WO2021077793A1

WO2021077793A1 - High-solid-content polyurethane emulsion and preparation method therefor

Info

Publication number: WO2021077793A1
Application number: PCT/CN2020/099208
Authority: WO
Inventors: 万晓波; 穆有炳
Original assignee: 江汉大学
Priority date: 2019-10-24
Filing date: 2020-06-30
Publication date: 2021-04-29
Also published as: CN110938186A

Abstract

Disclosed is a high-solid-content polyurethane emulsion and a preparation method therefor, belonging to the technical field of aqueous polyurethane. Components of the high-solid-content polyurethane emulsion comprise: polyether glycol, isocyanate and a chain extender of a polysulfonic acid ion group. The high-solid-content polyurethane emulsion and the preparation method therefor can effectively improve the surface charge density of micelles in the polyurethane emulsion with a lower amount of a chain extender, improve the solid content of the emulsion, and realize long-term stability of the polyurethane emulsion.

Description

High-solid polyurethane emulsion and preparation method thereof

Technical field

The invention relates to the technical field of waterborne polyurethane, in particular to a high-solid polyurethane emulsion and a preparation method thereof.

Background technique

The unique structural characteristics and excellent performance of polyurethane materials are gradually replacing traditional solvent-based polyurethane materials. In recent years, they have developed rapidly and are gradually being valued by government departments. At present, industrial fields such as coatings, adhesives, and synthetic leather are all vigorously advocating the use of environmentally friendly water-based materials.

Hydrophilic groups are the key to the emulsification of waterborne polyurethane in water, and its type and content have a significant impact on the appearance, particle size, solid content, viscosity, and stability of the waterborne polyurethane. The chain extension method is usually used to introduce hydrophilic groups into the main chain of polyurethane, so that the polyurethane has a certain degree of hydrophilic emulsification, so as to realize emulsification and dispersion in water and form a stable emulsion.

The waterborne polyurethane prepared by the hydrophilic chain extender can form a good emulsion, but since the chain extenders in the prior art only contain a single ionic group, the polyurethane emulsion obtained at a lower amount of chain extender has The low solid content greatly hinders the industrial application of waterborne polyurethane. In order to achieve the preparation of high-solid polyurethane emulsions, the amount of chain extender is generally increased, but this higher amount of hydrophilic groups will increase the water absorption in the later stage, thereby greatly reducing the performance of the formed polyurethane film.

Summary of the invention

The present invention provides a high-solid polyurethane emulsion and a preparation method thereof, which solves or partially solves the problem that the chain extenders in the prior art only contain a single ionic group, and the polyurethane emulsion obtained at a lower amount of chain extender The technical problem of low solid content.

In order to solve the above technical problems, the present invention provides a high-solid polyurethane emulsion. The components of the high-solid polyurethane emulsion include: polyether glycol, isocyanate and a chain extender of polysulfonic acid ion groups.

Further, the polyether glycol is polyethylene glycol, polypropylene glycol or polytetrahydrofuran glycol; the molecular weight of the polyethylene glycol is 1000-10000, the molecular weight of the polypropylene glycol is 1000-10000, and the poly(propylene glycol) has a molecular weight of 1000-10000. The molecular weight of tetrahydrofurandiol is 1000-3000.

Further, the isocyanate is toluene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, naphthalene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, hexamethylene A mixture of one or more of diisocyanates.

Further, the molar ratio of isocyanate groups to hydroxyl groups in the high solid polyurethane emulsion is 1:1.

Further, the chain extender structure of the polysulfonic acid ion group includes:

Further, the molar ratio of the sum of the hydroxyl group and the imino group to the isocyanate group in the high solid polyurethane emulsion is 1:1.

Based on the same inventive concept, the present application provides a method for preparing a high-solid polyurethane emulsion including the following steps: adding polyether diol into a reaction kettle; adding isocyanate to the polyether diol after dehydration, and adding isocyanate after dehydration. React at 80°C for 4-10 hours to form a first mixed solution; add a chain extender containing polysulfonic acid ion groups to the first mixed solution, and react at 50-80°C for 4-6 After hours, a second mixed solution is obtained; the second mixed solution is lowered to room temperature and emulsified in water under high-speed shear to obtain a high-solid polyurethane emulsion.

