White acrylonitrile-butadiene-styrene compositions and related thermoplastic article

Abstract

A thermoplastic article that includes: a copolymer comprising acrylonitrile units, butadiene units and aromatic units; 2-6 wt.% of an ethylene-acrylic acid (EAA) copolymer having a molar ratio of ethylene to acrylic acid of x:y, wherein x is an integer in ranging from 160-800 and y is an integer ranging from 4.8 to 35; and 1-6 wt.% of titanium dioxide, wherein the wt.% is based on the total weight of the thermoplastic article. The thermoplastic article includes a core region and a surface region surrounding the core region. A concentration of the EAA copolymer is higher in the surface region than in the core region and a concentration of the titanium dioxide is higher in the surface region than in the core region.

Description

T&I0039-WO-ORD 1WHITE ACRYLONITRILE-BUTADIENE-STYRENE COMPOSITIONS ANDRELATED THERMOPLASTIC ARTICLETECHNICAL FIELD

[0001] The present disclosure is directed to acrylonitrile-butadiene-styrene (ABS) compositions with improved white color and related thermoplastic articles and methods.BACKGROUND

[0002] Acrylonitrile-butadiene-styrene (ABS) is a lightweight thermoplastic resin known for its good toughness and ease of processing. ABS can be molded into complex shapes and geometries. ABS resin exhibits the synergistic performance of its three co-polymer components, resulting in excellent properties such as high surface hardness, low- temperature impact resistance, dimensional stability, minimal molding shrinkage, and favorable processing characteristics. Due to these attributes, ABS is widely used across various industries, including home appliances, electrical appliance housings, and automotive components. Generally, ABS resin has yellow color, which may be addressed prior to its use in applications where visual appearance and surface aesthetics are important. This yellow coloration is primarily due to the oxidation of double bonds in the butadiene (BD) rubber component of the ABS matrix. Factors such as heat, oxygen, stress, micro-moisture, impurities, and improper processing techniques contribute to this oxidation. Additionally, heat can cause the fracture of carbon-carbon bonds, leading to the formation of side products that result in further yellow coloration.

[0003] CN106987082A discloses a kind of antibiotic plastic suitable for keyboard, belong to plastic products technology field. A kind of antibiotic plastic suitable for keyboard, is mainly made by the raw material of following parts by weight : 40 65 parts of 100 120 parts of ABS matrix resins, 15 25 parts of makrolon, 2 10 parts of ethylene acrylic acid co polymer, 15 parts of polyvinyl alcohol, 2 10 parts of ethylene propylene diene rubber, 48 parts of antibacterial matrices, 10 15 parts of filler, 5 12 parts of dispersant, 0.2 0.6 parts of antioxidant, 0.3 0.7 parts of coupling agent, 0.2 0.6 parts of stabilizer and compatilizer. Antibacterial matrices are used in the keyboard case material of the present invention, broad-spectrum antibacterial property, antimicrobial sustained-T&I0039-WO-ORD 2 release and the weatherability of plastics is improved, improves the mechanical property of antibiotic plastic.

[0004] CN111688045A relates to the technical field of plastic plate preparation, and particularly provides a hollow plastic cushion plate and a preparation method and application thereof. The invention provides a hollow plastic cushion plate in a first aspect, which comprises a cushion plate body; the base plate body is at least longitudinally provided with a row of through holes which are arranged at equal intervals and penetrate through the base plate body; the thickness of the base plate body is 8-20 mm; the width of the base plate body is 140-220 mm; the distance between the through hole and the leather on the upper surface and the lower surface of the base plate body is 0.5-5 mm; the rib thickness between the through holes is 1-10 mm; the total area of the through holes accounts for 10-70% of the cross section area of the whole base plate body.

[0005] CN110615964A discloses a special plastic plate capable of improving a diamond wire cutting large system and a preparation method thereof, belonging to the technical field of plastic plate preparation, wherein the special plastic plate comprises the following raw materials in percentage by mass: 65-90% of ABS resin, 5-30% of PMMA resin, 1-10% of compatilizer, 1-10% of EAA resin, 0.6-1.5% of scale inhibitor, 0.2-1% of antioxidant, 0.3-2% oflubricant and 0.1-1% of surfactant, wherein the special plastic plate is prepared by the steps of mixing raw materials, granulating, extruding, molding, grinding, cutting, detecting, packaging and the like. The special plastic plate can effectively adjust the pH value and the conductivity of a large circulation system, has the characteristic of facilitating the recovery and the cyclic utilization of silicon materials and ABS / PMMA plastic plates, and can bring obvious benefits of saving energy consumption, reducing cost and improving production efficiency.

