Novel aluminum-free humidity-regulating lining paper for cigarettes and preparation method thereof

A preparation method of a novel aluminum-free humidity-regulating lining paper for cigarettes, wherein the novel aluminum-free humidity-regulating lining paper for cigarettes comprises a base paper layer, a dense barrier layer, a hydrophobic functional layer, and a composite humidity-regulating layer;

• the dense barrier layer and the hydrophobic functional layer are arranged in sequence on an outer surface of the base paper layer from bottom to top, and the composite humidity-regulating layer is arranged on an inner surface of the base paper layer;
• the dense barrier layer comprises polyvinyl alcohol (PVA) and glycerol, the hydrophobic functional layer comprises calcium stearate, a silane coupling agent, nanocellulose, and carboxymethyl cellulose (CMC), and the composite humidity-regulating layer comprises sodium alginate, nanoporous calcium silicate, glycerol, and hyaluronic acid;
• and
• the preparation method of the novel aluminum-free humidity-regulating lining paper for cigarettes comprises the following steps:
• S1, preparation of a dense barrier layer coating:
• preparing a PVA solution of a certain mass concentration, mixing the PVA solution and the glycerol at a mass percentage ratio of (70-95) %:
• (5-30) %, and adding water to adjust a viscosity of the dense barrier layer coating to 100 cp to 500 cp for later use;
• S2, preparation of a hydrophobic functional layer coating:
• preparing a CMC aqueous solution of a certain mass concentration, selecting a commercially available calcium stearate emulsion and a commercially available nanocellulose hydrogel, and preparing the hydrophobic functional layer coating according to the calcium stearate with a mass fraction of 2% to 15%, the silane coupling agent with a mass fraction of 0.5% to 2%, the nanocellulose with a mass fraction of 5% to 25%, and the CMC with a mass fraction of 60% to 90%, and adding water to adjust a viscosity of the hydrophobic functional layer coating to 200 cp to 800 cp for later use;
• S3, preparation of a composite humidity-regulating layer coating:
• preparing a sodium alginate aqueous solution of a certain mass concentration, mixing with a certain amount of the hyaluronic acid, adding the nanoporous calcium silicate and the glycerol in sequence, preparing the composite humidity-regulating layer coating according to the sodium alginate with a mass fraction of 50% to 80%, the nanoporous calcium silicate with a mass fraction of 10% to 30%, the glycerol with a mass fraction of 5% to 20%, and the hyaluronic acid with a mass fraction of 0.5% to 2%, and adding water to adjust a viscosity of the composite humidity-regulating layer coating to 300 cp to 900 cp for later use;
• S4, coating the dense barrier layer coating on one side of the base paper layer by any coating process selected from the group consisting of scraper blade coating, curtain coating, and scraper bar coating, and conducting non-contact hot air drying at 80° C. to 120° C. for 5 min to 20 min to obtain a coated paper with the dense barrier layer on the one side;
• S5, coating the hydrophobic functional layer coating on the one side with the dense barrier layer of the coated paper by the any coating process selected from the group consisting of the scraper blade coating, the curtain coating, and the scraper bar coating, and conducting non-contact hot air drying at 100° C. to 120° C. for 5 min to 20 min to obtain a coated paper with the dense barrier layer and the hydrophobic functional layer coated in sequence on the one side;
• and
• S6, coating the composite humidity-regulating layer on an uncoated side of the coated paper with the dense barrier layer and the hydrophobic functional layer in sequence by the any coating process selected from the group consisting of the scraper blade coating, the curtain coating, and the scraper bar coating, wherein if the dense barrier layer and the hydrophobic functional layer are coated on the outer surface of the base paper layer, the composite humidity-regulating layer is coated on the inner surface of the base paper layer, and conducting non-contact hot air drying at 100° C. to 120° C. for 10 min to 30 min to obtain the novel aluminum-free humidity-regulating lining paper for cigarettes.