HIGHLY EFFECTIVE POLYMERIC COMPOSITIONS AND IMPACT MODIFIERS

Abstract

The invention relates to the composition of core-shell impact modifiers, in particular those with a high Tg core, a low Tg inner shell, and a high Tg outer shell, synthesized to exhibit a unique concentric morphology and / or a combination of high rubber loading and low particle size and / or require only a low level of surfactants. The incorporation of these impact modifiers into polymer compositions enables a novel combination of properties: high impact while maintaining high gloss, or high impact while maintaining low opacity in the presence of water at elevated temperatures. These impact modifiers also allow for excellent usability, enabling the achievement of excellent impact with a low loading.

Description

The invention relates to a core-shell impact modifier composition, in particular those with a raised core, a thin inner shell, and a raised outer shell, synthesized to exhibit a unique concentric morphology and / or a combination of high rubber loading and low particle size and / or require only a low level of surfactants. The incorporation of these impact modifiers into polymer compositions enables a novel combination of properties: high impact while maintaining high gloss, or high impact while maintaining low opacity in the presence of water at elevated temperatures. These impact modifiers also allow for excellent usability, enabling high impact with low loading. BACKGROUND OF THE INVENTION Polymeric articles are often required to possess a combination of properties such as excellent impact resistance, excellent aesthetics (such as transparency or high gloss for opaque articles), and strong resistance to opacity even in high-temperature and high-humidity environments (commonly referred to as “low-water-content opacity”). For many polymeric materials, the use of low-glass-transition-temperature (Tg) rubber particles to enhance the impact performance of the polymer composition is well established in the industry.In particular, the use of spherical multilayer polymeric particles consisting of a core or inner shell of low-Tg rubber polymers and an outer shell of a high-Tg polymer compatible with the host matrix, termed “core-shell” impact modifiers, has been used for several decades for the hardening of polymers such as PVC, PLA, PC, acrylics, epoxies, and polyesters. (US3843753, USUS3661994) For certain acrylic polymers, such as polymethyl methacrylate (PMMA), the use of a high-Tg core, a low-Tg rubber inner shell, and a high-Tg outer shell has been shown to be advantageous for achieving the optimum level of impact performance. (US443103, US4521568, US5270397) Unfortunately, the use of core-shell impact modifier particles in polymer compositions, while improving impact performance, has limitations regarding the extent to which a brittle polymer matrix such as PMMA can be hardened. US7294399B2 demonstrated that significantly improved impact performance can be achieved in a ML / t / ZUZ I / UUZ l Ί O acrylic formulation by adding a lower Tga alkyl acrylate comonomer to the matrix along with the use of a high rubber filler in the core. However, the use of the alkyl acrylate copolymer in the matrix is ​​detrimental to the thermal properties of the composition, such as the heat distortion temperature (HDT). Furthermore, unfortunately, the use of core-shell impact modifier particles in polymer compositions has also been shown to improve impact performance, but can be detrimental to properties such as gloss, temperature opacity (opacity that occurs in a transparent article when the temperature rises above room temperature), and water opacity resistance. In US2017 / 0298217 A1 and WO2014 / 54543, the use of small-sized particles was shown to improve water opacity resistance, but the improvements in impact properties were modest, and no improvements in water opacity resistance were demonstrated. It is highly desirable to develop a core-shell impact modifier that enables excellent impact properties in brittle matrices such as PMMA while maintaining very good aesthetics (high transparency or gloss), low-temperature opacity, and high resistance to water opacity. It is also desirable to develop a highly effective impact modifier that can be used with low loads but still provides significant improvements in impact performance. Surprisingly, it has been discovered that by developing core-shell impact modifier particles with small particle size and high rubber content, excellent impact performance can be achieved while maintaining excellent aesthetics. It has also been found that developing highly concentric core-shell particles improves impact properties, particularly for small particle sizes. Finally, it was discovered that limiting the use of surfactant in the synthesis of impact modifier particles, particularly for small particle sizes, can achieve excellent impact while maintaining low water opacity. Combining these three attributes into a single particle results in a highly effective core-shell modifier for polymer compositions.These compositions are expected to have great value in automotive, building and construction, lighting, optics, electronics, transportation, electricity, signage and displays, household appliances, consumer goods, coatings, medicine, cosmetics, UV personal care products, packaging and additive manufacturing applications. SUMMARY OF THE INVENTION The invention, in a first aspect, relates to a latex composition comprising core-shell particles, wherein the core-shell particles comprise: 0.5 to 40 wt%, preferably 1 to 20 wt%, more preferably 2 to 15 wt%, and more preferably 5 to 10 wt% of a hard-core polymer stage with a Tg > 0 °C, to 80 wt%, preferably 55 to 80 wt% of an inner polymer shell with a Tg < 0 °C, 5-50 wt%, preferably 10 to 20 wt% of an outer polymer shell with a Tg > 0 °C, and wherein the emulsifier-to-surface-area ratio of said core-shell particle is less than 1.5 x 10⁻⁴ g / m². The emulsifier-to-surface-area ratio of the core-shell particle is based on the core-shell particle as synthesized, without further processing. Examples of further processing would include, for example, washing, coagulation, and other similar post-polymerization processing methods. Secondly, the hard-core polymer stage of the coated core particles has at least 50 percent by weight of monomer units selected from the group of methacrylate ester units, acrylate ester units, styrene units, and mixtures thereof. In a third aspect of the invention, the latex composition of any of the above aspects, the inner polymeric coating has at least 50 percent by weight of monomeric units selected from the group of alkyl acrylates, styrenic dienes and mixtures thereof. In a fourth aspect of the invention, the latex composition of any of the above aspects has an outer polymeric coating having at least 50 percent by weight of monomeric units selected from the group of methacrylate ester units, acrylate ester units, styrenic units, and mixtures thereof. In a fifth aspect of the invention, the latex composition of any of the above aspects, the core-shell particles have a whole core-shell particle radius of 100 nm or less. In a sixth aspect of the invention, a core-shell particle has a radius of 100 nm or less and is composed of: 0.5 to 40 percent by weight, preferably 1 to 20 percent by weight, more preferably 2 to 15 percent by weight, and more preferably 5 to 10 percent by weight of a hard-core polymer stage with a Tg> 0 °C, to 80 percent by weight, preferably 55 to 80 percent by weight of an inner polymer shell with a Tg< 0 °C, and 5-50 percent by weight, preferably 10 to 20 percent by weight of an outer polymer shell with a Tg> 0 °C, ML / t / ZUZ I / UUZ l Ί O In a seventh aspect of the invention, an impact-modified polymer composition contains: 30-99 percent by weight of at least one polymeric resin as