外文翻译原文：胶印油墨的改性松香酚醛树脂的合成反应

Pigment if the viscosity and thickness are too low, the ink on the roller will be flying; if they are too high, they will cause the peeling of paper. Generally, it is expected that the thickness should be a little bit high, because high shear rate is necessary to disperse the pigment. Therefore, it is necessary for the ink resin to have both high soluble viscosity and high mineral oil tolerance. To achieve this, however, investigations on the rosin-modified phenolic resin with high solubility and high viscosity have been carried out. Conversely, introduction of petro resin and dicyclopentadialkene resin, or introduction of anhydride and ?, ?-unsaturated polyacid into the synthetic process to give further modification has been adopted too. All these modified resins can give out a satisfactory result in some single property, but cannot balance the gloss and solidification of the resultant ink; it means that, if the gloss is good, the cure will be slow, or it is reversed (Homma et al., 1987; Joseph et al., 1981). In this paper, we used the combination of alkyl phenol and vegetable oil to modify the resin in order to increase its molecule weight and to improve its mineral oil tolerance. By optimizing the raw materials and processes, a series of rosin-modified phenolic resins, used as ink vehicles, with high soluble viscosity and good mineral oil tolerance and good gelatinization was synthesized. Due to the reason that the oxidic polymerization of the oil portion would result in a cross-linking effect; even when the soft point of the resin was low, the solidification could still be fast, and the printing film had good wear- resistance. Furthermore, these resins had The authors Zhengqing Wang, Piying Gao and Pin Chen are based at East China University of Science the solution was titrated with 0.1mol/l standard KOH solution to the end-point, when the light-red colour can last for 30 secs. Acidity value can be calculated with formula: AV = 56.1 VN/W where: V = the volume (ml) of used KOH standard solution; N = the mole concentration of KOH standard solution(mol/l); W = weight of the resin (g); 56.1 = the millimole weight of KOH. Determination of the viscosity of resin (QB574-83) The viscosity means the solutions viscosity when the resin was dissolved in the linolic acid. Generally, the higher soluble-viscosity the resin has, the better the transfer printing, and the faster the volatilization of the solvent, and the bigger the cohesion the ink has, but the pigmentation will be a little bit lower. Determination method. Exactly 6g resin and 12g linolic acid were placed in a small crucible, heated on an electric heater(1kW), stirred until the temperature reached 2508C. After all the resin dissolved, the solution was cooled down to 258C; the viscosity was then measured with the spin-viscometer (Model NDJ-79). The viscometer was kept running for five minutes; when the reading was stable the meter was switched off (the reading would be zero); the meter was turned on again, and the sample reading as previously was just the viscosity of the resin. Determination of n-heptane number of resin The n-heptane number is also referred to as n- heptane tolerance, which is an index for judging the solubility of resin in petro solvents and the dispersibility of resin in the vehicle. If the resin oil (solution in linolic acid) can tolerate more solvent until the system becomes turbid, this indicates that the resin has better solubility in aliphatic hydrocarbon. Conversely, less solvent tolerance indicates that the rheological properties and water- resistant properties of the ink are affected. The n-heptane number was defined as the millilitre of n-heptane used by 2g resin oil; calculation is as follows: NT = 2 (V/m) Figure 1 Process 1 89 Synthetic reaction of rosin-modified phenolic resin Zhengqing Wang, Piying Gao and Pin Chen Pigment cooled down to 258C, the viscosity was measured, and taken as ?0. The above mixture was cooled from 2308C to 708C, 3g Al-iso-octylate was mixed with 12g mineral oil evenly in a 100ml beaker and the mixture was added into the flask, heated slowly to 1608C, isothermalized for 30 minutes and, cooled to 258C, the viscosity was measured, and taken as ?g. Determination of molecular weight and distribution with GPC Equipment: Waters 244 GPC-meter. Rinsing agent: tetrahydroforan (THF). Operating temperature: room temperature. Chromatogram column: Ultrastyr Agel 500. Gel size: 104A, 105A, 106A Results and discussion Rosin-modified phenolic resin is the most widely used resin for inks at present. Ascertaining