WO2006026572A2

WO2006026572A2 - Masterbatches and methods to improve masterbatch compounding

Info

Publication number: WO2006026572A2
Application number: PCT/US2005/030720
Authority: WO
Inventors: Gerald F. Brem; Nicholas L. Tartaglione
Original assignee: Hi-Tech Environmental Products, Llc
Priority date: 2004-08-31
Filing date: 2005-08-30
Publication date: 2006-03-09
Also published as: WO2006026572A3

Abstract

Masterbatch compositions and methods for the production of same using predominantly amorphous natural or dominantly amorphous synthetic aluminosilicate include a polymer with milled natural aluminosilicate having at least a predominantly amorphous structure or a synthetic aluminosilicate with a dominantly amorphous structure at about 17-50% by weight of the resulting compound. The master batches also include about 0 to 50% by weight of the resulting composition being filler or functional additives. The methods for creating a masterbatch are contemplated to include compounding the composition by maximizing output efficiency as determined by output weight per kilowatt-hour with aluminosilicate, filler and functional additives compounded with fusible polymer.

Description

MASTERBATCHES AND METHODS TO IMPROVE MASTERBATCH

COMPOUNDING

CLAIM OF PRIORITY Priority is claimed to U.S. Provisional Application No. 60/606,543, filed

August 31 , 2004.

BACKGROUND

The field of the present invention is masterbatch compositions for fusible polymers and methods of masterbatch compounding. Polymers such as thermoplastics, thermoplastic elastomers and thermoplastic vulcanizates are used in an immense number of products worldwide. In part, the products are made of polymers because of reasonable manufacturing costs, but in many instances polymers are chosen because of their variety in properties such as color, strength, durability, weight, chemical resistance or tactile feel.

A variety of polymer properties is desirable for polymer articles, but not for the base polymer manufacturers. Polymer manufacturing plants are expensive to build, maintain and operate. To gain economy-of-scale benefits in a highly competitive worldwide polymer market, polymer manufacturers mass produce relatively simple base polymers appropriate for a broad market.

The limited range of mass-produced base polymer properties has resulted in an increasingly important industry — secondary polymer processors, referred to as compounders. Compounders modify the base polymer properties to meet requirements for specific applications by combining the base polymer with fillers and functional additives such as pigments, reinforcing agents, stabilizers, flame retardants, impact modifiers, plasticizers, nano-composites, etc. The additive types are extremely diverse, not only because of differing effects on the base polymer but also because different base polymer compositions require different additives to achieve the same effect. In general, additives may be in the form of solid particles, liquids or gases when being compounded into the base polymer; however, additives in a solid form during compounding are of particular interest here. To be most effective, additives must be fully dispersed (encased in host polymer) and distributed (equal concentration per unit volume) throughout the polymer. Dispersion and distribution of the additives into a polymer are typically achieved by blending of the additives and polymer melt in specially designed compounding equipment. The melt blend is then rendered into a cooled, solid form of a pellet, chip, flake or powder suitable for finished product manufacture.

For some applications and some polymer formulations, additives are directly compounded into the polymer used to manufacture the article. For many applications, however, a second method is more desirable and is of particular interest herein. It is possible to make a masterbatch (also referred to as color masterbatch or concentrate) with a high concentration of filler or functional additives dispersed into a carrier polymer, a binder polymer or mixture of polymers that are the same composition as or are a composition compatible with the polymer in the finished product. The masterbatches are typically made into a physical form (pellet, flake, chip, etc.) suitable for "let down" (added at a low concentration) at a rate of 1-10% by weight of the resulting composition. For example, a concentrate with 25% by weight of an additive that is let down at 1% by weight into the final polymer will have a resultant concentration of 0.25% (1 % of 25%). If the finishing method properly distributes additives previously dispersed in the masterbatch, the polymer in the finished article will have properties as if the additives were directly compounded into the base polymer.

