CA2161330A1 - Dimensionally stable reinforced thermoplastic pvc articles - Google Patents

Abstract

A composite article comprising a combination of a non-structural component (A) joined with a structural component (B) is disclosed.
The non-structural component does not bear a sustained load stress due to the attachment with the structural component (B). The non-structural component (A) comprises plasticized polyvinyl halide resin, and fiber, such as glass fibers. Plasticizer and fiber are present in sufficient amount to obtain a coefficient of linear thermal expansion resulting therefrom to 0.1x10-5 °K-1 to 4x10-5 °K-1. The structural component (B) is generally selected from the group consisting of a rigid molded, stamped or shaped metal article such as a steel, aluminum or thermoset polymer article, a metal door, a metal door casing, a window pane, and a metal window casing, to name a few examples.
The structural component (B) can be coated or non coated for example in a painted automotive body panel, a RIM molded thermoset polymeric article in the shape of a bumper. The composite combination is useful especially for applications where service temperatures vary significantly such as in automotive exterior trim components, and construction components such as door and window frames and spacers requiring permanent affixing to the structural element(s).

Description

~ro 9412s272 216;~ 3 ~ PCT/USg4/04679 DIMENSIONALLY STABLE REINFORCED THERMOPLASTIC
PVC ARTICLES

Field of The Invention This invention relates to composite articles cont~ining flexible fiber reinforced 5 polyvinyl chloride.

Bac k~round of the Art European patent publication 411 429 published 2-6-91 discloses articles made from high molecular weight polyvinyl chloride, plasticizer, and reinforcement material. The reinforcement material is selected from particulate or fibrous materials. The polyvinyl 10 chloride has a molecular weight in terms of inherent viscosity above 1.0 preferably 1.4 to 1.7. This material is designed to sustain low continuous load and exhibit little or no deflection at high telllpelal~;s. Particulate reinforcement is not distinguished from fiber reinforcen ~nt U.S. patent no. 3,892,692 discloses ethylene vinyl chloride copolymers which are15 plasticized and exhibit improved plasticizer p ~ -ce. The copolymers contain a modulus index of less than 3000 psi as colll~ed with rigid polyvinyl chloride having a modulus of 300,000 psi. Any type of reinforcing fillers can be used among those suggested are clay, iron oxide, calcium carbonate, asbestos, glass, rayon, and mineral wool. This patent does not acknowledge that non-fibrous reinforcement behaves differently with respect to llim~n~ional stability when combined in a plasticized, flexible matrix, as co~llpared to fibrous reinfolcel-.ent Plasticized polyvinyl chloride has been exploited as a useful tough, weatherablematerial. US-A-3 084 078 is a general disclosure of phth~l~t~ ester, a widely used plasticizer. US-A-2 535 643 discloses a class of plasticizers and any usual commercial PVC (see column 3, lines 20-22). US-A-3 796 681 is directed to plastisols.
EP-A-0 057 470 broadly shows non-reinforced plasticized PVC.

21~1330 The fiber reinforcing of rigid thermoplastics has been commercially exploited instructural uses to provide for rigidity (modulus enhancement) beyond that obtainable from the rigid thermoplastic matrix alone. Chopped glass fibers having a diameter from about 10 microns to about 25 microns have been commerciall~ developed specifically S for this purpose. The addition of glass fibers to a rigid thermoplastic matrix resin reduces the coefficient of linear thermal expansion (CLTE) of the composite. There are practical upper limits on the amount of glass fiber content usable with PVC, hence limits on the extent of reduction in CLTE using glass fibers alone with PVC.

There has been observed an inverse relationship between CLTE of the fiber reinforced 10 composite and the tensile modulus of the thermoplastic matrix of the composite. That is, when one Co~ J~eS the coefficient of linear thermal expansion of two different glass fiber reinforced thermoplastics, the matrix which has the lower modulus will exhibit a relatively higher CLTE for the reinforced composite.

