CA1145915A - Compounding mica and resin with heat sensitive additives - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Mica and melt forming resins are rapidly compounded in a continuous process. The mica has a coating which is pro-vided by contacting the mica particles with a heat sensitive additive comprising chlorinated hydrocarbon. The melt forming resin is one formed from monomers comprising olefinic hydro-carbon monomers. The continuous method involves contacting molten resin with the coated mica and kneading the molten resin and coated mica to mix the same.

Description

s COMPOUNDING_MICA AND RESIN WITH HEAT SENSITIVE
ADDITIVES
- This inven-tion relates to compounding mica and certain melt forming.resin with heat sensitive:additives, such:as chlorinated waxes, that.act as coupling agents therefor and includes, in particuIar, a compounding oper-ation that permits advantageous temperature control and rapid development of desirable physical properties.
Our copending Canadian patent application Serial No- 297,224 f.iled February 17, 1978 discloses that certain chlorinated aliphatic compounds can act as coupling agents for mica and certain melt forming resins.
French.Patent No. 2,124,315 discloses a variety of techniques for compounding mica into.:an organic poly-meric matrix and suggests dispersing the mica particlesin thermoplastic resin prior to attainment of processing conditions.
A process has now been discovered that provides : for compounding of mica and melt forming resin with heat : 20 sensitive additives such:as chlorina-ted waxes at times less than a minute, if desired, whereby molding precursors are prepared that may be used in conventional malding operations to yield molded objects o~ highly desirable physical properties.
The precise conditions under which such ca~unding is accomplished are quite critical. Chlorinated aliphatic compounds such as heat sensitive chlorinated waxes herein are subject to reduction or even elimination of beneficial effects upon undesired decomposition with heat. Such decomposition is particuIarly acute during compounding with melt forming resin and mica particles since the mica particles act as heat sinks that are insulated.by ~: the:resin durlng compounding and may, under conditions of hiyh shear and mechanical heat generated thereby during intense mixing, cause compounding temperatures in excess of that which causes undes.ired decomposition, even though : cooling is attempted.
On the other hand, low temperatures during such compounding, even if at.tainahle, can lengthen the time .

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required for coupling agents such as chlorinated waxes or other chlorinated aliphatic compounds to exhibit desired effect and consequently cause perhaps less efficient use of equipment or modification of existing equipmen-t so as to extend periods at elevated temperature.
Even still further, however, very high shear can even cause deterioration of melt forming resin to an extent that the filled resins are undesirably brittle even though other properties may be satisfactory. Thus 7 for example, the high:shear used to provide a molten resin in the process of this invention has to be controlled so as to keep the melt index (ASTM D1238) of the compounded resin preferably below about 15.
This invention relates to compounding mica and 15 certain melt forming resins with heat sensitive additives, ~ :
such:as chlorinated waxes or other chlorinated aliphatic compounds that act as coupling agents therefor by, in general terms~ making the resin molten (desirably with high shear), introducing mica particles previously blended with the~ particuIate additives into the molten resin and kneading with reduced shear and mica particles and resin into a homogeneous melt.
In accordance with the present invention, there is provided a continuous method for rapidly compounding mica, additi~e and melt-forming resin made from monomers comprising olefinic hydrocarbon monomers wherein the mica is intimately admixed with heat-sensitive additive comprising chlorinated hydrocarbon wax to form a particulate blend, which method comprises: (A~ subjecting the resin to high shear to provide a molten mas:s comprising the resin, (B) contacting the molten resin with the blend comprising intimately admixed mica and chlorinated hydro-carbon wax at a temperature below that at which chlorine containing gas would evolve from the additivei (C) kneading 35 the molten resin and the blend at low shear to provide a mixing thereof, In one preferred embodiment.7 the melt forming resin, e,g. polypropylene, is formed into at least two counter~rotating, parallel molten streams that contact i .,",,,;
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5~3~5 2a one another to ~orm a turbulence therebetween~ and the blend of particles are introduced into such turbulence allowing their rapid and effective dispersement thrcughout the molten :: :

