CN-121471801-B - Low-water vapor transmittance coating for packaging material and preparation method thereof

Abstract

The invention relates to the technical field of packaging materials, in particular to a low-water vapor transmittance coating for a packaging material and a preparation method thereof. The low-water vapor permeability coating for the packaging material comprises, by mass, 25-40% of modified polyurethane resin, 5-20% of a linear paraffin compound, 3-15% of a hydrophobically modified acrylic resin, 1-5% of amino-terminated polyamide amine, 1-5% of silica particles, 3-5% of hydroxyethyl cellulose, 0.1-0.5% of an amino curing agent, 1-3% of a water-based auxiliary agent and the balance of water. The coating formed by the coating has ultralow water vapor transmittance, has a heat sealing function, is simpler and more convenient in processing technology without additional technological treatment such as glue, film coating or film covering, and the like, has a transparent coating with a surface dyne value of more than 42, and does not influence the paper appearance, subsequent printing and other technologies.

Inventors

• HUANG CHUANJUN
• YANG CHUN
• YAO LIANG
• WANG LEI
• YANG QING

Assignees

• 上海顺灏新材料科技股份有限公司

Dates

Publication Date

20260505

Application Date

20260108

Claims (6)

1. 1. The low-water vapor permeability coating for the packaging material is characterized by comprising, by mass, 25-35% of modified polyurethane resin, 5-20% of a linear paraffin compound, 3-15% of a hydrophobic modified acrylic resin, 1-5% of amino-terminated polyamide amine, 1-5% of silica particles, 4% of hydroxyethyl cellulose, 0.3% of an amino curing agent, 2% of a water-based auxiliary agent and the balance of water; The linear paraffin compounds comprise oxidized polyethylene linear paraffin compounds or/and aqueous polypropylene linear paraffin compounds; the silica particles are prepared by adding nano silica, methyltriethoxysilane and saturated ammonia water into absolute ethyl alcohol, stirring for 5-15h, filtering, washing and vacuum drying; The hydrophobic modified acrylic resin is prepared by adding methyl methacrylate, butyl acrylate, methacrylic acid, acrylic ester end-capped siloxane and vinyl triethoxysilane into water, stirring for 10-30min, adding emulsifier, stirring for 1-2h, adding initiator, and stirring for 2-6h at 70-80 ℃.
2. 2. The low water vapor transmission coating for packaging material according to claim 1, wherein the aqueous auxiliary agent is ethanol.
3. 3. The low moisture vapor transmission coating for packaging materials according to claim 1, wherein the modified polyurethane resin is a silicone modified polyurethane.
4. 4. The low water vapor transmission coating for packaging materials according to claim 1, wherein the mass ratio of methyl methacrylate, butyl acrylate, methacrylic acid, acrylate-terminated siloxane, vinyltriethoxysilane, emulsifier, and initiator is 5-15:1-5:1-2:1-2:0.1-1:1-2:0.1-1.
5. 5. A process for producing a low water vapor transmission coating material for packaging material as claimed in any one of claims 1 to 4, comprising the steps of, (1) Adding hydroxyethyl cellulose into water, and stirring to obtain mother liquor A; (2) Adding the modified polyurethane resin into the mother solution A, and stirring to obtain a mother solution B; (3) Adding amino-terminated polyamidoamine into the hydrophobically modified acrylic resin, stirring for 2h, adding silicon dioxide particles and water, mixing and grinding for 2h to obtain master batch C; (4) Adding the linear paraffin compound, the aqueous auxiliary agent and the amino curing agent into the mother liquor B in sequence, stirring, adding the mother liquor C, and continuously stirring.
6. 6. A method of applying the low moisture vapor transmission coating for a packaging material according to any one of claims 1 to 4, comprising the steps of coating the surface of a slip-sheet with the low moisture vapor transmission coating in an amount of 35g/m 2 , and drying to form a coating.