In some end use applications for non-structural thermoplastic polymers, the high tensile 15 or flexural modulus is not nPedPrl, however due to poor ~iim~n~ional stability, the decigner often is of the belief that high modulus is needed to prevent distortions in the article. The present invention is contrasted with conventional approaches suggesting high structural strength. The composites of the present invention contain a non-structural colllpollent which has low modulus and strength however, this component 20 possesses an improved degree of dimensional stability, thereby avoiding the build-up of load stress under çh~nging environmental conditions of exterior applications. The high ~limen~ional stability of the non-structural colnpollent in this invention, over a broad tclllpcl~ re range, is sufficient to enable close tolerance fit with the structural component without distortion of the non-structural component. When fibers are present 25 in a viscous thermoplastic melt undergoes, during processing there is fiber orientation along shear force lines, this may result in non-uniform CLTE throughout the article, possibly resulting in later distortion. It is desirable to achieve a less random orientation of fiber reinforcement in the thermoplastic matrix in order to obtain the lowest CLTEin one direction, especially for elongated articles having high aspect ratio.

,VO 94/25272 21~ ) PCT/US94/04679 SummarV of the Invention In accordance with the invention there is provided a composite of a reinforced, plasticized polyvinyl halide composition (A) integrally bonded to a structural member (B) by mechanical or adhesive f~ctening means. The structural component (A) is selected from the group concisting of metal sheet, shaped metal articles, rigid thermoplastic, and rigid thermoset articles. The composite optionally and preferably further comprises an apl)edldllce (C) layer overlying (A) on the surface not cont~cting (B). The appedldllce layer (C) can completely surround (A) or cover only the show side with a small portion e~t.?n~ling around the edge of the show side so as to provide a area for ~ .ing (C) which is not seen. Preferably (C) comprises a thermoplastic compound such as non-reinforced, pigm~nt~d plasticized polyvinyl halide composition, decorative paint and the like. The structural component (B)is generally selected from the group consicting of a rigid molded, stamped or shaped metal article such as a steel, all-minl-m or thermoset polymer article, a metal door, a metal door casing, a window pane, and a metal window casing, to name a few examples. The structural component (B) can be coated or non-coated for example in a painted automotive body panel, a RIM molded thermoset polymeric article in the shape of a bumper. Co,llpolle.lt (A) is most advantageously formed in the shape of an auto body side molding, weather seal profile, cove trim piece for pools and auto bulnpel fascia, to name a few examples.
Component (A) is a non structural col.lponellt and does not have the capability to sustain stress loading. Structural component (B) must be joined with (A).

Compol1elll (A) comprises: a PVC miscible plasticizer, polyvinyl chloride homopolymer resin, and fibers. The polyvinyl chloride exhibits a preferred intrinsic viscosity measured according to ASTM D1243 of from 0.4 to 0.9. Molecular weightsin terms of inherent viscosity of between 0.5 and 0.7 exhibit the best combination of melt strength and flowability. The preferred (A) component has poorer sag strength than materials taught in EP 411 429, and is not as useful for structural strength.
Plasticizer is present at a level of from about 15 weight parts to about 150 weight parts per 100 weight parts polyvinyl halide resin in (A). Plasticizer is preferably present in (A) at from 20 weight parts to 55 weight parts per 100 weight parts polyvinyl halide in 2 21613 ~ o PCT/US94/04679 (A). Fibrous reinforcing material can be selected from the group consisting of chopped glass fibers and polymeric fibers, such as~aramid, polyarnide, polymethacrylate, fibrous derivatives of cellulose non-glass fibers are usable but less preferred for economic and technical reasons. In addition to plasticizer component (A) can further contain a 5 flexible polymeric material, for example, EVA, SBR, NBR, MBS, acrylic rubber, ABS, urethane, copolyester, styrenic block rubbers, any of which may or may not be completely miscible with PVC.

Component (A) exhibits among the lowest coefficient of linear thermal expansion per ASTM D696 of any material useful for molding of shaped plastics when sufficient amounts of plasticizer are used. Generally at least 15 weight parts per 100 weight parts PVC is required in (A). The plasticiæd PVC polymer will have a PVC phase having glass transition t~ e of less than 50C. The plasticized PVC matrix has reduced tensile modulus measured per ASTM D638 co",p~ued with rigid fiber reinforced materials. However, because component (A) is joined with a structural component (B), 15 the strength and rigidity are not required in (A). The plasticized, reinforced material exhibits significantly better ~limen~ional stability as shown by CLTE and overcomes the lack of structural strength.