[0006] CN 117964993A relates to an ABS resin reinforcing additive, an ABS resin material and a preparation method thereof, wherein the preparation method of the ABS resin reinforcing additive comprises the following steps: dispersing nano titanium dioxide into deionized water to obtain nano titanium dioxide dispersion liquid; adding a surfactant into the nano titanium dioxide dispersion liquid, uniformly mixing, adding carbon nano tubes, uniformly mixing, filtering, washing and drying to obtain a composite material A; adding the composite material A and nano titanium dioxide into23T&I0039-WO-ORD 3 a Tris solution of dopamine, uniformly mixing, filtering, washing and drying to obtain a composite material B; and (3) carrying out heat treatment on the composite material B to obtain the ABS resin reinforcing additive. The ABS resin reinforced additive prepared by the invention has a multi-layer structure, high light refraction and high light activity, and strong ultraviolet resistance, and the ABS resin reinforced additive can be added into ABS resin to ensure that the ABS resin material has stronger blocking capability to ultraviolet rays, and can greatly improve the ultraviolet aging resistance of the ABS resin material.SUMMARY

[0007] This disclosure describes technologies relating to ABS compositions with improved white color and the method of preparing the same. In various implementations, the disclosure provides ABS compositions with improved whiteness by using two additives: a polar copolymer and inorganic solid particles. For example, ethylene acrylic acid (EAA) copolymer and titanium dioxide (TiCh) can be used for the additives. The specific ABS compositions described in the disclosure can exhibit improved whiteness without using any further additives such as metallic pigments, pearlescent pigments or sheet glass. Further, in general, the two additives do not negatively impact the thermal and mechanical properties. The interplay of the two additives can have a synergetic effect to improve the characteristics of the formed polymer structure. In some implementations, the polar copolymer in the polymer melt matrix can migrate toward the surface of an extrudate or mold structure during the processing. This migration can help concentrate the solid particles near the surface, thereby improving the whiteness with a reduced amount of the solid particles.

[0008] An implementation described herein provides a thermoplastic article including: a copolymer comprising acrylonitrile units, butadiene units and aromatic units; 2-6 wt.% of an ethylene-acrylic acid (EAA) copolymer having repeating units of the formula.wherein x is an integer in ranging from 160-800 and y is an integer ranging from 4.8 to 35; and 1 -6 wt. % of titanium dioxide, wherein the wt. % is based on the total weight of the thermoplastic23T&I0039-WO-ORD 4 article. The thermoplastic article includes a core region and a surface region surrounding the core region. A concentration of the EAA copolymer is higher in the surface region than in the core region, and a concentration of the titanium dioxide is higher in the surface region than in the core region.

[0009] An implementation described herein also provides a process for preparing the thermoplastic article as described in this disclosure. The process includes: forming a melt by mixing the copolymer, the EAA copolymer, and the titanium dioxide at a temperature from 180 °C to 300°C; and extruding the melt to form the thermoplastic article, wherein at least a portion of the EAA copolymer and the titanium dioxide migrates to the surface region during or after the extruding.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] For a more complete understanding of the implementations described herein, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying figures, in which:

[0011] FIG. 1 is a schematic representation of an ABS composition including an ABS copolymer, a polar copolymer, and inorganic solid particles;

[0012] FIG. 2 is a perspective view of an extrudate of the ABS composition;

[0013] FIG. 3 shows bar charts for comparison of color properties of four ABS samples;

[0014] FIG. 4 shows transmission electron microscopy (TEM) micrographs of ABS samples without (A) and with (B) the polar copolymer; and

[0015] FIG. 5 shows transmission electron microscopy (TEM) micrographs of ABS-TiCh samples without (C) and with (D) the polar copolymer.DETAILED DESCRIPTION

[0016] In various implementations of the present disclosure, the whiteness of ABS is improved by the use of two additives: a polar copolymer and inorganic solid particles. Generally, as-synthesized ABS can have a yellow color. Mechanical processing and exposure to sunlight or other illumination can cause further coloration through chemistry such as oxidation. For applications where white visual appearance and surface aesthetics are desired, for example, indoor wall layers for a refrigerator, the relatively poor base color and long-term stability may be addressed by modification to the ABS composition.T&I0039-WO-ORD 5

[0017] FIG. 1 is a schematic representation of an ABS composition in accordance with various implementations, showing the chemical structure of an ABS copolymer 100 as the main component, the chemical structure of an EAA copolymer 102, and inorganic solid particles 104. In some implementations, the acrylonitrile units account for 10-45 wt.%, for example, 15-35 wt.% or 20-25 wt.%, of the total weight of the ABS copolymer 100. In some implementations, the acrylonitrile units account for about 22 wt.% of the ABS copolymer 100.

