Multilayer effect pigments from biodegradable polymers

Abstract

The present invention relates to effect pigments and multilayer films from two or more biodegradable polymer layers having different refraction indices and in alternating order, a method for producing them, and to their use, inter alia, in cosmetic products, rinse-off products, packaging materials, decorative films, paints, printing inks and plastics.

Description

[0001] Multilayer effect pigments made from biodegradable polymers

[0002] The present invention relates to effect pigments and multilayer films made of two or more biodegradable polymer layers with different refractive indices and in alternating sequence, to processes for their production, and to their use, inter alia, in cosmetic products, rinse-off products, packaging materials, decorative films, paints, printing inks and plastics.

[0003] Conventional decorative or effect films often consist of uniaxially or biaxially stretched polyester films, which consist of alternating polymer layers such as PET (polyethylene terephthalate) and PBT (polybutylene terephthalate). The stretching of the multilayer films results in a different degree of orientation and therefore a different degree of refraction in the alternating layers, resulting in an angle-dependent color effect. By additionally coloring the films, e.g. with solvent dyes, an individual color tone can be achieved. Optionally, a barrier effect in combination with a reflective effect can be achieved by applying a metal layer, usually aluminum. Films of this type are used as packaging materials, e.g. for gifts, flowers and food. Derived from such films, for example,Glitter particles are produced by grinding, cutting or punching and are used in cosmetics, rinse-off products such as shower gel or in toys.

[0004] The ordered alignment of polymer chains in a stretching process necessitates the use of polyesters with an aromatic dicarboxylic acid, particularly terephthalic acid, as the monomer component. However, these materials are not biodegradable and are currently not economically viable from renewable raw material sources.

[0005] The object of the present invention is therefore to produce biodegradable effect pigments and multilayer films from sustainable raw materials (i.e. consisting of a proportion of more than >50% bio-based raw materials), which consist of biodegradable polymers, but without contributing to the further increase of microplastics in the environment, which preferably do not require metallic or inorganic layers, and which can be produced in a simple and cost-effective process from commercially available starting materials in a wide variety of colors.

[0006] This object is achieved according to the invention by effect pigments and multilayer films as described and claimed in the present application. In particular, it has surprisingly been found that this object can be achieved by obtaining pigments from a multilayer film which consists of a large number, e.g. 64 to 256, alternating, optically active individual layers of only two polymers with different refractive indices, which are commercially available and preferably obtainable from natural sources and are biodegradable. The polymer layers can be extruded, cut and stacked simultaneously, do not require subsequent stretching, and display very good adhesion without further auxiliaries and, depending on the layer thickness and the refractive index, a metallic-looking color effect produced by interference.These multilayer films can be reduced into particles of suitable size, for example by grinding, cutting or punching, which can then be used as effect pigments.

[0007] Furthermore, it was surprisingly found that a material combination of the two commercially available and biodegradable polymers polylactide (in particular as D / L copolymer) and PBAT (polybutylene adipate terephthalate), in particular as a random copolymer, is particularly well suited for use in the effect pigments and multilayer films according to the invention.

[0008] US6299979 describes a polymeric color effect pigment containing a plurality of layers of thermoplastic organic materials with different refractive indices. However, biodegradable materials are not mentioned therein. US 2007 / 014977 A1 describes multilayer, iridescent films consisting of alternating, biodegradable polylactic acid layers and non-biodegradable polyterephthalate layers. The films are produced by co-extrusion of the two polymers and then preferably stretched to increase the refractive index difference and achieve a more intense color. It is further described that the films can also be shredded to produce glitter particles. However, the polyterephthalate films used are not biodegradable and cannot be obtained economically from renewable raw material sources.Furthermore, the additional process step of stretching the films means more time and cost for the manufacturing process.

