MXPA96005516A - Lubricant for self-cleaning polypropylene fabric - Google Patents

Abstract

The present invention relates to a solution comprising a hydrophobic lubricant, which is selected from a polyolefin pre-treatment lubricant or from a polyolefin fiber tissue lubricant, and a pyrrolidone substituted with alkyl or alco

Description

"LUBRICANT FOR SELF CLEANING POLYPROPYLENE FABRIC" FIELD OF THE INVENTION This invention relates to compositions used to inhibit the increase in viscosity of lubricants used in manufacturing processes. This invention also relates to lubricants and cleaners used in the manufacture of polyolefin products. This invention relates particularly to the use of pyrrolidones as an additive to hydrophobic polyolefin processing lubricants.

BACKGROUND OF THE INVENTION Lubricants or finishes are added to polyolefins during manufacturing processes to decrease friction between the polyolefin and the metal processing equipment. The decrease in friction prevents the accumulation of heat in the processes. For example, when polyethylene or polypropylene is molded into solid pieces or extruded into either thick or thin films, release agents or "slip" agents are added to the polyolefin to prevent an increase in temperature when the polyolefin is placed in contact with the team. This particularity of lubricant is useful to prevent the material made of polyolefins from melting or breaking. Finishes or lubricants are used in various stages of the processes that weave, spin or stretch polyolefin filament into fabrics. For example, lubricants are added to the fabric in processes where the fabric becomes a component of a finished article. Lubricants are also useful in processes where the additives or coatings are applied to the fabric to assist the adhesion of the coating or the adhesive to the polypropylene. Because the lubricant prevents the accumulation of frictional heat, melting or breaking of the fabric is prevented. A specific example of the use of lubricants to protect fabrics is in the manufacture of mats. Polypropylene fiber is woven into fabrics that are used as the background fabric for mats. The fibers on the face of the mat are tufted through a polypropylene fabric and an adhesive is applied upside down from the polypropylene / tufted fiber matrix to hold the fibers in place. The high speed metal needles push the mat fiber through the bottom material of the polypropylene fabric causing the high speed needles to come into contact with the polypropylene filaments. Lubricants must be applied to the fiber or the needles will either break the filaments, which results in the pieces of the plume being continually detached from the mat; or, if the fabric is tight, the filaments will break the needles that effect the tufting. The lubricant is normally applied to the polyolefin before the weaving processes. An inconvenience in the use of lubricants in the processes described above is that the excess lubricant causes a film to deposit on the different surfaces of the manufacturing equipment. For example, during the manufacture of mats, a film covers the surfaces of the loom. Another inconvenience is that the metal surfaces of the looms shave the polyolefin filaments to produce a fine polyolefin powder. This fine powder, in general, is collected in the same areas of the loom where the lubricant film accumulates. The accumulation of fine dust in the lubricant causes an increase in the viscosity of the lubricant and decreases its efficiency. After continuous use of the lubricant, it is saturated with the fine powder and a paste or gel is formed. Fine dust, film and paste accumulate in the critical areas of the loom and contaminate the final woven fabric. Therefore, operators must periodically clean the looms. To clean the looms, the operators usually disassemble the loom equipment and dry it by spraying it with hot water under high pressure to remove the undesirable material. The water may contain a surfactant. An alternative cleaning method is to spray dry the equipment with an organic solvent (v.gr., Solvent 140 or Naphtha 140). These cleaning methods may require up to eight hours for each loom and each loom must be cleaned at least several times a year. Therefore, the current cleaning procedures result in a significant "downtime" of the loom. In addition, the use of solvents can create fire hazards and other environmental hazards. Also, the cleaning solvents, in general, evaporate into the surrounding atmosphere resulting in a significant waste of material. Therefore, an object of the invention is to reduce the "downtime" of the industrial loom. Another object of the invention is to reduce or eliminate the exposure of operators or. hazardous organic solvents. Still another object of the present invention is to decrease the expense related to the waste of the solvents. These and other objects of the invention will become apparent from the following discussion.

