Lining-free elution label

Abstract

A linerless elution label (100) is provided that includes a paper-based facestock (101, 201) and a pressure sensitive adhesive (102). The paper-based facestock (101, 201) includes a base paper (206) and a release layer (203), the release layer (203) and the pressure sensitive adhesive (102) being disposed on opposite sides of the base paper (206). The pressure sensitive adhesive (102) comprises a water-based acrylic emulsion polymer composition, the pressure sensitive adhesive (102) is sensitive to wash conditions, the base paper (206) comprises a wet strength resin, and the water absorption is 10 to 30 g / m2 measured according to ISO Standard 535 (contact time 60 seconds). Further, a label product roll comprising a linerless elution-type label (100) and a labeled article comprising an article and a linerless elution-type label (100) are provided. Furthermore, the use of a linerless elution-type label (100) and a method of manufacturing a linerless elution-type label web for providing a linerless label product roll are also provided.

Description

Technical Field

[0001] The present invention relates to a linerless wash-off label, a label product roll including the linerless wash-off label, and a labeled article including an article and the linerless wash-off label. In addition, the present invention also relates to the use of the linerless wash-off label and a method for manufacturing a linerless wash-off label roll to provide a linerless label product roll. Background Art

[0002] It is common practice to apply labels to the surface of containers in order to provide identification and / or information, e.g. about the contents of the container. In the case of returnable and / or reusable containers, there is a need for labels that are easily removable from the surface of the container by washing. In particular, the label needs to come off completely during washing, e.g. without leaving any adhesive residue on the container. Furthermore, in particular for returnable and / or reusable food containers, it may be important that in the event that the container has been opened, the label shows signs of opening. Furthermore, it is desirable to have labels that can be printed using a linerless printer. Summary of the invention

[0003] The present specification provides a linerless wash-off label that can be easily and quickly peeled off completely under mild washing conditions. In addition, the label can be printed using a linerless printer, and the label can seal a container and show signs of tampering when the container is opened.

[0004] According to one embodiment, a linerless wash-off label is provided, which includes a paper-based face material and a pressure-sensitive adhesive. The paper-based face material includes a base paper and a release layer, and the release layer and the pressure-sensitive adhesive are arranged on opposite sides of the base paper. The pressure-sensitive adhesive comprises a water-based acrylic emulsion polymer composition. The pressure-sensitive adhesive is sensitive to washing conditions, and the base paper includes a wet-strength resin and has a water absorption of 10 to 30 g / m2 measured according to ISO standard 535 (contact time 60 seconds). 2 .

[0005] In addition, a linerless label product roll is provided, which includes the linerless wash-off label described herein.

[0006] According to another embodiment, a labeled article is provided, which includes an article and a linerless wash-off label as described herein. The linerless wash-off label is adhered to the surface of the article by the pressure-sensitive adhesive of the linerless wash-off label.

[0007] Furthermore, there is provided the use of a linerless wash-off label as described herein for labelling an article.

[0008] According to another embodiment, a method for manufacturing a linerless wash-off label web is provided, the linerless wash-off label web being used to provide a linerless label product roll. The method comprises:

[0009] - Arrange the paper-based surface material or carrier as a substrate,

[0010] - coating the substrate with a pressure-sensitive adhesive,

[0011] - drying and / or curing of the pressure-sensitive adhesive on the substrate,

[0012] - in the case where the substrate is a carrier, transferring the pressure sensitive adhesive from the carrier to the paper-based facestock, and

[0013] - rolling the paper-based surface material with adhesive thereon into a roll of linerless wash-off label material,

[0014] The paper-based surface material includes base paper and release layer.

[0015] in,

[0016] The pressure-sensitive adhesive and release layer are arranged on opposite sides of the base paper.

[0017] The pressure sensitive adhesive comprises a water-based acrylic emulsion polymer composition,

[0018] Pressure sensitive adhesives are sensitive to washing conditions,

[0019] as well as

[0020] The base paper includes a wet strength resin and has a water absorption of 10 to 30 g / m2, measured according to ISO standard 535 (contact time 60 seconds). 2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A cross-sectional view of a linerless wash-off label is shown as an example, and

[0022] Figure 2 A cross-sectional view of a paper-based face stock is shown as an example.

[0023] The figures are schematic and not to scale. DETAILED DESCRIPTION

[0024] The solution will be described in more detail below with reference to some embodiments, but these embodiments should not be considered limiting.

