US3775933A - Method of packaging friable bales of elastomeric material - Google Patents

Abstract

Friable bales of elastomeric crumb formed of porous crumb having a bulk density within the range of 16 to 30 pounds per cubic foot and compressed into bales having a bulk density within the range of 24 to 45 pounds per cubic foot and packaged in separated loadfree compartments for storage or shipment without loss of friability.

Description

United States Patent [1 1 Prescott et al.

[ Dec. 4, 1973 METHOD OF PACKAGING FRIABLE BALES OF ELASTOMERIC MATERIAL [75] Inventors: E. Elsworth Prescott; Edward F.

Copus, both of Baton Rouge, La.

[73] Assignee: Copolymer Rubber & Chemical Corporation, Baton Rouge, La.

[22] Filed: July 9, 1971 [21] Appl. No.: 161,161

[52] US. Cl 53/24, 206/46, 206/65 [51] Int. Cl B651) 63/02 [58] Field of Search 53/24 [56] References Cited UNITED STATES PATENTS 3,461,641 8/1969 Zubik et a1. 53/24 2,779,974 2/1957 Billing et al 53/24 X 3,477,562 11/1969 Allen et al. 53/24 X 3,529,540 9/1970 Ferris .1 53/24 X Primary Examiner-Travis S. McG-ehee Att0rneyMcDougall, Hersh & Scott [57] ABSTRACT Friable bales of elastomeric crumb formed of porous crumb having a bulk density within the range of 16 to 30 pounds per cubic foot and compressed into bales having a bulk density within the range of 24 to 45 pounds per cubic foot and packaged in separated load-free compartments for storage or shipment without loss of friability.

3 Claims, 5 Drawing Figures METHOD OF PACKAGING FRIABLE BALES OF ELASTOMERIC MATERIAL This invention relates to elastomeric materials and more particularly to elastomeric materials packaged in bales for supply by the manufacturer of the elastomeric material to the users thereof. v

In the manufacture of snythetic elastomers, such as SBR rubber, EPDM rubbers, cyclopentadiene rubbers, chloroprene rubbers, butylene rubbers, butadiene homopolyrner and copolymer rubbers and the like, the elastomeric material is produced in the form of crumb which, after drying, is compressed into bales for shipment to compounders for use in the manufacture of elastomeric products, such as belts, tires, matting and the like. The bales are broken down by the compounders for formulating the desired amount of elastomeric material with other rubbers, additives, fillers, curing or vulcanizing agents and the like in the manufacture of elastomeric products.

As in the preparation of EPDM elastomers, as representative of elastomeric materials, the crumb is delivered by the dryer at an elevated temperature and fed to a baler for compaction underpressure to form a bale of the desired density and shape. The bales are delivered, as they are formed, to the packager which encloses the bales in a wrapper of a moisture-proof film of plastic materialand then the bales are stacked in a carton for transfer to storage or shipment.

It has been foundthat the bales of elastomeric crumb are subject to further compaction at the time thatthey are stacked in the carton with the result that the density of the bale, as measured .by specific gravity, continues to rise and the adhesion between the crumb is increased to the extend that theultimate user experiences considerable difficulty in breaking down the bale for removal of the desired amount of elastomeric material in the compounding operation and considerably more work is required to effect the desired uniform distribution of the elastomeric material with the other in,-

gredients duringcompounding.

In addition, .a dense elastomeric crumb is provided which resists admixture for uniform distribution with the other ingredients inzthe compounding operation, with the result that a non-uniform and inferior product is often produced.

Thus, it is an object of this invention to produce and to provide a method for producing a friable bale of vention FIG. Us a perspective view of the rubber crumb, as delivered from the dryer;

FIG. 2 is a schematic view of thebaler for adhering the crumb into a friable bale;

FIG. 3 is aperspective view of the package formed of the bale wrapped in the waterproof plastic;

FIG. 4 is an elevational view of the means in which the bales are stacked in a carton. for storage or.ship ment; and

FIG. 5 is a top plan view of the carton partially filled with bales stacked in accordance with the practice of this invention.

One of the important concepts of this invention re sides in the production of a low density crumb 10 of elastomeric material and the compaction of the crumb to form a friable bale 12 which can be easily broken down into segments for compounding and which is more easily combined with others of the ingredients to produce the compounded rubber or elastomer.

