SE201250C1 - - Google Patents

Description

CLASS INTERNATIONAL SWEDISH C08 f39 b: 22/06 PATENT AND REGISTRATION AGENCY Ans. 12 705/1961 was received on 19/12 1961 issued on 12/4 196 WESTERN ELECTRIC Co. INC., NEW YORK, N.Y. USA Polymericate composition, stabilized against thermal oxidative degradation accelerated by the presence of copper ions and containing a substantially matt polymer of an alkene having at least 3 carbon atoms and a thermal antioxidant Inventor: RH Hansen and CA Russell Priority claimed December 20, 1960 a polymer composition, stabilized against thermal, oxidative degradation accelerated by the presence of copper ions, which contains a substantially matte polymer of an alkene having at least 3 carbon atoms and a thermal antioxidant.

Much attention has recently been paid to the stabilization of polyethylene. It has now been found that various matte free carbonate polymers are better suited for certain applications. Polypropylene in particular is particularly suitable for traditional insulation. This product is tough, hard, sufficient Mpg, resistant to heat dissipation and cracking under pressure, high melting and completely insoluble in many common solvents. But at the same time with these advantages appear aka factors, which prevent the use of these materials especially the susceptibility to thermal oxidation. These higher polymers are easily oxidized due to the relatively high content of tertiary carbon atoms compared to the almost linear materials, such as high density polyethylene. Thermal oxidation of these higher polymers is further catalyzed by metal ions. Due to this tendency to thermal oxidation and the possibility of metal ion catalysis, the oxidative degradation of these higher polymers has been a black problem. In particular, it has been found that the life of polypropylene, although stabilized with the best known antioxidants, in many cases joke allows a technical use in contact with copper. As a primary, electrical insulation, for example for copper wire and copper cables, polypropylene becomes worthless after a few months.

The present invention thus relates to a new, stabilized composition which resists depressive degradation which is induced or accelerated by contact with copper ions. The polymers according to the invention have stone stability both with and without contact with copper.

The Ox marking the invention is that the composition contains an inhibitor compound which contains an oxamide radical.

Polymers according to the invention are those which contain ordered hydrogen atoms. Examples of suitable specific polymers are polypropylene, polybutene-1, poly-3-methylbutene-1, poly-4-methyl-pentene-1, poly-4,4'-dimethylpentene-1, polydodecene-1 and poly-3- methylpentene-1. Mixtures of these polymers and copolymers thereof can be stabilized by the composition of the invention. A mixture falls within the scope of the invention if it is predominantly composed of polymers of the specified character.

The invention also encompasses polymeric compositions which contain minor amounts of additives such as fillers, dyes, inhibitors of ultraviolet degradation such as carbon black and so on. Of particular importance in this context are compounds which can expand the polymers. It has already been stated that expanded polypropylene, if suitably protected against copper poisoning by means of an inhibitor according to the invention, produces an excellent electrical insulating material. Expanded polymers are used for other purposes and concerns due to their lower price. The stabilizing composition according to the invention is fully compatible with known commercial blowing agents and has the effect of limiting their blowing effect.

The new inhibitors against copper ion-catalyzed oxidative degradation are certain compounds, which are usually derived from oxamide, and which have been shown to be mileage radicals by some of these compounds, which have at least this basic structure. have a good inhibitory effect on the above polymers. Examples of such compounds are oxamide, polymers and copolymers of oxamide and derivatives thereof; derivatives of oxamide of the general formula O OH IIIIII • N — C — C — NR van R denote an ethylene or a keto group, and derivatives of oxamide of the general formula O OH IIIIII R1NCCNR2 van in R, and R2 aro cyclic radicals. R 1 and R 2 may be the same or different. They may be homocyclic, heterocyclic, aromatic or polycyclic and may contain 4-6 carbon atoms in each ring.

In the latter cases, R, R, and R, may be arbitrarily substituted.

