3000 r / min for 10-30 min; diacetone acrylate and potassium persulfate are added and mixed evenly to obtain a mixture; adipamide hydrazine is added to the mixture, mixed evenly, and dried to obtain the composite material.

[0013] The amount of water added per 1g of polyurethane prepolymer is 5-7mL, the weight ratio of polyurethane prepolymer to diacetone acrylate is 1:(0.3-0.5), and the weight ratio of polyurethane prepolymer to potassium persulfate is 1:(0.002-0.005).

[0014] By adopting the above technical solution, a mixture is first prepared to facilitate more uniform mixing of the raw materials. Then, adipamide is added to the composite to obtain a composite material, which facilitates better crosslinking and modification of adipamide with the composite, thereby improving the stain resistance of the composite material and thus improving the stain resistance of the modified waterborne polyurethane dispersion.

[0015] Preferably, the weight ratio of the polyurethane prepolymer to adipamide is 1:(0.6-0.8).

[0016] Insufficient addition of adipic acid hydrazine results in insufficient crosslinking modification of the polyurethane prepolymer with the hydrazine, failing to optimally improve the stain resistance of the modified waterborne polyurethane dispersion. Excessive addition of adipic acid hydrazine not only increases production costs but also leads to waste. By adopting the above technical solution, when the weight ratio of polyurethane prepolymer to adipic acid hydrazine is within the specified range, not only can costs be saved, but the stain resistance of the composite material can also be improved, thereby enhancing the stain resistance of the modified waterborne polyurethane dispersion.

[0017] Preferably, the polyurethane prepolymer is prepared by the following method: hydroxyethyl acrylate, toluene diisocyanate, and dimethylolpropionic acid are mixed evenly, triethylenediamine is added, heated and kept at a constant temperature, tridecafluorooctyl alcohol is added, heated and reacted, acetone is added, mixed evenly, triethylamine is added for chain extension, and rotary evaporation is performed to obtain the polyurethane prepolymer.

[0018] Furthermore, the polyurethane prepolymer is prepared by the following method: hydroxyethyl acrylate, toluene diisocyanate, and dimethylolpropionic acid are mixed evenly, triethylenediamine is added, and the mixture is heated to 50-60°C and kept at that temperature for 1.5-2.5 hours. Tridecafluorooctyl alcohol is added, and the mixture is heated to 70-90°C and reacted for 1-3 hours. Acetone is added, and the mixture is mixed evenly. Triethylamine is then added for chain extension, and the mixture is rotary evaporated to obtain the polyurethane prepolymer.

[0019] Specifically, the amount of hydroxyethyl acrylate added per 1g of toluene diisocyanate is 0.5-1mL, the amount of dimethylolpropionic acid added per 1g of toluene diisocyanate is 0.5-1.5g, the amount of triethylenediamine added per 1g of toluene diisocyanate is 0.5-1g, the amount of acetone added per 1g of toluene diisocyanate is 1-2mL, and the amount of triethylamine added per 1g of toluene diisocyanate is 0.1-0.5mL.

[0020] By adopting the above technical solution and using the above preparation method to prepare polyurethane prepolymer, tridecanoic acid is added to the raw materials of polyurethane prepolymer to introduce fluorine-containing groups. Triethylenediamine can introduce vinyl groups, which can enhance the compatibility of tridecanoic acid and toluene diisocyanate. This can give the polyurethane prepolymer extremely low surface energy, enhance hydrophobicity and oleophobicity, reduce surface tension, and further improve stain resistance, thereby improving the stain resistance of the modified waterborne polyurethane dispersion.

[0021] Preferably, the weight ratio of toluene diisocyanate and tridecafluorooctyl alcohol is 1:(0.4-0.6).

[0022] Insufficient addition of tridecafluorooctyl alcohol results in fewer introduced fluorinated groups, failing to optimally improve the stain resistance of the modified waterborne polyurethane dispersion. Conversely, excessive addition leads to saturation of the fluorinated groups introduced onto toluene diisocyanate, not only failing to further improve stain resistance but also wasting the tridecafluorooctyl alcohol. By employing the aforementioned technical solution, when the addition amounts of toluene diisocyanate and tridecafluorooctyl alcohol are within the specified range, the stain resistance of the modified waterborne polyurethane dispersion can be optimally improved.

[0023] Preferably, the polyol is one or more of polyether diol, polycarbonate diol, and polyester diol, and the catalyst is one or more of dimethylcyclohexylamine, dibutyltin dilaurate, and N-ethylmorpholine.

[0024] Preferably, the neutralizing agent is one or more of ammonia and N,N-dimethylethanolamine, and the chain extender is one or more of ethylenediamine, hexamethylenediamine, and m-phenylenediamine.