Description

Low-water vapor transmittance coating for packaging material and preparation method thereof Technical Field The invention relates to the technical field of packaging materials, in particular to a low-water vapor transmittance coating for a packaging material and a preparation method thereof. Background In the field of packaging materials, the coating technology is an industry with strict requirements on barrier property of packaging materials such as food, medicines and tobacco. Currently, packaging materials often employ metal coatings (such as aluminum) or organic polymer coatings to perform the function of blocking moisture and gases, but these conventional methods have significant drawbacks. Taking aluminized lining paper as an example, a metal layer is formed by physical vapor deposition, and although the water vapor transmittance can be effectively reduced to about 30 g/(m 2. D), the material difference between metal and a base material causes difficult recovery and degradation, and the environmental protection trend is violated. Meanwhile, the coating lacks a self-cleaning function, is easily attached by environmental pollutants, and influences the appearance and sanitation of the package. More seriously, under the condition of high-temperature processing or storage, the coating is easy to peel off or has poor high-temperature resistance effect, and the application of the coating in the heat sealing process is limited. At present, although the polymer coating can partially solve the problem of material uniformity, the traditional acrylic acid or polyurethane resin has insufficient water vapor barrier capability and cannot reach the ultra-low transmittance standard. Meanwhile, the surface energy of the coating is higher, the self-cleaning characteristic is difficult to realize, dust and oil dirt are easy to accumulate, and the practicability and the attractiveness of the package are reduced. The lack of high temperature resistance further exacerbates the problem, for example, the coating may soften or decompose during autoclaving or heat sealing, resulting in barrier failure. These defects not only affect the shelf life of the product, but also increase the complexity of production, for example, require additional processes such as film lamination or film lamination to compensate for the functional defects. At present, how to develop a coating with ultra-low water vapor transmittance, self-cleaning capability and excellent high temperature resistance, promote the packaging material industry to develop towards a sustainable direction, reduce the dependence on traditional non-degradable materials and become the technical problem to be solved at present. Disclosure of Invention The invention aims to solve the defects in the prior art, and provides a low-water vapor transmittance coating for a packaging material and a preparation method thereof. The low water vapor permeability coating for the packaging material comprises, by mass, 25-40% of modified polyurethane resin, 5-20% of a linear paraffin compound, 3-15% of a hydrophobically modified acrylic resin, 1-5% of amino-terminated polyamide amine, 1-5% of silica particles, 3-5% of hydroxyethyl cellulose, 0.1-0.5% of an amino curing agent, 1-3% of a water-based auxiliary agent and the balance of water. The low-water vapor permeability coating for the packaging material has the advantages that modified polyurethane resin, a straight paraffin compound, hydrophobic modified acrylic resin and amino-terminated polyamide amine are used as a coating architecture system, excellent water blocking effect is provided, meanwhile, good film forming capability is achieved, the hydrophobic modified acrylic resin, the amino-terminated polyamide amine and silicon dioxide particles form a stable micro-nano composite coarse structure, the water contact angle is greatly increased, the hydrophobic performance is enhanced, the waterproof performance is excellent, the dirt-proof and stain-proof effects are excellent, the hydroxyethyl cellulose is added, on one hand, the effect of filling gaps of the resin is achieved, on the other hand, the hydroxyethyl cellulose is used as a core for coating aggregation, the compactness of the hydroxyethyl cellulose is further improved, the water vapor permeability of an original system can be greatly reduced, the amino curing agent is added, the film forming curing temperature of the coating can be reduced, the surface baking state of the coating can be improved, the coating can be dried and rolled in a normal recommended plate temperature range, and the paper deformation and warping during coating rolling are prevented. Preferably, the aqueous auxiliary comprises at least one of ethanol, ethylene glycol, butyl ether and isopropanol. Preferably, the linear paraffin compounds include oxidized polyethylene linear paraffin compounds or/and aqueous polypropylene linear paraffin compounds. Preferably, the particle size of the modified polyurethane