C5 hydrogenated petroleum resin is a high-quality petroleum resin product derived from the continuous development of petroleum resin to light color, specialization and multi-purpose in recent years. It is a by-product C5 fraction of ethylene cracking as the main raw material. Low molecular weight thermoplastic resin is produced by pretreatment, thermal polymerization, polymerization, resin hydrogenation, stripping and other processes. C5 hydrogenated petroleum resin not only has the characteristics of high peel strength, good fast tack, stable bonding performance, good compatibility, etc., but also has the characteristics of colorless, odorless, heat resistance, weather resistance, low volatile matter, etc., can be used for Bonding hot melt adhesives for the packaging of high value-added products such as hygiene products, food and medicine.
Why is the viscosity measurement of C5 petroleum resin necessary?
Viscosity is an important index to evaluate the performance of C5 hydrogenated petroleum resin. In the production process of C5 hydrogenated petroleum resin, the change of viscosity will affect the color and softening point of C5 hydrogenated petroleum resin. If the viscosity is too high, the molecular weight of the petroleum resin will increase, and the structure will tend to be complex, which is not conducive to the normal progress of the hydrogenation reaction of the resin. At the same time, the consumption of hydrogen will increase, and the yellow index of the resin will increase; if the viscosity is too low, the molecular weight of the petroleum resin will be increased. The distribution is wider and the content of oligomer increases, which is not conducive to the adjustment of the softening point of the resin in the stripping process, and increases the energy consumption at the same time. Measurement and control of the viscosity of crude resin liquid, the amount of catalyst added in the polymerization reaction, the control of reaction temperature, the amount of circulating materials and the control of residence time, the control of chromaticity in the process of resin hydrogenation and the regulation of softening point in the stripping process Equals are very important.
The melt viscosity of C5 hydrogenated petroleum resin products will affect the performance of hot melt adhesives, pressure-sensitive adhesives and other products. If the melt viscosity is too high, the wettability of hot melt adhesives and pressure-sensitive adhesives will decrease, which is not conducive to hot melt adhesives. Adhesive bonding and pressure-sensitive adhesive coating; if the melt viscosity is too low, on the one hand, it may cause the filler in the hot melt adhesive system to settle and cause uneven distribution of material components; a decrease is not conducive to bonding
Measurement method of C5 petroleum resin
Use DV2T standard viscometer + Thermosel heater to measure the melt viscosity of a crude resin liquid of C5 hydrogenated petroleum resin (sample 1#, test temperature 150 ℃) and finished product (sample 2#, test temperature 190 ℃). Thermoset heaters are designed for high-temperature viscosity measurements and provide test temperatures up to 300°C. Rheocalc T software is used to edit test programs, and acquire and analyze test data.
DV2T Viscometer + Thermosel Heater
The influence of changes in test conditions such as constant temperature time, rotor speed, test temperature and sample addition amount on the results of rotational viscosity test during the viscosity test of C5 hydrogenated petroleum resin products. Through the analysis and regulation of these influencing factors, a suitable viscosity test method is established to further improve the accuracy and precision of the viscosity test method for C5 hydrogenated petroleum resin products.
Add a certain amount of sample to the sample cup, slowly immerse the rotor into the sample, and then keep the temperature constant in the heater for a certain period of time, and set the corresponding test method in the Rheocalc T software to conduct the viscosity test.
It can be seen from the above test results that when the constant temperature time is less than 15 minutes, the viscosity of samples 1# and 2# is high, and the readings are unstable; when the constant temperature time is 15-30 minutes, the viscosity values of the two samples are stable, which is Constant temperature time; but when the constant temperature time reaches 60 min, the viscosity shows an upward trend. The possible reason is: the volatilization of some components in the resin under high-temperature conditions, which leads to the increase of resin concentration and viscosity.
Under the same conditions of constant temperature time and test temperature, set different rotor speeds to keep the torque reading of the viscometer between 10% and 90% as much as possible, and investigate the effect of rotor speed on the viscosity of C5 hydrogenated petroleum resin. According to Table 2 above, the viscosity and torque readings for both samples changed when the rotational speed was changed. When determining the viscosity test method, it is better to control the torque reading range in the medium to high torque range. Both samples 1# and 2# can choose the speed range of 6-10 RPM for viscosity testing.
According to the operating manual of the viscometer, the recommended sample volume for the SSA special rotor used in this article is 8mL. Under the same other test conditions, according to the sample addition amount in Table 3, the influence of different sample amounts on the viscosity of C5-hydrogenated petroleum resin was investigated. According to the test results, it can be seen that the slight change of the sample addition amount has an impact on the viscosity test results, and the viscosity value increases with the increase of the sample addition amount. Therefore, it is recommended that when weighing resin samples, a slight deviation can be allowed near the required sample size of the selected rotor, but the weighing deviation should not be too large, and try not to exceed ±0.2 mL.
Viscosity is closely related to temperature, and a slight deviation of the test temperature has a great influence on the viscosity value. In this paper, for samples 1# and 2# under certain other conditions, the influence of temperature on the viscosity within the range of ±1°C of the set temperature is investigated. The viscosity test setting temperature of samples 1# and 2# is 150°C and 190°C, respectively.
It can be seen that within the range of ±1°C of the set temperature, the test results are significantly affected by the temperature. The higher the temperature, the lower the viscosity. Therefore, during the viscosity test of C5 hydrogenated petroleum resin, great attention must be paid to the control of temperature accuracy and stability. An insulating cap should be placed on the sample cup.