[0025] By adopting the above technical solution, the polyol, catalyst, neutralizer, and chain extender are limited, which facilitates the improvement of the stain resistance of the modified waterborne polyurethane dispersion.

[0026] Secondly, this application provides a method for preparing a modified waterborne polyurethane dispersion, which adopts the following technical solution: A method for preparing a modified waterborne polyurethane dispersion includes the following steps:

[0027] The composite material, polyol, catalyst, and polymerization inhibitor are mixed evenly, heated, and kept at a certain temperature to obtain a mixture. A chain extender, neutralizer, and water are added to the mixture, and the mixture is heated and kept at a certain temperature to obtain a modified waterborne polyurethane dispersion.

[0028] Furthermore, a method for preparing a modified waterborne polyurethane dispersion includes the following steps:

[0029] The composite material, polyol, catalyst, and polymerization inhibitor are mixed evenly and heated to 60-80℃ for 2-4 hours to obtain a mixture. A chain extender, neutralizer, and water are added to the mixture, and the mixture is heated to 80-90℃ for 3-6 hours to obtain a modified waterborne polyurethane dispersion.

[0030] By adopting the above technical solution and using the above method to prepare the modified waterborne polyurethane dispersion, it is easier to mix the raw materials more evenly and improve the stain resistance of the modified waterborne polyurethane dispersion.

[0031] Thirdly, this application provides an application of a modified waterborne polyurethane dispersion, employing the following technical solution:

[0032] The application of a modified waterborne polyurethane dispersion in coatings, wherein the addition amount of the modified waterborne polyurethane dispersion is 85-90 wt%.

[0033] By adopting the above technical solution, the modified waterborne polyurethane dispersion can be used in coatings to improve the stain resistance of the resulting paint film.

[0034] In summary, this application includes at least one of the following beneficial technical effects:

[0035] 1. Because this application uses adipamide hydrazide to crosslink the polyurethane prepolymer, hydrazide groups are introduced into the polyurethane prepolymer molecular chain to generate crosslinking bonds, which makes it have a lower surface tension and can significantly improve the stain resistance of the composite material, thereby improving the stain resistance of the modified waterborne polyurethane dispersion. It can make the pencil hardness reach H, the gloss at 60° angle reach 98, the adhesion reach 0 level, and the stain resistance reach 5 points.

[0036] 2. In this application, a polyurethane prepolymer is preferably prepared mainly from tridecylfluorooctyl alcohol and toluene diisocyanate. The introduction of fluorine-containing groups can give the polyurethane prepolymer extremely low surface energy, enhance its hydrophobicity and oleophobicity, reduce surface tension, and further improve the stain resistance of the polyurethane prepolymer, thereby improving the stain resistance of the modified waterborne polyurethane dispersion. Detailed Implementation

[0037] The following provides a more detailed description of this application in conjunction with specific details.

[0038] raw material

[0039] The polyol is polyhexanediol, with a molecular weight of 860 and a viscosity of 350-850 mPa·s; the catalyst is dimethylcyclohexylamine; the neutralizing agent is N,N-dimethylethanolamine; and the chain extender is ethylenediamine.

[0040] Preparation Example

[0041] Preparation Example 1

[0042] A polyurethane prepolymer is prepared by the following method:

[0043] 1.4 L of hydroxyethyl acrylate, 2 kg of toluene diisocyanate, and 2 kg of dimethylolpropionic acid were mixed evenly. 1.4 kg of triethylenediamine was added, and the mixture was heated to 55 °C and kept at that temperature for 2 h. 0.8 kg of tridecafluorooctyl alcohol was added, and the mixture was heated to 80 °C and reacted for 2 h. 3 L of acetone was added, and the mixture was mixed evenly. Then, 0.5 L of triethylamine was added for chain extension, and the mixture was rotary evaporated to obtain a polyurethane prepolymer.

[0044] Preparation Example 2

[0045] A polyurethane prepolymer differs from Preparation Example 1 in that the amount of tridecafluorooctyl alcohol added is different; in Preparation Example 2, the amount of tridecafluorooctyl alcohol added is 1 L.

[0046] Preparation Example 3

[0047] A polyurethane prepolymer differs from that in Preparation Example 1 in that the amount of tridecafluorooctyl alcohol added is different; in Preparation Example 3, the amount of tridecafluorooctyl alcohol added is 1.2 L.

[0048] Preparation Example 4

[0049] A composite material prepared by the following method:

[0050] 2 kg of the polyurethane prepolymer prepared in Preparation Example 1 was placed in 12 L of water and dispersed at 2700 r / min for 20 min. 0.8 kg of diacetone acrylate and 0.006 kg of potassium persulfate were added and mixed evenly to obtain a mixture. 1.2 kg of adipic hydrazide was added to the mixture and mixed evenly. The mixture was then dried to obtain the composite material.