[0018] In some implementations, the BD units account for 1-50 wt.%, for example, 5-40 wt.%, 10-30 wt.%, or 15-20 wt.%, of the total weight of the ABS copolymer 100. In some implementations, the BD unites account for about 18 wt.% of the ABS copolymer 100.

[0019] In some implementations, the styrene units account for 30-75 wt.%, for example, 40-70 wt.%, or 50-65 wt.%, of the total weight of the ABS copolymer 100. In some implementations, the styrene units account for about 60 wt.% of the ABS copolymer 100. In some implementations, the ABS copolymer 100 has a composition of about 22 wt.% acrylonitrile units, about 18 wt.% BD units, and about 60 wt.% styrene units.

[0020] In various implementations, the ABS copolymer 100 has a molecular weight from 50,000-300,000 g / mol.

[0021] The ABS composition can include more than one ABS copolymer composition. In various implementations, the ABS copolymer 100 accounts for 88-97 wt.% of the total weight of the ABS composition. In various implementations, the main component of the ABS composition includes a mixture of the ABS copolymer 100 and one or more polymers that contains acrylonitrile, butadiene, styrene, or any combination of the three with or without other monomer units. In some implementations, the ABS composition includes a mixture of a styrene acrylonitrile (SAN) copolymer and another polymer such as BD rubber. For example, the SAN copolymer can contain from about 15 wt.% to about 35 wt.% acrylonitrile units. In some implementations, the acrylonitrile units account for from about 20 wt.% to about 30 wt.%, from about 20 wt.% to about 25 wt.%, or from about 25 wt.% to about 30 wt.% of the SAN copolymer. The SAN copolymer can contain from about 70 wt.% to about 95 wt.% styrene units. In some implementations, the styrene units account for from about 75 wt.% to about 90 wt.%, or from about 80 wt.% to about 85 wt.% of the SAN copolymer. In some implementations, a BD rubber to be mixed with the SAN copolymer contains, in addition to BD, acrylonitrile, styrene, and methyl methacrylate (MMA) units. ForT&I0039-WO-ORD 6 example, the BD rubber can contain from about 5 wt.% to about 15 wt.%, for example, from about 8 wt.% to about 10 wt.% acrylonitrile units. In some implementations, the BD rubber contains from about 50 wt.% to about 70 wt.%, for example, from about 55 wt.% to about 65 wt.% or from about 59 wt.% to 63 wt.% BD units. In some implementations, the BD rubber contains from about 20 wt.% to about 35 wt.%, for example, from about 25 wt.% to about 30 wt.% or from about 26 wt.% to 29 wt.% styrene units. In some implementations, the BD rubber contains from about 1 wt.% to about 5 wt.%, for example, from about 2 wt.% to about 3 wt.% MMA units.

[0022] While this disclosure primarily describes ABS compositions with the ABS copolymer as the main component, the addition of two additives to a different main polymer component is possible. For example, the copolymer including acrylonitrile units, BD units, and aromatic units different from styrene units can also be used to prepare a thermoplastic composition with the two additives described in this disclosure. Accordingly, the non-ABS thermoplastic are also within the scope of this disclosure. The polymer composition can also include one or more main components. In some implementations, at least one of the main components is the ABS copolymer. In some implementations, the compositions do not include polycarbonate or polymethyl methacrylate (PMMA). In a preferred implementation, the composition contains only ABS.

[0023] The first additive can include the EAA copolymer 102. In various implementations of the EAA copolymer 102, x is an integer in ranging from 160-800 and y is an integer ranging from 4.8 to 35 for the EAA copolymer. In some implementations, the EAA copolymer 102 has a molecular weight from 500-10,000 g / mol. The molecular weight of the EAA copolymer 102 can be selected to be lower than that of the ABS copolymer 100. The lower degree of polymerization of the EAA copolymer 102 can assist its migration in the polymer matrix. In some implementations, the ABS: EAA molecular weight ratio is from about 5: 1 to 600: 1, for example, about 10: 1, about 50: 1, about 100: 1, about 200: 1, or about 300: 1. In some implementations, the molecular weight ratio of the two copolymers can be selected to optimize the effect of migration on the color properties of the resulting ABS composition. The EAA copolymer 102 can account for 2-10 wt.%, for example, 4-10 wt.%, 6-10 wt.%, 8-10 wt.%, 2-8 wt.%, 2-6 wt.%, or 2-2 wt.%, of the total weight of the ABS composition. In some implementations, the acrylic acid units account for 1-10 wt.%, for example 3-10 wt.%,T&I0039-WO-ORD 75-10 wt.%, 7-10 wt.%, 1-7 wt.%, 3-7 wt.%, or 5-7 wt.%, of the total weight of the EAA copolymer 102.

