BR112020007009B1 - BLOW MOLDED ARTICLE WITH VISUAL EFFECTS - Google Patents

Abstract

The present invention relates to a blow molded article obtained from blow molding a preform made by parallel flow co-injection, having a wall formed by 3 layers in at least one region, with the outer layer being transparent. and the inner layer comprises an effect pigment visible through the transparent layer. The articles according to the invention have an improved gloss, low opacity and greater resistance to delamination than the previous articles. The invention also relates to preforms for manufacturing the described articles and methods for producing preforms and articles.

Description

FIELD OF INVENTION

[0001] The present invention relates to blow molded articles with effect pigments showing high gloss, low opacity and high resistance to delamination. The invention also relates to preforms for producing such articles and to methods for producing such preforms and articles.

BACKGROUND OF THE INVENTION

[0002] Blow molded articles made of thermoplastic materials such as polyethylene terephthalate (PET) and obtained from stretch blow injection of an injected preform (stretch blow molded articles, also called ISBM articles) are popularly used in various industries, including the cosmetics, laundry and food industries. In particular, containers for such fields and, in particular, bottles for liquid products are produced in this way. For such articles, having a shiny, pearlescent and/or metallic appearance is particularly desirable as it is attractive to users and tends to connote a superior quality product.

[0003] In order to obtain such an appearance, so-called "effect pigments" were developed. Materials marketed as "effect pigments" are pigments that impart additional color effects such as angular color dependence (iridescence, color shift, luster) or texture when applied to an application medium. These pigments are predominantly composed of platelet-shaped particles that tend to orient themselves in a direction parallel to the surface to which they are applied. The optical effects of these pigments (including luster, pearlization, iridescence, metallic effect) arise from the reflection of incident light on the smooth surface of the pigment platelets.

[0004] Effect pigments work well when applied to a solid surface because their particles such as platelets spontaneously orient themselves in a direction parallel to the surface to which they are applied. However, the introduction of effect pigments into large-scale blow molding operations has been considered more problematic and, in fact, effect pigments do not find wide industrial application in this field, especially when considering containers for liquid products that require be mass-produced quickly and at low cost.

[0005] Effect pigments can be applied to blow molded articles using standard coating application techniques such as painting or printing, but this adds additional complexity, costs and problems such as the need for varnishing that are unrealistic in mass production of blow molded articles. A relevant issue in introducing effect pigments into a blow molding manufacturing process is that the pigment particles remain dispersed within the article wall in a largely random orientation so that their effect is reduced.

[0006] An additional problem (partly linked to the misorientation of the particles of a blow molded article) is that blow molded articles comprising effect pigments have low gloss and a high opacity. Without sticking to theory, it is believed that this is due to the irregularity of the external surface of the articles when the effect pigments are present, possibly due to the random orientation of the platelet-shaped particles that, in part, will be exposed on the surface of the article in all guidelines.

[0007] A possible solution to the gloss problem may be to produce a preform and a resulting container with an inner layer comprising a pearlizing agent and an outer layer being transparent and comprising a dye. Preforms are generally manufactured using two-step methods, that is, a method where the materials that make up the various layers are introduced in sequence. A suggested process may include co-molding/overlay molding, i.e. a process in which the various layers are molded one over the other in subsequent steps and two co-injection steps with material from an outer layer being injected first into the mold cavity and is subsequently followed by the material of an inner layer. However, we have observed that in certain cases this construction method leads to poor mechanical properties of the finished article, so that the layers can separate during use (delamination).

[0008] Therefore, there is still a need to find a better way to provide visual benefits to an article produced by blow molding, while keeping the process simple, low-cost and scalable for mass manufacturing and in which the resulting article is resistant to delamination.

SUMMARY OF THE INVENTION

[0009] The present invention relates to a blow molded article having a hollow body defined by a wall, the wall having an inner surface and an outer surface, the wall being formed in at least one region by 3 layers, one layer A including the outer surface of the wall in that region, a layer B including the inner surface of the wall in that region, and a layer C sandwiched between layers A and B, the three layers A, B and C together composing the entire wall of the article in that region. region, said article being obtained by blow molding a preform made through a parallel flow co-injection of 2 or more streams and one or more streams forming layers A and B and the remaining streams forming layer C , with layer A being transparent and layer C comprising a pigment with an effect visible through layer A.

[0010] The present invention also relates to a preform that can be blow molded to obtain such an article and to methods of manufacturing that article and the preform.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Although the specification ends with claims that particularly indicate and distinctly claim the subject matter of the present invention, it is believed that this can be more readily understood from the description below, taken in conjunction with the attached drawings, in which:

[0012] Figure 1A is a schematic view of an injector arrangement where the nozzles are concentric;

[0013] Figure 1B is a schematic cross-section of an injector arrangement that is off-center;

[0014] Figure 1C is a schematic cross-section of an injector arrangement that is off-center;

[0015] Figure 1D is a schematic cross-section of an injector arrangement for producing preforms with two concentric injection nozzles;

[0016] Figure 1E is a schematic cross-section of an injector arrangement for producing preforms with two parallel injection nozzles;

[0017] Figure 1F is a schematic cross-section of an injector arrangement for producing preforms with two off-center injection nozzles;

[0018] Figure 2 schematically represents a bottle as shown in an enlarged schematic cross-section thereof with layers A, B and C;

[0019] Figure 3 is a photograph of a multilayer bottle with effect pigments under a transparent layer;

[0020] Figure 4A is an image obtained by high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) at the A/C interface (attachment layer) of Example G;

[0021] Figure 4B is a region-wide elemental map for Cl from Example G;

[0022] Figure 4C is an elemental map over the entire region for Ti from Example G;

[0023] Figure 4D is a line scan with EDS (Energy Dispersive X-ray Spectroscopy) of Kα of Ti and Cl from Example G;

[0024] Figure 5A is an image obtained by transmission scanning electron microscopy (STEM) showing the interface/attachment layer of Example B;

[0025] Figure 5B shows a graph representing a line scan with EDS for Kα of N from Example B;

[0026] Figure 6 is a line scan with confocal Raman microspectroscopy across its entire cross section of the wall in Example D;

[0027] Figure 7A is an image obtained by scanning electron microscopy (SEM) of the COC/PET surface of Example C;

[0028] Figure 7B is an image obtained by scanning electron microscopy (SEM) of the PEN/PET surface of Example D;

[0029] Figure 7C is an image obtained by scanning electron microscopy (SEM) of the LCP/PET surface of Example F;

[0030] Figure 7D is an image obtained by scanning electron microscopy (SEM) of the Nylon/PET surface of Example B; It is

[0031] Figure 8 describes the measurement naming system used to determine C*, L* and h° when at different viewing angles when illuminated at 45°.

DETAILED DESCRIPTION OF THE INVENTION Definitions

[0032] The term "article", as used herein, refers to an individual blow-molded hollow object for use by a consumer, for example, a container suitable for containing compositions. The article may be a container, with non-limiting examples thereof including a bottle, an inverted plastic tube, a pitcher, a mug, a lid, a tube, and the like. In some examples, the container is a flask. In the case of containers, layer A may include the outer surface of the container and layer B may include the inner surface of the container. The term "container" is used to broadly include elements of a container, such as a closure system or dispenser of a container. The compositions contained in such a container may be any of a variety of compositions, including, but not limited to, detergents (e.g., laundry detergents, fabric softeners, dish treatments, skin and hair care). ), beverages, powders, paper (e.g., tissue paper, baby wipes), beauty care compositions (e.g., cosmetics, lotions), medications, oral care (e.g., toothpaste, mouthwash), and similar. The container can be used to store, transport and/or dispense the compositions contained therein. Non-limiting volumes that can be contained within the container are in the range of 10 mL, 100 mL, 500 mL, or 1,000 mL to 1,500 mL, 2,000 mL, or 4,000 mL.

[0033] The term "blow molding" refers to a manufacturing process by which plastic articles containing hollow cavities are formed and are generally suitable for containing compositions. The blow molding process typically begins with at least partial melting or melting or heat softening (plasticization) of the thermoplastic material and forming it into a parison (when using extrusion blow molding) or preform (when using extrusion blow molding). uses injection blow molding or injection stretch blow molding), wherein said parison or preform may be formed by a molding or shaping step, such as by extrusion through a mold head or injection molding. The parison or preform is a piece like a plastic tube with a hole at one end through which compressed air can pass. The parison or preform is held inside a mold and air is pumped into it, sometimes along with mechanical stretching of the parison or preform (known as "stretch blow molding"). The parison or preform can be preheated before air is pumped into it. The pressure pushes the thermoplastic outward so that it conforms to the shape of the mold that contains it. Once the plastic has cooled and hardened, the mold is opened and the part is ejected. In general, there are three main types of blow molding: extrusion blow molding (EBM), injection blow molding (IBM), and injection stretch blow molding (ISBM). The articles of the present invention are made by ISBM.

[0034] For use in the present invention, articles including "a" and "an", when used in a claim, are understood to mean one or more of what is claimed or described.

[0035] As used herein, the terms "comprise", "comprises", "comprising", "include", "includes", "including", "contain", "contains" and "containing" are intended to be not limiters, i.e. other steps or other ingredients that do not affect the final result can be added. The above terms encompass the terms "consisting of" and "consisting essentially of".

[0036] All percentages are percentages by weight based on the weight of the composition, except where otherwise indicated. All reasons are weighty reasons unless specifically stated otherwise. All number ranges include narrower ranges; the delineated upper and lower range boundaries are interchangeable to create additional ranges not explicitly delineated. The number of significant figures does not represent limitations on the quantities indicated, nor on the accuracy of the measurements. All measurements are understood to be made at about 25°C and under ambient conditions, with "ambient conditions" meaning conditions under about atmospheric pressure and about 50% relative humidity.

[0037] It should be understood that each upper numerical limit presented throughout this specification includes each of the lower numerical limits, as if such lower numerical limits were expressly written in this document. Each minimum numerical limit presented throughout the specification includes each of the upper numerical limits, as if such upper numerical limits were expressly written in this document. Each numerical range set forth in this specification includes each narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were expressly written herein.

[0038] The present invention relates to the field of blow molded articles that have a hollow body, such as containers and flasks, manufactured through a stretch injection blow molding process (ISBM article).

