Waste packing system and film

Abstract

The present invention is directed to a waste packaging system, a method of storing waste and to a film for use in this system and method.

Claims

1. A method for storing waste by using a device comprising (i) a dispensing apparatus where a plastic film of weight/surface ratio less than 20 grams per square meter is stored; (ii) a fusion seal apparatus comprising a battery with a maximum voltage of equal to or less than 20 V; and (iii) a bin where the fusion seal apparatus is located; the method comprising: a. pulling out the plastic film of weight/surface ratio less than 20 grams per square meter from the dispensing apparatus; b. putting a waste item in a suitable length of the plastic film; and c. closing hermetically the plastic film with the use of the fusion seal apparatus to provide a seal between a part of the plastic film and another part of the same plastic film, where the sealed parts are put sequentially in the bin.

2. A plastic film for use in the method according to claim 1, comprising at least an outer layer comprising at least 50% per weight polyethylene homopolymer and/or copolymer, where the weight/surface ratio of the plastic film is less than 20 grams per square meter and where the plastic film can be heat sealed with the thermal energy transferred with the battery with the voltage of equal to or less than 20 V.

3. The plastic film of claim 2, further comprising an internal layer comprising at least one oxygen barrier material and/or a sealing layer comprising at least 50% per weight polyethylene homopolymer and/or copolymer, wherein the sealing layer is a layer configured to be sealed using the fusion seal apparatus, and wherein the internal layer is a film layer located between other layers of the plastic film.

4. The plastic film of claim 2, comprising a sealing layer comprising at least 50% per weight polyethylene homopolymer and/or copolymer.

5. The plastic film of claim 2, where the weight/surface ratio is less than 15 g/m.sup.2.

6. The plastic film of claim 2, where the weight/surface ratio is less than 13 g/m.sup.2.

7. The plastic film of claim 2, comprising an internal layer comprising an oxygen barrier material, where the oxygen barrier material is EVOH, PVDC or polyamide.

8. The plastic film of claim 2, where the polyethylene copolymer is selected from the group consisting of a copolymer of ethylene and butene, a copolymer of ethylene and hexene, and a copolymer of ethylene and octene.

9. A plastic film for use in the method according to claim 1 comprising at least an outer layer comprising polyethylene homopolymer and/or copolymer; a sealing layer comprising polyethylene homopolymer and/or copolymer; and an internal layer located between the outer layer and the sealing layer, wherein said internal layer comprises at least one oxygen barrier material; where the weight/surface ratio of the plastic film is less than 20 grams per square meter and where the plastic film can be heat sealed with the thermal energy transferred with the battery with the voltage of equal to or less than 20 V.

10. The plastic film of claim 9, wherein the outer and/or sealing layer comprise at least 50% per weight polyethylene homopolymer and/or copolymer.

11. The plastic film of claim 9, where the weight/surface ratio is less than 15 g/m.sup.2.

12. The plastic film of claim 9, where the weight/surface ratio is less than 13 g/m.sup.2.

13. The plastic film of claim 9, where the oxygen barrier material is EVOH, PVDC or polyamide.

14. The plastic film of claim 9, where the polyethylene copolymer is selected from the group consisting of a copolymer of ethylene and butene, a copolymer of ethylene and hexene, and a copolymer of ethylene and octene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view of an embodiment of a presently disclosed apparatus.

(2) FIG. 2 is a perspective view of an embodiment of a presently disclosed apparatus.

(3) FIG. 3 is a side view of an embodiment of a presently disclosed apparatus.

DETAILED DESCRIPTION OF THE INVENTION

(4) The present invention is directed to a device comprising 1. a dispensing apparatus where a plastic film of weight/surface ration less than 20 grams per square meter is stored 2. a bin where a fusion seal apparatus is located 3. a fusion seal apparatus comprising a battery with a maximum voltage of 20V.

(5) The battery preferably is rechargeable.

(6) In some embodiments, the dispensing apparatus has the form of a cassette.

(7) In some embodiments, the voltage is less than 16 V. In some embodiments, the voltage is less than 12 V.

