WO2018039454A1

WO2018039454A1 - Polymer composite compositions including kaolin

Info

Publication number: WO2018039454A1
Application number: PCT/US2017/048417
Authority: WO
Inventors: David W. DEWULF; Chinmay PESHAVE; John POULAKIS
Original assignee: Imerys Usa,Inc.
Priority date: 2016-08-26
Filing date: 2017-08-24
Publication date: 2018-03-01

Abstract

A polymer composite composition for manufacturing an article may include kaolin, an acicular material, and a polymer that may include at least one of nylons, polyesters, polyimides, polyamides, aromatic polyamides, polysulfides, polyetherketones, and polycarbonates. The kaolin, acicular material, and polymer may be combined to form the polymer composite composition. A method of reducing acicular material in a polymer composite composition including the acicular material and a polymer while maintaining a flexural modulus of an article including the polymer composite composition, may include substituting kaolin for at least a portion of the acicular material in the polymer composite composition.

Description

POLYMER COMPOSITE COMPOSITIONS INCLUDING KAOLIN

CLAIM FOR PRIORITY

[0001] This PCT International Application claims the benefit of priority of U.S. Provisional Application No. 62/380,046, filed August 26, 2016, the subject matter of which is incorporated herein by reference in its entirety.

DESCRIPTION

Field

[0002] The present disclosure relates to polymer composite compositions, and more particularly, to polymer composite compositions including kaolin.

Background

[0003] Many thermoplastic articles of manufacture are formed from plastic materials sometimes referred to as "engineering thermoplastics." Engineering thermoplastics may include polymers such as nylons, polyesters, aromatic polyamides, polysulfides, polyetherketones, and polycarbonates. Engineering thermoplastics may be used to form articles for which desirable characteristics may include high stiffness, resistance to solvents, barrier properties, high reflectivity surfaces, heat resistance, high impact strength, and/or resistance to creep. In order to enhance the strength or other desired characteristics of the articles formed from engineering thermoplastics, glass fibers may be incorporated into the polymers to form a composite material. However, the inclusion of glass fibers in engineering thermoplastics may have several drawbacks. For example, glass fibers may be relatively expensive, difficult to process, and sometimes adversely affect the surface qualities of the finished article.

[0004] Therefore, it may be desirable to provide alternative compositions and methods that provide at least some of the benefits adding glass fibers to polymers while reducing or eliminating the glass fibers. The compositions and methods disclosed herein may mitigate or overcome one or more of the possible drawbacks described above, as well as other possible drawbacks.

[0005] According to one aspect, a polymer composite composition for manufacturing an article may include kaolin, an acicular material, and a polymer that may include at least one of nylons, polyesters, polyimides, polyamides, aromatic polyamides, polysulfides, polyetherketones, and polycarbonates. The kaolin, acicular material, and polymer may be combined to form the polymer composite composition.

[0006] According to another aspect, a method of reducing acicular material in a polymer composite composition including the acicular material and a polymer while maintaining a flexural modulus of an article including the polymer composite composition, may include substituting kaolin for at least a portion of the acicular material in the polymer composite composition.

[0007] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Fig. 1 is a graph showing Young's modulus (GPa) vs. wt% of exemplary kaolin for fifteen samples of exemplary polymer composite compositions.

[0009] Fig. 2 is a graph showing ultimate tensile strength (UTS) (MPa) vs. wt% of exemplary kaolin for fifteen samples of exemplary polymer composite compositions.

[0010] Fig. 3 is a graph showing elongation at break (mm) vs. wt% of exemplary kaolin for fifteen samples of exemplary polymer composite compositions.

[0011] Fig. 4 is a graph showing flexural modulus (GPa) vs. wt% of exemplary kaolin for fifteen samples of exemplary polymer composite compositions.

[0012] Fig. 5 is a graph showing flexural strength (MPa) vs. wt% of exemplary kaolin for fifteen samples of exemplary polymer composite compositions.

[0013] Fig. 6 is a graph showing impact strength (ft-lb/in²) vs. wt% of exemplary kaolin for fifteen samples of exemplary polymer composite compositions.

[0014] Fig. 7 is a graph showing of flexural strength (MPa) vs. exemplary kaolin for twelve samples of exemplary polymer composite compositions.

[0015] Fig. 8 is a graph showing flexural modulus (GPa) vs. exemplary kaolin for twelve samples of exemplary polymer composite compositions.

[0016] Fig. 9 is a graph showing ultimate tensile strength (UTS) (MPa) vs. exemplary kaolin for twelve samples of exemplary polymer composite compositions.

[0017] Fig. 10 is a graph showing tensile modulus (MPa) vs. exemplary kaolin for twelve samples of exemplary polymer composite compositions,

[0018] Fig. 11 is a graph showing notched impact strength (kJ/m²) vs.

exemplary kaolin for twelve samples of exemplary polymer composite compositions. [0019] Fig. 12 is a graph showing heat deflection temperature (°C) vs.

exemplary kaolin for six samples of exemplary polymer composite compositions.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0020] According to some embodiments, a polymer composite composition for manufacturing an article may include hydrous kaolin, calcined kaolin, or a mixture of hydrous and calcined kaolin, an acicular material, and a polymer that may include at least one of nylons, polyesters, polyimides, polyamides, aromatic polyamides, polysulfides, polyetherketones, and polycarbonates. In some embodiments the hydrous kaolin, calcined kaolin, or mixtures thereof also undergoes a surface treatment. The kaolin, acicular material, and polymer may be combined to form the polymer composite composition. According to some embodiments, the polymer may include polyamides.

