Yongkuan News
Yongkuan Chemical Newsletter-Issue 314
Release Date: 2019-12-16

experimental report § The truth about the yellow card

最近做UV濕氣雙重固化膠。客戶問:你的coating有黃卡嗎?競爭品都有!當我拿到競爭品的樣品,做成厚度100um的薄膜,直接用火焰去燒,結果是全部燒光光(圖1,2)。為何一個完全不阻燃的樹脂,塗在PCB板上面送測,就能拿到UL認證?答案很簡單:因為板子是阻燃的。100um的膠很快就被燒掉,板子本身燒不起來,就能夠通過UL的阻燃認證(圖3,4)。圖5是LOI實驗(Limiting oxygen index, 極限氧指數)。將氧氣/氮氣以不同的比例混合,通入試片周圍,再以火焰點燃。試片在氧氣比例越高的環境下才能持續燃燒,代表越難被引燃。圖6,7分別是是氧氣16%和20%的環境,前者會熄滅,後者會持續燃燒。競爭品在高於18%時就會被引燃,可見不具有阻燃性。這些實驗提醒我們,遇到認證需求時,能看清真正需要的東西,而不只是一張證書。
─ Author: Mr. Li Hui Xu
About Yongkuan § Warm December


Knowledge exchange § What are the types of single-liquid condensation RTV 1 Silicone?

Room temperature hardening silicone rubber can be divided into two types: condensation type and addition molding. Condensation type silicone rubber relies on moisture to carry out the hardening reaction, and it is mostly single-liquid type, commonly known as RTV1. The reaction of this resin is divided into two stages: firstly, the hydrolysis reaction with the moisture in the atmosphere releases a chemical substance to obtain a silanol functional group, and then undergoes a condensation reaction to solidify. RTV1 can be classified according to the chemical substances released: acidic (release acetic acid), neutral (release methanol, ethanol, acetone, oximes), basic (release amines). Although there are many types, the three most common types are deoxime, dealcohol and deacidification. Different types of RTV1 have slightly different properties, and the impact of released chemicals on parts and the environment must also be considered.

Biweekly strike § The beginning of life

When everyone is eating supper or sleeping until 2am in the unconscious, my first visit to Hehuanshan at night, the journey of strolling to see the scenery will begin soon. I felt both anticipated and frightened. Was it a pirate ship by mistake, or a pirate ship heading for treasure? The temperature at the foot of the mountain was about 11 degrees that night. I put on cold-proof clothes, put on the headlight and the instant rescue headscarf from Kai Ge, and started to go. The first peak is the North Peak of Hehuan. The sky above is hung with twinkling stars. I walked into the humble mountain climber, stepped on the ground with broken stones and wooden stairs, with a bright smile, step by step The beginning of the commemorative life of Baiyue is 0.1K. The steep stone slope along the way, and Jianzhu made me dare not relax for a moment, as long as I did not pay attention, the arrow bamboo will stab my ass, as if reminding me that the cliff on the right is to be careful. The mountains and the breeze of strong winds always make my hot and delicious ginger duck constantly appear in my mind.

It reached 4K at about 1.7am, and the sun that was about to wake up gradually brightened the mountain road. It turned out that visiting Hehuan Mountain at night was not terrible. The tranquility of the mountain made me devote myself to the embrace of nature. There was no light pollution in the starry sky, no hustle and bustle of the city, no mixed air. Walking in nature, watching the sun slowly from the sea of ​​clouds Rise, slowly blooming that simple but charming dawn. My first Baiyue was dedicated to Hehuan North Peak. The beautiful sunrise is a precious treasure from this journey, and it is really a worthwhile experience.
─ Author: Mr. Cheng Xian tour