US3548037A - High impact rigid blends of vinyl chloride resins and polymerized tetrahydrofuran - Google Patents

Description

corporated into 99.5 g. of the polyethylene. The results are shown in the following table:

TABLE 6 Surface Static resistance, charge, Antistatic agent ohms volts D-Stat B 1X11) 400 1. 5Xl0 800 5Xl0 500 2X10 200 Plexiklar 5x10 500 1 1 C H CNH(CH -N-OH 1X10 EXAMPLE 7 In another series of comparative tests, there was used a commercial, granulated polypropylene sold under the name Luparen 151 white, this polymer having an intrinsic viscosity of 2.8, a mean molecular weight of 500,000 and a density of 0.905 g./cm.

In each test, 0.1 g. of the antistatic agent as listed in Table 7 were incorporated into 99.9 g. of the polypropylene. The substances were mixed on a conventional rolling mill for five minutes at 175 C. The rolled sheet obtained thereby was cooled to 20 C. and then subjected to a pressure of 180 atm. at 175 C. for two minutes in a press and pressed into sheets 10 cm. square and 2 mm. thick. These sheets were stored for three days at 20 C. in a cabinet maintained at an atmospheric humidity of 46%. The surface resistance and static charge were then determined as in the preceding two examples with the following results:

The same procedure and materials were used as in Example 7 except that 0.5 g. of the antistatic agent were incorporated into 99.5 g. of the polypropylene. The following results were obtained:

TABLE 8 Surface Static resistance, charge, Antistatic agent ohms volts D-Stat B 1X10 400 Ncpcone LV. 2 10 100 Mei-ix Anti-Static 79 0L x10 100 Statikil 12x10 400 Plexiklar 2X10 350 1 I l C H ONH(CHz)3-NOH 5x10 0 It will be readily apparent from these series of comparative tests that antistatic agents commonly used for the surface treatment of various thermoplastic material do no give the same effective results as the particular antistatic agent of the present invention when incorporated or blended into polyethylene or polypropylene as a molding material. Surprisingly, the amine compounds employed herein do give excellent results under these conditions even when used in amounts of less than 1% by weight with reference to the polymonoolefin.

The invention is hereby claimed as follows:

1. A thermoplastic composition comprising a polymonoolefin containing dispersed therein as an antistatic additive about 0.01 to 5% by weight of a compound of the formula in which R denotes a hydrocarbon radical selected from the class consisting of alkyl and alkenyl of 1 to 40 carbon atoms, R and R each denotes lower alkyl of 1 to 4 carbon atoms, R.,, denotes alkylene of 1 to 10 carbon atoms and X denotes a divalent radical selected from the class consisting of -O- and NH-.

2. A composition as claimed in claim 1 wherein said antistatic additive is present in an amount of about 0.1 to 2% by weight with reference to the polymonoolefin.

3. A composition as claimed in claim 1 wherein the polymonoolefin is a polymer selected from the class consisting of polyethylene, polypropylene and mixtures thereof.

4. A composition as claimed in claim 1 wherein the antistatic agent is a compound of the formula in which R denotes a hydrocarbon radical selected from the class consisting of alkyl and .alkenyl of 3 to 20 carbon atoms, R and R each denotes lower alkyl of 1 to 4 carbon atoms, R; denotes alkylene of 2 to 6 carbon atoms and X denotes a divalent radical selected from the class consisting of O-- and NH-.

5. A composition as claimed in claim 1 wherein said antistatic additive is N-lauroyl-N-dimethyltrimethylene diamine.

6. A composition as claimed in claim 5 wherein said polymonoolefin is a polymer selected from the class consisting of polyethylene, polypropylene and mixtures thereof.

7. A composition as claimed in claim 6 wherein said antistatic additive is present in an amount of about 0.1 to 2% by weght with reference to the polymonoolefin.

8. A composition as claimed in claim 6 wherein said polymonoolefin has a molecular weight between 20,000 and 1,000,000, the polyethylene having a density between 0.94 and 0.97 g./cm. and the polypropylene having a density between 0.890 and 0.910 g./cm.

