Laser engravable labels

Patent metadata

Field	Value
Publication number	US-2023391057-A1
Application number	US-202118249483-A
Country	US
Kind code	A1
Filing date	Oct 21, 2021
Priority date	Oct 26, 2020
Publication date	Dec 7, 2023
Grant date	—

Abstract

Coextruded acrylic foils made from impact-modified polyalkyl (meth)acrylates and laser engravable labels containing these foils. The coextruded acrylic foils are designed for labelling by a laser and contain a contrast layer having at least one inorganic filler and an engraving layer arranged on the contrast layer and having at least one colourant.

First claim

1 : A coextruded acrylic foil comprising a layer A and a layer B, wherein
the layer A comprises:
from 30.0 wt.-% to 98.5 wt.-% an acrylic polymer A;
from 1.0 wt.-% to 40.0 wt.-% of an impact modifier;
from 0.5 wt.-% to 20.0 wt.-% of a colourant;
from 0.0 wt.-% to 10.0 wt.-% of an inorganic filler;
from 0.0 wt.-% to 5.0 wt.-% of a UV absorber;
and from 0.0 wt.-% to 5.0 wt.-% of a UV stabilizer, based on the weight of the layer A;
wherein a cumulative content of the acrylic polymer A and the impact modifier in the layer A is from 60.0 wt. % to 99.5 wt.-%, based on the weight of the layer A; and the layer B comprises:
from 30.0 wt.-% to 92.5 wt.-% of an acrylic polymer B;
from 2.5 wt.-% to 35.0 wt.-% of an impact modifier;
from 5.0 wt.-% to 35.0 wt.-% of an inorganic filler;
from 0.0 wt.-% to 5.0 wt.-% of a UV absorber; and
from 0.0 wt.-% to 5.0 wt.-% of a UV stabilizer, based on the weight of the layer B;
wherein cumulative content of the acrylic polymer B and the impact modifier in the layer B is from 60.0 wt.-% to 95.0 wt.-%, based on the weight of the layer B.

2 : The coextruded acrylic foil according to claim 1 , wherein the content, in wt.-%, of the impact modifier n imA in the layer A is described by the following relationship:
( n fA +n pA )≤ n imA ≤7*( n fA +n pA )
n fA being the content, in wt.-%, of the inorganic filler and n pA being the content, in wt.-%, of the colourant in the layer A; and the content, in wt.-%, of the impact modifier n imB in the layer B being satisfied by the following relationship:
0.25* n fB ≤n imB ≤2* n fB

n fB being the content, in wt.-%, of the inorganic filler in the layer B.

3 : The coextruded acrylic foil according to claim 1 , wherein a glass transition temperature of the acrylic polymer A, the acrylic polymer B, or both is at least 110° C.

4 : The coextruded acrylic foil according to claim 1 , wherein the acrylic polymer A, the acrylic polymer B, or both are independently a poly(meth)acrylimide comprising at least 50 wt.-%, based on the weight of the poly(meth)acrylimide, of repeating units of Formula (I):

wherein R 1 and R 2 are independently selected from hydrogen and a methyl group, and R 3 is hydrogen or a C 1 -C 4 -alkyl group.

5 : The coextruded acrylic foil according to claim 1 , wherein the acrylic polymer A, the acrylic polymer B, or both independently have an average molar weight Mw of from 50,000 g/mol to 300,000 g/mol, determined by GPC against PMMA calibration standards and THF as an eluent, and are obtained by polymerization of a composition whose polymerizable constituents comprise, based on the weight of the polymerizable composition:
(a) from 50.0 wt.-% to 99.9 wt.-% of methyl methacrylate, (b) from 0.1 wt.-% to 50.0 wt.-% of an acrylic acid ester of a C1-C4 alcohol, (c) from 0.0 wt.-% to 10.0 wt.-% of at least one further monomer copolymerizable with the monomers (a) and (b).

6 : The coextruded acrylic foil according to claim 1 , wherein the inorganic filler in the layers A and B are independently selected from zirconium dioxide, titanium dioxide, silica, barium sulphate, aluminium trihydroxide, mica, zinc oxide, zinc sulphide, clay, muscovite and calcium carbonate.

7 : The coextruded acrylic foil according to claim 1 , wherein the colourant is a pigment or a dye.

