GB2618057A

GB2618057A - Repulpable, self-adhesive printable paper

Info

Publication number: GB2618057A
Application number: GB2202603.3A
Authority: GB
Inventors: Gartshore Andrew
Original assignee: Gardiner Graphics Group Ltd
Current assignee: Gardiner Graphics Group Ltd
Priority date: 2022-02-25
Filing date: 2022-02-25
Publication date: 2023-11-01
Also published as: GB202202603D0

Abstract

A printable paper product having a central layer of a repulpable paper or card sheet, a repulpable printable lacquer coating on at least one side and a coating on the other side which may be a repulpable pressure sensitive adhesive. A release layer made of silicone coated glassine paper may cover the adhesive. The lacquer may be a polyacrylate based material. The paper may be wood free and have specific gsm weights. Also disclosed is a method of production. The product can be used use on outside advertising hoardings, as well as general inside and outside use on signage, advertising and labelling. It is fully repulpable and/or recyclable. The lacquer layer provides a degree of weatherproof that if sufficient for maintaining usefulness of the product.

Description

Repulpable, Self-Adhesive Printable Paper

Introduction

The invention relates to printable, self-adhesive, moisture stable, repulpable paper product, specifically although not exclusively for use in wide formal signs and the graphics industry, typically for advertisement and marketing.

Background to the Invention

Instore and exterior printable media is typically made from materials that are plastic based or include a plastic coating and/or backing. Consequently, they are not recyclable. Such displays or signage campaigns are often used for a period of 1-3 months before being replaced. This high turnover creates a large amount of waste that cannot be recycled.

There is therefore a need for a fully repulpable product that can be used for such signage, enabling the signed to be recycled.

It is also important that the product can be a printable label stock "narrow web" for use as labels and can be printed using flexographic, gravure, letterpress and digitally printable for maximum flexibility.

Such a product also needs to be self-adhesive so that it can be adhered for use, and that the adhesive is also repulpable for integration into the repulping process without any further actions being required to treat or remove the adhesive before repulping.

The object of the present invention is therefore to provide a fully repulpable paper product that is moisture stable for outdoor durability, printable and optionally includes self-adhesive.

Summary of the Invention

According to the invention there is provided a printable paper product comprising:-a sheet of repulpable paper or card; one or both sides of the sheet being coated with a repulpable printable lacquer; and none, one or both sides of the sheet being coated with a repulpable pressure sensitive adhesive; wherein each side of the sheet has at least one coating.

Thus, the invention provides a sheet of repulpable paper or card coated on at least one side with a repulpable printable lacquer, and optionally one or more sides having a coating of repulpable pressure sensitive adhesive.

Preferably, if a side of the repulpable paper or card is not coating with a repulpable lacquer it is coated with a repulpable pressure sensitive adhesive. Most commonly the sheet of paper or card is coated on both sides with a repulpable printable lacquer, and one side is coated with a repulpable pressure sensitive adhesive.

Preferably at least one side of the paper has an outer coating of a repulpable pressure sensitive adhesive.

Prior to use the product may typically include a release liner over the or each pressure sensitive adhesive (PSA) coating.

Preferably the repulpable printable lacquer may be a polyacrylate based material having a weight of between 5 gsm and 15 gsm.

Typically, the repulpable paper or card may be white or cream in colour and is usually wood free. Preferably the paper will have a weight of between 20 gsm and 1000 gsm.

Advantageously the repulpable PSA may be polyacrylate based and may be permanent or removable.

Where a release liner is provided, typically this will be a silicone coated glassine paper.

Alternatively, the release liner can be a recyclable material. In a further alternative, the release liner can be a double-sided polyethylene coated paper sheet, one side of which is silicone coated.

According to a second aspect of the invention there is provided a method of manufacturing a printable paper product, the method comprising:- (I) providing a sheet of repulpable paper or card; (ii) applying a coating of a repulpable printable lacquer over one or both sides of the repulpable paper or card sheet; (iii) applying a coating of a repulpable pressure sensitive adhesive over none, one or both sides of the repulpable paper or card sheet, wherein each side of the sheet has at least one coating.

Typically the method also comprises the step of applying a release layer over any coating of pressure sensitive adhesive.

Steps (ii) and (iii) (if provided) can be completed in any order, provided that no coating of replupable printable lacquer is over a coating of repulpable pressure adhesive.

In some embodiments a sheet of repulpable paper may be coated with the repulpable lacquer on one or both sides, and then in a second pass through a coating machine, coated on one or both sides with the repulpable pressure sensitive adhesive, which is then covered by a release paper.

Alternatively, the sheet of repulpable paper or card can be coated with the layer of repulpable pressure sensitive adhesive, which is then covered by a release layer, and then in a second pass through a coating machine, coated on the other side with a layer of repulpable lacquer.