The amount of glass fibers generally can range from 3% to 50% by weight fiber reinforcement material. Dimensionally stability is further improved along with a20 balance of good prope,lies when the glass fibers are present at from 10 to 30 percent by weight. The plefcl,ed chopped glass fibers have a diameter of from about 8 to 25microns and length of from 1 to 25 rnm prior to combining with the thermoplastic.
Upon inco",o,alion into PVC, the glass fibers are broken leaving a variety of fiber lengths. Preferred glass fibers dimensions and 10-13~1m by 3-6 mm. Optional 25 particulate or platelet reinforcement material can also be combined with or can displace a quantity of fiber reinforcement and results in a non-structural material having CLTE
of 4x10-5 K-' or less and a good combination of physical plopcllies. The articles are shaped according to the forming method employed and exhibit a tensile modulus below that of reinforced rigid therrnoplastic PVC, that is a modulus of from about 0.1 Gpa to 30 about 0.5 Gpa. The coefficient of linear thermal expansion for the preferred ,VO 94/25272 21 ~ 13 ~ Q PCT/US94/04679 embodiments, per ASTM D696, is measured from -30C to +30 C and is found to preferredly lie in a range of from about O.lx10-5 K-' to 4xlO-s K-', more preferably from l.Ox10-5 K-' to 2.9x10-5 K-', and still more preferably from l.Ox10-5 K-' to 2.0x10-5 K-'.

S In accordance with the invention there is provided a composite comprising an extruded non-structural component (A) as above which exhibits a coefficient of linear thermal expansion of from O.lxlO-s K-' to 4x10-5 K-'. (A) is prepared by subjecting the (A) compound to an extrusion process whereby a shaped profile is formed which conforms to the cross-section of the extruder die. The prefe.led extruded non-structural articles 10 are elongated and have an aspect ratio of length to width of at least 2, preferably 4, more preferably about 6 to 50 or more. The fiber orientation provides an improved CLTE in the axial direction, and the magnitude of lineal expansion is desirably very low.

In accordance with the invention there is provided a composite article co~ g non-15 structural conlponen~ (A) formed by injection molding process. The article has excellent ~limPn~ional stability. Using the method of injection molding, the compound is formulated for high melt flowability and the molten material co"~ glass fibers adequately flows to fill the entire void in the mold. The non-structural co~ ,ollent (A) exhibits excellent rlim~n~ional stability and can be used in contact with rigid structural 20 articles with tight size tolerance, without causing a distortion in the weaker component (A).

21~1330 BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a log-log plot of tensile modulus (GPa) on the x-axis versus coefficient of linear thermal expansion ( X 10-5 K-' ) (CLTE) for a variety of materials. The triangular data points include metals, and rigid, fiber reinforced thermoplastics, as well S as rigid non-reinforced thermoplastics. The circular data points are measurements made from examples of the method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The triangular data points in Figure 1 illustrate a plot of CLTE versus tensile modulus for a variety of materials. The symbols used lepl~,selll the following:
CLTE (X10-5 K) P-PVC - plasticized particulate reinforced polyvinyl chloride 36 LDPE - low density non-reinforced polyethylene 1 8 HDPE - high density non-reinforced polyethylene 12 PP - non-reinforced polypropylene 11.2 PS - non-reinforced polystyrene 7.2 PC - non-reinforced polycarl,on~e 7.0 u-PVC - particulate reinforced, non-plasticized rigid polyvinyl chloride 6.3 m~gn~cium 2.6 al~ . 1.8 brass 1.8 copper 1.7 stainless steel 1.6 carbon steel 1.2 The table above illustrates that non-reinforced thermoplastic polymers or particulate reinforced thermoplastic exhibit higher coefficient of linear thermal expansion and 30 relatively lower tensile modulus compared to a like polymer cont~ining glass reinforcement. None of the thermoplastic materials represented by triangles, whether fiber reinforced or not, exhibit a CLTE as close to metals aluminum (Al) magnesium (Mg), brass, Copper (Cu), 316 stainless steel (SS) and carbon steel (steel). They vary ~O 94125272 2 1 6 1 3 3 ~ pcTrus94lo4679 by at least a factor of two, and in many instances by a factor of 7 or more. As the graph depicts, comparing PP to GFPP, as expected, glass fibers increase the tensile modulus and reduce CLTE. With respect to PVC and GFPVC, the same effect is noted.

