MXPA98002269A

MXPA98002269A - Improved process to produce thermoplastic resins manufactured according to specification

Info

Publication number: MXPA98002269A
Application number: MXPA/A/1998/002269A
Authority: MX
Inventors: M Hurley James; B Brian Bernd; E Tuttle Mary; Popovski Blagojce
Original assignee: Basf Corporation
Priority date: 1997-06-30
Filing date: 1998-03-23
Publication date: 1999-02-24

Abstract

The present invention describes a thermoplastic personality resin having a thermoplastic resin body and a thermoplastic resin body coating. The coating contains a hydrophobic resin component and at least one additive. The hydrophobic resin component of the coating has an initiation temperature for its melt processing range below the initiation temperature for the melt processing range of the thermoplastic resin body. The custom thermoplastic resins of the invention can be produced more efficiently than conventional custom thermoplastic resins, while the custom thermoplastic resins of the invention can be used in the same methods as conventional materials to produce useful articles.

Description

IMPROVED PROCESS FOR PRODUCING ICAS THERMOPLAS RESINS MANUFACTURED ACCORDING TO SPECIFICATIONS FIELD OF THE INVENTION The present invention relates to colored thermoplastic resins which are useful for molding articles. In particular, the invention relates to thermoplastic resins manufactured according to specifications, having a thermoplastic resin body, or a base resin, coated with a second thermoplastic composition of the lower melting point. The second thermoplastic composition consists of at least one additive, preferably a dye or pigment and particularly preferably an additive not present in the first thermoplastic composition. In a preferred embodiment, the second thermoplastic composition contains as an additive a dispersed pigment. The composite thermoplastic resin is formed into an article by melting and mixing together the first and second thermoplastic compositions and extruding, molding or otherwise shaping the combination into the article.

BACKGROUND AND SUMMARY OF THE INVENTION Thermoplastic resins are formed in multiple kinds of articles, for example, by extrusion molding, thermoforming and compression processes. Thermoplastic resins are usually compounded and manufactured as granules or powders that can be easily shipped and can be easily and conveniently handled during the formation of the desired items or can be stored for further processing. It is more economical to manufacture the thermoplastic resins as granules in a continuous extrusion process in which the granules are compounded to meet the requirements of multiple uses. However, it is usually the case that a thermoplastic resin must be specially formulated or customized for a specific use or application, such as coloration processes obtainable when molding, for example, including special additives for this use, such as pigments to achieve a specific color or a stabilizer package that meets the specific use requirements. In particular, the thermoplastic resins can be customized to include certain pigments and / or dyes. It is often desirable that the manufactured item have a specific color. A specific color can, for example, improve the aesthetic appearance of the article or can even serve to help identify the particular brand or manufacturer. However, color customization or additive packages of thermoplastic resins can present problems. Although general purpose thermoplastic resin, or base resin, can be produced by continuous extrusion operations, colored thermoplastic resins or thermoplastic resins with special additive packages are usually required in much smaller quantities that are relatively expensive in their production. Manufacturing, especially post-production cleaning, is an extremely intense task. The processing equipment (such as mixers, feeders, extruders and granulation equipment) must be perfectly cleaned after each specific color or customized mix to avoid contamination of the thermoplastic resins that will later be produced in the equipment. The cleaning process requires a significant period of interruption in the equipment during which no material must be manufactured, increasing the manufacturing costs of the specialized product. In an alternative mode, the colored articles have been produced by dry blending the colorless thermoplastic resin with a color concentrate (also known as the color masterbatch) which is known in the art as a "salt and pepper mixture". The thermoplastic resin and color concentrate used for these combinations are usually granules or pieces of similar size. The color concentrate is usually a minor amount by weight of the mixture, usually only up to about 5% by weight, and often much less. The salt and pepper mixture is then introduced directly to the molding or forming equipment used to produce the final article. The melt blending of the uncolored resin and the color concentrate should be carried out in the molding or forming equipment. However, this process may result in color variations from one piece to another, or even in areas within the same piece, due to incomplete mixing, particularly for low mixing ratios of the color concentrate. Segregation of particular additives during packaging and transportation must also be experienced by dry blends and contributes to the lack of homogeneity in the final shaped articles. In a method related to the use of a salt and pepper mixture it is possible to introduce plates and liquid colors into the nozzle of an injection molding extruder or other forming equipment. This method also has some disadvantages. First of all, it is possible that the manufacturer needs complex dosing equipment to produce a uniform coloration. Secondly, this method is similar to the salt and pepper method in that the dye material and the colorless resin are introduced practically separately, remaining at the expense of perfect mixing in the forming equipment before the article is finally formed. Incomplete mixing and color variations can be easy. Gose et al., In U.S. Patent No. 5,443,910 and related patents, disclose the application of certain processing additives, stabilization or other functional polymeric additives to the polymer particles by spraying the particles with an aqueous emulsion of the polymeric additive. The emulsion includes an emulsifiable wax (with acid function), surfactant, a base the additive and water. This method of customizing thermoplastic resins, however, has some disadvantages. First, the inclusion of a base compound in the applied material may give rise to undesired coloration or color deviations, for example, Goce et al., Indicate problems when potassium hydroxide or sodium hydroxide is used. It is also well known that in some systems discoloration can occur from amines. Secondly, the water of the emulsion or the combination of water and base presents problems for hydrophilic resins. In addition, it may sometimes be desirable to exclude the surfactants from the thermoplastic resin. Finally, the method of application of the emulsion has disadvantages that are inherent in the process, for example, that the applied layer of the emulsion must be dried and the emulsion stored and used under carefully maintained conditions to avoid destabilization and separation. Sharma, in U.S. Patent No. 5,300,256 and related patents, also disclose the application of an additive to a polymeric particle from an aqueous medium. Sharma describes the handling and storage problems described by Gose and provides a solid additive system that can be dispersed in water just before application. The polymeric additives used by Sharma must be melted at a temperature not higher than 100 ° C and may include hydrophilic polymers such as low molecular weight polyolefins with carboxylic moieties. The additives again contain water and are further diluted with water and applied as an aqueous emulsion, still with concomitant problems such as those already mentioned. It is also known to prepare color concentrates by a method in which a mixture of pigment, low molecular weight polyethylene wax and thermoplastic polyolefin granules are combined together. The pigment and the wax are included in relatively high levels, for example, about 40% by weight of the mixture. The wax that disperses the pigment forms a layer on the polymer granules. This masterbatch is combined with unmodified basic polyolefins to form a "salt and pepper" mixture. The high pigment loading and dispersing wax are required in the masterbatch to achieve the desired final pigment loading in the salt and pepper mixture. These mixtures containing the masterbatch present the same problems already described. further, the relatively thick coating of the wax on the granules is undesirable for the reason that these thick coatings tend to split and flake easily, which could give rise to the segregation and inhomogeneity in the molded articles, as well as problems of powders in production. In this way, it would be desirable to provide a custom thermoplastic resin that overcomes the disadvantages of those produced by the methods already described. We have now discovered a novel method for preparing custom thermoplastic resins in which the pieces, usually thermoplastic resin granules, are coated with a coating that includes a hydrophobic resin component and at least one additive. The hudrophobic thermoplastic coating layer consists of a hydrophobic resin composition having a melting point, softening point or glass transition temperature lower than the melting point, softening point or glass transition temperature of the thermoplastic resin body. The aforementioned melting point, softening point or glass transition temperature (or other temperature or temperature range where the resin begins to soften or flow), of a specific resin or resin composition may be, for convenience, called the initiation temperature of the fusion processing range. The hydrophobic resin component or coating has a lower initiation temperature, for its melt processing temperature, than the initiation temperature for the melt processing range of the thermoplastic resin body. Those skilled in the art will appreciate that the term "initiation temperature for the range of the melt processing" is used herein for convenience, and may indicate a single different temperature or a range of temperatures. In relation to range differences, one can use the difference of the upper, lower or average temperature within a range; the preferred term employs the most significant temperature separation in the application under consideration. In a preferred embodiment, the coating containing the hydrophobic resin component and at least one additive is a colored concentrate. In a process for producing the custom thermoplastic resins of the invention, the thermoplastic resin body is contacted with the coating at a temperature at which the hydrophobic resin component is a melt. The coated resin parts are cooled to solidify the coating in a layer on the thermoplastic resin body or part. In a preferred embodiment a substantially uniform thickness of an outer layer of the custom hydrophobic resin component is applied. Coated resin pieces or granules are easily handled and can be formed into articles using the same processes and in the same way as the resin granules that have had the color or other additives mixed in an integral manner. The color concentrate or other custom coating composition is covered over the resin after the resin piece has been formed. The custom thermoplastic resins of the invention in this way can be produced in an easy to clean equipment and do not require a time to stop the equipment used to manufacture the thermoplastic resin body, resulting in a much more versatile and economical process. In addition, because each granule or other body of the thermoplastic resin is in intimate contact with the pigment or additive necessary to produce the desired custom resin, defects such as inhomogeneity are avoided, which is especially evident when color is included. In addition, the surfactants, water, amines and resins with hydrophilic functionality used in the prior art compositions are no longer necessary for the coatings of the present invention. In particular, the present invention provides a custom thermoplastic resin having a thermoplastic resin body and an outer layer of the thermoplastic coating that covers at least a body part of at least one hydrophobic resin component and therefore an additive component. It is particularly preferred that the additive be a pigment.

