JPS623181B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to polyamide molding materials toughened by polymeric reinforcing agents, and more particularly to polyamide blends. Improving the impact strength of polyamide resins has long been of interest because resistance to fracture or brittle fracture of polyamide molded products is a desirable property for any molded product. The tendency to fracture brittlely (rather than ductilely) upon impact is a major limitation to the usefulness of such products. “Ductile” means that cracks do not tend to grow out of the area of impact;
Therefore, a resin with good ductility will resist crack growth caused by impact. The ductility of the product is determined by the notched Izot test ASTM D-
256-73. Conventionally, various additives have been added to polyamide resins to improve strength and ductility. For example, Ebstein's U.S. Patent 4174358
No. 1, published November 13, 1979, describes improvements in impact strength and ductility through the addition of selected random copolymers that adhere to polyamides. however,
Generally, the tendency of polyamides to fail brittlely on impact increases as temperature decreases. Thus, the use of molded products for low temperature applications, such as, for example, winter sports equipment, automobile bumpers, etc., is decreasing. It would be desirable to have polyamide molding blends suitable for the production of molded articles for low temperature applications. The present invention is directed to such molding blends. The present invention provides polyamide blends with good impact strength and ductility at low temperatures, such as 0°C. This blend comprises (a) 20-80% by weight of 66 nylon and supplementary 80-20
60-97% by weight of polyamide, which is a mixture of 6% by weight of nylon, and (b) 3-40% by weight, preferably 10-30% by weight of (i) carboxyl or carboxylate functional groups. or (ii) a third copolymerizable monomer, the acid moiety being at least partially ionized by the metal ion. - olefin and at least 1 α・
A polyamide blend comprising an ionic copolymer of β-unsaturated carboxylic acid, and a polymeric reinforcing agent selected from the following. The expression "elastomeric" means that the copolymer after molding substantially recovers its original shape after removal of the pressure that caused the deformation. "Olefinic" means terminally unsaturated monomers including dienes and the like. "Copolymer" means a polymer composed of two or more different monomer units. It has been discovered that the best low temperature toughness of compositions containing polymeric tougheners (b)(i) and (b)(ii) is achieved when using a blend of nylon 66 and nylon 6. Ta. To be clear, blends are about 20% or more and about 80%
% or less of nylon 6.
Thus, compositions containing only nylon 66 or only nylon 6 experience only relatively low reinforcement at low temperatures with a given reinforcement. Moreover, the behavior of blends of 66 and 6 nylons is similar to that of compositions based on other nylon blends, such as 6/612 or 66/612 nylons, compared to compositions containing only one of both nylon components. It is unique in that it has inferior low temperature toughness. Nylon 66 and nylon 6 are commonly known and available. Nylon 66 is polyhexamethylene adipamide, while nylon 6 is polycaprolactam. Both are polymers with high or film-forming molecular weights. Reinforcing component (b)(i) is an elastomeric olefin-based copolymer with carboxyl or carboxylate functionality. The olefin moiety may be 2 to 2, such as ethylene, propylene, etc.
Derived from an 8-carbon alkylene monomer. However, the olefin moiety can also include dienes, such as butadiene. The comonomers present can be a wide variety of copolymerizable ethylenically unsaturated monomers. Generally, the comonomer is a lower alkyl acrylate or methacrylate, such as methyl acrylate, ethyl acrylate or isobutyl acrylate, or other olefins or mixtures thereof. Comonomers can also be methacrylic or acrylic acid, fumaric acid, maleic anhydride, glycidyl methacrylate, and the like. In a preferred embodiment, component (b)(i) is a polymer of ethylene, at least one _C3 - _C6 alpha-olefin and at least one non-conjugated diene;