5 The trend in the triangular data points of figure 1 suggests that the tensile modulus of the matrix material and the CLTE of fiber reinforced versions are inversely proportional. The lower CLTE of examples A- K for glass reinforced, plasticized PVC
does not follow the observed trend in that with a higher proportion of plasticizer there is the expected reduction in modulus, however CLTE is decreased. Reduction of 10 CLTE to this extent is hllpol~lt since these levels of CLTE are very near or can be made equal to that of ~ imil~r structural materials. Because the non-structural compo~ (A) has no structural strength and cannot sustain load stress, the material would easily distort, however due to the excellent ~lim~n~ional stability, no distortion is observed. Also there is no distortion over a wide t~lllpel~ re range making these 15 articles highly desired for exterior decorative trim for automobiles. The composite Col~t~ g non-structural colllponent (A) can have a close match of the CLTE of the structural component (B) to which it is ~tt~chç(l As explained previously, non-structural uses are uses where an article does not bear sustained load stress. Sufficient intemal stresses would lead to pçrm~n.ont distortion or creep for the non-structural 20 component (A) if it were not for the excellent iimPn~ional stability. In many applications the non-structural colllpollent(A) can be tightly attached to the structural component (B) and m~int~in adherence over a wide temperature range and under prolonged themmal cycling without we~kening or colllplolllising the att~chment means.

Conventional methods for attaching the non-structural component (A) to structural 25 component (B) can be used. These include the use of adhesives such as acrylicpressure sensitive adhesives, adhesive coated foam tapes, urethane adhesives, epoxy adhesives, and hot melt adhesives all of which are in commercial use. Mechanicalfasteners or rivetting can be used. Themmal bonding or dielectric heating could be used also, these methods being known and available methods beyond the scope of the 30 invention.

WO 94t25272 21613 ~ O PCT/US94/04679 The plasticized matrix material must exhibit a dominant PVC phase morphology.
Those materials which reduce the modulus`m a blend with PVC but which are immiscible with PVC are less preferred in the present invention. A combination of PVC miscible plasticizer and non-miscible polymer is however useful. Miscibilit 5 herein means that the plasticized matrix must exhibit a Tg which is lower that of a rigid matrix PVC. The matrix may also include lubricants processing aids and at least one stabilizer for PVC. Impact modifiers are not generally required but may be used.
The plotted data point for example A in figure 1 reples~ s the measured l)ropc.lies obtained by combining 35 weight parts of plasticizer with polyvinyl chloride (100 wt.
parts) having an inherent viscosity of 0.68. The CLTE of example A was 3.1 x10-5 K-' and is lower than rigid unplasticized PVC shown in figure 1 having a CLTE of 3.2 x105 K-~. The modulus of example A was 1.4 GPa versus S.l GPa for rigid, glass reinforced, unplasticized PVC.

Example B plotted in figure 1 resulted from the combination of 100 wt. parts PVC(I.V. 0.52) with 10 parts of polyacrylate proces~ing aid and 35 parts of mixed alkyl (C,-Cg-C~,) phth~l~te plasticizer, stabilizer, lubricants, and an amount of 0.25 x 13 micron glass fibers siæd with aminosilane coupling agent such that the total composition contained 30% by weight of glass fibers. As figure 1 shows the modulus of example B
has been reduced below that of rigid GFPVC but is higher than example A; and the20 CLTE is also favorably identical to the CLTE of al-.,.,i..--,.~ Al~lminlnn can be used as a substrate for this article over a broad te~ .dlllre range.

Example C represents the combination of 52 weight parts of plasticizer in a compound similar to example B, but having glass fiber content of 20% by weight. There is noted a still further reduction in CLTE versus example B due to the additional plasticizer 25 even though the amount of glass content is 20% by weight in C versus 30% by weight in B. The modulus of C is reduced from 1.9 GPa to 0.79 GPa, yet the m~gnit~l(le of tensile modulus is not of primary concern for the aforementioned uses. Example Dcontains a still lower CLTE than example C yet has a higher tensile modulus as C and for some uses this a more desirable combination of properties.

VO 94125272 ~1613 3 a PCT/US94/04679 g In table 1 below are listed the weight percent glass fiber content and parts plasticizer per 100 weight parts PVC resin for the examples A-K plotted in figure 1.
TABLE I
EXAMPLE CLTE TENSILE % GLASS WT.PARTS
(x10-5 MODULUS CONTENT PLASTICIZER
K ') (GPa) E 2.0 0.18 10% 74 G 1.8 0.11 10% 82 Exd", ~ 'e s E and G have a CLTE below GFPVC. As can be seen from the data above10 that i"c,easi"g the level of p~ lici er from 74 to 82 phr at a fixed weight percent glass content causes a reduction in the coefri~;el,l of linear thermal ex~,ansion.

