HK1113476B - Laser-markable molding masses and products obtained therefrom and method for laser marking - Google Patents

Description

Laser-markable molding compositions, products obtained therefrom and laser-marking process

Technical Field

The invention relates to novel molding compositions based on partially crystalline engineering thermoplastics which lead to laser-markable moldings having improved marking quality. The invention further relates to molded articles prepared from these laser-markable molding compositions, to a laser-marking process, and to the use of selected additives for laser marking.

Background

Partially crystalline thermoplastics have been used as materials for a long time. In addition to the mechanical, thermal, electrical and chemical properties of these materials, functionality such as the ability to mark with a laser is increasingly appreciated. For example, applications in the field of household products, in the field of keyboards and in the field of electronic devices should be mentioned. This application requires a high contrast between the laser-inscribed marking and the polymer matrix as background. Furthermore, factors which are of aesthetic interest are the targeted adjustment of the color of the marking as well as of the substrate, and the surface properties of the marking. Durability at high perceived quality (Wertanmutung) should be ensured, especially when the laser marked surface is usually made visible or regularly exposed to mechanical or chemical stress in use. In many cases, this is an obstacle to the use of partially crystalline engineering thermoplastics.

Laser-markable molding compositions are known per se. One possible marking scheme of these molding compositions using lasers is to irradiate selected locations on the plastic with a laser and to use the energy introduced to cause a mechanical change or a local discoloration of the plastic. Another possible way of marking these molding compositions with laser light is to use color-changeable fillers which change their color by laser radiation at selected locations.

EP-A-190,997 discloses ｃA process for laser marking of pigmented systems, in which radiation-sensitive additives which cause discoloration are incorporated into the high molecular weight material. The disclosed additives include, inter alia, TiO₂And Sb₂O₃。

The use of various additives in laser-markable plastic molding compositions is described in various patent documents. For example, EP-A-330,869 discloses TiO₂The use of white pigments. EP-A-400,305 and EP-A-542,115 describe the use of copper (IV) hydroxide phosphate and molybdenum (IV) oxide, respectively.

US-A-5,063,137 discloses, inter aliA, the use of anhydrous metal phosphate and phosphate based glasses.

EP-A-797,511 describes the use of flake-form pigments having ｃA layer consisting of doped tin oxide.

US-A-5,489,639 describes the use of selected copper salts (phosphates, sulphates, thiocyanates).

EP-A-764,683 discloses the use of copper pyrophosphate hydrate and/or manganese sulfate hydrate.

EP-A-808,866 discloses the use of boric anhydride.

WO-A-98/58805 discloses A series of copper phosphates.

WO-A-99/55773 describes, inter aliA, the use of zinc hydroxystannate and tin (II) oxalate.

DE-A-19905358 discloses the use of alkali metal copper diphosphates.

WO-A-01/00719 describes Sb particles having A size of more than 0.5 μm₂O₃The use of (1).

EP-A-1,190,988 discloses the use of specific bismuth mixed oxides.

WO-A-01/78994 proposes the use of copper fumarate, copper maleate and mixtures thereof.

DE-A-10053639 proposes the use of selected salts, in particular various cobalt phosphates and iron phosphates.

DE-A-10034472 describes the use of particles surface-modified with specific silicon compounds.

EP-A-753,536 describes the use of at least two metal oxides.

EP-A-105,451 describes polyphenylene sulfide molding compositions which have been modified for laser marking with selected additives, for example with ｃA combination of lead chromate and lead molybdate, with nickel antimony titanate, or with cobalt-zinc-silicon.

The laser-markable plastic molding compositions available to date should be improved in some respects.

Pigments used for laser inscription often produce only an insufficient color difference between the marked region and the unirradiated plastic substrate, so that a poor color contrast and poor inscription readability are achieved. In other cases, the initially acceptable color contrast changes over time, with the result that the inscription more or less disappears. As the amount of pigment added increases, there is also a risk of undesirable changes in the properties of the plastic.

If light-scattering particles are used as laser-sensitive additives, which act as white pigments, this solution is limited by the following: although the photosensitivity increases with increasing additive content, both the contrast of the mark and the penetration depth of the mark may decrease.

If metal compounds (e.g., oxides or salts) are used, the inherent color of each typically contributes to the discoloration of the substrate and is generally aesthetically detrimental.

Disclosure of Invention

Starting from the prior art described above, the object on which the present invention is based was to provide molding compositions based on partially crystalline engineering thermoplastics which can be marked with conventional lasers and in which the color of the substrate, the color of the marking and the surface morphology of the marking can be optimized with good marking contrast without this leading to a disproportionate impairment of the remaining performance aspects of the engineering thermoplastics.

Surprisingly, molding compositions have now been found which adequately avoid the disadvantages described.

The present invention provides laser-markable molding compositions comprising

A) At least one partially crystalline thermoplastic and

B) at least one particulate photosensitive salt-type compound that changes its color or causes a color change in the plastic composition when exposed to laser light, and which comprises a plurality of cations, wherein one cation is selected from the group consisting of: ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ag, Sn, Sb, La, Pr, Ta, W, Ce, another cation selected from: elements of the main groups 3 to 6 of the II and III of the periodic Table of the elements, elements of the main groups 5 to 6 of the IV of the periodic Table of the elements and elements of the subgroups 4 to 5 of the III to VIII of the periodic Table of the elements and lanthanides, and/or

C) At least one particulate inorganic oxide having an average particle diameter of less than 250nm, preferably less than 200nm, and

D) optionally, other conventional additives.

According to the invention, a particulate photosensitive salt compound or mixture is used as component B), which contains a plurality of cations. In particular cases, the cation is selected such that, when the salt-type compound B) is incorporated into component A), it does not cause the color of the molding composition to change or causes it to change in the desired manner. In addition, the mass ratio of the cations to one another is selected such that, after irradiation of the molding composition, the color of the matrix is not changed, although the brightness of the molding composition changes at the irradiated sites.

Average particle size (d) of component B₅₀) Preferably less than 10 μm. Suitable primary particles may range in size from a few nanometers up to a few micrometers.

Component B must comprise at least two different cations selected from the above mentioned cation groups. Optionally, other cations may be present, for example cations consisting of elements of group I, periods 2 to 5 of the periodic Table of the elements.

According to the invention, particulate additives are used as component C), which on the one hand increase the sensitivity of the molding compositions to laser light, but on the other hand scatter little light. Inorganic oxides, which, although having a different refractive index than the matrix, contain an average diameter (d), generally meet this criterion₅₀) Primary particles smaller than the wavelength of light.

