RU2291882C1 - Insecticide packaging film - Google Patents

Abstract

FIELD: polymer materials.

SUBSTANCE: invention relates to technology of manufacturing films designed for packaging textile, leather, and fur industry products during storage and transportation periods. Film is made from biologically active layer based on insecticide-modified polyethylene and adhesively joined with reinforcing barrier layer. Film may be non-perforated or have through holes 0.2 to 2.0 mm in diameter. Insecticide-modified layer 10-30 μm thick is in a gel state and dispersion liquid thereof is insecticide or its solution in polyethylene plasticizer.

EFFECT: reduced film preparation laboriousness and enabled release of all introduced insecticides out of film.

2 cl, 2 dwg, 1 tbl

Description

The invention relates to the use of low molecular weight organic substances as components of compositions based on high molecular weight compounds. The compositions are intended for the manufacture of packaging films that have a layered structure and contain biocides released into the packaging space.

Light industry is in need of active packaging materials for products from natural fabrics, shoes, fur-fur semi-finished products, etc. Packages should provide barrier protection of goods from adverse environmental influences and mechanical damage, as well as prevent spoilage of goods by mold and keratophagous insects (moths, skin-eaters, carnivores, etc.).

There is an extensive collection of insecticidal preparations developed by the chemical industry, the current development trends of which are a complex mechanism of action (for example, preparations contain sublimating and volatile components [Patent application JP 62072601. Complex insecticidal material / Okano T. IPC A 01 N 25/18. Publ. 1987 1987 ]), stability at elevated temperatures and humidity, as well as low toxicity and "sparing" effects on metals and plastics [Patent application JP 62226906. Insecticide against fiber insect pest / Aikawa T. IPC A 01 N 65/00, 37/06. Publ. 1987].

The main problem of combining polymer films and insecticidal components is to determine the optimal structure of such films as packaging material. Optimality criteria - 1) the release of insecticides in the gas-vapor or liquid phases mainly inside the package, 2) the ability to remove moisture from the packaging space that evaporates from the packaged products. The latter factor is very important due to the fact that moisture condensation in itself can lead to damage to products made from natural materials that are hermetically sealed in a film. This problem is being addressed in several ways.

One of the first applications of biocidal films was realized using cellulose-based varnishes containing insecticides, odorizing substances, antiseptics, etc. [Patent GB 425974. Improvements in or relating to cellulose films / Petroff P.Ch. IPC S 08 K 5/00. Publ. 1935]. Currently, it has been transformed into the predominant use of emulsions, for example, based on a pyrethroid and an antioxidant, which additionally contain a solvent, thickener, emulsifier, antifoam [RF Patent 2108715. Insecticidal composition and packaging for containing the composition / Mile D. L., Fiard J. -F. IPC A 01 N 25/00, 25/04; B 65 D 65/46, 65/38. Publ. 1998].

Such materials, applied in the form of coatings on furniture, carpets, semi-finished fur products, etc., have received limited use. In film packaging for light industry products and in warehouses, polymer insecticidal compositions in the form of tablets are used. Patent [JP 7149601. Insecticide for closing insect pest / Muramoto T. IPC A 01 N 25/18. Publ. 1995] protects a transparent film container with openings containing a complex of biocides: a tablet made of a mixture of an insecticide and a sublimating substance that evaporates at room temperature, as well as a non-woven fiber element impregnated with an insecticide-reactive liquid. The evaporation of the insecticidal complex from the container occurs at an adjustable speed and the ability to control the reduction in tablet size. Tablets based on a polymeric binder (PVC, polystyrene, PMMA, etc.) and an insecticide based on pyrethroids [US Patent 6296865. Insecticide compositions made from polymer / Dujardin R., Bublitz M.-D., Neumann H. IPC A 01 N 25 / 18, A 01 M 13/00. Publ. 2001] used to create a controlled atmosphere in the premises. These tablets "work" when placed in heating devices at T = 120-190 ° C.

Such compositions have a rather narrow application because of the technical difficulties of the controlled release of insecticides. Modified by insecticide films are preferable, primarily due to the ability to individually protect each product and the simplicity of such protection.

Known sealing packaging film impregnated with pesticides or insecticides [Patent CA 1097131. Packaging material resistant to insect infestation / Heselev M. IPC A 23 L 3/34. Publ. 1981]. Insulation of the product into it with the help of hermetic welds eliminates the penetration of microorganisms and insects from the environment into the packaging.