EXAMPLE CLTE TENSILE % GLASS WT.PARTS
!x10 5 MODULUS CONTENT PLASTICIZER
OK1) ~
C 2.2 0.79 20% 52 D 2.1 1.2 20% 52 H 1.8 0.50 20% 55 J 1.5 0.43 20% 82 K 1.3 0.21 20% 82 As can seen in table 2 that with 20% glass fiber content and a pl~ ; er content of either 52 to 82 parts per 100 parts PVC yields reduced CLTE. It can be also seen that the modulus of the cor"posite is also reduced.

EXAMPLE CLTE TENSILE % GLASS WT.PARTS
(x10'5 MODULUS CONTENT PLASTICIZER
~ ~ (GPa) A 3.1 1.4 30% 35 B 2.4 1.9 30% 35 F 1.9 4.9 30% 35 1.7 0.81 30% 52 As table 3 shows, the plasticizer content of 35 or 52 parts per 100 parts PVC yields a 30% glass fiber reinforced PVC composite having a reduced CLTE.

WO 94/25272 216 13 ~ ~ PCT/US94/04679 , The above examples each contained polyvinyl chloride homopolymer having an I.V.
ranging from 0.5 to 1.1, a stabilizer such as an organotin or a mixed metal soap type, such as a barium-zinc stabilizer. Preferred stabilizers are mixed metal types. The amount of thermal stabilizer used can range from I to 5 weight parts. There can be 5 included other conventional additives such as processing aids, or impact modifiers, pigments or colorants, UV stabilizers and co-stabilizers known in the compounding art.
Impact modifiers are not generally need because of the inherent toughness of theplasticized matrix. The articles exhibit Izod impact strength of at least 1 ft-lb per inch of notch. Preferred processing aids are polyacrylates, for example those commercially 10 available from Rohm and Haas, Inc. under the Paraloid trademark. Most preferred processing aids are styrene-acrylonitrile copolymers. The conventional lubricant waxes, polyol esters, and fatty soaps can be used. The plefe..ed lubricant is a silicate type, in which the resulting surface tension of the surface of a shaped article is higher than 35 dynes/cm, preferably 4~ dynes/cm and most preferably from 45 to 65 dynes/cm2 in 15 order provide improved adhesion to coatings or applied films. In-mold transfer of films during formation is a plefel,~d method of joining one side of the non-structural article to appearance films such as pigmented non-reinforced flexible PVC films. Amounts of from 2 to about 15 weight parts of lubricant can be used, with the type and amount of lubricant and stabilizer depending on factors beyond the scope of this invention.

20 Any of the conventional processes for making PVC polymers such as mass, suspension, solution or emulsion polymerization methods can be used. Mass and suspension polymerization methods are the preferred processes. Suspension polymers are mostpreferred. Porous, commercial suspension grade homopolymer PVC having an l.V. offrom 0.4 to 0.85 are preferred with the more preferred PVC polymers having an I.V. of 25 from 0.5 to 0.7. Generally the molecular weight is controlled by the polymerization temperature and/or by the use of chain transfer agents.

Although the PVC polymer can be a copolymer of vinyl chloride and terminally unsaturated comonomer(s), it is essenti~l that the PVC resin be a rigid polymer in the unplasticized state, the p.erclled type of rigid polymers being a homopolymer of30 polyvinyl chloride. In the present invention, homopolymers m~int~in better physical ~O 94/25272 21613 ~ O PCT/US94/04679 I I

properties in the plasticized state such as higher strength and modulus. Homopolymers or copolymers of PVC having an unplasticized modulus of elasticity of greater than 100,000 pounds per square inch per ASTM-D747 are essential for use in the present invention. Thus, flexible copolymers of PVC having a Tg in the unplasticized state of less than about 60 C and having an unplasticized modulus for less than 100,000 p.s.i.
are not suitable in the present invention. Block copolymers of homopolymer PVC may be suitable, provided there is a major predominant phase of rigid polyvinyl halide polymer which would meet the above modulus criteria. The use of flexible copolymers obviates the ability to add sufficient plasticizer to produce the CLTE lowering effect and therefore are outside the scope of the invention.