[0021] As used herein, "acicular" refers to particulates including, or derived from, slender, needle-like structures or crystals, or particulates having a similar form. According to some embodiments, the acicular material may include fiber. For example, the acicular material may include chopped fiber. According to some embodiments, the acicular material may include glass fiber, such as, for example, chopped glass fiber. According to other embodiments, the acicular material may include wollastonite. The glass may include silica or silicate and one or more of oxides of calcium, magnesium, and boron.

[0022] The morphology of a particulate may be characterized by "shape factor." As used herein, "platy" refers to particulates having a shape factor greater than 1. In contrast, particulates having a shape factor less than or equal to 1 would be considered to have a "blocky" morphology. [0023] "Shape factor" as used herein is a measure of an average value (on a weight average basis) of the ratio of mean particle diameter to particle thickness for a population of particles of varying size and shape, as measured using the electrical conductivity method according to the description in U.S. Pat. No. 5,576,617, the subject matter of which is incorporated herein by reference, an apparatus may be used to measure the shape factor of non-spherical particles by obtaining a fully- deflocculated suspension of the particles, causing the particles in the suspension to orientate generally in a first direction, measuring the conductivity of the particles suspension substantially in the first direction, and simultaneously or substantially simultaneously measuring the conductivity of the particle suspension in a direction transverse to the first direction. Thereafter, the difference between the two conductivity measurements may be determined to provide a measure of the shape factor of the particles in suspension. Measuring conductivity "substantially simultaneously" means to take the second conductivity measurement sufficiently close in time after the first conductivity measurement, such that the temperature of the suspension being measured will be effectively the same for each measurement.

[0024] According to some embodiments, the hydrous kaolin may include platy hydrous kaolin. For example, the hydrous kaolin may have a shape factor of at least 10. For example, the shape factor may be at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, or at least 80. According to some embodiments, the shape factor of the hydrous kaolin may range from 10 to 70, from 10 to 60, from 10 to 50, from 10 to 40, from 20 to 70, from 20 to 60, from 20 to 50, from 20 to 40, from 30 to 70, from 30 to 60, from 30 to 50, from 30 to 40, from 40 to 70, from 40 to 60, from 40 to 50, from 50 to 70, from 50 to 60, or from 60 to 70. [0025] According to some embodiments, the kaolin may include

surface-treated kaolin. For example, the kaolin may include kaolin surface-treated with at least one of silanes, aminosilanes, silicates, silicone fluids, emulsions, and siloxanes, or mixtures thereof. According to some embodiments, the kaolin may include kaolin surface-treated with aminosilanes.

[0026] According to some embodiments, the polymer composite composition may include at least 10 wt% kaolin relative to the total weight of the composition. For example, the polymer composite composition may include at least 20 wt% kaolin, at least 30 wt% kaolin, at least 40 wt% kaolin, or at least 50 wt% kaolin relative to the total weight of the composition.

[0027] Particle sizes and other particle size properties referred to in the present disclosure may be measured using a Sedigraph 5100 instrument, as supplied by Micromeritics Corporation. Using such a measuring device, the size of a given particle is expressed in terms of the diameter of a sphere of equivalent diameter, which sediments through the suspension, sometimes referred to as "an equivalent spherical diameter" or "esd." The median particle size, or the "dgo" value, is the value determined by the particle esd at which 50% by weight of the particles have an esd less than the dso value.

[0028] In a second method particle size is measured using a Malvern Particle Size Analyzer, Model Mastersizer, from Malvern Instruments. A helium-neon gas laser beam is projected through a transparent cell which contains the particles suspended in an aqueous solution. Light rays which strike the particles are scattered through angles which are inversely proportional to the particle size. The

photodetector array measures the quantity of light at several predetermined angles. Electrical signals proportional to the measured light flux values are then processed by a microcomputer system, against a scatter pattern predicted from theoretical particles as defined by the refractive indices of the sample and aqueous dispersant to determine the particle size distribution. Embodiments where D50 is less than 0.5 μπι were measured using the Malvern Particle Size Analyzer. Other methods and/or devices for determining particle size and related properties are contemplated.

[0029] According to some embodiments, the median particle size d₅o of the kaolin may be less than or equal to 2 microns. For example, the median particle size dso of the kaolin may be less than or equal to 1.5 microns, less than or equal to 1.4 microns, less than or equal to 1.3 microns, less than or equal to 1.2 microns, less than or equal to 1.1 microns, less than or equal to 1.0 micron, less than or equal to 0.9 microns, less than or equal to 0.8 microns, less than or equal to 0.7 microns, less than or equal to 0.6 microns, less than or equal to 0.5 microns, less than or equal to 0.4 microns, less than or equal to 0.3 microns, or less than or equal to 0.2 microns. According to some embodiments, the median particle size dso of the kaolin may be less than or equal to 0.5 microns (e.g., less than 0.3 microns) and the kaolin may include kaolin surface-treated with aminosilanes.

[0030] According to some embodiments, a polymer composite composition for manufacturing an article may include kaolin and a polymer that may include at least one of nylons, polyesters, polyimides, polyamides, aromatic polyamides,

polysulfides, polyetherketones, and polycarbonates. The kaolin and polymer may be combined to form the polymer composite composition. An article including the polymer composite composition including the kaolin may have a flexural modulus higher than the article including the polymer composite composition devoid of the kaolin.

[0031] According to some embodiments, an article including the polymer composite composition including the kaolin may have a flexural modulus at least 10% higher than the article including the polymer composite composition devoid of the kaolin. For example, the article including the polymer composite composition including the kaolin may have a flexural modulus at least 25% higher than the article including the polymer composite composition devoid of the kaolin. According to some embodiments, the article including the polymer composite composition including the kaolin may have a flexural modulus at least 40% higher than the article including the polymer composite composition devoid of the kaolin.