[0039] The ISBM process begins with a first step in which a thermoplastic material, typically a thermoplastic resin, is melted and injected into a preform mold to form a preform. When the preform is then released from the preform mold, it can be immediately processed but, more typically, it is cooled, stored and processed in a stretch blow molding station at a subsequent time and/or location. In a second step, the preform is introduced into stretch blow molding equipment where the preform is blow molded to its final shape through heating and stretching, typically using a core rod. In the ISBM process, unlike other blow molding processes, the preform is reheated to a sufficiently high temperature to enable the preform to be inflated so that biaxial molecular alignment is achieved on the side wall of the molded container. resulting blow. With the preform held in the neck, air pressure and, usually, a stretching rod, is used to stretch the preform in the axial direction and, optionally, also in the radial direction. In the case of bottles, the neck portion of the article may contain threads or flanges suitable for closure and are typically not altered from the preform, as the neck portion is often not extended. Articles obtained by stretch injection blow molding can be significantly longer than the preform. More information about stretch injection blow molding processes can be obtained from general textbooks, for example, "The Wiley Encyclopedia of Packaging Technology", Second Edition (1997), published by Wiley-Interscience Publication (see pages 87 to 89).

[0040] Many variations are possible for these steps as is known to those skilled in the art. For example, in some common cases, the preform is stretch blow molded within the same machine where the preform is made, but the two-step/two-machine process is much more common.

[0041] Articles made by the ISBM process (as well as the respective preforms made by injection molding) can be distinguished from similar articles made by a different process, for example, extrusion blow molding, by the presence of a marking port, that is, a small raised point that indicates the "port" where the injection was made. Typically, in the case of containers and bottles, the "port mark" is present at the bottom of the article.

[0042] The articles and preforms according to the invention are typically made of thermoplastic materials, typically comprising thermoplastic resins.

[0043] An article of the present invention may comprise more than 50% by weight, alternatively more than 70% by weight, alternatively more than 80% by weight, alternatively more than 90% by weight of a thermoplastic resin, selected from the group consisting of polyethylene terephthalate (PET), polyethylene terephthalate (PETG), polystyrene (PS), polycarbonate (PC), poly(vinyl chloride) (PVC), polyethylene naphthalate (PEN), polyethylene terephthalate ( PCT), glycol modified copolymer PCT (PCTG), cyclohexane dimethanol terephthalic acid copolyester (PCTA), polybutylene terephthalate (PBCT), acrylonitrile styrene (AS), styrene butadiene copolymer (SBC), or a polyolefin, e.g. one of low-density polyethylene (LDPE), linear low-density polyethylene (LLPDE), high-density polyethylene (HDPE), polypropylene (PP), polymethylpentene (PMP), liquid crystalline polymer (LCP), cyclic olefin copolymer (COC ), and combinations thereof. In some examples, the thermoplastic resin is selected from the group consisting of PET, HDPE, LDPE, PP, PVC, PETG, PEN, PS and a combination thereof. In one example, the thermoplastic resin may be PET.

[0044] Recycled thermoplastic materials can also be used, for example, post-consumer recycled polyethylene terephthalate (PCRPET), post-industrial recycled polyethylene terephthalate (PIRPET) and/or regrind polyethylene terephthalate.

[0045] The thermoplastic materials described here can be formed through the use of a combination of monomers derived from renewable sources and monomers derived from non-renewable sources (for example, petroleum). For example, the thermoplastic resin may comprise polymers produced entirely from bioderived monomers, or comprise polymers produced partially from bioderived monomers and partially from monomers produced from petroleum derivatives.

[0046] The thermoplastic resin used here can have a relatively narrow weight distribution, for example, PE with metallocene polymerized using metallocene catalysts. These materials can improve the brightness of the item. Metallocene thermoplastic materials can, however, be more expensive than most raw materials. Therefore, in an alternative embodiment, the article is substantially free of expensive metallocene thermoplastic materials.

[0047] The blow molded articles of the present invention are multilayer articles in the sense that at least one region of the wall defining their hollow body comprises a layer A, including the outer surface of the wall in that region, a layer B including the inner surface of the wall in that region and a layer C pressed between layers A and B, where the three layers together form the entire wall of the article in that region. The multilayer region (i.e., the region comprising layers A, B and C) may constitute a large part of the wall surface of the article, alternatively more than 60%, alternatively more than 80%, alternatively more than 90% for so that its benefits can be extended over a larger portion of the article. In some cases the multilayer region may extend to the entire wall of the article.

[0048] The thickness of the article wall in the region formed by the three layers can be from 0.2 to 5 mm. The relative thickness of the three layers may vary. However, in some examples, layer C may have a thickness that may be between 5% and 40% of the total wall thickness of the article.

[0049] It has surprisingly been found that reducing the thickness of the C layer can be associated with improving the article's opacity and optical properties, even when the total wall thickness of the article is the same and the pigment content in the article is the same. total is not changed. Without being limited by theory, it can be seen that a narrower C layer contributes to the effect pigment particles being tightly packed together, which results in a more parallel orientation of the largest pigment surface parallel to the outer surface. Furthermore, the narrower C layer corresponds to the greater blade shear during the injection process towards preform production, which also contributes to a more consistent orientation of the largest particle surface parallel to the external surface of the article.

[0050] The hollow article may comprise a layer with an effect pigment (e.g., a layer C) which may comprise from about 10% to about 50% of the total wall thickness, alternatively from about 15% to about from 45% of the total wall thickness, and alternatively from about 20% to about 40% of the total wall thickness.

[0051] Layer A may be transparent, and layer C may comprise a pigment with an effect visible through the transparent layer A. The advantages in the appearance of the article are largely independent of the nature of the B layer. However, the B layer may be made of the same material as the A layer and therefore be transparent as the A layer. The B layer may also help to improve the strength and resilience of the bottle.

[0052] "Effect pigments" are marketed as such by major pigment suppliers such as Merck® or BASF®. Effect pigments may include "metallic effect pigments" and "special effect pigments". Metallic effect pigments can include metallic cores, such as aluminum. They can create a metallic shine through the reflection of light on the surface of the metal platelets, when they are parallel aligned in their application system. Metallic effect pigments may include metallic platelets coated with inorganic oxides such as silica, titanium dioxide, iron oxide and other oxides. Special effect pigments include all other platelet effect pigments that cannot be classified as "metallic effect pigments". These are typically based on a substrate that has platelet-shaped crystals (or particles), such as mica, borosilicate glass (natural or synthetic), alumina flakes and/or silica flakes. These platelet-shaped particles are typically coated with oxides. In some examples, special effect pigments may be "pearling pigments" (also called "pearlescent luster pigments"). "Interference pigments" are also suitable. Interference pigments are defined as special effect pigments whose color is generated completely or predominantly by the phenomenon of light interference.

[0053] The content of the effect pigment can be a layer of typically 0.01% to 5%, by total weight of the layer.

[0054] In addition to or instead of effect pigments, the wall of the article may contain opacifying pigments.

[0055] Opacifying pigments can include opacifiers, opaque absorption pigments and combinations thereof.

[0056] Non-limiting examples of opacifiers may include titanium dioxide, calcium carbonate, silica, mica, clays, minerals and combinations thereof. Opacifiers may be any domain/particle with refractive index suitably different from Thermoplastic Materials (e.g., PET, which may include poly(methyl methacrylate), silicone, liquid crystalline polymer (LCP), polymethylpentene (PMP), air, gases etc.). Additionally, opacifiers may appear to be white due to light scattering or black due to light absorption, as well as shadows in the space between them, as long as they block the transmission of most light to the underlying layer. Non-limiting examples of black opacifying pigments include carbon black and black organic pigments such as Paliogen® Black L 0086 (BASF).

[0057] Opaque absorption pigments may include particles that provide color and opacity to the material in which they are present. Opaque absorption pigments can be inorganic or organic particulate materials. All absorption pigments can be opaque if their average particle size is sufficiently large, typically greater than 100 nm, alternatively greater than 500 nm, alternatively greater than 1 micrometer, and alternatively greater than 5 micrometers. Absorption pigments can be organic pigments and/or inorganic pigments. Non-limiting examples of absorption organic pigments may include azo and diazo pigments such as lacquer-based azo and diazo, Hansas, benzimidazolones, diarylides, pyrazolones, yellows and reds; polycyclic pigments such as phthalocyanines, quinacridones, perylenes, perinones, dioxins, anthraquinones, isoindolines, thioindigo, diaryl or quinophthalone pigment, black aniline and combinations thereof. Non-limiting examples of inorganic pigments may include titanium yellow, iron oxide, ultramarine blue, cobalt blue, chromic oxide green, lead yellow, cadmium yellow and cadmium red, carbon black pigments and combinations thereof. Organic and inorganic pigments can be used individually or in combination.

[0058] The term "layer" in the context of the present invention, referring to layers A, B and C, includes the possibility that each of layers A, B and C is uniform or is made from two or more sublayers. If layer A is made of two or more sublayers, the entire layer A may be transparent, as required by the invention. In the event that layer C consists of two or more layers (e.g. C1 and C2), it may be sufficient for the underlayer facing and being in direct contact with layer A to contain effect pigments as required to satisfy the attribute that layer C contains an effect pigment visible through layer A. Additional sublayers of layer B or C may include, for example, gas barrier layers. Layer thickness can be measured by the layer thickness test method described later in this document.

[0059] A layer is considered "transparent" in the context of the invention if that layer has a total luminous transmittance of 50% or more and a reflected opacity of less than 5 opacity units. The total luminous transmittance is measured in accordance with the ASTM D1003 method, and the reflected opacity is measured in accordance with the ASTM E430 method.

[0060] The multilayer articles according to the invention are obtained by blow molding a co-injected preform, and the preform can be obtained through parallel flow co-injection.

[0061] Although a large part of the disclosure relates to the construction of the preform, it will be understood by one skilled in the art that any given structure, composition or sequence of layers in the preform will be reproduced in the finished blow molded article. During the stretch blow molding operation, the preform can be stretched and thinned in all directions to form the finished article. Although the stretch may not be the same at all points, so that the finished article will not have the same thickness across its entire surface, the sequence and composition of the layers making up the wall of the preform and article will not be significantly changed.