[0025] In the present description and claims, unless otherwise stated, percentage values ​​relating to the amount of material are percentages by weight (wt%). Thickness is expressed in micrometers, i.e. μm. Temperature is expressed in degrees C, equivalent to °C. The following reference numerals and symbols are used in this application:

[0026] 100 Linerless Wash-Off Labels

[0027] 101,201 Paper surface material

[0028] 102 Pressure sensitive adhesive

[0029] 203 Release layer

[0030] 204 Thermal layer

[0031] 205 Pre-coating

[0032] 206 base paper

[0033] 207 Barrier layer

[0034] A label is a sheet of material applied to an article or item of different shapes and materials. The article or item may be a package. The label comprises at least one face stock material, also referred to as face stock or face layer. A typical method of attaching a label to an article or item is by using an adhesive. Labels comprising an adhesive layer are referred to as adhesive labels. The adhesive may comprise a pressure sensitive adhesive (PSA). Labels comprising a pressure sensitive adhesive may be referred to as pressure sensitive adhesive labels. Pressure sensitive adhesive labels are also referred to as self-adhesive labels.

[0035] The adhesive layer allows labels comprising PSA to adhere to most surfaces without the use of a second agent (e.g., solvent) or heating to strengthen the bond. In this case, the adhesive itself is pressure sensitive. Alternatively, the adhesive may be activatable so as to be pressure sensitive. When pressure is applied to the label at ambient temperature (e.g., between 15°C and 35°C), or for cold applications even at freezing temperatures below 0°C, or for hot applications at temperatures above 35°C, the PSA forms a bond so that the label adheres to the item / article to be labeled. Examples of pressure-sensitive adhesives include water-based (water-containing) PSAs, solvent-based PSAs, and hot melt PSAs. The label may further include other adhesives.

[0036] Labels can be used in a wide range of marking applications and end-use areas, such as marking food, household and personal care products, industrial products, pharmaceuticals and health care products, beverage bottles and wine bottles, other consumables, etc. Labels can provide information about the labeled product, such as product specifications. Information, such as the print of the label, can include human-readable information, such as images, logos, text and / or machine-readable information, such as barcodes, QR (quick response) codes. The surface of the labeled article / article can be, for example, plastic, glass, metal or paper. The labeled article / article can be, for example, a container, such as a bottle, a jar, a can, a can, a tin can, etc. Labels can also be applied to semi-rigid or flexible packaging (e.g., for packaging food).

[0037] The term "face" refers to the top substrate of the label, also known as face paper or face material. The face material can have a single-layer structure or a multilayer structure including at least two layers. The face material is a layer that is adhered to the surface of the product / article by an adhesive layer during the labeling process. The face material includes an adhesive side and a printing side. A combination comprising a face material and an adhesive can be referred to as an adhesive label. The face material can, for example, include a print to provide information and / or a visual effect. The printable face is suitable for printing by any known printing method, for example, gravure printing, flexographic printing process, offset printing, screen printing or relief printing. The print can be present on the top surface, back side, or both the top surface and back side of the face material. In addition, the label can include an additional layer, such as a top coating or an overlaminate, to protect the top surface and / or print of the label from friction or other external stresses. A coating or additional layer, such as a primer, can enhance the compatibility of adjacent layers or parts of the label, such as adhesion between layers. A label comprising a face material, a print layer and an adhesive can be referred to as a printed label.

[0038] The term "coil" refers to a continuous sheet of material. Coils are typically processed by moving on rollers. Between processing stages, coils can be stored and transported in roll form.

[0039] The term "machine direction" or MD refers to the direction in which the web is manufactured. The machine direction may also refer to the circumferential direction of a roll. The term "cross direction" or "cross machine direction" or CD refers to the direction transverse to the machine direction.

[0040] The present specification is intended to provide a linerless wash-off label. Generally speaking, the term "linerless label" refers to a label comprising a single-layer or multi-layer face stock and an adhesive on the face stock.

[0041] like Figure 1 As shown, the linerless wash-off label 100 disclosed herein includes a paper-based face stock 101 and a pressure-sensitive adhesive 102 , or consists of the paper-based face stock 101 and the pressure-sensitive adhesive 102 .

[0042] Wash-off labels, also known as washable labels, are labels that can be removed (detached) from the surface of the item to which they are attached during subsequent washing. Wash-off labels contain adhesives that are sensitive to washing conditions. Washability is required for recycling and / or reusing the labeled item. For example, reuse of food containers may require washability of the label.

