CA1073570A

CA1073570A - Packaged articles

Info

Publication number: CA1073570A
Application number: CA 259638
Authority: CA
Inventors: William A. Watts; Theodore A. Evans
Original assignee: Goodyear Tire and Rubber Co
Current assignee: Goodyear Tire and Rubber Co
Priority date: 1975-09-29
Filing date: 1976-08-23
Publication date: 1980-03-11
Also published as: DE2641188A1; JPS5242574A; FR2325573B1; GB1557718A; JPS6144643B2; FR2325573A1

Abstract

INVENTORS: Theodore A Evans and William A Watts INVENTION: PACKAGED ARTICLES
Abstract of the Disclosure A package comprised of an article selected from unvulcanized rubber, compounding ingredients for unvul-canized rubber and compounding ingredients for thermo-plastic polymers wrapped in a protective film composite compatible with said unvulcanized rubber or thermoplastic polymer respectively. Said film composite is comprised of an admixture of (1) an unvulcanized elastomeric block copolymer and (2) a thermoplastic aromatic group-containing resin characterized by being soluble in styrene. The invention is further directed to a method of preparing the package and to compounding high unsaturation rubber and thermoplastic polymers prepared by mixing said package with high unsaturation rubber or thermoplastic rubber respectively.

Description

~(173570 ~his invention relates to a packaging film com-posite and to pac~aged unvulcanized rubber and packaged compounding ingredients for various resins and plastics therewith. The invention further relates to a method of compounding rubber and plastics.
Heretofore~ various wrapping materials have been used for packaging unvulcanized rubber and for packaging compounding ingredients used for rubber and plastics. For example~ films of polyethylene have been used for these purposes.
However, polyethylene films ha~e many times presented serious dispersion incompatibility difficulties in the processing and compounding of rubber and various plastic materials. Defective products and articles prepared there~rom containing inherent weaknesses and inconsistent physical properties have occurred because of discrete polyethylene particle content.
Wrapp~ngs of styrene-butadiene-styrene block copolymers have been suggested for wrapping bales of rubber because of their compatability with various rubbers thereby avoiding the serious disadvantages of polyethylene film.
An example of such a method is found in Canadian Patent 794~200.
However, the solution of one problem has been found to create new disadvantages in the field of pac~aging unvulcanized rubber and compounding ingredients therefor.
Such pac~aging or wrapping films are desirably required to be as thin as reasonably possible yet maintain a substan-tial and sufficient degree of structural integrity and ~073570 dimensional stability under stress. Film rupture is a particular potential where large unvulcanized rubber bales are packaged, stored against similar bales, trans-ported and thrown about. The generally commercially available styrene-butadiene-styrene and styrene-isoprene-styrene block copolymers containing 40 percent or less bound styrene are typically of insufficient mechanical strength. Film rupture due to the actual flow of rubber or plastic during storage can be a problem. Thus, for such thin films~ serious difficulties, such as excessive rupture~
can arise for restraining the cold flow of packaged unvul-canized rubber~ or the redistribution of compounding gredients or for preserving the package integrity under in-transit shock loads.
Therefore, it is an obiect of this invention to provide a suitable packaging ~ilm composed of an unvulcan-ized block copolymer composite ~or packaging unvulcanized rubber and for packaging various compounding ingredients therefor as well as to provide a corresponding method for compounding tha rubber itself.
In accordance with thls invention, it has been discovered that a packaging film composite for packaging~
or wrapping~ unvulcanized rubber and for compounding ingre-dients therefor having a thickness in the range of about 0.5 to about 10~ preferably about 0.75 to about 5.0 mils comprises an admixture of (1) 100 percent by weight of an unvulcanized elastomeric block copolymer having the general configuration A - B - A wherein each A is an indepen-dently selected nonelastomeric monovinyl aromatic 107357~) hydrocarbon polymer block selected from styrene, a-methyl styrene and vinyl toluene having an a~erage molecular weight of about 7,000 to about 25,000 and a glass transition tem-perature above about 25C., the total block A content beîng from about 20 to about 40 percent by weight of the copoly-mer, and B is an elastomeric conjugated diene polymer block selected from 1,3-~utadiene and isoprene having an average molecular weight from about 30,000 to about 100,000 and a glass transition temperature below about 10C., said block copolymer being further characterized by having a melt vis-cosity in the range of about 0.1 to about 10 grams/lO min-utes according to ASTM No. D-1238 and, correspondingly (2) about 20 to about 55 weight percent of at least one thermo-plastic aromatic group-containing resin selected from at least one polymer of styrene~ a-methyl styrene~ styrene/a-methyl styrene, vinyl toluene, vinyl toluene/a-methyl sty-rene, indene resins, alkyl phenolic resins, and petroleum and coal tar resins characterized by having an intrinsic viscosity in toluene at 30C. of about 0.02 to about 0.5.
It is understood that such film composite desir-ably contains various typical antiblocking agents, lubri-cants, fillers, pigments and stabilizers.
The elastomeric block copolymers useful in the practice of this invention for the packaging of rubber or various compounding ingredients can be of either the ra-dial-type or of the linear type. Generally, styrene-butadiene-styrene block copolymer is desired.
In general, the radial-type block copolymers are .- .- .. - - . .... - . ... -. .- . : . . . ..

