Everwide newsletter No.464

Experiment § Fast-Drying Screen Printing Adhesive

Screen printing is a long-established and widely applied printing technique. Its core principle lies in using a mesh screen as a stencil, allowing ink to pass through the mesh and transfer onto the surface of the substrate. This technique is commonly used in textile. printing, packaging printing, as well as the printing of instrument panels and printed circuit boards. The screen itself is a critical component in the printing process. Depending on industrial needs, different mesh fabrics and frame materials are selected and bonded together using adhesives to form the screen (Fig. 1). During fabrication, the mesh is first stretched to a specified tension value using a screen stretching machine. The frame is then placed on the base plate of the machine, where the adhesive is applied (Fig. 2). The two-component adhesive series NH205 can cure at room temperature and is suitable for bonding polyester mesh to metal frames, withstanding a tension exceeding 18 N/cm (Fig. 3). Among them, NH205-8 provides excellent solvent resistance, ensuring the screen remains intact during cleaning without delamination. NH205-16 and NH205-17 exhibit outstanding handling performance, with a surface-drying time of approximately 2–3 minutes, full hardening in about 10–15 minutes, and a pot life of over 3 hours. The viscosity of the mixed AB components changes gradually over time. Even after 5 hours, the viscosity remains around 2,000–2,500 cps, allowing smooth brush application without sagging (Fig. 4). Once fully cured, the adhesive layer withstands wiping with alcohols, ketones, aliphatic and aromatic hydrocarbons, as well as general cleaning agents. For further information or collaboration opportunities.                    

  -Author: Mr. Hsu, Ping-Cheng

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Activity § Protect Our Planet

We hosted a private screening of the documentary “Protect Our Planet”, inviting colleagues and their families to join. The film is Taiwan’s first ecological documentary to span both the Arctic and Antarctic, capturing the real impact of climate change on ecosystems. Studies indicate that by 2050, polar bears may extinction, and the loss of ice sheets will accelerate rising sea levels—posing serious threats to global ecosystems and human life. During the sharing session, a child was moved to tears while describing the starving polar bear collapsing from hunger. Let’s take action while there’s still time to save our planet—starting with reducing our carbon footprint!

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Knowledge § Principle of Polymer Annealing (1)

Polymers are often processed at high temperatures, and as they cool, the polymer chains move closer together, resulting in macroscopic shrinkage. An appropriate cooling rate allows the material to shrink uniformly, with the polymer chains arranging themselves in positions of minimum potential energy, where internal stress is minimized. However, if the cooling rate is too fast, temperature distribution becomes uneven. Different regions may shrink to varying degrees, or variations in geometry may cause differential shrinkage directions, both of which generate internal stresses. These internal stresses reduce the material’s strength and may be released unexpectedly, leading to deformation or cracking—issues that must be carefully managed in practical applications.

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Living § An Unexpected Encounter with a Caterpillar

One day, I discovered a plump green caterpillar munching on the leaves of a small potted plant at home. I asked my son, “Should we move it? Otherwise, after it lays eggs, our home might be full of insects.” My son replied, “Only butterflies lay eggs!” That simple remark made me realize I had been overthinking. From then on, I began to protect the little caterpillar, looking forward to its growth. I even moved the pot away from the fence to prevent birds from eating it. I watched its every move, day after day. But one day, little Green suddenly disappeared, leaving me a bit disappointed. A few days later, I found it again on the pot by the door, its body looking somewhat stiff. To my surprise, when I returned home from work, it had formed a chrysalis, hanging itself with silk. Concerned about wind, rain and birds, I moved the pot into the garage and continued to observe its transformation each day. One morning, it emerged from the chrysalis and flew away. I said to my son, “How ungrateful! We’ve cared for it all this time, and it leave without a word!” Later that afternoon, while the family was tidying the frangipani, we spotted a butterfly. Though we couldn’t be certain it was little Green, we all felt it was its transformed self. This brief encounter brought me a sense of small joys in everyday life, filling each day with anticipation, surprises, and change.                

                                                                                 —Author: Mrs. Yen Yu-Pin