RU2203202C2 - Method of vacuum packing of goods - Google Patents

Abstract

FIELD: automotive industry; vacuum packing of precision articles for storing. SUBSTANCE: according to proposed method, articles 1 are placed on perforated pan 2 using supports 3 with cavity in upper part and vertical holes in central part of base and are covered with thermoplastic film with heating of film to temperature of highly elastic stage and evacuation of air from space between pan and film through vertical holes registered with holes of pan, after which film is cooled and connected with articles with adhesive backing. EFFECT: increased storage life of articles owing to provision of minimum parasitic amount of air inside package. 2 ex, 7 dwg

Description

 The invention relates to packaging technology, in particular to methods for packaging precision parts in a thermoplastic film.

 An analogue of the claimed invention is a method of packaging products under vacuum, which consists in placing them on a substrate, covering them with a thermoplastic film, heating the film to a softening temperature, evacuating the cavity between the substrate and the film, and cooling the resulting package. As the substrate, a thermoplastic polymer film or cardboard laminated with a polymer film is used (US Pat. No. 3,303,628, CL 53-22, 1967).

 The essential features of the analogue: “covering products with a thermoplastic film”, “heating the film to a softening temperature”, “vacuuming the cavity under the film” and “cooling the film” coincide with the essential features of the claimed invention.

 The known method is original and finds application in various industries, but when it is used, there is a low quality of the connection between the substrate and the film, since when vacuuming after heating, the upper film cools, which negatively affects the quality of the connection of the upper film with the substrate.

 The closest analogue of the invention to the problem to be solved and the technical result to be achieved is a method of packaging products under vacuum, including placing the products on a perforated tray, covering them with a thermoplastic film, heating the film to a softening temperature, evacuating the cavity between the tray and the film, cooling the film, applying a molded film with products on the substrate, reheating the film while evacuating the cavity between the film and the substrate and applying pressure to the outer surfaces and the last (a. p. 533 523 USSR, M. Cl. B 65 B 31/00, 1976).

 The essential features of the prototype: “placing the products on a perforated tray”, “covering them with a thermoplastic film”, “heating the film”, “evacuating the cavity between the tray and the film”, “cooling the film” and “connecting the formed film with the products with the substrate” coincide with significant features of the claimed invention.

 This method allows to obtain a sealed package with a strong connection of the upper film with the substrate. Due to the positive difference in the pressure of compressed air on the lower film relative to the upper film and the resulting air cushion, the bag with packaged products is prevented from sticking to the wall of the air chamber. However, a significant parasitic volume of air remains in the package, adversely affecting the shelf life of the products.

 The problem to which the invention is directed is to increase the shelf life of products by ensuring a minimum parasitic volume of air inside the container. Another type of technical result, the receipt of which can be achieved by the claimed invention in comparison with the closest analogue, is to simplify the method and expand the assortment of the used film.

 To achieve the technical result, the method of packaging products involves the operation of placing products on a perforated pallet using supports having a recess in the upper part and vertical holes in the central part of the base, covering them with a thermoplastic film, heating the film to a temperature of highly elastic state, evacuating the cavity between the pallet and the film through vertical holes in the central part of the base of the stands, combined with the holes of the pallet, cooling Ki and the compounds of the molded articles with a film with an adhesive backing.

 Significant distinguishing features of the prototype from the prototype are “placing products on supports with a recess in the upper part”, “heating the film to a temperature of a highly elastic state”, “evacuating the cavity between the pallet and the film through vertical holes in the central part of the base of the supports combined with the holes of the pallet” and “bonding the molded film to the adhesive backed products”.

 In FIG. 1 shows a stand with two vertical holes, a plan view; figure 2 is a section aa in figure 1; figure 3 - perforated pallet with sections: without stand, with stand and with the product placed on the stand; in FIG. 4 and 5 schematically depict a cylindrical product, side view, packed, respectively, by the claimed and known methods; in FIG. 6 and 7 show a packaged product, a transverse section, respectively, of the claimed and known methods.

 The invention is illustrated by the following description of the method of its implementation.

The packaged products 1 are placed on the supports 3 located on the perforated pallet 2 with a recess in the upper part, covered with a thermoplastic film, which is heated to a temperature of a highly elastic state. This temperature is different for each type of film and ranges from 85 to 180 ^o C. After that, the cavity is vacuumized between the tray 2 and the film through vertical holes in the central part of the base of the supports 3, combined with the holes of the tray 2, as a result of which the softened film tightly tightens packaged products 1. Then the film is cooled, the cooling time depends on the material and the thickness of the film. This completes the film formation. The formed film with products 1 is connected to the adhesive substrate, closing the gaps formed during the formation of the package.

 According to the known method (Fig. 5), the film 4 covers only the upper part of the product 1 and is lowered onto the pallet 2 with the holes uniformly located in it, leaving the lower part of the product unprotected. When welding the upper 4 and lower 8 films (Fig. 7), the free (parasitic) air volume 7 inside the container cell reaches ideally 13.7% of the product volume 1, in fact ~ 15%. In addition, at the first stage of packaging (evacuation), the film sticks in the holes of the pallet, making it difficult to separate the film with products from the pallet.

 According to the proposed method (figure 4), the holes in the pallet 2 and supports 3 are aligned and allow, due to the directed air flow, the softened film 4 to tightly tighten the upper and lower parts of the product 1. Only the lower surface of the product 1 conjugated with the stand 3 remains unprotected, while the air volume 6 of the cell is 7 ... 9% of the volume of the product 1 (depending on the shape of the product and the thickness of the stand), in fact - 5 ... 6%, since when connecting the film 4 with the adhesive substrate 5 (Fig.6 ) the latter is glued directly to the product 1, by to the free air volume within the container cell is further reduced by approximately 30%, i.e., there is, with the proposed method, a reduction in parasitic volume 6 after two operations by a factor of 2. .. 3 times compared with the known method, which ensures reliable storage of precision fuel equipment items for at least 5 years under storage conditions 2 (C) according to GOST 15150-69. This is confirmed by climatic tests of the packaging made by the claimed method, conducted by the Testing Center of the Kaluga Research and Development Institute of Packaging and Packaging.

 Specific examples of the method.

Example 1
The nebulizers 1 are placed on supports 3, covered with 450 μm thick polyethylene terephthalic amorphous film (TU 2255-437-05761784-2000), heated to a temperature of 90-100 ^o C, the cavity is evacuated between tray 2 and the film to 600 mm Hg . for 30-35 s, while heating the film continues for 10 s from the beginning of the vacuum. Then the film is cooled for 15 s and the packing slots are sealed with a PVC label with an adhesive layer (TU 6-00-04696843-08-93).

Example 2
The packing of the plunger pairs is carried out analogously to example 1, only the film is used with a thickness of 350 microns (TU 6-49-576183-90), it is heated to a temperature of 85-95 ^o C and after the cessation of heating create a vacuum up to 550 mm Hg for 20-25 s. 10 seconds are enough to cool the film.

 So, by increasing the temperature of heating the film to a highly elastic state and evacuating the space between the tray and the film through the holes in the supports, the proposed method allows to reduce the parasitic volume of air in the package and, therefore, increase the shelf life of the products.

Claims (1)

 A method of packaging products under vacuum, comprising placing them on a perforated tray, covering them with a thermoplastic film, heating the film, evacuating the cavity between the tray and the film, cooling the film and connecting the molded film to the products with a substrate, characterized in that the products are placed on supports with a recess in the upper part, the film is heated to a temperature of a highly elastic state, evacuation is carried out through vertical holes in the central part of the base of the supports, combined e apertured tray with preformed film is connected to the adhesive substrate.

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