Preferably, the method includes providing at least one side of the sheet with an outer coating of a pressure sensitive adhesive.

Once the sheet has been prepared, it can be cut into shorter or narrower lengths and widths for further use. This will typically be done on a slitting machine.

Final uses of the product may be die cuttable labels, including coloured and plain, pricing labels, bar code labels, OR code labels, picture or diagram printed labels, wide format printed graphics for sign and display industry use.

Where a release liner is provided, typically this will be a silicone coated glassine paper. Alternatively, the release liner can be a recyclable material. In a further alternative, the release liner can be a double-sided polyethylene coated paper sheet, one side of which is silicone coated.

Details of Embodiments of the Invention The invention was developed to avoid the waste associated with billboard advertising, printable banners and interior and exterior shop displays that are currently not recyclable. However, the product can have a variety of different uses including labels and all kinds of signage.

The product is based on a sheet of repulpable paper or card, which may be coated or uncoated. Repulpable paper may be repuplable or de-inkable and so satisfy the printed paper repulpable requirement for adding to the repulping/recycling stream. The paper may have a weight of 20-1000 gsm, preferably 50 -500 gsm. Different uses of the product will generally be made from paper having an appropriate weight. For example, where the product is graphics paper, the paper weight may be 100-500 gsm, preferably 200 -400 gsm. Alternatively, where the paper is label stock, the paper weight may be 50-120 gsm, preferable 80 -100 gsm.

The paper product comprises at least one layer of a repulpable printable lacquer. The lacquer can be printed on to provide the signage or label. The lacquer will generally be polyacrylate based, for example lacquers available from Solar Inks. Ideally the coating will have a weight of between 5 -15 gsm, preferably 7 -13 gsm and more preferably 8 -12 gsm. The lacquer provides a printable surface, but also provides moisture resistance to the paper product, enabling the product to have a minimum of 6 months outdoor durability in a typical Northern hemisphere weather conditions, winter or summer. The lacquer will typically be coated onto the paper layer, using a standard coating method, such as gravure, Mayer rod, slot die, or any other suitable method. It is then dried.

None, one or both sides of the sheet, including any side not coated with lacquer is coated with a repulpable pressure sensitive adhesive. Typically, the adhesive will be a polyacrylate based adhesive. For example, a standard permanent acrylic pressure sensitive adhesive may be used. The adhesive may be permanent or removable. While the use of a coating of a pressure sensitive adhesive is optional, usually such a coating will be provided.

Immediately after application, the pressure sensitive adhesive (if provided) is covered by a release liner, also known as a release layer or release film. This may be any paper or synthetic layer which can be easily removed from the adhesive before the product is adhered for use.

The product is generally provided as reels as per the market requirement and may be cut on a slitting machine or the like to the appropriate size.

For use, printing will be applied to the lacquer layer. The product is printable by both UV ink and latex ink technology, such as typically used on wide format digital inject machines. Examples of the machines using these inks are HP 360 Latex printer, Epson resin ink (latex) Surecolor SC-R5000, Colorado UV gel printer, Mimaki UV flatbed printer, Epson SC-V7000 UV flatbed and many other manufacturers equivalents. Where the printing is to create labels, the printing may be UV flexo, lithographic or gravure printing.

Manufacture of the product starts with a standard roll of repulpable paper of the appropriate weight for the ultimate use. This is then coating in the lacquer using a printable aqueous, solvent or 100% solids lacquer, using a coating method such as gravure, Mayer rod or slot die. The coating is then dried and rewound onto the drum.

The PSA is applied in a separate process, with the PSA being applied to the side not coated with the lacquer. This process also involves covering the PSA with the release layer.

Alternatively, the coating could be applied the other way round, i.e., the PSA is applied first, and covered with the release layer, and then the lacquer is applied in a separate coating process, to the uncoated side of the paper.

Finally, the paper product may be cut into appropriate sizes.

The finished construction of the paper product comprises a top layer of printable lacquer, a main body of the repulpable paper, optionally a lower layer of a printable lacquer, and optionally a lower layer of PSA together with a release layer over the PSA. Typically, the finished product has a width of 200 mm to 3000 mm.

For use, the printing can be applied to the lacquer layer, appropriate for use. For example, using UV gel inks on a UV Colorado wide format printer. Before application into a chosen position the release later is removed, and pressure is applied to adhere the product in place.

After use the product can be recycled, involving repulping of the paper. As all of the elements of the product are repulpable, the whole product is suitable for inclusion in the repulping and recycling stream.

Details of Embodiments of the Invention To help understanding of the invention, a specific embodiment thereof will now be described by way of example and with reference to the accompanying drawing, in which Figure 1 is a schematic drawing of the layers of the paper product according to a first embodiment of the invention; and Figure 2 is a schematic drawing of the layers of the paper product according to a second embodiment of the invention.