DETAILED DESCRIPTION Customized thermoplastic resins of the invention have a thermoplastic resin body and an outer layer of thermoplastic coating that at least partially covers the body. The coating consists of a hydrophobic thermoplastic resin component having an initiation temperature for its melt processing range that is lower than the melt process range initiation temperature of the thermoplastic resin body. The coating contains at least one additive and preferably contains at least one colorant or pigment as the additive or as one of a plurality of additives. The thermoplastic resin body is preferably a granulate. Thermoplastic resins are custom-made as granulates for further processing in the desired article. The term "granulate" is understood and used herein to comprehend various geometric shapes, such as square shapes, trapezoids, cylinders, lenticulars, cylinders with diagonal faces, flakes, bits and substantially spherical shapes that includes a powder particle or a Larger size sphere. Although thermoplastic resins are often sold as granules, the resin can be in any shape by size suitable for use in the equipment that is used to form the final article. The thermoplastic resin body can comprise almost any suitable thermoplastic resin to be formed into articles by thermal processes, molding, extrusion or other of these processes that can be employed in the methods of the invention, with the proviso that the thermoplastic resin of the The resin body must have an initiation temperature for its melting process range greater than the initiation temperature of the melt processing range of the hydrophobic resin component of the outer coating layer. For example, and without limitation, it is possible to use advantageously the following thermoplastic materials: acrylonitrile-butadiene-styrene (ABS), acetal resins such as polyoxymethylene, acrylics, acrylonitrile (AN), allyl resins, cellulosics, epoxies, polyarylether ketones, polyether ether ketones (PEEK), phenolics, polyamides (nylon), including polyamide-6, polyamide-6, 6, polyamide-6, 10 and others; polyimides, polyamide-imide resins, polyolefins (TPO), including homopolymers and copolymers of polyethylene, polypropylene and polybutylene; polycarbonates; polyesters, including polyalkylene terephthalates such as polybutylene terephthalate (PBT) and polyethylene terephthalate (PET); polyimides and polyether imides; polyphenylene oxide; polyarylene sulfites, such as polyphenylene sulfite; polyarylene sulfides such as polyphenylene sulfide; polyvinyl resins, including polystyrene (PS) and styrene copolymers such as styrene-acrylonitrile copolymer (SAN) and acrylic-styrene-acrylonitrile copolymer (ASA), polyvinyl polymers including polyvinyl chloride (PVC) and polyvinyl phenylene chloride; polyurethanes (TPU) and polysulfones, including polyaryl ether sulfones, polyether sulfones and polyphenyl sulfones. Mixtures of block copolymers of 2 or more resins can also be used. Preferred materials for the thermoplastic resin body include polyesters, polyamides, polyolefins, polystyrenes and polystyrene copolymers, polyacetals, polycarbonates, acrylics, polyether ether ketones and mixtures thereof. Polyesters, polyamides, polystyrenes and polystyrene copolymers and mixtures thereof are especially preferred. The thermoplastic resin body of the present custom thermoplastic resins may also contain a fibrous material. These fibers can be included as reinforcing agents. Useful fibers include, without limitation, glass fibers, carbon fibers and graphite, polymeric fibers including aramid fibers, boron filaments, ceramic fibers, metal fibers, asbestos fibers, beryllium fibers, silica fibers, silicon carbide fibers and others. The fibers can be conductive and such conductive fibers, for example carbon fibers or conductive metal fibers, can be used to produce articles for conductive or static charge dissipation applications or the EMI protective cover. Among these, glass fibers, carbon fibers and aramid fibers are preferred. Methods of preparing the thermoplastic resins that include these fibers are well known in the art. In one method, bundles of cut glass fibers are fed into the melting zone of the extruder that is used to form the thermoplastic resin body, for example, by introducing the bundle or bundle of fibers through a feeder port. The custom coating or outer layer covers at least part of the thermoplastic resin body, in a preferred embodiment, the thermoplastic resin body is substantially encapsulated by the coating. By "substantially encapsulated" we understand that at least about three quarters of the surface of the thermoplastic resin body is coated, and preferably at least about nine tenths of the resin body is coated. It is particularly preferred that the coating covers substantially the entire resin body. The coating of the custom thermoplastic resin has a thickness that will give rise to the desired weight ratio of the coating composition to the composition of the thermoplastic resin body when the two are melt combined during the formation of the final article. The weight ratio of the coating to the thermoplastic resin may, in general, be in the range of at least about 0.1% by weight and up to about 10% by weight, based on the weight of the custom thermoplastic resin. It is preferred that the coating be at least about 0.5% by weight and up to about 5% by weight, based on the weight of the custom thermoplastic resin.