References Cited UNITED STATES PATENTS 2,921,048 1/1960 Bell et al. 26045.9 2,525,691 10/1950 Lee et al. 26031.4 3,190,763 6/1965 Schleepe et al. 106186 2,403,960 7/1946 Stoops et a1. 117-1395 3,211,646 10/1965 Berger 252-s.s

JOSEPH L. SCHOFER, Primary Examiner 5 S. M. LEVIN, Assistant Examiner U.S. Cl. X.R. 26093.7, 94.9

Sample No.parts/wt.

Material A B G D E F PVC batch (above) 84. 75 PTHF (1 =16) 3. 75 7 5 15. PTHF (1 =3.8) 3.75 7.5 15.0 HDT (264 p.S.i.), 69 68 67. 5 69. 5 68 65 Notched Izod it. lbs./in 2. 48 8. 87 2. l9 15. 74 10. 32 8. l5

During the preparation of these blends, samples D through F exhibited quite good processing behavior and formed very smooth molded sheets. Sample C exhibited the poorest processing behavior.

Excess material from sample C above is remilled for various times at various temperatures up to 400 F. At 380 F. the material banded quite well and the smoothness of the bank at the nip of the rolls improved with best milling behavior being obtained at 400 F. The portion milled at 400 F. is press molded as described at 410 F. to form tensile sheets which exhibit an average Notched Izod impact (4 sheets) of 16.48 ft. lbs/in. It appears that the higher molecular weight PTHF requires higher processing temperatures but forms blends of excellent impact resistance. The latter experiment indicates most clearly the great thermal stability of these blends since the total heat history of the sample exhibiting 16.48 ft. lbs/in. Izod impact is quite considerable.

EXAMPLE III In this example, a PTHF made as described in Example I, having an [1;] of 7.57 is employed in blends with the same polyvinyl chloride base resin. In this case the two resins are combined in a container with a fairly large quantity of monomeric THF and rolled on a paint roller until dissolved. The resulting solution is poured into water to precepitate the polymer content and the resulting solid blended material dried overnight in a vacuum oven at 50 C. The dried material in each case is milled to form sheets. The resulting sheets are press molded by the procedure described at 350 F. and the resulting molded sheets subjected to a proprietary dynamic extrusion test employing a constant load rheometer. In this test a quantity of the blend is confined in an orifice-equipped cylinder (orifice d.=0.0459 inch and 1:0.3260 inch) under a piston exerting a constant 400 psi. pressure and the assembly gradually heated While noting and recording the movement of the piston. The temperature at which the piston stops its downward movement (T occurs is the point of full compacting of the plastic and is related to the second order transition temperature. On continued heating beyond the T value, a temperature is reached where the piston again moves downwardly accompanied by extrusion of the plastic through the orifice. The temperature (T at which the latter begins is the melt flow point. The T /T values thus determined together with Instron tensile and elongation values, Shore A Hardness, and tensile impact values (expressed in ft. lbs/in. of thickness) also are listed below.

The above data indicate no pronounced advantage 1n a molecular weight intermediate the 3.8 and 16 values of intrinsic viscosity. However, the data is interesting since the ultimate tensile seems to be high at low PTHF levels, then goes through a minimum in the region of about 25 parts/wt. of PTHF per parts/wt. of PVC and then rise sharply at the 50/50 point of concentration. The extremely high impact values above the PTHF level of about 20 parts/wt. per 100 parts/wt. of PVC indicate a loss of rigidity. Visual examination confirms this since the samples 1 and 2 definitely are more pliable than is sample 4 (l0 PHR level).

The above data indicate that the addition of PTHF depresses both the T and T values of the base resin almost linearly with concentration above the point of 10 parts/wt. of PTHF per 100 parts/wt. of polyvinyl chloride. Compare the relatively small efiect on the HDT values shown in Example II at levels of PTHF below 10 parts/wt. per 100 parts/wt. of the base resin.

The above data, it should be noted, is obtained on formulations containing no added compounding ingredients.