[0032] A method of reducing acicular material in a polymer composite composition including the acicular material and a polymer while maintaining a flexural modulus of an article including the polymer composite composition, may include substituting hydrous kaolin or calcined kaolin having a median particle size dso of less than 0.5 microns, for at least a portion of the acicular material in the polymer composite composition. According to some embodiments, the substituting may include substituting the hydrous kaolin or calcined kaolin having a median particle size dso of less than 0.5 microns, for the at least a portion of acicular material at least a 1:1 ratio of hydrous kaolin or calcined kaolin or a mixture thereof to acicular material based on weight. According to some embodiments, the substituting may include substituting the hydrous kaolin or calcined kaolin or a mixture thereof for the at least a portion of acicular material at a ratio of hydrous kaolin or calcined kaolin or a mixture thereof to acicular material based on weight ranging from 1 :4 to 4:1 , from 1:3 to 3:1, or from 1 :2 to 2:1.

[0033] According to some embodiments of the method, the kaolin may include platy hydrous kaolin or calcined kaolin having a median particle size dso of less than 0.5 microns, and the substituting may include substituting the platy hydrous kaolin or calcined kaolin or mixtures thereof having a median particle size d_s0 of less than 0.5 microns for the at least a portion of acicular material. For example, the hydrous kaolin may have a shape factor of at least 10. For example, the shape factor may be at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, or at least 80. According to some embodiments, the shape factor of the hydrous kaolin may range from 10 to 70, from 10 to 60, from 10 to 50, from 10 to 40, from 20 to 70, from 20 to 60, from 20 to 50, from 20 to 40, from 30 to 70, from 30 to 60, from 30 to 50, from 30 to 40, from 40 to 70, from 40 to 60, from 40 to 50, from 50 to 70, from 50 to 60, or from 60 to 70.

[0034] According to some embodiments of the method, the kaolin may include surface treated hydrous kaolin or calcined kaolin, or mixtures thereof, and the substituting may include substituting the surface treated kaolin for the at least a portion of acicular material. For example, the kaolin may include kaolin surface- treated with at least one of silanes, aminosilanes, silicates, silicone fluids, emulsions, and siloxanes. According to some embodiments, the kaolin may include kaolin surface-treated with aminosilanes.

[0035] According to some embodiments of the method, the acicular material may include fibers, and the substituting may include substituting the kaolin for at least a portion of the fibers. For example, the acicular material may include glass fibers, and the substituting may include substituting the kaolin for at least a portion of the glass fibers. According to some embodiments of the method, the acicular material may include chopped glass fibers, and the substituting may include substituting the kaolin for at least a portion of the chopped glass fibers.

[0036] According to some embodiments of the method, the polymer may include at least one of nylons, polyesters, polyimides, polyamides, aromatic polyamides, polysulfides, polyetherketones, and polycarbonates. For example, the polymer may include polyamides.

[0037] The kaolin may be prepared by light comminution (e.g., grinding and/or milling) of a coarse kaolin to give suitable delamination thereof. The comminution may be carried out by use of beads or granules of a plastic (e.g., nylon, grinding, and/or milling aid). Ceramic media such as silica and/or sand may also be used. In order to improve the dispersion of the kaolin in, for example, polymers, jet-milling and/or fluid energy milling may be used. U.S. Patent No. 6,145,765 and U.S. Patent No. 3,932,194 may provide examples of such processes. The coarse kaolin may be refined to remove impurities and improve physical properties using well-known procedures. The kaolin may be treated by a known particle size classification procedure, such as, for example, screening and/or centrifuging, to obtain particles having a desired median particle size d∞ value.

[0038] The kaolin may be surface-treated with one or more compounds, which may be selected from organic and/or inorganic compounds. These compounds may be referred to herein as surface-treatment agents. The surface treatment may generally seek to neutralize and/or reduce the activity of acid sites on the surface of the kaolin, thereby stabilizing and preferably increasing the effective lifetime of the polymer composite compositions in which the kaolins are incorporated. The neutralization of the acid sites results in a so-called passivation of the kaolin and in certain circumstances, increased hydrophobicity.

[0039] The term "surface-treatment" used herein is to be understood broadly, and is not limited to, for example, uniform coatings and/or to coatings that cover the entire surface area of a particle. Particles for which discrete regions of the surface are modified with a surface-treatment agent, and for which areas of the surface are associated with discrete molecules of the surface-treatment agent, will be

understood as being surface-modified within the terms of the present application. The compound may suitably be present in an amount sufficient to reduce the activity of and/or passivate surface acid sites of the kaolin. For example, the compound may be present in an amount ranging from 0.1 wt% to 10 wt% based on the weight of the coated particulate kaolin material. For example, the compound may be present in an amount ranging from 0.1 wt% to 3 wt%, such as, for example, from 0.5 wt%, 0.6 wt%, or 0.7 wt% and 2.0 wt% (e.g., t.5 wt %). To a certain extent, this may depend on the surface area of the kaolin but, typically, the coating level (in milligrams (mg)) of surface-treatment agent per surface area (in square meters (m²)) of dry kaolin clay may range from 0.05 mg/m² to 8 mg/m², for example, from 0.08 mg/m² to 6 mg/m², or from 0.1 mg/m² to 2 mg/m².