The formulation components of the molding compositions according to the invention are therefore a matrix (A) comprising the partly crystalline engineering thermoplastic, and also additives (B) in the form of particulate photosensitive compounds or mixtures having the above-defined cation combination, and/or additives (C) in the form of nanoparticulate inorganic oxides, and, optionally, further conventional additives (D).

Surprisingly, both types of particulate additives complement each other in a non-trivial manner. Both component B and component C increase the sensitivity to laser light upon interaction with the matrix a.

Component B optionally together with other pigmenting additives or pigments influences the inherent color of the matrix as well as the color of the marking.

If the choice of component C is suitable, its influence on the color development of the matrix and of the marking remains small.

For the purposes of the present application, laser-inscribable molding compositions are characterized by a discoloration at the irradiated sites in comparison with the unirradiated substrate when irradiated with intense light, preferably originating from a conventional laser source. This color difference can be detected as locally different luminance, as locally different color values, for example in the CIELab system, or as locally different color values in the RGB system. These effects may occur under different light sources.

The components B) and/or C) are generally selected such that they have as strong an absorption as possible in the wavelength range of the available laser light.

The wavelength range of the laser used is in principle not subject to any restrictions. Suitable lasers have a wavelength of typically 157nm to 10.6 μm, preferably 532nm to 10.6. mu.m.

By way of example, CO may be mentioned here₂Lasers (10.6 μm) and Nd: YAG lasers (1064nm) or pulsed UV lasers.

The wavelengths of a typical excimer laser are as follows: f₂Excimer laser (157nm), ArF excimer laser (193nm), KrCl excimer laser (222nm), KrF excimer laser (248nm), XeCl excimer laser (308nm), XeF excimer laser (351nm), frequency-doubled Nd, with wavelength of 532nm (double frequency), 355nm (triple frequency) or 265nm (quadruple frequency).

Particularly preferably, a Nd: YAG laser (1064 or 532nm) and CO are used₂A laser.

The energy density of the laser used in the present invention is usually 0.3mJ/cm²-50J/cm²Preferably 0.3mJ/cm²-10J/cm². If a pulsed laser is used, the pulse frequency is typically 1-30 kHz.

The molding compositions according to the invention generally comprise from 50 to 99.95% by weight, preferably from 80 to 99.5% by weight, particularly preferably from 95 to 99% by weight, of a matrix component (A) which comprises one or more partially crystalline engineering thermoplastics. Since the matrix is by definition partially crystalline and therefore opaque in the micro-regions of different refractive index, it is primarily the near-surface component that contributes to the laser marking.

Polymers that can be used in the matrix are not only those with linear chain-like molecules, but also branched or slightly crosslinked polymers. The degree of polymerization of the partially crystalline thermoplastics useful in the present invention is not subject to any particular limitation and is of the same order of magnitude as those of similar molding compositions which are not writable by light.

The matrix component (A) used in the present invention must be partially crystalline, i.e.the thermoplastics which can be used exhibit a melting range in the DSC curve.

The matrix component (a) used in the present invention is not subject to any particular limitation so long as it is a thermoplastic and partially crystalline polymer.

Examples of partially crystalline thermoplastics (a) which can preferably be used are polyacetals (a1), polyesters (a2), polyamides (A3), polyarylene ethers and polyarylene sulfides (a4), polyether sulfones and polysulfones (a5), polyaryl ether ketones (a6), polyolefins (a7), liquid-crystalline polymers (A8), and optionally further thermoplastic polymers (AX) as blend partners.

For the purposes of the present description, the polyacetal (A1) has as its main repeating unit an oxymethylene group (CH)₂O-). These include polyoxymethylene homopolymers, polyoxymethylene copolymers, polyoxymethylene terpolymers and polyoxymethylene block copolymers.

For the purposes of the present description, polyesters (A2) are thermoplastic polymers having recurring ester groups in the main chain. Examples are the polycondensation products of: naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, cyclohexanedicarboxylic acids, mixtures of these carboxylic acids and derivatives capable of forming esters, with diols such as ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 4-butenediol and 1, 6-hexanediol, 1, 4-cyclohexanediol, 1, 4-di (hydroxymethyl) cyclohexane, bisphenol A, neopentyl glycol, oligo-or polyethylene glycols, oligo-or polypropylene glycols, oligo-or poly (tetramethylene) glycols, mixtures of these glycols and their derivatives capable of forming esters, and with further possible comonomers of the AA, BB and AB type.

Particularly preferred matrix components (A) are polyethylene terephthalate, polybutylene terephthalate and polyether-ester block copolymers.

For the purposes of the present description, polyamides (A3) are thermoplastic polymers having recurring amide groups in the main chain. They include not only homopolymers of the aminocarboxylic acid type but also those of the diamine-dicarboxylic acid type, in addition to copolymers with other possible comonomers of the AA, BB and AB type. Polyamides which can be used are known and are described, for example, in Encyclopedia of Polymer science and Engineering, Vol.11, p.315 & 489, John Wiley & Sons, Inc. 1988.

Examples of polyamides (A3) are polyhexamethylene adipamide, polyhexamethylene azelamide, polyhexamethylene sebacamide, polyhexamethylene dodecanoamide, poly-11-aminoundecanoamide and bis (p-aminocyclohexyl) methanedodecanediamide, or products obtained via ring opening of lactams, for example polycaprolactam or polylaurolactam. Other suitable polyamides are those based on terephthalic acid or isophthalic acid as acid component and/or trimethylhexamethylenediamine or bis (p-aminocyclohexyl) propane as diamine component, as well as polyamide matrix (grund) resins prepared via copolymerization of two or more of the above polymers or their components. Examples which may be mentioned here are copolycondensates composed of terephthalic acid, isophthalic acid, hexamethylenediamine and caprolactam.

For purposes of this specification, polyarylene sulfide (A4) is a thermoplastic polymer having repeating sulfur groups in a substantially aromatic backbone. They include not only homopolymers but also copolymers.

For the purposes of the present description, the liquid-crystalline polymers (A8) are in particular liquid-crystalline copolyesters and copolyesteramides based on p-hydroxybenzoic acid and/or 6-hydroxy-2-naphthoic acid. Very particularly advantageously as liquid-crystalline plastics are generally completely aromatic polyesters which form anisotropic melts and have average molecular weights (Mw ═ weight) of 2000-200000g/mol, preferably 3500-50000g/mol and in particular 4000-30000 g/mol. Particularly suitable liquid-crystalline polymers are described, for example, in Saechtling, Kunststoff-Taschenbuch (Plastic pocket handbook), Hanser-Verlag, 27 th edition, page 517-521.

