EP4698377A1

EP4698377A1 - Molded composite articles and methods for making the same

Info

Publication number: EP4698377A1
Application number: EP24722096.5A
Authority: EP
Inventors: Bhawesh Kumar; Robin Michelle PEFFER; James Edward CAIRNS; Nathan James Silvernail; Mark Alan ROBINSON; Daniel K. Dei; Pierre REGUER; Jerome BUSZMAK; Tammy YONASHIRO BOCUZZI
Original assignee: PPG Industries Ohio Inc
Current assignee: PPG Industries Ohio Inc
Priority date: 2023-04-21
Filing date: 2024-04-09
Publication date: 2026-02-25
Also published as: AU2024257936A1; WO2024220276A1; CN121038958A; KR20260005943A

Abstract

The present disclosure is directed to molded vehicle components or components of a structure that include a composite material and a surfacing agent, and methods of making the same. The composite material includes a polymeric resin and a fibrous reinforcing material. The surfacing agent includes a microporous sheet adhered to the composite material, the microporous sheet comprising a polyolefinic polymeric matrix; finely divided particulate, inorganic filler distributed throughout the matrix; and a network of interconnecting pores communicating throughout the microporous sheet. Also provided are methods of making the molded vehicle components.

Description

MOLDED COMPOSITE ARTICLES AND METHODS FOR MAKING THE SAME

FIELD

[0001] The present disclosure is directed to molded composite articles, in particular, vehicle components, comprising a composite material and a surfacing agent comprising a microporous sheet.

BACKGROUND

[0002] Composite materials can provide desired mechanical properties at lower weights than metals or other materials. Their use has become widespread in numerous industries. Reinforced composite materials offer a particularly strong substrate. Composite materials may be formed in a number of ways, including molding. Because a composite material combines two or more constituent materials, the surface of the composite material may be rough and require additional treatment before the material can be used, painted, and the like. Improved surface smoothness on molded composites is desired.

SUMMARY

[0003] The present disclosure is directed to molded vehicle components or components of a structure that include a composite material and a surfacing agent, and methods of making the same. The composite material comprises a polymeric resin and a fibrous reinforcing material. The fibrous material may comprise fibers distributed throughout the polymeric resin, having a length of 0.5 to 12 mm, or 0.5 to 6 mm, or 0.5 to 3 mm, or 3 to 6 mm or 3 to 12 mm. Additionally or alternatively, the fibers may have a tensile strength of 300 to 7000 MPa, or 300 to 5000 MPa, or 300 to 2000 MPa, or 500 to 7000 MPa, or 500 to 5000 MPa, or 500 to 2000 MPa, or 1000 to 7000 MPa, or 1000 to 5000 MPa, or 1000 to 2000 MPa. The surfacing agent includes a microporous sheet adhered to the composite material, comprising a microporous sheet adhered to the composite material, the microporous sheet comprising a polyolefinic polymeric matrix; finely divided particulate, inorganic filler distributed throughout the matrix; and a network of interconnecting pores communicating throughout the microporous sheet.

[0004] The present disclosure is further directed to methods of making the molded vehicle components, wherein at least a portion of a mold interior is lined with the microporous sheet, the composite material is added to the mold on top of the microporous sheet, the mold is closed, and the composite material is cured.

DETAILED DESCRIPTION

[0005] The present disclosure is directed to a molded article, in particular, a vehicle component or component of a structure, comprising a composite material and a surfacing agent, wherein the surfacing agent comprises a microporous sheet adhered to the composite material.

[0006] According to the present disclosure, any composite material can be used. Particularly suitable are reinforced composite materials, such as composite materials comprising a polymeric resin, often serving as a matrix, and a reinforcing filler. The composite material may comprise a suitable inorganic and/or organic resin or matrix, such as natural and/or synthetic materials such as resinous components, and/or a filler such as reinforcing or strengthening components, density modifiers, and/or other fillers or performance modifiers.

[0007] The composite material according to the present disclosure may comprise any suitable crystalline, semi-crystalline or amorphous, thermoplastic and/or thermoset resins, compounded compositions, and/or curing agents. Examples of suitable resins and/or matrix components, include polyurethane, amine, amide, acrylonitrile-butadiene-styrene (ABS), low-density polyethylene (LDPE), high-density polyethylene (HDPE), polycarbonate (PC), polyamide (e.g., nylon), high impact polystyrene (HIPS), polypropylene (PP), polyetheretherketone (PEEK), sheet molding compounds, bulk molding compounds, thermoplastic or thermoset molding compounds, epoxy resins, phenolic resins, melamine resins, urea resins, polyetherketoneketone (PEKK), polyaryl ether ketone (PAEK), polymer matrix composites (PMCs), metal matrix composites (MMCs), ceramic matrix composites (CMCs), polyethylene (PE), polyoxymethylene (POM), polystyrene (PS), polyesters (e.g., polyethylene terephthalate (PET) and polyethylene naphthalate (PEN)), polyimides, polyacetals, polyphenylene oxides, polyphenylene sulfides, polyethersulfones, cyclic polyolefins (such as homopolymers of norbornene-based monomers (such as addition polymers and ring-opened polymers), copolymers of a norbornene-based monomer and an olefin-based monomer (such as cyclic olefin copolymers, such as addition polymers and ring- opened polymers, such as a copolymer of norbornene and ethylene, and derivatives thereof), vinyl-based polymers (e.g., acrylic resins, such as polymethyl methacrylates (PMMA)), polystyrenes, polyvinyl chlorides, vinylidene polymers (e.g., such as polyvinylidene chlorides), cellulose resins (e.g., triacetyl cellulose (TAC)), maleimide resins, halogenated resins (e.g., fluoropolymers or chlorinated compounds), silicones, inorganic resins, organic/inorganic hybrids, combinations, and/or derivatives thereof, and the like.