There are several important advantages to use of a masterbatch. From a practical standpoint, incorporating 1% of a masterbatch pellet or chip with 25% of an additive is technically less difficult than incorporating 0.25% of the same additive in the form of a fine powder. Furthermore, the masterbatch may contain multiple additives. Distribution of additive(s) compounded into a pellet or chip in the base polymer is likely to be improved because the additive(s) is already dispersed into the carrier polymer and only requires distribution in the finishing process. From an economic standpoint, masterbatches are desirable because it is less expensive to compound additives into a relatively small amount of masterbatch rather than directly into the entire polymer mass.

As with most manufacturing processes, advantages are coupled with disadvantages. For masterbatches, a high concentration of solid particles decreases the output rate and increases the energy required to produce a unit of masterbatch in commonly used compounding equipment characterized by a continuous product output such as single-screw extruders, twin-screw extruders, continuous mixers, or combinations thereof. The decrease in output and increase in energy consumption (or a decrease in processing efficiency as measured by product output in pounds per kilowatt-hour of energy) clearly detract from some of the advantages of using masterbatches as compared to direct compounding.

Compounders have tried numerous methods to improve manufacture of masterbatches with high solids concentrations; however, for each method that provides an advantage there is a corresponding disadvantage. Increased melt temperature may increase processing efficiency but may also increase the likelihood of decreased additive dispersion, degradation of polymer or additive, or increased energy consumption. More powerful drive motors may increase rotational speed and output, but may result in increased viscous dissipation of energy into the polymer or may result in breakdown of the polymer molecular structure. Use of a carrier polymer with a lower molecular weight and lower melt viscosity for additives may increase processing efficiency, but may also adversely impact physical or cosmetic properties of the finished polymer. Internal and external lubricants can result in improved concentrate production, but the lubricants become part of the finished polymer and may have serious adverse effects on cosmetic appearance, long-term stability, adherence of paint or metal plating, or physical properties.

There is an industry-wide desire for methods to improve the manufacture of masterbatch compounds centered on: (1) increasing the efficiency of manufacture as measured by output rate and/or energy consumption per weight produced; (2) reducing the cost of masterbatch compounds by utilizing lower concentrations of functional additives to achieve the same effect when let down into the finished polymer; (3) utilizing common compounding equipment with little or no modification; (4) being chemically inert with respect to other additives and base polymer; and (5) maintaining or improving the physical properties of the base polymer after addition of the masterbatch during manufacture of finished articles.

One additive, natural aluminosilicate with at least a predominantly amorphous structure (referred to as natural aluminosilicate glass herein where the minority component, typically less than about 20 percent by weight, is crystalline minerals), has been available for amending the viscosity of thermoplastics. The additive and its employment are disclosed in U. S. Patent 6,921 ,789 to Jess Booth et al. entitled SYNTHETIC THERMOPLASTIC COMPOSITION ARTICLES MADE THEREFROM AND METHOD OF MANUFACTURE, the disclosure of which is incorporated herein by reference. The natural aluminosilicate glass with an amorphous content of more than 93 percent by weight and a synthetic aluminosilicate with a dominantly amorphous structure (referred to as synthetic aluminosilicate glass herein) has been available for amending the viscosity of thermoplastics, thermoplastic elastomers and vulcanizates and thermoset polymers. The additives and their employment are disclosed in U.S. Patent Application to John Barber et al. entitled ADDITIVES FOR USE IN POLYMER PROCESSING AND METHODS OF PREPARATION AND USE THEREOF, U.S. S.N. 10/643,528 filed 8/19/03, the disclosure of which is incorporated herein by reference. Natural aluminosilicate glass and synthetic aluminosilicate glass are referred to collectively as aluminosilicate glass herein.

SUMMARY OF THE INVENTION

The present invention is directed to masterbatch compositions and methods for the production of same using predominantly amorphous natural or dominantly amorphous synthetic aluminosilicate.