[0062] Coinjection molding is a technology widely used in the production of preforms. Its most common application is used to produce gas barrier bottles where a barrier layer is arranged between two layers of plastic. Suppliers such as Milacron®, Husky® and others offer co-injection molding equipment that can be used to manufacture multilayer preforms for the articles of the present invention. During co-injection, the process can be controlled so that one layer forms the outer surface of the preform (and then the outer surface of the article after the stretch blow molding step), while one or more layers can be superimposed on the first layer towards the inner portion of the preform. These additional layers can be controlled so that they can extend over the entire surface of the article or only over portions thereof. For example, in the case of a plastic bottle, the second and optionally subsequent layers may extend only along the body of the bottle and be absent at the neck and/or bottom of the bottle. Alternatively, in one example, a stream of material may be divided before being injected into the mold so that it can form both the inner and outer layers of the preform (layers A and B) at the same time, and one or more additional streams may form additional layers between the inner and outer layers.

[0063] Co-injected preforms can be obtained with two different methods, "step flow co-injection" and "parallel flow co-injection". In the step-flow co-injection method (such as the method described in the cited patent application WO2014/022990), thermoplastic resins intended to form the different layers of the preform are injected one after the other. There is a similar procedure called "overlay molding", in which a layer is molded on top of or within a previously molded layer. On the contrary, in the parallel flow co-injection method, the thermoplastic resins intended to form the different layers of the preform are injected essentially at the same time. For the purpose of the present invention, a co-injection method is intended to be "parallel flow" if the injection of all streams of thermoplastic material forming the preform begins within 5 seconds of each other.

[0064] In the present invention, the preform for blow molded articles can be made using a parallel flow co-injection process. The applicant has surprisingly observed that containers obtained by blow molding a preform made in parallel flow co-injection have improved gloss, low opacity and improved delamination resistance over containers made by a parallel flow co-injection process. phases.

[0065] The article may have a location on the external surface with a brightness of 20° greater than or equal to 30 GUs, greater than or equal to 40 GUs, greater than or equal to 50 GUs, greater than or equal to 60 GUs, greater than or equal to 70 GUs and/or greater than or equal to 75 GUs. The bright region may have a location with a 20° brightness of about 30 to about 120 GUs, from about 65 GUs to about 115 GUs, from about 70 to about 110 GUs, from about 90 GUs to around 110 GUs. The 20° gloss can be determined by the gloss test method described below.

[0066] The article may have a location on the external surface with a surface roughness of < 1 μm, alternatively < 0.5 μm, alternatively < 0.25 μm and alternatively < 0.1 μm. Surface roughness can be determined with the root mean square roughness test method described below.

[0067] The article may have a location on the outer surface with an opacity of ^30, alternatively ^20, alternatively ^15, alternatively ^10, alternatively ^5, alternatively ^3 and alternatively ^2. The article may have a location on the outer surface with an opacity of from about 0 to about 30, alternatively from 0 to about 20, alternatively from 0.5 to about 15, alternatively from 0.8 to about 10, and alternatively from 1 to about 5 Opacity can be determined by the opacity and reflection method, described below.

[0068] The article may have a location on the outer surface with an opacity anisotropy of < 1, alternatively ^ 0.9, alternatively ^ 0.8, alternatively ^ 0.7 and alternatively ^ 0.6. Opacity can be determined by the opacity and reflection method, described below.

[0069] As mentioned above in parallel flow co-injection equipment, the thermoplastic materials that make up the preform are injected into a preform mold using injector nozzles, with each nozzle providing a stream of thermoplastic material. For the present invention, the currents may all be initiated in parallel flow as defined herein.

[0070] The injectors can be arranged in several different ways, including the arrangements shown in Figures 1A to 1C. The arrangement of the injection nozzle can enable the manufacture of preforms with different characteristics and different layouts of the multilayer region. For example, a useful nozzle arrangement for producing the preforms for the present invention is a concentric nozzle, e.g., one in which the nozzle that delivers the thermoplastic material to layer C (stream I) is disposed within a nozzle greater than delivers the thermoplastic material to layers A and B (stream II) (see Figure 1A). In this design the thermoplastic material for layers A and B is typically the same so that a single resin flows into a nozzle and the material for layer C forms a layer disposed between two layers of material A/B.

[0071] The arrangement of the injector nozzles in Figure 1A can result in two concentric streams of molten thermoplastic components resulting from concentric nozzles C and A/B. The outer nozzle A/B may dispense stream II, which may include a thermoplastic composition that eventually forms the article's transparent outer layer A and the inner layer B, as shown in the enlarged schematic cross-section in Figure 2. The inner nozzle C corresponds to stream I, which may include a molten combination of thermoplastic resin and effect pigment that eventually forms the pigmented layer C of the article, as shown in the enlarged schematic cross-section in Figure 2.

[0072] Different nozzle arrangements can result in different flow patterns of streams I and II. Figures 1B and 1C show injector nozzles A and C that are off-center (not concentric or inclined). The external nozzle C can dispense current II and the internal nozzle C can dispense current I. In Figure 1B, the placement of the injector nozzle A and C can enable a thicker layer A, which comprises the external surface of the article. In Figure 1C, the positioning of injector nozzles A and C can allow for a thinner layer A and a thicker layer B, which comprises the internal surface of the article. To obtain this standard current, several methods can be used. Processes with non-concentric nozzles require the central nozzle to be positioned off-center, while processes with valve pin plates would adjust the profile creating preferential flow displacement. The prone position in Figure 1B may enable more material A to flow to the outside of the preform, which may result in better visual effects of the article.

[0073] Table 1 below includes examples of containers with the container wall thickness and the thickness of each layer and the total % of each layer. Table 1 *Additional details regarding Examples 1 and 2 are in Table 4, later in this document.

[0074] In examples where the nozzle is not off-center, there may be approximately equal amounts (e.g., within about 10% of each other) of material in the layer forming the outer surface (layer A) and the layer forming the outer surface. forms the inner surface (layer B). However, when the nozzle is prone, as described in Figure 1B, the layer that forms the outer surface (layer A) may be larger than the layer that forms the inner surface (layer B), for example, layer A may be at at least 20% greater than layer B, alternatively at least 30% greater, alternatively at least 40% greater, alternatively at least 50% greater, alternatively at least 70% greater and alternatively at least 80% greater.

[0075] Regardless of the placement of the nozzle, the hollow article may comprise a layer forming the outer surface (layer A) which may comprise from about 30% to about 70% of the total wall thickness, alternatively from about 35%. to about 65% of the total wall thickness, and alternatively from about 40% to about 60% of the total wall thickness.

[0076] The positioning of chain I is selected considering the desired properties of the final article. Processes utilizing concentric currents, similar to the nozzle arrangement in Figure 1A, can produce an article with increased brightness and appearance of depth relative to articles made by a single injector that produces a monolayer article. Some layer configurations on the wall can also improve barrier properties.

[0077] Figure 1B shows a nozzle arrangement where current I is biased inward, which can produce an article with an appearance of even greater depth and chroma compared to articles made using concentric currents, so similar to the nozzle arrangement in Figure 1A. Enhanced chroma may be evident from normal viewing by the observer (i.e., the surface of the article is perpendicular to the observer). However, the angle-dependent effects can also be improved by modifying the position of current I (and increasing the thickness of the outermost transparent layer). Specifically, a greater flop effect can be observed when the object surface is viewed at oblique/specular angles to the normal angles due to the length path of light through the outer A layer.

[0078] Additionally, stream II may contain a transparent dye or toner, the color intensity or chroma may be increased compared to a depicted process that creates a layer A and a layer B of approximately equal thickness, such as the article produced in Figure 1A. Similarly, if the position of the observer remains constant, angle-dependent effects can be observed due to the curvature of the article in different regions of the article. This is true because different regions may have different appearance, such as chroma, lightness, etc., even though all of these regions contain the same pigment/particle load. Additionally, by increasing the thickness of layer A, it may be possible to decrease the amount of dye/toner required to obtain a desired appearance.

[0079] Figure 1C shows a nozzle arrangement where current I is biased outward, resulting in a narrower layer A, which can produce an article with lower gloss and less depth effect while increasing the matte finish compared to processes that use concentric currents, similar to the nozzle arrangement in Figure 1A. The surface may also have increased surface roughness due to the presence of pigment particles near the outermost surface of the article.

[0080] Alternatively, when layer C is formed by two or more sublayers, the thermoplastic material that makes up these sublayers can be supplied by several nozzles that are in turn concentric (see Figure 1D) or parallel (see Figure 1E) or inclined (see Figure 1F). These different arrangements make it possible to introduce additional functional sublayers in C such as, for example, a gas barrier layer through nozzle C1/C2 in Figure 1D or nozzle C1 and/or C2 in Figures 1E and 1F. In one example, the functional sublayer may be free or substantially free of pigments/dyes.

[0081] In another example, the functional sublayer, in particular, the layer formed by nozzle current C2 in a configuration as in Figure 1E and 1F or C3 in a nozzle configuration as in Figure 1D, may include a dark dye and /or a dye and/or a black pigment. In this example, the layer formed by the nozzle current C1 (in a nozzle configuration as in Figure 1E and 1F) or C1/C2 (in a nozzle configuration as in Figure 1D) may include the effect pigment. This can place the dye or black/dark pigment closer to the hollow body of the article, enabling the absorption of transmitted light, and thus increasing the portion of reflected light. Many effect pigments are manipulated to reflect a portion of visible light by interfering light rays, while the unreflected portion is transmitted through the effect pigment platelet. Transmitted light often undergoes multiple scattering events before being reflected back to the observer. This transmitted, scattered and reflected light mixes with the interference color to produce a less chromatic, less brilliant color effect. By positioning a black layer behind the effect pigment layer, this mixture is eliminated, thus enabling the observer to see the chromatic and lustrous colors produced by the reflection of the interference.

[0082] Figure 2 shows hollow article 1, in this example the hollow article is a container, specifically a bottle. The hollow article 1 includes the hollow body 25 defined by the wall 3 with an inner surface 5 and an outer surface 6. The enlarged cross-section of the wall of the article 3 has three layers. The wall can be formed without adhesives (or substantially free of adhesives) by ISBM. Layer C may comprise effect pigments which may be visible through transparent layer A (A) from the outside of the hollow article. Layer A (A) can be colored or colorless. Layer B (B) can be of the same material as layer A (A).

