US 4,777,211 AGrant
Rubber-Modified Nylon Composition
Issue Date:1988-10-11
•16 Claims
Abstract
A polyamide composition of improved impact resistance comprising a blend of components (A) a graft polymer of a (meth)-acrylate and/or (meth)-acrylonitrile and a vinylaromatic monomer grafted onto a substrate rubber, (B) a polyamide resin, (C) an acid-containing acrylate copolymer rubber and (D) an effective amount of an acid-containing polymer to improve the impact resistance of the polymer blend.
Metadata
Assignee
- Monsanto Company
Inventors
- Richard E. Lavengood
- Raman Patel
- Allen R. Padwa
Application Information
Application Number:US 8810141
Filing Date:1985-07-09
Priority Date:1985-08-21
Art Unit:151
Classifications
IPC:
C08L 7700
Field of Search:
52566;183;179
Patent Drawings
This patent does not have any drawings.
Description
The invention is now described with reference to the following examples which are for the purposes of illustration only and are not intended to imply any limitation on the scope of the invention. The components described below are blended in a number of different ratios and tested for various properties. Parts and percentages are by weight unless indicated otherwise.
ABS-1--prepared by the graft emulsion polymerization of styrene and acrylonitrile in a weight ratio of 70:30 in the presence of polybutadiene-acrylonitrile (93:7) copolymer. ABS-1 contains 40 percent by weight of polybutadiene-acrylonitrile copolymer of which about 4 percent by weight is ungrafted. The weight average molecular weight of the free SAN in the styrene/acrylonitrile graft polymer is in the range from 75,000 to 150,000 as determined by gel permeation chromatography (GPC) using ASTM Method D 3536-76 modified in that four columns in series using micro Styragel.TM. (a trademark of Waters Assoc.) packing are used with a nominal exclusion limit of 5,000 nm, 10,000 nm, 100,000 nm and 1,000,000 nm. The detector is an ultraviolet light detector set at wavelength 254 nm. The test samples are prepared at a concentration of 0.25 weight percent of polymer in tetrahydrofuran. The sample injection size is 0.2 ml and a flow rate of 2 ml/min. at ambient temperature is used.
The grafted polybutadiene has an average particle size in the range of from 0.1 to 0.25 micrometer measured as a weight average particle size diameter with centrifugal photosedimentometer (CPSM) by the published procedure of Graves, M. J. et al "Size Analysis of Subsieve Powders Using a Centrifugal Photosedimentometer", British Chemical Engineering 9:742-744 (1964). A Model 3000 Particle Size Analyzer from Martin Sweets Co., 3131 W. Market St., Louisville, KY is used. The tensile modulus of ABS-1 is about 220,000 psi (1,515.8 MPa).
ABS-2 is prepared by the graft emulsion polymerization of styrene and acrylonitrile in a weight ratio of 80:20 in the presence of polybutadiene-styrene (90:10) copolymer, and contains 35 percent by weight butadiene-styrene copolymer. The grafted copolymer has an average particle size in the range 0.06 to 0.15 micrometer as measured by CPSM as described above. The tensile modulus of ABS-2 is about 1,515.8 MPa.
ABS-3 is a 60:40 mixture of ABS-1 and a grafted composition which is the same as ABS-1 except that the average particle size is in the range of 0.06 to 0.15 micrometer as measured by CPSM. The tensile modulus of ABS-3 is about 1,515.8 MPa.
ABS-4--the same as ABS-1 except that the ungrafted rubber is omitted, and only grafted polybutadiene is present. The tensile modulus of ABS-4 is about 1,515.8 MPa.
Nylon-1--a random copolymer of 85 weight percent nylon 6,6 polymer (poly[hexa-methylene adipamide]) and 15 weight percent nylon 6 polymer (polycaprolactam).
Nylon-2--a nylon 6,6 polymer.
Nylon-3--a random copolymer of 76 weight percent nylon 6,6 polymer and 24 weight percent of nylon 6 polymer.
Nylon-4--a nylon 6 polymer.
Nylon-5--a heat stabilized nylon 6,9 polymer.
Terpolymer-1--a terpolymer prepared by polymerizing a monomer mixture to provide a polymer containing a weight ratio of styrene to acrylonitrile of about 68:32 and a varied amount of maleic anhydride (MA). The weight average molecular weight is in the range from about 60,000 to 100,000 measured by GPC as described above. The tensile modulus of Terpolymer-1 is about 400,000 psi (2,756 MPa).