In this way, the thickness of the coating will depend on factors such as the surface area of the thermoplastic resin body that is coated and the concentration of the additive and additives in the coating compared to the desired concentration in the final mixture of the resin body and the coating. For a common cylindrical granule, the coating can be up to an average of about 300 microns thick. In a preferred embodiment, the average thickness of the coating for these granules can be at least about 10 microns and up to about 200 microns. The coating comprises a hydrophobic resin component and at least one additive component. When the thermoplastic resin body contains a water-sensitive material, such as a polyamide, it is preferred that the coating contains a hydrophobic resin component as its polymer component. It is contemplated that a hydrophobic polymer-based coating, such as a wax-containing coating, will slow down or prevent the reabsorption of water in a hydroscopic resin body [sic]. Examples of suitable materials for the hydrophobic resin component include, without limitation, waxes and wax mixtures. Waxes are usually defined as materials that are solid at room temperature, have relatively low melting points and can soften when heated and harden upon cooling. The waxes of the present invention are insoluble in water and have groups of non-acidic or amino groups. Useful waxes include, without limitation, natural waxes such as animal waxes, vegetable waxes, mineral waxes and petroleum waxes, as well as synthetic waxes. Preferred among these are hydrocarbon waxes, such as paraffin waxes; polyalkylene homopolymers and copolymers, especially polyethylene, polypropylene and copolymers of alkenes having from 2 to 10 carbon atoms, particularly copolymers of ethylene with alkenes having from 3 to 10 carbon atoms, especially copolymers with propylene or butylene; microcrystalline waxes; carnauba waxes; ozokerite or lignite wax; Fischer-Tropsch waxes; acid grades, fatty acid derivatives, especially those having about 12 to 18 carbon atoms, including stearic acid, palmitic acid, lauric acid, myristic acid, oleic acid, linoleic acid and tallow oil fatty acids, these derivatives includes fatty amides and fatty acid esters; hydrogenated oils such as hydrogenated castor oil; polyethers including polyalkylene glycols such as polyethylene glycol, polypropylene glycol and block copolymers thereof; polytetrahydrofuran and mixtures thereof. Especially preferred are polyethylene waxes which contain molecular weights preferably at least about 2000 and preferably below about 12,000; carnauba waxes; esters of fatty acids; lignite waxes and mixtures thereof. Other suitable hydrophobic resin materials include polystyrenes and polystyrene derivatives, polyvinyl polymers including chlorinated polyvinyl polymers such as polyvinyl chloride and mixtures thereof. The coating includes at least one additive. Examples of suitable additives include, without limitation, plasticisers, thixotropes, optical brighteners, antioxidants, UV haulers, hindered amine light stabilizers, hindered amide light stabilizers, thermal stabilizers, flame retardants, pigments, dyes, conductive materials, non-fibrous reinforcers and particulate fillers such as talcum, shock modifiers such as ionomers, maleinized elastomers and natural and synthetic rubber particles, processing aids such as lubricants, mold releasing agents and slip agents, fragrances, antifoaming agents, antioxtants, antistatic agents , antimicrobials, biocides and others. Surfactants and acids or bases that are used to salt ionic resins or polymers are not considered additives within the scope of the invention.