[0083] It has been discovered that, during the production of preforms for the present invention, strict control of temperatures is beneficial for the regularity of the layers. Temperature can have a significant impact on the viscosity of thermoplastic material. In one example, the material for layer C (stream I) may be injected at a lower temperature than the material for layers A and B (stream II). In another example where the resin for layers A, B and C may contain PET, the material for layer C (stream I) may be injected at a temperature similar to that of the material for layers A and B (stream II). The temperature range of the layer A and B material (stream II) may be between about 290 and about 305°C, and alternatively, from about 240°C to about 305°C, as measured at the injection point. . In one example, the temperature of the material of layers A and B (stream II) may be about 280°C, measured at the injection point. The material for layer C (stream I) may be at a temperature of about 260°C to about 310°C and, alternatively, of about 260°C and about 275°C, as measured at the injection point. . In one example, the temperature for layer C material (stream I) may be greater than or equal to 280°C, as measured at the injection point. This lower temperature and higher viscosity contribute to better and more uniform layer formation. The difference between the viscosity of stream I and stream II can be well monitored and adjusted to avoid poorly formed layers or flow anomalies. In some examples, instabilities may be desirable to create unique patterns on the surface of the bottle.

[0084] Another process parameter that can be controlled during co-injection of the preforms is the pressure of the resin streams measured along the distributor line that supplies the injection nozzle. The stream (or streams) containing the material for layers A and B (stream II) may be maintained in a range between about 25 bar and about 400 bar, and alternatively between about 150 and about 400 bar, while the current with lower temperature/higher viscosity of layer C (current I) can be maintained in a range between about 1000 and about 1600 bar, alternatively between about 1000 and 1400 bar.

[0085] In order to preserve the transparency of the outer layer, it is beneficial to quickly cool the preform as soon as it is formed and also quickly cool the article after the stretch blow molding operation. This is because prolonged exposure to temperatures close to the glass transition temperature (Tg) of the resin can promote crystallization of the resin, which, in turn, can be detrimental to transparency. Rapid cooling makes it possible to preserve as much of an amorphous structure as possible that has greater transparency.

[0086] Figure 3 is a photograph of a bottle with a wall composed of several layers, for example, the A-C-B configuration described here. Layer A is transparent and colored and layer C comprises the effect pigment. This combination of layers can give the bottle in Figure 3 a very shiny, metallic, luminous and/or sparkling appearance. Figure 3 has a front side that is not flat and has a half-ellipse apex that is highly reflective on one side and much less reflective on the other, creating an eye-catching shadow on the front surface of the bottle.

[0087] In the article of the present invention, layer C, which comprises the effect pigments, can be visible through layer A from the outside of the hollow article. Layer A can be colored or colorless. Layer A can be transparent. Layer A may be essentially free or free from pigments and/or pigment particles or particles having their greatest size between 150 nm and 5000 nm (where essentially free means that layer A may contain less than 1% by weight of of pigments or particles with their largest dimension between 150 nm and 5000 nm). Layer A, if desired, can be colored using a soluble dye or a transparent pigment in the thermoplastic material that makes up the layer, in order to obtain more aesthetically pleasing effects. Pigments become transparent in a matrix when the difference between the refractive index of the pigment (which depends on wavelength) and that of the matrix is small, and when the particle size of the pigment is below that which occurs in the dispersion of Mie (typically a larger particle size of about 100 nm or less).

[0088] The presence of a smooth and transparent outer layer of the container allows layer C, which comprises the effect pigments, to be visible from the outside and, at the same time, provides the bottle with a high level of gloss. Without being bound by theory, it is also believed that the presence of a shiny surface at a distance from the opaque surface of layer C, which comprises the effect pigments, can contribute to a premium appearance of the article itself. This may be the case due to the existence of two slightly offset focal points, which provide the viewer with an impression of depth.

[0089] We previously mentioned the problem of the orientation of effect pigment particles, which can be platelet-shaped when the article wall is formed through an ISBM process. It has surprisingly been discovered that, in articles according to the invention, the effect pigment particles in layer C are predominantly oriented so that their face is parallel to the surface of the article to a higher degree than that of monolayer articles. Without sticking to theory, it is believed that this may be due to a combination of factors. One factor that may contribute to this may be the fact that in monolayer articles the effect pigments are dispersed throughout the wall of the article which is thicker (at par mechanical strength of the article) than the C layer sandwiched between the layers. A and B, as in articles according to the invention. In monolayer articles, the particles have more free space to rotate freely. On the contrary, in the case of a multilayer article according to the invention, layer C, where the effect pigments are confined, is much thinner, as it represents only a portion of the total thickness of the article. As a result, extension steps can contribute to optimal orientation of a higher percentage of platelet-like pigment particles.

[0090] It was also discovered that the tendency of platelet effect pigments to orient themselves parallel to the surface of the article persists, even when the article has an irregular shape. In this way, the article format can be used to further modify the visual effects generated by the article from the point of view of a person viewing it, depending on the orientation of the article when viewed. For example, an article that is predominantly cylindrical should have visual effects imparted by effect pigments that are relatively constant to the viewer, regardless of the article's orientation relative to its primary geometric axis. When the article is predominantly cylindrical, it can be rotated about its primary geometric axis without substantially modifying the visual effects, because the article is radially symmetric about the primary geometric axis, and the orientations of the effect pigments will be largely unchanged with respect to the viewer's point of view. Furthermore, in a substantially cylindrical bottle, the effect pigment platelets are expected to be oriented substantially perpendicular to the viewer's line of sight near the center of the article, and increasingly angled away from the viewer toward the edges of the article. article, as seen by the viewer. In this way, any optical effects that might depend on the reflection of incident light by the effect pigments would be directed toward the viewer near the center of the article, but directed away from the viewer at the edges of the article.

[0091] For example, visual effects such as glare, reflection and the like may be more pronounced towards the center of the article as seen, which may then interfere with other decoration and/or labeling of the article, which could be incorporated near the center of the article.

[0092] Alternatively, when the article is substantially non-cylindrical and the enhanced visual effects derived from an orientation of the platelet effect pigments, especially when combined with a transparent color layer A, may occur anywhere on the article, incorporating concave contours and convex in the general shape of the bottle. Such contours can help provide optical effects that occur at one or more specific viewing angles and/or one or more lighting angles.

[0093] Without sticking to theory, it is believed that the trajectory of the light ray incident on the article and the return to the observer can be affected by the curvature of the article so that the surface of the articles will receive angles of incidence where the light ray will interact mainly with layer A of transparent color, in relation to the normal angles where the light ray will interact with both layer A and layer C in the optimal orientation of the effect pigment platelets. Thus, an article of the present invention, which additionally comprises convex and concave portions, will create at least 3 distinct regions of appearance visible to the observer, without requiring rotation of the article and without requiring the observer to change his place of observation. These can be characterized as (a) a region of high chroma, which may be due to the ray trajectory confined to the A layer; (b) a region of high luminosity, which may be due to an optimal reflection of the effect pigment platelets; and (c) a region having a combination of these optical responses (which would be more typical for cylindrical articles).

[0094] It has also been discovered that the present invention produces a relatively high chroma at a viewing angle of -15° when illuminated at 45° to the surface normal. The -15° angle is important, as generally speaking, it is the angle of higher reflectance vision. Therefore, it may be preferred for the article to be viewed from this viewing location. Rather than requiring the article to be viewed from a specific angle, the preferred optical effect can be achieved by including a multiplicity of viewing angles through the incorporation of convex and concave features into the overall shape of the article.

[0095] Table 2, below, compares the chroma (C*), brightness (L*), hue (h°) and chroma change between the two viewing angles (ΔC*) of Example 3 with those Comparative Examples 7 and 8. C*, L* and h° can be determined by the chroma, brightness and hue test method described below. As described in Table 4 below, Example 3 has three layers of PET and the middle layer contains 4% pearl white satin masterbatch. As described in Table 6 below, Comparative Examples 7 and 8 have a single layer of PET comprising 4% and 6% pearl white satin masterbatch, respectively. Table 2

[0096] The chroma shift in Example 3 was significantly higher than the chroma shift in comparative Examples 7 and 8, although all three examples contain the master batch with at least 4% pearly white satin. The angular dependency chroma effect, demonstrated by the high ΔC* of Example 3, can be easily visible to consumers when they view the product, in particular, it can be eye-catching on the shelf. Angle-dependent chroma can have the effect of the item appearing to be different colors as a viewer passes the item or as the item passes the consumer. Achieving high C* in geometries where the effect pigment provides maximum or near-maximum L* is generally not achievable with single-layer designs.

[0097] The hollow article may have a C* (45 in -15) greater than 35, alternatively greater than 40, alternatively greater than 45, alternatively greater than 50, alternatively greater than 55 and alternatively greater than 60. The hollow article may have ΔC* (absolute value of the difference between C* (45 in -15) and C* (45 in 45)) of at least 9, alternatively at least 10, alternatively at least 13, alternatively at least 15, alternatively at least minus 20, alternatively at least 24, alternatively at least 27 and alternatively at least 29.

[0098] In one aspect, the center of the article, as viewed by the viewer, may be relatively flat, and free from such convex and concave features, to enable a product label and/or other mark or identification of the product without interference, while Portions of the article that are disposed toward the periphery of the article as viewed by the viewer may comprise more substantial contours such as ridges, valleys, and the like.

[0099] Such relatively flat portions, as well as such valleys and crests, can be characterized by the radius of curvature of the surface of the article taken in cross section. Said cross section may be taken perpendicular to the primary geometric axis of the article, or perpendicular to a geometric axis perpendicular to the primary geometric axis. Specifically, a relatively flat portion will have a relatively high radius of curvature and the peak of a ridge will have a relatively low radius of curvature. "Relatively high" and "relatively low" radius of curvature have meaning in relation to the radius of curvature of a circle of equal perimeter to the cross-section of the article under consideration.

[0100] When the contour is convex to the observer (e.g., the curved portion projects toward the observer), the center of curvature would be away from the observer relative to the surface of the article, and when the contour is concave to the observer (e.g., the curved portion projects away from the observer), the center of curvature would be toward the observer relative to the surface of the article. By convention, the convex contour can be considered to have a positive radius of curvature and the concave contour can be considered to have a negative radius of curvature.

[0101] A cylindrical article would have a constant radius of curvature when taken in cross-section perpendicular to the primary geometric axis. An uncurved or flat portion of the article would have an indefinite radius of curvature. In some examples, the article is non-cylindrical.

