Preparation method of a high strength yellowing resistant sewing adhesive

　　Due to the long-term impact of water stains, oil stains, and mold, household kitchen and bathroom decoration requires high requirements for waterproofing, oil resistance, scratch resistance, and mold resistance in terms of durability and aesthetics. Currently, there are a wide variety of household kitchen and bathroom decoration adhesives on the market, among which two component epoxy adhesives are widely used.

It has good mildew resistance and high strength, but its disadvantages are troublesome construction, poor water resistance, and is prone to yellowing, especially due to the problem of yellowing. Therefore, it is difficult to use for sealing the gaps in kitchen utensils and sanitary ware with light color and high whiteness. Therefore, it is necessary to provide a beautiful seam adhesive with good yellowing resistance, water resistance, excellent adhesion, simple construction, and good mildew resistance.
In order to overcome the shortcomings of the prior art, technicians provide a high-strength, yellowing resistant seam adhesive that has the characteristics of high strength, excellent adhesive performance, resistance to yellowing, and good mildew resistance. The following technical scheme is adopted to achieve it: The yellowing resistant high-strength polyurethane seam adhesive is composed of a specified material through a certain mass percentage of components. The modified molecular sieve consists of a limited mass percentage of components. The preparation method of modified molecular sieve is as follows: drying the activated powder of the molecular sieve to remove moisture, then mixing with a curing agent and standing for more than 24 hours, and then drying the surface of the molecular sieve to remove the curing agent attached to the surface to obtain modified molecular sieve.
When making this sewing adhesive, it should be noted that the polyurethane prepolymer consists of polyols, plasticizers, polyisocyanates, catalysts, chain extenders, and other components in a certain mass percentage. Polyisocyanates are aliphatic isocyanates, and polyisocyanates are one or more of isophorone diisocyanates, hexamethylene diisocyanates, or trimers thereof, dicyclohexylmethane diisocyanates, or 1,4-cyclohexane diisocyanates.
The adhesive prepared by the reaction of aliphatic isocyanates with polyols is not prone to yellowing, has good water resistance, and has high strength. Polyols are one or more of polyoxyethylene polyols, polyoxypropylene polyols, or polyester polyols. The plasticizer is one or more of aliphatic diacid esters, phosphate esters, epoxy soybean oil, or epoxy fatty acid methyl esters in an unlimited proportion. The reinforcing filler consists of one or more of talc powder, kaolin, heavy calcium carbonate, light calcium carbonate, active nano calcium carbonate, titanium dioxide, barium sulfate, kaolin, or silica powder in any proportion.
Compared to the prior art, the preparation method of the seam adhesive has the following beneficial effects: the seam adhesive prepared by the reaction of aliphatic isocyanates and polyols is not prone to yellowing, has good water resistance, and has higher strength. In addition, the modified molecular sieve obtained by modifying the active powder of molecular sieve with small molecular aliphatic diamine is mixed with other components to produce a one-component polyurethane seam adhesive.
The method provided by the present invention separates the curing agent from the polyurethane prepolymer, ensuring the storage stability of the entire component; When in use, each component is extruded, molecular sieves absorb water, replace small molecular aliphatic diamine curing agents, and react with polyurethane prepolymers to cross-link and solidify to form urea bonds. The curing speed is fast, the reaction is fast, and no bubbles are generated; The polyurethane adhesive prepared has high strength, excellent yellowing resistance, good scratch resistance, and strong mildew resistance, especially suitable for household use.