[0008] The composite material may comprise a filler. For example, the composite material may comprise the polymeric resin serving as a matrix in a continuous phase, and fillers such as reinforced fibers dispersed in and distributed throughout the resin matrix. As used herein, “filler” or “filler material” refers to a material that may be used to fill or extend the composition. Optionally, a filler may impart or modify a property, such as color, opacity, thermal stability and/or conductivity, electrical conductivity and/or insulation, tensile strength, modulus, impact strength, crush resistance, fire retardancy, and the like. Any suitable filler may be used including inorganic or organic materials. The filler may be surface treated or otherwise modified by any machining or chemical process. The filler may comprise natural, modified natural such as mined and sized, compounded, separated, and/or treated, and/or synthetic materials and may comprise inorganic and/or organic components and combinations thereof. The surface roughness (Ra) of the composite material alone (that is, the composite material as formed and cured without the microporous sheet of the present disclosure) may vary depending on the type of materials combined in the composite and the manner of forming and curing the composite material. The Ra of the composite material alone may be 3.0 microns or greater, such as 3.5, 4.0, 4.5, 5.0, 5.5 microns or greater. Ra as reported herein was determined as described in the Example section.

[0009] The filler may have any size, particle shape, or geometry. For example, the filler may comprise nano, sub-micron, and/or micron particles or compounded materials. The filler may comprise discrete particles or components, or any other suitable constructions such as chopped or continuous strands, webs, woven mats, and the like. The filler may have a regular or irregular shape. The filler may be spherical, ellipsoidal, cubical, platy or plate-like, acicular (elongated or fibrous), rod-shaped, disk-shaped, prism-shaped, flake-shaped, irregular, rock-like, agglomerates thereof, and any combination thereof. For example, the filler may comprise plate-like materials, such as phyllosilicate materials comprising sheets of silicates. Non-limiting examples of phyllosilicate fillers includes micas, chlorites, serpentine, talc, and clays such as kaolin clay and smectite clay. The filler may be amorphous. The filler may be hollow such as glass or plastic microspheres, and/or gas-filled such as inflatable plastics that expand upon exposure to heat. The filler may be treated or otherwise modified with, for example, corona discharge, mechanical, or chemical treatments, such as silane or other coupling agents or otherwise functionalized to modify bonding, dispersion, or reaction with the composite resin matrix.

[0010] Non-limiting examples of a reinforcing filler include fibrous reinforcing materials (such as short glass fibers) and non-fibrous fillers (such as graphite, kaolin, talc, silica, mica, or wollastonite). Other non-limiting examples of reinforcing fillers include chopped fibers, continuous fibers, filaments, tows, bundles, and combinations thereof. Additionally, the reinforcing fibers can be unidirectionally oriented (i.e., aligned in one direction), multi-directional oriented (i.e., aligned in different directions relative to each other such as 45 degrees, 90 degrees, etc.), or randomly oriented, and the reinforcing fibers can form various structures, including but not limited to a sheet, ply, weave, fabric, nonwoven, woven, knitted, stitched, wound, and braided structure, as well as swirl mat, veil, felt mat, and chopped mat structures. Woven structures may comprise a plurality of woven tows, in which each tow is composed of a plurality of filaments, including thousands of filaments.

[0011] Non-limiting examples of a filler include glass, glass fibers, glass fabric fibers, glass veils, carbon fibers, carbon fiber fabric, carbon fiber veils, graphite, aramid, polyamide, high-modulus polyethylene (PE), polyester, poly-p-phenylene -benzoxazole (PBO), boron, quartz, basalt, ceramic, organic synthetic materials (such as KEVLAR), ceramic, metals (including copper), thermoplastic polymer resin(s), thermoplastic polymer fibers, thermoplastic polymer veils, natural cellulosic fibers such as flax, hemp, jute, cotton, and combinations thereof. Glass fibers may include Electrical or E-glass fibers, A-glass fibers, C- glass fibers, E-CR-glass fibers, D-glass fibers, R-glass fibers, S-glass fibers, or combinations thereof. Carbon fibers may include carbon fibers formed from a polyacrylonitrile (PAN) polymer, a polyethylene, pitch-based carbon fibers, and combinations thereof. When making high-strength composite materials, the reinforcing fibers can have a tensile strength of greater than 3500 MPa.

[0012] In certain examples, a fibrous reinforcing material is distributed throughout the polymeric resin, comprising fibers having a length of at least 0.5 mm, or at least 3 mm, and at most 12 mm, or at most 6 mm, or at most 3 mm. For example, the fibers may be shorter, having a length of 0.5 to 12 mm, or 0.5 to 6 mm, or 0.5 to 3 mm, or the fibers may be longer, having a length of 3 to 6 mm or 3 to 12 mm.

[0013] Depending on the composition of the fibers, they typically have a width of at least 5 microns or at least 6 microns, and at most 20 microns, or at most 10 microns, or at most 7 microns. For example, the fibers may have a width of 5 to 20 microns, or 5 to 10 microns, or 5 to 7 microns, or 6 to 20 microns, or 6 to 10 microns, or 6 to 7 microns.

[0014] Additionally or alternatively, the fibers may have a tensile strength of at least 300 MPA, or at least 500 MPA, or at least 1000 MPA, and at most 7000 MPA, or at most 5000 MPA, or at most 2000 MPa. For example, the fibers may have a tensile strength of 300 to 7000 MPa, or 300 to 5000 MPa, or 300 to 2000 MPa, or 500 to 7000 MPa, or 500 to 5000 MPa, or 500 to 2000 MPa, or 1000 to 7000 MPa, or 1000 to 5000 MPa, or 1000 to 2000 MPa. The fibrous reinforcing material may comprise a woven fabric sheet, a non-woven fabric sheet, or a stitched fabric sheet, that may be impregnated with the polymeric resin of the composite material.