For the purposes of the present description, the thermoplastic polymer (AX) used as a blend partner may be any desired other partially crystalline, liquid crystalline or amorphous polymer.

For the purposes of the present description, the photosensitive compounds (B) are organic or inorganic salt-type compounds having a combination of different cations as defined above, or mixtures of salt-type compounds having a combination of different cations as defined above, which, when exposed to a laser source, change their color at the irradiated site or cause a discoloration of the plastic.

The compound (B) may be a classical salt with a defined stoichiometry, consisting of one or more anions and a plurality of cations derived from different elements, but at least two cations, but it may also be a compound with a non-stoichiometric composition, having at least two cations derived from different elements.

The occurrence of ion exchanger functionality for a given anion system is a possible evidence of such complex structure formation, incorporating a variety of different cations.

In one possible embodiment of the invention, a mixture of compounds each having one cation is used, which mixture, when heated, can be converted into at least one compound having two cations.

The above definitions of the inventive concept include in particular the following embodiments, which can be used as alternatives or in combination with each other. In one embodiment, the additives used in the molding compositions of the invention themselves have at least two different cations, which are formed, for example, via the reaction of at least two simple salts, each having one cation, and are in the form of a mixed salt (B) in the polymer matrix (A) to form the molding compositions of the invention. Another embodiment selects the same cations as the first embodiment, but consists of a mixture of simple salts that have not reacted with each other. This embodiment is possible if the salts present in the mixture react under elevated temperature and otherwise customary conditions (e.g.residual moisture) to give a mixed salt, i.e.a novel reaction product (B), to give the molding compositions according to the invention.

Various variations of the latter embodiment aspect are possible. The simple salt-type compounds present in the mixture can be reacted with one another before addition to the plastic matrix (A) to form salt-type compounds having cations in accordance with the selection rules of the invention, which reaction products can then be used as additives (B) for the molding compositions of the invention. In another embodiment, a mixture of simple salts is mixed into the plastic matrix (a) to be rendered laser-inscribable. When the parent composition is then heated, the simple salt-type compounds react with each other and produce the same or similar multiple salts, which are the same as or at least similar to those in the first part of this example.

Elements whose cations can be used for the photo-induced discoloration are Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ag, Sn, Sb, La, Pr, Ta, W and Ce.

Elements whose cations supplement those mentioned are those selected from the group consisting of the main groups II and III, periods 3 to 6, the main groups IV, periods 5 to 6 and the subgroups III to VIII, periods 4 to 5 and the lanthanides.

Optionally, cations of elements of the first main group 2 to 5 of the periodic Table of the elements may also be present as third component.

The anion of component (B) is in principle not subject to any restriction, provided that a compound with cations of at least two different elements can be formed therefrom.

The anions preferably used in component (B) are those containing at least two different elements.

Particularly preferred components (B) have inorganic Oxo (Oxo) anions, or anions of organic carboxylic acids, or anions of carbonic acid as anions, as long as mixed compounds with a plurality of cations can be achieved with them. Particularly preferred anions of component (B) are phosphorus-containing oxy anions.

Those combinations in which the unirradiated compound (B) absorbs in the wavelength range of the light used are preferred.

Furthermore, preference is given to those combinations in which the intrinsic color of the non-irradiated compound (B) can be adjusted via a change in the molar ratio of the cations.

In one embodiment of the present invention, the unirradiated molding composition has any desired intrinsic color and the irradiated molding composition has as pronounced a color difference as possible therewith. If color difference is mentioned here, it may mean the transition from one hue to another, for example from yellow to red. However, for the purposes of the present invention, this term is also intended to mean a change in brightness, for example from white to grey, from grey to black, or from light brown to dark brown. The term "color difference" is also intended to mean a change in opacity, for example a change from transparent to white or black or brown.

The chromatic aberration can be perceived by the human eye. The invention also relates to chromatic aberrations detected by optical measuring devices or those detected by detectors at wavelengths outside the sensitive range of the human eye. An example which may be mentioned here is the application of a reader which uses a diode laser in the NIR range.

For the visible range, the CIELab system can be used to describe the color difference. Here, the high color contrast means dE^*A high value appears, wherein

Wherein subscript 1 represents the unirradiated molding composition and subscript 2 represents the irradiated molding composition.

The CIELab system is a color space defined by the Commission International' Eclairage) in 1976, where L^*Brightness, a^*Red-green information, b^*Yellow-blue information.

In a preferred embodiment of the present invention, the unirradiated molding compositions have a brightness which is as high as possible (i.e.a brightness value L which is as high as possible in the CIELab color space)^*) And as little intrinsic color as possible (i.e. as little deviation from the black-white axis as possible: a is as small as possible in a quantitative sense^*B is as small as possible in a quantitative sense^*). In this case, it is desirable for the irradiated molding compositions to have a brightness which is as low as possible (a brightness value L which is as low as possible)^*) But still has as little intrinsic color as possible (as little a as quantitatively possible)^*To determineB is as small as possible in terms of quantity^*)。

In a further preferred embodiment of the present invention, the unirradiated molding compositions have a brightness as high as possible (as high as possible a brightness value L in the CIELab color space)^*) And as little intrinsic color as possible (i.e. as little deviation from the black-white axis as possible: a is as small as possible in a quantitative sense^*B is as small as possible in a quantitative sense^*). In this case, it is desirable that the irradiated molding compositions should have as pronounced intrinsic color as possible (as high a as possible in a quantitative sense)^*And/or b^*)。

In a preferred embodiment of the composition of the invention, the anion of component (B) has the general formula A_aO_o(OH)_y ^z-Wherein a is tri-or pentavalent phosphorus, tetravalent molybdenum or hexavalent tungsten, a, o and z are, independently of one another, integers having a value of 1 to 20, and y is an integer having a value of 0 to 10.

In another preferred embodiment of the composition according to the invention, component (B) has as cation at least one combination of two different elements selected from the group consisting of copper, tin, antimony and iron.

In a particularly preferred embodiment of the composition according to the invention, component (B) has the anion of the phosphorus (V) acid and/or of the phosphorus (III) acid, their condensation products, and, optionally, further hydroxide ions, and has, as cations, Cu and Fe, or Cu and Sn, or Cu and Sb, or Sn and Fe.

In addition to the chemical composition, the physical parameters of component (B), such as the particle size, also have a decisive influence on the quality of the laser-inscribability. They influence, by their scattering behavior, not only the color value and the brightness value of the unirradiated substrate, but also the optical homogeneity in the irradiated and unirradiated regions. The average particle size is also an important measure of the dispersibility in the polymer matrix and therefore also influences the light sensitivity of the molding compositions.