matrix, and 1-70 percent by weight of core-shell particles described in any of the above aspects. In an eighth aspect of the invention, the composition of the seventh aspect contains a polymeric resin that is a thermoplastic resin. In a ninth aspect of the invention, the composition of aspects 7 or 8 is the thermoplastic resin which is an acrylic resin. In the tenth aspect of the invention, in the composition of any of aspects 7 to 9, the concentration of core-shell particles in the composition is between 10 percent by weight and 60 percent by weight, preferably between 20 percent by weight and 50 percent by weight. In another aspect of the invention, the polymeric resin of the impact-modified composition is a thermosetting resin. In other aspects of the invention, the impact-modified composition of the foregoing aspects may have any of the following characteristics: an Izod Impact greater than 1.5 ft-lb / in; either an Izod Impact greater than 1.0 ft-lb / in, or a tensile modulus greater than 300,000 psi; or either an Izod Impact of at least 0.7 ft-lb / in and very low water opacity, as indicated by a delta opacity of less than 1 for a transparent sample, or a ΔE of less than 2 for a translucent or opaque sample after being immersed in deionized water at 70 °C for 24 hours and followed by conditioning at room temperature and 50% RH for >24 h; either an Izod Impact of at least 0.7 ft-lb / in., or a brightness of 60° after profile extrusion or co-extrusion of a part or layer 250 microns thick, greater than 30; or an Izod Impact of at least 0.7 ft-lb / in., an opacity at room temperature of less than 2 after being immersed in deionized water at 70 °C for 24 hours and followed by conditioning at room temperature and 50% RH for >24 h. In a further aspect of the invention, the impact-modified composition of any of the above aspects, the matrix and core-shell particles are selected such that the difference in refractive indices is within 0.08 units, preferably within 0.05 units, and more preferably within 0.01 units. In another aspect of the invention, the impact-modified composition of any of the above aspects has an Izod Impact of at least 0.7 ft-lb / in. and high transparency as indicated by a TLT of more than 90%. In another aspect of the invention, the impact-modified composition of any of the above aspects has an Izod Impact of at least 0.7 ft-lb / in., a water opacity of less than 10%, and a TLT of more than 90%. Another aspect of the invention relates to an article made from the impact-modified composition of any of the above aspects. The article of the above aspect, where the article is formed by melt processing, melt by additive manufacturing technique, infusion, wet compression molding, resin transfer molding or pultrusion. The article of any of the preceding claims, wherein the article is a multilayer article and at least one layer contains the impact-modified composition. The article of any of the preceding claims, wherein the article is a fiber-reinforced article. The article of any of the preceding claims, wherein the article is a building and construction article, decking, railings, cladding, fences, window and door profiles; an automotive article, automotive exterior moldings, an automotive interior, automotive mirror housings, fenders; an electronic article, earphones, mobile phone cases, computer cases; an energy-related article, a wind energy component, a custom foil article, an outer layer; an optical article, visibility films for street signage; a medical article, IV connectors, luers, diagnostic components; a sporting article, shoe soles, tennis rackets, golf clubs, skis; an infrastructure article, bridge supports, reinforcing bars;an item of outdoor equipment, a part for snow vehicles, a part for recreational vehicles, a part for personal watercraft, coatings, medical devices, cosmetics, UV personal care products, packaging and additively manufactured parts.; DETAILED DESCRIPTION OF THE INVENTION The invention relates to core-shell impact modifier compositions and polymer compositions comprising said core-shell impact modifiers. All percentages used herein are weight percentages and all molecular weights are weight-average molecular weights determined by gel permeation unless otherwise stated. All references cited are incorporated herein by this reference. The invention will be described in general terms and will also include an acrylic polymer / core-shell system as a model system. A person skilled in the art will recognize, based on the following description and examples, that other polymer matrices can be used with comparable results. ML / t / ZUZ I / UUZ / 10 COMPOSITION Core-Shell Impact Modifier The impact modifier of the invention is a sequentially produced, multi-stage polymer having a core-shell particle structure. The core-shell impact modifier comprises at least three layers (hard core / inner elastomeric shell layer / outer hard shell layer, known as the hard-core core-shell particle) or any greater number of layers, such as a soft seed core surrounded by a hard core / an intermediate elastomeric shell layer / a second, different elastomeric layer / and one or more high-Tg outer shell layers. Similar multi-layer structures are known in the art. In a preferred embodiment, the presence of a hard core layer provides a desirable balance of good impact strength, high modulus, and excellent UV resistance, which is not achieved with a core / shell modifier having a soft core layer. The core layer is defined herein as a polymer layer having at least two outer polymer layers. It need not be the innermost layer of the particle. The hard core layer (Tg > 0 °C, preferably Tfl > 20 °C) is commonly a single-composition polymer, but it can also include a combination of a small amount of a low-Tg seed upon which the hard core layer is formed. For example, a small amount of 5% rubber core seed dispersed in a hard inner layer would be included in the invention as a hard core layer, provided that the combination behaves as a hard core layer with a high Tg.The hard core layer can be selected from any combination of monomers that meets the Tg requirements. Preferably, the hard core layer is composed mainly of methacrylate ester units, acrylate ester units, styrenic units, or a mixture of these. Methacrylate ester units include, but are not limited to, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, pentadecil methacrylate, dodecyl methacrylate, isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, 2-hydroxyethyl methacrylate, and 2-methoxyethyl methacrylate.Acrylate ester units include, but are not limited to, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, isobornyl acrylate, phenyl acrylate, benzyl acrylate, phenoxyethyl acrylate, 2-hydroxyethyl acrylate, and 2-methoxyethyl acrylate. Preferably, acrylate ester units are chosen. ML / t / ZUZ I / UUZ l Ί O between methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and octyl acrylate. The styrene units include styrene and derivatives thereof, such as, but not limited to, alpha-methylstyrene and paramethylstyrene. In one embodiment, the hard core layer is entirely acrylic. In another embodiment, the hard core layer is acrylic with <30% styrenic monomer units. At least one or more intermediate inner shell layers are elastomeric, with a Tg of less than 0 °C, and preferably less than -20 °C. Preferred elastomers include polymers and copolymers of alkyl acrylates, dienes, styrenic acids, and mixtures thereof. Preferably, the soft intermediate layer is composed primarily of acrylate ester units. The acrylate ester units useful for forming the soft block include, but are not limited to, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate, isobornyl acrylate, phenyl acrylate, benzyl acrylate, phenoxyethyl acrylate, 2-hydroxyethyl acrylate, and 2-methoxyethyl acrylate.Preferably, the acrylate ester