[0015] Tensile strength of fibers may be determined, depending on the composition of the fibers, using ASTM D4018-17 or ASTM D2343-17 (for glass and carbon fibers). Often a single value or range of tensile strength for the fibers is reported by the supplier and relied upon.

[0016] The composite material may further comprise colorants, plasticizers, antioxidants, biocides, UV light absorbers and stabilizers or promoters (such as thermal and electric stabilizers or conductivity promoters), fire-retardants, hindered amine light stabilizers, defoamers, fungicides, dispersing aids, flow control agents, surfactants, wetting agents, release agents, or combinations thereof. As used herein, “colorant” refers to any substance that imparts color and/or other opacity and/or other visual effect to the composition.

[0017] The surfacing agent according to the present disclosure is in the form of a microporous sheet. A material is “porous” (including “microporous”) when it contains spaces, holes, or pores through which liquid or gas may pass. As a microporous sheet, the present surfacing agent is distinct from surfacing agents comprised of curable thermoset or thermoplastic films, which are not porous and may release volatile organic compounds (VOCs) when cured. In addition, the microporous sheet may become “interlocked” with the composite material during molding, often due to penetration of the polymeric resin into the pores of the microporous sheet.

[0018] The calculated percent air by volume of the microporous sheet may be 50% or more, such as 55%, 60%, or 65%, or 50-75%, 55-70%, or 60-65%. The microporous sheet may be a single layer material, or may include two or more layers of material, with or without an intervening layer of a different material between them. Non-limiting examples of suitable surfacing agents of microporous sheets include TESLIN products, such as TESLIN SP, TESLIN HD, TESLIN TS, TESLIN SPID, TESLIN Digital, TESLIN IJWP, TESLIN Security-Grade, TESLIN Food-Grade, TESLIN Bio, TESLIN BLUE, and/or TESLIN EMI/RF, all available from PPG.

[0019] The microporous sheet according to the present disclosure typically comprises a polyolefinic polymeric matrix, finely divided, particulate, inorganic filler distributed throughout the matrix, and a network of interconnecting pores communicating throughout the microporous sheet.

[0020] As used herein, “microporous material”, “microporous membrane”, “microporous sheet”, and like terms are used interchangeably and mean a material having a network of interconnecting pores, wherein, on a treatment-free, coating-free, printing ink- free, impregnant-free, and pre-bonding basis, the pores have a volume average diameter ranging from 0.001 to 1.0 micrometer, and constitute at least 5 percent by volume of the microporous material.

[0021] The polyolefinic polymeric matrix can comprise any of a number of polyolefinic materials known in the art. In some instances, a different polymer derived from an ethylenically unsaturated monomer may be used in combination with the polyolefinic polymers. Suitable examples of such polyolefinic polymers can include polymers derived from ethylene, propylene, and/or butene, such as polyethylene, polypropylene, and polybutene. High density and/or ultrahigh molecular weight (UHMW) polyolefins, such as high density polyethylene, are also suitable. The polyolefin matrix also can comprise a copolymer, for example, a copolymer of ethylene and butene or a copolymer of ethylene and propylene.

[0022] If desired, other thermoplastic organic polymers also may be present in the matrix of the microporous material provided that their presence does not materially affect the properties of the microporous material substrate in an adverse manner. The amount of the other thermoplastic polymer which may be present depends upon the nature of such polymer. Non-limiting examples of thermoplastic organic polymers that may be present in the matrix of the microporous material include low density polyethylene, high density polyethylene, poly (tetrafluoroethylene), polypropylene, copolymers of ethylene and propylene, copolymers of ethylene and acrylic acid, and copolymers of ethylene and methacrylic acid. If desired, all or a portion of the carboxyl groups of carboxyl-containing copolymers can be neutralized with sodium, zinc, or the like. [0023] The microporous sheet of the present disclosure may further comprise finely divided, particulate, inorganic filler distributed throughout the matrix.

[0024] The inorganic filler can include any of a number of inorganic fillers known in the art. The filler can be finely divided and substantially water insoluble to permit uniform distribution throughout the polyolefinic polymeric matrix during manufacture of the microporous material. Generally, the inorganic filler comprises silica, alumina, calcium oxide, zinc oxide, magnesium oxide, titanium oxide, zirconium oxide, and mixtures thereof.

[0025] The filler may be in the form of ultimate particles, aggregates of ultimate particles, or a combination of both. At least about 90 percent by weight of the filler used in preparing the microporous material may have gross particle sizes in the range of from 5 to about 40 micrometers, as determined by the use of a laser diffraction particle size instrument, LS230 from Beckman Coulton. Typically, at least 90 percent by weight of the filler has gross particle sizes in the range of from 10 to 30 micrometers, as determined by the use of a laser diffraction particle size instrument, LS230 from Beckman Coulton. The sizes of the filler agglomerates may be reduced during processing of the ingredients used to prepare the microporous material. Accordingly, the distribution of gross particle sizes in the microporous material may be smaller than in the raw filler itself.

[0026] In addition to the fillers, other finely divided particulate materials may also be employed. Non-limiting examples of such optional materials can include carbon black, charcoal, graphite, iron oxide, copper oxide, antimony oxide, molybdenum disulfide, zinc sulfide, barium sulfate, strontium sulfate, calcium carbonate, and magnesium carbonate. Silica alone or in combination with one or more additional filler materials are particularly suitable.