[0051] Preparation Example 5

[0052] A composite material, which differs from Preparation Example 4 in that the source of the polyurethane prepolymer is different; the polyurethane prepolymer in Preparation Example 5 was prepared using Preparation Example 2.

[0053] Preparation Example 6

[0054] A composite material, which differs from Preparation Example 4 in that the source of the polyurethane prepolymer is different; the polyurethane prepolymer in Preparation Example 6 was prepared using Preparation Example 3.

[0055] Preparation Example 7

[0056] A composite material differs from Preparation Example 5 in that the amount of adipic hydrazide added is different; in Preparation Example 7, the amount of adipic hydrazide added is 1.4 kg.

[0057] Preparation Example 8

[0058] A composite material differs from Preparation Example 5 in that the amount of adipic hydrazide added is different; in Preparation Example 8, the amount of adipic hydrazide added is 1.6 kg.

[0059] Example

[0060] Example 1

[0061] A modified waterborne polyurethane dispersion, the raw material ratio of which is shown in Table 1.

[0062] A method for preparing a modified waterborne polyurethane dispersion includes the following steps:

[0063] The composite material prepared in Preparation Example 4, polyol, catalyst, and polymerization inhibitor were mixed evenly and heated to 70°C for reaction. The mixture was kept at this temperature for 3 hours to obtain a mixture. Chain extender, neutralizer, and water were added to the mixture, and the mixture was heated to 85°C for 4.5 hours to obtain a modified waterborne polyurethane dispersion.

[0064] Example 2-3

[0065] A modified waterborne polyurethane dispersion differs from Example 1 in that the raw material ratio of the polyurethane dispersion is different, as shown in Table 1.

[0066] Table 1. Raw materials of polyurethane dispersions in different embodiments.

[0067]

[0068]

[0069] Examples 4-5

[0070] A modified waterborne polyurethane dispersion differs from Example 2 in that the raw material ratio of the polyurethane dispersion is different, as shown in Table 2.

[0071] Table 2. Raw materials of polyurethane dispersions in different embodiments.

[0072] Raw materials Example 4 Example 5 Composite material 15 15 Polyol 2.8 3.5 Catalyst 0.03 0.05 Polymerization inhibitor 0.03 0.05 Neutralizer 35 Chain extender 23 Water 60 70 surface

[0073] Example 6

[0074] A modified waterborne polyurethane dispersion differs from Example 4 in that the source of the composite material in the polyurethane dispersion is different; it is prepared using Preparation Example 5.

[0075] Example 7

[0076] A modified waterborne polyurethane dispersion differs from Example 4 in that the source of the composite material in the polyurethane dispersion is different; it was prepared using Preparation Example 6.

[0077] Example 8

[0078] A modified waterborne polyurethane dispersion differs from Example 4 in that the source of the composite material in the polyurethane dispersion is different; it was prepared using Preparation Example 7.

[0079] Example 9

[0080] A modified waterborne polyurethane dispersion differs from Example 4 in that the source of the composite material in the polyurethane dispersion is different; it was prepared using Preparation Example 8.

[0081] Comparative Example

[0082] Comparative Example 1

[0083] A modified waterborne polyurethane dispersion differs from Example 1 in that the polyurethane dispersion uses an equal amount of the polyurethane prepolymer prepared in Example 1 to replace the composite material.

[0084] Application examples

[0085] Application Example 1

[0086] A coating comprises the following steps: mixing 87 wt% of a modified waterborne polyurethane dispersion prepared in Example 1, 0.6 wt% of BYK346 leveling agent, 5 wt% of EEH, 0.5 wt% of isoamyl alcohol, 0.2 wt% of hydroxymethyl cellulose, and 6.7 wt% of water evenly to obtain the coating.

[0087] Application Example 2-9

[0088] A coating, which differs from Application Example 1 in that the modified waterborne polyurethane dispersion was prepared using Examples 2-9.

[0089] Application Comparative Example 1

[0090] A coating, which differs from Application Example 1 in that the modified waterborne polyurethane dispersion was prepared using Comparative Example 1.

[0091] Performance testing

[0092] The modified waterborne polyurethane dispersions in corresponding use cases 1-9 and application comparison example 1 were subjected to the following performance tests:

[0093] Pencil hardness: The hardness of the coating was determined according to GB / T6739-1996 "Determination of Hardness of Coating Film by Pencil Test". The test results are shown in Table 3.

[0094] Adhesion: The adhesion of the coating was determined according to GB / T9286-1998 "Cross-cut test of paint and varnish film". The test results are shown in Table 3.

[0095] 60° Angle Gloss: The 60° angle gloss of the coating was determined according to GB / T9754-2007 "Determination of 20°, 60° and 85° Specular Gloss of Paint Films without Metallic Pigments". The test results are shown in Table 3.