In a first separate aspect of the present invention, masterbatches are contemplated to include a polymer with milled natural aluminosilicate having at least a predominantly amorphous structure or a synthetic aluminosilicate with a dominantly amorphous structure at about 17-50% by weight of the resulting compound with about 0 to 50% by weight of the resulting composition being filler or functional additives. The aluminosilicate is included in an amount to increase processing efficiency.

In a second separate aspect of the present invention, the fillers or functional additives in the masterbatches of the first separate aspect may be selected from the group consisting of pigments, reinforcing agents, stabilizers, flame retardants, impact modifiers, plasticizers and nano-composites. In a third separate aspect of the present invention, the methods for creating a masterbatch are contemplated to include compounding the composition by maximizing output efficiency as determined by output weight per kilowatt-hour.

Again, aluminosilicate with filler and functional additives are compounded as above with the fusible polymer.

Accordingly, it is an object of the present invention to provide novel masterbatches and methods of compounding such masterbaches. Other and further objects and advantages will appear hereinafter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiment is directed towards addition of below about 17 to 50 percent by weight of the resulting composition of aluminosilicate glass particles to a polymeric liquid that contains 0 to 50 percent by weight of fillers and functional additives. The glass particles are comprised of milled natural aluminosilicate with at least a predominantly amorphous structure or milled synthetic aluminosilicate glass with a dominantly amorphous structure. The particles range in size from about 2 to 75 microns in maximum dimension as measured by laser-diffraction spectroscopy. The mixture of aluminosilicate glass, fillers and functional additives and polymeric liquid is processed into a masterbatch by using compounding equipment with continuous product output such as a single-screw extruder, twin-screw extruder, continuous mixer, or combinations thereof. The compounded mixture is rendered into a cool, solid form of a pellet, chip, flake or powder suitable for addition at a rate of 1-10 percent by weight of the resulting composition into a base polymer appropriate for the finished article. A method to employ the aluminosilicate glass bearing composition for masterbatch production includes: non-intuitive adjustments to melt temperature, screw or rotor rotational speed and feed rate of the masterbatch compounding equipment. Such adjustments can substantially improve masterbatch processing efficiency (defined by an increase in product output in pounds divided by the energy consumption in kilowatt-hours) as compared to processing masterbatch with up to about a 50 weight percent concentration of filler or functional additives such as pigments, reinforcing agents, stabilizers, flame retardants, impact modifiers, plasticizers, nano-composites, etc.

Masterbatch compounds typically contain moderate to high (10-80 percent by weight) concentrations of fillers or functional additives in order to have a concentration appropriate for their desired effect when diluted by let down into the finished base polymer. The high concentration of fillers or functional additives, while necessary for modifying the base polymer properties, decreases masterbatch processing efficiency, most likely due to an increase in polymeric liquid viscosity. As a general rule, masterbatch processing efficiency decreases proportionately with increasing filler and functional additive concentration.

Particles of natural aluminosilicate glass and synthetic aluminosilicate glass, are prepared to specifications in Barber et al. (U.S. Patent Application S.N. 10/643,528). These particles when added to a masterbatch have an unanticipated effect on processing efficiency. At concentrations of 17 to 50 weight percent of the resulting composition, addition of aluminosilicate glass particles to a polymeric liquid containing up to 50 percent by weight of fillers and functional additives increases masterbatch processing efficiency. Indications are that the concentrations may be effective at below about 17 weight percent.

Aluminosilicate glass is a preferable material because it is chemically inert with respect to polymers and additives. High-resolution nuclear magnetic resonance spectroscopy of a linear low-density polyethylene (LLDPE) masterbatch was unable to detect any chemical change to the polymer composition after compounding with 50 weight percent aluminosilicate glass particles. Aluminosilicate glass particles are effective in every polymer composition investigated and do not alter the crystallization of semicrystalline polymers. Furthermore, when the masterbatch is let down at typical rates of 1-10 percent by weight, the aluminosilicate glass particles have no substantive effect on the cosmetic, physical or performance properties of the finished polymer.