The lack of film [Patent CA 1097131. Packaging material resistant to insect infestation / Heselev M. IPC A 23 L 3/34. Publ. 1981] - condensation inside a package of moisture evaporating from a product. This leads to a high probability of damage to the product by condensate and changes in the properties of the film due to adsorption on its active inner surface of water molecules.

This problem is to some extent solved by means of a packaging polyethylene film [Patent application BY, IPC С 08 К 5/00. Polymer packaging film / L.S. Pinchuk, A.V. Makarevich, G.M. Vlasova, V.E. Sytsko - Auth. 19990009; Claim 01/05/1999; Publ. 09/30/2000], which is filled with a peritroid class insecticide and starch. The particles of the latter, emerging on the surface of the film, absorb moisture, but most of them do not participate in the adsorption process after being "walled up" in the binder.

Actively acting on the environment polymer packaging film [Patent GB 1384941. Environment-affecting packages / gelanese Corp. IPC B 01 D 53/26, A 61 L 9/04, F 26 B 5/16. Publ. 1975] is equipped with a system of pores ranging in size from 100 to 1200 Å, which were formed in it during technological operations of stretching and subsequent annealing. When insecticides are adsorbed on the inner surface of the film package, they can migrate through the film and evaporate from its outer side. This happens if powdered insecticides are packaged in film. Film [Patent GB 1384941. Environment-affecting packages / gelanese Corp. IPC B 01 D 53/26, A 61 L 9/04, F 26 B 5/16. Publ. 1975] does not contain modifying insecticidal components.

The prototype of the invention is a two-layer packaging film [Patent JP 3007203. Complex insecticide, insect-killing method and packing material for the same insecticide / Takeda M. et al. IPC A 01 N 43/32, 25/18. Publ. 1991 (prototype)]. Its inner layer is obtained by extrusion of a composition consisting of a polyolefin and a mixture of insecticides (e.g. trioxane + empenrin). It is laminated with a film of the starting polyolefin and is provided with through holes passing through both layers.

The disadvantages of the prototype:

- the high complexity of manufacturing the film by coextrusion using a film unit containing a pair of extruders that process polymer compositions of different compositions;

- lack of effectiveness of the allocation of "walled" in a binder insecticide from the active layer of the film;

- the impossibility of combining in the technological process of manufacturing the film operations of coextrusion and perforation.

Tasks to be solved by the invention:

1) to develop a film structure with an active insecticidal layer, which would reduce the complexity of its manufacture;

2) to provide the possibility of controlled release from the film of the entire stock of insecticides introduced into it;

3) provide for the possibility of applying an insecticide to the walls of the holes in the film during its perforation.

The tasks are solved in that the known insecticidal packaging film, consisting of a biologically active layer based on an insecticide-modified polyolefin, and an adhesive-bonded reinforcing barrier layer of a polymeric material, has a new structure. Both layers are made in one non-perforated polyethylene film so that the insecticide-modified layer is in a state of jelly, the dispersion liquid of which is the insecticide or its solution in polyethylene plasticizer. The diameter of micropores in the polymer matrix of this layer is of the order of 1-10 μm and decreases normal to the film surface. The thickness of the gelatinous layer is from 10 to 30 microns, depending on the effectiveness of the insecticide, the pore diameter and the service life of the film packaging.

The second embodiment of the invention is that the above-described film has through holes with a diameter of 0.2 to 2.0 mm passing through the barrier and biologically active layer of the film.

The essence of the invention lies in the fact that the gel-like film layer is a porous polymer matrix, in the interconnected pores of which is a liquid insecticide. Pores are distributed in a matrix with a gradient over the film thickness: the pore diameter decreases in the direction from the film surface. This causes: firstly, the continuous release of the insecticide only from the gelatinous layer of the film; secondly, the isolation of micron-sized pores from the pores takes a long time and ends when the entire insecticide disappears from the system of communicating pores; thirdly, the system of emptied micropores having a large surface area inhibits moisture condensation in the form of droplets on the inner side of the film package.

The structure of the proposed film is the original and with through holes shown in figures 1 and 2, respectively.

The film in figure 1 consists of a non-porous barrier hardening, vapor impermeable insecticide layer 1 of polyethylene, which in layer 2 of thickness h is converted to a gelatinous state. Layer 2 has the structure of a porous polymer matrix, in the pores 3 of which is a liquid insecticide. The thickness of the gelatinous layer is selected in the range h = (1/5 ÷ 1/2) H, where H is the thickness of the packaging film to ensure:

1) sufficient diaper strength,

2) the impermeability of the non-porous film layer for insecticide vapor,

3) the supply of insecticide in the film, which determines the required service life of the package.

