AU629527B2

AU629527B2 - Food packaging resistant to perforation by insects

Info

Publication number: AU629527B2
Application number: AU28475/89A
Authority: AU
Inventors: Giorgio Domenichini; Marco Pagani
Original assignee: Consiglio Nazionale delle Richerche CNR
Current assignee: Consiglio Nazionale delle Richerche CNR
Priority date: 1987-07-13
Filing date: 1989-01-13
Publication date: 1992-10-08
Anticipated expiration: 2009-01-13
Also published as: GR3005861T3; EP0299574B1; DE3874992T2; ATE81095T1; IT1222020B; IT8721264A0; DE3874992D1; ES2034164T3; AU2847589A; EP0299574A2; EP0299574A3; JPS6467327A

Abstract

The food-product packaging resistant to perforation by insects according to the invention comprises a container made of sheet packaging material compatible with the product to be packed or wrapped and with use thereof, the surface of the material facing the exterior of the packed container presenting a uniform distribution of rough portions having small dimensions and totally covering the surface and made of synthetic material not eatable by insects, preferably forming a down. It has been found that the down effectively withstands efforts of insects to penetrate containers constructed of material according to the invention.

Description

629 OF AUSTRALIA PATENTS ACT 1952-69 COMPLETE SPECIFICATION

(ORIGINAL)

Class Application Number: Lodged: Int. Class Complete Specification Lodged: Accepted: Published-.

Priority: Related Art Name of Applicant: Address of Applicant: Actual Inventor: Address for Service; CONSIGLIO NAZIONALE DELLA RICERCHE Piazzale Aldo Moro 7 Roma (Italy) GIORGIO DOMENICHINI and MARCO PAGANI EDWD. WATERS SONS, 50 QUEEN STRE~ET, MELBOURNE, AUSTRALIA, 3000.

Complete Specification for the Invention entitled: FOOD PACKAGING RESISTANT TO PERFORATION BY INSECTS The following statement Is a full description of thIs invention, Including the best method of performing It known to U Food packaging resistant to perforation by insects.

The invention relates to material for packaging food products and resistant to perforation by insects.

Protection of packaged goods is a particularly important aspect of the problem of preservation thereof.

Packaging is Important not only for food products sold at the end of the processing cycle but also for products which are stored between processing steps, often for very long periods, in containers such as 1, 1 0 bags or cardboard boxes or the like.

0 0 In order to prevent the packaged goods from being damaged by infesting insects, it would be desirable to reduce the storage periods to a minimum, but even when this is possible, sometimes a few days or even a few hours are sufficient for some insects which feed on the goods to eat their way through apparently insuperable barriers, In many cases, furthermore, goods are stored for weeks or months in depots exposed to attack by nut ous species of insects.

Since these products are to be used as food, the problem is to protect them without subsequent chemical disinfestatlon, which would replace one form of food contamination by another.

Storage places can be disinfected by fumigation, but in most cases these places cannot remain sealed. This is the case e.g. in supermarkets where boxes, packets and bags are practically uncovered, cn display to the public.

Under these conditions, only sealed packaging of glass or metal of sufficient thickness would be capable of protecting the goods from insects, but these materials are bulky, expensive and often inconvenient to use.

j 2 The food industries generally use packaging consisting of films of synthetic material such as polyethylene, polyvinyl chloride (PVC) and the like, and also in various combinations, but the resistance to insects of all these materials is partial and temporary and it is not always acceptable for them to be in contact with substances for useasfood.

Non-biodegradable synthetic substances are also undesirable as packaging material, particularly for food and products in wide use, owing to the effect on the environment when they are thrown away, Paper is suitable for this purpose since it dies not leave toxic molecules in food, but is extremely weak as a barrier against insects. The 1 0 problem of perforation of food packaging by insects is particularly important in temperate or subtropical countries, where insects have their greatest reproductive power, with serious consequences on the preservation of food.