Component (B) having an average particle diameter of less than 10 μm has proven suitable. The average particle diameter of component (B) is preferably less than 5 μm.

Quantitative data on particle size in the present application always relate to the mean particle size (d)₅₀) And the particle size of the primary particles. For the purposes of the present invention, particle size is determined by conventional methods, for example by light scattering (optionally using polarized light), microscopy or electron microscopy, counting narrow gap flow measurements, sedimentation or other commercially available methods.

The proportion of component B) used is advantageously from 0.01 to 2.0% by weight. A content of 0.02 to 1.0% by weight is particularly preferred.

For the purposes of the present description, the photosensitizing inorganic oxide (C) is an oxide which promotes the formation of a coloring compound when exposed to light radiation. This may be on the one hand a change in the intrinsic color of these oxides or may be a catalytic contribution, i.e. the formation of compounds with suitable absorption properties in the vicinity of their space.

For the purposes of the present description, the term "oxide" also refers to a compound in which a portion of the oxygen atoms are present in the form of hydroxyl groups. In this case, it may also refer to compounds having a stoichiometric and non-stoichiometric composition.

Suitable inorganic oxides for component (C) can be based on the elements of main groups III and IV, periods 3 to 6, main group V, and transition groups III to VIII, periods 4 to 5, and the lanthanides.

The oxide (C) preferably used is Al₂O₃、SiO₂Silicate and aluminosilicate minerals, silicate glass, TiO₂、ZnO、ZrO₂、SnO₂、Sb₂O₃、Sb₂O₅、Bi₂O₃And, optionally, mixed oxides with other doping elements. TiO in anatase and rutile form₂And is especially preferred.

In addition to the chemical composition, the physical parameters of component (C), such as the particle size, also have a decisive influence on the quality of the laser-inscribability. If the oxide additive acts as a permanent white pigment due to its scattering behavior, the brightness values of the non-irradiated and irradiated sites are increased, thus limiting the contrast of the marking. Furthermore, the average particle size is an important measure of the maximum particle-matrix interface which can be achieved with good dispersion and therefore also influences the light sensitivity of the molding compositions.

Suitable components (C) have been found to be those having an average particle diameter of less than 250 nm. For the purposes of the present invention, the particle size is determined, for example, by electron beam methods or X-ray methods. The average particle diameter of component (C) is preferably less than or equal to 200nm, in particular less than or equal to 100nm, particularly preferably from 10 to 100 nm. The particle sizes given are based on the primary particles in the additive used. Depending on the quality of the dispersion, agglomerates of these primary particles may form in the matrix, which agglomerates naturally may have a larger diameter.

The proportion of component C) used is advantageously from 0.01 to 2.0% by weight. A content of 0.02 to 1.0% by weight is particularly preferred.

Other conventional additives (D) are optional constituents of the thermoplastic molding compositions of the invention.

By way of example, they include stabilizers (D1) for improving light resistance, UV radiation resistance and weathering resistance, stabilizers (D2) for improving heat resistance and resistance to thermooxidative oxidation, stabilizers (D3) for improving hydrolysis resistance, stabilizers (D4) for improving resistance to acidolysis, lubricants (D5), mold release aids (D6), coloring additives (D7), crystallization modifiers and nucleating agents (D8), flame retardants (D9), impact modifiers (D10), fillers (D11), plasticizers (D12) and, optionally, other conventional additives (D13).

The stabilizers (D1) which may be present in the molding compositions according to the invention for weathering and light and UV radiation are one or more substances selected from the group consisting of: (D1A) benzotriazole derivatives, (D1B) benzophenone derivatives, (D1C) oxanilide derivatives, (D1D) aromatic benzoates such as salicylates, (D1E) cyanoacrylates, (D1F) resorcinol derivatives and (D1G) sterically hindered amines.

In a preferred embodiment, the molding compositions of the invention comprise not only at least one of the stabilizers from the class D1A to the class D1F, but also sterically hindered amines of the class D1G.

In a particularly preferred embodiment, the molding compositions of the invention comprise the benzotriazole derivative D1A in combination with a hindered amine D1G.

Examples of (D1A) benzotriazole derivatives are 2- [2 '-hydroxy-3', 5 '-bis (1, 1-dimethylbenzyl) phenyl ] benzotriazole, 2- [ 2' -hydroxy-3 '-tert-butyl-5' -methylphenyl) -5-chlorobenzotriazole, 2- (2 '-hydroxy-5' -methylphenyl) benzotriazole.

Examples of benzophenone derivatives (D1B) are 2-hydroxy-4-n-octyloxy-benzophenone and 2-hydroxy-4-n-dodecyloxy-benzophenone.

Examples of sterically hindered amines (D1G) are 2, 2, 6, 6-tetramethyl-4-piperidyl compounds, such as bis (2, 2, 6, 6-tetramethyl-4-piperidyl) sebacate, or polymers of dimethyl succinate and 1- (2-hydroxyethyl) -4-hydroxy-2, 2, 6, 6-tetramethyl-4-piperidine.

The mentioned weathering stabilizers (D1) are advantageously used in proportions of 0.01 to 2.0% by weight. A total content of 0.02 to 1.0% by weight of D1A to D1G is particularly preferred.

The moulding compositions according to the invention may comprise antioxidants as stabilizers (D2) for improving the heat resistance and the resistance to thermooxidation, for example one or more substances selected from the group consisting of: (D2A) sterically hindered phenols, (D2B) phenol ethers, (D2C) phenol esters of organic acids or phosphorus-containing acids, for example pentaerythritol tetrakis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], triethylene glycol bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate ], 3' -bis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionohydrazide ], hexanediol bis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], 3, 5-di-tert-butyl-4-hydroxytoluene, (D2D) hydroquinone and (D2E) secondary aromatic amines.

Pentaerythritol tetrakis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], hydroquinone (D2D) and secondary aromatic amines (D2E) are preferred.

In a particularly preferred embodiment, sterically hindered phenols (D2B) and phosphorus compounds are used. The antioxidant (D2) can be used in a proportion of 0.01 to 10% by weight. A total content of up to 2% by weight is preferred.

Ciba is particularly preferred1010 and126.