The miscible plasticizer forms a single phase, single Tg PVC matrix and is incorporated at a level of from about 5 weight parts to about 150 weight parts per 100 weight parts polyvinyl chloride resin, the amount in any embodiment depending on the modulus and CLTE desired. More preferably, plasticizer is incorporated at 20 weight parts to 65 weight parts per 100 weight parts polyvinyl chloride.
The formulations of the invention must have adequate melt flowability, usually evaluated by the spiral flow test. Spiral flow is a measure of the extent of injection melt flow under a fixed ram force input. The extent of spiral flow provides a prediction of the limitations in size and configuration of injection molding dies suitable for a given resin compound. The test employs a gr~ te(l 60-inch spiral flow moldwith a standard cross section die such as a 1/8 inch by 3/16 inch rectangular cross section die used in conjunction with a Van Dorn injection molding m~rhine. Generally, the mold telnl,e.dlule is set at 55C, the injection melt pressure is a constant psi, with a constant injection time, clamp time, and mold open time, giving a constant total cycle time. A screw of specified diameter and L/D is used. Stock tell~e~ re at the nozzle is standardized also. Spiral flow is proper when the polymer is able to flow into the pattern of the mold used. The extent of spiral flow varied depending on the molecular weight of the plasticizer, the molecular weight of the polyvinyl halide polymer as well as the amount of reinforcement or other material employed. A desirable spiral flow is at least 15 inches, preferably at least 25 inches, more preferably at least 35 inches, and most preferably at least 40 inches. Contrary to conventional wisdom, it has been found WO 94125272 PCTtUS94/04679 that relatively low molecular weight polyvinyl chloride having an I.V. of from 0.4 to 0.85 works better in the present invention than PVC having molecular weight of 0.9 or above. When the molecular weight of polyvinyl chloride is in a range of from O.S to 0.7, there is exhibited the best combination of melt strength and flowability and less 5 plasticizer is required to give the same spiral flow than with the use of high molecular weight PVC (I.V. above 1.0).

The plasticizers used in this invention are PVC miscible plasticizers to the extent that a single phase morphology results in combination with PVC. These include those taught in The Technolo~Y of Plasticizers, Sears and Darby, John Wiley and Sons, New York (1982) ch.4, incorporated herein by reference. A suitable plasticizer may be polymeric, or monomeric such as a high Tg solid or a low Tg material but there must be a degree of miscibility such that a single phase, single Tg results from their combination. The prefel~ed plasticizers are liquids. The amount of plasticizer employed is the minimum amount nPces~ry to reduce the CLTE to 4 x10-5 K-' or less. Generally from at least 5 15 weight parts per 100 weight parts PVC (phr) is sufficient to provide a noticeable reduction in CLTE provided that the fiber content is sufficiently high, such as 10% by weight or higher. A preferred combination colllains from about 20 to 85 phr plasticizer. By selecting the amount of flber and plasticizer content the desired combinations of tensile modulus and CLTE can be obtained.

Examples of suitable polyesters with molecular weight below 10,000, especially those derived from glutaric or sebacic acid, plasticizers include the phth~l~tes trimellitates, epoxides, aliphatic diesters, and phosph~tes, including mixtures. Preferred are the phth~l~tes trimellitates and epoxides. Examples of preferred phth~l~tes include dioctyl phth~l~te, diisooctyl phth~l~te~ diisodecylphth~l~te; and mixed alkyl esters such as heptyl, nonyl and undecyl phth~l~te. Preferred trimellitates are tri-octyl trimellitate and tri-isononyl trimellitate. The preferred epoxides include epoxidized soybean oil, and epoxidized linseed oil. As used in the present invention, a single plasticizer can be employed, as well as blends of more than one miscible plasticizer. An example of a preferred blend is a blend of 85 parts per hundred parts resin of dioctyl phth~l~te and 5 parts per hundred parts resin of epoxidized soybean oil.

The amount of fiber reinforcement used ranges from about 3 weight percent to about 50 weight percent of the non-structural component (A). Preferably from about 6 weight percent to about 35 weight percent and more preferably from 10%. The most preferred amount of fiber reinforcement material present depends on the particular combination of 5 ploy~lies desired as these properties can be accurately tailored to suit the requirements.

Examples of suitable fiber reinforcement materials include the various glass fiber types, such as E-glass, with or without coupling agents incorporated thereon, either as mats, woven or non woven fibers or chopped; stainless steel shavings; polymeric fibers, such as aramid or cellulosic fibers, and combinations of more than one type of fiber. The 10 preferred fiber reinforcing material has a diameter of greater than or equal to 8 microns, preferably 10 to 13 microns, more preferably at least 12 microns and most preferably about 13 microns, and a length of 1/8" (3 mm) or 1/4" (6 mm). Alternatively, a particular or platelet filler, or both can be included. An example is the combination of glass and mineral filler, the mineral filler being either of spherical or platelet shape. A
15 particulate filler such as calcium carbonate and platelet reinforcement fillers such as mica or talc are exemplary types. Plefel..,d combinations of fiber and platelet reinforcing filler are 30% fiber and 10% platelet, and 20% fiber and 20% platelet, each respectively.

