TECHNICAL FIELD

The disclosure relates to a method for printing a material for an absorbent article.

BACKGROUND

Absorbent articles such as sanitary napkins, panty liners and diapers sometimes include colored regions to highlight various sections of the article such as the location of the absorbent core in the crotch part of the article. An ink may be printed on the topsheet material or any other material or layer of the article prior to the production of the article or may be printed in line. Topical additives such as lotions may be added to the article in order to provide a skin condition benefit for the user of the article. WO2017007398A1 discloses the addition of ink and additives by a rotary printing device such as by flexographic printing. Flexographic printing of skin beneficial agents/additives enables vast possibilities to add agents to materials for absorbent articles. The skin beneficial agents are to be located directly against the human body. There is still a need to improve the printing methods for the addition of additives to materials for absorbent articles.

SUMMARY

The present disclosure provides a solution for print synchronization for rotary printing devices in relation to materials for production of absorbent articles.

The invention concerns a method for alignment of a pattern printed on a material for an absorbent article by a rotary printing device according to claim1. The method comprising providing a first composition from a first chamber; providing a second composition comprising a detectable agent from a second chamber; wherein the first composition from the first chamber and the second composition from the second chamber are supplied to the same anilox roller or directly to the same rotary printing cylinder; and printing the first and second compositions on the material for an absorbent article by a rotary printing cylinder.

The first and second chambers may be combined in one chamber with two separate compartments. The first and second chambers may be horizontally oriented in relation to the anilox roll. The first and second chambers may be vertically oriented in relation to the anilox roll and the outlets from the chambers may be horizontally orientated in relation to the anilox roll.

The rotary printing device may be a flexographic printer.

The anilox roll may be banded. A banded anilox roll may have different transfer volumes and/or line counts for the first and second compositions respectively. Areas with different transfer volumes and or line counts may be separated by an area/band without transfer.

The first composition may comprise a functional agent. The first composition may comprise a functional agent selected from a skin beneficial agent, an adhesive, a cooling or heat generating agent, an antimicrobial agent. The first composition may comprise a water emulsion of a skin beneficial agent. The first composition may comprise microcapsules. The first composition may comprise water-based ink. The first composition may comprise a mixture of any of the above.

The second composition may comprise a detectable agent that emits light in the UV or visible light spectra. The second composition comprising a detectable agent may also comprise the first composition as mentioned above.

The first and second compositions may be printed with different printing patterns. The first and second compositions may be printed with different frequencies.

The first composition may be printed >0.1 mm from a first edge of the material and up to and including 99% of the width of the material, such as 95%, such as 80% of the width of the material. The second composition may be printed >0.1 mm from a second edge of the material and up to and including 50% of the width of the material, such as less than 40%, such as less than 30%, such as less than 20% of the width of the material.

The detectable agent may form a sync mark. The size of the sync mark may be >0.1 mm, such as more than 1 mm and less than 50 mm. The size of the sync mark may be 10×20 mm.

The detectable agent may be detected by means of a sensor or camera. The material for the absorbent article may be converted by means of inline converting into an absorbent article for personal care use.

The method may further comprise an additional step of removing the sync mark, such by cutting off the edge part of the material comprising the sync mark.

The material for the absorbent article may be a nonwoven, airlaid, film, laminate, highloft nonwoven, cellulose tissue or a combination thereof.

DETAILED DESCRIPTION

The printing method according to the disclosure uses two chambers for the rotary printing device, or one chamber with two different compartments. The printing equipment, in case of a flexographic printer, uses the same anilox roller, cliché and printing cylinder for the printing method, however two different chambers to supply printing compositions to the same anilox roller. Chamber one may contain a composition that may comprise skin beneficial agents/additives and chamber two may comprise a composition comprising a detectable agent, such as a UV fluorescent ink, to form a detectable sync mark on a material for an absorbent article.

The printing method enables production of a material that will in most part contain the pattern of the first composition that may comprise skin beneficial agents/additives, but at least a transversal edge part of the material may comprise a composition comprising a detectable agent, such as an ink printed sync mark of UV fluorescent ink. The sync mark may aid in the further processing of the absorbent article to synchronize the parts of the material containing composition one, that may comprise additives, to predetermined locations on the absorbent article. An edge part of the nonwoven material carrying the detectable agent may later be removed during the processing of the article, if needed. Chamber two may comprise the same composition as ink chamber one which enables easy measurement and control of added amounts of the additives to the material, while not interfering with the part of the material destined for contact with the user of the absorbent article.