~073570 prepared by coupling AB block polymers with polyfunctional agents as described in U S Patent 3,281,382.
In general, the linear block copolymer type is prepared by any of the methods commonly used ~or block copolymers of styrene and butadiene; for example (1) by first preparing "living" polystyryl lithium from styrene and an alkyl lithium and adding this to a mixture of styrene-butadiene~ (2) by mixing either lithium metal or a dilithium alkyl (e.g., tetramethylene dilithium), both of which are reported to grow at both ends~ (3) by pre-paring polystyryl lithium and sequentially polymerizing butadiene and then styrene~ or (4) polymerizing butadiene with polystyryl lithium and coupling with coupling agents known to those skilled in this art.
The thermoplastic aromatic resins useful in the practice of this invention ~or packaging rubber or various compounding ingredients are aromatic resins desirably selected from styrene~ a-methylstyrene, a-methylstyrene/
vinyl toluene~ a-methylstyrene/styrene, vinyl toluene, indenes~ modified phenolics and resins ~rom petroleum and coal-derived monomers, characterized by ha~ing an intrinsic viscosity in toluene at 30C. of about 0.02 to about 0.5 In general~ the aromatic resins are prepared by conventional polymeriæation techniques, well known to those skilled in the art.
The film composite itself is prepared by (a) dlssolving the block polymer~ resin, protective agents~
and performance additives in a suitable solvent, (b) casting the resultant cement onto a suitable substrate, (c) drying the film, and (d) removing the film from the substrate. The film composite can also be prepared by using melt processing techniques textrusion and calen dering).
Un~ulcanized rubbercan be advantageously packaged according to this invention. Representative of the various unvulcanized rubbers are natural rubber~ synthetic cis-1~4-polyisoprene, rubbery polymers of 1,3-butadiene, butadiene-styrene emulsion or-solution formed rubbery copolymers and copolymers of butadiene and acrylonitrile. All of these heretofore identified rubbers are of the high unsatu-ration type. Namely, they contain an appreciable amount of carbon-to-carbon double bonds therein. Although this invention is partly directed to the packaging of the high unsaturation-type rubbers~ the low unsaturation type can also be packaged if desired. Representative of such low unsaturation rubbers are butyl rubber, which is typi-cally a copolymer containing a major amount of isobutylene and a minor amount of isoprene~ as well as the various ethylene/propylene copolymers and rubbery terpolymers of ethylene/propylene and a minor amount of conjugated diene.
Various rubber compounding resins and ingredients especially resins such as hydrocarbon resins can be packaged according to this invention and then compounded with the unvulcanized rubber. Representative of the various compounding ingredients are fillers, such as clay~ sili-cates~ calcium carbonate and the like; accelerators~ such as, for example, cadmium diethyldithiocarbamate, tetra-1~73570 methyl thiuram disulfide~ benzothiazyl disulfide and the like; antioxidants, such as the well ~nown substituted phenolic, substituted thio esters and amine type; anti-ozonants, such as aniline derivatives, diamines and thio-ureas; curatives, such as sulfur, sulfur providing com-pounds and peroxides; ultraviolet agents such as substi-tuted benzotriazoles and substituted benzophenones; color pigments, such as iron oxide, titanium dioxides and organic dyes; reinforcing pigments, such as carbon black, zinc oxide and hydrated silicon compounds; and processing aids, such as polyethylenes, silicon dioxide, pumice and stearate.
In order for the film to be useful as a packaging composite for packaging unvulcanized rubber and various compounding ingredients, it is necessary to mix with the composite an anti-block agent to prevent the film from sticking to itself. ~his additive is particularly required where the packaged materials are stacked or "containerized"
together in order to prevent them from sticking to each other and making them virtually impossible to separate without actually destroying portions of the package and material. For this purpose, various well-known anti-block agents can be used~ representative of which are fatty acid amides~ silicones~ soaps~ waxes~ pigments, vegetable lecithins, etc.
The block polymer/resin composite film of the present invention has numerous technical advantages which will be evident from the following discussion.
Polyethylene film (PE) is generally used to overwrap bales of rubber to simplify handling and us~.

