The demand for paper continues to grow worldwide. Paper is not only a necessity for daily life, but also an important material for writing and printing. Currently, paper is also being used as a more environmentally friendly packaging alternative in retail and e-commerce, and may also has some innovative applications such as cardboard furniture and accessories. To serve this diversified market, paper manufacturers are constantly looking to improve their productivity through better processing. The organosilicon materials based on polysiloxane (silicone) as a new type of material have special physical and chemical properties, which are widely used in the paper industry. They contribute in many aspects to improve the pulping process, which in turn increases paper productivity.
At present, the application of silicone in paper industry is mainly reflected in paper defoaming, paper softening, paper anti-sticking, paper reinforcement and etc.
Used as defoaming agents: In pulp and paper industry, foam treatment is always a thorny problem. From the pulping process to the coating process, foams are existence with different degrees, which seriously affect the normal production of paper and paper quality. Silicone defoaming agents have been universally praised in the paper industry because of their strong versatility, high defoaming efficiency, good compatibility and large market potential. At present, silicone defoaming agents can be mainly divided into four types of silicone oil type, silicone oil solution type, silicone oil mixture type and silicone oil emulsion type according to their physical properties, and the silicone oil emulsion is the most used one.
Used as paper softener: The softness of paper is a very important quality index of tissues, toilet paper, napkins and other household paper. Chemicals are often used to improve the softness of the paper. And silicone paper softener has shown outstanding performance that can give the paper a good softness, flexibility and smoothness. Its action mechanism is that the polar silicon oxygen chains of softener can form hydrogen bonds with the paper fibers, and the hydrophobic groups of softener are arranged outward to form a non-polar isolation membrane, which greatly reduces the intermolecular forces between paper fibers, thus decreasing the rigidity and stiffness of paper. Silicone paper softener mainly includes the following four categories: polysiloxane surfactant, quaternary ammonium salt modified organic silicone oil emulsion, amino silicone oil and its emulsion, and cationic hydroxyl silicone oil emulsion.
Used as paper reinforcing agent: Paper relics are important historical and cultural heritages. However, the paper relics are at risk of ageing, damage and disappearance. In order to delay the aging of paper, improve the strength of paper, solve the problem of poor permeability and stability of traditional resins to paper, Jin et al. synthesized the modified polyurethane by using polydimethylsiloxane (HTPDMS) and low molecular weight hexamethylene diisocyanate (HDI) trimer . Results showed the paper coated by HTPDM-modified polyurethane liquid had good mechanical property and the materials had great application prospects in the protection of paper.
Fig. 1. The synthetic route for obtaining HTPDMS-modifed polyurethane.
Others: Silicone can be also used as an anti-sticking agent for papermaking, effectively preventing the penetration of adhesive molecules into the paper. In addition, it has been reported that the chemical modification of polyacrylamide with silicone can obtain a kind of papermaking additive with enhanced properties, which can be used as paper enhancer.
What can we do?
Alfa Chemistry has many years of research strength in the field of organosilicon applications and is committed to promoting the further application of organosilicon in the field of pulp and paper industry. We can provide customers with a variety of organosilicon materials and related technical support and services for papermaking. Today, we have served many companies in the pulp and paper industry, and our high-quality products and technical services bring great benefits to them. If you require any assistance, please contact us and our team will provide you with fullest support at the most abundant experience and the most affordable price.
- Jin S. S., et al. The application of organosilicon modified polyurethane in reinforcing traditional paper[J]. Nordic Pulp & Paper Research Journal, 2019, 34(4): 485-494.