FR2739838A3 - Varnish dried by UV light, used as barrier agent in packaging - Google Patents

Abstract

Barrier agent intended for packaging comprises a mixture of at least one fluorinated polymer; a methacrylate; acrylic resins in aqueous solution; waxes; and silicones. Also claimed is process for treating packaging with barrier agent. Preferably barrier agent contains 4-10 wt.% fluorinated polymer; 10-30 wt.% methacrylate; 30-50 wt.% acrylic resins; 1-4 wt.% surface tension reducer; optionally 5-20 wt.% pore-blocker (for use with porous substrates); and 10-15 wt.% water. Agent shows permeability to water vapour 20-120; carbonic acid gas 50-150; and oxygen 30-100.

Description

AN ULTRA-VIOLET THERMO-WELDABLE VARNISH
USED IN BLISTER OR OTHER
ITS APPLICATIONS AND IMPLEMENTATIONS
IN THE PACKAGING INDUSTRY
The invention relates to a UV varnish, a method of treating a packaging material, a packaging or a packaging accessory using said varnishing agent as well as the materials, packaging and accessories for packaging comprising said UV varnish.

 Complexes incorporating polyethylene, polypropylene and other plastic or metallic films are already known in the packaging, paper and cardboard industry, which constitute a barrier to water, to vapor from water, solvents, grease, odors, etc. These barrier materials are particularly useful in the case of packages of hydrophilic products such as in particular washing powder, dehydrated vegetables and fruits, flours, sugars, plant protection products, plant health products, etc.

 A complex comprising polyethylene - for example a polyethylene film sandwiched between a sheet of cardboard and a sheet of paper, the assembly being made integral has a certain number of drawbacks: material cost, processing difficulties, recycling difficulties packaging materials in accordance with ecological standards, etc.

 The invention therefore aims to overcome these drawbacks by proposing a packaging material, a packaging or a packaging accessory which at the same time meets the requirement of a batten varnish, of solvents, of greases, of odors, etc. desired while being, simultaneously, of an acceptable cost and in conformity with the requirements posed by today's ecology.

 To this end, the invention provides a weldable varnish characterized in that it comprises a mixture of at least one fluoropolymer, a methacrylate, a set of acrylic resins in aqueous solutions, waxes and silicas, a photo initiator adapted.

 If necessary, the agent comprises a step-down in surface tension, a biocide, a bactericide.

 According to another characteristic, the UV varnish specially intended for a substrate having a high porosity, comprises a sealer.

 The invention also relates to the applications of such a UV varnish to a packaging material, to a packaging or to a packaging accessory.

 The other characteristics of the invention will be clearly understood on reading the description which follows.

 The invention firstly relates to a UV drying varnish.

 This UV varnish is intended to be applied in the packaging, paper and cardboard industry, the applications considered also forming part of the invention.

 The varnish in question comprises a mixture of at least one fluoropolymer, a methacrylate, a set of acrylic resins in aqueous solutions, waxes and silicas and a photo initiator.

 The UV varnish also includes and as far as necessary depending on the application considered, a surface tension step-down.

 The water is demineralized or osmosed with an appropriate TH.

 Acrylic resins provide the mechanical strength desirable for the applications under consideration.

 When the barrier agent is intended for a substrate having pores (such as cardboard or paper), it is intended that it comprises a pore-blocker such as dextrins, synthetic starches, or equivalent, CMCs, HEC, etc.

It goes without saying that it is the right proportion (by weight or by volume) of certain products or family of products which constitute the barrier agent. The main products to remember are:
- fluorinated polymers
- methacrylates
- acrylates
- surface tension reducers, fluorinated or not
- sealers
- the water
- biocides and bactericides.

- waxes
- silicas
It goes without saying that each compound which has been indicated can be replaced by any other functionally equivalent compound.

The barrier agent must have the following characteristics:
- excellent adhesion to any support: cardboard,
paper, metal, plastic, textile, even
glass, whether this support is complex or not, whether
rigid or not, in the form of a strip, sheet, wire, plate,
flank, flat or not, or shaped in volume, thin or thick.

- exceptional waterproofing with battens, steam,
gas, herbs, oil, grease, etc.

 Its gloss is also excellent, which is particularly advantageous in the field of packaging.

 It constitutes a barrier to odors which is also advantageous when the support is made of cardboard.

 It allows temperature constraints up to 1200C or more.

 In certain cases, it makes it possible to reduce the products or preservatives added to food.

 It is heat and HF sealable.

 It allows great flexibility of the protective film and can absorb large deformations (elongation or shrinkage).

 It is fully recyclable, biodegradable and compatible with direct food contact.

 Depending on the case, the material is opaque or transparent.

 It has the best value for money in terms of barrier agent.

 Its flash point is above 300 C. It is stable in an acid medium at pH 3 and an alkaline medium up to pH 10.5.

According to one embodiment, the barrier agent has the following permeabilities:
- with steam between 20 and 120 gp / m2,24h (ASTM
Standard Specification E 96 - 66 - Procedure E)
- with carbon dioxide between 50 and 150 N cm3./m2,24h.atm (ASTM
Standard Specification D 1434 - 66)
- with oxygen between 30 and 100 N cm3.M / m2,24h.atm (ASTM
Standard Specification D 1434 - 66)
Finally, this agent can be printed with suitable inks.

 Such a barrier agent is intended to be associated with a packaging material or with a packaging or even with a packaging accessory or with the material for producing such an accessory.

 The packaging material considered can be cardboard, wood such as unrolled or unrolled wood, plastics such as PE, PPPE, PET, PVC, PVDC, polystyrenes, etc. It may possibly even be glass or textile materials.