[0040] The particles of the kaolin usable in the present disclosure may preferably have a specific surface area (e.g., as measured by the BET liquid nitrogen absorption method ISO 5794/1) of at least 5 m²/g, for example, at least 15 m²/g, at least 20 mg²/g, at least 25 m²/g, or from 10 to 40 m²/g. [0041] The surface-treatment agent may be polymeric or non-polymeric. The surface treatment agent may include at least one functional group that can interact with a polymer or other material to be filled using the kaolin (e.g., a high shape factor hydrous kaolin or calcined kaolin or mixtures thereof). When the surface-treatment includes the use of one or more organic compounds, then the one or more organic compounds may include an organic portion and a basic portion. The organic portion of the compound may include a straight- or branched-chain alkyl group having at least three carbon atoms, such as, for example, between eight and twenty-four carbon atoms, such as, for example, a

or group. Alternatively, the organic portion may include one or more cyclic

organic groups, which may be saturated, unsaturated, or aromatic, and which may include one or more heteroatoms, such as, for example, O, N, S, and Si. The cyclic organic group may include, for example, at least one six-membered ring. The organic portion of the compound may include one or more substituent groups, such as, for example, functional groups that may cooperatively interact with a polymeric material to be filled using the surface-treated kaolin particles. The interaction may involve, for example, covalent bonding, cross-linking, hydrogen bonding, chain entanglement, or ionic interaction. Functional substituent groups may include, for example, polar or non-polar groups, and hydrophobic or hydrophilic groups.

Examples of such groups include amide or polyamide groups, which may

cooperatively interact with polyamides such as nylon, carboxyl groups, vinyl groups, which may cooperatively interact with natural or synthetic rubbers, mercapto, or other sulphur-containing groups, which may cooperatively interact with natural or synthetic rubbers, or alkylamino groups, such as ethylamino or propylamine groups. The organic compound may be monomeric or polymeric. The term "polymeric" includes homopolymers and copolymers. The organic compound may be selected from one or more saturated or unsaturated C₃-C₂₄ fatty acids, such as, for example, C₈-C₂₄, stearic acid (C₁₈) or behenic acid (C22).

[0042] The basic portion of the compound may include any group that is capable of associating with the acid sites of the kaolin particles. The basic portion may include, for example, at least one primary, secondary, or tertiary amine group. The basic portion of the organic compound may include one or more primary amine group NH₂.

[0043] The organic compound may be selected from, for example, alkyl mono-amines containing between eight and twenty-four carbon atoms in a straight- or branched-alkyl portion (e.g., hydrogenated-tallowalkyl-amine), organic

polyamines, and cyclic mono- or poly-amines including at least one cyclic ring system having at least six atoms including the ring (e.g., melamine). These compounds may carry further functional substituents on the organic portion, for example, as described above. Examples of such organic compounds include amino alcohols, such as, for example, 2-amino-2-methyl-1-propanol. .

[0044] Suitable organic amine compounds for use as surface-treatment agents may be characterized by, for example, the following formula I:

[0045] where R may be selected from straight- or branched-chain alkyl

groups and R₁ and R₂ may be selected independently from one another from

straight- or branched-chain alkyl groups. According to some embodiments, at least one of R₁ and R₂ may be H. [0046] According to some embodiments, the kaolin may be surface-treated with one or more of siloxanes, silicone fluids, oligomeric and/or polymeric emulsions, hexadecyltrimethoxysilane, and ployethyleglycol alkoxysilane. For example, siloxanes may include, but are not limited to, dimethylpolysiloxane fluids and/or hydroxyl terminated linear polydimethylsiloxane fluid. Suitable siloxanes may also include linear and cyclic siloxane oligomers, and/or polysiloxanes. Silicone fluid treatments may include, but are not limited to, wax emulsions, including natural, semi-synthetic, and synthetic waxes, for example, dispersed in a liquid carrier such as water or organic solvents, micronized waxes in powder form, and/or emulsions. Oligomeric and/or polymeric emulsions may include a high-density oxidized PE homopolymer, and/or an oxidized PE homopolymer. A suitable

hexadecyltrimethoxysilane may have hydrophobe and wetting functionality. A suitable phenyltrimethoxysilane may have hydrophobe functionality. A suitable polyethyleneglycol alkoxysilane may have wetting functionality.

[0047] According to some embodiments, the surface-treatment may include use of one or more inorganic compounds. For such embodiments, the one or more inorganic compounds may include silicon containing compounds, such as, for example, silanes, aminosilanes, and silicates. Suitable aminosilanes include, for example, trimethoxysilyl ethyl amine, triethoxysilyl ethyl amine, tripropoxysilyl ethyl amine, tributoxysilyl ethyl amine, trimethoxysilyl propyl amine, triethoxysilyl propyl amine, tripropoxysilyl propyl amine, triisopropoxysilyl propyl amine, tributoxysilyl propyl amine, trimethoxysilyl butyl amine, triethoxysilyl butyl amine, tripropoxysilyl butyl amine, tributoxysilyl butyl amine, trimethoxysilyl pentyl amine, triethoxysilyl pentyl amine, tripropoxysilyl pentyl amine, tributoxysilyl pentyl amine, trimethoxysilyl hexyl amine, triethoxysilyl hexyl amine, tripropoxysilyl hexyl amine, tributoxysilyl hexyl amine, trimethoxysilyl heptyl amine, triethoxysilyl heptyl amine, tripropoxysilyl heptyl amine, tributoxysilyl heptyl amine, trimethoxysilyl octyl amine, triethoxysilyl octyl amine, tripropoxysilyl octyl amine, tributoxysilyl octyl amine, 3- aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-Triethoxysilyl-N-(1 ,3 dimethyl-butylidene) propylamine, N-Phenyl-3-aminopropyltrimethoxysilane, and/or similar aminosilanes.