[0027] The filler typically has a high surface area as defined below, allowing the filler to carry much of the processing plasticizer used to form the microporous material. High surface area fillers are materials of small particle size, materials that have a high degree of porosity, or materials that exhibit both characteristics. The surface area of the filler particles can range from 20 to 900 square meters per gram, e.g., from 25 to 850 square meters per gram, as determined by the Brunauer, Emmett, Teller (BET) method according to ASTM C 819-77 using nitrogen as the adsorbate but modified by outgassing the system and the sample for one hour at 130° C. Prior to nitrogen sorption, filler samples are dried by heating to 160° C in flowing nitrogen (PS) for 1 hour. [0028] The inorganic filler may comprise silica, for example, precipitated silica, silica gel, or fumed silica.

[0029] Different precipitated silicas can be employed as the filler used to prepare the microporous material. Precipitated silicas are well-known commercial materials, and processes for producing them are described in detail in many United States patents, including U.S. Pat. Nos. 2,940,830, 2,940,830, and 4,681,750. The average ultimate particle size (irrespective of whether or not the ultimate particles are agglomerated) of precipitated silicas used is generally less than 0.1 micrometer, e.g., less than 0.05 micrometer or less than 0.03 micrometer, as determined by transmission electron microscopy. Non-limiting examples of suitable precipitated silicas include those sold under the Hi-Sil® tradename available from PPG.

[0030] The inorganic filler particles can constitute at least 10 percent by weight, or at least 25 percent by weight, or at least 30 percent by weight, or at least 40 percent by weight, or at least 50 percent by weight or at least 60 percent by weight, and at most 90 percent by weight, or at most 85 percent by weight, or at most 70 percent by weight of the microporous membrane. For example, the microporous sheet may comprise 10 to 90 weight percent, or 25 to 90 weight percent, or 30 to 90 weight percent, or 40 to 90 weight percent, or 50 to 90 weight percent, or 60 to 90 weight percent, or 10 to 85 weight percent, or 25 to 85 weight percent, or 30 to 85 weight percent, or 40 to 85 weight percent, or 50 to 85 weight percent, or 60 to 85 weight percent, or 10 to 70 weight percent, or 25 to 70 weight percent, or 30 to 70 weight percent, or 40 to 70 weight percent, or 50 to 70 weight percent, or 60 to 70 weight percent of the inorganic filler, based on the total weight of the microporous sheet.. The filler typically is present in the microporous sheet in an amount ranging from 50 percent to about 85 percent by weight of the microporous sheet. The weight ratio of filler to polyolefin in the microporous sheet may range from 0.5:1 to 10:1, such as 1.7:1 to 3.5:1. Alternatively, the weight ratio of filler to polyolefin in the microporous sheet may be greater than 4:1. It is contemplated that higher levels of filler may be employed, as such levels of filler would provide higher surface area available for condensation reactions with the treatment compositions.

[0031] The microporous material used in the molded vehicle component of the present disclosure further comprises a network of interconnecting pores communicating throughout the microporous material. [0032] On a treatment-free, coating free, or impregnant-free basis, such pores can comprise at least 5 percent by volume, e.g., from at least 5 to 95 percent by volume, or from at least 15 to 90 percent by volume, or from at least 20 to 85 percent by volume, or from at least 25 to 80 percent by volume, or from 35 to 75 percent by volume of the microporous material. Often, the pores comprise at least 35 percent by volume, or even at least 45 percent by volume of the microporous material.

[0033] As used herein, the porosity (also known as void volume) of the microporous material, expressed as percent by volume, may be determined according to the following equation:

Equation I: Porosity= IOOH -di/kfel wherein d, is the density of the sample and d2 is the density of the solid portion of the sample.

[0034] Porosity may be measured using a Gurley Densometer, model 4340, manufactured by GPI Gurley Precision Instruments of Troy, N.Y. The porosity values reported are a measure of the rate of air flow through a sample or resistance to an air flow through the sample. The unit of measure for this method is a “Gurley second” and represents the time in seconds to pass 100 cc of air through a 1-inch square area using a pressure differential of 4.88 inches of water. Lower values equate to less air flow resistance (more air is allowed to pass freely). For purposes of the present disclosure, the measurements are completed using the procedure listed in the manual for MODEL 4340 Automatic Densometer.

[0035] The volume average diameter of the pores of the microporous material can be determined by mercury porosimetry using an Autopore III porosimeter (Micromeretics, Inc.) in accordance with the accompanying operating manual. The volume average pore radius for a single scan is automatically determined by the porosimeter. In operating the porosimeter, a scan is made in the high-pressure range (from 138 kilopascals absolute to 227 megapascals absolute). If approximately 2 percent or less of the total intruded volume occurs at the low end (from 138 to 250 kilopascals absolute) of the high-pressure range, the volume average pore diameter is taken as twice the volume average pore radius determined by the porosimeter. Otherwise, an additional scan is made in the low-pressure range (from 7 to 165 kilopascals absolute) and the volume average pore diameter is calculated according to the equation:

Equation II: d=2[v_lr /w +V2r2/w2j/[v\/w-_l+V2/w2] wherein d is the volume average pore diameter, vi is the total volume of mercury intruded in the high pressure range, V2 is the total volume of mercury intruded in the low pressure range, ri is the volume average pore radius determined from the high pressure scan, r2 is the volume average pore radius determined from the low pressure scan, wi is the weight of the sample subjected to the high pressure scan, and W2 is the weight of the sample subjected to the low pressure scan.

[0036] When determining the volume average pore diameter using Equation II , the maximum pore radius detected may be taken from the high- or low-pressure range scans. The maximum pore diameter is twice the maximum pore radius. Since some production or treatment steps, e.g., coating processes, printing processes, impregnation processes, and/or bonding processes, can result in the filling of at least some of the pores of the microporous material, and since some of these processes irreversibly compress the microporous material, the parameters in respect of porosity, volume average diameter of the pores, and maximum pore diameter are determined for the microporous material prior to the application of one or more of such production or treatment steps.