~735~70 For most applications, the overwrapped bale is used intact;
thus the bale is charged into a banbury or another suitable mixer and the PE film is dispersed throughout the rubber compound during the mixing cycle. However~ in various applications~ the dispersed PE film has caused defects to occur in the end-product during use and is, therefore~ not a suitable overwrap. Films of this in~ention disperse readily in a rubber compound when mixed using conventional equipment.
Even if complete dispersion is not achieved~ defects in the subject film ars minimized because of the inherent ability to co-cure in the rubber matrix.
In other applications~ PE film can present prob-lems. For the production of high impact polystyrene (HIPS), polybutadiene tBR) or butadiene/styrene rubber (~BR) is added directly to the styrene monomer. The overwrap must be characterized by being soluble in styrene, and~ therefore~
PE film is not considered suitable for this application.
Thus~ HIPS film is used to overwrap SBR or BR for use in the production of HIPS, which presents an entirely dif-ferent problem. If the overwrapped ~BR or BR does not meet rlgid specification limits~ it cannot suitably be used for the manufacture of HIPS or even used for conventional pur-pose~ because the HIPS overwrap does not disperse readily in conventional rubber compounds. However, the composite film of the present invention~ having an additional enhanced structural stability~ is soluble in styrene, dispersable in rubber compounds during conventional mixing cycles~ and has the ability to co-cure in the rubber matrix. Therefore~
the composite of this invention overcomes the previous deficiencies and eliminates a requirement for maintaining an inventory of two (PE and HIPS) packaging films.
Because of the technical advantages cited above, the film composite of this invention can readily be used for the packaging of various compo~nding ingredients for unvulcanized rubber and various plastics where tl) dis-persability, (2) ability to co-cure with rubber, or (3) styrene solubility is a requisite.
Therefore, in further accordance with this inven-tion, a pac~aged unvulcanized rubber~ particularly a high-unsaturation rubber as hereinbefore described and parti-cularly a packaged unvulcanized rubber bale intended for storage, comprises such unvulcanized rubber substantially encompassed with an overwrap of the ~ilm composite of this invention. Indeed, the invention is especially useful for the storage of large unvulcanized rubber bales. The term overwrap relates to the film as applied to the unvulcanized rubber~ especially when in bale form. For bale wrapping, two sheets of film are generally used. One sheet is applied to the top of the rectangular shaped bale and the other to its bottom. The sheets are then wrapped around the sides of the bale and their peripheries heat sealed together.
In additional accordance with this invention, a method of compounding rubber is provided, and the corres-ponding compounded rubber is provided which comprises mixing~ and the resulting admixture including the sulfur cured admi~ture, said method comprising mixlng packaged unvulcanized rubber, particularly hereinbefore described - - . . . . . . .. .
. .