The object of the invention therefore is to provide a material far wrapping and packaging food products which is compatible with the use of the packed substances as 1 5 food and is resistant to penetration by insects and is inexpensive and easy to use.

The invention therefore provides food-product packaging resistant to eating by insects, characterised in that said packaging comprises a sheet packaging material compatible with the product to be packed or wrapped and with use thereof, the entire surface of the material having adhered thereto a down of synthetic material, inedible to insects, thereby providing a uniform distribution of rough portions, as hereinbefore defined, having dimensions substantially smaller than the size of an attacking insect.

In this specification and the claims the term "rough portions" may be defined as any unevenness, scales, projection, protrusions or the like which constitute an 25 obstacle to gripping of the material facing the exterior of the packed container by insects.

Preferably the rough portions have dimensions substantially less than 50 ltm.

Preferably, the down is made up of spun synthetic fibre between 5 and im in diameter and having a length between 20 and 100 times the fibre diameter, bonded oo 30 to the sheet of packaging material by an adhesive and having a sufficient density, relative to the size of fibre, to at least completely cover the surface.

Advantageously, the down has a fibre density between 10 and 100 g/m 2

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!f m 3 Optionally, the sheet of packaging material is of paper having mechanical characteristics adapted to the material for insertion into the container and to the size thereof. Alternatively the sheet can be of cellophane or the like or of any other packaging material.

In a preferred embodiment the down is made up of 1.5 denier polyamide resin fibres (about 12 jpm in diameter) and 0.6 mm long, the density of fibres on the surface being between 50 and 80 g/m 2 and the fibres being bonded to the sheet of packaging material by an acetovinyl adhesive.

Optionally, the material forming the surface roughness is applied to a 1 0 surface of the sheet packaging material before packaging the container, so that the coated surface faces the exterior of the packaged container. Alternatively the material forming the surface roughness is applied to the outer surface of the container after

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packaging, depending also on the method of manufacturing the container and the geometrical characteristics thereof, Materials in sheet form having a downy surface can be obtained by depositing coats of fibres of constant length, electrostatically charged, on to a sheet the surface of which is covered with adhesive and underneath which a magnetic means Is disposed. Under these conditions the coats are all! disposed substantially vertically on the surface of the sheet and remain bonded thereto by the adhesive, thus producing a velvet-like material also called "flock".

The method can be applied to sheet material before packaging or to the container after packaging; the choice between the two possibilities will depend on the geometrical shape of the container.

When the method is applied after packaging, the container must be such that the coat can be deposited over its entire surface without leaving even the smallest parts uncovered, since they would be attacked and perforated, In the case where a sheet is used for packaging after the down has already been formed, the packaging must have a shape such as to ensure complete closing without the surface of the down interfering with the adhesion between the closing edges.

Cellulose materials such as paper or cellophane are advantageous, particularly for ecological reasons, for forming the packaging sheet which has to beglven a downy surface, These materials are economic and compatible with food products.

From the ecological viewpoint, after the biodegradable supporting layer has disintegrated, the down bonded thereto breaks up without substantially polluting the environment.

~I In general, the resistance of "flock" material to insects depend on the material and thickness of the supporting sheet and on the material forming the surface down.

The resistant of packaging according to the invention to the action of insects is due to the fact that the down prevents the limbs of insects from coming in contact with the surface of the material and gripping it so as to exert the force necessary for perforating it.

To this end, the coverage of the material by down must be total, preferably so that the coats overlap so that there is no space 0. between adjacent coats through which the tapering ends of insect 00 0 limbs could make contact with the supporting sheet.