As stabilizers for improving the hydrolysis resistance, the molding compositions of the invention may comprise hydrolysis stabilizers (D3), i.e.one or more substances selected from the group consisting of (D3A) glycidyl ethers or (D3B) carbodiimides. Examples are ethylene glycol, propylene glycol, 1, 4-butanediol, 1, 3-butanediol, mono-, di-or optionally polyglycidyl ethers of glycerol, and trimethylolpropane triglycidyl ether. The proportion of the stabilizer (D3) mentioned may be from 0 to 3% by weight. A total content of up to 1.0% by weight is preferred. Polymeric or monomeric carbodiimides are particularly preferred.

As stabilizers (D4) for improving the resistance to acid hydrolysis, the molding compositions of the invention may comprise acid-extractable substances, i.e.one or more substances selected from the group consisting of nitrogen-containing compounds (D4A), alkaline earth metal compounds (D4B) or bases (D4C).

If the substrate comprises polyacetal or a similar acid-labile polymer, in a preferred embodiment not only a nitrogen-containing compound (D4A) but also an alkaline earth metal compound (D4B) is used.

Examples of the nitrogen-containing compound (D4A) are melamine, melamine-formaldehyde adducts and methylolmelamines.

Examples of alkaline earth metal compounds (D4B) are calcium propionate, tricalcium citrate and magnesium stearate.

An example of a base (D4C) is Na₂CO₃And NaHCO₃。

The preferred use ratio of the acid scavenger (D4) mentioned is 0.001-1.0 wt%. Acid scavengers in the form of mixtures may also be used.

As lubricants (D5) or mold release aids (D6), the molding compositions of the invention may comprise waxes, for example polyethylene waxes and/or oxidized polyethylene waxes, their esters and amides or fatty acid esters or fatty acid amides.

Preferred are mixtures of ethylene bis (fatty acid amides) and montan wax glycerides.

The preferred proportion of lubricant (D5) and demolding aid (D6) used is 0.01 to 10% by weight. A total content of 0.05 to 3 wt.% is particularly preferred. Lubricants may also generally function as mold release aids, and vice versa.

As the colorability additive (D7), the molding compositions of the invention may comprise colorable substances, so-called colorants. They may be organic or inorganic pigments, as well as dyes.

There is no particular limitation on the pigment and the dye. However, pigments which are homogeneously distributed in the molding composition and which are not enriched at the interface or individual microdomains should be used, so that excellent color uniformity, color constancy and mechanical properties can be ensured.

By way of example, mention may be made of anthraquinone dyes and various pigments, such as carbon black, azo pigments, phthalocyanine pigments, perylene pigments, quinacridone pigments, anthraquinone pigments, indoline pigments, titanium dioxide pigments, iron oxide pigments and cobalt pigments. Any desired suitable combination of colouring substances may also be used within the present invention. If carbon-carbon blacks are used, it is frequently observed that they contribute to stabilization against weathering in addition to the color action.

The content of the coloring matter is preferably 0.05 to 10% by weight in total, particularly preferably up to 5% by weight. If the content is too low, the desired color depth is often not achieved; higher contents are in most cases unnecessary and economically unattractive and may impair other properties, such as the mechanical properties of the molding compositions.

As crystallization-regulating substances (D8), the molding compositions according to the invention may comprise homogeneous or heterogeneous nucleating agents, i.e.one or more substances selected from solid inorganic compounds and crosslinked polymers. (D8) Examples of nucleating agents are fumed silica, calcium fluoride, sodium phenylphosphinate, alumina, finely divided polytetrafluoroethylene, antimony white, pyrophyllite, dolomite, melamine cyanurate, boron compounds such as boron nitride, silicic acid, montmorillonite, and also organically modified montmorillonite, organic and inorganic pigments, melamine-formaldehyde condensates and phyllosilicates, with and without surface modification.

In a preferred embodiment, the inventive molding compositions comprise talc or branched or partially crosslinked polymers as nucleating agents.

The nucleating agent is preferably used in a proportion of 0.0001 to 5 wt%. A total content of 0.001 to 2.0 wt.% is preferred.

The inventive molding compositions may furthermore comprise additives (D9), which have a favorable effect on the combustion behavior. Any known flame retardants may be used, both those containing halogen and those containing no halogen.

A total content of 0 to 30% by weight is preferred.

Examples of flame retardants are (D9A) nitrogen-containing flame retardants, (D9B) phosphorus-containing flame retardants in which the oxidation state of phosphorus is from +5 to-3), (D9C) antimony trioxide (often in combination with halogen-containing synergists), (D9D) halogen-containing compounds, and (D9E) low-halogen content or halogen-free formulations.

Examples of D9A or D9B are melamine polyphosphate, melamine cyanurate, resorcinol diphosphate, polyhalobiphenyl, polyhalodiphenyl ether, polyhalophthalic acid and its derivatives, polyhalooligo-and polycarbonates, substituted phosphines such as triphenylphosphine, substituted phosphine oxides, melamine phosphates, phosphinites and the corresponding salts, elemental phosphorus, hypophosphites and the corresponding salts, phosphites and the corresponding salts, phosphates and the corresponding salts.

The inventive molding compositions may furthermore comprise additives (D10) which have a favorable effect on the mechanical properties as impact modifiers.

A total content of 0 to 20% by weight is preferred.

Examples of these are particulate polymers, which are often rubber-elastic or contain rubber-elastic components.

Preferred types of these elastomers are the so-called ethylene-propylene (EPM) or ethylene-propylene-diene (EPDM) rubbers. EPM rubbers generally have almost no more double bonds, whereas EPDM rubbers may have from 1 to 20 double bonds per 100 carbon atoms.

Examples which may be mentioned of diene monomers for EPDM rubbers are conjugated dienes, such as isoprene and butadiene, non-conjugated dienes having from 5 to 25 carbon atoms, such as 1, 4-pentadiene, 1, 4-hexadiene, 1, 5-hexadiene, 2, 5-dimethyl-1, 5-hexadiene and 1, 4-octadiene, cyclic dienes, such as cyclopentadiene, cyclohexadienes, cyclooctadienes and dicyclopentadiene, and alkenyl norbornenes such as 5-ethylidene-2-norbornene, 5-butylidene-2-norbornene, 2-methallyl-5-norbornene, 2-isopropenyl-5-norbornene, and tricyclodienes, such as 3-methyl-tricyclo [5.2.1.0.2.6] -3, 8-decadiene or mixtures thereof.

1, 5-hexadiene-5-ethylidenenorbornene and dicyclopentadiene are preferred.

The diene content of the rubber is preferably from 0.5 to 50% by weight, in particular from 1 to 8% by weight, based on the total weight of the EPDM rubber.