The polymer contains carboxyl or carboxylate functionality. In the production of such polymers, propylene is usually chosen as the _C3 - _C6 alpha-olefin. In the production of elastomeric polymers, instead of or in addition to propylene, other C ₃ -C ₆ α-olefins, namely 1-butene, 1-pentene,
and 1-hexene. Preferably, the non-conjugated diene is monoreactive. Monoreactive nonconjugated dienes have a first double bond that readily participates in the polymerization reaction with ethylene and propylene and a second double bond that does not participate appreciably in the polymerization reaction. . Monoreactive non-functional dienes are linear aliphatic dienes of at least 6 carbon atoms with one terminal double bond and one internal double bond, and one or both carbon-carbon double bonds are connected to a carbocyclic ring. Includes cyclic dienes that are part of the ring of formula. The non-conjugated diene may be di-reactive. "Bireactive" means that both double bonds can be polymerized during the preparation of the polymer. Such a di-reactive diene is 2.5
-norbonadiene and 1,7-octadiene. Carboxyl or carboxylate functionality is usually provided by using ethylenically unsaturated comonomers containing carboxyl or carboxylate groups as comonomers in the copolymer. With respect to preferred component (b)(i), the carboxyl or carboxylate functionality is an ethylene/ _C3 - _C6 alpha-olefin/non-conjugated diene with an alpha-beta-ethylenically unsaturated diene having from 4 to 8 carbon atoms. It can be provided by reaction with an unsaturated compound selected from the class consisting of saturated dicarboxylic acids or their derivatives. Such derivatives are monoesters of alcohols of 1 to 29 carbon atoms, anhydrides of dicarboxylic acids, or metal salts of acids;
Alternatively, by neutralization with a metal basic salt,
Includes monoesters of dicarboxylic acids with 100% ionized carboxylic acid groups. Examples of such acids and derivatives are maleic acid, maleic anhydride monoethyl ester, metal salts of maleic acid monoester, fumaric acid, fumaric acid monoethyl ester, itaconic acid, vinylbenzoic acid, vinyl phthalic acid, fumaric acid. Metal salts of monoethyl esters, maleic acid when the alcohol moiety is methyl, propyl, isopropyl, butyl, isobutyl, hexyl, cyclohexyl, octyl, 2-ethylhexyl, decyl, stearyl, methoxyethyl, ethoxyethyl, hydroxy or ethyl; monoesters of fumaric acid or itaconic acid. The adduct is prepared by a grafting process in which the unsaturated acids or derivatives thereof are mixed well without appreciable free radical formation and the mixture is simultaneously or subsequently heated to a temperature at which thermal addition occurs. I can do it. The temperature selected will generally be at least 225°C to achieve adduct formation at an acceptable rate and less than about 450°C to prevent excessive polymer degradation. Suitable temperature ranges will vary depending on the particular polymer, but can be readily determined by one skilled in the art. The acid or derivative thereof and the polymer may be mixed by blending in an internal mixer or extruder, or by kneading the finely ground dry compound and polymer on a well-ventilated rubber roll mill and heating simultaneously; Alternatively, it can be carried out by subsequent heating, for example in a hot press or a mold. The acid or derivative may be substituted with groups such as bromine or chlorine that do not unduly interfere with the grafting reaction. Generally about 0.5-9% by weight, preferably about 1-9% by weight
It is desirable to form an adduct containing 4% by weight of acid or derivative. Reinforcing component (b)(ii) is derived from an alpha-olefin and an unsaturated carboxylic acid and optionally further copolymerizable comonomers. Preferably, the α-olefin is ethylene and the acid is acrylic acid or methacrylic acid. Other copolymerizable comonomers may include acrylic esters or methacrylic esters. Metal ions include 1, such as Na, Zn, Al, K, etc.
