Synthesis Of Water-bone Environmentally Benign Wet-Strength Agents And Its Application On Paper Making

The synthesis of two kind of water-bone environmentally wet strength agent of paper and their applications on paper making were investigated in this paper. Firstly, the synthesis of starch-TDI polymer in which the starch was used as the soft part of the polyurethane was investigated. In the process of synthesis of polyurethane prepolymers, it was found that the end-point selection of synthesis affected the synthesized products. In addition, the change of NCO groups, reaction time and the content of blocked polyurethane were measured. In the process of synthesis, the temperature should be control between 60℃to 70℃, The best time of prepolymerization was 2 hours. In the blocking process, the temperature should be control below 5℃and the time of the blocking was 25 minutes. The complex was confirmed by FTIR spectra. It was found that the–OH on the fiber has connected with the–NCO on the TDI. We discussed its application in paper coating and found the physical properties of modified paper such as the break length, wet strength, tear index and burst index were all enhanced,especially the wet strength, was 5.19 times to the unmodified. The ratio of wet-strength to dry-strength reached 18.0%. Effects of the starch-TDI polymer used in wet-end adding included the pH, the dosage of starch-TDI polymer, and the sequence of adding the Al3(SO4)2 and so on. When the pH was 5～6, the dosage of starch-TDI polymer was 0.3%～0.4%, adding the Al3(SO4)2 after adding the starch-TDI polymer, the physical properties of modified paper were significantly enhanced. The ratio of wet-strength to dry-strength reached 17.2%.It was discussed that the synthesis of water-bone Epoxy acrylic (EA) UV-curing resin and its application in pulp and paper making. By the experiment it was found that the best way to synthesize the water-bone EA UV-curing resin was as follows: the temperature of the synthesis of the EA resin was 95℃; the reflection time was about 4 hours; the anti-agglomeration agent was 4-Methoxyphenol and the dosage was 0.25%; the catalyzer was N,N-dimethylaniline and the dosage was 1.0%; The ratio of the acrylic acid equivalent to epoxide equivalent was 1.00:1.00; the temperature of maleic anhydride modified the EA resin was about 80℃; the reflection was about 1 hour; the catalyzer was tetramethylammonium bromide and the dosage was 1.0%; the ratio of maleic anhydride equivalent to hydroxide equivalent was 1.00:1.00; The antacid agent was triethanolamine; the pH was 6～7.It was found that the physical properties of coating paper were enhanced significantly when photosensitive resin was used as a component of coating color. When the ratio of the resin was 40%, the coating using dosage was around 15 g/m2, the strength of the coating paper was the best. The ratio of the wet-strength to the dry-strength was 19.6%. Therefore, the photosensitive resin could be used as paper wet-strength agent. Effects of photosensitive resin used in wet-end adding included the dosage of the photosensitive resin, pH and the dosage of the Al3(SO4)2 and so on . By the Scanning electricity mirror and the FTIR of the coating paper which was degraded by the cellulase, it was found that the photosensitive resin had inter-penetrated with the fiber, restricting fiber swelling and hydrolyzing. By the way, the physical strength of the paper had enhanced, specially the wet-strength.We also used the PEG-400 to modify the water-bone Epoxy acrylic (EA) UV-curing resin in order to reduce its viscidity. It was found that when the modified resin used both in paper coating and wet-end adding, the result of the strength of the modified paper was better than that of non-modified. When the ratio of the resin was 40%, the coating using dosage was around 15 g/m2, the ratio of the wet-strength to the dry-strength of the coating paper was 19.8%. The reason was that as the viscidity was lower, the penetrability of the resin on the paper was better. After modified, the molecule was longer, and it could connect more fibers together. But because the double chemical bond was less in the modified resin, so it need longer time to curing.