Figure 2 shows that the perforated film on the walls of the holes 4 within the jelly-like layer 2 has open pores 3, and the insecticidal liquid is adsorbed on the walls of the holes, forming a layer 5.

Here are examples of the implementation of the invention.

For the manufacture of films used high pressure polyethylene (LDPE, grade 15803-020, GOST 16337-77), plasticizer LDPE - dioctyl phthalate (DOP, GOST 8728-88), as well as liquid insecticides:

- permethrin (P, TU 6-00-5763450-78-88), a viscous liquid with a molecular weight of 391, a boiling point of about 200 ° C;

- cypermethrin (C), the empirical formula C ₂₂ H ₁₉ O ₃ NCl ₂ , the structural formula

tan liquid, molecular weight 416; in the examples, cypermethrin of the Nurell trademark of Dow Elanco Co.

Films of type I — non-perforated and type II — perforated, were made.

Type I film samples were obtained by sleeve extrusion according to the original technology developed by the authors: an insecticidal liquid of the following compositions was brought into contact with the sleeve, which is in the viscous-flowing state before the hardening line:

composition 1 - P + DOP in a ratio of 2: 1 by weight,

composition 2 - C + DOP in a ratio of 2: 1,

composition 3 - P + C in a ratio of 1: 1 by weight.

Depending on the level l of liquid above the mandrel of the extrusion head, a gelatinous insecticidal layer of various thickness h was formed on the inner side of the sleeve. The thickness of the films of the proposed structure was H = 70 ± 3 μm.

As a plasticizer for LDPE, other substances that are solvents P and C, for example cyclohexane, benzene, can be used.

The prototype film was obtained as follows:

1) an insecticidal film 30 μm thick was formed by sleeve extrusion from a LDPE composition (95 wt.%) + A solution in DOP (1.7%) of a mixture (1: 1) of P + C insecticides (3.3 wt.%);

2) similarly molded laminating film with a thickness of 45 μm from the original LDPE;

3) the laminating film was heated to a temperature of 105 ± 3 ° C and, using rollers, it was adhesively bonded to an insecticidal film to obtain a two-layer film 70 μm thick.

Type II film samples were obtained by perforating (at the corners of a square with a side of 1 cm) of type I film using punches having a diameter of d = 0.2; 1.0; 2.0 and d = 2.5 mm.

Studied the following parameters of the films.

The deformation-strength characteristics — tensile strength (σ) under tension and elongation (ε) at break were determined according to GOST 14236-81.

The strength (τ) of the weld formed at T = 140 ° C using a welding device was evaluated by delaminating the welded sample on a tensile testing machine.

The insecticidal effect of the films was studied with respect to the ward moth of Tineola biselliella. Moth caterpillars were grown in Petri dishes on agar-containing media. Then, samples of woolen fabric (3 × 3 cm) were placed in cups, which were inserted into open envelopes from the test film. After 30 days, the amount of tissue damage (p) and butterflies (n) in the cups was recorded.

Moisture condensation on the films was evaluated by the following procedure. A Petri dish with water (layer ~ 1 mm) was hermetically covered with the studied film sample and kept in a thermostat at Т = 50 ° С. After 4 hours, the following was recorded: the presence on the film surface of large drops of condensate (K), small drops (M) or the absence of drops (O).

The thickness of the gelatinous layer of the film containing the insecticide was determined on transverse sections of the samples using an optical microscope.

The test results are shown in table 1. Their analysis leads to the following conclusions.

1. The optimal level of 1 insecticidal liquid above the mandrel of the extrusion head during the formation of the proposed films is 3 mm <l ≤ 15 mm. For l <3 mm, technological inconveniences of control l arise; for l> 15 mm, the likelihood of a rupture of the film sleeve and insecticidal liquid entering the working area increases unacceptably. At optimal l values for the studied insecticides, the thickness of the gel-like layer of the type I film (samples 1-6) is within 10 μm ≤ h ≤ 30 μm. It can be seen from Table 1 that the value of h does not affect the insecticity of the films, and with an increase in h, the deformation-strength parameters of the films decrease slightly.

