AU739085B2 - Wrapping materials - Google Patents

Description

-KU11 H J I-HKK U U 061262H53929 P.04/16

-I-

Regulation 3.2

AUSTRALIA

PATENTS ACT, 1990 COMPLETE

SPECIFICATION

FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Actual Inventor: Address for Service in Australia: Invention Title: AEP INDUSTRIES (NZ) LIMITED, a duly incorporated company of New Zealand of 100 Carbine Road, Mt Wellington, Auckland, New Zealand Lawrence Joseph Olsen, a New Zealand citizen of 5 Puna Street, Orakei, Auckland, New Zealand and Gregory Lloyd Stevenson, a New Zealand citizen of 47 Oregon Place, West Haven, Christchurch, New Zealand A J PARK SON, Level 11, 60 Marcus Clarke Street, Canberra ACT 2601 "Wrapping Materials" The following statement is a full description of this invention, including the best method of peyforming it known to ?ne./us P392692 AHB/emp -2- The present invention to a wrapping material. As used herein the term "wrapping material" relates preferably to flexible material capable of being used as a wrap, e.g. of butter. The term "wrapping material" however does not mean that the material must necessarily be used as a "wrap" in a strict sense, provided it is used as a packaging material preferably having the ability to satisfy food grade requirements such as they currently exist.

Traditionally butter is packaged in a wrap of a laminate of a metal foil adhered to parchment, the parchment being the butter contacting surface. The metal foil is primed, printed and embossed to provide an aesthetic outer visible surface for traditional the block of butter. Several prior art patent specifications have discussed the simulation of the traditional laminated wrapping wherein a coated paper board is provided with a foil like appearance. Such an appearance is capable of being achieved by printing a metalised ink onto a paper board. The difficulty in achieving a foil like look by the printing of a metalised ink onto paper is being able to achieve a desirably high luster to simulate or emulate existing metal foil wrap types, as the natural .i absorbance of a metalised ink into paper when it is applied, decreases the luster of the S•metalised ink coating. This problem has been discussed in US4568574 which discloses the application of a highly pigmented white ink to the paper, over which a non leafing "metalised ink may be applied to achieve a foil like appearance.

'20 In US4363851 there is disclosed the application of a barrier layer to a paper substrate for preventing the migration of contaminating substances in the paper substrate to the paper substrate surface opposite to the deposited layer. The application of the metal deposited layer onto the paper substrate is achieved by a vacuum deposition. The barrier coat as found by the inventors ofUS4363851 is of particular advantage so as to avoid contaminating substances contained in the paper impairing the surface characteristics of the metalised layer when the sheet material is in a rolled or stacked condition.

In US4434259 there is described the use of an improved base coating for use on paper to be vacuum metalised. The application of base coating achieves to some extent the filing of minor surface imperfections and hence provides a smooth surface to receive the metal deposit and hence provides a metalised surface which is higher in luster than if the deposited metal was applied direct to the paper. A lacquer containing a vinyl acetate/acrylic acid co polymer and nitrocellulose is disclosed as a base coating for a clay coated paper substrate.

-3- The present invention is directed to an alternative to such a wrapping material but to an alternative that nevertheless can preferably be used to provide some form of simulation or emulation of such existing wrap types.

In still another aspect it is object of the present invention to provide as an option a wrapping material providing an effective barrier without reliance on a metal foil.

In a first aspect the present invention consists in a wrapping material comprising or including a cellulosic fibrous material substrate, a coating on one side of said substrate, and a continuous or discontinuous printed surface on (whether on all or part of) said coating wherein said coating has been applied in the form of a fluid comprising or including a resin or a resin including system, and "5 wherein said printed surface has been applied in the form of a low particle aluminium paste or a low particle aluminium paste based ink.

Preferably said substrate is parchment.

.o ~Preferably said substrate is of a single layer.

Preferably said coating in its pre-applied fluid form consists of a composition based on an alcohol soluble nitrocellulose blended with a low molecular weight high acid value acrylic resin and SAIB.

Preferably said composition of said coating is a composition pigmented with calcium carbonate.

Preferably said wrapping material is embossed.

Preferably said substrate also carries a coloured printed region(s) applied directly said coating material and/or said printed surface(s).

Preferably said coating has been applied flexographically to said substrate.

Preferably said printed surface has been applied to said coating using inline or out of line flexography or gravure printing processes.