00 0f 15 One possible embodiment of the invention is illustrated in the 00° following examples, which should not be regarded as in any way e0o limiting the scope of the invention, 0 S From the experimental viewpoint, note that paper by itself has very 9000 :20 little resistance to the perforating activity of insects, and 0o,° therefore more clearly shows the advantage of applying the down according to the Invention, 0 Examples 00 00 S0 1) Preparation of the packaging Packaging was prepared from the following starting materials: Supporting sheet: Paper made from recycled cellular fibre 100 pm thick and weighing 75 g/m 2 Adhesive: Acetovinyl adhesive;

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6 Down: 1.5 denier polyamlde fibre (diameter about 12 pim) and 0.6 mm high; the surface density of the applied fibre was between 55 and 75 g/m 2 materials were used to prepare a sheet which was then cut into strips of material 7 cm wide and 24 cm long.

Bags were made by folding the strips in two. and welding them on three sides, Some bags had down facing the exterior and some hnd down facing the S, 0interior.

to The bags were welded with tape adhesive on both sides and about 1 cm wide, and were reinforced with metal tacks. Three tacks were used on each long side and two on the short side for closing, Other bags of identical size were made in the same manner from the supporting sheet by itself, without down.

2) Tests of resistance to perforation About 20 g of "Superfino Arborlo" type rice were placed in all the bags manufactured as in Section 1).

The bags with down on the outside were intended for testing the resistance of the material according to the invention, whereas the paper bags without surface down were for use as controls, Finally, the bags made with down on the internal surface provided a control for imponderable factors such as any insect--repelling properties of the adhesive substance or the like, Tests were made on three species of insect noted for their very high perforation capacity and tendency to penetrate food packaging, as 7follows: Rhyzopertha dominica (Coleoptera, Bostrychldae); Tribolium confusum du Val (Coleoptera, Tenebrionidae); Ephestia kOhnlella (Zeller) (Lepidoptera, Phycitidae).

Each species was present in five vessels, each containing a single species.

The five vessels holding Tribolium confusum contained the following respectively at the beginning of the test: 201 adults and 208 larvae; 206 adults and 200 larvae; 200 adults and 199 larvael 201 adults and 200 larvae; 200 adults and 200 larvae. 100 g of wheat flour serving as a food subs'rate were placed in each vessel.

15 The five vessels containing Ephestia kUhniella each initially contained 16 larvae aged III and IV and 30 g of wheat flour was placed in each vessel.

I i 300 g of wheat and maize flour, mixed in equal parts and taken from S 20 Rhyzopertha dominica breeding establishments were placed in each of the five vessels holding Rhyzopertha dominlca. Since this substrate was massively infested, it was impossible to determine the number of insects In various stages of development present, but in any case there were hundreds of Individuals, Three bags manufactured as in Item 1) (one of each type) were placed vertically in each vessel.

The vessels were kept at 25'C and at 75 per cent relative humidity.

The photoperlod (ratio of light to darkness) was 14 The bags were checked weekly for about 4 months and monthly during the subsequent 8 months.

I p I I_ 8 3) Results The variation in perforations in bags subjected to activity of various insects is shown in the graphs reproduced in the accompanying drawings, in which: Fig. 1 is a graph in which the ordinpte shows the number, with respect to time, of bags of the aforementioned three different kinds, i.e, external down, internal down and without down, which were perforated by Rhyzopertha dominica; Fig, 2 is a graph in which the ordinate shows the number, with respect to time, of bags of the three different kinds described (with external down, with internal down and without down) perforated by Tribolium confu'sum; and Fig. 3 is a graph in which the ordinate shows the number, in dependence on time, of bags of the three different kinds described (external down, internal down and without down) perforated by Ephestia kUhniella, In the three drawings, the continuous line shows the increase in per'oration of bags with external down; the chain-dotted line shows the increase in the perforation of bags with down facing the interior, and the chain line shows the increase in perforation of bags of paper without down, The abscissae show the dates when the state of preservation of the bags was checked.

