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Monsanto Chemicals
AROCLORS
as Co-Plasticizers for Polyvinylchloride
Monsanto Technical Bulletin No. P-131
May 1, 1948
Monsanto Chemical Company, St. Louis 4 Mo.
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Selected AROCLORS* (chlorinated biphenyls) used as co plasticizers with tricresyl phosphate, dioctyl phthalate and other plasticizers for polyvinylchloride impart good quali ties to the plastics at a substantial reduction in cost. This bulletin describes the practical use of Aroclors with tricresyl phosphate and dioctyl phthalate in polyvinylchlo ride plastics. In each case the saving in cost of the finished plastics is illustrated.
Registered in U.S. Patent Office
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I. INTRODUCTION
Under our present economy the selling price of plasticizers such as tricresyl phosphate, dibutyl phthalate and dioctyl phthalate used for polyvinylchloride plastics are substantially higher than in former years. Aroclors (chlorinated biphenyls), also used as plasticizers for polyvinylchloride, are relatively inexpensive and their use results in substantial savings.
Studies of the properties and economies of Aroclor--tricresyJ phosphate mixtures for polyvinylchloride--have been made particularly in France at the Chemical and Electrometallurgies Products Company's Central Laboratory at Salindres.
The following data indicates the high efficiency of Aroclors mixed with tricresyl phosphate and dioctyl phthalate as plasticizers for polyvinylchloride and the attractive economies offered by using such mixed plasticizers.
II. AROCLOR- TRICRESYL PHOSPHATE MIXTURES COMPARED WITH TRICRESYL PHOSPHATE
PREPARATION OF THE PLASTICS
The plasticizer mixture was composed of equal parts by weight of Aroclor 1254 and tricresyl phosphate. Polyvinylchloride varying in molecular weight from 45,000; 70,000 to 105,000 stabilised with one percent of lead stearate was used.
Conditions for mixing the plastics and working it on the rolls were similar to conditions normally used when tricresyl phosphate or dibutyl phthalate, or mixtures of these plasticizers, are used. The temperature of mixing and rolling the plastics was 14Q-145C, for 45,000 molecular weight polyvinylchloride and 160C. for 70,000 and 105,000 molecular weight mate* rial. Duration of plastic mixing was 5 to 10 minutes and duration of rolling was 18 minutes.
The plastics sheets were molded into test pieces 130x130x3.1 mm. using a pressure of 142 lbs/sq. in. during 13 minutes and then 3,130 lbs/sq. in. during 5 minutes of the molding operation.
COMPARATIVE EVALUATION OF THE PLASTICS
The tensile strength and elongation of the finished plastics are given in the following compara
tive Table 1.
TABLE I.
Tensile
Plasticizer
Molecular
Strength
Elongation
Plasticizer Composition
Percent
Weight
Lbs/sq. in.
Percent
Mixture 50 parts of Aroclor 1254 and 50 parts tricresyl phosphate
105,000 70,000
2,987 2,531
290 300
Tricresyl phosphate
50
105,000
2,278
340
70,000
1,779
300
Mixture 50 parts of Aroclor 1254 and 50 parts tricresyl phosphate
Tricresyl phosphate
45
45,000 70,000
45,000 70,000
2,631 3,130
1,991 2,349
265 28 5
295 305
Mixture 50 parts of Aroclor 1254 and 50 parts tricresyl phosphate
Tricresyl phosphate
35
45,000 70,000
45,000 70,000
3,912 4,057
3,060 3,415
120 180
210 230
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These results show that Aroclor 1254 can be used advantageously as a plasticizer for poly vinylchloride provided that tricresyl phosphate is added to it. This is especially true when the plasticizer mixture is used at a level of at least 45 to 50 percent.
COST COMPARISONS OF THE PLASTICS In computing costs the specific gravity and current selling price for each material as listed were used.
Material
Specific Gravity
Polyvinylchloride.................................. 1.35. Tricresyl phosphate..........................' . 1.17 . Aroclor 1254 .......................................... 1.54 .