[0024] In some implementations, the first additive can include a different polar polymer in addition to or in place of the EAA copolymer 102. For example, polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), or olefm-acrylic acid copolymers can be used.

[0025] The second additive can include the inorganic solid particles 104. The inorganic solid particles 104 can include an oxide material such as metal oxide that can improve the whiteness or reduce the yellowness of the ABS composition. In various implementations, the inorganic solid particles 104 include titanium dioxide. As used herein, “titanium dioxide” is not limited to strictly stoichiometric TiCh, but includes TiOx, where x is from about 1.8 to about 2.2.

[0026] In various implementations, the inorganic solid particles 104 can include a crystalline material. In some implementations, the inorganic solid particles 104 can include rutile TiCh, anatase TiCh, or their combination. The inorganic solid particles 104 can account for 1-6 wt.%, for example, 2-6 wt.%, 3-6 wt.%, 4-6 wt.%, 5-6 wt.%, 1-5 wt.%, 1-4 wt.%, 1-3 wt.%, or 1-2 wt.%, of the total weight of the ABS composition. Further, the inorganic solid particles 104 can be characterized with an average particle size suitable for blending in the ABS composition. For example, the inorganic solid particles 104 can have an average particle size of 0.01-3 micrometers, determined by an electron microscope.

[0027] The ratio of each component for the ABS composition can be selected to optimize the balance of the resulting color property and other materials properties such as mechanical and thermal properties. In some implementations, the ABS composition contains 3-10 wt.% of the EAA copolymer 102 and 1-3 wt.% of the inorganic solid particles 104 based on the total weight of the ABS composition. In some implementations, the ABS composition contains 2-6 wt.% of the EAA copolymer 102 and 1-6 wt.% of the inorganic solid particles 104 based on the total weight of the ABS composition.

[0028] In various implementations, the ABS composition is substantially free of any other types of coloring additives such as metallic pigments, pearlescent pigments and sheet glass. For example, the concentration of such coloring additives excluding the inorganic solid particles 104 can be less than 0.1 wt.%, or less than 0.01 wt.%, or less than 0.001 wt.%.T&I0039-WO-ORD 8

[0029] The ABS composition can be shaped into a thermoplastic article, for example, is a sheet extruded article. As used herein, a thermoplastic article refers to an article primarily composed of a polymer that reversibly becomes pliable or moldable at an elevated temperature and solidifies upon cooling. In some implementations, the thermoplastic article has a melting temperature from about 110 °C to about 300°C. The ABS composition can have a melting temperature from about 190 °C to about 270°C in some implementation. The solidification of the polymer melt can be performed by cooling the material to a temperature well below the melting temperature, for example, from about 40 °C to about 80°C.

[0030] As an initial step of making the thermoplastic article, the melted polymer mixture containing the additives can be prepared by physically mixing the components, for example, the ABS copolymer 100, the EAA copolymer 102, and the inorganic solid particles 104, and heating the mixture. Molding of the melted polymer mixture into a target shape can be performed using techniques such as injection molding, blow molding, sheet extrusion, profile extrusion, wire drawing, or any combination of them. In some implementations, the method of preparing the thermoplastic article includes forming a melt by mixing the components at a temperature from about 180 °C to about 300°C, for example, from about 200 °C to about 300°C, from about 220 °C to about 300°C, from about 240 °C to about 300°C, from about 260 °C to about 300°C, from about 280 °C to about 300°C, from about 180 °C to about 280°C, from about 180 °C to about 260°C, from about 180 °C to about 240°C, from about 180 °C to about 220°C, or from about 180 °C to about 200°C. The method can then proceed to extruding the melt to form the thermoplastic article. The additives in the ABS composition, at least partly due to the polar nature of the additives such as the EAA copolymer 102, can migrate towards the surface of the molded structure or extrudate during or after the shaping process. In various implementations, this migration results in an additive concentration gradient in the thermoplastic article, thereby making the whiteness improvement or yellowness reduction can be more prominent at or near the surface. Since the color of an outer surface can be most relevant to determining the appearance of an opaque object, concentrating the color-adjusting additives towards the surface can help maximizing the coloring effect of the additives.