One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

Because the high-solid polyurethane emulsion is composed of polyether glycol, isocyanate and polysulfonic acid ion group chain extender, and polysulfonic acid ion group chain extender contains multiple sulfonic acid ion groups, it can At a lower amount of chain extender, it can effectively increase the surface charge density of micelles in the polyurethane emulsion, increase the solid content of the emulsion, and realize the long-term stability of the polyurethane emulsion.

Description of the drawings

Fig. 1 is a schematic flow diagram of a method for preparing a high-solid polyurethane emulsion provided by an embodiment of the present invention.

Detailed ways

An embodiment of the present invention provides a high-solid polyurethane emulsion. The components of the high-solid polyurethane emulsion include: polyether glycol, isocyanate, and a chain extender of polysulfonic acid ion groups.

The specific embodiment of the application is because the high-solid polyurethane emulsion is composed of polyether glycol, isocyanate and polysulfonic acid ion group chain extender, and the polysulfonic acid ion group chain extender contains multiple sulfonic acids Ionic groups can effectively increase the surface charge density of micelles in the polyurethane emulsion at a lower amount of chain extender, increase the solid content of the emulsion, and realize the long-term stability of the polyurethane emulsion.

Specifically, the polyether glycol is polyethylene glycol, polypropylene glycol or polytetrahydrofuran glycol. The molecular weight of polyethylene glycol is 1000-10000, the molecular weight of polypropylene glycol is 1000-10000, and the molecular weight of polytetrahydrofuran glycol is 1000-3000.

Specifically, the isocyanate is toluene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, naphthalene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate A mixture of one or more of them.

Specifically, the molar ratio of isocyanate groups to hydroxyl groups in the high-solid polyurethane emulsion is 1:1.

The structure of the chain extender of polysulfonic acid ion groups includes: No. I chain extender of polysulfonic acid ion groups.

The chain extender structure of polysulfonic acid ion group includes: No. II chain extender of polysulfonic acid ion group.

The chain extender structure of the polysulfonic acid ion group includes: the chain extender of the polysulfonic acid ion group III.

Since there are only hydroxyl groups in the system, the feeding ratio is controlled to a molar ratio of isocyanate groups to hydroxyl groups of 1:1.

Specifically, the molar ratio of the sum of the hydroxyl group and the imino group to the isocyanate group in the high solid polyurethane emulsion is 1:1.

The chain extender structure of the polysulfonic acid ion group includes: the chain extender of the polysulfonic acid ion group No. IV.

Since the system contains both hydroxyl groups (on the polyol) and imino groups (on the chain extender), the feed ratio is controlled so that the molar ratio of the sum of the hydroxyl group and the imino group to the isocyanate group is 1:1.

Referring to Fig. 1, based on the same inventive concept, this application also provides a method for preparing a high-solid polyurethane emulsion, which includes the following steps:

Step 1. Add polyether glycol into the reaction kettle.

Step 2: After the polyether glycol is dehydrated, isocyanate is added, and reacted at 50-80° C. for 4-10 hours to form a first mixed solution.

Step 3: Add a chain extender containing polysulfonic acid ion groups to the first mixed solution, and react at 50-80° C. for 4-6 hours to obtain a second mixed solution.

Step 4. Lower the second mixed solution to room temperature and emulsify it in water under high-speed shear to obtain a high-solid polyurethane emulsion.

The preparation method of the present application is simple, easy to scale up the operation process and realize industrialized production. Since the chain extender of the polysulfonic acid ionic group used contains multiple ionic groups, the long-term stability of the water-based polyurethane emulsion can be achieved at a lower amount of chain extender, which can effectively reduce the affinity of the material itself after the polyurethane emulsion is cured. Water may cause the risk of performance degradation due to water absorption in the later stage. At the same time, due to the increase in the number of sulfonic acid ion groups, the surface charge of the micelles in the waterborne polyurethane emulsion can be increased, and the solid content of the emulsion can be increased. It is expected to break the technical bottleneck of the current low solid content of waterborne polyurethane emulsions. The synthetic chain extender provides a new way to synthesize waterborne polyurethane materials.

In order to introduce the present invention more clearly, specific embodiments of the present invention will be introduced below.