Selling Price Per Pound In Carload Quantity
.... $ .33 ...................... 36 ...................... 18
Assuming that the manufacturer desires to make a sheet of the plastics five feet wide, 0.01 feet thick and whatever length can be obtained from 100 pounds of polyvinylchloride, the cost per running foot for each plastics is given in the comparative Table II.
TABLE II.
Plasticizer Comoosition
Tricresyl phosphate Mixture 50 parts Aroclor 1254 and 50 parts tricresyl phosphate
Plasticizer Percent
50
Tricresyl phosphate
Mixture 50 parts Aroclor 1254 and 50 parts tricresyl phosphate
45
Tricresyl phosphate
Mixture 50 parts Aroclor 1254 and 50 parts tricresyl'phosphate
35
Plastics Materials Cost Per Running Ft. for a Sheet 5 Feet
Wide and O'.01 Foot Thick
S 1.350
1.253 $ 0.097 Savings $ 1.355
1.266 $ 0.089 Savings $ 1.360
1.302 s 0.058 Savings
The results indicate that the Aroclor-tricresyl phosphate plasticizer combination offers a saving of 10 cents a running foot when 50 percent plasticization is used, At 45 percent plasti cization the saving is about 9 cents and at 35 percent the saving is about 6 cents a running foot. Use of increased amounts of Aroclor result in greater savings.
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III. AROCLOR-TRICRESYL PHOSPHATE MIXTURES COMPARED WITH DIBUTYL PHTHALATETRICRESYL PHOSPHATE MIXTURES
Frequently, to accomplish better low temperature flexibility and "hand" dibutyl phthalate or dibutyl sebacate plasticizers are added to trieresyl phosphate.
The data given in Table III shows the effectiveness of a dibutyl phthalate-tricresyl phosphate mixture as compared with a mixture of Aroclor 1254-tricresyl phosphate based on tensile strength and elongation characteristics.
TABLE III.
Molecular Weight of the Polyvinyl
chloride
70,000
45,000
Plasti cizer Percent
50 40
50 45 40
45 43 40 35
Mixture of Dibutyl Phthalate
and Trieresyl Phosphate
23 parts - 77 parts
Tensile
Elongation
Strength
Percent
Lbs/sq. in.
370 285
2,205 3.556
Mixture of Aroclor 1254
and Trieresyl Phosphate
50 parts - 50 parts
Tensile
Elongation
Strength
Percent
Lbs/sq. in.
231
2.987
360 335 300
310
250 225
1,650 2,41 9 2.987
1.778
2,349 2.848
300 285 240
265 220 170 120
2,631 3,130 3,558
2,631 2.848 3,272 3,911
Comparison of the underlined values in Table III indicates that provided a greater percentage of the Aroclor-tricresyl phosphate mixture is used, it is possible to obtain tensile strength and elongation qualities similar to those offered by using the dibutyl phthalate-tricresyl phosphate plasticizer combination.
COST COMPARISON OF THE PLASTICS In the cost computations given in Table IV the current selling price for dibutyl phthalate at 35,5 cents a pound in carload quantity was used. The specific gravity value used for this plasticizer was 1.046,
The table compares the cost of the plastics in terms of running feet for a sheet five feet wide and Q.01 foot thick. The cost comparisons are made against the efficiency of the plasticiser mixtures with reference to tensile strength and elongation qualities of the finished plastics as shown in Table III.
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TABLE IV.
Polyvinylchloride
Molecular Weight
Plasticizer Composition
Plasticizer Percent
105.000
23 Parts dibutyl phthalate and 77 parts tricresyl phosphate
50 Parts Aroclor 1254 and 50 parts tricresyl phosphate
40 50
70,000
23 Parts dibutyl phthalate and 77 parts tricresyl phosphate
50 Parts Aroclor 1254 and 50 parts tricresyl phosphate
40 50
45.000
23 Parts dibutyl phthalate and 77 parts tricresyl phosphate
50 Parts Aroclor 1254 and 50 parts tricresyl phosphate
35 43
Plastics Materials Cost Per Running Foot
for a Sheet 5 Feet Wide and 0.01 Foot
Thick
$ 1.339
1.25 2 $ .087 Savings
$ 1.339
1.252 $ . 087 Savings
$ 1.345
1,272 5 .073 Savings
While more Aroclor 1254-tricresyl phosphate mixture was required to give the same plasticication as accomplished with dibutyl phthalate-tricresyl phosphate* the cost figures in Table IV show a decided economy in favor of using the Aroclor plasticizer combination. The economic advantage is about 9 cents a running foot of plastics when the plasticizers are used at a level of about 50 percent. At lower plasticizer concentrations this advantage is about 7 cents a running foot.