The EPM or EPDM rubbers may also preferably be grafted with reactive carboxylic acids or their derivatives. Examples thereof may be mentioned acrylic acid, methacrylic acid and derivatives thereof, such as glycidyl (meth) acrylate, and maleic anhydride.

Copolymers of ethylene with acrylic acid and/or methacrylic acid and/or esters of these acids are another preferred class of rubbers. The rubber may also contain dicarboxylic acids, such as maleic acid and fumaric acid, or derivatives of these acids, such as esters and anhydrides, and/or monomers containing epoxy groups. These dicarboxylic acid derivatives or monomers comprising epoxy groups are preferably incorporated into the rubber by adding monomers comprising dicarboxylic acid groups or epoxy groups.

Preferred elastomers are also emulsion polymers, the preparation of which is described, for example, by Blackley in the monograph "emulsion polymerization". Emulsifiers and catalysts which can be used are known per se. In principle, homogeneously composed elastomers or those having a shell structure can be used. The shell-type structure is determined by the order of addition of the individual monomers; the morphology of the polymer is also affected by this order of addition. As monomers for preparing the rubber part of the elastomer, mention may be made here only representatively of acrylates such as n-butyl acrylate and 2-ethylhexyl acrylate, the corresponding methacrylates, butadiene and isoprene, and also mixtures thereof. These monomers may be copolymerized with other monomers, such as styrene, acrylonitrile, vinyl ethers, and other acrylates or methacrylates, such as methyl methacrylate, methyl acrylate, ethyl acrylate, or propyl acrylate. The soft or rubbery phase of the elastomer (having a glass transition temperature below 0 ℃) may be the core, the outer shell or an intermediate shell (when the elastomer has a structure with more than two shells); for elastomers having multiple shells, the multiple shells may also be composed of a rubber phase. If the structure of the elastomer comprises, in addition to the rubber phase, one or more hard components (having a glass transition temperature above 20 ℃), they are generally prepared by polymerizing styrene, acrylonitrile, methacrylonitrile, alpha-methylstyrene, p-methylstyrene, acrylates and methacrylates, such as methyl acrylate, ethyl acrylate and methyl methacrylate, as the main monomers. In addition to these monomers, it is also possible to use smaller proportions of other comonomers.

The particles of the rubber phase may also be crosslinked. Examples of monomers which act as crosslinkers are 1, 3-butadiene, divinylbenzene, diallyl phthalate and dihydrodicyclopentadienyl acrylate, and also the compounds described in EP-A50265.

It is also possible to use so-called graft-linking monomers, i.e. monomers having two or more polymerizable double bonds which react at different rates during the polymerization. Preference is given to using compounds in which at least one reactive group polymerizes at almost the same rate as the remaining monomers, while the other reactive group or groups polymerize, for example, at a significantly slower rate. The different polymerization rates result in a certain proportion of unsaturated double bonds in the rubber. If a further phase is then grafted onto such a rubber, the double bonds present in the rubber react at least partially with the grafting monomers to form chemical bonds, i.e.the grafted-on phase is at least partially connected to the graft base via chemical bonds.

Examples of such graft-crosslinking monomers are monomers comprising allyl groups, especially allyl esters of ethylenically unsaturated carboxylic acids, such as allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate and diallyl itaconate, and the corresponding monoallyl compounds of these dicarboxylic acids. In addition to these compounds, a large number of other suitable graft-crosslinkable monomers are present.

It is also possible to use homogeneous, i.e. single-shell, elastomers composed of 1, 3-butadiene, isoprene and n-butyl acrylate or copolymers thereof instead of graft polymers having a multishell structure. These products can also be prepared by using crosslinking monomers or monomers having reactive groups simultaneously.

Examples of preferred emulsion polymers are n-butyl acrylate- (meth) acrylic acid copolymers, n-butyl acrylate-glycidyl acrylate or n-butyl acrylate-glycidyl methacrylate copolymers, graft polymers having an inner core composed of n-butyl acrylate or based on butadiene and having an outer shell composed of the abovementioned copolymers, and copolymers of ethylene with comonomers which provide reactive groups.

The elastomers may also be prepared according to other conventional methods, for example by suspension polymerization.

Other preferred rubbers are polyurethanes, polyetheresters and silicone rubbers.

It is, of course, also possible to use mixtures of the types of rubbers listed above.

As fillers and reinforcing agents (D11), the thermoplastic molding compositions according to the invention may comprise fibrous, lamellar or particulate fillers and reinforcing agents.

Examples are carbon fibers, aramid fibers, glass beads, amorphous silica ((R))) Asbestos, calcium silicate (wollastonite), aluminium silicate, magnesium carbonate, kaolin, chalk, lime, marble, powdered quartz, mica, barite, feldspar, phyllosilicates and aluminosilicates, bentonite, montmorillonite and talc.

The filler may have been modified via an organic component or silanization. The proportion of these fillers is generally up to 50% by weight, preferably up to 35% by weight.

The novel molding compositions may furthermore comprise additives (D12) which influence the mobility of the chains in the amorphous phase or reduce the glass transition temperature or otherwise act as plasticizers.

Examples are dioctyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, hydrocarbon oils, N- (N-butyl) benzenesulfonamide and o-and p-tolylethylsulfonamide.

The molding compositions according to the invention may comprise, as further additives (D13), additives which ensure or improve the functional properties (e.g.conductivity and/or antistatic behavior) of the molding compositions according to the respective prior art.

An example of a way of preparing the molding compositions according to the invention or suitable intermediates is to mix all the ingredients in a device with good mixing action, such as a Brabender, extruder, preferably a twin-screw extruder, or on mixing rolls, at elevated temperature, i.e.at a temperature above the melting point of the matrix polymer (A), some or all of the matrix polymer (A).

Alternatively, the components are mixed at room temperature and the matrix polymer is subsequently melted in an extruder, preferably a twin-screw extruder.

Another way of preparation is possible if the matrix a comprises a polymer formed by polycondensation: in this case, the additives can be added already during the molecular weight build in order to achieve better dispersion. This variant has advantages, in particular for nanoscale additives C. These and other components may be added at the end of the transesterification reaction or at the beginning of the polycondensation reaction if the matrix comprises a polyester.

It is likewise possible for the individual components, individually or in combination, to be first processed to give relatively highly concentrated masterbatches, which are then further processed with the other components to give the mixtures of the invention.

The additives mentioned within the scope of the present description may be added in any desired suitable step. The final formulation of the molding composition can also be prepared by: the additive or additives are not added until shortly before the molded article is produced. It is also suitable to mix the granules with an additive paste or to mix two or more types of granules, at least one of which corresponds to the molding composition of the invention, or which ultimately together give the composition of the invention.