Another of the important concepts of this invention is to provide means for packaging the friable bales of elastomeric material in a manner whereby the friability of the bale can be maintained over extended periods of time in storage or shipment without deterioration of the friability of the bale or the ease by which the elastomeric material can be blended or otherwise mixed with other ingredients to produce a compound in which the materials are more uniformly distributed to yield an improved process and product.

Up .to the point that the elastomeric crumb is .dewatered and dried, the procedure for the production ,of crumb of elastomeric material follows that of conventional practice, such as described in US. Pat. Nos. 3,055,856, 3,079,360 and 3,092,063, and the copending applicationSer. No. 795,664, filed Jan. 31, 1969, now US. Pat. No. 3,593,655, and entitled Meansrfor Extracting Water from Elastomeriic Materials.

Inthe foregoing application, description is made of theme of a modified French oil mill-for the extraction ofwater from the crumb and the issuance of the crumb as dry particles which are then advancedto the baler for compaction to form the bale. The crumb that is produced by the modified French oil mill would normally have a density considerably in excess of 30 to 3.5 pounds per cubic foot and the bale that is produced therefrom would have a densitLin excess of 45 19 50 pound sfper cubic foot before stacking for storage. or

crumb in forming the bale by an amount to increase the bulk density in the bale byabout 50 percent or, in other words, to provide a bale of thelower density crumb in whichthe bale has a bulkdensity withinthe range of 24 to 45 pounds per cubic foot and preferably a bulkdensity of about 34 4 poundsper cubic foot.

EPDM crumb (EPsyn 5508 of Copolymer Rubber & Chemical CorporatiomBaton Rouge, Louisiana) having a bulk density of 22. pounds per cubic foot, representative of a highly porous dry and friable crumb .10, can be produced by processingthe wet crumbthrough a V. D. Anderson dryer wherein the final substantially dried crumb issues from the dryer to produce ahighly porous crumb 10 having a bulkdensity of about 22 pounds per cubic foot and a temperature of about I50-I60 F.

For baling, the temperature of the EPDM crumb should not exceedl F. It is desirable, however, to

allow the crumb to cool to a temperature less than F. and more preferably to a temperature that is proportional to the ethylene content, if it issues from the dryer at a higher temperature.

It is desirable to minimize the amount of dwell of the ram with respect to the compressed bale, otherwise additional undesirable compaction will occur. As a result, the amount of dwell should not be allowed to exceed to seconds and it is desirable to maintain the dwell to as near zero as possible.

Even though the bale has the desired friability from the standpoint of porosity and density when it is removed from the baler 20, if, as a continuous operation, it is packaged by stacking in suitable shipping cartons, in accordance with the conventional practice heretofore employed, the bale will compact further by as much as 50 percent, especially those bales which are at the bottom of the stack and which are subjected to the greatest static load of the bales superposed thereon. Thus much of the original advantage of controlled porosity and density is dissipated whereby many of the original problems return.

The following examples will set forth the conditions for the production of a friable bale of EPDM rubber, but it will be understood that the actual operating conditions can be expanded, as will hereinafter be set forth, for the same or others of the synthetic elastomeric materials, such as of the type heretofore described, which are produced in the form of crumb and baled for packaging for storage or shipment to distant stations.

EXAMPLE 1 The baler was operated at 97 F. Approximately 2.45 cubic feet of low density EPDM crumb 10 having a bound ethylene content of 79 percent was introduced into the cavity 22 having a width of 14 inches and a length of 28 inches. The ram 24 was operated at 500 psi. for 8 seconds to compress the crumb into a space having a height of 7 inches after which the ram was substantially immediately withdrawn to release the pressure with a dwell time of less than one second to produce a bale 26 weighing 54 pounds having the dimensions of 7 X 14 X 28, inches corresponding to a bulk density of about 34 pounds per cubic foot. A

This compares to a weight of 75 pounds for a nonfriable bale of small size produced of crumb of the type heretofore manufactured and provided from the modified French oil mill.

EXAMPLE 2 Similar conditions were used as stated in Example 1 except EPDM crumb having an ethylene content of 83 percent was used. Also, the space height was controlled to 6"/einches and the baler was operated at l 10 F.