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resin with low shear kneading.
Compounding in this manner permits temperature control not otherwise easily~at.talnable when mica particles and melt forming resin are admixed under conditions of high shearO Such high shear can impart to the melt of resin and mica particles sufficient mechanical work as to generate temperature increase that is not easily con-trollable. Kneading or low shear mixing, however, permits effective mixing of the mica and molten resin in short periods when done in accordance with this invention so that the mica particles are not at high.temperature for extended periods under shear forces that cause such uncon-,trollable temperature increase and consequent undesired degadation of heat sensltive additives. Moreover, compounding in accordance with 'this invention does not expose the mica to shear forces that undes.irably break such.mica thereby exposing mica surfaces without heat sensitive 'coupling agents. Surprisingly, mica that is blended with particulate, heat sensitive additives may be compounded with,melt forming resins such as polypropylene such that the total processing time at high temperature is as little as 15 seconds or less and yet provide malding precursoxs, e.g. pellets, which.yield molded articles with:desirable properties.

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~ uring compounding in accordance with this invention, it is particularly desirable that the melt forming resin receive high shear (prior to mica incorporation~ that is sufficient to provide rapidly a molten mass of resin at desired temperatures but insufficient to cause significant change of the resin's properties. For example, it is preferred that a melt forming resin such as polypropylene having a melt index tAsTM D1238) below about 6 not undergo such shear prior to mica incorpOratiQn as to raise its melt 10 index (ASTM D1238) above 15, even more preferably such that it is not above 12. Otherwise, final composites will have an undesired brittleness.
On the other hand, it is preferred to provide molten resin at a temperature (prior to incorporation of the mica and 15 additive into the resin) at least about 10F below that temperature at which the additive first releases chlorine cont~ining gas. To achieve maximum benefit of the additive in as short as time as possible, however, incorporation of mica ~ and additive into the resin should be such that the resin has 20 an initial temperature not more than about 60F (preferably, not more than abou~ 50F) below that temperature at which the additive releases chlorine containing gas.
.A ' The melt forming resins that may be advantayeously compounded with mica and heat sensitive additives in accordance with this invention include commercially available materials that are designed for use in molding ~such as by injection, compression, stamping etc.) processes. Of these 30 commercial resins thermoplastics made from monomers comprising olefinic hydrocarbons such as ethylene, propylene, styrene, etcO are of special interest in that they can yield molded, mica containing articles with high strength and desirable resistance to heat distortion as well as economic advantage.

