KR102171893B1 - Additive for lds plastics - Google Patents

Abstract

The present invention relates to an article having an LDS-active additive for LDS plastics, a polymer composition containing the additive, and a metallized conductor track containing an LDS additive of this type, a polymeric base of the article or a polymeric coating on the base. will be.

Description

Additive for LDS plastics {ADDITIVE FOR LDS PLASTICS}

The present invention relates to the use of a composite pigment consisting mainly of titanium dioxide and antimony-doped tin dioxide as an LDS-active additive for LDS plastics, and in particular as an LDS additive in a polymer composition used in the LDS process, an additive of this type. A polymeric composition comprising, and a polymeric base body of the article, or a polymeric coating on the base body, relates to an article having a metallized conductor track comprising an LDS additive of this type.

Three-dimensional plastic parts with circuits, the so-called MIDs (molded interconnect elements), have gained their own recognition in the market for many years, and for many applications, for example, in telecommunications, automobile construction or medical technology. Contributed decisively to facilitation. At the same time, this has contributed significantly to the miniaturization and complexity of the individual electronic components in the agent.

Various methods of manufacturing three-dimensional MIDs exist, whereby a basic part comprising a plastic or having a plastic-containing coating obtained, for example by two-component injection molding or hot embossing, together with the essential circuit structure. Is provided. In general, this requires special product-specific molds, which are expensive to purchase and inflexible to use.

In contrast, the LDS process (laser direct structuring process) developed by LPKF is a plastic base part or plastic-containing coating on the base part by means of a laser beam in a manner in which the circuit structure is directly and individually adapted. It offers a decisive advantage that it can be cut with water and then metallized.

A simpler process, for example a one-component injection-molding process, is suitable for the manufacture of a plastic base, and the cutting of the circuit structure can also be controlled three-dimensionally.

In order to be able to obtain a circuit structure that can be metallized by means of a laser beam, so-called LDS additives have to be added to the plastic base or the plastic-containing coating. These additives must react to the laser radiation and at the same time prepare for subsequent metallization. The LDS additive is a metal compound that is activated during processing with a laser beam in the laser-treatment area, in a way that the metal nuclei are usually free (which favors the subsequent deposition of electrically conductive metal for the formation of an electrical circuit at the point of activation of the plastic). Includes. At the same time, these metal compounds react laser-actively (generally laser-absorbing), and ensure that the plastic is removed and carbonized in the laser-treated area so that the circuit structure is etched into the plastic base. The metal compound remains unchanged at the point of the plastic that was not activated by the laser. The LDS additive is added to the plastic material as a whole prior to shaping to yield the plastic base, or alternatively only the circuit structure is cut by a laser beam as a component into a separate plastic-containing layer, coating, paint layer, etc. It can only exist on the surface.

In addition to future circuit structures containing metal nuclei, when processed by laser beams, a microrough surface also occurs within the circuit structure, which can fix itself to the plastic with strong adhesion during subsequent metallization. This is a prerequisite for a conductive metal, usually copper.

The metallization is generally then carried out in a no-current copper bath, which may likewise be followed by further application of nickel and gold layers in a no-current bath. However, other metals such as tin, silver and palladium can also optionally be applied, for example with gold. The plastic parts pre-structured in this way are then fitted with individual electronic parts.

The purpose of the LDS process consists in creating a three-dimensional electrically conductive circuit structure on a three-dimensional plastic base body or on a base body with a plastic-containing coating. For this purpose, it goes without saying that only the resulting metallized circuit structure can be electrically conductive, and not the plastic base body or coating itself. Thus, LDS additives proposed in the past are generally additives that do not themselves have electrical conductivity and do not impart electrical conductivity on the base material.

Originally, in particular non-conductive organic heavy metal complexes containing palladium (EP 0 917 597 B1) were intended as LDS additives.

In EP 1 274 288 B1, non-conductive inorganic metal compounds which are insoluble in the application medium and are inorganic metal compounds of metals and nonmetals of groups d and f of the periodic table are added to plastics as LDS additives. It is preferred that a copper compound, in particular a copper spinel, is used.

However, organic Pd complexes or also copper spinels have the advantage that they have a dark intrinsic color itself and also impart a dark color on the plastics containing it. In addition, the copper compound particularly affects the partial deterioration of the plastic material surrounding it. However, especially in the case of MIDs used in telecommunications, they have a pale intrinsic color, so that the efficacy of the LDS additive is adversely affected or weakened, the increase in plastics that can be colored in any desired shade without the need to add colored pigments in a large weight ratio. There is a demand. Also, deterioration of the plastic base is not desirable.

In order to produce plastics with a pale intrinsic color usable for the LDS process, EP 2 476 723 A1 accordingly proposed tectoalumosilicate (zeolite) as an LDS additive for plastics.