[0043] A wash-sensitive adhesive is an adhesive whose adhesion decreases under wash conditions. A wash-sensitive adhesive is capable of reducing its adhesion (tack) under wash conditions. Wash conditions typically include alkaline conditions (washing solution) and / or elevated temperature.

[0044] The linerless wash-off label disclosed herein can be used to label an article to form a labeled article. The labeled article includes an article and the linerless wash-off label described herein. The linerless wash-off label is adhered to the surface of the article by the pressure-sensitive adhesive of the linerless wash-off label. The article can be a plastic article, a glass article, or a metal article. The article can be a container. The container can include a lid, and in the labeled container, one end of the linerless wash-off label is attached to the lid, and the other end of the linerless wash-off label is attached to the container. For example, the container can be a recyclable and / or reusable plastic food container.

[0045] Surface material

[0046] Paper-based facestocks may contain natural fibers as their raw material. Natural fibers refer to any plant material containing cellulose. Natural fibers may be wood-based. Paper-based facestocks are well suited to the growing trend of reducing the use of unnecessary plastic materials. In addition, paper-based labels may be configured to meet requirements that show signs of tampering when the container is opened.

[0047] The paper-based surface material includes a base paper and a release layer. The release layer and the pressure-sensitive adhesive are arranged on opposite sides of the base paper. The pressure-sensitive adhesive is arranged on the lower surface of the surface material, opposite to its printable upper surface.

[0048] The paper-based surface material also includes a heat-sensitive layer and a pre-coating layer. The paper-based surface material may further include a barrier layer. In one example, Figure 2 As shown, the paper-based facestock 201 includes the following layers in the following order: 1) release layer 203, 2) heat-sensitive layer 204, 3) pre-coating layer 205, 4) base paper 206 and 5) barrier layer 207. When the barrier layer is present, the barrier layer is the adhesive receiving surface of the linerless wash-off label. If there is no barrier layer, the base paper is the receiving surface of the adhesive.

[0049] To ensure washability of linerless wash-off labels, the facestock must allow water to penetrate and / or migrate to the bottom of the label. Therefore, the label must have a certain degree of hydrophilicity. The hydrophilicity of a label is expressed in terms of water absorption. Water absorption, also known as wettability, is determined by measuring the amount of water that a paper surface can absorb in a given time. Water absorption is a function of various paper properties, such as sizing, porosity, etc. Water absorption can be determined according to ISO standard 535, also known as the Cobb method.

[0050] The water absorption of the base paper of the linerless wash-off label facestock is 10 to 30 g / m2 when measured according to ISO standard 535 using a contact time of 60 seconds. 2 The conditioning of the water absorption test sample is carried out under the standard conditions specified in ISO Standard 187. In one example, the water absorption of the base paper of the linerless wash-off label face material is 15 to 25 g / m 2 , for example 20 to 25 g / m2 The water absorbency of the base paper is within the given range in both cases: when measured from the heat-sensitive layer / face material side (top side) and the reverse side (bottom side).

[0051] The base weight of the base paper is 70g / m 2 Up to 90g / m 2 , thickness of 70 to 90 μm. When measured according to ASTM D828, the MD tensile strength of the base paper is 5.0 to 7.0 kN / m, and the CD tensile strength is 3.0 to 5.0 kN / m. When measured according to ASTM D689, the MD tear resistance of the base paper is 400 to 420 mN, and the CD tear resistance is 450 to 470 mN.

[0052] The paper-based surface material, especially the base paper, contains a wet strength resin. The wet strength resin contained in the paper-based surface material plays a role in resisting the breaking force. In addition, the decomposition of paper fibers under washing conditions can be reduced. Wet strength resins include, for example, urea-formaldehyde (UF), melamine-formaldehyde (MF) and polyamide-epichlorohydrin (PAE). The wet strength resin of the base paper can be contained in the additive, and the amount of the additive can be 0.5 to 1.0 g / m 2 .

[0053] The base paper may include fibers, fillers, pigments, binders and additives. In one example, the base paper may contain 40 g / m 2 Up to 70g / m 2 The base paper may contain 4g / m 2 Up to 8g / m 2 An example of a filler pigment is calcium carbonate. The base paper may contain 1 g / m 2 Up to 3g / m 2 As mentioned above, the base paper may contain 0.5 to 1.0 g / m 2 Additives, including wet strength resins.