The following examples show that compounds of the above structure are effective inhibitors when used in accordance with the teachings of this invention. Each example discloses a particular polymeric composition which comprises an inhibitor of the type indicated and in addition a particular electrolyte stabilizer against thermal oxidation. Each example sets forth the results of an accelerated oxidation test to determine the effective life of the polymer in question. In each example, the time in hours is the period of time during which the polymer retains its useful properties. According to this study, it has been found that the effect of the polymer ceases when it has taken up oxygen in a plurality of 10 mug samples. Each stated result is thus a determination of the time at which the specified special composition ceases to act. As can be seen from the examples, the material group tested as inhibitors represents a considerable part of the compounds belonging to the general class of oxamides and their derivatives.

The accelerated aging tests were performed mainly in the following manner: Examples of polymers, which contained additives given in each example, were prepared in a Brabender Plastograph. The brabender was heated to 205-210 ° C. 30 g of resin was introduced into the chamber and heated for 3 minutes in a quake atmosphere. The desired additives were then added in the following amounts: 0.5% antioxidant and inhibitor and 1.4% copper in the form of dust. Dot whole was mixed for 7 minutes.

The copper dust was prepared as follows: Purified electrolyte copper was heated in a reducing bunsen layer to a bright red color, and quickly dipped in a baker with absolute alcohol. The alcohol was decanted, and the copper dust was dried in a vacuum oven for at least 2 hours at 60 ° C. the furnace and the obtained lumps were probed and added to the polymer according to Onskan.

The batch was taken out of the chamber, pressed flat to a thickness of about 0.254 cm, and a portion was pressed in a polished aluminum press for picture frames to a thickness of 0.025 cm. The pressing was completed at a temperature of approximately 175-180 ° C and a pressure of 840-1400 kg / cm 2. The sample is heated at this temperature and at this pressure for 1 minute and the mold is transferred to a cold press for cooling under pressure.

The compressed samples were prepared from a polypropylene composition containing about 10% polyisobutylene and 0.5% 4,4'-thiobis- (3-methyl-6-tert-butylphenol). Granules of the polymer were shaken with 0.5% of the desired inhibitor. The mixture was then extruded in a regular size press. A 0.020-0.025 cm slat plastic insulation (40-50% cavity) was obtained on a 0.911 mm copper wire.

Accelerated thermal oxidation tests, in the amount of oxygen which reacted at atmospheric pressure with a sample in a closed system, were measured volumetrically, challenged at a temperature of 140 ° C. The reaction vessel consisted of Corning No. 4590, oxygen uptake pipettes. An approximately 76.2 cm transparent plastic tube was connected as a level, and a suitable amount of mercury was filled through the plastic tube. the floret was clamped together to limit the flow of mercury, and after inner tubes were introduced which contained the sample and a sufficient amount of Linde 5-A molecular sieve (a zeolite resin) for absorption of CO2 and H 2 O, which were evolved during. the oxidation. The sample consisted of strips of 0.025 cm thick pressed film or lath plastic insulation. including the wire (approximately 0.020-0.025 cm thick with approximately 55% plastic content on 0.911 mm tract).

In these cases, the weight of the dot using the plastic sample was 0.1 g. The pipette was sealed under a constant stream of oxygen after being evacuated and flushed with oxygen several times. The sealed pipette was then placed in a bath of constant, desired temperature and a first volume feed was performed after 15 minutes. The reaction rate was observed by observing the level change of the mercury in the sample pipette compared to a control pipette, which had been prepared at the same time, but without the polymer sample.

It was found that the physical properties (such as brittleness, lack of longitudinal expansion, etc.) of polypropylene formals were markedly degraded after an oxygen uptake of 10 ml per g of polymer. Accordingly, the degree at which the test limit of the test article has been reached is stated as the degree during which the thermal odor has progressed to this degree.

The results of the accelerated aging tests with various compositions, which contained oxamide inhibitors, are shown in the following table. The polymer in Examples 1-16 was polypropylene. Examples 17-20, which refer to poly (butene-1), have been included to demonstrate the applicability of the invention to higher order polymers. In Examples 21-23, the polymer, polypropylene, was expanded by an edge blowing agent, azodicarbonamide, and additionally contained about 10% polyisobutylene. These latter examples show the activity of the stabilizer compositions of the invention in copolymers which contain a predominant portion of polypropylene or higher order polymers.