WO 2012/126831 discloses a corresponding LDS process in which an LDS additive comprising plastics suitable for LDS and antimony-doped tin dioxide and having an L ^* value of 45 or higher (luminescence) in the CIELab color space is added. Mica coated with antimony-doped tin dioxide is preferably used in an amount of 2 to 25% by weight, based on the total plastic material. In addition, white colored pigments can also be added for a uniform lighter coloring of the plastic material.

WO 2012/056416 also discloses a composition comprising 0.5 to 25% by weight of a metal oxide-coated filler, wherein the latter is preferably mica coated with antimony-doped tin dioxide. The LDS plastic material has an L ^* value of 40 to 85. Colored pigments can also be added to the plastic material.

Mica flakes coated with antimony-doped tin dioxide are generally used as electrically conductive pigments in a wide variety of applications where, for example, plastic materials are provided with antistatic properties. The pigment of the composition also serves as an additive for plastics provided with laser engraving, which allows mica coated with antimony-doped tin dioxide to absorb normal laser radiation and the stored heat passes through the plastic material surrounding the pigment and blackens it. . The use of mica coated with antimony-doped tin dioxide as an LDS additive in the corresponding plastic material suitable for LDS can thus also yield the formation of a conduction path if the critical usage concentration is exceeded. However, conductive plastics are less suitable for use in the LDS process, which can significantly impair the electrical conductivity of the circuit structure applied to the plastic base and also the MID obtained is subject to strict requirements for its dielectric properties. This is because it is not suitable for mobile phones that have electronic components for use in certain high-frequency applications (HF applications), integrated antennas or WLAN systems that are applied to.

In order to obtain a plastic with a sufficiently good dielectric value in a polymeric material suitable for the LDS process and whereby an electronic component suitable for HF can be obtained, for example in US 8,309,640 B2 having a dielectric constant of 25 or more measured at 900 MHz. It is proposed to add ceramic fillers to thermoplastics in addition to suitable LDS additives. However, since the LDS additives used here are the common copper compounds already mentioned above, these LDS-compatible plastics, however, are dark-colored in black despite having good dielectric values.

Therefore, there is still a demand for plastics that are suitable for LDS processes, have a pale intrinsic color and also have sufficiently high dielectric values in polymeric materials that they can be used in high frequency applications. In particular, there has been a demand for LDS additives suitable for plastics. Naturally, all other requirements of the LDS additive, namely the ability to be activated by laser radiation, the liberation of the metal nuclei by laser bombardment, and the formation of a microrough surface by the laser beam as a basis for subsequent metallization, have to be satisfied here.

Accordingly, it is an object of the present invention to make it possible to manufacture a pale LDS plastic that can be easily colored by using a small amount of a chromatic colorant mixture through its pale intrinsic color, and impart a dielectric or only the slight electrical conductivity properties to the provided plastic. (Such plastics are suitable for high-frequency applications) and, if possible, prevent deterioration of the surrounding plastic matrix, and also a good metal of circuit structure obtainable in the LDS process when using the widest possible-bandwidth of laser parameters. It consists in providing an LDS additive for LDS plastics that enables conversion.

A further object of the present invention consists in providing a polymeric composition suitable for the LDS process and having the properties described above.

A further object of the present invention consists in providing an article having a circuit structure manufactured in an LDS process and having the above-mentioned properties.

An object of the present invention is 80% by weight or more of titanium dioxide (TiO ₂ ) and antimony-doped tin dioxide ((Sb,Sn)O ₂ based on the total weight of the composite pigment as an LDS additive (laser direct structuring additive) in a polymeric composition. ).

The object of the present invention is also achieved by a polymeric composition comprising at least one organic polymeric plastic and LDS additive, wherein the LDS additive is at least 80% by weight of titanium dioxide (TiO ₂ ) and antimony based on the total weight of the composite pigment. -It is a complex pigment composed of doped tin dioxide ((Sb,Sn)O ₂ ).

It is also an object of the present invention to have a circuit structure manufactured by the LDS process, consisting of a base body of an article having a polymeric base body or a polymer-containing coating of the article and a metallic conductor track disposed on the surface of the base body. Achieved by the article, wherein the polymeric base body or polymer-containing coating of the base body is at least 80% by weight of titanium dioxide (TiO ₂ ) and antimony-doped tin dioxide ((Sb,Sn) based on the total weight of the complex pigment. It contains an LDS additive composed of a complex pigment composed of )O ₂ ).