In one example, natural aluminosilicate particles with a maximum particle size of about 75 microns were added at a 50 percent concentration by weight of the resultant composition to a LLDPE that was being compounded on a 92-mm twin-screw extruder. The response was entirely unanticipated. Instead of decreased output and increased die head pressure, the output of the extruder increased dramatically and the head pressure decreased so much that the low- pressure alarm shut down the extruder. In this particular instance the combination of melt temperature, screw rotational speed and feed rate was balanced such that the masterbatch with aluminosilicate glass particles was transported by the screws and extruded from the die at such a high rate, pressure at the die head was inadequate for safe operation of the extruder. A reduction in polymeric liquid viscosity is strongly suspected because of the low die head pressure. Subsequently, the masterbatch was successfully compounded by lowering the melt temperature and increasing the feed rate as compared to compounding of LLDPE with high concentrations of solid particles such as calcium carbonate filler. Changes in operating parameters for compositions with aluminosilicate glass are not intuitive because production of masterbatch with high concentrations of solid particles other than aluminosilicate glass typically require an increase in melt temperature and/or screw speed to maintain or increase output. In another example, a 50:50 masterbatch of natural aluminosilicate glass with a maximum particle size of about 19 microns and LLDPE was attempted on a continuous mixer using "standard" operating parameters selected for efficient production of masterbatches without aluminosilicate particles. The results were unacceptable in that the pelletized masterbatch with aluminosilicate particles was filled with voids and had poor dispersion and distribution of the aluminosilicate particles. New operating conditions had to be established — reduced melt temperature and reduced rotor rotational speed — before acceptable masterbatch could be produced. The feed rate to the continuous mixer with the adjusted operating parameters was gradually increased to over 250 Ibs/hr, a rate nearly 150 percent higher than the "standard" limit for preparation of masterbatch without aluminosilicate particles. As might be expected, the amperage draw of the continuous mixer increased, but only by 50 percent. The larger increase in output rate relative to the increase in energy demand clearly indicates improved processing efficiency. At the same time, the screw RPM in the downstream single-screw extruder was increased to keep up with the output from the continuous mixer. Even though the screw RPM had to be increased to compensate for the increased continuous-mixer output, the amperage draw on the extruder decreased from 17 to 12 amps. The increased output rate and lower energy consumption rate for the single-screw extruder clearly indicated a greater processing efficiency.

In a third example, a 25 weight percent concentration of natural aluminosilicate particles in the resulting composition were added to a color masterbatch composed of PET containing about 25 percent by weight of organic pigments. Compounding of the color masterbatch with aluminosilicate particles at "standard" but efficient operating conditions for the color masterbatch lacking aluminosilicate particles was unsuccessful. The masterbatch contained voids filled with trapped volatiles and the pigment particles appeared to be poorly dispersed and distributed. To effectively compound the color masterbatch with aluminosilicate particles, the screw RPM on the 27-mm twin-screw extruder had to be reduced by about 25 percent and the barrel temperature reduced by about 3O⁰C. A vacuum vent was employed to remove excess volatiles. Under these processing parameters, the screw motor was operating at about 29 percent of maximum torque as compared to 40-50 percent when compounding of the color masterbatch without aluminosilicate particles. No attempt was made to increase the feed rate or output rate; however, the decrease in motor torque and consequently power consumption clearly indicates an increase in processing efficiency. In another example, a 17 weight percent concentration of aluminosilicate particles in the resulting composition was added to a color masterbatch of a proprietary carrier polymer and black pigment with binder polymer. The melt temperature was selected to be at the lower end of the range recommended for the polymer and was not adjusted. Based on prior experience with aluminosilicate-bearing masterbatch compounds, the screw RPM was lowered by about 30 percent from efficient processing parameters for a color masterbatch without aluminosilicate particles. The feed rate was adjusted for the maximum output rate of a high-quality product for formulations without and with aluminosilicate particles at the lower rotor speed. By adding the aluminosilicate particles, the output rate was maximized at a rate at least 47 percent higher than that achievable without aluminosilicate particles and the amperage demand of the motor decreased from 28 to 17. The combined increase in output and decrease in energy demand clearly indicates a substantial improvement in processing efficiency as compared to color masterbatch without aluminosilicate particles (either at the same RPM setting or at the higher setting deemed by the operator as being most efficient). These results are even more remarkable because the amount of polymer in the color masterbatch with aluminosilicate particles was reduced as compared to the color masterbatch without aluminosilicate particles. The polymer concentration had to be reduced in the formulation with aluminosilicate particles to make "room" for the aluminosilicate particles while at the same time preserving a constant amount of pigment delivered to the target polymer when the color masterbatch was let down at 3 percent. The quality of the color masterbatch with aluminosilicate particles was so superior to the standard color masterbatch without aluminosilicate particles the pigment concentration was reduced about 20% in the color masterbatch with aluminosilicate particles with no adverse effect on finished polymer color.

