US3755168A

US3755168A - Lubricant for extrusion of thermoplastics

Info

Publication number: US3755168A
Application number: US00204709A
Authority: US
Inventors: D Mixon; E Barnes
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1971-12-03
Filing date: 1971-12-03
Publication date: 1973-08-28
Anticipated expiration: 1990-08-28

Abstract

An external lubricant useful in the extrusion of thermoplastic goods which consists essentially of water, a water-soluble polyol of the formula R(OH)n wherein R is a multivalent hydrocarbyl radical having two to five carbon atoms and a valence equal to n, and n is the integer 2 or 3, and at least one detergent selected from the group consisting of (a) a nonionic detergent of the formula

WHEREIN R'' is an alkyl hydrocarbon radical having eight to 20 carbon atoms and m has a value in the range of six to 20 and (b) an anionic detergent of the formula

WHEREIN R'''' is an alkyl hydrocarbon radical having eight to 20 carbon atoms and M is selected from the group consisting of sodium, potassium and ammonium.

Description

United States Patent 1 Mixon et al. Aug 28, 1973 LUBRICANT FOR EXTRUSION OF Primary Examiner-Patrick P. Garvin THERMOPLASTICS Assistant Examiner-Andrew H. Metz [75] lnventors: Donald E. Mixon, Bartlesville, Okla; Attorney-Young and Oulgg Estil N. Barnes, lnkster, MlCh. [57] ABSTRACT [73] Ass'gnee: g g i Company An external lubricant useful in the extrusion of thermoart 0 plastic goods which consists essentially of water, a wa [22] Filed: Dec. 3, 1971 ter-soluble polyol of the formula R(Ol-l),, wherein R is I a multivalent hydrocarbyl radical having two to five [2]] Appl' 204709 carbon atoms and a valence equal to n, and n is the integer 2 or 3, and at least one detergent selected from [52] U.S. Cl 252/33.4, 252/49.3, 252/49.5, the group consisting of (a) a nonionic detergent of the 252/52 R formula [51] Int. Cl C10m 3/34 [58] Field of Search 252/33.4, 49.3, 49,5, '--0 [CHzCH1- ]m'- I wherein R is an alkyl hydrocarbon radical having eight [56] References C'ted to 20 carbon atoms and m has a value in the range of UNITED STATES PATENTS SIX to 20 and (b) an anionic detergent of the formula 3,000,826 9/l96l Gilland 252/49.3 3,024,198 3/1962 Harrington et al. 2s2/49.s x HQ 3,264,242 8/1966 Teot 252/52 R X I 3,304,258 2/l967 White et al. 252/49.3 X 3,387,073 6/1968 Larsen 264/209 x wherein R 15 an alkyl hydrocarbon radical having 3,425,940 2/1969 Norton 252/33.4.x ight'to 20 carbon atoms and M is selected from the 3,495,962 2/1970 Norton et al. 252/29 X group consisting of sodium, potassium and ammonium. 3,649,538 3/l972 Hotten 252/49.5 X

4 Claims, No Drawings LUBRICANT FOR EXTRUSION F THERMOPLASTICS This invention relates to a new and improved fluid for lubricating thermoplastic extrusions.

It is known to pass hot thermoplastic extrudate such as a pipe into a water bath for the purpose of cooling the extrudate and fixing it in the desired shape. It is also known that hot thermoplastic pipe can be fixed in a uniformly round shape by passing it through a sleeve of fixed diameter which sleeve leads directly into the water bath. Thus the hot pipe is rounded to the desired diameter and immediately thereafter fixed upon entering the water bath. The hot thermoplastic, however, tends to stick to the walls of the sleeve as the thermoplastic passes through the sleeve. This causes various imperfections in the surface of the extrudate such as streaks, pits, and holes. In addition, the material of the sleeve tends to corrode due to contact with the hot extrudate.

There is thus presented a requirement for an agent which will lubricate the passage of hot extrudate through a sleeve opening into a water bath. The agent must not be a contaminant for the bath; it must protect the surface of the extrudate from damage by the sleeve; and it must deter corrosion of the sleeve material.