units are selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and octyl acrylate. Useful dienes include, but are not limited to, isoprene and butadiene. Useful styrenic compounds include, but are not limited to, alpha-methylstyrene and para-methylstyrene. In a preferred embodiment, the acrylate ester units comprise >75% of the inner elastomeric shell layer(s). Preferably, the total amount of elastomeric shell(s) in the impact modifier is 30 to 90 wt%, more preferably 40 to 85 wt%, and most preferably 55 to 80 wt%, based on the total weight of the impact modifier particle. The outer hard shell layer may consist of one or more shell layers, with a glass transition temperature (Tg) > 0 °C, more preferably Tg > 20 °C, preferably selected from the list above for the hard core. The outer shell layer may have the same or a different composition from the hard core layer. A level of functionalization may be included in the shell to aid in compatibility with the polymer matrix as described in US7195820B2. Hydrophilic monomers may also be included in the shell to improve shell coverage or enhance antiblocking properties. Examples of useful hydrophilic monomers include, but are not limited to, hydroxyalkyl (meth)acrylates, (meth)acrylic acid, (meth)acrylic amides, (meth)acrylic amines, polymerizable surfactants, and macromonomers containing hydrophilic moieties. In one aspect of the invention, the core-shell polymer is a three-stage composition in which the stages are present in ranges of 0.5 to 40 percent by weight, ML / E / ZUZ I / uyz l Ί O preferably 1 to 20 wt%, more preferably 2 to 15 wt% and even 5 to 10 wt%, of the hard core layer of the first stage; 10 to 80 wt%, preferably 55 to 80 wt%, of the second elastomeric inner shell stage; and 5 to 50 wt%, preferably 10 to 20 wt%, of the outer shell stage, all percentages based on the total weight of the three-stage polymer particle. The core-shell polymer particle shall have a radius of < 200 nm, more preferably < 100 nm. The small particle size is advantageous for maintaining excellent aesthetic properties such as transparency or high gloss when the core-shell particle is added to polymer compositions. In another aspect of the invention, the core-shell polymer is synthesized in a manner that produces a concentric circular particle, resembling a perfect target. This concentricity and circularity are advantageous for maximizing impact performance when used in a polymer composition. The core-shell polymer can be produced by any known technique for preparing sequentially produced, multi-stage polymers, for example, by emulsion polymerization of a mixture of monomers in subsequent stages in the presence of a preformed polymer product. In this specification, the expression "sequentially emulsion polymerized" or "sequentially emulsion produced" refers to polymers prepared in aqueous dispersion or emulsion in which successive monomer charges are polymerized on or in the presence of a preformed latex prepared by the polymerization of a previous charge and monomer stage. In this type of polymerization, each subsequent stage is bonded and intimately associated with the preceding stage. In a preferred embodiment, the impact modifier is prepared by sequential emulsion polymerization. As is known in the art, in this type of polymerization, emulsifying agents are commonly used to enable both the stabilization / transport of monomer supplies to the growing core-shell particle and the stabilization of the core-shell particle itself in the aqueous medium. Emulsifying agents are defined as any organic or inorganic molecule that has both a hydrophobic and a hydrophilic component in its structure. Any of the known surfactants, whether anionic, nonionic, or even cationic, can be used as an emulsifying agent.In particular, the emulsifying agent may be selected from anionic emulsifying agents, such as sodium or potassium salts of fatty acids, in particular sodium laurate, sodium stearate, sodium palmitate, sodium oleate, mixed sulfates of sodium or potassium and fatty alcohols, in particular sodium lauryl sulfate, sodium or potassium salts of sulfosuccinic esters, sodium or potassium salts of alkylarylsulfonic acids, in particular. ML / I sodium dodecylbenzenesulfonate and sodium or potassium salts of monosulfonates of fatty monoglycerides, or alternatively of non-ionic surfactants, such as the reaction products of ethylene oxide and alkylphenol or aliphatic alcohols, alkylphenols. Mixtures of such surfactants may also be used, if necessary. In a more preferred embodiment, the emulsion synthesis of this particle is carried out such that the ratio of the weight of the emulsifying agent to the surface area of ​​the core-shell particle is less than 1.5 x 10⁴ g / m² and preferably less than 9 x 10⁻⁵ g / m². This ratio is the ratio present in the emulsion or after a recovery process when no specific steps have been used to remove the emulsifying agents. Steps to remove emulsifying agents include, but are not limited to, latex coagulation, latex dialysis, or washing of already isolated particles; these methods can often improve the water opacity performance beyond what is claimed in this invention, but they introduce additional manufacturing steps and add costs.Spray drying is a well-established method for efficiently recovering core-shell particles at low temperatures without the need for costly additional steps to remove emulsifying agents. Having a low level of emulsifying agent in the particles recovered by spray drying is advantageous for maintaining lower water opacity when the core-shell particle is used in polymer compositions. In one aspect of the invention, where the impact modifier is prepared by sequential emulsion polymerization, the aqueous reaction mixture obtained at the end of the final emulsion polymerization stage, which is composed of an aqueous emulsion of the polymer according to the invention, is then treated to recover the polymer, in many cases in powder form. Spray drying is a particularly preferred technique. An effective but more expensive technique is coagulation, where the emulsion is subjected, depending on the emulsifying agent used, to a coagulating treatment by contacting it with a saline solution (CaCk or AICh) or a solution acidified with concentrated sulfuric acid, and then separating, by filtration, the solid product resulting from coagulation, which is then washed and dried to yield a graft copolymer in powder form.It is also possible to recover the polymer contained in the emulsion using drum drying, freeze-drying, or other methods known in the art. During any of these processes, additives such as talc, calcium carbonate, or silica can be used to aid in powder processing. Hard particles can be used in conjunction with the core-shell particles of the invention to further improve processing and antiblocking properties. The impact-modifying particle of the invention can be intimately combined with polymeric, organic or inorganic dispersing aids, anti-caking agents and / or other aids ML / t / ZUZ I / UUZ / ΊO process or other impact modifiers as commonly practiced by industry during spray drying or coagulation recovery processes. This process forms an impact-modifying composite particle, where the core-coated impact-modifying particle is intimately combined with the polymer, organic or inorganic additive, or process aid. The core-coated impact-modifying composite material particles can be produced and subsequently recovered in powder form by means known in the art, including, but not limited to, joint spray drying as separate streams in a spray dryer; mixing the core-coated particles and process aids as a dispersion, and spray drying the mixture; coagulation; and freeze-drying.applying a dispersion or solution of the process aids onto the core-shell powder, followed by drying; physical mixing of the impact modifier