Brittle acrylic films and forgery prevention labels comprising the same

1 : A forgery prevention label, comprising:

a polyalkyl(meth)acrylate film, wherein the polyalkyl(meth)acrylate film comprises:

from 30.0 wt.-% to 92.5 wt.-% of a polyalkyl(meth)acrylate:

from 2.5 wt.-% to 40.0 wt.-% of one or several impact modifiers;

from 5.0 wt.-% to 40.0 wt.-% of one or several inorganic fillers;

from 0.0 wt.-% to 5.0 wt.-% of one or several UV-absorbers; and

from 0.0 wt.-% to 5.0 wt.-% of one or several UV-stabilizers, based on the weight of the polyalkyl(meth)acrylate film;

wherein the cumulative content of the polyalkyl(meth)acrylate and the impact modifier is from 60.0 wt.-% to 95.0 wt.-%, based on the weight of the polyalkyl(meth)acrylate film; and

the content, in wt.-%, of the one or several impact modifiers n im in the polyalkyl(meth)acrylate film is described by the following relationship:

0.5* n f <n im <n f

n f being the content, in wt.-%, of the one or several inorganic fillers in the polyalkyl(meth)acrylate film.

2 : The forgery prevention label according to claim 1 , wherein the polyalkyl(meth)acrylate has an average molar weight Mw of from 50 000 g/mol to 300 000 g/mol and is obtainable by polymerization of a composition whose polymerizable constituents comprise, based on the weight of the polymerisable 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 C 1 -C 4 alcohol, and

(c) from 0.0 wt.-% to 10.0 wt.-% of at least one further monomer copolymerizable with the monomers (a) and (b).

3 : The forge prevention label according to claim 1 , wherein the polyalkyl(meth)acrylate film has

a thickness of from 15 μm to 120 μm,

an elongation at break, measured according to ASTM D1004-13, of from 0.5% to 15%, and

an initial tear resistance, measured according to ASTM D1004-13, of from 0.1 N to 30.0 N.

4 : The forgery prevention label according to claim 1 , wherein the polyalkyl(meth)acrylate film has a resistance to tear propagation, measured according to ASTM D1938-14, of from 0.01 N to 1.00 N.

5 : The forgery prevention label according to claim 1 , wherein the content, in wt.-%, of the one or several impact modifiers n im in the polyalkyl(meth)acrylate film is described by the following relationship:

0.6* n f <n im <0.8* n f

n f being the content, in wt.-%, of one or several inorganic fillers in the polyalkyl(meth)acrylate film.

6 : The forgery prevention label according to claim 1 , wherein the one or several inorganic fillers are selected from the group consisting of titanium dioxide, silica, barium sulphate, aluminium trihydroxide and calcium carbonate.

7 : The forgery prevention label according to claim 1 , wherein the polyalkyl(meth)acrylate has an average molar weight Mw of from 80 000 g/mol to 200 000 g/mol and is obtainable by polymerization of a composition whose polymerizable constituents comprise, based on the weight of the polymerisable composition:

(a) from 80.0 wt.-% to 99.0 wt.-% of methyl methacrylate, and

(b) from 1.0 wt.-% to 20.0 wt.-% of an acrylic acid ester of a C 1 -C 4 alcohol.

8 : The forgery prevention label according to claim 1 , wherein the forgery prevention label comprises at least the following layers in the order stated:

a) a layer consisting of the polyalkyl(meth)acrylate film;

b) an adhesive layer;

c) a release coating layer; and

d) a support layer;

and/or the forgery prevention label has a thickness of between 80 μm and 300 μm.

9 : A laminate for manufacturing of the prevention label according to claim 1 , the laminate comprising at least the following layers:

a) a liner layer; and

b) a layer consisting of the polyalkyl(meth)acrylate film.

10 : The laminate according to claim 9 , wherein the liner layer substantially consists of a polymeric material selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate and mixtures thereof.

11 : A process for manufacturing of the laminate as claimed in claim 9 , the process comprising:

i) preparing the polyalkyl(meth)acrylate film using an extruder, wherein the polyalkyl(meth)acrylate film is obtained; and

ii) binding the liner layer to the polyalkyl(meth)acrylate film from step i) downstream of the extruder.

12 : The process according to claim 11 , wherein the laminate obtained in step ii) is passed between a plurality of rolls, wherein at least a roll facing towards the side of the polyalkyl(meth)acrylate film is a cooled roll.

13 : A process for manufacturing of the forgery prevention label according to claim 1 , the process comprising:

i) preparing the polyalkyl(meth)acrylate film using an extruder; and

ii) binding a liner layer to the polyalkyl(meth)acrylate film from step 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 step ii), wherein a label stock is obtained:

iv) kiss cutting the label stock obtained in step iii) and removing a resulting waste matrix, wherein a plurality of individual self-adhesive forgery prevention labels on a support layer is obtained.

14 : A method, comprising:

manufacturing of chip cards, documents, forgery prevention labels, other labels or price tags using the forgery prevention label according to claim 1 .

15 : The forgery prevention label according to claim 8 , wherein the layer consisting of the polyalkyl(meth)acylate film has a thickness of from 40 μm to 60 μm, the adhesive layer has a thickness of from 20 μm to 30 μm, the release coating layer has a thickness of from 0.6 μm to 0.8 μm, and the support layer has a thickness of from 30 μm to 50 μm.

16 : The laminate according to claim 9 , wherein the liner layer has initial tear resistance, measured according to ASTM D1004-13, of from 50 N to 500 N.

17 : The laminate according to claim 10 , wherein the polymeric material is a biaxially oriented polypropylene or a biaxially oriented polyethylene terephthalate.