| Using waste paper to make pulp and paper has been aroused the widespread attention around the world, because it has many advantages in low relative cost, saving raw fiber resources, simplifying the process of papermaking, reducing environmental pollution and contribute to environmental protection, Waste paper deinking is the key link of pulping and papermaking with waste paper, meanwhile, the deinking agent is the most important chemical assistant in the process. At present, there are few varieties of domestic deinking agents. Most deinking agents are the mixtures of commercially available small molecule surfactants. The performance of domestic deinking agent is relatively poor, so it can not meet the requirements of the production of high-grade recycled paper. Therefore, to research and development the efficient new type deinking agent is one of the key work to improve the level of waste paper deinking. In this paper, the two novel type LIP and AI-T-IA surfactants with high molecular weight were synthesized by nucleophilic addition method. Isophorone diisocyanate (IPDI) is the main raw material. The reaction conditions and the performance of deinking agent were studied. The main contents and results of the study are summarized as follows:(1) A series of LIP nonionic surfactants were synthesized by using of lauroyl diethanolamide(LDEA), isophorone diisocyanate(IPDI) and different molecular weight polyethylene glycol(PEG) as raw materials. Compared with the deinking effect of the prepared products by the flotation deinking with waste journal paper, and evalued the effect by whiteness and the residual ink concentration, the optimum proportion and reaction conditions were investigated. Afterwards, the comparison of deinking efficiency between the self-prepared and the mixed deinking agents was carried out. The surface residual ink and degree of crosslinking of regenerated fiber were characterized by scanning electron microscope(SEM). Then, The chemical structure of the products were characterized by FT-IR and 1H-NMR, and the surface physical properties were determined.The results showed that when n(LDEA): n(IPDI):n(PEG)(the molar ratio of LDEA/IPDI/PEG) was 1.0:2.0:2.0, the reaction was carried out at 55℃ for 2 h with 1.0% catalyst, and the relative molecular weight of PEG is 600, the product LIP-600 had the best deinking effect. the whiteness of the deinked pulp could reached 71.2%ISO and the residual ink concentration was 52.5 mm2·m-2, and its deinking effect was much better than the commercially available deinking agents. Compared used LIP-600 alone, the mixture of LIP-600、AEO-9 and AES (m(LIP-600):m(AEO-9):m(AES)=2:1:1) had better performance. The whiteness of the deinked pulp increased by 1.1% ISO and the residual ink concentration decreased by 1.1 mm2·m-2. The SEM photos showed that the surface of fiber was smoother and the effective residual ink concentration was lower. Physical performance test results showed that the surface tension of synthetic product was 34.48 mN·m-1, the CMC value was 1.36×10-5 mol·L-1, the cloud point was 53℃, the HLB value was 13.33, the bubbly proportion was 80.5%, and separation water time method measured emulsifying power was 589 s.(2) AI-T-IA surfactant was synthesized by lauryl alcohol polyoxyethylene (9) ether (AEO-9), isophorone diisocyanate (IPDI) and tartaric acid. Compared with the deinking effect of the prepared products by the flotation deinking with waste journal paper, and evalued the effect by whiteness and the residual ink concentration, meantime, the optimum proportion and reaction conditions were investigated. Afterwards, the comparison of deinking efficiency between the self-prepared and the mixed deinking agents was carried out. The surface residual ink and degree of crosslinking of regenerated fiber were characterized by scanning electron microscope(SEM). Then, The chemical structure of the products were characterized by FT-IR and 1H-NMR, and the surface physical properties were determined.The results showed that when the molar ratio of AEO-9 to IPDI to TA was 2.0:2.2:1.0 and the reaction was carried out at 105℃ for 3.5 h with 1.0% catalyst, the synthetic product had the best deinking effect, the whiteness of the deinked pulp could be reached to 69.5%ISO and the residual ink concentration was 57.8 mm2·m-2, its deinking effect was better than the commercially available. When m(AI-T-IA):m(AEO-9):m(AES)=1:2:1 and dosage of its was 0.2% of the dry paper, the whiteness of the deinked pulp could be increased by 1.3%ISO and the effective residual ink concentration could be decreased by 3.3 mm2·m-2 compared it was used alone. The SEM showed that the surface of fiber was smoother and the effective residual ink concentration was lower.Physical performance test results showed that the surface tension of synthetic product was 35.96 mN·m-1, the CMC value was 0.52 mmol·L-1, the acid value was 43.81 mgKOH·g-1, the bubbly proportion was 69.80%, and separation water time method measured emulsifying power was 416 s.(3)the experiment was based on the LIP-600 as deinking agent, and evalued the effect by whiteness and the residual ink concentration, reseached the influence of deinking process in the flotation deinking to the waste journal paper, then the deinking effect of flotation method and washing method on the waste book paper was comparedThe results showed that the pulping time was 30 min at 50℃, the curing time was 30 min at 55℃, the floation time was 8 min at 45℃, the surfactant dosage of LP-600 was 0.3%, Na2Si03 was 3%, NaOH was 1%, First adding the agent, after adding waste paper feeding sequence.Under this condition, the waste journal paper was deinked by flotation method and the LIP-600 as deinking agent, the whiteness of the deinked pulp could be reached to 73.2%ISO and the residual ink concentration was 46.6 mm·2m-2,which improved 2.0%ISO and decreased 6.1 mm·2m-2 than unoptimized. meanwhile the waste book paper should be deinked with washing method, when the amount of LIP-600 is 0.3%, the whiteness of the deinked pulp can be reached to 64.1%ISO. |
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