[0048] In some embodiments the one or more inorganic compounds may include diaminosilanes, such as for example, diaminosilanes containing aliphatic groups linking the silicon, first nitrogen, and second nitrogen containing from 0 to 10 carbons, diaminosilanes containing aliphatic groups linking the silicon, first nitrogen, and second nitrogen atoms containing from 0 to 5 carbons, diaminosilanes containing aliphatic groups linking the silicon, first nitrogen, and second nitrogen containing from 1 to 3 carbons, bis(alkoxysilylalkyl)amines, bis(alkylsilylalkyl)amines, diaminotrimethoxysilanes, diaminomethyldimethoxysilanes,

diaminodimethylmethoxysilanes, N-2-(aminoethyl)-3-aminopropyltrimethoxysi!ane, N-(vinylbenzyl)-2-aminoethyl-3- aminopropyltrimethoxysilane hydrochloride, N-(vinylbenzyl)-2-aminoethyl-3- aminopropyltrimethoxysilane hydrochloride, hydrolysate, and/or N-(2-aminoethyl)-3- aminopropylmethyldimethoxysilane. In some embodiments for example the diaminosilanes are represented by compounds of Formula ll(a) and Formula ll(b),

wherein each R₁ is independently selected from H and C1-C24 straight- or branched- chain alkyl or alkoxy groups, and each L is an aliphatic chain containing 0 to 10 straight- or branched carbons, and n is from 1 to 3.

[0049] In some embodiments the one or more inorganic compounds may include triaminosilanes, for example, tris(alkoxysilylalkyl)amines,

tris(alkylsilylalkyl)amines. In some embodiments the one or more inorganic compounds is an N-substituted aminosilane.

[0050] Other possible inorganics include inorganic dispersants such as phosphates, such as, for example, sodium hexametaphosphate, tetrasodium pyrophosphate, and/or sulphate-based compounds such as alum.

[0051] The surface-treated kaolin (e.g., hydrous or calcined kaolin or mixtures thereof) may be obtained by contacting a particulate kaolin having the desired shape factor with the one or more surface-treatment agents under conditions whereby the surface-treatment agent will associate with the surface of the kaolin particles. The compound may be intimately admixed with the particles of the kaolin to improve contact between the materials. Both wet and dry conditions may be used, and the surface treatment agent may be used in the form of solid particles (e.g., prills) or may be entrained in a solvent for the coating process. The coating process may be earned out at an elevated temperature.

[0052] In addition to being surface treated with a surface treatment agent, according to some embodiments, the kaolin may be subjected to a secondary treatment. The secondary treatment may include the use of one or more of the treatment agents described in relation to surface treatment, such as, for example, inorganic compounds possessing a hydrophobic portion, such as the silanes and/or aminosilanes. Other secondary treatment agents, which may be referred to herein as "secondary passivants," may include one or more of the following: antioxidants such as phenol-based antioxidants; resins such as low or medium weight epoxy resins; dispersants such as kaolin dispersants; polymers such as polyacrylates that have been hydrophobically modified; copolymers such as ethylene copolymers of polacrylic acid; and/or lubricants such as polyethylene waxes and silicone oils.

[0053] According to some embodiments, the polymer composite compositions for use in polymer articles may also include additives, such as, for example, dispersants, cross linkers, water retention aids, viscosity modifiers or thickeners, lubricity aids, antifoamers/defoamers, dry or wet rub improvement or abrasion resistance additives, optical brightening agents, whitening agents, dyes, and/or biocides.

[0054] The polymer included in the polymer composite composition may include any natural or synthetic polymer or mixture thereof. The polymer may be, for example, a thermoplastic or a thermoset. The term "polymer" used herein includes homopolymers and copolymers, as well as crosslinked and/or entangled polymers and elastomers such as natural or synthetic rubbers and mixtures thereof. Specific examples of suitable polymers include, but are not limited to, polyolefins of any density such as polyethylene and polypropylene, polycarbonate, polystyrene, polyester, acrylonitrile-butadiene-styrene copolymer, nylons, polyurethane, ethylene- vinylacetate polymers, ethylene vinyl alcohol, polyvinylidene chloride, polyethylene terephthalate, and mixtures thereof, both cross-linked or un-cross-linked.

[0055] Thermoplastic polymers are suitable for use in the production of polymer composite composition articles. Examples include polyolefins, such as, polyethylene, polypropylene, and cyclic olefin copolymers. Low density polyethylene (LDPE) may be formed, for example, using high temperature and high pressure polymerization conditions. The density is low because these polymerization conditions give rise to the formation of many branches, which may be relatively long and prevent the molecules from packing close together to form crystal structures. Hence LDPE has low crystallinity (typically below 40%), and the structure is predominantly amorphous. The density of LDPE is taken to be in the range of about 0.910 to 0.925 g/cm³. Other suitable types of polyethylene include high density polyethylene (HDPE), linear low density polyethylene (LLDPE), and ultralow density polyethylene (ULDPE). The densities of these materials may fall within the following ranges: HDPE from 0.935 to 0.960 g/cm³; LLDPE from 0.918 to 0.940 g/cm³; and ULDPE from 0.880 to 0.915 g/cm³.

[0056] According to certain embodiments, the polyamides may be selected from the group consisting of PA66, PA6, PA11, PA66/6, PA6/66, PA46, PA612, PA12, PA610, PA6I/6T, PA6I, PA9T, PADT, PAD6 (D = 2-methyl-1 ,5- diaminopentane), and PA7, and/or combinations thereof, including copolymers.