[0031] In FIG. 2, an extrudate 200 of the ABS composition has a surface region 202 and a core region 204 visible in a cross section. In various implementations, the concentrations of the EAA copolymer and the inorganic solid particles in the extrudate23T&I0039-WO-ORD 9200 are higher in the surface region 202 than in the core region 204 due to the migration of these components. In some implementations, their concentrations are higher at the exposed surface of the extrude 200 than in the core region 204. The regional concentrations of components can be determined as average values, for example, determined by elemental analysis across the cross section. For example, energy dispersive X-ray spectroscopy (EDX) analysis can be used in combination with electron microscopic imaging. The surface region 202 can refer to a sub-surface area of the extrudate 200 covering an area from the surface to a maximum depth of 1%, 5%, 10%, 20%, or 30% of the width (W) or height (H) of the cross section in FIG. 2.

[0032] The contrast illustrated for the two regions in FIG. 2 is simplified to highlight the concentration difference between them, and not suggesting the absence of any component in the core region 204. In some implementations, a majority (over 50 wt.%) of the two additives migrate to the surface region 202. In some implementations, at least about 60 wt.% of the two additives are present in the surface region 202. The degree of migration of the two additives can depend on various process parameters of the molding or extruding process, for example, injection speed, retention time, and molding temperature.

[0033] Such preferential migration of the additives can reduce the yellowness index (YI) and improve the gloss, while the inorganic solid particle 104 can improve the photo stability of the ABS composition. In various implementations, for the ABS composition, a YI according to ASTM E313-20 is less than 20, for example less than 16. A lightness L* in the CIELAB color space, defined by the International Commission on Illumination (CIE), can be at least 91.EXAMPLES

[0034] The following examples serve to further illustrate various implementations and applications. In the Examples below, a series of samples with varying ABS compositions was prepared and characterized for their color properties and morphology.

[0035] The series of four samples were prepared in 5 kg scale with varying compositions summarized in Table 1. Sample 1 is a reference ABS composition. The primary ABS copolymer fraction is prepared using the two main precursors: styrene-acrylonitrile copolymer (SAN copolymer) pellets coded as SAN 576 and BD rubber coded as HRGT&I0039-WO-ORD 10362. The BD rubber further contains acrylonitrile, styrene, and MMA units. SAN 576 contains 23-32 wt.% acrylonitrile units and 77-86 w.t% styrene units. HRG 362 contains 7-12 wt.% acrylonitrile units, 57-65 wt.% butadiene units, 23-32 wt.% styrene units, and 1-4 wt. % MMA units. All samples further contain additives: magnesium oxide (MgO) as an acid scavenger, and ethylene bis stearamide wax (Kemamide® EBS wax obtained from PMC Biogenix, Inc.).

[0036] Samples 2-4 were prepared with the addition of the EAA copolymer (Nucrel™ 30707 Acid Copolymer obtained from Dow Inc.), TiCh, or both as further summarized in Table 1. The EAA concentration was about 3 wt.% and the TiCh concentration was about 2 wt.%. The EAA copolymer contains 6.9 wt.% of acrylic acid. While the SAN 576 pellets, the EAA copolymer and TiCh were added through the main hopper / feeder, the pre-blend of BD rubber (HRG 362) along with processing additives including EBX wax, magnesium stearate, MgO and silicone fluid was fed through the side feeder connected to a secondary barrel. The precursors were mixed together in a plastic container to obtain a homogeneous mixture of the pellets and powders.Table 1 ABS compositionsSample 4Sample 1 Sample 2 Sample 3ABS-ABS ABS / EAA ABS / TiO2EAA / TiO2SAN copolymer (g) 1435 1435 1435 1435ABSBD rubber (g) 3565 3565 3565 3565MgO (g) 5 5 5 5EBS wax (g) 25 25 25 25EAA (g) - 150 - 150TiO2(g) - - 100 100Total (g) 5030 5180 5130 5280

[0037] The mixture was melt blended in a 10-barrel Coperion ZSK-24 mm co-rotating twin-screw extruder whose length-to-diameter (L / D) ratio is 40: 1. Extrusion of the mixture was performed while adjusting the material throughput to maintain the torque at 80% and the screw rotation rate was kept at 150 rpm. The feeder and cutter were operated at 40 rpm and 2 rpm, respectively. The melt pressure was 13 bar (1.3 MPa). The material throughput was constant at about 5 kg / h for the series of samples. TheT&I0039-WO-ORD 11 barrels of the extruder were kept at following temperatures from 1stto 10thbarrel: 200 °C, 220 °C, 230 °C, 240 °C, 250 °C, 250 °C, 255 °C, 260 °C, 260 °C, and 260 °C.