[0102] An additional advantage of the hollow containers of the invention is that it has surprisingly been found that these containers are more resistant to delamination. Delamination is a constant problem in the manufacture of hollow multilayer blow molded articles such as containers. Delamination can occur over time due to mechanical handling of the container, thermal stress, or mechanical stress. In other examples, delamination can occur at the interface between layers, causing the layers to separate, which can cause blisters and/or ripples beneath the outer surface. Without being bound by theory, it is believed that the parallel flow co-injection used here results in prolonged contact of the materials of the various layers while still in a molten or partially molten state. This ultimately leads to the formation of a transition region between the layers, with the layers being slightly interpenetrated. This transition region generates a strong connection between the layers and therefore makes it much more difficult to separate them, even without any adhesive at the interface.

[0103] Surprisingly, it was also discovered that multilayer articles according to the invention have a greater resistance to delamination not only in relation to articles obtained by blow molding of preforms produced by step flow co-injection or overlap molding in two stages, but also in relation to articles obtained from monolayer preforms.

[0104] In sequential injection molding processes (also known as 2-step overlap molding or co-molding), there is minimal mixing between the resins injected in each injection step, since the first resin is essentially cooled/cooled. solidified before the second resin is injected. This way, there is little or no flow/mixing and the material is more quiescent. Crystallization of one or both resins can also have an impact on bond strength. Slower cooling often results in some degree of crystallization, which is not desirable for the production of hollow articles with ISBM when the preform is heated and stretched. Optimizing bond strength while minimizing crystallization can be difficult to achieve using sequential injection molding, as the mold is often held at an elevated temperature for longer (hotter and longer than the single injection mold) and the low thermal conductivity at the interface of the first injected resin results in slower cooling of the second resin injected at and near the interface.

[0105] Parallel flow co-injection relies on at least two resin melt streams, each with a velocity greater than 0 during at least part of the mold filling process. Laminar and turbulent flow regimes have been described for parallel co-injection processes, where the laminar regime provides essentially no mixing between the streams and the turbulent regime provides excessive mixing where the domains of one resin stream mix within the stream of the second. resin. The laminar regime may provide unsatisfactory resistance at the interface. The turbulent region may also be undesirable, as this may create opacity (due to scattering of light between regions of different refractive indices). Furthermore, turbulent mixing decreases the alignment/orientation of pigment particles within the turbulent zone, thereby decreasing the desirable optical effect of several classes of pigments, including effect pigments.

[0106] Although it is not desired to adhere to a theory, the parallel co-injection process may have a flow regime in the transition zone, which may enable substantial mixing of parallel injected resins without resulting in any opacity. However, polymer resins may have some miscibility at melting temperature, so that when rapidly cooled by the injection molding process, different resins will remain mixed at the molecular level in the preform and article.

[0107] Table 3, below, compares the average starting load of Examples A to G. Example A is a comparative Example and was made by two-step overlap molding. Examples B to G were made by ISBM. All Examples A to G have a three-layer wall: layer A comprising the outer surface of the bottle; layer B comprising the inner surface of the bottle and a layer C situated between layers A and B. Table 3

[0108] The critical normal load method was used to determine the critical normal load for each Example. The type of critical normal load failure was determined by visual inspection and categorized as adhesive failure (A), cohesive failure (C), or partial cohesive failure (PC).

[0109] In all cases of parallel co-injection, the average starting charge is higher compared to the 2-step PET/PET/PET sample, even with substantially different resins used in layer B (nylon, COC (cyclic olefin copolymer ), PEN (polyethylene naphthalate), LCP (liquid crystalline polymer) and PET-G (post-consumer recycled plastic)).

[0110] In other words, the transition layer (fixing layer) appears to further strengthen the article wall relative to a monolayer execution. Delamination resistance is assessed by measuring the critical normal load in the three-layer region using the method described below in the test methods section. A higher critical normal load indicates a higher resistance to delamination. Articles according to the invention may have a critical normal load greater than 50 N. The critical normal load may be 70 to 120 N.

[0111] The average load at the beginning of the article may be greater than 30 N, greater than 40 N, greater than 50 N, greater than 55 N, greater than 60 N, greater than 65 N, greater than 70 N, greater than 80 N, greater than 85 N, and/or greater than 90 N, as determined by the critical normal load method, described below. The average starting load of the article may be from about 35 N to about 150 N, alternatively from about 30 to about 125 N, alternatively from about 50 N to about 100 N, and alternatively from about 55 N. at about 95 N, as determined by the critical normal load method, described below.

[0112] The thickness of the A/C interface (also called the fixing layer) was determined by the fixing layer thickness method, described below. The thickness of the A/C interface is the distance normal to the interface over which the unique element composition is changing between maximum concentration and minimum concentration.

[0113] The thickness of A/C or B/C (i.e., the fixation layer or transition layer) can be from about 500 nm to about 125 μm, alternatively 1 μm to about 100 μm, alternatively from about 3 μm to about 75 μm, alternatively from about 6 μm to about 60 μm, alternatively from about 10 μm to about 50 μm, as determined by the fixation layer thickness method, described below.

[0114] As there are no unique elements in the parallel co-injection PET/PET/PET sample (Example G), the master batch with 6% titanium dioxide (TiO2) was added to the stream that forms layers A and B and the 6% master batch containing black pigment comprising chlorine (Cl) was added to the stream forming layer C. This was used to generate the images in Figures 4A to 4D. This method (method A) was used to determine that Example G had an interface thickness of >15 μm.

[0115] Figures 4A to 4D indicate that there is an interface/attachment layer in Example G. Figure 4A is a high angle annular dark field (HAADF) STEM image at the interface A/C (attachment layer) of Example G. Figure 4B and Figure 4C are region-wide elemental maps for Cl and Ti. Figure 4B shows that there is a high concentration of Cl that decreases and Figure 4C shows that there is a low Ti content that increases. Figure 4D is an EDS (Energy Dispersive X-ray Spectroscopy) line scan of Kα of Ti and Cl. Figure 4D shows that Ti begins to increase as Cl decreases. The area where Ti and Cl are mixed indicates a fixation layer.

[0116] The thickness of the fixation layer for Example B (PET/Nylon/PET) was analyzed using method A. Figure 5A shows a STEM (scanning transmission electron microscopy) image showing the interface layer /fixing 30 between the PET layer 10 and the nylon layer 20.

[0117] In Example B, nitrogen was mapped/line scanned across the entire interface with EDS. Figure 5B shows a graph representing a line scan with EDS for Kα of N. The line represents Kα of N and shows that at a distance of 700 nm there is very little nitrogen (N) in the region (indicating the PET layer). As the EDS moves along the cross section of the wall, there is a steep transition indicating the fixing layer where the PET and nylon are slightly mixed. After the steep transition there is more N present (indicating the nylon layer).

[0118] The thickness of the fixation layer for Example D (PET/PEN/PET) was analyzed using method B. Figure 6 is a Raman line confocal scanning microspectroscopy across the entire cross section of the wall of the article using spectral features unique to PEN. Figure 6 also shows the presence of a fixation layer, which can be measured down to about 3 microns, as indicated in the figure. Note that Table 3, above, shows a range of 2 to 4 μm, as multiple fixation layer thicknesses were calculated and all were between 2 and 4 μm.

[0119] To determine the type of failure between layer A and C (e.g., adhesive failure, cohesive failure, or partial cohesive failure), samples A to G were flexed and peeled. The inner surface of the PET layer was frontally mounted and inspected by SEM and Figures 7A to D show these images obtained by scanning electron microscopy (SEM).

[0120] To obtain the images in Figures 7A to 7D, samples were prepared as follows: Vial wall regions were removed by cutting out a large region with a utility knife, then cutting it further down to about 1 x 2 cm using scissors or a single sharp Teflon coated blade. The cut-out portions are assembled with the outer surface of the bottle facing upwards at one end per standard SEM, by fixing with double-sided conductive tape (carbon or copper). The edges of the bottle part are painted with a small amount of conductive paste (carbon or silver) to ensure good electrical contact with the SEM tip. The tip-mounted sample is coated for about 100 seconds with fine gold by a good quality spray system such as the Denton Desk V (Denton Vacuum, Moorestown, NJ, USA). The thickness of the coating is determined by one skilled in the art, but is generally less than 100 seconds at about 38 mA, which is thick enough to prevent charging, but having as little impact on the surface texture as possible. The coated samples were immersed under high vacuum with an FEI Quanta 450 FEG in use at 2 to 5 kV acceleration voltage.

[0121] Figure 7A is a scanning electron microscopy (SEM) image of the COC/PET surface of Example C and Figure 7B is a scanning electron microscopy (SEM) image of the PEN/PET surface of Example C. Example D. Figures 7A and 7B show partial cohesive failure as there are regions of COC and PEN, respectively, still adhered to the PET surface.

[0122] Figure 7C is a scanning electron microscopy (SEM) image of the LCP/PET surface of Example F. The LCP/PET surface shows cohesive failure where failure occurs within the LCP layer and not at the interfaces PET/LCP/PET. Example F had one of the critical normal loads (85.9 N) compared to the other examples.

[0123] Figure 7D is an SEM image of the Nylon/PET surface of Example B. The Nylon/PET surface shows a clean surface with no identifiable regions of nylon still adhered to the PET. This was classified as an adhesive failure. Example B had the lowest critical normal load (18.5 N) compared to the other Examples made with the ISBM (Examples C to G).

[0124] In some Examples, layers A, B, and C are based on the same type of thermoplastic resin (e.g., PET). This can enable better interpenetration of layers at the interface due to their chemical compatibility and a more robust wall. For "based on the same type of resin", it is understood that layers A, B and C comprise at least 50%, alternatively at least 70%, alternatively at least 90% of the same type of resin. By "same type" of resin is meant the resin from the same chemical class, i.e. PET, is considered a single chemical class. For example, two different PET resins with different molecular weights are considered to be the same type including but not limited to PET and recycled PET. In another example, the PE and PP are the same type. A PET resin and a PP resin are not considered the same type. Different polyesters are also not considered the same type.

[0125] Layers A, B and C can be formed by the same thermoplastic resin (for example, PET) and can only be different for the type of dyes and pigments included.

Additional optional attributes

[0126] Articles according to the invention may comprise sublayers with various functionalities. For example, a container may have an underlayer of barrier material or an underlayer of recycled material between an outer thermoplastic layer and an inner thermoplastic layer. Such layered containers can be produced from multi-layer preforms according to common technologies used in the field of thermoplastic manufacturing. Barrier material underlayers and recycled material underlayers can be used in layer A (when they do not affect the transparency of layer A), B or C. In some examples, they will be present as underlayers of layers B or C and will be positioned towards the inner part of the container further away from layer A than the sublayer comprising the effect pigment which should be visible through layer A.