1~73570 high unsaturation rubber, over wrapped with the film composite of this invention and conventional compounding ingredients, particularly such ingredients packaged in the film composite of this invention, optionally followed by : 5 sulfur curing said prepared mixture of rubber, packaging film and packaged compounds.
The practice of this invention is further illus-trated by reference to the following examples which are intended to be representative rather than restrictive of the scope of the invention. Unless otherwise indicated, all parts and percentages are by weight.
EXAMPLE I
A thermoplastic film composition consisting of lO0 parts by weight of an unvulcanized elastomeric styrene-butadiene-styrene bloc~ polymer (SBS) blended with 100 parts by weight thermoplastic a-methyl styrene polymer. In the block copolymer~ said polystyrene block is a thermo-plastic polymer portion having a molecular weight in the ~:
range of about lO~000 to about 15~000 and where said diene 20 polymer portion is a rubbery polybutadiene block having amolecular weight in the range of about 60,000 to about 70~000 and further characterized.by having a melt viscosity of less than 1 gramJ10 minutes according to ASTM No. 1238 and containing about 30 parts by weight polystyrene bloc~
and correspondingly about 70 parts by weight polybutadiene block. Said ~-methyl styrene resin is characterized by having an intrinsic viscosity in toluene at 30C. of about 0.13. A small amount of modifiers, antiblock agents and stabillzers were included in the blend. The composite or .

10735~7V

blend ltself was prepared by dissolving the ingredients in tetrahydrofuran at a temperature of about 50oC. The mix-ture was then cast, dried and removed from the casting surface to yield a 1 mil film.
A test to evaluate block, or the tendency of the film to stick to itself, was run by placing two film samples togèther~ face-to-face, so that a 2-inch by 2-inch~
two-ply specimen was obtained. The specimen was placed between two metal plates in a horizontal position and a 1.6 pound per square inch pressure was placed on top of the upper plate. The assembly was placed in a static hot air oven at about 77C. for about 24 hours. At the end of this time, the film was tested for resistance to bloc~ing by measuring the force in grams to separate the films by pulling them apart at about a 90 angle at a rate of about 20 inches per minute.
Block test results favorably indicated that less than 10 grams of force was required to separate the two plies of film.
In addition~ physical property tests were con-ducted to determine structural integrity of the film, results of which are shown in the following Table 1.

~07357C~

_ .
~ U~
m a) h hh ~1 ~ ~ O ~ O O O O ~ O

~; ~ + ~1 O
U~ h a) C) ~1~ h O ~ O O 1~ 0 1~ 1~ rl . t~ (~ ,-1 1~ ~ O C;~ ~
~ ~ ~I ~ ~ ~ ~ (U C) Z1~; ~t + rl ca .~ -{~
~ .
O
h ~ ~ ~ O O O O O o oo o ~ " -O H
~ ~ ~ ~ :
U~ ~
~ a) O ~_ ~q a~
~: h S:~ :
H 0 0 ~ O O ~ ~ h ~2;;h ~ Q ~ co ~ ~1 .' +