The complex pigments, which consist essentially of titanium dioxide (TiO ₂ ) and antimony-doped tin dioxide ((Sb,Sn)O ₂ ), are themselves, in particular titanium dioxide cores and coatings present on the core, antimony-doped tin dioxide. It is known in the form of a pigment made. These pigments may optionally also have interlayers and/or protective layers between the core and the (Sb,Sn)O ₂ coating. Pigments of this type, in which the TiO ₂ core can have various geometries, have long been used as antistatic agents in coatings and plastics. It has electrical conductivity itself and likewise imparts electrical conductivity to the plastic or coating comprising it in sufficient concentration. In order to increase this electrical conductivity, pigments in which the TiO ₂ core is needle-shaped have been developed particularly recently.

Surprisingly, however, it has now been found that complex pigments consisting of at least 80% by weight of TiO ₂ and antimony-doped tin dioxide, based on the total weight of the complex pigment, are very suitable as LDS additives in polymeric compositions.

Accordingly, the present invention relates to the use of such composite pigments as LDS additives in polymeric compositions for use in LDS processes.

The composite pigments used according to the invention have at least one core and a coating arranged on the core. The coating may consist of one or more individual layers.

In the simplest case, the coating consists of a single, functional layer. In addition, the coating may have one or more interlayers between the core and the functional layer and/or may also have one or more protective layers on the surface of the functional layer.

When a single composite pigment particle consists of only a single core and a coating disposed on the core, the composite pigment used according to the invention consists exclusively of the primary particles and is thus monodisperse. However, more frequent and thus preferred are embodiments in which the composite pigments used are an aggregate of two or more primary particles, wherein each primary particle has a core and a coating arranged on the core.

According to the invention, the primary particles are in the order of the layer structure of the core/functional layer, the layer structure of the core/interlayer(s)/functional layer, the layer structure of the core/functional layer/protective layer(s) or the core/interlayer ( All composite pigments having a layer structure of)/functional layer/protective layer(s) can be used. According to the invention, the core or functional layer consists of TiO ₂ or antimony-doped tin dioxide.

Since the core and functional layers in one and the same composite pigment or primary particle are not naturally composed of the same material, the composite pigment used according to the invention may have the following composition:

TiO ₂ core/(Sb,Sn)O ₂ layer,

TiO ₂ core/interlayer(s)/(Sb,Sn)O ₂ layer,

TiO ₂ core/(Sb,Sn)O ₂ layer/protective layer(s),

TiO ₂ core/interlayer(s)/(Sb,Sn)O ₂ layer/protective layer(s),

(Sb,Sn)O ₂ core/TiO ₂ layer,

(Sb,Sn)O ₂ core/interlayer(s)/TiO ₂ layer,

(Sb,Sn)O ₂ core/TiO ₂ layer/protective layer(s),

(Sb,Sn)O ₂ core/interlayer(s)/TiO ₂ layer/protective layer(s).

The proportion by weight of the sum of the core and functional layers, i.e. the sum of TiO ₂ and antimony-doped tin dioxide, is in each case at least 80% by weight, preferably at least 90% by weight, based on the total weight of the composite pigment, in particular 95-100% by weight. This means that the composite pigments used in a particularly preferred embodiment of the invention consist only of TiO ₂ and (Sb,Sn)O ₂ or optionally only very small amounts of other components are present.

Antimony-doped tin dioxide, regardless of whether it is used as a core in a coating of primary particles or as a functional layer, has a percentage ratio by weight of antimony to tin of 2 based on the total weight of antimony and tin. To 35% by weight, preferably 8 to 30% by weight, in particular 10 to 20% by weight.

If interlayers and/or protective layers are present, they are predominantly made of inorganic materials in the case of interlayers. Very suitable interlayers are metal oxides, in particular SiO ₂ , SnO ₂ , Al ₂ O ₃ , ZnO, CaO, ZrO ₂ , Sb ₂ O ₃ , or mixtures thereof.

The protective layer that may be present on the surface of the composite pigment used may, in contrast, be of inorganic or organic nature. This applies in general if the use of complex pigments in the application medium, ie organic polymeric plastics here, is simplified or even made possible by at least a corresponding surface coating. However, this can also be applied to perform any color adaptation desired. In the case of an inorganic protective layer, it is preferably ZrO ₂ , Ce ₂ O ₃ , Cr ₂ O ₃ , CaO, SiO ₂ , Al ₂ O ₃ , ZnO, TiO ₂ , SnO ₂ , antimony-doped SnO ₂ , Sb ₂ O ₃ , or the corresponding oxide hydrate, and mixtures of two or more thereof.

The organic protective layer generally consists of a suitable organosilane, organotitanate or organozirconate. Suitable ingredients are known to those skilled in the art as agents for effective surface coating and post-coating of pigments.

The total proportion by weight of the interlayer(s) and/or the protective layer(s) is here no more than 20% by weight, preferably no more than 10% by weight, particularly preferably no more than 0-5% by weight, based on the total weight of the composite pigment. % to be.

