Abstract: This work was conducted to test the shear strength and peel strength of surface-treated PTFE membranes and copper alloy specimens bonded with epoxy adhesives, and to examine the water aging resistance, salt spray-resistant aging resistance and resistance of epoxy adhesives. Mold aging properties.
1 Introduction
For materials used in electronic equipment and equipment that often work in humid environments, it is often necessary to examine the aging properties of the selected materials for water resistance and environmental resistance in order to maintain their normal operation for a long period of time. So far, there have been some reports on the aging properties of epoxy adhesives [1-6]. This article mainly investigates the performance of epoxy adhesive adhesives developed for water aging, salt spray resistance, and mold resistance.
2 Experimental Results and Discussion
2.1 epoxy adhesive
3# is epoxy adhesive without any filler in the formula. 2# is a hydrophobic fumed silica added to the adhesive formulation, but its addition amount is less. 4# is added with talcum powder and titanium dioxide in the adhesive formulation. 1# is a homemade modifier A added to the adhesive formulation.
2.2 Aging test results
Waterproof aging of adhesives: The aluminum alloy adhesives were placed in tap water at a constant temperature of 98±1°C, and the strength of the adhesives before and after aging was measured after boiling for a certain period of time. Figure 1 shows the results of an adhesive boiled test. As can be seen from Figure 1, for the 3# sample, the intensity first rose in the boiling process. When the boiling time was greater than 9 hours, the intensity decreased with the prolonged boiling time, but After boiling for hours, the intensity reduction rate was 4.4%. For the 2# sample, during the boiled process, the intensity showed a declining trend with the prolonged boiled time. After 72 hours boiled, the intensity reduction rate was 37.1%, indicating a large decrease, indicating that the hydrophobic gas phase II Silicon oxide not only does not increase the water resistance of the adhesive, but also makes the adhesive more vulnerable to the effects of water and causes a greater loss of strength. For sample No. 4 in the boiling process, the strength first showed a rising trend. After being boiled for 72 hours, the strength increased by 1.01% compared to the initial strength. The results in the figure show that the formula adhesive has good water resistance. For the 1# sample, the shear strength of the adhesive was significantly increased during the initial stage of boiling, and when the boiling time was greater than 9 hours, the strength decreased with the prolonged boiling time, but after 72 hours of boiling, the strength The rate of increase from the initial strength was 49.4%. The results in the figure show that Modifier A greatly improves the water resistance of the adhesive.
Bonded salt water, salt spray, and mold-resistant aging:
Application of FRP Honeycomb Sandwich Composite Material in Anti-explosive Structure Design
The bonding material is a copper alloy/PTFE film/copper alloy in which the surfaces of the PTFE film are first treated with a sodium-naphthalene method, and the surface of the copper alloy bonding portion is first subjected to oxidation treatment.
Brine tolerant: The adhesive is placed in a 5% aqueous solution of sodium chloride. After the brine is heated and boiled in a pressure cooker for a certain period of time, the strength of the adhesive before and after aging is measured. The test results are shown in Table 1. It can be seen from Table 1 that, after being continuously aged under severe conditions for up to 42 hours, the adhesive member has a shear strength retention rate of 58.1% and a peel strength retention rate of 72.3%.
Resistance to salt spray aging: test concentration of sodium chloride solution: 5±1%; PH=6.5-7.2, test temperature: 35±2°C, test time: 21 days. The salt spray resistance test results of the epoxy adhesive adhesives are shown in Table 2. From Table 2, it can be seen that after 21 consecutive days of salt fog aging, the shear strength of the adhesives decreases by 15.3%. The decrease in peel strength was 2.62%, and the decrease in strength was small.
Anti-fungal aging: The test strains were Aspergillus niger, Aspergillus flavus, Aspergillus versicolor, Penicillium funiculosum, Chaetomium globosum. The test was conducted under alternating temperature and humidity conditions. Cycling is repeated every 24 hours. The temperature is maintained at 30±1° C. for the first 20 hours and the relative humidity is 95±5%. In the following 4 hours, the temperature is 25±1° C. and the relative humidity is >95% for at least 2 hours. The test time is 28 days.
The test results of the mold-resistance aging resistance are shown in Table 3. As can be seen from Table 3, after 28 days of continuous mold aging, the bond strength decreased by 8.70% and the peel strength decreased by 19.7. %, the decrease in intensity is not significant.
3 Conclusion
It can be seen from the above studies that the developed epoxy adhesives, especially those containing the modifier A, have better water and salt water aging properties; under salt fog aging conditions, the impact on peel strength The effect on shear strength is less; but under the condition of mold aging, the effect on the peel strength is greater than the shear strength. In short, the developed epoxy adhesive is better in terms of water resistance, salt spray resistance, and mold resistance.
(Author/Jiang Xingsheng Guo Jinyan Sun Mingming Zhang Junying Pei Mingming Wang Bo
Heilongjiang Institute of Petroleum Chemistry
Shengruisi Packaging Co., Ltd. , http://www.symakeuppackaging.com