(8) In some embodiments, the temperature for a heat seal is set to less than 100 C., less than 90 C., or less than 80 C. In some embodiments, the sealing time is set to less than 5 seconds, less than 3 seconds, or less than 1 second.

(9) Another aspect of the present invention is a method of packing waste items by 1. pulling out plastic film of weight/surface ration less than 20 grams per square meter from a dispensing apparatus 2. putting a waste item in a suitable length of the film 3. closing hermetically the plastic film with the use of a fusion seal where the seal is between a part of the film and another part of the same or other film, where the sealed parts are put sequentially in a bin.

(10) The fusion seal is preferably done with a fusion seal apparatus comprising a battery with a maximum voltage of 20V.

(11) A still further aspect of the present invention is a method of packing waste items by 1. pulling out plastic film of weight/surface ration less than 20 grams per square meter from a dispensing apparatus 2. putting a waste item in a suitable length of the film 3. closing hermetically the plastic film with the use of a fusion seal where the seal is between a part of the film and another part of the same or other film where the film is able to be sealed through pleats and wrinkles, where the sealed parts are put sequentially in a bin.

(12) A preferred embodiment of the present invention is a method of packing waste items by 1. pulling out plastic film of weight/surface ration less than 15 grams per square meter from a dispensing apparatus 2. putting a waste item in a suitable length of the film 3. closing hermetically the plastic film with the use of a fusion seal where the seal is between a part of the film and another part of the same or other film where the film is able to be sealed through pleats and wrinkles,
where the sealed parts are put sequentially in a bin.

(13) Also another object of the present invention is a plastic film comprising at least a layer comprising at least 50% per weight of polyethylene homopolymer or copolymer, where the weight/surface ratio is less than 20 grams per square meter and the film can be heat sealed with the thermal energy transferred with a battery with a voltage of less than 20 V.

(14) Also another object of the present invention is a multilayer plastic film comprising at least 1. an outer layer comprising polyethylene homopolymer and/or copolymer 2. an internal layer comprising at least one oxygen barrier material 3. an inner layer comprising polyethylene homopolymer and/or copolymer,
where the weight/surface ratio is less than 20 grams per square meter and the film can be heat sealed with the thermal energy transferred with a battery with a voltage of less than 20 V.

(15) In a preferred embodiment, one or both of the outer and inner layers comprise at least 50% per weight of polyethylene homopolymer and/or copolymer.

(16) Dispensing Apparatus

(17) A dispensing apparatus of the present invention preferably has the form of a cassette. Nevertheless, other dispensing apparatus are also possible in which a cassette is not used. For example the film can be wound in the form of a mini roll around a paper core. Alternatively, two such mini rolls may comprise the film in such a way that the film wound in the first mini roll will heat seal to the film that is wound in the second mini roll.

(18) Cassette

(19) In a preferred embodiment the cassette useful for the invention is circular in shape (see FIG. 1). Preferably it is made by plastic, eg polypropylene.

(20) It is also possible to be manufactured from other means more friendly to the environment such as paper, biodegradable plastic or non biodegradable plastic where a percentage of degrading additives have been added.

(21) Generally, the cassette comprises a tubular core (see reference number 14 in FIG. 1), casing wall (see reference number 12 in FIG. 1), cassette bottom and lid (see reference number 13 in FIG. 1). The film is stored in an area between tubular core, casing wall and cassette bottom in a compressed configuration. The flexible tubing is dispensed from the cassette.

(22) In a further preferred embodiment of the invention the cassette comprises a malodor counteractant useful for absorbing, adsorbing or masking the smell of the waste.

(23) In a preferred embodiment of the invention the film inside the cassette the film is in compressed configuration.

(24) Seal Apparatus

(25) A preferred version of the sealing apparatus of the present invention is an apparatus capable of impulse sealing. An impulse sealer is a jaw sealer backed with resilient silicone rubber. Electric current flows through Nichrome ribbon stretched over one over one or both surfaces and covered with high temperature release film and fabric.

