Perpetual motion. Since the early days of the printing industry, it seems the act of printing, the inks used and the role of media in society are ever-changing. Over the last 20 years, this industry evolution has seen our media habits move from the physical to digital; our movies are streamed, our newspapers are read on tablets and our social interactions have become more impersonal.
This drive for change has also led to massive disruption in the retail space, where e-commerce is driving trends like augmented reality, buy online pick up in store (BOPIS) and subscription boxes; even the act of opening a box, or un-boxing, has evolved into an important moment of truth for consumer brands.
All this change has impacted the demands our industry places on printing inks and overprint varnish (OPV). Formulators are now looking for raw materials that:
- Enable a printer to compete in this crowded market with vibrant, high-quality inks and coatings that provide outstanding shelf aesthetics and on-brand e-commerce deliveries
- Support their economic need for operational efficiency
Over the last year or so, cost has remained a major challenge in our industry, as raw material fluctuations and margin depression have made growth an uphill battle. While brand owners value the high-quality printed content our industry produces, they have placed heavy pressure on printers and converters to keep costs low and quality high. This pressure has impacted all steps along the value chain.
Even removing raw material fluctuations from the equation, competitive industry dynamics mean customer bids can be won or lost by just pennies, with every producer or supplier focused on finding the most efficient and economical way to yield attractive printed products.
Compliance & Exposure
Brand owners, for whom we all work either directly or indirectly, are increasingly global in nature. They are conscious of the environmental and societal impacts of both the products they produce and the packaging they source. Many have made declarations of their goals surrounding the sustainability of their packaging; others have also focused on broad regulatory compliance and worker exposure.
As companies compete for a finite number of skilled workers, their job satisfaction has also become an important factor in retaining valuable talent, which is driving demand for low-VOC, easy-to-use solutions.
As demand for packaging grows, the ability to secure consistent, quality raw material supply can be a roadblock to harnessing industry strength. The drive for increasing packaging volumes, pushed by a variety of trends, like industry SKU proliferation and e-commerce, is placing additional pressure on printers and their suppliers to be as efficient and productive as possible.
Formulations Meet Need
The demands placed on printing inks are changing, translating into formulated inks that combine beautiful vibrant colors with increased resistance properties. To enhance versatility, resins and additives used in ink and coating formulations need to provide further ease of use through adaptability to a variety of applications and conditions.
Each component of an ink formulation has a role to play in the successful development of an end product that meets current market and customer needs in the most cost-effective way. High-quality styrene-acrylic resin solutions can be added to enhance gloss, holdout and resolubility of an ink. They are available in a range of viscosities from roughly 500 cp to 5,000 cP. As polymer solutions, their viscosity is generally determined by the molecular weight of the polymer, which can be a double-edged sword.
While higher molecular weight polymers can provide higher viscosity, and thus dilutability (cost-effectiveness), they can also have a lower contribution to gloss enhancement than lower molecular weight resins, as the dilution to application viscosity results in lower polymer solids. A resin solution that provides good dilution and high gloss captures both of these important benefits.
Colloidal solutions are often used to enhance dilutability as well. These products are generally higher in molecular weight than the polymers used in resin solutions, though lower than many polymer dispersions, and have mid-range acid values that allow them to have emulsion-like (low) viscosities at low pH, but solution-like (high) viscosities at high pH. The neutralized solutions are particularly good at holding viscosity as they are diluted, allowing them to have noticeable impact on viscosity even at very low percent solids levels. The thickening efficiency of the neutralized solution is determined in large part by molecular weight, with higher molecular weight polymers leading to higher viscosity solutions, which can take in more water.
The trade-off here is often in print quality, with higher molecular weight solutions tending to spatter and mist more than lower molecular weight solutions, or to have poorer transfer once diluted down to print viscosity. Gloss and clarity can also be negatively impacted with increased dilution; a colloid that can balance dilutability with printability and aesthetics is a useful product to have in one’s formulation toolbox.
Emulsions (or polymer dispersions made by the emulsion polymerization process) often comprise the largest portion of a water-based ink formulation. However, their physical form—high molecular weight chains, but in dispersed particles, so the chains don’t entangle in the liquid state—means that molecular weight is not necessarily the controlling factor in determining wet properties, such as dilution.
Instead, other factors allow emulsions to be supplied at viscosities anywhere from ~50 cP. to 2,500 cP. And, while they do not hold their viscosity as well as resin solutions or colloidal solutions when diluted, since they are typically used in larger amounts, they can wind up having a significant effect on the cost-in-use of an ink formulation. They also have strong influence on other properties of the inks, which can impact their ease of use and efficiency, such as: transfer, dry time during printing, viscosity, stability and storage for future use.
Emulsions also play a big role in determining the performance of the dried ink or OPV films that customers require, including gloss, clarity, as well as physical and chemical resistance properties.
Cost Savings & High Performance
Balancing performance, economics and safety is more important than ever to ink manufacturers, converters and brand owners. Efficient dilution profiles along with improvements in gloss, clarity, transfer and resistance properties allow innovative raw materials to provide both application cost savings and high performance, enabling ink makers, converters and brand owners to effectively compete in the current market environment.
This market continues to change and evolve. Through ingenuity and collaboration amongst its many active participants, we can ensure that inks and coatings enable this dynamic market to keep moving forward.