As used herein “beneficial agent” means a beneficial additive bringing a physical, medical, pharmacological, chemical, dermatological or emotional benefit to the user of the article.

According to one embodiment “beneficial agent” means a beneficial additive bringing a physical, medical, pharmacological, chemical, dermatological or emotional benefit to the user of the article other than delivered by a perfume or scent.

The beneficial agent may be a skin beneficial additive.

As used herein “absorbent article” means an article selected from a sanitary napkin, a panty liner, an incontinence pad, an incontinence diaper, feminine diaper, a belted diaper, baby diaper.

The compositions may comprise at least a binder and a beneficial agent. The compositions may further comprise an ink that may be a standard formulation known to the skilled man in the art. The ink may be water-based or solvent-based, which may include colored pigments or dyes or be colorless. The ink may also include typical printing additives well known to those skilled in the art such as solvents, co-solvents and processing aids. Solvent may include among other alcohols, esters, aldehydes and water. Binders may be, but are not limited to, polymers, resins, emulsions and mixtures based on styrenes, acrylates, acetates, alkydes, polyurethanes, nitrocellulose or other cellulose derivatives, polyglycols, polyvinylbutyrates, polyvinyl alcohols, polyvinyl pyrrolidone and derivatives or mixtures thereof. Constituents such as dispersants, surfactants, wetting aids, defoamers, anti-foaming agents, waxes, silicones, viscosity modifiers, pH regulators, anti-slip agents and preservatives may also be present in the ink formula together with one or more of the beneficial additives. The binder in the ink composition ensures the hardening of the ink.

The beneficial agent may be microencapsulated and added to the ink as an emulsion or as a powder. The concentration of microcapsules in the resulting ink composition and the amount of ink composition applied to the absorbent article may be determined by the skilled man in the art by routine experiments and formulated for each specific use. The concentration of microcapsules depends on the used beneficial agent and the desired effect of the article. The amount of ink applied to the absorbent article will depend on the composition of the ink and on the desired pattern on the article. The amount of ink needed may vary also depending on the surface absorbency.

The concentration of microcapsules on the article may be at least 0,001 g/m2, or at least 0.01 g/m2or at least 0.1 g/m2and below 5 g/m2, or below 1.0 g/m2or below 0.6 g/m2. The concentration of microcapsules on the article may range between 0.001-5 g/m2, or 0.01-1 g/m2or 0.05-0.6 g/m2.

The size of any added microcapsules may be at least 1 μm, or at least 5 μm, or at least 10 μm and may be below 100 μm, or below 70 μm, or below 40 μm. The size of the microcapsules may range between 1-100 μm. The size of the microcapsules may be 5-70 μm. The size of the microcapsules may be 10-40 μm.

The technique of microencapsulation of additives is known for other uses such as cosmetics. Examples of companies producing such microcapsules are Devan Chemicals, Belgium; Encapsys, USA; Micro Capsule Technologies, France; and Robert Blondel, France, Salvona Technologies, USA.

Microencapsulation may be done through polymerization in oil-in-water emulsions to create dispersions or dry powders or water-in-oil emulsions. The microcapsule material may be of a material known to the skilled man in the art. Typical shell materials include polymeric, melamine, and silica based compositions. In one embodiment the microcapsule material is a composite of silicone and melamine polymers. The capsule material may be of natural origin such as alginate.

The beneficial agent may be selected from extracts from plants, herbs, fruits, seeds, spices and oils.

The beneficial agent may be a hydrophobic or lipophilic substance or additive.

The beneficial agent may be selected from almond oil, argan oil, sesame seed oil, jojoba oil, grapeseed oil, shea butter, olive oil, coconut oil, avocado oil, limonene, linalool, geraniol, citral, coumarin, hibiscus,Lavendula augustifolia, calendula, chamomile, peppermint, sandalwood, peach, mango, apricot, sea buckthorn, coffee, vanilla, chocolate, menthol, xylitol.