[0037] The microporous materials can be prepared by mixing filler, polyolefin polymer (typically in solid form such as powder or pellets), processing plasticizer, and minor amounts of lubricant and antioxidant until a substantially uniform mixture is obtained. The weight ratio of filler to polymer employed in forming the mixture is essentially the same as that of the microporous material substrate to be produced. The mixture, together with additional processing plasticizer, can introduced to the heated barrel of a screw extruder. A die, such as a sheeting die, can be attached to the extruder to form the desired end shape.

[0038] When the material is formed into a sheet or film, a continuous sheet or film formed by a die may be forwarded to a pair of heated calender rolls acting cooperatively to form a continuous sheet of lesser thickness than the continuous sheet exiting from the die.

[0039] Optionally, the sheet exiting the calendar rolls may then be stretched in at least one stretching direction above the elastic limit. Stretching may alternatively take place during or immediately after exiting from the sheeting die or during calendaring, or multiple times during the manufacturing process. Stretching may take place before extraction, after extraction, or both. Additionally, stretching may take place during the application of the first and/or second treatment compositions, described in more detail below.

Stretched microporous material substrate may be produced by stretching the intermediate product in at least one stretching direction above the elastic limit. The stretch ratio may be at least 1.2, such as at least 1.5 or at least 2, such as in the range of 1.2 to 15, 1.5 to 10, or 2 to 6.

[0040] The microporous sheet may have a final thickness of at least 4 mils (101.6 microns), or at least 5 mils (127 microns), or at least 6 mils (152 microns), and at most 25 mils (635 microns), or at most 18 mils (457 microns), or at most 14 mils (356 microns). For example, the microporous sheet may have a thickness ranging from 4 to 25 mils (101.6 to 635 microns), or 5 to 25 mils (127 to 635 microns), or 6 to 25 mils (152 to 635 microns), or 4 to 18 mils (101.6 to 457 microns), or 5 to 18 mils (127 to 457 microns), or 6 to 18 mils (152 to 457 microns), or 4 to 14 mils (101.6 to 356 microns), or 5 to 14 mils (127 to 356 microns), or 6 to 14 mils (152 to 356 microns).

[0041] The microporous sheet may further comprise any organic or inorganic surface treatments, tie coat, additives, functional groups, resins, plasticizers, processing aids, colorants, pigments, additives, coatings, inks, corrosion modifiers, compounds or materials to protect from lightning strike (such as a metal foil, conductive coating, or conductive woven sheet adhered to the microporous sheet), or other performance enhancing modifiers; these can be incorporated during any stage of manufacture of the microporous sheet or applied to the microporous sheet by any application means known in the art. The microporous sheet surfacing agent may comprise formulary components or manufacturing processes to impart one or more properties such as thermal stability coatings to enhance conveyance and release properties, higher or lower densities, components to increase or decrease stiffness, fracture, gouging and/or tear resistance, biodegradability, electromagnetic interference/radio frequency shielding, and the like. Additionally, the surfacing agents may be treated as described in United States Patent Number 10,888,824 B2, the entirety of which is incorporated herein by reference. As used herein, “colorants” refers to any substance that imparts color and/or other opacity and/or other visual effect to the composition.

[0042] According to the present disclosure, the microporous sheet may be adaptable to the needs of the user. For example, the microporous sheet might be adapted to increase adhesion to the composite and/or any subsequent layer, such as a coating layer, applied to the sheet. The microporous sheet might be adapted to have a selectively strippable surface, such that a subsequent coating layer can be easily removed/peeled off if needed; for example, during surface repair. The sheet can be formulated to have functional groups; for example, silica particles used as the inorganic filler may be surface functionalized before or after incorporation into the polyolefinic polymeric matrix. The sheet can be formulated to include reinforcing material and/or material that imparts lightning strike protection to the molded article, such as the metal foil described in United States Patent Application Publication Numbers 2010/103582 and 2018/257790, both of which are incorporated by reference in relevant part herein. The sheet may be adapted to increase UV resistance of the molded article, such as by incorporation of a UV absorber into the microporous sheet.

[0043] Molded articles such as vehicle components can be made using molding methods known in the art, such as high pressure transfer molding, casting, blow molding, compression molding, such as compression resin transfer molding or melt molding, extrusion molding, transfer molding, extrusion molding, injection molding, for example gas assisted injection molding and injection over-molding, structural foam molding, laminating and/or reaction injection molding, matrix molding, rotational molding, spin casting, transfer molding, thermoforming, such as twin sheet thermoforming and vacuum forming, hydroforming, FRP (fiberglass reinforced plastic) molding, such as hand lay-up molding, resin transfer molding, vacuum bag molding, bladder molding, spray up molding, reaction injection molding, pultrusion, and the like, as well as combinations and variations thereof.

[0044] Molded articles can be made using molding methods comprising additional components known in the art such as but not limited to external or internal mold release agents.

[0045] In accordance with the present disclosure, a method of making a molded vehicle component is provided, comprising 1) lining at least a portion of a mold interior with the microporous sheet; 2) adding the composite material to the mold on top of the microporous sheet, 3) closing the mold; and 4) curing or otherwise hardening the composite material.

[0046] The microporous sheet is typically placed in the mold prior to addition of the composite material, such that at least a portion of a mold interior is lined with the microporous sheet. During the molding process, the sheet will adhere to the composite material. Thus, adherence of the sheet to the composite material occurs during the molding process. Significantly, adherence can be achieved without any additional steps, such as steps of applying a chemical treatment or performing a physical treatment to either the sheet or the composite material, and/or process steps that would increase the adhesion. The deformability of the sheet allows for it to be stretched, lengthened and the like as needed to conform to the composite. If desired, one or more additional components may be placed between the microporous sheet and the composite material, such as the lightning strike foil discussed above. It is also within the present disclosure to apply two microporous sheets with the foil, or any other desired material, between in a “sandwich” formation.