H _~
m ~ 0 ~ :
h ~ ~1 O O O ~ O O 1 ~ U~ o ~ ~ J O C~
~ ~ +

u~ r-l ~rl ~I H ~ Q~ h o rl h ~ o ~ ~1 h _~ ~o ~ ~0 ~ O ~
P ~0 ~. u~ v O ~O ~ O Pt O P~ ~ ~ O E~ bD O
h ~QD--~ 0~ O--~ 0~ rl E~ l H`-- 0 p.~ ~ E~ 1 ~ ~ p ~^~
1 ~ 7 3 57 0 The tensile strength (pounds per square inch) and elongation were determined by ordinary rubber testing techniques. The Elmendorf tear is a measure of the tear resistance of the film in grams force at 90 per mil thickness to cause the tear.
Note that with the thermoplastic resin addition, all of the tensile yield, modulus, and Elmendorf tear strength increased although the elongation decreased.
EXAMPLE II
Wrapped bales were prepared of polybutadiene in the thermoplastic film composition of Example I (100 parts SBS, lOO parts thermoplastic a-methyl styrene resin). The 1~ inch x 28 inch x 7 inch bales were wrapped and the film heat sealed on the edges to form the bale envelope. One bale was stacked on top of another and a pressure of 1.6 pounds per square inch was applied for three weeks. After this perlod, the bales were easily separated without adhesion or sticking tendencies. The film did not present a rupturing problem. From the results of this test~ it became apparent that the thermoplastic film composition had structural integrity during application conditions as well as indicated from the physical property data in Example I.
This test also indlcated that the film composition possessed th~ proper dimensional stability while under stress.
EXAMPLE III
A thermoplastic film composition consisting of lOO parts by weight of the styrene-butadiene-styrene of Example I blended with 75 parts by weight of a-methyl styrene thermoplastic polymer of Example I with attendant ~735'70 additives was melt processed into a 0.75 mil film. ~he film was tested according to the method of Example II with similar results.
EXAMPLE IV
- 5 An experiment was conducted where films of Example I and III were evaluated for dispersability in unvulcanized butadiene/styrene copolymer rubber (SBR). The dispersion evaluation was conducted by mixing one percent - of the fllm with SBR on a heated 6 inch x 12 inch mill.
In this case 3.6 grams of film was added to 360 grams of SBR which had been previously mill massed 30 seconds at a mill roll gap of 0.010 to 0.015 inch and a mill roll tem-perature of about 210F. to 212~F. The sheeted rubber mix was continuously passed through the mill gap until all the film was visibly dispersed into the rubber. This test is rather severe since in actual practice the film wrapping on a bale of rubber is typically only about 0.125 percent of the individual bale weight. Less than 2.0 minutes mill time was required to completely disperse the film in the SBR.
EXAMPLE V
An experiment was then conducted to determine the effect of the films such as those of E~amples I and III on the integrity of cured rubber specimens, particularly where the film is improperly dispersed in the rubber compound. A
typical SBR tire tread stock was sheeted off a mill at 0~050 inch thickness to prepare specimens for evaluation.
A ~ inch x 6 inch template was used to cut two 0.050 inch tread stock samples and one film sample for each laminate ~73570 to be tested. The tread stock/film/tread stock laminate, with a 1~ inch x ~ inch Teflon (TFE), a trademark of the E. I. du Pont de Nemours & Co.~ strip across the width, was cured in a press for about 12 minutes at about 3250F. under pressure. The specimens were removed immediately from the mold and then permitted to cool to ambient temperature or about 250C., for evaluation. Each test specimen was care-fully inspected for voids. Then, an effort was made to separate the tread stock plies at the film/tread stock interface. Films prepared from a block polymer/resin blend of this invention ef~ectively cured in place in the typical SBR tread stock and defied separation at the film/
tread stoc~ interface, which is equivalent to the results obtained with a control laminate of SBR stock without any resin filmO In contradistinction, test specimens similarly prspared of polyethylene film~SBR and of high impact poly-styrene film/SB~ contained numerous voids and separated readily at the film/tread stock interface.
EXAMPLE VI
An experiment was conducted to determine the solubility of the thermoplastic resin film composite of Example I in styrene monomer. The solubility of the film was determined by measurlng the time requ~red to dissolve 5 grams of film in 95 grams of styrene monomer in a 4-ounce bottle at about 250C. The capped bottle was agitated on a wrist action shaker. The experimental film was observed to completely dissolve in 35 minutes. These results are acceptable when compared to the typical speci-fications of butadiene rubber dissolving time of about 1~735~0

2 hours maximum time in styrene. These results also show that the ~ilm could be useful for packaging compounding - ingredients such as colorants for unsaturated polyester resin/styrene monomer compositions.
While certain representative embodiments and details have been shown for the purpose of illustrating the inven-tion~ it will be apparent to those skilled in this art that various changes and modifications may be made therein with-out departing from the spirit or scope of the invention.

Claims

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

1. A packaging film composite having a thickness in the range of about 0.5 to about 10 mils comprised of an admixture of (1) about 80 to about 45 weight percent, based on 100 weight percent, of an unvulcanized elastomeric block copolymer having the general configuration A - B - A wherein each A is an independently selected nonelastomeric monovinyl aromatic hydrocarbon polymer block selected from styrene, .alpha.-methyl-styrene and vinyl toluene having an average molecular weight of about 7,000 to about 25,000 and a glass transition temperature above about 25°C., the total block A content being from about 20 to about 40 percent by weight of the copolymer, and B is an elastomeric conjugated diene polymer block selected from 1,3-butadiene and isoprene having an average molecular weight from about 30,000 to about 100,000 and a glass transition tempera-ture below about 10°C., said block copolymer being further characterized by having a melt viscosity in the range of about 0.1 to about 10 grams/10 minutes according to ASTM No. D-1238, (2) about 20 to about 55 weight percent of a thermoplastic resin selected from at least one polymer of styrene, .alpha.-methylstyrene, styrene/.alpha.-methyl-styrene, vinyl toluene, vinyl toluene/.alpha.-methylstyrene, indene resins, alkyl phenolic resins, petroleum and coal tar resins, said resins characterized by being soluble in styrene and by having an intrinsic viscosity of about 0.02 to about 0.50 as determined in toluene at 30°C. and (3) a sufficient amount of an anti-blocking agent.

