CS261435B1 - A composition 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. % dibutyl phthalate 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

The present invention relates to a composition for the preparation of a β-polymorphite-based utoadhesive film with controlled diffusion of the adhesive.

The previously known self-adhesive fusible packaging films are made on the basis of polymers such as polyethylene (low- and medium-density types), polypropylene, vinyl chloride poles, resp. copolymers, such as ethylene-vinyl acetate copolymer, by additivating with agents that provide repeated autoadhesion when the film is pressed. A known autoadhesion-promoting additive is, for example, polyvinylbutyral, which is 0.05 wt. % to the branched polyethylene, but the autoadhesion of the film prepared from the resulting mixture is relatively low. An increase in the autoadhesion of the polyethylene films can also be achieved by adding 1 wt. % Of polypropylene glycol or propylene oil, respectively, to polyethylene. The autoadhesion of the resulting films does not exceed 4 N. cm * ¹ . Polyethylene modification 5 wt. % of the atactic polypropylene also increases the autoadhesion of the films. However, the necessary autoadhesion is achieved over a longer period (months) and the physico-mechanical properties of the films are not satisfactory.

Natural rosin based on α-pimaric acid or abietic acid as well as other resins, e.g. formaldehyde, coumarone, were used as one of the ingredients of the raisin rubber adhesives. After repeatedly applying these adhesives to, for example, metals, the solution adhesive was evaporated and then the prepared other surface was pressed and glued [M. Thorn: Working with adhesives and sealants, SNTL p. 79 (1982)]. These joints have a relatively high strength, but in this way polyethylene and polypropylene cannot be bonded. Another disadvantage is that the bonding is laborious, harmful to health and sometimes according to the type of solvent (acetone, toluene, solvent gasoline) there is a risk of explosion, resp. fire.

The rosin in admixture with the polyolefin alone does not increase the adhesion and at the same time deteriorates the physico-mechanical properties of the polymer. For these reasons, the colophony used to prepare autoadhesive packaging films has not yet been shallow.

The above-mentioned disadvantages are substantially eliminated by the polyolefin-based autoadhesive film preparation with controlled diffusion of the adhesive, which consists in that the mixture consists of 95 to 99.75 wt. percent polyolefins, 0.025 to 4.5 wt. % dibutyl phthalate and 0.025 to 4.5 wt. % natural rosin or trlabietate glyceride.

The advantage of the diffusion-controlled polyolefin-based auto-adhesive film composition is its simplicity, good processability, economic advantage over previously used films, and the fact that there is no need for a change in technology or modification of existing equipment for producing the films in question.

According to the proposed solution, the desired adhesion effect was achieved due to the synergistic effect of the low molecular weight substance and resin system. The binary system spins and further reminds that it is physically incompatible with the polymer matrix, which makes it possible to achieve that even a relatively small amount of the additive applied in the mass, which still does not compromise the physico-mechanical properties of the film, the properties of the film, in particular to increase the autoadhesion.

Example 1

50 wt. percent dibutyl phthalate and 50 wt. ° / o natural rosin. The resulting mixture was boiled at 135 ° C for 10 minutes. It is then mixed with an equal amount of branched polyethylene powder and perfectly homogenized in a mixer, 2.5 g of the concentrate thus prepared is added to 1 997.5 g of branched polyethylene granulate, mixed at 170 ° C in an extruder and prepared by a slot die. foil thickness 0.04 mm. The autoadhesion of the film is 10.2 N. cm ^-1 .

Example 2

The procedure is as in Example 1, except that glyceride triabietate (Abiester 90) is used. The autoadhesion of the film is 10.0 N. cm ^-1 .

Example 3

The procedure is as in Example 1, except that 40 g of concentrate is added to 1,960 grams of branched polyethylene granulate. The autoadhesion of the prepared film is 12.0 N. cnr ¹

Example 4

The procedure is as in Example 3, except that glyceride triabietate is used. The autoadhesion of the prepared film is 11.5 N. cm ^-1 . Example 5

The procedure is as in Example 1, except that 200 g of concentrate is added to 1,800 g of branched polyethylene granulate. The autoadhesion of the prepared film is 10.6 N. cm ¹ .

Example 6

The procedure is as in Example 5, except that glyceride triabietate is used. The autoadhesion of the prepared film is 10.4 N.

. cm ¹ .

Example 7

The procedure is as in Example 2, except that 10 wt. % dibutyl phthalate and 90 wt. % natural rosin. The autoadhesion of the resulting film is 11.6 N. cm ^-1 .

Example 8

The procedure is as in Example 7, except that glyceride triabietate is used. The autoadhesion of the prepared film is 11.2 N. cm ^-1 .

Example 9

The procedure is as in Example 3, except that 90 wt. % dibutyl phthalate and 10 wt. % natural rosin. The autoadhesion of the prepared film is 11.0 N. cm ^-1 .

Example 10

The procedure is as in Example 9, except that glyceride triabietate is used. The autoadhesion of the prepared film is 10.6 N. cm ^-1 .

Prikuad 11

The procedure is as in Example 3, except that isotactic polypropylene is used. The foil produced has an autoadhesion of 11.5 N. cm ^-1 .

Example 12

The procedure is as in Example 11 except that glyceride triabietate is used. The autoadhesion of the prepared film is 11.2 N. cm ^-1 .

The invention can find use in the packaging industry in the manufacture of packaging films and their use in group packaging of products on pallets and in the packaging of individual products.

Claims (1)

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. % polyolefin, 0.025 to ynAlez 4.5 wt. % dibutyl phthalate and 0.025 to 4.5 wt. % natural rosin or triabietate glyceride.