[0009] US 2013 / 0295355 A1 describes a biodegradable, multilayer, transparent, and flexible packaging film consisting of at least a first, PLA-based polymer layer and a second, aliphatic or aliphatic-aromatic copolyester layer, which are arranged alternately, with the first polymer layer forming the outer layer. Optionally, the film can also contain a third polymer layer consisting of an aliphatic or aliphatic-aromatic polyester-based polymer, which is different from the second polymer layer and arranged between the first and second polymer layers. This multilayer film is produced by melt extrusion of each polymer and alternately laminating the extrudates, followed by stretching.It is further described that the individual layer thicknesses of the polymer layers should be between 133 and 5000 nm, since at an individual layer thickness of less than 133 nm (with a refractive index of n=1.465) for the described transparent films, undesirable interference phenomena occur in the visible wavelength range, in particular reddish interference at 780 nm. However, this lower limit of the individual layer thickness severely restricts the available parameter space for achieving further, different color shades. Furthermore, the additional process step of stretching the films means a higher expenditure of time and money for the manufacturing process. However, the effect pigments and multilayer films according to the invention and the advantages achieved thereby were neither described in the prior art nor suggested by it.

[0010] The present invention thus relates to an effect pigment containing, preferably consisting of, two or more transparent layers of a first polymer and two or more transparent layers of a second polymer, wherein the two polymers have a different refractive index and the layers of the first polymer and the layers of the second polymer are arranged in alternating sequence, and wherein the two polymers are selected from biodegradable polymers.

[0011] The invention further provides a process for producing an effect pigment as described above and below, characterized in that the first and second polymers are each coextruded, preferably at elevated temperature, placed on top of one another, optionally cut, stacked and brought into a multilayer film structure through a film die, preferably at elevated temperature, wherein the steps described above can also be repeated several times, and wherein the polymer films are preferably not stretched or drawn after extrusion, the multilayer film thus obtained is punched, ground, cut or comminuted in some other way into particles, and the particles are optionally classified according to size.

[0012] A further subject matter of the invention is a multilayer film containing, preferably consisting of, two or more transparent layers of a first polymer and two or more transparent layers of a second polymer as described above and below, wherein the two polymers have a different refractive index and the layers of the first polymer and the layers of the second polymer are arranged in alternating sequence, the two polymers are selected from biodegradable polymers, and the average individual layer thickness of all polymer layers is <130 nm.The invention further relates to a process for producing a multilayer film as described above and below, characterized in that the first and second polymers are each coextruded, preferably at elevated temperature, placed on top of one another, optionally cut, stacked and brought into a multilayer film structure through a film die, preferably at elevated temperature, wherein the steps described above can also be repeated several times, and wherein the polymer films are preferably not stretched or drawn after extrusion.

[0013] The invention further relates to a formulation comprising one or more effect pigments according to the invention, in particular for use in the above and following products and uses.

[0014] The invention further relates to the use of the effect pigments, multilayer films and formulations according to the invention as described above and below, preferably in products selected from the group consisting of cosmetic products, rinse-off products, packaging materials, decorative films, varnishes, printing inks and plastics.

[0015] The invention further relates to products comprising one or more effect pigments according to the invention, a formulation according to the invention or a multilayer film according to the invention as described above and below, in particular selected from the group consisting of cosmetic products, rinse-off products, packaging materials, decorative films, varnishes, printing inks and plastics.

[0016] According to the EPA network (European Network of Environmental Protection Agency Plastics Interest Group Leaders, Working Paper Nov. 2018*), the term "biodegradable polymers / plastics" as used above and below refers to materials that can potentially be converted into naturally occurring metabolic end products through biological activity (enzymatic cleavage and metabolism with bacteria / fungi). Ideally, this chemical metabolic process leads to mineralization of the plastics into, for example, oxygen, carbon dioxide and its salts, carbon, and methane. The effect pigments and multilayer films according to the invention are characterized, among other things, by an angle-dependent color effect, good adhesion of the individual layers, and good processing properties.In addition, they contain biodegradable materials made from sustainable raw materials, preferably consisting of more than >50% bio-based raw materials, and no inorganic or metallic layers, such as the previously known and commercially available effect foils and glitter pigments.

[0017] The polymers used in the effect pigments and multilayer films according to the invention can be extruded, cut, and stacked simultaneously, do not require subsequent stretching, and exhibit very good adhesion without the need for additional auxiliaries. Suitable polymers are commercially available.