(26) Another preferred version of the seal apparatus is wire or knife sealing. According to this method a hot wire or knife seals and cuts the film.

(27) Other methods for the seal apparatus that could be used according to the invention include bar sealing, band sealing, ultrasonic sealing, friction sealing, gas sealing, contact sealing, hot melt sealing, pneumatic sealing, dielectric sealing, magnetic sealing, induction sealing, radiant sealing, solvent sealing etc. For these methods please refer to the Wiley Encyclopedia of packaging technology, edition 1997.

(28) In a preferred embodiment of the invention the electric current necessary for the heat sealing and fusion is provided through a rechargeable battery. The voltage of the rechargeable battery is preferably equal or less than 20 V, even more preferably less than 16 V, even more preferably less than 12V.

(29) In a preferred version of the invention the temperature for the heat seal is less than 100 C., preferably less than 90 C., preferably less than 80 C.

(30) In a further preferred version of the invention, the sealing time is less than 5 seconds, more preferably less than 3 seconds, more preferably less than 1 second.

(31) In a further preferred version of the invention, the cutting of each pack to the previous one is done simultaneously with the sealing by the use of a wire/knife configuration. In another version, there is no cutting. In this case all the packs are put together inside the bin in a single line.

(32) The use of a rechargeable battery of low voltage assures a safe procedure that is more user friendly than household electricity.

(33) Another alternative possibility of the invention is the use of more than one heat seal to make an individual pack. So two, three or four seals are possible.

(34) In the case of three or four seals, the film should be in a single sheet configuration instead of flexible tubing.

(35) In FIG. 2 there is further explanation of the sealing apparatus. The two sealing jaws (see reference number 23) are heat sealing the flexible tubular film. The sealing jaws are movable on a railway (see reference number 22) and the movement is controlled through as gear reducer (see reference number 21). This is also displayed in FIG. 3 from another view.

(36) The activation of the sealing mechanism can be done by the person using the apparatus preferably by pushing an activation mechanism (eg a button or a lever) either by hand or by foot. The activation mechanism provokes by preferably mechanical or pneumatic transmission system the movement of the sealing jaws therefore allowing the fusion seal to occur. Electrical transmission is also possible by using a battery as a source of power.

(37) Film Characteristics

(38) The basic characteristics a film should have in order to be used in the particular case are 1. Barrier to odours 2. To have the proper deadfold properties (non resilient) so that is compressed efficiently in the cassette if a cassette is used as a dispensing apparatus. 3. To have sufficient mechanical properties (eg tensile strength at break, elongation). 4. To have sufficient sealing properties as to be sealed with a low voltage rechargeable battery. Also the sealing properties must be sufficient to seal through wrinkles or pleats that are inevitable for this kind of application.

(39) We have surprisingly found that all these features can be achieved with a very lightweight multilayer film with weight per surface ratio less than 20 grams per square meter, preferably less than 18 grams per square meter. This is extremely beneficial for the environment as multilayer films are extremely difficult to be produced with so small weight per surface.

(40) In order for a film to be able to heat seal hermetically to itself or to other film with the power generated by a low voltage battery and also be able to keep the other critical characteristics (odour barrier, sealability through pleats and wrinkles, mechanical strength) it should combine the following characteristics: 1. Comprise an internal layer comprising at least one oxygen barrier material 2. Comprise one outer layer comprising more than 50% per weight polyethylene homopolymer and/or copolymer and one inner layer comprising more than 50% per weight polyethylene homopolymer and/or copolymer 3. Have a weight/surface ratio of less than 20 grams per square meter. 4. The film can be heat sealed with the thermal energy transferred with a battery with a voltage of equal or less than 20 V.

(41) According to a further aspect the present invention is directed to a multilayer film with weight less than 15 g/m.sup.2 which: 1. Comprises a layer comprising at least one oxygen barrier material 2. Comprise one outer layer comprising more than 50% per weight polyethylene homopolymer and/or copolymer and one inner layer comprising more than 50% per weight polyethylene homopolymer or copolymer 3. The film can be heat sealed with the thermal energy transferred with a battery with a voltage of equal or less than 20 V.

