UV curable urethane acrylate resin - The building blocks’ impact on the properties

Abstract

For a coating to withstand scratches, and have good abrasion resistance are extra important for some applications. PVC floors for example are often exposed to extensive wear, and it is therefore important to coat it with a coating that can withstand the hard use.

One type of UV coating that have good scratch and abrasion resistance is a coating containing urethane acrylate resin. This type of resin is a part of a growing market and it is therefore of great interest to gather as much knowledge possible about how the molecular structure of urethane acrylate affects different chemical and physical properties of the finished coating.

In the present study the experiments were carried out based on a experimental design to determine the effect the type of polyol in the polyester, the molecular weight of the polyester, the type of isocyanate used, and the acrylate functionality of the polymer, have on the chemical and mechanical properties, such as impact strength, chemical and scratch resistance.

By synthezising and evaluating the created resins it was revealed that the cross-link density, and flexibility of the polymer have large impact on the chemical and physical properties, and that the properties can be tuned depending on what is desirable, but that some properties counteracts each other. For future work the effect of reactive diluents needs to be evaluated.

Popular Abstract

The paint and coating industry is a huge industry that is often forgotten in real life. It is more common that you wonder where the package material for different foods, and everyday stuff come from than all the paints and coatings that are everywhere in today's society.

Depending on what kind of application the coating is used for (wall paint, coatings for tables etc.) it have special requirements on the properties. What most people do not know is that most of the coatings properties comes from the resins, polymers made from smaller building blocks much like a chain, that builds up the coating.

One type of resins that are becoming more and more popular in industrial coatings are ultraviolet (UV) curable resins, where one example are urethane acrylate. These type of resins have several advantages over traditional resins that contains solvents or water. Many traditional coatings forms a solid film through drying (evaporation of water or solvents), and this means that not only are solvents/water released into the air, but industries that uses these coatings have large ovens and heating lamp to speed up the drying process of the coatings, resulting in high energy consumption.

UV curable coatings however forms a solid film almost immediately when exposed to UV-light. During this curing, the polymers are linked together to form a huge network, or linked polymer chains. This means that not only does a solid film form faster, it also means that the production rate increases, less energy is needed for drying and no solvents (or such) are released into the air.

UV curable resins often give high scratch, and abrasion resistance, which means that it can be used on surfaces that needs to withstand hard use, like floors and office tables.

However the chemical and physical properties of the resin and the solid film are dependent on the building blocks of the polymer, which was investigated during this project.

It resulted in that the most important properties of the polymer was the cross-link density which is how tight the network of polymer chains become, and the flexibility of the polymer. By having a high cross-link density, the film becomes very hard, scratch resistant, and can withstand harsh chemicals and stains. This is important for tables and floors. However if an application asks for more flexibility, for example softer floors and plastics, the cross-link density must be reduced so the coating won't crack.

By understanding how different build blocks affects the different properties of the resin, it will create an opportunity to produce a resin with the exact properties needed for just that application.

• author: Moritz, Petra
• supervisor: Marcel Ollila; Baozhong Zhang
• organization: Centre for Analysis and Synthesis
• alternative title: The future of coatings: the process of developing the next generation
• course: KASM15 20191
• year: 2019
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Polymer technology, Polymerteknologi
• language: English
• id: 8987763
• date added to LUP: 2019-07-04 16:42:38
• date last changed: 2019-07-04 16:42:38