[0057] The term "precursor" is used herein in a manner understood by those skilled in the art. For example, suitable precursors may include one or more of monomers, cross-linking agents, curing systems including cross-linking agents and promoters, or any combination thereof. According to some embodiments, the kaolin material may be mixed with precursors of the polymer, and the polymer composition may be thereafter formed by curing and/or polymerizing the precursor components to form the desired polymer. [0058] In some embodiments including thermoplastic polymers, the polymer resin may be melted (or otherwise softened) prior to formation of the final article, and the polymer may not be subjected to any further chemical transformations. After formation of the final article, the polymer resin may be cooled and allowed to harden.

[0059] The thermoplastic polymer composition may be made by methods known in the art. In some embodiments, the kaolin and surface-treatment agent may be combined prior to mixing with the polymer. Similarly, certain ingredients may, if desired, be pre-mixed before addition to the compounding mixture. For example, if desired, a coupling agent may be pre-mixed with the surface-treated kaolin before addition of the kaolin to the mixture. The surface-treated kaolin and the polymer resin may be mixed together in suitable ratios to form a blend, sometimes referred to as "compounding." The polymer resin may be in a liquid form, which may enable the particles of the kaolin to be dispersed therein. Where the polymer resin is solid at ambient temperatures, the polymer resin may be melted before the compounding is performed. In some embodiments, the kaolin may be dry blended with particles of the polymer resin, and the particles may be dispersed in the resin when the melt is obtained prior to forming an article from the melt, for example, via an extruder.

[0060] In some embodiments, the polymer resin, the kaolin, and any other additives may be formed into a suitable masterbatch by the use of a suitable compounder/mixer in a manner known, and may be palletized via, for example, a single screw extruder or a twin-screw extruder, which forms strands that may be cut or broken into pellets. The compounder may have a single inlet for introducing the filler and the polymer resin together. Alternatively, separate inlets may be provided for the filler and the polymer resin. Suitable compounders are available commercially, such as, for example, from Werner & Pfleiderer. According to some embodiments, high shear compounding may be used and may result in improved dispersion of the kaolin.

[0061] According to some embodiments, the polymer composite composition may be compounded with other components or additives known in the thermoplastic polymer compounding art, such as, for example, stabilizers and/or other additives that include coupling agents, acid scavengers, and metal deactivators. Acid scavenger additives have the ability to neutralize acidic species in a formulation and may be used to improve the stability of the polymer article. Suitable acid scavengers include metallic stearates, hydrotalcite, hydrocalumite, and zinc oxide. Suitable coupling agents include silanes. The stabilizers may include one or more of thermo- oxidative stabilizers and photostabilizers. Thermo-oxidative stabilizers may include anti-oxidants and process stabilizers. Photostabilizers include UV absorbers and UV stabilizers. Some UV stabilizers, such as, for example, hindered amine light stabilizers (HALS), may also be characterized as thermo-oxidative stabilizers.

[0062] According to some embodiments, the polymer composite composition may be processed to form or to be incorporated in articles in a number of suitable ways. Such processing may include compression molding, injection molding, gas- assisted injection molding, vacuum forming, thermoforming, extrusion, blow molding, drawing, spinning, film forming, laminating, or any combination thereof. Any suitable apparatus may be used.

[0063] The polymer composite compositions disclosed herein may be used to form articles of manufacture for which desirable characteristics may include high stiffness, resistance to solvents, barrier properties, high reflectivity surfaces, heat resistance, high impact strength, and/or resistance to creep. For example, the polymer composite compositions may be used to form articles, such as, for example, aircraft parts, boat hulls, automobile parts (e.g., under-the-hood parts such as engine covers, exterior mirrors, fuel caps, etc.), bath tubs, enclosures, swimming pools, hot tubs, septic tanks, water tanks, roofing materials, pipes, claddings, watersport devices, and external door skins. Other types of articles are contemplated. Such articles may be formed using processes known to those skilled in the respective arts.

EXAMPLE 1

[0064] Example 1 in Table 1 shows fifteen polymer composite test samples and a control polymer test sample were prepared for testing Young's modulus (GPa), ultimate tensile strength (UTS) (MPa), elongation at break (mm), flexural modulus (GPa), flexural strength (MPa), and impact strength (ft-lb/in²). The test samples include nylon as the polymer and one of five sample kaolins (Kaolins A-E), each at 10 wt%, 20 wt%, and 30 wt% loading relative to the total weight of the polymer composite composition sample. Table 1 below provides characteristics of each of the test samples, including characteristics of the kaolin samples. The control sample included nylon but no kaolin.

TABLE 1

[0065] Each of the samples 1-1 to 1-15 was formed using melt mixing and injection molding. The nylon was placed in a DFA-7000 vacuum oven for four hours at 80°C. An Xplore 15 cc Twin Screw Compounder and an Xplore 10 cc Injection Moulding Machine was used to fabricate each of the samples. The melting and moid temperatures were 230°C and 85°C, respectively.

[0066] The tensile testing method was based on ASTM Standards Test Methods for Tensile Properties of Plastics (D638). An Instron 5567 Material Testing System was used to measure the test data. A 5 kN load cell was used, and the extension of the samples was set to 5mm/min. The test was set to end at a load drop of 90% of the peak load. The extensometer was set to be removed when the tensile strain hit 1.0% for 30 wt% of kaolin and 1.5% for 0%, 10 wt%, and 20 wt% loading. The flexural properties were determined using three-point bending according to ASTM.

[0067] Tables 2-7 provide the data from the testing for examples in Table 1, and Figs. 1-6 are graphs corresponding to the data shown in Tables 2-7. As can be seen from the data, the platy kaolin of Samples 1-3, 1-8, and 1-13 provided superior results at almost all loading levels, with improved results as the loading level increased.