In a preferred embodiment of the present invention, the composite pigment used as the LDS additive consists of only one or more primary particles, which in each case is a core and a functional coating disposed on the core, i.e. a TiO ₂ core and (Sb,Sn) Consisting of an O ₂ coating or a (Sb,Sn)O ₂ core and a TiO ₂ coating; Most preferred, however, is an embodiment in which the composite pigment consists in each case of a TiO ₂ core and primary particle(s) consisting of a (Sb,Sn)O ₂ coating. Optionally, only 5% by weight or less of foreign constituents, based on the total weight of the composite pigment, are present, which may be present in the interlayer and/or the protective layer.

In the composite pigments used according to the invention the core can itself be of any possible shape. However, this has proven to be particularly advantageous with respect to the electrically conductive properties that the composite pigments used according to the invention as LDS additives impart to the polymeric plastics provided therewith so that the core has an isotropic shape in the composite pigments. This is a shape that is almost ideally the same in all directions of the core in terms of the virtual center point, i. This includes the shape of a sphere and a rectangular parallelepiped core and a core having an irregular, compressed granular shape, and also a regular or semi-regular polygon (Platon and Archimedean bodies) having n faces, where n is in the range of 4 to 92.

It goes without saying that the term spherical, rectangular or regular polygon applies here also to a core shape that is not an ideal spherical, ideal rectangular or ideal regular polygon in the geometric sense. Since the core of the composite pigment is produced in an industrial process, technically derived deviations from the ideal geometry, for example in the case of finished edges or slightly different sized surfaces and polyhedra, are also included here.

In the composite pigment used according to the invention, the core has a particle size in the range of 0.001 to 10 µm, preferably 0.001 to 5 µm, in particular 0.01 to 3 µm.

It consists of TiO ₂ or (Sb,Sn)O ₂ , which is commercially available to the indicated size. Thus, for example, TiO ₂ particles are commercially available under the trade names KRONOS (KRONOS Worldwide, Inc.), HOMBITEC (Sachtleben) or Tipaque (Ishihara Corp.). Antimony-doped tin dioxide particles can be purchased, for example, under the names Zelec (Milliken Chemical) or SN (Ishihara Corp.).

On the surface of the core having the size and material composition indicated above, the primary particles of the composite pigment used according to the invention have a coating having a layer thickness in the range of 1 to 500 nm, preferably 1 to 200 nm.

The coating already includes at least one functional layer consisting of TiO ₂ or (Sb,Sn)O ₂ , depending on the material composition of the core, as indicated above. The interlayer(s) or protective layer(s), if present, are likewise included in the coating. The dimensions of the degree stated above with respect to the layer thickness of the coating apply here only to coatings consisting of the functional layers described above and also to coatings having in addition to the functional layers also at least one interlayer and/or protective layer. Layer-thickness in the range of 1 to 100 nm is particularly preferred for coatings consisting only of (Sb,Sn)O ₂ functional layers.

The proportion of the coating is 20 to 70% by weight, based on the total weight of the primary particles, and also 20 to 70% by weight, based on the total weight of the composite pigment. These data relate only to coatings consisting of the functional layers described above and also to coatings comprising in addition to the functional layers also one or more interlayers and/or protective layers.

When the core consists of TiO ₂ , the proportion of the coating comprising or consisting of at least one functional layer of (Sb,Sn)O ₂ is particularly preferably 35 to the total weight of the primary particles or the total weight of the composite pigment. 55% by weight, in particular 40 to 50% by weight.

When the core consists of (Sb,Sn)O ₂ , the proportion of the coating comprising or consisting of at least one functional layer of TiO ₂ is particularly preferably from 45 to the total weight of the composite pigment or the total weight of the primary pigment. 65% by weight, in particular 50 to 60% by weight.

The particle size of the composite pigments used according to the invention ranges from 0.1 to 20 μm, preferably from 0.1 to 10 μm, in particular from 0.1 to 5 μm. Particular preference is given to the use of composite pigments having a particle size in the range of 0.1 to 1 μm with a D ₉₀ value in the range of 0.70 to 0.90 μm.

All particle sizes indicated above can be measured using conventional methods for particle size determination. Particularly preferred is a method for particle size measurement by means of a laser diffraction method in particular, wherein the nominal particle size of the individual particles and also their percentage particle size distribution can advantageously be determined. All particle size measurements performed in the present invention are determined by laser diffraction method using a Malvern 2000 apparatus from Malvern Instruments Ltd., UK under standard conditions of ISO/DIS 13320.

The layer thickness of each coating is measured numerically from SEM and/or TEM images.