and process aid powders, which increases homogeneity in powder form and leads to a more homogeneous mixture in the matrix in a molten state; and physical combination followed by a weak melting combination of the impact modifier and process aid powders that allows softening and adhesion of the particles without complete melting. Impact modifier particles are present in the final impact modified polymer composition at a level of 5 to 80 percent by weight, preferably 10 to 60 percent by weight, and more preferably 20 to 50 percent by weight, based on the total composition. Polymer composition The resin used as the matrix polymer in the compositions of the invention may be any thermoplastic or thermoset. Particularly preferred thermoplastics include, but are not limited to, acrylic polymers, styrenic polymers, polyolefins, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyvinyl chloride (PVC), polycarbonate (PC), thermoplastic polyurethane (PU), polylactic acid (PLA), thermoplastic fluoropolymers, polyamides, or mixtures thereof. Particularly preferred thermoset polymers include, but are not limited to, epoxies, unsaturated polyester resins, vinyl ester resin, thermoset polyurethanes, urea formaldehyde, melamine formaldehyde, UV-curable acrylics, and thermosets. Styrenic polymers, as used in this document, include, but are not limited to, polystyrene, high-impact polystyrene (HIPS), acrylonitrile-butadiene-styrene (ABS) copolymers, acrylonitrile-styrene-acrylate (ASA) copolymers, styrene-acrylonitrile (SAN) copolymers, methacrylate-acrylonitrile-butadiene-styrene (MABS) copolymers, styrene-butadiene-styrene (SB) copolymers, styrene-butadiene-styrene (SBS) block copolymers and their partially or fully hydrogenated derivatives, styrene-isoprene-styrene (SIS) block copolymers and their partially or fully hydrogenated derivatives, styrene-isoprene-styrene (SIS) block copolymers and their partially or fully hydrogenated derivatives, styrene-(meth)acrylate copolymers such as Styrene-methyl methacrylate (S / MMA) copolymers, and mixtures thereof. A preferred styrenic polymer is ASA. Acrylic polymers, as used herein, include, but are not limited to, homopolymers, copolymers, and terpolymers comprising alkyl methacrylates. The alkyl methacrylate monomer is preferably methyl methacrylate, which may constitute from 51 to 100 percent of the monomer mixture, preferably more than 60 percent by weight, more preferably more than 75 percent by weight, and most preferably more than 85 percent by weight. The remaining monomers used to form the polymer are selected, but are not limited to, acrylates, methacrylates, and / or other vinyl monomers.Other methacrylate, acrylate, and vinyl monomers useful in monomer blending include, but are not limited to, methyl acrylate, ethyl acrylate and ethyl methacrylate, butyl acrylate and butyl methacrylate, isooctyl methacrylate and isooctyl acrylate, lauryl acrylate and lauryl methacrylate, lauryl acrylate and lauryl methacrylate, stearyl methacrylate, isobornyl acrylate and isobornyl methacrylate, methoxyethyl acrylate and methacrylate, 2-ethoxyethyl acrylate and methacrylate, dimethylaminoethyl acrylate and dimethylaminomethyl methacrylate monomers, styrene, and its derivatives. Alkyl (meth)acrylic acids such as (meth)acrylic acid and acrylic acid can also be useful for monomer blending. Small levels of multifunctional monomers can also be used as crosslinking agents. A preferred acrylic polymer is a copolymer of methyl methacrylate and 2–16 percent of one or more C1–4 acrylates. The thermoplastic or thermoset polymers of the invention can be manufactured by any means known in the art, including emulsion polymerization, bulk polymerization, solution polymerization, and suspension polymerization. In one embodiment, the polymer matrix has a weighted average molecular weight of between 50,000 and 5,000,000 g / mol, and preferably from 75,000 to 150,000 g / mol, as measured by gel permeation chromatography (GPC). The molecular weight distribution of the polymer matrix can be monomodal or multimodal with a polydispersity index greater than 1.5. In one embodiment, the composition of the polymer matrix and core-shell particle are chosen so that the refractive index is within 0.008 units, preferably within 0.005 units and more preferably within 0.001 units, thus enabling a transparent formulation. In another embodiment, dyes or pigments are added to the composition to allow for a translucent or opaque material. The level of pigment or dye in the composition is preferably 0.2 to 25 percent by weight, preferably 0.5 to 20 percent by weight, and most preferably 1 to 5 percent by weight, based on the total composition. The addition of the dye or pigment can produce a transparent article (having an opacity level of less than 10 percent, and preferably less than 3 percent); a translucent article (having an opacity level of 10 percent); or a translucent article (having an opacity level of 10 percent). ML / I river at 35 percent, preferably 15 to 25 percent or an opaque article. The useful dyes and pigments of the invention include, but are not limited to: Nanocarbon materials such as graphite or carbon nanotubes, cadmium zinc sulfide, Cl Pigment Yellow 35, (CAS Reg. No. 8048-07-5, SCOPE No. 01-2119981639-18-0001), cadmium sulfoselenide orange, Cl Pigment Orange 20, (CAS Reg. No. 12656-57-4, SCOPE No. 012119981636-24-0001), cadmium sulfoselenide red (Cl Pigment Red 108, CAS Reg. No. 5833934-7, N.Scope ° 01 -2119981636-24-0001), Carbon Black (PBIk-7), TiO2(PW-6), BaSO4(PW21 and PW-22), CaCO3(PW-18), PbCO3, Pb (OH)2, (PW1), MACROLEX® Yellow 6G, MACROLEX® Yellow 3G, MACROLEX® Yellow G, MACROLEX® Yellow E2R, MACROLEX® Yellow RN, MACROLEX® Orange 3G, MACROLEX® Orange R, MACROLEX® Red E2G, MACROLEX® Red A MACROLEX® Red EG, MACROLEX® Red G, MACROLEX® Red H, MACROLEX® RedB, MACROLEX® Red 5B, MACROLEX® Red Violet, MACROLEX®Violeta 3R, MACROLEX® Violet B, MACROLEX® Violet 3B, MACROLEX® Blue 3R, MACROLEX® Blue RR, MACROLEX® Blue 2B, MACROLEX® Green 5B, MACROLEX® Green G, MACROLEX® FluorescentYel. and MACROLEX®. Other additives: The composition may optionally contain one or more typical additives for polymer compositions used in usual effective quantities, including, but not limited to, other impact modifiers (linear block and core-shell copolymers), stabilizers, plasticizers, fillers, additives to improve scratch and / or wear resistance, coloring agents, pigments, antioxidants, anti-static agents, surfactants, toner, refractive index matching additives, additives with specific light diffraction, light absorption or light reflection characteristics, dispersing aids, radiation stabilizers such as poly(ethylene glycol), poly(propylene glycol), butyl lactate and carboxylic acids such as lactic acid, oxalic acid and acetic acid, light modification additives, such as polymeric or inorganic spherical particles with a particle size between 0.5 microns and 1000 microns.The amount of additives included in the polymer composition can vary from approximately 0% to approximately 70% of the combined weight of polymer, inorganic mineral oxide, and additives. Generally, it ranges from approximately 0.5% to approximately 45%, preferably from approximately 5% to around 40%. The additives can be added to the composition before it is added to the extruder, or they can be added to the molten composition through the extruder. PROSECUTION Synthesis process of the core-shell composite impact modifier The core-shell polymer of the invention is preferably synthesized by ML / t / ZUZ I / UUZ / 10 Free-radical emulsion polymerization. A general procedure for producing a 4-step core-shell polymer particle will be described. A person skilled in the art may modify this procedure to form other core-shell particles useful as impact modifiers. In a first stage (hard core layer), an emulsion is prepared