[0054] The purpose of the release layer is to enable the label material to be self-winding. This means that a linerless label web having a pressure sensitive adhesive on one side (bottom side) and a release coating forming a release layer on the other side (top side) can be self-winding around itself without there being a tendency for adjacent layers of the label web to block each other. The release coating forming the release layer can be silicone based or non-silicone based. The release layer can comprise one or more layers of release coating. The amount of release layer / release coating on the paper-based facestock can be 0.5 g / m 2 Up to 1.0g / m 2 , for example 0.8g / m 2 From a washability standpoint, the less release coating, the better.

[0055] In one example, the release coating is silicone-based. The silicone-based release coating may include UV-curable silicones, such as UV free radical silicones or cationic UV silicones. When a heat-sensitive layer is present in the paper-based surface material, a non-thermosetting release coating (such as UV-curable silicone) may be more preferred because the curing of such a coating does not heat the heat-sensitive components in the heat-sensitive layer.

[0056] When a paper-based surface material includes a thermal layer, the surface material can be referred to as a directly thermally printable surface material. The thermal layer provides thermal printability to the surface material. The thermal layer may include a color former (such as a leuco dye), a developer (preferably phenol-free), an absorptive pigment (such as calcined clay), a binder (such as PVA, i.e., polyvinyl alcohol), and additives (including, for example, defoamers and surfactants). In one example, the amount of the thermal layer components may be as follows: 0.3 g / m 2 Up to 0.7g / m 2 Color former, 0.6g / m 2 Up to 1.0g / m 2 Developer, 0.3g / m 2 Up to 0.7g / m 2 Absorbent pigment, 0.3g / m 2 Up to 0.7g / m 2 Adhesive and / or 0.3g / m 2 Up to 0.7g / m 2 additives.

[0057] The optional pre-coat layer of the paper-based surface material may include a pigment (such as calcined clay) and a binder (such as starch and / or styrene-butadiene latex). In one example, the pre-coat layer may include 4 g / m 2 Up to 8g / m 2 Pigment and / or 1g / m 2 Up to 3g / m 2 The pre-coat layer may have the effect of reducing the heat transfer from the heat-sensitive coating to the base paper. This may enable the formation of enhanced or high-resolution print content. The pre-coat layer may have the effect of smoothing the surface material. The smoothness of the surface material has a positive impact on printing, for example by providing better resolution. Therefore, the pre-coat layer may have a positive impact on the print quality.

[0058] The optional barrier layer (also referred to as the reverse barrier layer) may include PVA and kaolin. In one example, the barrier layer includes 0.3 to 0.7 g / m 2 PVA and / or 1.0 to 2.0 g / m 2 Kaolin.

[0059] Adhesives

[0060] As mentioned above, the pressure sensitive adhesive of the linerless wash-off label is sensitive to washing conditions. The pressure sensitive adhesive comprises a water-based acrylic emulsion polymer composition. The pressure sensitive adhesive may comprise a surfactant to achieve washability. The coating weight of the pressure sensitive adhesive may be 13 g / m 2 Up to 25g / m 2 (dry weight). To promote washability, it is preferred to reduce the coating weight as much as possible. In addition, low coating weight is also beneficial from the perspective of raw material usage. The pressure sensitive adhesive can be provided as a single layer or multiple layers.

[0061] Preferably, the pressure sensitive adhesive exhibits good anchoring to the paper-based face stock. This has the effect of preventing any adhesive residue from accumulating on the printer during label printing. Furthermore, importantly, when the wash-off label is exposed to washing conditions, the anchoring allows the adhesive to remain with the face stock without leaving any adhesive residue on the surface from which the label is detached. Furthermore, since the adhesive remains with the face stock under washing conditions, there is no significant contamination of the washing solution by the adhesive.

[0062] In one embodiment, the pressure sensitive adhesive is arranged to completely cover the adhesive receiving surface of the paper-based face material. In another embodiment, the pressure sensitive adhesive is arranged in at least two strips oriented in the machine direction, leaving a non-adhesive area between the strips. For example, the width of the adhesive strip in the transverse direction is 3 to 7 mm, such as 5 mm. The width of the non-adhesive area in the transverse direction can be 3 to 7 mm, such as 5 mm. When using a full coverage adhesive, the adhesive coating weight used can be lower than the case of the adhesive arranged in strips. In other words, when the adhesive is arranged in strips, a slightly higher coating weight may be required to obtain a sufficiently high adhesion.