Thus, in accordance with this-invention, there is provided an externally applied lubricant which is highly useful in the extrusion of hot thermoplastic materials. In one extrusion procedure, for example, a thermoplastic material is extruded by any known method to, form a pipe; the pipe, which is hot, is thereafter introduced into a water quench bath by way of a sleeve opening, herein referred to as a sizing ring, having a diameter only just large enough to permit passage of the pipe into the water bath. The sizing ring can be used to reduce the diameter of the extrudate and to thus produce a uniformly round pipe. Since the level of water in the bath is above the sizing ring opening, the pipe fits tightly enough in the sizing ring to form a seal. The lubricant of this invention is therefore poured on the outside external pipe surface which contacts the sizing ring immediately before it passes through the sizing ring to lubricate its passage through the ring. Sufficient lubricant is utilized to effect smooth flow and complete coverage of the extrudate surface. Excess lubricant which drips from the pipe surface can be recovered and reused to lubricate as above described. Any lubricant of this invention which enters the water bath causes no deleterious result to the bath, that is, the lubricant is noncontaminating and there is no foaming. In addition, the lubricant of this invention preserves the surface of the pipe and it is not marred or streaked in any way upon passage through the ring and, further, the tendency of the sizing ring which is metal, usually brass or aluminum, tocorrode in the presence of the hot thermoplastic is reduced considerably if not completely eliminated by use of the lubricant of this invention.

The lubricant of this invention is, broadly, a waterpolyol-detergent mixture wherein the quantity ofdetergent in the mixture is no greater than 6 percent by volume of the volume of the water-polyol combination. More specifically, the polyol and water are combined such that the ratio of polyol added to the water to form the polyol-water combination is in the range of 0.25 to 1.5, and preferably 0.75 to 1.25, parts by volume polyol per one part by volume of water. In one preferred embodiment, the ratio of polyol added to water is one part by volume polyol to one part by volume water. To complete the lubricant of this invention the detergent is added to the polyol-water combination such that the quantity of detergent added is in the ratio range of 0.5 to 6, preferably 1 to 4, and still more preferably 2 to 3, parts by volume detergent per parts by volume of the polyol-water combination. In one preferred embodiment the lubricant of this invention is prepared by combining 1 quart of water, 1 quart of polyol, and 50 millileters of detergent. This is approximately 2.7 parts by volume detergent per 100 parts by volume of the polyol-water combination. Since volume is temperature dependent, it is desirable that the volumes of the constituents be measured at approximately the same temperature wherein the temperature of measurement is less than the boiling point of the lowest boiling point constituent employed.

The water used herein can be from any conventional source of industrial, residential, or commercial potable water. It is desirable that the water not be brackish or otherwise highly salty. Y

wherein R is a multivalent hydrocarbyl radical having 2 to 5 carbon atoms and a valence equal to n, and n is an integer having the value 2 or 3.

Examples of polyols useful herein include glycerol, ethylene glycol, l,2-propane diol, l,3-butane diol, 2,3 butane diol, 2,3-pentane diol, 1,3,5-pentane triol, and l,2, 4-butane triol, wherein glycerol, ethylene glycol, and l,2-propane diol are preferred, with glycerol being the most preferred.

The detergent useful herein is selected generally from water-soluble nonionic and anionic detergents.

The nonionic detergents useful herein are preferably ethylene oxide adducts of alkyl phenols which can be represented by the general formula R -Q-O-wmCm-mm-H wherein R is an alkyl hydrocarbon radical having 8 to 20 carbon atoms and'm has a value in the range of 6 to 20. Of these compounds the most preferred are those wherein R is a nonyl radical (C I-I or an octyl radical a m)- These adducts are well known and readily available commercially. For example, ethylene oxide adducts of nonyl phenols having varying numbers of ethylene oxide units are available commercially under the Triton N series from the Rohm & Haas Company, Philadelphia, Pa., and also under the name lgepal" available from General Aniline Film Corporation, Dyestuff and Chemical Division, and from Antara Chemicals. Also, ethylene oxide adducts of octyl phenols are available commercially under the Triton X series of Rohm & Haas. Also, these compounds are readily made by one skilled in the art with techniques well known in the art and therefore, for the sake of brevity and clarity, these known techniques will not be discussed in detail.

Some specific examples of these adducts include the Igepal detergents, shown in the table below, which are composed of ethylene oxide adducts of nonyl phenols, the differences between these detergents using the average m value for the ethylene oxide unit.

Detergent Average In lgepal CO 530 6 lgepal CO 610 9 lgepal CO 630 9.5

lgepal CO 710 10.5 lgepal CO 730 lgepal CO 850 In one preferred embodiment R, in the above formula is a nonyl radical, and m has an average value of 9.5, e.g., lgepal 630.

The anionic detergents useful herein are preferably those aklyl sulfonates represented by the general formula wherein R is an alkyl hydrocarbon radical having 8-20 carbon atoms and M is selected from sodium, potassium, and ammonium.

Examples of some anionic detergents within the scope of the above formula are ammonium dodecylbenzene sulfonate, sodium octylbenzene sulfonate, potassium octadecylbenzene sulfonate, and sodium eicosylbenzene sulfonate.