The composite pigments used according to the invention are produced by the known process itself. Here, the starting particles used as the core comprise one or more functional layers in one of the above-indicated compositions, but are preferably provided with a coating consisting only of such functional layers. Since the starting material is in each case inorganic, the coating of the core with a functional layer is preferably carried out in an aqueous suspension by means of a subsequent conversion to a metal oxide with precipitation of the respective metal oxide or metal oxide hydrate. The precursor material of the metal oxide to be obtained, generally a metal salt in dissolved form, is added to the aqueous suspension of each core material and precipitates on the core in the form of a metal oxide hydrate, usually at an approximately set pH. The metal oxide hydrate is then converted to the corresponding oxide by treatment at an elevated temperature. Optionally, the coating of the core with the interlayer and/or protective layer to be applied can be carried out in the same way in the case of the inorganic layer. The organic post-coating is likewise carried out by methods customary in the prior art, in particular by contacting the surface of the composite particles with the corresponding organic material in a suitable medium.

The composite pigment used according to the invention is prepared as follows with reference to the example of a TiO ₂ core provided with a functional coating of antimony-doped tin dioxide:

TiO ₂ particles of substantially spherical shape to the desired size are mixed with demineral water to yield a suspension, which is heated to a temperature in the range of 70 to 90° C. with stirring. The pH of the suspension is adjusted to a value in the range of 1.5 to 2.5 with an acid, for example hydrochloric acid. A solution of tin antimony chloride in a solution of hydrochloric acid of the desired composition is added to the suspension while maintaining the pH constant using a base such as sodium hydroxide solution. When the addition is complete, the pH rises to a value of more than 2.5 to 7.0, and stirring is continued. The product is filtered, washed, dried and calcined for 0.5 to 2 hours at a temperature in the range of 500° C. to 900° C. The product can then optionally be sieved. A composite pigment comprising a TiO ₂ core with a coating of (Sb,Sn)O ₂ is obtained.

The coating of (Sb,Sn)O ₂ core particles with TiO ₂ can be carried out in an aqueous suspension at a pH ranging from 1.5 to 2.5 using a suitable titanium salt, for example TiCl ₄ , in a similar process.

The described composite pigments are present in each polymeric composition as an LDS additive in an amount of 0.1 to 30% by weight, preferably 0.5 to 15% by weight, in particular 1 to 10% by weight, based on the total weight of the polymeric composition in each case. do. It can also be used in polymeric compositions suitable for LDS in mixtures with other LDS additives known from the prior art. In the latter case, the proportion of the LDS additive according to the invention is reduced to that of the other LDS additive(s). Overall, the proportion of the LDS additive is generally not more than 30% by weight as indicated above, based on the total weight of the polymeric composition suitable for LDS.

The polymeric composition is preferably a thermoplastic polymeric composition composed of a predominant proportion (generally more than 50% by weight) of a thermoplastic resin.

Suitable thermoplastics are amorphous and semi-crystalline thermoplastics, such as various polyamides (PA), polycarbonates (PC), polyphthalamides (PPA), polyphenylene oxides (PPO), polybutyls in the selection of various materials. Ene terephthalate (PBT), cycloolefin polymer (COP), liquid crystal polymer (LCP) or also copolymers or blends thereof, for example acrylonitrile-butadiene-styrene/polycarbonate blends (PC/ABS) or PBT /PET. It is marketed in quality suitable for LDS from all well-known polymer manufacturers.

In addition, the polymeric composition comprising the composite pigment used according to the invention as an LDS additive may optionally further comprise fillers and/or colorants and stabilizers, adjuvants and/or flame retardants.

Suitable fillers are, for example, various silicates, SiO ₂ , talc, kaolin, mica, wollastonite, glass fibers, glass beads, carbon fibers and the like.

Suitable colorants are organic dyes and also inorganic or organic color pigments. Since the LDS plastic composition provided with the LDS additive according to the invention is very light and can thus be easily colored, virtually any soluble dye or insoluble colored pigment suitable for plastics can be used. Examples that may be mentioned are the white pigments TiO ₂ , ZnO, BaSO ₄ and CaCO ₃ , which are particularly commonly used here. The amount and type of filler and/or colorant added here is limited only by the individual composition suitable for LDS, in particular the respective specific material properties of the plastics used.