[0038] The ABS samples were characterized for their thermal and mechanical properties and their results are summarized in Table 2. The results demonstrate little to no impact on these properties by the additives. The Izod Impact (Nil) slightly increased after adding the EAA copolymer into the ABS, but it was lowered with the addition of TiCh. The addition of both additives resulted in the highest Nil at 22.38 MPa. On the other hand, the Vicat softening temperature and heat deflection temperature remained mostly unchanged in all the compositions. The tensile strength slightly dropped in ABS- EAA / TiCh. The flexural modulus shows a drop of 11% in ABS-EAA / TiCh compared to the ABS (Sample 1), which can be beneficial in improving the overall processability of final composition.Table 2 Mechanical and thermal properties of ABS samplesSample 1 Sample 2 Sample 3 Sample 4ABS ABS / EAA ABS / TiO2ABS-EAA / TiO2Izod impact20.49 22.04 18.02 22.38(MPa)Vicat softening97.97 97.07 97.90 97.97 temperature (°C)Heat deflection87.27 86.73 87.50 87.00 temperature (°C)Tensile strength32.28 32.06 32.16 30.92(MPa)Flexural Modulus 2561 2454 2348 2777(MPa)

[0039] For color comparison, the samples were injection molded into plaques. Qualitatively, the order of whiteness of samples was Sample 4 > Sample 3 > Sample 2 > Sample 1. The difference between Samples 1 and 2 were rather small, the clear enhancement in whiteness was observed from Sample 2 to 3, with an additional improvement was found in Sample 4.

[0040] The color improvement was then quantified by YI measurements as per ASTM E313-20 using spectrophotometry. The YI measurements can quantify a sample's color change from clear or white to yellow. The results were summarized in Table 3 and FIG.T&I0039-WO-ORD 123. The YI of Sample 2 (ABS / EAA) is about 2 units lower than that of Sample 1 (ABS). A further lowering of YI by about 8 units is evident for Samples 3 and 4, demonstrating the synergetic effect of the combined use of the EAA copolymer and TiCh on the reduction of the yellowness.

[0041] Further, the colors and lightness of the samples were quantified using parameters of CIELAB color space. The letters L*, a* and b* represent each of the three values in the CIELAB color space used to measure objective color and calculate color differences. L* represents lightness from black to white on a scale of zero to 100, while a* and b* represent chromaticity with no specific numeric limits. Negative a* corresponds with green, positive a* corresponds with red, negative b* corresponds with blue and positive b* corresponds with yellow. As shown in Table 3 and FIG. 3, a slight increase in L* by about 1.4 units was found from Sample 1 to Sample 2. L* further increased by about 4 units and about 0.8 units from Sample 2 to 3, and then Sample 3 to 4, respectively, demonstrating a substantial whiteness improvement. The gradual improvement in the L* again shows a synergetic effect between the EAA copolymer and TiCh. As shown in Table 3, the standard deviationTable 3 Measurement of yellow index (YI) and lightnessSample 1 Sample 2 Sample 3 Sample 4ABS ABS / EAA ABS / TiO2ABS-EAA / TiO2YI 23.42 ± 0.03 21.88 ± 0.03 16.87 ± 0.03 15.67 ± 0.02L* 84.62 ± 0.01 86.21 ± 0.01 90.33 ± 0.01 91.30 ± 0.01 a* -0.58 ± 0.017 -0.60 ± 0.010 -0.04 -0.36 b* 12.02 ± 0.010 11.38 ± 0.012 8.79 ± 0.015 8.40 ± 0.012

[0042] The morphology of the ABS samples was further characterized using a Tecnai T12 TEM operated at 120 kV and TEM micrographs are shown in FIGS. 4 (Samples 1 and 2) and 5 (Samples 3 and 4). In particular, to analyze the spatial arrangement of different components, TEM imaging was performed at the surface and core regions of the samples.