The beneficial agent may also be selected from carbamid, glycerin, dimethicone, tocopheryl (vitamin E), ascorbic acid (vitamin C), allantoin, thymol, salicylates.

An advantage of microencapsulation of beneficial agents is that agents that would otherwise be incompatible with the ink can be added and properly dispersed as microcapsules. A further advantage is that the release of the agent is gradual during the use of the article and the scent, if any, will be reduced in the manufacturing operation as well as on the shelf.

The compositions are applied by printing. By printing we herein mean a precise application of a fluid to form a coating or other dry layer on a substrate. By precise we mean that the medium will be placed in designated areas on the substrate, rather than in a poorly controlled fashion such as when using a spraying or extrusion technique. The print is by a rotary printing device, e.g. flexoprint, screen print or rotogravure. The printing techniques are further described in “Handbook of print media: technologies and production methods”/ed. Helmut Kipphan; Springer, 2001; ISBN 978-3-540-29900-4.

The compositions may be applied by a synchronized in-line print technique, such as by flexoprint, allowing for an exact placement of the compositions.

The steps of printing may be incorporated as inline steps in a process of manufacturing absorbent articles, or the layers may be printed off-line. It is also possible to print the layers before or during assembly of the components of the absorbent article.

After printing any solvents will evaporate so that the composition dries almost instantaneously. However, a drying step may be added, such as blowing hot air on the printed surface.

The compositions may be applied in selected areas as desired, and in any desired pattern. The present method allows very accurate patterns and fine lines and dots to be formed.

When arranged in the absorbent article, the top sheet has body facing surface and a garment facing surface. The compositions may be applied to one or both of said surfaces. By applying the ink compositions on the body facing surface the user obtains a direct access to beneficial agents.

Depending on the location of the composition various advantageous functional effects can be obtained. Examples of patterns of with different functions are given below. These patterns can be used individually but may of course advantageously be combined to achieve the desired characteristics of the absorbent article.

The composition may be printed on an area or zone of the article selected from:along longitudinal side edges of the crotch portion;a central area of the crotch portion;a central area of the front portion;a central area of the back portion.

The absorbent article may further comprise a wing extending from each longitudinal side edge of the article and the composition may be printed on an area of said wings.

The printed areas or zones may be an area or zone having an oval, circular, moon, heart, arrow shape etc. and placed in certain regions of a product to give a unique function.

The absorbent article comprises at least a topsheet layer and if desired also a backsheet layer and an absorbent layer arranged between the topsheet and the backsheet layers. Each layer of the absorbent article has a garment facing surface and a body facing surface, and the compositions may be applied to any of said surfaces. The composition may be added to an acquisition layer located beneath a topsheet.

Detectable agents may be an ink such as a waterbased ink, optical brighteners, optical brightening agents (OBAs), fluorescent brightening agents (FBAs) or fluorescent whitening agents (FWAs).

The absorbent article may comprise a body facing topsheet of a nonwoven, a film or a laminate thereof or a foam and a back sheet of a liquid impervious polymeric film material or a laminate of a film and a nonwoven material and an absorbent layer comprising pulp and/or superabsorbent material and/or a fibrous web.

The backsheet material may be breathable or non-breathable. The back sheet is facing away from the user during use and is opposite to the body facing topsheet layer of the absorbent article. A fastening means may be applied on the garment facing side of the back sheet, which may be covered by a release paper or single wrap.

Activation of microcapsules may be performed by mechanical activation wherein the capsule breaks up by a shearing force or by pressure upon contact. When the absorbent article is used the microspheres will break due to the user's movements. Not all microcapsules will break at the same time as some may be buried further down in the material and there will thus be a slow, continuous and beneficial release of the agent during use of the article. A long-lasting effect may thus be achieved.

Other means of activating microcapsules in addition to mechanical rupture are e.g. change of pH, dissolution, temperature change, osmosis, photolytic release, ultrasonication, biodegradation, diffusion and erosion.

The application by print allows for a precise placement of a delicate printed pattern in chosen areas on the article, compared with when an additive is applied for example as a constituent of the spin finish on a topsheet, in a so-called cocktail, which is commonly used by nonwoven suppliers.

