Everwide Newsletter-No.9

The durometer is used to test the hardness of resin after hardening, which is divided into two test methods: Shore A and Shore D. Test method: Fix the pressing surface (pressure gauge surface) of the durometer with both hands and press it vertically on the plane of the resin at a certain speed from right above the resin. When the pressing surface of the durometer is close to the resin immediately after contact, read the indicated hardness value, repeat this test method several times, and obtain the average value, which is the hardness.

Shore A is suitable for: general or synthetic rubber, soft plastic tires, rubber rollers, etc.

Shore D is suitable for: hard rubber, plastic, and hard rubber, when it exceeds ShoreA90.

*1 N-type/single needle type; G-type/double-needle type. *2 Some variable factors during the test, such as temperature, humidity and resin shape of the operating environment, etc., will affect the test results

Due to the influence of the surrounding environment, metal is easy to corrode and destroy the original characteristics of the metal. In order to reduce the phenomenon of metal corrosion and maintain the service characteristics of the metal, there is a need for surface treatment agents. The metal surface treatment agent has three main functions: 1. Change the state of the metal surface and form a protective film so that the metal is not easy to corrode. ②The film formed by the metal surface treatment agent on the metal surface has quite a good compatibility with the epoxy resin adhesive. It will not affect the bonding strength of the epoxy resin. ③ Improve moisture resistance and bonding strength, effectively slowing down the decline of bonding strength in the environmental test of high temperature and high humidity.

In the following experiments, JB782 was used as epoxy resin adhesive, the hardening condition was 150oC/30min, the adhesive area was 25.4mm×6mm, and the material was an aluminum sheet.

Fig. 1: The photo of the aluminum sheet without surface treatment and the surface corrosion after the high temperature and high humidity experiment.

Figure 2: The photo of aluminum sheet impregnated with JB935 for surface treatment, high temperature, and high humidity experiment.

According to the Arenis equation, the reaction rate (R) is proportional to the activation energy (Ea) of the reaction as follows: R µ Exp(-Ea/RT)

From this relationship, it can be inferred that the temperature rises by 10oC, and the reaction speed is about twice the original. Conversely, when the temperature drops by 10oC, the reaction rate is about 1/2 of the original.

The above relationship is generally applicable to inhomogeneous systems. However, in some single-liquid systems, specific temperature ranges may not be applicable when the melting or dissociation of the temperature-sensitive hardener is involved.

GM005 photo hardening resin, under the irradiation of ultraviolet light (365nm) or visible light (436nm), reacts rapidly and forms, and the hardened resin has the properties of toughness resistance to cold and thermal shock, etc. Due to the medium to high viscosity characteristics, the substrate does not slip after gluing. This product is especially suitable for fixing and bonding between glass and metal, and the bonding force is also relatively stable for difficult-to-bond alloy metals.

I once went to a winery in Xinyi Township. The owner said, "The technique of winemaking and the ripeness and sweetness of the grapes in the past year will affect the quality of this batch of wine in the future." It said that all red wine is unique because of the quality of the feed, the degree of fermentation, and the temperature of storage. They make wine without instrument analysis and reaction conditions, and the only way is to taste it with the mouth. As a result, the wine of a particular year is spicier, and the wine of a certain year is sweet. Students who study chemistry always want to use the "scientific method" to solve problems. Foraged wine, the horizontal axis is time, so let's look at the accelerated experiment of the finished product, which is to simulate the accelerated experiment with the temperature shock QUV. I am genius to say that the wine brewed today does not need to be kept for five years. If an accelerated experiment is used for five months, the composition and chemical changes of the wine will be similar to five years? Of course, if everyone had been very talented, it would not be unusual for a century-old wine. What about us? What will the future look like when you are twenty to thirty years old? What about the company? What do you see in the future from one to five years? What about Earth? Looking to the future from two hundred years? Ask more how less why. When a man thinks, God laughs. Are you interested in drinking wine?

─Author: Mr. Hui-xu, Li, R&D Engineer, Everwide Chemical