EXAMPLE 3 Similar conditions were used as stated in Example 2 and Example 1 except EPDM crumb having an ethylene content of 85 percent was used. The baler was operated at 120 F.

EXAMPLE 4 Packaging Procedure The bale is delivered as a continuous operation from the baler and wrapped for packaging in a heat-scalable moisture-proof film of plastic material.

In accordance with the practice of this invention use is made of a carton 40, such as a carton formed of cardboard or corrugated cardboard dimensioned to have a width corresponding to or slightly greater than a multiple of the width of the bale, a length corresponding to or slightly greater than a multiple of the length of the bale, and a height corresponding to a multiple of the height of the bale.

A partitioning member in the form of an insert 42 of egg crate configuration is inserted into the bottom of a carton to subdivide the lower portion into compartments 44 dimensioned to have a length and width corresponding to and preferably slightly greater than the corresponding dimensions of the bale and a height corresponding to the height of the bale. The insert may be formed with the outer walls of the outermost compartments completely absent since reliance may be had upon the walls 46 of the carton to define the outer walls of the outermost compartments. The freshly formed bales are loaded into the compartments with a separate bale for each compartment.

When all of the compartments in the lower layer have been filled, a cover sheet 48 in the form of a flat panel of cardboard, corrugated cardboard or the like is positioned over the insert whereby the cover sheet is supported substantially throughout its entire area on the upper edges of the insert, as distinguished from resting on the bales. The cover sheet 48 can be formed with downwardly extending flanged edge portions to embrace the underlying insert for greater stability.

When the cover sheet has been placed in position of use, a second insert 50 of the same characteristics as the first is placed on top to define a second layer of compartments which are adapted to be filled with separate bales and this procedure is continued until the desired number of layers is provided to fill the carton with each bale separately confined in each compartment and resting solely on the separating cover sheet between the layers so as to take any load off of the underlying bales.

When the carton has been filled, a cover sheet can be applied over the top layer or use can be merely made of the enclosure 52 to confine the bales within the carton. The enclosure may be in the form of flaps of cardboard which are folded over to enclose the carton or use can be made of a carton cover 52 which telescopes over the top of the carton and is secured thereto by adhesives, tapes or other binding.

It will be understood that the size and weight of the bales may vary within the density range heretofore described and that corresponding variations will follow with respect to the dimensional characteristics of the compartments defined by the various inserts and separators in the carton.

The invention is also applicable in the manner described to rubbers of different compositions which are fabricated in the form of packages formed of compressed crumb particles.

It will be understood that other changes may occur with respect to the construction and composition of the bales of elastomeric material and the carton in which they are packaged without departing from the spirit of the invention, especially as defined in the following claims.

We claim:

1. The method for producing a friable bale of elastomeric material from EPDM crumb comprising the steps of providing a porous elastomeric crumb having a bulk density within the range of 16 to 30 pounds per cubic foot, introducing the crumb into a mold cavity at a temperature below 140F to about 97F, with the temperature proportional to the bound ethylene content of theand enclosing the bale within a wrapper of a waterproof material.

2. The method as claimed in claim 1 in which the compression of the crumb to form the bale is relieved with minimum dwell after the bale has been reduced to the desired density.

3. The method as claimed in claim 1 in which the bale is formed when the density of the crumb is increased by about 50 percent.

* II I!

Claims (3)

1. The method for producing a friable bale of elastomeric material from EPDM crumb comprising the steps of providing a porous elastomeric crumb having a bulk density within the range of 16 to 30 pounds per cubic foot, introducing the crumb into a mold cavity at a temperature below 140*F to about 97*F, with the temperature proportional to the bound ethylene content of the EPDM crumb with the bound ethylene content of the EPDM crumb being above about 79 percent, compressing the crumb by an amount to increase the bulk density to within the range of 24 to 45 pounds per cubic foot to form a bale, removing the bale from the press and enclosing the bale within a wrapper of a waterproof material.

2. The method as claimed in claim 1 in which the compression of the crumb to form the bale is relieved with minimum dwell after the bale has been reduced to the desired density.

3. The method as claimed in claim 1 in which the bale is formed when the density of the crumb is increased by about 50 percent.

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