The phenolic resin laminated substrate is subjected to vacuum thermal cracking using a temperature-programmed pyrolysis furnace reactor, and the raw materials and products are analyzed by elemental analysis, Fourier transform infrared (FT-IR) analysis and gas chromatography-mass spectrometry (GC-MS). The oil components were characterized. Studies have shown that pyrolysis oil supernatants are mainly soluble in water, such as phenol, cresol, xylenol, sugars, hydantoins, morpholines, pyrones and pyridines. Compounds and the like; while the lower layer precipitates are mainly insoluble or poorly soluble in water, such as large substituted phenols (substituent carbon number ≥ 2), triaryl phosphates, fatty acid esters and nitrile compounds. Among them, melamine has a higher content in the supernatant and the lower layer. With Bluetooth Retractable Ceiling Fan Hidden Blade Ceiling Fan,Fandelier Retractable Blades,Ceiling Light With Retractable Fan,Crystal Retractable Ceiling Fan JIANGMEN ESCLIGHTING TECHNOLOGY LIMITED , https://www.windfansummer.com
1 Introduction
With the acceleration of the frequency of electronic product replacement, the number of discarded electronic appliances has increased rapidly. The board is part of the waste appliance. At present, there are many methods for processing used circuit boards. Among them, pyrolysis technology has the advantages of easy separation of metals, glass fibers and organic materials, and is environmentally friendly, so the technology has a very good application prospect. At present, the research on the disposal of waste circuit boards by pyrolysis technology is mainly focused on epoxy resin circuit boards, and the pyrolysis treatment of phenolic resin circuit boards is rarely reported. In this study, vacuum flame cracking technology was used to study the flame retardant FR-1 phenolic laminate substrate. Since the manufacturing process of the FR-1 laminated substrate is mainly based on the tung oil-modified phenolic resin as a main resin, a part of the epoxy resin and the nitrogen-containing resin (such as melamine formaldehyde resin, aniline formaldehyde resin, hydantoin resin, etc.) are added, and Flame retardants, curing agents, plasticizers and other additives are used together. Therefore, the thermal cracking reaction process of the laminated substrate is complicated, and the obtained oil product has many components, and the boiling point and molecular weight thereof are also relatively close. It is difficult to analyze by conventional instruments, and GC-MS can be used for qualitative and convenient determination. And quantitative analysis, supplemented by Fourier transform infrared (FT-IR) analysis and elemental analysis can better determine the product oil composition, which provides a theoretical basis for the subsequent treatment and application of pyrolysis oil.
2 experimental part
2.1 Instruments and materials
NicoletMagnaaVaTR-360 Fourier transform infrared spectrometer (Nicolet, USA); 2010 gas chromatography-QP2010 mass spectrometer (Shimadzu Corporation, Japan); VarioELIIICHNS elemental analyzer (Elementar, Germany); DWJ-3L cryotrap (Beijing Songyuan Huaxing) Technology Development Co., Ltd.); WTS type temperature control device (Southeast University Automation Instrument Research Institute); DP-a digital pressure gauge (Nanjing Sangli Electronic Equipment Factory); TW-1a rotary vane vacuum pump (Wenling City Tingwei vacuum) Equipment Co., Ltd.); homemade heating resistor furnace. Methanol (chromatographically pure, Tianjin Damao Chemical Reagent Factory). The material used in the experiment is flame retardant FR-1 paper-based phenolic laminated copper clad plate (Changsha Weisi Electronic Circuit Co., Ltd.). This experiment does not consider the role of metal elements, so the circuit board used is light plate and copper on the plate. The foil has been etched away.
2.2 Experimental procedures and methods
2.2.1 Experimental procedure The circuit board was cut into pieces of about 1 cm × 1 cm, and 20 g was weighed and placed in a homemade thermal cracking reactor. The experimental process is shown in Figure 1. Under vacuum conditions, progress to the final pyrolysis temperature at a set temperature increase rate for a certain period of time. The gas and aerosol generated by the cracking reaction are quickly pumped away from the reactor into the cryotrap (secondary, minimum temperature up to -40 ° C), condensed to obtain pyrolysis oil; the uncondensed part is passed through the absorption tower (soda lime Absorbent) In addition to the aerosol and acid gas, the remaining gas is pumped out by a vacuum pump and fed into a gas absorption tank (30% NaOH solution), and the purified gas is directly emptied. The pyrolysis oil was subjected to FT-IR and GC-MS analysis.