Surprisingly, the composite pigments used according to the invention consisting of at least 80% by weight of TiO ₂ and (Sb,Sn)O ₂ based on the total weight of the complex pigment are very suitable as LDS additives, even they are in the range of 0.1 to 30% by weight. In the polymeric composition for the LDS process, which is added at the usual use concentration, although the composite pigment as described above has a specific electrical conductivity, the polymer-containing coating or the polymeric base body is applied to the base body of the article to be manufactured. It has been found that it does not yield the formation of an electrically conductive path. In addition, it has an inherent hue of pale white-grey to bluish gray that does not impart an obstructive dark intrinsic hue on the plastic to which they are added. The L ^* values (luminescence values) measured in the CIELab* system of plastics containing additives according to the invention in only 2% by weight concentration based on plastics are greater than 65 as measured using Minolta CR-300. LDS-compatible plastics comprising the LDS additive according to the present invention can thus be colored with any colorant without a large amount of colorant reducing or nullifying the efficacy of the LDS additive if necessary. However, at the same time, the LDS additive used according to the invention has high laser activity and when applied to a laser in the LDS process yields a desired microrough surface in the conductive structure that is removed and carbonized by the laser beam, resulting in a good quality subsequent metal. Enables anger. Under the best conditions, good metallization is as very good metallization as possible, particularly surprisingly, only by the wide bandwidth of the various laser settings. The conditions for laser action that are most suitable for the actual existing environment can thus be selected for the LDS process in each case, and there is no expected reduction in quality in the case of subsequent metallization. When the LDS additive used is a particularly preferred embodiment of the invention, i.e. a composite pigment having a coating consisting of or at least predominantly comprising a TiO ₂ core and an antimony-doped tin dioxide disposed on the surface of the core, a composite pigment The decomposition of the organic polymeric material surrounding a does not occur upon use as an LDS additive in a plastic-containing polymeric composition.

However, it is particularly surprising that, as already mentioned above, the LDS-compatible composition comprising the LDS additive used according to the invention and otherwise not containing additional electrically conductive components is in the high frequency range (HF range, 1-20 GHz). It is a fact that it satisfies the conditions for use. To achieve this, the plastic composition should have a relatively low relative permittivity ε _'r (a ratio of the dielectric constant of the medium compared to the vacuum) and low dielectric loss factor tan δ (the medium is measured in the energy loss caused by the electric field). Both parameters are frequency- and also temperature-dependent and therefore must be measured under the conditions of use in which the electronic components are manufactured by the normally operated LDS process. For high frequency applications, suitable measurement conditions are accordingly at frequencies above 1 GHz and at room temperature. The dielectric loss factor of an LDS-compatible composition provided with an LDS additive, measured at frequencies above 1 GHz, should be 0.01 or less if such polymeric composition is suitable for HF applications. The polymeric composition, in particular the thermoplastic composition, comprising the LDS additive used according to the invention in the above-mentioned amount and not having an additional electrically conductive component satisfies the above conditions.

The invention also relates to a polymeric composition comprising at least one organic polymeric plastic and an LDS additive, wherein the LDS additive is at least 80% by weight of titanium dioxide (TiO ₂ ) and antimony-doped tin, based on the total weight of the composite pigment. It is a complex pigment composed of dioxide ((Sb,Sn)O ₂ ). The polymeric composition here comprises an LDS additive in a proportion of 0.1 to 30% by weight, based on the total weight of the polymeric composition.

Details of the material composition of the LDS additives, the polymeric materials used and any auxiliaries and additives present, such as fillers, colorants, etc., have already been described above. Reference to this is made here.

The polymeric composition according to the invention is intended for use in an LDS process (laser direct structuring process) for the production of a metallized circuit structure on a three-dimensional plastic base body or a three-dimensional base body with a plastic-containing coating. It has a pale intrinsic coloration that can be colored as needed using conventional dyes and/or colored pigments without the use of colorants, and is very suitable for use in high frequency applications, through the addition of the LDS additive according to the invention. It affects the good degree of metallization of the conductive structure produced by the laser beam, where the laser parameters can be selected in a wide spectrum.

The invention also relates to an article having a circuit structure manufactured by the LDS process, wherein the article is a basic body or a polymeric basic body of an article having a polymer-containing coating and a metallic conductor track disposed on the surface of the basic body. Wherein the polymeric base body or polymer-containing coating of the base body comprises at least 80% by weight of titanium dioxide (TiO ₂ ) and antimony-doped tin dioxide ((Sb,Sn)O _It contains an LDS additive composed of a composite pigment composed of ₂ ). Such articles, in particular articles comprising organic plastics, are used, for example, in telecommunications, medical technology or automobile construction, where they are used as electronic components, for example mobile phones, hearing aids, dental devices, automatic electronics, and the like.

1 shows a SEM photograph of the LDS additive according to the present invention according to Example 1.

The present invention will be described below with reference to examples, but is not limited thereto.