Terpolymer-2--a terpolymer prepared by polymerizing a monomer mixture of styrene, maleic anhydride and methyl methacrylate to produce a composition in which the above monomers are in the weight ratio of 72:22:6 respectively (22 mole percent maleic anhydride). The tensile modulus of Terpolymer-2 is about 400,000 psi (2,756 MPa).
Copolymer-1 is a copolymer of styrene and maleic anhydride containing 8 weight percent of maleic anhydride, sold by Arco under the trademark Dylark 232.
Rubber-1--a terpolymer of about 73 mole percent of ethylene, about 26 mole percent methyl methacrylate and about 1 mole percent of monoethyl maleate sold as Vamac.TM. G rubber (a trademark of DuPont).
Rubber-2--a thermoplastic copolyetherester elastomer which is a block copolymer of short-chain diol terephthalate and long-chain polyether diol terephthalate available from DuPont Company, Elastomer Chemicals Department, Wilmington, Del. 19898 as Hytrel.TM. 5556 (a trademark of DuPont). This material comprises about 60% by weight of hard segments of polybutylene terephthalate and about 40% by weight of soft segments of polytetramethylene ether terephthalate. Rubber-3--a zinc neutralized ethylene/acrylic acid copoloymer sold as Surlyn.TM. Ionomer 9950 (a trademark of DuPont). Rubber-4--a terpolymer of butyl acrylate/ethyl acrylate/hydroxy ethyl acrylate in a ratio of 79/20/1 weight percent sold as Hycar.TM. 4004 (a trademark of Goodrich).
Rubber-5--an impact modified nylon comprising about 74 weight percent nylon 6,6, about 24 weight percent Rubber-4, and about 2 weight percent maleic anhydride/octadecene copolymer in a weight ratio of 50:50. The amount of rubber added to the blend is back-calculated and is shown as Rubber-5 in the table. The back-calculated nylon portion is added to the amount of Nylon-1 shown in the table.
Rubber-6--an impact modified nylon comprising 80 weight percent nylon 6,6 and 20 weight percent maleated EPDM rubber. The amount of rubber added to the blend is back-calculated and is shown as Rubber-6 in the table. The back-calculated nylon portion is added to the amount of Nylon-1 shown in the table.
Rubber-7--EPDM rubber.
Rubber-8--Maleated EPDM rubber containing about 2 weight percent maleic anhydride functionality.
Rubber-9--a terpolymer of ethylene/alkylacrylate/maleic anhydride sold as Lotader.TM. LX-4110 (a trademark of CdF Chemie).
Rubber-10--a terpolymer of ethylene/alkyl acrylate/maleic anhydride sold as Lotader.TM. HX-8140 (a trademark of CdF Chemie).
Rubber-11--a terpolymer of ethylene/alkyl acrylate/maleic anhydride sold as Lotader.TM. AX-8040 (a trademark of CdF Chemie).
Rubber-12--a mixture of 100 parts Rubber-1 with 23 parts of fumed silica, stabilizers and processing aids sold as Vamac.TM. N-123 (a trademark of DuPont).
In each example and control example, one percent Ethanox.TM. 330 antioxidant, an alkylated phenol available from Ethyl Corporation, is added based on the total weight of the sample. All test specimens are "dry as molded", i.e. the polymers are dried to less than 0.25 weight percent water in the nylon phase and molded and tested.
Izod impact strength is measured according to ASTM D-256-56 with results given in joules/meter (J/m). Unless otherwise indicated the Izod is measured at room temperature on specimens of 0.64 cm width.
Flexural Modulus is measured according to ASTM D-790-66. The sample size is 0.635 cm.times.1.27 cm with a span of 10.16 cm and a 1.27 cm per second cross-head rate. The results are given in megapascals (MPa).
Tensile Yield and Elongation at Fail are measured according to ASTM D-638 with results given in megapascals (MPa) and percent, respectively.
Blows to Fail are measured according to ASTM D-256-56 which has been modified such that the pendulum is dropped at an indicated energy insufficient to break the sample with one blow. The number of blows at that energy required to completely break the samples is the number of blows to fail.
The polymer blends of each example are physically blended by an extrusion process. This involves a preblending step of physically mixing the ABS, terpolymer, rubber and antioxidant and feeding the mixture into a Banbury intensive mixer, Model #69A4782. The rotors are run at about 100 revolutions per minute (RPM) with water cooling. When the stock temperature reaches 199.degree. C., the batch is dumped. The material is sheeted on a two-roll mill, diced, and dried about 16 hours at 60.degree. C. and 98 Newtons/m.sup.2.