[0096] Stain resistance: Draw on the paint film with an oil-based marker, wipe it with a non-woven cloth, and observe the residue of the drawing on the paint film. Score according to the residue after wiping. 5 points means no residue, 0 points means no change in residue, and 5-0 points means an increase in residue.

[0097] Table 3 Detection Results

[0098]

[0099]

[0100] As can be seen from Table 3, the modified waterborne polyurethane dispersion of this application, through the synergistic effect between the raw materials, can not only maintain good hardness, gloss and adhesion, but also improve stain resistance. Specifically, the pencil hardness is FH, the gloss at a 60° angle is 92-98, the adhesion is 0-2, and the stain resistance is 3-5.

[0101] Combining Application Example 1 and Application Comparative Example 1, it can be seen that the paint film in Application Example 1 has a pencil hardness of F, a gloss of 92 at a 60° angle, an adhesion grade of 2, and a stain resistance score of 3, which is better than that of the Application Comparative Example. This indicates that it is more suitable to modify the polyurethane prepolymer with adipamide hydrazine in the composite material. It can not only maintain the good hardness, gloss and adhesion of the paint film, but also improve the stain resistance of the modified polyurethane dispersion.

[0102] As can be seen from Application Examples 1-3, the paint film in Application Example 2 has a pencil hardness of F, a gloss of 93 at a 60° angle, an adhesion grade of 2, and a stain resistance score of 4, which is better than other application examples. This indicates that the amount of composite material added in Application Example 2 is more appropriate, which can not only maintain the good hardness, gloss and adhesion of the paint film, but also improve the stain resistance of the modified polyurethane dispersion.

[0103] As can be seen from Application Examples 4 and 5, the raw materials other than the composite material in the modified waterborne polyurethane dispersion have little impact on its performance.

[0104] As can be seen from Application Examples 6-9, the paint film in Application Example 8 has a pencil hardness of H, a gloss of 98 at a 60° angle, an adhesion grade of 0, and a stain resistance score of 5, which is better than other application examples. This indicates that the polyurethane prepolymer prepared by Preparation Example 2 is more suitable, and the composite material prepared by Preparation Example 7 is more suitable. It can not only maintain the good hardness, gloss, and adhesion of the paint film, but also improve the stain resistance of the modified polyurethane dispersion.

[0105] The embodiments described above are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A modified waterborne polyurethane dispersion, characterized in that: It comprises the following raw materials in parts by weight: 10-20 parts of composite material, 1.2-3.5 parts of polyol, 0.02-0.05 parts of catalyst, 0.01-0.05 parts of polymerization inhibitor, 1-5 parts of neutralizer, 1-3 parts of chain extender, and 50-70 parts of water. The composite material is prepared by modifying a polyurethane prepolymer with adipamide. The polyurethane prepolymer is prepared by: mixing hydroxyethyl acrylate, toluene diisocyanate, and dimethylolpropionic acid uniformly, adding triethylenediamine, heating and maintaining the temperature, adding tridefluorooctyl alcohol, heating and reacting, adding acetone, mixing uniformly, adding triethylamine for chain extension, and rotary evaporation to obtain the polyurethane prepolymer. The composite material is prepared by: dispersing the polyurethane prepolymer in water, adding diacetone acrylamide and potassium persulfate, mixing uniformly to obtain a mixture; adding adipamide to the mixture, mixing uniformly, and drying to obtain the composite material.

2. The modified waterborne polyurethane dispersion according to claim 1, characterized in that: The weight ratio of the polyurethane prepolymer to adipamide is 1:(0.6-0.8).

3. The modified waterborne polyurethane dispersion according to claim 1, characterized in that: The weight ratio of toluene diisocyanate and tridecafluorooctyl alcohol is 1:(0.4-0.6).

4. The modified waterborne polyurethane dispersion according to claim 1, characterized in that: The polyol is one or more of polyether diol, polycarbonate diol, and polyester diol, and the catalyst is one or more of dimethylcyclohexylamine, dibutyltin dilaurate, and N-ethylmorpholine.

5. The modified waterborne polyurethane dispersion according to claim 1, characterized in that: The neutralizing agent is one or more of ammonia and N,N-dimethylethanolamine, and the chain extender is one or more of ethylenediamine, hexamethylenediamine, and m-phenylenediamine.

6. A method for preparing a modified aqueous polyurethane dispersion as described in any one of claims 1-5, characterized in that, The process includes the following steps: mixing the composite material, polyol, catalyst, and polymerization inhibitor evenly, heating and maintaining the temperature to obtain a mixture, adding a chain extender, neutralizer, and water to the mixture, heating and maintaining the temperature to obtain a modified waterborne polyurethane dispersion.

7. The application of the modified waterborne polyurethane dispersion as described in any one of claims 1-5 in coatings, wherein the amount of the modified waterborne polyurethane dispersion added is 85-90 wt.

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