Wet-Strength Resins for Paper Packaging

Simplified, cost-effective and scalable method to convert conventional hydrophilic paper into hydrophobic paper with improved water resistance and wet strength. The method involves immersing or spraying paper into a dilute solution of multivalent metal ions like Fe3+, Zr4+, etc, followed by drying. The metal ions coordinate with lignocellulosic fibers to induce hydrophobicity, water resistance and reduced water absorption. The metal-ion-modified hydrophobic paper retains high hydrophobicity, stability and wet strength after washing or storage.

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Water-resistant paper with improved printability, condensation resistance, and water resistance. The paper has a water-resistant layer on one side and an undercoat layer on the opposite side. The undercoat layer has specific smoothness and water absorbency. This allows the paper to have good print quality, prevent condensation, and still be water-resistant on the opposite side from the water contacting surface. The undercoat layer contains latex and pigment, and the water-resistant layer contains polyolefin or acrylic resins. The paper is suitable for packaging containers like cups that have both printed surfaces and contact with liquids.

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Filter material for tea bags and other food packaging that uses a biodegradable binder to enhance strength and compostability. The filter contains fibers and a non-fibrous binder like polylactic acid, polyglycolic acid, or copolymers thereof. This binder enhances wet strength properties like tensile and crimp strength compared to traditional synthetic binders. The biodegradable binder also prevents water ingress into the crimped area, making the fold more permanent and reducing dust transfer through the filter. The biobased binder improves compostability and sustainability compared to fossil-based binders.

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Pulp mold packaging made from cellulose fibers that is stronger, less prone to absorbing water, and has fewer air bubbles compared to conventional pulp mold packaging. The packaging is made by adding binders, defoamers, and water repellents to the cellulose pulp. The binders increase strength and elasticity, the defoamers remove air bubbles, and the water repellents prevent water absorption. The specific compositions of the additives are: binder with 79-81% water, pH 2.8-4.8, melting/freezing point 0°C, initial boiling point 90°C, boiling range 90-100°C, specific gravity 1.10-1.20; defoamer with 70-72% water, pH 5-

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Food packaging paper with improved crack prevention and oil and water resistance for preventing food spoilage when packaging foods like burgers and sandwiches. The paper has a primer layer on the substrate to prevent cracks, followed by a functional coating layer for oil and water resistance. The primer layer contains butyl acrylate, polybutylene adipate, butyl-2-propenoate, and polyethylene glycol. The functional layer has alcohol, fluorine compounds, paraffin wax, nitrocellulose, dicyclohexyl phthalate, and silicone resin. Coating the primer prevents cracks when folding the packaging. The functional coating provides oil and water resistance to prevent food absorption.

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A paper coating agent that provides oil and water resistance, as well as heat sealability, for paper. The coating agent contains a copolymer made from a carboxylic acid with a double bond and a (meth)acrylate, carnauba wax, and water. The copolymer has a glass transition temperature of 30°C or less. This coating agent can be applied to paper to impart oil and water resistance, and when heat sealed, forms a bonded layer. It allows replacing plastic coatings and sealing films on paper packaging, reducing plastic use and facilitating recycling.

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Decorative sheets, packaging boxes, and packages with improved moisture resistance for containing items like liquids. The sheets have a waterproof paper layer, a photocurable resin layer, and an adhesive layer. The waterproof paper provides moisture barrier and the photocurable resin layer adds water resistance. The adhesive layer bonds the layers together. This enables the sheets to maintain strength when contacting moisture. The sheets can be used in boxes and packages for items like liquids without delamination or peeling when exposed to moisture. The photocurable resin can be UV curable and contain acrylic monomers. The waterproof paper can have a resin component matching the photocurable resin.

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Packaging material made from unbleached kraft paper that doesn't tear when stretched and maintains elasticity over time. The paper contains at least 90% primary cellulose with a length-weighted mean fiber length between 2.0 and 2.9 mm and less than 5% fillers. It has a grammage between 65 and 170 g/m2. The kraft paper is coated with a polyolefin or PLA in small amounts to improve wet strength. The material can be formed into sleeves, bands, or loops by pivoting, folding, and closing the paper. The high strength-to-weight kraft paper replaces plastic packaging while avoiding the environmental issues of wet strength agents.

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Water-resistant paper with improved water resistance, blocking resistance, moldability, and heat-sealability compared to existing water-resistant papers. The paper has a water-resistant layer on one side of the paper substrate, with specific melting point ranges and resin composition. The water-resistant layer contains an ethylene-(meth)acrylic acid copolymer and a copolymer of ethylene and an unsaturated hydrocarbon other than ethylene. The ethylene copolymer/other copolymer mass ratio is 50/50 to 90/10. The copolymer with an unsaturated hydrocarbon other than ethylene likely contributes to the second melting point range of 100-120°C. The paper also has a pigment coating layer between the paper substrate and the water-res

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Biodegradable reinforced paper packaging material with increased strength and impermeability compared to conventional paper packaging. The material uses a biodegradable plant-based resin to chemically bond fibers within the paper layer and coat the surface with biodegradable low-density polyethylene. This reinforces the paper while maintaining minimal weight. The resin also improves wetting barrier properties. The reinforced paper packaging is biodegradable and reduces costs compared to using thicker paper or adhesives.