The pelletized preblended material of each example is then physically mixed with the nylon and the mixture fed into the Killion extruder possessing a single stage mixing screw (3.8 cm in diameter by 68.6 cm long) which is rotated at about 100 RPM. The rear zone of the extruder is heated to 254.degree. C. with the middle and front zones heated to 260.degree. C. The extruder is connected to a die with a single 0.318 cm diameter orifice through a 0.04 cm to 0.06 cm opening screen pack. The die is heated to 254.degree. C. The extruded material is passed through a water bath and pelletized by a Kissam.TM. pelletizer. The rate of extrusion is 7.26 kgs per hour. The pelletized blended material is then injection molded into specimen bars for testing according to the procedures as set forth above with the testing results concurrently listed for each example in Tables 1 to 9. The injection molding is conducted using a 28.3 g Arburg 200 "S" Allrounder.TM. molding machine available from Arburg Machinenfabrik in Wurttemburg, Germany, possessing a general purpose screw with a check ring and a straight-through nozzle. The molding conditions are as follows:
Example 1 and Controls 1 to 7, shown in Table 1, illustrate the effect of varying the rubber composition on the Izod impact value of the blend. The only blend with an unexpectedly high Izod of 1092 J/m is a blend comprising an acid containing acrylate copolymer (e.g. Example 1).
Examples 2 to 5, shown in Table 2, show the effectiveness of different acid-containing acrylic copolymer rubbers in the blend on Izod. All of the rubbers give polyblends possessing high Izod impact values.
Examples 6 to 10, shown in Table 3, show the effect of different nylon compositions in the blend on Izod, tensile yield and flexural modulus. A wide variety of nylon compositions are shown to be suitable for this blend.
Examples 11 to 13 and Controls 8 and 9, shown in Table 4, show the effect of varying the amount of functionalized rubber in the blend on the toughness of the blend, measured by number of blows to fail. An effective amount of rubber includes the range of 5 to 15 weight percent functionalized rubber in the blend.
Examples 14 to 19 and Controls 10 and 11, shown in Table 5, show the effect on Izod value of increasing the amount of functionalized rubber and decreasing the amount of ABS polymer to maintain a constant rubber level of 20 weight percent in the blend. A high level of impact strength is obtained when the functionalized rubber is in the range of 6 to 15 weight percent of the polyblend.
Examples 20 to 22 of Table 6 show that at constant nylon and compatibilizer content, a high level of impact strength is obtained over a broad concentration range of functionalized rubber.
Examples 23 to 26, shown in Table 7, show the effect of varying the ABS composition in the blend on Izod value of the blend. Control 12 (ABS-2) shows that when the acrylonitrile content of the graft copolymer fraction of the ABS polymer is less than about 25 weight percent, improved impact strength is not observed.
Examples 27 to 35 and Control 13, shown in Table 8, illustrate the effect of varying the amount of terpolymer in the blends on Izod value of the blends. A wide range of terpolymer amounts (0.5 to 10.0 weight percent) corresponding to 0.00006 to 0.0011 mole maleic anhydride per 100 parts by weight of polyblend is effective to enhance impact strength.
Examples 33 to 37 and Control 14, shown in Table 9, show the effect of the amount of maleic anhydride in the terpolymer on the Izod value of the blends. A wide range (0.18 to 4.5 mole percent maleic anhydride) corresponding to 0.00006 to 0.0017 mole maleic anhydride per 100 parts by weight of polyblend is shown to be effective in the blend to enhance impact strength.
Examples 38 to 42 and Controls 15 and 16, shown in Table 10, also show the effect of varying the amount of MA in the terpolymer and varying the amount of terpolymer in the blend. Terpolymers containing 22 mole percent MA are effective in low concentrations (less than 3.0 weight percent) in the blend providing concentrations of maleic anhydride in the range of 0.0002 to 0.003 mole per 100 parts by weight of polyblend (Examples 42-45). Similar results would be observed in blends containing a 50/50 weight percent copolymer of styrene/maleic anhydride.
Examples 46 to 49 and Controls 17 to 19 show that when the weight percent of polar monomer (acrylonitrile) and acid functional monomer (maleic anhydride) of component (D) is less than about 15, the impact strength of the polyblend is less responsive to improvement by addition of component (D).