[0127] The article of the present invention may comprise, in any of its layers as long as the necessary properties of the layer are maintained, additives typically in an amount of 0.0001%, 0.001% or 0.01% to about 1% , 5% or 9%, by weight of the article. Non-limiting examples of the auxiliary ingredient include titanium dioxide, filler, curing agent, antistatic, lubricant, UV stabilizer, antioxidant, antiblocking agent, catalyst stabilizer, dyes, nucleating agent and a combination thereof.

[0128] Another aspect of the present invention relates to a hollow preform that can be blow molded to produce an article as described above. A hollow preform according to the invention is a preform for blow molding having a wall, the wall having an inner surface and an outer surface, the wall of the preform being formed in at least one region per three layers, a layer A' including the outer surface of the wall in that region, a layer B' including the inner surface of the wall in that region, and a layer C' sandwiched between A' and B', with the three layers A', B' and C' together make up the entire wall of the preform in that region, with said preform being obtained by the parallel co-injection of two or more currents and in which one or more currents form the layer A' and B' and the currents The remainder form layer C', where layer A' is transparent and layer C' comprises an effect pigment visible through layer A'.

[0129] As is evident to one skilled in the art, such a preform, once blow molded, will form an article according to the invention having layers A, B and C, with the layers of the preform forming the corresponding layers of the article, that is, A' will form A, B' will form B and C' will form C.

[0130] One skilled in blow molding will know how to modify the compositions and structure of the preform so as to obtain all of the optional and preferred attributes of the articles of the invention described above. The present invention also relates to a method for making a preform for blow molding which comprises the following steps of: a) providing a co-injection mold for manufacturing a preform b) co-injecting essentially at the same time (co-injection parallel) two or more chains of molten resin thus forming a complete preform, as described above, with one or more chains making up layer A' and B' and the remaining chains making up layer C, with layer A' is transparent and layer C comprises an effect pigment visible through layer A'.

[0131] A preform obtained with this method can be subsequently blow molded, including stretch blow molded, in order to obtain an article according to the invention.

[0132] In another aspect, the present invention relates to a blow molded article having a hollow body defined by a wall, the wall having an inner surface and an outer surface, the wall being formed in at least one region by 3 layers, a layer A including the external surface of the wall in this region, a layer B including the internal surface of the wall in this region and a layer C sandwiched between layers A and B, with the three layers A, B and C together composing the entire wall of the article in the region, layer A being transparent and layer C comprising an effect pigment visible through layer A, and said article being in the region where layers A, B and C are present has an importance for the Normal Critical Load, according to the method described herein, greater than 50 N. As explained above, such articles can be manufactured by blow molding a preform made with a parallel flow co-injection process.

Examples

[0133] Several vials were prepared, Ex. 1 to 3 are in accordance with the invention, Ex. 4 to 9 are comparative examples. These examples are described in Table 4 through Table 6, below. In the three-layer example, layer A comprises the outer surface, layer B comprises the inner surface and layer C is situated between layers A and B. Table 4: Examples Table 5: Comparative examples Table 6: Comparative examples PET Laser+® C (E60A) available from DAK Americas LLC Orange Master Lot: E-15796-2 Trans Orange Master Lot (Clariant NE21760074) Pearl White Satin Master Lot: X-14413-1 WHITE PEARL SATIN#2 (Clariant, NE02760182 ) Clear Gold Master Lot: E-15962-3 GOLD TONER V3 (Clariant NEG1760080) Clear Green Master Lot: E-15795-4 TRANS GREEN (ClariantNE61760150) Opaque White (Clariant Masterbatches, NE03642542) Opaque Black (Clariant Masterbatches, NE94760019) Table 7: Delamination performance

[0134] Delamination resistance is evaluated by measuring the critical normal load in the three-layer region using the method described below. A higher critical normal load indicates a higher resistance to delamination. Inventive Examples 1 and 2 exhibit higher critical normal load to delaminate compared to Comparative Example 9 (PET monolayer made with the same ISBM process) and Comparative Example 5 (bilayer made by "2-shot" overlay molding) . This shows how the structure of the invention is more resistant to delamination than a multi-layer overmolded bottle and also a single-layer bottle. This highlights the importance of improved adhesion between the layers present in vials manufactured with the parallel flow co-injection process. Table 8: Optical performance

[0135] The data shows that inventive example 3 has less surface roughness, higher specular reflectance, more gloss, lower opacity, and lower reflection smoothness than in comparative examples 7 and 8, which are monolayer bottles with PET resin and identical pigmentation. Table 9: Effect pigment transmittance

[0136] The data in the table above shows that a bottle according to the invention is overall more opaque than a comparative monolayer bottle with the same pigments, pigment content and thickness. The pearl layer (which has the effect pigment) is intended to be opaque and the level of opacity corresponds to the effectiveness of the amount of pigment used. Without sticking to theory, we believe that this is the result of a better orientation of the effect pigments (parallel to the plane of the article surface).

TEST METHODS Method for critical normal load (N) and depth of scratches in the failure region

[0137] Samples with dimensions of 100 mm in length and about 50 mm in width are cut from the main portion of the article wall. When the article does not allow the collection of a large sample, this shorter sample on a 1:2 width:length scale may be used. Smaller samples may lead to a less accurate measurement. Specimens should be as flat as possible or made flat by the use of a structure that keeps the specimen flat at least in the region where the scratch test is performed. For containers and vials, the sample is preferably removed from the vial label panel at least 50 mm in a direction away from the shoulder/neck or base regions. Cutting is done with a suitable razor blade or scalpel so that a larger region is removed, then cut further down to a suitable size with a new single-edge razor blade. If the sample readily delaminates upon removal from the vial, the sample is given a score of 0 N for the "Normal Critical Load".

[0138] The "Depth of Scratches in the Fault Region" for such a sample is measured as the thickness of the outer layer that has been delaminated. Thickness can be measured with a high-precision digital micrometer, such as a Shinwa 79523 Digital Micrometer which has an accuracy of +/- 0.003 mm. Samples that remain intact are subjected to scratch-induced damage using Scratch 5 from Surface Machine Systems, LLC and, in accordance with scratch test procedures (ASTM method D7027-13/ISO 19252:08), using a spherical 1 mm diameter, Initial Load: 1 N, Final Load: 125 N, Scratching Rate: 10 mm/s, and Scratching Length of 100 mm. For samples smaller than 100 mm, the Scratch Length can be reduced while maintaining the same initial and final load. This provides an estimate of the Normal Critical Load. Using this estimate, additional samples can be examined over a narrower load range to provide more accurate determination of the Normal Critical Load.

[0139] Scratch-induced damage is performed on both sides of the sample corresponding to the inner and outer surface of the vial. It is critically important that the sample is affixed to the sample stage through the use of double-sided foam-based tape, such as 3M Scotch® Permanent Mounting Tape (high-density double-sided polyurethane foam tape with acrylic adhesive with a total thickness of about 62 mils or 1.6 mm, UPC #021200013393)) on the underside of the sample. All samples are cleaned with compressed air before scratch testing.

[0140] The Failure Point is determined visually after completing the scratch test as the distance along the length of the scratch at which the onset of visible delamination occurs. Delamination introduces an air gap between the layers that is visible to the naked eye or with the assistance of a stereomicroscope by one skilled in the art. This is validated based on a minimum of three scratches per side of the sample (defined as the bottle cut above) with a standard deviation of 10% or less. The side with the lowest critical normal load is reported as the result of this method. The Depth of Scratches in the Fault Region is measured according to the ASTM D7027 method by locating the scratch at the point where the initiation of delamination occurs. The critical normal load (N) is defined as the Normal Load recorded at the location determined to be the Failure Point. A Laser Scanning Confocal Microscope (Keyence VK 9700K) and VK X200 Analyzer Software is used to analyze scratch-induced damage, including Failure Point, Scratch Width, and Scratch Depth.

Average panel wall thickness

[0141] Panel wall thickness is measured with a digital micrometer such as a Shinwa 79523 digital micrometer with an accuracy of +/- 0.003 mm by having at least 2 locations of the panel wall sections cut close to the midpoint of the vial height .

Layer thickness

[0142] Layer thickness is measured by the MicroCT scanning method (described below) with image analysis where the effect pigment layer is defined as containing 95% of the pigment.

MicroCT scanning method

[0143] The vial samples to be tested are viewed using a microCT x-ray scanning instrument capable of scanning a sample with dimensions of at least 5 mm x 5 mm x 3 mm, as a single data set with the contiguous voxels. An isotropic spatial resolution of 1.8 mm is required in data sets collected by scanning via microCT. An example of suitable instrumentation is the SCANCO Systems model μ50 microCT tomograph (SCANCO Medical AG, Brüttisellen, Switzerland) operated with the following settings: 55 kVp energy level at 72 μA, 3600 projections, 10 mm field of view, 1000 ms integration time, a mean of 10, and a voxel size of 1.8 μm.

[0144] The test samples to be analyzed are prepared by cutting a rectangular piece of plastic from the wall, preferably with a label panel region with an X-Acto® scalpel then additionally trimming the sample to approx. 5 mm wide using a fine-toothed X-Acto® saw carefully to avoid causing cracks. The sample is positioned vertically with the mounting foam material and placed in a cylindrical plastic scanning tube and fixed inside the microCT scanner. The sample is positioned vertically with the mounting foam material and placed in a cylindrical plastic scanning tube and fixed inside the microCT scanner. Image acquisition setups that are unable to obtain this contrast discrimination or the necessary spatial resolution are unsuitable for this method. Scans of the plastic sample are captured so that a similar volume of each sample with its gauge is included in the data set.

[0145] Software for performing dataset reconstructions to generate 3D images is provided by the manufacturer of the scanning instrument. Software suitable for subsequent image processing steps and quantitative image analysis includes programs such as Avizo Fire 9.2 (Visualization Sciences Group/FEI Company, Burlington, Massachusetts, USA), and MATLAB version 9.1 with the corresponding MATLAB image processing tool (The Mathworks Inc. Natick, Massachusetts, USA). MicroCT data collected with a 16-bit gray level intensity depth is converted to an 8-bit gray level intensity depth, taking care to ensure that the resulting 8-bit data set maintains dynamic range maximum and minimum number of viable saturated voxels, excluding extreme outliers.