[0063] Arranging the adhesive in machine direction oriented stripes, leaving non-adhesive areas between the stripes, may be referred to as pattern gluing. Pattern gluing may be preferred from a material usage perspective because less adhesive needs to be used when the adhesive is arranged in alternating stripes of adhesive and non-adhesive, and therefore less raw material is used. More importantly, the non-adhesive areas can improve the washability of the label because they provide a "pathway" for cleaning fluids / solutions to enter the underside of the label, which is the adhesive side between the facestock and the labeling surface beneath the facestock.

[0064] Method for producing linerless wash-off labels

[0065] The linerless wash-off labels disclosed herein are provided as part of a linerless label product roll that includes linerless wash-off labels.

[0066] A method for producing a linerless wash-off label roll for providing a linerless label product roll includes arranging a paper-based face stock or a carrier as a substrate and coating the substrate with a pressure-sensitive adhesive. The pressure-sensitive adhesive comprises a water-based acrylic emulsion polymer composition, and the pressure-sensitive adhesive is sensitive to washing conditions. The method also includes drying and / or curing the pressure-sensitive adhesive on the substrate. When the substrate is a carrier, the pressure-sensitive adhesive is transferred from the carrier to the paper-based face stock. The method also includes winding the paper-based face stock with the adhesive thereon into a roll of linerless wash-off label roll. The paper-based face stock includes a release layer, and in the final structure, the pressure-sensitive adhesive and the release layer are arranged on opposite sides of the paper-based face stock. The paper-based face stock includes a wet strength resin and has a water absorption of 10 to 30 g / m measured according to ISO standard 535 (contact time 60 seconds). 2 .

[0067] Linerless wash-off label product rolls are manufactured by machine direction slitting linerless wash-off label web stock.

[0068] Washability of linerless wash-off labels

[0069] As previously mentioned, the linerless label disclosed herein is a wash-off label that is removable (detachable) from the surface to which it is attached during subsequent washing. Washability is provided by an adhesive that is sensitive to washing conditions. In addition, the properties of the facestock discussed above also have an impact on washability.

[0070] The pressure sensitive adhesive of the linerless wash-off labels disclosed herein may have reduced adhesion under washing conditions. This means that under washing conditions, the adhesive properties such as tack and peel of the adhesive may be reduced. In fact, the tack and peel values ​​of the adhesive after washing may be zero or negligible. Therefore, the adhesive after being released by washing may not have any adhesive properties.

[0071] Washing conditions for releasing the linerless wash-off labels described herein include a temperature of at least 20°C and an aqueous wash solution. In one example, the washing conditions may include an elevated temperature. The elevated temperature of the wash solution may refer to a temperature above room temperature, such as at least 25°C. The temperature of the wash solution may be up to 90°C. Preferably, the temperature of the wash solution is as low as possible or close to room temperature from an energy-saving perspective.

[0072] In one example, the linerless wash-off labels disclosed herein can be released from the labeled surface when exposed to an aqueous wash solution at a temperature of at least 20°C.

[0073] In one example, the linerless wash-off labels disclosed herein can be released from the labeled surface when immersed in an aqueous washing solution having a temperature of at least 20°C.

[0074] In one example, the linerless wash-off labels disclosed herein can be released from the labeled surface when exposed to an aqueous wash solution under water pressure. The water pressure can be of the order of water pressures conventionally used in dishwashers, for example 1.3 to 8.3 bar.

[0075] In one example, the linerless wash-off labels disclosed herein can be released from the labeled surface when exposed to an aqueous wash solution at a temperature of 20° C. to 90° C. For example, the linerless wash-off labels can be released from the labeled surface when exposed to an aqueous wash solution at a temperature of 30° C., 40° C., 50° C., 60° C., or 65° C.

[0076] As already discussed, the adhesive properties (eg, tack and release) of the adhesive will preferably degrade when the label is exposed to washing conditions, and in fact, the adhesive may not have any adhesive properties after release by washing.

[0077] Tack refers to the holding power (adhesion) of an adhesive when in contact with a substrate. An adhesive with a high initial tack will quickly grab the substrate. An adhesive with a low initial tack will exhibit a low level of adhesion when applied. Tack can be measured according to the loop tack measurement of FINAT Test Method No. 9 (FTM9). The loop tack value of an adhesive is expressed as the force required to separate a loop of material in contact with a surface of a specific area at a specific speed.