Preferably said coating is applied to said substrate at a thickness to prevent (at least any substantial) migration of aluminium particles of said printed surface therethrough.

Preferably said coating is applied substantially between 0.5 to 2 gsm (dry).

Preferably said coating is about 1 gsm dry.

Preferably said printed surface contains a low particle aluminium paste known as STAPA t paste of Eckart Werke of Germany.

-4- Preferably said STAPA T M Eckart Werke aluminium paste is blended with Eckart Werke aluminium pigment (AAluminium 500-001").

Preferably said printed surface is in its pre-applied condition includes a blend in a weight ratio of approximately 4:1 of Aluminium 500-001 pigment and STAPA T M Alternatively an orange pigment may be added to simulate a gold like appearance.

In a second aspect the present invention consists in a method of forming a paper/metal foil laminate simulating wrapping material, said method comprising the steps of: providing a cellulosic fibrous material substrate, applying a barrier coating of a resin or a resin including system to one major surface of said cellulosic fibrous material substrate, l *.*-printing onto selected or the entire areas of said barrier coating a layer comprising of a low particle aluminium paste or a low particle aluminium paste based 15 ink.

Preferably said method further includes the optional printing of coloured region over (whether directly on or with an interposing layer(s)) said barrier coating and/or said printed layer (whether directly on or with an interposing layer(s)).

Preferably said barrier coating is provided on only those regions of said substrate where said printed layer and said optional coloured regions are to be provided.

Alternatively said barrier coating is provided on the entire surface of said substrate, irrespective of whether or not region(s) of said printed layer and/or coloured regions are to be provided thereon.

Preferably said coloured regions are provided over all regions of said barrier coating save for those region where said metalised ink are printed.

Alternatively said coloured regions are provided on or also on at least part of said printed layer region(s).

Preferably said applying of said barrier coating is by printing.

Preferably said printing of said barrier coating is achieved flexographically.

Preferably said cellulosic fibrous material substrate is paper or parchment of between 45gsm and Preferably said printing of said printed layer is on the entire surface of said barrier coating.

Preferably said printed layer is applied to said coating using inline or out of line flexography or gravure printing processes.

Preferably said coating is applied at a weight between 0.5 to 2 gsm (dry) Preferably said coating applied at about 1 gsm dry.

Preferably said printed layer contains in its pre-applied condition includes a low particle aluminium paste known as STAPAt paste of Eckart Werke of Germany.

Preferably said Stapa Eckart Werke aluminium paste is blended with Eckart Werke aluminium pigment (Aluminium 500-001").

Preferably said printed layer is in its pre-applied condition material includes a blend in a weight ratio of approximately 4:1 of Aluminium 500-001 pigment and

STAPA.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

The invention consists in the foregoing and also envisages constructions of which S- the following gives examples.

One preferred form of the present invention will now be described with reference to the accompanying drawings in which; 20 Figures 1A to 1D are cross sectional views of wrapping materials in accordance with the present invention, Figure 2 shows process steps leading to a wrapping material in accordance with the S.present invention.

In the preferred form of the present invention the wrapping material is for wrapping butter with a bare parchment surface being the wrap surface which is to contact the butter.

Figures 1A through 1D show a number of different options.

Figure 1A shows a simplified form of the present invention where there is a substrate of a single layer of a suitable parchment 1. A suitable parchment is that of

SULPAC

TM by manufacturer ELSTROM having a weight grade range of from 45gsm to The coating 2 is preferably a resin base system of preferably a pigmented (preferably with calcium carbonate) composition based on an alcohol soluble nitrocellulose blended with a low molecular weight high acid value acrylic resin and sucrose acetate iso buterate ("SAIB").

Preferably said coating is applied flexographically to provide a coating weight of about 1 gsm dry. The coating 2 once dry can then be overprinted with a print layer 3 that -6can be applied using inline or out of line flexography or gravure printing procedures. A suitable composition of printed layer 3 simulating the metal foil is a blend of preferably about 4:1 of Aluminium 500-001 and STAPAT.

Figure 1B shows an alternative procedure to that of Figure 1 where the layer 3 differs from that of Figure 1A in that it is discontinuous as opposed to continuous.

Figure 1C is yet another alternative and likely the most preferred format, namely one where a discontinuous printed layer 3 (which simulates a metal foil) may be associated with other printed regions (preferably to the same thickness or depth but not necessarily so) and preferably without overprinting. The preferred printing methods as herein described allow for such selective are printing to be achieved. For example Figure 1C allows coloured regions with any suitably and optional printing medium 4 (whether simulating a metallic surface or not) to be interposed with those 3 which simulate a metal foil. The sequence of such printing steps is not critical. Layer 3 may be applied before ii layer 4, or visa versa and whether overlapping or not.