The molding compositions according to the invention are thermoplastic and therefore suitable for conventional processing.

The processing is generally carried out by using pellets, which are further processed in a known manner, for example via extrusion, injection molding, vacuum forming, blow molding or foaming, to give molded articles.

The molding compositions according to the invention are suitable as engineering materials for the production of semifinished products and finished parts. The present invention also provides molded articles in irradiated and unirradiated form, which are prepared from the molding compositions according to the invention by conventional processing techniques, in particular by injection molding. The molded articles of the present invention can be used in the computer industry, the electrical industry, the electronic industry, the household product industry and the automotive industry.

Marking and inscribing of the inventive moldings, for example keyboards, cables, lines, decorative strips or functional parts in the heating, ventilation and cooling zones, or switches, plugs, levers and handles, comprising the inventive molding compositions can be achieved by means of lasers.

The molded articles of the invention can furthermore be used as packaging.

The invention furthermore provides a method for laser marking of a thermoplastic plastic moulded article, comprising the following steps:

i) preparation of moulded articles from a moulding composition as defined above comprising at least one partially crystalline thermoplastic A) and components B) and/or C) and D), and

ii) irradiating a predetermined portion of at least one surface of the molded article with a laser to cause a change in appearance of the irradiated portion.

The present invention likewise provides the use of the above-defined components B) and/or C) for laser marking molded articles.

The markings obtained thereby are characterized in that they are resistant to wiping and scratching, stable during subsequent sterilization and can be applied in a marking process under hygienically clean conditions.

Another field of application for laser inscription is plastic markers for the individual identification of animals, so-called poultry rings, livestock tags or ear tags. The inscription must be very durable because some markers remain on the animal for many years.

Detailed Description

The invention is illustrated by the following examples. And are not intended to be limiting.

Examples

Test specimens comprising Polyoxymethylene (POM) or polybutylene terephthalate (PBT) as partially crystalline engineering thermoplastic (a) were prepared and tested.

In addition to component a, embodiments of the present invention include a photosensitive compound (B) having a plurality of cations, or nanoscale particles (C) of a photosensitive oxide, or a combination of both. In contrast, the samples considered as comparative examples comprise micron-sized particles of a photosensitive compound having a cation, or a photosensitive oxide, or act as a reference without a photosensitive additive.

The following table lists the compositions of the samples.

If the examples contain the recording (Eintrag) POM as component A, the substrate used isC9021 polyoxymethylene (Ticona GmbH).

Conventional additives D used_POMIs that1010(Ciba) as an antioxidant,234 and770 (each from Ciba)GmbH) as light stabilizer,C (clariant gmbh) as flow and release aids, and melamine and calcium propionate as acid extractants.

If the examples contain the PBT record as component A, the substrate used is PBT2003(Ticona GmbH)。

Conventional additives D used_PBTIs that1010 and126 (each from Ciba)GmbH) as an antioxidant, talc as a nucleating agent,WD4(Clariant GmbH) as flow aid and mold release aid, and(Rheinchemie Rheinau GmbH) as a moisture extractant.

If the examples contain the recording of CuOHP as component B, copper (II) hydroxide phosphate from Aldrich or Chemische Fabrik Budenheim KG was used.

If the examples contain recording FeP as component B, additive powders which contain both iron (II) and iron (III) as cations are used. The material purchased and used was iron (II) phosphite containing small amounts of iron (III) ions and phosphate, available from Chemische Fabrik Budenheim KG.

If the examples contain the recording CuFeP as component B, additive powders which contain not only copper (II) but also iron (II) and iron (III) as cations are used, which are available from the company Chemische Fabrik Budenheim KG. To prepare the molding compositions, the additives were used in the following form: as an unreacted mixture of individual salts (approximately 50% copper (II) hydroxide phosphate with approximately 50% iron (II) phosphite), and as a reacted mixed salt. The diffraction spectra obtained from the test of the moulding compositions with X-rays differ significantly from those of the simple starting salts.

If the examples contain the recording SnCuP as component B, additive powders comprising both tin (II) and copper (II) as cations are used, which are available from the company Chemische FabrikBudenheim KG. To prepare the molding compositions, the additives were used in the following form: as an unreacted mixture of individual salts (about 80% tin (II) phosphate with about 20% copper (II) hydroxide phosphate) or as a reacted mixed salt. The diffraction spectra obtained using X-ray testing on the molding compositions differed significantly from those of the simple starting salts.

If the examples contain the recording CuSbP as component B, additive powders which contain both copper (II) and Sb (III) as cations are used, which are available from the company Chemische Fabrikheim KG. To prepare the molding compositions, the additives were used in the following form: the individual salts are in the form of an unreacted mixture (about 80% antimony (III) phosphate with about 20% copper (II) hydroxide phosphate). The diffraction spectra obtained using X-ray testing on the molding compositions differed significantly from those of the simple starting salts.

If the examples contain recording nano TiO₂(n-TiO₂) As component C, titanium dioxide having a particle size of a few nanometers is used, for example P25 from Degussa or Hombitec RM130F from Sachtleben.

The introduction of these additives in the form of nanoparticles and the substantial avoidance of larger agglomerates is sought by introduction under high shear and in the lower molecular weight prepolymers.

If the comparative example contains the recording of μ -TiO₂As component D7, 1% of a polymer having D is used₅₀A titanium dioxide white pigment of 0.3 μm, for example, from Kronos corporation under the designation 2078 or 2220.

The molding compositions were compounded in a twin-screw extruder (Berstorff ZE-25) having two kneading blocks. In the presence of nano TiO₂In the case of the molding compositions of (1), the nanoadditive is already added during the polycondensation reaction.

The molding composition was then injection-molded to obtain sheets having dimensions of 90mm by 65mm by 1 mm.

Obtained from ACI Laser GmbH (Th ü ringer) DPL Magicmarker from company for laser scribing and the scribing parameters were varied as follows:

the pump intensity is 40-90%, the pulse frequency is 1-6kHz, and the horizontal feed rate and vertical line fill are selected to achieve cube patterns of 40, 50 and 75 μm.

To determine the optical properties of the substrate and the indicia, a Colorview II digital camera, including the analySIS Pro image evaluation software from Soft Imaging Systems, was used, mounted on a BX51 microscope from Olympus.