[0043] To improve the contrast of species of ABS samples in the TEM analysis, Samples 1 and 2 were stained with Osmium (Os) stain prior to the imaging. The BD rubbers stain dark with Os while the EAA remain unstained, enhancing the contrast in the TEM micrographs. The unstained domains in the images can be attributed to the EAA copolymer. On the other hand, the contrast from the inorganic TiCh particles can be23T&I0039-WO-ORD 13 seen best in the TEM micrographs without staining. Staining a TiCh-containig sample may confound the inorganic particles with the stained BD rubbers. Accordingly, Samples 3 and 4 were not stained. The staining process was performed by dipping the pieces of the samples in 4% Osmium tetroxide solution for 2 h, followed by cryomicrotomy at -40 °C. Thin slice specimen with 100-200 nm thickness were collected and characterized by TEM.

[0044] In FIG. 4, the top panel shows the TEM micrographs of Sample 1 at the surface (left) and core region (right). The surface image shows 5-8 um thick skin region with disordered and sheared BD rubbers in the ABS matrix, indicating the non-uniformity of the composition within the sample. The core region has rounded bi-modal sized BD, where large particles with sizes in the range of about 500 nm to about 1 pm diameter and smaller particles with sizes in the range of about 50 nm to about 150 nm diameter were found. The bottom panel of FIG. 4 shows the TEM micrographs of Sample 2 (ABS / EAA). The surface region (left) shows larger amounts of EAA as compared to the core region (right), demonstrating the uneven distribution of the EAA within the sample. The BD particles at the surface region are highly sheared as compared to the core region.

[0045] In FIG. 5, the top panel shows the TEM micrographs of Sample 3 (ABS / TiCh). In both regions, the TiCh particles and agglomerates are evenly dispersed, while the slightly improved dispersion at the surface is demonstrated by the higher particle population (152 particles) as compared to the core region (76 particles). The particle and aggregate sizes vary from about 30 nm to about 1 pm. The bottom panel of FIG. 5 shows the TEM micrographs of Sample 4 (ABS-EAA / TiCh). The TiCh particles are confined to the EAA domains, which are larger at the surface compared to the core region. The particle and aggregate sizes range from about 30 nm to about 500 nm, indicating the suppressed aggregation by the addition of the EAA copolymer.Implementations

[0046] An implementation described herein provides a thermoplastic article comprising: a copolymer comprising acrylonitrile units, butadiene units and aromatic units; 2-6 wt.% of an ethylene-acrylic acid (EAA) copolymer having repeating units of the formula23T&I0039-WO-ORD 14

[0047] wherein x is an integer in ranging from 160-800 and y is an integer ranging from4.8 to 35; and 1-6 wt.% of titanium dioxide, wherein the wt.% is based on the total weight of the thermoplastic article.

[0048] An implementation described herein provides a thermoplastic article that includes: a copolymer comprising acrylonitrile units, butadiene units and aromatic units; 2-6 wt.% of an ethylene-acrylic acid (EAA) copolymer having repeating units of the formula

[0049] wherein x is an integer in ranging from 160-800 and y is an integer ranging from 4.8 to 35; and 1-6 wt.% of titanium dioxide, wherein the wt.% is based on the total weight of the thermoplastic article. The thermoplastic article includes a core region and a surface region surrounding the core region. A concentration of the EAA copolymer is higher in the surface region than in the core region and a concentration of the titanium dioxide is higher in the surface region than in the core region.

[0050] In an aspect, combinable with any other aspect, a yellowness index (YI) of the thermoplastic article according to ASTM E313-20 is less than 16.

[0051] In an aspect, combinable with any other aspect, a lightness L* of the thermoplastic article is at least 91.

[0052] In an aspect, combinable with any other aspect, the aromatic units include styrene units.

[0053] In an aspect, combinable with any other aspect, the copolymer is an acrylonitrile- butadiene-styrene (ABS) copolymer, and the aromatic units are styrene units.

[0054] In an aspect, the ABS copolymer includes from 10-45 wt.% of the acrylonitrile units, based on the total weight of the ABS copolymer.

[0055] In an aspect, the ABS copolymer includes from 1-50 wt.% of the butadiene units, based on the total weight of the ABS copolymer.23T&I0039-WO-ORD 15

[0056] In an aspect, the ABS copolymer includes from 30-75 wt.% of the styrene units, based on the total weight of the ABS copolymer.

[0057] In an aspect, combinable with any other aspect, the EAA copolymer has a molecular weight from 500-10,000 g / mol.

[0058] In an aspect, combinable with any other aspect, the titanium dioxide has a crystalline form of rutile type or anatase type.

[0059] In an aspect, combinable with any other aspect, the titanium dioxide has an average particle size of 0.01-3 micrometers, determined by an electron microscope.