COMPENDIUM OF THE INVENTION A solution comprising a water soluble solvent and a hydrophobic lubricant is provided herein. The hydrophobic lubricant further comprises a hydrophobic polyolefin processing lubricant. Also provided herein is a self-cleaning lubricant system comprising: (a) a hydrophobic polyolefin processing lubricant; (b) a water soluble solvent capable of inhibiting an increase in lubricant viscosity and (c) a polyolefin processing machine containing a polyolefin; where the lubricant and the solvent are mixed with the polyolefin in the machine. A method is further provided for inhibiting an increase in viscosity in a polyolefin-containing mixture and a processing lubricant comprising: (a) adding a water-soluble solvent to a polyolefin contained in a polyolefin processing machine, wherein the solvent prevents the increase in the viscosity of the hydrophobic lubricant; (b) add the lubricant to the polyolefin contained in the processing machine. In this way, the invention provides a solution, system and method that inhibits the accumulation of undesirable pulps and other polyolefin particulate matter against accumulation in normal lubricants.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a graph illustrating the viscosity of an embodiment of the present invention in the presence of polypropylene. Figure 2 is a graph illustrating the viscosity of yet another embodiment of the present invention, in the presence of polypropylene. Figure 3 is a graph of the invention illustrating the viscosity of an embodiment of the present invention at 39 ° C. Figure 4 is a graph of the invention illustrating the viscosity of an embodiment of the present invention, wherein the polyolefin used is polybutylene.

DETAILED DESCRIPTION OF THE INVENTION The lubricant solution and system comprises a hydrophobic lubricant and a water soluble component. Water can also be used as a component of the solution or system. Other components may also be used to carry out the invention, such as organosiloxane or silicone compounds - e.g., compounds that increase the lubricating properties of the system. Other additional components that can be used to carry out the invention include surface tension reducing agents such as surface tension agents or wetting agents that are normally soluble either in the water (or water) soluble solvent or the hydrophobic component. The hydrophobic lubricant is preferably a polyolefin processing lubricant or a polyolefin fiber fabric lubricant. The lubricant may be a vegetable or seed oil that occurs naturally, such as but not limited to soybean oil, peanut oil, sunflower oil, canola oil, corn oil or olive oil. The hydrophobic lubricant also includes epoxidized soy bean peanut oil or propoxylated oil. Preferred hydrophobic lubricants comprise polymers of ethylene oxide or propylene oxide. Especially preferred lubricants for carrying out the invention are STANTEX 0332 (ethoxylated vegetable oil based on the polypropylene fiber fabric lubricant manufactured by Henkel Corporation), CF-0802 oil (a synthetic ethylene oxide / propylene oil polymer manufactured by Henkel Corporation) and PM-003-10 (Henkel Corporation). The water soluble solvent of the invention includes compounds that are selected from the group of pyrrolidone substituted with alkyl or alkoxy. Preferred alkyl or alkoxy substituted pyrrolidone is selected from the group of compounds comprising 2-pyrrolidones such as N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2 -pyrrolidone, N-hydroxyethyl-2-pyrrolidone, N-hydroxypropyl-2-pyrrolidone or N-butyl-2-pyrrolidone. The water-soluble solvent may also comprise an alcohol or a glycol or a propylene glycol. Other water-soluble solvents that can be used in the invention include methyl, ethyl or propyl ethers. Representative compounds are butoxy ethanol, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monopropyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, di-propylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monomethyl ether, monomethyl ethyl ethers of tripropylene glycol and monobutyl ether of 1-monopropyl.

Optionally, the water soluble solvent may comprise mixtures of two or more of the water soluble solvents. Similarly, the hydrophobic solvent may also comprise two or more hydrophobic solvents. The amount of the components can vary from application to application and is easily determined by routine experiments such as those carried out in the experiments that will be pointed out below. However, the water-soluble solvent must be present in an amount which inhibits the increase in the viscosity of the hydrophobic lubricant. The solvent can also be used to dissolve the hydrophobic lubricant. In one embodiment of the invention, the amount of the hydrophobic lubricant ranges from about 10 percent to about 99 percent by weight and the water-soluble component ranges from about 99 percent to about 1 percent. A preferred scale comprises from about 25 percent to about 76 percent of the hydrophobic lubricant and from about 75 percent to about 24 percent of the water-soluble solvent. The especially preferred scale comprises from about 55 percent to about 65 percent of the hydrophobic component and from about 35 percent to about 45 percent of the water soluble component. A preferred embodiment of the invention comprises water. In these embodiments, the amount, starting from the components, ranges from about 25 percent to about 76 percent of the hydrophobic lubricant; from about 40 percent to about 5 percent water; and from about 40 percent to about 5 percent of the water soluble solvent. The preferred scale comprises from about 55 percent to about 65 weight percent by weight of the hydrophobic lubricant; from about 10 percent to about 25 weight percent water; and from about 10 percent to about 25 weight percent of the water soluble component. Preferably, the amount by weight of the water-soluble solvent is about the same amount, by weight, as the amount of water present in the invention. A preferred formulation of the present invention comprises about 17 percent NMP; approximately 17 percent water; and about 66 percent of the hydrophobic lubricant PM-003-10 STANTEX, wherein the total amount of the components by weight is 100 percent.