EXAMPLE IV The stability of the blends of this invention is again evaluated by a standard accelerated air oven aging at 350 F. In this example all blends are prepared by milling 5 minutes at 350 F. In this examination several types of control formulations are employed for purposes of comparison. One such type of control is a conventional nonrigid polyvinyl chloride compound plasticized with up to 50 PHR of dioctyl :phthalate compound and the other type is a conventional high-impact rigid polyvinyl chloride employing, as an impact improver, 10 PHR on the polyvinyl chloride of a styrene/acrylonitrile overpolymer on polybutadiene known as Hycar 1010 X 43 made by the B.F. Goodrich Chemical Company, of Akron, Ohio. In the latter experiment, the PVC/1010 X 43 type control blend definitely begins to yellow in the range of from about to about minutes at 350 F. wherein the experimental blend containing 10 PHR of PTHF [1 :33] is not as yellow after as much as 370 minutes as is the PVC/1010 X 43 control at 150 minutes. At the end (920 minutes at 350 F.) of the even aging test, the PVC/ 1010 X 43 control blend is completely black whereas the experimental PTHF blend is only a mustard color or light brown. In the other series of experiments, the blends (prepared by the solution blending technique of Example III) containing various PTHF materials (1 :15.8; 7.6 and 16) containing no stabilizer are compared to unstabilized plasticized (dioctyl phthalate) compounds of the same polyvinyl chloride. Blends containing 10 to 50 PHR or PTHF are slightly better in heat resistance than the controls of corresponding dioctyl phthalate content. While the differences are small, it seems that the samples of blends containing the PTHF of intrinsic viscosity 7.6 are slightly more stable and retained their shape better than the corresponding blends containing PTHF of higher and lower molecular weight.

EXAMPLE V In this example, the preparation of several crosslinked or partially-gelled PTHF materials is described. In each case, about 200 grams of the solid, dry PTHF is dissolved in about 2400 ml. of benzene. To each of the resulting solutions, about 8 grams of dicumyl peroxide and 1.2 grams of sulfur are added and the solution 2 Crystalline-101m.

1 I thoroughly mixed at room temperature to dissolve the peroxide and distribute the additives throughout the mix. The benzene content of each solution is then evaporated off at 50 C. under vacuum. The resulting rubbery material is then placed in a mold under pressure and heated at 150 C. for about 3 hours to induce the cross-linking reaction. Each of the molded materials, each weighing about 210 grams, is placed under Dry Ice to bring about recrystallization (although the same would occur on standing for some time at room temperature). Each molded specimen is tested for gel content by a Soxhlet-type solgel extraction procedure employing 50-mesh wire filter screens and boiling ethyl acetate. The data are as follows:

X-PTHF Parent PTHF 1.11

P.h .r. dicumyl Percent/wt. peroxide Sample No.:

X-PTHF Parent PTHF =3.8

EXAMPLE VI The X-PTHF materials of the foregoing example are combined with polyvinyl chloride (1;:094 by method described above under Vinyl Chloride Resin) each blend containing 10 PHR of X-PTHF. The blends are made using the masterbatch recipe and procedure of Example II and are each prepared by mill-mixing for various in- 12 of 80.8% or 86.6%/wt. gel content are not satisfactory since a mixing time as long as 10-15 minutes at 440 F. is not practical. Secondly, conversion of a very low molecular weight PTHF (7 :11), which per se is too low in molecular weight to produce high impact blends, to a corresponding highly gelled X-PTHF converts the material to an excellent impact improver. The latter material, however, produces blends of lesser thermal stability than the X-PTHF derived from a higher molecular weight PTHF parent. The X-PTHF derived from the PTHF parent of 1 :3.8 exhibits very significantly improved thermal stability, high impact retention and broad processing latitude. The latter blends tenaciously retain their impact strength even after milling for 30 minutes at 335 -380 F. and after as much as 10 minutes at 410440 F. Blends of polyvinyl chloride and the 1010 X 43 type material similar to those of Example IV begin to lose impact strength after 16 or 17 minutes at 380 F. and have essentially completely lost their impact strength in 16 minutes at 410 F. or after 10 minutes at 440 F. The PVC/X-PTHF blends such as those of this example have exceptionally wide processing latitude and great thermal stability. The blends containing X-PTHF are adapted to processing at the highest temperatures and in processing machines exhibiting appreciable hold-up of the stock under the highest processing temperatures.

EXAMPLE VII In this example, the use of auxiliary processing aids is investigated to show whether such are necessary and whether PTHF is compatible with the more common materials used as processing aids and/ or lubricants. In this series of experiments four duplicate blends are prepared each containing 10 PHR of PTHF (1 :3.22) and the Izod impact values reported are obtained by averaging the four values. The data are as follows:

Polyvinyl chloride Lubricant Processing aid base resin T102, Stabihzefl Izod, it./

parts/wt. Type Parts/wt. parts/wt. Type Parts/wt. parts/wt. Parts/wt. lbs/in. Notes 100 Caldium stearate. 2 5 Styrene-acrylonitrile 3 3 10 12. Good bank.

copolymer.

