Journey 1995:Non-Stop

Chapter 315 The future is promising
Song Zhiyuan's involvement is part of Yan Hui's plan.

Although the synthesis of single-component polyurethane was unsuccessful, judging from Chen Jian's work style, success is very likely. Yan Hui can handle a few detours!
As soon as Song Zhiyuan arrived, Yan Hui took him to the processing plant and had him work with Liu Jianlei.

Yan Hui really made the right choice in hiring Liu Jianlei. During his time as deputy director of the processing plant, he was even more responsible than Dai Zhongwei. He worked with the workers every day, and over this long period of time, Liu Jianlei has become very familiar with the processing business.

Wood processing isn't a chemical experiment; these CNC machines aren't difficult to learn once you get the hang of them. With Liu Jianlei here, Yan Hui is very reassured about safety, because Liu Jianlei is a reliable person.

Speaking of this, Yan Hui has to complain about some of his father's issues.

Although both were "deputy factory directors," my father was far inferior to Liu Jianlei.

My father came to the factory in March and has been busy there every day, but he mostly just wanders around and doesn't really work hard. Given his position, no one dares to say anything. In short, my father has it much easier than Yan Hui.
In Jinan, my father is the one who's adapted the best. My mother and grandmother are finding it a bit difficult; they don't speak the language well and don't have many friends. My father is different. He's learned all the local card and board games and plays them every day with great enthusiasm.

After Song Zhiyuan arrived, his father pretended to work hard for a few days, but then he went off to do something else.

In Yan Hui's plan, Liu Jianlei wasn't in the timber processing business, but rather to supervise the construction. If all went smoothly and the chemical plant could be built next year, Yan Hui definitely wouldn't be able to oversee it alone, and he would need Liu Jianlei to supervise the construction. Yan Hui didn't trust anyone else to do this job.

At the end of the month, Chen Jian, having had a good rest, returned to Jinan with his wife. Yan Hui invited them and Song Zhiyuan to have dinner together.

Chen Jian hadn't expected Song Zhiyuan to come; he quite liked Song Zhiyuan. Song Zhiyuan had a very solid academic foundation. In organic synthesis, he had basically completed the main knowledge learning during his undergraduate years, and during his graduate studies, he mainly focused on research and experiments. In other words, in terms of pure theory, Song Zhiyuan was absolutely qualified.

It could even be said that, aside from polyurethane experiments, there are other areas where Song Zhiyuan may have knowledge that even Chen Jian had forgotten.

"The addition polymerization reaction starts with isocyanate reacting with hydroxyl groups to form urethane groups, then isocyanate reacting with water to form urea groups, then reacting with amine groups to form substituted urea groups, and finally reacting with carboxyl groups to form amide groups. We have been able to reproduce this process many times, and the prepolymer is already considered mature." Chen Jian explained the general progress to Song Zhiyuan.

“Chen Jian’s experiments were very meticulous; he was able to reproduce all three types of prepolymers (ABC) stably,” explained Liu Wei, Chen Jian’s wife. “My doctoral dissertation was about type C prepolymers.” (The term “ABC” refers to prepolymers from 20 years ago; due to technological advancements, there are now too many types of prepolymers to use numbered lists anymore.)
“If I remember correctly, the molecular weights of type B prepolymer and type C prepolymer are the same,” Song Zhiyuan said after a moment’s thought.

“Your foundation is quite solid, that’s right. It’s just that the free isocyanate content is different. The molecular weight is the same, 2522, but the free isocyanate content of the C-type prepolymer reaches 11%. Generally speaking, it’s difficult to operate when this value reaches 10%, because the storage period is too short.” Chen Jian nodded in satisfaction.

Simply put, the goal is to synthesize this prepolymer into a single-component polyurethane, increasing the molecular weight from several thousand to tens of thousands—that's roughly the process. Chen Jian certainly needs assistants. He had some junior master's students who came before, but they all left after a few months of hardship. Since Dr. Luo left, only Chen Jian and a few workers remain.

"So which approach are we using now? Are we working with polyether-type prepolymers?" Song Zhiyuan asked.

"Yes, polyether-type prepolymers are flexible, hydrolysis-resistant, and low-temperature resistant. Although they are not as resistant to high temperatures as polyester-type prepolymers, our target applications are automotive glass adhesives, etc., and these applications usually have higher requirements for low temperatures," Chen Jian explained patiently.

Back in Northeast China, Yan Hui had heard that his fourth uncle's car cost over 200,000 yuan, which told him that the automotive industry was extremely profitable, with the entire supply chain being very lucrative. Cars sometimes face temperatures as low as -20 or -30 degrees Celsius, but parts like the glass don't encounter high-temperature environments. In such cases, polyether-type prepolymers are clearly better than polyester-type prepolymers.

"Could you tell me about the specific production process? It feels different from the lab," Song Zhiyuan asked.

"The polyether is heated to 110 degrees Celsius in a vacuum environment to dehydrate it, and the moisture content must be controlled below 15,000. Then, it is added to the reactor along with an excess of isocyanate. Under nitrogen protection, it is reacted at 75 degrees Celsius for three hours, with regular monitoring. Then, phthalate, filler, catalyst, and stabilizer are added. You will understand the specific process if you follow along with me. The biggest problem now is that the -NCO groups of the prepolymer will react with water in the air to produce unstable carbamic acid. This substance will automatically decompose to generate carbon dioxide. Once this carbon dioxide is generated, bubbles will appear. This is the core problem that we need to solve right now."

"So, would simply addressing the moisture content in the air solve the problem?" Song Zhiyuan frowned slightly. His frown stemmed from his disbelief that the issue could be so straightforward.

"It's not just about the presence of water in the air; the entire process is strictly controlled. In my experiments, I've found that reducing the NCO content in the prepolymer can decrease the amount of carbon dioxide produced. Alternatively, using HDI trimer for the reaction, which is slower, allows time for carbon dioxide to escape. Carbon dioxide will definitely be produced; it's unavoidable."

"Could we add some silicone-based defoamer?"

“Well… my senior had the same idea before, but that also caused particles to form.” Chen Jian sighed. “Actually, this problem isn’t difficult to solve. The most advanced solution internationally uses silane-terminated polyurethane. This product has silane groups that can directly hydrolyze and condense with water, without producing any gas bubbles. But… we don’t have this technical solution; we have no idea what to do.”

"I understand. In short, I will definitely study hard." Song Zhiyuan nodded.

The conversation with the group broadened Yan Hui's horizons considerably. Before, he had only noticed the difficulties here and there, but he had no idea where the problems lay.

Because of Yan Hui's limited skills, he couldn't even ask a decent question. Now that Song Zhiyuan was here, that familiar feeling returned. After the group talked, although Yan Hui still didn't understand everything, he learned about the project's progress and other details.
Never mind, the future looks promising anyway.

(The author's academic level is limited, and if there are any problems with the expression, I hope that professionals will not hesitate to point them out.)
(End of this chapter)