[0018] The pigments and multilayer films according to the invention preferably consist exclusively of organic materials, particularly preferably of biodegradable organic materials, and are preferably free of inorganic materials.

[0019] The two polymers are preferably selected from organic polymers, which may also be cross-linked, and which are biodegradable.

[0020] A particularly preferred material combination consists of PLA (polylactic acid, e.g., made from sustainable corn starch), preferably a copolymer of D- and L-lactic acid monomers, or a PLA blend, as the first polymer, and PBAT (polybutylene adipate / terephthalate), preferably as a random copolymer, as the second polymer. This combination is particularly advantageous because the two copolymers can be coextruded in the same temperature range and their rheological properties, such as viscosity, are well matched.

[0021] Other preferred biodegradable polymers are blends of thermoplastic starch (TPS) with the aforementioned or other biodegradable polymers, blends of PBAT with PLA (e.g. Ecovio series from BASF), Bio-PA6 and Bio-PA11 or polyhydroxyalkanoates such as polyhydroxybutyrate-cohydroxyvalerate (PHB / PHV).

[0022] Depending on the selected polymer combination and the refractive index difference An between the first and second polymer, hereinafter also referred to as polymer A and polymer B, optically visible interference effects with a reflection peak A pea k in the wavelength range from X = 380 to 740 nm nanoscale polymer layer thicknesses dp O iymerA / B according to the following equation (1), where n Powhere A / B denotes the refractive index of polymer A or B, respectively, and the polymer films are not stretched or drawn. Only first-order interference is considered here, since the color effects due to second-order interference are very weak:

[0023] Fig. 1 shows, by way of example, a schematic representation of the formation of the interference effect in effect pigments according to the invention and multilayer films with an alternating, optically active stacking sequence ABABA of individual layers of polymer A (PLA) with a refractive index n of 1.436 and a layer thickness dA, and individual layers of polymer B (PBAT) with a refractive index n of 1.598 and a layer thickness dA, whereby the incident light (arrow "a") is reflected at each interface at which the refractive index changes and the reflected light waves (arrows "b") interfere. The transmitted light is indicated by the arrow "c". The multilayer film is optionally closed with one and the same polymer layer A or B (here: A) on the front and back in order to achieve the necessary film stability. The thickness of these stabilizing cover layers is approximately 8% of the total film thickness and only marginally influences the interference effect.

[0024] Figure 2 shows an example of the formation of the visually visible interference effect, generated by the superposition of reflected radiation with a correspondingly suitable reflection wavelength depending on the individual layer thickness d of the polymers in effect pigments according to the invention and multilayer films with a stacking sequence ABABAB...A (here, A as the stabilizing top layer) and the material combination PLA / PBAT. By specifically varying the individual layer thicknesses, the desired reflection wavelengths and color shades can be achieved for a given refractive index.

[0025] In a preferred embodiment of the invention, the effect pigments and multilayer films have an alternating stacking sequence (ABAB...), where A denotes a single layer of the first polymer (polymer A) and B a single layer of the second polymer (polymer B), and where one of the polymers (polymer A or B) forms the two outer cover layers. e.g.

[0026] ABABABAB....A or BABABA....B. The total number of all optically active individual layers of the first and second polymers in the effect pigments and multilayer films according to the invention of this preferred embodiment is preferably 7 to 2049, in particular 15 to 1025, particularly preferably 31 to 513, very particularly preferably 63 to 257.

[0027] In a further preferred embodiment of the invention, the effect pigments and multilayer films have an alternating stacking sequence (ABAB...), where A denotes a single layer of the first polymer (polymer A) and B a single layer of the second polymer (polymer B), e.g., ABABAB...AB. The total number of all optically active single layers of the first and second polymers in the inventive effect pigments and multilayer films of this preferred embodiment is preferably 8 to 2048, in particular 16 to 1024, particularly preferably 32 to 512, very particularly preferably 64 to 256.