 The packaging considered here is of all types such as in particular trays, canisters, boxes, bottles and flasks, cases, dose packaging, containers, envelopes, cases, covers, bags in box, pouches, jars, sachets and bags, tubes, this list being purely indicative and not limiting.

 The packaging material considered here is either in the form of a strip or sheet or is prepared to constitute a packaging such as a blank for cardboard or paper. The packaging material can also be in filiform form (for example for ties) or in the form of a sleeve (for labels or containers) or in volume (such as wedging foam). Its shape can be flat or not. This packaging material can also be more or less thin or thick and also includes complexes, foams and nonwovens.

 The packaging accessories considered are for example stoppers, wedging products, glues and adhesives, inks, labels, closures, films and sheets, seals, links, lids, this list being purely indicative and not limiting.

 According to a first embodiment, the barrier agent is incorporated into the mass of the material constituting the packaging or the packaging accessory, even during the manufacture of this material.

 According to another possible embodiment, the barrier agent is applied in the form of a layer on the material for the packaging or the packaging accessory or even directly on the packaging itself.

 This layer can have a non-limiting thickness of the order of a few microns to a few millimeters.

 The production of such a layer can be done according to different methods such as coating, soaking, spraying, application, and more generally by the techniques used in the field of printing and packaging (gravure, flexo, etc.). .

 Where appropriate, it is intended that the material for the packaging or the packaging accessory incorporates a barrier agent and that a layer of barrier agent, strictly identical or only similar to the previous one, is deposited on the protective material. packaging or packaging accessory or on the packaging.

When the barrier agent is deposited in a layer on the packaging material or packaging accessory, or on the packaging, several variants can be envisaged, depending on the applications considered:
- Deposition on the entire surface of the material
packaging or packaging accessory or packaging
or on only part of this surface. In
particular, and in the case of a packaging material or
packaging in the form of a sheet or
of a strip, the barrier agent can be deposited on one
and / or the other of the two sides of the material, but
preferably, at least on the internal face in contact
packaged content.

- Deposit of one or more superimposed layers of agent
fence.

- Deposit of the barrier agent directly on the material
packaging or packaging accessory or packaging or
indirectly after prior deposit of a primary
protection or any functional layer or sheet
desired.

 Once the barrier agent has been deposited on the packaging material, the packaging or the packaging accessory, suitable drying is carried out, if necessary.

 This drying is carried out by simple natural evaporation or by an appropriate heat treatment (hot air, infrared, microwave, etc.).

In a typical application of the invention, a coated cardboard having a thickness of 7 mm is used as packaging material; on the front: a four-color printing is carried out with the application of a gloss varnish,
on the back: an application of the barrier agent according to the invention is carried out (with sealer).

 This example of implementation is particularly well suited to the packaging of a product such as detergent powder, the latter being in contact with the packaging on the back side.

 The formulation of the barrier agent is compatible with products having nonionic, anionic or cationic structures.

 The barrier agent can be the subject of various applications in the field of packaging. In particular, it is well suited for packaging detergents with a high load of sodium aluminate or potassium hydroxide, for cheeses, cookies, pastry, cocoa, more generally fatty products, frozen foods, liquids , syrups. Another application concerns individual food portions, survival rations, etc. Applications are also possible outside the food sector.

Claims (14)

 1. Barrier agent intended for packaging, characterized in that it comprises a mixture of at least one fluoropolymer, of a methacrylate, of acrylic resins in solution in aqueous mixture, of waxes and of silicas.  2. Barrier agent according to claim 1, characterized in that it further comprises a surface tension step-down.  3. Barrier agent according to any one of claims 1 and 2, characterized in that it is specially intended for a substrate having pores and that it further comprises a sealer.  4. Barrier agent according to any one of claims 1 to 3, characterized in that it comprises from 4 to 10% by weight of fluoropolymer, of the order of approximately 10 to 30% of methacrylate, from around 30 to 50% of acrylic resins, around I to 4% of surface tension reduction, around 5 to 20% of filler if necessary and around about 10 to 15% of water.  5. Barrier agent according to any one of claims 1 to 4, characterized in that it has a permeability to water vapor between 20 and 120; permeability to carbon dioxide between 50 and 150; an oxygen permeability between 30 and 100 (according to standard ASTM E 96-66 and D 1434-66).  6. Method for treating a packaging material or a packaging or a packaging accessory, characterized in that it uses the barrier agent according to any one of claims 1 to 5.  7. Method according to claim 6, characterized in that the barrier agent is incorporated into the packaging material or packaging accessory and / or applied as a layer.  8. Method according to claim 7, characterized in that the layer has a thickness of a few microns, in particular 1 to 20 microns without limitation.  9. Method according to claim 6, characterized in that the packaging material or packaging accessories is cardboard, paper, wood, plastic, glass, textile material, in the form strip, sheet, prepared to constitute a packaging in filiform form, in plate, in sleeve, flat or not, shaped in volume, complex or not, rigid or not.  10. Method according to claim 6, characterized in that the packaging is trays, cans, boxes, bottles, flasks, cases, dose conditioning, containers, envelopes, cases, covers, bags in box, pouches, pots, sachets, bags, tubes.  11. Method according to claim 6, characterized in that the packaging accessories are stoppers, wedging products, glues and adhesives, inks, labels, closures, films and sheets, seals, links, covers.  12. Method according to claim 6, characterized in that the barrier agent is applied by coating, soaking, spraying, application or by techniques used in the field of printing and packaging (gravure, flexo in particular) .  13. Method according to claim 6, characterized in that it comprises a drying step after the deposition of the barrier agent in the form of a layer.  14. Packaging material obtained by the method according to claim 6 characterized in that it comprises a coated cardboard substrate, and on the back thereof a layer of barrier agent and, on the front, a protective primer and possibly a varnish.