In each example, columns 2-5 indicate the composition tested according to the above test procedure. The last column indicates the achieved inhibition time yid 140 ° C as explained above. The importance of these time periods as predictable service life in case of unwanted use will be discussed later.

Example Polymerisate Added metal ion Table I. 0.5% thermal antioxidant 1 polypropylene none none 2 4,4'-thiobis- (3-methyl-6-tert-butyl-phenol) 3 Cu 4 6 7 8 9 11 12 13 0 14 0 0 0 16 17 poly (butene71) none none 18 4,4'-thiobis- (3-methyl-6-tert-butyl-phenol) 19 Cu S 21 *) polypropylene 22 *) S 23 *) S 0 , 5% inhibitor none Lifespan in acelated Aging (hours) 1,2 »4 43 oxamide 78 poly- (1,6-diaminehexane) -oxalate poly + 1,4-bis- (aminomethyl) - 141 cyclohexyl-oxalate poly (3 , 3'-diamine-dipropyl-80-amine) -oxalate poly [0.75 1,4-bis- (aminomethyl) -107 cyclohexy] -0.25 1,6-dihexane] oxalate ethylene oxamide oxalylurea N, V-dibenzyl -oxamide N, N'-diphenyl-oxamide N, N'-bis- (o-chloro-phenyl) -oxamide N, N'-bis- (p-tolyl) -oxamide N, N'-bis- (ethoxy- phenyl) -oxamide N, N1-bis- (2-pyridyl) -oxamide ingen »N, N'-diphenyl-oxamide oxamide N, N'-diphenyloxamide ingen 1 60 56 1 76 96 73 9 1,0 3 170 250 82 130 43 * Polymerized expanded with 0.5% azodicarbonamide with 10% polyisobutylene added.

Example 1 (polypropylene) and 17 [poly (butene-1)] show the life of the pure original polymers without the addition of inhibitors. Examples 2 and 18 show the increase in the life of the polymers (on the basis of accelerated aging) after stabilization with 0.5% 4,4'-thiobis- (3-methyl-6-tert-butylphenol), a typical, hand antioxidant. the elongation ratios are expressed have and in other places in the description in weight percent. Examples 3 and 19 indicate the drastic reduction in the life of the most commonly used antioxidant stabilized polymers upon contact with copper. In contrast, Examples 4-16 (polypropylene) and poly (butene-1)] are the increased stabilization of polymers, which already contain an antioxidant (4,4'-thiobis- (3-methyl-6-tert). -butylphenol), by the addition of 0.5% of an inhibitor according to the invention which contains an oxamide radical. It is clear from the time periods given in Table I that polymers which contain the mixture according to the invention have a much more Superior stab resistance to thermal oxidation in the presence of copper than that which can be obtained by using only a commercial antioxidant Examples 21-23 relate to a slat plastic which has been sprayed on the edge with 0.911 mm of copper tride as the primary electrical insulation layer.The thickness of this polymerization insulation was in each case about 0.025 cm 3 and the expansion was achieved by adding 0.5% azodicarbonamide at about 200 ° C. The polymers mentioned in Examples 21-23 also contained 10% poly (isobutylene) to Indian brittleness at low temperatures. These examples have been included to show that the stabilizing mixture according to the invention is useful for mixtures of polymers and jokes have an effect on blowing agents which are used in the polymers. As stated above, the stabilizers according to the invention are of particular interest for use in slat plastic as primary electrical insulation for copper wire, it being necessary for the jaseller expansion agent and the stabilizer to be compatible.

In order to confirm that the stabilizing mixture according to the invention is effective regardless of the choice of antioxidant, a series of examples is given in Table II. Example 24 has been included for control and relates to pure, non-inhibited polypropylene. The test set was the same as in the previous example. The same column headings are used in Table II as in Table I. In each of Examples 25, 28, 31, 34, 37 and 40, another antioxidant was added to the pure polymer, and the efficiency is given in the last column of Table II. In Examples 26, 29, 32, 35, 38 and 41, copper dust was added to the other salt stabilized polymers and the reduction in service life was noted. In Examples 27, 30, 33, 36, 39 and 42, a typical inhibitor of the invention was added and the lifespan was measured.