Example 1:

Add 10 g of polyethylene glycol (molecular weight 1000) into the reaction kettle, add 2.09 g of toluene diisocyanate after dehydration, and react at 50° C. for 4 hours.

Adding No. I polysulfonic acid ionic group chain extender (M=Na, x=1) 0.83g, react at 50℃ for 6h, reduce to room temperature, emulsify in water under high-speed shear to obtain polyurethane emulsion, the highest solid content can be Up to 75%.

Example 2:

Add 10 g of polyethylene glycol (molecular weight 10000) to the reaction kettle, add 0.26 g of toluene diisocyanate after dehydration, and react at 80°C for 8 hours.

Add chain extender (M=Na, x=5) of No. I polysulfonic acid ion group, 0.24g, react at 80℃ for 4h, reduce to room temperature, emulsify in water under high-speed shear to obtain polyurethane emulsion, the highest solid content can be Up to 65%.

Example 3:

Add 10 g of polyethylene glycol (molecular weight 3000) into the reaction kettle, add 0.70 g of toluene diisocyanate after dehydration, and react at 60°C for 6 hours.

Adding No. I polysulfonic acid ion group chain extender (M=Na, x=3) 0.46g, reacting at 60℃ for 4h, cooling to room temperature, emulsifying in water under high-speed shear to obtain polyurethane emulsion, the highest solid content can be Up to 65%.

Example 4:

Add 10 g of polypropylene glycol (molecular weight 1000) into the reaction kettle, add 2.66 g of isophorone diisocyanate after dehydration, and react at 60° C. for 6 hours.

Adding No. II polysulfonic acid ion group chain extender (M=Na, x=0) 0.98g, reacting at 60℃ for 4h, cooling to room temperature, emulsifying in water under high-speed shear to obtain polyurethane emulsion, the highest solid content can be Up to 72%.

Example 5:

Add 10 g of polypropylene glycol (molecular weight 10000) into the reaction kettle, add 0.26 g of toluene diisocyanate after dehydration, and react at 80°C for 10 hours.

Add 0.25g of chain extender (M=Na, x=1) of No. II polysulfonic acid ion group, react at 80℃ for 5h, cool to room temperature, emulsify in water under high-speed shear to obtain polyurethane emulsion, the highest solid content can be Up to 64%.

Example 6:

Add 10 g of polypropylene glycol (with a molecular weight of 2000) to the reaction kettle, add 1.31 g of toluene diisocyanate after dehydration, and react at 60° C. for 6 hours.

Adding No. II polysulfonic acid ionic group chain extender (M=Na, x=4) 1.36g, react at 60℃ for 4h, cool to room temperature, emulsify in water under high-speed shear to obtain polyurethane emulsion, the highest solid content can be Up to 76%.

Example 7:

Add 10g of polytetrahydrofurandiol (molecular weight 1000) into the reaction kettle, add 2.09g of toluene diisocyanate after dehydration, and react at 60°C for 6h.

Adding No. III polysulfonic acid ionic group chain extender (M=K, x=0) 1.0g, react at 60℃ for 6h, cool to room temperature, emulsify in water under high-speed shear to obtain polyurethane emulsion, the highest solid content can be Up to 72%.

Example 8:

Add 10g of polytetrahydrofurandiol (molecular weight 3000) into the reaction kettle, add 0.87g of toluene diisocyanate after dehydration, and react at 80°C for 6h.

Adding No. III polysulfonic acid ionic group chain extender (M=K, x=1) 0.91g, react at 80℃ for 4h, reduce to room temperature, emulsify in water under high-speed shear to obtain polyurethane emulsion, the highest solid content can be Up to 70%.

Example 9:

Add 10g of polytetrahydrofurandiol (molecular weight 2000) into the reaction kettle, add 1.04g of toluene diisocyanate after dehydration, and react at 70°C for 6h.

Adding No. III polysulfonic acid ion group chain extender (M=K, x=4) 0.59g, react at 70℃ for 4h, cool to room temperature, emulsify in water under high-speed shear to obtain polyurethane emulsion, the highest solid content can be Up to 68%.