Clearly, masterbatch formulations that include solid particles of aluminosilicate glass are compounded more efficiently at higher rates and/or with lower energy per pound produced than masterbatch formulations without the glass particles. Although some increase in production rate of masterbatch with glass particles can be attributed to the greater density due to replacement of polymer (density of about 1.0 gm/cm³) by glass (about 2.3 gm/cm³), the output increases are clearly more than those due to density increases alone and decreases in energy demand cannot be ascribed to increased polymer density. Clearly, aluminosilicate glass particles have altered the polymeric melt properties in a manner that allows for increased output and/or decreased energy consumption. Higher throughput from continuous-output compounding equipment suggests more efficient transport of the polymeric melt by the screws or rotor which may, in turn, indicate a beneficial change in the coefficient of dynamic friction between the melt, screw or rotor flights and barrel of the compounding equipment. Increased output rates accompanied by lower die head pressure and/or lower power demands per weight of polymer strongly suggest that the viscosity of the polymeric melt with aluminosilicate glass particles is lower. The discussion below focuses on polymeric liquid viscosity because some of the changes can be quantified; however, beneficial changes in dynamic friction between the melt and flights of the screw or rotor and barrel may be an additional important factor in determining output rate and compounding efficiency.

An upper concentration limit of about 50 percent by weight of aluminosilicate glass particles in the resulting composition is reasonably well defined. This appears to be the maximum amount that can be compounded into shear-insensitive polymers such as polyolefins. For polymers such as ABS, which are more shear sensitive, the practical limit is about 25 percent. At higher concentrations, the ABS polymer chain breaks down under shear stresses. For other polymers, the upper concentration limit is determined by onset of declining dispersion and distribution of solid particles in the polymeric liquid as the solid concentration is increased. It is anticipated that the upper limit of aluminosilicate particle concentration will vary from about 25 to 50 percent depending on the polymer composition, concentration of fillers and functional additives, and characteristics of the compounding equipment. A lower concentration limit of 17 percent of aluminosilicate glass particles is not well defined. It is known that about 0.75% by weight of aluminosilicate particles in a polymer reduces the melt viscosity and improves the output and efficiency of direct compounding of additives into base polymers as well as single- and twin-screw extrusion molding of polymers (Barber et al.). Increasing the concentration of aluminosilicate particles to more than about 1.0% by weight results in an increase in melt viscosity and loss of output and processing efficiency. At about 2% by weight concentration, there are no viscosity, output or efficiency benefits remaining as compared to polymer melt with no aluminosilicate particles. However, a 17% by weight concentration of aluminosilicate particles has a distinct benefit in reducing melt viscosity and increasing output and efficiency of compounding equipment. The magnitude of the benefit at 17% by weight is substantial. This suggests that lower concentrations will also provide benefits; however, the lowest concentration at which benefits are present is unknown. A particle size range of about 2-75 microns for the aluminosilicate glass particles is reasonably well established. A maximum particle sizes range of up to about 75 microns appears to be a practical limit more than a limit of particle effect on viscosity. Studies have shown that the rate of abrasion on polymer processing equipment increases rapidly with increasing particle size and with particle concentration. At the high particle concentrations preferred herein, particles coarser than about 75 microns will result in accelerated abrasion rates even in processing equipment with hard chrome wear surfaces. If coarser particle sizes were to be used, they would require costly abrasion-resistant metals that could rarely be justified by a cost-sensitive compounding industry.