The invention relates to the production of a paper product that is fully recyclable. Many paper products, in particular those used in signs, advertising, marketing or labelling, include a plastic element which cannot be separated. This renders the whole product non-recyclable. For example, paper products used on outdoor advertising hoardings is required to have a level or durability in typical weather conditions for the area. This is likely to include exposure to rain and to sun. Previous products have typically included top layer of plastic material designed to protect the paper from the weather, resulting in a product having a durability longer than its intended life. Such hoardings are typically changed every 3 -4 months and thus a paper product is generally designed to have a durability of approximately 6 months.

However, such a plastic top layer cannot typically be removed, which means that the product is unsuitable for recycling.

The object of the invention is therefore to provide a paper product that can be recycled.

The paper product of the invention is based on a sheet of repulpable paper. Referring to Figure 1, the repulpable paper forms the central layer 2 of the product.

The paper may be any type of repulpable paper or card. For example, the paper will usually be white or cream, but may also be coloured. In addition, the paper may be coated or uncoated. The paper will generally be a wood free repulpable paper and may include a quantity of previously recycled paper pulp. Such paper is usually manufactured onto a roll or drum, with a width of between 200mm and 3000mm. Paper having a weight of 20 gsm to 1000 gsm is typically used.

The term repulpable is generally understood to mean paper that is suitable for entering the repulping / recycling process and can be repulpable or de-inkable.

The top layer 1 of the product is a repulpable printable lacquer. This is applied to the paper layer 2 as an aqueous, solvent or 100% solids lacquer, using a gravure, mayer rod, slot die or any other suitable method. The paper with its lacquer coating is dried and rewound onto its roll or drum.

The lacquer provides a surface that is suitable for printing and also provides a level of moisture resistance that enables the paper product to have a life span of at least 6 months outdoors in typical northern hemisphere weather conditions, including rain, sun and frost.

The lacquer can be any suitable type, in particular a polyacrylate based lacquer, such as available from Solar Inks. Application of the lacquer at a rate between 5 gsm and gsm provides the optimal protection to the paper layer 2 while maintaining repulpability of the product.

Following application of the repulpable lacquer layer 1, drying and rewinding, a lower layer 3 of a repulpable pressure sensitive adhesive is applied to the side of the paper layer 1 that is not already coated with the lacquer layer.

The pressure sensitive adhesive may be any such adhesive suitable for use of paper and that fulfils the requirements of the paper repulping and recycling process. For example, a polyacrylate adhesive may be used, such as Aquapal AD5625 from PAFRA Adhesives may be used.

The repulpable pressure sensitive adhesive 3 is applied to the paper using any suitable technique, such as gravure, mayer rod or slot die.

Following application of the adhesive, it is covered by a release layer 4, also known as a release liner or release film. The release layer 4 can be any suitable material having compatibility for use as a release layer with the pressure sensitive adhesive chosen. For example, the release layer 4 may be a paper or synthetic release layer capable of being removed from the pressure sensitive adhesive. In particular a silicon coated glassine paper may be used, such as 60 gsm siliconized one side, yellow glassine liner from Itasa, Spain. An alternative release paper could be used such as a 120 to 150gsm double-sided, polyethylene coated, 1 side silicon release paper, such as is available from Mondi or Felix Schoeller.

In some embodiments, the starting point may be a roll of repulpable paper 2 already coated on one side with a repulpable adhesive 3, covered by a release layer 4. Here the preparation of the product of the invention involves the application of a repulpable lacquer layer on the free side (namely the side no covered with the adhesive) of the paper 2.

In other embodiments, the starting point may be a roll of repulpable paper 2, to which a layer of repulpable pressure sensitive adhesive 3 is applied and covered by a release layer 4 and then rewound, with a layer of a repulpable lacquer 1 being subsequently applied to the free side (namely the side without the adhesive) of the paper.

Thus, the finished construct of the paper comprises a top layer of a repulpable lacquer 1, a central layer of repulpable paper 2 and a lower layer of a repulpable pressure sensitive adhesive 3, which is protected with a release layer 4.

The paper product will then be converted according to market requirements, for example, it may be cut into appropriate sizes, including smaller reels, using appropriate requirement such as a slitting machine.

In use, printing will be applied to the lacquer layer 1 of the paper product, the product having been cut to an appropriate size. The printing may use UV ink and Latex ink technology. These inks are of the type used on wide format digital inkjet machines available in the digital printing marketplace. Examples of the machines using these inks are HP 360 Latex printer, Epson resin ink (latex) Surecolor SC-R5000, Colorado UV gel printer, Mimaki UV flatbed printer, Epson SC-V7000 UV flatbed and many other manufacturers equivalents.