Figure 1D shows yet a further embodiment where, instead of the arrangement whereby the printed regions 3 are discontinuous, the regions 3 are continuous but are overprinted with optional coloured printing 4. It should be appreciated that if desired, the layer 3 in the embodiment of Figure 1D could instead be the printed medium of 4 and that "in turn is overprinted in a discontinuous manner with the metal foil simulating ink as 20 aforesaid.

A preferred product as depicted in, for example, in Figures 1C or 1D has the following materials utilised to the following specification: Layer 1 parchment of between 50-60gsm Layer 2 coating of between .05-2.5 gsm dry and preferably 2gsm dry Layer 3 foil simulating printing of preferably lgsm dry Layer 4 (optional) colour printing of preferably 1.Sgsm dry it is envisaged that these densities can vary by Figure 2 shows a procedure whereby a product as depicted in, for example, Figures 1 C or 1D can be provided.

The method of the present invention includes the provision of a cellulosic fibrous material such as parchment provided as a substrate. The substrate is then coated on a major surface of said substrate. This coating may be provided on the entire surface of the substrate or it may be pattern applied. So long as the coating is provided in regions where the subsequent layer 3 (and optional layer 4) is to be provided. After coating the coating layer is cured which is preferably accelerated by for example the use of convection heat/airflow drying. There then follows a printing steps of applying layer 3 and optionally layer 4. Such -7steps need not be restricted to two and may include appropriate indexing or overprinting of the layers subsequent to layer 2. Shown in Figure 2 is an optional embossing step which can be utilised at the end or indeed at some earlier stage in the processing. For example, embossing may be interposed between printing steps where there is printing of, for example, material 4 to be applied to the embossed region only.

Wrapping materials of the present invention provides an effective seal as a result of coating layer 2 for the low metallic inclusions to allow butter or other product to be wrapped therewith. Butter can contact the exposed parchment surface 1 yet all metal materials or other harmful contaminants contained in the layer(s) other than the coating layer are precluded from an easy passage through the coating 2 into the parchment and from thence to the food to be wrapped. The low metallic inclusion will not prevent the use of inline metal detection equipment to pick up metallic contamination of the food wrapped with the material.

As an example of a preferred composition the coating layer is applied in a form consisting of .SAIB at substantially 19.80% by weight (but may be between 15-20%) S" CaCO3 at substantially 19.25% by weight (but may be between 15-20%) Nitro cellulose at substantially 10.45% by weight (but may be between 8-12%) Cyclic ketone substantially 4.00% by weight (but may be between Acrylic resin at substantially 4.00% by weight (but may be between such as a hydroxy functional acrylic resin a REACTOL tm 180 of Lawter International Inc.

the remainder being a solvent such as a suitable blend of alcohol and ester ""An alternative to the calcium carbonate pigment would be any other substantially transparent filler material such as china clay, talc or barium sulphate.

As an example the preferred composition of the foil simulating printed coating may include Aluminium at substantially 15% by weight (but may be between 13-17%) Polyvinyl buterate at substantially 6% by weight (but may be between 4-8%) Cyclic ketone at substantially 10% by weight (but may be between 8-12%) and the remainder being a suitable carrier such as a mixture of ethyl alcohol and propyl acetate containing preferably not less than 10% acetate and no more than 80% alcohol.

The ability of the compositions of the present invention to be applied to the substrate by printing process allow the for selective area printing of the compositions and hence a reduction in material quantities.

Claims (24)

1. A wrapping material comprising or including a cellulosic fibrous material substrate, a coating on one side of said substrate, and a continuous or discontinuous printed surface on (whether on all or part of) said coating wherein said coating has been applied in the form of a fluid comprising or including a resin or a resin including system, and wherein said printed surface has been applied in the form of a low particle aluminium paste or a low particle aluminium paste based ink.

2. A wrapping material as claimed in claim 1 wherein said substrate is parchment.

3. A wrapping material as claimed in claims 1 or 2 wherein said substrate is of a single layer.

4. A wrapping material as claimed in anyone of claims 1 to 3 wherein said .1 coating in its pre-applied fluid form consists of a composition based on an alcohol 4. 0: S" soluble nitrocellulose blended with a low molecular weight high acid value acrylic resin and SAIB.