In the test with Tribolium confusum it was found that, three months after the beginning of the test, 8 of the control bags (paper or with internal down) had been perforated whereas only two bags with external down had a few minute cracks, presumably due to the mechanical thrust exerted by the rice in combination with moisture absorbed by the paper, .2 9 The test with Ephestia ktlhniele showed that five months after the beginning, all the paper bags were perforated whereas none of tle bags with external down were perforated, The first paper bag was perforated after seven days whereas the first bag with external down according to the invention was perforated afer six months, The test with Rhyzopertha dominica showed that after 15 days, all five paper bags had been perforated. After a month, the papers with internal down had also been perforated by insects, I V, The first bag with external down was perforated after 3 months, whereas it took a year before all five bags had been perforated.

Since the material according to the invention can be used for wrapping or containers suitable for prolonged preservation of goods and food Inserted therein, the supporting sheet must be able to withstand this period of storage without deterioration, The material used for this purpose can be either paper or cellophane or other materials compatible with the packed product and the storage conditions.

It has been found, however, that any packaging material, whether in sheet or other form, can be used as a support for down and as a result is made more resistant to attack by insects.

The down material is advantageously a synthetie flbra. Vegetable fibres such as cotton are unsuitable for the purpose since insects may attack and demolish them and thus uncover the supporting sheet, which will then be exposed unprotected to further attack by the insects.

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Polyamide resin fibre (commercially known as "Nylon") has been found suitable, since it Is not attacked by insects and it efficiently protects the supporting sheet, Although the description refers particularly to sheet material having a downy surface, it should be understood that the invention also covers any otihr embodiment comprising the idea of a structural obstacle presented by the surface of the packaging material against eating by insects, More particularly the invention should be regarded as including all coatings or surface treatments giving the packaging material Smicroscopic rough portions less than 50 pm in size and in the form of unevenness, scales, projections or the like and adapted to o 15 completely cover the supporting material, 4 9 a 0 0 0 o e

Claims

1. Food-product packaging resistant to eating by insects, characterised in that said packaging comprises a sheet packaging material compatible with the product to be packed or wrapped and with use thereof, the entire surface of the material having adhered thereto a down of synthetic material, inedible to insects, thereby providing a uniform distribution of rough portions, as hereinbefore defined, having dimensions substantially smaller than the size of an attacking insect.

2. Food-product packaging resistant to eating by insects according to claim 1, characterised in that the rough portions as herL-before defined have dimension substantially less than 50 ptm.

3. Food-product packaging resistant to eating by insects according to claim 1, characterised in that the down is made of spun synthetic fibre between 5 and 20 igm in diameter and having a length between 20 and 100 times the fibre diameter, bonded to the sheet of packaging material by an adhesive and having a sufficient density, relative to the size of fibre to completely cover the surface of the material. i Food-product packaging material resistant to eating by insects according to claim 3 characterised in that the down has a fibre density between 10 and 100 g/m2.

5. Food-product packaging resistant to eating by insects according to claim 1 characterised in that the sheet of packaging material is made of paper having mechar 'al characteristics adapted to the material for insertion into the packaging and to the size thereof. Sta 6, Food-product packaging resistant to eating by insects according to claim 1 characterised in that the sheet of packaging material is made of cellophane.

7. Food-product packaging resistant to eating by insects according to claim 1, characterised in that the down is made up of polyamide resin fibres.

8. Food-product packaging resistant to eating by insects according to claim 7, characterised in that the down is made up of 1.5 denier polyamide resin fibres (about 12 Itm in diameter) and 0.6 mm long, the density of fibres on the surface being between and 80 g/m 2 and the fibres being bonded to the sheet of packaging material by an acetovinyl adhesive.

9. Food-product packaging resistant to eating by insects according to claim 1, characterised in that the down of synthetic material is adhered to a surface of the sheet packaging material before packaging, so that the coated surface faces the exterior of the packaging. Food-product packaging resistant to eating by Insects according to claim 1, characterised in that the down of synthetic material is adhered to the outer surface of the sheet packaging material after packaging. DATED this 6th day of August 1992. CONSIGLIO NAZIONALE DELLE WATERMARK PATENT TRADEMARK ATTORNEYS THE ATRIUM i 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA i