Use of colored effect pigments for enhancing the infrared absorption capacity of colored polymers

Abstract

The present invention relates to the use of colored effect pigments for enhancing the infrared absorption capacity of colored polymers and to a method for enhancing the infrared absorption capacity of colored polymers.

Description

TECHNICAL FIELD

[0001] The present invention relates to the use of colored effect pigments for enhancing the infrared absorption capacity of colored polymers and to a method for enhancing the infrared absorption capacity of colored polymers. BACKGROUND

[0002] When used in plastic applications, pearlescent pigments open up new dimensions in color design. Typically, pearlescent pigments are based on platelet-shaped substrate particles which are covered with one or more interference layers of materials which exhibit different refractive indices from each other. In most cases, these interference layers use metal oxides. By multiple reflection of light, unique luster and color effects emerge from such layer sequences in effect pigments and they impart interesting optical properties to plastic parts dyed therewith. Due to their chemical structure, most decorative effect pigments exhibit infrared reflection properties.

[0003] However, for some polymer applications in the plastics industry, it is desirable that the colored polymers have infrared absorption properties. Heating by means of infrared radiation is widely used in industry, in particular for heating or drying polymer materials. Some examples are injection blow molding processes, injection stretch blow molding processes, thermoforming processes, rapid prototyping, curing processes or welding processes of polymer materials.

[0004] Heating or reheating of polymer materials by infrared radiation has specific advantages over other forms of heating such as convection ovens, because the emitted radiation is only absorbed by the polymer part to be processed and not by the surrounding air or objects. Energy efficiency is thereby ensured and the costs of the respective equipment are limited. Thus, infrared heating is an important component in many polymer processing methods. The unique properties of infrared heat, such as directional heat, fast heating, fast cooling and precise temperature control, lead to efficient polymer processing in the plastics industry.

[0005] In order to make polymer materials have infrared absorption properties, several proposals have been made in the past.

[0006] In EP 1 756 221 B1, it is proposed to use inorganic materials to improve the reheating properties of polymer materials, wherein the inorganic materials are selected from titanium nitride, indium tin oxide, reduced indium tin oxide and antimony tin oxide. The respective polymer material comprises at least 1 ppm and at most 500 ppm of such infrared absorbing material. The inorganic materials are composed of particles having a maximum dimension of less than 10 pm.

[0007] If the polymer material is to be dyed, either blue titanium nitride is used or for this purpose additional gray or black pigments, such as carbon black, iron oxides, copper chromite or metallic antimony, are added.

[0008] To obtain colors other than blue, black, or gray, near-infrared dyes need to be added.

[0009] US 8,932,512 B2 describes polymers with high infrared absorption capabilities. Here, the colorless polymer compound contains light-colored or transparent spherical, flake-shaped, or needle-shaped particulate semiconductor material or a particulate substrate coated with a light-colored or transparent semiconductor material. The particulate substrate may be particularly selected from mica flakes, glass flakes, SiO2 beads, TiO2 beads, TiO2 needles, etc., while the semiconductor material is, for example, indium oxide, antimony oxide, tin oxide, or zinc oxide.

[0010] Since the purpose of this invention is to enable transparent or colorless polymer compounds to have increased infrared absorption capabilities, the corresponding IR-absorbing additives are light-colored or transparent and colorless in order not to interfere with the color characteristics of the resulting plastic parts.

[0011] In the literature cited above, the infrared absorbing additives exhibit only very limited color properties or are essentially transparent and / or colorless. Therefore, there is still a need for particulate additives that enable polymer-based plastic parts to possess attractive effect colors and high gloss and / or shimmer, while simultaneously exhibiting good infrared absorption properties, without overloading them, which could hinder their application characteristics. Summary of the Invention

[0012] Therefore, the object of the present invention is to find a particulate additive that enables a polymer composition to have an attractive color and gloss and / or shimmering effect, while simultaneously providing the polymer composition with sufficient infrared absorption capacity without the need for additional infrared absorbing additives or additional dyeing additives.

[0013] Furthermore, the object of this invention is to find a method for enhancing the infrared absorption capability of colored polymers by adding additives that can provide color and infrared absorption properties to polymer compositions.

[0014] The objective of this invention is to enhance the infrared absorption capability of colored polymers by using colored effect pigments, wherein the colored effect pigments comprise at least one layer composed of carbon.

[0015] Furthermore, the object of the present invention is achieved by a method for enhancing the infrared absorption capability of a colored polymer, wherein a polymer composition is mixed with a colored effect pigment comprising at least one layer of carbon, the amount of the colored effect pigment being 0.1 to 10% by weight based on the total weight of the effect pigment and the polymer composition, thereby giving the polymer composition color and enhanced infrared absorption properties.

[0016] In the context of this invention, infrared radiation refers to radiation within the solar spectrum in the wavelength range of 750 to 3000 nm. This infrared wavelength range is further divided into near-infrared (750 nm to 1400 nm) and short-wave infrared (1400 nm to 3000 nm).

[0017] In the sense of this invention, "colored" means any color that can be provided by interference pigments, including not only the usual "colored" colors but also black, white, and gray tones, as well as metallic tones such as silver, gold, bronze, and copper.

[0018] As previously described, flake-effect pigments are known in the art to be used to impart gloss and / or shimmer effects, as well as significant interference colors, to polymer compositions. However, most flake-effect pigments known in the art exhibit infrared reflectivity due to their layered composition, just as they do in the visible spectrum.

[0019] In addition, it is known in the art that carbon black particles absorb infrared radiation to some extent. They can also be incorporated into polymer materials, but their effective infrared absorption may not be achieved without significantly darkening the polymer composition.

[0020] Therefore, the challenge faced by the inventors of this invention is to provide an additive that simultaneously exhibits the color characteristics of interference pigments and the infrared absorption properties of carbon black, without exhibiting the disadvantages that may occur if these two additives are used in combination in a polymer composition.

[0021] Surprisingly, the inventors of this invention have indeed discovered that if conventional colored effect pigments contain at least one layer composed of carbon, they can be modified to exhibit desired optical and infrared absorption properties without exhibiting the disadvantages of a mixture of carbon black particles and colored effect pigments in similar application media.

[0022] To find a suitable balance between interference color and infrared absorption properties, the at least one carbon black layer of the colored effect pigment must be designed in a conformal and uniform manner to provide the desired infrared absorption characteristics without diminishing the color properties of the effect pigment exhibiting interference colors.

[0023] For this purpose, the following colored effect pigments have been found to be useful, which are based on flake-shaped substrate particles coated with at least one interference layer and at least one layer composed of carbon.

[0024] To find a proper balance between infrared absorption and the darkening of color properties of one or more interference layers, it has been shown that it is best to place a carbon-based layer on top of the sheet-like substrate particles coated with at least one interference layer, thus forming the outermost layer of the colored effect pigment (“outermost” in a sense means: the outermost layer that determines the color properties of the respective pigment). In the outermost carbon-based layer, the carbon content is 100% by weight based on the weight of the carbon-based layer. The carbon is present in this layer as a mixture of nanocrystalline carbon and amorphous carbon in a ratio of 5:95 to 95:5, particularly 20:80 to 80:20. The respective contents of amorphous carbon and nanocrystalline carbon depend on the source of the carbon and the reaction temperature in the respective carbon coating process. Preferably, the content of nanocrystalline carbon is higher than the content of amorphous carbon in the carbon-based layer.

[0025] The carbon-based layer forms a pinhole-free, continuous, shape-preserving, and uniform layer, preferably serving as the outermost layer (i.e., the outermost layer that determines the color characteristics) of the effect pigment used in this invention.

[0026] The geometric thickness of the carbon-based layer is in the range of 1 to 10 nm, preferably in the range of 1 to 6 nm, but in an advantageous embodiment it can be as low as 1 to 2 nm. Surprisingly, such an ultrathin carbon-based layer can provide the desired infrared absorption properties to the polymer composition containing the effect pigment, even though the concentration of the effect pigment in the polymer composition is low, as will be described below.

[0027] A geometric layer thickness of less than 1 nm is insufficient to give the effect pigment the desired infrared absorption capability in the polymer, while a layer thickness greater than 10 nm will darken the effect pigment, thereby contaminating one or more interference colors, and the infrared absorption capability will be so high that the resulting colored polymer composition is almost unmanageable during the required heating process with infrared radiation due to the very high operating temperature and the resulting excessively long cooling process.

[0028] The geometric thickness of the carbon-based layer can be determined in a common manner by examining cross-sectional images.

[0029] The carbon content in the effect pigment is in the range of 1 to 10% by weight based on the total weight of the effect pigment.

[0030] Suitable flake-shaped substrate particles for the effect pigments used in this invention are synthetic mica flakes, natural mica flakes, glass flakes, Al2O3 flakes, SiO2 flakes, or Fe2O3 flakes coated with one or more interference layers. The number of interference layers can be 2, 3, 4, 5, or 7, preferably 1, 2, or 3.

[0031] For the interference layer, low-refractive-index materials and / or high-refractive-index materials are used, such as SiO2, Al2O3, Al(O)OH, B2O3, MgO·SiO2, CaO·SiO2, Al2O3·SiO2, B2O3·SiO2, or MgF2 as colorless materials for the low-refractive-index layer, and TiO2, ZrO2, SnO2, ZnO, Ce2O3, Fe2O3, Fe3O4, FeTiO5, Cr2O3, CoO, Co3O4, VO2, V2O5, or NiO as colored or colorless materials for the high-refractive-index layer. High-refractive-index and low-refractive-index materials can advantageously be used alternately in multilayer stacks on sheet-like substrate particles.

[0032] The interference layers made from these materials exhibit geometric layer thicknesses ranging from 20 to 400 nm, preferably from 30 to 300 nm, and especially from 30 to 200 nm.

[0033] TiO2, as a high-refractive-index material, and SiO2, as a low-refractive-index material, are preferred. In particular, a single layer of TiO2 or a TiO2-SiO2-TiO2 layer sequence is preferred, which is located on the sheet-like substrate particles, just below the outermost layer composed of carbon.

[0034] Basic effect pigments are commercially available from various suppliers. These pigments are typically colored (providing interference and / or absorption colors) and consist of flake-like substrate particles coated with at least one interference layer (without a carbon layer). They exhibit particle sizes ranging from 1 to 400 μm, preferably 5 to 200 μm, and especially 5 in the 100 μm range. The particle size and particle size distribution can be determined by various methods commonly used in the art. However, according to the invention, laser diffraction is preferably used in a standard method using a Malvern Mastersizer 3000, APA300 (a product of Malvern Instruments Ltd., UK). The advantage of this method is that both particle size and particle size distribution can be determined simultaneously under standard conditions.

[0035] These commercially available colored base effect pigments are modified by carbon-based layers as described above for use as infrared absorption enhancement additives in the sense of this invention.

[0036] To give commercially available colored effect pigments the required carbon-based layer, the base effect pigment should be carbon-coated using a fluidized bed assisted CVD method operated at temperatures ranging from 200 to 900°C, particularly from 500 to 700°C. The carbon source (i.e., the carbon precursor) is selected from carbon-containing organic solvents, particularly those that decompose at temperatures below 500°C, such as ethanol, isopropanol, 2-methyl-3-butyn-2-ol, sugar compounds such as confectionery sugars, glucose, fructose, dextrose, or any other sugars known to those skilled in the art, acetone, and toluene. Acetone and toluene are particularly preferred. The carbon precursor can be in liquid, solid, or gaseous form. Mixtures of two or more solid, liquid, and gaseous carbon precursors are also possible. Mixtures of different organic solvents, mixtures of different sugars, or mixtures of sugars and solvents can also be used as carbon precursors. These solvents can be injected into the reactor as liquids for fine spraying or as gases. However, it is advantageous to use acetone or toluene, each as a single carbon source.

[0037] The carbon source is fed into the reactor in a carrier gas stream, which is an inert gas or a mixture of hydrogen and nitrogen. Argon or nitrogen can be used as the inert gas, but nitrogen is preferred. The carbon source can be used at room temperature or can be used in a preheated form when fed into the reactor. It is fed into a carrier gas stream enriched with a uniformly distributed carbon precursor.

[0038] The reaction time is approximately 5 to 200 minutes, preferably 10 to 150 minutes. During this reaction time, a dense, continuous outer layer composed of carbon is applied to the colored base effect pigment.

[0039] After heat treatment, the resulting colored, carbon-coated effect pigments are cooled and sorted. If necessary, one or more grinding processes may be performed before or after the sorting (for further separation of the obtained pigments).

[0040] The carbon coating method for the colored basic effect pigment can be carried out in a batch method or a continuous method.

[0041] For some application media, it may be advantageous that the colored carbon-coated effect pigments used according to the invention are also ultimately provided for so-called post-coating or post-treatment.

[0042] Such post-coating or post-treatment typically occurs on the surface of effect pigments that already possess all the layers that determine their color properties. It serves to adapt the effect pigments to their application requirements and can consist of organic or inorganic compounds or a mixture of inorganic and organic components.

[0043] In the case of inorganic compounds, dielectric compounds can be used. They are known to impart better dispersibility, light fastness, etc., to various types of effect pigments, and post-coatings made from them are well-known in the art. Their thickness is generally less than 20 nm, and especially between 1 and 15 nm. The dielectric compound forming such a thin post-treatment layer does not interfere with the overall pigment system and therefore does not contribute to the color properties of the resulting pigment. Typically, the dielectric compounds used for this purpose are silica, aluminum dioxide, cerium oxide, and / or tin oxide, either as a single component or in the form of a mixture.

[0044] In addition to or as an alternative to the inorganic dielectric layer used for post-coating as described above, thin coatings of organic materials (e.g., various organosilanes, organotitanates, organozirconates) can also be applied as the outermost coating to the pigment surface of the present invention to improve their applicability in different application media. Such coatings are known in the field of effect pigments, and therefore their applications are within the general skill of those skilled in the art. Examples of so-called “post-treatment” or “post-coating” of organic or inorganic effect pigments that can be used in this invention as described above can be found in the following documents: EP 0 632 109, US 5,759,255, DE 43 17 019, DE 39 29 423, DE 32 35017, EP 0 492 223, EP 0 342 533, EP 0 268 918, EP 0 141 174, EP 0 764 191, WO 98 / 13426, or EP 0 465 805; the contents of which will be incorporated herein by reference.

[0045] The colored effect pigment used in this invention is incorporated into the polymer composition in an amount ranging from 0.1% to 10% by weight, based on the total weight of the polymer composition thus colored (i.e., based on the colored polymer). Preferably, the concentration of this special effect pigment is as low as 0.5% to 2% by weight. Since the special colored effect pigment used according to this invention has a high infrared absorption capacity, the aforementioned low concentration is sufficiently high to give the resulting colored polymer a sufficiently high infrared absorption capacity.

[0046] The polymer that may have the infrared absorption enhancing additive according to the invention is a thermoplastic or thermosetting material. Preferably, a thermoplastic material is used.

[0047] In a first aspect, the polymer is dyed by adding a special colored effect pigment according to the invention, which gives the polymer attractive color and gloss / glitter properties, and further gives them enhanced infrared absorption capabilities.

[0048] Secondly, in addition to coloring the polymer with the special colored effect pigment, the polymer can also be additionally colored by using conventional absorbing pigments, dyes, or even conventional flake-like effect pigments that do not contain a layer of carbon. It goes without saying that if particulate colorants (i.e., dyeing pigments) are used for this purpose, the total amount of the special colored effect pigment and the additional dyeing pigment used according to the invention must not exceed the maximum pigment loading possible in their respective polymer applications. In all cases, the concentration of the special colored effect pigment according to the invention must be sufficiently high to ensure that the relevant polymer composition has enhanced infrared absorption compared to a polymer composition that is otherwise composed of the same components except for the absence of at least one layer of carbon in the colored effect pigment (i.e., using a colored effect pigment corresponding to the base portion of the special colored effect pigment, i.e., simply not containing the carbon layer).

[0049] As an alternative dyeing method, colored pigments or dyes known in the art can be used. For example, organic and inorganic colorants and pigments, and especially any other type of effect pigments, can be used. Organic pigments and colorants are, for example, azo pigments, diazo pigments, polycyclic pigments, cationic, anionic, or nonionic colorants. Inorganic colorants and pigments are, for example, white pigments, colored pigments, black pigments, or effect pigments. Examples of other suitable effect pigments are metallic effect pigments, pearlescent pigments, or interference pigments, which are typically based on single- or multi-coated flakes of aluminum, mica, glass, Al₂O₃, Fe₂O₃, SiO₂, etc. Examples of the structure and properties of these pigments are disclosed in particular in RD 471001 or RD 472005, the disclosure of which is incorporated herein by reference.

[0050] Generally, the colored polymer may also contain other additives commonly used in the art, such as binders, solvents, fillers, stabilizers and / or surfactants, which are thermally stable under the required thermoforming working conditions.

[0051] Polymer materials for colored polymers in the sense of this invention include, for example, the following polymers: polyethylene (PE, HDPE, LDPE), polypropylene (PP), polyamide, polyester, polyester-ester, polyether-ester, polyphenylene ether, polyacetal, polyalkylene terephthalate, polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polyvinyl acetal, polyvinyl chloride (PVC), polyphenylene ether (PPO), polyoxymethylene (POM), polystyrene (PS), acrylonitrile styrene (AS), acrylonitrile-styrene-acrylate (ASA), acrylonitrile-butadiene-styrene (ABS), styrene-butadiene copolymer (SBC), polycarbonate (PC), polyethersulfone, polyurethane (TPU), polyether ether ketone (PEEK), or copolymers or mixtures thereof.

[0052] As polyalkylene terephthalates, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polycyclohexanedimethyl terephthalate (PCT), or polyethylene terephthalate diol (PETG) are preferred. They can also be used in the following forms: post-consumer recycled form (post-consumer recycled polyethylene terephthalate (PCRPET)), post-industrial recycled form (post-industrial recycled polyethylene terephthalate (PIRPET), or as re-milled polyethylene terephthalate.

[0053] Depending on the type of infrared heating process, the type of polymer can be used based on the expertise of those skilled in the art. For example, alkylene terephthalates such as polyethylene terephthalate (PET) are frequently used in the manufacture of beverage bottles, and they can undergo injection stretch blow molding processes.

[0054] Polymer materials containing the special colored effect pigment according to the invention should be heated or reheated by infrared radiation. Specifically, the heating or reheating method means thermoforming, injection stretch blow molding, polymer welding, polymer drying, or methods for polymerizing and / or curing polymer materials. In all these methods, the presence of the special colored effect pigment according to the invention endows the respective polymers with amplified infrared absorption capacity compared to polymers that are otherwise identical in composition except for not containing the special colored effect pigment containing at least one carbon layer as described above. Surprisingly, polymers containing the special colored effect pigment according to the invention also exhibit increased infrared absorption capacity compared to colored polymer compositions that exhibit the same color due to a mixture of flake-like effect pigments (without a carbon layer) and a suitable amount of carbon black particles.

[0055] The special colored effect pigment used according to the invention is incorporated into the respective polymer composition by any method known and used in the art. For example, the special effect pigment can be mixed with particles of the respective polymer composition and extruded or injection molded together with the polymer particles to obtain an intermediate product, which is then processed in a suitable manner at a later stage. The intermediate product formed in this way exhibits a very uniform distribution of the special colored effect pigment, allowing subsequent thermoforming preparation steps to be carried out under favorable conditions.

[0056] Additional but different coloring pigments or dyes and optional additives, such as binders, solvents, fillers, stabilizers and / or surfactants, may be added before, during or after the addition of the special colored effect pigment to the polymer composition particles, which are thermally stable under the required operating conditions of the subsequent thermoforming process.

[0057] The present invention also relates to a method for enhancing the infrared absorption capability of colored polymers, characterized in that a polymer composition is mixed with a colored effect pigment comprising at least one layer of carbon, wherein the colored effect pigment is included in the polymer composition in an amount of 0.1 to 10% by weight based on the total weight of the colored effect pigment and the polymer composition, thereby giving the polymer composition color and enhanced infrared absorption capability.

[0058] Details regarding polymer compositions that can be used with the colored polymers of the present invention have been discussed to some extent above. The composition of special colored effect pigments comprising at least one layer of carbon and their concentrations in the colored polymers have also been discussed. All details in this regard also apply to methods for enhancing the infrared absorption capabilities of colored polymers.

[0059] Special colored effect pigments comprising at least one layer of carbon impart attractive color (interference and / or absorption color) and gloss, shimmer, or even metallic effects to the polymer composition, while simultaneously ensuring high infrared absorption capacity of the resulting colored polymer. This high infrared absorption capacity may result in a reduced content of infrared absorbing additives in the polymer (in this case, a reduced content of the special effect pigment compared to ordinary infrared absorbing additives) or a lower energy supply required for heat treatment under infrared radiation.

[0060] Furthermore, the use of the special colored effect pigments according to the invention does indeed improve the UV resistance of colored polymer compositions compared to those in which carbon black particles are added to a polymer matrix dyed with common effect pigments that do not have a carbon layer thereon.

[0061] Since the special colored effect pigment is contained in the colored polymer according to the invention, the latter is able to absorb infrared radiation in the wavelength range of 750 to 3000 nm of the solar spectrum, in an amount such that in ordinary thermoforming or similar methods under the influence of infrared radiation, no additional infrared absorbing additives are required to enable the resulting polymer composition to be heated or reheated.

[0062] Therefore, the present invention also relates to a method for thermoforming, injection blow molding, injection stretch blow molding, welding, drying, or curing a colored plastic part, the method comprising irradiating the plastic part with infrared radiation in the wavelength range of 750 to 3000 nm of the solar spectrum, wherein the plastic part is composed of a colored thermoplastic or thermosetting polymer composition comprising a colored effect pigment comprising at least one layer of carbon, wherein the colored effect pigment is present in the polymer composition in an amount of 0.1 to 10% by weight based on the total weight of the effect pigment and the polymer composition, and thereby the thermal conductivity of the colored plastic part is improved compared to a plastic part that is otherwise identical except for not containing the colored effect pigment having the at least one carbon layer.

[0063] The colored plastic parts in this invention are either products made from a colored polymer composition that ultimately needs to be cured, dried, and / or polymerized, or intermediate products that should be thermoformed or stretch blow molded in the process. Thermoforming and stretch blow molding are preferred. Attached Figure Description

[0064] Figure 1a This shows the distribution of carbon black in a polymer matrix containing common colored effect pigments and carbon black particles.

[0065] Figure 1 b The diagram shows the distribution of carbon black in a polymer matrix containing the colored effect pigment according to the invention.

[0066] Figure 2a The figure shows the temperature difference between the inner and outer surfaces of the preform in an ISBM process using 800 bottles per hour, 100% IR lamp energy, and the composition of Comparative Example 2.

[0067] Figure 2b The figure shows the temperature difference between the inner and outer surfaces of the preform during an ISBM process using 800 bottles per hour, 96% IR lamp energy, and the composition of Example 2.

[0068] Figure 3 The table shows a comparison of the color changes of the plates prepared according to Examples 3, 4 and 5 and Comparative Examples 3, 4 and 5 after 1000 hours of artificial weathering.

[0069] Figure 4 : Shows uncoated colored effect pigments (1)( The IR absorption capacity of 6103Icy White, and the carbon-coated effect pigment (3) used according to the present invention (coated with about 1% by weight of carbon) The IR absorption capacity of 6301Icy White) and the blend of uncoated colored effect pigments and carbon (2) (blended with approximately 0.01% carbon based on 100% by weight of the blend). IR absorption capacity of 6301Icy White. Detailed Implementation

[0070] The invention is described in more detail in the following embodiments, but the invention should not be limited to these embodiments.

[0071] Example 1 and Comparative Example 1 :

[0072] Thermoforming

[0073] A wide variety of plastic articles are prepared by thermoforming methods. Typically, a thermoforming system includes a source of thermoplastic sheet material, such as a winding table, a heating table for heating the thermoplastic sheet material, and a thermoforming press table, wherein the heated thermoplastic sheet material is shaped by a vacuum pressure system using upper and lower pressure plates, thereby thermoforming the molded article in the sheet material. The heating station for heating the thermoplastic sheet material is used to heat the top and / or bottom of the sheet material to a preselected temperature, typically ranging from 80°C to 150°C. The preheating station can, for example, employ a typical IR heater (e.g., a quartz heater).

[0074] To compare the thermoforming characteristics of the colored plastic parts according to the present invention (Example 1) and the colored plastic parts according to the prior art (Comparative Example 1), ABS (derived from BASF SE) colored as follows was used. GP22) Prepares a thin film with a thickness of 600 μm:

[0075] Example 1 : 1% by weight of the colored effect pigment used according to the present invention (obtained from MerckKGaA of Darmstadt). 111Rutil Fine Satin, which is coated with 6% by weight of carbon based on the weight of the resulting pigment. The pigment and the film made therefrom exhibit a metallic gray color.

[0076] Comparative Example 1 : 1% by weight 111Rutil Fine Satin and 0.05% Carbon Black ( P60). A carbon black concentration of 0.05% was selected to match the color of Example 1. The resulting film exhibited a metallic gray color.

[0077] The films have a similar color. These films were formed into parts using a thermoforming machine (model 450DT) from Formech at 70% of the maximum emitter power. The heating time required to obtain optimal results was measured in each case and is comparable between the individual films (see Table 1). Thermoforming tests were performed using film sheets measuring 10 cm × 15 cm and irradiated with a quartz emitter.

[0078] Table 1:

[0079]

[0080] As the measurements show, the concentration of 1% by weight of the colored effect pigment used in this invention already has a small, measurable effect in this plastic system. The final carbon concentration in the polymer corresponds to 0.06% C; however, a significant reduction in heating time of 10 seconds, or approximately 30%, can be achieved.

[0081] Furthermore, the temperature of the film was measured after a 20-second heating time. The results in Table 2 show that the temperature of the plastic part according to Example 1 was higher than that of Comparative Example 1.

[0082] Table 2:

[0083]

[0084] Because the polymer and the pearlescent pigment have different IR absorption properties, heating the polymer matrix containing the pearlescent pigment with IR may result in uneven distribution. The carbon black particles are unevenly distributed within the polymer matrix, and correspondingly enhance IR absorption in an uneven manner. Conversely, the uniform C layer deposited on top of the pearlescent pigment improves the thermal conductivity of the polymer formulation colored with the specific pearlescent pigment according to the invention.

[0085] The differences in the distribution of carbon black in the polymer matrix according to the invention and in the polymer matrix containing common colored effect pigments and carbon black particles according to the prior art (Example 1 and Comparative Example 1) are shown in Figure 1a In (Comparative Example 1) and 1b (Example 1).

[0086] Example 2 and Comparative Example 2:

[0087] Injection stretch blow molding (ISBM)

[0088] As known to those skilled in the art, the ISBM method begins in a first step in which a thermoplastic material (typically a thermoplastic resin) is melted and then injected into a preforming mold to form a preform. When the preform is then demolded from the preforming mold, it can be processed immediately, but more typically, it is cooled and stored and processed at a stretch blow molding station at a subsequent time and / or location. In a second step, the preform is introduced into a stretch blow molding apparatus, where it is blow-molded into its final shape via heating (e.g., IR-heating) and stretching (typically using a mandrel). Unlike other blow molding methods, in the ISBM method, the preform is reheated to a warm temperature sufficient to allow it to inflate, resulting in a biaxial molecular arrangement in the sidewalls of the resulting blow-molded container. With the preform held at the neck, it is stretched axially using air pressure and typically using a stretch bar, and optionally also radially. In the case of bottles, the neck portion of the article may contain threads or flanges suitable for closure, and these typically remain unchanged relative to the preform, as the neck portion is usually not stretched. Articles obtained by injection stretch blow molding can be significantly longer than the preform.

[0089] Bottles produced by injection stretch blow molding (ISBM) are made by injection molding a tubular preform, followed by reheating and simultaneously stretching and blow molding the IR-heated preform into a container. The polymer compositions colored according to the invention can be used in all areas where thermoplastic materials are reheated.

[0090] To manufacture preforms for use in ISBM, a pearlescent pigment (prior art, Comparative Example 2) or a modified pearlescent pigment (according to the present invention, Example 2) containing 20% ​​by weight of masterbatch was prepared. The carbon black content in the comparative example was selected to match the color of the polymer composition according to Example 2.

[0091] The resin product brand of Indorama Ventures, as used in Example 2 and Comparative Example 2. PET 1101 is a commercial-grade copolymer packaging resin. It is commonly used in carbonated soft drink bottles, packaging, and other injection / stretch blow molding applications. Before use, the granules should be dried under vacuum at approximately 85°C for about 8 hours to remove residual moisture.

[0092] A polymer composition having the components disclosed below is injection molded into a preform and further stretched and blow-molded into a 450ml, 33g bottle.

[0093] Preforms are manufactured using a 150-ton injection molding machine, which can produce two preforms per injection. Each cylindrical preform, weighing approximately 33g and about 120mm long, has a threaded top base.

[0094] Polyester injection molding was performed at approximately 270°C. The preform was blow-blown into a 450ml bottle. The maximum linear stretch ratio was 2:1. The circumferential stretch ratio was 2.5:1 (plane) to 4.5:1 (side).

[0095] The preforms of Example 2 and Comparative Example 2 were designed to exhibit similar colors. The final pigment concentrations in the formulation are as follows:

[0096] Example 2:

[0097] For every 100% by weight of the colored polymer composition, according to the present invention, 1% by weight of the colored effect pigment (based on...) 6103Icy White, which has 1% by weight of C deposited on the pigment (i.e., 0.01% by weight of C in the final polymer formulation). The pigment and the preforms made therefrom exhibit a metallic gray color.

[0098] Comparative Example 2:

[0099] For every 100% by weight of the colored polymer composition, 1% by weight 6103Icy White + 0.005% Carbon Black P60). The resulting preform is metallic gray.

[0100] For Comparative Example 2, the settings were set to 800 bottles per hour, with 100% IR lamp energy at the start.

[0101] Figure 2a The results show that when the method is carried out in this manner using the polymer composition according to Comparative Example 2, there is a significant temperature difference between the surfaces inside and outside the preform (“height” is the length of the resulting bottle from the neck to the bottom).

[0102] For Example 2, it was immediately clear in the preliminary tests that a significant difference in the inner and outer surface temperatures of the preform would occur if the preparation conditions as in Comparative Example 2 were used. For this reason, reducing the heater power is both possible and necessary. Therefore, the energy of the IR lamp was reduced to 96%.

[0103] Figure 2b The relationship between the internal and external surface temperatures is shown when using the colored polymer composition of Example 2 for producing 800 bottles per hour with 96% IR lamp energy.

[0104] Subsequently, the preparation rate was increased to 1,000 bottles per hour at 96% IR lamp energy.

[0105] For Example 2, no significant difference in temperature between the internal and external preforms was observed.

[0106] For Comparative Example 2, high-quality bottles were not successfully produced at this high speed and with only 96% of the IR lamp energy. Instead, stretch marks, variable wall thickness, and deformed bottles were observed due to insufficient heating of the preform.

[0107] Examples 3, 4, 5 and Comparative Examples 3, 4 and 5

[0108] UV aging:

[0109] The colored polymer composition system according to the present invention can be used in all fields where thermoplastics have been used to date. For outdoor applications, UV resistance is important and is tested accordingly. Surprisingly, depositing C on a base colored effect pigment improves the UV resistance of the colored polymer composition when compared to colored polymer compositions in which carbon black particles are added to a polymer matrix dyed with a base effect pigment.

[0110] Plastic granules (PMMA from Evonik Industries) Mix 7N with 0.2% Process Aid 24 (a product of ColorMatrix Group, Inc.) in a laboratory tubular ring mixer for 5 minutes. For every 100% by weight of polymer composition, add 1% by weight of pearlescent pigment to the wetted particles and tumble for an additional 5 minutes.

[0111] The granules prepared as described were then processed in an injection molding machine (Kraus-Maffei CX 130280) at 270°C and molded into a 1.5 mm thick plate.

[0112] According to ISO 4892-2 ( The polymer plate was subjected to artificial weathering using Beta+. The optically visible changes were evaluated using grayscale after 1000 hours according to DIN EN 20105-A02.

[0113] The polymer composition includes the following coloring (the polymer compositions of the comparative examples are selected to match the colors of the polymer compositions of the respective embodiments in each case):

[0114] Example 3:

[0115] According to the present invention, for every 100% by weight of the colored polymer composition, there is 1% by weight of a colored effect pigment (coated with 1.5% by weight of carbon-based pigment). 111Rutile Fine Satin is a colored effect pigment. The pigment and plates made therefrom exhibit a metallic gray color.

[0116] Comparative Example 3:

[0117] 1% by weight of the colored polymer composition per 100% by weight 111 Rutile Fine Satin + 0.01% by weight of carbon black ( P60). The resulting plate has a metallic gray color.

[0118] Example 4:

[0119] According to the present invention, for every 100% by weight of the colored polymer composition, there is 1% by weight of a colored effect pigment (coated with 1.6% by weight of carbon-based pigment). 7205 Ultra Rutile Platinum Gold is a colored effect pigment. The pigment and plates made from it exhibit a deep gold color.

[0120] Comparative Example 4:

[0121] 1% by weight of the colored polymer composition per 100% by weight 7205 Ultra Rutile Platinum Gold + 0.015% Carbon Black P60). The resulting board has a deep golden color.

[0122] Example 5:

[0123] According to the present invention, for every 100% by weight of the colored polymer composition, there is 1% by weight of a colored effect pigment (coated with 2% by weight of carbon-based pigment). The NXT T250-23 Galaxy Blue uses a colored effect pigment. The pigment and the plates made from it exhibit a metallic blue color.

[0124] Comparative Example 5:

[0125] 1% by weight NXT T250-23 Galaxy Blue+ 0.01% Carbon Black ( P60). The resulting plate has a metallic blue color.

[0126] Table 3 confirms the visual evaluation of the polymer board at 90° and 45° viewing angles (based on the color change of grayscale).

[0127] Table 3:

[0128] Formulation Comparative Example 3 Example 3 Comparative Example 4 Example 4 Comparative Example 5 Example 5 Visual evaluation at 90° +4 +1 +5 +2 +5 +1 Visual evaluation at 45° +2 +1 +5 +1 +5 +1

[0129] Comparison of plates after 1000 hours of artificial weathering showed significantly less color change when using the pigments according to the invention (Examples 3, 4 and 5). Figure 3 The results of their respective visualizations are displayed.

[0130] Grayscale is used to assess color change and staining during color fastness testing (in this case, artificial aging). It is used for visual evaluation on a scale of 1 to 5, where 5 means "poor" and 1 means "good". The light source / observer condition is D65, with visual evaluation angles of 90° and 45°.

[0131] exist Figure 4 In the image, uncoated colored effect pigments are shown (1)( The IR absorption capacity of 6301Icy White, and the carbon-coated effect pigment (3) used according to the present invention (coated with about 1% by weight of carbon) The IR absorption capacity of 6301Icy White) and the blend of uncoated colored effect pigments and carbon (2) (blended with approximately 1% carbon based on 100% of the blend). IR absorption capacity of 6301Icy White.

[0132] The preparation of the carbon-coated colored effect pigments used in this invention is explained below. All the base colored effect pigments used are commercially available products from MerckKGaA of Darmstadt, Germany.

[0133] A) The carbon-coated material used in Example 1 Preparation of 111Rutil Fine Satin

[0134] 1kg 111Rutil Fine Satin pigment particles were heated to 750°C in a fluidized bed reactor (DI: 100 mm) under a constant inert gas atmosphere (N2). The volumetric flow rate was adjusted to achieve a minimum fluidization rate of 2 mm / s, ensuring excellent mixing and heat / mass transfer performance. Once the reaction temperature of 750°C was reached, toluene, a carbon precursor preheated to 90°C, was added to the fluidized stream. Due to the increased reaction temperature, the carbon precursor decomposed in a manner that initiated the growth of a carbon layer on the particle surface. The CVD process was run for 90 minutes to achieve a carbon layer thickness of 6 nm. After a cooling phase under an inert gas atmosphere (N2), the final pigment was removed from the reactor and sieved.

[0135] B) The carbon-coated material used in Example 2 Preparation of 6103Icy White

[0136] 1kg 6103Icy White pigment particles were heated to 650°C in a fluidized bed reactor (DI: 100 mm) under a constant inert gas atmosphere (N2). The volumetric flow rate was adjusted to achieve a minimum fluidization rate of 2 mm / s, ensuring excellent mixing and heat and mass transfer performance. Once the reaction temperature of 650°C was reached, the carbon precursor acetone was added to the fluidized stream. Due to the increased reaction temperature, the carbon precursor decomposed in a manner that initiated the growth of a carbon layer on the particle surface. The CVD process was run for 90 minutes to achieve a carbon layer thickness of approximately 1 nm. After a cooling phase under an inert gas atmosphere (N2), the final pigment was removed from the reactor and sieved.

[0137] C) The carbon-coated material used in Example 3 Preparation of 111Rutil Fine Satin

[0138] 1kg 111Rutil Fine Satin pigment particles were heated to 600°C in a fluidized bed reactor (DI: 100 mm) under a constant inert gas atmosphere (N2). The volumetric flow rate was adjusted to achieve a minimum fluidization rate of 2 mm / s, ensuring excellent mixing and heat and mass transfer performance. Once the reaction temperature of 600°C was reached, the carbon precursor acetone was added to the fluidized stream. Due to the increased reaction temperature, the carbon precursor decomposed in a manner that initiated the growth of a carbon layer on the particle surface. The CVD process was run for 120 minutes to achieve a carbon layer thickness of approximately 2 nm. After a cooling phase under an inert gas atmosphere (N2), the final pigment was removed from the reactor and sieved.