The glass used in this invention can be sized or non-sized. A preferred sizing and coupling agent are disclosed in U.S. Patent 4,536,360 to Rahrig, incorporated herein by reference which describes the use of aminosilane coupling incolyold~ed into a sizing Co~ g a film former which is more basic than polyvinyl acetate. Preferred film formers are polyethers, and silylated polyazamides. Higher physical properties are seen when fii~minQsilane and preferred film formers are present on the glass fibers.

To prepare component (A) it is preferred to first mix plasticizer with the polyvinyl chloride resin in the initial compounding step. Fiber reinforcement material is added subsequently. As a result of the mixing, the reinforcement material, whether initially in WO 941252~1 6 13 3 0 PCT/US94/04679 long glass fibers or not, will be crushed and broken, and will be dispersed relatively uniformly throughout the mixture. A specific method of prep~lion of the composite comprises combining PVC, process aid, plasticizer, stabilizer, filler or pigment, if used, and lubricants in a Henschel mixer. The powder mixture can be fluxed under heat and S shear in a Buss reciprocating extruder. Is preferred to equip the extruder with a hopper and feeding screw through which the glass fibers are added. The polymer compoundand glass lllixlul~ is then sheared to uniformly disperse the glass throughout the melt.
The mixture can be formed into pellets and later molded, extruded, and shaped in any conventional process for forming shaped thermoplastic articles.

10 The alternative would be to combine the process by directly making the melt mixture and shaping directly into the final product. No special precautions are needed to employ con~le.cial PVC extrusion or injection molding processes.

The articles will generally be formed at tel,lpc~ res high enough to induce melt flow under pl~S~ule. The telllpela~ ;s and work level employed are high enough to fuse the 15 resin particles and ensure complete plasticization of the matrix. The pressule should be high enough to extrude an article, or inject the molten composition into a mold pattern, co-extrude a composite article, or co-inject the material with another thermoplastic component such as a ~liccimil7~t plastic substrate. Typically such temperatures range from about 175C to about 235C, and preferably from about 180C to about 210C.20 The pressures are generally those encountered in injection molding and extrusion, co-extrusion, co-injection or l~min~ting processes. The composition is also useful in compression molding, although this process is not favored as a commercial process.

Examples L- M

The following Examples were prepared to illustrate that both glass fibers and talc can 25 be combined in the method at up to 40% and 50% by weight, and enable achieving the advantages of low CLTE in addition to good physical prol)ellies. The following components were combined by batch mixing in a henschel mixer, followed by force vO 94125272 2 1 613 ~ ~ PCT/US94/04679 feeding to a reciprocating single screw extruder equipped with a down-stream port for incorporating glass fibers.
Example - Parts by Weight L M
Suspension PVC (I.V. 1.0) 100 Suspension PVC (I.V. 0.68) - 100 Acrylic process aid 10 10 Mixed (C7-C9-C") Phth~l~tec 50 50 Lubricants 4.4 4.4 Ba-Zn Stabilizer 3 3 Pigment 0.1 0.1 Talc* 30% 20%
* amount based of batch weight Amounts glass were introduced through the port such that the following weight 15 p~,lcellls as obtained:
Examples- weight %
L M
Chopped glass 10 20 Injection molded test plaques were prepared and the following physical ~.ol~e.lies were measured:

F.Y~-mrles L M
Tensile Mod. (psi) 128,000 203,000 Tensile Strength (psi) 2,950 3,800 Tensile Elong (%) 22 5 Notched Izod (ft.-lb./in.) 1.7 1.9 CLTE xlO-s K-' (-30 to +30C)* 2.6 1.8 Spiral Flow, (inches.)/cm. 19.3/49 31.5/34.2 * ASTM D696 From the above data for L and M it can be seen that injection molded samples exhibit a desirable combination, stress/strain, impact strength, and CLTE below that obtainable without the use of a PVC miscible plasticizer. The modulus is not indicative of rigidity, however it is understood that the method of use is for non-structural 5 application. The desired propc,Lies are CLTE of less than 2.9XI0-4 K-~, and impact strength of greater than 1 ft.-lb./inch of notch which is improved as compared to a rigid PVC reinforced composite absent a significant amount of conventional impact modifier.