containing, per part by weight of monomers to be polymerized, 1 to 10 parts of water, 0.001 to 0.03 parts of an emulsifying agent, a portion of a mixture of (meth) acrylate monomers, and at least one polyfunctional crosslinker. The reaction mixture thus formed is stirred and maintained at a temperature ranging from 45 °C to 85 °C, and preferably in the 60–80 °C range. Then, 0.0001 to 0.005 parts of a free-radical generating catalyst are added along with equal parts of an activating compound that increases the radical flux. The reaction mixture thus formed is maintained at a temperature of, for example, between room temperature and 100 °C, and stirred for a period sufficient to achieve virtually complete conversion of the monomers.Next, further additions of alkyl acrylate monomer(s) and grafting agent are added simultaneously to the phase thus obtained, as well as, at the same time, 0.0001 to 0.005 parts of a free radical generating catalyst, until the target particle size is reached. In a second stage, this core is grafted with a selection of monomers that will form a polymer with a Tg < 0 °C (inner shell). To achieve this, an appropriate amount of this monomer mixture is added to the reaction mixture resulting from the first stage, in order to obtain a grafted copolymer containing the desired amount of grafted chains, as well as, where applicable, additional amounts of emulsifier and a catalyst radical, also within the ranges defined above. The resulting mixture is then held at a temperature above the aforementioned range, with stirring, until virtually complete conversion of the graft monomers is achieved. As described above, any of the known surfactants, whether anionic, non-ionic, or even cationic, can be used as the emulsifying agent.In particular, the emulsifying agent may be selected from anionic emulsifying agents, such as sodium or potassium salts of fatty acids, in particular sodium laurate, sodium stearate, sodium palmitate, sodium oleate, mixed sodium or potassium sulfates and fatty alcohols, in particular sodium lauryl sulfate, sodium or potassium salts of sulfosuccinic esters, sodium or potassium salts of alkyl isulfonic acids, in particular sodium dodecylbenzenesulfonate, and sodium or potassium salts of monosulfonates of fatty monoglycerides, or alternatively from nonionic surfactants, such as the reaction products of ethylene oxide and alkylphenols or aliphatic alcohols, alkylphenols. Mixtures of such surfactants may also be used, if necessary. ML / t / ZUZ I / UUZ l Ί O In one embodiment, the emulsion can be prepared in a semi-continuous process, preferably at reaction temperatures of 60 to 90 °C, and preferably 75 °C to 85 °C. In a third step, this elastomer layer is grafted with a selection of monomers that will form a polymer with a Tg > 0 °C (outer shell). To achieve this, a suitable quantity of this monomer mixture is added to the reaction mixture resulting from the second step, in order to obtain a grafted copolymer containing the desired amount of grafted chains, as well as, where applicable, additional quantities of emulsifier and a catalyst radical, also within the ranges defined above. The resulting mixture is then held at a temperature within the range for step 2, with stirring, until virtually complete conversion of the graft monomers is achieved. As described above, any of the known surfactants, whether anionic, non-ionic, or even cationic, can be used as the emulsifying agent.In one embodiment, the emulsion can be prepared in a semi-continuous process, preferably at reaction temperatures of 60-90 °C, and preferably from 75 °C to 85 °C. In a fourth stage, the process of the third stage is repeated so that the thickness of the shell will increase and the resulting latex can be isolated into a powder by spray drying. In general, the preferred catalysts that can be used in all stages are compounds that give rise to free radicals under the temperature conditions chosen for polymerization. These compounds can be, in particular, peroxide compounds, such as hydrogen peroxide, alkali metal persulfates, and in particular sodium or potassium persulfate, ammonium persulfate; percarbonates, peracetates, perborates, peroxides such as benzoyl peroxide or lauroyl peroxide, or hydroperoxides such as eumene hydroperoxide, diisopropylbenzene hydroperoxide, para-menthane hydroperoxide, tert-amyl hydroperoxide, or tere-butyl hydroperoxide.However, it is preferable to use, in the central stage, redox-type catalytic systems formed by the combination of a non-ionic peroxide compound, for example t-butyl hydroperoxide as mentioned above, with a reducing agent, in particular such as alkali metal sulfite, alkali metal bisulfite, sodium formaldehyde sulfoxylate (NaHSO.Sub.2.HCHO), ascorbic acid, glucose, and in particular those of such catalytic systems that are water-soluble, for example t-butyl hydroperoxide / bruggolite ff7 or diisopropylbenzene hydroperoxide / sodium formaldehyde sulfoxylate.It is also possible to add to the polymerization mixture of one and / or other stages, chain-limiting compounds, and in particular mercaptans such as dodecyl mercaptan, isobutyl mercaptan, octyl mercaptan, dimercapto dioxaoctane, or isooctyl mercaptopropionate, in order to control the molecular mass of the core and / or the chains grafted onto the core, or alternatively compounds such as phosphates, in order to control the. ML / I / 10 ionic strength of the polymerization mixture. Process of incorporating core-shell particles of core-shell composite particles into a polymer composition The polymer matrix and the core-shell particle or composite core-shell particle can be combined in several different ways to provide a well-dispersed impact modifier in the composition. A preferred process for thermoplastic matrices involves a melt processing step. A particularly preferred method is mixing the thermoplastic matrix with the core-shell particle in an extruder such as a twin-screw extruder. The key is to achieve good dispersion of the core-shell particle. Other means of combining the thermoplastic matrix with the core-shell particle or core-shell composite particle include, but are not limited to: 1.) Mixing the thermoplastic polymer matrix with the core-shell particle where both materials are in a colloidal state. This latex mixture can be used as is or followed by solids recovery by a method such as spray drying or coagulation. 2.) Direct incorporation of the core-shell particle into liquid resin (with the liquid resin prior to core-shell addition comprising at least 25% matrix monomer) which is then polymerized (such as MMA cell molding, liquid composite resin polymerization, or an additive manufacturing technique such as stereolithography (SLA)). 3.) Solvent molding of the particles and dissolved matrix polymer. 