[0139] D) The carbon-coated material used in Example 4 Preparation of 7205 Ultra Rutile Platinum Gold

[0140] 1kg 7205 Ultra Rutile Platinum Gold pigment particles were heated to 658°C in a fluidized bed reactor (DI: 100 mm) under a constant inert gas atmosphere (N2). The volumetric flow rate was adjusted to achieve a minimum fluidization rate of 2 mm / s, ensuring excellent mixing and heat and mass transfer performance. Once the reaction temperature of 658°C was reached, the carbon precursor acetone was added to the fluidized stream. Due to the increased reaction temperature, the carbon precursor decomposed in a manner that initiated the growth of a carbon layer on the particle surface. The CVD process was run for 120 minutes to achieve a carbon layer thickness of approximately 2 nm. After a cooling phase under an inert gas atmosphere (N2), the final pigment was removed from the reactor and sieved.

[0141] E) The carbon-coated material used in Example 5 Manufacturing of NXT T250-23 Galaxy Blue

[0142] 1kg NXT T250-23 Galaxy Blue pigment particles were heated to 660°C in a fluidized bed reactor (DI: 100 mm) under a constant inert gas atmosphere (N2). The volumetric flow rate was adjusted to achieve a minimum fluidization rate of 2 mm / s, ensuring excellent mixing and heat / mass transfer performance. Once the reaction temperature of 660°C was reached, the carbon precursor acetone was added to the fluidized stream. Due to the increased reaction temperature, the carbon precursor decomposed in a manner that initiated the growth of a carbon layer on the particle surface. The CVD process was run for 75 minutes to achieve a carbon layer thickness of approximately 2 nm. After a cooling phase under an inert gas atmosphere (N2), the final pigment was removed from the reactor and sieved.

Claims

1. Use of a colored effect pigment for enhancing the infrared absorption capability of a colored polymer, wherein the colored effect pigment comprises at least one layer composed of carbon, characterized in that, The colored polymer should be heated or reheated by infrared radiation. Heating or reheating by the action of infrared light is used in thermoforming, injection molding, injection blow molding, injection stretch blow molding, polymer welding, polymer drying, or methods for polymerizing and / or curing polymer materials. The colored effect pigment is present in the colored polymer in an amount ranging from 0.5% to 2% by weight based on the weight of the colored polymer. The carbon layer is the outermost layer of the colored effect pigment and consists of a mixture of nanocrystalline carbon and amorphous carbon in a ratio of 5:95 to 95:

5. The carbon-based layer has a geometric thickness in the range of 1 to 10 nm.

2. The use according to claim 1, characterized in that, The colored polymer absorbs infrared light in the 750 to 3000 nm wavelength range of the solar spectrum.

3. The use according to claim 1 or 2, characterized in that, The colored effect pigment is based on flake-shaped substrate particles coated with at least one interference layer and at least one layer composed of carbon.

4. The use according to claim 1 or 2, characterized in that, The colored effect pigment has a particle size in the range of 1 to 400 μm.

5. The use according to claim 1 or 2, characterized in that, The colored polymer is dyed by the colored effect pigment.

6. The use according to claim 1 or 2, characterized in that, The colored polymer is a colored thermoplastic material or a colored thermosetting material.

7. The use according to claim 1 or 2, characterized in that, The colored polymer is selected from polyethylene (PE), polypropylene (PP), polyamide, polyester, polyester-ester, polyether-ester, polyacetal, polymethyl methacrylate (PMMA), polyvinyl acetal, polyvinyl chloride (PVC), polyphenylene ether (PPO), polystyrene (PS), acrylonitrile styrene (AS), acrylonitrile-styrene-acrylate (ASA), acrylonitrile-butadiene-styrene (ABS), styrene-butadiene copolymer (SBC), polycarbonate (PC), polyethersulfone, polyurethane (TPU), polyether ether ketone (PEEK), or copolymers or mixtures thereof.

8. The use according to claim 1 or 2, characterized in that, The colored polymer is selected from polyalkylene terephthalate, polyethylene naphthalate (PEN), or copolymers or mixtures thereof.

9. The use according to claim 1 or 2, characterized in that, The colored polymer is selected from high-density polyethylene (HDPE), low-density polyethylene (LDPE), or copolymers or mixtures thereof.

10. The use according to claim 1 or 2, characterized in that, The colored polymer is selected from polyoxymethylene (POM).

11. A method for enhancing the infrared absorption capability of colored polymers, characterized in that, The polymer composition is mixed with a colored effect pigment comprising at least one layer of carbon, wherein the amount of the colored effect pigment is 0.5 to 2% by weight based on the total weight of the effect pigment and the polymer composition, thereby giving the polymer composition color and enhanced infrared absorption capability. The carbon layer is the outermost layer of the colored effect pigment and consists of a mixture of nanocrystalline carbon and amorphous carbon in a ratio of 5:95 to 95:

5. The carbon-based layer has a geometric thickness in the range of 1 to 10 nm.

12. The method according to claim 11, characterized in that, The polymer composition absorbs infrared light in the 750 to 3000 nm wavelength range of the solar spectrum.

13. A method for thermoforming, injection blow molding, injection stretch blow molding, welding, drying, or curing a colored plastic part, the method comprising irradiating the plastic part with infrared radiation in the wavelength range of 750 to 3000 nm of the solar spectrum, wherein the plastic part is composed of a colored thermoplastic or thermosetting polymer composition comprising a colored effect pigment, the colored effect pigment comprising at least one layer of carbon, the amount of the colored effect pigment being 0.5 to 2% by weight based on the total weight of the effect pigment and the polymer composition, thereby improving the thermal conductivity of the colored plastic part compared to a colored plastic part otherwise identical except for lacking the colored effect pigment having said at least one carbon layer. The carbon layer is the outermost layer of the colored effect pigment and consists of a mixture of nanocrystalline carbon and amorphous carbon in a ratio of 5:95 to 95:

5. The carbon-based layer has a geometric thickness in the range of 1 to 10 nm.

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