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s~s - s -Melt forming resins made from monomers comprising olefinic aliphatic hydrocarbon monomers such as ethylene, - propylene and the like can be compounded especially well and particularly desirable results are achieved with melt forming .~3 5 resins sold as polypropylene resins e.g. Gulf Polypropylene 6420 MHP, Hercules Profax 6S23 Polypropylene. Normally such resins desirably have intrinsic viscosities above about 1.5 and preferably between about 2.0-2.6 for more expedient processing, although suitable modification will allow 10 processing of resins with oth~r viscosities. An important criterion, however, in selection of desirable melt forming resin is that it remain sufficiently molten at processing temperatures that do not degrade the efficiency of the heat sensitive additives. Moreover, the melt forming resin 15 preferably has a meit index (ASTM D1238) below about 10, more preferably between about 2-6.
Other resins besides polypropylene resins include polyethylene as well as copolymers made from monomers comprising ethylene, propylene or other lower aliphatic 20 hydrocarbon monomers such as copolymers of ethylene and propylene. ?
Mica fillers suitable for use in this invention are also commercially available. The mica can be generally characterized as being an aluminum silicate mineral that can ~5 be cleaved into thin sheets. Examples of commercially available mica filler include those normally denominated as muscovite, biotite and/or phlogopite micas. Mica filler comprising principally phlogopite mica as Suzorite mica marketed by Marietta Resources International constitutes a 30 mica that allows formation of molded articles with particularly desirable properties, especially when compounded as herein.
The mica filler comprises thin flakes of mica that are typically made by delamination of mica mineral. Mica, 35 such as that comprising principally phlogopite mica, that is ; retained on a 100 mesh screen, desirably on a 60 mesh screenis preferred and normally mica passing through a 20 mesh - screen can be advantageously processed, although mica that is ; of other size will be suitable. Mica as that sold by ~rQd e ~ ks .' : , . . .
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Marrietta International.as Suzorite* 60-S and.being re~erred to as Imc:lassi~ied with respect to aspect.ratio can yield desirable composites. Measurement of number average aspect ratio (average diame-ter of flakes over average thickness) o~ such mica show them to have low aspect ratio, i.e., below 30, although.higher aspect ratio mica may be employed, e.g. 20-200.
The heat sensitive additive.for which.this invention is particularly advantageous includes chlorinated compounds desirably comprising about 45-85%.by weight chlorine, more preferably about 60-80~ by~weight and espec.ially, chlorinated hydrocarbons such:as waxes marketed as Chlorez*
(Dover Chemical), Chlorowax* (Diamond Shamrock), and Kloro-chek* (Keil Chemical, a division of Ferro Chemical).
Typical molecular weights (weight average) for such chlorin~
ated waxes are between about 500-2000,. and expec.ially between about 1000-1500 with desirable results especially being achieved with waxes having.between about 70-78%
by weight chlorine. .Other chlorinated compounds that may be suitably employed include chlorinated aliphatics with as low as 5~ by weight chlorine and molecuIar weights (weight average) as high as several thausand ~e.g., 10,000).
Prior to compounding at least a portion of the additive is preferably dry contacted with the mica par-ticles to provide a blend. For example, the mica andadditive in powder or other suitable form can.be t~ led together preferably at elevated temperature (to make the additive molten e.g., temperatures preferably between about 60-180C) to yield a coated mica. ~ther information on coating mica with chlorinated additives appears in the aforementioned Canadian patent application Serial No. 297,224):. Normally, the additive and mica will be admixed in this coating process such that the ~additive is added between.about 0.1-15~ (preferably about 1-5%) by weight of the combined mica and additive weight. The raw mica is desirably about 10-80%.by weight of the combined weight of resln and mica.
In another method of making, mica is coated by contacting intimately the mica particles and:additive * Trademarks .. ~
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in liquid carrier such as by di~pe~sing powdered additive with mica and addiny solvent thereto. Canventional solvents, e.g., aliphatic chlorides may be convenienkly used. The latter procedure is described in our copending Canadian patent application Serial No. 339,024 filed November

2, 1979.
The invention is described urther, by way of illustration, with reference to the accompanying drawing, which illustrates a portion of a twin screw extruder, a preferred apparatus for compounding in accor-dance with this invention.
One screw o~ the twin screw extruder is illustrated.
The other screw (not shown) has flights corresponding to flights of the screw illustrated except tha-t the flights are reversed in angle, i~e., the reverse fligh-ts are at the same but negative from normal as the flight angles of the screw shown. The screws are non-intermeshing and counter rotating. The screw not shown is of similar diameter, but shorter by about the length of three diameters ~hereby allowing attachment of the barrel to a conventional strand die orifice.
The drawing illustrates a preferred manner in which compounding is accomplished in accordance with this invention. The device illustrated is one side of a twin screw extruder which is, in preferred mode, operated such that the screws are counter rotating and non-inter-meshing. Such twin screw extruders are commercially available with variable screw configurations from Welding Engineer, Inc.
Melt forming resin such as polypropylene is added to one end of~the twin screw extruder in an area of flight ;~ configuration preferably that subjects it to sufficiently high-shear to cause elevated temperature, e.g. 440F
and to provide a molten mass of resin prior to addition of the mica and additive blend. (By "molten" herein is meant with reference to resin that particles of resin are at a temperature that can ~or does) provide their coalescence with one another). Initially, the barrel of the extruder at this area may be heated to maintain , :