A lower particle size diameter of about 2 microns for the aluminosilicate glass particles is based on less direct evidence, but is nevertheless reasonable. Processing engineers with decades of experience in compounding high solid concentrations into polymers have stated that particles less than 2 microns in diameter appear to increase polymer melt viscosity more on a weight-equivalent basis than do coarser particles. Intensive study of low concentrations (less than 2 percent) of aluminosilicate particles in polymer liquids have demonstrated that the most significant viscosity reductions occur when the particles have a size range between 5 and 15 microns. Particle size distributions with maximum diameters less than 5 microns and more particularly less than about 2 microns have far less effect on the viscosity (Barber et al.). The viscosity changes at low concentrations of aluminosilicate particles are attributable to physical interactions of solid particles with polymer molecules and it is clear that the interaction at high concentrations is also a largely physical phenomenon. Therefore, it is reasonable that minimum particle sizes established at low concentrations could very well apply at high concentrations. And as a practical matter, the processing technology used to make the aluminosilicate glass additives creates less than about 6 percent of particles with diameters less than 2 microns. With exception of a fortuitous selection of operating parameters

(temperature, feed rate and screw or rotor RPM) as in the first example above, addition of aluminosilicate glass particles to masterbatch compounds typically will not result in immediate, unassisted improvements in the processing efficiency of continuous-output compounding equipment. Although we cannot provide a detailed mechanism explaining how a high concentration of aluminosilicate particles modifies the viscosity of the melt and/or changes the efficiency of melt transport through the barrel region, we have a process for determining new and substantially different operating parameters to improve masterbatch compounding. These changes are not intuitive. Traditionally, compounders increase the temperature and screw or rotor RPM to increase the output rate. However, as described below, these widely accepted axioms do not uniformly apply to masterbatch formulations with high concentrations of aluminosilicate particles.

Establishing operating parameters of feed rate, screw or rotor RPM and temperature of melt and equipment for efficient masterbatch compounding can be very time consuming, particularly for new masterbatch formulations or new equipment. Although formulations with aluminosilicate particles can result in significant improvements to masterbatch compounding efficiencies, protracted and costly establishment of new operating parameters are rarely needed. Typically, masterbatch formulations with aluminosilicate particles are compounded initially using operating parameters comparable to those for the masterbatch formulation without aluminosilicate particles. Operating parameters are then modified, often in a non-intuitive manner, to improve masterbatch production efficiency.