TABLE 2

TABLE 3

EXAMPLE 2

[0068] Table 8 shows twelve PA6 nylon polymer composite test samples with kaolin and glass fiber loading. Table 8 below provides characteristics of each of the test samples, including characteristics of the kaolin samples.

TABLE 8

[0069] The PA6 nylon was Ultramid B purchased from BASF. Each sample also contained 0.2 wt% of stabilizer. The stabilizer was Lowinox HD 98 purchased from Addivant. The polymer was dried for three hours at 80°C in a DFA-700 vacuum oven (<0.33 bar). The test samples include polymer and one of five different kaolins (Kaolin E, Kaolin C2, Kaolin B2, Kaolin C2, and Kaolin C3) and glass fibers loaded at the shown wt% relative to the total weight of the polymer composite composition sample. The glass fibers were Advantex glass fibers with 10 micrometer diameter purchased from Owens Corning and chopped down to 1/8 inch average size. Kaolin E was a calcined kaolin. Kaolin C2 was a hydrous kaolin treated with a silane.

Kaolin A2 was a calcined kaolin treated with a silane. Kaolin B2 was a hydrous kaolin treated with a silane. Kaolin C3 was hydrous kaolin treated with two silanes. In the silane treatment, the appropriate silane dosage was added to kaolin and mixed. The treated powder was then collected.

[0070] The ultimate tensile strength (UTS) (MPa), tensile strain at yield, tensile modulus (MPa), flex modulus (MPa), flex strength at break (MPa), and impact strength notched (kJ/m²) were measured for these samples. Average reported values and standards of deviation are for 4 or 5 experiments each.

[0071] Each of the samples 2-1 to 2-12 was formed using melt mixing and injection molding. An Xplore 15 cc Twin Screw Compounder and an Xplore 10 cc Injection Molding machine was used to fabricate each of the samples. The compounding temperature was set at 250 "C. Compounding occurred at 100 rpm for 3 minutes prior to extrusion and injection molding. Injection molding was performed in an injection cycle to 8-12-12 bar for 5 seconds each. The melting temperatures was maintained at 230 °C. The mold temperature was 85 ^*C. The molds were set to a temperature of 60 "C with the transfer gun at a temperature of 245 "C. The samples were stored in a sealed plastic bag and tested after 48 hours.

[0072] The tensile testing method was based on ASTM Standards Test Methods for Tensile Properties of Plastics (D638). An Instron 5567 Material Testing System was used to measure the test data. A 5 kN load cell was used, and the extension of the samples was set to 5mm/min. The test was set to end at a load drop of 90% of the peak load. The extensometer was set to be removed when the tensile strain hit 1.0% for 30 wt% of kaolin and 1.5% for 0%, 10 wt%, and 20 wt% loading. The flexural properties were determined using three-point bending according to ASTM or ISO 178. The Charpy notched impact strength was measured based on ISO 179.

[0073] Polymer's ability to withstand a given load at elevated temperatures is expressed in terms of heat deflection temperature. This test was performed using a 1.8 MPa load under ASTM D648 analogous to ISO 75 method A.

[0074] Tables 9 and 10 below provide the data from the testing, and Figs. 7- 11 are graphs corresponding to the data shown in Tables 9 and 10.

TABLE 9

[0076] Overall, flexural modulus is significantly improved with addition of treated clays in the systems, see Figs. 7 and 8. The >50% increase in flexural modulus with Kaolin C3 and >10% increase with Kaolin C2 compared to the current industry standard calcined kaolins (Kaolin E). Both Kaolin C3 and C2 are hyper platey surface treated hydrous clays with distinct silane treatments. 50%

replacement of GF with surface treated kaolins contributes to a substantial increase in flexural strength. This indicates that stiffness of the material is increased with addition of Kaolin C3. The influence of kaolin particle morphology is evident in straight mineral containing systems.

[0077] After 50% replacement of glass fiber, Kaolin C2 and Kaolin C3 containing samples showed comparable tensile strength results to 100% GF filled PA6. See Figs. 9 and 10. The replacement of 50% glass fibers with surface treated hydrous platey kaolins would give significant cost savings. Kaolin C2, Kaolin C3 and Kaolin B2 products demonstrated good reinforcement and overall balance of properties at 50% replacement of GF in the PA6 resin. Kaolin A2+Kaolin C2 blend showed improvement in impact strength and marginal decrease in flexural and tensile properties compared to the Kaolin A2 only and Kaolin C2 only straight mineral systems.

[0078] The systems with higher stiffness showed lower impact strength, see Fig. 11. Kaolin C3/GF and Kaolin A2/GF 15/15 systems showed substantial improvement in the impact strength results compared to the Kaolin E/GF 15/15 system containing standard mineral filler. Kaolin A2+Kaolin C2 straight mineral containing samples showed overall, good balance of flexural strength, modulus and impact strength are achieved by blending surface treated hydrous hyper platey kaolin with blocky calcined kaolin.

[0079] Additionally further samples were prepared according to the same methods as above, but with different glass fiber content as shown in Table 11. A polymer's ability to withstand a given load at elevated temperatures is expressed in terms of heat deflection temperature. The heat deflection temperature of the polymer compositions in Table 11 are reported there. This test was performed using a 1.8 MPa load under ASTM D648 analogous to ISO 75 method A.

[0080] Typically, heat deflection temperature of Nylon PA6 without any reinforcing fillers is approximately 60^*C under 1.8 MPa load. Samples comprising hyper platy kaolins C3 and C2 showed relatively higher heat deflection temperature than industry standard calcined kaolin E. See. Fig. 12.