Example 1:

Preparation of composite pigments:

Realistic spherical TiO ₂ particles (Kronos 2900, KRONOS Inc.) with an average particle size in the range of 100-300 nm (measured by the laser diffraction method using a measuring device from Malvern Ltd., UK, Malvern 2000 under standard conditions). Co., Ltd.) 100 g is heated to 75°C while stirring in 2 l of demineralized water. The pH of the suspension is adjusted to a value of 2.0 using 10% hydrochloric acid. A solution of tin antimony chloride in hydrochloric acid consisting of 264.5 g of 50% SnCl ₄ solution, 60.4 g of 35% SbCl ₃ solution and 440 g of 10% hydrochloric acid is then slowly weighed, where the pH of the suspension is 32% sodium hydroxide solution Is added slowly at the same time to keep it constant. When the addition is complete, the mixture is stirred for an additional 15 minutes. The pH is then adjusted to a value of 3.0 by addition of 32% sodium hydroxide solution and the mixture is stirred for an additional 30 minutes.

The product is filtered, washed, dried, calcined for 30 minutes at a temperature of 500-900° C. and sieved through a 50 μm sieve.

A composite pigment comprising TiO ₂ and (Sb,Sn)O ₂ having a particle size in the range of 0.1 to 1.7 μm with a D ₅₀ value of 0.18 μm and a D ₉₀ value of 0.74 μm is obtained. The composite pigment has a pale green-gray mass tone. The Sn:Sb ratio in the coating is 85:15.

Example 1:

Minolta Co., Ltd. Measurement of the luminescence value corresponding to L* in the CIELab* system, measured using the Minolta CR-300 measuring device from:

5% by weight of the LDS additive is incorporated into PC/ABS (Xantar C CM 406, Mitsubishi Engineering Plastics) by means of a co-rotating twin screw extruder. The extrudate is a pelletized strand and then dried at 100°C. A test plate with dimensions of 60 x 90 x 1.5 mm is then injection-molded in an injection-molding machine.

In the CIELab system, the luminescence value L* is measured using a Minolta CR-300 measuring device under standard conditions. The average value of five different measurements is shown in each case.

The following values are determined:

Table 1:

(Minatec® 51 and Iriotec® 8825 are products from Merck KGaA; with respect to the comparative example, the particle size in Table 1 is rounded up in each case, and only 2.5% by weight of the additive is used in Example 2 according to the invention)

From Table 1 it can be seen that the composite pigments used according to the invention have significantly higher luminescence values in the polymeric plastic matrix than granules composed of antimony-doped tin dioxide. The luminescence values compared to mica coated with antimony-doped tin dioxide are slightly better in the examples according to the invention than in the comparative examples at half and the same concentration of the LDS additive.

Example 2:

Identification of metallization properties:

Similar to Use Example 1, 5% by weight of an LDS additive (Cu spinel, a material according to Comparative Example 4 and a material according to Example 1 of the present invention) was incorporated in PC/ABS by an extruder in each case, and a test plate Is prepared from a compound produced in an injection-molding machine. The test plate is 1064 nm with different laser intensities and frequencies ranging from 3-16 W and 60-100 kHw to the test field in the grid in such a way that some material ablation is done with the simultaneous carbonization of the treated area. It is processed by fiber laser. Metallization with copper is then carried out in a commercially available reducing copper bath (MID Copper 100 B1, MacDermid). The metallization properties are approached with reference to the structure of the copper layer on the substrate. The plating index (according to MacDermid) is shown, which is obtained from the quotient of the built-up copper layer of the test material and the built-up copper layer of the reference material. The reference material used is a PBT test plate with a proportion of 5% by weight of copper spinel.

The experiment showed that the LDS additive used according to the invention was significantly better than the mica flakes according to Comparative Example 4 coated with antimony-doped tin dioxide, both for metallization in a range of laser parameters, and for the nominal value of the plating index. Values, comparable to Cu spinels at peak values, and show very good metallization values, especially at relatively high laser powers.

Example 3:

Measurement of substances for HF compatibility:

A test plate such as that from Use Example 2 was measured with the difference in which laser treatment and metallization were not made prior to measurement.

The dielectric constant of a material is measured over a range of frequencies and using a variety of methods. Measurements are carried out at room temperature. For measurements at frequencies in the 1 MHz to 1 GHz range, the Agilent E4991A impedance analyzer is used with the Agilent 16453 test holder. Evaluation is performed using the E4991A's "Mate-rial Measurement Firmware".

For measurements at 2.69 GHz and 3.9 GHz, a high-quality resonator (a cavity resonator in TE111 mode) is used, and the resonance characteristics of the empty resonator and the resonator containing dielectric samples are measured using a Rhode & Schwarz ZVA network analyzer. Assessments were made by S. Zinal and G. Boeck, "Complex Permittivity Measure-ments using TE11p Modes in Circular Cylindrical Cavities," IEEE Trans. Microwave Theory Tech., Vol. 53, pp.1870-1874, June 2005.