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s 7a its temperature in a range above about 400F, preferably about 420-460F. During extended use, however, this area is maintained by conventional means at desired pro-cessing temperature, e.g. 435-455F.
The coated mica is thereafter introduced into the molten resin through one or more ports downstream as illustrated in the drawing. Essential to the addition of blended mica and additive particulate is its reduced shear mixing with the molten melt forming resin so as to maintain temperature control. It is found that high shear mixing as in many conventional extruders causes such work on the mica particles as to cause an uncontrollable temperature rise when compounded at very high speeds e.g., 600 lb/hr. or higher. This temperature rise markedly reduces the efficiency of the heat sensitive additives and in one case, e.g. Chlorez (Dover Chemical) with about ~4~ by weight chlorine causes significant ,~
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deterioration, at temperatures above about 480F.
In order to obtain maximum effect of the additive in as rapid as possible time, the temperature of the resin prior to mica incorporation is carefully controlled. Additionally, the shear applied to the resin is controlled so as to insure that the melt index (ASTM D1238) is preferably maintained below 15 and preferably below 12 or even 10 for most product ¦
applications. Thus, the amount of shear that is applied to the resin (prior to mica incorporation) is that amount which 10 does not significantly elevate its melt index but which does provide a temperature high enough for rapid and effective incorporation of mica and additive. Such temperature or "initial mixing temperature" is preferably in a range that is not lower than about 60F below a temperature which would 15 cause evolution of chlorine containing gas from the additive by thermogravametric analysis. More preferably, such initial mixing temperature is not lower than about 25F below that temperature. (Well known thermogravimetric analysis techniques for determination of a temperature of first 20 evolution of chlorine containing gas (i.e. outgassing of the additive) may be used. For example, Chlorez 700 from Dover Chemical and having about 74% by weight chlorine in the wax outgas~es at about 480F).
The resin, however, prior to mica and additive 25 incorporation may be at a temperature above the temperature at which there would be outgassing from the additive. This is because incorporation of mica into the resin first provides some cooling to the resin. Thus, for example, at especially high loadings of mica, e~g. 50%-75% or more, even higher initial temperatures for the resin may be tolerated or even advantageous. For most circumstances, however~ the initial temperature of the resin is desirably between about 10-60F
below that temperature at which there would be outgassing of the additive. ~
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'' : . : -_9_ The temperature at which mica and resin ~ix should preferably not be allowed to reach a temperature about 25F, more preferably 15F higher than the initial mixing temperature of the resin. Additionally, such temperature should be in a range below that temperature at which chlorine containing gas evolves from the additive. Such a temperature range is accomplished by low shear kneading of the mica particles into the resin. Cooling of the extruder during mica - incorporation into the resin may be used.
As previously noted, it is particularly de~irable that the melt index of the resin not exceed about 15 (ASTM
D1238). In other product applications, however, a higher ~elt index may be useful. In such a circumstance, very high shear or~ in some circumstances, chemical additives (e.g. peroxides) 15 may be used to provide products (e.g. pellet~) at a melt index of 20 or higher.
As mentioned, it is preferred to use twin screws that are counter-rotating, and desirably the twin screws are non-intermeshing as are available commercially. By adding the 2Q mica into a turbulence created between counter rotating streams of molten resin created by such devices good ini~ial ; mixing, is obtained.
Various flight changes as illustrated in the drawing during passage of the resin as well as resin and mica through the above described twin screw extruder can al.so be of advantage to promote mixing as will be understood by ~hose in the art. As there are matters within the skill of the art, no ~urther description is believed necessary. As previously mentioned, however, the amount of shear applied is such that its melt index (ASTM D1238) is not elevated above about 15, more prefexably 12.
As shown in the drawing, it is advantageous to draw a vacuum from the extruder, preferably, as shown, downstream from mica addition. Such vacuum may be desirably, for example, in the range of about about 15 inches of Hg, more preferably about 20 inches Hg as 22 inch Hg. Such .
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vacuum removes entrapped gases as air or volatiles developed during compounding.
The extruder may be fitted at the end, for example, with a conventional strand die (not shown) to yield strands that are cooled and diced into composite molding precursors, e.g. pellets. Moreover, the extruder may also be connected to shaping devices that take strands or other molding precursors and shape them into desired object. Furthermore~ if desired, the extruder may be fitted with extensions as heated pipes that provide additional time for interaction of the mica and melt forming resin.
Advantageously, however, as mentioned, the entire compound extrusion provides a melt residence, i.e. time that mica and melt forming resin and additive exist in melt form of less than about 30 seconds, more usually less than about 15 seconds. Although additional melt residence is provided by further molding activities, e.g. injection molding, pellets compounded in the manner described can provide molded articles of excellent properties under standard shaping conditions.
The mica in this invention may be replaced in part 7 as is understood, by other particulates, e.g. talc, glass, calcium carbonate and the like to provide desired modifications, such particulates being added with, for example, the mica or at other convenient processing times.
The following examples are intended to illustrate the invention in currently preferred aspects and should not therefor be interpreted as necessarily limiting the scope thereof for those in the art will recognize other readily apparent modifications within the hereinbe~ore disclosed invention. As used in these examples as well as used in the hereinbefore description and hereinafter appended claims, melt index is grams per 10 minutes.