The melt temperature is a significant factor in determining masterbatch compounding efficiency. The melt temperature may be adjusted from standard temperature prior to compounding of the masterbatch with aluminosilicate particles. Initial efforts to compound masterbatches with aluminosilicate glass particles, as described above, were not successful because the melt temperature was the same as that used for a masterbatch without aluminosilicate particles. The aluminosilicate-bearing masterbatch quality was deemed unacceptable because of retained volatiles and poor dispersion and distribution of additives. The presence of aluminosilicate particles apparently modified the rheologic and frictional properties of the polymeric liquid sufficiently such that mixing of the various components was incomplete and the volatiles were incompletely released. An operator with ordinary skills would traditionally attempt to correct the observed masterbatch defects by increasing the melt temperature, thus lowering the viscosity and presumably improving dispersion, distribution and volatile release. In formulations with aluminosilicate particles, this typical reaction would make the problem worse. The masterbatch quality problem is solvable only by taking the non-intuitive step of lowering the melt temperature. As a general guide, masterbatch processing with aluminosilicate particles is done at the low to middle part of the recommended processing temperature range for the particular polymer composition. Polyolefins typically can be processed at temperatures at the lower end or even slightly below the recommended range; however, highly branched high-density polyethylene (HDPE) must be processed at slightly higher temperatures to preclude breakdown of the polymer chain whereas sparsely branched LLDPE can be processed at the lowest end of the recommended temperature range. On the other hand, some polymers such as acrylonitrile-butadiene-styrene (ABS) with large pendant groups on the polymer backbone must be processed at temperatures in the middle of the recommended range to preclude breakdown of the polymer molecule. The optimal temperature for a given polymer can be determined by compounding the masterbatch at progressively lower melt temperatures until the masterbatch quality deteriorates, compounding efficiency decreases after adjusting other operating parameters as described below, or machine operating limits are reached.

The procedure after setting of temperature differs in detail depending on whether the compounding equipment is starve, flood or force-fed. General procedures for each feed condition are given below; however, for all feed conditions, changes to operating parameters should be done in small increments. After each incremental change, the compounding equipment should be allowed to stabilize before determining output rate, energy demand or product quality.

Starve-fed compounders such as twin-screw extruders and continuous mixers or single-screw extruders operated in a starve-fed mode, have three variables (assuming a fixed temperature), two of which may be independent: (1) screw or rotor speed in RPM, (2) feed rate in pounds per hour, and (3) compounder torque in percent of maximum. Depending upon the established operating procedure for the compounding equipment, the torque may be dependent on feed rate and screw or rotor RPM or it may be set at a fixed percentage of maximum. To maximize the compounder efficiency as compared to the "standard" efficiency as defined by masterbatch without aluminosilicate particles, the screw or rotor RPM is increased or decreased. The feed rate is adjusted, typically from a lower to a higher rate, after each change in screw or rotor RPM to maximize the product output rate. After each operating parameter change, the equipment is allowed to stabilize before determining the efficiency or product quality. If the efficiency increases and product quality is maintained at the new RPM, the screw or rotor RPM is adjusted further in the same direction of increase or decrease. Incremental adjustments in RPM and feed rate are continued until one of four events occur: (1) the efficiency decreases from previous operating parameters,

(2) the product quality decreases as indicated by poor dispersion or distribution of additives, or incomplete devolatilization, (3) unacceptable increase in die head pressure or exceeding the motor torque limit, or (4) the compounding equipment floods excessively with masterbatch compound backing up into a vent or feed throat.

Although the most efficient operating parameters for a starve-fed compounder can vary from one compounding operator to another depending on their preferences or on characteristics of the masterbatch formulation, in many instances the newly established screw or rotor rotational speed is lower and the feed rate is higher for masterbatch with aluminosilicate particles. Although a lower rotational speed would intuitively lead one to anticipate a lower output rate, the output rate is invariably increased. Furthermore, in many instances, the new operating parameters create stress and strain rate environments such that drive motor amperage is significantly decreased and the die head pressure is either the same or less.

Single screw-extruders operated in a flood-fed mode have only one independent operating variable — screw rotational speed (assuming a pre¬ determined processing temperature). Motor torque and output rate are dependent on the screw rotational speed. In general, the output rate increases in a nearly linear relation to screw rotational speed; however, at higher rotational speeds the output increase may be slightly less than that predicted by the increase in screw rotational speed.