how to increase the soluble- viscosity and mineral oil tolerance of the resin is the key to improving the ink quality, also a difficulty to be overcome in the production of the resin (Matsumoto et al., 1989). Effect of amount of resol on the resin properties The amount of resol used had a big influence on the viscosity of the synthetic resin. Table I shows that, when the resol accounted for about 50 percent to 60 percent against the total rosin, the soluble viscosity of the resin could increase from 12.2 N-s-m2to 30.5 N-s-m2. The reason for this was that the resol could inner-molecularly dehydrate under high temperature to form methylene quinone (see Formula 1, Figure 2) which reacted with the conjugated double bond in the rosin acid molecule by Diels-Alder adduction(see Formula 2, Figure 2). The adduction could probably take place in the form levopimaric acid instead of rosin acid, because it was difficult for the conjugated double bond to carry out the adduction between two rings. When the reaction temperature increased, the rosin acid could isomerize into levopimaric acid, which then undertook the adduction(see Formula 2, Figure 2). Some researchers assumed that the rosin acid could also react with the hydroxyl methyl condensate (resol) to form condensate product (Formula 3, Figure 2) and esterification product (Formula 4, Figure 2), thus, in turn, contributing to the increase of the resin molecular weight. Obviously, with the increase of the resol amount added, the number of reactive hydroxyl methyl condensate would increase. The result was favourable to forming a large quantity of complex macromolecular ring structures, which, in turn, increased the solubility and gelatinization of the resin. Effect of method of feeding resol on the molecular weight of the resin The speed of feeding resol affected the molecular weight of the synthetic resin greatly. Gradual, even dropping of resol would produce a much greater molecular weight and higher soluble viscosity synthetic resin than feeding resol all at once (see Table II). According to the analysis of the mechanism of the reaction between resol and rosin acid Table I Effect of amount of resol on the resin properties SampleResol (%)?258C/(N-s-m2)NTGTAverage 0504-A50.012.24.13.416.3 0504-B54.516.53.45.024.8 0504-C56.822.03.1Gelling17.4 0504-D60.030.52.5Gelling24.2 90 Synthetic reaction of rosin-modified phenolic resin Zhengqing Wang, Piying Gao and Pin Chen Pigment 1203-A sample was feeding at once, while 1203-B was dropping by 3h. The difference was obvious as shown in Table II. The Mw of 1203-B was much greater, and the soluble viscosity was much higher. Furthermore, by adopting the dropping method, the dehydration could take place in a stable fashion, avoiding the rimming action during the synthetic reaction, thus giving better control of the operation. Effect of the alkyl group of the phenol on the properties of resin In order to improve the solubility of rosin- modified phenolic resin against petroleum solvent, it was favourable to chose bigger alkyl group phenol. In this paper, we used the mixture of butyl phenol resol and octyl phenol resol to evaluate the effect of alkyl group on the resin viscosity and heptane number. The results listed in Table III are shown in Figures 3 and 4. The results indicated that with the increase of octyl phenol resol in the system the mineral oil tolerance of the resin was increased but the viscosity decreased. This was because the long carbon chain of octyl group has better oil compatibility, but conversely, it has greater Table II Effect of method of feeding resol on the resin properties and molecular weight Sample Method of feeding resol?258C/(N-s-M2)NTMn? 10?1Mw? 10?1 1203-AFeeding at once4.85.10.163.4 1203-BDropping by 3h14.64.80.1715.93 Figure 2 Formulae 1-4 Table III Properties of alkyl phenol resols modified resin Butyl phenol resol/(% w) Octyl phenol resol/(% w)?258C/(N-s-m2)NT 7525.017.54.0 6040.016.06.3 1882.04.513.0 Figure 3 Formula 5 Figure 4 91 Synthetic reaction of rosin-modified phenolic resin Zhengqing Wang, Piying Gao and Pin Chen Pigment the hydroxyl groups it possesses could dehydrate under high temperature to form conjugated double bonds which would take part in the reaction. Results from experiments indicated that the introduction of both tung oil and castor oil into the synthetic process could result in better modification. The resin molecular weight and oil solubility could be increased simultaneously. References Homma, M.et al.(1987), Phenolic-modified rosin esters, USP, Vol. 4 No. 639, p. 492. Joseph, M.M.et al.(1981