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An additive containing bacterial cellulose that can be used as a sustainable, biodegradable and renewable raw material source in the paper industry, especially in the production of packaging boxes. The additive improves air permeability, water absorbency and mechanical properties of the final product compared to using 100% recycled paper. It allows using 100% recycled paper as raw material in packaging boxes by adding 5-40% bacterial cellulose to compensate for the strength and performance issues of recycled paper.

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Paper packaging material for storing ice and frozen products that has waterproof properties to prevent melting water from seeping through. The packaging material is made by coating a waterproof resin layer onto at least one side of a paper substrate. The resin contains a synthetic resin like styrene or acrylic, and wax. The resin layer has low moisture permeability to prevent water leakage. The coated paper can be processed into bags for packaging ice and frozen products. The coating is heat-sealable and peels easily from frozen products.

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A water-soluble coating composition for paper and packaging materials that allows recycling and reduces waste. The coating composition contains a water-soluble acrylate-based polymer, PVA, and a PVA composite with a metal ion like calcium, magnesium, or zinc. The coating composition is prepared by mixing the acrylate polymer with calcium hydroxide generated by adding calcium oxide to water. The PVA is added last. This composition provides thermal adhesion, water resistance, and oil resistance. It enables reuse of paper packaging when discarded after use by avoiding contamination of the recycling stream. The coating composition can be applied to paper, nonwoven fabric, or fiber materials like masks, diapers, filters, or packaging.

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Aqueous dispersion and emulsion containing ethylene-vinyl alcohol copolymer and cellulose nanofibers for improved water resistance, strength, and barrier properties in films, coatings, papers, multilayer structures, and adhesives. The ethylene unit content of the ethylene-vinyl alcohol copolymer is 1-20 mol%. This range provides dispersibility, storage stability, and coatability while maintaining water resistance, tensile strength, and fracture properties compared to PVA-CNF dispersions.

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Paper wrapper for electrically heated aerosol-generating articles like vape devices that prevents tearing when removing the device from the vape. The wrapper has a wet tensile strength of at least 5 N/15 mm when wet, tested using a specific method. This high wet strength prevents tearing when the wrapped vape is heated and the moisture inside wets the paper. It allows easy removal without wrapper fragments getting into the vape device. The wrapper also optionally has a dry tensile strength of at least 10 N/15 mm.

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Aqueous dispersions and emulsions containing an ethylene-vinyl alcohol copolymer and cellulose nanofibers for making films with improved properties like water resistance, tensile strength, and reduced breakage compared to using just the copolymer. The ethylene unit content of the copolymer is 1-20 mol%. The nanofibers are dispersed in the aqueous medium containing the copolymer at 0.1-40 parts by mass. This composition improves film properties compared to just the copolymer alone. The dispersions and emulsions can be used to make films, coatings, papers, and packaging materials with enhanced properties.

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Preparation of a hyperbranched structure super absorbent functional material and its application in paper sizing material for packaging. The method involves mixing a Lewis base substance like glycerol or triethanolamine with an organic acid like terephthalic acid or citric acid in a temperature gradient reaction. The gradients are at room temperature, 40-100°C, and 100-160°C. This produces a super absorbent functional material with a hyperbranched structure. The material is used as a packaging paper sizing to improve wet strength.

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A packaging material with improved strength and waterproofing for export packaging applications. The material is made by coating the outer and inner surfaces of liner paper used in corrugated cardboard with specific compositions. The first coating contains epoxy, melamine, methanol, and water. The second coating contains a waterproofing agent (paraffin wax and polyolefin) and vinyl acetate emulsion. Applying and curing these coatings on the liner paper improves its strength and water resistance. The coated liner paper is then used to manufacture honeycomb boards with hexagonal cores. The honeycomb boards are heat-treated and laminated with polyethylene for the final packaging material.

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A process for producing paper and cardboard with improved moisture resistance for packaging beverage containers. The process involves adding specific polymers to the pulp during papermaking to enhance wet strength and tear resistance. The polymers include a cationic polymer, an anionic polymer, and a cationic starch. The addition order and reaction time between the polymers can be varied.

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A process for producing label paper and packaging board for beverage containers that has improved moisture resistance without using traditional moisture-resistant additives like epichlorohydrin or melamine. The process involves adding specific polymers and starch to the papermaking process to form a network mixture with the wood fiber pulp. The cationic polymer, anionic polymer, and cationic starch are added in specific amounts to the pulp feed. This network improves the paper's moisture resistance properties, like wet shear and wet breakage, without compromising printability or integrity.

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