Table II.

Example Polymerisate Added metal ion 0.5% thermal antioxidant 0.5% inhibitor Lifespan at accelerated Aging (hours) 24 polypropylene none none none none 1,2 2,6-di-tert.-butyl-4-methylphenol 26 Cu 6, 27 N, N'-diphenyloxamide 12 28 none phenyl-fl-naphthylamine none 372 29 Cu 52 N, N'-diphenyloxamide 112 31 none 5-N-pentadecylresorcinol none 164 32 »Cu none 14 33» * N, N'-diphenyloxamide 80 34 »no 6,6'-di-tert.-butyl-106 4,4'-di-o-cresol Cu 14 36 N, N'-diphenyloxamide 100 37 * no 0.5% 4,4'-thiobis- none 423 (3-methyl-6-tert-butylphenol) 0.5% poly-t-1-methyldihydroquinoline 38 Cu 18 39 N, N'-diphenyloxamide 292 none none 77 (6-tert-butyl-3-methylphenol ) 41 Cu 9 42 N, N'-diphenyloxamide 47 201 2 It is clear that in the cases where the known antioxidant materials were added, the service life of the polymer when in contact with copper was significantly increased by the addition of a oxamide compound of the kind previously described. This shows that the oxamide inhibitors according to the invention are effective when used in combination or in combination with known antioxidants.

The added inhibitor retains its activity as long as its amount differs markedly from the range 0.1--5%. If the amount falls below 0.1%, the inhibitor loses its activity. Quantities over 5% have been found to be effective, but no benefit is achieved through the use of stone quantities. Consequently, it is uneconomical to add inhibitors in amounts Over 5%. The amount of antioxidant required depends partly on the degree of activity that different amounts of different antioxidants have and, of course, partly on the desired efficiency. In general, amounts between 0.05% and 5% are recommended for the generally known antioxidant materials.

The significance of the studies with accelerated aging expressed in the effective lifespan during practically radiating conditions phase by extrapolating the time obtained at 140 ° C in hours according to the tables to expected lifespan at the predetermined temperature by an Arrhenius determination at at least 2 other tem .- peraturer. This method of interpreting data from accelerated aging tests is optional in specialized circles and is necessary to be able to prescribe or predict the practical implementation for various desired purposes. The extrapolated values for a typically stabilized polymer according to the invention indicate that an effective stabilization period of 75 hours at 10 G in accelerated aging tests gives an effective stabilization period of 30 Or at 70 ° C.

Claims (8)

Patent claim: A polymeric composition, stabilized against thermal oxidative degradation accelerated by the presence of copper ions, which contains a substantially matt polymer of an alkene having at least 3 carbon atoms and a thermal antioxidant, characterized in that it contains an inhibitor compound containing an oxamide radical. 2. A composition according to claim 1, characterized in that the inhibitor compound consists of oxamide, polymer or copolymer, which contain an oxamide radical, derivatives of oxamides of the general formula HO OH IIIIII N-C-C-N 2 / van in R represents an ethylene or ketone group, or derivatives of oxamides of the general formula HO OH I11I RiNCCNR, wherein RI and R, represent cyclic radicals. 3. A composition according to claim 1, characterized in that the polymer consists essentially of polypropylene. 4. Composition according to claim 1, characterized in that the polymer consists of polypropylene, which contains approximately 10% poly (isobutylene). Composition according to patent claim 1, characterized in that the polymer Or is expanded (slid out of lath plastic). Composition according to Claim 1, characterized in that the polymer consists essentially of poly- (butene-1). A composition according to any one of claims 1-6, characterized in that the inhibitor comprises in an amount of 0.1-5% by weight of the toluene composition. 8. A composition according to claim 1, characterized in that the thermal antioxidant is 4,4'-thiobis- (3-methyl-6-Lert-butylphenol) and is present in an amount of 0.05% by weight of the total composition. . Request publications: Chemical & engineering news. 39 (1961), April 3, pp. 76 and 78 (Oxamides reduce polypropylene oxidation). Representative: H Onn, Stockholm Stockholm 1900. Kungl. Boktr. P. A. Norsteclt & SOner. 660006