Patent display(7) Polyester polyols for retort-resistant packaging adhesives

Technical field

The present invention relates to a Polyester Polyol, particularly to polyester polyols for packaging adhesives.

Background

Packaging materials, especially composite packaging materials that are currently widely used, often use adhesives. Adhesive is a glue that can bond a single layer to form a multi-layer board, and is an important auxiliary material for the packaging industry

There are many types of adhesives and packaging materials. Generally speaking, packaging materials are divided into paper-based materials, plastics, wood, aluminum foil, etc, the most commonly used plastic materials are also divided into PP, PE, PET, PVC, etc, those skilled in the art choose the appropriate adhesive through the different packaging materials selected. For example, when bonding paper-based materials, starch paste, dextrin and other adhesives are generally used; When bonding plastics, resin types of adhesives are generally used, such as thermoplastic resin polyurethane, polystyrene, polyacrylate, etc.

When the adhesive is in a raw state, the viscosity is weak, and only after curing (that is, heating to a certain temperature) can it become a strong and strong substance with high bond strength. In general, after the raw state of the adhesive is mixed with the corresponding additive, the mixed slurry is transported by the pump to the corrugating machine, and then the corrugating machine is coated to the packaging film that needs to be bonded, and the two (or more layers) of the packaging film are superimposed and initially formed by extrusion of the high-temperature roller, and finally placed at a certain temperature to mature to stabilize the bonding together.

Today's society demand for composite packaging is increasing, due to the various packaging forms of the requirements of the adhesive material is different, and the requirements for adhesives are getting higher and higher, some of the existing adhesives can not achieve a better bonding effect. Especially for the adhesive applied to the packaging material of the food that needs to be steamed, the adhesive basically does not meet the requirements, that is, it cannot maintain a certain adhesion force at the cooking temperature, and the peeling strength is low.

Contents of the Invention

To solve the above technical problems, the present invention provides a polyester polyol, the raw material formulation by weight comprises:

36.2% to 42.2% polyols, 57.8% to 63.8% polyacids, synthetic additives including antioxidants and catalysts; The polyol is a mixed polyol, comprising ethylene glycol, diethylene glycol, neopentyl glycol and trimethylolpropane; The polyaccharides are mixed polyacids, including adipic acid, isophthalic acid and phthalic anhydride; The catalyst is a composition comprising bismuth nitrate with tetraisobutyl titanate or tetraisopropyl titanate.

In the above technical solution, the raw material for the production of polyester polyols is a mixed polyol and a mixed polyacid, and the additives added during production include antioxidants and catalysts, the amount of these two additives added is a conventional amount well known to those skilled in the art. In one particular embodiment of the present invention, the amount of antioxidant and catalyst added is 110PPM-130PPM and 120PPM-140PPM of the total weight of the raw material formulation.

Polyester polyols made from the above technical solutions can be used as the main agent to make adhesives for packaging.

After a large number of experimental studies, the inventor obtained the above technical solution, that is, the use of specific mixed polyols and mixed polyacids as raw materials, and the addition of a specific catalyst to obtain polyester polyols is particularly suitable for the production of adhesives, the resulting adhesives have very good properties.First of all, the resulting adhesive has very good cooking resistance after curing; Secondly, not only the adhesion performance after curing is excellent, but also has a certain degree of adhesion when curing the pregenic state, which can ensure that the packaging film to be bonded will not be staggered with each other during processing;In addition, packaging materials of various materials can be applied, such as aluminum-plastic, plastic-plastic bonding can achieve good bond strength; Finally, the polyester polyols using the above technical solutions and the further adhesives are viscous liquids at room temperature, making the process of making packaging materials easier.

Bismuth nitrate in the said catalyst can be mixed in any proportion with tetraisobutyl titanate or tetraisopropyl titanate. In one particular embodiment of the present invention, the mass ratio of bismuth nitrate to tetraisobutyl titanate in the catalyst is 8:5.

As a further improvement of the above technical scheme, the mixed polyacids adipic acid, isophthalic acid and phthalic anhydride account for 18.4% to 20.4%, 18.4% to 20.4%, 21% to 23% of the total weight of the raw material formulation, respectively.

As another improvement of the above technical scheme, the mixed polyols of ethylene glycol, diethylene glycol, neopentyl glycol and trimethylolpropane account for 11.8% to 13.8%, 20.7% to 22.5%, 2.6% to 4.6%, 1.1% to 1.3% of the total weight of the raw material formulation, respectively.

The antioxidant is triphenyl phosphite.

The present invention further provides a method of production of the polyester polyol, wherein the production method is a nitrogen pressure reduction method, the method is a method commonly used in the production of polyester polyols known to those skilled in the art.

The present invention also provides a packaging binder which is made of the above-described polyester polyols. Conventional methods familiar to those skilled in the art are used to prepare a packaging adhesive with polyester polyols.