[0078] Peel force (also known as peel adhesion) is a measure of the ability of an adhesive to wet a substrate surface and subsequently adhere to the substrate. Peel force can therefore quantify the durability of an adhesive's adhesion or ability to peel. Peel force is defined as the force required to remove an adhesive coating material from a test panel after dwelling for a certain period of time at a 90 or 180 degree angle and a specific speed. Peel adhesion therefore refers to the ultimate adhesion. Peel adhesion can be measured according to FINAT Test Method No. 1 or 2 (FTM 1, FTM2).

[0079] According to one embodiment, the adhesive of the linerless wash-off labels disclosed herein has an average tack on glass / HDPE / PET in the range of 1.5 to 10 N when measured according to FTM 9. After release from the labeled surface by washing, the adhesive of the linerless wash-off labels disclosed herein has an average tack on glass / HDPE / PET in the range of 0 to 1 N.

[0080] According to one embodiment, the adhesive of the linerless wash-off labels disclosed herein has an average peel force on glass / HDPE / PET in the range of 1.5 to 10 N when measured according to FTM 1 or FTM 2. After release from the labeled surface by washing, the adhesive of the linerless wash-off labels disclosed herein has an average peel force on glass / HDPE / PET in the range of 0 to 1 N.

[0081] Washability, i.e. the ability to release from a labeling surface under washing conditions, also depends on the nature of the substrate, i.e. the nature of the labeling surface. For example, the labels disclosed herein are more easily released from a HDPE (high density polyethylene) surface than, for example, from a PET (polyethylene terephthalate) or glass surface. Thus, a lower temperature is required for a label to release from a HDPE surface than from a PET or glass surface.

[0082] In addition, washing conditions also affect the releasability. For example, when immersion is used for releasability, a higher temperature may be required compared to conditions including water pressure.

[0083] From an energy efficiency perspective, it is beneficial to release the label from the labeling surface as quickly as possible. According to one embodiment, when exposed to an aqueous washing solution, the linerless wash-off labels disclosed herein can be released from the labeling surface in 90 seconds or less, such as in 70 seconds, 50 seconds, or 30 seconds.

[0084] In one example, the linerless wash-off label releases from the labeled surface in 90 seconds or less when exposed to an aqueous wash solution having a temperature of 40 to 65 degrees.

[0085] The aqueous washing solution can be pure water / boiled water, and can also contain an alkaline agent. Pure water or boiled water refers to water that does not contain any additional ingredients. For example, pure water can refer to tap water. Pure water does not have to be purified water, but can be purified by, for example, distillation or deionization. The alkaline agent can be, for example, NaOH, KOH, sodium carbonate, dishwashing liquid, alkaline detergent, or any combination thereof. When the washing solution contains an alkaline agent, the washing conditions are alkaline. Alkaline washing conditions can typically contain about 0.5-10% or 1-4% (by weight) of the alkaline agent. For example, the washing solution can contain about 2% (by weight) of the alkaline agent.

[0086] When pure water without alkaline agents is used as the washing solution, it may not be necessary to include a separate rinsing step after the washing step responsible for the detachment of the label. However, when alkaline washing conditions are used, a rinsing step using pure water is required to rinse off any alkaline agents that may remain.

[0087] Example

[0088] Examples 1-3

[0089] For Examples 1-3, a paper-based face stock having the following structure was used:

[0090] 1) Coating weight is 0.5-1.0g / m 2 Silicone release layer,

[0091] 2) A heat-sensitive layer comprising

[0092] - leuco dyes as couplers,

[0093] - Phenol-free developer,

[0094] - absorbent pigments,

[0095] - binder,

[0096] 3) a pre-coat layer comprising calcined clay as a pigment and a binder,

[0097] 4) Base paper, comprising

[0098] -About 60g / m 2 fiber,

[0099] - Filling with pigment,

[0100] - binder,

[0101] - Additives including wet strength resins,

[0102] 5) A reverse barrier layer comprising PVA and kaolin.

[0103] The water absorption of the base paper is 22.5 g / m when measured from the heat-sensitive layer side. 2 , when measured from the reverse side: 21.0g / m 2 The water absorption is measured according to ISO standard 535 with a contact time of 60 seconds. The conditioning of the test specimens is carried out under the standard conditions specified in ISO standard 187.