4.) Powder mixing followed by melt processing such as, but not limited to, extrusion, coextrusion, injection molding, compression molding or thermoforming 5.) Powder mixing followed by an additive manufacturing technique such as selective laser sintering (SLS). For thermoset resin, a preferred method is the physical mixing of the core-shell particle or core-shell composite particle into the liquid resin before complete curing occurs. The thermoset core-shell mixture can then be processed by melting, UV curing, or an additive manufacturing technique such as SLA to form a thermoset or adhesive article. The thermoset core-shell mixture can also be processed using techniques such as infusion, resin transfer molding, or pultrusion to form a fiber-reinforced composite structure. Other methods may include, but are not limited to, powder mixing, for example, to incorporate the core-shell particle into a solid epoxy coating, followed by an additive manufacturing technique such as SLS. Articles In the case of thermoplastic matrices, articles and test plates are preferably formed by heat treatment. Useful heat processing methods include, but are not limited to, injection molding, extrusion and coextrusion, film extrusion, blow molding, lamination, extrusion lamination, rotomolding, infusion, pultrusion, compression molding, and fusion deposition modeling. For liquid thermoplastic resins, techniques such as casting, adhesive curing, or SLA can be used, while for fiber-reinforced thermoplastic articles, processing techniques such as infusion, resin transfer molding, or pultrusion can be used. Additive manufacturing techniques such as fusion deposition modeling (FDM) or laser sintering can also be used. For thermoset articles, processes such as casting, adhesive curing, infusion, resin transfer molding, wet compression molding, pultrusion, spraying, and lamination can be used to form articles and test plates. Additive manufacturing techniques such as SLA or SLS can also be used. Other additives, as well as optional pigments and dyes, can be dry-mixed into the composition before heat processing in the final product. For some additives, such as pigments or dyes, a masterbatch containing a concentrate could be used. The invention also contemplates multilayer articles. The composition of the invention can be used on the outer side, the inner side, or any intermediate layer. The multilayer article could be two-layered or have several layers, which could include adhesive and / or bonding layers. The invention also contemplates fiber-reinforced articles. Useful fibers may include, but are not limited to, glass, carbon, or natural fibers. Properties The polymer composition of the invention, when processed to form an article or test sample, provides a unique combination of impact resistance, aesthetics, and low water opacity that are useful in various applications. In a preferred embodiment, the articles have high impact resistance. When measured using the notched Izod test (ASTM D256), the polymer compositions achieve an impact resistance of > 1.5 ft-lb / in. In another preferred configuration, the articles have a high impact strength but maintain a high modulus due to the need to use lower loads of the highly effective impact modifier. When measured with notched Izod (ASTM D256), the polymer compositions achieve an impact strength of >1 ft-lb / in. but still maintain a tensile modulus of >300,000 psi (ASTM D638). In a preferred embodiment, the opaque / translucent articles of the invention have at least a medium impact level (Izod notched per ASTM 256 of > 0.7 ft-lb / in.) but maintain a high gloss even after profile extrusion. The gloss at 60° after profile extrusion or co-extrusion of a 250-micron-thick piece or layer is > 30 as measured with the Byk-Gardner microgloss meter. In a preferred embodiment, the opaque / translucent articles of the invention have at least ML / E / ZUZ I / 10 a medium impact level (notched Izod per ASTM 256 of > 0.7 ft-lb / in.), but the water opacity of the material is also very low, as indicated by the color value ΔE (measured by CIE L*a*b* on the X-Rite Color I7 spectrophotometer) of the test sample of less than 2.0, and preferably less than 1.0 after being exposed to 70 °C for 24 hours. In a particularly preferred embodiment, the opaque / translucent articles of the invention have at least a medium impact level (notched Izod per ASTM 256 of > 0.7 ft-lb / in.), a high gloss level (60° gloss after profile extrusion or profile co-extrusion of a 250-micron thick part or layer > 45 as measured by the Byk-Gardner microgloss meter), and the water opacity of the material is also very low, as indicated by the ΔE color value (measured by CIE L*a*b* on the X-Rite Color I7 spectrophotometer) of the test sample of < 2 after being exposed to 70°C for 24 hours. In a preferred embodiment, the transparent articles of the invention have at least a medium impact level (notched Izod per ASTM 256 of > 0.7 ft-lb / in.) but maintain high transparency, >90% Total Light Transmission (TLT) as measured by ASTMD1003. In a preferred embodiment, the transparent articles of the invention have at least a medium impact level (notched Izod per ASTM 256 of > 0.7 ft-lb / in.) but the water opacity of the material is also very low, as indicated by a change in opacity of < 5 units (measured according to ASTM D1003) after being immersed in deionized water at 70°C for 24 hours and conditioned at room temperature with 50% RH for >24 h thereafter. In a preferred embodiment, the transparent articles of the invention have at least a medium impact level (notched Izod per ASTM 256 of > 0.7 ft-lb / in.) and high transparency (TLT > 90% as measured with ASTM D1003) and the water opacity of the material is also very low, as indicated by a change in opacity of < 2 units (measured according to ASTM D1003) after being immersed in deionized water at 70°C for 24 hours and conditioned at room temperature with 50% RH for >24 h thereafter. The invention also addresses the low-temperature opacity of the polymer compositions due to the invention's preferred small particle size. A change in opacity of <20% (measured according to ASTM D1003) is anticipated when temperatures increase from room temperature to 80°C. USES The composition of the invention is useful for forming high-impact, aesthetically pleasing, and low-turbidity articles for applications including, but not limited to, building and construction (such as decking, railings, cladding, fences, and door and window profiles); automotive applications (such as exterior and interior moldings, mirror housings, and fenders); and electronics (such as earphones, cell phone cases, and housings for... ML / t / ZUZ I / UUZ l Ί O computers); energy applications (such as wind power), custom sheet applications, especially as caps; optical applications (visibility films for street signage); medical (intravenous connections such as luers, diagnostic components), sporting goods (such as shoe soles, tennis rackets, golf clubs, skis), infrastructure (such as bridges, rebar), outdoor equipment (such as snowmobiles, recreational vehicles, jet skis) and applications made by any type of additive manufacturing. Within this specification, embodiments have been described in a manner that allows for a clear and concise specification, but it is intended and will be appreciated that the embodiments can be combined or separated in various ways without departing from the invention. For example, it will be appreciated that all the preferred features described herein are applicable to all aspects of the invention described herein. EXAMPLES: Testing methods: The samples for physical and optical testing are injection molded to a thickness of 3.18 ± 0.05 mm with other dimensions specified in ASTM standards. A. Tg: The glass transition temperature (Tg) is measured by DSC (differential scanning calorimetry) in accordance with ISO 11357-2 (2013) and ISO 11357-3 (2013), according to the following protocol: 1: Balance at 20.00 °C 2: Cool at a rate of 10.00 °C / min to -50.00 °C 3: Maintain this temperature for 5.00 min. 4: Heat at a rate of 20.00 °C / min up to 250.00 °C 5: Maintain this temperature for 5.00 min. 6: Cool at a rate of 10.00 °C / min to -50.00 °C 7: Maintain this temperature for 5.00 min. 8: Heat at a rate of 20.00 °C / min to 250.00 °C B. Emulsifier-to-surface ratio. The emulsifier-to-surface-area ratio is a calculated value. The volumetric mean particle size and mean particle number are determined by light scattering on latex using a NICOMP380 dynamic light scattering instrument. Polymer solids are determined by weighing an aluminum tray, adding latex polymer, and weighing it again, then evaporating the water in an oven to obtain the polymer solids as a mass percentage. The particle surface area is calculated based on the volumetric mean radius, which was determined by light scattering. The amount of emulsifier added to the latex is assumed to