The solutions used to carry out the invention are formed by mixing together the hydrophobic lubricant, the water soluble solvent and the water in an appropriate container. A simple agitation (e.g., a propeller-type mixing blade operating at about 60 to 120 revolutions per minute) is suitable. The mixing of the components is carried out at room temperature. When the alkyl or alkoxy pyrrolidone is present, a pronounced increase in the temperature of the solution will occur. Although it is not desired to be bound by any theory, it seems that hydrogen bonding occurs between pyrrolidone compounds and water to create a large exothermic reaction. As a result of this exothermic reaction, an elevation in the temperature of the solution can be expected. Depending on the amount of water and pyrrolidone present, the elevation in temperature can vary from 5 ° C to 20 ° C. Even though some hydrogen bonding occurs between the constituents of glycol or glycol ether and water, no appreciable exothermic reaction is observed when they are mixed together. The complex formation of the hydrophobic lubricant with the water-soluble solvent appears to interfere with the affinity of the fine powder of the polyolefin to be attracted to the hydrophobic lubricant. By inhibiting the affinity of the fine powder to be attracted to the hydrophobic lubricant, the lubricant is allowed to remain a flowing liquid. The present invention also provides a method for inhibiting the increase in viscosity of the lubricants in the processes that produce the polyolefin products. Examples of preferred processes include molding, extrusion and weaving of polyolefins such as polyethylene, polypropylene and polybutylene. The invention provides a self-cleaning lubricant, a system and a method that allows continuous cleaning of manufacturing equipment, such as looms. For example, the addition of NMP to a hydrophobic lubricant used to clean the accumulation of "gum" or "paste" of polyolefins in processes, such as molding, extrusion or weaving, provides a self-cleaning solution that inhibits the formation of " gum "or" paste ". The method can be used in processes where polypropylene is used to build thin films that are used to produce packing materials, such as bags containing food or garbage bags. In one method, polyethylene is molded into containers for liquid consumable products, such as plastic milk bottles and liquid detergent bottles. The present invention can also be used in applications where polyethylene and polypropylene are extruded into thick films (of a thickness of 3.18 millimeters to 2.54 centimeters) to produce construction materials, such as fabricated holding tanks. These methods allow the lubricant to remain a flowing liquid at higher concentrations of the particulate polyolefin, avoiding the formation of gels or pastes. One embodiment of the present invention involves a method wherein the strands of polyolefin thread are passed through a bath containing lubricant. The lubricant and the solvent are coated on the strands of the polyolefin thread using a rotating "face contact cylinder" apparatus wherein the lubricant and the water soluble solvent are contained in a tray so that the yarn passes through. the tray by means of a rotating apparatus that runs at speeds of hundreds of meters per minute. Although the lubricant and the water-soluble solvent can be added to the polyolefin directly as a mixture or by the addition of one material at a time, the preferred method comprises first mixing the hydrophobic lubricant with the water-soluble solvent and then adding the mix directly to the polyolefin thread before starting the weaving or spinning processes.

Correspondingly, the present invention is an improvement in relation to existing yarn processing lubricants it can also be used as a lubricant system for the processing of any polyolefin yarn or fiber. The following examples are illustrative only and are not intended to limit the invention in any way.

EXAMPLE 1 Two hundred (200) grams of STANTEX 0332 (ethoxylated vegetable oil based on the polypropylene fiber fabric lubricant manufactured by Henkel Corp.) and 200 grams of n-methyl-2-pyrrolidone (NMP) are added to a beaker of 600 milliliter capacity. The beaker was placed in a magnetic stirring device and the speed was graduated to a medium graduation. The two components were mixed for 5 minutes until a solution of crystalline straw color appeared. The mixing was carried out at a temperature of 24 ° C.

EXAMPLE 2 One hundred (100) grams of NMP and about 2 grams of the hard agglomerated residue taken from the metal surface of a polypropylene fabric weave was added to a beaker of 250 milliliter capacity. The agglomerate was the result of the thickening of the lubricating oil STANTEX 0332 and the fine polypropylene powder present in the woven fibers. Agglomerations of the agglomerate began to separate immediately.

EXAMPLE 3 One hundred and twenty (120) grams of the STANTEX 0332 oil and 40.0 grams of N-methyl-2-pyrrolidone were added to a beaker of 250 milliliter capacity to form a solution in which the solution was stirred (magnetic stirring apparatus). medium speed for approximately five minutes. Forty (40) grams of water were added to the solution. The temperature of the solution increased from 24 ° C to 41 ° C. The solution was mixed for another five minutes. The solution was allowed to cool to 24 ° C. A large sample of polypropylene fine powder (representative of the fine powder that accumulates on the polypropylene fiber) of a polypropylene fabric weave mill was obtained. The polypropylene fine powder was added in increments of 2 percent to the 100 percent samples of STANTEX 0332 oil and to the mixture previously described. The test was carried out at a temperature of approximately 24 ° C. The viscosity of the samples was measured using a Brookfield Model DV-II viscometer (Spindle SC4-34, Chamber 13R, and Speed 6). The results are listed in Table 1 and are presented graphically in Figure 1.

TABLE 1 ADDITION OF 2% IN WEIGHT (g) OIL / VISCOSITY pP THE SAMPLE pP (CENTIPOISES) 180 oil / oil mixture 1 1.0175 240 2 1.0459 311 3 1.0274 361 4 1.0024 361 1. 0002 860 1. 0177 1160 1. 0133 1510 8 1.0171 1890 9 1.0026 2390 1.0166 3320 11 1.0142 4090 12 1.0137 5130 13 1.0452 6050 14 1.0331 7050 1.0393 7800 16 1.0136 8850 17 1.0457 10000 18 -. 18 - - 19 - - 20 - BOX 1 (CONTINUED) ADDITION OF 2% IN WEIGHT (g) OIL (MIX) / pP THE SAMPLE pP VISCOSITY (cP) Oil / oil mixture 120 1. 0341 200 1. 0211 270 1. 0133 301 1. 0133 301 1. 0533 501 1. 0188 852 1. 0136 1350 1. 0319 1670 1. 0477 2000 10 1,028 2780 11 1.0183 3190 12 1.0189 3970 13 1.011 4740 14 1.0673 5740 1.0462 6410 16 1.021 7010 17 1.0717 7630 1.0004 8220 19 1.0091 9640 1.0235 10000 The results show that after 34 percent of polypropylene fine powder was added to the 100 percent STANTEX 0332 oil, the mixture became a solid gel, while the NMP / water / STANTEX 0332 mixture was still a liquid and did not form a solid gel until after 40 percent of the polypropylene fine powder had been added to the mixture.

EXAMPLE 4 The same experiment was carried out as in the Example 3, with the exception that CF-0802 oil was used instead of STANTEX 0332 oil. CF-0802 oil is a synthetic oil polymer of ethylene oxide / propylene oxide manufactured by Henkel Corporation. The results are listed in Table 2 and are presented graphically in Figure 2.

TABLE 2 ADDITION OF 2% IN WEIGHT (g) VISCOSITY OF THE OIL (pP) THE SAMPLE pP (cP) Oil / oil mixture - 60.1 1 1.0181 75.2 2 1.0487 95.2 3 1.0227 130 4 1.0184 155 1.0149 204 6 1.0259 326 7 1.0045 429 8 1.0231 589 9 1,001 736 1,004 927 11 1.0155 1190 12 1.0078 1330 13 1.0057 1741 14 1,003 2300 1.0187 2670 16 1.0566 2970 17 1.0633 3390 1. 0655 3770 19 1.0029 4110 1.0342 4780 21 1.0582 5000 22 -. 22 - 23 - 24 - BOX 2 (CONTINUED) ADDITION OF 2% IN WEIGHT (g) (MIXTURE) OF OIL / pP THE SAMPLE pP VISCOSITY (cP) Oil / oil mixture - 30.1 1 1.0734 40.1 2 1.0101 55.1 3 1.0266 75.2 4 1.0183 85.2 1,062 150 6,002 200 7 1.0501 265 8 1,085 388 9 1,051 445 1.0327 596 11 1,084 782 12 1.0885 843 13 1.0017 1040 14 1.0225 1140 1.0248 1280 16 1.0954 1560 17 0.9437 1820 1.0035 2430 19 1.0664 2740 1,0008 3210 21 1.0624 3850 22 1.0035 4430 23 1.017 4930 24 1.0278 5000 EXAMPLE 5 One hundred (100) grams of STANTEX 0332 lubricating oil and 40 grams of NMP were added to a beaker of 250 milliliter capacity and shaken (medium speed magnetic stirrer). As Examples 2 and 3 above, 40 grams of water were added and mixed in the STANTEX 0332 / NMP mixture. However, the samples were kept at a temperature of 39 ° C. A direct STANTEX mixture was also heated to 39 ° C. the viscosity readings were taken for each sample. The finely ground high molecular weight polyethylene fine powder was added to the solutions in increments of 2 percent. These results are shown in Figure 3 and show that at the point where the direct STANTEX 0332 oil gelled, the mixture was still a flowing liquid.

EXAMPLE 6 The procedure was carried out as described in Example 4 with the exception that polybutylene fine powder was used. Similarly, as shown in the Figure 4, the mixture was still a flowing liquid at the point where the oil gelled.

The invention has been described with reference to several specific embodiments. However, many variations and modifications may be made while remaining within the scope of the invention.

Claims (49)

R E I V I N D I C A C I O N E S:

1. A solution comprising a hydrophobic polyolefin processing lubricant and a water soluble solvent.

The solution according to claim 1, wherein the amount by weight of the hydrophobic lubricant ranges from about 10 percent to about 99 percent and the amount by weight of the water-soluble solvent ranges from about 90 percent to about 1 percent.

The solution according to claim 1, wherein the amount by weight of the hydrophobic lubricant ranges from about 25 percent to about 76 percent, and the amount by weight of the soluble solvent varies from about 75 percent to about 24 percent. percent.

The solution according to claim 1, wherein the amount by weight of the hydrophobic lubricant ranges from about 55 percent to about 65 percent, and the amount by weight of the water-soluble solvent ranges from about 35 percent to about 45 percent.

5. The solution according to claim 1, further comprising water.

6. The solution according to claim 2, further comprising water.

7. The solution according to claim 3, further comprising water.

8. The solution according to claim 4, further comprising water.

The solution according to claim 5, wherein the amount by weight of the hydrophobic lubricant ranges from about 25 percent to about 76 percent; the amount by weight of water varies from 40 percent to approximately 5 percent; and the amount by weight of the water-soluble solvent ranges from about 40 percent to about 5 percent.

The solution according to claim 5, wherein the amount by weight of the hydrophobic lubricant ranges from about 55 percent to about 65 percent; the amount by weight of water varies from 10 percent to approximately 25 percent; and the amount by weight of the water-soluble solvent ranges from about 10 percent to about 25 percent.

11. The. solution according to claim 5, wherein the amount by weight of the solvent soluble in water is approximately the same amount by weight of water.

The solution according to claim 1, wherein the water soluble solvent comprises a pyrrolidone substituted with alkyl or alkoxy.

The solution according to claim 2, wherein the water-soluble solvent comprises a pyrrolidone substituted with alkyl or alkoxy.

The solution according to claim 3, wherein the water-soluble solvent comprises a pyrrolidone substituted with alkyl or alkoxy.

15. The solution according to claim 4, wherein the water-soluble solvent comprises a pyrrolidone substituted with alkyl or alkoxy.

16. The solution according to claim 5, wherein the water soluble solvent comprises an alkyl or alkoxy substituted pyrrolidone.

The solution according to claim 6, wherein the water soluble solvent comprises an alkyl or alkoxy substituted pyrrolidone.

18. The solution according to claim 7, wherein the water-soluble solvent comprises a pyrrolidone substituted with alkyl or alkoxy.

19. The solution according to claim 8, wherein the water soluble solvent comprises an alkyl or alkoxy substituted pyrrolidone.

The solution according to claim 9, wherein the water soluble solvent comprises an alkyl or alkoxy substituted pyrrolidone.

The solution according to claim 10, wherein the water soluble solvent comprises an alkyl or alkoxy substituted pyrrolidone.

22. The solution according to claim 11, wherein the water soluble solvent comprises a pyrrolidone substituted with alkyl or alkoxy.

23. The solution according to claim 1, wherein the water soluble solvent comprises N-methyl-2-pyrrolidone.

24. The solution according to claim 2, wherein the water soluble solvent comprises N-methyl-2-pyrrolidone.

25. The solution according to claim 3, wherein the water soluble solvent comprises N-methyl-2-pyrrolidone.

26. The solution according to claim 4, wherein the water soluble solvent comprises N-methyl-2-pyrrolidone.

27. The solution according to claim 5, wherein the water soluble solvent comprises N-methyl-2-pyrrolidone.

28. The solution according to claim 6, wherein the water soluble solvent comprises N-methyl-2-pyrrolidone.

29. The solution according to claim 7, wherein the water soluble solvent comprises N-methyl-2-pyrrolidone.

30. The solution according to claim 8, wherein the water soluble solvent comprises N-methyl-2-pyrrolidone.

31. The solution according to claim 9, wherein the water soluble solvent comprises N-methyl-2-pyrrolidone.

32. The solution according to claim 10, wherein the water soluble solvent comprises N-methyl-2-pyrrolidone.

33. The solution according to claim 11, wherein the water soluble solvent comprises N-methyl-2-pyrrolidone.

34. The solution according to claim 33, wherein the amount by weight of N-methyl-2-pyrrolidone is about 17 percent, the amount by weight of the hydrophobic lubricant is about 66 percent and the amount of water by weight is about 17 percent, where the total amount of the three components by weight is 100 percent.

35. A self-cleaning lubricating system comprising: (a) a hydrophobic polyolefin processing lubricant; (b) a water-soluble solvent capable of inhibiting an increase in the viscosity of the lubricant; and (c) a polyolefin processing machine containing a polyolefin; where the lubricant and the solvent are mixed with the polyolefin in the machine.

36. The system according to claim 35, wherein the machine is a loom.

37. The system according to claim 36, wherein the water soluble solvent comprises an alkyl or alkoxy pyrrolidone.

38. The system according to claim 36, wherein the water soluble solvent comprises N-methyl-2-pyrrolidone.

39. The system according to claim 38, wherein the polyolefin is selected from the group consisting of polyethylene, polypropylene and polybutylene.

40. The system according to claim 38, wherein the polyolefin comprises polypropylene.

41. The system in accordance with the. Claim 39, wherein the polyolefin is polypropylene.

42. The system according to claim 41, wherein the amount by weight of N-methyl-2-pyrrolidone is about 17 percent; the amount by weight of water is approximately 17 percent; and the amount by weight of the lubricant is about 66 percent, wherein the combined weight of the N-methyl-2-pyrrolidone is about 100 percent.

43. A method for inhibiting an increase in the viscosity in the mixture of a polyolefin and a processing lubricant comprising: (a) adding a water-soluble solvent to a polyolefin contained in a polyolefin processing machine, wherein the solvent is capable to inhibit an increase in the viscosity of the polyolefin; and (b) adding the lubricant to the polyolefin contained in the processing machine.

44. The method according to claim 43, wherein the machine is a loom.

45. The method according to claim 44, wherein the water-soluble solvent comprises an alkyl or alkoxy pyrrolidone.

46. The method according to claim 45, wherein the water-soluble solvent comprises N-methyl-2-pyrrolidone.

47. The method according to claim 46, wherein the polyolefin is selected from the group consisting of polyethylene, polypropylene and polybutylene.

48. The system according to claim 46, wherein the polyolefin comprises polypropylene.

49. The system according to claim 47, wherein the polyolefin is polypropylene.