In a preferred embodiment, the coating contains at least one pigment or dye. Preferably, the pigment is present in an amount of up to about 8% by weight and, especially, up to about 4% by weight, based on the weight of the custom thermoplastic resin. Suitable pigments are black, white or colored pigments, as well as extender pigments. Examples of useful pigments include, without limitation, titanium dioxide, zinc oxide, zinc sulphide, barium sulfate, aluminum silicate, calcium silicate, carbon black, iron oxide black, black copper chromite, oxides yellow iron, red iron oxide, brown iron oxide, ocher, sienna, dark ocher, hematite, limonite, mixed iron oxides, chromium oxide, Prussian blue (ammonium ferrocyanide), chrome green, chrome yellow , manganese violet, cobalt phosphate, lithium and cobalt phosphate, groceries, blue and green copper phthalocyanines, azo metallized and non-metallized red, gold, red and purple quinacridones, yellow mono- and diaryluride, naphthol red, pyrrolo-pyrrole , anthraquinones, thioindigo, flavantrone and other tub pigments, pigments based on benzidimidazolone, dioxazine, perylenes, carbazole violet, perinone, isoindoline and others.

The dyes can be used in place of a pigment or in addition to the pigment. For example, it is possible to use a dye to produce a brighter color than would otherwise be obtained with a composition containing only pigments. Examples of useful colorants include, without limitation, azo dyes, such as Solvent Yellow 14 and Metanil Yellow; Anthraquinone dyes such as Solvent Red 111, Solvent Blue 56 and Solvent Green 3; xanthan dyes, such as Rhodamine B, Sulfo Rhodamine, Sovent Green 4, Acid Red 52, Basic Red 1 and Sovent Orange 63; azine dyes such as indulin and nigrosines; fluorescent dyes, Brilliant Sulfoflavine (Acid Yellow 7), Sovent Orange 60 (a perinone dye), basic triphenyl dyes, such as methyl violets and Victoria Blue B and quinoline yellows. Conductive materials include conductive pigments, such as certain grades of carbon black and graphite. Carbon black can function as a conductive material and as a colorant. These conductive materials can be incorporated into the coating composition according to the normal methods for incorporating fillers or pigments, which will now generally be described by making specific references to the pigments.