[0028] The average individual layer thickness of all (ie in each of the) polymer layers in the effect pigments and multilayer films according to the invention is preferably <130 nm, particularly preferably 40 to 130 nm, very particularly preferably 60 to 130 nm. The respective color effects can be achieved by combinations of different layer thicknesses dp OiymerA and dp O iymerB. In practice, the ratio of the layer volumes of the individual layers A and B is varied, e.g., to 25 vol%:75 vol%, 50 vol%:50 vol%, or 75 vol%:25 vol%. Deviations in the individual layer thicknesses in the multilayer films lead to multicolored effects, which certainly also find applications and may be desired. In a particularly preferred embodiment of the invention, the effect pigments and multilayer films according to the invention have a reflection wavelength in the visible range of the spectrum, in particular in the range from 450 to 750 nm.

[0029] The total thickness of all polymer layers in the effect pigments and multilayer films according to the invention is preferably 0.5 to 30 .m, particularly preferably 1 to 25 .m, very particularly preferably 4 to 18 .m.

[0030] The refractive index of the first polymer (polymer A), measured at a wavelength X = 633 nm, is preferably 1,200 to 1,700, particularly preferably 1,300 to 1,600, very particularly preferably 1,400 to 1,500. The refractive index of the second polymer (polymer B), measured at a wavelength X = 633 nm, is preferably 1,300 to 1,800, particularly preferably 1,400 to 1,700, very particularly preferably 1,550 to 1,650. The refractive index of the first polymer (polymer A) is preferably smaller than the refractive index of the second polymer (polymer B).

[0031] The refractive index difference Δn between the first and the second polymer at a wavelength X = 633 nm is preferably 0.001 to 0.800, in particular 0.050 to 0.300, particularly preferably 0.100 to 0.200, most preferably at least 0.140.

[0032] The effect pigments and multilayer films according to the invention can also optionally be colored or processed with biodegradable dyes such as liquid dyes (e.g. selected from the DLC series from FARRL) or pre-colored masterbatches (e.g. selected from the Fibaplast masterbatch series from Finke). In a particularly preferred embodiment of the invention, however, the effect pigments and multilayer films according to the invention consist exclusively of the individual layers of the first and second polymers. Preferably, the first and second polymers each have a melting point in the range from 140 to 300°C. Preferably, the difference between the melting points of the first and second polymers is not more than 60°C, particularly preferably not more than 40°C.

[0033] Very particular preference is given to polymers or individual layers which have a refractive index difference An of > 0.14 (at X=633 nm), whereby both polymers can preferably be processed at the same temperature and have an individual layer thickness of 130 nm or less, in particular of 60 to 130 nm.

[0034] In a particularly preferred embodiment of the invention, the individual layer thicknesses for both polymers are almost identical, ie the ratio of the layer volumes is approximately 50:50.

[0035] The effect pigments according to the invention preferably have a maximum diameter of 1 to 200 .m, particularly preferably 5 to 160 .m, very particularly preferably 10 to 120 .m.

[0036] The effect pigments according to the invention are preferably platelet-shaped. The effect pigments according to the invention preferably have an aspect ratio (shape factor or diameter / thickness ratio) of 1 to 200, particularly preferably 5 to 100, very particularly preferably 6 to 20.

[0037] The effect pigments according to the invention preferably have a regular n-corner shape with n = 3 to 16, preferably 4 to 8. These or other preferred shapes can be produced in a manner known to the person skilled in the art by using suitable tools or devices for comminuting the multilayer films, such as grinding tools.

[0038] The particle sizes are determined using commercially available equipment known to those skilled in the art (e.g., from Malvern, Horiba) by means of laser diffraction on powder or pigment suspensions. A further preferred embodiment of the invention relates to a mixture consisting of two or more effect pigments according to the invention with different hues.

[0039] A further preferred embodiment of the invention relates to a mixture consisting of two or more effect pigments according to the invention with different particle sizes and / or different color shades.

[0040] The effect pigments according to the invention preferably have a metallic-looking color effect, particularly preferably gold, copper or silver.