2. The packaging film composite of claim 1 having a thickness in the range of 0.5 to 10 mils and characterized by having an anti-block property of less than about 10 grams, comprised of an admixture of an unvulcanized radial or linear styrene-butadiene-styrene elastomeric block copolymer, at least one thermoplastic resin selected from polymers of styrene, .alpha.-methylstyrene and styrene/.alpha.-methylstyrene and optionally containing lubricants, fillers, pigments and stabilizers.

3. In a package of an article wrapped in a film of an unvulcanized block copolymer, the improvement in which said package is comprised of (A) an article selected from at least one of unvulcanized rubber, com-pounding ingredients for unvulcanized rubber, and compounding ingredients for thermoplastic polymers in (B) a packaging film composite of claim 1.

4. The package of claim 3 where said film composite substantially encompasses said article, has a thickness in the range of 0.5 to 10 mils, is charac-terized by having an anti-block property less than about 10 grams, and is comprised of an admixture of an unvul-canized radial or linear styrene-butadiene-styrene elastomeric block copolymer, at least one thermoplastic resin selected from polymers of styrene, .alpha.-methylstyrene or styrene/.alpha.-methylstyrene and optionally containing lubricants, fillers, pigments and stabilizers.

5. The package of claim 3 where said article is an unvulcanized high unsaturation rubber tightly wrapped and optionally heat sealed with said protective film composite comprised of an admixture of said unvul-canized elastomeric block copolymer, thermoplastic resin and optionally containing lubricants, fillers, pigments and stabilizers.

6. The package of claim 5 wherein said article is selected from at least one of butadiene/styrene copoly-mers, polybutadiene and cis-1,4-polyisoprene and where, in said protective film composite, said block copolymer is a radial or linear styrene-butadiene-styrene block copolymer and said thermoplastic resin is selected from at least one polymer of styrene, .alpha.-methylstyrene and styrene/.alpha.-methylstyrene.

7. The package of claim 3 wherein said article is at least one compounding ingredient for unvulcanized rubber.

8. The package of claim 5 where said film composite substantially encompasses said article and is optionally heat sealed and said article is comprised of at least one compounding ingredient for unvulcanized high unsaturation rubber selected from resins, fillers, accelerators, antioxidants, antiozonants, sulfur and peroxide-type curatives and processing aids.

9. The package of claim 8 where said article is selected from at least one of hydrocarbon resins, fillers selected from clay, silicates and calcium carbonate; accelerators selected from cadmium diethyl-dithiocarbamate, tetramethyl thiuram disulfide, benzo-thiazyl disulfide; phenolic, substituted thio ester and amine-type antioxidants; aniline derivative, diamine and thiourea anti-ozonants; sulfur-providing and peroxide curatives; iron oxide and titanium dioxide color pigments;
carbon black, zinc oxide and hydrated silicon compound reinforcing pigments; and polyethylene, silicon dioxide, pumice and stearate processing aids.

10. The package of claim 7, packaged with said film composite, optionally heat sealed, comprised of an unvulcanized elastomeric styrene-butadiene-styrene block copolymer, a thermoplastic resin selected from at least one polymer of styrene, .alpha.-methylstyrene and styrene/
.alpha.-methylstyrene and optionally containing lubricants, fillers, pigments and stabilizers.

11. The package of claim 8 where said article is at least one compounding ingredient for thermoplastic polymers.

12. The package of claim 11 where said article is at least one compounding ingredient for polystyrene.

13. A compounded high unsaturation rubber prepared by mixing a package of claim 11 wherein said article is an unvulcanized high unsaturation rubber with an additional package of claim 11 wherein said article is at least one compounding ingredient for said unvulcanized high unsaturation rubber.

14. A compounded thermoplastic polymer prepared by mixing a thermoplastic polymer with a package of claim 3 wherein said article is at least one compounding ingredient for said thermoplastic polymer.