[0081] Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. It is intended that the specification and examples be considered as exemplary only.

Claims

WHAT IS CLAIMED IS:

1. A polymer composite composition for manufacturing an article, the composition comprising:

kaolin comprising hydrous kaolin, calcined kaolin, or mixtures thereof;

an acicular material; and

a polymer comprising at least one of nylons, polyesters, polyimides, polyamides, aromatic polyamides, polysulfides, polyetherketones, and

polycarbonates,

wherein the kaolin, acicular material, and polymer are combined to form the polymer composite composition.

2. The composition of claim 1, wherein the hydrous kaolin comprises platy hydrous kaolin.

3. The composition of claim 1 , wherein the hydrous kaolin has a shape factor of at least 10.

4. The composition of claim 1 , wherein the hydrous kaolin has a shape factor of at least 30.

5. The composition of claim 1, wherein the hydrous kaolin has a shape factor of at least 60.

6. The composition of claim 1 , wherein the kaolin comprises surface-treated kaolin.

7. The composition of claim 1 , wherein the kaolin comprises kaolin surface- treated with at least one of silanes, aminosilanes, silicates, silicone fluids, emulsions, and siloxanes.

8. The composition of claim 1 , wherein the kaolin comprises kaolin surface- treated with aminosilanes.

9. The composition of claim 1 , wherein the acicular material comprises fiber

10. The composition of claim 1, wherein the acicular material comprises chopped fiber.

11. The composition of claim 1 , wherein the acicular material comprises glass fiber or wollastonite.

12. The composition of claim 1, wherein the acicular material comprises chopped glass fiber.

13. The composition of claim 1, wherein the composition comprises at least 10 wt% kaolin relative to the total weight of the composition.

14. The composition of claim 1, wherein the composition comprises at least 20 wt% kaolin relative to the total weight of the composition.

15. The composition of claim 1, wherein the composition comprises at least 30 wt% kaolin relative to the total weight of the composition.

16. The composition of claim 1 , wherein the median particle size d₆₀ of the kaolin is less than or equal to 2 microns.

17. The composition of claim 1 , wherein the median particle size d₅₀ of the kaolin is less than or equal to 1.5 microns.

18. The composition of claim 1, wherein the median particle size dso of the kaolin is less than or equal to 1.0 micron.

19. The composition of claim 1 , wherein the median particle size dso of the kaolin is less than or equal to 0.5 microns.

20. The composition of claim 1 , wherein the median particle size dso of the kaolin is less than or equal to 0.5 microns, and the kaolin comprises kaolin surface- treated with aminosilanes.

21. An article comprising the polymer composite composition of claim 1, wherein the article comprising the polymer composite composition including the kaolin has a flexural modulus higher than the article comprising the polymer composite composition devoid of the kaolin.

22. An article comprising the polymer composite composition of claim 1 , wherein the article comprising the polymer composite composition including the kaolin has a flexural modulus at least 10 higher than the article comprising the polymer composite composition devoid of the kaolin.

23. An article comprising the polymer composite composition of claim 1 , wherein the article comprising the polymer composite composition including the kaolin has a flexural modulus at least 25% higher than the article comprising the polymer composite composition devoid of the kaolin.

24. A method of reducing acicular material in a polymer composite

composition comprising the acicular material and a polymer while maintaining a flexural modulus of an article comprising the polymer composite composition, the method comprising:

substituting kaolin comprising hydrous kaolin, platy hydrous kaolin, calcined kaolin, or mixtures thereof for at least a portion of the acicular material in the polymer composite composition.

25. The method of claim 24, wherein the substituting comprises substituting the kaolin for the at least a portion of acicular material at least a 1 :1 ratio of kaolin to acicular material based on weight.

26. The method of claim 24, wherein the kaolin comprises kaolin having a median particle size d₅o of less than 0.5 microns, and the substituting comprises substituting kaolin having a median particle size dso of less than 0.5 microns for the at least a portion of acicular material.

27. The method of claim 26, wherein the platy hydrous kaolin has a shape factor of at least 10.

28. The method of claim 26, wherein the platy hydrous kaolin has a shape factor of at least 30.

29. The method of claim 26, wherein the platy hydrous kaolin has a shape factor of at least 60.

30. The method of claim 24, wherein the kaolin comprises surface-treated kaolin, and the substituting comprises substituting the surface-treated kaolin for the at least a portion of acicular material.

31. The method of claim 30, wherein the surface-treated kaolin is surface- treated with at least one of silanes, aminosilanes, silicates, silicone fluids, emulsions, and siloxanes.

32. The method of claim 30, wherein the surface-treated kaolin is surface- treated with aminosilanes.

33. The method of claim 24, wherein the acicular material comprises fibers, and the substituting comprises substituting the kaolin for at least a portion of the fibers.

34. The method of claim 24, wherein the acicular material comprises glass fibers, and the substituting comprises substituting the kaolin for at least a portion of the glass fibers.

35. The method of claim 24, wherein the acicular material comprises chopped glass fibers, and the substituting comprises substituting the kaolin for at least a portion of the chopped glass fibers.

36. The method of claim 24, wherein the polymer comprises at least one of nylons, polyesters, polyimides, polyamides, aromatic polyamides, polysulfides, polyetherketones, and polycarbonates.

37. The composition of claim 1 , wherein the composition has a heat deflection temperature higher than 100 'C under a 1.8 MPa load under ASTM D648.

38. The method of claim 32, wherein the aminosilane is a diaminosilane.