(42) According to a further aspect the present invention is directed to a multilayer film with weight less than 13 g/m.sup.2 which: 1. comprises a high oxygen barrier layer comprising at least one oxygen barrier material 2. comprise two outer layers comprising more than 50% per weight polyethylene homopolymer or copolymer 3. the film can be heat sealed with the thermal energy transferred with a battery with a voltage of equal or less than 20 V.

(43) In a further preferred embodiment, the film comprises the construction:

(44) Outer Layer/Abuse Layer/Intermediate Layer/Barrier Layer/Intermediate Layer/Abuse Layer/Inner Layer

(45) In another preferred embodiment, the film comprises the construction

(46) Outer Layer/Intermediate Layer/Barrier Layer/Intermediate Layer/Inner Layer

(47) Detailed Description of Layers:

(48) Barrier (Internal) Layer

(49) In a preferred version of the invention, the oxygen barrier material in the barrier (internal) layer is EVOH, PVDC or polyamide. The EVOH used preferably has an ethylene content less than 48%, more preferably less than 44%, more preferably less than 38%, more preferably from 27 to 32% ethylene.

(50) The oxygen barrier material preferably has a weight of less than 3 g/m.sup.2, more preferably less than 2 g/m.sup.2 and even more preferably less than 1.5 g/m.sup.2.

(51) Outer Layer

(52) In a preferred version, the outer layer comprises at least 50% per weight polyethylene homopolymer or copolymer.

(53) In a further preferred version, the weight of the outer layer is less than 6 g/m.sup.2, more preferably less than 5 g/m.sup.2.

(54) In a further preferred version, the polyethylene is a copolymer or a blend of different monomers or polymeric structures. This blending may take place during polymerization or as a later stage.

(55) In a further preferred version the polyethylene is a copolymer of ethylene and butene or a copolymer of ethylene and hexene or a copolymer of ethylene and octene.

(56) In a further preferred version the polyethylene has a density of between 0.885 and 0.960 g/m.sup.3, more preferably 0.910 to 0.940 g/m.sup.3.

(57) Inner Layer

(58) Preferred materials for the inner layer include polyethylene homopolymer or copolymers, such as low density polyethylene, high density polyethylene, ethylene ester copolymer, ethylene alpha olefin copolymer and ethylene propylene copolymers. Ethylene based ionomers and ethylene styrene copolymers are also possible. Ethylene alpha olefin copolymer is particularly preferred.

(59) According to a further embodiment, the present invention is of the same configuration where the inner layer comprises a substantially non resilient material (SNR).

(60) In a preferred version of the invention, the SNR material is at least 10 percent, preferably at least 20, preferably at least 30 percent per weight of the inner layer.

(61) Intermediate Layer

(62) In the intermediate layers, typical adhesive resins like maleic anhydrite modified polyolefins may be used. Typical examples are BYNEL from Dupont and OREVAC from Arkema.

(63) In another preferred version of the invention, polyamide could be used as intermediate layer.

(64) Abuse Layer

(65) In a multilayer configuration where abuse layers are also present, these layers may comprise polyethylene and polypropylene homopolymers or copolymers. Polyamides are also possible.

(66) General

(67) Additives well known in the art may be used in one or more layers of the present invention. Slip additives, antiblock additives, antifog, polymer processing aids may be used if pertinent. Antimicrobial additives may also be used in one or more of the layers to inhibit the microbe formation. Preferably the antimicrobial is put on the side where the waste is in direct vicinity.

(68) In order to increase the mechanical properties the film may be crosslinked with one of the following methods.

(69) E-beam radiation, gamma radiation, moisture crosslinking using silane grafting compounds, peroxide crosslinking.

(70) The film may be in tubular form or sealed at the edges or single sheet configuration. Centrefold configuration is also possible.