15. The compounded thermoplastic polymer of claim 14 wherein said thermoplastic polymer is polystyrene.

16. A compounded high unsaturation rubber prepared by mixing an unvulcanized high unsaturation rubber with a package o f claim 7,

17. The compounded high unsaturation rubber of claim 15 where said film composite has a thickness in the range of 0.5 to 10 mils, is characterized by having an antiblock property of less than about 10 grams, and is comprised of said elastomeric block copolymer, thermo-plastic resin and, optionally, containing lubricants, fillers, pigments and stabilizers.

18. The compounded rubber of claim 17, sulfur cured.

19. The compounded rubber of claim 17 where said high unsaturation rubber is selected from at least one of butadiene/styrene copolymers, polybutadiene and cis-1,4-polyisoprene and wherein, in said film composite, said block copolymer is a radial or linear styrene-butadiene-styrene block copolymer and said thermoplastic resin is selected from at least one polymer of styrene, .alpha.-methylstyrene and styrene/.alpha.-methylstyrene.

20. The compounded rubber of claim 17 where said packaged article is comprised of at least one compounding ingredient for unvulcanized high unsaturation rubber selected from resins, fillers, accelerators, anti-oxidants, antiozonants, sulfur and peroxide-type curatives and processing aids.

21. The compounded rubber of claim 20 where said packaged article is selected from at least one of hydrocarbon resins; fillers selected from clay, silicates and calcium carbonate; accelerators selected from cadmium diethyldithiocarbamate, tetramethyl thiuram disulfide and benzothiazyl disulfide, phenolic, substituted thio-ester and amine-type antioxidants; aniline derivative, diamine and thiourea antiozonants; sulfur-providing and peroxide curatives; iron oxide and titanium dioxide color pigments; carbon black, zinc oxide and hydrated silicon compound reinforcing pigments; and polyethylene, silicon dioxide, pumice and stearate processing aids.

22. The compounded rubber of claim 21 which is sulfur cured, where said rubber is selected from at least one of butadiene/styrene copolymers, polybutadiene and cis-1,4-polyisoprene and where, in said film composite, said block copolymer is a styrene-butadiene-styrene block copolymer and said thermoplastic resin is selected from at least one polymer of styrene, .alpha.-methylstyrene and styrene/.alpha.-methylstyrene.

23. In a method of preparing a package of an article wrapped in a film of an unvulcanized block copolymer, the improvement which comprises (A) wrapping an article selected from at least one of unvulcanized rubber, compounding ingredients for unvulcanized rubber, and compounding ingredients for thermoplastic polymers by substantially encompassing with a protective film composite which is compatible therewith said unvulcanized rubber or thermoplastic polymer, said film having a thickness of about 0.5 to about 10 mils and comprised of an admixture of (1) about 80 to about 45 weight percent, based on 100 percent by weight, of an unvulcanized elastomeric block copolymer having the general configura-tion A - B - A wherein each A is an independently selected nonelastomeric monovinyl aromatic hydrocarbon polymer block selected from styrene, .alpha.-methylstyrene and vinyl toluene having an average molecular weight of about 7,000 to about 25,000 and a glass transition temperature above about 25°C., the total block A content being from about 20 to about 40 percent by weight of the copolymer, and B is an elastomeric conjugated diene polymer block selected from 1,3-butadiene and isoprene having an average molecular weight from about 30,000 to about 100,000 and a glass transition temperature below about 10°C., said block copolymer being further characterized by having a melt viscosity in the range of about 0.1 to about 10 gms/10 min according to ASTM No. D-1238, correspondingly (2) about 20 to about 55 weight percent of at least one thermoplastic aromatic group-containing resin selected from at least one polymer of styrene, .alpha.-methylstyrene, styrene/.alpha.-methylstyrene, vinyl toluene, vinyl toluene/
.alpha.-methylstyrene, indene resins, alkyl phenolic resins and petroleum and coal tar resins, said resins characterized by being soluble in styrene and by having an intrinsic viscosity in toluene at 30°C. of about 0.02 to about 0.5 and (3) a sufficient amount of an antiblocking agent and, optionally, (B) heat sealing the film to form the package.