The pigment can be dispersed in the carrier, which is preferably the hydrophobic resin component, by a two-step process. In a first step, agglomerates of the pigment are broken into smaller particles. In a second step, the air at the surface of the pigment particles is displaced with resin to "soak" the pigment, thereby fully developing its hue and color intensity. A method for dispersing the pigment in the carrier resin or in the hudifiphobic resin component is to first spin the pigment with the granules of the resin in a drum and then obtain an intimate mixture by processing the mixture in a roller mill, a Banbury mixer, Intensive mixer or single or double helix extruder. When the hydrophobic resin component is part of a color concentrate, it is advantageously selected for its ability to disperse a high pigment load and for its easy handling. The dispersed colorant may be a conventional color concentrate or a light color. If a liquid color is used, it should be used at a fairly low level to be encapsulated by the polymeric component so that the coating is solid at ambient temperatures. Conventional color concentrates may include one or more thermoplastic resins and one or more pigments. Examples of suitable thermoplastic resins include, without limitation, waxes, as the examples mentioned in the above; polyolefins, polystyrenes and polyvinyl chloride resins. It is preferred that the thermoplastic resin of the color concentrate consists of or comprises a part of the hydrophobic resin component of the coating. The pigment may be any of those known in the art, such as those mentioned above, and mixtures of pigments. The conventional color concentrates may be in the form of granules, cubes, beads, wafers or microspheres. The color concentrates can have a pigment loading from about 10% by weight to about 80% by weight, usually from about 30% by weight to about 60% by weight, based on the weight of the pigment. concentrated color. It is preferred that the color concentrate has a pigment loading of up to about 80% by weight, and preferably at least about 50% by weight. The concentration of the pigment will vary depending on the selection of the pigment and the carrier. Liquid colors usually have pigment loads from about 10% to up to about 80%. It is particularly preferred that the coating contains at least one color concentrate. The color concentrate can be prepared according to known means, with at least one pigment and optionally with additional additives as antioxidants, and can be used as the coating during the preparation of the custom resins of the invention. In an alternative mode, two or more color concentrates can be combined to obtain the desired color and can be applied as the coating of the invention. Colored concentrates are commercially available from several companies, including ReedSpectru, Holden, MA; Unifor Color Company, Holland, MI; Americhem Inc., Cuyahoga Falls, OH; and Holland Colors Americas Inc., Richmond, IN. The thermoplastic resin body may also include one or more additives. When the same additive is present in the composition of the thermoplastic resin body and in the thermoplastic coating layer, then the composition of the layer can be used to increase the amount of the additive to customize the concentration of this additive over that of the base resin . When the additive that is present in the hydrophobic resin component is not present in the thermoplastic resin body composition, then the addition of a layer of the hydrophobic resin component can be used to customize the granulate including an additive not found in the resin of the body. The coating preferably includes at least one additive that is not included in the body of the thermoplastic resin. In a particularly preferred embodiment, the thermoplastic resin body is non-pigmented-that is, it contains substantially no pigment or dye-and the coating contains at least one pigment or dye. The hydrophobic resin component must have an initiation temperature for its melt processing range that is below the melt processing range initiation temperature of the thermoplastic resin body. In this way, the melt of the coating containing the hydrophobic resin component can be applied to the first thermoplastic resin composition while the latter is solid or substantially solid. The initiation temperature of the melt processing range of the hydrophobic resin component is preferably above about 20 ° C and more preferably is above about 60 ° C and, even more preferably, is at least about 80 ° C. ° C. The hydrophobic resin component preferably has an initiation temperature for its melt processing range of at least about 20 ° C below and, even more preferably at least about 40 ° C below the initiation temperature for the range of the fusion process of the thermoplastic resin body. If the custom thermoplastic resin granules are to be dried using a dryer, then the range of the melt processing of the hydrophobic resin component is preferably above the dryer temperature. In a preferred embodiment, the coating encapsulates the thermoplastic resin granules and the hydrophobic resin component is chosen to prevent or slow down the absorption of water so that a drying step before the formation of the desired article is unnecessary is unnecessary. The initiation temperature of the melt processing range of the coating composition containing the hydrophobic resin component should be below the melt initiation temperature of the thermoplastic body composition process. A lower initiation temperature of the melt process range can be obtained using a different kind of polymeric material, for example, using a nylon composition for the thermoplastic resin body composition and a polyethylene composition for coating composition or using resins with the same class of polymeric material that have different processing temperature ranges due to different molecular weights, plasticization with lower melting point materials or using different monomers during resin synthesis that tend to reduce their processing temperature range . For example, the composition of the thermoplastic resin body may contain a polyolefin resin and the coating composition may also contain a polyolefin, but with the polyolefin of the coating having an initiation temperature lower than the melt processing range. The thermoplastic resin or the resins that are included in the hydrophobic resin component preferably have no detrimental effect on any of the resins of the thermoplastic resin body composition. For example, the hydrophobic resin component should not contain resin that is incompatible with a resin of the thermoplastic resin body composition at the expected processing temperatures at which the custom resin will be used to form the final article. An example of a damaging interaction would result from a combination of polyvinyl chloride and nylon in which the production of HCl from the PVC during processing would cause the degradation or discoloration of the nylon. A second example of an undesirable interaction would be a transesterification or transamidation between a nylon and a polyester. Another example of an undesirable interaction would be the stratification of two resins during the step of forming the final article due to incompatibility. Although the use of a combination of resins having these interactions is not preferred, it is still possible to use an otherwise undesirable resin in the coating composition in small amounts, such as less than about 5% by weight and especially less than about 3% by weight, based on the total weight of the custom thermoplastic resin. For convenience, but not limitation, custom thermoplastic resins of the present invention will, in general, be described in terms of a granular form, although other forms as contemplated are contemplated. In a preferred process for producing the custom thermoplastic resin of the invention, the unmodified thermoplastic resin and, optionally, one or more additives, such as UV stabilizers or processing aids, are charged to a hopper and fed to a Single-screw or twin-screw extruder. A hot feed of glass or mineral reinforcements and, optionally, shock modifiers can be introduced into the melting zone of the extruder, if desired.The extruded product from the nozzle can be cooled, for example, in a water bath. water and then granulate according to the methods customary to produce the thermoplastic resin body In the case of a thermoplastic resin that is susceptible to yellowing, the extruded product is preferably rapidly cooled to a temperature below the melting point range, preferably at a temperature of about 150 ° C below and, preferably, at a temperature of not less than about 60 ° C. In general, coating compositions having low melt processing ranges are preferred for thermoplastic resins that tend to yellow. The granules based on hydroscopic thermoplastic materials [sic] must be dried before being coated. After forming, the granules can then be coated by the different methods. In one method, the granules are placed in a container with a coating composition while the granulate is still at a temperature above the initiation temperature of the melt processing range of the coating composition. In this case, the composition of the coating may already be melted or it may be melted by the heat of the granulates or by heat applied externally to the container. For example, without limitation, the coating can be introduced into the container as a powder when the container is to be melted. It is particularly preferred if the coating composition is not melted before being brought into contact with the granulate, that the coating composition has an initiation temperature for its melt processing range which is below the temperature of the granulate in the container, which will usually be above 60 ° C and up to about 150 ° C. The contents of the container are mixed, for example, by drum rotation or with a blade blade or a propeller blade. Additional heat can be applied to the container when necessary to obtain the desired coating of the granulate with the coating composition. The coated granulate is then cooled using a cooling jacket with agitation of the contents of the container, direct application of cooling air to the granulate in the container or to the granulate after it leaves the container or by contacting the granulate with a non-reactive refrigerant such as it can be liquid nitrogen or dry ice. It is possible to introduce the granulate in a drum or stir it during cooling so that it does not agglutinate. The granulate is preferably cooled to a temperature at which the coating hardens to easily remove the granulate from the container and can be further cooled when necessary before packaging. In a second method for applying the coating to the granulate, the granulate, after leaving the granulator and while it is still hot, is transported to an area where the coating composition is applied as a melt (ie without solvent). The composition of the coating can be applied by spraying, as long as the composition is of a viscosity suitable for the spray equipment or can be applied by powder coating methods. The coating is preferably applied as a hot melt. Although it is not necessary to apply the coating to all surfaces of the granulate, care must be taken (as in each method of applying the coating layer) to apply an adequate amount of the coating composition so as to obtain the desired weight ratio of the coating to the granulate. Overcoating (that is, the composition of the sprayed coating that does not deposit on the granulate) can be collected, remelted and re-sprayed. The composition of the melted coating can also drip onto the granules instead of spraying it. In the second method, the coating composition can also be applied by transporting the granulate through a melting bath of the coating composition. The granulate can be transported through the molten bath by means of, for example, and without limitation, a conveyor belt or by dipping in batches, such as in a porous metal basket. It is also possible to allow the granulate to cool completely and then to heat the granulate to a desired temperature again before coating it. This reheating can be achieved with, for example, hot air or radiant heat. In this way, the granulate to be the thermoplastic resin body of the custom thermoplastic resins of the invention can be produced and stored for a period of time, then reheated and coated at a later time to form the custom thermoplastic resin. In some cases, it may be beneficial to cool the granulate below the initiation temperature of the melt processing range of the coating composition. For example, during the processes described above in which the molten coating composition is applied to the resin granulate, it may be possible to use cooled granulate to activate the cooling and hardening of the coating to be applied. For example, it may be desirable to use granulate that is at room temperature or below to increase the thickness of the coating layer that can be applied, or to activate the production of the coated granulate. In still another method for coating the granulate, the granulate and the coating composition are charged to a fluidized bed reactor, roller mill, ball mill (with the granulate replacing the steel balls), or disperser equipped with a flat impeller , along with the coating. It is also possible to load the granulate and the individual components of the coating of the hydrophobic resin component, such as a polyolefin wax and the additive or additives such as a pigment or dye. The materials are then processed at a temperature at which the coating or the hydrophobic resin component remains solid. This can be achieved by adding the hydrophobic resin coating or component as a melt, applying heat to the processing vessel after the ingredients are charged, by the heat generated from the friction and shear of the materials during processing or by any combination of these. After processing for a sufficient time to produce a substantially homogeneous coating on the granulate, the coated granulate is cooled, preferably with stirring or by means of a rotary drum to prevent the granulate from agglutinating as the coating solidifies. The coated granulate, or the custom thermoplastic resin of the invention, can be formed into articles according to any of the methods known in the art for thermal fusion processing of the thermoplastic resin compositions. for example, compression molding, vacuum molding, injection molding, thermoforming, blow molding, calendering, casting, extrusion, filament winding, laminating, rotary molding or casting a hollow cast, two-stage molding, Stratification or contacting, stamping and combinations of these methods can be used with custom thermoplastic resins formed by the present methods. Customized thermoplastic resins of the invention can be formed in any of the articles generally made with thermoplastic resins. Among the many possibilities are, without limitation, bases for chairs, connectors and electrical boxes, automotive components that include loudspeaker grilles, mirror boxes and fluid tanks, boxes for mechanical tools, components of electrical items such as refrigerator drawers and handles for oven doors, toys such as plastic building blocks, toothbrushes and films or extruded layers. The invention is further described in the following examples. The examples are merely illustrative and in no way limit the scope of the invention as described and claimed. All parts are parts by weight unless otherwise stated.

EXAMPLE A coating composition is produced as follows: 35 parts by weight of phthalocyanine blue (Heliogen Blue K7090, available from BASF Corp., Mt. Olive, NJ) is combined with 65 parts by weight of Luwax 61 (melting point = 103-111 ° C, available from BASF Corp., Mt. Olive, NJ) in a split hopper kneader, open, for 50 minutes at 150 ° c. The mixture is allowed to cool, is removed from the kneader and then crushed to a coarse powder. A custom thermoplastic resin is prepared as follows: 70 parts by weight of nylon 6 (Ultramid® B3, available from BASF Corp., Mt. Olive, NJ) is composed of 30 parts by weight of chopped glass fibers (3760 chopped strands of PPG Inc., Pittsburgh, PA) in a continuous, double helix extruder, ZSK 40 (Werner &Pfleiderer) at 260 ° C for a throughput of 80 kg / h. Immediately after leaving the nozzle, the strands are run through a 36-inch water bath, after which they are blown with compressed air to remove excess water and then fed through a knife granulator Rotary Scheer. 50 kg of granulate is collected in a 55 gallon metal drum installed to spin the drum. The temperature of the granulate is approximately 120 ° C. 1.5 kg of the coating composition prepared above is added to the drum and the mixture is rotated for a further 10 minutes until the coating composition has uniformly covered the granulate and the temperature of the granulate has cooled to 60 ° C. The coated granulate is dried to a moisture content of 0.08% by weight of the granulate.

The custom thermoplastic resin is then injection molded into ductile bars having uniform blue coloration and appearance and excellent physical properties. The invention has been described in detail with reference to the preferred embodiments thereof. It should be understood, however, that variations and modifications may be made within the spirit and scope of the invention and the following claims. 4

