New sustainable polymers: a greener future for commercial inkjet printing

当前，世界正处于一个关键时刻。可持续材料、清洁能源、气候变化等亟待关注的问题层出不穷。科学界有能力应对这些挑战，包括承担维护地球的责任。随着食品包装行业的持续发展趋势，包括批量生产、工业4.0和制造数字化，现在对生产灵活性和提高产品可追溯性有了需求。现在，消费者、品牌所有者、政府和非政府组织（ngo）也对环境可持续性提出了很高的要求，他们要求产品减轻环境负担。数字印刷技术被视为一种具有成本效益的印刷可变数据和产品品牌的方式，因此正在取代传统的印刷方法。喷墨印刷是一种普遍用于在各种吸收性介质（包括食品包装）上印刷图像和文字的技术。通常用于标识标志印刷的溶剂型油墨配方，由于挥发性有机化合物（VOCs）的存在，具有良好的耐久性和快速干燥。由于挥发性有机化合物对健康和环境都有害，因此市场希望逐步停止使用它们。水性油墨涉及到水的使用，这是现成的和无害的环境。然而，在处理水性油墨时，还有其他问题需要克服，包括干燥时间，耐久性（不使用底漆和清漆）以及对特定（疏水）材料的粘附性。由此可以确定，迫切需要一种适合在食品包装上印刷的无voc喷墨配方，它结合了UV和溶剂油墨的坚固性和快速干燥特性以及水性技术的环保证书。该项目将通过开发可从水中沉积的新型可固化材料来解决这一需求。它将建立在多米诺印刷科学公司和阿斯顿之前的合作基础上，开发一种新的紫外线固化聚合物技术平台。最近的研究揭示了使用可逆加成-破碎链转移（RAFT）聚合来创建具有所需两亲性特性的嵌段共聚物。RAFT是一种通用且强大的技术，可以控制许多其他特性，包括分子结构、摩尔质量、质量分散和链端功能。这些合成的聚合物添加剂是水性油墨配方的一大补充，成功地增强了它们的特性，并使热交联成为可能。目前的研究是合成UV可触发嵌段共聚物，这将减少在交联过程中加热所需的能量。该研究项目围绕着下一步考虑油墨配方的内容及其可能造成的环境破坏。在聚合过程中使用从我们的环境/可再生资源（例如植物油）而不是从石油中容易获得的单体，将大大进一步提高水性油墨配方的可持续性。最终，研究创造一种新的水性油墨配方有可能产生现实世界的影响；完全不去理会那些会导致环境恶化的刺激性化学品的使用，将会给我们生活的世界带来革命性的变化。

Currently, the world is at a critical point. There are endless issues that require urgent attention such as sustainable materials, clean energy, and climate change. The scientific community has the ability to address these challenges, including the responsibility for the maintenance of our planet.With ongoing trends in the food packaging industry, including batch-of-one operations, Industry 4.0 and the digitisation of manufacturing, there is now a demand for production flexibility and improved product traceability. Environmental sustainability is now also highly demanded from consumers, brand owners, governments and non-government organizations (NGOs), where products with a reduced environmental burden are required. Digital printing techniques are seen as a cost-effective way of printing variable data and product branding and, as such, are displacing traditional printing methods. Inkjet printing is the technology used universally to print images and text on a range of absorbent media (including food packaging). Solvent based ink formulations, commonly used in the printing of identification marks, have good durability and dry quickly due to the presence of volatile organic compounds (VOCs). As VOCs are hazardous to both health and the environment, there is a market desire to transition away from their use. Aqueous based inks involve the use of water, which is readily available and non-harmful to the environment. However, there are additional problems to overcome when dealing with water-based inks including drying time, durability (without the use of primers and varnishes) and adherence to specific (hydrophobic) materials. From this it can be established that there is a pressing need for a VOC-free inkjet formulations suitable for printing onto food packaging, which combines the robustness and fast drying properties of UV and solvent inks with the environmental credentials of aqueous technologies. This project will address this need by developing novel, curable materials which can be deposited from water. It will build on a previous collaboration between Domino Printing Sciences and Aston to develop a new UV-curable polymer technology platform. This recent research has unveiled the use of reversible addition-fragmentation chain transfer (RAFT) polymerisation to create block copolymers with the desired amphiphilic characteristics. RAFT is a versatile and robust technique that allows for control over many other characteristics including molecular architecture, molar mass, mass dispersity and chain-end functionality. These synthesised polymer additives make a great addition to aqueous ink formulations, successfully enhancing their characteristics as well as enabling thermal crosslinking. Current research is to synthesise UV triggerable block copolymers, which would reduce the energy required for heating during the crosslinking process. This research project revolves around the next step of considering the contents of the ink formulation and the environmental damage it may cause. Using monomers in the polymerisation process that are readily available from our environment/renewable resources (e.g plant oils) rather than from petroleum would significantly further increase the sustainability of the aqueous ink formulations. Ultimately, researching to create a new water-based ink formulation has the potential to make real-world impact; completely disregarding the use of harsh chemicals that contribute to the deterioration of our environment would revolutionise the world in which we live in.