Claims (20)

IN THE CLAIMS:

1. A composite article comprising the combination of a non-structural component (A) and a structural component (B), component (A) comprises 100 weight parts of polyvinyl chloride as the matrix, from 10 to 150 weight parts of a plasticizer miscible with polyvinyl chloride, and from 3% by weight to 50% by weight of uniformly dispersed fibers, wherein (A) alone exhibits a dominant PVC phase having a glass transition temperature of 50°C or less, and a coefficient of linear thermal expansion per ASTM D696 of from about 0.1x10-5 °K-1 to 4x10-5 °K-1, and wherein component (B) is selected from the group consisting of metal sheet, shaped metal article, rigid shaped thermoplastic article, and rigid shaped thermoset article.

2. The composite of claim 1 further comprising the step of incorporating a particulate or platelet reinforcement material.

3. The composite of claim 1 wherein (A) is formed as an extruded article.

4. The composite of claim 1 wherein (A) is formed by injection molding.

5. The composite of claim 3 wherein (A) has an aspect ratio of 2 or more.

6. The composite of claim 1 wherein said plasticizer in (A) is present at from 20 to 100 weight parts per 100 weight parts PVC, (A) alone exhibiting a coefficient of linear thermal expansion per ASTM D696 of from 1.0x10-5 °K-1 to 2.9x10-5 °K-1.

7. The composite of claim 4 wherein said plasticizer in (A) is present at from 40 to 85 weight parts per 100 weight parts PVC, and (A) exhibits a coefficient of linear thermal expansion measured in any cross-sectional direction of from 1.0x10-5 °K-1 to 2.0x10-5 °K-1.

8. The composite of claim 1 wherein said structural component (B) has a coefficient of linear thermal expansion of less than 3x10-5 °K-1.

9. The composite of claim 8 wherein said structural component is selected from the group consisting of magnesium, brass, aluminum, steel and stainless steel articles.

10. The composite of claim 9 wherein (B) and (A) are joined by mechanical fastening means for joining said articles.

11. The composite of claim 10 wherein (B) and (A) are joined by adhesive means.

12. The composite of claim 1 wherein said non-structural component (A) is shapedto form an automotive side molding and said structural article (B) is an automotive steel body panel.

13. The composite of claim 9 wherein said non-structural article (A) is a cove trim piece for a pool and said structural article (B) is a metal pool wall panel.

14. The composite of claim 9 wherein said non-structural article (A) is a weather seal profile and said structural article is selected from the group consisting of a metal door, a metal door casing, a window pane, a metal window casing, and a fiber reinforced thermoset article.

15. The composite of claim 9 wherein said non-structural article is a construction weather strip and said structural article is a rigid reinforced thermoplastic PVC
construction lineal profile.

16. A process of making a composite article comprising non-structural component comprising:
(a) combining (1) polyvinyl chloride, (2) a plasticizer which is miscible with PVC, (3) and optional filler(s), lubricant(s), stabilizer(s), pigment(s), and impact modifiers;
(b) melt mixing to form a homogenous mixture, and thereafter combining with the mixture glass fibers with mixing such that the fibers are evenly dispersed throughout the mixture to form (A) (c) molding or extruding to form a shaped article which exhibits a coefficient of linear thermal expansion of 4x10-5 °K-1 or less, and (d) joining with a structural article (B) selected from the group consisting of metal sheet, shaped metal article, rigid shaped thermoplastic article, and rigid shaped thermoset article, including combinations.

17. The process of Claim 16 wherein said polyvinyl chloride is a homopolymer of polyvinyl chloride with intrinsic viscosity of from about 0.5 to about 0.7 articles.

18. The process of Claim 16, wherein the amount of plasticizer present is from 40 to 90 weight parts per 100 parts of polyvinyl chloride and said coefficient is reduced to less than 2.0x10-5 °K-1.

19. The process of Claim 16, wherein said plasticizer in (A) is a phthalate ester and said reinforcement material is chopped glass fibers having a diameter of from 8 to 15 µm.

20. The process of Claim 16, wherein said polyvinyl chloride has an intrinsic viscosity of from 0.5 to 0.7 and is present at 100 weight parts, said plasticizer is present at from 20 to 85 weight parts, the reinforcement material is present at from about 5 percent to about 40 percent by weight of the said article, and saidcoefficient is reduced to less than 1.5x10-5 °K-1.