Powdery pigment preparations for dyeing films
The invention relates to a powdery pigment preparation containing a pigment which is dispersed in an acrylate resin and which is characterized in that the acrylate resin has an average molecular mass Mw ranging from 40000 to 80000 g/mol and is a copolymer comprised of 50 to 65 mol % ethyl methacrylate, of 30 to 45 mol % butyl methacrylate, and of 0.5 to 5 mol % methacrylic acid. The powdery pigment preparation can be used for dyeing films, particularly those made of polymethyl methacrylate. The films do not have any specks nor holes.
1. A colored polymethyl methacrylate film comprising polymethyl methacrylate film colored by a pigment composition, wherein the pigment composition comprises a pigment in dispersion in an acrylate resin, wherein the acrylate resin has an average molar mass Mw of between 40 000 and 80 000 g/mol and is a copolymer of from 50 to 65 mol % ethyl methacrylate, from 30 to 45 mol % butyl methacrylate, and from 0.5 to 5 mol % methacrylic acid, wherein colored polymethyl methacrylate film has a thickness of between 5 to 1000 μm.
2. A colored polymethyl methacrylate film as claimed in claim 1 , wherein the acrylate resin has an average molar mass Mw between 50 000 and 70 000 g/mol.
3. A colored polymethyl methacrylate film as claimed in claim 1 , wherein the acrylate resin is composed of from 55 to 60 mol % ethyl methacrylate, from 35 to 40 mol % butyl methacrylate, and from 1 to 4 mol % methacrylic acid.
4. A colored polymethyl methacrylate film as claimed in claim 1 , wherein the butyl methacrylate is n-butyl methacrylate.
5. A colored polymethyl methacrylate film as claimed in claim 1 , wherein the weight ratio between the pigment and the acrylate resin is from 70:30 to 30:70.
6. A colored polymethyl methacrylate film as claimed in claim 1 , wherein the pigment is selected from the group consisting of a monoazo, disazo, laked azo pigment, azo condensation pigment, benzimidazolone, naphthol, isoindolinone, isoindoline, phthalocyanine, quinacridone, anthanthrone, perylene, perinone, thioindigo, thiazineindigo quinophthalone, dioxazine, diketopyrrolopyrrole pigment and carbon black.
7. A colored polymethyl methacrylate film as claimed in claim 1 , wherein the pigment is a nickel titanate, chromium titanate, iron oxide, ultramarine, chromium oxide or titanium dioxide.
8. A colored polymethyl methacrylate film as claimed in claim 1 , wherein the pigment composition further comprises
a) from 30 to 70% by weight of the pigment;
b) from 70 to 30% by weight of the acrylate resin,
c) from 0 to 8% by weight of a lubricant, and
d) from 0 to 10% by weight of additives, the sum of all components being 100% by weight.
9. A colored polymethyl methacrylate film as claimed in claim 1 , wherein the pigment composition further comprises:
a) from 45 to 55% by weight of the pigment;
b) from 55 to 45% by weight of the acrylate resin,
c) from 2 to 4% by weight of a lubricant, and
d) from 0 to 1% by weight, of at least one additive, the sum of all components being 100% by weight.
10. A method for coloring the colored polymethyl methacrylate film as claimed in claim 1 , comprising the step of adding the pigment composition to the polymethyl methacrylate during the production of the polymethyl methacrylate film.