[0041] In a preferred embodiment of the invention, the process according to the invention for producing effect pigments and multilayer films comprises the following steps:

[0042] The first and second polymers are each extruded, preferably at elevated temperature, stacked, optionally cut, stacked, and extruded through a film die, preferably at elevated temperature, into a multilayer film structure. The steps described above can also be repeated several times.

[0043] Preferably, the polymer films are not stretched or drawn after extrusion.

[0044] The extrusion preferably takes place at an elevated temperature, in particular at a temperature above 180°C, most preferably at a temperature above 200°C.

[0045] The multilayer film buildup through the film die preferably takes place at elevated temperature, in particular at a temperature > 160°C, most preferably at a temperature > 180°C. To produce the effect pigments according to the invention, the multilayer film thus obtained is subsequently punched, ground, cut, or otherwise comminuted into particles, and the particles are optionally classified by size.

[0046] Other suitable process conditions, aids and devices not described in detail here, such as extruders, film nozzles or grinding tools, are known to the person skilled in the art and are described in the literature.

[0047] The invention further relates to the use of the effect pigments, multilayer films and formulations according to the invention as described above and below, preferably in products selected from the group consisting of cosmetic products, rinse-off products, packaging materials, decorative films, varnishes, printing inks and plastics.

[0048] The invention further relates to formulations comprising one or more effect pigments according to the invention, in particular for use in the above and following products and applications.

[0049] The invention further relates to products comprising one or more effect pigments or multilayer films according to the invention as described above and below.

[0050] The effect pigments according to the invention can be used in a variety of ways, e.g., in products selected from cosmetic products, rinse-off products, packaging materials, decorative films, paints and varnishes, in particular selected from cosmetic or rinse-off formulations, automotive coatings, powder coatings, printing inks, security printing inks, plastics, ceramic materials, glasses, paper, paper coatings, toners for electrophotographic printing processes, seeds, greenhouse films, tent tarpaulins, for producing pigment coatings with water, organic and / or aqueous solvents, for producing pigment preparations or dry preparations, for mass coloring of foodstuffs, for coloring coatings of food products or pharmaceutical products, and in valuable documents. The production of such products is carried out in a manner known to the person skilled in the art.

[0051] The effect pigments according to the invention can be used in cosmetic applications, preferably, for example, in lipsticks, lip gloss, rouge, eyeliner, eye shadow, (volumizing) mascara, nail polishes, day creams, night creams, body lotions, cleansing milk, body powder, sticks, hair gels, hair masks, hair dyes, hair conditioners, hair shampoos, shower gels, shower baths, shower oils, bath additives, sunscreen, makeup, skin care creams, lotions, soaps, bath salts, toothpaste, face masks, pressed powders, loose powders and gels, etc. The production of such products takes place in a manner known to the person skilled in the art.

[0052] The multilayer films according to the invention are particularly suitable for use in cosmetic products as well as in and / or as packaging materials and decorative films (also referred to as effect films).

[0053] For various applications, the effect pigments according to the invention can also be used in admixture with other absorption pigments and / or effect pigments, such as pearlescent pigments, effect pigments, goniochromatic pigments, BiOCl platelets, multilayer pigments, metallic pigments, organic dyes, organic color pigments and other pigments, such as transparent and opaque white, colored and black pigments as well as with platelet-shaped iron oxides, holographic pigments, LCPs (liquid crystal polymers) and conventional transparent, colored and black luster pigments based on metal oxide-coated mica and SiO2 platelets, etc. The effect pigments according to the invention can be mixed in any ratio with commercially available (effect) pigments.

[0054] The effect pigments and multilayer films according to the invention can also optionally be colored with natural dyes.Furthermore, the formulations and products according to the invention can also contain, in addition to the effect pigments according to the invention, further components or additives, in particular selected from the group consisting of absorbents, astringents, antimicrobial substances, antioxidants, antiperspirants, antifoams, antidandruff active ingredients, antistatic agents, binders, biological additives, bleaching agents, chelating agents, deodorants, emollients, emulsifiers, emulsion stabilizers, dyes, humectants, film formers, fillers, fragrances, flavorings, insect repellents, preservatives, corrosion inhibitors, cosmetic oils, solvents, oxidizing agents, plant components, buffer substances, reducing agents, surfactants, propellants, opacifiers, UV filters and UV absorbers, denaturants, viscosity regulators, perfume and vitamins.