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Using a Welding Engineers 2.0" Twin-Screw Extruder, equal parts by weight of Gulf Polypropylene 6420 MHP and coated mica are compounded. The mica is combined with Chlorez 700 by tumbling it with heated mica to yield a coating thereon. The Chlorez 700 is used at a level that would be about 1% by weight of the combined weight of mica and polypropylene. Chlorez 700 (available from DoYer Chemical) has about 74% chlorine by weight, an average molecular weight of about 1250 and a nominal formula indicating one extra chlorine for the number of carbon atoms present. The raw mica is Suzorite 60-S marketed by Marietta International.
The temperature of the extruder is maintained at 440~ and the polypropylene continuously starve fed ~oliowed by continuous starve eeding of the so combined mica and additive particles. The polypropylene has a temperature of about 440F and MHP index below 10 before combined mica and additive particle addition. The twin screws are counterrotating and non-intermeshing and a vacuum of approx.
22 inches is maintained. The resin becomes molten after passage of about 8" along the extruder. The rate of addition yields 600 lb./hr. of compounded product which is sent through a strand die to provide strands about 1/4" or less which are thereafter cooled and diced into pellets. The strands exit the extruder at a temperature of about 450F. The pellets are molded into standard test bars by injecting at 600 psi and 428F. The properties of the test bars are as follows:
Properties ASTM 50~ Mica/PP
Method Tensile S~rength, PSI D638-72 4,830 Tensile Elongation ~ D638-72 1~02 Flexural Strength, PSI D790-71 7,790 Flexural Modulus, PS~ D790-71 1,275,000 Deflection Temperature D648-72 lzod Impact, Ft./lbs./in. B256-73 Notched ,59 Unnotched 2~00 Specific Gravity D792-70 10375 Mold Shrinkage. D955 (F) .0016 (T) .0018 The elapsed time between introducing a portion of the resin and its exiting in the strands from the extruder is within 15 seconds~

The procedures of Example 1 are followed except for replacement of a section of the screws that melt the resin prior to incorporation of the mica. This section provides very high shear to the resin and imparts to the resin a melt index of above 20. The filled resin has similar properties to those listed in Example 1 but exhibits bri~tleness.

The procedures of Example 1 are followed except ~hat 20 the mica is coated with a solution of Chlorez 700 in methylene chloride. Essentially comparable results are obtained.

EXAMP~E 4 .. . .
The procedures of Example 1 are followed e~cept that 25 the temperature of the extruder is maintained at about 450F
and the strands exit at about 460F. Similar results are obtained.

The pellets of Example 1 are molded by injection molding at 440F at llOO psi into a mold maintained at 120F
to yield a crash pad retainer suitable for automotive application. The retainer is flame treated prior to its contact with a polyurethane precursor and the precursor foamed 35 between the retainer and vinyl sheet to provide a mica and polypropylene/foam/vinyl laminate.
~', t ,~", ''' ", 5~3~5 The procedures of ExaMple 1 are followed except that the chlorinated wax comprises Chlorowax 70, marketed by Dia~ond Shamrock. Similar resu~ts are obtained.

The procedures of Example 1 are followed except that the mica is introduced in equal parts by weight into two different ports, the second being downstream from the first.
Essentially similar results are obtained.

. EXAMPLE 8 .
The procedures of Example 1 are followed except that the weight proportions of resin and coated mica particles are

3:2 respectively. Molded test bars show excellent properties.

The procedures of Example 1 are followed except that the melt forming resin contains calcium carbonate.

Thè procedures of Example 1 are followed except that the coated mica is added to yield pellets that comprise 5% by weight mica.

The procedures o Example 1 are followed except that the weight ratio of coated mica to melt forming resin is 2:1.