In one preferred embodiment R" has 12 carbo atoms and M is ammonium, i.e., ammonium dodecylbenzene sulfonate.

It has been noted that the lubricant of this invention is useful to lubricate the passage of a hot thermoplastic material through a close fitting sleeve. Examples of thermoplastic materials useful with the lubricant of this invention include polyethylene, polypropylene, poly(4-methylpentene-l), polybutane, polyhexene, polystyrene, copolymers of ethylene and propylene, ethylene and butene-l, ethylene and hexene-l, styrene and butadiene, polyacrylates such as polymethylmethacrylate poly(vinylchloride), polyamides, and the like.

The thermoplastic material may contain the additives, fillers, retardants, and the various other agents ordinarily incorporated in such materials prior to extrusion.

The following specific examples are provided to further illustrate this invention but not to limit the scope thereof.

EXAMPLE I A mixture of 1 quart distilled water, 1 quart glycerol and 100 milliliters of a solution of ammonium dodecyl sulfonate in alcohol (70:30 parts by weight, respectively) (Orvus K Liquid, Procter & Gamble) was prepared and placed in the lubricating tank of an extruded/vacuum sizing equipment train.

One inch OD pipe was extruded using an ethylenehexene-l copolymer, density (D 1505-68) 0.950 and melt index (D1238-65T) 0.20 using a conventional screw type extruder operating at 100 rmp, a barrel temperature of 360400 F., 2,200 psi at die head to produce 15 feet pipe/minute.

The extruded pipe was fed into a cooling water bath at 70 F. through a brass vacuum sizing ring, the face of which was lubricated by a free flow of the lubricating mixture prepared above at about 1 ml/second. Good surface wetting of the pipe was observed.

The produced pipe had a smooth exterior surface, free of pits and irregularities. There was no polymer hangup at the face plate of the sizing ring after 2 hours of continuous operation.

EXAMPLE II A mixture of one quart distilled water, one quart glycerol and 50 ml of an ethylene oxide adduct of nonyl phenol (lgepal 630, m 9.5; Rohm & Haas, Philadelphia, Pa), was prepared and used in an extrusion test as in Example 1.

The product was entirely satisfactory as in Example I and no buildup of polymer was observed.

Tests were also made with water and a 50/50 waterglycerol mixture. The pipe surface, after 15 minutes or less of operation with water, became streaked and pitted while polymer buildup became noticeable at the face plate of the sizing ring. The glycerol-water mixture was better but streaks developed in the product because the extrudated pipe surface was not sufficiently wetted by the detergentless mixture of glycerol and water. Polymer buildup was again noted.

The water-detergent mixture could not be used because of excessive foaming.

Reasonable variations and modifications are possible within the scope of this disclosure without departing from the spirit and scope thereof.

Having described my invention, that which is claimed '1. An external lubricant useful in the extrusion of thermoplastic goods which consists essentially of water, a water-soluble polyol of the formula R(OH), wherein R is a multivalent hydrocarbyl radical having 2 to 5 carbon atoms and a valence equal to n, and n is the integer 2 or 3, and at least one detergent selected from the group consisting of (a) a nonionic detergent of the forwherein R is an alkyl hydrocarbon radical having 8 to 20 carbon atoms and m has a value in the range of 6 to 20 and (b) an anionic detergent of the formula 1 wherein R" is an alkyl hydrocarbon radical having 8 to 20 carbon atoms and M is selected from the group consisting of sodium, potassium and ammonium, and wherein the ratio of said polyol to said water is in the range of 0.25 to 1.5 parts by volume polyol per one part by volume water and further wherein the ratio of said detergent to the combination of said polyol and said water is in the range of 0.5 to 6 parts by volume detergent per parts by volume of said polyol-water combination.

2. The lubricant of claim'l wherein said polyol is selected from the group consisting of glycerol, ethylene glycol and 1,2-propane diol.

3. A lubricant composition according to claim 1 wherein said polyol is glycerol and said detergent is a nonionic detergent wherein R' has 9 carbon atoms and m has a value of 9.5

4. A lubricant composition according to claim 1 wherein said polyol is glycerol and said detergent is an anionic detergent wherein R" has 12 carbon atoms and M is ammonium.

III

Claims

2. The lubricant of claim 1 wherein said polyol is selected from the group consisting of glycerol, ethylene glycol and 1,2-propane diol.
3. A lubricant composition according to claim 1 wherein said polyol is glycerol and said detergent is a nonionic detergent wherein R'' has 9 carbon atoms and m has a value of 9.5
4. A lubricant composition according to claim 1 wherein said polyol is glycerol and said detergent is an anionic detergent wherein R'''' has 12 carbon atoms and M is ammonium.