[0047] While the microporous sheet conforms to the composite, it does not conform to the roughness of the composite surface; this may be achieved by filling the defects, dry fibers, pin holes, etc. of the composite material though it is not necessary, and the inventors do not wish to be bound by mechanism. As such, the molded vehicle components according to the present disclosure have a surface that is less rough than that of a comparable composite material without the microporous sheet, which serves as a surfacing agent. As demonstrated in the Examples below, Ra can be reduced by half or more using a surfacing agent according to the present disclosure. For example, a molded composite comprising a microporous sheet has a surface roughness that is at least 10% less than a comparable molded composite material without a microporous sheet, such as at least 20% less, or at least 30% less, or at least 40% less, or at least 50% less, or at least 60% less, or at least 70% less. The Ra can be reduced even further upon application of one or more coating layers. For example, a coated molded composite comprising a microporous sheet has a surface roughness that is at least 40% less than a comparable coated molded composite material without a microporous sheet, such as at least 50% less, or at least 60% less, or at least 70% less, or at least 80% less, or at least 90% less, or at least 95% less.

[0048] The molded article of the present disclosure may be coated after forming without post-cure sanding, in large part due to the smoothness of the surfacing agent. One or more coating layers may be applied to the surface of the molded article. For example, an adhesion layer can be applied, followed by one or more coating layers, such as a basecoat layer and clear coat layer, a monocoat layer, two basecoat layers, and the like. The coating layer can include a tie layer, a printed design such as a logo or decorative design, or a selectively strippable layer, such as a label or those disclosed in US2006/004139 and US2006/106157, and US2006/106161, respectively, all of which are incorporated by reference herein in relevant part. The coating layer may be in any form such as a liquid, paste, powder or sheet, and may be applied by any means, as known to those skilled in the art, upon removal of the molded article of the present disclosure from the mold cavity. Optionally, the coating layer may be applied as part of one or more molding steps, such as but not limited to, injection of a coating into the mold between the microporous sheet layer and the mold cavity.

[0049] The microporous sheet may be coated prior to insertion into the mold, such as with a solvent-based coating. Prior to insertion into the mold, the coating may be applied to the microporous sheet by any means as known to those skilled in the art. Optionally, the microporous sheet may be contacted with a surface layer, such as a coating layer, such as a film, such as a liquid coating layer or a laminate, such as an organic or inorganic polymer or coating sheet, with, or without a backing support material, prior to, or during the process of insertion into the mold. The microporous sheet may be uncoated prior to insertion into the mold.

[0050] The molded articles of the present disclosure may result in parts that are lighter in weight than conventional molded vehicle components. The molded articles of the present disclosure may also be achieved with a more streamlined procedure as compared with traditional molded articles. For example, the sanding step may be eliminated or reduced. Use of the microporous sheets may provide additional stress and strain resistance to the molded article, depending on the thickness of the sheet and the strength of the composite material; for example, a relatively thick sheet (e.g., greater than 10 mils) may impart greater structural stability. The microporous sheet may provide barrier properties including corrosion resistance to the molded article, such as protection against galvanic corrosion in areas where metal fasteners are used to attach the article to other components.

[0051] The molded articles of the present disclosure can be used in any article of manufacture, such as a vehicle or a structure. “Structure” as used herein refers to any part of a building, bridge, transportation infrastructure, oil rig, oil platform, water tower, power line tower, support structures, wind turbine blades, walls, piers, docks, levees, dams, shipping containers, trailers, and any metal structure that is exposed to a corrosive environment. “Vehicle” as used herein refers to in its broadest sense all types of vehicles, such as, but not limited to, automobiles, trucks, buses, tractors, harvesters, heavy duty equipment, vans, golf carts, motorcycles, bicycles, railcars, subway cars, airplanes, helicopters, boats of all sizes and the like.

[0052] Any numerical range recited herein is intended to include all sub-ranges subsumed therein. Singular encompasses plural and vice versa. For example, although reference is made herein to "a" molded article, “a” composite material, “a” microporous sheet, and the like, one or more of each of these and any other components can be used. As used herein, the term "polymer" refers to prepolymers, oligomers and both homopolymers and copolymers, and the prefix "poly" refers to two or more. “Polymer” and “resin” may be used interchangeably herein. “Including”, “such as”, “for example” and like terms mean “including/such as/for example but not limited to”. Although the present disclosure is described in terms of “comprising”, the terms “consisting essentially of’ and “consisting of’ are also within the scope of the disclosure.

[0053] The following examples are intended to illustrate the disclosure and should not be construed as limiting in any way. It is understood that the disclosure of this specification is not necessarily limited to the examples described in this section. Components that are mentioned elsewhere in the specification as suitable alternative materials for use, but which are not demonstrated in the working Examples below, are expected to provide results comparable to their demonstrated counterparts.

EXAMPLES

[0054] Flat, compression molded, fiber-reinforced polyurethane composite panels were prepared with or without the use of a standard external mold release agent and/or with or without microporous membrane sheets as a surfacing agent. At least a portion of the mold interior was lined with the microporous sheet, a curable composite material was added to the mold on top of the microporous sheet, the mold was closed, and the composite material was cured, forming a polyurethane composite.

[0055] The molded composite panels were coated using a standard process of sealer/colored basecoat/clear coat as described in Table 1 or with a process including an adhesion promoter as described in Table 2. All products recited in Tables 1 and 2 are available from PPG Industries, Inc. and were applied in accordance with manufacturer’s instructions.

