Effect of Glass Fiber Reinforced PA66 on Moisture Absorption of Connector

The most promising market area for connectors is the automobile field. With the rapid development of economy, automobile has become one of the indispensable means of transportation for every household, so the future development of automobile is particularly important for people's life. The broad market demand requires good product quality to ensure, which means that the connectors used in the automotive field are more stringent than those in other fields, and excellent product quality and good product performance are required to adapt to and challenge the harsh use environment. Therefore, we should consider stable size and excellent functional stability when designing connectors.

The performance of unmodified PA66 material can't meet some specific requirements. In this paper, some rules are found to guide the selection and design of connector products by comparing the performance changes of glass fiber before and after modification.

Effect of glass fiber reinforced PA66 on moisture absorption of connector

1.1 Glass Fiber Reinforced PA66

Any modification of nylon 66 that can improve the original performance of nylon 66 through mechanical, physical and chemical actions can be called modification of nylon 66. The application range of nylon 66 modification is also very wide. Almost all the properties of nylon 66 resin can be improved by modification methods, such as appearance, aging resistance, wear resistance, flame retardancy and cost.

Glass fiber reinforced modification is a common way to physically modify plastic materials. PA66 material reinforced by glass fiber not only improves the physical properties, but also improves the stability of products. However, the hygroscopicity of nylon material is an unavoidable problem in production. Moisture absorption will not only affect the size of nylon products, but also affect the mechanical properties, thus affecting the use function of the whole connector products. For the stability of products, it needs to be verified by experiments. At the same time, some rules can be found through the change of process data during the experiment, so as to know the connection design, product packaging, storage, transportation, etc. This experiment mainly compares 15%, 30% and 50% connector products with different glass fibers, and puts them in constant temperature and humidity. One group naturally puts the other group of samples into water, simulates the limit conditions, and monitors the two groups of samples according to the time change.

1.2 Experimental Methods

1.2.1 Experimental Materials

The experimental materials are provided by BASF (Shanghai) Trading Co., Ltd., and the brands used are A3WG3, A3WG6 and A3WG10.

1.2.2 Experimental Equipment

In this experiment, injection molding was used to manufacture a certain standard part in the connector market.

1.2.3 Experimental Operation

Three kinds of glass fiber reinforced products with 15%, 30% and 50% were made in the experiment. Each group of samples was divided into two parts, and one part was placed naturally in a constant temperature and humidity environment with a temperature of 22℃ and a humidity of 70%. The other part is immersed in pure water and placed in the same laboratory as the unwatered product for standing. After taking a sample of the products that are not immersed in water, take a sample of the products that are immersed in water, immersed in water and immersed in water for 7 days, 14 days, 30 days and 60 days, respectively, and measure the dimensional change and the change of terminal pulling force.

Terminal pull-out force is an important embodiment of connector performance, which directly reflects the realization of connector function and durability. In this experiment, the standard terminals produced by Tyco Electronics (Suzhou) Co., Ltd. are used. Because the product tolerance of the terminal industry is only 0.005mm, this experiment can default that there is no difference in the size and performance of the same batch of terminals, so the influence of terminal differences on this experiment will not be discussed here.

1.3 Experimental Results

By comparing the size results, it is found that the size in X direction is relatively stable compared with that in Y direction. The value of this immersion effect is the ratio between the dimensional change rates of the same group of products under the same time and immersion, and the overall change level in the X and Y directions is compared by this ratio.

The Y direction is perpendicular to the glue feeding direction, that is, perpendicular to the injection pressure direction. Compared with the X direction, the pressure received when the melt flows is relatively small, and the gap between PA66 melt and glass fiber is relatively large. By observing the size trend, it is found that the size of products increases slowly under natural conditions.

It can be seen that the terminal pull-out force of samples with different glass fiber contents under natural conditions is slowly decreasing. This trend decreases after the 7th day, and then starts to decrease after the 14th day's rebound. After the sample was soaked in water, it obviously decreased on the 7th day, and the terminal pull-out force of the soaked sample began to rebound on the 14th day, but the rebound amplitude was not significant. After the 14th day of immersion, the terminal pullout force began to stabilize, with a slight decrease, but not obvious. After 60 days, the terminal pullout force of the samples under the two conditions was close and showed a stable trend.

2 Full Text Summary

(1) The dimensional stability of PA66 material is poor, and its size changes greatly whether it is placed naturally or immersed in water, but it is more obvious after immersion, which accelerates its own water absorption process. The size change in the glue feeding direction is smaller than that in other directions, so we can refer to this feature in product design and design the key size in the glue feeding direction.

(2) The terminal retention force of 2)PA66 samples will decrease on the 7th day, whether it is placed naturally or immersed in water, but it is more obvious when immersed in water. On the 14th day, there will be a rebound, followed by a slow downward trend.

(3) This experiment shows that the terminal retention force of PA66 connector will be reduced by moisture absorption regardless of whether it is soaked in water or not, but the time is different. The greater the humidity, the faster the decrease. To change this situation, it is necessary to change the environment of the connector, such as sealed packaging, adding desiccant, etc. The addition of these measures can prolong the service life of PA66 connector.