8 : The coextruded acrylic foil according to claim 1 , wherein:
the foil has a thickness of from 10 μm to 200 μm; the layer A has a thickness d A of from 5 μm to 100 μm; and the layer B has a thickness d B of from 5 μm to 100 μm.

9 : The coextruded acrylic foil according to claim 1 , wherein the foil has at least one selected from the group consisting of:
elongation at break, measured according to DIN EN ISO 527-3 (2019), of from 0.5% to 15%; initial tear resistance, measured according to ASTM D1004 (2013), of from 0.1 N to 30.0 N; and resistance to tear propagation, measured according to ASTM D1938 (2019), of from 0.01 N to 1.00 N.

10 : A laser engravable label, wherein the laser engravable label comprises at least the following layers in the following order:
a) a layer consisting of the coextruded acrylic foil according to claim 1 ; b) an adhesive layer; c) a release coating layer; d) a support layer; wherein the laser engravable label has a thickness of between 80 μm and 300 μm.

11 : A laminate comprising at least the following layers:
a) a liner layer having initial tear resistance, measured according to ASTM D1004-13, of from 50 N to 500 N; and b) a layer consisting of the coextruded acrylic foil according to claim 1 .

12 : The laminate according to claim 11 , wherein the liner layer substantially consists of a polymeric material selected from the group consisting of polyethylene, polypropylene, polyimide, polyethylene terephthalate and polyethylene naphthalate.

13 : A process for manufacturing a laminate comprising
(a) a liner layer having initial tear resistance, measured according to ASTM D 1004-13, of from 50 N to 500 N, and (b) a layer consisting of the coextruded acrylic foil according to claim 1 , the process comprising: i) preparing a coextruded acrylic foil according to claim 1 using an extruder; ii) passing the coextruded acrylic foil obtained in the preparing i) between a plurality of rolls, wherein at least one roll is a cooled roll; and iii) binding a liner layer to the coextruded acrylic foil from the passing ii), to obtain a laminate.

14 : A process for manufacturing self-adhesive laser engravable labels, the process comprising:
i) preparing a coextruded acrylic foil according to claim 1 using an extruder; ii) optionally, binding a liner layer to the coextruded acrylic foil from the preparing i) downstream of the extruder, wherein a laminate is obtained; iii) binding an adhesive layer, optionally, a release coating layer and a support layer onto the laminate from the optional binding ii) or the coextruded acrylic foil from the preparing i), wherein a label stock is obtained; and iv) kiss cutting the label stock obtained in the binding iii) and removing the resulting waste matrix, wherein a plurality of individual self-adhesive laser engravable labels on a support layer is obtained.

15 : The coextruded acrylic foil according to claim 1 , wherein the coextruded acrylic foil is suitable for manufacturing of a laser engravable label.

16 : The coextruded acrylic foil according to claim 1 , wherein the acrylic polymer A, the acrylic polymer B, or both are independently a poly(meth)acrylimide comprising a 60 wt.-%, based on the weight of the poly(meth)acrylimide, of repeating units of Formula (I):

wherein R 1 and R 2 are independently selected from a methyl group, and R 3 is a methyl group.

17 : The coextruded acrylic foil according to claim 1 , wherein the inorganic filler in the layers A and B are independently selected from the group consisting of zirconium dioxide, rutile-type titanium dioxide, fused silica, barium sulphate, aluminium trihydroxide, mica, zinc oxide, zinc sulphide, clay, muscovite and calcium carbonate.

18 : The coextruded acrylic foil according claim 1 , wherein the colorant comprises at least one pigment selected from the group consisting of carbon black, iron oxide, cobalt oxide, aniline black and perylene black, Pigment Red 48:2, Pigment

Assignees

• Roeehm Gmbh
• Roehm Gmbh

Inventors

• Struwe Kim
• Parusel Markus
• Seyoum Ghirmay
• Guénanten Claude
• Haering Helmut

Classifications

• B32B27/08 Primary

  of synthetic resin · CPC title

• B32B27/308 Primary

  comprising acrylic (co)polymers · CPC title

• B32B27/20

  using fillers, pigments, thixotroping agents · CPC title

• B32B7/02

  Physical, chemical or physicochemical properties · CPC title

• B32B7/12 Primary

  using interposed adhesives or interposed materials with bonding properties · CPC title