CS261667B1 - Mixture for preparing a polyolefin-based auto-adhesive film with controlled adhesive diffusion - Google Patents

Abstract

The purpose of the mixture for preparing a self-adhesive film based on polyolefins with controlled diffusion of the adhesive is to increase the self-adhesion of packaging films. The stated purpose is achieved by using 95 to 99.75 wt. % polyolefin, 0.025 to 4.5 wt. % oxyethylated castor oil and 0.025 to 4.5 wt. % natural rosin or triabietate glyceride. The mixture for preparing a self-adhesive film based on polyolefins with controlled diffusion of the adhesive is used in the packaging industry

Description

261667

The present invention relates to a composition for preparing a polyolefin-based auto-adhesive film with controlled adhesive diffusion.

The hitherto known auto-adhesive fixing films are based on polymers such as polyethylene (low- and medium-density types), polypropylene, polyvinyl chloride, and the like. copolymers such as ethylene-vinylacetate copolymer, by additive treatment with agents that provide repeated autoadhesion of the foil backing. A known autoadhesive additive is, for example, polyvinyl butyral, which is 0.05 wt. % is added to the branched polyethylene, but the autoadhesion of the resulting blend is relatively low. An increase in the adhesion of the polyethylene films can also be achieved by the addition of 1 wt. % polypropylene glycol, respectively. propylene oil to polyethylene. Autoadhesion of the resulting films does not exceed 4 N.cm -1. Modification of Polyethylene 5 wt. The% atactic polypropylene also increases foil autoadhesion. However, the necessary autoadhesion is achieved in the long term (months) and the physical-mechanical properties of the films are not satisfactory.

Natural pimaric acid or abietic acid-based colophones, such as other resins, such as formaldehyde, cumsulfate, have been used as one of the components of rubber-based solution adhesives. After the application of these adhesives, for example, with metals, the solution adhesive was evaporated and then another surface was prepared and glued [M. Osteen: Working with lepidlya mastics, SNTL, p. 79 (1982)]. These bond a relatively high strength, but polyethylene and polypropylene stick in this way. A further disadvantage is that the bonding is laborious, harmful to health and sometimes the type of solvent (acetone, toluene, solvent benzene) creates a danger of explosion, respectively. after-fire.

The colophony itself in admixture with polyolefin does not increase adhesion, and the physical-mechanical properties of the polymer deteriorate. For these reasons, colophony has not yet been used for the preparation of autoadhesive packaging films.

The above drawbacks are substantially hindered by the polyolefin-based autoadhesive adhesive-based autoadhesive film composition, which consists in a mixture of 95 to 99.75 wt. % of polyolefin, 0.025 to 4.5 wt. % of oxyethylated castor oil and 0.025 to 4.5 wt. natural colophony or glycidate of the triabietate. The advantage of the polyolefin-based autoadhesive-based blend with controlled diffusion is its simplicity, good processability, economic advantage over the films used so far, and the fact that no change in technology is required, nor does the modification of existing foils produce the films in question. The desired adhesion effect is achieved according to the proposed solution due to the synergistic effect of the low molecular weight system and the resin. The binary system also has the additional condition that it is physically intolerable with the polymer matrix, which makes it possible to achieve that even a relatively small amount of the additive applied in the mass, which does not deteriorate the physico-mechanical properties of the film, makes it possible to significantly influence the surface properties of the film due to controlled diffusion in particular, increase autoadhesion. Example 1

50 wt. oxyethylated castor oil and 50 wt. % natural colophony. The resulting mixture is boiled at 135 ° C for 10 minutes. It is then mixed with the same amount of powdered branched polyethylene and homogenized in a mixer. 2.5 g of the thus prepared concentrate are added to 997.5 g of branched polyethylene granulate, mixed at 170 DEG C. in an extruder and 0.04 mm rakes are prepared using a slit nozzle. Foil autoadhesion is 11.6 N. cm ”1.

Example 1 and 2

The procedure is as in Example 1 except that the triabietic glyceride (A-biester 90) is used. Film autoadhesion is 11.2 N. cm’1. Example 3

The procedure is as in Example 1, with the difference that 40 g of the concentrate is added to 1860 g of branched polyethylene granulate. The film self-adhesion is 10.8 N. cm -1

The procedure is as in Example 3, except that the glyceride is used as the triaietate. The autadadhesion of the prepared film is 10.4 N. cm’1.Example 5

The procedure is as in Example 1, except that 200 g of the concentrate is added to 1800 g of branched polyethylene granulate. The autoadhesion of the prepared film is 10.6N. cm’1. Example 6

The procedure is as in Example 5, except that the glyceride is used with the triabetate. The adhesion of the prepared film is 10.2 N.cm -1

The procedure is as in Example 3,

Claims (1)

SUBJECT A composition for the preparation of a polyolefin-based autoadhesive film with controlled adhesive diffusion, characterized in that it consists of 95 to 99.75 wt. % of polyolefin, 0.025 to YNAIEZU 4.5 wt. % of oxyethylated castor oil and 0.025 to 4.5 wt. % natural rosin or triabietate glyceride.