[0104] The linerless wash-off labels of Examples 1-3 comprise a pressure sensitive adhesive comprising a water-based acrylic emulsion polymer composition disposed adjacent to the reverse barrier layer of the facestock.

[0105] Exemplary labels 1-3 have a length (machine direction) of 15 cm and a width (cross direction) of 5.8 cm (58 mm).

[0106] Example 1 is a linerless wash-off label in which the pressure sensitive adhesive is arranged in a 5-5-5 pattern, wherein the width of the continuous adhesive strip in the machine direction is 5 mm and the width of the non-adhesive area between the adhesive strips is 5 mm. The adhesive properties of the label are as follows: the average adhesion on glass is 6.04 N measured according to FTM 9; the average adhesion on HDPE is 2.15 N measured according to FTM 9; the average adhesion on PET is 3.32 N measured according to FTM 9; the average peel force on glass is 3.52 N measured according to FTM 1 or FTM 2; the average peel force on PET is 2.68 N measured according to FTM 1 or FTM 2; the average peel force on HDPE is 1.91 N measured according to FTM 1 or FTM 2.

[0107] Example 2 is a linerless wash-off label with the pressure sensitive adhesive arranged in a 3-3-3 pattern with a machine direction continuous adhesive stripe of 3 mm width and a non-adhesive area of ​​3 mm width between the adhesive stripes.

[0108] Example 3 is a linerless wash-off label in which the pressure sensitive adhesive is arranged in a 5-7-5 pattern, wherein the width of the continuous adhesive strip in the machine direction is 5 mm and the width of the non-adhesive area between the adhesive strips is 7 mm. The adhesive properties of the label are as follows: the average adhesion on glass is 4.87 N according to FTM 9; the average adhesion on HDPE is 3.20 N according to FTM 9; the average adhesion on PET is 2.84 N according to FTM 9; the average peel force on glass is 3.06 N according to FTM 1 or FTM 2; the average peel force on PET is 2.55 N according to FTM 1 or FTM 2; the average peel force on HDPE is 2.08 N according to FTM 1 or FTM 2.

[0109] The washability of the label was studied by immersing the labeled item in pure water in a beaker. The item was a PP (polypropylene) container. The water temperature was 63° C. The time required for the label to completely detach was measured for three parallel samples, as shown in Table 1 below.

[0110] Table 1.

[0111] time time time Example 1 32 seconds 36 seconds 27 seconds Example 2 29 seconds 49 seconds 33 seconds Example 3 94 seconds 48 seconds 78 seconds

[0112] Examples 1-3 demonstrate that very good wash times in pure water can be achieved using a hydrophilic paper-based facestock and a pressure sensitive adhesive comprising a water-based acrylic emulsion polymer composition arranged in a pattern of adhesive stripes and non-adhesive areas therebetween.

[0113] Example 4

[0114] For the labels of Example 4, the paper-based facestock had a similar construction as used in Examples 1-3, except that no release layer was present.

[0115] The linerless label of Example 4 has a pressure sensitive adhesive comprising a water-based acrylic emulsion polymer composition disposed adjacent to the reverse barrier layer of the facestock. The side of the facestock that receives the adhesive is completely covered with the adhesive. The coating weight of the adhesive is 16-17 g / m 2 The length (machine direction) of the label is 4 cm and the width (cross direction) is 2.5 cm.

[0116] Three labels were attached to bottles made of HDPE and the washability of the labels was studied by immersing the labeled bottles in pure water in a beaker. The water was stirred with a magnetic stirrer. The labels were attached in different positions, one label near the top of the bottle, another label near the bottom of the bottle, and the third label between the first two labels. The water temperature was 20°C, 30°C, or 40°C. The time required for each label to completely detach was measured.

[0117] In water at a temperature of 20°C, the label takes about 2.5 minutes to about 6 minutes to detach. Similarly, at a temperature of 30 degrees, the detachment time varies from about 2.5 minutes to about 6 minutes. In water at a temperature of 40 degrees, the detachment time is significantly shorter, typically ranging from about 50 seconds to about 90 seconds. The placement of the label has some effect on the time required for detachment, but the effect is not significant.

[0118] Example 4 shows that the label can be detached in pure water even at low temperatures. If very fast detachment is required, high temperatures are preferred, for example about 40°C.

