High-flame-retardant waterborne polyurethane and preparation method thereof

Abstract

The invention provides waterborne polyurethane and a preparation method thereof. The preparation method comprises the following steps: letting phosphorus-free polyol react with specific phosphorus-containing polyol as shown in a formula (1), a phosphorus-containing stabilizer as shown in a formula (2) and polyisocyanate to form a prepolymer, emulsifying, and reacting with a phosphorus-containing chain extender to form the waterborne polyurethane. Phosphorus-containing groups are introduced into a soft segment of a polyurethane molecular chain by adopting phosphorus-containing polyol shown as the formula (1) to form a part of a waterborne polyurethane structure unit, so that the waterborne polyurethane structure unit has flame retardance under the condition that a flame retardant is not added; by adopting the phosphorus-containing stabilizer as shown in the formula (2), emulsification of phosphorus-containing waterborne polyurethane can be promoted, and the problem that emulsion is unstable after chain extension is solved, so that the problems that when a phosphorus-containing group is introduced into a polyurethane molecular structure, emulsification is difficult, and a waterbornedispersion liquid is difficult to form are solved. Moreover, phosphine-containing groups are introduced into the soft segment, the stabilizer and the chain extender of the waterborne polyurethane, sothat the flame retardance is greatly improved; and meanwhile, the binding power of the waterborne polyurethane is also enhanced by introducing a specific phosphorus-containing structure.

Description

technical field [0001] The invention relates to the field of organic polymers, in particular to a high flame-retardant waterborne polyurethane and a preparation method thereof. Background technique [0002] Water-based polyurethane is a block-type polymer green environmental protection material formed by alternating soft segments (polyester / polyether polyol) and rigid segments (isocyanate, small molecule chain extender). Waterborne polyurethane not only has the unique flexibility, friction resistance, low temperature resistance and good film-forming ability of polyurethane, but also uses water as a dispersant, has extremely low VOC emissions, reduces environmental pollution, and is widely used in adhesives, coatings , fabric finishing agent, leather finishing agent, paper and fiber surface treatment agent, water-based ink, papermaking and other fields. In the past few decades, waterborne polyurethane has received a lot of attention, so a lot of research has been done on it....

AI Technical Summary

Problems solved by technology

This type of additive flame retardant water-based polyurethane has a simple process, but the addition of flame retardant ingredients in the blend can easily reduce the stability of the water-based polyurethane emulsion and even lead to demulsification. At the same time, these flame retardants are difficult to stably disperse in the water-based polyurethane and easily form precipitation.

Although the liquid flame retardant will not produce precipitation, it will affect the film-forming properties of water-based polyurethane and the properties of the film formed after film formation, such as sticky film and insufficient bonding performance, etc. At the same time, the liquid flame retardant is easy to migrate out

Inorganic substances (such as magnesium hydroxide, aluminum hydroxide, etc.) filling modification generally need to add a large amount to achieve the flame retardant effect, but adding a large amount of inorganic substances will affect other properties of polyurethane

At present, the additive flame-retardant water-based polyurethane used for flame-retardant finishing of fabrics on the market has the disadvantages of opaque coating, large amount of flame retardants, poor washing resistance, and easy migration, which affects the appearance of fabrics.

In addition, the introduction of flame retardant components into the molecular structure of polyurethane can also improve the flame retardant performance, but when the flame retardant components increase, polyurethane is difficult to emulsify, and the formed aqueous dispersion is unstable, that is, waterborne polyurethane cannot be formed or has poor stability. Problems in construction and application, and affect the performance of performance (such as flame retardancy, adhesion, etc.)

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