IV. AROCLOR-DIOCTYL PHTHALATE MIXTURE COMPARED
WITH DIOCTYL PHTHALATE PLASTICIZER FOR
POLYVINYLCHLORIDE
In the following Table V the composition and comparative physical properties of polyvinyl chloride plasticized with dioctyl phthalate and a 50-50 mixture of Aroclor 1262 and dioctyl phthalate are given. The formulations are typical wire coating compositions. Each contained 100 parts of polyvinylchloride. The amount and type of stabilizer and clay used in each form ula was identical.
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TABLE V.
PROPERTIES OF TYPICAL PVC WIRE COATING COMPOSITIONS
Properties
Dioctyl Phthalate
50-50 Aroclor 1262Dioctyl Phthalate
Parts Plasticizer/100 Resin Plasticiser, Percent Shore A Hardness Tensile Strength, Lbs/sq. in. Elongation, Percent Modulus of Elasticity at 100 Percent Elongation, Lbs/sq. in. Flex. Temp., C. % Water Absorption (24 Hrs.) % Extracted Flammability, sec. Volume Resistivity, 50C.
% Volatile (24 Hr. 105C.)
50 33.3 82 2710 385
1660 -19 .34 .02 75
5.0 x 1013 4.1
80 44.4 79 247 5 375
1475 -15 0.33 0.05 3
8.8 x I0H 6.8
The composition containing Aroclor 1262 plasticiser is far superior to the similar composi tion plasticised with dioctyl phthalate with reference to resistance to burning. Also, the Aro clor composition offers improved insulation resistance. In other respects the properties of the two compositions appear similar.
COST COMPARISON OF THE WIRE COATING COMPOSITIONS The comparative costs of the compositions in terms of a cubic foot of plastics are given in Table VI. The specific gravity value for dioctyl phthalate was taken as 0.980 and the current selling price of 42.5 cents a pound in carload quantities was used.
TABLE VI.
Plasticizer Composition
Percent Plasticizer
Plastics Costs Per Cubic Foot
Dioctyl Phthalate.................
50-50 Aroclor 1262Dioctyl Phthalate ................. ....
44.4................. ..................... 2 5.34 $ 1,70 Savings
The comparative cost figures given in Table VI reflect a saving of $1.70 per cubic foot of plastics or per 100 pounds of polyvinylchloride when the Aroclor-dioctyl phthalate plasticizer mixture is used.
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V. CONCLUSIONS
1. II la definitely indicated to utilise Aroclors (chlorinated biphenyls) as plasticisers for polyvinylchloride provided that trlcresyl phosphate or dioctyl phthalate plasticisers are added to it.
2. In using Aroclor combination plasticisers the total plasticizer content of the plastics mate* rial will be increased. The use of Aroclors offers attractive savings in the costa oi the fin ished plastics materials and results in a substantial saving of trlcresyl phosphate, dibutyl phthalate and dieetyl phthalate.
3. In our present economy, and probably for sometime to come, these ester type plasticizers are both short in supply and substantially more expensive than they were In former years.
4. Aroclors are relatively inexpensive snd the materials are immediately available in large quantity. When used in the suggested combinations with other plasticisers, the Aroclors are efficient snd economical for manufacturing polyvinylchloride plastics materials.
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Monsanto Chemicals
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For further information about Aroclors at co-plastieizors for polyvinylchlorido, contact tho rmarost Monsanto offico
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ST. LOUIS
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