[0146] Aligning the sample surface so that it is parallel to the YZ plane of the global geometric axis system is accomplished in one of the following ways, including (a) the use of an accessory for the microCT that aligns the material correctly or ( b) the use of software, such as Avizo, to visually align the surface and use interpolation to resize the dataset.

[0147] The analysis is performed on a processed microCT dataset that contains a square section of material approximately 1.5 mm x 1.5 mm. The dataset goes from edge to edge in the YZ cutting direction. It completely intersects the minimum Y edge, the maximum Y edge, the minimum Z edge, and the maximum Z edge. A small non-material reserve region will exist between the minimum X edge and the maximum X edge. This region will consist of air or packaging material.

[0148] A material threshold is determined by running the Otsu method on all samples of interest and calculating the average of the results. The material threshold should identify the bottle material while minimizing noise and packaging material. Material threshold is applied to the aligned and trimmed dataset. Lines of voxel values, parallel to the x axis, are captured for each Y, Z value of the material dataset. A typical line will consist of a large continuous band of material which is the vial. Smaller bands of material may also be present due to the packaging material used to hold the sample in place or due to noise. The position of the starting and ending voxel of the largest band of material is recorded for each line. These positions are weighted together and provide the edge of the material. The edge of the material may experience microCT diffraction artifacts caused by the sudden change in air density to the polymer. These additional effects can raise edge voxel values enough to be misclassified as pigments. To eliminate this effect, the material boundary, as determined by the average start and end position, is moved inward by 10 voxels.

[0149] With the material limits established, each sample is processed again by the Ostu method to determine a threshold for the pigments. The average of all sample thresholds is used to segment the material's pigment. Each dataset is subjected to a pigment threshold to generate a pigment dataset. Pigment voxels outside the material boundary are set to zero to remove any additional noise and effects.

[0150] The number of pigment voxels in each YZ slice is calculated within the material. Slice totals are added to a grand total. From these summations, the bounding YZ slices are defined as those that enclose 95% of the pigment material. The distances between the material thresholds and the 95% pigment thresholds are reported as the layer thicknesses.

Brightness (GU)

[0151] Gloss is measured at 20°, 60° and 85° geometries using a micro-TRI-gloss meter (BYK-Gardner GmbH) in accordance with ASTM D 2457/D523, ISO 7668/2813 and JIS Z8741. 60° is commonly used to compare samples where samples greater than 70 are measured and recorded at 20°C. For 60°, brightness values of less than 10, 85° geometry is commonly measured and recorded. For the sake of simplicity, all reported measurements are measured at 20°. All brightness measurements are made on a black background which is referred to as "Base Black". Base Black is the black area from the X-Rite grayscale balance card (45as45 L*a*b* 21.077 0.15 -0.29).

Mean square roughness (Rq)

[0152] Suitable regions of the bottle wall are analyzed for Ra (arithmetic mean height) using a portable surface roughness tester such as the Surftest SJ-210 (Mitutoyo America Corporation) being placed at the same height of the bottle. Roughness is measured in units of micrometers. Opacity and reflection methods: Opacity anisotropy, peak specular reflectance (GU) and reflection smoothness (FW at 3/5 of the specular profile height)

[0153] The opacity reported here is also called reflected opacity and is measured with an opacity meter/goniophotometer such as a Rhopoint IQ meter (Glossmeter 20°/60°/85°, DOI meter, opacity meter, goniophotometer, Rhopoint Instruments Limited) in accordance with ASTM E430. Reflected Opacity = 100 x (∑ Pixels 17° to 19° (sample) + ∑ Pixels 21° to 23° (sample))/Specular Gloss (default)

[0154] Opacity Anisotropy is the ratio of the opacity (i.e., reflected opacity) measured by bottle samples when oriented parallel to the height of the bottle to the opacity measured when rotating the sample by 90°.

[0155] Peak Specular Reflectance is measured at 20° with a diode array covering +/- 7.25° of the specular angle in steps of 0.028°. Reflection Smoothness is measured from the Specular Profile (+/- 5.6° of the Specular Angle in Brightness Units) as full width (FW) at 3/5 of the peak height for the peak of the specular profile.

Total luminous transmittance

[0156] Light transmittance is measured using a Ci7800 benchtop sphere spectrophotometer (X-Rite) using D65 illumination. Total luminous transmittance is measured according to the ASTM D1003 method.

Chroma, luminosity and hue (C*, W*, h°)

[0157] The reflected color characteristics of C*, L*, h° are measured using a multi-angle spectrophotometer such as the MA98, available from X-Rite Incorporated, in accordance with method ASTM E 308, ASTM E 1164 , ASTM E 2194, and ISO 7724. Samples are placed on a black background which is referred to as "Base Black". "Base Black" is the black area of the X-Rite grayscale balance card (45as45 L*a*b* 21.077 0.15 - 0.29).

[0158] Samples are measured with CIE Standard Illuminant D65/10° illumination. The measurement naming system used here is written where the first angle given is the illumination angle as defined from the surface normal and the second angle is the specular detection angle. This is further described in Figure 8.

[0159] C*, L* and h° are coordinates of the CIELCH color system where C* = chroma, L* = luminosity and h° = hue angle. Chroma describes the vividness or dullness of a color where higher values correspond to a saturated color appearance and lower values correspond to dull/less saturated colors. Chroma is also known as saturation.

[0160] Luminosity is a measure of the brightness/darkness value where higher values correspond to a brighter appearance and lower values correspond to a darker appearance.

[0161] Hue is an attribute of a color by virtue of which it is discernible as red, green, etc., and which is dependent on its dominant wavelength, and independent of intensity or lightness.

Fixing layer thickness (Interface Layer Thickness):

[0162] Method A: Energy Dispersive X-ray Spectroscopy (EDS) Mapping Method for adjacent layers with unique elemental composition due to resins (e.g. PET/Nylon) or dyes/additives.

[0163] Method A may be used if the vial sample (vial sample preparation is described below) contains dyes and/or additives equal to or greater than 2% by weight, with elemental compositions that can be adequately mapped by EDS (e.g. elements greater than atomic number 3 not including carbon or oxygen). These dyes/additives can be molecular or particulate. If they are particulate in form, they must be well dispersed so that there are about 10 or more particles in a volume of 5 μm x 5 μm x 200 nm. In general, particles should be smaller than 500 nm in the largest dimension.

Sample preparation:

[0164] A piece of the bottle label panel wall, at least 50 mm away from the shoulder/neck or base regions, measuring ~3 cm x 3 cm, is extracted using a heated blade. The heated blade allows cutting of the vial without applying a large amount of force that could induce premature delamination. This is achieved by melting the panel wall material rather than cutting it. The cast edges of the part are removed with scissors; then the ~3 cm x 3 cm piece is cut into several pieces measuring approximately 1 cm x 0.5 cm using a new single sharp blade. The cutting force is applied along the length of the part, parallel to the layers/interfaces, rather than perpendicular to the interface to avoid interface staining.

[0165] Next, the ~1 cm x 0.5 cm pieces are hand polished, edged, producing a polished surface that displays the vial wall cross section and layered structure. Initial polishing consists of using SiC papers, with progressively smaller sand sizes (400, 600, 800 and 1200), while using distilled water as a lubricant/coolant. The 1200 grit polished surface is then further polished using 0.3μm A12O3 polishing medium, with distilled water being used as a lubricant. The samples are then ultrasonically cleaned in a detergent + distilled water solution for 1 minute, followed by three additional cycles of ultrasonic cleaning in fresh distilled water to rinse the detergent from the sample. A final ultrasonic cleaning is performed in ethanol for 2 minutes. The polished and cleaned samples are mounted on a double-sided SEM tip with carbon tape edge up, then coated with approximately 1020 nm of carbon as deposited by a carbon evaporator such as a Leica EM ACE600 instrument (Leica Microsystems) .

Approximate interface identification by SEM:

[0166] Identification of the approximate interface between the A/C or C/B layers is necessary to enable interface discovery in the dual-beam FIB. To identify the approximate interface, SEM imaging and EDS mapping are performed using a modern field emission SEM such as an FEI (Thermo Scientific®) Apreo SEM equipped with a silicon drift EDS detector (SDD) such as an EDAX Octane Elect 30 mm2 SDD (EDAX Inc.). A preliminary EDS map at about 500 to 1000x magnification is collected across the cross-sectional plane to confirm the presence of the layered structure by identifying the unique elements present in each layer. The accelerating voltage is adjusted appropriately to ionize the most ideal electron shell of the elements of interest to generate an x-ray signal. USP Pharmacopeia <1181> (USP29-NF24) provides a useful reference for choosing the best operation to collect the EDS signal.

[0167] The EDS map is used to show the approximate location of the interface between the layers, after which fiducial platinum markers are deposited via electron beam deposition, with the use of a gas injection system (GIS), to mark the location of the interface. Another EDS map is collected with fiducial Pt markers to confirm its location relative to the interface.

Dual Beam FIB Sample Preparation:

[0168] A thin foil sample (100 to 200 nm thick) is required to properly map the interface at high resolution. The coverslip is prepared using a modern double beam FIB such as an FEI (Thermo Scientifc®) Helios 600. The interface is situated on the FIB with the aid of the platinum fiducial markings. The platinum protective cap is then deposited over the area of interest at the interface in the FIB, measuring approximately 30 µm x 2 µm x 2 µm. This is done to protect the material, which will become the coverslip sample, from unnecessary damage from the ion beam. The 30 μm dimension is oriented perpendicular to the interface so that approximately 15 μm covers one side of the interface and 15 μm covers the other side. The material is then removed from each side of the platinum cap, leaving the region as a capped coverslip, measuring approximately 30 µm wide x 2 µm thick x 10 µm deep where the interface is oriented parallel to the 10 µm direction. The coverslip is then extracted, with the aid of an Omniprobe nanomanipulation device (Oxford Instruments), and fixed to an Omniprobe copper grid. The lamellar sample is then diluted, using 30 kV gallium ions, until it is sufficiently thin (~500-200 nm). The newly reduced lamellar sample is then cleaned with 5 kV gallium ions to remove excess damage caused by the 30 kV reduction process.