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Prior to compounding with the resin, the additive may be, rather than coated on the mica, or in addition to being coated on the mica, dry blended with the mica as follows:

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EXAMP~E 12 Using a Welding Engineers 2.0" Twin Screw Extruder as - illustrated in the ~rawing, equ~l parts by weight of Gulf Polypropylene 6420 MHP and mica ~with particulate additive) are compounded. The mica is blended with Chlorez 700 by tumbling it at room temperature in a ribbon blender for fifteen minutes~ The Chlorez 700 is used at a level that would be about 1% by wei~ht of the combined weight of mica and polypropylene. Chlorez 700 (available from Dover Chemical~
10 has about 74~ chlorine by weight, an average molecular weight of about 1250 and a nominal formula indicating one extra chlorine for the number of carbon atoms present. The raw mica is Suzorite 60-S marketed by Marietta International.
The temperature of the extruder is maintained at 15 440F and the polypropylene continuousIy starve fed followed by continuous starve feeding of blended mica and additive particulate. The twin screws are counterrotating and non-intermeshing and a vacuum of approx. 22 inches is maintained. The resin becomes molten after passage o~ about 20 8" along the extruder. The rate of addition yields 600 lb./hr. of compoun~ed product which is sent through a strand die to provide strands about 1~4" or less which are thereafter cooled and diced into pellets. The strands exit the extruder at a temperature of about 450F. The pellets are molded into 25 standard test bars by injecting at 600 psi and 428F~ The properties of the test bars are as follows:
_ opertie_ Dry Mixed Mica Strength (psi) x 5,760 s 130 # 5 Tensile Elongation (%) x N.A~
S N,A.
# N.A.

5~3~5 Strength (psi) x 8,390 - # 5 Flexural Modulus (psi) x 1,350,00 s 20,000 ~ 5 264 psi (F) x 276 - s ~ 2 Heat Deflection Tempe~rature 66 psi (F) x 302 s 2 # 2 Notched (ft./lb./in.) x O39 s .00 Izod 20 ImpactUnnotch (ft./lb./in.) x 1.15 s 0 9 N.A. - Not Available x z Mean s = 5tandard deviation - Number of test samples The elapsed time between introducing the resin and exiting of the strands from the extruder is within 15 seconds.

30EXAMPLE 13 ~
The procedures of Example~ 1 are foll~wed except that - the mica is blended with twice as much Chlorez 700.
Essentially comparable results are obtained.

35The procedures of Example l are followed except that the temperature of the extruder is maintained at about 450F

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and the strands exit at about 460F. Similar resul~s are obtained.

The pellets of Example 12 are molded by injection molding at 440F at llO0 psi into a mold maintained at 120F
to yield a crash pad retainer suitable for automotive application. The retainer is flame treated prior to its contact with a polyurethane precursor and the precursor foamed between the retainer and vinyï sheet to provide a mica and ~0 polypropylene/foam/vinyl laminate.

The procedures of Example 12 are followed except that the chlorinated wax comprises Chlorowax 70, marketed by Diamond Shamrock. Similar results are obtained.

EXAMPLE_17 The procedures of Example 12 are followed except that the blend of mica and additive is introduced in equal parts by weight into two different ports, the second being downstream from the first. Essentially similar results are obtalned.
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EXAMPLE lB
The procedures of Example 12 are followed except that the weiyht proportion of resin and mica is 3:2 respec~ively.
Molded test bars show excellent properties.

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Claims (11)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows

1. A continuous method for rapidly compounding mical additive and melt-forming resin made from monomers comprising olefinic hydrocarbon monomers wherein the mica is intimately admixed with heat-sensitive additive comprising chlorinated hydrocarbon wax to form a particulate blend, which method comprises:
(A) subjecting the resin to high shear to provide a molten mass comprising the resin;
(B) contacting the molten resin with the blend comprising intimately admixed mica and chlorinated hydro-carbon wax at a temperature below that at which chlorine containing gas would evolve from the additive;
(C) kneading the molten resin and the blend at low shear to provide a mixing thereof.

2 The method of claim 1, wherein the melt-forming resin comprises polypropylene and the chlorinated wax comprises about 65 to 80% by weight chlorine.