[0060] In an aspect, combinable with any other aspect, the thermoplastic article is substantially free of metallic pigments, pearlescent pigments and sheet glass.

[0061] In an aspect, combinable with any other aspect, the thermoplastic article is a sheet extruded article.

[0062] An implementation described herein also provides an automotive part, an electronic / electrical component, or a home appliance part including the thermoplastic article described in this disclosure.

[0063] An implementation described herein also provides a process for preparing the thermoplastic article of any of claims 1-13, the process comprising: forming a melt by mixing the copolymer, the EAA copolymer, and the titanium dioxide at a temperature from 180 °C to 300°C; and extruding the melt to form the thermoplastic article.

[0064] An implementation described herein also provides a process for preparing the thermoplastic article described in this disclosure. The process includes: forming a melt by mixing the copolymer, the EAA copolymer, and the titanium dioxide at a temperature from 180 °C to 300°C; and extruding the melt to form the thermoplastic article, wherein at least a portion of the EAA copolymer and the titanium dioxide migrates to the surface region during or after the extruding.

Claims

23T&I0039-WO-ORD 16CLAIMS1. A thermoplastic article comprising: a copolymer comprising acrylonitrile units, butadiene units and aromatic units;2-6 wt.% of an ethylene-acrylic acid (EAA) copolymer having repeating units of the formulawherein x is an integer in ranging from 160-800 and y is an integer ranging from 4.8 to 35; and1-6 wt.% of titanium dioxide, wherein the wt.% is based on the total weight of the thermoplastic article.

2. A thermoplastic article of claim- 1 comprising: a copolymer comprising acrylonitrile units, butadiene units and aromatic units;2-6 wt.% of an ethylene-acrylic acid (EAA) copolymer having repeating units of the formulawherein x is an integer in ranging from 160-800 and y is an integer ranging from 4.8 to 35; and1-6 wt.% of titanium dioxide, wherein the wt.% is based on the total weight of the thermoplastic article, the thermoplastic article comprises a core region and a surface region surrounding the core region,23T&I0039-WO-ORD 17 a concentration of the EAA copolymer is higher in the surface region than in the core region, and a concentration of the titanium dioxide is higher in the surface region than in the core region.

3. The thermoplastic article of claim 1 or 2, wherein a yellowness index (YI) of the thermoplastic article according to ASTM E313-20 is less than 16.

4. The thermoplastic article of any of the claims 1-3, wherein a lightness L* of the thermoplastic article is at least 91.

5. The thermoplastic article of any of claims 1-4, wherein the copolymer is an acrylonitrile-butadiene-styrene (ABS) copolymer, and the aromatic units are styrene units.

6. The thermoplastic article of claim 5, wherein the ABS copolymer comprises from 10- 45 wt.% of the acrylonitrile units, based on the total weight of the ABS copolymer.

7. The thermoplastic article of claim 5 or 6, wherein the ABS copolymer comprises from 1-50 wt.% of the butadiene units, based on the total weight of the ABS copolymer.

8. The thermoplastic article of any of claims 5-7, wherein the ABS copolymer comprises from 30-75 wt.% of the styrene units, based on the total weight of the ABS copolymer.

9. The thermoplastic article of any of claims 1-8, wherein the EAA copolymer has a molecular weight from 500-10,000 g / mol.

10. The thermoplastic article of any of claims 1-9, wherein the titanium dioxide has an average particle size of 0.01-3 micrometers, determined by an electron microscope.

11. The thermoplastic article of any of claims 1-10, wherein the thermoplastic article is substantially free of metallic pigments, pearlescent pigments and sheet glass.

12. The thermoplastic article of any of claims 1-11, wherein the thermoplastic article is a sheet extruded article.

13. An automotive part, an electronic / electrical component, or a home appliance part comprising the thermoplastic article of any of claims 1-12.

14. A process for preparing the thermoplastic article of any of claims 1-13, the process comprising:23T&I0039-WO-ORD 18 forming a melt by mixing the copolymer, the EAA copolymer, and the titanium dioxide at a temperature from 180 °C to 300°C; and extruding the melt to form the thermoplastic article.

15. A process for preparing the thermoplastic article of any of claims 1-14, the process comprising: forming a melt by mixing the copolymer, the EAA copolymer, and the titanium dioxide at a temperature from 180 °C to 300°C; and extruding the melt to form the thermoplastic article, wherein at least a portion of theEAA copolymer and the titanium dioxide migrates to the surface region during or after the extruding .

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