Claims
We claim:
1. A polymer blend comprising: (A) a graft rubber composition comprising from 5 to 80 weight percent of a substrate rubber having a glass transition temperature below 0.degree. C. and from 95 to 20 weight percent of monomers comprising per 100 parts by weight of the monomers from 20 to 75 parts by weight of a vinyl aromatic monomer and from 80 to 25 parts by weight of polar monomer selected from the group consisting of C.sub.1 to C.sub.4 alkyl (meth)-acrylate and (meth)-acrylonitrile, said monomers having been polymerized in the presence of and grafted on to the substrate rubber; (B) a polyamide; (C) an acid-containing ethylene/alkyl acrylate copolymer rubber having a glass transition temperature below 0.degree. C., said rubber consisting of ethylene, C.sub.1 to C.sub.4 alkyl acrylate and 0.5 to 25 mole percent of an interpolymerized acid-containing monomer selected from (meth)-acrylic acid, a dicarboxylic acid or annhydride or a C.sub.1 to C 12 monoalkyl ester of a dicarboxylic acid; and (D) an effective amount of an acid-containing terpolymer to improve the impact resistance of the polymer blend comprising components (A), (B) and (C), said acid-containing terpolymer having a glass transition temperature above 0.degree. C. and consisting of a vinyl aromatic monomer, a polar monomer selected from the group consisting of C.sub.1 to C.sub.4 alkyl (meth)arcylate and (meth) acrylonitrile and from about 0.05 to about 50 mole percent of acid functional comonomer units selected from (meth)acrylic acid, a dicarboxylic acid or anhydride or a C.sub.1 to C 12 monoalkyl ester of a dicarboxylic acid; wherein the weight ratio of component (A) to component (B) is in the range of about 1:9 to about 9:1, wherein the sum of components (A) and (B) is at least about 60 weight percent of the polymer blend and wherein the amount of component (C) is in the range of 1 to 18 weight percent of the polymer blend and the amount of component (D) is in the range of 0.05 to 20 weight percent.
2. The polymer blend of claim 1 wherein the substrate rubber is polybutadiene or a butadiene copolymer and the monomers grafted thereto are styrene and (meth)-acrylonitrile or methyl methacrylate.
3. The polymer blend of claim 1 wherein the graft monomers of component (A) comprise 25 to 50 parts by weight of acrylonitrile and 50 to 75 parts by weight of a vinyl aromatic monomer per 100 parts by weight of the monomers.
4. The polymer blend of claim 1 wherein component (B) is nylon 6, nylon 6,6 or a copolymer of nylon 6,6 and nylon 6.
5. The polymer blend of claim 1 wherein component (D) contains 0.1 to 30.0 mole percent of the acid functional comonomer.
6. The polymer blend of claim 5 wherein the total weight percent of acid comonomer and polar monomers of component (D) is equal to the total weight percent of polar monomers of component (A) .+-.12 percentage units, and wherein the total weight percent of acid comonomer and polar monomers of component (D) is at least 15 weight percent of component (D).
7. The polymer blend of claim 6 wherein the total weight percent of acid comonomer and polar monomers of component (D) is equal to the weight percent of polar monomers of component (A) .+-.7 percentage units.
8. The polymer blend of claim 6 wherein except for the acid comonomer of component (D), the monomers of component (D) are identical to the monomers of component (A).
9. The polymer blend of claim 6 wherein the concentration of acid functional monomer units provided by component (D) is in the range of 0.00003 to about 0.005 mole per 100 parts by weight of polyblend.
10. The polymer blend of claim 6 wherein component (D) is a terpolymer of styrene, acrylonitrile and maleic anhydride and the maleic anhydride comprises 0.1 to 3.0 mole percent of the terpolymer.
11. The polymer blend of claim 10 wherein the maleic anhydride comprises about 1 mole percent of the terpolymer.
12. The polymer blend of claim 6 wherein component (D) is a terpolymer of styrene, methyl methacrylate and maleic anhydride and the maleic anhydride comprises from about 15 to 25 mole percent of the terpolymer.
13. The polymer blend of claim 12 wherein the maleic anhydride comprises about 22 mole percent of the terpolymer.
14. The polymer blend of claim 6 wherein component (C) is a copolymer comprising at least 50 mole percent ethylene, about 0.5 to about 10 mole percent acrylic acid or monoethyl maleate and about 10 to 49.5 mole percent C.sub.1 to C.sub.4 alkyl acrylate.
15. The polymer blend of claim 14 wherein component (C) provides from 5 to 15 weight percent of the polyblend.
16. A shaped article prepared from a polymer blend according to claim 1.
Patent Citations (3)
| Patent | Date | Inventor | Cited By |
|---|---|---|---|
| US4554320 | 1985-11-01 | Reimann et al. | |
| DEX3120803 | 1982-12-01 | ||
| JPX54-48850 | 1979-04-01 |