Claims

1. A linerless wash-off label (100) comprising a paper-based face material (101, 201) and a pressure-sensitive adhesive (102), wherein The paper-based surface material (101, 201) comprises a base paper (206) and a release layer (203), wherein the release layer (203) and the pressure-sensitive adhesive (102) are arranged on opposite sides of the base paper (206). The pressure sensitive adhesive (102) comprises a water-based acrylic emulsion polymer composition, The pressure sensitive adhesive (102) is sensitive to washing conditions, as well as The base paper (206) comprises a wet strength resin and has a water absorption of 10 to 30 g / m2 measured according to ISO standard 535 (contact time 60 seconds). 2 .

2. The linerless wash-off label (100) according to claim 1, wherein: The pressure sensitive adhesive (102) is arranged in at least two continuous strips in the machine direction, leaving non-adhesive areas between the strips.

3. The linerless wash-off label (100) according to claim 1, wherein: The pressure sensitive adhesive (102) is arranged to completely cover one side of the paper-based facestock (101, 201).

4. The linerless wash-off label (100) according to any one of the preceding claims, wherein: The pressure sensitive adhesive (102) includes a surfactant.

5. The linerless wash-off label (100) according to any one of the preceding claims, wherein: The paper-based surface material (101, 201) is a surface material capable of direct thermal printing.

6. The linerless wash-off label (100) according to any one of the preceding claims, wherein: The coating weight of the pressure sensitive adhesive (102) is 13-25 g / m 2 .

7. The linerless wash-off label (100) according to any one of the preceding claims, wherein: The coating weight of the release coating forming the release layer (203) is 0.5-1.0 g / m 2 .

8. The linerless wash-off label (100) according to any one of the preceding claims, wherein: The linerless wash-off label (100) is capable of being released from the labeled surface when exposed to an aqueous washing solution at a temperature of at least 20°C.

9. The linerless wash-off label (100) according to any one of the preceding claims, wherein: The linerless wash-off label (100) is capable of being released from the labeled surface when immersed in an aqueous washing solution having a temperature of at least 20°C.

10. The linerless wash-off label (100) according to any one of the preceding claims, wherein: The linerless wash-off label (100) is capable of being released from the labeled surface when exposed to an aqueous washing solution at elevated temperatures.

11. The linerless wash-off label (100) according to any one of the preceding claims, wherein: The linerless wash-off label (100) is capable of being released from the labeled surface when exposed to an aqueous washing solution under water pressure.

12. The linerless wash-off label (100) according to any one of the preceding claims, wherein: The linerless wash-off label (100) is capable of releasing from the labeled surface in 90 seconds or less when exposed to an aqueous washing solution.

13. A linerless label product roll comprising the linerless wash-off label (100) according to any one of claims 1 to 12.

14. A labeled article comprising an article and the linerless wash-off label (100) according to any one of claims 1 to 12, wherein the linerless wash-off label (100) is adhered to a surface of the article by a pressure-sensitive adhesive (102) of the linerless wash-off label.

15. The labeled article of claim 14, wherein: The object is a plastic object, a glass object or a metal object.

16. A labeled article according to claim 14 or 15, wherein: The article is a container including a lid, one end of the linerless wash-off label is affixed to the lid, and the other end of the linerless wash-off label is affixed to the container.

17. Use of the linerless wash-off label (100) according to any one of claims 1 to 12 for labelling articles.

18. A method of manufacturing a linerless wash-off label web for providing a linerless label product roll as claimed in claim 13, the method comprising: - Arranging a paper-based surface material (101, 201) or a carrier as a substrate, - coating the substrate with a pressure-sensitive adhesive (102), - drying and / or curing the pressure sensitive adhesive (102) on the substrate, - in the case where the substrate is a carrier, transferring the pressure sensitive adhesive (102) from the carrier to the paper-based surface material (101, 201), and - rolling up the paper-based surface material (101, 201) with the adhesive (102) thereon into a roll of linerless wash-off label roll, The paper-based surface material (101, 201) comprises base paper (206) and a release layer (203). in, The pressure-sensitive adhesive (102) and the release layer (203) are arranged on opposite sides of the base paper (206), The pressure sensitive adhesive (102) comprises a water-based acrylic emulsion polymer composition, The pressure sensitive adhesive (102) is sensitive to washing conditions, as well as The base paper (206) comprises a wet strength resin and has a water absorption of 10 to 30 g / m2 measured according to ISO standard 535 (contact time 60 seconds). 2 .

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