Table 1 Standard Coating Process C

Table 2 Adhesion Promoter Coating Process A [0056] Coated panels were tested for crosshatch adhesion after 1 day and 7 days using ASTM D3359-23 standard test method B for rating adhesion by tape test, as follows: Eleven parallel cuts, 2 mm spaced apart, were made using a cutting device. The length of the cuts was about 35 mm. Cuts were made through the coating and the surfacing agent into the fiber- reinforced polyurethane composite. After making eleven parallel cuts, the surface was gently cleaned with a soft brush or towel. An additional eleven cuts were made at 90° in relation to and centered on the original cuts. A tape was placed over the grid of cuts and removed rapidly after 5 seconds. Eleven parallel lines in both 0° and 90° made a grid with 100 squares. After removing the tape, the number of debonded squares (if any) in the grid were counted and the edges of the squares were checked for smoothness. The classification of adhesion test results was based on the debonded area. For example, if edges of the cuts were smooth and there were no debonded squares, then the classification was 5B (best performance). If less than 5% of the area was affected, then the classification was 4B.

[0057] Table 3 shows crosshatch adhesion results of coated molded composite panels with coating process C or coating process A with an adhesion promoter prior to coating. All coated panels comprising Teslin surfaced mold composites showed adhesion classification of 5B.

TABLE 3 CRQSSHATCH ADHESION OF COATED COMPOSITE PANELS

'Teslin SP 700 (178-micron) microporous sheet comprising a polyolefinic polymeric matrix; finely divided particulate, inorganic filler distributed throughout the matrix; and a network of interconnecting pores communicating throughout the microporous sheet, commercially available from PPG ²Teslin SP 1400 (356-micron) microporous sheet comprising a polyolefinic polymeric matrix; finely divided particulate, inorganic filler distributed throughout the matrix; and a network of interconnecting pores communicating throughout the microporous sheet, commercially available from PPG

[0058] Surface roughness was measured on molded composite panels using a Mitutoyo profilometer (Surftest SJ-210). A line scan was used at three locations on the panel (Top, Middle, and Bottom) and the average of the three measurements was report as Ra. Surface roughness was measured on molded composite panels with and without the coating system described in Table 1. Surface roughness is shown in Table 4.

Table 4

[0059] As shown in Table 4, the molded composite articles of the present disclosure (Examples 1, 1C, 3, and 3C) demonstrated improved smoothness compared to the corresponding articles that did not include the surfacing agent. That is, the average surface roughness (Ra) of uncoated molded composite panels with surfacing agents Teslin SP 700 and Teslin 1400 (Examples 1 and 3) was less than the average surface roughness of an uncoated molded composite panel without Teslin (Example X), and Examples that included a coating provided similar results; Examples 1C and 3C had lower average surface roughness than Example XC.

[0060] Whereas specific aspects of the disclosure have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the disclosure which is to be given the full breadth of the claims appended and any and all equivalents thereof.

Claims

What is claimed is:

1. A molded vehicle component comprising:

1) a composite material comprising: a) a polymeric resin; and b) a fibrous reinforcing material comprising fibers having a length of 0.5 to 12 mm, or 0.5 to 6 mm, or 0.5 to 3 mm, or 3 to 6 mm or 3 to 12 mm, distributed throughout the polymeric resin; and

2) a surfacing agent comprising a microporous sheet adhered to the composite material, the microporous sheet comprising a polyolefinic polymeric matrix; finely divided particulate, inorganic filler distributed throughout the matrix; and a network of interconnecting pores communicating throughout the microporous sheet.

2. The molded vehicle component of Claim 1, wherein the composite material comprises sheet molding compounds, bulk molding compounds, thermoplastic or thermoset molding compounds, polymer matrix composites, metal matrix composites, ceramic matrix composites, or combinations thereof.

3. The molded vehicle component of Claim 1 or 2, wherein the polymeric resin comprises a polyurethane, polyamine, acrylonitrile-butadiene-styrene, low-density polyethylene, high-density polyethylene, polycarbonate, polyamide, high impact polystyrene, polypropylene, polyetherketone, an epoxy resin, a phenolic resin, a melamine resin, a urea resin, polyaryl ether ketone, polyoxymethylene, polystyrene, polyester, polyimide, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyethersulfone, cyclic polyolefin, a copolymer of a norbornene-based monomer and an olefin-based monomer, vinyl-based polymer, cellulose resin, a maleimide resin, a halogenated resin, silicone, an inorganic resin, an organic/inorganic hybrid resin, or combinations thereof.

4. The molded vehicle component of any preceding claim, wherein the fibers have a width of 5 to 20 microns, or 5 to 10 microns, or 5 to 7 microns, or 6 to 20 microns, or 6 to 10 microns, or 6 to 7 microns.

5. The molded vehicle component of any preceding claim, wherein the microporous sheet comprises 10 to 90 weight percent, or 25 to 90 weight percent, or 30 to 90 weight percent, or 40 to 90 weight percent, or 50 to 90 weight percent, or 60 to 90 weight percent, or 10 to 85 weight percent, or 25 to 85 weight percent, or 30 to 85 weight percent, or 40 to 85 weight percent, or 50 to 85 weight percent, or 60 to 85 weight percent, or 10 to 70 weight percent, or 25 to 70 weight percent, or 30 to 70 weight percent, or 40 to 70 weight percent, or 50 to 70 weight percent, or 60 to 70 weight percent of the inorganic filler, based on the total weight of the microporous sheet.

6. The molded vehicle component of any preceding claim, wherein the microporous sheet has a thickness of 4 to 25 mils (101.6 to 635 microns), or 5 to 25 mils (127 to 635 microns), or 6 to 25 mils (152 to 635 microns), or 4 to 18 mils (101.6 to 457 microns), or 5 to 18 mils (127 to 457 microns), or 6 to 18 mils (152 to 457 microns), or 4 to 14 mils (101.6 to 356 microns), or 5 to 14 mils (127 to 356 microns), or 6 to 14 mils (152 to 356 microns).