Claims

CLAIMS A custom thermoplastic resin comprising a thermoplastic resin body having a coating thereon; wherein the coating consists of a hydrophobic resin component and at least one additive; and further wherein the hydrophobic resin component has an initiation temperature for its melt processing range below the initiation temperature for the melt processing range of the thermoplastic resin body.
The customized thermoplastic resin according to claim 1, wherein the thermoplastic resin body consists of a polymeric material that is selected from the group consisting of polyesters, polyamides, polyolefins, polystyrenes, polystyrene copolymers, polyacetals, polycarbonates, acrylics, polyether ether ketones, and mixtures thereof.
The customized thermoplastic resin according to claim 1, wherein the thermoplastic resin body consists of a polymeric material that is selected from the group consisting of polyesters, polyamides, polystyrenes, polystyrene copolymers, and mixtures thereof.
The custom thermoplastic resin according to claim 1, wherein the hydrophobic resin component consists of a wax.
The customized thermoplastic resin according to claim 1, wherein the hydrophobic resin component comprises at least one member of the group consisting of hydrocarbon waxes, polyalkylene homopolymers and copolymers of alkenes having from 2 to 10 'carbon atoms , microcrystalline waxes, carnauba waxes, lignite waxes, Fischer-Tropsch waxes, fatty acid esters having from about 12 to about 18 carbon atoms, and mixtures thereof.
The customized thermoplastic resin according to claim 1, wherein the hydrophobic resin component comprises at least one member of the group consisting of polyethylenes, polypropylenes, copolymers of ethylene with alkenes having from 3 to 10 carbon atoms, waxes of carnauba, esters of fatty acids that have from about 12 to about 18 carbon atoms, lignite waxes, and mixtures thereof.
The customized thermoplastic resin according to claim 1, wherein the additive comprises at least one member selected from the group consisting of plasticizers, thixotropes, antioxidants, UV absorbers, optical brighteners, hindered amine light stabilizers, light stabilizers of hindered amides, thermal stabilizers, flame retardants, pigments, dyes, conductive materials, non-fibrous reinforcers, particulate fillers, shock modifiers, elastomers, natural and synthetic rubber particles, lubricants, mold release agents and slip agents , fragrances, antifoaming agents, antioxtants, antistatic agents, antimicrobials, biocides and mixtures thereof.
The custom thermoplastic resin according to claim 1, wherein the coating contains at least one pigment.
The method according to claim 1, wherein the hydrophobic resin component has an initiation temperature for its melt processing range that is greater than about 20 ° C.
The custom thermoplastic resin according to claim 1, wherein the hydrophobic resin component has an initiation temperature for its melt processing range that is greater than about 60 ° C.
11. The custom thermoplastic resin according to claim 1, wherein the hydrophobic resin component has an initiation temperature for its melt processing range that is greater than about 80 ° C.
12. The customized thermoplastic resin according to claim 1, wherein the hydrophobic resin component has an initiation temperature for its melt processing range at least about 20 ° C below the initiation temperature for the range of fusion processing of the thermoplastic resin body.
13. The customized thermoplastic resin, according to claim 1, wherein the hydrophobic resin component has an initiation temperature for its melt processing range at least about 40 ° C below the initiation temperature for the fusion processing range of the body of thermoplastic resin.
14. The customized thermoplastic resin according to claim 1, wherein the thermoplastic resin body has a substantially cylindrical shape.
15. The customized thermoplastic resin according to claim 1, wherein the thermoplastic resin body is non-pigmented and, furthermore, wherein the coating additive contains at least one pigment.
16. The customized thermoplastic resin according to claim 1, wherein the thermoplastic resin body contains at least one additive that is selected from the group consisting of plasticizers, thixotropes, antioxidants, UV absorbers, optical brighteners, light stabilizers of hindered amines, light stabilizers of hindered amides, thermal stabilizers, flame retardants, pigments, dyes, conductive materials, non-fibrous reinforcers, particulate fillers, shock modifiers, elastomers, natural and synthetic rubber particles, lubricants, release agents mold and sliding agents, fragrances, antifoaming agents, antioxtants, antistatic agents, antimicrobials, biocides and mixtures thereof.
17. The customized thermoplastic resin according to claim 1, wherein the thermoplastic resin body contains a fibrous material.
18. The customized thermoplastic resin according to claim 1, wherein the thermoplastic resin body contains at least one material that is selected from the group consisting of glass fibers, carbon fibers, aramid fibers and combinations thereof .
19. The customized thermoplastic resin according to claim 1, wherein the coating comprises at least one color concentrate.
20. The customized thermoplastic resin according to claim 1, wherein the thermoplastic resin body contains a non-pigmented polyamide resin and, furthermore, wherein the coating comprises a waxy polymeric component and at least one pigment.
21. The customized thermoplastic resin according to claim 1, wherein the average thickness of the coating is up to about 300 microns.
22. The customized thermoplastic resin according to claim 1, wherein the coating is up to about 10% by weight of the custom thermoplastic resin.
23. The customized thermoplastic resin according to claim 1, wherein the coating is up to about 5% by weight of the custom thermoplastic resin.
The custom thermoplastic resin according to claim 1, wherein the additive is up to about 80% by weight of the coating.
The customized thermoplastic resin according to claim 1, wherein the coating consists of up to about 80% by weight of at least one pigment.
The custom thermoplastic resin according to claim 1, wherein the additive comprises at least one pigment, the pigment being present in an amount of up to about 8% by weight based on the weight of the custom thermoplastic resin.
The customized thermoplastic resin according to claim 1, wherein the additive comprises at least one pigment, the pigment being present in an amount of up to about 4% by weight based on the weight of the custom thermoplastic resin.
The customized thermoplastic resin according to claim 1, wherein the additive comprises at least one pigment, the pigment being present in an effective amount.
The customized thermoplastic resin according to claim 1, wherein the hydrophobic resin component is crystalline.
30. The custom thermoplastic resin according to claim 1, wherein the thermoplastic resin body is substantially encapsulated by the coating.
31. A method for customizing a thermoplastic resin, which consists in applying, in at least a part of the thermoplastic resin, a coating comprising a hydrophobic resin component and at least one additive, wherein the hydrophobic resin component has a temperature of initiation for its melt processing range below the initiation temperature for the melt processing range of the thermoplastic resin.
32. The method for customizing a thermoplastic resin according to claim 31, wherein the thermoplastic resin consists of a polymeric material that is selected from the group consisting of polyesters, polyamides, polyolefins, polystyrenes and polystyrene copolymers, polyacetals, polycarbonates, acrylics, polyether ether ketones, and mixtures thereof.