The following measurements are obtained for a frequency of 1 GHz:

ε'_r tanδ

Example 1: 3.04 0.00373

Cu spinel: 2.91 0.00411

Compound Example 4: 2.98 0.00488

The following measurements are obtained for a frequency of 2.69 GHz:

ε'_r tanδ

Example 1: 2.861 0.0048

Cu spinel: 2.759 0.00496

Compound Example 4: 4.029 0.0216

The following measurements are obtained for a frequency of 3.9 GHz:

ε'_r tanδ

Example 1: 2.892 0.005

Cu spinel: 2.736 0.0047

Compound Example 4: 4.072 0.0253

As the measurements indicate, copper spinel is generally used as an LDS additive and the LDS additive according to Example 1 used according to the present invention is comparable for suitability in the high frequency range, while mica flakes coated with antimony-doped tin dioxide (Comparative Example 4) has both an excessively high relative permittivity and a considerably excessively high dielectric loss factor at frequencies above 1 GHz.

Claims (16)

A composite pigment comprising titanium dioxide (TiO ₂ ) and antimony-doped tin dioxide ((Sb,Sn)O ₂ ), used as an LDS additive (laser direct structuring additive) in a polymeric composition,
The sum of titanium dioxide (TiO ₂ ) and antimony-doped tin dioxide ((Sb,Sn)O ₂ ) is at least 80% by weight based on the total weight of the composite pigment,
The complex pigment has at least one core and a coating arranged on the core, and
-The core is made of TiO ₂ and has a coating containing (Sb,Sn)O ₂ , or
or
-A composite pigment, characterized in that the core consists of (Sb,Sn)O ₂ and has a coating comprising TiO ₂ . The composite pigment according to claim 1, wherein the core has an isotropic shape. The composite pigment according to claim 1 or 2, characterized in that the core is in the form of a sphere, a rectangular parallelepiped, a regular polygon or a semi-regular polygon having n faces, wherein n is in the range of 4 to 92, or in the form of granules. The composite pigment according to claim 1 or 2, wherein the proportion of the coating is 20 to 70% by weight based on the total weight of the composite pigment. The composite pigment according to claim 1 or 2, characterized in that the core has a particle size in the range of 0.001 to 10 μm. The composite pigment according to claim 1 or 2, characterized in that the coating has a layer thickness in the range of 1 to 500 nm. The composite according to claim 1 or 2, wherein the composite pigment comprises one or two or more primary particles each, and each primary particle has a core and a coating arranged on the core. Pigment. The composite pigment according to claim 1 or 2, wherein the composite pigments each have a particle size in the range of 0.1 to 20 μm. The composite pigment according to claim 1 or 2, wherein the composite pigment is present in the polymeric composition in a proportion ranging from 0.1 to 30% by weight, based on the total weight of the polymeric composition. The composite pigment according to claim 1 or 2, characterized in that the polymeric composition comprises, in addition to the LDS additive, at least one organic polymeric plastic and optionally fillers and/or colorants. A polymeric composition comprising at least one organic polymeric plastic and LDS additive, wherein the LDS additive is a composite pigment comprising titanium dioxide (TiO ₂ ) and antimony-doped tin dioxide ((Sb,Sn)O ₂ ),
The sum of titanium dioxide (TiO ₂ ) and antimony-doped tin dioxide ((Sb,Sn)O ₂ ) is at least 80% by weight based on the total weight of the composite pigment,
The complex pigment has at least one core and a coating arranged on the core, and
-The core is made of TiO ₂ and has a coating containing (Sb,Sn)O ₂ , or
or
-A polymeric composition, characterized in that the core consists of (Sb,Sn)O ₂ and has a coating comprising TiO ₂ . 12. The polymeric composition of claim 11, wherein the LDS additive is present in the polymeric composition in a proportion of 0.1 to 30% by weight based on the total weight of the polymeric composition. An article having a circuit structure manufactured by the LDS process consisting of a plastic base body or a base body with a plastic-containing coating and a metallic conductor track disposed on the surface of the base body, the plastic base body or a plastic-containing coating on the base body An article containing an LDS additive in which water is composed of a complex pigment comprising titanium dioxide (TiO ₂ ) and antimony-doped tin dioxide ((Sb,Sn)O ₂ ),
The sum of titanium dioxide (TiO ₂ ) and antimony-doped tin dioxide ((Sb,Sn)O ₂ ) is at least 80% by weight based on the total weight of the composite pigment,
The complex pigment has at least one core and a coating arranged on the core, and
-The core is made of TiO ₂ and has a coating containing (Sb,Sn)O ₂ , or
or
Article characterized in that the core consists of (Sb,Sn)O ₂ and has a coating comprising TiO ₂ . delete delete delete

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