be present on the particle surface. The polymer density is obtained by taking the mass of a sample of solid polymer and dividing it by the volume.Using the average number of particles and the volumetric average particle size, the calculated density of the calculated surface area and the polymer concentration, and the polymer density, the relationship between the emulsifier and the surface area can be calculated. C. Water opacity. This is the measured difference in opacity between an injection-molded sample conditioned at room temperature and humidity (23 °C, 50% relative humidity, RH) and the opacity of a sample after immersion in 70 °C deionized water for 24 hours, followed by conditioning at room temperature and 50% relative humidity, measured with BYK HazeGard Plus according to ASTM D1003 for samples with total light transmission greater than 50%. Alternatively, for opaque samples, the difference in final color from initial color (Delta E) may be used instead of (Delta Haze), as described above. D. Brightness: The surface brightness was measured at a 60-degree measuring angle using a BYK Spectro-Guide. E. Notched Izod impact measured in accordance with ASTM D256 Abbreviations used in the examples: MMA = methyl methacrylate EA = ethyl acrylate BA = butyl acrylate MA = methyl acrylate Sty = styrene ALMA = allyl methacrylate GMAA = glacial methacrylic acid KDDBS = potassium dodecylbenzenesulfonate Example 1 This example illustrates the preparation of a multi-stage, sequentially produced polymer composition. The ratio of the three stages was 10 / / 75 / / 15 The composition of the three stages was Stage 1: 79 / 20 / 1 MMA / BA / ALMA Stage 2: 82 / 17 / 1 BA / Sty / ALM A Stage 3: 100 MMA A monomer feed consisting of step 1 was emulsified in deionized water using KDDBS. The emulsion was heated to between 50 and 70 °C and initiated with a 1:1 weight ratio of tere-butyl hydroperoxide to bruggolite (R) FF7 reducing agent to obtain a suitable polymerization rate. The temperature was increased to at least 80 °C and, after a With the conversion almost complete, potassium carbonate was added to regulate the pH for stages 2 and 3. The stage 2 mixture was gradually fed in along with a controlled amount of KDDBS to limit the generation of new particles and maintain latex stability. Potassium persulfate was added concurrently with the stage 2 mixture to control the polymerization rate, residual salt content, and pH level. After this addition, the latex was allowed to cure until <1% residual monomer remained. The stage 3 monomer mixture was gradually added with a limited amount of surfactant to control particle growth. After this addition, the latex was allowed to cure until <0.1% residual monomer remained. The polymer was isolated by coagulation, freeze-drying, or spray-drying. Example 2 This polymer was prepared in a similar manner to Example 1 except that it had different step ratios: The ratio of the three stages was 2 / / 75 / / 23 The composition of the three stages was Stage 1: 8 / 90 / 2 MMA / Sty / ALMA Stage 2: 85 / 14 / 1.0 BA / Sty / ALM A Stage 3: 100 MMA Example 3 This polymer was prepared in a similar manner to Example 1 except that it had different step ratios: The ratio of the three stages was 6 / / 75 / / 19 The composition of the three stages was Stage 1: 8 / 90 / 2 MMA / Sty / ALMA Stage 2: 84 / 15 / 1.0 BA / Sty / ALM A Stage 3: 99 / 1 MMA / GMAA Example 4 This polymer was prepared in a similar manner to Example 1 except that it had different step ratios: The ratio of the three stages was 7 / 75 / 18 The composition of the three stages was Stage 1: 80 / 10 / 9.8 / 0.2 MMA / Sty / BA / SOUL Stage 2: 84 / 15 / 1 BA / Sty / ALMA Stage 3: 99 / 1 MMA / BA ML / t / ZUZ I / UUZ l Ί O Examples 5 and 6 (comparative) This example illustrates the preparation of a multi-step polymer, produced sequentially from the given composition, using the method of the above technique, directed to a radius of 80 nm and 150 nm, respectively. The ratio of the three stages was 15 / / 65 / / 20 The composition of the three stages was Stage 1: 74.8 / 25 / 0.2 MMA / EA / ALMA Stage 2: 83.5 / 15.5 / 1.0 BA / Sty / ALMA Stage 3: 95 / 5 MMA / EA A monomer feed consisting of 34% of Stage 1 was emulsified in water using KDDBS as the emulsifier and potassium carbonate to control the pH, and polymerized using potassium persulfate at elevated temperatures. The remaining portion of Stage 1 was then added to the preformed polymer emulsion and polymerized using potassium persulfate at elevated temperatures, controlling the amount of soap added to avoid the formation of a significant number of new particles. The monomers from Stage 2 were then added and polymerized using potassium persulfate at elevated temperatures, again controlling the amount of soap added to avoid the formation of a significant number of new particles.The remaining portion from Stage 3 was then added to the preformed polymer emulsion and polymerized using potassium persulfate at elevated temperatures, controlling the amount of soap added to avoid the formation of a significant number of new particles. The polymer was isolated by coagulation, freeze-drying, or spray-drying. The ratio of the three stages was 35 / / 45 II20 The composition of the three stages was Stage 1: 95.8 / 0.4 / 0.2 MMA / EA / SOUL Stage 2: 80 / 18 / 2.0 BA / Sty / ALMA Stage 3: 96 / 4 MMA / EA Examples 7-13 The polymers from Examples 1-6 were mixed with the specified amount of acrylic copolymer matrix in an extruder. Example # 7 8 9 10 11(Comp) 12(comp) 13(comp) % by weight of impact modifier 50%E1 50%E2 40%E3 35%E4 40%E5 40%E6 42.5%E6 Elastomeric % by weight of acrylic copolymer matrix 50% 50% 60% 60% 60% 60% 52.5% % colorant 0 0 0 5% 0 0 5% Particle radius (+- 10 nm) 60±5 120±5 55±5 85±5 80±5 150±5 150±5 Average surfactant mass per particle surface (g / m2) 6.7 x 105 8.5 x 105 9.9x10' 5 1.6 x 10'4 1.6 x 10'4 1.8 x 10'4 1.8x 10'4 Total light transmission (TLT) % 91.5 83.5 83 0 92 92 0 Opacity 1.0 6.0% 4.6 N / C 1.0 1.9 N / C Opacity after immersion at 70°C for 24 hours 1.9 N / C 10 16 N / C Notched Izod Impact Strength (ft lb / in) 1.87 2.65 1.19 1.1 0.70 1.1 1.2 Young's Modulus 215 kpsi N / C 303 kpsi N / C 355 kpsi 305 kpsi 250 kpsi Delta E after immersion at 70°C for 24 hours N / C 0.9 N / C 2.0 ML / t / ZUZ I / UUZ l Ί O Examples 7-13 were cast in 1 / 8 in. plates and 1 / 8 in. x 0.5 in. x 2.5 in. Izod bars. Energy per notch length was measured on a Ceast Izod testing machine in accordance with ASTM D256. This table clearly shows the advantages of having an optimized elastomeric polymer dispersed in an acrylic copolymer matrix containing lower levels of surfactant. Example 7 exhibits 2.67 times greater impact strength and 8.1 fewer units of opacity after immersion at 70°C for 24 hours than Example 11; meanwhile, optical properties such as TLT and opacity are maintained. It also illustrates the advantages of a mixed initiator system during core-shell synthesis. Example 8 demonstrates that an impact strength of 2.65 ft-lb / in can be achieved with only a minor compromise of optical properties. Example 9 shows that a tensile modulus of over 300,000 psi can be achieved with an impact strength of 1.19 ft-lb / in. Example 14-15 (profile extrusion) Examples 14 and 15 consist of the materials from Example 10 and Example 13, respectively, coextruded onto PVC using profile extrusion, where the coating layer thickness is 200–250 micrometers. The PVC thickness was 1160–1270 micrometers. The GVHIT impact strength of the composite was then tested according to ASTM-D4226-00. ML / t / ZUZ I / UUZ / ΊΟ GVHIT Brightness at 60° Example 14 1.3 in-lb. / mil 45±3 Example 15 1.1 in-lb. / mil 15±3 The advantages of materials like Example 14 over more traditional acrylics like Example 15 are readily apparent. Example 15 does not meet the gloss requirements enabled by the invention.

