SU1806159A3 - Adhesive composition for glueing together polymer films and aluminium foil - Google Patents

Description

The invention relates to the field of obtaining two-component adhesive systems based on polyurethanes and can be used for the manufacture of multilayer materials from polymer films and aluminum foil with increased adhesive strength for various purposes, more often for packaging food products subjected to sterilization.

The purpose of the invention is to obtain an adhesive composition with high adhesive strength and sterilization resistance of gluing aluminum foil with polymer films.

This goal is achieved by the fact that in the mortar adhesive composition, including isocyanate-containing and hydroxyl-containing components, a low-viscosity prepolymer with terminal isocyanate groups based on diphenylmethane diisocyanate and polyoxypropylene glycol is used as an isocyanate-containing component, a mixture of 500 with the following ratio of components, parts by weight:

Prepolymer based

4,4'diphenylmethane diisocyanate and polyoxypropylene glycol 27.5-29.5 A mixture of complex polyols with MM 500 and 2000 20.5-22.5 Solvent (ethyl acetate) 45.0-50.0 Use of a prepolymer based on 4.4 in the adhesive composition -diphenylmethane diisocyanate and polyoxypropylene glycol with MM 200-1000 allows to obtain a low-viscosity system with a high content of non-volatile substances (dry residue). Compared to the prototype, it is reduced by. 15-20% solvent content and is 45-50% in the glue versus 60-70% in the prototype, while ensuring the technological properties of the system necessary for processing

Xv o o

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I topics such as conditional viscosity and pot life, tab. 1.

The use of a mixture of complex polyols with different MW as a hydroxyl-containing component, in combination with the specified prepolymer, provides a sufficiently high adhesion and resistance of the adhesion to sterilization.

The invention uses an isocyanate-terminated prepolymer which is prepared by reacting

4,4-diphenylmethane diisocyanate and polyoxypropylene glycol (TU 6-05-1854-78). The synthesis is carried out at a ratio of NCO: OH = = 1.8-2.2: 1.0.

A mixture of glycol-based polyols (ethylene; butylene glycol or their mixtures) and polycarboxylic acids (TU 6-05-221-492-79 and TU 6-05-221-687-86) is used as a hydroxyl-containing component of the adhesive formulation. Solvent - ethyl acetate, GOST 2230-76.

For experimental verification of the claimed adhesive composition, 11 formulations were prepared (see table).

The glue was obtained by mixing the starting components in a certain ratio. On an aluminum foil with a thickness of 70110 microns with a primer layer, an adhesive composition with a thickness of 8-12 microns was applied using an applicator, squeegee or other device. After removing the solvent from the adhesive layer by drying with heated air, the foil with the adhesive layer was backed up with a polypropylene film 5070 μm thick using heated rolls (the temperature of the stitching roll is 70 ± 10 ° C).

Curing was carried out at room temperature, after 7 days of gluing were tested for adhesive strength and resistance to sterilization, in distilled water at T20 ° C for 60 min.

The relative viscosity of the glue was determined using a VZ-246 viscometer (nozzle 4), the adhesive strength of the bonds was estimated by the value of the peeling strength, the resistance of the splices to sterilization was estimated by the value of the peeling strength immediately after the end of sterilization.

The data given in the table are confirmed by the test report for adhesives (Al foil / polypropylene film) obtained using the listed adhesive formulations attached to this application.

Composition 1 corresponds to the prototype. Composition 2, in terms of its constituent components, corresponds to the prototype, but the solvent content in it corresponds to the claimed recipe, i.e. 20% less than in the prototype (50% versus 70% in the prototype). Compositions 3-5, 10 correspond to the invention, compositions 6-9, have exorbitant ratios of components, composition 11 - an exorbitant amount of solvent.

With an optimal ratio of components, compositions 3-5 and 10, the adhesive system has good technological properties (relative viscosity, pot life) and adhesive characteristics (peeling strength before and after sterilization) due to the complete passage of the adhesive joint polymerization process.

With an increase against the optimal content of the isocyanate component, compositions 8 and 9, the pot life of the glue and the resistance to sterilization of the glue line sharply decrease due to the production of a more rigid polymer.

With an increase against the optimal content of the hydroxyl-containing component, compositions b and 7, the adhesive strength of the bonds and the resistance to sterilization decrease due to incomplete passage of the curing process of the adhesive joint.

With an exorbitant (reduced) solvent content in the system, the conditional viscosity of the glue increases, which makes it difficult to process it according to optimal modes.

Claims (1)

Claim An adhesive composition for gluing polymer films with aluminum foil, including an isocyanate-containing component, a hydroxyl-containing component and ethyl acetate, characterized in that, in order to increase the adhesive strength while reducing the solvent content in the adhesive without changing its viscosity, it contains a prepolymer based on polyoxypropylene glycol and 4,4'-diphenylmethane diisocyanate, and - as a hydroxyl-containing component - a mixture of polyester polyols with a mol.m. 500 and 2000 at a mass ratio of 1: 2, respectively, with the following ratio of glue components, parts by weight: Prepolymer based on 4,4'-diphenylmet; andisocyanate and polyoxypropylene glycol 27.5-29.5 A mixture of polyester polyols with a molecular weight of 500 and 2000 at mass ratio 1: 2 respectively 20.5-22.5 Ethyl acetate '45.0-50.0. <0 H - 1 s c cm r - s oΐ 1 cm s cm s X - 1 cm w s o o <0 cm С _l о сm to 1 - ° СО о с с г- сч м Т “l ten in O. from r- '1 mid O' . cm * nt mid ten G ten O O O O 1 • O' ten <about about g - ten h with oh oh O <Oh with oh oh g- 1 o g ~ σί yag O G E O Η φ Mp α ϋ X O b wasps d a> <u with 3 ς Λ a ζ 3 • 3 and with to ν = τ <D with; ο 3 Q φ s ό X C <0 «J ... s m Η ο ο Σ Ci ω Σ σ> > C