7. The molded vehicle component of any preceding claim, wherein the microporous sheet (i) has a selectively strippable surface, (ii) comprises functional groups, (iii) includes reinforcing material and/or material that imparts lightning strike protection to the molded vehicle component, and/or (iv) increases UV resistance of the molded vehicle component.

8. The molded vehicle component of any preceding claim, further comprising (i) one or more coating layers comprising an adhesion layer, a basecoat layer, a clear coat layer, a monocoat layer, a tie layer, a printed design, and/or a selectively strippable layer; (ii) one or more lightning strike foils; and/or (iii) one or more additional microporous sheets.

9. The molded vehicle component of any preceding claim, wherein average surface roughness of the molded vehicle component is at least 10% lower, or at least 20% lower, than that of a molded vehicle component comprising a composite material without the surfacing agent adhered thereto.

10. A molded vehicle component comprising:

1) a composite material comprising: a) a polymeric resin; and b) a fibrous reinforcing material comprising fibers, the fibers having a tensile strength of 300 to 7000 MPa, or 300 to 5000 MPa, or 300 to 2000 MPa, or 500 to 7000 MPa, or 500 to 5000 MPa, or 500 to 2000 MPa, or 1000 to 7000 MPa, or 1000 to 5000 MPa, or 1000 to 2000 MPa; and

11. The molded vehicle component of Claim 10, wherein the composite material comprises sheet molding compounds, bulk molding compounds, thermoplastic or thermoset molding compounds, polymer matrix composites, metal matrix composites, ceramic matrix composites, or combinations thereof.

12. The molded vehicle component of Claim 10 or 11, wherein the polymeric resin comprises a polyurethane, polyamine, acrylonitrile-butadiene-styrene, low-density polyethylene, high-density polyethylene, polycarbonate, polyamide, high impact polystyrene, polypropylene, polyetherketone, an epoxy resin, a phenolic resin, a melamine resin, a urea resin, polyaryl ether ketone, polyoxymethylene, polystyrene, polyester, polyimide, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyethersulfone, cyclic polyolefin, a copolymer of a norbornene-based monomer and an olefin-based monomer, vinyl-based polymer, cellulose resin, a maleimide resin, a halogenated resin, silicone, an inorganic resin, an organic/inorganic hybrid resin, or combinations thereof.

13. The molded vehicle component of any of claims 1 to 12, wherein the fibrous reinforcing material comprises a woven fabric sheet, a non-woven fabric sheet, or a stitched fabric sheet.

14. The molded vehicle component of claim 13, wherein the fibrous reinforcing material is impregnated with the polymeric resin.

15. The molded vehicle component of any of claims 10 to 14, wherein the microporous sheet comprises 10 to 90 weight percent, or 25 to 90 weight percent, or 30 to 90 weight percent, or 40 to 90 weight percent, or 50 to 90 weight percent, or 60 to 90 weight percent, or 10 to 85 weight percent, or 25 to 85 weight percent, or 30 to 85 weight percent, or 40 to 85 weight percent, or 50 to 85 weight percent, or 60 to 85 weight percent, or 10 to 70 weight percent, or 25 to 70 weight percent, or 30 to 70 weight percent, or 40 to 70 weight percent, or 50 to 70 weight percent, or 60 to 70 weight percent of the inorganic filler, based on the total weight of the microporous sheet.

16. The molded vehicle component of any of claims 10 to 15, wherein the microporous sheet has a thickness of 4 to 25 mils (101.6 to 635 microns), or 5 to 25 mils (127 to 635 microns), or 6 to 25 mils (152 to 635 microns), or 4 to 18 mils (101.6 to 457 microns), or 5 to 18 mils (127 to 457 microns), or 6 to 18 mils (152 to 457 microns), or 4 to 14 mils (101.6 to 356 microns), or 5 to 14 mils (127 to 356 microns), or 6 to 14 mils (152 to 356 microns).

17. The molded vehicle component of any of claims 10 to 16, wherein the microporous sheet (i) has a selectively strippable surface, (ii) comprises functional groups, (iii) includes reinforcing material and/or material that imparts lightning strike protection to the molded vehicle component, and/or (iv) increases UV resistance of the molded vehicle component.

18. The molded vehicle component of any of claims 10 to 17, further comprising (i) one or more coating layers comprising an adhesion layer, a basecoat layer, a clear coat layer, a monocoat layer, a tie layer, a printed design, and/or a selectively strippable layer; (ii) one or more lightning strike foils; and/or (iii) one or more additional microporous sheets.

19. The molded vehicle component of any of claims 10 to 18, wherein average surface roughness of the molded vehicle component is at least 10% lower, or at least 20% lower than that of a molded vehicle component comprising a composite material without the surfacing agent adhered thereto.

20. The molded vehicle component of any of claims 1 to 19, wherein the vehicle is an automobile or airplane.

21. A method of making the molded vehicle component of any preceding claim, wherein at least a portion of a mold interior is lined with the microporous sheet, the composite material is added to the mold on top of the microporous sheet, the mold is closed, and the composite material is cured.

22. The method of Claim 21, wherein the method excludes any additional chemical or physical treatment steps to the microporous sheet or the composite material.

23. Use of the molded vehicle component of any of claims 1 to 19 in an automobile or airplane.

24. A molded component of a structure, comprising:

2) a surfacing agent comprising a microporous sheet adhered to the composite material, the microporous sheet comprising a polyolefinic polymeric matrix; finely divided particulate, inorganic filler distributed throughout the matrix; and a network of interconnecting pores communicating throughout the microporous sheet; wherein the structure comprises a building, bridge, transportation infrastructure, oil rig, oil platform, water tower, power line tower, support structure, wind turbine blade, wall, pier, dock, levee, dam, or shipping container.

25. A molded component of a structure, comprising: