SELF-CLEANING POLYPROPYLENE FABRIC WEAVING LUBRICANT
This invention relates to compositions used to inhibit the in- crease m viscosity of lubricants used m manufacturing proces¬ ses. This invention also relates to lubricants and cleaners used in the manufacture of polyolefin products. This invention parti¬ cularly relates to the use of pyrrolidones as an additive to polyolefin processing hydrophobic lubricants.
Lubricants or finishes are added to polyolefins during manufactu¬ ring processes to decrease the friction between the polyolefin and metal processing equipment. The decrease m the friction pre¬ vents the build-up of heat in the processes. For example, when polyethylene or polypropylene is molded into solid parts or ex¬ truded into either thick or thm films, release agents or "slips" agents are added to the polyolefin to prevent an increase in temperature when the polyolefin comes into contact with tne equipment. This feature of the lubricant is useful for preventing material manufactured from polyolefins from being melted or torn.
Finishes or lubricants are used in various stages of processes that weave, spin or draw polyolefin strands into fabrics. For example, lubricants are added to fabric in processes where the fabric becomes a component of a finished good. Lubricants are also useful in processes where adhesives or coatings are applied to the fabric to aid in the adhesion of the coating or adhesive to the polypropylene. Because the lubricant prevents frictional heat build-up, the melting or tearing of the fabric is avoided.
A specific-example of the use of lubricants to protect faoπcs is m the manufacture of carpets. Polypropylene fiber s woven into fabrics that are used as the backing fabric for carpets. The fibers on the face of the carpet are tufted through a poly- propylene fabric and an adhesive is applied to the back of the polypropylene/tuf ed fiber matrix to hold the fibers m place. High speed metal needles push the carpet fiber through the poly¬ propylene fabric backing material 'causing the nigh 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 m pieces of tuft continually falling off of the carpet; or, if the weave is tight, the filaments will break the tufting needles. The lubricant is normally applied to the polyolefin prior to the weaving processes.
One drawback in the use of lubricants in the above described processes is that excess lubricant causes a film to become depo¬ sited on various surfaces of the manufacturing equipment. For example, during the manufacture of carpets a film coats the surfaces of the loom. Another drawbacK is that the metal surfaces of the looms shave the polyolefin filaments to produce a fine polyolefin dust. This dust generally collects at the same areas of the loom where the lubricant film accumulates. The accumula¬ tion of the dust in the lubricant causes an increase in the vi- scosity of the lubricant and lowers ts efficiency.
After continued use of the lubricant, it becomes saturated with the dust and a paste or gel is formed. The dust, film and paste accumulates m critical areas of the loom and contaminates the final woven fabric Thus, workers must periodically clean the looms. To clean the looms, the workers generally dismantle the loom equipment ana spray-dry it with hot water under n gn pres¬ sure 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 (e.g., 140 Solvent or Naphtha 140) .
These cleaning methods can take up to eight hours for each loom and each loom must be cleaned at least several times a year. Thuε, the current cleaning procedures result in significant loom "down-time" . Further, the use of solvents may create fire and other environmental nazards . Also, the clearing solvents gene¬ rally evaporate into the surrounding atmosphere resulting m a significant waste cf material.
Thus, an object of tne invention is to reduce industrial loom "down-time" . Another object of the invention is to reduce or eli¬ minate the exposure of workers to hazardous organic solvents. Yet another object of the present invention is to decrease the ex- pense related to the waste of the solvents. These and other ob¬ jects of the invention will become apparent from the following discussion.
Provided herein is a solution comprising a water soluble solvent and a hydrophobic lubricant. 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 so¬ luble solvent capable of inhibiting an increase in the viscosity of the lubricant; and (c) a polyolefin processing machine contai¬ ned a polyolefin; wherein the lubricant and the solvent are mixed with the polyolefin in the machine. Further provided is a method
for inhibiting an increase m viscosity in a mixture containing a polyolefin and a processing lubricant comprising: (a) adding a water soluble solvent to a polyolefin contained in a polyolefin processing machine wherein said solvent hinders the increase m viscosity of the hydrophobic lubricant; (b) dding said lubricant to said polyolefin contained in said processing machine.
Thus, the invention provides for a solution, system and a method that inhibits the build-up of undesirable pastes and other poly- olefin particulate matter from accumulating in standard lubricants.
Fig. 1 is a graph depicting the viscosity of an embodiment of the present invention in the presence of polypropylene.
Fig. 2 is a graph depicting the viscosity ci yet another embodi¬ ment cf the present invention in the presence or polypropylene.
Fig. 3 is a graph of the invention depicting tne viscosity of an embodiment of the present invention at 39 °C.
Fig. 4 is a graph of the invention depicting the viscosity of an embodiment of the present invention nereir the polyolefin used is polybutylene.
The lubricant solution and system comprises a hydrophobic lubri¬ cant and a water soluble component. Water may also be used as a component of the solution or system. Other components may also be used to carry out che invention such as organo siloxane or sili- cone compounds - e.g , compounds that increase the lubricating properties of the system. Other additional components that may be used to practice the invention include surface tension reducing agents such as surfactants or wetting agents that are normally soluble in either water soluble solvent (or water) or the hydro- phobic component.
The hydrophobic lubricant is preferably a polyolefin processing lubricant or a polyolefin fiber weaving lubricant. The lubricant can be a naturally occurring vegetable or seed oil such as, but not limited to, soybean o l, peanut oil, sunflower oil, canola oil, corn oil, or olive oil. The hydrophobic lubricant also inc¬ ludes epoxidized peanut or soybean oil or propoxylated oil. Pre¬ ferred hydrophobic lubricants comprise polymers of ethylene oxide or propylene oxide. The most preferred lubricants for carrying out the invention are STANTEX 0332 (ethoxylated vegetable oil ba¬ sed polypropylene fiber weaving lubricant manufactured by the Henkel Corporation) , CF - 0802 oil (a synthetic oil polymer of
ethylene/propylene oxide manufactured by Henkel Corporation) and PM-003-10 (Henkel Corporation) .
The water soluble solvent of the invention includes compounds se- lected form the group of alkyl or alkoxy substituted pyrrolido¬ nes. The preferred alkyl or alkoxy substituted pyrrolidone are selected from the group of compounds comprising 2-pyrrolιdones such as N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N- ethyl-2-pyrrolιdone, N-propyl-2-pyrrolidone, N-hydroxye- thyl-2-pyrrolidone, N-hydroxypropyl-2-pyrrolidone or N-bu- tyl-2 -pyrrolidone.
The water soluble solvent may also comprise an alcohol, a glycol or a propylene glycol. Other water soluble solvents that may be used in the invention include methyl, ethyl or propyl ethers. Re¬ presentative compounds are butoxy ethanol, ethylene glycol mono methyl ether, ethylene glycol mono ethyl ether, ethylene glycol mono propyl ether, di-propylene glycol mono methyl ether, propylene glycol mono methyl ether, propylene glycol mono ethyl ether, propylene glycol mono butyl ether, di-propylene glycol mono ethyl ether, dipropylene glycol mono propyl ether, di-propy¬ lene glycol mono methyl ether, tπpropylene glycol mono methyl ethyl 1-mono propyl and mono butyl ethers.
Optionally, the water soluble solvent may comprise blends 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 are readily determined by routine experimentation such as those performed in the experiments set out below. Howe¬ ver, the water soluble solvent must be present in an amount that inhibits the increase of viscosity of the hydrophobic lubricant. The solvent may also be used to dissolve the hydrophobic lubri - cant.
In one embodiment of the invention, the amount of hydrophobic lu¬ bricant ranges from about 10% to about 99% by weight and the water soluble component 'ranges from about 99% to about 1%. A preferred range comprises about 25% to about 76% of the hydropho¬ bic lubricant and about. 75 to 24% of the water soluble solvent. The most preferred range comprises about 55% to about 65% hydro¬ phobic component and about 35% to about 45% water soluble compo¬ nent.
A preferred embodiment of the invention comprises water. In these embodiments, the' amount, by weight, of the components ranges from about 25% to about 76% hydrophobic lubricant; about 40% to about 5% water; and about 40% to about 5% of the water soluble solvent. The preferred range comprises about 55% to about 65% by weight of the hydrophobic lubricant; about 10% to about 25% by weight water; and about 10% to about 25% by weight 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 tne present invention comprises about 17% of NMP about 17% water; and about 66% of the hydrophobic lu¬ bricant PM-003-10 STANTEX, wherein the total amount of the compo- nents, by weight, is 100%.
The solutions used to carry-out the invention are formed by mi xmg together the hydrophobic lubricant, tne water soluble sol vent and the water in a suitable container. Simple agitation (e.g., a propeller type of mixing blade operating at about 60 to 120 rpm) is adequate. The blending of the components is carried out at room temperature. When an alkyl or alkoxy pyrrolidone is present a sharp increase in temperature of the solution will oc¬ cur.
While not being bound to any theory, it appears that hydrogen bonding occurε between the pyrrolidone compounds and water to create a large exotherm. As a result of this exotherm, a rise m the temperature of the solution can be expected. Depending on the amount of water and pyrrolidone present the temperature rise can range from 5°C to 20°C. Althougn some hydrogen bonding occurs between the glycol or glycol ether constituents and water, no ap¬ preciable exotherm is observed when they are mixed together. The complexing of the hydrophobic lubricant with the water soluble solvent appears to interfere with the affinity of the polyolefin dust to be drawn to the hydrophobic lubricant. Inhibiting the af¬ finity of the dust to be drawn to the nydrophobic lubricant al¬ lows the lubricant to remain a flowing liquid.
The present invention also provides a method for inhibiting the increase in viscosity of lubricants m processes that make products out of polyolefins. Examples of the preferred processes include the molding, extruding and weaving of polyolefins such as polyethylene, polypropylene and polybutylene. The invention pro- vides a self-cleaning lubricant, system and method that allows for the continuous clearing of manufacturing equipment such as looms. For example, the addition of NMP to a hydrophobic lubri-
cant used to clean "gum" or "paste" build-up of polyolefins in processes such as molding, extruding or weaving, provides a self- clearing solution which inhibits the formation of the "gum" or "paste" .
The method can be used in processes where polypropylene is used to construct thin films which are used to make packaging materials such as food containing bags or trash bags. In one method, polyethylene is molded into containers for consumable li- quid 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 (1/8 to one inch thick) to make construction materials such as fabricated holding tanks. These methods allow the lubricant to remain a flowing liquid at higher concentrations of polyolefin particulate by preventing the formation of gels or pastes.
One emxiodiment or tne present invention involves a method wherein strands of polyolefin yarn are passed through a bath containing the lubricant. The lubricant and solvent are coated onto the strands of polyolefin yarn using a rotating "kiss roll" apparatus wherein the lubricant and the water soluble solvent are contained in a pan so tnat the yarn passes through the pan via a rotating apparatus traveling at speeds of hundreds of feet 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 mixture directly to the polyolefin yarn prior to the start of the weaving or spinning processes.
Accordingly, the current invention is an improvement over exi¬ sting yarn processing lubricants and can also be used as a lubri - cant system for the processing of any polyolefin yarn or fiber.
The following examples are illustrative only and are not meant to limit the invention in any manner.
Two hundred (200) grams of STANTEX 0332 (ethoxylated vegetable oil based polypropylene fiber weaving lubricant; manufactured by HENKE,L Corp.) and 200 grams of n-methyl-2-pyrrolιdone (NMP) are added to a 600 nil beaker. The beaker was placed onto a magnetic stirring device and the speed was set at a medium setting. The
two components were mixed for 5 minutes until a clear straw colo¬ red solution appeared. The mixing was performed at 24°C.
One hundred (100) grams of NMP and approximately 2 grams of hard agglomerate residue taken form the metal surface of a poly¬ propylene fabric weaving loom was added to a 250 nil beaker. The agglomerate was the result of the thickening of STANTEX 0332 lu- bricating oil and polypropylene dust present on the woven fibers. The clumps of agglomerate began to fall apart immediately.
One hundred and twenty (120) grams of STANTEX 0332 oil and 40.0 grams of N-methyl-2-pyrrolidone were added to a 250 nil beaker to form a solution wherein the solution was stirred (magnetic stir¬ ring apparatus) at medium speed for about five minutes. Forty (40) grams of water was 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 to24°C.
A large sample of polypropylene dust (representative of the dust which accumulates on a polypropylene fiber) was obtained form a polypropylene fabric weaving mill. The polypropylene dust was ad¬ ded, m 2% increments, to samples of 100% STANTEX 0332 oil and to the blend described above. The test was carried out at about 24 °C. The viscosity of the samples were measured using a Brookfield Viscometer Model DV-II (Spindle ΞC4-34; Chamber 13R; and Speed 6) . The results are Iisted in Table 1 and grapned in Figure 1.
Two hundred (200) grams of STANTEX 0332 (ethoxylated vegetable oil based polypropylene fiber weaving lubricant; manufactured by HENKEL Corp.) and 200 grams of n-methyl-2-pyrrolidone (NMP) are added to a 600 nil beaker. The beaker was placed onto a magnetic stirring device and the speed was set at a medium setting. The two components were mixed for 5 minutes until a clear straw colo¬ red solution appeared. The mixing was performed at 24 °C.
The results snow that after 34 % of the polypropylene dust was added to the 100% STANTEX 0332 o l the mixture became a solid-gel whereas the NMP/water/STANTEX 0332 mixture was still a flowing liquid and did not form a solid gel until after 40% of the poly- propylene dust was added to the mixture.
The same experiment as example 3 was performed except that CF-0802 oil was used in place of the STANTEX 0332. CF - 0802 oil is a synthetic oil polymer of ethylene oxide/propylene oxide ma¬ nufactured by Henkel Corporation. The results are listed in Table 2 and graphed in Figure 2.
One hundred (100) grams of STANTEX 0332 lubricating oil and 40 grams of NMP were added to a 250 nil beaker and stirred (magnetic stirrer at medium speed) . As in examples 2 and 3 above, 40 grams of water were and blend to the STANTEX 0332/NMP blend. However, the samples were maintained at a temperature of 39°C. A straight STANTEX blend was also heated up to 39 °C. Viscosity readings were taken for each sample.
Finely ground h gh molecular weight polyethylene dust was added to the solutions m 2% increments. The results as shown m Figure 3 show that at the point where the straight STANTEX 0332 oil gel¬ led, the mixture was still a flowing liquid.
The procedure was carried out as described in Example 4 except that polybutylene dust was used. Similarly, as shown Figure 4, the mixture was still a flowing liquid at the point where the straight oil gelled.
The invention has been described with reference to various speci fie embodiments However, many variations and modifications may be made while remaining withm the scope of the invention.