[0055] Even without further elaboration, it is assumed that a person skilled in the art can utilize the above description to the fullest extent possible. The preferred embodiments and examples are therefore to be construed merely as descriptive and not as limiting disclosures in any way. All starting components are either commercially available or can be synthesized using known methods.

[0056] Example 1

[0057] To produce blue effect pigments, PLA is used as polymer A and PBAT as polymer B in a 50:50 volume ratio. PLA stands for polylactic acid; the commercial product used is lngeo® 4043 from NatureWorks with a refractive index of n=1.454 (at 633 nm). PBAT stands for polybutylene adipate terephthalate, a statistical copolymer of the monomers 1,4-butanediol, adipic acid, and terephthalic acid; the commercial product used is Ecoflex® F-Blend C1200 from BASF with a refractive index of n=1.598 (at 633 nm).

[0058] The two polymers A and B are extruded in a coextrusion process at 215°C, alternately stacked, i.e. cut and stacked at 215°C, and formed into the final film shape through a film die at 210°C.

[0059] This simultaneous processing at the same temperature is made possible by the similar dynamic viscosity of both polymers in the range of 0.2–0.4 MPa*s. Five cutting / stacking processes produce a multilayer film consisting of a total of 64 individual layers, each with a thickness of 60 nm.

[0060] The multilayer film is then cut / punched into particles ranging in size from 5 to 200 pm. Pigment particles are obtained that exhibit a blue, metallic hue.

[0061] Example 2

[0062] To produce greenish-metallic effect pigments, PLA is used as polymer A and PBAT as polymer B as described in Example 1.

[0063] The two polymers A and B are extruded in a co-extrusion process at 215°C, alternately stacked (i.e., cut and stacked at 215°C), and then formed into the final film shape through a film die at 210°C. This simultaneous processing at the same temperature is made possible by the similar dynamic viscosity of both polymers in the range of 0.2-0.4 MPa*s. Six cutting / stacking processes produce a multilayer film consisting of a total of 128 individual layers with a PLA single-layer thickness of 125 nm and a PBAT single-layer thickness of 115 nm.

[0064] The multilayer film is then cut / punched into particles ranging in size from 5 to 200 pm. This results in pigment particles with a greenish, metallic hue.

[0065] Example 3

[0066] To produce reddish-gold and copper-metallic effect pigments, PLA is used as polymer A and PBAT as polymer B, as described in Example 1. The two polymers A and B are extruded in a co-extrusion process at 215°C, alternately stacked, i.e., cut and stacked at 215°C, and then formed into the final film shape through a film die at 210°C. This simultaneous processing at the same temperature is made possible by the similar dynamic viscosity of both polymers in the range of 0.2-0.4 MPa*s. Six cutting / stacking processes produce a multilayer film consisting of a total of 128 individual layers with a PLA single layer thickness of 125 nm and a PBAT single layer thickness of 160 nm.

[0067] The multilayer film is then cut / punched into particles ranging in size from 5 to 200 pm. This produces pigment particles with a reddish-gold or copper-metallic hue.

[0068] Example 4

[0069] By mixing green, red and blue metallic pigment particles produced according to examples 1 to 3, a silver-lustrous mixture of effect pigments is obtained.

[0070] The above examples demonstrate that effect pigments and multilayer films according to the invention can be produced from commercially available, biodegradable polymers in a simple and cost-effective process, directly and without further additives or process steps such as stretching, etc., and in a wide variety of colors.

[0071] In contrast, commercially available silver glitter pigments such as 1S Silver or 2S Bright Silver from Moplatec / RJA Plastics GmbH are not made of biodegradable materials, but are cut from a polymer film consisting of a PET core that is vacuum-coated with aluminum on one side and then provided with an epoxy protective film on both sides.