100 do 2 5 Polyethylene 1. 0 3 10 15. 56 D0. 100 do 2 5 Polypropylene z 1.0 3 10 16. 27 Do. 100 Polyethylene 1. 0 5 Same as A 3 3 10 4. 82 Do. 100 Polypropylene 1. O 5 .do 3 3 l0 9. 10 Do. 100 Same as 2 5 None 3 10 1. 61

* Dibutyl tin thioglycollate. I Low molecular weight polyethylene, AC 629 A made by Allied dicated times at various temperatures from 335 to 440 F. The data are as follows:

PVC/X-PTI-IF BLENDS X-PTHF (Parent PTHF, 1 =1.1)

PVC/X-PTHF BLENDS X-PTHF (Parent PTHF, 1 13.8)

Izod vs. time of milling (ft./lbs./in notch) Temp.,

Percent gel C. 5 min. 10 min. 20 min. 30 min.

0 (control) 335 13. 62 13. 41 8. 34 9. 94 Y 380 13. 86 12. 09 13. 05 4. 61

440 6. 01 1. 68 N.d N.d

440 10. 31 12. 66 N.d N.d

440 0. 66 1. N.d N.d

N.d-Not determined.

The above data show several interesting features of the X-PTHF materials as impact-improvers. Firstly, X-PTHF Chemical Corp. 2 Amorphous polypropylene; loW molecular Weight.

It is clear that the good processing behavior of the PVC/PTHF blends of this invention is not due to any particular lubricant or processing aid. Likewise, the good impact resistance of such blends is not due to any particular lubricant/processing aid combination but rather from the PTHF additive. The improvement obtained through such auxiliary is normal.

We claim:

1. A resinous composition comprising for every parts/wt. of a vinyl chloride base resin produced by the polymerization of a monovinylidene monomeric material containing at least 80% wt. of vinyl chloride from about 3 to about 20 parts/wt. of rubbery polymerized tetrahydrofuran exhibiting, in its nongelled condition, an intrinsic viscosity as determined in benzene 25 C. from about 1.5 up to 20 dL/gm.

2. Resinous composition according to claim 1 and further characterized by said base resin is polyvinyl chloride and the said polymerized tetrahydrofuran is uniformly dispersed in the said base resin.

3. A resinous composition according to claim 1 and further characterized by said polymerized tetrahydrofuran possessing a gel content in ethyl acetate of from about 25% to about 80% /wt.

4. A resinous composition according to claim 1 and further characterized by (1) said rubbery polymerized tetrahydrofuran being a substantially gel-free material having an intrinsic viscosity of from about 2 to about 15 and present in a proportion of from about to about parts/wt. and (2) said rubbery polymerized tetrahydrofuran is uniformly dispersed in and thoroughly fiuxed with said base resin.

5. A resinous composition according to claim 1 Wherein the said base resin is polyvinyl chloride, the said polymerized tetrahydrofuran is substantially gel-free material having an intrinsic viscosity as defined of between about 2 and about 4 dl./gm., and is present in a proportion of from about 5 to about parts/wt, and said composition has been blended under high mechanical shear at a temperature of from about 350 to about 440 F.

6. A resinous composition comprising for every 100 parts by weight of a polyvinyl chloride base resin from about 7 to about 15 parts/wt. of a polymerized tetrahydrofuran containing from about to about /wt. of ethyl acetate insoluble gel, said gel-containing polymerized tetrahydrofuran being derived by mixing a low gel polymerized tetrahydrofuran having an intrinsic viscosity as determined in benzene at 25 C. from about 1.0 to about 6.0 dl./ gm. with a peroxide and sulfur and heat- References Cited UNITED STATES PATENTS 3,463,834 8/1969 Dreyfuss 260-899 FOREIGN PATENTS 928,799 6/ 1963 Great Britain.

MURRAY TILLMAN, Primary Examiner C. J. SECCURO, Assistant Examiner US. Cl. X.R.