Claims

1.) A latex composition comprising core-shell particles, wherein said core-shell particles comprise: a. 0.5 to 40 wt. percent, preferably 1 to 20 wt. percent, more preferably 2 to 15 wt. percent, and more preferably 5 to 10 wt. percent of a hard-core polymer stage with a Tg > 0 °C, b. 10 to 80 wt. percent, preferably 55 to 80 wt. percent of an inner polymer shell with a Tg < 0 °C, c. 5-50 wt. percent, preferably 10 to 20 wt. percent of an outer polymer shell with a Tg > 0 °C, wherein the emulsifier-to-surface-area ratio of said core-shell particle is less than 1.5 x 10⁻⁴ g / m², based on the synthesized core-shell particles and without further processing. 2.) The latex composition of claim 1, wherein said hard-core polymeric stage comprises at least 50 percent by weight of monomer units selected from the group consisting of methacrylate ester units, acrylate ester units, styrene units, and mixtures thereof. 3.) The latex composition of claim 1, wherein the inner polymeric coating comprises at least 50 percent by weight of monomeric units selected from the group consisting of alkyl acrylates, dienes, styrenic acids, and mixtures thereof. 4.) The latex composition of claim 1, wherein the outer polymeric coating comprises at least 50 percent by weight of monomer units selected from the group consisting of methacrylate ester units, acrylate ester units, styrene units, and mixtures thereof. 5.) The latex composition of claim 1, wherein the radius of the entire core-shell particle is 100 nm or less. 6.) A core-shell particle having a radius of 100 nm or less, comprising: a. 0.5 to 40 wt. percent, preferably 1 to 20 wt. percent, more preferably 2 to 15 wt. percent, and more preferably 5 to 10 wt. percent of a hard-core polymeric stage with a Tg > 0 °C, b. 10 to 80 wt. percent, preferably 55 to 80 wt. percent of an inner polymeric shell with a Tg < 0 °C, and c. 5-50 wt. percent, preferably 10 to 20 wt. percent of an outer polymeric shell with a Tg > 0 °C, 7.) An impact-modified polymer composition comprising: a.) 30-99 percent by weight of at least one polymer resin as matrix, and b.) 1-70 percent by weight of core-shell particles according to claim 6. 8.) The impact-modified composition of claim 7, wherein the polymer resin is a thermoplastic resin. 9.) The impact-modified composition of claim 8, wherein the thermoplastic resin is an acrylic resin. 10.) The impact-modified composition of claim 7, wherein the core-shell particle concentration is between 10 percent by weight and 60 percent by weight, preferably between 20 percent by weight and 50 percent by weight. 11.) The impact-modified composition of claim 7, wherein the polymer resin is a thermoset resin. 12.) The impact-modified composition of claim 7, wherein a sample made from said impact-modified composition has an Izod Impact greater than 1.5 ft-lb / in. 13.) The impact-modified composition of claim 7, wherein a sample made from said impact-modified composition has an Izod Impact greater than 1.0 ftlb / in., and a tensile modulus greater than 300,000 psi. 14.) The impact-modified composition of claim 7, wherein a sample made from said composition has an Izod Impact of at least 0.7 ft-lb / in. and a very low water opacity, wherein a transparent composition has a delta opacity of less than 1, as measured by ASTM D1003, after immersion in deionized water at 70 SC for 24 hours. 15.) The impact-modified composition of claim 4, wherein a sample made with said composition has a delta E of less than 2, as measured by ASTM D1003, after being immersed in deionized water at 70 2C for 24 hours. 16.) The impact-modified composition of claim 7, wherein a sample made from said composition has an Izod Impact of at least 0.7 ft-lb / in; and a brightness of 60° after extrusion of a profile part or layer of 250 microns thickness greater than 30. 17.) The impact-modified composition of claim 7, wherein a sample made from said composition has an Izod Impact of at least 0.7 ft-lb / in; a water opacity of less than 1 after being exposed to 70°C for 24 h; and a brightness of 60° after extrusion of a 250 micron part or layer of thickness greater than 30. 18.) The impact-modified composition of claim 7, wherein said matrix and core-shell particles are selected such that the difference in refractive indices is within 0.08 units, preferably within 0.05 units and more preferably within 0.01 units. 19.) The impact-modified composition of claim 7, wherein a sample made from said composition has an Izod Impact of at least 0.7 ft-lb / in. and high transparency as indicated by a TLT of more than 90%. 20.) The impact-modified composition of claim 18, wherein a sample made from said composition has an Izod Impact of at least 0.7 ft-lb / in., an opacity of less than 2 units after immersion in 70°C for 24 hours, and a TLT of more than 90%. 21.) An article comprising the impact-modified composition of claim 7. 22.) The article of claim 21, wherein said article is formed by melt processing, melt by additive manufacturing technique, infusion, wet compression molding, resin transfer molding or pultrusion. 23.) The article of claim 21, wherein said article is a multilayer article, wherein at least one layer comprises the impact-modified composition of claim 7. 24.) The article of claim 21, wherein said article is a fiber-reinforced article. 25.) The article of claim 21, wherein said article is selected from the group consisting of: a construction and building article, decking, railings, cladding, fences, window and door profiles; an automotive article, automobile exterior moldings, an automobile interior, automobile mirror housings, fenders; an electronics article, earphones, mobile phone cases, computer cases; an energy-related article, a wind energy component, a custom sheet article, a cap; an optics-related article, visibility films for street signage; a medical article, IV connectors, luers, diagnostic components; a sporting article, shoe soles, tennis rackets, golf clubs, skis; an infrastructure article, bridge supports, reinforcing bars;an item of outdoor equipment, a snow vehicle, a recreational vehicle part, a personal watercraft part, an additive manufacturing part; automotive item, lighting item, optical item, transportation item, electrical item, signage and display item, household appliances, consumer goods, coating, cosmetics, personal care UV and packaging.