Example 10:

Add 10 g of polypropylene glycol (with a molecular weight of 2000) to the reaction kettle, add 1.04 g of toluene diisocyanate after dehydration, and react at 70° C. for 6 hours.

Adding No. IV polysulfonic acid ionic group chain extender (M=Na, x=1, m=0) 0.68g, react at 70°C for 5h, cool to room temperature, emulsify in water under high-speed shear to obtain polyurethane emulsion, The solid content can reach up to 70%.

Example 11:

Add 10 g of polypropylene glycol (with a molecular weight of 2000) to the reaction kettle, add 1.26 g of hexamethylene diisocyanate after dehydration, and react at 80° C. for 6 hours.

Adding No. IV polysulfonic acid ion group chain extender (M=Na, x=3, m=1) 1.81g, reacting at 80°C for 4h, cooling to room temperature, emulsifying in water under high-speed shear to obtain polyurethane emulsion, The solid content can reach up to 73%.

Example 12:

Adding No. IV polysulfonic acid ion group chain extender (M=Na, x=5, m=4) 0.79g, reacting at 80°C for 4h, cooling to room temperature, emulsifying in water under high-speed shear to obtain polyurethane emulsion, The solid content can reach up to 67%.

Example 13:

Adding No. IV polysulfonic acid ion group chain extender (M=Na, x=5, m=4) 0.4g and monosulfonic acid ion group chain extender N,N-bis(2-hydroxyethyl) Sodium-2-aminoethanesulfonate 0.24g, reacted at 80°C for 4h, cooled to room temperature, and emulsified in water under high-speed shear to obtain a polyurethane emulsion with a solid content of up to 66%.

In this application, a chain extender containing polysulfonic acid ion groups is used to synthesize waterborne polyurethane containing polysulfonic acid ion groups by means of chain extension, and the introduction of polysulfonic acid ion groups is used to improve the solid content and storage stability of the emulsion.

Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be implemented Modifications or equivalent replacements without departing from the spirit and scope of the technical solutions of the present invention should be covered by the scope of the claims of the present invention.

Claims

A high-solid polyurethane emulsion is characterized in that the components of the high-solid polyurethane emulsion include: polyether glycol, isocyanate and a chain extender of polysulfonic acid ion groups.
The high solid polyurethane emulsion according to claim 1, characterized in that:

The polyether glycol is polyethylene glycol, polypropylene glycol or polytetrahydrofuran glycol;

The molecular weight of the polyethylene glycol is 1000-10000, the molecular weight of the polypropylene glycol is 1000-10000, and the molecular weight of the polytetrahydrofuran glycol is 1000-3000.
The high solid polyurethane emulsion according to claim 1, characterized in that:

The isocyanate is toluene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, naphthalene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate A mixture of one or more of them.
The high solid polyurethane emulsion according to claim 1, characterized in that:

The molar ratio of isocyanate groups to hydroxyl groups in the high solid polyurethane emulsion is 1:1.
The high solid polyurethane emulsion of claim 4, wherein the chain extender structure of the polysulfonic acid ion group comprises:
The high-solid polyurethane emulsion of claim 1, wherein the chain extender structure of the polysulfonic acid ion group comprises:
The high-solid polyurethane emulsion of claim 1, wherein the chain extender structure of the polysulfonic acid ion group comprises:
The high solid polyurethane emulsion according to claim 1, characterized in that:

The molar ratio of the sum of hydroxyl groups and imino groups to isocyanate groups in the high solid polyurethane emulsion is 1:1.
The high-solid polyurethane emulsion according to claim 8, wherein the chain extender structure of the polysulfonic acid ion group comprises:
A method for preparing a high-solid polyurethane emulsion for preparing the high-solid polyurethane emulsion according to any one of claims 1-9, wherein the method for preparing the high-solid polyurethane emulsion comprises the following steps:

Add polyether glycol into the reaction kettle;

The polyether glycol is dehydrated and added with isocyanate, and reacted at 50-80°C for 4-10 hours to form a first mixed solution;

Adding a chain extender containing polysulfonic acid ion groups to the first mixed solution, and reacting at 50-80°C for 4-6 hours to obtain a second mixed solution;

The second mixed solution is lowered to room temperature and emulsified in water under high-speed shear to obtain a high-solid polyurethane emulsion.