Once at the site of use, the release layer 4 will be removed and the product pressed into it site, for example an advertising hording, or on a product as a label.

The paper product has a wide variety of uses including die-cutting labels, pricing labels, bar code labels, QR labels, picture or diagram printed labels, wide formal printed graphics for sign and display use, all forms of advertising and marketing leaflets and signs.

Thus, the invention provides a paper product suitable for use on outside advertising hoardings, as well as general inside and outside use on signage, advertising and labelling, which is fully repulpable and/or recyclable.

Referring now to Figure 2, the product shown therein is very similar to that of Figure 1, with the exception that both sides of the paper 102 are coated with a layer of repulpable printable lacquer 101, before one side is coated with a repulpable pressable sensitive adhesive 103. As in Figure 1, the PSA is provided with a release layer which is removed before use.

Details of the materials is as set out for Figure 1.

In addition, the method of manufacture is also very similar. Initially the sheet of repulpable paper or card 102 is coated in both sides with layers of repulpable printable lacquer 101, before being dried and rewound. One side of the sheet is then coated with a layer of pressure sensitive adhesive 103, and a release layer 104 fixed thereover.

In yet another embodiment, not shown, both sides of a sheet of repulpable paper or card are coated in a layer of repulpable printable lacquer. One or both sides of the sheet may then be printed before both sides are coated in a repulpable pressure 20 adhesive before being covered in a release layer.

In other embodiments, the PSA layer may not be present, the product comprising a repulpable sheet of paper or card having a coating of a repulpable printable lacquer on each side. However, most embodiments will be provided with a pressure adhesive coating on one side, to enable ease of attachment to a surface.

Claims

CLAIMS1 A printable paper product comprising:-a sheet of repulpable paper or card; one or both sides of the sheet being coated with a repulpable printable lacquer; and none, one or both sides of the sheet being coated with a repulpable pressure sensitive adhesive; wherein each side of the sheet has at least one coating.
2 The printable paper product according to claim 1, wherein at least one side of the sheet is coated with a repulpable pressure sensitive adhesive.
3 The printable paper product according to claim 1 or claim 2, further comprising a release liner over the or each repulpable pressure sensitive adhesive layer.
4. The printable paper product according to any of claims 1 -3, wherein the repulpable printable lacquer layer is a polyacrylate based material.
5. The printable paper product according to any preceding claim, wherein the weight of the repulpable printable lacquer layer is between 5 gsm and 15 gsm.
6 The printable paper product according to any preceding claim, wherein the repulpable paper or card is wood free.
7 The printable paper product according to any preceding claim, wherein the repulpable card or paper has a weight of between 20 gsm and 1000 gsm.
8 The printable paper product according to any preceding claim, wherein the repulpable pressure sensitive adhesive is polyacrylate based.
9. The printable paper product according to any preceding claim, wherein the or each repulpable pressure sensitive adhesive is permanent or removable.
10. The printable paper product according to claim 3 or any claim dependent thereon, wherein the release liner is a silicone coated glassine paper.
11.A method of manufacturing a printable paper product comprising:- (i) providing a sheet of repulpable paper or card; (ii) applying a coating of a repulpable printable lacquer over one or both sides of the repulpable paper or card sheet; (-i) applying a coating of a repulpable pressure sensitive adhesive over none, one or both sides of the repulpable paper or card sheet, wherein each side of the sheet has at least one coating.
12. The method according to claim 11, where the method comprises applying a coating of a repulpable pressure sensitive over one or both sides of the sheet of repulpable paper or card.
13. The method according to claim 11 or claim 12, wherein step (ii) further comprises applying a release layer over the or each repulpable pressure sensitive adhesive Of provided).
14. The method according to claim 12 or claim 13, wherein the sheet of repulpable paper is coated on one or both sides with the repulpable lacquer and then in a second pass is a coated on the other side with the repulpable pressure sensitive adhesive
15. The method according to claim 12 or 13, wherein the sheet of repulpable paper or card is coated with the layer of repulpable pressure sensitive adhesive, and then coated on the other side with a layer of repulpable lacquer.
16. The method according to any one of claims 11 -15, further including the step of cutting the product into shorter or narrower lengths and widths for further use.
17. The method according to any one of claims 11 -16, wherein the repulpable printable lacquer layer is a polyacrylate based material.
18. The method according to any one of claims 11 -17, wherein the weight of the repulpable printable lacquer layer is between 5 gsm and 15 gsm.
19. The method according to any one of claims 11 -18, wherein the repulpable card or paper has a weight of between 20 gsm and 1000 gsm.
20. The method according to any one of claims 11 -19, wherein the repulpable pressure sensitive adhesive is polyacrylate based.