(71) The preferred production method for the film is the hot blown film method, which is well known in the art. Other methods like extrusion through flat cast die is also possible. The hot blown film method allows orientation of the plastic from the melt state. Biaxiallly oriented film such as those produced by double bubble or tenter frame method are not really efficient for the application during the much higher complexity of the process which renders the production cost much higher.

(72) As outlined above, the inner and outer layers of the present invention are substantially free of cling additives meaning additives that allow the layer adhere to itself by pressing force without the need of fusion seal. Addition of such additives is costly and complicated. Also it makes the whole process much less friendly due to the tacky nature of the cling additive.

EXAMPLES

(73) A 5 layer film is produced in a commercial hot blown film line with the following recipe

(74) Inner layer, 80% EAO1+15% SNR1+5% ADDITIVES

(75) Adjacent layer 100% ADH 1

(76) Barrier layer EVOH 1

(77) Adjacent layer 100% ADH1

(78) Outer layer 100% EAO1

(79) See table 1

(80) The thickness of the structure is 4/1.5/1.5/1.5/4 starting from the inner and going to the outer layer. The weight of the film is 12.145 g/m.sup.2.

(81) TABLE-US-00001 TABLE 1 Density Type Description g/cm.sup.3 EAO1 Ethylene octene 0.92 copolymer SNR1 Calcium 1.6 carbonate compound AD1 LLDPE mod. 0.92 Adhesive tie EVOH 1 EVOH with 32% 1.19 ethylene EVOH 2 EVOH with 29% 1.2 ethylene

Example 2

(82) A 5 layer film is produced in a hot blown film commercial line with the following recipe

(83) Inner layer, 80% EAO1+15% SNR1+5% ADDITIVES

(84) Adjacent layer 100% ADH 1

(85) Barrier layer EVOH 2

(86) Adjacent layer 100% ADH1

(87) Outer layer 80% EAO1+15% SNR1+5% ADDITIVES

(88) The thickness of the structure is 5/1.5/1.5/1.5/3 starting from the inner and going to the outer layer.

(89) The weight of the material is 12.385 g/m.sup.2.

Example 3

(90) A 5 layer film is produced in a hot blown film commercial line with the following recipe

(91) Inner layer, 80% EAO1+15% SNR1+5% ADDITIVES

(92) Adjacent layer 100% ADH 1

(93) Barrier layer EVOH 2

(94) Adjacent layer 100% ADH1

(95) Outer layer 80% EAO1+15% SNR1+5% ADDITIVES

(96) The thickness of the structure is 5/3/1.5/3/5 starting from the inner and going to the outer.

(97) The weight of the material is 17.1 g/m.sup.2.

(98) Tests

(99) 1. Tensile strength and elongation test is done according to ASTM D 882. 2. Odour test is done in the way described below.
Test 1.

(100) Tensile strength and elongation is measured as per ASTM D882.

(101) MD stands for machine direction, whereas TD stands for transverse direction.

(102) TABLE-US-00002 TENSILE ELONGA- TENSILE ELONGA- STRENGTH TION STRENGTH TION EXAMPLE (MD) (MD) (TD) (TD) 1 22 250 21 630 2 21 225 19.8 550 3 25 190 23 520
Odour Testing

(103) 10 soiled diapers are put in a film of the present invention and also in a commercially sold film. The commercially sold film is believed to be monolayer.

(104) The packs are put in PVDC comprising bags, so the odour cannot escape during the time of the evaluation.

(105) The bags are opened 3 days after the soiling of the diapers and smell was evaluated by a 5 member panel.

(106) The packs made from examples 1 and 2 were found substantially less smelly than the commercially sold ones.

(107) Sealing Testing

(108) The sealing testing was done in comparison with a commercial film specialized for the particular application with a weight/surface ratio of 21.9 g/m.sup.2. For the testing two sealing jaws that used the energy produced by a battery of 20 V were used.

(109) It was surprisingly found that the film of examples 1, 2 and 3 were able to seal efficiently even through wrinkles with the sealing apparatus. On the other hand, the film of 21.9 g/m.sup.2 was not able to seal efficiently. If the sealing time was increased (something which is not desirable according to the invention) the seal was burned.