To determine the lightness and darkness values (along the white-black L)^*Axis) microscopic images were recorded under maximum reflected light and converted to grayscale images and averaged over the entire recording range. This method was used to obtain digital quantitative data from 0 ("black") to 255 ("white"). All samples were recorded under the same lighting conditions. In each caseNext, the substrate and the laser mark were recorded and evaluated separately.

For determining the color values, microscopic images were recorded at maximum reflection, averaged over the entire recording range and read for the red, green and blue components. This method is used to obtain digital quantitative data from 0-255 for the three primary color components. All samples were recorded under the same lighting conditions. In each case, the substrate and the laser mark were recorded and evaluated separately.

The results were used as the basis for the collated information in the tables.

If the examples are evaluated as "good" (+) in the light sensitivity column, sufficient contrast in the marked area has been obtained with a pump intensity of less than or equal to 50% and a pulse frequency of more than 4 kHz.

If the examples were evaluated as "under" (-) in the photosensitivity column, no sufficient contrast was obtained in the mark region with a pump intensity of less than or equal to 50% and a pulse frequency of greater than 4 kHz.

If the example is evaluated as "medium" (0) in the light sensitivity column, the result is located between the two.

If the examples were evaluated as "good" (+) in the brightness column for the substrate, the brightness value for the PBT substrate was greater than 222 or the POM substrate was greater than 220.

If the examples were evaluated as "insufficient" (-) in the luminance column for the substrate, the luminance value for the PBT substrate was less than 220 or the luminance value for the POM substrate was less than 216.

If the example is rated "medium" (0) in the matrix brightness column, the result is in-between.

If the example is evaluated as "white", "light" or "light gray" in the column for the matrix color, the red-green-blue components are substantially equal, in the case of "cyan" the intensity recorded in the green-blue region is slightly greater, and in the case of "reddish" the intensity recorded in the red is slightly greater.

If the example evaluates to "good" (+) in the darkness column of the mark, the darkness value of the mark (255-lightness) is greater than 80.

If an example evaluates to "less than" (-) in the darkness column of the mark, the darkness value of the mark is less than 50.

If an example evaluates to "medium" (0) in the darkness column of the mark, the result is in-between.

If the example evaluates in the column of marking colors as "black", "anthracite (anthracite)" or "black-gray", the red-green-blue components are substantially equal, in the case of "black-brown" the intensity recorded in the red-green or red-blue region is slightly greater, and in the case of "black-red" the intensity recorded in red is slightly greater.

If the example is evaluated as "good" (+) in the contrast column, the ratio of substrate brightness/mark brightness is greater than 1.25.

If the example is evaluated as "insufficient" (-) in the contrast column, the ratio of substrate luminance/mark luminance is small.

If the examples were rated "good" (+) in the column of mark morphology, there was no appreciable local roughness increase (not craters or recesses or foamed bumps) at the mark site.

If the examples were rated "under" (-) in the column of the mark morphology, there was a clearly perceptible local roughness increase (not craters or recesses or foamed bumps) at the marked sites.

If an example evaluates to "medium" (0) in the flag shape column, the result is in between.

From the tables, it can be seen that the molding compositions according to the invention do not have an inadequate assessment of laser inscription, whereas all comparative examples have at least one criterion classified as inadequate.

Comparative example is represented by "V"; embodiments of the present invention are represented by numerical data.

Claims (15)

1. Laser-markable molding compositions comprising

A) At least one partially crystalline thermoplastic and

B) at least one particulate photosensitive salt-type compound comprising two or more cations, wherein the two or more cations are derived from different elements, wherein one cation is selected from the group consisting of: ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ag, Sn, Sb, La, Pr, Ta, W, Ce, wherein another cation is selected from: elements of the main groups 3 to 6 of the II and III of the periodic Table of the elements, elements of the main groups 5 to 6 of the IV of the periodic Table of the elements and elements of the subgroups 4 to 5 of the III to VIII of the periodic Table of the elements and lanthanides, and/or

C) At least one particulate inorganic oxide having an average particle size of less than 250 nm.

2. Moulding compositions according to claim 1, characterized in that component B has an average particle size d of less than 10 μm₅₀。

3. Moulding compositions according to claim 1, characterized in that component B contains, in addition to two different cations selected according to claim 1, a cation of an element selected from the group I of the 2 nd to 5 th periods.

4. Moulding compositions according to claim 1, characterized in that the proportion by weight of component A) is from 50 to 99.95% by weight, based on the total weight of the moulding composition.

5. Moulding compositions according to claim 1, characterized in that component A) is selected from the group consisting of polyacetals, polyesters, polyamides, polyarylene ethers, polyarylene sulfides, polyether sulfones, polysulfones, polyaryl ether ketones, polyolefins, liquid-crystalline polymers and combinations comprising one or more of these polymers.

6. Moulding compositions according to claim 1, characterized in that component B) comprises inorganic oxoanions, anions of organic carboxylic acids or anions of carbonic acid as anions.

7. Moulding compositions according to claim 6, characterized in that component B has phosphorus-containing oxyanions as anions.

8. A molding composition according to claim 6, characterized in that component B) has the formula A_aO_o(OH)_y ^Z-Wherein a is tri-or pentavalent phosphorus, tetra-or hexavalent sulfur, tetravalent molybdenum or hexavalent tungsten, a, o and z are, independently of one another, integers having a value of 1 to 20, and y is an integer having a value of 0 to 10.

9. Moulding compositions according to claim 1, 6 or 8, characterized in that component B) has a combination of two different elements selected from the group consisting of copper, tin, antimony and iron as cations.

10. Moulding compositions according to claim 1, characterized in that component C) has an average particle diameter of less than 200 nm.

11. Moulding compositions according to claim 1, characterized in that the refractive index of component C) is different from the refractive index of component A).

12. Moulding compositions according to claim 1, characterized in that the inorganic oxide (C) is chosen from: al (Al)₂O₃、SiO₂Silicate or aluminosilicate minerals, silicate glasses, TiO₂、ZnO、ZrO₂、SnO₂、Sb₂O₃、Sb₂O₅、Bi₂O₃And mixed oxides thereof with other doping elements.

13. Moulding compositions according to claim 1, characterised in that they contain at least one sterically hindered phenol together with a phosphorus compound as additive.

14. A method of laser marking a thermoplastic molded article comprising the steps of:

i) preparation of a molded article from the molding composition according to any of claims 1 to 13 comprising at least one partially crystalline thermoplastic A) and components B) and/or C), and

ii) irradiating a predetermined portion of at least one surface of the molded article with a laser to cause a change in appearance of the irradiated portion.

15. A molded article obtainable by shaping a molding composition according to any of claims 1 to 13.