US-12617975-B2 - Face for a direct thermal linerless label and a direct thermal linerless label

US12617975B2US 12617975 B2US12617975 B2US 12617975B2US-12617975-B2

Abstract

The specification relates to a face ( 100, 200 ) for a direct thermal linerless label. The face ( 100, 200 ) comprises a release layer ( 101, 201 ), a thermal layer ( 102, 202 ), a pre-coat layer ( 103, 203 ), a base paper ( 104, 204 ), and a barrier layer ( 105, 205 ). The base paper ( 104, 204 ) has a grammage of from 50 to 90 g/m 2 and the barrier layer ( 105, 205 ) has a coat weight (dry) of from 0.5 to 3.5 g/m 2 . Further, a direct thermal linerless label ( 210 ), a linerless label product roll comprising direct thermal linerless labels and a labelled item are provided. Also, use of the direct thermal linerless label ( 210 ) for labelling an item as well as a method of manufacturing a linerless label web for providing the linerless product roll are provided.

Inventors

Juha KIVIMÄKI
Magdalena RABSKA
Katarzyna Wojtuś

Assignees

UPM RAFLATAC OY

Dates

Publication Date: 20260505
Application Date: 20241031
Priority Date: 20231103

Claims (9)

1 . A face for a direct thermal linerless label, wherein the face comprises: a release layer; a thermal layer; a pre-coat layer; a base paper; and a barrier layer, wherein the base paper has a grammage of from 50 to 90 g/m 2 and the barrier layer has a coat weight (dry) of from 0.5 to 3.5 g/m 2 ; and wherein the barrier layer comprises PVA and kaolin.
2 . A direct thermal linerless label, comprising a pressure sensitive adhesive and the face according to claim 1 , wherein the release layer and the pressure sensitive adhesive are arranged on opposite sides of the base paper.
3 . The direct thermal linerless label according to claim 2 , wherein the pressure sensitive adhesive is a water-based adhesive.
4 . The direct thermal linerless label according to claim 2 , wherein the pressure sensitive adhesive is a hot-melt adhesive.
5 . The direct thermal linerless label according to claim 2 , wherein a coat weight of the pressure sensitive adhesive is from 12 to 25 g/m 2 .
6 . A linerless label product roll comprising the direct thermal linerless labels according to claim 2 .
7 . A labelled item comprising an item and a direct thermal linerless label according to claim 2 , wherein the direct thermal linerless label is attached to a surface of the item via the pressure sensitive adhesive of the direct thermal linerless label.
8 . A method of using the direct thermal linerless label according to claim 2 , comprising labelling an item with the direct thermal linerless label.
9 . A method of manufacturing a linerless label web for providing the linerless label product roll according to claim 6 , the method comprising: arranging a face or a carrier as a substrate; coating the substrate with pressure sensitive adhesive; drying and/or curing the pressure sensitive adhesive on the substrate; in case of the substrate being a carrier, transferring the pressure sensitive adhesive from the carrier to a face; and winding the face with the adhesive thereon into a roll of linerless label web.

Description

RELATED APPLICATIONS This application claims priority to Finnish Patent Application No. 20236229, filed on Nov. 3, 2023, and Finnish Patent Application No. 20245484, filed Apr. 16, 2024, each of which is incorporated by reference herein in its entirety. TECHNICAL FIELD The specification relates to a face for a direct thermal linerless label. Further, the specification relates to a direct thermal linerless label, a linerless label product roll comprising direct thermal linerless labels and a labelled item. Still further, the specification relates to use of the direct thermal linerless label for labelling an item as well as to a method of manufacturing a linerless label web for providing the linerless product roll. BACKGROUND Conventionally water-based adhesives are particularly challenging with direct thermal linerless face materials (papers). Direct coating of the water-based adhesive causes adhesive wetting, which changes viscoelastic properties of the face paper, consequently causing diverse problems in the manufacturing phase as well as in label application phase at the end user site. Changes in the viscoelastic properties refer to decreased tensile strength level and increased elongation in machine direction (MD) during the adhesive coating and drying/curing process. The problems caused by the changes include for example severe curling of the label taking place after direct thermal printing and cutting of the labels, dimensional instability after guillotine cutting, as well as web breaks with lower basis weight face papers. Furthermore, adhesives when used with paper-based direct thermal linerless face are prone to migration of the adhesive components through the face. Migration of the adhesive components into the thermal layer of the face decreases the sensitivity level of the thermal layer. This worsens the direct thermal printability properties of the face. Thus, there is need for new face materials that would alleviate the above discussed challenges. SUMMARY The face disclosed herein has improved properties that have positive impact on label face performance ranging from the label web manufacturing to the dispensing of the labels. Wetting of the face in adhesive coating process with water-based adhesive is prevented or diminished, thereby providing improved tension control and better dimensional stability. Further, the face disclosed herein provides improved flatness, i.e., lower curling level of the labels, thereby enabling more efficient printing process and easier dispensing, particularly with automatic dispensers. Still further, the face shows improved stability of the thermal layer, thereby ensuring good printing quality even after aging. According to an embodiment, face for a direct thermal linerless label is provided. The face comprises a release layer, a thermal layer, a pre-coat layer, a base paper, and a barrier layer. The base paper has a grammage of from 50 to 90 g/m2 and the barrier layer has a coat weight (dry) of from 0.5 to 3.5 g/m2. According to another embodiment, a direct thermal linerless label is provided. The direct thermal linerless label comprises pressure sensitive adhesive and a face comprising a release layer, a thermal layer, a pre-coat layer, a base paper, and a barrier layer, the base paper having a grammage of from 50 to 90 g/m2. The release layer and the pressure sensitive adhesive are arranged on opposite sides of the base paper. In an embodiment, a linerless label product roll comprising the direct thermal linerless labels disclosed herein is provided. Further, in an embodiment, a labelled item comprising an item and a direct thermal linerless label as disclosed herein is provided. The direct thermal linerless label is attached to a surface of the item via the pressure sensitive adhesive of the direct thermal linerless label. In an embodiment, use of the direct thermal linerless label as disclosed herein for labelling an item is provided. According to yet another embodiment, a method of manufacturing a linerless label web for providing the linerless label product roll is provided. The method comprises arranging a face or a carrier as a substrate,coating the substrate with pressure sensitive adhesive,drying and/or curing the pressure sensitive adhesive on the substrate,in case of the substrate being a carrier, transferring the pressure sensitive adhesive from the carrier to a face, andwinding the face with the adhesive thereon into a roll of linerless label web. The face comprises a release layer, a thermal layer, a pre-coat layer, a base paper, and a barrier layer. The base paper has a grammage of from 50 to 90 g/m2 and the barrier layer has a coat weight (dry) of from 0.5 to 3.5 g/m2. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates, by way of an example, a cross-sectional view of a direct thermal linerless face, and FIG. 2 illustrates, by way of an example, a cross-sectional view of a direct thermal linerless label. The figures are schematic and are not on par