STEM Data Compilation:

[0169] Transmission scanning electron microscopy (STEM) energy dispersive X-ray spectroscopy (EDS) data is collected using a modern field emission TEM such as an FEI Tecnai TF-20 (Thermo Scientific® ) equipped with a silicon-shifted EDS detector (SDD) such as an EDAX Apollo XLT2 30 mm2 SDD detector (EDAX Inc.) with collection and analysis software such as Apex™ (EDAX Inc.). The interface region from within the sheet produced as described above is mapped with EDS to display the presence and location of elementary constituents in the two polymer layers. The size of the EDS map is about 20 x 10 μm where the interface is perpendicular to the 20 μm direction ("Y" direction) and parallel to the 10 μm direction ("X" direction). The "Y" and "X" directions are perpendicular or nearly perpendicular to each other.

[0170] The map is collected using accelerating voltage between 200 and 300 kV and a beam current at or between 100 and 1 pA to achieve the SDD count rate of at least 3,000 counts per second. The map resolution is at least 256 x 160 pixels with a dwell time of about 200 μs per pixel. Around 200 frames are collected for a total mapping time of around 30 minutes. The elements of interest are selected and an automatic analysis method without standard ZAF as an essential parameter P/W-ZAF is selected to enable quantitative mapping.

Data processing

[0171] EDS map data can be displayed as color-coded images, with a single corresponding color for each element. The color intensity scales with the concentration of the elementary species. The EDS map data is processed to display a normalized atom line profile % by summing the X-ray counts for each element as they occur in the "Y" direction (parallel to the interface) and summing the intensities, are plotted as a function of distance across the interface toward "X" (normal to the interface). The distance between the normalized atom % maximum and minimum value (both having about zero slope over about 2 to 4 microns) for at least one element is defined as the thickness of the interface layer.

[0172] Method B: Confocal Raman Spectroscopy Mapping Method for adjacent layers with unique spectral characteristics due to resins (e.g. PET/COC) or dyes/additives.

[0173] 2D chemical maps or line scans are collected across the interface layer using a confocal Raman microscope (Witec A300R Confocal Raman spectrometer) equipped with a continuous laser beam, motorized sample scanning stage in the x and y directions, video camera with CCD, LED white light source, diode-pumped laser excitations from 488 nm to 785 nm, and 50x to 100x microscope objectives (Zeiss EC Epiplan-Neofluar, NA=0.8 or better).

[0174] Samples are prepared in a similar manner as described in Method A - Sample Preparation section, however the samples are uncoated.

[0175] The sample is mounted on a glass microscope slide with the edge up. An area of interest close to the interface of the layers is located with the help of the video camera's CCD using the white light source. From the area of interest, 2D chemical maps through spectral acquisition are captured by focusing the laser beam at or below the surface and scanning across the layer interface in the X-Y direction with steps of 1 μm or less, with the integration time less than 1 s in each step. The integration time must be adjusted to avoid detector saturation. Raman images are generated using suitable software such as WItec™ software (version 5.0) using spectral features unique to each polymer layer such as peak intensities, integrated areas, peak widths and/or fluorescence. All Raman spectral data at each pixel in the dataset is cosmic ray corrected and reference corrected before image generation. To determine intermixing between polymer layers, a cross-sectional analysis in which the spectral attributes used to generate the chemical map are followed along a line drawn through the interface including at least 10 microns within the area encompassing the polymer layers. polymer of interest. The defined spectral characteristics are plotted against distance in micrometers. The mixing distance of the intermediate layer (i.e., fixation layer) is defined as the distance between the maximum and minimum values of the spectral attributes. Combinations A. A blow molded article comprising a hollow body defined by a wall, the wall having an inner surface and an outer surface, the wall being formed in at least one region by 3 layers, a layer A including the outer surface of the wall in that region, a layer B including the inner surface of the wall in that region and a layer C sandwiched between layers A and B, said article being obtained by blow molding a preform made by means of parallel flow of about of 2 or more chains and one or more chains forming layers A and B and the remaining chains making up layer C, layer C comprising a visible pigment through layer A and there being a fixation layer between the layer A and C, with the layers being slightly interpenetrated. B. The article according to paragraph A, wherein the layer comprises a thickness and layer B comprises a thickness and the thickness of layer A is greater than the thickness of layer B. C. The article according to either paragraph above, the article additionally comprising a front side which is non-flat. D. The article according to any of the preceding paragraphs, wherein layer B is made of the same material as layer A. E. The article according to any of the preceding paragraphs, wherein the article is a container, preferably a bottle. F. The article, in accordance with any of the previous paragraphs, being that a wall in the region where layers A, B and C are present comprises a Normal Critical Load, measured in accordance with the method described herein, greater than 30 N, preferably greater than 50 N. G. The article according to any of the preceding paragraphs, said region formed by the three layers comprising more than about 60%, preferably more than about 80%, more preferably more than about 90% by weight of the article. H. The article according to any of the preceding paragraphs, wherein the pigment in layer C comprises an effect pigment comprising a pearlizing pigment. I. The article according to paragraph H, wherein the effect pigment is about 0.01% to about 5% by weight of the layer C. J. The article according to paragraph H, wherein the pigment effect comprises platelet-type pigments with a face in which the pigments are primarily oriented so that the face is parallel to the external surface of the article. K. The article, in accordance with any of the previous paragraphs, with layer C being produced from more sublayers with at least the sublayer forming the surface of layer C, which faces the corresponding surface of layer A, comprises effect pigments. L. The article, according to any of the previous paragraphs, wherein the wall thickness of the article in the region formed by the 3 layers is from about 0.2 to about 5 mm and wherein, preferably, layer C it has a thickness between about 5 and about 40% of the total thickness. M. The article according to any of the preceding paragraphs, wherein the article comprises from about 50% by weight, preferably more than about 70% by weight, more preferably more than 80% by weight , more preferably even more than 90% by weight of thermoplastic resins selected from a group consisting of polyethylene terephthalate (PET), polyethylene glycol terephthalate (PETG), polystyrene (PS), polycarbonate (PC), polyvinyl chloride ( PVC), polyethylene naphthalate (PEN), polycyclohexylenedimethylene terephthalate (PCT), glycol-modified PCT copolymer (PCTG), cyclohexane dimethanol terephthalic acid copolyester (PCTA), polybutylene terephthalate (PBCT), acrylonitrile styrene (AS), styrene butadiene copolymer (SBC), low density polyethylene (LDPE), linear low density polyethylene (LLPDE), high density polyethylene (HDPE), propylene (PP) and a combination thereof. N. The article, in accordance with any of the previous paragraphs, where the article has a non-cylindrical shape. O. A blow molded article having a hollow body defined by a wall, the wall having an inner surface and an outer surface, the wall being formed in at least one region by 3 layers, a layer A including the outer surface of the wall in this region, a layer B including the internal surface of the wall in this region and a layer C pressed between layers A and B, with the three layers A, B and C together making up the entire wall of the article in the region, with the layer A is transparent and layer C comprises a pigment with visible effect through layer A, and said article in the region where layers A, B and C are present has an importance for the Normal Critical Load, according to the method described here, greater than about 50 N.

[0176] The dimensions and values disclosed herein should not be understood as being strictly limited to the exact numerical values mentioned. Instead, except where otherwise specified, each such dimension is intended to mean both the referenced value and a range of functionally equivalent values around that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

[0177] Each document cited in the present invention, including any patent or patent application cross-referenced or related, and any patent application or patent in which the present application claims priority or benefit thereof, is hereby fully incorporated herein by reference , except where expressly excluded or otherwise limited. Reference to any document is not an admission that it constitutes prior art with respect to any invention disclosed or claimed herein, nor that it, alone or in any combination with any other reference or references, teaches, suggests or reveals such an invention. Furthermore, if there is a conflict between any meaning or definition of a term mentioned in this document and any meaning or definition of the same term in a document incorporated by reference, the meaning or definition given to that term in this document will take precedence.

[0178] Although specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without deviating from the spirit and scope of the invention. It is therefore intended to cover in the attached claims all such changes and modifications that fall within the scope of the present invention.

Claims (14)

1. Blow-molded article (1), characterized in that it comprises a hollow body (25) defined by a wall (3), wherein the wall (3) has an internal surface (5) and an external surface (6), in that the wall (3) is formed in at least one region by 3 layers, a layer A including the outer surface (6) of the wall (3) in that region, a layer B including the inner surface (5) of the wall (3) in this region and a layer C pressed between layers A and B, wherein the article (1) is obtained by blow molding a preform made by means of parallel flow co-injection of 2 or more currents, wherein one or more currents form layers A and B and the remaining currents make up layer C, wherein layer C comprises a pigment visible through layer A, wherein between layers A and C and layers B and C there is a layer transitional in which the layers are interpenetrated; wherein the transition layer between layers A and C and/or layers B and C has a thickness of 500 nm to 125 μm. 2. Article (1) according to claim 1, characterized in that layer A comprises a thickness and layer B comprises a thickness and the thickness of layer A is greater than the thickness of layer B. 3. Article (1), according to claim 1, characterized in that the article (1) additionally comprises a non-planar front side. 4. Article (1) according to claim 1, characterized in that layer C comprises an effect pigment comprising a pearlizing pigment. 5. Article (1) according to claim 4, characterized in that the effect pigment is 0.01% by weight to 5% by weight of layer C. 6. Article (1) according to claim 4, characterized in that the effect pigment comprises platelet-type pigments with a face in which the pigments are oriented mainly so that the face is parallel to the external surface (6) of the article ( 1). 7. Article (1), according to claim 1, characterized in that the article (1) comprises a location on the external surface (6) with an opacity of less than 20. 8. Article (1), according to claim 1, characterized in that the article (1) comprises a location on the external surface (6) with an opacity anisotropy less than or equal to 0.9. 9. Article (1), according to claim 1, characterized in that the article (1) comprises a location on the external surface (6) with a brightness of 20° greater than or equal to 60 GUs. 10. Article (1), according to claim 1, characterized in that the article (1) comprises a location on the external surface (6) with a ΔC* of at least 15. 11. Article (1), according to claim 1, characterized in that the article (1) comprises a location on the external surface (6) with a C* (45 in -15) greater than 35. 12. Article (1), according to claim 1, characterized in that layer A is transparent and layer C is non-transparent. 13. Article (1), according to claim 1, characterized in that the thickness of the transition layer between layers A and C and/or layers B and C is 1 μm to 100 μm. 14. Article (1), according to claim 1, characterized in that the region formed by three layers comprises more than 90% of the weight of the article (1).