2. Samples 1-6 of type I of the proposed film are superior in deformation and strength characteristics and insecticidal, and in terms of weld strength they are not inferior to the prototype (sample 7). The superiority of samples 1-6 over the prototype in terms of insecticidal and moisture condensation is due to the fact that the insecticide is released from the gelatinous layer more intensively than from the composite layer of the prototype film. The condensation of moisture on the microporous surface of the proposed film is apparently accompanied by the penetration of moisture into the pores of the surface layer, and therefore by the absorption of moisture by the film.

3. The optimum range of hole diameters in type II films is 0.2 mm ≤ d ≤ 2.0 mm. Felling holes with a diameter of d <0.2 mm is associated with technological difficulties. Holes with d> 2.0 mm cause increased gas exchange between the packaging space and the environment, reducing the effectiveness of the insecticidal action of the films. Therefore, sample 11 has insufficient insecticidalness compared to samples 8-10 equipped with holes with d = 0.2 ÷ 2.0 mm.

4. Samples 8-10, 12, 13 of type II of the proposed film surpass the prototype (sample 14) in all controlled parameters. The deformation-strength characteristics and the strength of welds slightly deteriorated due to the perforation of the films, but remained at a high level of requirements for packaging materials.

5. Perforation of insecticidal films, made in accordance with the invention, slightly reduces their strength, but eliminates moisture condensation on the inner side of the film and increases the insecticidal properties of the package. This may be due to the removal of a film of water, which reduces the effectiveness of the insecticide, with the opening of micropores on the walls of the holes in the film and with the adsorption of insecticidal liquid on these walls.

It should be noted that the manufacturing process of the proposed films, ceteris paribus, is more technologically advanced than the prototype films, which, along with the above conclusions, determines the technical and economic advantages of the present invention. Films corresponding to the examples given in the application are certified by the State Institution "Republican Scientific and Practical Center of Hygiene" as not irritating to the skin of animals.

Thus, the tasks set during the creation of the invention are fulfilled.

Insecticidal packaging film will find application in the storage and transportation of light industry products. The economic effect of the use of the film is the sum of the effects of combining packaging and preservation of products, as well as from reducing losses due to its bactericidal damage.

Table 1 Sample Type No. of composition, values of l and d, mm Sample No. h, μm Deformation and strength characteristics The strength of the seam, τ, N / cm Insecticidal Moisture condensation σ, MPa * ε,% * R n one l = 3 mm one 10 14.0 / 10.02 891/983 8.4 0 0 to 5 2 10 13.33 / 9.72 933/990 8.2 0 0 to 10 3 twenty 12.21 / 9.03 987/995 7.9 0 0 m I l = 15 mm four thirty 11.87 / 8.78 993/1021 7.7 0 0 m 2 l = 5 mm 5 10 10.66 / 9.33 466/867 9.8 0 0 m 3 l = 5 mm 6 10 12.45 / 10.88 520/887 7.5 0 0 m prototype 7 - 11.74 / 9.58 471/853 7.5 one one to one d = 0.2 mm 8 13.00 / 9.51 941/991 8.1 0 0 0 1,0 9 10 11.97 / 8.72 952/995 7.5 0 0 0 2.0 10 10.55 / 7.73 959/997 6.4 0 0 0 II d = 2.5 mm eleven 9.97 / 7.21 971/1000 4.1 one one 0 2 12 10 10.55 / 8.57 477/974 8.7 0 0 0 d = 1.0 mm 3 13 10 11.19 / 9.73 527/891 6.7 0 0 0 d = 1.0 mm prototype fourteen - 10.53 / 8.50 473/859 6.6 one 2 0 d = 1.0 mm * the numerator shows the values of the parameters under tension along, and in the denominator - across the direction of sleeve drawing
** samples formed at l = 5 mm

Claims (2)

1. The insecticidal packaging film, consisting of a biologically active layer based on polyethylene modified with an insecticide, and an adhesive-bonded reinforcing barrier layer of polymeric material, characterized in that the film is non-perforated, both layers being made in one polyethylene film so that the insecticide-modified layer of 10-30 μm is in a state of jelly, the dispersion liquid of which is the insecticide or its solution in a plasticizer of polyethylene. 2. The insecticidal packaging film, consisting of a biologically active layer based on polyethylene modified with an insecticide, and an adhesive-bonded reinforcing barrier layer of polymeric material, characterized in that there are through holes in the film with diameters from 0.2 to 2.0 mm, which made in one polyethylene film so that the insecticide-modified layer of 10-30 microns is in a state of jelly, the dispersion liquid of which is an insecticide or its solution in plasticizer polyethylene a.

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