3. The method of claim 2, wherein the mica comprises phlogopite mica.

4. The method of any one of claims 1, 2 or 3, wherein the upper temperature during compounding is below about 480°F.

5, The method of any one of claims 1, 2 or 3, wherein the molten mass of resin comprises at least two counter-rotating streams of the resin that contact one another.

6 A continuous method for compounding, at elevated temperature in less than about 30 seconds, mica, heat-sensitive additive and melt-forming resin made from monomers comprising olefinic aliphatic hydrocarbon monomers wherein the heat-sensitive additive comprises a chlorinated hydro-carbon wax comprising about 65 to 80% by weight chlorine, which method comprises:
(A) subjecting the resin to high shear to form molten resin;
(B) providing at least two streams of said molten resin having a melt index (ASTM D1238) below about 15 that are counter-rotating with respect to one another ane contact one another to provide a turbulence therebetween, the molten resin being at an initial mixing temperature in a range which is not lower than about 60°F below that temperature at which chlorine containing gas would evolve from the additive;
(C) introducing into the turbulence particulates comprising the mica intimately admixed with the additive comprising chlorinated hydrocarbon at a temperature below that at which chlorine containing gas would evolve from the additive' and (D) kneading the resin and particulates at low shear to provide a mixing thereof at a temperature which below that temperature at which chlorine gas would evolve from the additive.

7. The method of claim 6, wherein the resin comprises polypropylene and the additive comprises chlorinated wax having about 70 to 78% by weight chlorine,

8, A method of compounding mica and polypropylene resin with heat-sensitive additive that assists in strength-ening composites made comprising mica and the resin and which permits rapid attainment of molding precursors that yield molded articles under conventional conditions and are strengthened by the heat sensitive additive, which method comprises:
(A) subjecting the resin having a melt index (ASTM D1238) between about 2 and 15 at high shear to provide a molten mass comprising the resin at an initial mixing temperature in a range between about 25°F below and 60°F below that temperature at which chlorine gas would evolve from the additive;
(B) contacting the molten mass with particulates comprising intimately admixed mica and an additive comprising chlorinated hydrocarbon wax at a temperature below that at which chlorine containing gas would evolve from the additive; and (C) kneading with low shear the particulates and resin to provide a mixing thereof at a temperature which is in a range up to about 25°F higher than the initial mixing temperature and at a temperature below that at which chlorine containing gas would evolve from the additive.

9. A continuous method for compounding at elevated temperature in less than about 30 seconds, mica and melt-forming resin made from monomers comprising olefinic aliphatic hydrocarbon monomers wherein the mica has a coating made by contacting the mica particles with a heat sensitive additive comprising a chlorinated hydrocarbon comprising about 65 to 80% by weight chlorine, which method comprises:
(A) subjecting the resin having a melt index (ASTM D1238) below about 15 to high shear to form molten resin;
(B) providing at least two streams of said molten resin that axe counter-rotating with respect to one another and contact one another to provide a turbulence therebetween, the molten resin being at an initial mixing temperature in a range which is not lower than about 60°F below that temperature at which chlorine containing gas would evolve from the additive;
(C) introducing the coated mica into the turbulence at a temperature below that at which chlorine containing gas would evolve from the additive; and (D) kneading the resin and mica. at low shear to provide a mixing thereof at a temperature which below that temperature at which chlorine gas would evolve from the additive.

10. The method of claim 9, wherein the resin comprises polypropylene and the additive comprises chlorinated wax.

11. A method of compounding mica and polypropylene resin with heat sensitive additive comprising chlorinated aliphatic compounds that assist in strengthening composites made comprising mica and the resin and which permits rapid attainment of molding precursors that yield molded articles under conventional conditions and are strengthened by the heat sensitive additive, which method comprises:
(A) subjecting the resin having a melt index (ASTM D1238) between about 2 and 15 to high shear to provide a molten mass comprising the resin at an initial mixing temperature in a range between about 25°F and not more than about 60°F below that temperature at which chlorine gas would evolve from the additive, (B) contacting the molten mass with the mica at a temperature below that at which chlorine containing gas would evolve from the additive, said mica having a coating made by contacting mica particles and the additive and (C) kneading with low shear the mica and resin to provide a mixing thereof at a temperature which is in a range up to about 25°F higher than the initial mixing temperature and at a temperature below that at which chlorine containing gas would evolve from the additive.