It can be valent, divalent or trivalent. Typical component (b) tougheners are: ethylene/isobutyl acrylate/methacrylic acid (80/10/10) neutralized 70% with zinc, butadiene/acrylonitrile with carboxyl end groups, ethylene/methacrylate ester/maleic acid. Including acid monoethyl ester (42/54/14), ethylene/vinyl acetate/glycidyl methacrylate (70/25/5), continuously polymerized methacrylate ester/butyl acrylate/acrylic acid copolymer. do. Blends of the present invention are prepared by mixing the components in the indicated proportions and melt blending them into a homogeneous mixture. Preferably, the nylon 6, nylon 66 and reinforcing polymer or polymers are first mixed by rolling in a drum. Melt blending can typically be carried out at a temperature above the melting point of each component and below the decomposition temperature. A temperature range of about 260-330°C is preferred. These blends are particularly suitable for applications where impact strength at low temperatures is important, such as for example car bumpers, driving gear, safety equipment, etc. There is. Blends of the invention include, for example, stabilizers and inhibitors against oxidative, thermal and UV degradation; lubricants and mold release agents; colorants, including dyes and pigments;
One or more conventional additives may also be included, such as flame retardants, fibrous and pulverulent fillers and reinforcing agents, plasticizers, etc. These additives are generally added during the mixing stage. Typical oxidative and thermal stabilizers that may be present in the blends of the present invention include group metal halides such as sodium, potassium, lithium and cuprous halides such as chlorides, bromides, iodides; Hindered phenols, hydroquinones and various substitutes of these classes and combinations thereof. Representative UV stabilizers include various substituted resorcinols, salicylates, benzotriazoles, benzophenones, and the like. Typical lubricants and mold release agents include stearic acid, stearyl alcohol, and stearamides. Representative organic dyes include nigrosine, and representative pigments include titanium dioxide,
Includes cadmium sulfide, cadmium selenide, phthalocyanines, ultramarine blue, carbon black, etc. Typical fillers include carbon fiber, glass fiber, amorphous silica, asbestos, calcium silicate, aluminum silicate, magnesium carbonate, kaolin, chalk, powdered quartz, mica,
Typical flame retardants include organic halogenated compounds, such as decabromodiphenyl ether, including feldspar, and the like. EXAMPLES The present invention is further illustrated by the following specific examples, in which parts and percentages are by weight unless otherwise indicated. In these examples, the components are mixed by rolling in a drum. The mixture is then pelletized by melt mixing in a Werner and Preidler twin screw extruder at a barrel temperature of 310-320°C and a die temperature of 290°C. Extrusion can be carried out with a port open to air, or if removal of caprolactam monomer is desired,
Perform under vacuum. The screw speed is 200 revolutions/min. The resulting strands are quenched in water, cut into pellets, and sparged with nitrogen until cool to remove moisture. 10~30℃ higher than the melting point of polyamide matrix
Test specimens (1/2 x 5 x 1/4 inch) are molded in 3 oz and 6 oz injection molding machines at high melt temperature. The molding temperature is approximately 70° C. with rapid injection and a 20/40 molding cycle (ram advance seconds/hold seconds) is used. The molded specimens are tested in the as-formed dry state using the following test procedure: Notched Izot Toughness: ASTM D-256-73. In this test,
The specimen is 1/2 x 3 x 1/4 inch and has a 10
It has a mil (radius) notch. Tensile strength: ASTM D-638-58T Elongation: ASTM D-638-58T Flexural modulus: ASTM D-790-58T In the examples, the 66 nylon used has a relative viscosity of about 52, while the 66 nylon used has a relative viscosity of about 52. -Nylon is
It has a relative viscosity of 75-90. These relative viscosities were determined with 8.4% polymer solutions in 90% formic acid. The EPDM used in the tables and examples is 72% ethylene, 24% propylene and 4% 1.4-
Represents a copolymer consisting of hexadiene. It is used as a filler for reinforcing polymers. EPDM-FA contains 68% ethylene, 26% propylene, 6% 1,4-hexadiene and 0.06%
% of 2,5-norbornadiene, from 1.5 to 2.0 as measured by infrared (CPE671 spectrophotometer).
% functionality (acid and anhydride), and
It represents a reinforcing copolymer having a melt flow of 1.2 to 4.8 g/10 min at 280°C through a 0.0825 inch diameter orifice. Examples 1, 2 and Control A 66 nylon, 6 nylon, EPDM and EPDM
-FA was mixed, pelletized, formed into bar specimens and tested for notched Izot values as described above. The amounts and test results for each ingredient are shown below:

[Table] In either case, resins containing nylon 6 and nylon 66 have the following properties when measured by this test:
It can be seen that it has much higher impact strength than the control (which does not contain nylon 6). Examples 3, 4 and 5 and Control Examples B, C, D and E In another series of experiments, 66 nylon, 6 nylon, EPDM and EPDM-FA were blended and
The pellets were formed into pellets, formed into bar specimens, and tested for notched Izot values as described above. The amounts of ingredients and test results are shown below.

[Table] 66 nylon only, 6 nylon only, or a copolymer of 66 nylon and 6 nylon,
It is clear that the mixtures of nylon 66 and nylon 6 shown in Examples 3, 4, and 5 do not provide resins with as good notched isot strength. Example 6 and Control Example F The resins listed in the table below are 20% based on the weight of the resin.
of polydibromophenylene oxide and 8% of
They were prepared, molded, and tested as described above, except that a flame retardant system consisting of Sb ₂ O ₃ was also added.

[Table] It can be seen that the presence of Nylon 6 increases the strength even in the presence of flame retardants. Example 7 and Control Example G The following resins are prepared as described above:

[Table] In a 2 1/2 inch Stirling single screw extruder,
67% of each was mixed with 33% cut glass fiber, and the obtained specimens were subjected to a notched Izot test, and the following results were obtained:

It can be seen that the presence of Nylon 6 increases the strength even when cut glass fibers are present. Example 8 and Control Examples H and I The following resins were prepared, molded, and tested for notched isot toughness in a manner similar to the general method described above.

Table: Example 9 and Comparative Examples J and K Following the general procedure described above, the following resins were prepared, molded and tested for notched isot toughness.

Table: Example 10 and Control Examples L and M Following the general procedure described above, the following resins were prepared, molded and tested for notched isot toughness.

【table】

Claims (1)

[Scope of Claims] 1 (a) 20 to 80% by weight of 66 nylon and supplementary 80
60, which is a mixture of ~20% by weight 6-nylon
~97% by weight polyamide, and optionally (b) 3 to 40% by weight (i) an elastomeric olefinic copolymer having carboxyl or carboxylate functionality, or (ii) a third copolymerizable at least one alpha-olefin and at least one alpha-beta monomer, the acid moiety being at least partially ionized by neutralization with a basic salt of the metal. A polyamide blend, characterized in that it contains a polymeric reinforcing agent selected from any of the following: ionic copolymers of unsaturated carboxylic acids. 2. A blend according to claim 1, wherein component (b) is defined as in component (b)(i). 3. The blend according to claim 2, wherein component (b)(i) is a copolymer of ethylene/methacrylic acid/maleic acid monoester. 4. A blend according to claim 2, wherein component (b)(i) is a butadiene/acrylonitrile copolymer having carboxyl end groups. 5. A blend according to claim 1, wherein component (b) is defined as in component (b)(ii). 6 Component (b)(ii) is 70% zinc neutralized ethylene/
The blend according to claim 5, which is a copolymer of isobutyl acrylate/methacrylic acid. 7 (a) 20-80% by weight of 66 nylon and supplementary 80
60~, which is a mixture of ~20% by weight nylon 6
97% by weight of polyamide, and supplementary (b) 3 to 40% by weight (i) 0 to 80% by weight of ethylene, at least 1
of _C3 to _C6 alpha-olefin and at least one non-conjugated diene, and supplementary (ii) 20 to 100% by weight of ethylene, having carboxyl or carboxylate functionality;
A polyamide blend, characterized in that it contains an elastomeric reinforcement consisting of a polymer of at least one _C3 - _C6 alpha-olefin and at least one non-conjugated diene. 8. A blend according to claim 7, wherein component (b) is present in an amount of 10 to 30% by weight. 9 Component (b)(ii) is ethylene, at least one C ₃ ~
8. A blend according to claim 7, which is an adduct of a polymer of C ₆ α-olefin and at least one non-conjugated diene with an unsaturated compound containing carboxyl or carboxyl-derived groups. 10 The diene is 1,4-hexadiene,
10. A blend according to claim 9, wherein the _C3 - _C6 alpha-olefin is propylene and the unsaturated compound containing carboxyl or carboxyl-derived groups is fumaric acid. 11 (a) 20-80% by weight of 66 nylon and supplementary
is a mixture of 80-20% by weight 6-nylon,
60-97% by weight polyamide, and optionally (b) 3-40% by weight (i) an elastomeric olefinic copolymer having carboxyl or carboxylate functionality, or (ii) a third copolymer. at least one alpha-olefin and at least one alpha-olefin and at least one alpha-beta monomer, the acid moiety being at least partially ionized by neutralization with a basic salt of the metal. - an ionic copolymer of an unsaturated carboxylic acid, wherein the above components (a) and (b) are physically mixed and then melt-blended with a polymeric reinforcing agent selected from the following. A method for producing a polyamide blend containing the same.