In typical flood-fed compounding equipment, the primary option is to gradually increase the screw RPM and determine the output rate. The screw RPM can be increased until one of four events occurs: (1) the torque, voltage or amperage limit of the motor is reached, (2) die head pressure becomes excessive,

(3) the efficiency decreases either due to decreased output or increased energy consumption, or (4) product quality decreases. If variation of screw speed does not provide satisfactory efficiency changes, the other options are to modify the barrel temperature profile or melt temperature and determine efficiency as a function of screw speed. In force-fed compounding equipment, there is an additional variable in that the crammer force or cycle speed can be adjusted from lower to higher rates at a given screw rotational speed. As for flood-fed compounders, the maximum efficiency is achieved when further adjustments are precluded by drive-motor limits, unacceptable die head pressure increase, efficiency decrease, or product quality decrease.

Thus, novel masterbatches and methods of compounding such masterbaches have been disclosed. While embodiments and applications of this invention have been shown and described, it would be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein. The invention, therefore is not to be restricted except in the spirit of the appended claims.

Claims

Claims:

1. A masterbatch comprised of

17-50% by weight of resulting composition of milled aluminosilicate glass; 0-50% by weight of resulting composition of fillers and/or functional additives; polymer.

2. The composition of claim 1 , the milled aluminosilicate glass and filler and/or functional additives being formulated for let down into base polymer at 1- 10% by weight of resulting composition.

3. The composition of claim 1 , the aluminosilicate glass being naturally occurring aluminosilicate glass.

4. The composition of claim 3, the naturally occurring aluminosilicate glass having about 20% or less by weight of crystalline minerals.

5. The composition of claim 1 , the aluminosilicate glass being synthetic aluminosilicate glass.

6. The composition of claim 5, the synthetic aluminosilicate glass being dominantly amorphous structure.

7. The composition of claim 1 , the milled aluminosilicate glass having a particle size range of about 2 to 75 microns as measured by laser diffraction spectrometry.

8. The composition of claim 1 , the functional additives being selected from the group consisting of pigments, reinforcing agents, stabilizers, fire retardants, impact modifiers, plasticizers, nano-composites.

9. The composition of claim 1, the polymer being selected from the group consisting of thermoplastics, thermoplastic elastomers and thermoplastic vulcanizates.

10. The composition of claim 9, the milled aluminosilicate glass and filler and/or functional additives being formulated for let down into base polymer at 1- 10% by weight of resulting composition.

11. A method for creating a masterbatch comprising fusing a polymer in compounding equipment; dispersing and distributing about 17-50% by weight of the resulting compound of aluminosilicate glass into the fused polymer through compounding; dispersing and distributing 0-50% by weight of the resulting compound of fillers and/or functional additives into the fused polymer through compounding; maximizing output efficiency as determined by output weight per kilowatt- hour.

12. The method of claim 11 , maximizing output efficiency being at the lowest temperature range possible at which the compounding efficiency as determined by the output in weight per kilowatt-hour is maximized with full compounding.

13. The method of claim 11 , the polymer being selected from the group consisting of thermoplastics, thermoplastic elastomers and thermoplastic vulcanizates.

14. The method of claim 11 , fusing the polymer being in compounding equipment selected from the group consisting of continuous-output single screw extruders, twin-screw extruders, continuous mixers and combinations thereof.

15. The method of claim 11 , maximizing output including selecting screw or rotor rpm and gradually and incrementally increasing feed rate in starve-fed and force-fed compounding equipment.

16. The method of claim 11 , the aluminosilicate glass being naturally occurring aluminosilicate glass with about 20% or less by weight of crystalline minerals.

17. The method of claim 11 , the aluminosilicate glass being synthetic aluminosilicate glass with a dominantly amorphous structure.

18. The method of claim 11 , the functional additives being selected from the group consisting of pigments, reinforcing agents, stabilizers, fire retardants, impact modifiers, plasticizers, nano-composites.

19. The method of claim 11 further comprising letting down the masterbatch into base polymer at 1-10% by weight of resulting composition, the milled aluminosilicate glass and filler and/or functional additives being formulated for let down into polymer at 1-10% by weight of resulting composition.