Waterborne polyurethane additives are mainly divided into which categories according to function
01
Stabilising additives are substances that enhance the stability of waterborne polyurethane materials. Waterborne polyurethane materials, the bigger defect is its poor aging resistance, which hinders the use and development of the product, therefore, the exploration of the aging resistance of waterborne polyurethane materials is throughout the research and development of waterborne polyurethane materials. Therefore, the problem of anti-aging of waterborne polyurethane materials must be treated correctly, in fact, it is necessary to pay attention to the research of waterborne polyurethane stabilising additives.
02
Improvement of mechanical properties additives This kind of additives is a substance to enhance a particular physical property of waterborne polyurethane materials. Waterborne polyurethane material itself is not any performance is so significant, the only additives will have the value of use.
03
Improvement of processing performance additives waterborne polyurethane materials have many characteristics of the material itself, such as viscosity, which makes the processing becomes more complicated, therefore, in the waterborne polyurethane processing and use, improve its processing performance of the additives is more and more critical.
04
Improvement of surface properties and appearance additives make waterborne polyurethane have antistatic effect of antistatic agent, whitening agent for coating, sliding agent and so on.
05
Flame-retardant additives make the material incombustible or prevent the material from burning.
06
Improvement of flow and rheological performance additives waterborne polyurethane materials based on the differences in the application of the object, the requirements are not the same. Such as wood adhesive due to the porous nature of the material, the viscosity of the waterborne polyurethane adhesive is required to be large enough to avoid the glue to penetrate into the internal structure of the wood and it is difficult to ensure the amount of sizing, at this time, it is necessary to add thickening agent.
Waterborne polyurethane is a new type of polyurethane system that uses water instead of organic solvents as the dispersing medium, with the advantages of non-combustibility, low odour, non-pollution, energy saving, easy to operate and process, etc. It is widely used as adhesive and coating.
Polyurethane chain extender is a key additive in the production of polyurethane products. In the polyurethane manufacturing industry, in addition to extending the polyurethane molecular chain or forming a network structure, chain extenders can also be used to adjust the polyurethane molecular chain, which can play a role in the production of polyurethane to improve the stability of the product, improve the stability of the tear strength, heat resistance, hardness, abrasion resistance, rebound, compression deformation and other physical properties of the indexes to promote the role.
Polyurethane chain extenders are usually small molecule compounds containing hydroxyl or amino groups, mainly including aliphatic diols, aromatic diols and aromatic diamines, etc., of which aromatic diamines are the mainstream products in the polyurethane chain extender market. Polyol chain extenders can be used in polyurethane foam, polyurethane elastomers, polyurethane adhesives and so on. Diamine chain extenders can be applied to polyurethane coatings, polyurethane adhesives and polyurethane elastomers. Commonly used alcohol and amine chain extenders include ethanolamine, diethanolamine, triethanolamine, etc., which can be applied to polyurethane soft foam, hard foam and elastomers.
The chain extension reaction of waterborne polyurethane is affected by a variety of factors such as prepolymer, chain extender, reaction temperature, reaction time and so on. Since the main basis of waterborne polyurethane chain extension reaction is waterborne polyurethane prepolymer. The average molecular weight and structure of the prepolymer have an important influence on the chain extension reaction. The larger the molecular weight of the prepolymer is, the more reactive it is to the chain extender and the faster the reaction rate is. Secondly, the more hydroxyl groups the chain extender contains, the more obvious the chain extension effect, but too many may also lead to the toughness and strength of waterborne polyurethane decrease. The chain extension reaction is generally carried out at room temperature, and the reaction time should not be too long or too short.