Claims

Patent claims Effect pigment containing, preferably consisting of, two or more transparent layers of a first polymer and two or more transparent layers of a second polymer, wherein the two polymers have a different refractive index and the layers of the first polymer and the layers of the second polymer are arranged in alternating sequence, and wherein the two polymers are selected from biodegradable polymers. Effect pigment according to claim 1, characterized in that the average individual layer thickness of all polymer layers is < 130 nm. Effect pigment according to claim 1 or 2, characterized in that the first polymer is PLA (polylactic acid) or a PLA blend and the second polymer is PBAT (polybutylene adipate terephthalate), in particular as a random copolymer.Effect pigment according to one or more of claims 1 to 3, characterized in that the average individual layer thickness of all polymer layers is 40 to 130 nm, particularly preferably 60 to 130 nm. Effect pigment according to one or more of claims 1 to 4, characterized in that the total number of all individual layers of the first and second polymers is 7 to 2049, in particular 15 to 1025, particularly preferably 31 to 513, very particularly preferably 63 to 257. Effect pigment according to one or more of claims 1 to 5, characterized in that the refractive index of the first polymer at a wavelength λ = 633 nm is 1,200 to 1,700, particularly preferably 1,300 to. 1,600, most preferably 1,400 to 1,500 and the refractive index of the second polymer (polymer B) at a wavelength X = 633 nm is preferably 1,300 to 1,800, particularly preferably 1,400 to 1,700, most particularly preferably 1,550 to 1,650.

7. Effect pigment according to one or more of claims 1 to 6, characterized in that the refractive index difference Δn between the first and the second polymer at a wavelength X = 633 nm is 0.001 to 0.800, in particular 0.050 to 0.300, particularly preferably 0.100 to 0.200, very particularly preferably at least 0.

140.

8. Effect pigment according to one or more of claims 1 to 7, characterized in that the total thickness of all polymer layers is 0.5 to 30 .m, particularly preferably 1 to 25 .m, very particularly preferably 4 to 18 .m.

9. Effect pigment according to one or more of claims 1 to 8, characterized in that it has a shape factor (diameter / thickness ratio) of 1 to 200, preferably of 5 to 100, particularly preferably of 6 to 20.

10. A process for producing an effect pigment according to one or more of claims 1 to 9, characterized in that the first and the second polymer are each extruded, placed one on top of the other, optionally cut, stacked and brought into a multilayer film structure through a film die, preferably at elevated temperature, wherein the steps described above can also be repeated several times, and wherein the polymer films are preferably not stretched or drawn after extrusion, the multilayer film thus obtained is punched, ground, cut or comminuted in some other way into particles, and the particles are optionally classified according to size.

11. Formulation containing one or more effect pigments according to one or more of claims 1 to 9.

12. Use of the effect pigment according to one or more of claims 1 to 9 or of the formulation according to claim 11 in products selected from the group consisting of cosmetic products, rinse-off products, packaging materials, decorative films, varnishes, printing inks and plastics.

13. A product selected from the group consisting of cosmetic products, rinse-off products, packaging materials, decorative films, varnishes, printing inks and plastics, containing one or more effect pigments according to one or more of claims 1 to 9 or a formulation according to claim 11.

14. Formulation according to claim 11 or product according to claim 13, containing one or more additives selected from binders, effect pigments and absorption pigments.

15. Multilayer film containing, preferably consisting of, two or more transparent layers of a first polymer and two or more transparent layers of a second polymer, wherein the layers of the first polymer and the layers of the second polymer are arranged in alternating sequence, the two polymers are as defined in one or more of claims 1 to 8, and the average individual layer thickness of all polymer layers is <130 nm.

16. A process for producing a multilayer film according to claim 15, characterized in that the first and the second polymer are each extruded, preferably at elevated temperature, placed on top of one another, optionally cut, stacked and brought into a multilayer film structure through a film die, preferably at elevated temperature, wherein the steps described above can also be repeated several times, and wherein the polymer films are preferably not stretched or drawn after extrusion.

17. Use of a multilayer film according to claim 15 in and / or as packaging materials or decorative films.

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