5. A wrapping material as claimed in anyone of claims 1 to 4 wherein said composition of said coating is a composition pigmented with calcium carbonate.

6. A wrapping material as claimed in anyone of claims 1 to 5 wherein said wrapping material is embossed.

7. A wrapping material as claimed in anyone of claims 1 to 6 wherein said substrate also carries a coloured printed region(s) applied directly said coating material and/or said printed surface(s).

8. A wrapping material as claimed in anyone of claims 1 to 7 wherein said coating has been applied flexographically to said substrate.

9. A wrapping material as claimed in anyone of claims 1 to 8 wherein said printed surface has been applied to said coating using inline or out of line flexography or gravure printing processes.

10. A wrapping material as claimed in anyone of claims 1 to 9 wherein said coating is applied to said substrate at a thickness to prevent (at least any substantial) migration of aluminium particles of said printed surface therethrough.

11. A wrapping material as claimed in anyone of claims 1 to 10 wherein said coating is applied substantially between 0.5 to 2 gsm (dry). _i2. A wrapping material as claimed in anyone of claims 1 to 11 wherein said poating is about 1 gsm dry. -9-

13. A wrapping material as claimed in anyone of claims 1 to 12 wherein said printed surface contains a low particle aluminium paste known as STAPA T M paste of Eckart Werke of Germany.

14. A wrapping material as claimed in anyone of claims 1 to 13 wherein said STAPATM Eckart Werke aluminium paste is blended with Eckart Werke aluminium pigment (AAluminium 500-001"). A wrapping material as claimed in anyone of claims 1 to 14 wherein said printed surface is in its pre-applied condition includes a blend in a weight ratio of approximately 4:1 of Aluminium 500-001 pigment and STAPA T M

16. A method of forming a paper/metal foil laminate simulating wrapping material, said method comprising the steps of: providing a cellulosic fibrous material substrate, applying a barrier coating of a resin or a resin including system to one major surface of said cellulosic fibrous material substrate, printing onto selected or the entire areas of said barrier coating a layer comprising of a low particle aluminium paste or a low particle aluminium paste based ink.

17. A method as claimed in claim 16 wherein in said method further includes the optional printing of coloured region over (whether directly on or with an interposing layer(s)) said barrier coating and/or said printed layer (whether directly on or with an interposing layer(s)).

18. A method as claimed in claim 16 or 17 wherein said barrier coating is provided on only those regions of said substrate where said printed layer and said optional coloured regions are to be provided.

19. A method as claimed in claim 16 or 17 wherein said barrier coating is provided on the entire surface of said substrate, irrespective of whether or not region(s) of said printed layer and/or coloured regions are to be provided thereon. A method as claimed in any one of claims 16 to 19 wherein said coloured regions are provided over all regions of said barrier coating save for those region where said metalised ink are printed.

21. A method as claimed in any one of claims 16 to 19 wherein said coloured regions are provided on or also on at least part of said printed layer region(s).

22. A method as claimed in any one of claims 16 to 21 wherein said applying of said barrier coating is by printing. A method as claimed in any one of claims 16 to 22 wherein said printing of said er coating is achieved flexographically.

24. A method as claimed in any one of claims 16 to 23 wherein said cellulosic fibrous material substrate is paper or parchment of between 45gsm and A method as claimed in any one of claims 16 to 24 wherein said printing of said printed layer is on the entire surface of said barrier coating.

26. A method as claimed in any one of claims 16 to 25 wherein said printed layer is applied to said coating using inline or out of line flexography or gravure printing processes.

27. A method as claimed in any one of claims 16 to 26 wherein said coating is applied at a weight between 0.5 to 2 gsm (dry)

28. A method as claimed in any one of claims 16 to 27 wherein said coating applied at about 1 gsm dry.

29. A method as claimed in any one of claims 16 to 28 wherein said printed layer contains in its pre-applied condition includes a low particle aluminium paste known as STAPA" paste of Eckart Werke of Germany. Preferably said Stapa Eckart 1 Werke aluminium paste is blended with Eckart Werke aluminium pigment (Aluminium 500-001"). A method as claimed in any one of claims 16 to 29 wherein said printed layer is in its pre-applied condition material includes a blend in a weight ratio of :.approximately 4:1 of Aluminium 500-001 pigment and STAPA. Dated this 27th day of May 1999 By the authorised agents