33. The method for customizing a thermoplastic resin, according to claim 31, wherein the thermoplastic resin consists of a polymeric material that is selected from the group consisting of polyesters, polyamides, polystyrenes, polystyrene copolymers, and mixtures thereof.
The method for customizing a thermoplastic resin, according to claim 31, wherein the hydrophobic resin component consists of a wax.
The method for customizing a thermoplastic resin, according to claim 31, wherein the hydrophobic resin component contains at least one member of the group consisting of hydrocarbon waxes, polyalkylene homopolymers and copolymers of alkenes having from 2 to 10 atoms of carbon, microcrystalline waxes, carnauba waxes, lignite waxes, Fischer-Tropsch waxes, fatty acids having from about 12 to about 18 carbon atoms and derivatives thereof, and mixtures thereof.
The method for customizing a thermoplastic resin, according to claim 31, wherein the hydrophobic resin component comprises at least one member of the group consisting of polyethylenes, polypropylenes, copolymers of ethylene with alkenes having from 3 to 10 carbon atoms , carnauba waxes, esters of fatty acids that have from about 12 to about 18 carbon atoms, lignite waxes, and mixtures thereof.
37. The method for customizing a thermoplastic resin, according to claim 31, wherein the additive comprises at least one member that is selected from the group consisting of plasticizers, thixotropes, antioxidants, UV absorbers, optical brighteners, light stabilizers, hindered amines, light stabilizers of hindered amides, thermal stabilizers, flame retardants, pigments, colorants, conductive materials, non-fibrous reinforcers, particulate fillers, shock modifiers, elastomers, natural and synthetic rubber particles, lubricants, mold release agents and slip agents, fragrances, antifoaming agents, antioxtants, antistatic agents, antimicrobials, biocides and mixtures thereof.
38. The method for customizing a thermoplastic resin, according to claim 31, wherein the coating comprises at least one pigment.
39. The method for customizing a thermoplastic resin, according to claim 31, wherein the hydrophobic resin component has an initiation temperature for its melt processing range that is greater than about 20 ° C.
The method for customizing a thermoplastic resin, according to claim 31, wherein the hydrophobic resin component has an initiation temperature for its melt processing range that is greater than about 60 ° C.
The method for customizing a thermoplastic resin, according to claim 31, wherein the hydrophobic resin component has an initiation temperature for its melt processing range that is greater than about 80 ° C.
The method for customizing a thermoplastic resin, according to claim 31, wherein the hydrophobic resin component has an initiation temperature for its melt processing range at least about 20 ° C below the initiation temperature for the range of fusion processing of thermoplastic resin.
The method for customizing a thermoplastic resin, according to claim 31, wherein the hydrophobic resin component has an initiation temperature for its melt processing range at least about 40 ° C below the initiation temperature for the range of fusion processing of thermoplastic resin.
44. The method for customizing a thermoplastic resin, according to claim 31, wherein the thermoplastic resin has a substantially cylindrical shape.
45. The method for customizing a thermoplastic resin, according to claim 31, wherein the thermoplastic resin is non-pigmented and, further, wherein the coating additive contains at least one pigment.
46. The method for customizing a thermoplastic resin, according to claim 31, wherein the thermoplastic resin contains at least one additive that is selected from the group consisting of plasticizers, thixotropes, antioxidants, UV absorbers, optical brighteners, stabilizers of light of hindered amines, light stabilizers of hindered amides, thermal stabilizers, flame retardants, pigments, dyes, conductive materials, non-fibrous reinforcers, particulate fillers, shock modifiers, elastomers, natural and synthetic rubber particles, lubricants, agents mold releasers and slip agents, fragrances, antifoaming agents, antioxating agents, antistatic agents, antimicrobials, biocides and mixtures thereof.
The method for customizing a thermoplastic resin, according to claim 31, wherein the thermoplastic resin contains a fibrous material.
The method for customizing a thermoplastic resin, according to claim 31, wherein the thermoplastic resin body contains at least one material that is selected from the group consisting of glass fibers, carbon fibers, aramid fibers and combinations of these.
The method for customizing a thermoplastic resin, according to claim 31, wherein the coating comprises at least one color concentrate.
The method for customizing a thermoplastic resin, according to claim 31, wherein the thermoplastic resin body contains a non-pigmented polyamide resin and, further, wherein the coating comprises a waxy polymer component and at least one pigment.
The method for customizing a thermoplastic resin, according to claim 1, wherein the average thickness of the coating is up to about 300 microns.
52. The method for customizing a thermoplastic resin, according to claim 31, wherein the coating is up to about 10% by weight of the custom thermoplastic resin.
53. The method for customizing a thermoplastic resin, according to claim 31, wherein the coating is up to about 5% by weight of the custom thermoplastic resin.
54. The method for customizing a thermoplastic resin, according to claim 31, wherein the additive is up to about 80% by weight of the coating.
55. The method for customizing a thermoplastic resin, according to claim 31, wherein the coating consists of up to about 80% by weight of at least one pigment.
56. The method for customizing a thermoplastic resin, according to claim 31, wherein the additive comprises at least one pigment, the pigment being present in an effective amount.
57. The method for customizing a thermoplastic resin, according to claim 31, wherein the additive comprises at least one pigment, the pigment being present in an amount of up to about 8% by weight, based on the weight of the pigment. the custom thermoplastic resin. The method for customizing a thermoplastic resin, according to claim 31, wherein the additive comprises at least one pigment, the pigment being present in an amount of up to about 4% by weight, based on the weight of the pigment. the custom thermoplastic resin. 9. The method for customizing a thermoplastic resin, according to claim 31, wherein the hydrophobic resin component is crystalline. The method for customizing a thermoplastic resin, according to claim 31, wherein the thermoplastic resin body is substantially encapsulated by the coating. A method for producing an article from a custom thermoplastic resin, comprising the steps of: (a) providing a thermoplastic resin granulate; (b) applying to at least a part of the thermoplastic resin granulate, a coating containing a hydrophobic resin component and at least one additive, wherein the hydrophobic resin component has an initiation temperature for its melt processing range below the initiation temperature of the melt processing range of the thermoplastic resin granulate, to produce a custom thermoplastic resin; (c) melting the custom thermoplastic resin and mixing the thermoplastic resin of the granulate and the coating to a substantially uniform mixture; (d) forming the mixture in an article. 2. An article produced according to the method mentioned in claim 59.